feat: 完成TCP2UART透传核心集成

集成CH390驱动、LwIP协议栈和FreeRTOS多任务透传框架，确保TCP Server/Client与UART链路按配置稳定联动。

Drivers/LwIP/src/core/altcp.c

@@ -0,0 +1,717 @@
+/**
+ * @file
+ * @defgroup altcp Application layered TCP Functions
+ * @ingroup altcp_api
+ *
+ * This file contains the common functions for altcp to work.
+ * For more details see @ref altcp_api.
+ */
+
+/**
+ * @defgroup altcp_api Application layered TCP Introduction
+ * @ingroup callbackstyle_api
+ *
+ * Overview
+ * --------
+ * altcp (application layered TCP connection API; to be used from TCPIP thread)
+ * is an abstraction layer that prevents applications linking hard against the
+ * @ref tcp.h functions while providing the same functionality. It is used to
+ * e.g. add SSL/TLS (see LWIP_ALTCP_TLS) or proxy-connect support to an application
+ * written for the tcp callback API without that application knowing the
+ * protocol details.
+ *
+ * * This interface mimics the tcp callback API to the application while preventing
+ *   direct linking (much like virtual functions).
+ * * This way, an application can make use of other application layer protocols
+ *   on top of TCP without knowing the details (e.g. TLS, proxy connection).
+ * * This is achieved by simply including "lwip/altcp.h" instead of "lwip/tcp.h",
+ *   replacing "struct tcp_pcb" with "struct altcp_pcb" and prefixing all functions
+ *   with "altcp_" instead of "tcp_".
+ *
+ * With altcp support disabled (LWIP_ALTCP==0), applications written against the
+ * altcp API can still be compiled but are directly linked against the tcp.h
+ * callback API and then cannot use layered protocols. To minimize code changes
+ * in this case, the use of altcp_allocators is strongly suggested.
+ *
+ * Usage
+ * -----
+ * To make use of this API from an existing tcp raw API application:
+ * * Include "lwip/altcp.h" instead of "lwip/tcp.h"
+ * * Replace "struct tcp_pcb" with "struct altcp_pcb"
+ * * Prefix all called tcp API functions with "altcp_" instead of "tcp_" to link
+ *   against the altcp functions
+ * * @ref altcp_new (and @ref altcp_new_ip_type / @ref altcp_new_ip6) take
+ *   an @ref altcp_allocator_t as an argument, whereas the original tcp API
+ *   functions take no arguments.
+ * * An @ref altcp_allocator_t allocator is an object that holds a pointer to an
+ *   allocator object and a corresponding state (e.g. for TLS, the corresponding
+ *   state may hold certificates or keys). This way, the application does not
+ *   even need to know if it uses TLS or pure TCP, this is handled at runtime
+ *   by passing a specific allocator.
+ * * An application can alternatively bind hard to the altcp_tls API by calling
+ *   @ref altcp_tls_new or @ref altcp_tls_wrap.
+ * * The TLS layer is not directly implemented by lwIP, but a port to mbedTLS is
+ *   provided.
+ * * Another altcp layer is proxy-connect to use TLS behind a HTTP proxy (see
+ *   @ref altcp_proxyconnect.h)
+ *
+ * altcp_allocator_t
+ * -----------------
+ * An altcp allocator is created by the application by combining an allocator
+ * callback function and a corresponding state, e.g.:\code{.c}
+ * static const unsigned char cert[] = {0x2D, ... (see mbedTLS doc for how to create this)};
+ * struct altcp_tls_config * conf = altcp_tls_create_config_client(cert, sizeof(cert));
+ * altcp_allocator_t tls_allocator = {
+ *   altcp_tls_alloc, conf
+ * };
+ * \endcode
+ *
+ *
+ * struct altcp_tls_config
+ * -----------------------
+ * The struct altcp_tls_config holds state that is needed to create new TLS client
+ * or server connections (e.g. certificates and private keys).
+ *
+ * It is not defined by lwIP itself but by the TLS port (e.g. altcp_tls to mbedTLS
+ * adaption). However, the parameters used to create it are defined in @ref
+ * altcp_tls.h (see @ref altcp_tls_create_config_server_privkey_cert for servers
+ * and @ref altcp_tls_create_config_client / @ref altcp_tls_create_config_client_2wayauth
+ * for clients).
+ *
+ * For mbedTLS, ensure that certificates can be parsed by 'mbedtls_x509_crt_parse()' and
+ * private keys can be parsed by 'mbedtls_pk_parse_key()'.
+ */
+
+/*
+ * Copyright (c) 2017 Simon Goldschmidt
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Simon Goldschmidt <goldsimon@gmx.de>
+ *
+ */
+
+#include "lwip/opt.h"
+
+#if LWIP_ALTCP /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/altcp.h"
+#include "lwip/priv/altcp_priv.h"
+#include "lwip/altcp_tcp.h"
+#include "lwip/tcp.h"
+#include "lwip/mem.h"
+
+#include <string.h>
+
+extern const struct altcp_functions altcp_tcp_functions;
+
+/**
+ * For altcp layer implementations only: allocate a new struct altcp_pcb from the pool
+ * and zero the memory
+ */
+struct altcp_pcb *
+altcp_alloc(void)
+{
+  struct altcp_pcb *ret = (struct altcp_pcb *)memp_malloc(MEMP_ALTCP_PCB);
+  if (ret != NULL) {
+    memset(ret, 0, sizeof(struct altcp_pcb));
+  }
+  return ret;
+}
+
+/**
+ * For altcp layer implementations only: return a struct altcp_pcb to the pool
+ */
+void
+altcp_free(struct altcp_pcb *conn)
+{
+  if (conn) {
+    if (conn->fns && conn->fns->dealloc) {
+      conn->fns->dealloc(conn);
+    }
+    memp_free(MEMP_ALTCP_PCB, conn);
+  }
+}
+
+/**
+ * @ingroup altcp
+ * altcp_new_ip6: @ref altcp_new for IPv6
+ */
+struct altcp_pcb *
+altcp_new_ip6(altcp_allocator_t *allocator)
+{
+  return altcp_new_ip_type(allocator, IPADDR_TYPE_V6);
+}
+
+/**
+ * @ingroup altcp
+ * altcp_new: @ref altcp_new for IPv4
+ */
+struct altcp_pcb *
+altcp_new(altcp_allocator_t *allocator)
+{
+  return altcp_new_ip_type(allocator, IPADDR_TYPE_V4);
+}
+
+/**
+ * @ingroup altcp
+ * altcp_new_ip_type: called by applications to allocate a new pcb with the help of an
+ * allocator function.
+ *
+ * @param allocator allocator function and argument
+ * @param ip_type IP version of the pcb (@ref lwip_ip_addr_type)
+ * @return a new altcp_pcb or NULL on error
+ */
+struct altcp_pcb *
+altcp_new_ip_type(altcp_allocator_t *allocator, u8_t ip_type)
+{
+  struct altcp_pcb *conn;
+  if (allocator == NULL) {
+    /* no allocator given, create a simple TCP connection */
+    return altcp_tcp_new_ip_type(ip_type);
+  }
+  if (allocator->alloc == NULL) {
+    /* illegal allocator */
+    return NULL;
+  }
+  conn = allocator->alloc(allocator->arg, ip_type);
+  if (conn == NULL) {
+    /* allocation failed */
+    return NULL;
+  }
+  return conn;
+}
+
+/**
+ * @ingroup altcp
+ * @see tcp_arg()
+ */
+void
+altcp_arg(struct altcp_pcb *conn, void *arg)
+{
+  if (conn) {
+    conn->arg = arg;
+  }
+}
+
+/**
+ * @ingroup altcp
+ * @see tcp_accept()
+ */
+void
+altcp_accept(struct altcp_pcb *conn, altcp_accept_fn accept)
+{
+  if (conn != NULL) {
+    conn->accept = accept;
+  }
+}
+
+/**
+ * @ingroup altcp
+ * @see tcp_recv()
+ */
+void
+altcp_recv(struct altcp_pcb *conn, altcp_recv_fn recv)
+{
+  if (conn) {
+    conn->recv = recv;
+  }
+}
+
+/**
+ * @ingroup altcp
+ * @see tcp_sent()
+ */
+void
+altcp_sent(struct altcp_pcb *conn, altcp_sent_fn sent)
+{
+  if (conn) {
+    conn->sent = sent;
+  }
+}
+
+/**
+ * @ingroup altcp
+ * @see tcp_poll()
+ */
+void
+altcp_poll(struct altcp_pcb *conn, altcp_poll_fn poll, u8_t interval)
+{
+  if (conn) {
+    conn->poll = poll;
+    conn->pollinterval = interval;
+    if (conn->fns && conn->fns->set_poll) {
+      conn->fns->set_poll(conn, interval);
+    }
+  }
+}
+
+/**
+ * @ingroup altcp
+ * @see tcp_err()
+ */
+void
+altcp_err(struct altcp_pcb *conn, altcp_err_fn err)
+{
+  if (conn) {
+    conn->err = err;
+  }
+}
+
+/* Generic functions calling the "virtual" ones */
+
+/**
+ * @ingroup altcp
+ * @see tcp_recved()
+ */
+void
+altcp_recved(struct altcp_pcb *conn, u16_t len)
+{
+  if (conn && conn->fns && conn->fns->recved) {
+    conn->fns->recved(conn, len);
+  }
+}
+
+/**
+ * @ingroup altcp
+ * @see tcp_bind()
+ */
+err_t
+altcp_bind(struct altcp_pcb *conn, const ip_addr_t *ipaddr, u16_t port)
+{
+  if (conn && conn->fns && conn->fns->bind) {
+    return conn->fns->bind(conn, ipaddr, port);
+  }
+  return ERR_VAL;
+}
+
+/**
+ * @ingroup altcp
+ * @see tcp_connect()
+ */
+err_t
+altcp_connect(struct altcp_pcb *conn, const ip_addr_t *ipaddr, u16_t port, altcp_connected_fn connected)
+{
+  if (conn && conn->fns && conn->fns->connect) {
+    return conn->fns->connect(conn, ipaddr, port, connected);
+  }
+  return ERR_VAL;
+}
+
+/**
+ * @ingroup altcp
+ * @see tcp_listen_with_backlog_and_err()
+ */
+struct altcp_pcb *
+altcp_listen_with_backlog_and_err(struct altcp_pcb *conn, u8_t backlog, err_t *err)
+{
+  if (conn && conn->fns && conn->fns->listen) {
+    return conn->fns->listen(conn, backlog, err);
+  }
+  return NULL;
+}
+
+/**
+ * @ingroup altcp
+ * @see tcp_abort()
+ */
+void
+altcp_abort(struct altcp_pcb *conn)
+{
+  if (conn && conn->fns && conn->fns->abort) {
+    conn->fns->abort(conn);
+  }
+}
+
+/**
+ * @ingroup altcp
+ * @see tcp_close()
+ */
+err_t
+altcp_close(struct altcp_pcb *conn)
+{
+  if (conn && conn->fns && conn->fns->close) {
+    return conn->fns->close(conn);
+  }
+  return ERR_VAL;
+}
+
+/**
+ * @ingroup altcp
+ * @see tcp_shutdown()
+ */
+err_t
+altcp_shutdown(struct altcp_pcb *conn, int shut_rx, int shut_tx)
+{
+  if (conn && conn->fns && conn->fns->shutdown) {
+    return conn->fns->shutdown(conn, shut_rx, shut_tx);
+  }
+  return ERR_VAL;
+}
+
+/**
+ * @ingroup altcp
+ * @see tcp_write()
+ */
+err_t
+altcp_write(struct altcp_pcb *conn, const void *dataptr, u16_t len, u8_t apiflags)
+{
+  if (conn && conn->fns && conn->fns->write) {
+    return conn->fns->write(conn, dataptr, len, apiflags);
+  }
+  return ERR_VAL;
+}
+
+/**
+ * @ingroup altcp
+ * @see tcp_output()
+ */
+err_t
+altcp_output(struct altcp_pcb *conn)
+{
+  if (conn && conn->fns && conn->fns->output) {
+    return conn->fns->output(conn);
+  }
+  return ERR_VAL;
+}
+
+/**
+ * @ingroup altcp
+ * @see tcp_mss()
+ */
+u16_t
+altcp_mss(struct altcp_pcb *conn)
+{
+  if (conn && conn->fns && conn->fns->mss) {
+    return conn->fns->mss(conn);
+  }
+  return 0;
+}
+
+/**
+ * @ingroup altcp
+ * @see tcp_sndbuf()
+ */
+u16_t
+altcp_sndbuf(struct altcp_pcb *conn)
+{
+  if (conn && conn->fns && conn->fns->sndbuf) {
+    return conn->fns->sndbuf(conn);
+  }
+  return 0;
+}
+
+/**
+ * @ingroup altcp
+ * @see tcp_sndqueuelen()
+ */
+u16_t
+altcp_sndqueuelen(struct altcp_pcb *conn)
+{
+  if (conn && conn->fns && conn->fns->sndqueuelen) {
+    return conn->fns->sndqueuelen(conn);
+  }
+  return 0;
+}
+
+void
+altcp_nagle_disable(struct altcp_pcb *conn)
+{
+  if (conn && conn->fns && conn->fns->nagle_disable) {
+    conn->fns->nagle_disable(conn);
+  }
+}
+
+void
+altcp_nagle_enable(struct altcp_pcb *conn)
+{
+  if (conn && conn->fns && conn->fns->nagle_enable) {
+    conn->fns->nagle_enable(conn);
+  }
+}
+
+int
+altcp_nagle_disabled(struct altcp_pcb *conn)
+{
+  if (conn && conn->fns && conn->fns->nagle_disabled) {
+    return conn->fns->nagle_disabled(conn);
+  }
+  return 0;
+}
+
+/**
+ * @ingroup altcp
+ * @see tcp_setprio()
+ */
+void
+altcp_setprio(struct altcp_pcb *conn, u8_t prio)
+{
+  if (conn && conn->fns && conn->fns->setprio) {
+    conn->fns->setprio(conn, prio);
+  }
+}
+
+err_t
+altcp_get_tcp_addrinfo(struct altcp_pcb *conn, int local, ip_addr_t *addr, u16_t *port)
+{
+  if (conn && conn->fns && conn->fns->addrinfo) {
+    return conn->fns->addrinfo(conn, local, addr, port);
+  }
+  return ERR_VAL;
+}
+
+ip_addr_t *
+altcp_get_ip(struct altcp_pcb *conn, int local)
+{
+  if (conn && conn->fns && conn->fns->getip) {
+    return conn->fns->getip(conn, local);
+  }
+  return NULL;
+}
+
+u16_t
+altcp_get_port(struct altcp_pcb *conn, int local)
+{
+  if (conn && conn->fns && conn->fns->getport) {
+    return conn->fns->getport(conn, local);
+  }
+  return 0;
+}
+
+#if LWIP_TCP_KEEPALIVE
+void
+altcp_keepalive_disable(struct altcp_pcb *conn)
+{
+  if (conn && conn->fns && conn->fns->keepalive_disable) {
+    conn->fns->keepalive_disable(conn);
+  }
+}
+
+void
+altcp_keepalive_enable(struct altcp_pcb *conn, u32_t idle, u32_t intvl, u32_t count)
+{
+  if (conn && conn->fns && conn->fns->keepalive_enable) {
+      conn->fns->keepalive_enable(conn, idle, intvl, count);
+  }
+}
+#endif
+
+#ifdef LWIP_DEBUG
+enum tcp_state
+altcp_dbg_get_tcp_state(struct altcp_pcb *conn)
+{
+  if (conn && conn->fns && conn->fns->dbg_get_tcp_state) {
+    return conn->fns->dbg_get_tcp_state(conn);
+  }
+  return CLOSED;
+}
+#endif
+
+/* Default implementations for the "virtual" functions */
+
+void
+altcp_default_set_poll(struct altcp_pcb *conn, u8_t interval)
+{
+  if (conn && conn->inner_conn) {
+    altcp_poll(conn->inner_conn, conn->poll, interval);
+  }
+}
+
+void
+altcp_default_recved(struct altcp_pcb *conn, u16_t len)
+{
+  if (conn && conn->inner_conn) {
+    altcp_recved(conn->inner_conn, len);
+  }
+}
+
+err_t
+altcp_default_bind(struct altcp_pcb *conn, const ip_addr_t *ipaddr, u16_t port)
+{
+  if (conn && conn->inner_conn) {
+    return altcp_bind(conn->inner_conn, ipaddr, port);
+  }
+  return ERR_VAL;
+}
+
+err_t
+altcp_default_shutdown(struct altcp_pcb *conn, int shut_rx, int shut_tx)
+{
+  if (conn) {
+    if (shut_rx && shut_tx && conn->fns && conn->fns->close) {
+      /* default shutdown for both sides is close */
+      return conn->fns->close(conn);
+    }
+    if (conn->inner_conn) {
+      return altcp_shutdown(conn->inner_conn, shut_rx, shut_tx);
+    }
+  }
+  return ERR_VAL;
+}
+
+err_t
+altcp_default_write(struct altcp_pcb *conn, const void *dataptr, u16_t len, u8_t apiflags)
+{
+  if (conn && conn->inner_conn) {
+    return altcp_write(conn->inner_conn, dataptr, len, apiflags);
+  }
+  return ERR_VAL;
+}
+
+err_t
+altcp_default_output(struct altcp_pcb *conn)
+{
+  if (conn && conn->inner_conn) {
+    return altcp_output(conn->inner_conn);
+  }
+  return ERR_VAL;
+}
+
+u16_t
+altcp_default_mss(struct altcp_pcb *conn)
+{
+  if (conn && conn->inner_conn) {
+    return altcp_mss(conn->inner_conn);
+  }
+  return 0;
+}
+
+u16_t
+altcp_default_sndbuf(struct altcp_pcb *conn)
+{
+  if (conn && conn->inner_conn) {
+    return altcp_sndbuf(conn->inner_conn);
+  }
+  return 0;
+}
+
+u16_t
+altcp_default_sndqueuelen(struct altcp_pcb *conn)
+{
+  if (conn && conn->inner_conn) {
+    return altcp_sndqueuelen(conn->inner_conn);
+  }
+  return 0;
+}
+
+void
+altcp_default_nagle_disable(struct altcp_pcb *conn)
+{
+  if (conn && conn->inner_conn) {
+    altcp_nagle_disable(conn->inner_conn);
+  }
+}
+
+void
+altcp_default_nagle_enable(struct altcp_pcb *conn)
+{
+  if (conn && conn->inner_conn) {
+    altcp_nagle_enable(conn->inner_conn);
+  }
+}
+
+int
+altcp_default_nagle_disabled(struct altcp_pcb *conn)
+{
+  if (conn && conn->inner_conn) {
+    return altcp_nagle_disabled(conn->inner_conn);
+  }
+  return 0;
+}
+
+void
+altcp_default_setprio(struct altcp_pcb *conn, u8_t prio)
+{
+  if (conn && conn->inner_conn) {
+    altcp_setprio(conn->inner_conn, prio);
+  }
+}
+
+void
+altcp_default_dealloc(struct altcp_pcb *conn)
+{
+  LWIP_UNUSED_ARG(conn);
+  /* nothing to do */
+}
+
+err_t
+altcp_default_get_tcp_addrinfo(struct altcp_pcb *conn, int local, ip_addr_t *addr, u16_t *port)
+{
+  if (conn && conn->inner_conn) {
+    return altcp_get_tcp_addrinfo(conn->inner_conn, local, addr, port);
+  }
+  return ERR_VAL;
+}
+
+ip_addr_t *
+altcp_default_get_ip(struct altcp_pcb *conn, int local)
+{
+  if (conn && conn->inner_conn) {
+    return altcp_get_ip(conn->inner_conn, local);
+  }
+  return NULL;
+}
+
+u16_t
+altcp_default_get_port(struct altcp_pcb *conn, int local)
+{
+  if (conn && conn->inner_conn) {
+    return altcp_get_port(conn->inner_conn, local);
+  }
+  return 0;
+}
+
+#if LWIP_TCP_KEEPALIVE
+void
+altcp_default_keepalive_disable(struct altcp_pcb *conn)
+{
+  if (conn && conn->inner_conn) {
+    altcp_keepalive_disable(conn->inner_conn);
+  }
+}
+
+void
+altcp_default_keepalive_enable(struct altcp_pcb *conn, u32_t idle, u32_t intvl, u32_t count)
+{
+  if (conn && conn->inner_conn) {
+      altcp_keepalive_enable(conn->inner_conn, idle, intvl, count);
+  }
+}
+#endif
+
+#ifdef LWIP_DEBUG
+enum tcp_state
+altcp_default_dbg_get_tcp_state(struct altcp_pcb *conn)
+{
+  if (conn && conn->inner_conn) {
+    return altcp_dbg_get_tcp_state(conn->inner_conn);
+  }
+  return CLOSED;
+}
+#endif
+
+
+#endif /* LWIP_ALTCP */

Drivers/LwIP/src/core/altcp_alloc.c

@@ -0,0 +1,87 @@
+/**
+ * @file
+ * Application layered TCP connection API (to be used from TCPIP thread)<br>
+ * This interface mimics the tcp callback API to the application while preventing
+ * direct linking (much like virtual functions).
+ * This way, an application can make use of other application layer protocols
+ * on top of TCP without knowing the details (e.g. TLS, proxy connection).
+ *
+ * This file contains allocation implementation that combine several layers.
+ */
+
+/*
+ * Copyright (c) 2017 Simon Goldschmidt
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Simon Goldschmidt <goldsimon@gmx.de>
+ *
+ */
+
+#include "lwip/opt.h"
+
+#if LWIP_ALTCP /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/altcp.h"
+#include "lwip/altcp_tcp.h"
+#include "lwip/altcp_tls.h"
+#include "lwip/priv/altcp_priv.h"
+#include "lwip/mem.h"
+
+#include <string.h>
+
+#if LWIP_ALTCP_TLS
+
+/** This standard allocator function creates an altcp pcb for
+ * TLS over TCP */
+struct altcp_pcb *
+altcp_tls_new(struct altcp_tls_config *config, u8_t ip_type)
+{
+  struct altcp_pcb *inner_conn, *ret;
+  LWIP_UNUSED_ARG(ip_type);
+
+  inner_conn = altcp_tcp_new_ip_type(ip_type);
+  if (inner_conn == NULL) {
+    return NULL;
+  }
+  ret = altcp_tls_wrap(config, inner_conn);
+  if (ret == NULL) {
+    altcp_close(inner_conn);
+  }
+  return ret;
+}
+
+/** This standard allocator function creates an altcp pcb for
+ * TLS over TCP */
+struct altcp_pcb *
+altcp_tls_alloc(void *arg, u8_t ip_type)
+{
+  return altcp_tls_new((struct altcp_tls_config *)arg, ip_type);
+}
+
+#endif /* LWIP_ALTCP_TLS */
+
+#endif /* LWIP_ALTCP */

Drivers/LwIP/src/core/altcp_tcp.c

@@ -0,0 +1,578 @@
+/**
+ * @file
+ * Application layered TCP connection API (to be used from TCPIP thread)
+ *
+ * This interface mimics the tcp callback API to the application while preventing
+ * direct linking (much like virtual functions).
+ * This way, an application can make use of other application layer protocols
+ * on top of TCP without knowing the details (e.g. TLS, proxy connection).
+ *
+ * This file contains the base implementation calling into tcp.
+ */
+
+/*
+ * Copyright (c) 2017 Simon Goldschmidt
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Simon Goldschmidt <goldsimon@gmx.de>
+ *
+ */
+
+#include "lwip/opt.h"
+
+#if LWIP_ALTCP /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/altcp.h"
+#include "lwip/altcp_tcp.h"
+#include "lwip/priv/altcp_priv.h"
+#include "lwip/tcp.h"
+#include "lwip/priv/tcp_priv.h"
+#include "lwip/mem.h"
+
+#include <string.h>
+
+#define ALTCP_TCP_ASSERT_CONN(conn) do { \
+  LWIP_ASSERT("conn->inner_conn == NULL", (conn)->inner_conn == NULL); \
+  LWIP_UNUSED_ARG(conn); /* for LWIP_NOASSERT */ } while(0)
+#define ALTCP_TCP_ASSERT_CONN_PCB(conn, tpcb) do { \
+  LWIP_ASSERT("pcb mismatch", (conn)->state == tpcb); \
+  LWIP_UNUSED_ARG(tpcb); /* for LWIP_NOASSERT */ \
+  ALTCP_TCP_ASSERT_CONN(conn); } while(0)
+
+
+/* Variable prototype, the actual declaration is at the end of this file
+   since it contains pointers to static functions declared here */
+extern const struct altcp_functions altcp_tcp_functions;
+
+static void altcp_tcp_setup(struct altcp_pcb *conn, struct tcp_pcb *tpcb);
+
+/* callback functions for TCP */
+static err_t
+altcp_tcp_accept(void *arg, struct tcp_pcb *new_tpcb, err_t err)
+{
+  struct altcp_pcb *listen_conn = (struct altcp_pcb *)arg;
+  if (new_tpcb && listen_conn && listen_conn->accept) {
+    /* create a new altcp_conn to pass to the next 'accept' callback */
+    struct altcp_pcb *new_conn = altcp_alloc();
+    if (new_conn == NULL) {
+      return ERR_MEM;
+    }
+    altcp_tcp_setup(new_conn, new_tpcb);
+    return listen_conn->accept(listen_conn->arg, new_conn, err);
+  }
+  return ERR_ARG;
+}
+
+static err_t
+altcp_tcp_connected(void *arg, struct tcp_pcb *tpcb, err_t err)
+{
+  struct altcp_pcb *conn = (struct altcp_pcb *)arg;
+  if (conn) {
+    ALTCP_TCP_ASSERT_CONN_PCB(conn, tpcb);
+    if (conn->connected) {
+      return conn->connected(conn->arg, conn, err);
+    }
+  }
+  return ERR_OK;
+}
+
+static err_t
+altcp_tcp_recv(void *arg, struct tcp_pcb *tpcb, struct pbuf *p, err_t err)
+{
+  struct altcp_pcb *conn = (struct altcp_pcb *)arg;
+  if (conn) {
+    ALTCP_TCP_ASSERT_CONN_PCB(conn, tpcb);
+    if (conn->recv) {
+      return conn->recv(conn->arg, conn, p, err);
+    }
+  }
+  if (p != NULL) {
+    /* prevent memory leaks */
+    pbuf_free(p);
+  }
+  return ERR_OK;
+}
+
+static err_t
+altcp_tcp_sent(void *arg, struct tcp_pcb *tpcb, u16_t len)
+{
+  struct altcp_pcb *conn = (struct altcp_pcb *)arg;
+  if (conn) {
+    ALTCP_TCP_ASSERT_CONN_PCB(conn, tpcb);
+    if (conn->sent) {
+      return conn->sent(conn->arg, conn, len);
+    }
+  }
+  return ERR_OK;
+}
+
+static err_t
+altcp_tcp_poll(void *arg, struct tcp_pcb *tpcb)
+{
+  struct altcp_pcb *conn = (struct altcp_pcb *)arg;
+  if (conn) {
+    ALTCP_TCP_ASSERT_CONN_PCB(conn, tpcb);
+    if (conn->poll) {
+      return conn->poll(conn->arg, conn);
+    }
+  }
+  return ERR_OK;
+}
+
+static void
+altcp_tcp_err(void *arg, err_t err)
+{
+  struct altcp_pcb *conn = (struct altcp_pcb *)arg;
+  if (conn) {
+    conn->state = NULL; /* already freed */
+    if (conn->err) {
+      conn->err(conn->arg, err);
+    }
+    altcp_free(conn);
+  }
+}
+
+/* setup functions */
+
+static void
+altcp_tcp_remove_callbacks(struct tcp_pcb *tpcb)
+{
+  tcp_arg(tpcb, NULL);
+  if (tpcb->state != LISTEN) {
+    tcp_recv(tpcb, NULL);
+    tcp_sent(tpcb, NULL);
+    tcp_err(tpcb, NULL);
+    tcp_poll(tpcb, NULL, tpcb->pollinterval);
+  }
+}
+
+static void
+altcp_tcp_setup_callbacks(struct altcp_pcb *conn, struct tcp_pcb *tpcb)
+{
+  tcp_arg(tpcb, conn);
+  /* this might be called for LISTN when close fails... */
+  if (tpcb->state != LISTEN) {
+    tcp_recv(tpcb, altcp_tcp_recv);
+    tcp_sent(tpcb, altcp_tcp_sent);
+    tcp_err(tpcb, altcp_tcp_err);
+    /* tcp_poll is set when interval is set by application */
+  }
+}
+
+static void
+altcp_tcp_setup(struct altcp_pcb *conn, struct tcp_pcb *tpcb)
+{
+  altcp_tcp_setup_callbacks(conn, tpcb);
+  conn->state = tpcb;
+  conn->fns = &altcp_tcp_functions;
+}
+
+struct altcp_pcb *
+altcp_tcp_new_ip_type(u8_t ip_type)
+{
+  /* Allocate the tcp pcb first to invoke the priority handling code
+     if we're out of pcbs */
+  struct tcp_pcb *tpcb = tcp_new_ip_type(ip_type);
+  if (tpcb != NULL) {
+    struct altcp_pcb *ret = altcp_alloc();
+    if (ret != NULL) {
+      altcp_tcp_setup(ret, tpcb);
+      return ret;
+    } else {
+      /* altcp_pcb allocation failed -> free the tcp_pcb too */
+      tcp_close(tpcb);
+    }
+  }
+  return NULL;
+}
+
+/** altcp_tcp allocator function fitting to @ref altcp_allocator_t / @ref altcp_new.
+*
+* arg pointer is not used for TCP.
+*/
+struct altcp_pcb *
+altcp_tcp_alloc(void *arg, u8_t ip_type)
+{
+  LWIP_UNUSED_ARG(arg);
+  return altcp_tcp_new_ip_type(ip_type);
+}
+
+struct altcp_pcb *
+altcp_tcp_wrap(struct tcp_pcb *tpcb)
+{
+  if (tpcb != NULL) {
+    struct altcp_pcb *ret = altcp_alloc();
+    if (ret != NULL) {
+      altcp_tcp_setup(ret, tpcb);
+      return ret;
+    }
+  }
+  return NULL;
+}
+
+
+/* "virtual" functions calling into tcp */
+static void
+altcp_tcp_set_poll(struct altcp_pcb *conn, u8_t interval)
+{
+  if (conn != NULL) {
+    struct tcp_pcb *pcb = (struct tcp_pcb *)conn->state;
+    ALTCP_TCP_ASSERT_CONN(conn);
+    tcp_poll(pcb, altcp_tcp_poll, interval);
+  }
+}
+
+static void
+altcp_tcp_recved(struct altcp_pcb *conn, u16_t len)
+{
+  if (conn != NULL) {
+    struct tcp_pcb *pcb = (struct tcp_pcb *)conn->state;
+    ALTCP_TCP_ASSERT_CONN(conn);
+    tcp_recved(pcb, len);
+  }
+}
+
+static err_t
+altcp_tcp_bind(struct altcp_pcb *conn, const ip_addr_t *ipaddr, u16_t port)
+{
+  struct tcp_pcb *pcb;
+  if (conn == NULL) {
+    return ERR_VAL;
+  }
+  ALTCP_TCP_ASSERT_CONN(conn);
+  pcb = (struct tcp_pcb *)conn->state;
+  return tcp_bind(pcb, ipaddr, port);
+}
+
+static err_t
+altcp_tcp_connect(struct altcp_pcb *conn, const ip_addr_t *ipaddr, u16_t port, altcp_connected_fn connected)
+{
+  struct tcp_pcb *pcb;
+  if (conn == NULL) {
+    return ERR_VAL;
+  }
+  ALTCP_TCP_ASSERT_CONN(conn);
+  conn->connected = connected;
+  pcb = (struct tcp_pcb *)conn->state;
+  return tcp_connect(pcb, ipaddr, port, altcp_tcp_connected);
+}
+
+static struct altcp_pcb *
+altcp_tcp_listen(struct altcp_pcb *conn, u8_t backlog, err_t *err)
+{
+  struct tcp_pcb *pcb;
+  struct tcp_pcb *lpcb;
+  if (conn == NULL) {
+    return NULL;
+  }
+  ALTCP_TCP_ASSERT_CONN(conn);
+  pcb = (struct tcp_pcb *)conn->state;
+  lpcb = tcp_listen_with_backlog_and_err(pcb, backlog, err);
+  if (lpcb != NULL) {
+    conn->state = lpcb;
+    tcp_accept(lpcb, altcp_tcp_accept);
+    return conn;
+  }
+  return NULL;
+}
+
+static void
+altcp_tcp_abort(struct altcp_pcb *conn)
+{
+  if (conn != NULL) {
+    struct tcp_pcb *pcb = (struct tcp_pcb *)conn->state;
+    ALTCP_TCP_ASSERT_CONN(conn);
+    if (pcb) {
+      tcp_abort(pcb);
+    }
+  }
+}
+
+static err_t
+altcp_tcp_close(struct altcp_pcb *conn)
+{
+  struct tcp_pcb *pcb;
+  if (conn == NULL) {
+    return ERR_VAL;
+  }
+  ALTCP_TCP_ASSERT_CONN(conn);
+  pcb = (struct tcp_pcb *)conn->state;
+  if (pcb) {
+    err_t err;
+    tcp_poll_fn oldpoll = pcb->poll;
+    altcp_tcp_remove_callbacks(pcb);
+    err = tcp_close(pcb);
+    if (err != ERR_OK) {
+      /* not closed, set up all callbacks again */
+      altcp_tcp_setup_callbacks(conn, pcb);
+      /* poll callback is not included in the above */
+      tcp_poll(pcb, oldpoll, pcb->pollinterval);
+      return err;
+    }
+    conn->state = NULL; /* unsafe to reference pcb after tcp_close(). */
+  }
+  altcp_free(conn);
+  return ERR_OK;
+}
+
+static err_t
+altcp_tcp_shutdown(struct altcp_pcb *conn, int shut_rx, int shut_tx)
+{
+  struct tcp_pcb *pcb;
+  if (conn == NULL) {
+    return ERR_VAL;
+  }
+  ALTCP_TCP_ASSERT_CONN(conn);
+  pcb = (struct tcp_pcb *)conn->state;
+  return tcp_shutdown(pcb, shut_rx, shut_tx);
+}
+
+static err_t
+altcp_tcp_write(struct altcp_pcb *conn, const void *dataptr, u16_t len, u8_t apiflags)
+{
+  struct tcp_pcb *pcb;
+  if (conn == NULL) {
+    return ERR_VAL;
+  }
+  ALTCP_TCP_ASSERT_CONN(conn);
+  pcb = (struct tcp_pcb *)conn->state;
+  return tcp_write(pcb, dataptr, len, apiflags);
+}
+
+static err_t
+altcp_tcp_output(struct altcp_pcb *conn)
+{
+  struct tcp_pcb *pcb;
+  if (conn == NULL) {
+    return ERR_VAL;
+  }
+  ALTCP_TCP_ASSERT_CONN(conn);
+  pcb = (struct tcp_pcb *)conn->state;
+  return tcp_output(pcb);
+}
+
+static u16_t
+altcp_tcp_mss(struct altcp_pcb *conn)
+{
+  struct tcp_pcb *pcb;
+  if (conn == NULL) {
+    return 0;
+  }
+  ALTCP_TCP_ASSERT_CONN(conn);
+  pcb = (struct tcp_pcb *)conn->state;
+  return tcp_mss(pcb);
+}
+
+static u16_t
+altcp_tcp_sndbuf(struct altcp_pcb *conn)
+{
+  struct tcp_pcb *pcb;
+  if (conn == NULL) {
+    return 0;
+  }
+  ALTCP_TCP_ASSERT_CONN(conn);
+  pcb = (struct tcp_pcb *)conn->state;
+  return tcp_sndbuf(pcb);
+}
+
+static u16_t
+altcp_tcp_sndqueuelen(struct altcp_pcb *conn)
+{
+  struct tcp_pcb *pcb;
+  if (conn == NULL) {
+    return 0;
+  }
+  ALTCP_TCP_ASSERT_CONN(conn);
+  pcb = (struct tcp_pcb *)conn->state;
+  return tcp_sndqueuelen(pcb);
+}
+
+static void
+altcp_tcp_nagle_disable(struct altcp_pcb *conn)
+{
+  if (conn && conn->state) {
+    struct tcp_pcb *pcb = (struct tcp_pcb *)conn->state;
+    ALTCP_TCP_ASSERT_CONN(conn);
+    tcp_nagle_disable(pcb);
+  }
+}
+
+static void
+altcp_tcp_nagle_enable(struct altcp_pcb *conn)
+{
+  if (conn && conn->state) {
+    struct tcp_pcb *pcb = (struct tcp_pcb *)conn->state;
+    ALTCP_TCP_ASSERT_CONN(conn);
+    tcp_nagle_enable(pcb);
+  }
+}
+
+static int
+altcp_tcp_nagle_disabled(struct altcp_pcb *conn)
+{
+  if (conn && conn->state) {
+    struct tcp_pcb *pcb = (struct tcp_pcb *)conn->state;
+    ALTCP_TCP_ASSERT_CONN(conn);
+    return tcp_nagle_disabled(pcb);
+  }
+  return 0;
+}
+
+static void
+altcp_tcp_setprio(struct altcp_pcb *conn, u8_t prio)
+{
+  if (conn != NULL) {
+    struct tcp_pcb *pcb = (struct tcp_pcb *)conn->state;
+    ALTCP_TCP_ASSERT_CONN(conn);
+    tcp_setprio(pcb, prio);
+  }
+}
+
+#if LWIP_TCP_KEEPALIVE
+static void
+altcp_tcp_keepalive_disable(struct altcp_pcb *conn)
+{
+  if (conn && conn->state) {
+    struct tcp_pcb *pcb = (struct tcp_pcb *)conn->state;
+    ALTCP_TCP_ASSERT_CONN(conn);
+    ip_reset_option(pcb, SOF_KEEPALIVE);
+  }
+}
+
+static void
+altcp_tcp_keepalive_enable(struct altcp_pcb *conn, u32_t idle, u32_t intvl, u32_t cnt)
+{
+  if (conn && conn->state) {
+    struct tcp_pcb *pcb = (struct tcp_pcb *)conn->state;
+    ALTCP_TCP_ASSERT_CONN(conn);
+    ip_set_option(pcb, SOF_KEEPALIVE);
+    pcb->keep_idle = idle ? idle : TCP_KEEPIDLE_DEFAULT;
+    pcb->keep_intvl = intvl ? intvl : TCP_KEEPINTVL_DEFAULT;
+    pcb->keep_cnt = cnt ? cnt : TCP_KEEPCNT_DEFAULT;
+  }
+}
+#endif
+
+static void
+altcp_tcp_dealloc(struct altcp_pcb *conn)
+{
+  LWIP_UNUSED_ARG(conn);
+  ALTCP_TCP_ASSERT_CONN(conn);
+  /* no private state to clean up */
+}
+
+static err_t
+altcp_tcp_get_tcp_addrinfo(struct altcp_pcb *conn, int local, ip_addr_t *addr, u16_t *port)
+{
+  if (conn) {
+    struct tcp_pcb *pcb = (struct tcp_pcb *)conn->state;
+    ALTCP_TCP_ASSERT_CONN(conn);
+    return tcp_tcp_get_tcp_addrinfo(pcb, local, addr, port);
+  }
+  return ERR_VAL;
+}
+
+static ip_addr_t *
+altcp_tcp_get_ip(struct altcp_pcb *conn, int local)
+{
+  if (conn) {
+    struct tcp_pcb *pcb = (struct tcp_pcb *)conn->state;
+    ALTCP_TCP_ASSERT_CONN(conn);
+    if (pcb) {
+      if (local) {
+        return &pcb->local_ip;
+      } else {
+        return &pcb->remote_ip;
+      }
+    }
+  }
+  return NULL;
+}
+
+static u16_t
+altcp_tcp_get_port(struct altcp_pcb *conn, int local)
+{
+  if (conn) {
+    struct tcp_pcb *pcb = (struct tcp_pcb *)conn->state;
+    ALTCP_TCP_ASSERT_CONN(conn);
+    if (pcb) {
+      if (local) {
+        return pcb->local_port;
+      } else {
+        return pcb->remote_port;
+      }
+    }
+  }
+  return 0;
+}
+
+#ifdef LWIP_DEBUG
+static enum tcp_state
+altcp_tcp_dbg_get_tcp_state(struct altcp_pcb *conn)
+{
+  if (conn) {
+    struct tcp_pcb *pcb = (struct tcp_pcb *)conn->state;
+    ALTCP_TCP_ASSERT_CONN(conn);
+    if (pcb) {
+      return pcb->state;
+    }
+  }
+  return CLOSED;
+}
+#endif
+const struct altcp_functions altcp_tcp_functions = {
+  altcp_tcp_set_poll,
+  altcp_tcp_recved,
+  altcp_tcp_bind,
+  altcp_tcp_connect,
+  altcp_tcp_listen,
+  altcp_tcp_abort,
+  altcp_tcp_close,
+  altcp_tcp_shutdown,
+  altcp_tcp_write,
+  altcp_tcp_output,
+  altcp_tcp_mss,
+  altcp_tcp_sndbuf,
+  altcp_tcp_sndqueuelen,
+  altcp_tcp_nagle_disable,
+  altcp_tcp_nagle_enable,
+  altcp_tcp_nagle_disabled,
+  altcp_tcp_setprio,
+  altcp_tcp_dealloc,
+  altcp_tcp_get_tcp_addrinfo,
+  altcp_tcp_get_ip,
+  altcp_tcp_get_port
+#if LWIP_TCP_KEEPALIVE
+  , altcp_tcp_keepalive_disable
+  , altcp_tcp_keepalive_enable
+#endif
+#ifdef LWIP_DEBUG
+  , altcp_tcp_dbg_get_tcp_state
+#endif
+};
+
+#endif /* LWIP_ALTCP */

Drivers/LwIP/src/core/def.c

@@ -0,0 +1,263 @@
+/**
+ * @file
+ * Common functions used throughout the stack.
+ *
+ * These are reference implementations of the byte swapping functions.
+ * Again with the aim of being simple, correct and fully portable.
+ * Byte swapping is the second thing you would want to optimize. You will
+ * need to port it to your architecture and in your cc.h:
+ *
+ * \#define lwip_htons(x) your_htons
+ * \#define lwip_htonl(x) your_htonl
+ *
+ * Note lwip_ntohs() and lwip_ntohl() are merely references to the htonx counterparts.
+ *
+ * If you \#define them to htons() and htonl(), you should
+ * \#define LWIP_DONT_PROVIDE_BYTEORDER_FUNCTIONS to prevent lwIP from
+ * defining htonx/ntohx compatibility macros.
+
+ * @defgroup sys_nonstandard Non-standard functions
+ * @ingroup sys_layer
+ * lwIP provides default implementations for non-standard functions.
+ * These can be mapped to OS functions to reduce code footprint if desired.
+ * All defines related to this section must not be placed in lwipopts.h,
+ * but in arch/cc.h!
+ * These options cannot be \#defined in lwipopts.h since they are not options
+ * of lwIP itself, but options of the lwIP port to your system.
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Simon Goldschmidt
+ *
+ */
+
+#include "lwip/opt.h"
+#include "lwip/def.h"
+
+#include <string.h>
+
+#if BYTE_ORDER == LITTLE_ENDIAN
+
+#if !defined(lwip_htons)
+/**
+ * Convert an u16_t from host- to network byte order.
+ *
+ * @param n u16_t in host byte order
+ * @return n in network byte order
+ */
+u16_t
+lwip_htons(u16_t n)
+{
+  return PP_HTONS(n);
+}
+#endif /* lwip_htons */
+
+#if !defined(lwip_htonl)
+/**
+ * Convert an u32_t from host- to network byte order.
+ *
+ * @param n u32_t in host byte order
+ * @return n in network byte order
+ */
+u32_t
+lwip_htonl(u32_t n)
+{
+  return PP_HTONL(n);
+}
+#endif /* lwip_htonl */
+
+#endif /* BYTE_ORDER == LITTLE_ENDIAN */
+
+#ifndef lwip_strnstr
+/**
+ * @ingroup sys_nonstandard
+ * lwIP default implementation for strnstr() non-standard function.
+ * This can be \#defined to strnstr() depending on your platform port.
+ */
+char *
+lwip_strnstr(const char *buffer, const char *token, size_t n)
+{
+  const char *p;
+  size_t tokenlen = strlen(token);
+  if (tokenlen == 0) {
+    return LWIP_CONST_CAST(char *, buffer);
+  }
+  for (p = buffer; *p && (p + tokenlen <= buffer + n); p++) {
+    if ((*p == *token) && (strncmp(p, token, tokenlen) == 0)) {
+      return LWIP_CONST_CAST(char *, p);
+    }
+  }
+  return NULL;
+}
+#endif
+
+#ifndef lwip_strnistr
+/**
+ * @ingroup sys_nonstandard
+ * lwIP default implementation for strnistr() non-standard function.
+ * This can be \#defined to strnistr() depending on your platform port.
+ */
+char *
+lwip_strnistr(const char *buffer, const char *token, size_t n)
+{
+  const char *p;
+  size_t tokenlen = strlen(token);
+  if (tokenlen == 0) {
+    return LWIP_CONST_CAST(char *, buffer);
+  }
+  for (p = buffer; *p && (p + tokenlen <= buffer + n); p++) {
+    if (lwip_strnicmp(p, token, tokenlen) == 0) {
+      return LWIP_CONST_CAST(char *, p);
+    }
+  }
+  return NULL;
+}
+#endif
+
+#ifndef lwip_stricmp
+/**
+ * @ingroup sys_nonstandard
+ * lwIP default implementation for stricmp() non-standard function.
+ * This can be \#defined to stricmp() depending on your platform port.
+ */
+int
+lwip_stricmp(const char *str1, const char *str2)
+{
+  char c1, c2;
+
+  do {
+    c1 = *str1++;
+    c2 = *str2++;
+    if (c1 != c2) {
+      char c1_upc = c1 | 0x20;
+      if ((c1_upc >= 'a') && (c1_upc <= 'z')) {
+        /* characters are not equal an one is in the alphabet range:
+        downcase both chars and check again */
+        char c2_upc = c2 | 0x20;
+        if (c1_upc != c2_upc) {
+          /* still not equal */
+          /* don't care for < or > */
+          return 1;
+        }
+      } else {
+        /* characters are not equal but none is in the alphabet range */
+        return 1;
+      }
+    }
+  } while (c1 != 0);
+  return 0;
+}
+#endif
+
+#ifndef lwip_strnicmp
+/**
+ * @ingroup sys_nonstandard
+ * lwIP default implementation for strnicmp() non-standard function.
+ * This can be \#defined to strnicmp() depending on your platform port.
+ */
+int
+lwip_strnicmp(const char *str1, const char *str2, size_t len)
+{
+  char c1, c2;
+
+  do {
+    c1 = *str1++;
+    c2 = *str2++;
+    if (c1 != c2) {
+      char c1_upc = c1 | 0x20;
+      if ((c1_upc >= 'a') && (c1_upc <= 'z')) {
+        /* characters are not equal an one is in the alphabet range:
+        downcase both chars and check again */
+        char c2_upc = c2 | 0x20;
+        if (c1_upc != c2_upc) {
+          /* still not equal */
+          /* don't care for < or > */
+          return 1;
+        }
+      } else {
+        /* characters are not equal but none is in the alphabet range */
+        return 1;
+      }
+    }
+    len--;
+  } while ((len != 0) && (c1 != 0));
+  return 0;
+}
+#endif
+
+#ifndef lwip_itoa
+/**
+ * @ingroup sys_nonstandard
+ * lwIP default implementation for itoa() non-standard function.
+ * This can be \#defined to itoa() or snprintf(result, bufsize, "%d", number) depending on your platform port.
+ */
+void
+lwip_itoa(char *result, size_t bufsize, int number)
+{
+  char *res = result;
+  char *tmp = result + bufsize - 1;
+  int n = (number >= 0) ? number : -number;
+
+  /* handle invalid bufsize */
+  if (bufsize < 2) {
+    if (bufsize == 1) {
+      *result = 0;
+    }
+    return;
+  }
+
+  /* First, add sign */
+  if (number < 0) {
+    *res++ = '-';
+  }
+  /* Then create the string from the end and stop if buffer full,
+     and ensure output string is zero terminated */
+  *tmp = 0;
+  while ((n != 0) && (tmp > res)) {
+    char val = (char)('0' + (n % 10));
+    tmp--;
+    *tmp = val;
+    n = n / 10;
+  }
+  if (n) {
+    /* buffer is too small */
+    *result = 0;
+    return;
+  }
+  if (*tmp == 0) {
+    /* Nothing added? */
+    *res++ = '0';
+    *res++ = 0;
+    return;
+  }
+  /* move from temporary buffer to output buffer (sign is not moved) */
+  memmove(res, tmp, (size_t)((result + bufsize) - tmp));
+}
+#endif

Drivers/LwIP/src/core/inet_chksum.c

@@ -0,0 +1,608 @@
+/**
+ * @file
+ * Internet checksum functions.
+ *
+ * These are some reference implementations of the checksum algorithm, with the
+ * aim of being simple, correct and fully portable. Checksumming is the
+ * first thing you would want to optimize for your platform. If you create
+ * your own version, link it in and in your cc.h put:
+ *
+ * \#define LWIP_CHKSUM your_checksum_routine
+ *
+ * Or you can select from the implementations below by defining
+ * LWIP_CHKSUM_ALGORITHM to 1, 2 or 3.
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+
+#include "lwip/opt.h"
+
+#include "lwip/inet_chksum.h"
+#include "lwip/def.h"
+#include "lwip/ip_addr.h"
+
+#include <string.h>
+
+#ifndef LWIP_CHKSUM
+# define LWIP_CHKSUM lwip_standard_chksum
+# ifndef LWIP_CHKSUM_ALGORITHM
+#  define LWIP_CHKSUM_ALGORITHM 2
+# endif
+u16_t lwip_standard_chksum(const void *dataptr, int len);
+#endif
+/* If none set: */
+#ifndef LWIP_CHKSUM_ALGORITHM
+# define LWIP_CHKSUM_ALGORITHM 0
+#endif
+
+#if (LWIP_CHKSUM_ALGORITHM == 1) /* Version #1 */
+/**
+ * lwip checksum
+ *
+ * @param dataptr points to start of data to be summed at any boundary
+ * @param len length of data to be summed
+ * @return host order (!) lwip checksum (non-inverted Internet sum)
+ *
+ * @note accumulator size limits summable length to 64k
+ * @note host endianness is irrelevant (p3 RFC1071)
+ */
+u16_t
+lwip_standard_chksum(const void *dataptr, int len)
+{
+  u32_t acc;
+  u16_t src;
+  const u8_t *octetptr;
+
+  acc = 0;
+  /* dataptr may be at odd or even addresses */
+  octetptr = (const u8_t *)dataptr;
+  while (len > 1) {
+    /* declare first octet as most significant
+       thus assume network order, ignoring host order */
+    src = (*octetptr) << 8;
+    octetptr++;
+    /* declare second octet as least significant */
+    src |= (*octetptr);
+    octetptr++;
+    acc += src;
+    len -= 2;
+  }
+  if (len > 0) {
+    /* accumulate remaining octet */
+    src = (*octetptr) << 8;
+    acc += src;
+  }
+  /* add deferred carry bits */
+  acc = (acc >> 16) + (acc & 0x0000ffffUL);
+  if ((acc & 0xffff0000UL) != 0) {
+    acc = (acc >> 16) + (acc & 0x0000ffffUL);
+  }
+  /* This maybe a little confusing: reorder sum using lwip_htons()
+     instead of lwip_ntohs() since it has a little less call overhead.
+     The caller must invert bits for Internet sum ! */
+  return lwip_htons((u16_t)acc);
+}
+#endif
+
+#if (LWIP_CHKSUM_ALGORITHM == 2) /* Alternative version #2 */
+/*
+ * Curt McDowell
+ * Broadcom Corp.
+ * csm@broadcom.com
+ *
+ * IP checksum two bytes at a time with support for
+ * unaligned buffer.
+ * Works for len up to and including 0x20000.
+ * by Curt McDowell, Broadcom Corp. 12/08/2005
+ *
+ * @param dataptr points to start of data to be summed at any boundary
+ * @param len length of data to be summed
+ * @return host order (!) lwip checksum (non-inverted Internet sum)
+ */
+u16_t
+lwip_standard_chksum(const void *dataptr, int len)
+{
+  const u8_t *pb = (const u8_t *)dataptr;
+  const u16_t *ps;
+  u16_t t = 0;
+  u32_t sum = 0;
+  int odd = ((mem_ptr_t)pb & 1);
+
+  /* Get aligned to u16_t */
+  if (odd && len > 0) {
+    ((u8_t *)&t)[1] = *pb++;
+    len--;
+  }
+
+  /* Add the bulk of the data */
+  ps = (const u16_t *)(const void *)pb;
+  while (len > 1) {
+    sum += *ps++;
+    len -= 2;
+  }
+
+  /* Consume left-over byte, if any */
+  if (len > 0) {
+    ((u8_t *)&t)[0] = *(const u8_t *)ps;
+  }
+
+  /* Add end bytes */
+  sum += t;
+
+  /* Fold 32-bit sum to 16 bits
+     calling this twice is probably faster than if statements... */
+  sum = FOLD_U32T(sum);
+  sum = FOLD_U32T(sum);
+
+  /* Swap if alignment was odd */
+  if (odd) {
+    sum = SWAP_BYTES_IN_WORD(sum);
+  }
+
+  return (u16_t)sum;
+}
+#endif
+
+#if (LWIP_CHKSUM_ALGORITHM == 3) /* Alternative version #3 */
+/**
+ * An optimized checksum routine. Basically, it uses loop-unrolling on
+ * the checksum loop, treating the head and tail bytes specially, whereas
+ * the inner loop acts on 8 bytes at a time.
+ *
+ * @arg start of buffer to be checksummed. May be an odd byte address.
+ * @len number of bytes in the buffer to be checksummed.
+ * @return host order (!) lwip checksum (non-inverted Internet sum)
+ *
+ * by Curt McDowell, Broadcom Corp. December 8th, 2005
+ */
+u16_t
+lwip_standard_chksum(const void *dataptr, int len)
+{
+  const u8_t *pb = (const u8_t *)dataptr;
+  const u16_t *ps;
+  u16_t t = 0;
+  const u32_t *pl;
+  u32_t sum = 0, tmp;
+  /* starts at odd byte address? */
+  int odd = ((mem_ptr_t)pb & 1);
+
+  if (odd && len > 0) {
+    ((u8_t *)&t)[1] = *pb++;
+    len--;
+  }
+
+  ps = (const u16_t *)(const void *)pb;
+
+  if (((mem_ptr_t)ps & 3) && len > 1) {
+    sum += *ps++;
+    len -= 2;
+  }
+
+  pl = (const u32_t *)(const void *)ps;
+
+  while (len > 7)  {
+    tmp = sum + *pl++;          /* ping */
+    if (tmp < sum) {
+      tmp++;                    /* add back carry */
+    }
+
+    sum = tmp + *pl++;          /* pong */
+    if (sum < tmp) {
+      sum++;                    /* add back carry */
+    }
+
+    len -= 8;
+  }
+
+  /* make room in upper bits */
+  sum = FOLD_U32T(sum);
+
+  ps = (const u16_t *)pl;
+
+  /* 16-bit aligned word remaining? */
+  while (len > 1) {
+    sum += *ps++;
+    len -= 2;
+  }
+
+  /* dangling tail byte remaining? */
+  if (len > 0) {                /* include odd byte */
+    ((u8_t *)&t)[0] = *(const u8_t *)ps;
+  }
+
+  sum += t;                     /* add end bytes */
+
+  /* Fold 32-bit sum to 16 bits
+     calling this twice is probably faster than if statements... */
+  sum = FOLD_U32T(sum);
+  sum = FOLD_U32T(sum);
+
+  if (odd) {
+    sum = SWAP_BYTES_IN_WORD(sum);
+  }
+
+  return (u16_t)sum;
+}
+#endif
+
+/** Parts of the pseudo checksum which are common to IPv4 and IPv6 */
+static u16_t
+inet_cksum_pseudo_base(struct pbuf *p, u8_t proto, u16_t proto_len, u32_t acc)
+{
+  struct pbuf *q;
+  int swapped = 0;
+
+  /* iterate through all pbuf in chain */
+  for (q = p; q != NULL; q = q->next) {
+    LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): checksumming pbuf %p (has next %p) \n",
+                             (void *)q, (void *)q->next));
+    acc += LWIP_CHKSUM(q->payload, q->len);
+    /*LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): unwrapped lwip_chksum()=%"X32_F" \n", acc));*/
+    /* just executing this next line is probably faster that the if statement needed
+       to check whether we really need to execute it, and does no harm */
+    acc = FOLD_U32T(acc);
+    if (q->len % 2 != 0) {
+      swapped = !swapped;
+      acc = SWAP_BYTES_IN_WORD(acc);
+    }
+    /*LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): wrapped lwip_chksum()=%"X32_F" \n", acc));*/
+  }
+
+  if (swapped) {
+    acc = SWAP_BYTES_IN_WORD(acc);
+  }
+
+  acc += (u32_t)lwip_htons((u16_t)proto);
+  acc += (u32_t)lwip_htons(proto_len);
+
+  /* Fold 32-bit sum to 16 bits
+     calling this twice is probably faster than if statements... */
+  acc = FOLD_U32T(acc);
+  acc = FOLD_U32T(acc);
+  LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): pbuf chain lwip_chksum()=%"X32_F"\n", acc));
+  return (u16_t)~(acc & 0xffffUL);
+}
+
+#if LWIP_IPV4
+/* inet_chksum_pseudo:
+ *
+ * Calculates the IPv4 pseudo Internet checksum used by TCP and UDP for a pbuf chain.
+ * IP addresses are expected to be in network byte order.
+ *
+ * @param p chain of pbufs over that a checksum should be calculated (ip data part)
+ * @param src source ip address (used for checksum of pseudo header)
+ * @param dst destination ip address (used for checksum of pseudo header)
+ * @param proto ip protocol (used for checksum of pseudo header)
+ * @param proto_len length of the ip data part (used for checksum of pseudo header)
+ * @return checksum (as u16_t) to be saved directly in the protocol header
+ */
+u16_t
+inet_chksum_pseudo(struct pbuf *p, u8_t proto, u16_t proto_len,
+                   const ip4_addr_t *src, const ip4_addr_t *dest)
+{
+  u32_t acc;
+  u32_t addr;
+
+  addr = ip4_addr_get_u32(src);
+  acc = (addr & 0xffffUL);
+  acc = (u32_t)(acc + ((addr >> 16) & 0xffffUL));
+  addr = ip4_addr_get_u32(dest);
+  acc = (u32_t)(acc + (addr & 0xffffUL));
+  acc = (u32_t)(acc + ((addr >> 16) & 0xffffUL));
+  /* fold down to 16 bits */
+  acc = FOLD_U32T(acc);
+  acc = FOLD_U32T(acc);
+
+  return inet_cksum_pseudo_base(p, proto, proto_len, acc);
+}
+#endif /* LWIP_IPV4 */
+
+#if LWIP_IPV6
+/**
+ * Calculates the checksum with IPv6 pseudo header used by TCP and UDP for a pbuf chain.
+ * IPv6 addresses are expected to be in network byte order.
+ *
+ * @param p chain of pbufs over that a checksum should be calculated (ip data part)
+ * @param proto ipv6 protocol/next header (used for checksum of pseudo header)
+ * @param proto_len length of the ipv6 payload (used for checksum of pseudo header)
+ * @param src source ipv6 address (used for checksum of pseudo header)
+ * @param dest destination ipv6 address (used for checksum of pseudo header)
+ * @return checksum (as u16_t) to be saved directly in the protocol header
+ */
+u16_t
+ip6_chksum_pseudo(struct pbuf *p, u8_t proto, u16_t proto_len,
+                  const ip6_addr_t *src, const ip6_addr_t *dest)
+{
+  u32_t acc = 0;
+  u32_t addr;
+  u8_t addr_part;
+
+  for (addr_part = 0; addr_part < 4; addr_part++) {
+    addr = src->addr[addr_part];
+    acc = (u32_t)(acc + (addr & 0xffffUL));
+    acc = (u32_t)(acc + ((addr >> 16) & 0xffffUL));
+    addr = dest->addr[addr_part];
+    acc = (u32_t)(acc + (addr & 0xffffUL));
+    acc = (u32_t)(acc + ((addr >> 16) & 0xffffUL));
+  }
+  /* fold down to 16 bits */
+  acc = FOLD_U32T(acc);
+  acc = FOLD_U32T(acc);
+
+  return inet_cksum_pseudo_base(p, proto, proto_len, acc);
+}
+#endif /* LWIP_IPV6 */
+
+/* ip_chksum_pseudo:
+ *
+ * Calculates the IPv4 or IPv6 pseudo Internet checksum used by TCP and UDP for a pbuf chain.
+ * IP addresses are expected to be in network byte order.
+ *
+ * @param p chain of pbufs over that a checksum should be calculated (ip data part)
+ * @param src source ip address (used for checksum of pseudo header)
+ * @param dst destination ip address (used for checksum of pseudo header)
+ * @param proto ip protocol (used for checksum of pseudo header)
+ * @param proto_len length of the ip data part (used for checksum of pseudo header)
+ * @return checksum (as u16_t) to be saved directly in the protocol header
+ */
+u16_t
+ip_chksum_pseudo(struct pbuf *p, u8_t proto, u16_t proto_len,
+                 const ip_addr_t *src, const ip_addr_t *dest)
+{
+#if LWIP_IPV6
+  if (IP_IS_V6(dest)) {
+    return ip6_chksum_pseudo(p, proto, proto_len, ip_2_ip6(src), ip_2_ip6(dest));
+  }
+#endif /* LWIP_IPV6 */
+#if LWIP_IPV4 && LWIP_IPV6
+  else
+#endif /* LWIP_IPV4 && LWIP_IPV6 */
+#if LWIP_IPV4
+  {
+    return inet_chksum_pseudo(p, proto, proto_len, ip_2_ip4(src), ip_2_ip4(dest));
+  }
+#endif /* LWIP_IPV4 */
+}
+
+/** Parts of the pseudo checksum which are common to IPv4 and IPv6 */
+static u16_t
+inet_cksum_pseudo_partial_base(struct pbuf *p, u8_t proto, u16_t proto_len,
+                               u16_t chksum_len, u32_t acc)
+{
+  struct pbuf *q;
+  int swapped = 0;
+  u16_t chklen;
+
+  /* iterate through all pbuf in chain */
+  for (q = p; (q != NULL) && (chksum_len > 0); q = q->next) {
+    LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): checksumming pbuf %p (has next %p) \n",
+                             (void *)q, (void *)q->next));
+    chklen = q->len;
+    if (chklen > chksum_len) {
+      chklen = chksum_len;
+    }
+    acc += LWIP_CHKSUM(q->payload, chklen);
+    chksum_len = (u16_t)(chksum_len - chklen);
+    LWIP_ASSERT("delete me", chksum_len < 0x7fff);
+    /*LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): unwrapped lwip_chksum()=%"X32_F" \n", acc));*/
+    /* fold the upper bit down */
+    acc = FOLD_U32T(acc);
+    if (q->len % 2 != 0) {
+      swapped = !swapped;
+      acc = SWAP_BYTES_IN_WORD(acc);
+    }
+    /*LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): wrapped lwip_chksum()=%"X32_F" \n", acc));*/
+  }
+
+  if (swapped) {
+    acc = SWAP_BYTES_IN_WORD(acc);
+  }
+
+  acc += (u32_t)lwip_htons((u16_t)proto);
+  acc += (u32_t)lwip_htons(proto_len);
+
+  /* Fold 32-bit sum to 16 bits
+     calling this twice is probably faster than if statements... */
+  acc = FOLD_U32T(acc);
+  acc = FOLD_U32T(acc);
+  LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): pbuf chain lwip_chksum()=%"X32_F"\n", acc));
+  return (u16_t)~(acc & 0xffffUL);
+}
+
+#if LWIP_IPV4
+/* inet_chksum_pseudo_partial:
+ *
+ * Calculates the IPv4 pseudo Internet checksum used by TCP and UDP for a pbuf chain.
+ * IP addresses are expected to be in network byte order.
+ *
+ * @param p chain of pbufs over that a checksum should be calculated (ip data part)
+ * @param src source ip address (used for checksum of pseudo header)
+ * @param dst destination ip address (used for checksum of pseudo header)
+ * @param proto ip protocol (used for checksum of pseudo header)
+ * @param proto_len length of the ip data part (used for checksum of pseudo header)
+ * @return checksum (as u16_t) to be saved directly in the protocol header
+ */
+u16_t
+inet_chksum_pseudo_partial(struct pbuf *p, u8_t proto, u16_t proto_len,
+                           u16_t chksum_len, const ip4_addr_t *src, const ip4_addr_t *dest)
+{
+  u32_t acc;
+  u32_t addr;
+
+  addr = ip4_addr_get_u32(src);
+  acc = (addr & 0xffffUL);
+  acc = (u32_t)(acc + ((addr >> 16) & 0xffffUL));
+  addr = ip4_addr_get_u32(dest);
+  acc = (u32_t)(acc + (addr & 0xffffUL));
+  acc = (u32_t)(acc + ((addr >> 16) & 0xffffUL));
+  /* fold down to 16 bits */
+  acc = FOLD_U32T(acc);
+  acc = FOLD_U32T(acc);
+
+  return inet_cksum_pseudo_partial_base(p, proto, proto_len, chksum_len, acc);
+}
+#endif /* LWIP_IPV4 */
+
+#if LWIP_IPV6
+/**
+ * Calculates the checksum with IPv6 pseudo header used by TCP and UDP for a pbuf chain.
+ * IPv6 addresses are expected to be in network byte order. Will only compute for a
+ * portion of the payload.
+ *
+ * @param p chain of pbufs over that a checksum should be calculated (ip data part)
+ * @param proto ipv6 protocol/next header (used for checksum of pseudo header)
+ * @param proto_len length of the ipv6 payload (used for checksum of pseudo header)
+ * @param chksum_len number of payload bytes used to compute chksum
+ * @param src source ipv6 address (used for checksum of pseudo header)
+ * @param dest destination ipv6 address (used for checksum of pseudo header)
+ * @return checksum (as u16_t) to be saved directly in the protocol header
+ */
+u16_t
+ip6_chksum_pseudo_partial(struct pbuf *p, u8_t proto, u16_t proto_len,
+                          u16_t chksum_len, const ip6_addr_t *src, const ip6_addr_t *dest)
+{
+  u32_t acc = 0;
+  u32_t addr;
+  u8_t addr_part;
+
+  for (addr_part = 0; addr_part < 4; addr_part++) {
+    addr = src->addr[addr_part];
+    acc = (u32_t)(acc + (addr & 0xffffUL));
+    acc = (u32_t)(acc + ((addr >> 16) & 0xffffUL));
+    addr = dest->addr[addr_part];
+    acc = (u32_t)(acc + (addr & 0xffffUL));
+    acc = (u32_t)(acc + ((addr >> 16) & 0xffffUL));
+  }
+  /* fold down to 16 bits */
+  acc = FOLD_U32T(acc);
+  acc = FOLD_U32T(acc);
+
+  return inet_cksum_pseudo_partial_base(p, proto, proto_len, chksum_len, acc);
+}
+#endif /* LWIP_IPV6 */
+
+/* ip_chksum_pseudo_partial:
+ *
+ * Calculates the IPv4 or IPv6 pseudo Internet checksum used by TCP and UDP for a pbuf chain.
+ *
+ * @param p chain of pbufs over that a checksum should be calculated (ip data part)
+ * @param src source ip address (used for checksum of pseudo header)
+ * @param dst destination ip address (used for checksum of pseudo header)
+ * @param proto ip protocol (used for checksum of pseudo header)
+ * @param proto_len length of the ip data part (used for checksum of pseudo header)
+ * @return checksum (as u16_t) to be saved directly in the protocol header
+ */
+u16_t
+ip_chksum_pseudo_partial(struct pbuf *p, u8_t proto, u16_t proto_len,
+                         u16_t chksum_len, const ip_addr_t *src, const ip_addr_t *dest)
+{
+#if LWIP_IPV6
+  if (IP_IS_V6(dest)) {
+    return ip6_chksum_pseudo_partial(p, proto, proto_len, chksum_len, ip_2_ip6(src), ip_2_ip6(dest));
+  }
+#endif /* LWIP_IPV6 */
+#if LWIP_IPV4 && LWIP_IPV6
+  else
+#endif /* LWIP_IPV4 && LWIP_IPV6 */
+#if LWIP_IPV4
+  {
+    return inet_chksum_pseudo_partial(p, proto, proto_len, chksum_len, ip_2_ip4(src), ip_2_ip4(dest));
+  }
+#endif /* LWIP_IPV4 */
+}
+
+/* inet_chksum:
+ *
+ * Calculates the Internet checksum over a portion of memory. Used primarily for IP
+ * and ICMP.
+ *
+ * @param dataptr start of the buffer to calculate the checksum (no alignment needed)
+ * @param len length of the buffer to calculate the checksum
+ * @return checksum (as u16_t) to be saved directly in the protocol header
+ */
+
+u16_t
+inet_chksum(const void *dataptr, u16_t len)
+{
+  return (u16_t)~(unsigned int)LWIP_CHKSUM(dataptr, len);
+}
+
+/**
+ * Calculate a checksum over a chain of pbufs (without pseudo-header, much like
+ * inet_chksum only pbufs are used).
+ *
+ * @param p pbuf chain over that the checksum should be calculated
+ * @return checksum (as u16_t) to be saved directly in the protocol header
+ */
+u16_t
+inet_chksum_pbuf(struct pbuf *p)
+{
+  u32_t acc;
+  struct pbuf *q;
+  int swapped = 0;
+
+  acc = 0;
+  for (q = p; q != NULL; q = q->next) {
+    acc += LWIP_CHKSUM(q->payload, q->len);
+    acc = FOLD_U32T(acc);
+    if (q->len % 2 != 0) {
+      swapped = !swapped;
+      acc = SWAP_BYTES_IN_WORD(acc);
+    }
+  }
+
+  if (swapped) {
+    acc = SWAP_BYTES_IN_WORD(acc);
+  }
+  return (u16_t)~(acc & 0xffffUL);
+}
+
+/* These are some implementations for LWIP_CHKSUM_COPY, which copies data
+ * like MEMCPY but generates a checksum at the same time. Since this is a
+ * performance-sensitive function, you might want to create your own version
+ * in assembly targeted at your hardware by defining it in lwipopts.h:
+ *   #define LWIP_CHKSUM_COPY(dst, src, len) your_chksum_copy(dst, src, len)
+ */
+
+#if (LWIP_CHKSUM_COPY_ALGORITHM == 1) /* Version #1 */
+/** Safe but slow: first call MEMCPY, then call LWIP_CHKSUM.
+ * For architectures with big caches, data might still be in cache when
+ * generating the checksum after copying.
+ */
+u16_t
+lwip_chksum_copy(void *dst, const void *src, u16_t len)
+{
+  MEMCPY(dst, src, len);
+  return LWIP_CHKSUM(dst, len);
+}
+#endif /* (LWIP_CHKSUM_COPY_ALGORITHM == 1) */

Drivers/LwIP/src/core/init.c

@@ -0,0 +1,387 @@
+/**
+ * @file
+ * Modules initialization
+ *
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Adam Dunkels <adam@sics.se>
+ */
+
+#include "lwip/opt.h"
+
+#include "lwip/init.h"
+#include "lwip/stats.h"
+#include "lwip/sys.h"
+#include "lwip/mem.h"
+#include "lwip/memp.h"
+#include "lwip/pbuf.h"
+#include "lwip/netif.h"
+#include "lwip/sockets.h"
+#include "lwip/ip.h"
+#include "lwip/raw.h"
+#include "lwip/udp.h"
+#include "lwip/priv/tcp_priv.h"
+#include "lwip/igmp.h"
+#include "lwip/dns.h"
+#include "lwip/timeouts.h"
+#include "lwip/etharp.h"
+#include "lwip/ip6.h"
+#include "lwip/nd6.h"
+#include "lwip/mld6.h"
+#include "lwip/api.h"
+
+#include "netif/ppp/ppp_opts.h"
+#include "netif/ppp/ppp_impl.h"
+
+#ifndef LWIP_SKIP_PACKING_CHECK
+
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/bpstruct.h"
+#endif
+PACK_STRUCT_BEGIN
+struct packed_struct_test {
+  PACK_STRUCT_FLD_8(u8_t  dummy1);
+  PACK_STRUCT_FIELD(u32_t dummy2);
+} PACK_STRUCT_STRUCT;
+PACK_STRUCT_END
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/epstruct.h"
+#endif
+#define PACKED_STRUCT_TEST_EXPECTED_SIZE 5
+
+#endif
+
+/* Compile-time sanity checks for configuration errors.
+ * These can be done independently of LWIP_DEBUG, without penalty.
+ */
+#ifndef BYTE_ORDER
+#error "BYTE_ORDER is not defined, you have to define it in your cc.h"
+#endif
+#if (!IP_SOF_BROADCAST && IP_SOF_BROADCAST_RECV)
+#error "If you want to use broadcast filter per pcb on recv operations, you have to define IP_SOF_BROADCAST=1 in your lwipopts.h"
+#endif
+#if (!LWIP_UDP && LWIP_UDPLITE)
+#error "If you want to use UDP Lite, you have to define LWIP_UDP=1 in your lwipopts.h"
+#endif
+#if (!LWIP_UDP && LWIP_DHCP)
+#error "If you want to use DHCP, you have to define LWIP_UDP=1 in your lwipopts.h"
+#endif
+#if (!LWIP_UDP && !LWIP_RAW && LWIP_MULTICAST_TX_OPTIONS)
+#error "If you want to use LWIP_MULTICAST_TX_OPTIONS, you have to define LWIP_UDP=1 and/or LWIP_RAW=1 in your lwipopts.h"
+#endif
+#if (!LWIP_UDP && LWIP_DNS)
+#error "If you want to use DNS, you have to define LWIP_UDP=1 in your lwipopts.h"
+#endif
+#if !MEMP_MEM_MALLOC /* MEMP_NUM_* checks are disabled when not using the pool allocator */
+#if (LWIP_ARP && ARP_QUEUEING && (MEMP_NUM_ARP_QUEUE<=0))
+#error "If you want to use ARP Queueing, you have to define MEMP_NUM_ARP_QUEUE>=1 in your lwipopts.h"
+#endif
+#if (LWIP_RAW && (MEMP_NUM_RAW_PCB<=0))
+#error "If you want to use RAW, you have to define MEMP_NUM_RAW_PCB>=1 in your lwipopts.h"
+#endif
+#if (LWIP_UDP && (MEMP_NUM_UDP_PCB<=0))
+#error "If you want to use UDP, you have to define MEMP_NUM_UDP_PCB>=1 in your lwipopts.h"
+#endif
+#if (LWIP_TCP && (MEMP_NUM_TCP_PCB<=0))
+#error "If you want to use TCP, you have to define MEMP_NUM_TCP_PCB>=1 in your lwipopts.h"
+#endif
+#if (LWIP_IGMP && (MEMP_NUM_IGMP_GROUP<=1))
+#error "If you want to use IGMP, you have to define MEMP_NUM_IGMP_GROUP>1 in your lwipopts.h"
+#endif
+#if (LWIP_IGMP && !LWIP_MULTICAST_TX_OPTIONS)
+#error "If you want to use IGMP, you have to define LWIP_MULTICAST_TX_OPTIONS==1 in your lwipopts.h"
+#endif
+#if (LWIP_IGMP && !LWIP_IPV4)
+#error "IGMP needs LWIP_IPV4 enabled in your lwipopts.h"
+#endif
+#if ((LWIP_NETCONN || LWIP_SOCKET) && (MEMP_NUM_TCPIP_MSG_API<=0))
+#error "If you want to use Sequential API, you have to define MEMP_NUM_TCPIP_MSG_API>=1 in your lwipopts.h"
+#endif
+/* There must be sufficient timeouts, taking into account requirements of the subsystems. */
+#if LWIP_TIMERS && (MEMP_NUM_SYS_TIMEOUT < LWIP_NUM_SYS_TIMEOUT_INTERNAL)
+#error "MEMP_NUM_SYS_TIMEOUT is too low to accommodate all required timeouts"
+#endif
+#if (IP_REASSEMBLY && (MEMP_NUM_REASSDATA > IP_REASS_MAX_PBUFS))
+#error "MEMP_NUM_REASSDATA > IP_REASS_MAX_PBUFS doesn't make sense since each struct ip_reassdata must hold 2 pbufs at least!"
+#endif
+#endif /* !MEMP_MEM_MALLOC */
+#if LWIP_WND_SCALE
+#if (LWIP_TCP && (TCP_WND > 0xffffffff))
+#error "If you want to use TCP, TCP_WND must fit in an u32_t, so, you have to reduce it in your lwipopts.h"
+#endif
+#if (LWIP_TCP && (TCP_RCV_SCALE > 14))
+#error "The maximum valid window scale value is 14!"
+#endif
+#if (LWIP_TCP && (TCP_WND > (0xFFFFU << TCP_RCV_SCALE)))
+#error "TCP_WND is bigger than the configured LWIP_WND_SCALE allows!"
+#endif
+#if (LWIP_TCP && ((TCP_WND >> TCP_RCV_SCALE) == 0))
+#error "TCP_WND is too small for the configured LWIP_WND_SCALE (results in zero window)!"
+#endif
+#else /* LWIP_WND_SCALE */
+#if (LWIP_TCP && (TCP_WND > 0xffff))
+#error "If you want to use TCP, TCP_WND must fit in an u16_t, so, you have to reduce it in your lwipopts.h (or enable window scaling)"
+#endif
+#endif /* LWIP_WND_SCALE */
+#if (LWIP_TCP && (TCP_SND_QUEUELEN > 0xffff))
+#error "If you want to use TCP, TCP_SND_QUEUELEN must fit in an u16_t, so, you have to reduce it in your lwipopts.h"
+#endif
+#if (LWIP_TCP && (TCP_SND_QUEUELEN < 2))
+#error "TCP_SND_QUEUELEN must be at least 2 for no-copy TCP writes to work"
+#endif
+#if (LWIP_TCP && ((TCP_MAXRTX > 12) || (TCP_SYNMAXRTX > 12)))
+#error "If you want to use TCP, TCP_MAXRTX and TCP_SYNMAXRTX must less or equal to 12 (due to tcp_backoff table), so, you have to reduce them in your lwipopts.h"
+#endif
+#if (LWIP_TCP && TCP_LISTEN_BACKLOG && ((TCP_DEFAULT_LISTEN_BACKLOG < 0) || (TCP_DEFAULT_LISTEN_BACKLOG > 0xff)))
+#error "If you want to use TCP backlog, TCP_DEFAULT_LISTEN_BACKLOG must fit into an u8_t"
+#endif
+#if (LWIP_TCP && LWIP_TCP_SACK_OUT && !TCP_QUEUE_OOSEQ)
+#error "To use LWIP_TCP_SACK_OUT, TCP_QUEUE_OOSEQ needs to be enabled"
+#endif
+#if (LWIP_TCP && LWIP_TCP_SACK_OUT && (LWIP_TCP_MAX_SACK_NUM < 1))
+#error "LWIP_TCP_MAX_SACK_NUM must be greater than 0"
+#endif
+#if (LWIP_NETIF_API && (NO_SYS==1))
+#error "If you want to use NETIF API, you have to define NO_SYS=0 in your lwipopts.h"
+#endif
+#if ((LWIP_SOCKET || LWIP_NETCONN) && (NO_SYS==1))
+#error "If you want to use Sequential API, you have to define NO_SYS=0 in your lwipopts.h"
+#endif
+#if (LWIP_PPP_API && (NO_SYS==1))
+#error "If you want to use PPP API, you have to define NO_SYS=0 in your lwipopts.h"
+#endif
+#if (LWIP_PPP_API && (PPP_SUPPORT==0))
+#error "If you want to use PPP API, you have to enable PPP_SUPPORT in your lwipopts.h"
+#endif
+#if (((!LWIP_DHCP) || (!LWIP_AUTOIP)) && LWIP_DHCP_AUTOIP_COOP)
+#error "If you want to use DHCP/AUTOIP cooperation mode, you have to define LWIP_DHCP=1 and LWIP_AUTOIP=1 in your lwipopts.h"
+#endif
+#if (((!LWIP_DHCP) || (!LWIP_ARP) || (!LWIP_ACD)) && LWIP_DHCP_DOES_ACD_CHECK)
+#error "If you want to use DHCP ACD checking, you have to define LWIP_DHCP=1, LWIP_ARP=1 and LWIP_ACD=1 in your lwipopts.h"
+#endif
+#if (!LWIP_ARP && LWIP_AUTOIP)
+#error "If you want to use AUTOIP, you have to define LWIP_ARP=1 in your lwipopts.h"
+#endif
+#if (LWIP_TCP && ((LWIP_EVENT_API && LWIP_CALLBACK_API) || (!LWIP_EVENT_API && !LWIP_CALLBACK_API)))
+#error "One and exactly one of LWIP_EVENT_API and LWIP_CALLBACK_API has to be enabled in your lwipopts.h"
+#endif
+#if (LWIP_ALTCP && LWIP_EVENT_API)
+#error "The application layered tcp API does not work with LWIP_EVENT_API"
+#endif
+#if (MEM_LIBC_MALLOC && MEM_USE_POOLS)
+#error "MEM_LIBC_MALLOC and MEM_USE_POOLS may not both be simultaneously enabled in your lwipopts.h"
+#endif
+#if (MEM_USE_POOLS && !MEMP_USE_CUSTOM_POOLS)
+#error "MEM_USE_POOLS requires custom pools (MEMP_USE_CUSTOM_POOLS) to be enabled in your lwipopts.h"
+#endif
+#if (PBUF_POOL_BUFSIZE <= MEM_ALIGNMENT)
+#error "PBUF_POOL_BUFSIZE must be greater than MEM_ALIGNMENT or the offset may take the full first pbuf"
+#endif
+#if (DNS_LOCAL_HOSTLIST && !DNS_LOCAL_HOSTLIST_IS_DYNAMIC && !(defined(DNS_LOCAL_HOSTLIST_INIT)))
+#error "you have to define define DNS_LOCAL_HOSTLIST_INIT {{'host1', 0x123}, {'host2', 0x234}} to initialize DNS_LOCAL_HOSTLIST"
+#endif
+#if PPP_SUPPORT && !PPPOS_SUPPORT && !PPPOE_SUPPORT && !PPPOL2TP_SUPPORT
+#error "PPP_SUPPORT needs at least one of PPPOS_SUPPORT, PPPOE_SUPPORT or PPPOL2TP_SUPPORT turned on"
+#endif
+#if PPP_SUPPORT && !PPP_IPV4_SUPPORT && !PPP_IPV6_SUPPORT
+#error "PPP_SUPPORT needs PPP_IPV4_SUPPORT and/or PPP_IPV6_SUPPORT turned on"
+#endif
+#if PPP_SUPPORT && PPP_IPV4_SUPPORT && !LWIP_IPV4
+#error "PPP_IPV4_SUPPORT needs LWIP_IPV4 turned on"
+#endif
+#if PPP_SUPPORT && PPP_IPV6_SUPPORT && !LWIP_IPV6
+#error "PPP_IPV6_SUPPORT needs LWIP_IPV6 turned on"
+#endif
+#if PPP_SUPPORT && CCP_SUPPORT && !MPPE_SUPPORT
+#error "CCP_SUPPORT needs MPPE_SUPPORT turned on"
+#endif
+#if !LWIP_ETHERNET && (LWIP_ARP || PPPOE_SUPPORT)
+#error "LWIP_ETHERNET needs to be turned on for LWIP_ARP or PPPOE_SUPPORT"
+#endif
+#if LWIP_TCPIP_CORE_LOCKING_INPUT && !LWIP_TCPIP_CORE_LOCKING
+#error "When using LWIP_TCPIP_CORE_LOCKING_INPUT, LWIP_TCPIP_CORE_LOCKING must be enabled, too"
+#endif
+#if LWIP_TCP && LWIP_NETIF_TX_SINGLE_PBUF && !TCP_OVERSIZE
+#error "LWIP_NETIF_TX_SINGLE_PBUF needs TCP_OVERSIZE enabled to create single-pbuf TCP packets"
+#endif
+#if LWIP_NETCONN && LWIP_TCP
+#if NETCONN_COPY != TCP_WRITE_FLAG_COPY
+#error "NETCONN_COPY != TCP_WRITE_FLAG_COPY"
+#endif
+#if NETCONN_MORE != TCP_WRITE_FLAG_MORE
+#error "NETCONN_MORE != TCP_WRITE_FLAG_MORE"
+#endif
+#endif /* LWIP_NETCONN && LWIP_TCP */
+#if LWIP_NETCONN_FULLDUPLEX && !LWIP_NETCONN_SEM_PER_THREAD
+#error "For LWIP_NETCONN_FULLDUPLEX to work, LWIP_NETCONN_SEM_PER_THREAD is required"
+#endif
+
+
+/* Compile-time checks for deprecated options.
+ */
+#ifdef MEMP_NUM_TCPIP_MSG
+#error "MEMP_NUM_TCPIP_MSG option is deprecated. Remove it from your lwipopts.h."
+#endif
+#ifdef TCP_REXMIT_DEBUG
+#error "TCP_REXMIT_DEBUG option is deprecated. Remove it from your lwipopts.h."
+#endif
+#ifdef RAW_STATS
+#error "RAW_STATS option is deprecated. Remove it from your lwipopts.h."
+#endif
+#ifdef ETHARP_QUEUE_FIRST
+#error "ETHARP_QUEUE_FIRST option is deprecated. Remove it from your lwipopts.h."
+#endif
+#ifdef ETHARP_ALWAYS_INSERT
+#error "ETHARP_ALWAYS_INSERT option is deprecated. Remove it from your lwipopts.h."
+#endif
+#if !NO_SYS && LWIP_TCPIP_CORE_LOCKING && LWIP_COMPAT_MUTEX && !defined(LWIP_COMPAT_MUTEX_ALLOWED)
+#error "LWIP_COMPAT_MUTEX cannot prevent priority inversion. It is recommended to implement priority-aware mutexes. (Define LWIP_COMPAT_MUTEX_ALLOWED to disable this error.)"
+#endif
+
+#ifndef LWIP_DISABLE_TCP_SANITY_CHECKS
+#define LWIP_DISABLE_TCP_SANITY_CHECKS  0
+#endif
+#ifndef LWIP_DISABLE_MEMP_SANITY_CHECKS
+#define LWIP_DISABLE_MEMP_SANITY_CHECKS 0
+#endif
+
+/* MEMP sanity checks */
+#if MEMP_MEM_MALLOC
+#if !LWIP_DISABLE_MEMP_SANITY_CHECKS
+#if LWIP_NETCONN || LWIP_SOCKET
+#if !MEMP_NUM_NETCONN && LWIP_SOCKET
+#error "lwip_sanity_check: WARNING: MEMP_NUM_NETCONN cannot be 0 when using sockets!"
+#endif
+#else /* MEMP_MEM_MALLOC */
+#if MEMP_NUM_NETCONN > (MEMP_NUM_TCP_PCB+MEMP_NUM_TCP_PCB_LISTEN+MEMP_NUM_UDP_PCB+MEMP_NUM_RAW_PCB)
+#error "lwip_sanity_check: WARNING: MEMP_NUM_NETCONN should be less than the sum of MEMP_NUM_{TCP,RAW,UDP}_PCB+MEMP_NUM_TCP_PCB_LISTEN. If you know what you are doing, define LWIP_DISABLE_MEMP_SANITY_CHECKS to 1 to disable this error."
+#endif
+#endif /* LWIP_NETCONN || LWIP_SOCKET */
+#endif /* !LWIP_DISABLE_MEMP_SANITY_CHECKS */
+#if MEM_USE_POOLS
+#error "MEMP_MEM_MALLOC and MEM_USE_POOLS cannot be enabled at the same time"
+#endif
+#ifdef LWIP_HOOK_MEMP_AVAILABLE
+#error "LWIP_HOOK_MEMP_AVAILABLE doesn't make sense with MEMP_MEM_MALLOC"
+#endif
+#endif /* MEMP_MEM_MALLOC */
+
+/* TCP sanity checks */
+#if !LWIP_DISABLE_TCP_SANITY_CHECKS
+#if LWIP_TCP
+#if !MEMP_MEM_MALLOC && (MEMP_NUM_TCP_SEG < TCP_SND_QUEUELEN)
+#error "lwip_sanity_check: WARNING: MEMP_NUM_TCP_SEG should be at least as big as TCP_SND_QUEUELEN. If you know what you are doing, define LWIP_DISABLE_TCP_SANITY_CHECKS to 1 to disable this error."
+#endif
+#if TCP_SND_BUF < (2 * TCP_MSS)
+#error "lwip_sanity_check: WARNING: TCP_SND_BUF must be at least as much as (2 * TCP_MSS) for things to work smoothly. If you know what you are doing, define LWIP_DISABLE_TCP_SANITY_CHECKS to 1 to disable this error."
+#endif
+#if TCP_SND_QUEUELEN < (2 * (TCP_SND_BUF / TCP_MSS))
+#error "lwip_sanity_check: WARNING: TCP_SND_QUEUELEN must be at least as much as (2 * TCP_SND_BUF/TCP_MSS) for things to work. If you know what you are doing, define LWIP_DISABLE_TCP_SANITY_CHECKS to 1 to disable this error."
+#endif
+#if TCP_SNDLOWAT >= TCP_SND_BUF
+#error "lwip_sanity_check: WARNING: TCP_SNDLOWAT must be less than TCP_SND_BUF. If you know what you are doing, define LWIP_DISABLE_TCP_SANITY_CHECKS to 1 to disable this error."
+#endif
+#if TCP_MSS >= ((16 * 1024) - 1)
+#error "lwip_sanity_check: WARNING: TCP_MSS must be <= 16382 to prevent u16_t underflow in TCP_SNDLOWAT calculation!"
+#endif
+#if TCP_SNDLOWAT >= (0xFFFF - (4 * TCP_MSS))
+#error "lwip_sanity_check: WARNING: TCP_SNDLOWAT must at least be 4*MSS below u16_t overflow!"
+#endif
+#if TCP_SNDQUEUELOWAT >= TCP_SND_QUEUELEN
+#error "lwip_sanity_check: WARNING: TCP_SNDQUEUELOWAT must be less than TCP_SND_QUEUELEN. If you know what you are doing, define LWIP_DISABLE_TCP_SANITY_CHECKS to 1 to disable this error."
+#endif
+#if !MEMP_MEM_MALLOC && PBUF_POOL_SIZE && (PBUF_POOL_BUFSIZE <= (PBUF_LINK_ENCAPSULATION_HLEN + PBUF_LINK_HLEN + PBUF_IP_HLEN + PBUF_TRANSPORT_HLEN))
+#error "lwip_sanity_check: WARNING: PBUF_POOL_BUFSIZE does not provide enough space for protocol headers. If you know what you are doing, define LWIP_DISABLE_TCP_SANITY_CHECKS to 1 to disable this error."
+#endif
+#if !MEMP_MEM_MALLOC && PBUF_POOL_SIZE && (TCP_WND > (PBUF_POOL_SIZE * (PBUF_POOL_BUFSIZE - (PBUF_LINK_ENCAPSULATION_HLEN + PBUF_LINK_HLEN + PBUF_IP_HLEN + PBUF_TRANSPORT_HLEN))))
+#error "lwip_sanity_check: WARNING: TCP_WND is larger than space provided by PBUF_POOL_SIZE * (PBUF_POOL_BUFSIZE - protocol headers). If you know what you are doing, define LWIP_DISABLE_TCP_SANITY_CHECKS to 1 to disable this error."
+#endif
+#if TCP_WND < TCP_MSS
+#error "lwip_sanity_check: WARNING: TCP_WND is smaller than MSS. If you know what you are doing, define LWIP_DISABLE_TCP_SANITY_CHECKS to 1 to disable this error."
+#endif
+#endif /* LWIP_TCP */
+#endif /* !LWIP_DISABLE_TCP_SANITY_CHECKS */
+
+/**
+ * @ingroup lwip_nosys
+ * Initialize all modules.
+ * Use this in NO_SYS mode. Use tcpip_init() otherwise.
+ */
+void
+lwip_init(void)
+{
+#ifndef LWIP_SKIP_CONST_CHECK
+  int a = 0;
+  LWIP_UNUSED_ARG(a);
+  LWIP_ASSERT("LWIP_CONST_CAST not implemented correctly. Check your lwIP port.", LWIP_CONST_CAST(void *, &a) == &a);
+#endif
+#ifndef LWIP_SKIP_PACKING_CHECK
+  LWIP_ASSERT("Struct packing not implemented correctly. Check your lwIP port.", sizeof(struct packed_struct_test) == PACKED_STRUCT_TEST_EXPECTED_SIZE);
+#endif
+
+  /* Modules initialization */
+  stats_init();
+#if !NO_SYS
+  sys_init();
+#endif /* !NO_SYS */
+  mem_init();
+  memp_init();
+  pbuf_init();
+  netif_init();
+#if LWIP_IPV4
+  ip_init();
+#if LWIP_ARP
+  etharp_init();
+#endif /* LWIP_ARP */
+#endif /* LWIP_IPV4 */
+#if LWIP_RAW
+  raw_init();
+#endif /* LWIP_RAW */
+#if LWIP_UDP
+  udp_init();
+#endif /* LWIP_UDP */
+#if LWIP_TCP
+  tcp_init();
+#endif /* LWIP_TCP */
+#if LWIP_IGMP
+  igmp_init();
+#endif /* LWIP_IGMP */
+#if LWIP_DNS
+  dns_init();
+#endif /* LWIP_DNS */
+#if PPP_SUPPORT
+  ppp_init();
+#endif
+
+#if LWIP_TIMERS
+  sys_timeouts_init();
+#endif /* LWIP_TIMERS */
+}

Drivers/LwIP/src/core/ip.c

@@ -0,0 +1,167 @@
+/**
+ * @file
+ * Common IPv4 and IPv6 code
+ *
+ * @defgroup ip IP
+ * @ingroup callbackstyle_api
+ *
+ * @defgroup ip4 IPv4
+ * @ingroup ip
+ *
+ * @defgroup ip6 IPv6
+ * @ingroup ip
+ *
+ * @defgroup ipaddr IP address handling
+ * @ingroup infrastructure
+ *
+ * @defgroup ip4addr IPv4 only
+ * @ingroup ipaddr
+ *
+ * @defgroup ip6addr IPv6 only
+ * @ingroup ipaddr
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+
+#include "lwip/opt.h"
+
+#if LWIP_IPV4 || LWIP_IPV6
+
+#include "lwip/ip_addr.h"
+#include "lwip/ip.h"
+
+/** Global data for both IPv4 and IPv6 */
+struct ip_globals ip_data;
+
+#if LWIP_IPV4 && LWIP_IPV6
+
+const ip_addr_t ip_addr_any_type = IPADDR_ANY_TYPE_INIT;
+
+/**
+ * @ingroup ipaddr
+ * Convert numeric IP address (both versions) into ASCII representation.
+ * returns ptr to static buffer; not reentrant!
+ *
+ * @param addr ip address in network order to convert
+ * @return pointer to a global static (!) buffer that holds the ASCII
+ *         representation of addr
+ */
+char *ipaddr_ntoa(const ip_addr_t *addr)
+{
+  if (addr == NULL) {
+    return NULL;
+  }
+  if (IP_IS_V6(addr)) {
+    return ip6addr_ntoa(ip_2_ip6(addr));
+  } else {
+    return ip4addr_ntoa(ip_2_ip4(addr));
+  }
+}
+
+/**
+ * @ingroup ipaddr
+ * Same as ipaddr_ntoa, but reentrant since a user-supplied buffer is used.
+ *
+ * @param addr ip address in network order to convert
+ * @param buf target buffer where the string is stored
+ * @param buflen length of buf
+ * @return either pointer to buf which now holds the ASCII
+ *         representation of addr or NULL if buf was too small
+ */
+char *ipaddr_ntoa_r(const ip_addr_t *addr, char *buf, int buflen)
+{
+  if (addr == NULL) {
+    return NULL;
+  }
+  if (IP_IS_V6(addr)) {
+    return ip6addr_ntoa_r(ip_2_ip6(addr), buf, buflen);
+  } else {
+    return ip4addr_ntoa_r(ip_2_ip4(addr), buf, buflen);
+  }
+}
+
+/**
+ * @ingroup ipaddr
+ * Convert IP address string (both versions) to numeric.
+ * The version is auto-detected from the string.
+ *
+ * @param cp IP address string to convert
+ * @param addr conversion result is stored here
+ * @return 1 on success, 0 on error
+ */
+int
+ipaddr_aton(const char *cp, ip_addr_t *addr)
+{
+  if (cp != NULL) {
+    const char *c;
+    for (c = cp; *c != 0; c++) {
+      if (*c == ':') {
+        /* contains a colon: IPv6 address */
+        if (addr) {
+          IP_SET_TYPE_VAL(*addr, IPADDR_TYPE_V6);
+        }
+        return ip6addr_aton(cp, ip_2_ip6(addr));
+      } else if (*c == '.') {
+        /* contains a dot: IPv4 address */
+        break;
+      }
+    }
+    /* call ip4addr_aton as fallback or if IPv4 was found */
+    if (addr) {
+      IP_SET_TYPE_VAL(*addr, IPADDR_TYPE_V4);
+    }
+    return ip4addr_aton(cp, ip_2_ip4(addr));
+  }
+  return 0;
+}
+
+/**
+ * @ingroup lwip_nosys
+ * If both IP versions are enabled, this function can dispatch packets to the correct one.
+ * Don't call directly, pass to netif_add() and call netif->input().
+ */
+err_t
+ip_input(struct pbuf *p, struct netif *inp)
+{
+  if (p != NULL) {
+    if (IP_HDR_GET_VERSION(p->payload) == 6) {
+      return ip6_input(p, inp);
+    }
+    return ip4_input(p, inp);
+  }
+  return ERR_VAL;
+}
+
+#endif /* LWIP_IPV4 && LWIP_IPV6 */
+
+#endif /* LWIP_IPV4 || LWIP_IPV6 */

Drivers/LwIP/src/core/ipv4/acd.c

@@ -0,0 +1,557 @@
+/**
+ * @file
+ *
+ * ACD IPv4 Address Conflict Detection
+ *
+ * This is an IPv4 address conflict detection implementation for the lwIP TCP/IP
+ * stack. It aims to be conform to RFC5227.
+ *
+ * @defgroup acd ACD
+ * @ingroup ip4
+ * ACD related functions
+ * USAGE:
+ *
+ * define @ref LWIP_ACD 1 in your lwipopts.h
+ * Options:
+ * ACD_TMR_INTERVAL msecs,
+ *   I recommend a value of 100. The value must divide 1000 with a remainder almost 0.
+ *   Possible values are 1000, 500, 333, 250, 200, 166, 142, 125, 111, 100 ....
+ *
+ * For fixed IP:
+ * - call acd_start after selecting an IP address. The caller will be informed
+ *   on conflict status via the callback function.
+ *
+ * With AUTOIP:
+ * - will be called from the autoip module. No extra's needed.
+ *
+ * With DHCP:
+ * - enable LWIP_DHCP_DOES_ACD_CHECK. Then it will be called from the dhcp module.
+ *   No extra's needed.
+ */
+
+/*
+ *
+ * Copyright (c) 2007 Dominik Spies <kontakt@dspies.de>
+ * Copyright (c) 2018 Jasper Verschueren <jasper.verschueren@apart-audio.com>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * Author: Jasper Verschueren <jasper.verschueren@apart-audio.com>
+ * Author: Dominik Spies <kontakt@dspies.de>
+ */
+
+#include "lwip/opt.h"
+
+/* don't build if not configured for use in lwipopts.h */
+#if LWIP_IPV4 && LWIP_ACD
+
+#include <string.h>
+
+#include "lwip/acd.h"
+#include "lwip/prot/acd.h"
+
+#define ACD_FOREACH(acd, acd_list) for ((acd) = acd_list; (acd) != NULL; (acd) = (acd)->next)
+
+#define ACD_TICKS_PER_SECOND  (1000 / ACD_TMR_INTERVAL)
+
+/* Define good random function (LWIP_RAND) in lwipopts.h */
+#ifdef LWIP_RAND
+#define LWIP_ACD_RAND(netif, acd)    LWIP_RAND()
+#else /* LWIP_RAND */
+#ifdef LWIP_AUTOIP_RAND
+#include "lwip/autoip.h"
+#define LWIP_ACD_RAND(netif, acd)    LWIP_AUTOIP_RAND(netif) /* for backwards compatibility */
+#else
+#define LWIP_ACD_RAND(netif, acd) ((((u32_t)((netif->hwaddr[5]) & 0xff) << 24) | \
+                                    ((u32_t)((netif->hwaddr[3]) & 0xff) << 16) | \
+                                    ((u32_t)((netif->hwaddr[2]) & 0xff) << 8) | \
+                                    ((u32_t)((netif->hwaddr[4]) & 0xff))) + \
+                                    (acd->sent_num))
+#endif /* LWIP_AUTOIP_RAND */
+#endif /* LWIP_RAND */
+
+
+#define ACD_RANDOM_PROBE_WAIT(netif, acd) (LWIP_ACD_RAND(netif, acd) % \
+                                    (PROBE_WAIT * ACD_TICKS_PER_SECOND))
+
+#define ACD_RANDOM_PROBE_INTERVAL(netif, acd) ((LWIP_ACD_RAND(netif, acd) % \
+                                    ((PROBE_MAX - PROBE_MIN) * ACD_TICKS_PER_SECOND)) + \
+                                    (PROBE_MIN * ACD_TICKS_PER_SECOND ))
+
+/* Function definitions */
+static void acd_restart(struct netif *netif, struct acd *acd);
+static void acd_handle_arp_conflict(struct netif *netif, struct acd *acd);
+static void acd_put_in_passive_mode(struct netif *netif, struct acd *acd);
+
+/**
+ * @ingroup acd
+ * Add ACD client to the client list and initialize callback function
+ *
+ * @param netif                 network interface on which to start the acd
+ *                              client
+ * @param acd                   acd module to be added to the list
+ * @param acd_conflict_callback callback to be called when conflict information
+ *                              is available
+ */
+err_t
+acd_add(struct netif *netif, struct acd *acd,
+         acd_conflict_callback_t acd_conflict_callback)
+{
+  struct acd *acd2;
+
+  /* Set callback */
+  LWIP_ASSERT_CORE_LOCKED();
+  LWIP_ASSERT("acd_conflict_callback != NULL", acd_conflict_callback != NULL);
+  acd->acd_conflict_callback = acd_conflict_callback;
+
+  /* Check if the acd struct is already added */
+  for (acd2 = netif->acd_list; acd2 != NULL; acd2 = acd2->next) {
+    if (acd2 == acd) {
+      LWIP_DEBUGF(ACD_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
+                  ("acd_add(): acd already added to list\n"));
+      return ERR_OK;
+    }
+  }
+
+  /* add acd struct to the list */
+  acd->next = netif->acd_list;
+  netif->acd_list = acd;
+
+  return ERR_OK;
+}
+
+/**
+ * @ingroup acd
+ * Remvoe ACD client from the client list
+ *
+ * @param netif network interface from which to remove the acd client
+ * @param acd   acd module to be removed from the list
+ */
+void
+acd_remove(struct netif *netif, struct acd *acd)
+{
+  struct acd *acd2, *prev = NULL;
+
+  LWIP_ASSERT_CORE_LOCKED();
+
+  for (acd2 = netif->acd_list; acd2 != NULL; acd2 = acd2->next) {
+    if (acd2 == acd) {
+      if (prev) {
+        prev->next = acd->next;
+      } else {
+        netif->acd_list = acd->next;
+      }
+      return;
+    }
+    prev = acd2;
+  }
+  LWIP_ASSERT(("acd_remove(): acd not on list\n"), 0);
+}
+
+
+/**
+ * @ingroup acd
+ * Start ACD client
+ *
+ * @param netif   network interface on which to start the acd client
+ * @param acd     acd module to start
+ * @param ipaddr  ip address to perform acd on
+ */
+err_t
+acd_start(struct netif *netif, struct acd *acd, ip4_addr_t ipaddr)
+{
+  err_t result = ERR_OK;
+
+  LWIP_UNUSED_ARG(netif);
+  LWIP_DEBUGF(ACD_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
+              ("acd_start(netif=%p) %c%c%"U16_F"\n",
+              (void *)netif, netif->name[0],
+               netif->name[1], (u16_t)netif->num));
+
+  /* init probing state */
+  acd->sent_num = 0;
+  acd->lastconflict = 0;
+  ip4_addr_copy(acd->ipaddr, ipaddr);
+  acd->state = ACD_STATE_PROBE_WAIT;
+
+  acd->ttw = (u16_t)(ACD_RANDOM_PROBE_WAIT(netif, acd));
+
+  return result;
+}
+
+/**
+ * @ingroup acd
+ * Stop ACD client
+ *
+ * @param acd   acd module to stop
+ */
+err_t
+acd_stop(struct acd *acd)
+{
+  LWIP_DEBUGF(ACD_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("acd_stop\n"));
+
+  if (acd != NULL) {
+    acd->state = ACD_STATE_OFF;
+  }
+  return ERR_OK;
+}
+
+/**
+ * @ingroup acd
+ * Inform the ACD modules when the link goes down
+ *
+ * @param netif network interface on which to inform the ACD clients
+ */
+void
+acd_network_changed_link_down(struct netif *netif)
+{
+  struct acd *acd;
+  /* loop over the acd's*/
+  ACD_FOREACH(acd, netif->acd_list) {
+    acd_stop(acd);
+  }
+}
+
+/**
+ * Has to be called in loop every ACD_TMR_INTERVAL milliseconds
+ */
+void
+acd_tmr(void)
+{
+  struct netif *netif;
+  struct acd *acd;
+  /* loop through netif's */
+  NETIF_FOREACH(netif) {
+    ACD_FOREACH(acd, netif->acd_list) {
+      if (acd->lastconflict > 0) {
+        acd->lastconflict--;
+      }
+
+      LWIP_DEBUGF(ACD_DEBUG | LWIP_DBG_TRACE,
+                  ("acd_tmr() ACD-State: %"U16_F", ttw=%"U16_F"\n",
+                   (u16_t)(acd->state), acd->ttw));
+
+      if (acd->ttw > 0) {
+        acd->ttw--;
+      }
+
+      switch (acd->state) {
+        case ACD_STATE_PROBE_WAIT:
+        case ACD_STATE_PROBING:
+          if (acd->ttw == 0) {
+            acd->state = ACD_STATE_PROBING;
+            etharp_acd_probe(netif, &acd->ipaddr);
+            LWIP_DEBUGF(ACD_DEBUG | LWIP_DBG_TRACE,
+                        ("acd_tmr() PROBING Sent Probe\n"));
+            acd->sent_num++;
+            if (acd->sent_num >= PROBE_NUM) {
+              /* Switch to ANNOUNCE_WAIT: last probe is sent*/
+              acd->state = ACD_STATE_ANNOUNCE_WAIT;
+
+              acd->sent_num = 0;
+
+              /* calculate time to wait before announcing */
+              acd->ttw = (u16_t)(ANNOUNCE_WAIT * ACD_TICKS_PER_SECOND);
+            } else {
+              /* calculate time to wait to next probe */
+              acd->ttw = (u16_t)(ACD_RANDOM_PROBE_INTERVAL(netif, acd));
+            }
+          }
+          break;
+
+        case ACD_STATE_ANNOUNCE_WAIT:
+        case ACD_STATE_ANNOUNCING:
+          if (acd->ttw == 0) {
+            if (acd->sent_num == 0) {
+              acd->state = ACD_STATE_ANNOUNCING;
+
+              /* reset conflict count to ensure fast re-probing after announcing */
+              acd->num_conflicts = 0;
+
+              LWIP_DEBUGF(ACD_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
+                    ("acd_tmr(): changing state to ANNOUNCING: %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
+                     ip4_addr1_16(&acd->ipaddr), ip4_addr2_16(&acd->ipaddr),
+                     ip4_addr3_16(&acd->ipaddr), ip4_addr4_16(&acd->ipaddr)));
+            }
+
+            etharp_acd_announce(netif, &acd->ipaddr);
+            LWIP_DEBUGF(ACD_DEBUG | LWIP_DBG_TRACE,
+                        ("acd_tmr() ANNOUNCING Sent Announce\n"));
+            acd->ttw = ANNOUNCE_INTERVAL * ACD_TICKS_PER_SECOND;
+            acd->sent_num++;
+
+            if (acd->sent_num >= ANNOUNCE_NUM) {
+              acd->state = ACD_STATE_ONGOING;
+              acd->sent_num = 0;
+              acd->ttw = 0;
+              LWIP_DEBUGF(ACD_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
+                    ("acd_tmr(): changing state to ONGOING: %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
+                     ip4_addr1_16(&acd->ipaddr), ip4_addr2_16(&acd->ipaddr),
+                     ip4_addr3_16(&acd->ipaddr), ip4_addr4_16(&acd->ipaddr)));
+
+              /* finally, let acd user know that the address is good and can be used */
+              acd->acd_conflict_callback(netif, ACD_IP_OK);
+            }
+          }
+          break;
+
+        case ACD_STATE_RATE_LIMIT:
+          if (acd->ttw == 0) {
+            /* acd should be stopped because ipaddr isn't valid any more */
+            acd_stop(acd);
+            /* let the acd user (after rate limit interval) know that their is
+             * a conflict detected. So it can restart the address acquiring
+             * process.*/
+            acd->acd_conflict_callback(netif, ACD_RESTART_CLIENT);
+          }
+          break;
+
+        default:
+          /* nothing to do in other states */
+          break;
+      }
+    }
+  }
+}
+
+/**
+ * Restarts the acd module
+ *
+ * The number of conflicts is increased and the upper layer is informed.
+ */
+static void
+acd_restart(struct netif *netif, struct acd *acd)
+{
+  /* increase conflict counter. */
+  acd->num_conflicts++;
+
+  /* Decline the address */
+  acd->acd_conflict_callback(netif, ACD_DECLINE);
+
+  /* if we tried more then MAX_CONFLICTS we must limit our rate for
+   * acquiring and probing addresses. compliant to RFC 5227 Section 2.1.1 */
+  if (acd->num_conflicts >= MAX_CONFLICTS) {
+    acd->state = ACD_STATE_RATE_LIMIT;
+    acd->ttw = (u16_t)(RATE_LIMIT_INTERVAL * ACD_TICKS_PER_SECOND);
+    LWIP_DEBUGF(ACD_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | LWIP_DBG_LEVEL_WARNING,
+                ("acd_restart(): rate limiting initiated. too many conflicts\n"));
+  }
+  else {
+    /* acd should be stopped because ipaddr isn't valid any more */
+    acd_stop(acd);
+    /* let the acd user know right away that their is a conflict detected.
+     * So it can restart the address acquiring process. */
+    acd->acd_conflict_callback(netif, ACD_RESTART_CLIENT);
+  }
+}
+
+/**
+ * Handles every incoming ARP Packet, called by etharp_input().
+ *
+ * @param netif network interface to use for acd processing
+ * @param hdr   Incoming ARP packet
+ */
+void
+acd_arp_reply(struct netif *netif, struct etharp_hdr *hdr)
+{
+  struct acd *acd;
+  ip4_addr_t sipaddr, dipaddr;
+  struct eth_addr netifaddr;
+  SMEMCPY(netifaddr.addr, netif->hwaddr, ETH_HWADDR_LEN);
+
+  /* Copy struct ip4_addr_wordaligned to aligned ip4_addr, to support
+   * compilers without structure packing (not using structure copy which
+   * breaks strict-aliasing rules).
+   */
+  IPADDR_WORDALIGNED_COPY_TO_IP4_ADDR_T(&sipaddr, &hdr->sipaddr);
+  IPADDR_WORDALIGNED_COPY_TO_IP4_ADDR_T(&dipaddr, &hdr->dipaddr);
+
+  LWIP_DEBUGF(ACD_DEBUG | LWIP_DBG_TRACE, ("acd_arp_reply()\n"));
+
+  /* loop over the acd's*/
+  ACD_FOREACH(acd, netif->acd_list) {
+    switch(acd->state) {
+      case ACD_STATE_OFF:
+      case ACD_STATE_RATE_LIMIT:
+      default:
+        /* do nothing */
+        break;
+
+      case ACD_STATE_PROBE_WAIT:
+      case ACD_STATE_PROBING:
+      case ACD_STATE_ANNOUNCE_WAIT:
+        /* RFC 5227 Section 2.1.1:
+         * from beginning to after ANNOUNCE_WAIT seconds we have a conflict if
+         * ip.src == ipaddr (someone is already using the address)
+         * OR
+         * ip.dst == ipaddr && hw.src != own hwaddr (someone else is probing it)
+         */
+        if ((ip4_addr_eq(&sipaddr, &acd->ipaddr)) ||
+            (ip4_addr_isany_val(sipaddr) &&
+             ip4_addr_eq(&dipaddr, &acd->ipaddr) &&
+             !eth_addr_eq(&netifaddr, &hdr->shwaddr))) {
+          LWIP_DEBUGF(ACD_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | LWIP_DBG_LEVEL_WARNING,
+                      ("acd_arp_reply(): Probe Conflict detected\n"));
+          acd_restart(netif, acd);
+        }
+        break;
+
+      case ACD_STATE_ANNOUNCING:
+      case ACD_STATE_ONGOING:
+      case ACD_STATE_PASSIVE_ONGOING:
+        /* RFC 5227 Section 2.4:
+         * in any state we have a conflict if
+         * ip.src == ipaddr && hw.src != own hwaddr (someone is using our address)
+         */
+        if (ip4_addr_eq(&sipaddr, &acd->ipaddr) &&
+            !eth_addr_eq(&netifaddr, &hdr->shwaddr)) {
+          LWIP_DEBUGF(ACD_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | LWIP_DBG_LEVEL_WARNING,
+                      ("acd_arp_reply(): Conflicting ARP-Packet detected\n"));
+          acd_handle_arp_conflict(netif, acd);
+        }
+        break;
+    }
+  }
+}
+
+/**
+ * Handle a IP address conflict after an ARP conflict detection
+ */
+static void
+acd_handle_arp_conflict(struct netif *netif, struct acd *acd)
+{
+  /* RFC5227, 2.4 "Ongoing Address Conflict Detection and Address Defense"
+     allows three options where:
+     a) means retreat on the first conflict,
+     b) allows to keep an already configured address when having only one
+        conflict in DEFEND_INTERVAL seconds and
+     c) the host will not give up it's address and defend it indefinitely
+
+     We use option b) when the acd module represents the netif address, since it
+     helps to improve the chance that one of the two conflicting hosts may be
+     able to retain its address. while we are flexible enough to help network
+     performance
+
+     We use option a) when the acd module does not represent the netif address,
+     since we cannot have the acd module announcing or restarting. This
+     situation occurs for the LL acd module when a routable address is used on
+     the netif but the LL address is still open in the background. */
+
+  if (acd->state == ACD_STATE_PASSIVE_ONGOING) {
+    /* Immediately back off on a conflict. */
+    LWIP_DEBUGF(ACD_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
+      ("acd_handle_arp_conflict(): conflict when we are in passive mode -> back off\n"));
+    acd_stop(acd);
+    acd->acd_conflict_callback(netif, ACD_DECLINE);
+  }
+  else {
+    if (acd->lastconflict > 0) {
+      /* retreat, there was a conflicting ARP in the last DEFEND_INTERVAL seconds */
+      LWIP_DEBUGF(ACD_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
+        ("acd_handle_arp_conflict(): conflict within DEFEND_INTERVAL -> retreating\n"));
+
+      /* Active TCP sessions are aborted when removing the ip address but a bad
+       * connection was inevitable anyway with conflicting hosts */
+       acd_restart(netif, acd);
+    } else {
+      LWIP_DEBUGF(ACD_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
+          ("acd_handle_arp_conflict(): we are defending, send ARP Announce\n"));
+      etharp_acd_announce(netif, &acd->ipaddr);
+      acd->lastconflict = DEFEND_INTERVAL * ACD_TICKS_PER_SECOND;
+    }
+  }
+}
+
+/**
+ * Put the acd module in passive ongoing conflict detection.
+ */
+static void
+acd_put_in_passive_mode(struct netif *netif, struct acd *acd)
+{
+  switch(acd->state) {
+    case ACD_STATE_OFF:
+    case ACD_STATE_PASSIVE_ONGOING:
+    default:
+      /* do nothing */
+      break;
+
+    case ACD_STATE_PROBE_WAIT:
+    case ACD_STATE_PROBING:
+    case ACD_STATE_ANNOUNCE_WAIT:
+    case ACD_STATE_RATE_LIMIT:
+      acd_stop(acd);
+      acd->acd_conflict_callback(netif, ACD_DECLINE);
+      break;
+
+    case ACD_STATE_ANNOUNCING:
+    case ACD_STATE_ONGOING:
+      acd->state = ACD_STATE_PASSIVE_ONGOING;
+      LWIP_DEBUGF(ACD_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
+        ("acd_put_in_passive_mode()\n"));
+      break;
+  }
+}
+
+/**
+ * @ingroup acd
+ * Inform the ACD modules of address changes
+ *
+ * @param netif     network interface on which the address is changing
+ * @param old_addr  old ip address
+ * @param new_addr  new ip address
+ */
+void
+acd_netif_ip_addr_changed(struct netif *netif, const ip_addr_t *old_addr,
+                          const ip_addr_t *new_addr)
+{
+  struct acd *acd;
+
+  LWIP_DEBUGF(ACD_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
+    ("acd_netif_ip_addr_changed(): Address changed\n"));
+
+  LWIP_DEBUGF(ACD_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
+    ("acd_netif_ip_addr_changed(): old address = %s\n", ipaddr_ntoa(old_addr)));
+  LWIP_DEBUGF(ACD_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
+    ("acd_netif_ip_addr_changed(): new address = %s\n", ipaddr_ntoa(new_addr)));
+
+  /* If we change from ANY to an IP or from an IP to ANY we do nothing */
+  if (ip_addr_isany(old_addr) || ip_addr_isany(new_addr)) {
+    return;
+  }
+
+  ACD_FOREACH(acd, netif->acd_list) {
+    /* Find ACD module of old address */
+    if(ip4_addr_eq(&acd->ipaddr, ip_2_ip4(old_addr))) {
+      /* Did we change from a LL address to a routable address? */
+      if (ip_addr_islinklocal(old_addr) && !ip_addr_islinklocal(new_addr)) {
+        LWIP_DEBUGF(ACD_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
+          ("acd_netif_ip_addr_changed(): changed from LL to routable address\n"));
+        /* Put the module in passive conflict detection mode */
+        acd_put_in_passive_mode(netif, acd);
+      }
+    }
+  }
+}
+
+#endif /* LWIP_IPV4 && LWIP_ACD */

Drivers/LwIP/src/core/ipv4/autoip.c

@@ -0,0 +1,379 @@
+/**
+ * @file
+ * AutoIP Automatic LinkLocal IP Configuration
+ *
+ * This is a AutoIP implementation for the lwIP TCP/IP stack. It aims to conform
+ * with RFC 3927. It uses IPv4 address conflict detection to evaluate the chosen
+ * address. The ACD module aims to be conform to RFC 5227.
+ * RFC 5227 is extracted out of RFC 3927 so the acd module fits nicely in autoip.
+ *
+ * @defgroup autoip AUTOIP
+ * @ingroup ip4
+ * AUTOIP related functions
+ * USAGE:
+ *
+ * define @ref LWIP_AUTOIP 1 in your lwipopts.h
+ *
+ * Without DHCP:
+ * - Call autoip_start() after netif_add().
+ *
+ * With DHCP:
+ * - define @ref LWIP_DHCP_AUTOIP_COOP 1 in your lwipopts.h.
+ * - Configure your DHCP Client.
+ *
+ * @see netifapi_autoip
+ */
+
+/*
+ *
+ * Copyright (c) 2007 Dominik Spies <kontakt@dspies.de>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * Author: Dominik Spies <kontakt@dspies.de>
+ */
+
+#include "lwip/opt.h"
+
+#if LWIP_IPV4 && LWIP_AUTOIP /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/mem.h"
+/* #include "lwip/udp.h" */
+#include "lwip/ip_addr.h"
+#include "lwip/netif.h"
+#include "lwip/autoip.h"
+#include "lwip/acd.h"
+#include "lwip/etharp.h"
+#include "lwip/prot/autoip.h"
+
+#include <string.h>
+
+/**
+ * Macro that generates the initial IP address to be tried by AUTOIP.
+ * If you want to override this, define it to something else in lwipopts.h.
+ */
+#ifndef LWIP_AUTOIP_CREATE_SEED_ADDR
+#define LWIP_AUTOIP_CREATE_SEED_ADDR(netif) \
+  lwip_htonl(AUTOIP_RANGE_START + ((u32_t)(((u8_t)(netif->hwaddr[4])) | \
+                 ((u32_t)((u8_t)(netif->hwaddr[5]))) << 8)))
+#endif /* LWIP_AUTOIP_CREATE_SEED_ADDR */
+
+/* Function definitions */
+static void autoip_restart(struct netif *netif);
+static void autoip_create_addr(struct netif *netif, ip4_addr_t *ipaddr);
+static err_t autoip_bind(struct netif *netif);
+static void autoip_conflict_callback(struct netif *netif,
+                                     acd_callback_enum_t state);
+
+/**
+ * @ingroup autoip
+ * Set a statically allocated struct autoip to work with.
+ * Using this prevents autoip_start to allocate it using mem_malloc.
+ *
+ * @param netif the netif for which to set the struct autoip
+ * @param autoip (uninitialised) autoip struct allocated by the application
+ */
+void
+autoip_set_struct(struct netif *netif, struct autoip *autoip)
+{
+  LWIP_ASSERT_CORE_LOCKED();
+  LWIP_ASSERT("netif != NULL", netif != NULL);
+  LWIP_ASSERT("autoip != NULL", autoip != NULL);
+  LWIP_ASSERT("netif already has a struct autoip set",
+              netif_autoip_data(netif) == NULL);
+
+  /* clear data structure */
+  memset(autoip, 0, sizeof(struct autoip));
+  /* autoip->state = AUTOIP_STATE_OFF; */
+  netif_set_client_data(netif, LWIP_NETIF_CLIENT_DATA_INDEX_AUTOIP, autoip);
+}
+
+/**
+ * @ingroup autoip
+ * Remove a struct autoip previously set to the netif using autoip_set_struct()
+ *
+ * @param netif the netif for which to set the struct autoip
+ */
+void
+autoip_remove_struct(struct netif *netif)
+{
+  LWIP_ASSERT_CORE_LOCKED();
+  LWIP_ASSERT("netif != NULL", netif != NULL);
+  LWIP_ASSERT("netif has no struct autoip set",
+              netif_autoip_data(netif) != NULL);
+
+  netif_set_client_data(netif, LWIP_NETIF_CLIENT_DATA_INDEX_AUTOIP, NULL);
+}
+
+/** Restart AutoIP client and check the next address (conflict detected)
+ *
+ * @param netif The netif under AutoIP control
+ */
+static void
+autoip_restart(struct netif *netif)
+{
+  struct autoip *autoip = netif_autoip_data(netif);
+  autoip->tried_llipaddr++;
+  autoip_start(netif);
+}
+
+
+/**
+ * Create an IP-Address out of range 169.254.1.0 to 169.254.254.255
+ *
+ * @param netif network interface on which create the IP-Address
+ * @param ipaddr ip address to initialize
+ */
+static void
+autoip_create_addr(struct netif *netif, ip4_addr_t *ipaddr)
+{
+  struct autoip *autoip = netif_autoip_data(netif);
+
+  /* Here we create an IP-Address out of range 169.254.1.0 to 169.254.254.255
+   * compliant to RFC 3927 Section 2.1
+   * We have 254 * 256 possibilities */
+
+  u32_t addr = lwip_ntohl(LWIP_AUTOIP_CREATE_SEED_ADDR(netif));
+  addr += autoip->tried_llipaddr;
+  addr = AUTOIP_NET | (addr & 0xffff);
+  /* Now, 169.254.0.0 <= addr <= 169.254.255.255 */
+
+  if (addr < AUTOIP_RANGE_START) {
+    addr += AUTOIP_RANGE_END - AUTOIP_RANGE_START + 1;
+  }
+  if (addr > AUTOIP_RANGE_END) {
+    addr -= AUTOIP_RANGE_END - AUTOIP_RANGE_START + 1;
+  }
+  LWIP_ASSERT("AUTOIP address not in range", (addr >= AUTOIP_RANGE_START) &&
+              (addr <= AUTOIP_RANGE_END));
+  ip4_addr_set_u32(ipaddr, lwip_htonl(addr));
+
+  LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
+              ("autoip_create_addr(): tried_llipaddr=%"U16_F", %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
+               (u16_t)(autoip->tried_llipaddr), ip4_addr1_16(ipaddr), ip4_addr2_16(ipaddr),
+               ip4_addr3_16(ipaddr), ip4_addr4_16(ipaddr)));
+}
+
+
+/**
+ * Configure interface for use with current LL IP-Address
+ *
+ * @param netif network interface to configure with current LL IP-Address
+ */
+static err_t
+autoip_bind(struct netif *netif)
+{
+  struct autoip *autoip = netif_autoip_data(netif);
+  ip4_addr_t sn_mask, gw_addr;
+
+  autoip->state = AUTOIP_STATE_BOUND;
+
+  LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
+              ("autoip_bind(netif=%p) %c%c%"U16_F" %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
+               (void *)netif, netif->name[0], netif->name[1], (u16_t)netif->num,
+               ip4_addr1_16(&autoip->llipaddr), ip4_addr2_16(&autoip->llipaddr),
+               ip4_addr3_16(&autoip->llipaddr), ip4_addr4_16(&autoip->llipaddr)));
+
+  IP4_ADDR(&sn_mask, 255, 255, 0, 0);
+  IP4_ADDR(&gw_addr, 0, 0, 0, 0);
+
+  netif_set_addr(netif, &autoip->llipaddr, &sn_mask, &gw_addr);
+  /* interface is used by routing now that an address is set */
+
+  return ERR_OK;
+}
+
+/**
+* Handle conflict information from ACD module
+*
+* @param netif   network interface to handle conflict information on
+* @param state   acd_callback_enum_t
+ */
+static void
+autoip_conflict_callback(struct netif *netif, acd_callback_enum_t state)
+{
+  struct autoip *autoip = netif_autoip_data(netif);
+
+  switch (state) {
+    case ACD_IP_OK:
+      autoip_bind(netif);
+      break;
+    case ACD_RESTART_CLIENT:
+      autoip_restart(netif);
+      break;
+    case ACD_DECLINE:
+      /* "delete" conflicting address so a new one will be selected in
+       * autoip_start() */
+      ip4_addr_set_any(&autoip->llipaddr);
+      autoip_stop(netif);
+      break;
+      default:
+      break;
+  }
+}
+
+/**
+ * @ingroup autoip
+ * Start AutoIP client
+ *
+ * @param netif network interface on which start the AutoIP client
+ */
+err_t
+autoip_start(struct netif *netif)
+{
+  struct autoip *autoip = netif_autoip_data(netif);
+  err_t result = ERR_OK;
+
+  LWIP_ASSERT_CORE_LOCKED();
+  LWIP_ERROR("netif is not up, old style port?", netif_is_up(netif), return ERR_ARG;);
+
+  if (autoip == NULL) {
+    /* no AutoIP client attached yet? */
+    LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
+                ("autoip_start(): starting new AUTOIP client\n"));
+    autoip = (struct autoip *)mem_calloc(1, sizeof(struct autoip));
+    if (autoip == NULL) {
+      LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
+                  ("autoip_start(): could not allocate autoip\n"));
+      return ERR_MEM;
+    }
+    /* store this AutoIP client in the netif */
+    netif_set_client_data(netif, LWIP_NETIF_CLIENT_DATA_INDEX_AUTOIP, autoip);
+    LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, ("autoip_start(): allocated autoip\n"));
+  }
+
+  if (autoip->state == AUTOIP_STATE_OFF) {
+    LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
+                ("autoip_start(netif=%p) %c%c%"U16_F"\n", (void *)netif, netif->name[0],
+                 netif->name[1], (u16_t)netif->num));
+
+    /* add acd struct to list*/
+    acd_add(netif, &autoip->acd, autoip_conflict_callback);
+
+    /* In accordance to RFC3927 section 2.1:
+     * Keep using the same link local address as much as possible.
+     * Only when there is none or when there was a conflict, select a new one.
+     */
+    if (!ip4_addr_islinklocal(&autoip->llipaddr)) {
+      autoip_create_addr(netif, &(autoip->llipaddr));
+    }
+    autoip->state = AUTOIP_STATE_CHECKING;
+    acd_start(netif, &autoip->acd, autoip->llipaddr);
+  } else {
+    LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
+                ("autoip_start(): already started on netif=%p %c%c%"U16_F"\n",
+                (void *)netif, netif->name[0],
+                 netif->name[1], (u16_t)netif->num));
+  }
+
+  return result;
+}
+
+
+/**
+ * Handle a possible change in the network configuration: link up
+ *
+ * If there is an AutoIP address configured and AutoIP is not in cooperation
+ * with DHCP, start probing for previous address.
+ */
+void
+autoip_network_changed_link_up(struct netif *netif)
+{
+  struct autoip *autoip = netif_autoip_data(netif);
+
+  if (autoip && (autoip->state != AUTOIP_STATE_OFF) && !LWIP_DHCP_AUTOIP_COOP) {
+    LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
+                ("autoip_network_changed_link_up(): start acd\n"));
+    autoip->state = AUTOIP_STATE_CHECKING;
+    /* Start acd check again for the last used address */
+    acd_start(netif, &autoip->acd, autoip->llipaddr);
+  }
+}
+
+/**
+ * Handle a possible change in the network configuration: link down
+ *
+ * If there is an AutoIP address configured and AutoIP is in cooperation
+ * with DHCP, then stop the autoip module. When the link goes up, we do not want
+ * the autoip module to start again. DHCP will initiate autoip when needed.
+ */
+void
+autoip_network_changed_link_down(struct netif *netif)
+{
+  struct autoip *autoip = netif_autoip_data(netif);
+
+  if (autoip && (autoip->state != AUTOIP_STATE_OFF) && LWIP_DHCP_AUTOIP_COOP) {
+    LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
+                ("autoip_network_changed_link_down(): stop autoip\n"));
+    autoip_stop(netif);
+  }
+}
+
+/**
+ * @ingroup autoip
+ * Stop AutoIP client
+ *
+ * @param netif network interface on which stop the AutoIP client
+ */
+err_t
+autoip_stop(struct netif *netif)
+{
+  struct autoip *autoip = netif_autoip_data(netif);
+
+  LWIP_ASSERT_CORE_LOCKED();
+  if (autoip != NULL) {
+    autoip->state = AUTOIP_STATE_OFF;
+    if (ip4_addr_islinklocal(netif_ip4_addr(netif))) {
+      netif_set_addr(netif, IP4_ADDR_ANY4, IP4_ADDR_ANY4, IP4_ADDR_ANY4);
+    }
+    LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,("autoip_stop()\n"));
+  }
+  return ERR_OK;
+}
+
+/** check if AutoIP supplied netif->ip_addr
+ *
+ * @param netif the netif to check
+ * @return 1 if AutoIP supplied netif->ip_addr (state BOUND),
+ *         0 otherwise
+ */
+u8_t
+autoip_supplied_address(struct netif *netif)
+{
+  struct autoip *autoip = netif_autoip_data(netif);
+  return     (autoip != NULL)
+          && (ip4_addr_eq(netif_ip4_addr(netif), &(autoip->llipaddr)))
+          && (autoip->state == AUTOIP_STATE_BOUND);
+}
+
+u8_t
+autoip_accept_packet(struct netif *netif, const ip4_addr_t *addr)
+{
+  struct autoip *autoip = netif_autoip_data(netif);
+  return     (autoip != NULL)
+          && (ip4_addr_eq(addr, &(autoip->llipaddr)))
+          && (autoip->state == AUTOIP_STATE_BOUND);
+}
+
+#endif /* LWIP_IPV4 && LWIP_AUTOIP */

Drivers/LwIP/src/core/ipv4/icmp.c

@@ -0,0 +1,407 @@
+/**
+ * @file
+ * ICMP - Internet Control Message Protocol
+ *
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+
+/* Some ICMP messages should be passed to the transport protocols. This
+   is not implemented. */
+
+#include "lwip/opt.h"
+
+#if LWIP_IPV4 && LWIP_ICMP /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/icmp.h"
+#include "lwip/inet_chksum.h"
+#include "lwip/ip.h"
+#include "lwip/def.h"
+#include "lwip/stats.h"
+
+#include <string.h>
+
+#ifdef LWIP_HOOK_FILENAME
+#include LWIP_HOOK_FILENAME
+#endif
+
+/** Small optimization: set to 0 if incoming PBUF_POOL pbuf always can be
+ * used to modify and send a response packet (and to 1 if this is not the case,
+ * e.g. when link header is stripped off when receiving) */
+#ifndef LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN
+#define LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN 1
+#endif /* LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN */
+
+/* The maximum amount of data from the original packet to return in a dest-unreachable */
+#define ICMP_DEST_UNREACH_DATASIZE 8
+
+static void icmp_send_response(struct pbuf *p, u8_t type, u8_t code);
+
+/**
+ * Processes ICMP input packets, called from ip_input().
+ *
+ * Currently only processes icmp echo requests and sends
+ * out the echo response.
+ *
+ * @param p the icmp echo request packet, p->payload pointing to the icmp header
+ * @param inp the netif on which this packet was received
+ */
+void
+icmp_input(struct pbuf *p, struct netif *inp)
+{
+  u8_t type;
+#ifdef LWIP_DEBUG
+  u8_t code;
+#endif /* LWIP_DEBUG */
+  struct icmp_echo_hdr *iecho;
+  const struct ip_hdr *iphdr_in;
+  u16_t hlen;
+  const ip4_addr_t *src;
+
+  ICMP_STATS_INC(icmp.recv);
+  MIB2_STATS_INC(mib2.icmpinmsgs);
+
+  iphdr_in = ip4_current_header();
+  hlen = IPH_HL_BYTES(iphdr_in);
+  if (hlen < IP_HLEN) {
+    LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: short IP header (%"S16_F" bytes) received\n", hlen));
+    goto lenerr;
+  }
+  if (p->len < sizeof(u16_t) * 2) {
+    LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: short ICMP (%"U16_F" bytes) received\n", p->tot_len));
+    goto lenerr;
+  }
+
+  type = *((u8_t *)p->payload);
+#ifdef LWIP_DEBUG
+  code = *(((u8_t *)p->payload) + 1);
+  /* if debug is enabled but debug statement below is somehow disabled: */
+  LWIP_UNUSED_ARG(code);
+#endif /* LWIP_DEBUG */
+  switch (type) {
+    case ICMP_ER:
+      /* This is OK, echo reply might have been parsed by a raw PCB
+         (as obviously, an echo request has been sent, too). */
+      MIB2_STATS_INC(mib2.icmpinechoreps);
+      break;
+    case ICMP_ECHO:
+      MIB2_STATS_INC(mib2.icmpinechos);
+      src = ip4_current_dest_addr();
+      /* multicast destination address? */
+      if (ip4_addr_ismulticast(ip4_current_dest_addr())) {
+#if LWIP_MULTICAST_PING
+        /* For multicast, use address of receiving interface as source address */
+        src = netif_ip4_addr(inp);
+#else /* LWIP_MULTICAST_PING */
+        LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: Not echoing to multicast pings\n"));
+        goto icmperr;
+#endif /* LWIP_MULTICAST_PING */
+      }
+      /* broadcast destination address? */
+      if (ip4_addr_isbroadcast(ip4_current_dest_addr(), ip_current_netif())) {
+#if LWIP_BROADCAST_PING
+        /* For broadcast, use address of receiving interface as source address */
+        src = netif_ip4_addr(inp);
+#else /* LWIP_BROADCAST_PING */
+        LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: Not echoing to broadcast pings\n"));
+        goto icmperr;
+#endif /* LWIP_BROADCAST_PING */
+      }
+      LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ping\n"));
+      if (p->tot_len < sizeof(struct icmp_echo_hdr)) {
+        LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: bad ICMP echo received\n"));
+        goto lenerr;
+      }
+#if CHECKSUM_CHECK_ICMP
+      IF__NETIF_CHECKSUM_ENABLED(inp, NETIF_CHECKSUM_CHECK_ICMP) {
+        if (inet_chksum_pbuf(p) != 0) {
+          LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: checksum failed for received ICMP echo\n"));
+          pbuf_free(p);
+          ICMP_STATS_INC(icmp.chkerr);
+          MIB2_STATS_INC(mib2.icmpinerrors);
+          return;
+        }
+      }
+#endif
+#if LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN
+      if (pbuf_add_header(p, hlen + PBUF_LINK_HLEN + PBUF_LINK_ENCAPSULATION_HLEN)) {
+        /* p is not big enough to contain link headers
+         * allocate a new one and copy p into it
+         */
+        struct pbuf *r;
+        u16_t alloc_len = (u16_t)(p->tot_len + hlen);
+        if (alloc_len < p->tot_len) {
+          LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: allocating new pbuf failed (tot_len overflow)\n"));
+          goto icmperr;
+        }
+        /* allocate new packet buffer with space for link headers */
+        r = pbuf_alloc(PBUF_LINK, alloc_len, PBUF_RAM);
+        if (r == NULL) {
+          LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: allocating new pbuf failed\n"));
+          goto icmperr;
+        }
+        if (r->len < hlen + sizeof(struct icmp_echo_hdr)) {
+          LWIP_DEBUGF(ICMP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("first pbuf cannot hold the ICMP header\n"));
+          pbuf_free(r);
+          goto icmperr;
+        }
+        /* copy the ip header */
+        MEMCPY(r->payload, iphdr_in, hlen);
+        /* switch r->payload back to icmp header (cannot fail) */
+        if (pbuf_remove_header(r, hlen)) {
+          LWIP_ASSERT("icmp_input: moving r->payload to icmp header failed", 0);
+          pbuf_free(r);
+          goto icmperr;
+        }
+        /* copy the rest of the packet without ip header */
+        if (pbuf_copy(r, p) != ERR_OK) {
+          LWIP_DEBUGF(ICMP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("icmp_input: copying to new pbuf failed\n"));
+          pbuf_free(r);
+          goto icmperr;
+        }
+        /* free the original p */
+        pbuf_free(p);
+        /* we now have an identical copy of p that has room for link headers */
+        p = r;
+      } else {
+        /* restore p->payload to point to icmp header (cannot fail) */
+        if (pbuf_remove_header(p, hlen + PBUF_LINK_HLEN + PBUF_LINK_ENCAPSULATION_HLEN)) {
+          LWIP_ASSERT("icmp_input: restoring original p->payload failed", 0);
+          goto icmperr;
+        }
+      }
+#endif /* LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN */
+      /* At this point, all checks are OK. */
+      /* We generate an answer by switching the dest and src ip addresses,
+       * setting the icmp type to ECHO_RESPONSE and updating the checksum. */
+      iecho = (struct icmp_echo_hdr *)p->payload;
+      if (pbuf_add_header(p, hlen)) {
+        LWIP_DEBUGF(ICMP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("Can't move over header in packet\n"));
+      } else {
+        err_t ret;
+        struct ip_hdr *iphdr = (struct ip_hdr *)p->payload;
+        ip4_addr_copy(iphdr->src, *src);
+        ip4_addr_copy(iphdr->dest, *ip4_current_src_addr());
+        ICMPH_TYPE_SET(iecho, ICMP_ER);
+#if CHECKSUM_GEN_ICMP
+        IF__NETIF_CHECKSUM_ENABLED(inp, NETIF_CHECKSUM_GEN_ICMP) {
+          /* adjust the checksum */
+          if (iecho->chksum > PP_HTONS(0xffffU - (ICMP_ECHO << 8))) {
+            iecho->chksum = (u16_t)(iecho->chksum + PP_HTONS((u16_t)(ICMP_ECHO << 8)) + 1);
+          } else {
+            iecho->chksum = (u16_t)(iecho->chksum + PP_HTONS(ICMP_ECHO << 8));
+          }
+        }
+#if LWIP_CHECKSUM_CTRL_PER_NETIF
+        else {
+          iecho->chksum = 0;
+        }
+#endif /* LWIP_CHECKSUM_CTRL_PER_NETIF */
+#else /* CHECKSUM_GEN_ICMP */
+        iecho->chksum = 0;
+#endif /* CHECKSUM_GEN_ICMP */
+
+        /* Set the correct TTL and recalculate the header checksum. */
+        IPH_TTL_SET(iphdr, ICMP_TTL);
+        IPH_CHKSUM_SET(iphdr, 0);
+#if CHECKSUM_GEN_IP
+        IF__NETIF_CHECKSUM_ENABLED(inp, NETIF_CHECKSUM_GEN_IP) {
+          IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, hlen));
+        }
+#endif /* CHECKSUM_GEN_IP */
+
+        ICMP_STATS_INC(icmp.xmit);
+        /* increase number of messages attempted to send */
+        MIB2_STATS_INC(mib2.icmpoutmsgs);
+        /* increase number of echo replies attempted to send */
+        MIB2_STATS_INC(mib2.icmpoutechoreps);
+
+        /* send an ICMP packet */
+        ret = ip4_output_if(p, src, LWIP_IP_HDRINCL,
+                            ICMP_TTL, 0, IP_PROTO_ICMP, inp);
+        if (ret != ERR_OK) {
+          LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ip_output_if returned an error: %s\n", lwip_strerr(ret)));
+        }
+      }
+      break;
+    default:
+      if (type == ICMP_DUR) {
+        MIB2_STATS_INC(mib2.icmpindestunreachs);
+      } else if (type == ICMP_TE) {
+        MIB2_STATS_INC(mib2.icmpintimeexcds);
+      } else if (type == ICMP_PP) {
+        MIB2_STATS_INC(mib2.icmpinparmprobs);
+      } else if (type == ICMP_SQ) {
+        MIB2_STATS_INC(mib2.icmpinsrcquenchs);
+      } else if (type == ICMP_RD) {
+        MIB2_STATS_INC(mib2.icmpinredirects);
+      } else if (type == ICMP_TS) {
+        MIB2_STATS_INC(mib2.icmpintimestamps);
+      } else if (type == ICMP_TSR) {
+        MIB2_STATS_INC(mib2.icmpintimestampreps);
+      } else if (type == ICMP_AM) {
+        MIB2_STATS_INC(mib2.icmpinaddrmasks);
+      } else if (type == ICMP_AMR) {
+        MIB2_STATS_INC(mib2.icmpinaddrmaskreps);
+      }
+      LWIP_DEBUGF(ICMP_DEBUG, ("icmp_input: ICMP type %"S16_F" code %"S16_F" not supported.\n",
+                               (s16_t)type, (s16_t)code));
+      ICMP_STATS_INC(icmp.proterr);
+      ICMP_STATS_INC(icmp.drop);
+  }
+  pbuf_free(p);
+  return;
+lenerr:
+  pbuf_free(p);
+  ICMP_STATS_INC(icmp.lenerr);
+  MIB2_STATS_INC(mib2.icmpinerrors);
+  return;
+#if LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN || !LWIP_MULTICAST_PING || !LWIP_BROADCAST_PING
+icmperr:
+  pbuf_free(p);
+  ICMP_STATS_INC(icmp.err);
+  MIB2_STATS_INC(mib2.icmpinerrors);
+  return;
+#endif /* LWIP_ICMP_ECHO_CHECK_INPUT_PBUF_LEN || !LWIP_MULTICAST_PING || !LWIP_BROADCAST_PING */
+}
+
+/**
+ * Send an icmp 'destination unreachable' packet, called from ip_input() if
+ * the transport layer protocol is unknown and from udp_input() if the local
+ * port is not bound.
+ *
+ * @param p the input packet for which the 'unreachable' should be sent,
+ *          p->payload pointing to the IP header
+ * @param t type of the 'unreachable' packet
+ */
+void
+icmp_dest_unreach(struct pbuf *p, enum icmp_dur_type t)
+{
+  MIB2_STATS_INC(mib2.icmpoutdestunreachs);
+  icmp_send_response(p, ICMP_DUR, t);
+}
+
+#if IP_FORWARD || IP_REASSEMBLY
+/**
+ * Send a 'time exceeded' packet, called from ip_forward() if TTL is 0.
+ *
+ * @param p the input packet for which the 'time exceeded' should be sent,
+ *          p->payload pointing to the IP header
+ * @param t type of the 'time exceeded' packet
+ */
+void
+icmp_time_exceeded(struct pbuf *p, enum icmp_te_type t)
+{
+  MIB2_STATS_INC(mib2.icmpouttimeexcds);
+  icmp_send_response(p, ICMP_TE, t);
+}
+
+#endif /* IP_FORWARD || IP_REASSEMBLY */
+
+/**
+ * Send an icmp packet in response to an incoming packet.
+ *
+ * @param p the input packet for which the 'unreachable' should be sent,
+ *          p->payload pointing to the IP header
+ * @param type Type of the ICMP header
+ * @param code Code of the ICMP header
+ */
+static void
+icmp_send_response(struct pbuf *p, u8_t type, u8_t code)
+{
+  struct pbuf *q;
+  struct ip_hdr *iphdr;
+  struct icmp_hdr *icmphdr;
+  ip4_addr_t iphdr_src;
+  struct netif *netif;
+  u16_t response_pkt_len;
+
+  /* increase number of messages attempted to send */
+  MIB2_STATS_INC(mib2.icmpoutmsgs);
+
+  /* Keep IP header + up to 8 bytes */
+  response_pkt_len = IP_HLEN + ICMP_DEST_UNREACH_DATASIZE;
+  if (p->tot_len < response_pkt_len) {
+    response_pkt_len = p->tot_len;
+  }
+
+  /* ICMP header + part of original packet */
+  q = pbuf_alloc(PBUF_IP, sizeof(struct icmp_hdr) + response_pkt_len, PBUF_RAM);
+  if (q == NULL) {
+    LWIP_DEBUGF(ICMP_DEBUG, ("icmp_send_response: failed to allocate pbuf for ICMP packet.\n"));
+    MIB2_STATS_INC(mib2.icmpouterrors);
+    return;
+  }
+  LWIP_ASSERT("check that first pbuf can hold icmp message",
+              (q->len >= (sizeof(struct icmp_hdr) + response_pkt_len)));
+
+  iphdr = (struct ip_hdr *)p->payload;
+  LWIP_DEBUGF(ICMP_DEBUG, ("icmp_send_response: Sending ICMP type %02X for packet from ", type));
+  ip4_addr_debug_print_val(ICMP_DEBUG, iphdr->src);
+  LWIP_DEBUGF(ICMP_DEBUG, (" to "));
+  ip4_addr_debug_print_val(ICMP_DEBUG, iphdr->dest);
+  LWIP_DEBUGF(ICMP_DEBUG, ("\n"));
+
+  icmphdr = (struct icmp_hdr *)q->payload;
+  icmphdr->type = type;
+  icmphdr->code = code;
+  icmphdr->data = 0;
+
+  /* copy fields from original packet */
+  pbuf_copy_partial_pbuf(q, p, response_pkt_len, sizeof(struct icmp_hdr));
+
+  ip4_addr_copy(iphdr_src, iphdr->src);
+#ifdef LWIP_HOOK_IP4_ROUTE_SRC
+  {
+    ip4_addr_t iphdr_dst;
+    ip4_addr_copy(iphdr_dst, iphdr->dest);
+    netif = ip4_route_src(&iphdr_dst, &iphdr_src);
+  }
+#else
+  netif = ip4_route(&iphdr_src);
+#endif
+  if (netif != NULL) {
+    /* calculate checksum */
+    icmphdr->chksum = 0;
+#if CHECKSUM_GEN_ICMP
+    IF__NETIF_CHECKSUM_ENABLED(netif, NETIF_CHECKSUM_GEN_ICMP) {
+      icmphdr->chksum = inet_chksum(icmphdr, q->len);
+    }
+#endif
+    ICMP_STATS_INC(icmp.xmit);
+    ip4_output_if(q, NULL, &iphdr_src, ICMP_TTL, 0, IP_PROTO_ICMP, netif);
+  }
+  pbuf_free(q);
+}
+
+#endif /* LWIP_IPV4 && LWIP_ICMP */

Drivers/LwIP/src/core/ipv4/igmp.c

@@ -0,0 +1,801 @@
+/**
+ * @file
+ * IGMP - Internet Group Management Protocol
+ *
+ * @defgroup igmp IGMP
+ * @ingroup ip4
+ * To be called from TCPIP thread
+ */
+
+/*
+ * Copyright (c) 2002 CITEL Technologies Ltd.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of CITEL Technologies Ltd nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY CITEL TECHNOLOGIES AND CONTRIBUTORS ``AS IS''
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL CITEL TECHNOLOGIES OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * This file is a contribution to the lwIP TCP/IP stack.
+ * The Swedish Institute of Computer Science and Adam Dunkels
+ * are specifically granted permission to redistribute this
+ * source code.
+*/
+
+/*-------------------------------------------------------------
+Note 1)
+Although the rfc requires V1 AND V2 capability
+we will only support v2 since now V1 is very old (August 1989)
+V1 can be added if required
+
+a debug print and statistic have been implemented to
+show this up.
+-------------------------------------------------------------
+-------------------------------------------------------------
+Note 2)
+A query for a specific group address (as opposed to ALLHOSTS)
+has now been implemented as I am unsure if it is required
+
+a debug print and statistic have been implemented to
+show this up.
+-------------------------------------------------------------
+-------------------------------------------------------------
+Note 3)
+The router alert rfc 2113 is implemented in outgoing packets
+but not checked rigorously incoming
+-------------------------------------------------------------
+Steve Reynolds
+------------------------------------------------------------*/
+
+/*-----------------------------------------------------------------------------
+ * RFC 988  - Host extensions for IP multicasting                         - V0
+ * RFC 1054 - Host extensions for IP multicasting                         -
+ * RFC 1112 - Host extensions for IP multicasting                         - V1
+ * RFC 2236 - Internet Group Management Protocol, Version 2               - V2  <- this code is based on this RFC (it's the "de facto" standard)
+ * RFC 3376 - Internet Group Management Protocol, Version 3               - V3
+ * RFC 4604 - Using Internet Group Management Protocol Version 3...       - V3+
+ * RFC 2113 - IP Router Alert Option                                      -
+ *----------------------------------------------------------------------------*/
+
+/*-----------------------------------------------------------------------------
+ * Includes
+ *----------------------------------------------------------------------------*/
+
+#include "lwip/opt.h"
+
+#if LWIP_IPV4 && LWIP_IGMP /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/igmp.h"
+#include "lwip/debug.h"
+#include "lwip/def.h"
+#include "lwip/mem.h"
+#include "lwip/ip.h"
+#include "lwip/inet_chksum.h"
+#include "lwip/netif.h"
+#include "lwip/stats.h"
+#include "lwip/prot/igmp.h"
+
+#include <string.h>
+
+static struct igmp_group *igmp_lookup_group(struct netif *ifp, const ip4_addr_t *addr);
+static err_t  igmp_remove_group(struct netif *netif, struct igmp_group *group);
+static void   igmp_timeout(struct netif *netif, struct igmp_group *group);
+static void   igmp_start_timer(struct igmp_group *group, u8_t max_time);
+static void   igmp_delaying_member(struct igmp_group *group, u8_t maxresp);
+static err_t  igmp_ip_output_if(struct pbuf *p, const ip4_addr_t *src, const ip4_addr_t *dest, struct netif *netif);
+static void   igmp_send(struct netif *netif, struct igmp_group *group, u8_t type);
+
+static ip4_addr_t     allsystems;
+static ip4_addr_t     allrouters;
+
+/**
+ * Initialize the IGMP module
+ */
+void
+igmp_init(void)
+{
+  LWIP_DEBUGF(IGMP_DEBUG, ("igmp_init: initializing\n"));
+
+  IP4_ADDR(&allsystems, 224, 0, 0, 1);
+  IP4_ADDR(&allrouters, 224, 0, 0, 2);
+}
+
+/**
+ * Start IGMP processing on interface
+ *
+ * @param netif network interface on which start IGMP processing
+ */
+err_t
+igmp_start(struct netif *netif)
+{
+  struct igmp_group *group;
+
+  LWIP_DEBUGF(IGMP_DEBUG, ("igmp_start: starting IGMP processing on if %p\n", (void *)netif));
+
+  group = igmp_lookup_group(netif, &allsystems);
+
+  if (group != NULL) {
+    group->group_state = IGMP_GROUP_IDLE_MEMBER;
+    group->use++;
+
+    /* Allow the igmp messages at the MAC level */
+    if (netif->igmp_mac_filter != NULL) {
+      LWIP_DEBUGF(IGMP_DEBUG, ("igmp_start: igmp_mac_filter(ADD "));
+      ip4_addr_debug_print_val(IGMP_DEBUG, allsystems);
+      LWIP_DEBUGF(IGMP_DEBUG, (") on if %p\n", (void *)netif));
+      netif->igmp_mac_filter(netif, &allsystems, NETIF_ADD_MAC_FILTER);
+    }
+
+    return ERR_OK;
+  }
+
+  return ERR_MEM;
+}
+
+/**
+ * Stop IGMP processing on interface
+ *
+ * @param netif network interface on which stop IGMP processing
+ */
+err_t
+igmp_stop(struct netif *netif)
+{
+  struct igmp_group *group = netif_igmp_data(netif);
+
+  netif_set_client_data(netif, LWIP_NETIF_CLIENT_DATA_INDEX_IGMP, NULL);
+
+  while (group != NULL) {
+    struct igmp_group *next = group->next; /* avoid use-after-free below */
+
+    /* disable the group at the MAC level */
+    if (netif->igmp_mac_filter != NULL) {
+      LWIP_DEBUGF(IGMP_DEBUG, ("igmp_stop: igmp_mac_filter(DEL "));
+      ip4_addr_debug_print_val(IGMP_DEBUG, group->group_address);
+      LWIP_DEBUGF(IGMP_DEBUG, (") on if %p\n", (void *)netif));
+      netif->igmp_mac_filter(netif, &(group->group_address), NETIF_DEL_MAC_FILTER);
+    }
+
+    /* free group */
+    memp_free(MEMP_IGMP_GROUP, group);
+
+    /* move to "next" */
+    group = next;
+  }
+  return ERR_OK;
+}
+
+/**
+ * Report IGMP memberships for this interface
+ *
+ * @param netif network interface on which report IGMP memberships
+ */
+void
+igmp_report_groups(struct netif *netif)
+{
+  struct igmp_group *group = netif_igmp_data(netif);
+
+  LWIP_DEBUGF(IGMP_DEBUG, ("igmp_report_groups: sending IGMP reports on if %p\n", (void *)netif));
+
+  /* Skip the first group in the list, it is always the allsystems group added in igmp_start() */
+  if (group != NULL) {
+    group = group->next;
+  }
+
+  while (group != NULL) {
+    igmp_delaying_member(group, IGMP_JOIN_DELAYING_MEMBER_TMR);
+    group = group->next;
+  }
+}
+
+/**
+ * Search for a group in the netif's igmp group list
+ *
+ * @param ifp the network interface for which to look
+ * @param addr the group ip address to search for
+ * @return a struct igmp_group* if the group has been found,
+ *         NULL if the group wasn't found.
+ */
+struct igmp_group *
+igmp_lookfor_group(struct netif *ifp, const ip4_addr_t *addr)
+{
+  struct igmp_group *group = netif_igmp_data(ifp);
+
+  while (group != NULL) {
+    if (ip4_addr_eq(&(group->group_address), addr)) {
+      return group;
+    }
+    group = group->next;
+  }
+
+  /* to be clearer, we return NULL here instead of
+   * 'group' (which is also NULL at this point).
+   */
+  return NULL;
+}
+
+/**
+ * Search for a specific igmp group and create a new one if not found-
+ *
+ * @param ifp the network interface for which to look
+ * @param addr the group ip address to search
+ * @return a struct igmp_group*,
+ *         NULL on memory error.
+ */
+static struct igmp_group *
+igmp_lookup_group(struct netif *ifp, const ip4_addr_t *addr)
+{
+  struct igmp_group *group;
+  struct igmp_group *list_head = netif_igmp_data(ifp);
+
+  /* Search if the group already exists */
+  group = igmp_lookfor_group(ifp, addr);
+  if (group != NULL) {
+    /* Group already exists. */
+    return group;
+  }
+
+  /* Group doesn't exist yet, create a new one */
+  group = (struct igmp_group *)memp_malloc(MEMP_IGMP_GROUP);
+  if (group != NULL) {
+    ip4_addr_set(&(group->group_address), addr);
+    group->timer              = 0; /* Not running */
+    group->group_state        = IGMP_GROUP_NON_MEMBER;
+    group->last_reporter_flag = 0;
+    group->use                = 0;
+
+    /* Ensure allsystems group is always first in list */
+    if (list_head == NULL) {
+      /* this is the first entry in linked list */
+      LWIP_ASSERT("igmp_lookup_group: first group must be allsystems",
+                  (ip4_addr_eq(addr, &allsystems) != 0));
+      group->next = NULL;
+      netif_set_client_data(ifp, LWIP_NETIF_CLIENT_DATA_INDEX_IGMP, group);
+    } else {
+      /* append _after_ first entry */
+      LWIP_ASSERT("igmp_lookup_group: all except first group must not be allsystems",
+                  (ip4_addr_eq(addr, &allsystems) == 0));
+      group->next = list_head->next;
+      list_head->next = group;
+    }
+  }
+
+  LWIP_DEBUGF(IGMP_DEBUG, ("igmp_lookup_group: %sallocated a new group with address ", (group ? "" : "impossible to ")));
+  ip4_addr_debug_print(IGMP_DEBUG, addr);
+  LWIP_DEBUGF(IGMP_DEBUG, (" on if %p\n", (void *)ifp));
+
+  return group;
+}
+
+/**
+ * Remove a group from netif's igmp group list, but don't free it yet
+ *
+ * @param group the group to remove from the netif's igmp group list
+ * @return ERR_OK if group was removed from the list, an err_t otherwise
+ */
+static err_t
+igmp_remove_group(struct netif *netif, struct igmp_group *group)
+{
+  err_t err = ERR_OK;
+  struct igmp_group *tmp_group;
+
+  /* Skip the first group in the list, it is always the allsystems group added in igmp_start() */
+  for (tmp_group = netif_igmp_data(netif); tmp_group != NULL; tmp_group = tmp_group->next) {
+    if (tmp_group->next == group) {
+      tmp_group->next = group->next;
+      break;
+    }
+  }
+  /* Group not found in netif's igmp group list */
+  if (tmp_group == NULL) {
+    err = ERR_ARG;
+  }
+
+  return err;
+}
+
+/**
+ * Called from ip_input() if a new IGMP packet is received.
+ *
+ * @param p received igmp packet, p->payload pointing to the igmp header
+ * @param inp network interface on which the packet was received
+ * @param dest destination ip address of the igmp packet
+ */
+void
+igmp_input(struct pbuf *p, struct netif *inp, const ip4_addr_t *dest)
+{
+  struct igmp_msg   *igmp;
+  struct igmp_group *group;
+  struct igmp_group *groupref;
+
+  IGMP_STATS_INC(igmp.recv);
+
+  /* Note that the length CAN be greater than 8 but only 8 are used - All are included in the checksum */
+  if (p->len < IGMP_MINLEN) {
+    pbuf_free(p);
+    IGMP_STATS_INC(igmp.lenerr);
+    LWIP_DEBUGF(IGMP_DEBUG, ("igmp_input: length error\n"));
+    return;
+  }
+
+  LWIP_DEBUGF(IGMP_DEBUG, ("igmp_input: message from "));
+  ip4_addr_debug_print_val(IGMP_DEBUG, ip4_current_header()->src);
+  LWIP_DEBUGF(IGMP_DEBUG, (" to address "));
+  ip4_addr_debug_print_val(IGMP_DEBUG, ip4_current_header()->dest);
+  LWIP_DEBUGF(IGMP_DEBUG, (" on if %p\n", (void *)inp));
+
+  /* Now calculate and check the checksum */
+  igmp = (struct igmp_msg *)p->payload;
+  if (inet_chksum(igmp, p->len)) {
+    pbuf_free(p);
+    IGMP_STATS_INC(igmp.chkerr);
+    LWIP_DEBUGF(IGMP_DEBUG, ("igmp_input: checksum error\n"));
+    return;
+  }
+
+  /* Packet is ok so find an existing group */
+  group = igmp_lookfor_group(inp, dest); /* use the destination IP address of incoming packet */
+
+  /* If group can be found or create... */
+  if (!group) {
+    pbuf_free(p);
+    IGMP_STATS_INC(igmp.drop);
+    LWIP_DEBUGF(IGMP_DEBUG, ("igmp_input: IGMP frame not for us\n"));
+    return;
+  }
+
+  /* NOW ACT ON THE INCOMING MESSAGE TYPE... */
+  switch (igmp->igmp_msgtype) {
+    case IGMP_MEMB_QUERY:
+      /* IGMP_MEMB_QUERY to the "all systems" address ? */
+      if ((ip4_addr_eq(dest, &allsystems)) && ip4_addr_isany(&igmp->igmp_group_address)) {
+        /* THIS IS THE GENERAL QUERY */
+        LWIP_DEBUGF(IGMP_DEBUG, ("igmp_input: General IGMP_MEMB_QUERY on \"ALL SYSTEMS\" address (224.0.0.1) [igmp_maxresp=%i]\n", (int)(igmp->igmp_maxresp)));
+
+        if (igmp->igmp_maxresp == 0) {
+          IGMP_STATS_INC(igmp.rx_v1);
+          LWIP_DEBUGF(IGMP_DEBUG, ("igmp_input: got an all hosts query with time== 0 - this is V1 and not implemented - treat as v2\n"));
+          igmp->igmp_maxresp = IGMP_V1_DELAYING_MEMBER_TMR;
+        } else {
+          IGMP_STATS_INC(igmp.rx_general);
+        }
+
+        groupref = netif_igmp_data(inp);
+
+        /* Do not send messages on the all systems group address! */
+        /* Skip the first group in the list, it is always the allsystems group added in igmp_start() */
+        if (groupref != NULL) {
+          groupref = groupref->next;
+        }
+
+        while (groupref) {
+          igmp_delaying_member(groupref, igmp->igmp_maxresp);
+          groupref = groupref->next;
+        }
+      } else {
+        /* IGMP_MEMB_QUERY to a specific group ? */
+        if (!ip4_addr_isany(&igmp->igmp_group_address)) {
+          LWIP_DEBUGF(IGMP_DEBUG, ("igmp_input: IGMP_MEMB_QUERY to a specific group "));
+          ip4_addr_debug_print_val(IGMP_DEBUG, igmp->igmp_group_address);
+          if (ip4_addr_eq(dest, &allsystems)) {
+            ip4_addr_t groupaddr;
+            LWIP_DEBUGF(IGMP_DEBUG, (" using \"ALL SYSTEMS\" address (224.0.0.1) [igmp_maxresp=%i]\n", (int)(igmp->igmp_maxresp)));
+            /* we first need to re-look for the group since we used dest last time */
+            ip4_addr_copy(groupaddr, igmp->igmp_group_address);
+            group = igmp_lookfor_group(inp, &groupaddr);
+          } else {
+            LWIP_DEBUGF(IGMP_DEBUG, (" with the group address as destination [igmp_maxresp=%i]\n", (int)(igmp->igmp_maxresp)));
+          }
+
+          if (group != NULL) {
+            IGMP_STATS_INC(igmp.rx_group);
+            igmp_delaying_member(group, igmp->igmp_maxresp);
+          } else {
+            IGMP_STATS_INC(igmp.drop);
+          }
+        } else {
+          IGMP_STATS_INC(igmp.proterr);
+        }
+      }
+      break;
+    case IGMP_V2_MEMB_REPORT:
+      LWIP_DEBUGF(IGMP_DEBUG, ("igmp_input: IGMP_V2_MEMB_REPORT\n"));
+      IGMP_STATS_INC(igmp.rx_report);
+      if (group->group_state == IGMP_GROUP_DELAYING_MEMBER) {
+        /* This is on a specific group we have already looked up */
+        group->timer = 0; /* stopped */
+        group->group_state = IGMP_GROUP_IDLE_MEMBER;
+        group->last_reporter_flag = 0;
+      }
+      break;
+    default:
+      LWIP_DEBUGF(IGMP_DEBUG, ("igmp_input: unexpected msg %d in state %d on group %p on if %p\n",
+                               igmp->igmp_msgtype, group->group_state, (void *)&group, (void *)inp));
+      IGMP_STATS_INC(igmp.proterr);
+      break;
+  }
+
+  pbuf_free(p);
+  return;
+}
+
+/**
+ * @ingroup igmp
+ * Join a group on one network interface.
+ *
+ * @param ifaddr ip address of the network interface which should join a new group
+ * @param groupaddr the ip address of the group which to join
+ * @return ERR_OK if group was joined on the netif(s), an err_t otherwise
+ */
+err_t
+igmp_joingroup(const ip4_addr_t *ifaddr, const ip4_addr_t *groupaddr)
+{
+  err_t err = ERR_VAL; /* no matching interface */
+  struct netif *netif;
+
+  LWIP_ASSERT_CORE_LOCKED();
+
+  /* make sure it is multicast address */
+  LWIP_ERROR("igmp_joingroup: attempt to join non-multicast address", ip4_addr_ismulticast(groupaddr), return ERR_VAL;);
+  LWIP_ERROR("igmp_joingroup: attempt to join allsystems address", (!ip4_addr_eq(groupaddr, &allsystems)), return ERR_VAL;);
+
+  /* loop through netif's */
+  NETIF_FOREACH(netif) {
+    /* Should we join this interface ? */
+    if ((netif->flags & NETIF_FLAG_IGMP) && ((ip4_addr_isany(ifaddr) || ip4_addr_eq(netif_ip4_addr(netif), ifaddr)))) {
+      err = igmp_joingroup_netif(netif, groupaddr);
+      if (err != ERR_OK) {
+        /* Return an error even if some network interfaces are joined */
+        /** @todo undo any other netif already joined */
+        return err;
+      }
+    }
+  }
+
+  return err;
+}
+
+/**
+ * @ingroup igmp
+ * Join a group on one network interface.
+ *
+ * @param netif the network interface which should join a new group
+ * @param groupaddr the ip address of the group which to join
+ * @return ERR_OK if group was joined on the netif, an err_t otherwise
+ */
+err_t
+igmp_joingroup_netif(struct netif *netif, const ip4_addr_t *groupaddr)
+{
+  struct igmp_group *group;
+
+  LWIP_ASSERT_CORE_LOCKED();
+
+  /* make sure it is multicast address */
+  LWIP_ERROR("igmp_joingroup_netif: attempt to join non-multicast address", ip4_addr_ismulticast(groupaddr), return ERR_VAL;);
+  LWIP_ERROR("igmp_joingroup_netif: attempt to join allsystems address", (!ip4_addr_eq(groupaddr, &allsystems)), return ERR_VAL;);
+
+  /* make sure it is an igmp-enabled netif */
+  LWIP_ERROR("igmp_joingroup_netif: attempt to join on non-IGMP netif", netif->flags & NETIF_FLAG_IGMP, return ERR_VAL;);
+
+  /* find group or create a new one if not found */
+  group = igmp_lookup_group(netif, groupaddr);
+
+  if (group != NULL) {
+    /* This should create a new group, check the state to make sure */
+    if (group->group_state != IGMP_GROUP_NON_MEMBER) {
+      LWIP_DEBUGF(IGMP_DEBUG, ("igmp_joingroup_netif: join to group not in state IGMP_GROUP_NON_MEMBER\n"));
+    } else {
+      /* OK - it was new group */
+      LWIP_DEBUGF(IGMP_DEBUG, ("igmp_joingroup_netif: join to new group: "));
+      ip4_addr_debug_print(IGMP_DEBUG, groupaddr);
+      LWIP_DEBUGF(IGMP_DEBUG, ("\n"));
+
+      /* If first use of the group, allow the group at the MAC level */
+      if ((group->use == 0) && (netif->igmp_mac_filter != NULL)) {
+        LWIP_DEBUGF(IGMP_DEBUG, ("igmp_joingroup_netif: igmp_mac_filter(ADD "));
+        ip4_addr_debug_print(IGMP_DEBUG, groupaddr);
+        LWIP_DEBUGF(IGMP_DEBUG, (") on if %p\n", (void *)netif));
+        netif->igmp_mac_filter(netif, groupaddr, NETIF_ADD_MAC_FILTER);
+      }
+
+      IGMP_STATS_INC(igmp.tx_join);
+      igmp_send(netif, group, IGMP_V2_MEMB_REPORT);
+
+      igmp_start_timer(group, IGMP_JOIN_DELAYING_MEMBER_TMR);
+
+      /* Need to work out where this timer comes from */
+      group->group_state = IGMP_GROUP_DELAYING_MEMBER;
+    }
+    /* Increment group use */
+    group->use++;
+    /* Join on this interface */
+    return ERR_OK;
+  } else {
+    LWIP_DEBUGF(IGMP_DEBUG, ("igmp_joingroup_netif: Not enough memory to join to group\n"));
+    return ERR_MEM;
+  }
+}
+
+/**
+ * @ingroup igmp
+ * Leave a group on one network interface.
+ *
+ * @param ifaddr ip address of the network interface which should leave a group
+ * @param groupaddr the ip address of the group which to leave
+ * @return ERR_OK if group was left on the netif(s), an err_t otherwise
+ */
+err_t
+igmp_leavegroup(const ip4_addr_t *ifaddr, const ip4_addr_t *groupaddr)
+{
+  err_t err = ERR_VAL; /* no matching interface */
+  struct netif *netif;
+
+  LWIP_ASSERT_CORE_LOCKED();
+
+  /* make sure it is multicast address */
+  LWIP_ERROR("igmp_leavegroup: attempt to leave non-multicast address", ip4_addr_ismulticast(groupaddr), return ERR_VAL;);
+  LWIP_ERROR("igmp_leavegroup: attempt to leave allsystems address", (!ip4_addr_eq(groupaddr, &allsystems)), return ERR_VAL;);
+
+  /* loop through netif's */
+  NETIF_FOREACH(netif) {
+    /* Should we leave this interface ? */
+    if ((netif->flags & NETIF_FLAG_IGMP) && ((ip4_addr_isany(ifaddr) || ip4_addr_eq(netif_ip4_addr(netif), ifaddr)))) {
+      err_t res = igmp_leavegroup_netif(netif, groupaddr);
+      if (err != ERR_OK) {
+        /* Store this result if we have not yet gotten a success */
+        err = res;
+      }
+    }
+  }
+
+  return err;
+}
+
+/**
+ * @ingroup igmp
+ * Leave a group on one network interface.
+ *
+ * @param netif the network interface which should leave a group
+ * @param groupaddr the ip address of the group which to leave
+ * @return ERR_OK if group was left on the netif, an err_t otherwise
+ */
+err_t
+igmp_leavegroup_netif(struct netif *netif, const ip4_addr_t *groupaddr)
+{
+  struct igmp_group *group;
+
+  LWIP_ASSERT_CORE_LOCKED();
+
+  /* make sure it is multicast address */
+  LWIP_ERROR("igmp_leavegroup_netif: attempt to leave non-multicast address", ip4_addr_ismulticast(groupaddr), return ERR_VAL;);
+  LWIP_ERROR("igmp_leavegroup_netif: attempt to leave allsystems address", (!ip4_addr_eq(groupaddr, &allsystems)), return ERR_VAL;);
+
+  /* make sure it is an igmp-enabled netif */
+  LWIP_ERROR("igmp_leavegroup_netif: attempt to leave on non-IGMP netif", netif->flags & NETIF_FLAG_IGMP, return ERR_VAL;);
+
+  /* find group */
+  group = igmp_lookfor_group(netif, groupaddr);
+
+  if (group != NULL) {
+    /* Only send a leave if the flag is set according to the state diagram */
+    LWIP_DEBUGF(IGMP_DEBUG, ("igmp_leavegroup_netif: Leaving group: "));
+    ip4_addr_debug_print(IGMP_DEBUG, groupaddr);
+    LWIP_DEBUGF(IGMP_DEBUG, ("\n"));
+
+    /* If there is no other use of the group */
+    if (group->use <= 1) {
+      /* Remove the group from the list */
+      igmp_remove_group(netif, group);
+
+      /* If we are the last reporter for this group */
+      if (group->last_reporter_flag) {
+        LWIP_DEBUGF(IGMP_DEBUG, ("igmp_leavegroup_netif: sending leaving group\n"));
+        IGMP_STATS_INC(igmp.tx_leave);
+        igmp_send(netif, group, IGMP_LEAVE_GROUP);
+      }
+
+      /* Disable the group at the MAC level */
+      if (netif->igmp_mac_filter != NULL) {
+        LWIP_DEBUGF(IGMP_DEBUG, ("igmp_leavegroup_netif: igmp_mac_filter(DEL "));
+        ip4_addr_debug_print(IGMP_DEBUG, groupaddr);
+        LWIP_DEBUGF(IGMP_DEBUG, (") on if %p\n", (void *)netif));
+        netif->igmp_mac_filter(netif, groupaddr, NETIF_DEL_MAC_FILTER);
+      }
+
+      /* Free group struct */
+      memp_free(MEMP_IGMP_GROUP, group);
+    } else {
+      /* Decrement group use */
+      group->use--;
+    }
+    return ERR_OK;
+  } else {
+    LWIP_DEBUGF(IGMP_DEBUG, ("igmp_leavegroup_netif: not member of group\n"));
+    return ERR_VAL;
+  }
+}
+
+/**
+ * The igmp timer function (both for NO_SYS=1 and =0)
+ * Should be called every IGMP_TMR_INTERVAL milliseconds (100 ms is default).
+ */
+void
+igmp_tmr(void)
+{
+  struct netif *netif;
+
+  NETIF_FOREACH(netif) {
+    struct igmp_group *group = netif_igmp_data(netif);
+
+    while (group != NULL) {
+      if (group->timer > 0) {
+        group->timer--;
+        if (group->timer == 0) {
+          igmp_timeout(netif, group);
+        }
+      }
+      group = group->next;
+    }
+  }
+}
+
+/**
+ * Called if a timeout for one group is reached.
+ * Sends a report for this group.
+ *
+ * @param group an igmp_group for which a timeout is reached
+ */
+static void
+igmp_timeout(struct netif *netif, struct igmp_group *group)
+{
+  /* If the state is IGMP_GROUP_DELAYING_MEMBER then we send a report for this group
+     (unless it is the allsystems group) */
+  if ((group->group_state == IGMP_GROUP_DELAYING_MEMBER) &&
+      (!(ip4_addr_eq(&(group->group_address), &allsystems)))) {
+    LWIP_DEBUGF(IGMP_DEBUG, ("igmp_timeout: report membership for group with address "));
+    ip4_addr_debug_print_val(IGMP_DEBUG, group->group_address);
+    LWIP_DEBUGF(IGMP_DEBUG, (" on if %p\n", (void *)netif));
+
+    group->group_state = IGMP_GROUP_IDLE_MEMBER;
+
+    IGMP_STATS_INC(igmp.tx_report);
+    igmp_send(netif, group, IGMP_V2_MEMB_REPORT);
+  }
+}
+
+/**
+ * Start a timer for an igmp group
+ *
+ * @param group the igmp_group for which to start a timer
+ * @param max_time the time in multiples of IGMP_TMR_INTERVAL (decrease with
+ *        every call to igmp_tmr())
+ */
+static void
+igmp_start_timer(struct igmp_group *group, u8_t max_time)
+{
+#ifdef LWIP_RAND
+  group->timer = (u16_t)(max_time > 2 ? (LWIP_RAND() % max_time) : 1);
+#else /* LWIP_RAND */
+  /* ATTENTION: use this only if absolutely necessary! */
+  group->timer = max_time / 2;
+#endif /* LWIP_RAND */
+
+  if (group->timer == 0) {
+    group->timer = 1;
+  }
+}
+
+/**
+ * Delaying membership report for a group if necessary
+ *
+ * @param group the igmp_group for which "delaying" membership report
+ * @param maxresp query delay
+ */
+static void
+igmp_delaying_member(struct igmp_group *group, u8_t maxresp)
+{
+  if ((group->group_state == IGMP_GROUP_IDLE_MEMBER) ||
+      ((group->group_state == IGMP_GROUP_DELAYING_MEMBER) &&
+       ((group->timer == 0) || (maxresp < group->timer)))) {
+    igmp_start_timer(group, maxresp);
+    group->group_state = IGMP_GROUP_DELAYING_MEMBER;
+  }
+}
+
+
+/**
+ * Sends an IP packet on a network interface. This function constructs the IP header
+ * and calculates the IP header checksum. If the source IP address is NULL,
+ * the IP address of the outgoing network interface is filled in as source address.
+ *
+ * @param p the packet to send (p->payload points to the data, e.g. next
+            protocol header; if dest == LWIP_IP_HDRINCL, p already includes an
+            IP header and p->payload points to that IP header)
+ * @param src the source IP address to send from (if src == IP4_ADDR_ANY, the
+ *         IP  address of the netif used to send is used as source address)
+ * @param dest the destination IP address to send the packet to
+ * @param netif the netif on which to send this packet
+ * @return ERR_OK if the packet was sent OK
+ *         ERR_BUF if p doesn't have enough space for IP/LINK headers
+ *         returns errors returned by netif->output
+ */
+static err_t
+igmp_ip_output_if(struct pbuf *p, const ip4_addr_t *src, const ip4_addr_t *dest, struct netif *netif)
+{
+  /* This is the "router alert" option */
+  u16_t ra[2];
+  ra[0] = PP_HTONS(ROUTER_ALERT);
+  ra[1] = 0x0000; /* Router shall examine packet */
+  IGMP_STATS_INC(igmp.xmit);
+  return ip4_output_if_opt(p, src, dest, IGMP_TTL, 0, IP_PROTO_IGMP, netif, ra, ROUTER_ALERTLEN);
+}
+
+/**
+ * Send an igmp packet to a specific group.
+ *
+ * @param group the group to which to send the packet
+ * @param type the type of igmp packet to send
+ */
+static void
+igmp_send(struct netif *netif, struct igmp_group *group, u8_t type)
+{
+  struct pbuf     *p    = NULL;
+  struct igmp_msg *igmp = NULL;
+  ip4_addr_t   src  = *IP4_ADDR_ANY4;
+  ip4_addr_t  *dest = NULL;
+
+  /* IP header + "router alert" option + IGMP header */
+  p = pbuf_alloc(PBUF_TRANSPORT, IGMP_MINLEN, PBUF_RAM);
+
+  if (p) {
+    igmp = (struct igmp_msg *)p->payload;
+    LWIP_ASSERT("igmp_send: check that first pbuf can hold struct igmp_msg",
+                (p->len >= sizeof(struct igmp_msg)));
+    ip4_addr_copy(src, *netif_ip4_addr(netif));
+
+    if (type == IGMP_V2_MEMB_REPORT) {
+      dest = &(group->group_address);
+      ip4_addr_copy(igmp->igmp_group_address, group->group_address);
+      group->last_reporter_flag = 1; /* Remember we were the last to report */
+    } else {
+      if (type == IGMP_LEAVE_GROUP) {
+        dest = &allrouters;
+        ip4_addr_copy(igmp->igmp_group_address, group->group_address);
+      }
+    }
+
+    if ((type == IGMP_V2_MEMB_REPORT) || (type == IGMP_LEAVE_GROUP)) {
+      igmp->igmp_msgtype  = type;
+      igmp->igmp_maxresp  = 0;
+      igmp->igmp_checksum = 0;
+      igmp->igmp_checksum = inet_chksum(igmp, IGMP_MINLEN);
+
+      igmp_ip_output_if(p, &src, dest, netif);
+    }
+
+    pbuf_free(p);
+  } else {
+    LWIP_DEBUGF(IGMP_DEBUG, ("igmp_send: not enough memory for igmp_send\n"));
+    IGMP_STATS_INC(igmp.memerr);
+  }
+}
+
+#endif /* LWIP_IPV4 && LWIP_IGMP */

Drivers/LwIP/src/core/ipv4/ip4_addr.c

@@ -0,0 +1,323 @@
+/**
+ * @file
+ * This is the IPv4 address tools implementation.
+ *
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+
+#include "lwip/opt.h"
+
+#if LWIP_IPV4
+
+#include "lwip/ip_addr.h"
+#include "lwip/netif.h"
+
+/* used by IP4_ADDR_ANY and IP_ADDR_BROADCAST in ip_addr.h */
+const ip_addr_t ip_addr_any = IPADDR4_INIT(IPADDR_ANY);
+const ip_addr_t ip_addr_broadcast = IPADDR4_INIT(IPADDR_BROADCAST);
+
+/**
+ * Determine if an address is a broadcast address on a network interface
+ *
+ * @param addr address to be checked
+ * @param netif the network interface against which the address is checked
+ * @return returns non-zero if the address is a broadcast address
+ */
+u8_t
+ip4_addr_isbroadcast_u32(u32_t addr, const struct netif *netif)
+{
+  ip4_addr_t ipaddr;
+  ip4_addr_set_u32(&ipaddr, addr);
+
+  /* all ones (broadcast) or all zeroes (old skool broadcast) */
+  if ((~addr == IPADDR_ANY) ||
+      (addr == IPADDR_ANY)) {
+    return 1;
+    /* no broadcast support on this network interface? */
+  } else if ((netif->flags & NETIF_FLAG_BROADCAST) == 0) {
+    /* the given address cannot be a broadcast address
+     * nor can we check against any broadcast addresses */
+    return 0;
+    /* address matches network interface address exactly? => no broadcast */
+  } else if (addr == ip4_addr_get_u32(netif_ip4_addr(netif))) {
+    return 0;
+    /*  on the same (sub) network... */
+  } else if (ip4_addr_net_eq(&ipaddr, netif_ip4_addr(netif), netif_ip4_netmask(netif))
+             /* ...and host identifier bits are all ones? =>... */
+             && ((addr & ~ip4_addr_get_u32(netif_ip4_netmask(netif))) ==
+                 (IPADDR_BROADCAST & ~ip4_addr_get_u32(netif_ip4_netmask(netif))))) {
+    /* => network broadcast address */
+    return 1;
+  } else {
+    return 0;
+  }
+}
+
+/** Checks if a netmask is valid (starting with ones, then only zeros)
+ *
+ * @param netmask the IPv4 netmask to check (in network byte order!)
+ * @return 1 if the netmask is valid, 0 if it is not
+ */
+u8_t
+ip4_addr_netmask_valid(u32_t netmask)
+{
+  u32_t mask;
+  u32_t nm_hostorder = lwip_htonl(netmask);
+
+  /* first, check for the first zero */
+  for (mask = 1UL << 31 ; mask != 0; mask >>= 1) {
+    if ((nm_hostorder & mask) == 0) {
+      break;
+    }
+  }
+  /* then check that there is no one */
+  for (; mask != 0; mask >>= 1) {
+    if ((nm_hostorder & mask) != 0) {
+      /* there is a one after the first zero -> invalid */
+      return 0;
+    }
+  }
+  /* no one after the first zero -> valid */
+  return 1;
+}
+
+/**
+ * Ascii internet address interpretation routine.
+ * The value returned is in network order.
+ *
+ * @param cp IP address in ascii representation (e.g. "127.0.0.1")
+ * @return ip address in network order
+ */
+u32_t
+ipaddr_addr(const char *cp)
+{
+  ip4_addr_t val;
+
+  if (ip4addr_aton(cp, &val)) {
+    return ip4_addr_get_u32(&val);
+  }
+  return (IPADDR_NONE);
+}
+
+/**
+ * Check whether "cp" is a valid ascii representation
+ * of an Internet address and convert to a binary address.
+ * Returns 1 if the address is valid, 0 if not.
+ * This replaces inet_addr, the return value from which
+ * cannot distinguish between failure and a local broadcast address.
+ *
+ * @param cp IP address in ascii representation (e.g. "127.0.0.1")
+ * @param addr pointer to which to save the ip address in network order
+ * @return 1 if cp could be converted to addr, 0 on failure
+ */
+int
+ip4addr_aton(const char *cp, ip4_addr_t *addr)
+{
+  u32_t val;
+  u8_t base;
+  char c;
+  u32_t parts[4];
+  u32_t *pp = parts;
+
+  c = *cp;
+  for (;;) {
+    /*
+     * Collect number up to ``.''.
+     * Values are specified as for C:
+     * 0x=hex, 0=octal, 1-9=decimal.
+     */
+    if (!lwip_isdigit(c)) {
+      return 0;
+    }
+    val = 0;
+    base = 10;
+    if (c == '0') {
+      c = *++cp;
+      if (c == 'x' || c == 'X') {
+        base = 16;
+        c = *++cp;
+      } else {
+        base = 8;
+      }
+    }
+    for (;;) {
+      if (lwip_isdigit(c)) {
+        if((base == 8) && ((u32_t)(c - '0') >= 8))
+          break;
+        val = (val * base) + (u32_t)(c - '0');
+        c = *++cp;
+      } else if (base == 16 && lwip_isxdigit(c)) {
+        val = (val << 4) | (u32_t)(c + 10 - (lwip_islower(c) ? 'a' : 'A'));
+        c = *++cp;
+      } else {
+        break;
+      }
+    }
+    if (c == '.') {
+      /*
+       * Internet format:
+       *  a.b.c.d
+       *  a.b.c   (with c treated as 16 bits)
+       *  a.b (with b treated as 24 bits)
+       */
+      if (pp >= parts + 3) {
+        return 0;
+      }
+      *pp++ = val;
+      c = *++cp;
+    } else {
+      break;
+    }
+  }
+  /*
+   * Check for trailing characters.
+   */
+  if (c != '\0' && !lwip_isspace(c)) {
+    return 0;
+  }
+  /*
+   * Concoct the address according to
+   * the number of parts specified.
+   */
+  switch (pp - parts + 1) {
+
+    case 0:
+      return 0;       /* initial nondigit */
+
+    case 1:             /* a -- 32 bits */
+      break;
+
+    case 2:             /* a.b -- 8.24 bits */
+      if (val > 0xffffffUL) {
+        return 0;
+      }
+      if (parts[0] > 0xff) {
+        return 0;
+      }
+      val |= parts[0] << 24;
+      break;
+
+    case 3:             /* a.b.c -- 8.8.16 bits */
+      if (val > 0xffff) {
+        return 0;
+      }
+      if ((parts[0] > 0xff) || (parts[1] > 0xff)) {
+        return 0;
+      }
+      val |= (parts[0] << 24) | (parts[1] << 16);
+      break;
+
+    case 4:             /* a.b.c.d -- 8.8.8.8 bits */
+      if (val > 0xff) {
+        return 0;
+      }
+      if ((parts[0] > 0xff) || (parts[1] > 0xff) || (parts[2] > 0xff)) {
+        return 0;
+      }
+      val |= (parts[0] << 24) | (parts[1] << 16) | (parts[2] << 8);
+      break;
+    default:
+      LWIP_ASSERT("unhandled", 0);
+      break;
+  }
+  if (addr) {
+    ip4_addr_set_u32(addr, lwip_htonl(val));
+  }
+  return 1;
+}
+
+/**
+ * Convert numeric IP address into decimal dotted ASCII representation.
+ * returns ptr to static buffer; not reentrant!
+ *
+ * @param addr ip address in network order to convert
+ * @return pointer to a global static (!) buffer that holds the ASCII
+ *         representation of addr
+ */
+char *
+ip4addr_ntoa(const ip4_addr_t *addr)
+{
+  static char str[IP4ADDR_STRLEN_MAX];
+  return ip4addr_ntoa_r(addr, str, IP4ADDR_STRLEN_MAX);
+}
+
+/**
+ * Same as ip4addr_ntoa, but reentrant since a user-supplied buffer is used.
+ *
+ * @param addr ip address in network order to convert
+ * @param buf target buffer where the string is stored
+ * @param buflen length of buf
+ * @return either pointer to buf which now holds the ASCII
+ *         representation of addr or NULL if buf was too small
+ */
+char *
+ip4addr_ntoa_r(const ip4_addr_t *addr, char *buf, int buflen)
+{
+  u32_t s_addr;
+  char inv[3];
+  char *rp;
+  u8_t *ap;
+  u8_t rem;
+  u8_t n;
+  u8_t i;
+  int len = 0;
+
+  s_addr = ip4_addr_get_u32(addr);
+
+  rp = buf;
+  ap = (u8_t *)&s_addr;
+  for (n = 0; n < 4; n++) {
+    i = 0;
+    do {
+      rem = *ap % (u8_t)10;
+      *ap /= (u8_t)10;
+      inv[i++] = (char)('0' + rem);
+    } while (*ap);
+    while (i--) {
+      if (len++ >= buflen) {
+        return NULL;
+      }
+      *rp++ = inv[i];
+    }
+    if (len++ >= buflen) {
+      return NULL;
+    }
+    *rp++ = '.';
+    ap++;
+  }
+  *--rp = 0;
+  return buf;
+}
+
+#endif /* LWIP_IPV4 */

Drivers/LwIP/src/core/ipv4/ip4_frag.c

@@ -0,0 +1,894 @@
+/**
+ * @file
+ * This is the IPv4 packet segmentation and reassembly implementation.
+ *
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Jani Monoses <jani@iv.ro>
+ *         Simon Goldschmidt
+ * original reassembly code by Adam Dunkels <adam@sics.se>
+ *
+ */
+
+#include "lwip/opt.h"
+
+#if LWIP_IPV4
+
+#include "lwip/ip4_frag.h"
+#include "lwip/def.h"
+#include "lwip/inet_chksum.h"
+#include "lwip/netif.h"
+#include "lwip/stats.h"
+#include "lwip/icmp.h"
+
+#include <string.h>
+
+#if IP_REASSEMBLY
+/**
+ * The IP reassembly code currently has the following limitations:
+ * - IP header options are not supported
+ * - fragments must not overlap (e.g. due to different routes),
+ *   currently, overlapping or duplicate fragments are thrown away
+ *   if IP_REASS_CHECK_OVERLAP=1 (the default)!
+ *
+ * @todo: work with IP header options
+ */
+
+/** Setting this to 0, you can turn off checking the fragments for overlapping
+ * regions. The code gets a little smaller. Only use this if you know that
+ * overlapping won't occur on your network! */
+#ifndef IP_REASS_CHECK_OVERLAP
+#define IP_REASS_CHECK_OVERLAP 1
+#endif /* IP_REASS_CHECK_OVERLAP */
+
+/** Set to 0 to prevent freeing the oldest datagram when the reassembly buffer is
+ * full (IP_REASS_MAX_PBUFS pbufs are enqueued). The code gets a little smaller.
+ * Datagrams will be freed by timeout only. Especially useful when MEMP_NUM_REASSDATA
+ * is set to 1, so one datagram can be reassembled at a time, only. */
+#ifndef IP_REASS_FREE_OLDEST
+#define IP_REASS_FREE_OLDEST 1
+#endif /* IP_REASS_FREE_OLDEST */
+
+#define IP_REASS_FLAG_LASTFRAG 0x01
+
+#define IP_REASS_VALIDATE_TELEGRAM_FINISHED  1
+#define IP_REASS_VALIDATE_PBUF_QUEUED        0
+#define IP_REASS_VALIDATE_PBUF_DROPPED       -1
+
+/** This is a helper struct which holds the starting
+ * offset and the ending offset of this fragment to
+ * easily chain the fragments.
+ * It has the same packing requirements as the IP header, since it replaces
+ * the IP header in memory in incoming fragments (after copying it) to keep
+ * track of the various fragments. (-> If the IP header doesn't need packing,
+ * this struct doesn't need packing, too.)
+ */
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/bpstruct.h"
+#endif
+PACK_STRUCT_BEGIN
+struct ip_reass_helper {
+  PACK_STRUCT_FIELD(struct pbuf *next_pbuf);
+  PACK_STRUCT_FIELD(u16_t start);
+  PACK_STRUCT_FIELD(u16_t end);
+} PACK_STRUCT_STRUCT;
+PACK_STRUCT_END
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/epstruct.h"
+#endif
+
+#define IP_ADDRESSES_AND_ID_MATCH(iphdrA, iphdrB)  \
+  (ip4_addr_eq(&(iphdrA)->src, &(iphdrB)->src) && \
+   ip4_addr_eq(&(iphdrA)->dest, &(iphdrB)->dest) && \
+   IPH_ID(iphdrA) == IPH_ID(iphdrB)) ? 1 : 0
+
+/* global variables */
+static struct ip_reassdata *reassdatagrams;
+static u16_t ip_reass_pbufcount;
+
+/* function prototypes */
+static void ip_reass_dequeue_datagram(struct ip_reassdata *ipr, struct ip_reassdata *prev);
+static int ip_reass_free_complete_datagram(struct ip_reassdata *ipr, struct ip_reassdata *prev);
+
+/**
+ * Reassembly timer base function
+ * for both NO_SYS == 0 and 1 (!).
+ *
+ * Should be called every 1000 msec (defined by IP_TMR_INTERVAL).
+ */
+void
+ip_reass_tmr(void)
+{
+  struct ip_reassdata *r, *prev = NULL;
+
+  r = reassdatagrams;
+  while (r != NULL) {
+    /* Decrement the timer. Once it reaches 0,
+     * clean up the incomplete fragment assembly */
+    if (r->timer > 0) {
+      r->timer--;
+      LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_reass_tmr: timer dec %"U16_F"\n", (u16_t)r->timer));
+      prev = r;
+      r = r->next;
+    } else {
+      /* reassembly timed out */
+      struct ip_reassdata *tmp;
+      LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_reass_tmr: timer timed out\n"));
+      tmp = r;
+      /* get the next pointer before freeing */
+      r = r->next;
+      /* free the helper struct and all enqueued pbufs */
+      ip_reass_free_complete_datagram(tmp, prev);
+    }
+  }
+}
+
+/**
+ * Free a datagram (struct ip_reassdata) and all its pbufs.
+ * Updates the total count of enqueued pbufs (ip_reass_pbufcount),
+ * SNMP counters and sends an ICMP time exceeded packet.
+ *
+ * @param ipr datagram to free
+ * @param prev the previous datagram in the linked list
+ * @return the number of pbufs freed
+ */
+static int
+ip_reass_free_complete_datagram(struct ip_reassdata *ipr, struct ip_reassdata *prev)
+{
+  u16_t pbufs_freed = 0;
+  u16_t clen;
+  struct pbuf *p;
+  struct ip_reass_helper *iprh;
+
+  LWIP_ASSERT("prev != ipr", prev != ipr);
+  if (prev != NULL) {
+    LWIP_ASSERT("prev->next == ipr", prev->next == ipr);
+  }
+
+  MIB2_STATS_INC(mib2.ipreasmfails);
+#if LWIP_ICMP
+  iprh = (struct ip_reass_helper *)ipr->p->payload;
+  if (iprh->start == 0) {
+    /* The first fragment was received, send ICMP time exceeded. */
+    /* First, de-queue the first pbuf from r->p. */
+    p = ipr->p;
+    ipr->p = iprh->next_pbuf;
+    /* Then, copy the original header into it. */
+    SMEMCPY(p->payload, &ipr->iphdr, IP_HLEN);
+    icmp_time_exceeded(p, ICMP_TE_FRAG);
+    clen = pbuf_clen(p);
+    LWIP_ASSERT("pbufs_freed + clen <= 0xffff", pbufs_freed + clen <= 0xffff);
+    pbufs_freed = (u16_t)(pbufs_freed + clen);
+    pbuf_free(p);
+  }
+#endif /* LWIP_ICMP */
+
+  /* First, free all received pbufs.  The individual pbufs need to be released
+     separately as they have not yet been chained */
+  p = ipr->p;
+  while (p != NULL) {
+    struct pbuf *pcur;
+    iprh = (struct ip_reass_helper *)p->payload;
+    pcur = p;
+    /* get the next pointer before freeing */
+    p = iprh->next_pbuf;
+    clen = pbuf_clen(pcur);
+    LWIP_ASSERT("pbufs_freed + clen <= 0xffff", pbufs_freed + clen <= 0xffff);
+    pbufs_freed = (u16_t)(pbufs_freed + clen);
+    pbuf_free(pcur);
+  }
+  /* Then, unchain the struct ip_reassdata from the list and free it. */
+  ip_reass_dequeue_datagram(ipr, prev);
+  LWIP_ASSERT("ip_reass_pbufcount >= pbufs_freed", ip_reass_pbufcount >= pbufs_freed);
+  ip_reass_pbufcount = (u16_t)(ip_reass_pbufcount - pbufs_freed);
+
+  return pbufs_freed;
+}
+
+#if IP_REASS_FREE_OLDEST
+/**
+ * Free the oldest datagram to make room for enqueueing new fragments.
+ * The datagram 'fraghdr' belongs to is not freed!
+ *
+ * @param fraghdr IP header of the current fragment
+ * @param pbufs_needed number of pbufs needed to enqueue
+ *        (used for freeing other datagrams if not enough space)
+ * @return the number of pbufs freed
+ */
+static int
+ip_reass_remove_oldest_datagram(struct ip_hdr *fraghdr, int pbufs_needed)
+{
+  /* @todo Can't we simply remove the last datagram in the
+   *       linked list behind reassdatagrams?
+   */
+  struct ip_reassdata *r, *oldest, *prev, *oldest_prev;
+  int pbufs_freed = 0, pbufs_freed_current;
+  int other_datagrams;
+
+  /* Free datagrams until being allowed to enqueue 'pbufs_needed' pbufs,
+   * but don't free the datagram that 'fraghdr' belongs to! */
+  do {
+    oldest = NULL;
+    prev = NULL;
+    oldest_prev = NULL;
+    other_datagrams = 0;
+    r = reassdatagrams;
+    while (r != NULL) {
+      if (!IP_ADDRESSES_AND_ID_MATCH(&r->iphdr, fraghdr)) {
+        /* Not the same datagram as fraghdr */
+        other_datagrams++;
+        if (oldest == NULL) {
+          oldest = r;
+          oldest_prev = prev;
+        } else if (r->timer <= oldest->timer) {
+          /* older than the previous oldest */
+          oldest = r;
+          oldest_prev = prev;
+        }
+      }
+      if (r->next != NULL) {
+        prev = r;
+      }
+      r = r->next;
+    }
+    if (oldest != NULL) {
+      pbufs_freed_current = ip_reass_free_complete_datagram(oldest, oldest_prev);
+      pbufs_freed += pbufs_freed_current;
+    }
+  } while ((pbufs_freed < pbufs_needed) && (other_datagrams > 1));
+  return pbufs_freed;
+}
+#endif /* IP_REASS_FREE_OLDEST */
+
+/**
+ * Enqueues a new fragment into the fragment queue
+ * @param fraghdr points to the new fragments IP hdr
+ * @param clen number of pbufs needed to enqueue (used for freeing other datagrams if not enough space)
+ * @return A pointer to the queue location into which the fragment was enqueued
+ */
+static struct ip_reassdata *
+ip_reass_enqueue_new_datagram(struct ip_hdr *fraghdr, int clen)
+{
+  struct ip_reassdata *ipr;
+#if ! IP_REASS_FREE_OLDEST
+  LWIP_UNUSED_ARG(clen);
+#endif
+
+  /* No matching previous fragment found, allocate a new reassdata struct */
+  ipr = (struct ip_reassdata *)memp_malloc(MEMP_REASSDATA);
+  if (ipr == NULL) {
+#if IP_REASS_FREE_OLDEST
+    if (ip_reass_remove_oldest_datagram(fraghdr, clen) >= clen) {
+      ipr = (struct ip_reassdata *)memp_malloc(MEMP_REASSDATA);
+    }
+    if (ipr == NULL)
+#endif /* IP_REASS_FREE_OLDEST */
+    {
+      IPFRAG_STATS_INC(ip_frag.memerr);
+      LWIP_DEBUGF(IP_REASS_DEBUG, ("Failed to alloc reassdata struct\n"));
+      return NULL;
+    }
+  }
+  memset(ipr, 0, sizeof(struct ip_reassdata));
+  ipr->timer = IP_REASS_MAXAGE;
+
+  /* enqueue the new structure to the front of the list */
+  ipr->next = reassdatagrams;
+  reassdatagrams = ipr;
+  /* copy the ip header for later tests and input */
+  /* @todo: no ip options supported? */
+  SMEMCPY(&(ipr->iphdr), fraghdr, IP_HLEN);
+  return ipr;
+}
+
+/**
+ * Dequeues a datagram from the datagram queue. Doesn't deallocate the pbufs.
+ * @param ipr points to the queue entry to dequeue
+ */
+static void
+ip_reass_dequeue_datagram(struct ip_reassdata *ipr, struct ip_reassdata *prev)
+{
+  /* dequeue the reass struct  */
+  if (reassdatagrams == ipr) {
+    /* it was the first in the list */
+    reassdatagrams = ipr->next;
+  } else {
+    /* it wasn't the first, so it must have a valid 'prev' */
+    LWIP_ASSERT("sanity check linked list", prev != NULL);
+    prev->next = ipr->next;
+  }
+
+  /* now we can free the ip_reassdata struct */
+  memp_free(MEMP_REASSDATA, ipr);
+}
+
+/**
+ * Chain a new pbuf into the pbuf list that composes the datagram.  The pbuf list
+ * will grow over time as  new pbufs are rx.
+ * Also checks that the datagram passes basic continuity checks (if the last
+ * fragment was received at least once).
+ * @param ipr points to the reassembly state
+ * @param new_p points to the pbuf for the current fragment
+ * @param is_last is 1 if this pbuf has MF==0 (ipr->flags not updated yet)
+ * @return see IP_REASS_VALIDATE_* defines
+ */
+static int
+ip_reass_chain_frag_into_datagram_and_validate(struct ip_reassdata *ipr, struct pbuf *new_p, int is_last)
+{
+  struct ip_reass_helper *iprh, *iprh_tmp, *iprh_prev = NULL;
+  struct pbuf *q;
+  u16_t offset, len;
+  u8_t hlen;
+  struct ip_hdr *fraghdr;
+  int valid = 1;
+
+  /* Extract length and fragment offset from current fragment */
+  fraghdr = (struct ip_hdr *)new_p->payload;
+  len = lwip_ntohs(IPH_LEN(fraghdr));
+  hlen = IPH_HL_BYTES(fraghdr);
+  if (hlen > len) {
+    /* invalid datagram */
+    return IP_REASS_VALIDATE_PBUF_DROPPED;
+  }
+  len = (u16_t)(len - hlen);
+  offset = IPH_OFFSET_BYTES(fraghdr);
+
+  /* overwrite the fragment's ip header from the pbuf with our helper struct,
+   * and setup the embedded helper structure. */
+  /* make sure the struct ip_reass_helper fits into the IP header */
+  LWIP_ASSERT("sizeof(struct ip_reass_helper) <= IP_HLEN",
+              sizeof(struct ip_reass_helper) <= IP_HLEN);
+  iprh = (struct ip_reass_helper *)new_p->payload;
+  iprh->next_pbuf = NULL;
+  iprh->start = offset;
+  iprh->end = (u16_t)(offset + len);
+  if (iprh->end < offset) {
+    /* u16_t overflow, cannot handle this */
+    return IP_REASS_VALIDATE_PBUF_DROPPED;
+  }
+
+  /* Iterate through until we either get to the end of the list (append),
+   * or we find one with a larger offset (insert). */
+  for (q = ipr->p; q != NULL;) {
+    iprh_tmp = (struct ip_reass_helper *)q->payload;
+    if (iprh->start < iprh_tmp->start) {
+      /* the new pbuf should be inserted before this */
+      iprh->next_pbuf = q;
+      if (iprh_prev != NULL) {
+        /* not the fragment with the lowest offset */
+#if IP_REASS_CHECK_OVERLAP
+        if ((iprh->start < iprh_prev->end) || (iprh->end > iprh_tmp->start)) {
+          /* fragment overlaps with previous or following, throw away */
+          return IP_REASS_VALIDATE_PBUF_DROPPED;
+        }
+#endif /* IP_REASS_CHECK_OVERLAP */
+        iprh_prev->next_pbuf = new_p;
+        if (iprh_prev->end != iprh->start) {
+          /* There is a fragment missing between the current
+           * and the previous fragment */
+          valid = 0;
+        }
+      } else {
+#if IP_REASS_CHECK_OVERLAP
+        if (iprh->end > iprh_tmp->start) {
+          /* fragment overlaps with following, throw away */
+          return IP_REASS_VALIDATE_PBUF_DROPPED;
+        }
+#endif /* IP_REASS_CHECK_OVERLAP */
+        /* fragment with the lowest offset */
+        ipr->p = new_p;
+      }
+      break;
+    } else if (iprh->start == iprh_tmp->start) {
+      /* received the same datagram twice: no need to keep the datagram */
+      return IP_REASS_VALIDATE_PBUF_DROPPED;
+#if IP_REASS_CHECK_OVERLAP
+    } else if (iprh->start < iprh_tmp->end) {
+      /* overlap: no need to keep the new datagram */
+      return IP_REASS_VALIDATE_PBUF_DROPPED;
+#endif /* IP_REASS_CHECK_OVERLAP */
+    } else {
+      /* Check if the fragments received so far have no holes. */
+      if (iprh_prev != NULL) {
+        if (iprh_prev->end != iprh_tmp->start) {
+          /* There is a fragment missing between the current
+           * and the previous fragment */
+          valid = 0;
+        }
+      }
+    }
+    q = iprh_tmp->next_pbuf;
+    iprh_prev = iprh_tmp;
+  }
+
+  /* If q is NULL, then we made it to the end of the list. Determine what to do now */
+  if (q == NULL) {
+    if (iprh_prev != NULL) {
+      /* this is (for now), the fragment with the highest offset:
+       * chain it to the last fragment */
+#if IP_REASS_CHECK_OVERLAP
+      LWIP_ASSERT("check fragments don't overlap", iprh_prev->end <= iprh->start);
+#endif /* IP_REASS_CHECK_OVERLAP */
+      iprh_prev->next_pbuf = new_p;
+      if (iprh_prev->end != iprh->start) {
+        valid = 0;
+      }
+    } else {
+#if IP_REASS_CHECK_OVERLAP
+      LWIP_ASSERT("no previous fragment, this must be the first fragment!",
+                  ipr->p == NULL);
+#endif /* IP_REASS_CHECK_OVERLAP */
+      /* this is the first fragment we ever received for this ip datagram */
+      ipr->p = new_p;
+    }
+  }
+
+  /* At this point, the validation part begins: */
+  /* If we already received the last fragment */
+  if (is_last || ((ipr->flags & IP_REASS_FLAG_LASTFRAG) != 0)) {
+    /* and had no holes so far */
+    if (valid) {
+      /* then check if the rest of the fragments is here */
+      /* Check if the queue starts with the first datagram */
+      if ((ipr->p == NULL) || (((struct ip_reass_helper *)ipr->p->payload)->start != 0)) {
+        valid = 0;
+      } else {
+        /* and check that there are no holes after this datagram */
+        iprh_prev = iprh;
+        q = iprh->next_pbuf;
+        while (q != NULL) {
+          iprh = (struct ip_reass_helper *)q->payload;
+          if (iprh_prev->end != iprh->start) {
+            valid = 0;
+            break;
+          }
+          iprh_prev = iprh;
+          q = iprh->next_pbuf;
+        }
+        /* if still valid, all fragments are received
+         * (because to the MF==0 already arrived */
+        if (valid) {
+          LWIP_ASSERT("sanity check", ipr->p != NULL);
+          LWIP_ASSERT("sanity check",
+                      ((struct ip_reass_helper *)ipr->p->payload) != iprh);
+          LWIP_ASSERT("validate_datagram:next_pbuf!=NULL",
+                      iprh->next_pbuf == NULL);
+        }
+      }
+    }
+    /* If valid is 0 here, there are some fragments missing in the middle
+     * (since MF == 0 has already arrived). Such datagrams simply time out if
+     * no more fragments are received... */
+    return valid ? IP_REASS_VALIDATE_TELEGRAM_FINISHED : IP_REASS_VALIDATE_PBUF_QUEUED;
+  }
+  /* If we come here, not all fragments were received, yet! */
+  return IP_REASS_VALIDATE_PBUF_QUEUED; /* not yet valid! */
+}
+
+/**
+ * Reassembles incoming IP fragments into an IP datagram.
+ *
+ * @param p points to a pbuf chain of the fragment
+ * @return NULL if reassembly is incomplete, ? otherwise
+ */
+struct pbuf *
+ip4_reass(struct pbuf *p)
+{
+  struct pbuf *r;
+  struct ip_hdr *fraghdr;
+  struct ip_reassdata *ipr;
+  struct ip_reass_helper *iprh;
+  u16_t offset, len, clen;
+  u8_t hlen;
+  int valid;
+  int is_last;
+
+  IPFRAG_STATS_INC(ip_frag.recv);
+  MIB2_STATS_INC(mib2.ipreasmreqds);
+
+  fraghdr = (struct ip_hdr *)p->payload;
+
+  if (IPH_HL_BYTES(fraghdr) != IP_HLEN) {
+    LWIP_DEBUGF(IP_REASS_DEBUG, ("ip4_reass: IP options currently not supported!\n"));
+    IPFRAG_STATS_INC(ip_frag.err);
+    goto nullreturn;
+  }
+
+  offset = IPH_OFFSET_BYTES(fraghdr);
+  len = lwip_ntohs(IPH_LEN(fraghdr));
+  hlen = IPH_HL_BYTES(fraghdr);
+  if (hlen > len) {
+    /* invalid datagram */
+    goto nullreturn;
+  }
+  len = (u16_t)(len - hlen);
+
+  /* Check if we are allowed to enqueue more datagrams. */
+  clen = pbuf_clen(p);
+  if ((ip_reass_pbufcount + clen) > IP_REASS_MAX_PBUFS) {
+#if IP_REASS_FREE_OLDEST
+    if (!ip_reass_remove_oldest_datagram(fraghdr, clen) ||
+        ((ip_reass_pbufcount + clen) > IP_REASS_MAX_PBUFS))
+#endif /* IP_REASS_FREE_OLDEST */
+    {
+      /* No datagram could be freed and still too many pbufs enqueued */
+      LWIP_DEBUGF(IP_REASS_DEBUG, ("ip4_reass: Overflow condition: pbufct=%d, clen=%d, MAX=%d\n",
+                                   ip_reass_pbufcount, clen, IP_REASS_MAX_PBUFS));
+      IPFRAG_STATS_INC(ip_frag.memerr);
+      /* @todo: send ICMP time exceeded here? */
+      /* drop this pbuf */
+      goto nullreturn;
+    }
+  }
+
+  /* Look for the datagram the fragment belongs to in the current datagram queue,
+   * remembering the previous in the queue for later dequeueing. */
+  for (ipr = reassdatagrams; ipr != NULL; ipr = ipr->next) {
+    /* Check if the incoming fragment matches the one currently present
+       in the reassembly buffer. If so, we proceed with copying the
+       fragment into the buffer. */
+    if (IP_ADDRESSES_AND_ID_MATCH(&ipr->iphdr, fraghdr)) {
+      LWIP_DEBUGF(IP_REASS_DEBUG, ("ip4_reass: matching previous fragment ID=%"X16_F"\n",
+                                   lwip_ntohs(IPH_ID(fraghdr))));
+      IPFRAG_STATS_INC(ip_frag.cachehit);
+      break;
+    }
+  }
+
+  if (ipr == NULL) {
+    /* Enqueue a new datagram into the datagram queue */
+    ipr = ip_reass_enqueue_new_datagram(fraghdr, clen);
+    /* Bail if unable to enqueue */
+    if (ipr == NULL) {
+      goto nullreturn;
+    }
+  } else {
+    if (((lwip_ntohs(IPH_OFFSET(fraghdr)) & IP_OFFMASK) == 0) &&
+        ((lwip_ntohs(IPH_OFFSET(&ipr->iphdr)) & IP_OFFMASK) != 0)) {
+      /* ipr->iphdr is not the header from the first fragment, but fraghdr is
+       * -> copy fraghdr into ipr->iphdr since we want to have the header
+       * of the first fragment (for ICMP time exceeded and later, for copying
+       * all options, if supported)*/
+      SMEMCPY(&ipr->iphdr, fraghdr, IP_HLEN);
+    }
+  }
+
+  /* At this point, we have either created a new entry or pointing
+   * to an existing one */
+
+  /* check for 'no more fragments', and update queue entry*/
+  is_last = (IPH_OFFSET(fraghdr) & PP_NTOHS(IP_MF)) == 0;
+  if (is_last) {
+    u16_t datagram_len = (u16_t)(offset + len);
+    if ((datagram_len < offset) || (datagram_len > (0xFFFF - IP_HLEN))) {
+      /* u16_t overflow, cannot handle this */
+      goto nullreturn_ipr;
+    }
+  }
+  /* find the right place to insert this pbuf */
+  /* @todo: trim pbufs if fragments are overlapping */
+  valid = ip_reass_chain_frag_into_datagram_and_validate(ipr, p, is_last);
+  if (valid == IP_REASS_VALIDATE_PBUF_DROPPED) {
+    goto nullreturn_ipr;
+  }
+  /* if we come here, the pbuf has been enqueued */
+
+  /* Track the current number of pbufs current 'in-flight', in order to limit
+     the number of fragments that may be enqueued at any one time
+     (overflow checked by testing against IP_REASS_MAX_PBUFS) */
+  ip_reass_pbufcount = (u16_t)(ip_reass_pbufcount + clen);
+  if (is_last) {
+    u16_t datagram_len = (u16_t)(offset + len);
+    ipr->datagram_len = datagram_len;
+    ipr->flags |= IP_REASS_FLAG_LASTFRAG;
+    LWIP_DEBUGF(IP_REASS_DEBUG,
+                ("ip4_reass: last fragment seen, total len %"S16_F"\n",
+                 ipr->datagram_len));
+  }
+
+  if (valid == IP_REASS_VALIDATE_TELEGRAM_FINISHED) {
+    struct ip_reassdata *ipr_prev;
+    /* the totally last fragment (flag more fragments = 0) was received at least
+     * once AND all fragments are received */
+    u16_t datagram_len = (u16_t)(ipr->datagram_len + IP_HLEN);
+
+    /* save the second pbuf before copying the header over the pointer */
+    r = ((struct ip_reass_helper *)ipr->p->payload)->next_pbuf;
+
+    /* copy the original ip header back to the first pbuf */
+    fraghdr = (struct ip_hdr *)(ipr->p->payload);
+    SMEMCPY(fraghdr, &ipr->iphdr, IP_HLEN);
+    IPH_LEN_SET(fraghdr, lwip_htons(datagram_len));
+    IPH_OFFSET_SET(fraghdr, 0);
+    IPH_CHKSUM_SET(fraghdr, 0);
+    /* @todo: do we need to set/calculate the correct checksum? */
+#if CHECKSUM_GEN_IP
+    IF__NETIF_CHECKSUM_ENABLED(ip_current_input_netif(), NETIF_CHECKSUM_GEN_IP) {
+      IPH_CHKSUM_SET(fraghdr, inet_chksum(fraghdr, IP_HLEN));
+    }
+#endif /* CHECKSUM_GEN_IP */
+
+    p = ipr->p;
+
+    /* chain together the pbufs contained within the reass_data list. */
+    while (r != NULL) {
+      iprh = (struct ip_reass_helper *)r->payload;
+
+      /* hide the ip header for every succeeding fragment */
+      pbuf_remove_header(r, IP_HLEN);
+      pbuf_cat(p, r);
+      r = iprh->next_pbuf;
+    }
+
+    /* find the previous entry in the linked list */
+    if (ipr == reassdatagrams) {
+      ipr_prev = NULL;
+    } else {
+      for (ipr_prev = reassdatagrams; ipr_prev != NULL; ipr_prev = ipr_prev->next) {
+        if (ipr_prev->next == ipr) {
+          break;
+        }
+      }
+    }
+
+    /* release the sources allocate for the fragment queue entry */
+    ip_reass_dequeue_datagram(ipr, ipr_prev);
+
+    /* and adjust the number of pbufs currently queued for reassembly. */
+    clen = pbuf_clen(p);
+    LWIP_ASSERT("ip_reass_pbufcount >= clen", ip_reass_pbufcount >= clen);
+    ip_reass_pbufcount = (u16_t)(ip_reass_pbufcount - clen);
+
+    MIB2_STATS_INC(mib2.ipreasmoks);
+
+    /* Return the pbuf chain */
+    return p;
+  }
+  /* the datagram is not (yet?) reassembled completely */
+  LWIP_DEBUGF(IP_REASS_DEBUG, ("ip_reass_pbufcount: %d out\n", ip_reass_pbufcount));
+  return NULL;
+
+nullreturn_ipr:
+  LWIP_ASSERT("ipr != NULL", ipr != NULL);
+  if (ipr->p == NULL) {
+    /* dropped pbuf after creating a new datagram entry: remove the entry, too */
+    LWIP_ASSERT("not firstalthough just enqueued", ipr == reassdatagrams);
+    ip_reass_dequeue_datagram(ipr, NULL);
+  }
+
+nullreturn:
+  LWIP_DEBUGF(IP_REASS_DEBUG, ("ip4_reass: nullreturn\n"));
+  IPFRAG_STATS_INC(ip_frag.drop);
+  pbuf_free(p);
+  return NULL;
+}
+#endif /* IP_REASSEMBLY */
+
+#if IP_FRAG
+#if !LWIP_NETIF_TX_SINGLE_PBUF
+/** Allocate a new struct pbuf_custom_ref */
+static struct pbuf_custom_ref *
+ip_frag_alloc_pbuf_custom_ref(void)
+{
+  return (struct pbuf_custom_ref *)memp_malloc(MEMP_FRAG_PBUF);
+}
+
+/** Free a struct pbuf_custom_ref */
+static void
+ip_frag_free_pbuf_custom_ref(struct pbuf_custom_ref *p)
+{
+  LWIP_ASSERT("p != NULL", p != NULL);
+  memp_free(MEMP_FRAG_PBUF, p);
+}
+
+/** Free-callback function to free a 'struct pbuf_custom_ref', called by
+ * pbuf_free. */
+static void
+ipfrag_free_pbuf_custom(struct pbuf *p)
+{
+  struct pbuf_custom_ref *pcr = (struct pbuf_custom_ref *)p;
+  LWIP_ASSERT("pcr != NULL", pcr != NULL);
+  LWIP_ASSERT("pcr == p", (void *)pcr == (void *)p);
+  if (pcr->original != NULL) {
+    pbuf_free(pcr->original);
+  }
+  ip_frag_free_pbuf_custom_ref(pcr);
+}
+#endif /* !LWIP_NETIF_TX_SINGLE_PBUF */
+
+/**
+ * Fragment an IP datagram if too large for the netif.
+ *
+ * Chop the datagram in MTU sized chunks and send them in order
+ * by pointing PBUF_REFs into p.
+ *
+ * @param p ip packet to send
+ * @param netif the netif on which to send
+ * @param dest destination ip address to which to send
+ *
+ * @return ERR_OK if sent successfully, err_t otherwise
+ */
+err_t
+ip4_frag(struct pbuf *p, struct netif *netif, const ip4_addr_t *dest)
+{
+  struct pbuf *rambuf;
+#if !LWIP_NETIF_TX_SINGLE_PBUF
+  struct pbuf *newpbuf;
+  u16_t newpbuflen = 0;
+  u16_t left_to_copy;
+#endif
+  struct ip_hdr *original_iphdr;
+  struct ip_hdr *iphdr;
+  const u16_t nfb = (u16_t)((netif->mtu - IP_HLEN) / 8);
+  u16_t left, fragsize;
+  u16_t ofo;
+  int last;
+  u16_t poff = IP_HLEN;
+  u16_t tmp;
+  int mf_set;
+
+  original_iphdr = (struct ip_hdr *)p->payload;
+  iphdr = original_iphdr;
+  if (IPH_HL_BYTES(iphdr) != IP_HLEN) {
+    /* ip4_frag() does not support IP options */
+    return ERR_VAL;
+  }
+  LWIP_ERROR("ip4_frag(): pbuf too short", p->len >= IP_HLEN, return ERR_VAL);
+
+  /* Save original offset */
+  tmp = lwip_ntohs(IPH_OFFSET(iphdr));
+  ofo = tmp & IP_OFFMASK;
+  /* already fragmented? if so, the last fragment we create must have MF, too */
+  mf_set = tmp & IP_MF;
+
+  left = (u16_t)(p->tot_len - IP_HLEN);
+
+  while (left) {
+    /* Fill this fragment */
+    fragsize = LWIP_MIN(left, (u16_t)(nfb * 8));
+
+#if LWIP_NETIF_TX_SINGLE_PBUF
+    rambuf = pbuf_alloc(PBUF_IP, fragsize, PBUF_RAM);
+    if (rambuf == NULL) {
+      goto memerr;
+    }
+    LWIP_ASSERT("this needs a pbuf in one piece!",
+                (rambuf->len == rambuf->tot_len) && (rambuf->next == NULL));
+    poff += pbuf_copy_partial(p, rambuf->payload, fragsize, poff);
+    /* make room for the IP header */
+    if (pbuf_add_header(rambuf, IP_HLEN)) {
+      pbuf_free(rambuf);
+      goto memerr;
+    }
+    /* fill in the IP header */
+    SMEMCPY(rambuf->payload, original_iphdr, IP_HLEN);
+    iphdr = (struct ip_hdr *)rambuf->payload;
+#else /* LWIP_NETIF_TX_SINGLE_PBUF */
+    /* When not using a static buffer, create a chain of pbufs.
+     * The first will be a PBUF_RAM holding the link and IP header.
+     * The rest will be PBUF_REFs mirroring the pbuf chain to be fragged,
+     * but limited to the size of an mtu.
+     */
+    rambuf = pbuf_alloc(PBUF_LINK, IP_HLEN, PBUF_RAM);
+    if (rambuf == NULL) {
+      goto memerr;
+    }
+    LWIP_ASSERT("this needs a pbuf in one piece!",
+                (rambuf->len >= (IP_HLEN)));
+    SMEMCPY(rambuf->payload, original_iphdr, IP_HLEN);
+    iphdr = (struct ip_hdr *)rambuf->payload;
+
+    left_to_copy = fragsize;
+    while (left_to_copy) {
+      struct pbuf_custom_ref *pcr;
+      u16_t plen = (u16_t)(p->len - poff);
+      LWIP_ASSERT("p->len >= poff", p->len >= poff);
+      newpbuflen = LWIP_MIN(left_to_copy, plen);
+      /* Is this pbuf already empty? */
+      if (!newpbuflen) {
+        poff = 0;
+        p = p->next;
+        continue;
+      }
+      pcr = ip_frag_alloc_pbuf_custom_ref();
+      if (pcr == NULL) {
+        pbuf_free(rambuf);
+        goto memerr;
+      }
+      /* Mirror this pbuf, although we might not need all of it. */
+      newpbuf = pbuf_alloced_custom(PBUF_RAW, newpbuflen, PBUF_REF, &pcr->pc,
+                                    (u8_t *)p->payload + poff, newpbuflen);
+      if (newpbuf == NULL) {
+        ip_frag_free_pbuf_custom_ref(pcr);
+        pbuf_free(rambuf);
+        goto memerr;
+      }
+      pbuf_ref(p);
+      pcr->original = p;
+      pcr->pc.custom_free_function = ipfrag_free_pbuf_custom;
+
+      /* Add it to end of rambuf's chain, but using pbuf_cat, not pbuf_chain
+       * so that it is removed when pbuf_dechain is later called on rambuf.
+       */
+      pbuf_cat(rambuf, newpbuf);
+      left_to_copy = (u16_t)(left_to_copy - newpbuflen);
+      if (left_to_copy) {
+        poff = 0;
+        p = p->next;
+      }
+    }
+    poff = (u16_t)(poff + newpbuflen);
+#endif /* LWIP_NETIF_TX_SINGLE_PBUF */
+
+    /* Correct header */
+    last = (left <= netif->mtu - IP_HLEN);
+
+    /* Set new offset and MF flag */
+    tmp = (IP_OFFMASK & (ofo));
+    if (!last || mf_set) {
+      /* the last fragment has MF set if the input frame had it */
+      tmp = tmp | IP_MF;
+    }
+    IPH_OFFSET_SET(iphdr, lwip_htons(tmp));
+    IPH_LEN_SET(iphdr, lwip_htons((u16_t)(fragsize + IP_HLEN)));
+    IPH_CHKSUM_SET(iphdr, 0);
+#if CHECKSUM_GEN_IP
+    IF__NETIF_CHECKSUM_ENABLED(netif, NETIF_CHECKSUM_GEN_IP) {
+      IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, IP_HLEN));
+    }
+#endif /* CHECKSUM_GEN_IP */
+
+    /* No need for separate header pbuf - we allowed room for it in rambuf
+     * when allocated.
+     */
+    netif->output(netif, rambuf, dest);
+    IPFRAG_STATS_INC(ip_frag.xmit);
+
+    /* Unfortunately we can't reuse rambuf - the hardware may still be
+     * using the buffer. Instead we free it (and the ensuing chain) and
+     * recreate it next time round the loop. If we're lucky the hardware
+     * will have already sent the packet, the free will really free, and
+     * there will be zero memory penalty.
+     */
+
+    pbuf_free(rambuf);
+    left = (u16_t)(left - fragsize);
+    ofo = (u16_t)(ofo + nfb);
+  }
+  MIB2_STATS_INC(mib2.ipfragoks);
+  return ERR_OK;
+memerr:
+  MIB2_STATS_INC(mib2.ipfragfails);
+  return ERR_MEM;
+}
+#endif /* IP_FRAG */
+
+#endif /* LWIP_IPV4 */

Drivers/LwIP/src/core/ipv6/dhcp6.c

@@ -0,0 +1,821 @@
+/**
+ * @file
+ *
+ * @defgroup dhcp6 DHCPv6
+ * @ingroup ip6
+ * DHCPv6 client: IPv6 address autoconfiguration as per
+ * RFC 3315 (stateful DHCPv6) and
+ * RFC 3736 (stateless DHCPv6).
+ *
+ * For now, only stateless DHCPv6 is implemented!
+ *
+ * TODO:
+ * - enable/disable API to not always start when RA is received
+ * - stateful DHCPv6 (for now, only stateless DHCPv6 for DNS and NTP servers works)
+ * - create Client Identifier?
+ * - only start requests if a valid local address is available on the netif
+ * - only start information requests if required (not for every RA)
+ *
+ * dhcp6_enable_stateful() enables stateful DHCPv6 for a netif (stateless disabled)<br>
+ * dhcp6_enable_stateless() enables stateless DHCPv6 for a netif (stateful disabled)<br>
+ * dhcp6_disable() disable DHCPv6 for a netif
+ *
+ * When enabled, requests are only issued after receipt of RA with the
+ * corresponding bits set.
+ */
+
+/*
+ * Copyright (c) 2018 Simon Goldschmidt
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Simon Goldschmidt <goldsimon@gmx.de>
+ */
+
+#include "lwip/opt.h"
+
+#if LWIP_IPV6 && LWIP_IPV6_DHCP6 /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/dhcp6.h"
+#include "lwip/prot/dhcp6.h"
+#include "lwip/def.h"
+#include "lwip/udp.h"
+#include "lwip/dns.h"
+
+#include <string.h>
+
+#ifdef LWIP_HOOK_FILENAME
+#include LWIP_HOOK_FILENAME
+#endif
+#ifndef LWIP_HOOK_DHCP6_APPEND_OPTIONS
+#define LWIP_HOOK_DHCP6_APPEND_OPTIONS(netif, dhcp6, state, msg, msg_type, options_len_ptr, max_len)
+#endif
+#ifndef LWIP_HOOK_DHCP6_PARSE_OPTION
+#define LWIP_HOOK_DHCP6_PARSE_OPTION(netif, dhcp6, state, msg, msg_type, option, len, pbuf, offset) do { LWIP_UNUSED_ARG(msg); } while(0)
+#endif
+
+#if LWIP_DNS && LWIP_DHCP6_MAX_DNS_SERVERS
+#if DNS_MAX_SERVERS > LWIP_DHCP6_MAX_DNS_SERVERS
+#define LWIP_DHCP6_PROVIDE_DNS_SERVERS LWIP_DHCP6_MAX_DNS_SERVERS
+#else
+#define LWIP_DHCP6_PROVIDE_DNS_SERVERS DNS_MAX_SERVERS
+#endif
+#else
+#define LWIP_DHCP6_PROVIDE_DNS_SERVERS 0
+#endif
+
+
+/** Option handling: options are parsed in dhcp6_parse_reply
+ * and saved in an array where other functions can load them from.
+ * This might be moved into the struct dhcp6 (not necessarily since
+ * lwIP is single-threaded and the array is only used while in recv
+ * callback). */
+enum dhcp6_option_idx {
+  DHCP6_OPTION_IDX_CLI_ID = 0,
+  DHCP6_OPTION_IDX_SERVER_ID,
+#if LWIP_DHCP6_PROVIDE_DNS_SERVERS
+  DHCP6_OPTION_IDX_DNS_SERVER,
+  DHCP6_OPTION_IDX_DOMAIN_LIST,
+#endif /* LWIP_DHCP_PROVIDE_DNS_SERVERS */
+#if LWIP_DHCP6_GET_NTP_SRV
+  DHCP6_OPTION_IDX_NTP_SERVER,
+#endif /* LWIP_DHCP_GET_NTP_SRV */
+  DHCP6_OPTION_IDX_MAX
+};
+
+struct dhcp6_option_info {
+  u8_t option_given;
+  u16_t val_start;
+  u16_t val_length;
+};
+
+/** Holds the decoded option info, only valid while in dhcp6_recv. */
+struct dhcp6_option_info dhcp6_rx_options[DHCP6_OPTION_IDX_MAX];
+
+#define dhcp6_option_given(dhcp6, idx)           (dhcp6_rx_options[idx].option_given != 0)
+#define dhcp6_got_option(dhcp6, idx)             (dhcp6_rx_options[idx].option_given = 1)
+#define dhcp6_clear_option(dhcp6, idx)           (dhcp6_rx_options[idx].option_given = 0)
+#define dhcp6_clear_all_options(dhcp6)           (memset(dhcp6_rx_options, 0, sizeof(dhcp6_rx_options)))
+#define dhcp6_get_option_start(dhcp6, idx)       (dhcp6_rx_options[idx].val_start)
+#define dhcp6_get_option_length(dhcp6, idx)      (dhcp6_rx_options[idx].val_length)
+#define dhcp6_set_option(dhcp6, idx, start, len) do { dhcp6_rx_options[idx].val_start = (start); dhcp6_rx_options[idx].val_length = (len); }while(0)
+
+
+const ip_addr_t dhcp6_All_DHCP6_Relay_Agents_and_Servers = IPADDR6_INIT_HOST(0xFF020000, 0, 0, 0x00010002);
+const ip_addr_t dhcp6_All_DHCP6_Servers = IPADDR6_INIT_HOST(0xFF020000, 0, 0, 0x00010003);
+
+static struct udp_pcb *dhcp6_pcb;
+static u8_t dhcp6_pcb_refcount;
+
+
+/* receive, unfold, parse and free incoming messages */
+static void dhcp6_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, const ip_addr_t *addr, u16_t port);
+
+/** Ensure DHCP PCB is allocated and bound */
+static err_t
+dhcp6_inc_pcb_refcount(void)
+{
+  if (dhcp6_pcb_refcount == 0) {
+    LWIP_ASSERT("dhcp6_inc_pcb_refcount(): memory leak", dhcp6_pcb == NULL);
+
+    /* allocate UDP PCB */
+    dhcp6_pcb = udp_new_ip6();
+
+    if (dhcp6_pcb == NULL) {
+      return ERR_MEM;
+    }
+
+    ip_set_option(dhcp6_pcb, SOF_BROADCAST);
+
+    /* set up local and remote port for the pcb -> listen on all interfaces on all src/dest IPs */
+    udp_bind(dhcp6_pcb, IP6_ADDR_ANY, DHCP6_CLIENT_PORT);
+    udp_recv(dhcp6_pcb, dhcp6_recv, NULL);
+  }
+
+  dhcp6_pcb_refcount++;
+
+  return ERR_OK;
+}
+
+/** Free DHCP PCB if the last netif stops using it */
+static void
+dhcp6_dec_pcb_refcount(void)
+{
+  LWIP_ASSERT("dhcp6_pcb_refcount(): refcount error", (dhcp6_pcb_refcount > 0));
+  dhcp6_pcb_refcount--;
+
+  if (dhcp6_pcb_refcount == 0) {
+    udp_remove(dhcp6_pcb);
+    dhcp6_pcb = NULL;
+  }
+}
+
+/**
+ * @ingroup dhcp6
+ * Set a statically allocated struct dhcp6 to work with.
+ * Using this prevents dhcp6_start to allocate it using mem_malloc.
+ *
+ * @param netif the netif for which to set the struct dhcp
+ * @param dhcp6 (uninitialised) dhcp6 struct allocated by the application
+ */
+void
+dhcp6_set_struct(struct netif *netif, struct dhcp6 *dhcp6)
+{
+  LWIP_ASSERT("netif != NULL", netif != NULL);
+  LWIP_ASSERT("dhcp6 != NULL", dhcp6 != NULL);
+  LWIP_ASSERT("netif already has a struct dhcp6 set", netif_dhcp6_data(netif) == NULL);
+
+  /* clear data structure */
+  memset(dhcp6, 0, sizeof(struct dhcp6));
+  /* dhcp6_set_state(&dhcp, DHCP6_STATE_OFF); */
+  netif_set_client_data(netif, LWIP_NETIF_CLIENT_DATA_INDEX_DHCP6, dhcp6);
+}
+
+/**
+ * @ingroup dhcp6
+ * Removes a struct dhcp6 from a netif.
+ *
+ * ATTENTION: Only use this when not using dhcp6_set_struct() to allocate the
+ *            struct dhcp6 since the memory is passed back to the heap.
+ *
+ * @param netif the netif from which to remove the struct dhcp
+ */
+void dhcp6_cleanup(struct netif *netif)
+{
+  LWIP_ASSERT("netif != NULL", netif != NULL);
+
+  if (netif_dhcp6_data(netif) != NULL) {
+    mem_free(netif_dhcp6_data(netif));
+    netif_set_client_data(netif, LWIP_NETIF_CLIENT_DATA_INDEX_DHCP6, NULL);
+  }
+}
+
+static struct dhcp6*
+dhcp6_get_struct(struct netif *netif, const char *dbg_requester)
+{
+  struct dhcp6 *dhcp6 = netif_dhcp6_data(netif);
+  if (dhcp6 == NULL) {
+    LWIP_DEBUGF(DHCP6_DEBUG | LWIP_DBG_TRACE, ("%s: mallocing new DHCPv6 client\n", dbg_requester));
+    dhcp6 = (struct dhcp6 *)mem_malloc(sizeof(struct dhcp6));
+    if (dhcp6 == NULL) {
+      LWIP_DEBUGF(DHCP6_DEBUG | LWIP_DBG_TRACE, ("%s: could not allocate dhcp6\n", dbg_requester));
+      return NULL;
+    }
+
+    /* clear data structure, this implies DHCP6_STATE_OFF */
+    memset(dhcp6, 0, sizeof(struct dhcp6));
+    /* store this dhcp6 client in the netif */
+    netif_set_client_data(netif, LWIP_NETIF_CLIENT_DATA_INDEX_DHCP6, dhcp6);
+  } else {
+    /* already has DHCP6 client attached */
+    LWIP_DEBUGF(DHCP6_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("%s: using existing DHCPv6 client\n", dbg_requester));
+  }
+
+  if (!dhcp6->pcb_allocated) {
+    if (dhcp6_inc_pcb_refcount() != ERR_OK) { /* ensure DHCP6 PCB is allocated */
+      mem_free(dhcp6);
+      netif_set_client_data(netif, LWIP_NETIF_CLIENT_DATA_INDEX_DHCP6, NULL);
+      return NULL;
+    }
+    LWIP_DEBUGF(DHCP6_DEBUG | LWIP_DBG_TRACE, ("%s: allocated dhcp6\n", dbg_requester));
+    dhcp6->pcb_allocated = 1;
+  }
+  return dhcp6;
+}
+
+/*
+ * Set the DHCPv6 state
+ * If the state changed, reset the number of tries.
+ */
+static void
+dhcp6_set_state(struct dhcp6 *dhcp6, u8_t new_state, const char *dbg_caller)
+{
+  LWIP_DEBUGF(DHCP6_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("DHCPv6 state: %d -> %d (%s)\n",
+    dhcp6->state, new_state, dbg_caller));
+  if (new_state != dhcp6->state) {
+    dhcp6->state = new_state;
+    dhcp6->tries = 0;
+    dhcp6->request_timeout = 0;
+  }
+}
+
+static int
+dhcp6_stateless_enabled(struct dhcp6 *dhcp6)
+{
+  if ((dhcp6->state == DHCP6_STATE_STATELESS_IDLE) ||
+      (dhcp6->state == DHCP6_STATE_REQUESTING_CONFIG)) {
+    return 1;
+  }
+  return 0;
+}
+
+/*static int
+dhcp6_stateful_enabled(struct dhcp6 *dhcp6)
+{
+  if (dhcp6->state == DHCP6_STATE_OFF) {
+    return 0;
+  }
+  if (dhcp6_stateless_enabled(dhcp6)) {
+    return 0;
+  }
+  return 1;
+}*/
+
+/**
+ * @ingroup dhcp6
+ * Enable stateful DHCPv6 on this netif
+ * Requests are sent on receipt of an RA message with the
+ * ND6_RA_FLAG_MANAGED_ADDR_CONFIG flag set.
+ *
+ * A struct dhcp6 will be allocated for this netif if not
+ * set via @ref dhcp6_set_struct before.
+ *
+ * @todo: stateful DHCPv6 not supported, yet
+ */
+err_t
+dhcp6_enable_stateful(struct netif *netif)
+{
+  LWIP_UNUSED_ARG(netif);
+  LWIP_DEBUGF(DHCP6_DEBUG | LWIP_DBG_TRACE, ("stateful dhcp6 not implemented yet\n"));
+  return ERR_VAL;
+}
+
+/**
+ * @ingroup dhcp6
+ * Enable stateless DHCPv6 on this netif
+ * Requests are sent on receipt of an RA message with the
+ * ND6_RA_FLAG_OTHER_CONFIG flag set.
+ *
+ * A struct dhcp6 will be allocated for this netif if not
+ * set via @ref dhcp6_set_struct before.
+ */
+err_t
+dhcp6_enable_stateless(struct netif *netif)
+{
+  struct dhcp6 *dhcp6;
+
+  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp6_enable_stateless(netif=%p) %c%c%"U16_F"\n", (void *)netif, netif->name[0], netif->name[1], (u16_t)netif->num));
+
+  dhcp6 = dhcp6_get_struct(netif, "dhcp6_enable_stateless()");
+  if (dhcp6 == NULL) {
+    return ERR_MEM;
+  }
+  if (dhcp6_stateless_enabled(dhcp6)) {
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp6_enable_stateless(): stateless DHCPv6 already enabled\n"));
+    return ERR_OK;
+  } else if (dhcp6->state != DHCP6_STATE_OFF) {
+    /* stateful running */
+    /* @todo: stop stateful once it is implemented */
+    LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp6_enable_stateless(): switching from stateful to stateless DHCPv6\n"));
+  }
+  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp6_enable_stateless(): stateless DHCPv6 enabled\n"));
+  dhcp6_set_state(dhcp6, DHCP6_STATE_STATELESS_IDLE, "dhcp6_enable_stateless");
+  return ERR_OK;
+}
+
+/**
+ * @ingroup dhcp6
+ * Disable stateful or stateless DHCPv6 on this netif
+ * Requests are sent on receipt of an RA message with the
+ * ND6_RA_FLAG_OTHER_CONFIG flag set.
+ */
+void
+dhcp6_disable(struct netif *netif)
+{
+  struct dhcp6 *dhcp6;
+
+  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp6_disable(netif=%p) %c%c%"U16_F"\n", (void *)netif, netif->name[0], netif->name[1], (u16_t)netif->num));
+
+  dhcp6 = netif_dhcp6_data(netif);
+  if (dhcp6 != NULL) {
+    if (dhcp6->state != DHCP6_STATE_OFF) {
+      LWIP_DEBUGF(DHCP6_DEBUG | LWIP_DBG_TRACE, ("dhcp6_disable(): DHCPv6 disabled (old state: %s)\n",
+        (dhcp6_stateless_enabled(dhcp6) ? "stateless" : "stateful")));
+      dhcp6_set_state(dhcp6, DHCP6_STATE_OFF, "dhcp6_disable");
+      if (dhcp6->pcb_allocated != 0) {
+        dhcp6_dec_pcb_refcount(); /* free DHCPv6 PCB if not needed any more */
+        dhcp6->pcb_allocated = 0;
+      }
+    }
+  }
+}
+
+/**
+ * Create a DHCPv6 request, fill in common headers
+ *
+ * @param netif the netif under DHCPv6 control
+ * @param dhcp6 dhcp6 control struct
+ * @param message_type message type of the request
+ * @param opt_len_alloc option length to allocate
+ * @param options_out_len option length on exit
+ * @return a pbuf for the message
+ */
+static struct pbuf *
+dhcp6_create_msg(struct netif *netif, struct dhcp6 *dhcp6, u8_t message_type,
+                 u16_t opt_len_alloc, u16_t *options_out_len)
+{
+  struct pbuf *p_out;
+  struct dhcp6_msg *msg_out;
+
+  LWIP_ERROR("dhcp6_create_msg: netif != NULL", (netif != NULL), return NULL;);
+  LWIP_ERROR("dhcp6_create_msg: dhcp6 != NULL", (dhcp6 != NULL), return NULL;);
+  p_out = pbuf_alloc(PBUF_TRANSPORT, sizeof(struct dhcp6_msg) + opt_len_alloc, PBUF_RAM);
+  if (p_out == NULL) {
+    LWIP_DEBUGF(DHCP6_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS,
+                ("dhcp6_create_msg(): could not allocate pbuf\n"));
+    return NULL;
+  }
+  LWIP_ASSERT("dhcp6_create_msg: check that first pbuf can hold struct dhcp6_msg",
+              (p_out->len >= sizeof(struct dhcp6_msg) + opt_len_alloc));
+
+  /* @todo: limit new xid for certain message types? */
+  /* reuse transaction identifier in retransmissions */
+  if (dhcp6->tries == 0) {
+    dhcp6->xid = LWIP_RAND() & 0xFFFFFF;
+  }
+
+  LWIP_DEBUGF(DHCP6_DEBUG | LWIP_DBG_TRACE,
+              ("transaction id xid(%"X32_F")\n", dhcp6->xid));
+
+  msg_out = (struct dhcp6_msg *)p_out->payload;
+  memset(msg_out, 0, sizeof(struct dhcp6_msg) + opt_len_alloc);
+
+  msg_out->msgtype = message_type;
+  msg_out->transaction_id[0] = (u8_t)(dhcp6->xid >> 16);
+  msg_out->transaction_id[1] = (u8_t)(dhcp6->xid >> 8);
+  msg_out->transaction_id[2] = (u8_t)dhcp6->xid;
+  *options_out_len = 0;
+  return p_out;
+}
+
+static u16_t
+dhcp6_option_short(u16_t options_out_len, u8_t *options, u16_t value)
+{
+  options[options_out_len++] = (u8_t)((value & 0xff00U) >> 8);
+  options[options_out_len++] = (u8_t) (value & 0x00ffU);
+  return options_out_len;
+}
+
+static u16_t
+dhcp6_option_optionrequest(u16_t options_out_len, u8_t *options, const u16_t *req_options,
+                           u16_t num_req_options, u16_t max_len)
+{
+  size_t i;
+  u16_t ret;
+
+  LWIP_ASSERT("dhcp6_option_optionrequest: options_out_len + sizeof(struct dhcp6_msg) + addlen <= max_len",
+    sizeof(struct dhcp6_msg) + options_out_len + 4U + (2U * num_req_options) <= max_len);
+  LWIP_UNUSED_ARG(max_len);
+
+  ret = dhcp6_option_short(options_out_len, options, DHCP6_OPTION_ORO);
+  ret = dhcp6_option_short(ret, options, 2 * num_req_options);
+  for (i = 0; i < num_req_options; i++) {
+    ret = dhcp6_option_short(ret, options, req_options[i]);
+  }
+  return ret;
+}
+
+/* All options are added, shrink the pbuf to the required size */
+static void
+dhcp6_msg_finalize(u16_t options_out_len, struct pbuf *p_out)
+{
+  /* shrink the pbuf to the actual content length */
+  pbuf_realloc(p_out, (u16_t)(sizeof(struct dhcp6_msg) + options_out_len));
+}
+
+
+#if LWIP_IPV6_DHCP6_STATELESS
+static void
+dhcp6_information_request(struct netif *netif, struct dhcp6 *dhcp6)
+{
+  const u16_t requested_options[] = {
+#if LWIP_DHCP6_PROVIDE_DNS_SERVERS
+    DHCP6_OPTION_DNS_SERVERS,
+    DHCP6_OPTION_DOMAIN_LIST
+#endif
+#if LWIP_DHCP6_GET_NTP_SRV
+    , DHCP6_OPTION_SNTP_SERVERS
+#endif
+  };
+
+  u16_t msecs;
+  struct pbuf *p_out;
+  u16_t options_out_len;
+  LWIP_DEBUGF(DHCP6_DEBUG | LWIP_DBG_TRACE, ("dhcp6_information_request()\n"));
+  /* create and initialize the DHCP message header */
+  p_out = dhcp6_create_msg(netif, dhcp6, DHCP6_INFOREQUEST, 4 + sizeof(requested_options), &options_out_len);
+  if (p_out != NULL) {
+    err_t err;
+    struct dhcp6_msg *msg_out = (struct dhcp6_msg *)p_out->payload;
+    u8_t *options = (u8_t *)(msg_out + 1);
+    LWIP_DEBUGF(DHCP6_DEBUG | LWIP_DBG_TRACE, ("dhcp6_information_request: making request\n"));
+
+    options_out_len = dhcp6_option_optionrequest(options_out_len, options, requested_options,
+      LWIP_ARRAYSIZE(requested_options), p_out->len);
+    LWIP_HOOK_DHCP6_APPEND_OPTIONS(netif, dhcp6, DHCP6_STATE_REQUESTING_CONFIG, msg_out,
+      DHCP6_INFOREQUEST, options_out_len, p_out->len);
+    dhcp6_msg_finalize(options_out_len, p_out);
+
+    err = udp_sendto_if(dhcp6_pcb, p_out, &dhcp6_All_DHCP6_Relay_Agents_and_Servers, DHCP6_SERVER_PORT, netif);
+    pbuf_free(p_out);
+    LWIP_DEBUGF(DHCP6_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp6_information_request: INFOREQUESTING -> %d\n", (int)err));
+    LWIP_UNUSED_ARG(err);
+  } else {
+    LWIP_DEBUGF(DHCP6_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("dhcp6_information_request: could not allocate DHCP6 request\n"));
+  }
+  dhcp6_set_state(dhcp6, DHCP6_STATE_REQUESTING_CONFIG, "dhcp6_information_request");
+  if (dhcp6->tries < 255) {
+    dhcp6->tries++;
+  }
+  msecs = (u16_t)((dhcp6->tries < 6 ? 1 << dhcp6->tries : 60) * 1000);
+  dhcp6->request_timeout = (u16_t)((msecs + DHCP6_TIMER_MSECS - 1) / DHCP6_TIMER_MSECS);
+  LWIP_DEBUGF(DHCP6_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp6_information_request(): set request timeout %"U16_F" msecs\n", msecs));
+}
+
+static err_t
+dhcp6_request_config(struct netif *netif, struct dhcp6 *dhcp6)
+{
+  /* stateless mode enabled and no request running? */
+  if (dhcp6->state == DHCP6_STATE_STATELESS_IDLE) {
+    /* send Information-request and wait for answer; setup receive timeout */
+    dhcp6_information_request(netif, dhcp6);
+  }
+
+  return ERR_OK;
+}
+
+static void
+dhcp6_abort_config_request(struct dhcp6 *dhcp6)
+{
+  if (dhcp6->state == DHCP6_STATE_REQUESTING_CONFIG) {
+    /* abort running request */
+    dhcp6_set_state(dhcp6, DHCP6_STATE_STATELESS_IDLE, "dhcp6_abort_config_request");
+  }
+}
+
+/* Handle a REPLY to INFOREQUEST
+ * This parses DNS and NTP server addresses from the reply.
+ */
+static void
+dhcp6_handle_config_reply(struct netif *netif, struct pbuf *p_msg_in)
+{
+  struct dhcp6 *dhcp6 = netif_dhcp6_data(netif);
+
+  LWIP_UNUSED_ARG(dhcp6);
+  LWIP_UNUSED_ARG(p_msg_in);
+
+#if LWIP_DHCP6_PROVIDE_DNS_SERVERS
+  if (dhcp6_option_given(dhcp6, DHCP6_OPTION_IDX_DNS_SERVER)) {
+    ip_addr_t dns_addr;
+    ip6_addr_t *dns_addr6;
+    u16_t op_start = dhcp6_get_option_start(dhcp6, DHCP6_OPTION_IDX_DNS_SERVER);
+    u16_t op_len = dhcp6_get_option_length(dhcp6, DHCP6_OPTION_IDX_DNS_SERVER);
+    u16_t idx;
+    u8_t n;
+
+    ip_addr_set_zero_ip6(&dns_addr);
+    dns_addr6 = ip_2_ip6(&dns_addr);
+    for (n = 0, idx = op_start; (idx < op_start + op_len) && (n < LWIP_DHCP6_PROVIDE_DNS_SERVERS);
+         n++, idx += sizeof(struct ip6_addr_packed)) {
+      u16_t copied = pbuf_copy_partial(p_msg_in, dns_addr6, sizeof(struct ip6_addr_packed), idx);
+      if (copied != sizeof(struct ip6_addr_packed)) {
+        /* pbuf length mismatch */
+        return;
+      }
+      ip6_addr_assign_zone(dns_addr6, IP6_UNKNOWN, netif);
+      /* @todo: do we need a different offset than DHCP(v4)? */
+      dns_setserver(n, &dns_addr);
+    }
+  }
+  /* @ todo: parse and set Domain Search List */
+#endif /* LWIP_DHCP6_PROVIDE_DNS_SERVERS */
+
+#if LWIP_DHCP6_GET_NTP_SRV
+  if (dhcp6_option_given(dhcp6, DHCP6_OPTION_IDX_NTP_SERVER)) {
+    ip_addr_t ntp_server_addrs[LWIP_DHCP6_MAX_NTP_SERVERS];
+    u16_t op_start = dhcp6_get_option_start(dhcp6, DHCP6_OPTION_IDX_NTP_SERVER);
+    u16_t op_len = dhcp6_get_option_length(dhcp6, DHCP6_OPTION_IDX_NTP_SERVER);
+    u16_t idx;
+    u8_t n;
+
+    for (n = 0, idx = op_start; (idx < op_start + op_len) && (n < LWIP_DHCP6_MAX_NTP_SERVERS);
+         n++, idx += sizeof(struct ip6_addr_packed)) {
+      u16_t copied;
+      ip6_addr_t *ntp_addr6 = ip_2_ip6(&ntp_server_addrs[n]);
+      ip_addr_set_zero_ip6(&ntp_server_addrs[n]);
+      copied = pbuf_copy_partial(p_msg_in, ntp_addr6, sizeof(struct ip6_addr_packed), idx);
+      if (copied != sizeof(struct ip6_addr_packed)) {
+        /* pbuf length mismatch */
+        return;
+      }
+      ip6_addr_assign_zone(ntp_addr6, IP6_UNKNOWN, netif);
+    }
+    dhcp6_set_ntp_servers(n, ntp_server_addrs);
+  }
+#endif /* LWIP_DHCP6_GET_NTP_SRV */
+}
+#endif /* LWIP_IPV6_DHCP6_STATELESS */
+
+/** This function is called from nd6 module when an RA message is received
+ * It triggers DHCPv6 requests (if enabled).
+ */
+void
+dhcp6_nd6_ra_trigger(struct netif *netif, u8_t managed_addr_config, u8_t other_config)
+{
+  struct dhcp6 *dhcp6;
+
+  LWIP_ASSERT("netif != NULL", netif != NULL);
+  dhcp6 = netif_dhcp6_data(netif);
+
+  LWIP_UNUSED_ARG(managed_addr_config);
+  LWIP_UNUSED_ARG(other_config);
+  LWIP_UNUSED_ARG(dhcp6);
+
+#if LWIP_IPV6_DHCP6_STATELESS
+  if (dhcp6 != NULL) {
+    if (dhcp6_stateless_enabled(dhcp6)) {
+      if (other_config) {
+        dhcp6_request_config(netif, dhcp6);
+      } else {
+        dhcp6_abort_config_request(dhcp6);
+      }
+    }
+  }
+#endif /* LWIP_IPV6_DHCP6_STATELESS */
+}
+
+/**
+ * Parse the DHCPv6 message and extract the DHCPv6 options.
+ *
+ * Extract the DHCPv6 options (offset + length) so that we can later easily
+ * check for them or extract the contents.
+ */
+static err_t
+dhcp6_parse_reply(struct pbuf *p, struct dhcp6 *dhcp6)
+{
+  u16_t offset;
+  u16_t offset_max;
+  u16_t options_idx;
+  struct dhcp6_msg *msg_in;
+
+  LWIP_UNUSED_ARG(dhcp6);
+
+  /* clear received options */
+  dhcp6_clear_all_options(dhcp6);
+  msg_in = (struct dhcp6_msg *)p->payload;
+
+  /* parse options */
+
+  options_idx = sizeof(struct dhcp6_msg);
+  /* parse options to the end of the received packet */
+  offset_max = p->tot_len;
+
+  offset = options_idx;
+  /* at least 4 byte to read? */
+  while ((offset + 4 <= offset_max)) {
+    u8_t op_len_buf[4];
+    u8_t *op_len;
+    u16_t op;
+    u16_t len;
+    u16_t val_offset = (u16_t)(offset + 4);
+    if (val_offset < offset) {
+      /* overflow */
+      return ERR_BUF;
+    }
+    /* copy option + length, might be split across pbufs */
+    op_len = (u8_t *)pbuf_get_contiguous(p, op_len_buf, 4, 4, offset);
+    if (op_len == NULL) {
+      /* failed to get option and length */
+      return ERR_VAL;
+    }
+    op = (op_len[0] << 8) | op_len[1];
+    len = (op_len[2] << 8) | op_len[3];
+    offset = val_offset + len;
+    if (offset < val_offset) {
+      /* overflow */
+      return ERR_BUF;
+    }
+
+    switch (op) {
+      case (DHCP6_OPTION_CLIENTID):
+        dhcp6_got_option(dhcp6, DHCP6_OPTION_IDX_CLI_ID);
+        dhcp6_set_option(dhcp6, DHCP6_OPTION_IDX_CLI_ID, val_offset, len);
+        break;
+      case (DHCP6_OPTION_SERVERID):
+        dhcp6_got_option(dhcp6, DHCP6_OPTION_IDX_SERVER_ID);
+        dhcp6_set_option(dhcp6, DHCP6_OPTION_IDX_SERVER_ID, val_offset, len);
+        break;
+#if LWIP_DHCP6_PROVIDE_DNS_SERVERS
+      case (DHCP6_OPTION_DNS_SERVERS):
+        dhcp6_got_option(dhcp6, DHCP6_OPTION_IDX_DNS_SERVER);
+        dhcp6_set_option(dhcp6, DHCP6_OPTION_IDX_DNS_SERVER, val_offset, len);
+        break;
+      case (DHCP6_OPTION_DOMAIN_LIST):
+        dhcp6_got_option(dhcp6, DHCP6_OPTION_IDX_DOMAIN_LIST);
+        dhcp6_set_option(dhcp6, DHCP6_OPTION_IDX_DOMAIN_LIST, val_offset, len);
+        break;
+#endif /* LWIP_DHCP6_PROVIDE_DNS_SERVERS */
+#if LWIP_DHCP6_GET_NTP_SRV
+      case (DHCP6_OPTION_SNTP_SERVERS):
+        dhcp6_got_option(dhcp6, DHCP6_OPTION_IDX_NTP_SERVER);
+        dhcp6_set_option(dhcp6, DHCP6_OPTION_IDX_NTP_SERVER, val_offset, len);
+        break;
+#endif /* LWIP_DHCP6_GET_NTP_SRV*/
+      default:
+        LWIP_DEBUGF(DHCP6_DEBUG, ("skipping option %"U16_F" in options\n", op));
+        LWIP_HOOK_DHCP6_PARSE_OPTION(ip_current_netif(), dhcp6, dhcp6->state, msg_in,
+          msg_in->msgtype, op, len, q, val_offset);
+        break;
+    }
+  }
+  return ERR_OK;
+}
+
+static void
+dhcp6_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, const ip_addr_t *addr, u16_t port)
+{
+  struct netif *netif = ip_current_input_netif();
+  struct dhcp6 *dhcp6 = netif_dhcp6_data(netif);
+  struct dhcp6_msg *reply_msg = (struct dhcp6_msg *)p->payload;
+  u8_t msg_type;
+  u32_t xid;
+
+  LWIP_UNUSED_ARG(arg);
+
+  /* Caught DHCPv6 message from netif that does not have DHCPv6 enabled? -> not interested */
+  if ((dhcp6 == NULL) || (dhcp6->pcb_allocated == 0)) {
+    goto free_pbuf_and_return;
+  }
+
+  LWIP_ERROR("invalid server address type", IP_IS_V6(addr), goto free_pbuf_and_return;);
+
+  LWIP_DEBUGF(DHCP6_DEBUG | LWIP_DBG_TRACE, ("dhcp6_recv(pbuf = %p) from DHCPv6 server %s port %"U16_F"\n", (void *)p,
+    ipaddr_ntoa(addr), port));
+  LWIP_DEBUGF(DHCP6_DEBUG | LWIP_DBG_TRACE, ("pbuf->len = %"U16_F"\n", p->len));
+  LWIP_DEBUGF(DHCP6_DEBUG | LWIP_DBG_TRACE, ("pbuf->tot_len = %"U16_F"\n", p->tot_len));
+  /* prevent warnings about unused arguments */
+  LWIP_UNUSED_ARG(pcb);
+  LWIP_UNUSED_ARG(addr);
+  LWIP_UNUSED_ARG(port);
+
+  if (p->len < sizeof(struct dhcp6_msg)) {
+    LWIP_DEBUGF(DHCP6_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING, ("DHCPv6 reply message or pbuf too short\n"));
+    goto free_pbuf_and_return;
+  }
+
+  /* match transaction ID against what we expected */
+  xid = reply_msg->transaction_id[0] << 16;
+  xid |= reply_msg->transaction_id[1] << 8;
+  xid |= reply_msg->transaction_id[2];
+  if (xid != dhcp6->xid) {
+    LWIP_DEBUGF(DHCP6_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING,
+                ("transaction id mismatch reply_msg->xid(%"X32_F")!= dhcp6->xid(%"X32_F")\n", xid, dhcp6->xid));
+    goto free_pbuf_and_return;
+  }
+  /* option fields could be unfold? */
+  if (dhcp6_parse_reply(p, dhcp6) != ERR_OK) {
+    LWIP_DEBUGF(DHCP6_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS,
+                ("problem unfolding DHCPv6 message - too short on memory?\n"));
+    goto free_pbuf_and_return;
+  }
+
+  /* read DHCP message type */
+  msg_type = reply_msg->msgtype;
+  /* message type is DHCP6 REPLY? */
+  if (msg_type == DHCP6_REPLY) {
+    LWIP_DEBUGF(DHCP6_DEBUG | LWIP_DBG_TRACE, ("DHCP6_REPLY received\n"));
+#if LWIP_IPV6_DHCP6_STATELESS
+    /* in info-requesting state? */
+    if (dhcp6->state == DHCP6_STATE_REQUESTING_CONFIG) {
+      dhcp6_set_state(dhcp6, DHCP6_STATE_STATELESS_IDLE, "dhcp6_recv");
+      dhcp6_handle_config_reply(netif, p);
+    } else
+#endif /* LWIP_IPV6_DHCP6_STATELESS */
+    {
+      /* @todo: handle reply in other states? */
+    }
+  } else {
+    /* @todo: handle other message types */
+  }
+
+free_pbuf_and_return:
+  pbuf_free(p);
+}
+
+/**
+ * A DHCPv6 request has timed out.
+ *
+ * The timer that was started with the DHCPv6 request has
+ * timed out, indicating no response was received in time.
+ */
+static void
+dhcp6_timeout(struct netif *netif, struct dhcp6 *dhcp6)
+{
+  LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp6_timeout()\n"));
+
+  LWIP_UNUSED_ARG(netif);
+  LWIP_UNUSED_ARG(dhcp6);
+
+#if LWIP_IPV6_DHCP6_STATELESS
+  /* back-off period has passed, or server selection timed out */
+  if (dhcp6->state == DHCP6_STATE_REQUESTING_CONFIG) {
+    LWIP_DEBUGF(DHCP6_DEBUG | LWIP_DBG_TRACE, ("dhcp6_timeout(): retrying information request\n"));
+    dhcp6_information_request(netif, dhcp6);
+  }
+#endif /* LWIP_IPV6_DHCP6_STATELESS */
+}
+
+/**
+ * DHCPv6 timeout handling (this function must be called every 500ms,
+ * see @ref DHCP6_TIMER_MSECS).
+ *
+ * A DHCPv6 server is expected to respond within a short period of time.
+ * This timer checks whether an outstanding DHCPv6 request is timed out.
+ */
+void
+dhcp6_tmr(void)
+{
+  struct netif *netif;
+  /* loop through netif's */
+  NETIF_FOREACH(netif) {
+    struct dhcp6 *dhcp6 = netif_dhcp6_data(netif);
+    /* only act on DHCPv6 configured interfaces */
+    if (dhcp6 != NULL) {
+      /* timer is active (non zero), and is about to trigger now */
+      if (dhcp6->request_timeout > 1) {
+        dhcp6->request_timeout--;
+      } else if (dhcp6->request_timeout == 1) {
+        dhcp6->request_timeout--;
+        /* { dhcp6->request_timeout == 0 } */
+        LWIP_DEBUGF(DHCP6_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp6_tmr(): request timeout\n"));
+        /* this client's request timeout triggered */
+        dhcp6_timeout(netif, dhcp6);
+      }
+    }
+  }
+}
+
+#endif /* LWIP_IPV6 && LWIP_IPV6_DHCP6 */

Drivers/LwIP/src/core/ipv6/ethip6.c

@@ -0,0 +1,123 @@
+/**
+ * @file
+ *
+ * Ethernet output for IPv6. Uses ND tables for link-layer addressing.
+ */
+
+/*
+ * Copyright (c) 2010 Inico Technologies Ltd.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Ivan Delamer <delamer@inicotech.com>
+ *
+ *
+ * Please coordinate changes and requests with Ivan Delamer
+ * <delamer@inicotech.com>
+ */
+
+#include "lwip/opt.h"
+
+#if LWIP_IPV6 && LWIP_ETHERNET
+
+#include "lwip/ethip6.h"
+#include "lwip/nd6.h"
+#include "lwip/pbuf.h"
+#include "lwip/ip6.h"
+#include "lwip/ip6_addr.h"
+#include "lwip/inet_chksum.h"
+#include "lwip/netif.h"
+#include "lwip/icmp6.h"
+#include "lwip/prot/ethernet.h"
+#include "netif/ethernet.h"
+
+#include <string.h>
+
+/**
+ * Resolve and fill-in Ethernet address header for outgoing IPv6 packet.
+ *
+ * For IPv6 multicast, corresponding Ethernet addresses
+ * are selected and the packet is transmitted on the link.
+ *
+ * For unicast addresses, ask the ND6 module what to do. It will either let us
+ * send the the packet right away, or queue the packet for later itself, unless
+ * an error occurs.
+ *
+ * @todo anycast addresses
+ *
+ * @param netif The lwIP network interface which the IP packet will be sent on.
+ * @param q The pbuf(s) containing the IP packet to be sent.
+ * @param ip6addr The IP address of the packet destination.
+ *
+ * @return
+ * - ERR_OK or the return value of @ref nd6_get_next_hop_addr_or_queue.
+ */
+err_t
+ethip6_output(struct netif *netif, struct pbuf *q, const ip6_addr_t *ip6addr)
+{
+  struct eth_addr dest;
+  const u8_t *hwaddr;
+  err_t result;
+
+  LWIP_ASSERT_CORE_LOCKED();
+
+  /* The destination IP address must be properly zoned from here on down. */
+  IP6_ADDR_ZONECHECK_NETIF(ip6addr, netif);
+
+  /* multicast destination IP address? */
+  if (ip6_addr_ismulticast(ip6addr)) {
+    /* Hash IP multicast address to MAC address.*/
+    dest.addr[0] = 0x33;
+    dest.addr[1] = 0x33;
+    dest.addr[2] = ((const u8_t *)(&(ip6addr->addr[3])))[0];
+    dest.addr[3] = ((const u8_t *)(&(ip6addr->addr[3])))[1];
+    dest.addr[4] = ((const u8_t *)(&(ip6addr->addr[3])))[2];
+    dest.addr[5] = ((const u8_t *)(&(ip6addr->addr[3])))[3];
+
+    /* Send out. */
+    return ethernet_output(netif, q, (const struct eth_addr*)(netif->hwaddr), &dest, ETHTYPE_IPV6);
+  }
+
+  /* We have a unicast destination IP address */
+  /* @todo anycast? */
+
+  /* Ask ND6 what to do with the packet. */
+  result = nd6_get_next_hop_addr_or_queue(netif, q, ip6addr, &hwaddr);
+  if (result != ERR_OK) {
+    return result;
+  }
+
+  /* If no hardware address is returned, nd6 has queued the packet for later. */
+  if (hwaddr == NULL) {
+    return ERR_OK;
+  }
+
+  /* Send out the packet using the returned hardware address. */
+  SMEMCPY(dest.addr, hwaddr, 6);
+  return ethernet_output(netif, q, (const struct eth_addr*)(netif->hwaddr), &dest, ETHTYPE_IPV6);
+}
+
+#endif /* LWIP_IPV6 && LWIP_ETHERNET */

Drivers/LwIP/src/core/ipv6/icmp6.c

@@ -0,0 +1,425 @@
+/**
+ * @file
+ *
+ * IPv6 version of ICMP, as per RFC 4443.
+ */
+
+/*
+ * Copyright (c) 2010 Inico Technologies Ltd.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Ivan Delamer <delamer@inicotech.com>
+ *
+ *
+ * Please coordinate changes and requests with Ivan Delamer
+ * <delamer@inicotech.com>
+ */
+
+#include "lwip/opt.h"
+
+#if LWIP_ICMP6 && LWIP_IPV6 /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/icmp6.h"
+#include "lwip/prot/icmp6.h"
+#include "lwip/ip6.h"
+#include "lwip/ip6_addr.h"
+#include "lwip/inet_chksum.h"
+#include "lwip/pbuf.h"
+#include "lwip/netif.h"
+#include "lwip/nd6.h"
+#include "lwip/mld6.h"
+#include "lwip/ip.h"
+#include "lwip/stats.h"
+
+#include <string.h>
+
+#if !LWIP_ICMP6_DATASIZE || (LWIP_ICMP6_DATASIZE > (IP6_MIN_MTU_LENGTH - IP6_HLEN - ICMP6_HLEN))
+#undef LWIP_ICMP6_DATASIZE
+#define LWIP_ICMP6_DATASIZE   (IP6_MIN_MTU_LENGTH - IP6_HLEN - ICMP6_HLEN)
+#endif
+
+/* Forward declarations */
+static void icmp6_send_response(struct pbuf *p, u8_t code, u32_t data, u8_t type);
+static void icmp6_send_response_with_addrs(struct pbuf *p, u8_t code, u32_t data,
+    u8_t type, const ip6_addr_t *src_addr, const ip6_addr_t *dest_addr);
+static void icmp6_send_response_with_addrs_and_netif(struct pbuf *p, u8_t code, u32_t data,
+    u8_t type, const ip6_addr_t *src_addr, const ip6_addr_t *dest_addr, struct netif *netif);
+
+
+/**
+ * Process an input ICMPv6 message. Called by ip6_input.
+ *
+ * Will generate a reply for echo requests. Other messages are forwarded
+ * to nd6_input, or mld6_input.
+ *
+ * @param p the mld packet, p->payload pointing to the icmpv6 header
+ * @param inp the netif on which this packet was received
+ */
+void
+icmp6_input(struct pbuf *p, struct netif *inp)
+{
+  struct icmp6_hdr *icmp6hdr;
+  struct pbuf *r;
+  const ip6_addr_t *reply_src;
+
+  ICMP6_STATS_INC(icmp6.recv);
+
+  /* Check that ICMPv6 header fits in payload */
+  if (p->len < sizeof(struct icmp6_hdr)) {
+    /* drop short packets */
+    pbuf_free(p);
+    ICMP6_STATS_INC(icmp6.lenerr);
+    ICMP6_STATS_INC(icmp6.drop);
+    return;
+  }
+
+  icmp6hdr = (struct icmp6_hdr *)p->payload;
+
+#if CHECKSUM_CHECK_ICMP6
+  IF__NETIF_CHECKSUM_ENABLED(inp, NETIF_CHECKSUM_CHECK_ICMP6) {
+    if (ip6_chksum_pseudo(p, IP6_NEXTH_ICMP6, p->tot_len, ip6_current_src_addr(),
+                          ip6_current_dest_addr()) != 0) {
+      /* Checksum failed */
+      pbuf_free(p);
+      ICMP6_STATS_INC(icmp6.chkerr);
+      ICMP6_STATS_INC(icmp6.drop);
+      return;
+    }
+  }
+#endif /* CHECKSUM_CHECK_ICMP6 */
+
+  switch (icmp6hdr->type) {
+  case ICMP6_TYPE_NA: /* Neighbor advertisement */
+  case ICMP6_TYPE_NS: /* Neighbor solicitation */
+  case ICMP6_TYPE_RA: /* Router advertisement */
+  case ICMP6_TYPE_RD: /* Redirect */
+  case ICMP6_TYPE_PTB: /* Packet too big */
+    nd6_input(p, inp);
+    return;
+  case ICMP6_TYPE_RS:
+#if LWIP_IPV6_FORWARD
+    /* @todo implement router functionality */
+#endif
+    break;
+#if LWIP_IPV6_MLD
+  case ICMP6_TYPE_MLQ:
+  case ICMP6_TYPE_MLR:
+  case ICMP6_TYPE_MLD:
+    mld6_input(p, inp);
+    return;
+#endif
+  case ICMP6_TYPE_EREQ:
+#if !LWIP_MULTICAST_PING
+    /* multicast destination address? */
+    if (ip6_addr_ismulticast(ip6_current_dest_addr())) {
+      /* drop */
+      pbuf_free(p);
+      ICMP6_STATS_INC(icmp6.drop);
+      return;
+    }
+#endif /* LWIP_MULTICAST_PING */
+
+    /* Allocate reply. */
+    r = pbuf_alloc(PBUF_IP, p->tot_len, PBUF_RAM);
+    if (r == NULL) {
+      /* drop */
+      pbuf_free(p);
+      ICMP6_STATS_INC(icmp6.memerr);
+      return;
+    }
+
+    /* Copy echo request. */
+    if (pbuf_copy(r, p) != ERR_OK) {
+      /* drop */
+      pbuf_free(p);
+      pbuf_free(r);
+      ICMP6_STATS_INC(icmp6.err);
+      return;
+    }
+
+    /* Determine reply source IPv6 address. */
+#if LWIP_MULTICAST_PING
+    if (ip6_addr_ismulticast(ip6_current_dest_addr())) {
+      reply_src = ip_2_ip6(ip6_select_source_address(inp, ip6_current_src_addr()));
+      if (reply_src == NULL) {
+        /* drop */
+        pbuf_free(p);
+        pbuf_free(r);
+        ICMP6_STATS_INC(icmp6.rterr);
+        return;
+      }
+    }
+    else
+#endif /* LWIP_MULTICAST_PING */
+    {
+      reply_src = ip6_current_dest_addr();
+    }
+
+    /* Set fields in reply. */
+    ((struct icmp6_echo_hdr *)(r->payload))->type = ICMP6_TYPE_EREP;
+    ((struct icmp6_echo_hdr *)(r->payload))->chksum = 0;
+#if CHECKSUM_GEN_ICMP6
+    IF__NETIF_CHECKSUM_ENABLED(inp, NETIF_CHECKSUM_GEN_ICMP6) {
+      ((struct icmp6_echo_hdr *)(r->payload))->chksum = ip6_chksum_pseudo(r,
+          IP6_NEXTH_ICMP6, r->tot_len, reply_src, ip6_current_src_addr());
+    }
+#endif /* CHECKSUM_GEN_ICMP6 */
+
+    /* Send reply. */
+    ICMP6_STATS_INC(icmp6.xmit);
+    ip6_output_if(r, reply_src, ip6_current_src_addr(),
+        LWIP_ICMP6_HL, 0, IP6_NEXTH_ICMP6, inp);
+    pbuf_free(r);
+
+    break;
+  default:
+    ICMP6_STATS_INC(icmp6.proterr);
+    ICMP6_STATS_INC(icmp6.drop);
+    break;
+  }
+
+  pbuf_free(p);
+}
+
+
+/**
+ * Send an icmpv6 'destination unreachable' packet.
+ *
+ * This function must be used only in direct response to a packet that is being
+ * received right now. Otherwise, address zones would be lost.
+ *
+ * @param p the input packet for which the 'unreachable' should be sent,
+ *          p->payload pointing to the IPv6 header
+ * @param c ICMPv6 code for the unreachable type
+ */
+void
+icmp6_dest_unreach(struct pbuf *p, enum icmp6_dur_code c)
+{
+  icmp6_send_response(p, c, 0, ICMP6_TYPE_DUR);
+}
+
+/**
+ * Send an icmpv6 'packet too big' packet.
+ *
+ * This function must be used only in direct response to a packet that is being
+ * received right now. Otherwise, address zones would be lost.
+ *
+ * @param p the input packet for which the 'packet too big' should be sent,
+ *          p->payload pointing to the IPv6 header
+ * @param mtu the maximum mtu that we can accept
+ */
+void
+icmp6_packet_too_big(struct pbuf *p, u32_t mtu)
+{
+  icmp6_send_response(p, 0, mtu, ICMP6_TYPE_PTB);
+}
+
+/**
+ * Send an icmpv6 'time exceeded' packet.
+ *
+ * This function must be used only in direct response to a packet that is being
+ * received right now. Otherwise, address zones would be lost.
+ *
+ * @param p the input packet for which the 'time exceeded' should be sent,
+ *          p->payload pointing to the IPv6 header
+ * @param c ICMPv6 code for the time exceeded type
+ */
+void
+icmp6_time_exceeded(struct pbuf *p, enum icmp6_te_code c)
+{
+  icmp6_send_response(p, c, 0, ICMP6_TYPE_TE);
+}
+
+/**
+ * Send an icmpv6 'time exceeded' packet, with explicit source and destination
+ * addresses.
+ *
+ * This function may be used to send a response sometime after receiving the
+ * packet for which this response is meant. The provided source and destination
+ * addresses are used primarily to retain their zone information.
+ *
+ * @param p the input packet for which the 'time exceeded' should be sent,
+ *          p->payload pointing to the IPv6 header
+ * @param c ICMPv6 code for the time exceeded type
+ * @param src_addr source address of the original packet, with zone information
+ * @param dest_addr destination address of the original packet, with zone
+ *                  information
+ */
+void
+icmp6_time_exceeded_with_addrs(struct pbuf *p, enum icmp6_te_code c,
+    const ip6_addr_t *src_addr, const ip6_addr_t *dest_addr)
+{
+  icmp6_send_response_with_addrs(p, c, 0, ICMP6_TYPE_TE, src_addr, dest_addr);
+}
+
+/**
+ * Send an icmpv6 'parameter problem' packet.
+ *
+ * This function must be used only in direct response to a packet that is being
+ * received right now. Otherwise, address zones would be lost and the calculated
+ * offset would be wrong (calculated against ip6_current_header()).
+ *
+ * @param p the input packet for which the 'param problem' should be sent,
+ *          p->payload pointing to the IP header
+ * @param c ICMPv6 code for the param problem type
+ * @param pointer the pointer to the byte where the parameter is found
+ */
+void
+icmp6_param_problem(struct pbuf *p, enum icmp6_pp_code c, const void *pointer)
+{
+  u32_t pointer_u32 = (u32_t)((const u8_t *)pointer - (const u8_t *)ip6_current_header());
+  icmp6_send_response(p, c, pointer_u32, ICMP6_TYPE_PP);
+}
+
+/**
+ * Send an ICMPv6 packet in response to an incoming packet.
+ * The packet is sent *to* ip_current_src_addr() on ip_current_netif().
+ *
+ * @param p the input packet for which the response should be sent,
+ *          p->payload pointing to the IPv6 header
+ * @param code Code of the ICMPv6 header
+ * @param data Additional 32-bit parameter in the ICMPv6 header
+ * @param type Type of the ICMPv6 header
+ */
+static void
+icmp6_send_response(struct pbuf *p, u8_t code, u32_t data, u8_t type)
+{
+  const struct ip6_addr *reply_src, *reply_dest;
+  struct netif *netif = ip_current_netif();
+
+  LWIP_ASSERT("icmpv6 packet not a direct response", netif != NULL);
+  reply_dest = ip6_current_src_addr();
+
+  /* Select an address to use as source. */
+  reply_src = ip_2_ip6(ip6_select_source_address(netif, reply_dest));
+  if (reply_src == NULL) {
+    ICMP6_STATS_INC(icmp6.rterr);
+    return;
+  }
+  icmp6_send_response_with_addrs_and_netif(p, code, data, type, reply_src, reply_dest, netif);
+}
+
+/**
+ * Send an ICMPv6 packet in response to an incoming packet.
+ *
+ * Call this function if the packet is NOT sent as a direct response to an
+ * incoming packet, but rather sometime later (e.g. for a fragment reassembly
+ * timeout). The caller must provide the zoned source and destination addresses
+ * from the original packet with the src_addr and dest_addr parameters. The
+ * reason for this approach is that while the addresses themselves are part of
+ * the original packet, their zone information is not, thus possibly resulting
+ * in a link-local response being sent over the wrong link.
+ *
+ * @param p the input packet for which the response should be sent,
+ *          p->payload pointing to the IPv6 header
+ * @param code Code of the ICMPv6 header
+ * @param data Additional 32-bit parameter in the ICMPv6 header
+ * @param type Type of the ICMPv6 header
+ * @param src_addr original source address
+ * @param dest_addr original destination address
+ */
+static void
+icmp6_send_response_with_addrs(struct pbuf *p, u8_t code, u32_t data, u8_t type,
+    const ip6_addr_t *src_addr, const ip6_addr_t *dest_addr)
+{
+  const struct ip6_addr *reply_src, *reply_dest;
+  struct netif *netif;
+
+  /* Get the destination address and netif for this ICMP message. */
+  LWIP_ASSERT("must provide both source and destination", src_addr != NULL);
+  LWIP_ASSERT("must provide both source and destination", dest_addr != NULL);
+
+  /* Special case, as ip6_current_xxx is either NULL, or points
+     to a different packet than the one that expired. */
+  IP6_ADDR_ZONECHECK(src_addr);
+  IP6_ADDR_ZONECHECK(dest_addr);
+  /* Swap source and destination for the reply. */
+  reply_dest = src_addr;
+  reply_src = dest_addr;
+  netif = ip6_route(reply_src, reply_dest);
+  if (netif == NULL) {
+    ICMP6_STATS_INC(icmp6.rterr);
+    return;
+  }
+  icmp6_send_response_with_addrs_and_netif(p, code, data, type, reply_src,
+    reply_dest, netif);
+}
+
+/**
+ * Send an ICMPv6 packet (with srd/dst address and netif given).
+ *
+ * @param p the input packet for which the response should be sent,
+ *          p->payload pointing to the IPv6 header
+ * @param code Code of the ICMPv6 header
+ * @param data Additional 32-bit parameter in the ICMPv6 header
+ * @param type Type of the ICMPv6 header
+ * @param reply_src source address of the packet to send
+ * @param reply_dest destination address of the packet to send
+ * @param netif netif to send the packet
+ */
+static void
+icmp6_send_response_with_addrs_and_netif(struct pbuf *p, u8_t code, u32_t data, u8_t type,
+    const ip6_addr_t *reply_src, const ip6_addr_t *reply_dest, struct netif *netif)
+{
+  struct pbuf *q;
+  struct icmp6_hdr *icmp6hdr;
+  u16_t datalen = LWIP_MIN(p->tot_len, LWIP_ICMP6_DATASIZE);
+
+  /* ICMPv6 header + datalen (as much of the offending packet as possible) */
+  q = pbuf_alloc(PBUF_IP, sizeof(struct icmp6_hdr) + datalen,
+                 PBUF_RAM);
+  if (q == NULL) {
+    LWIP_DEBUGF(ICMP_DEBUG, ("icmp_time_exceeded: failed to allocate pbuf for ICMPv6 packet.\n"));
+    ICMP6_STATS_INC(icmp6.memerr);
+    return;
+  }
+  LWIP_ASSERT("check that first pbuf can hold icmp6 header",
+             (q->len >= (sizeof(struct icmp6_hdr))));
+
+  icmp6hdr = (struct icmp6_hdr *)q->payload;
+  icmp6hdr->type = type;
+  icmp6hdr->code = code;
+  icmp6hdr->data = lwip_htonl(data);
+
+  /* copy fields from original packet */
+  pbuf_copy_partial_pbuf(q, p, datalen, sizeof(struct icmp6_hdr));
+
+  /* calculate checksum */
+  icmp6hdr->chksum = 0;
+#if CHECKSUM_GEN_ICMP6
+  IF__NETIF_CHECKSUM_ENABLED(netif, NETIF_CHECKSUM_GEN_ICMP6) {
+    icmp6hdr->chksum = ip6_chksum_pseudo(q, IP6_NEXTH_ICMP6, q->tot_len,
+      reply_src, reply_dest);
+  }
+#endif /* CHECKSUM_GEN_ICMP6 */
+
+  ICMP6_STATS_INC(icmp6.xmit);
+  ip6_output_if(q, reply_src, reply_dest, LWIP_ICMP6_HL, 0, IP6_NEXTH_ICMP6, netif);
+  pbuf_free(q);
+}
+
+#endif /* LWIP_ICMP6 && LWIP_IPV6 */

Drivers/LwIP/src/core/ipv6/inet6.c

@@ -0,0 +1,53 @@
+/**
+ * @file
+ *
+ * INET v6 addresses.
+ */
+
+/*
+ * Copyright (c) 2010 Inico Technologies Ltd.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Ivan Delamer <delamer@inicotech.com>
+ *
+ *
+ * Please coordinate changes and requests with Ivan Delamer
+ * <delamer@inicotech.com>
+ */
+
+#include "lwip/opt.h"
+
+#if LWIP_IPV6 && LWIP_SOCKET /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/def.h"
+#include "lwip/inet.h"
+
+/** This variable is initialized by the system to contain the wildcard IPv6 address.
+ */
+const struct in6_addr in6addr_any = IN6ADDR_ANY_INIT;
+
+#endif /* LWIP_IPV6 */

Drivers/LwIP/src/core/ipv6/ip6_addr.c

@@ -0,0 +1,355 @@
+/**
+ * @file
+ *
+ * IPv6 addresses.
+ */
+
+/*
+ * Copyright (c) 2010 Inico Technologies Ltd.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Ivan Delamer <delamer@inicotech.com>
+ *
+ * Functions for handling IPv6 addresses.
+ *
+ * Please coordinate changes and requests with Ivan Delamer
+ * <delamer@inicotech.com>
+ */
+
+#include "lwip/opt.h"
+
+#if LWIP_IPV6  /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/ip_addr.h"
+#include "lwip/def.h"
+#include "lwip/netif.h"
+
+#include <string.h>
+
+#if LWIP_IPV4
+#include "lwip/ip4_addr.h" /* for ip6addr_aton to handle IPv4-mapped addresses */
+#endif /* LWIP_IPV4 */
+
+/* used by IP6_ADDR_ANY(6) in ip6_addr.h */
+const ip_addr_t ip6_addr_any = IPADDR6_INIT(0ul, 0ul, 0ul, 0ul);
+
+#define lwip_xchar(i)        ((char)((i) < 10 ? '0' + (i) : 'A' + (i) - 10))
+
+/**
+ * Check whether "cp" is a valid ascii representation
+ * of an IPv6 address and convert to a binary address.
+ * Returns 1 if the address is valid, 0 if not.
+ *
+ * @param cp IPv6 address in ascii representation (e.g. "FF01::1")
+ * @param addr pointer to which to save the ip address in network order
+ * @return 1 if cp could be converted to addr, 0 on failure
+ */
+int
+ip6addr_aton(const char *cp, ip6_addr_t *addr)
+{
+  u32_t addr_index, zero_blocks, current_block_index, current_block_value;
+  const char *s;
+#if LWIP_IPV4
+  int check_ipv4_mapped = 0;
+#endif /* LWIP_IPV4 */
+
+  /* Count the number of colons, to count the number of blocks in a "::" sequence
+     zero_blocks may be 1 even if there are no :: sequences */
+  zero_blocks = 8;
+  for (s = cp; *s != 0; s++) {
+    if (*s == ':') {
+      zero_blocks--;
+#if LWIP_IPV4
+    } else if (*s == '.') {
+      if ((zero_blocks == 5) ||(zero_blocks == 2)) {
+        check_ipv4_mapped = 1;
+        /* last block could be the start of an IPv4 address */
+        zero_blocks--;
+      } else {
+        /* invalid format */
+        return 0;
+      }
+      break;
+#endif /* LWIP_IPV4 */
+    } else if (!lwip_isxdigit(*s)) {
+      break;
+    }
+  }
+
+  /* parse each block */
+  addr_index = 0;
+  current_block_index = 0;
+  current_block_value = 0;
+  for (s = cp; *s != 0; s++) {
+    if (*s == ':') {
+      if (addr) {
+        if (current_block_index & 0x1) {
+          addr->addr[addr_index++] |= current_block_value;
+        }
+        else {
+          addr->addr[addr_index] = current_block_value << 16;
+        }
+      }
+      current_block_index++;
+#if LWIP_IPV4
+      if (check_ipv4_mapped) {
+        if (current_block_index == 6) {
+          ip4_addr_t ip4;
+          int ret = ip4addr_aton(s + 1, &ip4);
+          if (ret) {
+            if (addr) {
+              addr->addr[3] = lwip_htonl(ip4.addr);
+              current_block_index++;
+              goto fix_byte_order_and_return;
+            }
+            return 1;
+          }
+        }
+      }
+#endif /* LWIP_IPV4 */
+      current_block_value = 0;
+      if (current_block_index > 7) {
+        /* address too long! */
+        return 0;
+      }
+      if (s[1] == ':') {
+        if (s[2] == ':') {
+          /* invalid format: three successive colons */
+          return 0;
+        }
+        s++;
+        /* "::" found, set zeros */
+        while (zero_blocks > 0) {
+          zero_blocks--;
+          if (current_block_index & 0x1) {
+            addr_index++;
+          } else {
+            if (addr) {
+              addr->addr[addr_index] = 0;
+            }
+          }
+          current_block_index++;
+          if (current_block_index > 7) {
+            /* address too long! */
+            return 0;
+          }
+        }
+      }
+    } else if (lwip_isxdigit(*s)) {
+      /* add current digit */
+      current_block_value = (current_block_value << 4) +
+          (lwip_isdigit(*s) ? (u32_t)(*s - '0') :
+          (u32_t)(10 + (lwip_islower(*s) ? *s - 'a' : *s - 'A')));
+    } else {
+      /* unexpected digit, space? CRLF? */
+      break;
+    }
+  }
+
+  if (addr) {
+    if (current_block_index & 0x1) {
+      addr->addr[addr_index++] |= current_block_value;
+    }
+    else {
+      addr->addr[addr_index] = current_block_value << 16;
+    }
+#if LWIP_IPV4
+fix_byte_order_and_return:
+#endif
+    /* convert to network byte order. */
+    for (addr_index = 0; addr_index < 4; addr_index++) {
+      addr->addr[addr_index] = lwip_htonl(addr->addr[addr_index]);
+    }
+
+    ip6_addr_clear_zone(addr);
+#if LWIP_IPV6_SCOPES
+    if (*s == '%') {
+      const char *scopestr = s + 1;
+      if (*scopestr) {
+        struct netif *netif = netif_find(scopestr);
+        if (netif) {
+          ip6_addr_assign_zone(addr, IP6_UNKNOWN, netif);
+        }
+      }
+    }
+#endif
+  }
+
+  if (current_block_index != 7) {
+    return 0;
+  }
+
+  return 1;
+}
+
+/**
+ * Convert numeric IPv6 address into ASCII representation.
+ * returns ptr to static buffer; not reentrant!
+ *
+ * @param addr ip6 address in network order to convert
+ * @return pointer to a global static (!) buffer that holds the ASCII
+ *         representation of addr
+ */
+char *
+ip6addr_ntoa(const ip6_addr_t *addr)
+{
+  static char str[40];
+  return ip6addr_ntoa_r(addr, str, 40);
+}
+
+/**
+ * Same as ipaddr_ntoa, but reentrant since a user-supplied buffer is used.
+ *
+ * @param addr ip6 address in network order to convert
+ * @param buf target buffer where the string is stored
+ * @param buflen length of buf
+ * @return either pointer to buf which now holds the ASCII
+ *         representation of addr or NULL if buf was too small
+ */
+char *
+ip6addr_ntoa_r(const ip6_addr_t *addr, char *buf, int buflen)
+{
+  u32_t current_block_index, current_block_value, next_block_value;
+  s32_t i;
+  u8_t zero_flag, empty_block_flag;
+
+#if LWIP_IPV4
+  if (ip6_addr_isipv4mappedipv6(addr)) {
+    /* This is an IPv4 mapped address */
+    ip4_addr_t addr4;
+    char *ret;
+#define IP4MAPPED_HEADER "::FFFF:"
+    char *buf_ip4 = buf + sizeof(IP4MAPPED_HEADER) - 1;
+    int buflen_ip4 = buflen - sizeof(IP4MAPPED_HEADER) + 1;
+    if (buflen < (int)sizeof(IP4MAPPED_HEADER)) {
+      return NULL;
+    }
+    memcpy(buf, IP4MAPPED_HEADER, sizeof(IP4MAPPED_HEADER));
+    addr4.addr = addr->addr[3];
+    ret = ip4addr_ntoa_r(&addr4, buf_ip4, buflen_ip4);
+    if (ret != buf_ip4) {
+      return NULL;
+    }
+    return buf;
+  }
+#endif /* LWIP_IPV4 */
+  i = 0;
+  empty_block_flag = 0; /* used to indicate a zero chain for "::' */
+
+  for (current_block_index = 0; current_block_index < 8; current_block_index++) {
+    /* get the current 16-bit block */
+    current_block_value = lwip_htonl(addr->addr[current_block_index >> 1]);
+    if ((current_block_index & 0x1) == 0) {
+      current_block_value = current_block_value >> 16;
+    }
+    current_block_value &= 0xffff;
+
+    /* Check for empty block. */
+    if (current_block_value == 0) {
+      if (current_block_index == 7 && empty_block_flag == 1) {
+        /* special case, we must render a ':' for the last block. */
+        buf[i++] = ':';
+        if (i >= buflen) {
+          return NULL;
+        }
+        break;
+      }
+      if (empty_block_flag == 0) {
+        /* generate empty block "::", but only if more than one contiguous zero block,
+         * according to current formatting suggestions RFC 5952. */
+        next_block_value = lwip_htonl(addr->addr[(current_block_index + 1) >> 1]);
+        if ((current_block_index & 0x1) == 0x01) {
+            next_block_value = next_block_value >> 16;
+        }
+        next_block_value &= 0xffff;
+        if (next_block_value == 0) {
+          empty_block_flag = 1;
+          buf[i++] = ':';
+          if (i >= buflen) {
+            return NULL;
+          }
+          continue; /* move on to next block. */
+        }
+      } else if (empty_block_flag == 1) {
+        /* move on to next block. */
+        continue;
+      }
+    } else if (empty_block_flag == 1) {
+      /* Set this flag value so we don't produce multiple empty blocks. */
+      empty_block_flag = 2;
+    }
+
+    if (current_block_index > 0) {
+      buf[i++] = ':';
+      if (i >= buflen) {
+        return NULL;
+      }
+    }
+
+    if ((current_block_value & 0xf000) == 0) {
+      zero_flag = 1;
+    } else {
+      buf[i++] = lwip_xchar(((current_block_value & 0xf000) >> 12));
+      zero_flag = 0;
+      if (i >= buflen) {
+        return NULL;
+      }
+    }
+
+    if (((current_block_value & 0xf00) == 0) && (zero_flag)) {
+      /* do nothing */
+    } else {
+      buf[i++] = lwip_xchar(((current_block_value & 0xf00) >> 8));
+      zero_flag = 0;
+      if (i >= buflen) {
+        return NULL;
+      }
+    }
+
+    if (((current_block_value & 0xf0) == 0) && (zero_flag)) {
+      /* do nothing */
+    }
+    else {
+      buf[i++] = lwip_xchar(((current_block_value & 0xf0) >> 4));
+      zero_flag = 0;
+      if (i >= buflen) {
+        return NULL;
+      }
+    }
+
+    buf[i++] = lwip_xchar((current_block_value & 0xf));
+    if (i >= buflen) {
+      return NULL;
+    }
+  }
+
+  buf[i] = 0;
+
+  return buf;
+}
+
+#endif /* LWIP_IPV6 */

Drivers/LwIP/src/core/ipv6/ip6_frag.c

@@ -0,0 +1,862 @@
+/**
+ * @file
+ *
+ * IPv6 fragmentation and reassembly.
+ */
+
+/*
+ * Copyright (c) 2010 Inico Technologies Ltd.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Ivan Delamer <delamer@inicotech.com>
+ *
+ *
+ * Please coordinate changes and requests with Ivan Delamer
+ * <delamer@inicotech.com>
+ */
+
+#include "lwip/opt.h"
+#include "lwip/ip6_frag.h"
+#include "lwip/ip6.h"
+#include "lwip/icmp6.h"
+#include "lwip/nd6.h"
+#include "lwip/ip.h"
+
+#include "lwip/pbuf.h"
+#include "lwip/memp.h"
+#include "lwip/stats.h"
+
+#include <string.h>
+
+#if LWIP_IPV6 && LWIP_IPV6_REASS  /* don't build if not configured for use in lwipopts.h */
+
+
+/** Setting this to 0, you can turn off checking the fragments for overlapping
+ * regions. The code gets a little smaller. Only use this if you know that
+ * overlapping won't occur on your network! */
+#ifndef IP_REASS_CHECK_OVERLAP
+#define IP_REASS_CHECK_OVERLAP 1
+#endif /* IP_REASS_CHECK_OVERLAP */
+
+/** Set to 0 to prevent freeing the oldest datagram when the reassembly buffer is
+ * full (IP_REASS_MAX_PBUFS pbufs are enqueued). The code gets a little smaller.
+ * Datagrams will be freed by timeout only. Especially useful when MEMP_NUM_REASSDATA
+ * is set to 1, so one datagram can be reassembled at a time, only. */
+#ifndef IP_REASS_FREE_OLDEST
+#define IP_REASS_FREE_OLDEST 1
+#endif /* IP_REASS_FREE_OLDEST */
+
+#if IPV6_FRAG_COPYHEADER
+/* The number of bytes we need to "borrow" from (i.e., overwrite in) the header
+ * that precedes the fragment header for reassembly pruposes. */
+#define IPV6_FRAG_REQROOM ((s16_t)(sizeof(struct ip6_reass_helper) - IP6_FRAG_HLEN))
+#endif
+
+#define IP_REASS_FLAG_LASTFRAG 0x01
+
+/** This is a helper struct which holds the starting
+ * offset and the ending offset of this fragment to
+ * easily chain the fragments.
+ * It has the same packing requirements as the IPv6 header, since it replaces
+ * the Fragment Header in memory in incoming fragments to keep
+ * track of the various fragments.
+ */
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/bpstruct.h"
+#endif
+PACK_STRUCT_BEGIN
+struct ip6_reass_helper {
+  PACK_STRUCT_FIELD(struct pbuf *next_pbuf);
+  PACK_STRUCT_FIELD(u16_t start);
+  PACK_STRUCT_FIELD(u16_t end);
+} PACK_STRUCT_STRUCT;
+PACK_STRUCT_END
+#ifdef PACK_STRUCT_USE_INCLUDES
+#  include "arch/epstruct.h"
+#endif
+
+/* static variables */
+static struct ip6_reassdata *reassdatagrams;
+static u16_t ip6_reass_pbufcount;
+
+/* Forward declarations. */
+static void ip6_reass_free_complete_datagram(struct ip6_reassdata *ipr);
+#if IP_REASS_FREE_OLDEST
+static void ip6_reass_remove_oldest_datagram(struct ip6_reassdata *ipr, int pbufs_needed);
+#endif /* IP_REASS_FREE_OLDEST */
+
+void
+ip6_reass_tmr(void)
+{
+  struct ip6_reassdata *r, *tmp;
+
+#if !IPV6_FRAG_COPYHEADER
+  LWIP_ASSERT("sizeof(struct ip6_reass_helper) <= IP6_FRAG_HLEN, set IPV6_FRAG_COPYHEADER to 1",
+    sizeof(struct ip6_reass_helper) <= IP6_FRAG_HLEN);
+#endif /* !IPV6_FRAG_COPYHEADER */
+
+  r = reassdatagrams;
+  while (r != NULL) {
+    /* Decrement the timer. Once it reaches 0,
+     * clean up the incomplete fragment assembly */
+    if (r->timer > 0) {
+      r->timer--;
+      r = r->next;
+    } else {
+      /* reassembly timed out */
+      tmp = r;
+      /* get the next pointer before freeing */
+      r = r->next;
+      /* free the helper struct and all enqueued pbufs */
+      ip6_reass_free_complete_datagram(tmp);
+     }
+   }
+}
+
+/**
+ * Free a datagram (struct ip6_reassdata) and all its pbufs.
+ * Updates the total count of enqueued pbufs (ip6_reass_pbufcount),
+ * sends an ICMP time exceeded packet.
+ *
+ * @param ipr datagram to free
+ */
+static void
+ip6_reass_free_complete_datagram(struct ip6_reassdata *ipr)
+{
+  struct ip6_reassdata *prev;
+  u16_t pbufs_freed = 0;
+  u16_t clen;
+  struct pbuf *p;
+  struct ip6_reass_helper *iprh;
+
+#if LWIP_ICMP6
+  iprh = (struct ip6_reass_helper *)ipr->p->payload;
+  if (iprh->start == 0) {
+    /* The first fragment was received, send ICMP time exceeded. */
+    /* First, de-queue the first pbuf from r->p. */
+    p = ipr->p;
+    ipr->p = iprh->next_pbuf;
+    /* Restore the part that we've overwritten with our helper structure, or we
+     * might send garbage (and disclose a pointer) in the ICMPv6 reply. */
+    MEMCPY(p->payload, ipr->orig_hdr, sizeof(iprh));
+    /* Then, move back to the original ipv6 header (we are now pointing to Fragment header).
+       This cannot fail since we already checked when receiving this fragment. */
+    if (pbuf_header_force(p, (s16_t)((u8_t*)p->payload - (u8_t*)ipr->iphdr))) {
+      LWIP_ASSERT("ip6_reass_free: moving p->payload to ip6 header failed", 0);
+    }
+    else {
+      /* Reconstruct the zoned source and destination addresses, so that we do
+       * not end up sending the ICMP response over the wrong link. */
+      ip6_addr_t src_addr, dest_addr;
+      ip6_addr_copy_from_packed(src_addr, IPV6_FRAG_SRC(ipr));
+      ip6_addr_set_zone(&src_addr, ipr->src_zone);
+      ip6_addr_copy_from_packed(dest_addr, IPV6_FRAG_DEST(ipr));
+      ip6_addr_set_zone(&dest_addr, ipr->dest_zone);
+      /* Send the actual ICMP response. */
+      icmp6_time_exceeded_with_addrs(p, ICMP6_TE_FRAG, &src_addr, &dest_addr);
+    }
+    clen = pbuf_clen(p);
+    LWIP_ASSERT("pbufs_freed + clen <= 0xffff", pbufs_freed + clen <= 0xffff);
+    pbufs_freed = (u16_t)(pbufs_freed + clen);
+    pbuf_free(p);
+  }
+#endif /* LWIP_ICMP6 */
+
+  /* First, free all received pbufs.  The individual pbufs need to be released
+     separately as they have not yet been chained */
+  p = ipr->p;
+  while (p != NULL) {
+    struct pbuf *pcur;
+    iprh = (struct ip6_reass_helper *)p->payload;
+    pcur = p;
+    /* get the next pointer before freeing */
+    p = iprh->next_pbuf;
+    clen = pbuf_clen(pcur);
+    LWIP_ASSERT("pbufs_freed + clen <= 0xffff", pbufs_freed + clen <= 0xffff);
+    pbufs_freed = (u16_t)(pbufs_freed + clen);
+    pbuf_free(pcur);
+  }
+
+  /* Then, unchain the struct ip6_reassdata from the list and free it. */
+  if (ipr == reassdatagrams) {
+    reassdatagrams = ipr->next;
+  } else {
+    prev = reassdatagrams;
+    while (prev != NULL) {
+      if (prev->next == ipr) {
+        break;
+      }
+      prev = prev->next;
+    }
+    if (prev != NULL) {
+      prev->next = ipr->next;
+    }
+  }
+  memp_free(MEMP_IP6_REASSDATA, ipr);
+
+  /* Finally, update number of pbufs in reassembly queue */
+  LWIP_ASSERT("ip_reass_pbufcount >= clen", ip6_reass_pbufcount >= pbufs_freed);
+  ip6_reass_pbufcount = (u16_t)(ip6_reass_pbufcount - pbufs_freed);
+}
+
+#if IP_REASS_FREE_OLDEST
+/**
+ * Free the oldest datagram to make room for enqueueing new fragments.
+ * The datagram ipr is not freed!
+ *
+ * @param ipr ip6_reassdata for the current fragment
+ * @param pbufs_needed number of pbufs needed to enqueue
+ *        (used for freeing other datagrams if not enough space)
+ */
+static void
+ip6_reass_remove_oldest_datagram(struct ip6_reassdata *ipr, int pbufs_needed)
+{
+  struct ip6_reassdata *r, *oldest;
+
+  /* Free datagrams until being allowed to enqueue 'pbufs_needed' pbufs,
+   * but don't free the current datagram! */
+  do {
+    r = oldest = reassdatagrams;
+    while (r != NULL) {
+      if (r != ipr) {
+        if (r->timer <= oldest->timer) {
+          /* older than the previous oldest */
+          oldest = r;
+        }
+      }
+      r = r->next;
+    }
+    if (oldest == ipr) {
+      /* nothing to free, ipr is the only element on the list */
+      return;
+    }
+    if (oldest != NULL) {
+      ip6_reass_free_complete_datagram(oldest);
+    }
+  } while (((ip6_reass_pbufcount + pbufs_needed) > IP_REASS_MAX_PBUFS) && (reassdatagrams != NULL));
+}
+#endif /* IP_REASS_FREE_OLDEST */
+
+/**
+ * Reassembles incoming IPv6 fragments into an IPv6 datagram.
+ *
+ * @param p points to the IPv6 Fragment Header
+ * @return NULL if reassembly is incomplete, pbuf pointing to
+ *         IPv6 Header if reassembly is complete
+ */
+struct pbuf *
+ip6_reass(struct pbuf *p)
+{
+  struct ip6_reassdata *ipr, *ipr_prev;
+  struct ip6_reass_helper *iprh, *iprh_tmp, *iprh_prev=NULL;
+  struct ip6_frag_hdr *frag_hdr;
+  u16_t offset, len, start, end;
+  ptrdiff_t hdrdiff;
+  u16_t clen;
+  u8_t valid = 1;
+  struct pbuf *q, *next_pbuf;
+
+  IP6_FRAG_STATS_INC(ip6_frag.recv);
+
+  /* ip6_frag_hdr must be in the first pbuf, not chained. Checked by caller. */
+  LWIP_ASSERT("IPv6 fragment header does not fit in first pbuf",
+    p->len >= sizeof(struct ip6_frag_hdr));
+
+  frag_hdr = (struct ip6_frag_hdr *) p->payload;
+
+  clen = pbuf_clen(p);
+
+  offset = lwip_ntohs(frag_hdr->_fragment_offset);
+
+  /* Calculate fragment length from IPv6 payload length.
+   * Adjust for headers before Fragment Header.
+   * And finally adjust by Fragment Header length. */
+  len = lwip_ntohs(ip6_current_header()->_plen);
+  hdrdiff = (u8_t*)p->payload - (const u8_t*)ip6_current_header();
+  LWIP_ASSERT("not a valid pbuf (ip6_input check missing?)", hdrdiff <= 0xFFFF);
+  LWIP_ASSERT("not a valid pbuf (ip6_input check missing?)", hdrdiff >= IP6_HLEN);
+  hdrdiff -= IP6_HLEN;
+  hdrdiff += IP6_FRAG_HLEN;
+  if (hdrdiff > len) {
+    IP6_FRAG_STATS_INC(ip6_frag.proterr);
+    goto nullreturn;
+  }
+  len = (u16_t)(len - hdrdiff);
+  start = (offset & IP6_FRAG_OFFSET_MASK);
+  if (start > (0xFFFF - len)) {
+    /* u16_t overflow, cannot handle this */
+    IP6_FRAG_STATS_INC(ip6_frag.proterr);
+    goto nullreturn;
+  }
+
+  /* Look for the datagram the fragment belongs to in the current datagram queue,
+   * remembering the previous in the queue for later dequeueing. */
+  for (ipr = reassdatagrams, ipr_prev = NULL; ipr != NULL; ipr = ipr->next) {
+    /* Check if the incoming fragment matches the one currently present
+       in the reassembly buffer. If so, we proceed with copying the
+       fragment into the buffer. */
+    if ((frag_hdr->_identification == ipr->identification) &&
+        ip6_addr_packed_eq(ip6_current_src_addr(), &(IPV6_FRAG_SRC(ipr)), ipr->src_zone) &&
+        ip6_addr_packed_eq(ip6_current_dest_addr(), &(IPV6_FRAG_DEST(ipr)), ipr->dest_zone)) {
+      IP6_FRAG_STATS_INC(ip6_frag.cachehit);
+      break;
+    }
+    ipr_prev = ipr;
+  }
+
+  if (ipr == NULL) {
+  /* Enqueue a new datagram into the datagram queue */
+    ipr = (struct ip6_reassdata *)memp_malloc(MEMP_IP6_REASSDATA);
+    if (ipr == NULL) {
+#if IP_REASS_FREE_OLDEST
+      /* Make room and try again. */
+      ip6_reass_remove_oldest_datagram(ipr, clen);
+      ipr = (struct ip6_reassdata *)memp_malloc(MEMP_IP6_REASSDATA);
+      if (ipr != NULL) {
+        /* re-search ipr_prev since it might have been removed */
+        for (ipr_prev = reassdatagrams; ipr_prev != NULL; ipr_prev = ipr_prev->next) {
+          if (ipr_prev->next == ipr) {
+            break;
+          }
+        }
+      } else
+#endif /* IP_REASS_FREE_OLDEST */
+      {
+        IP6_FRAG_STATS_INC(ip6_frag.memerr);
+        goto nullreturn;
+      }
+    }
+
+    memset(ipr, 0, sizeof(struct ip6_reassdata));
+    ipr->timer = IPV6_REASS_MAXAGE;
+
+    /* enqueue the new structure to the front of the list */
+    ipr->next = reassdatagrams;
+    reassdatagrams = ipr;
+
+    /* Use the current IPv6 header for src/dest address reference.
+     * Eventually, we will replace it when we get the first fragment
+     * (it might be this one, in any case, it is done later). */
+    /* need to use the none-const pointer here: */
+    ipr->iphdr = ip_data.current_ip6_header;
+#if IPV6_FRAG_COPYHEADER
+    MEMCPY(&ipr->src, &ip6_current_header()->src, sizeof(ipr->src));
+    MEMCPY(&ipr->dest, &ip6_current_header()->dest, sizeof(ipr->dest));
+#endif /* IPV6_FRAG_COPYHEADER */
+#if LWIP_IPV6_SCOPES
+    /* Also store the address zone information.
+     * @todo It is possible that due to netif destruction and recreation, the
+     * stored zones end up resolving to a different interface. In that case, we
+     * risk sending a "time exceeded" ICMP response over the wrong link.
+     * Ideally, netif destruction would clean up matching pending reassembly
+     * structures, but custom zone mappings would make that non-trivial. */
+    ipr->src_zone = ip6_addr_zone(ip6_current_src_addr());
+    ipr->dest_zone = ip6_addr_zone(ip6_current_dest_addr());
+#endif /* LWIP_IPV6_SCOPES */
+    /* copy the fragmented packet id. */
+    ipr->identification = frag_hdr->_identification;
+
+    /* copy the nexth field */
+    ipr->nexth = frag_hdr->_nexth;
+  }
+
+  /* Check if we are allowed to enqueue more datagrams. */
+  if ((ip6_reass_pbufcount + clen) > IP_REASS_MAX_PBUFS) {
+#if IP_REASS_FREE_OLDEST
+    ip6_reass_remove_oldest_datagram(ipr, clen);
+    if ((ip6_reass_pbufcount + clen) <= IP_REASS_MAX_PBUFS) {
+      /* re-search ipr_prev since it might have been removed */
+      for (ipr_prev = reassdatagrams; ipr_prev != NULL; ipr_prev = ipr_prev->next) {
+        if (ipr_prev->next == ipr) {
+          break;
+        }
+      }
+    } else
+#endif /* IP_REASS_FREE_OLDEST */
+    {
+      /* @todo: send ICMPv6 time exceeded here? */
+      /* drop this pbuf */
+      IP6_FRAG_STATS_INC(ip6_frag.memerr);
+      goto nullreturn;
+    }
+  }
+
+  /* Overwrite Fragment Header with our own helper struct. */
+#if IPV6_FRAG_COPYHEADER
+  if (IPV6_FRAG_REQROOM > 0) {
+    /* Make room for struct ip6_reass_helper (only required if sizeof(void*) > 4).
+       This cannot fail since we already checked when receiving this fragment. */
+    u8_t hdrerr = pbuf_header_force(p, IPV6_FRAG_REQROOM);
+    LWIP_UNUSED_ARG(hdrerr); /* in case of LWIP_NOASSERT */
+    LWIP_ASSERT("no room for struct ip6_reass_helper", hdrerr == 0);
+  }
+#else /* IPV6_FRAG_COPYHEADER */
+  LWIP_ASSERT("sizeof(struct ip6_reass_helper) <= IP6_FRAG_HLEN, set IPV6_FRAG_COPYHEADER to 1",
+    sizeof(struct ip6_reass_helper) <= IP6_FRAG_HLEN);
+#endif /* IPV6_FRAG_COPYHEADER */
+
+  /* Prepare the pointer to the helper structure, and its initial values.
+   * Do not yet write to the structure itself, as we still have to make a
+   * backup of the original data, and we should not do that until we know for
+   * sure that we are going to add this packet to the list. */
+  iprh = (struct ip6_reass_helper *)p->payload;
+  next_pbuf = NULL;
+  end = (u16_t)(start + len);
+
+  /* find the right place to insert this pbuf */
+  /* Iterate through until we either get to the end of the list (append),
+   * or we find on with a larger offset (insert). */
+  for (q = ipr->p; q != NULL;) {
+    iprh_tmp = (struct ip6_reass_helper*)q->payload;
+    if (start < iprh_tmp->start) {
+#if IP_REASS_CHECK_OVERLAP
+      if (end > iprh_tmp->start) {
+        /* fragment overlaps with following, throw away */
+        IP6_FRAG_STATS_INC(ip6_frag.proterr);
+        goto nullreturn;
+      }
+      if (iprh_prev != NULL) {
+        if (start < iprh_prev->end) {
+          /* fragment overlaps with previous, throw away */
+          IP6_FRAG_STATS_INC(ip6_frag.proterr);
+          goto nullreturn;
+        }
+      }
+#endif /* IP_REASS_CHECK_OVERLAP */
+      /* the new pbuf should be inserted before this */
+      next_pbuf = q;
+      if (iprh_prev != NULL) {
+        /* not the fragment with the lowest offset */
+        iprh_prev->next_pbuf = p;
+      } else {
+        /* fragment with the lowest offset */
+        ipr->p = p;
+      }
+      break;
+    } else if (start == iprh_tmp->start) {
+      /* received the same datagram twice: no need to keep the datagram */
+      goto nullreturn;
+#if IP_REASS_CHECK_OVERLAP
+    } else if (start < iprh_tmp->end) {
+      /* overlap: no need to keep the new datagram */
+      IP6_FRAG_STATS_INC(ip6_frag.proterr);
+      goto nullreturn;
+#endif /* IP_REASS_CHECK_OVERLAP */
+    } else {
+      /* Check if the fragments received so far have no gaps. */
+      if (iprh_prev != NULL) {
+        if (iprh_prev->end != iprh_tmp->start) {
+          /* There is a fragment missing between the current
+           * and the previous fragment */
+          valid = 0;
+        }
+      }
+    }
+    q = iprh_tmp->next_pbuf;
+    iprh_prev = iprh_tmp;
+  }
+
+  /* If q is NULL, then we made it to the end of the list. Determine what to do now */
+  if (q == NULL) {
+    if (iprh_prev != NULL) {
+      /* this is (for now), the fragment with the highest offset:
+       * chain it to the last fragment */
+#if IP_REASS_CHECK_OVERLAP
+      LWIP_ASSERT("check fragments don't overlap", iprh_prev->end <= start);
+#endif /* IP_REASS_CHECK_OVERLAP */
+      iprh_prev->next_pbuf = p;
+      if (iprh_prev->end != start) {
+        valid = 0;
+      }
+    } else {
+#if IP_REASS_CHECK_OVERLAP
+      LWIP_ASSERT("no previous fragment, this must be the first fragment!",
+        ipr->p == NULL);
+#endif /* IP_REASS_CHECK_OVERLAP */
+      /* this is the first fragment we ever received for this ip datagram */
+      ipr->p = p;
+    }
+  }
+
+  /* Track the current number of pbufs current 'in-flight', in order to limit
+  the number of fragments that may be enqueued at any one time */
+  ip6_reass_pbufcount = (u16_t)(ip6_reass_pbufcount + clen);
+
+  /* Remember IPv6 header if this is the first fragment. */
+  if (start == 0) {
+    /* need to use the none-const pointer here: */
+    ipr->iphdr = ip_data.current_ip6_header;
+    /* Make a backup of the part of the packet data that we are about to
+     * overwrite, so that we can restore the original later. */
+    MEMCPY(ipr->orig_hdr, p->payload, sizeof(*iprh));
+    /* For IPV6_FRAG_COPYHEADER there is no need to copy src/dst again, as they
+     * will be the same as they were. With LWIP_IPV6_SCOPES, the same applies
+     * to the source/destination zones. */
+  }
+  /* Only after the backup do we get to fill in the actual helper structure. */
+  iprh->next_pbuf = next_pbuf;
+  iprh->start = start;
+  iprh->end = end;
+
+  /* If this is the last fragment, calculate total packet length. */
+  if ((offset & IP6_FRAG_MORE_FLAG) == 0) {
+    ipr->datagram_len = iprh->end;
+  }
+
+  /* Additional validity tests: we have received first and last fragment. */
+  iprh_tmp = (struct ip6_reass_helper*)ipr->p->payload;
+  if (iprh_tmp->start != 0) {
+    valid = 0;
+  }
+  if (ipr->datagram_len == 0) {
+    valid = 0;
+  }
+
+  /* Final validity test: no gaps between current and last fragment. */
+  iprh_prev = iprh;
+  q = iprh->next_pbuf;
+  while ((q != NULL) && valid) {
+    iprh = (struct ip6_reass_helper*)q->payload;
+    if (iprh_prev->end != iprh->start) {
+      valid = 0;
+      break;
+    }
+    iprh_prev = iprh;
+    q = iprh->next_pbuf;
+  }
+
+  if (valid) {
+    /* All fragments have been received */
+    struct ip6_hdr* iphdr_ptr;
+
+    /* chain together the pbufs contained within the ip6_reassdata list. */
+    iprh = (struct ip6_reass_helper*) ipr->p->payload;
+    while (iprh != NULL) {
+      next_pbuf = iprh->next_pbuf;
+      if (next_pbuf != NULL) {
+        /* Save next helper struct (will be hidden in next step). */
+        iprh_tmp = (struct ip6_reass_helper*)next_pbuf->payload;
+
+        /* hide the fragment header for every succeeding fragment */
+        pbuf_remove_header(next_pbuf, IP6_FRAG_HLEN);
+#if IPV6_FRAG_COPYHEADER
+        if (IPV6_FRAG_REQROOM > 0) {
+          /* hide the extra bytes borrowed from ip6_hdr for struct ip6_reass_helper */
+          u8_t hdrerr = pbuf_remove_header(next_pbuf, IPV6_FRAG_REQROOM);
+          LWIP_UNUSED_ARG(hdrerr); /* in case of LWIP_NOASSERT */
+          LWIP_ASSERT("no room for struct ip6_reass_helper", hdrerr == 0);
+        }
+#endif
+        pbuf_cat(ipr->p, next_pbuf);
+      }
+      else {
+        iprh_tmp = NULL;
+      }
+
+      iprh = iprh_tmp;
+    }
+
+    /* Get the first pbuf. */
+    p = ipr->p;
+
+#if IPV6_FRAG_COPYHEADER
+    if (IPV6_FRAG_REQROOM > 0) {
+      u8_t hdrerr;
+      /* Restore (only) the bytes that we overwrote beyond the fragment header.
+       * Those bytes may belong to either the IPv6 header or an extension
+       * header placed before the fragment header. */
+      MEMCPY(p->payload, ipr->orig_hdr, IPV6_FRAG_REQROOM);
+      /* get back room for struct ip6_reass_helper (only required if sizeof(void*) > 4) */
+      hdrerr = pbuf_remove_header(p, IPV6_FRAG_REQROOM);
+      LWIP_UNUSED_ARG(hdrerr); /* in case of LWIP_NOASSERT */
+      LWIP_ASSERT("no room for struct ip6_reass_helper", hdrerr == 0);
+    }
+#endif
+
+    /* We need to get rid of the fragment header itself, which is somewhere in
+     * the middle of the packet (but still in the first pbuf of the chain).
+     * Getting rid of the header is required by RFC 2460 Sec. 4.5 and necessary
+     * in order to be able to reassemble packets that are close to full size
+     * (i.e., around 65535 bytes). We simply move up all the headers before the
+     * fragment header, including the IPv6 header, and adjust the payload start
+     * accordingly. This works because all these headers are in the first pbuf
+     * of the chain, and because the caller adjusts all its pointers on
+     * successful reassembly. */
+    MEMMOVE((u8_t*)ipr->iphdr + sizeof(struct ip6_frag_hdr), ipr->iphdr,
+      (size_t)((u8_t*)p->payload - (u8_t*)ipr->iphdr));
+
+    /* This is where the IPv6 header is now. */
+    iphdr_ptr = (struct ip6_hdr*)((u8_t*)ipr->iphdr +
+      sizeof(struct ip6_frag_hdr));
+
+    /* Adjust datagram length by adding header lengths. */
+    ipr->datagram_len = (u16_t)(ipr->datagram_len + ((u8_t*)p->payload - (u8_t*)iphdr_ptr)
+                         - IP6_HLEN);
+
+    /* Set payload length in ip header. */
+    iphdr_ptr->_plen = lwip_htons(ipr->datagram_len);
+
+    /* With the fragment header gone, we now need to adjust the next-header
+     * field of whatever header was originally before it. Since the packet made
+     * it through the original header processing routines at least up to the
+     * fragment header, we do not need any further sanity checks here. */
+    if (IP6H_NEXTH(iphdr_ptr) == IP6_NEXTH_FRAGMENT) {
+      iphdr_ptr->_nexth = ipr->nexth;
+    } else {
+      u8_t *ptr = (u8_t *)iphdr_ptr + IP6_HLEN;
+      while (*ptr != IP6_NEXTH_FRAGMENT) {
+        ptr += 8 * (1 + ptr[1]);
+      }
+      *ptr = ipr->nexth;
+    }
+
+    /* release the resources allocated for the fragment queue entry */
+    if (reassdatagrams == ipr) {
+      /* it was the first in the list */
+      reassdatagrams = ipr->next;
+    } else {
+      /* it wasn't the first, so it must have a valid 'prev' */
+      LWIP_ASSERT("sanity check linked list", ipr_prev != NULL);
+      ipr_prev->next = ipr->next;
+    }
+    memp_free(MEMP_IP6_REASSDATA, ipr);
+
+    /* adjust the number of pbufs currently queued for reassembly. */
+    clen = pbuf_clen(p);
+    LWIP_ASSERT("ip6_reass_pbufcount >= clen", ip6_reass_pbufcount >= clen);
+    ip6_reass_pbufcount = (u16_t)(ip6_reass_pbufcount - clen);
+
+    /* Move pbuf back to IPv6 header. This should never fail. */
+    if (pbuf_header_force(p, (s16_t)((u8_t*)p->payload - (u8_t*)iphdr_ptr))) {
+      LWIP_ASSERT("ip6_reass: moving p->payload to ip6 header failed", 0);
+      pbuf_free(p);
+      return NULL;
+    }
+
+    /* Return the pbuf chain */
+    return p;
+  }
+  /* the datagram is not (yet?) reassembled completely */
+  return NULL;
+
+nullreturn:
+  IP6_FRAG_STATS_INC(ip6_frag.drop);
+  pbuf_free(p);
+  return NULL;
+}
+
+#endif /* LWIP_IPV6 && LWIP_IPV6_REASS */
+
+#if LWIP_IPV6 && LWIP_IPV6_FRAG
+
+#if !LWIP_NETIF_TX_SINGLE_PBUF
+/** Allocate a new struct pbuf_custom_ref */
+static struct pbuf_custom_ref*
+ip6_frag_alloc_pbuf_custom_ref(void)
+{
+  return (struct pbuf_custom_ref*)memp_malloc(MEMP_FRAG_PBUF);
+}
+
+/** Free a struct pbuf_custom_ref */
+static void
+ip6_frag_free_pbuf_custom_ref(struct pbuf_custom_ref* p)
+{
+  LWIP_ASSERT("p != NULL", p != NULL);
+  memp_free(MEMP_FRAG_PBUF, p);
+}
+
+/** Free-callback function to free a 'struct pbuf_custom_ref', called by
+ * pbuf_free. */
+static void
+ip6_frag_free_pbuf_custom(struct pbuf *p)
+{
+  struct pbuf_custom_ref *pcr = (struct pbuf_custom_ref*)p;
+  LWIP_ASSERT("pcr != NULL", pcr != NULL);
+  LWIP_ASSERT("pcr == p", (void*)pcr == (void*)p);
+  if (pcr->original != NULL) {
+    pbuf_free(pcr->original);
+  }
+  ip6_frag_free_pbuf_custom_ref(pcr);
+}
+#endif /* !LWIP_NETIF_TX_SINGLE_PBUF */
+
+/**
+ * Fragment an IPv6 datagram if too large for the netif or path MTU.
+ *
+ * Chop the datagram in MTU sized chunks and send them in order
+ * by pointing PBUF_REFs into p
+ *
+ * @param p ipv6 packet to send
+ * @param netif the netif on which to send
+ * @param dest destination ipv6 address to which to send
+ *
+ * @return ERR_OK if sent successfully, err_t otherwise
+ */
+err_t
+ip6_frag(struct pbuf *p, struct netif *netif, const ip6_addr_t *dest)
+{
+  struct ip6_hdr *original_ip6hdr;
+  struct ip6_hdr *ip6hdr;
+  struct ip6_frag_hdr *frag_hdr;
+  struct pbuf *rambuf;
+#if !LWIP_NETIF_TX_SINGLE_PBUF
+  struct pbuf *newpbuf;
+  u16_t newpbuflen = 0;
+  u16_t left_to_copy;
+#endif
+  static u32_t identification;
+  u16_t left, cop;
+  const u16_t mtu = nd6_get_destination_mtu(dest, netif);
+  const u16_t nfb = (u16_t)((mtu - (IP6_HLEN + IP6_FRAG_HLEN)) & IP6_FRAG_OFFSET_MASK);
+  u16_t fragment_offset = 0;
+  u16_t last;
+  u16_t poff = IP6_HLEN;
+
+  identification++;
+
+  original_ip6hdr = (struct ip6_hdr *)p->payload;
+
+  /* @todo we assume there are no options in the unfragmentable part (IPv6 header). */
+  LWIP_ASSERT("p->tot_len >= IP6_HLEN", p->tot_len >= IP6_HLEN);
+  left = (u16_t)(p->tot_len - IP6_HLEN);
+
+  while (left) {
+    last = (left <= nfb);
+
+    /* Fill this fragment */
+    cop = last ? left : nfb;
+
+#if LWIP_NETIF_TX_SINGLE_PBUF
+    rambuf = pbuf_alloc(PBUF_IP, cop + IP6_FRAG_HLEN, PBUF_RAM);
+    if (rambuf == NULL) {
+      IP6_FRAG_STATS_INC(ip6_frag.memerr);
+      return ERR_MEM;
+    }
+    LWIP_ASSERT("this needs a pbuf in one piece!",
+      (rambuf->len == rambuf->tot_len) && (rambuf->next == NULL));
+    poff += pbuf_copy_partial(p, (u8_t*)rambuf->payload + IP6_FRAG_HLEN, cop, poff);
+    /* make room for the IP header */
+    if (pbuf_add_header(rambuf, IP6_HLEN)) {
+      pbuf_free(rambuf);
+      IP6_FRAG_STATS_INC(ip6_frag.memerr);
+      return ERR_MEM;
+    }
+    /* fill in the IP header */
+    SMEMCPY(rambuf->payload, original_ip6hdr, IP6_HLEN);
+    ip6hdr = (struct ip6_hdr *)rambuf->payload;
+    frag_hdr = (struct ip6_frag_hdr *)((u8_t*)rambuf->payload + IP6_HLEN);
+#else
+    /* When not using a static buffer, create a chain of pbufs.
+     * The first will be a PBUF_RAM holding the link, IPv6, and Fragment header.
+     * The rest will be PBUF_REFs mirroring the pbuf chain to be fragged,
+     * but limited to the size of an mtu.
+     */
+    rambuf = pbuf_alloc(PBUF_LINK, IP6_HLEN + IP6_FRAG_HLEN, PBUF_RAM);
+    if (rambuf == NULL) {
+      IP6_FRAG_STATS_INC(ip6_frag.memerr);
+      return ERR_MEM;
+    }
+    LWIP_ASSERT("this needs a pbuf in one piece!",
+                (rambuf->len >= (IP6_HLEN)));
+    SMEMCPY(rambuf->payload, original_ip6hdr, IP6_HLEN);
+    ip6hdr = (struct ip6_hdr *)rambuf->payload;
+    frag_hdr = (struct ip6_frag_hdr *)((u8_t*)rambuf->payload + IP6_HLEN);
+
+    /* Can just adjust p directly for needed offset. */
+    p->payload = (u8_t *)p->payload + poff;
+    p->len = (u16_t)(p->len - poff);
+    p->tot_len = (u16_t)(p->tot_len - poff);
+
+    left_to_copy = cop;
+    while (left_to_copy) {
+      struct pbuf_custom_ref *pcr;
+      newpbuflen = (left_to_copy < p->len) ? left_to_copy : p->len;
+      /* Is this pbuf already empty? */
+      if (!newpbuflen) {
+        p = p->next;
+        continue;
+      }
+      pcr = ip6_frag_alloc_pbuf_custom_ref();
+      if (pcr == NULL) {
+        pbuf_free(rambuf);
+        IP6_FRAG_STATS_INC(ip6_frag.memerr);
+        return ERR_MEM;
+      }
+      /* Mirror this pbuf, although we might not need all of it. */
+      newpbuf = pbuf_alloced_custom(PBUF_RAW, newpbuflen, PBUF_REF, &pcr->pc, p->payload, newpbuflen);
+      if (newpbuf == NULL) {
+        ip6_frag_free_pbuf_custom_ref(pcr);
+        pbuf_free(rambuf);
+        IP6_FRAG_STATS_INC(ip6_frag.memerr);
+        return ERR_MEM;
+      }
+      pbuf_ref(p);
+      pcr->original = p;
+      pcr->pc.custom_free_function = ip6_frag_free_pbuf_custom;
+
+      /* Add it to end of rambuf's chain, but using pbuf_cat, not pbuf_chain
+       * so that it is removed when pbuf_dechain is later called on rambuf.
+       */
+      pbuf_cat(rambuf, newpbuf);
+      left_to_copy = (u16_t)(left_to_copy - newpbuflen);
+      if (left_to_copy) {
+        p = p->next;
+      }
+    }
+    poff = newpbuflen;
+#endif /* LWIP_NETIF_TX_SINGLE_PBUF */
+
+    /* Set headers */
+    frag_hdr->_nexth = original_ip6hdr->_nexth;
+    frag_hdr->reserved = 0;
+    frag_hdr->_fragment_offset = lwip_htons((u16_t)((fragment_offset & IP6_FRAG_OFFSET_MASK) | (last ? 0 : IP6_FRAG_MORE_FLAG)));
+    frag_hdr->_identification = lwip_htonl(identification);
+
+    IP6H_NEXTH_SET(ip6hdr, IP6_NEXTH_FRAGMENT);
+    IP6H_PLEN_SET(ip6hdr, (u16_t)(cop + IP6_FRAG_HLEN));
+
+    /* No need for separate header pbuf - we allowed room for it in rambuf
+     * when allocated.
+     */
+    IP6_FRAG_STATS_INC(ip6_frag.xmit);
+    netif->output_ip6(netif, rambuf, dest);
+
+    /* Unfortunately we can't reuse rambuf - the hardware may still be
+     * using the buffer. Instead we free it (and the ensuing chain) and
+     * recreate it next time round the loop. If we're lucky the hardware
+     * will have already sent the packet, the free will really free, and
+     * there will be zero memory penalty.
+     */
+
+    pbuf_free(rambuf);
+    left = (u16_t)(left - cop);
+    fragment_offset = (u16_t)(fragment_offset + cop);
+  }
+  return ERR_OK;
+}
+
+#endif /* LWIP_IPV6 && LWIP_IPV6_FRAG */

Drivers/LwIP/src/core/ipv6/mld6.c

@@ -0,0 +1,626 @@
+/**
+ * @file
+ * Multicast listener discovery
+ *
+ * @defgroup mld6 MLD6
+ * @ingroup ip6
+ * Multicast listener discovery for IPv6. Aims to be compliant with RFC 2710.
+ * No support for MLDv2.<br>
+ * Note: The allnodes (ff01::1, ff02::1) group is assumed be received by your
+ * netif since it must always be received for correct IPv6 operation (e.g. SLAAC).
+ * Ensure the netif filters are configured accordingly!<br>
+ * The netif flags also need NETIF_FLAG_MLD6 flag set to enable MLD6 on a
+ * netif ("netif->flags |= NETIF_FLAG_MLD6;").<br>
+ * To be called from TCPIP thread.
+ */
+
+/*
+ * Copyright (c) 2010 Inico Technologies Ltd.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Ivan Delamer <delamer@inicotech.com>
+ *
+ *
+ * Please coordinate changes and requests with Ivan Delamer
+ * <delamer@inicotech.com>
+ */
+
+/* Based on igmp.c implementation of igmp v2 protocol */
+
+#include "lwip/opt.h"
+
+#if LWIP_IPV6 && LWIP_IPV6_MLD  /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/mld6.h"
+#include "lwip/prot/mld6.h"
+#include "lwip/icmp6.h"
+#include "lwip/ip6.h"
+#include "lwip/ip6_addr.h"
+#include "lwip/ip.h"
+#include "lwip/inet_chksum.h"
+#include "lwip/pbuf.h"
+#include "lwip/netif.h"
+#include "lwip/memp.h"
+#include "lwip/stats.h"
+
+#include <string.h>
+
+
+/*
+ * MLD constants
+ */
+#define MLD6_HL                           1
+#define MLD6_JOIN_DELAYING_MEMBER_TMR_MS  (500)
+
+#define MLD6_GROUP_NON_MEMBER             0
+#define MLD6_GROUP_DELAYING_MEMBER        1
+#define MLD6_GROUP_IDLE_MEMBER            2
+
+/* Forward declarations. */
+static struct mld_group *mld6_new_group(struct netif *ifp, const ip6_addr_t *addr);
+static err_t mld6_remove_group(struct netif *netif, struct mld_group *group);
+static void mld6_delayed_report(struct mld_group *group, u16_t maxresp);
+static void mld6_send(struct netif *netif, struct mld_group *group, u8_t type);
+
+
+/**
+ * Stop MLD processing on interface
+ *
+ * @param netif network interface on which stop MLD processing
+ */
+err_t
+mld6_stop(struct netif *netif)
+{
+  struct mld_group *group = netif_mld6_data(netif);
+
+  netif_set_client_data(netif, LWIP_NETIF_CLIENT_DATA_INDEX_MLD6, NULL);
+
+  while (group != NULL) {
+    struct mld_group *next = group->next; /* avoid use-after-free below */
+
+    /* disable the group at the MAC level */
+    if (netif->mld_mac_filter != NULL) {
+      netif->mld_mac_filter(netif, &(group->group_address), NETIF_DEL_MAC_FILTER);
+    }
+
+    /* free group */
+    memp_free(MEMP_MLD6_GROUP, group);
+
+    /* move to "next" */
+    group = next;
+  }
+  return ERR_OK;
+}
+
+/**
+ * Report MLD memberships for this interface
+ *
+ * @param netif network interface on which report MLD memberships
+ */
+void
+mld6_report_groups(struct netif *netif)
+{
+  struct mld_group *group = netif_mld6_data(netif);
+
+  while (group != NULL) {
+    mld6_delayed_report(group, MLD6_JOIN_DELAYING_MEMBER_TMR_MS);
+    group = group->next;
+  }
+}
+
+/**
+ * Search for a group that is joined on a netif
+ *
+ * @param ifp the network interface for which to look
+ * @param addr the group ipv6 address to search for
+ * @return a struct mld_group* if the group has been found,
+ *         NULL if the group wasn't found.
+ */
+struct mld_group *
+mld6_lookfor_group(struct netif *ifp, const ip6_addr_t *addr)
+{
+  struct mld_group *group = netif_mld6_data(ifp);
+
+  while (group != NULL) {
+    if (ip6_addr_eq(&(group->group_address), addr)) {
+      return group;
+    }
+    group = group->next;
+  }
+
+  return NULL;
+}
+
+
+/**
+ * create a new group
+ *
+ * @param ifp the network interface for which to create
+ * @param addr the new group ipv6
+ * @return a struct mld_group*,
+ *         NULL on memory error.
+ */
+static struct mld_group *
+mld6_new_group(struct netif *ifp, const ip6_addr_t *addr)
+{
+  struct mld_group *group;
+
+  group = (struct mld_group *)memp_malloc(MEMP_MLD6_GROUP);
+  if (group != NULL) {
+    ip6_addr_set(&(group->group_address), addr);
+    group->timer              = 0; /* Not running */
+    group->group_state        = MLD6_GROUP_IDLE_MEMBER;
+    group->last_reporter_flag = 0;
+    group->use                = 0;
+    group->next               = netif_mld6_data(ifp);
+
+    netif_set_client_data(ifp, LWIP_NETIF_CLIENT_DATA_INDEX_MLD6, group);
+  }
+
+  return group;
+}
+
+/**
+ * Remove a group from the mld_group_list, but do not free it yet
+ *
+ * @param group the group to remove
+ * @return ERR_OK if group was removed from the list, an err_t otherwise
+ */
+static err_t
+mld6_remove_group(struct netif *netif, struct mld_group *group)
+{
+  err_t err = ERR_OK;
+
+  /* Is it the first group? */
+  if (netif_mld6_data(netif) == group) {
+    netif_set_client_data(netif, LWIP_NETIF_CLIENT_DATA_INDEX_MLD6, group->next);
+  } else {
+    /* look for group further down the list */
+    struct mld_group *tmpGroup;
+    for (tmpGroup = netif_mld6_data(netif); tmpGroup != NULL; tmpGroup = tmpGroup->next) {
+      if (tmpGroup->next == group) {
+        tmpGroup->next = group->next;
+        break;
+      }
+    }
+    /* Group not find group */
+    if (tmpGroup == NULL) {
+      err = ERR_ARG;
+    }
+  }
+
+  return err;
+}
+
+
+/**
+ * Process an input MLD message. Called by icmp6_input.
+ *
+ * @param p the mld packet, p->payload pointing to the icmpv6 header
+ * @param inp the netif on which this packet was received
+ */
+void
+mld6_input(struct pbuf *p, struct netif *inp)
+{
+  struct mld_header *mld_hdr;
+  struct mld_group *group;
+
+  MLD6_STATS_INC(mld6.recv);
+
+  /* Check that mld header fits in packet. */
+  if (p->len < sizeof(struct mld_header)) {
+    /* @todo debug message */
+    pbuf_free(p);
+    MLD6_STATS_INC(mld6.lenerr);
+    MLD6_STATS_INC(mld6.drop);
+    return;
+  }
+
+  mld_hdr = (struct mld_header *)p->payload;
+
+  switch (mld_hdr->type) {
+  case ICMP6_TYPE_MLQ: /* Multicast listener query. */
+    /* Is it a general query? */
+    if (ip6_addr_isallnodes_linklocal(ip6_current_dest_addr()) &&
+        ip6_addr_isany(&(mld_hdr->multicast_address))) {
+      MLD6_STATS_INC(mld6.rx_general);
+      /* Report all groups, except all nodes group, and if-local groups. */
+      group = netif_mld6_data(inp);
+      while (group != NULL) {
+        if ((!(ip6_addr_ismulticast_iflocal(&(group->group_address)))) &&
+            (!(ip6_addr_isallnodes_linklocal(&(group->group_address))))) {
+          mld6_delayed_report(group, lwip_ntohs(mld_hdr->max_resp_delay));
+        }
+        group = group->next;
+      }
+    } else {
+      /* Have we joined this group?
+       * We use IP6 destination address to have a memory aligned copy.
+       * mld_hdr->multicast_address should be the same. */
+      MLD6_STATS_INC(mld6.rx_group);
+      group = mld6_lookfor_group(inp, ip6_current_dest_addr());
+      if (group != NULL) {
+        /* Schedule a report. */
+        mld6_delayed_report(group, lwip_ntohs(mld_hdr->max_resp_delay));
+      }
+    }
+    break; /* ICMP6_TYPE_MLQ */
+  case ICMP6_TYPE_MLR: /* Multicast listener report. */
+    /* Have we joined this group?
+     * We use IP6 destination address to have a memory aligned copy.
+     * mld_hdr->multicast_address should be the same. */
+    MLD6_STATS_INC(mld6.rx_report);
+    group = mld6_lookfor_group(inp, ip6_current_dest_addr());
+    if (group != NULL) {
+      /* If we are waiting to report, cancel it. */
+      if (group->group_state == MLD6_GROUP_DELAYING_MEMBER) {
+        group->timer = 0; /* stopped */
+        group->group_state = MLD6_GROUP_IDLE_MEMBER;
+        group->last_reporter_flag = 0;
+      }
+    }
+    break; /* ICMP6_TYPE_MLR */
+  case ICMP6_TYPE_MLD: /* Multicast listener done. */
+    /* Do nothing, router will query us. */
+    break; /* ICMP6_TYPE_MLD */
+  default:
+    MLD6_STATS_INC(mld6.proterr);
+    MLD6_STATS_INC(mld6.drop);
+    break;
+  }
+
+  pbuf_free(p);
+}
+
+/**
+ * @ingroup mld6
+ * Join a group on one or all network interfaces.
+ *
+ * If the group is to be joined on all interfaces, the given group address must
+ * not have a zone set (i.e., it must have its zone index set to IP6_NO_ZONE).
+ * If the group is to be joined on one particular interface, the given group
+ * address may or may not have a zone set.
+ *
+ * @param srcaddr ipv6 address (zoned) of the network interface which should
+ *                join a new group. If IP6_ADDR_ANY6, join on all netifs
+ * @param groupaddr the ipv6 address of the group to join (possibly but not
+ *                  necessarily zoned)
+ * @return ERR_OK if group was joined on the netif(s), an err_t otherwise
+ */
+err_t
+mld6_joingroup(const ip6_addr_t *srcaddr, const ip6_addr_t *groupaddr)
+{
+  err_t         err = ERR_VAL; /* no matching interface */
+  struct netif *netif;
+
+  LWIP_ASSERT_CORE_LOCKED();
+
+  /* loop through netif's */
+  NETIF_FOREACH(netif) {
+    /* Should we join this interface ? */
+    if (ip6_addr_isany(srcaddr) ||
+        netif_get_ip6_addr_match(netif, srcaddr) >= 0) {
+      err = mld6_joingroup_netif(netif, groupaddr);
+      if (err != ERR_OK) {
+        return err;
+      }
+    }
+  }
+
+  return err;
+}
+
+/**
+ * @ingroup mld6
+ * Join a group on a network interface.
+ *
+ * @param netif the network interface which should join a new group.
+ * @param groupaddr the ipv6 address of the group to join (possibly but not
+ *                  necessarily zoned)
+ * @return ERR_OK if group was joined on the netif, an err_t otherwise
+ */
+err_t
+mld6_joingroup_netif(struct netif *netif, const ip6_addr_t *groupaddr)
+{
+  struct mld_group *group;
+#if LWIP_IPV6_SCOPES
+  ip6_addr_t ip6addr;
+
+  /* If the address has a particular scope but no zone set, use the netif to
+   * set one now. Within the mld6 module, all addresses are properly zoned. */
+  if (ip6_addr_lacks_zone(groupaddr, IP6_MULTICAST)) {
+    ip6_addr_set(&ip6addr, groupaddr);
+    ip6_addr_assign_zone(&ip6addr, IP6_MULTICAST, netif);
+    groupaddr = &ip6addr;
+  }
+  IP6_ADDR_ZONECHECK_NETIF(groupaddr, netif);
+#endif /* LWIP_IPV6_SCOPES */
+
+  LWIP_ASSERT_CORE_LOCKED();
+
+  /* find group or create a new one if not found */
+  group = mld6_lookfor_group(netif, groupaddr);
+
+  if (group == NULL) {
+    /* Joining a new group. Create a new group entry. */
+    group = mld6_new_group(netif, groupaddr);
+    if (group == NULL) {
+      return ERR_MEM;
+    }
+
+    /* Activate this address on the MAC layer. */
+    if (netif->mld_mac_filter != NULL) {
+      netif->mld_mac_filter(netif, groupaddr, NETIF_ADD_MAC_FILTER);
+    }
+
+    /* Report our membership. */
+    MLD6_STATS_INC(mld6.tx_report);
+    mld6_send(netif, group, ICMP6_TYPE_MLR);
+    mld6_delayed_report(group, MLD6_JOIN_DELAYING_MEMBER_TMR_MS);
+  }
+
+  /* Increment group use */
+  group->use++;
+  return ERR_OK;
+}
+
+/**
+ * @ingroup mld6
+ * Leave a group on a network interface.
+ *
+ * Zoning of address follows the same rules as @ref mld6_joingroup.
+ *
+ * @param srcaddr ipv6 address (zoned) of the network interface which should
+ *                leave the group. If IP6_ADDR_ANY6, leave on all netifs
+ * @param groupaddr the ipv6 address of the group to leave (possibly, but not
+ *                  necessarily zoned)
+ * @return ERR_OK if group was left on the netif(s), an err_t otherwise
+ */
+err_t
+mld6_leavegroup(const ip6_addr_t *srcaddr, const ip6_addr_t *groupaddr)
+{
+  err_t         err = ERR_VAL; /* no matching interface */
+  struct netif *netif;
+
+  LWIP_ASSERT_CORE_LOCKED();
+
+  /* loop through netif's */
+  NETIF_FOREACH(netif) {
+    /* Should we leave this interface ? */
+    if (ip6_addr_isany(srcaddr) ||
+        netif_get_ip6_addr_match(netif, srcaddr) >= 0) {
+      err_t res = mld6_leavegroup_netif(netif, groupaddr);
+      if (err != ERR_OK) {
+        /* Store this result if we have not yet gotten a success */
+        err = res;
+      }
+    }
+  }
+
+  return err;
+}
+
+/**
+ * @ingroup mld6
+ * Leave a group on a network interface.
+ *
+ * @param netif the network interface which should leave the group.
+ * @param groupaddr the ipv6 address of the group to leave (possibly, but not
+ *                  necessarily zoned)
+ * @return ERR_OK if group was left on the netif, an err_t otherwise
+ */
+err_t
+mld6_leavegroup_netif(struct netif *netif, const ip6_addr_t *groupaddr)
+{
+  struct mld_group *group;
+#if LWIP_IPV6_SCOPES
+  ip6_addr_t ip6addr;
+
+  if (ip6_addr_lacks_zone(groupaddr, IP6_MULTICAST)) {
+    ip6_addr_set(&ip6addr, groupaddr);
+    ip6_addr_assign_zone(&ip6addr, IP6_MULTICAST, netif);
+    groupaddr = &ip6addr;
+  }
+  IP6_ADDR_ZONECHECK_NETIF(groupaddr, netif);
+#endif /* LWIP_IPV6_SCOPES */
+
+  LWIP_ASSERT_CORE_LOCKED();
+
+  /* find group */
+  group = mld6_lookfor_group(netif, groupaddr);
+
+  if (group != NULL) {
+    /* Leave if there is no other use of the group */
+    if (group->use <= 1) {
+      /* Remove the group from the list */
+      mld6_remove_group(netif, group);
+
+      /* If we are the last reporter for this group */
+      if (group->last_reporter_flag) {
+        MLD6_STATS_INC(mld6.tx_leave);
+        mld6_send(netif, group, ICMP6_TYPE_MLD);
+      }
+
+      /* Disable the group at the MAC level */
+      if (netif->mld_mac_filter != NULL) {
+        netif->mld_mac_filter(netif, groupaddr, NETIF_DEL_MAC_FILTER);
+      }
+
+      /* free group struct */
+      memp_free(MEMP_MLD6_GROUP, group);
+    } else {
+      /* Decrement group use */
+      group->use--;
+    }
+
+    /* Left group */
+    return ERR_OK;
+  }
+
+  /* Group not found */
+  return ERR_VAL;
+}
+
+
+/**
+ * Periodic timer for mld processing. Must be called every
+ * MLD6_TMR_INTERVAL milliseconds (100).
+ *
+ * When a delaying member expires, a membership report is sent.
+ */
+void
+mld6_tmr(void)
+{
+  struct netif *netif;
+
+  NETIF_FOREACH(netif) {
+    struct mld_group *group = netif_mld6_data(netif);
+
+    while (group != NULL) {
+      if (group->timer > 0) {
+        group->timer--;
+        if (group->timer == 0) {
+          /* If the state is MLD6_GROUP_DELAYING_MEMBER then we send a report for this group */
+          if (group->group_state == MLD6_GROUP_DELAYING_MEMBER) {
+            MLD6_STATS_INC(mld6.tx_report);
+            mld6_send(netif, group, ICMP6_TYPE_MLR);
+            group->group_state = MLD6_GROUP_IDLE_MEMBER;
+          }
+        }
+      }
+      group = group->next;
+    }
+  }
+}
+
+/**
+ * Schedule a delayed membership report for a group
+ *
+ * @param group the mld_group for which "delaying" membership report
+ *              should be sent
+ * @param maxresp_in the max resp delay provided in the query
+ */
+static void
+mld6_delayed_report(struct mld_group *group, u16_t maxresp_in)
+{
+  /* Convert maxresp from milliseconds to tmr ticks */
+  u16_t maxresp = maxresp_in / MLD6_TMR_INTERVAL;
+  if (maxresp == 0) {
+    maxresp = 1;
+  }
+
+#ifdef LWIP_RAND
+  /* Randomize maxresp. (if LWIP_RAND is supported) */
+  maxresp = (u16_t)(LWIP_RAND() % maxresp);
+  if (maxresp == 0) {
+    maxresp = 1;
+  }
+#endif /* LWIP_RAND */
+
+  /* Apply timer value if no report has been scheduled already. */
+  if ((group->group_state == MLD6_GROUP_IDLE_MEMBER) ||
+     ((group->group_state == MLD6_GROUP_DELAYING_MEMBER) &&
+      ((group->timer == 0) || (maxresp < group->timer)))) {
+    group->timer = maxresp;
+    group->group_state = MLD6_GROUP_DELAYING_MEMBER;
+  }
+}
+
+/**
+ * Send a MLD message (report or done).
+ *
+ * An IPv6 hop-by-hop options header with a router alert option
+ * is prepended.
+ *
+ * @param group the group to report or quit
+ * @param type ICMP6_TYPE_MLR (report) or ICMP6_TYPE_MLD (done)
+ */
+static void
+mld6_send(struct netif *netif, struct mld_group *group, u8_t type)
+{
+  struct mld_header *mld_hdr;
+  struct pbuf *p;
+  const ip6_addr_t *src_addr;
+
+  /* Allocate a packet. Size is MLD header + IPv6 Hop-by-hop options header. */
+  p = pbuf_alloc(PBUF_IP, sizeof(struct mld_header) + MLD6_HBH_HLEN, PBUF_RAM);
+  if (p == NULL) {
+    MLD6_STATS_INC(mld6.memerr);
+    return;
+  }
+
+  /* Move to make room for Hop-by-hop options header. */
+  if (pbuf_remove_header(p, MLD6_HBH_HLEN)) {
+    pbuf_free(p);
+    MLD6_STATS_INC(mld6.lenerr);
+    return;
+  }
+
+  /* Select our source address. */
+  if (!ip6_addr_isvalid(netif_ip6_addr_state(netif, 0))) {
+    /* This is a special case, when we are performing duplicate address detection.
+     * We must join the multicast group, but we don't have a valid address yet. */
+    src_addr = IP6_ADDR_ANY6;
+  } else {
+    /* Use link-local address as source address. */
+    src_addr = netif_ip6_addr(netif, 0);
+  }
+
+  /* MLD message header pointer. */
+  mld_hdr = (struct mld_header *)p->payload;
+
+  /* Set fields. */
+  mld_hdr->type = type;
+  mld_hdr->code = 0;
+  mld_hdr->chksum = 0;
+  mld_hdr->max_resp_delay = 0;
+  mld_hdr->reserved = 0;
+  ip6_addr_copy_to_packed(mld_hdr->multicast_address, group->group_address);
+
+#if CHECKSUM_GEN_ICMP6
+  IF__NETIF_CHECKSUM_ENABLED(netif, NETIF_CHECKSUM_GEN_ICMP6) {
+    mld_hdr->chksum = ip6_chksum_pseudo(p, IP6_NEXTH_ICMP6, p->len,
+      src_addr, &(group->group_address));
+  }
+#endif /* CHECKSUM_GEN_ICMP6 */
+
+  /* Add hop-by-hop headers options: router alert with MLD value. */
+  ip6_options_add_hbh_ra(p, IP6_NEXTH_ICMP6, IP6_ROUTER_ALERT_VALUE_MLD);
+
+  if (type == ICMP6_TYPE_MLR) {
+    /* Remember we were the last to report */
+    group->last_reporter_flag = 1;
+  }
+
+  /* Send the packet out. */
+  MLD6_STATS_INC(mld6.xmit);
+  ip6_output_if(p, (ip6_addr_isany(src_addr)) ? NULL : src_addr, &(group->group_address),
+      MLD6_HL, 0, IP6_NEXTH_HOPBYHOP, netif);
+  pbuf_free(p);
+}
+
+#endif /* LWIP_IPV6 */

Drivers/LwIP/src/core/memp.c

@@ -0,0 +1,447 @@
+/**
+ * @file
+ * Dynamic pool memory manager
+ *
+ * lwIP has dedicated pools for many structures (netconn, protocol control blocks,
+ * packet buffers, ...). All these pools are managed here.
+ *
+ * @defgroup mempool Memory pools
+ * @ingroup infrastructure
+ * Custom memory pools
+
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+
+#include "lwip/opt.h"
+
+#include "lwip/memp.h"
+#include "lwip/sys.h"
+#include "lwip/stats.h"
+
+#include <string.h>
+
+/* Make sure we include everything we need for size calculation required by memp_std.h */
+#include "lwip/pbuf.h"
+#include "lwip/raw.h"
+#include "lwip/udp.h"
+#include "lwip/tcp.h"
+#include "lwip/priv/tcp_priv.h"
+#include "lwip/altcp.h"
+#include "lwip/ip4_frag.h"
+#include "lwip/netbuf.h"
+#include "lwip/api.h"
+#include "lwip/priv/tcpip_priv.h"
+#include "lwip/priv/api_msg.h"
+#include "lwip/priv/sockets_priv.h"
+#include "lwip/etharp.h"
+#include "lwip/igmp.h"
+#include "lwip/timeouts.h"
+/* needed by default MEMP_NUM_SYS_TIMEOUT */
+#include "netif/ppp/ppp_opts.h"
+#include "lwip/netdb.h"
+#include "lwip/dns.h"
+#include "lwip/priv/nd6_priv.h"
+#include "lwip/ip6_frag.h"
+#include "lwip/mld6.h"
+
+#define LWIP_MEMPOOL(name,num,size,desc) LWIP_MEMPOOL_DECLARE(name,num,size,desc)
+#include "lwip/priv/memp_std.h"
+
+const struct memp_desc *const memp_pools[MEMP_MAX] = {
+#define LWIP_MEMPOOL(name,num,size,desc) &memp_ ## name,
+#include "lwip/priv/memp_std.h"
+};
+
+#ifdef LWIP_HOOK_FILENAME
+#include LWIP_HOOK_FILENAME
+#endif
+
+#if MEMP_MEM_MALLOC && MEMP_OVERFLOW_CHECK >= 2
+#undef MEMP_OVERFLOW_CHECK
+/* MEMP_OVERFLOW_CHECK >= 2 does not work with MEMP_MEM_MALLOC, use 1 instead */
+#define MEMP_OVERFLOW_CHECK 1
+#endif
+
+#if MEMP_SANITY_CHECK && !MEMP_MEM_MALLOC
+/**
+ * Check that memp-lists don't form a circle, using "Floyd's cycle-finding algorithm".
+ */
+static int
+memp_sanity(const struct memp_desc *desc)
+{
+  struct memp *t, *h;
+
+  t = *desc->tab;
+  if (t != NULL) {
+    for (h = t->next; (t != NULL) && (h != NULL); t = t->next,
+         h = ((h->next != NULL) ? h->next->next : NULL)) {
+      if (t == h) {
+        return 0;
+      }
+    }
+  }
+
+  return 1;
+}
+#endif /* MEMP_SANITY_CHECK && !MEMP_MEM_MALLOC */
+
+#if MEMP_OVERFLOW_CHECK
+/**
+ * Check if a memp element was victim of an overflow or underflow
+ * (e.g. the restricted area after/before it has been altered)
+ *
+ * @param p the memp element to check
+ * @param desc the pool p comes from
+ */
+static void
+memp_overflow_check_element(struct memp *p, const struct memp_desc *desc)
+{
+  mem_overflow_check_raw((u8_t *)p + MEMP_SIZE, desc->size, "pool ", desc->desc);
+}
+
+/**
+ * Initialize the restricted area of on memp element.
+ */
+static void
+memp_overflow_init_element(struct memp *p, const struct memp_desc *desc)
+{
+  mem_overflow_init_raw((u8_t *)p + MEMP_SIZE, desc->size);
+}
+
+#if MEMP_OVERFLOW_CHECK >= 2
+/**
+ * Do an overflow check for all elements in every pool.
+ *
+ * @see memp_overflow_check_element for a description of the check
+ */
+static void
+memp_overflow_check_all(void)
+{
+  u16_t i, j;
+  struct memp *p;
+  SYS_ARCH_DECL_PROTECT(old_level);
+  SYS_ARCH_PROTECT(old_level);
+
+  for (i = 0; i < MEMP_MAX; ++i) {
+    p = (struct memp *)LWIP_MEM_ALIGN(memp_pools[i]->base);
+    for (j = 0; j < memp_pools[i]->num; ++j) {
+      memp_overflow_check_element(p, memp_pools[i]);
+      p = LWIP_ALIGNMENT_CAST(struct memp *, ((u8_t *)p + MEMP_SIZE + memp_pools[i]->size + MEM_SANITY_REGION_AFTER_ALIGNED));
+    }
+  }
+  SYS_ARCH_UNPROTECT(old_level);
+}
+#endif /* MEMP_OVERFLOW_CHECK >= 2 */
+#endif /* MEMP_OVERFLOW_CHECK */
+
+/**
+ * Initialize custom memory pool.
+ * Related functions: memp_malloc_pool, memp_free_pool
+ *
+ * @param desc pool to initialize
+ */
+void
+memp_init_pool(const struct memp_desc *desc)
+{
+#if MEMP_MEM_MALLOC
+  LWIP_UNUSED_ARG(desc);
+#else
+  int i;
+  struct memp *memp;
+
+  *desc->tab = NULL;
+  memp = (struct memp *)LWIP_MEM_ALIGN(desc->base);
+#if MEMP_MEM_INIT
+  /* force memset on pool memory */
+  memset(memp, 0, (size_t)desc->num * (MEMP_SIZE + desc->size
+#if MEMP_OVERFLOW_CHECK
+                                       + MEM_SANITY_REGION_AFTER_ALIGNED
+#endif
+                                      ));
+#endif
+  /* create a linked list of memp elements */
+  for (i = 0; i < desc->num; ++i) {
+    memp->next = *desc->tab;
+    *desc->tab = memp;
+#if MEMP_OVERFLOW_CHECK
+    memp_overflow_init_element(memp, desc);
+#endif /* MEMP_OVERFLOW_CHECK */
+    /* cast through void* to get rid of alignment warnings */
+    memp = (struct memp *)(void *)((u8_t *)memp + MEMP_SIZE + desc->size
+#if MEMP_OVERFLOW_CHECK
+                                   + MEM_SANITY_REGION_AFTER_ALIGNED
+#endif
+                                  );
+  }
+#if MEMP_STATS
+  desc->stats->avail = desc->num;
+#endif /* MEMP_STATS */
+#endif /* !MEMP_MEM_MALLOC */
+
+#if MEMP_STATS && (defined(LWIP_DEBUG) || LWIP_STATS_DISPLAY)
+  desc->stats->name  = desc->desc;
+#endif /* MEMP_STATS && (defined(LWIP_DEBUG) || LWIP_STATS_DISPLAY) */
+}
+
+/**
+ * Initializes lwIP built-in pools.
+ * Related functions: memp_malloc, memp_free
+ *
+ * Carves out memp_memory into linked lists for each pool-type.
+ */
+void
+memp_init(void)
+{
+  u16_t i;
+
+  /* for every pool: */
+  for (i = 0; i < LWIP_ARRAYSIZE(memp_pools); i++) {
+    memp_init_pool(memp_pools[i]);
+
+#if LWIP_STATS && MEMP_STATS
+    lwip_stats.memp[i] = memp_pools[i]->stats;
+#endif
+  }
+
+#if MEMP_OVERFLOW_CHECK >= 2
+  /* check everything a first time to see if it worked */
+  memp_overflow_check_all();
+#endif /* MEMP_OVERFLOW_CHECK >= 2 */
+}
+
+static void *
+#if !MEMP_OVERFLOW_CHECK
+do_memp_malloc_pool(const struct memp_desc *desc)
+#else
+do_memp_malloc_pool_fn(const struct memp_desc *desc, const char *file, const int line)
+#endif
+{
+  struct memp *memp;
+  SYS_ARCH_DECL_PROTECT(old_level);
+
+#if MEMP_MEM_MALLOC
+  memp = (struct memp *)mem_malloc(MEMP_SIZE + MEMP_ALIGN_SIZE(desc->size));
+  SYS_ARCH_PROTECT(old_level);
+#else /* MEMP_MEM_MALLOC */
+  SYS_ARCH_PROTECT(old_level);
+
+  memp = *desc->tab;
+#endif /* MEMP_MEM_MALLOC */
+
+  if (memp != NULL) {
+#if !MEMP_MEM_MALLOC
+#if MEMP_OVERFLOW_CHECK == 1
+    memp_overflow_check_element(memp, desc);
+#endif /* MEMP_OVERFLOW_CHECK */
+
+    *desc->tab = memp->next;
+#if MEMP_OVERFLOW_CHECK
+    memp->next = NULL;
+#endif /* MEMP_OVERFLOW_CHECK */
+#endif /* !MEMP_MEM_MALLOC */
+#if MEMP_OVERFLOW_CHECK
+    memp->file = file;
+    memp->line = line;
+#if MEMP_MEM_MALLOC
+    memp_overflow_init_element(memp, desc);
+#endif /* MEMP_MEM_MALLOC */
+#endif /* MEMP_OVERFLOW_CHECK */
+    LWIP_ASSERT("memp_malloc: memp properly aligned",
+                ((mem_ptr_t)memp % MEM_ALIGNMENT) == 0);
+#if MEMP_STATS
+    desc->stats->used++;
+    if (desc->stats->used > desc->stats->max) {
+      desc->stats->max = desc->stats->used;
+    }
+#endif
+    SYS_ARCH_UNPROTECT(old_level);
+    /* cast through u8_t* to get rid of alignment warnings */
+    return ((u8_t *)memp + MEMP_SIZE);
+  } else {
+#if MEMP_STATS
+    desc->stats->err++;
+#endif
+    SYS_ARCH_UNPROTECT(old_level);
+    LWIP_DEBUGF(MEMP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("memp_malloc: out of memory in pool %s\n", desc->desc));
+  }
+
+  return NULL;
+}
+
+/**
+ * Get an element from a custom pool.
+ *
+ * @param desc the pool to get an element from
+ *
+ * @return a pointer to the allocated memory or a NULL pointer on error
+ */
+void *
+#if !MEMP_OVERFLOW_CHECK
+memp_malloc_pool(const struct memp_desc *desc)
+#else
+memp_malloc_pool_fn(const struct memp_desc *desc, const char *file, const int line)
+#endif
+{
+  LWIP_ASSERT("invalid pool desc", desc != NULL);
+  if (desc == NULL) {
+    return NULL;
+  }
+
+#if !MEMP_OVERFLOW_CHECK
+  return do_memp_malloc_pool(desc);
+#else
+  return do_memp_malloc_pool_fn(desc, file, line);
+#endif
+}
+
+/**
+ * Get an element from a specific pool.
+ *
+ * @param type the pool to get an element from
+ *
+ * @return a pointer to the allocated memory or a NULL pointer on error
+ */
+void *
+#if !MEMP_OVERFLOW_CHECK
+memp_malloc(memp_t type)
+#else
+memp_malloc_fn(memp_t type, const char *file, const int line)
+#endif
+{
+  void *memp;
+  LWIP_ERROR("memp_malloc: type < MEMP_MAX", (type < MEMP_MAX), return NULL;);
+
+#if MEMP_OVERFLOW_CHECK >= 2
+  memp_overflow_check_all();
+#endif /* MEMP_OVERFLOW_CHECK >= 2 */
+
+#if !MEMP_OVERFLOW_CHECK
+  memp = do_memp_malloc_pool(memp_pools[type]);
+#else
+  memp = do_memp_malloc_pool_fn(memp_pools[type], file, line);
+#endif
+
+  return memp;
+}
+
+static void
+do_memp_free_pool(const struct memp_desc *desc, void *mem)
+{
+  struct memp *memp;
+  SYS_ARCH_DECL_PROTECT(old_level);
+
+  LWIP_ASSERT("memp_free: mem properly aligned",
+              ((mem_ptr_t)mem % MEM_ALIGNMENT) == 0);
+
+  /* cast through void* to get rid of alignment warnings */
+  memp = (struct memp *)(void *)((u8_t *)mem - MEMP_SIZE);
+
+  SYS_ARCH_PROTECT(old_level);
+
+#if MEMP_OVERFLOW_CHECK == 1
+  memp_overflow_check_element(memp, desc);
+#endif /* MEMP_OVERFLOW_CHECK */
+
+#if MEMP_STATS
+  desc->stats->used--;
+#endif
+
+#if MEMP_MEM_MALLOC
+  LWIP_UNUSED_ARG(desc);
+  SYS_ARCH_UNPROTECT(old_level);
+  mem_free(memp);
+#else /* MEMP_MEM_MALLOC */
+  memp->next = *desc->tab;
+  *desc->tab = memp;
+
+#if MEMP_SANITY_CHECK
+  LWIP_ASSERT("memp sanity", memp_sanity(desc));
+#endif /* MEMP_SANITY_CHECK */
+
+  SYS_ARCH_UNPROTECT(old_level);
+#endif /* !MEMP_MEM_MALLOC */
+}
+
+/**
+ * Put a custom pool element back into its pool.
+ *
+ * @param desc the pool where to put mem
+ * @param mem the memp element to free
+ */
+void
+memp_free_pool(const struct memp_desc *desc, void *mem)
+{
+  LWIP_ASSERT("invalid pool desc", desc != NULL);
+  if ((desc == NULL) || (mem == NULL)) {
+    return;
+  }
+
+  do_memp_free_pool(desc, mem);
+}
+
+/**
+ * Put an element back into its pool.
+ *
+ * @param type the pool where to put mem
+ * @param mem the memp element to free
+ */
+void
+memp_free(memp_t type, void *mem)
+{
+#ifdef LWIP_HOOK_MEMP_AVAILABLE
+  struct memp *old_first;
+#endif
+
+  LWIP_ERROR("memp_free: type < MEMP_MAX", (type < MEMP_MAX), return;);
+
+  if (mem == NULL) {
+    return;
+  }
+
+#if MEMP_OVERFLOW_CHECK >= 2
+  memp_overflow_check_all();
+#endif /* MEMP_OVERFLOW_CHECK >= 2 */
+
+#ifdef LWIP_HOOK_MEMP_AVAILABLE
+  old_first = *memp_pools[type]->tab;
+#endif
+
+  do_memp_free_pool(memp_pools[type], mem);
+
+#ifdef LWIP_HOOK_MEMP_AVAILABLE
+  if (old_first == NULL) {
+    LWIP_HOOK_MEMP_AVAILABLE(type);
+  }
+#endif
+}

Drivers/LwIP/src/core/raw.c

@@ -0,0 +1,673 @@
+/**
+ * @file
+ * Implementation of raw protocol PCBs for low-level handling of
+ * different types of protocols besides (or overriding) those
+ * already available in lwIP.<br>
+ * See also @ref raw_raw
+ *
+ * @defgroup raw_raw RAW
+ * @ingroup callbackstyle_api
+ * Implementation of raw protocol PCBs for low-level handling of
+ * different types of protocols besides (or overriding) those
+ * already available in lwIP.<br>
+ * @see @ref api
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+
+#include "lwip/opt.h"
+
+#if LWIP_RAW /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/def.h"
+#include "lwip/memp.h"
+#include "lwip/ip_addr.h"
+#include "lwip/netif.h"
+#include "lwip/raw.h"
+#include "lwip/priv/raw_priv.h"
+#include "lwip/stats.h"
+#include "lwip/ip6.h"
+#include "lwip/ip6_addr.h"
+#include "lwip/inet_chksum.h"
+
+#include <string.h>
+
+/** The list of RAW PCBs */
+static struct raw_pcb *raw_pcbs;
+
+static u8_t
+raw_input_local_match(struct raw_pcb *pcb, u8_t broadcast)
+{
+  LWIP_UNUSED_ARG(broadcast); /* in IPv6 only case */
+
+  /* check if PCB is bound to specific netif */
+  if ((pcb->netif_idx != NETIF_NO_INDEX) &&
+      (pcb->netif_idx != netif_get_index(ip_data.current_input_netif))) {
+    return 0;
+  }
+
+#if LWIP_IPV4 && LWIP_IPV6
+  /* Dual-stack: PCBs listening to any IP type also listen to any IP address */
+  if (IP_IS_ANY_TYPE_VAL(pcb->local_ip)) {
+#if IP_SOF_BROADCAST_RECV
+    if ((broadcast != 0) && !ip_get_option(pcb, SOF_BROADCAST)) {
+      return 0;
+    }
+#endif /* IP_SOF_BROADCAST_RECV */
+    return 1;
+  }
+#endif /* LWIP_IPV4 && LWIP_IPV6 */
+
+  /* Only need to check PCB if incoming IP version matches PCB IP version */
+  if (IP_ADDR_PCB_VERSION_MATCH_EXACT(pcb, ip_current_dest_addr())) {
+#if LWIP_IPV4
+    /* Special case: IPv4 broadcast: receive all broadcasts
+     * Note: broadcast variable can only be 1 if it is an IPv4 broadcast */
+    if (broadcast != 0) {
+#if IP_SOF_BROADCAST_RECV
+      if (ip_get_option(pcb, SOF_BROADCAST))
+#endif /* IP_SOF_BROADCAST_RECV */
+      {
+        if (ip4_addr_isany(ip_2_ip4(&pcb->local_ip))) {
+          return 1;
+        }
+      }
+    } else
+#endif /* LWIP_IPV4 */
+      /* Handle IPv4 and IPv6: catch all or exact match */
+      if (ip_addr_isany(&pcb->local_ip) ||
+          ip_addr_eq(&pcb->local_ip, ip_current_dest_addr())) {
+        return 1;
+      }
+  }
+
+  return 0;
+}
+
+/**
+ * Determine if in incoming IP packet is covered by a RAW PCB
+ * and if so, pass it to a user-provided receive callback function.
+ *
+ * Given an incoming IP datagram (as a chain of pbufs) this function
+ * finds a corresponding RAW PCB and calls the corresponding receive
+ * callback function.
+ *
+ * @param p pbuf to be demultiplexed to a RAW PCB.
+ * @param inp network interface on which the datagram was received.
+ * @return - 1 if the packet has been eaten by a RAW PCB receive
+ *           callback function. The caller MAY NOT not reference the
+ *           packet any longer, and MAY NOT call pbuf_free().
+ * @return - 0 if packet is not eaten (pbuf is still referenced by the
+ *           caller).
+ *
+ */
+raw_input_state_t
+raw_input(struct pbuf *p, struct netif *inp)
+{
+  struct raw_pcb *pcb, *prev;
+  s16_t proto;
+  raw_input_state_t ret = RAW_INPUT_NONE;
+  u8_t broadcast = ip_addr_isbroadcast(ip_current_dest_addr(), ip_current_netif());
+
+  LWIP_UNUSED_ARG(inp);
+
+#if LWIP_IPV6
+#if LWIP_IPV4
+  if (IP_HDR_GET_VERSION(p->payload) == 6)
+#endif /* LWIP_IPV4 */
+  {
+    struct ip6_hdr *ip6hdr = (struct ip6_hdr *)p->payload;
+    proto = IP6H_NEXTH(ip6hdr);
+  }
+#if LWIP_IPV4
+  else
+#endif /* LWIP_IPV4 */
+#endif /* LWIP_IPV6 */
+#if LWIP_IPV4
+  {
+    proto = IPH_PROTO((struct ip_hdr *)p->payload);
+  }
+#endif /* LWIP_IPV4 */
+
+  prev = NULL;
+  pcb = raw_pcbs;
+  /* loop through all raw pcbs until the packet is eaten by one */
+  /* this allows multiple pcbs to match against the packet by design */
+  while (pcb != NULL) {
+    if ((pcb->protocol == proto) && raw_input_local_match(pcb, broadcast) &&
+        (((pcb->flags & RAW_FLAGS_CONNECTED) == 0) ||
+         ip_addr_eq(&pcb->remote_ip, ip_current_src_addr()))) {
+      /* receive callback function available? */
+      if (pcb->recv != NULL) {
+        u8_t eaten;
+#ifndef LWIP_NOASSERT
+        void *old_payload = p->payload;
+#endif
+        ret = RAW_INPUT_DELIVERED;
+        /* the receive callback function did not eat the packet? */
+        eaten = pcb->recv(pcb->recv_arg, pcb, p, ip_current_src_addr());
+        if (eaten != 0) {
+          /* receive function ate the packet */
+          p = NULL;
+          if (prev != NULL) {
+            /* move the pcb to the front of raw_pcbs so that is
+               found faster next time */
+            prev->next = pcb->next;
+            pcb->next = raw_pcbs;
+            raw_pcbs = pcb;
+          }
+          return RAW_INPUT_EATEN;
+        } else {
+          /* sanity-check that the receive callback did not alter the pbuf */
+          LWIP_ASSERT("raw pcb recv callback altered pbuf payload pointer without eating packet",
+                      p->payload == old_payload);
+        }
+      }
+      /* no receive callback function was set for this raw PCB */
+    }
+    /* drop the packet */
+    prev = pcb;
+    pcb = pcb->next;
+  }
+  return ret;
+}
+
+/**
+ * @ingroup raw_raw
+ * Bind a RAW PCB.
+ *
+ * @param pcb RAW PCB to be bound with a local address ipaddr.
+ * @param ipaddr local IP address to bind with. Use IP4_ADDR_ANY to
+ * bind to all local interfaces.
+ *
+ * @return lwIP error code.
+ * - ERR_OK. Successful. No error occurred.
+ * - ERR_USE. The specified IP address is already bound to by
+ * another RAW PCB.
+ *
+ * @see raw_disconnect()
+ */
+err_t
+raw_bind(struct raw_pcb *pcb, const ip_addr_t *ipaddr)
+{
+  LWIP_ASSERT_CORE_LOCKED();
+  if ((pcb == NULL) || (ipaddr == NULL)) {
+    return ERR_VAL;
+  }
+  ip_addr_set_ipaddr(&pcb->local_ip, ipaddr);
+#if LWIP_IPV6 && LWIP_IPV6_SCOPES
+  /* If the given IP address should have a zone but doesn't, assign one now.
+   * This is legacy support: scope-aware callers should always provide properly
+   * zoned source addresses. */
+  if (IP_IS_V6(&pcb->local_ip) &&
+      ip6_addr_lacks_zone(ip_2_ip6(&pcb->local_ip), IP6_UNKNOWN)) {
+    ip6_addr_select_zone(ip_2_ip6(&pcb->local_ip), ip_2_ip6(&pcb->local_ip));
+  }
+#endif /* LWIP_IPV6 && LWIP_IPV6_SCOPES */
+  return ERR_OK;
+}
+
+/**
+ * @ingroup raw_raw
+ * Bind an RAW PCB to a specific netif.
+ * After calling this function, all packets received via this PCB
+ * are guaranteed to have come in via the specified netif, and all
+ * outgoing packets will go out via the specified netif.
+ *
+ * @param pcb RAW PCB to be bound with netif.
+ * @param netif netif to bind to. Can be NULL.
+ *
+ * @see raw_disconnect()
+ */
+void
+raw_bind_netif(struct raw_pcb *pcb, const struct netif *netif)
+{
+  LWIP_ASSERT_CORE_LOCKED();
+  if (netif != NULL) {
+    pcb->netif_idx = netif_get_index(netif);
+  } else {
+    pcb->netif_idx = NETIF_NO_INDEX;
+  }
+}
+
+/**
+ * @ingroup raw_raw
+ * Connect an RAW PCB. This function is required by upper layers
+ * of lwip. Using the raw api you could use raw_sendto() instead
+ *
+ * This will associate the RAW PCB with the remote address.
+ *
+ * @param pcb RAW PCB to be connected with remote address ipaddr and port.
+ * @param ipaddr remote IP address to connect with.
+ *
+ * @return lwIP error code
+ *
+ * @see raw_disconnect() and raw_sendto()
+ */
+err_t
+raw_connect(struct raw_pcb *pcb, const ip_addr_t *ipaddr)
+{
+  LWIP_ASSERT_CORE_LOCKED();
+  if ((pcb == NULL) || (ipaddr == NULL)) {
+    return ERR_VAL;
+  }
+  ip_addr_set_ipaddr(&pcb->remote_ip, ipaddr);
+#if LWIP_IPV6 && LWIP_IPV6_SCOPES
+  /* If the given IP address should have a zone but doesn't, assign one now,
+   * using the bound address to make a more informed decision when possible. */
+  if (IP_IS_V6(&pcb->remote_ip) &&
+      ip6_addr_lacks_zone(ip_2_ip6(&pcb->remote_ip), IP6_UNKNOWN)) {
+    ip6_addr_select_zone(ip_2_ip6(&pcb->remote_ip), ip_2_ip6(&pcb->local_ip));
+  }
+#endif /* LWIP_IPV6 && LWIP_IPV6_SCOPES */
+  raw_set_flags(pcb, RAW_FLAGS_CONNECTED);
+  return ERR_OK;
+}
+
+/**
+ * @ingroup raw_raw
+ * Disconnect a RAW PCB.
+ *
+ * @param pcb the raw pcb to disconnect.
+ */
+void
+raw_disconnect(struct raw_pcb *pcb)
+{
+  LWIP_ASSERT_CORE_LOCKED();
+  /* reset remote address association */
+#if LWIP_IPV4 && LWIP_IPV6
+  if (IP_IS_ANY_TYPE_VAL(pcb->local_ip)) {
+    ip_addr_copy(pcb->remote_ip, *IP_ANY_TYPE);
+  } else {
+#endif
+    ip_addr_set_any(IP_IS_V6_VAL(pcb->remote_ip), &pcb->remote_ip);
+#if LWIP_IPV4 && LWIP_IPV6
+  }
+#endif
+  pcb->netif_idx = NETIF_NO_INDEX;
+  /* mark PCB as unconnected */
+  raw_clear_flags(pcb, RAW_FLAGS_CONNECTED);
+}
+
+/**
+ * @ingroup raw_raw
+ * Set the callback function for received packets that match the
+ * raw PCB's protocol and binding.
+ *
+ * The callback function MUST either
+ * - eat the packet by calling pbuf_free() and returning non-zero. The
+ *   packet will not be passed to other raw PCBs or other protocol layers.
+ * - not free the packet, and return zero. The packet will be matched
+ *   against further PCBs and/or forwarded to another protocol layers.
+ */
+void
+raw_recv(struct raw_pcb *pcb, raw_recv_fn recv, void *recv_arg)
+{
+  LWIP_ASSERT_CORE_LOCKED();
+  /* remember recv() callback and user data */
+  pcb->recv = recv;
+  pcb->recv_arg = recv_arg;
+}
+
+/**
+ * @ingroup raw_raw
+ * Send the raw IP packet to the given address. An IP header will be prepended
+ * to the packet, unless the RAW_FLAGS_HDRINCL flag is set on the PCB. In that
+ * case, the packet must include an IP header, which will then be sent as is.
+ *
+ * @param pcb the raw pcb which to send
+ * @param p the IP payload to send
+ * @param ipaddr the destination address of the IP packet
+ *
+ */
+err_t
+raw_sendto(struct raw_pcb *pcb, struct pbuf *p, const ip_addr_t *ipaddr)
+{
+  struct netif *netif;
+  const ip_addr_t *src_ip;
+
+  if ((pcb == NULL) || (ipaddr == NULL) || !IP_ADDR_PCB_VERSION_MATCH(pcb, ipaddr)) {
+    return ERR_VAL;
+  }
+
+  LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_TRACE, ("raw_sendto\n"));
+
+  if (pcb->netif_idx != NETIF_NO_INDEX) {
+    netif = netif_get_by_index(pcb->netif_idx);
+  } else {
+#if LWIP_MULTICAST_TX_OPTIONS
+    netif = NULL;
+    if (ip_addr_ismulticast(ipaddr)) {
+      /* For multicast-destined packets, use the user-provided interface index to
+       * determine the outgoing interface, if an interface index is set and a
+       * matching netif can be found. Otherwise, fall back to regular routing. */
+      netif = netif_get_by_index(pcb->mcast_ifindex);
+    }
+
+    if (netif == NULL)
+#endif /* LWIP_MULTICAST_TX_OPTIONS */
+    {
+      netif = ip_route(&pcb->local_ip, ipaddr);
+    }
+  }
+
+  if (netif == NULL) {
+    LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_LEVEL_WARNING, ("raw_sendto: No route to "));
+    ip_addr_debug_print(RAW_DEBUG | LWIP_DBG_LEVEL_WARNING, ipaddr);
+    LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_LEVEL_WARNING, ("\n"));
+    return ERR_RTE;
+  }
+
+  if (ip_addr_isany(&pcb->local_ip) || ip_addr_ismulticast(&pcb->local_ip)) {
+    /* use outgoing network interface IP address as source address */
+    src_ip = ip_netif_get_local_ip(netif, ipaddr);
+#if LWIP_IPV6
+    if (src_ip == NULL) {
+      return ERR_RTE;
+    }
+#endif /* LWIP_IPV6 */
+  } else {
+    /* use RAW PCB local IP address as source address */
+    src_ip = &pcb->local_ip;
+  }
+
+  return raw_sendto_if_src(pcb, p, ipaddr, netif, src_ip);
+}
+
+/**
+ * @ingroup raw_raw
+ * Send the raw IP packet to the given address, using a particular outgoing
+ * netif and source IP address. An IP header will be prepended to the packet,
+ * unless the RAW_FLAGS_HDRINCL flag is set on the PCB. In that case, the
+ * packet must include an IP header, which will then be sent as is.
+ *
+ * @param pcb RAW PCB used to send the data
+ * @param p chain of pbufs to be sent
+ * @param dst_ip destination IP address
+ * @param netif the netif used for sending
+ * @param src_ip source IP address
+ */
+err_t
+raw_sendto_if_src(struct raw_pcb *pcb, struct pbuf *p, const ip_addr_t *dst_ip,
+                  struct netif *netif, const ip_addr_t *src_ip)
+{
+  err_t err;
+  struct pbuf *q; /* q will be sent down the stack */
+  u16_t header_size;
+  u8_t ttl;
+
+  LWIP_ASSERT_CORE_LOCKED();
+
+  if ((pcb == NULL) || (dst_ip == NULL) || (netif == NULL) || (src_ip == NULL) ||
+      !IP_ADDR_PCB_VERSION_MATCH(pcb, src_ip) || !IP_ADDR_PCB_VERSION_MATCH(pcb, dst_ip)) {
+    return ERR_VAL;
+  }
+
+  header_size = (
+#if LWIP_IPV4 && LWIP_IPV6
+                  IP_IS_V6(dst_ip) ? IP6_HLEN : IP_HLEN);
+#elif LWIP_IPV4
+                  IP_HLEN);
+#else
+                  IP6_HLEN);
+#endif
+
+  /* Handle the HDRINCL option as an exception: none of the code below applies
+   * to this case, and sending the packet needs to be done differently too. */
+  if (pcb->flags & RAW_FLAGS_HDRINCL) {
+    /* A full header *must* be present in the first pbuf of the chain, as the
+     * output routines may access its fields directly. */
+    if (p->len < header_size) {
+      return ERR_VAL;
+    }
+    /* @todo multicast loop support, if at all desired for this scenario.. */
+    NETIF_SET_HINTS(netif, &pcb->netif_hints);
+    err = ip_output_if_hdrincl(p, src_ip, dst_ip, netif);
+    NETIF_RESET_HINTS(netif);
+    return err;
+  }
+
+  /* packet too large to add an IP header without causing an overflow? */
+  if ((u16_t)(p->tot_len + header_size) < p->tot_len) {
+    return ERR_MEM;
+  }
+  /* not enough space to add an IP header to first pbuf in given p chain? */
+  if (pbuf_add_header(p, header_size)) {
+    /* allocate header in new pbuf */
+    q = pbuf_alloc(PBUF_IP, 0, PBUF_RAM);
+    /* new header pbuf could not be allocated? */
+    if (q == NULL) {
+      LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS, ("raw_sendto: could not allocate header\n"));
+      return ERR_MEM;
+    }
+    if (p->tot_len != 0) {
+      /* chain header q in front of given pbuf p */
+      pbuf_chain(q, p);
+    }
+    /* { first pbuf q points to header pbuf } */
+    LWIP_DEBUGF(RAW_DEBUG, ("raw_sendto: added header pbuf %p before given pbuf %p\n", (void *)q, (void *)p));
+  } else {
+    /* first pbuf q equals given pbuf */
+    q = p;
+    if (pbuf_remove_header(q, header_size)) {
+      LWIP_ASSERT("Can't restore header we just removed!", 0);
+      return ERR_MEM;
+    }
+  }
+
+#if IP_SOF_BROADCAST
+  if (IP_IS_V4(dst_ip)) {
+    /* broadcast filter? */
+    if (!ip_get_option(pcb, SOF_BROADCAST) && ip_addr_isbroadcast(dst_ip, netif)) {
+      LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_LEVEL_WARNING, ("raw_sendto: SOF_BROADCAST not enabled on pcb %p\n", (void *)pcb));
+      /* free any temporary header pbuf allocated by pbuf_header() */
+      if (q != p) {
+        pbuf_free(q);
+      }
+      return ERR_VAL;
+    }
+  }
+#endif /* IP_SOF_BROADCAST */
+
+  /* Multicast Loop? */
+#if LWIP_MULTICAST_TX_OPTIONS
+  if (((pcb->flags & RAW_FLAGS_MULTICAST_LOOP) != 0) && ip_addr_ismulticast(dst_ip)) {
+    q->flags |= PBUF_FLAG_MCASTLOOP;
+  }
+#endif /* LWIP_MULTICAST_TX_OPTIONS */
+
+#if LWIP_IPV6
+  /* If requested, based on the IPV6_CHECKSUM socket option per RFC3542,
+     compute the checksum and update the checksum in the payload. */
+  if (IP_IS_V6(dst_ip) && pcb->chksum_reqd) {
+    u16_t chksum = ip6_chksum_pseudo(p, pcb->protocol, p->tot_len, ip_2_ip6(src_ip), ip_2_ip6(dst_ip));
+    LWIP_ASSERT("Checksum must fit into first pbuf", p->len >= (pcb->chksum_offset + 2));
+    SMEMCPY(((u8_t *)p->payload) + pcb->chksum_offset, &chksum, sizeof(u16_t));
+  }
+#endif
+
+  /* Determine TTL to use */
+#if LWIP_MULTICAST_TX_OPTIONS
+  ttl = (ip_addr_ismulticast(dst_ip) ? raw_get_multicast_ttl(pcb) : pcb->ttl);
+#else /* LWIP_MULTICAST_TX_OPTIONS */
+  ttl = pcb->ttl;
+#endif /* LWIP_MULTICAST_TX_OPTIONS */
+
+  NETIF_SET_HINTS(netif, &pcb->netif_hints);
+  err = ip_output_if(q, src_ip, dst_ip, ttl, pcb->tos, pcb->protocol, netif);
+  NETIF_RESET_HINTS(netif);
+
+  /* did we chain a header earlier? */
+  if (q != p) {
+    /* free the header */
+    pbuf_free(q);
+  }
+  return err;
+}
+
+/**
+ * @ingroup raw_raw
+ * Send the raw IP packet to the address given by raw_connect()
+ *
+ * @param pcb the raw pcb which to send
+ * @param p the IP payload to send
+ *
+ */
+err_t
+raw_send(struct raw_pcb *pcb, struct pbuf *p)
+{
+  return raw_sendto(pcb, p, &pcb->remote_ip);
+}
+
+/**
+ * @ingroup raw_raw
+ * Remove an RAW PCB.
+ *
+ * @param pcb RAW PCB to be removed. The PCB is removed from the list of
+ * RAW PCB's and the data structure is freed from memory.
+ *
+ * @see raw_new()
+ */
+void
+raw_remove(struct raw_pcb *pcb)
+{
+  struct raw_pcb *pcb2;
+  LWIP_ASSERT_CORE_LOCKED();
+  /* pcb to be removed is first in list? */
+  if (raw_pcbs == pcb) {
+    /* make list start at 2nd pcb */
+    raw_pcbs = raw_pcbs->next;
+    /* pcb not 1st in list */
+  } else {
+    for (pcb2 = raw_pcbs; pcb2 != NULL; pcb2 = pcb2->next) {
+      /* find pcb in raw_pcbs list */
+      if (pcb2->next != NULL && pcb2->next == pcb) {
+        /* remove pcb from list */
+        pcb2->next = pcb->next;
+        break;
+      }
+    }
+  }
+  memp_free(MEMP_RAW_PCB, pcb);
+}
+
+/**
+ * @ingroup raw_raw
+ * Create a RAW PCB.
+ *
+ * @return The RAW PCB which was created. NULL if the PCB data structure
+ * could not be allocated.
+ *
+ * @param proto the protocol number of the IPs payload (e.g. IP_PROTO_ICMP)
+ *
+ * @see raw_remove()
+ */
+struct raw_pcb *
+raw_new(u8_t proto)
+{
+  struct raw_pcb *pcb;
+
+  LWIP_DEBUGF(RAW_DEBUG | LWIP_DBG_TRACE, ("raw_new\n"));
+  LWIP_ASSERT_CORE_LOCKED();
+
+  pcb = (struct raw_pcb *)memp_malloc(MEMP_RAW_PCB);
+  /* could allocate RAW PCB? */
+  if (pcb != NULL) {
+    /* initialize PCB to all zeroes */
+    memset(pcb, 0, sizeof(struct raw_pcb));
+    pcb->protocol = proto;
+    pcb->ttl = RAW_TTL;
+#if LWIP_MULTICAST_TX_OPTIONS
+    raw_set_multicast_ttl(pcb, RAW_TTL);
+#endif /* LWIP_MULTICAST_TX_OPTIONS */
+    pcb_tci_init(pcb);
+    pcb->next = raw_pcbs;
+    raw_pcbs = pcb;
+  }
+  return pcb;
+}
+
+/**
+ * @ingroup raw_raw
+ * Create a RAW PCB for specific IP type.
+ *
+ * @return The RAW PCB which was created. NULL if the PCB data structure
+ * could not be allocated.
+ *
+ * @param type IP address type, see @ref lwip_ip_addr_type definitions.
+ * If you want to listen to IPv4 and IPv6 (dual-stack) packets,
+ * supply @ref IPADDR_TYPE_ANY as argument and bind to @ref IP_ANY_TYPE.
+ * @param proto the protocol number (next header) of the IPv6 packet payload
+ *              (e.g. IP6_NEXTH_ICMP6)
+ *
+ * @see raw_remove()
+ */
+struct raw_pcb *
+raw_new_ip_type(u8_t type, u8_t proto)
+{
+  struct raw_pcb *pcb;
+  LWIP_ASSERT_CORE_LOCKED();
+  pcb = raw_new(proto);
+#if LWIP_IPV4 && LWIP_IPV6
+  if (pcb != NULL) {
+    IP_SET_TYPE_VAL(pcb->local_ip,  type);
+    IP_SET_TYPE_VAL(pcb->remote_ip, type);
+  }
+#else /* LWIP_IPV4 && LWIP_IPV6 */
+  LWIP_UNUSED_ARG(type);
+#endif /* LWIP_IPV4 && LWIP_IPV6 */
+  return pcb;
+}
+
+/** This function is called from netif.c when address is changed
+ *
+ * @param old_addr IP address of the netif before change
+ * @param new_addr IP address of the netif after change
+ */
+void raw_netif_ip_addr_changed(const ip_addr_t *old_addr, const ip_addr_t *new_addr)
+{
+  struct raw_pcb *rpcb;
+
+  if (!ip_addr_isany(old_addr) && !ip_addr_isany(new_addr)) {
+    for (rpcb = raw_pcbs; rpcb != NULL; rpcb = rpcb->next) {
+      /* PCB bound to current local interface address? */
+      if (ip_addr_eq(&rpcb->local_ip, old_addr)) {
+        /* The PCB is bound to the old ipaddr and
+         * is set to bound to the new one instead */
+        ip_addr_copy(rpcb->local_ip, *new_addr);
+      }
+    }
+  }
+}
+
+#endif /* LWIP_RAW */

Drivers/LwIP/src/core/stats.c

@@ -0,0 +1,168 @@
+/**
+ * @file
+ * Statistics module
+ *
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+
+#include "lwip/opt.h"
+
+#if LWIP_STATS /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/def.h"
+#include "lwip/stats.h"
+#include "lwip/mem.h"
+#include "lwip/debug.h"
+
+#include <string.h>
+
+struct stats_ lwip_stats;
+
+void
+stats_init(void)
+{
+#ifdef LWIP_DEBUG
+#if MEM_STATS
+  lwip_stats.mem.name = "MEM";
+#endif /* MEM_STATS */
+#endif /* LWIP_DEBUG */
+}
+
+#if LWIP_STATS_DISPLAY
+void
+stats_display_proto(struct stats_proto *proto, const char *name)
+{
+  LWIP_PLATFORM_DIAG(("\n%s\n\t", name));
+  LWIP_PLATFORM_DIAG(("xmit: %"STAT_COUNTER_F"\n\t", proto->xmit));
+  LWIP_PLATFORM_DIAG(("recv: %"STAT_COUNTER_F"\n\t", proto->recv));
+  LWIP_PLATFORM_DIAG(("fw: %"STAT_COUNTER_F"\n\t", proto->fw));
+  LWIP_PLATFORM_DIAG(("drop: %"STAT_COUNTER_F"\n\t", proto->drop));
+  LWIP_PLATFORM_DIAG(("chkerr: %"STAT_COUNTER_F"\n\t", proto->chkerr));
+  LWIP_PLATFORM_DIAG(("lenerr: %"STAT_COUNTER_F"\n\t", proto->lenerr));
+  LWIP_PLATFORM_DIAG(("memerr: %"STAT_COUNTER_F"\n\t", proto->memerr));
+  LWIP_PLATFORM_DIAG(("rterr: %"STAT_COUNTER_F"\n\t", proto->rterr));
+  LWIP_PLATFORM_DIAG(("proterr: %"STAT_COUNTER_F"\n\t", proto->proterr));
+  LWIP_PLATFORM_DIAG(("opterr: %"STAT_COUNTER_F"\n\t", proto->opterr));
+  LWIP_PLATFORM_DIAG(("err: %"STAT_COUNTER_F"\n\t", proto->err));
+  LWIP_PLATFORM_DIAG(("cachehit: %"STAT_COUNTER_F"\n", proto->cachehit));
+}
+
+#if IGMP_STATS || MLD6_STATS
+void
+stats_display_igmp(struct stats_igmp *igmp, const char *name)
+{
+  LWIP_PLATFORM_DIAG(("\n%s\n\t", name));
+  LWIP_PLATFORM_DIAG(("xmit: %"STAT_COUNTER_F"\n\t", igmp->xmit));
+  LWIP_PLATFORM_DIAG(("recv: %"STAT_COUNTER_F"\n\t", igmp->recv));
+  LWIP_PLATFORM_DIAG(("drop: %"STAT_COUNTER_F"\n\t", igmp->drop));
+  LWIP_PLATFORM_DIAG(("chkerr: %"STAT_COUNTER_F"\n\t", igmp->chkerr));
+  LWIP_PLATFORM_DIAG(("lenerr: %"STAT_COUNTER_F"\n\t", igmp->lenerr));
+  LWIP_PLATFORM_DIAG(("memerr: %"STAT_COUNTER_F"\n\t", igmp->memerr));
+  LWIP_PLATFORM_DIAG(("proterr: %"STAT_COUNTER_F"\n\t", igmp->proterr));
+  LWIP_PLATFORM_DIAG(("rx_v1: %"STAT_COUNTER_F"\n\t", igmp->rx_v1));
+  LWIP_PLATFORM_DIAG(("rx_group: %"STAT_COUNTER_F"\n\t", igmp->rx_group));
+  LWIP_PLATFORM_DIAG(("rx_general: %"STAT_COUNTER_F"\n\t", igmp->rx_general));
+  LWIP_PLATFORM_DIAG(("rx_report: %"STAT_COUNTER_F"\n\t", igmp->rx_report));
+  LWIP_PLATFORM_DIAG(("tx_join: %"STAT_COUNTER_F"\n\t", igmp->tx_join));
+  LWIP_PLATFORM_DIAG(("tx_leave: %"STAT_COUNTER_F"\n\t", igmp->tx_leave));
+  LWIP_PLATFORM_DIAG(("tx_report: %"STAT_COUNTER_F"\n", igmp->tx_report));
+}
+#endif /* IGMP_STATS || MLD6_STATS */
+
+#if MEM_STATS || MEMP_STATS
+void
+stats_display_mem(struct stats_mem *mem, const char *name)
+{
+  LWIP_PLATFORM_DIAG(("\nMEM %s\n\t", name));
+  LWIP_PLATFORM_DIAG(("avail: %"MEM_SIZE_F"\n\t", mem->avail));
+  LWIP_PLATFORM_DIAG(("used: %"MEM_SIZE_F"\n\t", mem->used));
+  LWIP_PLATFORM_DIAG(("max: %"MEM_SIZE_F"\n\t", mem->max));
+  LWIP_PLATFORM_DIAG(("err: %"STAT_COUNTER_F"\n", mem->err));
+}
+
+#if MEMP_STATS
+void
+stats_display_memp(struct stats_mem *mem, int idx)
+{
+  if (idx < MEMP_MAX) {
+    stats_display_mem(mem, mem->name);
+  }
+}
+#endif /* MEMP_STATS */
+#endif /* MEM_STATS || MEMP_STATS */
+
+#if SYS_STATS
+void
+stats_display_sys(struct stats_sys *sys)
+{
+  LWIP_PLATFORM_DIAG(("\nSYS\n\t"));
+  LWIP_PLATFORM_DIAG(("sem.used:  %"STAT_COUNTER_F"\n\t", sys->sem.used));
+  LWIP_PLATFORM_DIAG(("sem.max:   %"STAT_COUNTER_F"\n\t", sys->sem.max));
+  LWIP_PLATFORM_DIAG(("sem.err:   %"STAT_COUNTER_F"\n\t", sys->sem.err));
+  LWIP_PLATFORM_DIAG(("mutex.used: %"STAT_COUNTER_F"\n\t", sys->mutex.used));
+  LWIP_PLATFORM_DIAG(("mutex.max:  %"STAT_COUNTER_F"\n\t", sys->mutex.max));
+  LWIP_PLATFORM_DIAG(("mutex.err:  %"STAT_COUNTER_F"\n\t", sys->mutex.err));
+  LWIP_PLATFORM_DIAG(("mbox.used:  %"STAT_COUNTER_F"\n\t", sys->mbox.used));
+  LWIP_PLATFORM_DIAG(("mbox.max:   %"STAT_COUNTER_F"\n\t", sys->mbox.max));
+  LWIP_PLATFORM_DIAG(("mbox.err:   %"STAT_COUNTER_F"\n", sys->mbox.err));
+}
+#endif /* SYS_STATS */
+
+void
+stats_display(void)
+{
+  s16_t i;
+
+  LINK_STATS_DISPLAY();
+  ETHARP_STATS_DISPLAY();
+  IPFRAG_STATS_DISPLAY();
+  IP6_FRAG_STATS_DISPLAY();
+  IP_STATS_DISPLAY();
+  ND6_STATS_DISPLAY();
+  IP6_STATS_DISPLAY();
+  IGMP_STATS_DISPLAY();
+  MLD6_STATS_DISPLAY();
+  ICMP_STATS_DISPLAY();
+  ICMP6_STATS_DISPLAY();
+  UDP_STATS_DISPLAY();
+  TCP_STATS_DISPLAY();
+  MEM_STATS_DISPLAY();
+  for (i = 0; i < MEMP_MAX; i++) {
+    MEMP_STATS_DISPLAY(i);
+  }
+  SYS_STATS_DISPLAY();
+}
+#endif /* LWIP_STATS_DISPLAY */
+
+#endif /* LWIP_STATS */

Drivers/LwIP/src/core/sys.c

@@ -0,0 +1,148 @@
+/**
+ * @file
+ * lwIP Operating System abstraction
+ *
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+
+/**
+ * @defgroup sys_layer Porting (system abstraction layer)
+ * @ingroup lwip
+ *
+ * @defgroup sys_os OS abstraction layer
+ * @ingroup sys_layer
+ * No need to implement functions in this section in NO_SYS mode.
+ * The OS-specific code should be implemented in arch/sys_arch.h
+ * and sys_arch.c of your port.
+ *
+ * The operating system emulation layer provides a common interface
+ * between the lwIP code and the underlying operating system kernel. The
+ * general idea is that porting lwIP to new architectures requires only
+ * small changes to a few header files and a new sys_arch
+ * implementation. It is also possible to do a sys_arch implementation
+ * that does not rely on any underlying operating system.
+ *
+ * The sys_arch provides semaphores, mailboxes and mutexes to lwIP. For the full
+ * lwIP functionality, multiple threads support can be implemented in the
+ * sys_arch, but this is not required for the basic lwIP
+ * functionality. Timer scheduling is implemented in lwIP, but can be implemented
+ * by the sys_arch port (LWIP_TIMERS_CUSTOM==1).
+ *
+ * In addition to the source file providing the functionality of sys_arch,
+ * the OS emulation layer must provide several header files defining
+ * macros used throughout lwip.  The files required and the macros they
+ * must define are listed below the sys_arch description.
+ *
+ * Since lwIP 1.4.0, semaphore, mutexes and mailbox functions are prototyped in a way that
+ * allows both using pointers or actual OS structures to be used. This way, memory
+ * required for such types can be either allocated in place (globally or on the
+ * stack) or on the heap (allocated internally in the "*_new()" functions).
+ *
+ * Note:
+ * -----
+ * Be careful with using mem_malloc() in sys_arch. When malloc() refers to
+ * mem_malloc() you can run into a circular function call problem. In mem.c
+ * mem_init() tries to allocate a semaphore using mem_malloc, which of course
+ * can't be performed when sys_arch uses mem_malloc.
+ *
+ * @defgroup sys_sem Semaphores
+ * @ingroup sys_os
+ * Semaphores can be either counting or binary - lwIP works with both
+ * kinds.
+ * Semaphores are represented by the type "sys_sem_t" which is typedef'd
+ * in the sys_arch.h file. Mailboxes are equivalently represented by the
+ * type "sys_mbox_t". Mutexes are represented by the type "sys_mutex_t".
+ * lwIP does not place any restrictions on how these types are represented
+ * internally.
+ *
+ * @defgroup sys_mutex Mutexes
+ * @ingroup sys_os
+ * Mutexes are recommended to correctly handle priority inversion,
+ * especially if you use LWIP_CORE_LOCKING .
+ *
+ * @defgroup sys_mbox Mailboxes
+ * @ingroup sys_os
+ * Mailboxes should be implemented as a queue which allows multiple messages
+ * to be posted (implementing as a rendez-vous point where only one message can be
+ * posted at a time can have a highly negative impact on performance). A message
+ * in a mailbox is just a pointer, nothing more.
+ *
+ * @defgroup sys_time Time
+ * @ingroup sys_layer
+ *
+ * @defgroup sys_prot Critical sections
+ * @ingroup sys_layer
+ * Used to protect short regions of code against concurrent access.
+ * - Your system is a bare-metal system (probably with an RTOS)
+ *   and interrupts are under your control:
+ *   Implement this as LockInterrupts() / UnlockInterrupts()
+ * - Your system uses an RTOS with deferred interrupt handling from a
+ *   worker thread: Implement as a global mutex or lock/unlock scheduler
+ * - Your system uses a high-level OS with e.g. POSIX signals:
+ *   Implement as a global mutex
+ *
+ * @defgroup sys_misc Misc
+ * @ingroup sys_os
+ */
+
+#include "lwip/opt.h"
+
+#include "lwip/sys.h"
+
+/* Most of the functions defined in sys.h must be implemented in the
+ * architecture-dependent file sys_arch.c */
+
+#if !NO_SYS
+
+#ifndef sys_msleep
+/**
+ * Sleep for some ms. Timeouts are NOT processed while sleeping.
+ *
+ * @param ms number of milliseconds to sleep
+ */
+void
+sys_msleep(u32_t ms)
+{
+  if (ms > 0) {
+    sys_sem_t delaysem;
+    err_t err = sys_sem_new(&delaysem, 0);
+    if (err == ERR_OK) {
+      sys_arch_sem_wait(&delaysem, ms);
+      sys_sem_free(&delaysem);
+    }
+  }
+}
+#endif /* sys_msleep */
+
+#endif /* !NO_SYS */

Drivers/LwIP/src/core/timeouts.c

@@ -0,0 +1,451 @@
+/**
+ * @file
+ * Stack-internal timers implementation.
+ * This file includes timer callbacks for stack-internal timers as well as
+ * functions to set up or stop timers and check for expired timers.
+ *
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Adam Dunkels <adam@sics.se>
+ *         Simon Goldschmidt
+ *
+ */
+
+#include "lwip/opt.h"
+
+#include "lwip/timeouts.h"
+#include "lwip/priv/tcp_priv.h"
+
+#include "lwip/def.h"
+#include "lwip/memp.h"
+#include "lwip/priv/tcpip_priv.h"
+
+#include "lwip/ip4_frag.h"
+#include "lwip/etharp.h"
+#include "lwip/dhcp.h"
+#include "lwip/acd.h"
+#include "lwip/igmp.h"
+#include "lwip/dns.h"
+#include "lwip/nd6.h"
+#include "lwip/ip6_frag.h"
+#include "lwip/mld6.h"
+#include "lwip/dhcp6.h"
+#include "lwip/sys.h"
+#include "lwip/pbuf.h"
+
+#if LWIP_DEBUG_TIMERNAMES
+#define HANDLER(x) x, #x
+#else /* LWIP_DEBUG_TIMERNAMES */
+#define HANDLER(x) x
+#endif /* LWIP_DEBUG_TIMERNAMES */
+
+#define LWIP_MAX_TIMEOUT  0x7fffffff
+
+/* Check if timer's expiry time is greater than time and care about u32_t wraparounds */
+#define TIME_LESS_THAN(t, compare_to) ( (((u32_t)((t)-(compare_to))) > LWIP_MAX_TIMEOUT) ? 1 : 0 )
+
+/** This array contains all stack-internal cyclic timers. To get the number of
+ * timers, use LWIP_ARRAYSIZE() */
+const struct lwip_cyclic_timer lwip_cyclic_timers[] = {
+#if LWIP_TCP
+  /* The TCP timer is a special case: it does not have to run always and
+     is triggered to start from TCP using tcp_timer_needed() */
+  {TCP_TMR_INTERVAL, HANDLER(tcp_tmr)},
+#endif /* LWIP_TCP */
+#if LWIP_IPV4
+#if IP_REASSEMBLY
+  {IP_TMR_INTERVAL, HANDLER(ip_reass_tmr)},
+#endif /* IP_REASSEMBLY */
+#if LWIP_ARP
+  {ARP_TMR_INTERVAL, HANDLER(etharp_tmr)},
+#endif /* LWIP_ARP */
+#if LWIP_DHCP
+  {DHCP_COARSE_TIMER_MSECS, HANDLER(dhcp_coarse_tmr)},
+  {DHCP_FINE_TIMER_MSECS, HANDLER(dhcp_fine_tmr)},
+#endif /* LWIP_DHCP */
+#if LWIP_ACD
+  {ACD_TMR_INTERVAL, HANDLER(acd_tmr)},
+#endif /* LWIP_ACD */
+#if LWIP_IGMP
+  {IGMP_TMR_INTERVAL, HANDLER(igmp_tmr)},
+#endif /* LWIP_IGMP */
+#endif /* LWIP_IPV4 */
+#if LWIP_DNS
+  {DNS_TMR_INTERVAL, HANDLER(dns_tmr)},
+#endif /* LWIP_DNS */
+#if LWIP_IPV6
+  {ND6_TMR_INTERVAL, HANDLER(nd6_tmr)},
+#if LWIP_IPV6_REASS
+  {IP6_REASS_TMR_INTERVAL, HANDLER(ip6_reass_tmr)},
+#endif /* LWIP_IPV6_REASS */
+#if LWIP_IPV6_MLD
+  {MLD6_TMR_INTERVAL, HANDLER(mld6_tmr)},
+#endif /* LWIP_IPV6_MLD */
+#if LWIP_IPV6_DHCP6
+  {DHCP6_TIMER_MSECS, HANDLER(dhcp6_tmr)},
+#endif /* LWIP_IPV6_DHCP6 */
+#endif /* LWIP_IPV6 */
+};
+const int lwip_num_cyclic_timers = LWIP_ARRAYSIZE(lwip_cyclic_timers);
+
+#if LWIP_TIMERS && !LWIP_TIMERS_CUSTOM
+
+/** The one and only timeout list */
+static struct sys_timeo *next_timeout;
+
+static u32_t current_timeout_due_time;
+
+#if LWIP_TESTMODE
+struct sys_timeo**
+sys_timeouts_get_next_timeout(void)
+{
+  return &next_timeout;
+}
+#endif
+
+#if LWIP_TCP
+/** global variable that shows if the tcp timer is currently scheduled or not */
+static int tcpip_tcp_timer_active;
+
+/**
+ * Timer callback function that calls tcp_tmr() and reschedules itself.
+ *
+ * @param arg unused argument
+ */
+static void
+tcpip_tcp_timer(void *arg)
+{
+  LWIP_UNUSED_ARG(arg);
+
+  /* call TCP timer handler */
+  tcp_tmr();
+  /* timer still needed? */
+  if (tcp_active_pcbs || tcp_tw_pcbs) {
+    /* restart timer */
+    sys_timeout(TCP_TMR_INTERVAL, tcpip_tcp_timer, NULL);
+  } else {
+    /* disable timer */
+    tcpip_tcp_timer_active = 0;
+  }
+}
+
+/**
+ * Called from TCP_REG when registering a new PCB:
+ * the reason is to have the TCP timer only running when
+ * there are active (or time-wait) PCBs.
+ */
+void
+tcp_timer_needed(void)
+{
+  LWIP_ASSERT_CORE_LOCKED();
+
+  /* timer is off but needed again? */
+  if (!tcpip_tcp_timer_active && (tcp_active_pcbs || tcp_tw_pcbs)) {
+    /* enable and start timer */
+    tcpip_tcp_timer_active = 1;
+    sys_timeout(TCP_TMR_INTERVAL, tcpip_tcp_timer, NULL);
+  }
+}
+#endif /* LWIP_TCP */
+
+static void
+#if LWIP_DEBUG_TIMERNAMES
+sys_timeout_abs(u32_t abs_time, sys_timeout_handler handler, void *arg, const char *handler_name)
+#else /* LWIP_DEBUG_TIMERNAMES */
+sys_timeout_abs(u32_t abs_time, sys_timeout_handler handler, void *arg)
+#endif
+{
+  struct sys_timeo *timeout, *t;
+
+  timeout = (struct sys_timeo *)memp_malloc(MEMP_SYS_TIMEOUT);
+  if (timeout == NULL) {
+    LWIP_ASSERT("sys_timeout: timeout != NULL, pool MEMP_SYS_TIMEOUT is empty", timeout != NULL);
+    return;
+  }
+
+  timeout->next = NULL;
+  timeout->h = handler;
+  timeout->arg = arg;
+  timeout->time = abs_time;
+
+#if LWIP_DEBUG_TIMERNAMES
+  timeout->handler_name = handler_name;
+  LWIP_DEBUGF(TIMERS_DEBUG, ("sys_timeout: %p abs_time=%"U32_F" handler=%s arg=%p\n",
+                             (void *)timeout, abs_time, handler_name, (void *)arg));
+#endif /* LWIP_DEBUG_TIMERNAMES */
+
+  if (next_timeout == NULL) {
+    next_timeout = timeout;
+    return;
+  }
+  if (TIME_LESS_THAN(timeout->time, next_timeout->time)) {
+    timeout->next = next_timeout;
+    next_timeout = timeout;
+  } else {
+    for (t = next_timeout; t != NULL; t = t->next) {
+      if ((t->next == NULL) || TIME_LESS_THAN(timeout->time, t->next->time)) {
+        timeout->next = t->next;
+        t->next = timeout;
+        break;
+      }
+    }
+  }
+}
+
+/**
+ * Timer callback function that calls cyclic->handler() and reschedules itself.
+ *
+ * @param arg unused argument
+ */
+#if !LWIP_TESTMODE
+static
+#endif
+void
+lwip_cyclic_timer(void *arg)
+{
+  u32_t now;
+  u32_t next_timeout_time;
+  const struct lwip_cyclic_timer *cyclic = (const struct lwip_cyclic_timer *)arg;
+
+#if LWIP_DEBUG_TIMERNAMES
+  LWIP_DEBUGF(TIMERS_DEBUG, ("tcpip: %s()\n", cyclic->handler_name));
+#endif
+  cyclic->handler();
+
+  now = sys_now();
+  next_timeout_time = (u32_t)(current_timeout_due_time + cyclic->interval_ms);  /* overflow handled by TIME_LESS_THAN macro */
+  if (TIME_LESS_THAN(next_timeout_time, now)) {
+    /* timer would immediately expire again -> "overload" -> restart without any correction */
+#if LWIP_DEBUG_TIMERNAMES
+    sys_timeout_abs((u32_t)(now + cyclic->interval_ms), lwip_cyclic_timer, arg, cyclic->handler_name);
+#else
+    sys_timeout_abs((u32_t)(now + cyclic->interval_ms), lwip_cyclic_timer, arg);
+#endif
+
+  } else {
+    /* correct cyclic interval with handler execution delay and sys_check_timeouts jitter */
+#if LWIP_DEBUG_TIMERNAMES
+    sys_timeout_abs(next_timeout_time, lwip_cyclic_timer, arg, cyclic->handler_name);
+#else
+    sys_timeout_abs(next_timeout_time, lwip_cyclic_timer, arg);
+#endif
+  }
+}
+
+/** Initialize this module */
+void sys_timeouts_init(void)
+{
+  size_t i;
+  /* tcp_tmr() at index 0 is started on demand */
+  for (i = (LWIP_TCP ? 1 : 0); i < LWIP_ARRAYSIZE(lwip_cyclic_timers); i++) {
+    /* we have to cast via size_t to get rid of const warning
+      (this is OK as cyclic_timer() casts back to const* */
+    sys_timeout(lwip_cyclic_timers[i].interval_ms, lwip_cyclic_timer, LWIP_CONST_CAST(void *, &lwip_cyclic_timers[i]));
+  }
+}
+
+/**
+ * Create a one-shot timer (aka timeout). Timeouts are processed in the
+ * following cases:
+ * - while waiting for a message using sys_timeouts_mbox_fetch()
+ * - by calling sys_check_timeouts() (NO_SYS==1 only)
+ *
+ * @param msecs time in milliseconds after that the timer should expire
+ * @param handler callback function to call when msecs have elapsed
+ * @param arg argument to pass to the callback function
+ */
+#if LWIP_DEBUG_TIMERNAMES
+void
+sys_timeout_debug(u32_t msecs, sys_timeout_handler handler, void *arg, const char *handler_name)
+#else /* LWIP_DEBUG_TIMERNAMES */
+void
+sys_timeout(u32_t msecs, sys_timeout_handler handler, void *arg)
+#endif /* LWIP_DEBUG_TIMERNAMES */
+{
+  u32_t next_timeout_time;
+
+  LWIP_ASSERT_CORE_LOCKED();
+
+  LWIP_ASSERT("Timeout time too long, max is LWIP_UINT32_MAX/4 msecs", msecs <= (LWIP_UINT32_MAX / 4));
+
+  next_timeout_time = (u32_t)(sys_now() + msecs); /* overflow handled by TIME_LESS_THAN macro */
+
+#if LWIP_DEBUG_TIMERNAMES
+  sys_timeout_abs(next_timeout_time, handler, arg, handler_name);
+#else
+  sys_timeout_abs(next_timeout_time, handler, arg);
+#endif
+}
+
+/**
+ * Go through timeout list (for this task only) and remove the first matching
+ * entry (subsequent entries remain untouched), even though the timeout has not
+ * triggered yet.
+ *
+ * @param handler callback function that would be called by the timeout
+ * @param arg callback argument that would be passed to handler
+*/
+void
+sys_untimeout(sys_timeout_handler handler, void *arg)
+{
+  struct sys_timeo *prev_t, *t;
+
+  LWIP_ASSERT_CORE_LOCKED();
+
+  if (next_timeout == NULL) {
+    return;
+  }
+
+  for (t = next_timeout, prev_t = NULL; t != NULL; prev_t = t, t = t->next) {
+    if ((t->h == handler) && (t->arg == arg)) {
+      /* We have a match */
+      /* Unlink from previous in list */
+      if (prev_t == NULL) {
+        next_timeout = t->next;
+      } else {
+        prev_t->next = t->next;
+      }
+      memp_free(MEMP_SYS_TIMEOUT, t);
+      return;
+    }
+  }
+  return;
+}
+
+/**
+ * @ingroup lwip_nosys
+ * Handle timeouts for NO_SYS==1 (i.e. without using
+ * tcpip_thread/sys_timeouts_mbox_fetch(). Uses sys_now() to call timeout
+ * handler functions when timeouts expire.
+ *
+ * Must be called periodically from your main loop.
+ */
+void
+sys_check_timeouts(void)
+{
+  u32_t now;
+
+  LWIP_ASSERT_CORE_LOCKED();
+
+  /* Process only timers expired at the start of the function. */
+  now = sys_now();
+
+  do {
+    struct sys_timeo *tmptimeout;
+    sys_timeout_handler handler;
+    void *arg;
+
+    PBUF_CHECK_FREE_OOSEQ();
+
+    tmptimeout = next_timeout;
+    if (tmptimeout == NULL) {
+      return;
+    }
+
+    if (TIME_LESS_THAN(now, tmptimeout->time)) {
+      return;
+    }
+
+    /* Timeout has expired */
+    next_timeout = tmptimeout->next;
+    handler = tmptimeout->h;
+    arg = tmptimeout->arg;
+    current_timeout_due_time = tmptimeout->time;
+#if LWIP_DEBUG_TIMERNAMES
+    if (handler != NULL) {
+      LWIP_DEBUGF(TIMERS_DEBUG, ("sct calling h=%s t=%"U32_F" arg=%p\n",
+                                 tmptimeout->handler_name, sys_now() - tmptimeout->time, arg));
+    }
+#endif /* LWIP_DEBUG_TIMERNAMES */
+    memp_free(MEMP_SYS_TIMEOUT, tmptimeout);
+    if (handler != NULL) {
+      handler(arg);
+    }
+    LWIP_TCPIP_THREAD_ALIVE();
+
+    /* Repeat until all expired timers have been called */
+  } while (1);
+}
+
+/** Rebase the timeout times to the current time.
+ * This is necessary if sys_check_timeouts() hasn't been called for a long
+ * time (e.g. while saving energy) to prevent all timer functions of that
+ * period being called.
+ */
+void
+sys_restart_timeouts(void)
+{
+  u32_t now;
+  u32_t base;
+  struct sys_timeo *t;
+
+  if (next_timeout == NULL) {
+    return;
+  }
+
+  now = sys_now();
+  base = next_timeout->time;
+
+  for (t = next_timeout; t != NULL; t = t->next) {
+    t->time = (t->time - base) + now;
+  }
+}
+
+/** Return the time left before the next timeout is due. If no timeouts are
+ * enqueued, returns 0xffffffff
+ */
+u32_t
+sys_timeouts_sleeptime(void)
+{
+  u32_t now;
+
+  LWIP_ASSERT_CORE_LOCKED();
+
+  if (next_timeout == NULL) {
+    return SYS_TIMEOUTS_SLEEPTIME_INFINITE;
+  }
+  now = sys_now();
+  if (TIME_LESS_THAN(next_timeout->time, now)) {
+    return 0;
+  } else {
+    u32_t ret = (u32_t)(next_timeout->time - now);
+    LWIP_ASSERT("invalid sleeptime", ret <= LWIP_MAX_TIMEOUT);
+    return ret;
+  }
+}
+
+#else /* LWIP_TIMERS && !LWIP_TIMERS_CUSTOM */
+/* Satisfy the TCP code which calls this function */
+void
+tcp_timer_needed(void)
+{
+}
+#endif /* LWIP_TIMERS && !LWIP_TIMERS_CUSTOM */