Diff: lwip/core/ipv4/autoip.c

Revision:

0:350011bf8be7

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lwip/core/ipv4/autoip.c	Tue Nov 23 14:15:36 2010 +0000
@@ -0,0 +1,541 @@
+/**
+ * @file
+ * AutoIP Automatic LinkLocal IP Configuration
+ *
+ */
+
+/*
+ *
+ * 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>
+ *
+ * This is a AutoIP implementation for the lwIP TCP/IP stack. It aims to conform
+ * with RFC 3927.
+ *
+ *
+ * Please coordinate changes and requests with Dominik Spies
+ * <kontakt@dspies.de>
+ */
+
+/*******************************************************************************
+ * USAGE:
+ * 
+ * define LWIP_AUTOIP 1  in your lwipopts.h
+ * 
+ * If you don't use tcpip.c (so, don't call, you don't call tcpip_init):
+ * - First, call autoip_init().
+ * - call autoip_tmr() all AUTOIP_TMR_INTERVAL msces,
+ *   that should be defined in autoip.h.
+ *   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 ....
+ *
+ * Without DHCP:
+ * - Call autoip_start() after netif_add().
+ * 
+ * With DHCP:
+ * - define LWIP_DHCP_AUTOIP_COOP 1 in your lwipopts.h.
+ * - Configure your DHCP Client.
+ *
+ */
+
+#include "lwip/opt.h"
+
+#if 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 "netif/etharp.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+/* 169.254.0.0 */
+#define AUTOIP_NET         0xA9FE0000
+/* 169.254.1.0 */
+#define AUTOIP_RANGE_START (AUTOIP_NET | 0x0100)
+/* 169.254.254.255 */
+#define AUTOIP_RANGE_END   (AUTOIP_NET | 0xFEFF)
+
+
+/** Pseudo random macro based on netif informations.
+ * You could use "rand()" from the C Library if you define LWIP_AUTOIP_RAND in lwipopts.h */
+#ifndef LWIP_AUTOIP_RAND
+#define LWIP_AUTOIP_RAND(netif) ( (((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))) + \
+                                   (netif->autoip?netif->autoip->tried_llipaddr:0))
+#endif /* LWIP_AUTOIP_RAND */
+
+/**
+ * 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) \
+  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 */
+
+/* static functions */
+static void autoip_handle_arp_conflict(struct netif *netif);
+
+/* creates a pseudo random LL IP-Address for a network interface */
+static void autoip_create_addr(struct netif *netif, ip_addr_t *ipaddr);
+
+/* sends an ARP probe */
+static err_t autoip_arp_probe(struct netif *netif);
+
+/* sends an ARP announce */
+static err_t autoip_arp_announce(struct netif *netif);
+
+/* configure interface for use with current LL IP-Address */
+static err_t autoip_bind(struct netif *netif);
+
+/* start sending probes for llipaddr */
+static void autoip_start_probing(struct netif *netif);
+
+/**
+ * Initialize this module
+ */
+void
+autoip_init(void)
+{
+  LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, ("autoip_init()\n"));
+}
+
+/** 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 dhcp (uninitialised) dhcp struct allocated by the application
+ */
+void
+autoip_set_struct(struct netif *netif, struct autoip *autoip)
+{
+  LWIP_ASSERT("netif != NULL", netif != NULL);
+  LWIP_ASSERT("autoip != NULL", autoip != NULL);
+  LWIP_ASSERT("netif already has a struct autoip set", netif->autoip == NULL);
+
+  /* clear data structure */
+  memset(autoip, 0, sizeof(struct autoip));
+  /* autoip->state = AUTOIP_STATE_OFF; */
+  netif->autoip = autoip;
+}
+
+/** Restart AutoIP client and check the next address (conflict detected)
+ *
+ * @param netif The netif under AutoIP control
+ */
+static void
+autoip_restart(struct netif *netif)
+{
+  netif->autoip->tried_llipaddr++;
+  autoip_start(netif);
+}
+
+/**
+ * Handle a IP address conflict after an ARP conflict detection
+ */
+static void
+autoip_handle_arp_conflict(struct netif *netif)
+{
+  /* Somehow detect if we are defending or retreating */
+  unsigned char defend = 1; /* tbd */
+
+  if(defend) {
+    if(netif->autoip->lastconflict > 0) {
+      /* retreat, there was a conflicting ARP in the last
+       * DEFEND_INTERVAL seconds
+       */
+      LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
+        ("autoip_handle_arp_conflict(): we are defending, but in DEFEND_INTERVAL, retreating\n"));
+
+      /* TODO: close all TCP sessions */
+      autoip_restart(netif);
+    } else {
+      LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
+        ("autoip_handle_arp_conflict(): we are defend, send ARP Announce\n"));
+      autoip_arp_announce(netif);
+      netif->autoip->lastconflict = DEFEND_INTERVAL * AUTOIP_TICKS_PER_SECOND;
+    }
+  } else {
+    LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
+      ("autoip_handle_arp_conflict(): we do not defend, retreating\n"));
+    /* TODO: close all TCP sessions */
+    autoip_restart(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, ip_addr_t *ipaddr)
+{
+  /* 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 = ntohl(LWIP_AUTOIP_CREATE_SEED_ADDR(netif));
+  addr += netif->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, 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)(netif->autoip->tried_llipaddr), ip4_addr1_16(ipaddr), ip4_addr2_16(ipaddr),
+    ip4_addr3_16(ipaddr), ip4_addr4_16(ipaddr)));
+}
+
+/**
+ * Sends an ARP probe from a network interface
+ *
+ * @param netif network interface used to send the probe
+ */
+static err_t
+autoip_arp_probe(struct netif *netif)
+{
+  return etharp_raw(netif, (struct eth_addr *)netif->hwaddr, &ethbroadcast,
+    (struct eth_addr *)netif->hwaddr, IP_ADDR_ANY, &ethzero,
+    &netif->autoip->llipaddr, ARP_REQUEST);
+}
+
+/**
+ * Sends an ARP announce from a network interface
+ *
+ * @param netif network interface used to send the announce
+ */
+static err_t
+autoip_arp_announce(struct netif *netif)
+{
+  return etharp_raw(netif, (struct eth_addr *)netif->hwaddr, &ethbroadcast,
+    (struct eth_addr *)netif->hwaddr, &netif->autoip->llipaddr, &ethzero,
+    &netif->autoip->llipaddr, ARP_REQUEST);
+}
+
+/**
+ * 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;
+  ip_addr_t sn_mask, gw_addr;
+
+  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_ipaddr(netif, &autoip->llipaddr);
+  netif_set_netmask(netif, &sn_mask);
+  netif_set_gw(netif, &gw_addr);  
+
+  /* bring the interface up */
+  netif_set_up(netif);
+
+  return ERR_OK;
+}
+
+/**
+ * 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;
+  err_t result = ERR_OK;
+
+  if(netif_is_up(netif)) {
+    netif_set_down(netif);
+  }
+
+  /* Set IP-Address, Netmask and Gateway to 0 to make sure that
+   * ARP Packets are formed correctly
+   */
+  ip_addr_set_zero(&netif->ip_addr);
+  ip_addr_set_zero(&netif->netmask);
+  ip_addr_set_zero(&netif->gw);
+
+  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));
+  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_malloc(sizeof(struct autoip));
+    if(autoip == NULL) {
+      LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
+        ("autoip_start(): could not allocate autoip\n"));
+      return ERR_MEM;
+    }
+    memset(autoip, 0, sizeof(struct autoip));
+    /* store this AutoIP client in the netif */
+    netif->autoip = autoip;
+    LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, ("autoip_start(): allocated autoip"));
+  } else {
+    autoip->state = AUTOIP_STATE_OFF;
+    autoip->ttw = 0;
+    autoip->sent_num = 0;
+    ip_addr_set_zero(&autoip->llipaddr);
+    autoip->lastconflict = 0;
+  }
+
+  autoip_create_addr(netif, &(autoip->llipaddr));
+  autoip_start_probing(netif);
+
+  return result;
+}
+
+static void
+autoip_start_probing(struct netif *netif)
+{
+  struct autoip *autoip = netif->autoip;
+
+  autoip->state = AUTOIP_STATE_PROBING;
+  autoip->sent_num = 0;
+  LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
+     ("autoip_start_probing(): changing state to PROBING: %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
+      ip4_addr1_16(&netif->autoip->llipaddr), ip4_addr2_16(&netif->autoip->llipaddr),
+      ip4_addr3_16(&netif->autoip->llipaddr), ip4_addr4_16(&netif->autoip->llipaddr)));
+
+  /* time to wait to first probe, this is randomly
+   * choosen out of 0 to PROBE_WAIT seconds.
+   * compliant to RFC 3927 Section 2.2.1
+   */
+  autoip->ttw = (u16_t)(LWIP_AUTOIP_RAND(netif) % (PROBE_WAIT * AUTOIP_TICKS_PER_SECOND));
+
+  /*
+   * if we tried more then MAX_CONFLICTS we must limit our rate for
+   * accquiring and probing address
+   * compliant to RFC 3927 Section 2.2.1
+   */
+  if(autoip->tried_llipaddr > MAX_CONFLICTS) {
+    autoip->ttw = RATE_LIMIT_INTERVAL * AUTOIP_TICKS_PER_SECOND;
+  }
+}
+
+/**
+ * Handle a possible change in the network configuration.
+ *
+ * If there is an AutoIP address configured, take the interface down
+ * and begin probing with the same address.
+ */
+void
+autoip_network_changed(struct netif *netif)
+{
+  if (netif->autoip && netif->autoip->state != AUTOIP_STATE_OFF) {
+    netif_set_down(netif);
+    autoip_start_probing(netif);
+  }
+}
+
+/**
+ * Stop AutoIP client
+ *
+ * @param netif network interface on which stop the AutoIP client
+ */
+err_t
+autoip_stop(struct netif *netif)
+{
+  netif->autoip->state = AUTOIP_STATE_OFF;
+  netif_set_down(netif);
+  return ERR_OK;
+}
+
+/**
+ * Has to be called in loop every AUTOIP_TMR_INTERVAL milliseconds
+ */
+void
+autoip_tmr()
+{
+  struct netif *netif = netif_list;
+  /* loop through netif's */
+  while (netif != NULL) {
+    /* only act on AutoIP configured interfaces */
+    if (netif->autoip != NULL) {
+      if(netif->autoip->lastconflict > 0) {
+        netif->autoip->lastconflict--;
+      }
+
+      LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
+        ("autoip_tmr() AutoIP-State: %"U16_F", ttw=%"U16_F"\n",
+        (u16_t)(netif->autoip->state), netif->autoip->ttw));
+
+      switch(netif->autoip->state) {
+        case AUTOIP_STATE_PROBING:
+          if(netif->autoip->ttw > 0) {
+            netif->autoip->ttw--;
+          } else {
+            if(netif->autoip->sent_num >= PROBE_NUM) {
+              netif->autoip->state = AUTOIP_STATE_ANNOUNCING;
+              netif->autoip->sent_num = 0;
+              netif->autoip->ttw = ANNOUNCE_WAIT * AUTOIP_TICKS_PER_SECOND;
+              LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
+                 ("autoip_tmr(): changing state to ANNOUNCING: %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
+                  ip4_addr1_16(&netif->autoip->llipaddr), ip4_addr2_16(&netif->autoip->llipaddr),
+                  ip4_addr3_16(&netif->autoip->llipaddr), ip4_addr4_16(&netif->autoip->llipaddr)));
+            } else {
+              autoip_arp_probe(netif);
+              LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
+                ("autoip_tmr() PROBING Sent Probe\n"));
+              netif->autoip->sent_num++;
+              /* calculate time to wait to next probe */
+              netif->autoip->ttw = (u16_t)((LWIP_AUTOIP_RAND(netif) %
+                ((PROBE_MAX - PROBE_MIN) * AUTOIP_TICKS_PER_SECOND) ) +
+                PROBE_MIN * AUTOIP_TICKS_PER_SECOND);
+            }
+          }
+          break;
+
+        case AUTOIP_STATE_ANNOUNCING:
+          if(netif->autoip->ttw > 0) {
+            netif->autoip->ttw--;
+          } else {
+            if(netif->autoip->sent_num == 0) {
+             /* We are here the first time, so we waited ANNOUNCE_WAIT seconds
+              * Now we can bind to an IP address and use it.
+              *
+              * autoip_bind calls netif_set_up. This triggers a gratuitous ARP
+              * which counts as an announcement.
+              */
+              autoip_bind(netif);
+            } else {
+              autoip_arp_announce(netif);
+              LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
+                ("autoip_tmr() ANNOUNCING Sent Announce\n"));
+            }
+            netif->autoip->ttw = ANNOUNCE_INTERVAL * AUTOIP_TICKS_PER_SECOND;
+            netif->autoip->sent_num++;
+
+            if(netif->autoip->sent_num >= ANNOUNCE_NUM) {
+                netif->autoip->state = AUTOIP_STATE_BOUND;
+                netif->autoip->sent_num = 0;
+                netif->autoip->ttw = 0;
+                 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
+                    ("autoip_tmr(): changing state to BOUND: %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
+                     ip4_addr1_16(&netif->autoip->llipaddr), ip4_addr2_16(&netif->autoip->llipaddr),
+                     ip4_addr3_16(&netif->autoip->llipaddr), ip4_addr4_16(&netif->autoip->llipaddr)));
+            }
+          }
+          break;
+      }
+    }
+    /* proceed to next network interface */
+    netif = netif->next;
+  }
+}
+
+/**
+ * Handles every incoming ARP Packet, called by etharp_arp_input.
+ *
+ * @param netif network interface to use for autoip processing
+ * @param hdr Incoming ARP packet
+ */
+void
+autoip_arp_reply(struct netif *netif, struct etharp_hdr *hdr)
+{
+  LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, ("autoip_arp_reply()\n"));
+  if ((netif->autoip != NULL) && (netif->autoip->state != AUTOIP_STATE_OFF)) {
+   /* when ip.src == llipaddr && hw.src != netif->hwaddr
+    *
+    * when probing  ip.dst == llipaddr && hw.src != netif->hwaddr
+    * we have a conflict and must solve it
+    */
+    ip_addr_t sipaddr, dipaddr;
+    struct eth_addr netifaddr;
+    netifaddr.addr[0] = netif->hwaddr[0];
+    netifaddr.addr[1] = netif->hwaddr[1];
+    netifaddr.addr[2] = netif->hwaddr[2];
+    netifaddr.addr[3] = netif->hwaddr[3];
+    netifaddr.addr[4] = netif->hwaddr[4];
+    netifaddr.addr[5] = netif->hwaddr[5];
+
+    /* Copy struct ip_addr2 to aligned ip_addr, to support compilers without
+     * structure packing (not using structure copy which breaks strict-aliasing rules).
+     */
+    IPADDR2_COPY(&sipaddr, &hdr->sipaddr);
+    IPADDR2_COPY(&dipaddr, &hdr->dipaddr);
+      
+    if ((netif->autoip->state == AUTOIP_STATE_PROBING) ||
+        ((netif->autoip->state == AUTOIP_STATE_ANNOUNCING) &&
+         (netif->autoip->sent_num == 0))) {
+     /* RFC 3927 Section 2.2.1:
+      * from beginning to after ANNOUNCE_WAIT
+      * seconds we have a conflict if
+      * ip.src == llipaddr OR
+      * ip.dst == llipaddr && hw.src != own hwaddr
+      */
+      if ((ip_addr_cmp(&sipaddr, &netif->autoip->llipaddr)) ||
+          (ip_addr_cmp(&dipaddr, &netif->autoip->llipaddr) &&
+           !eth_addr_cmp(&netifaddr, &hdr->shwaddr))) {
+        LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | LWIP_DBG_LEVEL_WARNING,
+          ("autoip_arp_reply(): Probe Conflict detected\n"));
+        autoip_restart(netif);
+      }
+    } else {
+     /* RFC 3927 Section 2.5:
+      * in any state we have a conflict if
+      * ip.src == llipaddr && hw.src != own hwaddr
+      */
+      if (ip_addr_cmp(&sipaddr, &netif->autoip->llipaddr) &&
+          !eth_addr_cmp(&netifaddr, &hdr->shwaddr)) {
+        LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | LWIP_DBG_LEVEL_WARNING,
+          ("autoip_arp_reply(): Conflicting ARP-Packet detected\n"));
+        autoip_handle_arp_conflict(netif);
+      }
+    }
+  }
+}
+
+#endif /* LWIP_AUTOIP */