autoip.c

00001 /**
00002  * @file
00003  * AutoIP Automatic LinkLocal IP Configuration
00004  *
00005  */
00006 
00007 /*
00008  *
00009  * Copyright (c) 2007 Dominik Spies <kontakt@dspies.de>
00010  * All rights reserved.
00011  *
00012  * Redistribution and use in source and binary forms, with or without modification,
00013  * are permitted provided that the following conditions are met:
00014  *
00015  * 1. Redistributions of source code must retain the above copyright notice,
00016  *    this list of conditions and the following disclaimer.
00017  * 2. Redistributions in binary form must reproduce the above copyright notice,
00018  *    this list of conditions and the following disclaimer in the documentation
00019  *    and/or other materials provided with the distribution.
00020  * 3. The name of the author may not be used to endorse or promote products
00021  *    derived from this software without specific prior written permission.
00022  *
00023  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
00024  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
00025  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
00026  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
00027  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
00028  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
00029  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
00030  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
00031  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
00032  * OF SUCH DAMAGE.
00033  *
00034  * Author: Dominik Spies <kontakt@dspies.de>
00035  *
00036  * This is a AutoIP implementation for the lwIP TCP/IP stack. It aims to conform
00037  * with RFC 3927.
00038  *
00039  *
00040  * Please coordinate changes and requests with Dominik Spies
00041  * <kontakt@dspies.de>
00042  */
00043 
00044 /*******************************************************************************
00045  * USAGE:
00046  * 
00047  * define LWIP_AUTOIP 1  in your lwipopts.h
00048  * 
00049  * If you don't use tcpip.c (so, don't call, you don't call tcpip_init):
00050  * - First, call autoip_init().
00051  * - call autoip_tmr() all AUTOIP_TMR_INTERVAL msces,
00052  *   that should be defined in autoip.h.
00053  *   I recommend a value of 100. The value must divide 1000 with a remainder almost 0.
00054  *   Possible values are 1000, 500, 333, 250, 200, 166, 142, 125, 111, 100 ....
00055  *
00056  * Without DHCP:
00057  * - Call autoip_start() after netif_add().
00058  * 
00059  * With DHCP:
00060  * - define LWIP_DHCP_AUTOIP_COOP 1 in your lwipopts.h.
00061  * - Configure your DHCP Client.
00062  *
00063  */
00064 
00065 #include "lwip/opt.h"
00066 
00067 #if LWIP_AUTOIP /* don't build if not configured for use in lwipopts.h */
00068 
00069 #include "lwip/mem.h"
00070 #include "lwip/udp.h"
00071 #include "lwip/ip_addr.h"
00072 #include "lwip/netif.h"
00073 #include "lwip/autoip.h"
00074 #include "netif/etharp.h"
00075 
00076 #include <stdlib.h>
00077 #include <string.h>
00078 
00079 /* 169.254.0.0 */
00080 #define AUTOIP_NET         0xA9FE0000
00081 /* 169.254.1.0 */
00082 #define AUTOIP_RANGE_START (AUTOIP_NET | 0x0100)
00083 /* 169.254.254.255 */
00084 #define AUTOIP_RANGE_END   (AUTOIP_NET | 0xFEFF)
00085 
00086 
00087 /** Pseudo random macro based on netif informations.
00088  * You could use "rand()" from the C Library if you define LWIP_AUTOIP_RAND in lwipopts.h */
00089 #ifndef LWIP_AUTOIP_RAND
00090 #define LWIP_AUTOIP_RAND(netif) ( (((u32_t)((netif->hwaddr[5]) & 0xff) << 24) | \
00091                                    ((u32_t)((netif->hwaddr[3]) & 0xff) << 16) | \
00092                                    ((u32_t)((netif->hwaddr[2]) & 0xff) << 8) | \
00093                                    ((u32_t)((netif->hwaddr[4]) & 0xff))) + \
00094                                    (netif->autoip?netif->autoip->tried_llipaddr:0))
00095 #endif /* LWIP_AUTOIP_RAND */
00096 
00097 /**
00098  * Macro that generates the initial IP address to be tried by AUTOIP.
00099  * If you want to override this, define it to something else in lwipopts.h.
00100  */
00101 #ifndef LWIP_AUTOIP_CREATE_SEED_ADDR
00102 #define LWIP_AUTOIP_CREATE_SEED_ADDR(netif) \
00103   htonl(AUTOIP_RANGE_START + ((u32_t)(((u8_t)(netif->hwaddr[4])) | \
00104                  ((u32_t)((u8_t)(netif->hwaddr[5]))) << 8)))
00105 #endif /* LWIP_AUTOIP_CREATE_SEED_ADDR */
00106 
00107 /* static functions */
00108 static void autoip_handle_arp_conflict(struct netif *netif);
00109 
00110 /* creates a pseudo random LL IP-Address for a network interface */
00111 static void autoip_create_addr(struct netif *netif, ip_addr_t *ipaddr);
00112 
00113 /* sends an ARP probe */
00114 static err_t autoip_arp_probe(struct netif *netif);
00115 
00116 /* sends an ARP announce */
00117 static err_t autoip_arp_announce(struct netif *netif);
00118 
00119 /* configure interface for use with current LL IP-Address */
00120 static err_t autoip_bind(struct netif *netif);
00121 
00122 /* start sending probes for llipaddr */
00123 static void autoip_start_probing(struct netif *netif);
00124 
00125 
00126 /** Set a statically allocated struct autoip to work with.
00127  * Using this prevents autoip_start to allocate it using mem_malloc.
00128  *
00129  * @param netif the netif for which to set the struct autoip
00130  * @param dhcp (uninitialised) dhcp struct allocated by the application
00131  */
00132 void
00133 autoip_set_struct(struct netif *netif, struct autoip *autoip)
00134 {
00135   LWIP_ASSERT("netif != NULL", netif != NULL);
00136   LWIP_ASSERT("autoip != NULL", autoip != NULL);
00137   LWIP_ASSERT("netif already has a struct autoip set", netif->autoip == NULL);
00138 
00139   /* clear data structure */
00140   memset(autoip, 0, sizeof(struct autoip));
00141   /* autoip->state = AUTOIP_STATE_OFF; */
00142   netif->autoip = autoip;
00143 }
00144 
00145 /** Restart AutoIP client and check the next address (conflict detected)
00146  *
00147  * @param netif The netif under AutoIP control
00148  */
00149 static void
00150 autoip_restart(struct netif *netif)
00151 {
00152   netif->autoip->tried_llipaddr++;
00153   autoip_start(netif);
00154 }
00155 
00156 /**
00157  * Handle a IP address conflict after an ARP conflict detection
00158  */
00159 static void
00160 autoip_handle_arp_conflict(struct netif *netif)
00161 {
00162   /* Somehow detect if we are defending or retreating */
00163   unsigned char defend = 1; /* tbd */
00164 
00165   if (defend) {
00166     if (netif->autoip->lastconflict > 0) {
00167       /* retreat, there was a conflicting ARP in the last
00168        * DEFEND_INTERVAL seconds
00169        */
00170       LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
00171         ("autoip_handle_arp_conflict(): we are defending, but in DEFEND_INTERVAL, retreating\n"));
00172 
00173       /* TODO: close all TCP sessions */
00174       autoip_restart(netif);
00175     } else {
00176       LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
00177         ("autoip_handle_arp_conflict(): we are defend, send ARP Announce\n"));
00178       autoip_arp_announce(netif);
00179       netif->autoip->lastconflict = DEFEND_INTERVAL * AUTOIP_TICKS_PER_SECOND;
00180     }
00181   } else {
00182     LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
00183       ("autoip_handle_arp_conflict(): we do not defend, retreating\n"));
00184     /* TODO: close all TCP sessions */
00185     autoip_restart(netif);
00186   }
00187 }
00188 
00189 /**
00190  * Create an IP-Address out of range 169.254.1.0 to 169.254.254.255
00191  *
00192  * @param netif network interface on which create the IP-Address
00193  * @param ipaddr ip address to initialize
00194  */
00195 static void
00196 autoip_create_addr(struct netif *netif, ip_addr_t *ipaddr)
00197 {
00198   /* Here we create an IP-Address out of range 169.254.1.0 to 169.254.254.255
00199    * compliant to RFC 3927 Section 2.1
00200    * We have 254 * 256 possibilities */
00201 
00202   u32_t addr = ntohl(LWIP_AUTOIP_CREATE_SEED_ADDR(netif));
00203   addr += netif->autoip->tried_llipaddr;
00204   addr = AUTOIP_NET | (addr & 0xffff);
00205   /* Now, 169.254.0.0 <= addr <= 169.254.255.255 */ 
00206 
00207   if (addr < AUTOIP_RANGE_START) {
00208     addr += AUTOIP_RANGE_END - AUTOIP_RANGE_START + 1;
00209   }
00210   if (addr > AUTOIP_RANGE_END) {
00211     addr -= AUTOIP_RANGE_END - AUTOIP_RANGE_START + 1;
00212   }
00213   LWIP_ASSERT("AUTOIP address not in range", (addr >= AUTOIP_RANGE_START) &&
00214     (addr <= AUTOIP_RANGE_END));
00215   ip4_addr_set_u32(ipaddr, htonl(addr));
00216   
00217   LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
00218     ("autoip_create_addr(): tried_llipaddr=%"U16_F", %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
00219     (u16_t)(netif->autoip->tried_llipaddr), ip4_addr1_16(ipaddr), ip4_addr2_16(ipaddr),
00220     ip4_addr3_16(ipaddr), ip4_addr4_16(ipaddr)));
00221 }
00222 
00223 /**
00224  * Sends an ARP probe from a network interface
00225  *
00226  * @param netif network interface used to send the probe
00227  */
00228 static err_t
00229 autoip_arp_probe(struct netif *netif)
00230 {
00231   return etharp_raw(netif, (struct eth_addr *)netif->hwaddr, &ethbroadcast,
00232     (struct eth_addr *)netif->hwaddr, IP_ADDR_ANY, &ethzero,
00233     &netif->autoip->llipaddr, ARP_REQUEST);
00234 }
00235 
00236 /**
00237  * Sends an ARP announce from a network interface
00238  *
00239  * @param netif network interface used to send the announce
00240  */
00241 static err_t
00242 autoip_arp_announce(struct netif *netif)
00243 {
00244   return etharp_raw(netif, (struct eth_addr *)netif->hwaddr, &ethbroadcast,
00245     (struct eth_addr *)netif->hwaddr, &netif->autoip->llipaddr, &ethzero,
00246     &netif->autoip->llipaddr, ARP_REQUEST);
00247 }
00248 
00249 /**
00250  * Configure interface for use with current LL IP-Address
00251  *
00252  * @param netif network interface to configure with current LL IP-Address
00253  */
00254 static err_t
00255 autoip_bind(struct netif *netif)
00256 {
00257   struct autoip *autoip = netif->autoip;
00258   ip_addr_t sn_mask, gw_addr;
00259 
00260   LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
00261     ("autoip_bind(netif=%p) %c%c%"U16_F" %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
00262     (void*)netif, netif->name[0], netif->name[1], (u16_t)netif->num,
00263     ip4_addr1_16(&autoip->llipaddr), ip4_addr2_16(&autoip->llipaddr),
00264     ip4_addr3_16(&autoip->llipaddr), ip4_addr4_16(&autoip->llipaddr)));
00265 
00266   IP4_ADDR(&sn_mask, 255, 255, 0, 0);
00267   IP4_ADDR(&gw_addr, 0, 0, 0, 0);
00268 
00269   netif_set_ipaddr(netif, &autoip->llipaddr);
00270   netif_set_netmask(netif, &sn_mask);
00271   netif_set_gw(netif, &gw_addr);  
00272 
00273   /* bring the interface up */
00274   netif_set_up(netif);
00275 
00276   return ERR_OK;
00277 }
00278 
00279 /**
00280  * Start AutoIP client
00281  *
00282  * @param netif network interface on which start the AutoIP client
00283  */
00284 err_t
00285 autoip_start(struct netif *netif)
00286 {
00287   struct autoip *autoip = netif->autoip;
00288   err_t result = ERR_OK;
00289 
00290   if (netif_is_up(netif)) {
00291     netif_set_down(netif);
00292   }
00293 
00294   /* Set IP-Address, Netmask and Gateway to 0 to make sure that
00295    * ARP Packets are formed correctly
00296    */
00297   ip_addr_set_zero(&netif->ip_addr);
00298   ip_addr_set_zero(&netif->netmask);
00299   ip_addr_set_zero(&netif->gw);
00300 
00301   LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
00302     ("autoip_start(netif=%p) %c%c%"U16_F"\n", (void*)netif, netif->name[0],
00303     netif->name[1], (u16_t)netif->num));
00304   if (autoip == NULL) {
00305     /* no AutoIP client attached yet? */
00306     LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
00307       ("autoip_start(): starting new AUTOIP client\n"));
00308     autoip = (struct autoip *)mem_malloc(sizeof(struct autoip));
00309     if (autoip == NULL) {
00310       LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
00311         ("autoip_start(): could not allocate autoip\n"));
00312       return ERR_MEM;
00313     }
00314     memset(autoip, 0, sizeof(struct autoip));
00315     /* store this AutoIP client in the netif */
00316     netif->autoip = autoip;
00317     LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, ("autoip_start(): allocated autoip"));
00318   } else {
00319     autoip->state = AUTOIP_STATE_OFF;
00320     autoip->ttw = 0;
00321     autoip->sent_num = 0;
00322     ip_addr_set_zero(&autoip->llipaddr);
00323     autoip->lastconflict = 0;
00324   }
00325 
00326   autoip_create_addr(netif, &(autoip->llipaddr));
00327   autoip_start_probing(netif);
00328 
00329   return result;
00330 }
00331 
00332 static void
00333 autoip_start_probing(struct netif *netif)
00334 {
00335   struct autoip *autoip = netif->autoip;
00336 
00337   autoip->state = AUTOIP_STATE_PROBING;
00338   autoip->sent_num = 0;
00339   LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
00340      ("autoip_start_probing(): changing state to PROBING: %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
00341       ip4_addr1_16(&netif->autoip->llipaddr), ip4_addr2_16(&netif->autoip->llipaddr),
00342       ip4_addr3_16(&netif->autoip->llipaddr), ip4_addr4_16(&netif->autoip->llipaddr)));
00343 
00344   /* time to wait to first probe, this is randomly
00345    * choosen out of 0 to PROBE_WAIT seconds.
00346    * compliant to RFC 3927 Section 2.2.1
00347    */
00348   autoip->ttw = (u16_t)(LWIP_AUTOIP_RAND(netif) % (PROBE_WAIT * AUTOIP_TICKS_PER_SECOND));
00349 
00350   /*
00351    * if we tried more then MAX_CONFLICTS we must limit our rate for
00352    * accquiring and probing address
00353    * compliant to RFC 3927 Section 2.2.1
00354    */
00355   if (autoip->tried_llipaddr > MAX_CONFLICTS) {
00356     autoip->ttw = RATE_LIMIT_INTERVAL * AUTOIP_TICKS_PER_SECOND;
00357   }
00358 }
00359 
00360 /**
00361  * Handle a possible change in the network configuration.
00362  *
00363  * If there is an AutoIP address configured, take the interface down
00364  * and begin probing with the same address.
00365  */
00366 void
00367 autoip_network_changed(struct netif *netif)
00368 {
00369   if (netif->autoip && netif->autoip->state != AUTOIP_STATE_OFF) {
00370     netif_set_down(netif);
00371     autoip_start_probing(netif);
00372   }
00373 }
00374 
00375 /**
00376  * Stop AutoIP client
00377  *
00378  * @param netif network interface on which stop the AutoIP client
00379  */
00380 err_t
00381 autoip_stop(struct netif *netif)
00382 {
00383   netif->autoip->state = AUTOIP_STATE_OFF;
00384   netif_set_down(netif);
00385   return ERR_OK;
00386 }
00387 
00388 /**
00389  * Has to be called in loop every AUTOIP_TMR_INTERVAL milliseconds
00390  */
00391 void
00392 autoip_tmr()
00393 {
00394   struct netif *netif = netif_list;
00395   /* loop through netif's */
00396   while (netif != NULL) {
00397     /* only act on AutoIP configured interfaces */
00398     if (netif->autoip != NULL) {
00399       if (netif->autoip->lastconflict > 0) {
00400         netif->autoip->lastconflict--;
00401       }
00402 
00403       LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
00404         ("autoip_tmr() AutoIP-State: %"U16_F", ttw=%"U16_F"\n",
00405         (u16_t)(netif->autoip->state), netif->autoip->ttw));
00406 
00407       switch(netif->autoip->state) {
00408         case AUTOIP_STATE_PROBING:
00409           if (netif->autoip->ttw > 0) {
00410             netif->autoip->ttw--;
00411           } else {
00412             if (netif->autoip->sent_num >= PROBE_NUM) {
00413               netif->autoip->state = AUTOIP_STATE_ANNOUNCING;
00414               netif->autoip->sent_num = 0;
00415               netif->autoip->ttw = ANNOUNCE_WAIT * AUTOIP_TICKS_PER_SECOND;
00416               LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
00417                  ("autoip_tmr(): changing state to ANNOUNCING: %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
00418                   ip4_addr1_16(&netif->autoip->llipaddr), ip4_addr2_16(&netif->autoip->llipaddr),
00419                   ip4_addr3_16(&netif->autoip->llipaddr), ip4_addr4_16(&netif->autoip->llipaddr)));
00420             } else {
00421               autoip_arp_probe(netif);
00422               LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
00423                 ("autoip_tmr() PROBING Sent Probe\n"));
00424               netif->autoip->sent_num++;
00425               /* calculate time to wait to next probe */
00426               netif->autoip->ttw = (u16_t)((LWIP_AUTOIP_RAND(netif) %
00427                 ((PROBE_MAX - PROBE_MIN) * AUTOIP_TICKS_PER_SECOND) ) +
00428                 PROBE_MIN * AUTOIP_TICKS_PER_SECOND);
00429             }
00430           }
00431           break;
00432 
00433         case AUTOIP_STATE_ANNOUNCING:
00434           if (netif->autoip->ttw > 0) {
00435             netif->autoip->ttw--;
00436           } else {
00437             if (netif->autoip->sent_num == 0) {
00438              /* We are here the first time, so we waited ANNOUNCE_WAIT seconds
00439               * Now we can bind to an IP address and use it.
00440               *
00441               * autoip_bind calls netif_set_up. This triggers a gratuitous ARP
00442               * which counts as an announcement.
00443               */
00444               autoip_bind(netif);
00445             } else {
00446               autoip_arp_announce(netif);
00447               LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
00448                 ("autoip_tmr() ANNOUNCING Sent Announce\n"));
00449             }
00450             netif->autoip->ttw = ANNOUNCE_INTERVAL * AUTOIP_TICKS_PER_SECOND;
00451             netif->autoip->sent_num++;
00452 
00453             if (netif->autoip->sent_num >= ANNOUNCE_NUM) {
00454                 netif->autoip->state = AUTOIP_STATE_BOUND;
00455                 netif->autoip->sent_num = 0;
00456                 netif->autoip->ttw = 0;
00457                  LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
00458                     ("autoip_tmr(): changing state to BOUND: %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
00459                      ip4_addr1_16(&netif->autoip->llipaddr), ip4_addr2_16(&netif->autoip->llipaddr),
00460                      ip4_addr3_16(&netif->autoip->llipaddr), ip4_addr4_16(&netif->autoip->llipaddr)));
00461             }
00462           }
00463           break;
00464       }
00465     }
00466     /* proceed to next network interface */
00467     netif = netif->next;
00468   }
00469 }
00470 
00471 /**
00472  * Handles every incoming ARP Packet, called by etharp_arp_input.
00473  *
00474  * @param netif network interface to use for autoip processing
00475  * @param hdr Incoming ARP packet
00476  */
00477 void
00478 autoip_arp_reply(struct netif *netif, struct etharp_hdr *hdr)
00479 {
00480   LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, ("autoip_arp_reply()\n"));
00481   if ((netif->autoip != NULL) && (netif->autoip->state != AUTOIP_STATE_OFF)) {
00482    /* when ip.src == llipaddr && hw.src != netif->hwaddr
00483     *
00484     * when probing  ip.dst == llipaddr && hw.src != netif->hwaddr
00485     * we have a conflict and must solve it
00486     */
00487     ip_addr_t sipaddr, dipaddr;
00488     struct eth_addr netifaddr;
00489     ETHADDR16_COPY(netifaddr.addr, netif->hwaddr);
00490 
00491     /* Copy struct ip_addr2 to aligned ip_addr, to support compilers without
00492      * structure packing (not using structure copy which breaks strict-aliasing rules).
00493      */
00494     IPADDR2_COPY(&sipaddr, &hdr->sipaddr);
00495     IPADDR2_COPY(&dipaddr, &hdr->dipaddr);
00496       
00497     if ((netif->autoip->state == AUTOIP_STATE_PROBING) ||
00498         ((netif->autoip->state == AUTOIP_STATE_ANNOUNCING) &&
00499          (netif->autoip->sent_num == 0))) {
00500      /* RFC 3927 Section 2.2.1:
00501       * from beginning to after ANNOUNCE_WAIT
00502       * seconds we have a conflict if
00503       * ip.src == llipaddr OR
00504       * ip.dst == llipaddr && hw.src != own hwaddr
00505       */
00506       if ((ip_addr_cmp(&sipaddr, &netif->autoip->llipaddr)) ||
00507           (ip_addr_cmp(&dipaddr, &netif->autoip->llipaddr) &&
00508            !eth_addr_cmp(&netifaddr, &hdr->shwaddr))) {
00509         LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | LWIP_DBG_LEVEL_WARNING,
00510           ("autoip_arp_reply(): Probe Conflict detected\n"));
00511         autoip_restart(netif);
00512       }
00513     } else {
00514      /* RFC 3927 Section 2.5:
00515       * in any state we have a conflict if
00516       * ip.src == llipaddr && hw.src != own hwaddr
00517       */
00518       if (ip_addr_cmp(&sipaddr, &netif->autoip->llipaddr) &&
00519           !eth_addr_cmp(&netifaddr, &hdr->shwaddr)) {
00520         LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | LWIP_DBG_LEVEL_WARNING,
00521           ("autoip_arp_reply(): Conflicting ARP-Packet detected\n"));
00522         autoip_handle_arp_conflict(netif);
00523       }
00524     }
00525   }
00526 }
00527 
00528 #endif /* LWIP_AUTOIP */