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  * Initialize this module
00127  */
00128 void
00129 autoip_init(void)
00130 {
00131   LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, ("autoip_init()\n"));
00132 }
00133 
00134 /** Set a statically allocated struct autoip to work with.
00135  * Using this prevents autoip_start to allocate it using mem_malloc.
00136  *
00137  * @param netif the netif for which to set the struct autoip
00138  * @param dhcp (uninitialised) dhcp struct allocated by the application
00139  */
00140 void
00141 autoip_set_struct(struct netif *netif, struct autoip *autoip)
00142 {
00143   LWIP_ASSERT("netif != NULL", netif != NULL);
00144   LWIP_ASSERT("autoip != NULL", autoip != NULL);
00145   LWIP_ASSERT("netif already has a struct autoip set", netif->autoip == NULL);
00146 
00147   /* clear data structure */
00148   memset(autoip, 0, sizeof(struct autoip));
00149   /* autoip->state = AUTOIP_STATE_OFF; */
00150   netif->autoip = autoip;
00151 }
00152 
00153 /**
00154  * Handle a IP address conflict after an ARP conflict detection
00155  */
00156 static void
00157 autoip_handle_arp_conflict(struct netif *netif)
00158 {
00159   /* Somehow detect if we are defending or retreating */
00160   unsigned char defend = 1; /* tbd */
00161 
00162   if(defend) {
00163     if(netif->autoip->lastconflict > 0) {
00164       /* retreat, there was a conflicting ARP in the last
00165        * DEFEND_INTERVAL seconds
00166        */
00167       LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
00168         ("autoip_handle_arp_conflict(): we are defending, but in DEFEND_INTERVAL, retreating\n"));
00169 
00170       /* TODO: close all TCP sessions */
00171       autoip_start(netif);
00172     } else {
00173       LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
00174         ("autoip_handle_arp_conflict(): we are defend, send ARP Announce\n"));
00175       autoip_arp_announce(netif);
00176       netif->autoip->lastconflict = DEFEND_INTERVAL * AUTOIP_TICKS_PER_SECOND;
00177     }
00178   } else {
00179     LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
00180       ("autoip_handle_arp_conflict(): we do not defend, retreating\n"));
00181     /* TODO: close all TCP sessions */
00182     autoip_start(netif);
00183   }
00184 }
00185 
00186 /**
00187  * Create an IP-Address out of range 169.254.1.0 to 169.254.254.255
00188  *
00189  * @param netif network interface on which create the IP-Address
00190  * @param ipaddr ip address to initialize
00191  */
00192 static void
00193 autoip_create_addr(struct netif *netif, ip_addr_t *ipaddr)
00194 {
00195   /* Here we create an IP-Address out of range 169.254.1.0 to 169.254.254.255
00196    * compliant to RFC 3927 Section 2.1
00197    * We have 254 * 256 possibilities */
00198 
00199   u32_t addr = ntohl(LWIP_AUTOIP_CREATE_SEED_ADDR(netif));
00200   addr += netif->autoip->tried_llipaddr;
00201   addr = AUTOIP_NET | (addr & 0xffff);
00202   /* Now, 169.254.0.0 <= addr <= 169.254.255.255 */ 
00203 
00204   if (addr < AUTOIP_RANGE_START) {
00205     addr += AUTOIP_RANGE_END - AUTOIP_RANGE_START + 1;
00206   }
00207   if (addr > AUTOIP_RANGE_END) {
00208     addr -= AUTOIP_RANGE_END - AUTOIP_RANGE_START + 1;
00209   }
00210   LWIP_ASSERT("AUTOIP address not in range", (addr >= AUTOIP_RANGE_START) &&
00211     (addr <= AUTOIP_RANGE_END));
00212   ip4_addr_set_u32(ipaddr, htonl(addr));
00213   
00214   LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
00215     ("autoip_create_addr(): tried_llipaddr=%"U16_F", %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
00216     (u16_t)(netif->autoip->tried_llipaddr), ip4_addr1_16(ipaddr), ip4_addr2_16(ipaddr),
00217     ip4_addr3_16(ipaddr), ip4_addr4_16(ipaddr)));
00218 }
00219 
00220 /**
00221  * Sends an ARP probe from a network interface
00222  *
00223  * @param netif network interface used to send the probe
00224  */
00225 static err_t
00226 autoip_arp_probe(struct netif *netif)
00227 {
00228   return etharp_raw(netif, (struct eth_addr *)netif->hwaddr, &ethbroadcast,
00229     (struct eth_addr *)netif->hwaddr, IP_ADDR_ANY, &ethzero,
00230     &netif->autoip->llipaddr, ARP_REQUEST);
00231 }
00232 
00233 /**
00234  * Sends an ARP announce from a network interface
00235  *
00236  * @param netif network interface used to send the announce
00237  */
00238 static err_t
00239 autoip_arp_announce(struct netif *netif)
00240 {
00241   return etharp_raw(netif, (struct eth_addr *)netif->hwaddr, &ethbroadcast,
00242     (struct eth_addr *)netif->hwaddr, &netif->autoip->llipaddr, &ethzero,
00243     &netif->autoip->llipaddr, ARP_REQUEST);
00244 }
00245 
00246 /**
00247  * Configure interface for use with current LL IP-Address
00248  *
00249  * @param netif network interface to configure with current LL IP-Address
00250  */
00251 static err_t
00252 autoip_bind(struct netif *netif)
00253 {
00254   struct autoip *autoip = netif->autoip;
00255   ip_addr_t sn_mask, gw_addr;
00256 
00257   LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
00258     ("autoip_bind(netif=%p) %c%c%"U16_F" %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
00259     (void*)netif, netif->name[0], netif->name[1], (u16_t)netif->num,
00260     ip4_addr1_16(&autoip->llipaddr), ip4_addr2_16(&autoip->llipaddr),
00261     ip4_addr3_16(&autoip->llipaddr), ip4_addr4_16(&autoip->llipaddr)));
00262 
00263   IP4_ADDR(&sn_mask, 255, 255, 0, 0);
00264   IP4_ADDR(&gw_addr, 0, 0, 0, 0);
00265 
00266   netif_set_ipaddr(netif, &autoip->llipaddr);
00267   netif_set_netmask(netif, &sn_mask);
00268   netif_set_gw(netif, &gw_addr);  
00269 
00270   /* bring the interface up */
00271   netif_set_up(netif);
00272 
00273   return ERR_OK;
00274 }
00275 
00276 /**
00277  * Start AutoIP client
00278  *
00279  * @param netif network interface on which start the AutoIP client
00280  */
00281 err_t
00282 autoip_start(struct netif *netif)
00283 {
00284   struct autoip *autoip = netif->autoip;
00285   err_t result = ERR_OK;
00286 
00287   if(netif_is_up(netif)) {
00288     netif_set_down(netif);
00289   }
00290 
00291   /* Set IP-Address, Netmask and Gateway to 0 to make sure that
00292    * ARP Packets are formed correctly
00293    */
00294   ip_addr_set_zero(&netif->ip_addr);
00295   ip_addr_set_zero(&netif->netmask);
00296   ip_addr_set_zero(&netif->gw);
00297 
00298   LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
00299     ("autoip_start(netif=%p) %c%c%"U16_F"\n", (void*)netif, netif->name[0],
00300     netif->name[1], (u16_t)netif->num));
00301   if(autoip == NULL) {
00302     /* no AutoIP client attached yet? */
00303     LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
00304       ("autoip_start(): starting new AUTOIP client\n"));
00305     autoip = (struct autoip *)mem_malloc(sizeof(struct autoip));
00306     if(autoip == NULL) {
00307       LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
00308         ("autoip_start(): could not allocate autoip\n"));
00309       return ERR_MEM;
00310     }
00311     memset( autoip, 0, sizeof(struct autoip));
00312     /* store this AutoIP client in the netif */
00313     netif->autoip = autoip;
00314     LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, ("autoip_start(): allocated autoip"));
00315   } else {
00316     autoip->state = AUTOIP_STATE_OFF;
00317     autoip->ttw = 0;
00318     autoip->sent_num = 0;
00319     memset(&autoip->llipaddr, 0, sizeof(ip_addr_t));
00320     autoip->lastconflict = 0;
00321   }
00322 
00323   autoip_create_addr(netif, &(autoip->llipaddr));
00324   autoip->tried_llipaddr++;
00325   autoip_start_probing(netif);
00326 
00327   return result;
00328 }
00329 
00330 static void
00331 autoip_start_probing(struct netif *netif)
00332 {
00333   struct autoip *autoip = netif->autoip;
00334 
00335   autoip->state = AUTOIP_STATE_PROBING;
00336   autoip->sent_num = 0;
00337   LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
00338      ("autoip_start_probing(): changing state to PROBING: %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
00339       ip4_addr1_16(&netif->autoip->llipaddr), ip4_addr2_16(&netif->autoip->llipaddr),
00340       ip4_addr3_16(&netif->autoip->llipaddr), ip4_addr4_16(&netif->autoip->llipaddr)));
00341 
00342   /* time to wait to first probe, this is randomly
00343    * choosen out of 0 to PROBE_WAIT seconds.
00344    * compliant to RFC 3927 Section 2.2.1
00345    */
00346   autoip->ttw = (u16_t)(LWIP_AUTOIP_RAND(netif) % (PROBE_WAIT * AUTOIP_TICKS_PER_SECOND));
00347 
00348   /*
00349    * if we tried more then MAX_CONFLICTS we must limit our rate for
00350    * accquiring and probing address
00351    * compliant to RFC 3927 Section 2.2.1
00352    */
00353   if(autoip->tried_llipaddr > MAX_CONFLICTS) {
00354     autoip->ttw = RATE_LIMIT_INTERVAL * AUTOIP_TICKS_PER_SECOND;
00355   }
00356 }
00357 
00358 /**
00359  * Handle a possible change in the network configuration.
00360  *
00361  * If there is an AutoIP address configured, take the interface down
00362  * and begin probing with the same address.
00363  */
00364 void
00365 autoip_network_changed(struct netif *netif)
00366 {
00367   if (netif->autoip && netif->autoip->state != AUTOIP_STATE_OFF) {
00368     netif_set_down(netif);
00369     autoip_start_probing(netif);
00370   }
00371 }
00372 
00373 /**
00374  * Stop AutoIP client
00375  *
00376  * @param netif network interface on which stop the AutoIP client
00377  */
00378 err_t
00379 autoip_stop(struct netif *netif)
00380 {
00381   netif->autoip->state = AUTOIP_STATE_OFF;
00382   netif_set_down(netif);
00383   return ERR_OK;
00384 }
00385 
00386 /**
00387  * Has to be called in loop every AUTOIP_TMR_INTERVAL milliseconds
00388  */
00389 void
00390 autoip_tmr()
00391 {
00392   struct netif *netif = netif_list;
00393   /* loop through netif's */
00394   while (netif != NULL) {
00395     /* only act on AutoIP configured interfaces */
00396     if (netif->autoip != NULL) {
00397       if(netif->autoip->lastconflict > 0) {
00398         netif->autoip->lastconflict--;
00399       }
00400 
00401       LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
00402         ("autoip_tmr() AutoIP-State: %"U16_F", ttw=%"U16_F"\n",
00403         (u16_t)(netif->autoip->state), netif->autoip->ttw));
00404 
00405       switch(netif->autoip->state) {
00406         case AUTOIP_STATE_PROBING:
00407           if(netif->autoip->ttw > 0) {
00408             netif->autoip->ttw--;
00409           } else {
00410             if(netif->autoip->sent_num >= PROBE_NUM) {
00411               netif->autoip->state = AUTOIP_STATE_ANNOUNCING;
00412               netif->autoip->sent_num = 0;
00413               netif->autoip->ttw = ANNOUNCE_WAIT * AUTOIP_TICKS_PER_SECOND;
00414               LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
00415                  ("autoip_tmr(): changing state to ANNOUNCING: %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
00416                   ip4_addr1_16(&netif->autoip->llipaddr), ip4_addr2_16(&netif->autoip->llipaddr),
00417                   ip4_addr3_16(&netif->autoip->llipaddr), ip4_addr4_16(&netif->autoip->llipaddr)));
00418             } else {
00419               autoip_arp_probe(netif);
00420               LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
00421                 ("autoip_tmr() PROBING Sent Probe\n"));
00422               netif->autoip->sent_num++;
00423               /* calculate time to wait to next probe */
00424               netif->autoip->ttw = (u16_t)((LWIP_AUTOIP_RAND(netif) %
00425                 ((PROBE_MAX - PROBE_MIN) * AUTOIP_TICKS_PER_SECOND) ) +
00426                 PROBE_MIN * AUTOIP_TICKS_PER_SECOND);
00427             }
00428           }
00429           break;
00430 
00431         case AUTOIP_STATE_ANNOUNCING:
00432           if(netif->autoip->ttw > 0) {
00433             netif->autoip->ttw--;
00434           } else {
00435             if(netif->autoip->sent_num == 0) {
00436              /* We are here the first time, so we waited ANNOUNCE_WAIT seconds
00437               * Now we can bind to an IP address and use it.
00438               *
00439               * autoip_bind calls netif_set_up. This triggers a gratuitous ARP
00440               * which counts as an announcement.
00441               */
00442               autoip_bind(netif);
00443             } else {
00444               autoip_arp_announce(netif);
00445               LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
00446                 ("autoip_tmr() ANNOUNCING Sent Announce\n"));
00447             }
00448             netif->autoip->ttw = ANNOUNCE_INTERVAL * AUTOIP_TICKS_PER_SECOND;
00449             netif->autoip->sent_num++;
00450 
00451             if(netif->autoip->sent_num >= ANNOUNCE_NUM) {
00452                 netif->autoip->state = AUTOIP_STATE_BOUND;
00453                 netif->autoip->sent_num = 0;
00454                 netif->autoip->ttw = 0;
00455                  LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
00456                     ("autoip_tmr(): changing state to BOUND: %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
00457                      ip4_addr1_16(&netif->autoip->llipaddr), ip4_addr2_16(&netif->autoip->llipaddr),
00458                      ip4_addr3_16(&netif->autoip->llipaddr), ip4_addr4_16(&netif->autoip->llipaddr)));
00459             }
00460           }
00461           break;
00462       }
00463     }
00464     /* proceed to next network interface */
00465     netif = netif->next;
00466   }
00467 }
00468 
00469 /**
00470  * Handles every incoming ARP Packet, called by etharp_arp_input.
00471  *
00472  * @param netif network interface to use for autoip processing
00473  * @param hdr Incoming ARP packet
00474  */
00475 void
00476 autoip_arp_reply(struct netif *netif, struct etharp_hdr *hdr)
00477 {
00478   LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, ("autoip_arp_reply()\n"));
00479   if ((netif->autoip != NULL) && (netif->autoip->state != AUTOIP_STATE_OFF)) {
00480    /* when ip.src == llipaddr && hw.src != netif->hwaddr
00481     *
00482     * when probing  ip.dst == llipaddr && hw.src != netif->hwaddr
00483     * we have a conflict and must solve it
00484     */
00485     ip_addr_t sipaddr, dipaddr;
00486     struct eth_addr netifaddr;
00487     netifaddr.addr[0] = netif->hwaddr[0];
00488     netifaddr.addr[1] = netif->hwaddr[1];
00489     netifaddr.addr[2] = netif->hwaddr[2];
00490     netifaddr.addr[3] = netif->hwaddr[3];
00491     netifaddr.addr[4] = netif->hwaddr[4];
00492     netifaddr.addr[5] = netif->hwaddr[5];
00493 
00494     /* Copy struct ip_addr2 to aligned ip_addr, to support compilers without
00495      * structure packing (not using structure copy which breaks strict-aliasing rules).
00496      */
00497     SMEMCPY(&sipaddr, &hdr->sipaddr, sizeof(sipaddr));
00498     SMEMCPY(&dipaddr, &hdr->dipaddr, sizeof(dipaddr));
00499       
00500     if ((netif->autoip->state == AUTOIP_STATE_PROBING) ||
00501         ((netif->autoip->state == AUTOIP_STATE_ANNOUNCING) &&
00502          (netif->autoip->sent_num == 0))) {
00503      /* RFC 3927 Section 2.2.1:
00504       * from beginning to after ANNOUNCE_WAIT
00505       * seconds we have a conflict if
00506       * ip.src == llipaddr OR
00507       * ip.dst == llipaddr && hw.src != own hwaddr
00508       */
00509       if ((ip_addr_cmp(&sipaddr, &netif->autoip->llipaddr)) ||
00510           (ip_addr_cmp(&dipaddr, &netif->autoip->llipaddr) &&
00511            !eth_addr_cmp(&netifaddr, &hdr->shwaddr))) {
00512         LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | LWIP_DBG_LEVEL_WARNING,
00513           ("autoip_arp_reply(): Probe Conflict detected\n"));
00514         autoip_start(netif);
00515       }
00516     } else {
00517      /* RFC 3927 Section 2.5:
00518       * in any state we have a conflict if
00519       * ip.src == llipaddr && hw.src != own hwaddr
00520       */
00521       if (ip_addr_cmp(&sipaddr, &netif->autoip->llipaddr) &&
00522           !eth_addr_cmp(&netifaddr, &hdr->shwaddr)) {
00523         LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | LWIP_DBG_LEVEL_WARNING,
00524           ("autoip_arp_reply(): Conflicting ARP-Packet detected\n"));
00525         autoip_handle_arp_conflict(netif);
00526       }
00527     }
00528   }
00529 }
00530 
00531 #endif /* LWIP_AUTOIP */