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1 /**
2  * @file
3  * AutoIP Automatic LinkLocal IP Configuration
4  *
5  * This is a AutoIP implementation for the lwIP TCP/IP stack. It aims to conform
6  * with RFC 3927.
7  *
8  * @defgroup autoip AUTOIP
9  * @ingroup ip4
10  * AUTOIP related functions
11  * USAGE:
12  *
13  * define @ref LWIP_AUTOIP 1 in your lwipopts.h
14  * Options:
15  * AUTOIP_TMR_INTERVAL msecs,
16  *   I recommend a value of 100. The value must divide 1000 with a remainder almost 0.
17  *   Possible values are 1000, 500, 333, 250, 200, 166, 142, 125, 111, 100 ....
18  *
19  * Without DHCP:
20  * - Call autoip_start() after netif_add().
21  *
22  * With DHCP:
23  * - define @ref LWIP_DHCP_AUTOIP_COOP 1 in your lwipopts.h.
24  * - Configure your DHCP Client.
25  *
26  * @see netifapi_autoip
27  */
28 
29 /*
30  *
31  * Copyright (c) 2007 Dominik Spies <kontakt@dspies.de>
32  * All rights reserved.
33  *
34  * Redistribution and use in source and binary forms, with or without modification,
35  * are permitted provided that the following conditions are met:
36  *
37  * 1. Redistributions of source code must retain the above copyright notice,
38  *    this list of conditions and the following disclaimer.
39  * 2. Redistributions in binary form must reproduce the above copyright notice,
40  *    this list of conditions and the following disclaimer in the documentation
41  *    and/or other materials provided with the distribution.
42  * 3. The name of the author may not be used to endorse or promote products
43  *    derived from this software without specific prior written permission.
44  *
45  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
46  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
47  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
48  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
49  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
50  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
51  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
52  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
53  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
54  * OF SUCH DAMAGE.
55  *
56  * Author: Dominik Spies <kontakt@dspies.de>
57  */
58 
59 #include "lwip/opt.h"
60 
61 #if LWIP_IPV4 && LWIP_AUTOIP /* don't build if not configured for use in lwipopts.h */
62 
63 #include "lwip/mem.h"
64 /* #include "lwip/udp.h" */
65 #include "lwip/ip_addr.h"
66 #include "lwip/netif.h"
67 #include "lwip/autoip.h"
68 #include "lwip/etharp.h"
69 #include "lwip/prot/autoip.h"
70 
71 #include <string.h>
72 
73 /** Pseudo random macro based on netif informations.
74  * You could use "rand()" from the C Library if you define LWIP_AUTOIP_RAND in lwipopts.h */
75 #ifndef LWIP_AUTOIP_RAND
76 #define LWIP_AUTOIP_RAND(netif) ( (((u32_t)((netif->hwaddr[5]) & 0xff) << 24) | \
77                                    ((u32_t)((netif->hwaddr[3]) & 0xff) << 16) | \
78                                    ((u32_t)((netif->hwaddr[2]) & 0xff) << 8) | \
79                                    ((u32_t)((netif->hwaddr[4]) & 0xff))) + \
80                                    (netif_autoip_data(netif)? netif_autoip_data(netif)->tried_llipaddr : 0))
81 #endif /* LWIP_AUTOIP_RAND */
82 
83 /**
84  * Macro that generates the initial IP address to be tried by AUTOIP.
85  * If you want to override this, define it to something else in lwipopts.h.
86  */
87 #ifndef LWIP_AUTOIP_CREATE_SEED_ADDR
88 #define LWIP_AUTOIP_CREATE_SEED_ADDR(netif) \
89   lwip_htonl(AUTOIP_RANGE_START + ((u32_t)(((u8_t)(netif->hwaddr[4])) | \
90                  ((u32_t)((u8_t)(netif->hwaddr[5]))) << 8)))
91 #endif /* LWIP_AUTOIP_CREATE_SEED_ADDR */
92 
93 /* static functions */
94 static err_t autoip_arp_announce(struct netif *netif);
95 static void autoip_start_probing(struct netif *netif);
96 
97 /**
98  * @ingroup autoip
99  * Set a statically allocated struct autoip to work with.
100  * Using this prevents autoip_start to allocate it using mem_malloc.
101  *
102  * @param netif the netif for which to set the struct autoip
103  * @param autoip (uninitialised) autoip struct allocated by the application
104  */
105 void
autoip_set_struct(struct netif * netif,struct autoip * autoip)106 autoip_set_struct(struct netif *netif, struct autoip *autoip)
107 {
108   LWIP_ASSERT_CORE_LOCKED();
109   LWIP_ASSERT("netif != NULL", netif != NULL);
110   LWIP_ASSERT("autoip != NULL", autoip != NULL);
111   LWIP_ASSERT("netif already has a struct autoip set",
112               netif_autoip_data(netif) == NULL);
113 
114   /* clear data structure */
115   memset(autoip, 0, sizeof(struct autoip));
116   /* autoip->state = AUTOIP_STATE_OFF; */
117   netif_set_client_data(netif, LWIP_NETIF_CLIENT_DATA_INDEX_AUTOIP, autoip);
118 }
119 
120 /** Restart AutoIP client and check the next address (conflict detected)
121  *
122  * @param netif The netif under AutoIP control
123  */
124 static void
autoip_restart(struct netif * netif)125 autoip_restart(struct netif *netif)
126 {
127   struct autoip *autoip = netif_autoip_data(netif);
128   autoip->tried_llipaddr++;
129   autoip_start(netif);
130 }
131 
132 /**
133  * Handle a IP address conflict after an ARP conflict detection
134  */
135 static void
autoip_handle_arp_conflict(struct netif * netif)136 autoip_handle_arp_conflict(struct netif *netif)
137 {
138   struct autoip *autoip = netif_autoip_data(netif);
139 
140   /* RFC3927, 2.5 "Conflict Detection and Defense" allows two options where
141      a) means retreat on the first conflict and
142      b) allows to keep an already configured address when having only one
143         conflict in 10 seconds
144      We use option b) since it helps to improve the chance that one of the two
145      conflicting hosts may be able to retain its address. */
146 
147   if (autoip->lastconflict > 0) {
148     /* retreat, there was a conflicting ARP in the last DEFEND_INTERVAL seconds */
149     LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
150                 ("autoip_handle_arp_conflict(): we are defending, but in DEFEND_INTERVAL, retreating\n"));
151 
152     /* Active TCP sessions are aborted when removing the ip addresss */
153     autoip_restart(netif);
154   } else {
155     LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
156                 ("autoip_handle_arp_conflict(): we are defend, send ARP Announce\n"));
157     autoip_arp_announce(netif);
158     autoip->lastconflict = DEFEND_INTERVAL * AUTOIP_TICKS_PER_SECOND;
159   }
160 }
161 
162 /**
163  * Create an IP-Address out of range 169.254.1.0 to 169.254.254.255
164  *
165  * @param netif network interface on which create the IP-Address
166  * @param ipaddr ip address to initialize
167  */
168 static void
autoip_create_addr(struct netif * netif,ip4_addr_t * ipaddr)169 autoip_create_addr(struct netif *netif, ip4_addr_t *ipaddr)
170 {
171   struct autoip *autoip = netif_autoip_data(netif);
172 
173   /* Here we create an IP-Address out of range 169.254.1.0 to 169.254.254.255
174    * compliant to RFC 3927 Section 2.1
175    * We have 254 * 256 possibilities */
176 
177   u32_t addr = lwip_ntohl(LWIP_AUTOIP_CREATE_SEED_ADDR(netif));
178   addr += autoip->tried_llipaddr;
179   addr = AUTOIP_NET | (addr & 0xffff);
180   /* Now, 169.254.0.0 <= addr <= 169.254.255.255 */
181 
182   if (addr < AUTOIP_RANGE_START) {
183     addr += AUTOIP_RANGE_END - AUTOIP_RANGE_START + 1;
184   }
185   if (addr > AUTOIP_RANGE_END) {
186     addr -= AUTOIP_RANGE_END - AUTOIP_RANGE_START + 1;
187   }
188   LWIP_ASSERT("AUTOIP address not in range", (addr >= AUTOIP_RANGE_START) &&
189               (addr <= AUTOIP_RANGE_END));
190   ip4_addr_set_u32(ipaddr, lwip_htonl(addr));
191 
192   LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
193               ("autoip_create_addr(): tried_llipaddr=%"U16_F", %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
194                (u16_t)(autoip->tried_llipaddr), ip4_addr1_16(ipaddr), ip4_addr2_16(ipaddr),
195                ip4_addr3_16(ipaddr), ip4_addr4_16(ipaddr)));
196 }
197 
198 /**
199  * Sends an ARP probe from a network interface
200  *
201  * @param netif network interface used to send the probe
202  */
203 static err_t
autoip_arp_probe(struct netif * netif)204 autoip_arp_probe(struct netif *netif)
205 {
206   struct autoip *autoip = netif_autoip_data(netif);
207   /* this works because netif->ip_addr is ANY */
208   return etharp_request(netif, &autoip->llipaddr);
209 }
210 
211 /**
212  * Sends an ARP announce from a network interface
213  *
214  * @param netif network interface used to send the announce
215  */
216 static err_t
autoip_arp_announce(struct netif * netif)217 autoip_arp_announce(struct netif *netif)
218 {
219   return etharp_gratuitous(netif);
220 }
221 
222 /**
223  * Configure interface for use with current LL IP-Address
224  *
225  * @param netif network interface to configure with current LL IP-Address
226  */
227 static err_t
autoip_bind(struct netif * netif)228 autoip_bind(struct netif *netif)
229 {
230   struct autoip *autoip = netif_autoip_data(netif);
231   ip4_addr_t sn_mask, gw_addr;
232 
233   LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
234               ("autoip_bind(netif=%p) %s%"U16_F" %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
235                (void *)netif, netif->name, (u16_t)netif->num,
236                ip4_addr1_16(&autoip->llipaddr), ip4_addr2_16(&autoip->llipaddr),
237                ip4_addr3_16(&autoip->llipaddr), ip4_addr4_16(&autoip->llipaddr)));
238 
239   IP4_ADDR(&sn_mask, 255, 255, 0, 0);
240   IP4_ADDR(&gw_addr, 0, 0, 0, 0);
241 
242   (void)netif_set_addr(netif, &autoip->llipaddr, &sn_mask, &gw_addr);
243   /* interface is used by routing now that an address is set */
244 
245   return ERR_OK;
246 }
247 
248 /**
249  * @ingroup autoip
250  * Start AutoIP client
251  *
252  * @param netif network interface on which start the AutoIP client
253  */
254 err_t
autoip_start(struct netif * netif)255 autoip_start(struct netif *netif)
256 {
257   struct autoip *autoip = NULL;
258   err_t result = ERR_OK;
259 
260   LWIP_ERROR("netif is NULL", (netif != NULL), return ERR_ARG);
261   LWIP_ERROR("netif is not up, old style port?", netif_is_up(netif), return ERR_ARG);
262 
263   autoip = netif_autoip_data(netif);
264 
265   /* Set IP-Address, Netmask and Gateway to 0 to make sure that
266    * ARP Packets are formed correctly
267    */
268   (void)netif_set_addr(netif, IP4_ADDR_ANY4, IP4_ADDR_ANY4, IP4_ADDR_ANY4);
269 
270   LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
271               ("autoip_start(netif=%p) %s%"U16_F"\n", (void *)netif, netif->name, (u16_t)netif->num));
272   if (autoip == NULL) {
273     /* no AutoIP client attached yet? */
274     LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
275                 ("autoip_start(): starting new AUTOIP client\n"));
276     autoip = (struct autoip *)mem_calloc(1, sizeof(struct autoip));
277     if (autoip == NULL) {
278       LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
279                   ("autoip_start(): could not allocate autoip\n"));
280       return ERR_MEM;
281     }
282     /* store this AutoIP client in the netif */
283     netif_set_client_data(netif, LWIP_NETIF_CLIENT_DATA_INDEX_AUTOIP, autoip);
284     LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, ("autoip_start(): allocated autoip"));
285   } else {
286     autoip->state = AUTOIP_STATE_OFF;
287     autoip->ttw = 0;
288     autoip->sent_num = 0;
289     ip4_addr_set_zero(&autoip->llipaddr);
290     autoip->lastconflict = 0;
291   }
292 
293   autoip_create_addr(netif, &(autoip->llipaddr));
294   autoip_start_probing(netif);
295 
296   return result;
297 }
298 
299 static void
autoip_start_probing(struct netif * netif)300 autoip_start_probing(struct netif *netif)
301 {
302   struct autoip *autoip = netif_autoip_data(netif);
303 
304   autoip->state = AUTOIP_STATE_PROBING;
305   autoip->sent_num = 0;
306   LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
307               ("autoip_start_probing(): changing state to PROBING: %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
308                ip4_addr1_16(&autoip->llipaddr), ip4_addr2_16(&autoip->llipaddr),
309                ip4_addr3_16(&autoip->llipaddr), ip4_addr4_16(&autoip->llipaddr)));
310 
311   /* time to wait to first probe, this is randomly
312    * chosen out of 0 to PROBE_WAIT seconds.
313    * compliant to RFC 3927 Section 2.2.1
314    */
315   autoip->ttw = (u16_t)(LWIP_AUTOIP_RAND(netif) % (PROBE_WAIT * AUTOIP_TICKS_PER_SECOND));
316 
317   /*
318    * if we tried more then MAX_CONFLICTS we must limit our rate for
319    * acquiring and probing address
320    * compliant to RFC 3927 Section 2.2.1
321    */
322   if (autoip->tried_llipaddr > MAX_CONFLICTS) {
323     autoip->ttw = RATE_LIMIT_INTERVAL * AUTOIP_TICKS_PER_SECOND;
324   }
325 }
326 
327 /**
328  * Handle a possible change in the network configuration.
329  *
330  * If there is an AutoIP address configured, take the interface down
331  * and begin probing with the same address.
332  */
333 void
autoip_network_changed(struct netif * netif)334 autoip_network_changed(struct netif *netif)
335 {
336   struct autoip *autoip = netif_autoip_data(netif);
337 
338   if (autoip && (autoip->state != AUTOIP_STATE_OFF)) {
339     autoip_start_probing(netif);
340   }
341 }
342 
343 /**
344  * @ingroup autoip
345  * Stop AutoIP client
346  *
347  * @param netif network interface on which stop the AutoIP client
348  */
349 err_t
autoip_stop(struct netif * netif)350 autoip_stop(struct netif *netif)
351 {
352   struct autoip *autoip = NULL;
353   LWIP_ERROR("netif is NULL", (netif != NULL), return ERR_ARG);
354 
355   autoip = netif_autoip_data(netif);
356   if (autoip != NULL) {
357     autoip->state = AUTOIP_STATE_OFF;
358     if (ip4_addr_islinklocal(netif_ip4_addr(netif))) {
359       (void)netif_set_addr(netif, IP4_ADDR_ANY4, IP4_ADDR_ANY4, IP4_ADDR_ANY4);
360     }
361   }
362   return ERR_OK;
363 }
364 
365 #if LWIP_LOWPOWER
366 #include "lwip/lowpower.h"
367 u32_t
autoip_tmr_tick(void)368 autoip_tmr_tick(void)
369 {
370   struct netif *netif = netif_list;
371   u32_t tick = 0;
372 
373   while (netif != NULL) {
374     struct autoip *autoip = netif_autoip_data(netif);
375     if ((autoip != NULL) && (autoip->ttw > 0)) {
376       if ((autoip->state == AUTOIP_STATE_PROBING) ||
377           (autoip->state == AUTOIP_STATE_ANNOUNCING)) {
378         SET_TMR_TICK(tick, autoip->ttw);
379       }
380     }
381     netif = netif->next;
382   }
383 
384   LOWPOWER_DEBUG(("%s tmr tick: %u\n", __func__, tick));
385   return tick;
386 }
387 
388 #endif
389 
390 /**
391  * Has to be called in loop every AUTOIP_TMR_INTERVAL milliseconds
392  */
393 void
autoip_tmr(void)394 autoip_tmr(void)
395 {
396   struct netif *netif;
397   /* loop through netif's */
398   NETIF_FOREACH(netif) {
399     struct autoip *autoip = netif_autoip_data(netif);
400     /* only act on AutoIP configured interfaces */
401     if (autoip != NULL) {
402       if (autoip->lastconflict > 0) {
403         autoip->lastconflict--;
404       }
405 
406       LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
407                   ("autoip_tmr() AutoIP-State: %"U16_F", ttw=%"U16_F"\n",
408                    (u16_t)(autoip->state), autoip->ttw));
409 
410       if (autoip->ttw > 0) {
411         autoip->ttw--;
412       }
413 
414       switch (autoip->state) {
415         case AUTOIP_STATE_PROBING:
416           if (autoip->ttw == 0) {
417             if (autoip->sent_num >= PROBE_NUM) {
418               /* Switch to ANNOUNCING: now we can bind to an IP address and use it */
419               autoip->state = AUTOIP_STATE_ANNOUNCING;
420               autoip_bind(netif);
421               /* autoip_bind() calls netif_set_addr(): this triggers a gratuitous ARP
422                  which counts as an announcement */
423               autoip->sent_num = 1;
424               autoip->ttw = ANNOUNCE_WAIT * AUTOIP_TICKS_PER_SECOND;
425               LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
426                           ("autoip_tmr(): changing state to ANNOUNCING: %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
427                            ip4_addr1_16(&autoip->llipaddr), ip4_addr2_16(&autoip->llipaddr),
428                            ip4_addr3_16(&autoip->llipaddr), ip4_addr4_16(&autoip->llipaddr)));
429             } else {
430               autoip_arp_probe(netif);
431               LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, ("autoip_tmr() PROBING Sent Probe\n"));
432               autoip->sent_num++;
433               if (autoip->sent_num == PROBE_NUM) {
434                 /* calculate time to wait to for announce */
435                 autoip->ttw = ANNOUNCE_WAIT * AUTOIP_TICKS_PER_SECOND;
436               } else {
437                 /* calculate time to wait to next probe */
438                 autoip->ttw = (u16_t)((LWIP_AUTOIP_RAND(netif) %
439                                        ((PROBE_MAX - PROBE_MIN) * AUTOIP_TICKS_PER_SECOND) ) +
440                                       PROBE_MIN * AUTOIP_TICKS_PER_SECOND);
441               }
442             }
443           }
444           break;
445 
446         case AUTOIP_STATE_ANNOUNCING:
447           if (autoip->ttw == 0) {
448             autoip_arp_announce(netif);
449             LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, ("autoip_tmr() ANNOUNCING Sent Announce\n"));
450             autoip->ttw = ANNOUNCE_INTERVAL * AUTOIP_TICKS_PER_SECOND;
451             autoip->sent_num++;
452 
453             if (autoip->sent_num >= ANNOUNCE_NUM) {
454               autoip->state = AUTOIP_STATE_BOUND;
455               autoip->sent_num = 0;
456               autoip->ttw = 0;
457               LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
458                           ("autoip_tmr(): changing state to BOUND: %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
459                            ip4_addr1_16(&autoip->llipaddr), ip4_addr2_16(&autoip->llipaddr),
460                            ip4_addr3_16(&autoip->llipaddr), ip4_addr4_16(&autoip->llipaddr)));
461             }
462           }
463           break;
464 
465         default:
466           /* nothing to do in other states */
467           break;
468       }
469     }
470   }
471 }
472 
473 /**
474  * Handles every incoming ARP Packet, called by etharp_input().
475  *
476  * @param netif network interface to use for autoip processing
477  * @param hdr Incoming ARP packet
478  */
479 void
autoip_arp_reply(struct netif * netif,struct etharp_hdr * hdr)480 autoip_arp_reply(struct netif *netif, struct etharp_hdr *hdr)
481 {
482   struct autoip *autoip = netif_autoip_data(netif);
483 
484   LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, ("autoip_arp_reply()\n"));
485   if ((autoip != NULL) && (autoip->state != AUTOIP_STATE_OFF)) {
486     /* when ip.src == llipaddr && hw.src != netif->hwaddr
487      *
488      * when probing  ip.dst == llipaddr && hw.src != netif->hwaddr
489      * we have a conflict and must solve it
490      */
491     ip4_addr_t sipaddr, dipaddr;
492     struct eth_addr netifaddr;
493     SMEMCPY(netifaddr.addr, netif->hwaddr, ETH_HWADDR_LEN);
494 
495     /* Copy struct ip4_addr_wordaligned to aligned ip4_addr, to support compilers without
496      * structure packing (not using structure copy which breaks strict-aliasing rules).
497      */
498     IPADDR_WORDALIGNED_COPY_TO_IP4_ADDR_T(&sipaddr, &hdr->sipaddr);
499     IPADDR_WORDALIGNED_COPY_TO_IP4_ADDR_T(&dipaddr, &hdr->dipaddr);
500 
501     if (autoip->state == AUTOIP_STATE_PROBING) {
502       /* RFC 3927 Section 2.2.1:
503        * from beginning to after ANNOUNCE_WAIT
504        * seconds we have a conflict if
505        * ip.src == llipaddr OR
506        * ip.dst == llipaddr && hw.src != own hwaddr
507        */
508       if ((ip4_addr_cmp(&sipaddr, &autoip->llipaddr)) ||
509           (ip4_addr_isany_val(sipaddr) &&
510            ip4_addr_cmp(&dipaddr, &autoip->llipaddr) &&
511            !eth_addr_cmp(&netifaddr, &hdr->shwaddr))) {
512         LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | LWIP_DBG_LEVEL_WARNING,
513                     ("autoip_arp_reply(): Probe Conflict detected\n"));
514         autoip_restart(netif);
515       }
516     } else {
517       /* RFC 3927 Section 2.5:
518        * in any state we have a conflict if
519        * ip.src == llipaddr && hw.src != own hwaddr
520        */
521       if (ip4_addr_cmp(&sipaddr, &autoip->llipaddr) &&
522           !eth_addr_cmp(&netifaddr, &hdr->shwaddr)) {
523         LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | LWIP_DBG_LEVEL_WARNING,
524                     ("autoip_arp_reply(): Conflicting ARP-Packet detected\n"));
525         autoip_handle_arp_conflict(netif);
526       }
527     }
528   }
529 }
530 
531 /** check if AutoIP supplied netif->ip_addr
532  *
533  * @param netif the netif to check
534  * @return 1 if AutoIP supplied netif->ip_addr (state BOUND or ANNOUNCING),
535  *         0 otherwise
536  */
537 u8_t
autoip_supplied_address(const struct netif * netif)538 autoip_supplied_address(const struct netif *netif)
539 {
540   if ((netif != NULL) && (netif_autoip_data(netif) != NULL)) {
541     struct autoip *autoip = netif_autoip_data(netif);
542     return (autoip->state == AUTOIP_STATE_BOUND) || (autoip->state == AUTOIP_STATE_ANNOUNCING);
543   }
544   return 0;
545 }
546 
547 u8_t
autoip_accept_packet(struct netif * netif,const ip4_addr_t * addr)548 autoip_accept_packet(struct netif *netif, const ip4_addr_t *addr)
549 {
550   struct autoip *autoip = netif_autoip_data(netif);
551   return (autoip != NULL) && ip4_addr_cmp(addr, &(autoip->llipaddr));
552 }
553 
554 #endif /* LWIP_IPV4 && LWIP_AUTOIP */
555