1 /**
2 * @file
3 * Address Resolution Protocol module for IP over Ethernet
4 *
5 * Functionally, ARP is divided into two parts. The first maps an IP address
6 * to a physical address when sending a packet, and the second part answers
7 * requests from other machines for our physical address.
8 *
9 * This implementation complies with RFC 826 (Ethernet ARP). It supports
10 * Gratuitious ARP from RFC3220 (IP Mobility Support for IPv4) section 4.6
11 * if an interface calls etharp_gratuitous(our_netif) upon address change.
12 */
13
14 /*
15 * Copyright (c) 2001-2003 Swedish Institute of Computer Science.
16 * Copyright (c) 2003-2004 Leon Woestenberg <leon.woestenberg@axon.tv>
17 * Copyright (c) 2003-2004 Axon Digital Design B.V., The Netherlands.
18 * All rights reserved.
19 *
20 * Redistribution and use in source and binary forms, with or without modification,
21 * are permitted provided that the following conditions are met:
22 *
23 * 1. Redistributions of source code must retain the above copyright notice,
24 * this list of conditions and the following disclaimer.
25 * 2. Redistributions in binary form must reproduce the above copyright notice,
26 * this list of conditions and the following disclaimer in the documentation
27 * and/or other materials provided with the distribution.
28 * 3. The name of the author may not be used to endorse or promote products
29 * derived from this software without specific prior written permission.
30 *
31 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
32 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
33 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
34 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
35 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
36 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
37 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
38 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
39 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
40 * OF SUCH DAMAGE.
41 *
42 * This file is part of the lwIP TCP/IP stack.
43 *
44 */
45
46 #include "lwip/opt.h"
47
48 #if LWIP_IPV4 && LWIP_ARP /* don't build if not configured for use in lwipopts.h */
49 #include "lwip/sys.h"
50 #include "lwip/etharp.h"
51 #include "lwip/stats.h"
52 #include "lwip/snmp.h"
53 #include "lwip/dhcp.h"
54 #include "lwip/autoip.h"
55 #include "lwip/prot/iana.h"
56 #include "netif/ethernet.h"
57
58 #include <string.h>
59
60 #if LWIP_NAT64
61 #include "lwip/nat64.h"
62 #endif
63
64 #ifdef LWIP_HOOK_FILENAME
65 #include LWIP_HOOK_FILENAME
66 #endif
67
68 /** Re-request a used ARP entry 1 minute before it would expire to prevent
69 * breaking a steadily used connection because the ARP entry timed out. */
70 #define ARP_AGE_REREQUEST_USED_UNICAST (ARP_MAXAGE - 30)
71 #define ARP_AGE_REREQUEST_USED_BROADCAST (ARP_MAXAGE - 15)
72
73 /** the time an ARP entry stays pending after first request,
74 * for ARP_TMR_INTERVAL = 1000, this is
75 * 10 seconds.
76 *
77 * @internal Keep this number at least 2, otherwise it might
78 * run out instantly if the timeout occurs directly after a request.
79 */
80 #define ARP_MAXPENDING 5
81
82 #if LWIP_ENABLE_IP_CONFLICT_SIGNAL
83 u32_t is_ip_conflict_signal = 0;
84 sys_sem_t ip_conflict_detect;
85 #endif
86 struct etharp_entry arp_table[ARP_TABLE_SIZE];
87
88 #if ETHARP_FAST_RTE
89 #define ARP_FAST_RTE_TIME 10
90 static ip4_addr_t g_last_unresolved_dest = { IPADDR_ANY };
91 static u16_t g_fast_rte_time;
92 #endif
93
94 #if !LWIP_NETIF_HWADDRHINT
95 static netif_addr_idx_t etharp_cached_entry;
96 #endif /* !LWIP_NETIF_HWADDRHINT */
97
98 #if LWIP_NETIF_HWADDRHINT
99 #define ETHARP_SET_ADDRHINT(netif, addrhint) do { if (((netif) != NULL) && ((netif)->hints != NULL)) { \
100 (netif)->hints->addr_hint = (addrhint); }} while(0)
101 #else /* LWIP_NETIF_HWADDRHINT */
102 #define ETHARP_SET_ADDRHINT(netif, addrhint) (etharp_cached_entry = (addrhint))
103 #endif /* LWIP_NETIF_HWADDRHINT */
104
105
106 /* Check for maximum ARP_TABLE_SIZE */
107 #if (ARP_TABLE_SIZE > NETIF_ADDR_IDX_MAX)
108 #error "ARP_TABLE_SIZE must fit in an s16_t, you have to reduce it in your lwipopts.h"
109 #endif
110
111
112 static err_t etharp_request_dst(struct netif *netif, const ip4_addr_t *ipaddr, const struct eth_addr *hw_dst_addr);
113 static err_t etharp_raw(struct netif *netif,
114 const struct eth_addr *ethsrc_addr, const struct eth_addr *ethdst_addr,
115 const struct eth_addr *hwsrc_addr, const ip4_addr_t *ipsrc_addr,
116 const struct eth_addr *hwdst_addr, const ip4_addr_t *ipdst_addr,
117 const u16_t opcode);
118
119 #if ARP_QUEUEING
120 /**
121 * Free a complete queue of etharp entries
122 *
123 * @param q a qeueue of etharp_q_entry's to free
124 */
125 static void
free_etharp_q(struct etharp_q_entry * q)126 free_etharp_q(struct etharp_q_entry *q)
127 {
128 struct etharp_q_entry *r;
129 LWIP_ASSERT("q != NULL", q != NULL);
130 while (q) {
131 r = q;
132 q = q->next;
133 LWIP_ASSERT("r->p != NULL", (r->p != NULL));
134 pbuf_free(r->p);
135 memp_free(MEMP_ARP_QUEUE, r);
136 }
137 }
138 #else /* ARP_QUEUEING */
139
140 /** Compatibility define: free the queued pbuf */
141 #define free_etharp_q(q) pbuf_free(q)
142
143 #endif /* ARP_QUEUEING */
144
145 /** Clean up ARP table entries */
146 static void
etharp_free_entry(s16_t i)147 etharp_free_entry(s16_t i)
148 {
149 /* remove from SNMP ARP index tree */
150 mib2_remove_arp_entry(arp_table[i].netif, &arp_table[i].ipaddr);
151 /* and empty packet queue */
152 if (arp_table[i].q != NULL) {
153 /* remove all queued packets */
154 LWIP_DEBUGF(ETHARP_DEBUG, ("etharp_free_entry: freeing entry %"U16_F", packet queue %p.\n", (u16_t)i, (void *)(arp_table[i].q)));
155 free_etharp_q(arp_table[i].q);
156 arp_table[i].q = NULL;
157 }
158 /* recycle entry for re-use */
159 arp_table[i].state = ETHARP_STATE_EMPTY;
160 #ifdef LWIP_DEBUG
161 /* for debugging, clean out the complete entry */
162 arp_table[i].ctime = 0;
163 arp_table[i].netif = NULL;
164 ip4_addr_set_zero(&arp_table[i].ipaddr);
165 arp_table[i].ethaddr = ethzero;
166 #endif /* LWIP_DEBUG */
167 }
168
169 #if LWIP_LOWPOWER
170 #include "lwip/lowpower.h"
171 u32_t
etharp_tmr_tick(void)172 etharp_tmr_tick(void)
173 {
174 s32_t i;
175 u32_t tick = 0;
176 u32_t time;
177
178 for (i = 0; i < ARP_TABLE_SIZE; i++) {
179 u8_t state = arp_table[i].state;
180 if ((state != ETHARP_STATE_EMPTY)
181 #if ETHARP_SUPPORT_STATIC_ENTRIES
182 && (state != ETHARP_STATE_STATIC)
183 #endif /* ETHARP_SUPPORT_STATIC_ENTRIES */
184 ) {
185 if (arp_table[i].state != ETHARP_STATE_STABLE) {
186 LOWPOWER_DEBUG(("%s tmr tick: 1\n", __func__));
187 return 1;
188 }
189 time = (u32_t)ARP_MAXAGE - arp_table[i].ctime;
190 SET_TMR_TICK(tick, time);
191 }
192 }
193 LOWPOWER_DEBUG(("%s tmr tick: %u\n", __func__, tick));
194 return tick;
195 }
196 #endif /* LWIP_LOWPOWER */
197
198 #if LWIP_ARP_GRATUITOUS_REXMIT
199 err_t
etharp_gratuitous_start(struct netif * netif)200 etharp_gratuitous_start(struct netif *netif)
201 {
202 if (netif == NULL) {
203 return ERR_ARG;
204 }
205 if ((netif->flags & NETIF_FLAG_ETHARP) == 0) {
206 return ERR_OPNOTSUPP;
207 }
208 (void)etharp_request(netif, netif_ip4_addr(netif));
209 netif->arp_gratuitous_doing = lwIP_TRUE;
210 netif->arp_gratuitous_cnt = 1;
211 return ERR_OK;
212 }
213
214 static void
etharp_gratuitous_retransmit(void)215 etharp_gratuitous_retransmit(void)
216 {
217 struct netif *netif;
218 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_gratuitous_retransmit()\n"));
219 /* iterate through all network interfaces */
220 NETIF_FOREACH(netif) {
221 if ((netif->flags & NETIF_FLAG_ETHARP) == 0) {
222 continue;
223 }
224 if (netif->arp_gratuitous_doing != lwIP_TRUE) {
225 continue;
226 }
227 if (netif->arp_gratuitous_cnt < ETHARP_GRATUITOUS_NUM) {
228 (void)etharp_request(netif, netif_ip4_addr(netif));
229 netif->arp_gratuitous_cnt++;
230 } else {
231 netif->arp_gratuitous_doing = lwIP_FALSE;
232 netif->arp_gratuitous_cnt = 0;
233 }
234 }
235 }
236 #endif /* LWIP_ARP_GRATUITOUS_REXMIT */
237
238 /**
239 * Clears expired entries in the ARP table.
240 *
241 * This function should be called every ARP_TMR_INTERVAL milliseconds (1 second),
242 * in order to expire entries in the ARP table.
243 */
244 void
etharp_tmr(void)245 etharp_tmr(void)
246 {
247 s16_t i;
248
249 LWIP_DEBUGF(ETHARP_DEBUG, ("etharp_timer\n"));
250
251 #if ETHARP_FAST_RTE
252 if (g_fast_rte_time > 0) {
253 --g_fast_rte_time;
254 if (g_fast_rte_time == 0) {
255 ip4_addr_set_any(&g_last_unresolved_dest);
256 }
257 }
258 #endif
259 /* remove expired entries from the ARP table */
260 for (i = 0; i < ARP_TABLE_SIZE; ++i) {
261 u8_t state = arp_table[i].state;
262 if (state != ETHARP_STATE_EMPTY
263 #if ETHARP_SUPPORT_STATIC_ENTRIES
264 && (state != ETHARP_STATE_STATIC)
265 #endif /* ETHARP_SUPPORT_STATIC_ENTRIES */
266 ) {
267 arp_table[i].ctime++;
268 if ((arp_table[i].ctime >= ARP_MAXAGE) ||
269 ((arp_table[i].state == ETHARP_STATE_PENDING) &&
270 (arp_table[i].ctime >= ARP_MAXPENDING))) {
271 /* pending or stable entry has become old! */
272 LWIP_DEBUGF(ETHARP_DEBUG, ("etharp_timer: expired %s entry %d.\n",
273 arp_table[i].state >= ETHARP_STATE_STABLE ? "stable" : "pending", i));
274 #if ETHARP_FAST_RTE
275 if (arp_table[i].state == ETHARP_STATE_PENDING) {
276 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE,
277 ("etharp_tmr: save the last unresolved ip %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
278 ip4_addr1_16_val(arp_table[i].ipaddr), ip4_addr2_16_val(arp_table[i].ipaddr),
279 ip4_addr3_16_val(arp_table[i].ipaddr), ip4_addr4_16_val(arp_table[i].ipaddr)));
280 ip4_addr_copy(g_last_unresolved_dest, arp_table[i].ipaddr);
281 g_fast_rte_time = ARP_FAST_RTE_TIME;
282 }
283 #endif
284 /* clean up entries that have just been expired */
285 etharp_free_entry(i);
286 } else if (arp_table[i].state == ETHARP_STATE_STABLE_REREQUESTING_1) {
287 /* Don't send more than one request every 2 seconds. */
288 arp_table[i].state = ETHARP_STATE_STABLE_REREQUESTING_2;
289 } else if (arp_table[i].state == ETHARP_STATE_STABLE_REREQUESTING_2) {
290 /* Reset state to stable, so that the next transmitted packet will
291 re-send an ARP request. */
292 arp_table[i].state = ETHARP_STATE_STABLE;
293 } else if (arp_table[i].state == ETHARP_STATE_PENDING) {
294 /* still pending, resend an ARP query */
295 etharp_request(arp_table[i].netif, &arp_table[i].ipaddr);
296 }
297 }
298 }
299 #if LWIP_ARP_GRATUITOUS_REXMIT
300 etharp_gratuitous_retransmit();
301 #endif
302 }
303
304 /**
305 * Search the ARP table for a matching or new entry.
306 *
307 * If an IP address is given, return a pending or stable ARP entry that matches
308 * the address. If no match is found, create a new entry with this address set,
309 * but in state ETHARP_EMPTY. The caller must check and possibly change the
310 * state of the returned entry.
311 *
312 * If ipaddr is NULL, return a initialized new entry in state ETHARP_EMPTY.
313 *
314 * In all cases, attempt to create new entries from an empty entry. If no
315 * empty entries are available and ETHARP_FLAG_TRY_HARD flag is set, recycle
316 * old entries. Heuristic choose the least important entry for recycling.
317 *
318 * @param ipaddr IP address to find in ARP cache, or to add if not found.
319 * @param flags See @ref etharp_state
320 * @param netif netif related to this address (used for NETIF_HWADDRHINT)
321 *
322 * @return The ARP entry index that matched or is created, ERR_MEM if no
323 * entry is found or could be recycled.
324 */
325 static s16_t
etharp_find_entry(const ip4_addr_t * ipaddr,u8_t flags,struct netif * netif)326 etharp_find_entry(const ip4_addr_t *ipaddr, u8_t flags, struct netif *netif)
327 {
328 s16_t old_pending = ARP_TABLE_SIZE, old_stable = ARP_TABLE_SIZE;
329 s16_t empty = ARP_TABLE_SIZE;
330 s16_t i = 0;
331 /* oldest entry with packets on queue */
332 s16_t old_queue = ARP_TABLE_SIZE;
333 /* its age */
334 u16_t age_queue = 0, age_pending = 0, age_stable = 0;
335
336 LWIP_UNUSED_ARG(netif);
337
338 /**
339 * a) do a search through the cache, remember candidates
340 * b) select candidate entry
341 * c) create new entry
342 */
343
344 /* a) in a single search sweep, do all of this
345 * 1) remember the first empty entry (if any)
346 * 2) remember the oldest stable entry (if any)
347 * 3) remember the oldest pending entry without queued packets (if any)
348 * 4) remember the oldest pending entry with queued packets (if any)
349 * 5) search for a matching IP entry, either pending or stable
350 * until 5 matches, or all entries are searched for.
351 */
352
353 for (i = 0; i < ARP_TABLE_SIZE; ++i) {
354 u8_t state = arp_table[i].state;
355 /* no empty entry found yet and now we do find one? */
356 if ((empty == ARP_TABLE_SIZE) && (state == ETHARP_STATE_EMPTY)) {
357 LWIP_DEBUGF(ETHARP_DEBUG, ("etharp_find_entry: found empty entry %d\n", (int)i));
358 /* remember first empty entry */
359 empty = i;
360 } else if (state != ETHARP_STATE_EMPTY) {
361 LWIP_ASSERT("state == ETHARP_STATE_PENDING || state >= ETHARP_STATE_STABLE",
362 state == ETHARP_STATE_PENDING || state >= ETHARP_STATE_STABLE);
363 /* if given, does IP address match IP address in ARP entry? */
364 if (ipaddr && ip4_addr_cmp(ipaddr, &arp_table[i].ipaddr)
365 #if ETHARP_TABLE_MATCH_NETIF
366 && ((netif == NULL) || (netif == arp_table[i].netif))
367 #endif /* ETHARP_TABLE_MATCH_NETIF */
368 ) {
369 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_find_entry: found matching entry %d\n", (int)i));
370 /* found exact IP address match, simply bail out */
371 return i;
372 }
373 /* pending entry? */
374 if (state == ETHARP_STATE_PENDING) {
375 /* pending with queued packets? */
376 if (arp_table[i].q != NULL) {
377 if (arp_table[i].ctime >= age_queue) {
378 old_queue = i;
379 age_queue = arp_table[i].ctime;
380 }
381 } else
382 /* pending without queued packets? */
383 {
384 if (arp_table[i].ctime >= age_pending) {
385 old_pending = i;
386 age_pending = arp_table[i].ctime;
387 }
388 }
389 /* stable entry? */
390 } else if (state >= ETHARP_STATE_STABLE) {
391 #if ETHARP_SUPPORT_STATIC_ENTRIES
392 /* don't record old_stable for static entries since they never expire */
393 if (state < ETHARP_STATE_STATIC)
394 #endif /* ETHARP_SUPPORT_STATIC_ENTRIES */
395 {
396 /* remember entry with oldest stable entry in oldest, its age in maxtime */
397 if (arp_table[i].ctime >= age_stable) {
398 old_stable = i;
399 age_stable = arp_table[i].ctime;
400 }
401 }
402 }
403 }
404 }
405 /* { we have no match } => try to create a new entry */
406
407 /* don't create new entry, only search? */
408 if (((flags & ETHARP_FLAG_FIND_ONLY) != 0) ||
409 /* or no empty entry found and not allowed to recycle? */
410 ((empty == ARP_TABLE_SIZE) && ((flags & ETHARP_FLAG_TRY_HARD) == 0))) {
411 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_find_entry: no empty entry found and not allowed to recycle\n"));
412 return (s16_t)ERR_MEM;
413 }
414
415 /* b) choose the least destructive entry to recycle:
416 * 1) empty entry
417 * 2) oldest stable entry
418 * 3) oldest pending entry without queued packets
419 * 4) oldest pending entry with queued packets
420 *
421 * { ETHARP_FLAG_TRY_HARD is set at this point }
422 */
423
424 /* 1) empty entry available? */
425 if (empty < ARP_TABLE_SIZE) {
426 i = empty;
427 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_find_entry: selecting empty entry %d\n", (int)i));
428 } else {
429 /* 2) found recyclable stable entry? */
430 if (old_stable < ARP_TABLE_SIZE) {
431 /* recycle oldest stable*/
432 i = old_stable;
433 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_find_entry: selecting oldest stable entry %d\n", (int)i));
434 /* no queued packets should exist on stable entries */
435 LWIP_ASSERT("arp_table[i].q == NULL", arp_table[i].q == NULL);
436 /* 3) found recyclable pending entry without queued packets? */
437 } else if (old_pending < ARP_TABLE_SIZE) {
438 /* recycle oldest pending */
439 i = old_pending;
440 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_find_entry: selecting oldest pending entry %d (without queue)\n", (int)i));
441 /* 4) found recyclable pending entry with queued packets? */
442 } else if (old_queue < ARP_TABLE_SIZE) {
443 /* recycle oldest pending (queued packets are free in etharp_free_entry) */
444 i = old_queue;
445 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_find_entry: selecting oldest pending entry %d, freeing packet queue %p\n", (int)i, (void *)(arp_table[i].q)));
446 /* no empty or recyclable entries found */
447 } else {
448 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_find_entry: no empty or recyclable entries found\n"));
449 return (s16_t)ERR_MEM;
450 }
451
452 /* { empty or recyclable entry found } */
453 LWIP_ASSERT("i < ARP_TABLE_SIZE", i < ARP_TABLE_SIZE);
454 etharp_free_entry(i);
455 }
456
457 LWIP_ASSERT("i < ARP_TABLE_SIZE", i < ARP_TABLE_SIZE);
458 LWIP_ASSERT("arp_table[i].state == ETHARP_STATE_EMPTY",
459 arp_table[i].state == ETHARP_STATE_EMPTY);
460
461 /* IP address given? */
462 if (ipaddr != NULL) {
463 /* set IP address */
464 ip4_addr_copy(arp_table[i].ipaddr, *ipaddr);
465 }
466 arp_table[i].ctime = 0;
467 #if ETHARP_TABLE_MATCH_NETIF
468 arp_table[i].netif = netif;
469 #endif /* ETHARP_TABLE_MATCH_NETIF */
470 return (s16_t)i;
471 }
472
473 /**
474 * Update (or insert) a IP/MAC address pair in the ARP cache.
475 *
476 * If a pending entry is resolved, any queued packets will be sent
477 * at this point.
478 *
479 * @param netif netif related to this entry (used for NETIF_ADDRHINT)
480 * @param ipaddr IP address of the inserted ARP entry.
481 * @param ethaddr Ethernet address of the inserted ARP entry.
482 * @param flags See @ref etharp_state
483 *
484 * @return
485 * - ERR_OK Successfully updated ARP cache.
486 * - ERR_MEM If we could not add a new ARP entry when ETHARP_FLAG_TRY_HARD was set.
487 * - ERR_ARG Non-unicast address given, those will not appear in ARP cache.
488 *
489 * @see pbuf_free()
490 */
491 err_t
etharp_update_arp_entry(struct netif * netif,const ip4_addr_t * ipaddr,struct eth_addr * ethaddr,u8_t flags)492 etharp_update_arp_entry(struct netif *netif, const ip4_addr_t *ipaddr, struct eth_addr *ethaddr, u8_t flags)
493 {
494 s16_t i;
495 LWIP_ASSERT("netif->hwaddr_len == ETH_HWADDR_LEN", netif->hwaddr_len == ETH_HWADDR_LEN);
496 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_update_arp_entry: %"U16_F".%"U16_F".%"U16_F".%"U16_F" - %02"X16_F":%02"X16_F":%02"X16_F":%02"X16_F":%02"X16_F":%02"X16_F"\n",
497 ip4_addr1_16(ipaddr), ip4_addr2_16(ipaddr), ip4_addr3_16(ipaddr), ip4_addr4_16(ipaddr),
498 (u16_t)ethaddr->addr[0], (u16_t)ethaddr->addr[1], (u16_t)ethaddr->addr[2],
499 (u16_t)ethaddr->addr[3], (u16_t)ethaddr->addr[4], (u16_t)ethaddr->addr[5]));
500 /* non-unicast address? */
501 if (ip4_addr_isany(ipaddr) ||
502 ip4_addr_isbroadcast(ipaddr, netif) ||
503 ip4_addr_ismulticast(ipaddr)) {
504 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_update_arp_entry: will not add non-unicast IP address to ARP cache\n"));
505 return ERR_ARG;
506 }
507 /* find or create ARP entry */
508 i = etharp_find_entry(ipaddr, flags, netif);
509 /* bail out if no entry could be found */
510 if (i < 0) {
511 return (err_t)i;
512 }
513
514 #if ETHARP_SUPPORT_STATIC_ENTRIES
515 if (flags & ETHARP_FLAG_STATIC_ENTRY) {
516 /* record static type */
517 arp_table[i].state = ETHARP_STATE_STATIC;
518 } else if (arp_table[i].state == ETHARP_STATE_STATIC) {
519 /* found entry is a static type, don't overwrite it */
520 return ERR_VAL;
521 } else
522 #endif /* ETHARP_SUPPORT_STATIC_ENTRIES */
523 {
524 /* mark it stable */
525 arp_table[i].state = ETHARP_STATE_STABLE;
526 }
527
528 #if ETHARP_FAST_RTE
529 if (ip4_addr_cmp(ipaddr, &g_last_unresolved_dest)) {
530 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE,
531 ("etharp_update_arp_entry: ip %"U16_F".%"U16_F".%"U16_F".%"U16_F" is resolved now\n",
532 ip4_addr1_16(ipaddr), ip4_addr2_16(ipaddr), ip4_addr3_16(ipaddr), ip4_addr4_16(ipaddr)));
533 g_fast_rte_time = 0;
534 ip4_addr_set_any(&g_last_unresolved_dest);
535 }
536 #endif
537
538 /* record network interface */
539 arp_table[i].netif = netif;
540 /* insert in SNMP ARP index tree */
541 mib2_add_arp_entry(netif, &arp_table[i].ipaddr);
542
543 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_update_arp_entry: updating stable entry %"S16_F"\n", i));
544 /* update address */
545 SMEMCPY(&arp_table[i].ethaddr, ethaddr, ETH_HWADDR_LEN);
546 /* reset time stamp */
547 arp_table[i].ctime = 0;
548 /* this is where we will send out queued packets! */
549 #if ARP_QUEUEING
550 while (arp_table[i].q != NULL) {
551 struct pbuf *p;
552 /* remember remainder of queue */
553 struct etharp_q_entry *q = arp_table[i].q;
554 /* pop first item off the queue */
555 arp_table[i].q = q->next;
556 /* get the packet pointer */
557 p = q->p;
558 /* now queue entry can be freed */
559 memp_free(MEMP_ARP_QUEUE, q);
560 #else /* ARP_QUEUEING */
561 if (arp_table[i].q != NULL) {
562 struct pbuf *p = arp_table[i].q;
563 arp_table[i].q = NULL;
564 #endif /* ARP_QUEUEING */
565 /* send the queued IP packet */
566 ethernet_output(netif, p, (struct eth_addr *)(netif->hwaddr), ethaddr, ETHTYPE_IP);
567 /* free the queued IP packet */
568 pbuf_free(p);
569 }
570
571 return ERR_OK;
572 }
573
574 /*
575 * delete a IP/MAC_address pair in the ARP cache.
576 *
577 * @param netif netif related to this entry (used for NETIF_ADDRHINT)
578 * @param ipaddr IP_add of the inserted ARP entry.
579 *
580 * @return
581 * - ERR_OK Succesfully updated ARP cache..
582 * - ERR_ARG Non-unicast address given, or the entry is not found, or the entry
583 * state is not ETHARP_STATE_STABLE.
584 */
585 err_t
586 etharp_delete_arp_entry(struct netif *netif, const ip4_addr_t *ipaddr)
587 {
588 s16_t i;
589 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE,
590 ("etharp_delete_arp_entry: %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
591 ip4_addr1_16(ipaddr), ip4_addr2_16(ipaddr), ip4_addr3_16(ipaddr), ip4_addr4_16(ipaddr)));
592 /* non-unicast address? */
593 if (ip4_addr_isany(ipaddr) ||
594 ip4_addr_isbroadcast(ipaddr, netif) ||
595 ip4_addr_ismulticast(ipaddr)) {
596 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE,
597 ("etharp_update_arp_entry: will not add non-unicast IP_addr to ARP cache\n"));
598 return ERR_ARG;
599 }
600 /* find or create ARP entry */
601 i = etharp_find_entry(ipaddr, ETHARP_FLAG_FIND_ONLY, netif);
602 /* bail out if no entry could be found */
603 if (i < 0) {
604 return ERR_ARG;
605 }
606
607 /* entry found, free it */
608 etharp_free_entry(i);
609 return ERR_OK;
610 }
611
612 #if ETHARP_SUPPORT_STATIC_ENTRIES
613 /** Add a new static entry to the ARP table. If an entry exists for the
614 * specified IP address, this entry is overwritten.
615 * If packets are queued for the specified IP address, they are sent out.
616 *
617 * @param ipaddr IP address for the new static entry
618 * @param ethaddr ethernet address for the new static entry
619 * @return See return values of etharp_add_static_entry
620 */
621 err_t
622 etharp_add_static_entry(const ip4_addr_t *ipaddr, struct eth_addr *ethaddr)
623 {
624 struct netif *netif;
625 LWIP_ASSERT_CORE_LOCKED();
626 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_add_static_entry: %"U16_F".%"U16_F".%"U16_F".%"U16_F" - %02"X16_F":%02"X16_F":%02"X16_F":%02"X16_F":%02"X16_F":%02"X16_F"\n",
627 ip4_addr1_16(ipaddr), ip4_addr2_16(ipaddr), ip4_addr3_16(ipaddr), ip4_addr4_16(ipaddr),
628 (u16_t)ethaddr->addr[0], (u16_t)ethaddr->addr[1], (u16_t)ethaddr->addr[2],
629 (u16_t)ethaddr->addr[3], (u16_t)ethaddr->addr[4], (u16_t)ethaddr->addr[5]));
630
631 netif = ip4_route(ipaddr);
632 if (netif == NULL) {
633 return ERR_RTE;
634 }
635
636 return etharp_update_arp_entry(netif, ipaddr, ethaddr, ETHARP_FLAG_TRY_HARD | ETHARP_FLAG_STATIC_ENTRY);
637 }
638
639 /** Remove a static entry from the ARP table previously added with a call to
640 * etharp_add_static_entry.
641 *
642 * @param ipaddr IP address of the static entry to remove
643 * @return ERR_OK: entry removed
644 * ERR_MEM: entry wasn't found
645 * ERR_ARG: entry wasn't a static entry but a dynamic one
646 */
647 err_t
648 etharp_remove_static_entry(const ip4_addr_t *ipaddr)
649 {
650 s16_t i;
651 LWIP_ASSERT_CORE_LOCKED();
652 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_remove_static_entry: %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
653 ip4_addr1_16(ipaddr), ip4_addr2_16(ipaddr), ip4_addr3_16(ipaddr), ip4_addr4_16(ipaddr)));
654
655 /* find or create ARP entry */
656 i = etharp_find_entry(ipaddr, ETHARP_FLAG_FIND_ONLY, NULL);
657 /* bail out if no entry could be found */
658 if (i < 0) {
659 return (err_t)i;
660 }
661
662 if (arp_table[i].state != ETHARP_STATE_STATIC) {
663 /* entry wasn't a static entry, cannot remove it */
664 return ERR_ARG;
665 }
666 /* entry found, free it */
667 etharp_free_entry(i);
668 return ERR_OK;
669 }
670 #endif /* ETHARP_SUPPORT_STATIC_ENTRIES */
671
672 /**
673 * Remove all ARP table entries of the specified netif.
674 *
675 * @param netif points to a network interface
676 */
677 void
678 etharp_cleanup_netif(struct netif *netif)
679 {
680 s16_t i;
681
682 for (i = 0; i < ARP_TABLE_SIZE; ++i) {
683 u8_t state = arp_table[i].state;
684 if ((state != ETHARP_STATE_EMPTY) && (arp_table[i].netif == netif)) {
685 etharp_free_entry(i);
686 }
687 }
688 }
689
690 /**
691 * Finds (stable) ethernet/IP address pair from ARP table
692 * using interface and IP address index.
693 * @note the addresses in the ARP table are in network order!
694 *
695 * @param netif points to interface index
696 * @param ipaddr points to the (network order) IP address index
697 * @param eth_ret points to return pointer
698 * @param ip_ret points to return pointer
699 * @return table index if found, -1 otherwise
700 */
701 ssize_t
702 etharp_find_addr(struct netif *netif, const ip4_addr_t *ipaddr,
703 struct eth_addr **eth_ret, const ip4_addr_t **ip_ret)
704 {
705 s16_t i;
706
707 LWIP_ASSERT("eth_ret != NULL && ip_ret != NULL",
708 eth_ret != NULL && ip_ret != NULL);
709
710 LWIP_UNUSED_ARG(netif);
711
712 i = etharp_find_entry(ipaddr, ETHARP_FLAG_FIND_ONLY, netif);
713 if ((i >= 0) && (arp_table[i].state >= ETHARP_STATE_STABLE)) {
714 *eth_ret = &arp_table[i].ethaddr;
715 *ip_ret = &arp_table[i].ipaddr;
716 return i;
717 }
718 return -1;
719 }
720
721 err_t
722 etharp_ip_to_mac(const ip4_addr_t *ipaddr, u8_t *mac, u8_t *maclen)
723 {
724 const ip4_addr_t *ip_add = NULL;
725 struct eth_addr *tdst_mac = NULL;
726 s8_t ret;
727
728 if (*maclen < ETH_HWADDR_LEN) {
729 return ERR_VAL;
730 }
731
732 ret = etharp_find_addr(NULL, ipaddr, &tdst_mac, &ip_add);
733 if (ret == -1) {
734 return ERR_NOADDR;
735 }
736
737 if (memcpy_s(mac, *maclen, tdst_mac->addr, ETH_HWADDR_LEN) != EOK) {
738 return ERR_MEM;
739 }
740 *maclen = ETH_HWADDR_LEN;
741
742 return ERR_OK;
743 }
744
745 /**
746 * Possibility to iterate over stable ARP table entries
747 *
748 * @param i entry number, 0 to ARP_TABLE_SIZE
749 * @param ipaddr return value: IP address
750 * @param netif return value: points to interface
751 * @param eth_ret return value: ETH address
752 * @return 1 on valid index, 0 otherwise
753 */
754 int
755 etharp_get_entry(size_t i, ip4_addr_t **ipaddr, struct netif **netif, struct eth_addr **eth_ret)
756 {
757 LWIP_ASSERT("ipaddr != NULL", ipaddr != NULL);
758 LWIP_ASSERT("netif != NULL", netif != NULL);
759 LWIP_ASSERT("eth_ret != NULL", eth_ret != NULL);
760
761 if ((i < ARP_TABLE_SIZE) && (arp_table[i].state >= ETHARP_STATE_STABLE)) {
762 *ipaddr = &arp_table[i].ipaddr;
763 *netif = arp_table[i].netif;
764 *eth_ret = &arp_table[i].ethaddr;
765 return 1;
766 } else {
767 return 0;
768 }
769 }
770
771 #if ETHARP_TRUST_IP_MAC
772 /**
773 * Updates the ARP table using the given IP packet.
774 *
775 * Uses the incoming IP packet's source address to update the
776 * ARP cache for the local network. The function does not alter
777 * or free the packet. This function must be called before the
778 * packet p is passed to the IP layer.
779 *
780 * @param netif The lwIP network interface on which the IP packet pbuf arrived.
781 * @param p The IP packet that arrived on netif.
782 *
783 * @return NULL
784 *
785 * @see pbuf_free()
786 */
787 void
788 etharp_ip_input(struct netif *netif, struct pbuf *p)
789 {
790 struct eth_hdr *ethhdr = NULL;
791 struct ip_hdr *iphdr = NULL;
792 ip4_addr_t iphdr_src;
793 struct netif *loc_netif = NULL;
794 err_t err;
795
796 LWIP_ERROR("netif != NULL", (netif != NULL), return);
797
798 /* Only insert an entry if the source IP_add of the
799 incoming IP packet comes from a host on the local network. */
800 ethhdr = (struct eth_hdr *)p->payload;
801
802 #if ETHARP_SUPPORT_VLAN
803 if (ethhdr->type == PP_HTONS(ETHTYPE_VLAN)) {
804 /* drop the packet as IP header size is small */
805 if (p->len < SIZEOF_ETH_HDR + SIZEOF_VLAN_HDR + IP_HLEN) {
806 return;
807 }
808
809 iphdr = (struct ip_hdr *)((u8_t*)ethhdr + SIZEOF_ETH_HDR + SIZEOF_VLAN_HDR);
810 } else
811 #endif /* ETHARP_SUPPORT_VLAN */
812 {
813 /* drop the packet as IP header size is small */
814 if (p->len < SIZEOF_ETH_HDR + IP_HLEN) {
815 return;
816 }
817
818 iphdr = (struct ip_hdr *)((u8_t*)ethhdr + SIZEOF_ETH_HDR);
819 }
820
821 ip4_addr_copy(iphdr_src, iphdr->src);
822
823 /* source is not on the local network? */
824 if (!ip4_addr_netcmp(&iphdr_src, ip_2_ip4(&(netif->ip_addr)), ip_2_ip4(&(netif->netmask)))) {
825 loc_netif = netif_list;
826 while (loc_netif != NULL) {
827 if (loc_netif == netif) {
828 loc_netif = loc_netif->next;
829 continue;
830 }
831
832 if ((!strncmp(loc_netif->name, netif->name, NETIF_NAMESIZE)) && (loc_netif->num == netif->num)) {
833 netif = loc_netif;
834 break;
835 }
836 loc_netif = loc_netif->next;
837 }
838 if (loc_netif == NULL) {
839 /* do nothing */
840 return;
841 }
842 }
843
844 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_ip_input: updating ETHARP table.\n"));
845 /* update the source IP_add in the cache, if present */
846 /* @Note We could use ETHARP_FLAG_TRY_HARD if we think we are going to talk
847 * back soon (for example, if the destination IP_add is ours. */
848 err = etharp_update_arp_entry(netif, &iphdr_src, &(ethhdr->src), ETHARP_FLAG_FIND_ONLY);
849 if (err != ERR_OK) {
850 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_ip_input: updating ETHARP table return ERROR.\n"));
851 }
852 return;
853 }
854 #endif /* ETHARP_TRUST_IP_MAC */
855
856 /**
857 * Responds to ARP requests to us. Upon ARP replies to us, add entry to cache
858 * send out queued IP packets. Updates cache with snooped address pairs.
859 *
860 * Should be called for incoming ARP packets. The pbuf in the argument
861 * is freed by this function.
862 *
863 * @param p The ARP packet that arrived on netif. Is freed by this function.
864 * @param netif The lwIP network interface on which the ARP packet pbuf arrived.
865 *
866 * @see pbuf_free()
867 */
868 void
869 etharp_input(struct pbuf *p, struct netif *netif)
870 {
871 struct etharp_hdr *hdr;
872 const ip4_addr_t *targetip = NULL;
873 /* these are aligned properly, whereas the ARP header fields might not be */
874 ip4_addr_t sipaddr, dipaddr;
875 u8_t for_us;
876
877 LWIP_ASSERT_CORE_LOCKED();
878
879 LWIP_ERROR("netif != NULL", (netif != NULL), return;);
880
881 hdr = (struct etharp_hdr *)p->payload;
882
883 /* drop short ARP packets: we have to check for p->len instead of p->tot_len here
884 since a struct etharp_hdr is pointed to p->payload, so it musn't be chained! */
885 if (p->len < SIZEOF_ETHARP_HDR) {
886 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING,
887 ("etharp_input: packet dropped, wrong hw type, hwlen, proto, protolen or ethernet type ( \
888 %"U16_F"/%"U16_F"/%"U16_F"/%"U16_F")\n",
889 hdr->hwtype, (u16_t)hdr->hwlen, hdr->proto, (u16_t)hdr->protolen));
890 ETHARP_STATS_INC(etharp.proterr);
891 ETHARP_STATS_INC(etharp.drop);
892 (void)pbuf_free(p);
893 return;
894 }
895
896 /* RFC 826 "Packet Reception": */
897 if ((hdr->hwtype != PP_HTONS(LWIP_IANA_HWTYPE_ETHERNET)) ||
898 (hdr->hwlen != ETH_HWADDR_LEN) ||
899 (hdr->protolen != sizeof(ip4_addr_t)) ||
900 (hdr->proto != PP_HTONS(ETHTYPE_IP))) {
901 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING,
902 ("etharp_input: packet dropped, wrong hw type, hwlen, proto, protolen or ethernet type (%"U16_F"/%"U16_F"/%"U16_F"/%"U16_F")\n",
903 hdr->hwtype, (u16_t)hdr->hwlen, hdr->proto, (u16_t)hdr->protolen));
904 ETHARP_STATS_INC(etharp.proterr);
905 ETHARP_STATS_INC(etharp.drop);
906 pbuf_free(p);
907 return;
908 }
909 ETHARP_STATS_INC(etharp.recv);
910
911 #if LWIP_AUTOIP
912 /* We have to check if a host already has configured our random
913 * created link local address and continuously check if there is
914 * a host with this IP-address so we can detect collisions */
915 autoip_arp_reply(netif, hdr);
916 #endif /* LWIP_AUTOIP */
917
918 /* Copy struct ip4_addr_wordaligned to aligned ip4_addr, to support compilers without
919 * structure packing (not using structure copy which breaks strict-aliasing rules). */
920 IPADDR_WORDALIGNED_COPY_TO_IP4_ADDR_T(&sipaddr, &hdr->sipaddr);
921 IPADDR_WORDALIGNED_COPY_TO_IP4_ADDR_T(&dipaddr, &hdr->dipaddr);
922
923 targetip = netif_ip4_addr(netif);
924 /* this interface is not configured? */
925 if (ip4_addr_isany_val(*targetip)) {
926 for_us = 0;
927 } else {
928 /* ARP packet directed to us? */
929 for_us = (u8_t)ip4_addr_cmp(&dipaddr, netif_ip4_addr(netif));
930 #if LWIP_NAT64
931 if ((for_us == 0) && (nat64_arp_ip4_is_proxy(sipaddr, dipaddr) == lwIP_TRUE)) {
932 targetip = &dipaddr;
933 for_us = 1;
934 }
935 #endif
936 }
937
938 /* ARP message directed to us?
939 -> add IP address in ARP cache; assume requester wants to talk to us,
940 can result in directly sending the queued packets for this host.
941 ARP message not directed to us?
942 -> update the source IP address in the cache, if present */
943 etharp_update_arp_entry(netif, &sipaddr, &(hdr->shwaddr),
944 for_us ? ETHARP_FLAG_TRY_HARD : ETHARP_FLAG_FIND_ONLY);
945
946 /* now act on the message itself */
947 switch (hdr->opcode) {
948 /* ARP request? */
949 case PP_HTONS(ARP_REQUEST):
950 /* ARP request. If it asked for our address, we send out a
951 * reply. In any case, we time-stamp any existing ARP entry,
952 * and possibly send out an IP packet that was queued on it. */
953
954 LWIP_DEBUGF (ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_input: incoming ARP request\n"));
955 /* ARP request for our address? */
956 if (for_us) {
957 /* send ARP response */
958 etharp_raw(netif,
959 (struct eth_addr *)netif->hwaddr, &hdr->shwaddr,
960 (struct eth_addr *)netif->hwaddr, targetip,
961 &hdr->shwaddr, &sipaddr,
962 ARP_REPLY);
963 /* we are not configured? */
964 } else if (ip4_addr_isany_val(*netif_ip4_addr(netif))) {
965 /* { for_us == 0 and netif->ip_addr.addr == 0 } */
966 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_input: we are unconfigured, ARP request ignored.\n"));
967 /* request was not directed to us */
968 } else {
969 /* { for_us == 0 and netif->ip_addr.addr != 0 } */
970 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_input: ARP request was not for us.\n"));
971 }
972 break;
973 case PP_HTONS(ARP_REPLY):
974 /* ARP reply. We already updated the ARP cache earlier. */
975 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_input: incoming ARP reply\n"));
976
977 #if LWIP_ENABLE_IP_CONFLICT_SIGNAL
978 if (ip4_addr_cmp(&sipaddr, netif_ip4_addr(netif))) {
979 /* Receive an arp reply. It means there is already a device use the same ip in the network. */
980 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_arp_input: Ip conflict.\n"));
981 if (is_ip_conflict_signal) {
982 #if LWIP_ARP_GRATUITOUS_REXMIT
983 netif->arp_gratuitous_doing = lwIP_FALSE;
984 netif->arp_gratuitous_cnt = 0;
985 #endif
986 sys_sem_signal(&ip_conflict_detect);
987 }
988 }
989 #endif
990
991 #if (LWIP_DHCP && DHCP_DOES_ARP_CHECK)
992 /* DHCP wants to know about ARP replies from any host with an
993 * IP address also offered to us by the DHCP server. We do not
994 * want to take a duplicate IP address on a single network.
995 * @todo How should we handle redundant (fail-over) interfaces? */
996 dhcp_arp_reply(netif, &sipaddr);
997 #endif /* (LWIP_DHCP && DHCP_DOES_ARP_CHECK) */
998 break;
999 default:
1000 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_input: ARP unknown opcode type %"S16_F"\n", lwip_htons(hdr->opcode)));
1001 ETHARP_STATS_INC(etharp.err);
1002 break;
1003 }
1004 /* free ARP packet */
1005 (void)pbuf_free(p);
1006 }
1007
1008 /** Just a small helper function that sends a pbuf to an ethernet address
1009 * in the arp_table specified by the index 'arp_idx'.
1010 */
1011 static err_t
1012 etharp_output_to_arp_index(struct netif *netif, struct pbuf *q, netif_addr_idx_t arp_idx)
1013 {
1014 LWIP_ASSERT("arp_table[arp_idx].state >= ETHARP_STATE_STABLE",
1015 arp_table[arp_idx].state >= ETHARP_STATE_STABLE);
1016 /* if arp table entry is about to expire: re-request it,
1017 but only if its state is ETHARP_STATE_STABLE to prevent flooding the
1018 network with ARP requests if this address is used frequently. */
1019 if (arp_table[arp_idx].state == ETHARP_STATE_STABLE) {
1020 if (arp_table[arp_idx].ctime >= ARP_AGE_REREQUEST_USED_BROADCAST) {
1021 /* issue a standard request using broadcast */
1022 if (etharp_request(netif, &arp_table[arp_idx].ipaddr) == ERR_OK) {
1023 arp_table[arp_idx].state = ETHARP_STATE_STABLE_REREQUESTING_1;
1024 }
1025 } else if (arp_table[arp_idx].ctime >= ARP_AGE_REREQUEST_USED_UNICAST) {
1026 /* issue a unicast request (for 15 seconds) to prevent unnecessary broadcast */
1027 if (etharp_request_dst(netif, &arp_table[arp_idx].ipaddr, &arp_table[arp_idx].ethaddr) == ERR_OK) {
1028 arp_table[arp_idx].state = ETHARP_STATE_STABLE_REREQUESTING_1;
1029 }
1030 }
1031 }
1032
1033 return ethernet_output(netif, q, (struct eth_addr *)(netif->hwaddr), &arp_table[arp_idx].ethaddr, ETHTYPE_IP);
1034 }
1035
1036 #if ETHARP_TABLE_MATCH_NETIF
1037 #define LWIP_ETHARP_MATCH_NETIF(_etharp_cached_entry, _netif) \
1038 (arp_table[(_etharp_cached_entry)].netif == (_netif)) &&
1039 #else
1040 #define LWIP_ETHARP_MATCH_NETIF(_etharp_cached_entry, _netif)
1041 #endif
1042 /**
1043 * Resolve and fill-in Ethernet address header for outgoing IP packet.
1044 *
1045 * For IP multicast and broadcast, corresponding Ethernet addresses
1046 * are selected and the packet is transmitted on the link.
1047 *
1048 * For unicast addresses, the packet is submitted to etharp_query(). In
1049 * case the IP address is outside the local network, the IP address of
1050 * the gateway is used.
1051 *
1052 * @param netif The lwIP network interface which the IP packet will be sent on.
1053 * @param q The pbuf(s) containing the IP packet to be sent.
1054 * @param ipaddr The IP address of the packet destination.
1055 *
1056 * @return
1057 * - ERR_RTE No route to destination (no gateway to external networks),
1058 * or the return type of either etharp_query() or ethernet_output().
1059 */
1060 err_t
1061 etharp_output(struct netif *netif, struct pbuf *q, const ip4_addr_t *ipaddr)
1062 {
1063 const struct eth_addr *dest;
1064 struct eth_addr mcastaddr;
1065 const ip4_addr_t *dst_addr = ipaddr;
1066
1067 LWIP_ASSERT_CORE_LOCKED();
1068 LWIP_ASSERT("netif != NULL", netif != NULL);
1069 LWIP_ASSERT("q != NULL", q != NULL);
1070 LWIP_ASSERT("ipaddr != NULL", ipaddr != NULL);
1071
1072 #if DRIVER_STATUS_CHECK
1073 if (netif_is_ready(netif) == 0) {
1074 LWIP_DEBUGF(ETHARP_DEBUG, ("etharp_output: netif driver not ready\n"));
1075 /* Do not drop if it is a DHCP buffer */
1076 if (!(q->flags & PBUF_FLAG_DHCP_BUF)) {
1077 /* Drop the packet here and return success */
1078 return ERR_OK;
1079 }
1080 }
1081 #endif
1082
1083 #if LWIP_DROP_PKT_WHEN_NETIF_DOWN
1084 if (!netif_is_up(netif) ||
1085 !netif_is_link_up(netif)) {
1086 LWIP_DEBUGF(ETHARP_DEBUG, ("etharp_output: Only send packet when both driver and lwip states are up\n"));
1087 (void)pbuf_free(q);
1088 return ERR_OK;
1089 }
1090 #endif
1091
1092 /* Determine on destination hardware address. Broadcasts and multicasts
1093 * are special, other IP addresses are looked up in the ARP table. */
1094
1095 /* broadcast destination IP address? */
1096 if (ip4_addr_isbroadcast(ipaddr, netif)) {
1097 /* broadcast on Ethernet also */
1098 dest = (const struct eth_addr *)ðbroadcast;
1099 /* multicast destination IP address? */
1100 } else if (ip4_addr_ismulticast(ipaddr)) {
1101 /* Hash IP multicast address to MAC address.*/
1102 mcastaddr.addr[0] = LL_IP4_MULTICAST_ADDR_0;
1103 mcastaddr.addr[1] = LL_IP4_MULTICAST_ADDR_1;
1104 mcastaddr.addr[2] = LL_IP4_MULTICAST_ADDR_2;
1105 mcastaddr.addr[3] = ip4_addr2(ipaddr) & 0x7f;
1106 mcastaddr.addr[4] = ip4_addr3(ipaddr);
1107 mcastaddr.addr[5] = ip4_addr4(ipaddr);
1108 /* destination Ethernet address is multicast */
1109 dest = &mcastaddr;
1110 /* unicast destination IP address? */
1111 } else {
1112 netif_addr_idx_t i;
1113 /* outside local network? if so, this can neither be a global broadcast nor
1114 a subnet broadcast. */
1115 /* the "PBUF_FLAG_IS_LINK_ONLY" flag means that the destination is also the nexthop,
1116 use the destination to do ARP resolution, don't use the gateway as the nexthop. */
1117 if (!ip4_addr_netcmp(ipaddr, netif_ip4_addr(netif), netif_ip4_netmask(netif)) &&
1118 !ip4_addr_islinklocal(ipaddr)
1119 #if LWIP_SO_DONTROUTE
1120 && !(q->flags & PBUF_FLAG_IS_LINK_ONLY)
1121 #endif /* LWIP_SO_DONTROUTE */
1122 ) {
1123 #if LWIP_AUTOIP
1124 struct ip_hdr *iphdr = LWIP_ALIGNMENT_CAST(struct ip_hdr *, q->payload);
1125 /* According to RFC 3297, chapter 2.6.2 (Forwarding Rules), a packet with
1126 a link-local source address must always be "directly to its destination
1127 on the same physical link. The host MUST NOT send the packet to any
1128 router for forwarding". */
1129 if (!ip4_addr_islinklocal(&iphdr->src))
1130 #endif /* LWIP_AUTOIP */
1131 {
1132 #ifdef LWIP_HOOK_ETHARP_GET_GW
1133 /* For advanced routing, a single default gateway might not be enough, so get
1134 the IP address of the gateway to handle the current destination address. */
1135 dst_addr = LWIP_HOOK_ETHARP_GET_GW(netif, ipaddr);
1136 if (dst_addr == NULL)
1137 #endif /* LWIP_HOOK_ETHARP_GET_GW */
1138 {
1139 /* interface has default gateway? */
1140 if (!ip4_addr_isany_val(*netif_ip4_gw(netif))) {
1141 /* send to hardware address of default gateway IP address */
1142 dst_addr = netif_ip4_gw(netif);
1143 /* no default gateway available */
1144 } else {
1145 /* no route to destination error (default gateway missing) */
1146 return ERR_RTE;
1147 }
1148 }
1149 }
1150 }
1151 #if LWIP_NETIF_HWADDRHINT
1152 if (netif->hints != NULL) {
1153 /* per-pcb cached entry was given */
1154 netif_addr_idx_t etharp_cached_entry = netif->hints->addr_hint;
1155 if (etharp_cached_entry < ARP_TABLE_SIZE) {
1156 #endif /* LWIP_NETIF_HWADDRHINT */
1157 if ((arp_table[etharp_cached_entry].state >= ETHARP_STATE_STABLE) &&
1158 (arp_table[etharp_cached_entry].netif == netif) &&
1159 LWIP_ETHARP_MATCH_NETIF(etharp_cached_entry, netif)
1160 (ip4_addr_cmp(dst_addr, &arp_table[etharp_cached_entry].ipaddr))) {
1161 /* the per-pcb-cached entry is stable and the right one! */
1162 ETHARP_STATS_INC(etharp.cachehit);
1163 return etharp_output_to_arp_index(netif, q, etharp_cached_entry);
1164 }
1165 #if LWIP_NETIF_HWADDRHINT
1166 }
1167 }
1168 #endif /* LWIP_NETIF_HWADDRHINT */
1169
1170 /* find stable entry: do this here since this is a critical path for
1171 throughput and etharp_find_entry() is kind of slow */
1172 for (i = 0; i < ARP_TABLE_SIZE; i++) {
1173 if ((arp_table[i].state >= ETHARP_STATE_STABLE) &&
1174 #if ETHARP_TABLE_MATCH_NETIF
1175 (arp_table[i].netif == netif) &&
1176 #endif
1177 (ip4_addr_cmp(dst_addr, &arp_table[i].ipaddr))) {
1178 /* found an existing, stable entry */
1179 ETHARP_SET_ADDRHINT(netif, i);
1180 return etharp_output_to_arp_index(netif, q, i);
1181 }
1182 }
1183 /* no stable entry found, use the (slower) query function:
1184 queue on destination Ethernet address belonging to ipaddr */
1185 return etharp_query(netif, dst_addr, q);
1186 }
1187
1188 /* continuation for multicast/broadcast destinations */
1189 /* obtain source Ethernet address of the given interface */
1190 /* send packet directly on the link */
1191 return ethernet_output(netif, q, (struct eth_addr *)(netif->hwaddr), dest, ETHTYPE_IP);
1192 }
1193
1194 /**
1195 * Send an ARP request for the given IP address and/or queue a packet.
1196 *
1197 * If the IP address was not yet in the cache, a pending ARP cache entry
1198 * is added and an ARP request is sent for the given address. The packet
1199 * is queued on this entry.
1200 *
1201 * If the IP address was already pending in the cache, a new ARP request
1202 * is sent for the given address. The packet is queued on this entry.
1203 *
1204 * If the IP address was already stable in the cache, and a packet is
1205 * given, it is directly sent and no ARP request is sent out.
1206 *
1207 * If the IP address was already stable in the cache, and no packet is
1208 * given, an ARP request is sent out.
1209 *
1210 * @param netif The lwIP network interface on which ipaddr
1211 * must be queried for.
1212 * @param ipaddr The IP address to be resolved.
1213 * @param q If non-NULL, a pbuf that must be delivered to the IP address.
1214 * q is not freed by this function.
1215 *
1216 * @note q must only be ONE packet, not a packet queue!
1217 *
1218 * @return
1219 * - ERR_BUF Could not make room for Ethernet header.
1220 * - ERR_MEM Hardware address unknown, and no more ARP entries available
1221 * to query for address or queue the packet.
1222 * - ERR_MEM Could not queue packet due to memory shortage.
1223 * - ERR_RTE No route to destination (no gateway to external networks).
1224 * - ERR_ARG Non-unicast address given, those will not appear in ARP cache.
1225 *
1226 */
1227 err_t
1228 etharp_query(struct netif *netif, const ip4_addr_t *ipaddr, struct pbuf *q)
1229 {
1230 struct eth_addr *srcaddr = (struct eth_addr *)netif->hwaddr;
1231 err_t result = ERR_MEM;
1232 int is_new_entry = 0;
1233 s16_t i_err;
1234 netif_addr_idx_t i;
1235
1236 /* non-unicast address? */
1237 if (ip4_addr_isbroadcast(ipaddr, netif) ||
1238 ip4_addr_ismulticast(ipaddr) ||
1239 ip4_addr_isany(ipaddr)) {
1240 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: will not add non-unicast IP address to ARP cache\n"));
1241 return ERR_ARG;
1242 }
1243
1244 /* find entry in ARP cache, ask to create entry if queueing packet */
1245 i_err = etharp_find_entry(ipaddr, ETHARP_FLAG_TRY_HARD, netif);
1246
1247 /* could not find or create entry? */
1248 if (i_err < 0) {
1249 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: could not create ARP entry\n"));
1250 if (q) {
1251 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: packet dropped\n"));
1252 ETHARP_STATS_INC(etharp.memerr);
1253 }
1254 return (err_t)i_err;
1255 }
1256 LWIP_ASSERT("type overflow", (size_t)i_err < NETIF_ADDR_IDX_MAX);
1257 i = (netif_addr_idx_t)i_err;
1258
1259 /* mark a fresh entry as pending (we just sent a request) */
1260 if (arp_table[i].state == ETHARP_STATE_EMPTY) {
1261 is_new_entry = 1;
1262 arp_table[i].state = ETHARP_STATE_PENDING;
1263 /* record network interface for re-sending arp request in etharp_tmr */
1264 arp_table[i].netif = netif;
1265 }
1266
1267 /* { i is either a STABLE or (new or existing) PENDING entry } */
1268 LWIP_ASSERT("arp_table[i].state == PENDING or STABLE",
1269 ((arp_table[i].state == ETHARP_STATE_PENDING) ||
1270 (arp_table[i].state >= ETHARP_STATE_STABLE)));
1271
1272 /* do we have a new entry? or an implicit query request? */
1273 if (is_new_entry || (q == NULL)) {
1274 /* try to resolve it; send out ARP request */
1275 result = etharp_request(netif, ipaddr);
1276 if (result != ERR_OK) {
1277 /* ARP request couldn't be sent */
1278 /* We don't re-send arp request in etharp_tmr, but we still queue packets,
1279 since this failure could be temporary, and the next packet calling
1280 etharp_query again could lead to sending the queued packets. */
1281 } else {
1282 /* ARP request successfully sent */
1283 if ((arp_table[i].state == ETHARP_STATE_PENDING) && !is_new_entry) {
1284 /* A new ARP request has been sent for a pending entry. Reset the ctime to
1285 not let it expire too fast. */
1286 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: reset ctime for entry %"S16_F"\n", (s16_t)i));
1287 arp_table[i].ctime = 0;
1288 }
1289 }
1290 if (q == NULL) {
1291 return result;
1292 }
1293 }
1294
1295 /* packet given? */
1296 LWIP_ASSERT("q != NULL", q != NULL);
1297 /* stable entry? */
1298 if (arp_table[i].state >= ETHARP_STATE_STABLE) {
1299 /* we have a valid IP->Ethernet address mapping */
1300 ETHARP_SET_ADDRHINT(netif, i);
1301 /* send the packet */
1302 result = ethernet_output(netif, q, srcaddr, &(arp_table[i].ethaddr), ETHTYPE_IP);
1303 /* pending entry? (either just created or already pending */
1304 } else if (arp_table[i].state == ETHARP_STATE_PENDING) {
1305 #if ETHARP_FAST_RTE
1306 if (ip4_addr_cmp(ipaddr, &g_last_unresolved_dest)) {
1307 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE,
1308 ("etharp_query: try sending to the last unresolved ip %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
1309 ip4_addr1_16(ipaddr), ip4_addr2_16(ipaddr), ip4_addr3_16(ipaddr), ip4_addr4_16(ipaddr)));
1310 result = ERR_RTE;
1311 return result;
1312 }
1313 #endif
1314 /* entry is still pending, queue the given packet 'q' */
1315 struct pbuf *p;
1316 int copy_needed = 0;
1317 /* IF q includes a pbuf that must be copied, copy the whole chain into a
1318 * new PBUF_RAM. See the definition of PBUF_NEEDS_COPY for details. */
1319 p = q;
1320 while (p) {
1321 LWIP_ASSERT("no packet queues allowed!", (p->len != p->tot_len) || (p->next == 0));
1322 if (PBUF_NEEDS_COPY(p)) {
1323 copy_needed = 1;
1324 break;
1325 }
1326 p = p->next;
1327 }
1328 if (copy_needed) {
1329 /* copy the whole packet into new pbufs */
1330 p = pbuf_clone(PBUF_LINK, PBUF_RAM, q);
1331 } else {
1332 /* referencing the old pbuf is enough */
1333 p = q;
1334 pbuf_ref(p);
1335 }
1336 /* packet could be taken over? */
1337 if (p != NULL) {
1338 /* queue packet ... */
1339 #if ARP_QUEUEING
1340 struct etharp_q_entry *new_entry;
1341 /* allocate a new arp queue entry */
1342 new_entry = (struct etharp_q_entry *)memp_malloc(MEMP_ARP_QUEUE);
1343 if (new_entry != NULL) {
1344 unsigned int qlen = 0;
1345 new_entry->next = 0;
1346 new_entry->p = p;
1347 if (arp_table[i].q != NULL) {
1348 /* queue was already existent, append the new entry to the end */
1349 struct etharp_q_entry *r;
1350 r = arp_table[i].q;
1351 qlen++;
1352 while (r->next != NULL) {
1353 r = r->next;
1354 qlen++;
1355 }
1356 r->next = new_entry;
1357 } else {
1358 /* queue did not exist, first item in queue */
1359 arp_table[i].q = new_entry;
1360 }
1361 #if ARP_QUEUE_LEN
1362 if (qlen >= ARP_QUEUE_LEN) {
1363 struct etharp_q_entry *old;
1364 old = arp_table[i].q;
1365 arp_table[i].q = arp_table[i].q->next;
1366 pbuf_free(old->p);
1367 memp_free(MEMP_ARP_QUEUE, old);
1368 }
1369 #endif
1370 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: queued packet %p on ARP entry %"U16_F"\n", (void *)q, i));
1371 result = ERR_OK;
1372 } else {
1373 /* the pool MEMP_ARP_QUEUE is empty */
1374 pbuf_free(p);
1375 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: could not queue a copy of PBUF_REF packet %p (out of memory)\n", (void *)q));
1376 result = ERR_MEM;
1377 }
1378 #else /* ARP_QUEUEING */
1379 /* always queue one packet per ARP request only, freeing a previously queued packet */
1380 if (arp_table[i].q != NULL) {
1381 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: dropped previously queued packet %p for ARP entry %"U16_F"\n", (void *)q, (u16_t)i));
1382 pbuf_free(arp_table[i].q);
1383 }
1384 arp_table[i].q = p;
1385 result = ERR_OK;
1386 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: queued packet %p on ARP entry %"U16_F"\n", (void *)q, (u16_t)i));
1387 #endif /* ARP_QUEUEING */
1388 } else {
1389 ETHARP_STATS_INC(etharp.memerr);
1390 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: could not queue a copy of PBUF_REF packet %p (out of memory)\n", (void *)q));
1391 result = ERR_MEM;
1392 }
1393 }
1394 return result;
1395 }
1396
1397 /**
1398 * Send a raw ARP packet (opcode and all addresses can be modified)
1399 *
1400 * @param netif the lwip network interface on which to send the ARP packet
1401 * @param ethsrc_addr the source MAC address for the ethernet header
1402 * @param ethdst_addr the destination MAC address for the ethernet header
1403 * @param hwsrc_addr the source MAC address for the ARP protocol header
1404 * @param ipsrc_addr the source IP address for the ARP protocol header
1405 * @param hwdst_addr the destination MAC address for the ARP protocol header
1406 * @param ipdst_addr the destination IP address for the ARP protocol header
1407 * @param opcode the type of the ARP packet
1408 * @return ERR_OK if the ARP packet has been sent
1409 * ERR_MEM if the ARP packet couldn't be allocated
1410 * any other err_t on failure
1411 */
1412 static err_t
1413 etharp_raw(struct netif *netif, const struct eth_addr *ethsrc_addr,
1414 const struct eth_addr *ethdst_addr,
1415 const struct eth_addr *hwsrc_addr, const ip4_addr_t *ipsrc_addr,
1416 const struct eth_addr *hwdst_addr, const ip4_addr_t *ipdst_addr,
1417 const u16_t opcode)
1418 {
1419 struct pbuf *p;
1420 err_t result = ERR_OK;
1421 struct etharp_hdr *hdr;
1422 struct netif *tmp_netif = NULL;
1423 LWIP_ASSERT("netif != NULL", netif != NULL);
1424 for (tmp_netif = netif_list; tmp_netif != NULL; tmp_netif = tmp_netif->next) {
1425 if (tmp_netif == netif) {
1426 break;
1427 }
1428 }
1429 if (tmp_netif != netif) {
1430 return ERR_OK; /* netif is not on the list */
1431 }
1432 /* allocate a pbuf for the outgoing ARP request packet */
1433 p = pbuf_alloc(PBUF_LINK, SIZEOF_ETHARP_HDR, PBUF_RAM);
1434 /* could allocate a pbuf for an ARP request? */
1435 if (p == NULL) {
1436 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS,
1437 ("etharp_raw: could not allocate pbuf for ARP request.\n"));
1438 ETHARP_STATS_INC(etharp.memerr);
1439 return ERR_MEM;
1440 }
1441 LWIP_ASSERT("check that first pbuf can hold struct etharp_hdr",
1442 (p->len >= SIZEOF_ETHARP_HDR));
1443
1444 hdr = (struct etharp_hdr *)p->payload;
1445 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_raw: sending raw ARP packet.\n"));
1446 hdr->opcode = lwip_htons(opcode);
1447
1448 LWIP_ASSERT("netif->hwaddr_len must be the same as ETH_HWADDR_LEN for etharp!",
1449 (netif->hwaddr_len == ETH_HWADDR_LEN));
1450
1451 /* Write the ARP MAC-Addresses */
1452 SMEMCPY(&hdr->shwaddr, hwsrc_addr, ETH_HWADDR_LEN);
1453 SMEMCPY(&hdr->dhwaddr, hwdst_addr, ETH_HWADDR_LEN);
1454 /* Copy struct ip4_addr_wordaligned to aligned ip4_addr, to support compilers without
1455 * structure packing. */
1456 IPADDR_WORDALIGNED_COPY_FROM_IP4_ADDR_T(&hdr->sipaddr, ipsrc_addr);
1457 IPADDR_WORDALIGNED_COPY_FROM_IP4_ADDR_T(&hdr->dipaddr, ipdst_addr);
1458
1459 hdr->hwtype = PP_HTONS(LWIP_IANA_HWTYPE_ETHERNET);
1460 hdr->proto = PP_HTONS(ETHTYPE_IP);
1461 /* set hwlen and protolen */
1462 hdr->hwlen = ETH_HWADDR_LEN;
1463 hdr->protolen = sizeof(ip4_addr_t);
1464
1465 /* send ARP query */
1466 #if LWIP_AUTOIP
1467 /* If we are using Link-Local, all ARP packets that contain a Link-Local
1468 * 'sender IP address' MUST be sent using link-layer broadcast instead of
1469 * link-layer unicast. (See RFC3927 Section 2.5, last paragraph) */
1470 if (ip4_addr_islinklocal(ipsrc_addr)) {
1471 ethernet_output(netif, p, ethsrc_addr, ðbroadcast, ETHTYPE_ARP);
1472 } else
1473 #endif /* LWIP_AUTOIP */
1474 {
1475 ethernet_output(netif, p, ethsrc_addr, ethdst_addr, ETHTYPE_ARP);
1476 }
1477
1478 ETHARP_STATS_INC(etharp.xmit);
1479 /* free ARP query packet */
1480 pbuf_free(p);
1481 p = NULL;
1482 /* could not allocate pbuf for ARP request */
1483
1484 return result;
1485 }
1486
1487 /**
1488 * Send an ARP request packet asking for ipaddr to a specific eth address.
1489 * Used to send unicast request to refresh the ARP table just before an entry
1490 * times out
1491 *
1492 * @param netif the lwip network interface on which to send the request
1493 * @param ipaddr the IP address for which to ask
1494 * @param hw_dst_addr the ethernet address to send this packet to
1495 * @return ERR_OK if the request has been sent
1496 * ERR_MEM if the ARP packet couldn't be allocated
1497 * any other err_t on failure
1498 */
1499 static err_t
1500 etharp_request_dst(struct netif *netif, const ip4_addr_t *ipaddr, const struct eth_addr *hw_dst_addr)
1501 {
1502 return etharp_raw(netif, (struct eth_addr *)netif->hwaddr, hw_dst_addr,
1503 (struct eth_addr *)netif->hwaddr, netif_ip4_addr(netif), ðzero,
1504 ipaddr, ARP_REQUEST);
1505 }
1506
1507 /**
1508 * Send an ARP request packet asking for ipaddr.
1509 *
1510 * @param netif the lwip network interface on which to send the request
1511 * @param ipaddr the IP address for which to ask
1512 * @return ERR_OK if the request has been sent
1513 * ERR_MEM if the ARP packet couldn't be allocated
1514 * any other err_t on failure
1515 */
1516 err_t
1517 etharp_request(struct netif *netif, const ip4_addr_t *ipaddr)
1518 {
1519 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_request: sending ARP request.\n"));
1520 return etharp_request_dst(netif, ipaddr, ðbroadcast);
1521 }
1522
1523 /**
1524 * Send an ARP request packet announcing an ipaddr.
1525 *
1526 * @param netif the lwip network interface on which to send the request
1527 * @param ipaddr the IP address to announce
1528 * @return ERR_OK if the request has been sent
1529 * ERR_MEM if the ARP packet couldn't be allocated
1530 * any other err_t on failure
1531 */
1532 err_t
1533 etharp_announce(struct netif *netif, const ip4_addr_t *ipaddr)
1534 {
1535 return etharp_raw(netif, (struct eth_addr *)netif->hwaddr, ðbroadcast,
1536 (struct eth_addr *)netif->hwaddr, ipaddr, ðzero,
1537 ipaddr, ARP_REQUEST);
1538 }
1539 #endif /* LWIP_IPV4 && LWIP_ARP */
1540