3 * Address Resolution Protocol module for IP over Ethernet
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.
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.
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.
20 * Redistribution and use in source and binary forms, with or without modification,
21 * are permitted provided that the following conditions are met:
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.
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
42 * This file is part of the lwIP TCP/IP stack.
48 #if LWIP_ARP || LWIP_ETHERNET
50 #include "lwip/ip_addr.h"
53 #include "lwip/stats.h"
54 #include "lwip/snmp.h"
55 #include "lwip/dhcp.h"
56 #include "lwip/autoip.h"
57 #include "netif/etharp.h"
60 #include "netif/ppp_oe.h"
61 #endif /* PPPOE_SUPPORT */
65 const struct eth_addr ethbroadcast = {{0xff,0xff,0xff,0xff,0xff,0xff}};
66 const struct eth_addr ethzero = {{0,0,0,0,0,0}};
68 #if LWIP_ARP /* don't build if not configured for use in lwipopts.h */
70 /** the time an ARP entry stays valid after its last update,
71 * for ARP_TMR_INTERVAL = 5000, this is
72 * (240 * 5) seconds = 20 minutes.
74 #define ARP_MAXAGE 240
75 /** the time an ARP entry stays pending after first request,
76 * for ARP_TMR_INTERVAL = 5000, this is
77 * (2 * 5) seconds = 10 seconds.
79 * @internal Keep this number at least 2, otherwise it might
80 * run out instantly if the timeout occurs directly after a request.
82 #define ARP_MAXPENDING 2
84 #define HWTYPE_ETHERNET 1
87 ETHARP_STATE_EMPTY = 0,
94 /** Pointer to queue of pending outgoing packets on this ARP entry. */
95 struct etharp_q_entry *q;
96 #endif /* ARP_QUEUEING */
98 struct eth_addr ethaddr;
101 #endif /* LWIP_SNMP */
104 #if ETHARP_SUPPORT_STATIC_ENTRIES
106 #endif /* ETHARP_SUPPORT_STATIC_ENTRIES */
109 static struct etharp_entry arp_table[ARP_TABLE_SIZE];
111 #if !LWIP_NETIF_HWADDRHINT
112 static u8_t etharp_cached_entry;
113 #endif /* !LWIP_NETIF_HWADDRHINT */
115 /** Try hard to create a new entry - we want the IP address to appear in
116 the cache (even if this means removing an active entry or so). */
117 #define ETHARP_FLAG_TRY_HARD 1
118 #define ETHARP_FLAG_FIND_ONLY 2
119 #define ETHARP_FLAG_STATIC_ENTRY 4
121 #if LWIP_NETIF_HWADDRHINT
122 #define ETHARP_SET_HINT(netif, hint) if (((netif) != NULL) && ((netif)->addr_hint != NULL)) \
123 *((netif)->addr_hint) = (hint);
124 #else /* LWIP_NETIF_HWADDRHINT */
125 #define ETHARP_SET_HINT(netif, hint) (etharp_cached_entry = (hint))
126 #endif /* LWIP_NETIF_HWADDRHINT */
128 static err_t update_arp_entry(struct netif *netif, ip_addr_t *ipaddr, struct eth_addr *ethaddr, u8_t flags);
131 /* Some checks, instead of etharp_init(): */
132 #if (LWIP_ARP && (ARP_TABLE_SIZE > 0x7f))
133 #error "ARP_TABLE_SIZE must fit in an s8_t, you have to reduce it in your lwipopts.h"
139 * Free a complete queue of etharp entries
141 * @param q a qeueue of etharp_q_entry's to free
144 free_etharp_q(struct etharp_q_entry *q)
146 struct etharp_q_entry *r;
147 LWIP_ASSERT("q != NULL", q != NULL);
148 LWIP_ASSERT("q->p != NULL", q->p != NULL);
152 LWIP_ASSERT("r->p != NULL", (r->p != NULL));
154 memp_free(MEMP_ARP_QUEUE, r);
157 #endif /* ARP_QUEUEING */
159 /** Clean up ARP table entries */
163 /* remove from SNMP ARP index tree */
164 snmp_delete_arpidx_tree(arp_table[i].netif, &arp_table[i].ipaddr);
166 /* and empty packet queue */
167 if (arp_table[i].q != NULL) {
168 /* remove all queued packets */
169 LWIP_DEBUGF(ETHARP_DEBUG, ("etharp_timer: freeing entry %"U16_F", packet queue %p.\n", (u16_t)i, (void *)(arp_table[i].q)));
170 free_etharp_q(arp_table[i].q);
171 arp_table[i].q = NULL;
173 #endif /* ARP_QUEUEING */
174 /* recycle entry for re-use */
175 arp_table[i].state = ETHARP_STATE_EMPTY;
176 #if ETHARP_SUPPORT_STATIC_ENTRIES
177 arp_table[i].static_entry = 0;
178 #endif /* ETHARP_SUPPORT_STATIC_ENTRIES */
180 /* for debugging, clean out the complete entry */
181 arp_table[i].ctime = 0;
183 arp_table[i].netif = NULL;
184 #endif /* LWIP_SNMP */
185 ip_addr_set_zero(&arp_table[i].ipaddr);
186 arp_table[i].ethaddr = ethzero;
187 #endif /* LWIP_DEBUG */
191 * Clears expired entries in the ARP table.
193 * This function should be called every ETHARP_TMR_INTERVAL milliseconds (5 seconds),
194 * in order to expire entries in the ARP table.
201 LWIP_DEBUGF(ETHARP_DEBUG, ("etharp_timer\n"));
202 /* remove expired entries from the ARP table */
203 for (i = 0; i < ARP_TABLE_SIZE; ++i) {
204 u8_t state = arp_table[i].state;
205 if (state != ETHARP_STATE_EMPTY
206 #if ETHARP_SUPPORT_STATIC_ENTRIES
207 && (arp_table[i].static_entry == 0)
208 #endif /* ETHARP_SUPPORT_STATIC_ENTRIES */
210 arp_table[i].ctime++;
211 if ((arp_table[i].ctime >= ARP_MAXAGE) ||
212 ((arp_table[i].state == ETHARP_STATE_PENDING) &&
213 (arp_table[i].ctime >= ARP_MAXPENDING))) {
214 /* pending or stable entry has become old! */
215 LWIP_DEBUGF(ETHARP_DEBUG, ("etharp_timer: expired %s entry %"U16_F".\n",
216 arp_table[i].state == ETHARP_STATE_STABLE ? "stable" : "pending", (u16_t)i));
217 /* clean up entries that have just been expired */
221 /* still pending entry? (not expired) */
222 if (arp_table[i].state == ETHARP_STATE_PENDING) {
223 /* resend an ARP query here? */
225 #endif /* ARP_QUEUEING */
231 * Search the ARP table for a matching or new entry.
233 * If an IP address is given, return a pending or stable ARP entry that matches
234 * the address. If no match is found, create a new entry with this address set,
235 * but in state ETHARP_EMPTY. The caller must check and possibly change the
236 * state of the returned entry.
238 * If ipaddr is NULL, return a initialized new entry in state ETHARP_EMPTY.
240 * In all cases, attempt to create new entries from an empty entry. If no
241 * empty entries are available and ETHARP_FLAG_TRY_HARD flag is set, recycle
242 * old entries. Heuristic choose the least important entry for recycling.
244 * @param ipaddr IP address to find in ARP cache, or to add if not found.
245 * @param flags @see definition of ETHARP_FLAG_*
246 * @param netif netif related to this address (used for NETIF_HWADDRHINT)
248 * @return The ARP entry index that matched or is created, ERR_MEM if no
249 * entry is found or could be recycled.
252 find_entry(ip_addr_t *ipaddr, u8_t flags)
254 s8_t old_pending = ARP_TABLE_SIZE, old_stable = ARP_TABLE_SIZE;
255 s8_t empty = ARP_TABLE_SIZE;
256 u8_t i = 0, age_pending = 0, age_stable = 0;
258 /* oldest entry with packets on queue */
259 s8_t old_queue = ARP_TABLE_SIZE;
262 #endif /* ARP_QUEUEING */
265 * a) do a search through the cache, remember candidates
266 * b) select candidate entry
267 * c) create new entry
270 /* a) in a single search sweep, do all of this
271 * 1) remember the first empty entry (if any)
272 * 2) remember the oldest stable entry (if any)
273 * 3) remember the oldest pending entry without queued packets (if any)
274 * 4) remember the oldest pending entry with queued packets (if any)
275 * 5) search for a matching IP entry, either pending or stable
276 * until 5 matches, or all entries are searched for.
279 for (i = 0; i < ARP_TABLE_SIZE; ++i) {
280 u8_t state = arp_table[i].state;
281 /* no empty entry found yet and now we do find one? */
282 if ((empty == ARP_TABLE_SIZE) && (state == ETHARP_STATE_EMPTY)) {
283 LWIP_DEBUGF(ETHARP_DEBUG, ("find_entry: found empty entry %"U16_F"\n", (u16_t)i));
284 /* remember first empty entry */
286 } else if (state != ETHARP_STATE_EMPTY) {
287 LWIP_ASSERT("state == ETHARP_STATE_PENDING || state == ETHARP_STATE_STABLE",
288 state == ETHARP_STATE_PENDING || state == ETHARP_STATE_STABLE);
289 /* if given, does IP address match IP address in ARP entry? */
290 if (ipaddr && ip_addr_cmp(ipaddr, &arp_table[i].ipaddr)) {
291 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("find_entry: found matching entry %"U16_F"\n", (u16_t)i));
292 /* found exact IP address match, simply bail out */
296 if (state == ETHARP_STATE_PENDING) {
297 /* pending with queued packets? */
299 if (arp_table[i].q != NULL) {
300 if (arp_table[i].ctime >= age_queue) {
302 age_queue = arp_table[i].ctime;
305 #endif /* ARP_QUEUEING */
306 /* pending without queued packets? */
308 if (arp_table[i].ctime >= age_pending) {
310 age_pending = arp_table[i].ctime;
314 } else if (state == ETHARP_STATE_STABLE) {
315 #if ETHARP_SUPPORT_STATIC_ENTRIES
316 /* don't record old_stable for static entries since they never expire */
317 if (arp_table[i].static_entry == 0)
318 #endif /* ETHARP_SUPPORT_STATIC_ENTRIES */
320 /* remember entry with oldest stable entry in oldest, its age in maxtime */
321 if (arp_table[i].ctime >= age_stable) {
323 age_stable = arp_table[i].ctime;
329 /* { we have no match } => try to create a new entry */
331 /* don't create new entry, only search? */
332 if (((flags & ETHARP_FLAG_FIND_ONLY) != 0) ||
333 /* or no empty entry found and not allowed to recycle? */
334 ((empty == ARP_TABLE_SIZE) && ((flags & ETHARP_FLAG_TRY_HARD) == 0))) {
335 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("find_entry: no empty entry found and not allowed to recycle\n"));
336 return (s8_t)ERR_MEM;
339 /* b) choose the least destructive entry to recycle:
341 * 2) oldest stable entry
342 * 3) oldest pending entry without queued packets
343 * 4) oldest pending entry with queued packets
345 * { ETHARP_FLAG_TRY_HARD is set at this point }
348 /* 1) empty entry available? */
349 if (empty < ARP_TABLE_SIZE) {
351 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("find_entry: selecting empty entry %"U16_F"\n", (u16_t)i));
353 /* 2) found recyclable stable entry? */
354 if (old_stable < ARP_TABLE_SIZE) {
355 /* recycle oldest stable*/
357 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("find_entry: selecting oldest stable entry %"U16_F"\n", (u16_t)i));
359 /* no queued packets should exist on stable entries */
360 LWIP_ASSERT("arp_table[i].q == NULL", arp_table[i].q == NULL);
361 #endif /* ARP_QUEUEING */
362 /* 3) found recyclable pending entry without queued packets? */
363 } else if (old_pending < ARP_TABLE_SIZE) {
364 /* recycle oldest pending */
366 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("find_entry: selecting oldest pending entry %"U16_F" (without queue)\n", (u16_t)i));
368 /* 4) found recyclable pending entry with queued packets? */
369 } else if (old_queue < ARP_TABLE_SIZE) {
370 /* recycle oldest pending (queued packets are free in free_entry) */
372 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("find_entry: selecting oldest pending entry %"U16_F", freeing packet queue %p\n", (u16_t)i, (void *)(arp_table[i].q)));
373 #endif /* ARP_QUEUEING */
374 /* no empty or recyclable entries found */
376 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("find_entry: no empty or recyclable entries found\n"));
377 return (s8_t)ERR_MEM;
380 /* { empty or recyclable entry found } */
381 LWIP_ASSERT("i < ARP_TABLE_SIZE", i < ARP_TABLE_SIZE);
385 LWIP_ASSERT("i < ARP_TABLE_SIZE", i < ARP_TABLE_SIZE);
386 LWIP_ASSERT("arp_table[i].state == ETHARP_STATE_EMPTY",
387 arp_table[i].state == ETHARP_STATE_EMPTY);
389 /* IP address given? */
390 if (ipaddr != NULL) {
392 ip_addr_copy(arp_table[i].ipaddr, *ipaddr);
394 arp_table[i].ctime = 0;
395 #if ETHARP_SUPPORT_STATIC_ENTRIES
396 arp_table[i].static_entry = 0;
397 #endif /* ETHARP_SUPPORT_STATIC_ENTRIES */
402 * Send an IP packet on the network using netif->linkoutput
403 * The ethernet header is filled in before sending.
405 * @params netif the lwIP network interface on which to send the packet
406 * @params p the packet to send, p->payload pointing to the (uninitialized) ethernet header
407 * @params src the source MAC address to be copied into the ethernet header
408 * @params dst the destination MAC address to be copied into the ethernet header
409 * @return ERR_OK if the packet was sent, any other err_t on failure
412 etharp_send_ip(struct netif *netif, struct pbuf *p, struct eth_addr *src, struct eth_addr *dst)
414 struct eth_hdr *ethhdr = (struct eth_hdr *)p->payload;
416 LWIP_ASSERT("netif->hwaddr_len must be the same as ETHARP_HWADDR_LEN for etharp!",
417 (netif->hwaddr_len == ETHARP_HWADDR_LEN));
418 ETHADDR32_COPY(ðhdr->dest, dst);
419 ETHADDR16_COPY(ðhdr->src, src);
420 ethhdr->type = PP_HTONS(ETHTYPE_IP);
421 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_send_ip: sending packet %p\n", (void *)p));
422 /* send the packet */
423 return netif->linkoutput(netif, p);
427 * Update (or insert) a IP/MAC address pair in the ARP cache.
429 * If a pending entry is resolved, any queued packets will be sent
432 * @param netif netif related to this entry (used for NETIF_ADDRHINT)
433 * @param ipaddr IP address of the inserted ARP entry.
434 * @param ethaddr Ethernet address of the inserted ARP entry.
435 * @param flags @see definition of ETHARP_FLAG_*
438 * - ERR_OK Succesfully updated ARP cache.
439 * - ERR_MEM If we could not add a new ARP entry when ETHARP_FLAG_TRY_HARD was set.
440 * - ERR_ARG Non-unicast address given, those will not appear in ARP cache.
445 update_arp_entry(struct netif *netif, ip_addr_t *ipaddr, struct eth_addr *ethaddr, u8_t flags)
448 LWIP_ASSERT("netif->hwaddr_len == ETHARP_HWADDR_LEN", netif->hwaddr_len == ETHARP_HWADDR_LEN);
449 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("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",
450 ip4_addr1_16(ipaddr), ip4_addr2_16(ipaddr), ip4_addr3_16(ipaddr), ip4_addr4_16(ipaddr),
451 ethaddr->addr[0], ethaddr->addr[1], ethaddr->addr[2],
452 ethaddr->addr[3], ethaddr->addr[4], ethaddr->addr[5]));
453 /* non-unicast address? */
454 if (ip_addr_isany(ipaddr) ||
455 ip_addr_isbroadcast(ipaddr, netif) ||
456 ip_addr_ismulticast(ipaddr)) {
457 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("update_arp_entry: will not add non-unicast IP address to ARP cache\n"));
460 /* find or create ARP entry */
461 i = find_entry(ipaddr, flags);
462 /* bail out if no entry could be found */
467 #if ETHARP_SUPPORT_STATIC_ENTRIES
468 if (flags & ETHARP_FLAG_STATIC_ENTRY) {
469 /* record static type */
470 arp_table[i].static_entry = 1;
472 #endif /* ETHARP_SUPPORT_STATIC_ENTRIES */
475 arp_table[i].state = ETHARP_STATE_STABLE;
478 /* record network interface */
479 arp_table[i].netif = netif;
480 #endif /* LWIP_SNMP */
481 /* insert in SNMP ARP index tree */
482 snmp_insert_arpidx_tree(netif, &arp_table[i].ipaddr);
484 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("update_arp_entry: updating stable entry %"S16_F"\n", (s16_t)i));
486 ETHADDR32_COPY(&arp_table[i].ethaddr, ethaddr);
487 /* reset time stamp */
488 arp_table[i].ctime = 0;
490 /* this is where we will send out queued packets! */
491 while (arp_table[i].q != NULL) {
493 /* remember remainder of queue */
494 struct etharp_q_entry *q = arp_table[i].q;
495 /* pop first item off the queue */
496 arp_table[i].q = q->next;
497 /* get the packet pointer */
499 /* now queue entry can be freed */
500 memp_free(MEMP_ARP_QUEUE, q);
501 /* send the queued IP packet */
502 etharp_send_ip(netif, p, (struct eth_addr*)(netif->hwaddr), ethaddr);
503 /* free the queued IP packet */
506 #endif /* ARP_QUEUEING */
510 #if ETHARP_SUPPORT_STATIC_ENTRIES
511 /** Add a new static entry to the ARP table. If an entry exists for the
512 * specified IP address, this entry is overwritten.
513 * If packets are queued for the specified IP address, they are sent out.
515 * @param ipaddr IP address for the new static entry
516 * @param ethaddr ethernet address for the new static entry
517 * @return @see return values of etharp_add_static_entry
520 etharp_add_static_entry(ip_addr_t *ipaddr, struct eth_addr *ethaddr)
523 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",
524 ip4_addr1_16(ipaddr), ip4_addr2_16(ipaddr), ip4_addr3_16(ipaddr), ip4_addr4_16(ipaddr),
525 ethaddr->addr[0], ethaddr->addr[1], ethaddr->addr[2],
526 ethaddr->addr[3], ethaddr->addr[4], ethaddr->addr[5]));
528 netif = ip_route(ipaddr);
533 return update_arp_entry(netif, ipaddr, ethaddr, ETHARP_FLAG_TRY_HARD | ETHARP_FLAG_STATIC_ENTRY);
536 /** Remove a static entry from the ARP table previously added with a call to
537 * etharp_add_static_entry.
539 * @param ipaddr IP address of the static entry to remove
540 * @return ERR_OK: entry removed
541 * ERR_MEM: entry wasn't found
542 * ERR_ARG: entry wasn't a static entry but a dynamic one
545 etharp_remove_static_entry(ip_addr_t *ipaddr)
548 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_remove_static_entry: %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
549 ip4_addr1_16(ipaddr), ip4_addr2_16(ipaddr), ip4_addr3_16(ipaddr), ip4_addr4_16(ipaddr)));
551 /* find or create ARP entry */
552 i = find_entry(ipaddr, ETHARP_FLAG_FIND_ONLY);
553 /* bail out if no entry could be found */
558 if ((arp_table[i].state != ETHARP_STATE_STABLE) ||
559 (arp_table[i].static_entry == 0)) {
560 /* entry wasn't a static entry, cannot remove it */
563 /* entry found, free it */
567 #endif /* ETHARP_SUPPORT_STATIC_ENTRIES */
570 * Finds (stable) ethernet/IP address pair from ARP table
571 * using interface and IP address index.
572 * @note the addresses in the ARP table are in network order!
574 * @param netif points to interface index
575 * @param ipaddr points to the (network order) IP address index
576 * @param eth_ret points to return pointer
577 * @param ip_ret points to return pointer
578 * @return table index if found, -1 otherwise
581 etharp_find_addr(struct netif *netif, ip_addr_t *ipaddr,
582 struct eth_addr **eth_ret, ip_addr_t **ip_ret)
586 LWIP_ASSERT("eth_ret != NULL && ip_ret != NULL",
587 eth_ret != NULL && ip_ret != NULL);
589 LWIP_UNUSED_ARG(netif);
591 i = find_entry(ipaddr, ETHARP_FLAG_FIND_ONLY);
592 if((i >= 0) && arp_table[i].state == ETHARP_STATE_STABLE) {
593 *eth_ret = &arp_table[i].ethaddr;
594 *ip_ret = &arp_table[i].ipaddr;
600 #if ETHARP_TRUST_IP_MAC
602 * Updates the ARP table using the given IP packet.
604 * Uses the incoming IP packet's source address to update the
605 * ARP cache for the local network. The function does not alter
606 * or free the packet. This function must be called before the
607 * packet p is passed to the IP layer.
609 * @param netif The lwIP network interface on which the IP packet pbuf arrived.
610 * @param p The IP packet that arrived on netif.
617 etharp_ip_input(struct netif *netif, struct pbuf *p)
619 struct eth_hdr *ethhdr;
620 struct ip_hdr *iphdr;
621 LWIP_ERROR("netif != NULL", (netif != NULL), return;);
623 /* Only insert an entry if the source IP address of the
624 incoming IP packet comes from a host on the local network. */
625 ethhdr = (struct eth_hdr *)p->payload;
626 iphdr = (struct ip_hdr *)((u8_t*)ethhdr + SIZEOF_ETH_HDR);
627 #if ETHARP_SUPPORT_VLAN
628 if (ethhdr->type == ETHTYPE_VLAN) {
629 iphdr = (struct ip_hdr *)((u8_t*)ethhdr + SIZEOF_ETH_HDR + SIZEOF_VLAN_HDR);
631 #endif /* ETHARP_SUPPORT_VLAN */
633 /* source is not on the local network? */
634 if (!ip_addr_netcmp(&(iphdr->src), &(netif->ip_addr), &(netif->netmask))) {
639 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_ip_input: updating ETHARP table.\n"));
640 /* update the source IP address in the cache, if present */
641 /* @todo We could use ETHARP_FLAG_TRY_HARD if we think we are going to talk
642 * back soon (for example, if the destination IP address is ours. */
643 update_arp_entry(netif, &(iphdr->src), &(ethhdr->src), ETHARP_FLAG_FIND_ONLY);
645 #endif /* ETHARP_TRUST_IP_MAC */
648 * Responds to ARP requests to us. Upon ARP replies to us, add entry to cache
649 * send out queued IP packets. Updates cache with snooped address pairs.
651 * Should be called for incoming ARP packets. The pbuf in the argument
652 * is freed by this function.
654 * @param netif The lwIP network interface on which the ARP packet pbuf arrived.
655 * @param ethaddr Ethernet address of netif.
656 * @param p The ARP packet that arrived on netif. Is freed by this function.
663 etharp_arp_input(struct netif *netif, struct eth_addr *ethaddr, struct pbuf *p)
665 struct etharp_hdr *hdr;
666 struct eth_hdr *ethhdr;
667 /* these are aligned properly, whereas the ARP header fields might not be */
668 ip_addr_t sipaddr, dipaddr;
671 const u8_t * ethdst_hwaddr;
672 #endif /* LWIP_AUTOIP */
674 LWIP_ERROR("netif != NULL", (netif != NULL), return;);
676 /* drop short ARP packets: we have to check for p->len instead of p->tot_len here
677 since a struct etharp_hdr is pointed to p->payload, so it musn't be chained! */
678 if (p->len < SIZEOF_ETHARP_PACKET) {
679 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING,
680 ("etharp_arp_input: packet dropped, too short (%"S16_F"/%"S16_F")\n", p->tot_len,
681 (s16_t)SIZEOF_ETHARP_PACKET));
682 ETHARP_STATS_INC(etharp.lenerr);
683 ETHARP_STATS_INC(etharp.drop);
688 ethhdr = (struct eth_hdr *)p->payload;
689 hdr = (struct etharp_hdr *)((u8_t*)ethhdr + SIZEOF_ETH_HDR);
690 #if ETHARP_SUPPORT_VLAN
691 if (ethhdr->type == ETHTYPE_VLAN) {
692 hdr = (struct etharp_hdr *)(((u8_t*)ethhdr) + SIZEOF_ETH_HDR + SIZEOF_VLAN_HDR);
694 #endif /* ETHARP_SUPPORT_VLAN */
696 /* RFC 826 "Packet Reception": */
697 if ((hdr->hwtype != PP_HTONS(HWTYPE_ETHERNET)) ||
698 (hdr->hwlen != ETHARP_HWADDR_LEN) ||
699 (hdr->protolen != sizeof(ip_addr_t)) ||
700 (hdr->proto != PP_HTONS(ETHTYPE_IP)) ||
701 (ethhdr->type != PP_HTONS(ETHTYPE_ARP))) {
702 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING,
703 ("etharp_arp_input: packet dropped, wrong hw type, hwlen, proto, protolen or ethernet type (%"U16_F"/%"U16_F"/%"U16_F"/%"U16_F"/%"U16_F")\n",
704 hdr->hwtype, hdr->hwlen, hdr->proto, hdr->protolen, ethhdr->type));
705 ETHARP_STATS_INC(etharp.proterr);
706 ETHARP_STATS_INC(etharp.drop);
710 ETHARP_STATS_INC(etharp.recv);
713 /* We have to check if a host already has configured our random
714 * created link local address and continously check if there is
715 * a host with this IP-address so we can detect collisions */
716 autoip_arp_reply(netif, hdr);
717 #endif /* LWIP_AUTOIP */
719 /* Copy struct ip_addr2 to aligned ip_addr, to support compilers without
720 * structure packing (not using structure copy which breaks strict-aliasing rules). */
721 IPADDR2_COPY(&sipaddr, &hdr->sipaddr);
722 IPADDR2_COPY(&dipaddr, &hdr->dipaddr);
724 /* this interface is not configured? */
725 if (ip_addr_isany(&netif->ip_addr)) {
728 /* ARP packet directed to us? */
729 for_us = (u8_t)ip_addr_cmp(&dipaddr, &(netif->ip_addr));
732 /* ARP message directed to us?
733 -> add IP address in ARP cache; assume requester wants to talk to us,
734 can result in directly sending the queued packets for this host.
735 ARP message not directed to us?
736 -> update the source IP address in the cache, if present */
737 update_arp_entry(netif, &sipaddr, &(hdr->shwaddr),
738 for_us ? ETHARP_FLAG_TRY_HARD : ETHARP_FLAG_FIND_ONLY);
740 /* now act on the message itself */
741 switch (hdr->opcode) {
743 case PP_HTONS(ARP_REQUEST):
744 /* ARP request. If it asked for our address, we send out a
745 * reply. In any case, we time-stamp any existing ARP entry,
746 * and possiby send out an IP packet that was queued on it. */
748 LWIP_DEBUGF (ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_arp_input: incoming ARP request\n"));
749 /* ARP request for our address? */
752 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_arp_input: replying to ARP request for our IP address\n"));
753 /* Re-use pbuf to send ARP reply.
754 Since we are re-using an existing pbuf, we can't call etharp_raw since
755 that would allocate a new pbuf. */
756 hdr->opcode = htons(ARP_REPLY);
758 IPADDR2_COPY(&hdr->dipaddr, &hdr->sipaddr);
759 IPADDR2_COPY(&hdr->sipaddr, &netif->ip_addr);
761 LWIP_ASSERT("netif->hwaddr_len must be the same as ETHARP_HWADDR_LEN for etharp!",
762 (netif->hwaddr_len == ETHARP_HWADDR_LEN));
764 /* If we are using Link-Local, all ARP packets that contain a Link-Local
765 * 'sender IP address' MUST be sent using link-layer broadcast instead of
766 * link-layer unicast. (See RFC3927 Section 2.5, last paragraph) */
767 ethdst_hwaddr = ip_addr_islinklocal(&netif->ip_addr) ? (u8_t*)(ethbroadcast.addr) : hdr->shwaddr.addr;
768 #endif /* LWIP_AUTOIP */
770 ETHADDR16_COPY(&hdr->dhwaddr, &hdr->shwaddr);
772 ETHADDR16_COPY(ðhdr->dest, ethdst_hwaddr);
773 #else /* LWIP_AUTOIP */
774 ETHADDR16_COPY(ðhdr->dest, &hdr->shwaddr);
775 #endif /* LWIP_AUTOIP */
776 ETHADDR16_COPY(&hdr->shwaddr, ethaddr);
777 ETHADDR16_COPY(ðhdr->src, ethaddr);
779 /* hwtype, hwaddr_len, proto, protolen and the type in the ethernet header
780 are already correct, we tested that before */
782 /* return ARP reply */
783 netif->linkoutput(netif, p);
784 /* we are not configured? */
785 } else if (ip_addr_isany(&netif->ip_addr)) {
786 /* { for_us == 0 and netif->ip_addr.addr == 0 } */
787 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_arp_input: we are unconfigured, ARP request ignored.\n"));
788 /* request was not directed to us */
790 /* { for_us == 0 and netif->ip_addr.addr != 0 } */
791 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_arp_input: ARP request was not for us.\n"));
794 case PP_HTONS(ARP_REPLY):
795 /* ARP reply. We already updated the ARP cache earlier. */
796 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_arp_input: incoming ARP reply\n"));
797 #if (LWIP_DHCP && DHCP_DOES_ARP_CHECK)
798 /* DHCP wants to know about ARP replies from any host with an
799 * IP address also offered to us by the DHCP server. We do not
800 * want to take a duplicate IP address on a single network.
801 * @todo How should we handle redundant (fail-over) interfaces? */
802 dhcp_arp_reply(netif, &sipaddr);
803 #endif /* (LWIP_DHCP && DHCP_DOES_ARP_CHECK) */
806 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_arp_input: ARP unknown opcode type %"S16_F"\n", htons(hdr->opcode)));
807 ETHARP_STATS_INC(etharp.err);
810 /* free ARP packet */
815 * Resolve and fill-in Ethernet address header for outgoing IP packet.
817 * For IP multicast and broadcast, corresponding Ethernet addresses
818 * are selected and the packet is transmitted on the link.
820 * For unicast addresses, the packet is submitted to etharp_query(). In
821 * case the IP address is outside the local network, the IP address of
822 * the gateway is used.
824 * @param netif The lwIP network interface which the IP packet will be sent on.
825 * @param q The pbuf(s) containing the IP packet to be sent.
826 * @param ipaddr The IP address of the packet destination.
829 * - ERR_RTE No route to destination (no gateway to external networks),
830 * or the return type of either etharp_query() or etharp_send_ip().
833 etharp_output(struct netif *netif, struct pbuf *q, ip_addr_t *ipaddr)
835 struct eth_addr *dest, mcastaddr;
837 /* make room for Ethernet header - should not fail */
838 if (pbuf_header(q, sizeof(struct eth_hdr)) != 0) {
840 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS,
841 ("etharp_output: could not allocate room for header.\n"));
842 LINK_STATS_INC(link.lenerr);
846 /* assume unresolved Ethernet address */
848 /* Determine on destination hardware address. Broadcasts and multicasts
849 * are special, other IP addresses are looked up in the ARP table. */
851 /* broadcast destination IP address? */
852 if (ip_addr_isbroadcast(ipaddr, netif)) {
853 /* broadcast on Ethernet also */
854 dest = (struct eth_addr *)ðbroadcast;
855 /* multicast destination IP address? */
856 } else if (ip_addr_ismulticast(ipaddr)) {
857 /* Hash IP multicast address to MAC address.*/
858 mcastaddr.addr[0] = 0x01;
859 mcastaddr.addr[1] = 0x00;
860 mcastaddr.addr[2] = 0x5e;
861 mcastaddr.addr[3] = ip4_addr2(ipaddr) & 0x7f;
862 mcastaddr.addr[4] = ip4_addr3(ipaddr);
863 mcastaddr.addr[5] = ip4_addr4(ipaddr);
864 /* destination Ethernet address is multicast */
866 /* unicast destination IP address? */
868 /* outside local network? */
869 if (!ip_addr_netcmp(ipaddr, &(netif->ip_addr), &(netif->netmask)) &&
870 !ip_addr_islinklocal(ipaddr)) {
871 /* interface has default gateway? */
872 if (!ip_addr_isany(&netif->gw)) {
873 /* send to hardware address of default gateway IP address */
874 ipaddr = &(netif->gw);
875 /* no default gateway available */
877 /* no route to destination error (default gateway missing) */
881 #if LWIP_NETIF_HWADDRHINT
882 if (netif->addr_hint != NULL) {
883 /* per-pcb cached entry was given */
884 u8_t etharp_cached_entry = *(netif->addr_hint);
885 if (etharp_cached_entry < ARP_TABLE_SIZE) {
886 #endif /* LWIP_NETIF_HWADDRHINT */
887 if ((arp_table[etharp_cached_entry].state == ETHARP_STATE_STABLE) &&
888 (ip_addr_cmp(ipaddr, &arp_table[etharp_cached_entry].ipaddr))) {
889 /* the per-pcb-cached entry is stable and the right one! */
890 ETHARP_STATS_INC(etharp.cachehit);
891 return etharp_send_ip(netif, q, (struct eth_addr*)(netif->hwaddr),
892 &arp_table[etharp_cached_entry].ethaddr);
894 #if LWIP_NETIF_HWADDRHINT
897 #endif /* LWIP_NETIF_HWADDRHINT */
898 /* queue on destination Ethernet address belonging to ipaddr */
899 return etharp_query(netif, ipaddr, q);
902 /* continuation for multicast/broadcast destinations */
903 /* obtain source Ethernet address of the given interface */
904 /* send packet directly on the link */
905 return etharp_send_ip(netif, q, (struct eth_addr*)(netif->hwaddr), dest);
909 * Send an ARP request for the given IP address and/or queue a packet.
911 * If the IP address was not yet in the cache, a pending ARP cache entry
912 * is added and an ARP request is sent for the given address. The packet
913 * is queued on this entry.
915 * If the IP address was already pending in the cache, a new ARP request
916 * is sent for the given address. The packet is queued on this entry.
918 * If the IP address was already stable in the cache, and a packet is
919 * given, it is directly sent and no ARP request is sent out.
921 * If the IP address was already stable in the cache, and no packet is
922 * given, an ARP request is sent out.
924 * @param netif The lwIP network interface on which ipaddr
925 * must be queried for.
926 * @param ipaddr The IP address to be resolved.
927 * @param q If non-NULL, a pbuf that must be delivered to the IP address.
928 * q is not freed by this function.
930 * @note q must only be ONE packet, not a packet queue!
933 * - ERR_BUF Could not make room for Ethernet header.
934 * - ERR_MEM Hardware address unknown, and no more ARP entries available
935 * to query for address or queue the packet.
936 * - ERR_MEM Could not queue packet due to memory shortage.
937 * - ERR_RTE No route to destination (no gateway to external networks).
938 * - ERR_ARG Non-unicast address given, those will not appear in ARP cache.
942 etharp_query(struct netif *netif, ip_addr_t *ipaddr, struct pbuf *q)
944 struct eth_addr * srcaddr = (struct eth_addr *)netif->hwaddr;
945 err_t result = ERR_MEM;
946 s8_t i; /* ARP entry index */
948 /* non-unicast address? */
949 if (ip_addr_isbroadcast(ipaddr, netif) ||
950 ip_addr_ismulticast(ipaddr) ||
951 ip_addr_isany(ipaddr)) {
952 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: will not add non-unicast IP address to ARP cache\n"));
956 /* find entry in ARP cache, ask to create entry if queueing packet */
957 i = find_entry(ipaddr, ETHARP_FLAG_TRY_HARD);
959 /* could not find or create entry? */
961 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: could not create ARP entry\n"));
963 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: packet dropped\n"));
964 ETHARP_STATS_INC(etharp.memerr);
969 /* mark a fresh entry as pending (we just sent a request) */
970 if (arp_table[i].state == ETHARP_STATE_EMPTY) {
971 arp_table[i].state = ETHARP_STATE_PENDING;
974 /* { i is either a STABLE or (new or existing) PENDING entry } */
975 LWIP_ASSERT("arp_table[i].state == PENDING or STABLE",
976 ((arp_table[i].state == ETHARP_STATE_PENDING) ||
977 (arp_table[i].state == ETHARP_STATE_STABLE)));
979 /* do we have a pending entry? or an implicit query request? */
980 if ((arp_table[i].state == ETHARP_STATE_PENDING) || (q == NULL)) {
981 /* try to resolve it; send out ARP request */
982 result = etharp_request(netif, ipaddr);
983 if (result != ERR_OK) {
984 /* ARP request couldn't be sent */
985 /* We don't re-send arp request in etharp_tmr, but we still queue packets,
986 since this failure could be temporary, and the next packet calling
987 etharp_query again could lead to sending the queued packets. */
995 LWIP_ASSERT("q != NULL", q != NULL);
997 if (arp_table[i].state == ETHARP_STATE_STABLE) {
998 /* we have a valid IP->Ethernet address mapping */
999 ETHARP_SET_HINT(netif, i);
1000 /* send the packet */
1001 result = etharp_send_ip(netif, q, srcaddr, &(arp_table[i].ethaddr));
1002 /* pending entry? (either just created or already pending */
1003 } else if (arp_table[i].state == ETHARP_STATE_PENDING) {
1004 #if ARP_QUEUEING /* queue the given q packet */
1006 int copy_needed = 0;
1007 /* IF q includes a PBUF_REF, PBUF_POOL or PBUF_RAM, we have no choice but
1008 * to copy the whole queue into a new PBUF_RAM (see bug #11400)
1009 * PBUF_ROMs can be left as they are, since ROM must not get changed. */
1012 LWIP_ASSERT("no packet queues allowed!", (p->len != p->tot_len) || (p->next == 0));
1013 if(p->type != PBUF_ROM) {
1020 /* copy the whole packet into new pbufs */
1021 p = pbuf_alloc(PBUF_RAW, p->tot_len, PBUF_RAM);
1023 if (pbuf_copy(p, q) != ERR_OK) {
1029 /* referencing the old pbuf is enough */
1033 /* packet could be taken over? */
1035 /* queue packet ... */
1036 struct etharp_q_entry *new_entry;
1037 /* allocate a new arp queue entry */
1038 new_entry = (struct etharp_q_entry *)memp_malloc(MEMP_ARP_QUEUE);
1039 if (new_entry != NULL) {
1040 new_entry->next = 0;
1042 if(arp_table[i].q != NULL) {
1043 /* queue was already existent, append the new entry to the end */
1044 struct etharp_q_entry *r;
1046 while (r->next != NULL) {
1049 r->next = new_entry;
1051 /* queue did not exist, first item in queue */
1052 arp_table[i].q = new_entry;
1054 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: queued packet %p on ARP entry %"S16_F"\n", (void *)q, (s16_t)i));
1057 /* the pool MEMP_ARP_QUEUE is empty */
1059 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));
1060 /* { result == ERR_MEM } through initialization */
1063 ETHARP_STATS_INC(etharp.memerr);
1064 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));
1065 /* { result == ERR_MEM } through initialization */
1067 #else /* ARP_QUEUEING */
1068 /* q && state == PENDING && ARP_QUEUEING == 0 => result = ERR_MEM */
1069 /* { result == ERR_MEM } through initialization */
1070 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: Ethernet destination address unknown, queueing disabled, packet %p dropped\n", (void *)q));
1071 #endif /* ARP_QUEUEING */
1077 * Send a raw ARP packet (opcode and all addresses can be modified)
1079 * @param netif the lwip network interface on which to send the ARP packet
1080 * @param ethsrc_addr the source MAC address for the ethernet header
1081 * @param ethdst_addr the destination MAC address for the ethernet header
1082 * @param hwsrc_addr the source MAC address for the ARP protocol header
1083 * @param ipsrc_addr the source IP address for the ARP protocol header
1084 * @param hwdst_addr the destination MAC address for the ARP protocol header
1085 * @param ipdst_addr the destination IP address for the ARP protocol header
1086 * @param opcode the type of the ARP packet
1087 * @return ERR_OK if the ARP packet has been sent
1088 * ERR_MEM if the ARP packet couldn't be allocated
1089 * any other err_t on failure
1093 #endif /* LWIP_AUTOIP */
1095 etharp_raw(struct netif *netif, const struct eth_addr *ethsrc_addr,
1096 const struct eth_addr *ethdst_addr,
1097 const struct eth_addr *hwsrc_addr, const ip_addr_t *ipsrc_addr,
1098 const struct eth_addr *hwdst_addr, const ip_addr_t *ipdst_addr,
1102 err_t result = ERR_OK;
1103 struct eth_hdr *ethhdr;
1104 struct etharp_hdr *hdr;
1106 const u8_t * ethdst_hwaddr;
1107 #endif /* LWIP_AUTOIP */
1109 /* allocate a pbuf for the outgoing ARP request packet */
1110 p = pbuf_alloc(PBUF_RAW, SIZEOF_ETHARP_PACKET, PBUF_RAM);
1111 /* could allocate a pbuf for an ARP request? */
1113 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS,
1114 ("etharp_raw: could not allocate pbuf for ARP request.\n"));
1115 ETHARP_STATS_INC(etharp.memerr);
1118 LWIP_ASSERT("check that first pbuf can hold struct etharp_hdr",
1119 (p->len >= SIZEOF_ETHARP_PACKET));
1121 ethhdr = (struct eth_hdr *)p->payload;
1122 hdr = (struct etharp_hdr *)((u8_t*)ethhdr + SIZEOF_ETH_HDR);
1123 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_raw: sending raw ARP packet.\n"));
1124 hdr->opcode = htons(opcode);
1126 LWIP_ASSERT("netif->hwaddr_len must be the same as ETHARP_HWADDR_LEN for etharp!",
1127 (netif->hwaddr_len == ETHARP_HWADDR_LEN));
1129 /* If we are using Link-Local, all ARP packets that contain a Link-Local
1130 * 'sender IP address' MUST be sent using link-layer broadcast instead of
1131 * link-layer unicast. (See RFC3927 Section 2.5, last paragraph) */
1132 ethdst_hwaddr = ip_addr_islinklocal(ipsrc_addr) ? (u8_t*)(ethbroadcast.addr) : ethdst_addr->addr;
1133 #endif /* LWIP_AUTOIP */
1134 /* Write the ARP MAC-Addresses */
1135 ETHADDR16_COPY(&hdr->shwaddr, hwsrc_addr);
1136 ETHADDR16_COPY(&hdr->dhwaddr, hwdst_addr);
1137 /* Write the Ethernet MAC-Addresses */
1139 ETHADDR16_COPY(ðhdr->dest, ethdst_hwaddr);
1140 #else /* LWIP_AUTOIP */
1141 ETHADDR16_COPY(ðhdr->dest, ethdst_addr);
1142 #endif /* LWIP_AUTOIP */
1143 ETHADDR16_COPY(ðhdr->src, ethsrc_addr);
1144 /* Copy struct ip_addr2 to aligned ip_addr, to support compilers without
1145 * structure packing. */
1146 IPADDR2_COPY(&hdr->sipaddr, ipsrc_addr);
1147 IPADDR2_COPY(&hdr->dipaddr, ipdst_addr);
1149 hdr->hwtype = PP_HTONS(HWTYPE_ETHERNET);
1150 hdr->proto = PP_HTONS(ETHTYPE_IP);
1151 /* set hwlen and protolen */
1152 hdr->hwlen = ETHARP_HWADDR_LEN;
1153 hdr->protolen = sizeof(ip_addr_t);
1155 ethhdr->type = PP_HTONS(ETHTYPE_ARP);
1156 /* send ARP query */
1157 result = netif->linkoutput(netif, p);
1158 ETHARP_STATS_INC(etharp.xmit);
1159 /* free ARP query packet */
1162 /* could not allocate pbuf for ARP request */
1168 * Send an ARP request packet asking for ipaddr.
1170 * @param netif the lwip network interface on which to send the request
1171 * @param ipaddr the IP address for which to ask
1172 * @return ERR_OK if the request has been sent
1173 * ERR_MEM if the ARP packet couldn't be allocated
1174 * any other err_t on failure
1177 etharp_request(struct netif *netif, ip_addr_t *ipaddr)
1179 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_request: sending ARP request.\n"));
1180 return etharp_raw(netif, (struct eth_addr *)netif->hwaddr, ðbroadcast,
1181 (struct eth_addr *)netif->hwaddr, &netif->ip_addr, ðzero,
1182 ipaddr, ARP_REQUEST);
1184 #endif /* LWIP_ARP */
1187 * Process received ethernet frames. Using this function instead of directly
1188 * calling ip_input and passing ARP frames through etharp in ethernetif_input,
1189 * the ARP cache is protected from concurrent access.
1191 * @param p the recevied packet, p->payload pointing to the ethernet header
1192 * @param netif the network interface on which the packet was received
1195 ethernet_input(struct pbuf *p, struct netif *netif)
1197 struct eth_hdr* ethhdr;
1200 /* points to packet payload, which starts with an Ethernet header */
1201 ethhdr = (struct eth_hdr *)p->payload;
1202 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE,
1203 ("ethernet_input: dest:%"X8_F":%"X8_F":%"X8_F":%"X8_F":%"X8_F":%"X8_F", src:%"X8_F":%"X8_F":%"X8_F":%"X8_F":%"X8_F":%"X8_F", type:%"X16_F"\n",
1204 (unsigned)ethhdr->dest.addr[0], (unsigned)ethhdr->dest.addr[1], (unsigned)ethhdr->dest.addr[2],
1205 (unsigned)ethhdr->dest.addr[3], (unsigned)ethhdr->dest.addr[4], (unsigned)ethhdr->dest.addr[5],
1206 (unsigned)ethhdr->src.addr[0], (unsigned)ethhdr->src.addr[1], (unsigned)ethhdr->src.addr[2],
1207 (unsigned)ethhdr->src.addr[3], (unsigned)ethhdr->src.addr[4], (unsigned)ethhdr->src.addr[5],
1208 (unsigned)htons(ethhdr->type)));
1210 type = ethhdr->type;
1211 #if ETHARP_SUPPORT_VLAN
1212 if (type == PP_HTONS(ETHTYPE_VLAN)) {
1213 struct eth_vlan_hdr *vlan = (struct eth_vlan_hdr*)(((char*)ethhdr) + SIZEOF_ETH_HDR);
1214 #ifdef ETHARP_VLAN_CHECK /* if not, allow all VLANs */
1215 if (VLAN_ID(vlan) != ETHARP_VLAN_CHECK) {
1216 /* silently ignore this packet: not for our VLAN */
1220 #endif /* ETHARP_VLAN_CHECK */
1223 #endif /* ETHARP_SUPPORT_VLAN */
1225 #if LWIP_ARP_FILTER_NETIF
1226 netif = LWIP_ARP_FILTER_NETIF_FN(p, netif, htons(type));
1227 #endif /* LWIP_ARP_FILTER_NETIF*/
1232 case PP_HTONS(ETHTYPE_IP):
1233 if (!(netif->flags & NETIF_FLAG_ETHARP)) {
1234 goto free_and_return;
1236 #if ETHARP_TRUST_IP_MAC
1237 /* update ARP table */
1238 etharp_ip_input(netif, p);
1239 #endif /* ETHARP_TRUST_IP_MAC */
1240 /* skip Ethernet header */
1241 if(pbuf_header(p, -(s16_t)SIZEOF_ETH_HDR)) {
1242 LWIP_ASSERT("Can't move over header in packet", 0);
1243 goto free_and_return;
1245 /* pass to IP layer */
1250 case PP_HTONS(ETHTYPE_ARP):
1251 if (!(netif->flags & NETIF_FLAG_ETHARP)) {
1252 goto free_and_return;
1254 /* pass p to ARP module */
1255 etharp_arp_input(netif, (struct eth_addr*)(netif->hwaddr), p);
1257 #endif /* LWIP_ARP */
1259 case PP_HTONS(ETHTYPE_PPPOEDISC): /* PPP Over Ethernet Discovery Stage */
1260 pppoe_disc_input(netif, p);
1263 case PP_HTONS(ETHTYPE_PPPOE): /* PPP Over Ethernet Session Stage */
1264 pppoe_data_input(netif, p);
1266 #endif /* PPPOE_SUPPORT */
1269 ETHARP_STATS_INC(etharp.proterr);
1270 ETHARP_STATS_INC(etharp.drop);
1271 goto free_and_return;
1274 /* This means the pbuf is freed or consumed,
1275 so the caller doesn't have to free it again */
1282 #endif /* LWIP_ARP || LWIP_ETHERNET */