source: UsbWattMeter/trunk/lwip-1.4.1/src/netif/etharp.c@ 164

Last change on this file since 164 was 164, checked in by coas-nagasima, 6 years ago

TOPPERS/ECNLサンプルアプリ「USB充電器電力計」を追加

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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_ARP || LWIP_ETHERNET
49
50#include "lwip/ip_addr.h"
51#include "lwip/def.h"
52#include "lwip/ip.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"
58
59#if PPPOE_SUPPORT
60#include "netif/ppp_oe.h"
61#endif /* PPPOE_SUPPORT */
62
63#include <string.h>
64
65const struct eth_addr ethbroadcast = {{0xff,0xff,0xff,0xff,0xff,0xff}};
66const struct eth_addr ethzero = {{0,0,0,0,0,0}};
67
68/** The 24-bit IANA multicast OUI is 01-00-5e: */
69#define LL_MULTICAST_ADDR_0 0x01
70#define LL_MULTICAST_ADDR_1 0x00
71#define LL_MULTICAST_ADDR_2 0x5e
72
73#if LWIP_ARP /* don't build if not configured for use in lwipopts.h */
74
75/** the time an ARP entry stays valid after its last update,
76 * for ARP_TMR_INTERVAL = 5000, this is
77 * (240 * 5) seconds = 20 minutes.
78 */
79#define ARP_MAXAGE 240
80/** Re-request a used ARP entry 1 minute before it would expire to prevent
81 * breaking a steadily used connection because the ARP entry timed out. */
82#define ARP_AGE_REREQUEST_USED (ARP_MAXAGE - 12)
83
84/** the time an ARP entry stays pending after first request,
85 * for ARP_TMR_INTERVAL = 5000, this is
86 * (2 * 5) seconds = 10 seconds.
87 *
88 * @internal Keep this number at least 2, otherwise it might
89 * run out instantly if the timeout occurs directly after a request.
90 */
91#define ARP_MAXPENDING 2
92
93#define HWTYPE_ETHERNET 1
94
95enum etharp_state {
96 ETHARP_STATE_EMPTY = 0,
97 ETHARP_STATE_PENDING,
98 ETHARP_STATE_STABLE,
99 ETHARP_STATE_STABLE_REREQUESTING
100#if ETHARP_SUPPORT_STATIC_ENTRIES
101 ,ETHARP_STATE_STATIC
102#endif /* ETHARP_SUPPORT_STATIC_ENTRIES */
103};
104
105struct etharp_entry {
106#if ARP_QUEUEING
107 /** Pointer to queue of pending outgoing packets on this ARP entry. */
108 struct etharp_q_entry *q;
109#else /* ARP_QUEUEING */
110 /** Pointer to a single pending outgoing packet on this ARP entry. */
111 struct pbuf *q;
112#endif /* ARP_QUEUEING */
113 ip_addr_t ipaddr;
114 struct netif *netif;
115 struct eth_addr ethaddr;
116 u8_t state;
117 u8_t ctime;
118};
119
120static struct etharp_entry arp_table[ARP_TABLE_SIZE];
121
122#if !LWIP_NETIF_HWADDRHINT
123static u8_t etharp_cached_entry;
124#endif /* !LWIP_NETIF_HWADDRHINT */
125
126/** Try hard to create a new entry - we want the IP address to appear in
127 the cache (even if this means removing an active entry or so). */
128#define ETHARP_FLAG_TRY_HARD 1
129#define ETHARP_FLAG_FIND_ONLY 2
130#if ETHARP_SUPPORT_STATIC_ENTRIES
131#define ETHARP_FLAG_STATIC_ENTRY 4
132#endif /* ETHARP_SUPPORT_STATIC_ENTRIES */
133
134#if LWIP_NETIF_HWADDRHINT
135#define ETHARP_SET_HINT(netif, hint) if (((netif) != NULL) && ((netif)->addr_hint != NULL)) \
136 *((netif)->addr_hint) = (hint);
137#else /* LWIP_NETIF_HWADDRHINT */
138#define ETHARP_SET_HINT(netif, hint) (etharp_cached_entry = (hint))
139#endif /* LWIP_NETIF_HWADDRHINT */
140
141
142/* Some checks, instead of etharp_init(): */
143#if (LWIP_ARP && (ARP_TABLE_SIZE > 0x7f))
144 #error "ARP_TABLE_SIZE must fit in an s8_t, you have to reduce it in your lwipopts.h"
145#endif
146
147
148#if ARP_QUEUEING
149/**
150 * Free a complete queue of etharp entries
151 *
152 * @param q a qeueue of etharp_q_entry's to free
153 */
154static void
155free_etharp_q(struct etharp_q_entry *q)
156{
157 struct etharp_q_entry *r;
158 LWIP_ASSERT("q != NULL", q != NULL);
159 LWIP_ASSERT("q->p != NULL", q->p != NULL);
160 while (q) {
161 r = q;
162 q = q->next;
163 LWIP_ASSERT("r->p != NULL", (r->p != NULL));
164 pbuf_free(r->p);
165 memp_free(MEMP_ARP_QUEUE, r);
166 }
167}
168#else /* ARP_QUEUEING */
169
170/** Compatibility define: free the queued pbuf */
171#define free_etharp_q(q) pbuf_free(q)
172
173#endif /* ARP_QUEUEING */
174
175/** Clean up ARP table entries */
176static void
177etharp_free_entry(int i)
178{
179 /* remove from SNMP ARP index tree */
180 snmp_delete_arpidx_tree(arp_table[i].netif, &arp_table[i].ipaddr);
181 /* and empty packet queue */
182 if (arp_table[i].q != NULL) {
183 /* remove all queued packets */
184 LWIP_DEBUGF(ETHARP_DEBUG, ("etharp_free_entry: freeing entry %"U16_F", packet queue %p.\n", (u16_t)i, (void *)(arp_table[i].q)));
185 free_etharp_q(arp_table[i].q);
186 arp_table[i].q = NULL;
187 }
188 /* recycle entry for re-use */
189 arp_table[i].state = ETHARP_STATE_EMPTY;
190#ifdef LWIP_DEBUG
191 /* for debugging, clean out the complete entry */
192 arp_table[i].ctime = 0;
193 arp_table[i].netif = NULL;
194 ip_addr_set_zero(&arp_table[i].ipaddr);
195 arp_table[i].ethaddr = ethzero;
196#endif /* LWIP_DEBUG */
197}
198
199/**
200 * Clears expired entries in the ARP table.
201 *
202 * This function should be called every ETHARP_TMR_INTERVAL milliseconds (5 seconds),
203 * in order to expire entries in the ARP table.
204 */
205void
206etharp_tmr(void)
207{
208 u8_t i;
209
210 LWIP_DEBUGF(ETHARP_DEBUG, ("etharp_timer\n"));
211 /* remove expired entries from the ARP table */
212 for (i = 0; i < ARP_TABLE_SIZE; ++i) {
213 u8_t state = arp_table[i].state;
214 if (state != ETHARP_STATE_EMPTY
215#if ETHARP_SUPPORT_STATIC_ENTRIES
216 && (state != ETHARP_STATE_STATIC)
217#endif /* ETHARP_SUPPORT_STATIC_ENTRIES */
218 ) {
219 arp_table[i].ctime++;
220 if ((arp_table[i].ctime >= ARP_MAXAGE) ||
221 ((arp_table[i].state == ETHARP_STATE_PENDING) &&
222 (arp_table[i].ctime >= ARP_MAXPENDING))) {
223 /* pending or stable entry has become old! */
224 LWIP_DEBUGF(ETHARP_DEBUG, ("etharp_timer: expired %s entry %"U16_F".\n",
225 arp_table[i].state >= ETHARP_STATE_STABLE ? "stable" : "pending", (u16_t)i));
226 /* clean up entries that have just been expired */
227 etharp_free_entry(i);
228 }
229 else if (arp_table[i].state == ETHARP_STATE_STABLE_REREQUESTING) {
230 /* Reset state to stable, so that the next transmitted packet will
231 re-send an ARP request. */
232 arp_table[i].state = ETHARP_STATE_STABLE;
233 }
234#if ARP_QUEUEING
235 /* still pending entry? (not expired) */
236 if (arp_table[i].state == ETHARP_STATE_PENDING) {
237 /* resend an ARP query here? */
238 }
239#endif /* ARP_QUEUEING */
240 }
241 }
242}
243
244/**
245 * Search the ARP table for a matching or new entry.
246 *
247 * If an IP address is given, return a pending or stable ARP entry that matches
248 * the address. If no match is found, create a new entry with this address set,
249 * but in state ETHARP_EMPTY. The caller must check and possibly change the
250 * state of the returned entry.
251 *
252 * If ipaddr is NULL, return a initialized new entry in state ETHARP_EMPTY.
253 *
254 * In all cases, attempt to create new entries from an empty entry. If no
255 * empty entries are available and ETHARP_FLAG_TRY_HARD flag is set, recycle
256 * old entries. Heuristic choose the least important entry for recycling.
257 *
258 * @param ipaddr IP address to find in ARP cache, or to add if not found.
259 * @param flags @see definition of ETHARP_FLAG_*
260 * @param netif netif related to this address (used for NETIF_HWADDRHINT)
261 *
262 * @return The ARP entry index that matched or is created, ERR_MEM if no
263 * entry is found or could be recycled.
264 */
265static s8_t
266etharp_find_entry(ip_addr_t *ipaddr, u8_t flags)
267{
268 s8_t old_pending = ARP_TABLE_SIZE, old_stable = ARP_TABLE_SIZE;
269 s8_t empty = ARP_TABLE_SIZE;
270 u8_t i = 0, age_pending = 0, age_stable = 0;
271 /* oldest entry with packets on queue */
272 s8_t old_queue = ARP_TABLE_SIZE;
273 /* its age */
274 u8_t age_queue = 0;
275
276 /**
277 * a) do a search through the cache, remember candidates
278 * b) select candidate entry
279 * c) create new entry
280 */
281
282 /* a) in a single search sweep, do all of this
283 * 1) remember the first empty entry (if any)
284 * 2) remember the oldest stable entry (if any)
285 * 3) remember the oldest pending entry without queued packets (if any)
286 * 4) remember the oldest pending entry with queued packets (if any)
287 * 5) search for a matching IP entry, either pending or stable
288 * until 5 matches, or all entries are searched for.
289 */
290
291 for (i = 0; i < ARP_TABLE_SIZE; ++i) {
292 u8_t state = arp_table[i].state;
293 /* no empty entry found yet and now we do find one? */
294 if ((empty == ARP_TABLE_SIZE) && (state == ETHARP_STATE_EMPTY)) {
295 LWIP_DEBUGF(ETHARP_DEBUG, ("etharp_find_entry: found empty entry %"U16_F"\n", (u16_t)i));
296 /* remember first empty entry */
297 empty = i;
298 } else if (state != ETHARP_STATE_EMPTY) {
299 LWIP_ASSERT("state == ETHARP_STATE_PENDING || state >= ETHARP_STATE_STABLE",
300 state == ETHARP_STATE_PENDING || state >= ETHARP_STATE_STABLE);
301 /* if given, does IP address match IP address in ARP entry? */
302 if (ipaddr && ip_addr_cmp(ipaddr, &arp_table[i].ipaddr)) {
303 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_find_entry: found matching entry %"U16_F"\n", (u16_t)i));
304 /* found exact IP address match, simply bail out */
305 return i;
306 }
307 /* pending entry? */
308 if (state == ETHARP_STATE_PENDING) {
309 /* pending with queued packets? */
310 if (arp_table[i].q != NULL) {
311 if (arp_table[i].ctime >= age_queue) {
312 old_queue = i;
313 age_queue = arp_table[i].ctime;
314 }
315 } else
316 /* pending without queued packets? */
317 {
318 if (arp_table[i].ctime >= age_pending) {
319 old_pending = i;
320 age_pending = arp_table[i].ctime;
321 }
322 }
323 /* stable entry? */
324 } else if (state >= ETHARP_STATE_STABLE) {
325#if ETHARP_SUPPORT_STATIC_ENTRIES
326 /* don't record old_stable for static entries since they never expire */
327 if (state < ETHARP_STATE_STATIC)
328#endif /* ETHARP_SUPPORT_STATIC_ENTRIES */
329 {
330 /* remember entry with oldest stable entry in oldest, its age in maxtime */
331 if (arp_table[i].ctime >= age_stable) {
332 old_stable = i;
333 age_stable = arp_table[i].ctime;
334 }
335 }
336 }
337 }
338 }
339 /* { we have no match } => try to create a new entry */
340
341 /* don't create new entry, only search? */
342 if (((flags & ETHARP_FLAG_FIND_ONLY) != 0) ||
343 /* or no empty entry found and not allowed to recycle? */
344 ((empty == ARP_TABLE_SIZE) && ((flags & ETHARP_FLAG_TRY_HARD) == 0))) {
345 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_find_entry: no empty entry found and not allowed to recycle\n"));
346 return (s8_t)ERR_MEM;
347 }
348
349 /* b) choose the least destructive entry to recycle:
350 * 1) empty entry
351 * 2) oldest stable entry
352 * 3) oldest pending entry without queued packets
353 * 4) oldest pending entry with queued packets
354 *
355 * { ETHARP_FLAG_TRY_HARD is set at this point }
356 */
357
358 /* 1) empty entry available? */
359 if (empty < ARP_TABLE_SIZE) {
360 i = empty;
361 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_find_entry: selecting empty entry %"U16_F"\n", (u16_t)i));
362 } else {
363 /* 2) found recyclable stable entry? */
364 if (old_stable < ARP_TABLE_SIZE) {
365 /* recycle oldest stable*/
366 i = old_stable;
367 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_find_entry: selecting oldest stable entry %"U16_F"\n", (u16_t)i));
368 /* no queued packets should exist on stable entries */
369 LWIP_ASSERT("arp_table[i].q == NULL", arp_table[i].q == NULL);
370 /* 3) found recyclable pending entry without queued packets? */
371 } else if (old_pending < ARP_TABLE_SIZE) {
372 /* recycle oldest pending */
373 i = old_pending;
374 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_find_entry: selecting oldest pending entry %"U16_F" (without queue)\n", (u16_t)i));
375 /* 4) found recyclable pending entry with queued packets? */
376 } else if (old_queue < ARP_TABLE_SIZE) {
377 /* recycle oldest pending (queued packets are free in etharp_free_entry) */
378 i = old_queue;
379 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_find_entry: selecting oldest pending entry %"U16_F", freeing packet queue %p\n", (u16_t)i, (void *)(arp_table[i].q)));
380 /* no empty or recyclable entries found */
381 } else {
382 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_find_entry: no empty or recyclable entries found\n"));
383 return (s8_t)ERR_MEM;
384 }
385
386 /* { empty or recyclable entry found } */
387 LWIP_ASSERT("i < ARP_TABLE_SIZE", i < ARP_TABLE_SIZE);
388 etharp_free_entry(i);
389 }
390
391 LWIP_ASSERT("i < ARP_TABLE_SIZE", i < ARP_TABLE_SIZE);
392 LWIP_ASSERT("arp_table[i].state == ETHARP_STATE_EMPTY",
393 arp_table[i].state == ETHARP_STATE_EMPTY);
394
395 /* IP address given? */
396 if (ipaddr != NULL) {
397 /* set IP address */
398 ip_addr_copy(arp_table[i].ipaddr, *ipaddr);
399 }
400 arp_table[i].ctime = 0;
401 return (err_t)i;
402}
403
404/**
405 * Send an IP packet on the network using netif->linkoutput
406 * The ethernet header is filled in before sending.
407 *
408 * @params netif the lwIP network interface on which to send the packet
409 * @params p the packet to send, p->payload pointing to the (uninitialized) ethernet header
410 * @params src the source MAC address to be copied into the ethernet header
411 * @params dst the destination MAC address to be copied into the ethernet header
412 * @return ERR_OK if the packet was sent, any other err_t on failure
413 */
414static err_t
415etharp_send_ip(struct netif *netif, struct pbuf *p, struct eth_addr *src, struct eth_addr *dst)
416{
417 struct eth_hdr *ethhdr = (struct eth_hdr *)p->payload;
418
419 LWIP_ASSERT("netif->hwaddr_len must be the same as ETHARP_HWADDR_LEN for etharp!",
420 (netif->hwaddr_len == ETHARP_HWADDR_LEN));
421 ETHADDR32_COPY(&ethhdr->dest, dst);
422 ETHADDR16_COPY(&ethhdr->src, src);
423 ethhdr->type = PP_HTONS(ETHTYPE_IP);
424 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_send_ip: sending packet %p\n", (void *)p));
425 /* send the packet */
426 return netif->linkoutput(netif, p);
427}
428
429/**
430 * Update (or insert) a IP/MAC address pair in the ARP cache.
431 *
432 * If a pending entry is resolved, any queued packets will be sent
433 * at this point.
434 *
435 * @param netif netif related to this entry (used for NETIF_ADDRHINT)
436 * @param ipaddr IP address of the inserted ARP entry.
437 * @param ethaddr Ethernet address of the inserted ARP entry.
438 * @param flags @see definition of ETHARP_FLAG_*
439 *
440 * @return
441 * - ERR_OK Succesfully updated ARP cache.
442 * - ERR_MEM If we could not add a new ARP entry when ETHARP_FLAG_TRY_HARD was set.
443 * - ERR_ARG Non-unicast address given, those will not appear in ARP cache.
444 *
445 * @see pbuf_free()
446 */
447static err_t
448etharp_update_arp_entry(struct netif *netif, ip_addr_t *ipaddr, struct eth_addr *ethaddr, u8_t flags)
449{
450 s8_t i;
451 LWIP_ASSERT("netif->hwaddr_len == ETHARP_HWADDR_LEN", netif->hwaddr_len == ETHARP_HWADDR_LEN);
452 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",
453 ip4_addr1_16(ipaddr), ip4_addr2_16(ipaddr), ip4_addr3_16(ipaddr), ip4_addr4_16(ipaddr),
454 ethaddr->addr[0], ethaddr->addr[1], ethaddr->addr[2],
455 ethaddr->addr[3], ethaddr->addr[4], ethaddr->addr[5]));
456 /* non-unicast address? */
457 if (ip_addr_isany(ipaddr) ||
458 ip_addr_isbroadcast(ipaddr, netif) ||
459 ip_addr_ismulticast(ipaddr)) {
460 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_update_arp_entry: will not add non-unicast IP address to ARP cache\n"));
461 return ERR_ARG;
462 }
463 /* find or create ARP entry */
464 i = etharp_find_entry(ipaddr, flags);
465 /* bail out if no entry could be found */
466 if (i < 0) {
467 return (err_t)i;
468 }
469
470#if ETHARP_SUPPORT_STATIC_ENTRIES
471 if (flags & ETHARP_FLAG_STATIC_ENTRY) {
472 /* record static type */
473 arp_table[i].state = ETHARP_STATE_STATIC;
474 } else
475#endif /* ETHARP_SUPPORT_STATIC_ENTRIES */
476 {
477 /* mark it stable */
478 arp_table[i].state = ETHARP_STATE_STABLE;
479 }
480
481 /* record network interface */
482 arp_table[i].netif = netif;
483 /* insert in SNMP ARP index tree */
484 snmp_insert_arpidx_tree(netif, &arp_table[i].ipaddr);
485
486 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_update_arp_entry: updating stable entry %"S16_F"\n", (s16_t)i));
487 /* update address */
488 ETHADDR32_COPY(&arp_table[i].ethaddr, ethaddr);
489 /* reset time stamp */
490 arp_table[i].ctime = 0;
491 /* this is where we will send out queued packets! */
492#if ARP_QUEUEING
493 while (arp_table[i].q != NULL) {
494 struct pbuf *p;
495 /* remember remainder of queue */
496 struct etharp_q_entry *q = arp_table[i].q;
497 /* pop first item off the queue */
498 arp_table[i].q = q->next;
499 /* get the packet pointer */
500 p = q->p;
501 /* now queue entry can be freed */
502 memp_free(MEMP_ARP_QUEUE, q);
503#else /* ARP_QUEUEING */
504 if (arp_table[i].q != NULL) {
505 struct pbuf *p = arp_table[i].q;
506 arp_table[i].q = NULL;
507#endif /* ARP_QUEUEING */
508 /* send the queued IP packet */
509 etharp_send_ip(netif, p, (struct eth_addr*)(netif->hwaddr), ethaddr);
510 /* free the queued IP packet */
511 pbuf_free(p);
512 }
513 return ERR_OK;
514}
515
516#if ETHARP_SUPPORT_STATIC_ENTRIES
517/** Add a new static entry to the ARP table. If an entry exists for the
518 * specified IP address, this entry is overwritten.
519 * If packets are queued for the specified IP address, they are sent out.
520 *
521 * @param ipaddr IP address for the new static entry
522 * @param ethaddr ethernet address for the new static entry
523 * @return @see return values of etharp_add_static_entry
524 */
525err_t
526etharp_add_static_entry(ip_addr_t *ipaddr, struct eth_addr *ethaddr)
527{
528 struct netif *netif;
529 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",
530 ip4_addr1_16(ipaddr), ip4_addr2_16(ipaddr), ip4_addr3_16(ipaddr), ip4_addr4_16(ipaddr),
531 ethaddr->addr[0], ethaddr->addr[1], ethaddr->addr[2],
532 ethaddr->addr[3], ethaddr->addr[4], ethaddr->addr[5]));
533
534 netif = ip_route(ipaddr);
535 if (netif == NULL) {
536 return ERR_RTE;
537 }
538
539 return etharp_update_arp_entry(netif, ipaddr, ethaddr, ETHARP_FLAG_TRY_HARD | ETHARP_FLAG_STATIC_ENTRY);
540}
541
542/** Remove a static entry from the ARP table previously added with a call to
543 * etharp_add_static_entry.
544 *
545 * @param ipaddr IP address of the static entry to remove
546 * @return ERR_OK: entry removed
547 * ERR_MEM: entry wasn't found
548 * ERR_ARG: entry wasn't a static entry but a dynamic one
549 */
550err_t
551etharp_remove_static_entry(ip_addr_t *ipaddr)
552{
553 s8_t i;
554 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_remove_static_entry: %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
555 ip4_addr1_16(ipaddr), ip4_addr2_16(ipaddr), ip4_addr3_16(ipaddr), ip4_addr4_16(ipaddr)));
556
557 /* find or create ARP entry */
558 i = etharp_find_entry(ipaddr, ETHARP_FLAG_FIND_ONLY);
559 /* bail out if no entry could be found */
560 if (i < 0) {
561 return (err_t)i;
562 }
563
564 if (arp_table[i].state != ETHARP_STATE_STATIC) {
565 /* entry wasn't a static entry, cannot remove it */
566 return ERR_ARG;
567 }
568 /* entry found, free it */
569 etharp_free_entry(i);
570 return ERR_OK;
571}
572#endif /* ETHARP_SUPPORT_STATIC_ENTRIES */
573
574/**
575 * Remove all ARP table entries of the specified netif.
576 *
577 * @param netif points to a network interface
578 */
579void etharp_cleanup_netif(struct netif *netif)
580{
581 u8_t i;
582
583 for (i = 0; i < ARP_TABLE_SIZE; ++i) {
584 u8_t state = arp_table[i].state;
585 if ((state != ETHARP_STATE_EMPTY) && (arp_table[i].netif == netif)) {
586 etharp_free_entry(i);
587 }
588 }
589}
590
591/**
592 * Finds (stable) ethernet/IP address pair from ARP table
593 * using interface and IP address index.
594 * @note the addresses in the ARP table are in network order!
595 *
596 * @param netif points to interface index
597 * @param ipaddr points to the (network order) IP address index
598 * @param eth_ret points to return pointer
599 * @param ip_ret points to return pointer
600 * @return table index if found, -1 otherwise
601 */
602s8_t
603etharp_find_addr(struct netif *netif, ip_addr_t *ipaddr,
604 struct eth_addr **eth_ret, ip_addr_t **ip_ret)
605{
606 s8_t i;
607
608 LWIP_ASSERT("eth_ret != NULL && ip_ret != NULL",
609 eth_ret != NULL && ip_ret != NULL);
610
611 LWIP_UNUSED_ARG(netif);
612
613 i = etharp_find_entry(ipaddr, ETHARP_FLAG_FIND_ONLY);
614 if((i >= 0) && (arp_table[i].state >= ETHARP_STATE_STABLE)) {
615 *eth_ret = &arp_table[i].ethaddr;
616 *ip_ret = &arp_table[i].ipaddr;
617 return i;
618 }
619 return -1;
620}
621
622#if ETHARP_TRUST_IP_MAC
623/**
624 * Updates the ARP table using the given IP packet.
625 *
626 * Uses the incoming IP packet's source address to update the
627 * ARP cache for the local network. The function does not alter
628 * or free the packet. This function must be called before the
629 * packet p is passed to the IP layer.
630 *
631 * @param netif The lwIP network interface on which the IP packet pbuf arrived.
632 * @param p The IP packet that arrived on netif.
633 *
634 * @return NULL
635 *
636 * @see pbuf_free()
637 */
638static void
639etharp_ip_input(struct netif *netif, struct pbuf *p)
640{
641 struct eth_hdr *ethhdr;
642 struct ip_hdr *iphdr;
643 ip_addr_t iphdr_src;
644 LWIP_ERROR("netif != NULL", (netif != NULL), return;);
645
646 /* Only insert an entry if the source IP address of the
647 incoming IP packet comes from a host on the local network. */
648 ethhdr = (struct eth_hdr *)p->payload;
649 iphdr = (struct ip_hdr *)((u8_t*)ethhdr + SIZEOF_ETH_HDR);
650#if ETHARP_SUPPORT_VLAN
651 if (ethhdr->type == PP_HTONS(ETHTYPE_VLAN)) {
652 iphdr = (struct ip_hdr *)((u8_t*)ethhdr + SIZEOF_ETH_HDR + SIZEOF_VLAN_HDR);
653 }
654#endif /* ETHARP_SUPPORT_VLAN */
655
656 ip_addr_copy(iphdr_src, iphdr->src);
657
658 /* source is not on the local network? */
659 if (!ip_addr_netcmp(&iphdr_src, &(netif->ip_addr), &(netif->netmask))) {
660 /* do nothing */
661 return;
662 }
663
664 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_ip_input: updating ETHARP table.\n"));
665 /* update the source IP address in the cache, if present */
666 /* @todo We could use ETHARP_FLAG_TRY_HARD if we think we are going to talk
667 * back soon (for example, if the destination IP address is ours. */
668 etharp_update_arp_entry(netif, &iphdr_src, &(ethhdr->src), ETHARP_FLAG_FIND_ONLY);
669}
670#endif /* ETHARP_TRUST_IP_MAC */
671
672/**
673 * Responds to ARP requests to us. Upon ARP replies to us, add entry to cache
674 * send out queued IP packets. Updates cache with snooped address pairs.
675 *
676 * Should be called for incoming ARP packets. The pbuf in the argument
677 * is freed by this function.
678 *
679 * @param netif The lwIP network interface on which the ARP packet pbuf arrived.
680 * @param ethaddr Ethernet address of netif.
681 * @param p The ARP packet that arrived on netif. Is freed by this function.
682 *
683 * @return NULL
684 *
685 * @see pbuf_free()
686 */
687static void
688etharp_arp_input(struct netif *netif, struct eth_addr *ethaddr, struct pbuf *p)
689{
690 struct etharp_hdr *hdr;
691 struct eth_hdr *ethhdr;
692 /* these are aligned properly, whereas the ARP header fields might not be */
693 ip_addr_t sipaddr, dipaddr;
694 u8_t for_us;
695#if LWIP_AUTOIP
696 const u8_t * ethdst_hwaddr;
697#endif /* LWIP_AUTOIP */
698
699 LWIP_ERROR("netif != NULL", (netif != NULL), return;);
700
701 /* drop short ARP packets: we have to check for p->len instead of p->tot_len here
702 since a struct etharp_hdr is pointed to p->payload, so it musn't be chained! */
703 if (p->len < SIZEOF_ETHARP_PACKET) {
704 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING,
705 ("etharp_arp_input: packet dropped, too short (%"S16_F"/%"S16_F")\n", p->tot_len,
706 (s16_t)SIZEOF_ETHARP_PACKET));
707 ETHARP_STATS_INC(etharp.lenerr);
708 ETHARP_STATS_INC(etharp.drop);
709 pbuf_free(p);
710 return;
711 }
712
713 ethhdr = (struct eth_hdr *)p->payload;
714 hdr = (struct etharp_hdr *)((u8_t*)ethhdr + SIZEOF_ETH_HDR);
715#if ETHARP_SUPPORT_VLAN
716 if (ethhdr->type == PP_HTONS(ETHTYPE_VLAN)) {
717 hdr = (struct etharp_hdr *)(((u8_t*)ethhdr) + SIZEOF_ETH_HDR + SIZEOF_VLAN_HDR);
718 }
719#endif /* ETHARP_SUPPORT_VLAN */
720
721 /* RFC 826 "Packet Reception": */
722 if ((hdr->hwtype != PP_HTONS(HWTYPE_ETHERNET)) ||
723 (hdr->hwlen != ETHARP_HWADDR_LEN) ||
724 (hdr->protolen != sizeof(ip_addr_t)) ||
725 (hdr->proto != PP_HTONS(ETHTYPE_IP))) {
726 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_WARNING,
727 ("etharp_arp_input: packet dropped, wrong hw type, hwlen, proto, protolen or ethernet type (%"U16_F"/%"U16_F"/%"U16_F"/%"U16_F")\n",
728 hdr->hwtype, hdr->hwlen, hdr->proto, hdr->protolen));
729 ETHARP_STATS_INC(etharp.proterr);
730 ETHARP_STATS_INC(etharp.drop);
731 pbuf_free(p);
732 return;
733 }
734 ETHARP_STATS_INC(etharp.recv);
735
736#if LWIP_AUTOIP
737 /* We have to check if a host already has configured our random
738 * created link local address and continously check if there is
739 * a host with this IP-address so we can detect collisions */
740 autoip_arp_reply(netif, hdr);
741#endif /* LWIP_AUTOIP */
742
743 /* Copy struct ip_addr2 to aligned ip_addr, to support compilers without
744 * structure packing (not using structure copy which breaks strict-aliasing rules). */
745 IPADDR2_COPY(&sipaddr, &hdr->sipaddr);
746 IPADDR2_COPY(&dipaddr, &hdr->dipaddr);
747
748 /* this interface is not configured? */
749 if (ip_addr_isany(&netif->ip_addr)) {
750 for_us = 0;
751 } else {
752 /* ARP packet directed to us? */
753 for_us = (u8_t)ip_addr_cmp(&dipaddr, &(netif->ip_addr));
754 }
755
756 /* ARP message directed to us?
757 -> add IP address in ARP cache; assume requester wants to talk to us,
758 can result in directly sending the queued packets for this host.
759 ARP message not directed to us?
760 -> update the source IP address in the cache, if present */
761 etharp_update_arp_entry(netif, &sipaddr, &(hdr->shwaddr),
762 for_us ? ETHARP_FLAG_TRY_HARD : ETHARP_FLAG_FIND_ONLY);
763
764 /* now act on the message itself */
765 switch (hdr->opcode) {
766 /* ARP request? */
767 case PP_HTONS(ARP_REQUEST):
768 /* ARP request. If it asked for our address, we send out a
769 * reply. In any case, we time-stamp any existing ARP entry,
770 * and possiby send out an IP packet that was queued on it. */
771
772 LWIP_DEBUGF (ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_arp_input: incoming ARP request\n"));
773 /* ARP request for our address? */
774 if (for_us) {
775
776 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_arp_input: replying to ARP request for our IP address\n"));
777 /* Re-use pbuf to send ARP reply.
778 Since we are re-using an existing pbuf, we can't call etharp_raw since
779 that would allocate a new pbuf. */
780 hdr->opcode = htons(ARP_REPLY);
781
782 IPADDR2_COPY(&hdr->dipaddr, &hdr->sipaddr);
783 IPADDR2_COPY(&hdr->sipaddr, &netif->ip_addr);
784
785 LWIP_ASSERT("netif->hwaddr_len must be the same as ETHARP_HWADDR_LEN for etharp!",
786 (netif->hwaddr_len == ETHARP_HWADDR_LEN));
787#if LWIP_AUTOIP
788 /* If we are using Link-Local, all ARP packets that contain a Link-Local
789 * 'sender IP address' MUST be sent using link-layer broadcast instead of
790 * link-layer unicast. (See RFC3927 Section 2.5, last paragraph) */
791 ethdst_hwaddr = ip_addr_islinklocal(&netif->ip_addr) ? (u8_t*)(ethbroadcast.addr) : hdr->shwaddr.addr;
792#endif /* LWIP_AUTOIP */
793
794 ETHADDR16_COPY(&hdr->dhwaddr, &hdr->shwaddr);
795#if LWIP_AUTOIP
796 ETHADDR16_COPY(&ethhdr->dest, ethdst_hwaddr);
797#else /* LWIP_AUTOIP */
798 ETHADDR16_COPY(&ethhdr->dest, &hdr->shwaddr);
799#endif /* LWIP_AUTOIP */
800 ETHADDR16_COPY(&hdr->shwaddr, ethaddr);
801 ETHADDR16_COPY(&ethhdr->src, ethaddr);
802
803 /* hwtype, hwaddr_len, proto, protolen and the type in the ethernet header
804 are already correct, we tested that before */
805
806 /* return ARP reply */
807 netif->linkoutput(netif, p);
808 /* we are not configured? */
809 } else if (ip_addr_isany(&netif->ip_addr)) {
810 /* { for_us == 0 and netif->ip_addr.addr == 0 } */
811 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_arp_input: we are unconfigured, ARP request ignored.\n"));
812 /* request was not directed to us */
813 } else {
814 /* { for_us == 0 and netif->ip_addr.addr != 0 } */
815 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_arp_input: ARP request was not for us.\n"));
816 }
817 break;
818 case PP_HTONS(ARP_REPLY):
819 /* ARP reply. We already updated the ARP cache earlier. */
820 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_arp_input: incoming ARP reply\n"));
821#if (LWIP_DHCP && DHCP_DOES_ARP_CHECK)
822 /* DHCP wants to know about ARP replies from any host with an
823 * IP address also offered to us by the DHCP server. We do not
824 * want to take a duplicate IP address on a single network.
825 * @todo How should we handle redundant (fail-over) interfaces? */
826 dhcp_arp_reply(netif, &sipaddr);
827#endif /* (LWIP_DHCP && DHCP_DOES_ARP_CHECK) */
828 break;
829 default:
830 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_arp_input: ARP unknown opcode type %"S16_F"\n", htons(hdr->opcode)));
831 ETHARP_STATS_INC(etharp.err);
832 break;
833 }
834 /* free ARP packet */
835 pbuf_free(p);
836}
837
838/** Just a small helper function that sends a pbuf to an ethernet address
839 * in the arp_table specified by the index 'arp_idx'.
840 */
841static err_t
842etharp_output_to_arp_index(struct netif *netif, struct pbuf *q, u8_t arp_idx)
843{
844 LWIP_ASSERT("arp_table[arp_idx].state >= ETHARP_STATE_STABLE",
845 arp_table[arp_idx].state >= ETHARP_STATE_STABLE);
846 /* if arp table entry is about to expire: re-request it,
847 but only if its state is ETHARP_STATE_STABLE to prevent flooding the
848 network with ARP requests if this address is used frequently. */
849 if ((arp_table[arp_idx].state == ETHARP_STATE_STABLE) &&
850 (arp_table[arp_idx].ctime >= ARP_AGE_REREQUEST_USED)) {
851 if (etharp_request(netif, &arp_table[arp_idx].ipaddr) == ERR_OK) {
852 arp_table[arp_idx].state = ETHARP_STATE_STABLE_REREQUESTING;
853 }
854 }
855
856 return etharp_send_ip(netif, q, (struct eth_addr*)(netif->hwaddr),
857 &arp_table[arp_idx].ethaddr);
858}
859
860/**
861 * Resolve and fill-in Ethernet address header for outgoing IP packet.
862 *
863 * For IP multicast and broadcast, corresponding Ethernet addresses
864 * are selected and the packet is transmitted on the link.
865 *
866 * For unicast addresses, the packet is submitted to etharp_query(). In
867 * case the IP address is outside the local network, the IP address of
868 * the gateway is used.
869 *
870 * @param netif The lwIP network interface which the IP packet will be sent on.
871 * @param q The pbuf(s) containing the IP packet to be sent.
872 * @param ipaddr The IP address of the packet destination.
873 *
874 * @return
875 * - ERR_RTE No route to destination (no gateway to external networks),
876 * or the return type of either etharp_query() or etharp_send_ip().
877 */
878err_t
879etharp_output(struct netif *netif, struct pbuf *q, ip_addr_t *ipaddr)
880{
881 struct eth_addr *dest;
882 struct eth_addr mcastaddr;
883 ip_addr_t *dst_addr = ipaddr;
884
885 LWIP_ASSERT("netif != NULL", netif != NULL);
886 LWIP_ASSERT("q != NULL", q != NULL);
887 LWIP_ASSERT("ipaddr != NULL", ipaddr != NULL);
888
889 /* make room for Ethernet header - should not fail */
890 if (pbuf_header(q, sizeof(struct eth_hdr)) != 0) {
891 /* bail out */
892 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS,
893 ("etharp_output: could not allocate room for header.\n"));
894 LINK_STATS_INC(link.lenerr);
895 return ERR_BUF;
896 }
897
898 /* Determine on destination hardware address. Broadcasts and multicasts
899 * are special, other IP addresses are looked up in the ARP table. */
900
901 /* broadcast destination IP address? */
902 if (ip_addr_isbroadcast(ipaddr, netif)) {
903 /* broadcast on Ethernet also */
904 dest = (struct eth_addr *)&ethbroadcast;
905 /* multicast destination IP address? */
906 } else if (ip_addr_ismulticast(ipaddr)) {
907 /* Hash IP multicast address to MAC address.*/
908 mcastaddr.addr[0] = LL_MULTICAST_ADDR_0;
909 mcastaddr.addr[1] = LL_MULTICAST_ADDR_1;
910 mcastaddr.addr[2] = LL_MULTICAST_ADDR_2;
911 mcastaddr.addr[3] = ip4_addr2(ipaddr) & 0x7f;
912 mcastaddr.addr[4] = ip4_addr3(ipaddr);
913 mcastaddr.addr[5] = ip4_addr4(ipaddr);
914 /* destination Ethernet address is multicast */
915 dest = &mcastaddr;
916 /* unicast destination IP address? */
917 } else {
918 s8_t i;
919 /* outside local network? if so, this can neither be a global broadcast nor
920 a subnet broadcast. */
921 if (!ip_addr_netcmp(ipaddr, &(netif->ip_addr), &(netif->netmask)) &&
922 !ip_addr_islinklocal(ipaddr)) {
923#if LWIP_AUTOIP
924 struct ip_hdr *iphdr = (struct ip_hdr*)((u8_t*)q->payload +
925 sizeof(struct eth_hdr));
926 /* According to RFC 3297, chapter 2.6.2 (Forwarding Rules), a packet with
927 a link-local source address must always be "directly to its destination
928 on the same physical link. The host MUST NOT send the packet to any
929 router for forwarding". */
930 if (!ip_addr_islinklocal(&iphdr->src))
931#endif /* LWIP_AUTOIP */
932 {
933 /* interface has default gateway? */
934 if (!ip_addr_isany(&netif->gw)) {
935 /* send to hardware address of default gateway IP address */
936 dst_addr = &(netif->gw);
937 /* no default gateway available */
938 } else {
939 /* no route to destination error (default gateway missing) */
940 return ERR_RTE;
941 }
942 }
943 }
944#if LWIP_NETIF_HWADDRHINT
945 if (netif->addr_hint != NULL) {
946 /* per-pcb cached entry was given */
947 u8_t etharp_cached_entry = *(netif->addr_hint);
948 if (etharp_cached_entry < ARP_TABLE_SIZE) {
949#endif /* LWIP_NETIF_HWADDRHINT */
950 if ((arp_table[etharp_cached_entry].state >= ETHARP_STATE_STABLE) &&
951 (ip_addr_cmp(dst_addr, &arp_table[etharp_cached_entry].ipaddr))) {
952 /* the per-pcb-cached entry is stable and the right one! */
953 ETHARP_STATS_INC(etharp.cachehit);
954 return etharp_output_to_arp_index(netif, q, etharp_cached_entry);
955 }
956#if LWIP_NETIF_HWADDRHINT
957 }
958 }
959#endif /* LWIP_NETIF_HWADDRHINT */
960
961 /* find stable entry: do this here since this is a critical path for
962 throughput and etharp_find_entry() is kind of slow */
963 for (i = 0; i < ARP_TABLE_SIZE; i++) {
964 if ((arp_table[i].state >= ETHARP_STATE_STABLE) &&
965 (ip_addr_cmp(dst_addr, &arp_table[i].ipaddr))) {
966 /* found an existing, stable entry */
967 ETHARP_SET_HINT(netif, i);
968 return etharp_output_to_arp_index(netif, q, i);
969 }
970 }
971 /* no stable entry found, use the (slower) query function:
972 queue on destination Ethernet address belonging to ipaddr */
973 return etharp_query(netif, dst_addr, q);
974 }
975
976 /* continuation for multicast/broadcast destinations */
977 /* obtain source Ethernet address of the given interface */
978 /* send packet directly on the link */
979 return etharp_send_ip(netif, q, (struct eth_addr*)(netif->hwaddr), dest);
980}
981
982/**
983 * Send an ARP request for the given IP address and/or queue a packet.
984 *
985 * If the IP address was not yet in the cache, a pending ARP cache entry
986 * is added and an ARP request is sent for the given address. The packet
987 * is queued on this entry.
988 *
989 * If the IP address was already pending in the cache, a new ARP request
990 * is sent for the given address. The packet is queued on this entry.
991 *
992 * If the IP address was already stable in the cache, and a packet is
993 * given, it is directly sent and no ARP request is sent out.
994 *
995 * If the IP address was already stable in the cache, and no packet is
996 * given, an ARP request is sent out.
997 *
998 * @param netif The lwIP network interface on which ipaddr
999 * must be queried for.
1000 * @param ipaddr The IP address to be resolved.
1001 * @param q If non-NULL, a pbuf that must be delivered to the IP address.
1002 * q is not freed by this function.
1003 *
1004 * @note q must only be ONE packet, not a packet queue!
1005 *
1006 * @return
1007 * - ERR_BUF Could not make room for Ethernet header.
1008 * - ERR_MEM Hardware address unknown, and no more ARP entries available
1009 * to query for address or queue the packet.
1010 * - ERR_MEM Could not queue packet due to memory shortage.
1011 * - ERR_RTE No route to destination (no gateway to external networks).
1012 * - ERR_ARG Non-unicast address given, those will not appear in ARP cache.
1013 *
1014 */
1015err_t
1016etharp_query(struct netif *netif, ip_addr_t *ipaddr, struct pbuf *q)
1017{
1018 struct eth_addr * srcaddr = (struct eth_addr *)netif->hwaddr;
1019 err_t result = ERR_MEM;
1020 s8_t i; /* ARP entry index */
1021
1022 /* non-unicast address? */
1023 if (ip_addr_isbroadcast(ipaddr, netif) ||
1024 ip_addr_ismulticast(ipaddr) ||
1025 ip_addr_isany(ipaddr)) {
1026 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: will not add non-unicast IP address to ARP cache\n"));
1027 return ERR_ARG;
1028 }
1029
1030 /* find entry in ARP cache, ask to create entry if queueing packet */
1031 i = etharp_find_entry(ipaddr, ETHARP_FLAG_TRY_HARD);
1032
1033 /* could not find or create entry? */
1034 if (i < 0) {
1035 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: could not create ARP entry\n"));
1036 if (q) {
1037 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: packet dropped\n"));
1038 ETHARP_STATS_INC(etharp.memerr);
1039 }
1040 return (err_t)i;
1041 }
1042
1043 /* mark a fresh entry as pending (we just sent a request) */
1044 if (arp_table[i].state == ETHARP_STATE_EMPTY) {
1045 arp_table[i].state = ETHARP_STATE_PENDING;
1046 }
1047
1048 /* { i is either a STABLE or (new or existing) PENDING entry } */
1049 LWIP_ASSERT("arp_table[i].state == PENDING or STABLE",
1050 ((arp_table[i].state == ETHARP_STATE_PENDING) ||
1051 (arp_table[i].state >= ETHARP_STATE_STABLE)));
1052
1053 /* do we have a pending entry? or an implicit query request? */
1054 if ((arp_table[i].state == ETHARP_STATE_PENDING) || (q == NULL)) {
1055 /* try to resolve it; send out ARP request */
1056 result = etharp_request(netif, ipaddr);
1057 if (result != ERR_OK) {
1058 /* ARP request couldn't be sent */
1059 /* We don't re-send arp request in etharp_tmr, but we still queue packets,
1060 since this failure could be temporary, and the next packet calling
1061 etharp_query again could lead to sending the queued packets. */
1062 }
1063 if (q == NULL) {
1064 return result;
1065 }
1066 }
1067
1068 /* packet given? */
1069 LWIP_ASSERT("q != NULL", q != NULL);
1070 /* stable entry? */
1071 if (arp_table[i].state >= ETHARP_STATE_STABLE) {
1072 /* we have a valid IP->Ethernet address mapping */
1073 ETHARP_SET_HINT(netif, i);
1074 /* send the packet */
1075 result = etharp_send_ip(netif, q, srcaddr, &(arp_table[i].ethaddr));
1076 /* pending entry? (either just created or already pending */
1077 } else if (arp_table[i].state == ETHARP_STATE_PENDING) {
1078 /* entry is still pending, queue the given packet 'q' */
1079 struct pbuf *p;
1080 int copy_needed = 0;
1081 /* IF q includes a PBUF_REF, PBUF_POOL or PBUF_RAM, we have no choice but
1082 * to copy the whole queue into a new PBUF_RAM (see bug #11400)
1083 * PBUF_ROMs can be left as they are, since ROM must not get changed. */
1084 p = q;
1085 while (p) {
1086 LWIP_ASSERT("no packet queues allowed!", (p->len != p->tot_len) || (p->next == 0));
1087 if(p->type != PBUF_ROM) {
1088 copy_needed = 1;
1089 break;
1090 }
1091 p = p->next;
1092 }
1093 if(copy_needed) {
1094 /* copy the whole packet into new pbufs */
1095 p = pbuf_alloc(PBUF_RAW, p->tot_len, PBUF_RAM);
1096 if(p != NULL) {
1097 if (pbuf_copy(p, q) != ERR_OK) {
1098 pbuf_free(p);
1099 p = NULL;
1100 }
1101 }
1102 } else {
1103 /* referencing the old pbuf is enough */
1104 p = q;
1105 pbuf_ref(p);
1106 }
1107 /* packet could be taken over? */
1108 if (p != NULL) {
1109 /* queue packet ... */
1110#if ARP_QUEUEING
1111 struct etharp_q_entry *new_entry;
1112 /* allocate a new arp queue entry */
1113 new_entry = (struct etharp_q_entry *)memp_malloc(MEMP_ARP_QUEUE);
1114 if (new_entry != NULL) {
1115 new_entry->next = 0;
1116 new_entry->p = p;
1117 if(arp_table[i].q != NULL) {
1118 /* queue was already existent, append the new entry to the end */
1119 struct etharp_q_entry *r;
1120 r = arp_table[i].q;
1121 while (r->next != NULL) {
1122 r = r->next;
1123 }
1124 r->next = new_entry;
1125 } else {
1126 /* queue did not exist, first item in queue */
1127 arp_table[i].q = new_entry;
1128 }
1129 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: queued packet %p on ARP entry %"S16_F"\n", (void *)q, (s16_t)i));
1130 result = ERR_OK;
1131 } else {
1132 /* the pool MEMP_ARP_QUEUE is empty */
1133 pbuf_free(p);
1134 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));
1135 result = ERR_MEM;
1136 }
1137#else /* ARP_QUEUEING */
1138 /* always queue one packet per ARP request only, freeing a previously queued packet */
1139 if (arp_table[i].q != NULL) {
1140 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: dropped previously queued packet %p for ARP entry %"S16_F"\n", (void *)q, (s16_t)i));
1141 pbuf_free(arp_table[i].q);
1142 }
1143 arp_table[i].q = p;
1144 result = ERR_OK;
1145 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: queued packet %p on ARP entry %"S16_F"\n", (void *)q, (s16_t)i));
1146#endif /* ARP_QUEUEING */
1147 } else {
1148 ETHARP_STATS_INC(etharp.memerr);
1149 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));
1150 result = ERR_MEM;
1151 }
1152 }
1153 return result;
1154}
1155
1156/**
1157 * Send a raw ARP packet (opcode and all addresses can be modified)
1158 *
1159 * @param netif the lwip network interface on which to send the ARP packet
1160 * @param ethsrc_addr the source MAC address for the ethernet header
1161 * @param ethdst_addr the destination MAC address for the ethernet header
1162 * @param hwsrc_addr the source MAC address for the ARP protocol header
1163 * @param ipsrc_addr the source IP address for the ARP protocol header
1164 * @param hwdst_addr the destination MAC address for the ARP protocol header
1165 * @param ipdst_addr the destination IP address for the ARP protocol header
1166 * @param opcode the type of the ARP packet
1167 * @return ERR_OK if the ARP packet has been sent
1168 * ERR_MEM if the ARP packet couldn't be allocated
1169 * any other err_t on failure
1170 */
1171#if !LWIP_AUTOIP
1172static
1173#endif /* LWIP_AUTOIP */
1174err_t
1175etharp_raw(struct netif *netif, const struct eth_addr *ethsrc_addr,
1176 const struct eth_addr *ethdst_addr,
1177 const struct eth_addr *hwsrc_addr, const ip_addr_t *ipsrc_addr,
1178 const struct eth_addr *hwdst_addr, const ip_addr_t *ipdst_addr,
1179 const u16_t opcode)
1180{
1181 struct pbuf *p;
1182 err_t result = ERR_OK;
1183 struct eth_hdr *ethhdr;
1184 struct etharp_hdr *hdr;
1185#if LWIP_AUTOIP
1186 const u8_t * ethdst_hwaddr;
1187#endif /* LWIP_AUTOIP */
1188
1189 LWIP_ASSERT("netif != NULL", netif != NULL);
1190
1191 /* allocate a pbuf for the outgoing ARP request packet */
1192 p = pbuf_alloc(PBUF_RAW, SIZEOF_ETHARP_PACKET, PBUF_RAM);
1193 /* could allocate a pbuf for an ARP request? */
1194 if (p == NULL) {
1195 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_LEVEL_SERIOUS,
1196 ("etharp_raw: could not allocate pbuf for ARP request.\n"));
1197 ETHARP_STATS_INC(etharp.memerr);
1198 return ERR_MEM;
1199 }
1200 LWIP_ASSERT("check that first pbuf can hold struct etharp_hdr",
1201 (p->len >= SIZEOF_ETHARP_PACKET));
1202
1203 ethhdr = (struct eth_hdr *)p->payload;
1204 hdr = (struct etharp_hdr *)((u8_t*)ethhdr + SIZEOF_ETH_HDR);
1205 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_raw: sending raw ARP packet.\n"));
1206 hdr->opcode = htons(opcode);
1207
1208 LWIP_ASSERT("netif->hwaddr_len must be the same as ETHARP_HWADDR_LEN for etharp!",
1209 (netif->hwaddr_len == ETHARP_HWADDR_LEN));
1210#if LWIP_AUTOIP
1211 /* If we are using Link-Local, all ARP packets that contain a Link-Local
1212 * 'sender IP address' MUST be sent using link-layer broadcast instead of
1213 * link-layer unicast. (See RFC3927 Section 2.5, last paragraph) */
1214 ethdst_hwaddr = ip_addr_islinklocal(ipsrc_addr) ? (u8_t*)(ethbroadcast.addr) : ethdst_addr->addr;
1215#endif /* LWIP_AUTOIP */
1216 /* Write the ARP MAC-Addresses */
1217 ETHADDR16_COPY(&hdr->shwaddr, hwsrc_addr);
1218 ETHADDR16_COPY(&hdr->dhwaddr, hwdst_addr);
1219 /* Write the Ethernet MAC-Addresses */
1220#if LWIP_AUTOIP
1221 ETHADDR16_COPY(&ethhdr->dest, ethdst_hwaddr);
1222#else /* LWIP_AUTOIP */
1223 ETHADDR16_COPY(&ethhdr->dest, ethdst_addr);
1224#endif /* LWIP_AUTOIP */
1225 ETHADDR16_COPY(&ethhdr->src, ethsrc_addr);
1226 /* Copy struct ip_addr2 to aligned ip_addr, to support compilers without
1227 * structure packing. */
1228 IPADDR2_COPY(&hdr->sipaddr, ipsrc_addr);
1229 IPADDR2_COPY(&hdr->dipaddr, ipdst_addr);
1230
1231 hdr->hwtype = PP_HTONS(HWTYPE_ETHERNET);
1232 hdr->proto = PP_HTONS(ETHTYPE_IP);
1233 /* set hwlen and protolen */
1234 hdr->hwlen = ETHARP_HWADDR_LEN;
1235 hdr->protolen = sizeof(ip_addr_t);
1236
1237 ethhdr->type = PP_HTONS(ETHTYPE_ARP);
1238 /* send ARP query */
1239 result = netif->linkoutput(netif, p);
1240 ETHARP_STATS_INC(etharp.xmit);
1241 /* free ARP query packet */
1242 pbuf_free(p);
1243 p = NULL;
1244 /* could not allocate pbuf for ARP request */
1245
1246 return result;
1247}
1248
1249/**
1250 * Send an ARP request packet asking for ipaddr.
1251 *
1252 * @param netif the lwip network interface on which to send the request
1253 * @param ipaddr the IP address for which to ask
1254 * @return ERR_OK if the request has been sent
1255 * ERR_MEM if the ARP packet couldn't be allocated
1256 * any other err_t on failure
1257 */
1258err_t
1259etharp_request(struct netif *netif, ip_addr_t *ipaddr)
1260{
1261 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_request: sending ARP request.\n"));
1262 return etharp_raw(netif, (struct eth_addr *)netif->hwaddr, &ethbroadcast,
1263 (struct eth_addr *)netif->hwaddr, &netif->ip_addr, &ethzero,
1264 ipaddr, ARP_REQUEST);
1265}
1266#endif /* LWIP_ARP */
1267
1268/**
1269 * Process received ethernet frames. Using this function instead of directly
1270 * calling ip_input and passing ARP frames through etharp in ethernetif_input,
1271 * the ARP cache is protected from concurrent access.
1272 *
1273 * @param p the recevied packet, p->payload pointing to the ethernet header
1274 * @param netif the network interface on which the packet was received
1275 */
1276err_t
1277ethernet_input(struct pbuf *p, struct netif *netif)
1278{
1279 struct eth_hdr* ethhdr;
1280 u16_t type;
1281#if LWIP_ARP || ETHARP_SUPPORT_VLAN
1282 s16_t ip_hdr_offset = SIZEOF_ETH_HDR;
1283#endif /* LWIP_ARP || ETHARP_SUPPORT_VLAN */
1284
1285 if (p->len <= SIZEOF_ETH_HDR) {
1286 /* a packet with only an ethernet header (or less) is not valid for us */
1287 ETHARP_STATS_INC(etharp.proterr);
1288 ETHARP_STATS_INC(etharp.drop);
1289 goto free_and_return;
1290 }
1291
1292 /* points to packet payload, which starts with an Ethernet header */
1293 ethhdr = (struct eth_hdr *)p->payload;
1294 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE,
1295 ("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",
1296 (unsigned)ethhdr->dest.addr[0], (unsigned)ethhdr->dest.addr[1], (unsigned)ethhdr->dest.addr[2],
1297 (unsigned)ethhdr->dest.addr[3], (unsigned)ethhdr->dest.addr[4], (unsigned)ethhdr->dest.addr[5],
1298 (unsigned)ethhdr->src.addr[0], (unsigned)ethhdr->src.addr[1], (unsigned)ethhdr->src.addr[2],
1299 (unsigned)ethhdr->src.addr[3], (unsigned)ethhdr->src.addr[4], (unsigned)ethhdr->src.addr[5],
1300 (unsigned)htons(ethhdr->type)));
1301
1302 type = ethhdr->type;
1303#if ETHARP_SUPPORT_VLAN
1304 if (type == PP_HTONS(ETHTYPE_VLAN)) {
1305 struct eth_vlan_hdr *vlan = (struct eth_vlan_hdr*)(((char*)ethhdr) + SIZEOF_ETH_HDR);
1306 if (p->len <= SIZEOF_ETH_HDR + SIZEOF_VLAN_HDR) {
1307 /* a packet with only an ethernet/vlan header (or less) is not valid for us */
1308 ETHARP_STATS_INC(etharp.proterr);
1309 ETHARP_STATS_INC(etharp.drop);
1310 goto free_and_return;
1311 }
1312#if defined(ETHARP_VLAN_CHECK) || defined(ETHARP_VLAN_CHECK_FN) /* if not, allow all VLANs */
1313#ifdef ETHARP_VLAN_CHECK_FN
1314 if (!ETHARP_VLAN_CHECK_FN(ethhdr, vlan)) {
1315#elif defined(ETHARP_VLAN_CHECK)
1316 if (VLAN_ID(vlan) != ETHARP_VLAN_CHECK) {
1317#endif
1318 /* silently ignore this packet: not for our VLAN */
1319 pbuf_free(p);
1320 return ERR_OK;
1321 }
1322#endif /* defined(ETHARP_VLAN_CHECK) || defined(ETHARP_VLAN_CHECK_FN) */
1323 type = vlan->tpid;
1324 ip_hdr_offset = SIZEOF_ETH_HDR + SIZEOF_VLAN_HDR;
1325 }
1326#endif /* ETHARP_SUPPORT_VLAN */
1327
1328#if LWIP_ARP_FILTER_NETIF
1329 netif = LWIP_ARP_FILTER_NETIF_FN(p, netif, htons(type));
1330#endif /* LWIP_ARP_FILTER_NETIF*/
1331
1332 if (ethhdr->dest.addr[0] & 1) {
1333 /* this might be a multicast or broadcast packet */
1334 if (ethhdr->dest.addr[0] == LL_MULTICAST_ADDR_0) {
1335 if ((ethhdr->dest.addr[1] == LL_MULTICAST_ADDR_1) &&
1336 (ethhdr->dest.addr[2] == LL_MULTICAST_ADDR_2)) {
1337 /* mark the pbuf as link-layer multicast */
1338 p->flags |= PBUF_FLAG_LLMCAST;
1339 }
1340 } else if (eth_addr_cmp(&ethhdr->dest, &ethbroadcast)) {
1341 /* mark the pbuf as link-layer broadcast */
1342 p->flags |= PBUF_FLAG_LLBCAST;
1343 }
1344 }
1345
1346 switch (type) {
1347#if LWIP_ARP
1348 /* IP packet? */
1349 case PP_HTONS(ETHTYPE_IP):
1350 if (!(netif->flags & NETIF_FLAG_ETHARP)) {
1351 goto free_and_return;
1352 }
1353#if ETHARP_TRUST_IP_MAC
1354 /* update ARP table */
1355 etharp_ip_input(netif, p);
1356#endif /* ETHARP_TRUST_IP_MAC */
1357 /* skip Ethernet header */
1358 if(pbuf_header(p, -ip_hdr_offset)) {
1359 LWIP_ASSERT("Can't move over header in packet", 0);
1360 goto free_and_return;
1361 } else {
1362 /* pass to IP layer */
1363 ip_input(p, netif);
1364 }
1365 break;
1366
1367 case PP_HTONS(ETHTYPE_ARP):
1368 if (!(netif->flags & NETIF_FLAG_ETHARP)) {
1369 goto free_and_return;
1370 }
1371 /* pass p to ARP module */
1372 etharp_arp_input(netif, (struct eth_addr*)(netif->hwaddr), p);
1373 break;
1374#endif /* LWIP_ARP */
1375#if PPPOE_SUPPORT
1376 case PP_HTONS(ETHTYPE_PPPOEDISC): /* PPP Over Ethernet Discovery Stage */
1377 pppoe_disc_input(netif, p);
1378 break;
1379
1380 case PP_HTONS(ETHTYPE_PPPOE): /* PPP Over Ethernet Session Stage */
1381 pppoe_data_input(netif, p);
1382 break;
1383#endif /* PPPOE_SUPPORT */
1384
1385 default:
1386 ETHARP_STATS_INC(etharp.proterr);
1387 ETHARP_STATS_INC(etharp.drop);
1388 goto free_and_return;
1389 }
1390
1391 /* This means the pbuf is freed or consumed,
1392 so the caller doesn't have to free it again */
1393 return ERR_OK;
1394
1395free_and_return:
1396 pbuf_free(p);
1397 return ERR_OK;
1398}
1399#endif /* LWIP_ARP || LWIP_ETHERNET */
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