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