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etharp.c
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00001 /** 00002 * @file 00003 * Address Resolution Protocol module for IP over Ethernet 00004 * 00005 * Functionally, ARP is divided into two parts. The first maps an IP address 00006 * to a physical address when sending a packet, and the second part answers 00007 * requests from other machines for our physical address. 00008 * 00009 * This implementation complies with RFC 826 (Ethernet ARP). It supports 00010 * Gratuitious ARP from RFC3220 (IP Mobility Support for IPv4) section 4.6 00011 * if an interface calls etharp_query(our_netif, its_ip_addr, NULL) upon 00012 * address change. 00013 */ 00014 00015 /* 00016 * Copyright (c) 2001-2003 Swedish Institute of Computer Science. 00017 * Copyright (c) 2003-2004 Leon Woestenberg <leon.woestenberg@axon.tv> 00018 * Copyright (c) 2003-2004 Axon Digital Design B.V., The Netherlands. 00019 * All rights reserved. 00020 * 00021 * Redistribution and use in source and binary forms, with or without modification, 00022 * are permitted provided that the following conditions are met: 00023 * 00024 * 1. Redistributions of source code must retain the above copyright notice, 00025 * this list of conditions and the following disclaimer. 00026 * 2. Redistributions in binary form must reproduce the above copyright notice, 00027 * this list of conditions and the following disclaimer in the documentation 00028 * and/or other materials provided with the distribution. 00029 * 3. The name of the author may not be used to endorse or promote products 00030 * derived from this software without specific prior written permission. 00031 * 00032 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 00033 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 00034 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 00035 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 00036 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 00037 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 00038 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 00039 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 00040 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 00041 * OF SUCH DAMAGE. 00042 * 00043 * This file is part of the lwIP TCP/IP stack. 00044 * 00045 */ 00046 00047 #include "lwip/opt.h" 00048 00049 #if LWIP_ARP /* don't build if not configured for use in lwipopts.h */ 00050 00051 #include "lwip/inet.h" 00052 #include "lwip/ip.h" 00053 #include "lwip/stats.h" 00054 #include "lwip/snmp.h" 00055 #include "lwip/dhcp.h" 00056 #include "lwip/autoip.h" 00057 #include "netif/etharp.h" 00058 00059 #if PPPOE_SUPPORT 00060 #include "netif/ppp_oe.h" 00061 #endif /* PPPOE_SUPPORT */ 00062 00063 #include <string.h> 00064 00065 /** the time an ARP entry stays valid after its last update, 00066 * for ARP_TMR_INTERVAL = 5000, this is 00067 * (240 * 5) seconds = 20 minutes. 00068 */ 00069 #define ARP_MAXAGE 240 00070 /** the time an ARP entry stays pending after first request, 00071 * for ARP_TMR_INTERVAL = 5000, this is 00072 * (2 * 5) seconds = 10 seconds. 00073 * 00074 * @internal Keep this number at least 2, otherwise it might 00075 * run out instantly if the timeout occurs directly after a request. 00076 */ 00077 #define ARP_MAXPENDING 2 00078 00079 #define HWTYPE_ETHERNET 1 00080 00081 #define ARPH_HWLEN(hdr) (ntohs((hdr)->_hwlen_protolen) >> 8) 00082 #define ARPH_PROTOLEN(hdr) (ntohs((hdr)->_hwlen_protolen) & 0xff) 00083 00084 #define ARPH_HWLEN_SET(hdr, len) (hdr)->_hwlen_protolen = htons(ARPH_PROTOLEN(hdr) | ((len) << 8)) 00085 #define ARPH_PROTOLEN_SET(hdr, len) (hdr)->_hwlen_protolen = htons((len) | (ARPH_HWLEN(hdr) << 8)) 00086 00087 enum etharp_state { 00088 ETHARP_STATE_EMPTY = 0, 00089 ETHARP_STATE_PENDING, 00090 ETHARP_STATE_STABLE 00091 }; 00092 00093 struct etharp_entry { 00094 #if ARP_QUEUEING 00095 /** 00096 * Pointer to queue of pending outgoing packets on this ARP entry. 00097 */ 00098 struct etharp_q_entry *q; 00099 #endif 00100 struct ip_addr ipaddr; 00101 struct eth_addr ethaddr; 00102 enum etharp_state state; 00103 u8_t ctime; 00104 struct netif *netif; 00105 }; 00106 00107 const struct eth_addr ethbroadcast = {{0xff,0xff,0xff,0xff,0xff,0xff}}; 00108 const struct eth_addr ethzero = {{0,0,0,0,0,0}}; 00109 static struct etharp_entry arp_table[ARP_TABLE_SIZE]; 00110 #if !LWIP_NETIF_HWADDRHINT 00111 static u8_t etharp_cached_entry; 00112 #endif 00113 00114 /** 00115 * Try hard to create a new entry - we want the IP address to appear in 00116 * the cache (even if this means removing an active entry or so). */ 00117 #define ETHARP_TRY_HARD 1 00118 #define ETHARP_FIND_ONLY 2 00119 00120 #if LWIP_NETIF_HWADDRHINT 00121 #define NETIF_SET_HINT(netif, hint) if (((netif) != NULL) && ((netif)->addr_hint != NULL)) \ 00122 *((netif)->addr_hint) = (hint); 00123 static s8_t find_entry(struct ip_addr *ipaddr, u8_t flags, struct netif *netif); 00124 #else /* LWIP_NETIF_HWADDRHINT */ 00125 static s8_t find_entry(struct ip_addr *ipaddr, u8_t flags); 00126 #endif /* LWIP_NETIF_HWADDRHINT */ 00127 00128 static err_t update_arp_entry(struct netif *netif, struct ip_addr *ipaddr, struct eth_addr *ethaddr, u8_t flags); 00129 00130 00131 /* Some checks, instead of etharp_init(): */ 00132 #if (LWIP_ARP && (ARP_TABLE_SIZE > 0x7f)) 00133 #error "If you want to use ARP, ARP_TABLE_SIZE must fit in an s8_t, so, you have to reduce it in your lwipopts.h" 00134 #endif 00135 00136 00137 #if ARP_QUEUEING 00138 /** 00139 * Free a complete queue of etharp entries 00140 * 00141 * @param q a qeueue of etharp_q_entry's to free 00142 */ 00143 static void 00144 free_etharp_q(struct etharp_q_entry *q) 00145 { 00146 struct etharp_q_entry *r; 00147 LWIP_ASSERT("q != NULL", q != NULL); 00148 LWIP_ASSERT("q->p != NULL", q->p != NULL); 00149 while (q) { 00150 r = q; 00151 q = q->next; 00152 LWIP_ASSERT("r->p != NULL", (r->p != NULL)); 00153 pbuf_free(r->p); 00154 memp_free(MEMP_ARP_QUEUE, r); 00155 } 00156 } 00157 #endif 00158 00159 /** 00160 * Clears expired entries in the ARP table. 00161 * 00162 * This function should be called every ETHARP_TMR_INTERVAL microseconds (5 seconds), 00163 * in order to expire entries in the ARP table. 00164 */ 00165 void 00166 etharp_tmr(void) 00167 { 00168 u8_t i; 00169 00170 LWIP_DEBUGF(ETHARP_DEBUG, ("etharp_timer\n")); 00171 /* remove expired entries from the ARP table */ 00172 for (i = 0; i < ARP_TABLE_SIZE; ++i) { 00173 arp_table[i].ctime++; 00174 if (((arp_table[i].state == ETHARP_STATE_STABLE) && 00175 (arp_table[i].ctime >= ARP_MAXAGE)) || 00176 ((arp_table[i].state == ETHARP_STATE_PENDING) && 00177 (arp_table[i].ctime >= ARP_MAXPENDING))) { 00178 /* pending or stable entry has become old! */ 00179 LWIP_DEBUGF(ETHARP_DEBUG, ("etharp_timer: expired %s entry %"U16_F".\n", 00180 arp_table[i].state == ETHARP_STATE_STABLE ? "stable" : "pending", (u16_t)i)); 00181 /* clean up entries that have just been expired */ 00182 /* remove from SNMP ARP index tree */ 00183 snmp_delete_arpidx_tree(arp_table[i].netif, &arp_table[i].ipaddr); 00184 #if ARP_QUEUEING 00185 /* and empty packet queue */ 00186 if (arp_table[i].q != NULL) { 00187 /* remove all queued packets */ 00188 LWIP_DEBUGF(ETHARP_DEBUG, ("etharp_timer: freeing entry %"U16_F", packet queue %p.\n", (u16_t)i, (void *)(arp_table[i].q))); 00189 free_etharp_q(arp_table[i].q); 00190 arp_table[i].q = NULL; 00191 } 00192 #endif 00193 /* recycle entry for re-use */ 00194 arp_table[i].state = ETHARP_STATE_EMPTY; 00195 } 00196 #if ARP_QUEUEING 00197 /* still pending entry? (not expired) */ 00198 if (arp_table[i].state == ETHARP_STATE_PENDING) { 00199 /* resend an ARP query here? */ 00200 } 00201 #endif 00202 } 00203 } 00204 00205 /** 00206 * Search the ARP table for a matching or new entry. 00207 * 00208 * If an IP address is given, return a pending or stable ARP entry that matches 00209 * the address. If no match is found, create a new entry with this address set, 00210 * but in state ETHARP_EMPTY. The caller must check and possibly change the 00211 * state of the returned entry. 00212 * 00213 * If ipaddr is NULL, return a initialized new entry in state ETHARP_EMPTY. 00214 * 00215 * In all cases, attempt to create new entries from an empty entry. If no 00216 * empty entries are available and ETHARP_TRY_HARD flag is set, recycle 00217 * old entries. Heuristic choose the least important entry for recycling. 00218 * 00219 * @param ipaddr IP address to find in ARP cache, or to add if not found. 00220 * @param flags 00221 * - ETHARP_TRY_HARD: Try hard to create a entry by allowing recycling of 00222 * active (stable or pending) entries. 00223 * 00224 * @return The ARP entry index that matched or is created, ERR_MEM if no 00225 * entry is found or could be recycled. 00226 */ 00227 static s8_t 00228 #if LWIP_NETIF_HWADDRHINT 00229 find_entry(struct ip_addr *ipaddr, u8_t flags, struct netif *netif) 00230 #else /* LWIP_NETIF_HWADDRHINT */ 00231 find_entry(struct ip_addr *ipaddr, u8_t flags) 00232 #endif /* LWIP_NETIF_HWADDRHINT */ 00233 { 00234 s8_t old_pending = ARP_TABLE_SIZE, old_stable = ARP_TABLE_SIZE; 00235 s8_t empty = ARP_TABLE_SIZE; 00236 u8_t i = 0, age_pending = 0, age_stable = 0; 00237 #if ARP_QUEUEING 00238 /* oldest entry with packets on queue */ 00239 s8_t old_queue = ARP_TABLE_SIZE; 00240 /* its age */ 00241 u8_t age_queue = 0; 00242 #endif 00243 00244 /* First, test if the last call to this function asked for the 00245 * same address. If so, we're really fast! */ 00246 if (ipaddr) { 00247 /* ipaddr to search for was given */ 00248 #if LWIP_NETIF_HWADDRHINT 00249 if ((netif != NULL) && (netif->addr_hint != NULL)) { 00250 /* per-pcb cached entry was given */ 00251 u8_t per_pcb_cache = *(netif->addr_hint); 00252 if ((per_pcb_cache < ARP_TABLE_SIZE) && arp_table[per_pcb_cache].state == ETHARP_STATE_STABLE) { 00253 /* the per-pcb-cached entry is stable */ 00254 if (ip_addr_cmp(ipaddr, &arp_table[per_pcb_cache].ipaddr)) { 00255 /* per-pcb cached entry was the right one! */ 00256 ETHARP_STATS_INC(etharp.cachehit); 00257 return per_pcb_cache; 00258 } 00259 } 00260 } 00261 #else /* #if LWIP_NETIF_HWADDRHINT */ 00262 if (arp_table[etharp_cached_entry].state == ETHARP_STATE_STABLE) { 00263 /* the cached entry is stable */ 00264 if (ip_addr_cmp(ipaddr, &arp_table[etharp_cached_entry].ipaddr)) { 00265 /* cached entry was the right one! */ 00266 ETHARP_STATS_INC(etharp.cachehit); 00267 return etharp_cached_entry; 00268 } 00269 } 00270 #endif /* #if LWIP_NETIF_HWADDRHINT */ 00271 } 00272 00273 /** 00274 * a) do a search through the cache, remember candidates 00275 * b) select candidate entry 00276 * c) create new entry 00277 */ 00278 00279 /* a) in a single search sweep, do all of this 00280 * 1) remember the first empty entry (if any) 00281 * 2) remember the oldest stable entry (if any) 00282 * 3) remember the oldest pending entry without queued packets (if any) 00283 * 4) remember the oldest pending entry with queued packets (if any) 00284 * 5) search for a matching IP entry, either pending or stable 00285 * until 5 matches, or all entries are searched for. 00286 */ 00287 00288 for (i = 0; i < ARP_TABLE_SIZE; ++i) { 00289 /* no empty entry found yet and now we do find one? */ 00290 if ((empty == ARP_TABLE_SIZE) && (arp_table[i].state == ETHARP_STATE_EMPTY)) { 00291 LWIP_DEBUGF(ETHARP_DEBUG, ("find_entry: found empty entry %"U16_F"\n", (u16_t)i)); 00292 /* remember first empty entry */ 00293 empty = i; 00294 } 00295 /* pending entry? */ 00296 else if (arp_table[i].state == ETHARP_STATE_PENDING) { 00297 /* if given, does IP address match IP address in ARP entry? */ 00298 if (ipaddr && ip_addr_cmp(ipaddr, &arp_table[i].ipaddr)) { 00299 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("find_entry: found matching pending entry %"U16_F"\n", (u16_t)i)); 00300 /* found exact IP address match, simply bail out */ 00301 #if LWIP_NETIF_HWADDRHINT 00302 NETIF_SET_HINT(netif, i); 00303 #else /* #if LWIP_NETIF_HWADDRHINT */ 00304 etharp_cached_entry = i; 00305 #endif /* #if LWIP_NETIF_HWADDRHINT */ 00306 return i; 00307 #if ARP_QUEUEING 00308 /* pending with queued packets? */ 00309 } else if (arp_table[i].q != NULL) { 00310 if (arp_table[i].ctime >= age_queue) { 00311 old_queue = i; 00312 age_queue = arp_table[i].ctime; 00313 } 00314 #endif 00315 /* pending without queued packets? */ 00316 } else { 00317 if (arp_table[i].ctime >= age_pending) { 00318 old_pending = i; 00319 age_pending = arp_table[i].ctime; 00320 } 00321 } 00322 } 00323 /* stable entry? */ 00324 else if (arp_table[i].state == ETHARP_STATE_STABLE) { 00325 /* if given, does IP address match IP address in ARP entry? */ 00326 if (ipaddr && ip_addr_cmp(ipaddr, &arp_table[i].ipaddr)) { 00327 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("find_entry: found matching stable entry %"U16_F"\n", (u16_t)i)); 00328 /* found exact IP address match, simply bail out */ 00329 #if LWIP_NETIF_HWADDRHINT 00330 NETIF_SET_HINT(netif, i); 00331 #else /* #if LWIP_NETIF_HWADDRHINT */ 00332 etharp_cached_entry = i; 00333 #endif /* #if LWIP_NETIF_HWADDRHINT */ 00334 return i; 00335 /* remember entry with oldest stable entry in oldest, its age in maxtime */ 00336 } else if (arp_table[i].ctime >= age_stable) { 00337 old_stable = i; 00338 age_stable = arp_table[i].ctime; 00339 } 00340 } 00341 } 00342 /* { we have no match } => try to create a new entry */ 00343 00344 /* no empty entry found and not allowed to recycle? */ 00345 if (((empty == ARP_TABLE_SIZE) && ((flags & ETHARP_TRY_HARD) == 0)) 00346 /* or don't create new entry, only search? */ 00347 || ((flags & ETHARP_FIND_ONLY) != 0)) { 00348 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("find_entry: no empty entry found and not allowed to recycle\n")); 00349 return (s8_t)ERR_MEM; 00350 } 00351 00352 /* b) choose the least destructive entry to recycle: 00353 * 1) empty entry 00354 * 2) oldest stable entry 00355 * 3) oldest pending entry without queued packets 00356 * 4) oldest pending entry without queued packets 00357 * 00358 * { ETHARP_TRY_HARD is set at this point } 00359 */ 00360 00361 /* 1) empty entry available? */ 00362 if (empty < ARP_TABLE_SIZE) { 00363 i = empty; 00364 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("find_entry: selecting empty entry %"U16_F"\n", (u16_t)i)); 00365 } 00366 /* 2) found recyclable stable entry? */ 00367 else if (old_stable < ARP_TABLE_SIZE) { 00368 /* recycle oldest stable*/ 00369 i = old_stable; 00370 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("find_entry: selecting oldest stable entry %"U16_F"\n", (u16_t)i)); 00371 #if ARP_QUEUEING 00372 /* no queued packets should exist on stable entries */ 00373 LWIP_ASSERT("arp_table[i].q == NULL", arp_table[i].q == NULL); 00374 #endif 00375 /* 3) found recyclable pending entry without queued packets? */ 00376 } else if (old_pending < ARP_TABLE_SIZE) { 00377 /* recycle oldest pending */ 00378 i = old_pending; 00379 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("find_entry: selecting oldest pending entry %"U16_F" (without queue)\n", (u16_t)i)); 00380 #if ARP_QUEUEING 00381 /* 4) found recyclable pending entry with queued packets? */ 00382 } else if (old_queue < ARP_TABLE_SIZE) { 00383 /* recycle oldest pending */ 00384 i = old_queue; 00385 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))); 00386 free_etharp_q(arp_table[i].q); 00387 arp_table[i].q = NULL; 00388 #endif 00389 /* no empty or recyclable entries found */ 00390 } else { 00391 return (s8_t)ERR_MEM; 00392 } 00393 00394 /* { empty or recyclable entry found } */ 00395 LWIP_ASSERT("i < ARP_TABLE_SIZE", i < ARP_TABLE_SIZE); 00396 00397 if (arp_table[i].state != ETHARP_STATE_EMPTY) 00398 { 00399 snmp_delete_arpidx_tree(arp_table[i].netif, &arp_table[i].ipaddr); 00400 } 00401 /* recycle entry (no-op for an already empty entry) */ 00402 arp_table[i].state = ETHARP_STATE_EMPTY; 00403 00404 /* IP address given? */ 00405 if (ipaddr != NULL) { 00406 /* set IP address */ 00407 ip_addr_set(&arp_table[i].ipaddr, ipaddr); 00408 } 00409 arp_table[i].ctime = 0; 00410 #if LWIP_NETIF_HWADDRHINT 00411 NETIF_SET_HINT(netif, i); 00412 #else /* #if LWIP_NETIF_HWADDRHINT */ 00413 etharp_cached_entry = i; 00414 #endif /* #if LWIP_NETIF_HWADDRHINT */ 00415 return (err_t)i; 00416 } 00417 00418 /** 00419 * Send an IP packet on the network using netif->linkoutput 00420 * The ethernet header is filled in before sending. 00421 * 00422 * @params netif the lwIP network interface on which to send the packet 00423 * @params p the packet to send, p->payload pointing to the (uninitialized) ethernet header 00424 * @params src the source MAC address to be copied into the ethernet header 00425 * @params dst the destination MAC address to be copied into the ethernet header 00426 * @return ERR_OK if the packet was sent, any other err_t on failure 00427 */ 00428 static err_t 00429 etharp_send_ip(struct netif *netif, struct pbuf *p, struct eth_addr *src, struct eth_addr *dst) 00430 { 00431 struct eth_hdr *ethhdr = static_cast<struct eth_hdr *>(p->payload); 00432 u8_t k; 00433 00434 LWIP_ASSERT("netif->hwaddr_len must be the same as ETHARP_HWADDR_LEN for etharp!", 00435 (netif->hwaddr_len == ETHARP_HWADDR_LEN)); 00436 k = ETHARP_HWADDR_LEN; 00437 while(k > 0) { 00438 k--; 00439 ethhdr->dest.addr[k] = dst->addr[k]; 00440 ethhdr->src.addr[k] = src->addr[k]; 00441 } 00442 ethhdr->type = htons(ETHTYPE_IP); 00443 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_send_ip: sending packet %p\n", (void *)p)); 00444 /* send the packet */ 00445 return netif->linkoutput(netif, p); 00446 } 00447 00448 /** 00449 * Update (or insert) a IP/MAC address pair in the ARP cache. 00450 * 00451 * If a pending entry is resolved, any queued packets will be sent 00452 * at this point. 00453 * 00454 * @param ipaddr IP address of the inserted ARP entry. 00455 * @param ethaddr Ethernet address of the inserted ARP entry. 00456 * @param flags Defines behaviour: 00457 * - ETHARP_TRY_HARD Allows ARP to insert this as a new item. If not specified, 00458 * only existing ARP entries will be updated. 00459 * 00460 * @return 00461 * - ERR_OK Succesfully updated ARP cache. 00462 * - ERR_MEM If we could not add a new ARP entry when ETHARP_TRY_HARD was set. 00463 * - ERR_ARG Non-unicast address given, those will not appear in ARP cache. 00464 * 00465 * @see pbuf_free() 00466 */ 00467 static err_t 00468 update_arp_entry(struct netif *netif, struct ip_addr *ipaddr, struct eth_addr *ethaddr, u8_t flags) 00469 { 00470 s8_t i; 00471 u8_t k; 00472 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE | 3, ("update_arp_entry()\n")); 00473 LWIP_ASSERT("netif->hwaddr_len == ETHARP_HWADDR_LEN", netif->hwaddr_len == ETHARP_HWADDR_LEN); 00474 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", 00475 ip4_addr1(ipaddr), ip4_addr2(ipaddr), ip4_addr3(ipaddr), ip4_addr4(ipaddr), 00476 ethaddr->addr[0], ethaddr->addr[1], ethaddr->addr[2], 00477 ethaddr->addr[3], ethaddr->addr[4], ethaddr->addr[5])); 00478 /* non-unicast address? */ 00479 if (ip_addr_isany(ipaddr) || 00480 ip_addr_isbroadcast(ipaddr, netif) || 00481 ip_addr_ismulticast(ipaddr)) { 00482 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("update_arp_entry: will not add non-unicast IP address to ARP cache\n")); 00483 return ERR_ARG; 00484 } 00485 /* find or create ARP entry */ 00486 #if LWIP_NETIF_HWADDRHINT 00487 i = find_entry(ipaddr, flags, netif); 00488 #else /* LWIP_NETIF_HWADDRHINT */ 00489 i = find_entry(ipaddr, flags); 00490 #endif /* LWIP_NETIF_HWADDRHINT */ 00491 /* bail out if no entry could be found */ 00492 if (i < 0) 00493 return (err_t)i; 00494 00495 /* mark it stable */ 00496 arp_table[i].state = ETHARP_STATE_STABLE; 00497 /* record network interface */ 00498 arp_table[i].netif = netif; 00499 00500 /* insert in SNMP ARP index tree */ 00501 snmp_insert_arpidx_tree(netif, &arp_table[i].ipaddr); 00502 00503 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("update_arp_entry: updating stable entry %"S16_F"\n", (s16_t)i)); 00504 /* update address */ 00505 k = ETHARP_HWADDR_LEN; 00506 while (k > 0) { 00507 k--; 00508 arp_table[i].ethaddr.addr[k] = ethaddr->addr[k]; 00509 } 00510 /* reset time stamp */ 00511 arp_table[i].ctime = 0; 00512 #if ARP_QUEUEING 00513 /* this is where we will send out queued packets! */ 00514 while (arp_table[i].q != NULL) { 00515 struct pbuf *p; 00516 /* remember remainder of queue */ 00517 struct etharp_q_entry *q = arp_table[i].q; 00518 /* pop first item off the queue */ 00519 arp_table[i].q = q->next; 00520 /* get the packet pointer */ 00521 p = q->p; 00522 /* now queue entry can be freed */ 00523 memp_free(MEMP_ARP_QUEUE, q); 00524 /* send the queued IP packet */ 00525 etharp_send_ip(netif, p, (struct eth_addr*)(netif->hwaddr), ethaddr); 00526 /* free the queued IP packet */ 00527 pbuf_free(p); 00528 } 00529 #endif 00530 return ERR_OK; 00531 } 00532 00533 /** 00534 * Finds (stable) ethernet/IP address pair from ARP table 00535 * using interface and IP address index. 00536 * @note the addresses in the ARP table are in network order! 00537 * 00538 * @param netif points to interface index 00539 * @param ipaddr points to the (network order) IP address index 00540 * @param eth_ret points to return pointer 00541 * @param ip_ret points to return pointer 00542 * @return table index if found, -1 otherwise 00543 */ 00544 s8_t 00545 etharp_find_addr(struct netif *netif, struct ip_addr *ipaddr, 00546 struct eth_addr **eth_ret, struct ip_addr **ip_ret) 00547 { 00548 s8_t i; 00549 00550 LWIP_UNUSED_ARG(netif); 00551 00552 #if LWIP_NETIF_HWADDRHINT 00553 i = find_entry(ipaddr, ETHARP_FIND_ONLY, NULL); 00554 #else /* LWIP_NETIF_HWADDRHINT */ 00555 i = find_entry(ipaddr, ETHARP_FIND_ONLY); 00556 #endif /* LWIP_NETIF_HWADDRHINT */ 00557 if((i >= 0) && arp_table[i].state == ETHARP_STATE_STABLE) { 00558 *eth_ret = &arp_table[i].ethaddr; 00559 *ip_ret = &arp_table[i].ipaddr; 00560 return i; 00561 } 00562 return -1; 00563 } 00564 00565 /** 00566 * Updates the ARP table using the given IP packet. 00567 * 00568 * Uses the incoming IP packet's source address to update the 00569 * ARP cache for the local network. The function does not alter 00570 * or free the packet. This function must be called before the 00571 * packet p is passed to the IP layer. 00572 * 00573 * @param netif The lwIP network interface on which the IP packet pbuf arrived. 00574 * @param p The IP packet that arrived on netif. 00575 * 00576 * @return NULL 00577 * 00578 * @see pbuf_free() 00579 */ 00580 void 00581 etharp_ip_input(struct netif *netif, struct pbuf *p) 00582 { 00583 struct ethip_hdr *hdr; 00584 LWIP_ERROR("netif != NULL", (netif != NULL), return;); 00585 /* Only insert an entry if the source IP address of the 00586 incoming IP packet comes from a host on the local network. */ 00587 hdr = static_cast<struct ethip_hdr *>(p->payload); 00588 /* source is not on the local network? */ 00589 if (!ip_addr_netcmp(&(hdr->ip.src), &(netif->ip_addr), &(netif->netmask))) { 00590 /* do nothing */ 00591 return; 00592 } 00593 00594 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_ip_input: updating ETHARP table.\n")); 00595 /* update ARP table */ 00596 /* @todo We could use ETHARP_TRY_HARD if we think we are going to talk 00597 * back soon (for example, if the destination IP address is ours. */ 00598 struct ip_addr hdripsrc; 00599 hdripsrc.addr = hdr->ip.src.addr; 00600 struct eth_addr hdrethsrc; 00601 CPY_ETH_ADDR(hdrethsrc, hdr->eth.src); 00602 update_arp_entry(netif, &(hdripsrc), &(hdrethsrc), 0); 00603 } 00604 00605 00606 /** 00607 * Responds to ARP requests to us. Upon ARP replies to us, add entry to cache 00608 * send out queued IP packets. Updates cache with snooped address pairs. 00609 * 00610 * Should be called for incoming ARP packets. The pbuf in the argument 00611 * is freed by this function. 00612 * 00613 * @param netif The lwIP network interface on which the ARP packet pbuf arrived. 00614 * @param ethaddr Ethernet address of netif. 00615 * @param p The ARP packet that arrived on netif. Is freed by this function. 00616 * 00617 * @return NULL 00618 * 00619 * @see pbuf_free() 00620 */ 00621 void 00622 etharp_arp_input(struct netif *netif, struct eth_addr *ethaddr, struct pbuf *p) 00623 { 00624 struct etharp_hdr *hdr; 00625 /* these are aligned properly, whereas the ARP header fields might not be */ 00626 struct ip_addr sipaddr, dipaddr; 00627 u8_t i; 00628 u8_t for_us; 00629 #if LWIP_AUTOIP 00630 const u8_t * ethdst_hwaddr; 00631 #endif /* LWIP_AUTOIP */ 00632 00633 LWIP_ERROR("netif != NULL", (netif != NULL), return;); 00634 00635 /* drop short ARP packets: we have to check for p->len instead of p->tot_len here 00636 since a struct etharp_hdr is pointed to p->payload, so it musn't be chained! */ 00637 if (p->len < sizeof(struct etharp_hdr)) { 00638 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE | 1, ("etharp_arp_input: packet dropped, too short (%"S16_F"/%"S16_F")\n", p->tot_len, (s16_t)sizeof(struct etharp_hdr))); 00639 ETHARP_STATS_INC(etharp.lenerr); 00640 ETHARP_STATS_INC(etharp.drop); 00641 pbuf_free(p); 00642 return; 00643 } 00644 00645 hdr = static_cast<struct etharp_hdr *>(p->payload); 00646 00647 /* RFC 826 "Packet Reception": */ 00648 if ((hdr->hwtype != htons(HWTYPE_ETHERNET)) || 00649 (hdr->_hwlen_protolen != htons((ETHARP_HWADDR_LEN << 8) | sizeof(struct ip_addr))) || 00650 (hdr->proto != htons(ETHTYPE_IP)) || 00651 (hdr->ethhdr.type != htons(ETHTYPE_ARP))) { 00652 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE | 1, 00653 ("etharp_arp_input: packet dropped, wrong hw type, hwlen, proto, protolen or ethernet type (%"U16_F"/%"U16_F"/%"U16_F"/%"U16_F"/%"U16_F")\n", 00654 hdr->hwtype, ARPH_HWLEN(hdr), hdr->proto, ARPH_PROTOLEN(hdr), hdr->ethhdr.type)); 00655 ETHARP_STATS_INC(etharp.proterr); 00656 ETHARP_STATS_INC(etharp.drop); 00657 pbuf_free(p); 00658 return; 00659 } 00660 ETHARP_STATS_INC(etharp.recv); 00661 00662 #if LWIP_AUTOIP 00663 /* We have to check if a host already has configured our random 00664 * created link local address and continously check if there is 00665 * a host with this IP-address so we can detect collisions */ 00666 autoip_arp_reply(netif, hdr); 00667 #endif /* LWIP_AUTOIP */ 00668 00669 /* Copy struct ip_addr2 to aligned ip_addr, to support compilers without 00670 * structure packing (not using structure copy which breaks strict-aliasing rules). */ 00671 SMEMCPY(&sipaddr, &hdr->sipaddr, sizeof(sipaddr)); 00672 SMEMCPY(&dipaddr, &hdr->dipaddr, sizeof(dipaddr)); 00673 00674 /* this interface is not configured? */ 00675 if (netif->ip_addr.addr == 0) { 00676 for_us = 0; 00677 } else { 00678 /* ARP packet directed to us? */ 00679 for_us = ip_addr_cmp(&dipaddr, &(netif->ip_addr)); 00680 } 00681 00682 /* ARP message directed to us? */ 00683 if (for_us) { 00684 /* add IP address in ARP cache; assume requester wants to talk to us. 00685 * can result in directly sending the queued packets for this host. */ 00686 struct eth_addr hdrshwaddr; 00687 CPY_ETH_ADDR(hdrshwaddr, hdr->shwaddr); 00688 update_arp_entry(netif, &sipaddr, &(hdrshwaddr), ETHARP_TRY_HARD); 00689 /* ARP message not directed to us? */ 00690 } else { 00691 /* update the source IP address in the cache, if present */ 00692 struct eth_addr hdrshwaddr; 00693 CPY_ETH_ADDR(hdrshwaddr, hdr->shwaddr); 00694 update_arp_entry(netif, &sipaddr, &(hdrshwaddr), 0); 00695 } 00696 00697 /* now act on the message itself */ 00698 switch (htons(hdr->opcode)) { 00699 /* ARP request? */ 00700 case ARP_REQUEST: 00701 /* ARP request. If it asked for our address, we send out a 00702 * reply. In any case, we time-stamp any existing ARP entry, 00703 * and possiby send out an IP packet that was queued on it. */ 00704 00705 LWIP_DEBUGF (ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_arp_input: incoming ARP request\n")); 00706 /* ARP request for our address? */ 00707 if (for_us) { 00708 00709 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_arp_input: replying to ARP request for our IP address\n")); 00710 /* Re-use pbuf to send ARP reply. 00711 Since we are re-using an existing pbuf, we can't call etharp_raw since 00712 that would allocate a new pbuf. */ 00713 hdr->opcode = htons(ARP_REPLY); 00714 00715 hdr->dipaddr = hdr->sipaddr; 00716 hdr->sipaddr = (*(struct ip_addr2 *)&netif->ip_addr); 00717 00718 LWIP_ASSERT("netif->hwaddr_len must be the same as ETHARP_HWADDR_LEN for etharp!", 00719 (netif->hwaddr_len == ETHARP_HWADDR_LEN)); 00720 i = ETHARP_HWADDR_LEN; 00721 #if LWIP_AUTOIP 00722 /* If we are using Link-Local, ARP packets must be broadcast on the 00723 * link layer. (See RFC3927 Section 2.5) */ 00724 ethdst_hwaddr = ((netif->autoip != NULL) && (netif->autoip->state != AUTOIP_STATE_OFF)) ? (u8_t*)(ethbroadcast.addr) : hdr->shwaddr.addr; 00725 #endif /* LWIP_AUTOIP */ 00726 00727 while(i > 0) { 00728 i--; 00729 hdr->dhwaddr.addr[i] = hdr->shwaddr.addr[i]; 00730 #if LWIP_AUTOIP 00731 hdr->ethhdr.dest.addr[i] = ethdst_hwaddr[i]; 00732 #else /* LWIP_AUTOIP */ 00733 hdr->ethhdr.dest.addr[i] = hdr->shwaddr.addr[i]; 00734 #endif /* LWIP_AUTOIP */ 00735 hdr->shwaddr.addr[i] = ethaddr->addr[i]; 00736 hdr->ethhdr.src.addr[i] = ethaddr->addr[i]; 00737 } 00738 00739 /* hwtype, hwaddr_len, proto, protolen and the type in the ethernet header 00740 are already correct, we tested that before */ 00741 00742 /* return ARP reply */ 00743 netif->linkoutput(netif, p); 00744 /* we are not configured? */ 00745 } else if (netif->ip_addr.addr == 0) { 00746 /* { for_us == 0 and netif->ip_addr.addr == 0 } */ 00747 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_arp_input: we are unconfigured, ARP request ignored.\n")); 00748 /* request was not directed to us */ 00749 } else { 00750 /* { for_us == 0 and netif->ip_addr.addr != 0 } */ 00751 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_arp_input: ARP request was not for us.\n")); 00752 } 00753 break; 00754 case ARP_REPLY: 00755 /* ARP reply. We already updated the ARP cache earlier. */ 00756 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_arp_input: incoming ARP reply\n")); 00757 #if (LWIP_DHCP && DHCP_DOES_ARP_CHECK) 00758 /* DHCP wants to know about ARP replies from any host with an 00759 * IP address also offered to us by the DHCP server. We do not 00760 * want to take a duplicate IP address on a single network. 00761 * @todo How should we handle redundant (fail-over) interfaces? */ 00762 dhcp_arp_reply(netif, &sipaddr); 00763 #endif 00764 break; 00765 default: 00766 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_arp_input: ARP unknown opcode type %"S16_F"\n", htons(hdr->opcode))); 00767 ETHARP_STATS_INC(etharp.err); 00768 break; 00769 } 00770 /* free ARP packet */ 00771 pbuf_free(p); 00772 } 00773 00774 /** 00775 * Resolve and fill-in Ethernet address header for outgoing IP packet. 00776 * 00777 * For IP multicast and broadcast, corresponding Ethernet addresses 00778 * are selected and the packet is transmitted on the link. 00779 * 00780 * For unicast addresses, the packet is submitted to etharp_query(). In 00781 * case the IP address is outside the local network, the IP address of 00782 * the gateway is used. 00783 * 00784 * @param netif The lwIP network interface which the IP packet will be sent on. 00785 * @param q The pbuf(s) containing the IP packet to be sent. 00786 * @param ipaddr The IP address of the packet destination. 00787 * 00788 * @return 00789 * - ERR_RTE No route to destination (no gateway to external networks), 00790 * or the return type of either etharp_query() or etharp_send_ip(). 00791 */ 00792 err_t 00793 etharp_output(struct netif *netif, struct pbuf *q, struct ip_addr *ipaddr) 00794 { 00795 struct eth_addr *dest, mcastaddr; 00796 00797 /* make room for Ethernet header - should not fail */ 00798 if (pbuf_header(q, sizeof(struct eth_hdr)) != 0) { 00799 /* bail out */ 00800 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE | 2, ("etharp_output: could not allocate room for header.\n")); 00801 LINK_STATS_INC(link.lenerr); 00802 return ERR_BUF; 00803 } 00804 00805 /* assume unresolved Ethernet address */ 00806 dest = NULL; 00807 /* Determine on destination hardware address. Broadcasts and multicasts 00808 * are special, other IP addresses are looked up in the ARP table. */ 00809 00810 /* broadcast destination IP address? */ 00811 if (ip_addr_isbroadcast(ipaddr, netif)) { 00812 /* broadcast on Ethernet also */ 00813 dest = (struct eth_addr *)ðbroadcast; 00814 /* multicast destination IP address? */ 00815 } else if (ip_addr_ismulticast(ipaddr)) { 00816 /* Hash IP multicast address to MAC address.*/ 00817 mcastaddr.addr[0] = 0x01; 00818 mcastaddr.addr[1] = 0x00; 00819 mcastaddr.addr[2] = 0x5e; 00820 mcastaddr.addr[3] = ip4_addr2(ipaddr) & 0x7f; 00821 mcastaddr.addr[4] = ip4_addr3(ipaddr); 00822 mcastaddr.addr[5] = ip4_addr4(ipaddr); 00823 /* destination Ethernet address is multicast */ 00824 dest = &mcastaddr; 00825 /* unicast destination IP address? */ 00826 } else { 00827 /* outside local network? */ 00828 if (!ip_addr_netcmp(ipaddr, &(netif->ip_addr), &(netif->netmask))) { 00829 /* interface has default gateway? */ 00830 if (netif->gw.addr != 0) { 00831 /* send to hardware address of default gateway IP address */ 00832 ipaddr = &(netif->gw); 00833 /* no default gateway available */ 00834 } else { 00835 /* no route to destination error (default gateway missing) */ 00836 return ERR_RTE; 00837 } 00838 } 00839 /* queue on destination Ethernet address belonging to ipaddr */ 00840 return etharp_query(netif, ipaddr, q); 00841 } 00842 00843 /* continuation for multicast/broadcast destinations */ 00844 /* obtain source Ethernet address of the given interface */ 00845 /* send packet directly on the link */ 00846 return etharp_send_ip(netif, q, (struct eth_addr*)(netif->hwaddr), dest); 00847 } 00848 00849 /** 00850 * Send an ARP request for the given IP address and/or queue a packet. 00851 * 00852 * If the IP address was not yet in the cache, a pending ARP cache entry 00853 * is added and an ARP request is sent for the given address. The packet 00854 * is queued on this entry. 00855 * 00856 * If the IP address was already pending in the cache, a new ARP request 00857 * is sent for the given address. The packet is queued on this entry. 00858 * 00859 * If the IP address was already stable in the cache, and a packet is 00860 * given, it is directly sent and no ARP request is sent out. 00861 * 00862 * If the IP address was already stable in the cache, and no packet is 00863 * given, an ARP request is sent out. 00864 * 00865 * @param netif The lwIP network interface on which ipaddr 00866 * must be queried for. 00867 * @param ipaddr The IP address to be resolved. 00868 * @param q If non-NULL, a pbuf that must be delivered to the IP address. 00869 * q is not freed by this function. 00870 * 00871 * @note q must only be ONE packet, not a packet queue! 00872 * 00873 * @return 00874 * - ERR_BUF Could not make room for Ethernet header. 00875 * - ERR_MEM Hardware address unknown, and no more ARP entries available 00876 * to query for address or queue the packet. 00877 * - ERR_MEM Could not queue packet due to memory shortage. 00878 * - ERR_RTE No route to destination (no gateway to external networks). 00879 * - ERR_ARG Non-unicast address given, those will not appear in ARP cache. 00880 * 00881 */ 00882 err_t 00883 etharp_query(struct netif *netif, struct ip_addr *ipaddr, struct pbuf *q) 00884 { 00885 struct eth_addr * srcaddr = (struct eth_addr *)netif->hwaddr; 00886 err_t result = ERR_MEM; 00887 s8_t i; /* ARP entry index */ 00888 00889 /* non-unicast address? */ 00890 if (ip_addr_isbroadcast(ipaddr, netif) || 00891 ip_addr_ismulticast(ipaddr) || 00892 ip_addr_isany(ipaddr)) { 00893 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: will not add non-unicast IP address to ARP cache\n")); 00894 return ERR_ARG; 00895 } 00896 00897 /* find entry in ARP cache, ask to create entry if queueing packet */ 00898 #if LWIP_NETIF_HWADDRHINT 00899 i = find_entry(ipaddr, ETHARP_TRY_HARD, netif); 00900 #else /* LWIP_NETIF_HWADDRHINT */ 00901 i = find_entry(ipaddr, ETHARP_TRY_HARD); 00902 #endif /* LWIP_NETIF_HWADDRHINT */ 00903 00904 /* could not find or create entry? */ 00905 if (i < 0) { 00906 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: could not create ARP entry\n")); 00907 if (q) { 00908 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: packet dropped\n")); 00909 ETHARP_STATS_INC(etharp.memerr); 00910 } 00911 return (err_t)i; 00912 } 00913 00914 /* mark a fresh entry as pending (we just sent a request) */ 00915 if (arp_table[i].state == ETHARP_STATE_EMPTY) { 00916 arp_table[i].state = ETHARP_STATE_PENDING; 00917 } 00918 00919 /* { i is either a STABLE or (new or existing) PENDING entry } */ 00920 LWIP_ASSERT("arp_table[i].state == PENDING or STABLE", 00921 ((arp_table[i].state == ETHARP_STATE_PENDING) || 00922 (arp_table[i].state == ETHARP_STATE_STABLE))); 00923 00924 /* do we have a pending entry? or an implicit query request? */ 00925 if ((arp_table[i].state == ETHARP_STATE_PENDING) || (q == NULL)) { 00926 /* try to resolve it; send out ARP request */ 00927 result = etharp_request(netif, ipaddr); 00928 if (result != ERR_OK) { 00929 /* ARP request couldn't be sent */ 00930 /* We don't re-send arp request in etharp_tmr, but we still queue packets, 00931 since this failure could be temporary, and the next packet calling 00932 etharp_query again could lead to sending the queued packets. */ 00933 } 00934 } 00935 00936 /* packet given? */ 00937 if (q != NULL) { 00938 /* stable entry? */ 00939 if (arp_table[i].state == ETHARP_STATE_STABLE) { 00940 /* we have a valid IP->Ethernet address mapping */ 00941 /* send the packet */ 00942 result = etharp_send_ip(netif, q, srcaddr, &(arp_table[i].ethaddr)); 00943 /* pending entry? (either just created or already pending */ 00944 } else if (arp_table[i].state == ETHARP_STATE_PENDING) { 00945 #if ARP_QUEUEING /* queue the given q packet */ 00946 struct pbuf *p; 00947 int copy_needed = 0; 00948 /* IF q includes a PBUF_REF, PBUF_POOL or PBUF_RAM, we have no choice but 00949 * to copy the whole queue into a new PBUF_RAM (see bug #11400) 00950 * PBUF_ROMs can be left as they are, since ROM must not get changed. */ 00951 p = q; 00952 while (p) { 00953 LWIP_ASSERT("no packet queues allowed!", (p->len != p->tot_len) || (p->next == 0)); 00954 if(p->type != PBUF_ROM) { 00955 copy_needed = 1; 00956 break; 00957 } 00958 p = p->next; 00959 } 00960 if(copy_needed) { 00961 /* copy the whole packet into new pbufs */ 00962 p = pbuf_alloc(PBUF_RAW, p->tot_len, PBUF_RAM); 00963 if(p != NULL) { 00964 if (pbuf_copy(p, q) != ERR_OK) { 00965 pbuf_free(p); 00966 p = NULL; 00967 } 00968 } 00969 } else { 00970 /* referencing the old pbuf is enough */ 00971 p = q; 00972 pbuf_ref(p); 00973 } 00974 /* packet could be taken over? */ 00975 if (p != NULL) { 00976 /* queue packet ... */ 00977 struct etharp_q_entry *new_entry; 00978 /* allocate a new arp queue entry */ 00979 new_entry = memp_malloc(MEMP_ARP_QUEUE); 00980 if (new_entry != NULL) { 00981 new_entry->next = 0; 00982 new_entry->p = p; 00983 if(arp_table[i].q != NULL) { 00984 /* queue was already existent, append the new entry to the end */ 00985 struct etharp_q_entry *r; 00986 r = arp_table[i].q; 00987 while (r->next != NULL) { 00988 r = r->next; 00989 } 00990 r->next = new_entry; 00991 } else { 00992 /* queue did not exist, first item in queue */ 00993 arp_table[i].q = new_entry; 00994 } 00995 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: queued packet %p on ARP entry %"S16_F"\n", (void *)q, (s16_t)i)); 00996 result = ERR_OK; 00997 } else { 00998 /* the pool MEMP_ARP_QUEUE is empty */ 00999 pbuf_free(p); 01000 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)); 01001 /* { result == ERR_MEM } through initialization */ 01002 } 01003 } else { 01004 ETHARP_STATS_INC(etharp.memerr); 01005 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)); 01006 /* { result == ERR_MEM } through initialization */ 01007 } 01008 #else /* ARP_QUEUEING == 0 */ 01009 /* q && state == PENDING && ARP_QUEUEING == 0 => result = ERR_MEM */ 01010 /* { result == ERR_MEM } through initialization */ 01011 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_query: Ethernet destination address unknown, queueing disabled, packet %p dropped\n", (void *)q)); 01012 #endif 01013 } 01014 } 01015 return result; 01016 } 01017 01018 /** 01019 * Send a raw ARP packet (opcode and all addresses can be modified) 01020 * 01021 * @param netif the lwip network interface on which to send the ARP packet 01022 * @param ethsrc_addr the source MAC address for the ethernet header 01023 * @param ethdst_addr the destination MAC address for the ethernet header 01024 * @param hwsrc_addr the source MAC address for the ARP protocol header 01025 * @param ipsrc_addr the source IP address for the ARP protocol header 01026 * @param hwdst_addr the destination MAC address for the ARP protocol header 01027 * @param ipdst_addr the destination IP address for the ARP protocol header 01028 * @param opcode the type of the ARP packet 01029 * @return ERR_OK if the ARP packet has been sent 01030 * ERR_MEM if the ARP packet couldn't be allocated 01031 * any other err_t on failure 01032 */ 01033 #if !LWIP_AUTOIP 01034 static 01035 #endif /* LWIP_AUTOIP */ 01036 err_t 01037 etharp_raw(struct netif *netif, const struct eth_addr *ethsrc_addr, 01038 const struct eth_addr *ethdst_addr, 01039 const struct eth_addr *hwsrc_addr, const struct ip_addr *ipsrc_addr, 01040 const struct eth_addr *hwdst_addr, const struct ip_addr *ipdst_addr, 01041 const u16_t opcode) 01042 { 01043 struct pbuf *p; 01044 err_t result = ERR_OK; 01045 u8_t k; /* ARP entry index */ 01046 struct etharp_hdr *hdr; 01047 #if LWIP_AUTOIP 01048 const u8_t * ethdst_hwaddr; 01049 #endif /* LWIP_AUTOIP */ 01050 01051 /* allocate a pbuf for the outgoing ARP request packet */ 01052 p = pbuf_alloc(PBUF_LINK, sizeof(struct etharp_hdr), PBUF_RAM); 01053 /* could allocate a pbuf for an ARP request? */ 01054 if (p == NULL) { 01055 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE | 2, ("etharp_raw: could not allocate pbuf for ARP request.\n")); 01056 ETHARP_STATS_INC(etharp.memerr); 01057 return ERR_MEM; 01058 } 01059 LWIP_ASSERT("check that first pbuf can hold struct etharp_hdr", 01060 (p->len >= sizeof(struct etharp_hdr))); 01061 01062 hdr = static_cast<struct etharp_hdr *>(p->payload); 01063 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_raw: sending raw ARP packet.\n")); 01064 hdr->opcode = htons(opcode); 01065 01066 LWIP_ASSERT("netif->hwaddr_len must be the same as ETHARP_HWADDR_LEN for etharp!", 01067 (netif->hwaddr_len == ETHARP_HWADDR_LEN)); 01068 k = ETHARP_HWADDR_LEN; 01069 #if LWIP_AUTOIP 01070 /* If we are using Link-Local, ARP packets must be broadcast on the 01071 * link layer. (See RFC3927 Section 2.5) */ 01072 ethdst_hwaddr = ((netif->autoip != NULL) && (netif->autoip->state != AUTOIP_STATE_OFF)) ? (u8_t*)(ethbroadcast.addr) : ethdst_addr->addr; 01073 #endif /* LWIP_AUTOIP */ 01074 /* Write MAC-Addresses (combined loop for both headers) */ 01075 while(k > 0) { 01076 k--; 01077 /* Write the ARP MAC-Addresses */ 01078 hdr->shwaddr.addr[k] = hwsrc_addr->addr[k]; 01079 hdr->dhwaddr.addr[k] = hwdst_addr->addr[k]; 01080 /* Write the Ethernet MAC-Addresses */ 01081 #if LWIP_AUTOIP 01082 hdr->ethhdr.dest.addr[k] = ethdst_hwaddr[k]; 01083 #else /* LWIP_AUTOIP */ 01084 hdr->ethhdr.dest.addr[k] = ethdst_addr->addr[k]; 01085 #endif /* LWIP_AUTOIP */ 01086 hdr->ethhdr.src.addr[k] = ethsrc_addr->addr[k]; 01087 } 01088 hdr->sipaddr = *(struct ip_addr2 *)ipsrc_addr; 01089 hdr->dipaddr = *(struct ip_addr2 *)ipdst_addr; 01090 01091 hdr->hwtype = htons(HWTYPE_ETHERNET); 01092 hdr->proto = htons(ETHTYPE_IP); 01093 /* set hwlen and protolen together */ 01094 hdr->_hwlen_protolen = htons((ETHARP_HWADDR_LEN << 8) | sizeof(struct ip_addr)); 01095 01096 hdr->ethhdr.type = htons(ETHTYPE_ARP); 01097 /* send ARP query */ 01098 result = netif->linkoutput(netif, p); 01099 ETHARP_STATS_INC(etharp.xmit); 01100 /* free ARP query packet */ 01101 pbuf_free(p); 01102 p = NULL; 01103 /* could not allocate pbuf for ARP request */ 01104 01105 return result; 01106 } 01107 01108 /** 01109 * Send an ARP request packet asking for ipaddr. 01110 * 01111 * @param netif the lwip network interface on which to send the request 01112 * @param ipaddr the IP address for which to ask 01113 * @return ERR_OK if the request has been sent 01114 * ERR_MEM if the ARP packet couldn't be allocated 01115 * any other err_t on failure 01116 */ 01117 err_t 01118 etharp_request(struct netif *netif, struct ip_addr *ipaddr) 01119 { 01120 LWIP_DEBUGF(ETHARP_DEBUG | LWIP_DBG_TRACE, ("etharp_request: sending ARP request.\n")); 01121 return etharp_raw(netif, (struct eth_addr *)netif->hwaddr, ðbroadcast, 01122 (struct eth_addr *)netif->hwaddr, &netif->ip_addr, ðzero, 01123 ipaddr, ARP_REQUEST); 01124 } 01125 01126 /** 01127 * Process received ethernet frames. Using this function instead of directly 01128 * calling ip_input and passing ARP frames through etharp in ethernetif_input, 01129 * the ARP cache is protected from concurrent access. 01130 * 01131 * @param p the recevied packet, p->payload pointing to the ethernet header 01132 * @param netif the network interface on which the packet was received 01133 */ 01134 err_t 01135 ethernet_input(struct pbuf *p, struct netif *netif) 01136 { 01137 struct eth_hdr* ethhdr; 01138 01139 /* points to packet payload, which starts with an Ethernet header */ 01140 ethhdr = static_cast<struct eth_hdr *>(p->payload); 01141 01142 switch (htons(ethhdr->type)) { 01143 /* IP packet? */ 01144 case ETHTYPE_IP: 01145 #if ETHARP_TRUST_IP_MAC 01146 /* update ARP table */ 01147 etharp_ip_input(netif, p); 01148 #endif /* ETHARP_TRUST_IP_MAC */ 01149 /* skip Ethernet header */ 01150 if(pbuf_header(p, -(s16_t)sizeof(struct eth_hdr))) { 01151 LWIP_ASSERT("Can't move over header in packet", 0); 01152 pbuf_free(p); 01153 p = NULL; 01154 } else { 01155 /* pass to IP layer */ 01156 ip_input(p, netif); 01157 } 01158 break; 01159 01160 case ETHTYPE_ARP: 01161 /* pass p to ARP module */ 01162 etharp_arp_input(netif, (struct eth_addr*)(netif->hwaddr), p); 01163 break; 01164 01165 #if PPPOE_SUPPORT 01166 case ETHTYPE_PPPOEDISC: /* PPP Over Ethernet Discovery Stage */ 01167 pppoe_disc_input(netif, p); 01168 break; 01169 01170 case ETHTYPE_PPPOE: /* PPP Over Ethernet Session Stage */ 01171 pppoe_data_input(netif, p); 01172 break; 01173 #endif /* PPPOE_SUPPORT */ 01174 01175 default: 01176 pbuf_free(p); 01177 p = NULL; 01178 break; 01179 } 01180 01181 /* This means the pbuf is freed or consumed, 01182 so the caller doesn't have to free it again */ 01183 return ERR_OK; 01184 } 01185 #endif /* LWIP_ARP */
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