1 /* 2 * Copyright (c) 1982, 1986, 1988, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 4. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * @(#)if_ether.c 8.1 (Berkeley) 6/10/93 30 * $FreeBSD$ 31 */ 32 33 /* 34 * Ethernet address resolution protocol. 35 * TODO: 36 * add "inuse/lock" bit (or ref. count) along with valid bit 37 */ 38 39 #include "opt_inet.h" 40 #include "opt_bdg.h" 41 #include "opt_mac.h" 42 43 #include <sys/param.h> 44 #include <sys/kernel.h> 45 #include <sys/queue.h> 46 #include <sys/sysctl.h> 47 #include <sys/systm.h> 48 #include <sys/mac.h> 49 #include <sys/mbuf.h> 50 #include <sys/malloc.h> 51 #include <sys/socket.h> 52 #include <sys/syslog.h> 53 54 #include <net/if.h> 55 #include <net/if_dl.h> 56 #include <net/if_types.h> 57 #include <net/route.h> 58 #include <net/netisr.h> 59 #include <net/if_llc.h> 60 #ifdef BRIDGE 61 #include <net/ethernet.h> 62 #include <net/bridge.h> 63 #endif 64 65 #include <netinet/in.h> 66 #include <netinet/in_var.h> 67 #include <netinet/if_ether.h> 68 69 #include <net/if_arc.h> 70 #include <net/iso88025.h> 71 72 #define SIN(s) ((struct sockaddr_in *)s) 73 #define SDL(s) ((struct sockaddr_dl *)s) 74 75 SYSCTL_DECL(_net_link_ether); 76 SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, ""); 77 78 /* timer values */ 79 static int arpt_prune = (5*60*1); /* walk list every 5 minutes */ 80 static int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */ 81 static int arpt_down = 20; /* once declared down, don't send for 20 sec */ 82 83 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, prune_intvl, CTLFLAG_RW, 84 &arpt_prune, 0, ""); 85 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW, 86 &arpt_keep, 0, ""); 87 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, host_down_time, CTLFLAG_RW, 88 &arpt_down, 0, ""); 89 90 #define rt_expire rt_rmx.rmx_expire 91 92 struct llinfo_arp { 93 LIST_ENTRY(llinfo_arp) la_le; 94 struct rtentry *la_rt; 95 struct mbuf *la_hold; /* last packet until resolved/timeout */ 96 u_short la_preempt; /* countdown for pre-expiry arps */ 97 u_short la_asked; /* #times we QUERIED following expiration */ 98 #define la_timer la_rt->rt_rmx.rmx_expire /* deletion time in seconds */ 99 }; 100 101 static LIST_HEAD(, llinfo_arp) llinfo_arp; 102 103 static struct ifqueue arpintrq; 104 static int arp_allocated; 105 106 static int arp_maxtries = 5; 107 static int useloopback = 1; /* use loopback interface for local traffic */ 108 static int arp_proxyall = 0; 109 static struct callout arp_callout; 110 111 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW, 112 &arp_maxtries, 0, ""); 113 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW, 114 &useloopback, 0, ""); 115 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW, 116 &arp_proxyall, 0, ""); 117 118 static void arp_init(void); 119 static void arp_rtrequest(int, struct rtentry *, struct rt_addrinfo *); 120 static void arprequest(struct ifnet *, 121 struct in_addr *, struct in_addr *, u_char *); 122 static void arpintr(struct mbuf *); 123 static void arptfree(struct llinfo_arp *); 124 static void arptimer(void *); 125 static struct llinfo_arp 126 *arplookup(u_long, int, int); 127 #ifdef INET 128 static void in_arpinput(struct mbuf *); 129 #endif 130 131 /* 132 * Timeout routine. Age arp_tab entries periodically. 133 */ 134 /* ARGSUSED */ 135 static void 136 arptimer(ignored_arg) 137 void *ignored_arg; 138 { 139 struct llinfo_arp *la, *ola; 140 141 RADIX_NODE_HEAD_LOCK(rt_tables[AF_INET]); 142 la = LIST_FIRST(&llinfo_arp); 143 while (la != NULL) { 144 struct rtentry *rt = la->la_rt; 145 ola = la; 146 la = LIST_NEXT(la, la_le); 147 if (rt->rt_expire && rt->rt_expire <= time_second) 148 arptfree(ola); /* timer has expired, clear */ 149 } 150 RADIX_NODE_HEAD_UNLOCK(rt_tables[AF_INET]); 151 152 callout_reset(&arp_callout, arpt_prune * hz, arptimer, NULL); 153 } 154 155 /* 156 * Parallel to llc_rtrequest. 157 */ 158 static void 159 arp_rtrequest(req, rt, info) 160 int req; 161 struct rtentry *rt; 162 struct rt_addrinfo *info; 163 { 164 struct sockaddr *gate; 165 struct llinfo_arp *la; 166 static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK}; 167 168 RT_LOCK_ASSERT(rt); 169 170 if (rt->rt_flags & RTF_GATEWAY) 171 return; 172 gate = rt->rt_gateway; 173 la = (struct llinfo_arp *)rt->rt_llinfo; 174 switch (req) { 175 176 case RTM_ADD: 177 /* 178 * XXX: If this is a manually added route to interface 179 * such as older version of routed or gated might provide, 180 * restore cloning bit. 181 */ 182 if ((rt->rt_flags & RTF_HOST) == 0 && 183 SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff) 184 rt->rt_flags |= RTF_CLONING; 185 if (rt->rt_flags & RTF_CLONING) { 186 /* 187 * Case 1: This route should come from a route to iface. 188 */ 189 rt_setgate(rt, rt_key(rt), 190 (struct sockaddr *)&null_sdl); 191 gate = rt->rt_gateway; 192 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 193 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 194 rt->rt_expire = time_second; 195 break; 196 } 197 /* Announce a new entry if requested. */ 198 if (rt->rt_flags & RTF_ANNOUNCE) 199 arprequest(rt->rt_ifp, 200 &SIN(rt_key(rt))->sin_addr, 201 &SIN(rt_key(rt))->sin_addr, 202 (u_char *)LLADDR(SDL(gate))); 203 /*FALLTHROUGH*/ 204 case RTM_RESOLVE: 205 if (gate->sa_family != AF_LINK || 206 gate->sa_len < sizeof(null_sdl)) { 207 log(LOG_DEBUG, "%s: bad gateway %s%s\n", __func__, 208 inet_ntoa(SIN(rt_key(rt))->sin_addr), 209 (gate->sa_family != AF_LINK) ? 210 " (!AF_LINK)": ""); 211 break; 212 } 213 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 214 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 215 if (la != 0) 216 break; /* This happens on a route change */ 217 /* 218 * Case 2: This route may come from cloning, or a manual route 219 * add with a LL address. 220 */ 221 R_Zalloc(la, struct llinfo_arp *, sizeof(*la)); 222 rt->rt_llinfo = (caddr_t)la; 223 if (la == 0) { 224 log(LOG_DEBUG, "%s: malloc failed\n", __func__); 225 break; 226 } 227 arp_allocated++; 228 la->la_rt = rt; 229 rt->rt_flags |= RTF_LLINFO; 230 RADIX_NODE_HEAD_LOCK_ASSERT(rt_tables[AF_INET]); 231 LIST_INSERT_HEAD(&llinfo_arp, la, la_le); 232 233 #ifdef INET 234 /* 235 * This keeps the multicast addresses from showing up 236 * in `arp -a' listings as unresolved. It's not actually 237 * functional. Then the same for broadcast. 238 */ 239 if (IN_MULTICAST(ntohl(SIN(rt_key(rt))->sin_addr.s_addr)) && 240 rt->rt_ifp->if_type != IFT_ARCNET) { 241 ETHER_MAP_IP_MULTICAST(&SIN(rt_key(rt))->sin_addr, 242 LLADDR(SDL(gate))); 243 SDL(gate)->sdl_alen = 6; 244 rt->rt_expire = 0; 245 } 246 if (in_broadcast(SIN(rt_key(rt))->sin_addr, rt->rt_ifp)) { 247 memcpy(LLADDR(SDL(gate)), rt->rt_ifp->if_broadcastaddr, 248 rt->rt_ifp->if_addrlen); 249 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen; 250 rt->rt_expire = 0; 251 } 252 #endif 253 254 if (SIN(rt_key(rt))->sin_addr.s_addr == 255 (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) { 256 /* 257 * This test used to be 258 * if (loif.if_flags & IFF_UP) 259 * It allowed local traffic to be forced 260 * through the hardware by configuring the loopback down. 261 * However, it causes problems during network configuration 262 * for boards that can't receive packets they send. 263 * It is now necessary to clear "useloopback" and remove 264 * the route to force traffic out to the hardware. 265 */ 266 rt->rt_expire = 0; 267 bcopy(IF_LLADDR(rt->rt_ifp), LLADDR(SDL(gate)), 268 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen); 269 if (useloopback) 270 rt->rt_ifp = loif; 271 272 } 273 break; 274 275 case RTM_DELETE: 276 if (la == 0) 277 break; 278 RADIX_NODE_HEAD_LOCK_ASSERT(rt_tables[AF_INET]); 279 LIST_REMOVE(la, la_le); 280 rt->rt_llinfo = 0; 281 rt->rt_flags &= ~RTF_LLINFO; 282 if (la->la_hold) 283 m_freem(la->la_hold); 284 Free((caddr_t)la); 285 } 286 } 287 288 /* 289 * Broadcast an ARP request. Caller specifies: 290 * - arp header source ip address 291 * - arp header target ip address 292 * - arp header source ethernet address 293 */ 294 static void 295 arprequest(ifp, sip, tip, enaddr) 296 struct ifnet *ifp; 297 struct in_addr *sip, *tip; 298 u_char *enaddr; 299 { 300 struct mbuf *m; 301 struct arphdr *ah; 302 struct sockaddr sa; 303 304 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 305 return; 306 m->m_len = sizeof(*ah) + 2*sizeof(struct in_addr) + 307 2*ifp->if_data.ifi_addrlen; 308 m->m_pkthdr.len = m->m_len; 309 MH_ALIGN(m, m->m_len); 310 ah = mtod(m, struct arphdr *); 311 bzero((caddr_t)ah, m->m_len); 312 #ifdef MAC 313 mac_create_mbuf_linklayer(ifp, m); 314 #endif 315 ah->ar_pro = htons(ETHERTYPE_IP); 316 ah->ar_hln = ifp->if_addrlen; /* hardware address length */ 317 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 318 ah->ar_op = htons(ARPOP_REQUEST); 319 bcopy((caddr_t)enaddr, (caddr_t)ar_sha(ah), ah->ar_hln); 320 bcopy((caddr_t)sip, (caddr_t)ar_spa(ah), ah->ar_pln); 321 bcopy((caddr_t)tip, (caddr_t)ar_tpa(ah), ah->ar_pln); 322 sa.sa_family = AF_ARP; 323 sa.sa_len = 2; 324 m->m_flags |= M_BCAST; 325 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 326 327 return; 328 } 329 330 /* 331 * Resolve an IP address into an ethernet address. 332 * On input: 333 * ifp is the interface we use 334 * dst is the next hop, 335 * rt0 is the route to the final destination (possibly useless) 336 * m is the mbuf 337 * desten is where we want the address. 338 * 339 * On success, desten is filled in and the function returns 0; 340 * If the packet must be held pending resolution, we return EWOULDBLOCK 341 * On other errors, we return the corresponding error code. 342 */ 343 int 344 arpresolve(struct ifnet *ifp, struct rtentry *rt0, struct mbuf *m, 345 struct sockaddr *dst, u_char *desten) 346 { 347 struct llinfo_arp *la = 0; 348 struct sockaddr_dl *sdl; 349 int error; 350 struct rtentry *rt; 351 352 error = rt_check(&rt, &rt0, dst); 353 if (error) { 354 m_freem(m); 355 return error; 356 } 357 358 if (m->m_flags & M_BCAST) { /* broadcast */ 359 (void)memcpy(desten, ifp->if_broadcastaddr, ifp->if_addrlen); 360 return (0); 361 } 362 if (m->m_flags & M_MCAST && ifp->if_type != IFT_ARCNET) {/* multicast */ 363 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); 364 return (0); 365 } 366 if (rt) 367 la = (struct llinfo_arp *)rt->rt_llinfo; 368 if (la == 0) { 369 la = arplookup(SIN(dst)->sin_addr.s_addr, 1, 0); 370 if (la) 371 rt = la->la_rt; 372 } 373 if (la == 0 || rt == 0) { 374 log(LOG_DEBUG, "arpresolve: can't allocate llinfo for %s%s%s\n", 375 inet_ntoa(SIN(dst)->sin_addr), la ? "la" : "", 376 rt ? "rt" : ""); 377 m_freem(m); 378 return (EINVAL); /* XXX */ 379 } 380 sdl = SDL(rt->rt_gateway); 381 /* 382 * Check the address family and length is valid, the address 383 * is resolved; otherwise, try to resolve. 384 */ 385 if ((rt->rt_expire == 0 || rt->rt_expire > time_second) && 386 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 387 /* 388 * If entry has an expiry time and it is approaching, 389 * see if we need to send an ARP request within this 390 * arpt_down interval. 391 */ 392 if ((rt->rt_expire != 0) && 393 (time_second + la->la_preempt > rt->rt_expire)) { 394 arprequest(ifp, 395 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 396 &SIN(dst)->sin_addr, 397 IF_LLADDR(ifp)); 398 la->la_preempt--; 399 } 400 401 bcopy(LLADDR(sdl), desten, sdl->sdl_alen); 402 return (0); 403 } 404 /* 405 * If ARP is disabled or static on this interface, stop. 406 * XXX 407 * Probably should not allocate empty llinfo struct if we are 408 * not going to be sending out an arp request. 409 */ 410 if (ifp->if_flags & (IFF_NOARP | IFF_STATICARP)) { 411 m_freem(m); 412 return (EINVAL); 413 } 414 /* 415 * There is an arptab entry, but no ethernet address 416 * response yet. Replace the held mbuf with this 417 * latest one. 418 */ 419 if (la->la_hold) 420 m_freem(la->la_hold); 421 la->la_hold = m; 422 if (rt->rt_expire) { 423 RT_LOCK(rt); 424 rt->rt_flags &= ~RTF_REJECT; 425 if (la->la_asked == 0 || rt->rt_expire != time_second) { 426 rt->rt_expire = time_second; 427 if (la->la_asked++ < arp_maxtries) { 428 arprequest(ifp, 429 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 430 &SIN(dst)->sin_addr, 431 IF_LLADDR(ifp)); 432 } else { 433 rt->rt_flags |= RTF_REJECT; 434 rt->rt_expire += arpt_down; 435 la->la_asked = 0; 436 la->la_preempt = arp_maxtries; 437 } 438 439 } 440 RT_UNLOCK(rt); 441 } 442 return (EWOULDBLOCK); 443 } 444 445 /* 446 * Common length and type checks are done here, 447 * then the protocol-specific routine is called. 448 */ 449 static void 450 arpintr(struct mbuf *m) 451 { 452 struct arphdr *ar; 453 454 if (m->m_len < sizeof(struct arphdr) && 455 ((m = m_pullup(m, sizeof(struct arphdr))) == NULL)) { 456 log(LOG_ERR, "arp: runt packet -- m_pullup failed\n"); 457 return; 458 } 459 ar = mtod(m, struct arphdr *); 460 461 if (ntohs(ar->ar_hrd) != ARPHRD_ETHER && 462 ntohs(ar->ar_hrd) != ARPHRD_IEEE802 && 463 ntohs(ar->ar_hrd) != ARPHRD_ARCNET && 464 ntohs(ar->ar_hrd) != ARPHRD_IEEE1394) { 465 log(LOG_ERR, "arp: unknown hardware address format (0x%2D)\n", 466 (unsigned char *)&ar->ar_hrd, ""); 467 m_freem(m); 468 return; 469 } 470 471 if (m->m_len < arphdr_len(ar)) { 472 if ((m = m_pullup(m, arphdr_len(ar))) == NULL) { 473 log(LOG_ERR, "arp: runt packet\n"); 474 m_freem(m); 475 return; 476 } 477 ar = mtod(m, struct arphdr *); 478 } 479 480 switch (ntohs(ar->ar_pro)) { 481 #ifdef INET 482 case ETHERTYPE_IP: 483 in_arpinput(m); 484 return; 485 #endif 486 } 487 m_freem(m); 488 } 489 490 #ifdef INET 491 /* 492 * ARP for Internet protocols on 10 Mb/s Ethernet. 493 * Algorithm is that given in RFC 826. 494 * In addition, a sanity check is performed on the sender 495 * protocol address, to catch impersonators. 496 * We no longer handle negotiations for use of trailer protocol: 497 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 498 * along with IP replies if we wanted trailers sent to us, 499 * and also sent them in response to IP replies. 500 * This allowed either end to announce the desire to receive 501 * trailer packets. 502 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 503 * but formerly didn't normally send requests. 504 */ 505 static int log_arp_wrong_iface = 1; 506 static int log_arp_movements = 1; 507 508 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW, 509 &log_arp_wrong_iface, 0, 510 "log arp packets arriving on the wrong interface"); 511 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_movements, CTLFLAG_RW, 512 &log_arp_movements, 0, 513 "log arp replies from MACs different than the one in the cache"); 514 515 516 static void 517 in_arpinput(m) 518 struct mbuf *m; 519 { 520 struct arphdr *ah; 521 struct ifnet *ifp = m->m_pkthdr.rcvif; 522 struct iso88025_header *th = (struct iso88025_header *)0; 523 struct iso88025_sockaddr_dl_data *trld; 524 struct llinfo_arp *la = 0; 525 struct rtentry *rt; 526 struct ifaddr *ifa; 527 struct in_ifaddr *ia; 528 struct sockaddr_dl *sdl; 529 struct sockaddr sa; 530 struct in_addr isaddr, itaddr, myaddr; 531 int op, rif_len; 532 int req_len; 533 534 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 535 if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) { 536 log(LOG_ERR, "in_arp: runt packet -- m_pullup failed\n"); 537 return; 538 } 539 540 ah = mtod(m, struct arphdr *); 541 op = ntohs(ah->ar_op); 542 (void)memcpy(&isaddr, ar_spa(ah), sizeof (isaddr)); 543 (void)memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr)); 544 #ifdef BRIDGE 545 #define BRIDGE_TEST (do_bridge) 546 #else 547 #define BRIDGE_TEST (0) /* cc will optimise the test away */ 548 #endif 549 /* 550 * For a bridge, we want to check the address irrespective 551 * of the receive interface. (This will change slightly 552 * when we have clusters of interfaces). 553 */ 554 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) 555 if ((BRIDGE_TEST || (ia->ia_ifp == ifp)) && 556 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) 557 goto match; 558 LIST_FOREACH(ia, INADDR_HASH(isaddr.s_addr), ia_hash) 559 if ((BRIDGE_TEST || (ia->ia_ifp == ifp)) && 560 isaddr.s_addr == ia->ia_addr.sin_addr.s_addr) 561 goto match; 562 /* 563 * No match, use the first inet address on the receive interface 564 * as a dummy address for the rest of the function. 565 */ 566 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) 567 if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_INET) { 568 ia = ifatoia(ifa); 569 goto match; 570 } 571 /* 572 * If bridging, fall back to using any inet address. 573 */ 574 if (!BRIDGE_TEST || (ia = TAILQ_FIRST(&in_ifaddrhead)) == NULL) 575 goto drop; 576 match: 577 myaddr = ia->ia_addr.sin_addr; 578 if (!bcmp(ar_sha(ah), IF_LLADDR(ifp), ifp->if_addrlen)) 579 goto drop; /* it's from me, ignore it. */ 580 if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) { 581 log(LOG_ERR, 582 "arp: link address is broadcast for IP address %s!\n", 583 inet_ntoa(isaddr)); 584 goto drop; 585 } 586 if (isaddr.s_addr == myaddr.s_addr) { 587 log(LOG_ERR, 588 "arp: %*D is using my IP address %s!\n", 589 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 590 inet_ntoa(isaddr)); 591 itaddr = myaddr; 592 goto reply; 593 } 594 if (ifp->if_flags & IFF_STATICARP) 595 goto reply; 596 la = arplookup(isaddr.s_addr, itaddr.s_addr == myaddr.s_addr, 0); 597 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { 598 /* the following is not an error when doing bridging */ 599 if (!BRIDGE_TEST && rt->rt_ifp != ifp) { 600 if (log_arp_wrong_iface) 601 log(LOG_ERR, "arp: %s is on %s but got reply from %*D on %s\n", 602 inet_ntoa(isaddr), 603 rt->rt_ifp->if_xname, 604 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 605 ifp->if_xname); 606 goto reply; 607 } 608 if (sdl->sdl_alen && 609 bcmp(ar_sha(ah), LLADDR(sdl), sdl->sdl_alen)) { 610 if (rt->rt_expire) { 611 if (log_arp_movements) 612 log(LOG_INFO, "arp: %s moved from %*D to %*D on %s\n", 613 inet_ntoa(isaddr), 614 ifp->if_addrlen, (u_char *)LLADDR(sdl), ":", 615 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 616 ifp->if_xname); 617 } else { 618 log(LOG_ERR, 619 "arp: %*D attempts to modify permanent entry for %s on %s\n", 620 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 621 inet_ntoa(isaddr), ifp->if_xname); 622 goto reply; 623 } 624 } 625 /* 626 * sanity check for the address length. 627 * XXX this does not work for protocols with variable address 628 * length. -is 629 */ 630 if (sdl->sdl_alen && 631 sdl->sdl_alen != ah->ar_hln) { 632 log(LOG_WARNING, 633 "arp from %*D: new addr len %d, was %d", 634 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 635 ah->ar_hln, sdl->sdl_alen); 636 } 637 if (ifp->if_addrlen != ah->ar_hln) { 638 log(LOG_WARNING, 639 "arp from %*D: addr len: new %d, i/f %d (ignored)", 640 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 641 ah->ar_hln, ifp->if_addrlen); 642 goto reply; 643 } 644 (void)memcpy(LLADDR(sdl), ar_sha(ah), 645 sdl->sdl_alen = ah->ar_hln); 646 /* 647 * If we receive an arp from a token-ring station over 648 * a token-ring nic then try to save the source 649 * routing info. 650 */ 651 if (ifp->if_type == IFT_ISO88025) { 652 th = (struct iso88025_header *)m->m_pkthdr.header; 653 trld = SDL_ISO88025(sdl); 654 rif_len = TR_RCF_RIFLEN(th->rcf); 655 if ((th->iso88025_shost[0] & TR_RII) && 656 (rif_len > 2)) { 657 trld->trld_rcf = th->rcf; 658 trld->trld_rcf ^= htons(TR_RCF_DIR); 659 memcpy(trld->trld_route, th->rd, rif_len - 2); 660 trld->trld_rcf &= ~htons(TR_RCF_BCST_MASK); 661 /* 662 * Set up source routing information for 663 * reply packet (XXX) 664 */ 665 m->m_data -= rif_len; 666 m->m_len += rif_len; 667 m->m_pkthdr.len += rif_len; 668 } else { 669 th->iso88025_shost[0] &= ~TR_RII; 670 trld->trld_rcf = 0; 671 } 672 m->m_data -= 8; 673 m->m_len += 8; 674 m->m_pkthdr.len += 8; 675 th->rcf = trld->trld_rcf; 676 } 677 RT_LOCK(rt); 678 if (rt->rt_expire) 679 rt->rt_expire = time_second + arpt_keep; 680 rt->rt_flags &= ~RTF_REJECT; 681 RT_UNLOCK(rt); 682 la->la_asked = 0; 683 la->la_preempt = arp_maxtries; 684 if (la->la_hold) { 685 (*ifp->if_output)(ifp, la->la_hold, rt_key(rt), rt); 686 la->la_hold = 0; 687 } 688 } 689 reply: 690 if (op != ARPOP_REQUEST) 691 goto drop; 692 if (itaddr.s_addr == myaddr.s_addr) { 693 /* I am the target */ 694 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 695 (void)memcpy(ar_sha(ah), IF_LLADDR(ifp), ah->ar_hln); 696 } else { 697 la = arplookup(itaddr.s_addr, 0, SIN_PROXY); 698 if (la == NULL) { 699 struct sockaddr_in sin; 700 701 if (!arp_proxyall) 702 goto drop; 703 704 bzero(&sin, sizeof sin); 705 sin.sin_family = AF_INET; 706 sin.sin_len = sizeof sin; 707 sin.sin_addr = itaddr; 708 709 rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL); 710 if (!rt) 711 goto drop; 712 /* 713 * Don't send proxies for nodes on the same interface 714 * as this one came out of, or we'll get into a fight 715 * over who claims what Ether address. 716 */ 717 if (rt->rt_ifp == ifp) { 718 rtfree(rt); 719 goto drop; 720 } 721 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 722 (void)memcpy(ar_sha(ah), IF_LLADDR(ifp), ah->ar_hln); 723 rtfree(rt); 724 725 /* 726 * Also check that the node which sent the ARP packet 727 * is on the the interface we expect it to be on. This 728 * avoids ARP chaos if an interface is connected to the 729 * wrong network. 730 */ 731 sin.sin_addr = isaddr; 732 733 rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL); 734 if (!rt) 735 goto drop; 736 if (rt->rt_ifp != ifp) { 737 log(LOG_INFO, "arp_proxy: ignoring request" 738 " from %s via %s, expecting %s\n", 739 inet_ntoa(isaddr), ifp->if_xname, 740 rt->rt_ifp->if_xname); 741 rtfree(rt); 742 goto drop; 743 } 744 rtfree(rt); 745 746 #ifdef DEBUG_PROXY 747 printf("arp: proxying for %s\n", 748 inet_ntoa(itaddr)); 749 #endif 750 } else { 751 rt = la->la_rt; 752 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 753 sdl = SDL(rt->rt_gateway); 754 (void)memcpy(ar_sha(ah), LLADDR(sdl), ah->ar_hln); 755 } 756 } 757 758 (void)memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln); 759 (void)memcpy(ar_spa(ah), &itaddr, ah->ar_pln); 760 ah->ar_op = htons(ARPOP_REPLY); 761 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 762 m->m_flags &= ~(M_BCAST|M_MCAST); /* never reply by broadcast */ 763 m->m_len = sizeof(*ah) + (2 * ah->ar_pln) + (2 * ah->ar_hln); 764 m->m_pkthdr.len = m->m_len; 765 sa.sa_family = AF_ARP; 766 sa.sa_len = 2; 767 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 768 return; 769 770 drop: 771 m_freem(m); 772 } 773 #endif 774 775 /* 776 * Free an arp entry. 777 */ 778 static void 779 arptfree(la) 780 struct llinfo_arp *la; 781 { 782 struct rtentry *rt = la->la_rt; 783 struct sockaddr_dl *sdl; 784 785 if (rt == 0) 786 panic("arptfree"); 787 if (rt->rt_refcnt > 0 && (sdl = SDL(rt->rt_gateway)) && 788 sdl->sdl_family == AF_LINK) { 789 sdl->sdl_alen = 0; 790 la->la_preempt = la->la_asked = 0; 791 RT_LOCK(rt); /* XXX needed or move higher? */ 792 rt->rt_flags &= ~RTF_REJECT; 793 RT_UNLOCK(rt); 794 return; 795 } 796 rtrequest(RTM_DELETE, rt_key(rt), (struct sockaddr *)0, rt_mask(rt), 797 0, (struct rtentry **)0); 798 } 799 /* 800 * Lookup or enter a new address in arptab. 801 */ 802 static struct llinfo_arp * 803 arplookup(addr, create, proxy) 804 u_long addr; 805 int create, proxy; 806 { 807 struct rtentry *rt; 808 struct sockaddr_inarp sin; 809 const char *why = 0; 810 811 bzero(&sin, sizeof(sin)); 812 sin.sin_len = sizeof(sin); 813 sin.sin_family = AF_INET; 814 sin.sin_addr.s_addr = addr; 815 if (proxy) 816 sin.sin_other = SIN_PROXY; 817 rt = rtalloc1((struct sockaddr *)&sin, create, 0UL); 818 if (rt == 0) 819 return (0); 820 821 if (rt->rt_flags & RTF_GATEWAY) 822 why = "host is not on local network"; 823 else if ((rt->rt_flags & RTF_LLINFO) == 0) 824 why = "could not allocate llinfo"; 825 else if (rt->rt_gateway->sa_family != AF_LINK) 826 why = "gateway route is not ours"; 827 828 if (why) { 829 #define ISDYNCLONE(_rt) \ 830 (((_rt)->rt_flags & (RTF_STATIC | RTF_WASCLONED)) == RTF_WASCLONED) 831 if (create) 832 log(LOG_DEBUG, "arplookup %s failed: %s\n", 833 inet_ntoa(sin.sin_addr), why); 834 /* 835 * If there are no references to this Layer 2 route, 836 * and it is a cloned route, and not static, and 837 * arplookup() is creating the route, then purge 838 * it from the routing table as it is probably bogus. 839 */ 840 if (rt->rt_refcnt == 1 && ISDYNCLONE(rt)) 841 rtexpunge(rt); 842 RTFREE_LOCKED(rt); 843 return (0); 844 #undef ISDYNCLONE 845 } else { 846 RT_REMREF(rt); 847 RT_UNLOCK(rt); 848 return ((struct llinfo_arp *)rt->rt_llinfo); 849 } 850 } 851 852 void 853 arp_ifinit(ifp, ifa) 854 struct ifnet *ifp; 855 struct ifaddr *ifa; 856 { 857 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY) 858 arprequest(ifp, &IA_SIN(ifa)->sin_addr, 859 &IA_SIN(ifa)->sin_addr, IF_LLADDR(ifp)); 860 ifa->ifa_rtrequest = arp_rtrequest; 861 ifa->ifa_flags |= RTF_CLONING; 862 } 863 864 static void 865 arp_init(void) 866 { 867 868 arpintrq.ifq_maxlen = 50; 869 mtx_init(&arpintrq.ifq_mtx, "arp_inq", NULL, MTX_DEF); 870 LIST_INIT(&llinfo_arp); 871 callout_init(&arp_callout, CALLOUT_MPSAFE); 872 netisr_register(NETISR_ARP, arpintr, &arpintrq, NETISR_MPSAFE); 873 callout_reset(&arp_callout, hz, arptimer, NULL); 874 } 875 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0); 876