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 #include "opt_carp.h" 43 44 #include <sys/param.h> 45 #include <sys/kernel.h> 46 #include <sys/queue.h> 47 #include <sys/sysctl.h> 48 #include <sys/systm.h> 49 #include <sys/mac.h> 50 #include <sys/mbuf.h> 51 #include <sys/malloc.h> 52 #include <sys/socket.h> 53 #include <sys/syslog.h> 54 55 #include <net/if.h> 56 #include <net/if_dl.h> 57 #include <net/if_types.h> 58 #include <net/route.h> 59 #include <net/netisr.h> 60 #include <net/if_llc.h> 61 #include <net/ethernet.h> 62 #include <net/bridge.h> 63 64 #include <netinet/in.h> 65 #include <netinet/in_var.h> 66 #include <netinet/if_ether.h> 67 68 #include <net/if_arc.h> 69 #include <net/iso88025.h> 70 71 #ifdef DEV_CARP 72 #include <netinet/ip_carp.h> 73 #endif 74 75 #define SIN(s) ((struct sockaddr_in *)s) 76 #define SDL(s) ((struct sockaddr_dl *)s) 77 78 SYSCTL_DECL(_net_link_ether); 79 SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, ""); 80 81 /* timer values */ 82 static int arpt_prune = (5*60*1); /* walk list every 5 minutes */ 83 static int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */ 84 static int arpt_down = 20; /* once declared down, don't send for 20 sec */ 85 86 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, prune_intvl, CTLFLAG_RW, 87 &arpt_prune, 0, ""); 88 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW, 89 &arpt_keep, 0, ""); 90 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, host_down_time, CTLFLAG_RW, 91 &arpt_down, 0, ""); 92 93 #define rt_expire rt_rmx.rmx_expire 94 95 struct llinfo_arp { 96 LIST_ENTRY(llinfo_arp) la_le; 97 struct rtentry *la_rt; 98 struct mbuf *la_hold; /* last packet until resolved/timeout */ 99 u_short la_preempt; /* countdown for pre-expiry arps */ 100 u_short la_asked; /* #times we QUERIED following expiration */ 101 #define la_timer la_rt->rt_rmx.rmx_expire /* deletion time in seconds */ 102 }; 103 104 static LIST_HEAD(, llinfo_arp) llinfo_arp; 105 106 static struct ifqueue arpintrq; 107 static int arp_allocated; 108 109 static int arp_maxtries = 5; 110 static int useloopback = 1; /* use loopback interface for local traffic */ 111 static int arp_proxyall = 0; 112 static struct callout arp_callout; 113 114 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW, 115 &arp_maxtries, 0, ""); 116 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW, 117 &useloopback, 0, ""); 118 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW, 119 &arp_proxyall, 0, ""); 120 121 static void arp_init(void); 122 static void arp_rtrequest(int, struct rtentry *, struct rt_addrinfo *); 123 static void arprequest(struct ifnet *, 124 struct in_addr *, struct in_addr *, u_char *); 125 static void arpintr(struct mbuf *); 126 static void arptimer(void *); 127 static struct rtentry 128 *arplookup(u_long, int, int); 129 #ifdef INET 130 static void in_arpinput(struct mbuf *); 131 #endif 132 133 /* 134 * Timeout routine. Age arp_tab entries periodically. 135 */ 136 /* ARGSUSED */ 137 static void 138 arptimer(void * __unused unused) 139 { 140 struct llinfo_arp *la, *ola; 141 142 RADIX_NODE_HEAD_LOCK(rt_tables[AF_INET]); 143 LIST_FOREACH_SAFE(la, &llinfo_arp, la_le, ola) { 144 struct rtentry *rt = la->la_rt; 145 146 RT_LOCK(rt); 147 if (rt->rt_expire && rt->rt_expire <= time_second) { 148 struct sockaddr_dl *sdl = SDL(rt->rt_gateway); 149 150 KASSERT(sdl->sdl_family == AF_LINK, ("sdl_family %d", 151 sdl->sdl_family)); 152 if (rt->rt_refcnt > 1) { 153 sdl->sdl_alen = 0; 154 la->la_preempt = la->la_asked = 0; 155 rt->rt_flags &= ~RTF_REJECT; 156 RT_UNLOCK(rt); 157 continue; 158 } 159 RT_UNLOCK(rt); 160 /* 161 * XXX: LIST_REMOVE() is deep inside rtrequest(). 162 */ 163 rtrequest(RTM_DELETE, rt_key(rt), NULL, rt_mask(rt), 0, 164 NULL); 165 continue; 166 } 167 RT_UNLOCK(rt); 168 } 169 RADIX_NODE_HEAD_UNLOCK(rt_tables[AF_INET]); 170 171 callout_reset(&arp_callout, arpt_prune * hz, arptimer, NULL); 172 } 173 174 /* 175 * Parallel to llc_rtrequest. 176 */ 177 static void 178 arp_rtrequest(req, rt, info) 179 int req; 180 struct rtentry *rt; 181 struct rt_addrinfo *info; 182 { 183 struct sockaddr *gate; 184 struct llinfo_arp *la; 185 static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK}; 186 struct in_ifaddr *ia; 187 struct ifaddr *ifa; 188 189 RT_LOCK_ASSERT(rt); 190 191 if (rt->rt_flags & RTF_GATEWAY) 192 return; 193 gate = rt->rt_gateway; 194 la = (struct llinfo_arp *)rt->rt_llinfo; 195 switch (req) { 196 197 case RTM_ADD: 198 /* 199 * XXX: If this is a manually added route to interface 200 * such as older version of routed or gated might provide, 201 * restore cloning bit. 202 */ 203 if ((rt->rt_flags & RTF_HOST) == 0 && 204 rt_mask(rt) != NULL && 205 SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff) 206 rt->rt_flags |= RTF_CLONING; 207 if (rt->rt_flags & RTF_CLONING) { 208 /* 209 * Case 1: This route should come from a route to iface. 210 */ 211 rt_setgate(rt, rt_key(rt), 212 (struct sockaddr *)&null_sdl); 213 gate = rt->rt_gateway; 214 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 215 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 216 rt->rt_expire = time_second; 217 break; 218 } 219 /* Announce a new entry if requested. */ 220 if (rt->rt_flags & RTF_ANNOUNCE) 221 arprequest(rt->rt_ifp, 222 &SIN(rt_key(rt))->sin_addr, 223 &SIN(rt_key(rt))->sin_addr, 224 (u_char *)LLADDR(SDL(gate))); 225 /*FALLTHROUGH*/ 226 case RTM_RESOLVE: 227 if (gate->sa_family != AF_LINK || 228 gate->sa_len < sizeof(null_sdl)) { 229 log(LOG_DEBUG, "%s: bad gateway %s%s\n", __func__, 230 inet_ntoa(SIN(rt_key(rt))->sin_addr), 231 (gate->sa_family != AF_LINK) ? 232 " (!AF_LINK)": ""); 233 break; 234 } 235 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 236 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 237 if (la != 0) 238 break; /* This happens on a route change */ 239 /* 240 * Case 2: This route may come from cloning, or a manual route 241 * add with a LL address. 242 */ 243 R_Zalloc(la, struct llinfo_arp *, sizeof(*la)); 244 rt->rt_llinfo = (caddr_t)la; 245 if (la == 0) { 246 log(LOG_DEBUG, "%s: malloc failed\n", __func__); 247 break; 248 } 249 arp_allocated++; 250 /* 251 * We are storing a route entry outside of radix tree. So, 252 * it can be found and accessed by other means than radix 253 * lookup. The routing code assumes that any rtentry detached 254 * from radix can be destroyed safely. To prevent this, we 255 * add an additional reference. 256 */ 257 RT_ADDREF(rt); 258 la->la_rt = rt; 259 rt->rt_flags |= RTF_LLINFO; 260 RADIX_NODE_HEAD_LOCK_ASSERT(rt_tables[AF_INET]); 261 LIST_INSERT_HEAD(&llinfo_arp, la, la_le); 262 263 #ifdef INET 264 /* 265 * This keeps the multicast addresses from showing up 266 * in `arp -a' listings as unresolved. It's not actually 267 * functional. Then the same for broadcast. 268 */ 269 if (IN_MULTICAST(ntohl(SIN(rt_key(rt))->sin_addr.s_addr)) && 270 rt->rt_ifp->if_type != IFT_ARCNET) { 271 ETHER_MAP_IP_MULTICAST(&SIN(rt_key(rt))->sin_addr, 272 LLADDR(SDL(gate))); 273 SDL(gate)->sdl_alen = 6; 274 rt->rt_expire = 0; 275 } 276 if (in_broadcast(SIN(rt_key(rt))->sin_addr, rt->rt_ifp)) { 277 memcpy(LLADDR(SDL(gate)), rt->rt_ifp->if_broadcastaddr, 278 rt->rt_ifp->if_addrlen); 279 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen; 280 rt->rt_expire = 0; 281 } 282 #endif 283 284 TAILQ_FOREACH(ia, &in_ifaddrhead, ia_link) { 285 if (ia->ia_ifp == rt->rt_ifp && 286 SIN(rt_key(rt))->sin_addr.s_addr == 287 (IA_SIN(ia))->sin_addr.s_addr) 288 break; 289 } 290 if (ia) { 291 /* 292 * This test used to be 293 * if (loif.if_flags & IFF_UP) 294 * It allowed local traffic to be forced 295 * through the hardware by configuring the loopback down. 296 * However, it causes problems during network configuration 297 * for boards that can't receive packets they send. 298 * It is now necessary to clear "useloopback" and remove 299 * the route to force traffic out to the hardware. 300 */ 301 rt->rt_expire = 0; 302 bcopy(IF_LLADDR(rt->rt_ifp), LLADDR(SDL(gate)), 303 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen); 304 if (useloopback) 305 rt->rt_ifp = loif; 306 307 /* 308 * make sure to set rt->rt_ifa to the interface 309 * address we are using, otherwise we will have trouble 310 * with source address selection. 311 */ 312 ifa = &ia->ia_ifa; 313 if (ifa != rt->rt_ifa) { 314 IFAFREE(rt->rt_ifa); 315 IFAREF(ifa); 316 rt->rt_ifa = ifa; 317 } 318 } 319 break; 320 321 case RTM_DELETE: 322 if (la == 0) 323 break; 324 RADIX_NODE_HEAD_LOCK_ASSERT(rt_tables[AF_INET]); 325 LIST_REMOVE(la, la_le); 326 RT_REMREF(rt); 327 rt->rt_llinfo = 0; 328 rt->rt_flags &= ~RTF_LLINFO; 329 if (la->la_hold) 330 m_freem(la->la_hold); 331 Free((caddr_t)la); 332 } 333 } 334 335 /* 336 * Broadcast an ARP request. Caller specifies: 337 * - arp header source ip address 338 * - arp header target ip address 339 * - arp header source ethernet address 340 */ 341 static void 342 arprequest(ifp, sip, tip, enaddr) 343 struct ifnet *ifp; 344 struct in_addr *sip, *tip; 345 u_char *enaddr; 346 { 347 struct mbuf *m; 348 struct arphdr *ah; 349 struct sockaddr sa; 350 351 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 352 return; 353 m->m_len = sizeof(*ah) + 2*sizeof(struct in_addr) + 354 2*ifp->if_data.ifi_addrlen; 355 m->m_pkthdr.len = m->m_len; 356 MH_ALIGN(m, m->m_len); 357 ah = mtod(m, struct arphdr *); 358 bzero((caddr_t)ah, m->m_len); 359 #ifdef MAC 360 mac_create_mbuf_linklayer(ifp, m); 361 #endif 362 ah->ar_pro = htons(ETHERTYPE_IP); 363 ah->ar_hln = ifp->if_addrlen; /* hardware address length */ 364 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 365 ah->ar_op = htons(ARPOP_REQUEST); 366 bcopy((caddr_t)enaddr, (caddr_t)ar_sha(ah), ah->ar_hln); 367 bcopy((caddr_t)sip, (caddr_t)ar_spa(ah), ah->ar_pln); 368 bcopy((caddr_t)tip, (caddr_t)ar_tpa(ah), ah->ar_pln); 369 sa.sa_family = AF_ARP; 370 sa.sa_len = 2; 371 m->m_flags |= M_BCAST; 372 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 373 374 return; 375 } 376 377 /* 378 * Resolve an IP address into an ethernet address. 379 * On input: 380 * ifp is the interface we use 381 * dst is the next hop, 382 * rt0 is the route to the final destination (possibly useless) 383 * m is the mbuf 384 * desten is where we want the address. 385 * 386 * On success, desten is filled in and the function returns 0; 387 * If the packet must be held pending resolution, we return EWOULDBLOCK 388 * On other errors, we return the corresponding error code. 389 */ 390 int 391 arpresolve(struct ifnet *ifp, struct rtentry *rt0, struct mbuf *m, 392 struct sockaddr *dst, u_char *desten) 393 { 394 struct llinfo_arp *la = NULL; 395 struct rtentry *rt = NULL; 396 struct sockaddr_dl *sdl; 397 int error; 398 399 if (m->m_flags & M_BCAST) { /* broadcast */ 400 (void)memcpy(desten, ifp->if_broadcastaddr, ifp->if_addrlen); 401 return (0); 402 } 403 if (m->m_flags & M_MCAST && ifp->if_type != IFT_ARCNET) {/* multicast */ 404 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); 405 return (0); 406 } 407 408 if (rt0 != NULL) { 409 error = rt_check(&rt, &rt0, dst); 410 if (error) { 411 m_freem(m); 412 return error; 413 } 414 la = (struct llinfo_arp *)rt->rt_llinfo; 415 if (la == NULL) 416 RT_UNLOCK(rt); 417 } 418 if (la == NULL) { 419 /* 420 * We enter this block in case if rt0 was NULL, 421 * or if rt found by rt_check() didn't have llinfo. 422 */ 423 rt = arplookup(SIN(dst)->sin_addr.s_addr, 1, 0); 424 if (rt == NULL) { 425 log(LOG_DEBUG, 426 "arpresolve: can't allocate route for %s\n", 427 inet_ntoa(SIN(dst)->sin_addr)); 428 m_freem(m); 429 return (EINVAL); /* XXX */ 430 } 431 la = (struct llinfo_arp *)rt->rt_llinfo; 432 if (la == NULL) { 433 RT_UNLOCK(rt); 434 log(LOG_DEBUG, 435 "arpresolve: can't allocate llinfo for %s\n", 436 inet_ntoa(SIN(dst)->sin_addr)); 437 m_freem(m); 438 return (EINVAL); /* XXX */ 439 } 440 } 441 sdl = SDL(rt->rt_gateway); 442 /* 443 * Check the address family and length is valid, the address 444 * is resolved; otherwise, try to resolve. 445 */ 446 if ((rt->rt_expire == 0 || rt->rt_expire > time_second) && 447 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 448 /* 449 * If entry has an expiry time and it is approaching, 450 * see if we need to send an ARP request within this 451 * arpt_down interval. 452 */ 453 if ((rt->rt_expire != 0) && 454 (time_second + la->la_preempt > rt->rt_expire)) { 455 arprequest(ifp, 456 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 457 &SIN(dst)->sin_addr, 458 IF_LLADDR(ifp)); 459 la->la_preempt--; 460 } 461 462 bcopy(LLADDR(sdl), desten, sdl->sdl_alen); 463 RT_UNLOCK(rt); 464 return (0); 465 } 466 /* 467 * If ARP is disabled or static on this interface, stop. 468 * XXX 469 * Probably should not allocate empty llinfo struct if we are 470 * not going to be sending out an arp request. 471 */ 472 if (ifp->if_flags & (IFF_NOARP | IFF_STATICARP)) { 473 RT_UNLOCK(rt); 474 m_freem(m); 475 return (EINVAL); 476 } 477 /* 478 * There is an arptab entry, but no ethernet address 479 * response yet. Replace the held mbuf with this 480 * latest one. 481 */ 482 if (la->la_hold) 483 m_freem(la->la_hold); 484 la->la_hold = m; 485 if (rt->rt_expire) { 486 rt->rt_flags &= ~RTF_REJECT; 487 if (la->la_asked == 0 || rt->rt_expire != time_second) { 488 rt->rt_expire = time_second; 489 if (la->la_asked++ < arp_maxtries) { 490 arprequest(ifp, 491 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 492 &SIN(dst)->sin_addr, 493 IF_LLADDR(ifp)); 494 } else { 495 rt->rt_flags |= RTF_REJECT; 496 rt->rt_expire += arpt_down; 497 la->la_asked = 0; 498 la->la_preempt = arp_maxtries; 499 } 500 501 } 502 } 503 RT_UNLOCK(rt); 504 return (EWOULDBLOCK); 505 } 506 507 /* 508 * Common length and type checks are done here, 509 * then the protocol-specific routine is called. 510 */ 511 static void 512 arpintr(struct mbuf *m) 513 { 514 struct arphdr *ar; 515 516 if (m->m_len < sizeof(struct arphdr) && 517 ((m = m_pullup(m, sizeof(struct arphdr))) == NULL)) { 518 log(LOG_ERR, "arp: runt packet -- m_pullup failed\n"); 519 return; 520 } 521 ar = mtod(m, struct arphdr *); 522 523 if (ntohs(ar->ar_hrd) != ARPHRD_ETHER && 524 ntohs(ar->ar_hrd) != ARPHRD_IEEE802 && 525 ntohs(ar->ar_hrd) != ARPHRD_ARCNET && 526 ntohs(ar->ar_hrd) != ARPHRD_IEEE1394) { 527 log(LOG_ERR, "arp: unknown hardware address format (0x%2D)\n", 528 (unsigned char *)&ar->ar_hrd, ""); 529 m_freem(m); 530 return; 531 } 532 533 if (m->m_len < arphdr_len(ar)) { 534 if ((m = m_pullup(m, arphdr_len(ar))) == NULL) { 535 log(LOG_ERR, "arp: runt packet\n"); 536 m_freem(m); 537 return; 538 } 539 ar = mtod(m, struct arphdr *); 540 } 541 542 switch (ntohs(ar->ar_pro)) { 543 #ifdef INET 544 case ETHERTYPE_IP: 545 in_arpinput(m); 546 return; 547 #endif 548 } 549 m_freem(m); 550 } 551 552 #ifdef INET 553 /* 554 * ARP for Internet protocols on 10 Mb/s Ethernet. 555 * Algorithm is that given in RFC 826. 556 * In addition, a sanity check is performed on the sender 557 * protocol address, to catch impersonators. 558 * We no longer handle negotiations for use of trailer protocol: 559 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 560 * along with IP replies if we wanted trailers sent to us, 561 * and also sent them in response to IP replies. 562 * This allowed either end to announce the desire to receive 563 * trailer packets. 564 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 565 * but formerly didn't normally send requests. 566 */ 567 static int log_arp_wrong_iface = 1; 568 static int log_arp_movements = 1; 569 570 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW, 571 &log_arp_wrong_iface, 0, 572 "log arp packets arriving on the wrong interface"); 573 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_movements, CTLFLAG_RW, 574 &log_arp_movements, 0, 575 "log arp replies from MACs different than the one in the cache"); 576 577 578 static void 579 in_arpinput(m) 580 struct mbuf *m; 581 { 582 struct arphdr *ah; 583 struct ifnet *ifp = m->m_pkthdr.rcvif; 584 struct iso88025_header *th = (struct iso88025_header *)0; 585 struct iso88025_sockaddr_dl_data *trld; 586 struct llinfo_arp *la; 587 struct rtentry *rt; 588 struct ifaddr *ifa; 589 struct in_ifaddr *ia; 590 struct sockaddr_dl *sdl; 591 struct sockaddr sa; 592 struct in_addr isaddr, itaddr, myaddr; 593 struct mbuf *hold; 594 u_int8_t *enaddr = NULL; 595 int op, rif_len; 596 int req_len; 597 int bridged = 0; 598 #ifdef DEV_CARP 599 int carp_match = 0; 600 #endif 601 602 if (do_bridge || ifp->if_bridge) 603 bridged = 1; 604 605 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 606 if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) { 607 log(LOG_ERR, "in_arp: runt packet -- m_pullup failed\n"); 608 return; 609 } 610 611 ah = mtod(m, struct arphdr *); 612 op = ntohs(ah->ar_op); 613 (void)memcpy(&isaddr, ar_spa(ah), sizeof (isaddr)); 614 (void)memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr)); 615 616 /* 617 * For a bridge, we want to check the address irrespective 618 * of the receive interface. (This will change slightly 619 * when we have clusters of interfaces). 620 * If the interface does not match, but the recieving interface 621 * is part of carp, we call carp_iamatch to see if this is a 622 * request for the virtual host ip. 623 * XXX: This is really ugly! 624 */ 625 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) { 626 if ((bridged || (ia->ia_ifp == ifp)) && 627 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) 628 goto match; 629 #ifdef DEV_CARP 630 if (ifp->if_carp != NULL && 631 carp_iamatch(ifp->if_carp, ia, &isaddr, &enaddr) && 632 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) { 633 carp_match = 1; 634 goto match; 635 } 636 #endif 637 } 638 LIST_FOREACH(ia, INADDR_HASH(isaddr.s_addr), ia_hash) 639 if ((bridged || (ia->ia_ifp == ifp)) && 640 isaddr.s_addr == ia->ia_addr.sin_addr.s_addr) 641 goto match; 642 /* 643 * No match, use the first inet address on the receive interface 644 * as a dummy address for the rest of the function. 645 */ 646 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) 647 if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_INET) { 648 ia = ifatoia(ifa); 649 goto match; 650 } 651 /* 652 * If bridging, fall back to using any inet address. 653 */ 654 if (!bridged || (ia = TAILQ_FIRST(&in_ifaddrhead)) == NULL) 655 goto drop; 656 match: 657 if (!enaddr) 658 enaddr = (u_int8_t *)IF_LLADDR(ifp); 659 myaddr = ia->ia_addr.sin_addr; 660 if (!bcmp(ar_sha(ah), enaddr, ifp->if_addrlen)) 661 goto drop; /* it's from me, ignore it. */ 662 if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) { 663 log(LOG_ERR, 664 "arp: link address is broadcast for IP address %s!\n", 665 inet_ntoa(isaddr)); 666 goto drop; 667 } 668 /* 669 * Warn if another host is using the same IP address, but only if the 670 * IP address isn't 0.0.0.0, which is used for DHCP only, in which 671 * case we suppress the warning to avoid false positive complaints of 672 * potential misconfiguration. 673 */ 674 if (isaddr.s_addr == myaddr.s_addr && myaddr.s_addr != 0) { 675 log(LOG_ERR, 676 "arp: %*D is using my IP address %s!\n", 677 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 678 inet_ntoa(isaddr)); 679 itaddr = myaddr; 680 goto reply; 681 } 682 if (ifp->if_flags & IFF_STATICARP) 683 goto reply; 684 rt = arplookup(isaddr.s_addr, itaddr.s_addr == myaddr.s_addr, 0); 685 if (rt != NULL) { 686 la = (struct llinfo_arp *)rt->rt_llinfo; 687 if (la == NULL) { 688 RT_UNLOCK(rt); 689 goto reply; 690 } 691 } else 692 goto reply; 693 694 /* The following is not an error when doing bridging. */ 695 if (!bridged && rt->rt_ifp != ifp 696 #ifdef DEV_CARP 697 && (ifp->if_type != IFT_CARP || !carp_match) 698 #endif 699 ) { 700 if (log_arp_wrong_iface) 701 log(LOG_ERR, "arp: %s is on %s but got reply from %*D on %s\n", 702 inet_ntoa(isaddr), 703 rt->rt_ifp->if_xname, 704 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 705 ifp->if_xname); 706 RT_UNLOCK(rt); 707 goto reply; 708 } 709 sdl = SDL(rt->rt_gateway); 710 if (sdl->sdl_alen && 711 bcmp(ar_sha(ah), LLADDR(sdl), sdl->sdl_alen)) { 712 if (rt->rt_expire) { 713 if (log_arp_movements) 714 log(LOG_INFO, "arp: %s moved from %*D to %*D on %s\n", 715 inet_ntoa(isaddr), 716 ifp->if_addrlen, (u_char *)LLADDR(sdl), ":", 717 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 718 ifp->if_xname); 719 } else { 720 log(LOG_ERR, 721 "arp: %*D attempts to modify permanent entry for %s on %s\n", 722 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 723 inet_ntoa(isaddr), ifp->if_xname); 724 RT_UNLOCK(rt); 725 goto reply; 726 } 727 } 728 /* 729 * sanity check for the address length. 730 * XXX this does not work for protocols with variable address 731 * length. -is 732 */ 733 if (sdl->sdl_alen && 734 sdl->sdl_alen != ah->ar_hln) { 735 log(LOG_WARNING, 736 "arp from %*D: new addr len %d, was %d", 737 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 738 ah->ar_hln, sdl->sdl_alen); 739 } 740 if (ifp->if_addrlen != ah->ar_hln) { 741 log(LOG_WARNING, 742 "arp from %*D: addr len: new %d, i/f %d (ignored)", 743 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 744 ah->ar_hln, ifp->if_addrlen); 745 RT_UNLOCK(rt); 746 goto reply; 747 } 748 (void)memcpy(LLADDR(sdl), ar_sha(ah), 749 sdl->sdl_alen = ah->ar_hln); 750 /* 751 * If we receive an arp from a token-ring station over 752 * a token-ring nic then try to save the source 753 * routing info. 754 */ 755 if (ifp->if_type == IFT_ISO88025) { 756 th = (struct iso88025_header *)m->m_pkthdr.header; 757 trld = SDL_ISO88025(sdl); 758 rif_len = TR_RCF_RIFLEN(th->rcf); 759 if ((th->iso88025_shost[0] & TR_RII) && 760 (rif_len > 2)) { 761 trld->trld_rcf = th->rcf; 762 trld->trld_rcf ^= htons(TR_RCF_DIR); 763 memcpy(trld->trld_route, th->rd, rif_len - 2); 764 trld->trld_rcf &= ~htons(TR_RCF_BCST_MASK); 765 /* 766 * Set up source routing information for 767 * reply packet (XXX) 768 */ 769 m->m_data -= rif_len; 770 m->m_len += rif_len; 771 m->m_pkthdr.len += rif_len; 772 } else { 773 th->iso88025_shost[0] &= ~TR_RII; 774 trld->trld_rcf = 0; 775 } 776 m->m_data -= 8; 777 m->m_len += 8; 778 m->m_pkthdr.len += 8; 779 th->rcf = trld->trld_rcf; 780 } 781 if (rt->rt_expire) 782 rt->rt_expire = time_second + arpt_keep; 783 rt->rt_flags &= ~RTF_REJECT; 784 la->la_asked = 0; 785 la->la_preempt = arp_maxtries; 786 hold = la->la_hold; 787 la->la_hold = NULL; 788 RT_UNLOCK(rt); 789 if (hold != NULL) 790 (*ifp->if_output)(ifp, hold, rt_key(rt), rt); 791 792 reply: 793 if (op != ARPOP_REQUEST) 794 goto drop; 795 if (itaddr.s_addr == myaddr.s_addr) { 796 /* I am the target */ 797 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 798 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln); 799 } else { 800 rt = arplookup(itaddr.s_addr, 0, SIN_PROXY); 801 if (rt == NULL) { 802 struct sockaddr_in sin; 803 804 if (!arp_proxyall) 805 goto drop; 806 807 bzero(&sin, sizeof sin); 808 sin.sin_family = AF_INET; 809 sin.sin_len = sizeof sin; 810 sin.sin_addr = itaddr; 811 812 rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL); 813 if (!rt) 814 goto drop; 815 /* 816 * Don't send proxies for nodes on the same interface 817 * as this one came out of, or we'll get into a fight 818 * over who claims what Ether address. 819 */ 820 if (rt->rt_ifp == ifp) { 821 rtfree(rt); 822 goto drop; 823 } 824 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 825 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln); 826 rtfree(rt); 827 828 /* 829 * Also check that the node which sent the ARP packet 830 * is on the the interface we expect it to be on. This 831 * avoids ARP chaos if an interface is connected to the 832 * wrong network. 833 */ 834 sin.sin_addr = isaddr; 835 836 rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL); 837 if (!rt) 838 goto drop; 839 if (rt->rt_ifp != ifp) { 840 log(LOG_INFO, "arp_proxy: ignoring request" 841 " from %s via %s, expecting %s\n", 842 inet_ntoa(isaddr), ifp->if_xname, 843 rt->rt_ifp->if_xname); 844 rtfree(rt); 845 goto drop; 846 } 847 rtfree(rt); 848 849 #ifdef DEBUG_PROXY 850 printf("arp: proxying for %s\n", 851 inet_ntoa(itaddr)); 852 #endif 853 } else { 854 sdl = SDL(rt->rt_gateway); 855 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 856 (void)memcpy(ar_sha(ah), LLADDR(sdl), ah->ar_hln); 857 RT_UNLOCK(rt); 858 } 859 } 860 861 (void)memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln); 862 (void)memcpy(ar_spa(ah), &itaddr, ah->ar_pln); 863 ah->ar_op = htons(ARPOP_REPLY); 864 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 865 m->m_flags &= ~(M_BCAST|M_MCAST); /* never reply by broadcast */ 866 m->m_len = sizeof(*ah) + (2 * ah->ar_pln) + (2 * ah->ar_hln); 867 m->m_pkthdr.len = m->m_len; 868 sa.sa_family = AF_ARP; 869 sa.sa_len = 2; 870 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 871 return; 872 873 drop: 874 m_freem(m); 875 } 876 #endif 877 878 /* 879 * Lookup or enter a new address in arptab. 880 */ 881 static struct rtentry * 882 arplookup(addr, create, proxy) 883 u_long addr; 884 int create, proxy; 885 { 886 struct rtentry *rt; 887 struct sockaddr_inarp sin; 888 const char *why = 0; 889 890 bzero(&sin, sizeof(sin)); 891 sin.sin_len = sizeof(sin); 892 sin.sin_family = AF_INET; 893 sin.sin_addr.s_addr = addr; 894 if (proxy) 895 sin.sin_other = SIN_PROXY; 896 rt = rtalloc1((struct sockaddr *)&sin, create, 0UL); 897 if (rt == 0) 898 return (0); 899 900 if (rt->rt_flags & RTF_GATEWAY) 901 why = "host is not on local network"; 902 else if ((rt->rt_flags & RTF_LLINFO) == 0) 903 why = "could not allocate llinfo"; 904 else if (rt->rt_gateway->sa_family != AF_LINK) 905 why = "gateway route is not ours"; 906 907 if (why) { 908 #define ISDYNCLONE(_rt) \ 909 (((_rt)->rt_flags & (RTF_STATIC | RTF_WASCLONED)) == RTF_WASCLONED) 910 if (create) 911 log(LOG_DEBUG, "arplookup %s failed: %s\n", 912 inet_ntoa(sin.sin_addr), why); 913 /* 914 * If there are no references to this Layer 2 route, 915 * and it is a cloned route, and not static, and 916 * arplookup() is creating the route, then purge 917 * it from the routing table as it is probably bogus. 918 */ 919 if (rt->rt_refcnt == 1 && ISDYNCLONE(rt)) 920 rtexpunge(rt); 921 RTFREE_LOCKED(rt); 922 return (0); 923 #undef ISDYNCLONE 924 } else { 925 RT_REMREF(rt); 926 return (rt); 927 } 928 } 929 930 void 931 arp_ifinit(ifp, ifa) 932 struct ifnet *ifp; 933 struct ifaddr *ifa; 934 { 935 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY) 936 arprequest(ifp, &IA_SIN(ifa)->sin_addr, 937 &IA_SIN(ifa)->sin_addr, IF_LLADDR(ifp)); 938 ifa->ifa_rtrequest = arp_rtrequest; 939 ifa->ifa_flags |= RTF_CLONING; 940 } 941 942 void 943 arp_ifinit2(ifp, ifa, enaddr) 944 struct ifnet *ifp; 945 struct ifaddr *ifa; 946 u_char *enaddr; 947 { 948 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY) 949 arprequest(ifp, &IA_SIN(ifa)->sin_addr, 950 &IA_SIN(ifa)->sin_addr, enaddr); 951 ifa->ifa_rtrequest = arp_rtrequest; 952 ifa->ifa_flags |= RTF_CLONING; 953 } 954 955 static void 956 arp_init(void) 957 { 958 959 arpintrq.ifq_maxlen = 50; 960 mtx_init(&arpintrq.ifq_mtx, "arp_inq", NULL, MTX_DEF); 961 LIST_INIT(&llinfo_arp); 962 callout_init(&arp_callout, CALLOUT_MPSAFE); 963 netisr_register(NETISR_ARP, arpintr, &arpintrq, NETISR_MPSAFE); 964 callout_reset(&arp_callout, hz, arptimer, NULL); 965 } 966 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0); 967