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 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#)if_ether.c 8.1 (Berkeley) 6/10/93 34 * $FreeBSD: src/sys/netinet/if_ether.c,v 1.64.2.23 2003/04/11 07:23:15 fjoe Exp $ 35 * $DragonFly: src/sys/netinet/if_ether.c,v 1.20 2004/12/14 18:46:08 hsu Exp $ 36 */ 37 38 /* 39 * Ethernet address resolution protocol. 40 * TODO: 41 * add "inuse/lock" bit (or ref. count) along with valid bit 42 */ 43 44 #include "opt_inet.h" 45 #include "opt_bdg.h" 46 47 #include <sys/param.h> 48 #include <sys/kernel.h> 49 #include <sys/queue.h> 50 #include <sys/sysctl.h> 51 #include <sys/systm.h> 52 #include <sys/mbuf.h> 53 #include <sys/malloc.h> 54 #include <sys/socket.h> 55 #include <sys/syslog.h> 56 57 #include <sys/thread2.h> 58 #include <sys/msgport2.h> 59 60 #include <net/if.h> 61 #include <net/if_dl.h> 62 #include <net/if_types.h> 63 #include <net/route.h> 64 #include <net/netisr.h> 65 #include <net/if_llc.h> 66 #ifdef BRIDGE 67 #include <net/ethernet.h> 68 #include <net/bridge/bridge.h> 69 #endif 70 71 #include <netinet/in.h> 72 #include <netinet/in_var.h> 73 #include <netinet/if_ether.h> 74 75 #include <net/if_arc.h> 76 #include <net/iso88025.h> 77 78 #define SIN(s) ((struct sockaddr_in *)s) 79 #define SDL(s) ((struct sockaddr_dl *)s) 80 81 SYSCTL_DECL(_net_link_ether); 82 SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, ""); 83 84 /* timer values */ 85 static int arpt_prune = (5*60*1); /* walk list every 5 minutes */ 86 static int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */ 87 static int arpt_down = 20; /* once declared down, don't send for 20 sec */ 88 89 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, prune_intvl, CTLFLAG_RW, 90 &arpt_prune, 0, ""); 91 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW, 92 &arpt_keep, 0, ""); 93 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, host_down_time, CTLFLAG_RW, 94 &arpt_down, 0, ""); 95 96 #define rt_expire rt_rmx.rmx_expire 97 98 struct llinfo_arp { 99 LIST_ENTRY(llinfo_arp) la_le; 100 struct rtentry *la_rt; 101 struct mbuf *la_hold; /* last packet until resolved/timeout */ 102 u_short la_preempt; /* countdown for pre-expiry arps */ 103 u_short la_asked; /* #times we QUERIED following expiration */ 104 }; 105 106 static LIST_HEAD(, llinfo_arp) llinfo_arp; 107 108 static int arp_inuse, arp_allocated, arpinit_done; 109 110 static int arp_maxtries = 5; 111 static int useloopback = 1; /* use loopback interface for local traffic */ 112 static int arp_proxyall = 0; 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_rtrequest (int, struct rtentry *, struct rt_addrinfo *); 122 static void arprequest (struct ifnet *, 123 struct in_addr *, struct in_addr *, u_char *); 124 static int arpintr(struct netmsg *); 125 static void arptfree (struct llinfo_arp *); 126 static void arptimer (void *); 127 static struct llinfo_arp 128 *arplookup (u_long, int, int); 129 #ifdef INET 130 static void in_arpinput (struct mbuf *); 131 #endif 132 133 static struct callout arptimer_ch; 134 135 /* 136 * Timeout routine. Age arp_tab entries periodically. 137 */ 138 /* ARGSUSED */ 139 static void 140 arptimer(ignored_arg) 141 void *ignored_arg; 142 { 143 int s = splnet(); 144 struct llinfo_arp *la, *nla; 145 146 LIST_FOREACH_MUTABLE(la, &llinfo_arp, la_le, nla) { 147 if (la->la_rt->rt_expire && la->la_rt->rt_expire <= time_second) 148 arptfree(la); /* might remove la from llinfo_arp! */ 149 } 150 callout_reset(&arptimer_ch, arpt_prune * hz, arptimer, NULL); 151 splx(s); 152 } 153 154 /* 155 * Parallel to llc_rtrequest. 156 */ 157 static void 158 arp_rtrequest(req, rt, info) 159 int req; 160 struct rtentry *rt; 161 struct rt_addrinfo *info; 162 { 163 struct sockaddr *gate = rt->rt_gateway; 164 struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo; 165 static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK}; 166 167 if (!arpinit_done) { 168 arpinit_done = 1; 169 callout_init(&arptimer_ch); 170 callout_reset(&arptimer_ch, hz, arptimer, NULL); 171 } 172 if (rt->rt_flags & RTF_GATEWAY) 173 return; 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, "arp_rtrequest: bad gateway value\n"); 208 break; 209 } 210 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 211 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 212 if (la != 0) 213 break; /* This happens on a route change */ 214 /* 215 * Case 2: This route may come from cloning, or a manual route 216 * add with a LL address. 217 */ 218 R_Malloc(la, struct llinfo_arp *, sizeof(*la)); 219 rt->rt_llinfo = (caddr_t)la; 220 if (la == 0) { 221 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); 222 break; 223 } 224 arp_inuse++, arp_allocated++; 225 bzero(la, sizeof(*la)); 226 la->la_rt = rt; 227 rt->rt_flags |= RTF_LLINFO; 228 LIST_INSERT_HEAD(&llinfo_arp, la, la_le); 229 230 #ifdef INET 231 /* 232 * This keeps the multicast addresses from showing up 233 * in `arp -a' listings as unresolved. It's not actually 234 * functional. Then the same for broadcast. 235 */ 236 if (IN_MULTICAST(ntohl(SIN(rt_key(rt))->sin_addr.s_addr)) 237 && rt->rt_ifp->if_type != IFT_ARCNET) { 238 ETHER_MAP_IP_MULTICAST(&SIN(rt_key(rt))->sin_addr, 239 LLADDR(SDL(gate))); 240 SDL(gate)->sdl_alen = 6; 241 rt->rt_expire = 0; 242 } 243 if (in_broadcast(SIN(rt_key(rt))->sin_addr, rt->rt_ifp)) { 244 memcpy(LLADDR(SDL(gate)), rt->rt_ifp->if_broadcastaddr, 245 rt->rt_ifp->if_addrlen); 246 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen; 247 rt->rt_expire = 0; 248 } 249 #endif 250 251 if (SIN(rt_key(rt))->sin_addr.s_addr == 252 (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) { 253 /* 254 * This test used to be 255 * if (loif.if_flags & IFF_UP) 256 * It allowed local traffic to be forced 257 * through the hardware by configuring the loopback down. 258 * However, it causes problems during network configuration 259 * for boards that can't receive packets they send. 260 * It is now necessary to clear "useloopback" and remove 261 * the route to force traffic out to the hardware. 262 */ 263 rt->rt_expire = 0; 264 bcopy(IF_LLADDR(rt->rt_ifp), LLADDR(SDL(gate)), 265 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen); 266 if (useloopback) 267 rt->rt_ifp = loif; 268 269 } 270 break; 271 272 case RTM_DELETE: 273 if (la == 0) 274 break; 275 arp_inuse--; 276 LIST_REMOVE(la, la_le); 277 rt->rt_llinfo = 0; 278 rt->rt_flags &= ~RTF_LLINFO; 279 if (la->la_hold) 280 m_freem(la->la_hold); 281 Free((caddr_t)la); 282 } 283 } 284 285 /* 286 * Broadcast an ARP request. Caller specifies: 287 * - arp header source ip address 288 * - arp header target ip address 289 * - arp header source ethernet address 290 */ 291 static void 292 arprequest(ifp, sip, tip, enaddr) 293 struct ifnet *ifp; 294 struct in_addr *sip, *tip; 295 u_char *enaddr; 296 { 297 struct mbuf *m; 298 struct ether_header *eh; 299 struct arc_header *arh; 300 struct arphdr *ah; 301 struct sockaddr sa; 302 static u_char llcx[] = { 0x82, 0x40, LLC_SNAP_LSAP, LLC_SNAP_LSAP, 303 LLC_UI, 0x00, 0x00, 0x00, 0x08, 0x06 }; 304 u_short ar_hrd; 305 306 if ((m = m_gethdr(MB_DONTWAIT, MT_DATA)) == NULL) 307 return; 308 m->m_pkthdr.rcvif = (struct ifnet *)0; 309 switch (ifp->if_type) { 310 case IFT_ARCNET: 311 ar_hrd = htons(ARPHRD_ARCNET); 312 313 m->m_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 314 m->m_pkthdr.len = m->m_len; 315 MH_ALIGN(m, m->m_len); 316 317 arh = (struct arc_header *)sa.sa_data; 318 arh->arc_dhost = ifp->if_broadcastaddr[0]; 319 arh->arc_type = ARCTYPE_ARP; 320 321 ah = mtod(m, struct arphdr *); 322 break; 323 324 case IFT_ISO88025: 325 ar_hrd = htons(ARPHRD_IEEE802); 326 327 m->m_len = sizeof(llcx) + 328 arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 329 m->m_pkthdr.len = m->m_len; 330 MH_ALIGN(m, m->m_len); 331 332 (void)memcpy(mtod(m, caddr_t), llcx, sizeof(llcx)); 333 memcpy(sa.sa_data, ifp->if_broadcastaddr, ifp->if_addrlen); 334 (void)memcpy(sa.sa_data + 6, enaddr, 6); 335 sa.sa_data[6] |= TR_RII; 336 sa.sa_data[12] = TR_AC; 337 sa.sa_data[13] = TR_LLC_FRAME; 338 339 ah = (struct arphdr *)(mtod(m, char *) + sizeof(llcx)); 340 break; 341 case IFT_FDDI: 342 case IFT_ETHER: 343 /* 344 * This may not be correct for types not explicitly 345 * listed, but this is our best guess 346 */ 347 default: 348 ar_hrd = htons(ARPHRD_ETHER); 349 350 m->m_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 351 m->m_pkthdr.len = m->m_len; 352 MH_ALIGN(m, m->m_len); 353 354 eh = (struct ether_header *)sa.sa_data; 355 /* if_output will not swap */ 356 eh->ether_type = htons(ETHERTYPE_ARP); 357 memcpy(eh->ether_dhost, ifp->if_broadcastaddr, ifp->if_addrlen); 358 359 ah = mtod(m, struct arphdr *); 360 break; 361 } 362 363 ah->ar_hrd = ar_hrd; 364 ah->ar_pro = htons(ETHERTYPE_IP); 365 ah->ar_hln = ifp->if_addrlen; /* hardware address length */ 366 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 367 ah->ar_op = htons(ARPOP_REQUEST); 368 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln); 369 memset(ar_tha(ah), 0, ah->ar_hln); 370 (void)memcpy(ar_spa(ah), sip, ah->ar_pln); 371 (void)memcpy(ar_tpa(ah), tip, ah->ar_pln); 372 373 sa.sa_family = AF_UNSPEC; 374 sa.sa_len = sizeof(sa); 375 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 376 } 377 378 /* 379 * Resolve an IP address into an ethernet address. If success, 380 * desten is filled in. If there is no entry in arptab, 381 * set one up and broadcast a request for the IP address. 382 * Hold onto this mbuf and resend it once the address 383 * is finally resolved. A return value of 1 indicates 384 * that desten has been filled in and the packet should be sent 385 * normally; a 0 return indicates that the packet has been 386 * taken over here, either now or for later transmission. 387 */ 388 int 389 arpresolve(ifp, rt, m, dst, desten, rt0) 390 struct ifnet *ifp; 391 struct rtentry *rt; 392 struct mbuf *m; 393 struct sockaddr *dst; 394 u_char *desten; 395 struct rtentry *rt0; 396 { 397 struct llinfo_arp *la = 0; 398 struct sockaddr_dl *sdl; 399 400 if (m->m_flags & M_BCAST) { /* broadcast */ 401 memcpy(desten, ifp->if_broadcastaddr, ifp->if_addrlen); 402 return (1); 403 } 404 if (m->m_flags & M_MCAST && ifp->if_type != IFT_ARCNET) {/* multicast */ 405 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); 406 return(1); 407 } 408 if (rt) 409 la = (struct llinfo_arp *)rt->rt_llinfo; 410 if (la == 0) { 411 la = arplookup(SIN(dst)->sin_addr.s_addr, 1, 0); 412 if (la) 413 rt = la->la_rt; 414 } 415 if (la == 0 || rt == 0) { 416 log(LOG_DEBUG, "arpresolve: can't allocate llinfo for %s%s%s\n", 417 inet_ntoa(SIN(dst)->sin_addr), la ? "la" : "", 418 rt ? "rt" : ""); 419 m_freem(m); 420 return (0); 421 } 422 sdl = SDL(rt->rt_gateway); 423 /* 424 * Check the address family and length is valid, the address 425 * is resolved; otherwise, try to resolve. 426 */ 427 if ((rt->rt_expire == 0 || rt->rt_expire > time_second) && 428 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 429 /* 430 * If entry has an expiry time and it is approaching, 431 * see if we need to send an ARP request within this 432 * arpt_down interval. 433 */ 434 if ((rt->rt_expire != 0) && 435 (time_second + la->la_preempt > rt->rt_expire)) { 436 arprequest(ifp, 437 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 438 &SIN(dst)->sin_addr, 439 IF_LLADDR(ifp)); 440 la->la_preempt--; 441 } 442 443 bcopy(LLADDR(sdl), desten, sdl->sdl_alen); 444 return 1; 445 } 446 /* 447 * If ARP is disabled on this interface, stop. 448 * XXX 449 * Probably should not allocate empty llinfo struct if we are 450 * not going to be sending out an arp request. 451 */ 452 if (ifp->if_flags & IFF_NOARP) { 453 m_freem(m); 454 return (0); 455 } 456 /* 457 * There is an arptab entry, but no ethernet address 458 * response yet. Replace the held mbuf with this 459 * latest one. 460 */ 461 if (la->la_hold) 462 m_freem(la->la_hold); 463 la->la_hold = m; 464 if (rt->rt_expire || ((rt->rt_flags & RTF_STATIC) && !sdl->sdl_alen)) { 465 rt->rt_flags &= ~RTF_REJECT; 466 if (la->la_asked == 0 || rt->rt_expire != time_second) { 467 rt->rt_expire = time_second; 468 if (la->la_asked++ < arp_maxtries) { 469 arprequest(ifp, 470 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 471 &SIN(dst)->sin_addr, 472 IF_LLADDR(ifp)); 473 } else { 474 rt->rt_flags |= RTF_REJECT; 475 rt->rt_expire += arpt_down; 476 la->la_asked = 0; 477 la->la_preempt = arp_maxtries; 478 } 479 480 } 481 } 482 return (0); 483 } 484 485 /* 486 * Common length and type checks are done here, 487 * then the protocol-specific routine is called. 488 */ 489 static int 490 arpintr(struct netmsg *msg) 491 { 492 struct mbuf *m = ((struct netmsg_packet *)msg)->nm_packet; 493 struct arphdr *ar; 494 u_short ar_hrd; 495 496 if (m->m_len < sizeof(struct arphdr) && 497 ((m = m_pullup(m, sizeof(struct arphdr))) == NULL)) { 498 log(LOG_ERR, "arp: runt packet -- m_pullup failed\n"); 499 goto out2; 500 } 501 ar = mtod(m, struct arphdr *); 502 503 ar_hrd = ntohs(ar->ar_hrd); 504 if (ar_hrd != ARPHRD_ETHER && 505 ar_hrd != ARPHRD_IEEE802 && 506 ar_hrd != ARPHRD_ARCNET) { 507 log(LOG_ERR, 508 "arp: unknown hardware address format (0x%2D)\n", 509 (unsigned char *)&ar->ar_hrd, ""); 510 goto out1; 511 } 512 513 if (m->m_pkthdr.len < arphdr_len(ar) && 514 (m = m_pullup(m, arphdr_len(ar))) == NULL) { 515 log(LOG_ERR, "arp: runt packet\n"); 516 goto out1; 517 } 518 519 switch (ntohs(ar->ar_pro)) { 520 #ifdef INET 521 case ETHERTYPE_IP: 522 in_arpinput(m); 523 goto out2; 524 #endif 525 } 526 out1: 527 m_freem(m); 528 out2: 529 lwkt_replymsg(&msg->nm_lmsg, 0); 530 return(EASYNC); 531 } 532 533 #ifdef INET 534 /* 535 * ARP for Internet protocols on 10 Mb/s Ethernet. 536 * Algorithm is that given in RFC 826. 537 * In addition, a sanity check is performed on the sender 538 * protocol address, to catch impersonators. 539 * We no longer handle negotiations for use of trailer protocol: 540 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 541 * along with IP replies if we wanted trailers sent to us, 542 * and also sent them in response to IP replies. 543 * This allowed either end to announce the desire to receive 544 * trailer packets. 545 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 546 * but formerly didn't normally send requests. 547 */ 548 static int log_arp_wrong_iface = 1; 549 550 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW, 551 &log_arp_wrong_iface, 0, 552 "log arp packets arriving on the wrong interface"); 553 554 static void 555 in_arpinput(m) 556 struct mbuf *m; 557 { 558 struct arphdr *ah; 559 struct ifnet *ifp = m->m_pkthdr.rcvif; 560 struct ether_header *eh; 561 struct arc_header *arh; 562 struct iso88025_header *th = (struct iso88025_header *)0; 563 struct iso88025_sockaddr_dl_data *trld; 564 struct llinfo_arp *la = 0; 565 struct rtentry *rt; 566 struct ifaddr *ifa; 567 struct in_ifaddr *ia; 568 struct sockaddr_dl *sdl; 569 struct sockaddr sa; 570 struct in_addr isaddr, itaddr, myaddr; 571 int op, rif_len; 572 int req_len; 573 574 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 575 if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) { 576 log(LOG_ERR, "in_arp: runt packet -- m_pullup failed\n"); 577 return; 578 } 579 580 ah = mtod(m, struct arphdr *); 581 op = ntohs(ah->ar_op); 582 (void)memcpy(&isaddr, ar_spa(ah), sizeof (isaddr)); 583 (void)memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr)); 584 #ifdef BRIDGE 585 #define BRIDGE_TEST (do_bridge) 586 #else 587 #define BRIDGE_TEST (0) /* cc will optimise the test away */ 588 #endif 589 /* 590 * For a bridge, we want to check the address irrespective 591 * of the receive interface. (This will change slightly 592 * when we have clusters of interfaces). 593 */ 594 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) 595 if ((BRIDGE_TEST || (ia->ia_ifp == ifp)) && 596 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) 597 goto match; 598 LIST_FOREACH(ia, INADDR_HASH(isaddr.s_addr), ia_hash) 599 if ((BRIDGE_TEST || (ia->ia_ifp == ifp)) && 600 isaddr.s_addr == ia->ia_addr.sin_addr.s_addr) 601 goto match; 602 /* 603 * No match, use the first inet address on the receive interface 604 * as a dummy address for the rest of the function. 605 */ 606 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) 607 if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_INET) { 608 ia = ifatoia(ifa); 609 goto match; 610 } 611 /* 612 * If bridging, fall back to using any inet address. 613 * This is probably incorrect, the right way being try to match 614 * addresses for interfaces in the same cluster, so if we 615 * get here we should always drop the packet. 616 */ 617 if (!BRIDGE_TEST || 618 (ia = TAILQ_FIRST(&in_ifaddrhead)) == NULL) { 619 m_freem(m); 620 return; 621 } 622 match: 623 myaddr = ia->ia_addr.sin_addr; 624 if (!bcmp(ar_sha(ah), IF_LLADDR(ifp), ifp->if_addrlen)) { 625 m_freem(m); /* it's from me, ignore it. */ 626 return; 627 } 628 if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) { 629 log(LOG_ERR, 630 "arp: link address is broadcast for IP address %s!\n", 631 inet_ntoa(isaddr)); 632 m_freem(m); 633 return; 634 } 635 if (isaddr.s_addr == myaddr.s_addr && myaddr.s_addr != 0) { 636 log(LOG_ERR, 637 "arp: %*D is using my IP address %s!\n", 638 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 639 inet_ntoa(isaddr)); 640 itaddr = myaddr; 641 goto reply; 642 } 643 la = arplookup(isaddr.s_addr, itaddr.s_addr == myaddr.s_addr, 0); 644 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { 645 /* the following is not an error when doing bridging */ 646 if (!BRIDGE_TEST && rt->rt_ifp != ifp) { 647 if (log_arp_wrong_iface) 648 log(LOG_ERR, "arp: %s is on %s but got reply from %*D on %s\n", 649 inet_ntoa(isaddr), 650 rt->rt_ifp->if_xname, 651 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 652 ifp->if_xname); 653 goto reply; 654 } 655 if (sdl->sdl_alen && 656 bcmp(ar_sha(ah), LLADDR(sdl), sdl->sdl_alen)) { 657 if (rt->rt_expire) 658 log(LOG_INFO, "arp: %s moved from %*D to %*D on %s\n", 659 inet_ntoa(isaddr), 660 ifp->if_addrlen, (u_char *)LLADDR(sdl), ":", 661 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 662 ifp->if_xname); 663 else { 664 log(LOG_ERR, 665 "arp: %*D attempts to modify permanent entry for %s on %s\n", 666 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 667 inet_ntoa(isaddr), ifp->if_xname); 668 goto reply; 669 } 670 } 671 /* 672 * sanity check for the address length. 673 * XXX this does not work for protocols with variable address 674 * length. -is 675 */ 676 if (sdl->sdl_alen && 677 sdl->sdl_alen != ah->ar_hln) { 678 log(LOG_WARNING, 679 "arp from %*D: new addr len %d, was %d", 680 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 681 ah->ar_hln, sdl->sdl_alen); 682 } 683 if (ifp->if_addrlen != ah->ar_hln) { 684 log(LOG_WARNING, 685 "arp from %*D: addr len: new %d, i/f %d (ignored)", 686 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 687 ah->ar_hln, ifp->if_addrlen); 688 goto reply; 689 } 690 (void)memcpy(LLADDR(sdl), ar_sha(ah), 691 sdl->sdl_alen = ah->ar_hln); 692 /* 693 * If we receive an arp from a token-ring station over 694 * a token-ring nic then try to save the source 695 * routing info. 696 */ 697 if (ifp->if_type == IFT_ISO88025) { 698 th = (struct iso88025_header *)m->m_pkthdr.header; 699 trld = SDL_ISO88025(sdl); 700 rif_len = TR_RCF_RIFLEN(th->rcf); 701 if ((th->iso88025_shost[0] & TR_RII) && 702 (rif_len > 2)) { 703 trld->trld_rcf = th->rcf; 704 trld->trld_rcf ^= htons(TR_RCF_DIR); 705 memcpy(trld->trld_route, th->rd, rif_len - 2); 706 trld->trld_rcf &= ~htons(TR_RCF_BCST_MASK); 707 /* 708 * Set up source routing information for 709 * reply packet (XXX) 710 */ 711 m->m_data -= rif_len; 712 m->m_len += rif_len; 713 m->m_pkthdr.len += rif_len; 714 } else { 715 th->iso88025_shost[0] &= ~TR_RII; 716 trld->trld_rcf = 0; 717 } 718 m->m_data -= 8; 719 m->m_len += 8; 720 m->m_pkthdr.len += 8; 721 th->rcf = trld->trld_rcf; 722 } 723 if (rt->rt_expire) 724 rt->rt_expire = time_second + arpt_keep; 725 rt->rt_flags &= ~RTF_REJECT; 726 la->la_asked = 0; 727 la->la_preempt = arp_maxtries; 728 if (la->la_hold) { 729 (*ifp->if_output)(ifp, la->la_hold, 730 rt_key(rt), rt); 731 la->la_hold = 0; 732 } 733 } 734 reply: 735 if (op != ARPOP_REQUEST) { 736 m_freem(m); 737 return; 738 } 739 if (itaddr.s_addr == myaddr.s_addr) { 740 /* I am the target */ 741 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 742 (void)memcpy(ar_sha(ah), IF_LLADDR(ifp), ah->ar_hln); 743 } else { 744 la = arplookup(itaddr.s_addr, 0, SIN_PROXY); 745 if (la == NULL) { 746 struct sockaddr_in sin; 747 748 if (!arp_proxyall) { 749 m_freem(m); 750 return; 751 } 752 753 bzero(&sin, sizeof sin); 754 sin.sin_family = AF_INET; 755 sin.sin_len = sizeof sin; 756 sin.sin_addr = itaddr; 757 758 rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL); 759 if (!rt) { 760 m_freem(m); 761 return; 762 } 763 /* 764 * Don't send proxies for nodes on the same interface 765 * as this one came out of, or we'll get into a fight 766 * over who claims what Ether address. 767 */ 768 if (rt->rt_ifp == ifp) { 769 rtfree(rt); 770 m_freem(m); 771 return; 772 } 773 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 774 (void)memcpy(ar_sha(ah), IF_LLADDR(ifp), ah->ar_hln); 775 rtfree(rt); 776 #ifdef DEBUG_PROXY 777 printf("arp: proxying for %s\n", 778 inet_ntoa(itaddr)); 779 #endif 780 } else { 781 rt = la->la_rt; 782 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 783 sdl = SDL(rt->rt_gateway); 784 (void)memcpy(ar_sha(ah), LLADDR(sdl), ah->ar_hln); 785 } 786 } 787 788 (void)memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln); 789 (void)memcpy(ar_spa(ah), &itaddr, ah->ar_pln); 790 ah->ar_op = htons(ARPOP_REPLY); 791 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 792 switch (ifp->if_type) { 793 case IFT_ARCNET: 794 arh = (struct arc_header *)sa.sa_data; 795 arh->arc_dhost = *ar_tha(ah); 796 arh->arc_type = ARCTYPE_ARP; 797 break; 798 799 case IFT_ISO88025: 800 /* Re-arrange the source/dest address */ 801 memcpy(th->iso88025_dhost, th->iso88025_shost, 802 sizeof(th->iso88025_dhost)); 803 memcpy(th->iso88025_shost, IF_LLADDR(ifp), 804 sizeof(th->iso88025_shost)); 805 /* Set the source routing bit if neccesary */ 806 if (th->iso88025_dhost[0] & TR_RII) { 807 th->iso88025_dhost[0] &= ~TR_RII; 808 if (TR_RCF_RIFLEN(th->rcf) > 2) 809 th->iso88025_shost[0] |= TR_RII; 810 } 811 /* Copy the addresses, ac and fc into sa_data */ 812 memcpy(sa.sa_data, th->iso88025_dhost, 813 sizeof(th->iso88025_dhost) * 2); 814 sa.sa_data[(sizeof(th->iso88025_dhost) * 2)] = TR_AC; 815 sa.sa_data[(sizeof(th->iso88025_dhost) * 2) + 1] = TR_LLC_FRAME; 816 break; 817 case IFT_ETHER: 818 case IFT_FDDI: 819 /* 820 * May not be correct for types not explictly 821 * listed, but it is our best guess. 822 */ 823 default: 824 eh = (struct ether_header *)sa.sa_data; 825 (void)memcpy(eh->ether_dhost, ar_tha(ah), 826 sizeof(eh->ether_dhost)); 827 eh->ether_type = htons(ETHERTYPE_ARP); 828 break; 829 } 830 sa.sa_family = AF_UNSPEC; 831 sa.sa_len = sizeof(sa); 832 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 833 return; 834 } 835 #endif 836 837 /* 838 * Free an arp entry. If the arp entry is actively referenced or represents 839 * a static entry we only clear it back to an unresolved state, otherwise 840 * we destroy the entry entirely. 841 * 842 * Note that static entries are created when route add ... -interface is used 843 * to create an interface route to a (direct) destination. 844 */ 845 static void 846 arptfree(la) 847 struct llinfo_arp *la; 848 { 849 struct rtentry *rt = la->la_rt; 850 struct sockaddr_dl *sdl; 851 if (rt == NULL) 852 panic("arptfree"); 853 sdl = SDL(rt->rt_gateway); 854 if (sdl && ((rt->rt_refcnt > 0 && sdl->sdl_family == AF_LINK) || 855 (rt->rt_flags & RTF_STATIC))) { 856 sdl->sdl_alen = 0; 857 la->la_preempt = la->la_asked = 0; 858 rt->rt_flags &= ~RTF_REJECT; 859 return; 860 } 861 rtrequest(RTM_DELETE, rt_key(rt), (struct sockaddr *)0, rt_mask(rt), 862 0, (struct rtentry **)0); 863 } 864 /* 865 * Lookup or enter a new address in arptab. 866 */ 867 static struct llinfo_arp * 868 arplookup(addr, create, proxy) 869 u_long addr; 870 int create, proxy; 871 { 872 struct rtentry *rt; 873 static struct sockaddr_inarp sin = {sizeof(sin), AF_INET }; 874 const char *why = 0; 875 876 sin.sin_addr.s_addr = addr; 877 sin.sin_other = proxy ? SIN_PROXY : 0; 878 rt = rtalloc1((struct sockaddr *)&sin, create, 0UL); 879 if (rt == 0) 880 return (0); 881 rt->rt_refcnt--; 882 883 if (rt->rt_flags & RTF_GATEWAY) 884 why = "host is not on local network"; 885 else if ((rt->rt_flags & RTF_LLINFO) == 0) 886 why = "could not allocate llinfo"; 887 else if (rt->rt_gateway->sa_family != AF_LINK) 888 why = "gateway route is not ours"; 889 890 if (why) { 891 if (create) { 892 log(LOG_DEBUG, "arplookup %s failed: %s\n", 893 inet_ntoa(sin.sin_addr), why); 894 } 895 896 /* if there are no references to this route, purge it */ 897 if (rt->rt_refcnt <= 0 && 898 (rt->rt_flags & RTF_WASCLONED) == RTF_WASCLONED) { 899 rtrequest(RTM_DELETE, 900 (struct sockaddr *)rt_key(rt), rt->rt_gateway, 901 rt_mask(rt), rt->rt_flags, 0); 902 } 903 return (0); 904 } 905 return ((struct llinfo_arp *)rt->rt_llinfo); 906 } 907 908 void 909 arp_ifinit(ifp, ifa) 910 struct ifnet *ifp; 911 struct ifaddr *ifa; 912 { 913 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY) 914 arprequest(ifp, &IA_SIN(ifa)->sin_addr, 915 &IA_SIN(ifa)->sin_addr, IF_LLADDR(ifp)); 916 ifa->ifa_rtrequest = arp_rtrequest; 917 ifa->ifa_flags |= RTF_CLONING; 918 } 919 920 static void 921 arp_init(void) 922 { 923 LIST_INIT(&llinfo_arp); 924 netisr_register(NETISR_ARP, cpu0_portfn, arpintr); 925 } 926 927 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0); 928