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 1.9 2004/01/06 03:17:27 dillon 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 <net/if.h> 58 #include <net/if_dl.h> 59 #include <net/if_types.h> 60 #include <net/route.h> 61 #include <net/netisr.h> 62 #include <net/if_llc.h> 63 #ifdef BRIDGE 64 #include <net/ethernet.h> 65 #include <net/bridge/bridge.h> 66 #endif 67 68 #include <netinet/in.h> 69 #include <netinet/in_var.h> 70 #include <netinet/if_ether.h> 71 72 #include <net/if_arc.h> 73 #include <net/iso88025.h> 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; /* #times we QUERIED before entry expiration */ 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 int arp_inuse, arp_allocated, arpinit_done; 107 108 static int arp_maxtries = 5; 109 static int useloopback = 1; /* use loopback interface for local traffic */ 110 static int arp_proxyall = 0; 111 112 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW, 113 &arp_maxtries, 0, ""); 114 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW, 115 &useloopback, 0, ""); 116 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW, 117 &arp_proxyall, 0, ""); 118 119 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 u_char arcbroadcastaddr = 0; 132 133 #define IF_BCASTADDR(ifp) \ 134 ((ifp)->if_type == IFT_ARCNET ? \ 135 &arcbroadcastaddr : etherbroadcastaddr) 136 137 /* 138 * Timeout routine. Age arp_tab entries periodically. 139 */ 140 /* ARGSUSED */ 141 static void 142 arptimer(ignored_arg) 143 void *ignored_arg; 144 { 145 int s = splnet(); 146 struct llinfo_arp *la = LIST_FIRST(&llinfo_arp); 147 struct llinfo_arp *ola; 148 149 timeout(arptimer, (caddr_t)0, arpt_prune * hz); 150 while ((ola = la) != 0) { 151 struct rtentry *rt = la->la_rt; 152 la = LIST_NEXT(la, la_le); 153 if (rt->rt_expire && rt->rt_expire <= time_second) 154 arptfree(ola); /* timer has expired, clear */ 155 } 156 splx(s); 157 } 158 159 /* 160 * Parallel to llc_rtrequest. 161 */ 162 static void 163 arp_rtrequest(req, rt, info) 164 int req; 165 struct rtentry *rt; 166 struct rt_addrinfo *info; 167 { 168 struct sockaddr *gate = rt->rt_gateway; 169 struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo; 170 static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK}; 171 172 if (!arpinit_done) { 173 arpinit_done = 1; 174 timeout(arptimer, (caddr_t)0, hz); 175 } 176 if (rt->rt_flags & RTF_GATEWAY) 177 return; 178 switch (req) { 179 180 case RTM_ADD: 181 /* 182 * XXX: If this is a manually added route to interface 183 * such as older version of routed or gated might provide, 184 * restore cloning bit. 185 */ 186 if ((rt->rt_flags & RTF_HOST) == 0 && 187 SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff) 188 rt->rt_flags |= RTF_CLONING; 189 if (rt->rt_flags & RTF_CLONING) { 190 /* 191 * Case 1: This route should come from a route to iface. 192 */ 193 rt_setgate(rt, rt_key(rt), 194 (struct sockaddr *)&null_sdl); 195 gate = rt->rt_gateway; 196 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 197 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 198 rt->rt_expire = time_second; 199 break; 200 } 201 /* Announce a new entry if requested. */ 202 if (rt->rt_flags & RTF_ANNOUNCE) 203 arprequest(rt->rt_ifp, 204 &SIN(rt_key(rt))->sin_addr, 205 &SIN(rt_key(rt))->sin_addr, 206 (u_char *)LLADDR(SDL(gate))); 207 /*FALLTHROUGH*/ 208 case RTM_RESOLVE: 209 if (gate->sa_family != AF_LINK || 210 gate->sa_len < sizeof(null_sdl)) { 211 log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n"); 212 break; 213 } 214 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 215 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 216 if (la != 0) 217 break; /* This happens on a route change */ 218 /* 219 * Case 2: This route may come from cloning, or a manual route 220 * add with a LL address. 221 */ 222 R_Malloc(la, struct llinfo_arp *, sizeof(*la)); 223 rt->rt_llinfo = (caddr_t)la; 224 if (la == 0) { 225 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); 226 break; 227 } 228 arp_inuse++, arp_allocated++; 229 Bzero(la, sizeof(*la)); 230 la->la_rt = rt; 231 rt->rt_flags |= RTF_LLINFO; 232 LIST_INSERT_HEAD(&llinfo_arp, la, la_le); 233 234 #ifdef INET 235 /* 236 * This keeps the multicast addresses from showing up 237 * in `arp -a' listings as unresolved. It's not actually 238 * functional. Then the same for broadcast. 239 */ 240 if (IN_MULTICAST(ntohl(SIN(rt_key(rt))->sin_addr.s_addr)) 241 && rt->rt_ifp->if_type != IFT_ARCNET) { 242 ETHER_MAP_IP_MULTICAST(&SIN(rt_key(rt))->sin_addr, 243 LLADDR(SDL(gate))); 244 SDL(gate)->sdl_alen = 6; 245 rt->rt_expire = 0; 246 } 247 if (in_broadcast(SIN(rt_key(rt))->sin_addr, rt->rt_ifp)) { 248 memcpy(LLADDR(SDL(gate)), IF_BCASTADDR(rt->rt_ifp), 249 rt->rt_ifp->if_addrlen); 250 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen; 251 rt->rt_expire = 0; 252 } 253 #endif 254 255 if (SIN(rt_key(rt))->sin_addr.s_addr == 256 (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) { 257 /* 258 * This test used to be 259 * if (loif.if_flags & IFF_UP) 260 * It allowed local traffic to be forced 261 * through the hardware by configuring the loopback down. 262 * However, it causes problems during network configuration 263 * for boards that can't receive packets they send. 264 * It is now necessary to clear "useloopback" and remove 265 * the route to force traffic out to the hardware. 266 */ 267 rt->rt_expire = 0; 268 Bcopy(IF_LLADDR(rt->rt_ifp), LLADDR(SDL(gate)), 269 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen); 270 if (useloopback) 271 rt->rt_ifp = loif; 272 273 } 274 break; 275 276 case RTM_DELETE: 277 if (la == 0) 278 break; 279 arp_inuse--; 280 LIST_REMOVE(la, la_le); 281 rt->rt_llinfo = 0; 282 rt->rt_flags &= ~RTF_LLINFO; 283 if (la->la_hold) 284 m_freem(la->la_hold); 285 Free((caddr_t)la); 286 } 287 } 288 289 /* 290 * Broadcast an ARP request. Caller specifies: 291 * - arp header source ip address 292 * - arp header target ip address 293 * - arp header source ethernet address 294 */ 295 static void 296 arprequest(ifp, sip, tip, enaddr) 297 struct ifnet *ifp; 298 struct in_addr *sip, *tip; 299 u_char *enaddr; 300 { 301 struct mbuf *m; 302 struct ether_header *eh; 303 struct arc_header *arh; 304 struct arphdr *ah; 305 struct sockaddr sa; 306 static u_char llcx[] = { 0x82, 0x40, LLC_SNAP_LSAP, LLC_SNAP_LSAP, 307 LLC_UI, 0x00, 0x00, 0x00, 0x08, 0x06 }; 308 u_short ar_hrd; 309 310 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 311 return; 312 m->m_pkthdr.rcvif = (struct ifnet *)0; 313 switch (ifp->if_type) { 314 case IFT_ARCNET: 315 ar_hrd = htons(ARPHRD_ARCNET); 316 317 m->m_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 318 m->m_pkthdr.len = m->m_len; 319 MH_ALIGN(m, m->m_len); 320 321 arh = (struct arc_header *)sa.sa_data; 322 arh->arc_dhost = arcbroadcastaddr; 323 arh->arc_type = ARCTYPE_ARP; 324 325 ah = mtod(m, struct arphdr *); 326 break; 327 328 case IFT_ISO88025: 329 ar_hrd = htons(ARPHRD_IEEE802); 330 331 m->m_len = sizeof(llcx) + 332 arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 333 m->m_pkthdr.len = m->m_len; 334 MH_ALIGN(m, m->m_len); 335 336 (void)memcpy(mtod(m, caddr_t), llcx, sizeof(llcx)); 337 (void)memcpy(sa.sa_data, etherbroadcastaddr, 6); 338 (void)memcpy(sa.sa_data + 6, enaddr, 6); 339 sa.sa_data[6] |= TR_RII; 340 sa.sa_data[12] = TR_AC; 341 sa.sa_data[13] = TR_LLC_FRAME; 342 343 ah = (struct arphdr *)(mtod(m, char *) + sizeof(llcx)); 344 break; 345 case IFT_FDDI: 346 case IFT_ETHER: 347 /* 348 * This may not be correct for types not explicitly 349 * listed, but this is our best guess 350 */ 351 default: 352 ar_hrd = htons(ARPHRD_ETHER); 353 354 m->m_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 355 m->m_pkthdr.len = m->m_len; 356 MH_ALIGN(m, m->m_len); 357 358 eh = (struct ether_header *)sa.sa_data; 359 /* if_output will not swap */ 360 eh->ether_type = htons(ETHERTYPE_ARP); 361 (void)memcpy(eh->ether_dhost, etherbroadcastaddr, 362 sizeof(eh->ether_dhost)); 363 364 ah = mtod(m, struct arphdr *); 365 break; 366 } 367 368 ah->ar_hrd = ar_hrd; 369 ah->ar_pro = htons(ETHERTYPE_IP); 370 ah->ar_hln = ifp->if_addrlen; /* hardware address length */ 371 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 372 ah->ar_op = htons(ARPOP_REQUEST); 373 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln); 374 memset(ar_tha(ah), 0, ah->ar_hln); 375 (void)memcpy(ar_spa(ah), sip, ah->ar_pln); 376 (void)memcpy(ar_tpa(ah), tip, ah->ar_pln); 377 378 sa.sa_family = AF_UNSPEC; 379 sa.sa_len = sizeof(sa); 380 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 381 } 382 383 /* 384 * Resolve an IP address into an ethernet address. If success, 385 * desten is filled in. If there is no entry in arptab, 386 * set one up and broadcast a request for the IP address. 387 * Hold onto this mbuf and resend it once the address 388 * is finally resolved. A return value of 1 indicates 389 * that desten has been filled in and the packet should be sent 390 * normally; a 0 return indicates that the packet has been 391 * taken over here, either now or for later transmission. 392 */ 393 int 394 arpresolve(ifp, rt, m, dst, desten, rt0) 395 struct ifnet *ifp; 396 struct rtentry *rt; 397 struct mbuf *m; 398 struct sockaddr *dst; 399 u_char *desten; 400 struct rtentry *rt0; 401 { 402 struct llinfo_arp *la = 0; 403 struct sockaddr_dl *sdl; 404 405 if (m->m_flags & M_BCAST) { /* broadcast */ 406 (void)memcpy(desten, IF_BCASTADDR(ifp), ifp->if_addrlen); 407 return (1); 408 } 409 if (m->m_flags & M_MCAST && ifp->if_type != IFT_ARCNET) {/* multicast */ 410 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); 411 return(1); 412 } 413 if (rt) 414 la = (struct llinfo_arp *)rt->rt_llinfo; 415 if (la == 0) { 416 la = arplookup(SIN(dst)->sin_addr.s_addr, 1, 0); 417 if (la) 418 rt = la->la_rt; 419 } 420 if (la == 0 || rt == 0) { 421 log(LOG_DEBUG, "arpresolve: can't allocate llinfo for %s%s%s\n", 422 inet_ntoa(SIN(dst)->sin_addr), la ? "la" : "", 423 rt ? "rt" : ""); 424 m_freem(m); 425 return (0); 426 } 427 sdl = SDL(rt->rt_gateway); 428 /* 429 * Check the address family and length is valid, the address 430 * is resolved; otherwise, try to resolve. 431 */ 432 if ((rt->rt_expire == 0 || rt->rt_expire > time_second) && 433 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 434 /* 435 * If entry has an expiry time and it is approaching, 436 * see if we need to send an ARP request within this 437 * arpt_down interval. 438 */ 439 if ((rt->rt_expire != 0) && 440 (time_second + (arp_maxtries - la->la_preempt) * arpt_down 441 > rt->rt_expire)) { 442 arprequest(ifp, 443 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 444 &SIN(dst)->sin_addr, 445 IF_LLADDR(ifp)); 446 la->la_preempt++; 447 } 448 449 bcopy(LLADDR(sdl), desten, sdl->sdl_alen); 450 return 1; 451 } 452 /* 453 * If ARP is disabled on this interface, stop. 454 * XXX 455 * Probably should not allocate empty llinfo struct if we are 456 * not going to be sending out an arp request. 457 */ 458 if (ifp->if_flags & IFF_NOARP) { 459 m_freem(m); 460 return (0); 461 } 462 /* 463 * There is an arptab entry, but no ethernet address 464 * response yet. Replace the held mbuf with this 465 * latest one. 466 */ 467 if (la->la_hold) 468 m_freem(la->la_hold); 469 la->la_hold = m; 470 if (rt->rt_expire) { 471 rt->rt_flags &= ~RTF_REJECT; 472 if (la->la_asked == 0 || rt->rt_expire != time_second) { 473 rt->rt_expire = time_second; 474 if (la->la_asked++ < arp_maxtries) { 475 arprequest(ifp, 476 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 477 &SIN(dst)->sin_addr, 478 IF_LLADDR(ifp)); 479 } else { 480 rt->rt_flags |= RTF_REJECT; 481 rt->rt_expire += arpt_down; 482 la->la_preempt = la->la_asked = 0; 483 } 484 485 } 486 } 487 return (0); 488 } 489 490 /* 491 * Common length and type checks are done here, 492 * then the protocol-specific routine is called. 493 */ 494 static void 495 arpintr(struct mbuf *m) 496 { 497 struct arphdr *ar; 498 u_short ar_hrd; 499 500 if (m->m_len < sizeof(struct arphdr) && 501 ((m = m_pullup(m, sizeof(struct arphdr))) == NULL)) { 502 log(LOG_ERR, "arp: runt packet -- m_pullup failed\n"); 503 return; 504 } 505 ar = mtod(m, struct arphdr *); 506 507 ar_hrd = ntohs(ar->ar_hrd); 508 if (ar_hrd != ARPHRD_ETHER && 509 ar_hrd != ARPHRD_IEEE802 && 510 ar_hrd != ARPHRD_ARCNET) { 511 log(LOG_ERR, 512 "arp: unknown hardware address format (0x%2D)\n", 513 (unsigned char *)&ar->ar_hrd, ""); 514 m_freem(m); 515 return; 516 } 517 518 if (m->m_pkthdr.len < arphdr_len(ar) && 519 (m = m_pullup(m, arphdr_len(ar))) == NULL) { 520 log(LOG_ERR, "arp: runt packet\n"); 521 m_freem(m); 522 return; 523 } 524 525 switch (ntohs(ar->ar_pro)) { 526 #ifdef INET 527 case ETHERTYPE_IP: 528 in_arpinput(m); 529 return; 530 #endif 531 } 532 m_freem(m); 533 } 534 535 #ifdef INET 536 /* 537 * ARP for Internet protocols on 10 Mb/s Ethernet. 538 * Algorithm is that given in RFC 826. 539 * In addition, a sanity check is performed on the sender 540 * protocol address, to catch impersonators. 541 * We no longer handle negotiations for use of trailer protocol: 542 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 543 * along with IP replies if we wanted trailers sent to us, 544 * and also sent them in response to IP replies. 545 * This allowed either end to announce the desire to receive 546 * trailer packets. 547 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 548 * but formerly didn't normally send requests. 549 */ 550 static int log_arp_wrong_iface = 1; 551 552 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW, 553 &log_arp_wrong_iface, 0, 554 "log arp packets arriving on the wrong interface"); 555 556 static void 557 in_arpinput(m) 558 struct mbuf *m; 559 { 560 struct arphdr *ah; 561 struct ifnet *ifp = m->m_pkthdr.rcvif; 562 struct ether_header *eh; 563 struct arc_header *arh; 564 struct iso88025_header *th = (struct iso88025_header *)0; 565 struct iso88025_sockaddr_dl_data *trld; 566 struct llinfo_arp *la = 0; 567 struct rtentry *rt; 568 struct ifaddr *ifa; 569 struct in_ifaddr *ia; 570 struct sockaddr_dl *sdl; 571 struct sockaddr sa; 572 struct in_addr isaddr, itaddr, myaddr; 573 int op, rif_len; 574 int req_len; 575 576 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 577 if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) { 578 log(LOG_ERR, "in_arp: runt packet -- m_pullup failed\n"); 579 return; 580 } 581 582 ah = mtod(m, struct arphdr *); 583 op = ntohs(ah->ar_op); 584 (void)memcpy(&isaddr, ar_spa(ah), sizeof (isaddr)); 585 (void)memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr)); 586 #ifdef BRIDGE 587 #define BRIDGE_TEST (do_bridge) 588 #else 589 #define BRIDGE_TEST (0) /* cc will optimise the test away */ 590 #endif 591 /* 592 * For a bridge, we want to check the address irrespective 593 * of the receive interface. (This will change slightly 594 * when we have clusters of interfaces). 595 */ 596 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) 597 if ((BRIDGE_TEST || (ia->ia_ifp == ifp)) && 598 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) 599 goto match; 600 LIST_FOREACH(ia, INADDR_HASH(isaddr.s_addr), ia_hash) 601 if ((BRIDGE_TEST || (ia->ia_ifp == ifp)) && 602 isaddr.s_addr == ia->ia_addr.sin_addr.s_addr) 603 goto match; 604 /* 605 * No match, use the first inet address on the receive interface 606 * as a dummy address for the rest of the function. 607 */ 608 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) 609 if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_INET) { 610 ia = ifatoia(ifa); 611 goto match; 612 } 613 /* 614 * If bridging, fall back to using any inet address. 615 * This is probably incorrect, the right way being try to match 616 * addresses for interfaces in the same cluster, so if we 617 * get here we should always drop the packet. 618 */ 619 if (!BRIDGE_TEST || 620 (ia = TAILQ_FIRST(&in_ifaddrhead)) == NULL) { 621 m_freem(m); 622 return; 623 } 624 match: 625 myaddr = ia->ia_addr.sin_addr; 626 if (!bcmp(ar_sha(ah), IF_LLADDR(ifp), ifp->if_addrlen)) { 627 m_freem(m); /* it's from me, ignore it. */ 628 return; 629 } 630 if (!bcmp(ar_sha(ah), IF_BCASTADDR(ifp), ifp->if_addrlen)) { 631 log(LOG_ERR, 632 "arp: link address is broadcast for IP address %s!\n", 633 inet_ntoa(isaddr)); 634 m_freem(m); 635 return; 636 } 637 if (isaddr.s_addr == myaddr.s_addr) { 638 log(LOG_ERR, 639 "arp: %*D is using my IP address %s!\n", 640 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 641 inet_ntoa(isaddr)); 642 itaddr = myaddr; 643 goto reply; 644 } 645 la = arplookup(isaddr.s_addr, itaddr.s_addr == myaddr.s_addr, 0); 646 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { 647 /* the following is not an error when doing bridging */ 648 if (!BRIDGE_TEST && rt->rt_ifp != ifp) { 649 if (log_arp_wrong_iface) 650 log(LOG_ERR, "arp: %s is on %s but got reply from %*D on %s\n", 651 inet_ntoa(isaddr), 652 rt->rt_ifp->if_xname, 653 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 654 ifp->if_xname); 655 goto reply; 656 } 657 if (sdl->sdl_alen && 658 bcmp(ar_sha(ah), LLADDR(sdl), sdl->sdl_alen)) { 659 if (rt->rt_expire) 660 log(LOG_INFO, "arp: %s moved from %*D to %*D on %s\n", 661 inet_ntoa(isaddr), 662 ifp->if_addrlen, (u_char *)LLADDR(sdl), ":", 663 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 664 ifp->if_xname); 665 else { 666 log(LOG_ERR, 667 "arp: %*D attempts to modify permanent entry for %s on %s\n", 668 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 669 inet_ntoa(isaddr), ifp->if_xname); 670 goto reply; 671 } 672 } 673 /* 674 * sanity check for the address length. 675 * XXX this does not work for protocols with variable address 676 * length. -is 677 */ 678 if (sdl->sdl_alen && 679 sdl->sdl_alen != ah->ar_hln) { 680 log(LOG_WARNING, 681 "arp from %*D: new addr len %d, was %d", 682 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 683 ah->ar_hln, sdl->sdl_alen); 684 } 685 if (ifp->if_addrlen != ah->ar_hln) { 686 log(LOG_WARNING, 687 "arp from %*D: addr len: new %d, i/f %d (ignored)", 688 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 689 ah->ar_hln, ifp->if_addrlen); 690 goto reply; 691 } 692 (void)memcpy(LLADDR(sdl), ar_sha(ah), 693 sdl->sdl_alen = ah->ar_hln); 694 /* 695 * If we receive an arp from a token-ring station over 696 * a token-ring nic then try to save the source 697 * routing info. 698 */ 699 if (ifp->if_type == IFT_ISO88025) { 700 th = (struct iso88025_header *)m->m_pkthdr.header; 701 trld = SDL_ISO88025(sdl); 702 rif_len = TR_RCF_RIFLEN(th->rcf); 703 if ((th->iso88025_shost[0] & TR_RII) && 704 (rif_len > 2)) { 705 trld->trld_rcf = th->rcf; 706 trld->trld_rcf ^= htons(TR_RCF_DIR); 707 memcpy(trld->trld_route, th->rd, rif_len - 2); 708 trld->trld_rcf &= ~htons(TR_RCF_BCST_MASK); 709 /* 710 * Set up source routing information for 711 * reply packet (XXX) 712 */ 713 m->m_data -= rif_len; 714 m->m_len += rif_len; 715 m->m_pkthdr.len += rif_len; 716 } else { 717 th->iso88025_shost[0] &= ~TR_RII; 718 trld->trld_rcf = 0; 719 } 720 m->m_data -= 8; 721 m->m_len += 8; 722 m->m_pkthdr.len += 8; 723 th->rcf = trld->trld_rcf; 724 } 725 if (rt->rt_expire) 726 rt->rt_expire = time_second + arpt_keep; 727 rt->rt_flags &= ~RTF_REJECT; 728 la->la_preempt = la->la_asked = 0; 729 if (la->la_hold) { 730 (*ifp->if_output)(ifp, la->la_hold, 731 rt_key(rt), rt); 732 la->la_hold = 0; 733 } 734 } 735 reply: 736 if (op != ARPOP_REQUEST) { 737 m_freem(m); 738 return; 739 } 740 if (itaddr.s_addr == myaddr.s_addr) { 741 /* I am the target */ 742 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 743 (void)memcpy(ar_sha(ah), IF_LLADDR(ifp), ah->ar_hln); 744 } else { 745 la = arplookup(itaddr.s_addr, 0, SIN_PROXY); 746 if (la == NULL) { 747 struct sockaddr_in sin; 748 749 if (!arp_proxyall) { 750 m_freem(m); 751 return; 752 } 753 754 bzero(&sin, sizeof sin); 755 sin.sin_family = AF_INET; 756 sin.sin_len = sizeof sin; 757 sin.sin_addr = itaddr; 758 759 rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL); 760 if (!rt) { 761 m_freem(m); 762 return; 763 } 764 /* 765 * Don't send proxies for nodes on the same interface 766 * as this one came out of, or we'll get into a fight 767 * over who claims what Ether address. 768 */ 769 if (rt->rt_ifp == ifp) { 770 rtfree(rt); 771 m_freem(m); 772 return; 773 } 774 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 775 (void)memcpy(ar_sha(ah), IF_LLADDR(ifp), ah->ar_hln); 776 rtfree(rt); 777 #ifdef DEBUG_PROXY 778 printf("arp: proxying for %s\n", 779 inet_ntoa(itaddr)); 780 #endif 781 } else { 782 rt = la->la_rt; 783 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 784 sdl = SDL(rt->rt_gateway); 785 (void)memcpy(ar_sha(ah), LLADDR(sdl), ah->ar_hln); 786 } 787 } 788 789 (void)memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln); 790 (void)memcpy(ar_spa(ah), &itaddr, ah->ar_pln); 791 ah->ar_op = htons(ARPOP_REPLY); 792 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 793 switch (ifp->if_type) { 794 case IFT_ARCNET: 795 arh = (struct arc_header *)sa.sa_data; 796 arh->arc_dhost = *ar_tha(ah); 797 arh->arc_type = ARCTYPE_ARP; 798 break; 799 800 case IFT_ISO88025: 801 /* Re-arrange the source/dest address */ 802 memcpy(th->iso88025_dhost, th->iso88025_shost, 803 sizeof(th->iso88025_dhost)); 804 memcpy(th->iso88025_shost, IF_LLADDR(ifp), 805 sizeof(th->iso88025_shost)); 806 /* Set the source routing bit if neccesary */ 807 if (th->iso88025_dhost[0] & TR_RII) { 808 th->iso88025_dhost[0] &= ~TR_RII; 809 if (TR_RCF_RIFLEN(th->rcf) > 2) 810 th->iso88025_shost[0] |= TR_RII; 811 } 812 /* Copy the addresses, ac and fc into sa_data */ 813 memcpy(sa.sa_data, th->iso88025_dhost, 814 sizeof(th->iso88025_dhost) * 2); 815 sa.sa_data[(sizeof(th->iso88025_dhost) * 2)] = TR_AC; 816 sa.sa_data[(sizeof(th->iso88025_dhost) * 2) + 1] = TR_LLC_FRAME; 817 break; 818 case IFT_ETHER: 819 case IFT_FDDI: 820 /* 821 * May not be correct for types not explictly 822 * listed, but it is our best guess. 823 */ 824 default: 825 eh = (struct ether_header *)sa.sa_data; 826 (void)memcpy(eh->ether_dhost, ar_tha(ah), 827 sizeof(eh->ether_dhost)); 828 eh->ether_type = htons(ETHERTYPE_ARP); 829 break; 830 } 831 sa.sa_family = AF_UNSPEC; 832 sa.sa_len = sizeof(sa); 833 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 834 return; 835 } 836 #endif 837 838 /* 839 * Free an arp entry. 840 */ 841 static void 842 arptfree(la) 843 struct llinfo_arp *la; 844 { 845 struct rtentry *rt = la->la_rt; 846 struct sockaddr_dl *sdl; 847 if (rt == 0) 848 panic("arptfree"); 849 if (rt->rt_refcnt > 0 && (sdl = SDL(rt->rt_gateway)) && 850 sdl->sdl_family == AF_LINK) { 851 sdl->sdl_alen = 0; 852 la->la_preempt = la->la_asked = 0; 853 rt->rt_flags &= ~RTF_REJECT; 854 return; 855 } 856 rtrequest(RTM_DELETE, rt_key(rt), (struct sockaddr *)0, rt_mask(rt), 857 0, (struct rtentry **)0); 858 } 859 /* 860 * Lookup or enter a new address in arptab. 861 */ 862 static struct llinfo_arp * 863 arplookup(addr, create, proxy) 864 u_long addr; 865 int create, proxy; 866 { 867 struct rtentry *rt; 868 static struct sockaddr_inarp sin = {sizeof(sin), AF_INET }; 869 const char *why = 0; 870 871 sin.sin_addr.s_addr = addr; 872 sin.sin_other = proxy ? SIN_PROXY : 0; 873 rt = rtalloc1((struct sockaddr *)&sin, create, 0UL); 874 if (rt == 0) 875 return (0); 876 rt->rt_refcnt--; 877 878 if (rt->rt_flags & RTF_GATEWAY) 879 why = "host is not on local network"; 880 else if ((rt->rt_flags & RTF_LLINFO) == 0) 881 why = "could not allocate llinfo"; 882 else if (rt->rt_gateway->sa_family != AF_LINK) 883 why = "gateway route is not ours"; 884 885 if (why) { 886 if (create) { 887 log(LOG_DEBUG, "arplookup %s failed: %s\n", 888 inet_ntoa(sin.sin_addr), why); 889 } 890 891 /* if there are no references to this route, purge it */ 892 if (rt->rt_refcnt <= 0 && 893 (rt->rt_flags & RTF_WASCLONED) == RTF_WASCLONED) { 894 rtrequest(RTM_DELETE, 895 (struct sockaddr *)rt_key(rt), rt->rt_gateway, 896 rt_mask(rt), rt->rt_flags, 0); 897 } 898 return (0); 899 } 900 return ((struct llinfo_arp *)rt->rt_llinfo); 901 } 902 903 void 904 arp_ifinit(ifp, ifa) 905 struct ifnet *ifp; 906 struct ifaddr *ifa; 907 { 908 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY) 909 arprequest(ifp, &IA_SIN(ifa)->sin_addr, 910 &IA_SIN(ifa)->sin_addr, IF_LLADDR(ifp)); 911 ifa->ifa_rtrequest = arp_rtrequest; 912 ifa->ifa_flags |= RTF_CLONING; 913 } 914 915 static void 916 arp_init(void) 917 { 918 LIST_INIT(&llinfo_arp); 919 netisr_register(NETISR_ARP, cpu0_portfn, arpintr); 920 } 921 922 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0); 923