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 1.16 2004/11/02 23:49:30 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 <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; /* #times we QUERIED before entry expiration */ 103 u_short la_asked; /* #times we QUERIED following expiration */ 104 #define la_timer la_rt->rt_rmx.rmx_expire /* deletion time in seconds */ 105 }; 106 107 static LIST_HEAD(, llinfo_arp) llinfo_arp; 108 109 static int arp_inuse, arp_allocated, arpinit_done; 110 111 static int arp_maxtries = 5; 112 static int useloopback = 1; /* use loopback interface for local traffic */ 113 static int arp_proxyall = 0; 114 115 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW, 116 &arp_maxtries, 0, ""); 117 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW, 118 &useloopback, 0, ""); 119 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW, 120 &arp_proxyall, 0, ""); 121 122 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 int arpintr(struct netmsg *); 126 static void arptfree (struct llinfo_arp *); 127 static void arptimer (void *); 128 static struct llinfo_arp 129 *arplookup (u_long, int, int); 130 #ifdef INET 131 static void in_arpinput (struct mbuf *); 132 #endif 133 134 static struct callout arptimer_ch; 135 136 /* 137 * Timeout routine. Age arp_tab entries periodically. 138 */ 139 /* ARGSUSED */ 140 static void 141 arptimer(ignored_arg) 142 void *ignored_arg; 143 { 144 int s = splnet(); 145 struct llinfo_arp *la = LIST_FIRST(&llinfo_arp); 146 struct llinfo_arp *ola; 147 148 while ((ola = la) != 0) { 149 struct rtentry *rt = la->la_rt; 150 la = LIST_NEXT(la, la_le); 151 if (rt->rt_expire && rt->rt_expire <= time_second) 152 arptfree(ola); /* timer has expired, clear */ 153 } 154 callout_reset(&arptimer_ch, arpt_prune * hz, arptimer, NULL); 155 splx(s); 156 } 157 158 /* 159 * Parallel to llc_rtrequest. 160 */ 161 static void 162 arp_rtrequest(req, rt, info) 163 int req; 164 struct rtentry *rt; 165 struct rt_addrinfo *info; 166 { 167 struct sockaddr *gate = rt->rt_gateway; 168 struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo; 169 static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK}; 170 171 if (!arpinit_done) { 172 arpinit_done = 1; 173 callout_init(&arptimer_ch); 174 callout_reset(&arptimer_ch, hz, arptimer, NULL); 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)), rt->rt_ifp->if_broadcastaddr, 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(MB_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 = ifp->if_broadcastaddr[0]; 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 memcpy(sa.sa_data, ifp->if_broadcastaddr, ifp->if_addrlen); 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 memcpy(eh->ether_dhost, ifp->if_broadcastaddr, ifp->if_addrlen); 362 363 ah = mtod(m, struct arphdr *); 364 break; 365 } 366 367 ah->ar_hrd = ar_hrd; 368 ah->ar_pro = htons(ETHERTYPE_IP); 369 ah->ar_hln = ifp->if_addrlen; /* hardware address length */ 370 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 371 ah->ar_op = htons(ARPOP_REQUEST); 372 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln); 373 memset(ar_tha(ah), 0, ah->ar_hln); 374 (void)memcpy(ar_spa(ah), sip, ah->ar_pln); 375 (void)memcpy(ar_tpa(ah), tip, ah->ar_pln); 376 377 sa.sa_family = AF_UNSPEC; 378 sa.sa_len = sizeof(sa); 379 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 380 } 381 382 /* 383 * Resolve an IP address into an ethernet address. If success, 384 * desten is filled in. If there is no entry in arptab, 385 * set one up and broadcast a request for the IP address. 386 * Hold onto this mbuf and resend it once the address 387 * is finally resolved. A return value of 1 indicates 388 * that desten has been filled in and the packet should be sent 389 * normally; a 0 return indicates that the packet has been 390 * taken over here, either now or for later transmission. 391 */ 392 int 393 arpresolve(ifp, rt, m, dst, desten, rt0) 394 struct ifnet *ifp; 395 struct rtentry *rt; 396 struct mbuf *m; 397 struct sockaddr *dst; 398 u_char *desten; 399 struct rtentry *rt0; 400 { 401 struct llinfo_arp *la = 0; 402 struct sockaddr_dl *sdl; 403 404 if (m->m_flags & M_BCAST) { /* broadcast */ 405 memcpy(desten, ifp->if_broadcastaddr, ifp->if_addrlen); 406 return (1); 407 } 408 if (m->m_flags & M_MCAST && ifp->if_type != IFT_ARCNET) {/* multicast */ 409 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); 410 return(1); 411 } 412 if (rt) 413 la = (struct llinfo_arp *)rt->rt_llinfo; 414 if (la == 0) { 415 la = arplookup(SIN(dst)->sin_addr.s_addr, 1, 0); 416 if (la) 417 rt = la->la_rt; 418 } 419 if (la == 0 || rt == 0) { 420 log(LOG_DEBUG, "arpresolve: can't allocate llinfo for %s%s%s\n", 421 inet_ntoa(SIN(dst)->sin_addr), la ? "la" : "", 422 rt ? "rt" : ""); 423 m_freem(m); 424 return (0); 425 } 426 sdl = SDL(rt->rt_gateway); 427 /* 428 * Check the address family and length is valid, the address 429 * is resolved; otherwise, try to resolve. 430 */ 431 if ((rt->rt_expire == 0 || rt->rt_expire > time_second) && 432 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 433 /* 434 * If entry has an expiry time and it is approaching, 435 * see if we need to send an ARP request within this 436 * arpt_down interval. 437 */ 438 if ((rt->rt_expire != 0) && 439 (time_second + (arp_maxtries - la->la_preempt) * arpt_down 440 > rt->rt_expire)) { 441 arprequest(ifp, 442 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 443 &SIN(dst)->sin_addr, 444 IF_LLADDR(ifp)); 445 la->la_preempt++; 446 } 447 448 bcopy(LLADDR(sdl), desten, sdl->sdl_alen); 449 return 1; 450 } 451 /* 452 * If ARP is disabled on this interface, stop. 453 * XXX 454 * Probably should not allocate empty llinfo struct if we are 455 * not going to be sending out an arp request. 456 */ 457 if (ifp->if_flags & IFF_NOARP) { 458 m_freem(m); 459 return (0); 460 } 461 /* 462 * There is an arptab entry, but no ethernet address 463 * response yet. Replace the held mbuf with this 464 * latest one. 465 */ 466 if (la->la_hold) 467 m_freem(la->la_hold); 468 la->la_hold = m; 469 if (rt->rt_expire || ((rt->rt_flags & RTF_STATIC) && !sdl->sdl_alen)) { 470 rt->rt_flags &= ~RTF_REJECT; 471 if (la->la_asked == 0 || rt->rt_expire != time_second) { 472 rt->rt_expire = time_second; 473 if (la->la_asked++ < arp_maxtries) { 474 arprequest(ifp, 475 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 476 &SIN(dst)->sin_addr, 477 IF_LLADDR(ifp)); 478 } else { 479 rt->rt_flags |= RTF_REJECT; 480 rt->rt_expire += arpt_down; 481 la->la_preempt = la->la_asked = 0; 482 } 483 484 } 485 } 486 return (0); 487 } 488 489 /* 490 * Common length and type checks are done here, 491 * then the protocol-specific routine is called. 492 */ 493 static int 494 arpintr(struct netmsg *msg) 495 { 496 struct mbuf *m = ((struct netmsg_packet *)msg)->nm_packet; 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 goto out2; 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 goto out1; 515 } 516 517 if (m->m_pkthdr.len < arphdr_len(ar) && 518 (m = m_pullup(m, arphdr_len(ar))) == NULL) { 519 log(LOG_ERR, "arp: runt packet\n"); 520 goto out1; 521 } 522 523 switch (ntohs(ar->ar_pro)) { 524 #ifdef INET 525 case ETHERTYPE_IP: 526 in_arpinput(m); 527 goto out2; 528 #endif 529 } 530 out1: 531 m_freem(m); 532 out2: 533 lwkt_replymsg(&msg->nm_lmsg, 0); 534 return(EASYNC); 535 } 536 537 #ifdef INET 538 /* 539 * ARP for Internet protocols on 10 Mb/s Ethernet. 540 * Algorithm is that given in RFC 826. 541 * In addition, a sanity check is performed on the sender 542 * protocol address, to catch impersonators. 543 * We no longer handle negotiations for use of trailer protocol: 544 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 545 * along with IP replies if we wanted trailers sent to us, 546 * and also sent them in response to IP replies. 547 * This allowed either end to announce the desire to receive 548 * trailer packets. 549 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 550 * but formerly didn't normally send requests. 551 */ 552 static int log_arp_wrong_iface = 1; 553 554 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW, 555 &log_arp_wrong_iface, 0, 556 "log arp packets arriving on the wrong interface"); 557 558 static void 559 in_arpinput(m) 560 struct mbuf *m; 561 { 562 struct arphdr *ah; 563 struct ifnet *ifp = m->m_pkthdr.rcvif; 564 struct ether_header *eh; 565 struct arc_header *arh; 566 struct iso88025_header *th = (struct iso88025_header *)0; 567 struct iso88025_sockaddr_dl_data *trld; 568 struct llinfo_arp *la = 0; 569 struct rtentry *rt; 570 struct ifaddr *ifa; 571 struct in_ifaddr *ia; 572 struct sockaddr_dl *sdl; 573 struct sockaddr sa; 574 struct in_addr isaddr, itaddr, myaddr; 575 int op, rif_len; 576 int req_len; 577 578 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 579 if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) { 580 log(LOG_ERR, "in_arp: runt packet -- m_pullup failed\n"); 581 return; 582 } 583 584 ah = mtod(m, struct arphdr *); 585 op = ntohs(ah->ar_op); 586 (void)memcpy(&isaddr, ar_spa(ah), sizeof (isaddr)); 587 (void)memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr)); 588 #ifdef BRIDGE 589 #define BRIDGE_TEST (do_bridge) 590 #else 591 #define BRIDGE_TEST (0) /* cc will optimise the test away */ 592 #endif 593 /* 594 * For a bridge, we want to check the address irrespective 595 * of the receive interface. (This will change slightly 596 * when we have clusters of interfaces). 597 */ 598 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) 599 if ((BRIDGE_TEST || (ia->ia_ifp == ifp)) && 600 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) 601 goto match; 602 LIST_FOREACH(ia, INADDR_HASH(isaddr.s_addr), ia_hash) 603 if ((BRIDGE_TEST || (ia->ia_ifp == ifp)) && 604 isaddr.s_addr == ia->ia_addr.sin_addr.s_addr) 605 goto match; 606 /* 607 * No match, use the first inet address on the receive interface 608 * as a dummy address for the rest of the function. 609 */ 610 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) 611 if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_INET) { 612 ia = ifatoia(ifa); 613 goto match; 614 } 615 /* 616 * If bridging, fall back to using any inet address. 617 * This is probably incorrect, the right way being try to match 618 * addresses for interfaces in the same cluster, so if we 619 * get here we should always drop the packet. 620 */ 621 if (!BRIDGE_TEST || 622 (ia = TAILQ_FIRST(&in_ifaddrhead)) == NULL) { 623 m_freem(m); 624 return; 625 } 626 match: 627 myaddr = ia->ia_addr.sin_addr; 628 if (!bcmp(ar_sha(ah), IF_LLADDR(ifp), ifp->if_addrlen)) { 629 m_freem(m); /* it's from me, ignore it. */ 630 return; 631 } 632 if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) { 633 log(LOG_ERR, 634 "arp: link address is broadcast for IP address %s!\n", 635 inet_ntoa(isaddr)); 636 m_freem(m); 637 return; 638 } 639 if (isaddr.s_addr == myaddr.s_addr) { 640 log(LOG_ERR, 641 "arp: %*D is using my IP address %s!\n", 642 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 643 inet_ntoa(isaddr)); 644 itaddr = myaddr; 645 goto reply; 646 } 647 la = arplookup(isaddr.s_addr, itaddr.s_addr == myaddr.s_addr, 0); 648 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { 649 /* the following is not an error when doing bridging */ 650 if (!BRIDGE_TEST && rt->rt_ifp != ifp) { 651 if (log_arp_wrong_iface) 652 log(LOG_ERR, "arp: %s is on %s but got reply from %*D on %s\n", 653 inet_ntoa(isaddr), 654 rt->rt_ifp->if_xname, 655 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 656 ifp->if_xname); 657 goto reply; 658 } 659 if (sdl->sdl_alen && 660 bcmp(ar_sha(ah), LLADDR(sdl), sdl->sdl_alen)) { 661 if (rt->rt_expire) 662 log(LOG_INFO, "arp: %s moved from %*D to %*D on %s\n", 663 inet_ntoa(isaddr), 664 ifp->if_addrlen, (u_char *)LLADDR(sdl), ":", 665 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 666 ifp->if_xname); 667 else { 668 log(LOG_ERR, 669 "arp: %*D attempts to modify permanent entry for %s on %s\n", 670 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 671 inet_ntoa(isaddr), ifp->if_xname); 672 goto reply; 673 } 674 } 675 /* 676 * sanity check for the address length. 677 * XXX this does not work for protocols with variable address 678 * length. -is 679 */ 680 if (sdl->sdl_alen && 681 sdl->sdl_alen != ah->ar_hln) { 682 log(LOG_WARNING, 683 "arp from %*D: new addr len %d, was %d", 684 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 685 ah->ar_hln, sdl->sdl_alen); 686 } 687 if (ifp->if_addrlen != ah->ar_hln) { 688 log(LOG_WARNING, 689 "arp from %*D: addr len: new %d, i/f %d (ignored)", 690 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 691 ah->ar_hln, ifp->if_addrlen); 692 goto reply; 693 } 694 (void)memcpy(LLADDR(sdl), ar_sha(ah), 695 sdl->sdl_alen = ah->ar_hln); 696 /* 697 * If we receive an arp from a token-ring station over 698 * a token-ring nic then try to save the source 699 * routing info. 700 */ 701 if (ifp->if_type == IFT_ISO88025) { 702 th = (struct iso88025_header *)m->m_pkthdr.header; 703 trld = SDL_ISO88025(sdl); 704 rif_len = TR_RCF_RIFLEN(th->rcf); 705 if ((th->iso88025_shost[0] & TR_RII) && 706 (rif_len > 2)) { 707 trld->trld_rcf = th->rcf; 708 trld->trld_rcf ^= htons(TR_RCF_DIR); 709 memcpy(trld->trld_route, th->rd, rif_len - 2); 710 trld->trld_rcf &= ~htons(TR_RCF_BCST_MASK); 711 /* 712 * Set up source routing information for 713 * reply packet (XXX) 714 */ 715 m->m_data -= rif_len; 716 m->m_len += rif_len; 717 m->m_pkthdr.len += rif_len; 718 } else { 719 th->iso88025_shost[0] &= ~TR_RII; 720 trld->trld_rcf = 0; 721 } 722 m->m_data -= 8; 723 m->m_len += 8; 724 m->m_pkthdr.len += 8; 725 th->rcf = trld->trld_rcf; 726 } 727 if (rt->rt_expire) 728 rt->rt_expire = time_second + arpt_keep; 729 rt->rt_flags &= ~RTF_REJECT; 730 la->la_preempt = la->la_asked = 0; 731 if (la->la_hold) { 732 (*ifp->if_output)(ifp, la->la_hold, 733 rt_key(rt), rt); 734 la->la_hold = 0; 735 } 736 } 737 reply: 738 if (op != ARPOP_REQUEST) { 739 m_freem(m); 740 return; 741 } 742 if (itaddr.s_addr == myaddr.s_addr) { 743 /* I am the target */ 744 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 745 (void)memcpy(ar_sha(ah), IF_LLADDR(ifp), ah->ar_hln); 746 } else { 747 la = arplookup(itaddr.s_addr, 0, SIN_PROXY); 748 if (la == NULL) { 749 struct sockaddr_in sin; 750 751 if (!arp_proxyall) { 752 m_freem(m); 753 return; 754 } 755 756 bzero(&sin, sizeof sin); 757 sin.sin_family = AF_INET; 758 sin.sin_len = sizeof sin; 759 sin.sin_addr = itaddr; 760 761 rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL); 762 if (!rt) { 763 m_freem(m); 764 return; 765 } 766 /* 767 * Don't send proxies for nodes on the same interface 768 * as this one came out of, or we'll get into a fight 769 * over who claims what Ether address. 770 */ 771 if (rt->rt_ifp == ifp) { 772 rtfree(rt); 773 m_freem(m); 774 return; 775 } 776 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 777 (void)memcpy(ar_sha(ah), IF_LLADDR(ifp), ah->ar_hln); 778 rtfree(rt); 779 #ifdef DEBUG_PROXY 780 printf("arp: proxying for %s\n", 781 inet_ntoa(itaddr)); 782 #endif 783 } else { 784 rt = la->la_rt; 785 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 786 sdl = SDL(rt->rt_gateway); 787 (void)memcpy(ar_sha(ah), LLADDR(sdl), ah->ar_hln); 788 } 789 } 790 791 (void)memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln); 792 (void)memcpy(ar_spa(ah), &itaddr, ah->ar_pln); 793 ah->ar_op = htons(ARPOP_REPLY); 794 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 795 switch (ifp->if_type) { 796 case IFT_ARCNET: 797 arh = (struct arc_header *)sa.sa_data; 798 arh->arc_dhost = *ar_tha(ah); 799 arh->arc_type = ARCTYPE_ARP; 800 break; 801 802 case IFT_ISO88025: 803 /* Re-arrange the source/dest address */ 804 memcpy(th->iso88025_dhost, th->iso88025_shost, 805 sizeof(th->iso88025_dhost)); 806 memcpy(th->iso88025_shost, IF_LLADDR(ifp), 807 sizeof(th->iso88025_shost)); 808 /* Set the source routing bit if neccesary */ 809 if (th->iso88025_dhost[0] & TR_RII) { 810 th->iso88025_dhost[0] &= ~TR_RII; 811 if (TR_RCF_RIFLEN(th->rcf) > 2) 812 th->iso88025_shost[0] |= TR_RII; 813 } 814 /* Copy the addresses, ac and fc into sa_data */ 815 memcpy(sa.sa_data, th->iso88025_dhost, 816 sizeof(th->iso88025_dhost) * 2); 817 sa.sa_data[(sizeof(th->iso88025_dhost) * 2)] = TR_AC; 818 sa.sa_data[(sizeof(th->iso88025_dhost) * 2) + 1] = TR_LLC_FRAME; 819 break; 820 case IFT_ETHER: 821 case IFT_FDDI: 822 /* 823 * May not be correct for types not explictly 824 * listed, but it is our best guess. 825 */ 826 default: 827 eh = (struct ether_header *)sa.sa_data; 828 (void)memcpy(eh->ether_dhost, ar_tha(ah), 829 sizeof(eh->ether_dhost)); 830 eh->ether_type = htons(ETHERTYPE_ARP); 831 break; 832 } 833 sa.sa_family = AF_UNSPEC; 834 sa.sa_len = sizeof(sa); 835 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 836 return; 837 } 838 #endif 839 840 /* 841 * Free an arp entry. If the arp entry is actively referenced or represents 842 * a static entry we only clear it back to an unresolved state, otherwise 843 * we destroy the entry entirely. 844 * 845 * Note that static entries are created when route add ... -interface is used 846 * to create an interface route to a (direct) destination. 847 */ 848 static void 849 arptfree(la) 850 struct llinfo_arp *la; 851 { 852 struct rtentry *rt = la->la_rt; 853 struct sockaddr_dl *sdl; 854 if (rt == NULL) 855 panic("arptfree"); 856 sdl = SDL(rt->rt_gateway); 857 if ((rt->rt_refcnt > 0 && sdl && sdl->sdl_family == AF_LINK) || 858 (rt->rt_flags & RTF_STATIC)) { 859 sdl->sdl_alen = 0; 860 la->la_preempt = la->la_asked = 0; 861 rt->rt_flags &= ~RTF_REJECT; 862 return; 863 } 864 rtrequest(RTM_DELETE, rt_key(rt), (struct sockaddr *)0, rt_mask(rt), 865 0, (struct rtentry **)0); 866 } 867 /* 868 * Lookup or enter a new address in arptab. 869 */ 870 static struct llinfo_arp * 871 arplookup(addr, create, proxy) 872 u_long addr; 873 int create, proxy; 874 { 875 struct rtentry *rt; 876 static struct sockaddr_inarp sin = {sizeof(sin), AF_INET }; 877 const char *why = 0; 878 879 sin.sin_addr.s_addr = addr; 880 sin.sin_other = proxy ? SIN_PROXY : 0; 881 rt = rtalloc1((struct sockaddr *)&sin, create, 0UL); 882 if (rt == 0) 883 return (0); 884 rt->rt_refcnt--; 885 886 if (rt->rt_flags & RTF_GATEWAY) 887 why = "host is not on local network"; 888 else if ((rt->rt_flags & RTF_LLINFO) == 0) 889 why = "could not allocate llinfo"; 890 else if (rt->rt_gateway->sa_family != AF_LINK) 891 why = "gateway route is not ours"; 892 893 if (why) { 894 if (create) { 895 log(LOG_DEBUG, "arplookup %s failed: %s\n", 896 inet_ntoa(sin.sin_addr), why); 897 } 898 899 /* if there are no references to this route, purge it */ 900 if (rt->rt_refcnt <= 0 && 901 (rt->rt_flags & RTF_WASCLONED) == RTF_WASCLONED) { 902 rtrequest(RTM_DELETE, 903 (struct sockaddr *)rt_key(rt), rt->rt_gateway, 904 rt_mask(rt), rt->rt_flags, 0); 905 } 906 return (0); 907 } 908 return ((struct llinfo_arp *)rt->rt_llinfo); 909 } 910 911 void 912 arp_ifinit(ifp, ifa) 913 struct ifnet *ifp; 914 struct ifaddr *ifa; 915 { 916 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY) 917 arprequest(ifp, &IA_SIN(ifa)->sin_addr, 918 &IA_SIN(ifa)->sin_addr, IF_LLADDR(ifp)); 919 ifa->ifa_rtrequest = arp_rtrequest; 920 ifa->ifa_flags |= RTF_CLONING; 921 } 922 923 static void 924 arp_init(void) 925 { 926 LIST_INIT(&llinfo_arp); 927 netisr_register(NETISR_ARP, cpu0_portfn, arpintr); 928 } 929 930 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0); 931