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 1.14 2004/07/17 09:43:05 joerg 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 /* 135 * Timeout routine. Age arp_tab entries periodically. 136 */ 137 /* ARGSUSED */ 138 static void 139 arptimer(ignored_arg) 140 void *ignored_arg; 141 { 142 int s = splnet(); 143 struct llinfo_arp *la = LIST_FIRST(&llinfo_arp); 144 struct llinfo_arp *ola; 145 146 timeout(arptimer, (caddr_t)0, arpt_prune * hz); 147 while ((ola = la) != 0) { 148 struct rtentry *rt = la->la_rt; 149 la = LIST_NEXT(la, la_le); 150 if (rt->rt_expire && rt->rt_expire <= time_second) 151 arptfree(ola); /* timer has expired, clear */ 152 } 153 splx(s); 154 } 155 156 /* 157 * Parallel to llc_rtrequest. 158 */ 159 static void 160 arp_rtrequest(req, rt, info) 161 int req; 162 struct rtentry *rt; 163 struct rt_addrinfo *info; 164 { 165 struct sockaddr *gate = rt->rt_gateway; 166 struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo; 167 static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK}; 168 169 if (!arpinit_done) { 170 arpinit_done = 1; 171 timeout(arptimer, (caddr_t)0, hz); 172 } 173 if (rt->rt_flags & RTF_GATEWAY) 174 return; 175 switch (req) { 176 177 case RTM_ADD: 178 /* 179 * XXX: If this is a manually added route to interface 180 * such as older version of routed or gated might provide, 181 * restore cloning bit. 182 */ 183 if ((rt->rt_flags & RTF_HOST) == 0 && 184 SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff) 185 rt->rt_flags |= RTF_CLONING; 186 if (rt->rt_flags & RTF_CLONING) { 187 /* 188 * Case 1: This route should come from a route to iface. 189 */ 190 rt_setgate(rt, rt_key(rt), 191 (struct sockaddr *)&null_sdl); 192 gate = rt->rt_gateway; 193 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 194 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 195 rt->rt_expire = time_second; 196 break; 197 } 198 /* Announce a new entry if requested. */ 199 if (rt->rt_flags & RTF_ANNOUNCE) 200 arprequest(rt->rt_ifp, 201 &SIN(rt_key(rt))->sin_addr, 202 &SIN(rt_key(rt))->sin_addr, 203 (u_char *)LLADDR(SDL(gate))); 204 /*FALLTHROUGH*/ 205 case RTM_RESOLVE: 206 if (gate->sa_family != AF_LINK || 207 gate->sa_len < sizeof(null_sdl)) { 208 log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n"); 209 break; 210 } 211 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 212 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 213 if (la != 0) 214 break; /* This happens on a route change */ 215 /* 216 * Case 2: This route may come from cloning, or a manual route 217 * add with a LL address. 218 */ 219 R_Malloc(la, struct llinfo_arp *, sizeof(*la)); 220 rt->rt_llinfo = (caddr_t)la; 221 if (la == 0) { 222 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); 223 break; 224 } 225 arp_inuse++, arp_allocated++; 226 Bzero(la, sizeof(*la)); 227 la->la_rt = rt; 228 rt->rt_flags |= RTF_LLINFO; 229 LIST_INSERT_HEAD(&llinfo_arp, la, la_le); 230 231 #ifdef INET 232 /* 233 * This keeps the multicast addresses from showing up 234 * in `arp -a' listings as unresolved. It's not actually 235 * functional. Then the same for broadcast. 236 */ 237 if (IN_MULTICAST(ntohl(SIN(rt_key(rt))->sin_addr.s_addr)) 238 && rt->rt_ifp->if_type != IFT_ARCNET) { 239 ETHER_MAP_IP_MULTICAST(&SIN(rt_key(rt))->sin_addr, 240 LLADDR(SDL(gate))); 241 SDL(gate)->sdl_alen = 6; 242 rt->rt_expire = 0; 243 } 244 if (in_broadcast(SIN(rt_key(rt))->sin_addr, rt->rt_ifp)) { 245 memcpy(LLADDR(SDL(gate)), rt->rt_ifp->if_broadcastaddr, 246 rt->rt_ifp->if_addrlen); 247 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen; 248 rt->rt_expire = 0; 249 } 250 #endif 251 252 if (SIN(rt_key(rt))->sin_addr.s_addr == 253 (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) { 254 /* 255 * This test used to be 256 * if (loif.if_flags & IFF_UP) 257 * It allowed local traffic to be forced 258 * through the hardware by configuring the loopback down. 259 * However, it causes problems during network configuration 260 * for boards that can't receive packets they send. 261 * It is now necessary to clear "useloopback" and remove 262 * the route to force traffic out to the hardware. 263 */ 264 rt->rt_expire = 0; 265 Bcopy(IF_LLADDR(rt->rt_ifp), LLADDR(SDL(gate)), 266 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen); 267 if (useloopback) 268 rt->rt_ifp = loif; 269 270 } 271 break; 272 273 case RTM_DELETE: 274 if (la == 0) 275 break; 276 arp_inuse--; 277 LIST_REMOVE(la, la_le); 278 rt->rt_llinfo = 0; 279 rt->rt_flags &= ~RTF_LLINFO; 280 if (la->la_hold) 281 m_freem(la->la_hold); 282 Free((caddr_t)la); 283 } 284 } 285 286 /* 287 * Broadcast an ARP request. Caller specifies: 288 * - arp header source ip address 289 * - arp header target ip address 290 * - arp header source ethernet address 291 */ 292 static void 293 arprequest(ifp, sip, tip, enaddr) 294 struct ifnet *ifp; 295 struct in_addr *sip, *tip; 296 u_char *enaddr; 297 { 298 struct mbuf *m; 299 struct ether_header *eh; 300 struct arc_header *arh; 301 struct arphdr *ah; 302 struct sockaddr sa; 303 static u_char llcx[] = { 0x82, 0x40, LLC_SNAP_LSAP, LLC_SNAP_LSAP, 304 LLC_UI, 0x00, 0x00, 0x00, 0x08, 0x06 }; 305 u_short ar_hrd; 306 307 if ((m = m_gethdr(MB_DONTWAIT, MT_DATA)) == NULL) 308 return; 309 m->m_pkthdr.rcvif = (struct ifnet *)0; 310 switch (ifp->if_type) { 311 case IFT_ARCNET: 312 ar_hrd = htons(ARPHRD_ARCNET); 313 314 m->m_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 315 m->m_pkthdr.len = m->m_len; 316 MH_ALIGN(m, m->m_len); 317 318 arh = (struct arc_header *)sa.sa_data; 319 arh->arc_dhost = ifp->if_broadcastaddr[0]; 320 arh->arc_type = ARCTYPE_ARP; 321 322 ah = mtod(m, struct arphdr *); 323 break; 324 325 case IFT_ISO88025: 326 ar_hrd = htons(ARPHRD_IEEE802); 327 328 m->m_len = sizeof(llcx) + 329 arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 330 m->m_pkthdr.len = m->m_len; 331 MH_ALIGN(m, m->m_len); 332 333 (void)memcpy(mtod(m, caddr_t), llcx, sizeof(llcx)); 334 memcpy(sa.sa_data, ifp->if_broadcastaddr, ifp->if_addrlen); 335 (void)memcpy(sa.sa_data + 6, enaddr, 6); 336 sa.sa_data[6] |= TR_RII; 337 sa.sa_data[12] = TR_AC; 338 sa.sa_data[13] = TR_LLC_FRAME; 339 340 ah = (struct arphdr *)(mtod(m, char *) + sizeof(llcx)); 341 break; 342 case IFT_FDDI: 343 case IFT_ETHER: 344 /* 345 * This may not be correct for types not explicitly 346 * listed, but this is our best guess 347 */ 348 default: 349 ar_hrd = htons(ARPHRD_ETHER); 350 351 m->m_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 352 m->m_pkthdr.len = m->m_len; 353 MH_ALIGN(m, m->m_len); 354 355 eh = (struct ether_header *)sa.sa_data; 356 /* if_output will not swap */ 357 eh->ether_type = htons(ETHERTYPE_ARP); 358 memcpy(eh->ether_dhost, ifp->if_broadcastaddr, ifp->if_addrlen); 359 360 ah = mtod(m, struct arphdr *); 361 break; 362 } 363 364 ah->ar_hrd = ar_hrd; 365 ah->ar_pro = htons(ETHERTYPE_IP); 366 ah->ar_hln = ifp->if_addrlen; /* hardware address length */ 367 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 368 ah->ar_op = htons(ARPOP_REQUEST); 369 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln); 370 memset(ar_tha(ah), 0, ah->ar_hln); 371 (void)memcpy(ar_spa(ah), sip, ah->ar_pln); 372 (void)memcpy(ar_tpa(ah), tip, ah->ar_pln); 373 374 sa.sa_family = AF_UNSPEC; 375 sa.sa_len = sizeof(sa); 376 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 377 } 378 379 /* 380 * Resolve an IP address into an ethernet address. If success, 381 * desten is filled in. If there is no entry in arptab, 382 * set one up and broadcast a request for the IP address. 383 * Hold onto this mbuf and resend it once the address 384 * is finally resolved. A return value of 1 indicates 385 * that desten has been filled in and the packet should be sent 386 * normally; a 0 return indicates that the packet has been 387 * taken over here, either now or for later transmission. 388 */ 389 int 390 arpresolve(ifp, rt, m, dst, desten, rt0) 391 struct ifnet *ifp; 392 struct rtentry *rt; 393 struct mbuf *m; 394 struct sockaddr *dst; 395 u_char *desten; 396 struct rtentry *rt0; 397 { 398 struct llinfo_arp *la = 0; 399 struct sockaddr_dl *sdl; 400 401 if (m->m_flags & M_BCAST) { /* broadcast */ 402 memcpy(desten, ifp->if_broadcastaddr, ifp->if_addrlen); 403 return (1); 404 } 405 if (m->m_flags & M_MCAST && ifp->if_type != IFT_ARCNET) {/* multicast */ 406 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); 407 return(1); 408 } 409 if (rt) 410 la = (struct llinfo_arp *)rt->rt_llinfo; 411 if (la == 0) { 412 la = arplookup(SIN(dst)->sin_addr.s_addr, 1, 0); 413 if (la) 414 rt = la->la_rt; 415 } 416 if (la == 0 || rt == 0) { 417 log(LOG_DEBUG, "arpresolve: can't allocate llinfo for %s%s%s\n", 418 inet_ntoa(SIN(dst)->sin_addr), la ? "la" : "", 419 rt ? "rt" : ""); 420 m_freem(m); 421 return (0); 422 } 423 sdl = SDL(rt->rt_gateway); 424 /* 425 * Check the address family and length is valid, the address 426 * is resolved; otherwise, try to resolve. 427 */ 428 if ((rt->rt_expire == 0 || rt->rt_expire > time_second) && 429 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 430 /* 431 * If entry has an expiry time and it is approaching, 432 * see if we need to send an ARP request within this 433 * arpt_down interval. 434 */ 435 if ((rt->rt_expire != 0) && 436 (time_second + (arp_maxtries - la->la_preempt) * arpt_down 437 > rt->rt_expire)) { 438 arprequest(ifp, 439 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 440 &SIN(dst)->sin_addr, 441 IF_LLADDR(ifp)); 442 la->la_preempt++; 443 } 444 445 bcopy(LLADDR(sdl), desten, sdl->sdl_alen); 446 return 1; 447 } 448 /* 449 * If ARP is disabled on this interface, stop. 450 * XXX 451 * Probably should not allocate empty llinfo struct if we are 452 * not going to be sending out an arp request. 453 */ 454 if (ifp->if_flags & IFF_NOARP) { 455 m_freem(m); 456 return (0); 457 } 458 /* 459 * There is an arptab entry, but no ethernet address 460 * response yet. Replace the held mbuf with this 461 * latest one. 462 */ 463 if (la->la_hold) 464 m_freem(la->la_hold); 465 la->la_hold = m; 466 if (rt->rt_expire) { 467 rt->rt_flags &= ~RTF_REJECT; 468 if (la->la_asked == 0 || rt->rt_expire != time_second) { 469 rt->rt_expire = time_second; 470 if (la->la_asked++ < arp_maxtries) { 471 arprequest(ifp, 472 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 473 &SIN(dst)->sin_addr, 474 IF_LLADDR(ifp)); 475 } else { 476 rt->rt_flags |= RTF_REJECT; 477 rt->rt_expire += arpt_down; 478 la->la_preempt = la->la_asked = 0; 479 } 480 481 } 482 } 483 return (0); 484 } 485 486 /* 487 * Common length and type checks are done here, 488 * then the protocol-specific routine is called. 489 */ 490 static int 491 arpintr(struct netmsg *msg) 492 { 493 struct mbuf *m = ((struct netmsg_packet *)msg)->nm_packet; 494 struct arphdr *ar; 495 u_short ar_hrd; 496 497 if (m->m_len < sizeof(struct arphdr) && 498 ((m = m_pullup(m, sizeof(struct arphdr))) == NULL)) { 499 log(LOG_ERR, "arp: runt packet -- m_pullup failed\n"); 500 goto out2; 501 } 502 ar = mtod(m, struct arphdr *); 503 504 ar_hrd = ntohs(ar->ar_hrd); 505 if (ar_hrd != ARPHRD_ETHER && 506 ar_hrd != ARPHRD_IEEE802 && 507 ar_hrd != ARPHRD_ARCNET) { 508 log(LOG_ERR, 509 "arp: unknown hardware address format (0x%2D)\n", 510 (unsigned char *)&ar->ar_hrd, ""); 511 goto out1; 512 } 513 514 if (m->m_pkthdr.len < arphdr_len(ar) && 515 (m = m_pullup(m, arphdr_len(ar))) == NULL) { 516 log(LOG_ERR, "arp: runt packet\n"); 517 goto out1; 518 } 519 520 switch (ntohs(ar->ar_pro)) { 521 #ifdef INET 522 case ETHERTYPE_IP: 523 in_arpinput(m); 524 goto out2; 525 #endif 526 } 527 out1: 528 m_freem(m); 529 out2: 530 lwkt_replymsg(&msg->nm_lmsg, 0); 531 return(EASYNC); 532 } 533 534 #ifdef INET 535 /* 536 * ARP for Internet protocols on 10 Mb/s Ethernet. 537 * Algorithm is that given in RFC 826. 538 * In addition, a sanity check is performed on the sender 539 * protocol address, to catch impersonators. 540 * We no longer handle negotiations for use of trailer protocol: 541 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 542 * along with IP replies if we wanted trailers sent to us, 543 * and also sent them in response to IP replies. 544 * This allowed either end to announce the desire to receive 545 * trailer packets. 546 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 547 * but formerly didn't normally send requests. 548 */ 549 static int log_arp_wrong_iface = 1; 550 551 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW, 552 &log_arp_wrong_iface, 0, 553 "log arp packets arriving on the wrong interface"); 554 555 static void 556 in_arpinput(m) 557 struct mbuf *m; 558 { 559 struct arphdr *ah; 560 struct ifnet *ifp = m->m_pkthdr.rcvif; 561 struct ether_header *eh; 562 struct arc_header *arh; 563 struct iso88025_header *th = (struct iso88025_header *)0; 564 struct iso88025_sockaddr_dl_data *trld; 565 struct llinfo_arp *la = 0; 566 struct rtentry *rt; 567 struct ifaddr *ifa; 568 struct in_ifaddr *ia; 569 struct sockaddr_dl *sdl; 570 struct sockaddr sa; 571 struct in_addr isaddr, itaddr, myaddr; 572 int op, rif_len; 573 int req_len; 574 575 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 576 if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) { 577 log(LOG_ERR, "in_arp: runt packet -- m_pullup failed\n"); 578 return; 579 } 580 581 ah = mtod(m, struct arphdr *); 582 op = ntohs(ah->ar_op); 583 (void)memcpy(&isaddr, ar_spa(ah), sizeof (isaddr)); 584 (void)memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr)); 585 #ifdef BRIDGE 586 #define BRIDGE_TEST (do_bridge) 587 #else 588 #define BRIDGE_TEST (0) /* cc will optimise the test away */ 589 #endif 590 /* 591 * For a bridge, we want to check the address irrespective 592 * of the receive interface. (This will change slightly 593 * when we have clusters of interfaces). 594 */ 595 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) 596 if ((BRIDGE_TEST || (ia->ia_ifp == ifp)) && 597 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) 598 goto match; 599 LIST_FOREACH(ia, INADDR_HASH(isaddr.s_addr), ia_hash) 600 if ((BRIDGE_TEST || (ia->ia_ifp == ifp)) && 601 isaddr.s_addr == ia->ia_addr.sin_addr.s_addr) 602 goto match; 603 /* 604 * No match, use the first inet address on the receive interface 605 * as a dummy address for the rest of the function. 606 */ 607 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) 608 if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_INET) { 609 ia = ifatoia(ifa); 610 goto match; 611 } 612 /* 613 * If bridging, fall back to using any inet address. 614 * This is probably incorrect, the right way being try to match 615 * addresses for interfaces in the same cluster, so if we 616 * get here we should always drop the packet. 617 */ 618 if (!BRIDGE_TEST || 619 (ia = TAILQ_FIRST(&in_ifaddrhead)) == NULL) { 620 m_freem(m); 621 return; 622 } 623 match: 624 myaddr = ia->ia_addr.sin_addr; 625 if (!bcmp(ar_sha(ah), IF_LLADDR(ifp), ifp->if_addrlen)) { 626 m_freem(m); /* it's from me, ignore it. */ 627 return; 628 } 629 if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) { 630 log(LOG_ERR, 631 "arp: link address is broadcast for IP address %s!\n", 632 inet_ntoa(isaddr)); 633 m_freem(m); 634 return; 635 } 636 if (isaddr.s_addr == myaddr.s_addr) { 637 log(LOG_ERR, 638 "arp: %*D is using my IP address %s!\n", 639 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 640 inet_ntoa(isaddr)); 641 itaddr = myaddr; 642 goto reply; 643 } 644 la = arplookup(isaddr.s_addr, itaddr.s_addr == myaddr.s_addr, 0); 645 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { 646 /* the following is not an error when doing bridging */ 647 if (!BRIDGE_TEST && rt->rt_ifp != ifp) { 648 if (log_arp_wrong_iface) 649 log(LOG_ERR, "arp: %s is on %s but got reply from %*D on %s\n", 650 inet_ntoa(isaddr), 651 rt->rt_ifp->if_xname, 652 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 653 ifp->if_xname); 654 goto reply; 655 } 656 if (sdl->sdl_alen && 657 bcmp(ar_sha(ah), LLADDR(sdl), sdl->sdl_alen)) { 658 if (rt->rt_expire) 659 log(LOG_INFO, "arp: %s moved from %*D to %*D on %s\n", 660 inet_ntoa(isaddr), 661 ifp->if_addrlen, (u_char *)LLADDR(sdl), ":", 662 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 663 ifp->if_xname); 664 else { 665 log(LOG_ERR, 666 "arp: %*D attempts to modify permanent entry for %s on %s\n", 667 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 668 inet_ntoa(isaddr), ifp->if_xname); 669 goto reply; 670 } 671 } 672 /* 673 * sanity check for the address length. 674 * XXX this does not work for protocols with variable address 675 * length. -is 676 */ 677 if (sdl->sdl_alen && 678 sdl->sdl_alen != ah->ar_hln) { 679 log(LOG_WARNING, 680 "arp from %*D: new addr len %d, was %d", 681 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 682 ah->ar_hln, sdl->sdl_alen); 683 } 684 if (ifp->if_addrlen != ah->ar_hln) { 685 log(LOG_WARNING, 686 "arp from %*D: addr len: new %d, i/f %d (ignored)", 687 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 688 ah->ar_hln, ifp->if_addrlen); 689 goto reply; 690 } 691 (void)memcpy(LLADDR(sdl), ar_sha(ah), 692 sdl->sdl_alen = ah->ar_hln); 693 /* 694 * If we receive an arp from a token-ring station over 695 * a token-ring nic then try to save the source 696 * routing info. 697 */ 698 if (ifp->if_type == IFT_ISO88025) { 699 th = (struct iso88025_header *)m->m_pkthdr.header; 700 trld = SDL_ISO88025(sdl); 701 rif_len = TR_RCF_RIFLEN(th->rcf); 702 if ((th->iso88025_shost[0] & TR_RII) && 703 (rif_len > 2)) { 704 trld->trld_rcf = th->rcf; 705 trld->trld_rcf ^= htons(TR_RCF_DIR); 706 memcpy(trld->trld_route, th->rd, rif_len - 2); 707 trld->trld_rcf &= ~htons(TR_RCF_BCST_MASK); 708 /* 709 * Set up source routing information for 710 * reply packet (XXX) 711 */ 712 m->m_data -= rif_len; 713 m->m_len += rif_len; 714 m->m_pkthdr.len += rif_len; 715 } else { 716 th->iso88025_shost[0] &= ~TR_RII; 717 trld->trld_rcf = 0; 718 } 719 m->m_data -= 8; 720 m->m_len += 8; 721 m->m_pkthdr.len += 8; 722 th->rcf = trld->trld_rcf; 723 } 724 if (rt->rt_expire) 725 rt->rt_expire = time_second + arpt_keep; 726 rt->rt_flags &= ~RTF_REJECT; 727 la->la_preempt = la->la_asked = 0; 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. 839 */ 840 static void 841 arptfree(la) 842 struct llinfo_arp *la; 843 { 844 struct rtentry *rt = la->la_rt; 845 struct sockaddr_dl *sdl; 846 if (rt == 0) 847 panic("arptfree"); 848 if (rt->rt_refcnt > 0 && (sdl = SDL(rt->rt_gateway)) && 849 sdl->sdl_family == AF_LINK) { 850 sdl->sdl_alen = 0; 851 la->la_preempt = la->la_asked = 0; 852 rt->rt_flags &= ~RTF_REJECT; 853 return; 854 } 855 rtrequest(RTM_DELETE, rt_key(rt), (struct sockaddr *)0, rt_mask(rt), 856 0, (struct rtentry **)0); 857 } 858 /* 859 * Lookup or enter a new address in arptab. 860 */ 861 static struct llinfo_arp * 862 arplookup(addr, create, proxy) 863 u_long addr; 864 int create, proxy; 865 { 866 struct rtentry *rt; 867 static struct sockaddr_inarp sin = {sizeof(sin), AF_INET }; 868 const char *why = 0; 869 870 sin.sin_addr.s_addr = addr; 871 sin.sin_other = proxy ? SIN_PROXY : 0; 872 rt = rtalloc1((struct sockaddr *)&sin, create, 0UL); 873 if (rt == 0) 874 return (0); 875 rt->rt_refcnt--; 876 877 if (rt->rt_flags & RTF_GATEWAY) 878 why = "host is not on local network"; 879 else if ((rt->rt_flags & RTF_LLINFO) == 0) 880 why = "could not allocate llinfo"; 881 else if (rt->rt_gateway->sa_family != AF_LINK) 882 why = "gateway route is not ours"; 883 884 if (why) { 885 if (create) { 886 log(LOG_DEBUG, "arplookup %s failed: %s\n", 887 inet_ntoa(sin.sin_addr), why); 888 } 889 890 /* if there are no references to this route, purge it */ 891 if (rt->rt_refcnt <= 0 && 892 (rt->rt_flags & RTF_WASCLONED) == RTF_WASCLONED) { 893 rtrequest(RTM_DELETE, 894 (struct sockaddr *)rt_key(rt), rt->rt_gateway, 895 rt_mask(rt), rt->rt_flags, 0); 896 } 897 return (0); 898 } 899 return ((struct llinfo_arp *)rt->rt_llinfo); 900 } 901 902 void 903 arp_ifinit(ifp, ifa) 904 struct ifnet *ifp; 905 struct ifaddr *ifa; 906 { 907 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY) 908 arprequest(ifp, &IA_SIN(ifa)->sin_addr, 909 &IA_SIN(ifa)->sin_addr, IF_LLADDR(ifp)); 910 ifa->ifa_rtrequest = arp_rtrequest; 911 ifa->ifa_flags |= RTF_CLONING; 912 } 913 914 static void 915 arp_init(void) 916 { 917 LIST_INIT(&llinfo_arp); 918 netisr_register(NETISR_ARP, cpu0_portfn, arpintr); 919 } 920 921 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0); 922