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 1.13 2004/06/02 14:43:01 eirikn 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 u_char arcbroadcastaddr = 0; 135 136 #define IF_BCASTADDR(ifp) \ 137 ((ifp)->if_type == IFT_ARCNET ? \ 138 &arcbroadcastaddr : etherbroadcastaddr) 139 140 /* 141 * Timeout routine. Age arp_tab entries periodically. 142 */ 143 /* ARGSUSED */ 144 static void 145 arptimer(ignored_arg) 146 void *ignored_arg; 147 { 148 int s = splnet(); 149 struct llinfo_arp *la = LIST_FIRST(&llinfo_arp); 150 struct llinfo_arp *ola; 151 152 timeout(arptimer, (caddr_t)0, arpt_prune * hz); 153 while ((ola = la) != 0) { 154 struct rtentry *rt = la->la_rt; 155 la = LIST_NEXT(la, la_le); 156 if (rt->rt_expire && rt->rt_expire <= time_second) 157 arptfree(ola); /* timer has expired, clear */ 158 } 159 splx(s); 160 } 161 162 /* 163 * Parallel to llc_rtrequest. 164 */ 165 static void 166 arp_rtrequest(req, rt, info) 167 int req; 168 struct rtentry *rt; 169 struct rt_addrinfo *info; 170 { 171 struct sockaddr *gate = rt->rt_gateway; 172 struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo; 173 static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK}; 174 175 if (!arpinit_done) { 176 arpinit_done = 1; 177 timeout(arptimer, (caddr_t)0, hz); 178 } 179 if (rt->rt_flags & RTF_GATEWAY) 180 return; 181 switch (req) { 182 183 case RTM_ADD: 184 /* 185 * XXX: If this is a manually added route to interface 186 * such as older version of routed or gated might provide, 187 * restore cloning bit. 188 */ 189 if ((rt->rt_flags & RTF_HOST) == 0 && 190 SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff) 191 rt->rt_flags |= RTF_CLONING; 192 if (rt->rt_flags & RTF_CLONING) { 193 /* 194 * Case 1: This route should come from a route to iface. 195 */ 196 rt_setgate(rt, rt_key(rt), 197 (struct sockaddr *)&null_sdl); 198 gate = rt->rt_gateway; 199 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 200 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 201 rt->rt_expire = time_second; 202 break; 203 } 204 /* Announce a new entry if requested. */ 205 if (rt->rt_flags & RTF_ANNOUNCE) 206 arprequest(rt->rt_ifp, 207 &SIN(rt_key(rt))->sin_addr, 208 &SIN(rt_key(rt))->sin_addr, 209 (u_char *)LLADDR(SDL(gate))); 210 /*FALLTHROUGH*/ 211 case RTM_RESOLVE: 212 if (gate->sa_family != AF_LINK || 213 gate->sa_len < sizeof(null_sdl)) { 214 log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n"); 215 break; 216 } 217 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 218 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 219 if (la != 0) 220 break; /* This happens on a route change */ 221 /* 222 * Case 2: This route may come from cloning, or a manual route 223 * add with a LL address. 224 */ 225 R_Malloc(la, struct llinfo_arp *, sizeof(*la)); 226 rt->rt_llinfo = (caddr_t)la; 227 if (la == 0) { 228 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); 229 break; 230 } 231 arp_inuse++, arp_allocated++; 232 Bzero(la, sizeof(*la)); 233 la->la_rt = rt; 234 rt->rt_flags |= RTF_LLINFO; 235 LIST_INSERT_HEAD(&llinfo_arp, la, la_le); 236 237 #ifdef INET 238 /* 239 * This keeps the multicast addresses from showing up 240 * in `arp -a' listings as unresolved. It's not actually 241 * functional. Then the same for broadcast. 242 */ 243 if (IN_MULTICAST(ntohl(SIN(rt_key(rt))->sin_addr.s_addr)) 244 && rt->rt_ifp->if_type != IFT_ARCNET) { 245 ETHER_MAP_IP_MULTICAST(&SIN(rt_key(rt))->sin_addr, 246 LLADDR(SDL(gate))); 247 SDL(gate)->sdl_alen = 6; 248 rt->rt_expire = 0; 249 } 250 if (in_broadcast(SIN(rt_key(rt))->sin_addr, rt->rt_ifp)) { 251 memcpy(LLADDR(SDL(gate)), IF_BCASTADDR(rt->rt_ifp), 252 rt->rt_ifp->if_addrlen); 253 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen; 254 rt->rt_expire = 0; 255 } 256 #endif 257 258 if (SIN(rt_key(rt))->sin_addr.s_addr == 259 (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) { 260 /* 261 * This test used to be 262 * if (loif.if_flags & IFF_UP) 263 * It allowed local traffic to be forced 264 * through the hardware by configuring the loopback down. 265 * However, it causes problems during network configuration 266 * for boards that can't receive packets they send. 267 * It is now necessary to clear "useloopback" and remove 268 * the route to force traffic out to the hardware. 269 */ 270 rt->rt_expire = 0; 271 Bcopy(IF_LLADDR(rt->rt_ifp), LLADDR(SDL(gate)), 272 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen); 273 if (useloopback) 274 rt->rt_ifp = loif; 275 276 } 277 break; 278 279 case RTM_DELETE: 280 if (la == 0) 281 break; 282 arp_inuse--; 283 LIST_REMOVE(la, la_le); 284 rt->rt_llinfo = 0; 285 rt->rt_flags &= ~RTF_LLINFO; 286 if (la->la_hold) 287 m_freem(la->la_hold); 288 Free((caddr_t)la); 289 } 290 } 291 292 /* 293 * Broadcast an ARP request. Caller specifies: 294 * - arp header source ip address 295 * - arp header target ip address 296 * - arp header source ethernet address 297 */ 298 static void 299 arprequest(ifp, sip, tip, enaddr) 300 struct ifnet *ifp; 301 struct in_addr *sip, *tip; 302 u_char *enaddr; 303 { 304 struct mbuf *m; 305 struct ether_header *eh; 306 struct arc_header *arh; 307 struct arphdr *ah; 308 struct sockaddr sa; 309 static u_char llcx[] = { 0x82, 0x40, LLC_SNAP_LSAP, LLC_SNAP_LSAP, 310 LLC_UI, 0x00, 0x00, 0x00, 0x08, 0x06 }; 311 u_short ar_hrd; 312 313 if ((m = m_gethdr(MB_DONTWAIT, MT_DATA)) == NULL) 314 return; 315 m->m_pkthdr.rcvif = (struct ifnet *)0; 316 switch (ifp->if_type) { 317 case IFT_ARCNET: 318 ar_hrd = htons(ARPHRD_ARCNET); 319 320 m->m_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 321 m->m_pkthdr.len = m->m_len; 322 MH_ALIGN(m, m->m_len); 323 324 arh = (struct arc_header *)sa.sa_data; 325 arh->arc_dhost = arcbroadcastaddr; 326 arh->arc_type = ARCTYPE_ARP; 327 328 ah = mtod(m, struct arphdr *); 329 break; 330 331 case IFT_ISO88025: 332 ar_hrd = htons(ARPHRD_IEEE802); 333 334 m->m_len = sizeof(llcx) + 335 arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 336 m->m_pkthdr.len = m->m_len; 337 MH_ALIGN(m, m->m_len); 338 339 (void)memcpy(mtod(m, caddr_t), llcx, sizeof(llcx)); 340 (void)memcpy(sa.sa_data, etherbroadcastaddr, 6); 341 (void)memcpy(sa.sa_data + 6, enaddr, 6); 342 sa.sa_data[6] |= TR_RII; 343 sa.sa_data[12] = TR_AC; 344 sa.sa_data[13] = TR_LLC_FRAME; 345 346 ah = (struct arphdr *)(mtod(m, char *) + sizeof(llcx)); 347 break; 348 case IFT_FDDI: 349 case IFT_ETHER: 350 /* 351 * This may not be correct for types not explicitly 352 * listed, but this is our best guess 353 */ 354 default: 355 ar_hrd = htons(ARPHRD_ETHER); 356 357 m->m_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 358 m->m_pkthdr.len = m->m_len; 359 MH_ALIGN(m, m->m_len); 360 361 eh = (struct ether_header *)sa.sa_data; 362 /* if_output will not swap */ 363 eh->ether_type = htons(ETHERTYPE_ARP); 364 (void)memcpy(eh->ether_dhost, etherbroadcastaddr, 365 sizeof(eh->ether_dhost)); 366 367 ah = mtod(m, struct arphdr *); 368 break; 369 } 370 371 ah->ar_hrd = ar_hrd; 372 ah->ar_pro = htons(ETHERTYPE_IP); 373 ah->ar_hln = ifp->if_addrlen; /* hardware address length */ 374 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 375 ah->ar_op = htons(ARPOP_REQUEST); 376 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln); 377 memset(ar_tha(ah), 0, ah->ar_hln); 378 (void)memcpy(ar_spa(ah), sip, ah->ar_pln); 379 (void)memcpy(ar_tpa(ah), tip, ah->ar_pln); 380 381 sa.sa_family = AF_UNSPEC; 382 sa.sa_len = sizeof(sa); 383 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 384 } 385 386 /* 387 * Resolve an IP address into an ethernet address. If success, 388 * desten is filled in. If there is no entry in arptab, 389 * set one up and broadcast a request for the IP address. 390 * Hold onto this mbuf and resend it once the address 391 * is finally resolved. A return value of 1 indicates 392 * that desten has been filled in and the packet should be sent 393 * normally; a 0 return indicates that the packet has been 394 * taken over here, either now or for later transmission. 395 */ 396 int 397 arpresolve(ifp, rt, m, dst, desten, rt0) 398 struct ifnet *ifp; 399 struct rtentry *rt; 400 struct mbuf *m; 401 struct sockaddr *dst; 402 u_char *desten; 403 struct rtentry *rt0; 404 { 405 struct llinfo_arp *la = 0; 406 struct sockaddr_dl *sdl; 407 408 if (m->m_flags & M_BCAST) { /* broadcast */ 409 (void)memcpy(desten, IF_BCASTADDR(ifp), ifp->if_addrlen); 410 return (1); 411 } 412 if (m->m_flags & M_MCAST && ifp->if_type != IFT_ARCNET) {/* multicast */ 413 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); 414 return(1); 415 } 416 if (rt) 417 la = (struct llinfo_arp *)rt->rt_llinfo; 418 if (la == 0) { 419 la = arplookup(SIN(dst)->sin_addr.s_addr, 1, 0); 420 if (la) 421 rt = la->la_rt; 422 } 423 if (la == 0 || rt == 0) { 424 log(LOG_DEBUG, "arpresolve: can't allocate llinfo for %s%s%s\n", 425 inet_ntoa(SIN(dst)->sin_addr), la ? "la" : "", 426 rt ? "rt" : ""); 427 m_freem(m); 428 return (0); 429 } 430 sdl = SDL(rt->rt_gateway); 431 /* 432 * Check the address family and length is valid, the address 433 * is resolved; otherwise, try to resolve. 434 */ 435 if ((rt->rt_expire == 0 || rt->rt_expire > time_second) && 436 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 437 /* 438 * If entry has an expiry time and it is approaching, 439 * see if we need to send an ARP request within this 440 * arpt_down interval. 441 */ 442 if ((rt->rt_expire != 0) && 443 (time_second + (arp_maxtries - la->la_preempt) * arpt_down 444 > rt->rt_expire)) { 445 arprequest(ifp, 446 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 447 &SIN(dst)->sin_addr, 448 IF_LLADDR(ifp)); 449 la->la_preempt++; 450 } 451 452 bcopy(LLADDR(sdl), desten, sdl->sdl_alen); 453 return 1; 454 } 455 /* 456 * If ARP is disabled on this interface, stop. 457 * XXX 458 * Probably should not allocate empty llinfo struct if we are 459 * not going to be sending out an arp request. 460 */ 461 if (ifp->if_flags & IFF_NOARP) { 462 m_freem(m); 463 return (0); 464 } 465 /* 466 * There is an arptab entry, but no ethernet address 467 * response yet. Replace the held mbuf with this 468 * latest one. 469 */ 470 if (la->la_hold) 471 m_freem(la->la_hold); 472 la->la_hold = m; 473 if (rt->rt_expire) { 474 rt->rt_flags &= ~RTF_REJECT; 475 if (la->la_asked == 0 || rt->rt_expire != time_second) { 476 rt->rt_expire = time_second; 477 if (la->la_asked++ < arp_maxtries) { 478 arprequest(ifp, 479 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 480 &SIN(dst)->sin_addr, 481 IF_LLADDR(ifp)); 482 } else { 483 rt->rt_flags |= RTF_REJECT; 484 rt->rt_expire += arpt_down; 485 la->la_preempt = la->la_asked = 0; 486 } 487 488 } 489 } 490 return (0); 491 } 492 493 /* 494 * Common length and type checks are done here, 495 * then the protocol-specific routine is called. 496 */ 497 static int 498 arpintr(struct netmsg *msg) 499 { 500 struct mbuf *m = ((struct netmsg_packet *)msg)->nm_packet; 501 struct arphdr *ar; 502 u_short ar_hrd; 503 504 if (m->m_len < sizeof(struct arphdr) && 505 ((m = m_pullup(m, sizeof(struct arphdr))) == NULL)) { 506 log(LOG_ERR, "arp: runt packet -- m_pullup failed\n"); 507 goto out2; 508 } 509 ar = mtod(m, struct arphdr *); 510 511 ar_hrd = ntohs(ar->ar_hrd); 512 if (ar_hrd != ARPHRD_ETHER && 513 ar_hrd != ARPHRD_IEEE802 && 514 ar_hrd != ARPHRD_ARCNET) { 515 log(LOG_ERR, 516 "arp: unknown hardware address format (0x%2D)\n", 517 (unsigned char *)&ar->ar_hrd, ""); 518 goto out1; 519 } 520 521 if (m->m_pkthdr.len < arphdr_len(ar) && 522 (m = m_pullup(m, arphdr_len(ar))) == NULL) { 523 log(LOG_ERR, "arp: runt packet\n"); 524 goto out1; 525 } 526 527 switch (ntohs(ar->ar_pro)) { 528 #ifdef INET 529 case ETHERTYPE_IP: 530 in_arpinput(m); 531 goto out2; 532 #endif 533 } 534 out1: 535 m_freem(m); 536 out2: 537 lwkt_replymsg(&msg->nm_lmsg, 0); 538 return(EASYNC); 539 } 540 541 #ifdef INET 542 /* 543 * ARP for Internet protocols on 10 Mb/s Ethernet. 544 * Algorithm is that given in RFC 826. 545 * In addition, a sanity check is performed on the sender 546 * protocol address, to catch impersonators. 547 * We no longer handle negotiations for use of trailer protocol: 548 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 549 * along with IP replies if we wanted trailers sent to us, 550 * and also sent them in response to IP replies. 551 * This allowed either end to announce the desire to receive 552 * trailer packets. 553 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 554 * but formerly didn't normally send requests. 555 */ 556 static int log_arp_wrong_iface = 1; 557 558 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW, 559 &log_arp_wrong_iface, 0, 560 "log arp packets arriving on the wrong interface"); 561 562 static void 563 in_arpinput(m) 564 struct mbuf *m; 565 { 566 struct arphdr *ah; 567 struct ifnet *ifp = m->m_pkthdr.rcvif; 568 struct ether_header *eh; 569 struct arc_header *arh; 570 struct iso88025_header *th = (struct iso88025_header *)0; 571 struct iso88025_sockaddr_dl_data *trld; 572 struct llinfo_arp *la = 0; 573 struct rtentry *rt; 574 struct ifaddr *ifa; 575 struct in_ifaddr *ia; 576 struct sockaddr_dl *sdl; 577 struct sockaddr sa; 578 struct in_addr isaddr, itaddr, myaddr; 579 int op, rif_len; 580 int req_len; 581 582 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 583 if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) { 584 log(LOG_ERR, "in_arp: runt packet -- m_pullup failed\n"); 585 return; 586 } 587 588 ah = mtod(m, struct arphdr *); 589 op = ntohs(ah->ar_op); 590 (void)memcpy(&isaddr, ar_spa(ah), sizeof (isaddr)); 591 (void)memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr)); 592 #ifdef BRIDGE 593 #define BRIDGE_TEST (do_bridge) 594 #else 595 #define BRIDGE_TEST (0) /* cc will optimise the test away */ 596 #endif 597 /* 598 * For a bridge, we want to check the address irrespective 599 * of the receive interface. (This will change slightly 600 * when we have clusters of interfaces). 601 */ 602 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) 603 if ((BRIDGE_TEST || (ia->ia_ifp == ifp)) && 604 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) 605 goto match; 606 LIST_FOREACH(ia, INADDR_HASH(isaddr.s_addr), ia_hash) 607 if ((BRIDGE_TEST || (ia->ia_ifp == ifp)) && 608 isaddr.s_addr == ia->ia_addr.sin_addr.s_addr) 609 goto match; 610 /* 611 * No match, use the first inet address on the receive interface 612 * as a dummy address for the rest of the function. 613 */ 614 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) 615 if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_INET) { 616 ia = ifatoia(ifa); 617 goto match; 618 } 619 /* 620 * If bridging, fall back to using any inet address. 621 * This is probably incorrect, the right way being try to match 622 * addresses for interfaces in the same cluster, so if we 623 * get here we should always drop the packet. 624 */ 625 if (!BRIDGE_TEST || 626 (ia = TAILQ_FIRST(&in_ifaddrhead)) == NULL) { 627 m_freem(m); 628 return; 629 } 630 match: 631 myaddr = ia->ia_addr.sin_addr; 632 if (!bcmp(ar_sha(ah), IF_LLADDR(ifp), ifp->if_addrlen)) { 633 m_freem(m); /* it's from me, ignore it. */ 634 return; 635 } 636 if (!bcmp(ar_sha(ah), IF_BCASTADDR(ifp), ifp->if_addrlen)) { 637 log(LOG_ERR, 638 "arp: link address is broadcast for IP address %s!\n", 639 inet_ntoa(isaddr)); 640 m_freem(m); 641 return; 642 } 643 if (isaddr.s_addr == myaddr.s_addr) { 644 log(LOG_ERR, 645 "arp: %*D is using my IP address %s!\n", 646 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 647 inet_ntoa(isaddr)); 648 itaddr = myaddr; 649 goto reply; 650 } 651 la = arplookup(isaddr.s_addr, itaddr.s_addr == myaddr.s_addr, 0); 652 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { 653 /* the following is not an error when doing bridging */ 654 if (!BRIDGE_TEST && rt->rt_ifp != ifp) { 655 if (log_arp_wrong_iface) 656 log(LOG_ERR, "arp: %s is on %s but got reply from %*D on %s\n", 657 inet_ntoa(isaddr), 658 rt->rt_ifp->if_xname, 659 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 660 ifp->if_xname); 661 goto reply; 662 } 663 if (sdl->sdl_alen && 664 bcmp(ar_sha(ah), LLADDR(sdl), sdl->sdl_alen)) { 665 if (rt->rt_expire) 666 log(LOG_INFO, "arp: %s moved from %*D to %*D on %s\n", 667 inet_ntoa(isaddr), 668 ifp->if_addrlen, (u_char *)LLADDR(sdl), ":", 669 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 670 ifp->if_xname); 671 else { 672 log(LOG_ERR, 673 "arp: %*D attempts to modify permanent entry for %s on %s\n", 674 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 675 inet_ntoa(isaddr), ifp->if_xname); 676 goto reply; 677 } 678 } 679 /* 680 * sanity check for the address length. 681 * XXX this does not work for protocols with variable address 682 * length. -is 683 */ 684 if (sdl->sdl_alen && 685 sdl->sdl_alen != ah->ar_hln) { 686 log(LOG_WARNING, 687 "arp from %*D: new addr len %d, was %d", 688 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 689 ah->ar_hln, sdl->sdl_alen); 690 } 691 if (ifp->if_addrlen != ah->ar_hln) { 692 log(LOG_WARNING, 693 "arp from %*D: addr len: new %d, i/f %d (ignored)", 694 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 695 ah->ar_hln, ifp->if_addrlen); 696 goto reply; 697 } 698 (void)memcpy(LLADDR(sdl), ar_sha(ah), 699 sdl->sdl_alen = ah->ar_hln); 700 /* 701 * If we receive an arp from a token-ring station over 702 * a token-ring nic then try to save the source 703 * routing info. 704 */ 705 if (ifp->if_type == IFT_ISO88025) { 706 th = (struct iso88025_header *)m->m_pkthdr.header; 707 trld = SDL_ISO88025(sdl); 708 rif_len = TR_RCF_RIFLEN(th->rcf); 709 if ((th->iso88025_shost[0] & TR_RII) && 710 (rif_len > 2)) { 711 trld->trld_rcf = th->rcf; 712 trld->trld_rcf ^= htons(TR_RCF_DIR); 713 memcpy(trld->trld_route, th->rd, rif_len - 2); 714 trld->trld_rcf &= ~htons(TR_RCF_BCST_MASK); 715 /* 716 * Set up source routing information for 717 * reply packet (XXX) 718 */ 719 m->m_data -= rif_len; 720 m->m_len += rif_len; 721 m->m_pkthdr.len += rif_len; 722 } else { 723 th->iso88025_shost[0] &= ~TR_RII; 724 trld->trld_rcf = 0; 725 } 726 m->m_data -= 8; 727 m->m_len += 8; 728 m->m_pkthdr.len += 8; 729 th->rcf = trld->trld_rcf; 730 } 731 if (rt->rt_expire) 732 rt->rt_expire = time_second + arpt_keep; 733 rt->rt_flags &= ~RTF_REJECT; 734 la->la_preempt = la->la_asked = 0; 735 if (la->la_hold) { 736 (*ifp->if_output)(ifp, la->la_hold, 737 rt_key(rt), rt); 738 la->la_hold = 0; 739 } 740 } 741 reply: 742 if (op != ARPOP_REQUEST) { 743 m_freem(m); 744 return; 745 } 746 if (itaddr.s_addr == myaddr.s_addr) { 747 /* I am the target */ 748 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 749 (void)memcpy(ar_sha(ah), IF_LLADDR(ifp), ah->ar_hln); 750 } else { 751 la = arplookup(itaddr.s_addr, 0, SIN_PROXY); 752 if (la == NULL) { 753 struct sockaddr_in sin; 754 755 if (!arp_proxyall) { 756 m_freem(m); 757 return; 758 } 759 760 bzero(&sin, sizeof sin); 761 sin.sin_family = AF_INET; 762 sin.sin_len = sizeof sin; 763 sin.sin_addr = itaddr; 764 765 rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL); 766 if (!rt) { 767 m_freem(m); 768 return; 769 } 770 /* 771 * Don't send proxies for nodes on the same interface 772 * as this one came out of, or we'll get into a fight 773 * over who claims what Ether address. 774 */ 775 if (rt->rt_ifp == ifp) { 776 rtfree(rt); 777 m_freem(m); 778 return; 779 } 780 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 781 (void)memcpy(ar_sha(ah), IF_LLADDR(ifp), ah->ar_hln); 782 rtfree(rt); 783 #ifdef DEBUG_PROXY 784 printf("arp: proxying for %s\n", 785 inet_ntoa(itaddr)); 786 #endif 787 } else { 788 rt = la->la_rt; 789 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 790 sdl = SDL(rt->rt_gateway); 791 (void)memcpy(ar_sha(ah), LLADDR(sdl), ah->ar_hln); 792 } 793 } 794 795 (void)memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln); 796 (void)memcpy(ar_spa(ah), &itaddr, ah->ar_pln); 797 ah->ar_op = htons(ARPOP_REPLY); 798 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 799 switch (ifp->if_type) { 800 case IFT_ARCNET: 801 arh = (struct arc_header *)sa.sa_data; 802 arh->arc_dhost = *ar_tha(ah); 803 arh->arc_type = ARCTYPE_ARP; 804 break; 805 806 case IFT_ISO88025: 807 /* Re-arrange the source/dest address */ 808 memcpy(th->iso88025_dhost, th->iso88025_shost, 809 sizeof(th->iso88025_dhost)); 810 memcpy(th->iso88025_shost, IF_LLADDR(ifp), 811 sizeof(th->iso88025_shost)); 812 /* Set the source routing bit if neccesary */ 813 if (th->iso88025_dhost[0] & TR_RII) { 814 th->iso88025_dhost[0] &= ~TR_RII; 815 if (TR_RCF_RIFLEN(th->rcf) > 2) 816 th->iso88025_shost[0] |= TR_RII; 817 } 818 /* Copy the addresses, ac and fc into sa_data */ 819 memcpy(sa.sa_data, th->iso88025_dhost, 820 sizeof(th->iso88025_dhost) * 2); 821 sa.sa_data[(sizeof(th->iso88025_dhost) * 2)] = TR_AC; 822 sa.sa_data[(sizeof(th->iso88025_dhost) * 2) + 1] = TR_LLC_FRAME; 823 break; 824 case IFT_ETHER: 825 case IFT_FDDI: 826 /* 827 * May not be correct for types not explictly 828 * listed, but it is our best guess. 829 */ 830 default: 831 eh = (struct ether_header *)sa.sa_data; 832 (void)memcpy(eh->ether_dhost, ar_tha(ah), 833 sizeof(eh->ether_dhost)); 834 eh->ether_type = htons(ETHERTYPE_ARP); 835 break; 836 } 837 sa.sa_family = AF_UNSPEC; 838 sa.sa_len = sizeof(sa); 839 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 840 return; 841 } 842 #endif 843 844 /* 845 * Free an arp entry. 846 */ 847 static void 848 arptfree(la) 849 struct llinfo_arp *la; 850 { 851 struct rtentry *rt = la->la_rt; 852 struct sockaddr_dl *sdl; 853 if (rt == 0) 854 panic("arptfree"); 855 if (rt->rt_refcnt > 0 && (sdl = SDL(rt->rt_gateway)) && 856 sdl->sdl_family == AF_LINK) { 857 sdl->sdl_alen = 0; 858 la->la_preempt = la->la_asked = 0; 859 rt->rt_flags &= ~RTF_REJECT; 860 return; 861 } 862 rtrequest(RTM_DELETE, rt_key(rt), (struct sockaddr *)0, rt_mask(rt), 863 0, (struct rtentry **)0); 864 } 865 /* 866 * Lookup or enter a new address in arptab. 867 */ 868 static struct llinfo_arp * 869 arplookup(addr, create, proxy) 870 u_long addr; 871 int create, proxy; 872 { 873 struct rtentry *rt; 874 static struct sockaddr_inarp sin = {sizeof(sin), AF_INET }; 875 const char *why = 0; 876 877 sin.sin_addr.s_addr = addr; 878 sin.sin_other = proxy ? SIN_PROXY : 0; 879 rt = rtalloc1((struct sockaddr *)&sin, create, 0UL); 880 if (rt == 0) 881 return (0); 882 rt->rt_refcnt--; 883 884 if (rt->rt_flags & RTF_GATEWAY) 885 why = "host is not on local network"; 886 else if ((rt->rt_flags & RTF_LLINFO) == 0) 887 why = "could not allocate llinfo"; 888 else if (rt->rt_gateway->sa_family != AF_LINK) 889 why = "gateway route is not ours"; 890 891 if (why) { 892 if (create) { 893 log(LOG_DEBUG, "arplookup %s failed: %s\n", 894 inet_ntoa(sin.sin_addr), why); 895 } 896 897 /* if there are no references to this route, purge it */ 898 if (rt->rt_refcnt <= 0 && 899 (rt->rt_flags & RTF_WASCLONED) == RTF_WASCLONED) { 900 rtrequest(RTM_DELETE, 901 (struct sockaddr *)rt_key(rt), rt->rt_gateway, 902 rt_mask(rt), rt->rt_flags, 0); 903 } 904 return (0); 905 } 906 return ((struct llinfo_arp *)rt->rt_llinfo); 907 } 908 909 void 910 arp_ifinit(ifp, ifa) 911 struct ifnet *ifp; 912 struct ifaddr *ifa; 913 { 914 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY) 915 arprequest(ifp, &IA_SIN(ifa)->sin_addr, 916 &IA_SIN(ifa)->sin_addr, IF_LLADDR(ifp)); 917 ifa->ifa_rtrequest = arp_rtrequest; 918 ifa->ifa_flags |= RTF_CLONING; 919 } 920 921 static void 922 arp_init(void) 923 { 924 LIST_INIT(&llinfo_arp); 925 netisr_register(NETISR_ARP, cpu0_portfn, arpintr); 926 } 927 928 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0); 929