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 1.21 2004/12/21 02:54:15 hsu Exp $ 36 */ 37 38 /* 39 * Ethernet address resolution protocol. 40 * TODO: 41 * add "inuse/lock" bit (or ref. count) along with valid bit 42 */ 43 44 #include "opt_inet.h" 45 #include "opt_bdg.h" 46 47 #include <sys/param.h> 48 #include <sys/kernel.h> 49 #include <sys/queue.h> 50 #include <sys/sysctl.h> 51 #include <sys/systm.h> 52 #include <sys/mbuf.h> 53 #include <sys/malloc.h> 54 #include <sys/socket.h> 55 #include <sys/syslog.h> 56 57 #include <sys/thread2.h> 58 #include <sys/msgport2.h> 59 60 #include <net/if.h> 61 #include <net/if_dl.h> 62 #include <net/if_types.h> 63 #include <net/route.h> 64 #include <net/netisr.h> 65 #include <net/if_llc.h> 66 #ifdef BRIDGE 67 #include <net/ethernet.h> 68 #include <net/bridge/bridge.h> 69 #endif 70 71 #include <netinet/in.h> 72 #include <netinet/in_var.h> 73 #include <netinet/if_ether.h> 74 75 #include <net/if_arc.h> 76 #include <net/iso88025.h> 77 78 #define SIN(s) ((struct sockaddr_in *)s) 79 #define SDL(s) ((struct sockaddr_dl *)s) 80 81 SYSCTL_DECL(_net_link_ether); 82 SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, ""); 83 84 /* timer values */ 85 static int arpt_prune = (5*60*1); /* walk list every 5 minutes */ 86 static int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */ 87 static int arpt_down = 20; /* once declared down, don't send for 20 sec */ 88 89 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, prune_intvl, CTLFLAG_RW, 90 &arpt_prune, 0, ""); 91 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW, 92 &arpt_keep, 0, ""); 93 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, host_down_time, CTLFLAG_RW, 94 &arpt_down, 0, ""); 95 96 #define rt_expire rt_rmx.rmx_expire 97 98 struct llinfo_arp { 99 LIST_ENTRY(llinfo_arp) la_le; 100 struct rtentry *la_rt; 101 struct mbuf *la_hold; /* last packet until resolved/timeout */ 102 u_short la_preempt; /* countdown for pre-expiry arps */ 103 u_short la_asked; /* #times we QUERIED following expiration */ 104 }; 105 106 static LIST_HEAD(, llinfo_arp) llinfo_arp; 107 108 static int arp_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 int arpintr(struct netmsg *); 123 static void arptfree (struct llinfo_arp *); 124 static void arptimer (void *); 125 static struct llinfo_arp 126 *arplookup (in_addr_t addr, boolean_t create, boolean_t proxy); 127 #ifdef INET 128 static void in_arpinput (struct mbuf *); 129 #endif 130 131 static struct callout arptimer_ch; 132 133 /* 134 * Timeout routine. Age arp_tab entries periodically. 135 */ 136 /* ARGSUSED */ 137 static void 138 arptimer(void *ignored_arg) 139 { 140 int s = splnet(); 141 struct llinfo_arp *la, *nla; 142 143 LIST_FOREACH_MUTABLE(la, &llinfo_arp, la_le, nla) { 144 if (la->la_rt->rt_expire && la->la_rt->rt_expire <= time_second) 145 arptfree(la); /* might remove la from llinfo_arp! */ 146 } 147 callout_reset(&arptimer_ch, arpt_prune * hz, arptimer, NULL); 148 splx(s); 149 } 150 151 /* 152 * Parallel to llc_rtrequest. 153 */ 154 static void 155 arp_rtrequest(int req, struct rtentry *rt, struct rt_addrinfo *info) 156 { 157 struct sockaddr *gate = rt->rt_gateway; 158 struct llinfo_arp *la = rt->rt_llinfo; 159 160 struct sockaddr_dl null_sdl = { sizeof(null_sdl), AF_LINK }; 161 static boolean_t arpinit_done; 162 static int arp_inuse, arp_allocated; /* for debugging only */ 163 164 if (!arpinit_done) { 165 arpinit_done = TRUE; 166 callout_init(&arptimer_ch); 167 callout_reset(&arptimer_ch, hz, arptimer, NULL); 168 } 169 if (rt->rt_flags & RTF_GATEWAY) 170 return; 171 172 switch (req) { 173 case RTM_ADD: 174 /* 175 * XXX: If this is a manually added route to interface 176 * such as older version of routed or gated might provide, 177 * restore cloning bit. 178 */ 179 if (!(rt->rt_flags & RTF_HOST) && 180 SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff) 181 rt->rt_flags |= RTF_CLONING; 182 if (rt->rt_flags & RTF_CLONING) { 183 /* 184 * Case 1: This route should come from a route to iface. 185 */ 186 rt_setgate(rt, rt_key(rt), 187 (struct sockaddr *)&null_sdl); 188 gate = rt->rt_gateway; 189 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 190 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 191 rt->rt_expire = time_second; 192 break; 193 } 194 /* Announce a new entry if requested. */ 195 if (rt->rt_flags & RTF_ANNOUNCE) 196 arprequest(rt->rt_ifp, 197 &SIN(rt_key(rt))->sin_addr, 198 &SIN(rt_key(rt))->sin_addr, 199 LLADDR(SDL(gate))); 200 /*FALLTHROUGH*/ 201 case RTM_RESOLVE: 202 if (gate->sa_family != AF_LINK || 203 gate->sa_len < sizeof(struct sockaddr_dl)) { 204 log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n"); 205 break; 206 } 207 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 208 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 209 if (la != NULL) 210 break; /* This happens on a route change */ 211 /* 212 * Case 2: This route may come from cloning, or a manual route 213 * add with a LL address. 214 */ 215 R_Malloc(la, struct llinfo_arp *, sizeof(*la)); 216 rt->rt_llinfo = la; 217 if (la == NULL) { 218 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); 219 break; 220 } 221 arp_inuse++, arp_allocated++; 222 bzero(la, sizeof *la); 223 la->la_rt = rt; 224 rt->rt_flags |= RTF_LLINFO; 225 LIST_INSERT_HEAD(&llinfo_arp, la, la_le); 226 227 #ifdef INET 228 /* 229 * This keeps the multicast addresses from showing up 230 * in `arp -a' listings as unresolved. It's not actually 231 * functional. Then the same for broadcast. 232 */ 233 if (IN_MULTICAST(ntohl(SIN(rt_key(rt))->sin_addr.s_addr)) && 234 rt->rt_ifp->if_type != IFT_ARCNET) { 235 ETHER_MAP_IP_MULTICAST(&SIN(rt_key(rt))->sin_addr, 236 LLADDR(SDL(gate))); 237 SDL(gate)->sdl_alen = 6; 238 rt->rt_expire = 0; 239 } 240 if (in_broadcast(SIN(rt_key(rt))->sin_addr, rt->rt_ifp)) { 241 memcpy(LLADDR(SDL(gate)), rt->rt_ifp->if_broadcastaddr, 242 rt->rt_ifp->if_addrlen); 243 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen; 244 rt->rt_expire = 0; 245 } 246 #endif 247 248 if (SIN(rt_key(rt))->sin_addr.s_addr == 249 (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) { 250 /* 251 * This test used to be 252 * if (loif.if_flags & IFF_UP) 253 * It allowed local traffic to be forced 254 * through the hardware by configuring the 255 * loopback down. However, it causes problems 256 * during network configuration for boards 257 * that can't receive packets they send. It 258 * is now necessary to clear "useloopback" and 259 * remove the route to force traffic out to 260 * the hardware. 261 */ 262 rt->rt_expire = 0; 263 bcopy(IF_LLADDR(rt->rt_ifp), LLADDR(SDL(gate)), 264 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen); 265 if (useloopback) 266 rt->rt_ifp = loif; 267 } 268 break; 269 270 case RTM_DELETE: 271 if (la == NULL) 272 break; 273 arp_inuse--; 274 LIST_REMOVE(la, la_le); 275 rt->rt_llinfo = NULL; 276 rt->rt_flags &= ~RTF_LLINFO; 277 if (la->la_hold != NULL) 278 m_freem(la->la_hold); 279 Free(la); 280 } 281 } 282 283 /* 284 * Broadcast an ARP request. Caller specifies: 285 * - arp header source ip address 286 * - arp header target ip address 287 * - arp header source ethernet address 288 */ 289 static void 290 arprequest(struct ifnet *ifp, struct in_addr *sip, struct in_addr *tip, 291 u_char *enaddr) 292 { 293 struct mbuf *m; 294 struct ether_header *eh; 295 struct arc_header *arh; 296 struct arphdr *ah; 297 struct sockaddr sa; 298 static u_char llcx[] = { 0x82, 0x40, LLC_SNAP_LSAP, LLC_SNAP_LSAP, 299 LLC_UI, 0x00, 0x00, 0x00, 0x08, 0x06 }; 300 u_short ar_hrd; 301 302 if ((m = m_gethdr(MB_DONTWAIT, MT_DATA)) == NULL) 303 return; 304 m->m_pkthdr.rcvif = (struct ifnet *)NULL; 305 306 switch (ifp->if_type) { 307 case IFT_ARCNET: 308 ar_hrd = htons(ARPHRD_ARCNET); 309 310 m->m_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 311 m->m_pkthdr.len = m->m_len; 312 MH_ALIGN(m, m->m_len); 313 314 arh = (struct arc_header *)sa.sa_data; 315 arh->arc_dhost = ifp->if_broadcastaddr[0]; 316 arh->arc_type = ARCTYPE_ARP; 317 318 ah = mtod(m, struct arphdr *); 319 break; 320 321 case IFT_ISO88025: 322 ar_hrd = htons(ARPHRD_IEEE802); 323 324 m->m_len = sizeof(llcx) + 325 arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 326 m->m_pkthdr.len = m->m_len; 327 MH_ALIGN(m, m->m_len); 328 329 memcpy(mtod(m, caddr_t), llcx, sizeof(llcx)); 330 memcpy(sa.sa_data, ifp->if_broadcastaddr, ifp->if_addrlen); 331 memcpy(sa.sa_data + 6, enaddr, 6); 332 sa.sa_data[6] |= TR_RII; 333 sa.sa_data[12] = TR_AC; 334 sa.sa_data[13] = TR_LLC_FRAME; 335 336 ah = (struct arphdr *)(mtod(m, char *) + sizeof(llcx)); 337 break; 338 case IFT_FDDI: 339 case IFT_ETHER: 340 /* 341 * This may not be correct for types not explicitly 342 * listed, but this is our best guess 343 */ 344 default: 345 ar_hrd = htons(ARPHRD_ETHER); 346 347 m->m_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 348 m->m_pkthdr.len = m->m_len; 349 MH_ALIGN(m, m->m_len); 350 351 eh = (struct ether_header *)sa.sa_data; 352 /* if_output() will not swap */ 353 eh->ether_type = htons(ETHERTYPE_ARP); 354 memcpy(eh->ether_dhost, ifp->if_broadcastaddr, ifp->if_addrlen); 355 356 ah = mtod(m, struct arphdr *); 357 break; 358 } 359 360 ah->ar_hrd = ar_hrd; 361 ah->ar_pro = htons(ETHERTYPE_IP); 362 ah->ar_hln = ifp->if_addrlen; /* hardware address length */ 363 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 364 ah->ar_op = htons(ARPOP_REQUEST); 365 memcpy(ar_sha(ah), enaddr, ah->ar_hln); 366 memset(ar_tha(ah), 0, ah->ar_hln); 367 memcpy(ar_spa(ah), sip, ah->ar_pln); 368 memcpy(ar_tpa(ah), tip, ah->ar_pln); 369 370 sa.sa_family = AF_UNSPEC; 371 sa.sa_len = sizeof(sa); 372 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)NULL); 373 } 374 375 /* 376 * Resolve an IP address into an ethernet address. If success, 377 * desten is filled in. If there is no entry in arptab, 378 * set one up and broadcast a request for the IP address. 379 * Hold onto this mbuf and resend it once the address 380 * is finally resolved. A return value of 1 indicates 381 * that desten has been filled in and the packet should be sent 382 * normally; a 0 return indicates that the packet has been 383 * taken over here, either now or for later transmission. 384 */ 385 int 386 arpresolve( 387 struct ifnet *ifp, 388 struct rtentry *rt0, 389 struct mbuf *m, 390 struct sockaddr *dst, 391 u_char *desten) 392 { 393 struct rtentry *rt; 394 struct llinfo_arp *la = NULL; 395 struct sockaddr_dl *sdl; 396 397 if (m->m_flags & M_BCAST) { /* broadcast */ 398 memcpy(desten, ifp->if_broadcastaddr, ifp->if_addrlen); 399 return (1); 400 } 401 if (m->m_flags & M_MCAST && ifp->if_type != IFT_ARCNET) {/* multicast */ 402 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); 403 return (1); 404 } 405 if (rt0 != NULL) { 406 if (rt_llroute(dst, rt0, &rt) != 0) { 407 m_freem(m); 408 return 0; 409 } 410 la = rt->rt_llinfo; 411 } 412 if (la == NULL) { 413 la = arplookup(SIN(dst)->sin_addr.s_addr, TRUE, FALSE); 414 if (la != NULL) 415 rt = la->la_rt; 416 } 417 if (la == NULL || rt == NULL) { 418 log(LOG_DEBUG, "arpresolve: can't allocate llinfo for %s%s%s\n", 419 inet_ntoa(SIN(dst)->sin_addr), la ? "la" : "", 420 rt ? "rt" : ""); 421 m_freem(m); 422 return (0); 423 } 424 sdl = SDL(rt->rt_gateway); 425 /* 426 * Check the address family and length is valid, the address 427 * is resolved; otherwise, try to resolve. 428 */ 429 if ((rt->rt_expire == 0 || rt->rt_expire > time_second) && 430 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 431 /* 432 * If entry has an expiry time and it is approaching, 433 * see if we need to send an ARP request within this 434 * arpt_down interval. 435 */ 436 if ((rt->rt_expire != 0) && 437 (time_second + la->la_preempt > 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 != NULL) 464 m_freem(la->la_hold); 465 la->la_hold = m; 466 if (rt->rt_expire || ((rt->rt_flags & RTF_STATIC) && !sdl->sdl_alen)) { 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_asked = 0; 479 la->la_preempt = arp_maxtries; 480 } 481 482 } 483 } 484 return (0); 485 } 486 487 /* 488 * Common length and type checks are done here, 489 * then the protocol-specific routine is called. 490 */ 491 static int 492 arpintr(struct netmsg *msg) 493 { 494 struct mbuf *m = ((struct netmsg_packet *)msg)->nm_packet; 495 struct arphdr *ar; 496 u_short ar_hrd; 497 498 if (m->m_len < sizeof(struct arphdr) && 499 ((m = m_pullup(m, sizeof(struct arphdr))) == NULL)) { 500 log(LOG_ERR, "arp: runt packet -- m_pullup failed\n"); 501 goto out2; 502 } 503 ar = mtod(m, struct arphdr *); 504 505 ar_hrd = ntohs(ar->ar_hrd); 506 if (ar_hrd != ARPHRD_ETHER && 507 ar_hrd != ARPHRD_IEEE802 && 508 ar_hrd != ARPHRD_ARCNET) { 509 log(LOG_ERR, 510 "arp: unknown hardware address format (0x%2D)\n", 511 (unsigned char *)&ar->ar_hrd, ""); 512 goto out1; 513 } 514 515 if (m->m_pkthdr.len < arphdr_len(ar) && 516 (m = m_pullup(m, arphdr_len(ar))) == NULL) { 517 log(LOG_ERR, "arp: runt packet\n"); 518 goto out1; 519 } 520 521 switch (ntohs(ar->ar_pro)) { 522 #ifdef INET 523 case ETHERTYPE_IP: 524 in_arpinput(m); 525 goto out2; 526 #endif 527 } 528 out1: 529 m_freem(m); 530 out2: 531 lwkt_replymsg(&msg->nm_lmsg, 0); 532 return(EASYNC); 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(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 memcpy(&isaddr, ar_spa(ah), sizeof isaddr); 584 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 && myaddr.s_addr != 0) { 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), FALSE); 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, 650 "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, 661 "arp: %s moved from %*D to %*D on %s\n", 662 inet_ntoa(isaddr), 663 ifp->if_addrlen, (u_char *)LLADDR(sdl), ":", 664 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 665 ifp->if_xname); 666 else { 667 log(LOG_ERR, 668 "arp: %*D attempts to modify permanent entry for %s on %s\n", 669 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 670 inet_ntoa(isaddr), ifp->if_xname); 671 goto reply; 672 } 673 } 674 /* 675 * sanity check for the address length. 676 * XXX this does not work for protocols with variable address 677 * length. -is 678 */ 679 if (sdl->sdl_alen && 680 sdl->sdl_alen != ah->ar_hln) { 681 log(LOG_WARNING, 682 "arp from %*D: new addr len %d, was %d", 683 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 684 ah->ar_hln, sdl->sdl_alen); 685 } 686 if (ifp->if_addrlen != ah->ar_hln) { 687 log(LOG_WARNING, 688 "arp from %*D: addr len: new %d, i/f %d (ignored)", 689 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 690 ah->ar_hln, ifp->if_addrlen); 691 goto reply; 692 } 693 memcpy(LLADDR(sdl), ar_sha(ah), 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_asked = 0; 729 la->la_preempt = arp_maxtries; 730 if (la->la_hold != NULL) { 731 (*ifp->if_output)(ifp, la->la_hold, rt_key(rt), rt); 732 la->la_hold = NULL; 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 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 743 memcpy(ar_sha(ah), IF_LLADDR(ifp), ah->ar_hln); 744 } else { 745 la = arplookup(itaddr.s_addr, FALSE, 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 = rtlookup((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 --rt->rt_refcnt; 771 m_freem(m); 772 return; 773 } 774 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 775 memcpy(ar_sha(ah), IF_LLADDR(ifp), ah->ar_hln); 776 --rt->rt_refcnt; 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 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 784 sdl = SDL(rt->rt_gateway); 785 memcpy(ar_sha(ah), LLADDR(sdl), ah->ar_hln); 786 } 787 } 788 789 memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln); 790 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 memcpy(eh->ether_dhost, ar_tha(ah), sizeof(eh->ether_dhost)); 827 eh->ether_type = htons(ETHERTYPE_ARP); 828 break; 829 } 830 sa.sa_family = AF_UNSPEC; 831 sa.sa_len = sizeof(sa); 832 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 833 return; 834 } 835 #endif 836 837 /* 838 * Free an arp entry. If the arp entry is actively referenced or represents 839 * a static entry we only clear it back to an unresolved state, otherwise 840 * we destroy the entry entirely. 841 * 842 * Note that static entries are created when route add ... -interface is used 843 * to create an interface route to a (direct) destination. 844 */ 845 static void 846 arptfree(la) 847 struct llinfo_arp *la; 848 { 849 struct rtentry *rt = la->la_rt; 850 struct sockaddr_dl *sdl; 851 852 if (rt == NULL) 853 panic("arptfree"); 854 sdl = SDL(rt->rt_gateway); 855 if (sdl && ((rt->rt_refcnt > 0 && sdl->sdl_family == AF_LINK) || 856 (rt->rt_flags & RTF_STATIC))) { 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), NULL, rt_mask(rt), 0, NULL); 863 } 864 /* 865 * Lookup or enter a new address in arptab. 866 */ 867 static struct llinfo_arp * 868 arplookup(in_addr_t addr, boolean_t create, boolean_t proxy) 869 { 870 struct rtentry *rt; 871 static struct sockaddr_inarp sin = { sizeof(sin), AF_INET }; 872 const char *why = NULL; 873 874 sin.sin_addr.s_addr = addr; 875 sin.sin_other = proxy ? SIN_PROXY : 0; 876 rt = rtlookup((struct sockaddr *)&sin, create, 0UL); 877 if (rt == NULL) 878 return (NULL); 879 rt->rt_refcnt--; 880 881 if (rt->rt_flags & RTF_GATEWAY) 882 why = "host is not on local network"; 883 else if (!(rt->rt_flags & RTF_LLINFO)) 884 why = "could not allocate llinfo"; 885 else if (rt->rt_gateway->sa_family != AF_LINK) 886 why = "gateway route is not ours"; 887 888 if (why) { 889 if (create) { 890 log(LOG_DEBUG, "arplookup %s failed: %s\n", 891 inet_ntoa(sin.sin_addr), why); 892 } 893 if (rt->rt_refcnt <= 0 && (rt->rt_flags & RTF_WASCLONED)) { 894 /* No references to this route. Purge it. */ 895 rtrequest(RTM_DELETE, rt_key(rt), rt->rt_gateway, 896 rt_mask(rt), rt->rt_flags, NULL); 897 } 898 return (NULL); 899 } 900 return (rt->rt_llinfo); 901 } 902 903 void 904 arp_ifinit(struct ifnet *ifp, struct ifaddr *ifa) 905 { 906 if (IA_SIN(ifa)->sin_addr.s_addr != INADDR_ANY) 907 arprequest(ifp, &IA_SIN(ifa)->sin_addr, &IA_SIN(ifa)->sin_addr, 908 IF_LLADDR(ifp)); 909 ifa->ifa_rtrequest = arp_rtrequest; 910 ifa->ifa_flags |= RTF_CLONING; 911 } 912 913 static void 914 arp_init(void) 915 { 916 LIST_INIT(&llinfo_arp); 917 netisr_register(NETISR_ARP, cpu0_portfn, arpintr); 918 } 919 920 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0); 921