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 1.4 2003/08/07 21:54:32 dillon Exp $ 36 */ 37 38 /* 39 * Ethernet address resolution protocol. 40 * TODO: 41 * add "inuse/lock" bit (or ref. count) along with valid bit 42 */ 43 44 #include "opt_inet.h" 45 #include "opt_bdg.h" 46 47 #include <sys/param.h> 48 #include <sys/kernel.h> 49 #include <sys/queue.h> 50 #include <sys/sysctl.h> 51 #include <sys/systm.h> 52 #include <sys/mbuf.h> 53 #include <sys/malloc.h> 54 #include <sys/socket.h> 55 #include <sys/syslog.h> 56 57 #include <net/if.h> 58 #include <net/if_dl.h> 59 #include <net/if_types.h> 60 #include <net/route.h> 61 #include <net/netisr.h> 62 #include <net/if_llc.h> 63 #ifdef BRIDGE 64 #include <net/ethernet.h> 65 #include <net/bridge/bridge.h> 66 #endif 67 68 #include <netinet/in.h> 69 #include <netinet/in_var.h> 70 #include <netinet/if_ether.h> 71 72 #include <net/if_arc.h> 73 #include <net/iso88025.h> 74 75 #define SIN(s) ((struct sockaddr_in *)s) 76 #define SDL(s) ((struct sockaddr_dl *)s) 77 78 SYSCTL_DECL(_net_link_ether); 79 SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, ""); 80 81 /* timer values */ 82 static int arpt_prune = (5*60*1); /* walk list every 5 minutes */ 83 static int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */ 84 static int arpt_down = 20; /* once declared down, don't send for 20 sec */ 85 86 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, prune_intvl, CTLFLAG_RW, 87 &arpt_prune, 0, ""); 88 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW, 89 &arpt_keep, 0, ""); 90 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, host_down_time, CTLFLAG_RW, 91 &arpt_down, 0, ""); 92 93 #define rt_expire rt_rmx.rmx_expire 94 95 struct llinfo_arp { 96 LIST_ENTRY(llinfo_arp) la_le; 97 struct rtentry *la_rt; 98 struct mbuf *la_hold; /* last packet until resolved/timeout */ 99 u_short la_preempt; /* #times we QUERIED before entry expiration */ 100 u_short la_asked; /* #times we QUERIED following expiration */ 101 #define la_timer la_rt->rt_rmx.rmx_expire /* deletion time in seconds */ 102 }; 103 104 static LIST_HEAD(, llinfo_arp) llinfo_arp; 105 106 struct ifqueue arpintrq = {0, 0, 0, 50}; 107 static int arp_inuse, arp_allocated, arpinit_done; 108 109 static int arp_maxtries = 5; 110 static int useloopback = 1; /* use loopback interface for local traffic */ 111 static int arp_proxyall = 0; 112 113 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW, 114 &arp_maxtries, 0, ""); 115 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW, 116 &useloopback, 0, ""); 117 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW, 118 &arp_proxyall, 0, ""); 119 120 static void arp_rtrequest __P((int, struct rtentry *, struct rt_addrinfo *)); 121 static void arprequest __P((struct ifnet *, 122 struct in_addr *, struct in_addr *, u_char *)); 123 static void arpintr __P((void)); 124 static void arptfree __P((struct llinfo_arp *)); 125 static void arptimer __P((void *)); 126 static struct llinfo_arp 127 *arplookup __P((u_long, int, int)); 128 #ifdef INET 129 static void in_arpinput __P((struct mbuf *)); 130 #endif 131 132 u_char arcbroadcastaddr = 0; 133 134 #define IF_BCASTADDR(ifp) \ 135 ((ifp)->if_type == IFT_ARCNET ? \ 136 &arcbroadcastaddr : etherbroadcastaddr) 137 138 /* 139 * Timeout routine. Age arp_tab entries periodically. 140 */ 141 /* ARGSUSED */ 142 static void 143 arptimer(ignored_arg) 144 void *ignored_arg; 145 { 146 int s = splnet(); 147 struct llinfo_arp *la = LIST_FIRST(&llinfo_arp); 148 struct llinfo_arp *ola; 149 150 timeout(arptimer, (caddr_t)0, arpt_prune * hz); 151 while ((ola = la) != 0) { 152 struct rtentry *rt = la->la_rt; 153 la = LIST_NEXT(la, la_le); 154 if (rt->rt_expire && rt->rt_expire <= time_second) 155 arptfree(ola); /* timer has expired, clear */ 156 } 157 splx(s); 158 } 159 160 /* 161 * Parallel to llc_rtrequest. 162 */ 163 static void 164 arp_rtrequest(req, rt, info) 165 int req; 166 struct rtentry *rt; 167 struct rt_addrinfo *info; 168 { 169 struct sockaddr *gate = rt->rt_gateway; 170 struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo; 171 static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK}; 172 173 if (!arpinit_done) { 174 arpinit_done = 1; 175 timeout(arptimer, (caddr_t)0, hz); 176 } 177 if (rt->rt_flags & RTF_GATEWAY) 178 return; 179 switch (req) { 180 181 case RTM_ADD: 182 /* 183 * XXX: If this is a manually added route to interface 184 * such as older version of routed or gated might provide, 185 * restore cloning bit. 186 */ 187 if ((rt->rt_flags & RTF_HOST) == 0 && 188 SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff) 189 rt->rt_flags |= RTF_CLONING; 190 if (rt->rt_flags & RTF_CLONING) { 191 /* 192 * Case 1: This route should come from a route to iface. 193 */ 194 rt_setgate(rt, rt_key(rt), 195 (struct sockaddr *)&null_sdl); 196 gate = rt->rt_gateway; 197 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 198 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 199 rt->rt_expire = time_second; 200 break; 201 } 202 /* Announce a new entry if requested. */ 203 if (rt->rt_flags & RTF_ANNOUNCE) 204 arprequest(rt->rt_ifp, 205 &SIN(rt_key(rt))->sin_addr, 206 &SIN(rt_key(rt))->sin_addr, 207 (u_char *)LLADDR(SDL(gate))); 208 /*FALLTHROUGH*/ 209 case RTM_RESOLVE: 210 if (gate->sa_family != AF_LINK || 211 gate->sa_len < sizeof(null_sdl)) { 212 log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n"); 213 break; 214 } 215 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 216 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 217 if (la != 0) 218 break; /* This happens on a route change */ 219 /* 220 * Case 2: This route may come from cloning, or a manual route 221 * add with a LL address. 222 */ 223 R_Malloc(la, struct llinfo_arp *, sizeof(*la)); 224 rt->rt_llinfo = (caddr_t)la; 225 if (la == 0) { 226 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); 227 break; 228 } 229 arp_inuse++, arp_allocated++; 230 Bzero(la, sizeof(*la)); 231 la->la_rt = rt; 232 rt->rt_flags |= RTF_LLINFO; 233 LIST_INSERT_HEAD(&llinfo_arp, la, la_le); 234 235 #ifdef INET 236 /* 237 * This keeps the multicast addresses from showing up 238 * in `arp -a' listings as unresolved. It's not actually 239 * functional. Then the same for broadcast. 240 */ 241 if (IN_MULTICAST(ntohl(SIN(rt_key(rt))->sin_addr.s_addr)) 242 && rt->rt_ifp->if_type != IFT_ARCNET) { 243 ETHER_MAP_IP_MULTICAST(&SIN(rt_key(rt))->sin_addr, 244 LLADDR(SDL(gate))); 245 SDL(gate)->sdl_alen = 6; 246 rt->rt_expire = 0; 247 } 248 if (in_broadcast(SIN(rt_key(rt))->sin_addr, rt->rt_ifp)) { 249 memcpy(LLADDR(SDL(gate)), IF_BCASTADDR(rt->rt_ifp), 250 rt->rt_ifp->if_addrlen); 251 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen; 252 rt->rt_expire = 0; 253 } 254 #endif 255 256 if (SIN(rt_key(rt))->sin_addr.s_addr == 257 (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) { 258 /* 259 * This test used to be 260 * if (loif.if_flags & IFF_UP) 261 * It allowed local traffic to be forced 262 * through the hardware by configuring the loopback down. 263 * However, it causes problems during network configuration 264 * for boards that can't receive packets they send. 265 * It is now necessary to clear "useloopback" and remove 266 * the route to force traffic out to the hardware. 267 */ 268 rt->rt_expire = 0; 269 Bcopy(IF_LLADDR(rt->rt_ifp), LLADDR(SDL(gate)), 270 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen); 271 if (useloopback) 272 rt->rt_ifp = loif; 273 274 } 275 break; 276 277 case RTM_DELETE: 278 if (la == 0) 279 break; 280 arp_inuse--; 281 LIST_REMOVE(la, la_le); 282 rt->rt_llinfo = 0; 283 rt->rt_flags &= ~RTF_LLINFO; 284 if (la->la_hold) 285 m_freem(la->la_hold); 286 Free((caddr_t)la); 287 } 288 } 289 290 /* 291 * Broadcast an ARP request. Caller specifies: 292 * - arp header source ip address 293 * - arp header target ip address 294 * - arp header source ethernet address 295 */ 296 static void 297 arprequest(ifp, sip, tip, enaddr) 298 struct ifnet *ifp; 299 struct in_addr *sip, *tip; 300 u_char *enaddr; 301 { 302 struct mbuf *m; 303 struct ether_header *eh; 304 struct arc_header *arh; 305 struct arphdr *ah; 306 struct sockaddr sa; 307 static u_char llcx[] = { 0x82, 0x40, LLC_SNAP_LSAP, LLC_SNAP_LSAP, 308 LLC_UI, 0x00, 0x00, 0x00, 0x08, 0x06 }; 309 u_short ar_hrd; 310 311 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 312 return; 313 m->m_pkthdr.rcvif = (struct ifnet *)0; 314 switch (ifp->if_type) { 315 case IFT_ARCNET: 316 ar_hrd = htons(ARPHRD_ARCNET); 317 318 m->m_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 319 m->m_pkthdr.len = m->m_len; 320 MH_ALIGN(m, m->m_len); 321 322 arh = (struct arc_header *)sa.sa_data; 323 arh->arc_dhost = arcbroadcastaddr; 324 arh->arc_type = ARCTYPE_ARP; 325 326 ah = mtod(m, struct arphdr *); 327 break; 328 329 case IFT_ISO88025: 330 ar_hrd = htons(ARPHRD_IEEE802); 331 332 m->m_len = sizeof(llcx) + 333 arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 334 m->m_pkthdr.len = m->m_len; 335 MH_ALIGN(m, m->m_len); 336 337 (void)memcpy(mtod(m, caddr_t), llcx, sizeof(llcx)); 338 (void)memcpy(sa.sa_data, etherbroadcastaddr, 6); 339 (void)memcpy(sa.sa_data + 6, enaddr, 6); 340 sa.sa_data[6] |= TR_RII; 341 sa.sa_data[12] = TR_AC; 342 sa.sa_data[13] = TR_LLC_FRAME; 343 344 ah = (struct arphdr *)(mtod(m, char *) + sizeof(llcx)); 345 break; 346 case IFT_FDDI: 347 case IFT_ETHER: 348 /* 349 * This may not be correct for types not explicitly 350 * listed, but this is our best guess 351 */ 352 default: 353 ar_hrd = htons(ARPHRD_ETHER); 354 355 m->m_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 356 m->m_pkthdr.len = m->m_len; 357 MH_ALIGN(m, m->m_len); 358 359 eh = (struct ether_header *)sa.sa_data; 360 /* if_output will not swap */ 361 eh->ether_type = htons(ETHERTYPE_ARP); 362 (void)memcpy(eh->ether_dhost, etherbroadcastaddr, 363 sizeof(eh->ether_dhost)); 364 365 ah = mtod(m, struct arphdr *); 366 break; 367 } 368 369 ah->ar_hrd = ar_hrd; 370 ah->ar_pro = htons(ETHERTYPE_IP); 371 ah->ar_hln = ifp->if_addrlen; /* hardware address length */ 372 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 373 ah->ar_op = htons(ARPOP_REQUEST); 374 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln); 375 memset(ar_tha(ah), 0, ah->ar_hln); 376 (void)memcpy(ar_spa(ah), sip, ah->ar_pln); 377 (void)memcpy(ar_tpa(ah), tip, ah->ar_pln); 378 379 sa.sa_family = AF_UNSPEC; 380 sa.sa_len = sizeof(sa); 381 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 382 } 383 384 /* 385 * Resolve an IP address into an ethernet address. If success, 386 * desten is filled in. If there is no entry in arptab, 387 * set one up and broadcast a request for the IP address. 388 * Hold onto this mbuf and resend it once the address 389 * is finally resolved. A return value of 1 indicates 390 * that desten has been filled in and the packet should be sent 391 * normally; a 0 return indicates that the packet has been 392 * taken over here, either now or for later transmission. 393 */ 394 int 395 arpresolve(ifp, rt, m, dst, desten, rt0) 396 struct ifnet *ifp; 397 struct rtentry *rt; 398 struct mbuf *m; 399 struct sockaddr *dst; 400 u_char *desten; 401 struct rtentry *rt0; 402 { 403 struct llinfo_arp *la = 0; 404 struct sockaddr_dl *sdl; 405 406 if (m->m_flags & M_BCAST) { /* broadcast */ 407 (void)memcpy(desten, IF_BCASTADDR(ifp), ifp->if_addrlen); 408 return (1); 409 } 410 if (m->m_flags & M_MCAST && ifp->if_type != IFT_ARCNET) {/* multicast */ 411 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); 412 return(1); 413 } 414 if (rt) 415 la = (struct llinfo_arp *)rt->rt_llinfo; 416 if (la == 0) { 417 la = arplookup(SIN(dst)->sin_addr.s_addr, 1, 0); 418 if (la) 419 rt = la->la_rt; 420 } 421 if (la == 0 || rt == 0) { 422 log(LOG_DEBUG, "arpresolve: can't allocate llinfo for %s%s%s\n", 423 inet_ntoa(SIN(dst)->sin_addr), la ? "la" : "", 424 rt ? "rt" : ""); 425 m_freem(m); 426 return (0); 427 } 428 sdl = SDL(rt->rt_gateway); 429 /* 430 * Check the address family and length is valid, the address 431 * is resolved; otherwise, try to resolve. 432 */ 433 if ((rt->rt_expire == 0 || rt->rt_expire > time_second) && 434 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 435 /* 436 * If entry has an expiry time and it is approaching, 437 * see if we need to send an ARP request within this 438 * arpt_down interval. 439 */ 440 if ((rt->rt_expire != 0) && 441 (time_second + (arp_maxtries - la->la_preempt) * arpt_down 442 > rt->rt_expire)) { 443 arprequest(ifp, 444 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 445 &SIN(dst)->sin_addr, 446 IF_LLADDR(ifp)); 447 la->la_preempt++; 448 } 449 450 bcopy(LLADDR(sdl), desten, sdl->sdl_alen); 451 return 1; 452 } 453 /* 454 * If ARP is disabled on this interface, stop. 455 * XXX 456 * Probably should not allocate empty llinfo struct if we are 457 * not going to be sending out an arp request. 458 */ 459 if (ifp->if_flags & IFF_NOARP) { 460 m_freem(m); 461 return (0); 462 } 463 /* 464 * There is an arptab entry, but no ethernet address 465 * response yet. Replace the held mbuf with this 466 * latest one. 467 */ 468 if (la->la_hold) 469 m_freem(la->la_hold); 470 la->la_hold = m; 471 if (rt->rt_expire) { 472 rt->rt_flags &= ~RTF_REJECT; 473 if (la->la_asked == 0 || rt->rt_expire != time_second) { 474 rt->rt_expire = time_second; 475 if (la->la_asked++ < arp_maxtries) { 476 arprequest(ifp, 477 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 478 &SIN(dst)->sin_addr, 479 IF_LLADDR(ifp)); 480 } else { 481 rt->rt_flags |= RTF_REJECT; 482 rt->rt_expire += arpt_down; 483 la->la_preempt = la->la_asked = 0; 484 } 485 486 } 487 } 488 return (0); 489 } 490 491 /* 492 * Common length and type checks are done here, 493 * then the protocol-specific routine is called. 494 */ 495 static void 496 arpintr() 497 { 498 struct mbuf *m; 499 struct arphdr *ar; 500 int s; 501 502 while (arpintrq.ifq_head) { 503 s = splimp(); 504 IF_DEQUEUE(&arpintrq, m); 505 splx(s); 506 if (m == 0 || (m->m_flags & M_PKTHDR) == 0) 507 panic("arpintr"); 508 509 if (m->m_len < sizeof(struct arphdr) && 510 ((m = m_pullup(m, sizeof(struct arphdr))) == NULL)) { 511 log(LOG_ERR, "arp: runt packet -- m_pullup failed\n"); 512 continue; 513 } 514 ar = mtod(m, struct arphdr *); 515 516 if (ntohs(ar->ar_hrd) != ARPHRD_ETHER 517 && ntohs(ar->ar_hrd) != ARPHRD_IEEE802 518 && ntohs(ar->ar_hrd) != ARPHRD_ARCNET) { 519 log(LOG_ERR, 520 "arp: unknown hardware address format (0x%2D)\n", 521 (unsigned char *)&ar->ar_hrd, ""); 522 m_freem(m); 523 continue; 524 } 525 526 if (m->m_pkthdr.len < arphdr_len(ar) && 527 (m = m_pullup(m, arphdr_len(ar))) == NULL) { 528 log(LOG_ERR, "arp: runt packet\n"); 529 m_freem(m); 530 continue; 531 } 532 533 switch (ntohs(ar->ar_pro)) { 534 #ifdef INET 535 case ETHERTYPE_IP: 536 in_arpinput(m); 537 continue; 538 #endif 539 } 540 m_freem(m); 541 } 542 } 543 544 #ifdef INET 545 /* 546 * ARP for Internet protocols on 10 Mb/s Ethernet. 547 * Algorithm is that given in RFC 826. 548 * In addition, a sanity check is performed on the sender 549 * protocol address, to catch impersonators. 550 * We no longer handle negotiations for use of trailer protocol: 551 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 552 * along with IP replies if we wanted trailers sent to us, 553 * and also sent them in response to IP replies. 554 * This allowed either end to announce the desire to receive 555 * trailer packets. 556 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 557 * but formerly didn't normally send requests. 558 */ 559 static int log_arp_wrong_iface = 1; 560 561 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW, 562 &log_arp_wrong_iface, 0, 563 "log arp packets arriving on the wrong interface"); 564 565 static void 566 in_arpinput(m) 567 struct mbuf *m; 568 { 569 struct arphdr *ah; 570 struct ifnet *ifp = m->m_pkthdr.rcvif; 571 struct ether_header *eh; 572 struct arc_header *arh; 573 struct iso88025_header *th = (struct iso88025_header *)0; 574 struct iso88025_sockaddr_dl_data *trld; 575 struct llinfo_arp *la = 0; 576 struct rtentry *rt; 577 struct ifaddr *ifa; 578 struct in_ifaddr *ia; 579 struct sockaddr_dl *sdl; 580 struct sockaddr sa; 581 struct in_addr isaddr, itaddr, myaddr; 582 int op, rif_len; 583 int req_len; 584 585 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 586 if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) { 587 log(LOG_ERR, "in_arp: runt packet -- m_pullup failed\n"); 588 return; 589 } 590 591 ah = mtod(m, struct arphdr *); 592 op = ntohs(ah->ar_op); 593 (void)memcpy(&isaddr, ar_spa(ah), sizeof (isaddr)); 594 (void)memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr)); 595 #ifdef BRIDGE 596 #define BRIDGE_TEST (do_bridge) 597 #else 598 #define BRIDGE_TEST (0) /* cc will optimise the test away */ 599 #endif 600 /* 601 * For a bridge, we want to check the address irrespective 602 * of the receive interface. (This will change slightly 603 * when we have clusters of interfaces). 604 */ 605 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) 606 if ((BRIDGE_TEST || (ia->ia_ifp == ifp)) && 607 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) 608 goto match; 609 LIST_FOREACH(ia, INADDR_HASH(isaddr.s_addr), ia_hash) 610 if ((BRIDGE_TEST || (ia->ia_ifp == ifp)) && 611 isaddr.s_addr == ia->ia_addr.sin_addr.s_addr) 612 goto match; 613 /* 614 * No match, use the first inet address on the receive interface 615 * as a dummy address for the rest of the function. 616 */ 617 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) 618 if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_INET) { 619 ia = ifatoia(ifa); 620 goto match; 621 } 622 /* 623 * If bridging, fall back to using any inet address. 624 * This is probably incorrect, the right way being try to match 625 * addresses for interfaces in the same cluster, so if we 626 * get here we should always drop the packet. 627 */ 628 if (!BRIDGE_TEST || 629 (ia = TAILQ_FIRST(&in_ifaddrhead)) == NULL) { 630 m_freem(m); 631 return; 632 } 633 match: 634 myaddr = ia->ia_addr.sin_addr; 635 if (!bcmp(ar_sha(ah), IF_LLADDR(ifp), ifp->if_addrlen)) { 636 m_freem(m); /* it's from me, ignore it. */ 637 return; 638 } 639 if (!bcmp(ar_sha(ah), IF_BCASTADDR(ifp), ifp->if_addrlen)) { 640 log(LOG_ERR, 641 "arp: link address is broadcast for IP address %s!\n", 642 inet_ntoa(isaddr)); 643 m_freem(m); 644 return; 645 } 646 if (isaddr.s_addr == myaddr.s_addr) { 647 log(LOG_ERR, 648 "arp: %*D is using my IP address %s!\n", 649 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 650 inet_ntoa(isaddr)); 651 itaddr = myaddr; 652 goto reply; 653 } 654 la = arplookup(isaddr.s_addr, itaddr.s_addr == myaddr.s_addr, 0); 655 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { 656 /* the following is not an error when doing bridging */ 657 if (!BRIDGE_TEST && rt->rt_ifp != ifp) { 658 if (log_arp_wrong_iface) 659 log(LOG_ERR, "arp: %s is on %s%d but got reply from %*D on %s%d\n", 660 inet_ntoa(isaddr), 661 rt->rt_ifp->if_name, rt->rt_ifp->if_unit, 662 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 663 ifp->if_name, ifp->if_unit); 664 goto reply; 665 } 666 if (sdl->sdl_alen && 667 bcmp(ar_sha(ah), LLADDR(sdl), sdl->sdl_alen)) { 668 if (rt->rt_expire) 669 log(LOG_INFO, "arp: %s moved from %*D to %*D on %s%d\n", 670 inet_ntoa(isaddr), 671 ifp->if_addrlen, (u_char *)LLADDR(sdl), ":", 672 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 673 ifp->if_name, ifp->if_unit); 674 else { 675 log(LOG_ERR, 676 "arp: %*D attempts to modify permanent entry for %s on %s%d\n", 677 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 678 inet_ntoa(isaddr), ifp->if_name, ifp->if_unit); 679 goto reply; 680 } 681 } 682 /* 683 * sanity check for the address length. 684 * XXX this does not work for protocols with variable address 685 * length. -is 686 */ 687 if (sdl->sdl_alen && 688 sdl->sdl_alen != ah->ar_hln) { 689 log(LOG_WARNING, 690 "arp from %*D: new addr len %d, was %d", 691 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 692 ah->ar_hln, sdl->sdl_alen); 693 } 694 if (ifp->if_addrlen != ah->ar_hln) { 695 log(LOG_WARNING, 696 "arp from %*D: addr len: new %d, i/f %d (ignored)", 697 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 698 ah->ar_hln, ifp->if_addrlen); 699 goto reply; 700 } 701 (void)memcpy(LLADDR(sdl), ar_sha(ah), 702 sdl->sdl_alen = ah->ar_hln); 703 /* 704 * If we receive an arp from a token-ring station over 705 * a token-ring nic then try to save the source 706 * routing info. 707 */ 708 if (ifp->if_type == IFT_ISO88025) { 709 th = (struct iso88025_header *)m->m_pkthdr.header; 710 trld = SDL_ISO88025(sdl); 711 rif_len = TR_RCF_RIFLEN(th->rcf); 712 if ((th->iso88025_shost[0] & TR_RII) && 713 (rif_len > 2)) { 714 trld->trld_rcf = th->rcf; 715 trld->trld_rcf ^= htons(TR_RCF_DIR); 716 memcpy(trld->trld_route, th->rd, rif_len - 2); 717 trld->trld_rcf &= ~htons(TR_RCF_BCST_MASK); 718 /* 719 * Set up source routing information for 720 * reply packet (XXX) 721 */ 722 m->m_data -= rif_len; 723 m->m_len += rif_len; 724 m->m_pkthdr.len += rif_len; 725 } else { 726 th->iso88025_shost[0] &= ~TR_RII; 727 trld->trld_rcf = 0; 728 } 729 m->m_data -= 8; 730 m->m_len += 8; 731 m->m_pkthdr.len += 8; 732 th->rcf = trld->trld_rcf; 733 } 734 if (rt->rt_expire) 735 rt->rt_expire = time_second + arpt_keep; 736 rt->rt_flags &= ~RTF_REJECT; 737 la->la_preempt = la->la_asked = 0; 738 if (la->la_hold) { 739 (*ifp->if_output)(ifp, la->la_hold, 740 rt_key(rt), rt); 741 la->la_hold = 0; 742 } 743 } 744 reply: 745 if (op != ARPOP_REQUEST) { 746 m_freem(m); 747 return; 748 } 749 if (itaddr.s_addr == myaddr.s_addr) { 750 /* I am the target */ 751 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 752 (void)memcpy(ar_sha(ah), IF_LLADDR(ifp), ah->ar_hln); 753 } else { 754 la = arplookup(itaddr.s_addr, 0, SIN_PROXY); 755 if (la == NULL) { 756 struct sockaddr_in sin; 757 758 if (!arp_proxyall) { 759 m_freem(m); 760 return; 761 } 762 763 bzero(&sin, sizeof sin); 764 sin.sin_family = AF_INET; 765 sin.sin_len = sizeof sin; 766 sin.sin_addr = itaddr; 767 768 rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL); 769 if (!rt) { 770 m_freem(m); 771 return; 772 } 773 /* 774 * Don't send proxies for nodes on the same interface 775 * as this one came out of, or we'll get into a fight 776 * over who claims what Ether address. 777 */ 778 if (rt->rt_ifp == ifp) { 779 rtfree(rt); 780 m_freem(m); 781 return; 782 } 783 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 784 (void)memcpy(ar_sha(ah), IF_LLADDR(ifp), ah->ar_hln); 785 rtfree(rt); 786 #ifdef DEBUG_PROXY 787 printf("arp: proxying for %s\n", 788 inet_ntoa(itaddr)); 789 #endif 790 } else { 791 rt = la->la_rt; 792 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 793 sdl = SDL(rt->rt_gateway); 794 (void)memcpy(ar_sha(ah), LLADDR(sdl), ah->ar_hln); 795 } 796 } 797 798 (void)memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln); 799 (void)memcpy(ar_spa(ah), &itaddr, ah->ar_pln); 800 ah->ar_op = htons(ARPOP_REPLY); 801 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 802 switch (ifp->if_type) { 803 case IFT_ARCNET: 804 arh = (struct arc_header *)sa.sa_data; 805 arh->arc_dhost = *ar_tha(ah); 806 arh->arc_type = ARCTYPE_ARP; 807 break; 808 809 case IFT_ISO88025: 810 /* Re-arrange the source/dest address */ 811 memcpy(th->iso88025_dhost, th->iso88025_shost, 812 sizeof(th->iso88025_dhost)); 813 memcpy(th->iso88025_shost, IF_LLADDR(ifp), 814 sizeof(th->iso88025_shost)); 815 /* Set the source routing bit if neccesary */ 816 if (th->iso88025_dhost[0] & TR_RII) { 817 th->iso88025_dhost[0] &= ~TR_RII; 818 if (TR_RCF_RIFLEN(th->rcf) > 2) 819 th->iso88025_shost[0] |= TR_RII; 820 } 821 /* Copy the addresses, ac and fc into sa_data */ 822 memcpy(sa.sa_data, th->iso88025_dhost, 823 sizeof(th->iso88025_dhost) * 2); 824 sa.sa_data[(sizeof(th->iso88025_dhost) * 2)] = TR_AC; 825 sa.sa_data[(sizeof(th->iso88025_dhost) * 2) + 1] = TR_LLC_FRAME; 826 break; 827 case IFT_ETHER: 828 case IFT_FDDI: 829 /* 830 * May not be correct for types not explictly 831 * listed, but it is our best guess. 832 */ 833 default: 834 eh = (struct ether_header *)sa.sa_data; 835 (void)memcpy(eh->ether_dhost, ar_tha(ah), 836 sizeof(eh->ether_dhost)); 837 eh->ether_type = htons(ETHERTYPE_ARP); 838 break; 839 } 840 sa.sa_family = AF_UNSPEC; 841 sa.sa_len = sizeof(sa); 842 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 843 return; 844 } 845 #endif 846 847 /* 848 * Free an arp entry. 849 */ 850 static void 851 arptfree(la) 852 struct llinfo_arp *la; 853 { 854 struct rtentry *rt = la->la_rt; 855 struct sockaddr_dl *sdl; 856 if (rt == 0) 857 panic("arptfree"); 858 if (rt->rt_refcnt > 0 && (sdl = SDL(rt->rt_gateway)) && 859 sdl->sdl_family == AF_LINK) { 860 sdl->sdl_alen = 0; 861 la->la_preempt = la->la_asked = 0; 862 rt->rt_flags &= ~RTF_REJECT; 863 return; 864 } 865 rtrequest(RTM_DELETE, rt_key(rt), (struct sockaddr *)0, rt_mask(rt), 866 0, (struct rtentry **)0); 867 } 868 /* 869 * Lookup or enter a new address in arptab. 870 */ 871 static struct llinfo_arp * 872 arplookup(addr, create, proxy) 873 u_long addr; 874 int create, proxy; 875 { 876 struct rtentry *rt; 877 static struct sockaddr_inarp sin = {sizeof(sin), AF_INET }; 878 const char *why = 0; 879 880 sin.sin_addr.s_addr = addr; 881 sin.sin_other = proxy ? SIN_PROXY : 0; 882 rt = rtalloc1((struct sockaddr *)&sin, create, 0UL); 883 if (rt == 0) 884 return (0); 885 rt->rt_refcnt--; 886 887 if (rt->rt_flags & RTF_GATEWAY) 888 why = "host is not on local network"; 889 else if ((rt->rt_flags & RTF_LLINFO) == 0) 890 why = "could not allocate llinfo"; 891 else if (rt->rt_gateway->sa_family != AF_LINK) 892 why = "gateway route is not ours"; 893 894 if (why && create) { 895 log(LOG_DEBUG, "arplookup %s failed: %s\n", 896 inet_ntoa(sin.sin_addr), why); 897 return 0; 898 } else if (why) { 899 return 0; 900 } 901 return ((struct llinfo_arp *)rt->rt_llinfo); 902 } 903 904 void 905 arp_ifinit(ifp, ifa) 906 struct ifnet *ifp; 907 struct ifaddr *ifa; 908 { 909 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY) 910 arprequest(ifp, &IA_SIN(ifa)->sin_addr, 911 &IA_SIN(ifa)->sin_addr, IF_LLADDR(ifp)); 912 ifa->ifa_rtrequest = arp_rtrequest; 913 ifa->ifa_flags |= RTF_CLONING; 914 } 915 916 static void 917 arp_init(void) 918 { 919 LIST_INIT(&llinfo_arp); 920 register_netisr(NETISR_ARP, arpintr); 921 } 922 923 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0); 924