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sys/netinet/if_ether.c
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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: releng/5.1/sys/netinet/if_ether.c 120420 2003-09-24 21:51:13Z bms $ 35 */ 36 37 /* 38 * Ethernet address resolution protocol. 39 * TODO: 40 * add "inuse/lock" bit (or ref. count) along with valid bit 41 */ 42 43 #include "opt_inet.h" 44 #include "opt_bdg.h" 45 #include "opt_mac.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/mac.h> 53 #include <sys/mbuf.h> 54 #include <sys/malloc.h> 55 #include <sys/socket.h> 56 #include <sys/syslog.h> 57 58 #include <net/if.h> 59 #include <net/if_dl.h> 60 #include <net/if_types.h> 61 #include <net/route.h> 62 #include <net/netisr.h> 63 #include <net/if_llc.h> 64 #ifdef BRIDGE 65 #include <net/ethernet.h> 66 #include <net/bridge.h> 67 #endif 68 69 #include <netinet/in.h> 70 #include <netinet/in_var.h> 71 #include <netinet/if_ether.h> 72 73 #include <net/if_arc.h> 74 #include <net/iso88025.h> 75 76 #define SIN(s) ((struct sockaddr_in *)s) 77 #define SDL(s) ((struct sockaddr_dl *)s) 78 79 SYSCTL_DECL(_net_link_ether); 80 SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, ""); 81 82 /* timer values */ 83 static int arpt_prune = (5*60*1); /* walk list every 5 minutes */ 84 static int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */ 85 static int arpt_down = 20; /* once declared down, don't send for 20 sec */ 86 87 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, prune_intvl, CTLFLAG_RW, 88 &arpt_prune, 0, ""); 89 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW, 90 &arpt_keep, 0, ""); 91 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, host_down_time, CTLFLAG_RW, 92 &arpt_down, 0, ""); 93 94 #define rt_expire rt_rmx.rmx_expire 95 96 struct llinfo_arp { 97 LIST_ENTRY(llinfo_arp) la_le; 98 struct rtentry *la_rt; 99 struct mbuf *la_hold; /* last packet until resolved/timeout */ 100 u_short la_preempt; /* countdown for pre-expiry arps */ 101 u_short la_asked; /* #times we QUERIED following expiration */ 102 #define la_timer la_rt->rt_rmx.rmx_expire /* deletion time in seconds */ 103 }; 104 105 static LIST_HEAD(, llinfo_arp) llinfo_arp; 106 107 static struct ifqueue arpintrq; 108 static int arp_inuse, arp_allocated, arpinit_done; 109 110 static int arp_maxtries = 5; 111 static int useloopback = 1; /* use loopback interface for local traffic */ 112 static int arp_proxyall = 0; 113 114 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW, 115 &arp_maxtries, 0, ""); 116 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW, 117 &useloopback, 0, ""); 118 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW, 119 &arp_proxyall, 0, ""); 120 121 static void arp_init(void); 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 void arpintr(struct mbuf *); 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 struct llinfo_arp *la, *ola; 143 int s = splnet(); 144 145 RADIX_NODE_HEAD_LOCK(rt_tables[AF_INET]); 146 la = LIST_FIRST(&llinfo_arp); 147 while (la != NULL) { 148 struct rtentry *rt = la->la_rt; 149 ola = la; 150 la = LIST_NEXT(la, la_le); 151 if (rt->rt_expire && rt->rt_expire <= time_second) 152 arptfree(ola); /* timer has expired, clear */ 153 } 154 RADIX_NODE_HEAD_UNLOCK(rt_tables[AF_INET]); 155 splx(s); 156 timeout(arptimer, NULL, arpt_prune * hz); 157 } 158 159 /* 160 * Parallel to llc_rtrequest. 161 */ 162 static void 163 arp_rtrequest(req, rt, info) 164 int req; 165 register struct rtentry *rt; 166 struct rt_addrinfo *info; 167 { 168 register struct sockaddr *gate = rt->rt_gateway; 169 register struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo; 170 static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK}; 171 172 if (!arpinit_done) { 173 arpinit_done = 1; 174 timeout(arptimer, (caddr_t)0, hz); 175 } 176 if (rt->rt_flags & RTF_GATEWAY) 177 return; 178 switch (req) { 179 180 case RTM_ADD: 181 /* 182 * XXX: If this is a manually added route to interface 183 * such as older version of routed or gated might provide, 184 * restore cloning bit. 185 */ 186 if ((rt->rt_flags & RTF_HOST) == 0 && 187 SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff) 188 rt->rt_flags |= RTF_CLONING; 189 if (rt->rt_flags & RTF_CLONING) { 190 /* 191 * Case 1: This route should come from a route to iface. 192 */ 193 rt_setgate(rt, rt_key(rt), 194 (struct sockaddr *)&null_sdl); 195 gate = rt->rt_gateway; 196 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 197 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 198 rt->rt_expire = time_second; 199 break; 200 } 201 /* Announce a new entry if requested. */ 202 if (rt->rt_flags & RTF_ANNOUNCE) 203 arprequest(rt->rt_ifp, 204 &SIN(rt_key(rt))->sin_addr, 205 &SIN(rt_key(rt))->sin_addr, 206 (u_char *)LLADDR(SDL(gate))); 207 /*FALLTHROUGH*/ 208 case RTM_RESOLVE: 209 if (gate->sa_family != AF_LINK || 210 gate->sa_len < sizeof(null_sdl)) { 211 log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n"); 212 break; 213 } 214 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 215 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 216 if (la != 0) 217 break; /* This happens on a route change */ 218 /* 219 * Case 2: This route may come from cloning, or a manual route 220 * add with a LL address. 221 */ 222 R_Malloc(la, struct llinfo_arp *, sizeof(*la)); 223 rt->rt_llinfo = (caddr_t)la; 224 if (la == 0) { 225 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); 226 break; 227 } 228 arp_inuse++, arp_allocated++; 229 Bzero(la, sizeof(*la)); 230 la->la_rt = rt; 231 rt->rt_flags |= RTF_LLINFO; 232 RADIX_NODE_HEAD_LOCK_ASSERT(rt_tables[AF_INET]); 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)), rt->rt_ifp->if_broadcastaddr, 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 RADIX_NODE_HEAD_LOCK_ASSERT(rt_tables[AF_INET]); 282 LIST_REMOVE(la, la_le); 283 rt->rt_llinfo = 0; 284 rt->rt_flags &= ~RTF_LLINFO; 285 if (la->la_hold) 286 m_freem(la->la_hold); 287 Free((caddr_t)la); 288 } 289 } 290 291 /* 292 * Broadcast an ARP request. Caller specifies: 293 * - arp header source ip address 294 * - arp header target ip address 295 * - arp header source ethernet address 296 */ 297 static void 298 arprequest(ifp, sip, tip, enaddr) 299 register struct ifnet *ifp; 300 register struct in_addr *sip, *tip; 301 register u_char *enaddr; 302 { 303 register struct mbuf *m; 304 register struct ether_header *eh; 305 register struct arc_header *arh; 306 register struct arphdr *ah; 307 struct sockaddr sa; 308 static u_char llcx[] = { 0x82, 0x40, LLC_SNAP_LSAP, LLC_SNAP_LSAP, 309 LLC_UI, 0x00, 0x00, 0x00, 0x08, 0x06 }; 310 u_short ar_hrd; 311 312 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 313 return; 314 m->m_pkthdr.rcvif = (struct ifnet *)0; 315 #ifdef MAC 316 mac_create_mbuf_linklayer(ifp, m); 317 #endif 318 switch (ifp->if_type) { 319 case IFT_ARCNET: 320 ar_hrd = htons(ARPHRD_ARCNET); 321 322 m->m_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 323 m->m_pkthdr.len = m->m_len; 324 MH_ALIGN(m, m->m_len); 325 326 arh = (struct arc_header *)sa.sa_data; 327 arh->arc_dhost = *ifp->if_broadcastaddr; 328 arh->arc_type = ARCTYPE_ARP; 329 330 ah = mtod(m, struct arphdr *); 331 break; 332 333 case IFT_ISO88025: 334 ar_hrd = htons(ARPHRD_IEEE802); 335 336 m->m_len = sizeof(llcx) + 337 arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 338 m->m_pkthdr.len = m->m_len; 339 MH_ALIGN(m, m->m_len); 340 341 (void)memcpy(mtod(m, caddr_t), llcx, sizeof(llcx)); 342 (void)memcpy(sa.sa_data, ifp->if_broadcastaddr, 6); 343 (void)memcpy(sa.sa_data + 6, enaddr, 6); 344 sa.sa_data[6] |= TR_RII; 345 sa.sa_data[12] = TR_AC; 346 sa.sa_data[13] = TR_LLC_FRAME; 347 348 ah = (struct arphdr *)(mtod(m, char *) + sizeof(llcx)); 349 break; 350 case IFT_FDDI: 351 case IFT_ETHER: 352 /* 353 * This may not be correct for types not explicitly 354 * listed, but this is our best guess 355 */ 356 default: 357 ar_hrd = htons(ARPHRD_ETHER); 358 359 m->m_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 360 m->m_pkthdr.len = m->m_len; 361 MH_ALIGN(m, m->m_len); 362 363 eh = (struct ether_header *)sa.sa_data; 364 /* if_output will not swap */ 365 eh->ether_type = htons(ETHERTYPE_ARP); 366 (void)memcpy(eh->ether_dhost, ifp->if_broadcastaddr, 367 sizeof(eh->ether_dhost)); 368 369 ah = mtod(m, struct arphdr *); 370 break; 371 } 372 373 ah->ar_hrd = ar_hrd; 374 ah->ar_pro = htons(ETHERTYPE_IP); 375 ah->ar_hln = ifp->if_addrlen; /* hardware address length */ 376 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 377 ah->ar_op = htons(ARPOP_REQUEST); 378 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln); 379 memset(ar_tha(ah), 0, ah->ar_hln); 380 (void)memcpy(ar_spa(ah), sip, ah->ar_pln); 381 (void)memcpy(ar_tpa(ah), tip, ah->ar_pln); 382 383 sa.sa_family = AF_UNSPEC; 384 sa.sa_len = sizeof(sa); 385 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 386 } 387 388 /* 389 * Resolve an IP address into an ethernet address. If success, 390 * desten is filled in. If there is no entry in arptab, 391 * set one up and broadcast a request for the IP address. 392 * Hold onto this mbuf and resend it once the address 393 * is finally resolved. A return value of 1 indicates 394 * that desten has been filled in and the packet should be sent 395 * normally; a 0 return indicates that the packet has been 396 * taken over here, either now or for later transmission. 397 */ 398 int 399 arpresolve(ifp, rt, m, dst, desten, rt0) 400 register struct ifnet *ifp; 401 register struct rtentry *rt; 402 struct mbuf *m; 403 register struct sockaddr *dst; 404 register u_char *desten; 405 struct rtentry *rt0; 406 { 407 struct llinfo_arp *la = 0; 408 struct sockaddr_dl *sdl; 409 410 if (m->m_flags & M_BCAST) { /* broadcast */ 411 (void)memcpy(desten, ifp->if_broadcastaddr, ifp->if_addrlen); 412 return (1); 413 } 414 if (m->m_flags & M_MCAST && ifp->if_type != IFT_ARCNET) {/* multicast */ 415 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); 416 return(1); 417 } 418 if (rt) 419 la = (struct llinfo_arp *)rt->rt_llinfo; 420 if (la == 0) { 421 la = arplookup(SIN(dst)->sin_addr.s_addr, 1, 0); 422 if (la) 423 rt = la->la_rt; 424 } 425 if (la == 0 || rt == 0) { 426 log(LOG_DEBUG, "arpresolve: can't allocate llinfo for %s%s%s\n", 427 inet_ntoa(SIN(dst)->sin_addr), la ? "la" : "", 428 rt ? "rt" : ""); 429 m_freem(m); 430 return (0); 431 } 432 sdl = SDL(rt->rt_gateway); 433 /* 434 * Check the address family and length is valid, the address 435 * is resolved; otherwise, try to resolve. 436 */ 437 if ((rt->rt_expire == 0 || rt->rt_expire > time_second) && 438 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 439 /* 440 * If entry has an expiry time and it is approaching, 441 * see if we need to send an ARP request within this 442 * arpt_down interval. 443 */ 444 if ((rt->rt_expire != 0) && 445 (time_second + la->la_preempt > rt->rt_expire)) { 446 arprequest(ifp, 447 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 448 &SIN(dst)->sin_addr, 449 IF_LLADDR(ifp)); 450 la->la_preempt--; 451 } 452 453 bcopy(LLADDR(sdl), desten, sdl->sdl_alen); 454 return 1; 455 } 456 /* 457 * If ARP is disabled on this interface, stop. 458 * XXX 459 * Probably should not allocate empty llinfo struct if we are 460 * not going to be sending out an arp request. 461 */ 462 if (ifp->if_flags & IFF_NOARP) { 463 m_freem(m); 464 return (0); 465 } 466 /* 467 * There is an arptab entry, but no ethernet address 468 * response yet. Replace the held mbuf with this 469 * latest one. 470 */ 471 if (la->la_hold) 472 m_freem(la->la_hold); 473 la->la_hold = m; 474 if (rt->rt_expire) { 475 rt->rt_flags &= ~RTF_REJECT; 476 if (la->la_asked == 0 || rt->rt_expire != time_second) { 477 rt->rt_expire = time_second; 478 if (la->la_asked++ < arp_maxtries) { 479 arprequest(ifp, 480 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 481 &SIN(dst)->sin_addr, 482 IF_LLADDR(ifp)); 483 } else { 484 rt->rt_flags |= RTF_REJECT; 485 rt->rt_expire += arpt_down; 486 la->la_asked = 0; 487 la->la_preempt = arp_maxtries; 488 } 489 490 } 491 } 492 return (0); 493 } 494 495 /* 496 * Common length and type checks are done here, 497 * then the protocol-specific routine is called. 498 */ 499 static void 500 arpintr(struct mbuf *m) 501 { 502 struct arphdr *ar; 503 504 if (!arpinit_done) { 505 arpinit_done = 1; 506 timeout(arptimer, (caddr_t)0, hz); 507 } 508 if (m->m_len < sizeof(struct arphdr) && 509 ((m = m_pullup(m, sizeof(struct arphdr))) == NULL)) { 510 log(LOG_ERR, "arp: runt packet -- m_pullup failed\n"); 511 return; 512 } 513 ar = mtod(m, struct arphdr *); 514 515 if (ntohs(ar->ar_hrd) != ARPHRD_ETHER && 516 ntohs(ar->ar_hrd) != ARPHRD_IEEE802 && 517 ntohs(ar->ar_hrd) != ARPHRD_ARCNET) { 518 log(LOG_ERR, "arp: unknown hardware address format (0x%2D)\n", 519 (unsigned char *)&ar->ar_hrd, ""); 520 m_freem(m); 521 return; 522 } 523 524 if (m->m_pkthdr.len < arphdr_len(ar) && 525 (m = m_pullup(m, arphdr_len(ar))) == NULL) { 526 log(LOG_ERR, "arp: runt packet\n"); 527 m_freem(m); 528 return; 529 } 530 531 switch (ntohs(ar->ar_pro)) { 532 #ifdef INET 533 case ETHERTYPE_IP: 534 in_arpinput(m); 535 return; 536 #endif 537 } 538 m_freem(m); 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 static int log_arp_movements = 1; 558 559 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW, 560 &log_arp_wrong_iface, 0, 561 "log arp packets arriving on the wrong interface"); 562 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_movements, CTLFLAG_RW, 563 &log_arp_movements, 0, 564 "log arp replies from MACs different than the one in the cache"); 565 566 567 static void 568 in_arpinput(m) 569 struct mbuf *m; 570 { 571 register struct arphdr *ah; 572 register struct ifnet *ifp = m->m_pkthdr.rcvif; 573 struct ether_header *eh; 574 struct arc_header *arh; 575 struct iso88025_header *th = (struct iso88025_header *)0; 576 struct iso88025_sockaddr_dl_data *trld; 577 register struct llinfo_arp *la = 0; 578 register struct rtentry *rt; 579 struct ifaddr *ifa; 580 struct in_ifaddr *ia; 581 struct sockaddr_dl *sdl; 582 struct sockaddr sa; 583 struct in_addr isaddr, itaddr, myaddr; 584 int op, rif_len; 585 int req_len; 586 587 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 588 if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) { 589 log(LOG_ERR, "in_arp: runt packet -- m_pullup failed\n"); 590 return; 591 } 592 593 ah = mtod(m, struct arphdr *); 594 op = ntohs(ah->ar_op); 595 (void)memcpy(&isaddr, ar_spa(ah), sizeof (isaddr)); 596 (void)memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr)); 597 #ifdef BRIDGE 598 #define BRIDGE_TEST (do_bridge) 599 #else 600 #define BRIDGE_TEST (0) /* cc will optimise the test away */ 601 #endif 602 /* 603 * For a bridge, we want to check the address irrespective 604 * of the receive interface. (This will change slightly 605 * when we have clusters of interfaces). 606 */ 607 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) 608 if ((BRIDGE_TEST || (ia->ia_ifp == ifp)) && 609 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) 610 goto match; 611 LIST_FOREACH(ia, INADDR_HASH(isaddr.s_addr), ia_hash) 612 if ((BRIDGE_TEST || (ia->ia_ifp == ifp)) && 613 isaddr.s_addr == ia->ia_addr.sin_addr.s_addr) 614 goto match; 615 /* 616 * No match, use the first inet address on the receive interface 617 * as a dummy address for the rest of the function. 618 */ 619 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) 620 if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_INET) { 621 ia = ifatoia(ifa); 622 goto match; 623 } 624 /* 625 * If bridging, fall back to using any inet address. 626 */ 627 if (!BRIDGE_TEST || 628 (ia = TAILQ_FIRST(&in_ifaddrhead)) == NULL) { 629 m_freem(m); 630 return; 631 } 632 match: 633 myaddr = ia->ia_addr.sin_addr; 634 if (!bcmp(ar_sha(ah), IF_LLADDR(ifp), ifp->if_addrlen)) { 635 m_freem(m); /* it's from me, ignore it. */ 636 return; 637 } 638 if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) { 639 log(LOG_ERR, 640 "arp: link address is broadcast for IP address %s!\n", 641 inet_ntoa(isaddr)); 642 m_freem(m); 643 return; 644 } 645 if (isaddr.s_addr == myaddr.s_addr) { 646 log(LOG_ERR, 647 "arp: %*D is using my IP address %s!\n", 648 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 649 inet_ntoa(isaddr)); 650 itaddr = myaddr; 651 goto reply; 652 } 653 la = arplookup(isaddr.s_addr, itaddr.s_addr == myaddr.s_addr, 0); 654 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { 655 /* the following is not an error when doing bridging */ 656 if (!BRIDGE_TEST && rt->rt_ifp != ifp) { 657 if (log_arp_wrong_iface) 658 log(LOG_ERR, "arp: %s is on %s%d but got reply from %*D on %s%d\n", 659 inet_ntoa(isaddr), 660 rt->rt_ifp->if_name, rt->rt_ifp->if_unit, 661 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 662 ifp->if_name, ifp->if_unit); 663 goto reply; 664 } 665 if (sdl->sdl_alen && 666 bcmp(ar_sha(ah), LLADDR(sdl), sdl->sdl_alen)) { 667 if (rt->rt_expire) { 668 if (log_arp_movements) 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_asked = 0; 738 la->la_preempt = arp_maxtries; 739 if (la->la_hold) { 740 (*ifp->if_output)(ifp, la->la_hold, 741 rt_key(rt), rt); 742 la->la_hold = 0; 743 } 744 } 745 reply: 746 if (op != ARPOP_REQUEST) { 747 m_freem(m); 748 return; 749 } 750 if (itaddr.s_addr == myaddr.s_addr) { 751 /* I am the target */ 752 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 753 (void)memcpy(ar_sha(ah), IF_LLADDR(ifp), ah->ar_hln); 754 } else { 755 la = arplookup(itaddr.s_addr, 0, SIN_PROXY); 756 if (la == NULL) { 757 struct sockaddr_in sin; 758 759 if (!arp_proxyall) { 760 m_freem(m); 761 return; 762 } 763 764 bzero(&sin, sizeof sin); 765 sin.sin_family = AF_INET; 766 sin.sin_len = sizeof sin; 767 sin.sin_addr = itaddr; 768 769 rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL); 770 if (!rt) { 771 m_freem(m); 772 return; 773 } 774 /* 775 * Don't send proxies for nodes on the same interface 776 * as this one came out of, or we'll get into a fight 777 * over who claims what Ether address. 778 */ 779 if (rt->rt_ifp == ifp) { 780 rtfree(rt); 781 m_freem(m); 782 return; 783 } 784 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 785 (void)memcpy(ar_sha(ah), IF_LLADDR(ifp), ah->ar_hln); 786 rtfree(rt); 787 788 /* 789 * Also check that the node which sent the ARP packet 790 * is on the the interface we expect it to be on. This 791 * avoids ARP chaos if an interface is connected to the 792 * wrong network. 793 */ 794 sin.sin_addr = isaddr; 795 796 rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL); 797 if (!rt) { 798 m_freem(m); 799 return; 800 } 801 if (rt->rt_ifp != ifp) { 802 log(LOG_INFO, "arp_proxy: ignoring request" 803 " from %s via %s%d, expecting %s%d\n", 804 inet_ntoa(isaddr), ifp->if_name, 805 ifp->if_unit, rt->rt_ifp->if_name, 806 rt->rt_ifp->if_unit); 807 rtfree(rt); 808 m_freem(m); 809 return; 810 } 811 rtfree(rt); 812 813 #ifdef DEBUG_PROXY 814 printf("arp: proxying for %s\n", 815 inet_ntoa(itaddr)); 816 #endif 817 } else { 818 rt = la->la_rt; 819 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 820 sdl = SDL(rt->rt_gateway); 821 (void)memcpy(ar_sha(ah), LLADDR(sdl), ah->ar_hln); 822 } 823 } 824 825 (void)memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln); 826 (void)memcpy(ar_spa(ah), &itaddr, ah->ar_pln); 827 ah->ar_op = htons(ARPOP_REPLY); 828 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 829 switch (ifp->if_type) { 830 case IFT_ARCNET: 831 arh = (struct arc_header *)sa.sa_data; 832 arh->arc_dhost = *ar_tha(ah); 833 arh->arc_type = ARCTYPE_ARP; 834 break; 835 836 case IFT_ISO88025: 837 /* Re-arrange the source/dest address */ 838 memcpy(th->iso88025_dhost, th->iso88025_shost, 839 sizeof(th->iso88025_dhost)); 840 memcpy(th->iso88025_shost, IF_LLADDR(ifp), 841 sizeof(th->iso88025_shost)); 842 /* Set the source routing bit if neccesary */ 843 if (th->iso88025_dhost[0] & TR_RII) { 844 th->iso88025_dhost[0] &= ~TR_RII; 845 if (TR_RCF_RIFLEN(th->rcf) > 2) 846 th->iso88025_shost[0] |= TR_RII; 847 } 848 /* Copy the addresses, ac and fc into sa_data */ 849 memcpy(sa.sa_data, th->iso88025_dhost, 850 sizeof(th->iso88025_dhost) * 2); 851 sa.sa_data[(sizeof(th->iso88025_dhost) * 2)] = TR_AC; 852 sa.sa_data[(sizeof(th->iso88025_dhost) * 2) + 1] = TR_LLC_FRAME; 853 break; 854 case IFT_ETHER: 855 case IFT_FDDI: 856 /* 857 * May not be correct for types not explictly 858 * listed, but it is our best guess. 859 */ 860 default: 861 eh = (struct ether_header *)sa.sa_data; 862 (void)memcpy(eh->ether_dhost, ar_tha(ah), 863 sizeof(eh->ether_dhost)); 864 eh->ether_type = htons(ETHERTYPE_ARP); 865 break; 866 } 867 sa.sa_family = AF_UNSPEC; 868 sa.sa_len = sizeof(sa); 869 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 870 return; 871 } 872 #endif 873 874 /* 875 * Free an arp entry. 876 */ 877 static void 878 arptfree(la) 879 register struct llinfo_arp *la; 880 { 881 register struct rtentry *rt = la->la_rt; 882 register struct sockaddr_dl *sdl; 883 if (rt == 0) 884 panic("arptfree"); 885 if (rt->rt_refcnt > 0 && (sdl = SDL(rt->rt_gateway)) && 886 sdl->sdl_family == AF_LINK) { 887 sdl->sdl_alen = 0; 888 la->la_preempt = la->la_asked = 0; 889 rt->rt_flags &= ~RTF_REJECT; 890 return; 891 } 892 rtrequest(RTM_DELETE, rt_key(rt), (struct sockaddr *)0, rt_mask(rt), 893 0, (struct rtentry **)0); 894 } 895 /* 896 * Lookup or enter a new address in arptab. 897 */ 898 static struct llinfo_arp * 899 arplookup(addr, create, proxy) 900 u_long addr; 901 int create, proxy; 902 { 903 register struct rtentry *rt; 904 static struct sockaddr_inarp sin = {sizeof(sin), AF_INET }; 905 const char *why = 0; 906 907 sin.sin_addr.s_addr = addr; 908 sin.sin_other = proxy ? SIN_PROXY : 0; 909 rt = rtalloc1((struct sockaddr *)&sin, create, 0UL); 910 if (rt == 0) 911 return (0); 912 rt->rt_refcnt--; 913 914 if (rt->rt_flags & RTF_GATEWAY) 915 why = "host is not on local network"; 916 else if ((rt->rt_flags & RTF_LLINFO) == 0) 917 why = "could not allocate llinfo"; 918 else if (rt->rt_gateway->sa_family != AF_LINK) 919 why = "gateway route is not ours"; 920 921 if (why) { 922 if (create) 923 log(LOG_DEBUG, "arplookup %s failed: %s\n", 924 inet_ntoa(sin.sin_addr), why); 925 926 /* If there are no references to this route, purge it */ 927 if (rt->rt_refcnt <= 0 && 928 (rt->rt_flags & RTF_WASCLONED) == RTF_WASCLONED) { 929 rtrequest(RTM_DELETE, 930 (struct sockaddr *)rt_key(rt), 931 rt->rt_gateway, rt_mask(rt), 932 rt->rt_flags, 0); 933 } 934 return (0); 935 } 936 return ((struct llinfo_arp *)rt->rt_llinfo); 937 } 938 939 void 940 arp_ifinit(ifp, ifa) 941 struct ifnet *ifp; 942 struct ifaddr *ifa; 943 { 944 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY) 945 arprequest(ifp, &IA_SIN(ifa)->sin_addr, 946 &IA_SIN(ifa)->sin_addr, IF_LLADDR(ifp)); 947 ifa->ifa_rtrequest = arp_rtrequest; 948 ifa->ifa_flags |= RTF_CLONING; 949 } 950 951 static void 952 arp_init(void) 953 { 954 955 arpintrq.ifq_maxlen = 50; 956 mtx_init(&arpintrq.ifq_mtx, "arp_inq", NULL, MTX_DEF); 957 LIST_INIT(&llinfo_arp); 958 netisr_register(NETISR_ARP, arpintr, &arpintrq); 959 } 960 961 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0);
Cache object: 09eac9c409a28a6f5e78489a627b85a2
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