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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/5.0/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 long la_asked; /* last time we QUERIED for this addr */ 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; 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_init(void); 121 static void arp_rtrequest(int, struct rtentry *, struct rt_addrinfo *); 122 static void arprequest(struct ifnet *, 123 struct in_addr *, struct in_addr *, u_char *); 124 static void arpintr(void); 125 static void arptfree(struct llinfo_arp *); 126 static void arptimer(void *); 127 static struct llinfo_arp 128 *arplookup(u_long, int, int); 129 #ifdef INET 130 static void in_arpinput(struct mbuf *); 131 #endif 132 133 /* 134 * Timeout routine. Age arp_tab entries periodically. 135 */ 136 /* ARGSUSED */ 137 static void 138 arptimer(ignored_arg) 139 void *ignored_arg; 140 { 141 int s = splnet(); 142 register struct llinfo_arp *la = LIST_FIRST(&llinfo_arp); 143 struct llinfo_arp *ola; 144 145 timeout(arptimer, (caddr_t)0, arpt_prune * hz); 146 while ((ola = la) != 0) { 147 register struct rtentry *rt = la->la_rt; 148 la = LIST_NEXT(la, la_le); 149 if (rt->rt_expire && rt->rt_expire <= time_second) 150 arptfree(ola); /* timer has expired, clear */ 151 } 152 splx(s); 153 } 154 155 /* 156 * Parallel to llc_rtrequest. 157 */ 158 static void 159 arp_rtrequest(req, rt, info) 160 int req; 161 register struct rtentry *rt; 162 struct rt_addrinfo *info; 163 { 164 register struct sockaddr *gate = rt->rt_gateway; 165 register struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo; 166 static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK}; 167 168 if (!arpinit_done) { 169 arpinit_done = 1; 170 timeout(arptimer, (caddr_t)0, hz); 171 } 172 if (rt->rt_flags & RTF_GATEWAY) 173 return; 174 switch (req) { 175 176 case RTM_ADD: 177 /* 178 * XXX: If this is a manually added route to interface 179 * such as older version of routed or gated might provide, 180 * restore cloning bit. 181 */ 182 if ((rt->rt_flags & RTF_HOST) == 0 && 183 SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff) 184 rt->rt_flags |= RTF_CLONING; 185 if (rt->rt_flags & RTF_CLONING) { 186 /* 187 * Case 1: This route should come from a route to iface. 188 */ 189 rt_setgate(rt, rt_key(rt), 190 (struct sockaddr *)&null_sdl); 191 gate = rt->rt_gateway; 192 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 193 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 194 rt->rt_expire = time_second; 195 break; 196 } 197 /* Announce a new entry if requested. */ 198 if (rt->rt_flags & RTF_ANNOUNCE) 199 arprequest(rt->rt_ifp, 200 &SIN(rt_key(rt))->sin_addr, 201 &SIN(rt_key(rt))->sin_addr, 202 (u_char *)LLADDR(SDL(gate))); 203 /*FALLTHROUGH*/ 204 case RTM_RESOLVE: 205 if (gate->sa_family != AF_LINK || 206 gate->sa_len < sizeof(null_sdl)) { 207 log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n"); 208 break; 209 } 210 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 211 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 212 if (la != 0) 213 break; /* This happens on a route change */ 214 /* 215 * Case 2: This route may come from cloning, or a manual route 216 * add with a LL address. 217 */ 218 R_Malloc(la, struct llinfo_arp *, sizeof(*la)); 219 rt->rt_llinfo = (caddr_t)la; 220 if (la == 0) { 221 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); 222 break; 223 } 224 arp_inuse++, arp_allocated++; 225 Bzero(la, sizeof(*la)); 226 la->la_rt = rt; 227 rt->rt_flags |= RTF_LLINFO; 228 LIST_INSERT_HEAD(&llinfo_arp, la, la_le); 229 230 #ifdef INET 231 /* 232 * This keeps the multicast addresses from showing up 233 * in `arp -a' listings as unresolved. It's not actually 234 * functional. Then the same for broadcast. 235 */ 236 if (IN_MULTICAST(ntohl(SIN(rt_key(rt))->sin_addr.s_addr)) && 237 rt->rt_ifp->if_type != IFT_ARCNET) { 238 ETHER_MAP_IP_MULTICAST(&SIN(rt_key(rt))->sin_addr, 239 LLADDR(SDL(gate))); 240 SDL(gate)->sdl_alen = 6; 241 rt->rt_expire = 0; 242 } 243 if (in_broadcast(SIN(rt_key(rt))->sin_addr, rt->rt_ifp)) { 244 memcpy(LLADDR(SDL(gate)), rt->rt_ifp->if_broadcastaddr, 245 rt->rt_ifp->if_addrlen); 246 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen; 247 rt->rt_expire = 0; 248 } 249 #endif 250 251 if (SIN(rt_key(rt))->sin_addr.s_addr == 252 (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) { 253 /* 254 * This test used to be 255 * if (loif.if_flags & IFF_UP) 256 * It allowed local traffic to be forced 257 * through the hardware by configuring the loopback down. 258 * However, it causes problems during network configuration 259 * for boards that can't receive packets they send. 260 * It is now necessary to clear "useloopback" and remove 261 * the route to force traffic out to the hardware. 262 */ 263 rt->rt_expire = 0; 264 Bcopy(IF_LLADDR(rt->rt_ifp), LLADDR(SDL(gate)), 265 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen); 266 if (useloopback) 267 rt->rt_ifp = loif; 268 269 } 270 break; 271 272 case RTM_DELETE: 273 if (la == 0) 274 break; 275 arp_inuse--; 276 LIST_REMOVE(la, la_le); 277 rt->rt_llinfo = 0; 278 rt->rt_flags &= ~RTF_LLINFO; 279 if (la->la_hold) 280 m_freem(la->la_hold); 281 Free((caddr_t)la); 282 } 283 } 284 285 /* 286 * Broadcast an ARP request. Caller specifies: 287 * - arp header source ip address 288 * - arp header target ip address 289 * - arp header source ethernet address 290 */ 291 static void 292 arprequest(ifp, sip, tip, enaddr) 293 register struct ifnet *ifp; 294 register struct in_addr *sip, *tip; 295 register u_char *enaddr; 296 { 297 register struct mbuf *m; 298 register struct ether_header *eh; 299 register struct arc_header *arh; 300 register struct arphdr *ah; 301 struct sockaddr sa; 302 static u_char llcx[] = { 0x82, 0x40, LLC_SNAP_LSAP, LLC_SNAP_LSAP, 303 LLC_UI, 0x00, 0x00, 0x00, 0x08, 0x06 }; 304 u_short ar_hrd; 305 306 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 307 return; 308 m->m_pkthdr.rcvif = (struct ifnet *)0; 309 #ifdef MAC 310 mac_create_mbuf_linklayer(ifp, m); 311 #endif 312 switch (ifp->if_type) { 313 case IFT_ARCNET: 314 ar_hrd = htons(ARPHRD_ARCNET); 315 316 m->m_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 317 m->m_pkthdr.len = m->m_len; 318 MH_ALIGN(m, m->m_len); 319 320 arh = (struct arc_header *)sa.sa_data; 321 arh->arc_dhost = *ifp->if_broadcastaddr; 322 arh->arc_type = ARCTYPE_ARP; 323 324 ah = mtod(m, struct arphdr *); 325 break; 326 327 case IFT_ISO88025: 328 ar_hrd = htons(ARPHRD_IEEE802); 329 330 m->m_len = sizeof(llcx) + 331 arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 332 m->m_pkthdr.len = m->m_len; 333 MH_ALIGN(m, m->m_len); 334 335 (void)memcpy(mtod(m, caddr_t), llcx, sizeof(llcx)); 336 (void)memcpy(sa.sa_data, ifp->if_broadcastaddr, 6); 337 (void)memcpy(sa.sa_data + 6, enaddr, 6); 338 sa.sa_data[6] |= TR_RII; 339 sa.sa_data[12] = TR_AC; 340 sa.sa_data[13] = TR_LLC_FRAME; 341 342 ah = (struct arphdr *)(mtod(m, char *) + sizeof(llcx)); 343 break; 344 case IFT_FDDI: 345 case IFT_ETHER: 346 /* 347 * This may not be correct for types not explicitly 348 * listed, but this is our best guess 349 */ 350 default: 351 ar_hrd = htons(ARPHRD_ETHER); 352 353 m->m_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 354 m->m_pkthdr.len = m->m_len; 355 MH_ALIGN(m, m->m_len); 356 357 eh = (struct ether_header *)sa.sa_data; 358 /* if_output will not swap */ 359 eh->ether_type = htons(ETHERTYPE_ARP); 360 (void)memcpy(eh->ether_dhost, ifp->if_broadcastaddr, 361 sizeof(eh->ether_dhost)); 362 363 ah = mtod(m, struct arphdr *); 364 break; 365 } 366 367 ah->ar_hrd = ar_hrd; 368 ah->ar_pro = htons(ETHERTYPE_IP); 369 ah->ar_hln = ifp->if_addrlen; /* hardware address length */ 370 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 371 ah->ar_op = htons(ARPOP_REQUEST); 372 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln); 373 (void)memcpy(ar_spa(ah), sip, ah->ar_pln); 374 (void)memcpy(ar_tpa(ah), tip, ah->ar_pln); 375 376 sa.sa_family = AF_UNSPEC; 377 sa.sa_len = sizeof(sa); 378 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 379 } 380 381 /* 382 * Resolve an IP address into an ethernet address. If success, 383 * desten is filled in. If there is no entry in arptab, 384 * set one up and broadcast a request for the IP address. 385 * Hold onto this mbuf and resend it once the address 386 * is finally resolved. A return value of 1 indicates 387 * that desten has been filled in and the packet should be sent 388 * normally; a 0 return indicates that the packet has been 389 * taken over here, either now or for later transmission. 390 */ 391 int 392 arpresolve(ifp, rt, m, dst, desten, rt0) 393 register struct ifnet *ifp; 394 register struct rtentry *rt; 395 struct mbuf *m; 396 register struct sockaddr *dst; 397 register u_char *desten; 398 struct rtentry *rt0; 399 { 400 struct llinfo_arp *la = 0; 401 struct sockaddr_dl *sdl; 402 403 if (m->m_flags & M_BCAST) { /* broadcast */ 404 (void)memcpy(desten, ifp->if_broadcastaddr, ifp->if_addrlen); 405 return (1); 406 } 407 if (m->m_flags & M_MCAST && ifp->if_type != IFT_ARCNET) {/* multicast */ 408 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); 409 return(1); 410 } 411 if (rt) 412 la = (struct llinfo_arp *)rt->rt_llinfo; 413 if (la == 0) { 414 la = arplookup(SIN(dst)->sin_addr.s_addr, 1, 0); 415 if (la) 416 rt = la->la_rt; 417 } 418 if (la == 0 || rt == 0) { 419 log(LOG_DEBUG, "arpresolve: can't allocate llinfo for %s%s%s\n", 420 inet_ntoa(SIN(dst)->sin_addr), la ? "la" : "", 421 rt ? "rt" : ""); 422 m_freem(m); 423 return (0); 424 } 425 sdl = SDL(rt->rt_gateway); 426 /* 427 * Check the address family and length is valid, the address 428 * is resolved; otherwise, try to resolve. 429 */ 430 if ((rt->rt_expire == 0 || rt->rt_expire > time_second) && 431 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 432 /* 433 * If entry has an expiry time and it is approaching, 434 * see if we need to send an ARP request within this 435 * arpt_down interval. 436 */ 437 if ((rt->rt_expire != 0) && 438 (time_second + (arp_maxtries - la->la_asked) * arpt_down > 439 rt->rt_expire)) { 440 arprequest(ifp, 441 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 442 &SIN(dst)->sin_addr, 443 IF_LLADDR(ifp)); 444 la->la_asked++; 445 } 446 447 bcopy(LLADDR(sdl), desten, sdl->sdl_alen); 448 return 1; 449 } 450 /* 451 * If ARP is disabled on this interface, stop. 452 * XXX 453 * Probably should not allocate empty llinfo struct if we are 454 * not going to be sending out an arp request. 455 */ 456 if (ifp->if_flags & IFF_NOARP) { 457 m_freem(m); 458 return (0); 459 } 460 /* 461 * There is an arptab entry, but no ethernet address 462 * response yet. Replace the held mbuf with this 463 * latest one. 464 */ 465 if (la->la_hold) 466 m_freem(la->la_hold); 467 la->la_hold = m; 468 if (rt->rt_expire) { 469 rt->rt_flags &= ~RTF_REJECT; 470 if (la->la_asked == 0 || rt->rt_expire != time_second) { 471 rt->rt_expire = time_second; 472 if (la->la_asked++ < arp_maxtries) 473 arprequest(ifp, 474 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 475 &SIN(dst)->sin_addr, 476 IF_LLADDR(ifp)); 477 else { 478 rt->rt_flags |= RTF_REJECT; 479 rt->rt_expire += arpt_down; 480 la->la_asked = 0; 481 } 482 483 } 484 } 485 return (0); 486 } 487 488 /* 489 * Common length and type checks are done here, 490 * then the protocol-specific routine is called. 491 */ 492 static void 493 arpintr() 494 { 495 register struct mbuf *m; 496 register struct arphdr *ar; 497 int s; 498 499 if (!arpinit_done) { 500 arpinit_done = 1; 501 timeout(arptimer, (caddr_t)0, hz); 502 } 503 while (arpintrq.ifq_head) { 504 s = splimp(); 505 IF_DEQUEUE(&arpintrq, m); 506 splx(s); 507 if (m == 0 || (m->m_flags & M_PKTHDR) == 0) 508 panic("arpintr"); 509 510 if (m->m_len < sizeof(struct arphdr) && 511 ((m = m_pullup(m, sizeof(struct arphdr))) == NULL)) { 512 log(LOG_ERR, "arp: runt packet -- m_pullup failed\n"); 513 continue; 514 } 515 ar = mtod(m, struct arphdr *); 516 517 if (ntohs(ar->ar_hrd) != ARPHRD_ETHER 518 && ntohs(ar->ar_hrd) != ARPHRD_IEEE802 519 && ntohs(ar->ar_hrd) != ARPHRD_ARCNET) { 520 log(LOG_ERR, 521 "arp: unknown hardware address format (0x%2D)\n", 522 (unsigned char *)&ar->ar_hrd, ""); 523 m_freem(m); 524 continue; 525 } 526 527 if (m->m_pkthdr.len < arphdr_len(ar) && 528 (m = m_pullup(m, arphdr_len(ar))) == NULL) { 529 log(LOG_ERR, "arp: runt packet\n"); 530 m_freem(m); 531 continue; 532 } 533 534 switch (ntohs(ar->ar_pro)) { 535 #ifdef INET 536 case ETHERTYPE_IP: 537 in_arpinput(m); 538 continue; 539 #endif 540 } 541 m_freem(m); 542 } 543 } 544 545 #ifdef INET 546 /* 547 * ARP for Internet protocols on 10 Mb/s Ethernet. 548 * Algorithm is that given in RFC 826. 549 * In addition, a sanity check is performed on the sender 550 * protocol address, to catch impersonators. 551 * We no longer handle negotiations for use of trailer protocol: 552 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 553 * along with IP replies if we wanted trailers sent to us, 554 * and also sent them in response to IP replies. 555 * This allowed either end to announce the desire to receive 556 * trailer packets. 557 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 558 * but formerly didn't normally send requests. 559 */ 560 static int log_arp_wrong_iface = 1; 561 static int log_arp_movements = 1; 562 563 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW, 564 &log_arp_wrong_iface, 0, 565 "log arp packets arriving on the wrong interface"); 566 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_movements, CTLFLAG_RW, 567 &log_arp_movements, 0, 568 "log arp replies from MACs different than the one in the cache"); 569 570 571 static void 572 in_arpinput(m) 573 struct mbuf *m; 574 { 575 register struct arphdr *ah; 576 register struct ifnet *ifp = m->m_pkthdr.rcvif; 577 struct ether_header *eh; 578 struct arc_header *arh; 579 struct iso88025_header *th = (struct iso88025_header *)0; 580 struct iso88025_sockaddr_dl_data *trld; 581 register struct llinfo_arp *la = 0; 582 register struct rtentry *rt; 583 struct ifaddr *ifa; 584 struct in_ifaddr *ia; 585 struct sockaddr_dl *sdl; 586 struct sockaddr sa; 587 struct in_addr isaddr, itaddr, myaddr; 588 int op, rif_len; 589 int req_len; 590 591 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 592 if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) { 593 log(LOG_ERR, "in_arp: runt packet -- m_pullup failed\n"); 594 return; 595 } 596 597 ah = mtod(m, struct arphdr *); 598 op = ntohs(ah->ar_op); 599 (void)memcpy(&isaddr, ar_spa(ah), sizeof (isaddr)); 600 (void)memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr)); 601 #ifdef BRIDGE 602 #define BRIDGE_TEST (do_bridge) 603 #else 604 #define BRIDGE_TEST (0) /* cc will optimise the test away */ 605 #endif 606 /* 607 * For a bridge, we want to check the address irrespective 608 * of the receive interface. (This will change slightly 609 * when we have clusters of interfaces). 610 */ 611 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) 612 if ((BRIDGE_TEST || (ia->ia_ifp == ifp)) && 613 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) 614 goto match; 615 LIST_FOREACH(ia, INADDR_HASH(isaddr.s_addr), ia_hash) 616 if ((BRIDGE_TEST || (ia->ia_ifp == ifp)) && 617 isaddr.s_addr == ia->ia_addr.sin_addr.s_addr) 618 goto match; 619 /* 620 * No match, use the first inet address on the receive interface 621 * as a dummy address for the rest of the function. 622 */ 623 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) 624 if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_INET) { 625 ia = ifatoia(ifa); 626 goto match; 627 } 628 /* 629 * If bridging, fall back to using any inet address. 630 */ 631 if (!BRIDGE_TEST || 632 (ia = TAILQ_FIRST(&in_ifaddrhead)) == NULL) { 633 m_freem(m); 634 return; 635 } 636 match: 637 myaddr = ia->ia_addr.sin_addr; 638 if (!bcmp(ar_sha(ah), IF_LLADDR(ifp), ifp->if_addrlen)) { 639 m_freem(m); /* it's from me, ignore it. */ 640 return; 641 } 642 if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) { 643 log(LOG_ERR, 644 "arp: link address is broadcast for IP address %s!\n", 645 inet_ntoa(isaddr)); 646 m_freem(m); 647 return; 648 } 649 if (isaddr.s_addr == myaddr.s_addr) { 650 log(LOG_ERR, 651 "arp: %*D is using my IP address %s!\n", 652 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 653 inet_ntoa(isaddr)); 654 itaddr = myaddr; 655 goto reply; 656 } 657 la = arplookup(isaddr.s_addr, itaddr.s_addr == myaddr.s_addr, 0); 658 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { 659 /* the following is not an error when doing bridging */ 660 if (!BRIDGE_TEST && rt->rt_ifp != ifp) { 661 if (log_arp_wrong_iface) 662 log(LOG_ERR, "arp: %s is on %s%d but got reply from %*D on %s%d\n", 663 inet_ntoa(isaddr), 664 rt->rt_ifp->if_name, rt->rt_ifp->if_unit, 665 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 666 ifp->if_name, ifp->if_unit); 667 goto reply; 668 } 669 if (sdl->sdl_alen && 670 bcmp(ar_sha(ah), LLADDR(sdl), sdl->sdl_alen)) { 671 if (rt->rt_expire) { 672 if (log_arp_movements) 673 log(LOG_INFO, "arp: %s moved from %*D to %*D on %s%d\n", 674 inet_ntoa(isaddr), 675 ifp->if_addrlen, (u_char *)LLADDR(sdl), ":", 676 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 677 ifp->if_name, ifp->if_unit); 678 } else { 679 log(LOG_ERR, 680 "arp: %*D attempts to modify permanent entry for %s on %s%d\n", 681 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 682 inet_ntoa(isaddr), ifp->if_name, ifp->if_unit); 683 goto reply; 684 } 685 } 686 /* 687 * sanity check for the address length. 688 * XXX this does not work for protocols with variable address 689 * length. -is 690 */ 691 if (sdl->sdl_alen && 692 sdl->sdl_alen != ah->ar_hln) { 693 log(LOG_WARNING, 694 "arp from %*D: new addr len %d, was %d", 695 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 696 ah->ar_hln, sdl->sdl_alen); 697 } 698 if (ifp->if_addrlen != ah->ar_hln) { 699 log(LOG_WARNING, 700 "arp from %*D: addr len: new %d, i/f %d (ignored)", 701 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 702 ah->ar_hln, ifp->if_addrlen); 703 goto reply; 704 } 705 (void)memcpy(LLADDR(sdl), ar_sha(ah), 706 sdl->sdl_alen = ah->ar_hln); 707 /* 708 * If we receive an arp from a token-ring station over 709 * a token-ring nic then try to save the source 710 * routing info. 711 */ 712 if (ifp->if_type == IFT_ISO88025) { 713 th = (struct iso88025_header *)m->m_pkthdr.header; 714 trld = SDL_ISO88025(sdl); 715 rif_len = TR_RCF_RIFLEN(th->rcf); 716 if ((th->iso88025_shost[0] & TR_RII) && 717 (rif_len > 2)) { 718 trld->trld_rcf = th->rcf; 719 trld->trld_rcf ^= htons(TR_RCF_DIR); 720 memcpy(trld->trld_route, th->rd, rif_len - 2); 721 trld->trld_rcf &= ~htons(TR_RCF_BCST_MASK); 722 /* 723 * Set up source routing information for 724 * reply packet (XXX) 725 */ 726 m->m_data -= rif_len; 727 m->m_len += rif_len; 728 m->m_pkthdr.len += rif_len; 729 } else { 730 th->iso88025_shost[0] &= ~TR_RII; 731 trld->trld_rcf = 0; 732 } 733 m->m_data -= 8; 734 m->m_len += 8; 735 m->m_pkthdr.len += 8; 736 th->rcf = trld->trld_rcf; 737 } 738 if (rt->rt_expire) 739 rt->rt_expire = time_second + arpt_keep; 740 rt->rt_flags &= ~RTF_REJECT; 741 la->la_asked = 0; 742 if (la->la_hold) { 743 (*ifp->if_output)(ifp, la->la_hold, 744 rt_key(rt), rt); 745 la->la_hold = 0; 746 } 747 } 748 reply: 749 if (op != ARPOP_REQUEST) { 750 m_freem(m); 751 return; 752 } 753 if (itaddr.s_addr == myaddr.s_addr) { 754 /* I am the target */ 755 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 756 (void)memcpy(ar_sha(ah), IF_LLADDR(ifp), ah->ar_hln); 757 } else { 758 la = arplookup(itaddr.s_addr, 0, SIN_PROXY); 759 if (la == NULL) { 760 struct sockaddr_in sin; 761 762 if (!arp_proxyall) { 763 m_freem(m); 764 return; 765 } 766 767 bzero(&sin, sizeof sin); 768 sin.sin_family = AF_INET; 769 sin.sin_len = sizeof sin; 770 sin.sin_addr = itaddr; 771 772 rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL); 773 if (!rt) { 774 m_freem(m); 775 return; 776 } 777 /* 778 * Don't send proxies for nodes on the same interface 779 * as this one came out of, or we'll get into a fight 780 * over who claims what Ether address. 781 */ 782 if (rt->rt_ifp == ifp) { 783 rtfree(rt); 784 m_freem(m); 785 return; 786 } 787 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 788 (void)memcpy(ar_sha(ah), IF_LLADDR(ifp), ah->ar_hln); 789 rtfree(rt); 790 791 /* 792 * Also check that the node which sent the ARP packet 793 * is on the the interface we expect it to be on. This 794 * avoids ARP chaos if an interface is connected to the 795 * wrong network. 796 */ 797 sin.sin_addr = isaddr; 798 799 rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL); 800 if (!rt) { 801 m_freem(m); 802 return; 803 } 804 if (rt->rt_ifp != ifp) { 805 log(LOG_INFO, "arp_proxy: ignoring request" 806 " from %s via %s%d, expecting %s%d\n", 807 inet_ntoa(isaddr), ifp->if_name, 808 ifp->if_unit, rt->rt_ifp->if_name, 809 rt->rt_ifp->if_unit); 810 rtfree(rt); 811 m_freem(m); 812 return; 813 } 814 rtfree(rt); 815 816 #ifdef DEBUG_PROXY 817 printf("arp: proxying for %s\n", 818 inet_ntoa(itaddr)); 819 #endif 820 } else { 821 rt = la->la_rt; 822 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 823 sdl = SDL(rt->rt_gateway); 824 (void)memcpy(ar_sha(ah), LLADDR(sdl), ah->ar_hln); 825 } 826 } 827 828 (void)memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln); 829 (void)memcpy(ar_spa(ah), &itaddr, ah->ar_pln); 830 ah->ar_op = htons(ARPOP_REPLY); 831 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 832 switch (ifp->if_type) { 833 case IFT_ARCNET: 834 arh = (struct arc_header *)sa.sa_data; 835 arh->arc_dhost = *ar_tha(ah); 836 arh->arc_type = ARCTYPE_ARP; 837 break; 838 839 case IFT_ISO88025: 840 /* Re-arrange the source/dest address */ 841 memcpy(th->iso88025_dhost, th->iso88025_shost, 842 sizeof(th->iso88025_dhost)); 843 memcpy(th->iso88025_shost, IF_LLADDR(ifp), 844 sizeof(th->iso88025_shost)); 845 /* Set the source routing bit if neccesary */ 846 if (th->iso88025_dhost[0] & TR_RII) { 847 th->iso88025_dhost[0] &= ~TR_RII; 848 if (TR_RCF_RIFLEN(th->rcf) > 2) 849 th->iso88025_shost[0] |= TR_RII; 850 } 851 /* Copy the addresses, ac and fc into sa_data */ 852 memcpy(sa.sa_data, th->iso88025_dhost, 853 sizeof(th->iso88025_dhost) * 2); 854 sa.sa_data[(sizeof(th->iso88025_dhost) * 2)] = TR_AC; 855 sa.sa_data[(sizeof(th->iso88025_dhost) * 2) + 1] = TR_LLC_FRAME; 856 break; 857 case IFT_ETHER: 858 case IFT_FDDI: 859 /* 860 * May not be correct for types not explictly 861 * listed, but it is our best guess. 862 */ 863 default: 864 eh = (struct ether_header *)sa.sa_data; 865 (void)memcpy(eh->ether_dhost, ar_tha(ah), 866 sizeof(eh->ether_dhost)); 867 eh->ether_type = htons(ETHERTYPE_ARP); 868 break; 869 } 870 sa.sa_family = AF_UNSPEC; 871 sa.sa_len = sizeof(sa); 872 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 873 return; 874 } 875 #endif 876 877 /* 878 * Free an arp entry. 879 */ 880 static void 881 arptfree(la) 882 register struct llinfo_arp *la; 883 { 884 register struct rtentry *rt = la->la_rt; 885 register struct sockaddr_dl *sdl; 886 if (rt == 0) 887 panic("arptfree"); 888 if (rt->rt_refcnt > 0 && (sdl = SDL(rt->rt_gateway)) && 889 sdl->sdl_family == AF_LINK) { 890 sdl->sdl_alen = 0; 891 la->la_asked = 0; 892 rt->rt_flags &= ~RTF_REJECT; 893 return; 894 } 895 rtrequest(RTM_DELETE, rt_key(rt), (struct sockaddr *)0, rt_mask(rt), 896 0, (struct rtentry **)0); 897 } 898 /* 899 * Lookup or enter a new address in arptab. 900 */ 901 static struct llinfo_arp * 902 arplookup(addr, create, proxy) 903 u_long addr; 904 int create, proxy; 905 { 906 register struct rtentry *rt; 907 static struct sockaddr_inarp sin = {sizeof(sin), AF_INET }; 908 const char *why = 0; 909 910 sin.sin_addr.s_addr = addr; 911 sin.sin_other = proxy ? SIN_PROXY : 0; 912 rt = rtalloc1((struct sockaddr *)&sin, create, 0UL); 913 if (rt == 0) 914 return (0); 915 rt->rt_refcnt--; 916 917 if (rt->rt_flags & RTF_GATEWAY) 918 why = "host is not on local network"; 919 else if ((rt->rt_flags & RTF_LLINFO) == 0) 920 why = "could not allocate llinfo"; 921 else if (rt->rt_gateway->sa_family != AF_LINK) 922 why = "gateway route is not ours"; 923 924 if (why) { 925 if (create) 926 log(LOG_DEBUG, "arplookup %s failed: %s\n", 927 inet_ntoa(sin.sin_addr), why); 928 929 /* If there are no references to this route, purge it */ 930 if (rt->rt_refcnt <= 0 && 931 (rt->rt_flags & RTF_WASCLONED) == RTF_WASCLONED) { 932 rtrequest(RTM_DELETE, 933 (struct sockaddr *)rt_key(rt), 934 rt->rt_gateway, rt_mask(rt), 935 rt->rt_flags, 0); 936 } 937 return (0); 938 } 939 return ((struct llinfo_arp *)rt->rt_llinfo); 940 } 941 942 void 943 arp_ifinit(ifp, ifa) 944 struct ifnet *ifp; 945 struct ifaddr *ifa; 946 { 947 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY) 948 arprequest(ifp, &IA_SIN(ifa)->sin_addr, 949 &IA_SIN(ifa)->sin_addr, IF_LLADDR(ifp)); 950 ifa->ifa_rtrequest = arp_rtrequest; 951 ifa->ifa_flags |= RTF_CLONING; 952 } 953 954 static void 955 arp_init(void) 956 { 957 958 arpintrq.ifq_maxlen = 50; 959 mtx_init(&arpintrq.ifq_mtx, "arp_inq", NULL, MTX_DEF); 960 LIST_INIT(&llinfo_arp); 961 register_netisr(NETISR_ARP, arpintr); 962 } 963 964 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0);
Cache object: 22a6f376fe5dacd4b8714e92b3f85f7b
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