if_ether.c revision 109409
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: head/sys/netinet/if_ether.c 109409 2003-01-17 07:59:35Z hsu $ 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 79SYSCTL_DECL(_net_link_ether); 80SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, ""); 81 82/* timer values */ 83static int arpt_prune = (5*60*1); /* walk list every 5 minutes */ 84static int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */ 85static int arpt_down = 20; /* once declared down, don't send for 20 sec */ 86 87SYSCTL_INT(_net_link_ether_inet, OID_AUTO, prune_intvl, CTLFLAG_RW, 88 &arpt_prune, 0, ""); 89SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW, 90 &arpt_keep, 0, ""); 91SYSCTL_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 96struct 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 104static LIST_HEAD(, llinfo_arp) llinfo_arp; 105 106struct ifqueue arpintrq; 107static int arp_inuse, arp_allocated, arpinit_done; 108 109static int arp_maxtries = 5; 110static int useloopback = 1; /* use loopback interface for local traffic */ 111static int arp_proxyall = 0; 112 113SYSCTL_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW, 114 &arp_maxtries, 0, ""); 115SYSCTL_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW, 116 &useloopback, 0, ""); 117SYSCTL_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW, 118 &arp_proxyall, 0, ""); 119 120static void arp_init(void); 121static void arp_rtrequest(int, struct rtentry *, struct rt_addrinfo *); 122static void arprequest(struct ifnet *, 123 struct in_addr *, struct in_addr *, u_char *); 124static void arpintr(void); 125static void arptfree(struct llinfo_arp *); 126static void arptimer(void *); 127static struct llinfo_arp 128 *arplookup(u_long, int, int); 129#ifdef INET 130static void in_arpinput(struct mbuf *); 131#endif 132 133static struct mtx arp_mtx; 134 135#define ARP_LOCK_INIT() \ 136 mtx_init(&arp_mtx, "arp mutex", NULL, MTX_DEF | MTX_RECURSE) 137#define ARP_LOCK() mtx_lock(&arp_mtx) 138#define ARP_UNLOCK() mtx_unlock(&arp_mtx) 139 140/* 141 * Timeout routine. Age arp_tab entries periodically. 142 */ 143/* ARGSUSED */ 144static void 145arptimer(ignored_arg) 146 void *ignored_arg; 147{ 148 struct llinfo_arp *la, *ola; 149 int s = splnet(); 150 151 ARP_LOCK(); 152 la = LIST_FIRST(&llinfo_arp); 153 timeout(arptimer, NULL, arpt_prune * hz); 154 while (la != NULL) { 155 struct rtentry *rt = la->la_rt; 156 ola = la; 157 la = LIST_NEXT(la, la_le); 158 if (rt->rt_expire && rt->rt_expire <= time_second) 159 arptfree(ola); /* timer has expired, clear */ 160 } 161 ARP_UNLOCK(); 162 splx(s); 163} 164 165/* 166 * Parallel to llc_rtrequest. 167 */ 168static void 169arp_rtrequest(req, rt, info) 170 int req; 171 register struct rtentry *rt; 172 struct rt_addrinfo *info; 173{ 174 register struct sockaddr *gate = rt->rt_gateway; 175 register struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo; 176 static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK}; 177 178 if (!arpinit_done) { 179 arpinit_done = 1; 180 timeout(arptimer, (caddr_t)0, hz); 181 } 182 if (rt->rt_flags & RTF_GATEWAY) 183 return; 184 switch (req) { 185 186 case RTM_ADD: 187 /* 188 * XXX: If this is a manually added route to interface 189 * such as older version of routed or gated might provide, 190 * restore cloning bit. 191 */ 192 if ((rt->rt_flags & RTF_HOST) == 0 && 193 SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff) 194 rt->rt_flags |= RTF_CLONING; 195 if (rt->rt_flags & RTF_CLONING) { 196 /* 197 * Case 1: This route should come from a route to iface. 198 */ 199 rt_setgate(rt, rt_key(rt), 200 (struct sockaddr *)&null_sdl); 201 gate = rt->rt_gateway; 202 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 203 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 204 rt->rt_expire = time_second; 205 break; 206 } 207 /* Announce a new entry if requested. */ 208 if (rt->rt_flags & RTF_ANNOUNCE) 209 arprequest(rt->rt_ifp, 210 &SIN(rt_key(rt))->sin_addr, 211 &SIN(rt_key(rt))->sin_addr, 212 (u_char *)LLADDR(SDL(gate))); 213 /*FALLTHROUGH*/ 214 case RTM_RESOLVE: 215 if (gate->sa_family != AF_LINK || 216 gate->sa_len < sizeof(null_sdl)) { 217 log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n"); 218 break; 219 } 220 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 221 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 222 if (la != 0) 223 break; /* This happens on a route change */ 224 /* 225 * Case 2: This route may come from cloning, or a manual route 226 * add with a LL address. 227 */ 228 R_Malloc(la, struct llinfo_arp *, sizeof(*la)); 229 rt->rt_llinfo = (caddr_t)la; 230 if (la == 0) { 231 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); 232 break; 233 } 234 arp_inuse++, arp_allocated++; 235 Bzero(la, sizeof(*la)); 236 la->la_rt = rt; 237 rt->rt_flags |= RTF_LLINFO; 238 ARP_LOCK(); 239 LIST_INSERT_HEAD(&llinfo_arp, la, la_le); 240 ARP_UNLOCK(); 241 242#ifdef INET 243 /* 244 * This keeps the multicast addresses from showing up 245 * in `arp -a' listings as unresolved. It's not actually 246 * functional. Then the same for broadcast. 247 */ 248 if (IN_MULTICAST(ntohl(SIN(rt_key(rt))->sin_addr.s_addr)) && 249 rt->rt_ifp->if_type != IFT_ARCNET) { 250 ETHER_MAP_IP_MULTICAST(&SIN(rt_key(rt))->sin_addr, 251 LLADDR(SDL(gate))); 252 SDL(gate)->sdl_alen = 6; 253 rt->rt_expire = 0; 254 } 255 if (in_broadcast(SIN(rt_key(rt))->sin_addr, rt->rt_ifp)) { 256 memcpy(LLADDR(SDL(gate)), rt->rt_ifp->if_broadcastaddr, 257 rt->rt_ifp->if_addrlen); 258 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen; 259 rt->rt_expire = 0; 260 } 261#endif 262 263 if (SIN(rt_key(rt))->sin_addr.s_addr == 264 (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) { 265 /* 266 * This test used to be 267 * if (loif.if_flags & IFF_UP) 268 * It allowed local traffic to be forced 269 * through the hardware by configuring the loopback down. 270 * However, it causes problems during network configuration 271 * for boards that can't receive packets they send. 272 * It is now necessary to clear "useloopback" and remove 273 * the route to force traffic out to the hardware. 274 */ 275 rt->rt_expire = 0; 276 Bcopy(IF_LLADDR(rt->rt_ifp), LLADDR(SDL(gate)), 277 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen); 278 if (useloopback) 279 rt->rt_ifp = loif; 280 281 } 282 break; 283 284 case RTM_DELETE: 285 if (la == 0) 286 break; 287 arp_inuse--; 288 ARP_LOCK(); 289 LIST_REMOVE(la, la_le); 290 ARP_UNLOCK(); 291 rt->rt_llinfo = 0; 292 rt->rt_flags &= ~RTF_LLINFO; 293 if (la->la_hold) 294 m_freem(la->la_hold); 295 Free((caddr_t)la); 296 } 297} 298 299/* 300 * Broadcast an ARP request. Caller specifies: 301 * - arp header source ip address 302 * - arp header target ip address 303 * - arp header source ethernet address 304 */ 305static void 306arprequest(ifp, sip, tip, enaddr) 307 register struct ifnet *ifp; 308 register struct in_addr *sip, *tip; 309 register u_char *enaddr; 310{ 311 register struct mbuf *m; 312 register struct ether_header *eh; 313 register struct arc_header *arh; 314 register struct arphdr *ah; 315 struct sockaddr sa; 316 static u_char llcx[] = { 0x82, 0x40, LLC_SNAP_LSAP, LLC_SNAP_LSAP, 317 LLC_UI, 0x00, 0x00, 0x00, 0x08, 0x06 }; 318 u_short ar_hrd; 319 320 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 321 return; 322 m->m_pkthdr.rcvif = (struct ifnet *)0; 323#ifdef MAC 324 mac_create_mbuf_linklayer(ifp, m); 325#endif 326 switch (ifp->if_type) { 327 case IFT_ARCNET: 328 ar_hrd = htons(ARPHRD_ARCNET); 329 330 m->m_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 331 m->m_pkthdr.len = m->m_len; 332 MH_ALIGN(m, m->m_len); 333 334 arh = (struct arc_header *)sa.sa_data; 335 arh->arc_dhost = *ifp->if_broadcastaddr; 336 arh->arc_type = ARCTYPE_ARP; 337 338 ah = mtod(m, struct arphdr *); 339 break; 340 341 case IFT_ISO88025: 342 ar_hrd = htons(ARPHRD_IEEE802); 343 344 m->m_len = sizeof(llcx) + 345 arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 346 m->m_pkthdr.len = m->m_len; 347 MH_ALIGN(m, m->m_len); 348 349 (void)memcpy(mtod(m, caddr_t), llcx, sizeof(llcx)); 350 (void)memcpy(sa.sa_data, ifp->if_broadcastaddr, 6); 351 (void)memcpy(sa.sa_data + 6, enaddr, 6); 352 sa.sa_data[6] |= TR_RII; 353 sa.sa_data[12] = TR_AC; 354 sa.sa_data[13] = TR_LLC_FRAME; 355 356 ah = (struct arphdr *)(mtod(m, char *) + sizeof(llcx)); 357 break; 358 case IFT_FDDI: 359 case IFT_ETHER: 360 /* 361 * This may not be correct for types not explicitly 362 * listed, but this is our best guess 363 */ 364 default: 365 ar_hrd = htons(ARPHRD_ETHER); 366 367 m->m_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 368 m->m_pkthdr.len = m->m_len; 369 MH_ALIGN(m, m->m_len); 370 371 eh = (struct ether_header *)sa.sa_data; 372 /* if_output will not swap */ 373 eh->ether_type = htons(ETHERTYPE_ARP); 374 (void)memcpy(eh->ether_dhost, ifp->if_broadcastaddr, 375 sizeof(eh->ether_dhost)); 376 377 ah = mtod(m, struct arphdr *); 378 break; 379 } 380 381 ah->ar_hrd = ar_hrd; 382 ah->ar_pro = htons(ETHERTYPE_IP); 383 ah->ar_hln = ifp->if_addrlen; /* hardware address length */ 384 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 385 ah->ar_op = htons(ARPOP_REQUEST); 386 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln); 387 memset(ar_tha(ah), 0, ah->ar_hln); 388 (void)memcpy(ar_spa(ah), sip, ah->ar_pln); 389 (void)memcpy(ar_tpa(ah), tip, ah->ar_pln); 390 391 sa.sa_family = AF_UNSPEC; 392 sa.sa_len = sizeof(sa); 393 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 394} 395 396/* 397 * Resolve an IP address into an ethernet address. If success, 398 * desten is filled in. If there is no entry in arptab, 399 * set one up and broadcast a request for the IP address. 400 * Hold onto this mbuf and resend it once the address 401 * is finally resolved. A return value of 1 indicates 402 * that desten has been filled in and the packet should be sent 403 * normally; a 0 return indicates that the packet has been 404 * taken over here, either now or for later transmission. 405 */ 406int 407arpresolve(ifp, rt, m, dst, desten, rt0) 408 register struct ifnet *ifp; 409 register struct rtentry *rt; 410 struct mbuf *m; 411 register struct sockaddr *dst; 412 register u_char *desten; 413 struct rtentry *rt0; 414{ 415 struct llinfo_arp *la = 0; 416 struct sockaddr_dl *sdl; 417 418 if (m->m_flags & M_BCAST) { /* broadcast */ 419 (void)memcpy(desten, ifp->if_broadcastaddr, ifp->if_addrlen); 420 return (1); 421 } 422 if (m->m_flags & M_MCAST && ifp->if_type != IFT_ARCNET) {/* multicast */ 423 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); 424 return(1); 425 } 426 if (rt) 427 la = (struct llinfo_arp *)rt->rt_llinfo; 428 if (la == 0) { 429 la = arplookup(SIN(dst)->sin_addr.s_addr, 1, 0); 430 if (la) 431 rt = la->la_rt; 432 } 433 if (la == 0 || rt == 0) { 434 log(LOG_DEBUG, "arpresolve: can't allocate llinfo for %s%s%s\n", 435 inet_ntoa(SIN(dst)->sin_addr), la ? "la" : "", 436 rt ? "rt" : ""); 437 m_freem(m); 438 return (0); 439 } 440 sdl = SDL(rt->rt_gateway); 441 /* 442 * Check the address family and length is valid, the address 443 * is resolved; otherwise, try to resolve. 444 */ 445 if ((rt->rt_expire == 0 || rt->rt_expire > time_second) && 446 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 447 /* 448 * If entry has an expiry time and it is approaching, 449 * see if we need to send an ARP request within this 450 * arpt_down interval. 451 */ 452 if ((rt->rt_expire != 0) && 453 (time_second + (arp_maxtries - la->la_asked) * arpt_down > 454 rt->rt_expire)) { 455 arprequest(ifp, 456 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 457 &SIN(dst)->sin_addr, 458 IF_LLADDR(ifp)); 459 la->la_asked++; 460 } 461 462 bcopy(LLADDR(sdl), desten, sdl->sdl_alen); 463 return 1; 464 } 465 /* 466 * If ARP is disabled on this interface, stop. 467 * XXX 468 * Probably should not allocate empty llinfo struct if we are 469 * not going to be sending out an arp request. 470 */ 471 if (ifp->if_flags & IFF_NOARP) { 472 m_freem(m); 473 return (0); 474 } 475 /* 476 * There is an arptab entry, but no ethernet address 477 * response yet. Replace the held mbuf with this 478 * latest one. 479 */ 480 if (la->la_hold) 481 m_freem(la->la_hold); 482 la->la_hold = m; 483 if (rt->rt_expire) { 484 rt->rt_flags &= ~RTF_REJECT; 485 if (la->la_asked == 0 || rt->rt_expire != time_second) { 486 rt->rt_expire = time_second; 487 if (la->la_asked++ < arp_maxtries) 488 arprequest(ifp, 489 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 490 &SIN(dst)->sin_addr, 491 IF_LLADDR(ifp)); 492 else { 493 rt->rt_flags |= RTF_REJECT; 494 rt->rt_expire += arpt_down; 495 la->la_asked = 0; 496 } 497 498 } 499 } 500 return (0); 501} 502 503/* 504 * Common length and type checks are done here, 505 * then the protocol-specific routine is called. 506 */ 507static void 508arpintr() 509{ 510 register struct mbuf *m; 511 register struct arphdr *ar; 512 int s; 513 514 if (!arpinit_done) { 515 arpinit_done = 1; 516 timeout(arptimer, (caddr_t)0, hz); 517 } 518 while (arpintrq.ifq_head) { 519 s = splimp(); 520 IF_DEQUEUE(&arpintrq, m); 521 splx(s); 522 if (m == 0 || (m->m_flags & M_PKTHDR) == 0) 523 panic("arpintr"); 524 525 if (m->m_len < sizeof(struct arphdr) && 526 ((m = m_pullup(m, sizeof(struct arphdr))) == NULL)) { 527 log(LOG_ERR, "arp: runt packet -- m_pullup failed\n"); 528 continue; 529 } 530 ar = mtod(m, struct arphdr *); 531 532 if (ntohs(ar->ar_hrd) != ARPHRD_ETHER 533 && ntohs(ar->ar_hrd) != ARPHRD_IEEE802 534 && ntohs(ar->ar_hrd) != ARPHRD_ARCNET) { 535 log(LOG_ERR, 536 "arp: unknown hardware address format (0x%2D)\n", 537 (unsigned char *)&ar->ar_hrd, ""); 538 m_freem(m); 539 continue; 540 } 541 542 if (m->m_pkthdr.len < arphdr_len(ar) && 543 (m = m_pullup(m, arphdr_len(ar))) == NULL) { 544 log(LOG_ERR, "arp: runt packet\n"); 545 m_freem(m); 546 continue; 547 } 548 549 switch (ntohs(ar->ar_pro)) { 550#ifdef INET 551 case ETHERTYPE_IP: 552 in_arpinput(m); 553 continue; 554#endif 555 } 556 m_freem(m); 557 } 558} 559 560#ifdef INET 561/* 562 * ARP for Internet protocols on 10 Mb/s Ethernet. 563 * Algorithm is that given in RFC 826. 564 * In addition, a sanity check is performed on the sender 565 * protocol address, to catch impersonators. 566 * We no longer handle negotiations for use of trailer protocol: 567 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 568 * along with IP replies if we wanted trailers sent to us, 569 * and also sent them in response to IP replies. 570 * This allowed either end to announce the desire to receive 571 * trailer packets. 572 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 573 * but formerly didn't normally send requests. 574 */ 575static int log_arp_wrong_iface = 1; 576static int log_arp_movements = 1; 577 578SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW, 579 &log_arp_wrong_iface, 0, 580 "log arp packets arriving on the wrong interface"); 581SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_movements, CTLFLAG_RW, 582 &log_arp_movements, 0, 583 "log arp replies from MACs different than the one in the cache"); 584 585 586static void 587in_arpinput(m) 588 struct mbuf *m; 589{ 590 register struct arphdr *ah; 591 register struct ifnet *ifp = m->m_pkthdr.rcvif; 592 struct ether_header *eh; 593 struct arc_header *arh; 594 struct iso88025_header *th = (struct iso88025_header *)0; 595 struct iso88025_sockaddr_dl_data *trld; 596 register struct llinfo_arp *la = 0; 597 register struct rtentry *rt; 598 struct ifaddr *ifa; 599 struct in_ifaddr *ia; 600 struct sockaddr_dl *sdl; 601 struct sockaddr sa; 602 struct in_addr isaddr, itaddr, myaddr; 603 int op, rif_len; 604 int req_len; 605 606 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 607 if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) { 608 log(LOG_ERR, "in_arp: runt packet -- m_pullup failed\n"); 609 return; 610 } 611 612 ah = mtod(m, struct arphdr *); 613 op = ntohs(ah->ar_op); 614 (void)memcpy(&isaddr, ar_spa(ah), sizeof (isaddr)); 615 (void)memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr)); 616#ifdef BRIDGE 617#define BRIDGE_TEST (do_bridge) 618#else 619#define BRIDGE_TEST (0) /* cc will optimise the test away */ 620#endif 621 /* 622 * For a bridge, we want to check the address irrespective 623 * of the receive interface. (This will change slightly 624 * when we have clusters of interfaces). 625 */ 626 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) 627 if ((BRIDGE_TEST || (ia->ia_ifp == ifp)) && 628 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) 629 goto match; 630 LIST_FOREACH(ia, INADDR_HASH(isaddr.s_addr), ia_hash) 631 if ((BRIDGE_TEST || (ia->ia_ifp == ifp)) && 632 isaddr.s_addr == ia->ia_addr.sin_addr.s_addr) 633 goto match; 634 /* 635 * No match, use the first inet address on the receive interface 636 * as a dummy address for the rest of the function. 637 */ 638 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) 639 if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_INET) { 640 ia = ifatoia(ifa); 641 goto match; 642 } 643 /* 644 * If bridging, fall back to using any inet address. 645 */ 646 if (!BRIDGE_TEST || 647 (ia = TAILQ_FIRST(&in_ifaddrhead)) == NULL) { 648 m_freem(m); 649 return; 650 } 651match: 652 myaddr = ia->ia_addr.sin_addr; 653 if (!bcmp(ar_sha(ah), IF_LLADDR(ifp), ifp->if_addrlen)) { 654 m_freem(m); /* it's from me, ignore it. */ 655 return; 656 } 657 if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) { 658 log(LOG_ERR, 659 "arp: link address is broadcast for IP address %s!\n", 660 inet_ntoa(isaddr)); 661 m_freem(m); 662 return; 663 } 664 if (isaddr.s_addr == myaddr.s_addr) { 665 log(LOG_ERR, 666 "arp: %*D is using my IP address %s!\n", 667 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 668 inet_ntoa(isaddr)); 669 itaddr = myaddr; 670 goto reply; 671 } 672 la = arplookup(isaddr.s_addr, itaddr.s_addr == myaddr.s_addr, 0); 673 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { 674 /* the following is not an error when doing bridging */ 675 if (!BRIDGE_TEST && rt->rt_ifp != ifp) { 676 if (log_arp_wrong_iface) 677 log(LOG_ERR, "arp: %s is on %s%d but got reply from %*D on %s%d\n", 678 inet_ntoa(isaddr), 679 rt->rt_ifp->if_name, rt->rt_ifp->if_unit, 680 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 681 ifp->if_name, ifp->if_unit); 682 goto reply; 683 } 684 if (sdl->sdl_alen && 685 bcmp(ar_sha(ah), LLADDR(sdl), sdl->sdl_alen)) { 686 if (rt->rt_expire) { 687 if (log_arp_movements) 688 log(LOG_INFO, "arp: %s moved from %*D to %*D on %s%d\n", 689 inet_ntoa(isaddr), 690 ifp->if_addrlen, (u_char *)LLADDR(sdl), ":", 691 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 692 ifp->if_name, ifp->if_unit); 693 } else { 694 log(LOG_ERR, 695 "arp: %*D attempts to modify permanent entry for %s on %s%d\n", 696 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 697 inet_ntoa(isaddr), ifp->if_name, ifp->if_unit); 698 goto reply; 699 } 700 } 701 /* 702 * sanity check for the address length. 703 * XXX this does not work for protocols with variable address 704 * length. -is 705 */ 706 if (sdl->sdl_alen && 707 sdl->sdl_alen != ah->ar_hln) { 708 log(LOG_WARNING, 709 "arp from %*D: new addr len %d, was %d", 710 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 711 ah->ar_hln, sdl->sdl_alen); 712 } 713 if (ifp->if_addrlen != ah->ar_hln) { 714 log(LOG_WARNING, 715 "arp from %*D: addr len: new %d, i/f %d (ignored)", 716 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 717 ah->ar_hln, ifp->if_addrlen); 718 goto reply; 719 } 720 (void)memcpy(LLADDR(sdl), ar_sha(ah), 721 sdl->sdl_alen = ah->ar_hln); 722 /* 723 * If we receive an arp from a token-ring station over 724 * a token-ring nic then try to save the source 725 * routing info. 726 */ 727 if (ifp->if_type == IFT_ISO88025) { 728 th = (struct iso88025_header *)m->m_pkthdr.header; 729 trld = SDL_ISO88025(sdl); 730 rif_len = TR_RCF_RIFLEN(th->rcf); 731 if ((th->iso88025_shost[0] & TR_RII) && 732 (rif_len > 2)) { 733 trld->trld_rcf = th->rcf; 734 trld->trld_rcf ^= htons(TR_RCF_DIR); 735 memcpy(trld->trld_route, th->rd, rif_len - 2); 736 trld->trld_rcf &= ~htons(TR_RCF_BCST_MASK); 737 /* 738 * Set up source routing information for 739 * reply packet (XXX) 740 */ 741 m->m_data -= rif_len; 742 m->m_len += rif_len; 743 m->m_pkthdr.len += rif_len; 744 } else { 745 th->iso88025_shost[0] &= ~TR_RII; 746 trld->trld_rcf = 0; 747 } 748 m->m_data -= 8; 749 m->m_len += 8; 750 m->m_pkthdr.len += 8; 751 th->rcf = trld->trld_rcf; 752 } 753 if (rt->rt_expire) 754 rt->rt_expire = time_second + arpt_keep; 755 rt->rt_flags &= ~RTF_REJECT; 756 la->la_asked = 0; 757 if (la->la_hold) { 758 (*ifp->if_output)(ifp, la->la_hold, 759 rt_key(rt), rt); 760 la->la_hold = 0; 761 } 762 } 763reply: 764 if (op != ARPOP_REQUEST) { 765 m_freem(m); 766 return; 767 } 768 if (itaddr.s_addr == myaddr.s_addr) { 769 /* I am the target */ 770 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 771 (void)memcpy(ar_sha(ah), IF_LLADDR(ifp), ah->ar_hln); 772 } else { 773 la = arplookup(itaddr.s_addr, 0, SIN_PROXY); 774 if (la == NULL) { 775 struct sockaddr_in sin; 776 777 if (!arp_proxyall) { 778 m_freem(m); 779 return; 780 } 781 782 bzero(&sin, sizeof sin); 783 sin.sin_family = AF_INET; 784 sin.sin_len = sizeof sin; 785 sin.sin_addr = itaddr; 786 787 rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL); 788 if (!rt) { 789 m_freem(m); 790 return; 791 } 792 /* 793 * Don't send proxies for nodes on the same interface 794 * as this one came out of, or we'll get into a fight 795 * over who claims what Ether address. 796 */ 797 if (rt->rt_ifp == ifp) { 798 rtfree(rt); 799 m_freem(m); 800 return; 801 } 802 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 803 (void)memcpy(ar_sha(ah), IF_LLADDR(ifp), ah->ar_hln); 804 rtfree(rt); 805 806 /* 807 * Also check that the node which sent the ARP packet 808 * is on the the interface we expect it to be on. This 809 * avoids ARP chaos if an interface is connected to the 810 * wrong network. 811 */ 812 sin.sin_addr = isaddr; 813 814 rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL); 815 if (!rt) { 816 m_freem(m); 817 return; 818 } 819 if (rt->rt_ifp != ifp) { 820 log(LOG_INFO, "arp_proxy: ignoring request" 821 " from %s via %s%d, expecting %s%d\n", 822 inet_ntoa(isaddr), ifp->if_name, 823 ifp->if_unit, rt->rt_ifp->if_name, 824 rt->rt_ifp->if_unit); 825 rtfree(rt); 826 m_freem(m); 827 return; 828 } 829 rtfree(rt); 830 831#ifdef DEBUG_PROXY 832 printf("arp: proxying for %s\n", 833 inet_ntoa(itaddr)); 834#endif 835 } else { 836 rt = la->la_rt; 837 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 838 sdl = SDL(rt->rt_gateway); 839 (void)memcpy(ar_sha(ah), LLADDR(sdl), ah->ar_hln); 840 } 841 } 842 843 (void)memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln); 844 (void)memcpy(ar_spa(ah), &itaddr, ah->ar_pln); 845 ah->ar_op = htons(ARPOP_REPLY); 846 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 847 switch (ifp->if_type) { 848 case IFT_ARCNET: 849 arh = (struct arc_header *)sa.sa_data; 850 arh->arc_dhost = *ar_tha(ah); 851 arh->arc_type = ARCTYPE_ARP; 852 break; 853 854 case IFT_ISO88025: 855 /* Re-arrange the source/dest address */ 856 memcpy(th->iso88025_dhost, th->iso88025_shost, 857 sizeof(th->iso88025_dhost)); 858 memcpy(th->iso88025_shost, IF_LLADDR(ifp), 859 sizeof(th->iso88025_shost)); 860 /* Set the source routing bit if neccesary */ 861 if (th->iso88025_dhost[0] & TR_RII) { 862 th->iso88025_dhost[0] &= ~TR_RII; 863 if (TR_RCF_RIFLEN(th->rcf) > 2) 864 th->iso88025_shost[0] |= TR_RII; 865 } 866 /* Copy the addresses, ac and fc into sa_data */ 867 memcpy(sa.sa_data, th->iso88025_dhost, 868 sizeof(th->iso88025_dhost) * 2); 869 sa.sa_data[(sizeof(th->iso88025_dhost) * 2)] = TR_AC; 870 sa.sa_data[(sizeof(th->iso88025_dhost) * 2) + 1] = TR_LLC_FRAME; 871 break; 872 case IFT_ETHER: 873 case IFT_FDDI: 874 /* 875 * May not be correct for types not explictly 876 * listed, but it is our best guess. 877 */ 878 default: 879 eh = (struct ether_header *)sa.sa_data; 880 (void)memcpy(eh->ether_dhost, ar_tha(ah), 881 sizeof(eh->ether_dhost)); 882 eh->ether_type = htons(ETHERTYPE_ARP); 883 break; 884 } 885 sa.sa_family = AF_UNSPEC; 886 sa.sa_len = sizeof(sa); 887 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 888 return; 889} 890#endif 891 892/* 893 * Free an arp entry. 894 */ 895static void 896arptfree(la) 897 register struct llinfo_arp *la; 898{ 899 register struct rtentry *rt = la->la_rt; 900 register struct sockaddr_dl *sdl; 901 if (rt == 0) 902 panic("arptfree"); 903 if (rt->rt_refcnt > 0 && (sdl = SDL(rt->rt_gateway)) && 904 sdl->sdl_family == AF_LINK) { 905 sdl->sdl_alen = 0; 906 la->la_asked = 0; 907 rt->rt_flags &= ~RTF_REJECT; 908 return; 909 } 910 rtrequest(RTM_DELETE, rt_key(rt), (struct sockaddr *)0, rt_mask(rt), 911 0, (struct rtentry **)0); 912} 913/* 914 * Lookup or enter a new address in arptab. 915 */ 916static struct llinfo_arp * 917arplookup(addr, create, proxy) 918 u_long addr; 919 int create, proxy; 920{ 921 register struct rtentry *rt; 922 static struct sockaddr_inarp sin = {sizeof(sin), AF_INET }; 923 const char *why = 0; 924 925 sin.sin_addr.s_addr = addr; 926 sin.sin_other = proxy ? SIN_PROXY : 0; 927 rt = rtalloc1((struct sockaddr *)&sin, create, 0UL); 928 if (rt == 0) 929 return (0); 930 rt->rt_refcnt--; 931 932 if (rt->rt_flags & RTF_GATEWAY) 933 why = "host is not on local network"; 934 else if ((rt->rt_flags & RTF_LLINFO) == 0) 935 why = "could not allocate llinfo"; 936 else if (rt->rt_gateway->sa_family != AF_LINK) 937 why = "gateway route is not ours"; 938 939 if (why && create) { 940 log(LOG_DEBUG, "arplookup %s failed: %s\n", 941 inet_ntoa(sin.sin_addr), why); 942 return 0; 943 } else if (why) { 944 return 0; 945 } 946 return ((struct llinfo_arp *)rt->rt_llinfo); 947} 948 949void 950arp_ifinit(ifp, ifa) 951 struct ifnet *ifp; 952 struct ifaddr *ifa; 953{ 954 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY) 955 arprequest(ifp, &IA_SIN(ifa)->sin_addr, 956 &IA_SIN(ifa)->sin_addr, IF_LLADDR(ifp)); 957 ifa->ifa_rtrequest = arp_rtrequest; 958 ifa->ifa_flags |= RTF_CLONING; 959} 960 961static void 962arp_init(void) 963{ 964 965 arpintrq.ifq_maxlen = 50; 966 mtx_init(&arpintrq.ifq_mtx, "arp_inq", NULL, MTX_DEF); 967 LIST_INIT(&llinfo_arp); 968 ARP_LOCK_INIT(); 969 register_netisr(NETISR_ARP, arpintr); 970} 971 972SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0); 973