if_ether.c revision 85074
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 85074 2001-10-17 18:07:05Z ru $ 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 46#include <sys/param.h> 47#include <sys/kernel.h> 48#include <sys/queue.h> 49#include <sys/sysctl.h> 50#include <sys/systm.h> 51#include <sys/mbuf.h> 52#include <sys/malloc.h> 53#include <sys/socket.h> 54#include <sys/syslog.h> 55 56#include <net/if.h> 57#include <net/if_dl.h> 58#include <net/if_types.h> 59#include <net/route.h> 60#include <net/netisr.h> 61#include <net/if_llc.h> 62#ifdef BRIDGE 63#include <net/ethernet.h> 64#include <net/bridge.h> 65#endif 66 67#include <netinet/in.h> 68#include <netinet/in_var.h> 69#include <netinet/if_ether.h> 70 71#include <net/if_arc.h> 72#include <net/iso88025.h> 73 74#define SIN(s) ((struct sockaddr_in *)s) 75#define SDL(s) ((struct sockaddr_dl *)s) 76 77SYSCTL_DECL(_net_link_ether); 78SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, ""); 79 80/* timer values */ 81static int arpt_prune = (5*60*1); /* walk list every 5 minutes */ 82static int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */ 83static int arpt_down = 20; /* once declared down, don't send for 20 sec */ 84 85SYSCTL_INT(_net_link_ether_inet, OID_AUTO, prune_intvl, CTLFLAG_RW, 86 &arpt_prune, 0, ""); 87SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW, 88 &arpt_keep, 0, ""); 89SYSCTL_INT(_net_link_ether_inet, OID_AUTO, host_down_time, CTLFLAG_RW, 90 &arpt_down, 0, ""); 91 92#define rt_expire rt_rmx.rmx_expire 93 94struct llinfo_arp { 95 LIST_ENTRY(llinfo_arp) la_le; 96 struct rtentry *la_rt; 97 struct mbuf *la_hold; /* last packet until resolved/timeout */ 98 long la_asked; /* last time we QUERIED for this addr */ 99#define la_timer la_rt->rt_rmx.rmx_expire /* deletion time in seconds */ 100}; 101 102static LIST_HEAD(, llinfo_arp) llinfo_arp; 103 104struct ifqueue arpintrq; 105static int arp_inuse, arp_allocated; 106 107static int arp_maxtries = 5; 108static int useloopback = 1; /* use loopback interface for local traffic */ 109static int arp_proxyall = 0; 110 111SYSCTL_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW, 112 &arp_maxtries, 0, ""); 113SYSCTL_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW, 114 &useloopback, 0, ""); 115SYSCTL_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW, 116 &arp_proxyall, 0, ""); 117 118static void arp_init __P((void)); 119static void arp_rtrequest __P((int, struct rtentry *, struct rt_addrinfo *)); 120static void arprequest __P((struct ifnet *, 121 struct in_addr *, struct in_addr *, u_char *)); 122static void arpintr __P((void)); 123static void arptfree __P((struct llinfo_arp *)); 124static void arptimer __P((void *)); 125static struct llinfo_arp 126 *arplookup __P((u_long, int, int)); 127#ifdef INET 128static void in_arpinput __P((struct mbuf *)); 129#endif 130 131/* 132 * Timeout routine. Age arp_tab entries periodically. 133 */ 134/* ARGSUSED */ 135static void 136arptimer(ignored_arg) 137 void *ignored_arg; 138{ 139 int s = splnet(); 140 register struct llinfo_arp *la = LIST_FIRST(&llinfo_arp); 141 struct llinfo_arp *ola; 142 143 timeout(arptimer, (caddr_t)0, arpt_prune * hz); 144 while ((ola = la) != 0) { 145 register struct rtentry *rt = la->la_rt; 146 la = LIST_NEXT(la, la_le); 147 if (rt->rt_expire && rt->rt_expire <= time_second) 148 arptfree(ola); /* timer has expired, clear */ 149 } 150 splx(s); 151} 152 153/* 154 * Parallel to llc_rtrequest. 155 */ 156static void 157arp_rtrequest(req, rt, info) 158 int req; 159 register struct rtentry *rt; 160 struct rt_addrinfo *info; 161{ 162 register struct sockaddr *gate = rt->rt_gateway; 163 register struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo; 164 static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK}; 165 static int arpinit_done; 166 167 if (!arpinit_done) { 168 arpinit_done = 1; 169 LIST_INIT(&llinfo_arp); 170 timeout(arptimer, (caddr_t)0, hz); 171 register_netisr(NETISR_ARP, arpintr); 172 } 173 if (rt->rt_flags & RTF_GATEWAY) 174 return; 175 switch (req) { 176 177 case RTM_ADD: 178 /* 179 * XXX: If this is a manually added route to interface 180 * such as older version of routed or gated might provide, 181 * restore cloning bit. 182 */ 183 if ((rt->rt_flags & RTF_HOST) == 0 && 184 SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff) 185 rt->rt_flags |= RTF_CLONING; 186 if (rt->rt_flags & RTF_CLONING) { 187 /* 188 * Case 1: This route should come from a route to iface. 189 */ 190 rt_setgate(rt, rt_key(rt), 191 (struct sockaddr *)&null_sdl); 192 gate = rt->rt_gateway; 193 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 194 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 195 rt->rt_expire = time_second; 196 break; 197 } 198 /* Announce a new entry if requested. */ 199 if (rt->rt_flags & RTF_ANNOUNCE) 200 arprequest(rt->rt_ifp, 201 &SIN(rt_key(rt))->sin_addr, 202 &SIN(rt_key(rt))->sin_addr, 203 (u_char *)LLADDR(SDL(gate))); 204 /*FALLTHROUGH*/ 205 case RTM_RESOLVE: 206 if (gate->sa_family != AF_LINK || 207 gate->sa_len < sizeof(null_sdl)) { 208 log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n"); 209 break; 210 } 211 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 212 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 213 if (la != 0) 214 break; /* This happens on a route change */ 215 /* 216 * Case 2: This route may come from cloning, or a manual route 217 * add with a LL address. 218 */ 219 R_Malloc(la, struct llinfo_arp *, sizeof(*la)); 220 rt->rt_llinfo = (caddr_t)la; 221 if (la == 0) { 222 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); 223 break; 224 } 225 arp_inuse++, arp_allocated++; 226 Bzero(la, sizeof(*la)); 227 la->la_rt = rt; 228 rt->rt_flags |= RTF_LLINFO; 229 LIST_INSERT_HEAD(&llinfo_arp, la, la_le); 230 231#ifdef INET 232 /* 233 * This keeps the multicast addresses from showing up 234 * in `arp -a' listings as unresolved. It's not actually 235 * functional. Then the same for broadcast. 236 */ 237 if (IN_MULTICAST(ntohl(SIN(rt_key(rt))->sin_addr.s_addr)) 238 && rt->rt_ifp->if_type != IFT_ARCNET) { 239 ETHER_MAP_IP_MULTICAST(&SIN(rt_key(rt))->sin_addr, 240 LLADDR(SDL(gate))); 241 SDL(gate)->sdl_alen = 6; 242 rt->rt_expire = 0; 243 } 244 if (in_broadcast(SIN(rt_key(rt))->sin_addr, rt->rt_ifp)) { 245 memcpy(LLADDR(SDL(gate)), rt->rt_ifp->if_broadcastaddr, 246 rt->rt_ifp->if_addrlen); 247 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen; 248 rt->rt_expire = 0; 249 } 250#endif 251 252 if (SIN(rt_key(rt))->sin_addr.s_addr == 253 (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) { 254 /* 255 * This test used to be 256 * if (loif.if_flags & IFF_UP) 257 * It allowed local traffic to be forced 258 * through the hardware by configuring the loopback down. 259 * However, it causes problems during network configuration 260 * for boards that can't receive packets they send. 261 * It is now necessary to clear "useloopback" and remove 262 * the route to force traffic out to the hardware. 263 */ 264 rt->rt_expire = 0; 265 Bcopy(IF_LLADDR(rt->rt_ifp), LLADDR(SDL(gate)), 266 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen); 267 if (useloopback) 268 rt->rt_ifp = loif; 269 270 } 271 break; 272 273 case RTM_DELETE: 274 if (la == 0) 275 break; 276 arp_inuse--; 277 LIST_REMOVE(la, la_le); 278 rt->rt_llinfo = 0; 279 rt->rt_flags &= ~RTF_LLINFO; 280 if (la->la_hold) 281 m_freem(la->la_hold); 282 Free((caddr_t)la); 283 } 284} 285 286/* 287 * Broadcast an ARP request. Caller specifies: 288 * - arp header source ip address 289 * - arp header target ip address 290 * - arp header source ethernet address 291 */ 292static void 293arprequest(ifp, sip, tip, enaddr) 294 register struct ifnet *ifp; 295 register struct in_addr *sip, *tip; 296 register u_char *enaddr; 297{ 298 register struct mbuf *m; 299 register struct ether_header *eh; 300 register struct arc_header *arh; 301 register struct arphdr *ah; 302 struct sockaddr sa; 303 static u_char llcx[] = { 0x82, 0x40, LLC_SNAP_LSAP, LLC_SNAP_LSAP, 304 LLC_UI, 0x00, 0x00, 0x00, 0x08, 0x06 }; 305 u_short ar_hrd; 306 307 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 308 return; 309 m->m_pkthdr.rcvif = (struct ifnet *)0; 310 switch (ifp->if_type) { 311 case IFT_ARCNET: 312 ar_hrd = htons(ARPHRD_ARCNET); 313 314 m->m_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 315 m->m_pkthdr.len = m->m_len; 316 MH_ALIGN(m, m->m_len); 317 318 arh = (struct arc_header *)sa.sa_data; 319 arh->arc_dhost = *ifp->if_broadcastaddr; 320 arh->arc_type = ARCTYPE_ARP; 321 322 ah = mtod(m, struct arphdr *); 323 break; 324 325 case IFT_ISO88025: 326 ar_hrd = htons(ARPHRD_IEEE802); 327 328 m->m_len = sizeof(llcx) + 329 arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 330 m->m_pkthdr.len = m->m_len; 331 MH_ALIGN(m, m->m_len); 332 333 (void)memcpy(mtod(m, caddr_t), llcx, sizeof(llcx)); 334 (void)memcpy(sa.sa_data, ifp->if_broadcastaddr, 6); 335 (void)memcpy(sa.sa_data + 6, enaddr, 6); 336 sa.sa_data[6] |= TR_RII; 337 sa.sa_data[12] = TR_AC; 338 sa.sa_data[13] = TR_LLC_FRAME; 339 340 ah = (struct arphdr *)(mtod(m, char *) + sizeof(llcx)); 341 break; 342 case IFT_FDDI: 343 case IFT_ETHER: 344 /* 345 * This may not be correct for types not explicitly 346 * listed, but this is our best guess 347 */ 348 default: 349 ar_hrd = htons(ARPHRD_ETHER); 350 351 m->m_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 352 m->m_pkthdr.len = m->m_len; 353 MH_ALIGN(m, m->m_len); 354 355 eh = (struct ether_header *)sa.sa_data; 356 /* if_output will not swap */ 357 eh->ether_type = htons(ETHERTYPE_ARP); 358 (void)memcpy(eh->ether_dhost, ifp->if_broadcastaddr, 359 sizeof(eh->ether_dhost)); 360 361 ah = mtod(m, struct arphdr *); 362 break; 363 } 364 365 ah->ar_hrd = ar_hrd; 366 ah->ar_pro = htons(ETHERTYPE_IP); 367 ah->ar_hln = ifp->if_addrlen; /* hardware address length */ 368 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 369 ah->ar_op = htons(ARPOP_REQUEST); 370 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln); 371 (void)memcpy(ar_spa(ah), sip, ah->ar_pln); 372 (void)memcpy(ar_tpa(ah), tip, ah->ar_pln); 373 374 sa.sa_family = AF_UNSPEC; 375 sa.sa_len = sizeof(sa); 376 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 377} 378 379/* 380 * Resolve an IP address into an ethernet address. If success, 381 * desten is filled in. If there is no entry in arptab, 382 * set one up and broadcast a request for the IP address. 383 * Hold onto this mbuf and resend it once the address 384 * is finally resolved. A return value of 1 indicates 385 * that desten has been filled in and the packet should be sent 386 * normally; a 0 return indicates that the packet has been 387 * taken over here, either now or for later transmission. 388 */ 389int 390arpresolve(ifp, rt, m, dst, desten, rt0) 391 register struct ifnet *ifp; 392 register struct rtentry *rt; 393 struct mbuf *m; 394 register struct sockaddr *dst; 395 register u_char *desten; 396 struct rtentry *rt0; 397{ 398 struct llinfo_arp *la = 0; 399 struct sockaddr_dl *sdl; 400 401 if (m->m_flags & M_BCAST) { /* broadcast */ 402 (void)memcpy(desten, ifp->if_broadcastaddr, ifp->if_addrlen); 403 return (1); 404 } 405 if (m->m_flags & M_MCAST && ifp->if_type != IFT_ARCNET) {/* multicast */ 406 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); 407 return(1); 408 } 409 if (rt) 410 la = (struct llinfo_arp *)rt->rt_llinfo; 411 if (la == 0) { 412 la = arplookup(SIN(dst)->sin_addr.s_addr, 1, 0); 413 if (la) 414 rt = la->la_rt; 415 } 416 if (la == 0 || rt == 0) { 417 log(LOG_DEBUG, "arpresolve: can't allocate llinfo for %s%s%s\n", 418 inet_ntoa(SIN(dst)->sin_addr), la ? "la" : "", 419 rt ? "rt" : ""); 420 m_freem(m); 421 return (0); 422 } 423 sdl = SDL(rt->rt_gateway); 424 /* 425 * Check the address family and length is valid, the address 426 * is resolved; otherwise, try to resolve. 427 */ 428 if ((rt->rt_expire == 0 || rt->rt_expire > time_second) && 429 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 430 bcopy(LLADDR(sdl), desten, sdl->sdl_alen); 431 return 1; 432 } 433 /* 434 * If ARP is disabled on this interface, stop. 435 * XXX 436 * Probably should not allocate empty llinfo struct if we are 437 * not going to be sending out an arp request. 438 */ 439 if (ifp->if_flags & IFF_NOARP) 440 return (0); 441 /* 442 * There is an arptab entry, but no ethernet address 443 * response yet. Replace the held mbuf with this 444 * latest one. 445 */ 446 if (la->la_hold) 447 m_freem(la->la_hold); 448 la->la_hold = m; 449 if (rt->rt_expire) { 450 rt->rt_flags &= ~RTF_REJECT; 451 if (la->la_asked == 0 || rt->rt_expire != time_second) { 452 rt->rt_expire = time_second; 453 if (la->la_asked++ < arp_maxtries) 454 arprequest(ifp, 455 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 456 &SIN(dst)->sin_addr, 457 IF_LLADDR(ifp)); 458 else { 459 rt->rt_flags |= RTF_REJECT; 460 rt->rt_expire += arpt_down; 461 la->la_asked = 0; 462 } 463 464 } 465 } 466 return (0); 467} 468 469/* 470 * Common length and type checks are done here, 471 * then the protocol-specific routine is called. 472 */ 473static void 474arpintr() 475{ 476 register struct mbuf *m; 477 register struct arphdr *ar; 478 int s; 479 480 while (arpintrq.ifq_head) { 481 s = splimp(); 482 IF_DEQUEUE(&arpintrq, m); 483 splx(s); 484 if (m == 0 || (m->m_flags & M_PKTHDR) == 0) 485 panic("arpintr"); 486 487 if (m->m_len < sizeof(struct arphdr) && 488 ((m = m_pullup(m, sizeof(struct arphdr))) == NULL)) { 489 log(LOG_ERR, "arp: runt packet -- m_pullup failed\n"); 490 continue; 491 } 492 ar = mtod(m, struct arphdr *); 493 494 if (ntohs(ar->ar_hrd) != ARPHRD_ETHER 495 && ntohs(ar->ar_hrd) != ARPHRD_IEEE802 496 && ntohs(ar->ar_hrd) != ARPHRD_ARCNET) { 497 log(LOG_ERR, 498 "arp: unknown hardware address format (0x%2D)\n", 499 (unsigned char *)&ar->ar_hrd, ""); 500 m_freem(m); 501 continue; 502 } 503 504 if (m->m_pkthdr.len < arphdr_len(ar) && 505 (m = m_pullup(m, arphdr_len(ar))) == NULL) { 506 log(LOG_ERR, "arp: runt packet\n"); 507 m_freem(m); 508 continue; 509 } 510 511 switch (ntohs(ar->ar_pro)) { 512#ifdef INET 513 case ETHERTYPE_IP: 514 in_arpinput(m); 515 continue; 516#endif 517 } 518 m_freem(m); 519 } 520} 521 522#ifdef INET 523/* 524 * ARP for Internet protocols on 10 Mb/s Ethernet. 525 * Algorithm is that given in RFC 826. 526 * In addition, a sanity check is performed on the sender 527 * protocol address, to catch impersonators. 528 * We no longer handle negotiations for use of trailer protocol: 529 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 530 * along with IP replies if we wanted trailers sent to us, 531 * and also sent them in response to IP replies. 532 * This allowed either end to announce the desire to receive 533 * trailer packets. 534 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 535 * but formerly didn't normally send requests. 536 */ 537static int log_arp_wrong_iface = 1; 538static int log_arp_movements = 1; 539 540SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW, 541 &log_arp_wrong_iface, 0, 542 "log arp packets arriving on the wrong interface"); 543SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_movements, CTLFLAG_RW, 544 &log_arp_movements, 0, 545 "log arp replies from MACs different than the one in the cache"); 546 547 548static void 549in_arpinput(m) 550 struct mbuf *m; 551{ 552 register struct arphdr *ah; 553 register struct ifnet *ifp = m->m_pkthdr.rcvif; 554 struct ether_header *eh; 555 struct arc_header *arh; 556 struct iso88025_header *th = (struct iso88025_header *)0; 557 register struct llinfo_arp *la = 0; 558 register struct rtentry *rt; 559 struct ifaddr *ifa; 560 struct in_ifaddr *ia; 561 struct sockaddr_dl *sdl; 562 struct sockaddr sa; 563 struct in_addr isaddr, itaddr, myaddr; 564 int op, rif_len; 565 int req_len; 566 567 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 568 if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) { 569 log(LOG_ERR, "in_arp: runt packet -- m_pullup failed\n"); 570 return; 571 } 572 573 ah = mtod(m, struct arphdr *); 574 op = ntohs(ah->ar_op); 575 (void)memcpy(&isaddr, ar_spa(ah), sizeof (isaddr)); 576 (void)memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr)); 577#ifdef BRIDGE 578#define BRIDGE_TEST (do_bridge) 579#else 580#define BRIDGE_TEST (0) /* cc will optimise the test away */ 581#endif 582 /* 583 * For a bridge, we want to check the address irrespective 584 * of the receive interface. (This will change slightly 585 * when we have clusters of interfaces). 586 */ 587 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) 588 if ((BRIDGE_TEST || (ia->ia_ifp == ifp)) && 589 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) 590 goto match; 591 LIST_FOREACH(ia, INADDR_HASH(isaddr.s_addr), ia_hash) 592 if ((BRIDGE_TEST || (ia->ia_ifp == ifp)) && 593 isaddr.s_addr == ia->ia_addr.sin_addr.s_addr) 594 goto match; 595 /* 596 * No match, use the first address on the receive interface 597 * as a dummy address for the rest of the function. 598 */ 599 ifa = TAILQ_FIRST(&ifp->if_addrhead); 600 if (ifa == NULL) { 601 m_freem(m); 602 return; 603 } 604 ia = ifatoia(ifa); 605match: 606 myaddr = ia->ia_addr.sin_addr; 607 if (!bcmp(ar_sha(ah), IF_LLADDR(ifp), ifp->if_addrlen)) { 608 m_freem(m); /* it's from me, ignore it. */ 609 return; 610 } 611 if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) { 612 log(LOG_ERR, 613 "arp: link address is broadcast for IP address %s!\n", 614 inet_ntoa(isaddr)); 615 m_freem(m); 616 return; 617 } 618 if (isaddr.s_addr == myaddr.s_addr) { 619 log(LOG_ERR, 620 "arp: %*D is using my IP address %s!\n", 621 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 622 inet_ntoa(isaddr)); 623 itaddr = myaddr; 624 goto reply; 625 } 626 la = arplookup(isaddr.s_addr, itaddr.s_addr == myaddr.s_addr, 0); 627 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { 628 /* the following is not an error when doing bridging */ 629 if (!BRIDGE_TEST && rt->rt_ifp != ifp) { 630 if (log_arp_wrong_iface) 631 log(LOG_ERR, "arp: %s is on %s%d but got reply from %*D on %s%d\n", 632 inet_ntoa(isaddr), 633 rt->rt_ifp->if_name, rt->rt_ifp->if_unit, 634 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 635 ifp->if_name, ifp->if_unit); 636 goto reply; 637 } 638 if (sdl->sdl_alen && 639 bcmp(ar_sha(ah), LLADDR(sdl), sdl->sdl_alen)) { 640 if (rt->rt_expire) { 641 if (log_arp_movements) 642 log(LOG_INFO, "arp: %s moved from %*D to %*D on %s%d\n", 643 inet_ntoa(isaddr), 644 ifp->if_addrlen, (u_char *)LLADDR(sdl), ":", 645 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 646 ifp->if_name, ifp->if_unit); 647 } else { 648 log(LOG_ERR, 649 "arp: %*D attempts to modify permanent entry for %s on %s%d\n", 650 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 651 inet_ntoa(isaddr), ifp->if_name, ifp->if_unit); 652 goto reply; 653 } 654 } 655 /* 656 * sanity check for the address length. 657 * XXX this does not work for protocols with variable address 658 * length. -is 659 */ 660 if (sdl->sdl_alen && 661 sdl->sdl_alen != ah->ar_hln) { 662 log(LOG_WARNING, 663 "arp from %*D: new addr len %d, was %d", 664 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 665 ah->ar_hln, sdl->sdl_alen); 666 } 667 if (ifp->if_addrlen != ah->ar_hln) { 668 log(LOG_WARNING, 669 "arp from %*D: addr len: new %d, i/f %d (ignored)", 670 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 671 ah->ar_hln, ifp->if_addrlen); 672 goto reply; 673 } 674 (void)memcpy(LLADDR(sdl), ar_sha(ah), 675 sdl->sdl_alen = ah->ar_hln); 676 sdl->sdl_rcf = (u_short)0; 677 /* 678 * If we receive an arp from a token-ring station over 679 * a token-ring nic then try to save the source 680 * routing info. 681 */ 682 if (ifp->if_type == IFT_ISO88025) { 683 th = (struct iso88025_header *)m->m_pkthdr.header; 684 rif_len = TR_RCF_RIFLEN(th->rcf); 685 if ((th->iso88025_shost[0] & TR_RII) && 686 (rif_len > 2)) { 687 sdl->sdl_rcf = th->rcf; 688 sdl->sdl_rcf ^= htons(TR_RCF_DIR); 689 memcpy(sdl->sdl_route, th->rd, rif_len - 2); 690 sdl->sdl_rcf &= ~htons(TR_RCF_BCST_MASK); 691 /* 692 * Set up source routing information for 693 * reply packet (XXX) 694 */ 695 m->m_data -= rif_len; 696 m->m_len += rif_len; 697 m->m_pkthdr.len += rif_len; 698 } else { 699 th->iso88025_shost[0] &= ~TR_RII; 700 } 701 m->m_data -= 8; 702 m->m_len += 8; 703 m->m_pkthdr.len += 8; 704 th->rcf = sdl->sdl_rcf; 705 } else { 706 sdl->sdl_rcf = (u_short)0; 707 } 708 if (rt->rt_expire) 709 rt->rt_expire = time_second + arpt_keep; 710 rt->rt_flags &= ~RTF_REJECT; 711 la->la_asked = 0; 712 if (la->la_hold) { 713 (*ifp->if_output)(ifp, la->la_hold, 714 rt_key(rt), rt); 715 la->la_hold = 0; 716 } 717 } 718reply: 719 if (op != ARPOP_REQUEST) { 720 m_freem(m); 721 return; 722 } 723 if (itaddr.s_addr == myaddr.s_addr) { 724 /* I am the target */ 725 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 726 (void)memcpy(ar_sha(ah), IF_LLADDR(ifp), ah->ar_hln); 727 } else { 728 la = arplookup(itaddr.s_addr, 0, SIN_PROXY); 729 if (la == NULL) { 730 struct sockaddr_in sin; 731 732 if (!arp_proxyall) { 733 m_freem(m); 734 return; 735 } 736 737 bzero(&sin, sizeof sin); 738 sin.sin_family = AF_INET; 739 sin.sin_len = sizeof sin; 740 sin.sin_addr = itaddr; 741 742 rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL); 743 if (!rt) { 744 m_freem(m); 745 return; 746 } 747 /* 748 * Don't send proxies for nodes on the same interface 749 * as this one came out of, or we'll get into a fight 750 * over who claims what Ether address. 751 */ 752 if (rt->rt_ifp == ifp) { 753 rtfree(rt); 754 m_freem(m); 755 return; 756 } 757 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 758 (void)memcpy(ar_sha(ah), IF_LLADDR(ifp), ah->ar_hln); 759 rtfree(rt); 760 761 /* 762 * Also check that the node which sent the ARP packet 763 * is on the the interface we expect it to be on. This 764 * avoids ARP chaos if an interface is connected to the 765 * wrong network. 766 */ 767 sin.sin_addr = isaddr; 768 769 rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL); 770 if (!rt) { 771 m_freem(m); 772 return; 773 } 774 if (rt->rt_ifp != ifp) { 775 log(LOG_INFO, "arp_proxy: ignoring request" 776 " from %s via %s%d, expecting %s%d\n", 777 inet_ntoa(isaddr), ifp->if_name, 778 ifp->if_unit, rt->rt_ifp->if_name, 779 rt->rt_ifp->if_unit); 780 rtfree(rt); 781 m_freem(m); 782 return; 783 } 784 rtfree(rt); 785 786#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 */ 850static void 851arptfree(la) 852 register struct llinfo_arp *la; 853{ 854 register struct rtentry *rt = la->la_rt; 855 register 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_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 */ 871static struct llinfo_arp * 872arplookup(addr, create, proxy) 873 u_long addr; 874 int create, proxy; 875{ 876 register 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 904void 905arp_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 916static void 917arp_init(void) 918{ 919 920 arpintrq.ifq_maxlen = 50; 921 mtx_init(&arpintrq.ifq_mtx, "arp_inq", MTX_DEF); 922} 923 924SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0); 925