Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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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 * $FreeBSD$ 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 77 SYSCTL_DECL(_net_link_ether); 78 SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, ""); 79 80 /* timer values */ 81 static int arpt_prune = (5*60*1); /* walk list every 5 minutes */ 82 static int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */ 83 static int arpt_down = 20; /* once declared down, don't send for 20 sec */ 84 85 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, prune_intvl, CTLFLAG_RW, 86 &arpt_prune, 0, ""); 87 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW, 88 &arpt_keep, 0, ""); 89 SYSCTL_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 94 struct 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 u_short la_preempt; /* #times we QUERIED before entry expiration */ 99 u_short la_asked; /* #times we QUERIED following expiration */ 100 #define la_timer la_rt->rt_rmx.rmx_expire /* deletion time in seconds */ 101 }; 102 103 static LIST_HEAD(, llinfo_arp) llinfo_arp; 104 105 struct ifqueue arpintrq = {0, 0, 0, 50}; 106 static int arp_inuse, arp_allocated, arpinit_done; 107 108 static int arp_maxtries = 5; 109 static int useloopback = 1; /* use loopback interface for local traffic */ 110 static int arp_proxyall = 0; 111 112 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW, 113 &arp_maxtries, 0, ""); 114 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW, 115 &useloopback, 0, ""); 116 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW, 117 &arp_proxyall, 0, ""); 118 119 static void arp_rtrequest __P((int, struct rtentry *, struct rt_addrinfo *)); 120 static void arprequest __P((struct ifnet *, 121 struct in_addr *, struct in_addr *, u_char *)); 122 static void arpintr __P((void)); 123 static void arptfree __P((struct llinfo_arp *)); 124 static void arptimer __P((void *)); 125 static struct llinfo_arp 126 *arplookup __P((u_long, int, int)); 127 #ifdef INET 128 static void in_arpinput __P((struct mbuf *)); 129 #endif 130 131 u_char arcbroadcastaddr = 0; 132 133 #define IF_BCASTADDR(ifp) \ 134 ((ifp)->if_type == IFT_ARCNET ? \ 135 &arcbroadcastaddr : etherbroadcastaddr) 136 137 /* 138 * Timeout routine. Age arp_tab entries periodically. 139 */ 140 /* ARGSUSED */ 141 static void 142 arptimer(ignored_arg) 143 void *ignored_arg; 144 { 145 int s = splnet(); 146 register struct llinfo_arp *la = LIST_FIRST(&llinfo_arp); 147 struct llinfo_arp *ola; 148 149 timeout(arptimer, (caddr_t)0, arpt_prune * hz); 150 while ((ola = la) != 0) { 151 register struct rtentry *rt = la->la_rt; 152 la = LIST_NEXT(la, la_le); 153 if (rt->rt_expire && rt->rt_expire <= time_second) 154 arptfree(ola); /* timer has expired, clear */ 155 } 156 splx(s); 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 rt_mask(rt) != NULL && 188 SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff) 189 rt->rt_flags |= RTF_CLONING; 190 if (rt->rt_flags & RTF_CLONING) { 191 /* 192 * Case 1: This route should come from a route to iface. 193 */ 194 rt_setgate(rt, rt_key(rt), 195 (struct sockaddr *)&null_sdl); 196 gate = rt->rt_gateway; 197 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 198 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 199 rt->rt_expire = time_second; 200 break; 201 } 202 /* Announce a new entry if requested. */ 203 if (rt->rt_flags & RTF_ANNOUNCE) 204 arprequest(rt->rt_ifp, 205 &SIN(rt_key(rt))->sin_addr, 206 &SIN(rt_key(rt))->sin_addr, 207 (u_char *)LLADDR(SDL(gate))); 208 /*FALLTHROUGH*/ 209 case RTM_RESOLVE: 210 if (gate->sa_family != AF_LINK || 211 gate->sa_len < sizeof(null_sdl)) { 212 log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n"); 213 break; 214 } 215 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 216 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 217 if (la != 0) 218 break; /* This happens on a route change */ 219 /* 220 * Case 2: This route may come from cloning, or a manual route 221 * add with a LL address. 222 */ 223 R_Malloc(la, struct llinfo_arp *, sizeof(*la)); 224 rt->rt_llinfo = (caddr_t)la; 225 if (la == 0) { 226 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); 227 break; 228 } 229 arp_inuse++, arp_allocated++; 230 Bzero(la, sizeof(*la)); 231 la->la_rt = rt; 232 rt->rt_flags |= RTF_LLINFO; 233 LIST_INSERT_HEAD(&llinfo_arp, la, la_le); 234 235 #ifdef INET 236 /* 237 * This keeps the multicast addresses from showing up 238 * in `arp -a' listings as unresolved. It's not actually 239 * functional. Then the same for broadcast. 240 */ 241 if (IN_MULTICAST(ntohl(SIN(rt_key(rt))->sin_addr.s_addr)) 242 && rt->rt_ifp->if_type != IFT_ARCNET) { 243 ETHER_MAP_IP_MULTICAST(&SIN(rt_key(rt))->sin_addr, 244 LLADDR(SDL(gate))); 245 SDL(gate)->sdl_alen = 6; 246 rt->rt_expire = 0; 247 } 248 if (in_broadcast(SIN(rt_key(rt))->sin_addr, rt->rt_ifp)) { 249 memcpy(LLADDR(SDL(gate)), IF_BCASTADDR(rt->rt_ifp), 250 rt->rt_ifp->if_addrlen); 251 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen; 252 rt->rt_expire = 0; 253 } 254 #endif 255 256 if (SIN(rt_key(rt))->sin_addr.s_addr == 257 (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) { 258 /* 259 * This test used to be 260 * if (loif.if_flags & IFF_UP) 261 * It allowed local traffic to be forced 262 * through the hardware by configuring the loopback down. 263 * However, it causes problems during network configuration 264 * for boards that can't receive packets they send. 265 * It is now necessary to clear "useloopback" and remove 266 * the route to force traffic out to the hardware. 267 */ 268 rt->rt_expire = 0; 269 Bcopy(IF_LLADDR(rt->rt_ifp), LLADDR(SDL(gate)), 270 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen); 271 if (useloopback) 272 rt->rt_ifp = loif; 273 274 } 275 break; 276 277 case RTM_DELETE: 278 if (la == 0) 279 break; 280 arp_inuse--; 281 LIST_REMOVE(la, la_le); 282 rt->rt_llinfo = 0; 283 rt->rt_flags &= ~RTF_LLINFO; 284 if (la->la_hold) 285 m_freem(la->la_hold); 286 Free((caddr_t)la); 287 } 288 } 289 290 /* 291 * Broadcast an ARP request. Caller specifies: 292 * - arp header source ip address 293 * - arp header target ip address 294 * - arp header source ethernet address 295 */ 296 static void 297 arprequest(ifp, sip, tip, enaddr) 298 register struct ifnet *ifp; 299 register struct in_addr *sip, *tip; 300 register u_char *enaddr; 301 { 302 register struct mbuf *m; 303 register struct ether_header *eh; 304 register struct arc_header *arh; 305 register struct arphdr *ah; 306 struct sockaddr sa; 307 static u_char llcx[] = { 0x82, 0x40, LLC_SNAP_LSAP, LLC_SNAP_LSAP, 308 LLC_UI, 0x00, 0x00, 0x00, 0x08, 0x06 }; 309 u_short ar_hrd; 310 311 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 312 return; 313 m->m_pkthdr.rcvif = (struct ifnet *)0; 314 switch (ifp->if_type) { 315 case IFT_ARCNET: 316 ar_hrd = htons(ARPHRD_ARCNET); 317 318 m->m_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 319 m->m_pkthdr.len = m->m_len; 320 MH_ALIGN(m, m->m_len); 321 322 arh = (struct arc_header *)sa.sa_data; 323 arh->arc_dhost = arcbroadcastaddr; 324 arh->arc_type = ARCTYPE_ARP; 325 326 ah = mtod(m, struct arphdr *); 327 break; 328 329 case IFT_ISO88025: 330 ar_hrd = htons(ARPHRD_IEEE802); 331 332 m->m_len = sizeof(llcx) + 333 arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 334 m->m_pkthdr.len = m->m_len; 335 MH_ALIGN(m, m->m_len); 336 337 (void)memcpy(mtod(m, caddr_t), llcx, sizeof(llcx)); 338 (void)memcpy(sa.sa_data, etherbroadcastaddr, 6); 339 (void)memcpy(sa.sa_data + 6, enaddr, 6); 340 sa.sa_data[6] |= TR_RII; 341 sa.sa_data[12] = TR_AC; 342 sa.sa_data[13] = TR_LLC_FRAME; 343 344 ah = (struct arphdr *)(mtod(m, char *) + sizeof(llcx)); 345 break; 346 case IFT_FDDI: 347 case IFT_ETHER: 348 /* 349 * This may not be correct for types not explicitly 350 * listed, but this is our best guess 351 */ 352 default: 353 ar_hrd = htons(ARPHRD_ETHER); 354 355 m->m_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 356 m->m_pkthdr.len = m->m_len; 357 MH_ALIGN(m, m->m_len); 358 359 eh = (struct ether_header *)sa.sa_data; 360 /* if_output will not swap */ 361 eh->ether_type = htons(ETHERTYPE_ARP); 362 (void)memcpy(eh->ether_dhost, etherbroadcastaddr, 363 sizeof(eh->ether_dhost)); 364 365 ah = mtod(m, struct arphdr *); 366 break; 367 } 368 369 ah->ar_hrd = ar_hrd; 370 ah->ar_pro = htons(ETHERTYPE_IP); 371 ah->ar_hln = ifp->if_addrlen; /* hardware address length */ 372 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 373 ah->ar_op = htons(ARPOP_REQUEST); 374 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln); 375 memset(ar_tha(ah), 0, ah->ar_hln); 376 (void)memcpy(ar_spa(ah), sip, ah->ar_pln); 377 (void)memcpy(ar_tpa(ah), tip, ah->ar_pln); 378 379 sa.sa_family = AF_UNSPEC; 380 sa.sa_len = sizeof(sa); 381 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 382 } 383 384 /* 385 * Resolve an IP address into an ethernet address. If success, 386 * desten is filled in. If there is no entry in arptab, 387 * set one up and broadcast a request for the IP address. 388 * Hold onto this mbuf and resend it once the address 389 * is finally resolved. A return value of 1 indicates 390 * that desten has been filled in and the packet should be sent 391 * normally; a 0 return indicates that the packet has been 392 * taken over here, either now or for later transmission. 393 */ 394 int 395 arpresolve(ifp, rt, m, dst, desten, rt0) 396 register struct ifnet *ifp; 397 register struct rtentry *rt; 398 struct mbuf *m; 399 register struct sockaddr *dst; 400 register u_char *desten; 401 struct rtentry *rt0; 402 { 403 struct llinfo_arp *la = 0; 404 struct sockaddr_dl *sdl; 405 406 if (m->m_flags & M_BCAST) { /* broadcast */ 407 (void)memcpy(desten, IF_BCASTADDR(ifp), ifp->if_addrlen); 408 return (1); 409 } 410 if (m->m_flags & M_MCAST && ifp->if_type != IFT_ARCNET) {/* multicast */ 411 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); 412 return(1); 413 } 414 if (rt) 415 la = (struct llinfo_arp *)rt->rt_llinfo; 416 if (la == 0) { 417 la = arplookup(SIN(dst)->sin_addr.s_addr, 1, 0); 418 if (la) 419 rt = la->la_rt; 420 } 421 if (la == 0 || rt == 0) { 422 log(LOG_DEBUG, "arpresolve: can't allocate llinfo for %s%s%s\n", 423 inet_ntoa(SIN(dst)->sin_addr), la ? "la" : "", 424 rt ? "rt" : ""); 425 m_freem(m); 426 return (0); 427 } 428 sdl = SDL(rt->rt_gateway); 429 /* 430 * Check the address family and length is valid, the address 431 * is resolved; otherwise, try to resolve. 432 */ 433 if ((rt->rt_expire == 0 || rt->rt_expire > time_second) && 434 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 435 /* 436 * If entry has an expiry time and it is approaching, 437 * see if we need to send an ARP request within this 438 * arpt_down interval. 439 */ 440 if ((rt->rt_expire != 0) && 441 (time_second + (arp_maxtries - la->la_preempt) * arpt_down 442 > rt->rt_expire)) { 443 arprequest(ifp, 444 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 445 &SIN(dst)->sin_addr, 446 IF_LLADDR(ifp)); 447 la->la_preempt++; 448 } 449 450 bcopy(LLADDR(sdl), desten, sdl->sdl_alen); 451 return 1; 452 } 453 /* 454 * If ARP is disabled on this interface, stop. 455 * XXX 456 * Probably should not allocate empty llinfo struct if we are 457 * not going to be sending out an arp request. 458 */ 459 if (ifp->if_flags & IFF_NOARP || ifp->if_ipending & IFF_STATICARP) { 460 m_freem(m); 461 return (0); 462 } 463 /* 464 * There is an arptab entry, but no ethernet address 465 * response yet. Replace the held mbuf with this 466 * latest one. 467 */ 468 if (la->la_hold) 469 m_freem(la->la_hold); 470 la->la_hold = m; 471 if (rt->rt_expire) { 472 rt->rt_flags &= ~RTF_REJECT; 473 if (la->la_asked == 0 || rt->rt_expire != time_second) { 474 rt->rt_expire = time_second; 475 if (la->la_asked++ < arp_maxtries) { 476 arprequest(ifp, 477 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 478 &SIN(dst)->sin_addr, 479 IF_LLADDR(ifp)); 480 } else { 481 rt->rt_flags |= RTF_REJECT; 482 rt->rt_expire += arpt_down; 483 la->la_preempt = la->la_asked = 0; 484 } 485 486 } 487 } 488 return (0); 489 } 490 491 /* 492 * Common length and type checks are done here, 493 * then the protocol-specific routine is called. 494 */ 495 static void 496 arpintr() 497 { 498 register struct mbuf *m; 499 register struct arphdr *ar; 500 int s; 501 502 while (arpintrq.ifq_head) { 503 s = splimp(); 504 IF_DEQUEUE(&arpintrq, m); 505 splx(s); 506 if (m == 0 || (m->m_flags & M_PKTHDR) == 0) 507 panic("arpintr"); 508 509 if (m->m_len < sizeof(struct arphdr) && 510 ((m = m_pullup(m, sizeof(struct arphdr))) == NULL)) { 511 log(LOG_ERR, "arp: runt packet -- m_pullup failed\n"); 512 continue; 513 } 514 ar = mtod(m, struct arphdr *); 515 516 if (ntohs(ar->ar_hrd) != ARPHRD_ETHER 517 && ntohs(ar->ar_hrd) != ARPHRD_IEEE802 518 && ntohs(ar->ar_hrd) != ARPHRD_ARCNET) { 519 log(LOG_ERR, 520 "arp: unknown hardware address format (0x%2D)\n", 521 (unsigned char *)&ar->ar_hrd, ""); 522 m_freem(m); 523 continue; 524 } 525 526 if (m->m_pkthdr.len < arphdr_len(ar) && 527 (m = m_pullup(m, arphdr_len(ar))) == NULL) { 528 log(LOG_ERR, "arp: runt packet\n"); 529 m_freem(m); 530 continue; 531 } 532 533 switch (ntohs(ar->ar_pro)) { 534 #ifdef INET 535 case ETHERTYPE_IP: 536 in_arpinput(m); 537 continue; 538 #endif 539 } 540 m_freem(m); 541 } 542 } 543 544 #ifdef INET 545 /* 546 * ARP for Internet protocols on 10 Mb/s Ethernet. 547 * Algorithm is that given in RFC 826. 548 * In addition, a sanity check is performed on the sender 549 * protocol address, to catch impersonators. 550 * We no longer handle negotiations for use of trailer protocol: 551 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 552 * along with IP replies if we wanted trailers sent to us, 553 * and also sent them in response to IP replies. 554 * This allowed either end to announce the desire to receive 555 * trailer packets. 556 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 557 * but formerly didn't normally send requests. 558 */ 559 static int log_arp_wrong_iface = 1; 560 static int log_arp_movements = 1; 561 562 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW, 563 &log_arp_wrong_iface, 0, 564 "log arp packets arriving on the wrong interface"); 565 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_movements, CTLFLAG_RW, 566 &log_arp_movements, 0, 567 "log arp replies from MACs different than the one in the cache"); 568 569 570 static void 571 in_arpinput(m) 572 struct mbuf *m; 573 { 574 register struct arphdr *ah; 575 register struct ifnet *ifp = m->m_pkthdr.rcvif; 576 struct ether_header *eh; 577 struct arc_header *arh; 578 struct iso88025_header *th = (struct iso88025_header *)0; 579 struct iso88025_sockaddr_dl_data *trld; 580 register struct llinfo_arp *la = 0; 581 register struct rtentry *rt; 582 struct ifaddr *ifa; 583 struct in_ifaddr *ia; 584 struct sockaddr_dl *sdl; 585 struct sockaddr sa; 586 struct in_addr isaddr, itaddr, myaddr; 587 int op, rif_len; 588 int req_len; 589 590 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 591 if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) { 592 log(LOG_ERR, "in_arp: runt packet -- m_pullup failed\n"); 593 return; 594 } 595 596 ah = mtod(m, struct arphdr *); 597 op = ntohs(ah->ar_op); 598 (void)memcpy(&isaddr, ar_spa(ah), sizeof (isaddr)); 599 (void)memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr)); 600 #ifdef BRIDGE 601 #define BRIDGE_TEST (do_bridge) 602 #else 603 #define BRIDGE_TEST (0) /* cc will optimise the test away */ 604 #endif 605 /* 606 * For a bridge, we want to check the address irrespective 607 * of the receive interface. (This will change slightly 608 * when we have clusters of interfaces). 609 */ 610 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) 611 if ((BRIDGE_TEST || (ia->ia_ifp == ifp)) && 612 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) 613 goto match; 614 LIST_FOREACH(ia, INADDR_HASH(isaddr.s_addr), ia_hash) 615 if ((BRIDGE_TEST || (ia->ia_ifp == ifp)) && 616 isaddr.s_addr == ia->ia_addr.sin_addr.s_addr) 617 goto match; 618 /* 619 * No match, use the first inet address on the receive interface 620 * as a dummy address for the rest of the function. 621 */ 622 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) 623 if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_INET) { 624 ia = ifatoia(ifa); 625 goto match; 626 } 627 /* 628 * If bridging, fall back to using any inet address. 629 * This is probably incorrect, the right way being try to match 630 * addresses for interfaces in the same cluster, so if we 631 * get here we should always drop the packet. 632 */ 633 if (!BRIDGE_TEST || 634 (ia = TAILQ_FIRST(&in_ifaddrhead)) == NULL) { 635 m_freem(m); 636 return; 637 } 638 match: 639 myaddr = ia->ia_addr.sin_addr; 640 if (!bcmp(ar_sha(ah), IF_LLADDR(ifp), ifp->if_addrlen)) { 641 m_freem(m); /* it's from me, ignore it. */ 642 return; 643 } 644 if (!bcmp(ar_sha(ah), IF_BCASTADDR(ifp), ifp->if_addrlen)) { 645 log(LOG_ERR, 646 "arp: link address is broadcast for IP address %s!\n", 647 inet_ntoa(isaddr)); 648 m_freem(m); 649 return; 650 } 651 if (isaddr.s_addr == myaddr.s_addr) { 652 log(LOG_ERR, 653 "arp: %*D is using my IP address %s!\n", 654 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 655 inet_ntoa(isaddr)); 656 itaddr = myaddr; 657 goto reply; 658 } 659 if (ifp->if_ipending & IFF_STATICARP) 660 goto reply; 661 la = arplookup(isaddr.s_addr, itaddr.s_addr == myaddr.s_addr, 0); 662 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { 663 /* the following is not an error when doing bridging */ 664 if (!BRIDGE_TEST && rt->rt_ifp != ifp) { 665 if (log_arp_wrong_iface) 666 log(LOG_ERR, "arp: %s is on %s%d but got reply from %*D on %s%d\n", 667 inet_ntoa(isaddr), 668 rt->rt_ifp->if_name, rt->rt_ifp->if_unit, 669 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 670 ifp->if_name, ifp->if_unit); 671 goto reply; 672 } 673 if (sdl->sdl_alen && 674 bcmp(ar_sha(ah), LLADDR(sdl), sdl->sdl_alen)) { 675 if (rt->rt_expire) { 676 if (log_arp_movements) 677 log(LOG_INFO, "arp: %s moved from %*D to %*D on %s%d\n", 678 inet_ntoa(isaddr), 679 ifp->if_addrlen, (u_char *)LLADDR(sdl), ":", 680 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 681 ifp->if_name, ifp->if_unit); 682 } else { 683 log(LOG_ERR, 684 "arp: %*D attempts to modify permanent entry for %s on %s%d\n", 685 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 686 inet_ntoa(isaddr), ifp->if_name, ifp->if_unit); 687 goto reply; 688 } 689 } 690 /* 691 * sanity check for the address length. 692 * XXX this does not work for protocols with variable address 693 * length. -is 694 */ 695 if (sdl->sdl_alen && 696 sdl->sdl_alen != ah->ar_hln) { 697 log(LOG_WARNING, 698 "arp from %*D: new addr len %d, was %d", 699 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 700 ah->ar_hln, sdl->sdl_alen); 701 } 702 if (ifp->if_addrlen != ah->ar_hln) { 703 log(LOG_WARNING, 704 "arp from %*D: addr len: new %d, i/f %d (ignored)", 705 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 706 ah->ar_hln, ifp->if_addrlen); 707 goto reply; 708 } 709 (void)memcpy(LLADDR(sdl), ar_sha(ah), 710 sdl->sdl_alen = ah->ar_hln); 711 /* 712 * If we receive an arp from a token-ring station over 713 * a token-ring nic then try to save the source 714 * routing info. 715 */ 716 if (ifp->if_type == IFT_ISO88025) { 717 th = (struct iso88025_header *)m->m_pkthdr.header; 718 trld = SDL_ISO88025(sdl); 719 rif_len = TR_RCF_RIFLEN(th->rcf); 720 if ((th->iso88025_shost[0] & TR_RII) && 721 (rif_len > 2)) { 722 trld->trld_rcf = th->rcf; 723 trld->trld_rcf ^= htons(TR_RCF_DIR); 724 memcpy(trld->trld_route, th->rd, rif_len - 2); 725 trld->trld_rcf &= ~htons(TR_RCF_BCST_MASK); 726 /* 727 * Set up source routing information for 728 * reply packet (XXX) 729 */ 730 m->m_data -= rif_len; 731 m->m_len += rif_len; 732 m->m_pkthdr.len += rif_len; 733 } else { 734 th->iso88025_shost[0] &= ~TR_RII; 735 trld->trld_rcf = 0; 736 } 737 m->m_data -= 8; 738 m->m_len += 8; 739 m->m_pkthdr.len += 8; 740 th->rcf = trld->trld_rcf; 741 } 742 if (rt->rt_expire) 743 rt->rt_expire = time_second + arpt_keep; 744 rt->rt_flags &= ~RTF_REJECT; 745 la->la_preempt = la->la_asked = 0; 746 if (la->la_hold) { 747 (*ifp->if_output)(ifp, la->la_hold, 748 rt_key(rt), rt); 749 la->la_hold = 0; 750 } 751 } 752 reply: 753 if (op != ARPOP_REQUEST) { 754 m_freem(m); 755 return; 756 } 757 if (itaddr.s_addr == myaddr.s_addr) { 758 /* I am the target */ 759 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 760 (void)memcpy(ar_sha(ah), IF_LLADDR(ifp), ah->ar_hln); 761 } else { 762 la = arplookup(itaddr.s_addr, 0, SIN_PROXY); 763 if (la == NULL) { 764 struct sockaddr_in sin; 765 766 if (!arp_proxyall) { 767 m_freem(m); 768 return; 769 } 770 771 bzero(&sin, sizeof sin); 772 sin.sin_family = AF_INET; 773 sin.sin_len = sizeof sin; 774 sin.sin_addr = itaddr; 775 776 rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL); 777 if (!rt) { 778 m_freem(m); 779 return; 780 } 781 /* 782 * Don't send proxies for nodes on the same interface 783 * as this one came out of, or we'll get into a fight 784 * over who claims what Ether address. 785 */ 786 if (rt->rt_ifp == ifp) { 787 rtfree(rt); 788 m_freem(m); 789 return; 790 } 791 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 792 (void)memcpy(ar_sha(ah), IF_LLADDR(ifp), ah->ar_hln); 793 rtfree(rt); 794 #ifdef DEBUG_PROXY 795 printf("arp: proxying for %s\n", 796 inet_ntoa(itaddr)); 797 #endif 798 } else { 799 rt = la->la_rt; 800 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 801 sdl = SDL(rt->rt_gateway); 802 (void)memcpy(ar_sha(ah), LLADDR(sdl), ah->ar_hln); 803 } 804 } 805 806 (void)memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln); 807 (void)memcpy(ar_spa(ah), &itaddr, ah->ar_pln); 808 ah->ar_op = htons(ARPOP_REPLY); 809 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 810 switch (ifp->if_type) { 811 case IFT_ARCNET: 812 arh = (struct arc_header *)sa.sa_data; 813 arh->arc_dhost = *ar_tha(ah); 814 arh->arc_type = ARCTYPE_ARP; 815 break; 816 817 case IFT_ISO88025: 818 /* Re-arrange the source/dest address */ 819 memcpy(th->iso88025_dhost, th->iso88025_shost, 820 sizeof(th->iso88025_dhost)); 821 memcpy(th->iso88025_shost, IF_LLADDR(ifp), 822 sizeof(th->iso88025_shost)); 823 /* Set the source routing bit if neccesary */ 824 if (th->iso88025_dhost[0] & TR_RII) { 825 th->iso88025_dhost[0] &= ~TR_RII; 826 if (TR_RCF_RIFLEN(th->rcf) > 2) 827 th->iso88025_shost[0] |= TR_RII; 828 } 829 /* Copy the addresses, ac and fc into sa_data */ 830 memcpy(sa.sa_data, th->iso88025_dhost, 831 sizeof(th->iso88025_dhost) * 2); 832 sa.sa_data[(sizeof(th->iso88025_dhost) * 2)] = TR_AC; 833 sa.sa_data[(sizeof(th->iso88025_dhost) * 2) + 1] = TR_LLC_FRAME; 834 break; 835 case IFT_ETHER: 836 case IFT_FDDI: 837 /* 838 * May not be correct for types not explictly 839 * listed, but it is our best guess. 840 */ 841 default: 842 eh = (struct ether_header *)sa.sa_data; 843 (void)memcpy(eh->ether_dhost, ar_tha(ah), 844 sizeof(eh->ether_dhost)); 845 eh->ether_type = htons(ETHERTYPE_ARP); 846 break; 847 } 848 sa.sa_family = AF_UNSPEC; 849 sa.sa_len = sizeof(sa); 850 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 851 return; 852 } 853 #endif 854 855 /* 856 * Free an arp entry. 857 */ 858 static void 859 arptfree(la) 860 register struct llinfo_arp *la; 861 { 862 register struct rtentry *rt = la->la_rt; 863 register struct sockaddr_dl *sdl; 864 if (rt == 0) 865 panic("arptfree"); 866 if (rt->rt_refcnt > 0 && (sdl = SDL(rt->rt_gateway)) && 867 sdl->sdl_family == AF_LINK) { 868 sdl->sdl_alen = 0; 869 la->la_preempt = la->la_asked = 0; 870 rt->rt_flags &= ~RTF_REJECT; 871 return; 872 } 873 rtrequest(RTM_DELETE, rt_key(rt), (struct sockaddr *)0, rt_mask(rt), 874 0, (struct rtentry **)0); 875 } 876 /* 877 * Lookup or enter a new address in arptab. 878 */ 879 static struct llinfo_arp * 880 arplookup(addr, create, proxy) 881 u_long addr; 882 int create, proxy; 883 { 884 register struct rtentry *rt; 885 static struct sockaddr_inarp sin = {sizeof(sin), AF_INET }; 886 const char *why = 0; 887 888 sin.sin_addr.s_addr = addr; 889 sin.sin_other = proxy ? SIN_PROXY : 0; 890 rt = rtalloc1((struct sockaddr *)&sin, create, 0UL); 891 if (rt == 0) 892 return (0); 893 rt->rt_refcnt--; 894 895 if (rt->rt_flags & RTF_GATEWAY) 896 why = "host is not on local network"; 897 else if ((rt->rt_flags & RTF_LLINFO) == 0) 898 why = "could not allocate llinfo"; 899 else if (rt->rt_gateway->sa_family != AF_LINK) 900 why = "gateway route is not ours"; 901 902 if (why) { 903 if (create) 904 log(LOG_DEBUG, "arplookup %s failed: %s\n", 905 inet_ntoa(sin.sin_addr), why); 906 907 /* If there are no references to this route, purge it */ 908 if (rt->rt_refcnt <= 0 && 909 (rt->rt_flags & RTF_WASCLONED) == RTF_WASCLONED) { 910 rtrequest(RTM_DELETE, 911 (struct sockaddr *)rt_key(rt), 912 rt->rt_gateway, rt_mask(rt), 913 rt->rt_flags, 0); 914 } 915 return (0); 916 } 917 return ((struct llinfo_arp *)rt->rt_llinfo); 918 } 919 920 void 921 arp_ifinit(ifp, ifa) 922 struct ifnet *ifp; 923 struct ifaddr *ifa; 924 { 925 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY) 926 arprequest(ifp, &IA_SIN(ifa)->sin_addr, 927 &IA_SIN(ifa)->sin_addr, IF_LLADDR(ifp)); 928 ifa->ifa_rtrequest = arp_rtrequest; 929 ifa->ifa_flags |= RTF_CLONING; 930 } 931 932 static void 933 arp_init(void) 934 { 935 LIST_INIT(&llinfo_arp); 936 register_netisr(NETISR_ARP, arpintr); 937 } 938 939 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0);
Cache object: 4b5d2cab94f4a3a10c0c68ea3cc71c32
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