1 /* $OpenBSD: if_ether.c,v 1.54 2004/06/21 23:50:37 tholo Exp $ */ 2 /* $NetBSD: if_ether.c,v 1.31 1996/05/11 12:59:58 mycroft Exp $ */ 3 4 /* 5 * Copyright (c) 1982, 1986, 1988, 1993 6 * The Regents of the University of California. All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 * @(#)if_ether.c 8.1 (Berkeley) 6/10/93 33 */ 34 35 /* 36 * Ethernet address resolution protocol. 37 * TODO: 38 * add "inuse/lock" bit (or ref. count) along with valid bit 39 */ 40 41 #ifdef INET 42 #include "carp.h" 43 44 #include "bridge.h" 45 46 #include <sys/param.h> 47 #include <sys/systm.h> 48 #include <sys/mbuf.h> 49 #include <sys/socket.h> 50 #include <sys/kernel.h> 51 #include <sys/syslog.h> 52 #include <sys/proc.h> 53 54 #include <net/if.h> 55 #include <net/if_dl.h> 56 #include <net/route.h> 57 #include <net/if_fddi.h> 58 #include <net/if_types.h> 59 60 #include <netinet/in.h> 61 #include <netinet/in_var.h> 62 #include <netinet/if_ether.h> 63 #if NCARP > 0 64 #include <netinet/ip_carp.h> 65 #endif 66 67 #define SIN(s) ((struct sockaddr_in *)s) 68 #define SDL(s) ((struct sockaddr_dl *)s) 69 #define SRP(s) ((struct sockaddr_inarp *)s) 70 71 /* 72 * ARP trailer negotiation. Trailer protocol is not IP specific, 73 * but ARP request/response use IP addresses. 74 */ 75 #define ETHERTYPE_IPTRAILERS ETHERTYPE_TRAIL 76 77 /* timer values */ 78 int arpt_prune = (5*60*1); /* walk list every 5 minutes */ 79 int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */ 80 int arpt_down = 20; /* once declared down, don't send for 20 secs */ 81 #define rt_expire rt_rmx.rmx_expire 82 83 void arptfree(struct llinfo_arp *); 84 void arptimer(void *); 85 struct llinfo_arp *arplookup(u_int32_t, int, int); 86 void in_arpinput(struct mbuf *); 87 88 LIST_HEAD(, llinfo_arp) llinfo_arp; 89 struct ifqueue arpintrq = {0, 0, 0, 50}; 90 int arp_inuse, arp_allocated, arp_intimer; 91 int arp_maxtries = 5; 92 int useloopback = 1; /* use loopback interface for local traffic */ 93 int arpinit_done = 0; 94 95 /* revarp state */ 96 struct in_addr myip, srv_ip; 97 int myip_initialized = 0; 98 int revarp_in_progress = 0; 99 struct ifnet *myip_ifp = NULL; 100 101 #ifdef DDB 102 #include <uvm/uvm_extern.h> 103 104 void db_print_sa(struct sockaddr *); 105 void db_print_ifa(struct ifaddr *); 106 void db_print_llinfo(caddr_t); 107 int db_show_radix_node(struct radix_node *, void *); 108 #endif 109 110 /* 111 * Timeout routine. Age arp_tab entries periodically. 112 */ 113 /* ARGSUSED */ 114 void 115 arptimer(arg) 116 void *arg; 117 { 118 struct timeout *to = (struct timeout *)arg; 119 int s; 120 struct llinfo_arp *la, *nla; 121 122 s = splsoftnet(); 123 timeout_add(to, arpt_prune * hz); 124 for (la = LIST_FIRST(&llinfo_arp); la != LIST_END(&llinfo_arp); 125 la = nla) { 126 struct rtentry *rt = la->la_rt; 127 128 nla = LIST_NEXT(la, la_list); 129 if (rt->rt_expire && rt->rt_expire <= time_second) 130 arptfree(la); /* timer has expired; clear */ 131 } 132 splx(s); 133 } 134 135 /* 136 * Parallel to llc_rtrequest. 137 */ 138 void 139 arp_rtrequest(req, rt, info) 140 int req; 141 struct rtentry *rt; 142 struct rt_addrinfo *info; 143 { 144 struct sockaddr *gate = rt->rt_gateway; 145 struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo; 146 static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK}; 147 struct in_ifaddr *ia; 148 struct ifaddr *ifa; 149 150 if (!arpinit_done) { 151 static struct timeout arptimer_to; 152 153 arpinit_done = 1; 154 /* 155 * We generate expiration times from time.tv_sec 156 * so avoid accidently creating permanent routes. 157 */ 158 if (time_second == 0) { 159 time_second++; 160 } 161 162 timeout_set(&arptimer_to, arptimer, &arptimer_to); 163 timeout_add(&arptimer_to, hz); 164 } 165 166 if (rt->rt_flags & RTF_GATEWAY) { 167 if (req != RTM_ADD) 168 return; 169 170 /* 171 * linklayers with particular link MTU limitation. it is a bit 172 * awkward to have FDDI handling here, we should split ARP from 173 * netinet/if_ether.c like NetBSD does. 174 */ 175 switch (rt->rt_ifp->if_type) { 176 case IFT_FDDI: 177 if (rt->rt_ifp->if_mtu > FDDIIPMTU) 178 rt->rt_rmx.rmx_mtu = FDDIIPMTU; 179 break; 180 } 181 182 return; 183 } 184 185 switch (req) { 186 187 case RTM_ADD: 188 /* 189 * XXX: If this is a manually added route to interface 190 * such as older version of routed or gated might provide, 191 * restore cloning bit. 192 */ 193 if ((rt->rt_flags & RTF_HOST) == 0 && 194 SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff) 195 rt->rt_flags |= RTF_CLONING; 196 if (rt->rt_flags & RTF_CLONING) { 197 /* 198 * Case 1: This route should come from a route to iface. 199 */ 200 rt_setgate(rt, rt_key(rt), 201 (struct sockaddr *)&null_sdl); 202 gate = rt->rt_gateway; 203 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 204 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 205 /* 206 * Give this route an expiration time, even though 207 * it's a "permanent" route, so that routes cloned 208 * from it do not need their expiration time set. 209 */ 210 rt->rt_expire = time_second; 211 /* 212 * linklayers with particular link MTU limitation. 213 */ 214 switch (rt->rt_ifp->if_type) { 215 case IFT_FDDI: 216 if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0 && 217 (rt->rt_rmx.rmx_mtu > FDDIIPMTU || 218 (rt->rt_rmx.rmx_mtu == 0 && 219 rt->rt_ifp->if_mtu > FDDIIPMTU))) 220 rt->rt_rmx.rmx_mtu = FDDIIPMTU; 221 break; 222 } 223 break; 224 } 225 /* Announce a new entry if requested. */ 226 if (rt->rt_flags & RTF_ANNOUNCE) 227 arprequest(rt->rt_ifp, 228 &SIN(rt_key(rt))->sin_addr.s_addr, 229 &SIN(rt_key(rt))->sin_addr.s_addr, 230 (u_char *)LLADDR(SDL(gate))); 231 /*FALLTHROUGH*/ 232 case RTM_RESOLVE: 233 if (gate->sa_family != AF_LINK || 234 gate->sa_len < sizeof(null_sdl)) { 235 log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n"); 236 break; 237 } 238 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 239 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 240 if (la != 0) 241 break; /* This happens on a route change */ 242 /* 243 * Case 2: This route may come from cloning, or a manual route 244 * add with a LL address. 245 */ 246 R_Malloc(la, struct llinfo_arp *, sizeof(*la)); 247 rt->rt_llinfo = (caddr_t)la; 248 if (la == 0) { 249 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); 250 break; 251 } 252 arp_inuse++, arp_allocated++; 253 Bzero(la, sizeof(*la)); 254 la->la_rt = rt; 255 rt->rt_flags |= RTF_LLINFO; 256 LIST_INSERT_HEAD(&llinfo_arp, la, la_list); 257 258 TAILQ_FOREACH(ia, &in_ifaddr, ia_list) { 259 if (ia->ia_ifp == rt->rt_ifp && 260 SIN(rt_key(rt))->sin_addr.s_addr == 261 (IA_SIN(ia))->sin_addr.s_addr) 262 break; 263 } 264 if (ia) { 265 /* 266 * This test used to be 267 * if (lo0ifp->if_flags & IFF_UP) 268 * It allowed local traffic to be forced through 269 * the hardware by configuring the loopback down. 270 * However, it causes problems during network 271 * configuration for boards that can't receive 272 * packets they send. It is now necessary to clear 273 * "useloopback" and remove the route to force 274 * traffic out to the hardware. 275 * 276 * In 4.4BSD, the above "if" statement checked 277 * rt->rt_ifa against rt_key(rt). It was changed 278 * to the current form so that we can provide a 279 * better support for multiple IPv4 addresses on a 280 * interface. 281 */ 282 rt->rt_expire = 0; 283 Bcopy(((struct arpcom *)rt->rt_ifp)->ac_enaddr, 284 LLADDR(SDL(gate)), 285 SDL(gate)->sdl_alen = ETHER_ADDR_LEN); 286 if (useloopback) 287 rt->rt_ifp = lo0ifp; 288 /* 289 * make sure to set rt->rt_ifa to the interface 290 * address we are using, otherwise we will have trouble 291 * with source address selection. 292 */ 293 ifa = &ia->ia_ifa; 294 if (ifa != rt->rt_ifa) { 295 IFAFREE(rt->rt_ifa); 296 ifa->ifa_refcnt++; 297 rt->rt_ifa = ifa; 298 } 299 } 300 break; 301 302 case RTM_DELETE: 303 if (la == 0) 304 break; 305 arp_inuse--; 306 LIST_REMOVE(la, la_list); 307 rt->rt_llinfo = 0; 308 rt->rt_flags &= ~RTF_LLINFO; 309 if (la->la_hold) 310 m_freem(la->la_hold); 311 Free((caddr_t)la); 312 } 313 } 314 315 /* 316 * Broadcast an ARP request. Caller specifies: 317 * - arp header source ip address 318 * - arp header target ip address 319 * - arp header source ethernet address 320 */ 321 void 322 arprequest(ifp, sip, tip, enaddr) 323 struct ifnet *ifp; 324 u_int32_t *sip, *tip; 325 u_int8_t *enaddr; 326 { 327 struct mbuf *m; 328 struct ether_header *eh; 329 struct ether_arp *ea; 330 struct sockaddr sa; 331 332 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 333 return; 334 m->m_len = sizeof(*ea); 335 m->m_pkthdr.len = sizeof(*ea); 336 MH_ALIGN(m, sizeof(*ea)); 337 ea = mtod(m, struct ether_arp *); 338 eh = (struct ether_header *)sa.sa_data; 339 bzero((caddr_t)ea, sizeof (*ea)); 340 bcopy((caddr_t)etherbroadcastaddr, (caddr_t)eh->ether_dhost, 341 sizeof(eh->ether_dhost)); 342 eh->ether_type = htons(ETHERTYPE_ARP); /* if_output will not swap */ 343 ea->arp_hrd = htons(ARPHRD_ETHER); 344 ea->arp_pro = htons(ETHERTYPE_IP); 345 ea->arp_hln = sizeof(ea->arp_sha); /* hardware address length */ 346 ea->arp_pln = sizeof(ea->arp_spa); /* protocol address length */ 347 ea->arp_op = htons(ARPOP_REQUEST); 348 bcopy((caddr_t)enaddr, (caddr_t)eh->ether_shost, 349 sizeof(eh->ether_shost)); 350 bcopy((caddr_t)enaddr, (caddr_t)ea->arp_sha, sizeof(ea->arp_sha)); 351 bcopy((caddr_t)sip, (caddr_t)ea->arp_spa, sizeof(ea->arp_spa)); 352 bcopy((caddr_t)tip, (caddr_t)ea->arp_tpa, sizeof(ea->arp_tpa)); 353 sa.sa_family = AF_UNSPEC; 354 sa.sa_len = sizeof(sa); 355 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 356 } 357 358 /* 359 * Resolve an IP address into an ethernet address. If success, 360 * desten is filled in. If there is no entry in arptab, 361 * set one up and broadcast a request for the IP address. 362 * Hold onto this mbuf and resend it once the address 363 * is finally resolved. A return value of 1 indicates 364 * that desten has been filled in and the packet should be sent 365 * normally; a 0 return indicates that the packet has been 366 * taken over here, either now or for later transmission. 367 */ 368 int 369 arpresolve(ac, rt, m, dst, desten) 370 struct arpcom *ac; 371 struct rtentry *rt; 372 struct mbuf *m; 373 struct sockaddr *dst; 374 u_char *desten; 375 { 376 struct llinfo_arp *la; 377 struct sockaddr_dl *sdl; 378 379 if (m->m_flags & M_BCAST) { /* broadcast */ 380 bcopy((caddr_t)etherbroadcastaddr, (caddr_t)desten, 381 sizeof(etherbroadcastaddr)); 382 return (1); 383 } 384 if (m->m_flags & M_MCAST) { /* multicast */ 385 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); 386 return (1); 387 } 388 if (rt) 389 la = (struct llinfo_arp *)rt->rt_llinfo; 390 else { 391 if ((la = arplookup(SIN(dst)->sin_addr.s_addr, 1, 0)) != NULL) 392 rt = la->la_rt; 393 } 394 if (la == 0 || rt == 0) { 395 log(LOG_DEBUG, "arpresolve: can't allocate llinfo\n"); 396 m_freem(m); 397 return (0); 398 } 399 sdl = SDL(rt->rt_gateway); 400 /* 401 * Check the address family and length is valid, the address 402 * is resolved; otherwise, try to resolve. 403 */ 404 if ((rt->rt_expire == 0 || rt->rt_expire > time_second) && 405 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 406 bcopy(LLADDR(sdl), desten, sdl->sdl_alen); 407 return 1; 408 } 409 if (((struct ifnet *)ac)->if_flags & IFF_NOARP) 410 return 0; 411 412 /* 413 * There is an arptab entry, but no ethernet address 414 * response yet. Replace the held mbuf with this 415 * latest one. 416 */ 417 if (la->la_hold) 418 m_freem(la->la_hold); 419 la->la_hold = m; 420 /* 421 * Re-send the ARP request when appropriate. 422 */ 423 #ifdef DIAGNOSTIC 424 if (rt->rt_expire == 0) { 425 /* This should never happen. (Should it? -gwr) */ 426 printf("arpresolve: unresolved and rt_expire == 0\n"); 427 /* Set expiration time to now (expired). */ 428 rt->rt_expire = time_second; 429 } 430 #endif 431 if (rt->rt_expire) { 432 rt->rt_flags &= ~RTF_REJECT; 433 if (la->la_asked == 0 || rt->rt_expire != time_second) { 434 rt->rt_expire = time_second; 435 if (la->la_asked++ < arp_maxtries) 436 arprequest(&ac->ac_if, 437 &(SIN(rt->rt_ifa->ifa_addr)->sin_addr.s_addr), 438 &(SIN(dst)->sin_addr.s_addr), 439 ac->ac_enaddr); 440 else { 441 rt->rt_flags |= RTF_REJECT; 442 rt->rt_expire += arpt_down; 443 la->la_asked = 0; 444 } 445 } 446 } 447 return (0); 448 } 449 450 /* 451 * Common length and type checks are done here, 452 * then the protocol-specific routine is called. 453 */ 454 void 455 arpintr() 456 { 457 struct mbuf *m; 458 struct arphdr *ar; 459 int s, len; 460 461 while (arpintrq.ifq_head) { 462 s = splimp(); 463 IF_DEQUEUE(&arpintrq, m); 464 splx(s); 465 if (m == 0 || (m->m_flags & M_PKTHDR) == 0) 466 panic("arpintr"); 467 468 len = sizeof(struct arphdr); 469 if (m->m_len < len && (m = m_pullup(m, len)) == NULL) 470 continue; 471 472 ar = mtod(m, struct arphdr *); 473 if (ntohs(ar->ar_hrd) != ARPHRD_ETHER) { 474 m_freem(m); 475 continue; 476 } 477 478 len += 2 * (ar->ar_hln + ar->ar_pln); 479 if (m->m_len < len && (m = m_pullup(m, len)) == NULL) 480 continue; 481 482 switch (ntohs(ar->ar_pro)) { 483 case ETHERTYPE_IP: 484 case ETHERTYPE_IPTRAILERS: 485 in_arpinput(m); 486 continue; 487 } 488 m_freem(m); 489 } 490 } 491 492 /* 493 * ARP for Internet protocols on Ethernet. 494 * Algorithm is that given in RFC 826. 495 * In addition, a sanity check is performed on the sender 496 * protocol address, to catch impersonators. 497 * We no longer handle negotiations for use of trailer protocol: 498 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 499 * along with IP replies if we wanted trailers sent to us, 500 * and also sent them in response to IP replies. 501 * This allowed either end to announce the desire to receive 502 * trailer packets. 503 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 504 * but formerly didn't normally send requests. 505 */ 506 void 507 in_arpinput(m) 508 struct mbuf *m; 509 { 510 struct ether_arp *ea; 511 struct arpcom *ac = (struct arpcom *)m->m_pkthdr.rcvif; 512 struct ether_header *eh; 513 struct llinfo_arp *la = 0; 514 struct rtentry *rt; 515 struct in_ifaddr *ia; 516 #if NBRIDGE > 0 517 struct in_ifaddr *bridge_ia = NULL; 518 #endif 519 struct sockaddr_dl *sdl; 520 struct sockaddr sa; 521 struct in_addr isaddr, itaddr, myaddr; 522 u_int8_t *enaddr = NULL; 523 int op; 524 525 ea = mtod(m, struct ether_arp *); 526 op = ntohs(ea->arp_op); 527 if ((op != ARPOP_REQUEST) && (op != ARPOP_REPLY)) 528 goto out; 529 #if notyet 530 if ((op == ARPOP_REPLY) && (m->m_flags & (M_BCAST|M_MCAST))) { 531 log(LOG_ERR, 532 "arp: received reply to broadcast or multicast address\n"); 533 goto out; 534 } 535 #endif 536 537 bcopy((caddr_t)ea->arp_tpa, (caddr_t)&itaddr, sizeof(itaddr)); 538 bcopy((caddr_t)ea->arp_spa, (caddr_t)&isaddr, sizeof(isaddr)); 539 540 TAILQ_FOREACH(ia, &in_ifaddr, ia_list) { 541 if (itaddr.s_addr != ia->ia_addr.sin_addr.s_addr) 542 continue; 543 544 if (ia->ia_ifp == m->m_pkthdr.rcvif) 545 break; 546 #if NBRIDGE > 0 547 /* 548 * If the interface we received the packet on 549 * is part of a bridge, check to see if we need 550 * to "bridge" the packet to ourselves at this 551 * layer. Note we still prefer a perfect match, 552 * but allow this weaker match if necessary. 553 */ 554 if (m->m_pkthdr.rcvif->if_bridge != NULL && 555 m->m_pkthdr.rcvif->if_bridge == ia->ia_ifp->if_bridge) 556 bridge_ia = ia; 557 #endif 558 559 #if NCARP > 0 560 if (ac->ac_if.if_carp) { 561 if (carp_iamatch(ac->ac_if.if_carp, ia, 562 &isaddr, &enaddr)) 563 break; 564 } 565 #endif 566 } 567 568 #if NBRIDGE > 0 569 if (ia == NULL && bridge_ia != NULL) { 570 ia = bridge_ia; 571 ac = (struct arpcom *)bridge_ia->ia_ifp; 572 } 573 #endif 574 575 if (ia == NULL) { 576 TAILQ_FOREACH(ia, &in_ifaddr, ia_list) { 577 if (isaddr.s_addr != ia->ia_addr.sin_addr.s_addr) 578 continue; 579 if (ia->ia_ifp == m->m_pkthdr.rcvif) 580 break; 581 } 582 } 583 584 if (ia == NULL) { 585 struct ifaddr *ifa; 586 587 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrlist, ifa_list) { 588 if (ifa->ifa_addr->sa_family == AF_INET) 589 break; 590 } 591 if (ifa) 592 ia = (struct in_ifaddr *)ifa; 593 } 594 595 if (ia == NULL) 596 goto out; 597 598 if (!enaddr) 599 enaddr = ac->ac_enaddr; 600 myaddr = ia->ia_addr.sin_addr; 601 602 if (!bcmp((caddr_t)ea->arp_sha, enaddr, sizeof (ea->arp_sha))) 603 goto out; /* it's from me, ignore it. */ 604 if (ETHER_IS_MULTICAST (&ea->arp_sha[0])) 605 if (!bcmp((caddr_t)ea->arp_sha, (caddr_t)etherbroadcastaddr, 606 sizeof (ea->arp_sha))) { 607 log(LOG_ERR, "arp: ether address is broadcast for " 608 "IP address %s!\n", inet_ntoa(isaddr)); 609 goto out; 610 } 611 if (myaddr.s_addr && isaddr.s_addr == myaddr.s_addr) { 612 log(LOG_ERR, 613 "duplicate IP address %s sent from ethernet address %s\n", 614 inet_ntoa(isaddr), ether_sprintf(ea->arp_sha)); 615 itaddr = myaddr; 616 goto reply; 617 } 618 la = arplookup(isaddr.s_addr, itaddr.s_addr == myaddr.s_addr, 0); 619 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { 620 if (sdl->sdl_alen) { 621 if (bcmp(ea->arp_sha, LLADDR(sdl), sdl->sdl_alen)) { 622 if (rt->rt_flags & RTF_PERMANENT_ARP) { 623 log(LOG_WARNING, 624 "arp: attempt to overwrite permanent " 625 "entry for %s by %s on %s\n", 626 inet_ntoa(isaddr), 627 ether_sprintf(ea->arp_sha), 628 ac->ac_if.if_xname); 629 goto out; 630 } else if (rt->rt_ifp != &ac->ac_if) { 631 log(LOG_WARNING, 632 "arp: attempt to overwrite entry for %s " 633 "on %s by %s on %s\n", 634 inet_ntoa(isaddr), rt->rt_ifp->if_xname, 635 ether_sprintf(ea->arp_sha), 636 ac->ac_if.if_xname); 637 goto out; 638 } else { 639 log(LOG_INFO, 640 "arp info overwritten for %s by %s on %s\n", 641 inet_ntoa(isaddr), 642 ether_sprintf(ea->arp_sha), 643 ac->ac_if.if_xname); 644 rt->rt_expire = 1; /* no longer static */ 645 } 646 } 647 } else if (rt->rt_ifp != &ac->ac_if && !(ac->ac_if.if_bridge && 648 (rt->rt_ifp->if_bridge == ac->ac_if.if_bridge))) { 649 log(LOG_WARNING, 650 "arp: attempt to add entry for %s " 651 "on %s by %s on %s\n", 652 inet_ntoa(isaddr), rt->rt_ifp->if_xname, 653 ether_sprintf(ea->arp_sha), 654 ac->ac_if.if_xname); 655 goto out; 656 } 657 bcopy(ea->arp_sha, LLADDR(sdl), 658 sdl->sdl_alen = sizeof(ea->arp_sha)); 659 if (rt->rt_expire) 660 rt->rt_expire = time_second + arpt_keep; 661 rt->rt_flags &= ~RTF_REJECT; 662 la->la_asked = 0; 663 if (la->la_hold) { 664 (*ac->ac_if.if_output)(&ac->ac_if, la->la_hold, 665 rt_key(rt), rt); 666 la->la_hold = 0; 667 } 668 } 669 reply: 670 if (op != ARPOP_REQUEST) { 671 out: 672 m_freem(m); 673 return; 674 } 675 if (itaddr.s_addr == myaddr.s_addr) { 676 /* I am the target */ 677 bcopy(ea->arp_sha, ea->arp_tha, sizeof(ea->arp_sha)); 678 bcopy(enaddr, ea->arp_sha, sizeof(ea->arp_sha)); 679 } else { 680 la = arplookup(itaddr.s_addr, 0, SIN_PROXY); 681 if (la == 0) 682 goto out; 683 rt = la->la_rt; 684 bcopy(ea->arp_sha, ea->arp_tha, sizeof(ea->arp_sha)); 685 sdl = SDL(rt->rt_gateway); 686 bcopy(LLADDR(sdl), ea->arp_sha, sizeof(ea->arp_sha)); 687 } 688 689 bcopy(ea->arp_spa, ea->arp_tpa, sizeof(ea->arp_spa)); 690 bcopy(&itaddr, ea->arp_spa, sizeof(ea->arp_spa)); 691 ea->arp_op = htons(ARPOP_REPLY); 692 ea->arp_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 693 eh = (struct ether_header *)sa.sa_data; 694 bcopy(ea->arp_tha, eh->ether_dhost, sizeof(eh->ether_dhost)); 695 bcopy(enaddr, eh->ether_shost, sizeof(eh->ether_shost)); 696 eh->ether_type = htons(ETHERTYPE_ARP); 697 sa.sa_family = AF_UNSPEC; 698 sa.sa_len = sizeof(sa); 699 (*ac->ac_if.if_output)(&ac->ac_if, m, &sa, (struct rtentry *)0); 700 return; 701 } 702 703 /* 704 * Free an arp entry. 705 */ 706 void 707 arptfree(la) 708 struct llinfo_arp *la; 709 { 710 struct rtentry *rt = la->la_rt; 711 struct sockaddr_dl *sdl; 712 713 if (rt == 0) 714 panic("arptfree"); 715 if (rt->rt_refcnt > 0 && (sdl = SDL(rt->rt_gateway)) && 716 sdl->sdl_family == AF_LINK) { 717 sdl->sdl_alen = 0; 718 la->la_asked = 0; 719 rt->rt_flags &= ~RTF_REJECT; 720 return; 721 } 722 rtrequest(RTM_DELETE, rt_key(rt), (struct sockaddr *)0, rt_mask(rt), 723 0, (struct rtentry **)0); 724 } 725 726 /* 727 * Lookup or enter a new address in arptab. 728 */ 729 struct llinfo_arp * 730 arplookup(addr, create, proxy) 731 u_int32_t addr; 732 int create, proxy; 733 { 734 struct rtentry *rt; 735 static struct sockaddr_inarp sin; 736 737 sin.sin_len = sizeof(sin); 738 sin.sin_family = AF_INET; 739 sin.sin_addr.s_addr = addr; 740 sin.sin_other = proxy ? SIN_PROXY : 0; 741 rt = rtalloc1(sintosa(&sin), create); 742 if (rt == 0) 743 return (0); 744 rt->rt_refcnt--; 745 if ((rt->rt_flags & RTF_GATEWAY) || (rt->rt_flags & RTF_LLINFO) == 0 || 746 rt->rt_gateway->sa_family != AF_LINK) { 747 if (create) { 748 log(LOG_DEBUG, 749 "arplookup: unable to enter address for %s\n", 750 inet_ntoa(sin.sin_addr)); 751 if (rt->rt_refcnt <= 0 && 752 (rt->rt_flags & RTF_CLONED) != 0) { 753 rtrequest(RTM_DELETE, 754 (struct sockaddr *)rt_key(rt), 755 rt->rt_gateway, rt_mask(rt), rt->rt_flags, 756 0); 757 } 758 } 759 return (0); 760 } 761 return ((struct llinfo_arp *)rt->rt_llinfo); 762 } 763 764 int 765 arpioctl(cmd, data) 766 u_long cmd; 767 caddr_t data; 768 { 769 770 return (EOPNOTSUPP); 771 } 772 773 void 774 arp_ifinit(ac, ifa) 775 struct arpcom *ac; 776 struct ifaddr *ifa; 777 { 778 779 /* Warn the user if another station has this IP address. */ 780 arprequest(&ac->ac_if, 781 &(IA_SIN(ifa)->sin_addr.s_addr), 782 &(IA_SIN(ifa)->sin_addr.s_addr), 783 ac->ac_enaddr); 784 ifa->ifa_rtrequest = arp_rtrequest; 785 ifa->ifa_flags |= RTF_CLONING; 786 } 787 788 /* 789 * Called from Ethernet interrupt handlers 790 * when ether packet type ETHERTYPE_REVARP 791 * is received. Common length and type checks are done here, 792 * then the protocol-specific routine is called. 793 */ 794 void 795 revarpinput(m) 796 struct mbuf *m; 797 { 798 struct arphdr *ar; 799 800 if (m->m_len < sizeof(struct arphdr)) 801 goto out; 802 ar = mtod(m, struct arphdr *); 803 if (ntohs(ar->ar_hrd) != ARPHRD_ETHER) 804 goto out; 805 if (m->m_len < sizeof(struct arphdr) + 2 * (ar->ar_hln + ar->ar_pln)) 806 goto out; 807 switch (ntohs(ar->ar_pro)) { 808 809 case ETHERTYPE_IP: 810 case ETHERTYPE_IPTRAILERS: 811 in_revarpinput(m); 812 return; 813 814 default: 815 break; 816 } 817 out: 818 m_freem(m); 819 } 820 821 /* 822 * RARP for Internet protocols on Ethernet. 823 * Algorithm is that given in RFC 903. 824 * We are only using for bootstrap purposes to get an ip address for one of 825 * our interfaces. Thus we support no user-interface. 826 * 827 * Since the contents of the RARP reply are specific to the interface that 828 * sent the request, this code must ensure that they are properly associated. 829 * 830 * Note: also supports ARP via RARP packets, per the RFC. 831 */ 832 void 833 in_revarpinput(m) 834 struct mbuf *m; 835 { 836 struct ifnet *ifp; 837 struct ether_arp *ar; 838 int op; 839 840 ar = mtod(m, struct ether_arp *); 841 op = ntohs(ar->arp_op); 842 switch (op) { 843 case ARPOP_REQUEST: 844 case ARPOP_REPLY: /* per RFC */ 845 in_arpinput(m); 846 return; 847 case ARPOP_REVREPLY: 848 break; 849 case ARPOP_REVREQUEST: /* handled by rarpd(8) */ 850 default: 851 goto out; 852 } 853 if (!revarp_in_progress) 854 goto out; 855 ifp = m->m_pkthdr.rcvif; 856 if (ifp != myip_ifp) /* !same interface */ 857 goto out; 858 if (myip_initialized) 859 goto wake; 860 if (bcmp(ar->arp_tha, ((struct arpcom *)ifp)->ac_enaddr, 861 sizeof(ar->arp_tha))) 862 goto out; 863 bcopy((caddr_t)ar->arp_spa, (caddr_t)&srv_ip, sizeof(srv_ip)); 864 bcopy((caddr_t)ar->arp_tpa, (caddr_t)&myip, sizeof(myip)); 865 myip_initialized = 1; 866 wake: /* Do wakeup every time in case it was missed. */ 867 wakeup((caddr_t)&myip); 868 869 out: 870 m_freem(m); 871 } 872 873 /* 874 * Send a RARP request for the ip address of the specified interface. 875 * The request should be RFC 903-compliant. 876 */ 877 void 878 revarprequest(ifp) 879 struct ifnet *ifp; 880 { 881 struct sockaddr sa; 882 struct mbuf *m; 883 struct ether_header *eh; 884 struct ether_arp *ea; 885 struct arpcom *ac = (struct arpcom *)ifp; 886 887 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 888 return; 889 m->m_len = sizeof(*ea); 890 m->m_pkthdr.len = sizeof(*ea); 891 MH_ALIGN(m, sizeof(*ea)); 892 ea = mtod(m, struct ether_arp *); 893 eh = (struct ether_header *)sa.sa_data; 894 bzero((caddr_t)ea, sizeof(*ea)); 895 bcopy((caddr_t)etherbroadcastaddr, (caddr_t)eh->ether_dhost, 896 sizeof(eh->ether_dhost)); 897 eh->ether_type = htons(ETHERTYPE_REVARP); 898 ea->arp_hrd = htons(ARPHRD_ETHER); 899 ea->arp_pro = htons(ETHERTYPE_IP); 900 ea->arp_hln = sizeof(ea->arp_sha); /* hardware address length */ 901 ea->arp_pln = sizeof(ea->arp_spa); /* protocol address length */ 902 ea->arp_op = htons(ARPOP_REVREQUEST); 903 bcopy((caddr_t)ac->ac_enaddr, (caddr_t)eh->ether_shost, 904 sizeof(ea->arp_tha)); 905 bcopy((caddr_t)ac->ac_enaddr, (caddr_t)ea->arp_sha, 906 sizeof(ea->arp_sha)); 907 bcopy((caddr_t)ac->ac_enaddr, (caddr_t)ea->arp_tha, 908 sizeof(ea->arp_tha)); 909 sa.sa_family = AF_UNSPEC; 910 sa.sa_len = sizeof(sa); 911 ifp->if_output(ifp, m, &sa, (struct rtentry *)0); 912 } 913 914 /* 915 * RARP for the ip address of the specified interface, but also 916 * save the ip address of the server that sent the answer. 917 * Timeout if no response is received. 918 */ 919 int 920 revarpwhoarewe(ifp, serv_in, clnt_in) 921 struct ifnet *ifp; 922 struct in_addr *serv_in; 923 struct in_addr *clnt_in; 924 { 925 int result, count = 20; 926 927 if (myip_initialized) 928 return EIO; 929 930 myip_ifp = ifp; 931 revarp_in_progress = 1; 932 while (count--) { 933 revarprequest(ifp); 934 result = tsleep((caddr_t)&myip, PSOCK, "revarp", hz/2); 935 if (result != EWOULDBLOCK) 936 break; 937 } 938 revarp_in_progress = 0; 939 if (!myip_initialized) 940 return ENETUNREACH; 941 942 bcopy((caddr_t)&srv_ip, serv_in, sizeof(*serv_in)); 943 bcopy((caddr_t)&myip, clnt_in, sizeof(*clnt_in)); 944 return 0; 945 } 946 947 /* For compatibility: only saves interface address. */ 948 int 949 revarpwhoami(in, ifp) 950 struct in_addr *in; 951 struct ifnet *ifp; 952 { 953 struct in_addr server; 954 return (revarpwhoarewe(ifp, &server, in)); 955 } 956 957 958 #ifdef DDB 959 960 #include <machine/db_machdep.h> 961 #include <ddb/db_interface.h> 962 #include <ddb/db_output.h> 963 964 void 965 db_print_sa(sa) 966 struct sockaddr *sa; 967 { 968 int len; 969 u_char *p; 970 971 if (sa == 0) { 972 db_printf("[NULL]"); 973 return; 974 } 975 976 p = (u_char *)sa; 977 len = sa->sa_len; 978 db_printf("["); 979 while (len > 0) { 980 db_printf("%d", *p); 981 p++; 982 len--; 983 if (len) 984 db_printf(","); 985 } 986 db_printf("]\n"); 987 } 988 989 void 990 db_print_ifa(ifa) 991 struct ifaddr *ifa; 992 { 993 if (ifa == 0) 994 return; 995 db_printf(" ifa_addr="); 996 db_print_sa(ifa->ifa_addr); 997 db_printf(" ifa_dsta="); 998 db_print_sa(ifa->ifa_dstaddr); 999 db_printf(" ifa_mask="); 1000 db_print_sa(ifa->ifa_netmask); 1001 db_printf(" flags=0x%x, refcnt=%d, metric=%d\n", 1002 ifa->ifa_flags, ifa->ifa_refcnt, ifa->ifa_metric); 1003 } 1004 1005 void 1006 db_print_llinfo(li) 1007 caddr_t li; 1008 { 1009 struct llinfo_arp *la; 1010 1011 if (li == 0) 1012 return; 1013 la = (struct llinfo_arp *)li; 1014 db_printf(" la_rt=%p la_hold=%p, la_asked=0x%lx\n", 1015 la->la_rt, la->la_hold, la->la_asked); 1016 } 1017 1018 /* 1019 * Function to pass to rn_walktree(). 1020 * Return non-zero error to abort walk. 1021 */ 1022 int 1023 db_show_radix_node(rn, w) 1024 struct radix_node *rn; 1025 void *w; 1026 { 1027 struct rtentry *rt = (struct rtentry *)rn; 1028 1029 db_printf("rtentry=%p", rt); 1030 1031 db_printf(" flags=0x%x refcnt=%d use=%ld expire=%ld\n", 1032 rt->rt_flags, rt->rt_refcnt, rt->rt_use, rt->rt_expire); 1033 1034 db_printf(" key="); db_print_sa(rt_key(rt)); 1035 db_printf(" mask="); db_print_sa(rt_mask(rt)); 1036 db_printf(" gw="); db_print_sa(rt->rt_gateway); 1037 1038 db_printf(" ifp=%p ", rt->rt_ifp); 1039 if (rt->rt_ifp) 1040 db_printf("(%s)", rt->rt_ifp->if_xname); 1041 else 1042 db_printf("(NULL)"); 1043 1044 db_printf(" ifa=%p\n", rt->rt_ifa); 1045 db_print_ifa(rt->rt_ifa); 1046 1047 db_printf(" genmask="); db_print_sa(rt->rt_genmask); 1048 1049 db_printf(" gwroute=%p llinfo=%p\n", rt->rt_gwroute, rt->rt_llinfo); 1050 db_print_llinfo(rt->rt_llinfo); 1051 return (0); 1052 } 1053 1054 /* 1055 * Function to print all the route trees. 1056 * Use this from ddb: "call db_show_arptab" 1057 */ 1058 int 1059 db_show_arptab() 1060 { 1061 struct radix_node_head *rnh; 1062 rnh = rt_tables[AF_INET]; 1063 db_printf("Route tree for AF_INET\n"); 1064 if (rnh == NULL) { 1065 db_printf(" (not initialized)\n"); 1066 return (0); 1067 } 1068 rn_walktree(rnh, db_show_radix_node, NULL); 1069 return (0); 1070 } 1071 #endif 1072 #endif /* INET */ 1073