1 /* $OpenBSD: if_ether.c,v 1.55 2004/12/07 20:38:46 mcbride 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 && ac->ac_if.if_type != IFT_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 !(rt->rt_ifp->if_type == IFT_CARP && 650 rt->rt_ifp->if_carpdev == &ac->ac_if) && 651 !(ac->ac_if.if_type == IFT_CARP && 652 ac->ac_if.if_carpdev == rt->rt_ifp)) { 653 log(LOG_WARNING, 654 "arp: attempt to add entry for %s " 655 "on %s by %s on %s\n", 656 inet_ntoa(isaddr), rt->rt_ifp->if_xname, 657 ether_sprintf(ea->arp_sha), 658 ac->ac_if.if_xname); 659 goto out; 660 } 661 bcopy(ea->arp_sha, LLADDR(sdl), 662 sdl->sdl_alen = sizeof(ea->arp_sha)); 663 if (rt->rt_expire) 664 rt->rt_expire = time_second + arpt_keep; 665 rt->rt_flags &= ~RTF_REJECT; 666 la->la_asked = 0; 667 if (la->la_hold) { 668 (*ac->ac_if.if_output)(&ac->ac_if, la->la_hold, 669 rt_key(rt), rt); 670 la->la_hold = 0; 671 } 672 } 673 reply: 674 if (op != ARPOP_REQUEST) { 675 out: 676 m_freem(m); 677 return; 678 } 679 if (itaddr.s_addr == myaddr.s_addr) { 680 /* I am the target */ 681 bcopy(ea->arp_sha, ea->arp_tha, sizeof(ea->arp_sha)); 682 bcopy(enaddr, ea->arp_sha, sizeof(ea->arp_sha)); 683 } else { 684 la = arplookup(itaddr.s_addr, 0, SIN_PROXY); 685 if (la == 0) 686 goto out; 687 rt = la->la_rt; 688 bcopy(ea->arp_sha, ea->arp_tha, sizeof(ea->arp_sha)); 689 sdl = SDL(rt->rt_gateway); 690 bcopy(LLADDR(sdl), ea->arp_sha, sizeof(ea->arp_sha)); 691 } 692 693 bcopy(ea->arp_spa, ea->arp_tpa, sizeof(ea->arp_spa)); 694 bcopy(&itaddr, ea->arp_spa, sizeof(ea->arp_spa)); 695 ea->arp_op = htons(ARPOP_REPLY); 696 ea->arp_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 697 eh = (struct ether_header *)sa.sa_data; 698 bcopy(ea->arp_tha, eh->ether_dhost, sizeof(eh->ether_dhost)); 699 bcopy(enaddr, eh->ether_shost, sizeof(eh->ether_shost)); 700 eh->ether_type = htons(ETHERTYPE_ARP); 701 sa.sa_family = AF_UNSPEC; 702 sa.sa_len = sizeof(sa); 703 (*ac->ac_if.if_output)(&ac->ac_if, m, &sa, (struct rtentry *)0); 704 return; 705 } 706 707 /* 708 * Free an arp entry. 709 */ 710 void 711 arptfree(la) 712 struct llinfo_arp *la; 713 { 714 struct rtentry *rt = la->la_rt; 715 struct sockaddr_dl *sdl; 716 717 if (rt == 0) 718 panic("arptfree"); 719 if (rt->rt_refcnt > 0 && (sdl = SDL(rt->rt_gateway)) && 720 sdl->sdl_family == AF_LINK) { 721 sdl->sdl_alen = 0; 722 la->la_asked = 0; 723 rt->rt_flags &= ~RTF_REJECT; 724 return; 725 } 726 rtrequest(RTM_DELETE, rt_key(rt), (struct sockaddr *)0, rt_mask(rt), 727 0, (struct rtentry **)0); 728 } 729 730 /* 731 * Lookup or enter a new address in arptab. 732 */ 733 struct llinfo_arp * 734 arplookup(addr, create, proxy) 735 u_int32_t addr; 736 int create, proxy; 737 { 738 struct rtentry *rt; 739 static struct sockaddr_inarp sin; 740 741 sin.sin_len = sizeof(sin); 742 sin.sin_family = AF_INET; 743 sin.sin_addr.s_addr = addr; 744 sin.sin_other = proxy ? SIN_PROXY : 0; 745 rt = rtalloc1(sintosa(&sin), create); 746 if (rt == 0) 747 return (0); 748 rt->rt_refcnt--; 749 if ((rt->rt_flags & RTF_GATEWAY) || (rt->rt_flags & RTF_LLINFO) == 0 || 750 rt->rt_gateway->sa_family != AF_LINK) { 751 if (create) { 752 log(LOG_DEBUG, 753 "arplookup: unable to enter address for %s\n", 754 inet_ntoa(sin.sin_addr)); 755 if (rt->rt_refcnt <= 0 && 756 (rt->rt_flags & RTF_CLONED) != 0) { 757 rtrequest(RTM_DELETE, 758 (struct sockaddr *)rt_key(rt), 759 rt->rt_gateway, rt_mask(rt), rt->rt_flags, 760 0); 761 } 762 } 763 return (0); 764 } 765 return ((struct llinfo_arp *)rt->rt_llinfo); 766 } 767 768 int 769 arpioctl(cmd, data) 770 u_long cmd; 771 caddr_t data; 772 { 773 774 return (EOPNOTSUPP); 775 } 776 777 void 778 arp_ifinit(ac, ifa) 779 struct arpcom *ac; 780 struct ifaddr *ifa; 781 { 782 783 /* Warn the user if another station has this IP address. */ 784 arprequest(&ac->ac_if, 785 &(IA_SIN(ifa)->sin_addr.s_addr), 786 &(IA_SIN(ifa)->sin_addr.s_addr), 787 ac->ac_enaddr); 788 ifa->ifa_rtrequest = arp_rtrequest; 789 ifa->ifa_flags |= RTF_CLONING; 790 } 791 792 /* 793 * Called from Ethernet interrupt handlers 794 * when ether packet type ETHERTYPE_REVARP 795 * is received. Common length and type checks are done here, 796 * then the protocol-specific routine is called. 797 */ 798 void 799 revarpinput(m) 800 struct mbuf *m; 801 { 802 struct arphdr *ar; 803 804 if (m->m_len < sizeof(struct arphdr)) 805 goto out; 806 ar = mtod(m, struct arphdr *); 807 if (ntohs(ar->ar_hrd) != ARPHRD_ETHER) 808 goto out; 809 if (m->m_len < sizeof(struct arphdr) + 2 * (ar->ar_hln + ar->ar_pln)) 810 goto out; 811 switch (ntohs(ar->ar_pro)) { 812 813 case ETHERTYPE_IP: 814 case ETHERTYPE_IPTRAILERS: 815 in_revarpinput(m); 816 return; 817 818 default: 819 break; 820 } 821 out: 822 m_freem(m); 823 } 824 825 /* 826 * RARP for Internet protocols on Ethernet. 827 * Algorithm is that given in RFC 903. 828 * We are only using for bootstrap purposes to get an ip address for one of 829 * our interfaces. Thus we support no user-interface. 830 * 831 * Since the contents of the RARP reply are specific to the interface that 832 * sent the request, this code must ensure that they are properly associated. 833 * 834 * Note: also supports ARP via RARP packets, per the RFC. 835 */ 836 void 837 in_revarpinput(m) 838 struct mbuf *m; 839 { 840 struct ifnet *ifp; 841 struct ether_arp *ar; 842 int op; 843 844 ar = mtod(m, struct ether_arp *); 845 op = ntohs(ar->arp_op); 846 switch (op) { 847 case ARPOP_REQUEST: 848 case ARPOP_REPLY: /* per RFC */ 849 in_arpinput(m); 850 return; 851 case ARPOP_REVREPLY: 852 break; 853 case ARPOP_REVREQUEST: /* handled by rarpd(8) */ 854 default: 855 goto out; 856 } 857 if (!revarp_in_progress) 858 goto out; 859 ifp = m->m_pkthdr.rcvif; 860 if (ifp != myip_ifp) /* !same interface */ 861 goto out; 862 if (myip_initialized) 863 goto wake; 864 if (bcmp(ar->arp_tha, ((struct arpcom *)ifp)->ac_enaddr, 865 sizeof(ar->arp_tha))) 866 goto out; 867 bcopy((caddr_t)ar->arp_spa, (caddr_t)&srv_ip, sizeof(srv_ip)); 868 bcopy((caddr_t)ar->arp_tpa, (caddr_t)&myip, sizeof(myip)); 869 myip_initialized = 1; 870 wake: /* Do wakeup every time in case it was missed. */ 871 wakeup((caddr_t)&myip); 872 873 out: 874 m_freem(m); 875 } 876 877 /* 878 * Send a RARP request for the ip address of the specified interface. 879 * The request should be RFC 903-compliant. 880 */ 881 void 882 revarprequest(ifp) 883 struct ifnet *ifp; 884 { 885 struct sockaddr sa; 886 struct mbuf *m; 887 struct ether_header *eh; 888 struct ether_arp *ea; 889 struct arpcom *ac = (struct arpcom *)ifp; 890 891 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 892 return; 893 m->m_len = sizeof(*ea); 894 m->m_pkthdr.len = sizeof(*ea); 895 MH_ALIGN(m, sizeof(*ea)); 896 ea = mtod(m, struct ether_arp *); 897 eh = (struct ether_header *)sa.sa_data; 898 bzero((caddr_t)ea, sizeof(*ea)); 899 bcopy((caddr_t)etherbroadcastaddr, (caddr_t)eh->ether_dhost, 900 sizeof(eh->ether_dhost)); 901 eh->ether_type = htons(ETHERTYPE_REVARP); 902 ea->arp_hrd = htons(ARPHRD_ETHER); 903 ea->arp_pro = htons(ETHERTYPE_IP); 904 ea->arp_hln = sizeof(ea->arp_sha); /* hardware address length */ 905 ea->arp_pln = sizeof(ea->arp_spa); /* protocol address length */ 906 ea->arp_op = htons(ARPOP_REVREQUEST); 907 bcopy((caddr_t)ac->ac_enaddr, (caddr_t)eh->ether_shost, 908 sizeof(ea->arp_tha)); 909 bcopy((caddr_t)ac->ac_enaddr, (caddr_t)ea->arp_sha, 910 sizeof(ea->arp_sha)); 911 bcopy((caddr_t)ac->ac_enaddr, (caddr_t)ea->arp_tha, 912 sizeof(ea->arp_tha)); 913 sa.sa_family = AF_UNSPEC; 914 sa.sa_len = sizeof(sa); 915 ifp->if_output(ifp, m, &sa, (struct rtentry *)0); 916 } 917 918 /* 919 * RARP for the ip address of the specified interface, but also 920 * save the ip address of the server that sent the answer. 921 * Timeout if no response is received. 922 */ 923 int 924 revarpwhoarewe(ifp, serv_in, clnt_in) 925 struct ifnet *ifp; 926 struct in_addr *serv_in; 927 struct in_addr *clnt_in; 928 { 929 int result, count = 20; 930 931 if (myip_initialized) 932 return EIO; 933 934 myip_ifp = ifp; 935 revarp_in_progress = 1; 936 while (count--) { 937 revarprequest(ifp); 938 result = tsleep((caddr_t)&myip, PSOCK, "revarp", hz/2); 939 if (result != EWOULDBLOCK) 940 break; 941 } 942 revarp_in_progress = 0; 943 if (!myip_initialized) 944 return ENETUNREACH; 945 946 bcopy((caddr_t)&srv_ip, serv_in, sizeof(*serv_in)); 947 bcopy((caddr_t)&myip, clnt_in, sizeof(*clnt_in)); 948 return 0; 949 } 950 951 /* For compatibility: only saves interface address. */ 952 int 953 revarpwhoami(in, ifp) 954 struct in_addr *in; 955 struct ifnet *ifp; 956 { 957 struct in_addr server; 958 return (revarpwhoarewe(ifp, &server, in)); 959 } 960 961 962 #ifdef DDB 963 964 #include <machine/db_machdep.h> 965 #include <ddb/db_interface.h> 966 #include <ddb/db_output.h> 967 968 void 969 db_print_sa(sa) 970 struct sockaddr *sa; 971 { 972 int len; 973 u_char *p; 974 975 if (sa == 0) { 976 db_printf("[NULL]"); 977 return; 978 } 979 980 p = (u_char *)sa; 981 len = sa->sa_len; 982 db_printf("["); 983 while (len > 0) { 984 db_printf("%d", *p); 985 p++; 986 len--; 987 if (len) 988 db_printf(","); 989 } 990 db_printf("]\n"); 991 } 992 993 void 994 db_print_ifa(ifa) 995 struct ifaddr *ifa; 996 { 997 if (ifa == 0) 998 return; 999 db_printf(" ifa_addr="); 1000 db_print_sa(ifa->ifa_addr); 1001 db_printf(" ifa_dsta="); 1002 db_print_sa(ifa->ifa_dstaddr); 1003 db_printf(" ifa_mask="); 1004 db_print_sa(ifa->ifa_netmask); 1005 db_printf(" flags=0x%x, refcnt=%d, metric=%d\n", 1006 ifa->ifa_flags, ifa->ifa_refcnt, ifa->ifa_metric); 1007 } 1008 1009 void 1010 db_print_llinfo(li) 1011 caddr_t li; 1012 { 1013 struct llinfo_arp *la; 1014 1015 if (li == 0) 1016 return; 1017 la = (struct llinfo_arp *)li; 1018 db_printf(" la_rt=%p la_hold=%p, la_asked=0x%lx\n", 1019 la->la_rt, la->la_hold, la->la_asked); 1020 } 1021 1022 /* 1023 * Function to pass to rn_walktree(). 1024 * Return non-zero error to abort walk. 1025 */ 1026 int 1027 db_show_radix_node(rn, w) 1028 struct radix_node *rn; 1029 void *w; 1030 { 1031 struct rtentry *rt = (struct rtentry *)rn; 1032 1033 db_printf("rtentry=%p", rt); 1034 1035 db_printf(" flags=0x%x refcnt=%d use=%ld expire=%ld\n", 1036 rt->rt_flags, rt->rt_refcnt, rt->rt_use, rt->rt_expire); 1037 1038 db_printf(" key="); db_print_sa(rt_key(rt)); 1039 db_printf(" mask="); db_print_sa(rt_mask(rt)); 1040 db_printf(" gw="); db_print_sa(rt->rt_gateway); 1041 1042 db_printf(" ifp=%p ", rt->rt_ifp); 1043 if (rt->rt_ifp) 1044 db_printf("(%s)", rt->rt_ifp->if_xname); 1045 else 1046 db_printf("(NULL)"); 1047 1048 db_printf(" ifa=%p\n", rt->rt_ifa); 1049 db_print_ifa(rt->rt_ifa); 1050 1051 db_printf(" genmask="); db_print_sa(rt->rt_genmask); 1052 1053 db_printf(" gwroute=%p llinfo=%p\n", rt->rt_gwroute, rt->rt_llinfo); 1054 db_print_llinfo(rt->rt_llinfo); 1055 return (0); 1056 } 1057 1058 /* 1059 * Function to print all the route trees. 1060 * Use this from ddb: "call db_show_arptab" 1061 */ 1062 int 1063 db_show_arptab() 1064 { 1065 struct radix_node_head *rnh; 1066 rnh = rt_tables[AF_INET]; 1067 db_printf("Route tree for AF_INET\n"); 1068 if (rnh == NULL) { 1069 db_printf(" (not initialized)\n"); 1070 return (0); 1071 } 1072 rn_walktree(rnh, db_show_radix_node, NULL); 1073 return (0); 1074 } 1075 #endif 1076 #endif /* INET */ 1077