1 /* $OpenBSD: if_ether.c,v 1.75 2008/06/06 13:29:43 henning 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, 0); 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 = pseudo_AF_HDRCMPLT; 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 if (la == NULL) 391 log(LOG_DEBUG, "arpresolve: %s: route without link " 392 "local address\n", inet_ntoa(SIN(dst)->sin_addr)); 393 } else { 394 if ((la = arplookup(SIN(dst)->sin_addr.s_addr, 1, 0)) != NULL) 395 rt = la->la_rt; 396 else 397 log(LOG_DEBUG, 398 "arpresolve: %s: can't allocate llinfo\n", 399 inet_ntoa(SIN(dst)->sin_addr)); 400 } 401 if (la == 0 || rt == 0) { 402 m_freem(m); 403 return (0); 404 } 405 sdl = SDL(rt->rt_gateway); 406 /* 407 * Check the address family and length is valid, the address 408 * is resolved; otherwise, try to resolve. 409 */ 410 if ((rt->rt_expire == 0 || rt->rt_expire > time_second) && 411 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 412 bcopy(LLADDR(sdl), desten, sdl->sdl_alen); 413 return 1; 414 } 415 if (((struct ifnet *)ac)->if_flags & IFF_NOARP) 416 return 0; 417 418 /* 419 * There is an arptab entry, but no ethernet address 420 * response yet. Replace the held mbuf with this 421 * latest one. 422 */ 423 if (la->la_hold) 424 m_freem(la->la_hold); 425 la->la_hold = m; 426 /* 427 * Re-send the ARP request when appropriate. 428 */ 429 #ifdef DIAGNOSTIC 430 if (rt->rt_expire == 0) { 431 /* This should never happen. (Should it? -gwr) */ 432 printf("arpresolve: unresolved and rt_expire == 0\n"); 433 /* Set expiration time to now (expired). */ 434 rt->rt_expire = time_second; 435 } 436 #endif 437 if (rt->rt_expire) { 438 rt->rt_flags &= ~RTF_REJECT; 439 if (la->la_asked == 0 || rt->rt_expire != time_second) { 440 rt->rt_expire = time_second; 441 if (la->la_asked++ < arp_maxtries) 442 arprequest(&ac->ac_if, 443 &(SIN(rt->rt_ifa->ifa_addr)->sin_addr.s_addr), 444 &(SIN(dst)->sin_addr.s_addr), 445 #if NCARP > 0 446 (rt->rt_ifp->if_type == IFT_CARP) ? 447 ((struct arpcom *) rt->rt_ifp->if_softc 448 )->ac_enaddr : 449 #endif 450 ac->ac_enaddr); 451 else { 452 rt->rt_flags |= RTF_REJECT; 453 rt->rt_expire += arpt_down; 454 la->la_asked = 0; 455 } 456 } 457 } 458 return (0); 459 } 460 461 /* 462 * Common length and type checks are done here, 463 * then the protocol-specific routine is called. 464 */ 465 void 466 arpintr() 467 { 468 struct mbuf *m; 469 struct arphdr *ar; 470 int s, len; 471 472 for (;;) { 473 s = splnet(); 474 IF_DEQUEUE(&arpintrq, m); 475 splx(s); 476 if (m == NULL) 477 break; 478 #ifdef DIAGNOSTIC 479 if ((m->m_flags & M_PKTHDR) == 0) 480 panic("arpintr"); 481 #endif 482 483 len = sizeof(struct arphdr); 484 if (m->m_len < len && (m = m_pullup(m, len)) == NULL) 485 continue; 486 487 ar = mtod(m, struct arphdr *); 488 if (ntohs(ar->ar_hrd) != ARPHRD_ETHER) { 489 m_freem(m); 490 continue; 491 } 492 493 len += 2 * (ar->ar_hln + ar->ar_pln); 494 if (m->m_len < len && (m = m_pullup(m, len)) == NULL) 495 continue; 496 497 switch (ntohs(ar->ar_pro)) { 498 case ETHERTYPE_IP: 499 case ETHERTYPE_IPTRAILERS: 500 in_arpinput(m); 501 continue; 502 } 503 m_freem(m); 504 } 505 } 506 507 /* 508 * ARP for Internet protocols on Ethernet. 509 * Algorithm is that given in RFC 826. 510 * In addition, a sanity check is performed on the sender 511 * protocol address, to catch impersonators. 512 * We no longer handle negotiations for use of trailer protocol: 513 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 514 * along with IP replies if we wanted trailers sent to us, 515 * and also sent them in response to IP replies. 516 * This allowed either end to announce the desire to receive 517 * trailer packets. 518 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 519 * but formerly didn't normally send requests. 520 */ 521 void 522 in_arpinput(m) 523 struct mbuf *m; 524 { 525 struct ether_arp *ea; 526 struct arpcom *ac = (struct arpcom *)m->m_pkthdr.rcvif; 527 struct ether_header *eh; 528 struct llinfo_arp *la = 0; 529 struct rtentry *rt; 530 struct in_ifaddr *ia; 531 #if NBRIDGE > 0 532 struct in_ifaddr *bridge_ia = NULL; 533 #endif 534 struct sockaddr_dl *sdl; 535 struct sockaddr sa; 536 struct in_addr isaddr, itaddr, myaddr; 537 u_int8_t *enaddr = NULL; 538 #if NCARP > 0 539 u_int8_t *ether_shost = NULL; 540 #endif 541 int op; 542 543 ea = mtod(m, struct ether_arp *); 544 op = ntohs(ea->arp_op); 545 if ((op != ARPOP_REQUEST) && (op != ARPOP_REPLY)) 546 goto out; 547 #if notyet 548 if ((op == ARPOP_REPLY) && (m->m_flags & (M_BCAST|M_MCAST))) { 549 log(LOG_ERR, 550 "arp: received reply to broadcast or multicast address\n"); 551 goto out; 552 } 553 #endif 554 555 bcopy((caddr_t)ea->arp_tpa, (caddr_t)&itaddr, sizeof(itaddr)); 556 bcopy((caddr_t)ea->arp_spa, (caddr_t)&isaddr, sizeof(isaddr)); 557 558 TAILQ_FOREACH(ia, &in_ifaddr, ia_list) { 559 if (itaddr.s_addr != ia->ia_addr.sin_addr.s_addr) 560 continue; 561 562 #if NCARP > 0 563 if (ia->ia_ifp->if_type == IFT_CARP && 564 ((ia->ia_ifp->if_flags & (IFF_UP|IFF_RUNNING)) == 565 (IFF_UP|IFF_RUNNING))) { 566 if (ia->ia_ifp == m->m_pkthdr.rcvif && 567 (op == ARPOP_REPLY || 568 carp_iamatch(ia, ea->arp_sha, 569 &enaddr, ðer_shost))) 570 break; 571 } else 572 #endif 573 if (ia->ia_ifp == m->m_pkthdr.rcvif) 574 break; 575 #if NBRIDGE > 0 576 /* 577 * If the interface we received the packet on 578 * is part of a bridge, check to see if we need 579 * to "bridge" the packet to ourselves at this 580 * layer. Note we still prefer a perfect match, 581 * but allow this weaker match if necessary. 582 */ 583 if (m->m_pkthdr.rcvif->if_bridge != NULL) { 584 if (m->m_pkthdr.rcvif->if_bridge == 585 ia->ia_ifp->if_bridge) 586 bridge_ia = ia; 587 #if NCARP > 0 588 else if (ia->ia_ifp->if_carpdev != NULL && 589 m->m_pkthdr.rcvif->if_bridge == 590 ia->ia_ifp->if_carpdev->if_bridge && 591 carp_iamatch(ia, ea->arp_sha, 592 &enaddr, ðer_shost)) 593 bridge_ia = ia; 594 #endif 595 } 596 #endif 597 } 598 599 #if NBRIDGE > 0 600 if (ia == NULL && bridge_ia != NULL) { 601 ia = bridge_ia; 602 ac = (struct arpcom *)bridge_ia->ia_ifp; 603 } 604 #endif 605 606 if (ia == NULL) { 607 TAILQ_FOREACH(ia, &in_ifaddr, ia_list) { 608 if (isaddr.s_addr != ia->ia_addr.sin_addr.s_addr) 609 continue; 610 if (ia->ia_ifp == m->m_pkthdr.rcvif) 611 break; 612 } 613 } 614 615 if (ia == NULL && m->m_pkthdr.rcvif->if_type != IFT_CARP) { 616 struct ifaddr *ifa; 617 618 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrlist, ifa_list) { 619 if (ifa->ifa_addr->sa_family == AF_INET) 620 break; 621 } 622 if (ifa) 623 ia = (struct in_ifaddr *)ifa; 624 } 625 626 if (ia == NULL) 627 goto out; 628 629 if (!enaddr) 630 enaddr = ac->ac_enaddr; 631 myaddr = ia->ia_addr.sin_addr; 632 633 if (!bcmp((caddr_t)ea->arp_sha, enaddr, sizeof (ea->arp_sha))) 634 goto out; /* it's from me, ignore it. */ 635 if (ETHER_IS_MULTICAST (&ea->arp_sha[0])) 636 if (!bcmp((caddr_t)ea->arp_sha, (caddr_t)etherbroadcastaddr, 637 sizeof (ea->arp_sha))) { 638 log(LOG_ERR, "arp: ether address is broadcast for " 639 "IP address %s!\n", inet_ntoa(isaddr)); 640 goto out; 641 } 642 if (myaddr.s_addr && isaddr.s_addr == myaddr.s_addr) { 643 log(LOG_ERR, 644 "duplicate IP address %s sent from ethernet address %s\n", 645 inet_ntoa(isaddr), ether_sprintf(ea->arp_sha)); 646 itaddr = myaddr; 647 goto reply; 648 } 649 la = arplookup(isaddr.s_addr, itaddr.s_addr == myaddr.s_addr, 0); 650 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { 651 if (sdl->sdl_alen) { 652 if (bcmp(ea->arp_sha, LLADDR(sdl), sdl->sdl_alen)) { 653 if (rt->rt_flags & RTF_PERMANENT_ARP) { 654 log(LOG_WARNING, 655 "arp: attempt to overwrite permanent " 656 "entry for %s by %s on %s\n", 657 inet_ntoa(isaddr), 658 ether_sprintf(ea->arp_sha), 659 ac->ac_if.if_xname); 660 goto out; 661 } else if (rt->rt_ifp != &ac->ac_if) { 662 log(LOG_WARNING, 663 "arp: attempt to overwrite entry for %s " 664 "on %s by %s on %s\n", 665 inet_ntoa(isaddr), rt->rt_ifp->if_xname, 666 ether_sprintf(ea->arp_sha), 667 ac->ac_if.if_xname); 668 goto out; 669 } else { 670 log(LOG_INFO, 671 "arp info overwritten for %s by %s on %s\n", 672 inet_ntoa(isaddr), 673 ether_sprintf(ea->arp_sha), 674 ac->ac_if.if_xname); 675 rt->rt_expire = 1; /* no longer static */ 676 } 677 } 678 } else if (rt->rt_ifp != &ac->ac_if && !(ac->ac_if.if_bridge && 679 (rt->rt_ifp->if_bridge == ac->ac_if.if_bridge)) && 680 !(rt->rt_ifp->if_type == IFT_CARP && 681 rt->rt_ifp->if_carpdev == &ac->ac_if) && 682 !(ac->ac_if.if_type == IFT_CARP && 683 ac->ac_if.if_carpdev == rt->rt_ifp)) { 684 log(LOG_WARNING, 685 "arp: attempt to add entry for %s " 686 "on %s by %s on %s\n", 687 inet_ntoa(isaddr), rt->rt_ifp->if_xname, 688 ether_sprintf(ea->arp_sha), 689 ac->ac_if.if_xname); 690 goto out; 691 } 692 bcopy(ea->arp_sha, LLADDR(sdl), 693 sdl->sdl_alen = sizeof(ea->arp_sha)); 694 if (rt->rt_expire) 695 rt->rt_expire = time_second + arpt_keep; 696 rt->rt_flags &= ~RTF_REJECT; 697 la->la_asked = 0; 698 if (la->la_hold) { 699 struct mbuf *n = la->la_hold; 700 la->la_hold = NULL; 701 (*ac->ac_if.if_output)(&ac->ac_if, n, rt_key(rt), rt); 702 if (la->la_hold == n) { 703 /* n is back in la_hold. Discard. */ 704 m_freem(la->la_hold); 705 la->la_hold = NULL; 706 } 707 } 708 } 709 reply: 710 if (op != ARPOP_REQUEST) { 711 out: 712 m_freem(m); 713 return; 714 } 715 if (itaddr.s_addr == myaddr.s_addr) { 716 /* I am the target */ 717 bcopy(ea->arp_sha, ea->arp_tha, sizeof(ea->arp_sha)); 718 bcopy(enaddr, ea->arp_sha, sizeof(ea->arp_sha)); 719 } else { 720 la = arplookup(itaddr.s_addr, 0, SIN_PROXY); 721 if (la == 0) 722 goto out; 723 rt = la->la_rt; 724 if (rt->rt_ifp->if_type == IFT_CARP && 725 m->m_pkthdr.rcvif->if_type != IFT_CARP) 726 goto out; 727 bcopy(ea->arp_sha, ea->arp_tha, sizeof(ea->arp_sha)); 728 sdl = SDL(rt->rt_gateway); 729 bcopy(LLADDR(sdl), ea->arp_sha, sizeof(ea->arp_sha)); 730 } 731 732 bcopy(ea->arp_spa, ea->arp_tpa, sizeof(ea->arp_spa)); 733 bcopy(&itaddr, ea->arp_spa, sizeof(ea->arp_spa)); 734 ea->arp_op = htons(ARPOP_REPLY); 735 ea->arp_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 736 eh = (struct ether_header *)sa.sa_data; 737 bcopy(ea->arp_tha, eh->ether_dhost, sizeof(eh->ether_dhost)); 738 #if NCARP > 0 739 if (ether_shost) 740 enaddr = ether_shost; 741 #endif 742 bcopy(enaddr, eh->ether_shost, sizeof(eh->ether_shost)); 743 744 eh->ether_type = htons(ETHERTYPE_ARP); 745 sa.sa_family = pseudo_AF_HDRCMPLT; 746 sa.sa_len = sizeof(sa); 747 (*ac->ac_if.if_output)(&ac->ac_if, m, &sa, (struct rtentry *)0); 748 return; 749 } 750 751 /* 752 * Free an arp entry. 753 */ 754 void 755 arptfree(la) 756 struct llinfo_arp *la; 757 { 758 struct rtentry *rt = la->la_rt; 759 struct sockaddr_dl *sdl; 760 struct rt_addrinfo info; 761 762 if (rt == 0) 763 panic("arptfree"); 764 if (rt->rt_refcnt > 0 && (sdl = SDL(rt->rt_gateway)) && 765 sdl->sdl_family == AF_LINK) { 766 sdl->sdl_alen = 0; 767 la->la_asked = 0; 768 rt->rt_flags &= ~RTF_REJECT; 769 return; 770 } 771 bzero(&info, sizeof(info)); 772 info.rti_info[RTAX_DST] = rt_key(rt); 773 info.rti_info[RTAX_NETMASK] = rt_mask(rt); 774 775 rtrequest1(RTM_DELETE, &info, rt->rt_priority, NULL, 0); 776 } 777 778 /* 779 * Lookup or enter a new address in arptab. 780 */ 781 struct llinfo_arp * 782 arplookup(addr, create, proxy) 783 u_int32_t addr; 784 int create, proxy; 785 { 786 struct rtentry *rt; 787 static struct sockaddr_inarp sin; 788 789 sin.sin_len = sizeof(sin); 790 sin.sin_family = AF_INET; 791 sin.sin_addr.s_addr = addr; 792 sin.sin_other = proxy ? SIN_PROXY : 0; 793 rt = rtalloc1(sintosa(&sin), create, 0); 794 if (rt == 0) 795 return (0); 796 rt->rt_refcnt--; 797 if ((rt->rt_flags & RTF_GATEWAY) || (rt->rt_flags & RTF_LLINFO) == 0 || 798 rt->rt_gateway->sa_family != AF_LINK) { 799 if (create) { 800 if (rt->rt_refcnt <= 0 && 801 (rt->rt_flags & RTF_CLONED) != 0) { 802 struct rt_addrinfo info; 803 804 bzero(&info, sizeof(info)); 805 info.rti_info[RTAX_DST] = rt_key(rt); 806 info.rti_info[RTAX_GATEWAY] = rt->rt_gateway; 807 info.rti_info[RTAX_NETMASK] = rt_mask(rt); 808 809 rtrequest1(RTM_DELETE, &info, rt->rt_priority, 810 NULL, 0); 811 } 812 } 813 return (0); 814 } 815 return ((struct llinfo_arp *)rt->rt_llinfo); 816 } 817 818 int 819 arpioctl(cmd, data) 820 u_long cmd; 821 caddr_t data; 822 { 823 824 return (EOPNOTSUPP); 825 } 826 827 void 828 arp_ifinit(ac, ifa) 829 struct arpcom *ac; 830 struct ifaddr *ifa; 831 { 832 833 /* Warn the user if another station has this IP address. */ 834 arprequest(&ac->ac_if, 835 &(IA_SIN(ifa)->sin_addr.s_addr), 836 &(IA_SIN(ifa)->sin_addr.s_addr), 837 ac->ac_enaddr); 838 ifa->ifa_rtrequest = arp_rtrequest; 839 ifa->ifa_flags |= RTF_CLONING; 840 } 841 842 /* 843 * Called from Ethernet interrupt handlers 844 * when ether packet type ETHERTYPE_REVARP 845 * is received. Common length and type checks are done here, 846 * then the protocol-specific routine is called. 847 */ 848 void 849 revarpinput(m) 850 struct mbuf *m; 851 { 852 struct arphdr *ar; 853 854 if (m->m_len < sizeof(struct arphdr)) 855 goto out; 856 ar = mtod(m, struct arphdr *); 857 if (ntohs(ar->ar_hrd) != ARPHRD_ETHER) 858 goto out; 859 if (m->m_len < sizeof(struct arphdr) + 2 * (ar->ar_hln + ar->ar_pln)) 860 goto out; 861 switch (ntohs(ar->ar_pro)) { 862 863 case ETHERTYPE_IP: 864 case ETHERTYPE_IPTRAILERS: 865 in_revarpinput(m); 866 return; 867 868 default: 869 break; 870 } 871 out: 872 m_freem(m); 873 } 874 875 /* 876 * RARP for Internet protocols on Ethernet. 877 * Algorithm is that given in RFC 903. 878 * We are only using for bootstrap purposes to get an ip address for one of 879 * our interfaces. Thus we support no user-interface. 880 * 881 * Since the contents of the RARP reply are specific to the interface that 882 * sent the request, this code must ensure that they are properly associated. 883 * 884 * Note: also supports ARP via RARP packets, per the RFC. 885 */ 886 void 887 in_revarpinput(m) 888 struct mbuf *m; 889 { 890 struct ifnet *ifp; 891 struct ether_arp *ar; 892 int op; 893 894 ar = mtod(m, struct ether_arp *); 895 op = ntohs(ar->arp_op); 896 switch (op) { 897 case ARPOP_REQUEST: 898 case ARPOP_REPLY: /* per RFC */ 899 in_arpinput(m); 900 return; 901 case ARPOP_REVREPLY: 902 break; 903 case ARPOP_REVREQUEST: /* handled by rarpd(8) */ 904 default: 905 goto out; 906 } 907 if (!revarp_in_progress) 908 goto out; 909 ifp = m->m_pkthdr.rcvif; 910 if (ifp != myip_ifp) /* !same interface */ 911 goto out; 912 if (myip_initialized) 913 goto wake; 914 if (bcmp(ar->arp_tha, ((struct arpcom *)ifp)->ac_enaddr, 915 sizeof(ar->arp_tha))) 916 goto out; 917 bcopy((caddr_t)ar->arp_spa, (caddr_t)&srv_ip, sizeof(srv_ip)); 918 bcopy((caddr_t)ar->arp_tpa, (caddr_t)&myip, sizeof(myip)); 919 myip_initialized = 1; 920 wake: /* Do wakeup every time in case it was missed. */ 921 wakeup((caddr_t)&myip); 922 923 out: 924 m_freem(m); 925 } 926 927 /* 928 * Send a RARP request for the ip address of the specified interface. 929 * The request should be RFC 903-compliant. 930 */ 931 void 932 revarprequest(ifp) 933 struct ifnet *ifp; 934 { 935 struct sockaddr sa; 936 struct mbuf *m; 937 struct ether_header *eh; 938 struct ether_arp *ea; 939 struct arpcom *ac = (struct arpcom *)ifp; 940 941 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 942 return; 943 m->m_len = sizeof(*ea); 944 m->m_pkthdr.len = sizeof(*ea); 945 MH_ALIGN(m, sizeof(*ea)); 946 ea = mtod(m, struct ether_arp *); 947 eh = (struct ether_header *)sa.sa_data; 948 bzero((caddr_t)ea, sizeof(*ea)); 949 bcopy((caddr_t)etherbroadcastaddr, (caddr_t)eh->ether_dhost, 950 sizeof(eh->ether_dhost)); 951 eh->ether_type = htons(ETHERTYPE_REVARP); 952 ea->arp_hrd = htons(ARPHRD_ETHER); 953 ea->arp_pro = htons(ETHERTYPE_IP); 954 ea->arp_hln = sizeof(ea->arp_sha); /* hardware address length */ 955 ea->arp_pln = sizeof(ea->arp_spa); /* protocol address length */ 956 ea->arp_op = htons(ARPOP_REVREQUEST); 957 bcopy((caddr_t)ac->ac_enaddr, (caddr_t)eh->ether_shost, 958 sizeof(ea->arp_tha)); 959 bcopy((caddr_t)ac->ac_enaddr, (caddr_t)ea->arp_sha, 960 sizeof(ea->arp_sha)); 961 bcopy((caddr_t)ac->ac_enaddr, (caddr_t)ea->arp_tha, 962 sizeof(ea->arp_tha)); 963 sa.sa_family = pseudo_AF_HDRCMPLT; 964 sa.sa_len = sizeof(sa); 965 ifp->if_output(ifp, m, &sa, (struct rtentry *)0); 966 } 967 968 /* 969 * RARP for the ip address of the specified interface, but also 970 * save the ip address of the server that sent the answer. 971 * Timeout if no response is received. 972 */ 973 int 974 revarpwhoarewe(ifp, serv_in, clnt_in) 975 struct ifnet *ifp; 976 struct in_addr *serv_in; 977 struct in_addr *clnt_in; 978 { 979 int result, count = 20; 980 981 if (myip_initialized) 982 return EIO; 983 984 myip_ifp = ifp; 985 revarp_in_progress = 1; 986 while (count--) { 987 revarprequest(ifp); 988 result = tsleep((caddr_t)&myip, PSOCK, "revarp", hz/2); 989 if (result != EWOULDBLOCK) 990 break; 991 } 992 revarp_in_progress = 0; 993 if (!myip_initialized) 994 return ENETUNREACH; 995 996 bcopy((caddr_t)&srv_ip, serv_in, sizeof(*serv_in)); 997 bcopy((caddr_t)&myip, clnt_in, sizeof(*clnt_in)); 998 return 0; 999 } 1000 1001 /* For compatibility: only saves interface address. */ 1002 int 1003 revarpwhoami(in, ifp) 1004 struct in_addr *in; 1005 struct ifnet *ifp; 1006 { 1007 struct in_addr server; 1008 return (revarpwhoarewe(ifp, &server, in)); 1009 } 1010 1011 1012 #ifdef DDB 1013 1014 #include <machine/db_machdep.h> 1015 #include <ddb/db_interface.h> 1016 #include <ddb/db_output.h> 1017 1018 void 1019 db_print_sa(sa) 1020 struct sockaddr *sa; 1021 { 1022 int len; 1023 u_char *p; 1024 1025 if (sa == 0) { 1026 db_printf("[NULL]"); 1027 return; 1028 } 1029 1030 p = (u_char *)sa; 1031 len = sa->sa_len; 1032 db_printf("["); 1033 while (len > 0) { 1034 db_printf("%d", *p); 1035 p++; 1036 len--; 1037 if (len) 1038 db_printf(","); 1039 } 1040 db_printf("]\n"); 1041 } 1042 1043 void 1044 db_print_ifa(ifa) 1045 struct ifaddr *ifa; 1046 { 1047 if (ifa == 0) 1048 return; 1049 db_printf(" ifa_addr="); 1050 db_print_sa(ifa->ifa_addr); 1051 db_printf(" ifa_dsta="); 1052 db_print_sa(ifa->ifa_dstaddr); 1053 db_printf(" ifa_mask="); 1054 db_print_sa(ifa->ifa_netmask); 1055 db_printf(" flags=0x%x, refcnt=%d, metric=%d\n", 1056 ifa->ifa_flags, ifa->ifa_refcnt, ifa->ifa_metric); 1057 } 1058 1059 void 1060 db_print_llinfo(li) 1061 caddr_t li; 1062 { 1063 struct llinfo_arp *la; 1064 1065 if (li == 0) 1066 return; 1067 la = (struct llinfo_arp *)li; 1068 db_printf(" la_rt=%p la_hold=%p, la_asked=0x%lx\n", 1069 la->la_rt, la->la_hold, la->la_asked); 1070 } 1071 1072 /* 1073 * Function to pass to rn_walktree(). 1074 * Return non-zero error to abort walk. 1075 */ 1076 int 1077 db_show_radix_node(rn, w) 1078 struct radix_node *rn; 1079 void *w; 1080 { 1081 struct rtentry *rt = (struct rtentry *)rn; 1082 1083 db_printf("rtentry=%p", rt); 1084 1085 db_printf(" flags=0x%x refcnt=%d use=%ld expire=%ld\n", 1086 rt->rt_flags, rt->rt_refcnt, rt->rt_use, rt->rt_expire); 1087 1088 db_printf(" key="); db_print_sa(rt_key(rt)); 1089 db_printf(" mask="); db_print_sa(rt_mask(rt)); 1090 db_printf(" gw="); db_print_sa(rt->rt_gateway); 1091 1092 db_printf(" ifp=%p ", rt->rt_ifp); 1093 if (rt->rt_ifp) 1094 db_printf("(%s)", rt->rt_ifp->if_xname); 1095 else 1096 db_printf("(NULL)"); 1097 1098 db_printf(" ifa=%p\n", rt->rt_ifa); 1099 db_print_ifa(rt->rt_ifa); 1100 1101 db_printf(" genmask="); db_print_sa(rt->rt_genmask); 1102 1103 db_printf(" gwroute=%p llinfo=%p\n", rt->rt_gwroute, rt->rt_llinfo); 1104 db_print_llinfo(rt->rt_llinfo); 1105 return (0); 1106 } 1107 1108 /* 1109 * Function to print all the route trees. 1110 * Use this from ddb: "call db_show_arptab" 1111 */ 1112 int 1113 db_show_arptab() 1114 { 1115 struct radix_node_head *rnh; 1116 rnh = rt_gettable(AF_INET, 0); 1117 db_printf("Route tree for AF_INET\n"); 1118 if (rnh == NULL) { 1119 db_printf(" (not initialized)\n"); 1120 return (0); 1121 } 1122 rn_walktree(rnh, db_show_radix_node, NULL); 1123 return (0); 1124 } 1125 #endif 1126 #endif /* INET */ 1127