1 /* $OpenBSD: if_ether.c,v 1.86 2010/05/07 13:33:16 claudio 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, u_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; 94 int la_hold_total; 95 96 /* revarp state */ 97 struct in_addr myip, srv_ip; 98 int myip_initialized; 99 int revarp_in_progress; 100 struct ifnet *myip_ifp; 101 102 #ifdef DDB 103 #include <uvm/uvm_extern.h> 104 105 void db_print_sa(struct sockaddr *); 106 void db_print_ifa(struct ifaddr *); 107 void db_print_llinfo(caddr_t); 108 int db_show_radix_node(struct radix_node *, void *); 109 #endif 110 111 /* 112 * Timeout routine. Age arp_tab entries periodically. 113 */ 114 /* ARGSUSED */ 115 void 116 arptimer(arg) 117 void *arg; 118 { 119 struct timeout *to = (struct timeout *)arg; 120 int s; 121 struct llinfo_arp *la, *nla; 122 123 s = splsoftnet(); 124 timeout_add_sec(to, arpt_prune); 125 for (la = LIST_FIRST(&llinfo_arp); la != LIST_END(&llinfo_arp); 126 la = nla) { 127 struct rtentry *rt = la->la_rt; 128 129 nla = LIST_NEXT(la, la_list); 130 if (rt->rt_expire && rt->rt_expire <= time_second) 131 arptfree(la); /* timer has expired; clear */ 132 } 133 splx(s); 134 } 135 136 /* 137 * Parallel to llc_rtrequest. 138 */ 139 void 140 arp_rtrequest(req, rt, info) 141 int req; 142 struct rtentry *rt; 143 struct rt_addrinfo *info; 144 { 145 struct sockaddr *gate = rt->rt_gateway; 146 struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo; 147 static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK}; 148 struct in_ifaddr *ia; 149 struct ifaddr *ifa; 150 struct mbuf *m; 151 152 if (!arpinit_done) { 153 static struct timeout arptimer_to; 154 155 arpinit_done = 1; 156 /* 157 * We generate expiration times from time.tv_sec 158 * so avoid accidently creating permanent routes. 159 */ 160 if (time_second == 0) { 161 time_second++; 162 } 163 164 timeout_set(&arptimer_to, arptimer, &arptimer_to); 165 timeout_add_sec(&arptimer_to, 1); 166 } 167 168 if (rt->rt_flags & RTF_GATEWAY) { 169 if (req != RTM_ADD) 170 return; 171 172 /* 173 * linklayers with particular link MTU limitation. it is a bit 174 * awkward to have FDDI handling here, we should split ARP from 175 * netinet/if_ether.c like NetBSD does. 176 */ 177 switch (rt->rt_ifp->if_type) { 178 case IFT_FDDI: 179 if (rt->rt_ifp->if_mtu > FDDIIPMTU) 180 rt->rt_rmx.rmx_mtu = FDDIIPMTU; 181 break; 182 } 183 184 return; 185 } 186 187 switch (req) { 188 189 case RTM_ADD: 190 /* 191 * XXX: If this is a manually added route to interface 192 * such as older version of routed or gated might provide, 193 * restore cloning bit. 194 */ 195 if ((rt->rt_flags & RTF_HOST) == 0 && 196 SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff) 197 rt->rt_flags |= RTF_CLONING; 198 if (rt->rt_flags & RTF_CLONING) { 199 /* 200 * Case 1: This route should come from a route to iface. 201 */ 202 rt_setgate(rt, rt_key(rt), 203 (struct sockaddr *)&null_sdl, 204 rt->rt_ifp->if_rdomain); 205 gate = rt->rt_gateway; 206 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 207 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 208 /* 209 * Give this route an expiration time, even though 210 * it's a "permanent" route, so that routes cloned 211 * from it do not need their expiration time set. 212 */ 213 rt->rt_expire = time_second; 214 /* 215 * linklayers with particular link MTU limitation. 216 */ 217 switch (rt->rt_ifp->if_type) { 218 case IFT_FDDI: 219 if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0 && 220 (rt->rt_rmx.rmx_mtu > FDDIIPMTU || 221 (rt->rt_rmx.rmx_mtu == 0 && 222 rt->rt_ifp->if_mtu > FDDIIPMTU))) 223 rt->rt_rmx.rmx_mtu = FDDIIPMTU; 224 break; 225 } 226 break; 227 } 228 /* Announce a new entry if requested. */ 229 if (rt->rt_flags & RTF_ANNOUNCE) 230 arprequest(rt->rt_ifp, 231 &SIN(rt_key(rt))->sin_addr.s_addr, 232 &SIN(rt_key(rt))->sin_addr.s_addr, 233 (u_char *)LLADDR(SDL(gate))); 234 /*FALLTHROUGH*/ 235 case RTM_RESOLVE: 236 if (gate->sa_family != AF_LINK || 237 gate->sa_len < sizeof(null_sdl)) { 238 log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n"); 239 break; 240 } 241 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 242 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 243 if (la != 0) 244 break; /* This happens on a route change */ 245 /* 246 * Case 2: This route may come from cloning, or a manual route 247 * add with a LL address. 248 */ 249 R_Malloc(la, struct llinfo_arp *, sizeof(*la)); 250 rt->rt_llinfo = (caddr_t)la; 251 if (la == 0) { 252 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); 253 break; 254 } 255 arp_inuse++, arp_allocated++; 256 Bzero(la, sizeof(*la)); 257 la->la_rt = rt; 258 rt->rt_flags |= RTF_LLINFO; 259 LIST_INSERT_HEAD(&llinfo_arp, la, la_list); 260 261 TAILQ_FOREACH(ia, &in_ifaddr, ia_list) { 262 if (ia->ia_ifp == rt->rt_ifp && 263 SIN(rt_key(rt))->sin_addr.s_addr == 264 (IA_SIN(ia))->sin_addr.s_addr) 265 break; 266 } 267 if (ia) { 268 /* 269 * This test used to be 270 * if (lo0ifp->if_flags & IFF_UP) 271 * It allowed local traffic to be forced through 272 * the hardware by configuring the loopback down. 273 * However, it causes problems during network 274 * configuration for boards that can't receive 275 * packets they send. It is now necessary to clear 276 * "useloopback" and remove the route to force 277 * traffic out to the hardware. 278 * 279 * In 4.4BSD, the above "if" statement checked 280 * rt->rt_ifa against rt_key(rt). It was changed 281 * to the current form so that we can provide a 282 * better support for multiple IPv4 addresses on a 283 * interface. 284 */ 285 rt->rt_expire = 0; 286 Bcopy(((struct arpcom *)rt->rt_ifp)->ac_enaddr, 287 LLADDR(SDL(gate)), 288 SDL(gate)->sdl_alen = ETHER_ADDR_LEN); 289 if (useloopback) 290 rt->rt_ifp = lo0ifp; 291 /* 292 * make sure to set rt->rt_ifa to the interface 293 * address we are using, otherwise we will have trouble 294 * with source address selection. 295 */ 296 ifa = &ia->ia_ifa; 297 if (ifa != rt->rt_ifa) { 298 IFAFREE(rt->rt_ifa); 299 ifa->ifa_refcnt++; 300 rt->rt_ifa = ifa; 301 } 302 } 303 break; 304 305 case RTM_DELETE: 306 if (la == 0) 307 break; 308 arp_inuse--; 309 LIST_REMOVE(la, la_list); 310 rt->rt_llinfo = 0; 311 rt->rt_flags &= ~RTF_LLINFO; 312 while ((m = la->la_hold_head) != NULL) { 313 la->la_hold_head = la->la_hold_head->m_nextpkt; 314 la_hold_total--; 315 m_freem(m); 316 } 317 Free((caddr_t)la); 318 } 319 } 320 321 /* 322 * Broadcast an ARP request. Caller specifies: 323 * - arp header source ip address 324 * - arp header target ip address 325 * - arp header source ethernet address 326 */ 327 void 328 arprequest(ifp, sip, tip, enaddr) 329 struct ifnet *ifp; 330 u_int32_t *sip, *tip; 331 u_int8_t *enaddr; 332 { 333 struct mbuf *m; 334 struct ether_header *eh; 335 struct ether_arp *ea; 336 struct sockaddr sa; 337 338 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 339 return; 340 m->m_len = sizeof(*ea); 341 m->m_pkthdr.len = sizeof(*ea); 342 m->m_pkthdr.rdomain = ifp->if_rdomain; 343 MH_ALIGN(m, sizeof(*ea)); 344 ea = mtod(m, struct ether_arp *); 345 eh = (struct ether_header *)sa.sa_data; 346 bzero((caddr_t)ea, sizeof (*ea)); 347 bcopy((caddr_t)etherbroadcastaddr, (caddr_t)eh->ether_dhost, 348 sizeof(eh->ether_dhost)); 349 eh->ether_type = htons(ETHERTYPE_ARP); /* if_output will not swap */ 350 ea->arp_hrd = htons(ARPHRD_ETHER); 351 ea->arp_pro = htons(ETHERTYPE_IP); 352 ea->arp_hln = sizeof(ea->arp_sha); /* hardware address length */ 353 ea->arp_pln = sizeof(ea->arp_spa); /* protocol address length */ 354 ea->arp_op = htons(ARPOP_REQUEST); 355 bcopy((caddr_t)enaddr, (caddr_t)eh->ether_shost, 356 sizeof(eh->ether_shost)); 357 bcopy((caddr_t)enaddr, (caddr_t)ea->arp_sha, sizeof(ea->arp_sha)); 358 bcopy((caddr_t)sip, (caddr_t)ea->arp_spa, sizeof(ea->arp_spa)); 359 bcopy((caddr_t)tip, (caddr_t)ea->arp_tpa, sizeof(ea->arp_tpa)); 360 sa.sa_family = pseudo_AF_HDRCMPLT; 361 sa.sa_len = sizeof(sa); 362 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 363 } 364 365 /* 366 * Resolve an IP address into an ethernet address. If success, 367 * desten is filled in. If there is no entry in arptab, 368 * set one up and broadcast a request for the IP address. 369 * Hold onto this mbuf and resend it once the address 370 * is finally resolved. A return value of 1 indicates 371 * that desten has been filled in and the packet should be sent 372 * normally; a 0 return indicates that the packet has been 373 * taken over here, either now or for later transmission. 374 */ 375 int 376 arpresolve(ac, rt, m, dst, desten) 377 struct arpcom *ac; 378 struct rtentry *rt; 379 struct mbuf *m; 380 struct sockaddr *dst; 381 u_char *desten; 382 { 383 struct llinfo_arp *la; 384 struct sockaddr_dl *sdl; 385 struct mbuf *mh; 386 387 if (m->m_flags & M_BCAST) { /* broadcast */ 388 bcopy((caddr_t)etherbroadcastaddr, (caddr_t)desten, 389 sizeof(etherbroadcastaddr)); 390 return (1); 391 } 392 if (m->m_flags & M_MCAST) { /* multicast */ 393 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); 394 return (1); 395 } 396 if (rt) { 397 la = (struct llinfo_arp *)rt->rt_llinfo; 398 if (la == NULL) 399 log(LOG_DEBUG, "arpresolve: %s: route without link " 400 "local address\n", inet_ntoa(SIN(dst)->sin_addr)); 401 } else { 402 if ((la = arplookup(SIN(dst)->sin_addr.s_addr, RT_REPORT, 0, 403 ac->ac_if.if_rdomain)) != NULL) 404 rt = la->la_rt; 405 else 406 log(LOG_DEBUG, 407 "arpresolve: %s: can't allocate llinfo\n", 408 inet_ntoa(SIN(dst)->sin_addr)); 409 } 410 if (la == 0 || rt == 0) { 411 m_freem(m); 412 return (0); 413 } 414 sdl = SDL(rt->rt_gateway); 415 /* 416 * Check the address family and length is valid, the address 417 * is resolved; otherwise, try to resolve. 418 */ 419 if ((rt->rt_expire == 0 || rt->rt_expire > time_second) && 420 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 421 bcopy(LLADDR(sdl), desten, sdl->sdl_alen); 422 return 1; 423 } 424 if (((struct ifnet *)ac)->if_flags & IFF_NOARP) { 425 m_freem(m); 426 return 0; 427 } 428 429 /* 430 * There is an arptab entry, but no ethernet address 431 * response yet. Insert mbuf in hold queue if below limit 432 * if above the limit free the queue without queuing the new packet. 433 */ 434 if (la_hold_total < MAX_HOLD_TOTAL && la_hold_total < nmbclust / 64) { 435 if (la->la_hold_count >= MAX_HOLD_QUEUE) { 436 mh = la->la_hold_head; 437 la->la_hold_head = la->la_hold_head->m_nextpkt; 438 if (mh == la->la_hold_tail) 439 la->la_hold_tail = NULL; 440 la->la_hold_count--; 441 la_hold_total--; 442 m_freem(mh); 443 } 444 if (la->la_hold_tail == NULL) 445 la->la_hold_head = m; 446 else 447 la->la_hold_tail->m_nextpkt = m; 448 la->la_hold_tail = m; 449 la->la_hold_count++; 450 la_hold_total++; 451 } else { 452 while ((mh = la->la_hold_head) != NULL) { 453 la->la_hold_head = 454 la->la_hold_head->m_nextpkt; 455 la_hold_total--; 456 m_freem(mh); 457 } 458 la->la_hold_tail = NULL; 459 la->la_hold_count = 0; 460 m_freem(m); 461 } 462 463 /* 464 * Re-send the ARP request when appropriate. 465 */ 466 #ifdef DIAGNOSTIC 467 if (rt->rt_expire == 0) { 468 /* This should never happen. (Should it? -gwr) */ 469 printf("arpresolve: unresolved and rt_expire == 0\n"); 470 /* Set expiration time to now (expired). */ 471 rt->rt_expire = time_second; 472 } 473 #endif 474 if (rt->rt_expire) { 475 rt->rt_flags &= ~RTF_REJECT; 476 if (la->la_asked == 0 || rt->rt_expire != time_second) { 477 rt->rt_expire = time_second; 478 if (la->la_asked++ < arp_maxtries) 479 arprequest(&ac->ac_if, 480 &(SIN(rt->rt_ifa->ifa_addr)->sin_addr.s_addr), 481 &(SIN(dst)->sin_addr.s_addr), 482 #if NCARP > 0 483 (rt->rt_ifp->if_type == IFT_CARP) ? 484 ((struct arpcom *) rt->rt_ifp->if_softc 485 )->ac_enaddr : 486 #endif 487 ac->ac_enaddr); 488 else { 489 rt->rt_flags |= RTF_REJECT; 490 rt->rt_expire += arpt_down; 491 la->la_asked = 0; 492 while ((mh = la->la_hold_head) != NULL) { 493 la->la_hold_head = 494 la->la_hold_head->m_nextpkt; 495 la_hold_total--; 496 m_freem(mh); 497 } 498 la->la_hold_tail = NULL; 499 la->la_hold_count = 0; 500 } 501 } 502 } 503 return (0); 504 } 505 506 /* 507 * Common length and type checks are done here, 508 * then the protocol-specific routine is called. 509 */ 510 void 511 arpintr() 512 { 513 struct mbuf *m; 514 struct arphdr *ar; 515 int s, len; 516 517 for (;;) { 518 s = splnet(); 519 IF_DEQUEUE(&arpintrq, m); 520 splx(s); 521 if (m == NULL) 522 break; 523 #ifdef DIAGNOSTIC 524 if ((m->m_flags & M_PKTHDR) == 0) 525 panic("arpintr"); 526 #endif 527 528 len = sizeof(struct arphdr); 529 if (m->m_len < len && (m = m_pullup(m, len)) == NULL) 530 continue; 531 532 ar = mtod(m, struct arphdr *); 533 if (ntohs(ar->ar_hrd) != ARPHRD_ETHER) { 534 m_freem(m); 535 continue; 536 } 537 538 len += 2 * (ar->ar_hln + ar->ar_pln); 539 if (m->m_len < len && (m = m_pullup(m, len)) == NULL) 540 continue; 541 542 switch (ntohs(ar->ar_pro)) { 543 case ETHERTYPE_IP: 544 case ETHERTYPE_IPTRAILERS: 545 in_arpinput(m); 546 continue; 547 } 548 m_freem(m); 549 } 550 } 551 552 /* 553 * ARP for Internet protocols on Ethernet. 554 * Algorithm is that given in RFC 826. 555 * In addition, a sanity check is performed on the sender 556 * protocol address, to catch impersonators. 557 * We no longer handle negotiations for use of trailer protocol: 558 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 559 * along with IP replies if we wanted trailers sent to us, 560 * and also sent them in response to IP replies. 561 * This allowed either end to announce the desire to receive 562 * trailer packets. 563 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 564 * but formerly didn't normally send requests. 565 */ 566 void 567 in_arpinput(m) 568 struct mbuf *m; 569 { 570 struct ether_arp *ea; 571 struct arpcom *ac = (struct arpcom *)m->m_pkthdr.rcvif; 572 struct ether_header *eh; 573 struct llinfo_arp *la = 0; 574 struct rtentry *rt; 575 struct in_ifaddr *ia; 576 struct sockaddr_dl *sdl; 577 struct sockaddr sa; 578 struct in_addr isaddr, itaddr, myaddr; 579 struct mbuf *mh, *mt; 580 u_int8_t *enaddr = NULL; 581 #if NCARP > 0 582 u_int8_t *ether_shost = NULL; 583 #endif 584 int op; 585 586 ea = mtod(m, struct ether_arp *); 587 op = ntohs(ea->arp_op); 588 if ((op != ARPOP_REQUEST) && (op != ARPOP_REPLY)) 589 goto out; 590 #if notyet 591 if ((op == ARPOP_REPLY) && (m->m_flags & (M_BCAST|M_MCAST))) { 592 log(LOG_ERR, 593 "arp: received reply to broadcast or multicast address\n"); 594 goto out; 595 } 596 #endif 597 598 bcopy((caddr_t)ea->arp_tpa, (caddr_t)&itaddr, sizeof(itaddr)); 599 bcopy((caddr_t)ea->arp_spa, (caddr_t)&isaddr, sizeof(isaddr)); 600 601 /* First try: check target against our addresses */ 602 TAILQ_FOREACH(ia, &in_ifaddr, ia_list) { 603 if (itaddr.s_addr != ia->ia_addr.sin_addr.s_addr) 604 continue; 605 606 #if NCARP > 0 607 if (ia->ia_ifp->if_type == IFT_CARP && 608 ((ia->ia_ifp->if_flags & (IFF_UP|IFF_RUNNING)) == 609 (IFF_UP|IFF_RUNNING))) { 610 if (ia->ia_ifp == m->m_pkthdr.rcvif) { 611 if (op == ARPOP_REPLY) 612 break; 613 if (carp_iamatch(ia, ea->arp_sha, 614 &enaddr, ðer_shost)) 615 break; 616 else 617 goto out; 618 } 619 } else 620 #endif 621 if (ia->ia_ifp == m->m_pkthdr.rcvif) 622 break; 623 } 624 625 /* Second try: check source against our addresses */ 626 if (ia == NULL) { 627 TAILQ_FOREACH(ia, &in_ifaddr, ia_list) { 628 if (isaddr.s_addr != ia->ia_addr.sin_addr.s_addr) 629 continue; 630 if (ia->ia_ifp == m->m_pkthdr.rcvif) 631 break; 632 } 633 } 634 635 /* Third try: not one of our addresses, just find an usable ia */ 636 if (ia == NULL) { 637 struct ifaddr *ifa; 638 639 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrlist, ifa_list) { 640 if (ifa->ifa_addr->sa_family == AF_INET) 641 break; 642 } 643 if (ifa) 644 ia = (struct in_ifaddr *)ifa; 645 } 646 647 if (ia == NULL) 648 goto out; 649 650 if (!enaddr) 651 enaddr = ac->ac_enaddr; 652 myaddr = ia->ia_addr.sin_addr; 653 654 if (!bcmp((caddr_t)ea->arp_sha, enaddr, sizeof (ea->arp_sha))) 655 goto out; /* it's from me, ignore it. */ 656 if (ETHER_IS_MULTICAST(&ea->arp_sha[0])) 657 if (!bcmp((caddr_t)ea->arp_sha, (caddr_t)etherbroadcastaddr, 658 sizeof (ea->arp_sha))) { 659 log(LOG_ERR, "arp: ether address is broadcast for " 660 "IP address %s!\n", inet_ntoa(isaddr)); 661 goto out; 662 } 663 if (myaddr.s_addr && isaddr.s_addr == myaddr.s_addr) { 664 log(LOG_ERR, 665 "duplicate IP address %s sent from ethernet address %s\n", 666 inet_ntoa(isaddr), ether_sprintf(ea->arp_sha)); 667 itaddr = myaddr; 668 goto reply; 669 } 670 la = arplookup(isaddr.s_addr, itaddr.s_addr == myaddr.s_addr, 0, 671 rtable_l2(m->m_pkthdr.rdomain)); 672 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { 673 if (sdl->sdl_alen) { 674 if (bcmp(ea->arp_sha, LLADDR(sdl), sdl->sdl_alen)) { 675 if (rt->rt_flags & RTF_PERMANENT_ARP) { 676 log(LOG_WARNING, 677 "arp: attempt to overwrite permanent " 678 "entry for %s by %s on %s\n", 679 inet_ntoa(isaddr), 680 ether_sprintf(ea->arp_sha), 681 ac->ac_if.if_xname); 682 goto out; 683 } else if (rt->rt_ifp != &ac->ac_if) { 684 if (ac->ac_if.if_type != IFT_CARP) 685 log(LOG_WARNING, 686 "arp: attempt to overwrite entry for" 687 " %s on %s by %s on %s\n", 688 inet_ntoa(isaddr), 689 rt->rt_ifp->if_xname, 690 ether_sprintf(ea->arp_sha), 691 ac->ac_if.if_xname); 692 goto out; 693 } else { 694 log(LOG_INFO, 695 "arp info overwritten for %s by %s on %s\n", 696 inet_ntoa(isaddr), 697 ether_sprintf(ea->arp_sha), 698 ac->ac_if.if_xname); 699 rt->rt_expire = 1; /* no longer static */ 700 } 701 } 702 } else if (rt->rt_ifp != &ac->ac_if && !(ac->ac_if.if_bridge && 703 (rt->rt_ifp->if_bridge == ac->ac_if.if_bridge)) && 704 !(rt->rt_ifp->if_type == IFT_CARP && 705 rt->rt_ifp->if_carpdev == &ac->ac_if) && 706 !(ac->ac_if.if_type == IFT_CARP && 707 ac->ac_if.if_carpdev == rt->rt_ifp)) { 708 log(LOG_WARNING, 709 "arp: attempt to add entry for %s " 710 "on %s by %s on %s\n", 711 inet_ntoa(isaddr), rt->rt_ifp->if_xname, 712 ether_sprintf(ea->arp_sha), 713 ac->ac_if.if_xname); 714 goto out; 715 } 716 bcopy(ea->arp_sha, LLADDR(sdl), 717 sdl->sdl_alen = sizeof(ea->arp_sha)); 718 if (rt->rt_expire) 719 rt->rt_expire = time_second + arpt_keep; 720 rt->rt_flags &= ~RTF_REJECT; 721 la->la_asked = 0; 722 while ((mh = la->la_hold_head) != NULL) { 723 if ((la->la_hold_head = mh->m_nextpkt) == NULL) 724 la->la_hold_tail = NULL; 725 la->la_hold_count--; 726 la_hold_total--; 727 mt = la->la_hold_tail; 728 729 (*ac->ac_if.if_output)(&ac->ac_if, mh, rt_key(rt), rt); 730 731 if (la->la_hold_tail == mh) { 732 /* mbuf is back in queue. Discard. */ 733 la->la_hold_tail = mt; 734 if (la->la_hold_tail) 735 la->la_hold_tail->m_nextpkt = NULL; 736 else 737 la->la_hold_head = NULL; 738 la->la_hold_count--; 739 la_hold_total--; 740 m_freem(mh); 741 } 742 } 743 } 744 reply: 745 if (op != ARPOP_REQUEST) { 746 out: 747 m_freem(m); 748 return; 749 } 750 if (itaddr.s_addr == myaddr.s_addr) { 751 /* I am the target */ 752 bcopy(ea->arp_sha, ea->arp_tha, sizeof(ea->arp_sha)); 753 bcopy(enaddr, ea->arp_sha, sizeof(ea->arp_sha)); 754 } else { 755 la = arplookup(itaddr.s_addr, 0, SIN_PROXY, 756 rtable_l2(m->m_pkthdr.rdomain)); 757 if (la == 0) 758 goto out; 759 rt = la->la_rt; 760 if (rt->rt_ifp->if_type == IFT_CARP && 761 m->m_pkthdr.rcvif->if_type != IFT_CARP) 762 goto out; 763 bcopy(ea->arp_sha, ea->arp_tha, sizeof(ea->arp_sha)); 764 sdl = SDL(rt->rt_gateway); 765 bcopy(LLADDR(sdl), ea->arp_sha, sizeof(ea->arp_sha)); 766 } 767 768 bcopy(ea->arp_spa, ea->arp_tpa, sizeof(ea->arp_spa)); 769 bcopy(&itaddr, ea->arp_spa, sizeof(ea->arp_spa)); 770 ea->arp_op = htons(ARPOP_REPLY); 771 ea->arp_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 772 eh = (struct ether_header *)sa.sa_data; 773 bcopy(ea->arp_tha, eh->ether_dhost, sizeof(eh->ether_dhost)); 774 #if NCARP > 0 775 if (ether_shost) 776 enaddr = ether_shost; 777 #endif 778 bcopy(enaddr, eh->ether_shost, sizeof(eh->ether_shost)); 779 780 eh->ether_type = htons(ETHERTYPE_ARP); 781 sa.sa_family = pseudo_AF_HDRCMPLT; 782 sa.sa_len = sizeof(sa); 783 (*ac->ac_if.if_output)(&ac->ac_if, m, &sa, (struct rtentry *)0); 784 return; 785 } 786 787 /* 788 * Free an arp entry. 789 */ 790 void 791 arptfree(la) 792 struct llinfo_arp *la; 793 { 794 struct rtentry *rt = la->la_rt; 795 struct sockaddr_dl *sdl; 796 struct rt_addrinfo info; 797 u_int tid = 0; 798 799 if (rt == 0) 800 panic("arptfree"); 801 if (rt->rt_refcnt > 0 && (sdl = SDL(rt->rt_gateway)) && 802 sdl->sdl_family == AF_LINK) { 803 sdl->sdl_alen = 0; 804 la->la_asked = 0; 805 rt->rt_flags &= ~RTF_REJECT; 806 return; 807 } 808 bzero(&info, sizeof(info)); 809 info.rti_info[RTAX_DST] = rt_key(rt); 810 info.rti_info[RTAX_NETMASK] = rt_mask(rt); 811 812 if (rt->rt_ifp) 813 tid = rt->rt_ifp->if_rdomain; 814 815 rtrequest1(RTM_DELETE, &info, rt->rt_priority, NULL, tid); 816 } 817 818 /* 819 * Lookup or enter a new address in arptab. 820 */ 821 struct llinfo_arp * 822 arplookup(addr, create, proxy, tableid) 823 u_int32_t addr; 824 int create, proxy; 825 u_int tableid; 826 { 827 struct rtentry *rt; 828 static struct sockaddr_inarp sin; 829 830 sin.sin_len = sizeof(sin); 831 sin.sin_family = AF_INET; 832 sin.sin_addr.s_addr = addr; 833 sin.sin_other = proxy ? SIN_PROXY : 0; 834 rt = rtalloc1(sintosa(&sin), create, tableid); 835 if (rt == 0) 836 return (0); 837 rt->rt_refcnt--; 838 if ((rt->rt_flags & RTF_GATEWAY) || (rt->rt_flags & RTF_LLINFO) == 0 || 839 rt->rt_gateway->sa_family != AF_LINK) { 840 if (create) { 841 if (rt->rt_refcnt <= 0 && 842 (rt->rt_flags & RTF_CLONED) != 0) { 843 struct rt_addrinfo info; 844 845 bzero(&info, sizeof(info)); 846 info.rti_info[RTAX_DST] = rt_key(rt); 847 info.rti_info[RTAX_GATEWAY] = rt->rt_gateway; 848 info.rti_info[RTAX_NETMASK] = rt_mask(rt); 849 850 rtrequest1(RTM_DELETE, &info, rt->rt_priority, 851 NULL, tableid); 852 } 853 } 854 return (0); 855 } 856 return ((struct llinfo_arp *)rt->rt_llinfo); 857 } 858 859 void 860 arp_ifinit(ac, ifa) 861 struct arpcom *ac; 862 struct ifaddr *ifa; 863 { 864 865 /* Warn the user if another station has this IP address. */ 866 arprequest(&ac->ac_if, 867 &(IA_SIN(ifa)->sin_addr.s_addr), 868 &(IA_SIN(ifa)->sin_addr.s_addr), 869 ac->ac_enaddr); 870 ifa->ifa_rtrequest = arp_rtrequest; 871 ifa->ifa_flags |= RTF_CLONING; 872 } 873 874 /* 875 * Called from Ethernet interrupt handlers 876 * when ether packet type ETHERTYPE_REVARP 877 * is received. Common length and type checks are done here, 878 * then the protocol-specific routine is called. 879 */ 880 void 881 revarpinput(m) 882 struct mbuf *m; 883 { 884 struct arphdr *ar; 885 886 if (m->m_len < sizeof(struct arphdr)) 887 goto out; 888 ar = mtod(m, struct arphdr *); 889 if (ntohs(ar->ar_hrd) != ARPHRD_ETHER) 890 goto out; 891 if (m->m_len < sizeof(struct arphdr) + 2 * (ar->ar_hln + ar->ar_pln)) 892 goto out; 893 switch (ntohs(ar->ar_pro)) { 894 895 case ETHERTYPE_IP: 896 case ETHERTYPE_IPTRAILERS: 897 in_revarpinput(m); 898 return; 899 900 default: 901 break; 902 } 903 out: 904 m_freem(m); 905 } 906 907 /* 908 * RARP for Internet protocols on Ethernet. 909 * Algorithm is that given in RFC 903. 910 * We are only using for bootstrap purposes to get an ip address for one of 911 * our interfaces. Thus we support no user-interface. 912 * 913 * Since the contents of the RARP reply are specific to the interface that 914 * sent the request, this code must ensure that they are properly associated. 915 * 916 * Note: also supports ARP via RARP packets, per the RFC. 917 */ 918 void 919 in_revarpinput(m) 920 struct mbuf *m; 921 { 922 struct ifnet *ifp; 923 struct ether_arp *ar; 924 int op; 925 926 ar = mtod(m, struct ether_arp *); 927 op = ntohs(ar->arp_op); 928 switch (op) { 929 case ARPOP_REQUEST: 930 case ARPOP_REPLY: /* per RFC */ 931 in_arpinput(m); 932 return; 933 case ARPOP_REVREPLY: 934 break; 935 case ARPOP_REVREQUEST: /* handled by rarpd(8) */ 936 default: 937 goto out; 938 } 939 if (!revarp_in_progress) 940 goto out; 941 ifp = m->m_pkthdr.rcvif; 942 if (ifp != myip_ifp) /* !same interface */ 943 goto out; 944 if (myip_initialized) 945 goto wake; 946 if (bcmp(ar->arp_tha, ((struct arpcom *)ifp)->ac_enaddr, 947 sizeof(ar->arp_tha))) 948 goto out; 949 bcopy((caddr_t)ar->arp_spa, (caddr_t)&srv_ip, sizeof(srv_ip)); 950 bcopy((caddr_t)ar->arp_tpa, (caddr_t)&myip, sizeof(myip)); 951 myip_initialized = 1; 952 wake: /* Do wakeup every time in case it was missed. */ 953 wakeup((caddr_t)&myip); 954 955 out: 956 m_freem(m); 957 } 958 959 /* 960 * Send a RARP request for the ip address of the specified interface. 961 * The request should be RFC 903-compliant. 962 */ 963 void 964 revarprequest(ifp) 965 struct ifnet *ifp; 966 { 967 struct sockaddr sa; 968 struct mbuf *m; 969 struct ether_header *eh; 970 struct ether_arp *ea; 971 struct arpcom *ac = (struct arpcom *)ifp; 972 973 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 974 return; 975 m->m_len = sizeof(*ea); 976 m->m_pkthdr.len = sizeof(*ea); 977 MH_ALIGN(m, sizeof(*ea)); 978 ea = mtod(m, struct ether_arp *); 979 eh = (struct ether_header *)sa.sa_data; 980 bzero((caddr_t)ea, sizeof(*ea)); 981 bcopy((caddr_t)etherbroadcastaddr, (caddr_t)eh->ether_dhost, 982 sizeof(eh->ether_dhost)); 983 eh->ether_type = htons(ETHERTYPE_REVARP); 984 ea->arp_hrd = htons(ARPHRD_ETHER); 985 ea->arp_pro = htons(ETHERTYPE_IP); 986 ea->arp_hln = sizeof(ea->arp_sha); /* hardware address length */ 987 ea->arp_pln = sizeof(ea->arp_spa); /* protocol address length */ 988 ea->arp_op = htons(ARPOP_REVREQUEST); 989 bcopy((caddr_t)ac->ac_enaddr, (caddr_t)eh->ether_shost, 990 sizeof(ea->arp_tha)); 991 bcopy((caddr_t)ac->ac_enaddr, (caddr_t)ea->arp_sha, 992 sizeof(ea->arp_sha)); 993 bcopy((caddr_t)ac->ac_enaddr, (caddr_t)ea->arp_tha, 994 sizeof(ea->arp_tha)); 995 sa.sa_family = pseudo_AF_HDRCMPLT; 996 sa.sa_len = sizeof(sa); 997 ifp->if_output(ifp, m, &sa, (struct rtentry *)0); 998 } 999 1000 /* 1001 * RARP for the ip address of the specified interface, but also 1002 * save the ip address of the server that sent the answer. 1003 * Timeout if no response is received. 1004 */ 1005 int 1006 revarpwhoarewe(ifp, serv_in, clnt_in) 1007 struct ifnet *ifp; 1008 struct in_addr *serv_in; 1009 struct in_addr *clnt_in; 1010 { 1011 int result, count = 20; 1012 1013 if (myip_initialized) 1014 return EIO; 1015 1016 myip_ifp = ifp; 1017 revarp_in_progress = 1; 1018 while (count--) { 1019 revarprequest(ifp); 1020 result = tsleep((caddr_t)&myip, PSOCK, "revarp", hz/2); 1021 if (result != EWOULDBLOCK) 1022 break; 1023 } 1024 revarp_in_progress = 0; 1025 if (!myip_initialized) 1026 return ENETUNREACH; 1027 1028 bcopy((caddr_t)&srv_ip, serv_in, sizeof(*serv_in)); 1029 bcopy((caddr_t)&myip, clnt_in, sizeof(*clnt_in)); 1030 return 0; 1031 } 1032 1033 /* For compatibility: only saves interface address. */ 1034 int 1035 revarpwhoami(in, ifp) 1036 struct in_addr *in; 1037 struct ifnet *ifp; 1038 { 1039 struct in_addr server; 1040 return (revarpwhoarewe(ifp, &server, in)); 1041 } 1042 1043 1044 #ifdef DDB 1045 1046 #include <machine/db_machdep.h> 1047 #include <ddb/db_interface.h> 1048 #include <ddb/db_output.h> 1049 1050 void 1051 db_print_sa(sa) 1052 struct sockaddr *sa; 1053 { 1054 int len; 1055 u_char *p; 1056 1057 if (sa == 0) { 1058 db_printf("[NULL]"); 1059 return; 1060 } 1061 1062 p = (u_char *)sa; 1063 len = sa->sa_len; 1064 db_printf("["); 1065 while (len > 0) { 1066 db_printf("%d", *p); 1067 p++; 1068 len--; 1069 if (len) 1070 db_printf(","); 1071 } 1072 db_printf("]\n"); 1073 } 1074 1075 void 1076 db_print_ifa(ifa) 1077 struct ifaddr *ifa; 1078 { 1079 if (ifa == 0) 1080 return; 1081 db_printf(" ifa_addr="); 1082 db_print_sa(ifa->ifa_addr); 1083 db_printf(" ifa_dsta="); 1084 db_print_sa(ifa->ifa_dstaddr); 1085 db_printf(" ifa_mask="); 1086 db_print_sa(ifa->ifa_netmask); 1087 db_printf(" flags=0x%x, refcnt=%d, metric=%d\n", 1088 ifa->ifa_flags, ifa->ifa_refcnt, ifa->ifa_metric); 1089 } 1090 1091 void 1092 db_print_llinfo(li) 1093 caddr_t li; 1094 { 1095 struct llinfo_arp *la; 1096 1097 if (li == 0) 1098 return; 1099 la = (struct llinfo_arp *)li; 1100 db_printf(" la_rt=%p la_hold_head=%p, la_asked=0x%lx\n", 1101 la->la_rt, la->la_hold_head, la->la_asked); 1102 } 1103 1104 /* 1105 * Function to pass to rn_walktree(). 1106 * Return non-zero error to abort walk. 1107 */ 1108 int 1109 db_show_radix_node(rn, w) 1110 struct radix_node *rn; 1111 void *w; 1112 { 1113 struct rtentry *rt = (struct rtentry *)rn; 1114 1115 db_printf("rtentry=%p", rt); 1116 1117 db_printf(" flags=0x%x refcnt=%d use=%ld expire=%ld\n", 1118 rt->rt_flags, rt->rt_refcnt, rt->rt_use, rt->rt_expire); 1119 1120 db_printf(" key="); db_print_sa(rt_key(rt)); 1121 db_printf(" mask="); db_print_sa(rt_mask(rt)); 1122 db_printf(" gw="); db_print_sa(rt->rt_gateway); 1123 1124 db_printf(" ifp=%p ", rt->rt_ifp); 1125 if (rt->rt_ifp) 1126 db_printf("(%s)", rt->rt_ifp->if_xname); 1127 else 1128 db_printf("(NULL)"); 1129 1130 db_printf(" ifa=%p\n", rt->rt_ifa); 1131 db_print_ifa(rt->rt_ifa); 1132 1133 db_printf(" genmask="); db_print_sa(rt->rt_genmask); 1134 1135 db_printf(" gwroute=%p llinfo=%p\n", rt->rt_gwroute, rt->rt_llinfo); 1136 db_print_llinfo(rt->rt_llinfo); 1137 return (0); 1138 } 1139 1140 /* 1141 * Function to print all the route trees. 1142 * Use this from ddb: "call db_show_arptab" 1143 */ 1144 int 1145 db_show_arptab() 1146 { 1147 struct radix_node_head *rnh; 1148 rnh = rt_gettable(AF_INET, 0); 1149 db_printf("Route tree for AF_INET\n"); 1150 if (rnh == NULL) { 1151 db_printf(" (not initialized)\n"); 1152 return (0); 1153 } 1154 rn_walktree(rnh, db_show_radix_node, NULL); 1155 return (0); 1156 } 1157 #endif 1158 #endif /* INET */ 1159