1/* $OpenBSD: if_ether.c,v 1.267 2023/12/18 13:30:44 bluhm 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#include "carp.h" 42 43#include <sys/param.h> 44#include <sys/systm.h> 45#include <sys/mbuf.h> 46#include <sys/socket.h> 47#include <sys/timeout.h> 48#include <sys/kernel.h> 49#include <sys/syslog.h> 50#include <sys/queue.h> 51#include <sys/pool.h> 52 53#include <net/if.h> 54#include <net/if_var.h> 55#include <net/if_dl.h> 56#include <net/route.h> 57#include <net/if_types.h> 58#include <net/netisr.h> 59 60#include <netinet/in.h> 61#include <netinet/in_var.h> 62#include <netinet/if_ether.h> 63#include <netinet/ip_var.h> 64#if NCARP > 0 65#include <netinet/ip_carp.h> 66#endif 67 68/* 69 * Locks used to protect struct members in this file: 70 * a atomic operations 71 * I immutable after creation 72 * K kernel lock 73 * m arp mutex, needed when net lock is shared 74 * N net lock 75 */ 76 77struct llinfo_arp { 78 LIST_ENTRY(llinfo_arp) la_list; /* [mN] global arp_list */ 79 struct rtentry *la_rt; /* [I] backpointer to rtentry */ 80 struct mbuf_queue la_mq; /* packet hold queue */ 81 time_t la_refreshed; /* when was refresh sent */ 82 int la_asked; /* number of queries sent */ 83}; 84#define LA_HOLD_QUEUE 10 85#define LA_HOLD_TOTAL 100 86 87/* timer values */ 88int arpt_prune = (5 * 60); /* [I] walk list every 5 minutes */ 89int arpt_keep = (20 * 60); /* [a] once resolved, cache for 20 minutes */ 90int arpt_down = 20; /* [a] once declared down, don't send for 20 secs */ 91 92struct mbuf *arppullup(struct mbuf *m); 93void arpinvalidate(struct rtentry *); 94void arptfree(struct rtentry *); 95void arptimer(void *); 96struct rtentry *arplookup(struct in_addr *, int, int, unsigned int); 97void in_arpinput(struct ifnet *, struct mbuf *); 98void in_revarpinput(struct ifnet *, struct mbuf *); 99int arpcache(struct ifnet *, struct ether_arp *, struct rtentry *); 100void arpreply(struct ifnet *, struct mbuf *, struct in_addr *, uint8_t *, 101 unsigned int); 102 103struct niqueue arpinq = NIQUEUE_INITIALIZER(50, NETISR_ARP); 104 105/* llinfo_arp live time, rt_llinfo and RTF_LLINFO are protected by arp_mtx */ 106struct mutex arp_mtx = MUTEX_INITIALIZER(IPL_SOFTNET); 107 108LIST_HEAD(, llinfo_arp) arp_list = 109 LIST_HEAD_INITIALIZER(arp_list); /* [mN] list of llinfo_arp structures */ 110struct pool arp_pool; /* [I] pool for llinfo_arp structures */ 111int arp_maxtries = 5; /* [I] arp requests before set to rejected */ 112unsigned int la_hold_total; /* [a] packets currently in the arp queue */ 113 114#ifdef NFSCLIENT 115/* revarp state */ 116struct in_addr revarp_myip, revarp_srvip; 117int revarp_finished; 118unsigned int revarp_ifidx; 119#endif /* NFSCLIENT */ 120 121/* 122 * Timeout routine. Age arp_tab entries periodically. 123 */ 124void 125arptimer(void *arg) 126{ 127 struct timeout *to = arg; 128 struct llinfo_arp *la, *nla; 129 time_t uptime; 130 131 NET_LOCK(); 132 uptime = getuptime(); 133 timeout_add_sec(to, arpt_prune); 134 /* Net lock is exclusive, no arp mutex needed for arp_list here. */ 135 LIST_FOREACH_SAFE(la, &arp_list, la_list, nla) { 136 struct rtentry *rt = la->la_rt; 137 138 if (rt->rt_expire && rt->rt_expire < uptime) 139 arptfree(rt); /* timer has expired; clear */ 140 } 141 NET_UNLOCK(); 142} 143 144void 145arpinit(void) 146{ 147 static struct timeout arptimer_to; 148 149 pool_init(&arp_pool, sizeof(struct llinfo_arp), 0, 150 IPL_SOFTNET, 0, "arp", NULL); 151 152 timeout_set_flags(&arptimer_to, arptimer, &arptimer_to, 153 KCLOCK_NONE, TIMEOUT_PROC | TIMEOUT_MPSAFE); 154 timeout_add_sec(&arptimer_to, arpt_prune); 155} 156 157void 158arp_rtrequest(struct ifnet *ifp, int req, struct rtentry *rt) 159{ 160 struct sockaddr *gate = rt->rt_gateway; 161 struct llinfo_arp *la; 162 time_t uptime; 163 164 NET_ASSERT_LOCKED(); 165 166 if (ISSET(rt->rt_flags, 167 RTF_GATEWAY|RTF_BROADCAST|RTF_MULTICAST|RTF_MPLS)) 168 return; 169 170 uptime = getuptime(); 171 switch (req) { 172 case RTM_ADD: 173 if (rt->rt_flags & RTF_CLONING) { 174 rt->rt_expire = 0; 175 break; 176 } 177 if ((rt->rt_flags & RTF_LOCAL) && rt->rt_llinfo == NULL) 178 rt->rt_expire = 0; 179 /* 180 * Announce a new entry if requested or warn the user 181 * if another station has this IP address. 182 */ 183 if (rt->rt_flags & (RTF_ANNOUNCE|RTF_LOCAL)) 184 arprequest(ifp, 185 &satosin(rt_key(rt))->sin_addr.s_addr, 186 &satosin(rt_key(rt))->sin_addr.s_addr, 187 (u_char *)LLADDR(satosdl(gate))); 188 /*FALLTHROUGH*/ 189 case RTM_RESOLVE: 190 if (gate->sa_family != AF_LINK || 191 gate->sa_len < sizeof(struct sockaddr_dl)) { 192 log(LOG_DEBUG, "%s: bad gateway value: %s\n", __func__, 193 ifp->if_xname); 194 break; 195 } 196 satosdl(gate)->sdl_type = ifp->if_type; 197 satosdl(gate)->sdl_index = ifp->if_index; 198 /* 199 * Case 2: This route may come from cloning, or a manual route 200 * add with a LL address. 201 */ 202 la = pool_get(&arp_pool, PR_NOWAIT | PR_ZERO); 203 if (la == NULL) { 204 log(LOG_DEBUG, "%s: pool get failed\n", __func__); 205 break; 206 } 207 208 mtx_enter(&arp_mtx); 209 if (rt->rt_llinfo != NULL) { 210 /* we lost the race, another thread has entered it */ 211 mtx_leave(&arp_mtx); 212 pool_put(&arp_pool, la); 213 break; 214 } 215 mq_init(&la->la_mq, LA_HOLD_QUEUE, IPL_SOFTNET); 216 rt->rt_llinfo = (caddr_t)la; 217 la->la_rt = rt; 218 rt->rt_flags |= RTF_LLINFO; 219 LIST_INSERT_HEAD(&arp_list, la, la_list); 220 if ((rt->rt_flags & RTF_LOCAL) == 0) 221 rt->rt_expire = uptime; 222 mtx_leave(&arp_mtx); 223 224 break; 225 226 case RTM_DELETE: 227 mtx_enter(&arp_mtx); 228 la = (struct llinfo_arp *)rt->rt_llinfo; 229 if (la == NULL) { 230 /* we lost the race, another thread has removed it */ 231 mtx_leave(&arp_mtx); 232 break; 233 } 234 LIST_REMOVE(la, la_list); 235 rt->rt_llinfo = NULL; 236 rt->rt_flags &= ~RTF_LLINFO; 237 atomic_sub_int(&la_hold_total, mq_purge(&la->la_mq)); 238 mtx_leave(&arp_mtx); 239 240 pool_put(&arp_pool, la); 241 break; 242 243 case RTM_INVALIDATE: 244 if (!ISSET(rt->rt_flags, RTF_LOCAL)) 245 arpinvalidate(rt); 246 break; 247 } 248} 249 250/* 251 * Broadcast an ARP request. Caller specifies: 252 * - arp header source ip address 253 * - arp header target ip address 254 * - arp header source ethernet address 255 */ 256void 257arprequest(struct ifnet *ifp, u_int32_t *sip, u_int32_t *tip, u_int8_t *enaddr) 258{ 259 struct mbuf *m; 260 struct ether_header *eh; 261 struct ether_arp *ea; 262 struct sockaddr sa; 263 264 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 265 return; 266 m->m_len = sizeof(*ea); 267 m->m_pkthdr.len = sizeof(*ea); 268 m->m_pkthdr.ph_rtableid = ifp->if_rdomain; 269 m->m_pkthdr.pf.prio = ifp->if_llprio; 270 m_align(m, sizeof(*ea)); 271 ea = mtod(m, struct ether_arp *); 272 eh = (struct ether_header *)sa.sa_data; 273 memset(ea, 0, sizeof(*ea)); 274 memcpy(eh->ether_dhost, etherbroadcastaddr, sizeof(eh->ether_dhost)); 275 eh->ether_type = htons(ETHERTYPE_ARP); /* if_output will not swap */ 276 ea->arp_hrd = htons(ARPHRD_ETHER); 277 ea->arp_pro = htons(ETHERTYPE_IP); 278 ea->arp_hln = sizeof(ea->arp_sha); /* hardware address length */ 279 ea->arp_pln = sizeof(ea->arp_spa); /* protocol address length */ 280 ea->arp_op = htons(ARPOP_REQUEST); 281 memcpy(eh->ether_shost, enaddr, sizeof(eh->ether_shost)); 282 memcpy(ea->arp_sha, enaddr, sizeof(ea->arp_sha)); 283 memcpy(ea->arp_spa, sip, sizeof(ea->arp_spa)); 284 memcpy(ea->arp_tpa, tip, sizeof(ea->arp_tpa)); 285 sa.sa_family = pseudo_AF_HDRCMPLT; 286 sa.sa_len = sizeof(sa); 287 m->m_flags |= M_BCAST; 288 ifp->if_output(ifp, m, &sa, NULL); 289} 290 291void 292arpreply(struct ifnet *ifp, struct mbuf *m, struct in_addr *sip, uint8_t *eaddr, 293 unsigned int rdomain) 294{ 295 struct ether_header *eh; 296 struct ether_arp *ea; 297 struct sockaddr sa; 298 299 m_resethdr(m); 300 m->m_pkthdr.ph_rtableid = rdomain; 301 302 ea = mtod(m, struct ether_arp *); 303 ea->arp_op = htons(ARPOP_REPLY); 304 ea->arp_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 305 306 /* We're replying to a request. */ 307 memcpy(ea->arp_tha, ea->arp_sha, sizeof(ea->arp_sha)); 308 memcpy(ea->arp_tpa, ea->arp_spa, sizeof(ea->arp_spa)); 309 310 memcpy(ea->arp_sha, eaddr, sizeof(ea->arp_sha)); 311 memcpy(ea->arp_spa, sip, sizeof(ea->arp_spa)); 312 313 eh = (struct ether_header *)sa.sa_data; 314 memcpy(eh->ether_dhost, ea->arp_tha, sizeof(eh->ether_dhost)); 315 memcpy(eh->ether_shost, eaddr, sizeof(eh->ether_shost)); 316 eh->ether_type = htons(ETHERTYPE_ARP); 317 sa.sa_family = pseudo_AF_HDRCMPLT; 318 sa.sa_len = sizeof(sa); 319 ifp->if_output(ifp, m, &sa, NULL); 320} 321 322/* 323 * Resolve an IP address into an ethernet address. If success, 324 * desten is filled in. If there is no entry in arptab, 325 * set one up and broadcast a request for the IP address. 326 * Hold onto this mbuf and resend it once the address 327 * is finally resolved. A return value of 0 indicates 328 * that desten has been filled in and the packet should be sent 329 * normally; A return value of EAGAIN indicates that the packet 330 * has been taken over here, either now or for later transmission. 331 * Any other return value indicates an error. 332 */ 333int 334arpresolve(struct ifnet *ifp, struct rtentry *rt0, struct mbuf *m, 335 struct sockaddr *dst, u_char *desten) 336{ 337 struct arpcom *ac = (struct arpcom *)ifp; 338 struct llinfo_arp *la; 339 struct sockaddr_dl *sdl; 340 struct rtentry *rt = NULL; 341 char addr[INET_ADDRSTRLEN]; 342 time_t uptime; 343 int refresh = 0, reject = 0; 344 345 if (m->m_flags & M_BCAST) { /* broadcast */ 346 memcpy(desten, etherbroadcastaddr, sizeof(etherbroadcastaddr)); 347 return (0); 348 } 349 if (m->m_flags & M_MCAST) { /* multicast */ 350 ETHER_MAP_IP_MULTICAST(&satosin(dst)->sin_addr, desten); 351 return (0); 352 } 353 354 uptime = getuptime(); 355 rt = rt_getll(rt0); 356 357 if (ISSET(rt->rt_flags, RTF_REJECT) && 358 (rt->rt_expire == 0 || rt->rt_expire > uptime)) { 359 m_freem(m); 360 return (rt == rt0 ? EHOSTDOWN : EHOSTUNREACH); 361 } 362 363 if (!ISSET(rt->rt_flags, RTF_LLINFO)) { 364 log(LOG_DEBUG, "%s: %s: route contains no arp information\n", 365 __func__, inet_ntop(AF_INET, &satosin(rt_key(rt))->sin_addr, 366 addr, sizeof(addr))); 367 goto bad; 368 } 369 370 sdl = satosdl(rt->rt_gateway); 371 if (sdl->sdl_alen > 0 && sdl->sdl_alen != ETHER_ADDR_LEN) { 372 log(LOG_DEBUG, "%s: %s: incorrect arp information\n", __func__, 373 inet_ntop(AF_INET, &satosin(dst)->sin_addr, 374 addr, sizeof(addr))); 375 goto bad; 376 } 377 378 379 /* 380 * Check the address family and length is valid, the address 381 * is resolved; otherwise, try to resolve. 382 */ 383 if ((rt->rt_expire == 0 || rt->rt_expire > uptime) && 384 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 385 memcpy(desten, LLADDR(sdl), sdl->sdl_alen); 386 387 /* refresh ARP entry when timeout gets close */ 388 if (rt->rt_expire != 0 && 389 rt->rt_expire - arpt_keep / 8 < uptime) { 390 391 mtx_enter(&arp_mtx); 392 la = (struct llinfo_arp *)rt->rt_llinfo; 393 if (la != NULL) { 394 if (la->la_refreshed + 30 < uptime) { 395 la->la_refreshed = uptime; 396 refresh = 1; 397 } 398 } 399 mtx_leave(&arp_mtx); 400 } 401 if (refresh) { 402 arprequest(ifp, 403 &satosin(rt->rt_ifa->ifa_addr)->sin_addr.s_addr, 404 &satosin(dst)->sin_addr.s_addr, 405 ac->ac_enaddr); 406 } 407 return (0); 408 } 409 410 if (ifp->if_flags & (IFF_NOARP|IFF_STATICARP)) 411 goto bad; 412 413 mtx_enter(&arp_mtx); 414 la = (struct llinfo_arp *)rt->rt_llinfo; 415 if (la == NULL) { 416 mtx_leave(&arp_mtx); 417 goto bad; 418 } 419 420 /* 421 * There is an arptab entry, but no ethernet address 422 * response yet. Insert mbuf in hold queue if below limit. 423 * If above the limit free the queue without queuing the new packet. 424 */ 425 if (atomic_inc_int_nv(&la_hold_total) <= LA_HOLD_TOTAL) { 426 if (mq_push(&la->la_mq, m) != 0) 427 atomic_dec_int(&la_hold_total); 428 } else { 429 atomic_sub_int(&la_hold_total, mq_purge(&la->la_mq) + 1); 430 m_freem(m); 431 } 432 433 /* 434 * Re-send the ARP request when appropriate. 435 */ 436#ifdef DIAGNOSTIC 437 if (rt->rt_expire == 0) { 438 /* This should never happen. (Should it? -gwr) */ 439 printf("%s: unresolved and rt_expire == 0\n", __func__); 440 /* Set expiration time to now (expired). */ 441 rt->rt_expire = uptime; 442 } 443#endif 444 if (rt->rt_expire) { 445 reject = ~RTF_REJECT; 446 if (la->la_asked == 0 || rt->rt_expire != uptime) { 447 rt->rt_expire = uptime; 448 if (la->la_asked++ < arp_maxtries) 449 refresh = 1; 450 else { 451 reject = RTF_REJECT; 452 rt->rt_expire += arpt_down; 453 la->la_asked = 0; 454 la->la_refreshed = 0; 455 atomic_sub_int(&la_hold_total, 456 mq_purge(&la->la_mq)); 457 } 458 } 459 } 460 mtx_leave(&arp_mtx); 461 462 if (reject == RTF_REJECT && !ISSET(rt->rt_flags, RTF_REJECT)) { 463 KERNEL_LOCK(); 464 SET(rt->rt_flags, RTF_REJECT); 465 KERNEL_UNLOCK(); 466 } 467 if (reject == ~RTF_REJECT && ISSET(rt->rt_flags, RTF_REJECT)) { 468 KERNEL_LOCK(); 469 CLR(rt->rt_flags, RTF_REJECT); 470 KERNEL_UNLOCK(); 471 } 472 if (refresh) 473 arprequest(ifp, &satosin(rt->rt_ifa->ifa_addr)->sin_addr.s_addr, 474 &satosin(dst)->sin_addr.s_addr, ac->ac_enaddr); 475 return (EAGAIN); 476 477bad: 478 m_freem(m); 479 return (EINVAL); 480} 481 482struct mbuf * 483arppullup(struct mbuf *m) 484{ 485 struct arphdr *ar; 486 int len; 487 488#ifdef DIAGNOSTIC 489 if ((m->m_flags & M_PKTHDR) == 0) 490 panic("arp without packet header"); 491#endif 492 493 len = sizeof(struct arphdr); 494 if (m->m_len < len && (m = m_pullup(m, len)) == NULL) 495 return NULL; 496 497 ar = mtod(m, struct arphdr *); 498 if (ntohs(ar->ar_hrd) != ARPHRD_ETHER || 499 ntohs(ar->ar_pro) != ETHERTYPE_IP || 500 ar->ar_hln != ETHER_ADDR_LEN || 501 ar->ar_pln != sizeof(struct in_addr)) { 502 m_freem(m); 503 return NULL; 504 } 505 506 len += 2 * (ar->ar_hln + ar->ar_pln); 507 if (m->m_len < len && (m = m_pullup(m, len)) == NULL) 508 return NULL; 509 510 return m; 511} 512 513/* 514 * Common length and type checks are done here, 515 * then the protocol-specific routine is called. 516 */ 517void 518arpinput(struct ifnet *ifp, struct mbuf *m) 519{ 520 if ((m = arppullup(m)) == NULL) 521 return; 522 niq_enqueue(&arpinq, m); 523} 524 525void 526arpintr(void) 527{ 528 struct mbuf_list ml; 529 struct mbuf *m; 530 struct ifnet *ifp; 531 532 niq_delist(&arpinq, &ml); 533 534 while ((m = ml_dequeue(&ml)) != NULL) { 535 ifp = if_get(m->m_pkthdr.ph_ifidx); 536 537 if (ifp != NULL) 538 in_arpinput(ifp, m); 539 else 540 m_freem(m); 541 542 if_put(ifp); 543 } 544} 545 546/* 547 * ARP for Internet protocols on Ethernet, RFC 826. 548 * In addition, a sanity check is performed on the sender 549 * protocol address, to catch impersonators. 550 */ 551void 552in_arpinput(struct ifnet *ifp, struct mbuf *m) 553{ 554 struct ether_arp *ea; 555 struct rtentry *rt = NULL; 556 struct sockaddr_in sin; 557 struct in_addr isaddr, itaddr; 558 char addr[INET_ADDRSTRLEN]; 559 int op, target = 0; 560 unsigned int rdomain; 561 562 rdomain = rtable_l2(m->m_pkthdr.ph_rtableid); 563 564 ea = mtod(m, struct ether_arp *); 565 op = ntohs(ea->arp_op); 566 if ((op != ARPOP_REQUEST) && (op != ARPOP_REPLY)) 567 goto out; 568 569 memcpy(&itaddr, ea->arp_tpa, sizeof(itaddr)); 570 memcpy(&isaddr, ea->arp_spa, sizeof(isaddr)); 571 memset(&sin, 0, sizeof(sin)); 572 sin.sin_len = sizeof(sin); 573 sin.sin_family = AF_INET; 574 575 if (ETHER_IS_MULTICAST(ea->arp_sha) && 576 ETHER_IS_BROADCAST(ea->arp_sha)) { 577 inet_ntop(AF_INET, &isaddr, addr, sizeof(addr)); 578 log(LOG_ERR, "arp: ether address is broadcast for IP address " 579 "%s!\n", addr); 580 goto out; 581 } 582 583 if (!memcmp(ea->arp_sha, LLADDR(ifp->if_sadl), sizeof(ea->arp_sha))) 584 goto out; /* it's from me, ignore it. */ 585 586 /* Check target against our interface addresses. */ 587 sin.sin_addr = itaddr; 588 rt = rtalloc(sintosa(&sin), 0, rdomain); 589 if (rtisvalid(rt) && ISSET(rt->rt_flags, RTF_LOCAL) && 590 rt->rt_ifidx == ifp->if_index) 591 target = 1; 592 rtfree(rt); 593 rt = NULL; 594 595#if NCARP > 0 596 if (target && op == ARPOP_REQUEST && ifp->if_type == IFT_CARP && 597 !carp_iamatch(ifp)) 598 goto out; 599#endif 600 601 /* Do we have an ARP cache for the sender? Create if we are target. */ 602 rt = arplookup(&isaddr, target, 0, rdomain); 603 604 /* Check sender against our interface addresses. */ 605 if (rtisvalid(rt) && ISSET(rt->rt_flags, RTF_LOCAL) && 606 rt->rt_ifidx == ifp->if_index && isaddr.s_addr != INADDR_ANY) { 607 inet_ntop(AF_INET, &isaddr, addr, sizeof(addr)); 608 log(LOG_ERR, "duplicate IP address %s sent from ethernet " 609 "address %s\n", addr, ether_sprintf(ea->arp_sha)); 610 itaddr = isaddr; 611 } else if (rt != NULL) { 612 if (arpcache(ifp, ea, rt)) 613 goto out; 614 } 615 616 if (op == ARPOP_REQUEST) { 617 uint8_t *eaddr; 618 619 if (target) { 620 /* We already have all info for the reply */ 621 eaddr = LLADDR(ifp->if_sadl); 622 } else { 623 rtfree(rt); 624 rt = arplookup(&itaddr, 0, SIN_PROXY, rdomain); 625 /* 626 * Protect from possible duplicates, only owner 627 * should respond 628 */ 629 if ((rt == NULL) || (rt->rt_ifidx != ifp->if_index)) 630 goto out; 631 eaddr = LLADDR(satosdl(rt->rt_gateway)); 632 } 633 arpreply(ifp, m, &itaddr, eaddr, rdomain); 634 rtfree(rt); 635 return; 636 } 637 638out: 639 rtfree(rt); 640 m_freem(m); 641} 642 643int 644arpcache(struct ifnet *ifp, struct ether_arp *ea, struct rtentry *rt) 645{ 646 struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo; 647 struct sockaddr_dl *sdl = satosdl(rt->rt_gateway); 648 struct in_addr *spa = (struct in_addr *)ea->arp_spa; 649 char addr[INET_ADDRSTRLEN]; 650 struct ifnet *rifp; 651 time_t uptime; 652 int changed = 0; 653 654 NET_ASSERT_LOCKED_EXCLUSIVE(); 655 KASSERT(sdl != NULL); 656 657 /* 658 * This can happen if the entry has been deleted by another CPU 659 * after we found it. 660 */ 661 if (la == NULL) 662 return (0); 663 664 uptime = getuptime(); 665 if (sdl->sdl_alen > 0) { 666 if (memcmp(ea->arp_sha, LLADDR(sdl), sdl->sdl_alen)) { 667 if (ISSET(rt->rt_flags, RTF_PERMANENT_ARP|RTF_LOCAL)) { 668 inet_ntop(AF_INET, spa, addr, sizeof(addr)); 669 log(LOG_WARNING, "arp: attempt to overwrite " 670 "permanent entry for %s by %s on %s\n", addr, 671 ether_sprintf(ea->arp_sha), ifp->if_xname); 672 return (-1); 673 } else if (rt->rt_ifidx != ifp->if_index) { 674#if NCARP > 0 675 if (ifp->if_type != IFT_CARP) 676#endif 677 { 678 rifp = if_get(rt->rt_ifidx); 679 if (rifp == NULL) 680 return (-1); 681 inet_ntop(AF_INET, spa, addr, 682 sizeof(addr)); 683 log(LOG_WARNING, "arp: attempt to " 684 "overwrite entry for %s on %s by " 685 "%s on %s\n", addr, rifp->if_xname, 686 ether_sprintf(ea->arp_sha), 687 ifp->if_xname); 688 if_put(rifp); 689 } 690 return (-1); 691 } else { 692 inet_ntop(AF_INET, spa, addr, sizeof(addr)); 693 log(LOG_INFO, "arp info overwritten for %s by " 694 "%s on %s\n", addr, 695 ether_sprintf(ea->arp_sha), ifp->if_xname); 696 rt->rt_expire = 1;/* no longer static */ 697 } 698 changed = 1; 699 } 700 } else if (!if_isconnected(ifp, rt->rt_ifidx)) { 701 rifp = if_get(rt->rt_ifidx); 702 if (rifp == NULL) 703 return (-1); 704 inet_ntop(AF_INET, spa, addr, sizeof(addr)); 705 log(LOG_WARNING, "arp: attempt to add entry for %s on %s by %s" 706 " on %s\n", addr, rifp->if_xname, 707 ether_sprintf(ea->arp_sha), ifp->if_xname); 708 if_put(rifp); 709 return (-1); 710 } 711 sdl->sdl_alen = sizeof(ea->arp_sha); 712 memcpy(LLADDR(sdl), ea->arp_sha, sizeof(ea->arp_sha)); 713 if (rt->rt_expire) 714 rt->rt_expire = uptime + arpt_keep; 715 rt->rt_flags &= ~RTF_REJECT; 716 717 /* Notify userland that an ARP resolution has been done. */ 718 if (la->la_asked || changed) { 719 rtm_send(rt, RTM_RESOLVE, 0, ifp->if_rdomain); 720 } 721 722 la->la_asked = 0; 723 la->la_refreshed = 0; 724 if_output_mq(ifp, &la->la_mq, &la_hold_total, rt_key(rt), rt); 725 726 return (0); 727} 728 729void 730arpinvalidate(struct rtentry *rt) 731{ 732 struct llinfo_arp *la; 733 struct sockaddr_dl *sdl = satosdl(rt->rt_gateway); 734 735 mtx_enter(&arp_mtx); 736 la = (struct llinfo_arp *)rt->rt_llinfo; 737 if (la == NULL) { 738 mtx_leave(&arp_mtx); 739 return; 740 } 741 atomic_sub_int(&la_hold_total, mq_purge(&la->la_mq)); 742 sdl->sdl_alen = 0; 743 la->la_asked = 0; 744 mtx_leave(&arp_mtx); 745} 746 747/* 748 * Free an arp entry. 749 */ 750void 751arptfree(struct rtentry *rt) 752{ 753 struct ifnet *ifp; 754 755 KASSERT(!ISSET(rt->rt_flags, RTF_LOCAL)); 756 arpinvalidate(rt); 757 758 ifp = if_get(rt->rt_ifidx); 759 if (ifp == NULL) 760 return; 761 if (!ISSET(rt->rt_flags, RTF_STATIC|RTF_CACHED)) 762 rtdeletemsg(rt, ifp, ifp->if_rdomain); 763 if_put(ifp); 764} 765 766/* 767 * Lookup or enter a new address in arptab. 768 */ 769struct rtentry * 770arplookup(struct in_addr *inp, int create, int proxy, u_int tableid) 771{ 772 struct rtentry *rt; 773 struct sockaddr_inarp sin; 774 int flags; 775 776 memset(&sin, 0, sizeof(sin)); 777 sin.sin_len = sizeof(sin); 778 sin.sin_family = AF_INET; 779 sin.sin_addr.s_addr = inp->s_addr; 780 sin.sin_other = proxy ? SIN_PROXY : 0; 781 flags = (create) ? RT_RESOLVE : 0; 782 783 rt = rtalloc((struct sockaddr *)&sin, flags, tableid); 784 if (!rtisvalid(rt) || ISSET(rt->rt_flags, RTF_GATEWAY) || 785 !ISSET(rt->rt_flags, RTF_LLINFO) || 786 rt->rt_gateway->sa_family != AF_LINK) { 787 rtfree(rt); 788 return (NULL); 789 } 790 791 if (proxy && !ISSET(rt->rt_flags, RTF_ANNOUNCE)) { 792 while ((rt = rtable_iterate(rt)) != NULL) { 793 if (ISSET(rt->rt_flags, RTF_ANNOUNCE)) { 794 break; 795 } 796 } 797 } 798 799 return (rt); 800} 801 802/* 803 * Check whether we do proxy ARP for this address and we point to ourselves. 804 */ 805int 806arpproxy(struct in_addr in, unsigned int rtableid) 807{ 808 struct sockaddr_dl *sdl; 809 struct rtentry *rt; 810 struct ifnet *ifp; 811 int found = 0; 812 813 rt = arplookup(&in, 0, SIN_PROXY, rtableid); 814 if (!rtisvalid(rt)) { 815 rtfree(rt); 816 return (0); 817 } 818 819 /* Check that arp information are correct. */ 820 sdl = satosdl(rt->rt_gateway); 821 if (sdl->sdl_alen != ETHER_ADDR_LEN) { 822 rtfree(rt); 823 return (0); 824 } 825 826 ifp = if_get(rt->rt_ifidx); 827 if (ifp == NULL) { 828 rtfree(rt); 829 return (0); 830 } 831 832 if (!memcmp(LLADDR(sdl), LLADDR(ifp->if_sadl), sdl->sdl_alen)) 833 found = 1; 834 835 if_put(ifp); 836 rtfree(rt); 837 return (found); 838} 839 840/* 841 * Called from Ethernet interrupt handlers 842 * when ether packet type ETHERTYPE_REVARP 843 * is received. Common length and type checks are done here, 844 * then the protocol-specific routine is called. 845 */ 846void 847revarpinput(struct ifnet *ifp, struct mbuf *m) 848{ 849 if ((m = arppullup(m)) == NULL) 850 return; 851 in_revarpinput(ifp, m); 852} 853 854/* 855 * RARP for Internet protocols on Ethernet. 856 * Algorithm is that given in RFC 903. 857 * We are only using for bootstrap purposes to get an ip address for one of 858 * our interfaces. Thus we support no user-interface. 859 * 860 * Since the contents of the RARP reply are specific to the interface that 861 * sent the request, this code must ensure that they are properly associated. 862 * 863 * Note: also supports ARP via RARP packets, per the RFC. 864 */ 865void 866in_revarpinput(struct ifnet *ifp, struct mbuf *m) 867{ 868 struct ether_arp *ar; 869 int op; 870 871 ar = mtod(m, struct ether_arp *); 872 op = ntohs(ar->arp_op); 873 switch (op) { 874 case ARPOP_REQUEST: 875 case ARPOP_REPLY: /* per RFC */ 876 niq_enqueue(&arpinq, m); 877 return; 878 case ARPOP_REVREPLY: 879 break; 880 case ARPOP_REVREQUEST: /* handled by rarpd(8) */ 881 default: 882 goto out; 883 } 884#ifdef NFSCLIENT 885 if (revarp_ifidx == 0) 886 goto out; 887 if (revarp_ifidx != m->m_pkthdr.ph_ifidx) /* !same interface */ 888 goto out; 889 if (revarp_finished) 890 goto wake; 891 if (memcmp(ar->arp_tha, LLADDR(ifp->if_sadl), sizeof(ar->arp_tha))) 892 goto out; 893 memcpy(&revarp_srvip, ar->arp_spa, sizeof(revarp_srvip)); 894 memcpy(&revarp_myip, ar->arp_tpa, sizeof(revarp_myip)); 895 revarp_finished = 1; 896wake: /* Do wakeup every time in case it was missed. */ 897 wakeup((caddr_t)&revarp_myip); 898#endif /* NFSCLIENT */ 899 900out: 901 m_freem(m); 902} 903 904/* 905 * Send a RARP request for the ip address of the specified interface. 906 * The request should be RFC 903-compliant. 907 */ 908void 909revarprequest(struct ifnet *ifp) 910{ 911 struct sockaddr sa; 912 struct mbuf *m; 913 struct ether_header *eh; 914 struct ether_arp *ea; 915 struct arpcom *ac = (struct arpcom *)ifp; 916 917 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 918 return; 919 m->m_len = sizeof(*ea); 920 m->m_pkthdr.len = sizeof(*ea); 921 m->m_pkthdr.ph_rtableid = ifp->if_rdomain; 922 m->m_pkthdr.pf.prio = ifp->if_llprio; 923 m_align(m, sizeof(*ea)); 924 ea = mtod(m, struct ether_arp *); 925 eh = (struct ether_header *)sa.sa_data; 926 memset(ea, 0, sizeof(*ea)); 927 memcpy(eh->ether_dhost, etherbroadcastaddr, sizeof(eh->ether_dhost)); 928 eh->ether_type = htons(ETHERTYPE_REVARP); 929 ea->arp_hrd = htons(ARPHRD_ETHER); 930 ea->arp_pro = htons(ETHERTYPE_IP); 931 ea->arp_hln = sizeof(ea->arp_sha); /* hardware address length */ 932 ea->arp_pln = sizeof(ea->arp_spa); /* protocol address length */ 933 ea->arp_op = htons(ARPOP_REVREQUEST); 934 memcpy(eh->ether_shost, ac->ac_enaddr, sizeof(ea->arp_tha)); 935 memcpy(ea->arp_sha, ac->ac_enaddr, sizeof(ea->arp_sha)); 936 memcpy(ea->arp_tha, ac->ac_enaddr, sizeof(ea->arp_tha)); 937 sa.sa_family = pseudo_AF_HDRCMPLT; 938 sa.sa_len = sizeof(sa); 939 m->m_flags |= M_BCAST; 940 ifp->if_output(ifp, m, &sa, NULL); 941} 942 943#ifdef NFSCLIENT 944/* 945 * RARP for the ip address of the specified interface, but also 946 * save the ip address of the server that sent the answer. 947 * Timeout if no response is received. 948 */ 949int 950revarpwhoarewe(struct ifnet *ifp, struct in_addr *serv_in, 951 struct in_addr *clnt_in) 952{ 953 int result, count = 20; 954 955 if (revarp_finished) 956 return EIO; 957 958 revarp_ifidx = ifp->if_index; 959 while (count--) { 960 revarprequest(ifp); 961 result = tsleep_nsec(&revarp_myip, PSOCK, "revarp", 962 MSEC_TO_NSEC(500)); 963 if (result != EWOULDBLOCK) 964 break; 965 } 966 revarp_ifidx = 0; 967 if (!revarp_finished) 968 return ENETUNREACH; 969 970 memcpy(serv_in, &revarp_srvip, sizeof(*serv_in)); 971 memcpy(clnt_in, &revarp_myip, sizeof(*clnt_in)); 972 return 0; 973} 974 975/* For compatibility: only saves interface address. */ 976int 977revarpwhoami(struct in_addr *in, struct ifnet *ifp) 978{ 979 struct in_addr server; 980 return (revarpwhoarewe(ifp, &server, in)); 981} 982#endif /* NFSCLIENT */ 983