1 /*- 2 * Copyright (c) 1982, 1986, 1988, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 4. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * @(#)if_ether.c 8.1 (Berkeley) 6/10/93 30 */ 31 32 /* 33 * Ethernet address resolution protocol. 34 * TODO: 35 * add "inuse/lock" bit (or ref. count) along with valid bit 36 */ 37 38 #include <sys/cdefs.h> 39 __FBSDID("$FreeBSD$"); 40 41 #include "opt_inet.h" 42 #include "opt_route.h" 43 #include "opt_mac.h" 44 #include "opt_carp.h" 45 46 #include <sys/param.h> 47 #include <sys/kernel.h> 48 #include <sys/queue.h> 49 #include <sys/sysctl.h> 50 #include <sys/systm.h> 51 #include <sys/mbuf.h> 52 #include <sys/malloc.h> 53 #include <sys/proc.h> 54 #include <sys/socket.h> 55 #include <sys/syslog.h> 56 #include <sys/vimage.h> 57 58 #include <net/if.h> 59 #include <net/if_dl.h> 60 #include <net/if_types.h> 61 #include <net/route.h> 62 #include <net/netisr.h> 63 #include <net/if_llc.h> 64 #include <net/ethernet.h> 65 #include <net/vnet.h> 66 67 #include <netinet/in.h> 68 #include <netinet/in_var.h> 69 #include <net/if_llatbl.h> 70 #include <netinet/if_ether.h> 71 #include <netinet/vinet.h> 72 73 #include <net/if_arc.h> 74 #include <net/iso88025.h> 75 76 #ifdef DEV_CARP 77 #include <netinet/ip_carp.h> 78 #endif 79 80 #include <security/mac/mac_framework.h> 81 82 #define SIN(s) ((struct sockaddr_in *)s) 83 #define SDL(s) ((struct sockaddr_dl *)s) 84 85 SYSCTL_DECL(_net_link_ether); 86 SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, ""); 87 88 /* timer values */ 89 #ifdef VIMAGE_GLOBALS 90 static int arpt_keep; /* once resolved, good for 20 more minutes */ 91 static int arp_maxtries; 92 int useloopback; /* use loopback interface for local traffic */ 93 static int arp_proxyall; 94 #endif 95 96 SYSCTL_V_INT(V_NET, vnet_inet, _net_link_ether_inet, OID_AUTO, max_age, 97 CTLFLAG_RW, arpt_keep, 0, "ARP entry lifetime in seconds"); 98 99 static struct ifqueue arpintrq; 100 101 SYSCTL_V_INT(V_NET, vnet_inet, _net_link_ether_inet, OID_AUTO, maxtries, 102 CTLFLAG_RW, arp_maxtries, 0, 103 "ARP resolution attempts before returning error"); 104 SYSCTL_V_INT(V_NET, vnet_inet, _net_link_ether_inet, OID_AUTO, useloopback, 105 CTLFLAG_RW, useloopback, 0, 106 "Use the loopback interface for local traffic"); 107 SYSCTL_V_INT(V_NET, vnet_inet, _net_link_ether_inet, OID_AUTO, proxyall, 108 CTLFLAG_RW, arp_proxyall, 0, 109 "Enable proxy ARP for all suitable requests"); 110 111 static void arp_init(void); 112 static int arp_iattach(const void *); 113 void arprequest(struct ifnet *, 114 struct in_addr *, struct in_addr *, u_char *); 115 static void arpintr(struct mbuf *); 116 static void arptimer(void *); 117 #ifdef INET 118 static void in_arpinput(struct mbuf *); 119 #endif 120 121 #ifndef VIMAGE_GLOBALS 122 static const vnet_modinfo_t vnet_arp_modinfo = { 123 .vmi_id = VNET_MOD_ARP, 124 .vmi_name = "arp", 125 .vmi_dependson = VNET_MOD_INET, 126 .vmi_iattach = arp_iattach 127 }; 128 #endif /* !VIMAGE_GLOBALS */ 129 130 #ifdef AF_INET 131 void arp_ifscrub(struct ifnet *ifp, uint32_t addr); 132 133 /* 134 * called by in_ifscrub to remove entry from the table when 135 * the interface goes away 136 */ 137 void 138 arp_ifscrub(struct ifnet *ifp, uint32_t addr) 139 { 140 struct sockaddr_in addr4; 141 142 bzero((void *)&addr4, sizeof(addr4)); 143 addr4.sin_len = sizeof(addr4); 144 addr4.sin_family = AF_INET; 145 addr4.sin_addr.s_addr = addr; 146 CURVNET_SET(ifp->if_vnet); 147 IF_AFDATA_LOCK(ifp); 148 lla_lookup(LLTABLE(ifp), (LLE_DELETE | LLE_IFADDR), 149 (struct sockaddr *)&addr4); 150 IF_AFDATA_UNLOCK(ifp); 151 CURVNET_RESTORE(); 152 } 153 #endif 154 155 /* 156 * Timeout routine. Age arp_tab entries periodically. 157 */ 158 static void 159 arptimer(void *arg) 160 { 161 struct ifnet *ifp; 162 struct llentry *lle = (struct llentry *)arg; 163 164 if (lle == NULL) { 165 panic("%s: NULL entry!\n", __func__); 166 return; 167 } 168 ifp = lle->lle_tbl->llt_ifp; 169 IF_AFDATA_LOCK(ifp); 170 LLE_WLOCK(lle); 171 if (((lle->la_flags & LLE_DELETED) 172 || (time_second >= lle->la_expire)) 173 && (!callout_pending(&lle->la_timer) && 174 callout_active(&lle->la_timer))) 175 (void) llentry_free(lle); 176 else { 177 /* 178 * Still valid, just drop our reference 179 */ 180 LLE_FREE_LOCKED(lle); 181 } 182 IF_AFDATA_UNLOCK(ifp); 183 } 184 185 /* 186 * Broadcast an ARP request. Caller specifies: 187 * - arp header source ip address 188 * - arp header target ip address 189 * - arp header source ethernet address 190 */ 191 void 192 arprequest(struct ifnet *ifp, struct in_addr *sip, struct in_addr *tip, 193 u_char *enaddr) 194 { 195 struct mbuf *m; 196 struct arphdr *ah; 197 struct sockaddr sa; 198 199 if (sip == NULL) { 200 /* XXX don't believe this can happen (or explain why) */ 201 /* 202 * The caller did not supply a source address, try to find 203 * a compatible one among those assigned to this interface. 204 */ 205 struct ifaddr *ifa; 206 207 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) { 208 if (!ifa->ifa_addr || 209 ifa->ifa_addr->sa_family != AF_INET) 210 continue; 211 sip = &SIN(ifa->ifa_addr)->sin_addr; 212 if (0 == ((sip->s_addr ^ tip->s_addr) & 213 SIN(ifa->ifa_netmask)->sin_addr.s_addr) ) 214 break; /* found it. */ 215 } 216 if (sip == NULL) { 217 printf("%s: cannot find matching address\n", __func__); 218 return; 219 } 220 } 221 222 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 223 return; 224 m->m_len = sizeof(*ah) + 2*sizeof(struct in_addr) + 225 2*ifp->if_data.ifi_addrlen; 226 m->m_pkthdr.len = m->m_len; 227 MH_ALIGN(m, m->m_len); 228 ah = mtod(m, struct arphdr *); 229 bzero((caddr_t)ah, m->m_len); 230 #ifdef MAC 231 mac_netinet_arp_send(ifp, m); 232 #endif 233 ah->ar_pro = htons(ETHERTYPE_IP); 234 ah->ar_hln = ifp->if_addrlen; /* hardware address length */ 235 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 236 ah->ar_op = htons(ARPOP_REQUEST); 237 bcopy((caddr_t)enaddr, (caddr_t)ar_sha(ah), ah->ar_hln); 238 bcopy((caddr_t)sip, (caddr_t)ar_spa(ah), ah->ar_pln); 239 bcopy((caddr_t)tip, (caddr_t)ar_tpa(ah), ah->ar_pln); 240 sa.sa_family = AF_ARP; 241 sa.sa_len = 2; 242 m->m_flags |= M_BCAST; 243 (*ifp->if_output)(ifp, m, &sa, NULL); 244 } 245 246 /* 247 * Resolve an IP address into an ethernet address. 248 * On input: 249 * ifp is the interface we use 250 * rt0 is the route to the final destination (possibly useless) 251 * m is the mbuf. May be NULL if we don't have a packet. 252 * dst is the next hop, 253 * desten is where we want the address. 254 * 255 * On success, desten is filled in and the function returns 0; 256 * If the packet must be held pending resolution, we return EWOULDBLOCK 257 * On other errors, we return the corresponding error code. 258 * Note that m_freem() handles NULL. 259 */ 260 int 261 arpresolve(struct ifnet *ifp, struct rtentry *rt0, struct mbuf *m, 262 struct sockaddr *dst, u_char *desten, struct llentry **lle) 263 { 264 INIT_VNET_INET(ifp->if_vnet); 265 struct llentry *la = 0; 266 u_int flags = 0; 267 int error, renew; 268 269 *lle = NULL; 270 if (m != NULL) { 271 if (m->m_flags & M_BCAST) { 272 /* broadcast */ 273 (void)memcpy(desten, 274 ifp->if_broadcastaddr, ifp->if_addrlen); 275 return (0); 276 } 277 if (m->m_flags & M_MCAST && ifp->if_type != IFT_ARCNET) { 278 /* multicast */ 279 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); 280 return (0); 281 } 282 } 283 /* XXXXX 284 */ 285 retry: 286 IF_AFDATA_RLOCK(ifp); 287 la = lla_lookup(LLTABLE(ifp), flags, dst); 288 IF_AFDATA_RUNLOCK(ifp); 289 if ((la == NULL) && ((flags & LLE_EXCLUSIVE) == 0) 290 && ((ifp->if_flags & (IFF_NOARP | IFF_STATICARP)) == 0)) { 291 flags |= (LLE_CREATE | LLE_EXCLUSIVE); 292 IF_AFDATA_WLOCK(ifp); 293 la = lla_lookup(LLTABLE(ifp), flags, dst); 294 IF_AFDATA_WUNLOCK(ifp); 295 } 296 if (la == NULL) { 297 if (flags & LLE_CREATE) 298 log(LOG_DEBUG, 299 "arpresolve: can't allocate llinfo for %s\n", 300 inet_ntoa(SIN(dst)->sin_addr)); 301 m_freem(m); 302 return (EINVAL); 303 } 304 305 if ((la->la_flags & LLE_VALID) && 306 ((la->la_flags & LLE_STATIC) || la->la_expire > time_uptime)) { 307 bcopy(&la->ll_addr, desten, ifp->if_addrlen); 308 /* 309 * If entry has an expiry time and it is approaching, 310 * see if we need to send an ARP request within this 311 * arpt_down interval. 312 */ 313 if (!(la->la_flags & LLE_STATIC) && 314 time_uptime + la->la_preempt > la->la_expire) { 315 arprequest(ifp, NULL, 316 &SIN(dst)->sin_addr, IF_LLADDR(ifp)); 317 318 la->la_preempt--; 319 } 320 321 *lle = la; 322 error = 0; 323 goto done; 324 } 325 326 if (la->la_flags & LLE_STATIC) { /* should not happen! */ 327 log(LOG_DEBUG, "arpresolve: ouch, empty static llinfo for %s\n", 328 inet_ntoa(SIN(dst)->sin_addr)); 329 m_freem(m); 330 error = EINVAL; 331 goto done; 332 } 333 334 renew = (la->la_asked == 0 || la->la_expire != time_uptime); 335 if ((renew || m != NULL) && (flags & LLE_EXCLUSIVE) == 0) { 336 flags |= LLE_EXCLUSIVE; 337 LLE_RUNLOCK(la); 338 goto retry; 339 } 340 /* 341 * There is an arptab entry, but no ethernet address 342 * response yet. Replace the held mbuf with this 343 * latest one. 344 */ 345 if (m != NULL) { 346 if (la->la_hold != NULL) 347 m_freem(la->la_hold); 348 la->la_hold = m; 349 if (renew == 0 && (flags & LLE_EXCLUSIVE)) { 350 flags &= ~LLE_EXCLUSIVE; 351 LLE_DOWNGRADE(la); 352 } 353 354 } 355 /* 356 * Return EWOULDBLOCK if we have tried less than arp_maxtries. It 357 * will be masked by ether_output(). Return EHOSTDOWN/EHOSTUNREACH 358 * if we have already sent arp_maxtries ARP requests. Retransmit the 359 * ARP request, but not faster than one request per second. 360 */ 361 if (la->la_asked < V_arp_maxtries) 362 error = EWOULDBLOCK; /* First request. */ 363 else 364 error = 365 (rt0->rt_flags & RTF_GATEWAY) ? EHOSTDOWN : EHOSTUNREACH; 366 367 if (renew) { 368 LLE_ADDREF(la); 369 la->la_expire = time_uptime; 370 callout_reset(&la->la_timer, hz, arptimer, la); 371 la->la_asked++; 372 LLE_WUNLOCK(la); 373 arprequest(ifp, NULL, &SIN(dst)->sin_addr, 374 IF_LLADDR(ifp)); 375 return (error); 376 } 377 done: 378 if (flags & LLE_EXCLUSIVE) 379 LLE_WUNLOCK(la); 380 else 381 LLE_RUNLOCK(la); 382 return (error); 383 } 384 385 /* 386 * Common length and type checks are done here, 387 * then the protocol-specific routine is called. 388 */ 389 static void 390 arpintr(struct mbuf *m) 391 { 392 struct arphdr *ar; 393 394 if (m->m_len < sizeof(struct arphdr) && 395 ((m = m_pullup(m, sizeof(struct arphdr))) == NULL)) { 396 log(LOG_ERR, "arp: runt packet -- m_pullup failed\n"); 397 return; 398 } 399 ar = mtod(m, struct arphdr *); 400 401 if (ntohs(ar->ar_hrd) != ARPHRD_ETHER && 402 ntohs(ar->ar_hrd) != ARPHRD_IEEE802 && 403 ntohs(ar->ar_hrd) != ARPHRD_ARCNET && 404 ntohs(ar->ar_hrd) != ARPHRD_IEEE1394) { 405 log(LOG_ERR, "arp: unknown hardware address format (0x%2D)\n", 406 (unsigned char *)&ar->ar_hrd, ""); 407 m_freem(m); 408 return; 409 } 410 411 if (m->m_len < arphdr_len(ar)) { 412 if ((m = m_pullup(m, arphdr_len(ar))) == NULL) { 413 log(LOG_ERR, "arp: runt packet\n"); 414 m_freem(m); 415 return; 416 } 417 ar = mtod(m, struct arphdr *); 418 } 419 420 switch (ntohs(ar->ar_pro)) { 421 #ifdef INET 422 case ETHERTYPE_IP: 423 in_arpinput(m); 424 return; 425 #endif 426 } 427 m_freem(m); 428 } 429 430 #ifdef INET 431 /* 432 * ARP for Internet protocols on 10 Mb/s Ethernet. 433 * Algorithm is that given in RFC 826. 434 * In addition, a sanity check is performed on the sender 435 * protocol address, to catch impersonators. 436 * We no longer handle negotiations for use of trailer protocol: 437 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 438 * along with IP replies if we wanted trailers sent to us, 439 * and also sent them in response to IP replies. 440 * This allowed either end to announce the desire to receive 441 * trailer packets. 442 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 443 * but formerly didn't normally send requests. 444 */ 445 static int log_arp_wrong_iface = 1; 446 static int log_arp_movements = 1; 447 static int log_arp_permanent_modify = 1; 448 449 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW, 450 &log_arp_wrong_iface, 0, 451 "log arp packets arriving on the wrong interface"); 452 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_movements, CTLFLAG_RW, 453 &log_arp_movements, 0, 454 "log arp replies from MACs different than the one in the cache"); 455 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_permanent_modify, CTLFLAG_RW, 456 &log_arp_permanent_modify, 0, 457 "log arp replies from MACs different than the one in the permanent arp entry"); 458 459 460 static void 461 in_arpinput(struct mbuf *m) 462 { 463 struct arphdr *ah; 464 struct ifnet *ifp = m->m_pkthdr.rcvif; 465 struct llentry *la = NULL; 466 struct rtentry *rt; 467 struct ifaddr *ifa; 468 struct in_ifaddr *ia; 469 struct sockaddr sa; 470 struct in_addr isaddr, itaddr, myaddr; 471 u_int8_t *enaddr = NULL; 472 int op, flags; 473 struct mbuf *m0; 474 int req_len; 475 int bridged = 0, is_bridge = 0; 476 #ifdef DEV_CARP 477 int carp_match = 0; 478 #endif 479 struct sockaddr_in sin; 480 sin.sin_len = sizeof(struct sockaddr_in); 481 sin.sin_family = AF_INET; 482 sin.sin_addr.s_addr = 0; 483 INIT_VNET_INET(ifp->if_vnet); 484 485 if (ifp->if_bridge) 486 bridged = 1; 487 if (ifp->if_type == IFT_BRIDGE) 488 is_bridge = 1; 489 490 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 491 if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) { 492 log(LOG_ERR, "in_arp: runt packet -- m_pullup failed\n"); 493 return; 494 } 495 496 ah = mtod(m, struct arphdr *); 497 op = ntohs(ah->ar_op); 498 (void)memcpy(&isaddr, ar_spa(ah), sizeof (isaddr)); 499 (void)memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr)); 500 501 /* 502 * For a bridge, we want to check the address irrespective 503 * of the receive interface. (This will change slightly 504 * when we have clusters of interfaces). 505 * If the interface does not match, but the recieving interface 506 * is part of carp, we call carp_iamatch to see if this is a 507 * request for the virtual host ip. 508 * XXX: This is really ugly! 509 */ 510 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) { 511 if (((bridged && ia->ia_ifp->if_bridge != NULL) || 512 ia->ia_ifp == ifp) && 513 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) 514 goto match; 515 #ifdef DEV_CARP 516 if (ifp->if_carp != NULL && 517 carp_iamatch(ifp->if_carp, ia, &isaddr, &enaddr) && 518 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) { 519 carp_match = 1; 520 goto match; 521 } 522 #endif 523 } 524 LIST_FOREACH(ia, INADDR_HASH(isaddr.s_addr), ia_hash) 525 if (((bridged && ia->ia_ifp->if_bridge != NULL) || 526 ia->ia_ifp == ifp) && 527 isaddr.s_addr == ia->ia_addr.sin_addr.s_addr) 528 goto match; 529 530 #define BDG_MEMBER_MATCHES_ARP(addr, ifp, ia) \ 531 (ia->ia_ifp->if_bridge == ifp->if_softc && \ 532 !bcmp(IF_LLADDR(ia->ia_ifp), IF_LLADDR(ifp), ifp->if_addrlen) && \ 533 addr == ia->ia_addr.sin_addr.s_addr) 534 /* 535 * Check the case when bridge shares its MAC address with 536 * some of its children, so packets are claimed by bridge 537 * itself (bridge_input() does it first), but they are really 538 * meant to be destined to the bridge member. 539 */ 540 if (is_bridge) { 541 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) { 542 if (BDG_MEMBER_MATCHES_ARP(itaddr.s_addr, ifp, ia)) { 543 ifp = ia->ia_ifp; 544 goto match; 545 } 546 } 547 } 548 #undef BDG_MEMBER_MATCHES_ARP 549 550 /* 551 * No match, use the first inet address on the receive interface 552 * as a dummy address for the rest of the function. 553 */ 554 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) 555 if (ifa->ifa_addr->sa_family == AF_INET) { 556 ia = ifatoia(ifa); 557 goto match; 558 } 559 /* 560 * If bridging, fall back to using any inet address. 561 */ 562 if (!bridged || (ia = TAILQ_FIRST(&V_in_ifaddrhead)) == NULL) 563 goto drop; 564 match: 565 if (!enaddr) 566 enaddr = (u_int8_t *)IF_LLADDR(ifp); 567 myaddr = ia->ia_addr.sin_addr; 568 if (!bcmp(ar_sha(ah), enaddr, ifp->if_addrlen)) 569 goto drop; /* it's from me, ignore it. */ 570 if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) { 571 log(LOG_ERR, 572 "arp: link address is broadcast for IP address %s!\n", 573 inet_ntoa(isaddr)); 574 goto drop; 575 } 576 /* 577 * Warn if another host is using the same IP address, but only if the 578 * IP address isn't 0.0.0.0, which is used for DHCP only, in which 579 * case we suppress the warning to avoid false positive complaints of 580 * potential misconfiguration. 581 */ 582 if (!bridged && isaddr.s_addr == myaddr.s_addr && myaddr.s_addr != 0) { 583 log(LOG_ERR, 584 "arp: %*D is using my IP address %s on %s!\n", 585 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 586 inet_ntoa(isaddr), ifp->if_xname); 587 itaddr = myaddr; 588 goto reply; 589 } 590 if (ifp->if_flags & IFF_STATICARP) 591 goto reply; 592 593 bzero(&sin, sizeof(sin)); 594 sin.sin_len = sizeof(struct sockaddr_in); 595 sin.sin_family = AF_INET; 596 sin.sin_addr = isaddr; 597 flags = (itaddr.s_addr == myaddr.s_addr) ? LLE_CREATE : 0; 598 flags |= LLE_EXCLUSIVE; 599 IF_AFDATA_LOCK(ifp); 600 la = lla_lookup(LLTABLE(ifp), flags, (struct sockaddr *)&sin); 601 IF_AFDATA_UNLOCK(ifp); 602 if (la != NULL) { 603 /* the following is not an error when doing bridging */ 604 if (!bridged && la->lle_tbl->llt_ifp != ifp 605 #ifdef DEV_CARP 606 && (ifp->if_type != IFT_CARP || !carp_match) 607 #endif 608 ) { 609 if (log_arp_wrong_iface) 610 log(LOG_ERR, "arp: %s is on %s " 611 "but got reply from %*D on %s\n", 612 inet_ntoa(isaddr), 613 la->lle_tbl->llt_ifp->if_xname, 614 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 615 ifp->if_xname); 616 goto reply; 617 } 618 if ((la->la_flags & LLE_VALID) && 619 bcmp(ar_sha(ah), &la->ll_addr, ifp->if_addrlen)) { 620 if (la->la_flags & LLE_STATIC) { 621 log(LOG_ERR, 622 "arp: %*D attempts to modify permanent " 623 "entry for %s on %s\n", 624 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 625 inet_ntoa(isaddr), ifp->if_xname); 626 goto reply; 627 } 628 if (log_arp_movements) { 629 log(LOG_INFO, "arp: %s moved from %*D " 630 "to %*D on %s\n", 631 inet_ntoa(isaddr), 632 ifp->if_addrlen, 633 (u_char *)&la->ll_addr, ":", 634 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 635 ifp->if_xname); 636 } 637 } 638 639 if (ifp->if_addrlen != ah->ar_hln) { 640 log(LOG_WARNING, 641 "arp from %*D: addr len: new %d, i/f %d (ignored)", 642 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 643 ah->ar_hln, ifp->if_addrlen); 644 goto reply; 645 } 646 (void)memcpy(&la->ll_addr, ar_sha(ah), ifp->if_addrlen); 647 la->la_flags |= LLE_VALID; 648 649 if (!(la->la_flags & LLE_STATIC)) { 650 la->la_expire = time_uptime + V_arpt_keep; 651 callout_reset(&la->la_timer, hz * V_arpt_keep, 652 arptimer, la); 653 } 654 la->la_asked = 0; 655 la->la_preempt = V_arp_maxtries; 656 if (la->la_hold != NULL) { 657 m0 = la->la_hold; 658 la->la_hold = 0; 659 memcpy(&sa, L3_ADDR(la), sizeof(sa)); 660 LLE_WUNLOCK(la); 661 662 (*ifp->if_output)(ifp, m0, &sa, NULL); 663 return; 664 } 665 } 666 reply: 667 if (op != ARPOP_REQUEST) 668 goto drop; 669 670 if (itaddr.s_addr == myaddr.s_addr) { 671 /* Shortcut.. the receiving interface is the target. */ 672 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 673 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln); 674 } else { 675 struct llentry *lle = NULL; 676 677 if (!V_arp_proxyall) 678 goto drop; 679 680 sin.sin_addr = itaddr; 681 /* XXX MRT use table 0 for arp reply */ 682 rt = in_rtalloc1((struct sockaddr *)&sin, 0, 0UL, 0); 683 if (!rt) 684 goto drop; 685 686 /* 687 * Don't send proxies for nodes on the same interface 688 * as this one came out of, or we'll get into a fight 689 * over who claims what Ether address. 690 */ 691 if (!rt->rt_ifp || rt->rt_ifp == ifp) { 692 RTFREE_LOCKED(rt); 693 goto drop; 694 } 695 IF_AFDATA_LOCK(rt->rt_ifp); 696 lle = lla_lookup(LLTABLE(rt->rt_ifp), 0, (struct sockaddr *)&sin); 697 IF_AFDATA_UNLOCK(rt->rt_ifp); 698 RTFREE_LOCKED(rt); 699 700 if (lle != NULL) { 701 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 702 (void)memcpy(ar_sha(ah), &lle->ll_addr, ah->ar_hln); 703 LLE_RUNLOCK(lle); 704 } else 705 goto drop; 706 707 /* 708 * Also check that the node which sent the ARP packet 709 * is on the the interface we expect it to be on. This 710 * avoids ARP chaos if an interface is connected to the 711 * wrong network. 712 */ 713 sin.sin_addr = isaddr; 714 715 /* XXX MRT use table 0 for arp checks */ 716 rt = in_rtalloc1((struct sockaddr *)&sin, 0, 0UL, 0); 717 if (!rt) 718 goto drop; 719 if (rt->rt_ifp != ifp) { 720 log(LOG_INFO, "arp_proxy: ignoring request" 721 " from %s via %s, expecting %s\n", 722 inet_ntoa(isaddr), ifp->if_xname, 723 rt->rt_ifp->if_xname); 724 RTFREE_LOCKED(rt); 725 goto drop; 726 } 727 RTFREE_LOCKED(rt); 728 729 #ifdef DEBUG_PROXY 730 printf("arp: proxying for %s\n", 731 inet_ntoa(itaddr)); 732 #endif 733 } 734 735 if (la != NULL) 736 LLE_WUNLOCK(la); 737 if (itaddr.s_addr == myaddr.s_addr && 738 IN_LINKLOCAL(ntohl(itaddr.s_addr))) { 739 /* RFC 3927 link-local IPv4; always reply by broadcast. */ 740 #ifdef DEBUG_LINKLOCAL 741 printf("arp: sending reply for link-local addr %s\n", 742 inet_ntoa(itaddr)); 743 #endif 744 m->m_flags |= M_BCAST; 745 m->m_flags &= ~M_MCAST; 746 } else { 747 /* default behaviour; never reply by broadcast. */ 748 m->m_flags &= ~(M_BCAST|M_MCAST); 749 } 750 (void)memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln); 751 (void)memcpy(ar_spa(ah), &itaddr, ah->ar_pln); 752 ah->ar_op = htons(ARPOP_REPLY); 753 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 754 m->m_len = sizeof(*ah) + (2 * ah->ar_pln) + (2 * ah->ar_hln); 755 m->m_pkthdr.len = m->m_len; 756 sa.sa_family = AF_ARP; 757 sa.sa_len = 2; 758 (*ifp->if_output)(ifp, m, &sa, NULL); 759 return; 760 761 drop: 762 if (la != NULL) 763 LLE_WUNLOCK(la); 764 m_freem(m); 765 } 766 #endif 767 768 void 769 arp_ifinit(struct ifnet *ifp, struct ifaddr *ifa) 770 { 771 struct llentry *lle; 772 773 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY) { 774 arprequest(ifp, &IA_SIN(ifa)->sin_addr, 775 &IA_SIN(ifa)->sin_addr, IF_LLADDR(ifp)); 776 /* 777 * interface address is considered static entry 778 * because the output of the arp utility shows 779 * that L2 entry as permanent 780 */ 781 IF_AFDATA_LOCK(ifp); 782 lle = lla_lookup(LLTABLE(ifp), (LLE_CREATE | LLE_IFADDR | LLE_STATIC), 783 (struct sockaddr *)IA_SIN(ifa)); 784 IF_AFDATA_UNLOCK(ifp); 785 if (lle == NULL) 786 log(LOG_INFO, "arp_ifinit: cannot create arp " 787 "entry for interface address\n"); 788 else 789 LLE_RUNLOCK(lle); 790 } 791 ifa->ifa_rtrequest = NULL; 792 } 793 794 void 795 arp_ifinit2(struct ifnet *ifp, struct ifaddr *ifa, u_char *enaddr) 796 { 797 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY) 798 arprequest(ifp, &IA_SIN(ifa)->sin_addr, 799 &IA_SIN(ifa)->sin_addr, enaddr); 800 ifa->ifa_rtrequest = NULL; 801 } 802 803 static int 804 arp_iattach(const void *unused __unused) 805 { 806 INIT_VNET_INET(curvnet); 807 808 V_arpt_keep = (20*60); /* once resolved, good for 20 more minutes */ 809 V_arp_maxtries = 5; 810 V_useloopback = 1; /* use loopback interface for local traffic */ 811 V_arp_proxyall = 0; 812 813 return (0); 814 } 815 816 static void 817 arp_init(void) 818 { 819 820 #ifndef VIMAGE_GLOBALS 821 vnet_mod_register(&vnet_arp_modinfo); 822 #else 823 arp_iattach(NULL); 824 #endif 825 826 arpintrq.ifq_maxlen = 50; 827 mtx_init(&arpintrq.ifq_mtx, "arp_inq", NULL, MTX_DEF); 828 netisr_register(NETISR_ARP, arpintr, &arpintrq, 0); 829 } 830 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0); 831