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_carp.h" 44 45 #include <sys/param.h> 46 #include <sys/kernel.h> 47 #include <sys/queue.h> 48 #include <sys/sysctl.h> 49 #include <sys/systm.h> 50 #include <sys/mbuf.h> 51 #include <sys/malloc.h> 52 #include <sys/proc.h> 53 #include <sys/socket.h> 54 #include <sys/syslog.h> 55 #include <sys/vimage.h> 56 57 #include <net/if.h> 58 #include <net/if_dl.h> 59 #include <net/if_types.h> 60 #include <net/route.h> 61 #include <net/netisr.h> 62 #include <net/if_llc.h> 63 #include <net/ethernet.h> 64 #include <net/vnet.h> 65 66 #include <netinet/in.h> 67 #include <netinet/in_var.h> 68 #include <net/if_llatbl.h> 69 #include <netinet/if_ether.h> 70 #include <netinet/vinet.h> 71 72 #include <net/if_arc.h> 73 #include <net/iso88025.h> 74 75 #ifdef DEV_CARP 76 #include <netinet/ip_carp.h> 77 #endif 78 79 #include <security/mac/mac_framework.h> 80 81 #define SIN(s) ((struct sockaddr_in *)s) 82 #define SDL(s) ((struct sockaddr_dl *)s) 83 84 SYSCTL_DECL(_net_link_ether); 85 SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, ""); 86 87 /* timer values */ 88 #ifdef VIMAGE_GLOBALS 89 static int arpt_keep; /* once resolved, good for 20 more minutes */ 90 static int arp_maxtries; 91 int useloopback; /* use loopback interface for local traffic */ 92 static int arp_proxyall; 93 #endif 94 95 SYSCTL_V_INT(V_NET, vnet_inet, _net_link_ether_inet, OID_AUTO, max_age, 96 CTLFLAG_RW, arpt_keep, 0, "ARP entry lifetime in seconds"); 97 98 SYSCTL_V_INT(V_NET, vnet_inet, _net_link_ether_inet, OID_AUTO, maxtries, 99 CTLFLAG_RW, arp_maxtries, 0, 100 "ARP resolution attempts before returning error"); 101 SYSCTL_V_INT(V_NET, vnet_inet, _net_link_ether_inet, OID_AUTO, useloopback, 102 CTLFLAG_RW, useloopback, 0, 103 "Use the loopback interface for local traffic"); 104 SYSCTL_V_INT(V_NET, vnet_inet, _net_link_ether_inet, OID_AUTO, proxyall, 105 CTLFLAG_RW, arp_proxyall, 0, 106 "Enable proxy ARP for all suitable requests"); 107 108 static void arp_init(void); 109 static int arp_iattach(const void *); 110 void arprequest(struct ifnet *, 111 struct in_addr *, struct in_addr *, u_char *); 112 static void arpintr(struct mbuf *); 113 static void arptimer(void *); 114 #ifdef INET 115 static void in_arpinput(struct mbuf *); 116 #endif 117 118 static const struct netisr_handler arp_nh = { 119 .nh_name = "arp", 120 .nh_handler = arpintr, 121 .nh_proto = NETISR_ARP, 122 .nh_policy = NETISR_POLICY_SOURCE, 123 }; 124 125 #ifndef VIMAGE_GLOBALS 126 static const vnet_modinfo_t vnet_arp_modinfo = { 127 .vmi_id = VNET_MOD_ARP, 128 .vmi_name = "arp", 129 .vmi_dependson = VNET_MOD_INET, 130 .vmi_iattach = arp_iattach 131 }; 132 #endif /* !VIMAGE_GLOBALS */ 133 134 #ifdef AF_INET 135 void arp_ifscrub(struct ifnet *ifp, uint32_t addr); 136 137 /* 138 * called by in_ifscrub to remove entry from the table when 139 * the interface goes away 140 */ 141 void 142 arp_ifscrub(struct ifnet *ifp, uint32_t addr) 143 { 144 struct sockaddr_in addr4; 145 146 bzero((void *)&addr4, sizeof(addr4)); 147 addr4.sin_len = sizeof(addr4); 148 addr4.sin_family = AF_INET; 149 addr4.sin_addr.s_addr = addr; 150 CURVNET_SET(ifp->if_vnet); 151 IF_AFDATA_LOCK(ifp); 152 lla_lookup(LLTABLE(ifp), (LLE_DELETE | LLE_IFADDR), 153 (struct sockaddr *)&addr4); 154 IF_AFDATA_UNLOCK(ifp); 155 CURVNET_RESTORE(); 156 } 157 #endif 158 159 /* 160 * Timeout routine. Age arp_tab entries periodically. 161 */ 162 static void 163 arptimer(void *arg) 164 { 165 struct ifnet *ifp; 166 struct llentry *lle = (struct llentry *)arg; 167 168 if (lle == NULL) { 169 panic("%s: NULL entry!\n", __func__); 170 return; 171 } 172 ifp = lle->lle_tbl->llt_ifp; 173 IF_AFDATA_LOCK(ifp); 174 LLE_WLOCK(lle); 175 if (((lle->la_flags & LLE_DELETED) 176 || (time_second >= lle->la_expire)) 177 && (!callout_pending(&lle->la_timer) && 178 callout_active(&lle->la_timer))) 179 (void) llentry_free(lle); 180 else { 181 /* 182 * Still valid, just drop our reference 183 */ 184 LLE_FREE_LOCKED(lle); 185 } 186 IF_AFDATA_UNLOCK(ifp); 187 } 188 189 /* 190 * Broadcast an ARP request. Caller specifies: 191 * - arp header source ip address 192 * - arp header target ip address 193 * - arp header source ethernet address 194 */ 195 void 196 arprequest(struct ifnet *ifp, struct in_addr *sip, struct in_addr *tip, 197 u_char *enaddr) 198 { 199 struct mbuf *m; 200 struct arphdr *ah; 201 struct sockaddr sa; 202 203 if (sip == NULL) { 204 /* XXX don't believe this can happen (or explain why) */ 205 /* 206 * The caller did not supply a source address, try to find 207 * a compatible one among those assigned to this interface. 208 */ 209 struct ifaddr *ifa; 210 211 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) { 212 if (!ifa->ifa_addr || 213 ifa->ifa_addr->sa_family != AF_INET) 214 continue; 215 sip = &SIN(ifa->ifa_addr)->sin_addr; 216 if (0 == ((sip->s_addr ^ tip->s_addr) & 217 SIN(ifa->ifa_netmask)->sin_addr.s_addr) ) 218 break; /* found it. */ 219 } 220 if (sip == NULL) { 221 printf("%s: cannot find matching address\n", __func__); 222 return; 223 } 224 } 225 226 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 227 return; 228 m->m_len = sizeof(*ah) + 2*sizeof(struct in_addr) + 229 2*ifp->if_data.ifi_addrlen; 230 m->m_pkthdr.len = m->m_len; 231 MH_ALIGN(m, m->m_len); 232 ah = mtod(m, struct arphdr *); 233 bzero((caddr_t)ah, m->m_len); 234 #ifdef MAC 235 mac_netinet_arp_send(ifp, m); 236 #endif 237 ah->ar_pro = htons(ETHERTYPE_IP); 238 ah->ar_hln = ifp->if_addrlen; /* hardware address length */ 239 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 240 ah->ar_op = htons(ARPOP_REQUEST); 241 bcopy((caddr_t)enaddr, (caddr_t)ar_sha(ah), ah->ar_hln); 242 bcopy((caddr_t)sip, (caddr_t)ar_spa(ah), ah->ar_pln); 243 bcopy((caddr_t)tip, (caddr_t)ar_tpa(ah), ah->ar_pln); 244 sa.sa_family = AF_ARP; 245 sa.sa_len = 2; 246 m->m_flags |= M_BCAST; 247 (*ifp->if_output)(ifp, m, &sa, NULL); 248 } 249 250 /* 251 * Resolve an IP address into an ethernet address. 252 * On input: 253 * ifp is the interface we use 254 * rt0 is the route to the final destination (possibly useless) 255 * m is the mbuf. May be NULL if we don't have a packet. 256 * dst is the next hop, 257 * desten is where we want the address. 258 * 259 * On success, desten is filled in and the function returns 0; 260 * If the packet must be held pending resolution, we return EWOULDBLOCK 261 * On other errors, we return the corresponding error code. 262 * Note that m_freem() handles NULL. 263 */ 264 int 265 arpresolve(struct ifnet *ifp, struct rtentry *rt0, struct mbuf *m, 266 struct sockaddr *dst, u_char *desten, struct llentry **lle) 267 { 268 INIT_VNET_INET(ifp->if_vnet); 269 struct llentry *la = 0; 270 u_int flags = 0; 271 int error, renew; 272 273 *lle = NULL; 274 if (m != NULL) { 275 if (m->m_flags & M_BCAST) { 276 /* broadcast */ 277 (void)memcpy(desten, 278 ifp->if_broadcastaddr, ifp->if_addrlen); 279 return (0); 280 } 281 if (m->m_flags & M_MCAST && ifp->if_type != IFT_ARCNET) { 282 /* multicast */ 283 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); 284 return (0); 285 } 286 } 287 /* XXXXX 288 */ 289 retry: 290 IF_AFDATA_RLOCK(ifp); 291 la = lla_lookup(LLTABLE(ifp), flags, dst); 292 IF_AFDATA_RUNLOCK(ifp); 293 if ((la == NULL) && ((flags & LLE_EXCLUSIVE) == 0) 294 && ((ifp->if_flags & (IFF_NOARP | IFF_STATICARP)) == 0)) { 295 flags |= (LLE_CREATE | LLE_EXCLUSIVE); 296 IF_AFDATA_WLOCK(ifp); 297 la = lla_lookup(LLTABLE(ifp), flags, dst); 298 IF_AFDATA_WUNLOCK(ifp); 299 } 300 if (la == NULL) { 301 if (flags & LLE_CREATE) 302 log(LOG_DEBUG, 303 "arpresolve: can't allocate llinfo for %s\n", 304 inet_ntoa(SIN(dst)->sin_addr)); 305 m_freem(m); 306 return (EINVAL); 307 } 308 309 if ((la->la_flags & LLE_VALID) && 310 ((la->la_flags & LLE_STATIC) || la->la_expire > time_uptime)) { 311 bcopy(&la->ll_addr, desten, ifp->if_addrlen); 312 /* 313 * If entry has an expiry time and it is approaching, 314 * see if we need to send an ARP request within this 315 * arpt_down interval. 316 */ 317 if (!(la->la_flags & LLE_STATIC) && 318 time_uptime + la->la_preempt > la->la_expire) { 319 arprequest(ifp, NULL, 320 &SIN(dst)->sin_addr, IF_LLADDR(ifp)); 321 322 la->la_preempt--; 323 } 324 325 *lle = la; 326 error = 0; 327 goto done; 328 } 329 330 if (la->la_flags & LLE_STATIC) { /* should not happen! */ 331 log(LOG_DEBUG, "arpresolve: ouch, empty static llinfo for %s\n", 332 inet_ntoa(SIN(dst)->sin_addr)); 333 m_freem(m); 334 error = EINVAL; 335 goto done; 336 } 337 338 renew = (la->la_asked == 0 || la->la_expire != time_uptime); 339 if ((renew || m != NULL) && (flags & LLE_EXCLUSIVE) == 0) { 340 flags |= LLE_EXCLUSIVE; 341 LLE_RUNLOCK(la); 342 goto retry; 343 } 344 /* 345 * There is an arptab entry, but no ethernet address 346 * response yet. Replace the held mbuf with this 347 * latest one. 348 */ 349 if (m != NULL) { 350 if (la->la_hold != NULL) 351 m_freem(la->la_hold); 352 la->la_hold = m; 353 if (renew == 0 && (flags & LLE_EXCLUSIVE)) { 354 flags &= ~LLE_EXCLUSIVE; 355 LLE_DOWNGRADE(la); 356 } 357 358 } 359 /* 360 * Return EWOULDBLOCK if we have tried less than arp_maxtries. It 361 * will be masked by ether_output(). Return EHOSTDOWN/EHOSTUNREACH 362 * if we have already sent arp_maxtries ARP requests. Retransmit the 363 * ARP request, but not faster than one request per second. 364 */ 365 if (la->la_asked < V_arp_maxtries) 366 error = EWOULDBLOCK; /* First request. */ 367 else 368 error = 369 (rt0->rt_flags & RTF_GATEWAY) ? EHOSTDOWN : EHOSTUNREACH; 370 371 if (renew) { 372 LLE_ADDREF(la); 373 la->la_expire = time_uptime; 374 callout_reset(&la->la_timer, hz, arptimer, la); 375 la->la_asked++; 376 LLE_WUNLOCK(la); 377 arprequest(ifp, NULL, &SIN(dst)->sin_addr, 378 IF_LLADDR(ifp)); 379 return (error); 380 } 381 done: 382 if (flags & LLE_EXCLUSIVE) 383 LLE_WUNLOCK(la); 384 else 385 LLE_RUNLOCK(la); 386 return (error); 387 } 388 389 /* 390 * Common length and type checks are done here, 391 * then the protocol-specific routine is called. 392 */ 393 static void 394 arpintr(struct mbuf *m) 395 { 396 struct arphdr *ar; 397 398 if (m->m_len < sizeof(struct arphdr) && 399 ((m = m_pullup(m, sizeof(struct arphdr))) == NULL)) { 400 log(LOG_ERR, "arp: runt packet -- m_pullup failed\n"); 401 return; 402 } 403 ar = mtod(m, struct arphdr *); 404 405 if (ntohs(ar->ar_hrd) != ARPHRD_ETHER && 406 ntohs(ar->ar_hrd) != ARPHRD_IEEE802 && 407 ntohs(ar->ar_hrd) != ARPHRD_ARCNET && 408 ntohs(ar->ar_hrd) != ARPHRD_IEEE1394) { 409 log(LOG_ERR, "arp: unknown hardware address format (0x%2D)\n", 410 (unsigned char *)&ar->ar_hrd, ""); 411 m_freem(m); 412 return; 413 } 414 415 if (m->m_len < arphdr_len(ar)) { 416 if ((m = m_pullup(m, arphdr_len(ar))) == NULL) { 417 log(LOG_ERR, "arp: runt packet\n"); 418 m_freem(m); 419 return; 420 } 421 ar = mtod(m, struct arphdr *); 422 } 423 424 switch (ntohs(ar->ar_pro)) { 425 #ifdef INET 426 case ETHERTYPE_IP: 427 in_arpinput(m); 428 return; 429 #endif 430 } 431 m_freem(m); 432 } 433 434 #ifdef INET 435 /* 436 * ARP for Internet protocols on 10 Mb/s Ethernet. 437 * Algorithm is that given in RFC 826. 438 * In addition, a sanity check is performed on the sender 439 * protocol address, to catch impersonators. 440 * We no longer handle negotiations for use of trailer protocol: 441 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 442 * along with IP replies if we wanted trailers sent to us, 443 * and also sent them in response to IP replies. 444 * This allowed either end to announce the desire to receive 445 * trailer packets. 446 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 447 * but formerly didn't normally send requests. 448 */ 449 static int log_arp_wrong_iface = 1; 450 static int log_arp_movements = 1; 451 static int log_arp_permanent_modify = 1; 452 453 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW, 454 &log_arp_wrong_iface, 0, 455 "log arp packets arriving on the wrong interface"); 456 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_movements, CTLFLAG_RW, 457 &log_arp_movements, 0, 458 "log arp replies from MACs different than the one in the cache"); 459 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_permanent_modify, CTLFLAG_RW, 460 &log_arp_permanent_modify, 0, 461 "log arp replies from MACs different than the one in the permanent arp entry"); 462 463 464 static void 465 in_arpinput(struct mbuf *m) 466 { 467 struct arphdr *ah; 468 struct ifnet *ifp = m->m_pkthdr.rcvif; 469 struct llentry *la = NULL; 470 struct rtentry *rt; 471 struct ifaddr *ifa; 472 struct in_ifaddr *ia; 473 struct sockaddr sa; 474 struct in_addr isaddr, itaddr, myaddr; 475 u_int8_t *enaddr = NULL; 476 int op, flags; 477 struct mbuf *m0; 478 int req_len; 479 int bridged = 0, is_bridge = 0; 480 #ifdef DEV_CARP 481 int carp_match = 0; 482 #endif 483 struct sockaddr_in sin; 484 sin.sin_len = sizeof(struct sockaddr_in); 485 sin.sin_family = AF_INET; 486 sin.sin_addr.s_addr = 0; 487 INIT_VNET_INET(ifp->if_vnet); 488 489 if (ifp->if_bridge) 490 bridged = 1; 491 if (ifp->if_type == IFT_BRIDGE) 492 is_bridge = 1; 493 494 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 495 if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) { 496 log(LOG_ERR, "in_arp: runt packet -- m_pullup failed\n"); 497 return; 498 } 499 500 ah = mtod(m, struct arphdr *); 501 op = ntohs(ah->ar_op); 502 (void)memcpy(&isaddr, ar_spa(ah), sizeof (isaddr)); 503 (void)memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr)); 504 505 /* 506 * For a bridge, we want to check the address irrespective 507 * of the receive interface. (This will change slightly 508 * when we have clusters of interfaces). 509 * If the interface does not match, but the recieving interface 510 * is part of carp, we call carp_iamatch to see if this is a 511 * request for the virtual host ip. 512 * XXX: This is really ugly! 513 */ 514 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) { 515 if (((bridged && ia->ia_ifp->if_bridge != NULL) || 516 ia->ia_ifp == ifp) && 517 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) 518 goto match; 519 #ifdef DEV_CARP 520 if (ifp->if_carp != NULL && 521 carp_iamatch(ifp->if_carp, ia, &isaddr, &enaddr) && 522 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) { 523 carp_match = 1; 524 goto match; 525 } 526 #endif 527 } 528 LIST_FOREACH(ia, INADDR_HASH(isaddr.s_addr), ia_hash) 529 if (((bridged && ia->ia_ifp->if_bridge != NULL) || 530 ia->ia_ifp == ifp) && 531 isaddr.s_addr == ia->ia_addr.sin_addr.s_addr) 532 goto match; 533 534 #define BDG_MEMBER_MATCHES_ARP(addr, ifp, ia) \ 535 (ia->ia_ifp->if_bridge == ifp->if_softc && \ 536 !bcmp(IF_LLADDR(ia->ia_ifp), IF_LLADDR(ifp), ifp->if_addrlen) && \ 537 addr == ia->ia_addr.sin_addr.s_addr) 538 /* 539 * Check the case when bridge shares its MAC address with 540 * some of its children, so packets are claimed by bridge 541 * itself (bridge_input() does it first), but they are really 542 * meant to be destined to the bridge member. 543 */ 544 if (is_bridge) { 545 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) { 546 if (BDG_MEMBER_MATCHES_ARP(itaddr.s_addr, ifp, ia)) { 547 ifp = ia->ia_ifp; 548 goto match; 549 } 550 } 551 } 552 #undef BDG_MEMBER_MATCHES_ARP 553 554 /* 555 * No match, use the first inet address on the receive interface 556 * as a dummy address for the rest of the function. 557 */ 558 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) 559 if (ifa->ifa_addr->sa_family == AF_INET) { 560 ia = ifatoia(ifa); 561 goto match; 562 } 563 /* 564 * If bridging, fall back to using any inet address. 565 */ 566 if (!bridged || (ia = TAILQ_FIRST(&V_in_ifaddrhead)) == NULL) 567 goto drop; 568 match: 569 if (!enaddr) 570 enaddr = (u_int8_t *)IF_LLADDR(ifp); 571 myaddr = ia->ia_addr.sin_addr; 572 if (!bcmp(ar_sha(ah), enaddr, ifp->if_addrlen)) 573 goto drop; /* it's from me, ignore it. */ 574 if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) { 575 log(LOG_ERR, 576 "arp: link address is broadcast for IP address %s!\n", 577 inet_ntoa(isaddr)); 578 goto drop; 579 } 580 /* 581 * Warn if another host is using the same IP address, but only if the 582 * IP address isn't 0.0.0.0, which is used for DHCP only, in which 583 * case we suppress the warning to avoid false positive complaints of 584 * potential misconfiguration. 585 */ 586 if (!bridged && isaddr.s_addr == myaddr.s_addr && myaddr.s_addr != 0) { 587 log(LOG_ERR, 588 "arp: %*D is using my IP address %s on %s!\n", 589 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 590 inet_ntoa(isaddr), ifp->if_xname); 591 itaddr = myaddr; 592 goto reply; 593 } 594 if (ifp->if_flags & IFF_STATICARP) 595 goto reply; 596 597 bzero(&sin, sizeof(sin)); 598 sin.sin_len = sizeof(struct sockaddr_in); 599 sin.sin_family = AF_INET; 600 sin.sin_addr = isaddr; 601 flags = (itaddr.s_addr == myaddr.s_addr) ? LLE_CREATE : 0; 602 flags |= LLE_EXCLUSIVE; 603 IF_AFDATA_LOCK(ifp); 604 la = lla_lookup(LLTABLE(ifp), flags, (struct sockaddr *)&sin); 605 IF_AFDATA_UNLOCK(ifp); 606 if (la != NULL) { 607 /* the following is not an error when doing bridging */ 608 if (!bridged && la->lle_tbl->llt_ifp != ifp 609 #ifdef DEV_CARP 610 && (ifp->if_type != IFT_CARP || !carp_match) 611 #endif 612 ) { 613 if (log_arp_wrong_iface) 614 log(LOG_ERR, "arp: %s is on %s " 615 "but got reply from %*D on %s\n", 616 inet_ntoa(isaddr), 617 la->lle_tbl->llt_ifp->if_xname, 618 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 619 ifp->if_xname); 620 goto reply; 621 } 622 if ((la->la_flags & LLE_VALID) && 623 bcmp(ar_sha(ah), &la->ll_addr, ifp->if_addrlen)) { 624 if (la->la_flags & LLE_STATIC) { 625 log(LOG_ERR, 626 "arp: %*D attempts to modify permanent " 627 "entry for %s on %s\n", 628 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 629 inet_ntoa(isaddr), ifp->if_xname); 630 goto reply; 631 } 632 if (log_arp_movements) { 633 log(LOG_INFO, "arp: %s moved from %*D " 634 "to %*D on %s\n", 635 inet_ntoa(isaddr), 636 ifp->if_addrlen, 637 (u_char *)&la->ll_addr, ":", 638 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 639 ifp->if_xname); 640 } 641 } 642 643 if (ifp->if_addrlen != ah->ar_hln) { 644 log(LOG_WARNING, 645 "arp from %*D: addr len: new %d, i/f %d (ignored)", 646 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 647 ah->ar_hln, ifp->if_addrlen); 648 goto reply; 649 } 650 (void)memcpy(&la->ll_addr, ar_sha(ah), ifp->if_addrlen); 651 la->la_flags |= LLE_VALID; 652 653 if (!(la->la_flags & LLE_STATIC)) { 654 la->la_expire = time_uptime + V_arpt_keep; 655 callout_reset(&la->la_timer, hz * V_arpt_keep, 656 arptimer, la); 657 } 658 la->la_asked = 0; 659 la->la_preempt = V_arp_maxtries; 660 if (la->la_hold != NULL) { 661 m0 = la->la_hold; 662 la->la_hold = 0; 663 memcpy(&sa, L3_ADDR(la), sizeof(sa)); 664 LLE_WUNLOCK(la); 665 666 (*ifp->if_output)(ifp, m0, &sa, NULL); 667 return; 668 } 669 } 670 reply: 671 if (op != ARPOP_REQUEST) 672 goto drop; 673 674 if (itaddr.s_addr == myaddr.s_addr) { 675 /* Shortcut.. the receiving interface is the target. */ 676 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 677 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln); 678 } else { 679 struct llentry *lle = NULL; 680 681 if (!V_arp_proxyall) 682 goto drop; 683 684 sin.sin_addr = itaddr; 685 /* XXX MRT use table 0 for arp reply */ 686 rt = in_rtalloc1((struct sockaddr *)&sin, 0, 0UL, 0); 687 if (!rt) 688 goto drop; 689 690 /* 691 * Don't send proxies for nodes on the same interface 692 * as this one came out of, or we'll get into a fight 693 * over who claims what Ether address. 694 */ 695 if (!rt->rt_ifp || rt->rt_ifp == ifp) { 696 RTFREE_LOCKED(rt); 697 goto drop; 698 } 699 IF_AFDATA_LOCK(rt->rt_ifp); 700 lle = lla_lookup(LLTABLE(rt->rt_ifp), 0, (struct sockaddr *)&sin); 701 IF_AFDATA_UNLOCK(rt->rt_ifp); 702 RTFREE_LOCKED(rt); 703 704 if (lle != NULL) { 705 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 706 (void)memcpy(ar_sha(ah), &lle->ll_addr, ah->ar_hln); 707 LLE_RUNLOCK(lle); 708 } else 709 goto drop; 710 711 /* 712 * Also check that the node which sent the ARP packet 713 * is on the the interface we expect it to be on. This 714 * avoids ARP chaos if an interface is connected to the 715 * wrong network. 716 */ 717 sin.sin_addr = isaddr; 718 719 /* XXX MRT use table 0 for arp checks */ 720 rt = in_rtalloc1((struct sockaddr *)&sin, 0, 0UL, 0); 721 if (!rt) 722 goto drop; 723 if (rt->rt_ifp != ifp) { 724 log(LOG_INFO, "arp_proxy: ignoring request" 725 " from %s via %s, expecting %s\n", 726 inet_ntoa(isaddr), ifp->if_xname, 727 rt->rt_ifp->if_xname); 728 RTFREE_LOCKED(rt); 729 goto drop; 730 } 731 RTFREE_LOCKED(rt); 732 733 #ifdef DEBUG_PROXY 734 printf("arp: proxying for %s\n", 735 inet_ntoa(itaddr)); 736 #endif 737 } 738 739 if (la != NULL) 740 LLE_WUNLOCK(la); 741 if (itaddr.s_addr == myaddr.s_addr && 742 IN_LINKLOCAL(ntohl(itaddr.s_addr))) { 743 /* RFC 3927 link-local IPv4; always reply by broadcast. */ 744 #ifdef DEBUG_LINKLOCAL 745 printf("arp: sending reply for link-local addr %s\n", 746 inet_ntoa(itaddr)); 747 #endif 748 m->m_flags |= M_BCAST; 749 m->m_flags &= ~M_MCAST; 750 } else { 751 /* default behaviour; never reply by broadcast. */ 752 m->m_flags &= ~(M_BCAST|M_MCAST); 753 } 754 (void)memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln); 755 (void)memcpy(ar_spa(ah), &itaddr, ah->ar_pln); 756 ah->ar_op = htons(ARPOP_REPLY); 757 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 758 m->m_len = sizeof(*ah) + (2 * ah->ar_pln) + (2 * ah->ar_hln); 759 m->m_pkthdr.len = m->m_len; 760 sa.sa_family = AF_ARP; 761 sa.sa_len = 2; 762 (*ifp->if_output)(ifp, m, &sa, NULL); 763 return; 764 765 drop: 766 if (la != NULL) 767 LLE_WUNLOCK(la); 768 m_freem(m); 769 } 770 #endif 771 772 void 773 arp_ifinit(struct ifnet *ifp, struct ifaddr *ifa) 774 { 775 struct llentry *lle; 776 777 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY) { 778 arprequest(ifp, &IA_SIN(ifa)->sin_addr, 779 &IA_SIN(ifa)->sin_addr, IF_LLADDR(ifp)); 780 /* 781 * interface address is considered static entry 782 * because the output of the arp utility shows 783 * that L2 entry as permanent 784 */ 785 IF_AFDATA_LOCK(ifp); 786 lle = lla_lookup(LLTABLE(ifp), (LLE_CREATE | LLE_IFADDR | LLE_STATIC), 787 (struct sockaddr *)IA_SIN(ifa)); 788 IF_AFDATA_UNLOCK(ifp); 789 if (lle == NULL) 790 log(LOG_INFO, "arp_ifinit: cannot create arp " 791 "entry for interface address\n"); 792 else 793 LLE_RUNLOCK(lle); 794 } 795 ifa->ifa_rtrequest = NULL; 796 } 797 798 void 799 arp_ifinit2(struct ifnet *ifp, struct ifaddr *ifa, u_char *enaddr) 800 { 801 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY) 802 arprequest(ifp, &IA_SIN(ifa)->sin_addr, 803 &IA_SIN(ifa)->sin_addr, enaddr); 804 ifa->ifa_rtrequest = NULL; 805 } 806 807 static int 808 arp_iattach(const void *unused __unused) 809 { 810 INIT_VNET_INET(curvnet); 811 812 V_arpt_keep = (20*60); /* once resolved, good for 20 more minutes */ 813 V_arp_maxtries = 5; 814 V_useloopback = 1; /* use loopback interface for local traffic */ 815 V_arp_proxyall = 0; 816 817 return (0); 818 } 819 820 static void 821 arp_init(void) 822 { 823 824 #ifndef VIMAGE_GLOBALS 825 vnet_mod_register(&vnet_arp_modinfo); 826 #else 827 arp_iattach(NULL); 828 #endif 829 830 netisr_register(&arp_nh); 831 } 832 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0); 833