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 43 #include <sys/param.h> 44 #include <sys/kernel.h> 45 #include <sys/lock.h> 46 #include <sys/queue.h> 47 #include <sys/sysctl.h> 48 #include <sys/systm.h> 49 #include <sys/mbuf.h> 50 #include <sys/malloc.h> 51 #include <sys/proc.h> 52 #include <sys/rmlock.h> 53 #include <sys/socket.h> 54 #include <sys/syslog.h> 55 56 #include <net/if.h> 57 #include <net/if_var.h> 58 #include <net/if_dl.h> 59 #include <net/if_types.h> 60 #include <net/netisr.h> 61 #include <net/ethernet.h> 62 #include <net/route.h> 63 #include <net/vnet.h> 64 65 #include <netinet/in.h> 66 #include <netinet/in_var.h> 67 #include <net/if_llatbl.h> 68 #include <netinet/if_ether.h> 69 #ifdef INET 70 #include <netinet/ip_carp.h> 71 #endif 72 73 #include <security/mac/mac_framework.h> 74 75 #define SIN(s) ((const struct sockaddr_in *)(s)) 76 77 static struct timeval arp_lastlog; 78 static int arp_curpps; 79 static int arp_maxpps = 1; 80 81 /* Simple ARP state machine */ 82 enum arp_llinfo_state { 83 ARP_LLINFO_INCOMPLETE = 0, /* No LLE data */ 84 ARP_LLINFO_REACHABLE, /* LLE is valid */ 85 ARP_LLINFO_VERIFY, /* LLE is valid, need refresh */ 86 ARP_LLINFO_DELETED, /* LLE is deleted */ 87 }; 88 89 SYSCTL_DECL(_net_link_ether); 90 static SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, ""); 91 static SYSCTL_NODE(_net_link_ether, PF_ARP, arp, CTLFLAG_RW, 0, ""); 92 93 /* timer values */ 94 static VNET_DEFINE(int, arpt_keep) = (20*60); /* once resolved, good for 20 95 * minutes */ 96 static VNET_DEFINE(int, arp_maxtries) = 5; 97 static VNET_DEFINE(int, arp_proxyall) = 0; 98 static VNET_DEFINE(int, arpt_down) = 20; /* keep incomplete entries for 99 * 20 seconds */ 100 static VNET_DEFINE(int, arpt_rexmit) = 1; /* retransmit arp entries, sec*/ 101 VNET_PCPUSTAT_DEFINE(struct arpstat, arpstat); /* ARP statistics, see if_arp.h */ 102 VNET_PCPUSTAT_SYSINIT(arpstat); 103 104 #ifdef VIMAGE 105 VNET_PCPUSTAT_SYSUNINIT(arpstat); 106 #endif /* VIMAGE */ 107 108 static VNET_DEFINE(int, arp_maxhold) = 1; 109 110 #define V_arpt_keep VNET(arpt_keep) 111 #define V_arpt_down VNET(arpt_down) 112 #define V_arpt_rexmit VNET(arpt_rexmit) 113 #define V_arp_maxtries VNET(arp_maxtries) 114 #define V_arp_proxyall VNET(arp_proxyall) 115 #define V_arp_maxhold VNET(arp_maxhold) 116 117 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_VNET | CTLFLAG_RW, 118 &VNET_NAME(arpt_keep), 0, 119 "ARP entry lifetime in seconds"); 120 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_VNET | CTLFLAG_RW, 121 &VNET_NAME(arp_maxtries), 0, 122 "ARP resolution attempts before returning error"); 123 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_VNET | CTLFLAG_RW, 124 &VNET_NAME(arp_proxyall), 0, 125 "Enable proxy ARP for all suitable requests"); 126 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, wait, CTLFLAG_VNET | CTLFLAG_RW, 127 &VNET_NAME(arpt_down), 0, 128 "Incomplete ARP entry lifetime in seconds"); 129 SYSCTL_VNET_PCPUSTAT(_net_link_ether_arp, OID_AUTO, stats, struct arpstat, 130 arpstat, "ARP statistics (struct arpstat, net/if_arp.h)"); 131 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, maxhold, CTLFLAG_VNET | CTLFLAG_RW, 132 &VNET_NAME(arp_maxhold), 0, 133 "Number of packets to hold per ARP entry"); 134 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_log_per_second, 135 CTLFLAG_RW, &arp_maxpps, 0, 136 "Maximum number of remotely triggered ARP messages that can be " 137 "logged per second"); 138 139 #define ARP_LOG(pri, ...) do { \ 140 if (ppsratecheck(&arp_lastlog, &arp_curpps, arp_maxpps)) \ 141 log((pri), "arp: " __VA_ARGS__); \ 142 } while (0) 143 144 145 static void arp_init(void); 146 static void arpintr(struct mbuf *); 147 static void arptimer(void *); 148 #ifdef INET 149 static void in_arpinput(struct mbuf *); 150 #endif 151 152 static void arp_check_update_lle(struct arphdr *ah, struct in_addr isaddr, 153 struct ifnet *ifp, int bridged, struct llentry *la); 154 static void arp_mark_lle_reachable(struct llentry *la); 155 static void arp_iflladdr(void *arg __unused, struct ifnet *ifp); 156 157 static eventhandler_tag iflladdr_tag; 158 159 static const struct netisr_handler arp_nh = { 160 .nh_name = "arp", 161 .nh_handler = arpintr, 162 .nh_proto = NETISR_ARP, 163 .nh_policy = NETISR_POLICY_SOURCE, 164 }; 165 166 /* 167 * Timeout routine. Age arp_tab entries periodically. 168 */ 169 static void 170 arptimer(void *arg) 171 { 172 struct llentry *lle = (struct llentry *)arg; 173 struct ifnet *ifp; 174 int r_skip_req; 175 176 if (lle->la_flags & LLE_STATIC) { 177 return; 178 } 179 LLE_WLOCK(lle); 180 if (callout_pending(&lle->lle_timer)) { 181 /* 182 * Here we are a bit odd here in the treatment of 183 * active/pending. If the pending bit is set, it got 184 * rescheduled before I ran. The active 185 * bit we ignore, since if it was stopped 186 * in ll_tablefree() and was currently running 187 * it would have return 0 so the code would 188 * not have deleted it since the callout could 189 * not be stopped so we want to go through 190 * with the delete here now. If the callout 191 * was restarted, the pending bit will be back on and 192 * we just want to bail since the callout_reset would 193 * return 1 and our reference would have been removed 194 * by arpresolve() below. 195 */ 196 LLE_WUNLOCK(lle); 197 return; 198 } 199 ifp = lle->lle_tbl->llt_ifp; 200 CURVNET_SET(ifp->if_vnet); 201 202 switch (lle->ln_state) { 203 case ARP_LLINFO_REACHABLE: 204 205 /* 206 * Expiration time is approaching. 207 * Let's try to refresh entry if it is still 208 * in use. 209 * 210 * Set r_skip_req to get feedback from 211 * fast path. Change state and re-schedule 212 * ourselves. 213 */ 214 LLE_REQ_LOCK(lle); 215 lle->r_skip_req = 1; 216 LLE_REQ_UNLOCK(lle); 217 lle->ln_state = ARP_LLINFO_VERIFY; 218 callout_schedule(&lle->lle_timer, hz * V_arpt_rexmit); 219 LLE_WUNLOCK(lle); 220 CURVNET_RESTORE(); 221 return; 222 case ARP_LLINFO_VERIFY: 223 LLE_REQ_LOCK(lle); 224 r_skip_req = lle->r_skip_req; 225 LLE_REQ_UNLOCK(lle); 226 227 if (r_skip_req == 0 && lle->la_preempt > 0) { 228 /* Entry was used, issue refresh request */ 229 struct in_addr dst; 230 dst = lle->r_l3addr.addr4; 231 lle->la_preempt--; 232 callout_schedule(&lle->lle_timer, hz * V_arpt_rexmit); 233 LLE_WUNLOCK(lle); 234 arprequest(ifp, NULL, &dst, NULL); 235 CURVNET_RESTORE(); 236 return; 237 } 238 /* Nothing happened. Reschedule if not too late */ 239 if (lle->la_expire > time_uptime) { 240 callout_schedule(&lle->lle_timer, hz * V_arpt_rexmit); 241 LLE_WUNLOCK(lle); 242 CURVNET_RESTORE(); 243 return; 244 } 245 break; 246 case ARP_LLINFO_INCOMPLETE: 247 case ARP_LLINFO_DELETED: 248 break; 249 } 250 251 if ((lle->la_flags & LLE_DELETED) == 0) { 252 int evt; 253 254 if (lle->la_flags & LLE_VALID) 255 evt = LLENTRY_EXPIRED; 256 else 257 evt = LLENTRY_TIMEDOUT; 258 EVENTHANDLER_INVOKE(lle_event, lle, evt); 259 } 260 261 callout_stop(&lle->lle_timer); 262 263 /* XXX: LOR avoidance. We still have ref on lle. */ 264 LLE_WUNLOCK(lle); 265 IF_AFDATA_LOCK(ifp); 266 LLE_WLOCK(lle); 267 268 /* Guard against race with other llentry_free(). */ 269 if (lle->la_flags & LLE_LINKED) { 270 LLE_REMREF(lle); 271 lltable_unlink_entry(lle->lle_tbl, lle); 272 } 273 IF_AFDATA_UNLOCK(ifp); 274 275 size_t pkts_dropped = llentry_free(lle); 276 277 ARPSTAT_ADD(dropped, pkts_dropped); 278 ARPSTAT_INC(timeouts); 279 280 CURVNET_RESTORE(); 281 } 282 283 /* 284 * Broadcast an ARP request. Caller specifies: 285 * - arp header source ip address 286 * - arp header target ip address 287 * - arp header source ethernet address 288 */ 289 void 290 arprequest(struct ifnet *ifp, const struct in_addr *sip, 291 const struct in_addr *tip, u_char *enaddr) 292 { 293 struct mbuf *m; 294 struct arphdr *ah; 295 struct sockaddr sa; 296 u_char *carpaddr = NULL; 297 298 if (sip == NULL) { 299 /* 300 * The caller did not supply a source address, try to find 301 * a compatible one among those assigned to this interface. 302 */ 303 struct ifaddr *ifa; 304 305 IF_ADDR_RLOCK(ifp); 306 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) { 307 if (ifa->ifa_addr->sa_family != AF_INET) 308 continue; 309 310 if (ifa->ifa_carp) { 311 if ((*carp_iamatch_p)(ifa, &carpaddr) == 0) 312 continue; 313 sip = &IA_SIN(ifa)->sin_addr; 314 } else { 315 carpaddr = NULL; 316 sip = &IA_SIN(ifa)->sin_addr; 317 } 318 319 if (0 == ((sip->s_addr ^ tip->s_addr) & 320 IA_MASKSIN(ifa)->sin_addr.s_addr)) 321 break; /* found it. */ 322 } 323 IF_ADDR_RUNLOCK(ifp); 324 if (sip == NULL) { 325 printf("%s: cannot find matching address\n", __func__); 326 return; 327 } 328 } 329 if (enaddr == NULL) 330 enaddr = carpaddr ? carpaddr : (u_char *)IF_LLADDR(ifp); 331 332 if ((m = m_gethdr(M_NOWAIT, MT_DATA)) == NULL) 333 return; 334 m->m_len = sizeof(*ah) + 2 * sizeof(struct in_addr) + 335 2 * ifp->if_addrlen; 336 m->m_pkthdr.len = m->m_len; 337 M_ALIGN(m, m->m_len); 338 ah = mtod(m, struct arphdr *); 339 bzero((caddr_t)ah, m->m_len); 340 #ifdef MAC 341 mac_netinet_arp_send(ifp, m); 342 #endif 343 ah->ar_pro = htons(ETHERTYPE_IP); 344 ah->ar_hln = ifp->if_addrlen; /* hardware address length */ 345 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 346 ah->ar_op = htons(ARPOP_REQUEST); 347 bcopy(enaddr, ar_sha(ah), ah->ar_hln); 348 bcopy(sip, ar_spa(ah), ah->ar_pln); 349 bcopy(tip, ar_tpa(ah), ah->ar_pln); 350 sa.sa_family = AF_ARP; 351 sa.sa_len = 2; 352 m->m_flags |= M_BCAST; 353 m_clrprotoflags(m); /* Avoid confusing lower layers. */ 354 (*ifp->if_output)(ifp, m, &sa, NULL); 355 ARPSTAT_INC(txrequests); 356 } 357 358 /* 359 * Resolve an IP address into an ethernet address - heavy version. 360 * Used internally by arpresolve(). 361 * We have already checked than we can't use existing lle without 362 * modification so we have to acquire LLE_EXCLUSIVE lle lock. 363 * 364 * On success, desten and flags are filled in and the function returns 0; 365 * If the packet must be held pending resolution, we return EWOULDBLOCK 366 * On other errors, we return the corresponding error code. 367 * Note that m_freem() handles NULL. 368 */ 369 static int 370 arpresolve_full(struct ifnet *ifp, int is_gw, int create, struct mbuf *m, 371 const struct sockaddr *dst, u_char *desten, uint32_t *pflags) 372 { 373 struct llentry *la = NULL, *la_tmp; 374 struct mbuf *curr = NULL; 375 struct mbuf *next = NULL; 376 int error, renew; 377 378 if (pflags != NULL) 379 *pflags = 0; 380 381 if (create == 0) { 382 IF_AFDATA_RLOCK(ifp); 383 la = lla_lookup(LLTABLE(ifp), LLE_EXCLUSIVE, dst); 384 IF_AFDATA_RUNLOCK(ifp); 385 } 386 if (la == NULL && (ifp->if_flags & (IFF_NOARP | IFF_STATICARP)) == 0) { 387 la = lltable_alloc_entry(LLTABLE(ifp), 0, dst); 388 if (la == NULL) { 389 log(LOG_DEBUG, 390 "arpresolve: can't allocate llinfo for %s on %s\n", 391 inet_ntoa(SIN(dst)->sin_addr), if_name(ifp)); 392 m_freem(m); 393 return (EINVAL); 394 } 395 396 IF_AFDATA_WLOCK(ifp); 397 LLE_WLOCK(la); 398 la_tmp = lla_lookup(LLTABLE(ifp), LLE_EXCLUSIVE, dst); 399 /* Prefer ANY existing lle over newly-created one */ 400 if (la_tmp == NULL) 401 lltable_link_entry(LLTABLE(ifp), la); 402 IF_AFDATA_WUNLOCK(ifp); 403 if (la_tmp != NULL) { 404 lltable_free_entry(LLTABLE(ifp), la); 405 la = la_tmp; 406 } 407 } 408 if (la == NULL) { 409 m_freem(m); 410 return (EINVAL); 411 } 412 413 if ((la->la_flags & LLE_VALID) && 414 ((la->la_flags & LLE_STATIC) || la->la_expire > time_uptime)) { 415 bcopy(&la->ll_addr, desten, ifp->if_addrlen); 416 417 /* Check if we have feedback request from arptimer() */ 418 if (la->r_skip_req != 0) { 419 LLE_REQ_LOCK(la); 420 la->r_skip_req = 0; /* Notify that entry was used */ 421 LLE_REQ_UNLOCK(la); 422 } 423 if (pflags != NULL) 424 *pflags = la->la_flags & (LLE_VALID|LLE_IFADDR); 425 LLE_WUNLOCK(la); 426 return (0); 427 } 428 429 renew = (la->la_asked == 0 || la->la_expire != time_uptime); 430 /* 431 * There is an arptab entry, but no ethernet address 432 * response yet. Add the mbuf to the list, dropping 433 * the oldest packet if we have exceeded the system 434 * setting. 435 */ 436 if (m != NULL) { 437 if (la->la_numheld >= V_arp_maxhold) { 438 if (la->la_hold != NULL) { 439 next = la->la_hold->m_nextpkt; 440 m_freem(la->la_hold); 441 la->la_hold = next; 442 la->la_numheld--; 443 ARPSTAT_INC(dropped); 444 } 445 } 446 if (la->la_hold != NULL) { 447 curr = la->la_hold; 448 while (curr->m_nextpkt != NULL) 449 curr = curr->m_nextpkt; 450 curr->m_nextpkt = m; 451 } else 452 la->la_hold = m; 453 la->la_numheld++; 454 } 455 /* 456 * Return EWOULDBLOCK if we have tried less than arp_maxtries. It 457 * will be masked by ether_output(). Return EHOSTDOWN/EHOSTUNREACH 458 * if we have already sent arp_maxtries ARP requests. Retransmit the 459 * ARP request, but not faster than one request per second. 460 */ 461 if (la->la_asked < V_arp_maxtries) 462 error = EWOULDBLOCK; /* First request. */ 463 else 464 error = is_gw != 0 ? EHOSTUNREACH : EHOSTDOWN; 465 466 if (renew) { 467 int canceled; 468 469 LLE_ADDREF(la); 470 la->la_expire = time_uptime; 471 canceled = callout_reset(&la->lle_timer, hz * V_arpt_down, 472 arptimer, la); 473 if (canceled) 474 LLE_REMREF(la); 475 la->la_asked++; 476 LLE_WUNLOCK(la); 477 arprequest(ifp, NULL, &SIN(dst)->sin_addr, NULL); 478 return (error); 479 } 480 481 LLE_WUNLOCK(la); 482 return (error); 483 } 484 485 /* 486 * Resolve an IP address into an ethernet address. 487 * On input: 488 * ifp is the interface we use 489 * is_gw != 0 if @dst represents gateway to some destination 490 * m is the mbuf. May be NULL if we don't have a packet. 491 * dst is the next hop, 492 * desten is the storage to put LL address. 493 * flags returns subset of lle flags: LLE_VALID | LLE_IFADDR 494 * 495 * On success, desten and flags are filled in and the function returns 0; 496 * If the packet must be held pending resolution, we return EWOULDBLOCK 497 * On other errors, we return the corresponding error code. 498 * Note that m_freem() handles NULL. 499 */ 500 int 501 arpresolve(struct ifnet *ifp, int is_gw, struct mbuf *m, 502 const struct sockaddr *dst, u_char *desten, uint32_t *pflags) 503 { 504 struct llentry *la = 0; 505 506 if (pflags != NULL) 507 *pflags = 0; 508 509 if (m != NULL) { 510 if (m->m_flags & M_BCAST) { 511 /* broadcast */ 512 (void)memcpy(desten, 513 ifp->if_broadcastaddr, ifp->if_addrlen); 514 return (0); 515 } 516 if (m->m_flags & M_MCAST) { 517 /* multicast */ 518 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); 519 return (0); 520 } 521 } 522 523 IF_AFDATA_RLOCK(ifp); 524 la = lla_lookup(LLTABLE(ifp), LLE_UNLOCKED, dst); 525 if (la != NULL && (la->r_flags & RLLE_VALID) != 0) { 526 /* Entry found, let's copy lle info */ 527 bcopy(&la->ll_addr, desten, ifp->if_addrlen); 528 if (pflags != NULL) 529 *pflags = LLE_VALID | (la->r_flags & RLLE_IFADDR); 530 /* Check if we have feedback request from arptimer() */ 531 if (la->r_skip_req != 0) { 532 LLE_REQ_LOCK(la); 533 la->r_skip_req = 0; /* Notify that entry was used */ 534 LLE_REQ_UNLOCK(la); 535 } 536 IF_AFDATA_RUNLOCK(ifp); 537 return (0); 538 } 539 IF_AFDATA_RUNLOCK(ifp); 540 541 return (arpresolve_full(ifp, is_gw, 1, m, dst, desten, pflags)); 542 } 543 544 /* 545 * Common length and type checks are done here, 546 * then the protocol-specific routine is called. 547 */ 548 static void 549 arpintr(struct mbuf *m) 550 { 551 struct arphdr *ar; 552 struct ifnet *ifp; 553 char *layer; 554 int hlen; 555 556 ifp = m->m_pkthdr.rcvif; 557 558 if (m->m_len < sizeof(struct arphdr) && 559 ((m = m_pullup(m, sizeof(struct arphdr))) == NULL)) { 560 ARP_LOG(LOG_NOTICE, "packet with short header received on %s\n", 561 if_name(ifp)); 562 return; 563 } 564 ar = mtod(m, struct arphdr *); 565 566 /* Check if length is sufficient */ 567 if (m->m_len < arphdr_len(ar)) { 568 m = m_pullup(m, arphdr_len(ar)); 569 if (m == NULL) { 570 ARP_LOG(LOG_NOTICE, "short packet received on %s\n", 571 if_name(ifp)); 572 return; 573 } 574 ar = mtod(m, struct arphdr *); 575 } 576 577 hlen = 0; 578 layer = ""; 579 switch (ntohs(ar->ar_hrd)) { 580 case ARPHRD_ETHER: 581 hlen = ETHER_ADDR_LEN; /* RFC 826 */ 582 layer = "ethernet"; 583 break; 584 case ARPHRD_IEEE802: 585 hlen = 6; /* RFC 1390, FDDI_ADDR_LEN */ 586 layer = "fddi"; 587 break; 588 case ARPHRD_ARCNET: 589 hlen = 1; /* RFC 1201, ARC_ADDR_LEN */ 590 layer = "arcnet"; 591 break; 592 case ARPHRD_INFINIBAND: 593 hlen = 20; /* RFC 4391, INFINIBAND_ALEN */ 594 layer = "infiniband"; 595 break; 596 case ARPHRD_IEEE1394: 597 hlen = 0; /* SHALL be 16 */ /* RFC 2734 */ 598 layer = "firewire"; 599 600 /* 601 * Restrict too long harware addresses. 602 * Currently we are capable of handling 20-byte 603 * addresses ( sizeof(lle->ll_addr) ) 604 */ 605 if (ar->ar_hln >= 20) 606 hlen = 16; 607 break; 608 default: 609 ARP_LOG(LOG_NOTICE, 610 "packet with unknown harware format 0x%02d received on %s\n", 611 ntohs(ar->ar_hrd), if_name(ifp)); 612 m_freem(m); 613 return; 614 } 615 616 if (hlen != 0 && hlen != ar->ar_hln) { 617 ARP_LOG(LOG_NOTICE, 618 "packet with invalid %s address length %d received on %s\n", 619 layer, ar->ar_hln, if_name(ifp)); 620 m_freem(m); 621 return; 622 } 623 624 ARPSTAT_INC(received); 625 switch (ntohs(ar->ar_pro)) { 626 #ifdef INET 627 case ETHERTYPE_IP: 628 in_arpinput(m); 629 return; 630 #endif 631 } 632 m_freem(m); 633 } 634 635 #ifdef INET 636 /* 637 * ARP for Internet protocols on 10 Mb/s Ethernet. 638 * Algorithm is that given in RFC 826. 639 * In addition, a sanity check is performed on the sender 640 * protocol address, to catch impersonators. 641 * We no longer handle negotiations for use of trailer protocol: 642 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 643 * along with IP replies if we wanted trailers sent to us, 644 * and also sent them in response to IP replies. 645 * This allowed either end to announce the desire to receive 646 * trailer packets. 647 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 648 * but formerly didn't normally send requests. 649 */ 650 static int log_arp_wrong_iface = 1; 651 static int log_arp_movements = 1; 652 static int log_arp_permanent_modify = 1; 653 static int allow_multicast = 0; 654 655 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW, 656 &log_arp_wrong_iface, 0, 657 "log arp packets arriving on the wrong interface"); 658 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_movements, CTLFLAG_RW, 659 &log_arp_movements, 0, 660 "log arp replies from MACs different than the one in the cache"); 661 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_permanent_modify, CTLFLAG_RW, 662 &log_arp_permanent_modify, 0, 663 "log arp replies from MACs different than the one in the permanent arp entry"); 664 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, allow_multicast, CTLFLAG_RW, 665 &allow_multicast, 0, "accept multicast addresses"); 666 667 static void 668 in_arpinput(struct mbuf *m) 669 { 670 struct rm_priotracker in_ifa_tracker; 671 struct arphdr *ah; 672 struct ifnet *ifp = m->m_pkthdr.rcvif; 673 struct llentry *la = NULL, *la_tmp; 674 struct rtentry *rt; 675 struct ifaddr *ifa; 676 struct in_ifaddr *ia; 677 struct sockaddr sa; 678 struct in_addr isaddr, itaddr, myaddr; 679 u_int8_t *enaddr = NULL; 680 int op; 681 int bridged = 0, is_bridge = 0; 682 int carped; 683 struct sockaddr_in sin; 684 struct sockaddr *dst; 685 sin.sin_len = sizeof(struct sockaddr_in); 686 sin.sin_family = AF_INET; 687 sin.sin_addr.s_addr = 0; 688 689 if (ifp->if_bridge) 690 bridged = 1; 691 if (ifp->if_type == IFT_BRIDGE) 692 is_bridge = 1; 693 694 /* 695 * We already have checked that mbuf contains enough contiguous data 696 * to hold entire arp message according to the arp header. 697 */ 698 ah = mtod(m, struct arphdr *); 699 700 /* 701 * ARP is only for IPv4 so we can reject packets with 702 * a protocol length not equal to an IPv4 address. 703 */ 704 if (ah->ar_pln != sizeof(struct in_addr)) { 705 ARP_LOG(LOG_NOTICE, "requested protocol length != %zu\n", 706 sizeof(struct in_addr)); 707 goto drop; 708 } 709 710 if (allow_multicast == 0 && ETHER_IS_MULTICAST(ar_sha(ah))) { 711 ARP_LOG(LOG_NOTICE, "%*D is multicast\n", 712 ifp->if_addrlen, (u_char *)ar_sha(ah), ":"); 713 goto drop; 714 } 715 716 op = ntohs(ah->ar_op); 717 (void)memcpy(&isaddr, ar_spa(ah), sizeof (isaddr)); 718 (void)memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr)); 719 720 if (op == ARPOP_REPLY) 721 ARPSTAT_INC(rxreplies); 722 723 /* 724 * For a bridge, we want to check the address irrespective 725 * of the receive interface. (This will change slightly 726 * when we have clusters of interfaces). 727 */ 728 IN_IFADDR_RLOCK(&in_ifa_tracker); 729 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) { 730 if (((bridged && ia->ia_ifp->if_bridge == ifp->if_bridge) || 731 ia->ia_ifp == ifp) && 732 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr && 733 (ia->ia_ifa.ifa_carp == NULL || 734 (*carp_iamatch_p)(&ia->ia_ifa, &enaddr))) { 735 ifa_ref(&ia->ia_ifa); 736 IN_IFADDR_RUNLOCK(&in_ifa_tracker); 737 goto match; 738 } 739 } 740 LIST_FOREACH(ia, INADDR_HASH(isaddr.s_addr), ia_hash) 741 if (((bridged && ia->ia_ifp->if_bridge == ifp->if_bridge) || 742 ia->ia_ifp == ifp) && 743 isaddr.s_addr == ia->ia_addr.sin_addr.s_addr) { 744 ifa_ref(&ia->ia_ifa); 745 IN_IFADDR_RUNLOCK(&in_ifa_tracker); 746 goto match; 747 } 748 749 #define BDG_MEMBER_MATCHES_ARP(addr, ifp, ia) \ 750 (ia->ia_ifp->if_bridge == ifp->if_softc && \ 751 !bcmp(IF_LLADDR(ia->ia_ifp), IF_LLADDR(ifp), ifp->if_addrlen) && \ 752 addr == ia->ia_addr.sin_addr.s_addr) 753 /* 754 * Check the case when bridge shares its MAC address with 755 * some of its children, so packets are claimed by bridge 756 * itself (bridge_input() does it first), but they are really 757 * meant to be destined to the bridge member. 758 */ 759 if (is_bridge) { 760 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) { 761 if (BDG_MEMBER_MATCHES_ARP(itaddr.s_addr, ifp, ia)) { 762 ifa_ref(&ia->ia_ifa); 763 ifp = ia->ia_ifp; 764 IN_IFADDR_RUNLOCK(&in_ifa_tracker); 765 goto match; 766 } 767 } 768 } 769 #undef BDG_MEMBER_MATCHES_ARP 770 IN_IFADDR_RUNLOCK(&in_ifa_tracker); 771 772 /* 773 * No match, use the first inet address on the receive interface 774 * as a dummy address for the rest of the function. 775 */ 776 IF_ADDR_RLOCK(ifp); 777 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) 778 if (ifa->ifa_addr->sa_family == AF_INET && 779 (ifa->ifa_carp == NULL || 780 (*carp_iamatch_p)(ifa, &enaddr))) { 781 ia = ifatoia(ifa); 782 ifa_ref(ifa); 783 IF_ADDR_RUNLOCK(ifp); 784 goto match; 785 } 786 IF_ADDR_RUNLOCK(ifp); 787 788 /* 789 * If bridging, fall back to using any inet address. 790 */ 791 IN_IFADDR_RLOCK(&in_ifa_tracker); 792 if (!bridged || (ia = TAILQ_FIRST(&V_in_ifaddrhead)) == NULL) { 793 IN_IFADDR_RUNLOCK(&in_ifa_tracker); 794 goto drop; 795 } 796 ifa_ref(&ia->ia_ifa); 797 IN_IFADDR_RUNLOCK(&in_ifa_tracker); 798 match: 799 if (!enaddr) 800 enaddr = (u_int8_t *)IF_LLADDR(ifp); 801 carped = (ia->ia_ifa.ifa_carp != NULL); 802 myaddr = ia->ia_addr.sin_addr; 803 ifa_free(&ia->ia_ifa); 804 if (!bcmp(ar_sha(ah), enaddr, ifp->if_addrlen)) 805 goto drop; /* it's from me, ignore it. */ 806 if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) { 807 ARP_LOG(LOG_NOTICE, "link address is broadcast for IP address " 808 "%s!\n", inet_ntoa(isaddr)); 809 goto drop; 810 } 811 812 if (ifp->if_addrlen != ah->ar_hln) { 813 ARP_LOG(LOG_WARNING, "from %*D: addr len: new %d, " 814 "i/f %d (ignored)\n", ifp->if_addrlen, 815 (u_char *) ar_sha(ah), ":", ah->ar_hln, 816 ifp->if_addrlen); 817 goto drop; 818 } 819 820 /* 821 * Warn if another host is using the same IP address, but only if the 822 * IP address isn't 0.0.0.0, which is used for DHCP only, in which 823 * case we suppress the warning to avoid false positive complaints of 824 * potential misconfiguration. 825 */ 826 if (!bridged && !carped && isaddr.s_addr == myaddr.s_addr && 827 myaddr.s_addr != 0) { 828 ARP_LOG(LOG_ERR, "%*D is using my IP address %s on %s!\n", 829 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 830 inet_ntoa(isaddr), ifp->if_xname); 831 itaddr = myaddr; 832 ARPSTAT_INC(dupips); 833 goto reply; 834 } 835 if (ifp->if_flags & IFF_STATICARP) 836 goto reply; 837 838 bzero(&sin, sizeof(sin)); 839 sin.sin_len = sizeof(struct sockaddr_in); 840 sin.sin_family = AF_INET; 841 sin.sin_addr = isaddr; 842 dst = (struct sockaddr *)&sin; 843 IF_AFDATA_RLOCK(ifp); 844 la = lla_lookup(LLTABLE(ifp), LLE_EXCLUSIVE, dst); 845 IF_AFDATA_RUNLOCK(ifp); 846 if (la != NULL) 847 arp_check_update_lle(ah, isaddr, ifp, bridged, la); 848 else if (itaddr.s_addr == myaddr.s_addr) { 849 /* 850 * Reply to our address, but no lle exists yet. 851 * do we really have to create an entry? 852 */ 853 la = lltable_alloc_entry(LLTABLE(ifp), 0, dst); 854 if (la == NULL) 855 goto drop; 856 lltable_set_entry_addr(ifp, la, ar_sha(ah)); 857 858 IF_AFDATA_WLOCK(ifp); 859 LLE_WLOCK(la); 860 la_tmp = lla_lookup(LLTABLE(ifp), LLE_EXCLUSIVE, dst); 861 862 /* 863 * Check if lle still does not exists. 864 * If it does, that means that we either 865 * 1) have configured it explicitly, via 866 * 1a) 'arp -s' static entry or 867 * 1b) interface address static record 868 * or 869 * 2) it was the result of sending first packet to-host 870 * or 871 * 3) it was another arp reply packet we handled in 872 * different thread. 873 * 874 * In all cases except 3) we definitely need to prefer 875 * existing lle. For the sake of simplicity, prefer any 876 * existing lle over newly-create one. 877 */ 878 if (la_tmp == NULL) 879 lltable_link_entry(LLTABLE(ifp), la); 880 IF_AFDATA_WUNLOCK(ifp); 881 882 if (la_tmp == NULL) { 883 arp_mark_lle_reachable(la); 884 LLE_WUNLOCK(la); 885 } else { 886 /* Free newly-create entry and handle packet */ 887 lltable_free_entry(LLTABLE(ifp), la); 888 la = la_tmp; 889 la_tmp = NULL; 890 arp_check_update_lle(ah, isaddr, ifp, bridged, la); 891 /* arp_check_update_lle() returns @la unlocked */ 892 } 893 la = NULL; 894 } 895 reply: 896 if (op != ARPOP_REQUEST) 897 goto drop; 898 ARPSTAT_INC(rxrequests); 899 900 if (itaddr.s_addr == myaddr.s_addr) { 901 /* Shortcut.. the receiving interface is the target. */ 902 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 903 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln); 904 } else { 905 struct llentry *lle = NULL; 906 907 sin.sin_addr = itaddr; 908 IF_AFDATA_RLOCK(ifp); 909 lle = lla_lookup(LLTABLE(ifp), 0, (struct sockaddr *)&sin); 910 IF_AFDATA_RUNLOCK(ifp); 911 912 if ((lle != NULL) && (lle->la_flags & LLE_PUB)) { 913 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 914 (void)memcpy(ar_sha(ah), &lle->ll_addr, ah->ar_hln); 915 LLE_RUNLOCK(lle); 916 } else { 917 918 if (lle != NULL) 919 LLE_RUNLOCK(lle); 920 921 if (!V_arp_proxyall) 922 goto drop; 923 924 sin.sin_addr = itaddr; 925 /* XXX MRT use table 0 for arp reply */ 926 rt = in_rtalloc1((struct sockaddr *)&sin, 0, 0UL, 0); 927 if (!rt) 928 goto drop; 929 930 /* 931 * Don't send proxies for nodes on the same interface 932 * as this one came out of, or we'll get into a fight 933 * over who claims what Ether address. 934 */ 935 if (!rt->rt_ifp || rt->rt_ifp == ifp) { 936 RTFREE_LOCKED(rt); 937 goto drop; 938 } 939 RTFREE_LOCKED(rt); 940 941 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 942 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln); 943 944 /* 945 * Also check that the node which sent the ARP packet 946 * is on the interface we expect it to be on. This 947 * avoids ARP chaos if an interface is connected to the 948 * wrong network. 949 */ 950 sin.sin_addr = isaddr; 951 952 /* XXX MRT use table 0 for arp checks */ 953 rt = in_rtalloc1((struct sockaddr *)&sin, 0, 0UL, 0); 954 if (!rt) 955 goto drop; 956 if (rt->rt_ifp != ifp) { 957 ARP_LOG(LOG_INFO, "proxy: ignoring request" 958 " from %s via %s, expecting %s\n", 959 inet_ntoa(isaddr), ifp->if_xname, 960 rt->rt_ifp->if_xname); 961 RTFREE_LOCKED(rt); 962 goto drop; 963 } 964 RTFREE_LOCKED(rt); 965 966 #ifdef DEBUG_PROXY 967 printf("arp: proxying for %s\n", inet_ntoa(itaddr)); 968 #endif 969 } 970 } 971 972 if (itaddr.s_addr == myaddr.s_addr && 973 IN_LINKLOCAL(ntohl(itaddr.s_addr))) { 974 /* RFC 3927 link-local IPv4; always reply by broadcast. */ 975 #ifdef DEBUG_LINKLOCAL 976 printf("arp: sending reply for link-local addr %s\n", 977 inet_ntoa(itaddr)); 978 #endif 979 m->m_flags |= M_BCAST; 980 m->m_flags &= ~M_MCAST; 981 } else { 982 /* default behaviour; never reply by broadcast. */ 983 m->m_flags &= ~(M_BCAST|M_MCAST); 984 } 985 (void)memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln); 986 (void)memcpy(ar_spa(ah), &itaddr, ah->ar_pln); 987 ah->ar_op = htons(ARPOP_REPLY); 988 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 989 m->m_len = sizeof(*ah) + (2 * ah->ar_pln) + (2 * ah->ar_hln); 990 m->m_pkthdr.len = m->m_len; 991 m->m_pkthdr.rcvif = NULL; 992 sa.sa_family = AF_ARP; 993 sa.sa_len = 2; 994 m_clrprotoflags(m); /* Avoid confusing lower layers. */ 995 (*ifp->if_output)(ifp, m, &sa, NULL); 996 ARPSTAT_INC(txreplies); 997 return; 998 999 drop: 1000 m_freem(m); 1001 } 1002 #endif 1003 1004 /* 1005 * Checks received arp data against existing @la. 1006 * Updates lle state/performs notification if necessary. 1007 */ 1008 static void 1009 arp_check_update_lle(struct arphdr *ah, struct in_addr isaddr, struct ifnet *ifp, 1010 int bridged, struct llentry *la) 1011 { 1012 struct sockaddr sa; 1013 struct mbuf *m_hold, *m_hold_next; 1014 1015 LLE_WLOCK_ASSERT(la); 1016 1017 /* the following is not an error when doing bridging */ 1018 if (!bridged && la->lle_tbl->llt_ifp != ifp) { 1019 if (log_arp_wrong_iface) 1020 ARP_LOG(LOG_WARNING, "%s is on %s " 1021 "but got reply from %*D on %s\n", 1022 inet_ntoa(isaddr), 1023 la->lle_tbl->llt_ifp->if_xname, 1024 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 1025 ifp->if_xname); 1026 LLE_WUNLOCK(la); 1027 return; 1028 } 1029 if ((la->la_flags & LLE_VALID) && 1030 bcmp(ar_sha(ah), &la->ll_addr, ifp->if_addrlen)) { 1031 if (la->la_flags & LLE_STATIC) { 1032 LLE_WUNLOCK(la); 1033 if (log_arp_permanent_modify) 1034 ARP_LOG(LOG_ERR, 1035 "%*D attempts to modify " 1036 "permanent entry for %s on %s\n", 1037 ifp->if_addrlen, 1038 (u_char *)ar_sha(ah), ":", 1039 inet_ntoa(isaddr), ifp->if_xname); 1040 return; 1041 } 1042 if (log_arp_movements) { 1043 ARP_LOG(LOG_INFO, "%s moved from %*D " 1044 "to %*D on %s\n", 1045 inet_ntoa(isaddr), 1046 ifp->if_addrlen, 1047 (u_char *)&la->ll_addr, ":", 1048 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 1049 ifp->if_xname); 1050 } 1051 } 1052 1053 /* Check if something has changed */ 1054 if (memcmp(&la->ll_addr, ar_sha(ah), ifp->if_addrlen) != 0 || 1055 (la->la_flags & LLE_VALID) == 0) { 1056 /* Perform real LLE update */ 1057 /* use afdata WLOCK to update fields */ 1058 LLE_ADDREF(la); 1059 LLE_WUNLOCK(la); 1060 IF_AFDATA_WLOCK(ifp); 1061 LLE_WLOCK(la); 1062 1063 /* 1064 * Since we droppped LLE lock, other thread might have deleted 1065 * this lle. Check and return 1066 */ 1067 if ((la->la_flags & LLE_DELETED) != 0) { 1068 IF_AFDATA_WUNLOCK(ifp); 1069 LLE_FREE_LOCKED(la); 1070 return; 1071 } 1072 1073 /* Update data */ 1074 lltable_set_entry_addr(ifp, la, ar_sha(ah)); 1075 1076 IF_AFDATA_WUNLOCK(ifp); 1077 LLE_REMREF(la); 1078 1079 /* Clear fast path feedback request if set */ 1080 la->r_skip_req = 0; 1081 } 1082 1083 arp_mark_lle_reachable(la); 1084 1085 /* 1086 * The packets are all freed within the call to the output 1087 * routine. 1088 * 1089 * NB: The lock MUST be released before the call to the 1090 * output routine. 1091 */ 1092 if (la->la_hold != NULL) { 1093 m_hold = la->la_hold; 1094 la->la_hold = NULL; 1095 la->la_numheld = 0; 1096 lltable_fill_sa_entry(la, &sa); 1097 LLE_WUNLOCK(la); 1098 for (; m_hold != NULL; m_hold = m_hold_next) { 1099 m_hold_next = m_hold->m_nextpkt; 1100 m_hold->m_nextpkt = NULL; 1101 /* Avoid confusing lower layers. */ 1102 m_clrprotoflags(m_hold); 1103 (*ifp->if_output)(ifp, m_hold, &sa, NULL); 1104 } 1105 } else 1106 LLE_WUNLOCK(la); 1107 } 1108 1109 static void 1110 arp_mark_lle_reachable(struct llentry *la) 1111 { 1112 int canceled, wtime; 1113 1114 LLE_WLOCK_ASSERT(la); 1115 1116 la->ln_state = ARP_LLINFO_REACHABLE; 1117 EVENTHANDLER_INVOKE(lle_event, la, LLENTRY_RESOLVED); 1118 1119 if (!(la->la_flags & LLE_STATIC)) { 1120 LLE_ADDREF(la); 1121 la->la_expire = time_uptime + V_arpt_keep; 1122 wtime = V_arpt_keep - V_arp_maxtries * V_arpt_rexmit; 1123 if (wtime < 0) 1124 wtime = V_arpt_keep; 1125 canceled = callout_reset(&la->lle_timer, 1126 hz * wtime, arptimer, la); 1127 if (canceled) 1128 LLE_REMREF(la); 1129 } 1130 la->la_asked = 0; 1131 la->la_preempt = V_arp_maxtries; 1132 } 1133 1134 /* 1135 * Add pernament link-layer record for given interface address. 1136 */ 1137 static __noinline void 1138 arp_add_ifa_lle(struct ifnet *ifp, const struct sockaddr *dst) 1139 { 1140 struct llentry *lle, *lle_tmp; 1141 1142 /* 1143 * Interface address LLE record is considered static 1144 * because kernel code relies on LLE_STATIC flag to check 1145 * if these entries can be rewriten by arp updates. 1146 */ 1147 lle = lltable_alloc_entry(LLTABLE(ifp), LLE_IFADDR | LLE_STATIC, dst); 1148 if (lle == NULL) { 1149 log(LOG_INFO, "arp_ifinit: cannot create arp " 1150 "entry for interface address\n"); 1151 return; 1152 } 1153 1154 IF_AFDATA_WLOCK(ifp); 1155 LLE_WLOCK(lle); 1156 /* Unlink any entry if exists */ 1157 lle_tmp = lla_lookup(LLTABLE(ifp), LLE_EXCLUSIVE, dst); 1158 if (lle_tmp != NULL) 1159 lltable_unlink_entry(LLTABLE(ifp), lle_tmp); 1160 1161 lltable_link_entry(LLTABLE(ifp), lle); 1162 IF_AFDATA_WUNLOCK(ifp); 1163 1164 if (lle_tmp != NULL) 1165 EVENTHANDLER_INVOKE(lle_event, lle_tmp, LLENTRY_EXPIRED); 1166 1167 EVENTHANDLER_INVOKE(lle_event, lle, LLENTRY_RESOLVED); 1168 LLE_WUNLOCK(lle); 1169 if (lle_tmp != NULL) 1170 lltable_free_entry(LLTABLE(ifp), lle_tmp); 1171 } 1172 1173 void 1174 arp_ifinit(struct ifnet *ifp, struct ifaddr *ifa) 1175 { 1176 const struct sockaddr_in *dst_in; 1177 const struct sockaddr *dst; 1178 1179 if (ifa->ifa_carp != NULL) 1180 return; 1181 1182 dst = ifa->ifa_addr; 1183 dst_in = (const struct sockaddr_in *)dst; 1184 1185 if (ntohl(dst_in->sin_addr.s_addr) == INADDR_ANY) 1186 return; 1187 arp_announce_ifaddr(ifp, dst_in->sin_addr, IF_LLADDR(ifp)); 1188 1189 arp_add_ifa_lle(ifp, dst); 1190 } 1191 1192 void 1193 arp_announce_ifaddr(struct ifnet *ifp, struct in_addr addr, u_char *enaddr) 1194 { 1195 1196 if (ntohl(addr.s_addr) != INADDR_ANY) 1197 arprequest(ifp, &addr, &addr, enaddr); 1198 } 1199 1200 /* 1201 * Sends gratuitous ARPs for each ifaddr to notify other 1202 * nodes about the address change. 1203 */ 1204 static __noinline void 1205 arp_handle_ifllchange(struct ifnet *ifp) 1206 { 1207 struct ifaddr *ifa; 1208 1209 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) { 1210 if (ifa->ifa_addr->sa_family == AF_INET) 1211 arp_ifinit(ifp, ifa); 1212 } 1213 } 1214 1215 /* 1216 * A handler for interface link layer address change event. 1217 */ 1218 static __noinline void 1219 arp_iflladdr(void *arg __unused, struct ifnet *ifp) 1220 { 1221 1222 if ((ifp->if_flags & IFF_UP) != 0) 1223 arp_handle_ifllchange(ifp); 1224 } 1225 1226 static void 1227 arp_init(void) 1228 { 1229 1230 netisr_register(&arp_nh); 1231 if (IS_DEFAULT_VNET(curvnet)) 1232 iflladdr_tag = EVENTHANDLER_REGISTER(iflladdr_event, 1233 arp_iflladdr, NULL, EVENTHANDLER_PRI_ANY); 1234 } 1235 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0); 1236