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_fib.h> 67 #include <netinet/in_var.h> 68 #include <net/if_llatbl.h> 69 #include <netinet/if_ether.h> 70 #ifdef INET 71 #include <netinet/ip_carp.h> 72 #endif 73 74 #include <security/mac/mac_framework.h> 75 76 #define SIN(s) ((const struct sockaddr_in *)(s)) 77 78 static struct timeval arp_lastlog; 79 static int arp_curpps; 80 static int arp_maxpps = 1; 81 82 /* Simple ARP state machine */ 83 enum arp_llinfo_state { 84 ARP_LLINFO_INCOMPLETE = 0, /* No LLE data */ 85 ARP_LLINFO_REACHABLE, /* LLE is valid */ 86 ARP_LLINFO_VERIFY, /* LLE is valid, need refresh */ 87 ARP_LLINFO_DELETED, /* LLE is deleted */ 88 }; 89 90 SYSCTL_DECL(_net_link_ether); 91 static SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, ""); 92 static SYSCTL_NODE(_net_link_ether, PF_ARP, arp, CTLFLAG_RW, 0, ""); 93 94 /* timer values */ 95 static VNET_DEFINE(int, arpt_keep) = (20*60); /* once resolved, good for 20 96 * minutes */ 97 static VNET_DEFINE(int, arp_maxtries) = 5; 98 static VNET_DEFINE(int, arp_proxyall) = 0; 99 static VNET_DEFINE(int, arpt_down) = 20; /* keep incomplete entries for 100 * 20 seconds */ 101 static VNET_DEFINE(int, arpt_rexmit) = 1; /* retransmit arp entries, sec*/ 102 VNET_PCPUSTAT_DEFINE(struct arpstat, arpstat); /* ARP statistics, see if_arp.h */ 103 VNET_PCPUSTAT_SYSINIT(arpstat); 104 105 #ifdef VIMAGE 106 VNET_PCPUSTAT_SYSUNINIT(arpstat); 107 #endif /* VIMAGE */ 108 109 static VNET_DEFINE(int, arp_maxhold) = 1; 110 111 #define V_arpt_keep VNET(arpt_keep) 112 #define V_arpt_down VNET(arpt_down) 113 #define V_arpt_rexmit VNET(arpt_rexmit) 114 #define V_arp_maxtries VNET(arp_maxtries) 115 #define V_arp_proxyall VNET(arp_proxyall) 116 #define V_arp_maxhold VNET(arp_maxhold) 117 118 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_VNET | CTLFLAG_RW, 119 &VNET_NAME(arpt_keep), 0, 120 "ARP entry lifetime in seconds"); 121 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_VNET | CTLFLAG_RW, 122 &VNET_NAME(arp_maxtries), 0, 123 "ARP resolution attempts before returning error"); 124 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_VNET | CTLFLAG_RW, 125 &VNET_NAME(arp_proxyall), 0, 126 "Enable proxy ARP for all suitable requests"); 127 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, wait, CTLFLAG_VNET | CTLFLAG_RW, 128 &VNET_NAME(arpt_down), 0, 129 "Incomplete ARP entry lifetime in seconds"); 130 SYSCTL_VNET_PCPUSTAT(_net_link_ether_arp, OID_AUTO, stats, struct arpstat, 131 arpstat, "ARP statistics (struct arpstat, net/if_arp.h)"); 132 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, maxhold, CTLFLAG_VNET | CTLFLAG_RW, 133 &VNET_NAME(arp_maxhold), 0, 134 "Number of packets to hold per ARP entry"); 135 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_log_per_second, 136 CTLFLAG_RW, &arp_maxpps, 0, 137 "Maximum number of remotely triggered ARP messages that can be " 138 "logged per second"); 139 140 #define ARP_LOG(pri, ...) do { \ 141 if (ppsratecheck(&arp_lastlog, &arp_curpps, arp_maxpps)) \ 142 log((pri), "arp: " __VA_ARGS__); \ 143 } while (0) 144 145 146 static void arp_init(void); 147 static void arpintr(struct mbuf *); 148 static void arptimer(void *); 149 #ifdef INET 150 static void in_arpinput(struct mbuf *); 151 #endif 152 153 static void arp_check_update_lle(struct arphdr *ah, struct in_addr isaddr, 154 struct ifnet *ifp, int bridged, struct llentry *la); 155 static void arp_mark_lle_reachable(struct llentry *la); 156 static void arp_iflladdr(void *arg __unused, struct ifnet *ifp); 157 158 static eventhandler_tag iflladdr_tag; 159 160 static const struct netisr_handler arp_nh = { 161 .nh_name = "arp", 162 .nh_handler = arpintr, 163 .nh_proto = NETISR_ARP, 164 .nh_policy = NETISR_POLICY_SOURCE, 165 }; 166 167 /* 168 * Timeout routine. Age arp_tab entries periodically. 169 */ 170 static void 171 arptimer(void *arg) 172 { 173 struct llentry *lle = (struct llentry *)arg; 174 struct ifnet *ifp; 175 int r_skip_req; 176 177 if (lle->la_flags & LLE_STATIC) { 178 return; 179 } 180 LLE_WLOCK(lle); 181 if (callout_pending(&lle->lle_timer)) { 182 /* 183 * Here we are a bit odd here in the treatment of 184 * active/pending. If the pending bit is set, it got 185 * rescheduled before I ran. The active 186 * bit we ignore, since if it was stopped 187 * in ll_tablefree() and was currently running 188 * it would have return 0 so the code would 189 * not have deleted it since the callout could 190 * not be stopped so we want to go through 191 * with the delete here now. If the callout 192 * was restarted, the pending bit will be back on and 193 * we just want to bail since the callout_reset would 194 * return 1 and our reference would have been removed 195 * by arpresolve() below. 196 */ 197 LLE_WUNLOCK(lle); 198 return; 199 } 200 ifp = lle->lle_tbl->llt_ifp; 201 CURVNET_SET(ifp->if_vnet); 202 203 switch (lle->ln_state) { 204 case ARP_LLINFO_REACHABLE: 205 206 /* 207 * Expiration time is approaching. 208 * Let's try to refresh entry if it is still 209 * in use. 210 * 211 * Set r_skip_req to get feedback from 212 * fast path. Change state and re-schedule 213 * ourselves. 214 */ 215 LLE_REQ_LOCK(lle); 216 lle->r_skip_req = 1; 217 LLE_REQ_UNLOCK(lle); 218 lle->ln_state = ARP_LLINFO_VERIFY; 219 callout_schedule(&lle->lle_timer, hz * V_arpt_rexmit); 220 LLE_WUNLOCK(lle); 221 CURVNET_RESTORE(); 222 return; 223 case ARP_LLINFO_VERIFY: 224 LLE_REQ_LOCK(lle); 225 r_skip_req = lle->r_skip_req; 226 LLE_REQ_UNLOCK(lle); 227 228 if (r_skip_req == 0 && lle->la_preempt > 0) { 229 /* Entry was used, issue refresh request */ 230 struct in_addr dst; 231 dst = lle->r_l3addr.addr4; 232 lle->la_preempt--; 233 callout_schedule(&lle->lle_timer, hz * V_arpt_rexmit); 234 LLE_WUNLOCK(lle); 235 arprequest(ifp, NULL, &dst, NULL); 236 CURVNET_RESTORE(); 237 return; 238 } 239 /* Nothing happened. Reschedule if not too late */ 240 if (lle->la_expire > time_uptime) { 241 callout_schedule(&lle->lle_timer, hz * V_arpt_rexmit); 242 LLE_WUNLOCK(lle); 243 CURVNET_RESTORE(); 244 return; 245 } 246 break; 247 case ARP_LLINFO_INCOMPLETE: 248 case ARP_LLINFO_DELETED: 249 break; 250 } 251 252 if ((lle->la_flags & LLE_DELETED) == 0) { 253 int evt; 254 255 if (lle->la_flags & LLE_VALID) 256 evt = LLENTRY_EXPIRED; 257 else 258 evt = LLENTRY_TIMEDOUT; 259 EVENTHANDLER_INVOKE(lle_event, lle, evt); 260 } 261 262 callout_stop(&lle->lle_timer); 263 264 /* XXX: LOR avoidance. We still have ref on lle. */ 265 LLE_WUNLOCK(lle); 266 IF_AFDATA_LOCK(ifp); 267 LLE_WLOCK(lle); 268 269 /* Guard against race with other llentry_free(). */ 270 if (lle->la_flags & LLE_LINKED) { 271 LLE_REMREF(lle); 272 lltable_unlink_entry(lle->lle_tbl, lle); 273 } 274 IF_AFDATA_UNLOCK(ifp); 275 276 size_t pkts_dropped = llentry_free(lle); 277 278 ARPSTAT_ADD(dropped, pkts_dropped); 279 ARPSTAT_INC(timeouts); 280 281 CURVNET_RESTORE(); 282 } 283 284 /* 285 * Stores link-layer header for @ifp in format suitable for if_output() 286 * into buffer @buf. Resulting header length is stored in @bufsize. 287 * 288 * Returns 0 on success. 289 */ 290 static int 291 arp_fillheader(struct ifnet *ifp, struct arphdr *ah, int bcast, u_char *buf, 292 size_t *bufsize) 293 { 294 struct if_encap_req ereq; 295 int error; 296 297 bzero(buf, *bufsize); 298 bzero(&ereq, sizeof(ereq)); 299 ereq.buf = buf; 300 ereq.bufsize = *bufsize; 301 ereq.rtype = IFENCAP_LL; 302 ereq.family = AF_ARP; 303 ereq.lladdr = ar_tha(ah); 304 ereq.hdata = (u_char *)ah; 305 if (bcast) 306 ereq.flags = IFENCAP_FLAG_BROADCAST; 307 error = ifp->if_requestencap(ifp, &ereq); 308 if (error == 0) 309 *bufsize = ereq.bufsize; 310 311 return (error); 312 } 313 314 315 /* 316 * Broadcast an ARP request. Caller specifies: 317 * - arp header source ip address 318 * - arp header target ip address 319 * - arp header source ethernet address 320 */ 321 void 322 arprequest(struct ifnet *ifp, const struct in_addr *sip, 323 const struct in_addr *tip, u_char *enaddr) 324 { 325 struct mbuf *m; 326 struct arphdr *ah; 327 struct sockaddr sa; 328 u_char *carpaddr = NULL; 329 uint8_t linkhdr[LLE_MAX_LINKHDR]; 330 size_t linkhdrsize; 331 struct route ro; 332 int error; 333 334 if (sip == NULL) { 335 /* 336 * The caller did not supply a source address, try to find 337 * a compatible one among those assigned to this interface. 338 */ 339 struct ifaddr *ifa; 340 341 IF_ADDR_RLOCK(ifp); 342 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) { 343 if (ifa->ifa_addr->sa_family != AF_INET) 344 continue; 345 346 if (ifa->ifa_carp) { 347 if ((*carp_iamatch_p)(ifa, &carpaddr) == 0) 348 continue; 349 sip = &IA_SIN(ifa)->sin_addr; 350 } else { 351 carpaddr = NULL; 352 sip = &IA_SIN(ifa)->sin_addr; 353 } 354 355 if (0 == ((sip->s_addr ^ tip->s_addr) & 356 IA_MASKSIN(ifa)->sin_addr.s_addr)) 357 break; /* found it. */ 358 } 359 IF_ADDR_RUNLOCK(ifp); 360 if (sip == NULL) { 361 printf("%s: cannot find matching address\n", __func__); 362 return; 363 } 364 } 365 if (enaddr == NULL) 366 enaddr = carpaddr ? carpaddr : (u_char *)IF_LLADDR(ifp); 367 368 if ((m = m_gethdr(M_NOWAIT, MT_DATA)) == NULL) 369 return; 370 m->m_len = sizeof(*ah) + 2 * sizeof(struct in_addr) + 371 2 * ifp->if_addrlen; 372 m->m_pkthdr.len = m->m_len; 373 M_ALIGN(m, m->m_len); 374 ah = mtod(m, struct arphdr *); 375 bzero((caddr_t)ah, m->m_len); 376 #ifdef MAC 377 mac_netinet_arp_send(ifp, m); 378 #endif 379 ah->ar_pro = htons(ETHERTYPE_IP); 380 ah->ar_hln = ifp->if_addrlen; /* hardware address length */ 381 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 382 ah->ar_op = htons(ARPOP_REQUEST); 383 bcopy(enaddr, ar_sha(ah), ah->ar_hln); 384 bcopy(sip, ar_spa(ah), ah->ar_pln); 385 bcopy(tip, ar_tpa(ah), ah->ar_pln); 386 sa.sa_family = AF_ARP; 387 sa.sa_len = 2; 388 389 /* Calculate link header for sending frame */ 390 bzero(&ro, sizeof(ro)); 391 linkhdrsize = sizeof(linkhdr); 392 error = arp_fillheader(ifp, ah, 1, linkhdr, &linkhdrsize); 393 if (error != 0 && error != EAFNOSUPPORT) { 394 ARP_LOG(LOG_ERR, "Failed to calculate ARP header on %s: %d\n", 395 if_name(ifp), error); 396 return; 397 } 398 399 ro.ro_prepend = linkhdr; 400 ro.ro_plen = linkhdrsize; 401 ro.ro_flags = 0; 402 403 m->m_flags |= M_BCAST; 404 m_clrprotoflags(m); /* Avoid confusing lower layers. */ 405 (*ifp->if_output)(ifp, m, &sa, &ro); 406 ARPSTAT_INC(txrequests); 407 } 408 409 410 /* 411 * Resolve an IP address into an ethernet address - heavy version. 412 * Used internally by arpresolve(). 413 * We have already checked than we can't use existing lle without 414 * modification so we have to acquire LLE_EXCLUSIVE lle lock. 415 * 416 * On success, desten and flags are filled in and the function returns 0; 417 * If the packet must be held pending resolution, we return EWOULDBLOCK 418 * On other errors, we return the corresponding error code. 419 * Note that m_freem() handles NULL. 420 */ 421 static int 422 arpresolve_full(struct ifnet *ifp, int is_gw, int flags, struct mbuf *m, 423 const struct sockaddr *dst, u_char *desten, uint32_t *pflags, 424 struct llentry **plle) 425 { 426 struct llentry *la = NULL, *la_tmp; 427 struct mbuf *curr = NULL; 428 struct mbuf *next = NULL; 429 int error, renew; 430 char *lladdr; 431 int ll_len; 432 433 if (pflags != NULL) 434 *pflags = 0; 435 if (plle != NULL) 436 *plle = NULL; 437 438 if ((flags & LLE_CREATE) == 0) { 439 IF_AFDATA_RLOCK(ifp); 440 la = lla_lookup(LLTABLE(ifp), LLE_EXCLUSIVE, dst); 441 IF_AFDATA_RUNLOCK(ifp); 442 } 443 if (la == NULL && (ifp->if_flags & (IFF_NOARP | IFF_STATICARP)) == 0) { 444 la = lltable_alloc_entry(LLTABLE(ifp), 0, dst); 445 if (la == NULL) { 446 log(LOG_DEBUG, 447 "arpresolve: can't allocate llinfo for %s on %s\n", 448 inet_ntoa(SIN(dst)->sin_addr), if_name(ifp)); 449 m_freem(m); 450 return (EINVAL); 451 } 452 453 IF_AFDATA_WLOCK(ifp); 454 LLE_WLOCK(la); 455 la_tmp = lla_lookup(LLTABLE(ifp), LLE_EXCLUSIVE, dst); 456 /* Prefer ANY existing lle over newly-created one */ 457 if (la_tmp == NULL) 458 lltable_link_entry(LLTABLE(ifp), la); 459 IF_AFDATA_WUNLOCK(ifp); 460 if (la_tmp != NULL) { 461 lltable_free_entry(LLTABLE(ifp), la); 462 la = la_tmp; 463 } 464 } 465 if (la == NULL) { 466 m_freem(m); 467 return (EINVAL); 468 } 469 470 if ((la->la_flags & LLE_VALID) && 471 ((la->la_flags & LLE_STATIC) || la->la_expire > time_uptime)) { 472 if (flags & LLE_ADDRONLY) { 473 lladdr = la->ll_addr; 474 ll_len = ifp->if_addrlen; 475 } else { 476 lladdr = la->r_linkdata; 477 ll_len = la->r_hdrlen; 478 } 479 bcopy(lladdr, desten, ll_len); 480 481 /* Check if we have feedback request from arptimer() */ 482 if (la->r_skip_req != 0) { 483 LLE_REQ_LOCK(la); 484 la->r_skip_req = 0; /* Notify that entry was used */ 485 LLE_REQ_UNLOCK(la); 486 } 487 if (pflags != NULL) 488 *pflags = la->la_flags & (LLE_VALID|LLE_IFADDR); 489 if (plle) { 490 LLE_ADDREF(la); 491 *plle = la; 492 } 493 LLE_WUNLOCK(la); 494 return (0); 495 } 496 497 renew = (la->la_asked == 0 || la->la_expire != time_uptime); 498 /* 499 * There is an arptab entry, but no ethernet address 500 * response yet. Add the mbuf to the list, dropping 501 * the oldest packet if we have exceeded the system 502 * setting. 503 */ 504 if (m != NULL) { 505 if (la->la_numheld >= V_arp_maxhold) { 506 if (la->la_hold != NULL) { 507 next = la->la_hold->m_nextpkt; 508 m_freem(la->la_hold); 509 la->la_hold = next; 510 la->la_numheld--; 511 ARPSTAT_INC(dropped); 512 } 513 } 514 if (la->la_hold != NULL) { 515 curr = la->la_hold; 516 while (curr->m_nextpkt != NULL) 517 curr = curr->m_nextpkt; 518 curr->m_nextpkt = m; 519 } else 520 la->la_hold = m; 521 la->la_numheld++; 522 } 523 /* 524 * Return EWOULDBLOCK if we have tried less than arp_maxtries. It 525 * will be masked by ether_output(). Return EHOSTDOWN/EHOSTUNREACH 526 * if we have already sent arp_maxtries ARP requests. Retransmit the 527 * ARP request, but not faster than one request per second. 528 */ 529 if (la->la_asked < V_arp_maxtries) 530 error = EWOULDBLOCK; /* First request. */ 531 else 532 error = is_gw != 0 ? EHOSTUNREACH : EHOSTDOWN; 533 534 if (renew) { 535 int canceled; 536 537 LLE_ADDREF(la); 538 la->la_expire = time_uptime; 539 canceled = callout_reset(&la->lle_timer, hz * V_arpt_down, 540 arptimer, la); 541 if (canceled) 542 LLE_REMREF(la); 543 la->la_asked++; 544 LLE_WUNLOCK(la); 545 arprequest(ifp, NULL, &SIN(dst)->sin_addr, NULL); 546 return (error); 547 } 548 549 LLE_WUNLOCK(la); 550 return (error); 551 } 552 553 /* 554 * Resolve an IP address into an ethernet address. 555 */ 556 int 557 arpresolve_addr(struct ifnet *ifp, int flags, const struct sockaddr *dst, 558 char *desten, uint32_t *pflags, struct llentry **plle) 559 { 560 int error; 561 562 flags |= LLE_ADDRONLY; 563 error = arpresolve_full(ifp, 0, flags, NULL, dst, desten, pflags, plle); 564 return (error); 565 } 566 567 568 /* 569 * Lookups link header based on an IP address. 570 * On input: 571 * ifp is the interface we use 572 * is_gw != 0 if @dst represents gateway to some destination 573 * m is the mbuf. May be NULL if we don't have a packet. 574 * dst is the next hop, 575 * desten is the storage to put LL header. 576 * flags returns subset of lle flags: LLE_VALID | LLE_IFADDR 577 * 578 * On success, full/partial link header and flags are filled in and 579 * the function returns 0. 580 * If the packet must be held pending resolution, we return EWOULDBLOCK 581 * On other errors, we return the corresponding error code. 582 * Note that m_freem() handles NULL. 583 */ 584 int 585 arpresolve(struct ifnet *ifp, int is_gw, struct mbuf *m, 586 const struct sockaddr *dst, u_char *desten, uint32_t *pflags, 587 struct llentry **plle) 588 { 589 struct llentry *la = NULL; 590 591 if (pflags != NULL) 592 *pflags = 0; 593 if (plle != NULL) 594 *plle = NULL; 595 596 if (m != NULL) { 597 if (m->m_flags & M_BCAST) { 598 /* broadcast */ 599 (void)memcpy(desten, 600 ifp->if_broadcastaddr, ifp->if_addrlen); 601 return (0); 602 } 603 if (m->m_flags & M_MCAST) { 604 /* multicast */ 605 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); 606 return (0); 607 } 608 } 609 610 IF_AFDATA_RLOCK(ifp); 611 la = lla_lookup(LLTABLE(ifp), LLE_UNLOCKED, dst); 612 if (la != NULL && (la->r_flags & RLLE_VALID) != 0) { 613 /* Entry found, let's copy lle info */ 614 bcopy(la->r_linkdata, desten, la->r_hdrlen); 615 if (pflags != NULL) 616 *pflags = LLE_VALID | (la->r_flags & RLLE_IFADDR); 617 /* Check if we have feedback request from arptimer() */ 618 if (la->r_skip_req != 0) { 619 LLE_REQ_LOCK(la); 620 la->r_skip_req = 0; /* Notify that entry was used */ 621 LLE_REQ_UNLOCK(la); 622 } 623 IF_AFDATA_RUNLOCK(ifp); 624 return (0); 625 } 626 IF_AFDATA_RUNLOCK(ifp); 627 628 return (arpresolve_full(ifp, is_gw, la == NULL ? LLE_CREATE : 0, m, dst, 629 desten, pflags, plle)); 630 } 631 632 /* 633 * Common length and type checks are done here, 634 * then the protocol-specific routine is called. 635 */ 636 static void 637 arpintr(struct mbuf *m) 638 { 639 struct arphdr *ar; 640 struct ifnet *ifp; 641 char *layer; 642 int hlen; 643 644 ifp = m->m_pkthdr.rcvif; 645 646 if (m->m_len < sizeof(struct arphdr) && 647 ((m = m_pullup(m, sizeof(struct arphdr))) == NULL)) { 648 ARP_LOG(LOG_NOTICE, "packet with short header received on %s\n", 649 if_name(ifp)); 650 return; 651 } 652 ar = mtod(m, struct arphdr *); 653 654 /* Check if length is sufficient */ 655 if (m->m_len < arphdr_len(ar)) { 656 m = m_pullup(m, arphdr_len(ar)); 657 if (m == NULL) { 658 ARP_LOG(LOG_NOTICE, "short packet received on %s\n", 659 if_name(ifp)); 660 return; 661 } 662 ar = mtod(m, struct arphdr *); 663 } 664 665 hlen = 0; 666 layer = ""; 667 switch (ntohs(ar->ar_hrd)) { 668 case ARPHRD_ETHER: 669 hlen = ETHER_ADDR_LEN; /* RFC 826 */ 670 layer = "ethernet"; 671 break; 672 case ARPHRD_IEEE802: 673 hlen = 6; /* RFC 1390, FDDI_ADDR_LEN */ 674 layer = "fddi"; 675 break; 676 case ARPHRD_ARCNET: 677 hlen = 1; /* RFC 1201, ARC_ADDR_LEN */ 678 layer = "arcnet"; 679 break; 680 case ARPHRD_INFINIBAND: 681 hlen = 20; /* RFC 4391, INFINIBAND_ALEN */ 682 layer = "infiniband"; 683 break; 684 case ARPHRD_IEEE1394: 685 hlen = 0; /* SHALL be 16 */ /* RFC 2734 */ 686 layer = "firewire"; 687 688 /* 689 * Restrict too long hardware addresses. 690 * Currently we are capable of handling 20-byte 691 * addresses ( sizeof(lle->ll_addr) ) 692 */ 693 if (ar->ar_hln >= 20) 694 hlen = 16; 695 break; 696 default: 697 ARP_LOG(LOG_NOTICE, 698 "packet with unknown hardware format 0x%02d received on " 699 "%s\n", ntohs(ar->ar_hrd), if_name(ifp)); 700 m_freem(m); 701 return; 702 } 703 704 if (hlen != 0 && hlen != ar->ar_hln) { 705 ARP_LOG(LOG_NOTICE, 706 "packet with invalid %s address length %d received on %s\n", 707 layer, ar->ar_hln, if_name(ifp)); 708 m_freem(m); 709 return; 710 } 711 712 ARPSTAT_INC(received); 713 switch (ntohs(ar->ar_pro)) { 714 #ifdef INET 715 case ETHERTYPE_IP: 716 in_arpinput(m); 717 return; 718 #endif 719 } 720 m_freem(m); 721 } 722 723 #ifdef INET 724 /* 725 * ARP for Internet protocols on 10 Mb/s Ethernet. 726 * Algorithm is that given in RFC 826. 727 * In addition, a sanity check is performed on the sender 728 * protocol address, to catch impersonators. 729 * We no longer handle negotiations for use of trailer protocol: 730 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 731 * along with IP replies if we wanted trailers sent to us, 732 * and also sent them in response to IP replies. 733 * This allowed either end to announce the desire to receive 734 * trailer packets. 735 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 736 * but formerly didn't normally send requests. 737 */ 738 static int log_arp_wrong_iface = 1; 739 static int log_arp_movements = 1; 740 static int log_arp_permanent_modify = 1; 741 static int allow_multicast = 0; 742 743 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW, 744 &log_arp_wrong_iface, 0, 745 "log arp packets arriving on the wrong interface"); 746 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_movements, CTLFLAG_RW, 747 &log_arp_movements, 0, 748 "log arp replies from MACs different than the one in the cache"); 749 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_permanent_modify, CTLFLAG_RW, 750 &log_arp_permanent_modify, 0, 751 "log arp replies from MACs different than the one in the permanent arp entry"); 752 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, allow_multicast, CTLFLAG_RW, 753 &allow_multicast, 0, "accept multicast addresses"); 754 755 static void 756 in_arpinput(struct mbuf *m) 757 { 758 struct rm_priotracker in_ifa_tracker; 759 struct arphdr *ah; 760 struct ifnet *ifp = m->m_pkthdr.rcvif; 761 struct llentry *la = NULL, *la_tmp; 762 struct ifaddr *ifa; 763 struct in_ifaddr *ia; 764 struct sockaddr sa; 765 struct in_addr isaddr, itaddr, myaddr; 766 u_int8_t *enaddr = NULL; 767 int op; 768 int bridged = 0, is_bridge = 0; 769 int carped; 770 struct sockaddr_in sin; 771 struct sockaddr *dst; 772 struct nhop4_basic nh4; 773 uint8_t linkhdr[LLE_MAX_LINKHDR]; 774 struct route ro; 775 size_t linkhdrsize; 776 int lladdr_off; 777 int error; 778 779 sin.sin_len = sizeof(struct sockaddr_in); 780 sin.sin_family = AF_INET; 781 sin.sin_addr.s_addr = 0; 782 783 if (ifp->if_bridge) 784 bridged = 1; 785 if (ifp->if_type == IFT_BRIDGE) 786 is_bridge = 1; 787 788 /* 789 * We already have checked that mbuf contains enough contiguous data 790 * to hold entire arp message according to the arp header. 791 */ 792 ah = mtod(m, struct arphdr *); 793 794 /* 795 * ARP is only for IPv4 so we can reject packets with 796 * a protocol length not equal to an IPv4 address. 797 */ 798 if (ah->ar_pln != sizeof(struct in_addr)) { 799 ARP_LOG(LOG_NOTICE, "requested protocol length != %zu\n", 800 sizeof(struct in_addr)); 801 goto drop; 802 } 803 804 if (allow_multicast == 0 && ETHER_IS_MULTICAST(ar_sha(ah))) { 805 ARP_LOG(LOG_NOTICE, "%*D is multicast\n", 806 ifp->if_addrlen, (u_char *)ar_sha(ah), ":"); 807 goto drop; 808 } 809 810 op = ntohs(ah->ar_op); 811 (void)memcpy(&isaddr, ar_spa(ah), sizeof (isaddr)); 812 (void)memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr)); 813 814 if (op == ARPOP_REPLY) 815 ARPSTAT_INC(rxreplies); 816 817 /* 818 * For a bridge, we want to check the address irrespective 819 * of the receive interface. (This will change slightly 820 * when we have clusters of interfaces). 821 */ 822 IN_IFADDR_RLOCK(&in_ifa_tracker); 823 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) { 824 if (((bridged && ia->ia_ifp->if_bridge == ifp->if_bridge) || 825 ia->ia_ifp == ifp) && 826 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr && 827 (ia->ia_ifa.ifa_carp == NULL || 828 (*carp_iamatch_p)(&ia->ia_ifa, &enaddr))) { 829 ifa_ref(&ia->ia_ifa); 830 IN_IFADDR_RUNLOCK(&in_ifa_tracker); 831 goto match; 832 } 833 } 834 LIST_FOREACH(ia, INADDR_HASH(isaddr.s_addr), ia_hash) 835 if (((bridged && ia->ia_ifp->if_bridge == ifp->if_bridge) || 836 ia->ia_ifp == ifp) && 837 isaddr.s_addr == ia->ia_addr.sin_addr.s_addr) { 838 ifa_ref(&ia->ia_ifa); 839 IN_IFADDR_RUNLOCK(&in_ifa_tracker); 840 goto match; 841 } 842 843 #define BDG_MEMBER_MATCHES_ARP(addr, ifp, ia) \ 844 (ia->ia_ifp->if_bridge == ifp->if_softc && \ 845 !bcmp(IF_LLADDR(ia->ia_ifp), IF_LLADDR(ifp), ifp->if_addrlen) && \ 846 addr == ia->ia_addr.sin_addr.s_addr) 847 /* 848 * Check the case when bridge shares its MAC address with 849 * some of its children, so packets are claimed by bridge 850 * itself (bridge_input() does it first), but they are really 851 * meant to be destined to the bridge member. 852 */ 853 if (is_bridge) { 854 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) { 855 if (BDG_MEMBER_MATCHES_ARP(itaddr.s_addr, ifp, ia)) { 856 ifa_ref(&ia->ia_ifa); 857 ifp = ia->ia_ifp; 858 IN_IFADDR_RUNLOCK(&in_ifa_tracker); 859 goto match; 860 } 861 } 862 } 863 #undef BDG_MEMBER_MATCHES_ARP 864 IN_IFADDR_RUNLOCK(&in_ifa_tracker); 865 866 /* 867 * No match, use the first inet address on the receive interface 868 * as a dummy address for the rest of the function. 869 */ 870 IF_ADDR_RLOCK(ifp); 871 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) 872 if (ifa->ifa_addr->sa_family == AF_INET && 873 (ifa->ifa_carp == NULL || 874 (*carp_iamatch_p)(ifa, &enaddr))) { 875 ia = ifatoia(ifa); 876 ifa_ref(ifa); 877 IF_ADDR_RUNLOCK(ifp); 878 goto match; 879 } 880 IF_ADDR_RUNLOCK(ifp); 881 882 /* 883 * If bridging, fall back to using any inet address. 884 */ 885 IN_IFADDR_RLOCK(&in_ifa_tracker); 886 if (!bridged || (ia = TAILQ_FIRST(&V_in_ifaddrhead)) == NULL) { 887 IN_IFADDR_RUNLOCK(&in_ifa_tracker); 888 goto drop; 889 } 890 ifa_ref(&ia->ia_ifa); 891 IN_IFADDR_RUNLOCK(&in_ifa_tracker); 892 match: 893 if (!enaddr) 894 enaddr = (u_int8_t *)IF_LLADDR(ifp); 895 carped = (ia->ia_ifa.ifa_carp != NULL); 896 myaddr = ia->ia_addr.sin_addr; 897 ifa_free(&ia->ia_ifa); 898 if (!bcmp(ar_sha(ah), enaddr, ifp->if_addrlen)) 899 goto drop; /* it's from me, ignore it. */ 900 if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) { 901 ARP_LOG(LOG_NOTICE, "link address is broadcast for IP address " 902 "%s!\n", inet_ntoa(isaddr)); 903 goto drop; 904 } 905 906 if (ifp->if_addrlen != ah->ar_hln) { 907 ARP_LOG(LOG_WARNING, "from %*D: addr len: new %d, " 908 "i/f %d (ignored)\n", ifp->if_addrlen, 909 (u_char *) ar_sha(ah), ":", ah->ar_hln, 910 ifp->if_addrlen); 911 goto drop; 912 } 913 914 /* 915 * Warn if another host is using the same IP address, but only if the 916 * IP address isn't 0.0.0.0, which is used for DHCP only, in which 917 * case we suppress the warning to avoid false positive complaints of 918 * potential misconfiguration. 919 */ 920 if (!bridged && !carped && isaddr.s_addr == myaddr.s_addr && 921 myaddr.s_addr != 0) { 922 ARP_LOG(LOG_ERR, "%*D is using my IP address %s on %s!\n", 923 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 924 inet_ntoa(isaddr), ifp->if_xname); 925 itaddr = myaddr; 926 ARPSTAT_INC(dupips); 927 goto reply; 928 } 929 if (ifp->if_flags & IFF_STATICARP) 930 goto reply; 931 932 bzero(&sin, sizeof(sin)); 933 sin.sin_len = sizeof(struct sockaddr_in); 934 sin.sin_family = AF_INET; 935 sin.sin_addr = isaddr; 936 dst = (struct sockaddr *)&sin; 937 IF_AFDATA_RLOCK(ifp); 938 la = lla_lookup(LLTABLE(ifp), LLE_EXCLUSIVE, dst); 939 IF_AFDATA_RUNLOCK(ifp); 940 if (la != NULL) 941 arp_check_update_lle(ah, isaddr, ifp, bridged, la); 942 else if (itaddr.s_addr == myaddr.s_addr) { 943 /* 944 * Request/reply to our address, but no lle exists yet. 945 * Calculate full link prepend to use in lle. 946 */ 947 linkhdrsize = sizeof(linkhdr); 948 if (lltable_calc_llheader(ifp, AF_INET, ar_sha(ah), linkhdr, 949 &linkhdrsize, &lladdr_off) != 0) 950 goto reply; 951 952 /* Allocate new entry */ 953 la = lltable_alloc_entry(LLTABLE(ifp), 0, dst); 954 if (la == NULL) { 955 956 /* 957 * lle creation may fail if source address belongs 958 * to non-directly connected subnet. However, we 959 * will try to answer the request instead of dropping 960 * frame. 961 */ 962 goto reply; 963 } 964 lltable_set_entry_addr(ifp, la, linkhdr, linkhdrsize, 965 lladdr_off); 966 967 IF_AFDATA_WLOCK(ifp); 968 LLE_WLOCK(la); 969 la_tmp = lla_lookup(LLTABLE(ifp), LLE_EXCLUSIVE, dst); 970 971 /* 972 * Check if lle still does not exists. 973 * If it does, that means that we either 974 * 1) have configured it explicitly, via 975 * 1a) 'arp -s' static entry or 976 * 1b) interface address static record 977 * or 978 * 2) it was the result of sending first packet to-host 979 * or 980 * 3) it was another arp reply packet we handled in 981 * different thread. 982 * 983 * In all cases except 3) we definitely need to prefer 984 * existing lle. For the sake of simplicity, prefer any 985 * existing lle over newly-create one. 986 */ 987 if (la_tmp == NULL) 988 lltable_link_entry(LLTABLE(ifp), la); 989 IF_AFDATA_WUNLOCK(ifp); 990 991 if (la_tmp == NULL) { 992 arp_mark_lle_reachable(la); 993 LLE_WUNLOCK(la); 994 } else { 995 /* Free newly-create entry and handle packet */ 996 lltable_free_entry(LLTABLE(ifp), la); 997 la = la_tmp; 998 la_tmp = NULL; 999 arp_check_update_lle(ah, isaddr, ifp, bridged, la); 1000 /* arp_check_update_lle() returns @la unlocked */ 1001 } 1002 la = NULL; 1003 } 1004 reply: 1005 if (op != ARPOP_REQUEST) 1006 goto drop; 1007 ARPSTAT_INC(rxrequests); 1008 1009 if (itaddr.s_addr == myaddr.s_addr) { 1010 /* Shortcut.. the receiving interface is the target. */ 1011 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 1012 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln); 1013 } else { 1014 struct llentry *lle = NULL; 1015 1016 sin.sin_addr = itaddr; 1017 IF_AFDATA_RLOCK(ifp); 1018 lle = lla_lookup(LLTABLE(ifp), 0, (struct sockaddr *)&sin); 1019 IF_AFDATA_RUNLOCK(ifp); 1020 1021 if ((lle != NULL) && (lle->la_flags & LLE_PUB)) { 1022 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 1023 (void)memcpy(ar_sha(ah), lle->ll_addr, ah->ar_hln); 1024 LLE_RUNLOCK(lle); 1025 } else { 1026 1027 if (lle != NULL) 1028 LLE_RUNLOCK(lle); 1029 1030 if (!V_arp_proxyall) 1031 goto drop; 1032 1033 /* XXX MRT use table 0 for arp reply */ 1034 if (fib4_lookup_nh_basic(0, itaddr, 0, 0, &nh4) != 0) 1035 goto drop; 1036 1037 /* 1038 * Don't send proxies for nodes on the same interface 1039 * as this one came out of, or we'll get into a fight 1040 * over who claims what Ether address. 1041 */ 1042 if (nh4.nh_ifp == ifp) 1043 goto drop; 1044 1045 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 1046 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln); 1047 1048 /* 1049 * Also check that the node which sent the ARP packet 1050 * is on the interface we expect it to be on. This 1051 * avoids ARP chaos if an interface is connected to the 1052 * wrong network. 1053 */ 1054 1055 /* XXX MRT use table 0 for arp checks */ 1056 if (fib4_lookup_nh_basic(0, isaddr, 0, 0, &nh4) != 0) 1057 goto drop; 1058 if (nh4.nh_ifp != ifp) { 1059 ARP_LOG(LOG_INFO, "proxy: ignoring request" 1060 " from %s via %s\n", 1061 inet_ntoa(isaddr), ifp->if_xname); 1062 goto drop; 1063 } 1064 1065 #ifdef DEBUG_PROXY 1066 printf("arp: proxying for %s\n", inet_ntoa(itaddr)); 1067 #endif 1068 } 1069 } 1070 1071 if (itaddr.s_addr == myaddr.s_addr && 1072 IN_LINKLOCAL(ntohl(itaddr.s_addr))) { 1073 /* RFC 3927 link-local IPv4; always reply by broadcast. */ 1074 #ifdef DEBUG_LINKLOCAL 1075 printf("arp: sending reply for link-local addr %s\n", 1076 inet_ntoa(itaddr)); 1077 #endif 1078 m->m_flags |= M_BCAST; 1079 m->m_flags &= ~M_MCAST; 1080 } else { 1081 /* default behaviour; never reply by broadcast. */ 1082 m->m_flags &= ~(M_BCAST|M_MCAST); 1083 } 1084 (void)memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln); 1085 (void)memcpy(ar_spa(ah), &itaddr, ah->ar_pln); 1086 ah->ar_op = htons(ARPOP_REPLY); 1087 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 1088 m->m_len = sizeof(*ah) + (2 * ah->ar_pln) + (2 * ah->ar_hln); 1089 m->m_pkthdr.len = m->m_len; 1090 m->m_pkthdr.rcvif = NULL; 1091 sa.sa_family = AF_ARP; 1092 sa.sa_len = 2; 1093 1094 /* Calculate link header for sending frame */ 1095 bzero(&ro, sizeof(ro)); 1096 linkhdrsize = sizeof(linkhdr); 1097 error = arp_fillheader(ifp, ah, 0, linkhdr, &linkhdrsize); 1098 1099 /* 1100 * arp_fillheader() may fail due to lack of support inside encap request 1101 * routing. This is not necessary an error, AF_ARP can/should be handled 1102 * by if_output(). 1103 */ 1104 if (error != 0 && error != EAFNOSUPPORT) { 1105 ARP_LOG(LOG_ERR, "Failed to calculate ARP header on %s: %d\n", 1106 if_name(ifp), error); 1107 return; 1108 } 1109 1110 ro.ro_prepend = linkhdr; 1111 ro.ro_plen = linkhdrsize; 1112 ro.ro_flags = 0; 1113 1114 m_clrprotoflags(m); /* Avoid confusing lower layers. */ 1115 (*ifp->if_output)(ifp, m, &sa, &ro); 1116 ARPSTAT_INC(txreplies); 1117 return; 1118 1119 drop: 1120 m_freem(m); 1121 } 1122 #endif 1123 1124 /* 1125 * Checks received arp data against existing @la. 1126 * Updates lle state/performs notification if necessary. 1127 */ 1128 static void 1129 arp_check_update_lle(struct arphdr *ah, struct in_addr isaddr, struct ifnet *ifp, 1130 int bridged, struct llentry *la) 1131 { 1132 struct sockaddr sa; 1133 struct mbuf *m_hold, *m_hold_next; 1134 uint8_t linkhdr[LLE_MAX_LINKHDR]; 1135 size_t linkhdrsize; 1136 int lladdr_off; 1137 1138 LLE_WLOCK_ASSERT(la); 1139 1140 /* the following is not an error when doing bridging */ 1141 if (!bridged && la->lle_tbl->llt_ifp != ifp) { 1142 if (log_arp_wrong_iface) 1143 ARP_LOG(LOG_WARNING, "%s is on %s " 1144 "but got reply from %*D on %s\n", 1145 inet_ntoa(isaddr), 1146 la->lle_tbl->llt_ifp->if_xname, 1147 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 1148 ifp->if_xname); 1149 LLE_WUNLOCK(la); 1150 return; 1151 } 1152 if ((la->la_flags & LLE_VALID) && 1153 bcmp(ar_sha(ah), la->ll_addr, ifp->if_addrlen)) { 1154 if (la->la_flags & LLE_STATIC) { 1155 LLE_WUNLOCK(la); 1156 if (log_arp_permanent_modify) 1157 ARP_LOG(LOG_ERR, 1158 "%*D attempts to modify " 1159 "permanent entry for %s on %s\n", 1160 ifp->if_addrlen, 1161 (u_char *)ar_sha(ah), ":", 1162 inet_ntoa(isaddr), ifp->if_xname); 1163 return; 1164 } 1165 if (log_arp_movements) { 1166 ARP_LOG(LOG_INFO, "%s moved from %*D " 1167 "to %*D on %s\n", 1168 inet_ntoa(isaddr), 1169 ifp->if_addrlen, 1170 (u_char *)&la->ll_addr, ":", 1171 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 1172 ifp->if_xname); 1173 } 1174 } 1175 1176 /* Calculate full link prepend to use in lle */ 1177 linkhdrsize = sizeof(linkhdr); 1178 if (lltable_calc_llheader(ifp, AF_INET, ar_sha(ah), linkhdr, 1179 &linkhdrsize, &lladdr_off) != 0) 1180 return; 1181 1182 /* Check if something has changed */ 1183 if (memcmp(la->r_linkdata, linkhdr, linkhdrsize) != 0 || 1184 (la->la_flags & LLE_VALID) == 0) { 1185 /* Try to perform LLE update */ 1186 if (lltable_try_set_entry_addr(ifp, la, linkhdr, linkhdrsize, 1187 lladdr_off) == 0) 1188 return; 1189 1190 /* Clear fast path feedback request if set */ 1191 la->r_skip_req = 0; 1192 } 1193 1194 arp_mark_lle_reachable(la); 1195 1196 /* 1197 * The packets are all freed within the call to the output 1198 * routine. 1199 * 1200 * NB: The lock MUST be released before the call to the 1201 * output routine. 1202 */ 1203 if (la->la_hold != NULL) { 1204 m_hold = la->la_hold; 1205 la->la_hold = NULL; 1206 la->la_numheld = 0; 1207 lltable_fill_sa_entry(la, &sa); 1208 LLE_WUNLOCK(la); 1209 for (; m_hold != NULL; m_hold = m_hold_next) { 1210 m_hold_next = m_hold->m_nextpkt; 1211 m_hold->m_nextpkt = NULL; 1212 /* Avoid confusing lower layers. */ 1213 m_clrprotoflags(m_hold); 1214 (*ifp->if_output)(ifp, m_hold, &sa, NULL); 1215 } 1216 } else 1217 LLE_WUNLOCK(la); 1218 } 1219 1220 static void 1221 arp_mark_lle_reachable(struct llentry *la) 1222 { 1223 int canceled, wtime; 1224 1225 LLE_WLOCK_ASSERT(la); 1226 1227 la->ln_state = ARP_LLINFO_REACHABLE; 1228 EVENTHANDLER_INVOKE(lle_event, la, LLENTRY_RESOLVED); 1229 1230 if (!(la->la_flags & LLE_STATIC)) { 1231 LLE_ADDREF(la); 1232 la->la_expire = time_uptime + V_arpt_keep; 1233 wtime = V_arpt_keep - V_arp_maxtries * V_arpt_rexmit; 1234 if (wtime < 0) 1235 wtime = V_arpt_keep; 1236 canceled = callout_reset(&la->lle_timer, 1237 hz * wtime, arptimer, la); 1238 if (canceled) 1239 LLE_REMREF(la); 1240 } 1241 la->la_asked = 0; 1242 la->la_preempt = V_arp_maxtries; 1243 } 1244 1245 /* 1246 * Add pernament link-layer record for given interface address. 1247 */ 1248 static __noinline void 1249 arp_add_ifa_lle(struct ifnet *ifp, const struct sockaddr *dst) 1250 { 1251 struct llentry *lle, *lle_tmp; 1252 1253 /* 1254 * Interface address LLE record is considered static 1255 * because kernel code relies on LLE_STATIC flag to check 1256 * if these entries can be rewriten by arp updates. 1257 */ 1258 lle = lltable_alloc_entry(LLTABLE(ifp), LLE_IFADDR | LLE_STATIC, dst); 1259 if (lle == NULL) { 1260 log(LOG_INFO, "arp_ifinit: cannot create arp " 1261 "entry for interface address\n"); 1262 return; 1263 } 1264 1265 IF_AFDATA_WLOCK(ifp); 1266 LLE_WLOCK(lle); 1267 /* Unlink any entry if exists */ 1268 lle_tmp = lla_lookup(LLTABLE(ifp), LLE_EXCLUSIVE, dst); 1269 if (lle_tmp != NULL) 1270 lltable_unlink_entry(LLTABLE(ifp), lle_tmp); 1271 1272 lltable_link_entry(LLTABLE(ifp), lle); 1273 IF_AFDATA_WUNLOCK(ifp); 1274 1275 if (lle_tmp != NULL) 1276 EVENTHANDLER_INVOKE(lle_event, lle_tmp, LLENTRY_EXPIRED); 1277 1278 EVENTHANDLER_INVOKE(lle_event, lle, LLENTRY_RESOLVED); 1279 LLE_WUNLOCK(lle); 1280 if (lle_tmp != NULL) 1281 lltable_free_entry(LLTABLE(ifp), lle_tmp); 1282 } 1283 1284 void 1285 arp_ifinit(struct ifnet *ifp, struct ifaddr *ifa) 1286 { 1287 const struct sockaddr_in *dst_in; 1288 const struct sockaddr *dst; 1289 1290 if (ifa->ifa_carp != NULL) 1291 return; 1292 1293 dst = ifa->ifa_addr; 1294 dst_in = (const struct sockaddr_in *)dst; 1295 1296 if (ntohl(dst_in->sin_addr.s_addr) == INADDR_ANY) 1297 return; 1298 arp_announce_ifaddr(ifp, dst_in->sin_addr, IF_LLADDR(ifp)); 1299 1300 arp_add_ifa_lle(ifp, dst); 1301 } 1302 1303 void 1304 arp_announce_ifaddr(struct ifnet *ifp, struct in_addr addr, u_char *enaddr) 1305 { 1306 1307 if (ntohl(addr.s_addr) != INADDR_ANY) 1308 arprequest(ifp, &addr, &addr, enaddr); 1309 } 1310 1311 /* 1312 * Sends gratuitous ARPs for each ifaddr to notify other 1313 * nodes about the address change. 1314 */ 1315 static __noinline void 1316 arp_handle_ifllchange(struct ifnet *ifp) 1317 { 1318 struct ifaddr *ifa; 1319 1320 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) { 1321 if (ifa->ifa_addr->sa_family == AF_INET) 1322 arp_ifinit(ifp, ifa); 1323 } 1324 } 1325 1326 /* 1327 * A handler for interface link layer address change event. 1328 */ 1329 static void 1330 arp_iflladdr(void *arg __unused, struct ifnet *ifp) 1331 { 1332 1333 lltable_update_ifaddr(LLTABLE(ifp)); 1334 1335 if ((ifp->if_flags & IFF_UP) != 0) 1336 arp_handle_ifllchange(ifp); 1337 } 1338 1339 static void 1340 arp_init(void) 1341 { 1342 1343 netisr_register(&arp_nh); 1344 if (IS_DEFAULT_VNET(curvnet)) 1345 iflladdr_tag = EVENTHANDLER_REGISTER(iflladdr_event, 1346 arp_iflladdr, NULL, EVENTHANDLER_PRI_ANY); 1347 } 1348 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0); 1349