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 { 425 struct llentry *la = NULL, *la_tmp; 426 struct mbuf *curr = NULL; 427 struct mbuf *next = NULL; 428 int error, renew; 429 char *lladdr; 430 int ll_len; 431 432 if (pflags != NULL) 433 *pflags = 0; 434 435 if ((flags & LLE_CREATE) == 0) { 436 IF_AFDATA_RLOCK(ifp); 437 la = lla_lookup(LLTABLE(ifp), LLE_EXCLUSIVE, dst); 438 IF_AFDATA_RUNLOCK(ifp); 439 } 440 if (la == NULL && (ifp->if_flags & (IFF_NOARP | IFF_STATICARP)) == 0) { 441 la = lltable_alloc_entry(LLTABLE(ifp), 0, dst); 442 if (la == NULL) { 443 log(LOG_DEBUG, 444 "arpresolve: can't allocate llinfo for %s on %s\n", 445 inet_ntoa(SIN(dst)->sin_addr), if_name(ifp)); 446 m_freem(m); 447 return (EINVAL); 448 } 449 450 IF_AFDATA_WLOCK(ifp); 451 LLE_WLOCK(la); 452 la_tmp = lla_lookup(LLTABLE(ifp), LLE_EXCLUSIVE, dst); 453 /* Prefer ANY existing lle over newly-created one */ 454 if (la_tmp == NULL) 455 lltable_link_entry(LLTABLE(ifp), la); 456 IF_AFDATA_WUNLOCK(ifp); 457 if (la_tmp != NULL) { 458 lltable_free_entry(LLTABLE(ifp), la); 459 la = la_tmp; 460 } 461 } 462 if (la == NULL) { 463 m_freem(m); 464 return (EINVAL); 465 } 466 467 if ((la->la_flags & LLE_VALID) && 468 ((la->la_flags & LLE_STATIC) || la->la_expire > time_uptime)) { 469 if (flags & LLE_ADDRONLY) { 470 lladdr = la->ll_addr; 471 ll_len = ifp->if_addrlen; 472 } else { 473 lladdr = la->r_linkdata; 474 ll_len = la->r_hdrlen; 475 } 476 bcopy(lladdr, desten, ll_len); 477 478 /* Check if we have feedback request from arptimer() */ 479 if (la->r_skip_req != 0) { 480 LLE_REQ_LOCK(la); 481 la->r_skip_req = 0; /* Notify that entry was used */ 482 LLE_REQ_UNLOCK(la); 483 } 484 if (pflags != NULL) 485 *pflags = la->la_flags & (LLE_VALID|LLE_IFADDR); 486 LLE_WUNLOCK(la); 487 return (0); 488 } 489 490 renew = (la->la_asked == 0 || la->la_expire != time_uptime); 491 /* 492 * There is an arptab entry, but no ethernet address 493 * response yet. Add the mbuf to the list, dropping 494 * the oldest packet if we have exceeded the system 495 * setting. 496 */ 497 if (m != NULL) { 498 if (la->la_numheld >= V_arp_maxhold) { 499 if (la->la_hold != NULL) { 500 next = la->la_hold->m_nextpkt; 501 m_freem(la->la_hold); 502 la->la_hold = next; 503 la->la_numheld--; 504 ARPSTAT_INC(dropped); 505 } 506 } 507 if (la->la_hold != NULL) { 508 curr = la->la_hold; 509 while (curr->m_nextpkt != NULL) 510 curr = curr->m_nextpkt; 511 curr->m_nextpkt = m; 512 } else 513 la->la_hold = m; 514 la->la_numheld++; 515 } 516 /* 517 * Return EWOULDBLOCK if we have tried less than arp_maxtries. It 518 * will be masked by ether_output(). Return EHOSTDOWN/EHOSTUNREACH 519 * if we have already sent arp_maxtries ARP requests. Retransmit the 520 * ARP request, but not faster than one request per second. 521 */ 522 if (la->la_asked < V_arp_maxtries) 523 error = EWOULDBLOCK; /* First request. */ 524 else 525 error = is_gw != 0 ? EHOSTUNREACH : EHOSTDOWN; 526 527 if (renew) { 528 int canceled; 529 530 LLE_ADDREF(la); 531 la->la_expire = time_uptime; 532 canceled = callout_reset(&la->lle_timer, hz * V_arpt_down, 533 arptimer, la); 534 if (canceled) 535 LLE_REMREF(la); 536 la->la_asked++; 537 LLE_WUNLOCK(la); 538 arprequest(ifp, NULL, &SIN(dst)->sin_addr, NULL); 539 return (error); 540 } 541 542 LLE_WUNLOCK(la); 543 return (error); 544 } 545 546 /* 547 * Resolve an IP address into an ethernet address. 548 */ 549 int 550 arpresolve_addr(struct ifnet *ifp, int flags, const struct sockaddr *dst, 551 char *desten, uint32_t *pflags) 552 { 553 int error; 554 555 flags |= LLE_ADDRONLY; 556 error = arpresolve_full(ifp, 0, flags, NULL, dst, desten, pflags); 557 return (error); 558 } 559 560 561 /* 562 * Lookups link header based on an IP address. 563 * On input: 564 * ifp is the interface we use 565 * is_gw != 0 if @dst represents gateway to some destination 566 * m is the mbuf. May be NULL if we don't have a packet. 567 * dst is the next hop, 568 * desten is the storage to put LL header. 569 * flags returns subset of lle flags: LLE_VALID | LLE_IFADDR 570 * 571 * On success, full/partial link header and flags are filled in and 572 * the function returns 0. 573 * If the packet must be held pending resolution, we return EWOULDBLOCK 574 * On other errors, we return the corresponding error code. 575 * Note that m_freem() handles NULL. 576 */ 577 int 578 arpresolve(struct ifnet *ifp, int is_gw, struct mbuf *m, 579 const struct sockaddr *dst, u_char *desten, uint32_t *pflags) 580 { 581 struct llentry *la = NULL; 582 583 if (pflags != NULL) 584 *pflags = 0; 585 586 if (m != NULL) { 587 if (m->m_flags & M_BCAST) { 588 /* broadcast */ 589 (void)memcpy(desten, 590 ifp->if_broadcastaddr, ifp->if_addrlen); 591 return (0); 592 } 593 if (m->m_flags & M_MCAST) { 594 /* multicast */ 595 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); 596 return (0); 597 } 598 } 599 600 IF_AFDATA_RLOCK(ifp); 601 la = lla_lookup(LLTABLE(ifp), LLE_UNLOCKED, dst); 602 if (la != NULL && (la->r_flags & RLLE_VALID) != 0) { 603 /* Entry found, let's copy lle info */ 604 bcopy(la->r_linkdata, desten, la->r_hdrlen); 605 if (pflags != NULL) 606 *pflags = LLE_VALID | (la->r_flags & RLLE_IFADDR); 607 /* Check if we have feedback request from arptimer() */ 608 if (la->r_skip_req != 0) { 609 LLE_REQ_LOCK(la); 610 la->r_skip_req = 0; /* Notify that entry was used */ 611 LLE_REQ_UNLOCK(la); 612 } 613 IF_AFDATA_RUNLOCK(ifp); 614 return (0); 615 } 616 IF_AFDATA_RUNLOCK(ifp); 617 618 return (arpresolve_full(ifp, is_gw, la == NULL ? LLE_CREATE : 0, m, dst, 619 desten, pflags)); 620 } 621 622 /* 623 * Common length and type checks are done here, 624 * then the protocol-specific routine is called. 625 */ 626 static void 627 arpintr(struct mbuf *m) 628 { 629 struct arphdr *ar; 630 struct ifnet *ifp; 631 char *layer; 632 int hlen; 633 634 ifp = m->m_pkthdr.rcvif; 635 636 if (m->m_len < sizeof(struct arphdr) && 637 ((m = m_pullup(m, sizeof(struct arphdr))) == NULL)) { 638 ARP_LOG(LOG_NOTICE, "packet with short header received on %s\n", 639 if_name(ifp)); 640 return; 641 } 642 ar = mtod(m, struct arphdr *); 643 644 /* Check if length is sufficient */ 645 if (m->m_len < arphdr_len(ar)) { 646 m = m_pullup(m, arphdr_len(ar)); 647 if (m == NULL) { 648 ARP_LOG(LOG_NOTICE, "short packet received on %s\n", 649 if_name(ifp)); 650 return; 651 } 652 ar = mtod(m, struct arphdr *); 653 } 654 655 hlen = 0; 656 layer = ""; 657 switch (ntohs(ar->ar_hrd)) { 658 case ARPHRD_ETHER: 659 hlen = ETHER_ADDR_LEN; /* RFC 826 */ 660 layer = "ethernet"; 661 break; 662 case ARPHRD_IEEE802: 663 hlen = 6; /* RFC 1390, FDDI_ADDR_LEN */ 664 layer = "fddi"; 665 break; 666 case ARPHRD_ARCNET: 667 hlen = 1; /* RFC 1201, ARC_ADDR_LEN */ 668 layer = "arcnet"; 669 break; 670 case ARPHRD_INFINIBAND: 671 hlen = 20; /* RFC 4391, INFINIBAND_ALEN */ 672 layer = "infiniband"; 673 break; 674 case ARPHRD_IEEE1394: 675 hlen = 0; /* SHALL be 16 */ /* RFC 2734 */ 676 layer = "firewire"; 677 678 /* 679 * Restrict too long hardware addresses. 680 * Currently we are capable of handling 20-byte 681 * addresses ( sizeof(lle->ll_addr) ) 682 */ 683 if (ar->ar_hln >= 20) 684 hlen = 16; 685 break; 686 default: 687 ARP_LOG(LOG_NOTICE, 688 "packet with unknown hardware format 0x%02d received on " 689 "%s\n", ntohs(ar->ar_hrd), if_name(ifp)); 690 m_freem(m); 691 return; 692 } 693 694 if (hlen != 0 && hlen != ar->ar_hln) { 695 ARP_LOG(LOG_NOTICE, 696 "packet with invalid %s address length %d received on %s\n", 697 layer, ar->ar_hln, if_name(ifp)); 698 m_freem(m); 699 return; 700 } 701 702 ARPSTAT_INC(received); 703 switch (ntohs(ar->ar_pro)) { 704 #ifdef INET 705 case ETHERTYPE_IP: 706 in_arpinput(m); 707 return; 708 #endif 709 } 710 m_freem(m); 711 } 712 713 #ifdef INET 714 /* 715 * ARP for Internet protocols on 10 Mb/s Ethernet. 716 * Algorithm is that given in RFC 826. 717 * In addition, a sanity check is performed on the sender 718 * protocol address, to catch impersonators. 719 * We no longer handle negotiations for use of trailer protocol: 720 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 721 * along with IP replies if we wanted trailers sent to us, 722 * and also sent them in response to IP replies. 723 * This allowed either end to announce the desire to receive 724 * trailer packets. 725 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 726 * but formerly didn't normally send requests. 727 */ 728 static int log_arp_wrong_iface = 1; 729 static int log_arp_movements = 1; 730 static int log_arp_permanent_modify = 1; 731 static int allow_multicast = 0; 732 733 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW, 734 &log_arp_wrong_iface, 0, 735 "log arp packets arriving on the wrong interface"); 736 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_movements, CTLFLAG_RW, 737 &log_arp_movements, 0, 738 "log arp replies from MACs different than the one in the cache"); 739 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_permanent_modify, CTLFLAG_RW, 740 &log_arp_permanent_modify, 0, 741 "log arp replies from MACs different than the one in the permanent arp entry"); 742 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, allow_multicast, CTLFLAG_RW, 743 &allow_multicast, 0, "accept multicast addresses"); 744 745 static void 746 in_arpinput(struct mbuf *m) 747 { 748 struct rm_priotracker in_ifa_tracker; 749 struct arphdr *ah; 750 struct ifnet *ifp = m->m_pkthdr.rcvif; 751 struct llentry *la = NULL, *la_tmp; 752 struct ifaddr *ifa; 753 struct in_ifaddr *ia; 754 struct sockaddr sa; 755 struct in_addr isaddr, itaddr, myaddr; 756 u_int8_t *enaddr = NULL; 757 int op; 758 int bridged = 0, is_bridge = 0; 759 int carped; 760 struct sockaddr_in sin; 761 struct sockaddr *dst; 762 struct nhop4_basic nh4; 763 uint8_t linkhdr[LLE_MAX_LINKHDR]; 764 struct route ro; 765 size_t linkhdrsize; 766 int lladdr_off; 767 int error; 768 769 sin.sin_len = sizeof(struct sockaddr_in); 770 sin.sin_family = AF_INET; 771 sin.sin_addr.s_addr = 0; 772 773 if (ifp->if_bridge) 774 bridged = 1; 775 if (ifp->if_type == IFT_BRIDGE) 776 is_bridge = 1; 777 778 /* 779 * We already have checked that mbuf contains enough contiguous data 780 * to hold entire arp message according to the arp header. 781 */ 782 ah = mtod(m, struct arphdr *); 783 784 /* 785 * ARP is only for IPv4 so we can reject packets with 786 * a protocol length not equal to an IPv4 address. 787 */ 788 if (ah->ar_pln != sizeof(struct in_addr)) { 789 ARP_LOG(LOG_NOTICE, "requested protocol length != %zu\n", 790 sizeof(struct in_addr)); 791 goto drop; 792 } 793 794 if (allow_multicast == 0 && ETHER_IS_MULTICAST(ar_sha(ah))) { 795 ARP_LOG(LOG_NOTICE, "%*D is multicast\n", 796 ifp->if_addrlen, (u_char *)ar_sha(ah), ":"); 797 goto drop; 798 } 799 800 op = ntohs(ah->ar_op); 801 (void)memcpy(&isaddr, ar_spa(ah), sizeof (isaddr)); 802 (void)memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr)); 803 804 if (op == ARPOP_REPLY) 805 ARPSTAT_INC(rxreplies); 806 807 /* 808 * For a bridge, we want to check the address irrespective 809 * of the receive interface. (This will change slightly 810 * when we have clusters of interfaces). 811 */ 812 IN_IFADDR_RLOCK(&in_ifa_tracker); 813 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) { 814 if (((bridged && ia->ia_ifp->if_bridge == ifp->if_bridge) || 815 ia->ia_ifp == ifp) && 816 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr && 817 (ia->ia_ifa.ifa_carp == NULL || 818 (*carp_iamatch_p)(&ia->ia_ifa, &enaddr))) { 819 ifa_ref(&ia->ia_ifa); 820 IN_IFADDR_RUNLOCK(&in_ifa_tracker); 821 goto match; 822 } 823 } 824 LIST_FOREACH(ia, INADDR_HASH(isaddr.s_addr), ia_hash) 825 if (((bridged && ia->ia_ifp->if_bridge == ifp->if_bridge) || 826 ia->ia_ifp == ifp) && 827 isaddr.s_addr == ia->ia_addr.sin_addr.s_addr) { 828 ifa_ref(&ia->ia_ifa); 829 IN_IFADDR_RUNLOCK(&in_ifa_tracker); 830 goto match; 831 } 832 833 #define BDG_MEMBER_MATCHES_ARP(addr, ifp, ia) \ 834 (ia->ia_ifp->if_bridge == ifp->if_softc && \ 835 !bcmp(IF_LLADDR(ia->ia_ifp), IF_LLADDR(ifp), ifp->if_addrlen) && \ 836 addr == ia->ia_addr.sin_addr.s_addr) 837 /* 838 * Check the case when bridge shares its MAC address with 839 * some of its children, so packets are claimed by bridge 840 * itself (bridge_input() does it first), but they are really 841 * meant to be destined to the bridge member. 842 */ 843 if (is_bridge) { 844 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) { 845 if (BDG_MEMBER_MATCHES_ARP(itaddr.s_addr, ifp, ia)) { 846 ifa_ref(&ia->ia_ifa); 847 ifp = ia->ia_ifp; 848 IN_IFADDR_RUNLOCK(&in_ifa_tracker); 849 goto match; 850 } 851 } 852 } 853 #undef BDG_MEMBER_MATCHES_ARP 854 IN_IFADDR_RUNLOCK(&in_ifa_tracker); 855 856 /* 857 * No match, use the first inet address on the receive interface 858 * as a dummy address for the rest of the function. 859 */ 860 IF_ADDR_RLOCK(ifp); 861 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) 862 if (ifa->ifa_addr->sa_family == AF_INET && 863 (ifa->ifa_carp == NULL || 864 (*carp_iamatch_p)(ifa, &enaddr))) { 865 ia = ifatoia(ifa); 866 ifa_ref(ifa); 867 IF_ADDR_RUNLOCK(ifp); 868 goto match; 869 } 870 IF_ADDR_RUNLOCK(ifp); 871 872 /* 873 * If bridging, fall back to using any inet address. 874 */ 875 IN_IFADDR_RLOCK(&in_ifa_tracker); 876 if (!bridged || (ia = TAILQ_FIRST(&V_in_ifaddrhead)) == NULL) { 877 IN_IFADDR_RUNLOCK(&in_ifa_tracker); 878 goto drop; 879 } 880 ifa_ref(&ia->ia_ifa); 881 IN_IFADDR_RUNLOCK(&in_ifa_tracker); 882 match: 883 if (!enaddr) 884 enaddr = (u_int8_t *)IF_LLADDR(ifp); 885 carped = (ia->ia_ifa.ifa_carp != NULL); 886 myaddr = ia->ia_addr.sin_addr; 887 ifa_free(&ia->ia_ifa); 888 if (!bcmp(ar_sha(ah), enaddr, ifp->if_addrlen)) 889 goto drop; /* it's from me, ignore it. */ 890 if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) { 891 ARP_LOG(LOG_NOTICE, "link address is broadcast for IP address " 892 "%s!\n", inet_ntoa(isaddr)); 893 goto drop; 894 } 895 896 if (ifp->if_addrlen != ah->ar_hln) { 897 ARP_LOG(LOG_WARNING, "from %*D: addr len: new %d, " 898 "i/f %d (ignored)\n", ifp->if_addrlen, 899 (u_char *) ar_sha(ah), ":", ah->ar_hln, 900 ifp->if_addrlen); 901 goto drop; 902 } 903 904 /* 905 * Warn if another host is using the same IP address, but only if the 906 * IP address isn't 0.0.0.0, which is used for DHCP only, in which 907 * case we suppress the warning to avoid false positive complaints of 908 * potential misconfiguration. 909 */ 910 if (!bridged && !carped && isaddr.s_addr == myaddr.s_addr && 911 myaddr.s_addr != 0) { 912 ARP_LOG(LOG_ERR, "%*D is using my IP address %s on %s!\n", 913 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 914 inet_ntoa(isaddr), ifp->if_xname); 915 itaddr = myaddr; 916 ARPSTAT_INC(dupips); 917 goto reply; 918 } 919 if (ifp->if_flags & IFF_STATICARP) 920 goto reply; 921 922 bzero(&sin, sizeof(sin)); 923 sin.sin_len = sizeof(struct sockaddr_in); 924 sin.sin_family = AF_INET; 925 sin.sin_addr = isaddr; 926 dst = (struct sockaddr *)&sin; 927 IF_AFDATA_RLOCK(ifp); 928 la = lla_lookup(LLTABLE(ifp), LLE_EXCLUSIVE, dst); 929 IF_AFDATA_RUNLOCK(ifp); 930 if (la != NULL) 931 arp_check_update_lle(ah, isaddr, ifp, bridged, la); 932 else if (itaddr.s_addr == myaddr.s_addr) { 933 /* 934 * Request/reply to our address, but no lle exists yet. 935 * Calculate full link prepend to use in lle. 936 */ 937 linkhdrsize = sizeof(linkhdr); 938 if (lltable_calc_llheader(ifp, AF_INET, ar_sha(ah), linkhdr, 939 &linkhdrsize, &lladdr_off) != 0) 940 goto reply; 941 942 /* Allocate new entry */ 943 la = lltable_alloc_entry(LLTABLE(ifp), 0, dst); 944 if (la == NULL) { 945 946 /* 947 * lle creation may fail if source address belongs 948 * to non-directly connected subnet. However, we 949 * will try to answer the request instead of dropping 950 * frame. 951 */ 952 goto reply; 953 } 954 lltable_set_entry_addr(ifp, la, linkhdr, linkhdrsize, 955 lladdr_off); 956 957 IF_AFDATA_WLOCK(ifp); 958 LLE_WLOCK(la); 959 la_tmp = lla_lookup(LLTABLE(ifp), LLE_EXCLUSIVE, dst); 960 961 /* 962 * Check if lle still does not exists. 963 * If it does, that means that we either 964 * 1) have configured it explicitly, via 965 * 1a) 'arp -s' static entry or 966 * 1b) interface address static record 967 * or 968 * 2) it was the result of sending first packet to-host 969 * or 970 * 3) it was another arp reply packet we handled in 971 * different thread. 972 * 973 * In all cases except 3) we definitely need to prefer 974 * existing lle. For the sake of simplicity, prefer any 975 * existing lle over newly-create one. 976 */ 977 if (la_tmp == NULL) 978 lltable_link_entry(LLTABLE(ifp), la); 979 IF_AFDATA_WUNLOCK(ifp); 980 981 if (la_tmp == NULL) { 982 arp_mark_lle_reachable(la); 983 LLE_WUNLOCK(la); 984 } else { 985 /* Free newly-create entry and handle packet */ 986 lltable_free_entry(LLTABLE(ifp), la); 987 la = la_tmp; 988 la_tmp = NULL; 989 arp_check_update_lle(ah, isaddr, ifp, bridged, la); 990 /* arp_check_update_lle() returns @la unlocked */ 991 } 992 la = NULL; 993 } 994 reply: 995 if (op != ARPOP_REQUEST) 996 goto drop; 997 ARPSTAT_INC(rxrequests); 998 999 if (itaddr.s_addr == myaddr.s_addr) { 1000 /* Shortcut.. the receiving interface is the target. */ 1001 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 1002 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln); 1003 } else { 1004 struct llentry *lle = NULL; 1005 1006 sin.sin_addr = itaddr; 1007 IF_AFDATA_RLOCK(ifp); 1008 lle = lla_lookup(LLTABLE(ifp), 0, (struct sockaddr *)&sin); 1009 IF_AFDATA_RUNLOCK(ifp); 1010 1011 if ((lle != NULL) && (lle->la_flags & LLE_PUB)) { 1012 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 1013 (void)memcpy(ar_sha(ah), lle->ll_addr, ah->ar_hln); 1014 LLE_RUNLOCK(lle); 1015 } else { 1016 1017 if (lle != NULL) 1018 LLE_RUNLOCK(lle); 1019 1020 if (!V_arp_proxyall) 1021 goto drop; 1022 1023 /* XXX MRT use table 0 for arp reply */ 1024 if (fib4_lookup_nh_basic(0, itaddr, 0, 0, &nh4) != 0) 1025 goto drop; 1026 1027 /* 1028 * Don't send proxies for nodes on the same interface 1029 * as this one came out of, or we'll get into a fight 1030 * over who claims what Ether address. 1031 */ 1032 if (nh4.nh_ifp == ifp) 1033 goto drop; 1034 1035 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 1036 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln); 1037 1038 /* 1039 * Also check that the node which sent the ARP packet 1040 * is on the interface we expect it to be on. This 1041 * avoids ARP chaos if an interface is connected to the 1042 * wrong network. 1043 */ 1044 1045 /* XXX MRT use table 0 for arp checks */ 1046 if (fib4_lookup_nh_basic(0, isaddr, 0, 0, &nh4) != 0) 1047 goto drop; 1048 if (nh4.nh_ifp != ifp) { 1049 ARP_LOG(LOG_INFO, "proxy: ignoring request" 1050 " from %s via %s\n", 1051 inet_ntoa(isaddr), ifp->if_xname); 1052 goto drop; 1053 } 1054 1055 #ifdef DEBUG_PROXY 1056 printf("arp: proxying for %s\n", inet_ntoa(itaddr)); 1057 #endif 1058 } 1059 } 1060 1061 if (itaddr.s_addr == myaddr.s_addr && 1062 IN_LINKLOCAL(ntohl(itaddr.s_addr))) { 1063 /* RFC 3927 link-local IPv4; always reply by broadcast. */ 1064 #ifdef DEBUG_LINKLOCAL 1065 printf("arp: sending reply for link-local addr %s\n", 1066 inet_ntoa(itaddr)); 1067 #endif 1068 m->m_flags |= M_BCAST; 1069 m->m_flags &= ~M_MCAST; 1070 } else { 1071 /* default behaviour; never reply by broadcast. */ 1072 m->m_flags &= ~(M_BCAST|M_MCAST); 1073 } 1074 (void)memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln); 1075 (void)memcpy(ar_spa(ah), &itaddr, ah->ar_pln); 1076 ah->ar_op = htons(ARPOP_REPLY); 1077 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 1078 m->m_len = sizeof(*ah) + (2 * ah->ar_pln) + (2 * ah->ar_hln); 1079 m->m_pkthdr.len = m->m_len; 1080 m->m_pkthdr.rcvif = NULL; 1081 sa.sa_family = AF_ARP; 1082 sa.sa_len = 2; 1083 1084 /* Calculate link header for sending frame */ 1085 bzero(&ro, sizeof(ro)); 1086 linkhdrsize = sizeof(linkhdr); 1087 error = arp_fillheader(ifp, ah, 0, linkhdr, &linkhdrsize); 1088 1089 /* 1090 * arp_fillheader() may fail due to lack of support inside encap request 1091 * routing. This is not necessary an error, AF_ARP can/should be handled 1092 * by if_output(). 1093 */ 1094 if (error != 0 && error != EAFNOSUPPORT) { 1095 ARP_LOG(LOG_ERR, "Failed to calculate ARP header on %s: %d\n", 1096 if_name(ifp), error); 1097 return; 1098 } 1099 1100 ro.ro_prepend = linkhdr; 1101 ro.ro_plen = linkhdrsize; 1102 ro.ro_flags = 0; 1103 1104 m_clrprotoflags(m); /* Avoid confusing lower layers. */ 1105 (*ifp->if_output)(ifp, m, &sa, &ro); 1106 ARPSTAT_INC(txreplies); 1107 return; 1108 1109 drop: 1110 m_freem(m); 1111 } 1112 #endif 1113 1114 /* 1115 * Checks received arp data against existing @la. 1116 * Updates lle state/performs notification if necessary. 1117 */ 1118 static void 1119 arp_check_update_lle(struct arphdr *ah, struct in_addr isaddr, struct ifnet *ifp, 1120 int bridged, struct llentry *la) 1121 { 1122 struct sockaddr sa; 1123 struct mbuf *m_hold, *m_hold_next; 1124 uint8_t linkhdr[LLE_MAX_LINKHDR]; 1125 size_t linkhdrsize; 1126 int lladdr_off; 1127 1128 LLE_WLOCK_ASSERT(la); 1129 1130 /* the following is not an error when doing bridging */ 1131 if (!bridged && la->lle_tbl->llt_ifp != ifp) { 1132 if (log_arp_wrong_iface) 1133 ARP_LOG(LOG_WARNING, "%s is on %s " 1134 "but got reply from %*D on %s\n", 1135 inet_ntoa(isaddr), 1136 la->lle_tbl->llt_ifp->if_xname, 1137 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 1138 ifp->if_xname); 1139 LLE_WUNLOCK(la); 1140 return; 1141 } 1142 if ((la->la_flags & LLE_VALID) && 1143 bcmp(ar_sha(ah), la->ll_addr, ifp->if_addrlen)) { 1144 if (la->la_flags & LLE_STATIC) { 1145 LLE_WUNLOCK(la); 1146 if (log_arp_permanent_modify) 1147 ARP_LOG(LOG_ERR, 1148 "%*D attempts to modify " 1149 "permanent entry for %s on %s\n", 1150 ifp->if_addrlen, 1151 (u_char *)ar_sha(ah), ":", 1152 inet_ntoa(isaddr), ifp->if_xname); 1153 return; 1154 } 1155 if (log_arp_movements) { 1156 ARP_LOG(LOG_INFO, "%s moved from %*D " 1157 "to %*D on %s\n", 1158 inet_ntoa(isaddr), 1159 ifp->if_addrlen, 1160 (u_char *)&la->ll_addr, ":", 1161 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 1162 ifp->if_xname); 1163 } 1164 } 1165 1166 /* Calculate full link prepend to use in lle */ 1167 linkhdrsize = sizeof(linkhdr); 1168 if (lltable_calc_llheader(ifp, AF_INET, ar_sha(ah), linkhdr, 1169 &linkhdrsize, &lladdr_off) != 0) 1170 return; 1171 1172 /* Check if something has changed */ 1173 if (memcmp(la->r_linkdata, linkhdr, linkhdrsize) != 0 || 1174 (la->la_flags & LLE_VALID) == 0) { 1175 /* Try to perform LLE update */ 1176 if (lltable_try_set_entry_addr(ifp, la, linkhdr, linkhdrsize, 1177 lladdr_off) == 0) 1178 return; 1179 1180 /* Clear fast path feedback request if set */ 1181 la->r_skip_req = 0; 1182 } 1183 1184 arp_mark_lle_reachable(la); 1185 1186 /* 1187 * The packets are all freed within the call to the output 1188 * routine. 1189 * 1190 * NB: The lock MUST be released before the call to the 1191 * output routine. 1192 */ 1193 if (la->la_hold != NULL) { 1194 m_hold = la->la_hold; 1195 la->la_hold = NULL; 1196 la->la_numheld = 0; 1197 lltable_fill_sa_entry(la, &sa); 1198 LLE_WUNLOCK(la); 1199 for (; m_hold != NULL; m_hold = m_hold_next) { 1200 m_hold_next = m_hold->m_nextpkt; 1201 m_hold->m_nextpkt = NULL; 1202 /* Avoid confusing lower layers. */ 1203 m_clrprotoflags(m_hold); 1204 (*ifp->if_output)(ifp, m_hold, &sa, NULL); 1205 } 1206 } else 1207 LLE_WUNLOCK(la); 1208 } 1209 1210 static void 1211 arp_mark_lle_reachable(struct llentry *la) 1212 { 1213 int canceled, wtime; 1214 1215 LLE_WLOCK_ASSERT(la); 1216 1217 la->ln_state = ARP_LLINFO_REACHABLE; 1218 EVENTHANDLER_INVOKE(lle_event, la, LLENTRY_RESOLVED); 1219 1220 if (!(la->la_flags & LLE_STATIC)) { 1221 LLE_ADDREF(la); 1222 la->la_expire = time_uptime + V_arpt_keep; 1223 wtime = V_arpt_keep - V_arp_maxtries * V_arpt_rexmit; 1224 if (wtime < 0) 1225 wtime = V_arpt_keep; 1226 canceled = callout_reset(&la->lle_timer, 1227 hz * wtime, arptimer, la); 1228 if (canceled) 1229 LLE_REMREF(la); 1230 } 1231 la->la_asked = 0; 1232 la->la_preempt = V_arp_maxtries; 1233 } 1234 1235 /* 1236 * Add pernament link-layer record for given interface address. 1237 */ 1238 static __noinline void 1239 arp_add_ifa_lle(struct ifnet *ifp, const struct sockaddr *dst) 1240 { 1241 struct llentry *lle, *lle_tmp; 1242 1243 /* 1244 * Interface address LLE record is considered static 1245 * because kernel code relies on LLE_STATIC flag to check 1246 * if these entries can be rewriten by arp updates. 1247 */ 1248 lle = lltable_alloc_entry(LLTABLE(ifp), LLE_IFADDR | LLE_STATIC, dst); 1249 if (lle == NULL) { 1250 log(LOG_INFO, "arp_ifinit: cannot create arp " 1251 "entry for interface address\n"); 1252 return; 1253 } 1254 1255 IF_AFDATA_WLOCK(ifp); 1256 LLE_WLOCK(lle); 1257 /* Unlink any entry if exists */ 1258 lle_tmp = lla_lookup(LLTABLE(ifp), LLE_EXCLUSIVE, dst); 1259 if (lle_tmp != NULL) 1260 lltable_unlink_entry(LLTABLE(ifp), lle_tmp); 1261 1262 lltable_link_entry(LLTABLE(ifp), lle); 1263 IF_AFDATA_WUNLOCK(ifp); 1264 1265 if (lle_tmp != NULL) 1266 EVENTHANDLER_INVOKE(lle_event, lle_tmp, LLENTRY_EXPIRED); 1267 1268 EVENTHANDLER_INVOKE(lle_event, lle, LLENTRY_RESOLVED); 1269 LLE_WUNLOCK(lle); 1270 if (lle_tmp != NULL) 1271 lltable_free_entry(LLTABLE(ifp), lle_tmp); 1272 } 1273 1274 void 1275 arp_ifinit(struct ifnet *ifp, struct ifaddr *ifa) 1276 { 1277 const struct sockaddr_in *dst_in; 1278 const struct sockaddr *dst; 1279 1280 if (ifa->ifa_carp != NULL) 1281 return; 1282 1283 dst = ifa->ifa_addr; 1284 dst_in = (const struct sockaddr_in *)dst; 1285 1286 if (ntohl(dst_in->sin_addr.s_addr) == INADDR_ANY) 1287 return; 1288 arp_announce_ifaddr(ifp, dst_in->sin_addr, IF_LLADDR(ifp)); 1289 1290 arp_add_ifa_lle(ifp, dst); 1291 } 1292 1293 void 1294 arp_announce_ifaddr(struct ifnet *ifp, struct in_addr addr, u_char *enaddr) 1295 { 1296 1297 if (ntohl(addr.s_addr) != INADDR_ANY) 1298 arprequest(ifp, &addr, &addr, enaddr); 1299 } 1300 1301 /* 1302 * Sends gratuitous ARPs for each ifaddr to notify other 1303 * nodes about the address change. 1304 */ 1305 static __noinline void 1306 arp_handle_ifllchange(struct ifnet *ifp) 1307 { 1308 struct ifaddr *ifa; 1309 1310 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) { 1311 if (ifa->ifa_addr->sa_family == AF_INET) 1312 arp_ifinit(ifp, ifa); 1313 } 1314 } 1315 1316 /* 1317 * A handler for interface link layer address change event. 1318 */ 1319 static void 1320 arp_iflladdr(void *arg __unused, struct ifnet *ifp) 1321 { 1322 1323 lltable_update_ifaddr(LLTABLE(ifp)); 1324 1325 if ((ifp->if_flags & IFF_UP) != 0) 1326 arp_handle_ifllchange(ifp); 1327 } 1328 1329 static void 1330 arp_init(void) 1331 { 1332 1333 netisr_register(&arp_nh); 1334 if (IS_DEFAULT_VNET(curvnet)) 1335 iflladdr_tag = EVENTHANDLER_REGISTER(iflladdr_event, 1336 arp_iflladdr, NULL, EVENTHANDLER_PRI_ANY); 1337 } 1338 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0); 1339