if_ether.c revision 194739
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: head/sys/netinet/if_ether.c 194739 2009-06-23 17:03:45Z bz $"); 40 41#include "opt_inet.h" 42#include "opt_carp.h" 43 44#include <sys/param.h> 45#include <sys/kernel.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/socket.h> 53#include <sys/syslog.h> 54#include <sys/vimage.h> 55 56#include <net/if.h> 57#include <net/if_dl.h> 58#include <net/if_types.h> 59#include <net/netisr.h> 60#include <net/if_llc.h> 61#include <net/ethernet.h> 62#include <net/route.h> 63 64#include <netinet/in.h> 65#include <netinet/in_var.h> 66#include <net/if_llatbl.h> 67#include <netinet/if_ether.h> 68#include <netinet/vinet.h> 69 70#include <net/if_arc.h> 71#include <net/iso88025.h> 72 73#ifdef DEV_CARP 74#include <netinet/ip_carp.h> 75#endif 76 77#include <security/mac/mac_framework.h> 78 79#define SIN(s) ((struct sockaddr_in *)s) 80#define SDL(s) ((struct sockaddr_dl *)s) 81 82SYSCTL_DECL(_net_link_ether); 83SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, ""); 84 85/* timer values */ 86#ifdef VIMAGE_GLOBALS 87static int arpt_keep; /* once resolved, good for 20 more minutes */ 88static int arp_maxtries; 89int useloopback; /* use loopback interface for local traffic */ 90static int arp_proxyall; 91#endif 92 93SYSCTL_V_INT(V_NET, vnet_inet, _net_link_ether_inet, OID_AUTO, max_age, 94 CTLFLAG_RW, arpt_keep, 0, "ARP entry lifetime in seconds"); 95 96SYSCTL_V_INT(V_NET, vnet_inet, _net_link_ether_inet, OID_AUTO, maxtries, 97 CTLFLAG_RW, arp_maxtries, 0, 98 "ARP resolution attempts before returning error"); 99SYSCTL_V_INT(V_NET, vnet_inet, _net_link_ether_inet, OID_AUTO, useloopback, 100 CTLFLAG_RW, useloopback, 0, 101 "Use the loopback interface for local traffic"); 102SYSCTL_V_INT(V_NET, vnet_inet, _net_link_ether_inet, OID_AUTO, proxyall, 103 CTLFLAG_RW, arp_proxyall, 0, 104 "Enable proxy ARP for all suitable requests"); 105 106static void arp_init(void); 107static int arp_iattach(const void *); 108void arprequest(struct ifnet *, 109 struct in_addr *, struct in_addr *, u_char *); 110static void arpintr(struct mbuf *); 111static void arptimer(void *); 112#ifdef INET 113static void in_arpinput(struct mbuf *); 114#endif 115 116static const struct netisr_handler arp_nh = { 117 .nh_name = "arp", 118 .nh_handler = arpintr, 119 .nh_proto = NETISR_ARP, 120 .nh_policy = NETISR_POLICY_SOURCE, 121}; 122 123#ifndef VIMAGE_GLOBALS 124static const vnet_modinfo_t vnet_arp_modinfo = { 125 .vmi_id = VNET_MOD_ARP, 126 .vmi_name = "arp", 127 .vmi_dependson = VNET_MOD_INET, 128 .vmi_iattach = arp_iattach 129}; 130#endif /* !VIMAGE_GLOBALS */ 131 132#ifdef AF_INET 133void arp_ifscrub(struct ifnet *ifp, uint32_t addr); 134 135/* 136 * called by in_ifscrub to remove entry from the table when 137 * the interface goes away 138 */ 139void 140arp_ifscrub(struct ifnet *ifp, uint32_t addr) 141{ 142 struct sockaddr_in addr4; 143 144 bzero((void *)&addr4, sizeof(addr4)); 145 addr4.sin_len = sizeof(addr4); 146 addr4.sin_family = AF_INET; 147 addr4.sin_addr.s_addr = addr; 148 CURVNET_SET(ifp->if_vnet); 149 IF_AFDATA_LOCK(ifp); 150 lla_lookup(LLTABLE(ifp), (LLE_DELETE | LLE_IFADDR), 151 (struct sockaddr *)&addr4); 152 IF_AFDATA_UNLOCK(ifp); 153 CURVNET_RESTORE(); 154} 155#endif 156 157/* 158 * Timeout routine. Age arp_tab entries periodically. 159 */ 160static void 161arptimer(void *arg) 162{ 163 struct ifnet *ifp; 164 struct llentry *lle = (struct llentry *)arg; 165 166 if (lle == NULL) { 167 panic("%s: NULL entry!\n", __func__); 168 return; 169 } 170 ifp = lle->lle_tbl->llt_ifp; 171 IF_AFDATA_LOCK(ifp); 172 LLE_WLOCK(lle); 173 if (((lle->la_flags & LLE_DELETED) 174 || (time_second >= lle->la_expire)) 175 && (!callout_pending(&lle->la_timer) && 176 callout_active(&lle->la_timer))) 177 (void) llentry_free(lle); 178 else { 179 /* 180 * Still valid, just drop our reference 181 */ 182 LLE_FREE_LOCKED(lle); 183 } 184 IF_AFDATA_UNLOCK(ifp); 185} 186 187/* 188 * Broadcast an ARP request. Caller specifies: 189 * - arp header source ip address 190 * - arp header target ip address 191 * - arp header source ethernet address 192 */ 193void 194arprequest(struct ifnet *ifp, struct in_addr *sip, struct in_addr *tip, 195 u_char *enaddr) 196{ 197 struct mbuf *m; 198 struct arphdr *ah; 199 struct sockaddr sa; 200 201 if (sip == NULL) { 202 /* XXX don't believe this can happen (or explain why) */ 203 /* 204 * The caller did not supply a source address, try to find 205 * a compatible one among those assigned to this interface. 206 */ 207 struct ifaddr *ifa; 208 209 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) { 210 if (!ifa->ifa_addr || 211 ifa->ifa_addr->sa_family != AF_INET) 212 continue; 213 sip = &SIN(ifa->ifa_addr)->sin_addr; 214 if (0 == ((sip->s_addr ^ tip->s_addr) & 215 SIN(ifa->ifa_netmask)->sin_addr.s_addr) ) 216 break; /* found it. */ 217 } 218 if (sip == NULL) { 219 printf("%s: cannot find matching address\n", __func__); 220 return; 221 } 222 } 223 224 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 225 return; 226 m->m_len = sizeof(*ah) + 2*sizeof(struct in_addr) + 227 2*ifp->if_data.ifi_addrlen; 228 m->m_pkthdr.len = m->m_len; 229 MH_ALIGN(m, m->m_len); 230 ah = mtod(m, struct arphdr *); 231 bzero((caddr_t)ah, m->m_len); 232#ifdef MAC 233 mac_netinet_arp_send(ifp, m); 234#endif 235 ah->ar_pro = htons(ETHERTYPE_IP); 236 ah->ar_hln = ifp->if_addrlen; /* hardware address length */ 237 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 238 ah->ar_op = htons(ARPOP_REQUEST); 239 bcopy((caddr_t)enaddr, (caddr_t)ar_sha(ah), ah->ar_hln); 240 bcopy((caddr_t)sip, (caddr_t)ar_spa(ah), ah->ar_pln); 241 bcopy((caddr_t)tip, (caddr_t)ar_tpa(ah), ah->ar_pln); 242 sa.sa_family = AF_ARP; 243 sa.sa_len = 2; 244 m->m_flags |= M_BCAST; 245 (*ifp->if_output)(ifp, m, &sa, NULL); 246} 247 248/* 249 * Resolve an IP address into an ethernet address. 250 * On input: 251 * ifp is the interface we use 252 * rt0 is the route to the final destination (possibly useless) 253 * m is the mbuf. May be NULL if we don't have a packet. 254 * dst is the next hop, 255 * desten is where we want the address. 256 * 257 * On success, desten is filled in and the function returns 0; 258 * If the packet must be held pending resolution, we return EWOULDBLOCK 259 * On other errors, we return the corresponding error code. 260 * Note that m_freem() handles NULL. 261 */ 262int 263arpresolve(struct ifnet *ifp, struct rtentry *rt0, struct mbuf *m, 264 struct sockaddr *dst, u_char *desten, struct llentry **lle) 265{ 266 INIT_VNET_INET(ifp->if_vnet); 267 struct llentry *la = 0; 268 u_int flags = 0; 269 int error, renew; 270 271 *lle = NULL; 272 if (m != NULL) { 273 if (m->m_flags & M_BCAST) { 274 /* broadcast */ 275 (void)memcpy(desten, 276 ifp->if_broadcastaddr, ifp->if_addrlen); 277 return (0); 278 } 279 if (m->m_flags & M_MCAST && ifp->if_type != IFT_ARCNET) { 280 /* multicast */ 281 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); 282 return (0); 283 } 284 } 285 /* XXXXX 286 */ 287retry: 288 IF_AFDATA_RLOCK(ifp); 289 la = lla_lookup(LLTABLE(ifp), flags, dst); 290 IF_AFDATA_RUNLOCK(ifp); 291 if ((la == NULL) && ((flags & LLE_EXCLUSIVE) == 0) 292 && ((ifp->if_flags & (IFF_NOARP | IFF_STATICARP)) == 0)) { 293 flags |= (LLE_CREATE | LLE_EXCLUSIVE); 294 IF_AFDATA_WLOCK(ifp); 295 la = lla_lookup(LLTABLE(ifp), flags, dst); 296 IF_AFDATA_WUNLOCK(ifp); 297 } 298 if (la == NULL) { 299 if (flags & LLE_CREATE) 300 log(LOG_DEBUG, 301 "arpresolve: can't allocate llinfo for %s\n", 302 inet_ntoa(SIN(dst)->sin_addr)); 303 m_freem(m); 304 return (EINVAL); 305 } 306 307 if ((la->la_flags & LLE_VALID) && 308 ((la->la_flags & LLE_STATIC) || la->la_expire > time_uptime)) { 309 bcopy(&la->ll_addr, desten, ifp->if_addrlen); 310 /* 311 * If entry has an expiry time and it is approaching, 312 * see if we need to send an ARP request within this 313 * arpt_down interval. 314 */ 315 if (!(la->la_flags & LLE_STATIC) && 316 time_uptime + la->la_preempt > la->la_expire) { 317 arprequest(ifp, NULL, 318 &SIN(dst)->sin_addr, IF_LLADDR(ifp)); 319 320 la->la_preempt--; 321 } 322 323 *lle = la; 324 error = 0; 325 goto done; 326 } 327 328 if (la->la_flags & LLE_STATIC) { /* should not happen! */ 329 log(LOG_DEBUG, "arpresolve: ouch, empty static llinfo for %s\n", 330 inet_ntoa(SIN(dst)->sin_addr)); 331 m_freem(m); 332 error = EINVAL; 333 goto done; 334 } 335 336 renew = (la->la_asked == 0 || la->la_expire != time_uptime); 337 if ((renew || m != NULL) && (flags & LLE_EXCLUSIVE) == 0) { 338 flags |= LLE_EXCLUSIVE; 339 LLE_RUNLOCK(la); 340 goto retry; 341 } 342 /* 343 * There is an arptab entry, but no ethernet address 344 * response yet. Replace the held mbuf with this 345 * latest one. 346 */ 347 if (m != NULL) { 348 if (la->la_hold != NULL) 349 m_freem(la->la_hold); 350 la->la_hold = m; 351 if (renew == 0 && (flags & LLE_EXCLUSIVE)) { 352 flags &= ~LLE_EXCLUSIVE; 353 LLE_DOWNGRADE(la); 354 } 355 356 } 357 /* 358 * Return EWOULDBLOCK if we have tried less than arp_maxtries. It 359 * will be masked by ether_output(). Return EHOSTDOWN/EHOSTUNREACH 360 * if we have already sent arp_maxtries ARP requests. Retransmit the 361 * ARP request, but not faster than one request per second. 362 */ 363 if (la->la_asked < V_arp_maxtries) 364 error = EWOULDBLOCK; /* First request. */ 365 else 366 error = 367 (rt0->rt_flags & RTF_GATEWAY) ? EHOSTDOWN : EHOSTUNREACH; 368 369 if (renew) { 370 LLE_ADDREF(la); 371 la->la_expire = time_uptime; 372 callout_reset(&la->la_timer, hz, arptimer, la); 373 la->la_asked++; 374 LLE_WUNLOCK(la); 375 arprequest(ifp, NULL, &SIN(dst)->sin_addr, 376 IF_LLADDR(ifp)); 377 return (error); 378 } 379done: 380 if (flags & LLE_EXCLUSIVE) 381 LLE_WUNLOCK(la); 382 else 383 LLE_RUNLOCK(la); 384 return (error); 385} 386 387/* 388 * Common length and type checks are done here, 389 * then the protocol-specific routine is called. 390 */ 391static void 392arpintr(struct mbuf *m) 393{ 394 struct arphdr *ar; 395 396 if (m->m_len < sizeof(struct arphdr) && 397 ((m = m_pullup(m, sizeof(struct arphdr))) == NULL)) { 398 log(LOG_ERR, "arp: runt packet -- m_pullup failed\n"); 399 return; 400 } 401 ar = mtod(m, struct arphdr *); 402 403 if (ntohs(ar->ar_hrd) != ARPHRD_ETHER && 404 ntohs(ar->ar_hrd) != ARPHRD_IEEE802 && 405 ntohs(ar->ar_hrd) != ARPHRD_ARCNET && 406 ntohs(ar->ar_hrd) != ARPHRD_IEEE1394) { 407 log(LOG_ERR, "arp: unknown hardware address format (0x%2D)\n", 408 (unsigned char *)&ar->ar_hrd, ""); 409 m_freem(m); 410 return; 411 } 412 413 if (m->m_len < arphdr_len(ar)) { 414 if ((m = m_pullup(m, arphdr_len(ar))) == NULL) { 415 log(LOG_ERR, "arp: runt packet\n"); 416 m_freem(m); 417 return; 418 } 419 ar = mtod(m, struct arphdr *); 420 } 421 422 switch (ntohs(ar->ar_pro)) { 423#ifdef INET 424 case ETHERTYPE_IP: 425 in_arpinput(m); 426 return; 427#endif 428 } 429 m_freem(m); 430} 431 432#ifdef INET 433/* 434 * ARP for Internet protocols on 10 Mb/s Ethernet. 435 * Algorithm is that given in RFC 826. 436 * In addition, a sanity check is performed on the sender 437 * protocol address, to catch impersonators. 438 * We no longer handle negotiations for use of trailer protocol: 439 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 440 * along with IP replies if we wanted trailers sent to us, 441 * and also sent them in response to IP replies. 442 * This allowed either end to announce the desire to receive 443 * trailer packets. 444 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 445 * but formerly didn't normally send requests. 446 */ 447static int log_arp_wrong_iface = 1; 448static int log_arp_movements = 1; 449static int log_arp_permanent_modify = 1; 450 451SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW, 452 &log_arp_wrong_iface, 0, 453 "log arp packets arriving on the wrong interface"); 454SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_movements, CTLFLAG_RW, 455 &log_arp_movements, 0, 456 "log arp replies from MACs different than the one in the cache"); 457SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_permanent_modify, CTLFLAG_RW, 458 &log_arp_permanent_modify, 0, 459 "log arp replies from MACs different than the one in the permanent arp entry"); 460 461 462static void 463in_arpinput(struct mbuf *m) 464{ 465 struct arphdr *ah; 466 struct ifnet *ifp = m->m_pkthdr.rcvif; 467 struct llentry *la = NULL; 468 struct rtentry *rt; 469 struct ifaddr *ifa; 470 struct in_ifaddr *ia; 471 struct sockaddr sa; 472 struct in_addr isaddr, itaddr, myaddr; 473 u_int8_t *enaddr = NULL; 474 int op, flags; 475 struct mbuf *m0; 476 int req_len; 477 int bridged = 0, is_bridge = 0; 478#ifdef DEV_CARP 479 int carp_match = 0; 480#endif 481 struct sockaddr_in sin; 482 sin.sin_len = sizeof(struct sockaddr_in); 483 sin.sin_family = AF_INET; 484 sin.sin_addr.s_addr = 0; 485 INIT_VNET_INET(ifp->if_vnet); 486 487 if (ifp->if_bridge) 488 bridged = 1; 489 if (ifp->if_type == IFT_BRIDGE) 490 is_bridge = 1; 491 492 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 493 if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) { 494 log(LOG_ERR, "in_arp: runt packet -- m_pullup failed\n"); 495 return; 496 } 497 498 ah = mtod(m, struct arphdr *); 499 op = ntohs(ah->ar_op); 500 (void)memcpy(&isaddr, ar_spa(ah), sizeof (isaddr)); 501 (void)memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr)); 502 503 /* 504 * For a bridge, we want to check the address irrespective 505 * of the receive interface. (This will change slightly 506 * when we have clusters of interfaces). 507 * If the interface does not match, but the recieving interface 508 * is part of carp, we call carp_iamatch to see if this is a 509 * request for the virtual host ip. 510 * XXX: This is really ugly! 511 */ 512 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) { 513 if (((bridged && ia->ia_ifp->if_bridge != NULL) || 514 ia->ia_ifp == ifp) && 515 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) 516 goto match; 517#ifdef DEV_CARP 518 if (ifp->if_carp != NULL && 519 carp_iamatch(ifp->if_carp, ia, &isaddr, &enaddr) && 520 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) { 521 carp_match = 1; 522 goto match; 523 } 524#endif 525 } 526 LIST_FOREACH(ia, INADDR_HASH(isaddr.s_addr), ia_hash) 527 if (((bridged && ia->ia_ifp->if_bridge != NULL) || 528 ia->ia_ifp == ifp) && 529 isaddr.s_addr == ia->ia_addr.sin_addr.s_addr) 530 goto match; 531 532#define BDG_MEMBER_MATCHES_ARP(addr, ifp, ia) \ 533 (ia->ia_ifp->if_bridge == ifp->if_softc && \ 534 !bcmp(IF_LLADDR(ia->ia_ifp), IF_LLADDR(ifp), ifp->if_addrlen) && \ 535 addr == ia->ia_addr.sin_addr.s_addr) 536 /* 537 * Check the case when bridge shares its MAC address with 538 * some of its children, so packets are claimed by bridge 539 * itself (bridge_input() does it first), but they are really 540 * meant to be destined to the bridge member. 541 */ 542 if (is_bridge) { 543 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) { 544 if (BDG_MEMBER_MATCHES_ARP(itaddr.s_addr, ifp, ia)) { 545 ifp = ia->ia_ifp; 546 goto match; 547 } 548 } 549 } 550#undef BDG_MEMBER_MATCHES_ARP 551 552 /* 553 * No match, use the first inet address on the receive interface 554 * as a dummy address for the rest of the function. 555 */ 556 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) 557 if (ifa->ifa_addr->sa_family == AF_INET) { 558 ia = ifatoia(ifa); 559 goto match; 560 } 561 /* 562 * If bridging, fall back to using any inet address. 563 */ 564 if (!bridged || (ia = TAILQ_FIRST(&V_in_ifaddrhead)) == NULL) 565 goto drop; 566match: 567 if (!enaddr) 568 enaddr = (u_int8_t *)IF_LLADDR(ifp); 569 myaddr = ia->ia_addr.sin_addr; 570 if (!bcmp(ar_sha(ah), enaddr, ifp->if_addrlen)) 571 goto drop; /* it's from me, ignore it. */ 572 if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) { 573 log(LOG_ERR, 574 "arp: link address is broadcast for IP address %s!\n", 575 inet_ntoa(isaddr)); 576 goto drop; 577 } 578 /* 579 * Warn if another host is using the same IP address, but only if the 580 * IP address isn't 0.0.0.0, which is used for DHCP only, in which 581 * case we suppress the warning to avoid false positive complaints of 582 * potential misconfiguration. 583 */ 584 if (!bridged && isaddr.s_addr == myaddr.s_addr && myaddr.s_addr != 0) { 585 log(LOG_ERR, 586 "arp: %*D is using my IP address %s on %s!\n", 587 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 588 inet_ntoa(isaddr), ifp->if_xname); 589 itaddr = myaddr; 590 goto reply; 591 } 592 if (ifp->if_flags & IFF_STATICARP) 593 goto reply; 594 595 bzero(&sin, sizeof(sin)); 596 sin.sin_len = sizeof(struct sockaddr_in); 597 sin.sin_family = AF_INET; 598 sin.sin_addr = isaddr; 599 flags = (itaddr.s_addr == myaddr.s_addr) ? LLE_CREATE : 0; 600 flags |= LLE_EXCLUSIVE; 601 IF_AFDATA_LOCK(ifp); 602 la = lla_lookup(LLTABLE(ifp), flags, (struct sockaddr *)&sin); 603 IF_AFDATA_UNLOCK(ifp); 604 if (la != NULL) { 605 /* the following is not an error when doing bridging */ 606 if (!bridged && la->lle_tbl->llt_ifp != ifp 607#ifdef DEV_CARP 608 && (ifp->if_type != IFT_CARP || !carp_match) 609#endif 610 ) { 611 if (log_arp_wrong_iface) 612 log(LOG_ERR, "arp: %s is on %s " 613 "but got reply from %*D on %s\n", 614 inet_ntoa(isaddr), 615 la->lle_tbl->llt_ifp->if_xname, 616 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 617 ifp->if_xname); 618 goto reply; 619 } 620 if ((la->la_flags & LLE_VALID) && 621 bcmp(ar_sha(ah), &la->ll_addr, ifp->if_addrlen)) { 622 if (la->la_flags & LLE_STATIC) { 623 log(LOG_ERR, 624 "arp: %*D attempts to modify permanent " 625 "entry for %s on %s\n", 626 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 627 inet_ntoa(isaddr), ifp->if_xname); 628 goto reply; 629 } 630 if (log_arp_movements) { 631 log(LOG_INFO, "arp: %s moved from %*D " 632 "to %*D on %s\n", 633 inet_ntoa(isaddr), 634 ifp->if_addrlen, 635 (u_char *)&la->ll_addr, ":", 636 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 637 ifp->if_xname); 638 } 639 } 640 641 if (ifp->if_addrlen != ah->ar_hln) { 642 log(LOG_WARNING, 643 "arp from %*D: addr len: new %d, i/f %d (ignored)", 644 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 645 ah->ar_hln, ifp->if_addrlen); 646 goto reply; 647 } 648 (void)memcpy(&la->ll_addr, ar_sha(ah), ifp->if_addrlen); 649 la->la_flags |= LLE_VALID; 650 651 if (!(la->la_flags & LLE_STATIC)) { 652 la->la_expire = time_uptime + V_arpt_keep; 653 callout_reset(&la->la_timer, hz * V_arpt_keep, 654 arptimer, la); 655 } 656 la->la_asked = 0; 657 la->la_preempt = V_arp_maxtries; 658 if (la->la_hold != NULL) { 659 m0 = la->la_hold; 660 la->la_hold = 0; 661 memcpy(&sa, L3_ADDR(la), sizeof(sa)); 662 LLE_WUNLOCK(la); 663 664 (*ifp->if_output)(ifp, m0, &sa, NULL); 665 return; 666 } 667 } 668reply: 669 if (op != ARPOP_REQUEST) 670 goto drop; 671 672 if (itaddr.s_addr == myaddr.s_addr) { 673 /* Shortcut.. the receiving interface is the target. */ 674 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 675 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln); 676 } else { 677 struct llentry *lle = NULL; 678 679 if (!V_arp_proxyall) 680 goto drop; 681 682 sin.sin_addr = itaddr; 683 /* XXX MRT use table 0 for arp reply */ 684 rt = in_rtalloc1((struct sockaddr *)&sin, 0, 0UL, 0); 685 if (!rt) 686 goto drop; 687 688 /* 689 * Don't send proxies for nodes on the same interface 690 * as this one came out of, or we'll get into a fight 691 * over who claims what Ether address. 692 */ 693 if (!rt->rt_ifp || rt->rt_ifp == ifp) { 694 RTFREE_LOCKED(rt); 695 goto drop; 696 } 697 IF_AFDATA_LOCK(rt->rt_ifp); 698 lle = lla_lookup(LLTABLE(rt->rt_ifp), 0, (struct sockaddr *)&sin); 699 IF_AFDATA_UNLOCK(rt->rt_ifp); 700 RTFREE_LOCKED(rt); 701 702 if (lle != NULL) { 703 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 704 (void)memcpy(ar_sha(ah), &lle->ll_addr, ah->ar_hln); 705 LLE_RUNLOCK(lle); 706 } else 707 goto drop; 708 709 /* 710 * Also check that the node which sent the ARP packet 711 * is on the the interface we expect it to be on. This 712 * avoids ARP chaos if an interface is connected to the 713 * wrong network. 714 */ 715 sin.sin_addr = isaddr; 716 717 /* XXX MRT use table 0 for arp checks */ 718 rt = in_rtalloc1((struct sockaddr *)&sin, 0, 0UL, 0); 719 if (!rt) 720 goto drop; 721 if (rt->rt_ifp != ifp) { 722 log(LOG_INFO, "arp_proxy: ignoring request" 723 " from %s via %s, expecting %s\n", 724 inet_ntoa(isaddr), ifp->if_xname, 725 rt->rt_ifp->if_xname); 726 RTFREE_LOCKED(rt); 727 goto drop; 728 } 729 RTFREE_LOCKED(rt); 730 731#ifdef DEBUG_PROXY 732 printf("arp: proxying for %s\n", 733 inet_ntoa(itaddr)); 734#endif 735 } 736 737 if (la != NULL) 738 LLE_WUNLOCK(la); 739 if (itaddr.s_addr == myaddr.s_addr && 740 IN_LINKLOCAL(ntohl(itaddr.s_addr))) { 741 /* RFC 3927 link-local IPv4; always reply by broadcast. */ 742#ifdef DEBUG_LINKLOCAL 743 printf("arp: sending reply for link-local addr %s\n", 744 inet_ntoa(itaddr)); 745#endif 746 m->m_flags |= M_BCAST; 747 m->m_flags &= ~M_MCAST; 748 } else { 749 /* default behaviour; never reply by broadcast. */ 750 m->m_flags &= ~(M_BCAST|M_MCAST); 751 } 752 (void)memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln); 753 (void)memcpy(ar_spa(ah), &itaddr, ah->ar_pln); 754 ah->ar_op = htons(ARPOP_REPLY); 755 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 756 m->m_len = sizeof(*ah) + (2 * ah->ar_pln) + (2 * ah->ar_hln); 757 m->m_pkthdr.len = m->m_len; 758 sa.sa_family = AF_ARP; 759 sa.sa_len = 2; 760 (*ifp->if_output)(ifp, m, &sa, NULL); 761 return; 762 763drop: 764 if (la != NULL) 765 LLE_WUNLOCK(la); 766 m_freem(m); 767} 768#endif 769 770void 771arp_ifinit(struct ifnet *ifp, struct ifaddr *ifa) 772{ 773 struct llentry *lle; 774 775 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY) { 776 arprequest(ifp, &IA_SIN(ifa)->sin_addr, 777 &IA_SIN(ifa)->sin_addr, IF_LLADDR(ifp)); 778 /* 779 * interface address is considered static entry 780 * because the output of the arp utility shows 781 * that L2 entry as permanent 782 */ 783 IF_AFDATA_LOCK(ifp); 784 lle = lla_lookup(LLTABLE(ifp), (LLE_CREATE | LLE_IFADDR | LLE_STATIC), 785 (struct sockaddr *)IA_SIN(ifa)); 786 IF_AFDATA_UNLOCK(ifp); 787 if (lle == NULL) 788 log(LOG_INFO, "arp_ifinit: cannot create arp " 789 "entry for interface address\n"); 790 else 791 LLE_RUNLOCK(lle); 792 } 793 ifa->ifa_rtrequest = NULL; 794} 795 796void 797arp_ifinit2(struct ifnet *ifp, struct ifaddr *ifa, u_char *enaddr) 798{ 799 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY) 800 arprequest(ifp, &IA_SIN(ifa)->sin_addr, 801 &IA_SIN(ifa)->sin_addr, enaddr); 802 ifa->ifa_rtrequest = NULL; 803} 804 805static int 806arp_iattach(const void *unused __unused) 807{ 808 INIT_VNET_INET(curvnet); 809 810 V_arpt_keep = (20*60); /* once resolved, good for 20 more minutes */ 811 V_arp_maxtries = 5; 812 V_useloopback = 1; /* use loopback interface for local traffic */ 813 V_arp_proxyall = 0; 814 815 return (0); 816} 817 818static void 819arp_init(void) 820{ 821 822#ifndef VIMAGE_GLOBALS 823 vnet_mod_register(&vnet_arp_modinfo); 824#else 825 arp_iattach(NULL); 826#endif 827 828 netisr_register(&arp_nh); 829} 830SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0); 831