1 /* 2 * Copyright (c) 2004, 2005 The DragonFly Project. All rights reserved. 3 * 4 * This code is derived from software contributed to The DragonFly Project 5 * by Jeffrey M. Hsu. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of The DragonFly Project nor the names of its 16 * contributors may be used to endorse or promote products derived 17 * from this software without specific, prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 21 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 22 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 23 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 24 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 25 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 26 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 27 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 28 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 29 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 /* 34 * Copyright (c) 1982, 1986, 1988, 1993 35 * The Regents of the University of California. All rights reserved. 36 * 37 * Redistribution and use in source and binary forms, with or without 38 * modification, are permitted provided that the following conditions 39 * are met: 40 * 1. Redistributions of source code must retain the above copyright 41 * notice, this list of conditions and the following disclaimer. 42 * 2. Redistributions in binary form must reproduce the above copyright 43 * notice, this list of conditions and the following disclaimer in the 44 * documentation and/or other materials provided with the distribution. 45 * 3. Neither the name of the University nor the names of its contributors 46 * may be used to endorse or promote products derived from this software 47 * without specific prior written permission. 48 * 49 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 50 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 51 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 52 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 53 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 54 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 55 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 56 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 57 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 58 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 59 * SUCH DAMAGE. 60 * 61 * @(#)if_ether.c 8.1 (Berkeley) 6/10/93 62 * $FreeBSD: src/sys/netinet/if_ether.c,v 1.64.2.23 2003/04/11 07:23:15 fjoe Exp $ 63 */ 64 65 /* 66 * Ethernet address resolution protocol. 67 * TODO: 68 * add "inuse/lock" bit (or ref. count) along with valid bit 69 */ 70 71 #include "opt_inet.h" 72 #include "opt_carp.h" 73 74 #include <sys/param.h> 75 #include <sys/kernel.h> 76 #include <sys/queue.h> 77 #include <sys/sysctl.h> 78 #include <sys/systm.h> 79 #include <sys/mbuf.h> 80 #include <sys/malloc.h> 81 #include <sys/socket.h> 82 #include <sys/syslog.h> 83 #include <sys/lock.h> 84 85 #include <net/if.h> 86 #include <net/if_dl.h> 87 #include <net/if_types.h> 88 #include <net/route.h> 89 #include <net/netisr.h> 90 #include <net/if_llc.h> 91 92 #include <netinet/in.h> 93 #include <netinet/in_var.h> 94 #include <netinet/if_ether.h> 95 96 #include <sys/thread2.h> 97 #include <sys/msgport2.h> 98 #include <net/netmsg2.h> 99 #include <net/netisr2.h> 100 #include <sys/mplock2.h> 101 102 #ifdef CARP 103 #include <netinet/ip_carp.h> 104 #endif 105 106 #define SIN(s) ((struct sockaddr_in *)s) 107 #define SDL(s) ((struct sockaddr_dl *)s) 108 109 SYSCTL_DECL(_net_link_ether); 110 SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, ""); 111 112 /* timer values */ 113 static int arpt_prune = (5*60*1); /* walk list every 5 minutes */ 114 static int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */ 115 static int arpt_down = 20; /* once declared down, don't send for 20 sec */ 116 117 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, prune_intvl, CTLFLAG_RW, 118 &arpt_prune, 0, ""); 119 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW, 120 &arpt_keep, 0, ""); 121 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, host_down_time, CTLFLAG_RW, 122 &arpt_down, 0, ""); 123 124 #define rt_expire rt_rmx.rmx_expire 125 126 struct llinfo_arp { 127 LIST_ENTRY(llinfo_arp) la_le; 128 struct rtentry *la_rt; 129 struct mbuf *la_hold; /* last packet until resolved/timeout */ 130 u_short la_preempt; /* countdown for pre-expiry arps */ 131 u_short la_asked; /* #times we QUERIED following expiration */ 132 }; 133 134 static LIST_HEAD(, llinfo_arp) llinfo_arp_list[MAXCPU]; 135 136 static int arp_maxtries = 5; 137 static int useloopback = 1; /* use loopback interface for local traffic */ 138 static int arp_proxyall = 0; 139 static int arp_refresh = 60; /* refresh arp cache ~60 (not impl yet) */ 140 static int arp_restricted_match = 0; 141 142 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW, 143 &arp_maxtries, 0, "ARP resolution attempts before returning error"); 144 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW, 145 &useloopback, 0, "Use the loopback interface for local traffic"); 146 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW, 147 &arp_proxyall, 0, "Enable proxy ARP for all suitable requests"); 148 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, restricted_match, CTLFLAG_RW, 149 &arp_restricted_match, 0, "Only match against the sender"); 150 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, refresh, CTLFLAG_RW, 151 &arp_refresh, 0, "Preemptively refresh the ARP"); 152 153 static void arp_rtrequest(int, struct rtentry *); 154 static void arprequest(struct ifnet *, const struct in_addr *, 155 const struct in_addr *, const u_char *); 156 static void arprequest_async(struct ifnet *, const struct in_addr *, 157 const struct in_addr *, const u_char *); 158 static void arpintr(netmsg_t msg); 159 static void arptfree(struct llinfo_arp *); 160 static void arptimer(void *); 161 static struct llinfo_arp * 162 arplookup(in_addr_t, boolean_t, boolean_t, boolean_t); 163 #ifdef INET 164 static void in_arpinput(struct mbuf *); 165 static void in_arpreply(struct mbuf *m, in_addr_t, in_addr_t); 166 static void arp_update_msghandler(netmsg_t); 167 static void arp_reply_msghandler(netmsg_t); 168 #endif 169 170 struct arptimer_ctx { 171 struct callout timer_ch; 172 struct netmsg_base timer_nmsg; 173 int timer_inited; 174 } __cachealign; 175 176 static struct arptimer_ctx arptimer_context[MAXCPU]; 177 178 /* 179 * Timeout routine. Age arp_tab entries periodically. 180 */ 181 static void 182 arptimer_dispatch(netmsg_t nmsg) 183 { 184 struct llinfo_arp *la, *nla; 185 int cpuid = mycpuid; 186 187 /* Reply ASAP */ 188 crit_enter(); 189 lwkt_replymsg(&nmsg->lmsg, 0); 190 crit_exit(); 191 192 LIST_FOREACH_MUTABLE(la, &llinfo_arp_list[cpuid], la_le, nla) { 193 if (la->la_rt->rt_expire && la->la_rt->rt_expire <= time_uptime) 194 arptfree(la); 195 } 196 callout_reset(&arptimer_context[cpuid].timer_ch, arpt_prune * hz, 197 arptimer, NULL); 198 } 199 200 static void 201 arptimer(void *arg __unused) 202 { 203 int cpuid = mycpuid; 204 struct lwkt_msg *lmsg = &arptimer_context[cpuid].timer_nmsg.lmsg; 205 206 crit_enter(); 207 if (lmsg->ms_flags & MSGF_DONE) 208 lwkt_sendmsg_oncpu(netisr_cpuport(cpuid), lmsg); 209 crit_exit(); 210 } 211 212 /* 213 * Parallel to llc_rtrequest. 214 * 215 * Called after a route is successfully added to the tree to fix-up the 216 * route and initiate arp operations if required. 217 */ 218 static void 219 arp_rtrequest(int req, struct rtentry *rt) 220 { 221 struct sockaddr *gate = rt->rt_gateway; 222 struct llinfo_arp *la = rt->rt_llinfo; 223 224 struct sockaddr_dl null_sdl = { sizeof null_sdl, AF_LINK }; 225 226 if (__predict_false(!arptimer_context[mycpuid].timer_inited)) { 227 struct arptimer_ctx *ctx = &arptimer_context[mycpuid]; 228 229 ctx->timer_inited = TRUE; 230 netmsg_init(&ctx->timer_nmsg, NULL, &netisr_adone_rport, 231 MSGF_PRIORITY, arptimer_dispatch); 232 callout_init_mp(&ctx->timer_ch); 233 callout_reset(&ctx->timer_ch, hz, arptimer, NULL); 234 } 235 if (rt->rt_flags & RTF_GATEWAY) 236 return; 237 238 switch (req) { 239 case RTM_ADD: 240 /* 241 * XXX: If this is a manually added route to interface 242 * such as older version of routed or gated might provide, 243 * restore cloning bit. 244 */ 245 if (!(rt->rt_flags & RTF_HOST) && 246 SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff) 247 rt->rt_flags |= RTF_CLONING; 248 if (rt->rt_flags & RTF_CLONING) { 249 /* 250 * Case 1: This route should come from a route to iface. 251 */ 252 rt_setgate(rt, rt_key(rt), 253 (struct sockaddr *)&null_sdl, 254 RTL_DONTREPORT); 255 gate = rt->rt_gateway; 256 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 257 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 258 rt->rt_expire = time_uptime; 259 break; 260 } 261 /* Announce a new entry if requested. */ 262 if (rt->rt_flags & RTF_ANNOUNCE) { 263 arprequest_async(rt->rt_ifp, 264 &SIN(rt_key(rt))->sin_addr, 265 &SIN(rt_key(rt))->sin_addr, 266 LLADDR(SDL(gate))); 267 } 268 /*FALLTHROUGH*/ 269 case RTM_RESOLVE: 270 if (gate->sa_family != AF_LINK || 271 gate->sa_len < sizeof(struct sockaddr_dl)) { 272 log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n"); 273 break; 274 } 275 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 276 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 277 if (la != NULL) 278 break; /* This happens on a route change */ 279 /* 280 * Case 2: This route may come from cloning, or a manual route 281 * add with a LL address. 282 */ 283 R_Malloc(la, struct llinfo_arp *, sizeof *la); 284 rt->rt_llinfo = la; 285 if (la == NULL) { 286 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); 287 break; 288 } 289 bzero(la, sizeof *la); 290 la->la_rt = rt; 291 rt->rt_flags |= RTF_LLINFO; 292 LIST_INSERT_HEAD(&llinfo_arp_list[mycpuid], la, la_le); 293 294 #ifdef INET 295 /* 296 * This keeps the multicast addresses from showing up 297 * in `arp -a' listings as unresolved. It's not actually 298 * functional. Then the same for broadcast. 299 */ 300 if (IN_MULTICAST(ntohl(SIN(rt_key(rt))->sin_addr.s_addr))) { 301 ETHER_MAP_IP_MULTICAST(&SIN(rt_key(rt))->sin_addr, 302 LLADDR(SDL(gate))); 303 SDL(gate)->sdl_alen = 6; 304 rt->rt_expire = 0; 305 } 306 if (in_broadcast(SIN(rt_key(rt))->sin_addr, rt->rt_ifp)) { 307 memcpy(LLADDR(SDL(gate)), rt->rt_ifp->if_broadcastaddr, 308 rt->rt_ifp->if_addrlen); 309 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen; 310 rt->rt_expire = 0; 311 } 312 #endif 313 314 /* 315 * This fixes up the routing interface for local addresses. 316 * The route is adjusted to point at lo0 and the expiration 317 * timer is disabled. 318 * 319 * NOTE: This prevents locally targetted traffic from going 320 * out the hardware interface, which is inefficient 321 * and might not work if the hardware cannot listen 322 * to its own transmitted packets. Setting 323 * net.link.ether.inet.useloopback to 0 will force 324 * packets for local addresses out the hardware (and 325 * it is expected to receive its own packet). 326 * 327 * XXX We should just be able to test RTF_LOCAL here instead 328 * of having to compare IPs. 329 */ 330 if (SIN(rt_key(rt))->sin_addr.s_addr == 331 (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) { 332 rt->rt_expire = 0; 333 bcopy(IF_LLADDR(rt->rt_ifp), LLADDR(SDL(gate)), 334 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen); 335 if (useloopback) 336 rt->rt_ifp = loif; 337 } 338 break; 339 340 case RTM_DELETE: 341 if (la == NULL) 342 break; 343 LIST_REMOVE(la, la_le); 344 rt->rt_llinfo = NULL; 345 rt->rt_flags &= ~RTF_LLINFO; 346 if (la->la_hold != NULL) 347 m_freem(la->la_hold); 348 Free(la); 349 break; 350 } 351 } 352 353 static struct mbuf * 354 arpreq_alloc(struct ifnet *ifp, const struct in_addr *sip, 355 const struct in_addr *tip, const u_char *enaddr) 356 { 357 struct mbuf *m; 358 struct arphdr *ah; 359 u_short ar_hrd; 360 361 if ((m = m_gethdr(M_NOWAIT, MT_DATA)) == NULL) 362 return NULL; 363 m->m_pkthdr.rcvif = NULL; 364 365 switch (ifp->if_type) { 366 case IFT_ETHER: 367 /* 368 * This may not be correct for types not explicitly 369 * listed, but this is our best guess 370 */ 371 default: 372 ar_hrd = htons(ARPHRD_ETHER); 373 374 m->m_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 375 m->m_pkthdr.len = m->m_len; 376 MH_ALIGN(m, m->m_len); 377 378 ah = mtod(m, struct arphdr *); 379 break; 380 } 381 382 ah->ar_hrd = ar_hrd; 383 ah->ar_pro = htons(ETHERTYPE_IP); 384 ah->ar_hln = ifp->if_addrlen; /* hardware address length */ 385 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 386 ah->ar_op = htons(ARPOP_REQUEST); 387 memcpy(ar_sha(ah), enaddr, ah->ar_hln); 388 memset(ar_tha(ah), 0, ah->ar_hln); 389 memcpy(ar_spa(ah), sip, ah->ar_pln); 390 memcpy(ar_tpa(ah), tip, ah->ar_pln); 391 392 return m; 393 } 394 395 static void 396 arpreq_send(struct ifnet *ifp, struct mbuf *m) 397 { 398 struct sockaddr sa; 399 struct ether_header *eh; 400 401 switch (ifp->if_type) { 402 case IFT_ETHER: 403 /* 404 * This may not be correct for types not explicitly 405 * listed, but this is our best guess 406 */ 407 default: 408 eh = (struct ether_header *)sa.sa_data; 409 /* if_output() will not swap */ 410 eh->ether_type = htons(ETHERTYPE_ARP); 411 memcpy(eh->ether_dhost, ifp->if_broadcastaddr, ifp->if_addrlen); 412 break; 413 } 414 415 sa.sa_family = AF_UNSPEC; 416 sa.sa_len = sizeof(sa); 417 ifp->if_output(ifp, m, &sa, NULL); 418 } 419 420 static void 421 arpreq_send_handler(netmsg_t msg) 422 { 423 struct mbuf *m = msg->packet.nm_packet; 424 struct ifnet *ifp = msg->lmsg.u.ms_resultp; 425 426 arpreq_send(ifp, m); 427 /* nmsg was embedded in the mbuf, do not reply! */ 428 } 429 430 /* 431 * Broadcast an ARP request. Caller specifies: 432 * - arp header source ip address 433 * - arp header target ip address 434 * - arp header source ethernet address 435 * 436 * NOTE: Caller MUST NOT hold ifp's serializer 437 */ 438 static void 439 arprequest(struct ifnet *ifp, const struct in_addr *sip, 440 const struct in_addr *tip, const u_char *enaddr) 441 { 442 struct mbuf *m; 443 444 if (enaddr == NULL) { 445 if (ifp->if_bridge) { 446 enaddr = IF_LLADDR(ether_bridge_interface(ifp)); 447 } else { 448 enaddr = IF_LLADDR(ifp); 449 } 450 } 451 452 m = arpreq_alloc(ifp, sip, tip, enaddr); 453 if (m == NULL) 454 return; 455 arpreq_send(ifp, m); 456 } 457 458 /* 459 * Same as arprequest(), except: 460 * - Caller is allowed to hold ifp's serializer 461 * - Network output is done in protocol thead 462 */ 463 static void 464 arprequest_async(struct ifnet *ifp, const struct in_addr *sip, 465 const struct in_addr *tip, const u_char *enaddr) 466 { 467 struct mbuf *m; 468 struct netmsg_packet *pmsg; 469 470 if (enaddr == NULL) { 471 if (ifp->if_bridge) { 472 enaddr = IF_LLADDR(ether_bridge_interface(ifp)); 473 } else { 474 enaddr = IF_LLADDR(ifp); 475 } 476 } 477 m = arpreq_alloc(ifp, sip, tip, enaddr); 478 if (m == NULL) 479 return; 480 481 pmsg = &m->m_hdr.mh_netmsg; 482 netmsg_init(&pmsg->base, NULL, &netisr_apanic_rport, 483 0, arpreq_send_handler); 484 pmsg->nm_packet = m; 485 pmsg->base.lmsg.u.ms_resultp = ifp; 486 487 lwkt_sendmsg_oncpu(netisr_cpuport(mycpuid), &pmsg->base.lmsg); 488 } 489 490 /* 491 * Resolve an IP address into an ethernet address. If success, 492 * desten is filled in. If there is no entry in arptab, 493 * set one up and broadcast a request for the IP address. 494 * Hold onto this mbuf and resend it once the address 495 * is finally resolved. A return value of 1 indicates 496 * that desten has been filled in and the packet should be sent 497 * normally; a 0 return indicates that the packet has been 498 * taken over here, either now or for later transmission. 499 */ 500 int 501 arpresolve(struct ifnet *ifp, struct rtentry *rt0, struct mbuf *m, 502 struct sockaddr *dst, u_char *desten) 503 { 504 struct rtentry *rt = NULL; 505 struct llinfo_arp *la = NULL; 506 struct sockaddr_dl *sdl; 507 508 if (m->m_flags & M_BCAST) { /* broadcast */ 509 memcpy(desten, ifp->if_broadcastaddr, ifp->if_addrlen); 510 return (1); 511 } 512 if (m->m_flags & M_MCAST) {/* multicast */ 513 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); 514 return (1); 515 } 516 if (rt0 != NULL) { 517 if (rt_llroute(dst, rt0, &rt) != 0) { 518 m_freem(m); 519 return 0; 520 } 521 la = rt->rt_llinfo; 522 } 523 if (la == NULL) { 524 la = arplookup(SIN(dst)->sin_addr.s_addr, 525 TRUE, RTL_REPORTMSG, FALSE); 526 if (la != NULL) 527 rt = la->la_rt; 528 } 529 if (la == NULL || rt == NULL) { 530 log(LOG_DEBUG, "arpresolve: can't allocate llinfo for %s%s%s\n", 531 inet_ntoa(SIN(dst)->sin_addr), la ? "la" : " ", 532 rt ? "rt" : ""); 533 m_freem(m); 534 return (0); 535 } 536 sdl = SDL(rt->rt_gateway); 537 /* 538 * Check the address family and length is valid, the address 539 * is resolved; otherwise, try to resolve. 540 */ 541 if ((rt->rt_expire == 0 || rt->rt_expire > time_uptime) && 542 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 543 /* 544 * If entry has an expiry time and it is approaching, 545 * see if we need to send an ARP request within this 546 * arpt_down interval. 547 */ 548 if ((rt->rt_expire != 0) && 549 (time_uptime + la->la_preempt > rt->rt_expire)) { 550 arprequest(ifp, 551 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 552 &SIN(dst)->sin_addr, 553 NULL); 554 la->la_preempt--; 555 } 556 557 bcopy(LLADDR(sdl), desten, sdl->sdl_alen); 558 return 1; 559 } 560 /* 561 * If ARP is disabled or static on this interface, stop. 562 * XXX 563 * Probably should not allocate empty llinfo struct if we are 564 * not going to be sending out an arp request. 565 */ 566 if (ifp->if_flags & (IFF_NOARP | IFF_STATICARP)) { 567 m_freem(m); 568 return (0); 569 } 570 /* 571 * There is an arptab entry, but no ethernet address 572 * response yet. Replace the held mbuf with this 573 * latest one. 574 */ 575 if (la->la_hold != NULL) 576 m_freem(la->la_hold); 577 la->la_hold = m; 578 if (rt->rt_expire || ((rt->rt_flags & RTF_STATIC) && !sdl->sdl_alen)) { 579 rt->rt_flags &= ~RTF_REJECT; 580 if (la->la_asked == 0 || rt->rt_expire != time_uptime) { 581 rt->rt_expire = time_uptime; 582 if (la->la_asked++ < arp_maxtries) { 583 arprequest(ifp, 584 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 585 &SIN(dst)->sin_addr, 586 NULL); 587 } else { 588 rt->rt_flags |= RTF_REJECT; 589 rt->rt_expire += arpt_down; 590 la->la_asked = 0; 591 la->la_preempt = arp_maxtries; 592 } 593 } 594 } 595 return (0); 596 } 597 598 /* 599 * Common length and type checks are done here, 600 * then the protocol-specific routine is called. 601 */ 602 static void 603 arpintr(netmsg_t msg) 604 { 605 struct mbuf *m = msg->packet.nm_packet; 606 struct arphdr *ar; 607 u_short ar_hrd; 608 char hexstr[6]; 609 610 if (m->m_len < sizeof(struct arphdr) && 611 (m = m_pullup(m, sizeof(struct arphdr))) == NULL) { 612 log(LOG_ERR, "arp: runt packet -- m_pullup failed\n"); 613 return; 614 } 615 ar = mtod(m, struct arphdr *); 616 617 ar_hrd = ntohs(ar->ar_hrd); 618 if (ar_hrd != ARPHRD_ETHER && ar_hrd != ARPHRD_IEEE802) { 619 hexncpy((unsigned char *)&ar->ar_hrd, 2, hexstr, 5, NULL); 620 log(LOG_ERR, "arp: unknown hardware address format (0x%s)\n", 621 hexstr); 622 m_freem(m); 623 return; 624 } 625 626 if (m->m_pkthdr.len < arphdr_len(ar)) { 627 if ((m = m_pullup(m, arphdr_len(ar))) == NULL) { 628 log(LOG_ERR, "arp: runt packet\n"); 629 return; 630 } 631 ar = mtod(m, struct arphdr *); 632 } 633 634 switch (ntohs(ar->ar_pro)) { 635 #ifdef INET 636 case ETHERTYPE_IP: 637 in_arpinput(m); 638 return; 639 #endif 640 } 641 m_freem(m); 642 /* msg was embedded in the mbuf, do not reply! */ 643 } 644 645 #ifdef INET 646 /* 647 * ARP for Internet protocols on 10 Mb/s Ethernet. 648 * Algorithm is that given in RFC 826. 649 * In addition, a sanity check is performed on the sender 650 * protocol address, to catch impersonators. 651 * We no longer handle negotiations for use of trailer protocol: 652 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 653 * along with IP replies if we wanted trailers sent to us, 654 * and also sent them in response to IP replies. 655 * This allowed either end to announce the desire to receive 656 * trailer packets. 657 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 658 * but formerly didn't normally send requests. 659 */ 660 661 static int log_arp_wrong_iface = 1; 662 static int log_arp_movements = 1; 663 static int log_arp_permanent_modify = 1; 664 static int log_arp_creation_failure = 1; 665 666 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW, 667 &log_arp_wrong_iface, 0, 668 "Log arp packets arriving on the wrong interface"); 669 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_movements, CTLFLAG_RW, 670 &log_arp_movements, 0, 671 "Log arp replies from MACs different than the one in the cache"); 672 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_permanent_modify, CTLFLAG_RW, 673 &log_arp_permanent_modify, 0, 674 "Log arp replies from MACs different than the one " 675 "in the permanent arp entry"); 676 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_creation_failure, CTLFLAG_RW, 677 &log_arp_creation_failure, 0, "Log arp creation failure"); 678 679 static void 680 arp_update_oncpu(struct mbuf *m, in_addr_t saddr, boolean_t create, 681 boolean_t generate_report, boolean_t dologging) 682 { 683 struct arphdr *ah = mtod(m, struct arphdr *); 684 struct ifnet *ifp = m->m_pkthdr.rcvif; 685 struct llinfo_arp *la; 686 struct sockaddr_dl *sdl; 687 struct rtentry *rt; 688 char hexstr[2][64]; 689 690 KASSERT(curthread->td_type == TD_TYPE_NETISR, 691 ("arp update not in netisr")); 692 693 la = arplookup(saddr, create, generate_report, FALSE); 694 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { 695 struct in_addr isaddr = { saddr }; 696 697 /* 698 * Normally arps coming in on the wrong interface are ignored, 699 * but if we are bridging and the two interfaces belong to 700 * the same bridge, or one is a member of the bridge which 701 * is the other, then it isn't an error. 702 */ 703 if (rt->rt_ifp != ifp) { 704 /* 705 * (1) ifp and rt_ifp both members of same bridge 706 * (2) rt_ifp member of bridge ifp 707 * (3) ifp member of bridge rt_ifp 708 * 709 * Always replace rt_ifp with the bridge ifc. 710 */ 711 struct ifnet *nifp; 712 713 if (ifp->if_bridge && 714 rt->rt_ifp->if_bridge == ifp->if_bridge) { 715 nifp = ether_bridge_interface(ifp); 716 } else if (rt->rt_ifp->if_bridge && 717 ether_bridge_interface(rt->rt_ifp) == ifp) { 718 nifp = ifp; 719 } else if (ifp->if_bridge && 720 ether_bridge_interface(ifp) == rt->rt_ifp) { 721 nifp = rt->rt_ifp; 722 } else { 723 nifp = NULL; 724 } 725 726 if ((log_arp_wrong_iface == 1 && nifp == NULL) || 727 log_arp_wrong_iface == 2) { 728 hexncpy((u_char *)ar_sha(ah), ifp->if_addrlen, 729 hexstr[0], HEX_NCPYLEN(ifp->if_addrlen), ":"); 730 log(LOG_ERR, 731 "arp: %s is on %s " 732 "but got reply from %s on %s\n", 733 inet_ntoa(isaddr), 734 rt->rt_ifp->if_xname, hexstr[0], 735 ifp->if_xname); 736 } 737 if (nifp == NULL) 738 return; 739 740 /* 741 * nifp is our man! Replace rt_ifp and adjust 742 * the sdl. 743 */ 744 ifp = rt->rt_ifp = nifp; 745 sdl->sdl_type = ifp->if_type; 746 sdl->sdl_index = ifp->if_index; 747 } 748 if (sdl->sdl_alen && 749 bcmp(ar_sha(ah), LLADDR(sdl), sdl->sdl_alen)) { 750 if (rt->rt_expire != 0) { 751 if (dologging && log_arp_movements) { 752 hexncpy((u_char *)LLADDR(sdl), ifp->if_addrlen, 753 hexstr[0], HEX_NCPYLEN(ifp->if_addrlen), ":"); 754 hexncpy((u_char *)ar_sha(ah), ifp->if_addrlen, 755 hexstr[1], HEX_NCPYLEN(ifp->if_addrlen), ":"); 756 log(LOG_INFO, 757 "arp: %s moved from %s to %s on %s\n", 758 inet_ntoa(isaddr), hexstr[0], hexstr[1], 759 ifp->if_xname); 760 } 761 } else { 762 if (dologging && log_arp_permanent_modify) { 763 hexncpy((u_char *)ar_sha(ah), ifp->if_addrlen, 764 hexstr[0], HEX_NCPYLEN(ifp->if_addrlen), ":"); 765 log(LOG_ERR, 766 "arp: %s attempts to modify " 767 "permanent entry for %s on %s\n", 768 hexstr[0], inet_ntoa(isaddr), ifp->if_xname); 769 } 770 return; 771 } 772 } 773 /* 774 * sanity check for the address length. 775 * XXX this does not work for protocols with variable address 776 * length. -is 777 */ 778 if (dologging && sdl->sdl_alen && sdl->sdl_alen != ah->ar_hln) { 779 hexncpy((u_char *)ar_sha(ah), ifp->if_addrlen, 780 hexstr[0], HEX_NCPYLEN(ifp->if_addrlen), ":"); 781 log(LOG_WARNING, 782 "arp from %s: new addr len %d, was %d", 783 hexstr[0], ah->ar_hln, sdl->sdl_alen); 784 } 785 if (ifp->if_addrlen != ah->ar_hln) { 786 if (dologging) { 787 hexncpy((u_char *)ar_sha(ah), ifp->if_addrlen, 788 hexstr[0], HEX_NCPYLEN(ifp->if_addrlen), ":"); 789 log(LOG_WARNING, 790 "arp from %s: addr len: new %d, i/f %d " 791 "(ignored)", hexstr[0], 792 ah->ar_hln, ifp->if_addrlen); 793 } 794 return; 795 } 796 memcpy(LLADDR(sdl), ar_sha(ah), sdl->sdl_alen = ah->ar_hln); 797 if (rt->rt_expire != 0) { 798 rt->rt_expire = time_uptime + arpt_keep; 799 } 800 rt->rt_flags &= ~RTF_REJECT; 801 la->la_asked = 0; 802 la->la_preempt = arp_maxtries; 803 804 /* 805 * This particular cpu might have been holding an mbuf 806 * pending ARP resolution. If so, transmit the mbuf now. 807 */ 808 if (la->la_hold != NULL) { 809 struct mbuf *m = la->la_hold; 810 811 la->la_hold = NULL; 812 m_adj(m, sizeof(struct ether_header)); 813 ifp->if_output(ifp, m, rt_key(rt), rt); 814 } 815 } 816 } 817 818 /* 819 * Called from arpintr() - this routine is run from a single cpu. 820 */ 821 static void 822 in_arpinput(struct mbuf *m) 823 { 824 struct arphdr *ah; 825 struct ifnet *ifp = m->m_pkthdr.rcvif; 826 struct ifaddr_container *ifac; 827 struct in_ifaddr_container *iac; 828 struct in_ifaddr *ia = NULL; 829 struct in_addr isaddr, itaddr, myaddr; 830 uint8_t *enaddr = NULL; 831 int req_len; 832 char hexstr[64]; 833 834 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 835 if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) { 836 log(LOG_ERR, "in_arp: runt packet -- m_pullup failed\n"); 837 return; 838 } 839 840 ah = mtod(m, struct arphdr *); 841 memcpy(&isaddr, ar_spa(ah), sizeof isaddr); 842 memcpy(&itaddr, ar_tpa(ah), sizeof itaddr); 843 844 /* 845 * Check both target and sender IP addresses: 846 * 847 * If we receive the packet on the interface owning the address, 848 * then accept the address. 849 * 850 * For a bridge, we accept the address if the receive interface and 851 * the interface owning the address are on the same bridge, and 852 * use the bridge MAC as the is-at response. The bridge will be 853 * responsible for handling the packet. 854 * 855 * (0) Check target IP against CARP IPs 856 */ 857 #ifdef CARP 858 LIST_FOREACH(iac, INADDR_HASH(itaddr.s_addr), ia_hash) { 859 int is_match = 0, is_parent = 0; 860 861 ia = iac->ia; 862 863 /* Skip all ia's which don't match */ 864 if (itaddr.s_addr != ia->ia_addr.sin_addr.s_addr) 865 continue; 866 867 if (ia->ia_ifp->if_type != IFT_CARP) 868 continue; 869 870 if (carp_parent(ia->ia_ifp) == ifp) 871 is_parent = 1; 872 if (is_parent || ia->ia_ifp == ifp) 873 is_match = carp_iamatch(ia); 874 875 if (is_match) { 876 if (is_parent) { 877 /* 878 * The parent interface will also receive 879 * the ethernet broadcast packets, e.g. ARP 880 * REQUEST, so if we could find a CARP 881 * interface of the parent that could match 882 * the target IP address, we then drop the 883 * packets, which is delieverd to us through 884 * the parent interface. 885 */ 886 m_freem(m); 887 return; 888 } 889 goto match; 890 } 891 } 892 #endif /* CARP */ 893 894 /* 895 * (1) Check target IP against our local IPs 896 */ 897 LIST_FOREACH(iac, INADDR_HASH(itaddr.s_addr), ia_hash) { 898 ia = iac->ia; 899 900 /* Skip all ia's which don't match */ 901 if (itaddr.s_addr != ia->ia_addr.sin_addr.s_addr) 902 continue; 903 904 #ifdef CARP 905 /* CARP interfaces are checked in (0) */ 906 if (ia->ia_ifp->if_type == IFT_CARP) 907 continue; 908 #endif 909 910 if (ifp->if_bridge && ia->ia_ifp && 911 ifp->if_bridge == ia->ia_ifp->if_bridge) { 912 ifp = ether_bridge_interface(ifp); 913 goto match; 914 } 915 if (ia->ia_ifp && ia->ia_ifp->if_bridge && 916 ether_bridge_interface(ia->ia_ifp) == ifp) { 917 goto match; 918 } 919 if (ifp->if_bridge && ether_bridge_interface(ifp) == 920 ia->ia_ifp) { 921 goto match; 922 } 923 if (ia->ia_ifp == ifp) { 924 goto match; 925 } 926 } 927 928 /* 929 * (2) Check sender IP against our local IPs 930 */ 931 LIST_FOREACH(iac, INADDR_HASH(isaddr.s_addr), ia_hash) { 932 ia = iac->ia; 933 934 /* Skip all ia's which don't match */ 935 if (isaddr.s_addr != ia->ia_addr.sin_addr.s_addr) 936 continue; 937 938 if (ifp->if_bridge && ia->ia_ifp && 939 ifp->if_bridge == ia->ia_ifp->if_bridge) { 940 ifp = ether_bridge_interface(ifp); 941 goto match; 942 } 943 if (ia->ia_ifp && ia->ia_ifp->if_bridge && 944 ether_bridge_interface(ia->ia_ifp) == ifp) { 945 goto match; 946 } 947 if (ifp->if_bridge && ether_bridge_interface(ifp) == 948 ia->ia_ifp) { 949 goto match; 950 } 951 952 if (ia->ia_ifp == ifp) 953 goto match; 954 } 955 956 /* 957 * No match, use the first inet address on the receive interface 958 * as a dummy address for the rest of the function. 959 */ 960 TAILQ_FOREACH(ifac, &ifp->if_addrheads[mycpuid], ifa_link) { 961 struct ifaddr *ifa = ifac->ifa; 962 963 if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_INET) { 964 ia = ifatoia(ifa); 965 goto match; 966 } 967 } 968 969 /* 970 * If we got here, we didn't find any suitable interface, 971 * so drop the packet. 972 */ 973 m_freem(m); 974 return; 975 976 match: 977 if (!enaddr) 978 enaddr = (uint8_t *)IF_LLADDR(ifp); 979 myaddr = ia->ia_addr.sin_addr; 980 if (!bcmp(ar_sha(ah), enaddr, ifp->if_addrlen)) { 981 m_freem(m); /* it's from me, ignore it. */ 982 return; 983 } 984 if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) { 985 log(LOG_ERR, 986 "arp: link address is broadcast for IP address %s!\n", 987 inet_ntoa(isaddr)); 988 m_freem(m); 989 return; 990 } 991 if (isaddr.s_addr == myaddr.s_addr && myaddr.s_addr != 0) { 992 hexncpy((u_char *)ar_sha(ah), ifp->if_addrlen, 993 hexstr, HEX_NCPYLEN(ifp->if_addrlen), ":"); 994 log(LOG_ERR, 995 "arp: %s is using my IP address %s!\n", 996 hexstr, inet_ntoa(isaddr)); 997 itaddr = myaddr; 998 goto reply; 999 } 1000 if (ifp->if_flags & IFF_STATICARP) 1001 goto reply; 1002 1003 /* 1004 * When arp_restricted_match is true and the ARP response is not 1005 * specifically targetted to me, ignore it. Otherwise the entry 1006 * timeout may be updated for an old MAC. 1007 */ 1008 if (arp_restricted_match && itaddr.s_addr != myaddr.s_addr) { 1009 m_freem(m); 1010 return; 1011 } 1012 1013 /* 1014 * Update all CPU's routing tables with this ARP packet. 1015 * 1016 * However, we only need to generate rtmsg on CPU0. 1017 */ 1018 KASSERT(&curthread->td_msgport == netisr_cpuport(0), 1019 ("arp input not in netisr0, but on cpu%d", mycpuid)); 1020 arp_update_oncpu(m, isaddr.s_addr, itaddr.s_addr == myaddr.s_addr, 1021 RTL_REPORTMSG, TRUE); 1022 1023 if (ncpus > 1) { 1024 struct netmsg_inarp *msg = &m->m_hdr.mh_arpmsg; 1025 1026 netmsg_init(&msg->base, NULL, &netisr_apanic_rport, 1027 0, arp_update_msghandler); 1028 msg->m = m; 1029 msg->saddr = isaddr.s_addr; 1030 msg->taddr = itaddr.s_addr; 1031 msg->myaddr = myaddr.s_addr; 1032 lwkt_sendmsg(netisr_cpuport(1), &msg->base.lmsg); 1033 } else { 1034 goto reply; 1035 } 1036 1037 /* 1038 * Just return here; after all CPUs's routing tables are 1039 * properly updated by this ARP packet, an ARP reply will 1040 * be generated if appropriate. 1041 */ 1042 return; 1043 reply: 1044 in_arpreply(m, itaddr.s_addr, myaddr.s_addr); 1045 } 1046 1047 static void 1048 arp_reply_msghandler(netmsg_t msg) 1049 { 1050 struct netmsg_inarp *rmsg = (struct netmsg_inarp *)msg; 1051 1052 in_arpreply(rmsg->m, rmsg->taddr, rmsg->myaddr); 1053 /* Don't reply this netmsg; netmsg_inarp is embedded in mbuf */ 1054 } 1055 1056 static void 1057 arp_update_msghandler(netmsg_t msg) 1058 { 1059 struct netmsg_inarp *rmsg = (struct netmsg_inarp *)msg; 1060 int nextcpu; 1061 1062 /* 1063 * This message handler will be called on all of the APs; 1064 * no need to generate rtmsg on them. 1065 */ 1066 KASSERT(mycpuid > 0, ("arp update msg on cpu%d", mycpuid)); 1067 arp_update_oncpu(rmsg->m, rmsg->saddr, rmsg->taddr == rmsg->myaddr, 1068 RTL_DONTREPORT, FALSE); 1069 1070 nextcpu = mycpuid + 1; 1071 if (nextcpu < ncpus) { 1072 lwkt_forwardmsg(netisr_cpuport(nextcpu), &rmsg->base.lmsg); 1073 } else { 1074 struct mbuf *m = rmsg->m; 1075 in_addr_t saddr = rmsg->saddr; 1076 in_addr_t taddr = rmsg->taddr; 1077 in_addr_t myaddr = rmsg->myaddr; 1078 1079 /* 1080 * Dispatch this mbuf to netisr0 to perform ARP reply, 1081 * if appropriate. 1082 * NOTE: netmsg_inarp is embedded in this mbuf. 1083 */ 1084 netmsg_init(&rmsg->base, NULL, &netisr_apanic_rport, 1085 0, arp_reply_msghandler); 1086 rmsg->m = m; 1087 rmsg->saddr = saddr; 1088 rmsg->taddr = taddr; 1089 rmsg->myaddr = myaddr; 1090 lwkt_sendmsg(netisr_cpuport(0), &rmsg->base.lmsg); 1091 } 1092 } 1093 1094 static void 1095 in_arpreply(struct mbuf *m, in_addr_t taddr, in_addr_t myaddr) 1096 { 1097 struct ifnet *ifp = m->m_pkthdr.rcvif; 1098 const uint8_t *enaddr; 1099 struct arphdr *ah; 1100 struct sockaddr sa; 1101 struct ether_header *eh; 1102 1103 ah = mtod(m, struct arphdr *); 1104 if (ntohs(ah->ar_op) != ARPOP_REQUEST) { 1105 m_freem(m); 1106 return; 1107 } 1108 1109 enaddr = (const uint8_t *)IF_LLADDR(ifp); 1110 if (taddr == myaddr) { 1111 /* I am the target */ 1112 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 1113 memcpy(ar_sha(ah), enaddr, ah->ar_hln); 1114 } else { 1115 struct llinfo_arp *la; 1116 struct rtentry *rt; 1117 1118 la = arplookup(taddr, FALSE, RTL_DONTREPORT, SIN_PROXY); 1119 if (la == NULL) { 1120 struct sockaddr_in sin; 1121 1122 if (!arp_proxyall) { 1123 m_freem(m); 1124 return; 1125 } 1126 1127 bzero(&sin, sizeof sin); 1128 sin.sin_family = AF_INET; 1129 sin.sin_len = sizeof sin; 1130 sin.sin_addr.s_addr = taddr; 1131 1132 rt = rtpurelookup((struct sockaddr *)&sin); 1133 if (rt == NULL) { 1134 m_freem(m); 1135 return; 1136 } 1137 --rt->rt_refcnt; 1138 /* 1139 * Don't send proxies for nodes on the same interface 1140 * as this one came out of, or we'll get into a fight 1141 * over who claims what Ether address. 1142 */ 1143 if (rt->rt_ifp == ifp) { 1144 m_freem(m); 1145 return; 1146 } 1147 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 1148 memcpy(ar_sha(ah), enaddr, ah->ar_hln); 1149 #ifdef DEBUG_PROXY 1150 kprintf("arp: proxying for %s\n", inet_ntoa(itaddr)); 1151 #endif 1152 } else { 1153 struct sockaddr_dl *sdl; 1154 1155 rt = la->la_rt; 1156 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 1157 sdl = SDL(rt->rt_gateway); 1158 memcpy(ar_sha(ah), LLADDR(sdl), ah->ar_hln); 1159 } 1160 } 1161 1162 memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln); 1163 memcpy(ar_spa(ah), &taddr, ah->ar_pln); 1164 ah->ar_op = htons(ARPOP_REPLY); 1165 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 1166 switch (ifp->if_type) { 1167 case IFT_ETHER: 1168 /* 1169 * May not be correct for types not explictly 1170 * listed, but it is our best guess. 1171 */ 1172 default: 1173 eh = (struct ether_header *)sa.sa_data; 1174 memcpy(eh->ether_dhost, ar_tha(ah), sizeof eh->ether_dhost); 1175 eh->ether_type = htons(ETHERTYPE_ARP); 1176 break; 1177 } 1178 sa.sa_family = AF_UNSPEC; 1179 sa.sa_len = sizeof sa; 1180 ifp->if_output(ifp, m, &sa, NULL); 1181 } 1182 1183 #endif /* INET */ 1184 1185 /* 1186 * Free an arp entry. If the arp entry is actively referenced or represents 1187 * a static entry we only clear it back to an unresolved state, otherwise 1188 * we destroy the entry entirely. 1189 * 1190 * Note that static entries are created when route add ... -interface is used 1191 * to create an interface route to a (direct) destination. 1192 */ 1193 static void 1194 arptfree(struct llinfo_arp *la) 1195 { 1196 struct rtentry *rt = la->la_rt; 1197 struct sockaddr_dl *sdl; 1198 1199 if (rt == NULL) 1200 panic("arptfree"); 1201 sdl = SDL(rt->rt_gateway); 1202 if (sdl != NULL && 1203 ((rt->rt_refcnt > 0 && sdl->sdl_family == AF_LINK) || 1204 (rt->rt_flags & RTF_STATIC))) { 1205 sdl->sdl_alen = 0; 1206 la->la_preempt = la->la_asked = 0; 1207 rt->rt_flags &= ~RTF_REJECT; 1208 return; 1209 } 1210 rtrequest(RTM_DELETE, rt_key(rt), NULL, rt_mask(rt), 0, NULL); 1211 } 1212 1213 /* 1214 * Lookup or enter a new address in arptab. 1215 */ 1216 static struct llinfo_arp * 1217 arplookup(in_addr_t addr, boolean_t create, boolean_t generate_report, 1218 boolean_t proxy) 1219 { 1220 struct rtentry *rt; 1221 struct sockaddr_inarp sin = { sizeof sin, AF_INET }; 1222 const char *why = NULL; 1223 1224 sin.sin_addr.s_addr = addr; 1225 sin.sin_other = proxy ? SIN_PROXY : 0; 1226 if (create) { 1227 rt = _rtlookup((struct sockaddr *)&sin, 1228 generate_report, RTL_DOCLONE); 1229 } else { 1230 rt = rtpurelookup((struct sockaddr *)&sin); 1231 } 1232 if (rt == NULL) 1233 return (NULL); 1234 rt->rt_refcnt--; 1235 1236 if (rt->rt_flags & RTF_GATEWAY) 1237 why = "host is not on local network"; 1238 else if (!(rt->rt_flags & RTF_LLINFO)) 1239 why = "could not allocate llinfo"; 1240 else if (rt->rt_gateway->sa_family != AF_LINK) 1241 why = "gateway route is not ours"; 1242 1243 if (why) { 1244 if (create && log_arp_creation_failure) { 1245 log(LOG_DEBUG, "arplookup %s failed: %s\n", 1246 inet_ntoa(sin.sin_addr), why); 1247 } 1248 if (rt->rt_refcnt <= 0 && (rt->rt_flags & RTF_WASCLONED)) { 1249 /* No references to this route. Purge it. */ 1250 rtrequest(RTM_DELETE, rt_key(rt), rt->rt_gateway, 1251 rt_mask(rt), rt->rt_flags, NULL); 1252 } 1253 return (NULL); 1254 } 1255 return (rt->rt_llinfo); 1256 } 1257 1258 void 1259 arp_ifinit(struct ifnet *ifp, struct ifaddr *ifa) 1260 { 1261 ifa->ifa_rtrequest = arp_rtrequest; 1262 ifa->ifa_flags |= RTF_CLONING; 1263 } 1264 1265 void 1266 arp_gratuitous(struct ifnet *ifp, struct ifaddr *ifa) 1267 { 1268 if (IA_SIN(ifa)->sin_addr.s_addr != INADDR_ANY) { 1269 arprequest_async(ifp, &IA_SIN(ifa)->sin_addr, 1270 &IA_SIN(ifa)->sin_addr, NULL); 1271 } 1272 } 1273 1274 static void 1275 arp_ifaddr(void *arg __unused, struct ifnet *ifp, 1276 enum ifaddr_event event, struct ifaddr *ifa) 1277 { 1278 if (ifa->ifa_rtrequest != arp_rtrequest) /* XXX need a generic way */ 1279 return; 1280 if (ifa->ifa_addr->sa_family != AF_INET) 1281 return; 1282 if (event == IFADDR_EVENT_DELETE) 1283 return; 1284 1285 /* 1286 * - CARP interfaces will take care of gratuitous ARP themselves. 1287 * - If we are the CARP interface's parent, don't send gratuitous 1288 * ARP to avoid unnecessary confusion. 1289 */ 1290 #ifdef CARP 1291 if (ifp->if_type != IFT_CARP && ifp->if_carp == NULL) 1292 #endif 1293 { 1294 arp_gratuitous(ifp, ifa); 1295 } 1296 } 1297 1298 static void 1299 arp_init(void) 1300 { 1301 int cpu; 1302 1303 for (cpu = 0; cpu < ncpus2; cpu++) 1304 LIST_INIT(&llinfo_arp_list[cpu]); 1305 1306 netisr_register(NETISR_ARP, arpintr, NULL); 1307 1308 EVENTHANDLER_REGISTER(ifaddr_event, arp_ifaddr, NULL, 1309 EVENTHANDLER_PRI_LAST); 1310 } 1311 1312 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0); 1313