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 MALLOC_DEFINE(M_ARP, "arp", "ARP"); 110 111 SYSCTL_DECL(_net_link_ether); 112 SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, ""); 113 114 /* timer values */ 115 static int arpt_prune = (5*60*1); /* walk list every 5 minutes */ 116 static int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */ 117 static int arpt_down = 20; /* once declared down, don't send for 20 sec */ 118 119 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, prune_intvl, CTLFLAG_RW, 120 &arpt_prune, 0, ""); 121 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW, 122 &arpt_keep, 0, ""); 123 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, host_down_time, CTLFLAG_RW, 124 &arpt_down, 0, ""); 125 126 #define rt_expire rt_rmx.rmx_expire 127 128 struct llinfo_arp { 129 LIST_ENTRY(llinfo_arp) la_le; 130 struct rtentry *la_rt; 131 struct mbuf *la_hold; /* last packet until resolved/timeout */ 132 u_short la_preempt; /* countdown for pre-expiry arps */ 133 u_short la_asked; /* #times we QUERIED following expiration */ 134 }; 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 static int arp_ignore_probes = 1; 142 143 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW, 144 &arp_maxtries, 0, "ARP resolution attempts before returning error"); 145 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW, 146 &useloopback, 0, "Use the loopback interface for local traffic"); 147 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW, 148 &arp_proxyall, 0, "Enable proxy ARP for all suitable requests"); 149 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, restricted_match, CTLFLAG_RW, 150 &arp_restricted_match, 0, "Only match against the sender"); 151 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, refresh, CTLFLAG_RW, 152 &arp_refresh, 0, "Preemptively refresh the ARP"); 153 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, ignore_probes, CTLFLAG_RW, 154 &arp_ignore_probes, 0, "Ignore ARP probes"); 155 156 static void arp_rtrequest(int, struct rtentry *); 157 static void arprequest(struct ifnet *, const struct in_addr *, 158 const struct in_addr *, const u_char *); 159 static void arprequest_async(struct ifnet *, const struct in_addr *, 160 const struct in_addr *, const u_char *); 161 static void arpintr(netmsg_t msg); 162 static void arptfree(struct llinfo_arp *); 163 static void arptimer(void *); 164 static struct llinfo_arp * 165 arplookup(in_addr_t, boolean_t, boolean_t); 166 #ifdef INET 167 static void in_arpinput(struct mbuf *); 168 static void in_arpreply(struct mbuf *m, in_addr_t, in_addr_t); 169 static void arp_update_msghandler(netmsg_t); 170 static void arp_reply_msghandler(netmsg_t); 171 #endif 172 173 struct arp_pcpu_data { 174 LIST_HEAD(, llinfo_arp) llinfo_list; 175 struct callout timer_ch; 176 struct netmsg_base timer_nmsg; 177 }; 178 179 static struct arp_pcpu_data *arp_data[MAXCPU]; 180 181 /* 182 * Timeout routine. Age arp_tab entries periodically. 183 */ 184 static void 185 arptimer_dispatch(netmsg_t nmsg) 186 { 187 struct arp_pcpu_data *ad = nmsg->lmsg.u.ms_resultp; 188 struct llinfo_arp *la, *nla; 189 190 ASSERT_NETISR_NCPUS(mycpuid); 191 192 /* Reply ASAP */ 193 crit_enter(); 194 netisr_replymsg(&nmsg->base, 0); 195 crit_exit(); 196 197 LIST_FOREACH_MUTABLE(la, &ad->llinfo_list, la_le, nla) { 198 if (la->la_rt->rt_expire && la->la_rt->rt_expire <= time_uptime) 199 arptfree(la); 200 } 201 callout_reset(&ad->timer_ch, arpt_prune * hz, arptimer, &ad->timer_nmsg); 202 } 203 204 static void 205 arptimer(void *xnm) 206 { 207 struct netmsg_base *nm = xnm; 208 209 KKASSERT(mycpuid < netisr_ncpus); 210 211 crit_enter(); 212 if (nm->lmsg.ms_flags & MSGF_DONE) 213 netisr_sendmsg_oncpu(nm); 214 crit_exit(); 215 } 216 217 /* 218 * Parallel to llc_rtrequest. 219 * 220 * Called after a route is successfully added to the tree to fix-up the 221 * route and initiate arp operations if required. 222 */ 223 static void 224 arp_rtrequest(int req, struct rtentry *rt) 225 { 226 struct sockaddr *gate = rt->rt_gateway; 227 struct llinfo_arp *la = rt->rt_llinfo; 228 229 struct sockaddr_dl null_sdl = { sizeof null_sdl, AF_LINK }; 230 231 if (rt->rt_flags & RTF_GATEWAY) 232 return; 233 234 switch (req) { 235 case RTM_ADD: 236 /* 237 * XXX: If this is a manually added route to interface 238 * such as older version of routed or gated might provide, 239 * restore cloning bit. 240 */ 241 if (!(rt->rt_flags & RTF_HOST) && 242 SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff) 243 rt->rt_flags |= RTF_CLONING; 244 if (rt->rt_flags & RTF_CLONING) { 245 /* 246 * Case 1: This route should come from a route to iface. 247 */ 248 rt_setgate(rt, rt_key(rt), 249 (struct sockaddr *)&null_sdl); 250 gate = rt->rt_gateway; 251 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 252 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 253 rt->rt_expire = time_uptime; 254 break; 255 } 256 /* 257 * Announce a new entry if requested, and only announce it 258 * once on cpu0. 259 */ 260 if ((rt->rt_flags & RTF_ANNOUNCE) && mycpuid == 0) { 261 arprequest(rt->rt_ifp, 262 &SIN(rt_key(rt))->sin_addr, 263 &SIN(rt_key(rt))->sin_addr, 264 LLADDR(SDL(gate))); 265 } 266 /*FALLTHROUGH*/ 267 case RTM_RESOLVE: 268 if (gate->sa_family != AF_LINK || 269 gate->sa_len < sizeof(struct sockaddr_dl)) { 270 log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n"); 271 break; 272 } 273 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 274 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 275 if (la != NULL) 276 break; /* This happens on a route change */ 277 /* 278 * Case 2: This route may come from cloning, or a manual route 279 * add with a LL address. 280 */ 281 R_Malloc(la, struct llinfo_arp *, sizeof *la); 282 rt->rt_llinfo = la; 283 if (la == NULL) { 284 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); 285 break; 286 } 287 bzero(la, sizeof *la); 288 la->la_rt = rt; 289 rt->rt_flags |= RTF_LLINFO; 290 LIST_INSERT_HEAD(&arp_data[mycpuid]->llinfo_list, la, la_le); 291 292 #ifdef INET 293 /* 294 * This keeps the multicast addresses from showing up 295 * in `arp -a' listings as unresolved. It's not actually 296 * functional. Then the same for broadcast. 297 */ 298 if (IN_MULTICAST(ntohl(SIN(rt_key(rt))->sin_addr.s_addr))) { 299 ETHER_MAP_IP_MULTICAST(&SIN(rt_key(rt))->sin_addr, 300 LLADDR(SDL(gate))); 301 SDL(gate)->sdl_alen = 6; 302 rt->rt_expire = 0; 303 } 304 if (in_broadcast(SIN(rt_key(rt))->sin_addr, rt->rt_ifp)) { 305 memcpy(LLADDR(SDL(gate)), rt->rt_ifp->if_broadcastaddr, 306 rt->rt_ifp->if_addrlen); 307 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen; 308 rt->rt_expire = 0; 309 } 310 #endif 311 312 /* 313 * This fixes up the routing interface for local addresses. 314 * The route is adjusted to point at lo0 and the expiration 315 * timer is disabled. 316 * 317 * NOTE: This prevents locally targetted traffic from going 318 * out the hardware interface, which is inefficient 319 * and might not work if the hardware cannot listen 320 * to its own transmitted packets. Setting 321 * net.link.ether.inet.useloopback to 0 will force 322 * packets for local addresses out the hardware (and 323 * it is expected to receive its own packet). 324 * 325 * XXX We should just be able to test RTF_LOCAL here instead 326 * of having to compare IPs. 327 */ 328 if (SIN(rt_key(rt))->sin_addr.s_addr == 329 (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) { 330 rt->rt_expire = 0; 331 bcopy(IF_LLADDR(rt->rt_ifp), LLADDR(SDL(gate)), 332 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen); 333 if (useloopback) 334 rt->rt_ifp = loif; 335 } 336 break; 337 338 case RTM_DELETE: 339 if (la == NULL) 340 break; 341 LIST_REMOVE(la, la_le); 342 rt->rt_llinfo = NULL; 343 rt->rt_flags &= ~RTF_LLINFO; 344 if (la->la_hold != NULL) 345 m_freem(la->la_hold); 346 Free(la); 347 break; 348 } 349 } 350 351 static struct mbuf * 352 arpreq_alloc(struct ifnet *ifp, const struct in_addr *sip, 353 const struct in_addr *tip, const u_char *enaddr) 354 { 355 struct mbuf *m; 356 struct arphdr *ah; 357 u_short ar_hrd; 358 359 if ((m = m_gethdr(M_NOWAIT, MT_DATA)) == NULL) 360 return NULL; 361 m->m_pkthdr.rcvif = NULL; 362 363 switch (ifp->if_type) { 364 case IFT_ETHER: 365 /* 366 * This may not be correct for types not explicitly 367 * listed, but this is our best guess 368 */ 369 default: 370 ar_hrd = htons(ARPHRD_ETHER); 371 372 m->m_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 373 m->m_pkthdr.len = m->m_len; 374 MH_ALIGN(m, m->m_len); 375 376 ah = mtod(m, struct arphdr *); 377 break; 378 } 379 380 ah->ar_hrd = ar_hrd; 381 ah->ar_pro = htons(ETHERTYPE_IP); 382 ah->ar_hln = ifp->if_addrlen; /* hardware address length */ 383 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 384 ah->ar_op = htons(ARPOP_REQUEST); 385 memcpy(ar_sha(ah), enaddr, ah->ar_hln); 386 memset(ar_tha(ah), 0, ah->ar_hln); 387 memcpy(ar_spa(ah), sip, ah->ar_pln); 388 memcpy(ar_tpa(ah), tip, ah->ar_pln); 389 390 return m; 391 } 392 393 static void 394 arpreq_send(struct ifnet *ifp, struct mbuf *m) 395 { 396 struct sockaddr sa; 397 struct ether_header *eh; 398 399 ASSERT_NETISR_NCPUS(mycpuid); 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 ASSERT_NETISR_NCPUS(mycpuid); 445 446 if (enaddr == NULL) { 447 if (ifp->if_bridge) { 448 enaddr = IF_LLADDR(ether_bridge_interface(ifp)); 449 } else { 450 enaddr = IF_LLADDR(ifp); 451 } 452 } 453 454 m = arpreq_alloc(ifp, sip, tip, enaddr); 455 if (m == NULL) 456 return; 457 arpreq_send(ifp, m); 458 } 459 460 /* 461 * Same as arprequest(), except: 462 * - Caller is allowed to hold ifp's serializer 463 * - Network output is done in protocol thead 464 */ 465 static void 466 arprequest_async(struct ifnet *ifp, const struct in_addr *sip, 467 const struct in_addr *tip, const u_char *enaddr) 468 { 469 struct mbuf *m; 470 struct netmsg_packet *pmsg; 471 int cpu; 472 473 if (enaddr == NULL) { 474 if (ifp->if_bridge) { 475 enaddr = IF_LLADDR(ether_bridge_interface(ifp)); 476 } else { 477 enaddr = IF_LLADDR(ifp); 478 } 479 } 480 m = arpreq_alloc(ifp, sip, tip, enaddr); 481 if (m == NULL) 482 return; 483 484 pmsg = &m->m_hdr.mh_netmsg; 485 netmsg_init(&pmsg->base, NULL, &netisr_apanic_rport, 486 0, arpreq_send_handler); 487 pmsg->nm_packet = m; 488 pmsg->base.lmsg.u.ms_resultp = ifp; 489 490 if (mycpuid < netisr_ncpus) 491 cpu = mycpuid; 492 else 493 cpu = 0; 494 lwkt_sendmsg(netisr_cpuport(cpu), &pmsg->base.lmsg); 495 } 496 497 /* 498 * Resolve an IP address into an ethernet address. If success, 499 * desten is filled in. If there is no entry in arptab, 500 * set one up and broadcast a request for the IP address. 501 * Hold onto this mbuf and resend it once the address 502 * is finally resolved. A return value of 1 indicates 503 * that desten has been filled in and the packet should be sent 504 * normally; a 0 return indicates that the packet has been 505 * taken over here, either now or for later transmission. 506 */ 507 int 508 arpresolve(struct ifnet *ifp, struct rtentry *rt0, struct mbuf *m, 509 struct sockaddr *dst, u_char *desten) 510 { 511 struct rtentry *rt = NULL; 512 struct llinfo_arp *la = NULL; 513 struct sockaddr_dl *sdl; 514 int error; 515 516 if (m->m_flags & M_BCAST) { /* broadcast */ 517 memcpy(desten, ifp->if_broadcastaddr, ifp->if_addrlen); 518 return 0; 519 } 520 if (m->m_flags & M_MCAST) {/* multicast */ 521 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); 522 return 0; 523 } 524 if (rt0 != NULL) { 525 error = rt_llroute(dst, rt0, &rt); 526 if (error != 0) { 527 m_freem(m); 528 return error; 529 } 530 la = rt->rt_llinfo; 531 } 532 if (la == NULL) { 533 la = arplookup(SIN(dst)->sin_addr.s_addr, TRUE, FALSE); 534 if (la != NULL) 535 rt = la->la_rt; 536 } 537 if (la == NULL || rt == NULL) { 538 char addr[INET_ADDRSTRLEN]; 539 540 log(LOG_DEBUG, "arpresolve: can't allocate llinfo for %s%s%s\n", 541 kinet_ntoa(SIN(dst)->sin_addr, addr), la ? "la" : " ", 542 rt ? "rt" : ""); 543 m_freem(m); 544 return ENOBUFS; 545 } 546 547 /* 548 * Check the address family and length is valid, the address 549 * is resolved; otherwise, try to resolve. 550 */ 551 sdl = SDL(rt->rt_gateway); 552 if ((rt->rt_expire == 0 || rt->rt_expire > time_uptime) && 553 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 554 /* 555 * If entry has an expiry time and it is approaching, 556 * see if we need to send an ARP request within this 557 * arpt_down interval. 558 */ 559 if ((rt->rt_expire != 0) && 560 (time_uptime + la->la_preempt > rt->rt_expire)) { 561 arprequest(ifp, 562 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 563 &SIN(dst)->sin_addr, 564 NULL); 565 la->la_preempt--; 566 } 567 568 bcopy(LLADDR(sdl), desten, sdl->sdl_alen); 569 return 0; 570 } 571 572 /* 573 * If ARP is disabled or static on this interface, stop. 574 * XXX 575 * Probably should not allocate empty llinfo struct if we are 576 * not going to be sending out an arp request. 577 */ 578 if (ifp->if_flags & (IFF_NOARP | IFF_STATICARP)) { 579 m_freem(m); 580 return ifp->if_flags & IFF_NOARP ? ENOTSUP : EINVAL; 581 } 582 583 /* 584 * There is an arptab entry, but no ethernet address 585 * response yet. Replace the held mbuf with this 586 * latest one. 587 */ 588 if (la->la_hold != NULL) 589 m_freem(la->la_hold); 590 la->la_hold = m; 591 592 /* 593 * Return EWOULDBLOCK if we have tried less than arp_maxtries. It 594 * will be masked by ether_output(). Return EHOSTDOWN/EHOSTUNREACH 595 * if we have already sent arp_maxtries ARP requests. Retransmit the 596 * ARP request, but not faster than one request per second. 597 */ 598 if (la->la_asked < arp_maxtries) 599 error = EWOULDBLOCK; 600 else 601 error = (rt != NULL && rt->rt_flags & RTF_GATEWAY) ? 602 EHOSTUNREACH : EHOSTDOWN; 603 604 if (rt->rt_expire || ((rt->rt_flags & RTF_STATIC) && !sdl->sdl_alen)) { 605 rt->rt_flags &= ~RTF_REJECT; 606 if (la->la_asked == 0 || rt->rt_expire != time_uptime) { 607 rt->rt_expire = time_uptime; 608 arprequest(ifp, 609 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 610 &SIN(dst)->sin_addr, 611 NULL); 612 if (la->la_asked++ >= arp_maxtries) { 613 rt->rt_expire += arpt_down; 614 la->la_preempt = arp_maxtries; 615 rt_rtmsg(RTM_MISS, rt, rt->rt_ifp, 0); 616 } 617 } 618 } 619 return error; 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(netmsg_t msg) 628 { 629 struct mbuf *m = msg->packet.nm_packet; 630 struct arphdr *ar; 631 u_short ar_hrd; 632 char hexstr[6]; 633 634 if (m->m_len < sizeof(struct arphdr) && 635 (m = m_pullup(m, sizeof(struct arphdr))) == NULL) { 636 log(LOG_ERR, "arp: runt packet -- m_pullup failed\n"); 637 return; 638 } 639 ar = mtod(m, struct arphdr *); 640 641 ar_hrd = ntohs(ar->ar_hrd); 642 if (ar_hrd != ARPHRD_ETHER && ar_hrd != ARPHRD_IEEE802) { 643 hexncpy((unsigned char *)&ar->ar_hrd, 2, hexstr, 5, NULL); 644 log(LOG_ERR, "arp: unknown hardware address format (0x%s)\n", 645 hexstr); 646 m_freem(m); 647 return; 648 } 649 650 if (m->m_pkthdr.len < arphdr_len(ar)) { 651 if ((m = m_pullup(m, arphdr_len(ar))) == NULL) { 652 log(LOG_ERR, "arp: runt packet\n"); 653 return; 654 } 655 ar = mtod(m, struct arphdr *); 656 } 657 658 switch (ntohs(ar->ar_pro)) { 659 #ifdef INET 660 case ETHERTYPE_IP: 661 in_arpinput(m); 662 return; 663 #endif 664 } 665 m_freem(m); 666 /* msg was embedded in the mbuf, do not reply! */ 667 } 668 669 #ifdef INET 670 /* 671 * ARP for Internet protocols on 10 Mb/s Ethernet. 672 * Algorithm is that given in RFC 826. 673 * In addition, a sanity check is performed on the sender 674 * protocol address, to catch impersonators. 675 * We no longer handle negotiations for use of trailer protocol: 676 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 677 * along with IP replies if we wanted trailers sent to us, 678 * and also sent them in response to IP replies. 679 * This allowed either end to announce the desire to receive 680 * trailer packets. 681 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 682 * but formerly didn't normally send requests. 683 */ 684 685 static int log_arp_wrong_iface = 1; 686 static int log_arp_movements = 1; 687 static int log_arp_permanent_modify = 1; 688 static int log_arp_creation_failure = 1; 689 690 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW, 691 &log_arp_wrong_iface, 0, 692 "Log arp packets arriving on the wrong interface"); 693 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_movements, CTLFLAG_RW, 694 &log_arp_movements, 0, 695 "Log arp replies from MACs different than the one in the cache"); 696 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_permanent_modify, CTLFLAG_RW, 697 &log_arp_permanent_modify, 0, 698 "Log arp replies from MACs different than the one " 699 "in the permanent arp entry"); 700 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_creation_failure, CTLFLAG_RW, 701 &log_arp_creation_failure, 0, "Log arp creation failure"); 702 703 /* 704 * Returns non-zero if the routine updated anything. 705 */ 706 static int 707 arp_update_oncpu(struct mbuf *m, in_addr_t saddr, boolean_t create, 708 boolean_t dologging) 709 { 710 struct arphdr *ah = mtod(m, struct arphdr *); 711 struct ifnet *ifp = m->m_pkthdr.rcvif; 712 struct llinfo_arp *la; 713 struct sockaddr_dl *sdl; 714 struct rtentry *rt; 715 char hexstr[2][64]; 716 char sbuf[INET_ADDRSTRLEN]; 717 int changed = create; 718 719 KASSERT(curthread->td_type == TD_TYPE_NETISR, 720 ("arp update not in netisr")); 721 722 la = arplookup(saddr, create, FALSE); 723 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { 724 struct in_addr isaddr = { saddr }; 725 int rt_cmd = sdl->sdl_alen == 0 ? RTM_ADD : RTM_CHANGE; 726 bool do_rtmsg = false; 727 728 /* 729 * Normally arps coming in on the wrong interface are ignored, 730 * but if we are bridging and the two interfaces belong to 731 * the same bridge, or one is a member of the bridge which 732 * is the other, then it isn't an error. 733 */ 734 if (rt->rt_ifp != ifp) { 735 /* 736 * (1) ifp and rt_ifp both members of same bridge 737 * (2) rt_ifp member of bridge ifp 738 * (3) ifp member of bridge rt_ifp 739 * 740 * Always replace rt_ifp with the bridge ifc. 741 */ 742 struct ifnet *nifp; 743 744 if (ifp->if_bridge && 745 rt->rt_ifp->if_bridge == ifp->if_bridge) { 746 nifp = ether_bridge_interface(ifp); 747 } else if (rt->rt_ifp->if_bridge && 748 ether_bridge_interface(rt->rt_ifp) == ifp) { 749 nifp = ifp; 750 } else if (ifp->if_bridge && 751 ether_bridge_interface(ifp) == rt->rt_ifp) { 752 nifp = rt->rt_ifp; 753 } else { 754 nifp = NULL; 755 } 756 757 if ((log_arp_wrong_iface == 1 && nifp == NULL) || 758 log_arp_wrong_iface == 2) { 759 hexncpy((u_char *)ar_sha(ah), ifp->if_addrlen, 760 hexstr[0], HEX_NCPYLEN(ifp->if_addrlen), ":"); 761 log(LOG_ERR, 762 "arp: %s is on %s " 763 "but got reply from %s on %s\n", 764 kinet_ntoa(isaddr, sbuf), 765 rt->rt_ifp->if_xname, hexstr[0], 766 ifp->if_xname); 767 } 768 if (nifp == NULL) 769 return 0; 770 771 /* 772 * nifp is our man! Replace rt_ifp and adjust 773 * the sdl. 774 */ 775 ifp = rt->rt_ifp = nifp; 776 if (sdl->sdl_type != ifp->if_type) { 777 sdl->sdl_type = ifp->if_type; 778 changed = 1; 779 do_rtmsg = true; 780 } 781 if (sdl->sdl_index != ifp->if_index) { 782 sdl->sdl_index = ifp->if_index; 783 changed = 1; 784 do_rtmsg = true; 785 } 786 } 787 if (sdl->sdl_alen && 788 bcmp(ar_sha(ah), LLADDR(sdl), sdl->sdl_alen)) { 789 changed = 1; 790 if (rt->rt_expire != 0) { 791 if (dologging && log_arp_movements) { 792 hexncpy((u_char *)LLADDR(sdl), ifp->if_addrlen, 793 hexstr[0], HEX_NCPYLEN(ifp->if_addrlen), ":"); 794 hexncpy((u_char *)ar_sha(ah), ifp->if_addrlen, 795 hexstr[1], HEX_NCPYLEN(ifp->if_addrlen), ":"); 796 log(LOG_INFO, 797 "arp: %s moved from %s to %s on %s\n", 798 kinet_ntoa(isaddr, sbuf), hexstr[0], hexstr[1], 799 ifp->if_xname); 800 } 801 } else { 802 if (dologging && log_arp_permanent_modify) { 803 hexncpy((u_char *)ar_sha(ah), ifp->if_addrlen, 804 hexstr[0], HEX_NCPYLEN(ifp->if_addrlen), ":"); 805 log(LOG_ERR, 806 "arp: %s attempts to modify " 807 "permanent entry for %s on %s\n", 808 hexstr[0], kinet_ntoa(isaddr, sbuf), ifp->if_xname); 809 } 810 return changed; 811 } 812 do_rtmsg = true; 813 } 814 /* 815 * sanity check for the address length. 816 * XXX this does not work for protocols with variable address 817 * length. -is 818 */ 819 if (dologging && sdl->sdl_alen && sdl->sdl_alen != ah->ar_hln) { 820 hexncpy((u_char *)ar_sha(ah), ifp->if_addrlen, 821 hexstr[0], HEX_NCPYLEN(ifp->if_addrlen), ":"); 822 log(LOG_WARNING, 823 "arp from %s: new addr len %d, was %d", 824 hexstr[0], ah->ar_hln, sdl->sdl_alen); 825 } 826 if (ifp->if_addrlen != ah->ar_hln) { 827 if (dologging) { 828 hexncpy((u_char *)ar_sha(ah), ifp->if_addrlen, 829 hexstr[0], HEX_NCPYLEN(ifp->if_addrlen), ":"); 830 log(LOG_WARNING, 831 "arp from %s: addr len: new %d, i/f %d " 832 "(ignored)", hexstr[0], 833 ah->ar_hln, ifp->if_addrlen); 834 } 835 return changed; 836 } 837 if (sdl->sdl_alen == 0) 838 do_rtmsg = true; 839 memcpy(LLADDR(sdl), ar_sha(ah), sdl->sdl_alen = ah->ar_hln); 840 if (rt->rt_expire != 0) { 841 if (rt->rt_expire != time_uptime + arpt_keep && 842 rt->rt_expire != time_uptime + arpt_keep - 1) { 843 rt->rt_expire = time_uptime + arpt_keep; 844 changed = 1; 845 } 846 } 847 if (rt->rt_flags & RTF_REJECT) { 848 rt->rt_flags &= ~RTF_REJECT; 849 changed = 1; 850 } 851 if (la->la_asked != 0) { 852 la->la_asked = 0; 853 changed = 1; 854 } 855 if (la->la_preempt != arp_maxtries) { 856 la->la_preempt = arp_maxtries; 857 changed = 1; 858 } 859 860 /* 861 * This particular cpu might have been holding an mbuf 862 * pending ARP resolution. If so, transmit the mbuf now. 863 */ 864 if (la->la_hold != NULL) { 865 struct mbuf *m = la->la_hold; 866 867 la->la_hold = NULL; 868 m_adj(m, sizeof(struct ether_header)); 869 ifp->if_output(ifp, m, rt_key(rt), rt); 870 changed = 1; 871 } 872 873 if (do_rtmsg && mycpuid == 0) 874 rt_rtmsg(rt_cmd, rt, rt->rt_ifp, 0); 875 } 876 return changed; 877 } 878 879 /* 880 * Called from arpintr() - this routine is run from a single cpu. 881 */ 882 static void 883 in_arpinput(struct mbuf *m) 884 { 885 struct arphdr *ah; 886 struct ifnet *ifp = m->m_pkthdr.rcvif; 887 struct ifaddr_container *ifac; 888 struct in_ifaddr_container *iac; 889 struct in_ifaddr *ia = NULL; 890 struct in_addr isaddr, itaddr, myaddr; 891 uint8_t *enaddr = NULL; 892 int req_len; 893 int changed; 894 char hexstr[64], sbuf[INET_ADDRSTRLEN]; 895 896 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 897 if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) { 898 log(LOG_ERR, "in_arp: runt packet -- m_pullup failed\n"); 899 return; 900 } 901 902 ah = mtod(m, struct arphdr *); 903 memcpy(&isaddr, ar_spa(ah), sizeof isaddr); 904 memcpy(&itaddr, ar_tpa(ah), sizeof itaddr); 905 906 /* 907 * Check both target and sender IP addresses: 908 * 909 * If we receive the packet on the interface owning the address, 910 * then accept the address. 911 * 912 * For a bridge, we accept the address if the receive interface and 913 * the interface owning the address are on the same bridge, and 914 * use the bridge MAC as the is-at response. The bridge will be 915 * responsible for handling the packet. 916 * 917 * (0) Check target IP against CARP IPs 918 */ 919 #ifdef CARP 920 LIST_FOREACH(iac, INADDR_HASH(itaddr.s_addr), ia_hash) { 921 int is_match = 0, is_parent = 0; 922 923 ia = iac->ia; 924 925 /* Skip all ia's which don't match */ 926 if (itaddr.s_addr != ia->ia_addr.sin_addr.s_addr) 927 continue; 928 929 if (ia->ia_ifp->if_type != IFT_CARP) 930 continue; 931 932 if (carp_parent(ia->ia_ifp) == ifp) 933 is_parent = 1; 934 if (is_parent || ia->ia_ifp == ifp) 935 is_match = carp_iamatch(ia); 936 937 if (is_match) { 938 if (is_parent) { 939 /* 940 * The parent interface will also receive 941 * the ethernet broadcast packets, e.g. ARP 942 * REQUEST, so if we could find a CARP 943 * interface of the parent that could match 944 * the target IP address, we then drop the 945 * packets, which is delieverd to us through 946 * the parent interface. 947 */ 948 m_freem(m); 949 return; 950 } 951 goto match; 952 } 953 } 954 #endif /* CARP */ 955 956 /* 957 * (1) Check target IP against our local IPs 958 */ 959 LIST_FOREACH(iac, INADDR_HASH(itaddr.s_addr), ia_hash) { 960 ia = iac->ia; 961 962 /* Skip all ia's which don't match */ 963 if (itaddr.s_addr != ia->ia_addr.sin_addr.s_addr) 964 continue; 965 966 #ifdef CARP 967 /* CARP interfaces are checked in (0) */ 968 if (ia->ia_ifp->if_type == IFT_CARP) 969 continue; 970 #endif 971 972 if (ifp->if_bridge && ia->ia_ifp && 973 ifp->if_bridge == ia->ia_ifp->if_bridge) { 974 ifp = ether_bridge_interface(ifp); 975 goto match; 976 } 977 if (ia->ia_ifp && ia->ia_ifp->if_bridge && 978 ether_bridge_interface(ia->ia_ifp) == ifp) { 979 goto match; 980 } 981 if (ifp->if_bridge && ether_bridge_interface(ifp) == 982 ia->ia_ifp) { 983 goto match; 984 } 985 if (ia->ia_ifp == ifp) { 986 goto match; 987 } 988 } 989 990 /* 991 * (2) Check sender IP against our local IPs 992 */ 993 LIST_FOREACH(iac, INADDR_HASH(isaddr.s_addr), ia_hash) { 994 ia = iac->ia; 995 996 /* Skip all ia's which don't match */ 997 if (isaddr.s_addr != ia->ia_addr.sin_addr.s_addr) 998 continue; 999 1000 if (ifp->if_bridge && ia->ia_ifp && 1001 ifp->if_bridge == ia->ia_ifp->if_bridge) { 1002 ifp = ether_bridge_interface(ifp); 1003 goto match; 1004 } 1005 if (ia->ia_ifp && ia->ia_ifp->if_bridge && 1006 ether_bridge_interface(ia->ia_ifp) == ifp) { 1007 goto match; 1008 } 1009 if (ifp->if_bridge && ether_bridge_interface(ifp) == 1010 ia->ia_ifp) { 1011 goto match; 1012 } 1013 1014 if (ia->ia_ifp == ifp) 1015 goto match; 1016 } 1017 1018 /* 1019 * No match, use the first inet address on the receive interface 1020 * as a dummy address for the rest of the function. 1021 */ 1022 TAILQ_FOREACH(ifac, &ifp->if_addrheads[mycpuid], ifa_link) { 1023 struct ifaddr *ifa = ifac->ifa; 1024 1025 if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_INET) { 1026 ia = ifatoia(ifa); 1027 goto match; 1028 } 1029 } 1030 1031 /* 1032 * If we got here, we didn't find any suitable interface, 1033 * so drop the packet. 1034 */ 1035 m_freem(m); 1036 return; 1037 1038 match: 1039 if (!enaddr) 1040 enaddr = (uint8_t *)IF_LLADDR(ifp); 1041 myaddr = ia->ia_addr.sin_addr; 1042 if (!bcmp(ar_sha(ah), enaddr, ifp->if_addrlen)) { 1043 m_freem(m); /* it's from me, ignore it. */ 1044 return; 1045 } 1046 if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) { 1047 log(LOG_ERR, 1048 "arp: link address is broadcast for IP address %s!\n", 1049 kinet_ntoa(isaddr, sbuf)); 1050 m_freem(m); 1051 return; 1052 } 1053 if (isaddr.s_addr == myaddr.s_addr && myaddr.s_addr != 0) { 1054 hexncpy((u_char *)ar_sha(ah), ifp->if_addrlen, 1055 hexstr, HEX_NCPYLEN(ifp->if_addrlen), ":"); 1056 log(LOG_ERR, 1057 "arp: %s is using my IP address %s!\n", 1058 hexstr, kinet_ntoa(isaddr, sbuf)); 1059 itaddr = myaddr; 1060 goto reply; 1061 } 1062 if (ifp->if_flags & IFF_STATICARP) 1063 goto reply; 1064 1065 /* 1066 * When arp_restricted_match is true and the ARP response is not 1067 * specifically targetted to me, ignore it. Otherwise the entry 1068 * timeout may be updated for an old MAC. 1069 */ 1070 if (arp_restricted_match && itaddr.s_addr != myaddr.s_addr) { 1071 m_freem(m); 1072 return; 1073 } 1074 1075 /* 1076 * Update all CPU's routing tables with this ARP packet. 1077 * 1078 * However, we only need to generate rtmsg on CPU0. 1079 */ 1080 ASSERT_NETISR0; 1081 changed = arp_update_oncpu(m, isaddr.s_addr, 1082 itaddr.s_addr == myaddr.s_addr, 1083 TRUE); 1084 1085 if (netisr_ncpus > 1 && changed) { 1086 struct netmsg_inarp *msg = &m->m_hdr.mh_arpmsg; 1087 1088 netmsg_init(&msg->base, NULL, &netisr_apanic_rport, 1089 0, arp_update_msghandler); 1090 msg->m = m; 1091 msg->saddr = isaddr.s_addr; 1092 msg->taddr = itaddr.s_addr; 1093 msg->myaddr = myaddr.s_addr; 1094 lwkt_sendmsg(netisr_cpuport(1), &msg->base.lmsg); 1095 } else { 1096 goto reply; 1097 } 1098 1099 /* 1100 * Just return here; after all CPUs's routing tables are 1101 * properly updated by this ARP packet, an ARP reply will 1102 * be generated if appropriate. 1103 */ 1104 return; 1105 reply: 1106 in_arpreply(m, itaddr.s_addr, myaddr.s_addr); 1107 } 1108 1109 static void 1110 arp_reply_msghandler(netmsg_t msg) 1111 { 1112 struct netmsg_inarp *rmsg = (struct netmsg_inarp *)msg; 1113 1114 in_arpreply(rmsg->m, rmsg->taddr, rmsg->myaddr); 1115 /* Don't reply this netmsg; netmsg_inarp is embedded in mbuf */ 1116 } 1117 1118 static void 1119 arp_update_msghandler(netmsg_t msg) 1120 { 1121 struct netmsg_inarp *rmsg = (struct netmsg_inarp *)msg; 1122 int nextcpu; 1123 1124 ASSERT_NETISR_NCPUS(mycpuid); 1125 1126 /* 1127 * This message handler will be called on all of the APs; 1128 * no need to generate rtmsg on them. 1129 */ 1130 KASSERT(mycpuid > 0, ("arp update msg on cpu%d", mycpuid)); 1131 arp_update_oncpu(rmsg->m, rmsg->saddr, 1132 rmsg->taddr == rmsg->myaddr, 1133 FALSE); 1134 1135 nextcpu = mycpuid + 1; 1136 if (nextcpu < netisr_ncpus) { 1137 lwkt_forwardmsg(netisr_cpuport(nextcpu), &rmsg->base.lmsg); 1138 } else { 1139 struct mbuf *m = rmsg->m; 1140 in_addr_t saddr = rmsg->saddr; 1141 in_addr_t taddr = rmsg->taddr; 1142 in_addr_t myaddr = rmsg->myaddr; 1143 1144 /* 1145 * Dispatch this mbuf to netisr0 to perform ARP reply, 1146 * if appropriate. 1147 * NOTE: netmsg_inarp is embedded in this mbuf. 1148 */ 1149 netmsg_init(&rmsg->base, NULL, &netisr_apanic_rport, 1150 0, arp_reply_msghandler); 1151 rmsg->m = m; 1152 rmsg->saddr = saddr; 1153 rmsg->taddr = taddr; 1154 rmsg->myaddr = myaddr; 1155 lwkt_sendmsg(netisr_cpuport(0), &rmsg->base.lmsg); 1156 } 1157 } 1158 1159 /* 1160 * Reply to an arp request 1161 */ 1162 static void 1163 in_arpreply(struct mbuf *m, in_addr_t taddr, in_addr_t myaddr) 1164 { 1165 struct ifnet *ifp = m->m_pkthdr.rcvif; 1166 const uint8_t *enaddr; 1167 struct arphdr *ah; 1168 struct sockaddr sa; 1169 struct ether_header *eh; 1170 1171 ASSERT_NETISR0; 1172 1173 ah = mtod(m, struct arphdr *); 1174 if (ntohs(ah->ar_op) != ARPOP_REQUEST) { 1175 m_freem(m); 1176 return; 1177 } 1178 1179 enaddr = (const uint8_t *)IF_LLADDR(ifp); 1180 if (taddr == myaddr) { 1181 /* I am the target */ 1182 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 1183 memcpy(ar_sha(ah), enaddr, ah->ar_hln); 1184 } else { 1185 struct llinfo_arp *la; 1186 struct rtentry *rt; 1187 1188 la = arplookup(taddr, FALSE, SIN_PROXY); 1189 if (la == NULL) { 1190 struct sockaddr_in sin; 1191 #ifdef DEBUG_PROXY 1192 char tbuf[INET_ADDRSTRLEN]; 1193 #endif 1194 1195 if (!arp_proxyall) { 1196 m_freem(m); 1197 return; 1198 } 1199 1200 bzero(&sin, sizeof sin); 1201 sin.sin_family = AF_INET; 1202 sin.sin_len = sizeof sin; 1203 sin.sin_addr.s_addr = taddr; 1204 1205 rt = rtpurelookup((struct sockaddr *)&sin); 1206 if (rt == NULL) { 1207 m_freem(m); 1208 return; 1209 } 1210 --rt->rt_refcnt; 1211 1212 /* 1213 * Don't send proxies for nodes on the same interface 1214 * as this one came out of, or we'll get into a fight 1215 * over who claims what Ether address. 1216 * 1217 * If the rt entry is associated with a bridge, we 1218 * count it as the 'same' interface if ifp is 1219 * associated with the bridge. 1220 */ 1221 if (rt->rt_ifp == ifp || rt->rt_ifp == ifp->if_bridge) { 1222 m_freem(m); 1223 return; 1224 } 1225 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 1226 memcpy(ar_sha(ah), enaddr, ah->ar_hln); 1227 #ifdef DEBUG_PROXY 1228 kprintf("arp: proxying for %s\n", 1229 kinet_ntoa(itaddr, tbuf)); 1230 #endif 1231 } else { 1232 struct sockaddr_dl *sdl; 1233 1234 rt = la->la_rt; 1235 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 1236 sdl = SDL(rt->rt_gateway); 1237 memcpy(ar_sha(ah), LLADDR(sdl), ah->ar_hln); 1238 } 1239 } 1240 1241 memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln); 1242 memcpy(ar_spa(ah), &taddr, ah->ar_pln); 1243 ah->ar_op = htons(ARPOP_REPLY); 1244 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 1245 switch (ifp->if_type) { 1246 case IFT_ETHER: 1247 /* 1248 * May not be correct for types not explictly 1249 * listed, but it is our best guess. 1250 */ 1251 default: 1252 eh = (struct ether_header *)sa.sa_data; 1253 memcpy(eh->ether_dhost, ar_tha(ah), sizeof eh->ether_dhost); 1254 eh->ether_type = htons(ETHERTYPE_ARP); 1255 break; 1256 } 1257 sa.sa_family = AF_UNSPEC; 1258 sa.sa_len = sizeof sa; 1259 ifp->if_output(ifp, m, &sa, NULL); 1260 } 1261 1262 #endif /* INET */ 1263 1264 /* 1265 * Free an arp entry. If the arp entry is actively referenced or represents 1266 * a static entry we only clear it back to an unresolved state, otherwise 1267 * we destroy the entry entirely. 1268 * 1269 * Note that static entries are created when route add ... -interface is used 1270 * to create an interface route to a (direct) destination. 1271 */ 1272 static void 1273 arptfree(struct llinfo_arp *la) 1274 { 1275 struct rtentry *rt = la->la_rt, *nrt; 1276 struct sockaddr_dl *sdl; 1277 int error; 1278 1279 if (rt == NULL) 1280 panic("arptfree"); 1281 sdl = SDL(rt->rt_gateway); 1282 if (sdl != NULL && 1283 ((rt->rt_refcnt > 0 && sdl->sdl_family == AF_LINK) || 1284 (rt->rt_flags & RTF_STATIC))) { 1285 sdl->sdl_alen = 0; 1286 la->la_preempt = la->la_asked = 0; 1287 rt->rt_flags &= ~RTF_REJECT; 1288 return; 1289 } 1290 error = rtrequest(RTM_DELETE, rt_key(rt), NULL, rt_mask(rt), 0, &nrt); 1291 if (error == 0 && nrt != NULL) { 1292 rt_rtmsg(RTM_DELETE, nrt, nrt->rt_ifp, 0); 1293 rtfree(nrt); 1294 } 1295 } 1296 1297 /* 1298 * Lookup or enter a new address in arptab. 1299 */ 1300 static struct llinfo_arp * 1301 arplookup(in_addr_t addr, boolean_t create, 1302 boolean_t proxy) 1303 { 1304 struct rtentry *rt; 1305 struct sockaddr_inarp sin = { sizeof sin, AF_INET }; 1306 const char *why = NULL; 1307 1308 /* Check ARP probes, e.g. from Cisco switches. */ 1309 if (addr == INADDR_ANY && arp_ignore_probes) 1310 return (NULL); 1311 1312 sin.sin_addr.s_addr = addr; 1313 sin.sin_other = proxy ? SIN_PROXY : 0; 1314 if (create) { 1315 rt = rtlookup((struct sockaddr *)&sin); 1316 } else { 1317 rt = rtpurelookup((struct sockaddr *)&sin); 1318 } 1319 if (rt == NULL) 1320 return (NULL); 1321 rt->rt_refcnt--; 1322 1323 if (rt->rt_flags & RTF_GATEWAY) 1324 why = "host is not on local network"; 1325 else if (!(rt->rt_flags & RTF_LLINFO)) 1326 why = "could not allocate llinfo"; 1327 else if (rt->rt_gateway->sa_family != AF_LINK) 1328 why = "gateway route is not ours"; 1329 1330 if (why) { 1331 if (create && log_arp_creation_failure) { 1332 char abuf[INET_ADDRSTRLEN]; 1333 1334 log(LOG_DEBUG, "arplookup %s failed: %s\n", 1335 kinet_ntoa(sin.sin_addr, abuf), why); 1336 } 1337 if (rt->rt_refcnt <= 0 && (rt->rt_flags & RTF_WASCLONED)) { 1338 /* No references to this route. Purge it. */ 1339 rtrequest(RTM_DELETE, rt_key(rt), rt->rt_gateway, 1340 rt_mask(rt), rt->rt_flags, NULL); 1341 } 1342 return (NULL); 1343 } 1344 return (rt->rt_llinfo); 1345 } 1346 1347 void 1348 arp_ifinit(struct ifnet *ifp, struct ifaddr *ifa) 1349 { 1350 ifa->ifa_rtrequest = arp_rtrequest; 1351 ifa->ifa_flags |= RTF_CLONING; 1352 } 1353 1354 void 1355 arp_gratuitous(struct ifnet *ifp, struct ifaddr *ifa) 1356 { 1357 if (IA_SIN(ifa)->sin_addr.s_addr != INADDR_ANY) { 1358 if (IN_NETISR_NCPUS(mycpuid)) { 1359 arprequest(ifp, &IA_SIN(ifa)->sin_addr, 1360 &IA_SIN(ifa)->sin_addr, NULL); 1361 } else { 1362 arprequest_async(ifp, &IA_SIN(ifa)->sin_addr, 1363 &IA_SIN(ifa)->sin_addr, NULL); 1364 } 1365 } 1366 } 1367 1368 static void 1369 arp_ifaddr(void *arg __unused, struct ifnet *ifp, 1370 enum ifaddr_event event, struct ifaddr *ifa) 1371 { 1372 if (ifa->ifa_rtrequest != arp_rtrequest) /* XXX need a generic way */ 1373 return; 1374 if (ifa->ifa_addr->sa_family != AF_INET) 1375 return; 1376 if (event == IFADDR_EVENT_DELETE) 1377 return; 1378 1379 /* 1380 * - CARP interfaces will take care of gratuitous ARP themselves. 1381 * - If we are the CARP interface's parent, don't send gratuitous 1382 * ARP to avoid unnecessary confusion. 1383 */ 1384 #ifdef CARP 1385 if (ifp->if_type != IFT_CARP && ifp->if_carp == NULL) 1386 #endif 1387 { 1388 arp_gratuitous(ifp, ifa); 1389 } 1390 } 1391 1392 static void 1393 arp_init_dispatch(netmsg_t nm) 1394 { 1395 struct arp_pcpu_data *ad; 1396 1397 ASSERT_NETISR_NCPUS(mycpuid); 1398 1399 ad = kmalloc(sizeof(*ad), M_ARP, M_WAITOK | M_ZERO); 1400 1401 LIST_INIT(&ad->llinfo_list); 1402 callout_init_mp(&ad->timer_ch); 1403 netmsg_init(&ad->timer_nmsg, NULL, &netisr_adone_rport, 1404 MSGF_PRIORITY, arptimer_dispatch); 1405 ad->timer_nmsg.lmsg.u.ms_resultp = ad; 1406 1407 arp_data[mycpuid] = ad; 1408 1409 callout_reset(&ad->timer_ch, hz, arptimer, &ad->timer_nmsg); 1410 1411 netisr_forwardmsg(&nm->base, mycpuid + 1); 1412 } 1413 1414 static void 1415 arp_init(void) 1416 { 1417 struct netmsg_base nm; 1418 1419 netmsg_init(&nm, NULL, &curthread->td_msgport, 0, arp_init_dispatch); 1420 netisr_domsg_global(&nm); 1421 1422 netisr_register(NETISR_ARP, arpintr, NULL); 1423 1424 EVENTHANDLER_REGISTER(ifaddr_event, arp_ifaddr, NULL, 1425 EVENTHANDLER_PRI_LAST); 1426 } 1427 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0); 1428