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, 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 RTL_DONTREPORT); 251 gate = rt->rt_gateway; 252 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 253 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 254 rt->rt_expire = time_uptime; 255 break; 256 } 257 /* 258 * Announce a new entry if requested, and only announce it 259 * once on cpu0. 260 */ 261 if ((rt->rt_flags & RTF_ANNOUNCE) && mycpuid == 0) { 262 arprequest(rt->rt_ifp, 263 &SIN(rt_key(rt))->sin_addr, 264 &SIN(rt_key(rt))->sin_addr, 265 LLADDR(SDL(gate))); 266 } 267 /*FALLTHROUGH*/ 268 case RTM_RESOLVE: 269 if (gate->sa_family != AF_LINK || 270 gate->sa_len < sizeof(struct sockaddr_dl)) { 271 log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n"); 272 break; 273 } 274 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 275 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 276 if (la != NULL) 277 break; /* This happens on a route change */ 278 /* 279 * Case 2: This route may come from cloning, or a manual route 280 * add with a LL address. 281 */ 282 R_Malloc(la, struct llinfo_arp *, sizeof *la); 283 rt->rt_llinfo = la; 284 if (la == NULL) { 285 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); 286 break; 287 } 288 bzero(la, sizeof *la); 289 la->la_rt = rt; 290 rt->rt_flags |= RTF_LLINFO; 291 LIST_INSERT_HEAD(&arp_data[mycpuid]->llinfo_list, la, la_le); 292 293 #ifdef INET 294 /* 295 * This keeps the multicast addresses from showing up 296 * in `arp -a' listings as unresolved. It's not actually 297 * functional. Then the same for broadcast. 298 */ 299 if (IN_MULTICAST(ntohl(SIN(rt_key(rt))->sin_addr.s_addr))) { 300 ETHER_MAP_IP_MULTICAST(&SIN(rt_key(rt))->sin_addr, 301 LLADDR(SDL(gate))); 302 SDL(gate)->sdl_alen = 6; 303 rt->rt_expire = 0; 304 } 305 if (in_broadcast(SIN(rt_key(rt))->sin_addr, rt->rt_ifp)) { 306 memcpy(LLADDR(SDL(gate)), rt->rt_ifp->if_broadcastaddr, 307 rt->rt_ifp->if_addrlen); 308 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen; 309 rt->rt_expire = 0; 310 } 311 #endif 312 313 /* 314 * This fixes up the routing interface for local addresses. 315 * The route is adjusted to point at lo0 and the expiration 316 * timer is disabled. 317 * 318 * NOTE: This prevents locally targetted traffic from going 319 * out the hardware interface, which is inefficient 320 * and might not work if the hardware cannot listen 321 * to its own transmitted packets. Setting 322 * net.link.ether.inet.useloopback to 0 will force 323 * packets for local addresses out the hardware (and 324 * it is expected to receive its own packet). 325 * 326 * XXX We should just be able to test RTF_LOCAL here instead 327 * of having to compare IPs. 328 */ 329 if (SIN(rt_key(rt))->sin_addr.s_addr == 330 (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) { 331 rt->rt_expire = 0; 332 bcopy(IF_LLADDR(rt->rt_ifp), LLADDR(SDL(gate)), 333 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen); 334 if (useloopback) 335 rt->rt_ifp = loif; 336 } 337 break; 338 339 case RTM_DELETE: 340 if (la == NULL) 341 break; 342 LIST_REMOVE(la, la_le); 343 rt->rt_llinfo = NULL; 344 rt->rt_flags &= ~RTF_LLINFO; 345 if (la->la_hold != NULL) 346 m_freem(la->la_hold); 347 Free(la); 348 break; 349 } 350 } 351 352 static struct mbuf * 353 arpreq_alloc(struct ifnet *ifp, const struct in_addr *sip, 354 const struct in_addr *tip, const u_char *enaddr) 355 { 356 struct mbuf *m; 357 struct arphdr *ah; 358 u_short ar_hrd; 359 360 if ((m = m_gethdr(M_NOWAIT, MT_DATA)) == NULL) 361 return NULL; 362 m->m_pkthdr.rcvif = NULL; 363 364 switch (ifp->if_type) { 365 case IFT_ETHER: 366 /* 367 * This may not be correct for types not explicitly 368 * listed, but this is our best guess 369 */ 370 default: 371 ar_hrd = htons(ARPHRD_ETHER); 372 373 m->m_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 374 m->m_pkthdr.len = m->m_len; 375 MH_ALIGN(m, m->m_len); 376 377 ah = mtod(m, struct arphdr *); 378 break; 379 } 380 381 ah->ar_hrd = ar_hrd; 382 ah->ar_pro = htons(ETHERTYPE_IP); 383 ah->ar_hln = ifp->if_addrlen; /* hardware address length */ 384 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 385 ah->ar_op = htons(ARPOP_REQUEST); 386 memcpy(ar_sha(ah), enaddr, ah->ar_hln); 387 memset(ar_tha(ah), 0, ah->ar_hln); 388 memcpy(ar_spa(ah), sip, ah->ar_pln); 389 memcpy(ar_tpa(ah), tip, ah->ar_pln); 390 391 return m; 392 } 393 394 static void 395 arpreq_send(struct ifnet *ifp, struct mbuf *m) 396 { 397 struct sockaddr sa; 398 struct ether_header *eh; 399 400 ASSERT_NETISR_NCPUS(mycpuid); 401 402 switch (ifp->if_type) { 403 case IFT_ETHER: 404 /* 405 * This may not be correct for types not explicitly 406 * listed, but this is our best guess 407 */ 408 default: 409 eh = (struct ether_header *)sa.sa_data; 410 /* if_output() will not swap */ 411 eh->ether_type = htons(ETHERTYPE_ARP); 412 memcpy(eh->ether_dhost, ifp->if_broadcastaddr, ifp->if_addrlen); 413 break; 414 } 415 416 sa.sa_family = AF_UNSPEC; 417 sa.sa_len = sizeof(sa); 418 ifp->if_output(ifp, m, &sa, NULL); 419 } 420 421 static void 422 arpreq_send_handler(netmsg_t msg) 423 { 424 struct mbuf *m = msg->packet.nm_packet; 425 struct ifnet *ifp = msg->lmsg.u.ms_resultp; 426 427 arpreq_send(ifp, m); 428 /* nmsg was embedded in the mbuf, do not reply! */ 429 } 430 431 /* 432 * Broadcast an ARP request. Caller specifies: 433 * - arp header source ip address 434 * - arp header target ip address 435 * - arp header source ethernet address 436 * 437 * NOTE: Caller MUST NOT hold ifp's serializer 438 */ 439 static void 440 arprequest(struct ifnet *ifp, const struct in_addr *sip, 441 const struct in_addr *tip, const u_char *enaddr) 442 { 443 struct mbuf *m; 444 445 ASSERT_NETISR_NCPUS(mycpuid); 446 447 if (enaddr == NULL) { 448 if (ifp->if_bridge) { 449 enaddr = IF_LLADDR(ether_bridge_interface(ifp)); 450 } else { 451 enaddr = IF_LLADDR(ifp); 452 } 453 } 454 455 m = arpreq_alloc(ifp, sip, tip, enaddr); 456 if (m == NULL) 457 return; 458 arpreq_send(ifp, m); 459 } 460 461 /* 462 * Same as arprequest(), except: 463 * - Caller is allowed to hold ifp's serializer 464 * - Network output is done in protocol thead 465 */ 466 static void 467 arprequest_async(struct ifnet *ifp, const struct in_addr *sip, 468 const struct in_addr *tip, const u_char *enaddr) 469 { 470 struct mbuf *m; 471 struct netmsg_packet *pmsg; 472 int cpu; 473 474 if (enaddr == NULL) { 475 if (ifp->if_bridge) { 476 enaddr = IF_LLADDR(ether_bridge_interface(ifp)); 477 } else { 478 enaddr = IF_LLADDR(ifp); 479 } 480 } 481 m = arpreq_alloc(ifp, sip, tip, enaddr); 482 if (m == NULL) 483 return; 484 485 pmsg = &m->m_hdr.mh_netmsg; 486 netmsg_init(&pmsg->base, NULL, &netisr_apanic_rport, 487 0, arpreq_send_handler); 488 pmsg->nm_packet = m; 489 pmsg->base.lmsg.u.ms_resultp = ifp; 490 491 if (mycpuid < netisr_ncpus) 492 cpu = mycpuid; 493 else 494 cpu = 0; 495 lwkt_sendmsg(netisr_cpuport(cpu), &pmsg->base.lmsg); 496 } 497 498 /* 499 * Resolve an IP address into an ethernet address. If success, 500 * desten is filled in. If there is no entry in arptab, 501 * set one up and broadcast a request for the IP address. 502 * Hold onto this mbuf and resend it once the address 503 * is finally resolved. A return value of 1 indicates 504 * that desten has been filled in and the packet should be sent 505 * normally; a 0 return indicates that the packet has been 506 * taken over here, either now or for later transmission. 507 */ 508 int 509 arpresolve(struct ifnet *ifp, struct rtentry *rt0, struct mbuf *m, 510 struct sockaddr *dst, u_char *desten) 511 { 512 struct rtentry *rt = NULL; 513 struct llinfo_arp *la = NULL; 514 struct sockaddr_dl *sdl; 515 516 if (m->m_flags & M_BCAST) { /* broadcast */ 517 memcpy(desten, ifp->if_broadcastaddr, ifp->if_addrlen); 518 return (1); 519 } 520 if (m->m_flags & M_MCAST) {/* multicast */ 521 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); 522 return (1); 523 } 524 if (rt0 != NULL) { 525 if (rt_llroute(dst, rt0, &rt) != 0) { 526 m_freem(m); 527 return 0; 528 } 529 la = rt->rt_llinfo; 530 } 531 if (la == NULL) { 532 la = arplookup(SIN(dst)->sin_addr.s_addr, 533 TRUE, RTL_REPORTMSG, 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 (0); 545 } 546 sdl = SDL(rt->rt_gateway); 547 /* 548 * Check the address family and length is valid, the address 549 * is resolved; otherwise, try to resolve. 550 */ 551 if ((rt->rt_expire == 0 || rt->rt_expire > time_uptime) && 552 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 553 /* 554 * If entry has an expiry time and it is approaching, 555 * see if we need to send an ARP request within this 556 * arpt_down interval. 557 */ 558 if ((rt->rt_expire != 0) && 559 (time_uptime + la->la_preempt > rt->rt_expire)) { 560 arprequest(ifp, 561 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 562 &SIN(dst)->sin_addr, 563 NULL); 564 la->la_preempt--; 565 } 566 567 bcopy(LLADDR(sdl), desten, sdl->sdl_alen); 568 return 1; 569 } 570 /* 571 * If ARP is disabled or static on this interface, stop. 572 * XXX 573 * Probably should not allocate empty llinfo struct if we are 574 * not going to be sending out an arp request. 575 */ 576 if (ifp->if_flags & (IFF_NOARP | IFF_STATICARP)) { 577 m_freem(m); 578 return (0); 579 } 580 /* 581 * There is an arptab entry, but no ethernet address 582 * response yet. Replace the held mbuf with this 583 * latest one. 584 */ 585 if (la->la_hold != NULL) 586 m_freem(la->la_hold); 587 la->la_hold = m; 588 if (rt->rt_expire || ((rt->rt_flags & RTF_STATIC) && !sdl->sdl_alen)) { 589 rt->rt_flags &= ~RTF_REJECT; 590 if (la->la_asked == 0 || rt->rt_expire != time_uptime) { 591 rt->rt_expire = time_uptime; 592 if (la->la_asked++ < arp_maxtries) { 593 arprequest(ifp, 594 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 595 &SIN(dst)->sin_addr, 596 NULL); 597 } else { 598 rt->rt_flags |= RTF_REJECT; 599 rt->rt_expire += arpt_down; 600 la->la_asked = 0; 601 la->la_preempt = arp_maxtries; 602 } 603 } 604 } 605 return (0); 606 } 607 608 /* 609 * Common length and type checks are done here, 610 * then the protocol-specific routine is called. 611 */ 612 static void 613 arpintr(netmsg_t msg) 614 { 615 struct mbuf *m = msg->packet.nm_packet; 616 struct arphdr *ar; 617 u_short ar_hrd; 618 char hexstr[6]; 619 620 if (m->m_len < sizeof(struct arphdr) && 621 (m = m_pullup(m, sizeof(struct arphdr))) == NULL) { 622 log(LOG_ERR, "arp: runt packet -- m_pullup failed\n"); 623 return; 624 } 625 ar = mtod(m, struct arphdr *); 626 627 ar_hrd = ntohs(ar->ar_hrd); 628 if (ar_hrd != ARPHRD_ETHER && ar_hrd != ARPHRD_IEEE802) { 629 hexncpy((unsigned char *)&ar->ar_hrd, 2, hexstr, 5, NULL); 630 log(LOG_ERR, "arp: unknown hardware address format (0x%s)\n", 631 hexstr); 632 m_freem(m); 633 return; 634 } 635 636 if (m->m_pkthdr.len < arphdr_len(ar)) { 637 if ((m = m_pullup(m, arphdr_len(ar))) == NULL) { 638 log(LOG_ERR, "arp: runt packet\n"); 639 return; 640 } 641 ar = mtod(m, struct arphdr *); 642 } 643 644 switch (ntohs(ar->ar_pro)) { 645 #ifdef INET 646 case ETHERTYPE_IP: 647 in_arpinput(m); 648 return; 649 #endif 650 } 651 m_freem(m); 652 /* msg was embedded in the mbuf, do not reply! */ 653 } 654 655 #ifdef INET 656 /* 657 * ARP for Internet protocols on 10 Mb/s Ethernet. 658 * Algorithm is that given in RFC 826. 659 * In addition, a sanity check is performed on the sender 660 * protocol address, to catch impersonators. 661 * We no longer handle negotiations for use of trailer protocol: 662 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 663 * along with IP replies if we wanted trailers sent to us, 664 * and also sent them in response to IP replies. 665 * This allowed either end to announce the desire to receive 666 * trailer packets. 667 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 668 * but formerly didn't normally send requests. 669 */ 670 671 static int log_arp_wrong_iface = 1; 672 static int log_arp_movements = 1; 673 static int log_arp_permanent_modify = 1; 674 static int log_arp_creation_failure = 1; 675 676 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW, 677 &log_arp_wrong_iface, 0, 678 "Log arp packets arriving on the wrong interface"); 679 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_movements, CTLFLAG_RW, 680 &log_arp_movements, 0, 681 "Log arp replies from MACs different than the one in the cache"); 682 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_permanent_modify, CTLFLAG_RW, 683 &log_arp_permanent_modify, 0, 684 "Log arp replies from MACs different than the one " 685 "in the permanent arp entry"); 686 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_creation_failure, CTLFLAG_RW, 687 &log_arp_creation_failure, 0, "Log arp creation failure"); 688 689 /* 690 * Returns non-zero if the routine updated anything. 691 */ 692 static int 693 arp_update_oncpu(struct mbuf *m, in_addr_t saddr, boolean_t create, 694 boolean_t generate_report, boolean_t dologging) 695 { 696 struct arphdr *ah = mtod(m, struct arphdr *); 697 struct ifnet *ifp = m->m_pkthdr.rcvif; 698 struct llinfo_arp *la; 699 struct sockaddr_dl *sdl; 700 struct rtentry *rt; 701 char hexstr[2][64]; 702 char sbuf[INET_ADDRSTRLEN]; 703 int changed = create; 704 705 KASSERT(curthread->td_type == TD_TYPE_NETISR, 706 ("arp update not in netisr")); 707 708 la = arplookup(saddr, create, generate_report, FALSE); 709 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { 710 struct in_addr isaddr = { saddr }; 711 712 /* 713 * Normally arps coming in on the wrong interface are ignored, 714 * but if we are bridging and the two interfaces belong to 715 * the same bridge, or one is a member of the bridge which 716 * is the other, then it isn't an error. 717 */ 718 if (rt->rt_ifp != ifp) { 719 /* 720 * (1) ifp and rt_ifp both members of same bridge 721 * (2) rt_ifp member of bridge ifp 722 * (3) ifp member of bridge rt_ifp 723 * 724 * Always replace rt_ifp with the bridge ifc. 725 */ 726 struct ifnet *nifp; 727 728 if (ifp->if_bridge && 729 rt->rt_ifp->if_bridge == ifp->if_bridge) { 730 nifp = ether_bridge_interface(ifp); 731 } else if (rt->rt_ifp->if_bridge && 732 ether_bridge_interface(rt->rt_ifp) == ifp) { 733 nifp = ifp; 734 } else if (ifp->if_bridge && 735 ether_bridge_interface(ifp) == rt->rt_ifp) { 736 nifp = rt->rt_ifp; 737 } else { 738 nifp = NULL; 739 } 740 741 if ((log_arp_wrong_iface == 1 && nifp == NULL) || 742 log_arp_wrong_iface == 2) { 743 hexncpy((u_char *)ar_sha(ah), ifp->if_addrlen, 744 hexstr[0], HEX_NCPYLEN(ifp->if_addrlen), ":"); 745 log(LOG_ERR, 746 "arp: %s is on %s " 747 "but got reply from %s on %s\n", 748 kinet_ntoa(isaddr, sbuf), 749 rt->rt_ifp->if_xname, hexstr[0], 750 ifp->if_xname); 751 } 752 if (nifp == NULL) 753 return 0; 754 755 /* 756 * nifp is our man! Replace rt_ifp and adjust 757 * the sdl. 758 */ 759 ifp = rt->rt_ifp = nifp; 760 if (sdl->sdl_type != ifp->if_type) { 761 sdl->sdl_type = ifp->if_type; 762 changed = 1; 763 } 764 if (sdl->sdl_index != ifp->if_index) { 765 sdl->sdl_index = ifp->if_index; 766 changed = 1; 767 } 768 } 769 if (sdl->sdl_alen && 770 bcmp(ar_sha(ah), LLADDR(sdl), sdl->sdl_alen)) { 771 changed = 1; 772 if (rt->rt_expire != 0) { 773 if (dologging && log_arp_movements) { 774 hexncpy((u_char *)LLADDR(sdl), ifp->if_addrlen, 775 hexstr[0], HEX_NCPYLEN(ifp->if_addrlen), ":"); 776 hexncpy((u_char *)ar_sha(ah), ifp->if_addrlen, 777 hexstr[1], HEX_NCPYLEN(ifp->if_addrlen), ":"); 778 log(LOG_INFO, 779 "arp: %s moved from %s to %s on %s\n", 780 kinet_ntoa(isaddr, sbuf), hexstr[0], hexstr[1], 781 ifp->if_xname); 782 } 783 } else { 784 if (dologging && log_arp_permanent_modify) { 785 hexncpy((u_char *)ar_sha(ah), ifp->if_addrlen, 786 hexstr[0], HEX_NCPYLEN(ifp->if_addrlen), ":"); 787 log(LOG_ERR, 788 "arp: %s attempts to modify " 789 "permanent entry for %s on %s\n", 790 hexstr[0], kinet_ntoa(isaddr, sbuf), ifp->if_xname); 791 } 792 return changed; 793 } 794 } 795 /* 796 * sanity check for the address length. 797 * XXX this does not work for protocols with variable address 798 * length. -is 799 */ 800 if (dologging && sdl->sdl_alen && sdl->sdl_alen != ah->ar_hln) { 801 hexncpy((u_char *)ar_sha(ah), ifp->if_addrlen, 802 hexstr[0], HEX_NCPYLEN(ifp->if_addrlen), ":"); 803 log(LOG_WARNING, 804 "arp from %s: new addr len %d, was %d", 805 hexstr[0], ah->ar_hln, sdl->sdl_alen); 806 } 807 if (ifp->if_addrlen != ah->ar_hln) { 808 if (dologging) { 809 hexncpy((u_char *)ar_sha(ah), ifp->if_addrlen, 810 hexstr[0], HEX_NCPYLEN(ifp->if_addrlen), ":"); 811 log(LOG_WARNING, 812 "arp from %s: addr len: new %d, i/f %d " 813 "(ignored)", hexstr[0], 814 ah->ar_hln, ifp->if_addrlen); 815 } 816 return changed; 817 } 818 memcpy(LLADDR(sdl), ar_sha(ah), sdl->sdl_alen = ah->ar_hln); 819 if (rt->rt_expire != 0) { 820 if (rt->rt_expire != time_uptime + arpt_keep && 821 rt->rt_expire != time_uptime + arpt_keep - 1) { 822 rt->rt_expire = time_uptime + arpt_keep; 823 changed = 1; 824 } 825 } 826 if (rt->rt_flags & RTF_REJECT) { 827 rt->rt_flags &= ~RTF_REJECT; 828 changed = 1; 829 } 830 if (la->la_asked != 0) { 831 la->la_asked = 0; 832 changed = 1; 833 } 834 if (la->la_preempt != arp_maxtries) { 835 la->la_preempt = arp_maxtries; 836 changed = 1; 837 } 838 839 /* 840 * This particular cpu might have been holding an mbuf 841 * pending ARP resolution. If so, transmit the mbuf now. 842 */ 843 if (la->la_hold != NULL) { 844 struct mbuf *m = la->la_hold; 845 846 la->la_hold = NULL; 847 m_adj(m, sizeof(struct ether_header)); 848 ifp->if_output(ifp, m, rt_key(rt), rt); 849 changed = 1; 850 } 851 } 852 return changed; 853 } 854 855 /* 856 * Called from arpintr() - this routine is run from a single cpu. 857 */ 858 static void 859 in_arpinput(struct mbuf *m) 860 { 861 struct arphdr *ah; 862 struct ifnet *ifp = m->m_pkthdr.rcvif; 863 struct ifaddr_container *ifac; 864 struct in_ifaddr_container *iac; 865 struct in_ifaddr *ia = NULL; 866 struct in_addr isaddr, itaddr, myaddr; 867 uint8_t *enaddr = NULL; 868 int req_len; 869 int changed; 870 char hexstr[64], sbuf[INET_ADDRSTRLEN]; 871 872 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 873 if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) { 874 log(LOG_ERR, "in_arp: runt packet -- m_pullup failed\n"); 875 return; 876 } 877 878 ah = mtod(m, struct arphdr *); 879 memcpy(&isaddr, ar_spa(ah), sizeof isaddr); 880 memcpy(&itaddr, ar_tpa(ah), sizeof itaddr); 881 882 /* 883 * Check both target and sender IP addresses: 884 * 885 * If we receive the packet on the interface owning the address, 886 * then accept the address. 887 * 888 * For a bridge, we accept the address if the receive interface and 889 * the interface owning the address are on the same bridge, and 890 * use the bridge MAC as the is-at response. The bridge will be 891 * responsible for handling the packet. 892 * 893 * (0) Check target IP against CARP IPs 894 */ 895 #ifdef CARP 896 LIST_FOREACH(iac, INADDR_HASH(itaddr.s_addr), ia_hash) { 897 int is_match = 0, is_parent = 0; 898 899 ia = iac->ia; 900 901 /* Skip all ia's which don't match */ 902 if (itaddr.s_addr != ia->ia_addr.sin_addr.s_addr) 903 continue; 904 905 if (ia->ia_ifp->if_type != IFT_CARP) 906 continue; 907 908 if (carp_parent(ia->ia_ifp) == ifp) 909 is_parent = 1; 910 if (is_parent || ia->ia_ifp == ifp) 911 is_match = carp_iamatch(ia); 912 913 if (is_match) { 914 if (is_parent) { 915 /* 916 * The parent interface will also receive 917 * the ethernet broadcast packets, e.g. ARP 918 * REQUEST, so if we could find a CARP 919 * interface of the parent that could match 920 * the target IP address, we then drop the 921 * packets, which is delieverd to us through 922 * the parent interface. 923 */ 924 m_freem(m); 925 return; 926 } 927 goto match; 928 } 929 } 930 #endif /* CARP */ 931 932 /* 933 * (1) Check target IP against our local IPs 934 */ 935 LIST_FOREACH(iac, INADDR_HASH(itaddr.s_addr), ia_hash) { 936 ia = iac->ia; 937 938 /* Skip all ia's which don't match */ 939 if (itaddr.s_addr != ia->ia_addr.sin_addr.s_addr) 940 continue; 941 942 #ifdef CARP 943 /* CARP interfaces are checked in (0) */ 944 if (ia->ia_ifp->if_type == IFT_CARP) 945 continue; 946 #endif 947 948 if (ifp->if_bridge && ia->ia_ifp && 949 ifp->if_bridge == ia->ia_ifp->if_bridge) { 950 ifp = ether_bridge_interface(ifp); 951 goto match; 952 } 953 if (ia->ia_ifp && ia->ia_ifp->if_bridge && 954 ether_bridge_interface(ia->ia_ifp) == ifp) { 955 goto match; 956 } 957 if (ifp->if_bridge && ether_bridge_interface(ifp) == 958 ia->ia_ifp) { 959 goto match; 960 } 961 if (ia->ia_ifp == ifp) { 962 goto match; 963 } 964 } 965 966 /* 967 * (2) Check sender IP against our local IPs 968 */ 969 LIST_FOREACH(iac, INADDR_HASH(isaddr.s_addr), ia_hash) { 970 ia = iac->ia; 971 972 /* Skip all ia's which don't match */ 973 if (isaddr.s_addr != ia->ia_addr.sin_addr.s_addr) 974 continue; 975 976 if (ifp->if_bridge && ia->ia_ifp && 977 ifp->if_bridge == ia->ia_ifp->if_bridge) { 978 ifp = ether_bridge_interface(ifp); 979 goto match; 980 } 981 if (ia->ia_ifp && ia->ia_ifp->if_bridge && 982 ether_bridge_interface(ia->ia_ifp) == ifp) { 983 goto match; 984 } 985 if (ifp->if_bridge && ether_bridge_interface(ifp) == 986 ia->ia_ifp) { 987 goto match; 988 } 989 990 if (ia->ia_ifp == ifp) 991 goto match; 992 } 993 994 /* 995 * No match, use the first inet address on the receive interface 996 * as a dummy address for the rest of the function. 997 */ 998 TAILQ_FOREACH(ifac, &ifp->if_addrheads[mycpuid], ifa_link) { 999 struct ifaddr *ifa = ifac->ifa; 1000 1001 if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_INET) { 1002 ia = ifatoia(ifa); 1003 goto match; 1004 } 1005 } 1006 1007 /* 1008 * If we got here, we didn't find any suitable interface, 1009 * so drop the packet. 1010 */ 1011 m_freem(m); 1012 return; 1013 1014 match: 1015 if (!enaddr) 1016 enaddr = (uint8_t *)IF_LLADDR(ifp); 1017 myaddr = ia->ia_addr.sin_addr; 1018 if (!bcmp(ar_sha(ah), enaddr, ifp->if_addrlen)) { 1019 m_freem(m); /* it's from me, ignore it. */ 1020 return; 1021 } 1022 if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) { 1023 log(LOG_ERR, 1024 "arp: link address is broadcast for IP address %s!\n", 1025 kinet_ntoa(isaddr, sbuf)); 1026 m_freem(m); 1027 return; 1028 } 1029 if (isaddr.s_addr == myaddr.s_addr && myaddr.s_addr != 0) { 1030 hexncpy((u_char *)ar_sha(ah), ifp->if_addrlen, 1031 hexstr, HEX_NCPYLEN(ifp->if_addrlen), ":"); 1032 log(LOG_ERR, 1033 "arp: %s is using my IP address %s!\n", 1034 hexstr, kinet_ntoa(isaddr, sbuf)); 1035 itaddr = myaddr; 1036 goto reply; 1037 } 1038 if (ifp->if_flags & IFF_STATICARP) 1039 goto reply; 1040 1041 /* 1042 * When arp_restricted_match is true and the ARP response is not 1043 * specifically targetted to me, ignore it. Otherwise the entry 1044 * timeout may be updated for an old MAC. 1045 */ 1046 if (arp_restricted_match && itaddr.s_addr != myaddr.s_addr) { 1047 m_freem(m); 1048 return; 1049 } 1050 1051 /* 1052 * Update all CPU's routing tables with this ARP packet. 1053 * 1054 * However, we only need to generate rtmsg on CPU0. 1055 */ 1056 ASSERT_NETISR0; 1057 changed = arp_update_oncpu(m, isaddr.s_addr, 1058 itaddr.s_addr == myaddr.s_addr, 1059 RTL_REPORTMSG, TRUE); 1060 1061 if (netisr_ncpus > 1 && changed) { 1062 struct netmsg_inarp *msg = &m->m_hdr.mh_arpmsg; 1063 1064 netmsg_init(&msg->base, NULL, &netisr_apanic_rport, 1065 0, arp_update_msghandler); 1066 msg->m = m; 1067 msg->saddr = isaddr.s_addr; 1068 msg->taddr = itaddr.s_addr; 1069 msg->myaddr = myaddr.s_addr; 1070 lwkt_sendmsg(netisr_cpuport(1), &msg->base.lmsg); 1071 } else { 1072 goto reply; 1073 } 1074 1075 /* 1076 * Just return here; after all CPUs's routing tables are 1077 * properly updated by this ARP packet, an ARP reply will 1078 * be generated if appropriate. 1079 */ 1080 return; 1081 reply: 1082 in_arpreply(m, itaddr.s_addr, myaddr.s_addr); 1083 } 1084 1085 static void 1086 arp_reply_msghandler(netmsg_t msg) 1087 { 1088 struct netmsg_inarp *rmsg = (struct netmsg_inarp *)msg; 1089 1090 in_arpreply(rmsg->m, rmsg->taddr, rmsg->myaddr); 1091 /* Don't reply this netmsg; netmsg_inarp is embedded in mbuf */ 1092 } 1093 1094 static void 1095 arp_update_msghandler(netmsg_t msg) 1096 { 1097 struct netmsg_inarp *rmsg = (struct netmsg_inarp *)msg; 1098 int nextcpu; 1099 1100 ASSERT_NETISR_NCPUS(mycpuid); 1101 1102 /* 1103 * This message handler will be called on all of the APs; 1104 * no need to generate rtmsg on them. 1105 */ 1106 KASSERT(mycpuid > 0, ("arp update msg on cpu%d", mycpuid)); 1107 arp_update_oncpu(rmsg->m, rmsg->saddr, 1108 rmsg->taddr == rmsg->myaddr, 1109 RTL_DONTREPORT, FALSE); 1110 1111 nextcpu = mycpuid + 1; 1112 if (nextcpu < netisr_ncpus) { 1113 lwkt_forwardmsg(netisr_cpuport(nextcpu), &rmsg->base.lmsg); 1114 } else { 1115 struct mbuf *m = rmsg->m; 1116 in_addr_t saddr = rmsg->saddr; 1117 in_addr_t taddr = rmsg->taddr; 1118 in_addr_t myaddr = rmsg->myaddr; 1119 1120 /* 1121 * Dispatch this mbuf to netisr0 to perform ARP reply, 1122 * if appropriate. 1123 * NOTE: netmsg_inarp is embedded in this mbuf. 1124 */ 1125 netmsg_init(&rmsg->base, NULL, &netisr_apanic_rport, 1126 0, arp_reply_msghandler); 1127 rmsg->m = m; 1128 rmsg->saddr = saddr; 1129 rmsg->taddr = taddr; 1130 rmsg->myaddr = myaddr; 1131 lwkt_sendmsg(netisr_cpuport(0), &rmsg->base.lmsg); 1132 } 1133 } 1134 1135 static void 1136 in_arpreply(struct mbuf *m, in_addr_t taddr, in_addr_t myaddr) 1137 { 1138 struct ifnet *ifp = m->m_pkthdr.rcvif; 1139 const uint8_t *enaddr; 1140 struct arphdr *ah; 1141 struct sockaddr sa; 1142 struct ether_header *eh; 1143 1144 ASSERT_NETISR0; 1145 1146 ah = mtod(m, struct arphdr *); 1147 if (ntohs(ah->ar_op) != ARPOP_REQUEST) { 1148 m_freem(m); 1149 return; 1150 } 1151 1152 enaddr = (const uint8_t *)IF_LLADDR(ifp); 1153 if (taddr == myaddr) { 1154 /* I am the target */ 1155 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 1156 memcpy(ar_sha(ah), enaddr, ah->ar_hln); 1157 } else { 1158 struct llinfo_arp *la; 1159 struct rtentry *rt; 1160 1161 la = arplookup(taddr, FALSE, RTL_DONTREPORT, SIN_PROXY); 1162 if (la == NULL) { 1163 struct sockaddr_in sin; 1164 #ifdef DEBUG_PROXY 1165 char tbuf[INET_ADDRSTRLEN]; 1166 #endif 1167 1168 if (!arp_proxyall) { 1169 m_freem(m); 1170 return; 1171 } 1172 1173 bzero(&sin, sizeof sin); 1174 sin.sin_family = AF_INET; 1175 sin.sin_len = sizeof sin; 1176 sin.sin_addr.s_addr = taddr; 1177 1178 rt = rtpurelookup((struct sockaddr *)&sin); 1179 if (rt == NULL) { 1180 m_freem(m); 1181 return; 1182 } 1183 --rt->rt_refcnt; 1184 /* 1185 * Don't send proxies for nodes on the same interface 1186 * as this one came out of, or we'll get into a fight 1187 * over who claims what Ether address. 1188 */ 1189 if (rt->rt_ifp == ifp) { 1190 m_freem(m); 1191 return; 1192 } 1193 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 1194 memcpy(ar_sha(ah), enaddr, ah->ar_hln); 1195 #ifdef DEBUG_PROXY 1196 kprintf("arp: proxying for %s\n", 1197 kinet_ntoa(itaddr, tbuf)); 1198 #endif 1199 } else { 1200 struct sockaddr_dl *sdl; 1201 1202 rt = la->la_rt; 1203 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 1204 sdl = SDL(rt->rt_gateway); 1205 memcpy(ar_sha(ah), LLADDR(sdl), ah->ar_hln); 1206 } 1207 } 1208 1209 memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln); 1210 memcpy(ar_spa(ah), &taddr, ah->ar_pln); 1211 ah->ar_op = htons(ARPOP_REPLY); 1212 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 1213 switch (ifp->if_type) { 1214 case IFT_ETHER: 1215 /* 1216 * May not be correct for types not explictly 1217 * listed, but it is our best guess. 1218 */ 1219 default: 1220 eh = (struct ether_header *)sa.sa_data; 1221 memcpy(eh->ether_dhost, ar_tha(ah), sizeof eh->ether_dhost); 1222 eh->ether_type = htons(ETHERTYPE_ARP); 1223 break; 1224 } 1225 sa.sa_family = AF_UNSPEC; 1226 sa.sa_len = sizeof sa; 1227 ifp->if_output(ifp, m, &sa, NULL); 1228 } 1229 1230 #endif /* INET */ 1231 1232 /* 1233 * Free an arp entry. If the arp entry is actively referenced or represents 1234 * a static entry we only clear it back to an unresolved state, otherwise 1235 * we destroy the entry entirely. 1236 * 1237 * Note that static entries are created when route add ... -interface is used 1238 * to create an interface route to a (direct) destination. 1239 */ 1240 static void 1241 arptfree(struct llinfo_arp *la) 1242 { 1243 struct rtentry *rt = la->la_rt; 1244 struct sockaddr_dl *sdl; 1245 1246 if (rt == NULL) 1247 panic("arptfree"); 1248 sdl = SDL(rt->rt_gateway); 1249 if (sdl != NULL && 1250 ((rt->rt_refcnt > 0 && sdl->sdl_family == AF_LINK) || 1251 (rt->rt_flags & RTF_STATIC))) { 1252 sdl->sdl_alen = 0; 1253 la->la_preempt = la->la_asked = 0; 1254 rt->rt_flags &= ~RTF_REJECT; 1255 return; 1256 } 1257 rtrequest(RTM_DELETE, rt_key(rt), NULL, rt_mask(rt), 0, NULL); 1258 } 1259 1260 /* 1261 * Lookup or enter a new address in arptab. 1262 */ 1263 static struct llinfo_arp * 1264 arplookup(in_addr_t addr, boolean_t create, boolean_t generate_report, 1265 boolean_t proxy) 1266 { 1267 struct rtentry *rt; 1268 struct sockaddr_inarp sin = { sizeof sin, AF_INET }; 1269 const char *why = NULL; 1270 1271 /* Check ARP probes, e.g. from Cisco switches. */ 1272 if (addr == INADDR_ANY && arp_ignore_probes) 1273 return (NULL); 1274 1275 sin.sin_addr.s_addr = addr; 1276 sin.sin_other = proxy ? SIN_PROXY : 0; 1277 if (create) { 1278 rt = _rtlookup((struct sockaddr *)&sin, 1279 generate_report, RTL_DOCLONE); 1280 } else { 1281 rt = rtpurelookup((struct sockaddr *)&sin); 1282 } 1283 if (rt == NULL) 1284 return (NULL); 1285 rt->rt_refcnt--; 1286 1287 if (rt->rt_flags & RTF_GATEWAY) 1288 why = "host is not on local network"; 1289 else if (!(rt->rt_flags & RTF_LLINFO)) 1290 why = "could not allocate llinfo"; 1291 else if (rt->rt_gateway->sa_family != AF_LINK) 1292 why = "gateway route is not ours"; 1293 1294 if (why) { 1295 if (create && log_arp_creation_failure) { 1296 char abuf[INET_ADDRSTRLEN]; 1297 1298 log(LOG_DEBUG, "arplookup %s failed: %s\n", 1299 kinet_ntoa(sin.sin_addr, abuf), why); 1300 } 1301 if (rt->rt_refcnt <= 0 && (rt->rt_flags & RTF_WASCLONED)) { 1302 /* No references to this route. Purge it. */ 1303 rtrequest(RTM_DELETE, rt_key(rt), rt->rt_gateway, 1304 rt_mask(rt), rt->rt_flags, NULL); 1305 } 1306 return (NULL); 1307 } 1308 return (rt->rt_llinfo); 1309 } 1310 1311 void 1312 arp_ifinit(struct ifnet *ifp, struct ifaddr *ifa) 1313 { 1314 ifa->ifa_rtrequest = arp_rtrequest; 1315 ifa->ifa_flags |= RTF_CLONING; 1316 } 1317 1318 void 1319 arp_gratuitous(struct ifnet *ifp, struct ifaddr *ifa) 1320 { 1321 if (IA_SIN(ifa)->sin_addr.s_addr != INADDR_ANY) { 1322 if (IN_NETISR_NCPUS(mycpuid)) { 1323 arprequest(ifp, &IA_SIN(ifa)->sin_addr, 1324 &IA_SIN(ifa)->sin_addr, NULL); 1325 } else { 1326 arprequest_async(ifp, &IA_SIN(ifa)->sin_addr, 1327 &IA_SIN(ifa)->sin_addr, NULL); 1328 } 1329 } 1330 } 1331 1332 static void 1333 arp_ifaddr(void *arg __unused, struct ifnet *ifp, 1334 enum ifaddr_event event, struct ifaddr *ifa) 1335 { 1336 if (ifa->ifa_rtrequest != arp_rtrequest) /* XXX need a generic way */ 1337 return; 1338 if (ifa->ifa_addr->sa_family != AF_INET) 1339 return; 1340 if (event == IFADDR_EVENT_DELETE) 1341 return; 1342 1343 /* 1344 * - CARP interfaces will take care of gratuitous ARP themselves. 1345 * - If we are the CARP interface's parent, don't send gratuitous 1346 * ARP to avoid unnecessary confusion. 1347 */ 1348 #ifdef CARP 1349 if (ifp->if_type != IFT_CARP && ifp->if_carp == NULL) 1350 #endif 1351 { 1352 arp_gratuitous(ifp, ifa); 1353 } 1354 } 1355 1356 static void 1357 arp_init_dispatch(netmsg_t nm) 1358 { 1359 struct arp_pcpu_data *ad; 1360 1361 ASSERT_NETISR_NCPUS(mycpuid); 1362 1363 ad = kmalloc(sizeof(*ad), M_ARP, M_WAITOK | M_ZERO); 1364 1365 LIST_INIT(&ad->llinfo_list); 1366 callout_init_mp(&ad->timer_ch); 1367 netmsg_init(&ad->timer_nmsg, NULL, &netisr_adone_rport, 1368 MSGF_PRIORITY, arptimer_dispatch); 1369 ad->timer_nmsg.lmsg.u.ms_resultp = ad; 1370 1371 arp_data[mycpuid] = ad; 1372 1373 callout_reset(&ad->timer_ch, hz, arptimer, &ad->timer_nmsg); 1374 1375 netisr_forwardmsg(&nm->base, mycpuid + 1); 1376 } 1377 1378 static void 1379 arp_init(void) 1380 { 1381 struct netmsg_base nm; 1382 1383 netmsg_init(&nm, NULL, &curthread->td_msgport, 0, arp_init_dispatch); 1384 netisr_domsg_global(&nm); 1385 1386 netisr_register(NETISR_ARP, arpintr, NULL); 1387 1388 EVENTHANDLER_REGISTER(ifaddr_event, arp_ifaddr, NULL, 1389 EVENTHANDLER_PRI_LAST); 1390 } 1391 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0); 1392