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. All advertising materials mentioning features or use of this software 46 * must display the following acknowledgement: 47 * This product includes software developed by the University of 48 * California, Berkeley and its contributors. 49 * 4. Neither the name of the University nor the names of its contributors 50 * may be used to endorse or promote products derived from this software 51 * without specific prior written permission. 52 * 53 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 54 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 55 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 56 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 57 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 58 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 59 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 60 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 61 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 62 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 63 * SUCH DAMAGE. 64 * 65 * @(#)if_ether.c 8.1 (Berkeley) 6/10/93 66 * $FreeBSD: src/sys/netinet/if_ether.c,v 1.64.2.23 2003/04/11 07:23:15 fjoe Exp $ 67 * $DragonFly: src/sys/netinet/if_ether.c,v 1.57 2008/10/07 22:30:31 thomas Exp $ 68 */ 69 70 /* 71 * Ethernet address resolution protocol. 72 * TODO: 73 * add "inuse/lock" bit (or ref. count) along with valid bit 74 */ 75 76 #include "opt_inet.h" 77 #include "opt_carp.h" 78 79 #include <sys/param.h> 80 #include <sys/kernel.h> 81 #include <sys/queue.h> 82 #include <sys/sysctl.h> 83 #include <sys/systm.h> 84 #include <sys/mbuf.h> 85 #include <sys/malloc.h> 86 #include <sys/socket.h> 87 #include <sys/syslog.h> 88 #include <sys/lock.h> 89 90 #include <net/if.h> 91 #include <net/if_dl.h> 92 #include <net/if_types.h> 93 #include <net/route.h> 94 #include <net/netisr.h> 95 #include <net/if_llc.h> 96 97 #include <netinet/in.h> 98 #include <netinet/in_var.h> 99 #include <netinet/if_ether.h> 100 101 #include <sys/thread2.h> 102 #include <sys/msgport2.h> 103 #include <net/netmsg2.h> 104 105 #ifdef CARP 106 #include <netinet/ip_carp.h> 107 #endif 108 109 #define SIN(s) ((struct sockaddr_in *)s) 110 #define SDL(s) ((struct sockaddr_dl *)s) 111 112 SYSCTL_DECL(_net_link_ether); 113 SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, ""); 114 115 /* timer values */ 116 static int arpt_prune = (5*60*1); /* walk list every 5 minutes */ 117 static int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */ 118 static int arpt_down = 20; /* once declared down, don't send for 20 sec */ 119 120 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, prune_intvl, CTLFLAG_RW, 121 &arpt_prune, 0, ""); 122 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW, 123 &arpt_keep, 0, ""); 124 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, host_down_time, CTLFLAG_RW, 125 &arpt_down, 0, ""); 126 127 #define rt_expire rt_rmx.rmx_expire 128 129 struct llinfo_arp { 130 LIST_ENTRY(llinfo_arp) la_le; 131 struct rtentry *la_rt; 132 struct mbuf *la_hold; /* last packet until resolved/timeout */ 133 u_short la_preempt; /* countdown for pre-expiry arps */ 134 u_short la_asked; /* #times we QUERIED following expiration */ 135 }; 136 137 static LIST_HEAD(, llinfo_arp) llinfo_arp_list[MAXCPU]; 138 139 static int arp_maxtries = 5; 140 static int useloopback = 1; /* use loopback interface for local traffic */ 141 static int arp_proxyall = 0; 142 143 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW, 144 &arp_maxtries, 0, ""); 145 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW, 146 &useloopback, 0, ""); 147 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW, 148 &arp_proxyall, 0, ""); 149 150 static int arp_mpsafe = 0; 151 TUNABLE_INT("net.link.ether.inet.arp_mpsafe", &arp_mpsafe); 152 153 static void arp_rtrequest(int, struct rtentry *, struct rt_addrinfo *); 154 static void arprequest(struct ifnet *, struct in_addr *, struct in_addr *, 155 const u_char *); 156 static void arprequest_async(struct ifnet *, struct in_addr *, 157 struct in_addr *, const u_char *); 158 static void arpintr(struct netmsg *); 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); 163 #ifdef INET 164 static void in_arpinput(struct mbuf *); 165 #endif 166 167 static struct callout arptimer_ch[MAXCPU]; 168 169 /* 170 * Timeout routine. Age arp_tab entries periodically. 171 */ 172 /* ARGSUSED */ 173 static void 174 arptimer(void *ignored_arg) 175 { 176 struct llinfo_arp *la, *nla; 177 178 crit_enter(); 179 LIST_FOREACH_MUTABLE(la, &llinfo_arp_list[mycpuid], la_le, nla) { 180 if (la->la_rt->rt_expire && la->la_rt->rt_expire <= time_second) 181 arptfree(la); 182 } 183 callout_reset(&arptimer_ch[mycpuid], arpt_prune * hz, arptimer, NULL); 184 crit_exit(); 185 } 186 187 /* 188 * Parallel to llc_rtrequest. 189 */ 190 static void 191 arp_rtrequest(int req, struct rtentry *rt, struct rt_addrinfo *info) 192 { 193 struct sockaddr *gate = rt->rt_gateway; 194 struct llinfo_arp *la = rt->rt_llinfo; 195 196 struct sockaddr_dl null_sdl = { sizeof null_sdl, AF_LINK }; 197 static boolean_t arpinit_done[MAXCPU]; 198 199 if (!arpinit_done[mycpuid]) { 200 arpinit_done[mycpuid] = TRUE; 201 callout_init(&arptimer_ch[mycpuid]); 202 callout_reset(&arptimer_ch[mycpuid], hz, arptimer, NULL); 203 } 204 if (rt->rt_flags & RTF_GATEWAY) 205 return; 206 207 switch (req) { 208 case RTM_ADD: 209 /* 210 * XXX: If this is a manually added route to interface 211 * such as older version of routed or gated might provide, 212 * restore cloning bit. 213 */ 214 if (!(rt->rt_flags & RTF_HOST) && 215 SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff) 216 rt->rt_flags |= RTF_CLONING; 217 if (rt->rt_flags & RTF_CLONING) { 218 /* 219 * Case 1: This route should come from a route to iface. 220 */ 221 rt_setgate(rt, rt_key(rt), 222 (struct sockaddr *)&null_sdl); 223 gate = rt->rt_gateway; 224 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 225 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 226 rt->rt_expire = time_second; 227 break; 228 } 229 /* Announce a new entry if requested. */ 230 if (rt->rt_flags & RTF_ANNOUNCE) { 231 arprequest_async(rt->rt_ifp, 232 &SIN(rt_key(rt))->sin_addr, 233 &SIN(rt_key(rt))->sin_addr, 234 LLADDR(SDL(gate))); 235 } 236 /*FALLTHROUGH*/ 237 case RTM_RESOLVE: 238 if (gate->sa_family != AF_LINK || 239 gate->sa_len < sizeof(struct sockaddr_dl)) { 240 log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n"); 241 break; 242 } 243 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 244 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 245 if (la != NULL) 246 break; /* This happens on a route change */ 247 /* 248 * Case 2: This route may come from cloning, or a manual route 249 * add with a LL address. 250 */ 251 R_Malloc(la, struct llinfo_arp *, sizeof *la); 252 rt->rt_llinfo = la; 253 if (la == NULL) { 254 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); 255 break; 256 } 257 bzero(la, sizeof *la); 258 la->la_rt = rt; 259 rt->rt_flags |= RTF_LLINFO; 260 LIST_INSERT_HEAD(&llinfo_arp_list[mycpuid], la, la_le); 261 262 #ifdef INET 263 /* 264 * This keeps the multicast addresses from showing up 265 * in `arp -a' listings as unresolved. It's not actually 266 * functional. Then the same for broadcast. 267 */ 268 if (IN_MULTICAST(ntohl(SIN(rt_key(rt))->sin_addr.s_addr))) { 269 ETHER_MAP_IP_MULTICAST(&SIN(rt_key(rt))->sin_addr, 270 LLADDR(SDL(gate))); 271 SDL(gate)->sdl_alen = 6; 272 rt->rt_expire = 0; 273 } 274 if (in_broadcast(SIN(rt_key(rt))->sin_addr, rt->rt_ifp)) { 275 memcpy(LLADDR(SDL(gate)), rt->rt_ifp->if_broadcastaddr, 276 rt->rt_ifp->if_addrlen); 277 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen; 278 rt->rt_expire = 0; 279 } 280 #endif 281 282 if (SIN(rt_key(rt))->sin_addr.s_addr == 283 (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) { 284 /* 285 * This test used to be 286 * if (loif.if_flags & IFF_UP) 287 * It allowed local traffic to be forced 288 * through the hardware by configuring the 289 * loopback down. However, it causes problems 290 * during network configuration for boards 291 * that can't receive packets they send. It 292 * is now necessary to clear "useloopback" and 293 * remove the route to force traffic out to 294 * the hardware. 295 */ 296 rt->rt_expire = 0; 297 bcopy(IF_LLADDR(rt->rt_ifp), LLADDR(SDL(gate)), 298 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen); 299 if (useloopback) 300 rt->rt_ifp = loif; 301 } 302 break; 303 304 case RTM_DELETE: 305 if (la == NULL) 306 break; 307 LIST_REMOVE(la, la_le); 308 rt->rt_llinfo = NULL; 309 rt->rt_flags &= ~RTF_LLINFO; 310 if (la->la_hold != NULL) 311 m_freem(la->la_hold); 312 Free(la); 313 break; 314 } 315 } 316 317 static struct mbuf * 318 arpreq_alloc(struct ifnet *ifp, struct in_addr *sip, struct in_addr *tip, 319 const u_char *enaddr) 320 { 321 struct mbuf *m; 322 struct arphdr *ah; 323 u_short ar_hrd; 324 325 if ((m = m_gethdr(MB_DONTWAIT, MT_DATA)) == NULL) 326 return NULL; 327 m->m_pkthdr.rcvif = NULL; 328 329 switch (ifp->if_type) { 330 case IFT_ETHER: 331 /* 332 * This may not be correct for types not explicitly 333 * listed, but this is our best guess 334 */ 335 default: 336 ar_hrd = htons(ARPHRD_ETHER); 337 338 m->m_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 339 m->m_pkthdr.len = m->m_len; 340 MH_ALIGN(m, m->m_len); 341 342 ah = mtod(m, struct arphdr *); 343 break; 344 } 345 346 ah->ar_hrd = ar_hrd; 347 ah->ar_pro = htons(ETHERTYPE_IP); 348 ah->ar_hln = ifp->if_addrlen; /* hardware address length */ 349 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 350 ah->ar_op = htons(ARPOP_REQUEST); 351 memcpy(ar_sha(ah), enaddr, ah->ar_hln); 352 memset(ar_tha(ah), 0, ah->ar_hln); 353 memcpy(ar_spa(ah), sip, ah->ar_pln); 354 memcpy(ar_tpa(ah), tip, ah->ar_pln); 355 356 return m; 357 } 358 359 static void 360 arpreq_send(struct ifnet *ifp, struct mbuf *m) 361 { 362 struct sockaddr sa; 363 struct ether_header *eh; 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 eh = (struct ether_header *)sa.sa_data; 373 /* if_output() will not swap */ 374 eh->ether_type = htons(ETHERTYPE_ARP); 375 memcpy(eh->ether_dhost, ifp->if_broadcastaddr, ifp->if_addrlen); 376 break; 377 } 378 379 sa.sa_family = AF_UNSPEC; 380 sa.sa_len = sizeof(sa); 381 ifp->if_output(ifp, m, &sa, NULL); 382 } 383 384 static void 385 arpreq_send_handler(struct netmsg *nmsg) 386 { 387 struct mbuf *m = ((struct netmsg_packet *)nmsg)->nm_packet; 388 struct ifnet *ifp = nmsg->nm_lmsg.u.ms_resultp; 389 390 arpreq_send(ifp, m); 391 /* nmsg was embedded in the mbuf, do not reply! */ 392 } 393 394 /* 395 * Broadcast an ARP request. Caller specifies: 396 * - arp header source ip address 397 * - arp header target ip address 398 * - arp header source ethernet address 399 * 400 * NOTE: Caller MUST NOT hold ifp's serializer 401 */ 402 static void 403 arprequest(struct ifnet *ifp, struct in_addr *sip, struct in_addr *tip, 404 const u_char *enaddr) 405 { 406 struct mbuf *m; 407 408 m = arpreq_alloc(ifp, sip, tip, enaddr); 409 if (m == NULL) 410 return; 411 arpreq_send(ifp, m); 412 } 413 414 /* 415 * Same as arprequest(), except: 416 * - Caller is allowed to hold ifp's serializer 417 * - Network output is done in TDF_NETWORK kernel thread 418 */ 419 static void 420 arprequest_async(struct ifnet *ifp, struct in_addr *sip, struct in_addr *tip, 421 const u_char *enaddr) 422 { 423 struct mbuf *m; 424 struct netmsg_packet *pmsg; 425 426 m = arpreq_alloc(ifp, sip, tip, enaddr); 427 if (m == NULL) 428 return; 429 430 pmsg = &m->m_hdr.mh_netmsg; 431 netmsg_init(&pmsg->nm_netmsg, &netisr_apanic_rport, 0, 432 arpreq_send_handler); 433 pmsg->nm_packet = m; 434 pmsg->nm_netmsg.nm_lmsg.u.ms_resultp = ifp; 435 436 lwkt_sendmsg(cpu_portfn(mycpuid), &pmsg->nm_netmsg.nm_lmsg); 437 } 438 439 /* 440 * Resolve an IP address into an ethernet address. If success, 441 * desten is filled in. If there is no entry in arptab, 442 * set one up and broadcast a request for the IP address. 443 * Hold onto this mbuf and resend it once the address 444 * is finally resolved. A return value of 1 indicates 445 * that desten has been filled in and the packet should be sent 446 * normally; a 0 return indicates that the packet has been 447 * taken over here, either now or for later transmission. 448 */ 449 int 450 arpresolve(struct ifnet *ifp, struct rtentry *rt0, struct mbuf *m, 451 struct sockaddr *dst, u_char *desten) 452 { 453 struct rtentry *rt; 454 struct llinfo_arp *la = NULL; 455 struct sockaddr_dl *sdl; 456 457 if (m->m_flags & M_BCAST) { /* broadcast */ 458 memcpy(desten, ifp->if_broadcastaddr, ifp->if_addrlen); 459 return (1); 460 } 461 if (m->m_flags & M_MCAST) {/* multicast */ 462 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); 463 return (1); 464 } 465 if (rt0 != NULL) { 466 if (rt_llroute(dst, rt0, &rt) != 0) { 467 m_freem(m); 468 return 0; 469 } 470 la = rt->rt_llinfo; 471 } 472 if (la == NULL) { 473 la = arplookup(SIN(dst)->sin_addr.s_addr, TRUE, FALSE); 474 if (la != NULL) 475 rt = la->la_rt; 476 } 477 if (la == NULL || rt == NULL) { 478 log(LOG_DEBUG, "arpresolve: can't allocate llinfo for %s%s%s\n", 479 inet_ntoa(SIN(dst)->sin_addr), la ? "la" : " ", 480 rt ? "rt" : ""); 481 m_freem(m); 482 return (0); 483 } 484 sdl = SDL(rt->rt_gateway); 485 /* 486 * Check the address family and length is valid, the address 487 * is resolved; otherwise, try to resolve. 488 */ 489 if ((rt->rt_expire == 0 || rt->rt_expire > time_second) && 490 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 491 /* 492 * If entry has an expiry time and it is approaching, 493 * see if we need to send an ARP request within this 494 * arpt_down interval. 495 */ 496 if ((rt->rt_expire != 0) && 497 (time_second + la->la_preempt > rt->rt_expire)) { 498 arprequest(ifp, 499 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 500 &SIN(dst)->sin_addr, 501 IF_LLADDR(ifp)); 502 la->la_preempt--; 503 } 504 505 bcopy(LLADDR(sdl), desten, sdl->sdl_alen); 506 return 1; 507 } 508 /* 509 * If ARP is disabled on this interface, stop. 510 * XXX 511 * Probably should not allocate empty llinfo struct if we are 512 * not going to be sending out an arp request. 513 */ 514 if (ifp->if_flags & IFF_NOARP) { 515 m_freem(m); 516 return (0); 517 } 518 /* 519 * There is an arptab entry, but no ethernet address 520 * response yet. Replace the held mbuf with this 521 * latest one. 522 */ 523 if (la->la_hold != NULL) 524 m_freem(la->la_hold); 525 la->la_hold = m; 526 if (rt->rt_expire || ((rt->rt_flags & RTF_STATIC) && !sdl->sdl_alen)) { 527 rt->rt_flags &= ~RTF_REJECT; 528 if (la->la_asked == 0 || rt->rt_expire != time_second) { 529 rt->rt_expire = time_second; 530 if (la->la_asked++ < arp_maxtries) { 531 arprequest(ifp, 532 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 533 &SIN(dst)->sin_addr, 534 IF_LLADDR(ifp)); 535 } else { 536 rt->rt_flags |= RTF_REJECT; 537 rt->rt_expire += arpt_down; 538 la->la_asked = 0; 539 la->la_preempt = arp_maxtries; 540 } 541 } 542 } 543 return (0); 544 } 545 546 /* 547 * Common length and type checks are done here, 548 * then the protocol-specific routine is called. 549 */ 550 static void 551 arpintr(struct netmsg *msg) 552 { 553 struct mbuf *m = ((struct netmsg_packet *)msg)->nm_packet; 554 struct arphdr *ar; 555 u_short ar_hrd; 556 557 if (m->m_len < sizeof(struct arphdr) && 558 (m = m_pullup(m, sizeof(struct arphdr))) == NULL) { 559 log(LOG_ERR, "arp: runt packet -- m_pullup failed\n"); 560 return; 561 } 562 ar = mtod(m, struct arphdr *); 563 564 ar_hrd = ntohs(ar->ar_hrd); 565 if (ar_hrd != ARPHRD_ETHER && ar_hrd != ARPHRD_IEEE802) { 566 log(LOG_ERR, "arp: unknown hardware address format (0x%2D)\n", 567 (unsigned char *)&ar->ar_hrd, ""); 568 m_freem(m); 569 return; 570 } 571 572 if (m->m_pkthdr.len < arphdr_len(ar)) { 573 if ((m = m_pullup(m, arphdr_len(ar))) == NULL) { 574 log(LOG_ERR, "arp: runt packet\n"); 575 return; 576 } 577 ar = mtod(m, struct arphdr *); 578 } 579 580 switch (ntohs(ar->ar_pro)) { 581 #ifdef INET 582 case ETHERTYPE_IP: 583 in_arpinput(m); 584 return; 585 #endif 586 } 587 m_freem(m); 588 /* msg was embedded in the mbuf, do not reply! */ 589 } 590 591 #ifdef INET 592 /* 593 * ARP for Internet protocols on 10 Mb/s Ethernet. 594 * Algorithm is that given in RFC 826. 595 * In addition, a sanity check is performed on the sender 596 * protocol address, to catch impersonators. 597 * We no longer handle negotiations for use of trailer protocol: 598 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 599 * along with IP replies if we wanted trailers sent to us, 600 * and also sent them in response to IP replies. 601 * This allowed either end to announce the desire to receive 602 * trailer packets. 603 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 604 * but formerly didn't normally send requests. 605 */ 606 static int log_arp_wrong_iface = 1; 607 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW, 608 &log_arp_wrong_iface, 0, 609 "log arp packets arriving on the wrong interface"); 610 611 static void 612 arp_update_oncpu(struct mbuf *m, in_addr_t saddr, boolean_t create, 613 boolean_t dologging) 614 { 615 struct arphdr *ah = mtod(m, struct arphdr *); 616 struct ifnet *ifp = m->m_pkthdr.rcvif; 617 struct llinfo_arp *la; 618 struct sockaddr_dl *sdl; 619 struct rtentry *rt; 620 621 la = arplookup(saddr, create, FALSE); 622 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { 623 struct in_addr isaddr = { saddr }; 624 625 /* the following is not an error when doing bridging */ 626 if (rt->rt_ifp != ifp) { 627 if (dologging && log_arp_wrong_iface) { 628 log(LOG_ERR, 629 "arp: %s is on %s " 630 "but got reply from %*D on %s\n", 631 inet_ntoa(isaddr), 632 rt->rt_ifp->if_xname, 633 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 634 ifp->if_xname); 635 } 636 return; 637 } 638 if (sdl->sdl_alen && 639 bcmp(ar_sha(ah), LLADDR(sdl), sdl->sdl_alen)) { 640 if (rt->rt_expire != 0) { 641 if (dologging) { 642 log(LOG_INFO, 643 "arp: %s moved from %*D to %*D on %s\n", 644 inet_ntoa(isaddr), 645 ifp->if_addrlen, (u_char *)LLADDR(sdl), 646 ":", ifp->if_addrlen, 647 (u_char *)ar_sha(ah), ":", 648 ifp->if_xname); 649 } 650 } else { 651 if (dologging) { 652 log(LOG_ERR, 653 "arp: %*D attempts to modify " 654 "permanent entry for %s on %s\n", 655 ifp->if_addrlen, (u_char *)ar_sha(ah), 656 ":", inet_ntoa(isaddr), ifp->if_xname); 657 } 658 return; 659 } 660 } 661 /* 662 * sanity check for the address length. 663 * XXX this does not work for protocols with variable address 664 * length. -is 665 */ 666 if (dologging && sdl->sdl_alen && sdl->sdl_alen != ah->ar_hln) { 667 log(LOG_WARNING, 668 "arp from %*D: new addr len %d, was %d", 669 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 670 ah->ar_hln, sdl->sdl_alen); 671 } 672 if (ifp->if_addrlen != ah->ar_hln) { 673 if (dologging) { 674 log(LOG_WARNING, 675 "arp from %*D: addr len: new %d, i/f %d " 676 "(ignored)", 677 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 678 ah->ar_hln, ifp->if_addrlen); 679 } 680 return; 681 } 682 memcpy(LLADDR(sdl), ar_sha(ah), sdl->sdl_alen = ah->ar_hln); 683 if (rt->rt_expire != 0) 684 rt->rt_expire = time_second + arpt_keep; 685 rt->rt_flags &= ~RTF_REJECT; 686 la->la_asked = 0; 687 la->la_preempt = arp_maxtries; 688 689 /* 690 * This particular cpu might have been holding an mbuf 691 * pending ARP resolution. If so, transmit the mbuf now. 692 */ 693 if (la->la_hold != NULL) { 694 m_adj(la->la_hold, sizeof(struct ether_header)); 695 ifp->if_output(ifp, la->la_hold, rt_key(rt), rt); 696 la->la_hold = NULL; 697 } 698 } 699 } 700 701 #ifdef SMP 702 703 struct netmsg_arp_update { 704 struct netmsg netmsg; 705 struct mbuf *m; 706 in_addr_t saddr; 707 boolean_t create; 708 }; 709 710 static void arp_update_msghandler(struct netmsg *); 711 712 #endif 713 714 /* 715 * Called from arpintr() - this routine is run from a single cpu. 716 */ 717 static void 718 in_arpinput(struct mbuf *m) 719 { 720 struct arphdr *ah; 721 struct ifnet *ifp = m->m_pkthdr.rcvif; 722 struct ether_header *eh; 723 struct rtentry *rt; 724 struct ifaddr_container *ifac; 725 struct in_ifaddr_container *iac; 726 struct in_ifaddr *ia; 727 struct sockaddr sa; 728 struct in_addr isaddr, itaddr, myaddr; 729 #ifdef SMP 730 struct netmsg_arp_update msg; 731 #endif 732 u_int8_t *enaddr = NULL; 733 int op; 734 int req_len; 735 736 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 737 if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) { 738 log(LOG_ERR, "in_arp: runt packet -- m_pullup failed\n"); 739 return; 740 } 741 742 ah = mtod(m, struct arphdr *); 743 op = ntohs(ah->ar_op); 744 memcpy(&isaddr, ar_spa(ah), sizeof isaddr); 745 memcpy(&itaddr, ar_tpa(ah), sizeof itaddr); 746 /* 747 * Check both target and sender IP addresses: 748 * 749 * If we receive the packet on the interface owning the address, 750 * then accept the address. 751 * 752 * For a bridge, we accept the address if the receive interface and 753 * the interface owning the address are on the same bridge. 754 * (This will change slightly when we have clusters of interfaces). 755 */ 756 LIST_FOREACH(iac, INADDR_HASH(itaddr.s_addr), ia_hash) { 757 ia = iac->ia; 758 759 /* Skip all ia's which don't match */ 760 if (itaddr.s_addr != ia->ia_addr.sin_addr.s_addr) 761 continue; 762 763 if (ia->ia_ifp == ifp) 764 goto match; 765 766 if (ifp->if_bridge && ia->ia_ifp && 767 ifp->if_bridge == ia->ia_ifp->if_bridge) 768 goto match; 769 770 #ifdef CARP 771 /* 772 * If the interface does not match, but the recieving interface 773 * is part of carp, we call carp_iamatch to see if this is a 774 * request for the virtual host ip. 775 * XXX: This is really ugly! 776 */ 777 if (ifp->if_carp != NULL) { 778 get_mplock(); 779 if (ifp->if_carp != NULL && 780 carp_iamatch(ifp->if_carp, ia, &isaddr, &enaddr)) { 781 rel_mplock(); 782 goto match; 783 } 784 rel_mplock(); 785 } 786 #endif 787 } 788 LIST_FOREACH(iac, INADDR_HASH(isaddr.s_addr), ia_hash) { 789 ia = iac->ia; 790 791 /* Skip all ia's which don't match */ 792 if (isaddr.s_addr != ia->ia_addr.sin_addr.s_addr) 793 continue; 794 795 if (ia->ia_ifp == ifp) 796 goto match; 797 798 if (ifp->if_bridge && ia->ia_ifp && 799 ifp->if_bridge == ia->ia_ifp->if_bridge) 800 goto match; 801 } 802 /* 803 * No match, use the first inet address on the receive interface 804 * as a dummy address for the rest of the function. 805 */ 806 TAILQ_FOREACH(ifac, &ifp->if_addrheads[mycpuid], ifa_link) { 807 struct ifaddr *ifa = ifac->ifa; 808 809 if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_INET) { 810 ia = ifatoia(ifa); 811 goto match; 812 } 813 } 814 /* 815 * If we got here, we didn't find any suitable interface, 816 * so drop the packet. 817 */ 818 m_freem(m); 819 return; 820 821 match: 822 if (!enaddr) 823 enaddr = (u_int8_t *)IF_LLADDR(ifp); 824 myaddr = ia->ia_addr.sin_addr; 825 if (!bcmp(ar_sha(ah), enaddr, ifp->if_addrlen)) { 826 m_freem(m); /* it's from me, ignore it. */ 827 return; 828 } 829 if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) { 830 log(LOG_ERR, 831 "arp: link address is broadcast for IP address %s!\n", 832 inet_ntoa(isaddr)); 833 m_freem(m); 834 return; 835 } 836 if (isaddr.s_addr == myaddr.s_addr && myaddr.s_addr != 0) { 837 log(LOG_ERR, 838 "arp: %*D is using my IP address %s!\n", 839 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 840 inet_ntoa(isaddr)); 841 itaddr = myaddr; 842 goto reply; 843 } 844 #ifdef SMP 845 netmsg_init(&msg.netmsg, &curthread->td_msgport, 0, 846 arp_update_msghandler); 847 msg.m = m; 848 msg.saddr = isaddr.s_addr; 849 msg.create = (itaddr.s_addr == myaddr.s_addr); 850 lwkt_domsg(rtable_portfn(0), &msg.netmsg.nm_lmsg, 0); 851 #else 852 arp_update_oncpu(m, isaddr.s_addr, (itaddr.s_addr == myaddr.s_addr), 853 TRUE); 854 #endif 855 reply: 856 if (op != ARPOP_REQUEST) { 857 m_freem(m); 858 return; 859 } 860 if (itaddr.s_addr == myaddr.s_addr) { 861 /* I am the target */ 862 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 863 memcpy(ar_sha(ah), enaddr, ah->ar_hln); 864 } else { 865 struct llinfo_arp *la; 866 867 la = arplookup(itaddr.s_addr, FALSE, SIN_PROXY); 868 if (la == NULL) { 869 struct sockaddr_in sin; 870 871 if (!arp_proxyall) { 872 m_freem(m); 873 return; 874 } 875 876 bzero(&sin, sizeof sin); 877 sin.sin_family = AF_INET; 878 sin.sin_len = sizeof sin; 879 sin.sin_addr = itaddr; 880 881 rt = rtpurelookup((struct sockaddr *)&sin); 882 if (rt == NULL) { 883 m_freem(m); 884 return; 885 } 886 --rt->rt_refcnt; 887 /* 888 * Don't send proxies for nodes on the same interface 889 * as this one came out of, or we'll get into a fight 890 * over who claims what Ether address. 891 */ 892 if (rt->rt_ifp == ifp) { 893 m_freem(m); 894 return; 895 } 896 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 897 memcpy(ar_sha(ah), enaddr, ah->ar_hln); 898 #ifdef DEBUG_PROXY 899 kprintf("arp: proxying for %s\n", inet_ntoa(itaddr)); 900 #endif 901 } else { 902 struct sockaddr_dl *sdl; 903 904 rt = la->la_rt; 905 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 906 sdl = SDL(rt->rt_gateway); 907 memcpy(ar_sha(ah), LLADDR(sdl), ah->ar_hln); 908 } 909 } 910 911 memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln); 912 memcpy(ar_spa(ah), &itaddr, ah->ar_pln); 913 ah->ar_op = htons(ARPOP_REPLY); 914 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 915 switch (ifp->if_type) { 916 case IFT_ETHER: 917 /* 918 * May not be correct for types not explictly 919 * listed, but it is our best guess. 920 */ 921 default: 922 eh = (struct ether_header *)sa.sa_data; 923 memcpy(eh->ether_dhost, ar_tha(ah), sizeof eh->ether_dhost); 924 eh->ether_type = htons(ETHERTYPE_ARP); 925 break; 926 } 927 sa.sa_family = AF_UNSPEC; 928 sa.sa_len = sizeof sa; 929 ifp->if_output(ifp, m, &sa, NULL); 930 } 931 932 #ifdef SMP 933 934 static void 935 arp_update_msghandler(struct netmsg *netmsg) 936 { 937 struct netmsg_arp_update *msg = (struct netmsg_arp_update *)netmsg; 938 int nextcpu; 939 940 arp_update_oncpu(msg->m, msg->saddr, msg->create, mycpuid == 0); 941 942 nextcpu = mycpuid + 1; 943 if (nextcpu < ncpus) 944 lwkt_forwardmsg(rtable_portfn(nextcpu), &msg->netmsg.nm_lmsg); 945 else 946 lwkt_replymsg(&msg->netmsg.nm_lmsg, 0); 947 } 948 949 #endif /* SMP */ 950 951 #endif /* INET */ 952 953 /* 954 * Free an arp entry. If the arp entry is actively referenced or represents 955 * a static entry we only clear it back to an unresolved state, otherwise 956 * we destroy the entry entirely. 957 * 958 * Note that static entries are created when route add ... -interface is used 959 * to create an interface route to a (direct) destination. 960 */ 961 static void 962 arptfree(struct llinfo_arp *la) 963 { 964 struct rtentry *rt = la->la_rt; 965 struct sockaddr_dl *sdl; 966 967 if (rt == NULL) 968 panic("arptfree"); 969 sdl = SDL(rt->rt_gateway); 970 if (sdl != NULL && 971 ((rt->rt_refcnt > 0 && sdl->sdl_family == AF_LINK) || 972 (rt->rt_flags & RTF_STATIC))) { 973 sdl->sdl_alen = 0; 974 la->la_preempt = la->la_asked = 0; 975 rt->rt_flags &= ~RTF_REJECT; 976 return; 977 } 978 rtrequest(RTM_DELETE, rt_key(rt), NULL, rt_mask(rt), 0, NULL); 979 } 980 981 /* 982 * Lookup or enter a new address in arptab. 983 */ 984 static struct llinfo_arp * 985 arplookup(in_addr_t addr, boolean_t create, boolean_t proxy) 986 { 987 struct rtentry *rt; 988 struct sockaddr_inarp sin = { sizeof sin, AF_INET }; 989 const char *why = NULL; 990 991 sin.sin_addr.s_addr = addr; 992 sin.sin_other = proxy ? SIN_PROXY : 0; 993 if (create) 994 rt = rtlookup((struct sockaddr *)&sin); 995 else 996 rt = rtpurelookup((struct sockaddr *)&sin); 997 if (rt == NULL) 998 return (NULL); 999 rt->rt_refcnt--; 1000 1001 if (rt->rt_flags & RTF_GATEWAY) 1002 why = "host is not on local network"; 1003 else if (!(rt->rt_flags & RTF_LLINFO)) 1004 why = "could not allocate llinfo"; 1005 else if (rt->rt_gateway->sa_family != AF_LINK) 1006 why = "gateway route is not ours"; 1007 1008 if (why) { 1009 if (create) { 1010 log(LOG_DEBUG, "arplookup %s failed: %s\n", 1011 inet_ntoa(sin.sin_addr), why); 1012 } 1013 if (rt->rt_refcnt <= 0 && (rt->rt_flags & RTF_WASCLONED)) { 1014 /* No references to this route. Purge it. */ 1015 rtrequest(RTM_DELETE, rt_key(rt), rt->rt_gateway, 1016 rt_mask(rt), rt->rt_flags, NULL); 1017 } 1018 return (NULL); 1019 } 1020 return (rt->rt_llinfo); 1021 } 1022 1023 void 1024 arp_ifinit(struct ifnet *ifp, struct ifaddr *ifa) 1025 { 1026 if (IA_SIN(ifa)->sin_addr.s_addr != INADDR_ANY) { 1027 arprequest_async(ifp, &IA_SIN(ifa)->sin_addr, 1028 &IA_SIN(ifa)->sin_addr, IF_LLADDR(ifp)); 1029 } 1030 ifa->ifa_rtrequest = arp_rtrequest; 1031 ifa->ifa_flags |= RTF_CLONING; 1032 } 1033 1034 void 1035 arp_ifinit2(struct ifnet *ifp, struct ifaddr *ifa, u_char *enaddr) 1036 { 1037 if (IA_SIN(ifa)->sin_addr.s_addr != INADDR_ANY) { 1038 arprequest_async(ifp, &IA_SIN(ifa)->sin_addr, 1039 &IA_SIN(ifa)->sin_addr, enaddr); 1040 } 1041 ifa->ifa_rtrequest = arp_rtrequest; 1042 ifa->ifa_flags |= RTF_CLONING; 1043 } 1044 1045 static void 1046 arp_init(void) 1047 { 1048 uint32_t flags; 1049 int cpu; 1050 1051 for (cpu = 0; cpu < ncpus2; cpu++) 1052 LIST_INIT(&llinfo_arp_list[cpu]); 1053 1054 if (arp_mpsafe) { 1055 flags = NETISR_FLAG_MPSAFE; 1056 kprintf("arp: MPSAFE\n"); 1057 } else { 1058 flags = NETISR_FLAG_NOTMPSAFE; 1059 } 1060 netisr_register(NETISR_ARP, cpu0_portfn, arpintr, flags); 1061 } 1062 1063 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0); 1064