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sys/netinet/if_ether.c
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1 /* 2 * Copyright (c) 1982, 1986, 1988, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#)if_ether.c 8.1 (Berkeley) 6/10/93 34 * $FreeBSD: releng/5.2/sys/netinet/if_ether.c 122334 2003-11-08 23:36:32Z sam $ 35 */ 36 37 /* 38 * Ethernet address resolution protocol. 39 * TODO: 40 * add "inuse/lock" bit (or ref. count) along with valid bit 41 */ 42 43 #include "opt_inet.h" 44 #include "opt_bdg.h" 45 #include "opt_mac.h" 46 47 #include <sys/param.h> 48 #include <sys/kernel.h> 49 #include <sys/queue.h> 50 #include <sys/sysctl.h> 51 #include <sys/systm.h> 52 #include <sys/mac.h> 53 #include <sys/mbuf.h> 54 #include <sys/malloc.h> 55 #include <sys/socket.h> 56 #include <sys/syslog.h> 57 58 #include <net/if.h> 59 #include <net/if_dl.h> 60 #include <net/if_types.h> 61 #include <net/route.h> 62 #include <net/netisr.h> 63 #include <net/if_llc.h> 64 #ifdef BRIDGE 65 #include <net/ethernet.h> 66 #include <net/bridge.h> 67 #endif 68 69 #include <netinet/in.h> 70 #include <netinet/in_var.h> 71 #include <netinet/if_ether.h> 72 73 #include <net/if_arc.h> 74 #include <net/iso88025.h> 75 76 #define SIN(s) ((struct sockaddr_in *)s) 77 #define SDL(s) ((struct sockaddr_dl *)s) 78 79 SYSCTL_DECL(_net_link_ether); 80 SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, ""); 81 82 /* timer values */ 83 static int arpt_prune = (5*60*1); /* walk list every 5 minutes */ 84 static int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */ 85 static int arpt_down = 20; /* once declared down, don't send for 20 sec */ 86 87 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, prune_intvl, CTLFLAG_RW, 88 &arpt_prune, 0, ""); 89 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW, 90 &arpt_keep, 0, ""); 91 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, host_down_time, CTLFLAG_RW, 92 &arpt_down, 0, ""); 93 94 #define rt_expire rt_rmx.rmx_expire 95 96 struct llinfo_arp { 97 LIST_ENTRY(llinfo_arp) la_le; 98 struct rtentry *la_rt; 99 struct mbuf *la_hold; /* last packet until resolved/timeout */ 100 u_short la_preempt; /* countdown for pre-expiry arps */ 101 u_short la_asked; /* #times we QUERIED following expiration */ 102 #define la_timer la_rt->rt_rmx.rmx_expire /* deletion time in seconds */ 103 }; 104 105 static LIST_HEAD(, llinfo_arp) llinfo_arp; 106 107 static struct ifqueue arpintrq; 108 static int arp_allocated; 109 static int arpinit_done; 110 111 static int arp_maxtries = 5; 112 static int useloopback = 1; /* use loopback interface for local traffic */ 113 static int arp_proxyall = 0; 114 static struct callout arp_callout; 115 116 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW, 117 &arp_maxtries, 0, ""); 118 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW, 119 &useloopback, 0, ""); 120 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW, 121 &arp_proxyall, 0, ""); 122 123 static void arp_init(void); 124 static void arp_rtrequest(int, struct rtentry *, struct rt_addrinfo *); 125 static void arprequest(struct ifnet *, 126 struct in_addr *, struct in_addr *, u_char *); 127 static void arpintr(struct mbuf *); 128 static void arptfree(struct llinfo_arp *); 129 static void arptimer(void *); 130 static struct llinfo_arp 131 *arplookup(u_long, int, int); 132 #ifdef INET 133 static void in_arpinput(struct mbuf *); 134 #endif 135 136 /* 137 * Timeout routine. Age arp_tab entries periodically. 138 */ 139 /* ARGSUSED */ 140 static void 141 arptimer(ignored_arg) 142 void *ignored_arg; 143 { 144 struct llinfo_arp *la, *ola; 145 146 RADIX_NODE_HEAD_LOCK(rt_tables[AF_INET]); 147 la = LIST_FIRST(&llinfo_arp); 148 while (la != NULL) { 149 struct rtentry *rt = la->la_rt; 150 ola = la; 151 la = LIST_NEXT(la, la_le); 152 if (rt->rt_expire && rt->rt_expire <= time_second) 153 arptfree(ola); /* timer has expired, clear */ 154 } 155 RADIX_NODE_HEAD_UNLOCK(rt_tables[AF_INET]); 156 157 callout_reset(&arp_callout, arpt_prune * hz, arptimer, NULL); 158 } 159 160 /* 161 * Parallel to llc_rtrequest. 162 */ 163 static void 164 arp_rtrequest(req, rt, info) 165 int req; 166 register struct rtentry *rt; 167 struct rt_addrinfo *info; 168 { 169 register struct sockaddr *gate; 170 register struct llinfo_arp *la; 171 static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK}; 172 173 RT_LOCK_ASSERT(rt); 174 175 if (!arpinit_done) { 176 arpinit_done = 1; 177 callout_reset(&arp_callout, hz, arptimer, NULL); 178 } 179 if (rt->rt_flags & RTF_GATEWAY) 180 return; 181 gate = rt->rt_gateway; 182 la = (struct llinfo_arp *)rt->rt_llinfo; 183 switch (req) { 184 185 case RTM_ADD: 186 /* 187 * XXX: If this is a manually added route to interface 188 * such as older version of routed or gated might provide, 189 * restore cloning bit. 190 */ 191 if ((rt->rt_flags & RTF_HOST) == 0 && 192 SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff) 193 rt->rt_flags |= RTF_CLONING; 194 if (rt->rt_flags & RTF_CLONING) { 195 /* 196 * Case 1: This route should come from a route to iface. 197 */ 198 rt_setgate(rt, rt_key(rt), 199 (struct sockaddr *)&null_sdl); 200 gate = rt->rt_gateway; 201 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 202 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 203 rt->rt_expire = time_second; 204 break; 205 } 206 /* Announce a new entry if requested. */ 207 if (rt->rt_flags & RTF_ANNOUNCE) 208 arprequest(rt->rt_ifp, 209 &SIN(rt_key(rt))->sin_addr, 210 &SIN(rt_key(rt))->sin_addr, 211 (u_char *)LLADDR(SDL(gate))); 212 /*FALLTHROUGH*/ 213 case RTM_RESOLVE: 214 if (gate->sa_family != AF_LINK || 215 gate->sa_len < sizeof(null_sdl)) { 216 log(LOG_DEBUG, "%s: bad gateway %s%s\n", __func__, 217 inet_ntoa(SIN(rt_key(rt))->sin_addr), 218 (gate->sa_family != AF_LINK) ? 219 " (!AF_LINK)": ""); 220 break; 221 } 222 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 223 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 224 if (la != 0) 225 break; /* This happens on a route change */ 226 /* 227 * Case 2: This route may come from cloning, or a manual route 228 * add with a LL address. 229 */ 230 R_Zalloc(la, struct llinfo_arp *, sizeof(*la)); 231 rt->rt_llinfo = (caddr_t)la; 232 if (la == 0) { 233 log(LOG_DEBUG, "%s: malloc failed\n", __func__); 234 break; 235 } 236 arp_allocated++; 237 la->la_rt = rt; 238 rt->rt_flags |= RTF_LLINFO; 239 RADIX_NODE_HEAD_LOCK_ASSERT(rt_tables[AF_INET]); 240 LIST_INSERT_HEAD(&llinfo_arp, la, la_le); 241 242 #ifdef INET 243 /* 244 * This keeps the multicast addresses from showing up 245 * in `arp -a' listings as unresolved. It's not actually 246 * functional. Then the same for broadcast. 247 */ 248 if (IN_MULTICAST(ntohl(SIN(rt_key(rt))->sin_addr.s_addr)) && 249 rt->rt_ifp->if_type != IFT_ARCNET) { 250 ETHER_MAP_IP_MULTICAST(&SIN(rt_key(rt))->sin_addr, 251 LLADDR(SDL(gate))); 252 SDL(gate)->sdl_alen = 6; 253 rt->rt_expire = 0; 254 } 255 if (in_broadcast(SIN(rt_key(rt))->sin_addr, rt->rt_ifp)) { 256 memcpy(LLADDR(SDL(gate)), rt->rt_ifp->if_broadcastaddr, 257 rt->rt_ifp->if_addrlen); 258 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen; 259 rt->rt_expire = 0; 260 } 261 #endif 262 263 if (SIN(rt_key(rt))->sin_addr.s_addr == 264 (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) { 265 /* 266 * This test used to be 267 * if (loif.if_flags & IFF_UP) 268 * It allowed local traffic to be forced 269 * through the hardware by configuring the loopback down. 270 * However, it causes problems during network configuration 271 * for boards that can't receive packets they send. 272 * It is now necessary to clear "useloopback" and remove 273 * the route to force traffic out to the hardware. 274 */ 275 rt->rt_expire = 0; 276 Bcopy(IF_LLADDR(rt->rt_ifp), LLADDR(SDL(gate)), 277 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen); 278 if (useloopback) 279 rt->rt_ifp = loif; 280 281 } 282 break; 283 284 case RTM_DELETE: 285 if (la == 0) 286 break; 287 RADIX_NODE_HEAD_LOCK_ASSERT(rt_tables[AF_INET]); 288 LIST_REMOVE(la, la_le); 289 rt->rt_llinfo = 0; 290 rt->rt_flags &= ~RTF_LLINFO; 291 if (la->la_hold) 292 m_freem(la->la_hold); 293 Free((caddr_t)la); 294 } 295 } 296 297 /* 298 * Broadcast an ARP request. Caller specifies: 299 * - arp header source ip address 300 * - arp header target ip address 301 * - arp header source ethernet address 302 */ 303 static void 304 arprequest(ifp, sip, tip, enaddr) 305 register struct ifnet *ifp; 306 register struct in_addr *sip, *tip; 307 register u_char *enaddr; 308 { 309 register struct mbuf *m; 310 register struct ether_header *eh; 311 register struct arc_header *arh; 312 register struct arphdr *ah; 313 struct sockaddr sa; 314 static u_char llcx[] = { 0x82, 0x40, LLC_SNAP_LSAP, LLC_SNAP_LSAP, 315 LLC_UI, 0x00, 0x00, 0x00, 0x08, 0x06 }; 316 u_short ar_hrd; 317 318 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 319 return; 320 m->m_pkthdr.rcvif = (struct ifnet *)0; 321 #ifdef MAC 322 mac_create_mbuf_linklayer(ifp, m); 323 #endif 324 switch (ifp->if_type) { 325 case IFT_ARCNET: 326 ar_hrd = htons(ARPHRD_ARCNET); 327 328 m->m_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 329 m->m_pkthdr.len = m->m_len; 330 MH_ALIGN(m, m->m_len); 331 332 arh = (struct arc_header *)sa.sa_data; 333 arh->arc_dhost = *ifp->if_broadcastaddr; 334 arh->arc_type = ARCTYPE_ARP; 335 336 ah = mtod(m, struct arphdr *); 337 break; 338 339 case IFT_ISO88025: 340 ar_hrd = htons(ARPHRD_IEEE802); 341 342 m->m_len = sizeof(llcx) + 343 arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 344 m->m_pkthdr.len = m->m_len; 345 MH_ALIGN(m, m->m_len); 346 347 (void)memcpy(mtod(m, caddr_t), llcx, sizeof(llcx)); 348 (void)memcpy(sa.sa_data, ifp->if_broadcastaddr, 6); 349 (void)memcpy(sa.sa_data + 6, enaddr, 6); 350 sa.sa_data[6] |= TR_RII; 351 sa.sa_data[12] = TR_AC; 352 sa.sa_data[13] = TR_LLC_FRAME; 353 354 ah = (struct arphdr *)(mtod(m, char *) + sizeof(llcx)); 355 break; 356 case IFT_FDDI: 357 case IFT_ETHER: 358 /* 359 * This may not be correct for types not explicitly 360 * listed, but this is our best guess 361 */ 362 default: 363 ar_hrd = htons(ARPHRD_ETHER); 364 365 m->m_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 366 m->m_pkthdr.len = m->m_len; 367 MH_ALIGN(m, m->m_len); 368 369 eh = (struct ether_header *)sa.sa_data; 370 /* if_output will not swap */ 371 eh->ether_type = htons(ETHERTYPE_ARP); 372 (void)memcpy(eh->ether_dhost, ifp->if_broadcastaddr, 373 sizeof(eh->ether_dhost)); 374 375 ah = mtod(m, struct arphdr *); 376 break; 377 } 378 379 ah->ar_hrd = ar_hrd; 380 ah->ar_pro = htons(ETHERTYPE_IP); 381 ah->ar_hln = ifp->if_addrlen; /* hardware address length */ 382 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 383 ah->ar_op = htons(ARPOP_REQUEST); 384 (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln); 385 memset(ar_tha(ah), 0, ah->ar_hln); 386 (void)memcpy(ar_spa(ah), sip, ah->ar_pln); 387 (void)memcpy(ar_tpa(ah), tip, ah->ar_pln); 388 389 sa.sa_family = AF_UNSPEC; 390 sa.sa_len = sizeof(sa); 391 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 392 } 393 394 /* 395 * Resolve an IP address into an ethernet address. If success, 396 * desten is filled in. If there is no entry in arptab, 397 * set one up and broadcast a request for the IP address. 398 * Hold onto this mbuf and resend it once the address 399 * is finally resolved. A return value of 1 indicates 400 * that desten has been filled in and the packet should be sent 401 * normally; a 0 return indicates that the packet has been 402 * taken over here, either now or for later transmission. 403 */ 404 int 405 arpresolve(ifp, rt, m, dst, desten, rt0) 406 register struct ifnet *ifp; 407 register struct rtentry *rt; 408 struct mbuf *m; 409 register struct sockaddr *dst; 410 register u_char *desten; 411 struct rtentry *rt0; 412 { 413 struct llinfo_arp *la = 0; 414 struct sockaddr_dl *sdl; 415 416 if (m->m_flags & M_BCAST) { /* broadcast */ 417 (void)memcpy(desten, ifp->if_broadcastaddr, ifp->if_addrlen); 418 return (1); 419 } 420 if (m->m_flags & M_MCAST && ifp->if_type != IFT_ARCNET) {/* multicast */ 421 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); 422 return(1); 423 } 424 if (rt) 425 la = (struct llinfo_arp *)rt->rt_llinfo; 426 if (la == 0) { 427 la = arplookup(SIN(dst)->sin_addr.s_addr, 1, 0); 428 if (la) 429 rt = la->la_rt; 430 } 431 if (la == 0 || rt == 0) { 432 log(LOG_DEBUG, "arpresolve: can't allocate llinfo for %s%s%s\n", 433 inet_ntoa(SIN(dst)->sin_addr), la ? "la" : "", 434 rt ? "rt" : ""); 435 m_freem(m); 436 return (0); 437 } 438 sdl = SDL(rt->rt_gateway); 439 /* 440 * Check the address family and length is valid, the address 441 * is resolved; otherwise, try to resolve. 442 */ 443 if ((rt->rt_expire == 0 || rt->rt_expire > time_second) && 444 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 445 /* 446 * If entry has an expiry time and it is approaching, 447 * see if we need to send an ARP request within this 448 * arpt_down interval. 449 */ 450 if ((rt->rt_expire != 0) && 451 (time_second + la->la_preempt > rt->rt_expire)) { 452 arprequest(ifp, 453 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 454 &SIN(dst)->sin_addr, 455 IF_LLADDR(ifp)); 456 la->la_preempt--; 457 } 458 459 bcopy(LLADDR(sdl), desten, sdl->sdl_alen); 460 return 1; 461 } 462 /* 463 * If ARP is disabled or static on this interface, stop. 464 * XXX 465 * Probably should not allocate empty llinfo struct if we are 466 * not going to be sending out an arp request. 467 */ 468 if (ifp->if_flags & (IFF_NOARP | IFF_STATICARP)) { 469 m_freem(m); 470 return (0); 471 } 472 /* 473 * There is an arptab entry, but no ethernet address 474 * response yet. Replace the held mbuf with this 475 * latest one. 476 */ 477 if (la->la_hold) 478 m_freem(la->la_hold); 479 la->la_hold = m; 480 if (rt->rt_expire) { 481 RT_LOCK(rt); 482 rt->rt_flags &= ~RTF_REJECT; 483 if (la->la_asked == 0 || rt->rt_expire != time_second) { 484 rt->rt_expire = time_second; 485 if (la->la_asked++ < arp_maxtries) { 486 arprequest(ifp, 487 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 488 &SIN(dst)->sin_addr, 489 IF_LLADDR(ifp)); 490 } else { 491 rt->rt_flags |= RTF_REJECT; 492 rt->rt_expire += arpt_down; 493 la->la_asked = 0; 494 la->la_preempt = arp_maxtries; 495 } 496 497 } 498 RT_UNLOCK(rt); 499 } 500 return (0); 501 } 502 503 /* 504 * Common length and type checks are done here, 505 * then the protocol-specific routine is called. 506 */ 507 static void 508 arpintr(struct mbuf *m) 509 { 510 struct arphdr *ar; 511 512 if (!arpinit_done) { 513 /* NB: this race should not matter */ 514 arpinit_done = 1; 515 callout_reset(&arp_callout, hz, arptimer, NULL); 516 } 517 if (m->m_len < sizeof(struct arphdr) && 518 ((m = m_pullup(m, sizeof(struct arphdr))) == NULL)) { 519 log(LOG_ERR, "arp: runt packet -- m_pullup failed\n"); 520 return; 521 } 522 ar = mtod(m, struct arphdr *); 523 524 if (ntohs(ar->ar_hrd) != ARPHRD_ETHER && 525 ntohs(ar->ar_hrd) != ARPHRD_IEEE802 && 526 ntohs(ar->ar_hrd) != ARPHRD_ARCNET) { 527 log(LOG_ERR, "arp: unknown hardware address format (0x%2D)\n", 528 (unsigned char *)&ar->ar_hrd, ""); 529 m_freem(m); 530 return; 531 } 532 533 if (m->m_pkthdr.len < arphdr_len(ar) && 534 (m = m_pullup(m, arphdr_len(ar))) == NULL) { 535 log(LOG_ERR, "arp: runt packet\n"); 536 m_freem(m); 537 return; 538 } 539 540 switch (ntohs(ar->ar_pro)) { 541 #ifdef INET 542 case ETHERTYPE_IP: 543 in_arpinput(m); 544 return; 545 #endif 546 } 547 m_freem(m); 548 } 549 550 #ifdef INET 551 /* 552 * ARP for Internet protocols on 10 Mb/s Ethernet. 553 * Algorithm is that given in RFC 826. 554 * In addition, a sanity check is performed on the sender 555 * protocol address, to catch impersonators. 556 * We no longer handle negotiations for use of trailer protocol: 557 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 558 * along with IP replies if we wanted trailers sent to us, 559 * and also sent them in response to IP replies. 560 * This allowed either end to announce the desire to receive 561 * trailer packets. 562 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 563 * but formerly didn't normally send requests. 564 */ 565 static int log_arp_wrong_iface = 1; 566 static int log_arp_movements = 1; 567 568 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW, 569 &log_arp_wrong_iface, 0, 570 "log arp packets arriving on the wrong interface"); 571 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_movements, CTLFLAG_RW, 572 &log_arp_movements, 0, 573 "log arp replies from MACs different than the one in the cache"); 574 575 576 static void 577 in_arpinput(m) 578 struct mbuf *m; 579 { 580 register struct arphdr *ah; 581 register struct ifnet *ifp = m->m_pkthdr.rcvif; 582 struct ether_header *eh; 583 struct arc_header *arh; 584 struct iso88025_header *th = (struct iso88025_header *)0; 585 struct iso88025_sockaddr_dl_data *trld; 586 register struct llinfo_arp *la = 0; 587 register struct rtentry *rt; 588 struct ifaddr *ifa; 589 struct in_ifaddr *ia; 590 struct sockaddr_dl *sdl; 591 struct sockaddr sa; 592 struct in_addr isaddr, itaddr, myaddr; 593 int op, rif_len; 594 int req_len; 595 596 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 597 if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) { 598 log(LOG_ERR, "in_arp: runt packet -- m_pullup failed\n"); 599 return; 600 } 601 602 ah = mtod(m, struct arphdr *); 603 op = ntohs(ah->ar_op); 604 (void)memcpy(&isaddr, ar_spa(ah), sizeof (isaddr)); 605 (void)memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr)); 606 #ifdef BRIDGE 607 #define BRIDGE_TEST (do_bridge) 608 #else 609 #define BRIDGE_TEST (0) /* cc will optimise the test away */ 610 #endif 611 /* 612 * For a bridge, we want to check the address irrespective 613 * of the receive interface. (This will change slightly 614 * when we have clusters of interfaces). 615 */ 616 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) 617 if ((BRIDGE_TEST || (ia->ia_ifp == ifp)) && 618 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) 619 goto match; 620 LIST_FOREACH(ia, INADDR_HASH(isaddr.s_addr), ia_hash) 621 if ((BRIDGE_TEST || (ia->ia_ifp == ifp)) && 622 isaddr.s_addr == ia->ia_addr.sin_addr.s_addr) 623 goto match; 624 /* 625 * No match, use the first inet address on the receive interface 626 * as a dummy address for the rest of the function. 627 */ 628 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) 629 if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_INET) { 630 ia = ifatoia(ifa); 631 goto match; 632 } 633 /* 634 * If bridging, fall back to using any inet address. 635 */ 636 if (!BRIDGE_TEST || 637 (ia = TAILQ_FIRST(&in_ifaddrhead)) == NULL) { 638 m_freem(m); 639 return; 640 } 641 match: 642 myaddr = ia->ia_addr.sin_addr; 643 if (!bcmp(ar_sha(ah), IF_LLADDR(ifp), ifp->if_addrlen)) { 644 m_freem(m); /* it's from me, ignore it. */ 645 return; 646 } 647 if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) { 648 log(LOG_ERR, 649 "arp: link address is broadcast for IP address %s!\n", 650 inet_ntoa(isaddr)); 651 m_freem(m); 652 return; 653 } 654 if (isaddr.s_addr == myaddr.s_addr) { 655 log(LOG_ERR, 656 "arp: %*D is using my IP address %s!\n", 657 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 658 inet_ntoa(isaddr)); 659 itaddr = myaddr; 660 goto reply; 661 } 662 if (ifp->if_flags & IFF_STATICARP) 663 goto reply; 664 la = arplookup(isaddr.s_addr, itaddr.s_addr == myaddr.s_addr, 0); 665 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { 666 /* the following is not an error when doing bridging */ 667 if (!BRIDGE_TEST && rt->rt_ifp != ifp) { 668 if (log_arp_wrong_iface) 669 log(LOG_ERR, "arp: %s is on %s but got reply from %*D on %s\n", 670 inet_ntoa(isaddr), 671 rt->rt_ifp->if_xname, 672 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 673 ifp->if_xname); 674 goto reply; 675 } 676 if (sdl->sdl_alen && 677 bcmp(ar_sha(ah), LLADDR(sdl), sdl->sdl_alen)) { 678 if (rt->rt_expire) { 679 if (log_arp_movements) 680 log(LOG_INFO, "arp: %s moved from %*D to %*D on %s\n", 681 inet_ntoa(isaddr), 682 ifp->if_addrlen, (u_char *)LLADDR(sdl), ":", 683 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 684 ifp->if_xname); 685 } else { 686 log(LOG_ERR, 687 "arp: %*D attempts to modify permanent entry for %s on %s\n", 688 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 689 inet_ntoa(isaddr), ifp->if_xname); 690 goto reply; 691 } 692 } 693 /* 694 * sanity check for the address length. 695 * XXX this does not work for protocols with variable address 696 * length. -is 697 */ 698 if (sdl->sdl_alen && 699 sdl->sdl_alen != ah->ar_hln) { 700 log(LOG_WARNING, 701 "arp from %*D: new addr len %d, was %d", 702 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 703 ah->ar_hln, sdl->sdl_alen); 704 } 705 if (ifp->if_addrlen != ah->ar_hln) { 706 log(LOG_WARNING, 707 "arp from %*D: addr len: new %d, i/f %d (ignored)", 708 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 709 ah->ar_hln, ifp->if_addrlen); 710 goto reply; 711 } 712 (void)memcpy(LLADDR(sdl), ar_sha(ah), 713 sdl->sdl_alen = ah->ar_hln); 714 /* 715 * If we receive an arp from a token-ring station over 716 * a token-ring nic then try to save the source 717 * routing info. 718 */ 719 if (ifp->if_type == IFT_ISO88025) { 720 th = (struct iso88025_header *)m->m_pkthdr.header; 721 trld = SDL_ISO88025(sdl); 722 rif_len = TR_RCF_RIFLEN(th->rcf); 723 if ((th->iso88025_shost[0] & TR_RII) && 724 (rif_len > 2)) { 725 trld->trld_rcf = th->rcf; 726 trld->trld_rcf ^= htons(TR_RCF_DIR); 727 memcpy(trld->trld_route, th->rd, rif_len - 2); 728 trld->trld_rcf &= ~htons(TR_RCF_BCST_MASK); 729 /* 730 * Set up source routing information for 731 * reply packet (XXX) 732 */ 733 m->m_data -= rif_len; 734 m->m_len += rif_len; 735 m->m_pkthdr.len += rif_len; 736 } else { 737 th->iso88025_shost[0] &= ~TR_RII; 738 trld->trld_rcf = 0; 739 } 740 m->m_data -= 8; 741 m->m_len += 8; 742 m->m_pkthdr.len += 8; 743 th->rcf = trld->trld_rcf; 744 } 745 RT_LOCK(rt); 746 if (rt->rt_expire) 747 rt->rt_expire = time_second + arpt_keep; 748 rt->rt_flags &= ~RTF_REJECT; 749 RT_UNLOCK(rt); 750 la->la_asked = 0; 751 la->la_preempt = arp_maxtries; 752 if (la->la_hold) { 753 (*ifp->if_output)(ifp, la->la_hold, 754 rt_key(rt), rt); 755 la->la_hold = 0; 756 } 757 } 758 reply: 759 if (op != ARPOP_REQUEST) { 760 m_freem(m); 761 return; 762 } 763 if (itaddr.s_addr == myaddr.s_addr) { 764 /* I am the target */ 765 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 766 (void)memcpy(ar_sha(ah), IF_LLADDR(ifp), ah->ar_hln); 767 } else { 768 la = arplookup(itaddr.s_addr, 0, SIN_PROXY); 769 if (la == NULL) { 770 struct sockaddr_in sin; 771 772 if (!arp_proxyall) { 773 m_freem(m); 774 return; 775 } 776 777 bzero(&sin, sizeof sin); 778 sin.sin_family = AF_INET; 779 sin.sin_len = sizeof sin; 780 sin.sin_addr = itaddr; 781 782 rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL); 783 if (!rt) { 784 m_freem(m); 785 return; 786 } 787 /* 788 * Don't send proxies for nodes on the same interface 789 * as this one came out of, or we'll get into a fight 790 * over who claims what Ether address. 791 */ 792 if (rt->rt_ifp == ifp) { 793 rtfree(rt); 794 m_freem(m); 795 return; 796 } 797 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 798 (void)memcpy(ar_sha(ah), IF_LLADDR(ifp), ah->ar_hln); 799 rtfree(rt); 800 801 /* 802 * Also check that the node which sent the ARP packet 803 * is on the the interface we expect it to be on. This 804 * avoids ARP chaos if an interface is connected to the 805 * wrong network. 806 */ 807 sin.sin_addr = isaddr; 808 809 rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL); 810 if (!rt) { 811 m_freem(m); 812 return; 813 } 814 if (rt->rt_ifp != ifp) { 815 log(LOG_INFO, "arp_proxy: ignoring request" 816 " from %s via %s, expecting %s\n", 817 inet_ntoa(isaddr), ifp->if_xname, 818 rt->rt_ifp->if_xname); 819 rtfree(rt); 820 m_freem(m); 821 return; 822 } 823 rtfree(rt); 824 825 #ifdef DEBUG_PROXY 826 printf("arp: proxying for %s\n", 827 inet_ntoa(itaddr)); 828 #endif 829 } else { 830 rt = la->la_rt; 831 (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 832 sdl = SDL(rt->rt_gateway); 833 (void)memcpy(ar_sha(ah), LLADDR(sdl), ah->ar_hln); 834 } 835 } 836 837 (void)memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln); 838 (void)memcpy(ar_spa(ah), &itaddr, ah->ar_pln); 839 ah->ar_op = htons(ARPOP_REPLY); 840 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 841 switch (ifp->if_type) { 842 case IFT_ARCNET: 843 arh = (struct arc_header *)sa.sa_data; 844 arh->arc_dhost = *ar_tha(ah); 845 arh->arc_type = ARCTYPE_ARP; 846 break; 847 848 case IFT_ISO88025: 849 /* Re-arrange the source/dest address */ 850 memcpy(th->iso88025_dhost, th->iso88025_shost, 851 sizeof(th->iso88025_dhost)); 852 memcpy(th->iso88025_shost, IF_LLADDR(ifp), 853 sizeof(th->iso88025_shost)); 854 /* Set the source routing bit if neccesary */ 855 if (th->iso88025_dhost[0] & TR_RII) { 856 th->iso88025_dhost[0] &= ~TR_RII; 857 if (TR_RCF_RIFLEN(th->rcf) > 2) 858 th->iso88025_shost[0] |= TR_RII; 859 } 860 /* Copy the addresses, ac and fc into sa_data */ 861 memcpy(sa.sa_data, th->iso88025_dhost, 862 sizeof(th->iso88025_dhost) * 2); 863 sa.sa_data[(sizeof(th->iso88025_dhost) * 2)] = TR_AC; 864 sa.sa_data[(sizeof(th->iso88025_dhost) * 2) + 1] = TR_LLC_FRAME; 865 break; 866 case IFT_ETHER: 867 case IFT_FDDI: 868 /* 869 * May not be correct for types not explictly 870 * listed, but it is our best guess. 871 */ 872 default: 873 eh = (struct ether_header *)sa.sa_data; 874 (void)memcpy(eh->ether_dhost, ar_tha(ah), 875 sizeof(eh->ether_dhost)); 876 eh->ether_type = htons(ETHERTYPE_ARP); 877 break; 878 } 879 sa.sa_family = AF_UNSPEC; 880 sa.sa_len = sizeof(sa); 881 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 882 return; 883 } 884 #endif 885 886 /* 887 * Free an arp entry. 888 */ 889 static void 890 arptfree(la) 891 register struct llinfo_arp *la; 892 { 893 register struct rtentry *rt = la->la_rt; 894 register struct sockaddr_dl *sdl; 895 896 if (rt == 0) 897 panic("arptfree"); 898 if (rt->rt_refcnt > 0 && (sdl = SDL(rt->rt_gateway)) && 899 sdl->sdl_family == AF_LINK) { 900 sdl->sdl_alen = 0; 901 la->la_preempt = la->la_asked = 0; 902 RT_LOCK(rt); /* XXX needed or move higher? */ 903 rt->rt_flags &= ~RTF_REJECT; 904 RT_UNLOCK(rt); 905 return; 906 } 907 rtrequest(RTM_DELETE, rt_key(rt), (struct sockaddr *)0, rt_mask(rt), 908 0, (struct rtentry **)0); 909 } 910 /* 911 * Lookup or enter a new address in arptab. 912 */ 913 static struct llinfo_arp * 914 arplookup(addr, create, proxy) 915 u_long addr; 916 int create, proxy; 917 { 918 register struct rtentry *rt; 919 struct sockaddr_inarp sin; 920 const char *why = 0; 921 922 bzero(&sin, sizeof(sin)); 923 sin.sin_len = sizeof(sin); 924 sin.sin_family = AF_INET; 925 sin.sin_addr.s_addr = addr; 926 if (proxy) 927 sin.sin_other = SIN_PROXY; 928 rt = rtalloc1((struct sockaddr *)&sin, create, 0UL); 929 if (rt == 0) 930 return (0); 931 932 if (rt->rt_flags & RTF_GATEWAY) 933 why = "host is not on local network"; 934 else if ((rt->rt_flags & RTF_LLINFO) == 0) 935 why = "could not allocate llinfo"; 936 else if (rt->rt_gateway->sa_family != AF_LINK) 937 why = "gateway route is not ours"; 938 939 if (why) { 940 #define ISDYNCLONE(_rt) \ 941 (((_rt)->rt_flags & (RTF_STATIC | RTF_WASCLONED)) == RTF_WASCLONED) 942 if (create) 943 log(LOG_DEBUG, "arplookup %s failed: %s\n", 944 inet_ntoa(sin.sin_addr), why); 945 /* 946 * If there are no references to this Layer 2 route, 947 * and it is a cloned route, and not static, and 948 * arplookup() is creating the route, then purge 949 * it from the routing table as it is probably bogus. 950 */ 951 if (rt->rt_refcnt == 1 && ISDYNCLONE(rt)) 952 rtexpunge(rt); 953 RTFREE_LOCKED(rt); 954 return (0); 955 #undef ISDYNCLONE 956 } else { 957 RT_REMREF(rt); 958 RT_UNLOCK(rt); 959 return ((struct llinfo_arp *)rt->rt_llinfo); 960 } 961 } 962 963 void 964 arp_ifinit(ifp, ifa) 965 struct ifnet *ifp; 966 struct ifaddr *ifa; 967 { 968 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY) 969 arprequest(ifp, &IA_SIN(ifa)->sin_addr, 970 &IA_SIN(ifa)->sin_addr, IF_LLADDR(ifp)); 971 ifa->ifa_rtrequest = arp_rtrequest; 972 ifa->ifa_flags |= RTF_CLONING; 973 } 974 975 static void 976 arp_init(void) 977 { 978 979 arpintrq.ifq_maxlen = 50; 980 mtx_init(&arpintrq.ifq_mtx, "arp_inq", NULL, MTX_DEF); 981 LIST_INIT(&llinfo_arp); 982 callout_init(&arp_callout, CALLOUT_MPSAFE); 983 netisr_register(NETISR_ARP, arpintr, &arpintrq, NETISR_MPSAFE); 984 } 985 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0);
Cache object: 5400cc97188abcb043ad204ed4b9e5c1
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