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) 2004, 2005 Jeffrey M. Hsu. All rights reserved. 35 * 36 * License terms: all terms for the DragonFly license above plus the following: 37 * 38 * 4. All advertising materials mentioning features or use of this software 39 * must display the following acknowledgement: 40 * 41 * This product includes software developed by Jeffrey M. Hsu 42 * for the DragonFly Project. 43 * 44 * This requirement may be waived with permission from Jeffrey Hsu. 45 * Permission will be granted to any DragonFly user for free. 46 * This requirement will sunset and may be removed on Jan 31, 2006, 47 * after which the standard DragonFly license (as shown above) will 48 * apply. 49 */ 50 51 /* 52 * Copyright (c) 1982, 1986, 1988, 1993 53 * The Regents of the University of California. All rights reserved. 54 * 55 * Redistribution and use in source and binary forms, with or without 56 * modification, are permitted provided that the following conditions 57 * are met: 58 * 1. Redistributions of source code must retain the above copyright 59 * notice, this list of conditions and the following disclaimer. 60 * 2. Redistributions in binary form must reproduce the above copyright 61 * notice, this list of conditions and the following disclaimer in the 62 * documentation and/or other materials provided with the distribution. 63 * 3. All advertising materials mentioning features or use of this software 64 * must display the following acknowledgement: 65 * This product includes software developed by the University of 66 * California, Berkeley and its contributors. 67 * 4. Neither the name of the University nor the names of its contributors 68 * may be used to endorse or promote products derived from this software 69 * without specific prior written permission. 70 * 71 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 72 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 73 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 74 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 75 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 76 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 77 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 78 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 79 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 80 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 81 * SUCH DAMAGE. 82 * 83 * @(#)if_ether.c 8.1 (Berkeley) 6/10/93 84 * $FreeBSD: src/sys/netinet/if_ether.c,v 1.64.2.23 2003/04/11 07:23:15 fjoe Exp $ 85 * $DragonFly: src/sys/netinet/if_ether.c,v 1.27 2005/06/02 23:52:42 dillon Exp $ 86 */ 87 88 /* 89 * Ethernet address resolution protocol. 90 * TODO: 91 * add "inuse/lock" bit (or ref. count) along with valid bit 92 */ 93 94 #include "opt_inet.h" 95 #include "opt_bdg.h" 96 97 #include <sys/param.h> 98 #include <sys/kernel.h> 99 #include <sys/queue.h> 100 #include <sys/sysctl.h> 101 #include <sys/systm.h> 102 #include <sys/mbuf.h> 103 #include <sys/malloc.h> 104 #include <sys/socket.h> 105 #include <sys/syslog.h> 106 107 #include <sys/thread2.h> 108 #include <sys/msgport2.h> 109 110 #include <net/if.h> 111 #include <net/if_dl.h> 112 #include <net/if_types.h> 113 #include <net/route.h> 114 #include <net/netisr.h> 115 #include <net/if_llc.h> 116 #ifdef BRIDGE 117 #include <net/ethernet.h> 118 #include <net/bridge/bridge.h> 119 #endif 120 121 #include <netinet/in.h> 122 #include <netinet/in_var.h> 123 #include <netinet/if_ether.h> 124 125 #include <net/if_arc.h> 126 #include <net/iso88025.h> 127 128 #define SIN(s) ((struct sockaddr_in *)s) 129 #define SDL(s) ((struct sockaddr_dl *)s) 130 131 SYSCTL_DECL(_net_link_ether); 132 SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, ""); 133 134 /* timer values */ 135 static int arpt_prune = (5*60*1); /* walk list every 5 minutes */ 136 static int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */ 137 static int arpt_down = 20; /* once declared down, don't send for 20 sec */ 138 139 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, prune_intvl, CTLFLAG_RW, 140 &arpt_prune, 0, ""); 141 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW, 142 &arpt_keep, 0, ""); 143 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, host_down_time, CTLFLAG_RW, 144 &arpt_down, 0, ""); 145 146 #define rt_expire rt_rmx.rmx_expire 147 148 struct llinfo_arp { 149 LIST_ENTRY(llinfo_arp) la_le; 150 struct rtentry *la_rt; 151 struct mbuf *la_hold; /* last packet until resolved/timeout */ 152 u_short la_preempt; /* countdown for pre-expiry arps */ 153 u_short la_asked; /* #times we QUERIED following expiration */ 154 }; 155 156 static LIST_HEAD(, llinfo_arp) llinfo_arp; 157 158 static int arp_maxtries = 5; 159 static int useloopback = 1; /* use loopback interface for local traffic */ 160 static int arp_proxyall = 0; 161 162 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW, 163 &arp_maxtries, 0, ""); 164 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW, 165 &useloopback, 0, ""); 166 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW, 167 &arp_proxyall, 0, ""); 168 169 static void arp_rtrequest (int, struct rtentry *, struct rt_addrinfo *); 170 static void arprequest (struct ifnet *, 171 struct in_addr *, struct in_addr *, u_char *); 172 static int arpintr(struct netmsg *); 173 static void arptfree (struct llinfo_arp *); 174 static void arptimer (void *); 175 static struct llinfo_arp 176 *arplookup (in_addr_t addr, boolean_t create, boolean_t proxy); 177 #ifdef INET 178 static void in_arpinput (struct mbuf *); 179 #endif 180 181 static struct callout arptimer_ch; 182 183 /* 184 * Timeout routine. Age arp_tab entries periodically. 185 */ 186 /* ARGSUSED */ 187 static void 188 arptimer(void *ignored_arg) 189 { 190 struct llinfo_arp *la, *nla; 191 192 crit_enter(); 193 LIST_FOREACH_MUTABLE(la, &llinfo_arp, la_le, nla) { 194 if (la->la_rt->rt_expire && la->la_rt->rt_expire <= time_second) 195 arptfree(la); /* might remove la from llinfo_arp! */ 196 } 197 callout_reset(&arptimer_ch, arpt_prune * hz, arptimer, NULL); 198 crit_exit(); 199 } 200 201 /* 202 * Parallel to llc_rtrequest. 203 */ 204 static void 205 arp_rtrequest(int req, struct rtentry *rt, struct rt_addrinfo *info) 206 { 207 struct sockaddr *gate = rt->rt_gateway; 208 struct llinfo_arp *la = rt->rt_llinfo; 209 210 struct sockaddr_dl null_sdl = { sizeof null_sdl, AF_LINK }; 211 static boolean_t arpinit_done; 212 213 if (!arpinit_done) { 214 arpinit_done = TRUE; 215 callout_init(&arptimer_ch); 216 callout_reset(&arptimer_ch, hz, arptimer, NULL); 217 } 218 if (rt->rt_flags & RTF_GATEWAY) 219 return; 220 221 switch (req) { 222 case RTM_ADD: 223 /* 224 * XXX: If this is a manually added route to interface 225 * such as older version of routed or gated might provide, 226 * restore cloning bit. 227 */ 228 if (!(rt->rt_flags & RTF_HOST) && 229 SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff) 230 rt->rt_flags |= RTF_CLONING; 231 if (rt->rt_flags & RTF_CLONING) { 232 /* 233 * Case 1: This route should come from a route to iface. 234 */ 235 rt_setgate(rt, rt_key(rt), 236 (struct sockaddr *)&null_sdl); 237 gate = rt->rt_gateway; 238 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 239 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 240 rt->rt_expire = time_second; 241 break; 242 } 243 /* Announce a new entry if requested. */ 244 if (rt->rt_flags & RTF_ANNOUNCE) 245 arprequest(rt->rt_ifp, 246 &SIN(rt_key(rt))->sin_addr, 247 &SIN(rt_key(rt))->sin_addr, 248 LLADDR(SDL(gate))); 249 /*FALLTHROUGH*/ 250 case RTM_RESOLVE: 251 if (gate->sa_family != AF_LINK || 252 gate->sa_len < sizeof(struct sockaddr_dl)) { 253 log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n"); 254 break; 255 } 256 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 257 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 258 if (la != NULL) 259 break; /* This happens on a route change */ 260 /* 261 * Case 2: This route may come from cloning, or a manual route 262 * add with a LL address. 263 */ 264 R_Malloc(la, struct llinfo_arp *, sizeof *la); 265 rt->rt_llinfo = la; 266 if (la == NULL) { 267 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); 268 break; 269 } 270 bzero(la, sizeof *la); 271 la->la_rt = rt; 272 rt->rt_flags |= RTF_LLINFO; 273 LIST_INSERT_HEAD(&llinfo_arp, la, la_le); 274 275 #ifdef INET 276 /* 277 * This keeps the multicast addresses from showing up 278 * in `arp -a' listings as unresolved. It's not actually 279 * functional. Then the same for broadcast. 280 */ 281 if (IN_MULTICAST(ntohl(SIN(rt_key(rt))->sin_addr.s_addr)) && 282 rt->rt_ifp->if_type != IFT_ARCNET) { 283 ETHER_MAP_IP_MULTICAST(&SIN(rt_key(rt))->sin_addr, 284 LLADDR(SDL(gate))); 285 SDL(gate)->sdl_alen = 6; 286 rt->rt_expire = 0; 287 } 288 if (in_broadcast(SIN(rt_key(rt))->sin_addr, rt->rt_ifp)) { 289 memcpy(LLADDR(SDL(gate)), rt->rt_ifp->if_broadcastaddr, 290 rt->rt_ifp->if_addrlen); 291 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen; 292 rt->rt_expire = 0; 293 } 294 #endif 295 296 if (SIN(rt_key(rt))->sin_addr.s_addr == 297 (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) { 298 /* 299 * This test used to be 300 * if (loif.if_flags & IFF_UP) 301 * It allowed local traffic to be forced 302 * through the hardware by configuring the 303 * loopback down. However, it causes problems 304 * during network configuration for boards 305 * that can't receive packets they send. It 306 * is now necessary to clear "useloopback" and 307 * remove the route to force traffic out to 308 * the hardware. 309 */ 310 rt->rt_expire = 0; 311 bcopy(IF_LLADDR(rt->rt_ifp), LLADDR(SDL(gate)), 312 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen); 313 if (useloopback) 314 rt->rt_ifp = loif; 315 } 316 break; 317 318 case RTM_DELETE: 319 if (la == NULL) 320 break; 321 LIST_REMOVE(la, la_le); 322 rt->rt_llinfo = NULL; 323 rt->rt_flags &= ~RTF_LLINFO; 324 if (la->la_hold != NULL) 325 m_freem(la->la_hold); 326 Free(la); 327 } 328 } 329 330 /* 331 * Broadcast an ARP request. Caller specifies: 332 * - arp header source ip address 333 * - arp header target ip address 334 * - arp header source ethernet address 335 */ 336 static void 337 arprequest(struct ifnet *ifp, struct in_addr *sip, struct in_addr *tip, 338 u_char *enaddr) 339 { 340 struct mbuf *m; 341 struct ether_header *eh; 342 struct arc_header *arh; 343 struct arphdr *ah; 344 struct sockaddr sa; 345 static u_char llcx[] = { 0x82, 0x40, LLC_SNAP_LSAP, LLC_SNAP_LSAP, 346 LLC_UI, 0x00, 0x00, 0x00, 0x08, 0x06 }; 347 u_short ar_hrd; 348 349 if ((m = m_gethdr(MB_DONTWAIT, MT_DATA)) == NULL) 350 return; 351 m->m_pkthdr.rcvif = (struct ifnet *)NULL; 352 353 switch (ifp->if_type) { 354 case IFT_ARCNET: 355 ar_hrd = htons(ARPHRD_ARCNET); 356 357 m->m_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 358 m->m_pkthdr.len = m->m_len; 359 MH_ALIGN(m, m->m_len); 360 361 arh = (struct arc_header *)sa.sa_data; 362 arh->arc_dhost = ifp->if_broadcastaddr[0]; 363 arh->arc_type = ARCTYPE_ARP; 364 365 ah = mtod(m, struct arphdr *); 366 break; 367 368 case IFT_ISO88025: 369 ar_hrd = htons(ARPHRD_IEEE802); 370 371 m->m_len = (sizeof llcx) + 372 arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 373 m->m_pkthdr.len = m->m_len; 374 MH_ALIGN(m, m->m_len); 375 376 memcpy(mtod(m, caddr_t), llcx, sizeof llcx); 377 memcpy(sa.sa_data, ifp->if_broadcastaddr, ifp->if_addrlen); 378 memcpy(sa.sa_data + 6, enaddr, 6); 379 sa.sa_data[6] |= TR_RII; 380 sa.sa_data[12] = TR_AC; 381 sa.sa_data[13] = TR_LLC_FRAME; 382 383 ah = (struct arphdr *)(mtod(m, char *) + sizeof llcx); 384 break; 385 case IFT_FDDI: 386 case IFT_ETHER: 387 /* 388 * This may not be correct for types not explicitly 389 * listed, but this is our best guess 390 */ 391 default: 392 ar_hrd = htons(ARPHRD_ETHER); 393 394 m->m_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 395 m->m_pkthdr.len = m->m_len; 396 MH_ALIGN(m, m->m_len); 397 398 eh = (struct ether_header *)sa.sa_data; 399 /* if_output() will not swap */ 400 eh->ether_type = htons(ETHERTYPE_ARP); 401 memcpy(eh->ether_dhost, ifp->if_broadcastaddr, ifp->if_addrlen); 402 403 ah = mtod(m, struct arphdr *); 404 break; 405 } 406 407 ah->ar_hrd = ar_hrd; 408 ah->ar_pro = htons(ETHERTYPE_IP); 409 ah->ar_hln = ifp->if_addrlen; /* hardware address length */ 410 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 411 ah->ar_op = htons(ARPOP_REQUEST); 412 memcpy(ar_sha(ah), enaddr, ah->ar_hln); 413 memset(ar_tha(ah), 0, ah->ar_hln); 414 memcpy(ar_spa(ah), sip, ah->ar_pln); 415 memcpy(ar_tpa(ah), tip, ah->ar_pln); 416 417 sa.sa_family = AF_UNSPEC; 418 sa.sa_len = sizeof sa; 419 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)NULL); 420 } 421 422 /* 423 * Resolve an IP address into an ethernet address. If success, 424 * desten is filled in. If there is no entry in arptab, 425 * set one up and broadcast a request for the IP address. 426 * Hold onto this mbuf and resend it once the address 427 * is finally resolved. A return value of 1 indicates 428 * that desten has been filled in and the packet should be sent 429 * normally; a 0 return indicates that the packet has been 430 * taken over here, either now or for later transmission. 431 */ 432 int 433 arpresolve( 434 struct ifnet *ifp, 435 struct rtentry *rt0, 436 struct mbuf *m, 437 struct sockaddr *dst, 438 u_char *desten) 439 { 440 struct rtentry *rt; 441 struct llinfo_arp *la = NULL; 442 struct sockaddr_dl *sdl; 443 444 if (m->m_flags & M_BCAST) { /* broadcast */ 445 memcpy(desten, ifp->if_broadcastaddr, ifp->if_addrlen); 446 return (1); 447 } 448 if (m->m_flags & M_MCAST && ifp->if_type != IFT_ARCNET) {/* multicast */ 449 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); 450 return (1); 451 } 452 if (rt0 != NULL) { 453 if (rt_llroute(dst, rt0, &rt) != 0) { 454 m_freem(m); 455 return 0; 456 } 457 la = rt->rt_llinfo; 458 } 459 if (la == NULL) { 460 la = arplookup(SIN(dst)->sin_addr.s_addr, TRUE, FALSE); 461 if (la != NULL) 462 rt = la->la_rt; 463 } 464 if (la == NULL || rt == NULL) { 465 log(LOG_DEBUG, "arpresolve: can't allocate llinfo for %s%s%s\n", 466 inet_ntoa(SIN(dst)->sin_addr), la ? "la" : " ", 467 rt ? "rt" : ""); 468 m_freem(m); 469 return (0); 470 } 471 sdl = SDL(rt->rt_gateway); 472 /* 473 * Check the address family and length is valid, the address 474 * is resolved; otherwise, try to resolve. 475 */ 476 if ((rt->rt_expire == 0 || rt->rt_expire > time_second) && 477 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 478 /* 479 * If entry has an expiry time and it is approaching, 480 * see if we need to send an ARP request within this 481 * arpt_down interval. 482 */ 483 if ((rt->rt_expire != 0) && 484 (time_second + la->la_preempt > rt->rt_expire)) { 485 arprequest(ifp, 486 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 487 &SIN(dst)->sin_addr, 488 IF_LLADDR(ifp)); 489 la->la_preempt--; 490 } 491 492 bcopy(LLADDR(sdl), desten, sdl->sdl_alen); 493 return 1; 494 } 495 /* 496 * If ARP is disabled on this interface, stop. 497 * XXX 498 * Probably should not allocate empty llinfo struct if we are 499 * not going to be sending out an arp request. 500 */ 501 if (ifp->if_flags & IFF_NOARP) { 502 m_freem(m); 503 return (0); 504 } 505 /* 506 * There is an arptab entry, but no ethernet address 507 * response yet. Replace the held mbuf with this 508 * latest one. 509 */ 510 if (la->la_hold != NULL) 511 m_freem(la->la_hold); 512 la->la_hold = m; 513 if (rt->rt_expire || ((rt->rt_flags & RTF_STATIC) && !sdl->sdl_alen)) { 514 rt->rt_flags &= ~RTF_REJECT; 515 if (la->la_asked == 0 || rt->rt_expire != time_second) { 516 rt->rt_expire = time_second; 517 if (la->la_asked++ < arp_maxtries) { 518 arprequest(ifp, 519 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 520 &SIN(dst)->sin_addr, 521 IF_LLADDR(ifp)); 522 } else { 523 rt->rt_flags |= RTF_REJECT; 524 rt->rt_expire += arpt_down; 525 la->la_asked = 0; 526 la->la_preempt = arp_maxtries; 527 } 528 529 } 530 } 531 return (0); 532 } 533 534 /* 535 * Common length and type checks are done here, 536 * then the protocol-specific routine is called. 537 */ 538 static int 539 arpintr(struct netmsg *msg) 540 { 541 struct mbuf *m = ((struct netmsg_packet *)msg)->nm_packet; 542 struct arphdr *ar; 543 u_short ar_hrd; 544 545 if (m->m_len < sizeof(struct arphdr) && 546 ((m = m_pullup(m, sizeof(struct arphdr))) == NULL)) { 547 log(LOG_ERR, "arp: runt packet -- m_pullup failed\n"); 548 goto out2; 549 } 550 ar = mtod(m, struct arphdr *); 551 552 ar_hrd = ntohs(ar->ar_hrd); 553 if (ar_hrd != ARPHRD_ETHER && 554 ar_hrd != ARPHRD_IEEE802 && 555 ar_hrd != ARPHRD_ARCNET) { 556 log(LOG_ERR, 557 "arp: unknown hardware address format (0x%2D)\n", 558 (unsigned char *)&ar->ar_hrd, ""); 559 goto out1; 560 } 561 562 if (m->m_pkthdr.len < arphdr_len(ar) && 563 (m = m_pullup(m, arphdr_len(ar))) == NULL) { 564 log(LOG_ERR, "arp: runt packet\n"); 565 goto out1; 566 } 567 568 switch (ntohs(ar->ar_pro)) { 569 #ifdef INET 570 case ETHERTYPE_IP: 571 in_arpinput(m); 572 goto out2; 573 #endif 574 } 575 out1: 576 m_freem(m); 577 out2: 578 lwkt_replymsg(&msg->nm_lmsg, 0); 579 return(EASYNC); 580 } 581 582 #ifdef INET 583 /* 584 * ARP for Internet protocols on 10 Mb/s Ethernet. 585 * Algorithm is that given in RFC 826. 586 * In addition, a sanity check is performed on the sender 587 * protocol address, to catch impersonators. 588 * We no longer handle negotiations for use of trailer protocol: 589 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 590 * along with IP replies if we wanted trailers sent to us, 591 * and also sent them in response to IP replies. 592 * This allowed either end to announce the desire to receive 593 * trailer packets. 594 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 595 * but formerly didn't normally send requests. 596 */ 597 static int log_arp_wrong_iface = 1; 598 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW, 599 &log_arp_wrong_iface, 0, 600 "log arp packets arriving on the wrong interface"); 601 602 static void 603 in_arpinput(struct mbuf *m) 604 { 605 struct arphdr *ah; 606 struct ifnet *ifp = m->m_pkthdr.rcvif; 607 struct ether_header *eh; 608 struct arc_header *arh; 609 struct iso88025_header *th = (struct iso88025_header *)NULL; 610 struct iso88025_sockaddr_dl_data *trld; 611 struct llinfo_arp *la = NULL; 612 struct rtentry *rt; 613 struct ifaddr *ifa; 614 struct in_ifaddr *ia; 615 struct sockaddr_dl *sdl; 616 struct sockaddr sa; 617 struct in_addr isaddr, itaddr, myaddr; 618 int op, rif_len; 619 int req_len; 620 621 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 622 if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) { 623 log(LOG_ERR, "in_arp: runt packet -- m_pullup failed\n"); 624 return; 625 } 626 627 ah = mtod(m, struct arphdr *); 628 op = ntohs(ah->ar_op); 629 memcpy(&isaddr, ar_spa(ah), sizeof isaddr); 630 memcpy(&itaddr, ar_tpa(ah), sizeof itaddr); 631 #ifdef BRIDGE 632 #define BRIDGE_TEST (do_bridge) 633 #else 634 #define BRIDGE_TEST (0) /* cc will optimise the test away */ 635 #endif 636 /* 637 * For a bridge, we want to check the address irrespective 638 * of the receive interface. (This will change slightly 639 * when we have clusters of interfaces). 640 */ 641 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) 642 if ((BRIDGE_TEST || (ia->ia_ifp == ifp)) && 643 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) 644 goto match; 645 LIST_FOREACH(ia, INADDR_HASH(isaddr.s_addr), ia_hash) 646 if ((BRIDGE_TEST || (ia->ia_ifp == ifp)) && 647 isaddr.s_addr == ia->ia_addr.sin_addr.s_addr) 648 goto match; 649 /* 650 * No match, use the first inet address on the receive interface 651 * as a dummy address for the rest of the function. 652 */ 653 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) 654 if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_INET) { 655 ia = ifatoia(ifa); 656 goto match; 657 } 658 /* 659 * If bridging, fall back to using any inet address. 660 * This is probably incorrect, the right way being try to match 661 * addresses for interfaces in the same cluster, so if we 662 * get here we should always drop the packet. 663 */ 664 if (!BRIDGE_TEST || 665 (ia = TAILQ_FIRST(&in_ifaddrhead)) == NULL) { 666 m_freem(m); 667 return; 668 } 669 match: 670 myaddr = ia->ia_addr.sin_addr; 671 if (!bcmp(ar_sha(ah), IF_LLADDR(ifp), ifp->if_addrlen)) { 672 m_freem(m); /* it's from me, ignore it. */ 673 return; 674 } 675 if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) { 676 log(LOG_ERR, 677 "arp: link address is broadcast for IP address %s!\n", 678 inet_ntoa(isaddr)); 679 m_freem(m); 680 return; 681 } 682 if (isaddr.s_addr == myaddr.s_addr && myaddr.s_addr != 0) { 683 log(LOG_ERR, 684 "arp: %*D is using my IP address %s!\n", 685 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 686 inet_ntoa(isaddr)); 687 itaddr = myaddr; 688 goto reply; 689 } 690 la = arplookup(isaddr.s_addr, (itaddr.s_addr == myaddr.s_addr), FALSE); 691 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { 692 /* the following is not an error when doing bridging */ 693 if (!BRIDGE_TEST && rt->rt_ifp != ifp) { 694 if (log_arp_wrong_iface) 695 log(LOG_ERR, 696 "arp: %s is on %s but got reply from %*D on %s\n", 697 inet_ntoa(isaddr), 698 rt->rt_ifp->if_xname, 699 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 700 ifp->if_xname); 701 goto reply; 702 } 703 if (sdl->sdl_alen && 704 bcmp(ar_sha(ah), LLADDR(sdl), sdl->sdl_alen)) { 705 if (rt->rt_expire) 706 log(LOG_INFO, 707 "arp: %s moved from %*D to %*D on %s\n", 708 inet_ntoa(isaddr), 709 ifp->if_addrlen, (u_char *)LLADDR(sdl), ":", 710 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 711 ifp->if_xname); 712 else { 713 log(LOG_ERR, 714 "arp: %*D attempts to modify permanent entry for %s on %s\n", 715 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 716 inet_ntoa(isaddr), ifp->if_xname); 717 goto reply; 718 } 719 } 720 /* 721 * sanity check for the address length. 722 * XXX this does not work for protocols with variable address 723 * length. -is 724 */ 725 if (sdl->sdl_alen && 726 sdl->sdl_alen != ah->ar_hln) { 727 log(LOG_WARNING, 728 "arp from %*D: new addr len %d, was %d", 729 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 730 ah->ar_hln, sdl->sdl_alen); 731 } 732 if (ifp->if_addrlen != ah->ar_hln) { 733 log(LOG_WARNING, 734 "arp from %*D: addr len: new %d, i/f %d (ignored)", 735 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 736 ah->ar_hln, ifp->if_addrlen); 737 goto reply; 738 } 739 memcpy(LLADDR(sdl), ar_sha(ah), sdl->sdl_alen = ah->ar_hln); 740 /* 741 * If we receive an arp from a token-ring station over 742 * a token-ring nic then try to save the source 743 * routing info. 744 */ 745 if (ifp->if_type == IFT_ISO88025) { 746 th = (struct iso88025_header *)m->m_pkthdr.header; 747 trld = SDL_ISO88025(sdl); 748 rif_len = TR_RCF_RIFLEN(th->rcf); 749 if ((th->iso88025_shost[0] & TR_RII) && 750 (rif_len > 2)) { 751 trld->trld_rcf = th->rcf; 752 trld->trld_rcf ^= htons(TR_RCF_DIR); 753 memcpy(trld->trld_route, th->rd, rif_len - 2); 754 trld->trld_rcf &= ~htons(TR_RCF_BCST_MASK); 755 /* 756 * Set up source routing information for 757 * reply packet (XXX) 758 */ 759 m->m_data -= rif_len; 760 m->m_len += rif_len; 761 m->m_pkthdr.len += rif_len; 762 } else { 763 th->iso88025_shost[0] &= ~TR_RII; 764 trld->trld_rcf = 0; 765 } 766 m->m_data -= 8; 767 m->m_len += 8; 768 m->m_pkthdr.len += 8; 769 th->rcf = trld->trld_rcf; 770 } 771 if (rt->rt_expire) 772 rt->rt_expire = time_second + arpt_keep; 773 rt->rt_flags &= ~RTF_REJECT; 774 la->la_asked = 0; 775 la->la_preempt = arp_maxtries; 776 if (la->la_hold != NULL) { 777 m_adj(la->la_hold, sizeof(struct ether_header)); 778 (*ifp->if_output)(ifp, la->la_hold, rt_key(rt), rt); 779 la->la_hold = NULL; 780 } 781 } 782 reply: 783 if (op != ARPOP_REQUEST) { 784 m_freem(m); 785 return; 786 } 787 if (itaddr.s_addr == myaddr.s_addr) { 788 /* I am the target */ 789 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 790 memcpy(ar_sha(ah), IF_LLADDR(ifp), ah->ar_hln); 791 } else { 792 la = arplookup(itaddr.s_addr, FALSE, SIN_PROXY); 793 if (la == NULL) { 794 struct sockaddr_in sin; 795 796 if (!arp_proxyall) { 797 m_freem(m); 798 return; 799 } 800 801 bzero(&sin, sizeof sin); 802 sin.sin_family = AF_INET; 803 sin.sin_len = sizeof sin; 804 sin.sin_addr = itaddr; 805 806 rt = rtpurelookup((struct sockaddr *)&sin); 807 if (rt == NULL) { 808 m_freem(m); 809 return; 810 } 811 --rt->rt_refcnt; 812 /* 813 * Don't send proxies for nodes on the same interface 814 * as this one came out of, or we'll get into a fight 815 * over who claims what Ether address. 816 */ 817 if (rt->rt_ifp == ifp) { 818 m_freem(m); 819 return; 820 } 821 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 822 memcpy(ar_sha(ah), IF_LLADDR(ifp), ah->ar_hln); 823 #ifdef DEBUG_PROXY 824 printf("arp: proxying for %s\n", inet_ntoa(itaddr)); 825 #endif 826 } else { 827 rt = la->la_rt; 828 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 829 sdl = SDL(rt->rt_gateway); 830 memcpy(ar_sha(ah), LLADDR(sdl), ah->ar_hln); 831 } 832 } 833 834 memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln); 835 memcpy(ar_spa(ah), &itaddr, ah->ar_pln); 836 ah->ar_op = htons(ARPOP_REPLY); 837 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 838 switch (ifp->if_type) { 839 case IFT_ARCNET: 840 arh = (struct arc_header *)sa.sa_data; 841 arh->arc_dhost = *ar_tha(ah); 842 arh->arc_type = ARCTYPE_ARP; 843 break; 844 case IFT_ISO88025: 845 /* Re-arrange the source/dest address */ 846 memcpy(th->iso88025_dhost, th->iso88025_shost, 847 sizeof th->iso88025_dhost); 848 memcpy(th->iso88025_shost, IF_LLADDR(ifp), 849 sizeof th->iso88025_shost); 850 /* Set the source routing bit if neccesary */ 851 if (th->iso88025_dhost[0] & TR_RII) { 852 th->iso88025_dhost[0] &= ~TR_RII; 853 if (TR_RCF_RIFLEN(th->rcf) > 2) 854 th->iso88025_shost[0] |= TR_RII; 855 } 856 /* Copy the addresses, ac and fc into sa_data */ 857 memcpy(sa.sa_data, th->iso88025_dhost, 858 (sizeof th->iso88025_dhost) * 2); 859 sa.sa_data[(sizeof th->iso88025_dhost) * 2] = TR_AC; 860 sa.sa_data[(sizeof th->iso88025_dhost) * 2 + 1] = TR_LLC_FRAME; 861 break; 862 case IFT_ETHER: 863 case IFT_FDDI: 864 /* 865 * May not be correct for types not explictly 866 * listed, but it is our best guess. 867 */ 868 default: 869 eh = (struct ether_header *)sa.sa_data; 870 memcpy(eh->ether_dhost, ar_tha(ah), sizeof eh->ether_dhost); 871 eh->ether_type = htons(ETHERTYPE_ARP); 872 break; 873 } 874 sa.sa_family = AF_UNSPEC; 875 sa.sa_len = sizeof sa; 876 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 877 return; 878 } 879 #endif 880 881 /* 882 * Free an arp entry. If the arp entry is actively referenced or represents 883 * a static entry we only clear it back to an unresolved state, otherwise 884 * we destroy the entry entirely. 885 * 886 * Note that static entries are created when route add ... -interface is used 887 * to create an interface route to a (direct) destination. 888 */ 889 static void 890 arptfree(struct llinfo_arp *la) 891 { 892 struct rtentry *rt = la->la_rt; 893 struct sockaddr_dl *sdl; 894 895 if (rt == NULL) 896 panic("arptfree"); 897 sdl = SDL(rt->rt_gateway); 898 if (sdl != NULL && 899 ((rt->rt_refcnt > 0 && sdl->sdl_family == AF_LINK) || 900 (rt->rt_flags & RTF_STATIC))) { 901 sdl->sdl_alen = 0; 902 la->la_preempt = la->la_asked = 0; 903 rt->rt_flags &= ~RTF_REJECT; 904 return; 905 } 906 rtrequest(RTM_DELETE, rt_key(rt), NULL, rt_mask(rt), 0, NULL); 907 } 908 909 /* 910 * Lookup or enter a new address in arptab. 911 */ 912 static struct llinfo_arp * 913 arplookup(in_addr_t addr, boolean_t create, boolean_t proxy) 914 { 915 struct rtentry *rt; 916 struct sockaddr_inarp sin = { sizeof sin, AF_INET }; 917 const char *why = NULL; 918 919 sin.sin_addr.s_addr = addr; 920 sin.sin_other = proxy ? SIN_PROXY : 0; 921 if (create) 922 rt = rtlookup((struct sockaddr *)&sin); 923 else 924 rt = rtpurelookup((struct sockaddr *)&sin); 925 if (rt == NULL) 926 return (NULL); 927 rt->rt_refcnt--; 928 929 if (rt->rt_flags & RTF_GATEWAY) 930 why = "host is not on local network"; 931 else if (!(rt->rt_flags & RTF_LLINFO)) 932 why = "could not allocate llinfo"; 933 else if (rt->rt_gateway->sa_family != AF_LINK) 934 why = "gateway route is not ours"; 935 936 if (why) { 937 if (create) { 938 log(LOG_DEBUG, "arplookup %s failed: %s\n", 939 inet_ntoa(sin.sin_addr), why); 940 } 941 if (rt->rt_refcnt <= 0 && (rt->rt_flags & RTF_WASCLONED)) { 942 /* No references to this route. Purge it. */ 943 rtrequest(RTM_DELETE, rt_key(rt), rt->rt_gateway, 944 rt_mask(rt), rt->rt_flags, NULL); 945 } 946 return (NULL); 947 } 948 return (rt->rt_llinfo); 949 } 950 951 void 952 arp_ifinit(struct ifnet *ifp, struct ifaddr *ifa) 953 { 954 if (IA_SIN(ifa)->sin_addr.s_addr != INADDR_ANY) 955 arprequest(ifp, &IA_SIN(ifa)->sin_addr, &IA_SIN(ifa)->sin_addr, 956 IF_LLADDR(ifp)); 957 ifa->ifa_rtrequest = arp_rtrequest; 958 ifa->ifa_flags |= RTF_CLONING; 959 } 960 961 static void 962 arp_init(void) 963 { 964 LIST_INIT(&llinfo_arp); 965 netisr_register(NETISR_ARP, cpu0_portfn, arpintr); 966 } 967 968 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0); 969