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 1.49 2008/06/09 11:24:24 sephe 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 89 #include <net/if.h> 90 #include <net/if_dl.h> 91 #include <net/if_types.h> 92 #include <net/route.h> 93 #include <net/netisr.h> 94 #include <net/if_llc.h> 95 96 #include <netinet/in.h> 97 #include <netinet/in_var.h> 98 #include <netinet/if_ether.h> 99 100 #include <sys/thread2.h> 101 #include <sys/msgport2.h> 102 #include <net/netmsg2.h> 103 104 105 #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 void arprequest_acces(struct ifnet *ifp, struct in_addr *sip, struct in_addr *tip, u_char *enaddr); 151 static void arp_rtrequest (int, struct rtentry *, struct rt_addrinfo *); 152 static void arprequest (struct ifnet *, 153 struct in_addr *, struct in_addr *, u_char *); 154 static void arpintr(struct netmsg *); 155 static void arptfree (struct llinfo_arp *); 156 static void arptimer (void *); 157 static struct llinfo_arp 158 *arplookup (in_addr_t addr, boolean_t create, boolean_t proxy); 159 #ifdef INET 160 static void in_arpinput (struct mbuf *); 161 #endif 162 163 static struct callout arptimer_ch[MAXCPU]; 164 165 /* 166 * Timeout routine. Age arp_tab entries periodically. 167 */ 168 /* ARGSUSED */ 169 static void 170 arptimer(void *ignored_arg) 171 { 172 struct llinfo_arp *la, *nla; 173 174 crit_enter(); 175 LIST_FOREACH_MUTABLE(la, &llinfo_arp_list[mycpuid], la_le, nla) { 176 if (la->la_rt->rt_expire && la->la_rt->rt_expire <= time_second) 177 arptfree(la); 178 } 179 callout_reset(&arptimer_ch[mycpuid], arpt_prune * hz, arptimer, NULL); 180 crit_exit(); 181 } 182 183 /* 184 * Parallel to llc_rtrequest. 185 */ 186 static void 187 arp_rtrequest(int req, struct rtentry *rt, struct rt_addrinfo *info) 188 { 189 struct sockaddr *gate = rt->rt_gateway; 190 struct llinfo_arp *la = rt->rt_llinfo; 191 192 struct sockaddr_dl null_sdl = { sizeof null_sdl, AF_LINK }; 193 static boolean_t arpinit_done[MAXCPU]; 194 195 if (!arpinit_done[mycpuid]) { 196 arpinit_done[mycpuid] = TRUE; 197 callout_init(&arptimer_ch[mycpuid]); 198 callout_reset(&arptimer_ch[mycpuid], hz, arptimer, NULL); 199 } 200 if (rt->rt_flags & RTF_GATEWAY) 201 return; 202 203 switch (req) { 204 case RTM_ADD: 205 /* 206 * XXX: If this is a manually added route to interface 207 * such as older version of routed or gated might provide, 208 * restore cloning bit. 209 */ 210 if (!(rt->rt_flags & RTF_HOST) && 211 SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff) 212 rt->rt_flags |= RTF_CLONING; 213 if (rt->rt_flags & RTF_CLONING) { 214 /* 215 * Case 1: This route should come from a route to iface. 216 */ 217 rt_setgate(rt, rt_key(rt), 218 (struct sockaddr *)&null_sdl); 219 gate = rt->rt_gateway; 220 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 221 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 222 rt->rt_expire = time_second; 223 break; 224 } 225 /* Announce a new entry if requested. */ 226 if (rt->rt_flags & RTF_ANNOUNCE) { 227 arprequest(rt->rt_ifp, 228 &SIN(rt_key(rt))->sin_addr, 229 &SIN(rt_key(rt))->sin_addr, 230 LLADDR(SDL(gate))); 231 } 232 /*FALLTHROUGH*/ 233 case RTM_RESOLVE: 234 if (gate->sa_family != AF_LINK || 235 gate->sa_len < sizeof(struct sockaddr_dl)) { 236 log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n"); 237 break; 238 } 239 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 240 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 241 if (la != NULL) 242 break; /* This happens on a route change */ 243 /* 244 * Case 2: This route may come from cloning, or a manual route 245 * add with a LL address. 246 */ 247 R_Malloc(la, struct llinfo_arp *, sizeof *la); 248 rt->rt_llinfo = la; 249 if (la == NULL) { 250 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); 251 break; 252 } 253 bzero(la, sizeof *la); 254 la->la_rt = rt; 255 rt->rt_flags |= RTF_LLINFO; 256 LIST_INSERT_HEAD(&llinfo_arp_list[mycpuid], la, la_le); 257 258 #ifdef INET 259 /* 260 * This keeps the multicast addresses from showing up 261 * in `arp -a' listings as unresolved. It's not actually 262 * functional. Then the same for broadcast. 263 */ 264 if (IN_MULTICAST(ntohl(SIN(rt_key(rt))->sin_addr.s_addr))) { 265 ETHER_MAP_IP_MULTICAST(&SIN(rt_key(rt))->sin_addr, 266 LLADDR(SDL(gate))); 267 SDL(gate)->sdl_alen = 6; 268 rt->rt_expire = 0; 269 } 270 if (in_broadcast(SIN(rt_key(rt))->sin_addr, rt->rt_ifp)) { 271 memcpy(LLADDR(SDL(gate)), rt->rt_ifp->if_broadcastaddr, 272 rt->rt_ifp->if_addrlen); 273 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen; 274 rt->rt_expire = 0; 275 } 276 #endif 277 278 if (SIN(rt_key(rt))->sin_addr.s_addr == 279 (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) { 280 /* 281 * This test used to be 282 * if (loif.if_flags & IFF_UP) 283 * It allowed local traffic to be forced 284 * through the hardware by configuring the 285 * loopback down. However, it causes problems 286 * during network configuration for boards 287 * that can't receive packets they send. It 288 * is now necessary to clear "useloopback" and 289 * remove the route to force traffic out to 290 * the hardware. 291 */ 292 rt->rt_expire = 0; 293 bcopy(IF_LLADDR(rt->rt_ifp), LLADDR(SDL(gate)), 294 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen); 295 if (useloopback) 296 rt->rt_ifp = loif; 297 } 298 break; 299 300 case RTM_DELETE: 301 if (la == NULL) 302 break; 303 LIST_REMOVE(la, la_le); 304 rt->rt_llinfo = NULL; 305 rt->rt_flags &= ~RTF_LLINFO; 306 if (la->la_hold != NULL) 307 m_freem(la->la_hold); 308 Free(la); 309 } 310 } 311 312 /* 313 * Broadcast an ARP request. Caller specifies: 314 * - arp header source ip address 315 * - arp header target ip address 316 * - arp header source ethernet address 317 */ 318 static void 319 arprequest(struct ifnet *ifp, struct in_addr *sip, struct in_addr *tip, 320 u_char *enaddr) 321 { 322 struct mbuf *m; 323 struct ether_header *eh; 324 struct arphdr *ah; 325 struct sockaddr sa; 326 u_short ar_hrd; 327 328 if ((m = m_gethdr(MB_DONTWAIT, MT_DATA)) == NULL) 329 return; 330 m->m_pkthdr.rcvif = (struct ifnet *)NULL; 331 332 switch (ifp->if_type) { 333 case IFT_ETHER: 334 /* 335 * This may not be correct for types not explicitly 336 * listed, but this is our best guess 337 */ 338 default: 339 ar_hrd = htons(ARPHRD_ETHER); 340 341 m->m_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 342 m->m_pkthdr.len = m->m_len; 343 MH_ALIGN(m, m->m_len); 344 345 eh = (struct ether_header *)sa.sa_data; 346 /* if_output() will not swap */ 347 eh->ether_type = htons(ETHERTYPE_ARP); 348 memcpy(eh->ether_dhost, ifp->if_broadcastaddr, ifp->if_addrlen); 349 350 ah = mtod(m, struct arphdr *); 351 break; 352 } 353 354 ah->ar_hrd = ar_hrd; 355 ah->ar_pro = htons(ETHERTYPE_IP); 356 ah->ar_hln = ifp->if_addrlen; /* hardware address length */ 357 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 358 ah->ar_op = htons(ARPOP_REQUEST); 359 memcpy(ar_sha(ah), enaddr, ah->ar_hln); 360 memset(ar_tha(ah), 0, ah->ar_hln); 361 memcpy(ar_spa(ah), sip, ah->ar_pln); 362 memcpy(ar_tpa(ah), tip, ah->ar_pln); 363 364 sa.sa_family = AF_UNSPEC; 365 sa.sa_len = sizeof sa; 366 ifp->if_output(ifp, m, &sa, (struct rtentry *)NULL); 367 } 368 369 /* 370 * Resolve an IP address into an ethernet address. If success, 371 * desten is filled in. If there is no entry in arptab, 372 * set one up and broadcast a request for the IP address. 373 * Hold onto this mbuf and resend it once the address 374 * is finally resolved. A return value of 1 indicates 375 * that desten has been filled in and the packet should be sent 376 * normally; a 0 return indicates that the packet has been 377 * taken over here, either now or for later transmission. 378 */ 379 int 380 arpresolve( 381 struct ifnet *ifp, 382 struct rtentry *rt0, 383 struct mbuf *m, 384 struct sockaddr *dst, 385 u_char *desten) 386 { 387 struct rtentry *rt; 388 struct llinfo_arp *la = NULL; 389 struct sockaddr_dl *sdl; 390 391 if (m->m_flags & M_BCAST) { /* broadcast */ 392 memcpy(desten, ifp->if_broadcastaddr, ifp->if_addrlen); 393 return (1); 394 } 395 if (m->m_flags & M_MCAST) {/* multicast */ 396 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); 397 return (1); 398 } 399 if (rt0 != NULL) { 400 if (rt_llroute(dst, rt0, &rt) != 0) { 401 m_freem(m); 402 return 0; 403 } 404 la = rt->rt_llinfo; 405 } 406 if (la == NULL) { 407 la = arplookup(SIN(dst)->sin_addr.s_addr, TRUE, FALSE); 408 if (la != NULL) 409 rt = la->la_rt; 410 } 411 if (la == NULL || rt == NULL) { 412 log(LOG_DEBUG, "arpresolve: can't allocate llinfo for %s%s%s\n", 413 inet_ntoa(SIN(dst)->sin_addr), la ? "la" : " ", 414 rt ? "rt" : ""); 415 m_freem(m); 416 return (0); 417 } 418 sdl = SDL(rt->rt_gateway); 419 /* 420 * Check the address family and length is valid, the address 421 * is resolved; otherwise, try to resolve. 422 */ 423 if ((rt->rt_expire == 0 || rt->rt_expire > time_second) && 424 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 425 /* 426 * If entry has an expiry time and it is approaching, 427 * see if we need to send an ARP request within this 428 * arpt_down interval. 429 */ 430 if ((rt->rt_expire != 0) && 431 (time_second + la->la_preempt > rt->rt_expire)) { 432 arprequest(ifp, 433 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 434 &SIN(dst)->sin_addr, 435 IF_LLADDR(ifp)); 436 la->la_preempt--; 437 } 438 439 bcopy(LLADDR(sdl), desten, sdl->sdl_alen); 440 return 1; 441 } 442 /* 443 * If ARP is disabled on this interface, stop. 444 * XXX 445 * Probably should not allocate empty llinfo struct if we are 446 * not going to be sending out an arp request. 447 */ 448 if (ifp->if_flags & IFF_NOARP) { 449 m_freem(m); 450 return (0); 451 } 452 /* 453 * There is an arptab entry, but no ethernet address 454 * response yet. Replace the held mbuf with this 455 * latest one. 456 */ 457 if (la->la_hold != NULL) 458 m_freem(la->la_hold); 459 la->la_hold = m; 460 if (rt->rt_expire || ((rt->rt_flags & RTF_STATIC) && !sdl->sdl_alen)) { 461 rt->rt_flags &= ~RTF_REJECT; 462 if (la->la_asked == 0 || rt->rt_expire != time_second) { 463 rt->rt_expire = time_second; 464 if (la->la_asked++ < arp_maxtries) { 465 arprequest(ifp, 466 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 467 &SIN(dst)->sin_addr, 468 IF_LLADDR(ifp)); 469 } else { 470 rt->rt_flags |= RTF_REJECT; 471 rt->rt_expire += arpt_down; 472 la->la_asked = 0; 473 la->la_preempt = arp_maxtries; 474 } 475 476 } 477 } 478 return (0); 479 } 480 481 /* 482 * Common length and type checks are done here, 483 * then the protocol-specific routine is called. 484 */ 485 static void 486 arpintr(struct netmsg *msg) 487 { 488 struct mbuf *m = ((struct netmsg_packet *)msg)->nm_packet; 489 struct arphdr *ar; 490 u_short ar_hrd; 491 492 if (m->m_len < sizeof(struct arphdr) && 493 (m = m_pullup(m, sizeof(struct arphdr))) == NULL) { 494 log(LOG_ERR, "arp: runt packet -- m_pullup failed\n"); 495 return; 496 } 497 ar = mtod(m, struct arphdr *); 498 499 ar_hrd = ntohs(ar->ar_hrd); 500 if (ar_hrd != ARPHRD_ETHER && ar_hrd != ARPHRD_IEEE802) { 501 log(LOG_ERR, "arp: unknown hardware address format (0x%2D)\n", 502 (unsigned char *)&ar->ar_hrd, ""); 503 m_freem(m); 504 return; 505 } 506 507 if (m->m_pkthdr.len < arphdr_len(ar)) { 508 if ((m = m_pullup(m, arphdr_len(ar))) == NULL) { 509 log(LOG_ERR, "arp: runt packet\n"); 510 return; 511 } 512 ar = mtod(m, struct arphdr *); 513 } 514 515 switch (ntohs(ar->ar_pro)) { 516 #ifdef INET 517 case ETHERTYPE_IP: 518 in_arpinput(m); 519 return; 520 #endif 521 } 522 m_freem(m); 523 /* msg was embedded in the mbuf, do not reply! */ 524 } 525 526 #ifdef INET 527 /* 528 * ARP for Internet protocols on 10 Mb/s Ethernet. 529 * Algorithm is that given in RFC 826. 530 * In addition, a sanity check is performed on the sender 531 * protocol address, to catch impersonators. 532 * We no longer handle negotiations for use of trailer protocol: 533 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 534 * along with IP replies if we wanted trailers sent to us, 535 * and also sent them in response to IP replies. 536 * This allowed either end to announce the desire to receive 537 * trailer packets. 538 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 539 * but formerly didn't normally send requests. 540 */ 541 static int log_arp_wrong_iface = 1; 542 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW, 543 &log_arp_wrong_iface, 0, 544 "log arp packets arriving on the wrong interface"); 545 546 static void 547 arp_update_oncpu(struct mbuf *m, in_addr_t saddr, boolean_t create, 548 boolean_t dologging) 549 { 550 struct arphdr *ah = mtod(m, struct arphdr *); 551 struct ifnet *ifp = m->m_pkthdr.rcvif; 552 struct llinfo_arp *la; 553 struct sockaddr_dl *sdl; 554 struct rtentry *rt; 555 int cpu = mycpuid; 556 557 la = arplookup(saddr, create, FALSE); 558 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { 559 struct in_addr isaddr = { saddr }; 560 561 /* the following is not an error when doing bridging */ 562 if (rt->rt_ifp != ifp) { 563 if (dologging && log_arp_wrong_iface && cpu == 0) { 564 log(LOG_ERR, 565 "arp: %s is on %s " 566 "but got reply from %*D on %s\n", 567 inet_ntoa(isaddr), 568 rt->rt_ifp->if_xname, 569 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 570 ifp->if_xname); 571 } 572 return; 573 } 574 if (sdl->sdl_alen && 575 bcmp(ar_sha(ah), LLADDR(sdl), sdl->sdl_alen)) { 576 if (rt->rt_expire != 0) { 577 if (dologging && cpu == 0) { 578 log(LOG_INFO, 579 "arp: %s moved from %*D to %*D on %s\n", 580 inet_ntoa(isaddr), 581 ifp->if_addrlen, (u_char *)LLADDR(sdl), 582 ":", ifp->if_addrlen, 583 (u_char *)ar_sha(ah), ":", 584 ifp->if_xname); 585 } 586 } else { 587 if (dologging && cpu == 0) { 588 log(LOG_ERR, 589 "arp: %*D attempts to modify permanent entry for %s on %s\n", 590 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 591 inet_ntoa(isaddr), ifp->if_xname); 592 } 593 return; 594 } 595 } 596 /* 597 * sanity check for the address length. 598 * XXX this does not work for protocols with variable address 599 * length. -is 600 */ 601 if (dologging && sdl->sdl_alen && sdl->sdl_alen != ah->ar_hln && 602 cpu == 0) 603 { 604 log(LOG_WARNING, 605 "arp from %*D: new addr len %d, was %d", 606 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 607 ah->ar_hln, sdl->sdl_alen); 608 } 609 if (ifp->if_addrlen != ah->ar_hln) { 610 if (dologging && cpu == 0) { 611 log(LOG_WARNING, 612 "arp from %*D: addr len: new %d, i/f %d (ignored)", 613 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 614 ah->ar_hln, ifp->if_addrlen); 615 } 616 return; 617 } 618 memcpy(LLADDR(sdl), ar_sha(ah), sdl->sdl_alen = ah->ar_hln); 619 if (rt->rt_expire != 0) 620 rt->rt_expire = time_second + arpt_keep; 621 rt->rt_flags &= ~RTF_REJECT; 622 la->la_asked = 0; 623 la->la_preempt = arp_maxtries; 624 625 /* 626 * This particular cpu might have been holding an mbuf 627 * pending ARP resolution. If so, transmit the mbuf now. 628 */ 629 if (la->la_hold != NULL) { 630 m_adj(la->la_hold, sizeof(struct ether_header)); 631 ifp->if_output(ifp, la->la_hold, rt_key(rt), rt); 632 la->la_hold = NULL; 633 } 634 } 635 } 636 637 #ifdef SMP 638 639 struct netmsg_arp_update { 640 struct netmsg netmsg; 641 struct mbuf *m; 642 in_addr_t saddr; 643 boolean_t create; 644 }; 645 646 static void arp_update_msghandler(struct netmsg *netmsg); 647 648 #endif 649 650 /* 651 * Called from arpintr() - this routine is run from a single cpu. 652 */ 653 static void 654 in_arpinput(struct mbuf *m) 655 { 656 struct arphdr *ah; 657 struct ifnet *ifp = m->m_pkthdr.rcvif; 658 struct ether_header *eh; 659 struct rtentry *rt; 660 struct ifaddr_container *ifac; 661 struct in_ifaddr_container *iac; 662 struct in_ifaddr *ia; 663 struct sockaddr sa; 664 struct in_addr isaddr, itaddr, myaddr; 665 #ifdef SMP 666 struct netmsg_arp_update msg; 667 #endif 668 u_int8_t *enaddr = NULL; 669 int op; 670 int req_len; 671 672 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 673 if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) { 674 log(LOG_ERR, "in_arp: runt packet -- m_pullup failed\n"); 675 return; 676 } 677 678 ah = mtod(m, struct arphdr *); 679 op = ntohs(ah->ar_op); 680 memcpy(&isaddr, ar_spa(ah), sizeof isaddr); 681 memcpy(&itaddr, ar_tpa(ah), sizeof itaddr); 682 /* 683 * Check both target and sender IP addresses: 684 * 685 * If we receive the packet on the interface owning the address, 686 * then accept the address. 687 * 688 * For a bridge, we accept the address if the receive interface and 689 * the interface owning the address are on the same bridge. 690 * (This will change slightly when we have clusters of interfaces). 691 */ 692 LIST_FOREACH(iac, INADDR_HASH(itaddr.s_addr), ia_hash) { 693 ia = iac->ia; 694 695 /* Skip all ia's which don't match */ 696 if (itaddr.s_addr != ia->ia_addr.sin_addr.s_addr) 697 continue; 698 699 if (ia->ia_ifp == ifp) 700 goto match; 701 702 if (ifp->if_bridge && ia->ia_ifp && 703 ifp->if_bridge == ia->ia_ifp->if_bridge) 704 goto match; 705 706 #ifdef CARP 707 /* 708 * If the interface does not match, but the recieving interface 709 * is part of carp, we call carp_iamatch to see if this is a 710 * request for the virtual host ip. 711 * XXX: This is really ugly! 712 */ 713 if (ifp->if_carp != NULL && 714 carp_iamatch(ifp->if_carp, ia, &isaddr, &enaddr) && 715 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) 716 goto match; 717 #endif 718 } 719 LIST_FOREACH(iac, INADDR_HASH(isaddr.s_addr), ia_hash) { 720 ia = iac->ia; 721 722 /* Skip all ia's which don't match */ 723 if (isaddr.s_addr != ia->ia_addr.sin_addr.s_addr) 724 continue; 725 726 if (ia->ia_ifp == ifp) 727 goto match; 728 729 if (ifp->if_bridge && ia->ia_ifp && 730 ifp->if_bridge == ia->ia_ifp->if_bridge) 731 goto match; 732 } 733 /* 734 * No match, use the first inet address on the receive interface 735 * as a dummy address for the rest of the function. 736 */ 737 TAILQ_FOREACH(ifac, &ifp->if_addrheads[mycpuid], ifa_link) { 738 struct ifaddr *ifa = ifac->ifa; 739 740 if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_INET) { 741 ia = ifatoia(ifa); 742 goto match; 743 } 744 } 745 /* 746 * If we got here, we didn't find any suitable interface, 747 * so drop the packet. 748 */ 749 m_freem(m); 750 return; 751 752 match: 753 if (!enaddr) 754 enaddr = (u_int8_t *)IF_LLADDR(ifp); 755 myaddr = ia->ia_addr.sin_addr; 756 if (!bcmp(ar_sha(ah), enaddr, ifp->if_addrlen)) { 757 m_freem(m); /* it's from me, ignore it. */ 758 return; 759 } 760 if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) { 761 log(LOG_ERR, 762 "arp: link address is broadcast for IP address %s!\n", 763 inet_ntoa(isaddr)); 764 m_freem(m); 765 return; 766 } 767 if (isaddr.s_addr == myaddr.s_addr && myaddr.s_addr != 0) { 768 log(LOG_ERR, 769 "arp: %*D is using my IP address %s!\n", 770 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 771 inet_ntoa(isaddr)); 772 itaddr = myaddr; 773 goto reply; 774 } 775 #ifdef SMP 776 netmsg_init(&msg.netmsg, &curthread->td_msgport, 0, 777 arp_update_msghandler); 778 msg.m = m; 779 msg.saddr = isaddr.s_addr; 780 msg.create = (itaddr.s_addr == myaddr.s_addr); 781 lwkt_domsg(rtable_portfn(0), &msg.netmsg.nm_lmsg, 0); 782 #endif 783 arp_update_oncpu(m, isaddr.s_addr, (itaddr.s_addr == myaddr.s_addr), 784 TRUE); 785 reply: 786 if (op != ARPOP_REQUEST) { 787 m_freem(m); 788 return; 789 } 790 if (itaddr.s_addr == myaddr.s_addr) { 791 /* I am the target */ 792 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 793 memcpy(ar_sha(ah), enaddr, ah->ar_hln); 794 } else { 795 struct llinfo_arp *la; 796 797 la = arplookup(itaddr.s_addr, FALSE, SIN_PROXY); 798 if (la == NULL) { 799 struct sockaddr_in sin; 800 801 if (!arp_proxyall) { 802 m_freem(m); 803 return; 804 } 805 806 bzero(&sin, sizeof sin); 807 sin.sin_family = AF_INET; 808 sin.sin_len = sizeof sin; 809 sin.sin_addr = itaddr; 810 811 rt = rtpurelookup((struct sockaddr *)&sin); 812 if (rt == NULL) { 813 m_freem(m); 814 return; 815 } 816 --rt->rt_refcnt; 817 /* 818 * Don't send proxies for nodes on the same interface 819 * as this one came out of, or we'll get into a fight 820 * over who claims what Ether address. 821 */ 822 if (rt->rt_ifp == ifp) { 823 m_freem(m); 824 return; 825 } 826 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 827 memcpy(ar_sha(ah), enaddr, ah->ar_hln); 828 #ifdef DEBUG_PROXY 829 kprintf("arp: proxying for %s\n", inet_ntoa(itaddr)); 830 #endif 831 } else { 832 struct sockaddr_dl *sdl; 833 834 rt = la->la_rt; 835 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 836 sdl = SDL(rt->rt_gateway); 837 memcpy(ar_sha(ah), LLADDR(sdl), ah->ar_hln); 838 } 839 } 840 841 memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln); 842 memcpy(ar_spa(ah), &itaddr, ah->ar_pln); 843 ah->ar_op = htons(ARPOP_REPLY); 844 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 845 switch (ifp->if_type) { 846 case IFT_ETHER: 847 /* 848 * May not be correct for types not explictly 849 * listed, but it is our best guess. 850 */ 851 default: 852 eh = (struct ether_header *)sa.sa_data; 853 memcpy(eh->ether_dhost, ar_tha(ah), sizeof eh->ether_dhost); 854 eh->ether_type = htons(ETHERTYPE_ARP); 855 break; 856 } 857 sa.sa_family = AF_UNSPEC; 858 sa.sa_len = sizeof sa; 859 ifp->if_output(ifp, m, &sa, (struct rtentry *)0); 860 return; 861 } 862 863 #ifdef SMP 864 865 static 866 void 867 arp_update_msghandler(struct netmsg *netmsg) 868 { 869 struct netmsg_arp_update *msg = (struct netmsg_arp_update *)netmsg; 870 int nextcpu; 871 872 arp_update_oncpu(msg->m, msg->saddr, msg->create, FALSE); 873 874 nextcpu = mycpuid + 1; 875 if (nextcpu < ncpus) { 876 lwkt_forwardmsg(rtable_portfn(nextcpu), &msg->netmsg.nm_lmsg); 877 } else { 878 lwkt_replymsg(&msg->netmsg.nm_lmsg, 0); 879 } 880 } 881 882 #endif 883 884 #endif 885 886 /* 887 * Free an arp entry. If the arp entry is actively referenced or represents 888 * a static entry we only clear it back to an unresolved state, otherwise 889 * we destroy the entry entirely. 890 * 891 * Note that static entries are created when route add ... -interface is used 892 * to create an interface route to a (direct) destination. 893 */ 894 static void 895 arptfree(struct llinfo_arp *la) 896 { 897 struct rtentry *rt = la->la_rt; 898 struct sockaddr_dl *sdl; 899 900 if (rt == NULL) 901 panic("arptfree"); 902 sdl = SDL(rt->rt_gateway); 903 if (sdl != NULL && 904 ((rt->rt_refcnt > 0 && sdl->sdl_family == AF_LINK) || 905 (rt->rt_flags & RTF_STATIC))) { 906 sdl->sdl_alen = 0; 907 la->la_preempt = la->la_asked = 0; 908 rt->rt_flags &= ~RTF_REJECT; 909 return; 910 } 911 rtrequest(RTM_DELETE, rt_key(rt), NULL, rt_mask(rt), 0, NULL); 912 } 913 914 /* 915 * Lookup or enter a new address in arptab. 916 */ 917 static struct llinfo_arp * 918 arplookup(in_addr_t addr, boolean_t create, boolean_t proxy) 919 { 920 struct rtentry *rt; 921 struct sockaddr_inarp sin = { sizeof sin, AF_INET }; 922 const char *why = NULL; 923 924 sin.sin_addr.s_addr = addr; 925 sin.sin_other = proxy ? SIN_PROXY : 0; 926 if (create) 927 rt = rtlookup((struct sockaddr *)&sin); 928 else 929 rt = rtpurelookup((struct sockaddr *)&sin); 930 if (rt == NULL) 931 return (NULL); 932 rt->rt_refcnt--; 933 934 if (rt->rt_flags & RTF_GATEWAY) 935 why = "host is not on local network"; 936 else if (!(rt->rt_flags & RTF_LLINFO)) 937 why = "could not allocate llinfo"; 938 else if (rt->rt_gateway->sa_family != AF_LINK) 939 why = "gateway route is not ours"; 940 941 if (why) { 942 if (create) { 943 log(LOG_DEBUG, "arplookup %s failed: %s\n", 944 inet_ntoa(sin.sin_addr), why); 945 } 946 if (rt->rt_refcnt <= 0 && (rt->rt_flags & RTF_WASCLONED)) { 947 /* No references to this route. Purge it. */ 948 rtrequest(RTM_DELETE, rt_key(rt), rt->rt_gateway, 949 rt_mask(rt), rt->rt_flags, NULL); 950 } 951 return (NULL); 952 } 953 return (rt->rt_llinfo); 954 } 955 956 void 957 arp_ifinit(struct ifnet *ifp, struct ifaddr *ifa) 958 { 959 ASSERT_SERIALIZED(ifp->if_serializer); 960 961 if (IA_SIN(ifa)->sin_addr.s_addr != INADDR_ANY) { 962 lwkt_serialize_exit(ifp->if_serializer); 963 arprequest(ifp, &IA_SIN(ifa)->sin_addr, &IA_SIN(ifa)->sin_addr, 964 IF_LLADDR(ifp)); 965 lwkt_serialize_enter(ifp->if_serializer); 966 } 967 ifa->ifa_rtrequest = arp_rtrequest; 968 ifa->ifa_flags |= RTF_CLONING; 969 } 970 971 void 972 arp_ifinit2(struct ifnet *ifp, struct ifaddr *ifa, u_char *enaddr) 973 { 974 ASSERT_NOT_SERIALIZED(ifp->if_serializer); 975 976 if (IA_SIN(ifa)->sin_addr.s_addr != INADDR_ANY) 977 arprequest(ifp, &IA_SIN(ifa)->sin_addr, &IA_SIN(ifa)->sin_addr, 978 enaddr); 979 ifa->ifa_rtrequest = arp_rtrequest; 980 ifa->ifa_flags |= RTF_CLONING; 981 } 982 983 static void 984 arp_init(void) 985 { 986 int cpu; 987 988 for (cpu = 0; cpu < ncpus2; cpu++) 989 LIST_INIT(&llinfo_arp_list[cpu]); 990 netisr_register(NETISR_ARP, cpu0_portfn, arpintr); 991 } 992 993 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0); 994