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 1.46 2008/05/14 11:59:24 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 goto out2; 496 } 497 ar = mtod(m, struct arphdr *); 498 499 ar_hrd = ntohs(ar->ar_hrd); 500 if (ar_hrd != ARPHRD_ETHER && 501 ar_hrd != ARPHRD_IEEE802) { 502 log(LOG_ERR, 503 "arp: unknown hardware address format (0x%2D)\n", 504 (unsigned char *)&ar->ar_hrd, ""); 505 goto out1; 506 } 507 508 if (m->m_pkthdr.len < arphdr_len(ar) && 509 (m = m_pullup(m, arphdr_len(ar))) == NULL) { 510 log(LOG_ERR, "arp: runt packet\n"); 511 goto out1; 512 } 513 514 switch (ntohs(ar->ar_pro)) { 515 #ifdef INET 516 case ETHERTYPE_IP: 517 in_arpinput(m); 518 goto out2; 519 #endif 520 } 521 out1: 522 m_freem(m); 523 out2: 524 ; 525 /* msg was embedded in the mbuf, do not reply! */ 526 } 527 528 #ifdef INET 529 /* 530 * ARP for Internet protocols on 10 Mb/s Ethernet. 531 * Algorithm is that given in RFC 826. 532 * In addition, a sanity check is performed on the sender 533 * protocol address, to catch impersonators. 534 * We no longer handle negotiations for use of trailer protocol: 535 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 536 * along with IP replies if we wanted trailers sent to us, 537 * and also sent them in response to IP replies. 538 * This allowed either end to announce the desire to receive 539 * trailer packets. 540 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 541 * but formerly didn't normally send requests. 542 */ 543 static int log_arp_wrong_iface = 1; 544 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW, 545 &log_arp_wrong_iface, 0, 546 "log arp packets arriving on the wrong interface"); 547 548 static void 549 arp_update_oncpu(struct mbuf *m, in_addr_t saddr, boolean_t create, 550 boolean_t dologging) 551 { 552 struct arphdr *ah = mtod(m, struct arphdr *); 553 struct ifnet *ifp = m->m_pkthdr.rcvif; 554 struct llinfo_arp *la; 555 struct sockaddr_dl *sdl; 556 struct rtentry *rt; 557 int cpu = mycpuid; 558 559 la = arplookup(saddr, create, FALSE); 560 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { 561 struct in_addr isaddr = { saddr }; 562 563 /* the following is not an error when doing bridging */ 564 if (rt->rt_ifp != ifp) { 565 if (dologging && log_arp_wrong_iface && cpu == 0) { 566 log(LOG_ERR, 567 "arp: %s is on %s " 568 "but got reply from %*D on %s\n", 569 inet_ntoa(isaddr), 570 rt->rt_ifp->if_xname, 571 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 572 ifp->if_xname); 573 } 574 return; 575 } 576 if (sdl->sdl_alen && 577 bcmp(ar_sha(ah), LLADDR(sdl), sdl->sdl_alen)) { 578 if (rt->rt_expire != 0) { 579 if (dologging && cpu == 0) { 580 log(LOG_INFO, 581 "arp: %s moved from %*D to %*D on %s\n", 582 inet_ntoa(isaddr), 583 ifp->if_addrlen, (u_char *)LLADDR(sdl), 584 ":", ifp->if_addrlen, 585 (u_char *)ar_sha(ah), ":", 586 ifp->if_xname); 587 } 588 } else { 589 if (dologging && cpu == 0) { 590 log(LOG_ERR, 591 "arp: %*D attempts to modify permanent entry for %s on %s\n", 592 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 593 inet_ntoa(isaddr), ifp->if_xname); 594 } 595 return; 596 } 597 } 598 /* 599 * sanity check for the address length. 600 * XXX this does not work for protocols with variable address 601 * length. -is 602 */ 603 if (dologging && sdl->sdl_alen && sdl->sdl_alen != ah->ar_hln && 604 cpu == 0) 605 { 606 log(LOG_WARNING, 607 "arp from %*D: new addr len %d, was %d", 608 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 609 ah->ar_hln, sdl->sdl_alen); 610 } 611 if (ifp->if_addrlen != ah->ar_hln) { 612 if (dologging && cpu == 0) { 613 log(LOG_WARNING, 614 "arp from %*D: addr len: new %d, i/f %d (ignored)", 615 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 616 ah->ar_hln, ifp->if_addrlen); 617 } 618 return; 619 } 620 memcpy(LLADDR(sdl), ar_sha(ah), sdl->sdl_alen = ah->ar_hln); 621 if (rt->rt_expire != 0) 622 rt->rt_expire = time_second + arpt_keep; 623 rt->rt_flags &= ~RTF_REJECT; 624 la->la_asked = 0; 625 la->la_preempt = arp_maxtries; 626 627 /* 628 * This particular cpu might have been holding an mbuf 629 * pending ARP resolution. If so, transmit the mbuf now. 630 */ 631 if (la->la_hold != NULL) { 632 m_adj(la->la_hold, sizeof(struct ether_header)); 633 ifp->if_output(ifp, la->la_hold, rt_key(rt), rt); 634 la->la_hold = NULL; 635 } 636 } 637 } 638 639 #ifdef SMP 640 641 struct netmsg_arp_update { 642 struct netmsg netmsg; 643 struct mbuf *m; 644 in_addr_t saddr; 645 boolean_t create; 646 }; 647 648 static void arp_update_msghandler(struct netmsg *netmsg); 649 650 #endif 651 652 /* 653 * Called from arpintr() - this routine is run from a single cpu. 654 */ 655 static void 656 in_arpinput(struct mbuf *m) 657 { 658 struct arphdr *ah; 659 struct ifnet *ifp = m->m_pkthdr.rcvif; 660 struct ether_header *eh; 661 struct rtentry *rt; 662 struct ifaddr_container *ifac; 663 struct in_ifaddr *ia; 664 struct sockaddr sa; 665 struct in_addr isaddr, itaddr, myaddr; 666 #ifdef SMP 667 struct netmsg_arp_update msg; 668 #endif 669 u_int8_t *enaddr = NULL; 670 int op; 671 int req_len; 672 673 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 674 if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) { 675 log(LOG_ERR, "in_arp: runt packet -- m_pullup failed\n"); 676 return; 677 } 678 679 ah = mtod(m, struct arphdr *); 680 op = ntohs(ah->ar_op); 681 memcpy(&isaddr, ar_spa(ah), sizeof isaddr); 682 memcpy(&itaddr, ar_tpa(ah), sizeof itaddr); 683 /* 684 * Check both target and sender IP addresses: 685 * 686 * If we receive the packet on the interface owning the address, 687 * then accept the address. 688 * 689 * For a bridge, we accept the address if the receive interface and 690 * the interface owning the address are on the same bridge. 691 * (This will change slightly when we have clusters of interfaces). 692 */ 693 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) { 694 /* Skip all ia's which don't match */ 695 if (itaddr.s_addr != ia->ia_addr.sin_addr.s_addr) 696 continue; 697 698 if (ia->ia_ifp == ifp) 699 goto match; 700 701 if (ifp->if_bridge && ia->ia_ifp && 702 ifp->if_bridge == ia->ia_ifp->if_bridge) 703 goto match; 704 705 #ifdef CARP 706 /* 707 * If the interface does not match, but the recieving interface 708 * is part of carp, we call carp_iamatch to see if this is a 709 * request for the virtual host ip. 710 * XXX: This is really ugly! 711 */ 712 if (ifp->if_carp != NULL && 713 carp_iamatch(ifp->if_carp, ia, &isaddr, &enaddr) && 714 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) 715 goto match; 716 #endif 717 } 718 LIST_FOREACH(ia, INADDR_HASH(isaddr.s_addr), ia_hash) { 719 /* Skip all ia's which don't match */ 720 if (isaddr.s_addr != ia->ia_addr.sin_addr.s_addr) 721 continue; 722 723 if (ia->ia_ifp == ifp) 724 goto match; 725 726 if (ifp->if_bridge && ia->ia_ifp && 727 ifp->if_bridge == ia->ia_ifp->if_bridge) 728 goto match; 729 } 730 /* 731 * No match, use the first inet address on the receive interface 732 * as a dummy address for the rest of the function. 733 */ 734 TAILQ_FOREACH(ifac, &ifp->if_addrheads[mycpuid], ifa_link) { 735 struct ifaddr *ifa = ifac->ifa; 736 737 if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_INET) { 738 ia = ifatoia(ifa); 739 goto match; 740 } 741 } 742 /* 743 * If we got here, we didn't find any suitable interface, 744 * so drop the packet. 745 */ 746 m_freem(m); 747 return; 748 749 match: 750 if (!enaddr) 751 enaddr = (u_int8_t *)IF_LLADDR(ifp); 752 myaddr = ia->ia_addr.sin_addr; 753 if (!bcmp(ar_sha(ah), enaddr, ifp->if_addrlen)) { 754 m_freem(m); /* it's from me, ignore it. */ 755 return; 756 } 757 if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) { 758 log(LOG_ERR, 759 "arp: link address is broadcast for IP address %s!\n", 760 inet_ntoa(isaddr)); 761 m_freem(m); 762 return; 763 } 764 if (isaddr.s_addr == myaddr.s_addr && myaddr.s_addr != 0) { 765 log(LOG_ERR, 766 "arp: %*D is using my IP address %s!\n", 767 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 768 inet_ntoa(isaddr)); 769 itaddr = myaddr; 770 goto reply; 771 } 772 #ifdef SMP 773 netmsg_init(&msg.netmsg, &curthread->td_msgport, 0, 774 arp_update_msghandler); 775 msg.m = m; 776 msg.saddr = isaddr.s_addr; 777 msg.create = (itaddr.s_addr == myaddr.s_addr); 778 lwkt_domsg(rtable_portfn(0), &msg.netmsg.nm_lmsg, 0); 779 #endif 780 arp_update_oncpu(m, isaddr.s_addr, (itaddr.s_addr == myaddr.s_addr), 781 TRUE); 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), enaddr, ah->ar_hln); 791 } else { 792 struct llinfo_arp *la; 793 794 la = arplookup(itaddr.s_addr, FALSE, SIN_PROXY); 795 if (la == NULL) { 796 struct sockaddr_in sin; 797 798 if (!arp_proxyall) { 799 m_freem(m); 800 return; 801 } 802 803 bzero(&sin, sizeof sin); 804 sin.sin_family = AF_INET; 805 sin.sin_len = sizeof sin; 806 sin.sin_addr = itaddr; 807 808 rt = rtpurelookup((struct sockaddr *)&sin); 809 if (rt == NULL) { 810 m_freem(m); 811 return; 812 } 813 --rt->rt_refcnt; 814 /* 815 * Don't send proxies for nodes on the same interface 816 * as this one came out of, or we'll get into a fight 817 * over who claims what Ether address. 818 */ 819 if (rt->rt_ifp == ifp) { 820 m_freem(m); 821 return; 822 } 823 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 824 memcpy(ar_sha(ah), enaddr, ah->ar_hln); 825 #ifdef DEBUG_PROXY 826 kprintf("arp: proxying for %s\n", inet_ntoa(itaddr)); 827 #endif 828 } else { 829 struct sockaddr_dl *sdl; 830 831 rt = la->la_rt; 832 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 833 sdl = SDL(rt->rt_gateway); 834 memcpy(ar_sha(ah), LLADDR(sdl), ah->ar_hln); 835 } 836 } 837 838 memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln); 839 memcpy(ar_spa(ah), &itaddr, ah->ar_pln); 840 ah->ar_op = htons(ARPOP_REPLY); 841 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 842 switch (ifp->if_type) { 843 case IFT_ETHER: 844 /* 845 * May not be correct for types not explictly 846 * listed, but it is our best guess. 847 */ 848 default: 849 eh = (struct ether_header *)sa.sa_data; 850 memcpy(eh->ether_dhost, ar_tha(ah), sizeof eh->ether_dhost); 851 eh->ether_type = htons(ETHERTYPE_ARP); 852 break; 853 } 854 sa.sa_family = AF_UNSPEC; 855 sa.sa_len = sizeof sa; 856 ifp->if_output(ifp, m, &sa, (struct rtentry *)0); 857 return; 858 } 859 860 #ifdef SMP 861 862 static 863 void 864 arp_update_msghandler(struct netmsg *netmsg) 865 { 866 struct netmsg_arp_update *msg = (struct netmsg_arp_update *)netmsg; 867 int nextcpu; 868 869 arp_update_oncpu(msg->m, msg->saddr, msg->create, FALSE); 870 871 nextcpu = mycpuid + 1; 872 if (nextcpu < ncpus) { 873 lwkt_forwardmsg(rtable_portfn(nextcpu), &msg->netmsg.nm_lmsg); 874 } else { 875 lwkt_replymsg(&msg->netmsg.nm_lmsg, 0); 876 } 877 } 878 879 #endif 880 881 #endif 882 883 /* 884 * Free an arp entry. If the arp entry is actively referenced or represents 885 * a static entry we only clear it back to an unresolved state, otherwise 886 * we destroy the entry entirely. 887 * 888 * Note that static entries are created when route add ... -interface is used 889 * to create an interface route to a (direct) destination. 890 */ 891 static void 892 arptfree(struct llinfo_arp *la) 893 { 894 struct rtentry *rt = la->la_rt; 895 struct sockaddr_dl *sdl; 896 897 if (rt == NULL) 898 panic("arptfree"); 899 sdl = SDL(rt->rt_gateway); 900 if (sdl != NULL && 901 ((rt->rt_refcnt > 0 && sdl->sdl_family == AF_LINK) || 902 (rt->rt_flags & RTF_STATIC))) { 903 sdl->sdl_alen = 0; 904 la->la_preempt = la->la_asked = 0; 905 rt->rt_flags &= ~RTF_REJECT; 906 return; 907 } 908 rtrequest(RTM_DELETE, rt_key(rt), NULL, rt_mask(rt), 0, NULL); 909 } 910 911 /* 912 * Lookup or enter a new address in arptab. 913 */ 914 static struct llinfo_arp * 915 arplookup(in_addr_t addr, boolean_t create, boolean_t proxy) 916 { 917 struct rtentry *rt; 918 struct sockaddr_inarp sin = { sizeof sin, AF_INET }; 919 const char *why = NULL; 920 921 sin.sin_addr.s_addr = addr; 922 sin.sin_other = proxy ? SIN_PROXY : 0; 923 if (create) 924 rt = rtlookup((struct sockaddr *)&sin); 925 else 926 rt = rtpurelookup((struct sockaddr *)&sin); 927 if (rt == NULL) 928 return (NULL); 929 rt->rt_refcnt--; 930 931 if (rt->rt_flags & RTF_GATEWAY) 932 why = "host is not on local network"; 933 else if (!(rt->rt_flags & RTF_LLINFO)) 934 why = "could not allocate llinfo"; 935 else if (rt->rt_gateway->sa_family != AF_LINK) 936 why = "gateway route is not ours"; 937 938 if (why) { 939 if (create) { 940 log(LOG_DEBUG, "arplookup %s failed: %s\n", 941 inet_ntoa(sin.sin_addr), why); 942 } 943 if (rt->rt_refcnt <= 0 && (rt->rt_flags & RTF_WASCLONED)) { 944 /* No references to this route. Purge it. */ 945 rtrequest(RTM_DELETE, rt_key(rt), rt->rt_gateway, 946 rt_mask(rt), rt->rt_flags, NULL); 947 } 948 return (NULL); 949 } 950 return (rt->rt_llinfo); 951 } 952 953 void 954 arp_ifinit(struct ifnet *ifp, struct ifaddr *ifa) 955 { 956 if (IA_SIN(ifa)->sin_addr.s_addr != INADDR_ANY) 957 arprequest(ifp, &IA_SIN(ifa)->sin_addr, &IA_SIN(ifa)->sin_addr, 958 IF_LLADDR(ifp)); 959 ifa->ifa_rtrequest = arp_rtrequest; 960 ifa->ifa_flags |= RTF_CLONING; 961 } 962 963 void 964 arp_ifinit2(struct ifnet *ifp, struct ifaddr *ifa, u_char *enaddr) 965 { 966 if (IA_SIN(ifa)->sin_addr.s_addr != INADDR_ANY) 967 arprequest(ifp, &IA_SIN(ifa)->sin_addr, &IA_SIN(ifa)->sin_addr, 968 enaddr); 969 ifa->ifa_rtrequest = arp_rtrequest; 970 ifa->ifa_flags |= RTF_CLONING; 971 } 972 973 static void 974 arp_init(void) 975 { 976 int cpu; 977 978 for (cpu = 0; cpu < ncpus2; cpu++) 979 LIST_INIT(&llinfo_arp_list[cpu]); 980 netisr_register(NETISR_ARP, cpu0_portfn, arpintr); 981 } 982 983 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0); 984