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 1.42 2007/08/27 16:15:42 hasso 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 /*FALLTHROUGH*/ 232 case RTM_RESOLVE: 233 if (gate->sa_family != AF_LINK || 234 gate->sa_len < sizeof(struct sockaddr_dl)) { 235 log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n"); 236 break; 237 } 238 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 239 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 240 if (la != NULL) 241 break; /* This happens on a route change */ 242 /* 243 * Case 2: This route may come from cloning, or a manual route 244 * add with a LL address. 245 */ 246 R_Malloc(la, struct llinfo_arp *, sizeof *la); 247 rt->rt_llinfo = la; 248 if (la == NULL) { 249 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); 250 break; 251 } 252 bzero(la, sizeof *la); 253 la->la_rt = rt; 254 rt->rt_flags |= RTF_LLINFO; 255 LIST_INSERT_HEAD(&llinfo_arp_list[mycpuid], la, la_le); 256 257 #ifdef INET 258 /* 259 * This keeps the multicast addresses from showing up 260 * in `arp -a' listings as unresolved. It's not actually 261 * functional. Then the same for broadcast. 262 */ 263 if (IN_MULTICAST(ntohl(SIN(rt_key(rt))->sin_addr.s_addr))) { 264 ETHER_MAP_IP_MULTICAST(&SIN(rt_key(rt))->sin_addr, 265 LLADDR(SDL(gate))); 266 SDL(gate)->sdl_alen = 6; 267 rt->rt_expire = 0; 268 } 269 if (in_broadcast(SIN(rt_key(rt))->sin_addr, rt->rt_ifp)) { 270 memcpy(LLADDR(SDL(gate)), rt->rt_ifp->if_broadcastaddr, 271 rt->rt_ifp->if_addrlen); 272 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen; 273 rt->rt_expire = 0; 274 } 275 #endif 276 277 if (SIN(rt_key(rt))->sin_addr.s_addr == 278 (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) { 279 /* 280 * This test used to be 281 * if (loif.if_flags & IFF_UP) 282 * It allowed local traffic to be forced 283 * through the hardware by configuring the 284 * loopback down. However, it causes problems 285 * during network configuration for boards 286 * that can't receive packets they send. It 287 * is now necessary to clear "useloopback" and 288 * remove the route to force traffic out to 289 * the hardware. 290 */ 291 rt->rt_expire = 0; 292 bcopy(IF_LLADDR(rt->rt_ifp), LLADDR(SDL(gate)), 293 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen); 294 if (useloopback) 295 rt->rt_ifp = loif; 296 } 297 break; 298 299 case RTM_DELETE: 300 if (la == NULL) 301 break; 302 LIST_REMOVE(la, la_le); 303 rt->rt_llinfo = NULL; 304 rt->rt_flags &= ~RTF_LLINFO; 305 if (la->la_hold != NULL) 306 m_freem(la->la_hold); 307 Free(la); 308 } 309 } 310 311 /* 312 * Broadcast an ARP request. Caller specifies: 313 * - arp header source ip address 314 * - arp header target ip address 315 * - arp header source ethernet address 316 */ 317 static void 318 arprequest(struct ifnet *ifp, struct in_addr *sip, struct in_addr *tip, 319 u_char *enaddr) 320 { 321 struct mbuf *m; 322 struct ether_header *eh; 323 struct arphdr *ah; 324 struct sockaddr sa; 325 static u_char llcx[] = { 0x82, 0x40, LLC_SNAP_LSAP, LLC_SNAP_LSAP, 326 LLC_UI, 0x00, 0x00, 0x00, 0x08, 0x06 }; 327 u_short ar_hrd; 328 329 if ((m = m_gethdr(MB_DONTWAIT, MT_DATA)) == NULL) 330 return; 331 m->m_pkthdr.rcvif = (struct ifnet *)NULL; 332 333 switch (ifp->if_type) { 334 case IFT_ETHER: 335 /* 336 * This may not be correct for types not explicitly 337 * listed, but this is our best guess 338 */ 339 default: 340 ar_hrd = htons(ARPHRD_ETHER); 341 342 m->m_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 343 m->m_pkthdr.len = m->m_len; 344 MH_ALIGN(m, m->m_len); 345 346 eh = (struct ether_header *)sa.sa_data; 347 /* if_output() will not swap */ 348 eh->ether_type = htons(ETHERTYPE_ARP); 349 memcpy(eh->ether_dhost, ifp->if_broadcastaddr, ifp->if_addrlen); 350 351 ah = mtod(m, struct arphdr *); 352 break; 353 } 354 355 ah->ar_hrd = ar_hrd; 356 ah->ar_pro = htons(ETHERTYPE_IP); 357 ah->ar_hln = ifp->if_addrlen; /* hardware address length */ 358 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 359 ah->ar_op = htons(ARPOP_REQUEST); 360 memcpy(ar_sha(ah), enaddr, ah->ar_hln); 361 memset(ar_tha(ah), 0, ah->ar_hln); 362 memcpy(ar_spa(ah), sip, ah->ar_pln); 363 memcpy(ar_tpa(ah), tip, ah->ar_pln); 364 365 sa.sa_family = AF_UNSPEC; 366 sa.sa_len = sizeof sa; 367 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)NULL); 368 } 369 370 /* 371 * Resolve an IP address into an ethernet address. If success, 372 * desten is filled in. If there is no entry in arptab, 373 * set one up and broadcast a request for the IP address. 374 * Hold onto this mbuf and resend it once the address 375 * is finally resolved. A return value of 1 indicates 376 * that desten has been filled in and the packet should be sent 377 * normally; a 0 return indicates that the packet has been 378 * taken over here, either now or for later transmission. 379 */ 380 int 381 arpresolve( 382 struct ifnet *ifp, 383 struct rtentry *rt0, 384 struct mbuf *m, 385 struct sockaddr *dst, 386 u_char *desten) 387 { 388 struct rtentry *rt; 389 struct llinfo_arp *la = NULL; 390 struct sockaddr_dl *sdl; 391 392 if (m->m_flags & M_BCAST) { /* broadcast */ 393 memcpy(desten, ifp->if_broadcastaddr, ifp->if_addrlen); 394 return (1); 395 } 396 if (m->m_flags & M_MCAST) {/* multicast */ 397 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); 398 return (1); 399 } 400 if (rt0 != NULL) { 401 if (rt_llroute(dst, rt0, &rt) != 0) { 402 m_freem(m); 403 return 0; 404 } 405 la = rt->rt_llinfo; 406 } 407 if (la == NULL) { 408 la = arplookup(SIN(dst)->sin_addr.s_addr, TRUE, FALSE); 409 if (la != NULL) 410 rt = la->la_rt; 411 } 412 if (la == NULL || rt == NULL) { 413 log(LOG_DEBUG, "arpresolve: can't allocate llinfo for %s%s%s\n", 414 inet_ntoa(SIN(dst)->sin_addr), la ? "la" : " ", 415 rt ? "rt" : ""); 416 m_freem(m); 417 return (0); 418 } 419 sdl = SDL(rt->rt_gateway); 420 /* 421 * Check the address family and length is valid, the address 422 * is resolved; otherwise, try to resolve. 423 */ 424 if ((rt->rt_expire == 0 || rt->rt_expire > time_second) && 425 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 426 /* 427 * If entry has an expiry time and it is approaching, 428 * see if we need to send an ARP request within this 429 * arpt_down interval. 430 */ 431 if ((rt->rt_expire != 0) && 432 (time_second + la->la_preempt > rt->rt_expire)) { 433 arprequest(ifp, 434 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 435 &SIN(dst)->sin_addr, 436 IF_LLADDR(ifp)); 437 la->la_preempt--; 438 } 439 440 bcopy(LLADDR(sdl), desten, sdl->sdl_alen); 441 return 1; 442 } 443 /* 444 * If ARP is disabled on this interface, stop. 445 * XXX 446 * Probably should not allocate empty llinfo struct if we are 447 * not going to be sending out an arp request. 448 */ 449 if (ifp->if_flags & IFF_NOARP) { 450 m_freem(m); 451 return (0); 452 } 453 /* 454 * There is an arptab entry, but no ethernet address 455 * response yet. Replace the held mbuf with this 456 * latest one. 457 */ 458 if (la->la_hold != NULL) 459 m_freem(la->la_hold); 460 la->la_hold = m; 461 if (rt->rt_expire || ((rt->rt_flags & RTF_STATIC) && !sdl->sdl_alen)) { 462 rt->rt_flags &= ~RTF_REJECT; 463 if (la->la_asked == 0 || rt->rt_expire != time_second) { 464 rt->rt_expire = time_second; 465 if (la->la_asked++ < arp_maxtries) { 466 arprequest(ifp, 467 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 468 &SIN(dst)->sin_addr, 469 IF_LLADDR(ifp)); 470 } else { 471 rt->rt_flags |= RTF_REJECT; 472 rt->rt_expire += arpt_down; 473 la->la_asked = 0; 474 la->la_preempt = arp_maxtries; 475 } 476 477 } 478 } 479 return (0); 480 } 481 482 /* 483 * Common length and type checks are done here, 484 * then the protocol-specific routine is called. 485 */ 486 static void 487 arpintr(struct netmsg *msg) 488 { 489 struct mbuf *m = ((struct netmsg_packet *)msg)->nm_packet; 490 struct arphdr *ar; 491 u_short ar_hrd; 492 493 if (m->m_len < sizeof(struct arphdr) && 494 ((m = m_pullup(m, sizeof(struct arphdr))) == NULL)) { 495 log(LOG_ERR, "arp: runt packet -- m_pullup failed\n"); 496 goto out2; 497 } 498 ar = mtod(m, struct arphdr *); 499 500 ar_hrd = ntohs(ar->ar_hrd); 501 if (ar_hrd != ARPHRD_ETHER && 502 ar_hrd != ARPHRD_IEEE802) { 503 log(LOG_ERR, 504 "arp: unknown hardware address format (0x%2D)\n", 505 (unsigned char *)&ar->ar_hrd, ""); 506 goto out1; 507 } 508 509 if (m->m_pkthdr.len < arphdr_len(ar) && 510 (m = m_pullup(m, arphdr_len(ar))) == NULL) { 511 log(LOG_ERR, "arp: runt packet\n"); 512 goto out1; 513 } 514 515 switch (ntohs(ar->ar_pro)) { 516 #ifdef INET 517 case ETHERTYPE_IP: 518 in_arpinput(m); 519 goto out2; 520 #endif 521 } 522 out1: 523 m_freem(m); 524 out2: 525 ; 526 /* msg was embedded in the mbuf, do not reply! */ 527 } 528 529 #ifdef INET 530 /* 531 * ARP for Internet protocols on 10 Mb/s Ethernet. 532 * Algorithm is that given in RFC 826. 533 * In addition, a sanity check is performed on the sender 534 * protocol address, to catch impersonators. 535 * We no longer handle negotiations for use of trailer protocol: 536 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 537 * along with IP replies if we wanted trailers sent to us, 538 * and also sent them in response to IP replies. 539 * This allowed either end to announce the desire to receive 540 * trailer packets. 541 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 542 * but formerly didn't normally send requests. 543 */ 544 static int log_arp_wrong_iface = 1; 545 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW, 546 &log_arp_wrong_iface, 0, 547 "log arp packets arriving on the wrong interface"); 548 549 static void 550 arp_update_oncpu(struct mbuf *m, in_addr_t saddr, boolean_t create, 551 boolean_t dologging) 552 { 553 struct arphdr *ah = mtod(m, struct arphdr *); 554 struct ifnet *ifp = m->m_pkthdr.rcvif; 555 struct llinfo_arp *la; 556 struct sockaddr_dl *sdl; 557 struct rtentry *rt; 558 int cpu = mycpuid; 559 560 la = arplookup(saddr, create, FALSE); 561 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { 562 struct in_addr isaddr = { saddr }; 563 564 /* the following is not an error when doing bridging */ 565 if (rt->rt_ifp != ifp) { 566 if (dologging && log_arp_wrong_iface && cpu == 0) { 567 log(LOG_ERR, 568 "arp: %s is on %s " 569 "but got reply from %*D on %s\n", 570 inet_ntoa(isaddr), 571 rt->rt_ifp->if_xname, 572 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 573 ifp->if_xname); 574 } 575 return; 576 } 577 if (sdl->sdl_alen && 578 bcmp(ar_sha(ah), LLADDR(sdl), sdl->sdl_alen)) { 579 if (rt->rt_expire != 0) { 580 if (dologging && cpu == 0) { 581 log(LOG_INFO, 582 "arp: %s moved from %*D to %*D on %s\n", 583 inet_ntoa(isaddr), 584 ifp->if_addrlen, (u_char *)LLADDR(sdl), 585 ":", ifp->if_addrlen, 586 (u_char *)ar_sha(ah), ":", 587 ifp->if_xname); 588 } 589 } else { 590 if (dologging && cpu == 0) { 591 log(LOG_ERR, 592 "arp: %*D attempts to modify permanent entry for %s on %s\n", 593 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 594 inet_ntoa(isaddr), ifp->if_xname); 595 } 596 return; 597 } 598 } 599 /* 600 * sanity check for the address length. 601 * XXX this does not work for protocols with variable address 602 * length. -is 603 */ 604 if (dologging && sdl->sdl_alen && sdl->sdl_alen != ah->ar_hln && 605 cpu == 0) 606 { 607 log(LOG_WARNING, 608 "arp from %*D: new addr len %d, was %d", 609 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 610 ah->ar_hln, sdl->sdl_alen); 611 } 612 if (ifp->if_addrlen != ah->ar_hln) { 613 if (dologging && cpu == 0) { 614 log(LOG_WARNING, 615 "arp from %*D: addr len: new %d, i/f %d (ignored)", 616 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 617 ah->ar_hln, ifp->if_addrlen); 618 } 619 return; 620 } 621 memcpy(LLADDR(sdl), ar_sha(ah), sdl->sdl_alen = ah->ar_hln); 622 if (rt->rt_expire != 0) 623 rt->rt_expire = time_second + arpt_keep; 624 rt->rt_flags &= ~RTF_REJECT; 625 la->la_asked = 0; 626 la->la_preempt = arp_maxtries; 627 628 /* 629 * This particular cpu might have been holding an mbuf 630 * pending ARP resolution. If so, transmit the mbuf now. 631 */ 632 if (la->la_hold != NULL) { 633 m_adj(la->la_hold, sizeof(struct ether_header)); 634 lwkt_serialize_enter(ifp->if_serializer); 635 (*ifp->if_output)(ifp, la->la_hold, rt_key(rt), rt); 636 lwkt_serialize_exit(ifp->if_serializer); 637 la->la_hold = NULL; 638 } 639 } 640 } 641 642 #ifdef SMP 643 644 struct netmsg_arp_update { 645 struct netmsg netmsg; 646 struct mbuf *m; 647 in_addr_t saddr; 648 boolean_t create; 649 }; 650 651 static void arp_update_msghandler(struct netmsg *netmsg); 652 653 #endif 654 655 /* 656 * Called from arpintr() - this routine is run from a single cpu. 657 */ 658 static void 659 in_arpinput(struct mbuf *m) 660 { 661 struct arphdr *ah; 662 struct ifnet *ifp = m->m_pkthdr.rcvif; 663 struct ether_header *eh; 664 struct rtentry *rt; 665 struct ifaddr *ifa; 666 struct in_ifaddr *ia; 667 struct sockaddr sa; 668 struct in_addr isaddr, itaddr, myaddr; 669 #ifdef SMP 670 struct netmsg_arp_update msg; 671 #endif 672 u_int8_t *enaddr = NULL; 673 int op; 674 int req_len; 675 676 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 677 if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) { 678 log(LOG_ERR, "in_arp: runt packet -- m_pullup failed\n"); 679 return; 680 } 681 682 ah = mtod(m, struct arphdr *); 683 op = ntohs(ah->ar_op); 684 memcpy(&isaddr, ar_spa(ah), sizeof isaddr); 685 memcpy(&itaddr, ar_tpa(ah), sizeof itaddr); 686 /* 687 * Check both target and sender IP addresses: 688 * 689 * If we receive the packet on the interface owning the address, 690 * then accept the address. 691 * 692 * For a bridge, we accept the address if the receive interface and 693 * the interface owning the address are on the same bridge. 694 * (This will change slightly when we have clusters of interfaces). 695 */ 696 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) { 697 /* Skip all ia's which don't match */ 698 if (itaddr.s_addr != ia->ia_addr.sin_addr.s_addr) 699 continue; 700 701 if (ia->ia_ifp == ifp) 702 goto match; 703 704 if (ifp->if_bridge && ia->ia_ifp && 705 ifp->if_bridge == ia->ia_ifp->if_bridge) 706 goto match; 707 708 #ifdef CARP 709 /* 710 * If the interface does not match, but the recieving interface 711 * is part of carp, we call carp_iamatch to see if this is a 712 * request for the virtual host ip. 713 * XXX: This is really ugly! 714 */ 715 if (ifp->if_carp != NULL && 716 carp_iamatch(ifp->if_carp, ia, &isaddr, &enaddr) && 717 itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) 718 goto match; 719 #endif 720 } 721 LIST_FOREACH(ia, INADDR_HASH(isaddr.s_addr), ia_hash) { 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(ifa, &ifp->if_addrhead, ifa_link) { 738 if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_INET) { 739 ia = ifatoia(ifa); 740 goto match; 741 } 742 } 743 /* 744 * If we got here, we didn't find any suitable interface, 745 * so drop the packet. 746 */ 747 m_freem(m); 748 return; 749 750 match: 751 if (!enaddr) 752 enaddr = (u_int8_t *)IF_LLADDR(ifp); 753 myaddr = ia->ia_addr.sin_addr; 754 if (!bcmp(ar_sha(ah), enaddr, ifp->if_addrlen)) { 755 m_freem(m); /* it's from me, ignore it. */ 756 return; 757 } 758 if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) { 759 log(LOG_ERR, 760 "arp: link address is broadcast for IP address %s!\n", 761 inet_ntoa(isaddr)); 762 m_freem(m); 763 return; 764 } 765 if (isaddr.s_addr == myaddr.s_addr && myaddr.s_addr != 0) { 766 log(LOG_ERR, 767 "arp: %*D is using my IP address %s!\n", 768 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 769 inet_ntoa(isaddr)); 770 itaddr = myaddr; 771 goto reply; 772 } 773 #ifdef SMP 774 netmsg_init(&msg.netmsg, &curthread->td_msgport, 0, 775 arp_update_msghandler); 776 msg.m = m; 777 msg.saddr = isaddr.s_addr; 778 msg.create = (itaddr.s_addr == myaddr.s_addr); 779 lwkt_domsg(rtable_portfn(0), &msg.netmsg.nm_lmsg, 0); 780 #endif 781 arp_update_oncpu(m, isaddr.s_addr, (itaddr.s_addr == myaddr.s_addr), 782 TRUE); 783 reply: 784 if (op != ARPOP_REQUEST) { 785 m_freem(m); 786 return; 787 } 788 if (itaddr.s_addr == myaddr.s_addr) { 789 /* I am the target */ 790 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 791 memcpy(ar_sha(ah), enaddr, ah->ar_hln); 792 } else { 793 struct llinfo_arp *la; 794 795 la = arplookup(itaddr.s_addr, FALSE, SIN_PROXY); 796 if (la == NULL) { 797 struct sockaddr_in sin; 798 799 if (!arp_proxyall) { 800 m_freem(m); 801 return; 802 } 803 804 bzero(&sin, sizeof sin); 805 sin.sin_family = AF_INET; 806 sin.sin_len = sizeof sin; 807 sin.sin_addr = itaddr; 808 809 rt = rtpurelookup((struct sockaddr *)&sin); 810 if (rt == NULL) { 811 m_freem(m); 812 return; 813 } 814 --rt->rt_refcnt; 815 /* 816 * Don't send proxies for nodes on the same interface 817 * as this one came out of, or we'll get into a fight 818 * over who claims what Ether address. 819 */ 820 if (rt->rt_ifp == ifp) { 821 m_freem(m); 822 return; 823 } 824 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 825 memcpy(ar_sha(ah), enaddr, ah->ar_hln); 826 #ifdef DEBUG_PROXY 827 kprintf("arp: proxying for %s\n", inet_ntoa(itaddr)); 828 #endif 829 } else { 830 struct sockaddr_dl *sdl; 831 832 rt = la->la_rt; 833 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 834 sdl = SDL(rt->rt_gateway); 835 memcpy(ar_sha(ah), LLADDR(sdl), ah->ar_hln); 836 } 837 } 838 839 memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln); 840 memcpy(ar_spa(ah), &itaddr, ah->ar_pln); 841 ah->ar_op = htons(ARPOP_REPLY); 842 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 843 switch (ifp->if_type) { 844 case IFT_ETHER: 845 /* 846 * May not be correct for types not explictly 847 * listed, but it is our best guess. 848 */ 849 default: 850 eh = (struct ether_header *)sa.sa_data; 851 memcpy(eh->ether_dhost, ar_tha(ah), sizeof eh->ether_dhost); 852 eh->ether_type = htons(ETHERTYPE_ARP); 853 break; 854 } 855 sa.sa_family = AF_UNSPEC; 856 sa.sa_len = sizeof sa; 857 lwkt_serialize_enter(ifp->if_serializer); 858 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 859 lwkt_serialize_exit(ifp->if_serializer); 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 if (IA_SIN(ifa)->sin_addr.s_addr != INADDR_ANY) 960 arprequest(ifp, &IA_SIN(ifa)->sin_addr, &IA_SIN(ifa)->sin_addr, 961 IF_LLADDR(ifp)); 962 ifa->ifa_rtrequest = arp_rtrequest; 963 ifa->ifa_flags |= RTF_CLONING; 964 } 965 966 void 967 arp_ifinit2(struct ifnet *ifp, struct ifaddr *ifa, u_char *enaddr) 968 { 969 if (IA_SIN(ifa)->sin_addr.s_addr != INADDR_ANY) 970 arprequest(ifp, &IA_SIN(ifa)->sin_addr, &IA_SIN(ifa)->sin_addr, 971 enaddr); 972 ifa->ifa_rtrequest = arp_rtrequest; 973 ifa->ifa_flags |= RTF_CLONING; 974 } 975 976 static void 977 arp_init(void) 978 { 979 int cpu; 980 981 for (cpu = 0; cpu < ncpus2; cpu++) 982 LIST_INIT(&llinfo_arp_list[cpu]); 983 netisr_register(NETISR_ARP, cpu0_portfn, arpintr); 984 } 985 986 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0); 987