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 1.36 2007/03/04 18:51:59 swildner 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 78 #include <sys/param.h> 79 #include <sys/kernel.h> 80 #include <sys/queue.h> 81 #include <sys/sysctl.h> 82 #include <sys/systm.h> 83 #include <sys/mbuf.h> 84 #include <sys/malloc.h> 85 #include <sys/socket.h> 86 #include <sys/syslog.h> 87 88 #include <sys/thread2.h> 89 #include <sys/msgport2.h> 90 91 #include <net/if.h> 92 #include <net/if_dl.h> 93 #include <net/if_types.h> 94 #include <net/route.h> 95 #include <net/netisr.h> 96 #include <net/if_llc.h> 97 98 #include <netinet/in.h> 99 #include <netinet/in_var.h> 100 #include <netinet/if_ether.h> 101 102 #include <net/if_arc.h> 103 #include <net/iso88025.h> 104 105 #define SIN(s) ((struct sockaddr_in *)s) 106 #define SDL(s) ((struct sockaddr_dl *)s) 107 108 SYSCTL_DECL(_net_link_ether); 109 SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, ""); 110 111 /* timer values */ 112 static int arpt_prune = (5*60*1); /* walk list every 5 minutes */ 113 static int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */ 114 static int arpt_down = 20; /* once declared down, don't send for 20 sec */ 115 116 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, prune_intvl, CTLFLAG_RW, 117 &arpt_prune, 0, ""); 118 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW, 119 &arpt_keep, 0, ""); 120 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, host_down_time, CTLFLAG_RW, 121 &arpt_down, 0, ""); 122 123 #define rt_expire rt_rmx.rmx_expire 124 125 struct llinfo_arp { 126 LIST_ENTRY(llinfo_arp) la_le; 127 struct rtentry *la_rt; 128 struct mbuf *la_hold; /* last packet until resolved/timeout */ 129 u_short la_preempt; /* countdown for pre-expiry arps */ 130 u_short la_asked; /* #times we QUERIED following expiration */ 131 }; 132 133 static LIST_HEAD(, llinfo_arp) llinfo_arp_list[MAXCPU]; 134 135 static int arp_maxtries = 5; 136 static int useloopback = 1; /* use loopback interface for local traffic */ 137 static int arp_proxyall = 0; 138 139 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW, 140 &arp_maxtries, 0, ""); 141 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW, 142 &useloopback, 0, ""); 143 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW, 144 &arp_proxyall, 0, ""); 145 146 static void arp_rtrequest (int, struct rtentry *, struct rt_addrinfo *); 147 static void arprequest (struct ifnet *, 148 struct in_addr *, struct in_addr *, u_char *); 149 static int arpintr(struct netmsg *); 150 static void arptfree (struct llinfo_arp *); 151 static void arptimer (void *); 152 static struct llinfo_arp 153 *arplookup (in_addr_t addr, boolean_t create, boolean_t proxy); 154 #ifdef INET 155 static void in_arpinput (struct mbuf *); 156 #endif 157 158 static struct callout arptimer_ch[MAXCPU]; 159 160 /* 161 * Timeout routine. Age arp_tab entries periodically. 162 */ 163 /* ARGSUSED */ 164 static void 165 arptimer(void *ignored_arg) 166 { 167 struct llinfo_arp *la, *nla; 168 169 crit_enter(); 170 LIST_FOREACH_MUTABLE(la, &llinfo_arp_list[mycpuid], la_le, nla) { 171 if (la->la_rt->rt_expire && la->la_rt->rt_expire <= time_second) 172 arptfree(la); 173 } 174 callout_reset(&arptimer_ch[mycpuid], arpt_prune * hz, arptimer, NULL); 175 crit_exit(); 176 } 177 178 /* 179 * Parallel to llc_rtrequest. 180 */ 181 static void 182 arp_rtrequest(int req, struct rtentry *rt, struct rt_addrinfo *info) 183 { 184 struct sockaddr *gate = rt->rt_gateway; 185 struct llinfo_arp *la = rt->rt_llinfo; 186 187 struct sockaddr_dl null_sdl = { sizeof null_sdl, AF_LINK }; 188 static boolean_t arpinit_done[MAXCPU]; 189 190 if (!arpinit_done[mycpuid]) { 191 arpinit_done[mycpuid] = TRUE; 192 callout_init(&arptimer_ch[mycpuid]); 193 callout_reset(&arptimer_ch[mycpuid], hz, arptimer, NULL); 194 } 195 if (rt->rt_flags & RTF_GATEWAY) 196 return; 197 198 switch (req) { 199 case RTM_ADD: 200 /* 201 * XXX: If this is a manually added route to interface 202 * such as older version of routed or gated might provide, 203 * restore cloning bit. 204 */ 205 if (!(rt->rt_flags & RTF_HOST) && 206 SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff) 207 rt->rt_flags |= RTF_CLONING; 208 if (rt->rt_flags & RTF_CLONING) { 209 /* 210 * Case 1: This route should come from a route to iface. 211 */ 212 rt_setgate(rt, rt_key(rt), 213 (struct sockaddr *)&null_sdl); 214 gate = rt->rt_gateway; 215 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 216 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 217 rt->rt_expire = time_second; 218 break; 219 } 220 /* Announce a new entry if requested. */ 221 if (rt->rt_flags & RTF_ANNOUNCE) 222 arprequest(rt->rt_ifp, 223 &SIN(rt_key(rt))->sin_addr, 224 &SIN(rt_key(rt))->sin_addr, 225 LLADDR(SDL(gate))); 226 /*FALLTHROUGH*/ 227 case RTM_RESOLVE: 228 if (gate->sa_family != AF_LINK || 229 gate->sa_len < sizeof(struct sockaddr_dl)) { 230 log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n"); 231 break; 232 } 233 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 234 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 235 if (la != NULL) 236 break; /* This happens on a route change */ 237 /* 238 * Case 2: This route may come from cloning, or a manual route 239 * add with a LL address. 240 */ 241 R_Malloc(la, struct llinfo_arp *, sizeof *la); 242 rt->rt_llinfo = la; 243 if (la == NULL) { 244 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); 245 break; 246 } 247 bzero(la, sizeof *la); 248 la->la_rt = rt; 249 rt->rt_flags |= RTF_LLINFO; 250 LIST_INSERT_HEAD(&llinfo_arp_list[mycpuid], la, la_le); 251 252 #ifdef INET 253 /* 254 * This keeps the multicast addresses from showing up 255 * in `arp -a' listings as unresolved. It's not actually 256 * functional. Then the same for broadcast. 257 */ 258 if (IN_MULTICAST(ntohl(SIN(rt_key(rt))->sin_addr.s_addr)) && 259 rt->rt_ifp->if_type != IFT_ARCNET) { 260 ETHER_MAP_IP_MULTICAST(&SIN(rt_key(rt))->sin_addr, 261 LLADDR(SDL(gate))); 262 SDL(gate)->sdl_alen = 6; 263 rt->rt_expire = 0; 264 } 265 if (in_broadcast(SIN(rt_key(rt))->sin_addr, rt->rt_ifp)) { 266 memcpy(LLADDR(SDL(gate)), rt->rt_ifp->if_broadcastaddr, 267 rt->rt_ifp->if_addrlen); 268 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen; 269 rt->rt_expire = 0; 270 } 271 #endif 272 273 if (SIN(rt_key(rt))->sin_addr.s_addr == 274 (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) { 275 /* 276 * This test used to be 277 * if (loif.if_flags & IFF_UP) 278 * It allowed local traffic to be forced 279 * through the hardware by configuring the 280 * loopback down. However, it causes problems 281 * during network configuration for boards 282 * that can't receive packets they send. It 283 * is now necessary to clear "useloopback" and 284 * remove the route to force traffic out to 285 * the hardware. 286 */ 287 rt->rt_expire = 0; 288 bcopy(IF_LLADDR(rt->rt_ifp), LLADDR(SDL(gate)), 289 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen); 290 if (useloopback) 291 rt->rt_ifp = loif; 292 } 293 break; 294 295 case RTM_DELETE: 296 if (la == NULL) 297 break; 298 LIST_REMOVE(la, la_le); 299 rt->rt_llinfo = NULL; 300 rt->rt_flags &= ~RTF_LLINFO; 301 if (la->la_hold != NULL) 302 m_freem(la->la_hold); 303 Free(la); 304 } 305 } 306 307 /* 308 * Broadcast an ARP request. Caller specifies: 309 * - arp header source ip address 310 * - arp header target ip address 311 * - arp header source ethernet address 312 */ 313 static void 314 arprequest(struct ifnet *ifp, struct in_addr *sip, struct in_addr *tip, 315 u_char *enaddr) 316 { 317 struct mbuf *m; 318 struct ether_header *eh; 319 struct arc_header *arh; 320 struct arphdr *ah; 321 struct sockaddr sa; 322 static u_char llcx[] = { 0x82, 0x40, LLC_SNAP_LSAP, LLC_SNAP_LSAP, 323 LLC_UI, 0x00, 0x00, 0x00, 0x08, 0x06 }; 324 u_short ar_hrd; 325 326 if ((m = m_gethdr(MB_DONTWAIT, MT_DATA)) == NULL) 327 return; 328 m->m_pkthdr.rcvif = (struct ifnet *)NULL; 329 330 switch (ifp->if_type) { 331 case IFT_ARCNET: 332 ar_hrd = htons(ARPHRD_ARCNET); 333 334 m->m_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 335 m->m_pkthdr.len = m->m_len; 336 MH_ALIGN(m, m->m_len); 337 338 arh = (struct arc_header *)sa.sa_data; 339 arh->arc_dhost = ifp->if_broadcastaddr[0]; 340 arh->arc_type = ARCTYPE_ARP; 341 342 ah = mtod(m, struct arphdr *); 343 break; 344 345 case IFT_ISO88025: 346 ar_hrd = htons(ARPHRD_IEEE802); 347 348 m->m_len = (sizeof llcx) + 349 arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 350 m->m_pkthdr.len = m->m_len; 351 MH_ALIGN(m, m->m_len); 352 353 memcpy(mtod(m, caddr_t), llcx, sizeof llcx); 354 memcpy(sa.sa_data, ifp->if_broadcastaddr, ifp->if_addrlen); 355 memcpy(sa.sa_data + 6, enaddr, 6); 356 sa.sa_data[6] |= TR_RII; 357 sa.sa_data[12] = TR_AC; 358 sa.sa_data[13] = TR_LLC_FRAME; 359 360 ah = (struct arphdr *)(mtod(m, char *) + sizeof llcx); 361 break; 362 case IFT_FDDI: 363 case IFT_ETHER: 364 /* 365 * This may not be correct for types not explicitly 366 * listed, but this is our best guess 367 */ 368 default: 369 ar_hrd = htons(ARPHRD_ETHER); 370 371 m->m_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 372 m->m_pkthdr.len = m->m_len; 373 MH_ALIGN(m, m->m_len); 374 375 eh = (struct ether_header *)sa.sa_data; 376 /* if_output() will not swap */ 377 eh->ether_type = htons(ETHERTYPE_ARP); 378 memcpy(eh->ether_dhost, ifp->if_broadcastaddr, ifp->if_addrlen); 379 380 ah = mtod(m, struct arphdr *); 381 break; 382 } 383 384 ah->ar_hrd = ar_hrd; 385 ah->ar_pro = htons(ETHERTYPE_IP); 386 ah->ar_hln = ifp->if_addrlen; /* hardware address length */ 387 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 388 ah->ar_op = htons(ARPOP_REQUEST); 389 memcpy(ar_sha(ah), enaddr, ah->ar_hln); 390 memset(ar_tha(ah), 0, ah->ar_hln); 391 memcpy(ar_spa(ah), sip, ah->ar_pln); 392 memcpy(ar_tpa(ah), tip, ah->ar_pln); 393 394 sa.sa_family = AF_UNSPEC; 395 sa.sa_len = sizeof sa; 396 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)NULL); 397 } 398 399 /* 400 * Resolve an IP address into an ethernet address. If success, 401 * desten is filled in. If there is no entry in arptab, 402 * set one up and broadcast a request for the IP address. 403 * Hold onto this mbuf and resend it once the address 404 * is finally resolved. A return value of 1 indicates 405 * that desten has been filled in and the packet should be sent 406 * normally; a 0 return indicates that the packet has been 407 * taken over here, either now or for later transmission. 408 */ 409 int 410 arpresolve( 411 struct ifnet *ifp, 412 struct rtentry *rt0, 413 struct mbuf *m, 414 struct sockaddr *dst, 415 u_char *desten) 416 { 417 struct rtentry *rt; 418 struct llinfo_arp *la = NULL; 419 struct sockaddr_dl *sdl; 420 421 if (m->m_flags & M_BCAST) { /* broadcast */ 422 memcpy(desten, ifp->if_broadcastaddr, ifp->if_addrlen); 423 return (1); 424 } 425 if (m->m_flags & M_MCAST && ifp->if_type != IFT_ARCNET) {/* multicast */ 426 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); 427 return (1); 428 } 429 if (rt0 != NULL) { 430 if (rt_llroute(dst, rt0, &rt) != 0) { 431 m_freem(m); 432 return 0; 433 } 434 la = rt->rt_llinfo; 435 } 436 if (la == NULL) { 437 la = arplookup(SIN(dst)->sin_addr.s_addr, TRUE, FALSE); 438 if (la != NULL) 439 rt = la->la_rt; 440 } 441 if (la == NULL || rt == NULL) { 442 log(LOG_DEBUG, "arpresolve: can't allocate llinfo for %s%s%s\n", 443 inet_ntoa(SIN(dst)->sin_addr), la ? "la" : " ", 444 rt ? "rt" : ""); 445 m_freem(m); 446 return (0); 447 } 448 sdl = SDL(rt->rt_gateway); 449 /* 450 * Check the address family and length is valid, the address 451 * is resolved; otherwise, try to resolve. 452 */ 453 if ((rt->rt_expire == 0 || rt->rt_expire > time_second) && 454 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 455 /* 456 * If entry has an expiry time and it is approaching, 457 * see if we need to send an ARP request within this 458 * arpt_down interval. 459 */ 460 if ((rt->rt_expire != 0) && 461 (time_second + la->la_preempt > rt->rt_expire)) { 462 arprequest(ifp, 463 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 464 &SIN(dst)->sin_addr, 465 IF_LLADDR(ifp)); 466 la->la_preempt--; 467 } 468 469 bcopy(LLADDR(sdl), desten, sdl->sdl_alen); 470 return 1; 471 } 472 /* 473 * If ARP is disabled on this interface, stop. 474 * XXX 475 * Probably should not allocate empty llinfo struct if we are 476 * not going to be sending out an arp request. 477 */ 478 if (ifp->if_flags & IFF_NOARP) { 479 m_freem(m); 480 return (0); 481 } 482 /* 483 * There is an arptab entry, but no ethernet address 484 * response yet. Replace the held mbuf with this 485 * latest one. 486 */ 487 if (la->la_hold != NULL) 488 m_freem(la->la_hold); 489 la->la_hold = m; 490 if (rt->rt_expire || ((rt->rt_flags & RTF_STATIC) && !sdl->sdl_alen)) { 491 rt->rt_flags &= ~RTF_REJECT; 492 if (la->la_asked == 0 || rt->rt_expire != time_second) { 493 rt->rt_expire = time_second; 494 if (la->la_asked++ < arp_maxtries) { 495 arprequest(ifp, 496 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 497 &SIN(dst)->sin_addr, 498 IF_LLADDR(ifp)); 499 } else { 500 rt->rt_flags |= RTF_REJECT; 501 rt->rt_expire += arpt_down; 502 la->la_asked = 0; 503 la->la_preempt = arp_maxtries; 504 } 505 506 } 507 } 508 return (0); 509 } 510 511 /* 512 * Common length and type checks are done here, 513 * then the protocol-specific routine is called. 514 */ 515 static int 516 arpintr(struct netmsg *msg) 517 { 518 struct mbuf *m = ((struct netmsg_packet *)msg)->nm_packet; 519 struct arphdr *ar; 520 u_short ar_hrd; 521 522 if (m->m_len < sizeof(struct arphdr) && 523 ((m = m_pullup(m, sizeof(struct arphdr))) == NULL)) { 524 log(LOG_ERR, "arp: runt packet -- m_pullup failed\n"); 525 goto out2; 526 } 527 ar = mtod(m, struct arphdr *); 528 529 ar_hrd = ntohs(ar->ar_hrd); 530 if (ar_hrd != ARPHRD_ETHER && 531 ar_hrd != ARPHRD_IEEE802 && 532 ar_hrd != ARPHRD_ARCNET) { 533 log(LOG_ERR, 534 "arp: unknown hardware address format (0x%2D)\n", 535 (unsigned char *)&ar->ar_hrd, ""); 536 goto out1; 537 } 538 539 if (m->m_pkthdr.len < arphdr_len(ar) && 540 (m = m_pullup(m, arphdr_len(ar))) == NULL) { 541 log(LOG_ERR, "arp: runt packet\n"); 542 goto out1; 543 } 544 545 switch (ntohs(ar->ar_pro)) { 546 #ifdef INET 547 case ETHERTYPE_IP: 548 in_arpinput(m); 549 goto out2; 550 #endif 551 } 552 out1: 553 m_freem(m); 554 out2: 555 /* msg was embedded in the mbuf, do not reply! */ 556 return(EASYNC); 557 } 558 559 #ifdef INET 560 /* 561 * ARP for Internet protocols on 10 Mb/s Ethernet. 562 * Algorithm is that given in RFC 826. 563 * In addition, a sanity check is performed on the sender 564 * protocol address, to catch impersonators. 565 * We no longer handle negotiations for use of trailer protocol: 566 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 567 * along with IP replies if we wanted trailers sent to us, 568 * and also sent them in response to IP replies. 569 * This allowed either end to announce the desire to receive 570 * trailer packets. 571 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 572 * but formerly didn't normally send requests. 573 */ 574 static int log_arp_wrong_iface = 1; 575 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW, 576 &log_arp_wrong_iface, 0, 577 "log arp packets arriving on the wrong interface"); 578 579 static void 580 arp_update_oncpu(struct mbuf *m, in_addr_t saddr, boolean_t create, 581 boolean_t dologging) 582 { 583 struct arphdr *ah = mtod(m, struct arphdr *); 584 struct ifnet *ifp = m->m_pkthdr.rcvif; 585 struct llinfo_arp *la; 586 struct sockaddr_dl *sdl; 587 struct rtentry *rt; 588 int cpu = mycpuid; 589 590 la = arplookup(saddr, create, FALSE); 591 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { 592 struct in_addr isaddr = { saddr }; 593 594 /* the following is not an error when doing bridging */ 595 if (rt->rt_ifp != ifp) { 596 if (dologging && log_arp_wrong_iface && cpu == 0) { 597 log(LOG_ERR, 598 "arp: %s is on %s " 599 "but got reply from %*D on %s\n", 600 inet_ntoa(isaddr), 601 rt->rt_ifp->if_xname, 602 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 603 ifp->if_xname); 604 } 605 return; 606 } 607 if (sdl->sdl_alen && 608 bcmp(ar_sha(ah), LLADDR(sdl), sdl->sdl_alen)) { 609 if (rt->rt_expire != 0) { 610 if (dologging && cpu == 0) { 611 log(LOG_INFO, 612 "arp: %s moved from %*D to %*D on %s\n", 613 inet_ntoa(isaddr), 614 ifp->if_addrlen, (u_char *)LLADDR(sdl), 615 ":", ifp->if_addrlen, 616 (u_char *)ar_sha(ah), ":", 617 ifp->if_xname); 618 } 619 } else { 620 if (dologging && cpu == 0) { 621 log(LOG_ERR, 622 "arp: %*D attempts to modify permanent entry for %s on %s\n", 623 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 624 inet_ntoa(isaddr), ifp->if_xname); 625 } 626 return; 627 } 628 } 629 /* 630 * sanity check for the address length. 631 * XXX this does not work for protocols with variable address 632 * length. -is 633 */ 634 if (dologging && sdl->sdl_alen && sdl->sdl_alen != ah->ar_hln && 635 cpu == 0) 636 { 637 log(LOG_WARNING, 638 "arp from %*D: new addr len %d, was %d", 639 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 640 ah->ar_hln, sdl->sdl_alen); 641 } 642 if (ifp->if_addrlen != ah->ar_hln) { 643 if (dologging && cpu == 0) { 644 log(LOG_WARNING, 645 "arp from %*D: addr len: new %d, i/f %d (ignored)", 646 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 647 ah->ar_hln, ifp->if_addrlen); 648 } 649 return; 650 } 651 memcpy(LLADDR(sdl), ar_sha(ah), sdl->sdl_alen = ah->ar_hln); 652 /* 653 * If we receive an arp from a token-ring station over 654 * a token-ring nic then try to save the source 655 * routing info. 656 */ 657 if (ifp->if_type == IFT_ISO88025) { 658 struct iso88025_header *th = 659 (struct iso88025_header *)m->m_pkthdr.header; 660 struct iso88025_sockaddr_dl_data *trld = 661 SDL_ISO88025(sdl); 662 int rif_len; 663 664 rif_len = TR_RCF_RIFLEN(th->rcf); 665 if ((th->iso88025_shost[0] & TR_RII) && 666 (rif_len > 2)) { 667 trld->trld_rcf = th->rcf; 668 trld->trld_rcf ^= htons(TR_RCF_DIR); 669 memcpy(trld->trld_route, th->rd, rif_len - 2); 670 trld->trld_rcf &= ~htons(TR_RCF_BCST_MASK); 671 /* 672 * Set up source routing information for 673 * reply packet (XXX) 674 */ 675 m->m_data -= rif_len; 676 m->m_len += rif_len; 677 m->m_pkthdr.len += rif_len; 678 } else { 679 th->iso88025_shost[0] &= ~TR_RII; 680 trld->trld_rcf = 0; 681 } 682 m->m_data -= 8; 683 m->m_len += 8; 684 m->m_pkthdr.len += 8; 685 th->rcf = trld->trld_rcf; 686 } 687 if (rt->rt_expire != 0) 688 rt->rt_expire = time_second + arpt_keep; 689 rt->rt_flags &= ~RTF_REJECT; 690 la->la_asked = 0; 691 la->la_preempt = arp_maxtries; 692 693 /* 694 * This particular cpu might have been holding an mbuf 695 * pending ARP resolution. If so, transmit the mbuf now. 696 */ 697 if (la->la_hold != NULL) { 698 m_adj(la->la_hold, sizeof(struct ether_header)); 699 lwkt_serialize_enter(ifp->if_serializer); 700 (*ifp->if_output)(ifp, la->la_hold, rt_key(rt), rt); 701 lwkt_serialize_exit(ifp->if_serializer); 702 la->la_hold = NULL; 703 } 704 } 705 } 706 707 #ifdef SMP 708 709 struct netmsg_arp_update { 710 struct lwkt_msg lmsg; 711 struct mbuf *m; 712 in_addr_t saddr; 713 boolean_t create; 714 }; 715 716 static int arp_update_msghandler(struct lwkt_msg *lmsg); 717 718 #endif 719 720 /* 721 * Called from arpintr() - this routine is run from a single cpu. 722 */ 723 static void 724 in_arpinput(struct mbuf *m) 725 { 726 struct arphdr *ah; 727 struct ifnet *ifp = m->m_pkthdr.rcvif; 728 struct ether_header *eh; 729 struct arc_header *arh; 730 struct iso88025_header *th = (struct iso88025_header *)NULL; 731 struct rtentry *rt; 732 struct ifaddr *ifa; 733 struct in_ifaddr *ia; 734 struct sockaddr sa; 735 struct in_addr isaddr, itaddr, myaddr; 736 #ifdef SMP 737 struct netmsg_arp_update msg; 738 #endif 739 int op; 740 int req_len; 741 742 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 743 if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) { 744 log(LOG_ERR, "in_arp: runt packet -- m_pullup failed\n"); 745 return; 746 } 747 748 ah = mtod(m, struct arphdr *); 749 op = ntohs(ah->ar_op); 750 memcpy(&isaddr, ar_spa(ah), sizeof isaddr); 751 memcpy(&itaddr, ar_tpa(ah), sizeof itaddr); 752 /* 753 * Check both target and sender IP addresses: 754 * 755 * If we receive the packet on the interface owning the address, 756 * then accept the address. 757 * 758 * For a bridge, we accept the address if the receive interface and 759 * the interface owning the address are on the same bridge. 760 * (This will change slightly when we have clusters of interfaces). 761 */ 762 LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) { 763 /* Skip all ia's which don't match */ 764 if (itaddr.s_addr != ia->ia_addr.sin_addr.s_addr) 765 continue; 766 767 if (ia->ia_ifp == ifp) 768 goto match; 769 770 if (ifp->if_bridge && ia->ia_ifp && 771 ifp->if_bridge == ia->ia_ifp->if_bridge) 772 goto match; 773 } 774 LIST_FOREACH(ia, INADDR_HASH(isaddr.s_addr), ia_hash) { 775 /* Skip all ia's which don't match */ 776 if (isaddr.s_addr != ia->ia_addr.sin_addr.s_addr) 777 continue; 778 779 if (ia->ia_ifp == ifp) 780 goto match; 781 782 if (ifp->if_bridge && ia->ia_ifp && 783 ifp->if_bridge == ia->ia_ifp->if_bridge) 784 goto match; 785 } 786 /* 787 * No match, use the first inet address on the receive interface 788 * as a dummy address for the rest of the function. 789 */ 790 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) { 791 if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_INET) { 792 ia = ifatoia(ifa); 793 goto match; 794 } 795 } 796 /* 797 * If we got here, we didn't find any suitable interface, 798 * so drop the packet. 799 */ 800 m_freem(m); 801 return; 802 803 match: 804 myaddr = ia->ia_addr.sin_addr; 805 if (!bcmp(ar_sha(ah), IF_LLADDR(ifp), ifp->if_addrlen)) { 806 m_freem(m); /* it's from me, ignore it. */ 807 return; 808 } 809 if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) { 810 log(LOG_ERR, 811 "arp: link address is broadcast for IP address %s!\n", 812 inet_ntoa(isaddr)); 813 m_freem(m); 814 return; 815 } 816 if (isaddr.s_addr == myaddr.s_addr && myaddr.s_addr != 0) { 817 log(LOG_ERR, 818 "arp: %*D is using my IP address %s!\n", 819 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 820 inet_ntoa(isaddr)); 821 itaddr = myaddr; 822 goto reply; 823 } 824 #ifdef SMP 825 lwkt_initmsg(&msg.lmsg, &curthread->td_msgport, 0, 826 lwkt_cmd_func(arp_update_msghandler), lwkt_cmd_op_none); 827 msg.m = m; 828 msg.saddr = isaddr.s_addr; 829 msg.create = (itaddr.s_addr == myaddr.s_addr); 830 lwkt_domsg(rtable_portfn(0), &msg.lmsg); 831 #endif 832 arp_update_oncpu(m, isaddr.s_addr, (itaddr.s_addr == myaddr.s_addr), 833 TRUE); 834 reply: 835 if (op != ARPOP_REQUEST) { 836 m_freem(m); 837 return; 838 } 839 if (itaddr.s_addr == myaddr.s_addr) { 840 /* I am the target */ 841 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 842 memcpy(ar_sha(ah), IF_LLADDR(ifp), ah->ar_hln); 843 } else { 844 struct llinfo_arp *la; 845 846 la = arplookup(itaddr.s_addr, FALSE, SIN_PROXY); 847 if (la == NULL) { 848 struct sockaddr_in sin; 849 850 if (!arp_proxyall) { 851 m_freem(m); 852 return; 853 } 854 855 bzero(&sin, sizeof sin); 856 sin.sin_family = AF_INET; 857 sin.sin_len = sizeof sin; 858 sin.sin_addr = itaddr; 859 860 rt = rtpurelookup((struct sockaddr *)&sin); 861 if (rt == NULL) { 862 m_freem(m); 863 return; 864 } 865 --rt->rt_refcnt; 866 /* 867 * Don't send proxies for nodes on the same interface 868 * as this one came out of, or we'll get into a fight 869 * over who claims what Ether address. 870 */ 871 if (rt->rt_ifp == ifp) { 872 m_freem(m); 873 return; 874 } 875 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 876 memcpy(ar_sha(ah), IF_LLADDR(ifp), ah->ar_hln); 877 #ifdef DEBUG_PROXY 878 kprintf("arp: proxying for %s\n", inet_ntoa(itaddr)); 879 #endif 880 } else { 881 struct sockaddr_dl *sdl; 882 883 rt = la->la_rt; 884 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 885 sdl = SDL(rt->rt_gateway); 886 memcpy(ar_sha(ah), LLADDR(sdl), ah->ar_hln); 887 } 888 } 889 890 memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln); 891 memcpy(ar_spa(ah), &itaddr, ah->ar_pln); 892 ah->ar_op = htons(ARPOP_REPLY); 893 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 894 switch (ifp->if_type) { 895 case IFT_ARCNET: 896 arh = (struct arc_header *)sa.sa_data; 897 arh->arc_dhost = *ar_tha(ah); 898 arh->arc_type = ARCTYPE_ARP; 899 break; 900 case IFT_ISO88025: 901 /* Re-arrange the source/dest address */ 902 memcpy(th->iso88025_dhost, th->iso88025_shost, 903 sizeof th->iso88025_dhost); 904 memcpy(th->iso88025_shost, IF_LLADDR(ifp), 905 sizeof th->iso88025_shost); 906 /* Set the source routing bit if neccesary */ 907 if (th->iso88025_dhost[0] & TR_RII) { 908 th->iso88025_dhost[0] &= ~TR_RII; 909 if (TR_RCF_RIFLEN(th->rcf) > 2) 910 th->iso88025_shost[0] |= TR_RII; 911 } 912 /* Copy the addresses, ac and fc into sa_data */ 913 memcpy(sa.sa_data, th->iso88025_dhost, 914 (sizeof th->iso88025_dhost) * 2); 915 sa.sa_data[(sizeof th->iso88025_dhost) * 2] = TR_AC; 916 sa.sa_data[(sizeof th->iso88025_dhost) * 2 + 1] = TR_LLC_FRAME; 917 break; 918 case IFT_ETHER: 919 case IFT_FDDI: 920 /* 921 * May not be correct for types not explictly 922 * listed, but it is our best guess. 923 */ 924 default: 925 eh = (struct ether_header *)sa.sa_data; 926 memcpy(eh->ether_dhost, ar_tha(ah), sizeof eh->ether_dhost); 927 eh->ether_type = htons(ETHERTYPE_ARP); 928 break; 929 } 930 sa.sa_family = AF_UNSPEC; 931 sa.sa_len = sizeof sa; 932 lwkt_serialize_enter(ifp->if_serializer); 933 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 934 lwkt_serialize_exit(ifp->if_serializer); 935 return; 936 } 937 938 #ifdef SMP 939 940 static 941 int 942 arp_update_msghandler(struct lwkt_msg *lmsg) 943 { 944 struct netmsg_arp_update *msg = (struct netmsg_arp_update *)lmsg; 945 int nextcpu; 946 947 arp_update_oncpu(msg->m, msg->saddr, msg->create, FALSE); 948 949 nextcpu = mycpuid + 1; 950 if (nextcpu < ncpus) { 951 lwkt_forwardmsg(rtable_portfn(nextcpu), &msg->lmsg); 952 } else { 953 lwkt_replymsg(&msg->lmsg, 0); 954 } 955 return (0); 956 } 957 958 #endif 959 960 #endif 961 962 /* 963 * Free an arp entry. If the arp entry is actively referenced or represents 964 * a static entry we only clear it back to an unresolved state, otherwise 965 * we destroy the entry entirely. 966 * 967 * Note that static entries are created when route add ... -interface is used 968 * to create an interface route to a (direct) destination. 969 */ 970 static void 971 arptfree(struct llinfo_arp *la) 972 { 973 struct rtentry *rt = la->la_rt; 974 struct sockaddr_dl *sdl; 975 976 if (rt == NULL) 977 panic("arptfree"); 978 sdl = SDL(rt->rt_gateway); 979 if (sdl != NULL && 980 ((rt->rt_refcnt > 0 && sdl->sdl_family == AF_LINK) || 981 (rt->rt_flags & RTF_STATIC))) { 982 sdl->sdl_alen = 0; 983 la->la_preempt = la->la_asked = 0; 984 rt->rt_flags &= ~RTF_REJECT; 985 return; 986 } 987 rtrequest(RTM_DELETE, rt_key(rt), NULL, rt_mask(rt), 0, NULL); 988 } 989 990 /* 991 * Lookup or enter a new address in arptab. 992 */ 993 static struct llinfo_arp * 994 arplookup(in_addr_t addr, boolean_t create, boolean_t proxy) 995 { 996 struct rtentry *rt; 997 struct sockaddr_inarp sin = { sizeof sin, AF_INET }; 998 const char *why = NULL; 999 1000 sin.sin_addr.s_addr = addr; 1001 sin.sin_other = proxy ? SIN_PROXY : 0; 1002 if (create) 1003 rt = rtlookup((struct sockaddr *)&sin); 1004 else 1005 rt = rtpurelookup((struct sockaddr *)&sin); 1006 if (rt == NULL) 1007 return (NULL); 1008 rt->rt_refcnt--; 1009 1010 if (rt->rt_flags & RTF_GATEWAY) 1011 why = "host is not on local network"; 1012 else if (!(rt->rt_flags & RTF_LLINFO)) 1013 why = "could not allocate llinfo"; 1014 else if (rt->rt_gateway->sa_family != AF_LINK) 1015 why = "gateway route is not ours"; 1016 1017 if (why) { 1018 if (create) { 1019 log(LOG_DEBUG, "arplookup %s failed: %s\n", 1020 inet_ntoa(sin.sin_addr), why); 1021 } 1022 if (rt->rt_refcnt <= 0 && (rt->rt_flags & RTF_WASCLONED)) { 1023 /* No references to this route. Purge it. */ 1024 rtrequest(RTM_DELETE, rt_key(rt), rt->rt_gateway, 1025 rt_mask(rt), rt->rt_flags, NULL); 1026 } 1027 return (NULL); 1028 } 1029 return (rt->rt_llinfo); 1030 } 1031 1032 void 1033 arp_ifinit(struct ifnet *ifp, struct ifaddr *ifa) 1034 { 1035 if (IA_SIN(ifa)->sin_addr.s_addr != INADDR_ANY) 1036 arprequest(ifp, &IA_SIN(ifa)->sin_addr, &IA_SIN(ifa)->sin_addr, 1037 IF_LLADDR(ifp)); 1038 ifa->ifa_rtrequest = arp_rtrequest; 1039 ifa->ifa_flags |= RTF_CLONING; 1040 } 1041 1042 static void 1043 arp_init(void) 1044 { 1045 int cpu; 1046 1047 for (cpu = 0; cpu < ncpus2; cpu++) 1048 LIST_INIT(&llinfo_arp_list[cpu]); 1049 netisr_register(NETISR_ARP, cpu0_portfn, arpintr); 1050 } 1051 1052 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0); 1053