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 1.59 2008/11/22 11:03:35 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 #include <sys/lock.h> 89 90 #include <net/if.h> 91 #include <net/if_dl.h> 92 #include <net/if_types.h> 93 #include <net/route.h> 94 #include <net/netisr.h> 95 #include <net/if_llc.h> 96 97 #include <netinet/in.h> 98 #include <netinet/in_var.h> 99 #include <netinet/if_ether.h> 100 101 #include <sys/thread2.h> 102 #include <sys/msgport2.h> 103 #include <net/netmsg2.h> 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 struct lwkt_port *la_msgport; /* last packet's msgport */ 134 u_short la_preempt; /* countdown for pre-expiry arps */ 135 u_short la_asked; /* #times we QUERIED following expiration */ 136 }; 137 138 static LIST_HEAD(, llinfo_arp) llinfo_arp_list[MAXCPU]; 139 140 static int arp_maxtries = 5; 141 static int useloopback = 1; /* use loopback interface for local traffic */ 142 static int arp_proxyall = 0; 143 144 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW, 145 &arp_maxtries, 0, ""); 146 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW, 147 &useloopback, 0, ""); 148 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW, 149 &arp_proxyall, 0, ""); 150 151 static int arp_mpsafe = 0; 152 TUNABLE_INT("net.link.ether.inet.arp_mpsafe", &arp_mpsafe); 153 154 static void arp_rtrequest(int, struct rtentry *, struct rt_addrinfo *); 155 static void arprequest(struct ifnet *, const struct in_addr *, 156 const struct in_addr *, const u_char *); 157 static void arprequest_async(struct ifnet *, const struct in_addr *, 158 const struct in_addr *, const u_char *); 159 static void arpintr(struct netmsg *); 160 static void arptfree(struct llinfo_arp *); 161 static void arptimer(void *); 162 static struct llinfo_arp * 163 arplookup(in_addr_t, boolean_t, boolean_t); 164 #ifdef INET 165 static void in_arpinput(struct mbuf *); 166 #endif 167 168 static struct callout arptimer_ch[MAXCPU]; 169 170 /* 171 * Timeout routine. Age arp_tab entries periodically. 172 */ 173 /* ARGSUSED */ 174 static void 175 arptimer(void *ignored_arg) 176 { 177 struct llinfo_arp *la, *nla; 178 179 crit_enter(); 180 LIST_FOREACH_MUTABLE(la, &llinfo_arp_list[mycpuid], la_le, nla) { 181 if (la->la_rt->rt_expire && la->la_rt->rt_expire <= time_second) 182 arptfree(la); 183 } 184 callout_reset(&arptimer_ch[mycpuid], arpt_prune * hz, arptimer, NULL); 185 crit_exit(); 186 } 187 188 /* 189 * Parallel to llc_rtrequest. 190 */ 191 static void 192 arp_rtrequest(int req, struct rtentry *rt, struct rt_addrinfo *info) 193 { 194 struct sockaddr *gate = rt->rt_gateway; 195 struct llinfo_arp *la = rt->rt_llinfo; 196 197 struct sockaddr_dl null_sdl = { sizeof null_sdl, AF_LINK }; 198 static boolean_t arpinit_done[MAXCPU]; 199 200 if (!arpinit_done[mycpuid]) { 201 arpinit_done[mycpuid] = TRUE; 202 callout_init(&arptimer_ch[mycpuid]); 203 callout_reset(&arptimer_ch[mycpuid], hz, arptimer, NULL); 204 } 205 if (rt->rt_flags & RTF_GATEWAY) 206 return; 207 208 switch (req) { 209 case RTM_ADD: 210 /* 211 * XXX: If this is a manually added route to interface 212 * such as older version of routed or gated might provide, 213 * restore cloning bit. 214 */ 215 if (!(rt->rt_flags & RTF_HOST) && 216 SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff) 217 rt->rt_flags |= RTF_CLONING; 218 if (rt->rt_flags & RTF_CLONING) { 219 /* 220 * Case 1: This route should come from a route to iface. 221 */ 222 rt_setgate(rt, rt_key(rt), 223 (struct sockaddr *)&null_sdl); 224 gate = rt->rt_gateway; 225 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 226 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 227 rt->rt_expire = time_second; 228 break; 229 } 230 /* Announce a new entry if requested. */ 231 if (rt->rt_flags & RTF_ANNOUNCE) { 232 arprequest_async(rt->rt_ifp, 233 &SIN(rt_key(rt))->sin_addr, 234 &SIN(rt_key(rt))->sin_addr, 235 LLADDR(SDL(gate))); 236 } 237 /*FALLTHROUGH*/ 238 case RTM_RESOLVE: 239 if (gate->sa_family != AF_LINK || 240 gate->sa_len < sizeof(struct sockaddr_dl)) { 241 log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n"); 242 break; 243 } 244 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 245 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 246 if (la != NULL) 247 break; /* This happens on a route change */ 248 /* 249 * Case 2: This route may come from cloning, or a manual route 250 * add with a LL address. 251 */ 252 R_Malloc(la, struct llinfo_arp *, sizeof *la); 253 rt->rt_llinfo = la; 254 if (la == NULL) { 255 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); 256 break; 257 } 258 bzero(la, sizeof *la); 259 la->la_rt = rt; 260 rt->rt_flags |= RTF_LLINFO; 261 LIST_INSERT_HEAD(&llinfo_arp_list[mycpuid], la, la_le); 262 263 #ifdef INET 264 /* 265 * This keeps the multicast addresses from showing up 266 * in `arp -a' listings as unresolved. It's not actually 267 * functional. Then the same for broadcast. 268 */ 269 if (IN_MULTICAST(ntohl(SIN(rt_key(rt))->sin_addr.s_addr))) { 270 ETHER_MAP_IP_MULTICAST(&SIN(rt_key(rt))->sin_addr, 271 LLADDR(SDL(gate))); 272 SDL(gate)->sdl_alen = 6; 273 rt->rt_expire = 0; 274 } 275 if (in_broadcast(SIN(rt_key(rt))->sin_addr, rt->rt_ifp)) { 276 memcpy(LLADDR(SDL(gate)), rt->rt_ifp->if_broadcastaddr, 277 rt->rt_ifp->if_addrlen); 278 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen; 279 rt->rt_expire = 0; 280 } 281 #endif 282 283 if (SIN(rt_key(rt))->sin_addr.s_addr == 284 (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) { 285 /* 286 * This test used to be 287 * if (loif.if_flags & IFF_UP) 288 * It allowed local traffic to be forced 289 * through the hardware by configuring the 290 * loopback down. However, it causes problems 291 * during network configuration for boards 292 * that can't receive packets they send. It 293 * is now necessary to clear "useloopback" and 294 * remove the route to force traffic out to 295 * the hardware. 296 */ 297 rt->rt_expire = 0; 298 bcopy(IF_LLADDR(rt->rt_ifp), LLADDR(SDL(gate)), 299 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen); 300 if (useloopback) 301 rt->rt_ifp = loif; 302 } 303 break; 304 305 case RTM_DELETE: 306 if (la == NULL) 307 break; 308 LIST_REMOVE(la, la_le); 309 rt->rt_llinfo = NULL; 310 rt->rt_flags &= ~RTF_LLINFO; 311 if (la->la_hold != NULL) 312 m_freem(la->la_hold); 313 Free(la); 314 break; 315 } 316 } 317 318 static struct mbuf * 319 arpreq_alloc(struct ifnet *ifp, const struct in_addr *sip, 320 const struct in_addr *tip, const u_char *enaddr) 321 { 322 struct mbuf *m; 323 struct arphdr *ah; 324 u_short ar_hrd; 325 326 if ((m = m_gethdr(MB_DONTWAIT, MT_DATA)) == NULL) 327 return NULL; 328 m->m_pkthdr.rcvif = NULL; 329 330 switch (ifp->if_type) { 331 case IFT_ETHER: 332 /* 333 * This may not be correct for types not explicitly 334 * listed, but this is our best guess 335 */ 336 default: 337 ar_hrd = htons(ARPHRD_ETHER); 338 339 m->m_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 340 m->m_pkthdr.len = m->m_len; 341 MH_ALIGN(m, m->m_len); 342 343 ah = mtod(m, struct arphdr *); 344 break; 345 } 346 347 ah->ar_hrd = ar_hrd; 348 ah->ar_pro = htons(ETHERTYPE_IP); 349 ah->ar_hln = ifp->if_addrlen; /* hardware address length */ 350 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 351 ah->ar_op = htons(ARPOP_REQUEST); 352 memcpy(ar_sha(ah), enaddr, ah->ar_hln); 353 memset(ar_tha(ah), 0, ah->ar_hln); 354 memcpy(ar_spa(ah), sip, ah->ar_pln); 355 memcpy(ar_tpa(ah), tip, ah->ar_pln); 356 357 return m; 358 } 359 360 static void 361 arpreq_send(struct ifnet *ifp, struct mbuf *m) 362 { 363 struct sockaddr sa; 364 struct ether_header *eh; 365 366 switch (ifp->if_type) { 367 case IFT_ETHER: 368 /* 369 * This may not be correct for types not explicitly 370 * listed, but this is our best guess 371 */ 372 default: 373 eh = (struct ether_header *)sa.sa_data; 374 /* if_output() will not swap */ 375 eh->ether_type = htons(ETHERTYPE_ARP); 376 memcpy(eh->ether_dhost, ifp->if_broadcastaddr, ifp->if_addrlen); 377 break; 378 } 379 380 sa.sa_family = AF_UNSPEC; 381 sa.sa_len = sizeof(sa); 382 ifp->if_output(ifp, m, &sa, NULL); 383 } 384 385 static void 386 arpreq_send_handler(struct netmsg *nmsg) 387 { 388 struct mbuf *m = ((struct netmsg_packet *)nmsg)->nm_packet; 389 struct ifnet *ifp = nmsg->nm_lmsg.u.ms_resultp; 390 391 arpreq_send(ifp, m); 392 /* nmsg was embedded in the mbuf, do not reply! */ 393 } 394 395 /* 396 * Broadcast an ARP request. Caller specifies: 397 * - arp header source ip address 398 * - arp header target ip address 399 * - arp header source ethernet address 400 * 401 * NOTE: Caller MUST NOT hold ifp's serializer 402 */ 403 static void 404 arprequest(struct ifnet *ifp, const struct in_addr *sip, 405 const struct in_addr *tip, const u_char *enaddr) 406 { 407 struct mbuf *m; 408 409 m = arpreq_alloc(ifp, sip, tip, enaddr); 410 if (m == NULL) 411 return; 412 arpreq_send(ifp, m); 413 } 414 415 /* 416 * Same as arprequest(), except: 417 * - Caller is allowed to hold ifp's serializer 418 * - Network output is done in TDF_NETWORK kernel thread 419 */ 420 static void 421 arprequest_async(struct ifnet *ifp, const struct in_addr *sip, 422 const struct in_addr *tip, const u_char *enaddr) 423 { 424 struct mbuf *m; 425 struct netmsg_packet *pmsg; 426 427 m = arpreq_alloc(ifp, sip, tip, enaddr); 428 if (m == NULL) 429 return; 430 431 pmsg = &m->m_hdr.mh_netmsg; 432 netmsg_init(&pmsg->nm_netmsg, &netisr_apanic_rport, 0, 433 arpreq_send_handler); 434 pmsg->nm_packet = m; 435 pmsg->nm_netmsg.nm_lmsg.u.ms_resultp = ifp; 436 437 lwkt_sendmsg(cpu_portfn(mycpuid), &pmsg->nm_netmsg.nm_lmsg); 438 } 439 440 /* 441 * Resolve an IP address into an ethernet address. If success, 442 * desten is filled in. If there is no entry in arptab, 443 * set one up and broadcast a request for the IP address. 444 * Hold onto this mbuf and resend it once the address 445 * is finally resolved. A return value of 1 indicates 446 * that desten has been filled in and the packet should be sent 447 * normally; a 0 return indicates that the packet has been 448 * taken over here, either now or for later transmission. 449 */ 450 int 451 arpresolve(struct ifnet *ifp, struct rtentry *rt0, struct mbuf *m, 452 struct sockaddr *dst, u_char *desten) 453 { 454 struct rtentry *rt; 455 struct llinfo_arp *la = NULL; 456 struct sockaddr_dl *sdl; 457 458 if (m->m_flags & M_BCAST) { /* broadcast */ 459 memcpy(desten, ifp->if_broadcastaddr, ifp->if_addrlen); 460 return (1); 461 } 462 if (m->m_flags & M_MCAST) {/* multicast */ 463 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); 464 return (1); 465 } 466 if (rt0 != NULL) { 467 if (rt_llroute(dst, rt0, &rt) != 0) { 468 m_freem(m); 469 return 0; 470 } 471 la = rt->rt_llinfo; 472 } 473 if (la == NULL) { 474 la = arplookup(SIN(dst)->sin_addr.s_addr, TRUE, FALSE); 475 if (la != NULL) 476 rt = la->la_rt; 477 } 478 if (la == NULL || rt == NULL) { 479 log(LOG_DEBUG, "arpresolve: can't allocate llinfo for %s%s%s\n", 480 inet_ntoa(SIN(dst)->sin_addr), la ? "la" : " ", 481 rt ? "rt" : ""); 482 m_freem(m); 483 return (0); 484 } 485 sdl = SDL(rt->rt_gateway); 486 /* 487 * Check the address family and length is valid, the address 488 * is resolved; otherwise, try to resolve. 489 */ 490 if ((rt->rt_expire == 0 || rt->rt_expire > time_second) && 491 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 492 /* 493 * If entry has an expiry time and it is approaching, 494 * see if we need to send an ARP request within this 495 * arpt_down interval. 496 */ 497 if ((rt->rt_expire != 0) && 498 (time_second + la->la_preempt > rt->rt_expire)) { 499 arprequest(ifp, 500 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 501 &SIN(dst)->sin_addr, 502 IF_LLADDR(ifp)); 503 la->la_preempt--; 504 } 505 506 bcopy(LLADDR(sdl), desten, sdl->sdl_alen); 507 return 1; 508 } 509 /* 510 * If ARP is disabled on this interface, stop. 511 * XXX 512 * Probably should not allocate empty llinfo struct if we are 513 * not going to be sending out an arp request. 514 */ 515 if (ifp->if_flags & IFF_NOARP) { 516 m_freem(m); 517 return (0); 518 } 519 /* 520 * There is an arptab entry, but no ethernet address 521 * response yet. Replace the held mbuf with this 522 * latest one. 523 */ 524 if (la->la_hold != NULL) 525 m_freem(la->la_hold); 526 la->la_hold = m; 527 la->la_msgport = curnetport; 528 if (rt->rt_expire || ((rt->rt_flags & RTF_STATIC) && !sdl->sdl_alen)) { 529 rt->rt_flags &= ~RTF_REJECT; 530 if (la->la_asked == 0 || rt->rt_expire != time_second) { 531 rt->rt_expire = time_second; 532 if (la->la_asked++ < arp_maxtries) { 533 arprequest(ifp, 534 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 535 &SIN(dst)->sin_addr, 536 IF_LLADDR(ifp)); 537 } else { 538 rt->rt_flags |= RTF_REJECT; 539 rt->rt_expire += arpt_down; 540 la->la_asked = 0; 541 la->la_preempt = arp_maxtries; 542 } 543 } 544 } 545 return (0); 546 } 547 548 /* 549 * Common length and type checks are done here, 550 * then the protocol-specific routine is called. 551 */ 552 static void 553 arpintr(struct netmsg *msg) 554 { 555 struct mbuf *m = ((struct netmsg_packet *)msg)->nm_packet; 556 struct arphdr *ar; 557 u_short ar_hrd; 558 559 if (m->m_len < sizeof(struct arphdr) && 560 (m = m_pullup(m, sizeof(struct arphdr))) == NULL) { 561 log(LOG_ERR, "arp: runt packet -- m_pullup failed\n"); 562 return; 563 } 564 ar = mtod(m, struct arphdr *); 565 566 ar_hrd = ntohs(ar->ar_hrd); 567 if (ar_hrd != ARPHRD_ETHER && ar_hrd != ARPHRD_IEEE802) { 568 log(LOG_ERR, "arp: unknown hardware address format (0x%2D)\n", 569 (unsigned char *)&ar->ar_hrd, ""); 570 m_freem(m); 571 return; 572 } 573 574 if (m->m_pkthdr.len < arphdr_len(ar)) { 575 if ((m = m_pullup(m, arphdr_len(ar))) == NULL) { 576 log(LOG_ERR, "arp: runt packet\n"); 577 return; 578 } 579 ar = mtod(m, struct arphdr *); 580 } 581 582 switch (ntohs(ar->ar_pro)) { 583 #ifdef INET 584 case ETHERTYPE_IP: 585 in_arpinput(m); 586 return; 587 #endif 588 } 589 m_freem(m); 590 /* msg was embedded in the mbuf, do not reply! */ 591 } 592 593 #ifdef INET 594 /* 595 * ARP for Internet protocols on 10 Mb/s Ethernet. 596 * Algorithm is that given in RFC 826. 597 * In addition, a sanity check is performed on the sender 598 * protocol address, to catch impersonators. 599 * We no longer handle negotiations for use of trailer protocol: 600 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 601 * along with IP replies if we wanted trailers sent to us, 602 * and also sent them in response to IP replies. 603 * This allowed either end to announce the desire to receive 604 * trailer packets. 605 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 606 * but formerly didn't normally send requests. 607 */ 608 static int log_arp_wrong_iface = 1; 609 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW, 610 &log_arp_wrong_iface, 0, 611 "log arp packets arriving on the wrong interface"); 612 613 static void 614 arp_hold_output(struct netmsg *nmsg) 615 { 616 struct mbuf *m = ((struct netmsg_packet *)nmsg)->nm_packet; 617 struct rtentry *rt; 618 struct ifnet *ifp; 619 620 rt = nmsg->nm_lmsg.u.ms_resultp; 621 ifp = m->m_pkthdr.rcvif; 622 m->m_pkthdr.rcvif = NULL; 623 624 ifp->if_output(ifp, m, rt_key(rt), rt); 625 626 /* Drop the reference count bumped by the sender */ 627 RTFREE(rt); 628 629 /* nmsg was embedded in the mbuf, do not reply! */ 630 } 631 632 static void 633 arp_update_oncpu(struct mbuf *m, in_addr_t saddr, boolean_t create, 634 boolean_t dologging) 635 { 636 struct arphdr *ah = mtod(m, struct arphdr *); 637 struct ifnet *ifp = m->m_pkthdr.rcvif; 638 struct llinfo_arp *la; 639 struct sockaddr_dl *sdl; 640 struct rtentry *rt; 641 642 la = arplookup(saddr, create, FALSE); 643 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { 644 struct in_addr isaddr = { saddr }; 645 646 /* the following is not an error when doing bridging */ 647 if (rt->rt_ifp != ifp) { 648 if (dologging && log_arp_wrong_iface) { 649 log(LOG_ERR, 650 "arp: %s is on %s " 651 "but got reply from %*D on %s\n", 652 inet_ntoa(isaddr), 653 rt->rt_ifp->if_xname, 654 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 655 ifp->if_xname); 656 } 657 return; 658 } 659 if (sdl->sdl_alen && 660 bcmp(ar_sha(ah), LLADDR(sdl), sdl->sdl_alen)) { 661 if (rt->rt_expire != 0) { 662 if (dologging) { 663 log(LOG_INFO, 664 "arp: %s moved from %*D to %*D on %s\n", 665 inet_ntoa(isaddr), 666 ifp->if_addrlen, (u_char *)LLADDR(sdl), 667 ":", ifp->if_addrlen, 668 (u_char *)ar_sha(ah), ":", 669 ifp->if_xname); 670 } 671 } else { 672 if (dologging) { 673 log(LOG_ERR, 674 "arp: %*D attempts to modify " 675 "permanent entry for %s on %s\n", 676 ifp->if_addrlen, (u_char *)ar_sha(ah), 677 ":", inet_ntoa(isaddr), ifp->if_xname); 678 } 679 return; 680 } 681 } 682 /* 683 * sanity check for the address length. 684 * XXX this does not work for protocols with variable address 685 * length. -is 686 */ 687 if (dologging && sdl->sdl_alen && sdl->sdl_alen != ah->ar_hln) { 688 log(LOG_WARNING, 689 "arp from %*D: new addr len %d, was %d", 690 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 691 ah->ar_hln, sdl->sdl_alen); 692 } 693 if (ifp->if_addrlen != ah->ar_hln) { 694 if (dologging) { 695 log(LOG_WARNING, 696 "arp from %*D: addr len: new %d, i/f %d " 697 "(ignored)", 698 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 699 ah->ar_hln, ifp->if_addrlen); 700 } 701 return; 702 } 703 memcpy(LLADDR(sdl), ar_sha(ah), sdl->sdl_alen = ah->ar_hln); 704 if (rt->rt_expire != 0) 705 rt->rt_expire = time_second + arpt_keep; 706 rt->rt_flags &= ~RTF_REJECT; 707 la->la_asked = 0; 708 la->la_preempt = arp_maxtries; 709 710 /* 711 * This particular cpu might have been holding an mbuf 712 * pending ARP resolution. If so, transmit the mbuf now. 713 */ 714 if (la->la_hold != NULL) { 715 struct mbuf *m = la->la_hold; 716 struct lwkt_port *port = la->la_msgport; 717 struct netmsg_packet *pmsg; 718 719 la->la_hold = NULL; 720 la->la_msgport = NULL; 721 722 m_adj(m, sizeof(struct ether_header)); 723 724 /* 725 * Make sure that this rtentry will not be freed 726 * before the packet is processed on the target 727 * msgport. The reference count will be dropped 728 * in the handler associated with this packet. 729 */ 730 rt->rt_refcnt++; 731 732 pmsg = &m->m_hdr.mh_netmsg; 733 netmsg_init(&pmsg->nm_netmsg, &netisr_apanic_rport, 734 MSGF_MPSAFE | MSGF_PRIORITY, 735 arp_hold_output); 736 pmsg->nm_packet = m; 737 738 /* Record necessary information */ 739 m->m_pkthdr.rcvif = ifp; 740 pmsg->nm_netmsg.nm_lmsg.u.ms_resultp = rt; 741 742 lwkt_sendmsg(port, &pmsg->nm_netmsg.nm_lmsg); 743 } 744 } 745 } 746 747 #ifdef SMP 748 749 struct netmsg_arp_update { 750 struct netmsg netmsg; 751 struct mbuf *m; 752 in_addr_t saddr; 753 boolean_t create; 754 }; 755 756 static void arp_update_msghandler(struct netmsg *); 757 758 #endif 759 760 /* 761 * Called from arpintr() - this routine is run from a single cpu. 762 */ 763 static void 764 in_arpinput(struct mbuf *m) 765 { 766 struct arphdr *ah; 767 struct ifnet *ifp = m->m_pkthdr.rcvif; 768 struct ether_header *eh; 769 struct rtentry *rt; 770 struct ifaddr_container *ifac; 771 struct in_ifaddr_container *iac; 772 struct in_ifaddr *ia = NULL; 773 struct sockaddr sa; 774 struct in_addr isaddr, itaddr, myaddr; 775 #ifdef SMP 776 struct netmsg_arp_update msg; 777 #endif 778 uint8_t *enaddr = NULL; 779 int op; 780 int req_len; 781 782 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 783 if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) { 784 log(LOG_ERR, "in_arp: runt packet -- m_pullup failed\n"); 785 return; 786 } 787 788 ah = mtod(m, struct arphdr *); 789 op = ntohs(ah->ar_op); 790 memcpy(&isaddr, ar_spa(ah), sizeof isaddr); 791 memcpy(&itaddr, ar_tpa(ah), sizeof itaddr); 792 793 myaddr.s_addr = INADDR_ANY; 794 #ifdef CARP 795 if (ifp->if_carp != NULL) { 796 get_mplock(); 797 if (ifp->if_carp != NULL && 798 carp_iamatch(ifp->if_carp, &itaddr, &isaddr, &enaddr)) { 799 rel_mplock(); 800 myaddr = itaddr; 801 goto match; 802 } 803 rel_mplock(); 804 } 805 #endif 806 807 /* 808 * Check both target and sender IP addresses: 809 * 810 * If we receive the packet on the interface owning the address, 811 * then accept the address. 812 * 813 * For a bridge, we accept the address if the receive interface and 814 * the interface owning the address are on the same bridge. 815 * (This will change slightly when we have clusters of interfaces). 816 */ 817 LIST_FOREACH(iac, INADDR_HASH(itaddr.s_addr), ia_hash) { 818 ia = iac->ia; 819 820 /* Skip all ia's which don't match */ 821 if (itaddr.s_addr != ia->ia_addr.sin_addr.s_addr) 822 continue; 823 #ifdef CARP 824 if (ia->ia_ifp->if_type == IFT_CARP) 825 continue; 826 #endif 827 if (ia->ia_ifp == ifp) 828 goto match; 829 830 if (ifp->if_bridge && ia->ia_ifp && 831 ifp->if_bridge == ia->ia_ifp->if_bridge) 832 goto match; 833 } 834 LIST_FOREACH(iac, INADDR_HASH(isaddr.s_addr), ia_hash) { 835 ia = iac->ia; 836 837 /* Skip all ia's which don't match */ 838 if (isaddr.s_addr != ia->ia_addr.sin_addr.s_addr) 839 continue; 840 #ifdef CARP 841 if (ia->ia_ifp->if_type == IFT_CARP) 842 continue; 843 #endif 844 if (ia->ia_ifp == ifp) 845 goto match; 846 847 if (ifp->if_bridge && ia->ia_ifp && 848 ifp->if_bridge == ia->ia_ifp->if_bridge) 849 goto match; 850 } 851 /* 852 * No match, use the first inet address on the receive interface 853 * as a dummy address for the rest of the function. 854 */ 855 TAILQ_FOREACH(ifac, &ifp->if_addrheads[mycpuid], ifa_link) { 856 struct ifaddr *ifa = ifac->ifa; 857 858 if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_INET) { 859 ia = ifatoia(ifa); 860 goto match; 861 } 862 } 863 /* 864 * If we got here, we didn't find any suitable interface, 865 * so drop the packet. 866 */ 867 m_freem(m); 868 return; 869 870 match: 871 if (!enaddr) 872 enaddr = (uint8_t *)IF_LLADDR(ifp); 873 if (myaddr.s_addr == INADDR_ANY) 874 myaddr = ia->ia_addr.sin_addr; 875 if (!bcmp(ar_sha(ah), enaddr, ifp->if_addrlen)) { 876 m_freem(m); /* it's from me, ignore it. */ 877 return; 878 } 879 if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) { 880 log(LOG_ERR, 881 "arp: link address is broadcast for IP address %s!\n", 882 inet_ntoa(isaddr)); 883 m_freem(m); 884 return; 885 } 886 if (isaddr.s_addr == myaddr.s_addr && myaddr.s_addr != 0) { 887 log(LOG_ERR, 888 "arp: %*D is using my IP address %s!\n", 889 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 890 inet_ntoa(isaddr)); 891 itaddr = myaddr; 892 goto reply; 893 } 894 #ifdef SMP 895 netmsg_init(&msg.netmsg, &curthread->td_msgport, 0, 896 arp_update_msghandler); 897 msg.m = m; 898 msg.saddr = isaddr.s_addr; 899 msg.create = (itaddr.s_addr == myaddr.s_addr); 900 lwkt_domsg(rtable_portfn(0), &msg.netmsg.nm_lmsg, 0); 901 #else 902 arp_update_oncpu(m, isaddr.s_addr, (itaddr.s_addr == myaddr.s_addr), 903 TRUE); 904 #endif 905 reply: 906 if (op != ARPOP_REQUEST) { 907 m_freem(m); 908 return; 909 } 910 if (itaddr.s_addr == myaddr.s_addr) { 911 /* I am the target */ 912 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 913 memcpy(ar_sha(ah), enaddr, ah->ar_hln); 914 } else { 915 struct llinfo_arp *la; 916 917 la = arplookup(itaddr.s_addr, FALSE, SIN_PROXY); 918 if (la == NULL) { 919 struct sockaddr_in sin; 920 921 if (!arp_proxyall) { 922 m_freem(m); 923 return; 924 } 925 926 bzero(&sin, sizeof sin); 927 sin.sin_family = AF_INET; 928 sin.sin_len = sizeof sin; 929 sin.sin_addr = itaddr; 930 931 rt = rtpurelookup((struct sockaddr *)&sin); 932 if (rt == NULL) { 933 m_freem(m); 934 return; 935 } 936 --rt->rt_refcnt; 937 /* 938 * Don't send proxies for nodes on the same interface 939 * as this one came out of, or we'll get into a fight 940 * over who claims what Ether address. 941 */ 942 if (rt->rt_ifp == ifp) { 943 m_freem(m); 944 return; 945 } 946 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 947 memcpy(ar_sha(ah), enaddr, ah->ar_hln); 948 #ifdef DEBUG_PROXY 949 kprintf("arp: proxying for %s\n", inet_ntoa(itaddr)); 950 #endif 951 } else { 952 struct sockaddr_dl *sdl; 953 954 rt = la->la_rt; 955 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 956 sdl = SDL(rt->rt_gateway); 957 memcpy(ar_sha(ah), LLADDR(sdl), ah->ar_hln); 958 } 959 } 960 961 memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln); 962 memcpy(ar_spa(ah), &itaddr, ah->ar_pln); 963 ah->ar_op = htons(ARPOP_REPLY); 964 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 965 switch (ifp->if_type) { 966 case IFT_ETHER: 967 /* 968 * May not be correct for types not explictly 969 * listed, but it is our best guess. 970 */ 971 default: 972 eh = (struct ether_header *)sa.sa_data; 973 memcpy(eh->ether_dhost, ar_tha(ah), sizeof eh->ether_dhost); 974 eh->ether_type = htons(ETHERTYPE_ARP); 975 break; 976 } 977 sa.sa_family = AF_UNSPEC; 978 sa.sa_len = sizeof sa; 979 ifp->if_output(ifp, m, &sa, NULL); 980 } 981 982 #ifdef SMP 983 984 static void 985 arp_update_msghandler(struct netmsg *netmsg) 986 { 987 struct netmsg_arp_update *msg = (struct netmsg_arp_update *)netmsg; 988 int nextcpu; 989 990 arp_update_oncpu(msg->m, msg->saddr, msg->create, mycpuid == 0); 991 992 nextcpu = mycpuid + 1; 993 if (nextcpu < ncpus) 994 lwkt_forwardmsg(rtable_portfn(nextcpu), &msg->netmsg.nm_lmsg); 995 else 996 lwkt_replymsg(&msg->netmsg.nm_lmsg, 0); 997 } 998 999 #endif /* SMP */ 1000 1001 #endif /* INET */ 1002 1003 /* 1004 * Free an arp entry. If the arp entry is actively referenced or represents 1005 * a static entry we only clear it back to an unresolved state, otherwise 1006 * we destroy the entry entirely. 1007 * 1008 * Note that static entries are created when route add ... -interface is used 1009 * to create an interface route to a (direct) destination. 1010 */ 1011 static void 1012 arptfree(struct llinfo_arp *la) 1013 { 1014 struct rtentry *rt = la->la_rt; 1015 struct sockaddr_dl *sdl; 1016 1017 if (rt == NULL) 1018 panic("arptfree"); 1019 sdl = SDL(rt->rt_gateway); 1020 if (sdl != NULL && 1021 ((rt->rt_refcnt > 0 && sdl->sdl_family == AF_LINK) || 1022 (rt->rt_flags & RTF_STATIC))) { 1023 sdl->sdl_alen = 0; 1024 la->la_preempt = la->la_asked = 0; 1025 rt->rt_flags &= ~RTF_REJECT; 1026 return; 1027 } 1028 rtrequest(RTM_DELETE, rt_key(rt), NULL, rt_mask(rt), 0, NULL); 1029 } 1030 1031 /* 1032 * Lookup or enter a new address in arptab. 1033 */ 1034 static struct llinfo_arp * 1035 arplookup(in_addr_t addr, boolean_t create, boolean_t proxy) 1036 { 1037 struct rtentry *rt; 1038 struct sockaddr_inarp sin = { sizeof sin, AF_INET }; 1039 const char *why = NULL; 1040 1041 sin.sin_addr.s_addr = addr; 1042 sin.sin_other = proxy ? SIN_PROXY : 0; 1043 if (create) 1044 rt = rtlookup((struct sockaddr *)&sin); 1045 else 1046 rt = rtpurelookup((struct sockaddr *)&sin); 1047 if (rt == NULL) 1048 return (NULL); 1049 rt->rt_refcnt--; 1050 1051 if (rt->rt_flags & RTF_GATEWAY) 1052 why = "host is not on local network"; 1053 else if (!(rt->rt_flags & RTF_LLINFO)) 1054 why = "could not allocate llinfo"; 1055 else if (rt->rt_gateway->sa_family != AF_LINK) 1056 why = "gateway route is not ours"; 1057 1058 if (why) { 1059 if (create) { 1060 log(LOG_DEBUG, "arplookup %s failed: %s\n", 1061 inet_ntoa(sin.sin_addr), why); 1062 } 1063 if (rt->rt_refcnt <= 0 && (rt->rt_flags & RTF_WASCLONED)) { 1064 /* No references to this route. Purge it. */ 1065 rtrequest(RTM_DELETE, rt_key(rt), rt->rt_gateway, 1066 rt_mask(rt), rt->rt_flags, NULL); 1067 } 1068 return (NULL); 1069 } 1070 return (rt->rt_llinfo); 1071 } 1072 1073 void 1074 arp_ifinit(struct ifnet *ifp, struct ifaddr *ifa) 1075 { 1076 if (IA_SIN(ifa)->sin_addr.s_addr != INADDR_ANY) { 1077 arprequest_async(ifp, &IA_SIN(ifa)->sin_addr, 1078 &IA_SIN(ifa)->sin_addr, IF_LLADDR(ifp)); 1079 } 1080 ifa->ifa_rtrequest = arp_rtrequest; 1081 ifa->ifa_flags |= RTF_CLONING; 1082 } 1083 1084 void 1085 arp_iainit(struct ifnet *ifp, const struct in_addr *addr, const u_char *enaddr) 1086 { 1087 if (addr->s_addr != INADDR_ANY) 1088 arprequest_async(ifp, addr, addr, enaddr); 1089 } 1090 1091 static void 1092 arp_init(void) 1093 { 1094 uint32_t flags; 1095 int cpu; 1096 1097 for (cpu = 0; cpu < ncpus2; cpu++) 1098 LIST_INIT(&llinfo_arp_list[cpu]); 1099 1100 if (arp_mpsafe) { 1101 flags = NETISR_FLAG_MPSAFE; 1102 kprintf("arp: MPSAFE\n"); 1103 } else { 1104 flags = NETISR_FLAG_NOTMPSAFE; 1105 } 1106 netisr_register(NETISR_ARP, cpu0_portfn, arpintr, flags); 1107 } 1108 1109 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0); 1110