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 #include <sys/mplock2.h> 105 106 #ifdef CARP 107 #include <netinet/ip_carp.h> 108 #endif 109 110 #define SIN(s) ((struct sockaddr_in *)s) 111 #define SDL(s) ((struct sockaddr_dl *)s) 112 113 SYSCTL_DECL(_net_link_ether); 114 SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, ""); 115 116 /* timer values */ 117 static int arpt_prune = (5*60*1); /* walk list every 5 minutes */ 118 static int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */ 119 static int arpt_down = 20; /* once declared down, don't send for 20 sec */ 120 121 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, prune_intvl, CTLFLAG_RW, 122 &arpt_prune, 0, ""); 123 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW, 124 &arpt_keep, 0, ""); 125 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, host_down_time, CTLFLAG_RW, 126 &arpt_down, 0, ""); 127 128 #define rt_expire rt_rmx.rmx_expire 129 130 struct llinfo_arp { 131 LIST_ENTRY(llinfo_arp) la_le; 132 struct rtentry *la_rt; 133 struct mbuf *la_hold; /* last packet until resolved/timeout */ 134 struct lwkt_port *la_msgport; /* last packet's msgport */ 135 u_short la_preempt; /* countdown for pre-expiry arps */ 136 u_short la_asked; /* #times we QUERIED following expiration */ 137 }; 138 139 static LIST_HEAD(, llinfo_arp) llinfo_arp_list[MAXCPU]; 140 141 static int arp_maxtries = 5; 142 static int useloopback = 1; /* use loopback interface for local traffic */ 143 static int arp_proxyall = 0; 144 145 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW, 146 &arp_maxtries, 0, "ARP resolution attempts before returning error"); 147 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW, 148 &useloopback, 0, "Use the loopback interface for local traffic"); 149 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW, 150 &arp_proxyall, 0, "Enable proxy ARP for all suitable requests"); 151 152 static int arp_mpsafe = 1; 153 TUNABLE_INT("net.link.ether.inet.arp_mpsafe", &arp_mpsafe); 154 155 static void arp_rtrequest(int, struct rtentry *, struct rt_addrinfo *); 156 static void arprequest(struct ifnet *, const struct in_addr *, 157 const struct in_addr *, const u_char *); 158 static void arprequest_async(struct ifnet *, const struct in_addr *, 159 const struct in_addr *, const u_char *); 160 static void arpintr(struct netmsg *); 161 static void arptfree(struct llinfo_arp *); 162 static void arptimer(void *); 163 static struct llinfo_arp * 164 arplookup(in_addr_t, boolean_t, boolean_t, boolean_t); 165 #ifdef INET 166 static void in_arpinput(struct mbuf *); 167 #endif 168 169 static struct callout arptimer_ch[MAXCPU]; 170 171 /* 172 * Timeout routine. Age arp_tab entries periodically. 173 */ 174 /* ARGSUSED */ 175 static void 176 arptimer(void *ignored_arg) 177 { 178 struct llinfo_arp *la, *nla; 179 180 crit_enter(); 181 LIST_FOREACH_MUTABLE(la, &llinfo_arp_list[mycpuid], la_le, nla) { 182 if (la->la_rt->rt_expire && la->la_rt->rt_expire <= time_second) 183 arptfree(la); 184 } 185 callout_reset(&arptimer_ch[mycpuid], arpt_prune * hz, arptimer, NULL); 186 crit_exit(); 187 } 188 189 /* 190 * Parallel to llc_rtrequest. 191 */ 192 static void 193 arp_rtrequest(int req, struct rtentry *rt, struct rt_addrinfo *info) 194 { 195 struct sockaddr *gate = rt->rt_gateway; 196 struct llinfo_arp *la = rt->rt_llinfo; 197 198 struct sockaddr_dl null_sdl = { sizeof null_sdl, AF_LINK }; 199 static boolean_t arpinit_done[MAXCPU]; 200 201 if (!arpinit_done[mycpuid]) { 202 arpinit_done[mycpuid] = TRUE; 203 callout_init(&arptimer_ch[mycpuid]); 204 callout_reset(&arptimer_ch[mycpuid], hz, arptimer, NULL); 205 } 206 if (rt->rt_flags & RTF_GATEWAY) 207 return; 208 209 switch (req) { 210 case RTM_ADD: 211 /* 212 * XXX: If this is a manually added route to interface 213 * such as older version of routed or gated might provide, 214 * restore cloning bit. 215 */ 216 if (!(rt->rt_flags & RTF_HOST) && 217 SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff) 218 rt->rt_flags |= RTF_CLONING; 219 if (rt->rt_flags & RTF_CLONING) { 220 /* 221 * Case 1: This route should come from a route to iface. 222 */ 223 rt_setgate(rt, rt_key(rt), 224 (struct sockaddr *)&null_sdl, 225 RTL_DONTREPORT); 226 gate = rt->rt_gateway; 227 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 228 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 229 rt->rt_expire = time_second; 230 break; 231 } 232 /* Announce a new entry if requested. */ 233 if (rt->rt_flags & RTF_ANNOUNCE) { 234 arprequest_async(rt->rt_ifp, 235 &SIN(rt_key(rt))->sin_addr, 236 &SIN(rt_key(rt))->sin_addr, 237 LLADDR(SDL(gate))); 238 } 239 /*FALLTHROUGH*/ 240 case RTM_RESOLVE: 241 if (gate->sa_family != AF_LINK || 242 gate->sa_len < sizeof(struct sockaddr_dl)) { 243 log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n"); 244 break; 245 } 246 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 247 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 248 if (la != NULL) 249 break; /* This happens on a route change */ 250 /* 251 * Case 2: This route may come from cloning, or a manual route 252 * add with a LL address. 253 */ 254 R_Malloc(la, struct llinfo_arp *, sizeof *la); 255 rt->rt_llinfo = la; 256 if (la == NULL) { 257 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); 258 break; 259 } 260 bzero(la, sizeof *la); 261 la->la_rt = rt; 262 rt->rt_flags |= RTF_LLINFO; 263 LIST_INSERT_HEAD(&llinfo_arp_list[mycpuid], la, la_le); 264 265 #ifdef INET 266 /* 267 * This keeps the multicast addresses from showing up 268 * in `arp -a' listings as unresolved. It's not actually 269 * functional. Then the same for broadcast. 270 */ 271 if (IN_MULTICAST(ntohl(SIN(rt_key(rt))->sin_addr.s_addr))) { 272 ETHER_MAP_IP_MULTICAST(&SIN(rt_key(rt))->sin_addr, 273 LLADDR(SDL(gate))); 274 SDL(gate)->sdl_alen = 6; 275 rt->rt_expire = 0; 276 } 277 if (in_broadcast(SIN(rt_key(rt))->sin_addr, rt->rt_ifp)) { 278 memcpy(LLADDR(SDL(gate)), rt->rt_ifp->if_broadcastaddr, 279 rt->rt_ifp->if_addrlen); 280 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen; 281 rt->rt_expire = 0; 282 } 283 #endif 284 285 if (SIN(rt_key(rt))->sin_addr.s_addr == 286 (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) { 287 /* 288 * This test used to be 289 * if (loif.if_flags & IFF_UP) 290 * It allowed local traffic to be forced 291 * through the hardware by configuring the 292 * loopback down. However, it causes problems 293 * during network configuration for boards 294 * that can't receive packets they send. It 295 * is now necessary to clear "useloopback" and 296 * remove the route to force traffic out to 297 * the hardware. 298 */ 299 rt->rt_expire = 0; 300 bcopy(IF_LLADDR(rt->rt_ifp), LLADDR(SDL(gate)), 301 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen); 302 if (useloopback) 303 rt->rt_ifp = loif; 304 } 305 break; 306 307 case RTM_DELETE: 308 if (la == NULL) 309 break; 310 LIST_REMOVE(la, la_le); 311 rt->rt_llinfo = NULL; 312 rt->rt_flags &= ~RTF_LLINFO; 313 if (la->la_hold != NULL) 314 m_freem(la->la_hold); 315 Free(la); 316 break; 317 } 318 } 319 320 static struct mbuf * 321 arpreq_alloc(struct ifnet *ifp, const struct in_addr *sip, 322 const struct in_addr *tip, const u_char *enaddr) 323 { 324 struct mbuf *m; 325 struct arphdr *ah; 326 u_short ar_hrd; 327 328 if ((m = m_gethdr(MB_DONTWAIT, MT_DATA)) == NULL) 329 return NULL; 330 m->m_pkthdr.rcvif = NULL; 331 332 switch (ifp->if_type) { 333 case IFT_ETHER: 334 /* 335 * This may not be correct for types not explicitly 336 * listed, but this is our best guess 337 */ 338 default: 339 ar_hrd = htons(ARPHRD_ETHER); 340 341 m->m_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 342 m->m_pkthdr.len = m->m_len; 343 MH_ALIGN(m, m->m_len); 344 345 ah = mtod(m, struct arphdr *); 346 break; 347 } 348 349 ah->ar_hrd = ar_hrd; 350 ah->ar_pro = htons(ETHERTYPE_IP); 351 ah->ar_hln = ifp->if_addrlen; /* hardware address length */ 352 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 353 ah->ar_op = htons(ARPOP_REQUEST); 354 memcpy(ar_sha(ah), enaddr, ah->ar_hln); 355 memset(ar_tha(ah), 0, ah->ar_hln); 356 memcpy(ar_spa(ah), sip, ah->ar_pln); 357 memcpy(ar_tpa(ah), tip, ah->ar_pln); 358 359 return m; 360 } 361 362 static void 363 arpreq_send(struct ifnet *ifp, struct mbuf *m) 364 { 365 struct sockaddr sa; 366 struct ether_header *eh; 367 368 switch (ifp->if_type) { 369 case IFT_ETHER: 370 /* 371 * This may not be correct for types not explicitly 372 * listed, but this is our best guess 373 */ 374 default: 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 break; 380 } 381 382 sa.sa_family = AF_UNSPEC; 383 sa.sa_len = sizeof(sa); 384 ifp->if_output(ifp, m, &sa, NULL); 385 } 386 387 static void 388 arpreq_send_handler(struct netmsg *nmsg) 389 { 390 struct mbuf *m = ((struct netmsg_packet *)nmsg)->nm_packet; 391 struct ifnet *ifp = nmsg->nm_lmsg.u.ms_resultp; 392 393 arpreq_send(ifp, m); 394 /* nmsg was embedded in the mbuf, do not reply! */ 395 } 396 397 /* 398 * Broadcast an ARP request. Caller specifies: 399 * - arp header source ip address 400 * - arp header target ip address 401 * - arp header source ethernet address 402 * 403 * NOTE: Caller MUST NOT hold ifp's serializer 404 */ 405 static void 406 arprequest(struct ifnet *ifp, const struct in_addr *sip, 407 const struct in_addr *tip, const u_char *enaddr) 408 { 409 struct mbuf *m; 410 411 m = arpreq_alloc(ifp, sip, tip, enaddr); 412 if (m == NULL) 413 return; 414 arpreq_send(ifp, m); 415 } 416 417 /* 418 * Same as arprequest(), except: 419 * - Caller is allowed to hold ifp's serializer 420 * - Network output is done in TDF_NETWORK kernel thread 421 */ 422 static void 423 arprequest_async(struct ifnet *ifp, const struct in_addr *sip, 424 const struct in_addr *tip, const u_char *enaddr) 425 { 426 struct mbuf *m; 427 struct netmsg_packet *pmsg; 428 429 m = arpreq_alloc(ifp, sip, tip, enaddr); 430 if (m == NULL) 431 return; 432 433 pmsg = &m->m_hdr.mh_netmsg; 434 netmsg_init(&pmsg->nm_netmsg, NULL, &netisr_apanic_rport, 435 0, arpreq_send_handler); 436 pmsg->nm_packet = m; 437 pmsg->nm_netmsg.nm_lmsg.u.ms_resultp = ifp; 438 439 lwkt_sendmsg(cpu_portfn(mycpuid), &pmsg->nm_netmsg.nm_lmsg); 440 } 441 442 /* 443 * Resolve an IP address into an ethernet address. If success, 444 * desten is filled in. If there is no entry in arptab, 445 * set one up and broadcast a request for the IP address. 446 * Hold onto this mbuf and resend it once the address 447 * is finally resolved. A return value of 1 indicates 448 * that desten has been filled in and the packet should be sent 449 * normally; a 0 return indicates that the packet has been 450 * taken over here, either now or for later transmission. 451 */ 452 int 453 arpresolve(struct ifnet *ifp, struct rtentry *rt0, struct mbuf *m, 454 struct sockaddr *dst, u_char *desten) 455 { 456 struct rtentry *rt; 457 struct llinfo_arp *la = NULL; 458 struct sockaddr_dl *sdl; 459 460 if (m->m_flags & M_BCAST) { /* broadcast */ 461 memcpy(desten, ifp->if_broadcastaddr, ifp->if_addrlen); 462 return (1); 463 } 464 if (m->m_flags & M_MCAST) {/* multicast */ 465 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); 466 return (1); 467 } 468 if (rt0 != NULL) { 469 if (rt_llroute(dst, rt0, &rt) != 0) { 470 m_freem(m); 471 return 0; 472 } 473 la = rt->rt_llinfo; 474 } 475 if (la == NULL) { 476 la = arplookup(SIN(dst)->sin_addr.s_addr, 477 TRUE, RTL_REPORTMSG, FALSE); 478 if (la != NULL) 479 rt = la->la_rt; 480 } 481 if (la == NULL || rt == NULL) { 482 log(LOG_DEBUG, "arpresolve: can't allocate llinfo for %s%s%s\n", 483 inet_ntoa(SIN(dst)->sin_addr), la ? "la" : " ", 484 rt ? "rt" : ""); 485 m_freem(m); 486 return (0); 487 } 488 sdl = SDL(rt->rt_gateway); 489 /* 490 * Check the address family and length is valid, the address 491 * is resolved; otherwise, try to resolve. 492 */ 493 if ((rt->rt_expire == 0 || rt->rt_expire > time_second) && 494 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 495 /* 496 * If entry has an expiry time and it is approaching, 497 * see if we need to send an ARP request within this 498 * arpt_down interval. 499 */ 500 if ((rt->rt_expire != 0) && 501 (time_second + la->la_preempt > rt->rt_expire)) { 502 arprequest(ifp, 503 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 504 &SIN(dst)->sin_addr, 505 IF_LLADDR(ifp)); 506 la->la_preempt--; 507 } 508 509 bcopy(LLADDR(sdl), desten, sdl->sdl_alen); 510 return 1; 511 } 512 /* 513 * If ARP is disabled or static on this interface, stop. 514 * XXX 515 * Probably should not allocate empty llinfo struct if we are 516 * not going to be sending out an arp request. 517 */ 518 if (ifp->if_flags & (IFF_NOARP | IFF_STATICARP)) { 519 m_freem(m); 520 return (0); 521 } 522 /* 523 * There is an arptab entry, but no ethernet address 524 * response yet. Replace the held mbuf with this 525 * latest one. 526 */ 527 if (la->la_hold != NULL) 528 m_freem(la->la_hold); 529 la->la_hold = m; 530 la->la_msgport = curnetport; 531 if (rt->rt_expire || ((rt->rt_flags & RTF_STATIC) && !sdl->sdl_alen)) { 532 rt->rt_flags &= ~RTF_REJECT; 533 if (la->la_asked == 0 || rt->rt_expire != time_second) { 534 rt->rt_expire = time_second; 535 if (la->la_asked++ < arp_maxtries) { 536 arprequest(ifp, 537 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 538 &SIN(dst)->sin_addr, 539 IF_LLADDR(ifp)); 540 } else { 541 rt->rt_flags |= RTF_REJECT; 542 rt->rt_expire += arpt_down; 543 la->la_asked = 0; 544 la->la_preempt = arp_maxtries; 545 } 546 } 547 } 548 return (0); 549 } 550 551 /* 552 * Common length and type checks are done here, 553 * then the protocol-specific routine is called. 554 */ 555 static void 556 arpintr(struct netmsg *msg) 557 { 558 struct mbuf *m = ((struct netmsg_packet *)msg)->nm_packet; 559 struct arphdr *ar; 560 u_short ar_hrd; 561 562 if (m->m_len < sizeof(struct arphdr) && 563 (m = m_pullup(m, sizeof(struct arphdr))) == NULL) { 564 log(LOG_ERR, "arp: runt packet -- m_pullup failed\n"); 565 return; 566 } 567 ar = mtod(m, struct arphdr *); 568 569 ar_hrd = ntohs(ar->ar_hrd); 570 if (ar_hrd != ARPHRD_ETHER && ar_hrd != ARPHRD_IEEE802) { 571 log(LOG_ERR, "arp: unknown hardware address format (0x%2D)\n", 572 (unsigned char *)&ar->ar_hrd, ""); 573 m_freem(m); 574 return; 575 } 576 577 if (m->m_pkthdr.len < arphdr_len(ar)) { 578 if ((m = m_pullup(m, arphdr_len(ar))) == NULL) { 579 log(LOG_ERR, "arp: runt packet\n"); 580 return; 581 } 582 ar = mtod(m, struct arphdr *); 583 } 584 585 switch (ntohs(ar->ar_pro)) { 586 #ifdef INET 587 case ETHERTYPE_IP: 588 in_arpinput(m); 589 return; 590 #endif 591 } 592 m_freem(m); 593 /* msg was embedded in the mbuf, do not reply! */ 594 } 595 596 #ifdef INET 597 /* 598 * ARP for Internet protocols on 10 Mb/s Ethernet. 599 * Algorithm is that given in RFC 826. 600 * In addition, a sanity check is performed on the sender 601 * protocol address, to catch impersonators. 602 * We no longer handle negotiations for use of trailer protocol: 603 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 604 * along with IP replies if we wanted trailers sent to us, 605 * and also sent them in response to IP replies. 606 * This allowed either end to announce the desire to receive 607 * trailer packets. 608 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 609 * but formerly didn't normally send requests. 610 */ 611 612 static int log_arp_wrong_iface = 1; 613 static int log_arp_movements = 1; 614 static int log_arp_permanent_modify = 1; 615 616 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW, 617 &log_arp_wrong_iface, 0, 618 "Log arp packets arriving on the wrong interface"); 619 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_movements, CTLFLAG_RW, 620 &log_arp_movements, 0, 621 "Log arp replies from MACs different than the one in the cache"); 622 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_permanent_modify, CTLFLAG_RW, 623 &log_arp_permanent_modify, 0, 624 "Log arp replies from MACs different than the one " 625 "in the permanent arp entry"); 626 627 628 static void 629 arp_hold_output(struct netmsg *nmsg) 630 { 631 struct mbuf *m = ((struct netmsg_packet *)nmsg)->nm_packet; 632 struct rtentry *rt; 633 struct ifnet *ifp; 634 635 rt = nmsg->nm_lmsg.u.ms_resultp; 636 ifp = m->m_pkthdr.rcvif; 637 m->m_pkthdr.rcvif = NULL; 638 639 ifp->if_output(ifp, m, rt_key(rt), rt); 640 641 /* Drop the reference count bumped by the sender */ 642 RTFREE(rt); 643 644 /* nmsg was embedded in the mbuf, do not reply! */ 645 } 646 647 static void 648 arp_update_oncpu(struct mbuf *m, in_addr_t saddr, boolean_t create, 649 boolean_t generate_report, boolean_t dologging) 650 { 651 struct arphdr *ah = mtod(m, struct arphdr *); 652 struct ifnet *ifp = m->m_pkthdr.rcvif; 653 struct llinfo_arp *la; 654 struct sockaddr_dl *sdl; 655 struct rtentry *rt; 656 657 la = arplookup(saddr, create, generate_report, FALSE); 658 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { 659 struct in_addr isaddr = { saddr }; 660 661 /* the following is not an error when doing bridging */ 662 if (rt->rt_ifp != ifp) { 663 if (dologging && log_arp_wrong_iface) { 664 log(LOG_ERR, 665 "arp: %s is on %s " 666 "but got reply from %*D on %s\n", 667 inet_ntoa(isaddr), 668 rt->rt_ifp->if_xname, 669 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 670 ifp->if_xname); 671 } 672 return; 673 } 674 if (sdl->sdl_alen && 675 bcmp(ar_sha(ah), LLADDR(sdl), sdl->sdl_alen)) { 676 if (rt->rt_expire != 0) { 677 if (dologging && log_arp_movements) { 678 log(LOG_INFO, 679 "arp: %s moved from %*D to %*D on %s\n", 680 inet_ntoa(isaddr), 681 ifp->if_addrlen, (u_char *)LLADDR(sdl), 682 ":", ifp->if_addrlen, 683 (u_char *)ar_sha(ah), ":", 684 ifp->if_xname); 685 } 686 } else { 687 if (dologging && log_arp_permanent_modify) { 688 log(LOG_ERR, 689 "arp: %*D attempts to modify " 690 "permanent entry for %s on %s\n", 691 ifp->if_addrlen, (u_char *)ar_sha(ah), 692 ":", inet_ntoa(isaddr), ifp->if_xname); 693 } 694 return; 695 } 696 } 697 /* 698 * sanity check for the address length. 699 * XXX this does not work for protocols with variable address 700 * length. -is 701 */ 702 if (dologging && sdl->sdl_alen && sdl->sdl_alen != ah->ar_hln) { 703 log(LOG_WARNING, 704 "arp from %*D: new addr len %d, was %d", 705 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 706 ah->ar_hln, sdl->sdl_alen); 707 } 708 if (ifp->if_addrlen != ah->ar_hln) { 709 if (dologging) { 710 log(LOG_WARNING, 711 "arp from %*D: addr len: new %d, i/f %d " 712 "(ignored)", 713 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 714 ah->ar_hln, ifp->if_addrlen); 715 } 716 return; 717 } 718 memcpy(LLADDR(sdl), ar_sha(ah), sdl->sdl_alen = ah->ar_hln); 719 if (rt->rt_expire != 0) 720 rt->rt_expire = time_second + arpt_keep; 721 rt->rt_flags &= ~RTF_REJECT; 722 la->la_asked = 0; 723 la->la_preempt = arp_maxtries; 724 725 /* 726 * This particular cpu might have been holding an mbuf 727 * pending ARP resolution. If so, transmit the mbuf now. 728 */ 729 if (la->la_hold != NULL) { 730 struct mbuf *m = la->la_hold; 731 struct lwkt_port *port = la->la_msgport; 732 struct netmsg_packet *pmsg; 733 734 la->la_hold = NULL; 735 la->la_msgport = NULL; 736 737 m_adj(m, sizeof(struct ether_header)); 738 739 /* 740 * Make sure that this rtentry will not be freed 741 * before the packet is processed on the target 742 * msgport. The reference count will be dropped 743 * in the handler associated with this packet. 744 */ 745 rt->rt_refcnt++; 746 747 pmsg = &m->m_hdr.mh_netmsg; 748 netmsg_init(&pmsg->nm_netmsg, NULL, 749 &netisr_apanic_rport, 750 MSGF_MPSAFE | MSGF_PRIORITY, 751 arp_hold_output); 752 pmsg->nm_packet = m; 753 754 /* Record necessary information */ 755 m->m_pkthdr.rcvif = ifp; 756 pmsg->nm_netmsg.nm_lmsg.u.ms_resultp = rt; 757 758 lwkt_sendmsg(port, &pmsg->nm_netmsg.nm_lmsg); 759 } 760 } 761 } 762 763 #ifdef SMP 764 765 struct netmsg_arp_update { 766 struct netmsg netmsg; 767 struct mbuf *m; 768 in_addr_t saddr; 769 boolean_t create; 770 }; 771 772 static void arp_update_msghandler(struct netmsg *); 773 774 #endif 775 776 /* 777 * Called from arpintr() - this routine is run from a single cpu. 778 */ 779 static void 780 in_arpinput(struct mbuf *m) 781 { 782 struct arphdr *ah; 783 struct ifnet *ifp = m->m_pkthdr.rcvif; 784 struct ether_header *eh; 785 struct rtentry *rt; 786 struct ifaddr_container *ifac; 787 struct in_ifaddr_container *iac; 788 struct in_ifaddr *ia = NULL; 789 struct sockaddr sa; 790 struct in_addr isaddr, itaddr, myaddr; 791 #ifdef SMP 792 struct netmsg_arp_update msg; 793 #endif 794 uint8_t *enaddr = NULL; 795 int op; 796 int req_len; 797 798 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 799 if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) { 800 log(LOG_ERR, "in_arp: runt packet -- m_pullup failed\n"); 801 return; 802 } 803 804 ah = mtod(m, struct arphdr *); 805 op = ntohs(ah->ar_op); 806 memcpy(&isaddr, ar_spa(ah), sizeof isaddr); 807 memcpy(&itaddr, ar_tpa(ah), sizeof itaddr); 808 809 myaddr.s_addr = INADDR_ANY; 810 #ifdef CARP 811 if (ifp->if_carp != NULL) { 812 get_mplock(); 813 if (ifp->if_carp != NULL && 814 carp_iamatch(ifp->if_carp, &itaddr, &isaddr, &enaddr)) { 815 rel_mplock(); 816 myaddr = itaddr; 817 goto match; 818 } 819 rel_mplock(); 820 } 821 #endif 822 823 /* 824 * Check both target and sender IP addresses: 825 * 826 * If we receive the packet on the interface owning the address, 827 * then accept the address. 828 * 829 * For a bridge, we accept the address if the receive interface and 830 * the interface owning the address are on the same bridge. 831 * (This will change slightly when we have clusters of interfaces). 832 */ 833 LIST_FOREACH(iac, INADDR_HASH(itaddr.s_addr), ia_hash) { 834 ia = iac->ia; 835 836 /* Skip all ia's which don't match */ 837 if (itaddr.s_addr != ia->ia_addr.sin_addr.s_addr) 838 continue; 839 #ifdef CARP 840 if (ia->ia_ifp->if_type == IFT_CARP) 841 continue; 842 #endif 843 if (ia->ia_ifp == ifp) 844 goto match; 845 846 if (ifp->if_bridge && ia->ia_ifp && 847 ifp->if_bridge == ia->ia_ifp->if_bridge) 848 goto match; 849 } 850 LIST_FOREACH(iac, INADDR_HASH(isaddr.s_addr), ia_hash) { 851 ia = iac->ia; 852 853 /* Skip all ia's which don't match */ 854 if (isaddr.s_addr != ia->ia_addr.sin_addr.s_addr) 855 continue; 856 #ifdef CARP 857 if (ia->ia_ifp->if_type == IFT_CARP) 858 continue; 859 #endif 860 if (ia->ia_ifp == ifp) 861 goto match; 862 863 if (ifp->if_bridge && ia->ia_ifp && 864 ifp->if_bridge == ia->ia_ifp->if_bridge) 865 goto match; 866 } 867 /* 868 * No match, use the first inet address on the receive interface 869 * as a dummy address for the rest of the function. 870 */ 871 TAILQ_FOREACH(ifac, &ifp->if_addrheads[mycpuid], ifa_link) { 872 struct ifaddr *ifa = ifac->ifa; 873 874 if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_INET) { 875 ia = ifatoia(ifa); 876 goto match; 877 } 878 } 879 /* 880 * If we got here, we didn't find any suitable interface, 881 * so drop the packet. 882 */ 883 m_freem(m); 884 return; 885 886 match: 887 if (!enaddr) 888 enaddr = (uint8_t *)IF_LLADDR(ifp); 889 if (myaddr.s_addr == INADDR_ANY) 890 myaddr = ia->ia_addr.sin_addr; 891 if (!bcmp(ar_sha(ah), enaddr, ifp->if_addrlen)) { 892 m_freem(m); /* it's from me, ignore it. */ 893 return; 894 } 895 if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) { 896 log(LOG_ERR, 897 "arp: link address is broadcast for IP address %s!\n", 898 inet_ntoa(isaddr)); 899 m_freem(m); 900 return; 901 } 902 if (isaddr.s_addr == myaddr.s_addr && myaddr.s_addr != 0) { 903 log(LOG_ERR, 904 "arp: %*D is using my IP address %s!\n", 905 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 906 inet_ntoa(isaddr)); 907 itaddr = myaddr; 908 goto reply; 909 } 910 if (ifp->if_flags & IFF_STATICARP) 911 goto reply; 912 #ifdef SMP 913 netmsg_init(&msg.netmsg, NULL, &curthread->td_msgport, 914 0, arp_update_msghandler); 915 msg.m = m; 916 msg.saddr = isaddr.s_addr; 917 msg.create = (itaddr.s_addr == myaddr.s_addr); 918 lwkt_domsg(rtable_portfn(0), &msg.netmsg.nm_lmsg, 0); 919 #else 920 arp_update_oncpu(m, isaddr.s_addr, (itaddr.s_addr == myaddr.s_addr), 921 RTL_REPORTMSG, TRUE); 922 #endif 923 reply: 924 if (op != ARPOP_REQUEST) { 925 m_freem(m); 926 return; 927 } 928 if (itaddr.s_addr == myaddr.s_addr) { 929 /* I am the target */ 930 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 931 memcpy(ar_sha(ah), enaddr, ah->ar_hln); 932 } else { 933 struct llinfo_arp *la; 934 935 la = arplookup(itaddr.s_addr, FALSE, RTL_DONTREPORT, SIN_PROXY); 936 if (la == NULL) { 937 struct sockaddr_in sin; 938 939 if (!arp_proxyall) { 940 m_freem(m); 941 return; 942 } 943 944 bzero(&sin, sizeof sin); 945 sin.sin_family = AF_INET; 946 sin.sin_len = sizeof sin; 947 sin.sin_addr = itaddr; 948 949 rt = rtpurelookup((struct sockaddr *)&sin); 950 if (rt == NULL) { 951 m_freem(m); 952 return; 953 } 954 --rt->rt_refcnt; 955 /* 956 * Don't send proxies for nodes on the same interface 957 * as this one came out of, or we'll get into a fight 958 * over who claims what Ether address. 959 */ 960 if (rt->rt_ifp == ifp) { 961 m_freem(m); 962 return; 963 } 964 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 965 memcpy(ar_sha(ah), enaddr, ah->ar_hln); 966 #ifdef DEBUG_PROXY 967 kprintf("arp: proxying for %s\n", inet_ntoa(itaddr)); 968 #endif 969 } else { 970 struct sockaddr_dl *sdl; 971 972 rt = la->la_rt; 973 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 974 sdl = SDL(rt->rt_gateway); 975 memcpy(ar_sha(ah), LLADDR(sdl), ah->ar_hln); 976 } 977 } 978 979 memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln); 980 memcpy(ar_spa(ah), &itaddr, ah->ar_pln); 981 ah->ar_op = htons(ARPOP_REPLY); 982 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 983 switch (ifp->if_type) { 984 case IFT_ETHER: 985 /* 986 * May not be correct for types not explictly 987 * listed, but it is our best guess. 988 */ 989 default: 990 eh = (struct ether_header *)sa.sa_data; 991 memcpy(eh->ether_dhost, ar_tha(ah), sizeof eh->ether_dhost); 992 eh->ether_type = htons(ETHERTYPE_ARP); 993 break; 994 } 995 sa.sa_family = AF_UNSPEC; 996 sa.sa_len = sizeof sa; 997 ifp->if_output(ifp, m, &sa, NULL); 998 } 999 1000 #ifdef SMP 1001 1002 static void 1003 arp_update_msghandler(struct netmsg *netmsg) 1004 { 1005 struct netmsg_arp_update *msg = (struct netmsg_arp_update *)netmsg; 1006 int nextcpu; 1007 1008 /* 1009 * This message handler will be called on all of the CPUs, 1010 * however, we only need to generate rtmsg on CPU0. 1011 */ 1012 arp_update_oncpu(msg->m, msg->saddr, msg->create, 1013 mycpuid == 0 ? RTL_REPORTMSG : RTL_DONTREPORT, 1014 mycpuid == 0); 1015 1016 nextcpu = mycpuid + 1; 1017 if (nextcpu < ncpus) 1018 lwkt_forwardmsg(rtable_portfn(nextcpu), &msg->netmsg.nm_lmsg); 1019 else 1020 lwkt_replymsg(&msg->netmsg.nm_lmsg, 0); 1021 } 1022 1023 #endif /* SMP */ 1024 1025 #endif /* INET */ 1026 1027 /* 1028 * Free an arp entry. If the arp entry is actively referenced or represents 1029 * a static entry we only clear it back to an unresolved state, otherwise 1030 * we destroy the entry entirely. 1031 * 1032 * Note that static entries are created when route add ... -interface is used 1033 * to create an interface route to a (direct) destination. 1034 */ 1035 static void 1036 arptfree(struct llinfo_arp *la) 1037 { 1038 struct rtentry *rt = la->la_rt; 1039 struct sockaddr_dl *sdl; 1040 1041 if (rt == NULL) 1042 panic("arptfree"); 1043 sdl = SDL(rt->rt_gateway); 1044 if (sdl != NULL && 1045 ((rt->rt_refcnt > 0 && sdl->sdl_family == AF_LINK) || 1046 (rt->rt_flags & RTF_STATIC))) { 1047 sdl->sdl_alen = 0; 1048 la->la_preempt = la->la_asked = 0; 1049 rt->rt_flags &= ~RTF_REJECT; 1050 return; 1051 } 1052 rtrequest(RTM_DELETE, rt_key(rt), NULL, rt_mask(rt), 0, NULL); 1053 } 1054 1055 /* 1056 * Lookup or enter a new address in arptab. 1057 */ 1058 static struct llinfo_arp * 1059 arplookup(in_addr_t addr, boolean_t create, boolean_t generate_report, 1060 boolean_t proxy) 1061 { 1062 struct rtentry *rt; 1063 struct sockaddr_inarp sin = { sizeof sin, AF_INET }; 1064 const char *why = NULL; 1065 1066 sin.sin_addr.s_addr = addr; 1067 sin.sin_other = proxy ? SIN_PROXY : 0; 1068 if (create) { 1069 rt = _rtlookup((struct sockaddr *)&sin, 1070 generate_report, RTL_DOCLONE); 1071 } else { 1072 rt = rtpurelookup((struct sockaddr *)&sin); 1073 } 1074 if (rt == NULL) 1075 return (NULL); 1076 rt->rt_refcnt--; 1077 1078 if (rt->rt_flags & RTF_GATEWAY) 1079 why = "host is not on local network"; 1080 else if (!(rt->rt_flags & RTF_LLINFO)) 1081 why = "could not allocate llinfo"; 1082 else if (rt->rt_gateway->sa_family != AF_LINK) 1083 why = "gateway route is not ours"; 1084 1085 if (why) { 1086 if (create) { 1087 log(LOG_DEBUG, "arplookup %s failed: %s\n", 1088 inet_ntoa(sin.sin_addr), why); 1089 } 1090 if (rt->rt_refcnt <= 0 && (rt->rt_flags & RTF_WASCLONED)) { 1091 /* No references to this route. Purge it. */ 1092 rtrequest(RTM_DELETE, rt_key(rt), rt->rt_gateway, 1093 rt_mask(rt), rt->rt_flags, NULL); 1094 } 1095 return (NULL); 1096 } 1097 return (rt->rt_llinfo); 1098 } 1099 1100 void 1101 arp_ifinit(struct ifnet *ifp, struct ifaddr *ifa) 1102 { 1103 if (IA_SIN(ifa)->sin_addr.s_addr != INADDR_ANY) { 1104 arprequest_async(ifp, &IA_SIN(ifa)->sin_addr, 1105 &IA_SIN(ifa)->sin_addr, IF_LLADDR(ifp)); 1106 } 1107 ifa->ifa_rtrequest = arp_rtrequest; 1108 ifa->ifa_flags |= RTF_CLONING; 1109 } 1110 1111 void 1112 arp_iainit(struct ifnet *ifp, const struct in_addr *addr, const u_char *enaddr) 1113 { 1114 if (addr->s_addr != INADDR_ANY) 1115 arprequest_async(ifp, addr, addr, enaddr); 1116 } 1117 1118 static void 1119 arp_init(void) 1120 { 1121 uint32_t flags; 1122 int cpu; 1123 1124 for (cpu = 0; cpu < ncpus2; cpu++) 1125 LIST_INIT(&llinfo_arp_list[cpu]); 1126 1127 if (arp_mpsafe) { 1128 flags = NETISR_FLAG_MPSAFE; 1129 kprintf("arp: MPSAFE\n"); 1130 } else { 1131 flags = NETISR_FLAG_NOTMPSAFE; 1132 } 1133 netisr_register(NETISR_ARP, cpu0_portfn, pktinfo_portfn_cpu0, 1134 arpintr, flags); 1135 } 1136 1137 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0); 1138