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, 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 RTL_DONTREPORT); 225 gate = rt->rt_gateway; 226 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 227 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 228 rt->rt_expire = time_second; 229 break; 230 } 231 /* Announce a new entry if requested. */ 232 if (rt->rt_flags & RTF_ANNOUNCE) { 233 arprequest_async(rt->rt_ifp, 234 &SIN(rt_key(rt))->sin_addr, 235 &SIN(rt_key(rt))->sin_addr, 236 LLADDR(SDL(gate))); 237 } 238 /*FALLTHROUGH*/ 239 case RTM_RESOLVE: 240 if (gate->sa_family != AF_LINK || 241 gate->sa_len < sizeof(struct sockaddr_dl)) { 242 log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n"); 243 break; 244 } 245 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 246 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 247 if (la != NULL) 248 break; /* This happens on a route change */ 249 /* 250 * Case 2: This route may come from cloning, or a manual route 251 * add with a LL address. 252 */ 253 R_Malloc(la, struct llinfo_arp *, sizeof *la); 254 rt->rt_llinfo = la; 255 if (la == NULL) { 256 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); 257 break; 258 } 259 bzero(la, sizeof *la); 260 la->la_rt = rt; 261 rt->rt_flags |= RTF_LLINFO; 262 LIST_INSERT_HEAD(&llinfo_arp_list[mycpuid], la, la_le); 263 264 #ifdef INET 265 /* 266 * This keeps the multicast addresses from showing up 267 * in `arp -a' listings as unresolved. It's not actually 268 * functional. Then the same for broadcast. 269 */ 270 if (IN_MULTICAST(ntohl(SIN(rt_key(rt))->sin_addr.s_addr))) { 271 ETHER_MAP_IP_MULTICAST(&SIN(rt_key(rt))->sin_addr, 272 LLADDR(SDL(gate))); 273 SDL(gate)->sdl_alen = 6; 274 rt->rt_expire = 0; 275 } 276 if (in_broadcast(SIN(rt_key(rt))->sin_addr, rt->rt_ifp)) { 277 memcpy(LLADDR(SDL(gate)), rt->rt_ifp->if_broadcastaddr, 278 rt->rt_ifp->if_addrlen); 279 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen; 280 rt->rt_expire = 0; 281 } 282 #endif 283 284 if (SIN(rt_key(rt))->sin_addr.s_addr == 285 (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) { 286 /* 287 * This test used to be 288 * if (loif.if_flags & IFF_UP) 289 * It allowed local traffic to be forced 290 * through the hardware by configuring the 291 * loopback down. However, it causes problems 292 * during network configuration for boards 293 * that can't receive packets they send. It 294 * is now necessary to clear "useloopback" and 295 * remove the route to force traffic out to 296 * the hardware. 297 */ 298 rt->rt_expire = 0; 299 bcopy(IF_LLADDR(rt->rt_ifp), LLADDR(SDL(gate)), 300 SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen); 301 if (useloopback) 302 rt->rt_ifp = loif; 303 } 304 break; 305 306 case RTM_DELETE: 307 if (la == NULL) 308 break; 309 LIST_REMOVE(la, la_le); 310 rt->rt_llinfo = NULL; 311 rt->rt_flags &= ~RTF_LLINFO; 312 if (la->la_hold != NULL) 313 m_freem(la->la_hold); 314 Free(la); 315 break; 316 } 317 } 318 319 static struct mbuf * 320 arpreq_alloc(struct ifnet *ifp, const struct in_addr *sip, 321 const struct in_addr *tip, const u_char *enaddr) 322 { 323 struct mbuf *m; 324 struct arphdr *ah; 325 u_short ar_hrd; 326 327 if ((m = m_gethdr(MB_DONTWAIT, MT_DATA)) == NULL) 328 return NULL; 329 m->m_pkthdr.rcvif = NULL; 330 331 switch (ifp->if_type) { 332 case IFT_ETHER: 333 /* 334 * This may not be correct for types not explicitly 335 * listed, but this is our best guess 336 */ 337 default: 338 ar_hrd = htons(ARPHRD_ETHER); 339 340 m->m_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 341 m->m_pkthdr.len = m->m_len; 342 MH_ALIGN(m, m->m_len); 343 344 ah = mtod(m, struct arphdr *); 345 break; 346 } 347 348 ah->ar_hrd = ar_hrd; 349 ah->ar_pro = htons(ETHERTYPE_IP); 350 ah->ar_hln = ifp->if_addrlen; /* hardware address length */ 351 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 352 ah->ar_op = htons(ARPOP_REQUEST); 353 memcpy(ar_sha(ah), enaddr, ah->ar_hln); 354 memset(ar_tha(ah), 0, ah->ar_hln); 355 memcpy(ar_spa(ah), sip, ah->ar_pln); 356 memcpy(ar_tpa(ah), tip, ah->ar_pln); 357 358 return m; 359 } 360 361 static void 362 arpreq_send(struct ifnet *ifp, struct mbuf *m) 363 { 364 struct sockaddr sa; 365 struct ether_header *eh; 366 367 switch (ifp->if_type) { 368 case IFT_ETHER: 369 /* 370 * This may not be correct for types not explicitly 371 * listed, but this is our best guess 372 */ 373 default: 374 eh = (struct ether_header *)sa.sa_data; 375 /* if_output() will not swap */ 376 eh->ether_type = htons(ETHERTYPE_ARP); 377 memcpy(eh->ether_dhost, ifp->if_broadcastaddr, ifp->if_addrlen); 378 break; 379 } 380 381 sa.sa_family = AF_UNSPEC; 382 sa.sa_len = sizeof(sa); 383 ifp->if_output(ifp, m, &sa, NULL); 384 } 385 386 static void 387 arpreq_send_handler(struct netmsg *nmsg) 388 { 389 struct mbuf *m = ((struct netmsg_packet *)nmsg)->nm_packet; 390 struct ifnet *ifp = nmsg->nm_lmsg.u.ms_resultp; 391 392 arpreq_send(ifp, m); 393 /* nmsg was embedded in the mbuf, do not reply! */ 394 } 395 396 /* 397 * Broadcast an ARP request. Caller specifies: 398 * - arp header source ip address 399 * - arp header target ip address 400 * - arp header source ethernet address 401 * 402 * NOTE: Caller MUST NOT hold ifp's serializer 403 */ 404 static void 405 arprequest(struct ifnet *ifp, const struct in_addr *sip, 406 const struct in_addr *tip, const u_char *enaddr) 407 { 408 struct mbuf *m; 409 410 m = arpreq_alloc(ifp, sip, tip, enaddr); 411 if (m == NULL) 412 return; 413 arpreq_send(ifp, m); 414 } 415 416 /* 417 * Same as arprequest(), except: 418 * - Caller is allowed to hold ifp's serializer 419 * - Network output is done in TDF_NETWORK kernel thread 420 */ 421 static void 422 arprequest_async(struct ifnet *ifp, const struct in_addr *sip, 423 const struct in_addr *tip, const u_char *enaddr) 424 { 425 struct mbuf *m; 426 struct netmsg_packet *pmsg; 427 428 m = arpreq_alloc(ifp, sip, tip, enaddr); 429 if (m == NULL) 430 return; 431 432 pmsg = &m->m_hdr.mh_netmsg; 433 netmsg_init(&pmsg->nm_netmsg, &netisr_apanic_rport, 0, 434 arpreq_send_handler); 435 pmsg->nm_packet = m; 436 pmsg->nm_netmsg.nm_lmsg.u.ms_resultp = ifp; 437 438 lwkt_sendmsg(cpu_portfn(mycpuid), &pmsg->nm_netmsg.nm_lmsg); 439 } 440 441 /* 442 * Resolve an IP address into an ethernet address. If success, 443 * desten is filled in. If there is no entry in arptab, 444 * set one up and broadcast a request for the IP address. 445 * Hold onto this mbuf and resend it once the address 446 * is finally resolved. A return value of 1 indicates 447 * that desten has been filled in and the packet should be sent 448 * normally; a 0 return indicates that the packet has been 449 * taken over here, either now or for later transmission. 450 */ 451 int 452 arpresolve(struct ifnet *ifp, struct rtentry *rt0, struct mbuf *m, 453 struct sockaddr *dst, u_char *desten) 454 { 455 struct rtentry *rt; 456 struct llinfo_arp *la = NULL; 457 struct sockaddr_dl *sdl; 458 459 if (m->m_flags & M_BCAST) { /* broadcast */ 460 memcpy(desten, ifp->if_broadcastaddr, ifp->if_addrlen); 461 return (1); 462 } 463 if (m->m_flags & M_MCAST) {/* multicast */ 464 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); 465 return (1); 466 } 467 if (rt0 != NULL) { 468 if (rt_llroute(dst, rt0, &rt) != 0) { 469 m_freem(m); 470 return 0; 471 } 472 la = rt->rt_llinfo; 473 } 474 if (la == NULL) { 475 la = arplookup(SIN(dst)->sin_addr.s_addr, 476 TRUE, RTL_REPORTMSG, FALSE); 477 if (la != NULL) 478 rt = la->la_rt; 479 } 480 if (la == NULL || rt == NULL) { 481 log(LOG_DEBUG, "arpresolve: can't allocate llinfo for %s%s%s\n", 482 inet_ntoa(SIN(dst)->sin_addr), la ? "la" : " ", 483 rt ? "rt" : ""); 484 m_freem(m); 485 return (0); 486 } 487 sdl = SDL(rt->rt_gateway); 488 /* 489 * Check the address family and length is valid, the address 490 * is resolved; otherwise, try to resolve. 491 */ 492 if ((rt->rt_expire == 0 || rt->rt_expire > time_second) && 493 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 494 /* 495 * If entry has an expiry time and it is approaching, 496 * see if we need to send an ARP request within this 497 * arpt_down interval. 498 */ 499 if ((rt->rt_expire != 0) && 500 (time_second + la->la_preempt > rt->rt_expire)) { 501 arprequest(ifp, 502 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 503 &SIN(dst)->sin_addr, 504 IF_LLADDR(ifp)); 505 la->la_preempt--; 506 } 507 508 bcopy(LLADDR(sdl), desten, sdl->sdl_alen); 509 return 1; 510 } 511 /* 512 * If ARP is disabled on this interface, stop. 513 * XXX 514 * Probably should not allocate empty llinfo struct if we are 515 * not going to be sending out an arp request. 516 */ 517 if (ifp->if_flags & IFF_NOARP) { 518 m_freem(m); 519 return (0); 520 } 521 /* 522 * There is an arptab entry, but no ethernet address 523 * response yet. Replace the held mbuf with this 524 * latest one. 525 */ 526 if (la->la_hold != NULL) 527 m_freem(la->la_hold); 528 la->la_hold = m; 529 la->la_msgport = curnetport; 530 if (rt->rt_expire || ((rt->rt_flags & RTF_STATIC) && !sdl->sdl_alen)) { 531 rt->rt_flags &= ~RTF_REJECT; 532 if (la->la_asked == 0 || rt->rt_expire != time_second) { 533 rt->rt_expire = time_second; 534 if (la->la_asked++ < arp_maxtries) { 535 arprequest(ifp, 536 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 537 &SIN(dst)->sin_addr, 538 IF_LLADDR(ifp)); 539 } else { 540 rt->rt_flags |= RTF_REJECT; 541 rt->rt_expire += arpt_down; 542 la->la_asked = 0; 543 la->la_preempt = arp_maxtries; 544 } 545 } 546 } 547 return (0); 548 } 549 550 /* 551 * Common length and type checks are done here, 552 * then the protocol-specific routine is called. 553 */ 554 static void 555 arpintr(struct netmsg *msg) 556 { 557 struct mbuf *m = ((struct netmsg_packet *)msg)->nm_packet; 558 struct arphdr *ar; 559 u_short ar_hrd; 560 561 if (m->m_len < sizeof(struct arphdr) && 562 (m = m_pullup(m, sizeof(struct arphdr))) == NULL) { 563 log(LOG_ERR, "arp: runt packet -- m_pullup failed\n"); 564 return; 565 } 566 ar = mtod(m, struct arphdr *); 567 568 ar_hrd = ntohs(ar->ar_hrd); 569 if (ar_hrd != ARPHRD_ETHER && ar_hrd != ARPHRD_IEEE802) { 570 log(LOG_ERR, "arp: unknown hardware address format (0x%2D)\n", 571 (unsigned char *)&ar->ar_hrd, ""); 572 m_freem(m); 573 return; 574 } 575 576 if (m->m_pkthdr.len < arphdr_len(ar)) { 577 if ((m = m_pullup(m, arphdr_len(ar))) == NULL) { 578 log(LOG_ERR, "arp: runt packet\n"); 579 return; 580 } 581 ar = mtod(m, struct arphdr *); 582 } 583 584 switch (ntohs(ar->ar_pro)) { 585 #ifdef INET 586 case ETHERTYPE_IP: 587 in_arpinput(m); 588 return; 589 #endif 590 } 591 m_freem(m); 592 /* msg was embedded in the mbuf, do not reply! */ 593 } 594 595 #ifdef INET 596 /* 597 * ARP for Internet protocols on 10 Mb/s Ethernet. 598 * Algorithm is that given in RFC 826. 599 * In addition, a sanity check is performed on the sender 600 * protocol address, to catch impersonators. 601 * We no longer handle negotiations for use of trailer protocol: 602 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 603 * along with IP replies if we wanted trailers sent to us, 604 * and also sent them in response to IP replies. 605 * This allowed either end to announce the desire to receive 606 * trailer packets. 607 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 608 * but formerly didn't normally send requests. 609 */ 610 static int log_arp_wrong_iface = 1; 611 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW, 612 &log_arp_wrong_iface, 0, 613 "log arp packets arriving on the wrong interface"); 614 615 static void 616 arp_hold_output(struct netmsg *nmsg) 617 { 618 struct mbuf *m = ((struct netmsg_packet *)nmsg)->nm_packet; 619 struct rtentry *rt; 620 struct ifnet *ifp; 621 622 rt = nmsg->nm_lmsg.u.ms_resultp; 623 ifp = m->m_pkthdr.rcvif; 624 m->m_pkthdr.rcvif = NULL; 625 626 ifp->if_output(ifp, m, rt_key(rt), rt); 627 628 /* Drop the reference count bumped by the sender */ 629 RTFREE(rt); 630 631 /* nmsg was embedded in the mbuf, do not reply! */ 632 } 633 634 static void 635 arp_update_oncpu(struct mbuf *m, in_addr_t saddr, boolean_t create, 636 boolean_t generate_report, boolean_t dologging) 637 { 638 struct arphdr *ah = mtod(m, struct arphdr *); 639 struct ifnet *ifp = m->m_pkthdr.rcvif; 640 struct llinfo_arp *la; 641 struct sockaddr_dl *sdl; 642 struct rtentry *rt; 643 644 la = arplookup(saddr, create, generate_report, FALSE); 645 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { 646 struct in_addr isaddr = { saddr }; 647 648 /* the following is not an error when doing bridging */ 649 if (rt->rt_ifp != ifp) { 650 if (dologging && log_arp_wrong_iface) { 651 log(LOG_ERR, 652 "arp: %s is on %s " 653 "but got reply from %*D on %s\n", 654 inet_ntoa(isaddr), 655 rt->rt_ifp->if_xname, 656 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 657 ifp->if_xname); 658 } 659 return; 660 } 661 if (sdl->sdl_alen && 662 bcmp(ar_sha(ah), LLADDR(sdl), sdl->sdl_alen)) { 663 if (rt->rt_expire != 0) { 664 if (dologging) { 665 log(LOG_INFO, 666 "arp: %s moved from %*D to %*D on %s\n", 667 inet_ntoa(isaddr), 668 ifp->if_addrlen, (u_char *)LLADDR(sdl), 669 ":", ifp->if_addrlen, 670 (u_char *)ar_sha(ah), ":", 671 ifp->if_xname); 672 } 673 } else { 674 if (dologging) { 675 log(LOG_ERR, 676 "arp: %*D attempts to modify " 677 "permanent entry for %s on %s\n", 678 ifp->if_addrlen, (u_char *)ar_sha(ah), 679 ":", inet_ntoa(isaddr), ifp->if_xname); 680 } 681 return; 682 } 683 } 684 /* 685 * sanity check for the address length. 686 * XXX this does not work for protocols with variable address 687 * length. -is 688 */ 689 if (dologging && sdl->sdl_alen && sdl->sdl_alen != ah->ar_hln) { 690 log(LOG_WARNING, 691 "arp from %*D: new addr len %d, was %d", 692 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 693 ah->ar_hln, sdl->sdl_alen); 694 } 695 if (ifp->if_addrlen != ah->ar_hln) { 696 if (dologging) { 697 log(LOG_WARNING, 698 "arp from %*D: addr len: new %d, i/f %d " 699 "(ignored)", 700 ifp->if_addrlen, (u_char *) ar_sha(ah), ":", 701 ah->ar_hln, ifp->if_addrlen); 702 } 703 return; 704 } 705 memcpy(LLADDR(sdl), ar_sha(ah), sdl->sdl_alen = ah->ar_hln); 706 if (rt->rt_expire != 0) 707 rt->rt_expire = time_second + arpt_keep; 708 rt->rt_flags &= ~RTF_REJECT; 709 la->la_asked = 0; 710 la->la_preempt = arp_maxtries; 711 712 /* 713 * This particular cpu might have been holding an mbuf 714 * pending ARP resolution. If so, transmit the mbuf now. 715 */ 716 if (la->la_hold != NULL) { 717 struct mbuf *m = la->la_hold; 718 struct lwkt_port *port = la->la_msgport; 719 struct netmsg_packet *pmsg; 720 721 la->la_hold = NULL; 722 la->la_msgport = NULL; 723 724 m_adj(m, sizeof(struct ether_header)); 725 726 /* 727 * Make sure that this rtentry will not be freed 728 * before the packet is processed on the target 729 * msgport. The reference count will be dropped 730 * in the handler associated with this packet. 731 */ 732 rt->rt_refcnt++; 733 734 pmsg = &m->m_hdr.mh_netmsg; 735 netmsg_init(&pmsg->nm_netmsg, &netisr_apanic_rport, 736 MSGF_MPSAFE | MSGF_PRIORITY, 737 arp_hold_output); 738 pmsg->nm_packet = m; 739 740 /* Record necessary information */ 741 m->m_pkthdr.rcvif = ifp; 742 pmsg->nm_netmsg.nm_lmsg.u.ms_resultp = rt; 743 744 lwkt_sendmsg(port, &pmsg->nm_netmsg.nm_lmsg); 745 } 746 } 747 } 748 749 #ifdef SMP 750 751 struct netmsg_arp_update { 752 struct netmsg netmsg; 753 struct mbuf *m; 754 in_addr_t saddr; 755 boolean_t create; 756 }; 757 758 static void arp_update_msghandler(struct netmsg *); 759 760 #endif 761 762 /* 763 * Called from arpintr() - this routine is run from a single cpu. 764 */ 765 static void 766 in_arpinput(struct mbuf *m) 767 { 768 struct arphdr *ah; 769 struct ifnet *ifp = m->m_pkthdr.rcvif; 770 struct ether_header *eh; 771 struct rtentry *rt; 772 struct ifaddr_container *ifac; 773 struct in_ifaddr_container *iac; 774 struct in_ifaddr *ia = NULL; 775 struct sockaddr sa; 776 struct in_addr isaddr, itaddr, myaddr; 777 #ifdef SMP 778 struct netmsg_arp_update msg; 779 #endif 780 uint8_t *enaddr = NULL; 781 int op; 782 int req_len; 783 784 req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); 785 if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) { 786 log(LOG_ERR, "in_arp: runt packet -- m_pullup failed\n"); 787 return; 788 } 789 790 ah = mtod(m, struct arphdr *); 791 op = ntohs(ah->ar_op); 792 memcpy(&isaddr, ar_spa(ah), sizeof isaddr); 793 memcpy(&itaddr, ar_tpa(ah), sizeof itaddr); 794 795 myaddr.s_addr = INADDR_ANY; 796 #ifdef CARP 797 if (ifp->if_carp != NULL) { 798 get_mplock(); 799 if (ifp->if_carp != NULL && 800 carp_iamatch(ifp->if_carp, &itaddr, &isaddr, &enaddr)) { 801 rel_mplock(); 802 myaddr = itaddr; 803 goto match; 804 } 805 rel_mplock(); 806 } 807 #endif 808 809 /* 810 * Check both target and sender IP addresses: 811 * 812 * If we receive the packet on the interface owning the address, 813 * then accept the address. 814 * 815 * For a bridge, we accept the address if the receive interface and 816 * the interface owning the address are on the same bridge. 817 * (This will change slightly when we have clusters of interfaces). 818 */ 819 LIST_FOREACH(iac, INADDR_HASH(itaddr.s_addr), ia_hash) { 820 ia = iac->ia; 821 822 /* Skip all ia's which don't match */ 823 if (itaddr.s_addr != ia->ia_addr.sin_addr.s_addr) 824 continue; 825 #ifdef CARP 826 if (ia->ia_ifp->if_type == IFT_CARP) 827 continue; 828 #endif 829 if (ia->ia_ifp == ifp) 830 goto match; 831 832 if (ifp->if_bridge && ia->ia_ifp && 833 ifp->if_bridge == ia->ia_ifp->if_bridge) 834 goto match; 835 } 836 LIST_FOREACH(iac, INADDR_HASH(isaddr.s_addr), ia_hash) { 837 ia = iac->ia; 838 839 /* Skip all ia's which don't match */ 840 if (isaddr.s_addr != ia->ia_addr.sin_addr.s_addr) 841 continue; 842 #ifdef CARP 843 if (ia->ia_ifp->if_type == IFT_CARP) 844 continue; 845 #endif 846 if (ia->ia_ifp == ifp) 847 goto match; 848 849 if (ifp->if_bridge && ia->ia_ifp && 850 ifp->if_bridge == ia->ia_ifp->if_bridge) 851 goto match; 852 } 853 /* 854 * No match, use the first inet address on the receive interface 855 * as a dummy address for the rest of the function. 856 */ 857 TAILQ_FOREACH(ifac, &ifp->if_addrheads[mycpuid], ifa_link) { 858 struct ifaddr *ifa = ifac->ifa; 859 860 if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_INET) { 861 ia = ifatoia(ifa); 862 goto match; 863 } 864 } 865 /* 866 * If we got here, we didn't find any suitable interface, 867 * so drop the packet. 868 */ 869 m_freem(m); 870 return; 871 872 match: 873 if (!enaddr) 874 enaddr = (uint8_t *)IF_LLADDR(ifp); 875 if (myaddr.s_addr == INADDR_ANY) 876 myaddr = ia->ia_addr.sin_addr; 877 if (!bcmp(ar_sha(ah), enaddr, ifp->if_addrlen)) { 878 m_freem(m); /* it's from me, ignore it. */ 879 return; 880 } 881 if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) { 882 log(LOG_ERR, 883 "arp: link address is broadcast for IP address %s!\n", 884 inet_ntoa(isaddr)); 885 m_freem(m); 886 return; 887 } 888 if (isaddr.s_addr == myaddr.s_addr && myaddr.s_addr != 0) { 889 log(LOG_ERR, 890 "arp: %*D is using my IP address %s!\n", 891 ifp->if_addrlen, (u_char *)ar_sha(ah), ":", 892 inet_ntoa(isaddr)); 893 itaddr = myaddr; 894 goto reply; 895 } 896 #ifdef SMP 897 netmsg_init(&msg.netmsg, &curthread->td_msgport, 0, 898 arp_update_msghandler); 899 msg.m = m; 900 msg.saddr = isaddr.s_addr; 901 msg.create = (itaddr.s_addr == myaddr.s_addr); 902 lwkt_domsg(rtable_portfn(0), &msg.netmsg.nm_lmsg, 0); 903 #else 904 arp_update_oncpu(m, isaddr.s_addr, (itaddr.s_addr == myaddr.s_addr), 905 RTL_REPORTMSG, TRUE); 906 #endif 907 reply: 908 if (op != ARPOP_REQUEST) { 909 m_freem(m); 910 return; 911 } 912 if (itaddr.s_addr == myaddr.s_addr) { 913 /* I am the target */ 914 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 915 memcpy(ar_sha(ah), enaddr, ah->ar_hln); 916 } else { 917 struct llinfo_arp *la; 918 919 la = arplookup(itaddr.s_addr, FALSE, RTL_DONTREPORT, SIN_PROXY); 920 if (la == NULL) { 921 struct sockaddr_in sin; 922 923 if (!arp_proxyall) { 924 m_freem(m); 925 return; 926 } 927 928 bzero(&sin, sizeof sin); 929 sin.sin_family = AF_INET; 930 sin.sin_len = sizeof sin; 931 sin.sin_addr = itaddr; 932 933 rt = rtpurelookup((struct sockaddr *)&sin); 934 if (rt == NULL) { 935 m_freem(m); 936 return; 937 } 938 --rt->rt_refcnt; 939 /* 940 * Don't send proxies for nodes on the same interface 941 * as this one came out of, or we'll get into a fight 942 * over who claims what Ether address. 943 */ 944 if (rt->rt_ifp == ifp) { 945 m_freem(m); 946 return; 947 } 948 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 949 memcpy(ar_sha(ah), enaddr, ah->ar_hln); 950 #ifdef DEBUG_PROXY 951 kprintf("arp: proxying for %s\n", inet_ntoa(itaddr)); 952 #endif 953 } else { 954 struct sockaddr_dl *sdl; 955 956 rt = la->la_rt; 957 memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); 958 sdl = SDL(rt->rt_gateway); 959 memcpy(ar_sha(ah), LLADDR(sdl), ah->ar_hln); 960 } 961 } 962 963 memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln); 964 memcpy(ar_spa(ah), &itaddr, ah->ar_pln); 965 ah->ar_op = htons(ARPOP_REPLY); 966 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 967 switch (ifp->if_type) { 968 case IFT_ETHER: 969 /* 970 * May not be correct for types not explictly 971 * listed, but it is our best guess. 972 */ 973 default: 974 eh = (struct ether_header *)sa.sa_data; 975 memcpy(eh->ether_dhost, ar_tha(ah), sizeof eh->ether_dhost); 976 eh->ether_type = htons(ETHERTYPE_ARP); 977 break; 978 } 979 sa.sa_family = AF_UNSPEC; 980 sa.sa_len = sizeof sa; 981 ifp->if_output(ifp, m, &sa, NULL); 982 } 983 984 #ifdef SMP 985 986 static void 987 arp_update_msghandler(struct netmsg *netmsg) 988 { 989 struct netmsg_arp_update *msg = (struct netmsg_arp_update *)netmsg; 990 int nextcpu; 991 992 /* 993 * This message handler will be called on all of the CPUs, 994 * however, we only need to generate rtmsg on CPU0. 995 */ 996 arp_update_oncpu(msg->m, msg->saddr, msg->create, 997 mycpuid == 0 ? RTL_REPORTMSG : RTL_DONTREPORT, 998 mycpuid == 0); 999 1000 nextcpu = mycpuid + 1; 1001 if (nextcpu < ncpus) 1002 lwkt_forwardmsg(rtable_portfn(nextcpu), &msg->netmsg.nm_lmsg); 1003 else 1004 lwkt_replymsg(&msg->netmsg.nm_lmsg, 0); 1005 } 1006 1007 #endif /* SMP */ 1008 1009 #endif /* INET */ 1010 1011 /* 1012 * Free an arp entry. If the arp entry is actively referenced or represents 1013 * a static entry we only clear it back to an unresolved state, otherwise 1014 * we destroy the entry entirely. 1015 * 1016 * Note that static entries are created when route add ... -interface is used 1017 * to create an interface route to a (direct) destination. 1018 */ 1019 static void 1020 arptfree(struct llinfo_arp *la) 1021 { 1022 struct rtentry *rt = la->la_rt; 1023 struct sockaddr_dl *sdl; 1024 1025 if (rt == NULL) 1026 panic("arptfree"); 1027 sdl = SDL(rt->rt_gateway); 1028 if (sdl != NULL && 1029 ((rt->rt_refcnt > 0 && sdl->sdl_family == AF_LINK) || 1030 (rt->rt_flags & RTF_STATIC))) { 1031 sdl->sdl_alen = 0; 1032 la->la_preempt = la->la_asked = 0; 1033 rt->rt_flags &= ~RTF_REJECT; 1034 return; 1035 } 1036 rtrequest(RTM_DELETE, rt_key(rt), NULL, rt_mask(rt), 0, NULL); 1037 } 1038 1039 /* 1040 * Lookup or enter a new address in arptab. 1041 */ 1042 static struct llinfo_arp * 1043 arplookup(in_addr_t addr, boolean_t create, boolean_t generate_report, 1044 boolean_t proxy) 1045 { 1046 struct rtentry *rt; 1047 struct sockaddr_inarp sin = { sizeof sin, AF_INET }; 1048 const char *why = NULL; 1049 1050 sin.sin_addr.s_addr = addr; 1051 sin.sin_other = proxy ? SIN_PROXY : 0; 1052 if (create) { 1053 rt = _rtlookup((struct sockaddr *)&sin, 1054 generate_report, RTL_DOCLONE); 1055 } else { 1056 rt = rtpurelookup((struct sockaddr *)&sin); 1057 } 1058 if (rt == NULL) 1059 return (NULL); 1060 rt->rt_refcnt--; 1061 1062 if (rt->rt_flags & RTF_GATEWAY) 1063 why = "host is not on local network"; 1064 else if (!(rt->rt_flags & RTF_LLINFO)) 1065 why = "could not allocate llinfo"; 1066 else if (rt->rt_gateway->sa_family != AF_LINK) 1067 why = "gateway route is not ours"; 1068 1069 if (why) { 1070 if (create) { 1071 log(LOG_DEBUG, "arplookup %s failed: %s\n", 1072 inet_ntoa(sin.sin_addr), why); 1073 } 1074 if (rt->rt_refcnt <= 0 && (rt->rt_flags & RTF_WASCLONED)) { 1075 /* No references to this route. Purge it. */ 1076 rtrequest(RTM_DELETE, rt_key(rt), rt->rt_gateway, 1077 rt_mask(rt), rt->rt_flags, NULL); 1078 } 1079 return (NULL); 1080 } 1081 return (rt->rt_llinfo); 1082 } 1083 1084 void 1085 arp_ifinit(struct ifnet *ifp, struct ifaddr *ifa) 1086 { 1087 if (IA_SIN(ifa)->sin_addr.s_addr != INADDR_ANY) { 1088 arprequest_async(ifp, &IA_SIN(ifa)->sin_addr, 1089 &IA_SIN(ifa)->sin_addr, IF_LLADDR(ifp)); 1090 } 1091 ifa->ifa_rtrequest = arp_rtrequest; 1092 ifa->ifa_flags |= RTF_CLONING; 1093 } 1094 1095 void 1096 arp_iainit(struct ifnet *ifp, const struct in_addr *addr, const u_char *enaddr) 1097 { 1098 if (addr->s_addr != INADDR_ANY) 1099 arprequest_async(ifp, addr, addr, enaddr); 1100 } 1101 1102 static void 1103 arp_init(void) 1104 { 1105 uint32_t flags; 1106 int cpu; 1107 1108 for (cpu = 0; cpu < ncpus2; cpu++) 1109 LIST_INIT(&llinfo_arp_list[cpu]); 1110 1111 if (arp_mpsafe) { 1112 flags = NETISR_FLAG_MPSAFE; 1113 kprintf("arp: MPSAFE\n"); 1114 } else { 1115 flags = NETISR_FLAG_NOTMPSAFE; 1116 } 1117 netisr_register(NETISR_ARP, cpu0_portfn, arpintr, flags); 1118 } 1119 1120 SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0); 1121