1 /* $NetBSD: if_arp.c,v 1.147 2009/09/16 15:23:04 pooka Exp $ */ 2 3 /*- 4 * Copyright (c) 1998, 2000, 2008 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Public Access Networks Corporation ("Panix"). It was developed under 9 * contract to Panix by Eric Haszlakiewicz and Thor Lancelot Simon. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 22 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 23 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 24 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 26 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 30 * POSSIBILITY OF 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. Neither the name of the University nor the names of its contributors 46 * may be used to endorse or promote products derived from this software 47 * without specific prior written permission. 48 * 49 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 50 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 51 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 52 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 53 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 54 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 55 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 56 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 57 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 58 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 59 * SUCH DAMAGE. 60 * 61 * @(#)if_ether.c 8.2 (Berkeley) 9/26/94 62 */ 63 64 /* 65 * Ethernet address resolution protocol. 66 * TODO: 67 * add "inuse/lock" bit (or ref. count) along with valid bit 68 */ 69 70 #include <sys/cdefs.h> 71 __KERNEL_RCSID(0, "$NetBSD: if_arp.c,v 1.147 2009/09/16 15:23:04 pooka Exp $"); 72 73 #include "opt_ddb.h" 74 #include "opt_inet.h" 75 76 #ifdef INET 77 78 #include "bridge.h" 79 80 #include <sys/param.h> 81 #include <sys/systm.h> 82 #include <sys/callout.h> 83 #include <sys/malloc.h> 84 #include <sys/mbuf.h> 85 #include <sys/socket.h> 86 #include <sys/time.h> 87 #include <sys/timetc.h> 88 #include <sys/kernel.h> 89 #include <sys/errno.h> 90 #include <sys/ioctl.h> 91 #include <sys/syslog.h> 92 #include <sys/proc.h> 93 #include <sys/protosw.h> 94 #include <sys/domain.h> 95 #include <sys/sysctl.h> 96 #include <sys/socketvar.h> 97 #include <sys/percpu.h> 98 99 #include <net/ethertypes.h> 100 #include <net/if.h> 101 #include <net/if_dl.h> 102 #include <net/if_token.h> 103 #include <net/if_types.h> 104 #include <net/if_ether.h> 105 #include <net/route.h> 106 #include <net/net_stats.h> 107 108 #include <netinet/in.h> 109 #include <netinet/in_systm.h> 110 #include <netinet/in_var.h> 111 #include <netinet/ip.h> 112 #include <netinet/if_inarp.h> 113 114 #include "arcnet.h" 115 #if NARCNET > 0 116 #include <net/if_arc.h> 117 #endif 118 #include "fddi.h" 119 #if NFDDI > 0 120 #include <net/if_fddi.h> 121 #endif 122 #include "token.h" 123 #include "carp.h" 124 #if NCARP > 0 125 #include <netinet/ip_carp.h> 126 #endif 127 128 #define SIN(s) ((struct sockaddr_in *)s) 129 #define SRP(s) ((struct sockaddr_inarp *)s) 130 131 /* 132 * ARP trailer negotiation. Trailer protocol is not IP specific, 133 * but ARP request/response use IP addresses. 134 */ 135 #define ETHERTYPE_IPTRAILERS ETHERTYPE_TRAIL 136 137 /* timer values */ 138 int arpt_prune = (5*60*1); /* walk list every 5 minutes */ 139 int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */ 140 int arpt_down = 20; /* once declared down, don't send for 20 secs */ 141 int arpt_refresh = (5*60); /* time left before refreshing */ 142 #define rt_expire rt_rmx.rmx_expire 143 #define rt_pksent rt_rmx.rmx_pksent 144 145 static struct sockaddr *arp_setgate(struct rtentry *, struct sockaddr *, 146 const struct sockaddr *); 147 static void arptfree(struct llinfo_arp *); 148 static void arptimer(void *); 149 static struct llinfo_arp *arplookup1(struct mbuf *, const struct in_addr *, 150 int, int, struct rtentry *); 151 static struct llinfo_arp *arplookup(struct mbuf *, const struct in_addr *, 152 int, int); 153 static void in_arpinput(struct mbuf *); 154 155 LIST_HEAD(, llinfo_arp) llinfo_arp; 156 struct ifqueue arpintrq = { 157 .ifq_head = NULL, 158 .ifq_tail = NULL, 159 .ifq_len = 0, 160 .ifq_maxlen = 50, 161 .ifq_drops = 0, 162 }; 163 int arp_inuse, arp_allocated, arp_intimer; 164 int arp_maxtries = 5; 165 int useloopback = 1; /* use loopback interface for local traffic */ 166 int arpinit_done = 0; 167 168 static percpu_t *arpstat_percpu; 169 170 #define ARP_STAT_GETREF() _NET_STAT_GETREF(arpstat_percpu) 171 #define ARP_STAT_PUTREF() _NET_STAT_PUTREF(arpstat_percpu) 172 173 #define ARP_STATINC(x) _NET_STATINC(arpstat_percpu, x) 174 #define ARP_STATADD(x, v) _NET_STATADD(arpstat_percpu, x, v) 175 176 struct callout arptimer_ch; 177 178 /* revarp state */ 179 struct in_addr myip, srv_ip; 180 int myip_initialized = 0; 181 int revarp_in_progress = 0; 182 struct ifnet *myip_ifp = NULL; 183 184 #ifdef DDB 185 static void db_print_sa(const struct sockaddr *); 186 static void db_print_ifa(struct ifaddr *); 187 static void db_print_llinfo(void *); 188 static int db_show_rtentry(struct rtentry *, void *); 189 #endif 190 191 /* 192 * this should be elsewhere. 193 */ 194 195 static char * 196 lla_snprintf(u_int8_t *, int); 197 198 static char * 199 lla_snprintf(u_int8_t *adrp, int len) 200 { 201 #define NUMBUFS 3 202 static char buf[NUMBUFS][16*3]; 203 static int bnum = 0; 204 205 int i; 206 char *p; 207 208 p = buf[bnum]; 209 210 *p++ = hexdigits[(*adrp)>>4]; 211 *p++ = hexdigits[(*adrp++)&0xf]; 212 213 for (i=1; i<len && i<16; i++) { 214 *p++ = ':'; 215 *p++ = hexdigits[(*adrp)>>4]; 216 *p++ = hexdigits[(*adrp++)&0xf]; 217 } 218 219 *p = 0; 220 p = buf[bnum]; 221 bnum = (bnum + 1) % NUMBUFS; 222 return p; 223 } 224 225 DOMAIN_DEFINE(arpdomain); /* forward declare and add to link set */ 226 227 const struct protosw arpsw[] = { 228 { .pr_type = 0, 229 .pr_domain = &arpdomain, 230 .pr_protocol = 0, 231 .pr_flags = 0, 232 .pr_input = 0, 233 .pr_output = 0, 234 .pr_ctlinput = 0, 235 .pr_ctloutput = 0, 236 .pr_usrreq = 0, 237 .pr_init = arp_init, 238 .pr_fasttimo = 0, 239 .pr_slowtimo = 0, 240 .pr_drain = arp_drain, 241 } 242 }; 243 244 245 struct domain arpdomain = { 246 .dom_family = PF_ARP, 247 .dom_name = "arp", 248 .dom_protosw = arpsw, 249 .dom_protoswNPROTOSW = &arpsw[__arraycount(arpsw)], 250 }; 251 252 /* 253 * ARP table locking. 254 * 255 * to prevent lossage vs. the arp_drain routine (which may be called at 256 * any time, including in a device driver context), we do two things: 257 * 258 * 1) manipulation of la->la_hold is done at splnet() (for all of 259 * about two instructions). 260 * 261 * 2) manipulation of the arp table's linked list is done under the 262 * protection of the ARP_LOCK; if arp_drain() or arptimer is called 263 * while the arp table is locked, we punt and try again later. 264 */ 265 266 static int arp_locked; 267 static inline int arp_lock_try(int); 268 static inline void arp_unlock(void); 269 270 static inline int 271 arp_lock_try(int recurse) 272 { 273 int s; 274 275 /* 276 * Use splvm() -- we're blocking things that would cause 277 * mbuf allocation. 278 */ 279 s = splvm(); 280 if (!recurse && arp_locked) { 281 splx(s); 282 return 0; 283 } 284 arp_locked++; 285 splx(s); 286 return 1; 287 } 288 289 static inline void 290 arp_unlock(void) 291 { 292 int s; 293 294 s = splvm(); 295 arp_locked--; 296 splx(s); 297 } 298 299 #ifdef DIAGNOSTIC 300 #define ARP_LOCK(recurse) \ 301 do { \ 302 if (arp_lock_try(recurse) == 0) { \ 303 printf("%s:%d: arp already locked\n", __FILE__, __LINE__); \ 304 panic("arp_lock"); \ 305 } \ 306 } while (/*CONSTCOND*/ 0) 307 #define ARP_LOCK_CHECK() \ 308 do { \ 309 if (arp_locked == 0) { \ 310 printf("%s:%d: arp lock not held\n", __FILE__, __LINE__); \ 311 panic("arp lock check"); \ 312 } \ 313 } while (/*CONSTCOND*/ 0) 314 #else 315 #define ARP_LOCK(x) (void) arp_lock_try(x) 316 #define ARP_LOCK_CHECK() /* nothing */ 317 #endif 318 319 #define ARP_UNLOCK() arp_unlock() 320 321 static void sysctl_net_inet_arp_setup(struct sysctllog **); 322 323 void 324 arp_init(void) 325 { 326 327 sysctl_net_inet_arp_setup(NULL); 328 arpstat_percpu = percpu_alloc(sizeof(uint64_t) * ARP_NSTATS); 329 } 330 331 /* 332 * ARP protocol drain routine. Called when memory is in short supply. 333 * Called at splvm(); don't acquire softnet_lock as can be called from 334 * hardware interrupt handlers. 335 */ 336 void 337 arp_drain(void) 338 { 339 struct llinfo_arp *la, *nla; 340 int count = 0; 341 struct mbuf *mold; 342 343 KERNEL_LOCK(1, NULL); 344 345 if (arp_lock_try(0) == 0) { 346 KERNEL_UNLOCK_ONE(NULL); 347 return; 348 } 349 350 for (la = LIST_FIRST(&llinfo_arp); la != NULL; la = nla) { 351 nla = LIST_NEXT(la, la_list); 352 353 mold = la->la_hold; 354 la->la_hold = 0; 355 356 if (mold) { 357 m_freem(mold); 358 count++; 359 } 360 } 361 ARP_UNLOCK(); 362 ARP_STATADD(ARP_STAT_DFRDROPPED, count); 363 KERNEL_UNLOCK_ONE(NULL); 364 } 365 366 367 /* 368 * Timeout routine. Age arp_tab entries periodically. 369 */ 370 /* ARGSUSED */ 371 static void 372 arptimer(void *arg) 373 { 374 struct llinfo_arp *la, *nla; 375 376 mutex_enter(softnet_lock); 377 KERNEL_LOCK(1, NULL); 378 379 if (arp_lock_try(0) == 0) { 380 /* get it later.. */ 381 KERNEL_UNLOCK_ONE(NULL); 382 mutex_exit(softnet_lock); 383 return; 384 } 385 386 callout_reset(&arptimer_ch, arpt_prune * hz, arptimer, NULL); 387 for (la = LIST_FIRST(&llinfo_arp); la != NULL; la = nla) { 388 struct rtentry *rt = la->la_rt; 389 390 nla = LIST_NEXT(la, la_list); 391 if (rt->rt_expire == 0) 392 continue; 393 if ((rt->rt_expire - time_second) < arpt_refresh && 394 rt->rt_pksent > (time_second - arpt_keep)) { 395 /* 396 * If the entry has been used during since last 397 * refresh, try to renew it before deleting. 398 */ 399 arprequest(rt->rt_ifp, 400 &satocsin(rt->rt_ifa->ifa_addr)->sin_addr, 401 &satocsin(rt_getkey(rt))->sin_addr, 402 CLLADDR(rt->rt_ifp->if_sadl)); 403 } else if (rt->rt_expire <= time_second) 404 arptfree(la); /* timer has expired; clear */ 405 } 406 407 ARP_UNLOCK(); 408 409 KERNEL_UNLOCK_ONE(NULL); 410 mutex_exit(softnet_lock); 411 } 412 413 /* 414 * We set the gateway for RTF_CLONING routes to a "prototype" 415 * link-layer sockaddr whose interface type (if_type) and interface 416 * index (if_index) fields are prepared. 417 */ 418 static struct sockaddr * 419 arp_setgate(struct rtentry *rt, struct sockaddr *gate, 420 const struct sockaddr *netmask) 421 { 422 const struct ifnet *ifp = rt->rt_ifp; 423 uint8_t namelen = strlen(ifp->if_xname); 424 uint8_t addrlen = ifp->if_addrlen; 425 426 /* 427 * XXX: If this is a manually added route to interface 428 * such as older version of routed or gated might provide, 429 * restore cloning bit. 430 */ 431 if ((rt->rt_flags & RTF_HOST) == 0 && netmask != NULL && 432 satocsin(netmask)->sin_addr.s_addr != 0xffffffff) 433 rt->rt_flags |= RTF_CLONING; 434 if (rt->rt_flags & RTF_CLONING) { 435 union { 436 struct sockaddr sa; 437 struct sockaddr_storage ss; 438 struct sockaddr_dl sdl; 439 } u; 440 /* 441 * Case 1: This route should come from a route to iface. 442 */ 443 sockaddr_dl_init(&u.sdl, sizeof(u.ss), 444 ifp->if_index, ifp->if_type, NULL, namelen, NULL, addrlen); 445 rt_setgate(rt, &u.sa); 446 gate = rt->rt_gateway; 447 } 448 return gate; 449 } 450 451 /* 452 * Parallel to llc_rtrequest. 453 */ 454 void 455 arp_rtrequest(int req, struct rtentry *rt, const struct rt_addrinfo *info) 456 { 457 struct sockaddr *gate = rt->rt_gateway; 458 struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo; 459 size_t allocsize; 460 struct mbuf *mold; 461 int s; 462 struct in_ifaddr *ia; 463 struct ifaddr *ifa; 464 struct ifnet *ifp = rt->rt_ifp; 465 466 if (!arpinit_done) { 467 arpinit_done = 1; 468 /* 469 * We generate expiration times from time_second 470 * so avoid accidentally creating permanent routes. 471 */ 472 if (time_second == 0) { 473 struct timespec ts; 474 ts.tv_sec = 1; 475 ts.tv_nsec = 0; 476 tc_setclock(&ts); 477 } 478 callout_init(&arptimer_ch, CALLOUT_MPSAFE); 479 callout_reset(&arptimer_ch, hz, arptimer, NULL); 480 } 481 482 if (req == RTM_LLINFO_UPD) { 483 struct in_addr *in; 484 485 if ((ifa = info->rti_ifa) == NULL) 486 return; 487 488 in = &ifatoia(ifa)->ia_addr.sin_addr; 489 490 arprequest(ifa->ifa_ifp, in, in, 491 CLLADDR(ifa->ifa_ifp->if_sadl)); 492 return; 493 } 494 495 if ((rt->rt_flags & RTF_GATEWAY) != 0) { 496 if (req != RTM_ADD) 497 return; 498 499 /* 500 * linklayers with particular link MTU limitation. 501 */ 502 switch(ifp->if_type) { 503 #if NFDDI > 0 504 case IFT_FDDI: 505 if (ifp->if_mtu > FDDIIPMTU) 506 rt->rt_rmx.rmx_mtu = FDDIIPMTU; 507 break; 508 #endif 509 #if NARC > 0 510 case IFT_ARCNET: 511 { 512 int arcipifmtu; 513 514 if (ifp->if_flags & IFF_LINK0) 515 arcipifmtu = arc_ipmtu; 516 else 517 arcipifmtu = ARCMTU; 518 if (ifp->if_mtu > arcipifmtu) 519 rt->rt_rmx.rmx_mtu = arcipifmtu; 520 break; 521 } 522 #endif 523 } 524 return; 525 } 526 527 ARP_LOCK(1); /* we may already be locked here. */ 528 529 switch (req) { 530 case RTM_SETGATE: 531 gate = arp_setgate(rt, gate, info->rti_info[RTAX_NETMASK]); 532 break; 533 case RTM_ADD: 534 gate = arp_setgate(rt, gate, info->rti_info[RTAX_NETMASK]); 535 if (rt->rt_flags & RTF_CLONING) { 536 /* 537 * Give this route an expiration time, even though 538 * it's a "permanent" route, so that routes cloned 539 * from it do not need their expiration time set. 540 */ 541 rt->rt_expire = time_second; 542 /* 543 * linklayers with particular link MTU limitation. 544 */ 545 switch (ifp->if_type) { 546 #if NFDDI > 0 547 case IFT_FDDI: 548 if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0 && 549 (rt->rt_rmx.rmx_mtu > FDDIIPMTU || 550 (rt->rt_rmx.rmx_mtu == 0 && 551 ifp->if_mtu > FDDIIPMTU))) 552 rt->rt_rmx.rmx_mtu = FDDIIPMTU; 553 break; 554 #endif 555 #if NARC > 0 556 case IFT_ARCNET: 557 { 558 int arcipifmtu; 559 if (ifp->if_flags & IFF_LINK0) 560 arcipifmtu = arc_ipmtu; 561 else 562 arcipifmtu = ARCMTU; 563 564 if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0 && 565 (rt->rt_rmx.rmx_mtu > arcipifmtu || 566 (rt->rt_rmx.rmx_mtu == 0 && 567 ifp->if_mtu > arcipifmtu))) 568 rt->rt_rmx.rmx_mtu = arcipifmtu; 569 break; 570 } 571 #endif 572 } 573 break; 574 } 575 /* Announce a new entry if requested. */ 576 if (rt->rt_flags & RTF_ANNOUNCE) { 577 arprequest(ifp, 578 &satocsin(rt_getkey(rt))->sin_addr, 579 &satocsin(rt_getkey(rt))->sin_addr, 580 CLLADDR(satocsdl(gate))); 581 } 582 /*FALLTHROUGH*/ 583 case RTM_RESOLVE: 584 if (gate->sa_family != AF_LINK || 585 gate->sa_len < sockaddr_dl_measure(0, ifp->if_addrlen)) { 586 log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n"); 587 break; 588 } 589 satosdl(gate)->sdl_type = ifp->if_type; 590 satosdl(gate)->sdl_index = ifp->if_index; 591 if (la != NULL) 592 break; /* This happens on a route change */ 593 /* 594 * Case 2: This route may come from cloning, or a manual route 595 * add with a LL address. 596 */ 597 switch (ifp->if_type) { 598 #if NTOKEN > 0 599 case IFT_ISO88025: 600 allocsize = sizeof(*la) + sizeof(struct token_rif); 601 break; 602 #endif /* NTOKEN > 0 */ 603 default: 604 allocsize = sizeof(*la); 605 } 606 R_Malloc(la, struct llinfo_arp *, allocsize); 607 rt->rt_llinfo = (void *)la; 608 if (la == NULL) { 609 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); 610 break; 611 } 612 arp_inuse++, arp_allocated++; 613 memset(la, 0, allocsize); 614 la->la_rt = rt; 615 rt->rt_flags |= RTF_LLINFO; 616 LIST_INSERT_HEAD(&llinfo_arp, la, la_list); 617 618 INADDR_TO_IA(satocsin(rt_getkey(rt))->sin_addr, ia); 619 while (ia && ia->ia_ifp != ifp) 620 NEXT_IA_WITH_SAME_ADDR(ia); 621 if (ia) { 622 /* 623 * This test used to be 624 * if (lo0ifp->if_flags & IFF_UP) 625 * It allowed local traffic to be forced through 626 * the hardware by configuring the loopback down. 627 * However, it causes problems during network 628 * configuration for boards that can't receive 629 * packets they send. It is now necessary to clear 630 * "useloopback" and remove the route to force 631 * traffic out to the hardware. 632 * 633 * In 4.4BSD, the above "if" statement checked 634 * rt->rt_ifa against rt_getkey(rt). It was changed 635 * to the current form so that we can provide a 636 * better support for multiple IPv4 addresses on a 637 * interface. 638 */ 639 rt->rt_expire = 0; 640 if (sockaddr_dl_init(satosdl(gate), gate->sa_len, 641 ifp->if_index, ifp->if_type, NULL, 0, 642 CLLADDR(ifp->if_sadl), ifp->if_addrlen) == NULL) { 643 panic("%s(%s): sockaddr_dl_init cannot fail", 644 __func__, ifp->if_xname); 645 } 646 if (useloopback) 647 ifp = rt->rt_ifp = lo0ifp; 648 /* 649 * make sure to set rt->rt_ifa to the interface 650 * address we are using, otherwise we will have trouble 651 * with source address selection. 652 */ 653 ifa = &ia->ia_ifa; 654 if (ifa != rt->rt_ifa) 655 rt_replace_ifa(rt, ifa); 656 } 657 break; 658 659 case RTM_DELETE: 660 if (la == NULL) 661 break; 662 arp_inuse--; 663 LIST_REMOVE(la, la_list); 664 rt->rt_llinfo = NULL; 665 rt->rt_flags &= ~RTF_LLINFO; 666 667 s = splnet(); 668 mold = la->la_hold; 669 la->la_hold = 0; 670 splx(s); 671 672 if (mold) 673 m_freem(mold); 674 675 Free((void *)la); 676 } 677 ARP_UNLOCK(); 678 } 679 680 /* 681 * Broadcast an ARP request. Caller specifies: 682 * - arp header source ip address 683 * - arp header target ip address 684 * - arp header source ethernet address 685 */ 686 void 687 arprequest(struct ifnet *ifp, 688 const struct in_addr *sip, const struct in_addr *tip, 689 const u_int8_t *enaddr) 690 { 691 struct mbuf *m; 692 struct arphdr *ah; 693 struct sockaddr sa; 694 uint64_t *arps; 695 696 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 697 return; 698 MCLAIM(m, &arpdomain.dom_mowner); 699 switch (ifp->if_type) { 700 case IFT_IEEE1394: 701 m->m_len = sizeof(*ah) + 2 * sizeof(struct in_addr) + 702 ifp->if_addrlen; 703 break; 704 default: 705 m->m_len = sizeof(*ah) + 2 * sizeof(struct in_addr) + 706 2 * ifp->if_addrlen; 707 break; 708 } 709 m->m_pkthdr.len = m->m_len; 710 MH_ALIGN(m, m->m_len); 711 ah = mtod(m, struct arphdr *); 712 memset(ah, 0, m->m_len); 713 switch (ifp->if_type) { 714 case IFT_IEEE1394: /* RFC2734 */ 715 /* fill it now for ar_tpa computation */ 716 ah->ar_hrd = htons(ARPHRD_IEEE1394); 717 break; 718 default: 719 /* ifp->if_output will fill ar_hrd */ 720 break; 721 } 722 ah->ar_pro = htons(ETHERTYPE_IP); 723 ah->ar_hln = ifp->if_addrlen; /* hardware address length */ 724 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 725 ah->ar_op = htons(ARPOP_REQUEST); 726 memcpy(ar_sha(ah), enaddr, ah->ar_hln); 727 memcpy(ar_spa(ah), sip, ah->ar_pln); 728 memcpy(ar_tpa(ah), tip, ah->ar_pln); 729 sa.sa_family = AF_ARP; 730 sa.sa_len = 2; 731 m->m_flags |= M_BCAST; 732 arps = ARP_STAT_GETREF(); 733 arps[ARP_STAT_SNDTOTAL]++; 734 arps[ARP_STAT_SENDREQUEST]++; 735 ARP_STAT_PUTREF(); 736 (*ifp->if_output)(ifp, m, &sa, NULL); 737 } 738 739 /* 740 * Resolve an IP address into an ethernet address. If success, 741 * desten is filled in. If there is no entry in arptab, 742 * set one up and broadcast a request for the IP address. 743 * Hold onto this mbuf and resend it once the address 744 * is finally resolved. A return value of 1 indicates 745 * that desten has been filled in and the packet should be sent 746 * normally; a 0 return indicates that the packet has been 747 * taken over here, either now or for later transmission. 748 */ 749 int 750 arpresolve(struct ifnet *ifp, struct rtentry *rt, struct mbuf *m, 751 const struct sockaddr *dst, u_char *desten) 752 { 753 struct llinfo_arp *la; 754 const struct sockaddr_dl *sdl; 755 struct mbuf *mold; 756 int s; 757 758 if ((la = arplookup1(m, &satocsin(dst)->sin_addr, 1, 0, rt)) != NULL) 759 rt = la->la_rt; 760 761 if (la == NULL || rt == NULL) { 762 ARP_STATINC(ARP_STAT_ALLOCFAIL); 763 log(LOG_DEBUG, 764 "arpresolve: can't allocate llinfo on %s for %s\n", 765 ifp->if_xname, in_fmtaddr(satocsin(dst)->sin_addr)); 766 m_freem(m); 767 return 0; 768 } 769 sdl = satocsdl(rt->rt_gateway); 770 /* 771 * Check the address family and length is valid, the address 772 * is resolved; otherwise, try to resolve. 773 */ 774 if ((rt->rt_expire == 0 || rt->rt_expire > time_second) && 775 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 776 memcpy(desten, CLLADDR(sdl), 777 min(sdl->sdl_alen, ifp->if_addrlen)); 778 rt->rt_pksent = time_second; /* Time for last pkt sent */ 779 return 1; 780 } 781 /* 782 * There is an arptab entry, but no ethernet address 783 * response yet. Replace the held mbuf with this 784 * latest one. 785 */ 786 787 ARP_STATINC(ARP_STAT_DFRTOTAL); 788 s = splnet(); 789 mold = la->la_hold; 790 la->la_hold = m; 791 splx(s); 792 793 if (mold) { 794 ARP_STATINC(ARP_STAT_DFRDROPPED); 795 m_freem(mold); 796 } 797 798 /* 799 * Re-send the ARP request when appropriate. 800 */ 801 #ifdef DIAGNOSTIC 802 if (rt->rt_expire == 0) { 803 /* This should never happen. (Should it? -gwr) */ 804 printf("arpresolve: unresolved and rt_expire == 0\n"); 805 /* Set expiration time to now (expired). */ 806 rt->rt_expire = time_second; 807 } 808 #endif 809 if (rt->rt_expire) { 810 rt->rt_flags &= ~RTF_REJECT; 811 if (la->la_asked == 0 || rt->rt_expire != time_second) { 812 rt->rt_expire = time_second; 813 if (la->la_asked++ < arp_maxtries) { 814 arprequest(ifp, 815 &satocsin(rt->rt_ifa->ifa_addr)->sin_addr, 816 &satocsin(dst)->sin_addr, 817 #if NCARP > 0 818 (rt->rt_ifp->if_type == IFT_CARP) ? 819 CLLADDR(rt->rt_ifp->if_sadl): 820 #endif 821 CLLADDR(ifp->if_sadl)); 822 } else { 823 rt->rt_flags |= RTF_REJECT; 824 rt->rt_expire += arpt_down; 825 la->la_asked = 0; 826 } 827 } 828 } 829 return 0; 830 } 831 832 /* 833 * Common length and type checks are done here, 834 * then the protocol-specific routine is called. 835 */ 836 void 837 arpintr(void) 838 { 839 struct mbuf *m; 840 struct arphdr *ar; 841 int s; 842 int arplen; 843 844 mutex_enter(softnet_lock); 845 KERNEL_LOCK(1, NULL); 846 while (arpintrq.ifq_head) { 847 s = splnet(); 848 IF_DEQUEUE(&arpintrq, m); 849 splx(s); 850 if (m == 0 || (m->m_flags & M_PKTHDR) == 0) 851 panic("arpintr"); 852 853 MCLAIM(m, &arpdomain.dom_mowner); 854 ARP_STATINC(ARP_STAT_RCVTOTAL); 855 856 /* 857 * First, make sure we have at least struct arphdr. 858 */ 859 if (m->m_len < sizeof(struct arphdr) || 860 (ar = mtod(m, struct arphdr *)) == NULL) 861 goto badlen; 862 863 switch (m->m_pkthdr.rcvif->if_type) { 864 case IFT_IEEE1394: 865 arplen = sizeof(struct arphdr) + 866 ar->ar_hln + 2 * ar->ar_pln; 867 break; 868 default: 869 arplen = sizeof(struct arphdr) + 870 2 * ar->ar_hln + 2 * ar->ar_pln; 871 break; 872 } 873 874 if (/* XXX ntohs(ar->ar_hrd) == ARPHRD_ETHER && */ 875 m->m_len >= arplen) 876 switch (ntohs(ar->ar_pro)) { 877 case ETHERTYPE_IP: 878 case ETHERTYPE_IPTRAILERS: 879 in_arpinput(m); 880 continue; 881 default: 882 ARP_STATINC(ARP_STAT_RCVBADPROTO); 883 } 884 else { 885 badlen: 886 ARP_STATINC(ARP_STAT_RCVBADLEN); 887 } 888 m_freem(m); 889 } 890 KERNEL_UNLOCK_ONE(NULL); 891 mutex_exit(softnet_lock); 892 } 893 894 /* 895 * ARP for Internet protocols on 10 Mb/s Ethernet. 896 * Algorithm is that given in RFC 826. 897 * In addition, a sanity check is performed on the sender 898 * protocol address, to catch impersonators. 899 * We no longer handle negotiations for use of trailer protocol: 900 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 901 * along with IP replies if we wanted trailers sent to us, 902 * and also sent them in response to IP replies. 903 * This allowed either end to announce the desire to receive 904 * trailer packets. 905 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 906 * but formerly didn't normally send requests. 907 */ 908 static void 909 in_arpinput(struct mbuf *m) 910 { 911 struct arphdr *ah; 912 struct ifnet *ifp = m->m_pkthdr.rcvif; 913 struct llinfo_arp *la = NULL; 914 struct rtentry *rt; 915 struct in_ifaddr *ia; 916 #if NBRIDGE > 0 917 struct in_ifaddr *bridge_ia = NULL; 918 #endif 919 #if NCARP > 0 920 u_int32_t count = 0, index = 0; 921 #endif 922 struct sockaddr_dl *sdl; 923 struct sockaddr sa; 924 struct in_addr isaddr, itaddr, myaddr; 925 int op; 926 struct mbuf *mold; 927 void *tha; 928 int s; 929 uint64_t *arps; 930 931 if (__predict_false(m_makewritable(&m, 0, m->m_pkthdr.len, M_DONTWAIT))) 932 goto out; 933 ah = mtod(m, struct arphdr *); 934 op = ntohs(ah->ar_op); 935 936 /* 937 * Fix up ah->ar_hrd if necessary, before using ar_tha() or 938 * ar_tpa(). 939 */ 940 switch (ifp->if_type) { 941 case IFT_IEEE1394: 942 if (ntohs(ah->ar_hrd) == ARPHRD_IEEE1394) 943 ; 944 else { 945 /* XXX this is to make sure we compute ar_tha right */ 946 /* XXX check ar_hrd more strictly? */ 947 ah->ar_hrd = htons(ARPHRD_IEEE1394); 948 } 949 break; 950 default: 951 /* XXX check ar_hrd? */ 952 break; 953 } 954 955 memcpy(&isaddr, ar_spa(ah), sizeof (isaddr)); 956 memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr)); 957 958 if (m->m_flags & (M_BCAST|M_MCAST)) 959 ARP_STATINC(ARP_STAT_RCVMCAST); 960 961 /* 962 * If the target IP address is zero, ignore the packet. 963 * This prevents the code below from tring to answer 964 * when we are using IP address zero (booting). 965 */ 966 if (in_nullhost(itaddr)) { 967 ARP_STATINC(ARP_STAT_RCVZEROTPA); 968 goto out; 969 } 970 971 /* 972 * If the source IP address is zero, this is most likely a 973 * confused host trying to use IP address zero. (Windoze?) 974 * XXX: Should we bother trying to reply to these? 975 */ 976 if (in_nullhost(isaddr)) { 977 ARP_STATINC(ARP_STAT_RCVZEROSPA); 978 goto out; 979 } 980 981 /* 982 * Search for a matching interface address 983 * or any address on the interface to use 984 * as a dummy address in the rest of this function 985 */ 986 987 INADDR_TO_IA(itaddr, ia); 988 while (ia != NULL) { 989 #if NCARP > 0 990 if (ia->ia_ifp->if_type == IFT_CARP && 991 ((ia->ia_ifp->if_flags & (IFF_UP|IFF_RUNNING)) == 992 (IFF_UP|IFF_RUNNING))) { 993 index++; 994 if (ia->ia_ifp == m->m_pkthdr.rcvif && 995 carp_iamatch(ia, ar_sha(ah), 996 &count, index)) { 997 break; 998 } 999 } else 1000 #endif 1001 if (ia->ia_ifp == m->m_pkthdr.rcvif) 1002 break; 1003 #if NBRIDGE > 0 1004 /* 1005 * If the interface we received the packet on 1006 * is part of a bridge, check to see if we need 1007 * to "bridge" the packet to ourselves at this 1008 * layer. Note we still prefer a perfect match, 1009 * but allow this weaker match if necessary. 1010 */ 1011 if (m->m_pkthdr.rcvif->if_bridge != NULL && 1012 m->m_pkthdr.rcvif->if_bridge == ia->ia_ifp->if_bridge) 1013 bridge_ia = ia; 1014 #endif /* NBRIDGE > 0 */ 1015 1016 NEXT_IA_WITH_SAME_ADDR(ia); 1017 } 1018 1019 #if NBRIDGE > 0 1020 if (ia == NULL && bridge_ia != NULL) { 1021 ia = bridge_ia; 1022 ifp = bridge_ia->ia_ifp; 1023 } 1024 #endif 1025 1026 if (ia == NULL) { 1027 INADDR_TO_IA(isaddr, ia); 1028 while ((ia != NULL) && ia->ia_ifp != m->m_pkthdr.rcvif) 1029 NEXT_IA_WITH_SAME_ADDR(ia); 1030 1031 if (ia == NULL) { 1032 IFP_TO_IA(ifp, ia); 1033 if (ia == NULL) { 1034 ARP_STATINC(ARP_STAT_RCVNOINT); 1035 goto out; 1036 } 1037 } 1038 } 1039 1040 myaddr = ia->ia_addr.sin_addr; 1041 1042 /* XXX checks for bridge case? */ 1043 if (!memcmp(ar_sha(ah), CLLADDR(ifp->if_sadl), ifp->if_addrlen)) { 1044 ARP_STATINC(ARP_STAT_RCVLOCALSHA); 1045 goto out; /* it's from me, ignore it. */ 1046 } 1047 1048 /* XXX checks for bridge case? */ 1049 if (!memcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) { 1050 ARP_STATINC(ARP_STAT_RCVBCASTSHA); 1051 log(LOG_ERR, 1052 "%s: arp: link address is broadcast for IP address %s!\n", 1053 ifp->if_xname, in_fmtaddr(isaddr)); 1054 goto out; 1055 } 1056 1057 if (in_hosteq(isaddr, myaddr)) { 1058 ARP_STATINC(ARP_STAT_RCVLOCALSPA); 1059 log(LOG_ERR, 1060 "duplicate IP address %s sent from link address %s\n", 1061 in_fmtaddr(isaddr), lla_snprintf(ar_sha(ah), ah->ar_hln)); 1062 itaddr = myaddr; 1063 goto reply; 1064 } 1065 la = arplookup(m, &isaddr, in_hosteq(itaddr, myaddr), 0); 1066 if (la != NULL && (rt = la->la_rt) && (sdl = satosdl(rt->rt_gateway))) { 1067 if (sdl->sdl_alen && 1068 memcmp(ar_sha(ah), CLLADDR(sdl), sdl->sdl_alen)) { 1069 if (rt->rt_flags & RTF_STATIC) { 1070 ARP_STATINC(ARP_STAT_RCVOVERPERM); 1071 log(LOG_INFO, 1072 "%s tried to overwrite permanent arp info" 1073 " for %s\n", 1074 lla_snprintf(ar_sha(ah), ah->ar_hln), 1075 in_fmtaddr(isaddr)); 1076 goto out; 1077 } else if (rt->rt_ifp != ifp) { 1078 ARP_STATINC(ARP_STAT_RCVOVERINT); 1079 log(LOG_INFO, 1080 "%s on %s tried to overwrite " 1081 "arp info for %s on %s\n", 1082 lla_snprintf(ar_sha(ah), ah->ar_hln), 1083 ifp->if_xname, in_fmtaddr(isaddr), 1084 rt->rt_ifp->if_xname); 1085 goto out; 1086 } else { 1087 ARP_STATINC(ARP_STAT_RCVOVER); 1088 log(LOG_INFO, 1089 "arp info overwritten for %s by %s\n", 1090 in_fmtaddr(isaddr), 1091 lla_snprintf(ar_sha(ah), ah->ar_hln)); 1092 } 1093 } 1094 /* 1095 * sanity check for the address length. 1096 * XXX this does not work for protocols with variable address 1097 * length. -is 1098 */ 1099 if (sdl->sdl_alen && 1100 sdl->sdl_alen != ah->ar_hln) { 1101 ARP_STATINC(ARP_STAT_RCVLENCHG); 1102 log(LOG_WARNING, 1103 "arp from %s: new addr len %d, was %d\n", 1104 in_fmtaddr(isaddr), ah->ar_hln, sdl->sdl_alen); 1105 } 1106 if (ifp->if_addrlen != ah->ar_hln) { 1107 ARP_STATINC(ARP_STAT_RCVBADLEN); 1108 log(LOG_WARNING, 1109 "arp from %s: addr len: new %d, i/f %d (ignored)\n", 1110 in_fmtaddr(isaddr), ah->ar_hln, 1111 ifp->if_addrlen); 1112 goto reply; 1113 } 1114 #if NTOKEN > 0 1115 /* 1116 * XXX uses m_data and assumes the complete answer including 1117 * XXX token-ring headers is in the same buf 1118 */ 1119 if (ifp->if_type == IFT_ISO88025) { 1120 struct token_header *trh; 1121 1122 trh = (struct token_header *)M_TRHSTART(m); 1123 if (trh->token_shost[0] & TOKEN_RI_PRESENT) { 1124 struct token_rif *rif; 1125 size_t riflen; 1126 1127 rif = TOKEN_RIF(trh); 1128 riflen = (ntohs(rif->tr_rcf) & 1129 TOKEN_RCF_LEN_MASK) >> 8; 1130 1131 if (riflen > 2 && 1132 riflen < sizeof(struct token_rif) && 1133 (riflen & 1) == 0) { 1134 rif->tr_rcf ^= htons(TOKEN_RCF_DIRECTION); 1135 rif->tr_rcf &= htons(~TOKEN_RCF_BROADCAST_MASK); 1136 memcpy(TOKEN_RIF(la), rif, riflen); 1137 } 1138 } 1139 } 1140 #endif /* NTOKEN > 0 */ 1141 (void)sockaddr_dl_setaddr(sdl, sdl->sdl_len, ar_sha(ah), 1142 ah->ar_hln); 1143 if (rt->rt_expire) 1144 rt->rt_expire = time_second + arpt_keep; 1145 rt->rt_flags &= ~RTF_REJECT; 1146 la->la_asked = 0; 1147 1148 s = splnet(); 1149 mold = la->la_hold; 1150 la->la_hold = 0; 1151 splx(s); 1152 1153 if (mold) { 1154 ARP_STATINC(ARP_STAT_DFRSENT); 1155 (*ifp->if_output)(ifp, mold, rt_getkey(rt), rt); 1156 } 1157 } 1158 reply: 1159 if (op != ARPOP_REQUEST) { 1160 if (op == ARPOP_REPLY) 1161 ARP_STATINC(ARP_STAT_RCVREPLY); 1162 out: 1163 m_freem(m); 1164 return; 1165 } 1166 ARP_STATINC(ARP_STAT_RCVREQUEST); 1167 if (in_hosteq(itaddr, myaddr)) { 1168 /* I am the target */ 1169 tha = ar_tha(ah); 1170 if (tha) 1171 memcpy(tha, ar_sha(ah), ah->ar_hln); 1172 memcpy(ar_sha(ah), CLLADDR(ifp->if_sadl), ah->ar_hln); 1173 } else { 1174 la = arplookup(m, &itaddr, 0, SIN_PROXY); 1175 if (la == NULL) 1176 goto out; 1177 rt = la->la_rt; 1178 if (rt->rt_ifp->if_type == IFT_CARP && 1179 m->m_pkthdr.rcvif->if_type != IFT_CARP) 1180 goto out; 1181 tha = ar_tha(ah); 1182 if (tha) 1183 memcpy(tha, ar_sha(ah), ah->ar_hln); 1184 sdl = satosdl(rt->rt_gateway); 1185 memcpy(ar_sha(ah), CLLADDR(sdl), ah->ar_hln); 1186 } 1187 1188 memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln); 1189 memcpy(ar_spa(ah), &itaddr, ah->ar_pln); 1190 ah->ar_op = htons(ARPOP_REPLY); 1191 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 1192 switch (ifp->if_type) { 1193 case IFT_IEEE1394: 1194 /* 1195 * ieee1394 arp reply is broadcast 1196 */ 1197 m->m_flags &= ~M_MCAST; 1198 m->m_flags |= M_BCAST; 1199 m->m_len = sizeof(*ah) + (2 * ah->ar_pln) + ah->ar_hln; 1200 break; 1201 1202 default: 1203 m->m_flags &= ~(M_BCAST|M_MCAST); /* never reply by broadcast */ 1204 m->m_len = sizeof(*ah) + (2 * ah->ar_pln) + (2 * ah->ar_hln); 1205 break; 1206 } 1207 m->m_pkthdr.len = m->m_len; 1208 sa.sa_family = AF_ARP; 1209 sa.sa_len = 2; 1210 arps = ARP_STAT_GETREF(); 1211 arps[ARP_STAT_SNDTOTAL]++; 1212 arps[ARP_STAT_SNDREPLY]++; 1213 ARP_STAT_PUTREF(); 1214 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 1215 return; 1216 } 1217 1218 /* 1219 * Free an arp entry. 1220 */ 1221 static void arptfree(struct llinfo_arp *la) 1222 { 1223 struct rtentry *rt = la->la_rt; 1224 struct sockaddr_dl *sdl; 1225 1226 ARP_LOCK_CHECK(); 1227 1228 if (rt == NULL) 1229 panic("arptfree"); 1230 if (rt->rt_refcnt > 0 && (sdl = satosdl(rt->rt_gateway)) && 1231 sdl->sdl_family == AF_LINK) { 1232 sdl->sdl_alen = 0; 1233 la->la_asked = 0; 1234 rt->rt_flags &= ~RTF_REJECT; 1235 return; 1236 } 1237 rtrequest(RTM_DELETE, rt_getkey(rt), NULL, rt_mask(rt), 0, NULL); 1238 } 1239 1240 static struct llinfo_arp * 1241 arplookup(struct mbuf *m, const struct in_addr *addr, int create, int proxy) 1242 { 1243 return arplookup1(m, addr, create, proxy, NULL); 1244 } 1245 1246 /* 1247 * Lookup or enter a new address in arptab. 1248 */ 1249 static struct llinfo_arp * 1250 arplookup1(struct mbuf *m, const struct in_addr *addr, int create, int proxy, 1251 struct rtentry *rt0) 1252 { 1253 struct arphdr *ah; 1254 struct ifnet *ifp = m->m_pkthdr.rcvif; 1255 struct rtentry *rt; 1256 struct sockaddr_inarp sin; 1257 const char *why = NULL; 1258 1259 ah = mtod(m, struct arphdr *); 1260 if (rt0 == NULL) { 1261 memset(&sin, 0, sizeof(sin)); 1262 sin.sin_len = sizeof(sin); 1263 sin.sin_family = AF_INET; 1264 sin.sin_addr = *addr; 1265 sin.sin_other = proxy ? SIN_PROXY : 0; 1266 rt = rtalloc1(sintosa(&sin), create); 1267 if (rt == NULL) 1268 return NULL; 1269 rt->rt_refcnt--; 1270 } else 1271 rt = rt0; 1272 1273 #define IS_LLINFO(__rt) \ 1274 (((__rt)->rt_flags & (RTF_GATEWAY | RTF_LLINFO)) == RTF_LLINFO && \ 1275 (__rt)->rt_gateway->sa_family == AF_LINK) 1276 1277 1278 if (IS_LLINFO(rt)) 1279 return (struct llinfo_arp *)rt->rt_llinfo; 1280 1281 if (create) { 1282 if (rt->rt_flags & RTF_GATEWAY) 1283 why = "host is not on local network"; 1284 else if ((rt->rt_flags & RTF_LLINFO) == 0) { 1285 ARP_STATINC(ARP_STAT_ALLOCFAIL); 1286 why = "could not allocate llinfo"; 1287 } else 1288 why = "gateway route is not ours"; 1289 log(LOG_DEBUG, "arplookup: unable to enter address" 1290 " for %s@%s on %s (%s)\n", 1291 in_fmtaddr(*addr), lla_snprintf(ar_sha(ah), ah->ar_hln), 1292 (ifp) ? ifp->if_xname : "null", why); 1293 if (rt->rt_refcnt <= 0 && (rt->rt_flags & RTF_CLONED) != 0) { 1294 rtrequest(RTM_DELETE, rt_getkey(rt), 1295 rt->rt_gateway, rt_mask(rt), rt->rt_flags, NULL); 1296 } 1297 } 1298 return NULL; 1299 } 1300 1301 int 1302 arpioctl(u_long cmd, void *data) 1303 { 1304 1305 return EOPNOTSUPP; 1306 } 1307 1308 void 1309 arp_ifinit(struct ifnet *ifp, struct ifaddr *ifa) 1310 { 1311 struct in_addr *ip; 1312 1313 /* 1314 * Warn the user if another station has this IP address, 1315 * but only if the interface IP address is not zero. 1316 */ 1317 ip = &IA_SIN(ifa)->sin_addr; 1318 if (!in_nullhost(*ip)) 1319 arprequest(ifp, ip, ip, CLLADDR(ifp->if_sadl)); 1320 1321 ifa->ifa_rtrequest = arp_rtrequest; 1322 ifa->ifa_flags |= RTF_CLONING; 1323 } 1324 1325 /* 1326 * Called from 10 Mb/s Ethernet interrupt handlers 1327 * when ether packet type ETHERTYPE_REVARP 1328 * is received. Common length and type checks are done here, 1329 * then the protocol-specific routine is called. 1330 */ 1331 void 1332 revarpinput(struct mbuf *m) 1333 { 1334 struct arphdr *ar; 1335 1336 if (m->m_len < sizeof(struct arphdr)) 1337 goto out; 1338 ar = mtod(m, struct arphdr *); 1339 #if 0 /* XXX I don't think we need this... and it will prevent other LL */ 1340 if (ntohs(ar->ar_hrd) != ARPHRD_ETHER) 1341 goto out; 1342 #endif 1343 if (m->m_len < sizeof(struct arphdr) + 2 * (ar->ar_hln + ar->ar_pln)) 1344 goto out; 1345 switch (ntohs(ar->ar_pro)) { 1346 case ETHERTYPE_IP: 1347 case ETHERTYPE_IPTRAILERS: 1348 in_revarpinput(m); 1349 return; 1350 1351 default: 1352 break; 1353 } 1354 out: 1355 m_freem(m); 1356 } 1357 1358 /* 1359 * RARP for Internet protocols on 10 Mb/s Ethernet. 1360 * Algorithm is that given in RFC 903. 1361 * We are only using for bootstrap purposes to get an ip address for one of 1362 * our interfaces. Thus we support no user-interface. 1363 * 1364 * Since the contents of the RARP reply are specific to the interface that 1365 * sent the request, this code must ensure that they are properly associated. 1366 * 1367 * Note: also supports ARP via RARP packets, per the RFC. 1368 */ 1369 void 1370 in_revarpinput(struct mbuf *m) 1371 { 1372 struct ifnet *ifp; 1373 struct arphdr *ah; 1374 void *tha; 1375 int op; 1376 1377 ah = mtod(m, struct arphdr *); 1378 op = ntohs(ah->ar_op); 1379 1380 switch (m->m_pkthdr.rcvif->if_type) { 1381 case IFT_IEEE1394: 1382 /* ARP without target hardware address is not supported */ 1383 goto out; 1384 default: 1385 break; 1386 } 1387 1388 switch (op) { 1389 case ARPOP_REQUEST: 1390 case ARPOP_REPLY: /* per RFC */ 1391 in_arpinput(m); 1392 return; 1393 case ARPOP_REVREPLY: 1394 break; 1395 case ARPOP_REVREQUEST: /* handled by rarpd(8) */ 1396 default: 1397 goto out; 1398 } 1399 if (!revarp_in_progress) 1400 goto out; 1401 ifp = m->m_pkthdr.rcvif; 1402 if (ifp != myip_ifp) /* !same interface */ 1403 goto out; 1404 if (myip_initialized) 1405 goto wake; 1406 tha = ar_tha(ah); 1407 KASSERT(tha); 1408 if (memcmp(tha, CLLADDR(ifp->if_sadl), ifp->if_sadl->sdl_alen)) 1409 goto out; 1410 memcpy(&srv_ip, ar_spa(ah), sizeof(srv_ip)); 1411 memcpy(&myip, ar_tpa(ah), sizeof(myip)); 1412 myip_initialized = 1; 1413 wake: /* Do wakeup every time in case it was missed. */ 1414 wakeup((void *)&myip); 1415 1416 out: 1417 m_freem(m); 1418 } 1419 1420 /* 1421 * Send a RARP request for the ip address of the specified interface. 1422 * The request should be RFC 903-compliant. 1423 */ 1424 void 1425 revarprequest(struct ifnet *ifp) 1426 { 1427 struct sockaddr sa; 1428 struct mbuf *m; 1429 struct arphdr *ah; 1430 void *tha; 1431 1432 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 1433 return; 1434 MCLAIM(m, &arpdomain.dom_mowner); 1435 m->m_len = sizeof(*ah) + 2*sizeof(struct in_addr) + 1436 2*ifp->if_addrlen; 1437 m->m_pkthdr.len = m->m_len; 1438 MH_ALIGN(m, m->m_len); 1439 ah = mtod(m, struct arphdr *); 1440 memset(ah, 0, m->m_len); 1441 ah->ar_pro = htons(ETHERTYPE_IP); 1442 ah->ar_hln = ifp->if_addrlen; /* hardware address length */ 1443 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 1444 ah->ar_op = htons(ARPOP_REVREQUEST); 1445 1446 memcpy(ar_sha(ah), CLLADDR(ifp->if_sadl), ah->ar_hln); 1447 tha = ar_tha(ah); 1448 KASSERT(tha); 1449 memcpy(tha, CLLADDR(ifp->if_sadl), ah->ar_hln); 1450 1451 sa.sa_family = AF_ARP; 1452 sa.sa_len = 2; 1453 m->m_flags |= M_BCAST; 1454 (*ifp->if_output)(ifp, m, &sa, NULL); 1455 1456 } 1457 1458 /* 1459 * RARP for the ip address of the specified interface, but also 1460 * save the ip address of the server that sent the answer. 1461 * Timeout if no response is received. 1462 */ 1463 int 1464 revarpwhoarewe(struct ifnet *ifp, struct in_addr *serv_in, 1465 struct in_addr *clnt_in) 1466 { 1467 int result, count = 20; 1468 1469 myip_initialized = 0; 1470 myip_ifp = ifp; 1471 1472 revarp_in_progress = 1; 1473 while (count--) { 1474 revarprequest(ifp); 1475 result = tsleep((void *)&myip, PSOCK, "revarp", hz/2); 1476 if (result != EWOULDBLOCK) 1477 break; 1478 } 1479 revarp_in_progress = 0; 1480 1481 if (!myip_initialized) 1482 return ENETUNREACH; 1483 1484 memcpy(serv_in, &srv_ip, sizeof(*serv_in)); 1485 memcpy(clnt_in, &myip, sizeof(*clnt_in)); 1486 return 0; 1487 } 1488 1489 1490 1491 #ifdef DDB 1492 1493 #include <machine/db_machdep.h> 1494 #include <ddb/db_interface.h> 1495 #include <ddb/db_output.h> 1496 1497 static void 1498 db_print_sa(const struct sockaddr *sa) 1499 { 1500 int len; 1501 const u_char *p; 1502 1503 if (sa == NULL) { 1504 db_printf("[NULL]"); 1505 return; 1506 } 1507 1508 p = (const u_char *)sa; 1509 len = sa->sa_len; 1510 db_printf("["); 1511 while (len > 0) { 1512 db_printf("%d", *p); 1513 p++; len--; 1514 if (len) db_printf(","); 1515 } 1516 db_printf("]\n"); 1517 } 1518 1519 static void 1520 db_print_ifa(struct ifaddr *ifa) 1521 { 1522 if (ifa == NULL) 1523 return; 1524 db_printf(" ifa_addr="); 1525 db_print_sa(ifa->ifa_addr); 1526 db_printf(" ifa_dsta="); 1527 db_print_sa(ifa->ifa_dstaddr); 1528 db_printf(" ifa_mask="); 1529 db_print_sa(ifa->ifa_netmask); 1530 db_printf(" flags=0x%x,refcnt=%d,metric=%d\n", 1531 ifa->ifa_flags, 1532 ifa->ifa_refcnt, 1533 ifa->ifa_metric); 1534 } 1535 1536 static void 1537 db_print_llinfo(void *li) 1538 { 1539 struct llinfo_arp *la; 1540 1541 if (li == NULL) 1542 return; 1543 la = (struct llinfo_arp *)li; 1544 db_printf(" la_rt=%p la_hold=%p, la_asked=0x%lx\n", 1545 la->la_rt, la->la_hold, la->la_asked); 1546 } 1547 1548 /* 1549 * Function to pass to rt_walktree(). 1550 * Return non-zero error to abort walk. 1551 */ 1552 static int 1553 db_show_rtentry(struct rtentry *rt, void *w) 1554 { 1555 db_printf("rtentry=%p", rt); 1556 1557 db_printf(" flags=0x%x refcnt=%d use=%ld expire=%lld\n", 1558 rt->rt_flags, rt->rt_refcnt, 1559 rt->rt_use, (long long)rt->rt_expire); 1560 1561 db_printf(" key="); db_print_sa(rt_getkey(rt)); 1562 db_printf(" mask="); db_print_sa(rt_mask(rt)); 1563 db_printf(" gw="); db_print_sa(rt->rt_gateway); 1564 1565 db_printf(" ifp=%p ", rt->rt_ifp); 1566 if (rt->rt_ifp) 1567 db_printf("(%s)", rt->rt_ifp->if_xname); 1568 else 1569 db_printf("(NULL)"); 1570 1571 db_printf(" ifa=%p\n", rt->rt_ifa); 1572 db_print_ifa(rt->rt_ifa); 1573 1574 db_printf(" gwroute=%p llinfo=%p\n", 1575 rt->rt_gwroute, rt->rt_llinfo); 1576 db_print_llinfo(rt->rt_llinfo); 1577 1578 return 0; 1579 } 1580 1581 /* 1582 * Function to print all the route trees. 1583 * Use this from ddb: "show arptab" 1584 */ 1585 void 1586 db_show_arptab(db_expr_t addr, bool have_addr, 1587 db_expr_t count, const char *modif) 1588 { 1589 rt_walktree(AF_INET, db_show_rtentry, NULL); 1590 } 1591 #endif 1592 1593 static int 1594 sysctl_net_inet_arp_stats(SYSCTLFN_ARGS) 1595 { 1596 1597 return NETSTAT_SYSCTL(arpstat_percpu, ARP_NSTATS); 1598 } 1599 1600 static void 1601 sysctl_net_inet_arp_setup(struct sysctllog **clog) 1602 { 1603 const struct sysctlnode *node; 1604 1605 sysctl_createv(clog, 0, NULL, NULL, 1606 CTLFLAG_PERMANENT, 1607 CTLTYPE_NODE, "net", NULL, 1608 NULL, 0, NULL, 0, 1609 CTL_NET, CTL_EOL); 1610 sysctl_createv(clog, 0, NULL, NULL, 1611 CTLFLAG_PERMANENT, 1612 CTLTYPE_NODE, "inet", NULL, 1613 NULL, 0, NULL, 0, 1614 CTL_NET, PF_INET, CTL_EOL); 1615 sysctl_createv(clog, 0, NULL, &node, 1616 CTLFLAG_PERMANENT, 1617 CTLTYPE_NODE, "arp", 1618 SYSCTL_DESCR("Address Resolution Protocol"), 1619 NULL, 0, NULL, 0, 1620 CTL_NET, PF_INET, CTL_CREATE, CTL_EOL); 1621 1622 sysctl_createv(clog, 0, NULL, NULL, 1623 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1624 CTLTYPE_INT, "prune", 1625 SYSCTL_DESCR("ARP cache pruning interval"), 1626 NULL, 0, &arpt_prune, 0, 1627 CTL_NET,PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL); 1628 1629 sysctl_createv(clog, 0, NULL, NULL, 1630 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1631 CTLTYPE_INT, "keep", 1632 SYSCTL_DESCR("Valid ARP entry lifetime"), 1633 NULL, 0, &arpt_keep, 0, 1634 CTL_NET,PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL); 1635 1636 sysctl_createv(clog, 0, NULL, NULL, 1637 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1638 CTLTYPE_INT, "down", 1639 SYSCTL_DESCR("Failed ARP entry lifetime"), 1640 NULL, 0, &arpt_down, 0, 1641 CTL_NET,PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL); 1642 1643 sysctl_createv(clog, 0, NULL, NULL, 1644 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1645 CTLTYPE_INT, "refresh", 1646 SYSCTL_DESCR("ARP entry refresh interval"), 1647 NULL, 0, &arpt_refresh, 0, 1648 CTL_NET,PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL); 1649 1650 sysctl_createv(clog, 0, NULL, NULL, 1651 CTLFLAG_PERMANENT, 1652 CTLTYPE_STRUCT, "stats", 1653 SYSCTL_DESCR("ARP statistics"), 1654 sysctl_net_inet_arp_stats, 0, NULL, 0, 1655 CTL_NET,PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL); 1656 } 1657 1658 #endif /* INET */ 1659