1 /* $NetBSD: if_arp.c,v 1.149 2009/11/20 02:14:57 christos 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 1.149 2009/11/20 02:14:57 christos 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 /* 973 * Search for a matching interface address 974 * or any address on the interface to use 975 * as a dummy address in the rest of this function 976 */ 977 978 INADDR_TO_IA(itaddr, ia); 979 while (ia != NULL) { 980 #if NCARP > 0 981 if (ia->ia_ifp->if_type == IFT_CARP && 982 ((ia->ia_ifp->if_flags & (IFF_UP|IFF_RUNNING)) == 983 (IFF_UP|IFF_RUNNING))) { 984 index++; 985 if (ia->ia_ifp == m->m_pkthdr.rcvif && 986 carp_iamatch(ia, ar_sha(ah), 987 &count, index)) { 988 break; 989 } 990 } else 991 #endif 992 if (ia->ia_ifp == m->m_pkthdr.rcvif) 993 break; 994 #if NBRIDGE > 0 995 /* 996 * If the interface we received the packet on 997 * is part of a bridge, check to see if we need 998 * to "bridge" the packet to ourselves at this 999 * layer. Note we still prefer a perfect match, 1000 * but allow this weaker match if necessary. 1001 */ 1002 if (m->m_pkthdr.rcvif->if_bridge != NULL && 1003 m->m_pkthdr.rcvif->if_bridge == ia->ia_ifp->if_bridge) 1004 bridge_ia = ia; 1005 #endif /* NBRIDGE > 0 */ 1006 1007 NEXT_IA_WITH_SAME_ADDR(ia); 1008 } 1009 1010 #if NBRIDGE > 0 1011 if (ia == NULL && bridge_ia != NULL) { 1012 ia = bridge_ia; 1013 ifp = bridge_ia->ia_ifp; 1014 } 1015 #endif 1016 1017 if (ia == NULL) { 1018 INADDR_TO_IA(isaddr, ia); 1019 while ((ia != NULL) && ia->ia_ifp != m->m_pkthdr.rcvif) 1020 NEXT_IA_WITH_SAME_ADDR(ia); 1021 1022 if (ia == NULL) { 1023 IFP_TO_IA(ifp, ia); 1024 if (ia == NULL) { 1025 ARP_STATINC(ARP_STAT_RCVNOINT); 1026 goto out; 1027 } 1028 } 1029 } 1030 1031 myaddr = ia->ia_addr.sin_addr; 1032 1033 /* XXX checks for bridge case? */ 1034 if (!memcmp(ar_sha(ah), CLLADDR(ifp->if_sadl), ifp->if_addrlen)) { 1035 ARP_STATINC(ARP_STAT_RCVLOCALSHA); 1036 goto out; /* it's from me, ignore it. */ 1037 } 1038 1039 /* XXX checks for bridge case? */ 1040 if (!memcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) { 1041 ARP_STATINC(ARP_STAT_RCVBCASTSHA); 1042 log(LOG_ERR, 1043 "%s: arp: link address is broadcast for IP address %s!\n", 1044 ifp->if_xname, in_fmtaddr(isaddr)); 1045 goto out; 1046 } 1047 1048 /* 1049 * If the source IP address is zero, this is an RFC 5227 ARP probe 1050 */ 1051 if (in_nullhost(isaddr)) { 1052 ARP_STATINC(ARP_STAT_RCVZEROSPA); 1053 goto reply; 1054 } 1055 1056 if (in_hosteq(isaddr, myaddr)) { 1057 ARP_STATINC(ARP_STAT_RCVLOCALSPA); 1058 log(LOG_ERR, 1059 "duplicate IP address %s sent from link address %s\n", 1060 in_fmtaddr(isaddr), lla_snprintf(ar_sha(ah), ah->ar_hln)); 1061 itaddr = myaddr; 1062 goto reply; 1063 } 1064 la = arplookup(m, &isaddr, in_hosteq(itaddr, myaddr), 0); 1065 if (la != NULL && (rt = la->la_rt) && (sdl = satosdl(rt->rt_gateway))) { 1066 if (sdl->sdl_alen && 1067 memcmp(ar_sha(ah), CLLADDR(sdl), sdl->sdl_alen)) { 1068 if (rt->rt_flags & RTF_STATIC) { 1069 ARP_STATINC(ARP_STAT_RCVOVERPERM); 1070 log(LOG_INFO, 1071 "%s tried to overwrite permanent arp info" 1072 " for %s\n", 1073 lla_snprintf(ar_sha(ah), ah->ar_hln), 1074 in_fmtaddr(isaddr)); 1075 goto out; 1076 } else if (rt->rt_ifp != ifp) { 1077 ARP_STATINC(ARP_STAT_RCVOVERINT); 1078 log(LOG_INFO, 1079 "%s on %s tried to overwrite " 1080 "arp info for %s on %s\n", 1081 lla_snprintf(ar_sha(ah), ah->ar_hln), 1082 ifp->if_xname, in_fmtaddr(isaddr), 1083 rt->rt_ifp->if_xname); 1084 goto out; 1085 } else { 1086 ARP_STATINC(ARP_STAT_RCVOVER); 1087 log(LOG_INFO, 1088 "arp info overwritten for %s by %s\n", 1089 in_fmtaddr(isaddr), 1090 lla_snprintf(ar_sha(ah), ah->ar_hln)); 1091 } 1092 } 1093 /* 1094 * sanity check for the address length. 1095 * XXX this does not work for protocols with variable address 1096 * length. -is 1097 */ 1098 if (sdl->sdl_alen && 1099 sdl->sdl_alen != ah->ar_hln) { 1100 ARP_STATINC(ARP_STAT_RCVLENCHG); 1101 log(LOG_WARNING, 1102 "arp from %s: new addr len %d, was %d\n", 1103 in_fmtaddr(isaddr), ah->ar_hln, sdl->sdl_alen); 1104 } 1105 if (ifp->if_addrlen != ah->ar_hln) { 1106 ARP_STATINC(ARP_STAT_RCVBADLEN); 1107 log(LOG_WARNING, 1108 "arp from %s: addr len: new %d, i/f %d (ignored)\n", 1109 in_fmtaddr(isaddr), ah->ar_hln, 1110 ifp->if_addrlen); 1111 goto reply; 1112 } 1113 #if NTOKEN > 0 1114 /* 1115 * XXX uses m_data and assumes the complete answer including 1116 * XXX token-ring headers is in the same buf 1117 */ 1118 if (ifp->if_type == IFT_ISO88025) { 1119 struct token_header *trh; 1120 1121 trh = (struct token_header *)M_TRHSTART(m); 1122 if (trh->token_shost[0] & TOKEN_RI_PRESENT) { 1123 struct token_rif *rif; 1124 size_t riflen; 1125 1126 rif = TOKEN_RIF(trh); 1127 riflen = (ntohs(rif->tr_rcf) & 1128 TOKEN_RCF_LEN_MASK) >> 8; 1129 1130 if (riflen > 2 && 1131 riflen < sizeof(struct token_rif) && 1132 (riflen & 1) == 0) { 1133 rif->tr_rcf ^= htons(TOKEN_RCF_DIRECTION); 1134 rif->tr_rcf &= htons(~TOKEN_RCF_BROADCAST_MASK); 1135 memcpy(TOKEN_RIF(la), rif, riflen); 1136 } 1137 } 1138 } 1139 #endif /* NTOKEN > 0 */ 1140 (void)sockaddr_dl_setaddr(sdl, sdl->sdl_len, ar_sha(ah), 1141 ah->ar_hln); 1142 if (rt->rt_expire) 1143 rt->rt_expire = time_second + arpt_keep; 1144 rt->rt_flags &= ~RTF_REJECT; 1145 la->la_asked = 0; 1146 1147 s = splnet(); 1148 mold = la->la_hold; 1149 la->la_hold = 0; 1150 splx(s); 1151 1152 if (mold) { 1153 ARP_STATINC(ARP_STAT_DFRSENT); 1154 (*ifp->if_output)(ifp, mold, rt_getkey(rt), rt); 1155 } 1156 } 1157 reply: 1158 if (op != ARPOP_REQUEST) { 1159 if (op == ARPOP_REPLY) 1160 ARP_STATINC(ARP_STAT_RCVREPLY); 1161 out: 1162 m_freem(m); 1163 return; 1164 } 1165 ARP_STATINC(ARP_STAT_RCVREQUEST); 1166 if (in_hosteq(itaddr, myaddr)) { 1167 /* I am the target */ 1168 tha = ar_tha(ah); 1169 if (tha) 1170 memcpy(tha, ar_sha(ah), ah->ar_hln); 1171 memcpy(ar_sha(ah), CLLADDR(ifp->if_sadl), ah->ar_hln); 1172 } else { 1173 la = arplookup(m, &itaddr, 0, SIN_PROXY); 1174 if (la == NULL) 1175 goto out; 1176 rt = la->la_rt; 1177 if (rt->rt_ifp->if_type == IFT_CARP && 1178 m->m_pkthdr.rcvif->if_type != IFT_CARP) 1179 goto out; 1180 tha = ar_tha(ah); 1181 if (tha) 1182 memcpy(tha, ar_sha(ah), ah->ar_hln); 1183 sdl = satosdl(rt->rt_gateway); 1184 memcpy(ar_sha(ah), CLLADDR(sdl), ah->ar_hln); 1185 } 1186 1187 memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln); 1188 memcpy(ar_spa(ah), &itaddr, ah->ar_pln); 1189 ah->ar_op = htons(ARPOP_REPLY); 1190 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 1191 switch (ifp->if_type) { 1192 case IFT_IEEE1394: 1193 /* 1194 * ieee1394 arp reply is broadcast 1195 */ 1196 m->m_flags &= ~M_MCAST; 1197 m->m_flags |= M_BCAST; 1198 m->m_len = sizeof(*ah) + (2 * ah->ar_pln) + ah->ar_hln; 1199 break; 1200 1201 default: 1202 m->m_flags &= ~(M_BCAST|M_MCAST); /* never reply by broadcast */ 1203 m->m_len = sizeof(*ah) + (2 * ah->ar_pln) + (2 * ah->ar_hln); 1204 break; 1205 } 1206 m->m_pkthdr.len = m->m_len; 1207 sa.sa_family = AF_ARP; 1208 sa.sa_len = 2; 1209 arps = ARP_STAT_GETREF(); 1210 arps[ARP_STAT_SNDTOTAL]++; 1211 arps[ARP_STAT_SNDREPLY]++; 1212 ARP_STAT_PUTREF(); 1213 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 1214 return; 1215 } 1216 1217 /* 1218 * Free an arp entry. 1219 */ 1220 static void arptfree(struct llinfo_arp *la) 1221 { 1222 struct rtentry *rt = la->la_rt; 1223 struct sockaddr_dl *sdl; 1224 1225 ARP_LOCK_CHECK(); 1226 1227 if (rt == NULL) 1228 panic("arptfree"); 1229 if (rt->rt_refcnt > 0 && (sdl = satosdl(rt->rt_gateway)) && 1230 sdl->sdl_family == AF_LINK) { 1231 sdl->sdl_alen = 0; 1232 la->la_asked = 0; 1233 rt->rt_flags &= ~RTF_REJECT; 1234 return; 1235 } 1236 rtrequest(RTM_DELETE, rt_getkey(rt), NULL, rt_mask(rt), 0, NULL); 1237 } 1238 1239 static struct llinfo_arp * 1240 arplookup(struct mbuf *m, const struct in_addr *addr, int create, int proxy) 1241 { 1242 return arplookup1(m, addr, create, proxy, NULL); 1243 } 1244 1245 /* 1246 * Lookup or enter a new address in arptab. 1247 */ 1248 static struct llinfo_arp * 1249 arplookup1(struct mbuf *m, const struct in_addr *addr, int create, int proxy, 1250 struct rtentry *rt0) 1251 { 1252 struct arphdr *ah; 1253 struct ifnet *ifp = m->m_pkthdr.rcvif; 1254 struct rtentry *rt; 1255 struct sockaddr_inarp sin; 1256 const char *why = NULL; 1257 1258 ah = mtod(m, struct arphdr *); 1259 if (rt0 == NULL) { 1260 memset(&sin, 0, sizeof(sin)); 1261 sin.sin_len = sizeof(sin); 1262 sin.sin_family = AF_INET; 1263 sin.sin_addr = *addr; 1264 sin.sin_other = proxy ? SIN_PROXY : 0; 1265 rt = rtalloc1(sintosa(&sin), create); 1266 if (rt == NULL) 1267 return NULL; 1268 rt->rt_refcnt--; 1269 } else 1270 rt = rt0; 1271 1272 #define IS_LLINFO(__rt) \ 1273 (((__rt)->rt_flags & (RTF_GATEWAY | RTF_LLINFO)) == RTF_LLINFO && \ 1274 (__rt)->rt_gateway->sa_family == AF_LINK) 1275 1276 1277 if (IS_LLINFO(rt)) 1278 return (struct llinfo_arp *)rt->rt_llinfo; 1279 1280 if (create) { 1281 if (rt->rt_flags & RTF_GATEWAY) 1282 why = "host is not on local network"; 1283 else if ((rt->rt_flags & RTF_LLINFO) == 0) { 1284 ARP_STATINC(ARP_STAT_ALLOCFAIL); 1285 why = "could not allocate llinfo"; 1286 } else 1287 why = "gateway route is not ours"; 1288 log(LOG_DEBUG, "arplookup: unable to enter address" 1289 " for %s@%s on %s (%s)\n", 1290 in_fmtaddr(*addr), lla_snprintf(ar_sha(ah), ah->ar_hln), 1291 (ifp) ? ifp->if_xname : "null", why); 1292 if (rt->rt_refcnt <= 0 && (rt->rt_flags & RTF_CLONED) != 0) { 1293 rtrequest(RTM_DELETE, rt_getkey(rt), 1294 rt->rt_gateway, rt_mask(rt), rt->rt_flags, NULL); 1295 } 1296 } 1297 return NULL; 1298 } 1299 1300 int 1301 arpioctl(u_long cmd, void *data) 1302 { 1303 1304 return EOPNOTSUPP; 1305 } 1306 1307 void 1308 arp_ifinit(struct ifnet *ifp, struct ifaddr *ifa) 1309 { 1310 struct in_addr *ip; 1311 1312 /* 1313 * Warn the user if another station has this IP address, 1314 * but only if the interface IP address is not zero. 1315 */ 1316 ip = &IA_SIN(ifa)->sin_addr; 1317 if (!in_nullhost(*ip)) 1318 arprequest(ifp, ip, ip, CLLADDR(ifp->if_sadl)); 1319 1320 ifa->ifa_rtrequest = arp_rtrequest; 1321 ifa->ifa_flags |= RTF_CLONING; 1322 } 1323 1324 /* 1325 * Called from 10 Mb/s Ethernet interrupt handlers 1326 * when ether packet type ETHERTYPE_REVARP 1327 * is received. Common length and type checks are done here, 1328 * then the protocol-specific routine is called. 1329 */ 1330 void 1331 revarpinput(struct mbuf *m) 1332 { 1333 struct arphdr *ar; 1334 1335 if (m->m_len < sizeof(struct arphdr)) 1336 goto out; 1337 ar = mtod(m, struct arphdr *); 1338 #if 0 /* XXX I don't think we need this... and it will prevent other LL */ 1339 if (ntohs(ar->ar_hrd) != ARPHRD_ETHER) 1340 goto out; 1341 #endif 1342 if (m->m_len < sizeof(struct arphdr) + 2 * (ar->ar_hln + ar->ar_pln)) 1343 goto out; 1344 switch (ntohs(ar->ar_pro)) { 1345 case ETHERTYPE_IP: 1346 case ETHERTYPE_IPTRAILERS: 1347 in_revarpinput(m); 1348 return; 1349 1350 default: 1351 break; 1352 } 1353 out: 1354 m_freem(m); 1355 } 1356 1357 /* 1358 * RARP for Internet protocols on 10 Mb/s Ethernet. 1359 * Algorithm is that given in RFC 903. 1360 * We are only using for bootstrap purposes to get an ip address for one of 1361 * our interfaces. Thus we support no user-interface. 1362 * 1363 * Since the contents of the RARP reply are specific to the interface that 1364 * sent the request, this code must ensure that they are properly associated. 1365 * 1366 * Note: also supports ARP via RARP packets, per the RFC. 1367 */ 1368 void 1369 in_revarpinput(struct mbuf *m) 1370 { 1371 struct ifnet *ifp; 1372 struct arphdr *ah; 1373 void *tha; 1374 int op; 1375 1376 ah = mtod(m, struct arphdr *); 1377 op = ntohs(ah->ar_op); 1378 1379 switch (m->m_pkthdr.rcvif->if_type) { 1380 case IFT_IEEE1394: 1381 /* ARP without target hardware address is not supported */ 1382 goto out; 1383 default: 1384 break; 1385 } 1386 1387 switch (op) { 1388 case ARPOP_REQUEST: 1389 case ARPOP_REPLY: /* per RFC */ 1390 in_arpinput(m); 1391 return; 1392 case ARPOP_REVREPLY: 1393 break; 1394 case ARPOP_REVREQUEST: /* handled by rarpd(8) */ 1395 default: 1396 goto out; 1397 } 1398 if (!revarp_in_progress) 1399 goto out; 1400 ifp = m->m_pkthdr.rcvif; 1401 if (ifp != myip_ifp) /* !same interface */ 1402 goto out; 1403 if (myip_initialized) 1404 goto wake; 1405 tha = ar_tha(ah); 1406 if (tha == NULL) 1407 goto out; 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 if (tha == NULL) 1449 return; 1450 memcpy(tha, CLLADDR(ifp->if_sadl), ah->ar_hln); 1451 1452 sa.sa_family = AF_ARP; 1453 sa.sa_len = 2; 1454 m->m_flags |= M_BCAST; 1455 (*ifp->if_output)(ifp, m, &sa, NULL); 1456 1457 } 1458 1459 /* 1460 * RARP for the ip address of the specified interface, but also 1461 * save the ip address of the server that sent the answer. 1462 * Timeout if no response is received. 1463 */ 1464 int 1465 revarpwhoarewe(struct ifnet *ifp, struct in_addr *serv_in, 1466 struct in_addr *clnt_in) 1467 { 1468 int result, count = 20; 1469 1470 myip_initialized = 0; 1471 myip_ifp = ifp; 1472 1473 revarp_in_progress = 1; 1474 while (count--) { 1475 revarprequest(ifp); 1476 result = tsleep((void *)&myip, PSOCK, "revarp", hz/2); 1477 if (result != EWOULDBLOCK) 1478 break; 1479 } 1480 revarp_in_progress = 0; 1481 1482 if (!myip_initialized) 1483 return ENETUNREACH; 1484 1485 memcpy(serv_in, &srv_ip, sizeof(*serv_in)); 1486 memcpy(clnt_in, &myip, sizeof(*clnt_in)); 1487 return 0; 1488 } 1489 1490 1491 1492 #ifdef DDB 1493 1494 #include <machine/db_machdep.h> 1495 #include <ddb/db_interface.h> 1496 #include <ddb/db_output.h> 1497 1498 static void 1499 db_print_sa(const struct sockaddr *sa) 1500 { 1501 int len; 1502 const u_char *p; 1503 1504 if (sa == NULL) { 1505 db_printf("[NULL]"); 1506 return; 1507 } 1508 1509 p = (const u_char *)sa; 1510 len = sa->sa_len; 1511 db_printf("["); 1512 while (len > 0) { 1513 db_printf("%d", *p); 1514 p++; len--; 1515 if (len) db_printf(","); 1516 } 1517 db_printf("]\n"); 1518 } 1519 1520 static void 1521 db_print_ifa(struct ifaddr *ifa) 1522 { 1523 if (ifa == NULL) 1524 return; 1525 db_printf(" ifa_addr="); 1526 db_print_sa(ifa->ifa_addr); 1527 db_printf(" ifa_dsta="); 1528 db_print_sa(ifa->ifa_dstaddr); 1529 db_printf(" ifa_mask="); 1530 db_print_sa(ifa->ifa_netmask); 1531 db_printf(" flags=0x%x,refcnt=%d,metric=%d\n", 1532 ifa->ifa_flags, 1533 ifa->ifa_refcnt, 1534 ifa->ifa_metric); 1535 } 1536 1537 static void 1538 db_print_llinfo(void *li) 1539 { 1540 struct llinfo_arp *la; 1541 1542 if (li == NULL) 1543 return; 1544 la = (struct llinfo_arp *)li; 1545 db_printf(" la_rt=%p la_hold=%p, la_asked=0x%lx\n", 1546 la->la_rt, la->la_hold, la->la_asked); 1547 } 1548 1549 /* 1550 * Function to pass to rt_walktree(). 1551 * Return non-zero error to abort walk. 1552 */ 1553 static int 1554 db_show_rtentry(struct rtentry *rt, void *w) 1555 { 1556 db_printf("rtentry=%p", rt); 1557 1558 db_printf(" flags=0x%x refcnt=%d use=%ld expire=%lld\n", 1559 rt->rt_flags, rt->rt_refcnt, 1560 rt->rt_use, (long long)rt->rt_expire); 1561 1562 db_printf(" key="); db_print_sa(rt_getkey(rt)); 1563 db_printf(" mask="); db_print_sa(rt_mask(rt)); 1564 db_printf(" gw="); db_print_sa(rt->rt_gateway); 1565 1566 db_printf(" ifp=%p ", rt->rt_ifp); 1567 if (rt->rt_ifp) 1568 db_printf("(%s)", rt->rt_ifp->if_xname); 1569 else 1570 db_printf("(NULL)"); 1571 1572 db_printf(" ifa=%p\n", rt->rt_ifa); 1573 db_print_ifa(rt->rt_ifa); 1574 1575 db_printf(" gwroute=%p llinfo=%p\n", 1576 rt->rt_gwroute, rt->rt_llinfo); 1577 db_print_llinfo(rt->rt_llinfo); 1578 1579 return 0; 1580 } 1581 1582 /* 1583 * Function to print all the route trees. 1584 * Use this from ddb: "show arptab" 1585 */ 1586 void 1587 db_show_arptab(db_expr_t addr, bool have_addr, 1588 db_expr_t count, const char *modif) 1589 { 1590 rt_walktree(AF_INET, db_show_rtentry, NULL); 1591 } 1592 #endif 1593 1594 static int 1595 sysctl_net_inet_arp_stats(SYSCTLFN_ARGS) 1596 { 1597 1598 return NETSTAT_SYSCTL(arpstat_percpu, ARP_NSTATS); 1599 } 1600 1601 static void 1602 sysctl_net_inet_arp_setup(struct sysctllog **clog) 1603 { 1604 const struct sysctlnode *node; 1605 1606 sysctl_createv(clog, 0, NULL, NULL, 1607 CTLFLAG_PERMANENT, 1608 CTLTYPE_NODE, "net", NULL, 1609 NULL, 0, NULL, 0, 1610 CTL_NET, CTL_EOL); 1611 sysctl_createv(clog, 0, NULL, NULL, 1612 CTLFLAG_PERMANENT, 1613 CTLTYPE_NODE, "inet", NULL, 1614 NULL, 0, NULL, 0, 1615 CTL_NET, PF_INET, CTL_EOL); 1616 sysctl_createv(clog, 0, NULL, &node, 1617 CTLFLAG_PERMANENT, 1618 CTLTYPE_NODE, "arp", 1619 SYSCTL_DESCR("Address Resolution Protocol"), 1620 NULL, 0, NULL, 0, 1621 CTL_NET, PF_INET, CTL_CREATE, CTL_EOL); 1622 1623 sysctl_createv(clog, 0, NULL, NULL, 1624 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1625 CTLTYPE_INT, "prune", 1626 SYSCTL_DESCR("ARP cache pruning interval"), 1627 NULL, 0, &arpt_prune, 0, 1628 CTL_NET,PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL); 1629 1630 sysctl_createv(clog, 0, NULL, NULL, 1631 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1632 CTLTYPE_INT, "keep", 1633 SYSCTL_DESCR("Valid ARP entry lifetime"), 1634 NULL, 0, &arpt_keep, 0, 1635 CTL_NET,PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL); 1636 1637 sysctl_createv(clog, 0, NULL, NULL, 1638 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1639 CTLTYPE_INT, "down", 1640 SYSCTL_DESCR("Failed ARP entry lifetime"), 1641 NULL, 0, &arpt_down, 0, 1642 CTL_NET,PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL); 1643 1644 sysctl_createv(clog, 0, NULL, NULL, 1645 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1646 CTLTYPE_INT, "refresh", 1647 SYSCTL_DESCR("ARP entry refresh interval"), 1648 NULL, 0, &arpt_refresh, 0, 1649 CTL_NET,PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL); 1650 1651 sysctl_createv(clog, 0, NULL, NULL, 1652 CTLFLAG_PERMANENT, 1653 CTLTYPE_STRUCT, "stats", 1654 SYSCTL_DESCR("ARP statistics"), 1655 sysctl_net_inet_arp_stats, 0, NULL, 0, 1656 CTL_NET,PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL); 1657 } 1658 1659 #endif /* INET */ 1660