1 /* $NetBSD: if_arp.c,v 1.140 2008/05/13 18:24:01 dyoung 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 1.140 2008/05/13 18:24:01 dyoung 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 void 322 arp_init(void) 323 { 324 325 arpstat_percpu = percpu_alloc(sizeof(uint64_t) * ARP_NSTATS); 326 } 327 328 /* 329 * ARP protocol drain routine. Called when memory is in short supply. 330 * Called at splvm(); don't acquire softnet_lock as can be called from 331 * hardware interrupt handlers. 332 */ 333 void 334 arp_drain(void) 335 { 336 struct llinfo_arp *la, *nla; 337 int count = 0; 338 struct mbuf *mold; 339 340 KERNEL_LOCK(1, NULL); 341 342 if (arp_lock_try(0) == 0) { 343 printf("arp_drain: locked; punting\n"); 344 KERNEL_UNLOCK_ONE(NULL); 345 return; 346 } 347 348 for (la = LIST_FIRST(&llinfo_arp); la != NULL; la = nla) { 349 nla = LIST_NEXT(la, la_list); 350 351 mold = la->la_hold; 352 la->la_hold = 0; 353 354 if (mold) { 355 m_freem(mold); 356 count++; 357 } 358 } 359 ARP_UNLOCK(); 360 ARP_STATADD(ARP_STAT_DFRDROPPED, count); 361 KERNEL_UNLOCK_ONE(NULL); 362 } 363 364 365 /* 366 * Timeout routine. Age arp_tab entries periodically. 367 */ 368 /* ARGSUSED */ 369 static void 370 arptimer(void *arg) 371 { 372 struct llinfo_arp *la, *nla; 373 374 mutex_enter(softnet_lock); 375 KERNEL_LOCK(1, NULL); 376 377 if (arp_lock_try(0) == 0) { 378 /* get it later.. */ 379 KERNEL_UNLOCK_ONE(NULL); 380 mutex_exit(softnet_lock); 381 return; 382 } 383 384 callout_reset(&arptimer_ch, arpt_prune * hz, arptimer, NULL); 385 for (la = LIST_FIRST(&llinfo_arp); la != NULL; la = nla) { 386 struct rtentry *rt = la->la_rt; 387 388 nla = LIST_NEXT(la, la_list); 389 if (rt->rt_expire == 0) 390 continue; 391 if ((rt->rt_expire - time_second) < arpt_refresh && 392 rt->rt_pksent > (time_second - arpt_keep)) { 393 /* 394 * If the entry has been used during since last 395 * refresh, try to renew it before deleting. 396 */ 397 arprequest(rt->rt_ifp, 398 &satocsin(rt->rt_ifa->ifa_addr)->sin_addr, 399 &satocsin(rt_getkey(rt))->sin_addr, 400 CLLADDR(rt->rt_ifp->if_sadl)); 401 } else if (rt->rt_expire <= time_second) 402 arptfree(la); /* timer has expired; clear */ 403 } 404 405 ARP_UNLOCK(); 406 407 KERNEL_UNLOCK_ONE(NULL); 408 mutex_exit(softnet_lock); 409 } 410 411 /* 412 * We set the gateway for RTF_CLONING routes to a "prototype" 413 * link-layer sockaddr whose interface type (if_type) and interface 414 * index (if_index) fields are prepared. 415 */ 416 static struct sockaddr * 417 arp_setgate(struct rtentry *rt, struct sockaddr *gate, 418 const struct sockaddr *netmask) 419 { 420 const struct ifnet *ifp = rt->rt_ifp; 421 uint8_t namelen = strlen(ifp->if_xname); 422 uint8_t addrlen = ifp->if_addrlen; 423 424 /* 425 * XXX: If this is a manually added route to interface 426 * such as older version of routed or gated might provide, 427 * restore cloning bit. 428 */ 429 if ((rt->rt_flags & RTF_HOST) == 0 && netmask != NULL && 430 satocsin(netmask)->sin_addr.s_addr != 0xffffffff) 431 rt->rt_flags |= RTF_CLONING; 432 if (rt->rt_flags & RTF_CLONING) { 433 union { 434 struct sockaddr sa; 435 struct sockaddr_storage ss; 436 struct sockaddr_dl sdl; 437 } u; 438 /* 439 * Case 1: This route should come from a route to iface. 440 */ 441 sockaddr_dl_init(&u.sdl, sizeof(u.ss), 442 ifp->if_index, ifp->if_type, NULL, namelen, NULL, addrlen); 443 rt_setgate(rt, &u.sa); 444 gate = rt->rt_gateway; 445 } 446 return gate; 447 } 448 449 /* 450 * Parallel to llc_rtrequest. 451 */ 452 void 453 arp_rtrequest(int req, struct rtentry *rt, struct rt_addrinfo *info) 454 { 455 struct sockaddr *gate = rt->rt_gateway; 456 struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo; 457 size_t allocsize; 458 struct mbuf *mold; 459 int s; 460 struct in_ifaddr *ia; 461 struct ifaddr *ifa; 462 struct ifnet *ifp = rt->rt_ifp; 463 uint8_t namelen = strlen(ifp->if_xname); 464 uint8_t addrlen = ifp->if_addrlen; 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 ((rt->rt_flags & RTF_GATEWAY) != 0) { 483 if (req != RTM_ADD) 484 return; 485 486 /* 487 * linklayers with particular link MTU limitation. 488 */ 489 switch(ifp->if_type) { 490 #if NFDDI > 0 491 case IFT_FDDI: 492 if (ifp->if_mtu > FDDIIPMTU) 493 rt->rt_rmx.rmx_mtu = FDDIIPMTU; 494 break; 495 #endif 496 #if NARC > 0 497 case IFT_ARCNET: 498 { 499 int arcipifmtu; 500 501 if (ifp->if_flags & IFF_LINK0) 502 arcipifmtu = arc_ipmtu; 503 else 504 arcipifmtu = ARCMTU; 505 if (ifp->if_mtu > arcipifmtu) 506 rt->rt_rmx.rmx_mtu = arcipifmtu; 507 break; 508 } 509 #endif 510 } 511 return; 512 } 513 514 ARP_LOCK(1); /* we may already be locked here. */ 515 516 switch (req) { 517 518 case RTM_SETGATE: 519 gate = arp_setgate(rt, gate, info->rti_info[RTAX_NETMASK]); 520 break; 521 case RTM_ADD: 522 gate = arp_setgate(rt, gate, info->rti_info[RTAX_NETMASK]); 523 if (rt->rt_flags & RTF_CLONING) { 524 /* 525 * Give this route an expiration time, even though 526 * it's a "permanent" route, so that routes cloned 527 * from it do not need their expiration time set. 528 */ 529 rt->rt_expire = time_second; 530 /* 531 * linklayers with particular link MTU limitation. 532 */ 533 switch (ifp->if_type) { 534 #if NFDDI > 0 535 case IFT_FDDI: 536 if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0 && 537 (rt->rt_rmx.rmx_mtu > FDDIIPMTU || 538 (rt->rt_rmx.rmx_mtu == 0 && 539 ifp->if_mtu > FDDIIPMTU))) 540 rt->rt_rmx.rmx_mtu = FDDIIPMTU; 541 break; 542 #endif 543 #if NARC > 0 544 case IFT_ARCNET: 545 { 546 int arcipifmtu; 547 if (ifp->if_flags & IFF_LINK0) 548 arcipifmtu = arc_ipmtu; 549 else 550 arcipifmtu = ARCMTU; 551 552 if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0 && 553 (rt->rt_rmx.rmx_mtu > arcipifmtu || 554 (rt->rt_rmx.rmx_mtu == 0 && 555 ifp->if_mtu > arcipifmtu))) 556 rt->rt_rmx.rmx_mtu = arcipifmtu; 557 break; 558 } 559 #endif 560 } 561 break; 562 } 563 /* Announce a new entry if requested. */ 564 if (rt->rt_flags & RTF_ANNOUNCE) 565 arprequest(ifp, 566 &satocsin(rt_getkey(rt))->sin_addr, 567 &satocsin(rt_getkey(rt))->sin_addr, 568 CLLADDR(satocsdl(gate))); 569 /*FALLTHROUGH*/ 570 case RTM_RESOLVE: 571 if (gate->sa_family != AF_LINK || 572 gate->sa_len < sockaddr_dl_measure(namelen, addrlen)) { 573 log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n"); 574 break; 575 } 576 satosdl(gate)->sdl_type = ifp->if_type; 577 satosdl(gate)->sdl_index = ifp->if_index; 578 if (la != NULL) 579 break; /* This happens on a route change */ 580 /* 581 * Case 2: This route may come from cloning, or a manual route 582 * add with a LL address. 583 */ 584 switch (satocsdl(gate)->sdl_type) { 585 #if NTOKEN > 0 586 case IFT_ISO88025: 587 allocsize = sizeof(*la) + sizeof(struct token_rif); 588 break; 589 #endif /* NTOKEN > 0 */ 590 default: 591 allocsize = sizeof(*la); 592 } 593 R_Malloc(la, struct llinfo_arp *, allocsize); 594 rt->rt_llinfo = (void *)la; 595 if (la == NULL) { 596 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); 597 break; 598 } 599 arp_inuse++, arp_allocated++; 600 memset(la, 0, allocsize); 601 la->la_rt = rt; 602 rt->rt_flags |= RTF_LLINFO; 603 LIST_INSERT_HEAD(&llinfo_arp, la, la_list); 604 605 INADDR_TO_IA(satocsin(rt_getkey(rt))->sin_addr, ia); 606 while (ia && ia->ia_ifp != ifp) 607 NEXT_IA_WITH_SAME_ADDR(ia); 608 if (ia) { 609 /* 610 * This test used to be 611 * if (lo0ifp->if_flags & IFF_UP) 612 * It allowed local traffic to be forced through 613 * the hardware by configuring the loopback down. 614 * However, it causes problems during network 615 * configuration for boards that can't receive 616 * packets they send. It is now necessary to clear 617 * "useloopback" and remove the route to force 618 * traffic out to the hardware. 619 * 620 * In 4.4BSD, the above "if" statement checked 621 * rt->rt_ifa against rt_getkey(rt). It was changed 622 * to the current form so that we can provide a 623 * better support for multiple IPv4 addresses on a 624 * interface. 625 */ 626 rt->rt_expire = 0; 627 (void)sockaddr_dl_setaddr(satosdl(gate), gate->sa_len, 628 CLLADDR(ifp->if_sadl), ifp->if_addrlen); 629 if (useloopback) 630 ifp = rt->rt_ifp = lo0ifp; 631 /* 632 * make sure to set rt->rt_ifa to the interface 633 * address we are using, otherwise we will have trouble 634 * with source address selection. 635 */ 636 ifa = &ia->ia_ifa; 637 if (ifa != rt->rt_ifa) 638 rt_replace_ifa(rt, ifa); 639 } 640 break; 641 642 case RTM_DELETE: 643 if (la == NULL) 644 break; 645 arp_inuse--; 646 LIST_REMOVE(la, la_list); 647 rt->rt_llinfo = NULL; 648 rt->rt_flags &= ~RTF_LLINFO; 649 650 s = splnet(); 651 mold = la->la_hold; 652 la->la_hold = 0; 653 splx(s); 654 655 if (mold) 656 m_freem(mold); 657 658 Free((void *)la); 659 } 660 ARP_UNLOCK(); 661 } 662 663 /* 664 * Broadcast an ARP request. Caller specifies: 665 * - arp header source ip address 666 * - arp header target ip address 667 * - arp header source ethernet address 668 */ 669 void 670 arprequest(struct ifnet *ifp, 671 const struct in_addr *sip, const struct in_addr *tip, 672 const u_int8_t *enaddr) 673 { 674 struct mbuf *m; 675 struct arphdr *ah; 676 struct sockaddr sa; 677 uint64_t *arps; 678 679 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 680 return; 681 MCLAIM(m, &arpdomain.dom_mowner); 682 switch (ifp->if_type) { 683 case IFT_IEEE1394: 684 m->m_len = sizeof(*ah) + 2 * sizeof(struct in_addr) + 685 ifp->if_addrlen; 686 break; 687 default: 688 m->m_len = sizeof(*ah) + 2 * sizeof(struct in_addr) + 689 2 * ifp->if_addrlen; 690 break; 691 } 692 m->m_pkthdr.len = m->m_len; 693 MH_ALIGN(m, m->m_len); 694 ah = mtod(m, struct arphdr *); 695 memset(ah, 0, m->m_len); 696 switch (ifp->if_type) { 697 case IFT_IEEE1394: /* RFC2734 */ 698 /* fill it now for ar_tpa computation */ 699 ah->ar_hrd = htons(ARPHRD_IEEE1394); 700 break; 701 default: 702 /* ifp->if_output will fill ar_hrd */ 703 break; 704 } 705 ah->ar_pro = htons(ETHERTYPE_IP); 706 ah->ar_hln = ifp->if_addrlen; /* hardware address length */ 707 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 708 ah->ar_op = htons(ARPOP_REQUEST); 709 memcpy(ar_sha(ah), enaddr, ah->ar_hln); 710 memcpy(ar_spa(ah), sip, ah->ar_pln); 711 memcpy(ar_tpa(ah), tip, ah->ar_pln); 712 sa.sa_family = AF_ARP; 713 sa.sa_len = 2; 714 m->m_flags |= M_BCAST; 715 arps = ARP_STAT_GETREF(); 716 arps[ARP_STAT_SNDTOTAL]++; 717 arps[ARP_STAT_SENDREQUEST]++; 718 ARP_STAT_PUTREF(); 719 (*ifp->if_output)(ifp, m, &sa, NULL); 720 } 721 722 /* 723 * Resolve an IP address into an ethernet address. If success, 724 * desten is filled in. If there is no entry in arptab, 725 * set one up and broadcast a request for the IP address. 726 * Hold onto this mbuf and resend it once the address 727 * is finally resolved. A return value of 1 indicates 728 * that desten has been filled in and the packet should be sent 729 * normally; a 0 return indicates that the packet has been 730 * taken over here, either now or for later transmission. 731 */ 732 int 733 arpresolve(struct ifnet *ifp, struct rtentry *rt, struct mbuf *m, 734 const struct sockaddr *dst, u_char *desten) 735 { 736 struct llinfo_arp *la; 737 const struct sockaddr_dl *sdl; 738 struct mbuf *mold; 739 int s; 740 741 if ((la = arplookup1(m, &satocsin(dst)->sin_addr, 1, 0, rt)) != NULL) 742 rt = la->la_rt; 743 744 if (la == NULL || rt == NULL) { 745 ARP_STATINC(ARP_STAT_ALLOCFAIL); 746 log(LOG_DEBUG, 747 "arpresolve: can't allocate llinfo on %s for %s\n", 748 ifp->if_xname, in_fmtaddr(satocsin(dst)->sin_addr)); 749 m_freem(m); 750 return 0; 751 } 752 sdl = satocsdl(rt->rt_gateway); 753 /* 754 * Check the address family and length is valid, the address 755 * is resolved; otherwise, try to resolve. 756 */ 757 if ((rt->rt_expire == 0 || rt->rt_expire > time_second) && 758 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 759 memcpy(desten, CLLADDR(sdl), 760 min(sdl->sdl_alen, ifp->if_addrlen)); 761 rt->rt_pksent = time_second; /* Time for last pkt sent */ 762 return 1; 763 } 764 /* 765 * There is an arptab entry, but no ethernet address 766 * response yet. Replace the held mbuf with this 767 * latest one. 768 */ 769 770 ARP_STATINC(ARP_STAT_DFRTOTAL); 771 s = splnet(); 772 mold = la->la_hold; 773 la->la_hold = m; 774 splx(s); 775 776 if (mold) { 777 ARP_STATINC(ARP_STAT_DFRDROPPED); 778 m_freem(mold); 779 } 780 781 /* 782 * Re-send the ARP request when appropriate. 783 */ 784 #ifdef DIAGNOSTIC 785 if (rt->rt_expire == 0) { 786 /* This should never happen. (Should it? -gwr) */ 787 printf("arpresolve: unresolved and rt_expire == 0\n"); 788 /* Set expiration time to now (expired). */ 789 rt->rt_expire = time_second; 790 } 791 #endif 792 if (rt->rt_expire) { 793 rt->rt_flags &= ~RTF_REJECT; 794 if (la->la_asked == 0 || rt->rt_expire != time_second) { 795 rt->rt_expire = time_second; 796 if (la->la_asked++ < arp_maxtries) 797 arprequest(ifp, 798 &satocsin(rt->rt_ifa->ifa_addr)->sin_addr, 799 &satocsin(dst)->sin_addr, 800 #if NCARP > 0 801 (rt->rt_ifp->if_type == IFT_CARP) ? 802 CLLADDR(rt->rt_ifp->if_sadl): 803 #endif 804 CLLADDR(ifp->if_sadl)); 805 else { 806 rt->rt_flags |= RTF_REJECT; 807 rt->rt_expire += arpt_down; 808 la->la_asked = 0; 809 } 810 } 811 } 812 return 0; 813 } 814 815 /* 816 * Common length and type checks are done here, 817 * then the protocol-specific routine is called. 818 */ 819 void 820 arpintr(void) 821 { 822 struct mbuf *m; 823 struct arphdr *ar; 824 int s; 825 int arplen; 826 827 mutex_enter(softnet_lock); 828 KERNEL_LOCK(1, NULL); 829 while (arpintrq.ifq_head) { 830 s = splnet(); 831 IF_DEQUEUE(&arpintrq, m); 832 splx(s); 833 if (m == 0 || (m->m_flags & M_PKTHDR) == 0) 834 panic("arpintr"); 835 836 MCLAIM(m, &arpdomain.dom_mowner); 837 ARP_STATINC(ARP_STAT_RCVTOTAL); 838 839 /* 840 * First, make sure we have at least struct arphdr. 841 */ 842 if (m->m_len < sizeof(struct arphdr) || 843 (ar = mtod(m, struct arphdr *)) == NULL) 844 goto badlen; 845 846 switch (m->m_pkthdr.rcvif->if_type) { 847 case IFT_IEEE1394: 848 arplen = sizeof(struct arphdr) + 849 ar->ar_hln + 2 * ar->ar_pln; 850 break; 851 default: 852 arplen = sizeof(struct arphdr) + 853 2 * ar->ar_hln + 2 * ar->ar_pln; 854 break; 855 } 856 857 if (/* XXX ntohs(ar->ar_hrd) == ARPHRD_ETHER && */ 858 m->m_len >= arplen) 859 switch (ntohs(ar->ar_pro)) { 860 case ETHERTYPE_IP: 861 case ETHERTYPE_IPTRAILERS: 862 in_arpinput(m); 863 continue; 864 default: 865 ARP_STATINC(ARP_STAT_RCVBADPROTO); 866 } 867 else { 868 badlen: 869 ARP_STATINC(ARP_STAT_RCVBADLEN); 870 } 871 m_freem(m); 872 } 873 KERNEL_UNLOCK_ONE(NULL); 874 mutex_exit(softnet_lock); 875 } 876 877 /* 878 * ARP for Internet protocols on 10 Mb/s Ethernet. 879 * Algorithm is that given in RFC 826. 880 * In addition, a sanity check is performed on the sender 881 * protocol address, to catch impersonators. 882 * We no longer handle negotiations for use of trailer protocol: 883 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 884 * along with IP replies if we wanted trailers sent to us, 885 * and also sent them in response to IP replies. 886 * This allowed either end to announce the desire to receive 887 * trailer packets. 888 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 889 * but formerly didn't normally send requests. 890 */ 891 static void 892 in_arpinput(struct mbuf *m) 893 { 894 struct arphdr *ah; 895 struct ifnet *ifp = m->m_pkthdr.rcvif; 896 struct llinfo_arp *la = NULL; 897 struct rtentry *rt; 898 struct in_ifaddr *ia; 899 #if NBRIDGE > 0 900 struct in_ifaddr *bridge_ia = NULL; 901 #endif 902 #if NCARP > 0 903 u_int32_t count = 0, index = 0; 904 #endif 905 struct sockaddr_dl *sdl; 906 struct sockaddr sa; 907 struct in_addr isaddr, itaddr, myaddr; 908 int op; 909 struct mbuf *mold; 910 void *tha; 911 int s; 912 uint64_t *arps; 913 914 if (__predict_false(m_makewritable(&m, 0, m->m_pkthdr.len, M_DONTWAIT))) 915 goto out; 916 ah = mtod(m, struct arphdr *); 917 op = ntohs(ah->ar_op); 918 919 /* 920 * Fix up ah->ar_hrd if necessary, before using ar_tha() or 921 * ar_tpa(). 922 */ 923 switch (ifp->if_type) { 924 case IFT_IEEE1394: 925 if (ntohs(ah->ar_hrd) == ARPHRD_IEEE1394) 926 ; 927 else { 928 /* XXX this is to make sure we compute ar_tha right */ 929 /* XXX check ar_hrd more strictly? */ 930 ah->ar_hrd = htons(ARPHRD_IEEE1394); 931 } 932 break; 933 default: 934 /* XXX check ar_hrd? */ 935 break; 936 } 937 938 memcpy(&isaddr, ar_spa(ah), sizeof (isaddr)); 939 memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr)); 940 941 if (m->m_flags & (M_BCAST|M_MCAST)) 942 ARP_STATINC(ARP_STAT_RCVMCAST); 943 944 /* 945 * If the target IP address is zero, ignore the packet. 946 * This prevents the code below from tring to answer 947 * when we are using IP address zero (booting). 948 */ 949 if (in_nullhost(itaddr)) { 950 ARP_STATINC(ARP_STAT_RCVZEROTPA); 951 goto out; 952 } 953 954 /* 955 * If the source IP address is zero, this is most likely a 956 * confused host trying to use IP address zero. (Windoze?) 957 * XXX: Should we bother trying to reply to these? 958 */ 959 if (in_nullhost(isaddr)) { 960 ARP_STATINC(ARP_STAT_RCVZEROSPA); 961 goto out; 962 } 963 964 /* 965 * Search for a matching interface address 966 * or any address on the interface to use 967 * as a dummy address in the rest of this function 968 */ 969 970 INADDR_TO_IA(itaddr, ia); 971 while (ia != NULL) { 972 #if NCARP > 0 973 if (ia->ia_ifp->if_type == IFT_CARP && 974 ((ia->ia_ifp->if_flags & (IFF_UP|IFF_RUNNING)) == 975 (IFF_UP|IFF_RUNNING))) { 976 index++; 977 if (ia->ia_ifp == m->m_pkthdr.rcvif && 978 carp_iamatch(ia, ar_sha(ah), 979 &count, index)) { 980 break; 981 } 982 } else 983 #endif 984 if (ia->ia_ifp == m->m_pkthdr.rcvif) 985 break; 986 #if NBRIDGE > 0 987 /* 988 * If the interface we received the packet on 989 * is part of a bridge, check to see if we need 990 * to "bridge" the packet to ourselves at this 991 * layer. Note we still prefer a perfect match, 992 * but allow this weaker match if necessary. 993 */ 994 if (m->m_pkthdr.rcvif->if_bridge != NULL && 995 m->m_pkthdr.rcvif->if_bridge == ia->ia_ifp->if_bridge) 996 bridge_ia = ia; 997 #endif /* NBRIDGE > 0 */ 998 999 NEXT_IA_WITH_SAME_ADDR(ia); 1000 } 1001 1002 #if NBRIDGE > 0 1003 if (ia == NULL && bridge_ia != NULL) { 1004 ia = bridge_ia; 1005 ifp = bridge_ia->ia_ifp; 1006 } 1007 #endif 1008 1009 if (ia == NULL) { 1010 INADDR_TO_IA(isaddr, ia); 1011 while ((ia != NULL) && ia->ia_ifp != m->m_pkthdr.rcvif) 1012 NEXT_IA_WITH_SAME_ADDR(ia); 1013 1014 if (ia == NULL) { 1015 IFP_TO_IA(ifp, ia); 1016 if (ia == NULL) { 1017 ARP_STATINC(ARP_STAT_RCVNOINT); 1018 goto out; 1019 } 1020 } 1021 } 1022 1023 myaddr = ia->ia_addr.sin_addr; 1024 1025 /* XXX checks for bridge case? */ 1026 if (!memcmp(ar_sha(ah), CLLADDR(ifp->if_sadl), ifp->if_addrlen)) { 1027 ARP_STATINC(ARP_STAT_RCVLOCALSHA); 1028 goto out; /* it's from me, ignore it. */ 1029 } 1030 1031 /* XXX checks for bridge case? */ 1032 if (!memcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) { 1033 ARP_STATINC(ARP_STAT_RCVBCASTSHA); 1034 log(LOG_ERR, 1035 "%s: arp: link address is broadcast for IP address %s!\n", 1036 ifp->if_xname, in_fmtaddr(isaddr)); 1037 goto out; 1038 } 1039 1040 if (in_hosteq(isaddr, myaddr)) { 1041 ARP_STATINC(ARP_STAT_RCVLOCALSPA); 1042 log(LOG_ERR, 1043 "duplicate IP address %s sent from link address %s\n", 1044 in_fmtaddr(isaddr), lla_snprintf(ar_sha(ah), ah->ar_hln)); 1045 itaddr = myaddr; 1046 goto reply; 1047 } 1048 la = arplookup(m, &isaddr, in_hosteq(itaddr, myaddr), 0); 1049 if (la != NULL && (rt = la->la_rt) && (sdl = satosdl(rt->rt_gateway))) { 1050 if (sdl->sdl_alen && 1051 memcmp(ar_sha(ah), CLLADDR(sdl), sdl->sdl_alen)) { 1052 if (rt->rt_flags & RTF_STATIC) { 1053 ARP_STATINC(ARP_STAT_RCVOVERPERM); 1054 log(LOG_INFO, 1055 "%s tried to overwrite permanent arp info" 1056 " for %s\n", 1057 lla_snprintf(ar_sha(ah), ah->ar_hln), 1058 in_fmtaddr(isaddr)); 1059 goto out; 1060 } else if (rt->rt_ifp != ifp) { 1061 ARP_STATINC(ARP_STAT_RCVOVERINT); 1062 log(LOG_INFO, 1063 "%s on %s tried to overwrite " 1064 "arp info for %s on %s\n", 1065 lla_snprintf(ar_sha(ah), ah->ar_hln), 1066 ifp->if_xname, in_fmtaddr(isaddr), 1067 rt->rt_ifp->if_xname); 1068 goto out; 1069 } else { 1070 ARP_STATINC(ARP_STAT_RCVOVER); 1071 log(LOG_INFO, 1072 "arp info overwritten for %s by %s\n", 1073 in_fmtaddr(isaddr), 1074 lla_snprintf(ar_sha(ah), ah->ar_hln)); 1075 } 1076 } 1077 /* 1078 * sanity check for the address length. 1079 * XXX this does not work for protocols with variable address 1080 * length. -is 1081 */ 1082 if (sdl->sdl_alen && 1083 sdl->sdl_alen != ah->ar_hln) { 1084 ARP_STATINC(ARP_STAT_RCVLENCHG); 1085 log(LOG_WARNING, 1086 "arp from %s: new addr len %d, was %d", 1087 in_fmtaddr(isaddr), ah->ar_hln, sdl->sdl_alen); 1088 } 1089 if (ifp->if_addrlen != ah->ar_hln) { 1090 ARP_STATINC(ARP_STAT_RCVBADLEN); 1091 log(LOG_WARNING, 1092 "arp from %s: addr len: new %d, i/f %d (ignored)", 1093 in_fmtaddr(isaddr), ah->ar_hln, 1094 ifp->if_addrlen); 1095 goto reply; 1096 } 1097 #if NTOKEN > 0 1098 /* 1099 * XXX uses m_data and assumes the complete answer including 1100 * XXX token-ring headers is in the same buf 1101 */ 1102 if (ifp->if_type == IFT_ISO88025) { 1103 struct token_header *trh; 1104 1105 trh = (struct token_header *)M_TRHSTART(m); 1106 if (trh->token_shost[0] & TOKEN_RI_PRESENT) { 1107 struct token_rif *rif; 1108 size_t riflen; 1109 1110 rif = TOKEN_RIF(trh); 1111 riflen = (ntohs(rif->tr_rcf) & 1112 TOKEN_RCF_LEN_MASK) >> 8; 1113 1114 if (riflen > 2 && 1115 riflen < sizeof(struct token_rif) && 1116 (riflen & 1) == 0) { 1117 rif->tr_rcf ^= htons(TOKEN_RCF_DIRECTION); 1118 rif->tr_rcf &= htons(~TOKEN_RCF_BROADCAST_MASK); 1119 memcpy(TOKEN_RIF(la), rif, riflen); 1120 } 1121 } 1122 } 1123 #endif /* NTOKEN > 0 */ 1124 (void)sockaddr_dl_setaddr(sdl, sdl->sdl_len, ar_sha(ah), 1125 ah->ar_hln); 1126 if (rt->rt_expire) 1127 rt->rt_expire = time_second + arpt_keep; 1128 rt->rt_flags &= ~RTF_REJECT; 1129 la->la_asked = 0; 1130 1131 s = splnet(); 1132 mold = la->la_hold; 1133 la->la_hold = 0; 1134 splx(s); 1135 1136 if (mold) { 1137 ARP_STATINC(ARP_STAT_DFRSENT); 1138 (*ifp->if_output)(ifp, mold, rt_getkey(rt), rt); 1139 } 1140 } 1141 reply: 1142 if (op != ARPOP_REQUEST) { 1143 if (op == ARPOP_REPLY) 1144 ARP_STATINC(ARP_STAT_RCVREPLY); 1145 out: 1146 m_freem(m); 1147 return; 1148 } 1149 ARP_STATINC(ARP_STAT_RCVREQUEST); 1150 if (in_hosteq(itaddr, myaddr)) { 1151 /* I am the target */ 1152 tha = ar_tha(ah); 1153 if (tha) 1154 memcpy(tha, ar_sha(ah), ah->ar_hln); 1155 memcpy(ar_sha(ah), CLLADDR(ifp->if_sadl), ah->ar_hln); 1156 } else { 1157 la = arplookup(m, &itaddr, 0, SIN_PROXY); 1158 if (la == NULL) 1159 goto out; 1160 rt = la->la_rt; 1161 if (rt->rt_ifp->if_type == IFT_CARP && 1162 m->m_pkthdr.rcvif->if_type != IFT_CARP) 1163 goto out; 1164 tha = ar_tha(ah); 1165 if (tha) 1166 memcpy(tha, ar_sha(ah), ah->ar_hln); 1167 sdl = satosdl(rt->rt_gateway); 1168 memcpy(ar_sha(ah), CLLADDR(sdl), ah->ar_hln); 1169 } 1170 1171 memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln); 1172 memcpy(ar_spa(ah), &itaddr, ah->ar_pln); 1173 ah->ar_op = htons(ARPOP_REPLY); 1174 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 1175 switch (ifp->if_type) { 1176 case IFT_IEEE1394: 1177 /* 1178 * ieee1394 arp reply is broadcast 1179 */ 1180 m->m_flags &= ~M_MCAST; 1181 m->m_flags |= M_BCAST; 1182 m->m_len = sizeof(*ah) + (2 * ah->ar_pln) + ah->ar_hln; 1183 break; 1184 1185 default: 1186 m->m_flags &= ~(M_BCAST|M_MCAST); /* never reply by broadcast */ 1187 m->m_len = sizeof(*ah) + (2 * ah->ar_pln) + (2 * ah->ar_hln); 1188 break; 1189 } 1190 m->m_pkthdr.len = m->m_len; 1191 sa.sa_family = AF_ARP; 1192 sa.sa_len = 2; 1193 arps = ARP_STAT_GETREF(); 1194 arps[ARP_STAT_SNDTOTAL]++; 1195 arps[ARP_STAT_SNDREPLY]++; 1196 ARP_STAT_PUTREF(); 1197 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 1198 return; 1199 } 1200 1201 /* 1202 * Free an arp entry. 1203 */ 1204 static void arptfree(struct llinfo_arp *la) 1205 { 1206 struct rtentry *rt = la->la_rt; 1207 struct sockaddr_dl *sdl; 1208 1209 ARP_LOCK_CHECK(); 1210 1211 if (rt == NULL) 1212 panic("arptfree"); 1213 if (rt->rt_refcnt > 0 && (sdl = satosdl(rt->rt_gateway)) && 1214 sdl->sdl_family == AF_LINK) { 1215 sdl->sdl_alen = 0; 1216 la->la_asked = 0; 1217 rt->rt_flags &= ~RTF_REJECT; 1218 return; 1219 } 1220 rtrequest(RTM_DELETE, rt_getkey(rt), NULL, rt_mask(rt), 0, NULL); 1221 } 1222 1223 static struct llinfo_arp * 1224 arplookup(struct mbuf *m, const struct in_addr *addr, int create, int proxy) 1225 { 1226 return arplookup1(m, addr, create, proxy, NULL); 1227 } 1228 1229 /* 1230 * Lookup or enter a new address in arptab. 1231 */ 1232 static struct llinfo_arp * 1233 arplookup1(struct mbuf *m, const struct in_addr *addr, int create, int proxy, 1234 struct rtentry *rt0) 1235 { 1236 struct arphdr *ah; 1237 struct ifnet *ifp = m->m_pkthdr.rcvif; 1238 struct rtentry *rt; 1239 struct sockaddr_inarp sin; 1240 const char *why = NULL; 1241 1242 ah = mtod(m, struct arphdr *); 1243 if (rt0 == NULL) { 1244 memset(&sin, 0, sizeof(sin)); 1245 sin.sin_len = sizeof(sin); 1246 sin.sin_family = AF_INET; 1247 sin.sin_addr = *addr; 1248 sin.sin_other = proxy ? SIN_PROXY : 0; 1249 rt = rtalloc1(sintosa(&sin), create); 1250 if (rt == NULL) 1251 return NULL; 1252 rt->rt_refcnt--; 1253 } else 1254 rt = rt0; 1255 1256 #define IS_LLINFO(__rt) \ 1257 (((__rt)->rt_flags & (RTF_GATEWAY | RTF_LLINFO)) == RTF_LLINFO && \ 1258 (__rt)->rt_gateway->sa_family == AF_LINK) 1259 1260 1261 if (IS_LLINFO(rt)) 1262 return (struct llinfo_arp *)rt->rt_llinfo; 1263 1264 if (create) { 1265 if (rt->rt_flags & RTF_GATEWAY) 1266 why = "host is not on local network"; 1267 else if ((rt->rt_flags & RTF_LLINFO) == 0) { 1268 ARP_STATINC(ARP_STAT_ALLOCFAIL); 1269 why = "could not allocate llinfo"; 1270 } else 1271 why = "gateway route is not ours"; 1272 log(LOG_DEBUG, "arplookup: unable to enter address" 1273 " for %s@%s on %s (%s)\n", 1274 in_fmtaddr(*addr), lla_snprintf(ar_sha(ah), ah->ar_hln), 1275 (ifp) ? ifp->if_xname : "null", why); 1276 if (rt->rt_refcnt <= 0 && (rt->rt_flags & RTF_CLONED) != 0) { 1277 rtrequest(RTM_DELETE, rt_getkey(rt), 1278 rt->rt_gateway, rt_mask(rt), rt->rt_flags, NULL); 1279 } 1280 } 1281 return NULL; 1282 } 1283 1284 int 1285 arpioctl(u_long cmd, void *data) 1286 { 1287 1288 return EOPNOTSUPP; 1289 } 1290 1291 void 1292 arp_ifinit(struct ifnet *ifp, struct ifaddr *ifa) 1293 { 1294 struct in_addr *ip; 1295 1296 /* 1297 * Warn the user if another station has this IP address, 1298 * but only if the interface IP address is not zero. 1299 */ 1300 ip = &IA_SIN(ifa)->sin_addr; 1301 if (!in_nullhost(*ip)) 1302 arprequest(ifp, ip, ip, CLLADDR(ifp->if_sadl)); 1303 1304 ifa->ifa_rtrequest = arp_rtrequest; 1305 ifa->ifa_flags |= RTF_CLONING; 1306 } 1307 1308 /* 1309 * Called from 10 Mb/s Ethernet interrupt handlers 1310 * when ether packet type ETHERTYPE_REVARP 1311 * is received. Common length and type checks are done here, 1312 * then the protocol-specific routine is called. 1313 */ 1314 void 1315 revarpinput(struct mbuf *m) 1316 { 1317 struct arphdr *ar; 1318 1319 if (m->m_len < sizeof(struct arphdr)) 1320 goto out; 1321 ar = mtod(m, struct arphdr *); 1322 #if 0 /* XXX I don't think we need this... and it will prevent other LL */ 1323 if (ntohs(ar->ar_hrd) != ARPHRD_ETHER) 1324 goto out; 1325 #endif 1326 if (m->m_len < sizeof(struct arphdr) + 2 * (ar->ar_hln + ar->ar_pln)) 1327 goto out; 1328 switch (ntohs(ar->ar_pro)) { 1329 case ETHERTYPE_IP: 1330 case ETHERTYPE_IPTRAILERS: 1331 in_revarpinput(m); 1332 return; 1333 1334 default: 1335 break; 1336 } 1337 out: 1338 m_freem(m); 1339 } 1340 1341 /* 1342 * RARP for Internet protocols on 10 Mb/s Ethernet. 1343 * Algorithm is that given in RFC 903. 1344 * We are only using for bootstrap purposes to get an ip address for one of 1345 * our interfaces. Thus we support no user-interface. 1346 * 1347 * Since the contents of the RARP reply are specific to the interface that 1348 * sent the request, this code must ensure that they are properly associated. 1349 * 1350 * Note: also supports ARP via RARP packets, per the RFC. 1351 */ 1352 void 1353 in_revarpinput(struct mbuf *m) 1354 { 1355 struct ifnet *ifp; 1356 struct arphdr *ah; 1357 void *tha; 1358 int op; 1359 1360 ah = mtod(m, struct arphdr *); 1361 op = ntohs(ah->ar_op); 1362 1363 switch (m->m_pkthdr.rcvif->if_type) { 1364 case IFT_IEEE1394: 1365 /* ARP without target hardware address is not supported */ 1366 goto out; 1367 default: 1368 break; 1369 } 1370 1371 switch (op) { 1372 case ARPOP_REQUEST: 1373 case ARPOP_REPLY: /* per RFC */ 1374 in_arpinput(m); 1375 return; 1376 case ARPOP_REVREPLY: 1377 break; 1378 case ARPOP_REVREQUEST: /* handled by rarpd(8) */ 1379 default: 1380 goto out; 1381 } 1382 if (!revarp_in_progress) 1383 goto out; 1384 ifp = m->m_pkthdr.rcvif; 1385 if (ifp != myip_ifp) /* !same interface */ 1386 goto out; 1387 if (myip_initialized) 1388 goto wake; 1389 tha = ar_tha(ah); 1390 KASSERT(tha); 1391 if (memcmp(tha, CLLADDR(ifp->if_sadl), ifp->if_sadl->sdl_alen)) 1392 goto out; 1393 memcpy(&srv_ip, ar_spa(ah), sizeof(srv_ip)); 1394 memcpy(&myip, ar_tpa(ah), sizeof(myip)); 1395 myip_initialized = 1; 1396 wake: /* Do wakeup every time in case it was missed. */ 1397 wakeup((void *)&myip); 1398 1399 out: 1400 m_freem(m); 1401 } 1402 1403 /* 1404 * Send a RARP request for the ip address of the specified interface. 1405 * The request should be RFC 903-compliant. 1406 */ 1407 void 1408 revarprequest(struct ifnet *ifp) 1409 { 1410 struct sockaddr sa; 1411 struct mbuf *m; 1412 struct arphdr *ah; 1413 void *tha; 1414 1415 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 1416 return; 1417 MCLAIM(m, &arpdomain.dom_mowner); 1418 m->m_len = sizeof(*ah) + 2*sizeof(struct in_addr) + 1419 2*ifp->if_addrlen; 1420 m->m_pkthdr.len = m->m_len; 1421 MH_ALIGN(m, m->m_len); 1422 ah = mtod(m, struct arphdr *); 1423 memset(ah, 0, m->m_len); 1424 ah->ar_pro = htons(ETHERTYPE_IP); 1425 ah->ar_hln = ifp->if_addrlen; /* hardware address length */ 1426 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 1427 ah->ar_op = htons(ARPOP_REVREQUEST); 1428 1429 memcpy(ar_sha(ah), CLLADDR(ifp->if_sadl), ah->ar_hln); 1430 tha = ar_tha(ah); 1431 KASSERT(tha); 1432 memcpy(tha, CLLADDR(ifp->if_sadl), ah->ar_hln); 1433 1434 sa.sa_family = AF_ARP; 1435 sa.sa_len = 2; 1436 m->m_flags |= M_BCAST; 1437 (*ifp->if_output)(ifp, m, &sa, NULL); 1438 1439 } 1440 1441 /* 1442 * RARP for the ip address of the specified interface, but also 1443 * save the ip address of the server that sent the answer. 1444 * Timeout if no response is received. 1445 */ 1446 int 1447 revarpwhoarewe(struct ifnet *ifp, struct in_addr *serv_in, 1448 struct in_addr *clnt_in) 1449 { 1450 int result, count = 20; 1451 1452 myip_initialized = 0; 1453 myip_ifp = ifp; 1454 1455 revarp_in_progress = 1; 1456 while (count--) { 1457 revarprequest(ifp); 1458 result = tsleep((void *)&myip, PSOCK, "revarp", hz/2); 1459 if (result != EWOULDBLOCK) 1460 break; 1461 } 1462 revarp_in_progress = 0; 1463 1464 if (!myip_initialized) 1465 return ENETUNREACH; 1466 1467 memcpy(serv_in, &srv_ip, sizeof(*serv_in)); 1468 memcpy(clnt_in, &myip, sizeof(*clnt_in)); 1469 return 0; 1470 } 1471 1472 1473 1474 #ifdef DDB 1475 1476 #include <machine/db_machdep.h> 1477 #include <ddb/db_interface.h> 1478 #include <ddb/db_output.h> 1479 1480 static void 1481 db_print_sa(const struct sockaddr *sa) 1482 { 1483 int len; 1484 const u_char *p; 1485 1486 if (sa == NULL) { 1487 db_printf("[NULL]"); 1488 return; 1489 } 1490 1491 p = (const u_char *)sa; 1492 len = sa->sa_len; 1493 db_printf("["); 1494 while (len > 0) { 1495 db_printf("%d", *p); 1496 p++; len--; 1497 if (len) db_printf(","); 1498 } 1499 db_printf("]\n"); 1500 } 1501 1502 static void 1503 db_print_ifa(struct ifaddr *ifa) 1504 { 1505 if (ifa == NULL) 1506 return; 1507 db_printf(" ifa_addr="); 1508 db_print_sa(ifa->ifa_addr); 1509 db_printf(" ifa_dsta="); 1510 db_print_sa(ifa->ifa_dstaddr); 1511 db_printf(" ifa_mask="); 1512 db_print_sa(ifa->ifa_netmask); 1513 db_printf(" flags=0x%x,refcnt=%d,metric=%d\n", 1514 ifa->ifa_flags, 1515 ifa->ifa_refcnt, 1516 ifa->ifa_metric); 1517 } 1518 1519 static void 1520 db_print_llinfo(void *li) 1521 { 1522 struct llinfo_arp *la; 1523 1524 if (li == NULL) 1525 return; 1526 la = (struct llinfo_arp *)li; 1527 db_printf(" la_rt=%p la_hold=%p, la_asked=0x%lx\n", 1528 la->la_rt, la->la_hold, la->la_asked); 1529 } 1530 1531 /* 1532 * Function to pass to rt_walktree(). 1533 * Return non-zero error to abort walk. 1534 */ 1535 static int 1536 db_show_rtentry(struct rtentry *rt, void *w) 1537 { 1538 db_printf("rtentry=%p", rt); 1539 1540 db_printf(" flags=0x%x refcnt=%d use=%ld expire=%ld\n", 1541 rt->rt_flags, rt->rt_refcnt, 1542 rt->rt_use, rt->rt_expire); 1543 1544 db_printf(" key="); db_print_sa(rt_getkey(rt)); 1545 db_printf(" mask="); db_print_sa(rt_mask(rt)); 1546 db_printf(" gw="); db_print_sa(rt->rt_gateway); 1547 1548 db_printf(" ifp=%p ", rt->rt_ifp); 1549 if (rt->rt_ifp) 1550 db_printf("(%s)", rt->rt_ifp->if_xname); 1551 else 1552 db_printf("(NULL)"); 1553 1554 db_printf(" ifa=%p\n", rt->rt_ifa); 1555 db_print_ifa(rt->rt_ifa); 1556 1557 db_printf(" gwroute=%p llinfo=%p\n", 1558 rt->rt_gwroute, rt->rt_llinfo); 1559 db_print_llinfo(rt->rt_llinfo); 1560 1561 return 0; 1562 } 1563 1564 /* 1565 * Function to print all the route trees. 1566 * Use this from ddb: "show arptab" 1567 */ 1568 void 1569 db_show_arptab(db_expr_t addr, bool have_addr, 1570 db_expr_t count, const char *modif) 1571 { 1572 rt_walktree(AF_INET, db_show_rtentry, NULL); 1573 } 1574 #endif 1575 1576 static int 1577 sysctl_net_inet_arp_stats(SYSCTLFN_ARGS) 1578 { 1579 1580 return NETSTAT_SYSCTL(arpstat_percpu, ARP_NSTATS); 1581 } 1582 1583 SYSCTL_SETUP(sysctl_net_inet_arp_setup, "sysctl net.inet.arp subtree setup") 1584 { 1585 const struct sysctlnode *node; 1586 1587 sysctl_createv(clog, 0, NULL, NULL, 1588 CTLFLAG_PERMANENT, 1589 CTLTYPE_NODE, "net", NULL, 1590 NULL, 0, NULL, 0, 1591 CTL_NET, CTL_EOL); 1592 sysctl_createv(clog, 0, NULL, NULL, 1593 CTLFLAG_PERMANENT, 1594 CTLTYPE_NODE, "inet", NULL, 1595 NULL, 0, NULL, 0, 1596 CTL_NET, PF_INET, CTL_EOL); 1597 sysctl_createv(clog, 0, NULL, &node, 1598 CTLFLAG_PERMANENT, 1599 CTLTYPE_NODE, "arp", 1600 SYSCTL_DESCR("Address Resolution Protocol"), 1601 NULL, 0, NULL, 0, 1602 CTL_NET, PF_INET, CTL_CREATE, CTL_EOL); 1603 1604 sysctl_createv(clog, 0, NULL, NULL, 1605 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1606 CTLTYPE_INT, "prune", 1607 SYSCTL_DESCR("ARP cache pruning interval"), 1608 NULL, 0, &arpt_prune, 0, 1609 CTL_NET,PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL); 1610 1611 sysctl_createv(clog, 0, NULL, NULL, 1612 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1613 CTLTYPE_INT, "keep", 1614 SYSCTL_DESCR("Valid ARP entry lifetime"), 1615 NULL, 0, &arpt_keep, 0, 1616 CTL_NET,PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL); 1617 1618 sysctl_createv(clog, 0, NULL, NULL, 1619 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1620 CTLTYPE_INT, "down", 1621 SYSCTL_DESCR("Failed ARP entry lifetime"), 1622 NULL, 0, &arpt_down, 0, 1623 CTL_NET,PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL); 1624 1625 sysctl_createv(clog, 0, NULL, NULL, 1626 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1627 CTLTYPE_INT, "refresh", 1628 SYSCTL_DESCR("ARP entry refresh interval"), 1629 NULL, 0, &arpt_refresh, 0, 1630 CTL_NET,PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL); 1631 1632 sysctl_createv(clog, 0, NULL, NULL, 1633 CTLFLAG_PERMANENT, 1634 CTLTYPE_STRUCT, "stats", 1635 SYSCTL_DESCR("ARP statistics"), 1636 sysctl_net_inet_arp_stats, 0, NULL, 0, 1637 CTL_NET,PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL); 1638 } 1639 1640 #endif /* INET */ 1641