1 /* $NetBSD: if_arp.c,v 1.131 2008/01/20 18:09:12 joerg Exp $ */ 2 3 /*- 4 * Copyright (c) 1998, 2000 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 * 3. All advertising materials mentioning features or use of this software 20 * must display the following acknowledgement: 21 * This product includes software developed by the NetBSD 22 * Foundation, Inc. and its contributors. 23 * 4. Neither the name of The NetBSD Foundation nor the names of its 24 * contributors may be used to endorse or promote products derived 25 * from this software without specific prior written permission. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 28 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 29 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 30 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 31 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 32 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 33 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 34 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 35 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 36 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 37 * POSSIBILITY OF SUCH DAMAGE. 38 */ 39 40 /* 41 * Copyright (c) 1982, 1986, 1988, 1993 42 * The Regents of the University of California. All rights reserved. 43 * 44 * Redistribution and use in source and binary forms, with or without 45 * modification, are permitted provided that the following conditions 46 * are met: 47 * 1. Redistributions of source code must retain the above copyright 48 * notice, this list of conditions and the following disclaimer. 49 * 2. Redistributions in binary form must reproduce the above copyright 50 * notice, this list of conditions and the following disclaimer in the 51 * documentation and/or other materials provided with the distribution. 52 * 3. Neither the name of the University nor the names of its contributors 53 * may be used to endorse or promote products derived from this software 54 * without specific prior written permission. 55 * 56 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 57 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 58 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 59 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 60 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 61 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 62 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 63 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 64 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 65 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 66 * SUCH DAMAGE. 67 * 68 * @(#)if_ether.c 8.2 (Berkeley) 9/26/94 69 */ 70 71 /* 72 * Ethernet address resolution protocol. 73 * TODO: 74 * add "inuse/lock" bit (or ref. count) along with valid bit 75 */ 76 77 #include <sys/cdefs.h> 78 __KERNEL_RCSID(0, "$NetBSD: if_arp.c,v 1.131 2008/01/20 18:09:12 joerg Exp $"); 79 80 #include "opt_ddb.h" 81 #include "opt_inet.h" 82 83 #ifdef INET 84 85 #include "bridge.h" 86 87 #include <sys/param.h> 88 #include <sys/systm.h> 89 #include <sys/callout.h> 90 #include <sys/malloc.h> 91 #include <sys/mbuf.h> 92 #include <sys/socket.h> 93 #include <sys/time.h> 94 #include <sys/timetc.h> 95 #include <sys/kernel.h> 96 #include <sys/errno.h> 97 #include <sys/ioctl.h> 98 #include <sys/syslog.h> 99 #include <sys/proc.h> 100 #include <sys/protosw.h> 101 #include <sys/domain.h> 102 #include <sys/sysctl.h> 103 104 #include <net/ethertypes.h> 105 #include <net/if.h> 106 #include <net/if_dl.h> 107 #include <net/if_token.h> 108 #include <net/if_types.h> 109 #include <net/if_ether.h> 110 #include <net/route.h> 111 112 #include <netinet/in.h> 113 #include <netinet/in_systm.h> 114 #include <netinet/in_var.h> 115 #include <netinet/ip.h> 116 #include <netinet/if_inarp.h> 117 118 #include "arcnet.h" 119 #if NARCNET > 0 120 #include <net/if_arc.h> 121 #endif 122 #include "fddi.h" 123 #if NFDDI > 0 124 #include <net/if_fddi.h> 125 #endif 126 #include "token.h" 127 #include "carp.h" 128 #if NCARP > 0 129 #include <netinet/ip_carp.h> 130 #endif 131 132 #define SIN(s) ((struct sockaddr_in *)s) 133 #define SRP(s) ((struct sockaddr_inarp *)s) 134 135 /* 136 * ARP trailer negotiation. Trailer protocol is not IP specific, 137 * but ARP request/response use IP addresses. 138 */ 139 #define ETHERTYPE_IPTRAILERS ETHERTYPE_TRAIL 140 141 /* timer values */ 142 int arpt_prune = (5*60*1); /* walk list every 5 minutes */ 143 int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */ 144 int arpt_down = 20; /* once declared down, don't send for 20 secs */ 145 int arpt_refresh = (5*60); /* time left before refreshing */ 146 #define rt_expire rt_rmx.rmx_expire 147 #define rt_pksent rt_rmx.rmx_pksent 148 149 static struct sockaddr *arp_setgate(struct rtentry *, struct sockaddr *, 150 const struct sockaddr *); 151 static void arptfree(struct llinfo_arp *); 152 static void arptimer(void *); 153 static struct llinfo_arp *arplookup1(struct mbuf *, const struct in_addr *, 154 int, int, struct rtentry *); 155 static struct llinfo_arp *arplookup(struct mbuf *, const struct in_addr *, 156 int, int); 157 static void in_arpinput(struct mbuf *); 158 159 LIST_HEAD(, llinfo_arp) llinfo_arp; 160 struct ifqueue arpintrq = { 161 .ifq_head = NULL, 162 .ifq_tail = NULL, 163 .ifq_len = 0, 164 .ifq_maxlen = 50, 165 .ifq_drops = 0, 166 }; 167 int arp_inuse, arp_allocated, arp_intimer; 168 int arp_maxtries = 5; 169 int useloopback = 1; /* use loopback interface for local traffic */ 170 int arpinit_done = 0; 171 172 struct arpstat arpstat; 173 struct callout arptimer_ch; 174 175 /* revarp state */ 176 struct in_addr myip, srv_ip; 177 int myip_initialized = 0; 178 int revarp_in_progress = 0; 179 struct ifnet *myip_ifp = NULL; 180 181 #ifdef DDB 182 static void db_print_sa(const struct sockaddr *); 183 static void db_print_ifa(struct ifaddr *); 184 static void db_print_llinfo(void *); 185 static int db_show_rtentry(struct rtentry *, void *); 186 #endif 187 188 /* 189 * this should be elsewhere. 190 */ 191 192 static char * 193 lla_snprintf(u_int8_t *, int); 194 195 static char * 196 lla_snprintf(u_int8_t *adrp, int len) 197 { 198 #define NUMBUFS 3 199 static char buf[NUMBUFS][16*3]; 200 static int bnum = 0; 201 202 int i; 203 char *p; 204 205 p = buf[bnum]; 206 207 *p++ = hexdigits[(*adrp)>>4]; 208 *p++ = hexdigits[(*adrp++)&0xf]; 209 210 for (i=1; i<len && i<16; i++) { 211 *p++ = ':'; 212 *p++ = hexdigits[(*adrp)>>4]; 213 *p++ = hexdigits[(*adrp++)&0xf]; 214 } 215 216 *p = 0; 217 p = buf[bnum]; 218 bnum = (bnum + 1) % NUMBUFS; 219 return p; 220 } 221 222 DOMAIN_DEFINE(arpdomain); /* forward declare and add to link set */ 223 224 const struct protosw arpsw[] = { 225 { .pr_type = 0, 226 .pr_domain = &arpdomain, 227 .pr_protocol = 0, 228 .pr_flags = 0, 229 .pr_input = 0, 230 .pr_output = 0, 231 .pr_ctlinput = 0, 232 .pr_ctloutput = 0, 233 .pr_usrreq = 0, 234 .pr_init = 0, 235 .pr_fasttimo = 0, 236 .pr_slowtimo = 0, 237 .pr_drain = arp_drain, 238 } 239 }; 240 241 242 struct domain arpdomain = { 243 .dom_family = PF_ARP, 244 .dom_name = "arp", 245 .dom_protosw = arpsw, 246 .dom_protoswNPROTOSW = &arpsw[sizeof(arpsw)/sizeof(arpsw[0])], 247 }; 248 249 /* 250 * ARP table locking. 251 * 252 * to prevent lossage vs. the arp_drain routine (which may be called at 253 * any time, including in a device driver context), we do two things: 254 * 255 * 1) manipulation of la->la_hold is done at splnet() (for all of 256 * about two instructions). 257 * 258 * 2) manipulation of the arp table's linked list is done under the 259 * protection of the ARP_LOCK; if arp_drain() or arptimer is called 260 * while the arp table is locked, we punt and try again later. 261 */ 262 263 static int arp_locked; 264 static inline int arp_lock_try(int); 265 static inline void arp_unlock(void); 266 267 static inline int 268 arp_lock_try(int recurse) 269 { 270 int s; 271 272 /* 273 * Use splvm() -- we're blocking things that would cause 274 * mbuf allocation. 275 */ 276 s = splvm(); 277 if (!recurse && arp_locked) { 278 splx(s); 279 return (0); 280 } 281 arp_locked++; 282 splx(s); 283 return (1); 284 } 285 286 static inline void 287 arp_unlock(void) 288 { 289 int s; 290 291 s = splvm(); 292 arp_locked--; 293 splx(s); 294 } 295 296 #ifdef DIAGNOSTIC 297 #define ARP_LOCK(recurse) \ 298 do { \ 299 if (arp_lock_try(recurse) == 0) { \ 300 printf("%s:%d: arp already locked\n", __FILE__, __LINE__); \ 301 panic("arp_lock"); \ 302 } \ 303 } while (/*CONSTCOND*/ 0) 304 #define ARP_LOCK_CHECK() \ 305 do { \ 306 if (arp_locked == 0) { \ 307 printf("%s:%d: arp lock not held\n", __FILE__, __LINE__); \ 308 panic("arp lock check"); \ 309 } \ 310 } while (/*CONSTCOND*/ 0) 311 #else 312 #define ARP_LOCK(x) (void) arp_lock_try(x) 313 #define ARP_LOCK_CHECK() /* nothing */ 314 #endif 315 316 #define ARP_UNLOCK() arp_unlock() 317 318 /* 319 * ARP protocol drain routine. Called when memory is in short supply. 320 * Called at splvm(); 321 */ 322 323 void 324 arp_drain(void) 325 { 326 struct llinfo_arp *la, *nla; 327 int count = 0; 328 struct mbuf *mold; 329 330 if (arp_lock_try(0) == 0) { 331 printf("arp_drain: locked; punting\n"); 332 return; 333 } 334 335 for (la = LIST_FIRST(&llinfo_arp); la != 0; la = nla) { 336 nla = LIST_NEXT(la, la_list); 337 338 mold = la->la_hold; 339 la->la_hold = 0; 340 341 if (mold) { 342 m_freem(mold); 343 count++; 344 } 345 } 346 ARP_UNLOCK(); 347 arpstat.as_dfrdropped += count; 348 } 349 350 351 /* 352 * Timeout routine. Age arp_tab entries periodically. 353 */ 354 /* ARGSUSED */ 355 static void 356 arptimer(void *arg) 357 { 358 int s; 359 struct llinfo_arp *la, *nla; 360 361 s = splsoftnet(); 362 363 if (arp_lock_try(0) == 0) { 364 /* get it later.. */ 365 splx(s); 366 return; 367 } 368 369 callout_reset(&arptimer_ch, arpt_prune * hz, arptimer, NULL); 370 for (la = LIST_FIRST(&llinfo_arp); la != 0; la = nla) { 371 struct rtentry *rt = la->la_rt; 372 373 nla = LIST_NEXT(la, la_list); 374 if (rt->rt_expire == 0) 375 continue; 376 if ((rt->rt_expire - time_second) < arpt_refresh && 377 rt->rt_pksent > (time_second - arpt_keep)) { 378 /* 379 * If the entry has been used during since last 380 * refresh, try to renew it before deleting. 381 */ 382 arprequest(rt->rt_ifp, 383 &satocsin(rt->rt_ifa->ifa_addr)->sin_addr, 384 &satocsin(rt_getkey(rt))->sin_addr, 385 CLLADDR(rt->rt_ifp->if_sadl)); 386 } else if (rt->rt_expire <= time_second) 387 arptfree(la); /* timer has expired; clear */ 388 } 389 390 ARP_UNLOCK(); 391 392 splx(s); 393 } 394 395 /* 396 * We set the gateway for RTF_CLONING routes to a "prototype" 397 * link-layer sockaddr whose interface type (if_type) and interface 398 * index (if_index) fields are prepared. 399 */ 400 static struct sockaddr * 401 arp_setgate(struct rtentry *rt, struct sockaddr *gate, 402 const struct sockaddr *netmask) 403 { 404 const struct ifnet *ifp = rt->rt_ifp; 405 uint8_t namelen = strlen(ifp->if_xname); 406 uint8_t addrlen = ifp->if_addrlen; 407 408 /* 409 * XXX: If this is a manually added route to interface 410 * such as older version of routed or gated might provide, 411 * restore cloning bit. 412 */ 413 if ((rt->rt_flags & RTF_HOST) == 0 && netmask != NULL && 414 satocsin(netmask)->sin_addr.s_addr != 0xffffffff) 415 rt->rt_flags |= RTF_CLONING; 416 if (rt->rt_flags & RTF_CLONING) { 417 union { 418 struct sockaddr sa; 419 struct sockaddr_storage ss; 420 struct sockaddr_dl sdl; 421 } u; 422 /* 423 * Case 1: This route should come from a route to iface. 424 */ 425 sockaddr_dl_init(&u.sdl, sizeof(u.ss), 426 ifp->if_index, ifp->if_type, NULL, namelen, NULL, addrlen); 427 rt_setgate(rt, &u.sa); 428 gate = rt->rt_gateway; 429 } 430 return gate; 431 } 432 433 /* 434 * Parallel to llc_rtrequest. 435 */ 436 void 437 arp_rtrequest(int req, struct rtentry *rt, struct rt_addrinfo *info) 438 { 439 struct sockaddr *gate = rt->rt_gateway; 440 struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo; 441 size_t allocsize; 442 struct mbuf *mold; 443 int s; 444 struct in_ifaddr *ia; 445 struct ifaddr *ifa; 446 struct ifnet *ifp = rt->rt_ifp; 447 uint8_t namelen = strlen(ifp->if_xname); 448 uint8_t addrlen = ifp->if_addrlen; 449 450 if (!arpinit_done) { 451 arpinit_done = 1; 452 /* 453 * We generate expiration times from time_second 454 * so avoid accidentally creating permanent routes. 455 */ 456 if (time_second == 0) { 457 struct timespec ts; 458 ts.tv_sec = 1; 459 ts.tv_nsec = 0; 460 tc_setclock(&ts); 461 } 462 callout_init(&arptimer_ch, 0); 463 callout_reset(&arptimer_ch, hz, arptimer, NULL); 464 } 465 466 if ((rt->rt_flags & RTF_GATEWAY) != 0) { 467 if (req != RTM_ADD) 468 return; 469 470 /* 471 * linklayers with particular link MTU limitation. 472 */ 473 switch(ifp->if_type) { 474 #if NFDDI > 0 475 case IFT_FDDI: 476 if (ifp->if_mtu > FDDIIPMTU) 477 rt->rt_rmx.rmx_mtu = FDDIIPMTU; 478 break; 479 #endif 480 #if NARC > 0 481 case IFT_ARCNET: 482 { 483 int arcipifmtu; 484 485 if (ifp->if_flags & IFF_LINK0) 486 arcipifmtu = arc_ipmtu; 487 else 488 arcipifmtu = ARCMTU; 489 if (ifp->if_mtu > arcipifmtu) 490 rt->rt_rmx.rmx_mtu = arcipifmtu; 491 break; 492 } 493 #endif 494 } 495 return; 496 } 497 498 ARP_LOCK(1); /* we may already be locked here. */ 499 500 switch (req) { 501 502 case RTM_SETGATE: 503 gate = arp_setgate(rt, gate, info->rti_info[RTAX_NETMASK]); 504 break; 505 case RTM_ADD: 506 gate = arp_setgate(rt, gate, info->rti_info[RTAX_NETMASK]); 507 if (rt->rt_flags & RTF_CLONING) { 508 /* 509 * Give this route an expiration time, even though 510 * it's a "permanent" route, so that routes cloned 511 * from it do not need their expiration time set. 512 */ 513 rt->rt_expire = time_second; 514 /* 515 * linklayers with particular link MTU limitation. 516 */ 517 switch (ifp->if_type) { 518 #if NFDDI > 0 519 case IFT_FDDI: 520 if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0 && 521 (rt->rt_rmx.rmx_mtu > FDDIIPMTU || 522 (rt->rt_rmx.rmx_mtu == 0 && 523 ifp->if_mtu > FDDIIPMTU))) 524 rt->rt_rmx.rmx_mtu = FDDIIPMTU; 525 break; 526 #endif 527 #if NARC > 0 528 case IFT_ARCNET: 529 { 530 int arcipifmtu; 531 if (ifp->if_flags & IFF_LINK0) 532 arcipifmtu = arc_ipmtu; 533 else 534 arcipifmtu = ARCMTU; 535 536 if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0 && 537 (rt->rt_rmx.rmx_mtu > arcipifmtu || 538 (rt->rt_rmx.rmx_mtu == 0 && 539 ifp->if_mtu > arcipifmtu))) 540 rt->rt_rmx.rmx_mtu = arcipifmtu; 541 break; 542 } 543 #endif 544 } 545 break; 546 } 547 /* Announce a new entry if requested. */ 548 if (rt->rt_flags & RTF_ANNOUNCE) 549 arprequest(ifp, 550 &satocsin(rt_getkey(rt))->sin_addr, 551 &satocsin(rt_getkey(rt))->sin_addr, 552 CLLADDR(satocsdl(gate))); 553 /*FALLTHROUGH*/ 554 case RTM_RESOLVE: 555 if (gate->sa_family != AF_LINK || 556 gate->sa_len < sockaddr_dl_measure(namelen, addrlen)) { 557 log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n"); 558 break; 559 } 560 satosdl(gate)->sdl_type = ifp->if_type; 561 satosdl(gate)->sdl_index = ifp->if_index; 562 if (la != 0) 563 break; /* This happens on a route change */ 564 /* 565 * Case 2: This route may come from cloning, or a manual route 566 * add with a LL address. 567 */ 568 switch (satocsdl(gate)->sdl_type) { 569 #if NTOKEN > 0 570 case IFT_ISO88025: 571 allocsize = sizeof(*la) + sizeof(struct token_rif); 572 break; 573 #endif /* NTOKEN > 0 */ 574 default: 575 allocsize = sizeof(*la); 576 } 577 R_Malloc(la, struct llinfo_arp *, allocsize); 578 rt->rt_llinfo = (void *)la; 579 if (la == 0) { 580 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); 581 break; 582 } 583 arp_inuse++, arp_allocated++; 584 Bzero(la, allocsize); 585 la->la_rt = rt; 586 rt->rt_flags |= RTF_LLINFO; 587 LIST_INSERT_HEAD(&llinfo_arp, la, la_list); 588 589 INADDR_TO_IA(satocsin(rt_getkey(rt))->sin_addr, ia); 590 while (ia && ia->ia_ifp != ifp) 591 NEXT_IA_WITH_SAME_ADDR(ia); 592 if (ia) { 593 /* 594 * This test used to be 595 * if (lo0ifp->if_flags & IFF_UP) 596 * It allowed local traffic to be forced through 597 * the hardware by configuring the loopback down. 598 * However, it causes problems during network 599 * configuration for boards that can't receive 600 * packets they send. It is now necessary to clear 601 * "useloopback" and remove the route to force 602 * traffic out to the hardware. 603 * 604 * In 4.4BSD, the above "if" statement checked 605 * rt->rt_ifa against rt_getkey(rt). It was changed 606 * to the current form so that we can provide a 607 * better support for multiple IPv4 addresses on a 608 * interface. 609 */ 610 rt->rt_expire = 0; 611 (void)sockaddr_dl_setaddr(satosdl(gate), gate->sa_len, 612 CLLADDR(ifp->if_sadl), ifp->if_addrlen); 613 if (useloopback) 614 ifp = rt->rt_ifp = lo0ifp; 615 /* 616 * make sure to set rt->rt_ifa to the interface 617 * address we are using, otherwise we will have trouble 618 * with source address selection. 619 */ 620 ifa = &ia->ia_ifa; 621 if (ifa != rt->rt_ifa) 622 rt_replace_ifa(rt, ifa); 623 } 624 break; 625 626 case RTM_DELETE: 627 if (la == 0) 628 break; 629 arp_inuse--; 630 LIST_REMOVE(la, la_list); 631 rt->rt_llinfo = 0; 632 rt->rt_flags &= ~RTF_LLINFO; 633 634 s = splnet(); 635 mold = la->la_hold; 636 la->la_hold = 0; 637 splx(s); 638 639 if (mold) 640 m_freem(mold); 641 642 Free((void *)la); 643 } 644 ARP_UNLOCK(); 645 } 646 647 /* 648 * Broadcast an ARP request. Caller specifies: 649 * - arp header source ip address 650 * - arp header target ip address 651 * - arp header source ethernet address 652 */ 653 void 654 arprequest(struct ifnet *ifp, 655 const struct in_addr *sip, const struct in_addr *tip, 656 const u_int8_t *enaddr) 657 { 658 struct mbuf *m; 659 struct arphdr *ah; 660 struct sockaddr sa; 661 662 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 663 return; 664 MCLAIM(m, &arpdomain.dom_mowner); 665 switch (ifp->if_type) { 666 case IFT_IEEE1394: 667 m->m_len = sizeof(*ah) + 2 * sizeof(struct in_addr) + 668 ifp->if_addrlen; 669 break; 670 default: 671 m->m_len = sizeof(*ah) + 2 * sizeof(struct in_addr) + 672 2 * ifp->if_addrlen; 673 break; 674 } 675 m->m_pkthdr.len = m->m_len; 676 MH_ALIGN(m, m->m_len); 677 ah = mtod(m, struct arphdr *); 678 bzero((void *)ah, m->m_len); 679 switch (ifp->if_type) { 680 case IFT_IEEE1394: /* RFC2734 */ 681 /* fill it now for ar_tpa computation */ 682 ah->ar_hrd = htons(ARPHRD_IEEE1394); 683 break; 684 default: 685 /* ifp->if_output will fill ar_hrd */ 686 break; 687 } 688 ah->ar_pro = htons(ETHERTYPE_IP); 689 ah->ar_hln = ifp->if_addrlen; /* hardware address length */ 690 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 691 ah->ar_op = htons(ARPOP_REQUEST); 692 memcpy(ar_sha(ah), enaddr, ah->ar_hln); 693 memcpy(ar_spa(ah), sip, ah->ar_pln); 694 memcpy(ar_tpa(ah), tip, ah->ar_pln); 695 sa.sa_family = AF_ARP; 696 sa.sa_len = 2; 697 m->m_flags |= M_BCAST; 698 arpstat.as_sndtotal++; 699 arpstat.as_sndrequest++; 700 (*ifp->if_output)(ifp, m, &sa, NULL); 701 } 702 703 /* 704 * Resolve an IP address into an ethernet address. If success, 705 * desten is filled in. If there is no entry in arptab, 706 * set one up and broadcast a request for the IP address. 707 * Hold onto this mbuf and resend it once the address 708 * is finally resolved. A return value of 1 indicates 709 * that desten has been filled in and the packet should be sent 710 * normally; a 0 return indicates that the packet has been 711 * taken over here, either now or for later transmission. 712 */ 713 int 714 arpresolve(struct ifnet *ifp, struct rtentry *rt, struct mbuf *m, 715 const struct sockaddr *dst, u_char *desten) 716 { 717 struct llinfo_arp *la; 718 const struct sockaddr_dl *sdl; 719 struct mbuf *mold; 720 int s; 721 722 if ((la = arplookup1(m, &satocsin(dst)->sin_addr, 1, 0, rt)) != NULL) 723 rt = la->la_rt; 724 725 if (la == 0 || rt == 0) { 726 arpstat.as_allocfail++; 727 log(LOG_DEBUG, 728 "arpresolve: can't allocate llinfo on %s for %s\n", 729 ifp->if_xname, in_fmtaddr(satocsin(dst)->sin_addr)); 730 m_freem(m); 731 return (0); 732 } 733 sdl = satocsdl(rt->rt_gateway); 734 /* 735 * Check the address family and length is valid, the address 736 * is resolved; otherwise, try to resolve. 737 */ 738 if ((rt->rt_expire == 0 || rt->rt_expire > time_second) && 739 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 740 bcopy(CLLADDR(sdl), desten, 741 min(sdl->sdl_alen, ifp->if_addrlen)); 742 rt->rt_pksent = time_second; /* Time for last pkt sent */ 743 return 1; 744 } 745 /* 746 * There is an arptab entry, but no ethernet address 747 * response yet. Replace the held mbuf with this 748 * latest one. 749 */ 750 751 arpstat.as_dfrtotal++; 752 s = splnet(); 753 mold = la->la_hold; 754 la->la_hold = m; 755 splx(s); 756 757 if (mold) { 758 arpstat.as_dfrdropped++; 759 m_freem(mold); 760 } 761 762 /* 763 * Re-send the ARP request when appropriate. 764 */ 765 #ifdef DIAGNOSTIC 766 if (rt->rt_expire == 0) { 767 /* This should never happen. (Should it? -gwr) */ 768 printf("arpresolve: unresolved and rt_expire == 0\n"); 769 /* Set expiration time to now (expired). */ 770 rt->rt_expire = time_second; 771 } 772 #endif 773 if (rt->rt_expire) { 774 rt->rt_flags &= ~RTF_REJECT; 775 if (la->la_asked == 0 || rt->rt_expire != time_second) { 776 rt->rt_expire = time_second; 777 if (la->la_asked++ < arp_maxtries) 778 arprequest(ifp, 779 &satocsin(rt->rt_ifa->ifa_addr)->sin_addr, 780 &satocsin(dst)->sin_addr, 781 #if NCARP > 0 782 (rt->rt_ifp->if_type == IFT_CARP) ? 783 CLLADDR(rt->rt_ifp->if_sadl): 784 #endif 785 CLLADDR(ifp->if_sadl)); 786 else { 787 rt->rt_flags |= RTF_REJECT; 788 rt->rt_expire += arpt_down; 789 la->la_asked = 0; 790 } 791 } 792 } 793 return (0); 794 } 795 796 /* 797 * Common length and type checks are done here, 798 * then the protocol-specific routine is called. 799 */ 800 void 801 arpintr(void) 802 { 803 struct mbuf *m; 804 struct arphdr *ar; 805 int s; 806 int arplen; 807 808 while (arpintrq.ifq_head) { 809 s = splnet(); 810 IF_DEQUEUE(&arpintrq, m); 811 splx(s); 812 if (m == 0 || (m->m_flags & M_PKTHDR) == 0) 813 panic("arpintr"); 814 815 MCLAIM(m, &arpdomain.dom_mowner); 816 arpstat.as_rcvtotal++; 817 818 /* 819 * First, make sure we have at least struct arphdr. 820 */ 821 if (m->m_len < sizeof(struct arphdr) || 822 (ar = mtod(m, struct arphdr *)) == NULL) 823 goto badlen; 824 825 switch (m->m_pkthdr.rcvif->if_type) { 826 case IFT_IEEE1394: 827 arplen = sizeof(struct arphdr) + 828 ar->ar_hln + 2 * ar->ar_pln; 829 break; 830 default: 831 arplen = sizeof(struct arphdr) + 832 2 * ar->ar_hln + 2 * ar->ar_pln; 833 break; 834 } 835 836 if (/* XXX ntohs(ar->ar_hrd) == ARPHRD_ETHER && */ 837 m->m_len >= arplen) 838 switch (ntohs(ar->ar_pro)) { 839 case ETHERTYPE_IP: 840 case ETHERTYPE_IPTRAILERS: 841 in_arpinput(m); 842 continue; 843 default: 844 arpstat.as_rcvbadproto++; 845 } 846 else { 847 badlen: 848 arpstat.as_rcvbadlen++; 849 } 850 m_freem(m); 851 } 852 } 853 854 /* 855 * ARP for Internet protocols on 10 Mb/s Ethernet. 856 * Algorithm is that given in RFC 826. 857 * In addition, a sanity check is performed on the sender 858 * protocol address, to catch impersonators. 859 * We no longer handle negotiations for use of trailer protocol: 860 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 861 * along with IP replies if we wanted trailers sent to us, 862 * and also sent them in response to IP replies. 863 * This allowed either end to announce the desire to receive 864 * trailer packets. 865 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 866 * but formerly didn't normally send requests. 867 */ 868 static void 869 in_arpinput(struct mbuf *m) 870 { 871 struct arphdr *ah; 872 struct ifnet *ifp = m->m_pkthdr.rcvif; 873 struct llinfo_arp *la = 0; 874 struct rtentry *rt; 875 struct in_ifaddr *ia; 876 #if NBRIDGE > 0 877 struct in_ifaddr *bridge_ia = NULL; 878 #endif 879 #if NCARP > 0 880 u_int32_t count = 0, index = 0; 881 #endif 882 struct sockaddr_dl *sdl; 883 struct sockaddr sa; 884 struct in_addr isaddr, itaddr, myaddr; 885 int op; 886 struct mbuf *mold; 887 void *tha; 888 int s; 889 890 if (__predict_false(m_makewritable(&m, 0, m->m_pkthdr.len, M_DONTWAIT))) 891 goto out; 892 ah = mtod(m, struct arphdr *); 893 op = ntohs(ah->ar_op); 894 895 /* 896 * Fix up ah->ar_hrd if necessary, before using ar_tha() or 897 * ar_tpa(). 898 */ 899 switch (ifp->if_type) { 900 case IFT_IEEE1394: 901 if (ntohs(ah->ar_hrd) == ARPHRD_IEEE1394) 902 ; 903 else { 904 /* XXX this is to make sure we compute ar_tha right */ 905 /* XXX check ar_hrd more strictly? */ 906 ah->ar_hrd = htons(ARPHRD_IEEE1394); 907 } 908 break; 909 default: 910 /* XXX check ar_hrd? */ 911 break; 912 } 913 914 memcpy(&isaddr, ar_spa(ah), sizeof (isaddr)); 915 memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr)); 916 917 if (m->m_flags & (M_BCAST|M_MCAST)) 918 arpstat.as_rcvmcast++; 919 920 /* 921 * If the target IP address is zero, ignore the packet. 922 * This prevents the code below from tring to answer 923 * when we are using IP address zero (booting). 924 */ 925 if (in_nullhost(itaddr)) { 926 arpstat.as_rcvzerotpa++; 927 goto out; 928 } 929 930 /* 931 * If the source IP address is zero, this is most likely a 932 * confused host trying to use IP address zero. (Windoze?) 933 * XXX: Should we bother trying to reply to these? 934 */ 935 if (in_nullhost(isaddr)) { 936 arpstat.as_rcvzerospa++; 937 goto out; 938 } 939 940 /* 941 * Search for a matching interface address 942 * or any address on the interface to use 943 * as a dummy address in the rest of this function 944 */ 945 946 INADDR_TO_IA(itaddr, ia); 947 while (ia != NULL) { 948 #if NCARP > 0 949 if (ia->ia_ifp->if_type == IFT_CARP && 950 ((ia->ia_ifp->if_flags & (IFF_UP|IFF_RUNNING)) == 951 (IFF_UP|IFF_RUNNING))) { 952 index++; 953 if (ia->ia_ifp == m->m_pkthdr.rcvif && 954 carp_iamatch(ia, ar_sha(ah), 955 &count, index)) { 956 break; 957 } 958 } else 959 #endif 960 if (ia->ia_ifp == m->m_pkthdr.rcvif) 961 break; 962 #if NBRIDGE > 0 963 /* 964 * If the interface we received the packet on 965 * is part of a bridge, check to see if we need 966 * to "bridge" the packet to ourselves at this 967 * layer. Note we still prefer a perfect match, 968 * but allow this weaker match if necessary. 969 */ 970 if (m->m_pkthdr.rcvif->if_bridge != NULL && 971 m->m_pkthdr.rcvif->if_bridge == ia->ia_ifp->if_bridge) 972 bridge_ia = ia; 973 #endif /* NBRIDGE > 0 */ 974 975 NEXT_IA_WITH_SAME_ADDR(ia); 976 } 977 978 #if NBRIDGE > 0 979 if (ia == NULL && bridge_ia != NULL) { 980 ia = bridge_ia; 981 ifp = bridge_ia->ia_ifp; 982 } 983 #endif 984 985 if (ia == NULL) { 986 INADDR_TO_IA(isaddr, ia); 987 while ((ia != NULL) && ia->ia_ifp != m->m_pkthdr.rcvif) 988 NEXT_IA_WITH_SAME_ADDR(ia); 989 990 if (ia == NULL) { 991 IFP_TO_IA(ifp, ia); 992 if (ia == NULL) { 993 arpstat.as_rcvnoint++; 994 goto out; 995 } 996 } 997 } 998 999 myaddr = ia->ia_addr.sin_addr; 1000 1001 /* XXX checks for bridge case? */ 1002 if (!memcmp(ar_sha(ah), CLLADDR(ifp->if_sadl), ifp->if_addrlen)) { 1003 arpstat.as_rcvlocalsha++; 1004 goto out; /* it's from me, ignore it. */ 1005 } 1006 1007 /* XXX checks for bridge case? */ 1008 if (!memcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) { 1009 arpstat.as_rcvbcastsha++; 1010 log(LOG_ERR, 1011 "%s: arp: link address is broadcast for IP address %s!\n", 1012 ifp->if_xname, in_fmtaddr(isaddr)); 1013 goto out; 1014 } 1015 1016 if (in_hosteq(isaddr, myaddr)) { 1017 arpstat.as_rcvlocalspa++; 1018 log(LOG_ERR, 1019 "duplicate IP address %s sent from link address %s\n", 1020 in_fmtaddr(isaddr), lla_snprintf(ar_sha(ah), ah->ar_hln)); 1021 itaddr = myaddr; 1022 goto reply; 1023 } 1024 la = arplookup(m, &isaddr, in_hosteq(itaddr, myaddr), 0); 1025 if (la && (rt = la->la_rt) && (sdl = satosdl(rt->rt_gateway))) { 1026 if (sdl->sdl_alen && 1027 memcmp(ar_sha(ah), CLLADDR(sdl), sdl->sdl_alen)) { 1028 if (rt->rt_flags & RTF_STATIC) { 1029 arpstat.as_rcvoverperm++; 1030 log(LOG_INFO, 1031 "%s tried to overwrite permanent arp info" 1032 " for %s\n", 1033 lla_snprintf(ar_sha(ah), ah->ar_hln), 1034 in_fmtaddr(isaddr)); 1035 goto out; 1036 } else if (rt->rt_ifp != ifp) { 1037 arpstat.as_rcvoverint++; 1038 log(LOG_INFO, 1039 "%s on %s tried to overwrite " 1040 "arp info for %s on %s\n", 1041 lla_snprintf(ar_sha(ah), ah->ar_hln), 1042 ifp->if_xname, in_fmtaddr(isaddr), 1043 rt->rt_ifp->if_xname); 1044 goto out; 1045 } else { 1046 arpstat.as_rcvover++; 1047 log(LOG_INFO, 1048 "arp info overwritten for %s by %s\n", 1049 in_fmtaddr(isaddr), 1050 lla_snprintf(ar_sha(ah), ah->ar_hln)); 1051 } 1052 } 1053 /* 1054 * sanity check for the address length. 1055 * XXX this does not work for protocols with variable address 1056 * length. -is 1057 */ 1058 if (sdl->sdl_alen && 1059 sdl->sdl_alen != ah->ar_hln) { 1060 arpstat.as_rcvlenchg++; 1061 log(LOG_WARNING, 1062 "arp from %s: new addr len %d, was %d", 1063 in_fmtaddr(isaddr), ah->ar_hln, sdl->sdl_alen); 1064 } 1065 if (ifp->if_addrlen != ah->ar_hln) { 1066 arpstat.as_rcvbadlen++; 1067 log(LOG_WARNING, 1068 "arp from %s: addr len: new %d, i/f %d (ignored)", 1069 in_fmtaddr(isaddr), ah->ar_hln, 1070 ifp->if_addrlen); 1071 goto reply; 1072 } 1073 #if NTOKEN > 0 1074 /* 1075 * XXX uses m_data and assumes the complete answer including 1076 * XXX token-ring headers is in the same buf 1077 */ 1078 if (ifp->if_type == IFT_ISO88025) { 1079 struct token_header *trh; 1080 1081 trh = (struct token_header *)M_TRHSTART(m); 1082 if (trh->token_shost[0] & TOKEN_RI_PRESENT) { 1083 struct token_rif *rif; 1084 size_t riflen; 1085 1086 rif = TOKEN_RIF(trh); 1087 riflen = (ntohs(rif->tr_rcf) & 1088 TOKEN_RCF_LEN_MASK) >> 8; 1089 1090 if (riflen > 2 && 1091 riflen < sizeof(struct token_rif) && 1092 (riflen & 1) == 0) { 1093 rif->tr_rcf ^= htons(TOKEN_RCF_DIRECTION); 1094 rif->tr_rcf &= htons(~TOKEN_RCF_BROADCAST_MASK); 1095 bcopy(rif, TOKEN_RIF(la), riflen); 1096 } 1097 } 1098 } 1099 #endif /* NTOKEN > 0 */ 1100 (void)sockaddr_dl_setaddr(sdl, sdl->sdl_len, ar_sha(ah), 1101 ah->ar_hln); 1102 if (rt->rt_expire) 1103 rt->rt_expire = time_second + arpt_keep; 1104 rt->rt_flags &= ~RTF_REJECT; 1105 la->la_asked = 0; 1106 1107 s = splnet(); 1108 mold = la->la_hold; 1109 la->la_hold = 0; 1110 splx(s); 1111 1112 if (mold) { 1113 arpstat.as_dfrsent++; 1114 (*ifp->if_output)(ifp, mold, rt_getkey(rt), rt); 1115 } 1116 } 1117 reply: 1118 if (op != ARPOP_REQUEST) { 1119 if (op == ARPOP_REPLY) 1120 arpstat.as_rcvreply++; 1121 out: 1122 m_freem(m); 1123 return; 1124 } 1125 arpstat.as_rcvrequest++; 1126 if (in_hosteq(itaddr, myaddr)) { 1127 /* I am the target */ 1128 tha = ar_tha(ah); 1129 if (tha) 1130 memcpy(tha, ar_sha(ah), ah->ar_hln); 1131 memcpy(ar_sha(ah), CLLADDR(ifp->if_sadl), ah->ar_hln); 1132 } else { 1133 la = arplookup(m, &itaddr, 0, SIN_PROXY); 1134 if (la == 0) 1135 goto out; 1136 rt = la->la_rt; 1137 if (rt->rt_ifp->if_type == IFT_CARP && 1138 m->m_pkthdr.rcvif->if_type != IFT_CARP) 1139 goto out; 1140 tha = ar_tha(ah); 1141 if (tha) 1142 memcpy(tha, ar_sha(ah), ah->ar_hln); 1143 sdl = satosdl(rt->rt_gateway); 1144 memcpy(ar_sha(ah), CLLADDR(sdl), ah->ar_hln); 1145 } 1146 1147 memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln); 1148 memcpy(ar_spa(ah), &itaddr, ah->ar_pln); 1149 ah->ar_op = htons(ARPOP_REPLY); 1150 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 1151 switch (ifp->if_type) { 1152 case IFT_IEEE1394: 1153 /* 1154 * ieee1394 arp reply is broadcast 1155 */ 1156 m->m_flags &= ~M_MCAST; 1157 m->m_flags |= M_BCAST; 1158 m->m_len = sizeof(*ah) + (2 * ah->ar_pln) + ah->ar_hln; 1159 break; 1160 1161 default: 1162 m->m_flags &= ~(M_BCAST|M_MCAST); /* never reply by broadcast */ 1163 m->m_len = sizeof(*ah) + (2 * ah->ar_pln) + (2 * ah->ar_hln); 1164 break; 1165 } 1166 m->m_pkthdr.len = m->m_len; 1167 sa.sa_family = AF_ARP; 1168 sa.sa_len = 2; 1169 arpstat.as_sndtotal++; 1170 arpstat.as_sndreply++; 1171 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 1172 return; 1173 } 1174 1175 /* 1176 * Free an arp entry. 1177 */ 1178 static void arptfree(struct llinfo_arp *la) 1179 { 1180 struct rtentry *rt = la->la_rt; 1181 struct sockaddr_dl *sdl; 1182 1183 ARP_LOCK_CHECK(); 1184 1185 if (rt == 0) 1186 panic("arptfree"); 1187 if (rt->rt_refcnt > 0 && (sdl = satosdl(rt->rt_gateway)) && 1188 sdl->sdl_family == AF_LINK) { 1189 sdl->sdl_alen = 0; 1190 la->la_asked = 0; 1191 rt->rt_flags &= ~RTF_REJECT; 1192 return; 1193 } 1194 rtrequest(RTM_DELETE, rt_getkey(rt), NULL, rt_mask(rt), 0, NULL); 1195 } 1196 1197 static struct llinfo_arp * 1198 arplookup(struct mbuf *m, const struct in_addr *addr, int create, int proxy) 1199 { 1200 return arplookup1(m, addr, create, proxy, NULL); 1201 } 1202 1203 /* 1204 * Lookup or enter a new address in arptab. 1205 */ 1206 static struct llinfo_arp * 1207 arplookup1(struct mbuf *m, const struct in_addr *addr, int create, int proxy, 1208 struct rtentry *rt0) 1209 { 1210 struct arphdr *ah; 1211 struct ifnet *ifp = m->m_pkthdr.rcvif; 1212 struct rtentry *rt; 1213 static struct sockaddr_inarp sin; 1214 const char *why = 0; 1215 1216 ah = mtod(m, struct arphdr *); 1217 if (rt0 == NULL) { 1218 sin.sin_len = sizeof(sin); 1219 sin.sin_family = AF_INET; 1220 sin.sin_addr = *addr; 1221 sin.sin_other = proxy ? SIN_PROXY : 0; 1222 rt = rtalloc1(sintosa(&sin), create); 1223 if (rt == NULL) 1224 return (NULL); 1225 rt->rt_refcnt--; 1226 } else 1227 rt = rt0; 1228 1229 #define IS_LLINFO(__rt) \ 1230 (((__rt)->rt_flags & (RTF_GATEWAY | RTF_LLINFO)) == RTF_LLINFO && \ 1231 (__rt)->rt_gateway->sa_family == AF_LINK) 1232 1233 1234 if (IS_LLINFO(rt)) 1235 return ((struct llinfo_arp *)rt->rt_llinfo); 1236 1237 if (create) { 1238 if (rt->rt_flags & RTF_GATEWAY) 1239 why = "host is not on local network"; 1240 else if ((rt->rt_flags & RTF_LLINFO) == 0) { 1241 arpstat.as_allocfail++; 1242 why = "could not allocate llinfo"; 1243 } else 1244 why = "gateway route is not ours"; 1245 log(LOG_DEBUG, "arplookup: unable to enter address" 1246 " for %s@%s on %s (%s)\n", 1247 in_fmtaddr(*addr), lla_snprintf(ar_sha(ah), ah->ar_hln), 1248 (ifp) ? ifp->if_xname : 0, why); 1249 if (rt->rt_refcnt <= 0 && (rt->rt_flags & RTF_CLONED) != 0) { 1250 rtrequest(RTM_DELETE, rt_getkey(rt), 1251 rt->rt_gateway, rt_mask(rt), rt->rt_flags, 0); 1252 } 1253 } 1254 return (0); 1255 } 1256 1257 int 1258 arpioctl(u_long cmd, void *data) 1259 { 1260 1261 return (EOPNOTSUPP); 1262 } 1263 1264 void 1265 arp_ifinit(struct ifnet *ifp, struct ifaddr *ifa) 1266 { 1267 struct in_addr *ip; 1268 1269 /* 1270 * Warn the user if another station has this IP address, 1271 * but only if the interface IP address is not zero. 1272 */ 1273 ip = &IA_SIN(ifa)->sin_addr; 1274 if (!in_nullhost(*ip)) 1275 arprequest(ifp, ip, ip, CLLADDR(ifp->if_sadl)); 1276 1277 ifa->ifa_rtrequest = arp_rtrequest; 1278 ifa->ifa_flags |= RTF_CLONING; 1279 } 1280 1281 /* 1282 * Called from 10 Mb/s Ethernet interrupt handlers 1283 * when ether packet type ETHERTYPE_REVARP 1284 * is received. Common length and type checks are done here, 1285 * then the protocol-specific routine is called. 1286 */ 1287 void 1288 revarpinput(struct mbuf *m) 1289 { 1290 struct arphdr *ar; 1291 1292 if (m->m_len < sizeof(struct arphdr)) 1293 goto out; 1294 ar = mtod(m, struct arphdr *); 1295 #if 0 /* XXX I don't think we need this... and it will prevent other LL */ 1296 if (ntohs(ar->ar_hrd) != ARPHRD_ETHER) 1297 goto out; 1298 #endif 1299 if (m->m_len < sizeof(struct arphdr) + 2 * (ar->ar_hln + ar->ar_pln)) 1300 goto out; 1301 switch (ntohs(ar->ar_pro)) { 1302 case ETHERTYPE_IP: 1303 case ETHERTYPE_IPTRAILERS: 1304 in_revarpinput(m); 1305 return; 1306 1307 default: 1308 break; 1309 } 1310 out: 1311 m_freem(m); 1312 } 1313 1314 /* 1315 * RARP for Internet protocols on 10 Mb/s Ethernet. 1316 * Algorithm is that given in RFC 903. 1317 * We are only using for bootstrap purposes to get an ip address for one of 1318 * our interfaces. Thus we support no user-interface. 1319 * 1320 * Since the contents of the RARP reply are specific to the interface that 1321 * sent the request, this code must ensure that they are properly associated. 1322 * 1323 * Note: also supports ARP via RARP packets, per the RFC. 1324 */ 1325 void 1326 in_revarpinput(struct mbuf *m) 1327 { 1328 struct ifnet *ifp; 1329 struct arphdr *ah; 1330 void *tha; 1331 int op; 1332 1333 ah = mtod(m, struct arphdr *); 1334 op = ntohs(ah->ar_op); 1335 1336 switch (m->m_pkthdr.rcvif->if_type) { 1337 case IFT_IEEE1394: 1338 /* ARP without target hardware address is not supported */ 1339 goto out; 1340 default: 1341 break; 1342 } 1343 1344 switch (op) { 1345 case ARPOP_REQUEST: 1346 case ARPOP_REPLY: /* per RFC */ 1347 in_arpinput(m); 1348 return; 1349 case ARPOP_REVREPLY: 1350 break; 1351 case ARPOP_REVREQUEST: /* handled by rarpd(8) */ 1352 default: 1353 goto out; 1354 } 1355 if (!revarp_in_progress) 1356 goto out; 1357 ifp = m->m_pkthdr.rcvif; 1358 if (ifp != myip_ifp) /* !same interface */ 1359 goto out; 1360 if (myip_initialized) 1361 goto wake; 1362 tha = ar_tha(ah); 1363 KASSERT(tha); 1364 if (bcmp(tha, CLLADDR(ifp->if_sadl), ifp->if_sadl->sdl_alen)) 1365 goto out; 1366 memcpy(&srv_ip, ar_spa(ah), sizeof(srv_ip)); 1367 memcpy(&myip, ar_tpa(ah), sizeof(myip)); 1368 myip_initialized = 1; 1369 wake: /* Do wakeup every time in case it was missed. */ 1370 wakeup((void *)&myip); 1371 1372 out: 1373 m_freem(m); 1374 } 1375 1376 /* 1377 * Send a RARP request for the ip address of the specified interface. 1378 * The request should be RFC 903-compliant. 1379 */ 1380 void 1381 revarprequest(struct ifnet *ifp) 1382 { 1383 struct sockaddr sa; 1384 struct mbuf *m; 1385 struct arphdr *ah; 1386 void *tha; 1387 1388 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 1389 return; 1390 MCLAIM(m, &arpdomain.dom_mowner); 1391 m->m_len = sizeof(*ah) + 2*sizeof(struct in_addr) + 1392 2*ifp->if_addrlen; 1393 m->m_pkthdr.len = m->m_len; 1394 MH_ALIGN(m, m->m_len); 1395 ah = mtod(m, struct arphdr *); 1396 bzero((void *)ah, m->m_len); 1397 ah->ar_pro = htons(ETHERTYPE_IP); 1398 ah->ar_hln = ifp->if_addrlen; /* hardware address length */ 1399 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 1400 ah->ar_op = htons(ARPOP_REVREQUEST); 1401 1402 memcpy(ar_sha(ah), CLLADDR(ifp->if_sadl), ah->ar_hln); 1403 tha = ar_tha(ah); 1404 KASSERT(tha); 1405 bcopy(CLLADDR(ifp->if_sadl), tha, ah->ar_hln); 1406 1407 sa.sa_family = AF_ARP; 1408 sa.sa_len = 2; 1409 m->m_flags |= M_BCAST; 1410 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 1411 1412 } 1413 1414 /* 1415 * RARP for the ip address of the specified interface, but also 1416 * save the ip address of the server that sent the answer. 1417 * Timeout if no response is received. 1418 */ 1419 int 1420 revarpwhoarewe(struct ifnet *ifp, struct in_addr *serv_in, 1421 struct in_addr *clnt_in) 1422 { 1423 int result, count = 20; 1424 1425 myip_initialized = 0; 1426 myip_ifp = ifp; 1427 1428 revarp_in_progress = 1; 1429 while (count--) { 1430 revarprequest(ifp); 1431 result = tsleep((void *)&myip, PSOCK, "revarp", hz/2); 1432 if (result != EWOULDBLOCK) 1433 break; 1434 } 1435 revarp_in_progress = 0; 1436 1437 if (!myip_initialized) 1438 return ENETUNREACH; 1439 1440 bcopy((void *)&srv_ip, serv_in, sizeof(*serv_in)); 1441 bcopy((void *)&myip, clnt_in, sizeof(*clnt_in)); 1442 return 0; 1443 } 1444 1445 1446 1447 #ifdef DDB 1448 1449 #include <machine/db_machdep.h> 1450 #include <ddb/db_interface.h> 1451 #include <ddb/db_output.h> 1452 1453 static void 1454 db_print_sa(const struct sockaddr *sa) 1455 { 1456 int len; 1457 const u_char *p; 1458 1459 if (sa == 0) { 1460 db_printf("[NULL]"); 1461 return; 1462 } 1463 1464 p = (const u_char *)sa; 1465 len = sa->sa_len; 1466 db_printf("["); 1467 while (len > 0) { 1468 db_printf("%d", *p); 1469 p++; len--; 1470 if (len) db_printf(","); 1471 } 1472 db_printf("]\n"); 1473 } 1474 1475 static void 1476 db_print_ifa(struct ifaddr *ifa) 1477 { 1478 if (ifa == 0) 1479 return; 1480 db_printf(" ifa_addr="); 1481 db_print_sa(ifa->ifa_addr); 1482 db_printf(" ifa_dsta="); 1483 db_print_sa(ifa->ifa_dstaddr); 1484 db_printf(" ifa_mask="); 1485 db_print_sa(ifa->ifa_netmask); 1486 db_printf(" flags=0x%x,refcnt=%d,metric=%d\n", 1487 ifa->ifa_flags, 1488 ifa->ifa_refcnt, 1489 ifa->ifa_metric); 1490 } 1491 1492 static void 1493 db_print_llinfo(void *li) 1494 { 1495 struct llinfo_arp *la; 1496 1497 if (li == 0) 1498 return; 1499 la = (struct llinfo_arp *)li; 1500 db_printf(" la_rt=%p la_hold=%p, la_asked=0x%lx\n", 1501 la->la_rt, la->la_hold, la->la_asked); 1502 } 1503 1504 /* 1505 * Function to pass to rt_walktree(). 1506 * Return non-zero error to abort walk. 1507 */ 1508 static int 1509 db_show_rtentry(struct rtentry *rt, void *w) 1510 { 1511 db_printf("rtentry=%p", rt); 1512 1513 db_printf(" flags=0x%x refcnt=%d use=%ld expire=%ld\n", 1514 rt->rt_flags, rt->rt_refcnt, 1515 rt->rt_use, rt->rt_expire); 1516 1517 db_printf(" key="); db_print_sa(rt_getkey(rt)); 1518 db_printf(" mask="); db_print_sa(rt_mask(rt)); 1519 db_printf(" gw="); db_print_sa(rt->rt_gateway); 1520 1521 db_printf(" ifp=%p ", rt->rt_ifp); 1522 if (rt->rt_ifp) 1523 db_printf("(%s)", rt->rt_ifp->if_xname); 1524 else 1525 db_printf("(NULL)"); 1526 1527 db_printf(" ifa=%p\n", rt->rt_ifa); 1528 db_print_ifa(rt->rt_ifa); 1529 1530 db_printf(" gwroute=%p llinfo=%p\n", 1531 rt->rt_gwroute, rt->rt_llinfo); 1532 db_print_llinfo(rt->rt_llinfo); 1533 1534 return (0); 1535 } 1536 1537 /* 1538 * Function to print all the route trees. 1539 * Use this from ddb: "show arptab" 1540 */ 1541 void 1542 db_show_arptab(db_expr_t addr, bool have_addr, 1543 db_expr_t count, const char *modif) 1544 { 1545 rt_walktree(AF_INET, db_show_rtentry, NULL); 1546 } 1547 #endif 1548 1549 SYSCTL_SETUP(sysctl_net_inet_arp_setup, "sysctl net.inet.arp subtree setup") 1550 { 1551 const struct sysctlnode *node; 1552 1553 sysctl_createv(clog, 0, NULL, NULL, 1554 CTLFLAG_PERMANENT, 1555 CTLTYPE_NODE, "net", NULL, 1556 NULL, 0, NULL, 0, 1557 CTL_NET, CTL_EOL); 1558 sysctl_createv(clog, 0, NULL, NULL, 1559 CTLFLAG_PERMANENT, 1560 CTLTYPE_NODE, "inet", NULL, 1561 NULL, 0, NULL, 0, 1562 CTL_NET, PF_INET, CTL_EOL); 1563 sysctl_createv(clog, 0, NULL, &node, 1564 CTLFLAG_PERMANENT, 1565 CTLTYPE_NODE, "arp", 1566 SYSCTL_DESCR("Address Resolution Protocol"), 1567 NULL, 0, NULL, 0, 1568 CTL_NET, PF_INET, CTL_CREATE, CTL_EOL); 1569 1570 sysctl_createv(clog, 0, NULL, NULL, 1571 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1572 CTLTYPE_INT, "prune", 1573 SYSCTL_DESCR("ARP cache pruning interval"), 1574 NULL, 0, &arpt_prune, 0, 1575 CTL_NET,PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL); 1576 1577 sysctl_createv(clog, 0, NULL, NULL, 1578 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1579 CTLTYPE_INT, "keep", 1580 SYSCTL_DESCR("Valid ARP entry lifetime"), 1581 NULL, 0, &arpt_keep, 0, 1582 CTL_NET,PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL); 1583 1584 sysctl_createv(clog, 0, NULL, NULL, 1585 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1586 CTLTYPE_INT, "down", 1587 SYSCTL_DESCR("Failed ARP entry lifetime"), 1588 NULL, 0, &arpt_down, 0, 1589 CTL_NET,PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL); 1590 1591 sysctl_createv(clog, 0, NULL, NULL, 1592 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1593 CTLTYPE_INT, "refresh", 1594 SYSCTL_DESCR("ARP entry refresh interval"), 1595 NULL, 0, &arpt_refresh, 0, 1596 CTL_NET,PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL); 1597 } 1598 1599 #endif /* INET */ 1600