1 /* $NetBSD: if_arp.c,v 1.130 2007/12/07 19:46:18 elad 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 1.130 2007/12/07 19:46:18 elad 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 #ifdef __HAVE_TIMECOUNTER 458 struct timespec ts; 459 ts.tv_sec = 1; 460 ts.tv_nsec = 0; 461 tc_setclock(&ts); 462 #else /* !__HAVE_TIMECOUNTER */ 463 time.tv_sec++; 464 #endif /* !__HAVE_TIMECOUNTER */ 465 } 466 callout_init(&arptimer_ch, 0); 467 callout_reset(&arptimer_ch, hz, arptimer, NULL); 468 } 469 470 if ((rt->rt_flags & RTF_GATEWAY) != 0) { 471 if (req != RTM_ADD) 472 return; 473 474 /* 475 * linklayers with particular link MTU limitation. 476 */ 477 switch(ifp->if_type) { 478 #if NFDDI > 0 479 case IFT_FDDI: 480 if (ifp->if_mtu > FDDIIPMTU) 481 rt->rt_rmx.rmx_mtu = FDDIIPMTU; 482 break; 483 #endif 484 #if NARC > 0 485 case IFT_ARCNET: 486 { 487 int arcipifmtu; 488 489 if (ifp->if_flags & IFF_LINK0) 490 arcipifmtu = arc_ipmtu; 491 else 492 arcipifmtu = ARCMTU; 493 if (ifp->if_mtu > arcipifmtu) 494 rt->rt_rmx.rmx_mtu = arcipifmtu; 495 break; 496 } 497 #endif 498 } 499 return; 500 } 501 502 ARP_LOCK(1); /* we may already be locked here. */ 503 504 switch (req) { 505 506 case RTM_SETGATE: 507 gate = arp_setgate(rt, gate, info->rti_info[RTAX_NETMASK]); 508 break; 509 case RTM_ADD: 510 gate = arp_setgate(rt, gate, info->rti_info[RTAX_NETMASK]); 511 if (rt->rt_flags & RTF_CLONING) { 512 /* 513 * Give this route an expiration time, even though 514 * it's a "permanent" route, so that routes cloned 515 * from it do not need their expiration time set. 516 */ 517 rt->rt_expire = time_second; 518 /* 519 * linklayers with particular link MTU limitation. 520 */ 521 switch (ifp->if_type) { 522 #if NFDDI > 0 523 case IFT_FDDI: 524 if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0 && 525 (rt->rt_rmx.rmx_mtu > FDDIIPMTU || 526 (rt->rt_rmx.rmx_mtu == 0 && 527 ifp->if_mtu > FDDIIPMTU))) 528 rt->rt_rmx.rmx_mtu = FDDIIPMTU; 529 break; 530 #endif 531 #if NARC > 0 532 case IFT_ARCNET: 533 { 534 int arcipifmtu; 535 if (ifp->if_flags & IFF_LINK0) 536 arcipifmtu = arc_ipmtu; 537 else 538 arcipifmtu = ARCMTU; 539 540 if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0 && 541 (rt->rt_rmx.rmx_mtu > arcipifmtu || 542 (rt->rt_rmx.rmx_mtu == 0 && 543 ifp->if_mtu > arcipifmtu))) 544 rt->rt_rmx.rmx_mtu = arcipifmtu; 545 break; 546 } 547 #endif 548 } 549 break; 550 } 551 /* Announce a new entry if requested. */ 552 if (rt->rt_flags & RTF_ANNOUNCE) 553 arprequest(ifp, 554 &satocsin(rt_getkey(rt))->sin_addr, 555 &satocsin(rt_getkey(rt))->sin_addr, 556 CLLADDR(satocsdl(gate))); 557 /*FALLTHROUGH*/ 558 case RTM_RESOLVE: 559 if (gate->sa_family != AF_LINK || 560 gate->sa_len < sockaddr_dl_measure(namelen, addrlen)) { 561 log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n"); 562 break; 563 } 564 satosdl(gate)->sdl_type = ifp->if_type; 565 satosdl(gate)->sdl_index = ifp->if_index; 566 if (la != 0) 567 break; /* This happens on a route change */ 568 /* 569 * Case 2: This route may come from cloning, or a manual route 570 * add with a LL address. 571 */ 572 switch (satocsdl(gate)->sdl_type) { 573 #if NTOKEN > 0 574 case IFT_ISO88025: 575 allocsize = sizeof(*la) + sizeof(struct token_rif); 576 break; 577 #endif /* NTOKEN > 0 */ 578 default: 579 allocsize = sizeof(*la); 580 } 581 R_Malloc(la, struct llinfo_arp *, allocsize); 582 rt->rt_llinfo = (void *)la; 583 if (la == 0) { 584 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); 585 break; 586 } 587 arp_inuse++, arp_allocated++; 588 Bzero(la, allocsize); 589 la->la_rt = rt; 590 rt->rt_flags |= RTF_LLINFO; 591 LIST_INSERT_HEAD(&llinfo_arp, la, la_list); 592 593 INADDR_TO_IA(satocsin(rt_getkey(rt))->sin_addr, ia); 594 while (ia && ia->ia_ifp != ifp) 595 NEXT_IA_WITH_SAME_ADDR(ia); 596 if (ia) { 597 /* 598 * This test used to be 599 * if (lo0ifp->if_flags & IFF_UP) 600 * It allowed local traffic to be forced through 601 * the hardware by configuring the loopback down. 602 * However, it causes problems during network 603 * configuration for boards that can't receive 604 * packets they send. It is now necessary to clear 605 * "useloopback" and remove the route to force 606 * traffic out to the hardware. 607 * 608 * In 4.4BSD, the above "if" statement checked 609 * rt->rt_ifa against rt_getkey(rt). It was changed 610 * to the current form so that we can provide a 611 * better support for multiple IPv4 addresses on a 612 * interface. 613 */ 614 rt->rt_expire = 0; 615 (void)sockaddr_dl_setaddr(satosdl(gate), gate->sa_len, 616 CLLADDR(ifp->if_sadl), ifp->if_addrlen); 617 if (useloopback) 618 ifp = rt->rt_ifp = lo0ifp; 619 /* 620 * make sure to set rt->rt_ifa to the interface 621 * address we are using, otherwise we will have trouble 622 * with source address selection. 623 */ 624 ifa = &ia->ia_ifa; 625 if (ifa != rt->rt_ifa) 626 rt_replace_ifa(rt, ifa); 627 } 628 break; 629 630 case RTM_DELETE: 631 if (la == 0) 632 break; 633 arp_inuse--; 634 LIST_REMOVE(la, la_list); 635 rt->rt_llinfo = 0; 636 rt->rt_flags &= ~RTF_LLINFO; 637 638 s = splnet(); 639 mold = la->la_hold; 640 la->la_hold = 0; 641 splx(s); 642 643 if (mold) 644 m_freem(mold); 645 646 Free((void *)la); 647 } 648 ARP_UNLOCK(); 649 } 650 651 /* 652 * Broadcast an ARP request. Caller specifies: 653 * - arp header source ip address 654 * - arp header target ip address 655 * - arp header source ethernet address 656 */ 657 void 658 arprequest(struct ifnet *ifp, 659 const struct in_addr *sip, const struct in_addr *tip, 660 const u_int8_t *enaddr) 661 { 662 struct mbuf *m; 663 struct arphdr *ah; 664 struct sockaddr sa; 665 666 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 667 return; 668 MCLAIM(m, &arpdomain.dom_mowner); 669 switch (ifp->if_type) { 670 case IFT_IEEE1394: 671 m->m_len = sizeof(*ah) + 2 * sizeof(struct in_addr) + 672 ifp->if_addrlen; 673 break; 674 default: 675 m->m_len = sizeof(*ah) + 2 * sizeof(struct in_addr) + 676 2 * ifp->if_addrlen; 677 break; 678 } 679 m->m_pkthdr.len = m->m_len; 680 MH_ALIGN(m, m->m_len); 681 ah = mtod(m, struct arphdr *); 682 bzero((void *)ah, m->m_len); 683 switch (ifp->if_type) { 684 case IFT_IEEE1394: /* RFC2734 */ 685 /* fill it now for ar_tpa computation */ 686 ah->ar_hrd = htons(ARPHRD_IEEE1394); 687 break; 688 default: 689 /* ifp->if_output will fill ar_hrd */ 690 break; 691 } 692 ah->ar_pro = htons(ETHERTYPE_IP); 693 ah->ar_hln = ifp->if_addrlen; /* hardware address length */ 694 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 695 ah->ar_op = htons(ARPOP_REQUEST); 696 memcpy(ar_sha(ah), enaddr, ah->ar_hln); 697 memcpy(ar_spa(ah), sip, ah->ar_pln); 698 memcpy(ar_tpa(ah), tip, ah->ar_pln); 699 sa.sa_family = AF_ARP; 700 sa.sa_len = 2; 701 m->m_flags |= M_BCAST; 702 arpstat.as_sndtotal++; 703 arpstat.as_sndrequest++; 704 (*ifp->if_output)(ifp, m, &sa, NULL); 705 } 706 707 /* 708 * Resolve an IP address into an ethernet address. If success, 709 * desten is filled in. If there is no entry in arptab, 710 * set one up and broadcast a request for the IP address. 711 * Hold onto this mbuf and resend it once the address 712 * is finally resolved. A return value of 1 indicates 713 * that desten has been filled in and the packet should be sent 714 * normally; a 0 return indicates that the packet has been 715 * taken over here, either now or for later transmission. 716 */ 717 int 718 arpresolve(struct ifnet *ifp, struct rtentry *rt, struct mbuf *m, 719 const struct sockaddr *dst, u_char *desten) 720 { 721 struct llinfo_arp *la; 722 const struct sockaddr_dl *sdl; 723 struct mbuf *mold; 724 int s; 725 726 if ((la = arplookup1(m, &satocsin(dst)->sin_addr, 1, 0, rt)) != NULL) 727 rt = la->la_rt; 728 729 if (la == 0 || rt == 0) { 730 arpstat.as_allocfail++; 731 log(LOG_DEBUG, 732 "arpresolve: can't allocate llinfo on %s for %s\n", 733 ifp->if_xname, in_fmtaddr(satocsin(dst)->sin_addr)); 734 m_freem(m); 735 return (0); 736 } 737 sdl = satocsdl(rt->rt_gateway); 738 /* 739 * Check the address family and length is valid, the address 740 * is resolved; otherwise, try to resolve. 741 */ 742 if ((rt->rt_expire == 0 || rt->rt_expire > time_second) && 743 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 744 bcopy(CLLADDR(sdl), desten, 745 min(sdl->sdl_alen, ifp->if_addrlen)); 746 rt->rt_pksent = time_second; /* Time for last pkt sent */ 747 return 1; 748 } 749 /* 750 * There is an arptab entry, but no ethernet address 751 * response yet. Replace the held mbuf with this 752 * latest one. 753 */ 754 755 arpstat.as_dfrtotal++; 756 s = splnet(); 757 mold = la->la_hold; 758 la->la_hold = m; 759 splx(s); 760 761 if (mold) { 762 arpstat.as_dfrdropped++; 763 m_freem(mold); 764 } 765 766 /* 767 * Re-send the ARP request when appropriate. 768 */ 769 #ifdef DIAGNOSTIC 770 if (rt->rt_expire == 0) { 771 /* This should never happen. (Should it? -gwr) */ 772 printf("arpresolve: unresolved and rt_expire == 0\n"); 773 /* Set expiration time to now (expired). */ 774 rt->rt_expire = time_second; 775 } 776 #endif 777 if (rt->rt_expire) { 778 rt->rt_flags &= ~RTF_REJECT; 779 if (la->la_asked == 0 || rt->rt_expire != time_second) { 780 rt->rt_expire = time_second; 781 if (la->la_asked++ < arp_maxtries) 782 arprequest(ifp, 783 &satocsin(rt->rt_ifa->ifa_addr)->sin_addr, 784 &satocsin(dst)->sin_addr, 785 #if NCARP > 0 786 (rt->rt_ifp->if_type == IFT_CARP) ? 787 CLLADDR(rt->rt_ifp->if_sadl): 788 #endif 789 CLLADDR(ifp->if_sadl)); 790 else { 791 rt->rt_flags |= RTF_REJECT; 792 rt->rt_expire += arpt_down; 793 la->la_asked = 0; 794 } 795 } 796 } 797 return (0); 798 } 799 800 /* 801 * Common length and type checks are done here, 802 * then the protocol-specific routine is called. 803 */ 804 void 805 arpintr(void) 806 { 807 struct mbuf *m; 808 struct arphdr *ar; 809 int s; 810 int arplen; 811 812 while (arpintrq.ifq_head) { 813 s = splnet(); 814 IF_DEQUEUE(&arpintrq, m); 815 splx(s); 816 if (m == 0 || (m->m_flags & M_PKTHDR) == 0) 817 panic("arpintr"); 818 819 MCLAIM(m, &arpdomain.dom_mowner); 820 arpstat.as_rcvtotal++; 821 822 /* 823 * First, make sure we have at least struct arphdr. 824 */ 825 if (m->m_len < sizeof(struct arphdr) || 826 (ar = mtod(m, struct arphdr *)) == NULL) 827 goto badlen; 828 829 switch (m->m_pkthdr.rcvif->if_type) { 830 case IFT_IEEE1394: 831 arplen = sizeof(struct arphdr) + 832 ar->ar_hln + 2 * ar->ar_pln; 833 break; 834 default: 835 arplen = sizeof(struct arphdr) + 836 2 * ar->ar_hln + 2 * ar->ar_pln; 837 break; 838 } 839 840 if (/* XXX ntohs(ar->ar_hrd) == ARPHRD_ETHER && */ 841 m->m_len >= arplen) 842 switch (ntohs(ar->ar_pro)) { 843 case ETHERTYPE_IP: 844 case ETHERTYPE_IPTRAILERS: 845 in_arpinput(m); 846 continue; 847 default: 848 arpstat.as_rcvbadproto++; 849 } 850 else { 851 badlen: 852 arpstat.as_rcvbadlen++; 853 } 854 m_freem(m); 855 } 856 } 857 858 /* 859 * ARP for Internet protocols on 10 Mb/s Ethernet. 860 * Algorithm is that given in RFC 826. 861 * In addition, a sanity check is performed on the sender 862 * protocol address, to catch impersonators. 863 * We no longer handle negotiations for use of trailer protocol: 864 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 865 * along with IP replies if we wanted trailers sent to us, 866 * and also sent them in response to IP replies. 867 * This allowed either end to announce the desire to receive 868 * trailer packets. 869 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 870 * but formerly didn't normally send requests. 871 */ 872 static void 873 in_arpinput(struct mbuf *m) 874 { 875 struct arphdr *ah; 876 struct ifnet *ifp = m->m_pkthdr.rcvif; 877 struct llinfo_arp *la = 0; 878 struct rtentry *rt; 879 struct in_ifaddr *ia; 880 #if NBRIDGE > 0 881 struct in_ifaddr *bridge_ia = NULL; 882 #endif 883 #if NCARP > 0 884 u_int32_t count = 0, index = 0; 885 #endif 886 struct sockaddr_dl *sdl; 887 struct sockaddr sa; 888 struct in_addr isaddr, itaddr, myaddr; 889 int op; 890 struct mbuf *mold; 891 void *tha; 892 int s; 893 894 if (__predict_false(m_makewritable(&m, 0, m->m_pkthdr.len, M_DONTWAIT))) 895 goto out; 896 ah = mtod(m, struct arphdr *); 897 op = ntohs(ah->ar_op); 898 899 /* 900 * Fix up ah->ar_hrd if necessary, before using ar_tha() or 901 * ar_tpa(). 902 */ 903 switch (ifp->if_type) { 904 case IFT_IEEE1394: 905 if (ntohs(ah->ar_hrd) == ARPHRD_IEEE1394) 906 ; 907 else { 908 /* XXX this is to make sure we compute ar_tha right */ 909 /* XXX check ar_hrd more strictly? */ 910 ah->ar_hrd = htons(ARPHRD_IEEE1394); 911 } 912 break; 913 default: 914 /* XXX check ar_hrd? */ 915 break; 916 } 917 918 memcpy(&isaddr, ar_spa(ah), sizeof (isaddr)); 919 memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr)); 920 921 if (m->m_flags & (M_BCAST|M_MCAST)) 922 arpstat.as_rcvmcast++; 923 924 /* 925 * If the target IP address is zero, ignore the packet. 926 * This prevents the code below from tring to answer 927 * when we are using IP address zero (booting). 928 */ 929 if (in_nullhost(itaddr)) { 930 arpstat.as_rcvzerotpa++; 931 goto out; 932 } 933 934 /* 935 * If the source IP address is zero, this is most likely a 936 * confused host trying to use IP address zero. (Windoze?) 937 * XXX: Should we bother trying to reply to these? 938 */ 939 if (in_nullhost(isaddr)) { 940 arpstat.as_rcvzerospa++; 941 goto out; 942 } 943 944 /* 945 * Search for a matching interface address 946 * or any address on the interface to use 947 * as a dummy address in the rest of this function 948 */ 949 950 INADDR_TO_IA(itaddr, ia); 951 while (ia != NULL) { 952 #if NCARP > 0 953 if (ia->ia_ifp->if_type == IFT_CARP && 954 ((ia->ia_ifp->if_flags & (IFF_UP|IFF_RUNNING)) == 955 (IFF_UP|IFF_RUNNING))) { 956 index++; 957 if (ia->ia_ifp == m->m_pkthdr.rcvif && 958 carp_iamatch(ia, ar_sha(ah), 959 &count, index)) { 960 break; 961 } 962 } else 963 #endif 964 if (ia->ia_ifp == m->m_pkthdr.rcvif) 965 break; 966 #if NBRIDGE > 0 967 /* 968 * If the interface we received the packet on 969 * is part of a bridge, check to see if we need 970 * to "bridge" the packet to ourselves at this 971 * layer. Note we still prefer a perfect match, 972 * but allow this weaker match if necessary. 973 */ 974 if (m->m_pkthdr.rcvif->if_bridge != NULL && 975 m->m_pkthdr.rcvif->if_bridge == ia->ia_ifp->if_bridge) 976 bridge_ia = ia; 977 #endif /* NBRIDGE > 0 */ 978 979 NEXT_IA_WITH_SAME_ADDR(ia); 980 } 981 982 #if NBRIDGE > 0 983 if (ia == NULL && bridge_ia != NULL) { 984 ia = bridge_ia; 985 ifp = bridge_ia->ia_ifp; 986 } 987 #endif 988 989 if (ia == NULL) { 990 INADDR_TO_IA(isaddr, ia); 991 while ((ia != NULL) && ia->ia_ifp != m->m_pkthdr.rcvif) 992 NEXT_IA_WITH_SAME_ADDR(ia); 993 994 if (ia == NULL) { 995 IFP_TO_IA(ifp, ia); 996 if (ia == NULL) { 997 arpstat.as_rcvnoint++; 998 goto out; 999 } 1000 } 1001 } 1002 1003 myaddr = ia->ia_addr.sin_addr; 1004 1005 /* XXX checks for bridge case? */ 1006 if (!memcmp(ar_sha(ah), CLLADDR(ifp->if_sadl), ifp->if_addrlen)) { 1007 arpstat.as_rcvlocalsha++; 1008 goto out; /* it's from me, ignore it. */ 1009 } 1010 1011 /* XXX checks for bridge case? */ 1012 if (!memcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) { 1013 arpstat.as_rcvbcastsha++; 1014 log(LOG_ERR, 1015 "%s: arp: link address is broadcast for IP address %s!\n", 1016 ifp->if_xname, in_fmtaddr(isaddr)); 1017 goto out; 1018 } 1019 1020 if (in_hosteq(isaddr, myaddr)) { 1021 arpstat.as_rcvlocalspa++; 1022 log(LOG_ERR, 1023 "duplicate IP address %s sent from link address %s\n", 1024 in_fmtaddr(isaddr), lla_snprintf(ar_sha(ah), ah->ar_hln)); 1025 itaddr = myaddr; 1026 goto reply; 1027 } 1028 la = arplookup(m, &isaddr, in_hosteq(itaddr, myaddr), 0); 1029 if (la && (rt = la->la_rt) && (sdl = satosdl(rt->rt_gateway))) { 1030 if (sdl->sdl_alen && 1031 memcmp(ar_sha(ah), CLLADDR(sdl), sdl->sdl_alen)) { 1032 if (rt->rt_flags & RTF_STATIC) { 1033 arpstat.as_rcvoverperm++; 1034 log(LOG_INFO, 1035 "%s tried to overwrite permanent arp info" 1036 " for %s\n", 1037 lla_snprintf(ar_sha(ah), ah->ar_hln), 1038 in_fmtaddr(isaddr)); 1039 goto out; 1040 } else if (rt->rt_ifp != ifp) { 1041 arpstat.as_rcvoverint++; 1042 log(LOG_INFO, 1043 "%s on %s tried to overwrite " 1044 "arp info for %s on %s\n", 1045 lla_snprintf(ar_sha(ah), ah->ar_hln), 1046 ifp->if_xname, in_fmtaddr(isaddr), 1047 rt->rt_ifp->if_xname); 1048 goto out; 1049 } else { 1050 arpstat.as_rcvover++; 1051 log(LOG_INFO, 1052 "arp info overwritten for %s by %s\n", 1053 in_fmtaddr(isaddr), 1054 lla_snprintf(ar_sha(ah), ah->ar_hln)); 1055 } 1056 } 1057 /* 1058 * sanity check for the address length. 1059 * XXX this does not work for protocols with variable address 1060 * length. -is 1061 */ 1062 if (sdl->sdl_alen && 1063 sdl->sdl_alen != ah->ar_hln) { 1064 arpstat.as_rcvlenchg++; 1065 log(LOG_WARNING, 1066 "arp from %s: new addr len %d, was %d", 1067 in_fmtaddr(isaddr), ah->ar_hln, sdl->sdl_alen); 1068 } 1069 if (ifp->if_addrlen != ah->ar_hln) { 1070 arpstat.as_rcvbadlen++; 1071 log(LOG_WARNING, 1072 "arp from %s: addr len: new %d, i/f %d (ignored)", 1073 in_fmtaddr(isaddr), ah->ar_hln, 1074 ifp->if_addrlen); 1075 goto reply; 1076 } 1077 #if NTOKEN > 0 1078 /* 1079 * XXX uses m_data and assumes the complete answer including 1080 * XXX token-ring headers is in the same buf 1081 */ 1082 if (ifp->if_type == IFT_ISO88025) { 1083 struct token_header *trh; 1084 1085 trh = (struct token_header *)M_TRHSTART(m); 1086 if (trh->token_shost[0] & TOKEN_RI_PRESENT) { 1087 struct token_rif *rif; 1088 size_t riflen; 1089 1090 rif = TOKEN_RIF(trh); 1091 riflen = (ntohs(rif->tr_rcf) & 1092 TOKEN_RCF_LEN_MASK) >> 8; 1093 1094 if (riflen > 2 && 1095 riflen < sizeof(struct token_rif) && 1096 (riflen & 1) == 0) { 1097 rif->tr_rcf ^= htons(TOKEN_RCF_DIRECTION); 1098 rif->tr_rcf &= htons(~TOKEN_RCF_BROADCAST_MASK); 1099 bcopy(rif, TOKEN_RIF(la), riflen); 1100 } 1101 } 1102 } 1103 #endif /* NTOKEN > 0 */ 1104 (void)sockaddr_dl_setaddr(sdl, sdl->sdl_len, ar_sha(ah), 1105 ah->ar_hln); 1106 if (rt->rt_expire) 1107 rt->rt_expire = time_second + arpt_keep; 1108 rt->rt_flags &= ~RTF_REJECT; 1109 la->la_asked = 0; 1110 1111 s = splnet(); 1112 mold = la->la_hold; 1113 la->la_hold = 0; 1114 splx(s); 1115 1116 if (mold) { 1117 arpstat.as_dfrsent++; 1118 (*ifp->if_output)(ifp, mold, rt_getkey(rt), rt); 1119 } 1120 } 1121 reply: 1122 if (op != ARPOP_REQUEST) { 1123 if (op == ARPOP_REPLY) 1124 arpstat.as_rcvreply++; 1125 out: 1126 m_freem(m); 1127 return; 1128 } 1129 arpstat.as_rcvrequest++; 1130 if (in_hosteq(itaddr, myaddr)) { 1131 /* I am the target */ 1132 tha = ar_tha(ah); 1133 if (tha) 1134 memcpy(tha, ar_sha(ah), ah->ar_hln); 1135 memcpy(ar_sha(ah), CLLADDR(ifp->if_sadl), ah->ar_hln); 1136 } else { 1137 la = arplookup(m, &itaddr, 0, SIN_PROXY); 1138 if (la == 0) 1139 goto out; 1140 rt = la->la_rt; 1141 if (rt->rt_ifp->if_type == IFT_CARP && 1142 m->m_pkthdr.rcvif->if_type != IFT_CARP) 1143 goto out; 1144 tha = ar_tha(ah); 1145 if (tha) 1146 memcpy(tha, ar_sha(ah), ah->ar_hln); 1147 sdl = satosdl(rt->rt_gateway); 1148 memcpy(ar_sha(ah), CLLADDR(sdl), ah->ar_hln); 1149 } 1150 1151 memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln); 1152 memcpy(ar_spa(ah), &itaddr, ah->ar_pln); 1153 ah->ar_op = htons(ARPOP_REPLY); 1154 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 1155 switch (ifp->if_type) { 1156 case IFT_IEEE1394: 1157 /* 1158 * ieee1394 arp reply is broadcast 1159 */ 1160 m->m_flags &= ~M_MCAST; 1161 m->m_flags |= M_BCAST; 1162 m->m_len = sizeof(*ah) + (2 * ah->ar_pln) + ah->ar_hln; 1163 break; 1164 1165 default: 1166 m->m_flags &= ~(M_BCAST|M_MCAST); /* never reply by broadcast */ 1167 m->m_len = sizeof(*ah) + (2 * ah->ar_pln) + (2 * ah->ar_hln); 1168 break; 1169 } 1170 m->m_pkthdr.len = m->m_len; 1171 sa.sa_family = AF_ARP; 1172 sa.sa_len = 2; 1173 arpstat.as_sndtotal++; 1174 arpstat.as_sndreply++; 1175 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 1176 return; 1177 } 1178 1179 /* 1180 * Free an arp entry. 1181 */ 1182 static void arptfree(struct llinfo_arp *la) 1183 { 1184 struct rtentry *rt = la->la_rt; 1185 struct sockaddr_dl *sdl; 1186 1187 ARP_LOCK_CHECK(); 1188 1189 if (rt == 0) 1190 panic("arptfree"); 1191 if (rt->rt_refcnt > 0 && (sdl = satosdl(rt->rt_gateway)) && 1192 sdl->sdl_family == AF_LINK) { 1193 sdl->sdl_alen = 0; 1194 la->la_asked = 0; 1195 rt->rt_flags &= ~RTF_REJECT; 1196 return; 1197 } 1198 rtrequest(RTM_DELETE, rt_getkey(rt), NULL, rt_mask(rt), 0, NULL); 1199 } 1200 1201 static struct llinfo_arp * 1202 arplookup(struct mbuf *m, const struct in_addr *addr, int create, int proxy) 1203 { 1204 return arplookup1(m, addr, create, proxy, NULL); 1205 } 1206 1207 /* 1208 * Lookup or enter a new address in arptab. 1209 */ 1210 static struct llinfo_arp * 1211 arplookup1(struct mbuf *m, const struct in_addr *addr, int create, int proxy, 1212 struct rtentry *rt0) 1213 { 1214 struct arphdr *ah; 1215 struct ifnet *ifp = m->m_pkthdr.rcvif; 1216 struct rtentry *rt; 1217 static struct sockaddr_inarp sin; 1218 const char *why = 0; 1219 1220 ah = mtod(m, struct arphdr *); 1221 if (rt0 == NULL) { 1222 sin.sin_len = sizeof(sin); 1223 sin.sin_family = AF_INET; 1224 sin.sin_addr = *addr; 1225 sin.sin_other = proxy ? SIN_PROXY : 0; 1226 rt = rtalloc1(sintosa(&sin), create); 1227 if (rt == NULL) 1228 return (NULL); 1229 rt->rt_refcnt--; 1230 } else 1231 rt = rt0; 1232 1233 #define IS_LLINFO(__rt) \ 1234 (((__rt)->rt_flags & (RTF_GATEWAY | RTF_LLINFO)) == RTF_LLINFO && \ 1235 (__rt)->rt_gateway->sa_family == AF_LINK) 1236 1237 1238 if (IS_LLINFO(rt)) 1239 return ((struct llinfo_arp *)rt->rt_llinfo); 1240 1241 if (create) { 1242 if (rt->rt_flags & RTF_GATEWAY) 1243 why = "host is not on local network"; 1244 else if ((rt->rt_flags & RTF_LLINFO) == 0) { 1245 arpstat.as_allocfail++; 1246 why = "could not allocate llinfo"; 1247 } else 1248 why = "gateway route is not ours"; 1249 log(LOG_DEBUG, "arplookup: unable to enter address" 1250 " for %s@%s on %s (%s)\n", 1251 in_fmtaddr(*addr), lla_snprintf(ar_sha(ah), ah->ar_hln), 1252 (ifp) ? ifp->if_xname : 0, why); 1253 if (rt->rt_refcnt <= 0 && (rt->rt_flags & RTF_CLONED) != 0) { 1254 rtrequest(RTM_DELETE, rt_getkey(rt), 1255 rt->rt_gateway, rt_mask(rt), rt->rt_flags, 0); 1256 } 1257 } 1258 return (0); 1259 } 1260 1261 int 1262 arpioctl(u_long cmd, void *data) 1263 { 1264 1265 return (EOPNOTSUPP); 1266 } 1267 1268 void 1269 arp_ifinit(struct ifnet *ifp, struct ifaddr *ifa) 1270 { 1271 struct in_addr *ip; 1272 1273 /* 1274 * Warn the user if another station has this IP address, 1275 * but only if the interface IP address is not zero. 1276 */ 1277 ip = &IA_SIN(ifa)->sin_addr; 1278 if (!in_nullhost(*ip)) 1279 arprequest(ifp, ip, ip, CLLADDR(ifp->if_sadl)); 1280 1281 ifa->ifa_rtrequest = arp_rtrequest; 1282 ifa->ifa_flags |= RTF_CLONING; 1283 } 1284 1285 /* 1286 * Called from 10 Mb/s Ethernet interrupt handlers 1287 * when ether packet type ETHERTYPE_REVARP 1288 * is received. Common length and type checks are done here, 1289 * then the protocol-specific routine is called. 1290 */ 1291 void 1292 revarpinput(struct mbuf *m) 1293 { 1294 struct arphdr *ar; 1295 1296 if (m->m_len < sizeof(struct arphdr)) 1297 goto out; 1298 ar = mtod(m, struct arphdr *); 1299 #if 0 /* XXX I don't think we need this... and it will prevent other LL */ 1300 if (ntohs(ar->ar_hrd) != ARPHRD_ETHER) 1301 goto out; 1302 #endif 1303 if (m->m_len < sizeof(struct arphdr) + 2 * (ar->ar_hln + ar->ar_pln)) 1304 goto out; 1305 switch (ntohs(ar->ar_pro)) { 1306 case ETHERTYPE_IP: 1307 case ETHERTYPE_IPTRAILERS: 1308 in_revarpinput(m); 1309 return; 1310 1311 default: 1312 break; 1313 } 1314 out: 1315 m_freem(m); 1316 } 1317 1318 /* 1319 * RARP for Internet protocols on 10 Mb/s Ethernet. 1320 * Algorithm is that given in RFC 903. 1321 * We are only using for bootstrap purposes to get an ip address for one of 1322 * our interfaces. Thus we support no user-interface. 1323 * 1324 * Since the contents of the RARP reply are specific to the interface that 1325 * sent the request, this code must ensure that they are properly associated. 1326 * 1327 * Note: also supports ARP via RARP packets, per the RFC. 1328 */ 1329 void 1330 in_revarpinput(struct mbuf *m) 1331 { 1332 struct ifnet *ifp; 1333 struct arphdr *ah; 1334 void *tha; 1335 int op; 1336 1337 ah = mtod(m, struct arphdr *); 1338 op = ntohs(ah->ar_op); 1339 1340 switch (m->m_pkthdr.rcvif->if_type) { 1341 case IFT_IEEE1394: 1342 /* ARP without target hardware address is not supported */ 1343 goto out; 1344 default: 1345 break; 1346 } 1347 1348 switch (op) { 1349 case ARPOP_REQUEST: 1350 case ARPOP_REPLY: /* per RFC */ 1351 in_arpinput(m); 1352 return; 1353 case ARPOP_REVREPLY: 1354 break; 1355 case ARPOP_REVREQUEST: /* handled by rarpd(8) */ 1356 default: 1357 goto out; 1358 } 1359 if (!revarp_in_progress) 1360 goto out; 1361 ifp = m->m_pkthdr.rcvif; 1362 if (ifp != myip_ifp) /* !same interface */ 1363 goto out; 1364 if (myip_initialized) 1365 goto wake; 1366 tha = ar_tha(ah); 1367 KASSERT(tha); 1368 if (bcmp(tha, CLLADDR(ifp->if_sadl), ifp->if_sadl->sdl_alen)) 1369 goto out; 1370 memcpy(&srv_ip, ar_spa(ah), sizeof(srv_ip)); 1371 memcpy(&myip, ar_tpa(ah), sizeof(myip)); 1372 myip_initialized = 1; 1373 wake: /* Do wakeup every time in case it was missed. */ 1374 wakeup((void *)&myip); 1375 1376 out: 1377 m_freem(m); 1378 } 1379 1380 /* 1381 * Send a RARP request for the ip address of the specified interface. 1382 * The request should be RFC 903-compliant. 1383 */ 1384 void 1385 revarprequest(struct ifnet *ifp) 1386 { 1387 struct sockaddr sa; 1388 struct mbuf *m; 1389 struct arphdr *ah; 1390 void *tha; 1391 1392 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 1393 return; 1394 MCLAIM(m, &arpdomain.dom_mowner); 1395 m->m_len = sizeof(*ah) + 2*sizeof(struct in_addr) + 1396 2*ifp->if_addrlen; 1397 m->m_pkthdr.len = m->m_len; 1398 MH_ALIGN(m, m->m_len); 1399 ah = mtod(m, struct arphdr *); 1400 bzero((void *)ah, m->m_len); 1401 ah->ar_pro = htons(ETHERTYPE_IP); 1402 ah->ar_hln = ifp->if_addrlen; /* hardware address length */ 1403 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 1404 ah->ar_op = htons(ARPOP_REVREQUEST); 1405 1406 memcpy(ar_sha(ah), CLLADDR(ifp->if_sadl), ah->ar_hln); 1407 tha = ar_tha(ah); 1408 KASSERT(tha); 1409 bcopy(CLLADDR(ifp->if_sadl), tha, ah->ar_hln); 1410 1411 sa.sa_family = AF_ARP; 1412 sa.sa_len = 2; 1413 m->m_flags |= M_BCAST; 1414 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 1415 1416 } 1417 1418 /* 1419 * RARP for the ip address of the specified interface, but also 1420 * save the ip address of the server that sent the answer. 1421 * Timeout if no response is received. 1422 */ 1423 int 1424 revarpwhoarewe(struct ifnet *ifp, struct in_addr *serv_in, 1425 struct in_addr *clnt_in) 1426 { 1427 int result, count = 20; 1428 1429 myip_initialized = 0; 1430 myip_ifp = ifp; 1431 1432 revarp_in_progress = 1; 1433 while (count--) { 1434 revarprequest(ifp); 1435 result = tsleep((void *)&myip, PSOCK, "revarp", hz/2); 1436 if (result != EWOULDBLOCK) 1437 break; 1438 } 1439 revarp_in_progress = 0; 1440 1441 if (!myip_initialized) 1442 return ENETUNREACH; 1443 1444 bcopy((void *)&srv_ip, serv_in, sizeof(*serv_in)); 1445 bcopy((void *)&myip, clnt_in, sizeof(*clnt_in)); 1446 return 0; 1447 } 1448 1449 1450 1451 #ifdef DDB 1452 1453 #include <machine/db_machdep.h> 1454 #include <ddb/db_interface.h> 1455 #include <ddb/db_output.h> 1456 1457 static void 1458 db_print_sa(const struct sockaddr *sa) 1459 { 1460 int len; 1461 const u_char *p; 1462 1463 if (sa == 0) { 1464 db_printf("[NULL]"); 1465 return; 1466 } 1467 1468 p = (const u_char *)sa; 1469 len = sa->sa_len; 1470 db_printf("["); 1471 while (len > 0) { 1472 db_printf("%d", *p); 1473 p++; len--; 1474 if (len) db_printf(","); 1475 } 1476 db_printf("]\n"); 1477 } 1478 1479 static void 1480 db_print_ifa(struct ifaddr *ifa) 1481 { 1482 if (ifa == 0) 1483 return; 1484 db_printf(" ifa_addr="); 1485 db_print_sa(ifa->ifa_addr); 1486 db_printf(" ifa_dsta="); 1487 db_print_sa(ifa->ifa_dstaddr); 1488 db_printf(" ifa_mask="); 1489 db_print_sa(ifa->ifa_netmask); 1490 db_printf(" flags=0x%x,refcnt=%d,metric=%d\n", 1491 ifa->ifa_flags, 1492 ifa->ifa_refcnt, 1493 ifa->ifa_metric); 1494 } 1495 1496 static void 1497 db_print_llinfo(void *li) 1498 { 1499 struct llinfo_arp *la; 1500 1501 if (li == 0) 1502 return; 1503 la = (struct llinfo_arp *)li; 1504 db_printf(" la_rt=%p la_hold=%p, la_asked=0x%lx\n", 1505 la->la_rt, la->la_hold, la->la_asked); 1506 } 1507 1508 /* 1509 * Function to pass to rt_walktree(). 1510 * Return non-zero error to abort walk. 1511 */ 1512 static int 1513 db_show_rtentry(struct rtentry *rt, void *w) 1514 { 1515 db_printf("rtentry=%p", rt); 1516 1517 db_printf(" flags=0x%x refcnt=%d use=%ld expire=%ld\n", 1518 rt->rt_flags, rt->rt_refcnt, 1519 rt->rt_use, rt->rt_expire); 1520 1521 db_printf(" key="); db_print_sa(rt_getkey(rt)); 1522 db_printf(" mask="); db_print_sa(rt_mask(rt)); 1523 db_printf(" gw="); db_print_sa(rt->rt_gateway); 1524 1525 db_printf(" ifp=%p ", rt->rt_ifp); 1526 if (rt->rt_ifp) 1527 db_printf("(%s)", rt->rt_ifp->if_xname); 1528 else 1529 db_printf("(NULL)"); 1530 1531 db_printf(" ifa=%p\n", rt->rt_ifa); 1532 db_print_ifa(rt->rt_ifa); 1533 1534 db_printf(" gwroute=%p llinfo=%p\n", 1535 rt->rt_gwroute, rt->rt_llinfo); 1536 db_print_llinfo(rt->rt_llinfo); 1537 1538 return (0); 1539 } 1540 1541 /* 1542 * Function to print all the route trees. 1543 * Use this from ddb: "show arptab" 1544 */ 1545 void 1546 db_show_arptab(db_expr_t addr, bool have_addr, 1547 db_expr_t count, const char *modif) 1548 { 1549 rt_walktree(AF_INET, db_show_rtentry, NULL); 1550 } 1551 #endif 1552 1553 SYSCTL_SETUP(sysctl_net_inet_arp_setup, "sysctl net.inet.arp subtree setup") 1554 { 1555 const struct sysctlnode *node; 1556 1557 sysctl_createv(clog, 0, NULL, NULL, 1558 CTLFLAG_PERMANENT, 1559 CTLTYPE_NODE, "net", NULL, 1560 NULL, 0, NULL, 0, 1561 CTL_NET, CTL_EOL); 1562 sysctl_createv(clog, 0, NULL, NULL, 1563 CTLFLAG_PERMANENT, 1564 CTLTYPE_NODE, "inet", NULL, 1565 NULL, 0, NULL, 0, 1566 CTL_NET, PF_INET, CTL_EOL); 1567 sysctl_createv(clog, 0, NULL, &node, 1568 CTLFLAG_PERMANENT, 1569 CTLTYPE_NODE, "arp", 1570 SYSCTL_DESCR("Address Resolution Protocol"), 1571 NULL, 0, NULL, 0, 1572 CTL_NET, PF_INET, CTL_CREATE, CTL_EOL); 1573 1574 sysctl_createv(clog, 0, NULL, NULL, 1575 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1576 CTLTYPE_INT, "prune", 1577 SYSCTL_DESCR("ARP cache pruning interval"), 1578 NULL, 0, &arpt_prune, 0, 1579 CTL_NET,PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL); 1580 1581 sysctl_createv(clog, 0, NULL, NULL, 1582 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1583 CTLTYPE_INT, "keep", 1584 SYSCTL_DESCR("Valid ARP entry lifetime"), 1585 NULL, 0, &arpt_keep, 0, 1586 CTL_NET,PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL); 1587 1588 sysctl_createv(clog, 0, NULL, NULL, 1589 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1590 CTLTYPE_INT, "down", 1591 SYSCTL_DESCR("Failed ARP entry lifetime"), 1592 NULL, 0, &arpt_down, 0, 1593 CTL_NET,PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL); 1594 1595 sysctl_createv(clog, 0, NULL, NULL, 1596 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1597 CTLTYPE_INT, "refresh", 1598 SYSCTL_DESCR("ARP entry refresh interval"), 1599 NULL, 0, &arpt_refresh, 0, 1600 CTL_NET,PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL); 1601 } 1602 1603 #endif /* INET */ 1604