1 /* $NetBSD: if_arp.c,v 1.34 1996/10/13 02:03:00 christos Exp $ */ 2 3 /* 4 * Copyright (c) 1982, 1986, 1988, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 * 35 * @(#)if_ether.c 8.1 (Berkeley) 6/10/93 36 */ 37 38 /* 39 * Ethernet address resolution protocol. 40 * TODO: 41 * add "inuse/lock" bit (or ref. count) along with valid bit 42 */ 43 44 #ifdef INET 45 46 #include <sys/param.h> 47 #include <sys/systm.h> 48 #include <sys/malloc.h> 49 #include <sys/mbuf.h> 50 #include <sys/socket.h> 51 #include <sys/time.h> 52 #include <sys/kernel.h> 53 #include <sys/errno.h> 54 #include <sys/ioctl.h> 55 #include <sys/syslog.h> 56 #include <sys/proc.h> 57 58 #include <net/if.h> 59 #include <net/if_dl.h> 60 #include <net/route.h> 61 62 #include <netinet/in.h> 63 #include <netinet/in_systm.h> 64 #include <netinet/in_var.h> 65 #include <netinet/ip.h> 66 #include <netinet/if_ether.h> 67 68 #define SIN(s) ((struct sockaddr_in *)s) 69 #define SDL(s) ((struct sockaddr_dl *)s) 70 #define SRP(s) ((struct sockaddr_inarp *)s) 71 72 /* 73 * ARP trailer negotiation. Trailer protocol is not IP specific, 74 * but ARP request/response use IP addresses. 75 */ 76 #define ETHERTYPE_IPTRAILERS ETHERTYPE_TRAIL 77 78 /* timer values */ 79 int arpt_prune = (5*60*1); /* walk list every 5 minutes */ 80 int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */ 81 int arpt_down = 20; /* once declared down, don't send for 20 secs */ 82 #define rt_expire rt_rmx.rmx_expire 83 84 static void arprequest 85 __P((struct arpcom *, u_int32_t *, u_int32_t *, u_int8_t *)); 86 static void arptfree __P((struct llinfo_arp *)); 87 static void arptimer __P((void *)); 88 static struct llinfo_arp *arplookup __P((u_int32_t, int, int)); 89 static void in_arpinput __P((struct mbuf *)); 90 91 extern struct ifnet loif; 92 LIST_HEAD(, llinfo_arp) llinfo_arp; 93 struct ifqueue arpintrq = {0, 0, 0, 50}; 94 int arp_inuse, arp_allocated, arp_intimer; 95 int arp_maxtries = 5; 96 int useloopback = 1; /* use loopback interface for local traffic */ 97 int arpinit_done = 0; 98 99 /* revarp state */ 100 static struct in_addr myip, srv_ip; 101 static int myip_initialized = 0; 102 static int revarp_in_progress = 0; 103 static struct ifnet *myip_ifp = NULL; 104 105 static void arptimer __P((void *)); 106 static void arprequest __P((struct arpcom *, u_int32_t *, u_int32_t *, 107 u_int8_t *)); 108 static void in_arpinput __P((struct mbuf *)); 109 static void arptfree __P((struct llinfo_arp *)); 110 static struct llinfo_arp *arplookup __P((u_int32_t, int, int )); 111 #ifdef DDB 112 static void db_print_sa __P((struct sockaddr *)); 113 static void db_print_ifa __P((struct ifaddr *)); 114 static void db_print_llinfo __P((caddr_t)); 115 static int db_show_radix_node __P((struct radix_node *, void *)); 116 #endif 117 118 /* 119 * Timeout routine. Age arp_tab entries periodically. 120 */ 121 /* ARGSUSED */ 122 static void 123 arptimer(arg) 124 void *arg; 125 { 126 int s; 127 register struct llinfo_arp *la, *nla; 128 129 s = splsoftnet(); 130 timeout(arptimer, NULL, arpt_prune * hz); 131 for (la = llinfo_arp.lh_first; la != 0; la = nla) { 132 register struct rtentry *rt = la->la_rt; 133 134 nla = la->la_list.le_next; 135 if (rt->rt_expire && rt->rt_expire <= time.tv_sec) 136 arptfree(la); /* timer has expired; clear */ 137 } 138 splx(s); 139 } 140 141 /* 142 * Parallel to llc_rtrequest. 143 */ 144 void 145 arp_rtrequest(req, rt, sa) 146 int req; 147 register struct rtentry *rt; 148 struct sockaddr *sa; 149 { 150 register struct sockaddr *gate = rt->rt_gateway; 151 register struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo; 152 static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK}; 153 154 if (!arpinit_done) { 155 arpinit_done = 1; 156 /* 157 * We generate expiration times from time.tv_sec 158 * so avoid accidently creating permanent routes. 159 */ 160 if (time.tv_sec == 0) { 161 time.tv_sec++; 162 } 163 timeout(arptimer, (caddr_t)0, hz); 164 } 165 if (rt->rt_flags & RTF_GATEWAY) 166 return; 167 switch (req) { 168 169 case RTM_ADD: 170 /* 171 * XXX: If this is a manually added route to interface 172 * such as older version of routed or gated might provide, 173 * restore cloning bit. 174 */ 175 if ((rt->rt_flags & RTF_HOST) == 0 && 176 SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff) 177 rt->rt_flags |= RTF_CLONING; 178 if (rt->rt_flags & RTF_CLONING) { 179 /* 180 * Case 1: This route should come from a route to iface. 181 */ 182 rt_setgate(rt, rt_key(rt), 183 (struct sockaddr *)&null_sdl); 184 gate = rt->rt_gateway; 185 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 186 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 187 /* 188 * Give this route an expiration time, even though 189 * it's a "permanent" route, so that routes cloned 190 * from it do not need their expiration time set. 191 */ 192 rt->rt_expire = time.tv_sec; 193 break; 194 } 195 /* Announce a new entry if requested. */ 196 if (rt->rt_flags & RTF_ANNOUNCE) 197 arprequest((struct arpcom *)rt->rt_ifp, 198 &SIN(rt_key(rt))->sin_addr.s_addr, 199 &SIN(rt_key(rt))->sin_addr.s_addr, 200 (u_char *)LLADDR(SDL(gate))); 201 /*FALLTHROUGH*/ 202 case RTM_RESOLVE: 203 if (gate->sa_family != AF_LINK || 204 gate->sa_len < sizeof(null_sdl)) { 205 log(LOG_DEBUG, "arp_rtrequest: bad gateway value"); 206 break; 207 } 208 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 209 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 210 if (la != 0) 211 break; /* This happens on a route change */ 212 /* 213 * Case 2: This route may come from cloning, or a manual route 214 * add with a LL address. 215 */ 216 R_Malloc(la, struct llinfo_arp *, sizeof(*la)); 217 rt->rt_llinfo = (caddr_t)la; 218 if (la == 0) { 219 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); 220 break; 221 } 222 arp_inuse++, arp_allocated++; 223 Bzero(la, sizeof(*la)); 224 la->la_rt = rt; 225 rt->rt_flags |= RTF_LLINFO; 226 LIST_INSERT_HEAD(&llinfo_arp, la, la_list); 227 if (SIN(rt_key(rt))->sin_addr.s_addr == 228 (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) { 229 /* 230 * This test used to be 231 * if (loif.if_flags & IFF_UP) 232 * It allowed local traffic to be forced through 233 * the hardware by configuring the loopback down. 234 * However, it causes problems during network 235 * configuration for boards that can't receive 236 * packets they send. It is now necessary to clear 237 * "useloopback" and remove the route to force 238 * traffic out to the hardware. 239 */ 240 rt->rt_expire = 0; 241 Bcopy(((struct arpcom *)rt->rt_ifp)->ac_enaddr, 242 LLADDR(SDL(gate)), 243 SDL(gate)->sdl_alen = ETHER_ADDR_LEN); 244 if (useloopback) 245 rt->rt_ifp = &loif; 246 } 247 break; 248 249 case RTM_DELETE: 250 if (la == 0) 251 break; 252 arp_inuse--; 253 LIST_REMOVE(la, la_list); 254 rt->rt_llinfo = 0; 255 rt->rt_flags &= ~RTF_LLINFO; 256 if (la->la_hold) 257 m_freem(la->la_hold); 258 Free((caddr_t)la); 259 } 260 } 261 262 /* 263 * Broadcast an ARP request. Caller specifies: 264 * - arp header source ip address 265 * - arp header target ip address 266 * - arp header source ethernet address 267 */ 268 static void 269 arprequest(ac, sip, tip, enaddr) 270 register struct arpcom *ac; 271 register u_int32_t *sip, *tip; 272 register u_int8_t *enaddr; 273 { 274 register struct mbuf *m; 275 register struct ether_header *eh; 276 register struct ether_arp *ea; 277 struct sockaddr sa; 278 279 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 280 return; 281 m->m_len = sizeof(*ea); 282 m->m_pkthdr.len = sizeof(*ea); 283 MH_ALIGN(m, sizeof(*ea)); 284 ea = mtod(m, struct ether_arp *); 285 eh = (struct ether_header *)sa.sa_data; 286 bzero((caddr_t)ea, sizeof (*ea)); 287 bcopy((caddr_t)etherbroadcastaddr, (caddr_t)eh->ether_dhost, 288 sizeof(eh->ether_dhost)); 289 eh->ether_type = htons(ETHERTYPE_ARP); /* if_output will not swap */ 290 ea->arp_hrd = htons(ARPHRD_ETHER); 291 ea->arp_pro = htons(ETHERTYPE_IP); 292 ea->arp_hln = sizeof(ea->arp_sha); /* hardware address length */ 293 ea->arp_pln = sizeof(ea->arp_spa); /* protocol address length */ 294 ea->arp_op = htons(ARPOP_REQUEST); 295 bcopy((caddr_t)enaddr, (caddr_t)ea->arp_sha, sizeof(ea->arp_sha)); 296 bcopy((caddr_t)sip, (caddr_t)ea->arp_spa, sizeof(ea->arp_spa)); 297 bcopy((caddr_t)tip, (caddr_t)ea->arp_tpa, sizeof(ea->arp_tpa)); 298 sa.sa_family = AF_UNSPEC; 299 sa.sa_len = sizeof(sa); 300 (*ac->ac_if.if_output)(&ac->ac_if, m, &sa, (struct rtentry *)0); 301 } 302 303 /* 304 * Resolve an IP address into an ethernet address. If success, 305 * desten is filled in. If there is no entry in arptab, 306 * set one up and broadcast a request for the IP address. 307 * Hold onto this mbuf and resend it once the address 308 * is finally resolved. A return value of 1 indicates 309 * that desten has been filled in and the packet should be sent 310 * normally; a 0 return indicates that the packet has been 311 * taken over here, either now or for later transmission. 312 */ 313 int 314 arpresolve(ac, rt, m, dst, desten) 315 register struct arpcom *ac; 316 register struct rtentry *rt; 317 struct mbuf *m; 318 register struct sockaddr *dst; 319 register u_char *desten; 320 { 321 register struct llinfo_arp *la; 322 struct sockaddr_dl *sdl; 323 324 if (m->m_flags & M_BCAST) { /* broadcast */ 325 bcopy((caddr_t)etherbroadcastaddr, (caddr_t)desten, 326 sizeof(etherbroadcastaddr)); 327 return (1); 328 } 329 if (m->m_flags & M_MCAST) { /* multicast */ 330 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); 331 return (1); 332 } 333 if (rt) 334 la = (struct llinfo_arp *)rt->rt_llinfo; 335 else { 336 if ((la = arplookup(SIN(dst)->sin_addr.s_addr, 1, 0)) != NULL) 337 rt = la->la_rt; 338 } 339 if (la == 0 || rt == 0) { 340 log(LOG_DEBUG, "arpresolve: can't allocate llinfo"); 341 m_freem(m); 342 return (0); 343 } 344 sdl = SDL(rt->rt_gateway); 345 /* 346 * Check the address family and length is valid, the address 347 * is resolved; otherwise, try to resolve. 348 */ 349 if ((rt->rt_expire == 0 || rt->rt_expire > time.tv_sec) && 350 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 351 bcopy(LLADDR(sdl), desten, sdl->sdl_alen); 352 return 1; 353 } 354 /* 355 * There is an arptab entry, but no ethernet address 356 * response yet. Replace the held mbuf with this 357 * latest one. 358 */ 359 if (la->la_hold) 360 m_freem(la->la_hold); 361 la->la_hold = m; 362 /* 363 * Re-send the ARP request when appropriate. 364 */ 365 #ifdef DIAGNOSTIC 366 if (rt->rt_expire == 0) { 367 /* This should never happen. (Should it? -gwr) */ 368 printf("arpresolve: unresolved and rt_expire == 0\n"); 369 /* Set expiration time to now (expired). */ 370 rt->rt_expire = time.tv_sec; 371 } 372 #endif 373 if (rt->rt_expire) { 374 rt->rt_flags &= ~RTF_REJECT; 375 if (la->la_asked == 0 || rt->rt_expire != time.tv_sec) { 376 rt->rt_expire = time.tv_sec; 377 if (la->la_asked++ < arp_maxtries) 378 arprequest(ac, 379 &(SIN(rt->rt_ifa->ifa_addr)->sin_addr.s_addr), 380 &(SIN(dst)->sin_addr.s_addr), 381 ac->ac_enaddr); 382 else { 383 rt->rt_flags |= RTF_REJECT; 384 rt->rt_expire += arpt_down; 385 la->la_asked = 0; 386 } 387 } 388 } 389 return (0); 390 } 391 392 /* 393 * Common length and type checks are done here, 394 * then the protocol-specific routine is called. 395 */ 396 void 397 arpintr() 398 { 399 register struct mbuf *m; 400 register struct arphdr *ar; 401 int s; 402 403 while (arpintrq.ifq_head) { 404 s = splimp(); 405 IF_DEQUEUE(&arpintrq, m); 406 splx(s); 407 if (m == 0 || (m->m_flags & M_PKTHDR) == 0) 408 panic("arpintr"); 409 if (m->m_len >= sizeof(struct arphdr) && 410 (ar = mtod(m, struct arphdr *)) && 411 ntohs(ar->ar_hrd) == ARPHRD_ETHER && 412 m->m_len >= 413 sizeof(struct arphdr) + 2 * (ar->ar_hln + ar->ar_pln)) 414 switch (ntohs(ar->ar_pro)) { 415 416 case ETHERTYPE_IP: 417 case ETHERTYPE_IPTRAILERS: 418 in_arpinput(m); 419 continue; 420 } 421 m_freem(m); 422 } 423 } 424 425 /* 426 * ARP for Internet protocols on 10 Mb/s Ethernet. 427 * Algorithm is that given in RFC 826. 428 * In addition, a sanity check is performed on the sender 429 * protocol address, to catch impersonators. 430 * We no longer handle negotiations for use of trailer protocol: 431 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 432 * along with IP replies if we wanted trailers sent to us, 433 * and also sent them in response to IP replies. 434 * This allowed either end to announce the desire to receive 435 * trailer packets. 436 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 437 * but formerly didn't normally send requests. 438 */ 439 static void 440 in_arpinput(m) 441 struct mbuf *m; 442 { 443 register struct ether_arp *ea; 444 register struct arpcom *ac = (struct arpcom *)m->m_pkthdr.rcvif; 445 struct ether_header *eh; 446 register struct llinfo_arp *la = 0; 447 register struct rtentry *rt; 448 struct in_ifaddr *ia, *maybe_ia = 0; 449 struct sockaddr_dl *sdl; 450 struct sockaddr sa; 451 struct in_addr isaddr, itaddr, myaddr; 452 int op; 453 454 ea = mtod(m, struct ether_arp *); 455 op = ntohs(ea->arp_op); 456 bcopy((caddr_t)ea->arp_spa, (caddr_t)&isaddr, sizeof (isaddr)); 457 bcopy((caddr_t)ea->arp_tpa, (caddr_t)&itaddr, sizeof (itaddr)); 458 for (ia = in_ifaddr.tqh_first; ia != 0; ia = ia->ia_list.tqe_next) 459 if (ia->ia_ifp == &ac->ac_if) { 460 maybe_ia = ia; 461 if (itaddr.s_addr == ia->ia_addr.sin_addr.s_addr || 462 isaddr.s_addr == ia->ia_addr.sin_addr.s_addr) 463 break; 464 } 465 if (maybe_ia == 0) 466 goto out; 467 myaddr = ia ? ia->ia_addr.sin_addr : maybe_ia->ia_addr.sin_addr; 468 if (!bcmp((caddr_t)ea->arp_sha, (caddr_t)ac->ac_enaddr, 469 sizeof (ea->arp_sha))) 470 goto out; /* it's from me, ignore it. */ 471 if (!bcmp((caddr_t)ea->arp_sha, (caddr_t)etherbroadcastaddr, 472 sizeof (ea->arp_sha))) { 473 log(LOG_ERR, 474 "arp: ether address is broadcast for IP address %x!\n", 475 ntohl(isaddr.s_addr)); 476 goto out; 477 } 478 if (isaddr.s_addr == myaddr.s_addr) { 479 log(LOG_ERR, 480 "duplicate IP address %08x sent from ethernet address %s\n", 481 ntohl(isaddr.s_addr), ether_sprintf(ea->arp_sha)); 482 itaddr = myaddr; 483 goto reply; 484 } 485 la = arplookup(isaddr.s_addr, itaddr.s_addr == myaddr.s_addr, 0); 486 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { 487 if (sdl->sdl_alen && 488 bcmp((caddr_t)ea->arp_sha, LLADDR(sdl), sdl->sdl_alen)) 489 log(LOG_INFO, "arp info overwritten for %08x by %s\n", 490 ntohl(isaddr.s_addr), ether_sprintf(ea->arp_sha)); 491 bcopy((caddr_t)ea->arp_sha, LLADDR(sdl), 492 sdl->sdl_alen = sizeof(ea->arp_sha)); 493 if (rt->rt_expire) 494 rt->rt_expire = time.tv_sec + arpt_keep; 495 rt->rt_flags &= ~RTF_REJECT; 496 la->la_asked = 0; 497 if (la->la_hold) { 498 (*ac->ac_if.if_output)(&ac->ac_if, la->la_hold, 499 rt_key(rt), rt); 500 la->la_hold = 0; 501 } 502 } 503 reply: 504 if (op != ARPOP_REQUEST) { 505 out: 506 m_freem(m); 507 return; 508 } 509 if (itaddr.s_addr == myaddr.s_addr) { 510 /* I am the target */ 511 bcopy((caddr_t)ea->arp_sha, (caddr_t)ea->arp_tha, 512 sizeof(ea->arp_sha)); 513 bcopy((caddr_t)ac->ac_enaddr, (caddr_t)ea->arp_sha, 514 sizeof(ea->arp_sha)); 515 } else { 516 la = arplookup(itaddr.s_addr, 0, SIN_PROXY); 517 if (la == 0) 518 goto out; 519 rt = la->la_rt; 520 bcopy((caddr_t)ea->arp_sha, (caddr_t)ea->arp_tha, 521 sizeof(ea->arp_sha)); 522 sdl = SDL(rt->rt_gateway); 523 bcopy(LLADDR(sdl), (caddr_t)ea->arp_sha, sizeof(ea->arp_sha)); 524 } 525 526 bcopy((caddr_t)ea->arp_spa, (caddr_t)ea->arp_tpa, sizeof(ea->arp_spa)); 527 bcopy((caddr_t)&itaddr, (caddr_t)ea->arp_spa, sizeof(ea->arp_spa)); 528 ea->arp_op = htons(ARPOP_REPLY); 529 ea->arp_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 530 eh = (struct ether_header *)sa.sa_data; 531 bcopy((caddr_t)ea->arp_tha, (caddr_t)eh->ether_dhost, 532 sizeof(eh->ether_dhost)); 533 eh->ether_type = htons(ETHERTYPE_ARP); 534 sa.sa_family = AF_UNSPEC; 535 sa.sa_len = sizeof(sa); 536 (*ac->ac_if.if_output)(&ac->ac_if, m, &sa, (struct rtentry *)0); 537 return; 538 } 539 540 /* 541 * Free an arp entry. 542 */ 543 static void 544 arptfree(la) 545 register struct llinfo_arp *la; 546 { 547 register struct rtentry *rt = la->la_rt; 548 register struct sockaddr_dl *sdl; 549 550 if (rt == 0) 551 panic("arptfree"); 552 if (rt->rt_refcnt > 0 && (sdl = SDL(rt->rt_gateway)) && 553 sdl->sdl_family == AF_LINK) { 554 sdl->sdl_alen = 0; 555 la->la_asked = 0; 556 rt->rt_flags &= ~RTF_REJECT; 557 return; 558 } 559 rtrequest(RTM_DELETE, rt_key(rt), (struct sockaddr *)0, rt_mask(rt), 560 0, (struct rtentry **)0); 561 } 562 563 /* 564 * Lookup or enter a new address in arptab. 565 */ 566 static struct llinfo_arp * 567 arplookup(addr, create, proxy) 568 u_int32_t addr; 569 int create, proxy; 570 { 571 register struct rtentry *rt; 572 static struct sockaddr_inarp sin; 573 574 sin.sin_len = sizeof(sin); 575 sin.sin_family = AF_INET; 576 sin.sin_addr.s_addr = addr; 577 sin.sin_other = proxy ? SIN_PROXY : 0; 578 rt = rtalloc1(sintosa(&sin), create); 579 if (rt == 0) 580 return (0); 581 rt->rt_refcnt--; 582 if ((rt->rt_flags & RTF_GATEWAY) || (rt->rt_flags & RTF_LLINFO) == 0 || 583 rt->rt_gateway->sa_family != AF_LINK) { 584 if (create) 585 log(LOG_DEBUG, "arplookup: unable to enter address for %x\n", ntohl(addr)); 586 return (0); 587 } 588 return ((struct llinfo_arp *)rt->rt_llinfo); 589 } 590 591 int 592 arpioctl(cmd, data) 593 u_long cmd; 594 caddr_t data; 595 { 596 597 return (EOPNOTSUPP); 598 } 599 600 void 601 arp_ifinit(ac, ifa) 602 struct arpcom *ac; 603 struct ifaddr *ifa; 604 { 605 606 /* Warn the user if another station has this IP address. */ 607 arprequest(ac, 608 &(IA_SIN(ifa)->sin_addr.s_addr), 609 &(IA_SIN(ifa)->sin_addr.s_addr), 610 ac->ac_enaddr); 611 ifa->ifa_rtrequest = arp_rtrequest; 612 ifa->ifa_flags |= RTF_CLONING; 613 } 614 615 /* 616 * Called from 10 Mb/s Ethernet interrupt handlers 617 * when ether packet type ETHERTYPE_REVARP 618 * is received. Common length and type checks are done here, 619 * then the protocol-specific routine is called. 620 */ 621 void 622 revarpinput(m) 623 struct mbuf *m; 624 { 625 struct arphdr *ar; 626 627 if (m->m_len < sizeof(struct arphdr)) 628 goto out; 629 ar = mtod(m, struct arphdr *); 630 if (ntohs(ar->ar_hrd) != ARPHRD_ETHER) 631 goto out; 632 if (m->m_len < sizeof(struct arphdr) + 2 * (ar->ar_hln + ar->ar_pln)) 633 goto out; 634 switch (ntohs(ar->ar_pro)) { 635 636 case ETHERTYPE_IP: 637 case ETHERTYPE_IPTRAILERS: 638 in_revarpinput(m); 639 return; 640 641 default: 642 break; 643 } 644 out: 645 m_freem(m); 646 } 647 648 /* 649 * RARP for Internet protocols on 10 Mb/s Ethernet. 650 * Algorithm is that given in RFC 903. 651 * We are only using for bootstrap purposes to get an ip address for one of 652 * our interfaces. Thus we support no user-interface. 653 * 654 * Since the contents of the RARP reply are specific to the interface that 655 * sent the request, this code must ensure that they are properly associated. 656 * 657 * Note: also supports ARP via RARP packets, per the RFC. 658 */ 659 void 660 in_revarpinput(m) 661 struct mbuf *m; 662 { 663 struct ifnet *ifp; 664 struct ether_arp *ar; 665 int op; 666 667 ar = mtod(m, struct ether_arp *); 668 op = ntohs(ar->arp_op); 669 switch (op) { 670 case ARPOP_REQUEST: 671 case ARPOP_REPLY: /* per RFC */ 672 in_arpinput(m); 673 return; 674 case ARPOP_REVREPLY: 675 break; 676 case ARPOP_REVREQUEST: /* handled by rarpd(8) */ 677 default: 678 goto out; 679 } 680 if (!revarp_in_progress) 681 goto out; 682 ifp = m->m_pkthdr.rcvif; 683 if (ifp != myip_ifp) /* !same interface */ 684 goto out; 685 if (myip_initialized) 686 goto wake; 687 if (bcmp(ar->arp_tha, ((struct arpcom *)ifp)->ac_enaddr, 688 sizeof(ar->arp_tha))) 689 goto out; 690 bcopy((caddr_t)ar->arp_spa, (caddr_t)&srv_ip, sizeof(srv_ip)); 691 bcopy((caddr_t)ar->arp_tpa, (caddr_t)&myip, sizeof(myip)); 692 myip_initialized = 1; 693 wake: /* Do wakeup every time in case it was missed. */ 694 wakeup((caddr_t)&myip); 695 696 out: 697 m_freem(m); 698 } 699 700 /* 701 * Send a RARP request for the ip address of the specified interface. 702 * The request should be RFC 903-compliant. 703 */ 704 void 705 revarprequest(ifp) 706 struct ifnet *ifp; 707 { 708 struct sockaddr sa; 709 struct mbuf *m; 710 struct ether_header *eh; 711 struct ether_arp *ea; 712 struct arpcom *ac = (struct arpcom *)ifp; 713 714 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 715 return; 716 m->m_len = sizeof(*ea); 717 m->m_pkthdr.len = sizeof(*ea); 718 MH_ALIGN(m, sizeof(*ea)); 719 ea = mtod(m, struct ether_arp *); 720 eh = (struct ether_header *)sa.sa_data; 721 bzero((caddr_t)ea, sizeof(*ea)); 722 bcopy((caddr_t)etherbroadcastaddr, (caddr_t)eh->ether_dhost, 723 sizeof(eh->ether_dhost)); 724 eh->ether_type = htons(ETHERTYPE_REVARP); 725 ea->arp_hrd = htons(ARPHRD_ETHER); 726 ea->arp_pro = htons(ETHERTYPE_IP); 727 ea->arp_hln = sizeof(ea->arp_sha); /* hardware address length */ 728 ea->arp_pln = sizeof(ea->arp_spa); /* protocol address length */ 729 ea->arp_op = htons(ARPOP_REVREQUEST); 730 bcopy((caddr_t)ac->ac_enaddr, (caddr_t)ea->arp_sha, 731 sizeof(ea->arp_sha)); 732 bcopy((caddr_t)ac->ac_enaddr, (caddr_t)ea->arp_tha, 733 sizeof(ea->arp_tha)); 734 sa.sa_family = AF_UNSPEC; 735 sa.sa_len = sizeof(sa); 736 ifp->if_output(ifp, m, &sa, (struct rtentry *)0); 737 } 738 739 /* 740 * RARP for the ip address of the specified interface, but also 741 * save the ip address of the server that sent the answer. 742 * Timeout if no response is received. 743 */ 744 int 745 revarpwhoarewe(ifp, serv_in, clnt_in) 746 struct ifnet *ifp; 747 struct in_addr *serv_in; 748 struct in_addr *clnt_in; 749 { 750 int result, count = 20; 751 752 if (myip_initialized) 753 return EIO; 754 755 myip_ifp = ifp; 756 revarp_in_progress = 1; 757 while (count--) { 758 revarprequest(ifp); 759 result = tsleep((caddr_t)&myip, PSOCK, "revarp", hz/2); 760 if (result != EWOULDBLOCK) 761 break; 762 } 763 revarp_in_progress = 0; 764 if (!myip_initialized) 765 return ENETUNREACH; 766 767 bcopy((caddr_t)&srv_ip, serv_in, sizeof(*serv_in)); 768 bcopy((caddr_t)&myip, clnt_in, sizeof(*clnt_in)); 769 return 0; 770 } 771 772 /* For compatibility: only saves interface address. */ 773 int 774 revarpwhoami(in, ifp) 775 struct in_addr *in; 776 struct ifnet *ifp; 777 { 778 struct in_addr server; 779 return (revarpwhoarewe(ifp, &server, in)); 780 } 781 782 783 #ifdef DDB 784 785 #include <machine/db_machdep.h> 786 #include <ddb/db_interface.h> 787 #include <ddb/db_output.h> 788 static void 789 db_print_sa(sa) 790 struct sockaddr *sa; 791 { 792 int len; 793 u_char *p; 794 795 if (sa == 0) { 796 db_printf("[NULL]"); 797 return; 798 } 799 800 p = (u_char*)sa; 801 len = sa->sa_len; 802 db_printf("["); 803 while (len > 0) { 804 db_printf("%d", *p); 805 p++; len--; 806 if (len) db_printf(","); 807 } 808 db_printf("]\n"); 809 } 810 static void 811 db_print_ifa(ifa) 812 struct ifaddr *ifa; 813 { 814 if (ifa == 0) 815 return; 816 db_printf(" ifa_addr="); 817 db_print_sa(ifa->ifa_addr); 818 db_printf(" ifa_dsta="); 819 db_print_sa(ifa->ifa_dstaddr); 820 db_printf(" ifa_mask="); 821 db_print_sa(ifa->ifa_netmask); 822 db_printf(" flags=0x%x,refcnt=%d,metric=%d\n", 823 ifa->ifa_flags, 824 ifa->ifa_refcnt, 825 ifa->ifa_metric); 826 } 827 static void 828 db_print_llinfo(li) 829 caddr_t li; 830 { 831 struct llinfo_arp *la; 832 833 if (li == 0) 834 return; 835 la = (struct llinfo_arp *)li; 836 db_printf(" la_rt=%p la_hold=%p, la_asked=0x%lx\n", 837 la->la_rt, la->la_hold, la->la_asked); 838 } 839 /* 840 * Function to pass to rn_walktree(). 841 * Return non-zero error to abort walk. 842 */ 843 static int 844 db_show_radix_node(rn, w) 845 struct radix_node *rn; 846 void *w; 847 { 848 struct rtentry *rt = (struct rtentry *)rn; 849 850 db_printf("rtentry=%p", rt); 851 852 db_printf(" flags=0x%x refcnt=%d use=%ld expire=%ld\n", 853 rt->rt_flags, rt->rt_refcnt, 854 rt->rt_use, rt->rt_expire); 855 856 db_printf(" key="); db_print_sa(rt_key(rt)); 857 db_printf(" mask="); db_print_sa(rt_mask(rt)); 858 db_printf(" gw="); db_print_sa(rt->rt_gateway); 859 860 db_printf(" ifp=%p ", rt->rt_ifp); 861 if (rt->rt_ifp) 862 db_printf("(%s)", rt->rt_ifp->if_xname); 863 else 864 db_printf("(NULL)"); 865 866 db_printf(" ifa=%p\n", rt->rt_ifa); 867 db_print_ifa(rt->rt_ifa); 868 869 db_printf(" genmask="); db_print_sa(rt->rt_genmask); 870 871 db_printf(" gwroute=%p llinfo=%p\n", 872 rt->rt_gwroute, rt->rt_llinfo); 873 db_print_llinfo(rt->rt_llinfo); 874 875 return (0); 876 } 877 /* 878 * Function to print all the route trees. 879 * Use this from ddb: "call db_show_arptab" 880 */ 881 int 882 db_show_arptab() 883 { 884 struct radix_node_head *rnh; 885 rnh = rt_tables[AF_INET]; 886 db_printf("Route tree for AF_INET\n"); 887 if (rnh == NULL) { 888 db_printf(" (not initialized)\n"); 889 return (0); 890 } 891 rn_walktree(rnh, db_show_radix_node, NULL); 892 return (0); 893 } 894 #endif 895 #endif /* INET */ 896