1 /* $NetBSD: if_arp.c,v 1.19 1995/03/06 19:06:09 glass 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 57 #include <net/if.h> 58 #include <net/if_dl.h> 59 #include <net/route.h> 60 61 #include <netinet/in.h> 62 #include <netinet/in_systm.h> 63 #include <netinet/in_var.h> 64 #include <netinet/ip.h> 65 #include <netinet/if_ether.h> 66 67 #define SIN(s) ((struct sockaddr_in *)s) 68 #define SDL(s) ((struct sockaddr_dl *)s) 69 #define SRP(s) ((struct sockaddr_inarp *)s) 70 71 /* 72 * ARP trailer negotiation. Trailer protocol is not IP specific, 73 * but ARP request/response use IP addresses. 74 */ 75 #define ETHERTYPE_IPTRAILERS ETHERTYPE_TRAIL 76 77 /* timer values */ 78 int arpt_prune = (5*60*1); /* walk list every 5 minutes */ 79 int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */ 80 int arpt_down = 20; /* once declared down, don't send for 20 secs */ 81 #define rt_expire rt_rmx.rmx_expire 82 83 static void arprequest __P((struct arpcom *, u_long *, u_long *, u_char *)); 84 static void arptfree __P((struct llinfo_arp *)); 85 static void arptimer __P((void *)); 86 static struct llinfo_arp *arplookup __P((u_long, int, int)); 87 static void in_arpinput __P((struct mbuf *)); 88 89 extern struct ifnet loif; 90 struct llinfo_arp llinfo_arp = {&llinfo_arp, &llinfo_arp}; 91 struct ifqueue arpintrq = {0, 0, 0, 50}; 92 int arp_inuse, arp_allocated, arp_intimer; 93 int arp_maxtries = 5; 94 int useloopback = 1; /* use loopback interface for local traffic */ 95 int arpinit_done = 0; 96 97 /* revarp state */ 98 static struct in_addr myip, srv_ip; 99 static int myip_initialized = 0; 100 static int revarp_in_progress = 0; 101 static struct ifnet *myip_ifp = NULL; 102 103 /* 104 * Timeout routine. Age arp_tab entries periodically. 105 */ 106 /* ARGSUSED */ 107 static void 108 arptimer(arg) 109 void *arg; 110 { 111 int s = splnet(); 112 register struct llinfo_arp *la = llinfo_arp.la_next; 113 114 timeout(arptimer, NULL, arpt_prune * hz); 115 while (la != &llinfo_arp) { 116 register struct rtentry *rt = la->la_rt; 117 la = la->la_next; 118 if (rt->rt_expire && rt->rt_expire <= time.tv_sec) 119 arptfree(la->la_prev); /* timer has expired; clear */ 120 } 121 splx(s); 122 } 123 124 /* 125 * Parallel to llc_rtrequest. 126 */ 127 void 128 arp_rtrequest(req, rt, sa) 129 int req; 130 register struct rtentry *rt; 131 struct sockaddr *sa; 132 { 133 register struct sockaddr *gate = rt->rt_gateway; 134 register struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo; 135 static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK}; 136 137 if (!arpinit_done) { 138 arpinit_done = 1; 139 /* 140 * We generate expiration times from time.tv_sec 141 * so avoid accidently creating permanent routes. 142 */ 143 if (time.tv_sec == 0) { 144 time.tv_sec++; 145 } 146 timeout(arptimer, (caddr_t)0, hz); 147 } 148 if (rt->rt_flags & RTF_GATEWAY) 149 return; 150 switch (req) { 151 152 case RTM_ADD: 153 /* 154 * XXX: If this is a manually added route to interface 155 * such as older version of routed or gated might provide, 156 * restore cloning bit. 157 */ 158 if ((rt->rt_flags & RTF_HOST) == 0 && 159 SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff) 160 rt->rt_flags |= RTF_CLONING; 161 if (rt->rt_flags & RTF_CLONING) { 162 /* 163 * Case 1: This route should come from a route to iface. 164 */ 165 rt_setgate(rt, rt_key(rt), 166 (struct sockaddr *)&null_sdl); 167 gate = rt->rt_gateway; 168 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 169 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 170 /* 171 * Give this route an expiration time, even though 172 * it's a "permanent" route, so that routes cloned 173 * from it do not need their expiration time set. 174 */ 175 rt->rt_expire = time.tv_sec; 176 break; 177 } 178 /* Announce a new entry if requested. */ 179 if (rt->rt_flags & RTF_ANNOUNCE) 180 arprequest((struct arpcom *)rt->rt_ifp, 181 &SIN(rt_key(rt))->sin_addr.s_addr, 182 &SIN(rt_key(rt))->sin_addr.s_addr, 183 (u_char *)LLADDR(SDL(gate))); 184 /*FALLTHROUGH*/ 185 case RTM_RESOLVE: 186 if (gate->sa_family != AF_LINK || 187 gate->sa_len < sizeof(null_sdl)) { 188 log(LOG_DEBUG, "arp_rtrequest: bad gateway value"); 189 break; 190 } 191 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 192 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 193 if (la != 0) 194 break; /* This happens on a route change */ 195 /* 196 * Case 2: This route may come from cloning, or a manual route 197 * add with a LL address. 198 */ 199 R_Malloc(la, struct llinfo_arp *, sizeof(*la)); 200 rt->rt_llinfo = (caddr_t)la; 201 if (la == 0) { 202 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); 203 break; 204 } 205 arp_inuse++, arp_allocated++; 206 Bzero(la, sizeof(*la)); 207 la->la_rt = rt; 208 rt->rt_flags |= RTF_LLINFO; 209 insque(la, &llinfo_arp); 210 if (SIN(rt_key(rt))->sin_addr.s_addr == 211 (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) { 212 /* 213 * This test used to be 214 * if (loif.if_flags & IFF_UP) 215 * It allowed local traffic to be forced 216 * through the hardware by configuring the loopback down. 217 * However, it causes problems during network configuration 218 * for boards that can't receive packets they send. 219 * It is now necessary to clear "useloopback" and remove 220 * the route to force traffic out to the hardware. 221 */ 222 rt->rt_expire = 0; 223 Bcopy(((struct arpcom *)rt->rt_ifp)->ac_enaddr, 224 LLADDR(SDL(gate)), SDL(gate)->sdl_alen = 6); 225 if (useloopback) 226 rt->rt_ifp = &loif; 227 228 } 229 break; 230 231 case RTM_DELETE: 232 if (la == 0) 233 break; 234 arp_inuse--; 235 remque(la); 236 rt->rt_llinfo = 0; 237 rt->rt_flags &= ~RTF_LLINFO; 238 if (la->la_hold) 239 m_freem(la->la_hold); 240 Free((caddr_t)la); 241 } 242 } 243 244 /* 245 * Broadcast an ARP packet, asking who has addr on interface ac. 246 */ 247 void 248 arpwhohas(ac, addr) 249 register struct arpcom *ac; 250 register struct in_addr *addr; 251 { 252 arprequest(ac, &ac->ac_ipaddr.s_addr, &addr->s_addr, ac->ac_enaddr); 253 } 254 255 /* 256 * Broadcast an ARP request. Caller specifies: 257 * - arp header source ip address 258 * - arp header target ip address 259 * - arp header source ethernet address 260 */ 261 static void 262 arprequest(ac, sip, tip, enaddr) 263 register struct arpcom *ac; 264 register u_long *sip, *tip; 265 register u_char *enaddr; 266 { 267 register struct mbuf *m; 268 register struct ether_header *eh; 269 register struct ether_arp *ea; 270 struct sockaddr sa; 271 272 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 273 return; 274 m->m_len = sizeof(*ea); 275 m->m_pkthdr.len = sizeof(*ea); 276 MH_ALIGN(m, sizeof(*ea)); 277 ea = mtod(m, struct ether_arp *); 278 eh = (struct ether_header *)sa.sa_data; 279 bzero((caddr_t)ea, sizeof (*ea)); 280 bcopy((caddr_t)etherbroadcastaddr, (caddr_t)eh->ether_dhost, 281 sizeof(eh->ether_dhost)); 282 eh->ether_type = htons(ETHERTYPE_ARP); 283 ea->arp_hrd = htons(ARPHRD_ETHER); 284 ea->arp_pro = htons(ETHERTYPE_IP); 285 ea->arp_hln = sizeof(ea->arp_sha); /* hardware address length */ 286 ea->arp_pln = sizeof(ea->arp_spa); /* protocol address length */ 287 ea->arp_op = htons(ARPOP_REQUEST); 288 bcopy((caddr_t)enaddr, (caddr_t)ea->arp_sha, sizeof(ea->arp_sha)); 289 bcopy((caddr_t)sip, (caddr_t)ea->arp_spa, sizeof(ea->arp_spa)); 290 bcopy((caddr_t)tip, (caddr_t)ea->arp_tpa, sizeof(ea->arp_tpa)); 291 sa.sa_family = AF_UNSPEC; 292 sa.sa_len = sizeof(sa); 293 (*ac->ac_if.if_output)(&ac->ac_if, m, &sa, (struct rtentry *)0); 294 } 295 296 /* 297 * Resolve an IP address into an ethernet address. If success, 298 * desten is filled in. If there is no entry in arptab, 299 * set one up and broadcast a request for the IP address. 300 * Hold onto this mbuf and resend it once the address 301 * is finally resolved. A return value of 1 indicates 302 * that desten has been filled in and the packet should be sent 303 * normally; a 0 return indicates that the packet has been 304 * taken over here, either now or for later transmission. 305 */ 306 int 307 arpresolve(ac, rt, m, dst, desten) 308 register struct arpcom *ac; 309 register struct rtentry *rt; 310 struct mbuf *m; 311 register struct sockaddr *dst; 312 register u_char *desten; 313 { 314 register struct llinfo_arp *la; 315 struct sockaddr_dl *sdl; 316 317 if (m->m_flags & M_BCAST) { /* broadcast */ 318 bcopy((caddr_t)etherbroadcastaddr, (caddr_t)desten, 319 sizeof(etherbroadcastaddr)); 320 return (1); 321 } 322 if (m->m_flags & M_MCAST) { /* multicast */ 323 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); 324 return(1); 325 } 326 if (rt) 327 la = (struct llinfo_arp *)rt->rt_llinfo; 328 else { 329 if (la = arplookup(SIN(dst)->sin_addr.s_addr, 1, 0)) 330 rt = la->la_rt; 331 } 332 if (la == 0 || rt == 0) { 333 log(LOG_DEBUG, "arpresolve: can't allocate llinfo"); 334 m_freem(m); 335 return (0); 336 } 337 sdl = SDL(rt->rt_gateway); 338 /* 339 * Check the address family and length is valid, the address 340 * is resolved; otherwise, try to resolve. 341 */ 342 if ((rt->rt_expire == 0 || rt->rt_expire > time.tv_sec) && 343 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 344 bcopy(LLADDR(sdl), desten, sdl->sdl_alen); 345 return 1; 346 } 347 /* 348 * There is an arptab entry, but no ethernet address 349 * response yet. Replace the held mbuf with this 350 * latest one. 351 */ 352 if (la->la_hold) 353 m_freem(la->la_hold); 354 la->la_hold = m; 355 /* 356 * Re-send the ARP request when appropriate. 357 */ 358 #ifdef DIAGNOSTIC 359 if (rt->rt_expire == 0) { 360 /* This should never happen. (Should it? -gwr) */ 361 printf("arpresolve: unresolved and rt_expire == 0\n"); 362 /* Set expiration time to now (expired). */ 363 rt->rt_expire = time.tv_sec; 364 } 365 #endif 366 if (rt->rt_expire) { 367 rt->rt_flags &= ~RTF_REJECT; 368 if (la->la_asked == 0 || rt->rt_expire != time.tv_sec) { 369 rt->rt_expire = time.tv_sec; 370 if (la->la_asked++ < arp_maxtries) 371 arpwhohas(ac, &(SIN(dst)->sin_addr)); 372 else { 373 rt->rt_flags |= RTF_REJECT; 374 rt->rt_expire += arpt_down; 375 la->la_asked = 0; 376 } 377 } 378 } 379 return (0); 380 } 381 382 /* 383 * Common length and type checks are done here, 384 * then the protocol-specific routine is called. 385 */ 386 void 387 arpintr() 388 { 389 register struct mbuf *m; 390 register struct arphdr *ar; 391 int s; 392 393 while (arpintrq.ifq_head) { 394 s = splimp(); 395 IF_DEQUEUE(&arpintrq, m); 396 splx(s); 397 if (m == 0 || (m->m_flags & M_PKTHDR) == 0) 398 panic("arpintr"); 399 if (m->m_len >= sizeof(struct arphdr) && 400 (ar = mtod(m, struct arphdr *)) && 401 ntohs(ar->ar_hrd) == ARPHRD_ETHER && 402 m->m_len >= 403 sizeof(struct arphdr) + 2 * (ar->ar_hln + ar->ar_pln)) 404 switch (ntohs(ar->ar_pro)) { 405 406 case ETHERTYPE_IP: 407 case ETHERTYPE_IPTRAILERS: 408 in_arpinput(m); 409 continue; 410 } 411 m_freem(m); 412 } 413 } 414 415 /* 416 * ARP for Internet protocols on 10 Mb/s Ethernet. 417 * Algorithm is that given in RFC 826. 418 * In addition, a sanity check is performed on the sender 419 * protocol address, to catch impersonators. 420 * We no longer handle negotiations for use of trailer protocol: 421 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 422 * along with IP replies if we wanted trailers sent to us, 423 * and also sent them in response to IP replies. 424 * This allowed either end to announce the desire to receive 425 * trailer packets. 426 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 427 * but formerly didn't normally send requests. 428 */ 429 static void 430 in_arpinput(m) 431 struct mbuf *m; 432 { 433 register struct ether_arp *ea; 434 register struct arpcom *ac = (struct arpcom *)m->m_pkthdr.rcvif; 435 struct ether_header *eh; 436 register struct llinfo_arp *la = 0; 437 register struct rtentry *rt; 438 struct in_ifaddr *ia, *maybe_ia = 0; 439 struct sockaddr_dl *sdl; 440 struct sockaddr sa; 441 struct in_addr isaddr, itaddr, myaddr; 442 int op; 443 444 ea = mtod(m, struct ether_arp *); 445 op = ntohs(ea->arp_op); 446 bcopy((caddr_t)ea->arp_spa, (caddr_t)&isaddr, sizeof (isaddr)); 447 bcopy((caddr_t)ea->arp_tpa, (caddr_t)&itaddr, sizeof (itaddr)); 448 for (ia = in_ifaddr; ia; ia = ia->ia_next) 449 if (ia->ia_ifp == &ac->ac_if) { 450 maybe_ia = ia; 451 if ((itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) || 452 (isaddr.s_addr == ia->ia_addr.sin_addr.s_addr)) 453 break; 454 } 455 if (maybe_ia == 0) 456 goto out; 457 myaddr = ia ? ia->ia_addr.sin_addr : maybe_ia->ia_addr.sin_addr; 458 if (!bcmp((caddr_t)ea->arp_sha, (caddr_t)ac->ac_enaddr, 459 sizeof (ea->arp_sha))) 460 goto out; /* it's from me, ignore it. */ 461 if (!bcmp((caddr_t)ea->arp_sha, (caddr_t)etherbroadcastaddr, 462 sizeof (ea->arp_sha))) { 463 log(LOG_ERR, 464 "arp: ether address is broadcast for IP address %x!\n", 465 ntohl(isaddr.s_addr)); 466 goto out; 467 } 468 if (isaddr.s_addr == myaddr.s_addr) { 469 log(LOG_ERR, 470 "duplicate IP address %08x sent from ethernet address %s\n", 471 ntohl(isaddr.s_addr), ether_sprintf(ea->arp_sha)); 472 itaddr = myaddr; 473 goto reply; 474 } 475 la = arplookup(isaddr.s_addr, itaddr.s_addr == myaddr.s_addr, 0); 476 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { 477 if (sdl->sdl_alen && 478 bcmp((caddr_t)ea->arp_sha, LLADDR(sdl), sdl->sdl_alen)) 479 log(LOG_INFO, "arp info overwritten for %08x by %s\n", 480 ntohl(isaddr.s_addr), ether_sprintf(ea->arp_sha)); 481 bcopy((caddr_t)ea->arp_sha, LLADDR(sdl), 482 sdl->sdl_alen = sizeof(ea->arp_sha)); 483 if (rt->rt_expire) 484 rt->rt_expire = time.tv_sec + arpt_keep; 485 rt->rt_flags &= ~RTF_REJECT; 486 la->la_asked = 0; 487 if (la->la_hold) { 488 (*ac->ac_if.if_output)(&ac->ac_if, la->la_hold, 489 rt_key(rt), rt); 490 la->la_hold = 0; 491 } 492 } 493 reply: 494 if (op != ARPOP_REQUEST) { 495 out: 496 m_freem(m); 497 return; 498 } 499 if (itaddr.s_addr == myaddr.s_addr) { 500 /* I am the target */ 501 bcopy((caddr_t)ea->arp_sha, (caddr_t)ea->arp_tha, 502 sizeof(ea->arp_sha)); 503 bcopy((caddr_t)ac->ac_enaddr, (caddr_t)ea->arp_sha, 504 sizeof(ea->arp_sha)); 505 } else { 506 la = arplookup(itaddr.s_addr, 0, SIN_PROXY); 507 if (la == 0) 508 goto out; 509 rt = la->la_rt; 510 bcopy((caddr_t)ea->arp_sha, (caddr_t)ea->arp_tha, 511 sizeof(ea->arp_sha)); 512 sdl = SDL(rt->rt_gateway); 513 bcopy(LLADDR(sdl), (caddr_t)ea->arp_sha, sizeof(ea->arp_sha)); 514 } 515 516 bcopy((caddr_t)ea->arp_spa, (caddr_t)ea->arp_tpa, sizeof(ea->arp_spa)); 517 bcopy((caddr_t)&itaddr, (caddr_t)ea->arp_spa, sizeof(ea->arp_spa)); 518 ea->arp_op = htons(ARPOP_REPLY); 519 ea->arp_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 520 eh = (struct ether_header *)sa.sa_data; 521 bcopy((caddr_t)ea->arp_tha, (caddr_t)eh->ether_dhost, 522 sizeof(eh->ether_dhost)); 523 eh->ether_type = htons(ETHERTYPE_ARP); 524 sa.sa_family = AF_UNSPEC; 525 sa.sa_len = sizeof(sa); 526 (*ac->ac_if.if_output)(&ac->ac_if, m, &sa, (struct rtentry *)0); 527 return; 528 } 529 530 /* 531 * Free an arp entry. 532 */ 533 static void 534 arptfree(la) 535 register struct llinfo_arp *la; 536 { 537 register struct rtentry *rt = la->la_rt; 538 register struct sockaddr_dl *sdl; 539 540 if (rt == 0) 541 panic("arptfree"); 542 if (rt->rt_refcnt > 0 && (sdl = SDL(rt->rt_gateway)) && 543 sdl->sdl_family == AF_LINK) { 544 sdl->sdl_alen = 0; 545 la->la_asked = 0; 546 rt->rt_flags &= ~RTF_REJECT; 547 return; 548 } 549 rtrequest(RTM_DELETE, rt_key(rt), (struct sockaddr *)0, rt_mask(rt), 550 0, (struct rtentry **)0); 551 } 552 553 /* 554 * Lookup or enter a new address in arptab. 555 */ 556 static struct llinfo_arp * 557 arplookup(addr, create, proxy) 558 u_long addr; 559 int create, proxy; 560 { 561 register struct rtentry *rt; 562 static struct sockaddr_inarp sin; 563 564 sin.sin_len = sizeof(sin); 565 sin.sin_family = AF_INET; 566 sin.sin_addr.s_addr = addr; 567 sin.sin_other = proxy ? SIN_PROXY : 0; 568 rt = rtalloc1((struct sockaddr *)&sin, create); 569 if (rt == 0) 570 return (0); 571 rt->rt_refcnt--; 572 if ((rt->rt_flags & RTF_GATEWAY) || (rt->rt_flags & RTF_LLINFO) == 0 || 573 rt->rt_gateway->sa_family != AF_LINK) { 574 if (create) 575 log(LOG_DEBUG, "arplookup: unable to enter address for %x\n", ntohl(addr)); 576 return (0); 577 } 578 return ((struct llinfo_arp *)rt->rt_llinfo); 579 } 580 581 int 582 arpioctl(cmd, data) 583 int cmd; 584 caddr_t data; 585 { 586 return (EOPNOTSUPP); 587 } 588 589 /* 590 * Called from 10 Mb/s Ethernet interrupt handlers 591 * when ether packet type ETHERTYPE_REVARP 592 * is received. Common length and type checks are done here, 593 * then the protocol-specific routine is called. 594 */ 595 void 596 revarpinput(m) 597 struct mbuf *m; 598 { 599 struct arphdr *ar; 600 int op, s; 601 602 if (m->m_len < sizeof(struct arphdr)) 603 goto out; 604 ar = mtod(m, struct arphdr *); 605 if (ntohs(ar->ar_hrd) != ARPHRD_ETHER) 606 goto out; 607 if (m->m_len < sizeof(struct arphdr) + 2 * (ar->ar_hln + ar->ar_pln)) 608 goto out; 609 switch (ntohs(ar->ar_pro)) { 610 611 case ETHERTYPE_IP: 612 case ETHERTYPE_IPTRAILERS: 613 in_revarpinput(m); 614 return; 615 616 default: 617 break; 618 } 619 out: 620 m_freem(m); 621 } 622 623 /* 624 * RARP for Internet protocols on 10 Mb/s Ethernet. 625 * Algorithm is that given in RFC 903. 626 * We are only using for bootstrap purposes to get an ip address for one of 627 * our interfaces. Thus we support no user-interface. 628 * 629 * Since the contents of the RARP reply are specific to the interface that 630 * sent the request, this code must ensure that they are properly associated. 631 * 632 * Note: also supports ARP via RARP packets, per the RFC. 633 */ 634 in_revarpinput(m) 635 struct mbuf *m; 636 { 637 struct ifnet *ifp; 638 struct ether_arp *ar; 639 int op, s; 640 641 ar = mtod(m, struct ether_arp *); 642 op = ntohs(ar->arp_op); 643 switch (op) { 644 case ARPOP_REQUEST: 645 case ARPOP_REPLY: /* per RFC */ 646 in_arpinput(m); 647 return; 648 case ARPOP_REVREPLY: 649 break; 650 case ARPOP_REVREQUEST: /* handled by rarpd(8) */ 651 default: 652 goto out; 653 } 654 if (!revarp_in_progress) 655 goto out; 656 ifp = m->m_pkthdr.rcvif; 657 if (ifp != myip_ifp) /* !same interface */ 658 goto out; 659 if (myip_initialized) 660 goto wake; 661 if (bcmp(ar->arp_tha, ((struct arpcom *)ifp)->ac_enaddr, 662 sizeof(ar->arp_tha))) 663 goto out; 664 bcopy((caddr_t)ar->arp_spa, (caddr_t)&srv_ip, sizeof(srv_ip)); 665 bcopy((caddr_t)ar->arp_tpa, (caddr_t)&myip, sizeof(myip)); 666 myip_initialized = 1; 667 wake: /* Do wakeup every time in case it was missed. */ 668 wakeup((caddr_t)&myip); 669 670 out: 671 m_freem(m); 672 } 673 674 /* 675 * Send a RARP request for the ip address of the specified interface. 676 * The request should be RFC 903-compliant. 677 */ 678 void 679 revarprequest(ifp) 680 struct ifnet *ifp; 681 { 682 struct sockaddr sa; 683 struct mbuf *m; 684 struct ether_header *eh; 685 struct ether_arp *ea; 686 struct arpcom *ac = (struct arpcom *)ifp; 687 688 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 689 return; 690 m->m_len = sizeof(*ea); 691 m->m_pkthdr.len = sizeof(*ea); 692 MH_ALIGN(m, sizeof(*ea)); 693 ea = mtod(m, struct ether_arp *); 694 eh = (struct ether_header *)sa.sa_data; 695 bzero((caddr_t)ea, sizeof(*ea)); 696 bcopy((caddr_t)etherbroadcastaddr, (caddr_t)eh->ether_dhost, 697 sizeof(eh->ether_dhost)); 698 eh->ether_type = htons(ETHERTYPE_REVARP); 699 ea->arp_hrd = htons(ARPHRD_ETHER); 700 ea->arp_pro = htons(ETHERTYPE_IP); 701 ea->arp_hln = sizeof(ea->arp_sha); /* hardware address length */ 702 ea->arp_pln = sizeof(ea->arp_spa); /* protocol address length */ 703 ea->arp_op = htons(ARPOP_REVREQUEST); 704 bcopy((caddr_t)ac->ac_enaddr, (caddr_t)ea->arp_sha, 705 sizeof(ea->arp_sha)); 706 bcopy((caddr_t)ac->ac_enaddr, (caddr_t)ea->arp_tha, 707 sizeof(ea->arp_tha)); 708 sa.sa_family = AF_UNSPEC; 709 sa.sa_len = sizeof(sa); 710 ifp->if_output(ifp, m, &sa, (struct rtentry *)0); 711 } 712 713 /* 714 * RARP for the ip address of the specified interface, but also 715 * save the ip address of the server that sent the answer. 716 * Timeout if no response is received. 717 */ 718 int 719 revarpwhoarewe(ifp, serv_in, clnt_in) 720 struct ifnet *ifp; 721 struct in_addr *serv_in; 722 struct in_addr *clnt_in; 723 { 724 int result, count = 20; 725 726 if (myip_initialized) 727 return EIO; 728 729 myip_ifp = ifp; 730 revarp_in_progress = 1; 731 while (count--) { 732 revarprequest(ifp); 733 result = tsleep((caddr_t)&myip, PSOCK, "revarp", hz/2); 734 if (result != EWOULDBLOCK) 735 break; 736 } 737 revarp_in_progress = 0; 738 if (!myip_initialized) 739 return ENETUNREACH; 740 741 bcopy((caddr_t)&srv_ip, serv_in, sizeof(*serv_in)); 742 bcopy((caddr_t)&myip, clnt_in, sizeof(*clnt_in)); 743 return 0; 744 } 745 746 /* For compatibility: only saves interface address. */ 747 int 748 revarpwhoami(in, ifp) 749 struct in_addr *in; 750 struct ifnet *ifp; 751 { 752 struct in_addr server; 753 return (revarpwhoarewe(ifp, &server, in)); 754 } 755 756 757 #ifdef DDB 758 static void 759 db_print_sa(sa) 760 struct sockaddr *sa; 761 { 762 int len; 763 u_char *p; 764 765 if (sa == 0) { 766 db_printf("[NULL]"); 767 return; 768 } 769 770 p = (u_char*)sa; 771 len = sa->sa_len; 772 db_printf("["); 773 while (len > 0) { 774 db_printf("%d", *p); 775 p++; len--; 776 if (len) db_printf(","); 777 } 778 db_printf("]\n"); 779 } 780 static void 781 db_print_ifa(ifa) 782 struct ifaddr *ifa; 783 { 784 if (ifa == 0) 785 return; 786 db_printf(" ifa_addr="); 787 db_print_sa(ifa->ifa_addr); 788 db_printf(" ifa_dsta="); 789 db_print_sa(ifa->ifa_dstaddr); 790 db_printf(" ifa_mask="); 791 db_print_sa(ifa->ifa_netmask); 792 db_printf(" flags=0x%x,refcnt=%d,metric=%d\n", 793 ifa->ifa_flags, 794 ifa->ifa_refcnt, 795 ifa->ifa_metric); 796 } 797 static void 798 db_print_llinfo(li) 799 caddr_t li; 800 { 801 struct llinfo_arp *la; 802 803 if (li == 0) 804 return; 805 la = (struct llinfo_arp *)li; 806 db_printf(" la_rt=0x%x la_hold=0x%x, la_asked=0x%x\n", 807 la->la_rt, la->la_hold, la->la_asked); 808 } 809 /* 810 * Function to pass to rn_walktree(). 811 * Return non-zero error to abort walk. 812 */ 813 static int 814 db_show_radix_node(rn, w) 815 struct radix_node *rn; 816 void *w; 817 { 818 struct rtentry *rt = (struct rtentry *)rn; 819 820 db_printf("rtentry=0x%x", rt); 821 822 db_printf(" flags=0x%x refcnt=%d use=%d expire=%d\n", 823 rt->rt_flags, rt->rt_refcnt, 824 rt->rt_use, rt->rt_expire); 825 826 db_printf(" key="); db_print_sa(rt_key(rt)); 827 db_printf(" mask="); db_print_sa(rt_mask(rt)); 828 db_printf(" gw="); db_print_sa(rt->rt_gateway); 829 830 db_printf(" ifp=0x%x ", rt->rt_ifp); 831 if (rt->rt_ifp) 832 db_printf("(%s%d)", 833 rt->rt_ifp->if_name, 834 rt->rt_ifp->if_unit); 835 else 836 db_printf("(NULL)"); 837 838 db_printf(" ifa=0x%x\n", rt->rt_ifa); 839 db_print_ifa(rt->rt_ifa); 840 841 db_printf(" genmask="); db_print_sa(rt->rt_genmask); 842 843 db_printf(" gwroute=0x%x llinfo=0x%x\n", 844 rt->rt_gwroute, rt->rt_llinfo); 845 db_print_llinfo(rt->rt_llinfo); 846 847 return (0); 848 } 849 /* 850 * Function to print all the route trees. 851 * Use this from ddb: "call db_show_arptab" 852 */ 853 db_show_arptab() 854 { 855 struct radix_node_head *rnh; 856 rnh = rt_tables[AF_INET]; 857 db_printf("Route tree for AF_INET\n"); 858 if (rnh == NULL) { 859 db_printf(" (not initialized)\n"); 860 return (0); 861 } 862 rn_walktree(rnh, db_show_radix_node, NULL); 863 return (0); 864 } 865 #endif 866 #endif /* INET */ 867