1 /* $NetBSD: if_arp.c,v 1.43 1998/01/05 10:31:44 thorpej 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 8.2 (Berkeley) 9/26/94 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/ethertypes.h> 59 #include <net/if.h> 60 #include <net/if_dl.h> 61 #include <net/route.h> 62 63 #include <netinet/in.h> 64 #include <netinet/in_systm.h> 65 #include <netinet/in_var.h> 66 #include <netinet/ip.h> 67 #include <netinet/if_inarp.h> 68 69 #include "loop.h" 70 71 #define SIN(s) ((struct sockaddr_in *)s) 72 #define SDL(s) ((struct sockaddr_dl *)s) 73 #define SRP(s) ((struct sockaddr_inarp *)s) 74 75 /* 76 * ARP trailer negotiation. Trailer protocol is not IP specific, 77 * but ARP request/response use IP addresses. 78 */ 79 #define ETHERTYPE_IPTRAILERS ETHERTYPE_TRAIL 80 81 /* timer values */ 82 int arpt_prune = (5*60*1); /* walk list every 5 minutes */ 83 int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */ 84 int arpt_down = 20; /* once declared down, don't send for 20 secs */ 85 #define rt_expire rt_rmx.rmx_expire 86 87 static void arprequest __P((struct ifnet *, 88 struct in_addr *, struct in_addr *, u_int8_t *)); 89 static void arptfree __P((struct llinfo_arp *)); 90 static void arptimer __P((void *)); 91 static struct llinfo_arp *arplookup __P((struct in_addr *, int, int)); 92 static void in_arpinput __P((struct mbuf *)); 93 94 extern struct ifnet loif[NLOOP]; 95 LIST_HEAD(, llinfo_arp) llinfo_arp; 96 struct ifqueue arpintrq = {0, 0, 0, 50}; 97 int arp_inuse, arp_allocated, arp_intimer; 98 int arp_maxtries = 5; 99 int useloopback = 1; /* use loopback interface for local traffic */ 100 int arpinit_done = 0; 101 102 /* revarp state */ 103 static struct in_addr myip, srv_ip; 104 static int myip_initialized = 0; 105 static int revarp_in_progress = 0; 106 static struct ifnet *myip_ifp = NULL; 107 108 #ifdef DDB 109 static void db_print_sa __P((struct sockaddr *)); 110 static void db_print_ifa __P((struct ifaddr *)); 111 static void db_print_llinfo __P((caddr_t)); 112 static int db_show_radix_node __P((struct radix_node *, void *)); 113 #endif 114 115 /* 116 * this should be elsewhere. 117 */ 118 119 static char * 120 lla_snprintf __P((u_int8_t *, int)); 121 122 static char * 123 lla_snprintf(adrp, len) 124 u_int8_t *adrp; 125 int len; 126 { 127 static char buf[16*3]; 128 static const char hexdigits[] = { 129 '0','1','2','3','4','5','6','7', 130 '8','9','a','b','c','d','e','f' 131 }; 132 133 int i; 134 char *p; 135 136 p = buf; 137 138 *p++ = hexdigits[(*adrp)>>4]; 139 *p++ = hexdigits[(*adrp++)&0xf]; 140 141 for (i=1; i<len && i<16; i++) { 142 *p++ = ':'; 143 *p++ = hexdigits[(*adrp)>>4]; 144 *p++ = hexdigits[(*adrp++)&0xf]; 145 } 146 147 *p = 0; 148 return buf; 149 } 150 151 /* 152 * Timeout routine. Age arp_tab entries periodically. 153 */ 154 /* ARGSUSED */ 155 static void 156 arptimer(arg) 157 void *arg; 158 { 159 int s; 160 register struct llinfo_arp *la, *nla; 161 162 s = splsoftnet(); 163 timeout(arptimer, NULL, arpt_prune * hz); 164 for (la = llinfo_arp.lh_first; la != 0; la = nla) { 165 register struct rtentry *rt = la->la_rt; 166 167 nla = la->la_list.le_next; 168 if (rt->rt_expire && rt->rt_expire <= time.tv_sec) 169 arptfree(la); /* timer has expired; clear */ 170 } 171 splx(s); 172 } 173 174 /* 175 * Parallel to llc_rtrequest. 176 */ 177 void 178 arp_rtrequest(req, rt, sa) 179 int req; 180 register struct rtentry *rt; 181 struct sockaddr *sa; 182 { 183 register struct sockaddr *gate = rt->rt_gateway; 184 register struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo; 185 static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK}; 186 187 if (!arpinit_done) { 188 arpinit_done = 1; 189 /* 190 * We generate expiration times from time.tv_sec 191 * so avoid accidently creating permanent routes. 192 */ 193 if (time.tv_sec == 0) { 194 time.tv_sec++; 195 } 196 timeout(arptimer, (caddr_t)0, hz); 197 } 198 if (rt->rt_flags & RTF_GATEWAY) 199 return; 200 switch (req) { 201 202 case RTM_ADD: 203 /* 204 * XXX: If this is a manually added route to interface 205 * such as older version of routed or gated might provide, 206 * restore cloning bit. 207 */ 208 if ((rt->rt_flags & RTF_HOST) == 0 && 209 SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff) 210 rt->rt_flags |= RTF_CLONING; 211 if (rt->rt_flags & RTF_CLONING) { 212 /* 213 * Case 1: This route should come from a route to iface. 214 */ 215 rt_setgate(rt, rt_key(rt), 216 (struct sockaddr *)&null_sdl); 217 gate = rt->rt_gateway; 218 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 219 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 220 /* 221 * Give this route an expiration time, even though 222 * it's a "permanent" route, so that routes cloned 223 * from it do not need their expiration time set. 224 */ 225 rt->rt_expire = time.tv_sec; 226 break; 227 } 228 /* Announce a new entry if requested. */ 229 if (rt->rt_flags & RTF_ANNOUNCE) 230 arprequest(rt->rt_ifp, 231 &SIN(rt_key(rt))->sin_addr, 232 &SIN(rt_key(rt))->sin_addr, 233 (u_char *)LLADDR(SDL(gate))); 234 /*FALLTHROUGH*/ 235 case RTM_RESOLVE: 236 if (gate->sa_family != AF_LINK || 237 gate->sa_len < sizeof(null_sdl)) { 238 log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n"); 239 break; 240 } 241 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 242 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 243 if (la != 0) 244 break; /* This happens on a route change */ 245 /* 246 * Case 2: This route may come from cloning, or a manual route 247 * add with a LL address. 248 */ 249 R_Malloc(la, struct llinfo_arp *, sizeof(*la)); 250 rt->rt_llinfo = (caddr_t)la; 251 if (la == 0) { 252 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); 253 break; 254 } 255 arp_inuse++, arp_allocated++; 256 Bzero(la, sizeof(*la)); 257 la->la_rt = rt; 258 rt->rt_flags |= RTF_LLINFO; 259 LIST_INSERT_HEAD(&llinfo_arp, la, la_list); 260 if (in_hosteq(SIN(rt_key(rt))->sin_addr, 261 (IA_SIN(rt->rt_ifa))->sin_addr)) { 262 /* 263 * This test used to be 264 * if (loif.if_flags & IFF_UP) 265 * It allowed local traffic to be forced through 266 * the hardware by configuring the loopback down. 267 * However, it causes problems during network 268 * configuration for boards that can't receive 269 * packets they send. It is now necessary to clear 270 * "useloopback" and remove the route to force 271 * traffic out to the hardware. 272 */ 273 rt->rt_expire = 0; 274 Bcopy(LLADDR(rt->rt_ifp->if_sadl), 275 LLADDR(SDL(gate)), 276 SDL(gate)->sdl_alen = 277 rt->rt_ifp->if_data.ifi_addrlen); 278 if (useloopback) 279 rt->rt_ifp = &loif[0]; 280 } 281 break; 282 283 case RTM_DELETE: 284 if (la == 0) 285 break; 286 arp_inuse--; 287 LIST_REMOVE(la, la_list); 288 rt->rt_llinfo = 0; 289 rt->rt_flags &= ~RTF_LLINFO; 290 if (la->la_hold) 291 m_freem(la->la_hold); 292 Free((caddr_t)la); 293 } 294 } 295 296 /* 297 * Broadcast an ARP request. Caller specifies: 298 * - arp header source ip address 299 * - arp header target ip address 300 * - arp header source ethernet address 301 */ 302 static void 303 arprequest(ifp, sip, tip, enaddr) 304 register struct ifnet *ifp; 305 register struct in_addr *sip, *tip; 306 register u_int8_t *enaddr; 307 { 308 register struct mbuf *m; 309 struct arphdr *ah; 310 struct sockaddr sa; 311 312 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 313 return; 314 m->m_len = sizeof(*ah) + 2*sizeof(struct in_addr) + 315 2*ifp->if_data.ifi_addrlen; 316 m->m_pkthdr.len = m->m_len; 317 MH_ALIGN(m, m->m_len); 318 ah = mtod(m, struct arphdr *); 319 bzero((caddr_t)ah, m->m_len); 320 ah->ar_pro = htons(ETHERTYPE_IP); 321 ah->ar_hln = ifp->if_data.ifi_addrlen; /* hardware address length */ 322 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 323 ah->ar_op = htons(ARPOP_REQUEST); 324 bcopy((caddr_t)enaddr, (caddr_t)ar_sha(ah), ah->ar_hln); 325 bcopy((caddr_t)sip, (caddr_t)ar_spa(ah), ah->ar_pln); 326 bcopy((caddr_t)tip, (caddr_t)ar_tpa(ah), ah->ar_pln); 327 sa.sa_family = AF_ARP; 328 sa.sa_len = 2; 329 m->m_flags |= M_BCAST; 330 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 331 } 332 333 /* 334 * Resolve an IP address into an ethernet address. If success, 335 * desten is filled in. If there is no entry in arptab, 336 * set one up and broadcast a request for the IP address. 337 * Hold onto this mbuf and resend it once the address 338 * is finally resolved. A return value of 1 indicates 339 * that desten has been filled in and the packet should be sent 340 * normally; a 0 return indicates that the packet has been 341 * taken over here, either now or for later transmission. 342 */ 343 int 344 arpresolve(ifp, rt, m, dst, desten) 345 register struct ifnet *ifp; 346 register struct rtentry *rt; 347 struct mbuf *m; 348 register struct sockaddr *dst; 349 register u_char *desten; 350 { 351 register struct llinfo_arp *la; 352 struct sockaddr_dl *sdl; 353 354 if (rt) 355 la = (struct llinfo_arp *)rt->rt_llinfo; 356 else { 357 if ((la = arplookup(&SIN(dst)->sin_addr, 1, 0)) != NULL) 358 rt = la->la_rt; 359 } 360 if (la == 0 || rt == 0) { 361 log(LOG_DEBUG, "arpresolve: can't allocate llinfo\n"); 362 m_freem(m); 363 return (0); 364 } 365 sdl = SDL(rt->rt_gateway); 366 /* 367 * Check the address family and length is valid, the address 368 * is resolved; otherwise, try to resolve. 369 */ 370 if ((rt->rt_expire == 0 || rt->rt_expire > time.tv_sec) && 371 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 372 bcopy(LLADDR(sdl), desten, 373 min(sdl->sdl_alen, ifp->if_data.ifi_addrlen)); 374 return 1; 375 } 376 /* 377 * There is an arptab entry, but no ethernet address 378 * response yet. Replace the held mbuf with this 379 * latest one. 380 */ 381 if (la->la_hold) 382 m_freem(la->la_hold); 383 la->la_hold = m; 384 /* 385 * Re-send the ARP request when appropriate. 386 */ 387 #ifdef DIAGNOSTIC 388 if (rt->rt_expire == 0) { 389 /* This should never happen. (Should it? -gwr) */ 390 printf("arpresolve: unresolved and rt_expire == 0\n"); 391 /* Set expiration time to now (expired). */ 392 rt->rt_expire = time.tv_sec; 393 } 394 #endif 395 if (rt->rt_expire) { 396 rt->rt_flags &= ~RTF_REJECT; 397 if (la->la_asked == 0 || rt->rt_expire != time.tv_sec) { 398 rt->rt_expire = time.tv_sec; 399 if (la->la_asked++ < arp_maxtries) 400 arprequest(ifp, 401 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 402 &SIN(dst)->sin_addr, 403 LLADDR(ifp->if_sadl)); 404 else { 405 rt->rt_flags |= RTF_REJECT; 406 rt->rt_expire += arpt_down; 407 la->la_asked = 0; 408 } 409 } 410 } 411 return (0); 412 } 413 414 /* 415 * Common length and type checks are done here, 416 * then the protocol-specific routine is called. 417 */ 418 void 419 arpintr() 420 { 421 register struct mbuf *m; 422 register struct arphdr *ar; 423 int s; 424 425 while (arpintrq.ifq_head) { 426 s = splimp(); 427 IF_DEQUEUE(&arpintrq, m); 428 splx(s); 429 if (m == 0 || (m->m_flags & M_PKTHDR) == 0) 430 panic("arpintr"); 431 432 if (m->m_len >= sizeof(struct arphdr) && 433 (ar = mtod(m, struct arphdr *)) && 434 /* XXX ntohs(ar->ar_hrd) == ARPHRD_ETHER && */ 435 m->m_len >= 436 sizeof(struct arphdr) + 2 * (ar->ar_hln + ar->ar_pln)) 437 switch (ntohs(ar->ar_pro)) { 438 439 case ETHERTYPE_IP: 440 case ETHERTYPE_IPTRAILERS: 441 in_arpinput(m); 442 continue; 443 } 444 m_freem(m); 445 } 446 } 447 448 /* 449 * ARP for Internet protocols on 10 Mb/s Ethernet. 450 * Algorithm is that given in RFC 826. 451 * In addition, a sanity check is performed on the sender 452 * protocol address, to catch impersonators. 453 * We no longer handle negotiations for use of trailer protocol: 454 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 455 * along with IP replies if we wanted trailers sent to us, 456 * and also sent them in response to IP replies. 457 * This allowed either end to announce the desire to receive 458 * trailer packets. 459 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 460 * but formerly didn't normally send requests. 461 */ 462 static void 463 in_arpinput(m) 464 struct mbuf *m; 465 { 466 struct arphdr *ah; 467 register struct ifnet *ifp = m->m_pkthdr.rcvif; 468 register struct llinfo_arp *la = 0; 469 register struct rtentry *rt; 470 struct in_ifaddr *ia, *maybe_ia = 0; 471 struct sockaddr_dl *sdl; 472 struct sockaddr sa; 473 struct in_addr isaddr, itaddr, myaddr; 474 int op; 475 476 ah = mtod(m, struct arphdr *); 477 op = ntohs(ah->ar_op); 478 bcopy((caddr_t)ar_spa(ah), (caddr_t)&isaddr, sizeof (isaddr)); 479 bcopy((caddr_t)ar_tpa(ah), (caddr_t)&itaddr, sizeof (itaddr)); 480 481 /* 482 * If the target IP address is zero, ignore the packet. 483 * This prevents the code below from tring to answer 484 * when we are using IP address zero (booting). 485 */ 486 if (in_nullhost(itaddr)) 487 goto out; 488 489 /* 490 * If the source IP address is zero, this is most likely a 491 * confused host trying to use IP address zero. (Windoze?) 492 * XXX: Should we bother trying to reply to these? 493 */ 494 if (in_nullhost(isaddr)) 495 goto out; 496 497 /* Search for a matching interface address. */ 498 for (ia = in_ifaddr.tqh_first; ia != 0; ia = ia->ia_list.tqe_next) 499 if (ia->ia_ifp == ifp) { 500 maybe_ia = ia; 501 if (in_hosteq(itaddr, ia->ia_addr.sin_addr) || 502 in_hosteq(isaddr, ia->ia_addr.sin_addr)) 503 break; 504 } 505 if (maybe_ia == 0) 506 goto out; 507 508 myaddr = ia ? ia->ia_addr.sin_addr : maybe_ia->ia_addr.sin_addr; 509 if (!bcmp((caddr_t)ar_sha(ah), LLADDR(ifp->if_sadl), 510 ifp->if_data.ifi_addrlen)) 511 goto out; /* it's from me, ignore it. */ 512 513 if (!bcmp((caddr_t)ar_sha(ah), (caddr_t)ifp->if_broadcastaddr, 514 ifp->if_data.ifi_addrlen)) { 515 log(LOG_ERR, 516 "%s: arp: link address is broadcast for IP address %x!\n", 517 ifp->if_xname, ntohl(isaddr.s_addr)); 518 goto out; 519 } 520 521 if (in_hosteq(isaddr, myaddr)) { 522 log(LOG_ERR, 523 "duplicate IP address %08x sent from link address %s\n", 524 ntohl(isaddr.s_addr), lla_snprintf(ar_sha(ah), ah->ar_hln)); 525 itaddr = myaddr; 526 goto reply; 527 } 528 la = arplookup(&isaddr, in_hosteq(itaddr, myaddr), 0); 529 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { 530 if (sdl->sdl_alen && 531 bcmp((caddr_t)ar_sha(ah), LLADDR(sdl), sdl->sdl_alen)) 532 log(LOG_INFO, "arp info overwritten for %08x by %s\n", 533 ntohl(isaddr.s_addr), 534 lla_snprintf(ar_sha(ah), ah->ar_hln)); 535 /* 536 * sanity check for the address length. 537 * XXX this does not work for protocols with variable address 538 * length. -is 539 */ 540 if (sdl->sdl_alen && 541 sdl->sdl_alen != ah->ar_hln) { 542 log(LOG_WARNING, 543 "arp from %08x: new addr len %d, was %d", 544 ntohl(isaddr.s_addr), ah->ar_hln, sdl->sdl_alen); 545 } 546 if (ifp->if_data.ifi_addrlen != ah->ar_hln) { 547 log(LOG_WARNING, 548 "arp from %08x: addr len: new %d, i/f %d (ignored)", 549 ntohl(isaddr.s_addr), ah->ar_hln, 550 ifp->if_data.ifi_addrlen); 551 goto reply; 552 } 553 bcopy((caddr_t)ar_sha(ah), LLADDR(sdl), 554 sdl->sdl_alen = ah->ar_hln); 555 if (rt->rt_expire) 556 rt->rt_expire = time.tv_sec + arpt_keep; 557 rt->rt_flags &= ~RTF_REJECT; 558 la->la_asked = 0; 559 if (la->la_hold) { 560 (*ifp->if_output)(ifp, la->la_hold, 561 rt_key(rt), rt); 562 la->la_hold = 0; 563 } 564 } 565 reply: 566 if (op != ARPOP_REQUEST) { 567 out: 568 m_freem(m); 569 return; 570 } 571 if (in_hosteq(itaddr, myaddr)) { 572 /* I am the target */ 573 bcopy((caddr_t)ar_sha(ah), (caddr_t)ar_tha(ah), ah->ar_hln); 574 bcopy(LLADDR(ifp->if_sadl), (caddr_t)ar_sha(ah), ah->ar_hln); 575 } else { 576 la = arplookup(&itaddr, 0, SIN_PROXY); 577 if (la == 0) 578 goto out; 579 rt = la->la_rt; 580 bcopy((caddr_t)ar_sha(ah), (caddr_t)ar_tha(ah), ah->ar_hln); 581 sdl = SDL(rt->rt_gateway); 582 bcopy(LLADDR(sdl), (caddr_t)ar_sha(ah), ah->ar_hln); 583 } 584 585 bcopy((caddr_t)ar_spa(ah), (caddr_t)ar_tpa(ah), ah->ar_pln); 586 bcopy((caddr_t)&itaddr, (caddr_t)ar_spa(ah), ah->ar_pln); 587 ah->ar_op = htons(ARPOP_REPLY); 588 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 589 m->m_flags &= ~(M_BCAST|M_MCAST); /* never reply by broadcast */ 590 sa.sa_family = AF_ARP; 591 sa.sa_len = 2; 592 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 593 return; 594 } 595 596 /* 597 * Free an arp entry. 598 */ 599 static void 600 arptfree(la) 601 register struct llinfo_arp *la; 602 { 603 register struct rtentry *rt = la->la_rt; 604 register struct sockaddr_dl *sdl; 605 606 if (rt == 0) 607 panic("arptfree"); 608 if (rt->rt_refcnt > 0 && (sdl = SDL(rt->rt_gateway)) && 609 sdl->sdl_family == AF_LINK) { 610 sdl->sdl_alen = 0; 611 la->la_asked = 0; 612 rt->rt_flags &= ~RTF_REJECT; 613 return; 614 } 615 rtrequest(RTM_DELETE, rt_key(rt), (struct sockaddr *)0, rt_mask(rt), 616 0, (struct rtentry **)0); 617 } 618 619 /* 620 * Lookup or enter a new address in arptab. 621 */ 622 static struct llinfo_arp * 623 arplookup(addr, create, proxy) 624 struct in_addr *addr; 625 int create, proxy; 626 { 627 register struct rtentry *rt; 628 static struct sockaddr_inarp sin; 629 630 sin.sin_len = sizeof(sin); 631 sin.sin_family = AF_INET; 632 sin.sin_addr = *addr; 633 sin.sin_other = proxy ? SIN_PROXY : 0; 634 rt = rtalloc1(sintosa(&sin), create); 635 if (rt == 0) 636 return (0); 637 rt->rt_refcnt--; 638 if ((rt->rt_flags & RTF_GATEWAY) || (rt->rt_flags & RTF_LLINFO) == 0 || 639 rt->rt_gateway->sa_family != AF_LINK) { 640 if (create) 641 log(LOG_DEBUG, "arplookup: unable to enter address for %x\n", 642 ntohl(addr->s_addr)); 643 return (0); 644 } 645 return ((struct llinfo_arp *)rt->rt_llinfo); 646 } 647 648 int 649 arpioctl(cmd, data) 650 u_long cmd; 651 caddr_t data; 652 { 653 654 return (EOPNOTSUPP); 655 } 656 657 void 658 arp_ifinit(ifp, ifa) 659 struct ifnet *ifp; 660 struct ifaddr *ifa; 661 { 662 struct in_addr *ip; 663 664 /* 665 * Warn the user if another station has this IP address, 666 * but only if the interface IP address is not zero. 667 */ 668 ip = &IA_SIN(ifa)->sin_addr; 669 if (!in_nullhost(*ip)) 670 arprequest(ifp, ip, ip, LLADDR(ifp->if_sadl)); 671 672 ifa->ifa_rtrequest = arp_rtrequest; 673 ifa->ifa_flags |= RTF_CLONING; 674 } 675 676 /* 677 * Called from 10 Mb/s Ethernet interrupt handlers 678 * when ether packet type ETHERTYPE_REVARP 679 * is received. Common length and type checks are done here, 680 * then the protocol-specific routine is called. 681 */ 682 void 683 revarpinput(m) 684 struct mbuf *m; 685 { 686 struct arphdr *ar; 687 688 if (m->m_len < sizeof(struct arphdr)) 689 goto out; 690 ar = mtod(m, struct arphdr *); 691 #if 0 /* XXX I don't think we need this... and it will prevent other LL */ 692 if (ntohs(ar->ar_hrd) != ARPHRD_ETHER) 693 goto out; 694 #endif 695 if (m->m_len < sizeof(struct arphdr) + 2 * (ar->ar_hln + ar->ar_pln)) 696 goto out; 697 switch (ntohs(ar->ar_pro)) { 698 699 case ETHERTYPE_IP: 700 case ETHERTYPE_IPTRAILERS: 701 in_revarpinput(m); 702 return; 703 704 default: 705 break; 706 } 707 out: 708 m_freem(m); 709 } 710 711 /* 712 * RARP for Internet protocols on 10 Mb/s Ethernet. 713 * Algorithm is that given in RFC 903. 714 * We are only using for bootstrap purposes to get an ip address for one of 715 * our interfaces. Thus we support no user-interface. 716 * 717 * Since the contents of the RARP reply are specific to the interface that 718 * sent the request, this code must ensure that they are properly associated. 719 * 720 * Note: also supports ARP via RARP packets, per the RFC. 721 */ 722 void 723 in_revarpinput(m) 724 struct mbuf *m; 725 { 726 struct ifnet *ifp; 727 struct arphdr *ah; 728 int op; 729 730 ah = mtod(m, struct arphdr *); 731 op = ntohs(ah->ar_op); 732 switch (op) { 733 case ARPOP_REQUEST: 734 case ARPOP_REPLY: /* per RFC */ 735 in_arpinput(m); 736 return; 737 case ARPOP_REVREPLY: 738 break; 739 case ARPOP_REVREQUEST: /* handled by rarpd(8) */ 740 default: 741 goto out; 742 } 743 if (!revarp_in_progress) 744 goto out; 745 ifp = m->m_pkthdr.rcvif; 746 if (ifp != myip_ifp) /* !same interface */ 747 goto out; 748 if (myip_initialized) 749 goto wake; 750 if (bcmp(ar_tha(ah), LLADDR(ifp->if_sadl), ifp->if_sadl->sdl_alen)) 751 goto out; 752 bcopy((caddr_t)ar_spa(ah), (caddr_t)&srv_ip, sizeof(srv_ip)); 753 bcopy((caddr_t)ar_tpa(ah), (caddr_t)&myip, sizeof(myip)); 754 myip_initialized = 1; 755 wake: /* Do wakeup every time in case it was missed. */ 756 wakeup((caddr_t)&myip); 757 758 out: 759 m_freem(m); 760 } 761 762 /* 763 * Send a RARP request for the ip address of the specified interface. 764 * The request should be RFC 903-compliant. 765 */ 766 void 767 revarprequest(ifp) 768 struct ifnet *ifp; 769 { 770 struct sockaddr sa; 771 struct mbuf *m; 772 struct arphdr *ah; 773 774 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 775 return; 776 m->m_len = sizeof(*ah) + 2*sizeof(struct in_addr) + 777 2*ifp->if_data.ifi_addrlen; 778 m->m_pkthdr.len = m->m_len; 779 MH_ALIGN(m, m->m_len); 780 ah = mtod(m, struct arphdr *); 781 bzero((caddr_t)ah, m->m_len); 782 ah->ar_pro = htons(ETHERTYPE_IP); 783 ah->ar_hln = ifp->if_data.ifi_addrlen; /* hardware address length */ 784 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 785 ah->ar_op = htons(ARPOP_REVREQUEST); 786 787 bcopy(LLADDR(ifp->if_sadl), (caddr_t)ar_sha(ah), ah->ar_hln); 788 bcopy(LLADDR(ifp->if_sadl), (caddr_t)ar_tha(ah), ah->ar_hln); 789 790 sa.sa_family = AF_ARP; 791 sa.sa_len = 2; 792 m->m_flags |= M_BCAST; 793 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 794 795 } 796 797 /* 798 * RARP for the ip address of the specified interface, but also 799 * save the ip address of the server that sent the answer. 800 * Timeout if no response is received. 801 */ 802 int 803 revarpwhoarewe(ifp, serv_in, clnt_in) 804 struct ifnet *ifp; 805 struct in_addr *serv_in; 806 struct in_addr *clnt_in; 807 { 808 int result, count = 20; 809 810 if (!myip_initialized) { 811 myip_ifp = ifp; 812 revarp_in_progress = 1; 813 while (count--) { 814 revarprequest(ifp); 815 result = tsleep((caddr_t)&myip, PSOCK, "revarp", hz/2); 816 if (result != EWOULDBLOCK) 817 break; 818 } 819 revarp_in_progress = 0; 820 } 821 if (!myip_initialized) 822 return ENETUNREACH; 823 824 bcopy((caddr_t)&srv_ip, serv_in, sizeof(*serv_in)); 825 bcopy((caddr_t)&myip, clnt_in, sizeof(*clnt_in)); 826 return 0; 827 } 828 829 /* For compatibility: only saves interface address. */ 830 int 831 revarpwhoami(in, ifp) 832 struct in_addr *in; 833 struct ifnet *ifp; 834 { 835 struct in_addr server; 836 return (revarpwhoarewe(ifp, &server, in)); 837 } 838 839 840 #ifdef DDB 841 842 #include <machine/db_machdep.h> 843 #include <ddb/db_interface.h> 844 #include <ddb/db_output.h> 845 static void 846 db_print_sa(sa) 847 struct sockaddr *sa; 848 { 849 int len; 850 u_char *p; 851 852 if (sa == 0) { 853 db_printf("[NULL]"); 854 return; 855 } 856 857 p = (u_char*)sa; 858 len = sa->sa_len; 859 db_printf("["); 860 while (len > 0) { 861 db_printf("%d", *p); 862 p++; len--; 863 if (len) db_printf(","); 864 } 865 db_printf("]\n"); 866 } 867 static void 868 db_print_ifa(ifa) 869 struct ifaddr *ifa; 870 { 871 if (ifa == 0) 872 return; 873 db_printf(" ifa_addr="); 874 db_print_sa(ifa->ifa_addr); 875 db_printf(" ifa_dsta="); 876 db_print_sa(ifa->ifa_dstaddr); 877 db_printf(" ifa_mask="); 878 db_print_sa(ifa->ifa_netmask); 879 db_printf(" flags=0x%x,refcnt=%d,metric=%d\n", 880 ifa->ifa_flags, 881 ifa->ifa_refcnt, 882 ifa->ifa_metric); 883 } 884 static void 885 db_print_llinfo(li) 886 caddr_t li; 887 { 888 struct llinfo_arp *la; 889 890 if (li == 0) 891 return; 892 la = (struct llinfo_arp *)li; 893 db_printf(" la_rt=%p la_hold=%p, la_asked=0x%lx\n", 894 la->la_rt, la->la_hold, la->la_asked); 895 } 896 /* 897 * Function to pass to rn_walktree(). 898 * Return non-zero error to abort walk. 899 */ 900 static int 901 db_show_radix_node(rn, w) 902 struct radix_node *rn; 903 void *w; 904 { 905 struct rtentry *rt = (struct rtentry *)rn; 906 907 db_printf("rtentry=%p", rt); 908 909 db_printf(" flags=0x%x refcnt=%d use=%ld expire=%ld\n", 910 rt->rt_flags, rt->rt_refcnt, 911 rt->rt_use, rt->rt_expire); 912 913 db_printf(" key="); db_print_sa(rt_key(rt)); 914 db_printf(" mask="); db_print_sa(rt_mask(rt)); 915 db_printf(" gw="); db_print_sa(rt->rt_gateway); 916 917 db_printf(" ifp=%p ", rt->rt_ifp); 918 if (rt->rt_ifp) 919 db_printf("(%s)", rt->rt_ifp->if_xname); 920 else 921 db_printf("(NULL)"); 922 923 db_printf(" ifa=%p\n", rt->rt_ifa); 924 db_print_ifa(rt->rt_ifa); 925 926 db_printf(" genmask="); db_print_sa(rt->rt_genmask); 927 928 db_printf(" gwroute=%p llinfo=%p\n", 929 rt->rt_gwroute, rt->rt_llinfo); 930 db_print_llinfo(rt->rt_llinfo); 931 932 return (0); 933 } 934 /* 935 * Function to print all the route trees. 936 * Use this from ddb: "call db_show_arptab" 937 */ 938 int 939 db_show_arptab() 940 { 941 struct radix_node_head *rnh; 942 rnh = rt_tables[AF_INET]; 943 db_printf("Route tree for AF_INET\n"); 944 if (rnh == NULL) { 945 db_printf(" (not initialized)\n"); 946 return (0); 947 } 948 rn_walktree(rnh, db_show_radix_node, NULL); 949 return (0); 950 } 951 #endif 952 #endif /* INET */ 953