1 /* $NetBSD: if_arp.c,v 1.54 1998/12/19 02:46:12 thorpej Exp $ */ 2 3 /*- 4 * Copyright (c) 1998 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. All advertising materials mentioning features or use of this software 53 * must display the following acknowledgement: 54 * This product includes software developed by the University of 55 * California, Berkeley and its contributors. 56 * 4. Neither the name of the University nor the names of its contributors 57 * may be used to endorse or promote products derived from this software 58 * without specific prior written permission. 59 * 60 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 61 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 62 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 63 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 64 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 65 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 66 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 67 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 68 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 69 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 70 * SUCH DAMAGE. 71 * 72 * @(#)if_ether.c 8.2 (Berkeley) 9/26/94 73 */ 74 75 /* 76 * Ethernet address resolution protocol. 77 * TODO: 78 * add "inuse/lock" bit (or ref. count) along with valid bit 79 */ 80 81 #include "opt_ddb.h" 82 #include "opt_inet.h" 83 84 #ifdef INET 85 86 #include <sys/param.h> 87 #include <sys/systm.h> 88 #include <sys/malloc.h> 89 #include <sys/mbuf.h> 90 #include <sys/socket.h> 91 #include <sys/time.h> 92 #include <sys/kernel.h> 93 #include <sys/errno.h> 94 #include <sys/ioctl.h> 95 #include <sys/syslog.h> 96 #include <sys/proc.h> 97 98 #include <net/ethertypes.h> 99 #include <net/if.h> 100 #include <net/if_dl.h> 101 #include <net/route.h> 102 103 #include <netinet/in.h> 104 #include <netinet/in_systm.h> 105 #include <netinet/in_var.h> 106 #include <netinet/ip.h> 107 #include <netinet/if_inarp.h> 108 109 #include "loop.h" 110 111 #define SIN(s) ((struct sockaddr_in *)s) 112 #define SDL(s) ((struct sockaddr_dl *)s) 113 #define SRP(s) ((struct sockaddr_inarp *)s) 114 115 /* 116 * ARP trailer negotiation. Trailer protocol is not IP specific, 117 * but ARP request/response use IP addresses. 118 */ 119 #define ETHERTYPE_IPTRAILERS ETHERTYPE_TRAIL 120 121 /* timer values */ 122 int arpt_prune = (5*60*1); /* walk list every 5 minutes */ 123 int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */ 124 int arpt_down = 20; /* once declared down, don't send for 20 secs */ 125 #define rt_expire rt_rmx.rmx_expire 126 127 static void arprequest __P((struct ifnet *, 128 struct in_addr *, struct in_addr *, u_int8_t *)); 129 static void arptfree __P((struct llinfo_arp *)); 130 static void arptimer __P((void *)); 131 static struct llinfo_arp *arplookup __P((struct in_addr *, int, int)); 132 static void in_arpinput __P((struct mbuf *)); 133 134 extern struct ifnet loif[NLOOP]; 135 LIST_HEAD(, llinfo_arp) llinfo_arp; 136 struct ifqueue arpintrq = {0, 0, 0, 50}; 137 int arp_inuse, arp_allocated, arp_intimer; 138 int arp_maxtries = 5; 139 int useloopback = 1; /* use loopback interface for local traffic */ 140 int arpinit_done = 0; 141 142 /* revarp state */ 143 static struct in_addr myip, srv_ip; 144 static int myip_initialized = 0; 145 static int revarp_in_progress = 0; 146 static struct ifnet *myip_ifp = NULL; 147 148 #ifdef DDB 149 static void db_print_sa __P((struct sockaddr *)); 150 static void db_print_ifa __P((struct ifaddr *)); 151 static void db_print_llinfo __P((caddr_t)); 152 static int db_show_radix_node __P((struct radix_node *, void *)); 153 #endif 154 155 /* 156 * this should be elsewhere. 157 */ 158 159 static char * 160 lla_snprintf __P((u_int8_t *, int)); 161 162 static char * 163 lla_snprintf(adrp, len) 164 u_int8_t *adrp; 165 int len; 166 { 167 static char buf[16*3]; 168 static const char hexdigits[] = { 169 '0','1','2','3','4','5','6','7', 170 '8','9','a','b','c','d','e','f' 171 }; 172 173 int i; 174 char *p; 175 176 p = buf; 177 178 *p++ = hexdigits[(*adrp)>>4]; 179 *p++ = hexdigits[(*adrp++)&0xf]; 180 181 for (i=1; i<len && i<16; i++) { 182 *p++ = ':'; 183 *p++ = hexdigits[(*adrp)>>4]; 184 *p++ = hexdigits[(*adrp++)&0xf]; 185 } 186 187 *p = 0; 188 return buf; 189 } 190 191 /* 192 * Timeout routine. Age arp_tab entries periodically. 193 */ 194 /* ARGSUSED */ 195 static void 196 arptimer(arg) 197 void *arg; 198 { 199 int s; 200 register struct llinfo_arp *la, *nla; 201 202 s = splsoftnet(); 203 timeout(arptimer, NULL, arpt_prune * hz); 204 for (la = llinfo_arp.lh_first; la != 0; la = nla) { 205 register struct rtentry *rt = la->la_rt; 206 207 nla = la->la_list.le_next; 208 if (rt->rt_expire && rt->rt_expire <= time.tv_sec) 209 arptfree(la); /* timer has expired; clear */ 210 } 211 splx(s); 212 } 213 214 /* 215 * Parallel to llc_rtrequest. 216 */ 217 void 218 arp_rtrequest(req, rt, sa) 219 int req; 220 register struct rtentry *rt; 221 struct sockaddr *sa; 222 { 223 register struct sockaddr *gate = rt->rt_gateway; 224 register struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo; 225 static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK}; 226 227 if (!arpinit_done) { 228 arpinit_done = 1; 229 /* 230 * We generate expiration times from time.tv_sec 231 * so avoid accidently creating permanent routes. 232 */ 233 if (time.tv_sec == 0) { 234 time.tv_sec++; 235 } 236 timeout(arptimer, (caddr_t)0, hz); 237 } 238 if (rt->rt_flags & RTF_GATEWAY) 239 return; 240 switch (req) { 241 242 case RTM_ADD: 243 /* 244 * XXX: If this is a manually added route to interface 245 * such as older version of routed or gated might provide, 246 * restore cloning bit. 247 */ 248 if ((rt->rt_flags & RTF_HOST) == 0 && 249 SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff) 250 rt->rt_flags |= RTF_CLONING; 251 if (rt->rt_flags & RTF_CLONING) { 252 /* 253 * Case 1: This route should come from a route to iface. 254 */ 255 rt_setgate(rt, rt_key(rt), 256 (struct sockaddr *)&null_sdl); 257 gate = rt->rt_gateway; 258 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 259 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 260 /* 261 * Give this route an expiration time, even though 262 * it's a "permanent" route, so that routes cloned 263 * from it do not need their expiration time set. 264 */ 265 rt->rt_expire = time.tv_sec; 266 break; 267 } 268 /* Announce a new entry if requested. */ 269 if (rt->rt_flags & RTF_ANNOUNCE) 270 arprequest(rt->rt_ifp, 271 &SIN(rt_key(rt))->sin_addr, 272 &SIN(rt_key(rt))->sin_addr, 273 (u_char *)LLADDR(SDL(gate))); 274 /*FALLTHROUGH*/ 275 case RTM_RESOLVE: 276 if (gate->sa_family != AF_LINK || 277 gate->sa_len < sizeof(null_sdl)) { 278 log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n"); 279 break; 280 } 281 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 282 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 283 if (la != 0) 284 break; /* This happens on a route change */ 285 /* 286 * Case 2: This route may come from cloning, or a manual route 287 * add with a LL address. 288 */ 289 R_Malloc(la, struct llinfo_arp *, sizeof(*la)); 290 rt->rt_llinfo = (caddr_t)la; 291 if (la == 0) { 292 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); 293 break; 294 } 295 arp_inuse++, arp_allocated++; 296 Bzero(la, sizeof(*la)); 297 la->la_rt = rt; 298 rt->rt_flags |= RTF_LLINFO; 299 LIST_INSERT_HEAD(&llinfo_arp, la, la_list); 300 if (in_hosteq(SIN(rt_key(rt))->sin_addr, 301 (IA_SIN(rt->rt_ifa))->sin_addr)) { 302 /* 303 * This test used to be 304 * if (loif.if_flags & IFF_UP) 305 * It allowed local traffic to be forced through 306 * the hardware by configuring the loopback down. 307 * However, it causes problems during network 308 * configuration for boards that can't receive 309 * packets they send. It is now necessary to clear 310 * "useloopback" and remove the route to force 311 * traffic out to the hardware. 312 */ 313 rt->rt_expire = 0; 314 Bcopy(LLADDR(rt->rt_ifp->if_sadl), 315 LLADDR(SDL(gate)), 316 SDL(gate)->sdl_alen = 317 rt->rt_ifp->if_data.ifi_addrlen); 318 if (useloopback) 319 rt->rt_ifp = &loif[0]; 320 } 321 break; 322 323 case RTM_DELETE: 324 if (la == 0) 325 break; 326 arp_inuse--; 327 LIST_REMOVE(la, la_list); 328 rt->rt_llinfo = 0; 329 rt->rt_flags &= ~RTF_LLINFO; 330 if (la->la_hold) 331 m_freem(la->la_hold); 332 Free((caddr_t)la); 333 } 334 } 335 336 /* 337 * Broadcast an ARP request. Caller specifies: 338 * - arp header source ip address 339 * - arp header target ip address 340 * - arp header source ethernet address 341 */ 342 static void 343 arprequest(ifp, sip, tip, enaddr) 344 register struct ifnet *ifp; 345 register struct in_addr *sip, *tip; 346 register u_int8_t *enaddr; 347 { 348 register struct mbuf *m; 349 struct arphdr *ah; 350 struct sockaddr sa; 351 352 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 353 return; 354 m->m_len = sizeof(*ah) + 2*sizeof(struct in_addr) + 355 2*ifp->if_data.ifi_addrlen; 356 m->m_pkthdr.len = m->m_len; 357 MH_ALIGN(m, m->m_len); 358 ah = mtod(m, struct arphdr *); 359 bzero((caddr_t)ah, m->m_len); 360 ah->ar_pro = htons(ETHERTYPE_IP); 361 ah->ar_hln = ifp->if_data.ifi_addrlen; /* hardware address length */ 362 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 363 ah->ar_op = htons(ARPOP_REQUEST); 364 bcopy((caddr_t)enaddr, (caddr_t)ar_sha(ah), ah->ar_hln); 365 bcopy((caddr_t)sip, (caddr_t)ar_spa(ah), ah->ar_pln); 366 bcopy((caddr_t)tip, (caddr_t)ar_tpa(ah), ah->ar_pln); 367 sa.sa_family = AF_ARP; 368 sa.sa_len = 2; 369 m->m_flags |= M_BCAST; 370 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 371 } 372 373 /* 374 * Resolve an IP address into an ethernet address. If success, 375 * desten is filled in. If there is no entry in arptab, 376 * set one up and broadcast a request for the IP address. 377 * Hold onto this mbuf and resend it once the address 378 * is finally resolved. A return value of 1 indicates 379 * that desten has been filled in and the packet should be sent 380 * normally; a 0 return indicates that the packet has been 381 * taken over here, either now or for later transmission. 382 */ 383 int 384 arpresolve(ifp, rt, m, dst, desten) 385 register struct ifnet *ifp; 386 register struct rtentry *rt; 387 struct mbuf *m; 388 register struct sockaddr *dst; 389 register u_char *desten; 390 { 391 register struct llinfo_arp *la; 392 struct sockaddr_dl *sdl; 393 394 if (rt) 395 la = (struct llinfo_arp *)rt->rt_llinfo; 396 else { 397 if ((la = arplookup(&SIN(dst)->sin_addr, 1, 0)) != NULL) 398 rt = la->la_rt; 399 } 400 if (la == 0 || rt == 0) { 401 log(LOG_DEBUG, "arpresolve: can't allocate llinfo\n"); 402 m_freem(m); 403 return (0); 404 } 405 sdl = SDL(rt->rt_gateway); 406 /* 407 * Check the address family and length is valid, the address 408 * is resolved; otherwise, try to resolve. 409 */ 410 if ((rt->rt_expire == 0 || rt->rt_expire > time.tv_sec) && 411 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 412 bcopy(LLADDR(sdl), desten, 413 min(sdl->sdl_alen, ifp->if_data.ifi_addrlen)); 414 return 1; 415 } 416 /* 417 * There is an arptab entry, but no ethernet address 418 * response yet. Replace the held mbuf with this 419 * latest one. 420 */ 421 if (la->la_hold) 422 m_freem(la->la_hold); 423 la->la_hold = m; 424 /* 425 * Re-send the ARP request when appropriate. 426 */ 427 #ifdef DIAGNOSTIC 428 if (rt->rt_expire == 0) { 429 /* This should never happen. (Should it? -gwr) */ 430 printf("arpresolve: unresolved and rt_expire == 0\n"); 431 /* Set expiration time to now (expired). */ 432 rt->rt_expire = time.tv_sec; 433 } 434 #endif 435 if (rt->rt_expire) { 436 rt->rt_flags &= ~RTF_REJECT; 437 if (la->la_asked == 0 || rt->rt_expire != time.tv_sec) { 438 rt->rt_expire = time.tv_sec; 439 if (la->la_asked++ < arp_maxtries) 440 arprequest(ifp, 441 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 442 &SIN(dst)->sin_addr, 443 LLADDR(ifp->if_sadl)); 444 else { 445 rt->rt_flags |= RTF_REJECT; 446 rt->rt_expire += arpt_down; 447 la->la_asked = 0; 448 } 449 } 450 } 451 return (0); 452 } 453 454 /* 455 * Common length and type checks are done here, 456 * then the protocol-specific routine is called. 457 */ 458 void 459 arpintr() 460 { 461 register struct mbuf *m; 462 register struct arphdr *ar; 463 int s; 464 465 while (arpintrq.ifq_head) { 466 s = splimp(); 467 IF_DEQUEUE(&arpintrq, m); 468 splx(s); 469 if (m == 0 || (m->m_flags & M_PKTHDR) == 0) 470 panic("arpintr"); 471 472 if (m->m_len >= sizeof(struct arphdr) && 473 (ar = mtod(m, struct arphdr *)) && 474 /* XXX ntohs(ar->ar_hrd) == ARPHRD_ETHER && */ 475 m->m_len >= 476 sizeof(struct arphdr) + 2 * (ar->ar_hln + ar->ar_pln)) 477 switch (ntohs(ar->ar_pro)) { 478 479 case ETHERTYPE_IP: 480 case ETHERTYPE_IPTRAILERS: 481 in_arpinput(m); 482 continue; 483 } 484 m_freem(m); 485 } 486 } 487 488 /* 489 * ARP for Internet protocols on 10 Mb/s Ethernet. 490 * Algorithm is that given in RFC 826. 491 * In addition, a sanity check is performed on the sender 492 * protocol address, to catch impersonators. 493 * We no longer handle negotiations for use of trailer protocol: 494 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 495 * along with IP replies if we wanted trailers sent to us, 496 * and also sent them in response to IP replies. 497 * This allowed either end to announce the desire to receive 498 * trailer packets. 499 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 500 * but formerly didn't normally send requests. 501 */ 502 static void 503 in_arpinput(m) 504 struct mbuf *m; 505 { 506 struct arphdr *ah; 507 register struct ifnet *ifp = m->m_pkthdr.rcvif; 508 register struct llinfo_arp *la = 0; 509 register struct rtentry *rt; 510 struct in_ifaddr *ia; 511 struct sockaddr_dl *sdl; 512 struct sockaddr sa; 513 struct in_addr isaddr, itaddr, myaddr; 514 int op; 515 516 ah = mtod(m, struct arphdr *); 517 op = ntohs(ah->ar_op); 518 bcopy((caddr_t)ar_spa(ah), (caddr_t)&isaddr, sizeof (isaddr)); 519 bcopy((caddr_t)ar_tpa(ah), (caddr_t)&itaddr, sizeof (itaddr)); 520 521 /* 522 * If the target IP address is zero, ignore the packet. 523 * This prevents the code below from tring to answer 524 * when we are using IP address zero (booting). 525 */ 526 if (in_nullhost(itaddr)) 527 goto out; 528 529 /* 530 * If the source IP address is zero, this is most likely a 531 * confused host trying to use IP address zero. (Windoze?) 532 * XXX: Should we bother trying to reply to these? 533 */ 534 if (in_nullhost(isaddr)) 535 goto out; 536 537 /* 538 * Search for a matching interface address 539 * or any address on the interface to use 540 * as a dummy address in the rest of this function 541 */ 542 INADDR_TO_IA(itaddr, ia); 543 while ((ia != NULL) && ia->ia_ifp != m->m_pkthdr.rcvif) 544 NEXT_IA_WITH_SAME_ADDR(ia); 545 546 if (ia == NULL) { 547 INADDR_TO_IA(isaddr, ia); 548 while ((ia != NULL) && ia->ia_ifp != m->m_pkthdr.rcvif) 549 NEXT_IA_WITH_SAME_ADDR(ia); 550 551 if (ia == NULL) { 552 IFP_TO_IA(ifp, ia); 553 if (ia == NULL) 554 goto out; 555 } 556 } 557 558 myaddr = ia->ia_addr.sin_addr; 559 560 if (!bcmp((caddr_t)ar_sha(ah), LLADDR(ifp->if_sadl), 561 ifp->if_data.ifi_addrlen)) 562 goto out; /* it's from me, ignore it. */ 563 564 if (!bcmp((caddr_t)ar_sha(ah), (caddr_t)ifp->if_broadcastaddr, 565 ifp->if_data.ifi_addrlen)) { 566 log(LOG_ERR, 567 "%s: arp: link address is broadcast for IP address %s!\n", 568 ifp->if_xname, in_fmtaddr(isaddr)); 569 goto out; 570 } 571 572 if (in_hosteq(isaddr, myaddr)) { 573 log(LOG_ERR, 574 "duplicate IP address %s sent from link address %s\n", 575 in_fmtaddr(isaddr), lla_snprintf(ar_sha(ah), ah->ar_hln)); 576 itaddr = myaddr; 577 goto reply; 578 } 579 la = arplookup(&isaddr, in_hosteq(itaddr, myaddr), 0); 580 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { 581 if (sdl->sdl_alen && 582 bcmp((caddr_t)ar_sha(ah), LLADDR(sdl), sdl->sdl_alen)) 583 log(LOG_INFO, "arp info overwritten for %s by %s\n", 584 in_fmtaddr(isaddr), 585 lla_snprintf(ar_sha(ah), ah->ar_hln)); 586 /* 587 * sanity check for the address length. 588 * XXX this does not work for protocols with variable address 589 * length. -is 590 */ 591 if (sdl->sdl_alen && 592 sdl->sdl_alen != ah->ar_hln) { 593 log(LOG_WARNING, 594 "arp from %s: new addr len %d, was %d", 595 in_fmtaddr(isaddr), ah->ar_hln, sdl->sdl_alen); 596 } 597 if (ifp->if_data.ifi_addrlen != ah->ar_hln) { 598 log(LOG_WARNING, 599 "arp from %s: addr len: new %d, i/f %d (ignored)", 600 in_fmtaddr(isaddr), ah->ar_hln, 601 ifp->if_data.ifi_addrlen); 602 goto reply; 603 } 604 bcopy((caddr_t)ar_sha(ah), LLADDR(sdl), 605 sdl->sdl_alen = ah->ar_hln); 606 if (rt->rt_expire) 607 rt->rt_expire = time.tv_sec + arpt_keep; 608 rt->rt_flags &= ~RTF_REJECT; 609 la->la_asked = 0; 610 if (la->la_hold) { 611 (*ifp->if_output)(ifp, la->la_hold, 612 rt_key(rt), rt); 613 la->la_hold = 0; 614 } 615 } 616 reply: 617 if (op != ARPOP_REQUEST) { 618 out: 619 m_freem(m); 620 return; 621 } 622 if (in_hosteq(itaddr, myaddr)) { 623 /* I am the target */ 624 bcopy((caddr_t)ar_sha(ah), (caddr_t)ar_tha(ah), ah->ar_hln); 625 bcopy(LLADDR(ifp->if_sadl), (caddr_t)ar_sha(ah), ah->ar_hln); 626 } else { 627 la = arplookup(&itaddr, 0, SIN_PROXY); 628 if (la == 0) 629 goto out; 630 rt = la->la_rt; 631 bcopy((caddr_t)ar_sha(ah), (caddr_t)ar_tha(ah), ah->ar_hln); 632 sdl = SDL(rt->rt_gateway); 633 bcopy(LLADDR(sdl), (caddr_t)ar_sha(ah), ah->ar_hln); 634 } 635 636 bcopy((caddr_t)ar_spa(ah), (caddr_t)ar_tpa(ah), ah->ar_pln); 637 bcopy((caddr_t)&itaddr, (caddr_t)ar_spa(ah), ah->ar_pln); 638 ah->ar_op = htons(ARPOP_REPLY); 639 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 640 m->m_flags &= ~(M_BCAST|M_MCAST); /* never reply by broadcast */ 641 sa.sa_family = AF_ARP; 642 sa.sa_len = 2; 643 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 644 return; 645 } 646 647 /* 648 * Free an arp entry. 649 */ 650 static void 651 arptfree(la) 652 register struct llinfo_arp *la; 653 { 654 register struct rtentry *rt = la->la_rt; 655 register struct sockaddr_dl *sdl; 656 657 if (rt == 0) 658 panic("arptfree"); 659 if (rt->rt_refcnt > 0 && (sdl = SDL(rt->rt_gateway)) && 660 sdl->sdl_family == AF_LINK) { 661 sdl->sdl_alen = 0; 662 la->la_asked = 0; 663 rt->rt_flags &= ~RTF_REJECT; 664 return; 665 } 666 rtrequest(RTM_DELETE, rt_key(rt), (struct sockaddr *)0, rt_mask(rt), 667 0, (struct rtentry **)0); 668 } 669 670 /* 671 * Lookup or enter a new address in arptab. 672 */ 673 static struct llinfo_arp * 674 arplookup(addr, create, proxy) 675 struct in_addr *addr; 676 int create, proxy; 677 { 678 register struct rtentry *rt; 679 static struct sockaddr_inarp sin; 680 const char *why = 0; 681 682 sin.sin_len = sizeof(sin); 683 sin.sin_family = AF_INET; 684 sin.sin_addr = *addr; 685 sin.sin_other = proxy ? SIN_PROXY : 0; 686 rt = rtalloc1(sintosa(&sin), create); 687 if (rt == 0) 688 return (0); 689 rt->rt_refcnt--; 690 691 if (rt->rt_flags & RTF_GATEWAY) 692 why = "host is not on local network"; 693 else if ((rt->rt_flags & RTF_LLINFO) == 0) 694 why = "could not allocate llinfo"; 695 else if (rt->rt_gateway->sa_family != AF_LINK) 696 why = "gateway route is not ours"; 697 else 698 return ((struct llinfo_arp *)rt->rt_llinfo); 699 700 if (create) 701 log(LOG_DEBUG, "arplookup: unable to enter address" 702 " for %s (%s)\n", 703 in_fmtaddr(*addr), why); 704 return (0); 705 } 706 707 int 708 arpioctl(cmd, data) 709 u_long cmd; 710 caddr_t data; 711 { 712 713 return (EOPNOTSUPP); 714 } 715 716 void 717 arp_ifinit(ifp, ifa) 718 struct ifnet *ifp; 719 struct ifaddr *ifa; 720 { 721 struct in_addr *ip; 722 723 /* 724 * Warn the user if another station has this IP address, 725 * but only if the interface IP address is not zero. 726 */ 727 ip = &IA_SIN(ifa)->sin_addr; 728 if (!in_nullhost(*ip)) 729 arprequest(ifp, ip, ip, LLADDR(ifp->if_sadl)); 730 731 ifa->ifa_rtrequest = arp_rtrequest; 732 ifa->ifa_flags |= RTF_CLONING; 733 } 734 735 /* 736 * Called from 10 Mb/s Ethernet interrupt handlers 737 * when ether packet type ETHERTYPE_REVARP 738 * is received. Common length and type checks are done here, 739 * then the protocol-specific routine is called. 740 */ 741 void 742 revarpinput(m) 743 struct mbuf *m; 744 { 745 struct arphdr *ar; 746 747 if (m->m_len < sizeof(struct arphdr)) 748 goto out; 749 ar = mtod(m, struct arphdr *); 750 #if 0 /* XXX I don't think we need this... and it will prevent other LL */ 751 if (ntohs(ar->ar_hrd) != ARPHRD_ETHER) 752 goto out; 753 #endif 754 if (m->m_len < sizeof(struct arphdr) + 2 * (ar->ar_hln + ar->ar_pln)) 755 goto out; 756 switch (ntohs(ar->ar_pro)) { 757 758 case ETHERTYPE_IP: 759 case ETHERTYPE_IPTRAILERS: 760 in_revarpinput(m); 761 return; 762 763 default: 764 break; 765 } 766 out: 767 m_freem(m); 768 } 769 770 /* 771 * RARP for Internet protocols on 10 Mb/s Ethernet. 772 * Algorithm is that given in RFC 903. 773 * We are only using for bootstrap purposes to get an ip address for one of 774 * our interfaces. Thus we support no user-interface. 775 * 776 * Since the contents of the RARP reply are specific to the interface that 777 * sent the request, this code must ensure that they are properly associated. 778 * 779 * Note: also supports ARP via RARP packets, per the RFC. 780 */ 781 void 782 in_revarpinput(m) 783 struct mbuf *m; 784 { 785 struct ifnet *ifp; 786 struct arphdr *ah; 787 int op; 788 789 ah = mtod(m, struct arphdr *); 790 op = ntohs(ah->ar_op); 791 switch (op) { 792 case ARPOP_REQUEST: 793 case ARPOP_REPLY: /* per RFC */ 794 in_arpinput(m); 795 return; 796 case ARPOP_REVREPLY: 797 break; 798 case ARPOP_REVREQUEST: /* handled by rarpd(8) */ 799 default: 800 goto out; 801 } 802 if (!revarp_in_progress) 803 goto out; 804 ifp = m->m_pkthdr.rcvif; 805 if (ifp != myip_ifp) /* !same interface */ 806 goto out; 807 if (myip_initialized) 808 goto wake; 809 if (bcmp(ar_tha(ah), LLADDR(ifp->if_sadl), ifp->if_sadl->sdl_alen)) 810 goto out; 811 bcopy((caddr_t)ar_spa(ah), (caddr_t)&srv_ip, sizeof(srv_ip)); 812 bcopy((caddr_t)ar_tpa(ah), (caddr_t)&myip, sizeof(myip)); 813 myip_initialized = 1; 814 wake: /* Do wakeup every time in case it was missed. */ 815 wakeup((caddr_t)&myip); 816 817 out: 818 m_freem(m); 819 } 820 821 /* 822 * Send a RARP request for the ip address of the specified interface. 823 * The request should be RFC 903-compliant. 824 */ 825 void 826 revarprequest(ifp) 827 struct ifnet *ifp; 828 { 829 struct sockaddr sa; 830 struct mbuf *m; 831 struct arphdr *ah; 832 833 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 834 return; 835 m->m_len = sizeof(*ah) + 2*sizeof(struct in_addr) + 836 2*ifp->if_data.ifi_addrlen; 837 m->m_pkthdr.len = m->m_len; 838 MH_ALIGN(m, m->m_len); 839 ah = mtod(m, struct arphdr *); 840 bzero((caddr_t)ah, m->m_len); 841 ah->ar_pro = htons(ETHERTYPE_IP); 842 ah->ar_hln = ifp->if_data.ifi_addrlen; /* hardware address length */ 843 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 844 ah->ar_op = htons(ARPOP_REVREQUEST); 845 846 bcopy(LLADDR(ifp->if_sadl), (caddr_t)ar_sha(ah), ah->ar_hln); 847 bcopy(LLADDR(ifp->if_sadl), (caddr_t)ar_tha(ah), ah->ar_hln); 848 849 sa.sa_family = AF_ARP; 850 sa.sa_len = 2; 851 m->m_flags |= M_BCAST; 852 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 853 854 } 855 856 /* 857 * RARP for the ip address of the specified interface, but also 858 * save the ip address of the server that sent the answer. 859 * Timeout if no response is received. 860 */ 861 int 862 revarpwhoarewe(ifp, serv_in, clnt_in) 863 struct ifnet *ifp; 864 struct in_addr *serv_in; 865 struct in_addr *clnt_in; 866 { 867 int result, count = 20; 868 869 if (!myip_initialized) { 870 myip_ifp = ifp; 871 revarp_in_progress = 1; 872 while (count--) { 873 revarprequest(ifp); 874 result = tsleep((caddr_t)&myip, PSOCK, "revarp", hz/2); 875 if (result != EWOULDBLOCK) 876 break; 877 } 878 revarp_in_progress = 0; 879 } 880 if (!myip_initialized) 881 return ENETUNREACH; 882 883 bcopy((caddr_t)&srv_ip, serv_in, sizeof(*serv_in)); 884 bcopy((caddr_t)&myip, clnt_in, sizeof(*clnt_in)); 885 return 0; 886 } 887 888 /* For compatibility: only saves interface address. */ 889 int 890 revarpwhoami(in, ifp) 891 struct in_addr *in; 892 struct ifnet *ifp; 893 { 894 struct in_addr server; 895 return (revarpwhoarewe(ifp, &server, in)); 896 } 897 898 899 #ifdef DDB 900 901 #include <machine/db_machdep.h> 902 #include <ddb/db_interface.h> 903 #include <ddb/db_output.h> 904 static void 905 db_print_sa(sa) 906 struct sockaddr *sa; 907 { 908 int len; 909 u_char *p; 910 911 if (sa == 0) { 912 db_printf("[NULL]"); 913 return; 914 } 915 916 p = (u_char*)sa; 917 len = sa->sa_len; 918 db_printf("["); 919 while (len > 0) { 920 db_printf("%d", *p); 921 p++; len--; 922 if (len) db_printf(","); 923 } 924 db_printf("]\n"); 925 } 926 static void 927 db_print_ifa(ifa) 928 struct ifaddr *ifa; 929 { 930 if (ifa == 0) 931 return; 932 db_printf(" ifa_addr="); 933 db_print_sa(ifa->ifa_addr); 934 db_printf(" ifa_dsta="); 935 db_print_sa(ifa->ifa_dstaddr); 936 db_printf(" ifa_mask="); 937 db_print_sa(ifa->ifa_netmask); 938 db_printf(" flags=0x%x,refcnt=%d,metric=%d\n", 939 ifa->ifa_flags, 940 ifa->ifa_refcnt, 941 ifa->ifa_metric); 942 } 943 static void 944 db_print_llinfo(li) 945 caddr_t li; 946 { 947 struct llinfo_arp *la; 948 949 if (li == 0) 950 return; 951 la = (struct llinfo_arp *)li; 952 db_printf(" la_rt=%p la_hold=%p, la_asked=0x%lx\n", 953 la->la_rt, la->la_hold, la->la_asked); 954 } 955 /* 956 * Function to pass to rn_walktree(). 957 * Return non-zero error to abort walk. 958 */ 959 static int 960 db_show_radix_node(rn, w) 961 struct radix_node *rn; 962 void *w; 963 { 964 struct rtentry *rt = (struct rtentry *)rn; 965 966 db_printf("rtentry=%p", rt); 967 968 db_printf(" flags=0x%x refcnt=%d use=%ld expire=%ld\n", 969 rt->rt_flags, rt->rt_refcnt, 970 rt->rt_use, rt->rt_expire); 971 972 db_printf(" key="); db_print_sa(rt_key(rt)); 973 db_printf(" mask="); db_print_sa(rt_mask(rt)); 974 db_printf(" gw="); db_print_sa(rt->rt_gateway); 975 976 db_printf(" ifp=%p ", rt->rt_ifp); 977 if (rt->rt_ifp) 978 db_printf("(%s)", rt->rt_ifp->if_xname); 979 else 980 db_printf("(NULL)"); 981 982 db_printf(" ifa=%p\n", rt->rt_ifa); 983 db_print_ifa(rt->rt_ifa); 984 985 db_printf(" genmask="); db_print_sa(rt->rt_genmask); 986 987 db_printf(" gwroute=%p llinfo=%p\n", 988 rt->rt_gwroute, rt->rt_llinfo); 989 db_print_llinfo(rt->rt_llinfo); 990 991 return (0); 992 } 993 /* 994 * Function to print all the route trees. 995 * Use this from ddb: "call db_show_arptab" 996 */ 997 int 998 db_show_arptab() 999 { 1000 struct radix_node_head *rnh; 1001 rnh = rt_tables[AF_INET]; 1002 db_printf("Route tree for AF_INET\n"); 1003 if (rnh == NULL) { 1004 db_printf(" (not initialized)\n"); 1005 return (0); 1006 } 1007 rn_walktree(rnh, db_show_radix_node, NULL); 1008 return (0); 1009 } 1010 #endif 1011 #endif /* INET */ 1012