1 /* $NetBSD: if_arp.c,v 1.45 1998/02/15 18:24:23 tls 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 #ifdef INET 82 83 #include <sys/param.h> 84 #include <sys/systm.h> 85 #include <sys/malloc.h> 86 #include <sys/mbuf.h> 87 #include <sys/socket.h> 88 #include <sys/time.h> 89 #include <sys/kernel.h> 90 #include <sys/errno.h> 91 #include <sys/ioctl.h> 92 #include <sys/syslog.h> 93 #include <sys/proc.h> 94 95 #include <net/ethertypes.h> 96 #include <net/if.h> 97 #include <net/if_dl.h> 98 #include <net/route.h> 99 100 #include <netinet/in.h> 101 #include <netinet/in_systm.h> 102 #include <netinet/in_var.h> 103 #include <netinet/ip.h> 104 #include <netinet/if_inarp.h> 105 106 #include "loop.h" 107 108 #define SIN(s) ((struct sockaddr_in *)s) 109 #define SDL(s) ((struct sockaddr_dl *)s) 110 #define SRP(s) ((struct sockaddr_inarp *)s) 111 112 /* 113 * ARP trailer negotiation. Trailer protocol is not IP specific, 114 * but ARP request/response use IP addresses. 115 */ 116 #define ETHERTYPE_IPTRAILERS ETHERTYPE_TRAIL 117 118 /* timer values */ 119 int arpt_prune = (5*60*1); /* walk list every 5 minutes */ 120 int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */ 121 int arpt_down = 20; /* once declared down, don't send for 20 secs */ 122 #define rt_expire rt_rmx.rmx_expire 123 124 static void arprequest __P((struct ifnet *, 125 struct in_addr *, struct in_addr *, u_int8_t *)); 126 static void arptfree __P((struct llinfo_arp *)); 127 static void arptimer __P((void *)); 128 static struct llinfo_arp *arplookup __P((struct in_addr *, int, int)); 129 static void in_arpinput __P((struct mbuf *)); 130 131 extern struct ifnet loif[NLOOP]; 132 LIST_HEAD(, llinfo_arp) llinfo_arp; 133 struct ifqueue arpintrq = {0, 0, 0, 50}; 134 int arp_inuse, arp_allocated, arp_intimer; 135 int arp_maxtries = 5; 136 int useloopback = 1; /* use loopback interface for local traffic */ 137 int arpinit_done = 0; 138 139 /* revarp state */ 140 static struct in_addr myip, srv_ip; 141 static int myip_initialized = 0; 142 static int revarp_in_progress = 0; 143 static struct ifnet *myip_ifp = NULL; 144 145 #ifdef DDB 146 static void db_print_sa __P((struct sockaddr *)); 147 static void db_print_ifa __P((struct ifaddr *)); 148 static void db_print_llinfo __P((caddr_t)); 149 static int db_show_radix_node __P((struct radix_node *, void *)); 150 #endif 151 152 /* 153 * this should be elsewhere. 154 */ 155 156 static char * 157 lla_snprintf __P((u_int8_t *, int)); 158 159 static char * 160 lla_snprintf(adrp, len) 161 u_int8_t *adrp; 162 int len; 163 { 164 static char buf[16*3]; 165 static const char hexdigits[] = { 166 '0','1','2','3','4','5','6','7', 167 '8','9','a','b','c','d','e','f' 168 }; 169 170 int i; 171 char *p; 172 173 p = buf; 174 175 *p++ = hexdigits[(*adrp)>>4]; 176 *p++ = hexdigits[(*adrp++)&0xf]; 177 178 for (i=1; i<len && i<16; i++) { 179 *p++ = ':'; 180 *p++ = hexdigits[(*adrp)>>4]; 181 *p++ = hexdigits[(*adrp++)&0xf]; 182 } 183 184 *p = 0; 185 return buf; 186 } 187 188 /* 189 * Timeout routine. Age arp_tab entries periodically. 190 */ 191 /* ARGSUSED */ 192 static void 193 arptimer(arg) 194 void *arg; 195 { 196 int s; 197 register struct llinfo_arp *la, *nla; 198 199 s = splsoftnet(); 200 timeout(arptimer, NULL, arpt_prune * hz); 201 for (la = llinfo_arp.lh_first; la != 0; la = nla) { 202 register struct rtentry *rt = la->la_rt; 203 204 nla = la->la_list.le_next; 205 if (rt->rt_expire && rt->rt_expire <= time.tv_sec) 206 arptfree(la); /* timer has expired; clear */ 207 } 208 splx(s); 209 } 210 211 /* 212 * Parallel to llc_rtrequest. 213 */ 214 void 215 arp_rtrequest(req, rt, sa) 216 int req; 217 register struct rtentry *rt; 218 struct sockaddr *sa; 219 { 220 register struct sockaddr *gate = rt->rt_gateway; 221 register struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo; 222 static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK}; 223 224 if (!arpinit_done) { 225 arpinit_done = 1; 226 /* 227 * We generate expiration times from time.tv_sec 228 * so avoid accidently creating permanent routes. 229 */ 230 if (time.tv_sec == 0) { 231 time.tv_sec++; 232 } 233 timeout(arptimer, (caddr_t)0, hz); 234 } 235 if (rt->rt_flags & RTF_GATEWAY) 236 return; 237 switch (req) { 238 239 case RTM_ADD: 240 /* 241 * XXX: If this is a manually added route to interface 242 * such as older version of routed or gated might provide, 243 * restore cloning bit. 244 */ 245 if ((rt->rt_flags & RTF_HOST) == 0 && 246 SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff) 247 rt->rt_flags |= RTF_CLONING; 248 if (rt->rt_flags & RTF_CLONING) { 249 /* 250 * Case 1: This route should come from a route to iface. 251 */ 252 rt_setgate(rt, rt_key(rt), 253 (struct sockaddr *)&null_sdl); 254 gate = rt->rt_gateway; 255 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 256 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 257 /* 258 * Give this route an expiration time, even though 259 * it's a "permanent" route, so that routes cloned 260 * from it do not need their expiration time set. 261 */ 262 rt->rt_expire = time.tv_sec; 263 break; 264 } 265 /* Announce a new entry if requested. */ 266 if (rt->rt_flags & RTF_ANNOUNCE) 267 arprequest(rt->rt_ifp, 268 &SIN(rt_key(rt))->sin_addr, 269 &SIN(rt_key(rt))->sin_addr, 270 (u_char *)LLADDR(SDL(gate))); 271 /*FALLTHROUGH*/ 272 case RTM_RESOLVE: 273 if (gate->sa_family != AF_LINK || 274 gate->sa_len < sizeof(null_sdl)) { 275 log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n"); 276 break; 277 } 278 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 279 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 280 if (la != 0) 281 break; /* This happens on a route change */ 282 /* 283 * Case 2: This route may come from cloning, or a manual route 284 * add with a LL address. 285 */ 286 R_Malloc(la, struct llinfo_arp *, sizeof(*la)); 287 rt->rt_llinfo = (caddr_t)la; 288 if (la == 0) { 289 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); 290 break; 291 } 292 arp_inuse++, arp_allocated++; 293 Bzero(la, sizeof(*la)); 294 la->la_rt = rt; 295 rt->rt_flags |= RTF_LLINFO; 296 LIST_INSERT_HEAD(&llinfo_arp, la, la_list); 297 if (in_hosteq(SIN(rt_key(rt))->sin_addr, 298 (IA_SIN(rt->rt_ifa))->sin_addr)) { 299 /* 300 * This test used to be 301 * if (loif.if_flags & IFF_UP) 302 * It allowed local traffic to be forced through 303 * the hardware by configuring the loopback down. 304 * However, it causes problems during network 305 * configuration for boards that can't receive 306 * packets they send. It is now necessary to clear 307 * "useloopback" and remove the route to force 308 * traffic out to the hardware. 309 */ 310 rt->rt_expire = 0; 311 Bcopy(LLADDR(rt->rt_ifp->if_sadl), 312 LLADDR(SDL(gate)), 313 SDL(gate)->sdl_alen = 314 rt->rt_ifp->if_data.ifi_addrlen); 315 if (useloopback) 316 rt->rt_ifp = &loif[0]; 317 } 318 break; 319 320 case RTM_DELETE: 321 if (la == 0) 322 break; 323 arp_inuse--; 324 LIST_REMOVE(la, la_list); 325 rt->rt_llinfo = 0; 326 rt->rt_flags &= ~RTF_LLINFO; 327 if (la->la_hold) 328 m_freem(la->la_hold); 329 Free((caddr_t)la); 330 } 331 } 332 333 /* 334 * Broadcast an ARP request. Caller specifies: 335 * - arp header source ip address 336 * - arp header target ip address 337 * - arp header source ethernet address 338 */ 339 static void 340 arprequest(ifp, sip, tip, enaddr) 341 register struct ifnet *ifp; 342 register struct in_addr *sip, *tip; 343 register u_int8_t *enaddr; 344 { 345 register struct mbuf *m; 346 struct arphdr *ah; 347 struct sockaddr sa; 348 349 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 350 return; 351 m->m_len = sizeof(*ah) + 2*sizeof(struct in_addr) + 352 2*ifp->if_data.ifi_addrlen; 353 m->m_pkthdr.len = m->m_len; 354 MH_ALIGN(m, m->m_len); 355 ah = mtod(m, struct arphdr *); 356 bzero((caddr_t)ah, m->m_len); 357 ah->ar_pro = htons(ETHERTYPE_IP); 358 ah->ar_hln = ifp->if_data.ifi_addrlen; /* hardware address length */ 359 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 360 ah->ar_op = htons(ARPOP_REQUEST); 361 bcopy((caddr_t)enaddr, (caddr_t)ar_sha(ah), ah->ar_hln); 362 bcopy((caddr_t)sip, (caddr_t)ar_spa(ah), ah->ar_pln); 363 bcopy((caddr_t)tip, (caddr_t)ar_tpa(ah), ah->ar_pln); 364 sa.sa_family = AF_ARP; 365 sa.sa_len = 2; 366 m->m_flags |= M_BCAST; 367 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 368 } 369 370 /* 371 * Resolve an IP address into an ethernet address. If success, 372 * desten is filled in. If there is no entry in arptab, 373 * set one up and broadcast a request for the IP address. 374 * Hold onto this mbuf and resend it once the address 375 * is finally resolved. A return value of 1 indicates 376 * that desten has been filled in and the packet should be sent 377 * normally; a 0 return indicates that the packet has been 378 * taken over here, either now or for later transmission. 379 */ 380 int 381 arpresolve(ifp, rt, m, dst, desten) 382 register struct ifnet *ifp; 383 register struct rtentry *rt; 384 struct mbuf *m; 385 register struct sockaddr *dst; 386 register u_char *desten; 387 { 388 register struct llinfo_arp *la; 389 struct sockaddr_dl *sdl; 390 391 if (rt) 392 la = (struct llinfo_arp *)rt->rt_llinfo; 393 else { 394 if ((la = arplookup(&SIN(dst)->sin_addr, 1, 0)) != NULL) 395 rt = la->la_rt; 396 } 397 if (la == 0 || rt == 0) { 398 log(LOG_DEBUG, "arpresolve: can't allocate llinfo\n"); 399 m_freem(m); 400 return (0); 401 } 402 sdl = SDL(rt->rt_gateway); 403 /* 404 * Check the address family and length is valid, the address 405 * is resolved; otherwise, try to resolve. 406 */ 407 if ((rt->rt_expire == 0 || rt->rt_expire > time.tv_sec) && 408 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 409 bcopy(LLADDR(sdl), desten, 410 min(sdl->sdl_alen, ifp->if_data.ifi_addrlen)); 411 return 1; 412 } 413 /* 414 * There is an arptab entry, but no ethernet address 415 * response yet. Replace the held mbuf with this 416 * latest one. 417 */ 418 if (la->la_hold) 419 m_freem(la->la_hold); 420 la->la_hold = m; 421 /* 422 * Re-send the ARP request when appropriate. 423 */ 424 #ifdef DIAGNOSTIC 425 if (rt->rt_expire == 0) { 426 /* This should never happen. (Should it? -gwr) */ 427 printf("arpresolve: unresolved and rt_expire == 0\n"); 428 /* Set expiration time to now (expired). */ 429 rt->rt_expire = time.tv_sec; 430 } 431 #endif 432 if (rt->rt_expire) { 433 rt->rt_flags &= ~RTF_REJECT; 434 if (la->la_asked == 0 || rt->rt_expire != time.tv_sec) { 435 rt->rt_expire = time.tv_sec; 436 if (la->la_asked++ < arp_maxtries) 437 arprequest(ifp, 438 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 439 &SIN(dst)->sin_addr, 440 LLADDR(ifp->if_sadl)); 441 else { 442 rt->rt_flags |= RTF_REJECT; 443 rt->rt_expire += arpt_down; 444 la->la_asked = 0; 445 } 446 } 447 } 448 return (0); 449 } 450 451 /* 452 * Common length and type checks are done here, 453 * then the protocol-specific routine is called. 454 */ 455 void 456 arpintr() 457 { 458 register struct mbuf *m; 459 register struct arphdr *ar; 460 int s; 461 462 while (arpintrq.ifq_head) { 463 s = splimp(); 464 IF_DEQUEUE(&arpintrq, m); 465 splx(s); 466 if (m == 0 || (m->m_flags & M_PKTHDR) == 0) 467 panic("arpintr"); 468 469 if (m->m_len >= sizeof(struct arphdr) && 470 (ar = mtod(m, struct arphdr *)) && 471 /* XXX ntohs(ar->ar_hrd) == ARPHRD_ETHER && */ 472 m->m_len >= 473 sizeof(struct arphdr) + 2 * (ar->ar_hln + ar->ar_pln)) 474 switch (ntohs(ar->ar_pro)) { 475 476 case ETHERTYPE_IP: 477 case ETHERTYPE_IPTRAILERS: 478 in_arpinput(m); 479 continue; 480 } 481 m_freem(m); 482 } 483 } 484 485 /* 486 * ARP for Internet protocols on 10 Mb/s Ethernet. 487 * Algorithm is that given in RFC 826. 488 * In addition, a sanity check is performed on the sender 489 * protocol address, to catch impersonators. 490 * We no longer handle negotiations for use of trailer protocol: 491 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 492 * along with IP replies if we wanted trailers sent to us, 493 * and also sent them in response to IP replies. 494 * This allowed either end to announce the desire to receive 495 * trailer packets. 496 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 497 * but formerly didn't normally send requests. 498 */ 499 static void 500 in_arpinput(m) 501 struct mbuf *m; 502 { 503 struct arphdr *ah; 504 register struct ifnet *ifp = m->m_pkthdr.rcvif; 505 register struct llinfo_arp *la = 0; 506 register struct rtentry *rt; 507 struct in_ifaddr *ia; 508 struct sockaddr_dl *sdl; 509 struct sockaddr sa; 510 struct in_addr isaddr, itaddr, myaddr; 511 int op; 512 513 ah = mtod(m, struct arphdr *); 514 op = ntohs(ah->ar_op); 515 bcopy((caddr_t)ar_spa(ah), (caddr_t)&isaddr, sizeof (isaddr)); 516 bcopy((caddr_t)ar_tpa(ah), (caddr_t)&itaddr, sizeof (itaddr)); 517 518 /* 519 * If the target IP address is zero, ignore the packet. 520 * This prevents the code below from tring to answer 521 * when we are using IP address zero (booting). 522 */ 523 if (in_nullhost(itaddr)) 524 goto out; 525 526 /* 527 * If the source IP address is zero, this is most likely a 528 * confused host trying to use IP address zero. (Windoze?) 529 * XXX: Should we bother trying to reply to these? 530 */ 531 if (in_nullhost(isaddr)) 532 goto out; 533 534 /* 535 * Search for a matching interface address 536 * or any address on the interface to use 537 * as a dummy address in the rest of this function 538 */ 539 INADDR_TO_IA(itaddr, ia); 540 if (ia == NULL) { 541 INADDR_TO_IA(isaddr, ia); 542 if (ia == NULL) { 543 IFP_TO_IA(ifp, ia); 544 if (ia == NULL) goto out; 545 } 546 } 547 myaddr = ia->ia_addr.sin_addr; 548 549 if (!bcmp((caddr_t)ar_sha(ah), LLADDR(ifp->if_sadl), 550 ifp->if_data.ifi_addrlen)) 551 goto out; /* it's from me, ignore it. */ 552 553 if (!bcmp((caddr_t)ar_sha(ah), (caddr_t)ifp->if_broadcastaddr, 554 ifp->if_data.ifi_addrlen)) { 555 log(LOG_ERR, 556 "%s: arp: link address is broadcast for IP address %x!\n", 557 ifp->if_xname, ntohl(isaddr.s_addr)); 558 goto out; 559 } 560 561 if (in_hosteq(isaddr, myaddr)) { 562 log(LOG_ERR, 563 "duplicate IP address %08x sent from link address %s\n", 564 ntohl(isaddr.s_addr), lla_snprintf(ar_sha(ah), ah->ar_hln)); 565 itaddr = myaddr; 566 goto reply; 567 } 568 la = arplookup(&isaddr, in_hosteq(itaddr, myaddr), 0); 569 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { 570 if (sdl->sdl_alen && 571 bcmp((caddr_t)ar_sha(ah), LLADDR(sdl), sdl->sdl_alen)) 572 log(LOG_INFO, "arp info overwritten for %08x by %s\n", 573 ntohl(isaddr.s_addr), 574 lla_snprintf(ar_sha(ah), ah->ar_hln)); 575 /* 576 * sanity check for the address length. 577 * XXX this does not work for protocols with variable address 578 * length. -is 579 */ 580 if (sdl->sdl_alen && 581 sdl->sdl_alen != ah->ar_hln) { 582 log(LOG_WARNING, 583 "arp from %08x: new addr len %d, was %d", 584 ntohl(isaddr.s_addr), ah->ar_hln, sdl->sdl_alen); 585 } 586 if (ifp->if_data.ifi_addrlen != ah->ar_hln) { 587 log(LOG_WARNING, 588 "arp from %08x: addr len: new %d, i/f %d (ignored)", 589 ntohl(isaddr.s_addr), ah->ar_hln, 590 ifp->if_data.ifi_addrlen); 591 goto reply; 592 } 593 bcopy((caddr_t)ar_sha(ah), LLADDR(sdl), 594 sdl->sdl_alen = ah->ar_hln); 595 if (rt->rt_expire) 596 rt->rt_expire = time.tv_sec + arpt_keep; 597 rt->rt_flags &= ~RTF_REJECT; 598 la->la_asked = 0; 599 if (la->la_hold) { 600 (*ifp->if_output)(ifp, la->la_hold, 601 rt_key(rt), rt); 602 la->la_hold = 0; 603 } 604 } 605 reply: 606 if (op != ARPOP_REQUEST) { 607 out: 608 m_freem(m); 609 return; 610 } 611 if (in_hosteq(itaddr, myaddr)) { 612 /* I am the target */ 613 bcopy((caddr_t)ar_sha(ah), (caddr_t)ar_tha(ah), ah->ar_hln); 614 bcopy(LLADDR(ifp->if_sadl), (caddr_t)ar_sha(ah), ah->ar_hln); 615 } else { 616 la = arplookup(&itaddr, 0, SIN_PROXY); 617 if (la == 0) 618 goto out; 619 rt = la->la_rt; 620 bcopy((caddr_t)ar_sha(ah), (caddr_t)ar_tha(ah), ah->ar_hln); 621 sdl = SDL(rt->rt_gateway); 622 bcopy(LLADDR(sdl), (caddr_t)ar_sha(ah), ah->ar_hln); 623 } 624 625 bcopy((caddr_t)ar_spa(ah), (caddr_t)ar_tpa(ah), ah->ar_pln); 626 bcopy((caddr_t)&itaddr, (caddr_t)ar_spa(ah), ah->ar_pln); 627 ah->ar_op = htons(ARPOP_REPLY); 628 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 629 m->m_flags &= ~(M_BCAST|M_MCAST); /* never reply by broadcast */ 630 sa.sa_family = AF_ARP; 631 sa.sa_len = 2; 632 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 633 return; 634 } 635 636 /* 637 * Free an arp entry. 638 */ 639 static void 640 arptfree(la) 641 register struct llinfo_arp *la; 642 { 643 register struct rtentry *rt = la->la_rt; 644 register struct sockaddr_dl *sdl; 645 646 if (rt == 0) 647 panic("arptfree"); 648 if (rt->rt_refcnt > 0 && (sdl = SDL(rt->rt_gateway)) && 649 sdl->sdl_family == AF_LINK) { 650 sdl->sdl_alen = 0; 651 la->la_asked = 0; 652 rt->rt_flags &= ~RTF_REJECT; 653 return; 654 } 655 rtrequest(RTM_DELETE, rt_key(rt), (struct sockaddr *)0, rt_mask(rt), 656 0, (struct rtentry **)0); 657 } 658 659 /* 660 * Lookup or enter a new address in arptab. 661 */ 662 static struct llinfo_arp * 663 arplookup(addr, create, proxy) 664 struct in_addr *addr; 665 int create, proxy; 666 { 667 register struct rtentry *rt; 668 static struct sockaddr_inarp sin; 669 670 sin.sin_len = sizeof(sin); 671 sin.sin_family = AF_INET; 672 sin.sin_addr = *addr; 673 sin.sin_other = proxy ? SIN_PROXY : 0; 674 rt = rtalloc1(sintosa(&sin), create); 675 if (rt == 0) 676 return (0); 677 rt->rt_refcnt--; 678 if ((rt->rt_flags & RTF_GATEWAY) || (rt->rt_flags & RTF_LLINFO) == 0 || 679 rt->rt_gateway->sa_family != AF_LINK) { 680 if (create) 681 log(LOG_DEBUG, "arplookup: unable to enter address for %x\n", 682 ntohl(addr->s_addr)); 683 return (0); 684 } 685 return ((struct llinfo_arp *)rt->rt_llinfo); 686 } 687 688 int 689 arpioctl(cmd, data) 690 u_long cmd; 691 caddr_t data; 692 { 693 694 return (EOPNOTSUPP); 695 } 696 697 void 698 arp_ifinit(ifp, ifa) 699 struct ifnet *ifp; 700 struct ifaddr *ifa; 701 { 702 struct in_addr *ip; 703 704 /* 705 * Warn the user if another station has this IP address, 706 * but only if the interface IP address is not zero. 707 */ 708 ip = &IA_SIN(ifa)->sin_addr; 709 if (!in_nullhost(*ip)) 710 arprequest(ifp, ip, ip, LLADDR(ifp->if_sadl)); 711 712 ifa->ifa_rtrequest = arp_rtrequest; 713 ifa->ifa_flags |= RTF_CLONING; 714 } 715 716 /* 717 * Called from 10 Mb/s Ethernet interrupt handlers 718 * when ether packet type ETHERTYPE_REVARP 719 * is received. Common length and type checks are done here, 720 * then the protocol-specific routine is called. 721 */ 722 void 723 revarpinput(m) 724 struct mbuf *m; 725 { 726 struct arphdr *ar; 727 728 if (m->m_len < sizeof(struct arphdr)) 729 goto out; 730 ar = mtod(m, struct arphdr *); 731 #if 0 /* XXX I don't think we need this... and it will prevent other LL */ 732 if (ntohs(ar->ar_hrd) != ARPHRD_ETHER) 733 goto out; 734 #endif 735 if (m->m_len < sizeof(struct arphdr) + 2 * (ar->ar_hln + ar->ar_pln)) 736 goto out; 737 switch (ntohs(ar->ar_pro)) { 738 739 case ETHERTYPE_IP: 740 case ETHERTYPE_IPTRAILERS: 741 in_revarpinput(m); 742 return; 743 744 default: 745 break; 746 } 747 out: 748 m_freem(m); 749 } 750 751 /* 752 * RARP for Internet protocols on 10 Mb/s Ethernet. 753 * Algorithm is that given in RFC 903. 754 * We are only using for bootstrap purposes to get an ip address for one of 755 * our interfaces. Thus we support no user-interface. 756 * 757 * Since the contents of the RARP reply are specific to the interface that 758 * sent the request, this code must ensure that they are properly associated. 759 * 760 * Note: also supports ARP via RARP packets, per the RFC. 761 */ 762 void 763 in_revarpinput(m) 764 struct mbuf *m; 765 { 766 struct ifnet *ifp; 767 struct arphdr *ah; 768 int op; 769 770 ah = mtod(m, struct arphdr *); 771 op = ntohs(ah->ar_op); 772 switch (op) { 773 case ARPOP_REQUEST: 774 case ARPOP_REPLY: /* per RFC */ 775 in_arpinput(m); 776 return; 777 case ARPOP_REVREPLY: 778 break; 779 case ARPOP_REVREQUEST: /* handled by rarpd(8) */ 780 default: 781 goto out; 782 } 783 if (!revarp_in_progress) 784 goto out; 785 ifp = m->m_pkthdr.rcvif; 786 if (ifp != myip_ifp) /* !same interface */ 787 goto out; 788 if (myip_initialized) 789 goto wake; 790 if (bcmp(ar_tha(ah), LLADDR(ifp->if_sadl), ifp->if_sadl->sdl_alen)) 791 goto out; 792 bcopy((caddr_t)ar_spa(ah), (caddr_t)&srv_ip, sizeof(srv_ip)); 793 bcopy((caddr_t)ar_tpa(ah), (caddr_t)&myip, sizeof(myip)); 794 myip_initialized = 1; 795 wake: /* Do wakeup every time in case it was missed. */ 796 wakeup((caddr_t)&myip); 797 798 out: 799 m_freem(m); 800 } 801 802 /* 803 * Send a RARP request for the ip address of the specified interface. 804 * The request should be RFC 903-compliant. 805 */ 806 void 807 revarprequest(ifp) 808 struct ifnet *ifp; 809 { 810 struct sockaddr sa; 811 struct mbuf *m; 812 struct arphdr *ah; 813 814 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 815 return; 816 m->m_len = sizeof(*ah) + 2*sizeof(struct in_addr) + 817 2*ifp->if_data.ifi_addrlen; 818 m->m_pkthdr.len = m->m_len; 819 MH_ALIGN(m, m->m_len); 820 ah = mtod(m, struct arphdr *); 821 bzero((caddr_t)ah, m->m_len); 822 ah->ar_pro = htons(ETHERTYPE_IP); 823 ah->ar_hln = ifp->if_data.ifi_addrlen; /* hardware address length */ 824 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 825 ah->ar_op = htons(ARPOP_REVREQUEST); 826 827 bcopy(LLADDR(ifp->if_sadl), (caddr_t)ar_sha(ah), ah->ar_hln); 828 bcopy(LLADDR(ifp->if_sadl), (caddr_t)ar_tha(ah), ah->ar_hln); 829 830 sa.sa_family = AF_ARP; 831 sa.sa_len = 2; 832 m->m_flags |= M_BCAST; 833 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 834 835 } 836 837 /* 838 * RARP for the ip address of the specified interface, but also 839 * save the ip address of the server that sent the answer. 840 * Timeout if no response is received. 841 */ 842 int 843 revarpwhoarewe(ifp, serv_in, clnt_in) 844 struct ifnet *ifp; 845 struct in_addr *serv_in; 846 struct in_addr *clnt_in; 847 { 848 int result, count = 20; 849 850 if (!myip_initialized) { 851 myip_ifp = ifp; 852 revarp_in_progress = 1; 853 while (count--) { 854 revarprequest(ifp); 855 result = tsleep((caddr_t)&myip, PSOCK, "revarp", hz/2); 856 if (result != EWOULDBLOCK) 857 break; 858 } 859 revarp_in_progress = 0; 860 } 861 if (!myip_initialized) 862 return ENETUNREACH; 863 864 bcopy((caddr_t)&srv_ip, serv_in, sizeof(*serv_in)); 865 bcopy((caddr_t)&myip, clnt_in, sizeof(*clnt_in)); 866 return 0; 867 } 868 869 /* For compatibility: only saves interface address. */ 870 int 871 revarpwhoami(in, ifp) 872 struct in_addr *in; 873 struct ifnet *ifp; 874 { 875 struct in_addr server; 876 return (revarpwhoarewe(ifp, &server, in)); 877 } 878 879 880 #ifdef DDB 881 882 #include <machine/db_machdep.h> 883 #include <ddb/db_interface.h> 884 #include <ddb/db_output.h> 885 static void 886 db_print_sa(sa) 887 struct sockaddr *sa; 888 { 889 int len; 890 u_char *p; 891 892 if (sa == 0) { 893 db_printf("[NULL]"); 894 return; 895 } 896 897 p = (u_char*)sa; 898 len = sa->sa_len; 899 db_printf("["); 900 while (len > 0) { 901 db_printf("%d", *p); 902 p++; len--; 903 if (len) db_printf(","); 904 } 905 db_printf("]\n"); 906 } 907 static void 908 db_print_ifa(ifa) 909 struct ifaddr *ifa; 910 { 911 if (ifa == 0) 912 return; 913 db_printf(" ifa_addr="); 914 db_print_sa(ifa->ifa_addr); 915 db_printf(" ifa_dsta="); 916 db_print_sa(ifa->ifa_dstaddr); 917 db_printf(" ifa_mask="); 918 db_print_sa(ifa->ifa_netmask); 919 db_printf(" flags=0x%x,refcnt=%d,metric=%d\n", 920 ifa->ifa_flags, 921 ifa->ifa_refcnt, 922 ifa->ifa_metric); 923 } 924 static void 925 db_print_llinfo(li) 926 caddr_t li; 927 { 928 struct llinfo_arp *la; 929 930 if (li == 0) 931 return; 932 la = (struct llinfo_arp *)li; 933 db_printf(" la_rt=%p la_hold=%p, la_asked=0x%lx\n", 934 la->la_rt, la->la_hold, la->la_asked); 935 } 936 /* 937 * Function to pass to rn_walktree(). 938 * Return non-zero error to abort walk. 939 */ 940 static int 941 db_show_radix_node(rn, w) 942 struct radix_node *rn; 943 void *w; 944 { 945 struct rtentry *rt = (struct rtentry *)rn; 946 947 db_printf("rtentry=%p", rt); 948 949 db_printf(" flags=0x%x refcnt=%d use=%ld expire=%ld\n", 950 rt->rt_flags, rt->rt_refcnt, 951 rt->rt_use, rt->rt_expire); 952 953 db_printf(" key="); db_print_sa(rt_key(rt)); 954 db_printf(" mask="); db_print_sa(rt_mask(rt)); 955 db_printf(" gw="); db_print_sa(rt->rt_gateway); 956 957 db_printf(" ifp=%p ", rt->rt_ifp); 958 if (rt->rt_ifp) 959 db_printf("(%s)", rt->rt_ifp->if_xname); 960 else 961 db_printf("(NULL)"); 962 963 db_printf(" ifa=%p\n", rt->rt_ifa); 964 db_print_ifa(rt->rt_ifa); 965 966 db_printf(" genmask="); db_print_sa(rt->rt_genmask); 967 968 db_printf(" gwroute=%p llinfo=%p\n", 969 rt->rt_gwroute, rt->rt_llinfo); 970 db_print_llinfo(rt->rt_llinfo); 971 972 return (0); 973 } 974 /* 975 * Function to print all the route trees. 976 * Use this from ddb: "call db_show_arptab" 977 */ 978 int 979 db_show_arptab() 980 { 981 struct radix_node_head *rnh; 982 rnh = rt_tables[AF_INET]; 983 db_printf("Route tree for AF_INET\n"); 984 if (rnh == NULL) { 985 db_printf(" (not initialized)\n"); 986 return (0); 987 } 988 rn_walktree(rnh, db_show_radix_node, NULL); 989 return (0); 990 } 991 #endif 992 #endif /* INET */ 993