1 /* 2 * Copyright (c) 1983, 1988, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgment: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * $FreeBSD: src/sbin/routed/input.c,v 1.7.2.1 2001/08/01 09:01:45 obrien Exp $ 34 */ 35 36 #include "defs.h" 37 38 #if !defined(sgi) && !defined(__NetBSD__) 39 static char sccsid[] __attribute__((unused)) = "@(#)input.c 8.1 (Berkeley) 6/5/93"; 40 #elif defined(__NetBSD__) 41 #include <sys/cdefs.h> 42 __RCSID("$NetBSD$"); 43 #endif 44 45 static void input(struct sockaddr_in *, struct interface *, struct interface *, 46 struct rip *, int); 47 static void input_route(naddr, naddr, struct rt_spare *, struct netinfo *); 48 static int ck_passwd(struct interface *, struct rip *, void *, 49 naddr, struct msg_limit *); 50 51 52 /* process RIP input 53 */ 54 void 55 read_rip(int sock, 56 struct interface *sifp) 57 { 58 struct sockaddr_in from; 59 struct interface *aifp; 60 int cc; 61 socklen_t fromlen; 62 #ifdef USE_PASSIFNAME 63 static struct msg_limit bad_name; 64 struct { 65 char ifname[IFNAMSIZ]; 66 union pkt_buf pbuf; 67 } inbuf; 68 #else 69 struct { 70 union pkt_buf pbuf; 71 } inbuf; 72 #endif 73 74 75 for (;;) { 76 fromlen = sizeof(from); 77 cc = recvfrom(sock, &inbuf, sizeof(inbuf), 0, 78 (struct sockaddr*)&from, &fromlen); 79 if (cc <= 0) { 80 if (cc < 0 && errno != EWOULDBLOCK) 81 LOGERR("recvfrom(rip)"); 82 break; 83 } 84 if (fromlen != sizeof(struct sockaddr_in)) 85 logbad(1,"impossible recvfrom(rip) fromlen=%d", 86 fromlen); 87 88 /* aifp is the "authenticated" interface via which the packet 89 * arrived. In fact, it is only the interface on which 90 * the packet should have arrived based on is source 91 * address. 92 * sifp is interface associated with the socket through which 93 * the packet was received. 94 */ 95 #ifdef USE_PASSIFNAME 96 if ((cc -= sizeof(inbuf.ifname)) < 0) 97 logbad(0,"missing USE_PASSIFNAME; only %d bytes", 98 cc+sizeof(inbuf.ifname)); 99 100 /* check the remote interfaces first */ 101 for (aifp = remote_if; aifp; aifp = aifp->int_rlink) { 102 if (aifp->int_addr == from.sin_addr.s_addr) 103 break; 104 } 105 if (aifp == NULL) { 106 aifp = ifwithname(inbuf.ifname, 0); 107 if (aifp == NULL) { 108 msglim(&bad_name, from.sin_addr.s_addr, 109 "impossible interface name %.*s", 110 IFNAMSIZ, inbuf.ifname); 111 } else if (((aifp->int_if_flags & IFF_POINTOPOINT) 112 && aifp->int_dstaddr!=from.sin_addr.s_addr) 113 || (!(aifp->int_if_flags & IFF_POINTOPOINT) 114 && !on_net(from.sin_addr.s_addr, 115 aifp->int_net, 116 aifp->int_mask))) { 117 /* If it came via the wrong interface, do not 118 * trust it. 119 */ 120 aifp = NULL; 121 } 122 } 123 #else 124 aifp = iflookup(from.sin_addr.s_addr); 125 #endif 126 if (sifp == NULL) 127 sifp = aifp; 128 129 input(&from, sifp, aifp, &inbuf.pbuf.rip, cc); 130 } 131 } 132 133 134 /* Process a RIP packet 135 */ 136 static void 137 input(struct sockaddr_in *from, /* received from this IP address */ 138 struct interface *sifp, /* interface of incoming socket */ 139 struct interface *aifp, /* "authenticated" interface */ 140 struct rip *rip, 141 int cc) 142 { 143 # define FROM_NADDR from->sin_addr.s_addr 144 static struct msg_limit use_auth, bad_len, bad_mask; 145 static struct msg_limit unk_router, bad_router, bad_nhop; 146 147 struct rt_entry *rt; 148 struct rt_spare new; 149 struct netinfo *n, *lim; 150 struct interface *ifp1; 151 naddr gate, mask, v1_mask, dst, ddst_h = 0; 152 struct auth *ap; 153 struct tgate *tg = NULL; 154 struct tgate_net *tn; 155 int i, j; 156 157 /* Notice when we hear from a remote gateway 158 */ 159 if (aifp != NULL 160 && (aifp->int_state & IS_REMOTE)) 161 aifp->int_act_time = now.tv_sec; 162 163 trace_rip("Recv", "from", from, sifp, rip, cc); 164 165 if (rip->rip_vers == 0) { 166 msglim(&bad_router, FROM_NADDR, 167 "RIP version 0, cmd %d, packet received from %s", 168 rip->rip_cmd, naddr_ntoa(FROM_NADDR)); 169 return; 170 } else if (rip->rip_vers > RIPv2) { 171 rip->rip_vers = RIPv2; 172 } 173 if (cc > (int)OVER_MAXPACKETSIZE) { 174 msglim(&bad_router, FROM_NADDR, 175 "packet at least %d bytes too long received from %s", 176 cc-MAXPACKETSIZE, naddr_ntoa(FROM_NADDR)); 177 return; 178 } 179 180 n = rip->rip_nets; 181 lim = (struct netinfo *)((char*)rip + cc); 182 183 /* Notice authentication. 184 * As required by section 4.2 in RFC 1723, discard authenticated 185 * RIPv2 messages, but only if configured for that silliness. 186 * 187 * RIPv2 authentication is lame. Why authenticate queries? 188 * Why should a RIPv2 implementation with authentication disabled 189 * not be able to listen to RIPv2 packets with authentication, while 190 * RIPv1 systems will listen? Crazy! 191 */ 192 if (!auth_ok 193 && rip->rip_vers == RIPv2 194 && n < lim && n->n_family == RIP_AF_AUTH) { 195 msglim(&use_auth, FROM_NADDR, 196 "RIPv2 message with authentication from %s discarded", 197 naddr_ntoa(FROM_NADDR)); 198 return; 199 } 200 201 switch (rip->rip_cmd) { 202 case RIPCMD_REQUEST: 203 /* For mere requests, be a little sloppy about the source 204 */ 205 if (aifp == NULL) 206 aifp = sifp; 207 208 /* Are we talking to ourself or a remote gateway? 209 */ 210 ifp1 = ifwithaddr(FROM_NADDR, 0, 1); 211 if (ifp1) { 212 if (ifp1->int_state & IS_REMOTE) { 213 /* remote gateway */ 214 aifp = ifp1; 215 if (check_remote(aifp)) { 216 aifp->int_act_time = now.tv_sec; 217 if_ok(aifp, "remote "); 218 } 219 } else if (from->sin_port == htons(RIP_PORT)) { 220 trace_pkt(" discard our own RIP request"); 221 return; 222 } 223 } 224 225 /* did the request come from a router? 226 */ 227 if (from->sin_port == htons(RIP_PORT)) { 228 /* yes, ignore the request if RIP is off so that 229 * the router does not depend on us. 230 */ 231 if (rip_sock < 0 232 || (aifp != NULL 233 && IS_RIP_OUT_OFF(aifp->int_state))) { 234 trace_pkt(" discard request while RIP off"); 235 return; 236 } 237 } 238 239 /* According to RFC 1723, we should ignore unauthenticated 240 * queries. That is too silly to bother with. Sheesh! 241 * Are forwarding tables supposed to be secret, when 242 * a bad guy can infer them with test traffic? When RIP 243 * is still the most common router-discovery protocol 244 * and so hosts need to send queries that will be answered? 245 * What about `rtquery`? 246 * Maybe on firewalls you'd care, but not enough to 247 * give up the diagnostic facilities of remote probing. 248 */ 249 250 if (n >= lim) { 251 msglim(&bad_len, FROM_NADDR, "empty request from %s", 252 naddr_ntoa(FROM_NADDR)); 253 return; 254 } 255 if (cc%sizeof(*n) != sizeof(struct rip)%sizeof(*n)) { 256 msglim(&bad_len, FROM_NADDR, 257 "request of bad length (%d) from %s", 258 cc, naddr_ntoa(FROM_NADDR)); 259 } 260 261 if (rip->rip_vers == RIPv2 262 && (aifp == NULL || (aifp->int_state & IS_NO_RIPV1_OUT))) { 263 v12buf.buf->rip_vers = RIPv2; 264 /* If we have a secret but it is a cleartext secret, 265 * do not disclose our secret unless the other guy 266 * already knows it. 267 */ 268 ap = find_auth(aifp); 269 if (ap != NULL && ap->type == RIP_AUTH_PW 270 && n->n_family == RIP_AF_AUTH 271 && !ck_passwd(aifp,rip,lim,FROM_NADDR,&use_auth)) 272 ap = NULL; 273 } else { 274 v12buf.buf->rip_vers = RIPv1; 275 ap = NULL; 276 } 277 clr_ws_buf(&v12buf, ap); 278 279 do { 280 n->n_metric = ntohl(n->n_metric); 281 282 /* A single entry with family RIP_AF_UNSPEC and 283 * metric HOPCNT_INFINITY means "all routes". 284 * We respond to routers only if we are acting 285 * as a supplier, or to anyone other than a router 286 * (i.e. a query). 287 */ 288 if (n->n_family == RIP_AF_UNSPEC 289 && n->n_metric == HOPCNT_INFINITY) { 290 /* Answer a query from a utility program 291 * with all we know. 292 */ 293 if (from->sin_port != htons(RIP_PORT)) { 294 supply(from, aifp, OUT_QUERY, 0, 295 rip->rip_vers, ap != NULL); 296 return; 297 } 298 299 /* A router trying to prime its tables. 300 * Filter the answer in the about same way 301 * broadcasts are filtered. 302 * 303 * Only answer a router if we are a supplier 304 * to keep an unwary host that is just starting 305 * from picking us as a router. 306 */ 307 if (aifp == NULL) { 308 trace_pkt("ignore distant router"); 309 return; 310 } 311 if (!supplier 312 || IS_RIP_OFF(aifp->int_state)) { 313 trace_pkt("ignore; not supplying"); 314 return; 315 } 316 317 /* Do not answer a RIPv1 router if 318 * we are sending RIPv2. But do offer 319 * poor man's router discovery. 320 */ 321 if ((aifp->int_state & IS_NO_RIPV1_OUT) 322 && rip->rip_vers == RIPv1) { 323 if (!(aifp->int_state & IS_PM_RDISC)) { 324 trace_pkt("ignore; sending RIPv2"); 325 return; 326 } 327 328 v12buf.n->n_family = RIP_AF_INET; 329 v12buf.n->n_dst = RIP_DEFAULT; 330 i = aifp->int_d_metric; 331 if (NULL != (rt = rtget(RIP_DEFAULT, 0))) 332 i = MIN(i, (rt->rt_metric 333 +aifp->int_metric+1)); 334 v12buf.n->n_metric = htonl(i); 335 v12buf.n++; 336 break; 337 } 338 339 /* Respond with RIPv1 instead of RIPv2 if 340 * that is what we are broadcasting on the 341 * interface to keep the remote router from 342 * getting the wrong initial idea of the 343 * routes we send. 344 */ 345 supply(from, aifp, OUT_UNICAST, 0, 346 (aifp->int_state & IS_NO_RIPV1_OUT) 347 ? RIPv2 : RIPv1, 348 ap != NULL); 349 return; 350 } 351 352 /* Ignore authentication */ 353 if (n->n_family == RIP_AF_AUTH) 354 continue; 355 356 if (n->n_family != RIP_AF_INET) { 357 msglim(&bad_router, FROM_NADDR, 358 "request from %s for unsupported" 359 " (af %d) %s", 360 naddr_ntoa(FROM_NADDR), 361 ntohs(n->n_family), 362 naddr_ntoa(n->n_dst)); 363 return; 364 } 365 366 /* We are being asked about a specific destination. 367 */ 368 dst = n->n_dst; 369 if (!check_dst(dst)) { 370 msglim(&bad_router, FROM_NADDR, 371 "bad queried destination %s from %s", 372 naddr_ntoa(dst), 373 naddr_ntoa(FROM_NADDR)); 374 return; 375 } 376 377 /* decide what mask was intended */ 378 if (rip->rip_vers == RIPv1 379 || 0 == (mask = ntohl(n->n_mask)) 380 || 0 != (ntohl(dst) & ~mask)) 381 mask = ripv1_mask_host(dst, aifp); 382 383 /* try to find the answer */ 384 rt = rtget(dst, mask); 385 if (!rt && dst != RIP_DEFAULT) 386 rt = rtfind(n->n_dst); 387 388 if (v12buf.buf->rip_vers != RIPv1) 389 v12buf.n->n_mask = mask; 390 if (rt == NULL) { 391 /* we do not have the answer */ 392 v12buf.n->n_metric = HOPCNT_INFINITY; 393 } else { 394 /* we have the answer, so compute the 395 * right metric and next hop. 396 */ 397 v12buf.n->n_family = RIP_AF_INET; 398 v12buf.n->n_dst = dst; 399 v12buf.n->n_metric = (rt->rt_metric+1 400 + ((aifp!=NULL) 401 ? aifp->int_metric 402 : 1)); 403 if (v12buf.n->n_metric > HOPCNT_INFINITY) 404 v12buf.n->n_metric = HOPCNT_INFINITY; 405 if (v12buf.buf->rip_vers != RIPv1) { 406 v12buf.n->n_tag = rt->rt_tag; 407 v12buf.n->n_mask = mask; 408 if (aifp != NULL 409 && on_net(rt->rt_gate, 410 aifp->int_net, 411 aifp->int_mask) 412 && rt->rt_gate != aifp->int_addr) 413 v12buf.n->n_nhop = rt->rt_gate; 414 } 415 } 416 v12buf.n->n_metric = htonl(v12buf.n->n_metric); 417 418 /* Stop paying attention if we fill the output buffer. 419 */ 420 if (++v12buf.n >= v12buf.lim) 421 break; 422 } while (++n < lim); 423 424 /* Send the answer about specific routes. 425 */ 426 if (ap != NULL && ap->type == RIP_AUTH_MD5) 427 end_md5_auth(&v12buf, ap); 428 429 if (from->sin_port != htons(RIP_PORT)) { 430 /* query */ 431 output(OUT_QUERY, from, aifp, 432 v12buf.buf, 433 ((char *)v12buf.n - (char*)v12buf.buf)); 434 } else if (supplier) { 435 output(OUT_UNICAST, from, aifp, 436 v12buf.buf, 437 ((char *)v12buf.n - (char*)v12buf.buf)); 438 } else { 439 /* Only answer a router if we are a supplier 440 * to keep an unwary host that is just starting 441 * from picking us an a router. 442 */ 443 ; 444 } 445 return; 446 447 case RIPCMD_TRACEON: 448 case RIPCMD_TRACEOFF: 449 /* Notice that trace messages are turned off for all possible 450 * abuse if _PATH_TRACE is undefined in pathnames.h. 451 * Notice also that because of the way the trace file is 452 * handled in trace.c, no abuse is plausible even if 453 * _PATH_TRACE_ is defined. 454 * 455 * First verify message came from a privileged port. */ 456 if (ntohs(from->sin_port) > IPPORT_RESERVED) { 457 msglog("trace command from untrusted port on %s", 458 naddr_ntoa(FROM_NADDR)); 459 return; 460 } 461 if (aifp == NULL) { 462 msglog("trace command from unknown router %s", 463 naddr_ntoa(FROM_NADDR)); 464 return; 465 } 466 if (rip->rip_cmd == RIPCMD_TRACEON) { 467 rip->rip_tracefile[cc-4] = '\0'; 468 set_tracefile((char*)rip->rip_tracefile, 469 "trace command: %s\n", 0); 470 } else { 471 trace_off("tracing turned off by %s", 472 naddr_ntoa(FROM_NADDR)); 473 } 474 return; 475 476 case RIPCMD_RESPONSE: 477 if (cc%sizeof(*n) != sizeof(struct rip)%sizeof(*n)) { 478 msglim(&bad_len, FROM_NADDR, 479 "response of bad length (%d) from %s", 480 cc, naddr_ntoa(FROM_NADDR)); 481 } 482 483 /* verify message came from a router */ 484 if (from->sin_port != ntohs(RIP_PORT)) { 485 msglim(&bad_router, FROM_NADDR, 486 " discard RIP response from unknown port" 487 " %d on host %s", ntohs(from->sin_port), 488 naddr_ntoa(FROM_NADDR)); 489 return; 490 } 491 492 if (rip_sock < 0) { 493 trace_pkt(" discard response while RIP off"); 494 return; 495 } 496 497 /* Are we talking to ourself or a remote gateway? 498 */ 499 ifp1 = ifwithaddr(FROM_NADDR, 0, 1); 500 if (ifp1) { 501 if (ifp1->int_state & IS_REMOTE) { 502 /* remote gateway */ 503 aifp = ifp1; 504 if (check_remote(aifp)) { 505 aifp->int_act_time = now.tv_sec; 506 if_ok(aifp, "remote "); 507 } 508 } else { 509 trace_pkt(" discard our own RIP response"); 510 return; 511 } 512 } 513 514 /* Accept routing packets from routers directly connected 515 * via broadcast or point-to-point networks, and from 516 * those listed in /etc/gateways. 517 */ 518 if (aifp == NULL) { 519 msglim(&unk_router, FROM_NADDR, 520 " discard response from %s" 521 " via unexpected interface", 522 naddr_ntoa(FROM_NADDR)); 523 return; 524 } 525 if (IS_RIP_IN_OFF(aifp->int_state)) { 526 trace_pkt(" discard RIPv%d response" 527 " via disabled interface %s", 528 rip->rip_vers, aifp->int_name); 529 return; 530 } 531 532 if (n >= lim) { 533 msglim(&bad_len, FROM_NADDR, "empty response from %s", 534 naddr_ntoa(FROM_NADDR)); 535 return; 536 } 537 538 if (((aifp->int_state & IS_NO_RIPV1_IN) 539 && rip->rip_vers == RIPv1) 540 || ((aifp->int_state & IS_NO_RIPV2_IN) 541 && rip->rip_vers != RIPv1)) { 542 trace_pkt(" discard RIPv%d response", 543 rip->rip_vers); 544 return; 545 } 546 547 /* Ignore routes via dead interface. 548 */ 549 if (aifp->int_state & IS_BROKE) { 550 trace_pkt("discard response via broken interface %s", 551 aifp->int_name); 552 return; 553 } 554 555 /* If the interface cares, ignore bad routers. 556 * Trace but do not log this problem, because where it 557 * happens, it happens frequently. 558 */ 559 if (aifp->int_state & IS_DISTRUST) { 560 tg = tgates; 561 while (tg->tgate_addr != FROM_NADDR) { 562 tg = tg->tgate_next; 563 if (tg == NULL) { 564 trace_pkt(" discard RIP response" 565 " from untrusted router %s", 566 naddr_ntoa(FROM_NADDR)); 567 return; 568 } 569 } 570 } 571 572 /* Authenticate the packet if we have a secret. 573 * If we do not have any secrets, ignore the error in 574 * RFC 1723 and accept it regardless. 575 */ 576 if (aifp->int_auth[0].type != RIP_AUTH_NONE 577 && rip->rip_vers != RIPv1 578 && !ck_passwd(aifp,rip,lim,FROM_NADDR,&use_auth)) 579 return; 580 581 do { 582 if (n->n_family == RIP_AF_AUTH) 583 continue; 584 585 n->n_metric = ntohl(n->n_metric); 586 dst = n->n_dst; 587 if (n->n_family != RIP_AF_INET 588 && (n->n_family != RIP_AF_UNSPEC 589 || dst != RIP_DEFAULT)) { 590 msglim(&bad_router, FROM_NADDR, 591 "route from %s to unsupported" 592 " address family=%d destination=%s", 593 naddr_ntoa(FROM_NADDR), 594 n->n_family, 595 naddr_ntoa(dst)); 596 continue; 597 } 598 if (!check_dst(dst)) { 599 msglim(&bad_router, FROM_NADDR, 600 "bad destination %s from %s", 601 naddr_ntoa(dst), 602 naddr_ntoa(FROM_NADDR)); 603 return; 604 } 605 if (n->n_metric == 0 606 || n->n_metric > HOPCNT_INFINITY) { 607 msglim(&bad_router, FROM_NADDR, 608 "bad metric %d from %s" 609 " for destination %s", 610 n->n_metric, 611 naddr_ntoa(FROM_NADDR), 612 naddr_ntoa(dst)); 613 return; 614 } 615 616 /* Notice the next-hop. 617 */ 618 gate = FROM_NADDR; 619 if (n->n_nhop != 0) { 620 if (rip->rip_vers == RIPv1) { 621 n->n_nhop = 0; 622 } else { 623 /* Use it only if it is valid. */ 624 if (on_net(n->n_nhop, 625 aifp->int_net, aifp->int_mask) 626 && check_dst(n->n_nhop)) { 627 gate = n->n_nhop; 628 } else { 629 msglim(&bad_nhop, FROM_NADDR, 630 "router %s to %s" 631 " has bad next hop %s", 632 naddr_ntoa(FROM_NADDR), 633 naddr_ntoa(dst), 634 naddr_ntoa(n->n_nhop)); 635 n->n_nhop = 0; 636 } 637 } 638 } 639 640 if (rip->rip_vers == RIPv1 641 || 0 == (mask = ntohl(n->n_mask))) { 642 mask = ripv1_mask_host(dst,aifp); 643 } else if ((ntohl(dst) & ~mask) != 0) { 644 msglim(&bad_mask, FROM_NADDR, 645 "router %s sent bad netmask" 646 " %#lx with %s", 647 naddr_ntoa(FROM_NADDR), 648 (u_long)mask, 649 naddr_ntoa(dst)); 650 continue; 651 } 652 if (rip->rip_vers == RIPv1) 653 n->n_tag = 0; 654 655 /* Adjust metric according to incoming interface.. 656 */ 657 n->n_metric += aifp->int_metric; 658 if (n->n_metric > HOPCNT_INFINITY) 659 n->n_metric = HOPCNT_INFINITY; 660 661 /* Should we trust this route from this router? */ 662 if (tg && (tn = tg->tgate_nets)->mask != 0) { 663 for (i = 0; i < MAX_TGATE_NETS; i++, tn++) { 664 if (on_net(dst, tn->net, tn->mask) 665 && tn->mask <= mask) 666 break; 667 } 668 if (i >= MAX_TGATE_NETS || tn->mask == 0) { 669 trace_pkt(" ignored unauthorized %s", 670 addrname(dst,mask,0)); 671 continue; 672 } 673 } 674 675 /* Recognize and ignore a default route we faked 676 * which is being sent back to us by a machine with 677 * broken split-horizon. 678 * Be a little more paranoid than that, and reject 679 * default routes with the same metric we advertised. 680 */ 681 if (aifp->int_d_metric != 0 682 && dst == RIP_DEFAULT 683 && (int)n->n_metric >= aifp->int_d_metric) 684 continue; 685 686 /* We can receive aggregated RIPv2 routes that must 687 * be broken down before they are transmitted by 688 * RIPv1 via an interface on a subnet. 689 * We might also receive the same routes aggregated 690 * via other RIPv2 interfaces. 691 * This could cause duplicate routes to be sent on 692 * the RIPv1 interfaces. "Longest matching variable 693 * length netmasks" lets RIPv2 listeners understand, 694 * but breaking down the aggregated routes for RIPv1 695 * listeners can produce duplicate routes. 696 * 697 * Breaking down aggregated routes here bloats 698 * the daemon table, but does not hurt the kernel 699 * table, since routes are always aggregated for 700 * the kernel. 701 * 702 * Notice that this does not break down network 703 * routes corresponding to subnets. This is part 704 * of the defense against RS_NET_SYN. 705 */ 706 if (have_ripv1_out 707 && (((rt = rtget(dst,mask)) == NULL 708 || !(rt->rt_state & RS_NET_SYN))) 709 && (v1_mask = ripv1_mask_net(dst,0)) > mask) { 710 ddst_h = v1_mask & -v1_mask; 711 i = (v1_mask & ~mask)/ddst_h; 712 if (i >= 511) { 713 /* Punt if we would have to generate 714 * an unreasonable number of routes. 715 */ 716 if (TRACECONTENTS) 717 trace_misc("accept %s-->%s as 1" 718 " instead of %d routes", 719 addrname(dst,mask,0), 720 naddr_ntoa(FROM_NADDR), 721 i+1); 722 i = 0; 723 } else { 724 mask = v1_mask; 725 } 726 } else { 727 i = 0; 728 } 729 730 new.rts_gate = gate; 731 new.rts_router = FROM_NADDR; 732 new.rts_metric = n->n_metric; 733 new.rts_tag = n->n_tag; 734 new.rts_time = now.tv_sec; 735 new.rts_ifp = aifp; 736 new.rts_de_ag = i; 737 j = 0; 738 for (;;) { 739 input_route(dst, mask, &new, n); 740 if (++j > i) 741 break; 742 dst = htonl(ntohl(dst) + ddst_h); 743 } 744 } while (++n < lim); 745 break; 746 } 747 #undef FROM_NADDR 748 } 749 750 751 /* Process a single input route. 752 */ 753 static void 754 input_route(naddr dst, /* network order */ 755 naddr mask, 756 struct rt_spare *new, 757 struct netinfo *n) 758 { 759 int i; 760 struct rt_entry *rt; 761 struct rt_spare *rts, *rts0; 762 struct interface *ifp1; 763 764 765 /* See if the other guy is telling us to send our packets to him. 766 * Sometimes network routes arrive over a point-to-point link for 767 * the network containing the address(es) of the link. 768 * 769 * If our interface is broken, switch to using the other guy. 770 */ 771 ifp1 = ifwithaddr(dst, 1, 1); 772 if (ifp1 != NULL 773 && (!(ifp1->int_state & IS_BROKE) 774 || (ifp1->int_state & IS_PASSIVE))) 775 return; 776 777 /* Look for the route in our table. 778 */ 779 rt = rtget(dst, mask); 780 781 /* Consider adding the route if we do not already have it. 782 */ 783 if (rt == NULL) { 784 /* Ignore unknown routes being poisoned. 785 */ 786 if (new->rts_metric == HOPCNT_INFINITY) 787 return; 788 789 /* Ignore the route if it points to us */ 790 if (n->n_nhop != 0 791 && 0 != ifwithaddr(n->n_nhop, 1, 0)) 792 return; 793 794 /* If something has not gone crazy and tried to fill 795 * our memory, accept the new route. 796 */ 797 if (total_routes < MAX_ROUTES) 798 rtadd(dst, mask, 0, new); 799 return; 800 } 801 802 /* We already know about the route. Consider this update. 803 * 804 * If (rt->rt_state & RS_NET_SYN), then this route 805 * is the same as a network route we have inferred 806 * for subnets we know, in order to tell RIPv1 routers 807 * about the subnets. 808 * 809 * It is impossible to tell if the route is coming 810 * from a distant RIPv2 router with the standard 811 * netmask because that router knows about the entire 812 * network, or if it is a round-about echo of a 813 * synthetic, RIPv1 network route of our own. 814 * The worst is that both kinds of routes might be 815 * received, and the bad one might have the smaller 816 * metric. Partly solve this problem by never 817 * aggregating into such a route. Also keep it 818 * around as long as the interface exists. 819 */ 820 821 rts0 = rt->rt_spares; 822 for (rts = rts0, i = NUM_SPARES; i != 0; i--, rts++) { 823 if (rts->rts_router == new->rts_router) 824 break; 825 /* Note the worst slot to reuse, 826 * other than the current slot. 827 */ 828 if (rts0 == rt->rt_spares 829 || BETTER_LINK(rt, rts0, rts)) 830 rts0 = rts; 831 } 832 if (i != 0) { 833 /* Found a route from the router already in the table. 834 */ 835 836 /* If the new route is a route broken down from an 837 * aggregated route, and if the previous route is either 838 * not a broken down route or was broken down from a finer 839 * netmask, and if the previous route is current, 840 * then forget this one. 841 */ 842 if (new->rts_de_ag > rts->rts_de_ag 843 && now_stale <= rts->rts_time) 844 return; 845 846 /* Keep poisoned routes around only long enough to pass 847 * the poison on. Use a new timestamp for good routes. 848 */ 849 if (rts->rts_metric == HOPCNT_INFINITY 850 && new->rts_metric == HOPCNT_INFINITY) 851 new->rts_time = rts->rts_time; 852 853 /* If this is an update for the router we currently prefer, 854 * then note it. 855 */ 856 if (i == NUM_SPARES) { 857 rtchange(rt, rt->rt_state, new, 0); 858 /* If the route got worse, check for something better. 859 */ 860 if (new->rts_metric > rts->rts_metric) 861 rtswitch(rt, 0); 862 return; 863 } 864 865 /* This is an update for a spare route. 866 * Finished if the route is unchanged. 867 */ 868 if (rts->rts_gate == new->rts_gate 869 && rts->rts_metric == new->rts_metric 870 && rts->rts_tag == new->rts_tag) { 871 trace_upslot(rt, rts, new); 872 *rts = *new; 873 return; 874 } 875 /* Forget it if it has gone bad. 876 */ 877 if (new->rts_metric == HOPCNT_INFINITY) { 878 rts_delete(rt, rts); 879 return; 880 } 881 882 } else { 883 /* The update is for a route we know about, 884 * but not from a familiar router. 885 * 886 * Ignore the route if it points to us. 887 */ 888 if (n->n_nhop != 0 889 && 0 != ifwithaddr(n->n_nhop, 1, 0)) 890 return; 891 892 /* the loop above set rts0=worst spare */ 893 rts = rts0; 894 895 /* Save the route as a spare only if it has 896 * a better metric than our worst spare. 897 * This also ignores poisoned routes (those 898 * received with metric HOPCNT_INFINITY). 899 */ 900 if (new->rts_metric >= rts->rts_metric) 901 return; 902 } 903 904 trace_upslot(rt, rts, new); 905 *rts = *new; 906 907 /* try to switch to a better route */ 908 rtswitch(rt, rts); 909 } 910 911 912 static int /* 0 if bad */ 913 ck_passwd(struct interface *aifp, 914 struct rip *rip, 915 void *lim, 916 naddr from, 917 struct msg_limit *use_authp) 918 { 919 # define NA (rip->rip_auths) 920 struct netauth *na2; 921 struct auth *ap; 922 MD5_CTX md5_ctx; 923 u_char hash[RIP_AUTH_PW_LEN]; 924 int i, len; 925 926 927 if ((void *)NA >= lim || NA->a_family != RIP_AF_AUTH) { 928 msglim(use_authp, from, "missing password from %s", 929 naddr_ntoa(from)); 930 return 0; 931 } 932 933 /* accept any current (+/- 24 hours) password 934 */ 935 for (ap = aifp->int_auth, i = 0; i < MAX_AUTH_KEYS; i++, ap++) { 936 if (ap->type != NA->a_type 937 || (u_long)ap->start > (u_long)clk.tv_sec+DAY 938 || (u_long)ap->end+DAY < (u_long)clk.tv_sec) 939 continue; 940 941 if (NA->a_type == RIP_AUTH_PW) { 942 if (!memcmp(NA->au.au_pw, ap->key, RIP_AUTH_PW_LEN)) 943 return 1; 944 945 } else { 946 /* accept MD5 secret with the right key ID 947 */ 948 if (NA->au.a_md5.md5_keyid != ap->keyid) 949 continue; 950 951 len = ntohs(NA->au.a_md5.md5_pkt_len); 952 if ((len-sizeof(*rip)) % sizeof(*NA) != 0 953 || len != (char *)lim-(char*)rip-(int)sizeof(*NA)) { 954 msglim(use_authp, from, 955 "wrong MD5 RIPv2 packet length of %d" 956 " instead of %d from %s", 957 len, (int)((char *)lim-(char *)rip 958 -sizeof(*NA)), 959 naddr_ntoa(from)); 960 return 0; 961 } 962 na2 = (struct netauth *)((char *)rip+len); 963 964 /* Given a good hash value, these are not security 965 * problems so be generous and accept the routes, 966 * after complaining. 967 */ 968 if (TRACEPACKETS) { 969 if (NA->au.a_md5.md5_auth_len 970 != RIP_AUTH_MD5_LEN) 971 msglim(use_authp, from, 972 "unknown MD5 RIPv2 auth len %#x" 973 " instead of %#x from %s", 974 NA->au.a_md5.md5_auth_len, 975 RIP_AUTH_MD5_LEN, 976 naddr_ntoa(from)); 977 if (na2->a_family != RIP_AF_AUTH) 978 msglim(use_authp, from, 979 "unknown MD5 RIPv2 family %#x" 980 " instead of %#x from %s", 981 na2->a_family, RIP_AF_AUTH, 982 naddr_ntoa(from)); 983 if (na2->a_type != ntohs(1)) 984 msglim(use_authp, from, 985 "MD5 RIPv2 hash has %#x" 986 " instead of %#x from %s", 987 na2->a_type, ntohs(1), 988 naddr_ntoa(from)); 989 } 990 991 MD5Init(&md5_ctx); 992 MD5Update(&md5_ctx, (u_char *)rip, len); 993 MD5Update(&md5_ctx, ap->key, RIP_AUTH_MD5_LEN); 994 MD5Final(hash, &md5_ctx); 995 if (!memcmp(hash, na2->au.au_pw, sizeof(hash))) 996 return 1; 997 } 998 } 999 1000 msglim(use_authp, from, "bad password from %s", 1001 naddr_ntoa(from)); 1002 return 0; 1003 #undef NA 1004 } 1005