1 /* $NetBSD: input.c,v 1.25 1999/02/23 10:47:40 christos Exp $ */ 2 3 /* 4 * Copyright (c) 1983, 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 acknowledgment: 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 36 #if !defined(lint) && !defined(sgi) && !defined(__NetBSD__) 37 static char sccsid[] __attribute__((unused)) = "@(#)input.c 8.1 (Berkeley) 6/5/93"; 38 #elif defined(__NetBSD__) 39 #include <sys/cdefs.h> 40 __RCSID("$NetBSD: input.c,v 1.25 1999/02/23 10:47:40 christos Exp $"); 41 #endif 42 43 #include "defs.h" 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 fromlen, cc; 61 #ifdef USE_PASSIFNAME 62 static struct msg_limit bad_name; 63 struct { 64 char ifname[IFNAMSIZ]; 65 union pkt_buf pbuf; 66 } inbuf; 67 #else 68 struct { 69 union pkt_buf pbuf; 70 } inbuf; 71 #endif 72 73 74 for (;;) { 75 fromlen = sizeof(from); 76 cc = recvfrom(sock, &inbuf, sizeof(inbuf), 0, 77 (struct sockaddr*)&from, &fromlen); 78 if (cc <= 0) { 79 if (cc < 0 && errno != EWOULDBLOCK) 80 LOGERR("recvfrom(rip)"); 81 break; 82 } 83 if (fromlen != sizeof(struct sockaddr_in)) 84 logbad(1,"impossible recvfrom(rip) fromlen=%d", 85 fromlen); 86 87 /* aifp is the "authenticated" interface via which the packet 88 * arrived. In fact, it is only the interface on which 89 * the packet should have arrived based on is source 90 * address. 91 * sifp is interface associated with the socket through which 92 * the packet was received. 93 */ 94 #ifdef USE_PASSIFNAME 95 if ((cc -= sizeof(inbuf.ifname)) < 0) 96 logbad(0,"missing USE_PASSIFNAME; only %d bytes", 97 cc+sizeof(inbuf.ifname)); 98 99 /* check the remote interfaces first */ 100 for (aifp = remote_if; aifp; aifp = aifp->int_rlink) { 101 if (aifp->int_addr == from.sin_addr.s_addr) 102 break; 103 } 104 if (aifp == 0) { 105 aifp = ifwithname(inbuf.ifname, 0); 106 if (aifp == 0) { 107 msglim(&bad_name, from.sin_addr.s_addr, 108 "impossible interface name %.*s", 109 IFNAMSIZ, inbuf.ifname); 110 } else if (((aifp->int_if_flags & IFF_POINTOPOINT) 111 && aifp->int_dstaddr!=from.sin_addr.s_addr) 112 || (!(aifp->int_if_flags & IFF_POINTOPOINT) 113 && !on_net(from.sin_addr.s_addr, 114 aifp->int_net, 115 aifp->int_mask))) { 116 /* If it came via the wrong interface, do not 117 * trust it. 118 */ 119 aifp = 0; 120 } 121 } 122 #else 123 aifp = iflookup(from.sin_addr.s_addr); 124 #endif 125 if (sifp == 0) 126 sifp = aifp; 127 128 input(&from, sifp, aifp, &inbuf.pbuf.rip, cc); 129 } 130 } 131 132 133 /* Process a RIP packet 134 */ 135 static void 136 input(struct sockaddr_in *from, /* received from this IP address */ 137 struct interface *sifp, /* interface of incoming socket */ 138 struct interface *aifp, /* "authenticated" interface */ 139 struct rip *rip, 140 int cc) 141 { 142 # define FROM_NADDR from->sin_addr.s_addr 143 static struct msg_limit use_auth, bad_len, bad_mask; 144 static struct msg_limit unk_router, bad_router, bad_nhop; 145 146 struct rt_entry *rt; 147 struct rt_spare new; 148 struct netinfo *n, *lim; 149 struct interface *ifp1; 150 naddr gate, mask, v1_mask, dst, ddst_h = 0; 151 struct auth *ap; 152 struct tgate *tg = 0; 153 struct tgate_net *tn; 154 int i, j; 155 156 /* Notice when we hear from a remote gateway 157 */ 158 if (aifp != 0 159 && (aifp->int_state & IS_REMOTE)) 160 aifp->int_act_time = now.tv_sec; 161 162 trace_rip("Recv", "from", from, sifp, rip, cc); 163 164 if (rip->rip_vers == 0) { 165 msglim(&bad_router, FROM_NADDR, 166 "RIP version 0, cmd %d, packet received from %s", 167 rip->rip_cmd, naddr_ntoa(FROM_NADDR)); 168 return; 169 } else if (rip->rip_vers > RIPv2) { 170 rip->rip_vers = RIPv2; 171 } 172 if (cc > (int)OVER_MAXPACKETSIZE) { 173 msglim(&bad_router, FROM_NADDR, 174 "packet at least %d bytes too long received from %s", 175 cc-MAXPACKETSIZE, naddr_ntoa(FROM_NADDR)); 176 return; 177 } 178 179 n = rip->rip_nets; 180 lim = (struct netinfo *)((char*)rip + cc); 181 182 /* Notice authentication. 183 * As required by section 4.2 in RFC 1723, discard authenticated 184 * RIPv2 messages, but only if configured for that silliness. 185 * 186 * RIPv2 authentication is lame. Why authenticate queries? 187 * Why should a RIPv2 implementation with authentication disabled 188 * not be able to listen to RIPv2 packets with authentication, while 189 * RIPv1 systems will listen? Crazy! 190 */ 191 if (!auth_ok 192 && rip->rip_vers == RIPv2 193 && n < lim && n->n_family == RIP_AF_AUTH) { 194 msglim(&use_auth, FROM_NADDR, 195 "RIPv2 message with authentication from %s discarded", 196 naddr_ntoa(FROM_NADDR)); 197 return; 198 } 199 200 switch (rip->rip_cmd) { 201 case RIPCMD_REQUEST: 202 /* For mere requests, be a little sloppy about the source 203 */ 204 if (aifp == 0) 205 aifp = sifp; 206 207 /* Are we talking to ourself or a remote gateway? 208 */ 209 ifp1 = ifwithaddr(FROM_NADDR, 0, 1); 210 if (ifp1) { 211 if (ifp1->int_state & IS_REMOTE) { 212 /* remote gateway */ 213 aifp = ifp1; 214 if (check_remote(aifp)) { 215 aifp->int_act_time = now.tv_sec; 216 (void)if_ok(aifp, "remote "); 217 } 218 } else if (from->sin_port == htons(RIP_PORT)) { 219 trace_pkt(" discard our own RIP request"); 220 return; 221 } 222 } 223 224 /* did the request come from a router? 225 */ 226 if (from->sin_port == htons(RIP_PORT)) { 227 /* yes, ignore the request if RIP is off so that 228 * the router does not depend on us. 229 */ 230 if (rip_sock < 0 231 || (aifp != 0 232 && IS_RIP_OUT_OFF(aifp->int_state))) { 233 trace_pkt(" discard request while RIP off"); 234 return; 235 } 236 } 237 238 /* According to RFC 1723, we should ignore unauthenticated 239 * queries. That is too silly to bother with. Sheesh! 240 * Are forwarding tables supposed to be secret, when 241 * a bad guy can infer them with test traffic? When RIP 242 * is still the most common router-discovery protocol 243 * and so hosts need to send queries that will be answered? 244 * What about `rtquery`? 245 * Maybe on firewalls you'd care, but not enough to 246 * give up the diagnostic facilities of remote probing. 247 */ 248 249 if (n >= lim) { 250 msglim(&bad_len, FROM_NADDR, "empty request from %s", 251 naddr_ntoa(FROM_NADDR)); 252 return; 253 } 254 if (cc%sizeof(*n) != sizeof(struct rip)%sizeof(*n)) { 255 msglim(&bad_len, FROM_NADDR, 256 "request of bad length (%d) from %s", 257 cc, naddr_ntoa(FROM_NADDR)); 258 } 259 260 if (rip->rip_vers == RIPv2 261 && (aifp == 0 || (aifp->int_state & IS_NO_RIPV1_OUT))) { 262 v12buf.buf->rip_vers = RIPv2; 263 /* If we have a secret but it is a cleartext secret, 264 * do not disclose our secret unless the other guy 265 * already knows it. 266 */ 267 ap = find_auth(aifp); 268 if (ap != 0 && ap->type == RIP_AUTH_PW 269 && n->n_family == RIP_AF_AUTH 270 && !ck_passwd(aifp,rip,lim,FROM_NADDR,&use_auth)) 271 ap = 0; 272 } else { 273 v12buf.buf->rip_vers = RIPv1; 274 ap = 0; 275 } 276 clr_ws_buf(&v12buf, ap); 277 278 do { 279 NTOHL(n->n_metric); 280 281 /* A single entry with family RIP_AF_UNSPEC and 282 * metric HOPCNT_INFINITY means "all routes". 283 * We respond to routers only if we are acting 284 * as a supplier, or to anyone other than a router 285 * (i.e. a query). 286 */ 287 if (n->n_family == RIP_AF_UNSPEC 288 && n->n_metric == HOPCNT_INFINITY) { 289 /* Answer a query from a utility program 290 * with all we know. 291 */ 292 if (from->sin_port != htons(RIP_PORT)) { 293 supply(from, aifp, OUT_QUERY, 0, 294 rip->rip_vers, ap != 0); 295 return; 296 } 297 298 /* A router trying to prime its tables. 299 * Filter the answer in the about same way 300 * broadcasts are filtered. 301 * 302 * Only answer a router if we are a supplier 303 * to keep an unwary host that is just starting 304 * from picking us as a router. 305 */ 306 if (aifp == 0) { 307 trace_pkt("ignore distant router"); 308 return; 309 } 310 if (!supplier 311 || IS_RIP_OFF(aifp->int_state)) { 312 trace_pkt("ignore; not supplying"); 313 return; 314 } 315 316 /* Do not answer a RIPv1 router if 317 * we are sending RIPv2. But do offer 318 * poor man's router discovery. 319 */ 320 if ((aifp->int_state & IS_NO_RIPV1_OUT) 321 && rip->rip_vers == RIPv1) { 322 if (!(aifp->int_state & IS_PM_RDISC)) { 323 trace_pkt("ignore; sending RIPv2"); 324 return; 325 } 326 327 v12buf.n->n_family = RIP_AF_INET; 328 v12buf.n->n_dst = RIP_DEFAULT; 329 i = aifp->int_d_metric; 330 if (0 != (rt = rtget(RIP_DEFAULT, 0))) 331 i = MIN(i, (rt->rt_metric 332 +aifp->int_metric+1)); 333 v12buf.n->n_metric = htonl(i); 334 v12buf.n++; 335 break; 336 } 337 338 /* Respond with RIPv1 instead of RIPv2 if 339 * that is what we are broadcasting on the 340 * interface to keep the remote router from 341 * getting the wrong initial idea of the 342 * routes we send. 343 */ 344 supply(from, aifp, OUT_UNICAST, 0, 345 (aifp->int_state & IS_NO_RIPV1_OUT) 346 ? RIPv2 : RIPv1, 347 ap != 0); 348 return; 349 } 350 351 /* Ignore authentication */ 352 if (n->n_family == RIP_AF_AUTH) 353 continue; 354 355 if (n->n_family != RIP_AF_INET) { 356 msglim(&bad_router, FROM_NADDR, 357 "request from %s for unsupported" 358 " (af %d) %s", 359 naddr_ntoa(FROM_NADDR), 360 ntohs(n->n_family), 361 naddr_ntoa(n->n_dst)); 362 return; 363 } 364 365 /* We are being asked about a specific destination. 366 */ 367 dst = n->n_dst; 368 if (!check_dst(dst)) { 369 msglim(&bad_router, FROM_NADDR, 370 "bad queried destination %s from %s", 371 naddr_ntoa(dst), 372 naddr_ntoa(FROM_NADDR)); 373 return; 374 } 375 376 /* decide what mask was intended */ 377 if (rip->rip_vers == RIPv1 378 || 0 == (mask = ntohl(n->n_mask)) 379 || 0 != (ntohl(dst) & ~mask)) 380 mask = ripv1_mask_host(dst, aifp); 381 382 /* try to find the answer */ 383 rt = rtget(dst, mask); 384 if (!rt && dst != RIP_DEFAULT) 385 rt = rtfind(n->n_dst); 386 387 if (v12buf.buf->rip_vers != RIPv1) 388 v12buf.n->n_mask = mask; 389 if (rt == 0) { 390 /* we do not have the answer */ 391 v12buf.n->n_metric = HOPCNT_INFINITY; 392 } else { 393 /* we have the answer, so compute the 394 * right metric and next hop. 395 */ 396 v12buf.n->n_family = RIP_AF_INET; 397 v12buf.n->n_dst = dst; 398 v12buf.n->n_metric = (rt->rt_metric+1 399 + ((aifp!=0) 400 ? aifp->int_metric 401 : 1)); 402 if (v12buf.n->n_metric > HOPCNT_INFINITY) 403 v12buf.n->n_metric = HOPCNT_INFINITY; 404 if (v12buf.buf->rip_vers != RIPv1) { 405 v12buf.n->n_tag = rt->rt_tag; 406 v12buf.n->n_mask = mask; 407 if (aifp != 0 408 && on_net(rt->rt_gate, 409 aifp->int_net, 410 aifp->int_mask) 411 && rt->rt_gate != aifp->int_addr) 412 v12buf.n->n_nhop = rt->rt_gate; 413 } 414 } 415 HTONL(v12buf.n->n_metric); 416 417 /* Stop paying attention if we fill the output buffer. 418 */ 419 if (++v12buf.n >= v12buf.lim) 420 break; 421 } while (++n < lim); 422 423 /* Send the answer about specific routes. 424 */ 425 if (ap != 0 && ap->type == RIP_AUTH_MD5) 426 end_md5_auth(&v12buf, ap); 427 428 if (from->sin_port != htons(RIP_PORT)) { 429 /* query */ 430 (void)output(OUT_QUERY, from, aifp, 431 v12buf.buf, 432 ((char *)v12buf.n - (char*)v12buf.buf)); 433 } else if (supplier) { 434 (void)output(OUT_UNICAST, from, aifp, 435 v12buf.buf, 436 ((char *)v12buf.n - (char*)v12buf.buf)); 437 } else { 438 /* Only answer a router if we are a supplier 439 * to keep an unwary host that is just starting 440 * from picking us an a router. 441 */ 442 ; 443 } 444 return; 445 446 case RIPCMD_TRACEON: 447 case RIPCMD_TRACEOFF: 448 /* verify message came from a privileged port */ 449 if (ntohs(from->sin_port) > IPPORT_RESERVED) { 450 msglog("trace command from untrusted port on %s", 451 naddr_ntoa(FROM_NADDR)); 452 return; 453 } 454 if (aifp == 0) { 455 msglog("trace command from unknown router %s", 456 naddr_ntoa(FROM_NADDR)); 457 return; 458 } 459 if (rip->rip_cmd == RIPCMD_TRACEON) { 460 rip->rip_tracefile[cc-4] = '\0'; 461 #ifndef __NetBSD__ 462 set_tracefile((char*)rip->rip_tracefile, 463 "trace command: %s\n", 0); 464 #else 465 msglog("RIP_TRACEON for `%s' from %s ignored", 466 (char *) rip->rip_tracefile, 467 naddr_ntoa(FROM_NADDR)); 468 #endif 469 } else { 470 #ifndef __NetBSD__ 471 trace_off("tracing turned off by %s", 472 naddr_ntoa(FROM_NADDR)); 473 #else 474 msglog("RIP_TRACEOFF from %s ignored", 475 naddr_ntoa(FROM_NADDR)); 476 #endif 477 } 478 return; 479 480 case RIPCMD_RESPONSE: 481 if (cc%sizeof(*n) != sizeof(struct rip)%sizeof(*n)) { 482 msglim(&bad_len, FROM_NADDR, 483 "response of bad length (%d) from %s", 484 cc, naddr_ntoa(FROM_NADDR)); 485 } 486 487 /* verify message came from a router */ 488 if (from->sin_port != ntohs(RIP_PORT)) { 489 msglim(&bad_router, FROM_NADDR, 490 " discard RIP response from unknown port" 491 " %d", from->sin_port); 492 return; 493 } 494 495 if (rip_sock < 0) { 496 trace_pkt(" discard response while RIP off"); 497 return; 498 } 499 500 /* Are we talking to ourself or a remote gateway? 501 */ 502 ifp1 = ifwithaddr(FROM_NADDR, 0, 1); 503 if (ifp1) { 504 if (ifp1->int_state & IS_REMOTE) { 505 /* remote gateway */ 506 aifp = ifp1; 507 if (check_remote(aifp)) { 508 aifp->int_act_time = now.tv_sec; 509 (void)if_ok(aifp, "remote "); 510 } 511 } else { 512 trace_pkt(" discard our own RIP response"); 513 return; 514 } 515 } 516 517 /* Accept routing packets from routers directly connected 518 * via broadcast or point-to-point networks, and from 519 * those listed in /etc/gateways. 520 */ 521 if (aifp == 0) { 522 msglim(&unk_router, FROM_NADDR, 523 " discard response from %s" 524 " via unexpected interface", 525 naddr_ntoa(FROM_NADDR)); 526 return; 527 } 528 if (IS_RIP_IN_OFF(aifp->int_state)) { 529 trace_pkt(" discard RIPv%d response" 530 " via disabled interface %s", 531 rip->rip_vers, aifp->int_name); 532 return; 533 } 534 535 if (n >= lim) { 536 msglim(&bad_len, FROM_NADDR, "empty response from %s", 537 naddr_ntoa(FROM_NADDR)); 538 return; 539 } 540 541 if (((aifp->int_state & IS_NO_RIPV1_IN) 542 && rip->rip_vers == RIPv1) 543 || ((aifp->int_state & IS_NO_RIPV2_IN) 544 && rip->rip_vers != RIPv1)) { 545 trace_pkt(" discard RIPv%d response", 546 rip->rip_vers); 547 return; 548 } 549 550 /* Ignore routes via dead interface. 551 */ 552 if (aifp->int_state & IS_BROKE) { 553 trace_pkt("discard response via broken interface %s", 554 aifp->int_name); 555 return; 556 } 557 558 /* If the interface cares, ignore bad routers. 559 * Trace but do not log this problem, because where it 560 * happens, it happens frequently. 561 */ 562 if (aifp->int_state & IS_DISTRUST) { 563 tg = tgates; 564 while (tg->tgate_addr != FROM_NADDR) { 565 tg = tg->tgate_next; 566 if (tg == 0) { 567 trace_pkt(" discard RIP response" 568 " from untrusted router %s", 569 naddr_ntoa(FROM_NADDR)); 570 return; 571 } 572 } 573 } 574 575 /* Authenticate the packet if we have a secret. 576 * If we do not have any secrets, ignore the error in 577 * RFC 1723 and accept it regardless. 578 */ 579 if (aifp->int_auth[0].type != RIP_AUTH_NONE 580 && rip->rip_vers != RIPv1 581 && !ck_passwd(aifp,rip,lim,FROM_NADDR,&use_auth)) 582 return; 583 584 do { 585 if (n->n_family == RIP_AF_AUTH) 586 continue; 587 588 NTOHL(n->n_metric); 589 dst = n->n_dst; 590 if (n->n_family != RIP_AF_INET 591 && (n->n_family != RIP_AF_UNSPEC 592 || dst != RIP_DEFAULT)) { 593 msglim(&bad_router, FROM_NADDR, 594 "route from %s to unsupported" 595 " address family=%d destination=%s", 596 naddr_ntoa(FROM_NADDR), 597 n->n_family, 598 naddr_ntoa(dst)); 599 continue; 600 } 601 if (!check_dst(dst)) { 602 msglim(&bad_router, FROM_NADDR, 603 "bad destination %s from %s", 604 naddr_ntoa(dst), 605 naddr_ntoa(FROM_NADDR)); 606 return; 607 } 608 if (n->n_metric == 0 609 || n->n_metric > HOPCNT_INFINITY) { 610 msglim(&bad_router, FROM_NADDR, 611 "bad metric %d from %s" 612 " for destination %s", 613 n->n_metric, 614 naddr_ntoa(FROM_NADDR), 615 naddr_ntoa(dst)); 616 return; 617 } 618 619 /* Notice the next-hop. 620 */ 621 gate = FROM_NADDR; 622 if (n->n_nhop != 0) { 623 if (rip->rip_vers == RIPv1) { 624 n->n_nhop = 0; 625 } else { 626 /* Use it only if it is valid. */ 627 if (on_net(n->n_nhop, 628 aifp->int_net, aifp->int_mask) 629 && check_dst(n->n_nhop)) { 630 gate = n->n_nhop; 631 } else { 632 msglim(&bad_nhop, FROM_NADDR, 633 "router %s to %s" 634 " has bad next hop %s", 635 naddr_ntoa(FROM_NADDR), 636 naddr_ntoa(dst), 637 naddr_ntoa(n->n_nhop)); 638 n->n_nhop = 0; 639 } 640 } 641 } 642 643 if (rip->rip_vers == RIPv1 644 || 0 == (mask = ntohl(n->n_mask))) { 645 mask = ripv1_mask_host(dst,aifp); 646 } else if ((ntohl(dst) & ~mask) != 0) { 647 msglim(&bad_mask, FROM_NADDR, 648 "router %s sent bad netmask" 649 " %#lx with %s", 650 naddr_ntoa(FROM_NADDR), 651 (u_long)mask, 652 naddr_ntoa(dst)); 653 continue; 654 } 655 if (rip->rip_vers == RIPv1) 656 n->n_tag = 0; 657 658 /* Adjust metric according to incoming interface.. 659 */ 660 n->n_metric += aifp->int_metric; 661 if (n->n_metric > HOPCNT_INFINITY) 662 n->n_metric = HOPCNT_INFINITY; 663 664 /* Should we trust this route from this router? */ 665 if (tg && (tn = tg->tgate_nets)->mask != 0) { 666 for (i = 0; i < MAX_TGATE_NETS; i++, tn++) { 667 if (on_net(dst, tn->net, tn->mask) 668 && tn->mask <= mask) 669 break; 670 } 671 if (i >= MAX_TGATE_NETS || tn->mask == 0) { 672 trace_pkt(" ignored unauthorized %s", 673 addrname(dst,mask,0)); 674 continue; 675 } 676 } 677 678 /* Recognize and ignore a default route we faked 679 * which is being sent back to us by a machine with 680 * broken split-horizon. 681 * Be a little more paranoid than that, and reject 682 * default routes with the same metric we advertised. 683 */ 684 if (aifp->int_d_metric != 0 685 && dst == RIP_DEFAULT 686 && (int)n->n_metric >= aifp->int_d_metric) 687 continue; 688 689 /* We can receive aggregated RIPv2 routes that must 690 * be broken down before they are transmitted by 691 * RIPv1 via an interface on a subnet. 692 * We might also receive the same routes aggregated 693 * via other RIPv2 interfaces. 694 * This could cause duplicate routes to be sent on 695 * the RIPv1 interfaces. "Longest matching variable 696 * length netmasks" lets RIPv2 listeners understand, 697 * but breaking down the aggregated routes for RIPv1 698 * listeners can produce duplicate routes. 699 * 700 * Breaking down aggregated routes here bloats 701 * the daemon table, but does not hurt the kernel 702 * table, since routes are always aggregated for 703 * the kernel. 704 * 705 * Notice that this does not break down network 706 * routes corresponding to subnets. This is part 707 * of the defense against RS_NET_SYN. 708 */ 709 if (have_ripv1_out 710 && (((rt = rtget(dst,mask)) == 0 711 || !(rt->rt_state & RS_NET_SYN))) 712 && (v1_mask = ripv1_mask_net(dst,0)) > mask) { 713 ddst_h = v1_mask & -v1_mask; 714 i = (v1_mask & ~mask)/ddst_h; 715 if (i >= 511) { 716 /* Punt if we would have to generate 717 * an unreasonable number of routes. 718 */ 719 if (TRACECONTENTS) 720 trace_misc("accept %s-->%s as 1" 721 " instead of %d routes", 722 addrname(dst,mask,0), 723 naddr_ntoa(FROM_NADDR), 724 i+1); 725 i = 0; 726 } else { 727 mask = v1_mask; 728 } 729 } else { 730 i = 0; 731 } 732 733 new.rts_gate = gate; 734 new.rts_router = FROM_NADDR; 735 new.rts_metric = n->n_metric; 736 new.rts_tag = n->n_tag; 737 new.rts_time = now.tv_sec; 738 new.rts_ifp = aifp; 739 new.rts_de_ag = i; 740 j = 0; 741 for (;;) { 742 input_route(dst, mask, &new, n); 743 if (++j > i) 744 break; 745 dst = htonl(ntohl(dst) + ddst_h); 746 } 747 } while (++n < lim); 748 break; 749 } 750 #undef FROM_NADDR 751 } 752 753 754 /* Process a single input route. 755 */ 756 static void 757 input_route(naddr dst, /* network order */ 758 naddr mask, 759 struct rt_spare *new, 760 struct netinfo *n) 761 { 762 int i; 763 struct rt_entry *rt; 764 struct rt_spare *rts, *rts0; 765 struct interface *ifp1; 766 767 768 /* See if the other guy is telling us to send our packets to him. 769 * Sometimes network routes arrive over a point-to-point link for 770 * the network containing the address(es) of the link. 771 * 772 * If our interface is broken, switch to using the other guy. 773 */ 774 ifp1 = ifwithaddr(dst, 1, 1); 775 if (ifp1 != 0 776 && (!(ifp1->int_state & IS_BROKE) 777 || (ifp1->int_state & IS_PASSIVE))) 778 return; 779 780 /* Look for the route in our table. 781 */ 782 rt = rtget(dst, mask); 783 784 /* Consider adding the route if we do not already have it. 785 */ 786 if (rt == 0) { 787 /* Ignore unknown routes being poisoned. 788 */ 789 if (new->rts_metric == HOPCNT_INFINITY) 790 return; 791 792 /* Ignore the route if it points to us */ 793 if (n->n_nhop != 0 794 && 0 != ifwithaddr(n->n_nhop, 1, 0)) 795 return; 796 797 /* If something has not gone crazy and tried to fill 798 * our memory, accept the new route. 799 */ 800 if (total_routes < MAX_ROUTES) 801 rtadd(dst, mask, 0, new); 802 return; 803 } 804 805 /* We already know about the route. Consider this update. 806 * 807 * If (rt->rt_state & RS_NET_SYN), then this route 808 * is the same as a network route we have inferred 809 * for subnets we know, in order to tell RIPv1 routers 810 * about the subnets. 811 * 812 * It is impossible to tell if the route is coming 813 * from a distant RIPv2 router with the standard 814 * netmask because that router knows about the entire 815 * network, or if it is a round-about echo of a 816 * synthetic, RIPv1 network route of our own. 817 * The worst is that both kinds of routes might be 818 * received, and the bad one might have the smaller 819 * metric. Partly solve this problem by never 820 * aggregating into such a route. Also keep it 821 * around as long as the interface exists. 822 */ 823 824 rts0 = rt->rt_spares; 825 for (rts = rts0, i = NUM_SPARES; i != 0; i--, rts++) { 826 if (rts->rts_router == new->rts_router) 827 break; 828 /* Note the worst slot to reuse, 829 * other than the current slot. 830 */ 831 if (rts0 == rt->rt_spares 832 || BETTER_LINK(rt, rts0, rts)) 833 rts0 = rts; 834 } 835 if (i != 0) { 836 /* Found a route from the router already in the table. 837 */ 838 839 /* If the new route is a route broken down from an 840 * aggregated route, and if the previous route is either 841 * not a broken down route or was broken down from a finer 842 * netmask, and if the previous route is current, 843 * then forget this one. 844 */ 845 if (new->rts_de_ag > rts->rts_de_ag 846 && now_stale <= rts->rts_time) 847 return; 848 849 /* Keep poisoned routes around only long enough to pass 850 * the poison on. Use a new timestamp for good routes. 851 */ 852 if (rts->rts_metric == HOPCNT_INFINITY 853 && new->rts_metric == HOPCNT_INFINITY) 854 new->rts_time = rts->rts_time; 855 856 /* If this is an update for the router we currently prefer, 857 * then note it. 858 */ 859 if (i == NUM_SPARES) { 860 rtchange(rt, rt->rt_state, new, 0); 861 /* If the route got worse, check for something better. 862 */ 863 if (new->rts_metric > rts->rts_metric) 864 rtswitch(rt, 0); 865 return; 866 } 867 868 /* This is an update for a spare route. 869 * Finished if the route is unchanged. 870 */ 871 if (rts->rts_gate == new->rts_gate 872 && rts->rts_metric == new->rts_metric 873 && rts->rts_tag == new->rts_tag) { 874 trace_upslot(rt, rts, new); 875 *rts = *new; 876 return; 877 } 878 /* Forget it if it has gone bad. 879 */ 880 if (new->rts_metric == HOPCNT_INFINITY) { 881 rts_delete(rt, rts); 882 return; 883 } 884 885 } else { 886 /* The update is for a route we know about, 887 * but not from a familiar router. 888 * 889 * Ignore the route if it points to us. 890 */ 891 if (n->n_nhop != 0 892 && 0 != ifwithaddr(n->n_nhop, 1, 0)) 893 return; 894 895 /* the loop above set rts0=worst spare */ 896 rts = rts0; 897 898 /* Save the route as a spare only if it has 899 * a better metric than our worst spare. 900 * This also ignores poisoned routes (those 901 * received with metric HOPCNT_INFINITY). 902 */ 903 if (new->rts_metric >= rts->rts_metric) 904 return; 905 } 906 907 trace_upslot(rt, rts, new); 908 *rts = *new; 909 910 /* try to switch to a better route */ 911 rtswitch(rt, rts); 912 } 913 914 915 static int /* 0 if bad */ 916 ck_passwd(struct interface *aifp, 917 struct rip *rip, 918 void *lim, 919 naddr from, 920 struct msg_limit *use_authp) 921 { 922 # define NA (rip->rip_auths) 923 struct netauth *na2; 924 struct auth *ap; 925 MD5_CTX md5_ctx; 926 u_char hash[RIP_AUTH_PW_LEN]; 927 int i, len; 928 929 930 if ((void *)NA >= lim || NA->a_family != RIP_AF_AUTH) { 931 msglim(use_authp, from, "missing password from %s", 932 naddr_ntoa(from)); 933 return 0; 934 } 935 936 /* accept any current (+/- 24 hours) password 937 */ 938 for (ap = aifp->int_auth, i = 0; i < MAX_AUTH_KEYS; i++, ap++) { 939 if (ap->type != NA->a_type 940 || (u_long)ap->start > (u_long)clk.tv_sec+DAY 941 || (u_long)ap->end+DAY < (u_long)clk.tv_sec) 942 continue; 943 944 if (NA->a_type == RIP_AUTH_PW) { 945 if (!memcmp(NA->au.au_pw, ap->key, RIP_AUTH_PW_LEN)) 946 return 1; 947 948 } else { 949 /* accept MD5 secret with the right key ID 950 */ 951 if (NA->au.a_md5.md5_keyid != ap->keyid) 952 continue; 953 954 len = ntohs(NA->au.a_md5.md5_pkt_len); 955 if ((len-sizeof(*rip)) % sizeof(*NA) != 0 956 || len != (char *)lim-(char*)rip-(int)sizeof(*NA)) { 957 msglim(use_authp, from, 958 "wrong MD5 RIPv2 packet length of %d" 959 " instead of %d from %s", 960 len, (int)((char *)lim-(char *)rip 961 -sizeof(*NA)), 962 naddr_ntoa(from)); 963 return 0; 964 } 965 na2 = (struct netauth *)((char *)rip+len); 966 967 /* Given a good hash value, these are not security 968 * problems so be generous and accept the routes, 969 * after complaining. 970 */ 971 if (TRACEPACKETS) { 972 if (NA->au.a_md5.md5_auth_len 973 != RIP_AUTH_MD5_LEN) 974 msglim(use_authp, from, 975 "unknown MD5 RIPv2 auth len %#x" 976 " instead of %#x from %s", 977 NA->au.a_md5.md5_auth_len, 978 RIP_AUTH_MD5_LEN, 979 naddr_ntoa(from)); 980 if (na2->a_family != RIP_AF_AUTH) 981 msglim(use_authp, from, 982 "unknown MD5 RIPv2 family %#x" 983 " instead of %#x from %s", 984 na2->a_family, RIP_AF_AUTH, 985 naddr_ntoa(from)); 986 if (na2->a_type != ntohs(1)) 987 msglim(use_authp, from, 988 "MD5 RIPv2 hash has %#x" 989 " instead of %#x from %s", 990 na2->a_type, ntohs(1), 991 naddr_ntoa(from)); 992 } 993 994 MD5Init(&md5_ctx); 995 MD5Update(&md5_ctx, (u_char *)rip, len); 996 MD5Update(&md5_ctx, ap->key, RIP_AUTH_MD5_LEN); 997 MD5Final(hash, &md5_ctx); 998 if (!memcmp(hash, na2->au.au_pw, sizeof(hash))) 999 return 1; 1000 } 1001 } 1002 1003 msglim(use_authp, from, "bad password from %s", 1004 naddr_ntoa(from)); 1005 return 0; 1006 #undef NA 1007 } 1008