sbin/routed/output.c

   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/output.c,v 1.5.2.1 2000/08/14 17:00:03 sheldonh Exp $
  34  * $DragonFly: src/sbin/routed/output.c,v 1.5 2005/03/16 21:21:34 cpressey Exp $
  35  */
  36
  37 #include "defs.h"
  38
  39 #if !defined(sgi) && !defined(__NetBSD__)
  40 static char sccsid[] __attribute__((unused)) = "@(#)output.c    8.1 (Berkeley) 6/5/93";
  41 #elif defined(__NetBSD__)
  42 __RCSID("$NetBSD$");
  43 #endif
  44
  45
  46 u_int update_seqno;
  47
  48
  49 /* walk the tree of routes with this for output
  50  */
  51 struct {
  52         struct sockaddr_in to;
  53         naddr   to_mask;
  54         naddr   to_net;
  55         naddr   to_std_mask;
  56         naddr   to_std_net;
  57         struct interface *ifp;          /* usually output interface */
  58         struct auth *a;
  59         char    metric;                 /* adjust metrics by interface */
  60         int     npackets;
  61         int     gen_limit;
  62         u_int   state;
  63 #define     WS_ST_FLASH     0x001       /* send only changed routes */
  64 #define     WS_ST_RIP2_ALL  0x002       /* send full featured RIPv2 */
  65 #define     WS_ST_AG        0x004       /* ok to aggregate subnets */
  66 #define     WS_ST_SUPER_AG  0x008       /* ok to aggregate networks */
  67 #define     WS_ST_QUERY     0x010       /* responding to a query */
  68 #define     WS_ST_TO_ON_NET 0x020       /* sending onto one of our nets */
  69 #define     WS_ST_DEFAULT   0x040       /* faking a default */
  70 } ws;
  71
  72 /* A buffer for what can be heard by both RIPv1 and RIPv2 listeners */
  73 struct ws_buf v12buf;
  74 union pkt_buf ripv12_buf;
  75
  76 /* Another for only RIPv2 listeners */
  77 struct ws_buf v2buf;
  78 union pkt_buf rip_v2_buf;
  79
  80
  81
  82 void
  83 bufinit(void)
  84 {
  85         ripv12_buf.rip.rip_cmd = RIPCMD_RESPONSE;
  86         v12buf.buf = &ripv12_buf.rip;
  87         v12buf.base = &v12buf.buf->rip_nets[0];
  88
  89         rip_v2_buf.rip.rip_cmd = RIPCMD_RESPONSE;
  90         rip_v2_buf.rip.rip_vers = RIPv2;
  91         v2buf.buf = &rip_v2_buf.rip;
  92         v2buf.base = &v2buf.buf->rip_nets[0];
  93 }
  94
  95
  96 /* Send the contents of the global buffer via the non-multicast socket
  97  */
  98 int                                     /* <0 on failure */
  99 output(enum output_type type,
 100        struct sockaddr_in *dst,         /* send to here */
 101        struct interface *ifp,
 102        struct rip *buf,
 103        int size)                        /* this many bytes */
 104 {
 105         struct sockaddr_in in;
 106         int flags;
 107         const char *msg;
 108         int res;
 109         naddr tgt_mcast;
 110         int soc;
 111         int serrno;
 112
 113         in = *dst;
 114         if (in.sin_port == 0)
 115                 in.sin_port = htons(RIP_PORT);
 116 #ifdef _HAVE_SIN_LEN
 117         if (in.sin_len == 0)
 118                 in.sin_len = sizeof(in);
 119 #endif
 120
 121         soc = rip_sock;
 122         flags = 0;
 123
 124         switch (type) {
 125         case OUT_QUERY:
 126                 msg = "Answer Query";
 127                 if (soc < 0)
 128                         soc = ifp->int_rip_sock;
 129                 break;
 130         case OUT_UNICAST:
 131                 msg = "Send";
 132                 if (soc < 0)
 133                         soc = ifp->int_rip_sock;
 134                 flags = MSG_DONTROUTE;
 135                 break;
 136         case OUT_BROADCAST:
 137                 if (ifp->int_if_flags & IFF_POINTOPOINT) {
 138                         msg = "Send";
 139                 } else {
 140                         msg = "Send bcast";
 141                 }
 142                 flags = MSG_DONTROUTE;
 143                 break;
 144         case OUT_MULTICAST:
 145                 if (ifp->int_if_flags & IFF_POINTOPOINT) {
 146                         msg = "Send pt-to-pt";
 147                 } else if (ifp->int_state & IS_DUP) {
 148                         trace_act("abort multicast output via %s"
 149                                   " with duplicate address",
 150                                   ifp->int_name);
 151                         return 0;
 152                 } else {
 153                         msg = "Send mcast";
 154                         if (rip_sock_mcast != ifp) {
 155 #ifdef MCAST_PPP_BUG
 156                                 /* Do not specify the primary interface
 157                                  * explicitly if we have the multicast
 158                                  * point-to-point kernel bug, since the
 159                                  * kernel will do the wrong thing if the
 160                                  * local address of a point-to-point link
 161                                  * is the same as the address of an ordinary
 162                                  * interface.
 163                                  */
 164                                 if (ifp->int_addr == myaddr) {
 165                                         tgt_mcast = 0;
 166                                 } else
 167 #endif
 168                                 tgt_mcast = ifp->int_addr;
 169                                 if (0 > setsockopt(rip_sock,
 170                                                    IPPROTO_IP, IP_MULTICAST_IF,
 171                                                    &tgt_mcast,
 172                                                    sizeof(tgt_mcast))) {
 173                                         serrno = errno;
 174                                         LOGERR("setsockopt(rip_sock,"
 175                                                "IP_MULTICAST_IF)");
 176                                         errno = serrno;
 177                                         ifp = 0;
 178                                         return -1;
 179                                 }
 180                                 rip_sock_mcast = ifp;
 181                         }
 182                         in.sin_addr.s_addr = htonl(INADDR_RIP_GROUP);
 183                 }
 184                 break;
 185
 186         case NO_OUT_MULTICAST:
 187         case NO_OUT_RIPV2:
 188         default:
 189 #ifdef DEBUG
 190                 abort();
 191 #endif
 192                 return -1;
 193         }
 194
 195         trace_rip(msg, "to", &in, ifp, buf, size);
 196
 197         res = sendto(soc, buf, size, flags,
 198                      (struct sockaddr *)&in, sizeof(in));
 199         if (res < 0
 200             && (ifp == 0 || !(ifp->int_state & IS_BROKE))) {
 201                 serrno = errno;
 202                 msglog("%s sendto(%s%s%s.%d): %s", msg,
 203                        ifp != 0 ? ifp->int_name : "",
 204                        ifp != 0 ? ", " : "",
 205                        inet_ntoa(in.sin_addr),
 206                        ntohs(in.sin_port),
 207                        strerror(errno));
 208                 errno = serrno;
 209         }
 210
 211         return res;
 212 }
 213
 214
 215 /* Find the first key for a packet to send.
 216  * Try for a key that is eligible and has not expired, but settle for
 217  * the last key if they have all expired.
 218  * If no key is ready yet, give up.
 219  */
 220 struct auth *
 221 find_auth(struct interface *ifp)
 222 {
 223         struct auth *ap, *res;
 224         int i;
 225
 226
 227         if (ifp == 0)
 228                 return 0;
 229
 230         res = 0;
 231         ap = ifp->int_auth;
 232         for (i = 0; i < MAX_AUTH_KEYS; i++, ap++) {
 233                 /* stop looking after the last key */
 234                 if (ap->type == RIP_AUTH_NONE)
 235                         break;
 236
 237                 /* ignore keys that are not ready yet */
 238                 if ((u_long)ap->start > (u_long)clk.tv_sec)
 239                         continue;
 240
 241                 if ((u_long)ap->end < (u_long)clk.tv_sec) {
 242                         /* note best expired password as a fall-back */
 243                         if (res == 0 || (u_long)ap->end > (u_long)res->end)
 244                                 res = ap;
 245                         continue;
 246                 }
 247
 248                 /* note key with the best future */
 249                 if (res == 0 || (u_long)res->end < (u_long)ap->end)
 250                         res = ap;
 251         }
 252         return res;
 253 }
 254
 255
 256 void
 257 clr_ws_buf(struct ws_buf *wb,
 258            struct auth *ap)
 259 {
 260         struct netauth *na;
 261
 262         wb->lim = wb->base + NETS_LEN;
 263         wb->n = wb->base;
 264         memset(wb->n, 0, NETS_LEN*sizeof(*wb->n));
 265
 266         /* (start to) install authentication if appropriate
 267          */
 268         if (ap == 0)
 269                 return;
 270
 271         na = (struct netauth*)wb->n;
 272         if (ap->type == RIP_AUTH_PW) {
 273                 na->a_family = RIP_AF_AUTH;
 274                 na->a_type = RIP_AUTH_PW;
 275                 memcpy(na->au.au_pw, ap->key, sizeof(na->au.au_pw));
 276                 wb->n++;
 277
 278         } else if (ap->type ==  RIP_AUTH_MD5) {
 279                 na->a_family = RIP_AF_AUTH;
 280                 na->a_type = RIP_AUTH_MD5;
 281                 na->au.a_md5.md5_keyid = ap->keyid;
 282                 na->au.a_md5.md5_auth_len = RIP_AUTH_MD5_LEN;
 283                 na->au.a_md5.md5_seqno = htonl(clk.tv_sec);
 284                 wb->n++;
 285                 wb->lim--;              /* make room for trailer */
 286         }
 287 }
 288
 289
 290 void
 291 end_md5_auth(struct ws_buf *wb,
 292              struct auth *ap)
 293 {
 294         struct netauth *na, *na2;
 295         MD5_CTX md5_ctx;
 296         int len;
 297
 298
 299         na = (struct netauth*)wb->base;
 300         na2 = (struct netauth*)wb->n;
 301         len = (char *)na2-(char *)wb->buf;
 302         na2->a_family = RIP_AF_AUTH;
 303         na2->a_type = htons(1);
 304         na->au.a_md5.md5_pkt_len = htons(len);
 305         MD5Init(&md5_ctx);
 306         MD5Update(&md5_ctx, (u_char *)wb->buf, len);
 307         MD5Update(&md5_ctx, ap->key, RIP_AUTH_MD5_LEN);
 308         MD5Final(na2->au.au_pw, &md5_ctx);
 309         wb->n++;
 310 }
 311
 312
 313 /* Send the buffer
 314  */
 315 static void
 316 supply_write(struct ws_buf *wb)
 317 {
 318         /* Output multicast only if legal.
 319          * If we would multicast and it would be illegal, then discard the
 320          * packet.
 321          */
 322         switch (wb->type) {
 323         case NO_OUT_MULTICAST:
 324                 trace_pkt("skip multicast to %s because impossible",
 325                           naddr_ntoa(ws.to.sin_addr.s_addr));
 326                 break;
 327         case NO_OUT_RIPV2:
 328                 break;
 329         default:
 330                 if (ws.a != 0 && ws.a->type == RIP_AUTH_MD5)
 331                         end_md5_auth(wb,ws.a);
 332                 if (output(wb->type, &ws.to, ws.ifp, wb->buf,
 333                            ((char *)wb->n - (char*)wb->buf)) < 0
 334                     && ws.ifp != 0)
 335                         if_sick(ws.ifp);
 336                 ws.npackets++;
 337                 break;
 338         }
 339
 340         clr_ws_buf(wb,ws.a);
 341 }
 342
 343
 344 /* put an entry into the packet
 345  */
 346 static void
 347 supply_out(struct ag_info *ag)
 348 {
 349         int i;
 350         naddr mask, v1_mask, dst_h, ddst_h = 0;
 351         struct ws_buf *wb;
 352
 353
 354         /* Skip this route if doing a flash update and it and the routes
 355          * it aggregates have not changed recently.
 356          */
 357         if (ag->ag_seqno < update_seqno
 358             && (ws.state & WS_ST_FLASH))
 359                 return;
 360
 361         dst_h = ag->ag_dst_h;
 362         mask = ag->ag_mask;
 363         v1_mask = ripv1_mask_host(htonl(dst_h),
 364                                   (ws.state & WS_ST_TO_ON_NET) ? ws.ifp : 0);
 365         i = 0;
 366
 367         /* If we are sending RIPv2 packets that cannot (or must not) be
 368          * heard by RIPv1 listeners, do not worry about sub- or supernets.
 369          * Subnets (from other networks) can only be sent via multicast.
 370          * A pair of subnet routes might have been promoted so that they
 371          * are legal to send by RIPv1.
 372          * If RIPv1 is off, use the multicast buffer.
 373          */
 374         if ((ws.state & WS_ST_RIP2_ALL)
 375             || ((ag->ag_state & AGS_RIPV2) && v1_mask != mask)) {
 376                 /* use the RIPv2-only buffer */
 377                 wb = &v2buf;
 378
 379         } else {
 380                 /* use the RIPv1-or-RIPv2 buffer */
 381                 wb = &v12buf;
 382
 383                 /* Convert supernet route into corresponding set of network
 384                  * routes for RIPv1, but leave non-contiguous netmasks
 385                  * to ag_check().
 386                  */
 387                 if (v1_mask > mask
 388                     && mask + (mask & -mask) == 0) {
 389                         ddst_h = v1_mask & -v1_mask;
 390                         i = (v1_mask & ~mask)/ddst_h;
 391
 392                         if (i > ws.gen_limit) {
 393                                 /* Punt if we would have to generate an
 394                                  * unreasonable number of routes.
 395                                  */
 396                                 if (TRACECONTENTS)
 397                                         trace_misc("sending %s-->%s as 1"
 398                                                    " instead of %d routes",
 399                                                    addrname(htonl(dst_h), mask,
 400                                                         1),
 401                                                    naddr_ntoa(ws.to.sin_addr
 402                                                         .s_addr),
 403                                                    i+1);
 404                                 i = 0;
 405
 406                         } else {
 407                                 mask = v1_mask;
 408                                 ws.gen_limit -= i;
 409                         }
 410                 }
 411         }
 412
 413         do {
 414                 wb->n->n_family = RIP_AF_INET;
 415                 wb->n->n_dst = htonl(dst_h);
 416                 /* If the route is from router-discovery or we are
 417                  * shutting down, admit only a bad metric.
 418                  */
 419                 wb->n->n_metric = ((stopint || ag->ag_metric < 1)
 420                                    ? HOPCNT_INFINITY
 421                                    : ag->ag_metric);
 422                 wb->n->n_metric = htonl(wb->n->n_metric);
 423                 /* Any non-zero bits in the supposedly unused RIPv1 fields
 424                  * cause the old `routed` to ignore the route.
 425                  * That means the mask and so forth cannot be sent
 426                  * in the hybrid RIPv1/RIPv2 mode.
 427                  */
 428                 if (ws.state & WS_ST_RIP2_ALL) {
 429                         if (ag->ag_nhop != 0
 430                             && ((ws.state & WS_ST_QUERY)
 431                                 || (ag->ag_nhop != ws.ifp->int_addr
 432                                     && on_net(ag->ag_nhop,
 433                                               ws.ifp->int_net,
 434                                               ws.ifp->int_mask))))
 435                                 wb->n->n_nhop = ag->ag_nhop;
 436                         wb->n->n_mask = htonl(mask);
 437                         wb->n->n_tag = ag->ag_tag;
 438                 }
 439                 dst_h += ddst_h;
 440
 441                 if (++wb->n >= wb->lim)
 442                         supply_write(wb);
 443         } while (i-- != 0);
 444 }
 445
 446
 447 /* supply one route from the table
 448  */
 449 /* ARGSUSED */
 450 static int
 451 walk_supply(struct radix_node *rn,
 452             struct walkarg *argp UNUSED)
 453 {
 454 #define RT ((struct rt_entry *)rn)
 455         u_short ags;
 456         char metric, pref;
 457         naddr dst, nhop;
 458         struct rt_spare *rts;
 459         int i;
 460
 461
 462         /* Do not advertise external remote interfaces or passive interfaces.
 463          */
 464         if ((RT->rt_state & RS_IF)
 465             && RT->rt_ifp != 0
 466             && (RT->rt_ifp->int_state & IS_PASSIVE)
 467             && !(RT->rt_state & RS_MHOME))
 468                 return 0;
 469
 470         /* If being quiet about our ability to forward, then
 471          * do not say anything unless responding to a query,
 472          * except about our main interface.
 473          */
 474         if (!supplier && !(ws.state & WS_ST_QUERY)
 475             && !(RT->rt_state & RS_MHOME))
 476                 return 0;
 477
 478         dst = RT->rt_dst;
 479
 480         /* do not collide with the fake default route */
 481         if (dst == RIP_DEFAULT
 482             && (ws.state & WS_ST_DEFAULT))
 483                 return 0;
 484
 485         if (RT->rt_state & RS_NET_SYN) {
 486                 if (RT->rt_state & RS_NET_INT) {
 487                         /* Do not send manual synthetic network routes
 488                          * into the subnet.
 489                          */
 490                         if (on_net(ws.to.sin_addr.s_addr,
 491                                    ntohl(dst), RT->rt_mask))
 492                                 return 0;
 493
 494                 } else {
 495                         /* Do not send automatic synthetic network routes
 496                          * if they are not needed because no RIPv1 listeners
 497                          * can hear them.
 498                          */
 499                         if (ws.state & WS_ST_RIP2_ALL)
 500                                 return 0;
 501
 502                         /* Do not send automatic synthetic network routes to
 503                          * the real subnet.
 504                          */
 505                         if (on_net(ws.to.sin_addr.s_addr,
 506                                    ntohl(dst), RT->rt_mask))
 507                                 return 0;
 508                 }
 509                 nhop = 0;
 510
 511         } else {
 512                 /* Advertise the next hop if this is not a route for one
 513                  * of our interfaces and the next hop is on the same
 514                  * network as the target.
 515                  * The final determination is made by supply_out().
 516                  */
 517                 if (!(RT->rt_state & RS_IF)
 518                     && RT->rt_gate != myaddr
 519                     && RT->rt_gate != loopaddr)
 520                         nhop = RT->rt_gate;
 521                 else
 522                         nhop = 0;
 523         }
 524
 525         metric = RT->rt_metric;
 526         ags = 0;
 527
 528         if (RT->rt_state & RS_MHOME) {
 529                 /* retain host route of multi-homed servers */
 530                 ;
 531
 532         } else if (RT_ISHOST(RT)) {
 533                 /* We should always suppress (into existing network routes)
 534                  * the host routes for the local end of our point-to-point
 535                  * links.
 536                  * If we are suppressing host routes in general, then do so.
 537                  * Avoid advertising host routes onto their own network,
 538                  * where they should be handled by proxy-ARP.
 539                  */
 540                 if ((RT->rt_state & RS_LOCAL)
 541                     || ridhosts
 542                     || on_net(dst, ws.to_net, ws.to_mask))
 543                         ags |= AGS_SUPPRESS;
 544
 545                 /* Aggregate stray host routes into network routes if allowed.
 546                  * We cannot aggregate host routes into small network routes
 547                  * without confusing RIPv1 listeners into thinking the
 548                  * network routes are host routes.
 549                  */
 550                 if ((ws.state & WS_ST_AG)
 551                     && !(ws.state & WS_ST_RIP2_ALL))
 552                         ags |= AGS_AGGREGATE;
 553
 554         } else {
 555                 /* Always suppress network routes into other, existing
 556                  * network routes
 557                  */
 558                 ags |= AGS_SUPPRESS;
 559
 560                 /* Generate supernets if allowed.
 561                  * If we can be heard by RIPv1 systems, we will
 562                  * later convert back to ordinary nets.
 563                  * This unifies dealing with received supernets.
 564                  */
 565                 if ((ws.state & WS_ST_AG)
 566                     && ((RT->rt_state & RS_SUBNET)
 567                         || (ws.state & WS_ST_SUPER_AG)))
 568                         ags |= AGS_AGGREGATE;
 569         }
 570
 571         /* Do not send RIPv1 advertisements of subnets to other
 572          * networks. If possible, multicast them by RIPv2.
 573          */
 574         if ((RT->rt_state & RS_SUBNET)
 575             && !(ws.state & WS_ST_RIP2_ALL)
 576             && !on_net(dst, ws.to_std_net, ws.to_std_mask))
 577                 ags |= AGS_RIPV2 | AGS_AGGREGATE;
 578
 579
 580         /* Do not send a route back to where it came from, except in
 581          * response to a query.  This is "split-horizon".  That means not
 582          * advertising back to the same network and so via the same interface.
 583          *
 584          * We want to suppress routes that might have been fragmented
 585          * from this route by a RIPv1 router and sent back to us, and so we
 586          * cannot forget this route here.  Let the split-horizon route
 587          * suppress the fragmented routes and then itself be forgotten.
 588          *
 589          * Include the routes for both ends of point-to-point interfaces
 590          * among those suppressed by split-horizon, since the other side
 591          * should knows them as well as we do.
 592          *
 593          * Notice spare routes with the same metric that we are about to
 594          * advertise, to split the horizon on redundant, inactive paths.
 595          */
 596         if (ws.ifp != 0
 597             && !(ws.state & WS_ST_QUERY)
 598             && (ws.state & WS_ST_TO_ON_NET)
 599             && (!(RT->rt_state & RS_IF)
 600                 || ws.ifp->int_if_flags & IFF_POINTOPOINT)) {
 601                 for (rts = RT->rt_spares, i = NUM_SPARES; i != 0; i--, rts++) {
 602                         if (rts->rts_metric > metric
 603                             || rts->rts_ifp != ws.ifp)
 604                                 continue;
 605
 606                         /* If we do not mark the route with AGS_SPLIT_HZ here,
 607                          * it will be poisoned-reverse, or advertised back
 608                          * toward its source with an infinite metric.
 609                          * If we have recently advertised the route with a
 610                          * better metric than we now have, then we should
 611                          * poison-reverse the route before suppressing it for
 612                          * split-horizon.
 613                          *
 614                          * In almost all cases, if there is no spare for the
 615                          * route then it is either old and dead or a brand
 616                          * new route. If it is brand new, there is no need
 617                          * for poison-reverse. If it is old and dead, it
 618                          * is already poisoned.
 619                          */
 620                         if (RT->rt_poison_time < now_expire
 621                             || RT->rt_poison_metric >= metric
 622                             || RT->rt_spares[1].rts_gate == 0) {
 623                                 ags |= AGS_SPLIT_HZ;
 624                                 ags &= ~AGS_SUPPRESS;
 625                         }
 626                         metric = HOPCNT_INFINITY;
 627                         break;
 628                 }
 629         }
 630
 631         /* Keep track of the best metric with which the
 632          * route has been advertised recently.
 633          */
 634         if (RT->rt_poison_metric >= metric
 635             || RT->rt_poison_time < now_expire) {
 636                 RT->rt_poison_time = now.tv_sec;
 637                 RT->rt_poison_metric = metric;
 638         }
 639
 640         /* Adjust the outgoing metric by the cost of the link.
 641          * Avoid aggregation when a route is counting to infinity.
 642          */
 643         pref = RT->rt_poison_metric + ws.metric;
 644         metric += ws.metric;
 645
 646         /* Do not advertise stable routes that will be ignored,
 647          * unless we are answering a query.
 648          * If the route recently was advertised with a metric that
 649          * would have been less than infinity through this interface,
 650          * we need to continue to advertise it in order to poison it.
 651          */
 652         if (metric >= HOPCNT_INFINITY) {
 653                 if (!(ws.state & WS_ST_QUERY)
 654                     && (pref >= HOPCNT_INFINITY
 655                         || RT->rt_poison_time < now_garbage))
 656                         return 0;
 657
 658                 metric = HOPCNT_INFINITY;
 659         }
 660
 661         ag_check(dst, RT->rt_mask, 0, nhop, metric, pref,
 662                  RT->rt_seqno, RT->rt_tag, ags, supply_out);
 663         return 0;
 664 #undef RT
 665 }
 666
 667
 668 /* Supply dst with the contents of the routing tables.
 669  * If this won't fit in one packet, chop it up into several.
 670  */
 671 void
 672 supply(struct sockaddr_in *dst,
 673        struct interface *ifp,           /* output interface */
 674        enum output_type type,
 675        int flash,                       /* 1=flash update */
 676        int vers,                        /* RIP version */
 677        int passwd_ok)                   /* OK to include cleartext password */
 678 {
 679         struct rt_entry *rt;
 680         int def_metric;
 681
 682
 683         ws.state = 0;
 684         ws.gen_limit = 1024;
 685
 686         ws.to = *dst;
 687         ws.to_std_mask = std_mask(ws.to.sin_addr.s_addr);
 688         ws.to_std_net = ntohl(ws.to.sin_addr.s_addr) & ws.to_std_mask;
 689
 690         if (ifp != 0) {
 691                 ws.to_mask = ifp->int_mask;
 692                 ws.to_net = ifp->int_net;
 693                 if (on_net(ws.to.sin_addr.s_addr, ws.to_net, ws.to_mask))
 694                         ws.state |= WS_ST_TO_ON_NET;
 695
 696         } else {
 697                 ws.to_mask = ripv1_mask_net(ws.to.sin_addr.s_addr, 0);
 698                 ws.to_net = ntohl(ws.to.sin_addr.s_addr) & ws.to_mask;
 699                 rt = rtfind(dst->sin_addr.s_addr);
 700                 if (rt)
 701                         ifp = rt->rt_ifp;
 702         }
 703
 704         ws.npackets = 0;
 705         if (flash)
 706                 ws.state |= WS_ST_FLASH;
 707
 708         if ((ws.ifp = ifp) == 0) {
 709                 ws.metric = 1;
 710         } else {
 711                 /* Adjust the advertised metric by the outgoing interface
 712                  * metric.
 713                  */
 714                 ws.metric = ifp->int_metric+1;
 715         }
 716
 717         ripv12_buf.rip.rip_vers = vers;
 718
 719         switch (type) {
 720         case OUT_MULTICAST:
 721                 if (ifp->int_if_flags & IFF_MULTICAST)
 722                         v2buf.type = OUT_MULTICAST;
 723                 else
 724                         v2buf.type = NO_OUT_MULTICAST;
 725                 v12buf.type = OUT_BROADCAST;
 726                 break;
 727
 728         case OUT_QUERY:
 729                 ws.state |= WS_ST_QUERY;
 730                 /* fall through */
 731         case OUT_BROADCAST:
 732         case OUT_UNICAST:
 733                 v2buf.type = (vers == RIPv2) ? type : NO_OUT_RIPV2;
 734                 v12buf.type = type;
 735                 break;
 736
 737         case NO_OUT_MULTICAST:
 738         case NO_OUT_RIPV2:
 739                 break;                  /* no output */
 740         }
 741
 742         if (vers == RIPv2) {
 743                 /* full RIPv2 only if cannot be heard by RIPv1 listeners */
 744                 if (type != OUT_BROADCAST)
 745                         ws.state |= WS_ST_RIP2_ALL;
 746                 if ((ws.state & WS_ST_QUERY)
 747                     || !(ws.state & WS_ST_TO_ON_NET)) {
 748                         ws.state |= (WS_ST_AG | WS_ST_SUPER_AG);
 749                 } else if (ifp == 0 || !(ifp->int_state & IS_NO_AG)) {
 750                         ws.state |= WS_ST_AG;
 751                         if (type != OUT_BROADCAST
 752                             && (ifp == 0
 753                                 || !(ifp->int_state & IS_NO_SUPER_AG)))
 754                                 ws.state |= WS_ST_SUPER_AG;
 755                 }
 756         }
 757
 758         ws.a = (vers == RIPv2) ? find_auth(ifp) : 0;
 759         if (!passwd_ok && ws.a != 0 && ws.a->type == RIP_AUTH_PW)
 760                 ws.a = 0;
 761         clr_ws_buf(&v12buf,ws.a);
 762         clr_ws_buf(&v2buf,ws.a);
 763
 764         /*  Fake a default route if asked and if there is not already
 765          * a better, real default route.
 766          */
 767         if (supplier && (def_metric = ifp->int_d_metric) != 0) {
 768                 if (0 == (rt = rtget(RIP_DEFAULT, 0))
 769                     || rt->rt_metric+ws.metric >= def_metric) {
 770                         ws.state |= WS_ST_DEFAULT;
 771                         ag_check(0, 0, 0, 0, def_metric, def_metric,
 772                                  0, 0, 0, supply_out);
 773                 } else {
 774                         def_metric = rt->rt_metric+ws.metric;
 775                 }
 776
 777                 /* If both RIPv2 and the poor-man's router discovery
 778                  * kludge are on, arrange to advertise an extra
 779                  * default route via RIPv1.
 780                  */
 781                 if ((ws.state & WS_ST_RIP2_ALL)
 782                     && (ifp->int_state & IS_PM_RDISC)) {
 783                         ripv12_buf.rip.rip_vers = RIPv1;
 784                         v12buf.n->n_family = RIP_AF_INET;
 785                         v12buf.n->n_dst = htonl(RIP_DEFAULT);
 786                         v12buf.n->n_metric = htonl(def_metric);
 787                         v12buf.n++;
 788                 }
 789         }
 790
 791         rn_walktree(rhead, walk_supply, 0);
 792         ag_flush(0,0,supply_out);
 793
 794         /* Flush the packet buffers, provided they are not empty and
 795          * do not contain only the password.
 796          */
 797         if (v12buf.n != v12buf.base
 798             && (v12buf.n > v12buf.base+1
 799                 || v12buf.base->n_family != RIP_AF_AUTH))
 800                 supply_write(&v12buf);
 801         if (v2buf.n != v2buf.base
 802             && (v2buf.n > v2buf.base+1
 803                 || v2buf.base->n_family != RIP_AF_AUTH))
 804                 supply_write(&v2buf);
 805
 806         /* If we sent nothing and this is an answer to a query, send
 807          * an empty buffer.
 808          */
 809         if (ws.npackets == 0
 810             && (ws.state & WS_ST_QUERY))
 811                 supply_write(&v12buf);
 812 }
 813
 814
 815 /* send all of the routing table or just do a flash update
 816  */
 817 void
 818 rip_bcast(int flash)
 819 {
 820 #ifdef _HAVE_SIN_LEN
 821         static struct sockaddr_in dst = {sizeof(dst), AF_INET, 0, {0}, {0}};
 822 #else
 823         static struct sockaddr_in dst = {AF_INET};
 824 #endif
 825         struct interface *ifp;
 826         enum output_type type;
 827         int vers;
 828         struct timeval rtime;
 829
 830
 831         need_flash = 0;
 832         intvl_random(&rtime, MIN_WAITTIME, MAX_WAITTIME);
 833         no_flash = rtime;
 834         timevaladd(&no_flash, &now);
 835
 836         if (rip_sock < 0)
 837                 return;
 838
 839         trace_act("send %s and inhibit dynamic updates for %.3f sec",
 840                   flash ? "dynamic update" : "all routes",
 841                   rtime.tv_sec + ((float)rtime.tv_usec)/1000000.0);
 842
 843         for (ifp = ifnet; ifp != 0; ifp = ifp->int_next) {
 844                 /* Skip interfaces not doing RIP.
 845                  * Do try broken interfaces to see if they have healed.
 846                  */
 847                 if (IS_RIP_OUT_OFF(ifp->int_state))
 848                         continue;
 849
 850                 /* skip turned off interfaces */
 851                 if (!iff_up(ifp->int_if_flags))
 852                         continue;
 853
 854                 vers = (ifp->int_state & IS_NO_RIPV1_OUT) ? RIPv2 : RIPv1;
 855
 856                 if (ifp->int_if_flags & IFF_BROADCAST) {
 857                         /* ordinary, hardware interface */
 858                         dst.sin_addr.s_addr = ifp->int_brdaddr;
 859
 860                         if (vers == RIPv2
 861                             && !(ifp->int_state  & IS_NO_RIP_MCAST)) {
 862                                 type = OUT_MULTICAST;
 863                         } else {
 864                                 type = OUT_BROADCAST;
 865                         }
 866
 867                 } else if (ifp->int_if_flags & IFF_POINTOPOINT) {
 868                         /* point-to-point hardware interface */
 869                         dst.sin_addr.s_addr = ifp->int_dstaddr;
 870                         type = OUT_UNICAST;
 871
 872                 } else if (ifp->int_state & IS_REMOTE) {
 873                         /* remote interface */
 874                         dst.sin_addr.s_addr = ifp->int_addr;
 875                         type = OUT_UNICAST;
 876
 877                 } else {
 878                         /* ATM, HIPPI, etc. */
 879                         continue;
 880                 }
 881
 882                 supply(&dst, ifp, type, flash, vers, 1);
 883         }
 884
 885         update_seqno++;                 /* all routes are up to date */
 886 }
 887
 888
 889 /* Ask for routes
 890  * Do it only once to an interface, and not even after the interface
 891  * was broken and recovered.
 892  */
 893 void
 894 rip_query(void)
 895 {
 896 #ifdef _HAVE_SIN_LEN
 897         static struct sockaddr_in dst = {sizeof(dst), AF_INET, 0, {0}, {0}};
 898 #else
 899         static struct sockaddr_in dst = {AF_INET};
 900 #endif
 901         struct interface *ifp;
 902         struct rip buf;
 903         enum output_type type;
 904
 905
 906         if (rip_sock < 0)
 907                 return;
 908
 909         memset(&buf, 0, sizeof(buf));
 910
 911         for (ifp = ifnet; ifp; ifp = ifp->int_next) {
 912                 /* Skip interfaces those already queried.
 913                  * Do not ask via interfaces through which we don't
 914                  * accept input.  Do not ask via interfaces that cannot
 915                  * send RIP packets.
 916                  * Do try broken interfaces to see if they have healed.
 917                  */
 918                 if (IS_RIP_IN_OFF(ifp->int_state)
 919                     || ifp->int_query_time != NEVER)
 920                         continue;
 921
 922                 /* skip turned off interfaces */
 923                 if (!iff_up(ifp->int_if_flags))
 924                         continue;
 925
 926                 buf.rip_vers = (ifp->int_state&IS_NO_RIPV1_OUT) ? RIPv2:RIPv1;
 927                 buf.rip_cmd = RIPCMD_REQUEST;
 928                 buf.rip_nets[0].n_family = RIP_AF_UNSPEC;
 929                 buf.rip_nets[0].n_metric = htonl(HOPCNT_INFINITY);
 930
 931                 /* Send a RIPv1 query only if allowed and if we will
 932                  * listen to RIPv1 routers.
 933                  */
 934                 if ((ifp->int_state & IS_NO_RIPV1_OUT)
 935                     || (ifp->int_state & IS_NO_RIPV1_IN)) {
 936                         buf.rip_vers = RIPv2;
 937                 } else {
 938                         buf.rip_vers = RIPv1;
 939                 }
 940
 941                 if (ifp->int_if_flags & IFF_BROADCAST) {
 942                         /* ordinary, hardware interface */
 943                         dst.sin_addr.s_addr = ifp->int_brdaddr;
 944
 945                         /* Broadcast RIPv1 queries and RIPv2 queries
 946                          * when the hardware cannot multicast.
 947                          */
 948                         if (buf.rip_vers == RIPv2
 949                             && (ifp->int_if_flags & IFF_MULTICAST)
 950                             && !(ifp->int_state  & IS_NO_RIP_MCAST)) {
 951                                 type = OUT_MULTICAST;
 952                         } else {
 953                                 type = OUT_BROADCAST;
 954                         }
 955
 956                 } else if (ifp->int_if_flags & IFF_POINTOPOINT) {
 957                         /* point-to-point hardware interface */
 958                         dst.sin_addr.s_addr = ifp->int_dstaddr;
 959                         type = OUT_UNICAST;
 960
 961                 } else if (ifp->int_state & IS_REMOTE) {
 962                         /* remote interface */
 963                         dst.sin_addr.s_addr = ifp->int_addr;
 964                         type = OUT_UNICAST;
 965
 966                 } else {
 967                         /* ATM, HIPPI, etc. */
 968                         continue;
 969                 }
 970
 971                 ifp->int_query_time = now.tv_sec+SUPPLY_INTERVAL;
 972                 if (output(type, &dst, ifp, &buf, sizeof(buf)) < 0)
 973                         if_sick(ifp);
 974         }
 975 }