ospfd/ospf_ia.c

   1 /*
   2  * OSPF inter-area routing.
   3  * Copyright (C) 1999, 2000 Alex Zinin, Toshiaki Takada
   4  *
   5  * This file is part of GNU Zebra.
   6  *
   7  * GNU Zebra is free software; you can redistribute it and/or modify it
   8  * under the terms of the GNU General Public License as published by the
   9  * Free Software Foundation; either version 2, or (at your option) any
  10  * later version.
  11  *
  12  * GNU Zebra is distributed in the hope that it will be useful, but
  13  * WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with GNU Zebra; see the file COPYING.  If not, write to the Free
  19  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  20  * 02111-1307, USA.
  21  */
  22
  23
  24 #include <zebra.h>
  25
  26 #include "thread.h"
  27 #include "memory.h"
  28 #include "hash.h"
  29 #include "linklist.h"
  30 #include "prefix.h"
  31 #include "table.h"
  32 #include "log.h"
  33
  34 #include "ospfd/ospfd.h"
  35 #include "ospfd/ospf_interface.h"
  36 #include "ospfd/ospf_ism.h"
  37 #include "ospfd/ospf_asbr.h"
  38 #include "ospfd/ospf_lsa.h"
  39 #include "ospfd/ospf_lsdb.h"
  40 #include "ospfd/ospf_neighbor.h"
  41 #include "ospfd/ospf_nsm.h"
  42 #include "ospfd/ospf_spf.h"
  43 #include "ospfd/ospf_route.h"
  44 #include "ospfd/ospf_ase.h"
  45 #include "ospfd/ospf_abr.h"
  46 #include "ospfd/ospf_ia.h"
  47 #include "ospfd/ospf_dump.h"
  48
  49 #define DEBUG
  50
  51 struct ospf_route *
  52 ospf_find_abr_route (struct route_table *rtrs,
  53                      struct prefix_ipv4 *abr,
  54                      struct ospf_area *area)
  55 {
  56   struct route_node *rn;
  57   struct ospf_route *or;
  58   listnode node;
  59
  60   if ((rn = route_node_lookup (rtrs, (struct prefix *) abr)) == NULL)
  61     return NULL;
  62
  63   route_unlock_node (rn);
  64
  65   for (node = listhead ((list) rn->info); node; nextnode (node))
  66     if ((or = getdata (node)) != NULL)
  67       if (IPV4_ADDR_SAME (&or->u.std.area_id, &area->area_id) && (or->u.std.flags & ROUTER_LSA_BORDER))
  68         return or;
  69
  70   return NULL;
  71 }
  72
  73 void
  74 ospf_ia_network_route (struct route_table *rt, struct prefix_ipv4 *p,
  75                        struct ospf_route *new_or, struct ospf_route *abr_or)
  76 {
  77   struct route_node *rn1;
  78   struct ospf_route *or;
  79
  80   if (IS_DEBUG_OSPF_EVENT)
  81     zlog_info ("ospf_ia_network_route(): processing summary route to %s/%d",
  82                inet_ntoa (p->prefix), p->prefixlen);
  83
  84   /* Find a route to the same dest */
  85   if ((rn1 = route_node_lookup (rt, (struct prefix *) p)))
  86     {
  87       int res;
  88
  89       route_unlock_node (rn1);
  90
  91       if ((or = rn1->info))
  92         {
  93           if (IS_DEBUG_OSPF_EVENT)
  94             zlog_info ("ospf_ia_network_route(): "
  95                        "Found a route to the same network");
  96           /* Check the existing route. */
  97           if ((res = ospf_route_cmp (new_or, or)) < 0)
  98             {
  99               /* New route is better, so replace old one. */
 100               ospf_route_subst (rn1, new_or, abr_or);
 101             }
 102           else if (res == 0)
 103             {
 104               /* New and old route are equal, so next hops can be added. */
 105               route_lock_node (rn1);
 106               ospf_route_copy_nexthops (or, abr_or->path);
 107               route_unlock_node (rn1);
 108
 109               /* new route can be deleted, because existing route has been updated. */
 110               ospf_route_free (new_or);
 111             }
 112           else
 113             {
 114               /* New route is worse, so free it. */
 115               ospf_route_free (new_or);
 116               return;
 117             }
 118         } /* if (or)*/
 119     } /*if (rn1)*/
 120   else
 121     { /* no route */
 122       if (IS_DEBUG_OSPF_EVENT)
 123         zlog_info ("ospf_ia_network_route(): add new route to %s/%d",
 124                    inet_ntoa (p->prefix), p->prefixlen);
 125       ospf_route_add (rt, p, new_or, abr_or);
 126     }
 127 }
 128
 129 void
 130 ospf_ia_router_route (struct route_table *rt, struct prefix_ipv4 *p,
 131                       struct ospf_route *new_or, struct ospf_route *abr_or)
 132 {
 133   struct route_node *rn;
 134   struct ospf_route *or = NULL;
 135   int ret;
 136
 137   if (IS_DEBUG_OSPF_EVENT)
 138     zlog_info ("ospf_ia_router_route(): considering %s/%d",
 139                inet_ntoa (p->prefix), p->prefixlen);
 140   /* Find a route to the same dest */
 141   rn = route_node_get (rt,(struct prefix *) p);
 142
 143   if (rn->info == NULL)
 144     /* This is a new route */
 145     rn->info = list_new ();
 146   else
 147     {
 148       struct ospf_area *or_area;
 149       or_area = ospf_area_lookup_by_area_id (new_or->u.std.area_id);
 150       assert (or_area);
 151       /* This is an additional route */
 152       route_unlock_node (rn);
 153       or = ospf_find_asbr_route_through_area (rt, p, or_area);
 154     }
 155
 156   if (or)
 157     {
 158       if (IS_DEBUG_OSPF_EVENT)
 159         zlog_info ("ospf_ia_router_route(): "
 160                    "a route to the same ABR through the same area exists");
 161       /* New route is better */
 162       if ((ret = ospf_route_cmp (new_or, or)) < 0)
 163         {
 164           listnode_delete (rn->info, or);
 165           ospf_route_free (or);
 166           /* proceed down */
 167         }
 168       /* Routes are the same */
 169       else if (ret == 0)
 170         {
 171           if (IS_DEBUG_OSPF_EVENT)
 172             zlog_info ("ospf_ia_router_route(): merging the new route");
 173
 174           ospf_route_copy_nexthops (or, abr_or->path);
 175           ospf_route_free (new_or);
 176           return;
 177         }
 178       /* New route is worse */
 179       else
 180         {
 181           if (IS_DEBUG_OSPF_EVENT)
 182             zlog_info ("ospf_ia_router_route(): skipping the new route");
 183           ospf_route_free (new_or);
 184           return;
 185         }
 186     }
 187
 188   ospf_route_copy_nexthops (new_or, abr_or->path);
 189
 190   if (IS_DEBUG_OSPF_EVENT)
 191     zlog_info ("ospf_ia_router_route(): adding the new route");
 192
 193   listnode_add (rn->info, new_or);
 194 }
 195
 196 \f
 197 struct ia_args
 198 {
 199   struct route_table *rt;
 200   struct route_table *rtrs;
 201   struct ospf_area *area;
 202 };
 203
 204 int
 205 process_summary_lsa (struct ospf_lsa *l, void *v, int i)
 206 {
 207   struct ospf_area_range *range;
 208   struct ospf_route *abr_or, *new_or;
 209   struct summary_lsa *sl;
 210   struct prefix_ipv4 p, abr;
 211   u_int32_t metric;
 212   struct ia_args *args;
 213
 214   if (l == NULL)
 215     return 0;
 216
 217   args = (struct ia_args *) v;
 218   sl = (struct summary_lsa *) l->data;
 219
 220   if (IS_DEBUG_OSPF_EVENT)
 221     zlog_info ("process_summary_lsa(): LS ID: %s", inet_ntoa (sl->header.id));
 222
 223   metric = GET_METRIC (sl->metric);
 224
 225   if (metric == OSPF_LS_INFINITY)
 226     return 0;
 227
 228   if (IS_LSA_MAXAGE (l))
 229     return 0;
 230
 231   if (ospf_lsa_is_self_originated (l))
 232     return 0;
 233
 234   p.family = AF_INET;
 235   p.prefix = sl->header.id;
 236
 237   if (sl->header.type == OSPF_SUMMARY_LSA)
 238     p.prefixlen = ip_masklen (sl->mask);
 239   else
 240     p.prefixlen = IPV4_MAX_BITLEN;
 241
 242   apply_mask_ipv4 (&p);
 243
 244   if (sl->header.type == OSPF_SUMMARY_LSA &&
 245       (range = ospf_area_range_match_any (ospf_top, &p)) &&
 246       ospf_area_range_active (range))
 247     return 0;
 248
 249   if (ospf_top->abr_type != OSPF_ABR_STAND &&
 250       args->area->external_routing != OSPF_AREA_DEFAULT &&
 251       p.prefix.s_addr == OSPF_DEFAULT_DESTINATION &&
 252       p.prefixlen == 0)
 253     return 0; /* Ignore summary default from a stub area */
 254
 255   abr.family = AF_INET;
 256   abr.prefix = sl->header.adv_router;
 257   abr.prefixlen = IPV4_MAX_BITLEN;
 258   apply_mask_ipv4 (&abr);
 259
 260   abr_or = ospf_find_abr_route (args->rtrs, &abr, args->area);
 261
 262   if (abr_or == NULL)
 263     return 0;
 264
 265   new_or = ospf_route_new ();
 266   new_or->type = OSPF_DESTINATION_NETWORK;
 267   new_or->id = sl->header.id;
 268   new_or->mask = sl->mask;
 269   new_or->u.std.options = sl->header.options;
 270   new_or->u.std.origin = (struct lsa_header *) sl;
 271   new_or->cost = abr_or->cost + metric;
 272   new_or->u.std.area_id = args->area->area_id;
 273 #ifdef HAVE_NSSA
 274   new_or->u.std.external_routing = args->area->external_routing;
 275 #endif /* HAVE_NSSA */
 276   new_or->path_type = OSPF_PATH_INTER_AREA;
 277
 278   if (sl->header.type == OSPF_SUMMARY_LSA)
 279     ospf_ia_network_route (args->rt, &p, new_or, abr_or);
 280   else
 281     {
 282       new_or->type = OSPF_DESTINATION_ROUTER;
 283       new_or->u.std.flags = ROUTER_LSA_EXTERNAL;
 284       ospf_ia_router_route (args->rtrs, &p, new_or, abr_or);
 285     }
 286
 287   return 0;
 288 }
 289
 290 void
 291 ospf_examine_summaries (struct ospf_area * area,
 292                         struct route_table *lsdb_rt,
 293                         struct route_table *rt,
 294                         struct route_table *rtrs)
 295 {
 296   struct ia_args args = {rt, rtrs, area};
 297   foreach_lsa (lsdb_rt, &args, 0, process_summary_lsa);
 298 }
 299
 300 int
 301 ospf_area_is_transit (struct ospf_area *area)
 302 {
 303   return (area->transit == OSPF_TRANSIT_TRUE) ||
 304     ospf_full_virtual_nbrs(area); /* Cisco forgets to set the V-bit :( */
 305 }
 306
 307 void
 308 ospf_update_network_route (struct route_table *rt,
 309                            struct route_table *rtrs,
 310                            struct summary_lsa *lsa,
 311                            struct prefix_ipv4 *p,
 312                            struct ospf_area *area)
 313 {
 314   struct route_node *rn;
 315   struct ospf_route *or, *abr_or, *new_or;
 316   struct prefix_ipv4 abr;
 317   u_int32_t cost;
 318
 319   abr.family = AF_INET;
 320   abr.prefix =lsa->header.adv_router;
 321   abr.prefixlen = IPV4_MAX_BITLEN;
 322   apply_mask_ipv4 (&abr);
 323
 324   abr_or = ospf_find_abr_route (rtrs, &abr, area);
 325
 326   if (abr_or == NULL)
 327     {
 328       if (IS_DEBUG_OSPF_EVENT)
 329         zlog_info ("ospf_update_network_route(): can't find a route to the ABR");
 330       return;
 331     }
 332
 333   cost = abr_or->cost + GET_METRIC (lsa->metric);
 334
 335   rn = route_node_lookup (rt, (struct prefix *) p);
 336
 337   if (! rn)
 338     {
 339       if (ospf_top->abr_type != OSPF_ABR_SHORTCUT)
 340         return; /* Standard ABR can update only already installed
 341                    backbone paths                                       */
 342       if (IS_DEBUG_OSPF_EVENT)
 343         zlog_info ("ospf_update_network_route(): "
 344                    "Allowing Shortcut ABR to add new route");
 345       new_or = ospf_route_new ();
 346       new_or->type = OSPF_DESTINATION_NETWORK;
 347       new_or->id = lsa->header.id;
 348       new_or->mask = lsa->mask;
 349       new_or->u.std.options = lsa->header.options;
 350       new_or->u.std.origin = (struct lsa_header *) lsa;
 351       new_or->cost = cost;
 352       new_or->u.std.area_id = area->area_id;
 353 #ifdef HAVE_NSSA
 354       new_or->u.std.external_routing = area->external_routing;
 355 #endif /* HAVE_NSSA */
 356       new_or->path_type = OSPF_PATH_INTER_AREA;
 357       ospf_route_add (rt, p, new_or, abr_or);
 358
 359       return;
 360     }
 361   else
 362     {
 363       route_unlock_node (rn);
 364       if (rn->info == NULL)
 365         return;
 366     }
 367
 368   or = rn->info;
 369
 370   if (or->path_type != OSPF_PATH_INTRA_AREA &&
 371       or->path_type != OSPF_PATH_INTER_AREA)
 372     {
 373       if (IS_DEBUG_OSPF_EVENT)
 374         zlog_info ("ospf_update_network_route(): ERR: path type is wrong");
 375       return;
 376     }
 377
 378   if (ospf_top->abr_type == OSPF_ABR_SHORTCUT)
 379     {
 380       if (or->path_type == OSPF_PATH_INTRA_AREA &&
 381           !OSPF_IS_AREA_ID_BACKBONE (or->u.std.area_id))
 382         {
 383           if (IS_DEBUG_OSPF_EVENT)
 384             zlog_info ("ospf_update_network_route(): Shortcut: "
 385                        "this intra-area path is not backbone");
 386           return;
 387         }
 388     }
 389   else   /* Not Shortcut ABR */
 390     {
 391       if (!OSPF_IS_AREA_ID_BACKBONE (or->u.std.area_id))
 392         {
 393           if (IS_DEBUG_OSPF_EVENT)
 394             zlog_info ("ospf_update_network_route(): "
 395                        "route is not BB-associated");
 396           return; /* We can update only BB routes */
 397         }
 398     }
 399
 400   if (or->cost < cost)
 401     {
 402       if (IS_DEBUG_OSPF_EVENT)
 403         zlog_info ("ospf_update_network_route(): new route is worse");
 404       return;
 405     }
 406
 407   if (or->cost == cost)
 408     {
 409       if (IS_DEBUG_OSPF_EVENT)
 410         zlog_info ("ospf_update_network_route(): "
 411                    "new route is same distance, adding nexthops");
 412       ospf_route_copy_nexthops (or, abr_or->path);
 413     }
 414
 415   if (or->cost > cost)
 416     {
 417       if (IS_DEBUG_OSPF_EVENT)
 418         zlog_info ("ospf_update_network_route(): "
 419                    "new route is better, overriding nexthops");
 420       ospf_route_subst_nexthops (or, abr_or->path);
 421       or->cost = cost;
 422
 423       if ((ospf_top->abr_type == OSPF_ABR_SHORTCUT) &&
 424           !OSPF_IS_AREA_ID_BACKBONE (or->u.std.area_id))
 425         {
 426           or->path_type = OSPF_PATH_INTER_AREA;
 427           or->u.std.area_id = area->area_id;
 428 #ifdef HAVE_NSSA
 429           or->u.std.external_routing = area->external_routing;
 430 #endif /* HAVE_NSSA */
 431           /* Note that we can do this only in Shortcut ABR mode,
 432              because standard ABR must leave the route type and area
 433              unchanged
 434           */
 435         }
 436     }
 437 }
 438
 439 void
 440 ospf_update_router_route (struct route_table *rtrs,
 441                           struct summary_lsa *lsa,
 442                           struct prefix_ipv4 *p,
 443                           struct ospf_area *area)
 444 {
 445   struct ospf_route *or, *abr_or, *new_or;
 446   struct prefix_ipv4 abr;
 447   u_int32_t cost;
 448
 449   abr.family = AF_INET;
 450   abr.prefix = lsa->header.adv_router;
 451   abr.prefixlen = IPV4_MAX_BITLEN;
 452   apply_mask_ipv4 (&abr);
 453
 454   abr_or = ospf_find_abr_route (rtrs, &abr, area);
 455
 456   if (abr_or == NULL)
 457     {
 458       if (IS_DEBUG_OSPF_EVENT)
 459         zlog_info ("ospf_update_router_route(): can't find a route to the ABR");
 460       return;
 461     }
 462
 463   cost = abr_or->cost + GET_METRIC (lsa->metric);
 464
 465   /* First try to find a backbone path,
 466      because standard ABR can update only BB-associated paths */
 467
 468   if ((ospf_top->backbone == NULL) &&
 469       (ospf_top->abr_type != OSPF_ABR_SHORTCUT))
 470
 471      /* no BB area, not Shortcut ABR, exiting */
 472      return;
 473
 474   or = ospf_find_asbr_route_through_area (rtrs, p, ospf_top->backbone);
 475
 476   if (or == NULL)
 477     {
 478       if (ospf_top->abr_type != OSPF_ABR_SHORTCUT)
 479
 480          /* route to ASBR through the BB not found
 481             the router is not Shortcut ABR, exiting */
 482
 483           return;
 484       else
 485         /* We're a Shortcut ABR*/
 486         {
 487           /* Let it either add a new router or update the route
 488              through the same (non-BB) area. */
 489
 490           new_or = ospf_route_new ();
 491           new_or->type = OSPF_DESTINATION_ROUTER;
 492           new_or->id = lsa->header.id;
 493           new_or->mask = lsa->mask;
 494           new_or->u.std.options = lsa->header.options;
 495           new_or->u.std.origin = (struct lsa_header *)lsa;
 496           new_or->cost = cost;
 497           new_or->u.std.area_id = area->area_id;
 498 #ifdef HAVE_NSSA
 499           new_or->u.std.external_routing = area->external_routing;
 500 #endif /* HAVE_NSSA */
 501           new_or->path_type = OSPF_PATH_INTER_AREA;
 502           new_or->u.std.flags = ROUTER_LSA_EXTERNAL;
 503           ospf_ia_router_route (rtrs, p, new_or, abr_or);
 504
 505           return;
 506         }
 507     }
 508
 509   /* At this point the "or" is always bb-associated */
 510
 511   if (!(or->u.std.flags & ROUTER_LSA_EXTERNAL))
 512     {
 513       if (IS_DEBUG_OSPF_EVENT)
 514         zlog_info ("ospf_upd_router_route(): the remote router is not an ASBR");
 515       return;
 516     }
 517
 518   if (or->path_type != OSPF_PATH_INTRA_AREA &&
 519       or->path_type != OSPF_PATH_INTER_AREA)
 520     return;
 521
 522   if (or->cost < cost)
 523     return;
 524
 525   else if (or->cost == cost)
 526     ospf_route_copy_nexthops (or, abr_or->path);
 527
 528   else if (or->cost > cost)
 529     {
 530       ospf_route_subst_nexthops (or, abr_or->path);
 531       or->cost = cost;
 532
 533       /* Even if the ABR runs in Shortcut mode, we can't change
 534          the path type and area, because the "or" is always bb-associated
 535          at this point and even Shortcut ABR can't change these attributes */
 536     }
 537 }
 538
 539 int
 540 process_transit_summary_lsa (struct ospf_lsa *l, void *v, int i)
 541 {
 542   struct summary_lsa *sl;
 543   struct prefix_ipv4 p;
 544   u_int32_t metric;
 545   struct ia_args *args;
 546
 547   if (l == NULL)
 548     return 0;
 549
 550   args = (struct ia_args *) v;
 551   sl = (struct summary_lsa *) l->data;
 552
 553   if (IS_DEBUG_OSPF_EVENT)
 554     zlog_info ("process_transit_summaries(): LS ID: %s",
 555                inet_ntoa (l->data->id));
 556   metric = GET_METRIC (sl->metric);
 557
 558   if (metric == OSPF_LS_INFINITY)
 559     {
 560       if (IS_DEBUG_OSPF_EVENT)
 561         zlog_info ("process_transit_summaries(): metric is infinity, skip");
 562       return 0;
 563     }
 564
 565   if (IS_LSA_MAXAGE (l))
 566     {
 567       if (IS_DEBUG_OSPF_EVENT)
 568         zlog_info ("process_transit_summaries(): This LSA is too old");
 569       return 0;
 570     }
 571
 572   if (ospf_lsa_is_self_originated (l))
 573     {
 574       if (IS_DEBUG_OSPF_EVENT)
 575         zlog_info ("process_transit_summaries(): This LSA is mine, skip");
 576       return 0;
 577     }
 578
 579   p.family = AF_INET;
 580   p.prefix = sl->header.id;
 581
 582   if (sl->header.type == OSPF_SUMMARY_LSA)
 583     p.prefixlen = ip_masklen (sl->mask);
 584   else
 585     p.prefixlen = IPV4_MAX_BITLEN;
 586
 587   apply_mask_ipv4 (&p);
 588
 589   if (sl->header.type == OSPF_SUMMARY_LSA)
 590     ospf_update_network_route (args->rt, args->rtrs, sl, &p, args->area);
 591   else
 592     ospf_update_router_route (args->rtrs, sl, &p, args->area);
 593
 594   return 0;
 595 }
 596
 597 void
 598 ospf_examine_transit_summaries (struct ospf_area *area,
 599                                 /* struct ospf_lsdb *lsdb, */
 600                                 struct route_table *lsdb_rt,
 601                                 struct route_table *rt,
 602                                 struct route_table *rtrs)
 603 {
 604   struct ia_args args = {rt, rtrs, area};
 605
 606   /* ospf_lsdb_iterator (lsdb, &args, 0, process_transit_summary_lsa); */
 607   foreach_lsa (lsdb_rt, &args, 0, process_transit_summary_lsa);
 608 }
 609
 610 void
 611 ospf_ia_routing (struct route_table *rt,
 612                  struct route_table *rtrs)
 613 {
 614   struct ospf_area * area;
 615
 616   if (IS_DEBUG_OSPF_EVENT)
 617     zlog_info ("ospf_ia_routing():start");
 618
 619   if (OSPF_IS_ABR)
 620     {
 621       listnode node;
 622       struct ospf_area *area;
 623
 624       switch (ospf_top->abr_type)
 625         {
 626         case OSPF_ABR_STAND:
 627           if (IS_DEBUG_OSPF_EVENT)
 628             zlog_info ("ospf_ia_routing():Standard ABR");
 629
 630           if ((area = ospf_top->backbone))
 631             {
 632               listnode node;
 633
 634               if (IS_DEBUG_OSPF_EVENT)
 635                 {
 636                   zlog_info ("ospf_ia_routing():backbone area found");
 637                   zlog_info ("ospf_ia_routing():examining summaries");
 638                 }
 639
 640               OSPF_EXAMINE_SUMMARIES_ALL (area, rt, rtrs);
 641
 642               for (node = listhead (ospf_top->areas); node; nextnode (node))
 643                 if ((area = getdata (node)) != NULL)
 644                   if (area != ospf_top->backbone)
 645                     if (ospf_area_is_transit (area))
 646                       OSPF_EXAMINE_TRANSIT_SUMMARIES_ALL (area, rt, rtrs);
 647             }
 648           else
 649             if (IS_DEBUG_OSPF_EVENT)
 650               zlog_info ("ospf_ia_routing():backbone area NOT found");
 651           break;
 652         case OSPF_ABR_IBM:
 653         case OSPF_ABR_CISCO:
 654           if (IS_DEBUG_OSPF_EVENT)
 655             zlog_info ("ospf_ia_routing():Alternative Cisco/IBM ABR");
 656           area = ospf_top->backbone; /* Find the BB */
 657
 658           /* If we have an active BB connection */
 659           if (area && ospf_act_bb_connection ())
 660             {
 661               if (IS_DEBUG_OSPF_EVENT)
 662                 {
 663                   zlog_info ("ospf_ia_routing(): backbone area found");
 664                   zlog_info ("ospf_ia_routing(): examining BB summaries");
 665                 }
 666
 667               OSPF_EXAMINE_SUMMARIES_ALL (area, rt, rtrs);
 668
 669               for (node = listhead (ospf_top->areas); node; nextnode (node))
 670                 if ((area = getdata (node)) != NULL)
 671                   if (area != ospf_top->backbone)
 672                     if (ospf_area_is_transit (area))
 673                       OSPF_EXAMINE_TRANSIT_SUMMARIES_ALL (area, rt, rtrs);
 674             }
 675           else
 676             { /* No active BB connection--consider all areas */
 677               if (IS_DEBUG_OSPF_EVENT)
 678                 zlog_info ("ospf_ia_routing(): "
 679                            "Active BB connection not found");
 680               for (node = listhead (ospf_top->areas); node; nextnode (node))
 681                 if ((area = getdata (node)) != NULL)
 682                   OSPF_EXAMINE_SUMMARIES_ALL (area, rt, rtrs);
 683             }
 684           break;
 685         case OSPF_ABR_SHORTCUT:
 686           if (IS_DEBUG_OSPF_EVENT)
 687             zlog_info ("ospf_ia_routing():Alternative Shortcut");
 688           area = ospf_top->backbone; /* Find the BB */
 689
 690           /* If we have an active BB connection */
 691           if (area && ospf_act_bb_connection ())
 692             {
 693               if (IS_DEBUG_OSPF_EVENT)
 694                 {
 695                   zlog_info ("ospf_ia_routing(): backbone area found");
 696                   zlog_info ("ospf_ia_routing(): examining BB summaries");
 697                 }
 698               OSPF_EXAMINE_SUMMARIES_ALL (area, rt, rtrs);
 699             }
 700
 701           for (node = listhead (ospf_top->areas); node; nextnode (node))
 702             if ((area = getdata (node)) != NULL)
 703               if (area != ospf_top->backbone)
 704                 if (ospf_area_is_transit (area) ||
 705                     ((area->shortcut_configured != OSPF_SHORTCUT_DISABLE) &&
 706                      ((ospf_top->backbone == NULL) ||
 707                       ((area->shortcut_configured == OSPF_SHORTCUT_ENABLE) &&
 708                        area->shortcut_capability))))
 709                   OSPF_EXAMINE_TRANSIT_SUMMARIES_ALL (area, rt, rtrs);
 710           break;
 711         default:
 712           break;
 713         }
 714     }
 715   else
 716     {
 717       listnode node;
 718
 719       if (IS_DEBUG_OSPF_EVENT)
 720         zlog_info ("ospf_ia_routing():not ABR, considering all areas");
 721
 722       for (node = listhead (ospf_top->areas); node; nextnode (node))
 723         if ((area = getdata (node)) != NULL)
 724           OSPF_EXAMINE_SUMMARIES_ALL (area, rt, rtrs);
 725     }
 726 }