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
51struct ospf_route *
52ospf_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
73void
74ospf_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
129void
130ospf_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
197struct ia_args
198{
199  struct route_table *rt;
200  struct route_table *rtrs;
201  struct ospf_area *area;
202};
203
204int
205process_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
290void
291ospf_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
300int
301ospf_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
307void
308ospf_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
439void
440ospf_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
539int
540process_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
597void
598ospf_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
610void
611ospf_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}
727