ospfd/ospf_ia.c - quagga - Gitiles

 /*
  * OSPF inter-area routing.
  * Copyright (C) 1999, 2000 Alex Zinin, Toshiaki Takada
  *
  * This file is part of GNU Zebra.
  *
  * GNU Zebra is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License as published by the
  * Free Software Foundation; either version 2, or (at your option) any
  * later version.
  *
  * GNU Zebra is distributed in the hope that it will be useful, but
  * WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with GNU Zebra; see the file COPYING.  If not, write to the Free
  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  * 02111-1307, USA.
  */


 #include <zebra.h>

 #include "thread.h"
 #include "memory.h"
 #include "hash.h"
 #include "linklist.h"
 #include "prefix.h"
 #include "table.h"
 #include "log.h"

 #include "ospfd/ospfd.h"
 #include "ospfd/ospf_interface.h"
 #include "ospfd/ospf_ism.h"
 #include "ospfd/ospf_asbr.h"
 #include "ospfd/ospf_lsa.h"
 #include "ospfd/ospf_lsdb.h"
 #include "ospfd/ospf_neighbor.h"
 #include "ospfd/ospf_nsm.h"
 #include "ospfd/ospf_spf.h"
 #include "ospfd/ospf_route.h"
 #include "ospfd/ospf_ase.h"
 #include "ospfd/ospf_abr.h"
 #include "ospfd/ospf_ia.h"
 #include "ospfd/ospf_dump.h"

 #define DEBUG

 static struct ospf_route *
 ospf_find_abr_route (struct route_table *rtrs,
                      struct prefix_ipv4 *abr,
                      struct ospf_area *area)
 {
   struct route_node *rn;
   struct ospf_route *or;
   struct listnode *node;

   if ((rn = route_node_lookup (rtrs, (struct prefix *) abr)) == NULL)
     return NULL;

   route_unlock_node (rn);

   for (ALL_LIST_ELEMENTS_RO ((struct list *) rn->info, node, or))
     if (IPV4_ADDR_SAME (&or->u.std.area_id, &area->area_id)
         && (or->u.std.flags & ROUTER_LSA_BORDER))
       return or;

   return NULL;
 }

 static void
 ospf_ia_network_route (struct ospf *ospf, struct route_table *rt,
 		       struct prefix_ipv4 *p, struct ospf_route *new_or,
 		       struct ospf_route *abr_or)
 {
   struct route_node *rn1;
   struct ospf_route *or;

   if (IS_DEBUG_OSPF_EVENT)
     zlog_debug ("ospf_ia_network_route(): processing summary route to %s/%d",
 	       inet_ntoa (p->prefix), p->prefixlen);

   /* Find a route to the same dest */
   if ((rn1 = route_node_lookup (rt, (struct prefix *) p)))
     {
       int res;

       route_unlock_node (rn1);

       if ((or = rn1->info))
 	{
 	  if (IS_DEBUG_OSPF_EVENT)
 	    zlog_debug ("ospf_ia_network_route(): "
 		       "Found a route to the same network");
 	  /* Check the existing route. */
 	  if ((res = ospf_route_cmp (ospf, new_or, or)) < 0)
 	    {
 	      /* New route is better, so replace old one. */
 	      ospf_route_subst (rn1, new_or, abr_or);
 	    }
 	  else if (res == 0)
 	    {
 	      /* New and old route are equal, so next hops can be added. */
 	      route_lock_node (rn1);
 	      ospf_route_copy_nexthops (or, abr_or->paths);
 	      route_unlock_node (rn1);

 	      /* new route can be deleted, because existing route has been updated. */
 	      ospf_route_free (new_or);
 	    }
 	  else
 	    {
 	      /* New route is worse, so free it. */
 	      ospf_route_free (new_or);
 	      return;
 	    }
 	} /* if (or)*/
     } /*if (rn1)*/
   else
     { /* no route */
       if (IS_DEBUG_OSPF_EVENT)
 	zlog_debug ("ospf_ia_network_route(): add new route to %s/%d",
 		   inet_ntoa (p->prefix), p->prefixlen);
       ospf_route_add (rt, p, new_or, abr_or);
     }
 }

 static void
 ospf_ia_router_route (struct ospf *ospf, struct route_table *rtrs,
 		      struct prefix_ipv4 *p,
                       struct ospf_route *new_or, struct ospf_route *abr_or)
 {
   struct ospf_route *or = NULL;
   struct route_node *rn;
   int ret;

   if (IS_DEBUG_OSPF_EVENT)
     zlog_debug ("ospf_ia_router_route(): considering %s/%d",
 	       inet_ntoa (p->prefix), p->prefixlen);
   /* Find a route to the same dest */
   rn = route_node_get (rtrs, (struct prefix *) p);

   if (rn->info == NULL)
     /* This is a new route */
     rn->info = list_new ();
   else
     {
       struct ospf_area *or_area;
       or_area = ospf_area_lookup_by_area_id (ospf, new_or->u.std.area_id);
       assert (or_area);
       /* This is an additional route */
       route_unlock_node (rn);
       or = ospf_find_asbr_route_through_area (rtrs, p, or_area);
     }

   if (or)
     {
       if (IS_DEBUG_OSPF_EVENT)
 	zlog_debug ("ospf_ia_router_route(): "
 		   "a route to the same ABR through the same area exists");
       /* New route is better */
       if ((ret = ospf_route_cmp (ospf, new_or, or)) < 0)
 	{
 	  listnode_delete (rn->info, or);
 	  ospf_route_free (or);
 	  /* proceed down */
 	}
       /* Routes are the same */
       else if (ret == 0)
 	{
 	  if (IS_DEBUG_OSPF_EVENT)
 	    zlog_debug ("ospf_ia_router_route(): merging the new route");

 	  ospf_route_copy_nexthops (or, abr_or->paths);
 	  ospf_route_free (new_or);
 	  return;
 	}
       /* New route is worse */
       else
 	{
 	  if (IS_DEBUG_OSPF_EVENT)
 	    zlog_debug ("ospf_ia_router_route(): skipping the new route");
 	  ospf_route_free (new_or);
 	  return;
 	}
     }

   ospf_route_copy_nexthops (new_or, abr_or->paths);

   if (IS_DEBUG_OSPF_EVENT)
     zlog_debug ("ospf_ia_router_route(): adding the new route");

   listnode_add (rn->info, new_or);
 }


 static int
 process_summary_lsa (struct ospf_area *area, struct route_table *rt,
 		     struct route_table *rtrs, struct ospf_lsa *lsa)
 {
   struct ospf *ospf = area->ospf;
   struct ospf_area_range *range;
   struct ospf_route *abr_or, *new_or;
   struct summary_lsa *sl;
   struct prefix_ipv4 p, abr;
   u_int32_t metric;

   if (lsa == NULL)
     return 0;

   sl = (struct summary_lsa *) lsa->data;

   if (IS_DEBUG_OSPF_EVENT)
     zlog_debug ("process_summary_lsa(): LS ID: %s", inet_ntoa (sl->header.id));

   metric = GET_METRIC (sl->metric);

   if (metric == OSPF_LS_INFINITY)
     return 0;

   if (IS_LSA_MAXAGE (lsa))
     return 0;

   if (ospf_lsa_is_self_originated (area->ospf, lsa))
     return 0;

   p.family = AF_INET;
   p.prefix = sl->header.id;

   if (sl->header.type == OSPF_SUMMARY_LSA)
     p.prefixlen = ip_masklen (sl->mask);
   else
     p.prefixlen = IPV4_MAX_BITLEN;

   apply_mask_ipv4 (&p);

   if (sl->header.type == OSPF_SUMMARY_LSA &&
       (range = ospf_area_range_match_any (ospf, &p)) &&
       ospf_area_range_active (range))
     return 0;

   /* XXX: This check seems dubious to me. If an ABR has already decided
    * to consider summaries received in this area, then why would one wish
    * to exclude default?
    */
   if (IS_OSPF_ABR(ospf) &&
       ospf->abr_type != OSPF_ABR_STAND &&
       area->external_routing != OSPF_AREA_DEFAULT &&
       p.prefix.s_addr == OSPF_DEFAULT_DESTINATION &&
       p.prefixlen == 0)
     return 0; /* Ignore summary default from a stub area */

   abr.family = AF_INET;
   abr.prefix = sl->header.adv_router;
   abr.prefixlen = IPV4_MAX_BITLEN;
   apply_mask_ipv4 (&abr);

   abr_or = ospf_find_abr_route (rtrs, &abr, area);

   if (abr_or == NULL)
     return 0;

   new_or = ospf_route_new ();
   new_or->type = OSPF_DESTINATION_NETWORK;
   new_or->id = sl->header.id;
   new_or->mask = sl->mask;
   new_or->u.std.options = sl->header.options;
   new_or->u.std.origin = (struct lsa_header *) sl;
   new_or->cost = abr_or->cost + metric;
   new_or->u.std.area_id = area->area_id;
   new_or->u.std.external_routing = area->external_routing;
   new_or->path_type = OSPF_PATH_INTER_AREA;

   if (sl->header.type == OSPF_SUMMARY_LSA)
     ospf_ia_network_route (ospf, rt, &p, new_or, abr_or);
   else
     {
       new_or->type = OSPF_DESTINATION_ROUTER;
       new_or->u.std.flags = ROUTER_LSA_EXTERNAL;
       ospf_ia_router_route (ospf, rtrs, &p, new_or, abr_or);
     }

   return 0;
 }

 static void
 ospf_examine_summaries (struct ospf_area *area,
 			struct route_table *lsdb_rt,
                         struct route_table *rt,
                         struct route_table *rtrs)
 {
   struct ospf_lsa *lsa;
   struct route_node *rn;

   LSDB_LOOP (lsdb_rt, rn, lsa)
     process_summary_lsa (area, rt, rtrs, lsa);
 }

 int
 ospf_area_is_transit (struct ospf_area *area)
 {
   return (area->transit == OSPF_TRANSIT_TRUE) ||
     ospf_full_virtual_nbrs(area); /* Cisco forgets to set the V-bit :( */
 }

 static void
 ospf_update_network_route (struct ospf *ospf,
 			   struct route_table *rt,
                            struct route_table *rtrs,
                            struct summary_lsa *lsa,
                            struct prefix_ipv4 *p,
                            struct ospf_area *area)
 {
   struct route_node *rn;
   struct ospf_route *or, *abr_or, *new_or;
   struct prefix_ipv4 abr;
   u_int32_t cost;

   abr.family = AF_INET;
   abr.prefix =lsa->header.adv_router;
   abr.prefixlen = IPV4_MAX_BITLEN;
   apply_mask_ipv4 (&abr);

   abr_or = ospf_find_abr_route (rtrs, &abr, area);

   if (abr_or == NULL)
     {
       if (IS_DEBUG_OSPF_EVENT)
 	zlog_debug ("ospf_update_network_route(): can't find a route to the ABR");
       return;
     }

   cost = abr_or->cost + GET_METRIC (lsa->metric);

   rn = route_node_lookup (rt, (struct prefix *) p);

   if (! rn)
     {
       if (ospf->abr_type != OSPF_ABR_SHORTCUT)
         return; /* Standard ABR can update only already installed
                    backbone paths                                       */
       if (IS_DEBUG_OSPF_EVENT)
 	zlog_debug ("ospf_update_network_route(): "
 		   "Allowing Shortcut ABR to add new route");
       new_or = ospf_route_new ();
       new_or->type = OSPF_DESTINATION_NETWORK;
       new_or->id = lsa->header.id;
       new_or->mask = lsa->mask;
       new_or->u.std.options = lsa->header.options;
       new_or->u.std.origin = (struct lsa_header *) lsa;
       new_or->cost = cost;
       new_or->u.std.area_id = area->area_id;
       new_or->u.std.external_routing = area->external_routing;
       new_or->path_type = OSPF_PATH_INTER_AREA;
       ospf_route_add (rt, p, new_or, abr_or);

       return;
     }
   else
     {
       route_unlock_node (rn);
       if (rn->info == NULL)
         return;
     }

   or = rn->info;

   if (or->path_type != OSPF_PATH_INTRA_AREA &&
       or->path_type != OSPF_PATH_INTER_AREA)
     {
       if (IS_DEBUG_OSPF_EVENT)
 	zlog_debug ("ospf_update_network_route(): ERR: path type is wrong");
       return;
     }

   if (ospf->abr_type == OSPF_ABR_SHORTCUT)
     {
       if (or->path_type == OSPF_PATH_INTRA_AREA &&
 	  !OSPF_IS_AREA_ID_BACKBONE (or->u.std.area_id))
 	{
 	  if (IS_DEBUG_OSPF_EVENT)
 	    zlog_debug ("ospf_update_network_route(): Shortcut: "
 		       "this intra-area path is not backbone");
 	  return;
 	}
     }
   else   /* Not Shortcut ABR */
     {
       if (!OSPF_IS_AREA_ID_BACKBONE (or->u.std.area_id))
 	{
 	  if (IS_DEBUG_OSPF_EVENT)
 	    zlog_debug ("ospf_update_network_route(): "
 		       "route is not BB-associated");
 	  return; /* We can update only BB routes */
 	}
     }

   if (or->cost < cost)
     {
       if (IS_DEBUG_OSPF_EVENT)
 	zlog_debug ("ospf_update_network_route(): new route is worse");
       return;
     }

   if (or->cost == cost)
     {
       if (IS_DEBUG_OSPF_EVENT)
 	zlog_debug ("ospf_update_network_route(): "
 		   "new route is same distance, adding nexthops");
       ospf_route_copy_nexthops (or, abr_or->paths);
     }

   if (or->cost > cost)
     {
       if (IS_DEBUG_OSPF_EVENT)
 	zlog_debug ("ospf_update_network_route(): "
 		   "new route is better, overriding nexthops");
       ospf_route_subst_nexthops (or, abr_or->paths);
       or->cost = cost;

       if ((ospf->abr_type == OSPF_ABR_SHORTCUT) &&
 	  !OSPF_IS_AREA_ID_BACKBONE (or->u.std.area_id))
 	{
 	  or->path_type = OSPF_PATH_INTER_AREA;
 	  or->u.std.area_id = area->area_id;
 	  or->u.std.external_routing = area->external_routing;
           /* Note that we can do this only in Shortcut ABR mode,
              because standard ABR must leave the route type and area
              unchanged
           */
         }
     }
 }

 static void
 ospf_update_router_route (struct ospf *ospf,
 			  struct route_table *rtrs,
                           struct summary_lsa *lsa,
                           struct prefix_ipv4 *p,
                           struct ospf_area *area)
 {
   struct ospf_route *or, *abr_or, *new_or;
   struct prefix_ipv4 abr;
   u_int32_t cost;

   abr.family = AF_INET;
   abr.prefix = lsa->header.adv_router;
   abr.prefixlen = IPV4_MAX_BITLEN;
   apply_mask_ipv4 (&abr);

   abr_or = ospf_find_abr_route (rtrs, &abr, area);

   if (abr_or == NULL)
     {
       if (IS_DEBUG_OSPF_EVENT)
 	zlog_debug ("ospf_update_router_route(): can't find a route to the ABR");
       return;
     }

   cost = abr_or->cost + GET_METRIC (lsa->metric);

   /* First try to find a backbone path,
      because standard ABR can update only BB-associated paths */

   if ((ospf->backbone == NULL) &&
       (ospf->abr_type != OSPF_ABR_SHORTCUT))

      /* no BB area, not Shortcut ABR, exiting */
      return;

   or = ospf_find_asbr_route_through_area (rtrs, p, ospf->backbone);

   if (or == NULL)
     {
       if (ospf->abr_type != OSPF_ABR_SHORTCUT)

          /* route to ASBR through the BB not found
             the router is not Shortcut ABR, exiting */

           return;
       else
 	/* We're a Shortcut ABR*/
 	{
 	  /* Let it either add a new router or update the route
 	     through the same (non-BB) area. */

 	  new_or = ospf_route_new ();
 	  new_or->type = OSPF_DESTINATION_ROUTER;
 	  new_or->id = lsa->header.id;
 	  new_or->mask = lsa->mask;
 	  new_or->u.std.options = lsa->header.options;
 	  new_or->u.std.origin = (struct lsa_header *)lsa;
 	  new_or->cost = cost;
 	  new_or->u.std.area_id = area->area_id;
 	  new_or->u.std.external_routing = area->external_routing;
 	  new_or->path_type = OSPF_PATH_INTER_AREA;
 	  new_or->u.std.flags = ROUTER_LSA_EXTERNAL;
 	  ospf_ia_router_route (ospf, rtrs, p, new_or, abr_or);

           return;
         }
     }

   /* At this point the "or" is always bb-associated */

   if (!(or->u.std.flags & ROUTER_LSA_EXTERNAL))
     {
       if (IS_DEBUG_OSPF_EVENT)
 	zlog_debug ("ospf_upd_router_route(): the remote router is not an ASBR");
       return;
     }

   if (or->path_type != OSPF_PATH_INTRA_AREA &&
       or->path_type != OSPF_PATH_INTER_AREA)
     return;

   if (or->cost < cost)
     return;

   else if (or->cost == cost)
     ospf_route_copy_nexthops (or, abr_or->paths);

   else if (or->cost > cost)
     {
       ospf_route_subst_nexthops (or, abr_or->paths);
       or->cost = cost;

       /* Even if the ABR runs in Shortcut mode, we can't change
          the path type and area, because the "or" is always bb-associated
          at this point and even Shortcut ABR can't change these attributes */
     }
 }

 static int
 process_transit_summary_lsa (struct ospf_area *area, struct route_table *rt,
 			     struct route_table *rtrs, struct ospf_lsa *lsa)
 {
   struct ospf *ospf = area->ospf;
   struct summary_lsa *sl;
   struct prefix_ipv4 p;
   u_int32_t metric;

   if (lsa == NULL)
     return 0;

   sl = (struct summary_lsa *) lsa->data;

   if (IS_DEBUG_OSPF_EVENT)
     zlog_debug ("process_transit_summaries(): LS ID: %s",
 	       inet_ntoa (lsa->data->id));
   metric = GET_METRIC (sl->metric);

   if (metric == OSPF_LS_INFINITY)
     {
       if (IS_DEBUG_OSPF_EVENT)
 	zlog_debug ("process_transit_summaries(): metric is infinity, skip");
       return 0;
     }

   if (IS_LSA_MAXAGE (lsa))
     {
       if (IS_DEBUG_OSPF_EVENT)
 	zlog_debug ("process_transit_summaries(): This LSA is too old");
       return 0;
     }

   if (ospf_lsa_is_self_originated (area->ospf, lsa))
     {
       if (IS_DEBUG_OSPF_EVENT)
 	zlog_debug ("process_transit_summaries(): This LSA is mine, skip");
       return 0;
     }

   p.family = AF_INET;
   p.prefix = sl->header.id;

   if (sl->header.type == OSPF_SUMMARY_LSA)
     p.prefixlen = ip_masklen (sl->mask);
   else
     p.prefixlen = IPV4_MAX_BITLEN;

   apply_mask_ipv4 (&p);

   if (sl->header.type == OSPF_SUMMARY_LSA)
     ospf_update_network_route (ospf, rt, rtrs, sl, &p, area);
   else
     ospf_update_router_route (ospf, rtrs, sl, &p, area);

   return 0;
 }

 static void
 ospf_examine_transit_summaries (struct ospf_area *area,
 				struct route_table *lsdb_rt,
                                 struct route_table *rt,
                                 struct route_table *rtrs)
 {
   struct ospf_lsa *lsa;
   struct route_node *rn;

   LSDB_LOOP (lsdb_rt, rn, lsa)
     process_transit_summary_lsa (area, rt, rtrs, lsa);
 }

 void
 ospf_ia_routing (struct ospf *ospf,
 		 struct route_table *rt,
                  struct route_table *rtrs)
 {
   struct ospf_area * area;

   if (IS_DEBUG_OSPF_EVENT)
     zlog_debug ("ospf_ia_routing():start");

   if (IS_OSPF_ABR (ospf))
     {
       struct listnode *node;
       struct ospf_area *area;

       switch (ospf->abr_type)
         {
         case OSPF_ABR_STAND:
 	  if (IS_DEBUG_OSPF_EVENT)
 	    zlog_debug ("ospf_ia_routing():Standard ABR");

           if ((area = ospf->backbone))
             {
               struct listnode *node;

 	      if (IS_DEBUG_OSPF_EVENT)
 		{
 		  zlog_debug ("ospf_ia_routing():backbone area found");
 		  zlog_debug ("ospf_ia_routing():examining summaries");
 		}

               OSPF_EXAMINE_SUMMARIES_ALL (area, rt, rtrs);

 	      for (ALL_LIST_ELEMENTS_RO (ospf->areas, node, area))
                 if (area != ospf->backbone)
                   if (ospf_area_is_transit (area))
                     OSPF_EXAMINE_TRANSIT_SUMMARIES_ALL (area, rt, rtrs);
             }
           else
 	    if (IS_DEBUG_OSPF_EVENT)
 	      zlog_debug ("ospf_ia_routing():backbone area NOT found");
           break;
         case OSPF_ABR_IBM:
         case OSPF_ABR_CISCO:
 	  if (IS_DEBUG_OSPF_EVENT)
 	    zlog_debug ("ospf_ia_routing():Alternative Cisco/IBM ABR");
           area = ospf->backbone; /* Find the BB */

           /* If we have an active BB connection */
           if (area && ospf_act_bb_connection (ospf))
             {
 	      if (IS_DEBUG_OSPF_EVENT)
 		{
 		  zlog_debug ("ospf_ia_routing(): backbone area found");
 		  zlog_debug ("ospf_ia_routing(): examining BB summaries");
 		}

               OSPF_EXAMINE_SUMMARIES_ALL (area, rt, rtrs);

 	      for (ALL_LIST_ELEMENTS_RO (ospf->areas, node, area))
                 if (area != ospf->backbone)
                   if (ospf_area_is_transit (area))
                     OSPF_EXAMINE_TRANSIT_SUMMARIES_ALL (area, rt, rtrs);
             }
           else
             { /* No active BB connection--consider all areas */
 	      if (IS_DEBUG_OSPF_EVENT)
 		zlog_debug ("ospf_ia_routing(): "
 			   "Active BB connection not found");
 	      for (ALL_LIST_ELEMENTS_RO (ospf->areas, node, area))
                 OSPF_EXAMINE_SUMMARIES_ALL (area, rt, rtrs);
             }
           break;
         case OSPF_ABR_SHORTCUT:
 	  if (IS_DEBUG_OSPF_EVENT)
 	    zlog_debug ("ospf_ia_routing():Alternative Shortcut");
           area = ospf->backbone; /* Find the BB */

           /* If we have an active BB connection */
           if (area && ospf_act_bb_connection (ospf))
             {
 	      if (IS_DEBUG_OSPF_EVENT)
 		{
 		  zlog_debug ("ospf_ia_routing(): backbone area found");
 		  zlog_debug ("ospf_ia_routing(): examining BB summaries");
 		}
               OSPF_EXAMINE_SUMMARIES_ALL (area, rt, rtrs);
             }

 	  for (ALL_LIST_ELEMENTS_RO (ospf->areas, node, area))
             if (area != ospf->backbone)
               if (ospf_area_is_transit (area) ||
                   ((area->shortcut_configured != OSPF_SHORTCUT_DISABLE) &&
                   ((ospf->backbone == NULL) ||
                   ((area->shortcut_configured == OSPF_SHORTCUT_ENABLE) &&
                   area->shortcut_capability))))
                 OSPF_EXAMINE_TRANSIT_SUMMARIES_ALL (area, rt, rtrs);
           break;
         default:
           break;
         }
     }
   else
     {
       struct listnode *node;

       if (IS_DEBUG_OSPF_EVENT)
 	zlog_debug ("ospf_ia_routing():not ABR, considering all areas");

       for (ALL_LIST_ELEMENTS_RO (ospf->areas, node, area))
         OSPF_EXAMINE_SUMMARIES_ALL (area, rt, rtrs);
     }
 }
	/*
	* OSPF inter-area routing.
	* Copyright (C) 1999, 2000 Alex Zinin, Toshiaki Takada
	*
	* This file is part of GNU Zebra.
	*
	* GNU Zebra is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License as published by the
	* Free Software Foundation; either version 2, or (at your option) any
	* later version.
	*
	* GNU Zebra is distributed in the hope that it will be useful, but
	* WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	* General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with GNU Zebra; see the file COPYING. If not, write to the Free
	* Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
	* 02111-1307, USA.
	*/


	#include <zebra.h>

	#include "thread.h"
	#include "memory.h"
	#include "hash.h"
	#include "linklist.h"
	#include "prefix.h"
	#include "table.h"
	#include "log.h"

	#include "ospfd/ospfd.h"
	#include "ospfd/ospf_interface.h"
	#include "ospfd/ospf_ism.h"
	#include "ospfd/ospf_asbr.h"
	#include "ospfd/ospf_lsa.h"
	#include "ospfd/ospf_lsdb.h"
	#include "ospfd/ospf_neighbor.h"
	#include "ospfd/ospf_nsm.h"
	#include "ospfd/ospf_spf.h"
	#include "ospfd/ospf_route.h"
	#include "ospfd/ospf_ase.h"
	#include "ospfd/ospf_abr.h"
	#include "ospfd/ospf_ia.h"
	#include "ospfd/ospf_dump.h"

	#define DEBUG

	static struct ospf_route *
	ospf_find_abr_route (struct route_table *rtrs,
	struct prefix_ipv4 *abr,
	struct ospf_area *area)
	{
	struct route_node *rn;
	struct ospf_route *or;
	struct listnode *node;

	if ((rn = route_node_lookup (rtrs, (struct prefix *) abr)) == NULL)
	return NULL;

	route_unlock_node (rn);

	for (ALL_LIST_ELEMENTS_RO ((struct list *) rn->info, node, or))
	if (IPV4_ADDR_SAME (&or->u.std.area_id, &area->area_id)
	&& (or->u.std.flags & ROUTER_LSA_BORDER))
	return or;

	return NULL;
	}

	static void
	ospf_ia_network_route (struct ospf ospf, struct route_table rt,
	struct prefix_ipv4 p, struct ospf_route new_or,
	struct ospf_route *abr_or)
	{
	struct route_node *rn1;
	struct ospf_route *or;

	if (IS_DEBUG_OSPF_EVENT)
	zlog_debug ("ospf_ia_network_route(): processing summary route to %s/%d",
	inet_ntoa (p->prefix), p->prefixlen);

	/* Find a route to the same dest */
	if ((rn1 = route_node_lookup (rt, (struct prefix *) p)))
	{
	int res;

	route_unlock_node (rn1);

	if ((or = rn1->info))
	{
	if (IS_DEBUG_OSPF_EVENT)
	zlog_debug ("ospf_ia_network_route(): "
	"Found a route to the same network");
	/* Check the existing route. */
	if ((res = ospf_route_cmp (ospf, new_or, or)) < 0)
	{
	/* New route is better, so replace old one. */
	ospf_route_subst (rn1, new_or, abr_or);
	}
	else if (res == 0)
	{
	/* New and old route are equal, so next hops can be added. */
	route_lock_node (rn1);
	ospf_route_copy_nexthops (or, abr_or->paths);
	route_unlock_node (rn1);

	/* new route can be deleted, because existing route has been updated. */
	ospf_route_free (new_or);
	}
	else
	{
	/* New route is worse, so free it. */
	ospf_route_free (new_or);
	return;
	}
	} /* if (or)*/
	} /if (rn1)/
	else
	{ /* no route */
	if (IS_DEBUG_OSPF_EVENT)
	zlog_debug ("ospf_ia_network_route(): add new route to %s/%d",
	inet_ntoa (p->prefix), p->prefixlen);
	ospf_route_add (rt, p, new_or, abr_or);
	}
	}

	static void
	ospf_ia_router_route (struct ospf ospf, struct route_table rtrs,
	struct prefix_ipv4 *p,
	struct ospf_route new_or, struct ospf_route abr_or)
	{
	struct ospf_route *or = NULL;
	struct route_node *rn;
	int ret;

	if (IS_DEBUG_OSPF_EVENT)
	zlog_debug ("ospf_ia_router_route(): considering %s/%d",
	inet_ntoa (p->prefix), p->prefixlen);
	/* Find a route to the same dest */
	rn = route_node_get (rtrs, (struct prefix *) p);

	if (rn->info == NULL)
	/* This is a new route */
	rn->info = list_new ();
	else
	{
	struct ospf_area *or_area;
	or_area = ospf_area_lookup_by_area_id (ospf, new_or->u.std.area_id);
	assert (or_area);
	/* This is an additional route */
	route_unlock_node (rn);
	or = ospf_find_asbr_route_through_area (rtrs, p, or_area);
	}

	if (or)
	{
	if (IS_DEBUG_OSPF_EVENT)
	zlog_debug ("ospf_ia_router_route(): "
	"a route to the same ABR through the same area exists");
	/* New route is better */
	if ((ret = ospf_route_cmp (ospf, new_or, or)) < 0)
	{
	listnode_delete (rn->info, or);
	ospf_route_free (or);
	/* proceed down */
	}
	/* Routes are the same */
	else if (ret == 0)
	{
	if (IS_DEBUG_OSPF_EVENT)
	zlog_debug ("ospf_ia_router_route(): merging the new route");

	ospf_route_copy_nexthops (or, abr_or->paths);
	ospf_route_free (new_or);
	return;
	}
	/* New route is worse */
	else
	{
	if (IS_DEBUG_OSPF_EVENT)
	zlog_debug ("ospf_ia_router_route(): skipping the new route");
	ospf_route_free (new_or);
	return;
	}
	}

	ospf_route_copy_nexthops (new_or, abr_or->paths);

	if (IS_DEBUG_OSPF_EVENT)
	zlog_debug ("ospf_ia_router_route(): adding the new route");

	listnode_add (rn->info, new_or);
	}


	static int
	process_summary_lsa (struct ospf_area area, struct route_table rt,
	struct route_table rtrs, struct ospf_lsa lsa)
	{
	struct ospf *ospf = area->ospf;
	struct ospf_area_range *range;
	struct ospf_route abr_or, new_or;
	struct summary_lsa *sl;
	struct prefix_ipv4 p, abr;
	u_int32_t metric;

	if (lsa == NULL)
	return 0;

	sl = (struct summary_lsa *) lsa->data;

	if (IS_DEBUG_OSPF_EVENT)
	zlog_debug ("process_summary_lsa(): LS ID: %s", inet_ntoa (sl->header.id));

	metric = GET_METRIC (sl->metric);

	if (metric == OSPF_LS_INFINITY)
	return 0;

	if (IS_LSA_MAXAGE (lsa))
	return 0;

	if (ospf_lsa_is_self_originated (area->ospf, lsa))
	return 0;

	p.family = AF_INET;
	p.prefix = sl->header.id;

	if (sl->header.type == OSPF_SUMMARY_LSA)
	p.prefixlen = ip_masklen (sl->mask);
	else
	p.prefixlen = IPV4_MAX_BITLEN;

	apply_mask_ipv4 (&p);

	if (sl->header.type == OSPF_SUMMARY_LSA &&
	(range = ospf_area_range_match_any (ospf, &p)) &&
	ospf_area_range_active (range))
	return 0;

	/* XXX: This check seems dubious to me. If an ABR has already decided
	* to consider summaries received in this area, then why would one wish
	* to exclude default?
	*/
	if (IS_OSPF_ABR(ospf) &&
	ospf->abr_type != OSPF_ABR_STAND &&
	area->external_routing != OSPF_AREA_DEFAULT &&
	p.prefix.s_addr == OSPF_DEFAULT_DESTINATION &&
	p.prefixlen == 0)
	return 0; /* Ignore summary default from a stub area */

	abr.family = AF_INET;
	abr.prefix = sl->header.adv_router;
	abr.prefixlen = IPV4_MAX_BITLEN;
	apply_mask_ipv4 (&abr);

	abr_or = ospf_find_abr_route (rtrs, &abr, area);

	if (abr_or == NULL)
	return 0;

	new_or = ospf_route_new ();
	new_or->type = OSPF_DESTINATION_NETWORK;
	new_or->id = sl->header.id;
	new_or->mask = sl->mask;
	new_or->u.std.options = sl->header.options;
	new_or->u.std.origin = (struct lsa_header *) sl;
	new_or->cost = abr_or->cost + metric;
	new_or->u.std.area_id = area->area_id;
	new_or->u.std.external_routing = area->external_routing;
	new_or->path_type = OSPF_PATH_INTER_AREA;

	if (sl->header.type == OSPF_SUMMARY_LSA)
	ospf_ia_network_route (ospf, rt, &p, new_or, abr_or);
	else
	{
	new_or->type = OSPF_DESTINATION_ROUTER;
	new_or->u.std.flags = ROUTER_LSA_EXTERNAL;
	ospf_ia_router_route (ospf, rtrs, &p, new_or, abr_or);
	}

	return 0;
	}

	static void
	ospf_examine_summaries (struct ospf_area *area,
	struct route_table *lsdb_rt,
	struct route_table *rt,
	struct route_table *rtrs)
	{
	struct ospf_lsa *lsa;
	struct route_node *rn;

	LSDB_LOOP (lsdb_rt, rn, lsa)
	process_summary_lsa (area, rt, rtrs, lsa);
	}

	int
	ospf_area_is_transit (struct ospf_area *area)
	{
	return (area->transit == OSPF_TRANSIT_TRUE) \|\|
	ospf_full_virtual_nbrs(area); /* Cisco forgets to set the V-bit :( */
	}

	static void
	ospf_update_network_route (struct ospf *ospf,
	struct route_table *rt,
	struct route_table *rtrs,
	struct summary_lsa *lsa,
	struct prefix_ipv4 *p,
	struct ospf_area *area)
	{
	struct route_node *rn;
	struct ospf_route or, abr_or, *new_or;
	struct prefix_ipv4 abr;
	u_int32_t cost;

	abr.family = AF_INET;
	abr.prefix =lsa->header.adv_router;
	abr.prefixlen = IPV4_MAX_BITLEN;
	apply_mask_ipv4 (&abr);

	abr_or = ospf_find_abr_route (rtrs, &abr, area);

	if (abr_or == NULL)
	{
	if (IS_DEBUG_OSPF_EVENT)
	zlog_debug ("ospf_update_network_route(): can't find a route to the ABR");
	return;
	}

	cost = abr_or->cost + GET_METRIC (lsa->metric);

	rn = route_node_lookup (rt, (struct prefix *) p);

	if (! rn)
	{
	if (ospf->abr_type != OSPF_ABR_SHORTCUT)
	return; /* Standard ABR can update only already installed
	backbone paths */
	if (IS_DEBUG_OSPF_EVENT)
	zlog_debug ("ospf_update_network_route(): "
	"Allowing Shortcut ABR to add new route");
	new_or = ospf_route_new ();
	new_or->type = OSPF_DESTINATION_NETWORK;
	new_or->id = lsa->header.id;
	new_or->mask = lsa->mask;
	new_or->u.std.options = lsa->header.options;
	new_or->u.std.origin = (struct lsa_header *) lsa;
	new_or->cost = cost;
	new_or->u.std.area_id = area->area_id;
	new_or->u.std.external_routing = area->external_routing;
	new_or->path_type = OSPF_PATH_INTER_AREA;
	ospf_route_add (rt, p, new_or, abr_or);

	return;
	}
	else
	{
	route_unlock_node (rn);
	if (rn->info == NULL)
	return;
	}

	or = rn->info;

	if (or->path_type != OSPF_PATH_INTRA_AREA &&
	or->path_type != OSPF_PATH_INTER_AREA)
	{
	if (IS_DEBUG_OSPF_EVENT)
	zlog_debug ("ospf_update_network_route(): ERR: path type is wrong");
	return;
	}

	if (ospf->abr_type == OSPF_ABR_SHORTCUT)
	{
	if (or->path_type == OSPF_PATH_INTRA_AREA &&
	!OSPF_IS_AREA_ID_BACKBONE (or->u.std.area_id))
	{
	if (IS_DEBUG_OSPF_EVENT)
	zlog_debug ("ospf_update_network_route(): Shortcut: "
	"this intra-area path is not backbone");
	return;
	}
	}
	else /* Not Shortcut ABR */
	{
	if (!OSPF_IS_AREA_ID_BACKBONE (or->u.std.area_id))
	{
	if (IS_DEBUG_OSPF_EVENT)
	zlog_debug ("ospf_update_network_route(): "
	"route is not BB-associated");
	return; /* We can update only BB routes */
	}
	}

	if (or->cost < cost)
	{
	if (IS_DEBUG_OSPF_EVENT)
	zlog_debug ("ospf_update_network_route(): new route is worse");
	return;
	}

	if (or->cost == cost)
	{
	if (IS_DEBUG_OSPF_EVENT)
	zlog_debug ("ospf_update_network_route(): "
	"new route is same distance, adding nexthops");
	ospf_route_copy_nexthops (or, abr_or->paths);
	}

	if (or->cost > cost)
	{
	if (IS_DEBUG_OSPF_EVENT)
	zlog_debug ("ospf_update_network_route(): "
	"new route is better, overriding nexthops");
	ospf_route_subst_nexthops (or, abr_or->paths);
	or->cost = cost;

	if ((ospf->abr_type == OSPF_ABR_SHORTCUT) &&
	!OSPF_IS_AREA_ID_BACKBONE (or->u.std.area_id))
	{
	or->path_type = OSPF_PATH_INTER_AREA;
	or->u.std.area_id = area->area_id;
	or->u.std.external_routing = area->external_routing;
	/* Note that we can do this only in Shortcut ABR mode,
	because standard ABR must leave the route type and area
	unchanged
	*/
	}
	}
	}

	static void
	ospf_update_router_route (struct ospf *ospf,
	struct route_table *rtrs,
	struct summary_lsa *lsa,
	struct prefix_ipv4 *p,
	struct ospf_area *area)
	{
	struct ospf_route or, abr_or, *new_or;
	struct prefix_ipv4 abr;
	u_int32_t cost;

	abr.family = AF_INET;
	abr.prefix = lsa->header.adv_router;
	abr.prefixlen = IPV4_MAX_BITLEN;
	apply_mask_ipv4 (&abr);

	abr_or = ospf_find_abr_route (rtrs, &abr, area);

	if (abr_or == NULL)
	{
	if (IS_DEBUG_OSPF_EVENT)
	zlog_debug ("ospf_update_router_route(): can't find a route to the ABR");
	return;
	}

	cost = abr_or->cost + GET_METRIC (lsa->metric);

	/* First try to find a backbone path,
	because standard ABR can update only BB-associated paths */

	if ((ospf->backbone == NULL) &&
	(ospf->abr_type != OSPF_ABR_SHORTCUT))

	/* no BB area, not Shortcut ABR, exiting */
	return;

	or = ospf_find_asbr_route_through_area (rtrs, p, ospf->backbone);

	if (or == NULL)
	{
	if (ospf->abr_type != OSPF_ABR_SHORTCUT)

	/* route to ASBR through the BB not found
	the router is not Shortcut ABR, exiting */

	return;
	else
	/* We're a Shortcut ABR*/
	{
	/* Let it either add a new router or update the route
	through the same (non-BB) area. */

	new_or = ospf_route_new ();
	new_or->type = OSPF_DESTINATION_ROUTER;
	new_or->id = lsa->header.id;
	new_or->mask = lsa->mask;
	new_or->u.std.options = lsa->header.options;
	new_or->u.std.origin = (struct lsa_header *)lsa;
	new_or->cost = cost;
	new_or->u.std.area_id = area->area_id;
	new_or->u.std.external_routing = area->external_routing;
	new_or->path_type = OSPF_PATH_INTER_AREA;
	new_or->u.std.flags = ROUTER_LSA_EXTERNAL;
	ospf_ia_router_route (ospf, rtrs, p, new_or, abr_or);

	return;
	}
	}

	/* At this point the "or" is always bb-associated */

	if (!(or->u.std.flags & ROUTER_LSA_EXTERNAL))
	{
	if (IS_DEBUG_OSPF_EVENT)
	zlog_debug ("ospf_upd_router_route(): the remote router is not an ASBR");
	return;
	}

	if (or->path_type != OSPF_PATH_INTRA_AREA &&
	or->path_type != OSPF_PATH_INTER_AREA)
	return;

	if (or->cost < cost)
	return;

	else if (or->cost == cost)
	ospf_route_copy_nexthops (or, abr_or->paths);

	else if (or->cost > cost)
	{
	ospf_route_subst_nexthops (or, abr_or->paths);
	or->cost = cost;

	/* Even if the ABR runs in Shortcut mode, we can't change
	the path type and area, because the "or" is always bb-associated
	at this point and even Shortcut ABR can't change these attributes */
	}
	}

	static int
	process_transit_summary_lsa (struct ospf_area area, struct route_table rt,
	struct route_table rtrs, struct ospf_lsa lsa)
	{
	struct ospf *ospf = area->ospf;
	struct summary_lsa *sl;
	struct prefix_ipv4 p;
	u_int32_t metric;

	if (lsa == NULL)
	return 0;

	sl = (struct summary_lsa *) lsa->data;

	if (IS_DEBUG_OSPF_EVENT)
	zlog_debug ("process_transit_summaries(): LS ID: %s",
	inet_ntoa (lsa->data->id));
	metric = GET_METRIC (sl->metric);

	if (metric == OSPF_LS_INFINITY)
	{
	if (IS_DEBUG_OSPF_EVENT)
	zlog_debug ("process_transit_summaries(): metric is infinity, skip");
	return 0;
	}

	if (IS_LSA_MAXAGE (lsa))
	{
	if (IS_DEBUG_OSPF_EVENT)
	zlog_debug ("process_transit_summaries(): This LSA is too old");
	return 0;
	}

	if (ospf_lsa_is_self_originated (area->ospf, lsa))
	{
	if (IS_DEBUG_OSPF_EVENT)
	zlog_debug ("process_transit_summaries(): This LSA is mine, skip");
	return 0;
	}

	p.family = AF_INET;
	p.prefix = sl->header.id;

	if (sl->header.type == OSPF_SUMMARY_LSA)
	p.prefixlen = ip_masklen (sl->mask);
	else
	p.prefixlen = IPV4_MAX_BITLEN;

	apply_mask_ipv4 (&p);

	if (sl->header.type == OSPF_SUMMARY_LSA)
	ospf_update_network_route (ospf, rt, rtrs, sl, &p, area);
	else
	ospf_update_router_route (ospf, rtrs, sl, &p, area);

	return 0;
	}

	static void
	ospf_examine_transit_summaries (struct ospf_area *area,
	struct route_table *lsdb_rt,
	struct route_table *rt,
	struct route_table *rtrs)
	{
	struct ospf_lsa *lsa;
	struct route_node *rn;

	LSDB_LOOP (lsdb_rt, rn, lsa)
	process_transit_summary_lsa (area, rt, rtrs, lsa);
	}

	void
	ospf_ia_routing (struct ospf *ospf,
	struct route_table *rt,
	struct route_table *rtrs)
	{
	struct ospf_area * area;

	if (IS_DEBUG_OSPF_EVENT)
	zlog_debug ("ospf_ia_routing():start");

	if (IS_OSPF_ABR (ospf))
	{
	struct listnode *node;
	struct ospf_area *area;

	switch (ospf->abr_type)
	{
	case OSPF_ABR_STAND:
	if (IS_DEBUG_OSPF_EVENT)
	zlog_debug ("ospf_ia_routing():Standard ABR");

	if ((area = ospf->backbone))
	{
	struct listnode *node;

	if (IS_DEBUG_OSPF_EVENT)
	{
	zlog_debug ("ospf_ia_routing():backbone area found");
	zlog_debug ("ospf_ia_routing():examining summaries");
	}

	OSPF_EXAMINE_SUMMARIES_ALL (area, rt, rtrs);

	for (ALL_LIST_ELEMENTS_RO (ospf->areas, node, area))
	if (area != ospf->backbone)
	if (ospf_area_is_transit (area))
	OSPF_EXAMINE_TRANSIT_SUMMARIES_ALL (area, rt, rtrs);
	}
	else
	if (IS_DEBUG_OSPF_EVENT)
	zlog_debug ("ospf_ia_routing():backbone area NOT found");
	break;
	case OSPF_ABR_IBM:
	case OSPF_ABR_CISCO:
	if (IS_DEBUG_OSPF_EVENT)
	zlog_debug ("ospf_ia_routing():Alternative Cisco/IBM ABR");
	area = ospf->backbone; /* Find the BB */

	/* If we have an active BB connection */
	if (area && ospf_act_bb_connection (ospf))
	{
	if (IS_DEBUG_OSPF_EVENT)
	{
	zlog_debug ("ospf_ia_routing(): backbone area found");
	zlog_debug ("ospf_ia_routing(): examining BB summaries");
	}

	OSPF_EXAMINE_SUMMARIES_ALL (area, rt, rtrs);

	for (ALL_LIST_ELEMENTS_RO (ospf->areas, node, area))
	if (area != ospf->backbone)
	if (ospf_area_is_transit (area))
	OSPF_EXAMINE_TRANSIT_SUMMARIES_ALL (area, rt, rtrs);
	}
	else
	{ /* No active BB connection--consider all areas */
	if (IS_DEBUG_OSPF_EVENT)
	zlog_debug ("ospf_ia_routing(): "
	"Active BB connection not found");
	for (ALL_LIST_ELEMENTS_RO (ospf->areas, node, area))
	OSPF_EXAMINE_SUMMARIES_ALL (area, rt, rtrs);
	}
	break;
	case OSPF_ABR_SHORTCUT:
	if (IS_DEBUG_OSPF_EVENT)
	zlog_debug ("ospf_ia_routing():Alternative Shortcut");
	area = ospf->backbone; /* Find the BB */

	/* If we have an active BB connection */
	if (area && ospf_act_bb_connection (ospf))
	{
	if (IS_DEBUG_OSPF_EVENT)
	{
	zlog_debug ("ospf_ia_routing(): backbone area found");
	zlog_debug ("ospf_ia_routing(): examining BB summaries");
	}
	OSPF_EXAMINE_SUMMARIES_ALL (area, rt, rtrs);
	}

	for (ALL_LIST_ELEMENTS_RO (ospf->areas, node, area))
	if (area != ospf->backbone)
	if (ospf_area_is_transit (area) \|\|
	((area->shortcut_configured != OSPF_SHORTCUT_DISABLE) &&
	((ospf->backbone == NULL) \|\|
	((area->shortcut_configured == OSPF_SHORTCUT_ENABLE) &&
	area->shortcut_capability))))
	OSPF_EXAMINE_TRANSIT_SUMMARIES_ALL (area, rt, rtrs);
	break;
	default:
	break;
	}
	}
	else
	{
	struct listnode *node;

	if (IS_DEBUG_OSPF_EVENT)
	zlog_debug ("ospf_ia_routing():not ABR, considering all areas");

	for (ALL_LIST_ELEMENTS_RO (ospf->areas, node, area))
	OSPF_EXAMINE_SUMMARIES_ALL (area, rt, rtrs);
	}
	}