ospf6d: ospfv3-abr-ecmp-support.patch

[mirror_frr.git] / ospf6d / ospf6_abr.c

/*
 * Area Border Router function.
 * Copyright (C) 2004 Yasuhiro Ohara
 *
 * 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 "log.h"
#include "prefix.h"
#include "table.h"
#include "vty.h"
#include "linklist.h"
#include "command.h"
#include "thread.h"
#include "plist.h"
#include "filter.h"

#include "ospf6_proto.h"
#include "ospf6_route.h"
#include "ospf6_lsa.h"
#include "ospf6_route.h"
#include "ospf6_lsdb.h"
#include "ospf6_message.h"
#include "ospf6_zebra.h"

#include "ospf6_top.h"
#include "ospf6_area.h"
#include "ospf6_interface.h"
#include "ospf6_neighbor.h"

#include "ospf6_flood.h"
#include "ospf6_intra.h"
#include "ospf6_abr.h"
#include "ospf6d.h"

unsigned char conf_debug_ospf6_abr;

int
ospf6_is_router_abr (struct ospf6 *o)
{
  struct listnode *node;
  struct ospf6_area *oa;
  int area_count = 0;

  for (ALL_LIST_ELEMENTS_RO (o->area_list, node, oa))
    if (IS_AREA_ENABLED (oa))
      area_count++;

  if (area_count > 1)
    return 1;
  return 0;
}

static int
ospf6_abr_nexthops_belong_to_area (struct ospf6_route *route,
				   struct ospf6_area *area)
{
  struct ospf6_interface *oi;

  oi = ospf6_interface_lookup_by_ifindex (ospf6_route_get_first_nh_index(route));
  if (oi && oi->area && oi->area == area)
    return 1;
  else
    return 0;
}

static void
ospf6_abr_delete_route (struct ospf6_route *range, struct ospf6_route *summary,
			struct ospf6_route_table *summary_table,
			struct ospf6_lsa *old)
{
  if (summary)
    {
      ospf6_route_remove (summary, summary_table);
    }

  if (old)
    ospf6_lsa_purge (old);
}

void
ospf6_abr_enable_area (struct ospf6_area *area)
{
  struct ospf6_area *oa;
  struct ospf6_route *ro;
  struct listnode *node, *nnode;

  for (ALL_LIST_ELEMENTS (area->ospf6->area_list, node, nnode, oa))
    {
      /* update B bit for each area */
      OSPF6_ROUTER_LSA_SCHEDULE (oa);

      /* install other area's configured address range */
      if (oa != area)
        {
          for (ro = ospf6_route_head (oa->range_table); ro;
               ro = ospf6_route_next (ro))
            {
              if (CHECK_FLAG (ro->flag, OSPF6_ROUTE_ACTIVE_SUMMARY))
                ospf6_abr_originate_summary_to_area (ro, area);
            }
        }
    }

  /* install calculated routes to border routers */
  for (ro = ospf6_route_head (area->ospf6->brouter_table); ro;
       ro = ospf6_route_next (ro))
    ospf6_abr_originate_summary_to_area (ro, area);

  /* install calculated routes to network (may be rejected by ranges) */
  for (ro = ospf6_route_head (area->ospf6->route_table); ro;
       ro = ospf6_route_next (ro))
    ospf6_abr_originate_summary_to_area (ro, area);
}

void
ospf6_abr_disable_area (struct ospf6_area *area)
{
  struct ospf6_area *oa;
  struct ospf6_route *ro;
  struct ospf6_lsa *old;
  struct listnode *node, *nnode;

  /* Withdraw all summary prefixes previously originated */
  for (ro = ospf6_route_head (area->summary_prefix); ro;
       ro = ospf6_route_next (ro))
    {
      old = ospf6_lsdb_lookup (ro->path.origin.type, ro->path.origin.id,
                               area->ospf6->router_id, area->lsdb);
      if (old)
        ospf6_lsa_purge (old);
      ospf6_route_remove (ro, area->summary_prefix);
    }

  /* Withdraw all summary router-routes previously originated */
  for (ro = ospf6_route_head (area->summary_router); ro;
       ro = ospf6_route_next (ro))
    {
      old = ospf6_lsdb_lookup (ro->path.origin.type, ro->path.origin.id,
                               area->ospf6->router_id, area->lsdb);
      if (old)
        ospf6_lsa_purge (old);
      ospf6_route_remove (ro, area->summary_router);
    }

  /* Schedule Router-LSA for each area (ABR status may change) */
  for (ALL_LIST_ELEMENTS (area->ospf6->area_list, node, nnode, oa))
    /* update B bit for each area */
    OSPF6_ROUTER_LSA_SCHEDULE (oa);
}

/* RFC 2328 12.4.3. Summary-LSAs */
int
ospf6_abr_originate_summary_to_area (struct ospf6_route *route,
                                     struct ospf6_area *area)
{
  struct ospf6_lsa *lsa, *old = NULL;
  struct ospf6_route *summary, *range = NULL;
  struct ospf6_area *route_area;
  char buffer[OSPF6_MAX_LSASIZE];
  struct ospf6_lsa_header *lsa_header;
  caddr_t p;
  struct ospf6_inter_prefix_lsa *prefix_lsa;
  struct ospf6_inter_router_lsa *router_lsa;
  struct ospf6_route_table *summary_table = NULL;
  u_int16_t type;
  char buf[64];
  int is_debug = 0;

  /* Only destination type network, range or ASBR are considered */
  if (route->type != OSPF6_DEST_TYPE_NETWORK &&
      route->type != OSPF6_DEST_TYPE_RANGE &&
      ((route->type != OSPF6_DEST_TYPE_ROUTER) ||
       !CHECK_FLAG (route->path.router_bits, OSPF6_ROUTER_BIT_E)))
    {
      if (is_debug)
        zlog_debug ("Route type is none of network, range nor ASBR, ignore");
      return 0;
    }

  /* AS External routes are never considered */
  if (route->path.type == OSPF6_PATH_TYPE_EXTERNAL1 ||
      route->path.type == OSPF6_PATH_TYPE_EXTERNAL2)
    {
      if (is_debug)
        zlog_debug ("Path type is external, skip");
      return 0;
    }

  /* do not generate if the path's area is the same as target area */
  if (route->path.area_id == area->area_id)
    {
      if (is_debug)
        zlog_debug ("The route is in the area itself, ignore");
      return 0;
    }

  /* do not generate if the nexthops belongs to the target area */
  if (ospf6_abr_nexthops_belong_to_area (route, area))
    {
      if (is_debug)
        zlog_debug ("The route's nexthop is in the same area, ignore");
      return 0;
    }

  if (route->type == OSPF6_DEST_TYPE_ROUTER)
    {
      if (ADV_ROUTER_IN_PREFIX (&route->prefix) == area->ospf6->router_id)
	{
          inet_ntop (AF_INET, &(ADV_ROUTER_IN_PREFIX (&route->prefix)), buf,
		     sizeof (buf));
	  zlog_debug ("%s: Skipping ASBR announcement for ABR (%s)", __func__,
		      buf);
	  return 0;
	}
    }

  if (route->type == OSPF6_DEST_TYPE_ROUTER)
    {
      if (IS_OSPF6_DEBUG_ABR || IS_OSPF6_DEBUG_ORIGINATE (INTER_ROUTER))
        {
          is_debug++;
          inet_ntop (AF_INET, &(ADV_ROUTER_IN_PREFIX (&route->prefix)),
                     buf, sizeof (buf));
          zlog_debug ("Originating summary in area %s for ASBR %s",
		      area->name, buf);
        }
      summary_table = area->summary_router;
    }
  else
    {
      if (IS_OSPF6_DEBUG_ABR || IS_OSPF6_DEBUG_ORIGINATE (INTER_PREFIX))
        {
          is_debug++;
          prefix2str (&route->prefix, buf, sizeof (buf));
          zlog_debug ("Originating summary in area %s for %s",
		      area->name, buf);
        }
      summary_table = area->summary_prefix;
    }

  summary = ospf6_route_lookup (&route->prefix, summary_table);
  if (summary)
    old = ospf6_lsdb_lookup (summary->path.origin.type,
                             summary->path.origin.id,
                             area->ospf6->router_id, area->lsdb);

  /* if this route has just removed, remove corresponding LSA */
  if (CHECK_FLAG (route->flag, OSPF6_ROUTE_REMOVE))
    {
      if (is_debug)
        zlog_debug ("The route has just removed, purge previous LSA");

      if (route->type == OSPF6_DEST_TYPE_RANGE)
	{
	  /* Whether the route have active longer prefix */
	  if (! CHECK_FLAG (route->flag, OSPF6_ROUTE_ACTIVE_SUMMARY))
	    {
	      if (is_debug)
		zlog_debug ("The range is not active. withdraw");

	      ospf6_abr_delete_route (route, summary, summary_table, old);
	    }
	}
      else
	if (old)
	  ospf6_lsa_purge (old);

      return 0;
    }

  if ((route->type == OSPF6_DEST_TYPE_ROUTER) && IS_AREA_STUB(area))
    {
      if (is_debug)
        zlog_debug ("Area has been stubbed, purge Inter-Router LSA");

      ospf6_abr_delete_route (route, summary, summary_table, old);
      return 0;
    }

  /* do not generate if the route cost is greater or equal to LSInfinity */
  if (route->path.cost >= OSPF_LS_INFINITY)
    {
      /* When we're clearing the range route because all active prefixes
       * under the range are gone, we set the range's cost to
       * OSPF_AREA_RANGE_COST_UNSPEC, which is > OSPF_LS_INFINITY. We
       * don't want to trigger the code here for that. This code is for
       * handling routes that have gone to infinity. The range removal happens
       * elsewhere.
       */
      if ((route->type != OSPF6_DEST_TYPE_RANGE) &&
	  (route->path.cost != OSPF_AREA_RANGE_COST_UNSPEC))
	{
	  if (is_debug)
	    zlog_debug ("The cost exceeds LSInfinity, withdraw");
	  if (old)
	    ospf6_lsa_purge (old);
	  return 0;
	}
    }

  /* if this is a route to ASBR */
  if (route->type == OSPF6_DEST_TYPE_ROUTER)
    {
      /* Only the prefered best path is considered */
      if (! CHECK_FLAG (route->flag, OSPF6_ROUTE_BEST))
        {
          if (is_debug)
            zlog_debug ("This is the secondary path to the ASBR, ignore");
	  ospf6_abr_delete_route (route, summary, summary_table, old);
          return 0;
        }

      /* Do not generate if the area is stub */
      /* XXX */
    }

  /* if this is an intra-area route, this may be suppressed by aggregation */
  if (route->type == OSPF6_DEST_TYPE_NETWORK &&
      route->path.type == OSPF6_PATH_TYPE_INTRA)
    {
      /* search for configured address range for the route's area */
      route_area = ospf6_area_lookup (route->path.area_id, area->ospf6);
      assert (route_area);
      range = ospf6_route_lookup_bestmatch (&route->prefix,
                                            route_area->range_table);

      /* ranges are ignored when originate backbone routes to transit area.
         Otherwise, if ranges are configured, the route is suppressed. */
      if (range && ! CHECK_FLAG (range->flag, OSPF6_ROUTE_REMOVE) &&
          (route->path.area_id != OSPF_AREA_BACKBONE ||
           ! IS_AREA_TRANSIT (area)))
        {
          if (is_debug)
            {
              prefix2str (&range->prefix, buf, sizeof (buf));
              zlog_debug ("Suppressed by range %s of area %s",
                         buf, route_area->name);
            }
	  ospf6_abr_delete_route (route, summary, summary_table, old);
          return 0;
        }
    }

  /* If this is a configured address range */
  if (route->type == OSPF6_DEST_TYPE_RANGE)
    {
      /* If DoNotAdvertise is set */
      if (CHECK_FLAG (route->flag, OSPF6_ROUTE_DO_NOT_ADVERTISE))
        {
          if (is_debug)
            zlog_debug ("This is the range with DoNotAdvertise set. ignore");
	  ospf6_abr_delete_route (route, summary, summary_table, old);
	  return 0;
        }

      /* If there are no active prefixes in this range, remove */
      if (! CHECK_FLAG (route->flag, OSPF6_ROUTE_ACTIVE_SUMMARY))
        {
          if (is_debug)
            zlog_debug ("The range is not active. withdraw");
	  ospf6_abr_delete_route (route, summary, summary_table, old);
          return 0;
        }
    }

  /* Check export list */
  if (EXPORT_NAME (area))
    {
      if (EXPORT_LIST (area) == NULL)
        EXPORT_LIST (area) =
          access_list_lookup (AFI_IP6, EXPORT_NAME (area));

      if (EXPORT_LIST (area))
        if (access_list_apply (EXPORT_LIST (area),
                               &route->prefix) == FILTER_DENY)
          {
            if (is_debug)
              {
                inet_ntop (AF_INET, &(ADV_ROUTER_IN_PREFIX (&route->prefix)),
                           buf, sizeof(buf));
                zlog_debug ("prefix %s was denied by export list", buf);
              }
            return 0;
          }
    }

  /* Check filter-list */
  if (PREFIX_NAME_OUT (area))
    {
      if (PREFIX_LIST_OUT (area) == NULL)
        PREFIX_LIST_OUT (area) =
          prefix_list_lookup(AFI_IP6, PREFIX_NAME_OUT (area));

      if (PREFIX_LIST_OUT (area))
         if (prefix_list_apply (PREFIX_LIST_OUT (area), 
                                &route->prefix) != PREFIX_PERMIT) 
           {
             if (is_debug)
               {
                 inet_ntop (AF_INET, &(ADV_ROUTER_IN_PREFIX (&route->prefix)),
                            buf, sizeof (buf));
                 zlog_debug ("prefix %s was denied by filter-list out", buf);
               }
             return 0;
           }
    }

  /* the route is going to be originated. store it in area's summary_table */
  if (summary == NULL)
    {
      summary = ospf6_route_copy (route);
      summary->path.origin.adv_router = area->ospf6->router_id;

      if (route->type == OSPF6_DEST_TYPE_ROUTER)
	{
	  summary->path.origin.type = htons (OSPF6_LSTYPE_INTER_ROUTER);
	  summary->path.origin.id = ADV_ROUTER_IN_PREFIX (&route->prefix);
	}
      else
	{
	  summary->path.origin.type = htons (OSPF6_LSTYPE_INTER_PREFIX);
	  if (route->type == OSPF6_DEST_TYPE_RANGE)
	    summary->path.origin.id  = route->linkstate_id;
	  else
	    summary->path.origin.id =
	      ospf6_new_ls_id (summary->path.origin.type,
			       summary->path.origin.adv_router, area->lsdb);
	}
      summary = ospf6_route_add (summary, summary_table);

    }
  else
    {
      summary->type = route->type;
      quagga_gettime (QUAGGA_CLK_MONOTONIC, &summary->changed);
    }

  summary->path.router_bits = route->path.router_bits;
  summary->path.options[0] = route->path.options[0];
  summary->path.options[1] = route->path.options[1];
  summary->path.options[2] = route->path.options[2];
  summary->path.prefix_options = route->path.prefix_options;
  summary->path.area_id = area->area_id;
  summary->path.type = OSPF6_PATH_TYPE_INTER;
  summary->path.cost = route->path.cost;
    /* summary->nexthop[0] = route->nexthop[0]; */

  /* prepare buffer */
  memset (buffer, 0, sizeof (buffer));
  lsa_header = (struct ospf6_lsa_header *) buffer;

  if (route->type == OSPF6_DEST_TYPE_ROUTER)
    {
      router_lsa = (struct ospf6_inter_router_lsa *)
        ((caddr_t) lsa_header + sizeof (struct ospf6_lsa_header));
      p = (caddr_t) router_lsa + sizeof (struct ospf6_inter_router_lsa);

      /* Fill Inter-Area-Router-LSA */
      router_lsa->options[0] = route->path.options[0];
      router_lsa->options[1] = route->path.options[1];
      router_lsa->options[2] = route->path.options[2];
      OSPF6_ABR_SUMMARY_METRIC_SET (router_lsa, route->path.cost);
      router_lsa->router_id = ADV_ROUTER_IN_PREFIX (&route->prefix);
      type = htons (OSPF6_LSTYPE_INTER_ROUTER);
    }
  else
    {
      prefix_lsa = (struct ospf6_inter_prefix_lsa *)
        ((caddr_t) lsa_header + sizeof (struct ospf6_lsa_header));
      p = (caddr_t) prefix_lsa + sizeof (struct ospf6_inter_prefix_lsa);

      /* Fill Inter-Area-Prefix-LSA */
      OSPF6_ABR_SUMMARY_METRIC_SET (prefix_lsa, route->path.cost);
      prefix_lsa->prefix.prefix_length = route->prefix.prefixlen;
      prefix_lsa->prefix.prefix_options = route->path.prefix_options;

      /* set Prefix */
      memcpy (p, &route->prefix.u.prefix6,
              OSPF6_PREFIX_SPACE (route->prefix.prefixlen));
      ospf6_prefix_apply_mask (&prefix_lsa->prefix);
      p += OSPF6_PREFIX_SPACE (route->prefix.prefixlen);
      type = htons (OSPF6_LSTYPE_INTER_PREFIX);
    }

  /* Fill LSA Header */
  lsa_header->age = 0;
  lsa_header->type = type;
  lsa_header->id = summary->path.origin.id;
  lsa_header->adv_router = area->ospf6->router_id;
  lsa_header->seqnum =
    ospf6_new_ls_seqnum (lsa_header->type, lsa_header->id,
                         lsa_header->adv_router, area->lsdb);
  lsa_header->length = htons ((caddr_t) p - (caddr_t) lsa_header);

  /* LSA checksum */
  ospf6_lsa_checksum (lsa_header);

  /* create LSA */
  lsa = ospf6_lsa_create (lsa_header);

  /* Originate */
  ospf6_lsa_originate_area (lsa, area);

  return 1;
}

void
ospf6_abr_range_update (struct ospf6_route *range)
{
  u_int32_t cost = 0;
  struct ospf6_route *ro;
  int gen_range_summary = 0;
  char buf[INET6_ADDRSTRLEN];

  assert (range->type == OSPF6_DEST_TYPE_RANGE);
  prefix2str (&range->prefix, buf, sizeof (buf));

  if (CHECK_FLAG(range->flag, OSPF6_ROUTE_REMOVE))
    {
      UNSET_FLAG (range->flag, OSPF6_ROUTE_ACTIVE_SUMMARY);
      gen_range_summary = 1;
    }
  else
    {
      /* update range's cost and active flag */
      for (ro = ospf6_route_match_head (&range->prefix, ospf6->route_table);
	   ro; ro = ospf6_route_match_next (&range->prefix, ro))
	{
	  if (ro->path.area_id == range->path.area_id &&
	      (ro->path.type == OSPF6_PATH_TYPE_INTRA) &&
	      ! CHECK_FLAG (ro->flag, OSPF6_ROUTE_REMOVE))
	    cost = MAX (cost, ro->path.cost);
	}
    }

  /* Non-zero cost is a proxy for active longer prefixes in this range.
   * If there are active routes covered by this range AND either the configured
   * cost has changed or the summarized cost has changed then redo summaries.
   * Alternately, if there are no longer active prefixes and there are
   * summary announcements, withdraw those announcements.
   *
   * The don't advertise code relies on the path.cost being set to UNSPEC to
   * work the first time. Subsequent times the path.cost is not 0 anyway if there
   * were active ranges.
   */
  if (CHECK_FLAG (range->flag, OSPF6_ROUTE_DO_NOT_ADVERTISE))
    {
      if (range->path.cost != 0)
	{
	  range->path.cost = 0;
	  gen_range_summary = 1;
	}
    }
  else if (cost &&
	   (((range->path.u.cost_config != OSPF_AREA_RANGE_COST_UNSPEC) &&
	     (range->path.cost != range->path.u.cost_config)) ||
	    ((range->path.u.cost_config == OSPF_AREA_RANGE_COST_UNSPEC) &&
	     (range->path.cost != cost))))
    {
      if (range->path.u.cost_config == OSPF_AREA_RANGE_COST_UNSPEC)
	{
	  range->path.cost = cost;
	}
      else
	{
	  range->path.cost = range->path.u.cost_config;
	}

      SET_FLAG (range->flag, OSPF6_ROUTE_ACTIVE_SUMMARY);
      gen_range_summary = 1;
    }
  else if (!cost && CHECK_FLAG (range->flag, OSPF6_ROUTE_ACTIVE_SUMMARY))
    {
      UNSET_FLAG (range->flag, OSPF6_ROUTE_ACTIVE_SUMMARY);
      range->path.cost = OSPF_AREA_RANGE_COST_UNSPEC;
      gen_range_summary = 1;
    }

  if (gen_range_summary)
    {
      ospf6_abr_originate_summary (range);

      if (CHECK_FLAG (range->flag, OSPF6_ROUTE_ACTIVE_SUMMARY))
	{
	  if (IS_OSPF6_DEBUG_ABR)
	    zlog_debug ("Add discard route");

	  ospf6_zebra_add_discard (range);
	}
      else
	{
	  if (IS_OSPF6_DEBUG_ABR)
	    zlog_debug ("Delete discard route");

	  ospf6_zebra_delete_discard (range);
	}
    }
}

void
ospf6_abr_originate_summary (struct ospf6_route *route)
{
  struct listnode *node, *nnode;
  struct ospf6_area *oa;
  struct ospf6_route *range = NULL;

  if (route->type == OSPF6_DEST_TYPE_NETWORK)
    {
      oa = ospf6_area_lookup (route->path.area_id, ospf6);
      range = ospf6_route_lookup_bestmatch (&route->prefix, oa->range_table);
      if (range)
	{
	  ospf6_abr_range_update (range);
	}
    }

  for (ALL_LIST_ELEMENTS (ospf6->area_list, node, nnode, oa))
    ospf6_abr_originate_summary_to_area (route, oa);
}

/* RFC 2328 16.2. Calculating the inter-area routes */
void
ospf6_abr_examin_summary (struct ospf6_lsa *lsa, struct ospf6_area *oa)
{
  struct prefix prefix, abr_prefix;
  struct ospf6_route_table *table = NULL;
  struct ospf6_route *range, *route, *old = NULL;
  struct ospf6_route *abr_entry;
  u_char type = 0;
  char options[3] = {0, 0, 0};
  u_int8_t prefix_options = 0;
  u_int32_t cost = 0;
  u_char router_bits = 0;
  char buf[64];
  int is_debug = 0;
  struct ospf6_inter_prefix_lsa *prefix_lsa = NULL;
  struct ospf6_inter_router_lsa *router_lsa = NULL;

  memset (&prefix, 0, sizeof (prefix));

  if (lsa->header->type == htons (OSPF6_LSTYPE_INTER_PREFIX))
    {
      if (IS_OSPF6_DEBUG_EXAMIN (INTER_PREFIX))
        {
          is_debug++;
          zlog_debug ("Examin %s in area %s", lsa->name, oa->name);
        }

      prefix_lsa = (struct ospf6_inter_prefix_lsa *)
        OSPF6_LSA_HEADER_END (lsa->header);
      prefix.family = AF_INET6;
      prefix.prefixlen = prefix_lsa->prefix.prefix_length;
      ospf6_prefix_in6_addr (&prefix.u.prefix6, &prefix_lsa->prefix);
      if (is_debug)
        prefix2str (&prefix, buf, sizeof (buf));
      table = oa->ospf6->route_table;
      type = OSPF6_DEST_TYPE_NETWORK;
      prefix_options = prefix_lsa->prefix.prefix_options;
      cost = OSPF6_ABR_SUMMARY_METRIC (prefix_lsa);
    }
  else if (lsa->header->type == htons (OSPF6_LSTYPE_INTER_ROUTER))
    {
      if (IS_OSPF6_DEBUG_EXAMIN (INTER_ROUTER))
        {
          is_debug++;
          zlog_debug ("Examin %s in area %s", lsa->name, oa->name);
        }

      router_lsa = (struct ospf6_inter_router_lsa *)
        OSPF6_LSA_HEADER_END (lsa->header);
      ospf6_linkstate_prefix (router_lsa->router_id, htonl (0), &prefix);
      if (is_debug)
        inet_ntop (AF_INET, &router_lsa->router_id, buf, sizeof (buf));

      table = oa->ospf6->brouter_table;
      type = OSPF6_DEST_TYPE_ROUTER;
      options[0] = router_lsa->options[0];
      options[1] = router_lsa->options[1];
      options[2] = router_lsa->options[2];
      cost = OSPF6_ABR_SUMMARY_METRIC (router_lsa);
      SET_FLAG (router_bits, OSPF6_ROUTER_BIT_E);
    }
  else
    assert (0);

  /* Find existing route */
  route = ospf6_route_lookup (&prefix, table);
  if (route)
    ospf6_route_lock (route);
  while (route && ospf6_route_is_prefix (&prefix, route))
    {
      if (route->path.area_id == oa->area_id &&
          route->path.origin.type == lsa->header->type &&
          route->path.origin.id == lsa->header->id &&
          route->path.origin.adv_router == lsa->header->adv_router &&
          ! CHECK_FLAG (route->flag, OSPF6_ROUTE_WAS_REMOVED))
        old = route;
      route = ospf6_route_next (route);
    }
  if (route)
    ospf6_route_unlock (route);

  /* (1) if cost == LSInfinity or if the LSA is MaxAge */
  if (cost == OSPF_LS_INFINITY)
    {
      if (is_debug)
        zlog_debug ("cost is LS_INFINITY, ignore");
      if (old)
        ospf6_route_remove (old, table);
      return;
    }
  if (OSPF6_LSA_IS_MAXAGE (lsa))
    {
      if (is_debug)
        zlog_debug ("LSA is MaxAge, ignore");
      if (old)
        ospf6_route_remove (old, table);
      return;
    }

  /* (2) if the LSA is self-originated, ignore */
  if (lsa->header->adv_router == oa->ospf6->router_id)
    {
      if (is_debug)
        zlog_debug ("LSA is self-originated, ignore");
      if (old)
        ospf6_route_remove (old, table);
      return;
    }

  /* (3) if the prefix is equal to an active configured address range */
  /*     or if the NU bit is set in the prefix */
  if (lsa->header->type == htons (OSPF6_LSTYPE_INTER_PREFIX))
    {
      range = ospf6_route_lookup (&prefix, oa->range_table);
      if (range)
        {
          if (is_debug)
            zlog_debug ("Prefix is equal to address range, ignore");
          if (old)
            ospf6_route_remove (old, table);
          return;
        }

      if (CHECK_FLAG (prefix_lsa->prefix.prefix_options,
		      OSPF6_PREFIX_OPTION_NU) ||
	  CHECK_FLAG (prefix_lsa->prefix.prefix_options,
		      OSPF6_PREFIX_OPTION_LA))
	{
          if (is_debug)
            zlog_debug ("Prefix has NU/LA bit set, ignore");
          if (old)
            ospf6_route_remove (old, table);
          return;
	}
    }

  if (lsa->header->type == htons (OSPF6_LSTYPE_INTER_ROUTER))
    {
      /* To pass test suites */
      if (! OSPF6_OPT_ISSET (router_lsa->options, OSPF6_OPT_R) ||
	  ! OSPF6_OPT_ISSET (router_lsa->options, OSPF6_OPT_V6))
	{
          if (is_debug)
            zlog_debug ("Prefix has NU/LA bit set, ignore");
          if (old)
            ospf6_route_remove (old, table);

          return;
	}
      /* Avoid infinite recursion if someone has maliciously announced an
	 Inter-Router LSA for an ABR
      */
      if (lsa->header->adv_router == router_lsa->router_id)
	{
	  if (is_debug)
	    zlog_debug ("Ignorning Inter-Router LSA for an ABR (%s)",
			buf);
	  if (old)
	    ospf6_route_remove (old, table);

	  return;
	}
    }

  /* (4) if the routing table entry for the ABR does not exist */
  ospf6_linkstate_prefix (lsa->header->adv_router, htonl (0), &abr_prefix);
  abr_entry = ospf6_route_lookup (&abr_prefix, oa->ospf6->brouter_table);
  if (abr_entry == NULL || abr_entry->path.area_id != oa->area_id ||
      CHECK_FLAG (abr_entry->flag, OSPF6_ROUTE_REMOVE) ||
      ! CHECK_FLAG (abr_entry->path.router_bits, OSPF6_ROUTER_BIT_B))
    {
      if (is_debug)
        zlog_debug ("ABR router entry does not exist, ignore");
      if (old)
        ospf6_route_remove (old, table);
      return;
    }

  /* Check import list */
  if (IMPORT_NAME (oa))
    {
      if (IMPORT_LIST (oa) == NULL)
        IMPORT_LIST (oa) = access_list_lookup (AFI_IP6, IMPORT_NAME (oa));

      if (IMPORT_LIST (oa))
        if (access_list_apply (IMPORT_LIST (oa), &prefix) == FILTER_DENY)
          {
            if (is_debug)
              zlog_debug ("Prefix was denied by import-list");
            if (old)
              ospf6_route_remove (old, table);
            return;
          }
    }

  /* Check input prefix-list */
  if (PREFIX_NAME_IN (oa))
    {
      if (PREFIX_LIST_IN (oa) == NULL)
        PREFIX_LIST_IN (oa) = prefix_list_lookup (AFI_IP6, PREFIX_NAME_IN (oa));

      if (PREFIX_LIST_IN (oa))
        if (prefix_list_apply (PREFIX_LIST_IN (oa), &prefix) != PREFIX_PERMIT)
          {
            if (is_debug)
              zlog_debug ("Prefix was denied by prefix-list");
            if (old)
              ospf6_route_remove (old, table);
            return;
          }
    }

  /* (5),(6): the path preference is handled by the sorting
     in the routing table. Always install the path by substituting
     old route (if any). */
  if (old)
    route = ospf6_route_copy (old);
  else
    route = ospf6_route_create ();

  route->type = type;
  route->prefix = prefix;
  route->path.origin.type = lsa->header->type;
  route->path.origin.id = lsa->header->id;
  route->path.origin.adv_router = lsa->header->adv_router;
  route->path.router_bits = router_bits;
  route->path.options[0] = options[0];
  route->path.options[1] = options[1];
  route->path.options[2] = options[2];
  route->path.prefix_options = prefix_options;
  route->path.area_id = oa->area_id;
  route->path.type = OSPF6_PATH_TYPE_INTER;
  route->path.cost = abr_entry->path.cost + cost;

  ospf6_route_copy_nexthops (route, abr_entry);

  /* (7) If the routes are identical, copy the next hops over to existing
     route. ospf6's route table implementation will otherwise string both
     routes, but keep the older one as the best route since the routes
     are identical.
  */
  old = ospf6_route_lookup (&prefix, table);

  if (old && (ospf6_route_cmp (route, old) == 0))
    {
      ospf6_route_merge_nexthops (old, route);
      /* Update RIB/FIB */
      if (table->hook_add)
	(*table->hook_add) (old);

      /* Delete new route */
      ospf6_route_delete (route);
    }
  else
    {
      if (is_debug)
	zlog_debug ("Install route: %s", buf);
      /* ospf6_ia_add_nw_route (table, &prefix, route); */
      ospf6_route_add (route, table);
    }
}

void
ospf6_abr_examin_brouter (u_int32_t router_id)
{
  struct ospf6_lsa *lsa;
  struct ospf6_area *oa;
  u_int16_t type;

  if (ospf6_is_router_abr (ospf6))
    oa = ospf6->backbone;
  else
    oa = listgetdata(listhead(ospf6->area_list));

  type = htons (OSPF6_LSTYPE_INTER_ROUTER);
  for (lsa = ospf6_lsdb_type_router_head (type, router_id, oa->lsdb); lsa;
       lsa = ospf6_lsdb_type_router_next (type, router_id, lsa))
      ospf6_abr_examin_summary (lsa, oa);

  type = htons (OSPF6_LSTYPE_INTER_PREFIX);
  for (lsa = ospf6_lsdb_type_router_head (type, router_id, oa->lsdb); lsa;
       lsa = ospf6_lsdb_type_router_next (type, router_id, lsa))
    ospf6_abr_examin_summary (lsa, oa);
}

void
ospf6_abr_reimport (struct ospf6_area *oa)
{
  struct ospf6_lsa *lsa;
  u_int16_t type;

  type = htons (OSPF6_LSTYPE_INTER_ROUTER);
  for (lsa = ospf6_lsdb_type_head (type, oa->lsdb); lsa;
       lsa = ospf6_lsdb_type_next (type, lsa))
    ospf6_abr_examin_summary (lsa, oa);

  type = htons (OSPF6_LSTYPE_INTER_PREFIX);
  for (lsa = ospf6_lsdb_type_head (type, oa->lsdb); lsa;
       lsa = ospf6_lsdb_type_next (type, lsa))
    ospf6_abr_examin_summary (lsa, oa);
}



/* Display functions */
static char *
ospf6_inter_area_prefix_lsa_get_prefix_str (struct ospf6_lsa *lsa, char *buf,
					    int buflen, int pos)
{
  struct ospf6_inter_prefix_lsa *prefix_lsa;
  struct in6_addr in6;

  if (lsa != NULL)
    {
      prefix_lsa = (struct ospf6_inter_prefix_lsa *)
	OSPF6_LSA_HEADER_END (lsa->header);

      ospf6_prefix_in6_addr (&in6, &prefix_lsa->prefix);
      if (buf)
	{
	  inet_ntop (AF_INET6, &in6, buf, buflen);
	  sprintf (&buf[strlen(buf)], "/%d", prefix_lsa->prefix.prefix_length);
	}
    }

  return (buf);
}

static int
ospf6_inter_area_prefix_lsa_show (struct vty *vty, struct ospf6_lsa *lsa)
{
  struct ospf6_inter_prefix_lsa *prefix_lsa;
  char buf[INET6_ADDRSTRLEN];

  prefix_lsa = (struct ospf6_inter_prefix_lsa *)
    OSPF6_LSA_HEADER_END (lsa->header);

  vty_out (vty, "     Metric: %lu%s",
           (u_long) OSPF6_ABR_SUMMARY_METRIC (prefix_lsa), VNL);

  ospf6_prefix_options_printbuf (prefix_lsa->prefix.prefix_options,
                                 buf, sizeof (buf));
  vty_out (vty, "     Prefix Options: %s%s", buf, VNL);

  vty_out (vty, "     Prefix: %s%s",
	   ospf6_inter_area_prefix_lsa_get_prefix_str (lsa, buf, sizeof(buf),
						       0), VNL);

  return 0;
}

static char *
ospf6_inter_area_router_lsa_get_prefix_str (struct ospf6_lsa *lsa, char *buf,
					    int buflen, int pos)
{
  struct ospf6_inter_router_lsa *router_lsa;

  if (lsa != NULL)
    {
      router_lsa = (struct ospf6_inter_router_lsa *)
	OSPF6_LSA_HEADER_END (lsa->header);


      if (buf)
	inet_ntop (AF_INET, &router_lsa->router_id, buf, buflen);
    }

  return (buf);
}

static int
ospf6_inter_area_router_lsa_show (struct vty *vty, struct ospf6_lsa *lsa)
{
  struct ospf6_inter_router_lsa *router_lsa;
  char buf[64];

  router_lsa = (struct ospf6_inter_router_lsa *)
    OSPF6_LSA_HEADER_END (lsa->header);

  ospf6_options_printbuf (router_lsa->options, buf, sizeof (buf));
  vty_out (vty, "     Options: %s%s", buf, VNL);
  vty_out (vty, "     Metric: %lu%s",
           (u_long) OSPF6_ABR_SUMMARY_METRIC (router_lsa), VNL);

  inet_ntop (AF_INET, &router_lsa->router_id, buf, sizeof (buf));
  vty_out (vty, "     Destination Router ID: %s%s", buf, VNL);

  return 0;
}

/* Debug commands */
DEFUN (debug_ospf6_abr,
       debug_ospf6_abr_cmd,
       "debug ospf6 abr",
       DEBUG_STR
       OSPF6_STR
       "Debug OSPFv3 ABR function\n"
      )
{
  OSPF6_DEBUG_ABR_ON ();
  return CMD_SUCCESS;
}

DEFUN (no_debug_ospf6_abr,
       no_debug_ospf6_abr_cmd,
       "no debug ospf6 abr",
       NO_STR
       DEBUG_STR
       OSPF6_STR
       "Debug OSPFv3 ABR function\n"
      )
{
  OSPF6_DEBUG_ABR_OFF ();
  return CMD_SUCCESS;
}

int
config_write_ospf6_debug_abr (struct vty *vty)
{
  if (IS_OSPF6_DEBUG_ABR)
    vty_out (vty, "debug ospf6 abr%s", VNL);
  return 0;
}

void
install_element_ospf6_debug_abr (void)
{
  install_element (ENABLE_NODE, &debug_ospf6_abr_cmd);
  install_element (ENABLE_NODE, &no_debug_ospf6_abr_cmd);
  install_element (CONFIG_NODE, &debug_ospf6_abr_cmd);
  install_element (CONFIG_NODE, &no_debug_ospf6_abr_cmd);
}

struct ospf6_lsa_handler inter_prefix_handler =
{
  OSPF6_LSTYPE_INTER_PREFIX,
  "Inter-Prefix",
  "IAP",
  ospf6_inter_area_prefix_lsa_show,
  ospf6_inter_area_prefix_lsa_get_prefix_str,
};

struct ospf6_lsa_handler inter_router_handler =
{
  OSPF6_LSTYPE_INTER_ROUTER,
  "Inter-Router",
  "IAR",
  ospf6_inter_area_router_lsa_show,
  ospf6_inter_area_router_lsa_get_prefix_str,
};

void
ospf6_abr_init (void)
{
  ospf6_install_lsa_handler (&inter_prefix_handler);
  ospf6_install_lsa_handler (&inter_router_handler);
}