ospf6_abr.c

linux 路由软件 可支持RIP OSPF BGP等

/*
 * 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 "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_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)
{
  listnode node;
  struct ospf6_area *oa;
  int area_count = 0;

  for (node = listhead (o->area_list); node; nextnode (node))
    {
      oa = OSPF6_AREA (getdata (node));
      if (IS_AREA_ENABLED (oa))
        area_count++;
    }

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

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

  for (node = listhead (area->ospf6->area_list); node; nextnode (node))
    {
      oa = OSPF6_AREA (getdata (node));

      /* 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;
  listnode node;

  /* 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 (node = listhead (area->ospf6->area_list); node; nextnode (node))
    {
      oa = OSPF6_AREA (getdata (node));

      /* update B bit for each area */
      OSPF6_ROUTER_LSA_SCHEDULE (oa);
    }
}

/* RFC 2328 12.4.3. Summary-LSAs */
void
ospf6_abr_originate_summary_to_area (struct ospf6_route *route,
                                     struct ospf6_area *area)
{
  struct ospf6_lsa *lsa, *old = NULL;
  struct ospf6_interface *oi;
  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;

  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_info ("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_info ("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_info ("The route has just removed, purge previous LSA");
      if (summary)
        ospf6_route_remove (summary, summary_table);
      if (old)
        ospf6_lsa_purge (old);
      return;
    }

  /* 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_info ("Route type is none of network, range nor ASBR, withdraw");
      if (summary)
        ospf6_route_remove (summary, summary_table);
      if (old)
        ospf6_lsa_purge (old);
      return;
    }

  /* 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_info ("Path type is external, withdraw");
      if (summary)
        ospf6_route_remove (summary, summary_table);
      if (old)
        ospf6_lsa_purge (old);
      return;
    }

  /* 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_info ("The route is in the area itself, ignore");
      if (summary)
        ospf6_route_remove (summary, summary_table);
      if (old)
        ospf6_lsa_purge (old);
      return;
    }

  /* do not generate if the nexthops belongs to the target area */
  oi = ospf6_interface_lookup_by_ifindex (route->nexthop[0].ifindex);
  if (oi && oi->area && oi->area == area)
    {
      if (is_debug)
        zlog_info ("The route's nexthop is in the same area, ignore");
      if (summary)
        ospf6_route_remove (summary, summary_table);
      if (old)
        ospf6_lsa_purge (old);
      return;
    }

  /* do not generate if the route cost is greater or equal to LSInfinity */
  if (route->path.cost >= LS_INFINITY)
    {
      if (is_debug)
        zlog_info ("The cost exceeds LSInfinity, withdraw");
      if (summary)
        ospf6_route_remove (summary, summary_table);
      if (old)
        ospf6_lsa_purge (old);
      return;
    }

  /* 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_info ("This is the secondary path to the ASBR, ignore");
          if (summary)
            ospf6_route_remove (summary, summary_table);
          if (old)
            ospf6_lsa_purge (old);
          return;
        }

      /* 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 != BACKBONE_AREA_ID ||
           ! IS_AREA_TRANSIT (area)))
        {
          if (is_debug)
            {
              prefix2str (&range->prefix, buf, sizeof (buf));
              zlog_info ("Suppressed by range %s of area %s",
                         buf, route_area->name);
            }

          if (summary)
            ospf6_route_remove (summary, summary_table);
          if (old)
            ospf6_lsa_purge (old);
          return;
        }
    }

  /* 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_info ("This is the range with DoNotAdvertise set. ignore");
          if (summary)
            ospf6_route_remove (summary, summary_table);
          if (old)
            ospf6_lsa_purge (old);
          return;
        }

      /* Whether the route have active longer prefix */
      if (! CHECK_FLAG (route->flag, OSPF6_ROUTE_ACTIVE_SUMMARY))
        {
          if (is_debug)
            zlog_info ("The range is not active. withdraw");
          if (summary)
            ospf6_route_remove (summary, summary_table);
          if (old)
            ospf6_lsa_purge (old);
          return;
        }
    }

  /* the route is going to be originated. store it in area's summary_table */
  if (summary == NULL)
    {
      summary = ospf6_route_copy (route);
      if (route->type == OSPF6_DEST_TYPE_NETWORK ||
          route->type == OSPF6_DEST_TYPE_RANGE)
        summary->path.origin.type = htons (OSPF6_LSTYPE_INTER_PREFIX);
      else
        summary->path.origin.type = htons (OSPF6_LSTYPE_INTER_ROUTER);
      summary->path.origin.adv_router = area->ospf6->router_id;
      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;
      gettimeofday (&summary->changed, NULL);
    }

  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];