bgpd.c

大名鼎鼎的路由器源码。程序分ZEBRA、OSPFRIP等3个包。程序框架采用一个路由协议一个进程的方式

/* BGP-4, BGP-4+ daemon program
   Copyright (C) 1996, 97, 98, 99, 2000 Kunihiro Ishiguro

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 "prefix.h"
#include "thread.h"
#include "buffer.h"
#include "stream.h"
#include "command.h"
#include "sockunion.h"
#include "network.h"
#include "memory.h"
#include "filter.h"
#include "routemap.h"
#include "str.h"
#include "log.h"
#include "plist.h"
#include "linklist.h"

#include "bgpd/bgpd.h"
#include "bgpd/bgp_table.h"
#include "bgpd/bgp_aspath.h"
#include "bgpd/bgp_route.h"
#include "bgpd/bgp_dump.h"
#include "bgpd/bgp_debug.h"
#include "bgpd/bgp_community.h"
#include "bgpd/bgp_attr.h"
#include "bgpd/bgp_regex.h"
#include "bgpd/bgp_clist.h"
#include "bgpd/bgp_fsm.h"
#include "bgpd/bgp_packet.h"
#include "bgpd/bgp_zebra.h"
#include "bgpd/bgp_open.h"
#include "bgpd/bgp_filter.h"
#include "bgpd/bgp_nexthop.h"
#include "bgpd/bgp_damp.h"
#include "bgpd/bgp_mplsvpn.h"
#include "bgpd/bgp_advertise.h"
#include "bgpd/bgp_network.h"
#include "bgpd/bgp_vty.h"
#ifdef HAVE_SNMP
#include "bgpd/bgp_snmp.h"
#endif /* HAVE_SNMP */

/* BGP process wide configuration.  */
static struct bgp_master bgp_master;

/* BGP process wide configuration pointer to export.  */
struct bgp_master *bm;

/* BGP community-list.  */
struct community_list_handler *bgp_clist;

/* BGP global flag manipulation.  */
int
bgp_option_set (int flag)
{
  switch (flag)
    {
    case BGP_OPT_NO_FIB:
    case BGP_OPT_MULTIPLE_INSTANCE:
    case BGP_OPT_CONFIG_CISCO:
      SET_FLAG (bm->options, flag);
      break;
    default:
      return BGP_ERR_INVALID_FLAG;
      break;
    }
  return 0;
}

int
bgp_option_unset (int flag)
{
  switch (flag)
    {
    case BGP_OPT_MULTIPLE_INSTANCE:
      if (listcount (bm->bgp) > 1)
	return BGP_ERR_MULTIPLE_INSTANCE_USED;
      /* Fall through.  */
    case BGP_OPT_NO_FIB:
    case BGP_OPT_CONFIG_CISCO:
      UNSET_FLAG (bm->options, flag);
      break;
    default:
      return BGP_ERR_INVALID_FLAG;
      break;
    }
  return 0;
}

int
bgp_option_check (int flag)
{
  return CHECK_FLAG (bm->options, flag);
}

/* BGP flag manipulation.  */
int
bgp_flag_set (struct bgp *bgp, int flag)
{
  SET_FLAG (bgp->flags, flag);
  return 0;
}

int
bgp_flag_unset (struct bgp *bgp, int flag)
{
  UNSET_FLAG (bgp->flags, flag);
  return 0;
}

int
bgp_flag_check (struct bgp *bgp, int flag)
{
  return CHECK_FLAG (bgp->flags, flag);
}

/* Internal function to set BGP structure configureation flag.  */
static void
bgp_config_set (struct bgp *bgp, int config)
{
  SET_FLAG (bgp->config, config);
}

static void
bgp_config_unset (struct bgp *bgp, int config)
{
  UNSET_FLAG (bgp->config, config);
}

static int
bgp_config_check (struct bgp *bgp, int config)
{
  return CHECK_FLAG (bgp->config, config);
}

/* Set BGP router identifier. */
int
bgp_router_id_set (struct bgp *bgp, struct in_addr *id)
{
  struct peer *peer;
  struct listnode *nn;

  if (bgp_config_check (bgp, BGP_CONFIG_ROUTER_ID)
      && IPV4_ADDR_SAME (&bgp->router_id, id))
    return 0;

  IPV4_ADDR_COPY (&bgp->router_id, id);
  bgp_config_set (bgp, BGP_CONFIG_ROUTER_ID);

  /* Set all peer's local identifier with this value. */
  LIST_LOOP (bgp->peer, peer, nn)
    {
      IPV4_ADDR_COPY (&peer->local_id, id);

      if (peer->status == Established)
	{
	  peer->last_reset = PEER_DOWN_RID_CHANGE;
	  bgp_notify_send (peer, BGP_NOTIFY_CEASE,
			   BGP_NOTIFY_CEASE_CONFIG_CHANGE);
	}
    }
  return 0;
}

/* Unset BGP router identifier. */
int
bgp_router_id_unset (struct bgp *bgp)
{
  struct peer *peer;
  struct listnode *nn;

  if (! bgp_config_check (bgp, BGP_CONFIG_ROUTER_ID))
    return 0;

  bgp->router_id.s_addr = 0;
  bgp_config_unset (bgp, BGP_CONFIG_ROUTER_ID);

  /* Clear peer router id configuration.  */
  LIST_LOOP (bgp->peer, peer, nn)
    {
      peer->local_id.s_addr = 0;
    }

  /* Set router-id from interface's address. */
  bgp_if_update_all ();

  /* Reset all BGP sessions to use new router-id.  */
  LIST_LOOP (bgp->peer, peer, nn)
    {
      if (peer->status == Established)
	{
	  peer->last_reset = PEER_DOWN_RID_CHANGE;
	  bgp_notify_send (peer, BGP_NOTIFY_CEASE,
			   BGP_NOTIFY_CEASE_CONFIG_CHANGE);
	}
    }

  return 0;
}

/* BGP's cluster-id control. */
int
bgp_cluster_id_set (struct bgp *bgp, struct in_addr *cluster_id)
{
  struct peer *peer;
  struct listnode *nn;

  if (bgp_config_check (bgp, BGP_CONFIG_CLUSTER_ID)
      && IPV4_ADDR_SAME (&bgp->cluster_id, cluster_id))
    return 0;

  IPV4_ADDR_COPY (&bgp->cluster_id, cluster_id);
  bgp_config_set (bgp, BGP_CONFIG_CLUSTER_ID);

  /* Clear all IBGP peer. */
  LIST_LOOP (bgp->peer, peer, nn)
    {
      if (peer_sort (peer) != BGP_PEER_IBGP)
	continue;

      if (peer->status == Established)
	{
	  peer->last_reset = PEER_DOWN_CLID_CHANGE;
	  bgp_notify_send (peer, BGP_NOTIFY_CEASE,
			   BGP_NOTIFY_CEASE_CONFIG_CHANGE);
	}
    }
  return 0;
}

int
bgp_cluster_id_unset (struct bgp *bgp)
{
  struct peer *peer;
  struct listnode *nn;

  if (! bgp_config_check (bgp, BGP_CONFIG_CLUSTER_ID))
    return 0;

  bgp->cluster_id.s_addr = 0;
  bgp_config_unset (bgp, BGP_CONFIG_CLUSTER_ID);

  /* Clear all IBGP peer. */
  LIST_LOOP (bgp->peer, peer, nn)
    {
      if (peer_sort (peer) != BGP_PEER_IBGP)
	continue;

      if (peer->status == Established)
	{
	  peer->last_reset = PEER_DOWN_CLID_CHANGE;
	  bgp_notify_send (peer, BGP_NOTIFY_CEASE,
			   BGP_NOTIFY_CEASE_CONFIG_CHANGE);
	}
    }
  return 0;
}

/* BGP timer configuration.  */
int
bgp_timers_set (struct bgp *bgp, u_int32_t keepalive, u_int32_t holdtime)
{
  bgp->default_keepalive = (keepalive < holdtime / 3 
			    ? keepalive : holdtime / 3);
  bgp->default_holdtime = holdtime;

  return 0;
}

int
bgp_timers_unset (struct bgp *bgp)
{
  bgp->default_keepalive = BGP_DEFAULT_KEEPALIVE;
  bgp->default_holdtime = BGP_DEFAULT_HOLDTIME;

  return 0;
}

/* BGP confederation configuration.  */
int
bgp_confederation_id_set (struct bgp *bgp, as_t as)
{
  struct peer *peer;
  struct listnode *nn;
  int already_confed;

  if (as == 0)
    return BGP_ERR_INVALID_AS;

  /* Remember - were we doing confederation before? */
  already_confed = bgp_config_check (bgp, BGP_CONFIG_CONFEDERATION);
  bgp->confed_id = as;
  bgp_config_set (bgp, BGP_CONFIG_CONFEDERATION);

  /* If we were doing confederation already, this is just an external
     AS change.  Just Reset EBGP sessions, not CONFED sessions.  If we
     were not doing confederation before, reset all EBGP sessions.  */
  LIST_LOOP (bgp->peer, peer, nn)
    {
      /* We're looking for peers who's AS is not local or part of our
	 confederation.  */
      if (already_confed)
	{
	  if (peer_sort (peer) == BGP_PEER_EBGP)
	    {
	      peer->local_as = as;
	      if (peer->status == Established)
		{
		  peer->last_reset = PEER_DOWN_CONFED_ID_CHANGE;
		  bgp_notify_send (peer, BGP_NOTIFY_CEASE,
			       BGP_NOTIFY_CEASE_CONFIG_CHANGE);
		}
	      else
		BGP_EVENT_ADD (peer, BGP_Stop);
	    }
	}
      else
	{
	  /* Not doign confederation before, so reset every non-local
	     session */
	  if (peer_sort (peer) != BGP_PEER_IBGP)
	    {
	      /* Reset the local_as to be our EBGP one */
	      if (peer_sort (peer) == BGP_PEER_EBGP)
		peer->local_as = as;
	      if (peer->status == Established)
		{
		  peer->last_reset = PEER_DOWN_CONFED_ID_CHANGE;
		  bgp_notify_send (peer, BGP_NOTIFY_CEASE,
			       BGP_NOTIFY_CEASE_CONFIG_CHANGE);
		}
	      else
		BGP_EVENT_ADD (peer, BGP_Stop);
	    }
	}
    }
  return 0;
}

int
bgp_confederation_id_unset (struct bgp *bgp)
{
  struct peer *peer;
  struct listnode *nn;

  bgp->confed_id = 0;
  bgp_config_unset (bgp, BGP_CONFIG_CONFEDERATION);
      
  LIST_LOOP (bgp->peer, peer, nn)
    {
      /* We're looking for peers who's AS is not local */
      if (peer_sort (peer) != BGP_PEER_IBGP)
	{
	  peer->local_as = bgp->as;
	  if (peer->status == Established)
	    {
	      peer->last_reset = PEER_DOWN_CONFED_ID_CHANGE;
	      bgp_notify_send (peer, BGP_NOTIFY_CEASE,
			       BGP_NOTIFY_CEASE_CONFIG_CHANGE);
	    }
	  else
	    BGP_EVENT_ADD (peer, BGP_Stop);
	}
    }
  return 0;
}

/* Is an AS part of the confed or not? */
int
bgp_confederation_peers_check (struct bgp *bgp, as_t as)
{
  int i;

  if (! bgp)
    return 0;

  for (i = 0; i < bgp->confed_peers_cnt; i++)
    if (bgp->confed_peers[i] == as)
      return 1;
  
  return 0;
}

/* Add an AS to the confederation set.  */
int
bgp_confederation_peers_add (struct bgp *bgp, as_t as)
{
  struct peer *peer;
  struct listnode *nn;

  if (! bgp)
    return BGP_ERR_INVALID_BGP;

  if (bgp->as == as)
    return BGP_ERR_INVALID_AS;

  if (bgp_confederation_peers_check (bgp, as))
    return -1;

  if (bgp->confed_peers)
    bgp->confed_peers = XREALLOC (MTYPE_BGP_CONFED_LIST, 
				  bgp->confed_peers,
				  (bgp->confed_peers_cnt + 1) * sizeof (as_t));
  else
    bgp->confed_peers = XMALLOC (MTYPE_BGP_CONFED_LIST, 
				 (bgp->confed_peers_cnt + 1) * sizeof (as_t));

  bgp->confed_peers[bgp->confed_peers_cnt] = as;
  bgp->confed_peers_cnt++;

  if (bgp_config_check (bgp, BGP_CONFIG_CONFEDERATION))
    {
      LIST_LOOP (bgp->peer, peer, nn)
	{
	  if (peer->as == as)
	    {
	      peer->local_as = bgp->as;
	      if (peer->status == Established)
		{
		  peer->last_reset = PEER_DOWN_CONFED_PEER_CHANGE;
		  bgp_notify_send (peer, BGP_NOTIFY_CEASE,
				   BGP_NOTIFY_CEASE_CONFIG_CHANGE);
		}
	      else
	        BGP_EVENT_ADD (peer, BGP_Stop);
	    }
	}
    }
  return 0;
}

/* Delete an AS from the confederation set.  */
int
bgp_confederation_peers_remove (struct bgp *bgp, as_t as)
{
  int i;
  int j;
  struct peer *peer;
  struct listnode *nn;

  if (! bgp)
    return -1;

  if (! bgp_confederation_peers_check (bgp, as))
    return -1;

  for (i = 0; i < bgp->confed_peers_cnt; i++)
    if (bgp->confed_peers[i] == as)
      for(j = i + 1; j < bgp->confed_peers_cnt; j++)
	bgp->confed_peers[j - 1] = bgp->confed_peers[j];

  bgp->confed_peers_cnt--;

  if (bgp->confed_peers_cnt == 0)
    {
      if (bgp->confed_peers)
	XFREE (MTYPE_BGP_CONFED_LIST, bgp->confed_peers);
      bgp->confed_peers = NULL;
    }
  else
    bgp->confed_peers = XREALLOC (MTYPE_BGP_CONFED_LIST,
				  bgp->confed_peers,
				  bgp->confed_peers_cnt * sizeof (as_t));

  /* Now reset any peer who's remote AS has just been removed from the
     CONFED */
  if (bgp_config_check (bgp, BGP_CONFIG_CONFEDERATION))
    {
      LIST_LOOP (bgp->peer, peer, nn)
	{
	  if (peer->as == as)
	    {
	      peer->local_as = bgp->confed_id;
	      if (peer->status == Established)
		{
		  peer->last_reset = PEER_DOWN_CONFED_PEER_CHANGE;
		  bgp_notify_send (peer, BGP_NOTIFY_CEASE,
				   BGP_NOTIFY_CEASE_CONFIG_CHANGE);
		}
	      else
		BGP_EVENT_ADD (peer, BGP_Stop);
	    }
	}
    }

  return 0;
}

/* Local preference configuration.  */
int
bgp_default_local_preference_set (struct bgp *bgp, u_int32_t local_pref)
{
  if (! bgp)
    return -1;

  bgp_config_set (bgp, BGP_CONFIG_DEFAULT_LOCAL_PREF);
  bgp->default_local_pref = local_pref;

  return 0;
}

int
bgp_default_local_preference_unset (struct bgp *bgp)
{
  if (! bgp)
    return -1;

  bgp_config_unset (bgp, BGP_CONFIG_DEFAULT_LOCAL_PREF);
  bgp->default_local_pref = BGP_DEFAULT_LOCAL_PREF;

  return 0;
}

/* Peer comparison function for sorting.  */
static int
peer_cmp (struct peer *p1, struct peer *p2)
{
  return sockunion_cmp (&p1->su, &p2->su);
}

int
peer_af_flag_check (struct peer *peer, afi_t afi, safi_t safi, u_int32_t flag)
{
  return CHECK_FLAG (peer->af_flags[afi][safi], flag);
}

/* Reset all address family specific configuration.  */
static void