bgp_nexthop.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 nexthop scan
   Copyright (C) 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 "command.h"
#include "thread.h"
#include "prefix.h"
#include "zclient.h"
#include "stream.h"
#include "network.h"
#include "log.h"
#include "memory.h"

#include "bgpd/bgpd.h"
#include "bgpd/bgp_table.h"
#include "bgpd/bgp_route.h"
#include "bgpd/bgp_attr.h"
#include "bgpd/bgp_nexthop.h"
#include "bgpd/bgp_debug.h"
#include "bgpd/bgp_damp.h"
#include "zebra/rib.h"
#include "zebra/zserv.h"	/* For ZEBRA_SERV_PATH. */

struct bgp_nexthop_cache *zlookup_query (struct in_addr);
#ifdef HAVE_IPV6
struct bgp_nexthop_cache *zlookup_query_ipv6 (struct in6_addr *);
#endif /* HAVE_IPV6 */

/* Only one BGP scan thread are activated at the same time. */
struct thread *bgp_scan_thread = NULL;

/* BGP import thread */
struct thread *bgp_import_thread = NULL;

/* BGP scan interval. */
int bgp_scan_interval;

/* BGP import interval. */
int bgp_import_interval;

/* Route table for next-hop lookup cache. */
struct bgp_table *bgp_nexthop_cache_ipv4;
struct bgp_table *cache1;
struct bgp_table *cache2;

/* Route table for next-hop lookup cache. */
struct bgp_table *bgp_nexthop_cache_ipv6;
struct bgp_table *cache6_1;
struct bgp_table *cache6_2;

/* Route table for connected route. */
struct bgp_table *bgp_connected_ipv4;

/* Route table for connected route. */
struct bgp_table *bgp_connected_ipv6;

/* BGP nexthop lookup query client. */
static struct zclient *zlookup = NULL;

/* BGP process function. */
int bgp_process (struct bgp *, struct bgp_node *, afi_t, safi_t);

/* Add nexthop to the end of the list.  */
void
bnc_nexthop_add (struct bgp_nexthop_cache *bnc, struct nexthop *nexthop)
{
  struct nexthop *last;

  for (last = bnc->nexthop; last && last->next; last = last->next)
    ;
  if (last)
    last->next = nexthop;
  else
    bnc->nexthop = nexthop;
  nexthop->prev = last;
}

void
bnc_nexthop_free (struct bgp_nexthop_cache *bnc)
{
  struct nexthop *nexthop;
  struct nexthop *next = NULL;

  for (nexthop = bnc->nexthop; nexthop; nexthop = next)
    {
      next = nexthop->next;
      XFREE (MTYPE_NEXTHOP, nexthop);
    }
}

struct bgp_nexthop_cache *
bnc_new ()
{
  struct bgp_nexthop_cache *new;

  new = XMALLOC (MTYPE_BGP_NEXTHOP_CACHE, sizeof (struct bgp_nexthop_cache));
  memset (new, 0, sizeof (struct bgp_nexthop_cache));
  return new;
}

void
bnc_free (struct bgp_nexthop_cache *bnc)
{
  bnc_nexthop_free (bnc);
  XFREE (MTYPE_BGP_NEXTHOP_CACHE, bnc);
}

int
bgp_nexthop_same (struct nexthop *next1, struct nexthop *next2)
{
  if (next1->type != next2->type)
    return 0;

  switch (next1->type)
    {
    case ZEBRA_NEXTHOP_IPV4:
      if (! IPV4_ADDR_SAME (&next1->gate.ipv4, &next2->gate.ipv4))
	return 0;
      break;
    case ZEBRA_NEXTHOP_IFINDEX:
    case ZEBRA_NEXTHOP_IFNAME:
      if (next1->ifindex != next2->ifindex)
	return 0;
      break;
#ifdef HAVE_IPV6
    case ZEBRA_NEXTHOP_IPV6:
      if (! IPV6_ADDR_SAME (&next1->gate.ipv6, &next2->gate.ipv6))
	return 0;
      break;
    case ZEBRA_NEXTHOP_IPV6_IFINDEX:
    case ZEBRA_NEXTHOP_IPV6_IFNAME:
      if (! IPV6_ADDR_SAME (&next1->gate.ipv6, &next2->gate.ipv6))
	return 0;
      if (next1->ifindex != next2->ifindex)
	return 0;
      break;
#endif /* HAVE_IPV6 */
    }
  return 1;
}

int
bgp_nexthop_cache_changed (struct bgp_nexthop_cache *bnc1,
			   struct bgp_nexthop_cache *bnc2)
{
  int i;
  struct nexthop *next1, *next2;

  if (bnc1->nexthop_num != bnc2->nexthop_num)
    return 1;

  next1 = bnc1->nexthop;
  next2 = bnc2->nexthop;

  for (i = 0; i < bnc1->nexthop_num; i++)
    {
      if (! bgp_nexthop_same (next1, next2))
	return 1;

      next1 = next1->next;
      next2 = next2->next;
    }
  return 0;
}

/* If nexthop exists on connected network return 1. */
int
bgp_nexthop_check_ebgp (afi_t afi, struct attr *attr)
{
  struct bgp_node *rn;

  /* If zebra is not enabled return */
  if (zlookup->sock < 0)
    return 1;

  /* Lookup the address is onlink or not. */
  if (afi == AFI_IP)
    {
      rn = bgp_node_match_ipv4 (bgp_connected_ipv4, &attr->nexthop);
      if (rn)
	{
	  bgp_unlock_node (rn);
	  return 1;
	}
    }
#ifdef HAVE_IPV6
  else if (afi == AFI_IP6)
    {
      if (attr->mp_nexthop_len == 32)
	return 1;
      else if (attr->mp_nexthop_len == 16)
	{
	  if (IN6_IS_ADDR_LINKLOCAL (&attr->mp_nexthop_global))
	    return 1;

	  rn = bgp_node_match_ipv6 (bgp_connected_ipv6,
				      &attr->mp_nexthop_global);
	  if (rn)
	    {
	      bgp_unlock_node (rn);
	      return 1;
	    }
	}
    }
#endif /* HAVE_IPV6 */
  return 0;
}

#ifdef HAVE_IPV6
/* Check specified next-hop is reachable or not. */
int
bgp_nexthop_lookup_ipv6 (struct peer *peer, struct bgp_info *ri, int *changed,
			 int *metricchanged)
{
  struct bgp_node *rn;
  struct prefix p;
  struct bgp_nexthop_cache *bnc;
  struct attr *attr;

  /* If lookup is not enabled, return valid. */
  if (zlookup->sock < 0)
    {
      ri->igpmetric = 0;
      return 1;
    }

  /* Only check IPv6 global address only nexthop. */
  attr = ri->attr;

  if (attr->mp_nexthop_len != 16 
      || IN6_IS_ADDR_LINKLOCAL (&attr->mp_nexthop_global))
    return 1;

  memset (&p, 0, sizeof (struct prefix));
  p.family = AF_INET6;
  p.prefixlen = IPV6_MAX_BITLEN;
  p.u.prefix6 = attr->mp_nexthop_global;

  /* IBGP or ebgp-multihop */
  rn = bgp_node_get (bgp_nexthop_cache_ipv6, &p);

  if (rn->info)
    {
      bnc = rn->info;
      bgp_unlock_node (rn);
    }
  else
    {
      bnc = zlookup_query_ipv6 (&attr->mp_nexthop_global);
      if (bnc)
	{
	  struct bgp_table *old;
	  struct bgp_node *oldrn;
	  struct bgp_nexthop_cache *oldbnc;

	  if (changed)
	    {
	      if (bgp_nexthop_cache_ipv6 == cache6_1)
		old = cache6_2;
	      else
		old = cache6_1;

	      oldrn = bgp_node_lookup (old, &p);
	      if (oldrn)
		{
		  oldbnc = oldrn->info;

		  bnc->changed = bgp_nexthop_cache_changed (bnc, oldbnc);

		  if (bnc->metric != oldbnc->metric)
		    bnc->metricchanged = 1;
		}
	    }
	}
      else
	{
	  bnc = bnc_new ();
	  bnc->valid = 0;
	}
      rn->info = bnc;
    }

  if (changed)
    *changed = bnc->changed;

  if (metricchanged)
    *metricchanged = bnc->metricchanged;

  if (bnc->valid)
    ri->igpmetric = bnc->metric;
  else
    ri->igpmetric = 0;

  return bnc->valid;
}
#endif /* HAVE_IPV6 */

/* Check specified next-hop is reachable or not. */
int
bgp_nexthop_lookup (afi_t afi, struct peer *peer, struct bgp_info *ri,
		    int *changed, int *metricchanged)
{
  struct bgp_node *rn;
  struct prefix p;
  struct bgp_nexthop_cache *bnc;
  struct in_addr addr;

  /* If lookup is not enabled, return valid. */
  if (zlookup->sock < 0)
    {
      ri->igpmetric = 0;
      return 1;
    }

#ifdef HAVE_IPV6
  if (afi == AFI_IP6)
    return bgp_nexthop_lookup_ipv6 (peer, ri, changed, metricchanged);
#endif /* HAVE_IPV6 */

  addr = ri->attr->nexthop;

  memset (&p, 0, sizeof (struct prefix));
  p.family = AF_INET;
  p.prefixlen = IPV4_MAX_BITLEN;
  p.u.prefix4 = addr;

  /* IBGP or ebgp-multihop */
  rn = bgp_node_get (bgp_nexthop_cache_ipv4, &p);

  if (rn->info)
    {
      bnc = rn->info;
      bgp_unlock_node (rn);
    }
  else
    {
      bnc = zlookup_query (addr);
      if (bnc)
	{
	  struct bgp_table *old;
	  struct bgp_node *oldrn;
	  struct bgp_nexthop_cache *oldbnc;

	  if (changed)
	    {
	      if (bgp_nexthop_cache_ipv4 == cache1)
		old = cache2;
	      else
		old = cache1;

	      oldrn = bgp_node_lookup (old, &p);
	      if (oldrn)
		{
		  oldbnc = oldrn->info;

		  bnc->changed = bgp_nexthop_cache_changed (bnc, oldbnc);

		  if (bnc->metric != oldbnc->metric)
		    bnc->metricchanged = 1;
		}
	    }
	}
      else
	{
	  bnc = bnc_new ();
	  bnc->valid = 0;
	}
      rn->info = bnc;
    }

  if (changed)
    *changed = bnc->changed;

  if (metricchanged)
    *metricchanged = bnc->metricchanged;

  if (bnc->valid)
    ri->igpmetric = bnc->metric;
  else
    ri->igpmetric = 0;

  return bnc->valid;
}

/* Reset and free all BGP nexthop cache. */
void
bgp_nexthop_cache_reset (struct bgp_table *table)
{
  struct bgp_node *rn;
  struct bgp_nexthop_cache *bnc;

  for (rn = bgp_table_top (table); rn; rn = bgp_route_next (rn))
    if ((bnc = rn->info) != NULL)
      {
	bnc_free (bnc);
	rn->info = NULL;
	bgp_unlock_node (rn);
      }
}

void
bgp_scan_ipv4 ()
{
  struct bgp_node *rn;
  struct bgp *bgp;
  struct bgp_info *bi;
  struct bgp_info *next;
  struct peer *peer;
  struct listnode *nn;
  int valid;
  int current;
  int changed;
  int metricchanged;

  /* Change cache. */
  if (bgp_nexthop_cache_ipv4 == cache1)
    bgp_nexthop_cache_ipv4 = cache2;
  else
    bgp_nexthop_cache_ipv4 = cache1;

  /* Get default bgp. */
  bgp = bgp_get_default ();
  if (bgp == NULL)
    return;

  /* Maximum prefix check */
  LIST_LOOP (bgp->peer, peer, nn)
    {
      if (peer->status != Established)
	continue;

      if (peer->afc[AFI_IP][SAFI_UNICAST])
	bgp_maximum_prefix_overflow (peer, AFI_IP, SAFI_UNICAST, 1);
      if (peer->afc[AFI_IP][SAFI_MULTICAST])
	bgp_maximum_prefix_overflow (peer, AFI_IP, SAFI_MULTICAST, 1);
      if (peer->afc[AFI_IP][SAFI_MPLS_VPN])
	bgp_maximum_prefix_overflow (peer, AFI_IP, SAFI_MPLS_VPN, 1);
    }

  for (rn = bgp_table_top (bgp->rib[AFI_IP][SAFI_UNICAST]); rn;
       rn = bgp_route_next (rn))
    {
      for (bi = rn->info; bi; bi = next)
	{
	  next = bi->next;

	  if (bi->type == ZEBRA_ROUTE_BGP && bi->sub_type == BGP_ROUTE_NORMAL)
	    {
	      changed = 0;
	      metricchanged = 0;

	      if (peer_sort (bi->peer) == BGP_PEER_EBGP && bi->peer->ttl == 1)