bgp_route.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

  struct bgp_adj_out *aout;
  struct bgp_info *ri;

  if (! table)
    table = peer->bgp->rib[afi][safi];

  for (rn = bgp_table_top (table); rn; rn = bgp_route_next (rn))
    {
      for (ri = rn->info; ri; ri = ri->next)
	if (ri->peer == peer)
	  {
	    bgp_rib_remove (rn, ri, peer, afi, safi);
	    break;
	  }
      for (ain = rn->adj_in; ain; ain = ain->next)
	if (ain->peer == peer)
	  {
	    bgp_adj_in_remove (rn, ain);
	    bgp_unlock_node (rn);
	    break;
	  }
      for (aout = rn->adj_out; aout; aout = aout->next)
	if (aout->peer == peer)
	  {
	    bgp_adj_out_remove (rn, aout, peer, afi, safi);
	    bgp_unlock_node (rn);
	    break;
	  }
    }
}

void
bgp_clear_route (struct peer *peer, afi_t afi, safi_t safi)
{
  struct bgp_node *rn;
  struct bgp_table *table;

  if (! peer->afc[afi][safi])
    return;

  if (safi != SAFI_MPLS_VPN)
    bgp_clear_route_table (peer, afi, safi, NULL);
  else
    for (rn = bgp_table_top (peer->bgp->rib[afi][safi]); rn;
	 rn = bgp_route_next (rn))
      if ((table = rn->info) != NULL)
	bgp_clear_route_table (peer, afi, safi, table);
}
  
void
bgp_clear_route_all (struct peer *peer)
{
  afi_t afi;
  safi_t safi;

  for (afi = AFI_IP; afi < AFI_MAX; afi++)
    for (safi = SAFI_UNICAST; safi < SAFI_MAX; safi++)
      bgp_clear_route (peer, afi, safi);
}

void
bgp_clear_adj_in (struct peer *peer, afi_t afi, safi_t safi)
{
  struct bgp_table *table;
  struct bgp_node *rn;
  struct bgp_adj_in *ain;

  table = peer->bgp->rib[afi][safi];

  for (rn = bgp_table_top (table); rn; rn = bgp_route_next (rn))
    for (ain = rn->adj_in; ain ; ain = ain->next)
      if (ain->peer == peer)
	{
          bgp_adj_in_remove (rn, ain);
          bgp_unlock_node (rn);
          break;
	}
}

/* Delete all kernel routes. */
void
bgp_terminate ()
{
  struct bgp *bgp;
  struct listnode *nn;
  struct bgp_node *rn;
  struct bgp_table *table;
  struct bgp_info *ri;

  LIST_LOOP (bm->bgp, bgp, nn)
    {
      table = bgp->rib[AFI_IP][SAFI_UNICAST];

      for (rn = bgp_table_top (table); rn; rn = bgp_route_next (rn))
	for (ri = rn->info; ri; ri = ri->next)
	  if (CHECK_FLAG (ri->flags, BGP_INFO_SELECTED)
	      && ri->type == ZEBRA_ROUTE_BGP 
	      && ri->sub_type == BGP_ROUTE_NORMAL)
	    bgp_zebra_withdraw (&rn->p, ri);

      table = bgp->rib[AFI_IP6][SAFI_UNICAST];

      for (rn = bgp_table_top (table); rn; rn = bgp_route_next (rn))
	for (ri = rn->info; ri; ri = ri->next)
	  if (CHECK_FLAG (ri->flags, BGP_INFO_SELECTED)
	      && ri->type == ZEBRA_ROUTE_BGP 
	      && ri->sub_type == BGP_ROUTE_NORMAL)
	    bgp_zebra_withdraw (&rn->p, ri);
    }
}

void
bgp_reset ()
{
  vty_reset ();
  bgp_zclient_reset ();
  access_list_reset ();
  prefix_list_reset ();
}

/* Parse NLRI stream.  Withdraw NLRI is recognized by NULL attr
   value. */
int
bgp_nlri_parse (struct peer *peer, struct attr *attr, struct bgp_nlri *packet)
{
  u_char *pnt;
  u_char *lim;
  struct prefix p;
  int psize;
  int ret;

  /* Check peer status. */
  if (peer->status != Established)
    return 0;
  
  pnt = packet->nlri;
  lim = pnt + packet->length;

  for (; pnt < lim; pnt += psize)
    {
      /* Clear prefix structure. */
      memset (&p, 0, sizeof (struct prefix));

      /* Fetch prefix length. */
      p.prefixlen = *pnt++;
      p.family = afi2family (packet->afi);
      
      /* Already checked in nlri_sanity_check().  We do double check
         here. */
      if ((packet->afi == AFI_IP && p.prefixlen > 32)
	  || (packet->afi == AFI_IP6 && p.prefixlen > 128))
	return -1;

      /* Packet size overflow check. */
      psize = PSIZE (p.prefixlen);

      /* When packet overflow occur return immediately. */
      if (pnt + psize > lim)
	return -1;

      /* Fetch prefix from NLRI packet. */
      memcpy (&p.u.prefix, pnt, psize);

      /* Check address. */
      if (packet->afi == AFI_IP && packet->safi == SAFI_UNICAST)
	{
	  if (IN_CLASSD (ntohl (p.u.prefix4.s_addr)))
	    {
	      zlog (peer->log, LOG_ERR, 
		    "IPv4 unicast NLRI is multicast address %s",
		    inet_ntoa (p.u.prefix4));
	      bgp_notify_send (peer, 
			       BGP_NOTIFY_UPDATE_ERR, 
			       BGP_NOTIFY_UPDATE_INVAL_NETWORK);
	      return -1;
	    }
	}

#ifdef HAVE_IPV6
      /* Check address. */
      if (packet->afi == AFI_IP6 && packet->safi == SAFI_UNICAST)
	{
	  if (IN6_IS_ADDR_LINKLOCAL (&p.u.prefix6))
	    {
	      char buf[BUFSIZ];

	      zlog (peer->log, LOG_WARNING, 
		    "IPv6 link-local NLRI received %s ignore this NLRI",
		    inet_ntop (AF_INET6, &p.u.prefix6, buf, BUFSIZ));

	      continue;
	    }
	}
#endif /* HAVE_IPV6 */

      /* Normal process. */
      if (attr)
	ret = bgp_update (peer, &p, attr, packet->afi, packet->safi, 
			  ZEBRA_ROUTE_BGP, BGP_ROUTE_NORMAL, NULL, NULL, 0);
      else
	ret = bgp_withdraw (peer, &p, attr, packet->afi, packet->safi, 
			    ZEBRA_ROUTE_BGP, BGP_ROUTE_NORMAL, NULL, NULL);

      /* Address family configuration mismatch or maximum-prefix count
         overflow. */
      if (ret < 0)
	return -1;
    }

  /* Packet length consistency check. */
  if (pnt != lim)
    return -1;

  return 0;
}

/* NLRI encode syntax check routine. */
int
bgp_nlri_sanity_check (struct peer *peer, int afi, u_char *pnt,
		       bgp_size_t length)
{
  u_char *end;
  u_char prefixlen;
  int psize;

  end = pnt + length;

  /* RFC1771 6.3 The NLRI field in the UPDATE message is checked for
     syntactic validity.  If the field is syntactically incorrect,
     then the Error Subcode is set to Invalid Network Field. */

  while (pnt < end)
    {
      prefixlen = *pnt++;
      
      /* Prefix length check. */
      if ((afi == AFI_IP && prefixlen > 32)
	  || (afi == AFI_IP6 && prefixlen > 128))
	{
	  plog_err (peer->log, 
		    "%s [Error] Update packet error (wrong prefix length %d)",
		    peer->host, prefixlen);
	  bgp_notify_send (peer, BGP_NOTIFY_UPDATE_ERR, 
			   BGP_NOTIFY_UPDATE_INVAL_NETWORK);
	  return -1;
	}

      /* Packet size overflow check. */
      psize = PSIZE (prefixlen);

      if (pnt + psize > end)
	{
	  plog_err (peer->log, 
		    "%s [Error] Update packet error"
		    " (prefix data overflow prefix size is %d)",
		    peer->host, psize);
	  bgp_notify_send (peer, BGP_NOTIFY_UPDATE_ERR, 
			   BGP_NOTIFY_UPDATE_INVAL_NETWORK);
	  return -1;
	}

      pnt += psize;
    }

  /* Packet length consistency check. */
  if (pnt != end)
    {
      plog_err (peer->log,
		"%s [Error] Update packet error"
		" (prefix length mismatch with total length)",
		peer->host);
      bgp_notify_send (peer, BGP_NOTIFY_UPDATE_ERR, 
		       BGP_NOTIFY_UPDATE_INVAL_NETWORK);
      return -1;
    }
  return 0;
}

struct bgp_static *
bgp_static_new ()
{
  struct bgp_static *new;
  new = XMALLOC (MTYPE_BGP_STATIC, sizeof (struct bgp_static));
  memset (new, 0, sizeof (struct bgp_static));
  return new;
}

void
bgp_static_free (struct bgp_static *bgp_static)
{
  if (bgp_static->rmap.name)
    free (bgp_static->rmap.name);
  XFREE (MTYPE_BGP_STATIC, bgp_static);
}

void
bgp_static_update (struct bgp *bgp, struct prefix *p,
		   struct bgp_static *bgp_static, afi_t afi, safi_t safi)
{
  struct bgp_node *rn;
  struct bgp_info *ri;
  struct bgp_info *new;
  struct bgp_info info;
  struct attr attr;
  struct attr attr_tmp;
  struct attr *attr_new;
  int ret;

  rn = bgp_afi_node_get (bgp, afi, safi, p, NULL);

  bgp_attr_default_set (&attr, BGP_ORIGIN_IGP);
  if (bgp_static)
    {
      attr.nexthop = bgp_static->igpnexthop;
      attr.med = bgp_static->igpmetric;
      attr.flag |= ATTR_FLAG_BIT (BGP_ATTR_MULTI_EXIT_DISC);
    }

  /* Apply route-map. */
  if (bgp_static->rmap.name)
    {
      attr_tmp = attr;
      info.peer = bgp->peer_self;
      info.attr = &attr_tmp;

      ret = route_map_apply (bgp_static->rmap.map, p, RMAP_BGP, &info);

      if (ret == RMAP_DENYMATCH)
	{    
	  /* Free uninterned attribute. */
	  bgp_attr_flush (&attr_tmp);

	  /* Unintern original. */
	  aspath_unintern (attr.aspath);
	  bgp_static_withdraw (bgp, p, afi, safi);
	  return;
	}
      attr_new = bgp_attr_intern (&attr_tmp);
    }
  else
    attr_new = bgp_attr_intern (&attr);

  for (ri = rn->info; ri; ri = ri->next)
    if (ri->peer == bgp->peer_self && ri->type == ZEBRA_ROUTE_BGP
	&& ri->sub_type == BGP_ROUTE_STATIC)
      break;

  if (ri)
    {
      if (attrhash_cmp (ri->attr, attr_new))
	{
	  bgp_unlock_node (rn);
	  bgp_attr_unintern (attr_new);
	  aspath_unintern (attr.aspath);
	  return;
	}
      else
	{
	  /* The attribute is changed. */
	  SET_FLAG (ri->flags, BGP_INFO_ATTR_CHANGED);

	  /* Rewrite BGP route information. */
	  bgp_aggregate_decrement (bgp, p, ri, afi, safi);
	  bgp_attr_unintern (ri->attr);
	  ri->attr = attr_new;
	  ri->uptime = time (NULL);

	  /* Process change. */
	  bgp_aggregate_increment (bgp, p, ri, afi, safi);
	  bgp_process (bgp, rn, afi, safi);
	  bgp_unlock_node (rn);
	  aspath_unintern (attr.aspath);
	  return;
	}
    }

  /* Make new BGP info. */
  new = bgp_info_new ();
  new->type = ZEBRA_ROUTE_BGP;
  new->sub_type = BGP_ROUTE_STATIC;
  new->peer = bgp->peer_self;
  SET_FLAG (new->flags, BGP_INFO_VALID);
  new->attr = attr_new;
  new->uptime = time (NULL);

  /* Aggregate address increment. */
  bgp_aggregate_increment (bgp, p, new, afi, safi);
  
  /* Register new BGP information. */
  bgp_info_add (rn, new);

  /* Process change. */
  bgp_process (bgp, rn, afi, safi);

  /* Unintern original. */
  aspath_unintern (attr.aspath);
}

void
bgp_static_update_vpnv4 (struct bgp *bgp, struct prefix *p, u_int16_t afi,
			 u_char safi, struct prefix_rd *prd, u_char *tag)
{
  struct bgp_node *rn;
  struct bgp_info *new;

  rn = bgp_afi_node_get (bgp, afi, safi, p, prd);

  /* Make new BGP info. */
  new = bgp_info_new ();
  new->type = ZEBRA_ROUTE_BGP;
  new->sub_type = BGP_ROUTE_STATIC;
  new->peer = bgp->peer_self;
  new->attr = bgp_attr_default_intern (BGP_ORIGIN_IGP);
  SET_FLAG (new->flags, BGP_INFO_VALID);
  new->uptime = time (NULL);
  memcpy (new->tag, tag, 3);

  /* Aggregate address increment. */
  bgp_aggregate_increment (bgp, p, (struct bgp_info *) new, afi, safi);
  
  /* Register new BGP information. */
  bgp_info_add (rn, (struct bgp_info *) new);

  /* Process change. */
  bgp_process (bgp, rn, afi, safi);
}

void
bgp_static_withdraw (struct bgp *bgp, struct prefix *p, afi_t afi,
		     safi_t safi)
{
  struct bgp_node *rn;
  struct bgp_info *ri;

  rn = bgp_afi_node_get (bgp, afi, safi, p, NULL);

  /* Check selected route and self inserted route. */
  for (ri = rn->info; ri; ri = ri->next)
    if (ri->peer == bgp->peer_self 
	&& ri->type == ZEBRA_ROUTE_BGP
	&& ri->sub_type == BGP_ROUTE_STATIC)
      break;

  /* Withdraw static BGP route from routing table. */
  if (ri)
    {
      bgp_aggregate_decrement (bgp, p, ri, afi, safi);
      UNSET_FLAG (ri->flags, BGP_INFO_VALID);
      bgp_process (bgp, rn, afi, safi);
      bgp_info_delete (rn, ri);
      bgp_info_free (ri);
      bgp_unlock_node (rn);
    }

  /* Unlock bgp_node_lookup. */
  bgp_unlock_node (rn);
}

void
bgp_static_withdraw_vpnv4 (struct bgp *bgp, struct prefix *p, u_int16_t afi,
			   u_char safi, struct prefix_rd *prd, u_char *tag)
{
  struct bgp_node *rn;
  struct bgp_info *ri;

  rn = bgp_afi_node_get (bgp, afi, safi, p, prd);

  /* Check selected route and self inserted route. */
  for (ri = rn->info; ri; ri = ri->next)
    if (ri->peer == bgp->peer_self 
	&& ri->type == ZEBRA_ROUTE_BGP
	&& ri->sub_type == BGP_ROUTE_STATIC)
      break;

  /* Withdraw static BGP route from routing table. */
  if (ri)
    {
      bgp_aggregate_decrement (bgp, p, ri, afi, safi);
      UNSET_FLAG (ri->flags, BGP_INFO_VALID);
      bgp_process (bgp, rn, afi, safi);
      bgp_info_delete (rn, ri);
      bgp_info_free (ri);
      bgp_unlock_node (rn);
    }

  /* Unlock bgp_node_lookup. */
  bgp_unlock_node (rn);
}

/* Configure static BGP network.  When user don't run zebra, static
   route should be installed as valid.  */
int
bgp_static_set (struct vty *vty, struct bgp *bgp, char *ip_str, u_int16_t afi,
		u_char safi, char *rmap, int backdoor)
{
  int ret;
  struct prefix p;
  struct bgp_static *bgp_static;
  struct bgp_node *rn;
  int need_update = 0;

  /* Convert IP prefix string to struct prefix. */
  ret = str2prefix (ip_str, &p);
  if (! ret)