zebra/zebra_rib.c

/* Routing Information Base.
 * Copyright (C) 1997, 98, 99, 2001 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 "table.h"
#include "memory.h"
#include "str.h"
#include "command.h"
#include "if.h"
#include "log.h"
#include "sockunion.h"
#include "linklist.h"
#include "thread.h"
#include "workqueue.h"

#include "zebra/rib.h"
#include "zebra/rt.h"
#include "zebra/zserv.h"
#include "zebra/redistribute.h"
#include "zebra/debug.h"

/* Default rtm_table for all clients */
extern struct zebra_t zebrad;

/* Each route type's string and default distance value. */
struct
{  
  int key;
  int distance;
} route_info[] =
{
  {ZEBRA_ROUTE_SYSTEM,    0},
  {ZEBRA_ROUTE_KERNEL,    0},
  {ZEBRA_ROUTE_CONNECT,   0},
  {ZEBRA_ROUTE_STATIC,    1},
  {ZEBRA_ROUTE_RIP,     120},
  {ZEBRA_ROUTE_RIPNG,   120},
  {ZEBRA_ROUTE_OSPF,    110},
  {ZEBRA_ROUTE_OSPF6,   110},
  {ZEBRA_ROUTE_ISIS,    115},
  {ZEBRA_ROUTE_BGP,      20  /* IBGP is 200. */}
};

struct zebra_queue_node_t
{
  struct route_node *node;
  struct rib *del;
};

/* Vector for routing table.  */
vector vrf_vector;

/* Allocate new VRF.  */
static struct vrf *
vrf_alloc (const char *name)
{
  struct vrf *vrf;

  vrf = XCALLOC (MTYPE_VRF, sizeof (struct vrf));

  /* Put name.  */
  if (name)
    vrf->name = XSTRDUP (MTYPE_VRF_NAME, name);

  /* Allocate routing table and static table.  */
  vrf->table[AFI_IP][SAFI_UNICAST] = route_table_init ();
  vrf->table[AFI_IP6][SAFI_UNICAST] = route_table_init ();
  vrf->stable[AFI_IP][SAFI_UNICAST] = route_table_init ();
  vrf->stable[AFI_IP6][SAFI_UNICAST] = route_table_init ();

  return vrf;
}

/* Free VRF.  */
static void
vrf_free (struct vrf *vrf)
{
  if (vrf->name)
    XFREE (MTYPE_VRF_NAME, vrf->name);
  XFREE (MTYPE_VRF, vrf);
}

/* Lookup VRF by identifier.  */
struct vrf *
vrf_lookup (u_int32_t id)
{
  return vector_lookup (vrf_vector, id);
}

/* Lookup VRF by name.  */
static struct vrf *
vrf_lookup_by_name (char *name)
{
  unsigned int i;
  struct vrf *vrf;

  for (i = 0; i < vector_active (vrf_vector); i++)
    if ((vrf = vector_slot (vrf_vector, i)) != NULL)
      if (vrf->name && name && strcmp (vrf->name, name) == 0)
	return vrf;
  return NULL;
}

/* Initialize VRF.  */
static void
vrf_init (void)
{
  struct vrf *default_table;

  /* Allocate VRF vector.  */
  vrf_vector = vector_init (1);

  /* Allocate default main table.  */
  default_table = vrf_alloc ("Default-IP-Routing-Table");

  /* Default table index must be 0.  */
  vector_set_index (vrf_vector, 0, default_table);
}

/* Lookup route table.  */
struct route_table *
vrf_table (afi_t afi, safi_t safi, u_int32_t id)
{
  struct vrf *vrf;

  vrf = vrf_lookup (id);
  if (! vrf)
    return NULL;

  return vrf->table[afi][safi];
}

/* Lookup static route table.  */
struct route_table *
vrf_static_table (afi_t afi, safi_t safi, u_int32_t id)
{
  struct vrf *vrf;

  vrf = vrf_lookup (id);
  if (! vrf)
    return NULL;

  return vrf->stable[afi][safi];
}

/* Add nexthop to the end of the list.  */
static void
nexthop_add (struct rib *rib, struct nexthop *nexthop)
{
  struct nexthop *last;

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

  rib->nexthop_num++;
}

/* Delete specified nexthop from the list. */
static void
nexthop_delete (struct rib *rib, struct nexthop *nexthop)
{
  if (nexthop->next)
    nexthop->next->prev = nexthop->prev;
  if (nexthop->prev)
    nexthop->prev->next = nexthop->next;
  else
    rib->nexthop = nexthop->next;
  rib->nexthop_num--;
}

/* Free nexthop. */
static void
nexthop_free (struct nexthop *nexthop)
{
  if (nexthop->ifname)
    XFREE (0, nexthop->ifname);
  XFREE (MTYPE_NEXTHOP, nexthop);
}

struct nexthop *
nexthop_ifindex_add (struct rib *rib, unsigned int ifindex)
{
  struct nexthop *nexthop;

  nexthop = XMALLOC (MTYPE_NEXTHOP, sizeof (struct nexthop));
  memset (nexthop, 0, sizeof (struct nexthop));
  nexthop->type = NEXTHOP_TYPE_IFINDEX;
  nexthop->ifindex = ifindex;

  nexthop_add (rib, nexthop);

  return nexthop;
}

struct nexthop *
nexthop_ifname_add (struct rib *rib, char *ifname)
{
  struct nexthop *nexthop;

  nexthop = XMALLOC (MTYPE_NEXTHOP, sizeof (struct nexthop));
  memset (nexthop, 0, sizeof (struct nexthop));
  nexthop->type = NEXTHOP_TYPE_IFNAME;
  nexthop->ifname = XSTRDUP (0, ifname);

  nexthop_add (rib, nexthop);

  return nexthop;
}

struct nexthop *
nexthop_ipv4_add (struct rib *rib, struct in_addr *ipv4)
{
  struct nexthop *nexthop;

  nexthop = XMALLOC (MTYPE_NEXTHOP, sizeof (struct nexthop));
  memset (nexthop, 0, sizeof (struct nexthop));
  nexthop->type = NEXTHOP_TYPE_IPV4;
  nexthop->gate.ipv4 = *ipv4;

  nexthop_add (rib, nexthop);

  return nexthop;
}

static struct nexthop *
nexthop_ipv4_ifindex_add (struct rib *rib, struct in_addr *ipv4, 
			  unsigned int ifindex)
{
  struct nexthop *nexthop;

  nexthop = XMALLOC (MTYPE_NEXTHOP, sizeof (struct nexthop));
  memset (nexthop, 0, sizeof (struct nexthop));
  nexthop->type = NEXTHOP_TYPE_IPV4_IFINDEX;
  nexthop->gate.ipv4 = *ipv4;
  nexthop->ifindex = ifindex;

  nexthop_add (rib, nexthop);

  return nexthop;
}

#ifdef HAVE_IPV6
struct nexthop *
nexthop_ipv6_add (struct rib *rib, struct in6_addr *ipv6)
{
  struct nexthop *nexthop;

  nexthop = XMALLOC (MTYPE_NEXTHOP, sizeof (struct nexthop));
  memset (nexthop, 0, sizeof (struct nexthop));
  nexthop->type = NEXTHOP_TYPE_IPV6;
  nexthop->gate.ipv6 = *ipv6;

  nexthop_add (rib, nexthop);

  return nexthop;
}

static struct nexthop *
nexthop_ipv6_ifname_add (struct rib *rib, struct in6_addr *ipv6,
			 char *ifname)
{
  struct nexthop *nexthop;

  nexthop = XMALLOC (MTYPE_NEXTHOP, sizeof (struct nexthop));
  memset (nexthop, 0, sizeof (struct nexthop));
  nexthop->type = NEXTHOP_TYPE_IPV6_IFNAME;
  nexthop->gate.ipv6 = *ipv6;
  nexthop->ifname = XSTRDUP (0, ifname);

  nexthop_add (rib, nexthop);

  return nexthop;
}

static struct nexthop *
nexthop_ipv6_ifindex_add (struct rib *rib, struct in6_addr *ipv6,
			  unsigned int ifindex)
{
  struct nexthop *nexthop;

  nexthop = XMALLOC (MTYPE_NEXTHOP, sizeof (struct nexthop));
  memset (nexthop, 0, sizeof (struct nexthop));
  nexthop->type = NEXTHOP_TYPE_IPV6_IFINDEX;
  nexthop->gate.ipv6 = *ipv6;
  nexthop->ifindex = ifindex;

  nexthop_add (rib, nexthop);

  return nexthop;
}
#endif /* HAVE_IPV6 */

struct nexthop *
nexthop_blackhole_add (struct rib *rib)
{
  struct nexthop *nexthop;

  nexthop = XMALLOC (MTYPE_NEXTHOP, sizeof (struct nexthop));
  memset (nexthop, 0, sizeof (struct nexthop));
  nexthop->type = NEXTHOP_TYPE_BLACKHOLE;
  SET_FLAG (rib->flags, ZEBRA_FLAG_BLACKHOLE);

  nexthop_add (rib, nexthop);

  return nexthop;
}

/* If force flag is not set, do not modify falgs at all for uninstall
   the route from FIB. */
static int
nexthop_active_ipv4 (struct rib *rib, struct nexthop *nexthop, int set,
		     struct route_node *top)
{
  struct prefix_ipv4 p;
  struct route_table *table;
  struct route_node *rn;
  struct rib *match;
  struct nexthop *newhop;

  if (nexthop->type == NEXTHOP_TYPE_IPV4)
    nexthop->ifindex = 0;

  if (set)
    UNSET_FLAG (nexthop->flags, NEXTHOP_FLAG_RECURSIVE);

  /* Make lookup prefix. */
  memset (&p, 0, sizeof (struct prefix_ipv4));
  p.family = AF_INET;
  p.prefixlen = IPV4_MAX_PREFIXLEN;
  p.prefix = nexthop->gate.ipv4;

  /* Lookup table.  */
  table = vrf_table (AFI_IP, SAFI_UNICAST, 0);
  if (! table)
    return 0;

  rn = route_node_match (table, (struct prefix *) &p);
  while (rn)
    {
      route_unlock_node (rn);
      
      /* If lookup self prefix return immidiately. */
      if (rn == top)
	return 0;

      /* Pick up selected route. */
      for (match = rn->info; match; match = match->next)
	if (CHECK_FLAG (match->flags, ZEBRA_FLAG_SELECTED))
	  break;

      /* If there is no selected route or matched route is EGP, go up
         tree. */
      if (! match 
	  || match->type == ZEBRA_ROUTE_BGP)
	{
	  do {
	    rn = rn->parent;
	  } while (rn && rn->info == NULL);
	  if (rn)
	    route_lock_node (rn);
	}
      else
	{
	  if (match->type == ZEBRA_ROUTE_CONNECT)
	    {
	      /* Directly point connected route. */
	      newhop = match->nexthop;
	      if (newhop && nexthop->type == NEXTHOP_TYPE_IPV4)
		nexthop->ifindex = newhop->ifindex;
	      
	      return 1;
	    }
	  else if (CHECK_FLAG (rib->flags, ZEBRA_FLAG_INTERNAL))
	    {
	      for (newhop = match->nexthop; newhop; newhop = newhop->next)
		if (CHECK_FLAG (newhop->flags, NEXTHOP_FLAG_FIB)
		    && ! CHECK_FLAG (newhop->flags, NEXTHOP_FLAG_RECURSIVE))
		  {
		    if (set)
		      {
			SET_FLAG (nexthop->flags, NEXTHOP_FLAG_RECURSIVE);
			nexthop->rtype = newhop->type;
			if (newhop->type == NEXTHOP_TYPE_IPV4 ||
			    newhop->type == NEXTHOP_TYPE_IPV4_IFINDEX)
			  nexthop->rgate.ipv4 = newhop->gate.ipv4;
			if (newhop->type == NEXTHOP_TYPE_IFINDEX
			    || newhop->type == NEXTHOP_TYPE_IFNAME
			    || newhop->type == NEXTHOP_TYPE_IPV4_IFINDEX)
			  nexthop->rifindex = newhop->ifindex;
		      }
		    return 1;
		  }
	      return 0;
	    }
	  else
	    {
	      return 0;
	    }
	}
    }
  return 0;
}

#ifdef HAVE_IPV6
/* If force flag is not set, do not modify falgs at all for uninstall
   the route from FIB. */
static int
nexthop_active_ipv6 (struct rib *rib, struct nexthop *nexthop, int set,
		     struct route_node *top)
{
  struct prefix_ipv6 p;
  struct route_table *table;
  struct route_node *rn;
  struct rib *match;
  struct nexthop *newhop;

  if (nexthop->type == NEXTHOP_TYPE_IPV6)
    nexthop->ifindex = 0;

  if (set)
    UNSET_FLAG (nexthop->flags, NEXTHOP_FLAG_RECURSIVE);

  /* Make lookup prefix. */
  memset (&p, 0, sizeof (struct prefix_ipv6));
  p.family = AF_INET6;
  p.prefixlen = IPV6_MAX_PREFIXLEN;
  p.prefix = nexthop->gate.ipv6;

  /* Lookup table.  */
  table = vrf_table (AFI_IP6, SAFI_UNICAST, 0);
  if (! table)
    return 0;

  rn = route_node_match (table, (struct prefix *) &p);
  while (rn)
    {
      route_unlock_node (rn);
      
      /* If lookup self prefix return immidiately. */
      if (rn == top)
	return 0;

      /* Pick up selected route. */
      for (match = rn->info; match; match = match->next)
	if (CHECK_FLAG (match->flags, ZEBRA_FLAG_SELECTED))
	  break;

      /* If there is no selected route or matched route is EGP, go up
         tree. */
      if (! match
	  || match->type == ZEBRA_ROUTE_BGP)
	{
	  do {
	    rn = rn->parent;
	  } while (rn && rn->info == NULL);
	  if (rn)
	    route_lock_node (rn);
	}
      else
	{
	  if (match->type == ZEBRA_ROUTE_CONNECT)
	    {
	      /* Directly point connected route. */
	      newhop = match->nexthop;

	      if (newhop && nexthop->type == NEXTHOP_TYPE_IPV6)
		nexthop->ifindex = newhop->ifindex;
	      
	      return 1;
	    }
	  else if (CHECK_FLAG (rib->flags, ZEBRA_FLAG_INTERNAL))
	    {
	      for (newhop = match->nexthop; newhop; newhop = newhop->next)
		if (CHECK_FLAG (newhop->flags, NEXTHOP_FLAG_FIB)
		    && ! CHECK_FLAG (newhop->flags, NEXTHOP_FLAG_RECURSIVE))
		  {
		    if (set)
		      {
			SET_FLAG (nexthop->flags, NEXTHOP_FLAG_RECURSIVE);
			nexthop->rtype = newhop->type;
			if (newhop->type == NEXTHOP_TYPE_IPV6
			    || newhop->type == NEXTHOP_TYPE_IPV6_IFINDEX
			    || newhop->type == NEXTHOP_TYPE_IPV6_IFNAME)
			  nexthop->rgate.ipv6 = newhop->gate.ipv6;
			if (newhop->type == NEXTHOP_TYPE_IFINDEX
			    || newhop->type == NEXTHOP_TYPE_IFNAME
			    || newhop->type == NEXTHOP_TYPE_IPV6_IFINDEX
			    || newhop->type == NEXTHOP_TYPE_IPV6_IFNAME)
			  nexthop->rifindex = newhop->ifindex;
		      }
		    return 1;
		  }
	      return 0;
	    }
	  else
	    {
	      return 0;
	    }
	}
    }
  return 0;
}
#endif /* HAVE_IPV6 */

struct rib *
rib_match_ipv4 (struct in_addr addr)
{
  struct prefix_ipv4 p;
  struct route_table *table;
  struct route_node *rn;
  struct rib *match;
  struct nexthop *newhop;

  /* Lookup table.  */
  table = vrf_table (AFI_IP, SAFI_UNICAST, 0);
  if (! table)
    return 0;

  memset (&p, 0, sizeof (struct prefix_ipv4));
  p.family = AF_INET;
  p.prefixlen = IPV4_MAX_PREFIXLEN;
  p.prefix = addr;

  rn = route_node_match (table, (struct prefix *) &p);

  while (rn)
    {
      route_unlock_node (rn);
      
      /* Pick up selected route. */
      for (match = rn->info; match; match = match->next)
	if (CHECK_FLAG (match->flags, ZEBRA_FLAG_SELECTED))
	  break;

      /* If there is no selected route or matched route is EGP, go up
         tree. */
      if (! match 
	  || match->type == ZEBRA_ROUTE_BGP)
	{
	  do {
	    rn = rn->parent;
	  } while (rn && rn->info == NULL);
	  if (rn)
	    route_lock_node (rn);
	}
      else
	{
	  if (match->type == ZEBRA_ROUTE_CONNECT)
	    /* Directly point connected route. */
	    return match;
	  else
	    {
	      for (newhop = match->nexthop; newhop; newhop = newhop->next)
		if (CHECK_FLAG (newhop->flags, NEXTHOP_FLAG_FIB))
		  return match;
	      return NULL;
	    }
	}
    }
  return NULL;
}

struct rib *
rib_lookup_ipv4 (struct prefix_ipv4 *p)
{
  struct route_table *table;
  struct route_node *rn;
  struct rib *match;
  struct nexthop *nexthop;

  /* Lookup table.  */
  table = vrf_table (AFI_IP, SAFI_UNICAST, 0);
  if (! table)
    return 0;

  rn = route_node_lookup (table, (struct prefix *) p);

  /* No route for this prefix. */
  if (! rn)
    return NULL;

  /* Unlock node. */
  route_unlock_node (rn);

  /* Pick up selected route. */
  for (match = rn->info; match; match = match->next)
    if (CHECK_FLAG (match->flags, ZEBRA_FLAG_SELECTED))
      break;

  if (! match || match->type == ZEBRA_ROUTE_BGP)
    return NULL;

  if (match->type == ZEBRA_ROUTE_CONNECT)
    return match;
  
  for (nexthop = match->nexthop; nexthop; nexthop = nexthop->next)
    if (CHECK_FLAG (nexthop->flags, NEXTHOP_FLAG_FIB))
      return match;

  return NULL;
}

#ifdef HAVE_IPV6
struct rib *
rib_match_ipv6 (struct in6_addr *addr)
{
  struct prefix_ipv6 p;
  struct route_table *table;
  struct route_node *rn;
  struct rib *match;
  struct nexthop *newhop;

  /* Lookup table.  */
  table = vrf_table (AFI_IP6, SAFI_UNICAST, 0);
  if (! table)
    return 0;

  memset (&p, 0, sizeof (struct prefix_ipv6));
  p.family = AF_INET6;
  p.prefixlen = IPV6_MAX_PREFIXLEN;
  IPV6_ADDR_COPY (&p.prefix, addr);

  rn = route_node_match (table, (struct prefix *) &p);

  while (rn)
    {
      route_unlock_node (rn);
      
      /* Pick up selected route. */
      for (match = rn->info; match; match = match->next)
	if (CHECK_FLAG (match->flags, ZEBRA_FLAG_SELECTED))
	  break;

      /* If there is no selected route or matched route is EGP, go up
         tree. */
      if (! match 
	  || match->type == ZEBRA_ROUTE_BGP)
	{
	  do {
	    rn = rn->parent;
	  } while (rn && rn->info == NULL);
	  if (rn)
	    route_lock_node (rn);
	}
      else
	{
	  if (match->type == ZEBRA_ROUTE_CONNECT)
	    /* Directly point connected route. */
	    return match;
	  else
	    {
	      for (newhop = match->nexthop; newhop; newhop = newhop->next)
		if (CHECK_FLAG (newhop->flags, NEXTHOP_FLAG_FIB))
		  return match;
	      return NULL;
	    }
	}
    }
  return NULL;
}
#endif /* HAVE_IPV6 */

static int
nexthop_active_check (struct route_node *rn, struct rib *rib,
		      struct nexthop *nexthop, int set)
{
  struct interface *ifp;

  switch (nexthop->type)
    {
    case NEXTHOP_TYPE_IFINDEX:
      ifp = if_lookup_by_index (nexthop->ifindex);
      if (ifp && if_is_up (ifp))
	SET_FLAG (nexthop->flags, NEXTHOP_FLAG_ACTIVE);
      else
	UNSET_FLAG (nexthop->flags, NEXTHOP_FLAG_ACTIVE);
      break;
    case NEXTHOP_TYPE_IFNAME:
    case NEXTHOP_TYPE_IPV6_IFNAME:
      ifp = if_lookup_by_name (nexthop->ifname);
      if (ifp && if_is_up (ifp))
	{
	  if (set)
	    nexthop->ifindex = ifp->ifindex;
	  SET_FLAG (nexthop->flags, NEXTHOP_FLAG_ACTIVE);
	}
      else
	{
	  if (set)
	    nexthop->ifindex = 0;
	  UNSET_FLAG (nexthop->flags, NEXTHOP_FLAG_ACTIVE);
	}
      break;
    case NEXTHOP_TYPE_IPV4:
    case NEXTHOP_TYPE_IPV4_IFINDEX:
      if (nexthop_active_ipv4 (rib, nexthop, set, rn))
	SET_FLAG (nexthop->flags, NEXTHOP_FLAG_ACTIVE);
      else
	UNSET_FLAG (nexthop->flags, NEXTHOP_FLAG_ACTIVE);
      break;
#ifdef HAVE_IPV6
    case NEXTHOP_TYPE_IPV6:
      if (nexthop_active_ipv6 (rib, nexthop, set, rn))
	SET_FLAG (nexthop->flags, NEXTHOP_FLAG_ACTIVE);
      else
	UNSET_FLAG (nexthop->flags, NEXTHOP_FLAG_ACTIVE);
      break;
    case NEXTHOP_TYPE_IPV6_IFINDEX:
      if (IN6_IS_ADDR_LINKLOCAL (&nexthop->gate.ipv6))
	{
	  ifp = if_lookup_by_index (nexthop->ifindex);
	  if (ifp && if_is_up (ifp))
	    SET_FLAG (nexthop->flags, NEXTHOP_FLAG_ACTIVE);
	  else
	    UNSET_FLAG (nexthop->flags, NEXTHOP_FLAG_ACTIVE);
	}
      else
	{
	  if (nexthop_active_ipv6 (rib, nexthop, set, rn))
	    SET_FLAG (nexthop->flags, NEXTHOP_FLAG_ACTIVE);
	  else
	    UNSET_FLAG (nexthop->flags, NEXTHOP_FLAG_ACTIVE);
	}
      break;
#endif /* HAVE_IPV6 */
    case NEXTHOP_TYPE_BLACKHOLE:
      SET_FLAG (nexthop->flags, NEXTHOP_FLAG_ACTIVE);
      break;
    default:
      break;
    }
  return CHECK_FLAG (nexthop->flags, NEXTHOP_FLAG_ACTIVE);
}

static int
nexthop_active_update (struct route_node *rn, struct rib *rib, int set)
{
  struct nexthop *nexthop;
  int active;

  rib->nexthop_active_num = 0;
  UNSET_FLAG (rib->flags, ZEBRA_FLAG_CHANGED);

  for (nexthop = rib->nexthop; nexthop; nexthop = nexthop->next)
    {
      active = CHECK_FLAG (nexthop->flags, NEXTHOP_FLAG_ACTIVE);

      nexthop_active_check (rn, rib, nexthop, set);
      if ((MULTIPATH_NUM == 0 || rib->nexthop_active_num < MULTIPATH_NUM)
          && active != CHECK_FLAG (nexthop->flags, NEXTHOP_FLAG_ACTIVE))
        SET_FLAG (rib->flags, ZEBRA_FLAG_CHANGED);

      if (CHECK_FLAG (nexthop->flags, NEXTHOP_FLAG_ACTIVE))
        rib->nexthop_active_num++;
    }
  return rib->nexthop_active_num;
}


#define RIB_SYSTEM_ROUTE(R) \
        ((R)->type == ZEBRA_ROUTE_KERNEL || (R)->type == ZEBRA_ROUTE_CONNECT)

static struct rib *
rib_lock (struct rib *rib)
{
  assert (rib->lock >= 0);
  
  rib->lock++;
  return rib;
}

static struct rib *
rib_unlock (struct rib *rib)
{
  struct nexthop *nexthop;
  struct nexthop *next;
  
  assert (rib->lock > 0);
  rib->lock--;

  if (rib->lock == 0)
    {
      for (nexthop = rib->nexthop; nexthop; nexthop = next)
        {
          next = nexthop->next;
          nexthop_free (nexthop);
        }
      XFREE (MTYPE_RIB, rib);
      return NULL;
    }
  return rib;
}

static void
rib_install_kernel (struct route_node *rn, struct rib *rib)
{
  int ret = 0;
  struct nexthop *nexthop;

  switch (PREFIX_FAMILY (&rn->p))
    {
    case AF_INET:
      ret = kernel_add_ipv4 (&rn->p, rib);
      break;
#ifdef HAVE_IPV6
    case AF_INET6:
      ret = kernel_add_ipv6 (&rn->p, rib);
      break;
#endif /* HAVE_IPV6 */
    }

  if (ret < 0)
    {
      for (nexthop = rib->nexthop; nexthop; nexthop = nexthop->next)
	UNSET_FLAG (nexthop->flags, NEXTHOP_FLAG_FIB);
    }
}

/* Uninstall the route from kernel. */
static int
rib_uninstall_kernel (struct route_node *rn, struct rib *rib)
{
  int ret = 0;
  struct nexthop *nexthop;

  switch (PREFIX_FAMILY (&rn->p))
    {
    case AF_INET:
      ret = kernel_delete_ipv4 (&rn->p, rib);
      break;
#ifdef HAVE_IPV6
    case AF_INET6:
      ret = kernel_delete_ipv6 (&rn->p, rib);
      break;
#endif /* HAVE_IPV6 */
    }

  for (nexthop = rib->nexthop; nexthop; nexthop = nexthop->next)
    UNSET_FLAG (nexthop->flags, NEXTHOP_FLAG_FIB);

  return ret;
}

/* Uninstall the route from kernel. */
static void
rib_uninstall (struct route_node *rn, struct rib *rib)
{
  if (CHECK_FLAG (rib->flags, ZEBRA_FLAG_SELECTED))
    {
      redistribute_delete (&rn->p, rib);
      if (! RIB_SYSTEM_ROUTE (rib))
	rib_uninstall_kernel (rn, rib);
      UNSET_FLAG (rib->flags, ZEBRA_FLAG_SELECTED);
    }
}

/* Core function for processing routing information base. */
static wq_item_status
rib_process (struct work_queue *wq, void *data)
{
  struct zebra_queue_node_t *qnode = data;
  struct rib *rib;
  struct rib *next;
  struct rib *fib = NULL;
  struct rib *select = NULL;
  struct rib *del = qnode->del;
  struct route_node *rn = qnode->node;
  int installed = 0;
  struct nexthop *nexthop = NULL;
  
  assert (rn);
  
  /* possibly should lock and unlock rib on each iteration. however, for
   * now, we assume called functions are synchronous and dont delete RIBs
   * (as the work-queue deconstructor for this function is supposed to be
   * the canonical 'delete' path for RIBs). Further if called functions
   * below were to made asynchronous they should themselves acquire any
   * locks/refcounts as needed and not depend on this caller to do it for
   * them
   */
  for (rib = rn->info; rib; rib = next)
    {
      next = rib->next;
      
      /* Currently installed rib. */
      if (CHECK_FLAG (rib->flags, ZEBRA_FLAG_SELECTED))
        fib = rib;
      
      /* Skip unreachable nexthop. */
      if (! nexthop_active_update (rn, rib, 0))
        continue;

      /* Infinit distance. */
      if (rib->distance == DISTANCE_INFINITY)
        continue;

      /* Newly selected rib, the common case. */
      if (!select)
        {
          select = rib;
          continue;
        }
      
      /* filter route selection in following order:
       * - connected beats other types
       * - lower distance beats higher
       * - lower metric beats higher for equal distance
       * - last, hence oldest, route wins tie break.
       */
      
      /* Connected routes. Pick the last connected
       * route of the set of lowest metric connected routes.
       */
      if (rib->type == ZEBRA_ROUTE_CONNECT)
        {
          if (select->type != ZEBRA_ROUTE_CONNECT
              || rib->metric <= select->metric)
            select = rib;
          continue;
        }
      else if (select->type == ZEBRA_ROUTE_CONNECT)
        continue;
      
      /* higher distance loses */
      if (rib->distance > select->distance)
        continue;
      
      /* lower wins */
      if (rib->distance < select->distance)
        {
          select = rib;
          continue;
        }
      
      /* metric tie-breaks equal distance */
      if (rib->metric <= select->metric)
        select = rib;
    }
  
  /* Deleted route check. */
  if (del && CHECK_FLAG (del->flags, ZEBRA_FLAG_SELECTED))
    fib = del;
  
  /* We possibly should lock fib and select here However, all functions
   * below are 'inline' and not asynchronous And if any were to be
   * converted, they should manage references themselves really..  See
   * previous comment above.
   */
  
  /* Same route is selected. */
  if (select && select == fib)
    {
      if (CHECK_FLAG (select->flags, ZEBRA_FLAG_CHANGED))
        {
          redistribute_delete (&rn->p, select);
          if (! RIB_SYSTEM_ROUTE (select))
            rib_uninstall_kernel (rn, select);

          /* Set real nexthop. */
          nexthop_active_update (rn, select, 1);
  
          if (! RIB_SYSTEM_ROUTE (select))
            rib_install_kernel (rn, select);
          redistribute_add (&rn->p, select);
        }
      else if (! RIB_SYSTEM_ROUTE (select))
        {
          /* Housekeeping code to deal with 
             race conditions in kernel with linux
             netlink reporting interface up before IPv4 or IPv6 protocol
             is ready to add routes.
             This makes sure the routes are IN the kernel.
           */

          for (nexthop = select->nexthop; nexthop; nexthop = nexthop->next)
            {
              if (CHECK_FLAG (nexthop->flags, NEXTHOP_FLAG_FIB))
                installed = 1;
            }
          if (! installed) 
            rib_install_kernel (rn, select);
        }
      return WQ_SUCCESS;
    }

  /* Uninstall old rib from forwarding table. */
  if (fib)
    {
      redistribute_delete (&rn->p, fib);
      if (! RIB_SYSTEM_ROUTE (fib))
	rib_uninstall_kernel (rn, fib);
      UNSET_FLAG (fib->flags, ZEBRA_FLAG_SELECTED);

      /* Set real nexthop. */
      nexthop_active_update (rn, fib, 1);
    }

  /* Install new rib into forwarding table. */
  if (select)
    {
      /* Set real nexthop. */
      nexthop_active_update (rn, select, 1);

      if (! RIB_SYSTEM_ROUTE (select))
        rib_install_kernel (rn, select);
      SET_FLAG (select->flags, ZEBRA_FLAG_SELECTED);
      redistribute_add (&rn->p, select);
    }

  return WQ_SUCCESS;

}

/* Add work queue item to work queue and schedule processing */
static void
rib_queue_add_qnode (struct zebra_t *zebra, struct zebra_queue_node_t *qnode)
{
  route_lock_node (qnode->node);
  
  if (IS_ZEBRA_DEBUG_EVENT)
    zlog_info ("rib_queue_add_qnode: work queue added");

  assert (zebra && qnode && qnode->node);

  if (qnode->del)
    rib_lock (qnode->del);
  
  if (zebra->ribq == NULL)
    {
      zlog_err ("rib_queue_add_qnode: ribq work_queue does not exist!");
      route_unlock_node (qnode->node);
      return;
    }
  
  work_queue_add (zebra->ribq, qnode);

  return;
}

/* Add route node and rib to work queue and schedule processing */
static void
rib_queue_add (struct zebra_t *zebra, struct route_node *rn, struct rib *del)
{
 struct zebra_queue_node_t *qnode;

 assert (zebra && rn);
 
 qnode = (struct zebra_queue_node_t *) 
          XCALLOC (MTYPE_RIB_QUEUE, sizeof (struct zebra_queue_node_t));
 
 if (qnode == NULL)
   {
     zlog_err ("rib_queue_add: failed to allocate queue node memory, %s",
               strerror (errno));
     return;
   }

 qnode->node = rn;
 qnode->del = del;
 
 rib_queue_add_qnode (zebra, qnode);

 return;
}

/* free zebra_queue_node_t */
static void
rib_queue_qnode_del (struct work_queue *wq, void *data)
{
  struct zebra_queue_node_t *qnode = data;
  route_unlock_node (qnode->node);
  
  if (qnode->del)
    rib_unlock (qnode->del);
  
  XFREE (MTYPE_RIB_QUEUE, qnode);
}

/* initialise zebra rib work queue */
static void
rib_queue_init (struct zebra_t *zebra)
{
  assert (zebra);
  
  if (! (zebra->ribq = work_queue_new (zebra->master, 
                                       "zebra_rib_work_queue")))
    {
      zlog_err ("rib_queue_init: could not initialise work queue!");
      return;
    }

  /* fill in the work queue spec */
  zebra->ribq->spec.workfunc = &rib_process;
  zebra->ribq->spec.errorfunc = NULL;
  zebra->ribq->spec.del_item_data = &rib_queue_qnode_del;
  /* XXX: TODO: These should be runtime configurable via vty */
  zebra->ribq->spec.max_retries = 3;
  
  return;
}

/* Add RIB to head of the route node. */
static void
rib_addnode (struct route_node *rn, struct rib *rib)
{
  struct rib *head;
  
  assert (rib && rn);
  
  rib_lock (rib);
  route_lock_node (rn);
  
  head = rn->info;
  if (head)
    head->prev = rib;
  rib->next = head;
  rn->info = rib;
}

static void
rib_delnode (struct route_node *rn, struct rib *rib)
{
  assert (rn && rib);
  
  if (rib->next)
    rib->next->prev = rib->prev;
  if (rib->prev)
    rib->prev->next = rib->next;
  else
    rn->info = rib->next;
  
  rib_unlock (rib);
  route_unlock_node (rn);
}

int
rib_add_ipv4 (int type, int flags, struct prefix_ipv4 *p, 
	      struct in_addr *gate, unsigned int ifindex, u_int32_t vrf_id,
	      u_int32_t metric, u_char distance)
{
  struct rib *rib;
  struct rib *same = NULL;
  struct route_table *table;
  struct route_node *rn;
  struct nexthop *nexthop;

  /* Lookup table.  */
  table = vrf_table (AFI_IP, SAFI_UNICAST, 0);
  if (! table)
    return 0;

  /* Make it sure prefixlen is applied to the prefix. */
  apply_mask_ipv4 (p);

  /* Set default distance by route type. */
  if (distance == 0)
    {
      distance = route_info[type].distance;

      /* iBGP distance is 200. */
      if (type == ZEBRA_ROUTE_BGP && CHECK_FLAG (flags, ZEBRA_FLAG_IBGP))
	distance = 200;
    }

  /* Lookup route node.*/
  rn = route_node_get (table, (struct prefix *) p);

  /* If same type of route are installed, treat it as a implicit
     withdraw. */
  for (rib = rn->info; rib; rib = rib->next)
    {
      if (rib->type != type)
	continue;
      if (rib->type != ZEBRA_ROUTE_CONNECT)
        {
          same = rib;
          break;
        }
      /* Duplicate connected route comes in. */
      else if ((nexthop = rib->nexthop) &&
	       nexthop->type == NEXTHOP_TYPE_IFINDEX &&
	       nexthop->ifindex == ifindex)
	{
	  rib->refcnt++;
	  return 0 ;
	}
    }

  /* Allocate new rib structure. */
  rib = XCALLOC (MTYPE_RIB, sizeof (struct rib));
  rib->type = type;
  rib->distance = distance;
  rib->flags = flags;
  rib->metric = metric;
  rib->table = vrf_id;
  rib->nexthop_num = 0;
  rib->uptime = time (NULL);

  /* Nexthop settings. */
  if (gate)
    {
      if (ifindex)
	nexthop_ipv4_ifindex_add (rib, gate, ifindex);
      else
	nexthop_ipv4_add (rib, gate);
    }
  else
    nexthop_ifindex_add (rib, ifindex);

  /* If this route is kernel route, set FIB flag to the route. */
  if (type == ZEBRA_ROUTE_KERNEL || type == ZEBRA_ROUTE_CONNECT)
    for (nexthop = rib->nexthop; nexthop; nexthop = nexthop->next)
      SET_FLAG (nexthop->flags, NEXTHOP_FLAG_FIB);

  /* Link new rib to node.*/
  rib_addnode (rn, rib);
  
  /* Process this route node. */
  rib_queue_add (&zebrad, rn, same);
  
  /* Free implicit route.*/
  if (same)
    rib_delnode (rn, same);
  
  route_unlock_node (rn);
  return 0;
}

int
rib_add_ipv4_multipath (struct prefix_ipv4 *p, struct rib *rib)
{
  struct route_table *table;
  struct route_node *rn;
  struct rib *same;
  struct nexthop *nexthop;
  
  /* Lookup table.  */
  table = vrf_table (AFI_IP, SAFI_UNICAST, 0);
  if (! table)
    return 0;
  /* Make it sure prefixlen is applied to the prefix. */
  apply_mask_ipv4 (p);

  /* Set default distance by route type. */
  if (rib->distance == 0)
    {
      rib->distance = route_info[rib->type].distance;

      /* iBGP distance is 200. */
      if (rib->type == ZEBRA_ROUTE_BGP 
	  && CHECK_FLAG (rib->flags, ZEBRA_FLAG_IBGP))
	rib->distance = 200;
    }

  /* Lookup route node.*/
  rn = route_node_get (table, (struct prefix *) p);

  /* If same type of route are installed, treat it as a implicit
     withdraw. */
  for (same = rn->info; same; same = same->next)
    {
      if (same->type == rib->type && same->table == rib->table
	  && same->type != ZEBRA_ROUTE_CONNECT)
        break;
    }
  
  /* If this route is kernel route, set FIB flag to the route. */
  if (rib->type == ZEBRA_ROUTE_KERNEL || rib->type == ZEBRA_ROUTE_CONNECT)
    for (nexthop = rib->nexthop; nexthop; nexthop = nexthop->next)
      SET_FLAG (nexthop->flags, NEXTHOP_FLAG_FIB);

  /* Link new rib to node.*/
  rib_addnode (rn, rib);

  /* Process this route node. */
  rib_queue_add (&zebrad, rn, same);

  /* Free implicit route.*/
  if (same)
    rib_delnode (rn, same);
  
  route_unlock_node (rn);
  return 0;
}

/* XXX factor with rib_delete_ipv6 */
int
rib_delete_ipv4 (int type, int flags, struct prefix_ipv4 *p,
		 struct in_addr *gate, unsigned int ifindex, u_int32_t vrf_id)
{
  struct route_table *table;
  struct route_node *rn;
  struct rib *rib;
  struct rib *fib = NULL;
  struct rib *same = NULL;
  struct nexthop *nexthop;
  char buf1[BUFSIZ];
  char buf2[BUFSIZ];

  /* Lookup table.  */
  table = vrf_table (AFI_IP, SAFI_UNICAST, 0);
  if (! table)
    return 0;

  /* Apply mask. */
  apply_mask_ipv4 (p);

  if (IS_ZEBRA_DEBUG_KERNEL && gate)
    zlog_debug ("rib_delete_ipv4(): route delete %s/%d via %s ifindex %d",
		       inet_ntop (AF_INET, &p->prefix, buf1, BUFSIZ),
		       p->prefixlen, 
		       inet_ntoa (*gate), 
		       ifindex);

  /* Lookup route node. */
  rn = route_node_lookup (table, (struct prefix *) p);
  if (! rn)
    {
      if (IS_ZEBRA_DEBUG_KERNEL)
	{
	  if (gate)
	    zlog_debug ("route %s/%d via %s ifindex %d doesn't exist in rib",
		       inet_ntop (AF_INET, &p->prefix, buf1, BUFSIZ),
		       p->prefixlen,
		       inet_ntop (AF_INET, gate, buf2, BUFSIZ),
		       ifindex);
	  else
	    zlog_debug ("route %s/%d ifindex %d doesn't exist in rib",
		       inet_ntop (AF_INET, &p->prefix, buf1, BUFSIZ),
		       p->prefixlen,
		       ifindex);
	}
      return ZEBRA_ERR_RTNOEXIST;
    }

  /* Lookup same type route. */
  for (rib = rn->info; rib; rib = rib->next)
    {
      if (CHECK_FLAG (rib->flags, ZEBRA_FLAG_SELECTED))
	fib = rib;

      if (rib->type != type)
	continue;
      if (rib->type == ZEBRA_ROUTE_CONNECT && (nexthop = rib->nexthop) &&
	  nexthop->type == NEXTHOP_TYPE_IFINDEX && nexthop->ifindex == ifindex)
	{
	  if (rib->refcnt)
	    {
	      rib->refcnt--;
	      route_unlock_node (rn);
	      route_unlock_node (rn);
	      return 0;
	    }
	  same = rib;
	  break;
	}
      /* Make sure that the route found has the same gateway. */
      else if (gate == NULL ||
	       ((nexthop = rib->nexthop) &&
	        (IPV4_ADDR_SAME (&nexthop->gate.ipv4, gate) ||
		 IPV4_ADDR_SAME (&nexthop->rgate.ipv4, gate)))) 
        {
	  same = rib;
	  break;
	}
    }

  /* If same type of route can't be found and this message is from
     kernel. */
  if (! same)
    {
      if (fib && type == ZEBRA_ROUTE_KERNEL)
	{
	  /* Unset flags. */
	  for (nexthop = fib->nexthop; nexthop; nexthop = nexthop->next)
	    UNSET_FLAG (nexthop->flags, NEXTHOP_FLAG_FIB);

	  UNSET_FLAG (fib->flags, ZEBRA_FLAG_SELECTED);
	}
      else
	{
	  if (IS_ZEBRA_DEBUG_KERNEL)
	    {
	      if (gate)
		zlog_debug ("route %s/%d via %s ifindex %d type %d doesn't exist in rib",
			   inet_ntop (AF_INET, &p->prefix, buf1, BUFSIZ),
			   p->prefixlen,
			   inet_ntop (AF_INET, gate, buf2, BUFSIZ),
			   ifindex,
			   type);
	      else
		zlog_debug ("route %s/%d ifindex %d type %d doesn't exist in rib",
			   inet_ntop (AF_INET, &p->prefix, buf1, BUFSIZ),
			   p->prefixlen,
			   ifindex,
			   type);
	    }
	  route_unlock_node (rn);
	  return ZEBRA_ERR_RTNOEXIST;
	}
    }
  
  /* Process changes. */
  rib_queue_add (&zebrad, rn, same);

  if (same)
    rib_delnode (rn, same);
  
  route_unlock_node (rn);
  return 0;
}

/* Install static route into rib. */
static void
static_install_ipv4 (struct prefix *p, struct static_ipv4 *si)
{
  struct rib *rib;
  struct route_node *rn;
  struct route_table *table;

  /* Lookup table.  */
  table = vrf_table (AFI_IP, SAFI_UNICAST, 0);
  if (! table)
    return;

  /* Lookup existing route */
  rn = route_node_get (table, p);
  for (rib = rn->info; rib; rib = rib->next)
    if (rib->type == ZEBRA_ROUTE_STATIC && rib->distance == si->distance)
      break;

  if (rib)
    {
      /* Same distance static route is there.  Update it with new
         nexthop. */
      route_unlock_node (rn);
      switch (si->type)
        {
          case STATIC_IPV4_GATEWAY:
            nexthop_ipv4_add (rib, &si->gate.ipv4);
            break;
          case STATIC_IPV4_IFNAME:
            nexthop_ifname_add (rib, si->gate.ifname);
            break;
          case STATIC_IPV4_BLACKHOLE:
            nexthop_blackhole_add (rib);
            break;
        }
      rib_queue_add (&zebrad, rn, NULL);
    }
  else
    {
      /* This is new static route. */
      rib = XCALLOC (MTYPE_RIB, sizeof (struct rib));
      
      rib->type = ZEBRA_ROUTE_STATIC;
      rib->distance = si->distance;
      rib->metric = 0;
      rib->nexthop_num = 0;

      switch (si->type)
        {
          case STATIC_IPV4_GATEWAY:
            nexthop_ipv4_add (rib, &si->gate.ipv4);
            break;
          case STATIC_IPV4_IFNAME:
            nexthop_ifname_add (rib, si->gate.ifname);
            break;
          case STATIC_IPV4_BLACKHOLE:
            nexthop_blackhole_add (rib);
            break;
        }

      /* Save the flags of this static routes (reject, blackhole) */
      rib->flags = si->flags;

      /* Link this rib to the tree. */
      rib_addnode (rn, rib);

      /* Process this prefix. */
      rib_queue_add (&zebrad, rn, NULL);
    }
}

static int
static_ipv4_nexthop_same (struct nexthop *nexthop, struct static_ipv4 *si)
{
  if (nexthop->type == NEXTHOP_TYPE_IPV4
      && si->type == STATIC_IPV4_GATEWAY
      && IPV4_ADDR_SAME (&nexthop->gate.ipv4, &si->gate.ipv4))
    return 1;
  if (nexthop->type == NEXTHOP_TYPE_IFNAME
      && si->type == STATIC_IPV4_IFNAME
      && strcmp (nexthop->ifname, si->gate.ifname) == 0)
    return 1;
  if (nexthop->type == NEXTHOP_TYPE_BLACKHOLE
      && si->type == STATIC_IPV4_BLACKHOLE)
    return 1;
  return 0;
}

/* Uninstall static route from RIB. */
static void
static_uninstall_ipv4 (struct prefix *p, struct static_ipv4 *si)
{
  struct route_node *rn;
  struct rib *rib;
  struct nexthop *nexthop;
  struct route_table *table;

  /* Lookup table.  */
  table = vrf_table (AFI_IP, SAFI_UNICAST, 0);
  if (! table)
    return;
  
  /* Lookup existing route with type and distance. */
  rn = route_node_lookup (table, p);
  if (! rn)
    return;

  for (rib = rn->info; rib; rib = rib->next)
    if (rib->type == ZEBRA_ROUTE_STATIC && rib->distance == si->distance)
      break;

  if (! rib)
    {
      route_unlock_node (rn);
      return;
    }

  /* Lookup nexthop. */
  for (nexthop = rib->nexthop; nexthop; nexthop = nexthop->next)
    if (static_ipv4_nexthop_same (nexthop, si))
      break;

  /* Can't find nexthop. */
  if (! nexthop)
    {
      route_unlock_node (rn);
      return;
    }
  
  /* Check nexthop. */
  if (rib->nexthop_num == 1)
    {
      rib_queue_add (&zebrad, rn, rib);
      rib_delnode (rn, rib);
    }
  else
    {
      if (CHECK_FLAG (nexthop->flags, NEXTHOP_FLAG_FIB))
        rib_uninstall (rn, rib);
      nexthop_delete (rib, nexthop);
      nexthop_free (nexthop);
      rib_queue_add (&zebrad, rn, NULL);
    }
  /* Unlock node. */
  route_unlock_node (rn);
}

/* Add static route into static route configuration. */
int
static_add_ipv4 (struct prefix *p, struct in_addr *gate, const char *ifname,
		 u_char flags, u_char distance, u_int32_t vrf_id)
{
  u_char type = 0;
  struct route_node *rn;
  struct static_ipv4 *si;
  struct static_ipv4 *pp;
  struct static_ipv4 *cp;
  struct static_ipv4 *update = NULL;
  struct route_table *stable;

  /* Lookup table.  */
  stable = vrf_static_table (AFI_IP, SAFI_UNICAST, vrf_id);
  if (! stable)
    return -1;
  
  /* Lookup static route prefix. */
  rn = route_node_get (stable, p);

  /* Make flags. */
  if (gate)
    type = STATIC_IPV4_GATEWAY;
  else if (ifname)
    type = STATIC_IPV4_IFNAME;
  else
    type = STATIC_IPV4_BLACKHOLE;

  /* Do nothing if there is a same static route.  */
  for (si = rn->info; si; si = si->next)
    {
      if (type == si->type
	  && (! gate || IPV4_ADDR_SAME (gate, &si->gate.ipv4))
	  && (! ifname || strcmp (ifname, si->gate.ifname) == 0))
	{
	  if (distance == si->distance)
	    {
	      route_unlock_node (rn);
	      return 0;
	    }
	  else
	    update = si;
	}
    }

  /* Distance chaged.  */
  if (update)
    static_delete_ipv4 (p, gate, ifname, update->distance, vrf_id);

  /* Make new static route structure. */
  si = XMALLOC (MTYPE_STATIC_IPV4, sizeof (struct static_ipv4));
  memset (si, 0, sizeof (struct static_ipv4));

  si->type = type;
  si->distance = distance;
  si->flags = flags;

  if (gate)
    si->gate.ipv4 = *gate;
  if (ifname)
    si->gate.ifname = XSTRDUP (0, ifname);

  /* Add new static route information to the tree with sort by
     distance value and gateway address. */
  for (pp = NULL, cp = rn->info; cp; pp = cp, cp = cp->next)
    {
      if (si->distance < cp->distance)
	break;
      if (si->distance > cp->distance)
	continue;
      if (si->type == STATIC_IPV4_GATEWAY && cp->type == STATIC_IPV4_GATEWAY)
	{
	  if (ntohl (si->gate.ipv4.s_addr) < ntohl (cp->gate.ipv4.s_addr))
	    break;
	  if (ntohl (si->gate.ipv4.s_addr) > ntohl (cp->gate.ipv4.s_addr))
	    continue;
	}
    }

  /* Make linked list. */
  if (pp)
    pp->next = si;
  else
    rn->info = si;
  if (cp)
    cp->prev = si;
  si->prev = pp;
  si->next = cp;

  /* Install into rib. */
  static_install_ipv4 (p, si);

  return 1;
}

/* Delete static route from static route configuration. */
int
static_delete_ipv4 (struct prefix *p, struct in_addr *gate, const char *ifname,
		    u_char distance, u_int32_t vrf_id)
{
  u_char type = 0;
  struct route_node *rn;
  struct static_ipv4 *si;
  struct route_table *stable;

  /* Lookup table.  */
  stable = vrf_static_table (AFI_IP, SAFI_UNICAST, vrf_id);
  if (! stable)
    return -1;

  /* Lookup static route prefix. */
  rn = route_node_lookup (stable, p);
  if (! rn)
    return 0;

  /* Make flags. */
  if (gate)
    type = STATIC_IPV4_GATEWAY;
  else if (ifname)
    type = STATIC_IPV4_IFNAME;
  else
    type = STATIC_IPV4_BLACKHOLE;

  /* Find same static route is the tree */
  for (si = rn->info; si; si = si->next)
    if (type == si->type
	&& (! gate || IPV4_ADDR_SAME (gate, &si->gate.ipv4))
	&& (! ifname || strcmp (ifname, si->gate.ifname) == 0))
      break;

  /* Can't find static route. */
  if (! si)
    {
      route_unlock_node (rn);
      return 0;
    }

  /* Install into rib. */
  static_uninstall_ipv4 (p, si);

  /* Unlink static route from linked list. */
  if (si->prev)
    si->prev->next = si->next;
  else
    rn->info = si->next;
  if (si->next)
    si->next->prev = si->prev;
  route_unlock_node (rn);
  
  /* Free static route configuration. */
  if (ifname)
    XFREE (0, si->gate.ifname);
  XFREE (MTYPE_STATIC_IPV4, si);

  route_unlock_node (rn);

  return 1;
}


#ifdef HAVE_IPV6
static int
rib_bogus_ipv6 (int type, struct prefix_ipv6 *p,
		struct in6_addr *gate, unsigned int ifindex, int table)
{
  if (type == ZEBRA_ROUTE_CONNECT && IN6_IS_ADDR_UNSPECIFIED (&p->prefix)) {
#if defined (MUSICA) || defined (LINUX)
    /* IN6_IS_ADDR_V4COMPAT(&p->prefix) */
    if (p->prefixlen == 96)
      return 0;
#endif /* MUSICA */
    return 1;
  }
  if (type == ZEBRA_ROUTE_KERNEL && IN6_IS_ADDR_UNSPECIFIED (&p->prefix)
      && p->prefixlen == 96 && gate && IN6_IS_ADDR_UNSPECIFIED (gate))
    {
      kernel_delete_ipv6_old (p, gate, ifindex, 0, table);
      return 1;
    }
  return 0;
}

int
rib_add_ipv6 (int type, int flags, struct prefix_ipv6 *p,
	      struct in6_addr *gate, unsigned int ifindex, u_int32_t vrf_id,
	      u_int32_t metric, u_char distance)
{
  struct rib *rib;
  struct rib *same = NULL;
  struct route_table *table;
  struct route_node *rn;
  struct nexthop *nexthop;

  /* Lookup table.  */
  table = vrf_table (AFI_IP6, SAFI_UNICAST, 0);
  if (! table)
    return 0;

  /* Make sure mask is applied. */
  apply_mask_ipv6 (p);

  /* Set default distance by route type. */
  if (!distance)
    distance = route_info[type].distance;
  
  if (type == ZEBRA_ROUTE_BGP && CHECK_FLAG (flags, ZEBRA_FLAG_IBGP))
    distance = 200;

  /* Filter bogus route. */
  if (rib_bogus_ipv6 (type, p, gate, ifindex, 0))
    return 0;

  /* Lookup route node.*/
  rn = route_node_get (table, (struct prefix *) p);

  /* If same type of route are installed, treat it as a implicit
     withdraw. */
  for (rib = rn->info; rib; rib = rib->next)
    {
      if (rib->type != type)
	continue;
      if (rib->type != ZEBRA_ROUTE_CONNECT)
	{
	  same = rib;
	  break;
	}
      else if ((nexthop = rib->nexthop) &&
	       nexthop->type == NEXTHOP_TYPE_IFINDEX &&
	       nexthop->ifindex == ifindex)
	{
	  rib->refcnt++;
	  return 0;
	}
    }

  /* Allocate new rib structure. */
  rib = XCALLOC (MTYPE_RIB, sizeof (struct rib));
  
  rib->type = type;
  rib->distance = distance;
  rib->flags = flags;
  rib->metric = metric;
  rib->table = vrf_id;
  rib->nexthop_num = 0;
  rib->uptime = time (NULL);

  /* Nexthop settings. */
  if (gate)
    {
      if (ifindex)
	nexthop_ipv6_ifindex_add (rib, gate, ifindex);
      else
	nexthop_ipv6_add (rib, gate);
    }
  else
    nexthop_ifindex_add (rib, ifindex);

  /* If this route is kernel route, set FIB flag to the route. */
  if (type == ZEBRA_ROUTE_KERNEL || type == ZEBRA_ROUTE_CONNECT)
    for (nexthop = rib->nexthop; nexthop; nexthop = nexthop->next)
      SET_FLAG (nexthop->flags, NEXTHOP_FLAG_FIB);

  /* Link new rib to node.*/
  rib_addnode (rn, rib);

  /* Process this route node. */
  rib_queue_add (&zebrad, rn, same);
  
  /* Free implicit route.*/
  if (same)
    rib_delnode (rn, same);
  
  route_unlock_node (rn);
  return 0;
}

/* XXX factor with rib_delete_ipv6 */
int
rib_delete_ipv6 (int type, int flags, struct prefix_ipv6 *p,
		 struct in6_addr *gate, unsigned int ifindex, u_int32_t vrf_id)
{
  struct route_table *table;
  struct route_node *rn;
  struct rib *rib;
  struct rib *fib = NULL;
  struct rib *same = NULL;
  struct nexthop *nexthop;
  char buf1[BUFSIZ];
  char buf2[BUFSIZ];

  /* Apply mask. */
  apply_mask_ipv6 (p);

  /* Lookup table.  */
  table = vrf_table (AFI_IP6, SAFI_UNICAST, 0);
  if (! table)
    return 0;
  
  /* Lookup route node. */
  rn = route_node_lookup (table, (struct prefix *) p);
  if (! rn)
    {
      if (IS_ZEBRA_DEBUG_KERNEL)
	{
	  if (gate)
	    zlog_debug ("route %s/%d via %s ifindex %d doesn't exist in rib",
		       inet_ntop (AF_INET6, &p->prefix, buf1, BUFSIZ),
		       p->prefixlen,
		       inet_ntop (AF_INET6, gate, buf2, BUFSIZ),
		       ifindex);
	  else
	    zlog_debug ("route %s/%d ifindex %d doesn't exist in rib",
		       inet_ntop (AF_INET6, &p->prefix, buf1, BUFSIZ),
		       p->prefixlen,
		       ifindex);
	}
      return ZEBRA_ERR_RTNOEXIST;
    }

  /* Lookup same type route. */
  for (rib = rn->info; rib; rib = rib->next)
    {
      if (CHECK_FLAG (rib->flags, ZEBRA_FLAG_SELECTED))
	fib = rib;

      if (rib->type != type)
        continue;
      if (rib->type == ZEBRA_ROUTE_CONNECT && (nexthop = rib->nexthop) &&
	  nexthop->type == NEXTHOP_TYPE_IFINDEX && nexthop->ifindex == ifindex)
	{
	  if (rib->refcnt)
	    {
	      rib->refcnt--;
	      route_unlock_node (rn);
	      route_unlock_node (rn);
	      return 0;
	    }
	  same = rib;
	  break;
	}
      /* Make sure that the route found has the same gateway. */
      else if (gate == NULL ||
	       ((nexthop = rib->nexthop) &&
	        (IPV6_ADDR_SAME (&nexthop->gate.ipv6, gate) ||
		 IPV6_ADDR_SAME (&nexthop->rgate.ipv6, gate))))
	{
	  same = rib;
	  break;
	}
    }

  /* If same type of route can't be found and this message is from
     kernel. */
  if (! same)
    {
      if (fib && type == ZEBRA_ROUTE_KERNEL)
	{
	  /* Unset flags. */
	  for (nexthop = fib->nexthop; nexthop; nexthop = nexthop->next)
	    UNSET_FLAG (nexthop->flags, NEXTHOP_FLAG_FIB);

	  UNSET_FLAG (fib->flags, ZEBRA_FLAG_SELECTED);
	}
      else
	{
	  if (IS_ZEBRA_DEBUG_KERNEL)
	    {
	      if (gate)
		zlog_debug ("route %s/%d via %s ifindex %d type %d doesn't exist in rib",
			   inet_ntop (AF_INET6, &p->prefix, buf1, BUFSIZ),
			   p->prefixlen,
			   inet_ntop (AF_INET6, gate, buf2, BUFSIZ),
			   ifindex,
			   type);
	      else
		zlog_debug ("route %s/%d ifindex %d type %d doesn't exist in rib",
			   inet_ntop (AF_INET6, &p->prefix, buf1, BUFSIZ),
			   p->prefixlen,
			   ifindex,
			   type);
	    }
	  route_unlock_node (rn);
	  return ZEBRA_ERR_RTNOEXIST;
	}
    }

  /* Process changes. */
  rib_queue_add (&zebrad, rn, same);

  if (same)
    rib_delnode (rn, same);
  
  route_unlock_node (rn);
  return 0;
}

/* Install static route into rib. */
static void
static_install_ipv6 (struct prefix *p, struct static_ipv6 *si)
{
  struct rib *rib;
  struct route_table *table;
  struct route_node *rn;

  /* Lookup table.  */
  table = vrf_table (AFI_IP6, SAFI_UNICAST, 0);
  if (! table)
    return;

  /* Lookup existing route */
  rn = route_node_get (table, p);
  for (rib = rn->info; rib; rib = rib->next)
    if (rib->type == ZEBRA_ROUTE_STATIC && rib->distance == si->distance)
      break;

  if (rib)
    {
      /* Same distance static route is there.  Update it with new
         nexthop. */
      route_unlock_node (rn);

      switch (si->type)
	{
	case STATIC_IPV6_GATEWAY:
	  nexthop_ipv6_add (rib, &si->ipv6);
	  break;
	case STATIC_IPV6_IFNAME:
	  nexthop_ifname_add (rib, si->ifname);
	  break;
	case STATIC_IPV6_GATEWAY_IFNAME:
	  nexthop_ipv6_ifname_add (rib, &si->ipv6, si->ifname);
	  break;
	}
      rib_queue_add (&zebrad, rn, NULL);
    }
  else
    {
      /* This is new static route. */
      rib = XCALLOC (MTYPE_RIB, sizeof (struct rib));
      
      rib->type = ZEBRA_ROUTE_STATIC;
      rib->distance = si->distance;
      rib->metric = 0;
      rib->nexthop_num = 0;

      switch (si->type)
	{
	case STATIC_IPV6_GATEWAY:
	  nexthop_ipv6_add (rib, &si->ipv6);
	  break;
	case STATIC_IPV6_IFNAME:
	  nexthop_ifname_add (rib, si->ifname);
	  break;
	case STATIC_IPV6_GATEWAY_IFNAME:
	  nexthop_ipv6_ifname_add (rib, &si->ipv6, si->ifname);
	  break;
	}

      /* Save the flags of this static routes (reject, blackhole) */
      rib->flags = si->flags;

      /* Link this rib to the tree. */
      rib_addnode (rn, rib);

      /* Process this prefix. */
      rib_queue_add (&zebrad, rn, NULL);
    }
}

static int
static_ipv6_nexthop_same (struct nexthop *nexthop, struct static_ipv6 *si)
{
  if (nexthop->type == NEXTHOP_TYPE_IPV6
      && si->type == STATIC_IPV6_GATEWAY
      && IPV6_ADDR_SAME (&nexthop->gate.ipv6, &si->ipv6))
    return 1;
  if (nexthop->type == NEXTHOP_TYPE_IFNAME
      && si->type == STATIC_IPV6_IFNAME
      && strcmp (nexthop->ifname, si->ifname) == 0)
    return 1;
  if (nexthop->type == NEXTHOP_TYPE_IPV6_IFNAME
      && si->type == STATIC_IPV6_GATEWAY_IFNAME
      && IPV6_ADDR_SAME (&nexthop->gate.ipv6, &si->ipv6)
      && strcmp (nexthop->ifname, si->ifname) == 0)
    return 1;
  return 0;
}

static void
static_uninstall_ipv6 (struct prefix *p, struct static_ipv6 *si)
{
  struct route_table *table;
  struct route_node *rn;
  struct rib *rib;
  struct nexthop *nexthop;

  /* Lookup table.  */
  table = vrf_table (AFI_IP6, SAFI_UNICAST, 0);
  if (! table)
    return;

  /* Lookup existing route with type and distance. */
  rn = route_node_lookup (table, (struct prefix *) p);
  if (! rn)
    return;

  for (rib = rn->info; rib; rib = rib->next)
    if (rib->type == ZEBRA_ROUTE_STATIC && rib->distance == si->distance)
      break;
  if (! rib)
    {
      route_unlock_node (rn);
      return;
    }

  /* Lookup nexthop. */
  for (nexthop = rib->nexthop; nexthop; nexthop = nexthop->next)
    if (static_ipv6_nexthop_same (nexthop, si))
      break;

  /* Can't find nexthop. */
  if (! nexthop)
    {
      route_unlock_node (rn);
      return;
    }
  
  /* Check nexthop. */
  if (rib->nexthop_num == 1)
    {
      rib_delnode (rn, rib);
      rib_queue_add (&zebrad, rn, rib);
    }
  else
    {
      if (CHECK_FLAG (nexthop->flags, NEXTHOP_FLAG_FIB))
        rib_uninstall (rn, rib);
      nexthop_delete (rib, nexthop);
      nexthop_free (nexthop);
      rib_queue_add (&zebrad, rn, NULL);
    }
  /* Unlock node. */
  route_unlock_node (rn);
}

/* Add static route into static route configuration. */
int
static_add_ipv6 (struct prefix *p, u_char type, struct in6_addr *gate,
		 const char *ifname, u_char flags, u_char distance,
		 u_int32_t vrf_id)
{
  struct route_node *rn;
  struct static_ipv6 *si;
  struct static_ipv6 *pp;
  struct static_ipv6 *cp;
  struct route_table *stable;

  /* Lookup table.  */
  stable = vrf_static_table (AFI_IP6, SAFI_UNICAST, vrf_id);
  if (! stable)
    return -1;

  /* Lookup static route prefix. */
  rn = route_node_get (stable, p);

  /* Do nothing if there is a same static route.  */
  for (si = rn->info; si; si = si->next)
    {
      if (distance == si->distance 
	  && type == si->type
	  && (! gate || IPV6_ADDR_SAME (gate, &si->ipv6))
	  && (! ifname || strcmp (ifname, si->ifname) == 0))
	{
	  route_unlock_node (rn);
	  return 0;
	}
    }

  /* Make new static route structure. */
  si = XMALLOC (MTYPE_STATIC_IPV6, sizeof (struct static_ipv6));
  memset (si, 0, sizeof (struct static_ipv6));

  si->type = type;
  si->distance = distance;
  si->flags = flags;

  switch (type)
    {
    case STATIC_IPV6_GATEWAY:
      si->ipv6 = *gate;
      break;
    case STATIC_IPV6_IFNAME:
      si->ifname = XSTRDUP (0, ifname);
      break;
    case STATIC_IPV6_GATEWAY_IFNAME:
      si->ipv6 = *gate;
      si->ifname = XSTRDUP (0, ifname);
      break;
    }

  /* Add new static route information to the tree with sort by
     distance value and gateway address. */
  for (pp = NULL, cp = rn->info; cp; pp = cp, cp = cp->next)
    {
      if (si->distance < cp->distance)
	break;
      if (si->distance > cp->distance)
	continue;
    }

  /* Make linked list. */
  if (pp)
    pp->next = si;
  else
    rn->info = si;
  if (cp)
    cp->prev = si;
  si->prev = pp;
  si->next = cp;

  /* Install into rib. */
  static_install_ipv6 (p, si);

  return 1;
}

/* Delete static route from static route configuration. */
int
static_delete_ipv6 (struct prefix *p, u_char type, struct in6_addr *gate,
		    const char *ifname, u_char distance, u_int32_t vrf_id)
{
  struct route_node *rn;
  struct static_ipv6 *si;
  struct route_table *stable;

  /* Lookup table.  */
  stable = vrf_static_table (AFI_IP6, SAFI_UNICAST, vrf_id);
  if (! stable)
    return -1;

  /* Lookup static route prefix. */
  rn = route_node_lookup (stable, p);
  if (! rn)
    return 0;

  /* Find same static route is the tree */
  for (si = rn->info; si; si = si->next)
    if (distance == si->distance 
	&& type == si->type
	&& (! gate || IPV6_ADDR_SAME (gate, &si->ipv6))
	&& (! ifname || strcmp (ifname, si->ifname) == 0))
      break;

  /* Can't find static route. */
  if (! si)
    {
      route_unlock_node (rn);
      return 0;
    }

  /* Install into rib. */
  static_uninstall_ipv6 (p, si);

  /* Unlink static route from linked list. */
  if (si->prev)
    si->prev->next = si->next;
  else
    rn->info = si->next;
  if (si->next)
    si->next->prev = si->prev;
  
  /* Free static route configuration. */
  if (ifname)
    XFREE (0, si->ifname);
  XFREE (MTYPE_STATIC_IPV6, si);

  return 1;
}
#endif /* HAVE_IPV6 */

/* RIB update function. */
void
rib_update (void)
{
  struct route_node *rn;
  struct route_table *table;
  
  table = vrf_table (AFI_IP, SAFI_UNICAST, 0);
  if (table)
    for (rn = route_top (table); rn; rn = route_next (rn))
      if (rn->info)
        rib_queue_add (&zebrad, rn, NULL);

  table = vrf_table (AFI_IP6, SAFI_UNICAST, 0);
  if (table)
    for (rn = route_top (table); rn; rn = route_next (rn))
      if (rn->info)
        rib_queue_add (&zebrad, rn, NULL);
}

/* Interface goes up. */
static void
rib_if_up (struct interface *ifp)
{
  rib_update ();
}

/* Interface goes down. */
static void
rib_if_down (struct interface *ifp)
{
  rib_update ();
}

/* Remove all routes which comes from non main table.  */
static void
rib_weed_table (struct route_table *table)
{
  struct route_node *rn;
  struct rib *rib;
  struct rib *next;

  if (table)
    for (rn = route_top (table); rn; rn = route_next (rn))
      for (rib = rn->info; rib; rib = next)
	{
	  next = rib->next;

	  if (rib->table != zebrad.rtm_table_default &&
	      rib->table != RT_TABLE_MAIN)
            rib_delnode (rn, rib);
	}
}

/* Delete all routes from non main table. */
void
rib_weed_tables (void)
{
  rib_weed_table (vrf_table (AFI_IP, SAFI_UNICAST, 0));
  rib_weed_table (vrf_table (AFI_IP6, SAFI_UNICAST, 0));
}

/* Delete self installed routes after zebra is relaunched.  */
static void
rib_sweep_table (struct route_table *table)
{
  struct route_node *rn;
  struct rib *rib;
  struct rib *next;
  int ret = 0;

  if (table)
    for (rn = route_top (table); rn; rn = route_next (rn))
      for (rib = rn->info; rib; rib = next)
	{
	  next = rib->next;

	  if (rib->type == ZEBRA_ROUTE_KERNEL && 
	      CHECK_FLAG (rib->flags, ZEBRA_FLAG_SELFROUTE))
	    {
	      ret = rib_uninstall_kernel (rn, rib);
	      if (! ret)
                rib_delnode (rn, rib);
	    }
	}
}

/* Sweep all RIB tables.  */
void
rib_sweep_route (void)
{
  rib_sweep_table (vrf_table (AFI_IP, SAFI_UNICAST, 0));
  rib_sweep_table (vrf_table (AFI_IP6, SAFI_UNICAST, 0));
}

/* Close RIB and clean up kernel routes. */
static void
rib_close_table (struct route_table *table)
{
  struct route_node *rn;
  struct rib *rib;

  if (table)
    for (rn = route_top (table); rn; rn = route_next (rn))
      for (rib = rn->info; rib; rib = rib->next)
	if (! RIB_SYSTEM_ROUTE (rib)
	    && CHECK_FLAG (rib->flags, ZEBRA_FLAG_SELECTED))
	  rib_uninstall_kernel (rn, rib);
}

/* Close all RIB tables.  */
void
rib_close (void)
{
  rib_close_table (vrf_table (AFI_IP, SAFI_UNICAST, 0));
  rib_close_table (vrf_table (AFI_IP6, SAFI_UNICAST, 0));
}

/* Routing information base initialize. */
void
rib_init (void)
{
  rib_queue_init (&zebrad);
  /* VRF initialization.  */
  vrf_init ();
}