diff --git a/ospfd/ospf_interface.c b/ospfd/ospf_interface.c
new file mode 100644
index 0000000..ddae980
--- /dev/null
+++ b/ospfd/ospf_interface.c
@@ -0,0 +1,1045 @@
+/*
+ * OSPF Interface functions.
+ * Copyright (C) 1999, 2000 Toshiaki Takada
+ *
+ * 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 "thread.h"
+#include "linklist.h"
+#include "prefix.h"
+#include "if.h"
+#include "table.h"
+#include "memory.h"
+#include "command.h"
+#include "stream.h"
+#include "log.h"
+
+#include "ospfd/ospf_spf.h"
+#include "ospfd/ospf_interface.h"
+#include "ospfd/ospf_ism.h"
+#include "ospfd/ospf_asbr.h"
+#include "ospfd/ospf_lsa.h"
+#include "ospfd/ospf_lsdb.h"
+#include "ospfd/ospf_neighbor.h"
+#include "ospfd/ospf_nsm.h"
+#include "ospfd/ospf_packet.h"
+#include "ospfd/ospf_abr.h"
+#include "ospfd/ospfd.h"
+#include "ospfd/ospf_network.h"
+#include "ospfd/ospf_dump.h"
+#ifdef HAVE_SNMP
+#include "ospfd/ospf_snmp.h"
+#endif /* HAVE_SNMP */
+
+
+int
+ospf_if_get_output_cost (struct ospf_interface *oi)
+{
+  /* If all else fails, use default OSPF cost */
+  u_int32_t cost;
+  u_int32_t bw, refbw;
+
+  bw = oi->ifp->bandwidth ? oi->ifp->bandwidth : OSPF_DEFAULT_BANDWIDTH;
+  refbw = ospf_top ? ospf_top->ref_bandwidth : OSPF_DEFAULT_REF_BANDWIDTH;
+
+  /* A specifed ip ospf cost overrides a calculated one. */
+  if (OSPF_IF_PARAM_CONFIGURED (IF_DEF_PARAMS (oi->ifp), output_cost_cmd) ||
+      OSPF_IF_PARAM_CONFIGURED (oi->params, output_cost_cmd))
+    cost = OSPF_IF_PARAM (oi, output_cost_cmd);
+  /* See if a cost can be calculated from the zebra processes
+     interface bandwidth field. */
+  else
+    {
+      cost = (u_int32_t) ((double)refbw / (double)bw + (double)0.5);
+      if (cost < 1)
+	cost = 1;
+      else if (cost > 65535)
+	cost = 65535;
+    }
+
+  return cost;
+}
+
+void
+ospf_if_recalculate_output_cost (struct interface *ifp)
+{
+  u_int32_t newcost;
+  struct route_node *rn;
+  
+  for (rn = route_top (IF_OIFS (ifp)); rn; rn = route_next (rn))
+    {
+      struct ospf_interface *oi;
+      
+      if ( (oi = rn->info) == NULL)
+	continue;
+
+      newcost = ospf_if_get_output_cost (oi);
+
+      /* Is actual output cost changed? */
+      if (oi->output_cost != newcost)
+	{
+	  oi->output_cost = newcost;
+	  ospf_router_lsa_timer_add (oi->area);
+	}
+    }
+}
+
+void
+ospf_if_reset_variables (struct ospf_interface *oi)
+{
+  /* Set default values. */
+  /* don't clear this flag.  oi->flag = OSPF_IF_DISABLE; */
+
+  if (oi->vl_data)
+    oi->type = OSPF_IFTYPE_VIRTUALLINK;
+  else 
+  /* preserve network-type */
+  if (oi->type != OSPF_IFTYPE_NBMA)
+    oi->type = OSPF_IFTYPE_BROADCAST;
+
+  oi->state = ISM_Down;
+
+  oi->crypt_seqnum = 0;
+
+  /* This must be short, (less than RxmtInterval) 
+     - RFC 2328 Section 13.5 para 3.  Set to 1 second to avoid Acks being
+       held back for too long - MAG */
+  oi->v_ls_ack = 1;  
+}
+
+void
+ospf_add_to_if (struct interface *ifp, struct ospf_interface *oi)
+{
+  struct route_node *rn;
+  struct prefix p;
+
+  p = *oi->address;
+  p.prefixlen = IPV4_MAX_PREFIXLEN;
+
+  rn = route_node_get (IF_OIFS (ifp), &p);
+  assert (! rn->info);
+  rn->info = oi;
+}
+
+void
+ospf_delete_from_if (struct interface *ifp, struct ospf_interface *oi)
+{
+  struct route_node *rn;
+  struct prefix p;
+
+  p = *oi->address;
+  p.prefixlen = IPV4_MAX_PREFIXLEN;
+
+  rn = route_node_lookup (IF_OIFS (oi->ifp), &p);
+  assert (rn);
+  assert (rn->info);
+  rn->info = NULL;
+  route_unlock_node (rn);
+  route_unlock_node (rn);
+}
+
+struct ospf_interface *
+ospf_if_new (struct interface *ifp, struct prefix *p)
+{
+  struct ospf_interface *oi;
+
+  oi = XCALLOC (MTYPE_OSPF_IF, sizeof (struct ospf_interface));
+  memset (oi, 0, sizeof (struct ospf_interface));
+
+  /* Set zebra interface pointer. */
+  oi->ifp = ifp;
+  oi->address = p;
+  
+  ospf_add_to_if (ifp, oi);
+  listnode_add (ospf_top->oiflist, oi);
+  
+  /* Clear self-originated network-LSA. */
+  oi->network_lsa_self = NULL;
+
+  /* Initialize neighbor list. */
+  oi->nbrs = route_table_init ();
+
+  /* Initialize static neighbor list. */
+  oi->nbr_nbma = list_new ();
+
+  /* Initialize Link State Acknowledgment list. */
+  oi->ls_ack = list_new ();
+  oi->ls_ack_direct.ls_ack = list_new ();
+
+  /* Set default values. */
+  ospf_if_reset_variables (oi);
+
+  /* Add pseudo neighbor. */
+  oi->nbr_self = ospf_nbr_new (oi);
+  oi->nbr_self->state = NSM_TwoWay;
+  /*  oi->nbr_self->router_id = ospf_top->router_id; */
+  oi->nbr_self->priority = OSPF_IF_PARAM (oi, priority);
+  oi->nbr_self->options = OSPF_OPTION_E;
+
+  oi->ls_upd_queue = route_table_init ();
+  oi->t_ls_upd_event = NULL;
+  oi->t_ls_ack_direct = NULL;
+
+#ifdef HAVE_OPAQUE_LSA
+  ospf_opaque_type9_lsa_init (oi);
+#endif /* HAVE_OPAQUE_LSA */
+
+  oi->ospf = ospf_top;
+  
+  return oi;
+}
+
+/* Restore an interface to its pre UP state
+   Used from ism_interface_down only */
+void
+ospf_if_cleanup (struct ospf_interface *oi)
+{
+  struct route_node *rn;
+  listnode node;
+  struct ospf_neighbor *nbr;
+
+  /* oi->nbrs and oi->nbr_nbma should be deletete on InterafceDown event */
+  /* delete all static neighbors attached to this interface */
+  for (node = listhead (oi->nbr_nbma); node; )
+    {
+      struct ospf_nbr_nbma *nbr_nbma = getdata (node);
+      nextnode (node);
+
+      OSPF_POLL_TIMER_OFF (nbr_nbma->t_poll);
+
+      if (nbr_nbma->nbr)
+	{
+	  nbr_nbma->nbr->nbr_nbma = NULL;
+	  nbr_nbma->nbr = NULL;
+	}
+
+      nbr_nbma->oi = NULL;
+      
+      listnode_delete (oi->nbr_nbma, nbr_nbma);
+    }
+
+  /* send Neighbor event KillNbr to all associated neighbors. */
+  for (rn = route_top (oi->nbrs); rn; rn = route_next (rn))
+    if ((nbr = rn->info) != NULL)
+      if (nbr != oi->nbr_self)
+	OSPF_NSM_EVENT_EXECUTE (nbr, NSM_KillNbr);
+
+  /* Cleanup Link State Acknowlegdment list. */
+  for (node = listhead (oi->ls_ack); node; nextnode (node))
+    ospf_lsa_unlock (node->data);
+  list_delete_all_node (oi->ls_ack);
+
+  oi->crypt_seqnum = 0;
+  
+  /* Empty link state update queue */
+  ospf_ls_upd_queue_empty (oi);
+  
+ /* Handle pseudo neighbor. */
+  ospf_nbr_delete (oi->nbr_self);
+  oi->nbr_self = ospf_nbr_new (oi);
+  oi->nbr_self->state = NSM_TwoWay;
+  oi->nbr_self->priority = OSPF_IF_PARAM (oi, priority);
+  oi->nbr_self->options = OSPF_OPTION_E;
+
+  ospf_lsa_unlock (oi->network_lsa_self);
+  oi->network_lsa_self = NULL;
+  OSPF_TIMER_OFF (oi->t_network_lsa_self);
+}
+
+void
+ospf_if_free (struct ospf_interface *oi)
+{
+  ospf_if_down (oi);
+
+  assert (oi->state == ISM_Down);
+
+#ifdef HAVE_OPAQUE_LSA
+  ospf_opaque_type9_lsa_term (oi);
+#endif /* HAVE_OPAQUE_LSA */
+
+  /* Free Pseudo Neighbour */
+  ospf_nbr_delete (oi->nbr_self);
+  
+  route_table_finish (oi->nbrs);
+  route_table_finish (oi->ls_upd_queue);
+  
+  /* Free any lists that should be freed */
+  list_free (oi->nbr_nbma);
+  
+  list_free (oi->ls_ack);
+  list_free (oi->ls_ack_direct.ls_ack);
+  
+  ospf_delete_from_if (oi->ifp, oi);
+
+  listnode_delete (ospf_top->oiflist, oi);
+  listnode_delete (oi->area->oiflist, oi);
+
+  memset (oi, 0, sizeof (*oi));
+  XFREE (MTYPE_OSPF_IF, oi);
+}
+
+
+/*
+*  check if interface with given address is configured and
+*  return it if yes.
+*/
+struct ospf_interface *
+ospf_if_is_configured (struct in_addr *address)
+{
+  listnode node;
+  struct ospf_interface *oi;
+  struct prefix *addr;
+  
+  for (node = listhead (ospf_top->oiflist); node; nextnode (node))
+    if ((oi = getdata (node)) != NULL && oi->type != OSPF_IFTYPE_VIRTUALLINK)
+      {
+	if (oi->type == OSPF_IFTYPE_POINTOPOINT)
+	  addr = oi->connected->destination;
+	else
+	  addr = oi->address;
+	
+	if (IPV4_ADDR_SAME (address, &addr->u.prefix4))
+	  return oi;
+      }
+
+  return NULL;
+}
+
+int
+ospf_if_is_up (struct ospf_interface *oi)
+{
+  return if_is_up (oi->ifp);
+}
+
+struct ospf_interface *
+ospf_if_lookup_by_local_addr (struct interface *ifp, struct in_addr address)
+{
+  listnode node;
+  struct ospf_interface *oi;
+  
+  for (node = listhead (ospf_top->oiflist); node; nextnode (node))
+    if ((oi = getdata (node)) != NULL && oi->type != OSPF_IFTYPE_VIRTUALLINK)
+      {
+	if (ifp && oi->ifp != ifp)
+	  continue;
+	
+	if (IPV4_ADDR_SAME (&address, &oi->address->u.prefix4))
+	  return oi;
+      }
+
+  return NULL;
+}
+
+struct ospf_interface *
+ospf_if_lookup_by_prefix (struct prefix_ipv4 *p)
+{
+  listnode node;
+  struct ospf_interface *oi;
+  struct prefix ptmp;
+  
+  /* Check each Interface. */
+  for (node = listhead (ospf_top->oiflist); node; nextnode (node)) {
+    if ((oi = getdata (node)) != NULL && oi->type != OSPF_IFTYPE_VIRTUALLINK)
+      {
+	if (oi->type == OSPF_IFTYPE_POINTOPOINT) {
+	  prefix_copy (&ptmp, oi->connected->destination);
+	  ptmp.prefixlen = IPV4_MAX_BITLEN;
+	}
+	else
+	  prefix_copy (&ptmp, oi->address);
+	
+	apply_mask (&ptmp);
+	if (prefix_same (&ptmp, (struct prefix *) p))
+	  return oi;
+      }
+  }
+  return NULL;
+}
+
+/* determine receiving interface by source of packet */
+struct ospf_interface *
+ospf_if_lookup_recv_interface (struct in_addr src)
+{
+  listnode node;
+  struct prefix_ipv4 addr;
+  struct ospf_interface *oi, *match;
+
+  addr.family = AF_INET;
+  addr.prefix = src;
+  addr.prefixlen = IPV4_MAX_BITLEN;
+
+  match = NULL;
+
+  for (node = listhead (ospf_top->oiflist); node; nextnode (node))
+    {
+      oi = getdata (node);
+      
+      if (oi->type == OSPF_IFTYPE_VIRTUALLINK)
+	continue;
+      
+      if (oi->type == OSPF_IFTYPE_POINTOPOINT)
+	{
+	  if (IPV4_ADDR_SAME (&oi->connected->destination->u.prefix4, &src))
+	    return oi;
+	}
+      else
+	{
+	  if (prefix_match (oi->address, (struct prefix *) &addr))
+	    match = oi;
+	}
+    }
+
+  return match;
+}
+
+void
+ospf_if_stream_set (struct ospf_interface *oi)
+{
+  /* set output fifo queue. */
+  if (oi->obuf == NULL) 
+    oi->obuf = ospf_fifo_new ();
+}
+
+void
+ospf_if_stream_unset (struct ospf_interface *oi)
+{
+  if (oi->obuf)
+    {
+     ospf_fifo_free (oi->obuf);
+     oi->obuf = NULL;
+
+     if (oi->on_write_q)
+       {
+	 listnode_delete (ospf_top->oi_write_q, oi);
+         if (list_isempty(ospf_top->oi_write_q))
+           OSPF_TIMER_OFF (ospf_top->t_write);
+	 oi->on_write_q = 0;
+       }
+    }
+}
+
+struct ospf_if_params *
+ospf_new_if_params ()
+{
+  struct ospf_if_params *oip;
+
+  oip = XMALLOC (MTYPE_OSPF_IF_PARAMS, sizeof (struct ospf_if_params));
+  memset (oip, 0, sizeof (struct ospf_if_params));
+
+  if (!oip)
+    return NULL;
+
+  memset (oip, 0, sizeof (struct ospf_if_params));
+
+  UNSET_IF_PARAM (oip, output_cost_cmd);
+  UNSET_IF_PARAM (oip, transmit_delay);
+  UNSET_IF_PARAM (oip, retransmit_interval);
+  UNSET_IF_PARAM (oip, passive_interface);
+  UNSET_IF_PARAM (oip, v_hello);
+  UNSET_IF_PARAM (oip, v_wait);
+  UNSET_IF_PARAM (oip, priority);
+  UNSET_IF_PARAM (oip, type);
+  UNSET_IF_PARAM (oip, auth_simple);
+  UNSET_IF_PARAM (oip, auth_crypt);
+  UNSET_IF_PARAM (oip, auth_type);
+  
+  oip->auth_crypt = list_new ();
+
+  return oip;
+}
+
+void
+ospf_del_if_params (struct ospf_if_params *oip)
+{
+  list_delete (oip->auth_crypt);
+  XFREE (MTYPE_OSPF_IF_PARAMS, oip);
+}
+
+void
+ospf_free_if_params (struct interface *ifp, struct in_addr addr)
+{
+  struct ospf_if_params *oip;
+  struct prefix_ipv4 p;
+  struct route_node *rn;
+  p.prefixlen = IPV4_MAX_PREFIXLEN;
+  p.prefix = addr;
+  rn = route_node_lookup (IF_OIFS_PARAMS (ifp), (struct prefix*)&p);
+  if (!rn || !rn->info)
+    return;
+
+  oip = rn->info;
+  route_unlock_node (rn);
+  
+  if (!OSPF_IF_PARAM_CONFIGURED (oip, output_cost_cmd) &&
+      !OSPF_IF_PARAM_CONFIGURED (oip, transmit_delay) &&
+      !OSPF_IF_PARAM_CONFIGURED (oip, retransmit_interval) &&
+      !OSPF_IF_PARAM_CONFIGURED (oip, passive_interface) &&
+      !OSPF_IF_PARAM_CONFIGURED (oip, v_hello) &&
+      !OSPF_IF_PARAM_CONFIGURED (oip, v_wait) &&
+      !OSPF_IF_PARAM_CONFIGURED (oip, priority) &&
+      !OSPF_IF_PARAM_CONFIGURED (oip, type) &&
+      !OSPF_IF_PARAM_CONFIGURED (oip, auth_simple) &&
+      !OSPF_IF_PARAM_CONFIGURED (oip, auth_type) &&
+      listcount (oip->auth_crypt) == 0)
+    {
+      ospf_del_if_params (oip);
+      rn->info = NULL;
+      route_unlock_node (rn);
+    }
+}
+
+struct ospf_if_params *
+ospf_lookup_if_params (struct interface *ifp, struct in_addr addr)
+{
+  struct prefix_ipv4 p;
+  struct route_node *rn;
+
+  p.prefixlen = IPV4_MAX_PREFIXLEN;
+  p.prefix = addr;
+
+  rn = route_node_lookup (IF_OIFS_PARAMS (ifp), (struct prefix*)&p);
+  
+  if (rn)
+    {
+      route_unlock_node (rn);
+      return rn->info;
+    }
+
+  return NULL;
+}
+
+struct ospf_if_params *
+ospf_get_if_params (struct interface *ifp, struct in_addr addr)
+{
+  struct prefix_ipv4 p;
+  struct route_node *rn;
+
+  p.family = AF_INET;
+  p.prefixlen = IPV4_MAX_PREFIXLEN;
+  p.prefix = addr;
+
+  rn = route_node_get (IF_OIFS_PARAMS (ifp), (struct prefix*)&p);
+  
+  if (rn->info == NULL)
+    rn->info = ospf_new_if_params ();
+  else
+    route_unlock_node (rn);
+  
+  return rn->info;
+}
+
+void
+ospf_if_update_params (struct interface *ifp, struct in_addr addr)
+{
+  struct route_node *rn;
+  struct ospf_interface *oi;
+  
+  for (rn = route_top (IF_OIFS (ifp)); rn; rn = route_next (rn))
+    {
+      if ((oi = rn->info) == NULL)
+	continue;
+
+      if (IPV4_ADDR_SAME (&oi->address->u.prefix4, &addr))
+	oi->params = ospf_lookup_if_params (ifp, oi->address->u.prefix4);
+    }
+}
+
+int
+ospf_if_new_hook (struct interface *ifp)
+{
+  int rc = 0;
+
+  ifp->info = XMALLOC (MTYPE_OSPF_IF_INFO, sizeof (struct ospf_if_info));
+  memset (ifp->info, 0, sizeof (struct ospf_if_info));
+  
+  IF_OIFS (ifp) = route_table_init ();
+  IF_OIFS_PARAMS (ifp) = route_table_init ();
+  
+  IF_DEF_PARAMS (ifp) = ospf_new_if_params ();
+  
+  SET_IF_PARAM (IF_DEF_PARAMS (ifp), transmit_delay);
+  IF_DEF_PARAMS (ifp)->transmit_delay = OSPF_TRANSMIT_DELAY_DEFAULT;
+  
+  SET_IF_PARAM (IF_DEF_PARAMS (ifp), retransmit_interval);
+  IF_DEF_PARAMS (ifp)->retransmit_interval = OSPF_RETRANSMIT_INTERVAL_DEFAULT;
+
+  SET_IF_PARAM (IF_DEF_PARAMS (ifp), priority);
+  IF_DEF_PARAMS (ifp)->priority = OSPF_ROUTER_PRIORITY_DEFAULT;
+
+  SET_IF_PARAM (IF_DEF_PARAMS (ifp), passive_interface);
+  IF_DEF_PARAMS (ifp)->passive_interface = OSPF_IF_ACTIVE;
+
+  SET_IF_PARAM (IF_DEF_PARAMS (ifp), v_hello);
+  IF_DEF_PARAMS (ifp)->v_hello = OSPF_HELLO_INTERVAL_DEFAULT;
+
+  SET_IF_PARAM (IF_DEF_PARAMS (ifp), v_wait);
+  IF_DEF_PARAMS (ifp)->v_wait = OSPF_ROUTER_DEAD_INTERVAL_DEFAULT;
+
+  SET_IF_PARAM (IF_DEF_PARAMS (ifp), auth_simple);
+  memset (IF_DEF_PARAMS (ifp)->auth_simple, 0, OSPF_AUTH_SIMPLE_SIZE);
+  
+  SET_IF_PARAM (IF_DEF_PARAMS (ifp), auth_crypt);
+  IF_DEF_PARAMS (ifp)->auth_crypt = list_new ();
+
+  SET_IF_PARAM (IF_DEF_PARAMS (ifp), auth_type);
+  IF_DEF_PARAMS (ifp)->auth_type = OSPF_AUTH_NOTSET;
+  
+#ifdef HAVE_OPAQUE_LSA
+  rc = ospf_opaque_new_if (ifp);
+#endif /* HAVE_OPAQUE_LSA */
+  return rc;
+}
+
+int
+ospf_if_delete_hook (struct interface *ifp)
+{
+  int rc = 0;
+#ifdef HAVE_OPAQUE_LSA
+  rc = ospf_opaque_del_if (ifp);
+#endif /* HAVE_OPAQUE_LSA */
+  route_table_finish (IF_OIFS (ifp));
+  route_table_finish (IF_OIFS_PARAMS (ifp));
+  XFREE (MTYPE_OSPF_IF_INFO, ifp->info);
+  ifp->info = NULL;
+
+  return rc;
+}
+
+int
+ospf_if_is_enable (struct ospf_interface *oi)
+{
+  if (!if_is_loopback (oi->ifp))
+    if (if_is_up (oi->ifp))
+	return 1;
+
+  return 0;
+}
+
+int
+ospf_if_up (struct ospf_interface *oi)
+{
+  if (oi == NULL)
+    return 0;
+
+  if (oi->type == OSPF_IFTYPE_LOOPBACK)
+    OSPF_ISM_EVENT_SCHEDULE (oi, ISM_LoopInd);
+  else
+    {
+      if (oi->type != OSPF_IFTYPE_VIRTUALLINK)
+	ospf_if_add_allspfrouters (ospf_top, oi->address, oi->ifp->ifindex);
+      ospf_if_stream_set (oi);
+      OSPF_ISM_EVENT_SCHEDULE (oi, ISM_InterfaceUp);
+    }
+
+  return 1;
+}
+
+int
+ospf_if_down (struct ospf_interface *oi)
+{
+  if (oi == NULL)
+    return 0;
+
+  OSPF_ISM_EVENT_EXECUTE (oi, ISM_InterfaceDown);
+  /* Shutdown packet reception and sending */
+  ospf_if_stream_unset (oi);
+  if (oi->type != OSPF_IFTYPE_VIRTUALLINK)
+    ospf_if_drop_allspfrouters (ospf_top, oi->address, oi->ifp->ifindex);
+
+
+  return 1;
+}
+
+
+/* Virtual Link related functions. */
+
+struct ospf_vl_data *
+ospf_vl_data_new (struct ospf_area *area, struct in_addr vl_peer)
+{
+  struct ospf_vl_data *vl_data;
+
+  vl_data = XMALLOC (MTYPE_OSPF_VL_DATA, sizeof (struct ospf_vl_data));
+  memset (vl_data, 0, sizeof (struct ospf_vl_data));
+
+  vl_data->vl_peer.s_addr = vl_peer.s_addr;
+  vl_data->vl_area_id = area->area_id;
+  vl_data->format = area->format;
+
+  return vl_data;
+}
+
+void
+ospf_vl_data_free (struct ospf_vl_data *vl_data)
+{
+  XFREE (MTYPE_OSPF_VL_DATA, vl_data);
+}
+
+u_int vlink_count = 0;
+
+struct ospf_interface * 
+ospf_vl_new (struct ospf_vl_data *vl_data)
+{
+  struct ospf_interface * voi;
+  struct interface * vi;
+  char   ifname[INTERFACE_NAMSIZ + 1];
+  struct ospf_area *area;
+  struct in_addr area_id;
+  struct connected *co;
+  struct prefix_ipv4 *p;
+  
+  if (IS_DEBUG_OSPF_EVENT)
+    zlog_info ("ospf_vl_new(): Start");
+  if (vlink_count == OSPF_VL_MAX_COUNT)
+    {
+      if (IS_DEBUG_OSPF_EVENT)
+	zlog_info ("ospf_vl_new(): Alarm: "
+		   "cannot create more than OSPF_MAX_VL_COUNT virtual links");
+      return NULL;
+    }
+
+  if (IS_DEBUG_OSPF_EVENT)
+    zlog_info ("ospf_vl_new(): creating pseudo zebra interface");
+
+  vi = if_create ();
+  co = connected_new ();
+  co->ifp = vi;
+  listnode_add (vi->connected, co);
+
+  p = prefix_ipv4_new ();
+  p->family = AF_INET;
+  p->prefix.s_addr = 0;
+  p->prefixlen = 0;
+ 
+  co->address = (struct prefix *)p;
+  
+  voi = ospf_if_new (vi, co->address);
+  if (voi == NULL)
+    {
+      if (IS_DEBUG_OSPF_EVENT)
+	zlog_info ("ospf_vl_new(): Alarm: OSPF int structure is not created");
+      return NULL;
+    }
+  voi->connected = co;
+  voi->vl_data = vl_data;
+  voi->ifp->mtu = OSPF_VL_MTU;
+  voi->type = OSPF_IFTYPE_VIRTUALLINK;
+
+  sprintf (ifname, "VLINK%d", vlink_count++);
+  if (IS_DEBUG_OSPF_EVENT)
+    zlog_info ("ospf_vl_new(): Created name: %s", ifname);
+  strncpy (vi->name, ifname, IFNAMSIZ);
+  if (IS_DEBUG_OSPF_EVENT)
+    zlog_info ("ospf_vl_new(): set if->name to %s", vi->name);
+
+  area_id.s_addr = 0;
+  area = ospf_area_get (area_id, OSPF_AREA_ID_FORMAT_ADDRESS);
+  voi->area = area;
+
+  if (IS_DEBUG_OSPF_EVENT)
+    zlog_info ("ospf_vl_new(): set associated area to the backbone");
+
+  ospf_area_add_if (voi->area, voi);
+
+  ospf_if_stream_set (voi);
+
+  if (IS_DEBUG_OSPF_EVENT)
+    zlog_info ("ospf_vl_new(): Stop");
+  return voi;
+}
+
+void
+ospf_vl_if_delete (struct ospf_vl_data *vl_data)
+{
+  struct interface *ifp = vl_data->vl_oi->ifp;
+  vl_data->vl_oi->address->u.prefix4.s_addr = 0;
+  vl_data->vl_oi->address->prefixlen = 0;
+  ospf_if_free (vl_data->vl_oi);
+  if_delete (ifp);
+  vlink_count--;
+}
+
+struct ospf_vl_data *
+ospf_vl_lookup (struct ospf_area *area, struct in_addr vl_peer)
+{
+  struct ospf_vl_data *vl_data;
+  listnode node;
+
+  for (node = listhead (ospf_top->vlinks); node; nextnode (node))
+    if ((vl_data = getdata (node)) != NULL)
+      if (vl_data->vl_peer.s_addr == vl_peer.s_addr &&
+          IPV4_ADDR_SAME (&vl_data->vl_area_id, &area->area_id))
+        return vl_data;
+
+  return NULL;
+}
+
+void 
+ospf_vl_shutdown (struct ospf_vl_data *vl_data)
+{
+  struct ospf_interface *oi;
+
+  if ((oi = vl_data->vl_oi) == NULL)
+    return;
+
+  oi->address->u.prefix4.s_addr = 0;
+  oi->address->prefixlen = 0;
+
+  UNSET_FLAG (oi->ifp->flags, IFF_UP);
+  /* OSPF_ISM_EVENT_SCHEDULE (oi, ISM_InterfaceDown); */
+  OSPF_ISM_EVENT_EXECUTE (oi, ISM_InterfaceDown);
+}
+
+void
+ospf_vl_add (struct ospf_vl_data *vl_data)
+{
+  listnode_add (ospf_top->vlinks, vl_data);
+#ifdef HAVE_SNMP
+  ospf_snmp_vl_add (vl_data);
+#endif /* HAVE_SNMP */
+}
+
+void
+ospf_vl_delete (struct ospf_vl_data *vl_data)
+{
+  ospf_vl_shutdown (vl_data);
+  ospf_vl_if_delete (vl_data);
+
+#ifdef HAVE_SNMP
+  ospf_snmp_vl_delete (vl_data);
+#endif /* HAVE_SNMP */
+  listnode_delete (ospf_top->vlinks, vl_data);
+
+  ospf_vl_data_free (vl_data);
+}
+
+void
+ospf_vl_set_params (struct ospf_vl_data *vl_data, struct vertex *v)
+{
+  int changed = 0;
+  struct ospf_interface *voi;
+  listnode node;
+  struct vertex_nexthop *nh;
+  int i;
+  struct router_lsa *rl;
+
+  voi = vl_data->vl_oi;
+
+  if (voi->output_cost != v->distance)
+    {
+      voi->output_cost = v->distance;
+      changed = 1;
+    }
+
+  for (node = listhead (v->nexthop); node; nextnode (node))
+    if ((nh = getdata (node)) != NULL)
+      {
+	vl_data->out_oi = (struct ospf_interface *) nh->oi;
+
+	voi->address->u.prefix4 = vl_data->out_oi->address->u.prefix4;
+	voi->address->prefixlen = vl_data->out_oi->address->prefixlen;
+
+	break; /* We take the first interface. */
+      }
+
+  rl = (struct router_lsa *)v->lsa;
+  
+  for (i = 0; i < ntohs (rl->links); i++)
+    {
+      switch (rl->link[i].type)
+	{
+	case LSA_LINK_TYPE_VIRTUALLINK:
+	  if (IS_DEBUG_OSPF_EVENT)
+	    zlog_info ("found back link through VL");
+	case LSA_LINK_TYPE_TRANSIT:
+	case LSA_LINK_TYPE_POINTOPOINT:
+	  vl_data->peer_addr = rl->link[i].link_data;
+	  if (IS_DEBUG_OSPF_EVENT)
+	    zlog_info ("%s peer address is %s\n",
+		       vl_data->vl_oi->ifp->name, inet_ntoa(vl_data->peer_addr));
+	  return;
+	}
+    }
+}
+
+
+void
+ospf_vl_up_check (struct ospf_area * area, struct in_addr rid,
+                  struct vertex *v)
+{
+  listnode node;
+  struct ospf_vl_data *vl_data;
+  struct ospf_interface *oi;
+
+  if (IS_DEBUG_OSPF_EVENT)
+    {
+      zlog_info ("ospf_vl_up_check(): Start");
+      zlog_info ("ospf_vl_up_check(): Router ID is %s", inet_ntoa (rid));
+      zlog_info ("ospf_vl_up_check(): Area is %s", inet_ntoa (area->area_id));
+    }
+
+  for (node = listhead (ospf_top->vlinks); node; nextnode (node))
+    {
+      if ((vl_data = getdata (node)) == NULL)
+        continue;
+  
+      if (IS_DEBUG_OSPF_EVENT)
+	{
+	  zlog_info ("ospf_vl_up_check(): considering VL, name: %s", 
+		     vl_data->vl_oi->ifp->name);
+	  zlog_info ("ospf_vl_up_check(): VL area: %s, peer ID: %s", 
+		     inet_ntoa (vl_data->vl_area_id),
+		     inet_ntoa (vl_data->vl_peer));
+	}
+
+      if (IPV4_ADDR_SAME (&vl_data->vl_peer, &rid) &&
+          IPV4_ADDR_SAME (&vl_data->vl_area_id, &area->area_id))
+        {
+          oi = vl_data->vl_oi;
+          SET_FLAG (vl_data->flags, OSPF_VL_FLAG_APPROVED);
+
+	  if (IS_DEBUG_OSPF_EVENT)
+	    zlog_info ("ospf_vl_up_check(): this VL matched");
+
+          if (oi->state == ISM_Down)
+            {
+	      if (IS_DEBUG_OSPF_EVENT)
+		zlog_info ("ospf_vl_up_check(): VL is down, waking it up");
+              SET_FLAG (oi->ifp->flags, IFF_UP);
+              OSPF_ISM_EVENT_SCHEDULE (oi, ISM_InterfaceUp);
+            }
+
+          ospf_vl_set_params (vl_data, v);
+        }
+    }
+}
+
+void
+ospf_vl_unapprove ()
+{
+  listnode node;
+  struct ospf_vl_data *vl_data;
+
+  for (node = listhead (ospf_top->vlinks); node; nextnode (node))
+    if ((vl_data = getdata (node)) != NULL)
+      UNSET_FLAG (vl_data->flags, OSPF_VL_FLAG_APPROVED);
+}
+
+void
+ospf_vl_shut_unapproved ()
+{
+  listnode node;
+  struct ospf_vl_data *vl_data;
+
+  for (node = listhead (ospf_top->vlinks); node; nextnode (node))
+    if ((vl_data = getdata (node)) != NULL)
+      if (!CHECK_FLAG (vl_data->flags, OSPF_VL_FLAG_APPROVED))
+        ospf_vl_shutdown (vl_data);
+}
+
+int
+ospf_full_virtual_nbrs (struct ospf_area *area)
+{
+  if (IS_DEBUG_OSPF_EVENT)
+    {
+      zlog_info ("counting fully adjacent virtual neighbors in area %s",
+		 inet_ntoa (area->area_id));
+      zlog_info ("there are %d of them", area->full_vls);
+    }
+
+  return area->full_vls;
+}
+
+int
+ospf_vls_in_area (struct ospf_area *area)
+{
+  listnode node;
+  struct ospf_vl_data *vl_data;
+  int c = 0;
+
+  for (node = listhead (ospf_top->vlinks); node; nextnode (node))
+    if ((vl_data = getdata (node)) != NULL)
+      if (IPV4_ADDR_SAME (&vl_data->vl_area_id, &area->area_id))
+        c++;
+
+  return c;
+}
+
+
+struct crypt_key *
+ospf_crypt_key_new ()
+{
+  struct crypt_key *ck;
+
+  ck = XMALLOC (MTYPE_OSPF_CRYPT_KEY, sizeof (struct crypt_key));
+  memset (ck, 0, sizeof (struct crypt_key));
+
+  return ck;
+}
+
+void
+ospf_crypt_key_add (list crypt, struct crypt_key *ck)
+{
+  listnode_add (crypt, ck);
+}
+
+struct crypt_key *
+ospf_crypt_key_lookup (list auth_crypt, u_char key_id)
+{
+  listnode node;
+  struct crypt_key *ck;
+
+  for (node = listhead (auth_crypt); node; nextnode (node))
+    {
+      ck = getdata (node);
+      if (ck->key_id == key_id)
+        return ck;
+    }
+
+  return NULL;
+}
+
+int
+ospf_crypt_key_delete (list auth_crypt, u_char key_id)
+{
+  listnode node;
+  struct crypt_key *ck;
+
+  for (node = listhead (auth_crypt); node; nextnode (node))
+    {
+      ck = getdata (node);
+      if (ck->key_id == key_id)
+        {
+          listnode_delete (auth_crypt, ck);
+          return 1;
+        }
+    }
+
+  return 0;
+}
+
+void
+ospf_if_init ()
+{
+  /* Initialize Zebra interface data structure. */
+  if_init ();
+  if_add_hook (IF_NEW_HOOK, ospf_if_new_hook);
+  if_add_hook (IF_DELETE_HOOK, ospf_if_delete_hook);
+}