diff --git a/ospfd/ospf_ism.c b/ospfd/ospf_ism.c
new file mode 100644
index 0000000..b47487f
--- /dev/null
+++ b/ospfd/ospf_ism.c
@@ -0,0 +1,658 @@
+/*
+ * OSPF version 2  Interface State Machine
+ *   From RFC2328 [OSPF Version 2] 
+ * 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 "log.h"
+
+#include "ospfd/ospfd.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_network.h"
+#include "ospfd/ospf_dump.h"
+#include "ospfd/ospf_packet.h"
+#include "ospfd/ospf_flood.h"
+#include "ospfd/ospf_abr.h"
+
+/* elect DR and BDR. Refer to RFC2319 section 9.4 */
+struct ospf_neighbor *
+ospf_dr_election_sub (list routers)
+{
+  listnode node;
+  struct ospf_neighbor *nbr, *max = NULL;
+
+  /* Choose highest router priority.
+     In case of tie, choose highest Router ID. */
+  for (node = listhead (routers); node; nextnode (node))
+    {
+      nbr = getdata (node);
+
+      if (max == NULL)
+	max = nbr;
+      else
+	{
+	  if (max->priority < nbr->priority)
+	    max = nbr;
+	  else if (max->priority == nbr->priority)
+	    if (IPV4_ADDR_CMP (&max->router_id, &nbr->router_id) < 0)
+	      max = nbr;
+	}
+    }
+
+  return max;
+}
+
+struct ospf_neighbor *
+ospf_elect_dr (struct ospf_interface *oi, list el_list)
+{
+  list dr_list;
+  listnode node;
+  struct ospf_neighbor *nbr, *dr = NULL, *bdr = NULL;
+
+  dr_list = list_new ();
+
+  /* Add neighbors to the list. */
+  for (node = listhead (el_list); node; nextnode (node))
+    {
+      nbr = getdata (node);
+
+      /* neighbor declared to be DR. */
+      if (NBR_IS_DR (nbr))
+	listnode_add (dr_list, nbr);
+
+      /* Preserve neighbor BDR. */
+      if (IPV4_ADDR_SAME (&BDR (oi), &nbr->address.u.prefix4))
+	bdr = nbr;
+    }
+
+  /* Elect Designated Router. */
+  if (listcount (dr_list) > 0)
+    dr = ospf_dr_election_sub (dr_list);
+  else
+    dr = bdr;
+
+  /* Set DR to interface. */
+  if (dr)
+    {
+      DR (oi) = dr->address.u.prefix4;
+      dr->d_router = dr->address.u.prefix4;
+    }
+  else
+      DR (oi).s_addr = 0;
+
+  list_delete (dr_list);
+
+  return dr;
+}
+
+struct ospf_neighbor *
+ospf_elect_bdr (struct ospf_interface *oi, list el_list)
+{
+  list bdr_list, no_dr_list;
+  listnode node;
+  struct ospf_neighbor *nbr, *bdr = NULL;
+
+  bdr_list = list_new ();
+  no_dr_list = list_new ();
+
+  /* Add neighbors to the list. */
+  for (node = listhead (el_list); node; nextnode (node))
+    {
+      nbr = getdata (node);
+
+      /* neighbor declared to be DR. */
+      if (NBR_IS_DR (nbr))
+	continue;
+
+      /* neighbor declared to be BDR. */
+      if (NBR_IS_BDR (nbr))
+	listnode_add (bdr_list, nbr);
+
+      listnode_add (no_dr_list, nbr);
+    }
+
+  /* Elect Backup Designated Router. */
+  if (listcount (bdr_list) > 0)
+    bdr = ospf_dr_election_sub (bdr_list);
+  else
+    bdr = ospf_dr_election_sub (no_dr_list);
+
+  /* Set BDR to interface. */
+  if (bdr)
+    {
+      BDR (oi) = bdr->address.u.prefix4;
+      bdr->bd_router = bdr->address.u.prefix4;
+    }
+  else
+    BDR (oi).s_addr = 0;
+
+  list_delete (bdr_list);
+  list_delete (no_dr_list);
+
+  return bdr;
+}
+
+int
+ospf_ism_state (struct ospf_interface *oi)
+{
+  if (IPV4_ADDR_SAME (&DR (oi), &oi->address->u.prefix4))
+    return ISM_DR;
+  else if (IPV4_ADDR_SAME (&BDR (oi), &oi->address->u.prefix4))
+    return ISM_Backup;
+  else
+    return ISM_DROther;
+}
+
+void
+ospf_dr_eligible_routers (struct route_table *nbrs, list el_list)
+{
+  struct route_node *rn;
+  struct ospf_neighbor *nbr;
+
+  for (rn = route_top (nbrs); rn; rn = route_next (rn))
+    if ((nbr = rn->info) != NULL)
+      /* Ignore 0.0.0.0 node*/
+      if (nbr->router_id.s_addr != 0)
+	/* Is neighbor eligible? */
+	if (nbr->priority != 0)
+	  /* Is neighbor upper 2-Way? */
+	  if (nbr->state >= NSM_TwoWay)
+	    listnode_add (el_list, nbr);
+}
+
+/* Generate AdjOK? NSM event. */
+void
+ospf_dr_change (struct route_table *nbrs)
+{
+  struct route_node *rn;
+  struct ospf_neighbor *nbr;
+
+  for (rn = route_top (nbrs); rn; rn = route_next (rn))
+    if ((nbr = rn->info) != NULL)
+      /* Ignore 0.0.0.0 node*/
+      if (nbr->router_id.s_addr != 0)
+	/* Is neighbor upper 2-Way? */
+	if (nbr->state >= NSM_TwoWay)
+	  /* Ignore myself. */
+	  if (!IPV4_ADDR_SAME (&nbr->router_id, &ospf_top->router_id))
+	    OSPF_NSM_EVENT_SCHEDULE (nbr, NSM_AdjOK);
+}
+
+int
+ospf_dr_election (struct ospf_interface *oi)
+{
+  struct in_addr old_dr, old_bdr;
+  int old_state, new_state;
+  list el_list;
+  struct ospf_neighbor *dr, *bdr;
+
+  /* backup current values. */
+  old_dr = DR (oi);
+  old_bdr = BDR (oi);
+  old_state = oi->state;
+
+  el_list = list_new ();
+
+  /* List eligible routers. */
+  ospf_dr_eligible_routers (oi->nbrs, el_list);
+
+  /* First election of DR and BDR. */
+  bdr = ospf_elect_bdr (oi, el_list);
+  dr = ospf_elect_dr (oi, el_list);
+
+  new_state = ospf_ism_state (oi);
+
+  zlog_info ("DR-Election[1st]: Backup %s", inet_ntoa (BDR (oi)));
+  zlog_info ("DR-Election[1st]: DR     %s", inet_ntoa (DR (oi)));
+
+  if (new_state != old_state &&
+      !(new_state == ISM_DROther && old_state < ISM_DROther))
+    {
+      ospf_elect_bdr (oi, el_list);
+      ospf_elect_dr (oi, el_list); 
+
+      new_state = ospf_ism_state (oi);
+
+      zlog_info ("DR-Election[2nd]: Backup %s", inet_ntoa (BDR (oi)));
+      zlog_info ("DR-Election[2nd]: DR     %s", inet_ntoa (DR (oi)));
+    }
+
+  list_delete (el_list);
+
+  /* if DR or BDR changes, cause AdjOK? neighbor event. */
+  if (!IPV4_ADDR_SAME (&old_dr, &DR (oi)) ||
+      !IPV4_ADDR_SAME (&old_bdr, &BDR (oi)))
+    ospf_dr_change (oi->nbrs);
+
+  if (oi->type == OSPF_IFTYPE_BROADCAST || oi->type == OSPF_IFTYPE_POINTOPOINT)
+    {
+      /* Multicast group change. */
+      if ((old_state != ISM_DR && old_state != ISM_Backup) &&
+	  (new_state == ISM_DR || new_state == ISM_Backup))
+	ospf_if_add_alldrouters (ospf_top, oi->address, oi->ifp->ifindex);
+      else if ((old_state == ISM_DR || old_state == ISM_Backup) &&
+	       (new_state != ISM_DR && new_state != ISM_Backup))
+	ospf_if_drop_alldrouters (ospf_top, oi->address, oi->ifp->ifindex);
+    }
+
+  return new_state;
+}
+
+
+int
+ospf_hello_timer (struct thread *thread)
+{
+  struct ospf_interface *oi;
+
+  oi = THREAD_ARG (thread);
+  oi->t_hello = NULL;
+
+  if (IS_DEBUG_OSPF (ism, ISM_TIMERS))
+    zlog (NULL, LOG_DEBUG, "ISM[%s]: Timer (Hello timer expire)",
+	  IF_NAME (oi));
+
+  /* Sending hello packet. */
+  ospf_hello_send (oi);
+
+  /* Hello timer set. */
+  OSPF_ISM_TIMER_ON (oi->t_hello, ospf_hello_timer,
+		     OSPF_IF_PARAM (oi, v_hello));
+
+  return 0;
+}
+
+int
+ospf_wait_timer (struct thread *thread)
+{
+  struct ospf_interface *oi;
+
+  oi = THREAD_ARG (thread);
+  oi->t_wait = NULL;
+
+  if (IS_DEBUG_OSPF (ism, ISM_TIMERS))
+    zlog (NULL, LOG_DEBUG, "ISM[%s]: Timer (Wait timer expire)",
+	  IF_NAME (oi));
+
+  OSPF_ISM_EVENT_SCHEDULE (oi, ISM_WaitTimer);
+
+  return 0;
+}
+
+/* Hook function called after ospf ISM event is occured. And vty's
+   network command invoke this function after making interface
+   structure. */
+void
+ism_timer_set (struct ospf_interface *oi)
+{
+  switch (oi->state)
+    {
+    case ISM_Down:
+      /* First entry point of ospf interface state machine. In this state
+	 interface parameters must be set to initial values, and timers are
+	 reset also. */
+      OSPF_ISM_TIMER_OFF (oi->t_hello);
+      OSPF_ISM_TIMER_OFF (oi->t_wait);
+      OSPF_ISM_TIMER_OFF (oi->t_ls_ack);
+      break;
+    case ISM_Loopback:
+      /* In this state, the interface may be looped back and will be
+	 unavailable for regular data traffic. */
+      OSPF_ISM_TIMER_OFF (oi->t_hello);
+      OSPF_ISM_TIMER_OFF (oi->t_wait);
+      OSPF_ISM_TIMER_OFF (oi->t_ls_ack);
+      break;
+    case ISM_Waiting:
+      /* The router is trying to determine the identity of DRouter and
+	 BDRouter. The router begin to receive and send Hello Packets. */
+      /* send first hello immediately */
+      OSPF_ISM_TIMER_ON (oi->t_hello, ospf_hello_timer, 1);
+      OSPF_ISM_TIMER_ON (oi->t_wait, ospf_wait_timer,
+			 OSPF_IF_PARAM (oi, v_wait));
+      OSPF_ISM_TIMER_OFF (oi->t_ls_ack);
+      break;
+    case ISM_PointToPoint:
+      /* The interface connects to a physical Point-to-point network or
+	 virtual link. The router attempts to form an adjacency with
+	 neighboring router. Hello packets are also sent. */
+      /* send first hello immediately */
+      OSPF_ISM_TIMER_ON (oi->t_hello, ospf_hello_timer, 1);
+      
+      OSPF_ISM_TIMER_OFF (oi->t_wait);
+      OSPF_ISM_TIMER_ON (oi->t_ls_ack, ospf_ls_ack_timer, oi->v_ls_ack);
+      break;
+    case ISM_DROther:
+      /* The network type of the interface is broadcast or NBMA network,
+	 and the router itself is neither Designated Router nor
+	 Backup Designated Router. */
+      OSPF_ISM_TIMER_ON (oi->t_hello, ospf_hello_timer,
+			 OSPF_IF_PARAM (oi, v_hello));
+      OSPF_ISM_TIMER_OFF (oi->t_wait);
+      OSPF_ISM_TIMER_ON (oi->t_ls_ack, ospf_ls_ack_timer, oi->v_ls_ack);
+      break;
+    case ISM_Backup:
+      /* The network type of the interface is broadcast os NBMA network,
+	 and the router is Backup Designated Router. */
+      OSPF_ISM_TIMER_ON (oi->t_hello, ospf_hello_timer,
+			 OSPF_IF_PARAM (oi, v_hello));
+      OSPF_ISM_TIMER_OFF (oi->t_wait);
+      OSPF_ISM_TIMER_ON (oi->t_ls_ack, ospf_ls_ack_timer, oi->v_ls_ack);
+      break;
+    case ISM_DR:
+      /* The network type of the interface is broadcast or NBMA network,
+	 and the router is Designated Router. */
+      OSPF_ISM_TIMER_ON (oi->t_hello, ospf_hello_timer,
+			 OSPF_IF_PARAM (oi, v_hello));
+      OSPF_ISM_TIMER_OFF (oi->t_wait);
+      OSPF_ISM_TIMER_ON (oi->t_ls_ack, ospf_ls_ack_timer, oi->v_ls_ack);
+      break;
+    }
+}
+
+int
+ism_stop (struct ospf_interface *oi)
+{
+  return 0;
+}
+
+int
+ism_interface_up (struct ospf_interface *oi)
+{
+  int next_state = 0;
+
+  /* if network type is point-to-point, Point-to-MultiPoint or virtual link,
+     the state transitions to Point-to-Point. */
+  if (oi->type == OSPF_IFTYPE_POINTOPOINT ||
+      oi->type == OSPF_IFTYPE_POINTOMULTIPOINT ||
+      oi->type == OSPF_IFTYPE_VIRTUALLINK)
+    next_state = ISM_PointToPoint;
+  /* Else if the router is not eligible to DR, the state transitions to
+     DROther. */
+  else if (PRIORITY (oi) == 0) /* router is eligible? */
+    next_state = ISM_DROther;
+  else
+    /* Otherwise, the state transitions to Waiting. */
+    next_state = ISM_Waiting;
+
+  if (oi->type == OSPF_IFTYPE_NBMA)
+    ospf_nbr_nbma_if_update (oi);
+
+  /*  ospf_ism_event (t); */
+  return next_state;
+}
+
+int
+ism_loop_ind (struct ospf_interface *oi)
+{
+  int ret = 0;
+
+  /* call ism_interface_down. */
+  /* ret = ism_interface_down (oi); */
+
+  return ret;
+}
+
+/* Interface down event handler. */
+int
+ism_interface_down (struct ospf_interface *oi)
+{
+  ospf_if_cleanup (oi);
+  return 0;
+}
+
+
+int
+ism_backup_seen (struct ospf_interface *oi)
+{
+  return ospf_dr_election (oi);
+}
+
+int
+ism_wait_timer (struct ospf_interface *oi)
+{
+  return ospf_dr_election (oi);
+}
+
+int
+ism_neighbor_change (struct ospf_interface *oi)
+{
+  return ospf_dr_election (oi);
+}
+
+int
+ism_ignore (struct ospf_interface *oi)
+{
+  if (IS_DEBUG_OSPF (ism, ISM_EVENTS))
+    zlog (NULL, LOG_INFO, "ISM[%s]: ism_ignore called", IF_NAME (oi));
+
+  return 0;
+}
+
+/* Interface State Machine */
+struct {
+  int (*func) ();
+  int next_state;
+} ISM [OSPF_ISM_STATE_MAX][OSPF_ISM_EVENT_MAX] =
+{
+  {
+    /* DependUpon: dummy state. */
+    { ism_ignore,          ISM_DependUpon },    /* NoEvent        */
+    { ism_ignore,          ISM_DependUpon },    /* InterfaceUp    */
+    { ism_ignore,          ISM_DependUpon },    /* WaitTimer      */
+    { ism_ignore,          ISM_DependUpon },    /* BackupSeen     */
+    { ism_ignore,          ISM_DependUpon },    /* NeighborChange */
+    { ism_ignore,          ISM_DependUpon },    /* LoopInd        */
+    { ism_ignore,          ISM_DependUpon },    /* UnloopInd      */
+    { ism_ignore,          ISM_DependUpon },    /* InterfaceDown  */
+  },
+  {
+    /* Down:*/
+    { ism_ignore,          ISM_DependUpon },    /* NoEvent        */
+    { ism_interface_up,    ISM_DependUpon },    /* InterfaceUp    */
+    { ism_ignore,          ISM_Down },          /* WaitTimer      */
+    { ism_ignore,          ISM_Down },          /* BackupSeen     */
+    { ism_ignore,          ISM_Down },          /* NeighborChange */
+    { ism_loop_ind,        ISM_Loopback },      /* LoopInd        */
+    { ism_ignore,          ISM_Down },          /* UnloopInd      */
+    { ism_interface_down,  ISM_Down },          /* InterfaceDown  */
+  },
+  {
+    /* Loopback: */
+    { ism_ignore,          ISM_DependUpon },    /* NoEvent        */
+    { ism_ignore,          ISM_Loopback },      /* InterfaceUp    */
+    { ism_ignore,          ISM_Loopback },      /* WaitTimer      */
+    { ism_ignore,          ISM_Loopback },      /* BackupSeen     */
+    { ism_ignore,          ISM_Loopback },      /* NeighborChange */
+    { ism_ignore,          ISM_Loopback },      /* LoopInd        */
+    { ism_ignore,          ISM_Down },          /* UnloopInd      */
+    { ism_interface_down,  ISM_Down },          /* InterfaceDown  */
+  },
+  {
+    /* Waiting: */
+    { ism_ignore,          ISM_DependUpon },    /* NoEvent        */
+    { ism_ignore,          ISM_Waiting },       /* InterfaceUp    */
+    { ism_wait_timer,	   ISM_DependUpon },    /* WaitTimer      */
+    { ism_backup_seen,     ISM_DependUpon },    /* BackupSeen     */
+    { ism_ignore,          ISM_Waiting },       /* NeighborChange */
+    { ism_loop_ind,	   ISM_Loopback },      /* LoopInd        */
+    { ism_ignore,          ISM_Waiting },       /* UnloopInd      */
+    { ism_interface_down,  ISM_Down },          /* InterfaceDown  */
+  },
+  {
+    /* Point-to-Point: */
+    { ism_ignore,          ISM_DependUpon },    /* NoEvent        */
+    { ism_ignore,          ISM_PointToPoint },  /* InterfaceUp    */
+    { ism_ignore,          ISM_PointToPoint },  /* WaitTimer      */
+    { ism_ignore,          ISM_PointToPoint },  /* BackupSeen     */
+    { ism_ignore,          ISM_PointToPoint },  /* NeighborChange */
+    { ism_loop_ind,	   ISM_Loopback },      /* LoopInd        */
+    { ism_ignore,          ISM_PointToPoint },  /* UnloopInd      */
+    { ism_interface_down,  ISM_Down },          /* InterfaceDown  */
+  },
+  {
+    /* DROther: */
+    { ism_ignore,          ISM_DependUpon },    /* NoEvent        */
+    { ism_ignore,          ISM_DROther },       /* InterfaceUp    */
+    { ism_ignore,          ISM_DROther },       /* WaitTimer      */
+    { ism_ignore,          ISM_DROther },       /* BackupSeen     */
+    { ism_neighbor_change, ISM_DependUpon },    /* NeighborChange */
+    { ism_loop_ind,        ISM_Loopback },      /* LoopInd        */
+    { ism_ignore,          ISM_DROther },       /* UnloopInd      */
+    { ism_interface_down,  ISM_Down },          /* InterfaceDown  */
+  },
+  {
+    /* Backup: */
+    { ism_ignore,          ISM_DependUpon },    /* NoEvent        */
+    { ism_ignore,          ISM_Backup },        /* InterfaceUp    */
+    { ism_ignore,          ISM_Backup },        /* WaitTimer      */
+    { ism_ignore,          ISM_Backup },        /* BackupSeen     */
+    { ism_neighbor_change, ISM_DependUpon },    /* NeighborChange */
+    { ism_loop_ind,        ISM_Loopback },      /* LoopInd        */
+    { ism_ignore,          ISM_Backup },        /* UnloopInd      */
+    { ism_interface_down,  ISM_Down },          /* InterfaceDown  */
+  },
+  {
+    /* DR: */
+    { ism_ignore,          ISM_DependUpon },    /* NoEvent        */
+    { ism_ignore,          ISM_DR },            /* InterfaceUp    */
+    { ism_ignore,          ISM_DR },            /* WaitTimer      */
+    { ism_ignore,          ISM_DR },            /* BackupSeen     */
+    { ism_neighbor_change, ISM_DependUpon },    /* NeighborChange */
+    { ism_loop_ind,        ISM_Loopback },      /* LoopInd        */
+    { ism_ignore,          ISM_DR },            /* UnloopInd      */
+    { ism_interface_down,  ISM_Down },          /* InterfaceDown  */
+  },
+};  
+
+static char *ospf_ism_event_str[] =
+{
+  "NoEvent",
+  "InterfaceUp",
+  "WaitTimer",
+  "BackupSeen",
+  "NeighborChange",
+  "LoopInd",
+  "UnLoopInd",
+  "InterfaceDown",
+};
+
+void
+ism_change_state (struct ospf_interface *oi, int state)
+{
+  int old_state;
+  struct ospf_lsa *lsa;
+
+  /* Logging change of state. */
+  if (IS_DEBUG_OSPF (ism, ISM_STATUS))
+    zlog (NULL, LOG_INFO, "ISM[%s]: State change %s -> %s", IF_NAME (oi),
+	  LOOKUP (ospf_ism_state_msg, oi->state),
+	  LOOKUP (ospf_ism_state_msg, state));
+
+  old_state = oi->state;
+  oi->state = state;
+  oi->state_change++;
+
+  if (old_state == ISM_Down || state == ISM_Down)
+    ospf_check_abr_status();
+
+  /* Originate router-LSA. */
+  if (oi->area)
+    {
+      if (state == ISM_Down)
+	{
+	  if (oi->area->act_ints > 0)
+	    oi->area->act_ints--;
+	}
+      else if (old_state == ISM_Down)
+	oi->area->act_ints++;
+
+      /* schedule router-LSA originate. */
+      ospf_router_lsa_timer_add (oi->area);
+    }
+
+  /* Originate network-LSA. */
+  if (old_state != ISM_DR && state == ISM_DR)
+    ospf_network_lsa_timer_add (oi);
+  else if (old_state == ISM_DR && state != ISM_DR)
+    {
+      /* Free self originated network LSA. */
+      lsa = oi->network_lsa_self;
+      if (lsa)
+	{
+	  ospf_lsa_flush_area (lsa, oi->area);
+	  OSPF_TIMER_OFF (oi->t_network_lsa_self);
+	}
+
+      ospf_lsa_unlock (oi->network_lsa_self);
+      oi->network_lsa_self = NULL;
+    }
+
+#ifdef HAVE_OPAQUE_LSA
+  ospf_opaque_ism_change (oi, old_state);
+#endif /* HAVE_OPAQUE_LSA */
+
+  /* Check area border status.  */
+  ospf_check_abr_status ();
+}
+
+/* Execute ISM event process. */
+int
+ospf_ism_event (struct thread *thread)
+{
+  int event;
+  int next_state;
+  struct ospf_interface *oi;
+
+  oi = THREAD_ARG (thread);
+  event = THREAD_VAL (thread);
+
+  /* Call function. */
+  next_state = (*(ISM [oi->state][event].func))(oi);
+
+  if (! next_state)
+    next_state = ISM [oi->state][event].next_state;
+
+  if (IS_DEBUG_OSPF (ism, ISM_EVENTS))
+    zlog (NULL, LOG_INFO, "ISM[%s]: %s (%s)", IF_NAME (oi),
+	  LOOKUP (ospf_ism_state_msg, oi->state),
+	  ospf_ism_event_str[event]);
+
+  /* If state is changed. */
+  if (next_state != oi->state)
+    ism_change_state (oi, next_state);
+
+  /* Make sure timer is set. */
+  ism_timer_set (oi);
+
+  return 0;
+}
+
diff --git a/ospfd/ospf_neighbor.c b/ospfd/ospf_neighbor.c
new file mode 100644
index 0000000..a302aa9
--- /dev/null
+++ b/ospfd/ospf_neighbor.c
@@ -0,0 +1,329 @@
+/*
+ * OSPF Neighbor 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 "linklist.h"
+#include "prefix.h"
+#include "memory.h"
+#include "command.h"
+#include "thread.h"
+#include "stream.h"
+#include "table.h"
+#include "log.h"
+
+#include "ospfd/ospfd.h"
+#include "ospfd/ospf_interface.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_network.h"
+#include "ospfd/ospf_flood.h"
+#include "ospfd/ospf_dump.h"
+
+struct ospf_neighbor *
+ospf_nbr_new (struct ospf_interface *oi)
+{
+  struct ospf_neighbor *nbr;
+
+  /* Allcate new neighbor. */
+  nbr = XMALLOC (MTYPE_OSPF_NEIGHBOR, sizeof (struct ospf_neighbor));
+  memset (nbr, 0, sizeof (struct ospf_neighbor));
+
+  /* Relate neighbor to the interface. */
+  nbr->oi = oi;
+
+  /* Set default values. */
+  nbr->state = NSM_Down;
+
+  /* Set inheritance values. */
+  nbr->v_inactivity = OSPF_IF_PARAM (oi, v_wait);
+  nbr->v_db_desc = OSPF_IF_PARAM (oi, retransmit_interval);
+  nbr->v_ls_req = OSPF_IF_PARAM (oi, retransmit_interval);
+  nbr->v_ls_upd = OSPF_IF_PARAM (oi, retransmit_interval);
+  nbr->priority = -1;
+
+  /* DD flags. */
+  nbr->dd_flags = OSPF_DD_FLAG_MS|OSPF_DD_FLAG_M|OSPF_DD_FLAG_I;
+
+  /* Last received and sent DD. */
+  nbr->last_send = NULL;
+
+  nbr->nbr_nbma = NULL;
+
+  ospf_lsdb_init (&nbr->db_sum);
+  ospf_lsdb_init (&nbr->ls_rxmt);
+  ospf_lsdb_init (&nbr->ls_req);
+
+  nbr->crypt_seqnum = 0;
+
+  return nbr;
+}
+
+void
+ospf_nbr_free (struct ospf_neighbor *nbr)
+{
+  /* Free DB summary list. */
+  if (ospf_db_summary_count (nbr))
+    ospf_db_summary_clear (nbr);
+    /* ospf_db_summary_delete_all (nbr); */
+
+  /* Free ls request list. */
+  if (ospf_ls_request_count (nbr))
+    ospf_ls_request_delete_all (nbr);
+
+  /* Free retransmit list. */
+  if (ospf_ls_retransmit_count (nbr))
+    ospf_ls_retransmit_clear (nbr);
+
+  /* Cleanup LSDBs. */
+  ospf_lsdb_cleanup (&nbr->db_sum);
+  ospf_lsdb_cleanup (&nbr->ls_req);
+  ospf_lsdb_cleanup (&nbr->ls_rxmt);
+  
+  /* Clear last send packet. */
+  if (nbr->last_send)
+    ospf_packet_free (nbr->last_send);
+
+  if (nbr->nbr_nbma)
+    {
+      nbr->nbr_nbma->nbr = NULL;
+      nbr->nbr_nbma = NULL;
+    }
+
+  /* Cancel all timers. */
+  OSPF_NSM_TIMER_OFF (nbr->t_inactivity);
+  OSPF_NSM_TIMER_OFF (nbr->t_db_desc);
+  OSPF_NSM_TIMER_OFF (nbr->t_ls_req);
+  OSPF_NSM_TIMER_OFF (nbr->t_ls_upd);
+
+  /* Cancel all events. *//* Thread lookup cost would be negligible. */
+  thread_cancel_event (master, nbr);
+
+  XFREE (MTYPE_OSPF_NEIGHBOR, nbr);
+}
+
+/* Delete specified OSPF neighbor from interface. */
+void
+ospf_nbr_delete (struct ospf_neighbor *nbr)
+{
+  struct ospf_interface *oi;
+  struct route_node *rn;
+  struct prefix p;
+
+  oi = nbr->oi;
+
+  /* Unlink ospf neighbor from the interface. */
+  p.family = AF_INET;
+  p.prefixlen = IPV4_MAX_BITLEN;
+  p.u.prefix4 = nbr->src;
+
+  rn = route_node_lookup (oi->nbrs, &p);
+  if (rn)
+    {
+      if (rn->info)
+	{
+	  rn->info = NULL;
+	  route_unlock_node (rn);
+	}
+      else
+	zlog_info ("Can't find neighbor %s in the interface %s",
+		   inet_ntoa (nbr->src), IF_NAME (oi));
+
+      route_unlock_node (rn);
+    }
+
+  /* Free ospf_neighbor structure. */
+  ospf_nbr_free (nbr);
+}
+
+/* Check myself is in the neighbor list. */
+int
+ospf_nbr_bidirectional (struct in_addr *router_id,
+			struct in_addr *neighbors, int size)
+{
+  int i;
+  int max;
+
+  max = size / sizeof (struct in_addr);
+
+  for (i = 0; i < max; i ++)
+    if (IPV4_ADDR_SAME (router_id, &neighbors[i]))
+      return 1;
+
+  return 0;
+}
+
+/* Add self to nbr list. */
+void
+ospf_nbr_add_self (struct ospf_interface *oi)
+{
+  struct ospf_neighbor *nbr;
+  struct prefix p;
+  struct route_node *rn;
+
+  p.family = AF_INET;
+  p.prefixlen = 32;
+  p.u.prefix4 = oi->address->u.prefix4;
+
+  rn = route_node_get (oi->nbrs, &p);
+  if (rn->info)
+    {
+      /* There is already pseudo neighbor. */
+      nbr = rn->info;
+      route_unlock_node (rn);
+    }
+  else
+    rn->info = oi->nbr_self;
+}
+
+/* Get neighbor count by status.
+   Specify status = 0, get all neighbor other than myself. */
+int
+ospf_nbr_count (struct route_table *nbrs, int state)
+{
+  struct route_node *rn;
+  struct ospf_neighbor *nbr;
+  int count = 0;
+
+  /* Sanity check. */
+  if (nbrs == NULL)
+    return 0;
+
+  for (rn = route_top (nbrs); rn; rn = route_next (rn))
+    if ((nbr = rn->info) != NULL)
+      /* Ignore myself. */
+      if (!IPV4_ADDR_SAME (&nbr->router_id, &ospf_top->router_id))
+	if (state == 0 || nbr->state == state)
+	  count++;
+
+  return count;
+}
+
+#ifdef HAVE_OPAQUE_LSA
+int
+ospf_opaque_capable_nbr_count (struct route_table *nbrs, int state)
+{
+  struct route_node *rn;
+  struct ospf_neighbor *nbr;
+  int count = 0;
+
+  /* Sanity check. */
+  if (nbrs == NULL)
+    return 0;
+
+  for (rn = route_top (nbrs); rn; rn = route_next (rn))
+    if ((nbr = rn->info) != NULL)
+      /* Ignore myself. */
+      if (!IPV4_ADDR_SAME (&nbr->router_id, &ospf_top->router_id))
+	if ((state == 0 || nbr->state == state)
+	&&  CHECK_FLAG (nbr->options, OSPF_OPTION_O))
+	  count++;
+
+  return count;
+}
+#endif /* HAVE_OPAQUE_LSA */
+
+struct ospf_neighbor *
+ospf_nbr_lookup_by_addr (struct route_table *nbrs,
+			 struct in_addr *addr)
+{
+  struct prefix p;
+  struct route_node *rn;
+  struct ospf_neighbor *nbr;
+
+  p.family = AF_INET;
+  p.prefixlen = IPV4_MAX_BITLEN;
+  p.u.prefix4 = *addr;
+
+  rn = route_node_lookup (nbrs, &p);
+  if (! rn)
+    return NULL;
+
+  if (rn->info == NULL)
+    {
+      route_unlock_node (rn);
+      return NULL;
+    }
+
+  nbr = (struct ospf_neighbor *) rn->info;
+  route_unlock_node (rn);
+
+  return nbr;
+}
+
+struct ospf_neighbor *
+ospf_nbr_lookup_by_routerid (struct route_table *nbrs,
+			     struct in_addr *id)
+{
+  struct route_node *rn;
+  struct ospf_neighbor *nbr;
+
+  for (rn = route_top (nbrs); rn; rn = route_next (rn))
+    if ((nbr = rn->info) != NULL)
+      if (IPV4_ADDR_SAME (&nbr->router_id, id))
+	{
+	  route_unlock_node(rn);
+	  return nbr;
+	}
+
+  return NULL;
+}
+
+void
+ospf_renegotiate_optional_capabilities (struct ospf *top)
+{
+  listnode node;
+  struct ospf_interface *oi;
+  struct route_table *nbrs;
+  struct route_node *rn;
+  struct ospf_neighbor *nbr;
+
+  /* At first, flush self-originated LSAs from routing domain. */
+  ospf_flush_self_originated_lsas_now (top);
+
+  /* Revert all neighbor status to ExStart. */
+  for (node = listhead (top->oiflist); node; nextnode (node))
+    {
+      if ((oi = getdata (node)) == NULL || (nbrs = oi->nbrs) == NULL)
+        continue;
+
+      for (rn = route_top (nbrs); rn; rn = route_next (rn))
+        {
+          if ((nbr = rn->info) == NULL || nbr == oi->nbr_self)
+            continue;
+
+          if (nbr->state < NSM_ExStart)
+            continue;
+
+          if (IS_DEBUG_OSPF_EVENT)
+            zlog_info ("Renegotiate optional capabilities with neighbor(%s)", inet_ntoa (nbr->router_id));
+
+          OSPF_NSM_EVENT_SCHEDULE (nbr, NSM_SeqNumberMismatch);
+        }
+    }
+
+  return;
+}
diff --git a/ospfd/ospf_nsm.c b/ospfd/ospf_nsm.c
new file mode 100644
index 0000000..cfb18a9
--- /dev/null
+++ b/ospfd/ospf_nsm.c
@@ -0,0 +1,879 @@
+/*
+ * OSPF version 2  Neighbor State Machine
+ * From RFC2328 [OSPF Version 2]
+ * 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 "memory.h"
+#include "hash.h"
+#include "linklist.h"
+#include "prefix.h"
+#include "if.h"
+#include "table.h"
+#include "stream.h"
+#include "table.h"
+#include "log.h"
+
+#include "ospfd/ospfd.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_network.h"
+#include "ospfd/ospf_packet.h"
+#include "ospfd/ospf_dump.h"
+#include "ospfd/ospf_flood.h"
+#include "ospfd/ospf_abr.h"
+
+void nsm_reset_nbr (struct ospf_neighbor *);
+
+
+/* OSPF NSM Timer functions. */
+int
+ospf_inactivity_timer (struct thread *thread)
+{
+  struct ospf_neighbor *nbr;
+
+  nbr = THREAD_ARG (thread);
+  nbr->t_inactivity = NULL;
+
+  if (IS_DEBUG_OSPF (nsm, NSM_TIMERS))
+    zlog (NULL, LOG_DEBUG, "NSM[%s:%s]: Timer (Inactivity timer expire)",
+	  IF_NAME (nbr->oi), inet_ntoa (nbr->router_id));
+
+  OSPF_NSM_EVENT_SCHEDULE (nbr, NSM_InactivityTimer);
+
+  return 0;
+}
+
+int
+ospf_db_desc_timer (struct thread *thread)
+{
+  struct ospf_interface *oi;
+  struct ospf_neighbor *nbr;
+
+  nbr = THREAD_ARG (thread);
+  nbr->t_db_desc = NULL;
+
+  oi = nbr->oi;
+
+  if (IS_DEBUG_OSPF (nsm, NSM_TIMERS))
+    zlog (NULL, LOG_INFO, "NSM[%s:%s]: Timer (DD Retransmit timer expire)",
+	  IF_NAME (nbr->oi), inet_ntoa (nbr->src));
+
+  /* resent last send DD packet. */
+  assert (nbr->last_send);
+  ospf_db_desc_resend (nbr);
+
+  /* DD Retransmit timer set. */
+  OSPF_NSM_TIMER_ON (nbr->t_db_desc, ospf_db_desc_timer, nbr->v_db_desc);
+
+  return 0;
+}
+
+/* Hook function called after ospf NSM event is occured. */
+
+void
+nsm_timer_set (struct ospf_neighbor *nbr)
+{
+  switch (nbr->state)
+    {
+    case NSM_Down:
+      OSPF_NSM_TIMER_OFF (nbr->t_db_desc);
+      OSPF_NSM_TIMER_OFF (nbr->t_ls_upd);
+      break;
+    case NSM_Attempt:
+      OSPF_NSM_TIMER_OFF (nbr->t_db_desc);
+      OSPF_NSM_TIMER_OFF (nbr->t_ls_upd);
+      break;
+    case NSM_Init:
+      OSPF_NSM_TIMER_OFF (nbr->t_db_desc);
+      OSPF_NSM_TIMER_OFF (nbr->t_ls_upd);
+      break;
+    case NSM_TwoWay:
+      OSPF_NSM_TIMER_OFF (nbr->t_db_desc);
+      OSPF_NSM_TIMER_OFF (nbr->t_ls_upd);
+      break;
+    case NSM_ExStart:
+      OSPF_NSM_TIMER_ON (nbr->t_db_desc, ospf_db_desc_timer, nbr->v_db_desc);
+      OSPF_NSM_TIMER_OFF (nbr->t_ls_upd);
+      break;
+    case NSM_Exchange:
+      OSPF_NSM_TIMER_ON (nbr->t_ls_upd, ospf_ls_upd_timer, nbr->v_ls_upd);
+      if (!IS_SET_DD_MS (nbr->dd_flags))      
+	OSPF_NSM_TIMER_OFF (nbr->t_db_desc);
+      break;
+    case NSM_Loading:
+      OSPF_NSM_TIMER_OFF (nbr->t_db_desc);
+      break;
+    case NSM_Full:
+      OSPF_NSM_TIMER_OFF (nbr->t_db_desc);
+      break;
+    default:
+      OSPF_NSM_TIMER_OFF (nbr->t_db_desc);
+      break;
+    }
+}
+
+
+/* OSPF NSM functions. */
+int
+nsm_ignore (struct ospf_neighbor *nbr)
+{
+  if (IS_DEBUG_OSPF (nsm, NSM_EVENTS))
+    zlog (NULL, LOG_INFO, "NSM[%s:%s]: nsm_ignore called",
+	  IF_NAME (nbr->oi), inet_ntoa (nbr->router_id));
+
+  return 0;
+}
+
+int
+nsm_hello_received (struct ospf_neighbor *nbr)
+{
+  /* Start or Restart Inactivity Timer. */
+  OSPF_NSM_TIMER_OFF (nbr->t_inactivity);
+  
+  OSPF_NSM_TIMER_ON (nbr->t_inactivity, ospf_inactivity_timer,
+		     nbr->v_inactivity);
+
+  if (nbr->oi->type == OSPF_IFTYPE_NBMA && nbr->nbr_nbma)
+    OSPF_POLL_TIMER_OFF (nbr->nbr_nbma->t_poll);
+
+  return 0;
+}
+
+int
+nsm_start (struct ospf_neighbor *nbr)
+{
+
+  nsm_reset_nbr (nbr);
+
+  if (nbr->nbr_nbma)
+      OSPF_POLL_TIMER_OFF (nbr->nbr_nbma->t_poll);
+
+  OSPF_NSM_TIMER_OFF (nbr->t_inactivity);
+  
+  OSPF_NSM_TIMER_ON (nbr->t_inactivity, ospf_inactivity_timer,
+                     nbr->v_inactivity);
+
+  return 0;
+}
+
+int
+nsm_twoway_received (struct ospf_neighbor *nbr)
+{
+  struct ospf_interface *oi;
+  int next_state = NSM_TwoWay;
+
+  oi = nbr->oi;
+
+  /* These netowork types must be adjacency. */
+  if (oi->type == OSPF_IFTYPE_POINTOPOINT ||
+      oi->type == OSPF_IFTYPE_POINTOMULTIPOINT ||
+      oi->type == OSPF_IFTYPE_VIRTUALLINK)
+    next_state = NSM_ExStart;
+
+  /* Router itself is the DRouter or the BDRouter. */
+  if (IPV4_ADDR_SAME (&oi->address->u.prefix4, &DR (oi)) ||
+      IPV4_ADDR_SAME (&oi->address->u.prefix4, &BDR (oi)))
+    next_state = NSM_ExStart;
+
+  /* Neighboring Router is the DRouter or the BDRouter. */
+  if (IPV4_ADDR_SAME (&nbr->address.u.prefix4, &nbr->d_router) ||
+      IPV4_ADDR_SAME (&nbr->address.u.prefix4, &nbr->bd_router))
+    next_state = NSM_ExStart;
+
+  return next_state;
+}
+
+int
+ospf_db_summary_count (struct ospf_neighbor *nbr)
+{
+  return ospf_lsdb_count_all (&nbr->db_sum);
+}
+
+int
+ospf_db_summary_isempty (struct ospf_neighbor *nbr)
+{
+  return ospf_lsdb_isempty (&nbr->db_sum);
+}
+
+int
+ospf_db_summary_add (struct ospf_lsa *lsa, void *v, int i)
+{
+  struct ospf_neighbor *nbr = (struct ospf_neighbor *) v;
+
+  if (lsa == NULL)
+    return 0;
+
+#ifdef HAVE_NSSA
+  /* Stay away from any Local Translated Type-7 LSAs */
+  if (CHECK_FLAG (lsa->flags, OSPF_LSA_LOCAL_XLT))
+    return 0;
+#endif /* HAVE_NSSA */
+
+  if (IS_LSA_MAXAGE (lsa))
+    ospf_ls_retransmit_add (nbr, lsa);                      
+  else 
+    ospf_lsdb_add (&nbr->db_sum, lsa);
+
+  return 0;
+}
+
+void
+ospf_db_summary_clear (struct ospf_neighbor *nbr)
+{
+  struct ospf_lsdb *lsdb;
+  int i;
+
+  lsdb = &nbr->db_sum;
+  for (i = OSPF_MIN_LSA; i < OSPF_MAX_LSA; i++)
+    {
+      struct route_table *table = lsdb->type[i].db;
+      struct route_node *rn;
+
+      for (rn = route_top (table); rn; rn = route_next (rn))
+	if (rn->info)
+	  ospf_lsdb_delete (&nbr->db_sum, rn->info);
+    }
+}
+
+
+
+#ifdef HAVE_OPAQUE_LSA
+/* The area link state database consists of the router-LSAs,
+   network-LSAs, summary-LSAs, and type-9/10 opaque-LSAs contained
+			     ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   in the area structure, along with the AS-external and type-11
+						     ^^^^^^^^^^^
+   opaque LSAs contained in the global structure.
+   ^^^^^^
+   AS-external and type-11 opaque LSAs are omitted from a virtual
+	       ^^^^^^^^^^^^^^^^^^
+   neighbor's Database summary list. AS-external and type-11 opaque
+						 ^^^^^^^^^^^^^^^^^^
+   LSAs are omitted from the Database summary list if the area has
+   been configured as a stub. */
+#else /* HAVE_OPAQUE_LSA */
+/* The area link state database consists of the router-LSAs,
+   network-LSAs and summary-LSAs contained in the area structure,
+   along with the AS-external- LSAs contained in the global structure.
+   AS- external-LSAs are omitted from a virtual neighbor's Database
+   summary list.  AS-external-LSAs are omitted from the Database
+   summary list if the area has been configured as a stub. */
+#endif /* HAVE_OPAQUE_LSA */
+int
+nsm_negotiation_done (struct ospf_neighbor *nbr)
+{
+  struct ospf_area *area;
+
+  area = nbr->oi->area;
+
+  foreach_lsa (ROUTER_LSDB (area), nbr, 0, ospf_db_summary_add);
+  foreach_lsa (NETWORK_LSDB (area), nbr, 0, ospf_db_summary_add);
+  foreach_lsa (SUMMARY_LSDB (area), nbr, 0, ospf_db_summary_add);
+  foreach_lsa (ASBR_SUMMARY_LSDB (area), nbr, 0, ospf_db_summary_add);
+  
+#ifdef HAVE_OPAQUE_LSA
+  /* Process only if the neighbor is opaque capable. */
+  if (CHECK_FLAG (nbr->options, OSPF_OPTION_O))
+    {
+      foreach_lsa (OPAQUE_LINK_LSDB (area), nbr, 0, ospf_db_summary_add);
+      foreach_lsa (OPAQUE_AREA_LSDB (area), nbr, 0, ospf_db_summary_add);
+    }
+#endif /* HAVE_OPAQUE_LSA */
+
+  if (nbr->oi->type != OSPF_IFTYPE_VIRTUALLINK &&
+      area->external_routing == OSPF_AREA_DEFAULT)
+    foreach_lsa (EXTERNAL_LSDB (ospf_top), nbr, 0, ospf_db_summary_add);
+
+#ifdef HAVE_OPAQUE_LSA
+  if (CHECK_FLAG (nbr->options, OSPF_OPTION_O) &&
+      (nbr->oi->type != OSPF_IFTYPE_VIRTUALLINK &&
+       area->external_routing == OSPF_AREA_DEFAULT))
+    foreach_lsa (OPAQUE_AS_LSDB (ospf_top),
+		 nbr, 0, ospf_db_summary_add);
+#endif /* HAVE_OPAQUE_LSA */
+
+  /* OSPF_NSM_TIMER_OFF (nbr->t_db_desc); */
+
+  return 0;
+}
+
+int
+nsm_exchange_done (struct ospf_neighbor *nbr)
+{
+  struct ospf_interface *oi;
+
+  oi = nbr->oi;
+
+  if (ospf_ls_request_isempty (nbr))
+    return NSM_Full;
+
+  /* Cancel dd retransmit timer. */
+  /* OSPF_NSM_TIMER_OFF (nbr->t_db_desc); */
+
+  /* Send Link State Request. */
+  ospf_ls_req_send (nbr);
+
+  return NSM_Loading;
+}
+
+int
+nsm_bad_ls_req (struct ospf_neighbor *nbr)
+{
+  /* Clear neighbor. */
+  nsm_reset_nbr (nbr);
+
+  return 0;
+}
+
+int
+nsm_adj_ok (struct ospf_neighbor *nbr)
+{
+  struct ospf_interface *oi;
+  int next_state;
+  int flag = 0;
+
+  oi = nbr->oi;
+  next_state = nbr->state;
+
+  /* These netowork types must be adjacency. */
+  if (oi->type == OSPF_IFTYPE_POINTOPOINT ||
+      oi->type == OSPF_IFTYPE_POINTOMULTIPOINT ||
+      oi->type == OSPF_IFTYPE_VIRTUALLINK)
+    flag = 1;
+
+  /* Router itself is the DRouter or the BDRouter. */
+  if (IPV4_ADDR_SAME (&oi->address->u.prefix4, &DR (oi)) ||
+      IPV4_ADDR_SAME (&oi->address->u.prefix4, &BDR (oi)))
+    flag = 1;
+
+  if (IPV4_ADDR_SAME (&nbr->address.u.prefix4, &DR (oi)) ||
+      IPV4_ADDR_SAME (&nbr->address.u.prefix4, &BDR (oi)))
+    flag = 1;
+
+  if (nbr->state == NSM_TwoWay && flag == 1)
+    next_state = NSM_ExStart;
+  else if (nbr->state >= NSM_ExStart && flag == 0)
+    next_state = NSM_TwoWay;
+
+  return next_state;
+}
+
+int
+nsm_seq_number_mismatch (struct ospf_neighbor *nbr)
+{
+  /* Clear neighbor. */
+  nsm_reset_nbr (nbr);
+
+  return 0;
+}
+
+int
+nsm_oneway_received (struct ospf_neighbor *nbr)
+{
+  /* Clear neighbor. */
+  nsm_reset_nbr (nbr);
+
+  return 0;
+}
+
+void
+nsm_reset_nbr (struct ospf_neighbor *nbr)
+{
+  /* Clear Database Summary list. */
+  if (!ospf_db_summary_isempty (nbr))
+    ospf_db_summary_clear (nbr);
+
+  /* Clear Link State Request list. */
+  if (!ospf_ls_request_isempty (nbr))
+    ospf_ls_request_delete_all (nbr);
+
+  /* Clear Link State Retransmission list. */
+  if (!ospf_ls_retransmit_isempty (nbr))
+    ospf_ls_retransmit_clear (nbr);
+
+  /* Cancel thread. */
+  OSPF_NSM_TIMER_OFF (nbr->t_db_desc);
+  OSPF_NSM_TIMER_OFF (nbr->t_ls_req);
+  OSPF_NSM_TIMER_OFF (nbr->t_ls_upd);
+  OSPF_NSM_TIMER_OFF (nbr->t_hello_reply);
+
+#ifdef HAVE_OPAQUE_LSA
+  if (CHECK_FLAG (nbr->options, OSPF_OPTION_O))
+    UNSET_FLAG (nbr->options, OSPF_OPTION_O);
+#endif /* HAVE_OPAQUE_LSA */
+}
+
+int
+nsm_kill_nbr (struct ospf_neighbor *nbr)
+{
+  /* call it here because we cannot call it from ospf_nsm_event */
+  nsm_change_state (nbr, NSM_Down);
+  
+  /* Reset neighbor. */
+  nsm_reset_nbr (nbr);
+
+  if (nbr->oi->type == OSPF_IFTYPE_NBMA && nbr->nbr_nbma != NULL)
+    {
+      struct ospf_nbr_nbma *nbr_nbma = nbr->nbr_nbma;
+
+      nbr_nbma->nbr = NULL;
+      nbr_nbma->state_change = nbr->state_change;
+
+      nbr->nbr_nbma = NULL;
+
+      OSPF_POLL_TIMER_ON (nbr_nbma->t_poll, ospf_poll_timer,
+			  nbr_nbma->v_poll);
+
+      if (IS_DEBUG_OSPF (nsm, NSM_EVENTS))
+	zlog_info ("NSM[%s:%s]: Down (PollIntervalTimer scheduled)",
+		   IF_NAME (nbr->oi), inet_ntoa (nbr->address.u.prefix4));  
+    }
+
+  /* Delete neighbor from interface. */
+  ospf_nbr_delete (nbr);
+
+  return 0;
+}
+
+int
+nsm_inactivity_timer (struct ospf_neighbor *nbr)
+{
+  /* Kill neighbor. */
+  nsm_kill_nbr (nbr);
+
+  return 0;
+}
+
+int
+nsm_ll_down (struct ospf_neighbor *nbr)
+{
+  /* Reset neighbor. */
+  /*nsm_reset_nbr (nbr);*/
+  
+  /* Kill neighbor. */
+  nsm_kill_nbr (nbr);
+
+  return 0;
+}
+
+/* Neighbor State Machine */
+struct {
+  int (*func) ();
+  int next_state;
+} NSM [OSPF_NSM_STATE_MAX][OSPF_NSM_EVENT_MAX] =
+{
+  {
+    /* DependUpon: dummy state. */
+    { nsm_ignore,              NSM_DependUpon }, /* NoEvent           */
+    { nsm_ignore,              NSM_DependUpon }, /* HelloReceived     */
+    { nsm_ignore,              NSM_DependUpon }, /* Start             */
+    { nsm_ignore,              NSM_DependUpon }, /* 2-WayReceived     */
+    { nsm_ignore,              NSM_DependUpon }, /* NegotiationDone   */
+    { nsm_ignore,              NSM_DependUpon }, /* ExchangeDone      */
+    { nsm_ignore,              NSM_DependUpon }, /* BadLSReq          */
+    { nsm_ignore,              NSM_DependUpon }, /* LoadingDone       */
+    { nsm_ignore,              NSM_DependUpon }, /* AdjOK?            */
+    { nsm_ignore,              NSM_DependUpon }, /* SeqNumberMismatch */
+    { nsm_ignore,              NSM_DependUpon }, /* 1-WayReceived     */
+    { nsm_ignore,              NSM_DependUpon }, /* KillNbr           */
+    { nsm_ignore,              NSM_DependUpon }, /* InactivityTimer   */
+    { nsm_ignore,              NSM_DependUpon }, /* LLDown            */
+  },
+  {
+    /* Down: */
+    { nsm_ignore,              NSM_DependUpon }, /* NoEvent           */
+    { nsm_hello_received,      NSM_Init       }, /* HelloReceived     */
+    { nsm_start,               NSM_Attempt    }, /* Start             */
+    { nsm_ignore,              NSM_Down       }, /* 2-WayReceived     */
+    { nsm_ignore,              NSM_Down       }, /* NegotiationDone   */
+    { nsm_ignore,              NSM_Down       }, /* ExchangeDone      */
+    { nsm_ignore,              NSM_Down       }, /* BadLSReq          */
+    { nsm_ignore,              NSM_Down       }, /* LoadingDone       */
+    { nsm_ignore,              NSM_Down       }, /* AdjOK?            */
+    { nsm_ignore,              NSM_Down       }, /* SeqNumberMismatch */
+    { nsm_ignore,              NSM_Down       }, /* 1-WayReceived     */
+    { nsm_kill_nbr,            NSM_Down       }, /* KillNbr           */
+    { nsm_inactivity_timer,    NSM_Down       }, /* InactivityTimer   */
+    { nsm_ll_down,             NSM_Down       }, /* LLDown            */
+  },
+  {
+    /* Attempt: */
+    { nsm_ignore,              NSM_DependUpon }, /* NoEvent           */
+    { nsm_hello_received,      NSM_Init       }, /* HelloReceived     */
+    { nsm_ignore,              NSM_Attempt    }, /* Start             */
+    { nsm_ignore,              NSM_Attempt    }, /* 2-WayReceived     */
+    { nsm_ignore,              NSM_Attempt    }, /* NegotiationDone   */
+    { nsm_ignore,              NSM_Attempt    }, /* ExchangeDone      */
+    { nsm_ignore,              NSM_Attempt    }, /* BadLSReq          */
+    { nsm_ignore,              NSM_Attempt    }, /* LoadingDone       */
+    { nsm_ignore,              NSM_Attempt    }, /* AdjOK?            */
+    { nsm_ignore,              NSM_Attempt    }, /* SeqNumberMismatch */
+    { nsm_ignore,              NSM_Attempt    }, /* 1-WayReceived     */
+    { nsm_kill_nbr,            NSM_Down       }, /* KillNbr           */
+    { nsm_inactivity_timer,    NSM_Down       }, /* InactivityTimer   */
+    { nsm_ll_down,             NSM_Down       }, /* LLDown            */
+  },
+  {
+    /* Init: */
+    { nsm_ignore,              NSM_DependUpon }, /* NoEvent           */
+    { nsm_hello_received,      NSM_Init       }, /* HelloReceived     */
+    { nsm_ignore,              NSM_Init       }, /* Start             */
+    { nsm_twoway_received,     NSM_DependUpon }, /* 2-WayReceived     */
+    { nsm_ignore,              NSM_Init       }, /* NegotiationDone   */
+    { nsm_ignore,              NSM_Init       }, /* ExchangeDone      */
+    { nsm_ignore,              NSM_Init       }, /* BadLSReq          */
+    { nsm_ignore,              NSM_Init       }, /* LoadingDone       */
+    { nsm_ignore,              NSM_Init       }, /* AdjOK?            */
+    { nsm_ignore,              NSM_Init       }, /* SeqNumberMismatch */
+    { nsm_ignore,              NSM_Init       }, /* 1-WayReceived     */
+    { nsm_kill_nbr,            NSM_Down       }, /* KillNbr           */
+    { nsm_inactivity_timer,    NSM_Down       }, /* InactivityTimer   */
+    { nsm_ll_down,             NSM_Down       }, /* LLDown            */
+  },
+  {
+    /* 2-Way: */
+    { nsm_ignore,              NSM_DependUpon }, /* NoEvent           */
+    { nsm_hello_received,      NSM_TwoWay     }, /* HelloReceived     */
+    { nsm_ignore,              NSM_TwoWay     }, /* Start             */
+    { nsm_ignore,              NSM_TwoWay     }, /* 2-WayReceived     */
+    { nsm_ignore,              NSM_TwoWay     }, /* NegotiationDone   */
+    { nsm_ignore,              NSM_TwoWay     }, /* ExchangeDone      */
+    { nsm_ignore,              NSM_TwoWay     }, /* BadLSReq          */
+    { nsm_ignore,              NSM_TwoWay     }, /* LoadingDone       */
+    { nsm_adj_ok,              NSM_DependUpon }, /* AdjOK?            */
+    { nsm_ignore,              NSM_TwoWay     }, /* SeqNumberMismatch */
+    { nsm_oneway_received,     NSM_Init       }, /* 1-WayReceived     */
+    { nsm_kill_nbr,            NSM_Down       }, /* KillNbr           */
+    { nsm_inactivity_timer,    NSM_Down       }, /* InactivityTimer   */
+    { nsm_ll_down,             NSM_Down       }, /* LLDown            */
+  },
+  {
+    /* ExStart: */
+    { nsm_ignore,              NSM_DependUpon }, /* NoEvent           */
+    { nsm_hello_received,      NSM_ExStart    }, /* HelloReceived     */
+    { nsm_ignore,              NSM_ExStart    }, /* Start             */
+    { nsm_ignore,              NSM_ExStart    }, /* 2-WayReceived     */
+    { nsm_negotiation_done,    NSM_Exchange   }, /* NegotiationDone   */
+    { nsm_ignore,              NSM_ExStart    }, /* ExchangeDone      */
+    { nsm_ignore,              NSM_ExStart    }, /* BadLSReq          */
+    { nsm_ignore,              NSM_ExStart    }, /* LoadingDone       */
+    { nsm_adj_ok,              NSM_DependUpon }, /* AdjOK?            */
+    { nsm_ignore,              NSM_ExStart    }, /* SeqNumberMismatch */
+    { nsm_oneway_received,     NSM_Init       }, /* 1-WayReceived     */
+    { nsm_kill_nbr,            NSM_Down       }, /* KillNbr           */
+    { nsm_inactivity_timer,    NSM_Down       }, /* InactivityTimer   */
+    { nsm_ll_down,             NSM_Down       }, /* LLDown            */
+  },
+  {
+    /* Exchange: */
+    { nsm_ignore,              NSM_DependUpon }, /* NoEvent           */
+    { nsm_hello_received,      NSM_Exchange   }, /* HelloReceived     */
+    { nsm_ignore,              NSM_Exchange   }, /* Start             */
+    { nsm_ignore,              NSM_Exchange   }, /* 2-WayReceived     */
+    { nsm_ignore,              NSM_Exchange   }, /* NegotiationDone   */
+    { nsm_exchange_done,       NSM_DependUpon }, /* ExchangeDone      */
+    { nsm_bad_ls_req,          NSM_ExStart    }, /* BadLSReq          */
+    { nsm_ignore,              NSM_Exchange   }, /* LoadingDone       */
+    { nsm_adj_ok,              NSM_DependUpon }, /* AdjOK?            */
+    { nsm_seq_number_mismatch, NSM_ExStart    }, /* SeqNumberMismatch */
+    { nsm_oneway_received,     NSM_Init       }, /* 1-WayReceived     */
+    { nsm_kill_nbr,            NSM_Down       }, /* KillNbr           */
+    { nsm_inactivity_timer,    NSM_Down       }, /* InactivityTimer   */
+    { nsm_ll_down,             NSM_Down       }, /* LLDown            */
+  },
+  {
+    /* Loading: */
+    { nsm_ignore,              NSM_DependUpon }, /* NoEvent           */
+    { nsm_hello_received,      NSM_Loading    }, /* HelloReceived     */
+    { nsm_ignore,              NSM_Loading    }, /* Start             */
+    { nsm_ignore,              NSM_Loading    }, /* 2-WayReceived     */
+    { nsm_ignore,              NSM_Loading    }, /* NegotiationDone   */
+    { nsm_ignore,              NSM_Loading    }, /* ExchangeDone      */
+    { nsm_bad_ls_req,          NSM_ExStart    }, /* BadLSReq          */
+    { nsm_ignore,              NSM_Full       }, /* LoadingDone       */
+    { nsm_adj_ok,              NSM_DependUpon }, /* AdjOK?            */
+    { nsm_seq_number_mismatch, NSM_ExStart    }, /* SeqNumberMismatch */
+    { nsm_oneway_received,     NSM_Init       }, /* 1-WayReceived     */
+    { nsm_kill_nbr,            NSM_Down       }, /* KillNbr           */
+    { nsm_inactivity_timer,    NSM_Down       }, /* InactivityTimer   */
+    { nsm_ll_down,             NSM_Down       }, /* LLDown            */
+  },
+  { /* Full: */
+    { nsm_ignore,              NSM_DependUpon }, /* NoEvent           */
+    { nsm_hello_received,      NSM_Full       }, /* HelloReceived     */
+    { nsm_ignore,              NSM_Full       }, /* Start             */
+    { nsm_ignore,              NSM_Full       }, /* 2-WayReceived     */
+    { nsm_ignore,              NSM_Full       }, /* NegotiationDone   */
+    { nsm_ignore,              NSM_Full       }, /* ExchangeDone      */
+    { nsm_bad_ls_req,          NSM_ExStart    }, /* BadLSReq          */
+    { nsm_ignore,              NSM_Full       }, /* LoadingDone       */
+    { nsm_adj_ok,              NSM_DependUpon }, /* AdjOK?            */
+    { nsm_seq_number_mismatch, NSM_ExStart    }, /* SeqNumberMismatch */
+    { nsm_oneway_received,     NSM_Init       }, /* 1-WayReceived     */
+    { nsm_kill_nbr,            NSM_Down       }, /* KillNbr           */
+    { nsm_inactivity_timer,    NSM_Down       }, /* InactivityTimer   */
+    { nsm_ll_down,             NSM_Down       }, /* LLDown            */
+  },
+};
+
+static char *ospf_nsm_event_str[] =
+{
+  "NoEvent",
+  "HelloReceived",
+  "Start",
+  "2-WayReceived",
+  "NegotiationDone",
+  "ExchangeDone",
+  "BadLSReq",
+  "LoadingDone",
+  "AdjOK?",
+  "SeqNumberMismatch",
+  "1-WayReceived",
+  "KillNbr",
+  "InactivityTimer",
+  "LLDown",
+};
+
+void
+nsm_change_state (struct ospf_neighbor *nbr, int state)
+{
+  struct ospf_interface *oi;
+  struct ospf_area *vl_area = NULL;
+  u_char old_state;
+  int x;
+  int force = 1;
+  
+  /* Logging change of status. */
+  if (IS_DEBUG_OSPF (nsm, NSM_STATUS))
+    zlog_info ("NSM[%s:%s]: State change %s -> %s",
+	       IF_NAME (nbr->oi), inet_ntoa (nbr->router_id),
+	       LOOKUP (ospf_nsm_state_msg, nbr->state),
+	       LOOKUP (ospf_nsm_state_msg, state));
+
+  /* Preserve old status. */
+  old_state = nbr->state;
+
+  /* Change to new status. */
+  nbr->state = state;
+
+  /* Statistics. */
+  nbr->state_change++;
+
+  oi = nbr->oi;
+
+  if (oi->type == OSPF_IFTYPE_VIRTUALLINK)
+    vl_area = ospf_area_lookup_by_area_id (oi->vl_data->vl_area_id);
+  
+  /* One of the neighboring routers changes to/from the FULL state. */
+  if ((old_state != NSM_Full && state == NSM_Full) ||
+      (old_state == NSM_Full && state != NSM_Full))
+    { 
+      if (state == NSM_Full)
+	{
+	  oi->full_nbrs++;
+	  oi->area->full_nbrs++;
+
+          ospf_check_abr_status ();
+
+	  if (oi->type == OSPF_IFTYPE_VIRTUALLINK && vl_area)
+            if (++vl_area->full_vls == 1)
+	      ospf_schedule_abr_task ();
+
+	  /* kevinm: refresh any redistributions */
+	  for (x = ZEBRA_ROUTE_SYSTEM; x < ZEBRA_ROUTE_MAX; x++) {
+	    if (x == ZEBRA_ROUTE_OSPF || x == ZEBRA_ROUTE_OSPF6)
+	      continue;
+	    ospf_external_lsa_refresh_type(x, force);
+	  }
+
+	}
+      else
+	{
+	  oi->full_nbrs--;
+	  oi->area->full_nbrs--;
+
+          ospf_check_abr_status ();
+
+	  if (oi->type == OSPF_IFTYPE_VIRTUALLINK && vl_area)
+	    if (vl_area->full_vls > 0)
+	      if (--vl_area->full_vls == 0)
+		ospf_schedule_abr_task ();
+ 
+          /* clear neighbor retransmit list */
+          if (!ospf_ls_retransmit_isempty (nbr))
+            ospf_ls_retransmit_clear (nbr);
+	}
+
+      zlog_info ("nsm_change_state(): "
+		 "scheduling new router-LSA origination");
+
+      ospf_router_lsa_timer_add (oi->area);
+
+      if (oi->type == OSPF_IFTYPE_VIRTUALLINK)
+	{
+	  struct ospf_area *vl_area =
+	    ospf_area_lookup_by_area_id (oi->vl_data->vl_area_id);
+	  
+	  if (vl_area)
+	    ospf_router_lsa_timer_add (vl_area);
+	}
+
+      /* Originate network-LSA. */
+      if (oi->state == ISM_DR)
+	{
+	  if (oi->network_lsa_self && oi->full_nbrs == 0)
+	    {
+	      ospf_lsa_flush_area (oi->network_lsa_self, oi->area);
+	      ospf_lsa_unlock (oi->network_lsa_self);
+	      oi->network_lsa_self = NULL;
+	      OSPF_TIMER_OFF (oi->t_network_lsa_self);
+	    }
+	  else
+	    ospf_network_lsa_timer_add (oi);
+	}
+    }
+
+#ifdef HAVE_OPAQUE_LSA
+  ospf_opaque_nsm_change (nbr, old_state);
+#endif /* HAVE_OPAQUE_LSA */
+
+  /* Start DD exchange protocol */
+  if (state == NSM_ExStart)
+    {
+      if (nbr->dd_seqnum == 0)
+	nbr->dd_seqnum = time (NULL);
+      else
+	nbr->dd_seqnum++;
+
+      nbr->dd_flags = OSPF_DD_FLAG_I|OSPF_DD_FLAG_M|OSPF_DD_FLAG_MS;
+      ospf_db_desc_send (nbr);
+    }
+
+  /* clear cryptographic sequence number */
+  if (state == NSM_Down)
+    nbr->crypt_seqnum = 0;
+  
+  /* Generete NeighborChange ISM event. */
+#ifdef BUGGY_ISM_TRANSITION
+  if ((old_state < NSM_TwoWay && state >= NSM_TwoWay) ||
+      (old_state >= NSM_TwoWay && state < NSM_TwoWay))
+    OSPF_ISM_EVENT_EXECUTE (oi, ISM_NeighborChange);
+#else /* BUGGY_ISM_TRANSITION */
+  switch (oi->state) {
+  case ISM_DROther:
+  case ISM_Backup:
+  case ISM_DR:
+    if ((old_state < NSM_TwoWay && state >= NSM_TwoWay) ||
+        (old_state >= NSM_TwoWay && state < NSM_TwoWay))
+      OSPF_ISM_EVENT_EXECUTE (oi, ISM_NeighborChange);
+    break;
+  default:
+    /* ISM_PointToPoint -> ISM_Down, ISM_Loopback -> ISM_Down, etc. */
+    break;
+  }
+#endif /* BUGGY_ISM_TRANSITION */
+
+  /* Performance hack. Send hello immideately when some neighbor enter
+     Init state.  This whay we decrease neighbor discovery time. Gleb.*/
+  if (state == NSM_Init)
+    {
+      OSPF_ISM_TIMER_OFF (oi->t_hello);
+      OSPF_ISM_TIMER_ON (oi->t_hello, ospf_hello_timer, 1);
+    }
+
+  /* Preserve old status? */
+}
+
+/* Execute NSM event process. */
+int
+ospf_nsm_event (struct thread *thread)
+{
+  int event;
+  int next_state;
+  struct ospf_neighbor *nbr;
+  struct in_addr router_id;
+  int old_state;
+  struct ospf_interface *oi;
+
+  nbr = THREAD_ARG (thread);
+  event = THREAD_VAL (thread);
+  router_id = nbr->router_id;
+
+  old_state = nbr->state;
+  oi = nbr->oi ;
+  
+  /* Call function. */
+  next_state = (*(NSM [nbr->state][event].func))(nbr);
+
+  /* When event is NSM_KillNbr or InactivityTimer, the neighbor is
+     deleted. */
+  if (event == NSM_KillNbr || event == NSM_InactivityTimer)
+    {
+      if (IS_DEBUG_OSPF (nsm, NSM_EVENTS))
+	zlog_info ("NSM[%s:%s]: neighbor deleted",
+		   IF_NAME (oi), inet_ntoa (router_id));
+
+      /* Timers are canceled in ospf_nbr_free, moreover we cannot call
+         nsm_timer_set here because nbr is freed already!!!*/
+      /*nsm_timer_set (nbr);*/
+
+      return 0;
+    }
+
+  if (! next_state)
+    next_state = NSM [nbr->state][event].next_state;
+
+  if (IS_DEBUG_OSPF (nsm, NSM_EVENTS))
+    zlog_info ("NSM[%s:%s]: %s (%s)", IF_NAME (oi),
+	       inet_ntoa (nbr->router_id),
+	       LOOKUP (ospf_nsm_state_msg, nbr->state),
+	       ospf_nsm_event_str [event]);
+  
+  /* If state is changed. */
+  if (next_state != nbr->state)
+    nsm_change_state (nbr, next_state);
+
+  /* Make sure timer is set. */
+  nsm_timer_set (nbr);
+
+  return 0;
+}
+
+/* Check loading state. */
+void
+ospf_check_nbr_loading (struct ospf_neighbor *nbr)
+{
+  if (nbr->state == NSM_Loading)
+    {
+      if (ospf_ls_request_isempty (nbr))
+	OSPF_NSM_EVENT_SCHEDULE (nbr, NSM_LoadingDone);
+      else if (nbr->ls_req_last == NULL)
+	ospf_ls_req_event (nbr);
+    }
+}