/*
 * Interface function.
 * Copyright (C) 1997, 1999 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 "if.h"
#include "vty.h"
#include "sockunion.h"
#include "prefix.h"
#include "command.h"
#include "memory.h"
#include "ioctl.h"
#include "connected.h"
#include "log.h"
#include "zclient.h"

#include "zebra/interface.h"
#include "zebra/rtadv.h"
#include "zebra/rib.h"
#include "zebra/zserv.h"
#include "zebra/redistribute.h"
#include "zebra/debug.h"
#include "zebra/irdp.h"


/* Called when new interface is added. */
static int
if_zebra_new_hook (struct interface *ifp)
{
  struct zebra_if *zebra_if;

  zebra_if = XMALLOC (MTYPE_TMP, sizeof (struct zebra_if));
  memset (zebra_if, 0, sizeof (struct zebra_if));

  zebra_if->multicast = IF_ZEBRA_MULTICAST_UNSPEC;
  zebra_if->shutdown = IF_ZEBRA_SHUTDOWN_UNSPEC;

#ifdef RTADV
  {
    /* Set default router advertise values. */
    struct rtadvconf *rtadv;

    rtadv = &zebra_if->rtadv;

    rtadv->AdvSendAdvertisements = 0;
    rtadv->MaxRtrAdvInterval = RTADV_MAX_RTR_ADV_INTERVAL;
    rtadv->MinRtrAdvInterval = RTADV_MIN_RTR_ADV_INTERVAL;
    rtadv->AdvIntervalTimer = 0;
    rtadv->AdvManagedFlag = 0;
    rtadv->AdvOtherConfigFlag = 0;
    rtadv->AdvHomeAgentFlag = 0;
    rtadv->AdvLinkMTU = 0;
    rtadv->AdvReachableTime = 0;
    rtadv->AdvRetransTimer = 0;
    rtadv->AdvCurHopLimit = 0;
    rtadv->AdvDefaultLifetime = RTADV_ADV_DEFAULT_LIFETIME;
    rtadv->HomeAgentPreference = 0;
    rtadv->HomeAgentLifetime = RTADV_ADV_DEFAULT_LIFETIME;
    rtadv->AdvIntervalOption = 0;

    rtadv->AdvPrefixList = list_new ();
  }    
#endif /* RTADV */

  /* Initialize installed address chains tree. */
  zebra_if->ipv4_subnets = route_table_init ();

  ifp->info = zebra_if;
  return 0;
}

/* Called when interface is deleted. */
static int
if_zebra_delete_hook (struct interface *ifp)
{
  struct zebra_if *zebra_if;
  
  if (ifp->info)
    {
      zebra_if = ifp->info;

      /* Free installed address chains tree. */
      if (zebra_if->ipv4_subnets)
	route_table_finish (zebra_if->ipv4_subnets);

      XFREE (MTYPE_TMP, zebra_if);
    }

  return 0;
}

/* Tie an interface address to its derived subnet list of addresses. */
int
if_subnet_add (struct interface *ifp, struct connected *ifc)
{
  struct route_node *rn;
  struct zebra_if *zebra_if;
  struct prefix cp;
  struct list *addr_list;

  assert (ifp && ifp->info && ifc);
  zebra_if = ifp->info;

  /* Get address derived subnet node and associated address list, while marking
     address secondary attribute appropriately. */
  cp = *ifc->address;
  apply_mask (&cp);
  rn = route_node_get (zebra_if->ipv4_subnets, &cp);

  if ((addr_list = rn->info))
    SET_FLAG (ifc->flags, ZEBRA_IFA_SECONDARY);
  else
    {
      UNSET_FLAG (ifc->flags, ZEBRA_IFA_SECONDARY);
      rn->info = addr_list = list_new ();
      route_lock_node (rn);
    }

  /* Tie address at the tail of address list. */
  listnode_add (addr_list, ifc);
  
  /* Return list element count. */
  return (addr_list->count);
}

/* Untie an interface address from its derived subnet list of addresses. */
int
if_subnet_delete (struct interface *ifp, struct connected *ifc)
{
  struct route_node *rn;
  struct zebra_if *zebra_if;
  struct list *addr_list;

  assert (ifp && ifp->info && ifc);
  zebra_if = ifp->info;

  /* Get address derived subnet node. */
  rn = route_node_lookup (zebra_if->ipv4_subnets, ifc->address);
  if (! (rn && rn->info))
    return -1;
  route_unlock_node (rn);
  
  /* Untie address from subnet's address list. */
  addr_list = rn->info;
  listnode_delete (addr_list, ifc);
  route_unlock_node (rn);

  /* Return list element count, if not empty. */
  if (addr_list->count)
    {
      /* If deleted address is primary, mark subsequent one as such and distribute. */
      if (! CHECK_FLAG (ifc->flags, ZEBRA_IFA_SECONDARY))
	{
	  ifc = listgetdata (listhead (addr_list));
	  zebra_interface_address_delete_update (ifp, ifc);
	  UNSET_FLAG (ifc->flags, ZEBRA_IFA_SECONDARY);
	  zebra_interface_address_add_update (ifp, ifc);
	}
      
      return addr_list->count;
    }
  
  /* Otherwise, free list and route node. */
  list_free (addr_list);
  rn->info = NULL;
  route_unlock_node (rn);

  return 0;
}

/* Wake up configured address if it is not in current kernel
   address. */
static void
if_addr_wakeup (struct interface *ifp)
{
  struct listnode *node, *nnode;
  struct connected *ifc;
  struct prefix *p;
  int ret;

  for (ALL_LIST_ELEMENTS (ifp->connected, node, nnode, ifc))
    {
      p = ifc->address;
	
      if (CHECK_FLAG (ifc->conf, ZEBRA_IFC_CONFIGURED)
	  && ! CHECK_FLAG (ifc->conf, ZEBRA_IFC_REAL))
	{
	  /* Address check. */
	  if (p->family == AF_INET)
	    {
	      if (! if_is_up (ifp))
		{
		  if_set_flags (ifp, IFF_UP | IFF_RUNNING);
		  if_refresh (ifp);
		}

	      ret = if_set_prefix (ifp, ifc);
	      if (ret < 0)
		{
		  zlog_warn ("Can't set interface's address: %s", 
			     safe_strerror(errno));
		  continue;
		}

	      /* Add to subnet chain list. */
	      if_subnet_add (ifp, ifc);

	      SET_FLAG (ifc->conf, ZEBRA_IFC_REAL);

	      zebra_interface_address_add_update (ifp, ifc);

	      if (if_is_operative(ifp))
		connected_up_ipv4 (ifp, ifc);
	    }
#ifdef HAVE_IPV6
	  if (p->family == AF_INET6)
	    {
	      if (! if_is_up (ifp))
		{
		  if_set_flags (ifp, IFF_UP | IFF_RUNNING);
		  if_refresh (ifp);
		}

	      ret = if_prefix_add_ipv6 (ifp, ifc);
	      if (ret < 0)
		{
		  zlog_warn ("Can't set interface's address: %s", 
			     safe_strerror(errno));
		  continue;
		}
	      SET_FLAG (ifc->conf, ZEBRA_IFC_REAL);

	      zebra_interface_address_add_update (ifp, ifc);

	      if (if_is_operative(ifp))
		connected_up_ipv6 (ifp, ifc);
	    }
#endif /* HAVE_IPV6 */
	}
    }
}

/* Handle interface addition */
void
if_add_update (struct interface *ifp)
{
  struct zebra_if *if_data;

  if_data = ifp->info;
  if (if_data->multicast == IF_ZEBRA_MULTICAST_ON)
    if_set_flags (ifp, IFF_MULTICAST);
  else if (if_data->multicast == IF_ZEBRA_MULTICAST_OFF)
    if_unset_flags (ifp, IFF_MULTICAST);

  zebra_interface_add_update (ifp);

  if (! CHECK_FLAG (ifp->status, ZEBRA_INTERFACE_ACTIVE))
    {
      SET_FLAG (ifp->status, ZEBRA_INTERFACE_ACTIVE);

      if_addr_wakeup (ifp);

      if (IS_ZEBRA_DEBUG_KERNEL)
	zlog_debug ("interface %s index %d becomes active.", 
		    ifp->name, ifp->ifindex);
    }
  else
    {
      if (IS_ZEBRA_DEBUG_KERNEL)
	zlog_debug ("interface %s index %d is added.", ifp->name, ifp->ifindex);
    }
}

/* Handle an interface delete event */
void 
if_delete_update (struct interface *ifp)
{
  struct listnode *node;
  struct listnode *next;
  struct listnode *first;
  struct listnode *last;
  struct connected *ifc;
  struct prefix *p;
  struct route_node *rn;
  struct zebra_if *zebra_if;
  struct list *addr_list;

  zebra_if = ifp->info;

  if (if_is_up(ifp))
    {
      zlog_err ("interface %s index %d is still up while being deleted.",
	    ifp->name, ifp->ifindex);
      return;
    }

  /* Mark interface as inactive */
  UNSET_FLAG (ifp->status, ZEBRA_INTERFACE_ACTIVE);
  
  if (IS_ZEBRA_DEBUG_KERNEL)
    zlog_debug ("interface %s index %d is now inactive.",
	       ifp->name, ifp->ifindex);

  /* Delete connected routes from the kernel. */
  if (ifp->connected)
    {
      last = NULL;
      while ((node = (last ? last->next : listhead (ifp->connected))))
	{
	  ifc = listgetdata (node);
	  p = ifc->address;
	  
	  if (p->family == AF_INET)
	    {
	      rn = route_node_lookup (zebra_if->ipv4_subnets, p);
	      route_unlock_node (rn);
	      addr_list = (struct list *) rn->info;
	      
	      /* Remove addresses, secondaries first. */
	      first = listhead (addr_list);
	      for (node = first->next; node || first; node = next)
		{
		  if (! node)
		    {
		      node = first;
		      first = NULL;
		    }
		  next = node->next;

		  ifc = listgetdata (node);
		  p = ifc->address;

		  connected_down_ipv4 (ifp, ifc);

		  zebra_interface_address_delete_update (ifp, ifc);

		  UNSET_FLAG (ifc->conf, ZEBRA_IFC_REAL);

		  /* Remove from subnet chain. */
		  list_delete_node (addr_list, node);
		  route_unlock_node (rn);
		  
		  /* Remove from interface address list (unconditionally). */
		  listnode_delete (ifp->connected, ifc);
	      	  connected_free (ifc);
		}

	      /* Free chain list and respective route node. */
	      list_delete (addr_list);
	      rn->info = NULL;
	      route_unlock_node (rn);
	    }
#ifdef HAVE_IPV6
	  else if (p->family == AF_INET6)
	    {
	      connected_down_ipv6 (ifp, ifc);

	      zebra_interface_address_delete_update (ifp, ifc);

	      UNSET_FLAG (ifc->conf, ZEBRA_IFC_REAL);

	      if (CHECK_FLAG (ifc->conf, ZEBRA_IFC_CONFIGURED))
		last = node;
	      else
		{
		  listnode_delete (ifp->connected, ifc);
		  connected_free (ifc);
		}
	    }
#endif /* HAVE_IPV6 */
	}
    }
  zebra_interface_delete_update (ifp);

  /* Update ifindex after distributing the delete message.  This is in
     case any client needs to have the old value of ifindex available
     while processing the deletion.  Each client daemon is responsible
     for setting ifindex to IFINDEX_INTERNAL after processing the
     interface deletion message. */
  ifp->ifindex = IFINDEX_INTERNAL;
}

/* Interface is up. */
void
if_up (struct interface *ifp)
{
  struct listnode *node;
  struct listnode *next;
  struct connected *ifc;
  struct prefix *p;

  /* Notify the protocol daemons. */
  zebra_interface_up_update (ifp);

  /* Install connected routes to the kernel. */
  if (ifp->connected)
    {
      for (ALL_LIST_ELEMENTS (ifp->connected, node, next, ifc))
	{
	  p = ifc->address;

	  if (p->family == AF_INET)
	    connected_up_ipv4 (ifp, ifc);
#ifdef HAVE_IPV6
	  else if (p->family == AF_INET6)
	    connected_up_ipv6 (ifp, ifc);
#endif /* HAVE_IPV6 */
	}
    }

  /* Examine all static routes. */
  rib_update ();
}

/* Interface goes down.  We have to manage different behavior of based
   OS. */
void
if_down (struct interface *ifp)
{
  struct listnode *node;
  struct listnode *next;
  struct connected *ifc;
  struct prefix *p;

  /* Notify to the protocol daemons. */
  zebra_interface_down_update (ifp);

  /* Delete connected routes from the kernel. */
  if (ifp->connected)
    {
      for (ALL_LIST_ELEMENTS (ifp->connected, node, next, ifc))
	{
	  p = ifc->address;

	  if (p->family == AF_INET)
	    connected_down_ipv4 (ifp, ifc);
#ifdef HAVE_IPV6
	  else if (p->family == AF_INET6)
	    connected_down_ipv6 (ifp, ifc);
#endif /* HAVE_IPV6 */
	}
    }

  /* Examine all static routes which direct to the interface. */
  rib_update ();
}

void
if_refresh (struct interface *ifp)
{
  if (if_is_operative (ifp))
    {
      if_get_flags (ifp);
      if (! if_is_operative (ifp))
	if_down (ifp);
    }
  else
    {
      if_get_flags (ifp);
      if (if_is_operative (ifp))
	if_up (ifp);
    }
}

/* Printout flag information into vty */
static void
if_flag_dump_vty (struct vty *vty, unsigned long flag)
{
  int separator = 0;

#define IFF_OUT_VTY(X, Y) \
  if ((X) && (flag & (X))) \
    { \
      if (separator) \
	vty_out (vty, ","); \
      else \
	separator = 1; \
      vty_out (vty, Y); \
    }

  vty_out (vty, "<");
  IFF_OUT_VTY (IFF_UP, "UP");
  IFF_OUT_VTY (IFF_BROADCAST, "BROADCAST");
  IFF_OUT_VTY (IFF_DEBUG, "DEBUG");
  IFF_OUT_VTY (IFF_LOOPBACK, "LOOPBACK");
  IFF_OUT_VTY (IFF_POINTOPOINT, "POINTOPOINT");
  IFF_OUT_VTY (IFF_NOTRAILERS, "NOTRAILERS");
  IFF_OUT_VTY (IFF_RUNNING, "RUNNING");
  IFF_OUT_VTY (IFF_NOARP, "NOARP");
  IFF_OUT_VTY (IFF_PROMISC, "PROMISC");
  IFF_OUT_VTY (IFF_ALLMULTI, "ALLMULTI");
  IFF_OUT_VTY (IFF_OACTIVE, "OACTIVE");
  IFF_OUT_VTY (IFF_SIMPLEX, "SIMPLEX");
  IFF_OUT_VTY (IFF_LINK0, "LINK0");
  IFF_OUT_VTY (IFF_LINK1, "LINK1");
  IFF_OUT_VTY (IFF_LINK2, "LINK2");
  IFF_OUT_VTY (IFF_MULTICAST, "MULTICAST");
#ifdef SOLARIS_IPV6
  IFF_OUT_VTY (IFF_IPV4, "IFF_IPv4");
  IFF_OUT_VTY (IFF_IPV6, "IFF_IPv6");
#endif /* SOLARIS_IPV6 */
  vty_out (vty, ">");
}

/* Output prefix string to vty. */
static int
prefix_vty_out (struct vty *vty, struct prefix *p)
{
  char str[INET6_ADDRSTRLEN];

  inet_ntop (p->family, &p->u.prefix, str, sizeof (str));
  vty_out (vty, "%s", str);
  return strlen (str);
}

/* Dump if address information to vty. */
static void
connected_dump_vty (struct vty *vty, struct connected *connected)
{
  struct prefix *p;
  struct interface *ifp;

  /* Set interface pointer. */
  ifp = connected->ifp;

  /* Print interface address. */
  p = connected->address;
  vty_out (vty, "  %s ", prefix_family_str (p));
  prefix_vty_out (vty, p);
  vty_out (vty, "/%d", p->prefixlen);

  /* If there is destination address, print it. */
  p = connected->destination;
  if (p)
    {
      if (p->family == AF_INET)
	if (ifp->flags & IFF_BROADCAST)
	  {
	    vty_out (vty, " broadcast ");
	    prefix_vty_out (vty, p);
	  }

      if (ifp->flags & IFF_POINTOPOINT)
	{
	  vty_out (vty, " pointopoint ");
	  prefix_vty_out (vty, p);
	}
    }

  if (CHECK_FLAG (connected->flags, ZEBRA_IFA_SECONDARY))
    vty_out (vty, " secondary");

  if (connected->label)
    vty_out (vty, " %s", connected->label);

  vty_out (vty, "%s", VTY_NEWLINE);
}

#ifdef RTADV
/* Dump interface ND information to vty. */
static void
nd_dump_vty (struct vty *vty, struct interface *ifp)
{
  struct zebra_if *zif;
  struct rtadvconf *rtadv;
  int interval;

  zif = (struct zebra_if *) ifp->info;
  rtadv = &zif->rtadv;

  if (rtadv->AdvSendAdvertisements)
    {
      vty_out (vty, "  ND advertised reachable time is %d milliseconds%s",
	       rtadv->AdvReachableTime, VTY_NEWLINE);
      vty_out (vty, "  ND advertised retransmit interval is %d milliseconds%s",
	       rtadv->AdvRetransTimer, VTY_NEWLINE);
      interval = rtadv->MaxRtrAdvInterval;
      if (interval % 1000)
        vty_out (vty, "  ND router advertisements are sent every "
			"%d milliseconds%s", interval,
		 VTY_NEWLINE);
      else
        vty_out (vty, "  ND router advertisements are sent every "
			"%d seconds%s", interval / 1000,
		 VTY_NEWLINE);
      vty_out (vty, "  ND router advertisements live for %d seconds%s",
	       rtadv->AdvDefaultLifetime, VTY_NEWLINE);
      if (rtadv->AdvManagedFlag)
	vty_out (vty, "  Hosts use DHCP to obtain routable addresses.%s",
		 VTY_NEWLINE);
      else
	vty_out (vty, "  Hosts use stateless autoconfig for addresses.%s",
		 VTY_NEWLINE);
      if (rtadv->AdvHomeAgentFlag)
      	vty_out (vty, "  ND router advertisements with "
				"Home Agent flag bit set.%s",
		 VTY_NEWLINE);
      if (rtadv->AdvIntervalOption)
      	vty_out (vty, "  ND router advertisements with Adv. Interval option.%s",
		 VTY_NEWLINE);
    }
}
#endif /* RTADV */

/* Interface's information print out to vty interface. */
static void
if_dump_vty (struct vty *vty, struct interface *ifp)
{
#ifdef HAVE_SOCKADDR_DL
  struct sockaddr_dl *sdl;
#endif /* HAVE_SOCKADDR_DL */
  struct connected *connected;
  struct listnode *node;
  struct route_node *rn;
  struct zebra_if *zebra_if;

  zebra_if = ifp->info;

  vty_out (vty, "Interface %s is ", ifp->name);
  if (if_is_up(ifp)) {
    vty_out (vty, "up, line protocol ");
    
    if (CHECK_FLAG(ifp->status, ZEBRA_INTERFACE_LINKDETECTION)) {
      if (if_is_running(ifp))
       vty_out (vty, "is up%s", VTY_NEWLINE);
      else
	vty_out (vty, "is down%s", VTY_NEWLINE);
    } else {
      vty_out (vty, "detection is disabled%s", VTY_NEWLINE);
    }
  } else {
    vty_out (vty, "down%s", VTY_NEWLINE);
  }

  if (ifp->desc)
    vty_out (vty, "  Description: %s%s", ifp->desc,
	     VTY_NEWLINE);
  if (ifp->ifindex == IFINDEX_INTERNAL)
    {
      vty_out(vty, "  pseudo interface%s", VTY_NEWLINE);
      return;
    }
  else if (! CHECK_FLAG (ifp->status, ZEBRA_INTERFACE_ACTIVE))
    {
      vty_out(vty, "  index %d inactive interface%s", 
	      ifp->ifindex, 
	      VTY_NEWLINE);
      return;
    }

  vty_out (vty, "  index %d metric %d mtu %d ",
	   ifp->ifindex, ifp->metric, ifp->mtu);
  if_flag_dump_vty (vty, ifp->flags);
#ifdef HAVE_IPV6
  if (ifp->mtu6 != ifp->mtu)
    vty_out (vty, "mtu6 %d ", ifp->mtu6);
#endif 

  vty_out (vty, "%s", VTY_NEWLINE);

  /* Hardware address. */
#ifdef HAVE_SOCKADDR_DL
  sdl = &ifp->sdl;
  if (sdl != NULL && sdl->sdl_alen != 0)
    {
      int i;
      u_char *ptr;

      vty_out (vty, "  HWaddr: ");
      for (i = 0, ptr = (u_char *)LLADDR (sdl); i < sdl->sdl_alen; i++, ptr++)
        vty_out (vty, "%s%02x", i == 0 ? "" : ":", *ptr);
      vty_out (vty, "%s", VTY_NEWLINE);
    }
#else
  if (ifp->hw_addr_len != 0)
    {
      int i;

      vty_out (vty, "  HWaddr: ");
      for (i = 0; i < ifp->hw_addr_len; i++)
	vty_out (vty, "%s%02x", i == 0 ? "" : ":", ifp->hw_addr[i]);
      vty_out (vty, "%s", VTY_NEWLINE);
    }
#endif /* HAVE_SOCKADDR_DL */
  
  /* Bandwidth in kbps */
  if (ifp->bandwidth != 0)
    {
      vty_out(vty, "  bandwidth %u kbps", ifp->bandwidth);
      vty_out(vty, "%s", VTY_NEWLINE);
    }

  for (rn = route_top (zebra_if->ipv4_subnets); rn; rn = route_next (rn))
    {
      if (! rn->info)
	continue;
      
      for (ALL_LIST_ELEMENTS_RO ((struct list *)rn->info, node, connected))
        connected_dump_vty (vty, connected);
    }

  for (ALL_LIST_ELEMENTS_RO (ifp->connected, node, connected))
    {
      if (CHECK_FLAG (connected->conf, ZEBRA_IFC_REAL) &&
	  (connected->address->family == AF_INET6))
	connected_dump_vty (vty, connected);
    }

#ifdef RTADV
  nd_dump_vty (vty, ifp);
#endif /* RTADV */

#ifdef HAVE_PROC_NET_DEV
  /* Statistics print out using proc file system. */
  vty_out (vty, "    %lu input packets (%lu multicast), %lu bytes, "
	   "%lu dropped%s",
	   ifp->stats.rx_packets, ifp->stats.rx_multicast,
	   ifp->stats.rx_bytes, ifp->stats.rx_dropped, VTY_NEWLINE);

  vty_out (vty, "    %lu input errors, %lu length, %lu overrun,"
	   " %lu CRC, %lu frame%s",
	   ifp->stats.rx_errors, ifp->stats.rx_length_errors,
	   ifp->stats.rx_over_errors, ifp->stats.rx_crc_errors,
	   ifp->stats.rx_frame_errors, VTY_NEWLINE);

  vty_out (vty, "    %lu fifo, %lu missed%s", ifp->stats.rx_fifo_errors,
	   ifp->stats.rx_missed_errors, VTY_NEWLINE);

  vty_out (vty, "    %lu output packets, %lu bytes, %lu dropped%s",
	   ifp->stats.tx_packets, ifp->stats.tx_bytes,
	   ifp->stats.tx_dropped, VTY_NEWLINE);

  vty_out (vty, "    %lu output errors, %lu aborted, %lu carrier,"
	   " %lu fifo, %lu heartbeat%s",
	   ifp->stats.tx_errors, ifp->stats.tx_aborted_errors,
	   ifp->stats.tx_carrier_errors, ifp->stats.tx_fifo_errors,
	   ifp->stats.tx_heartbeat_errors, VTY_NEWLINE);

  vty_out (vty, "    %lu window, %lu collisions%s",
	   ifp->stats.tx_window_errors, ifp->stats.collisions, VTY_NEWLINE);
#endif /* HAVE_PROC_NET_DEV */

#ifdef HAVE_NET_RT_IFLIST
#if defined (__bsdi__) || defined (__NetBSD__)
  /* Statistics print out using sysctl (). */
  vty_out (vty, "    input packets %qu, bytes %qu, dropped %qu,"
	   " multicast packets %qu%s",
	   ifp->stats.ifi_ipackets, ifp->stats.ifi_ibytes,
	   ifp->stats.ifi_iqdrops, ifp->stats.ifi_imcasts,
	   VTY_NEWLINE);

  vty_out (vty, "    input errors %qu%s",
	   ifp->stats.ifi_ierrors, VTY_NEWLINE);

  vty_out (vty, "    output packets %qu, bytes %qu, multicast packets %qu%s",
	   ifp->stats.ifi_opackets, ifp->stats.ifi_obytes,
	   ifp->stats.ifi_omcasts, VTY_NEWLINE);

  vty_out (vty, "    output errors %qu%s",
	   ifp->stats.ifi_oerrors, VTY_NEWLINE);

  vty_out (vty, "    collisions %qu%s",
	   ifp->stats.ifi_collisions, VTY_NEWLINE);
#else
  /* Statistics print out using sysctl (). */
  vty_out (vty, "    input packets %lu, bytes %lu, dropped %lu,"
	   " multicast packets %lu%s",
	   ifp->stats.ifi_ipackets, ifp->stats.ifi_ibytes,
	   ifp->stats.ifi_iqdrops, ifp->stats.ifi_imcasts,
	   VTY_NEWLINE);

  vty_out (vty, "    input errors %lu%s",
	   ifp->stats.ifi_ierrors, VTY_NEWLINE);

  vty_out (vty, "    output packets %lu, bytes %lu, multicast packets %lu%s",
	   ifp->stats.ifi_opackets, ifp->stats.ifi_obytes,
	   ifp->stats.ifi_omcasts, VTY_NEWLINE);

  vty_out (vty, "    output errors %lu%s",
	   ifp->stats.ifi_oerrors, VTY_NEWLINE);

  vty_out (vty, "    collisions %lu%s",
	   ifp->stats.ifi_collisions, VTY_NEWLINE);
#endif /* __bsdi__ || __NetBSD__ */
#endif /* HAVE_NET_RT_IFLIST */
}

/* Check supported address family. */
static int
if_supported_family (int family)
{
  if (family == AF_INET)
    return 1;
#ifdef HAVE_IPV6
  if (family == AF_INET6)
    return 1;
#endif /* HAVE_IPV6 */
  return 0;
}

/* Wrapper hook point for zebra daemon so that ifindex can be set 
 * DEFUN macro not used as extract.pl HAS to ignore this
 * See also interface_cmd in lib/if.c
 */ 
DEFUN_NOSH (zebra_interface,
	    zebra_interface_cmd,
	    "interface IFNAME",
	    "Select an interface to configure\n"
	    "Interface's name\n")
{
  int ret;
  struct interface * ifp;
  
  /* Call lib interface() */
  if ((ret = interface_cmd.func (self, vty, argc, argv)) != CMD_SUCCESS)
    return ret;

  ifp = vty->index;  

  if (ifp->ifindex == IFINDEX_INTERNAL)
    /* Is this really necessary?  Shouldn't status be initialized to 0
       in that case? */
    UNSET_FLAG (ifp->status, ZEBRA_INTERFACE_ACTIVE);

  return ret;
}

struct cmd_node interface_node =
{
  INTERFACE_NODE,
  "%s(config-if)# ",
  1
};

/* Show all or specified interface to vty. */
DEFUN (show_interface, show_interface_cmd,
       "show interface [IFNAME]",  
       SHOW_STR
       "Interface status and configuration\n"
       "Inteface name\n")
{
  struct listnode *node;
  struct interface *ifp;
  
#ifdef HAVE_PROC_NET_DEV
  /* If system has interface statistics via proc file system, update
     statistics. */
  ifstat_update_proc ();
#endif /* HAVE_PROC_NET_DEV */
#ifdef HAVE_NET_RT_IFLIST
  ifstat_update_sysctl ();
#endif /* HAVE_NET_RT_IFLIST */

  /* Specified interface print. */
  if (argc != 0)
    {
      ifp = if_lookup_by_name (argv[0]);
      if (ifp == NULL) 
	{
	  vty_out (vty, "%% Can't find interface %s%s", argv[0],
		   VTY_NEWLINE);
	  return CMD_WARNING;
	}
      if_dump_vty (vty, ifp);
      return CMD_SUCCESS;
    }

  /* All interface print. */
  for (ALL_LIST_ELEMENTS_RO (iflist, node, ifp))
    if_dump_vty (vty, ifp);

  return CMD_SUCCESS;
}

DEFUN (show_interface_desc,
       show_interface_desc_cmd,
       "show interface description",
       SHOW_STR
       "Interface status and configuration\n"
       "Interface description\n")
{
  struct listnode *node;
  struct interface *ifp;

  vty_out (vty, "Interface       Status  Protocol  Description%s", VTY_NEWLINE);
  for (ALL_LIST_ELEMENTS_RO (iflist, node, ifp))
    {
      int len;

      len = vty_out (vty, "%s", ifp->name);
      vty_out (vty, "%*s", (16 - len), " ");
      
      if (if_is_up(ifp))
	{
	  vty_out (vty, "up      ");
	  if (CHECK_FLAG(ifp->status, ZEBRA_INTERFACE_LINKDETECTION))
	    {
	      if (if_is_running(ifp))
		vty_out (vty, "up        ");
	      else
		vty_out (vty, "down      ");
	    }
	  else
	    {
	      vty_out (vty, "unknown   ");
	    }
	}
      else
	{
	  vty_out (vty, "down    down      ");
	}

      if (ifp->desc)
	vty_out (vty, "%s", ifp->desc);
      vty_out (vty, "%s", VTY_NEWLINE);
    }
  return CMD_SUCCESS;
}

DEFUN (multicast,
       multicast_cmd,
       "multicast",
       "Set multicast flag to interface\n")
{
  int ret;
  struct interface *ifp;
  struct zebra_if *if_data;

  ifp = (struct interface *) vty->index;
  if (CHECK_FLAG (ifp->status, ZEBRA_INTERFACE_ACTIVE))
    {
      ret = if_set_flags (ifp, IFF_MULTICAST);
      if (ret < 0)
	{
	  vty_out (vty, "Can't set multicast flag%s", VTY_NEWLINE);
	  return CMD_WARNING;
	}
      if_refresh (ifp);
    }
  if_data = ifp->info;
  if_data->multicast = IF_ZEBRA_MULTICAST_ON;

  return CMD_SUCCESS;
}

DEFUN (no_multicast,
       no_multicast_cmd,
       "no multicast",
       NO_STR
       "Unset multicast flag to interface\n")
{
  int ret;
  struct interface *ifp;
  struct zebra_if *if_data;

  ifp = (struct interface *) vty->index;
  if (CHECK_FLAG (ifp->status, ZEBRA_INTERFACE_ACTIVE))
    {
      ret = if_unset_flags (ifp, IFF_MULTICAST);
      if (ret < 0)
	{
	  vty_out (vty, "Can't unset multicast flag%s", VTY_NEWLINE);
	  return CMD_WARNING;
	}
      if_refresh (ifp);
    }
  if_data = ifp->info;
  if_data->multicast = IF_ZEBRA_MULTICAST_OFF;

  return CMD_SUCCESS;
}

DEFUN (linkdetect,
       linkdetect_cmd,
       "link-detect",
       "Enable link detection on interface\n")
{
  struct interface *ifp;
  int if_was_operative;
  
  ifp = (struct interface *) vty->index;
  if_was_operative = if_is_operative(ifp);
  SET_FLAG(ifp->status, ZEBRA_INTERFACE_LINKDETECTION);

  /* When linkdetection is enabled, if might come down */
  if (!if_is_operative(ifp) && if_was_operative) if_down(ifp);

  /* FIXME: Will defer status change forwarding if interface
     does not come down! */

  return CMD_SUCCESS;
}


DEFUN (no_linkdetect,
       no_linkdetect_cmd,
       "no link-detect",
       NO_STR
       "Disable link detection on interface\n")
{
  struct interface *ifp;
  int if_was_operative;

  ifp = (struct interface *) vty->index;
  if_was_operative = if_is_operative(ifp);
  UNSET_FLAG(ifp->status, ZEBRA_INTERFACE_LINKDETECTION);
  
  /* Interface may come up after disabling link detection */
  if (if_is_operative(ifp) && !if_was_operative) if_up(ifp);

  /* FIXME: see linkdetect_cmd */

  return CMD_SUCCESS;
}

DEFUN (shutdown_if,
       shutdown_if_cmd,
       "shutdown",
       "Shutdown the selected interface\n")
{
  int ret;
  struct interface *ifp;
  struct zebra_if *if_data;

  ifp = (struct interface *) vty->index;
  ret = if_unset_flags (ifp, IFF_UP);
  if (ret < 0)
    {
      vty_out (vty, "Can't shutdown interface%s", VTY_NEWLINE);
      return CMD_WARNING;
    }
  if_refresh (ifp);
  if_data = ifp->info;
  if_data->shutdown = IF_ZEBRA_SHUTDOWN_ON;

  return CMD_SUCCESS;
}

DEFUN (no_shutdown_if,
       no_shutdown_if_cmd,
       "no shutdown",
       NO_STR
       "Shutdown the selected interface\n")
{
  int ret;
  struct interface *ifp;
  struct zebra_if *if_data;

  ifp = (struct interface *) vty->index;
  ret = if_set_flags (ifp, IFF_UP | IFF_RUNNING);
  if (ret < 0)
    {
      vty_out (vty, "Can't up interface%s", VTY_NEWLINE);
      return CMD_WARNING;
    }
  if_refresh (ifp);
  if_data = ifp->info;
  if_data->shutdown = IF_ZEBRA_SHUTDOWN_OFF;

  return CMD_SUCCESS;
}

DEFUN (bandwidth_if,
       bandwidth_if_cmd,
       "bandwidth <1-10000000>",
       "Set bandwidth informational parameter\n"
       "Bandwidth in kilobits\n")
{
  struct interface *ifp;   
  unsigned int bandwidth;
  
  ifp = (struct interface *) vty->index;
  bandwidth = strtol(argv[0], NULL, 10);

  /* bandwidth range is <1-10000000> */
  if (bandwidth < 1 || bandwidth > 10000000)
    {
      vty_out (vty, "Bandwidth is invalid%s", VTY_NEWLINE);
      return CMD_WARNING;
    }
  
  ifp->bandwidth = bandwidth;

  /* force protocols to recalculate routes due to cost change */
  if (if_is_operative (ifp))
    zebra_interface_up_update (ifp);
  
  return CMD_SUCCESS;
}

DEFUN (no_bandwidth_if,
       no_bandwidth_if_cmd,
       "no bandwidth",
       NO_STR
       "Set bandwidth informational parameter\n")
{
  struct interface *ifp;   
  
  ifp = (struct interface *) vty->index;

  ifp->bandwidth = 0;
  
  /* force protocols to recalculate routes due to cost change */
  if (if_is_operative (ifp))
    zebra_interface_up_update (ifp);

  return CMD_SUCCESS;
}

ALIAS (no_bandwidth_if,
       no_bandwidth_if_val_cmd,
       "no bandwidth <1-10000000>",
       NO_STR
       "Set bandwidth informational parameter\n"
       "Bandwidth in kilobits\n")

static int
ip_address_install (struct vty *vty, struct interface *ifp,
		    const char *addr_str, const char *peer_str,
		    const char *label)
{
  struct prefix_ipv4 cp;
  struct connected *ifc;
  struct prefix_ipv4 *p;
  int ret;

  ret = str2prefix_ipv4 (addr_str, &cp);
  if (ret <= 0)
    {
      vty_out (vty, "%% Malformed address %s", VTY_NEWLINE);
      return CMD_WARNING;
    }

  ifc = connected_check (ifp, (struct prefix *) &cp);
  if (! ifc)
    {
      ifc = connected_new ();
      ifc->ifp = ifp;

      /* Address. */
      p = prefix_ipv4_new ();
      *p = cp;
      ifc->address = (struct prefix *) p;

      /* Broadcast. */
      if (p->prefixlen <= IPV4_MAX_PREFIXLEN-2)
	{
	  p = prefix_ipv4_new ();
	  *p = cp;
	  p->prefix.s_addr = ipv4_broadcast_addr(p->prefix.s_addr,p->prefixlen);
	  ifc->destination = (struct prefix *) p;
	}

      /* Label. */
      if (label)
	ifc->label = strdup (label);

      /* Add to linked list. */
      listnode_add (ifp->connected, ifc);
    }

  /* This address is configured from zebra. */
  if (! CHECK_FLAG (ifc->conf, ZEBRA_IFC_CONFIGURED))
    SET_FLAG (ifc->conf, ZEBRA_IFC_CONFIGURED);

  /* In case of this route need to install kernel. */
  if (! CHECK_FLAG (ifc->conf, ZEBRA_IFC_REAL)
      && CHECK_FLAG (ifp->status, ZEBRA_INTERFACE_ACTIVE))
    {
      /* Some system need to up the interface to set IP address. */
      if (! if_is_up (ifp))
	{
	  if_set_flags (ifp, IFF_UP | IFF_RUNNING);
	  if_refresh (ifp);
	}

      ret = if_set_prefix (ifp, ifc);
      if (ret < 0)
	{
	  vty_out (vty, "%% Can't set interface IP address: %s.%s", 
		   safe_strerror(errno), VTY_NEWLINE);
	  return CMD_WARNING;
	}

      /* Add to subnet chain list (while marking secondary attribute). */
      if_subnet_add (ifp, ifc);

      /* IP address propery set. */
      SET_FLAG (ifc->conf, ZEBRA_IFC_REAL);

      /* Update interface address information to protocol daemon. */
      zebra_interface_address_add_update (ifp, ifc);

      /* If interface is up register connected route. */
      if (if_is_operative(ifp))
	connected_up_ipv4 (ifp, ifc);
    }

  return CMD_SUCCESS;
}

static int
ip_address_uninstall (struct vty *vty, struct interface *ifp,
		      const char *addr_str, const char *peer_str,
		      const char *label)
{
  struct prefix_ipv4 cp;
  struct connected *ifc;
  int ret;

  /* Convert to prefix structure. */
  ret = str2prefix_ipv4 (addr_str, &cp);
  if (ret <= 0)
    {
      vty_out (vty, "%% Malformed address %s", VTY_NEWLINE);
      return CMD_WARNING;
    }

  /* Check current interface address. */
  ifc = connected_check (ifp, (struct prefix *) &cp);
  if (! ifc)
    {
      vty_out (vty, "%% Can't find address%s", VTY_NEWLINE);
      return CMD_WARNING;
    }

  /* This is not configured address. */
  if (! CHECK_FLAG (ifc->conf, ZEBRA_IFC_CONFIGURED))
    return CMD_WARNING;

  /* This is not real address or interface is not active. */
  if (! CHECK_FLAG (ifc->conf, ZEBRA_IFC_REAL)
      || ! CHECK_FLAG (ifp->status, ZEBRA_INTERFACE_ACTIVE))
    {
      listnode_delete (ifp->connected, ifc);
      connected_free (ifc);
      return CMD_WARNING;
    }

  /* This is real route. */
  ret = if_unset_prefix (ifp, ifc);
  if (ret < 0)
    {
      vty_out (vty, "%% Can't unset interface IP address: %s.%s", 
	       safe_strerror(errno), VTY_NEWLINE);
      return CMD_WARNING;
    }

#if 0
  /* Redistribute this information. */
  zebra_interface_address_delete_update (ifp, ifc);

  /* Remove connected route. */
  connected_down_ipv4 (ifp, ifc);

  /* Free address information. */
  listnode_delete (ifp->connected, ifc);
  connected_free (ifc);
#endif

  return CMD_SUCCESS;
}

DEFUN (ip_address,
       ip_address_cmd,
       "ip address A.B.C.D/M",
       "Interface Internet Protocol config commands\n"
       "Set the IP address of an interface\n"
       "IP address (e.g. 10.0.0.1/8)\n")
{
  return ip_address_install (vty, vty->index, argv[0], NULL, NULL);
}

DEFUN (no_ip_address,
       no_ip_address_cmd,
       "no ip address A.B.C.D/M",
       NO_STR
       "Interface Internet Protocol config commands\n"
       "Set the IP address of an interface\n"
       "IP Address (e.g. 10.0.0.1/8)")
{
  return ip_address_uninstall (vty, vty->index, argv[0], NULL, NULL);
}

#ifdef HAVE_NETLINK
DEFUN (ip_address_label,
       ip_address_label_cmd,
       "ip address A.B.C.D/M label LINE",
       "Interface Internet Protocol config commands\n"
       "Set the IP address of an interface\n"
       "IP address (e.g. 10.0.0.1/8)\n"
       "Label of this address\n"
       "Label\n")
{
  return ip_address_install (vty, vty->index, argv[0], NULL, argv[1]);
}

DEFUN (no_ip_address_label,
       no_ip_address_label_cmd,
       "no ip address A.B.C.D/M label LINE",
       NO_STR
       "Interface Internet Protocol config commands\n"
       "Set the IP address of an interface\n"
       "IP address (e.g. 10.0.0.1/8)\n"
       "Label of this address\n"
       "Label\n")
{
  return ip_address_uninstall (vty, vty->index, argv[0], NULL, argv[1]);
}
#endif /* HAVE_NETLINK */

#ifdef HAVE_IPV6
static int
ipv6_address_install (struct vty *vty, struct interface *ifp,
		      const char *addr_str, const char *peer_str,
		      const char *label, int secondary)
{
  struct prefix_ipv6 cp;
  struct connected *ifc;
  struct prefix_ipv6 *p;
  int ret;

  ret = str2prefix_ipv6 (addr_str, &cp);
  if (ret <= 0)
    {
      vty_out (vty, "%% Malformed address %s", VTY_NEWLINE);
      return CMD_WARNING;
    }

  ifc = connected_check (ifp, (struct prefix *) &cp);
  if (! ifc)
    {
      ifc = connected_new ();
      ifc->ifp = ifp;

      /* Address. */
      p = prefix_ipv6_new ();
      *p = cp;
      ifc->address = (struct prefix *) p;

      /* Secondary. */
      if (secondary)
	SET_FLAG (ifc->flags, ZEBRA_IFA_SECONDARY);

      /* Label. */
      if (label)
	ifc->label = strdup (label);

      /* Add to linked list. */
      listnode_add (ifp->connected, ifc);
    }

  /* This address is configured from zebra. */
  if (! CHECK_FLAG (ifc->conf, ZEBRA_IFC_CONFIGURED))
    SET_FLAG (ifc->conf, ZEBRA_IFC_CONFIGURED);

  /* In case of this route need to install kernel. */
  if (! CHECK_FLAG (ifc->conf, ZEBRA_IFC_REAL)
      && CHECK_FLAG (ifp->status, ZEBRA_INTERFACE_ACTIVE))
    {
      /* Some system need to up the interface to set IP address. */
      if (! if_is_up (ifp))
	{
	  if_set_flags (ifp, IFF_UP | IFF_RUNNING);
	  if_refresh (ifp);
	}

      ret = if_prefix_add_ipv6 (ifp, ifc);

      if (ret < 0)
	{
	  vty_out (vty, "%% Can't set interface IP address: %s.%s", 
		   safe_strerror(errno), VTY_NEWLINE);
	  return CMD_WARNING;
	}

      /* IP address propery set. */
      SET_FLAG (ifc->conf, ZEBRA_IFC_REAL);

      /* Update interface address information to protocol daemon. */
      zebra_interface_address_add_update (ifp, ifc);

      /* If interface is up register connected route. */
      if (if_is_operative(ifp))
	connected_up_ipv6 (ifp, ifc);
    }

  return CMD_SUCCESS;
}

static int
ipv6_address_uninstall (struct vty *vty, struct interface *ifp,
			const char *addr_str, const char *peer_str,
			const char *label, int secondry)
{
  struct prefix_ipv6 cp;
  struct connected *ifc;
  int ret;

  /* Convert to prefix structure. */
  ret = str2prefix_ipv6 (addr_str, &cp);
  if (ret <= 0)
    {
      vty_out (vty, "%% Malformed address %s", VTY_NEWLINE);
      return CMD_WARNING;
    }

  /* Check current interface address. */
  ifc = connected_check (ifp, (struct prefix *) &cp);
  if (! ifc)
    {
      vty_out (vty, "%% Can't find address%s", VTY_NEWLINE);
      return CMD_WARNING;
    }

  /* This is not configured address. */
  if (! CHECK_FLAG (ifc->conf, ZEBRA_IFC_CONFIGURED))
    return CMD_WARNING;

  /* This is not real address or interface is not active. */
  if (! CHECK_FLAG (ifc->conf, ZEBRA_IFC_REAL)
      || ! CHECK_FLAG (ifp->status, ZEBRA_INTERFACE_ACTIVE))
    {
      listnode_delete (ifp->connected, ifc);
      connected_free (ifc);
      return CMD_WARNING;
    }

  /* This is real route. */
  ret = if_prefix_delete_ipv6 (ifp, ifc);
  if (ret < 0)
    {
      vty_out (vty, "%% Can't unset interface IP address: %s.%s", 
	       safe_strerror(errno), VTY_NEWLINE);
      return CMD_WARNING;
    }

  /* Redistribute this information. */
  zebra_interface_address_delete_update (ifp, ifc);

  /* Remove connected route. */
  connected_down_ipv6 (ifp, ifc);

  /* Free address information. */
  listnode_delete (ifp->connected, ifc);
  connected_free (ifc);

  return CMD_SUCCESS;
}

DEFUN (ipv6_address,
       ipv6_address_cmd,
       "ipv6 address X:X::X:X/M",
       "Interface IPv6 config commands\n"
       "Set the IP address of an interface\n"
       "IPv6 address (e.g. 3ffe:506::1/48)\n")
{
  return ipv6_address_install (vty, vty->index, argv[0], NULL, NULL, 0);
}

DEFUN (no_ipv6_address,
       no_ipv6_address_cmd,
       "no ipv6 address X:X::X:X/M",
       NO_STR
       "Interface IPv6 config commands\n"
       "Set the IP address of an interface\n"
       "IPv6 address (e.g. 3ffe:506::1/48)\n")
{
  return ipv6_address_uninstall (vty, vty->index, argv[0], NULL, NULL, 0);
}
#endif /* HAVE_IPV6 */

static int
if_config_write (struct vty *vty)
{
  struct listnode *node;
  struct interface *ifp;
  char buf[BUFSIZ];

  for (ALL_LIST_ELEMENTS_RO (iflist, node, ifp))
    {
      struct zebra_if *if_data;
      struct listnode *addrnode;
      struct connected *ifc;
      struct prefix *p;

      if_data = ifp->info;
      
      vty_out (vty, "interface %s%s", ifp->name,
	       VTY_NEWLINE);

      if (ifp->desc)
	vty_out (vty, " description %s%s", ifp->desc,
		 VTY_NEWLINE);

      /* Assign bandwidth here to avoid unnecessary interface flap
	 while processing config script */
      if (ifp->bandwidth != 0)
	vty_out(vty, " bandwidth %u%s", ifp->bandwidth, VTY_NEWLINE); 

      if (CHECK_FLAG(ifp->status, ZEBRA_INTERFACE_LINKDETECTION))
	vty_out(vty, " link-detect%s", VTY_NEWLINE);

      for (ALL_LIST_ELEMENTS_RO (ifp->connected, addrnode, ifc))
	  {
	    if (CHECK_FLAG (ifc->conf, ZEBRA_IFC_CONFIGURED))
	      {
		p = ifc->address;
		vty_out (vty, " ip%s address %s/%d",
			 p->family == AF_INET ? "" : "v6",
			 inet_ntop (p->family, &p->u.prefix, buf, BUFSIZ),
			 p->prefixlen);

		if (ifc->label)
		  vty_out (vty, " label %s", ifc->label);

		vty_out (vty, "%s", VTY_NEWLINE);
	      }
	  }

      if (if_data)
	{
	  if (if_data->shutdown == IF_ZEBRA_SHUTDOWN_ON)
	    vty_out (vty, " shutdown%s", VTY_NEWLINE);

	  if (if_data->multicast != IF_ZEBRA_MULTICAST_UNSPEC)
	    vty_out (vty, " %smulticast%s",
		     if_data->multicast == IF_ZEBRA_MULTICAST_ON ? "" : "no ",
		     VTY_NEWLINE);
	}

#ifdef RTADV
      rtadv_config_write (vty, ifp);
#endif /* RTADV */

#ifdef HAVE_IRDP
      irdp_config_write (vty, ifp);
#endif /* IRDP */

      vty_out (vty, "!%s", VTY_NEWLINE);
    }
  return 0;
}

/* Allocate and initialize interface vector. */
void
zebra_if_init (void)
{
  /* Initialize interface and new hook. */
  if_init ();
  if_add_hook (IF_NEW_HOOK, if_zebra_new_hook);
  if_add_hook (IF_DELETE_HOOK, if_zebra_delete_hook);
  
  /* Install configuration write function. */
  install_node (&interface_node, if_config_write);

  install_element (VIEW_NODE, &show_interface_cmd);
  install_element (ENABLE_NODE, &show_interface_cmd);
  install_element (ENABLE_NODE, &show_interface_desc_cmd);
  install_element (CONFIG_NODE, &zebra_interface_cmd);
  install_element (CONFIG_NODE, &no_interface_cmd);
  install_default (INTERFACE_NODE);
  install_element (INTERFACE_NODE, &interface_desc_cmd);
  install_element (INTERFACE_NODE, &no_interface_desc_cmd);
  install_element (INTERFACE_NODE, &multicast_cmd);
  install_element (INTERFACE_NODE, &no_multicast_cmd);
  install_element (INTERFACE_NODE, &linkdetect_cmd);
  install_element (INTERFACE_NODE, &no_linkdetect_cmd);
  install_element (INTERFACE_NODE, &shutdown_if_cmd);
  install_element (INTERFACE_NODE, &no_shutdown_if_cmd);
  install_element (INTERFACE_NODE, &bandwidth_if_cmd);
  install_element (INTERFACE_NODE, &no_bandwidth_if_cmd);
  install_element (INTERFACE_NODE, &no_bandwidth_if_val_cmd);
  install_element (INTERFACE_NODE, &ip_address_cmd);
  install_element (INTERFACE_NODE, &no_ip_address_cmd);
#ifdef HAVE_IPV6
  install_element (INTERFACE_NODE, &ipv6_address_cmd);
  install_element (INTERFACE_NODE, &no_ipv6_address_cmd);
#endif /* HAVE_IPV6 */
#ifdef HAVE_NETLINK
  install_element (INTERFACE_NODE, &ip_address_label_cmd);
  install_element (INTERFACE_NODE, &no_ip_address_label_cmd);
#endif /* HAVE_NETLINK */
}