diff --git a/zebra/interface.h b/zebra/interface.h
new file mode 100644
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--- /dev/null
+++ b/zebra/interface.h
@@ -0,0 +1,180 @@
+/* Interface function header.
+ * Copyright (C) 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.  
+ */
+
+/* For interface multicast configuration. */
+#define IF_ZEBRA_MULTICAST_UNSPEC 0
+#define IF_ZEBRA_MULTICAST_ON     1
+#define IF_ZEBRA_MULTICAST_OFF    2
+
+/* For interface shutdown configuration. */
+#define IF_ZEBRA_SHUTDOWN_UNSPEC 0
+#define IF_ZEBRA_SHUTDOWN_ON     1
+#define IF_ZEBRA_SHUTDOWN_OFF    2
+
+/* Router advertisement feature. */
+#if (defined(LINUX_IPV6) && (defined(__GLIBC__) && __GLIBC__ >= 2 && __GLIBC_MINOR__ >= 1)) || defined(KAME)
+#define RTADV
+#endif
+
+#ifdef RTADV
+/* Router advertisement parameter.  From RFC2461. */
+struct rtadvconf
+{
+  /* A flag indicating whether or not the router sends periodic Router
+     Advertisements and responds to Router Solicitations.
+     Default: FALSE */
+  int AdvSendAdvertisements;
+
+  /* The maximum time allowed between sending unsolicited multicast
+     Router Advertisements from the interface, in seconds.  MUST be no
+     less than 4 seconds and no greater than 1800 seconds. 
+
+     Default: 600 seconds */
+  int MaxRtrAdvInterval;
+#define RTADV_MAX_RTR_ADV_INTERVAL 600
+
+  /* The minimum time allowed between sending unsolicited multicast
+     Router Advertisements from the interface, in seconds.  MUST be no
+     less than 3 seconds and no greater than .75 * MaxRtrAdvInterval.
+
+     Default: 0.33 * MaxRtrAdvInterval */
+  int MinRtrAdvInterval;
+#define RTADV_MIN_RTR_ADV_INTERVAL (0.33 * RTADV_MAX_RTR_ADV_INTERVAL)
+
+  /* Unsolicited Router Advertisements' interval timer. */
+  int AdvIntervalTimer;
+
+  /* The TRUE/FALSE value to be placed in the "Managed address
+     configuration" flag field in the Router Advertisement.  See
+     [ADDRCONF].
+ 
+     Default: FALSE */
+  int AdvManagedFlag;
+
+
+  /* The TRUE/FALSE value to be placed in the "Other stateful
+     configuration" flag field in the Router Advertisement.  See
+     [ADDRCONF].
+
+     Default: FALSE */
+  int AdvOtherConfigFlag;
+
+  /* The value to be placed in MTU options sent by the router.  A
+     value of zero indicates that no MTU options are sent.
+
+     Default: 0 */
+  int AdvLinkMTU;
+
+
+  /* The value to be placed in the Reachable Time field in the Router
+     Advertisement messages sent by the router.  The value zero means
+     unspecified (by this router).  MUST be no greater than 3,600,000
+     milliseconds (1 hour).
+
+     Default: 0 */
+  u_int32_t AdvReachableTime;
+#define RTADV_MAX_REACHABLE_TIME 3600000
+
+
+  /* The value to be placed in the Retrans Timer field in the Router
+     Advertisement messages sent by the router.  The value zero means
+     unspecified (by this router).
+
+     Default: 0 */
+  int AdvRetransTimer;
+
+  /* The default value to be placed in the Cur Hop Limit field in the
+     Router Advertisement messages sent by the router.  The value
+     should be set to that current diameter of the Internet.  The
+     value zero means unspecified (by this router).
+
+     Default: The value specified in the "Assigned Numbers" RFC
+     [ASSIGNED] that was in effect at the time of implementation. */
+  int AdvCurHopLimit;
+
+  /* The value to be placed in the Router Lifetime field of Router
+     Advertisements sent from the interface, in seconds.  MUST be
+     either zero or between MaxRtrAdvInterval and 9000 seconds.  A
+     value of zero indicates that the router is not to be used as a
+     default router.
+
+     Default: 3 * MaxRtrAdvInterval */
+  int AdvDefaultLifetime;
+#define RTADV_ADV_DEFAULT_LIFETIME (3 * RTADV_MAX_RTR_ADV_INTERVAL)
+
+
+  /* A list of prefixes to be placed in Prefix Information options in
+     Router Advertisement messages sent from the interface.
+
+     Default: all prefixes that the router advertises via routing
+     protocols as being on-link for the interface from which the
+     advertisement is sent. The link-local prefix SHOULD NOT be
+     included in the list of advertised prefixes. */
+  list AdvPrefixList;
+};
+
+#endif /* RTADV */
+
+/* `zebra' daemon local interface structure. */
+struct zebra_if
+{
+  /* Shutdown configuration. */
+  u_char shutdown;
+
+  /* Multicast configuration. */
+  u_char multicast;
+
+  /* Router advertise configuration. */
+  u_char rtadv_enable;
+
+  /* Interface's address. */
+  list address;
+
+#ifdef RTADV
+  struct rtadvconf rtadv;
+#endif /* RTADV */
+};
+
+void if_delete_update (struct interface *ifp);
+void if_add_update (struct interface *ifp);
+void if_up (struct interface *);
+void if_down (struct interface *);
+void if_refresh (struct interface *);
+void zebra_interface_up_update (struct interface *ifp);
+void zebra_interface_down_update (struct interface *ifp);
+
+#ifdef HAVE_PROC_NET_DEV
+int ifstat_update_proc ();
+#endif /* HAVE_PROC_NET_DEV */
+#ifdef HAVE_NET_RT_IFLIST
+void ifstat_update_sysctl ();
+
+#endif /* HAVE_NET_RT_IFLIST */
+#ifdef HAVE_PROC_NET_DEV
+int interface_list_proc ();
+#endif /* HAVE_PROC_NET_DEV */
+#ifdef HAVE_PROC_NET_IF_INET6
+int ifaddr_proc_ipv6 ();
+#endif /* HAVE_PROC_NET_IF_INET6 */
+
+#ifdef BSDI
+int if_kvm_get_mtu (struct interface *);
+#endif /* BSDI */