diff --git a/ospfd/ospf_abr.h b/ospfd/ospf_abr.h
new file mode 100644
index 0000000..3b385c3
--- /dev/null
+++ b/ospfd/ospf_abr.h
@@ -0,0 +1,84 @@
+/*
+ * OSPF ABR functions.
+ * Copyright (C) 1999 Alex Zinin
+ *
+ * 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.
+ */
+
+#ifndef _ZEBRA_OSPF_ABR_H
+#define _ZEBRA_OSPF_ABR_H
+
+#define OSPF_ABR_TASK_DELAY 	7
+
+#define OSPF_AREA_RANGE_ADVERTISE	(1 << 0)
+#define OSPF_AREA_RANGE_SUBSTITUTE	(1 << 1)
+
+/* Area range. */
+struct ospf_area_range
+{
+  /* Area range address. */
+  struct in_addr addr;
+
+  /* Area range masklen. */
+  u_char masklen;
+
+  /* Flags. */
+  u_char flags;
+
+  /* Number of more specific prefixes. */
+  int specifics;
+
+  /* Addr and masklen to substitute. */
+  struct in_addr subst_addr;
+  u_char subst_masklen;
+
+  /* Range cost. */
+  u_int32_t cost;
+
+  /* Configured range cost. */
+  u_int32_t cost_config;
+#define OSPF_AREA_RANGE_COST_UNSPEC	-1
+};
+
+/* Prototypes. */
+struct ospf_area_range *ospf_area_range_lookup (struct ospf_area *,
+						struct prefix_ipv4 *);
+struct ospf_area_range *ospf_some_area_range_match (struct prefix_ipv4 *);
+struct ospf_area_range *ospf_area_range_lookup_next (struct ospf_area *,
+						     struct in_addr *, int);
+int ospf_area_range_set (struct ospf *, struct in_addr, struct prefix_ipv4 *,
+			 int);
+int ospf_area_range_cost_set (struct ospf *, struct in_addr,
+			      struct prefix_ipv4 *, u_int32_t);
+int ospf_area_range_unset (struct ospf *, struct in_addr,
+			   struct prefix_ipv4 *);
+int ospf_area_range_substitute_set (struct ospf *, struct in_addr,
+				    struct prefix_ipv4 *,
+				    struct prefix_ipv4 *);
+int ospf_area_range_substitute_unset (struct ospf *, struct in_addr,
+				      struct prefix_ipv4 *);
+struct ospf_area_range *ospf_area_range_match_any (struct ospf *,
+						   struct prefix_ipv4 *);
+int ospf_area_range_active (struct ospf_area_range *);
+int ospf_act_bb_connection ();
+
+void ospf_check_abr_status ();
+void ospf_abr_task ();
+void ospf_schedule_abr_task ();
+
+#endif /* _ZEBRA_OSPF_ABR_H */