diff --git a/ospfd/ospf_api.h b/ospfd/ospf_api.h
new file mode 100644
index 0000000..e786761
--- /dev/null
+++ b/ospfd/ospf_api.h
@@ -0,0 +1,357 @@
+/*
+ * API message handling module for OSPF daemon and client.
+ * Copyright (C) 2001, 2002 Ralph Keller
+ *
+ * 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.
+ */
+
+
+/* This file is used both by the OSPFd and client applications to
+   define message formats used for communication. */
+
+#ifndef _OSPF_API_H
+#define _OSPF_API_H
+
+#define OSPF_API_VERSION           1
+
+/* MTYPE definition is not reflected to "memory.h". */
+#define MTYPE_OSPF_API_MSG      MTYPE_TMP
+#define MTYPE_OSPF_API_FIFO     MTYPE_TMP
+
+/* Default API server port to accept connection request from client-side. */
+/* This value could be overridden by "ospfapi" entry in "/etc/services". */
+#define OSPF_API_SYNC_PORT      2607
+
+/* -----------------------------------------------------------
+ * Generic messages 
+ * -----------------------------------------------------------
+ */
+
+/* Message header structure, fields are in network byte order and
+   aligned to four octets. */
+struct apimsghdr
+{
+  u_char version;		/* OSPF API protocol version */
+  u_char msgtype;		/* Type of message */
+  u_int16_t msglen;		/* Length of message w/o header */
+  u_int32_t msgseq;		/* Sequence number */
+};
+
+/* Message representation with header and body */
+struct msg
+{
+  struct msg *next;		/* to link into fifo */
+
+  /* Message header */
+  struct apimsghdr hdr;
+
+  /* Message body */
+  struct stream *s;
+};
+
+/* Prototypes for generic messages. */
+struct msg *msg_new (u_char msgtype, void *msgbody,
+		     u_int32_t seqnum, u_int16_t msglen);
+struct msg *msg_dup (struct msg *msg);
+void msg_print (struct msg *msg);	/* XXX debug only */
+void msg_free (struct msg *msg);
+struct msg *msg_read (int fd);
+int msg_write (int fd, struct msg *msg);
+
+/* For requests, the message sequence number is between MIN_SEQ and
+   MAX_SEQ. For notifications, the sequence number is 0. */
+
+#define MIN_SEQ          1
+#define MAX_SEQ 2147483647
+
+void msg_set_seq (struct msg *msg, u_int32_t seqnr);
+u_int32_t msg_get_seq (struct msg *msg);
+
+/* -----------------------------------------------------------
+ * Message fifo queues
+ * -----------------------------------------------------------
+ */
+
+/* Message queue structure. */
+struct msg_fifo
+{
+  unsigned long count;
+
+  struct msg *head;
+  struct msg *tail;
+};
+
+/* Prototype for message fifo queues. */
+struct msg_fifo *msg_fifo_new ();
+void msg_fifo_push (struct msg_fifo *, struct msg *msg);
+struct msg *msg_fifo_pop (struct msg_fifo *fifo);
+struct msg *msg_fifo_head (struct msg_fifo *fifo);
+void msg_fifo_flush (struct msg_fifo *fifo);
+void msg_fifo_free (struct msg_fifo *fifo);
+
+/* -----------------------------------------------------------
+ * Specific message type and format definitions
+ * -----------------------------------------------------------
+ */
+
+/* Messages to OSPF daemon. */
+#define MSG_REGISTER_OPAQUETYPE   1
+#define MSG_UNREGISTER_OPAQUETYPE 2
+#define MSG_REGISTER_EVENT        3
+#define MSG_SYNC_LSDB             4
+#define MSG_ORIGINATE_REQUEST     5
+#define MSG_DELETE_REQUEST        6
+
+/* Messages from OSPF daemon. */
+#define MSG_REPLY                10
+#define MSG_READY_NOTIFY         11
+#define MSG_LSA_UPDATE_NOTIFY    12
+#define MSG_LSA_DELETE_NOTIFY    13
+#define MSG_NEW_IF               14
+#define MSG_DEL_IF               15
+#define MSG_ISM_CHANGE           16
+#define MSG_NSM_CHANGE           17
+
+struct msg_register_opaque_type
+{
+  u_char lsatype;
+  u_char opaquetype;
+  u_char pad[2];		/* padding */
+};
+
+struct msg_unregister_opaque_type
+{
+  u_char lsatype;
+  u_char opaquetype;
+  u_char pad[2];		/* padding */
+};
+
+/* Power2 is needed to convert LSA types into bit positions,
+ * see typemask below. Type definition starts at 1, so
+ * Power2[0] is not used. */
+
+
+#ifdef ORIGINAL_CODING
+static const u_int16_t
+  Power2[] = { 0x0, 0x1, 0x2, 0x4, 0x8, 0x10, 0x20, 0x40, 0x80,
+  0x100, 0x200, 0x400, 0x800, 0x1000, 0x2000, 0x4000, 0x8000
+};
+#else
+static const u_int16_t
+  Power2[] = { 0, (1 << 0), (1 << 1), (1 << 2), (1 << 3), (1 << 4),
+  (1 << 5), (1 << 6), (1 << 7), (1 << 8), (1 << 9),
+  (1 << 10), (1 << 11), (1 << 12), (1 << 13), (1 << 14),
+  (1 << 15)
+};
+#endif /* ORIGINAL_CODING */
+
+struct lsa_filter_type
+{
+  u_int16_t typemask;		/* bitmask for selecting LSA types (1..16) */
+  u_char origin;		/* selects according to origin. */
+#define NON_SELF_ORIGINATED	0
+#define	SELF_ORIGINATED  (OSPF_LSA_SELF)
+#define	ANY_ORIGIN 2
+
+  u_char num_areas;		/* number of areas in the filter. */
+  /* areas, if any, go here. */
+};
+
+struct msg_register_event
+{
+  struct lsa_filter_type filter;
+};
+
+struct msg_sync_lsdb
+{
+  struct lsa_filter_type filter;
+};
+
+struct msg_originate_request
+{
+  /* Used for LSA type 9 otherwise ignored */
+  struct in_addr ifaddr;
+
+  /* Used for LSA type 10 otherwise ignored */
+  struct in_addr area_id;
+
+  /* LSA header and LSA-specific part */
+  struct lsa_header data;
+};
+
+struct msg_delete_request
+{
+  struct in_addr area_id;	/* "0.0.0.0" for AS-external opaque LSAs */
+  u_char lsa_type;
+  u_char opaque_type;
+  u_char pad[2];		/* padding */
+  u_int32_t opaque_id;
+};
+
+struct msg_reply
+{
+  char errcode;
+#define OSPF_API_OK                         0
+#define OSPF_API_NOSUCHINTERFACE          (-1)
+#define OSPF_API_NOSUCHAREA               (-2)
+#define OSPF_API_NOSUCHLSA                (-3)
+#define OSPF_API_ILLEGALLSATYPE           (-4)
+#define OSPF_API_OPAQUETYPEINUSE          (-5)
+#define OSPF_API_OPAQUETYPENOTREGISTERED  (-6)
+#define OSPF_API_NOTREADY                 (-7)
+#define OSPF_API_NOMEMORY                 (-8)
+#define OSPF_API_ERROR                    (-9)
+#define OSPF_API_UNDEF                   (-10)
+  u_char pad[3];		/* padding to four byte alignment */
+};
+
+/* Message to tell client application that it ospf daemon is 
+ * ready to accept opaque LSAs for a given interface or area. */
+
+struct msg_ready_notify
+{
+  u_char lsa_type;
+  u_char opaque_type;
+  u_char pad[2];		/* padding */
+  struct in_addr addr;		/* interface address or area address */
+};
+
+/* These messages have a dynamic length depending on the embodied LSA.
+   They are aligned to four octets. msg_lsa_change_notify is used for
+   both LSA update and LSAs delete. */
+
+struct msg_lsa_change_notify
+{
+  /* Used for LSA type 9 otherwise ignored */
+  struct in_addr ifaddr;
+  /* Area ID. Not valid for AS-External and Opaque11 LSAs. */
+  struct in_addr area_id;
+  u_char is_self_originated;	/* 1 if self originated. */
+  u_char pad[3];
+  struct lsa_header data;
+};
+
+struct msg_new_if
+{
+  struct in_addr ifaddr;	/* interface IP address */
+  struct in_addr area_id;	/* area this interface belongs to */
+};
+
+struct msg_del_if
+{
+  struct in_addr ifaddr;	/* interface IP address */
+};
+
+struct msg_ism_change
+{
+  struct in_addr ifaddr;	/* interface IP address */
+  struct in_addr area_id;	/* area this interface belongs to */
+  u_char status;		/* interface status (up/down) */
+  u_char pad[3];		/* not used */
+};
+
+struct msg_nsm_change
+{
+  struct in_addr ifaddr;	/* attached interface */
+  struct in_addr nbraddr;	/* Neighbor interface address */
+  struct in_addr router_id;	/* Router ID of neighbor */
+  u_char status;		/* NSM status */
+  u_char pad[3];
+};
+
+/* We make use of a union to define a structure that covers all
+   possible API messages. This allows us to find out how much memory
+   needs to be reserved for the largest API message. */
+struct apimsg
+{
+  struct apimsghdr hdr;
+  union
+  {
+    struct msg_register_opaque_type register_opaque_type;
+    struct msg_register_event register_event;
+    struct msg_sync_lsdb sync_lsdb;
+    struct msg_originate_request originate_request;
+    struct msg_delete_request delete_request;
+    struct msg_reply reply;
+    struct msg_ready_notify ready_notify;
+    struct msg_new_if new_if;
+    struct msg_del_if del_if;
+    struct msg_ism_change ism_change;
+    struct msg_nsm_change nsm_change;
+    struct msg_lsa_change_notify lsa_change_notify;
+  }
+  u;
+};
+
+#define OSPF_API_MAX_MSG_SIZE (sizeof(struct apimsg) + OSPF_MAX_LSA_SIZE)
+
+/* -----------------------------------------------------------
+ * Prototypes for specific messages
+ * -----------------------------------------------------------
+ */
+
+/* For debugging only. */
+void api_opaque_lsa_print (struct lsa_header *data);
+
+/* Messages sent by client */
+struct msg *new_msg_register_opaque_type (u_int32_t seqnum, u_char ltype,
+					  u_char otype);
+struct msg *new_msg_register_event (u_int32_t seqnum,
+				    struct lsa_filter_type *filter);
+struct msg *new_msg_sync_lsdb (u_int32_t seqnum,
+			       struct lsa_filter_type *filter);
+struct msg *new_msg_originate_request (u_int32_t seqnum,
+				       struct in_addr ifaddr,
+				       struct in_addr area_id,
+				       struct lsa_header *data);
+struct msg *new_msg_delete_request (u_int32_t seqnum,
+				    struct in_addr area_id,
+				    u_char lsa_type,
+				    u_char opaque_type, u_int32_t opaque_id);
+
+/* Messages sent by OSPF daemon */
+struct msg *new_msg_reply (u_int32_t seqnum, u_char rc);
+
+struct msg *new_msg_ready_notify (u_int32_t seqnr, u_char lsa_type,
+				  u_char opaque_type, struct in_addr addr);
+
+struct msg *new_msg_new_if (u_int32_t seqnr,
+			    struct in_addr ifaddr, struct in_addr area);
+
+struct msg *new_msg_del_if (u_int32_t seqnr, struct in_addr ifaddr);
+
+struct msg *new_msg_ism_change (u_int32_t seqnr, struct in_addr ifaddr,
+				struct in_addr area, u_char status);
+
+struct msg *new_msg_nsm_change (u_int32_t seqnr, struct in_addr ifaddr,
+				struct in_addr nbraddr,
+				struct in_addr router_id, u_char status);
+
+/* msgtype is MSG_LSA_UPDATE_NOTIFY or MSG_LSA_DELETE_NOTIFY */
+struct msg *new_msg_lsa_change_notify (u_char msgtype,
+				       u_int32_t seqnum,
+				       struct in_addr ifaddr,
+				       struct in_addr area_id,
+				       u_char is_self_originated,
+				       struct lsa_header *data);
+
+/* string printing functions */
+const char *ospf_api_errname (int errcode);
+const char *ospf_api_typename (int msgtype);
+
+#endif /* _OSPF_API_H */