diff --git a/lib/sockunion.h b/lib/sockunion.h
new file mode 100644
index 0000000..99bdf6a
--- /dev/null
+++ b/lib/sockunion.h
@@ -0,0 +1,128 @@
+/*
+ * Socket union header.
+ * Copyright (c) 1997 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.  
+ */
+
+#ifndef _ZEBRA_SOCKUNION_H
+#define _ZEBRA_SOCKUNION_H
+
+#if 0
+union sockunion {
+  struct sockinet {
+    u_char si_len;
+    u_char si_family;
+    u_short si_port;
+  } su_si;
+  struct sockaddr_in  su_sin;
+  struct sockaddr_in6 su_sin6;
+};
+#define su_len                su_si.si_len
+#define su_family     su_si.si_family
+#define su_port               su_si.si_port
+#endif /* 0 */
+
+union sockunion 
+{
+  struct sockaddr sa;
+  struct sockaddr_in sin;
+#ifdef HAVE_IPV6
+  struct sockaddr_in6 sin6;
+#endif /* HAVE_IPV6 */
+};
+
+enum connect_result
+{
+  connect_error,
+  connect_success,
+  connect_in_progress
+};
+
+/* Default address family. */
+#ifdef HAVE_IPV6
+#define AF_INET_UNION AF_INET6
+#else
+#define AF_INET_UNION AF_INET
+#endif
+
+/* Sockunion address string length.  Same as INET6_ADDRSTRLEN. */
+#define SU_ADDRSTRLEN 46
+
+/* Macro to set link local index to the IPv6 address.  For KAME IPv6
+   stack. */
+#ifdef KAME
+#define	IN6_LINKLOCAL_IFINDEX(a)  ((a).s6_addr[2] << 8 | (a).s6_addr[3])
+#define SET_IN6_LINKLOCAL_IFINDEX(a, i) \
+  do { \
+    (a).s6_addr[2] = ((i) >> 8) & 0xff; \
+    (a).s6_addr[3] = (i) & 0xff; \
+  } while (0)
+#else
+#define	IN6_LINKLOCAL_IFINDEX(a)
+#define SET_IN6_LINKLOCAL_IFINDEX(a, i)
+#endif /* KAME */
+
+/* shortcut macro to specify address field of struct sockaddr */
+#define sock2ip(X)   (((struct sockaddr_in *)(X))->sin_addr.s_addr)
+#ifdef HAVE_IPV6
+#define sock2ip6(X)  (((struct sockaddr_in6 *)(X))->sin6_addr.s6_addr)
+#endif /* HAVE_IPV6 */
+
+#define sockunion_family(X)  (X)->sa.sa_family
+
+/* Prototypes. */
+int str2sockunion (char *, union sockunion *);
+const char *sockunion2str (union sockunion *, char *, size_t);
+int sockunion_cmp (union sockunion *, union sockunion *);
+int sockunion_same (union sockunion *, union sockunion *);
+
+char *sockunion_su2str (union sockunion *su);
+union sockunion *sockunion_str2su (char *str);
+struct in_addr sockunion_get_in_addr (union sockunion *su);
+int sockunion_accept (int sock, union sockunion *);
+int sockunion_stream_socket (union sockunion *);
+int sockopt_reuseaddr (int);
+int sockopt_reuseport (int);
+int sockunion_bind (int sock, union sockunion *, unsigned short, union sockunion *);
+int sockopt_ttl (int family, int sock, int ttl);
+int sockunion_socket (union sockunion *su);
+const char *inet_sutop (union sockunion *su, char *str);
+enum connect_result
+sockunion_connect (int fd, union sockunion *su, unsigned short port, unsigned int);
+union sockunion *sockunion_getsockname (int);
+union sockunion *sockunion_getpeername (int);
+union sockunion *sockunion_dup (union sockunion *);
+void sockunion_free (union sockunion *);
+
+#ifndef HAVE_INET_NTOP
+const char *
+inet_ntop (int family, const void *addrptr, char *strptr, size_t len);
+#endif /* HAVE_INET_NTOP */
+
+#ifndef HAVE_INET_PTON
+int
+inet_pton (int family, const char *strptr, void *addrptr);
+#endif /* HAVE_INET_PTON */
+
+#ifndef HAVE_INET_ATON
+int
+inet_aton (const char *cp, struct in_addr *inaddr);
+#endif
+
+#endif /* _ZEBRA_SOCKUNION_H */