diff --git a/include/net/tcp.h b/include/net/tcp.h
index ae9774b..11119e3 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -29,6 +29,7 @@
 #include <linux/skbuff.h>
 #include <linux/dmaengine.h>
 #include <linux/crypto.h>
+#include <linux/cryptohash.h>
 
 #include <net/inet_connection_sock.h>
 #include <net/inet_timewait_sock.h>
@@ -434,11 +435,17 @@
 extern void			tcp_unhash(struct sock *sk);
 
 /* From syncookies.c */
+extern __u32 syncookie_secret[2][16-3+SHA_DIGEST_WORDS];
 extern struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb, 
 				    struct ip_options *opt);
 extern __u32 cookie_v4_init_sequence(struct sock *sk, struct sk_buff *skb, 
 				     __u16 *mss);
 
+/* From net/ipv6/syncookies.c */
+extern struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb);
+extern __u32 cookie_v6_init_sequence(struct sock *sk, struct sk_buff *skb,
+				     __u16 *mss);
+
 /* tcp_output.c */
 
 extern void __tcp_push_pending_frames(struct sock *sk, unsigned int cur_mss,
@@ -1332,6 +1339,7 @@
 extern void tcp_proc_unregister(struct tcp_seq_afinfo *afinfo);
 
 extern struct request_sock_ops tcp_request_sock_ops;
+extern struct request_sock_ops tcp6_request_sock_ops;
 
 extern int tcp_v4_destroy_sock(struct sock *sk);