[TWSK]: Introduce struct timewait_sock_ops

So that we can share several timewait sockets related functions and
make the timewait mini sockets infrastructure closer to the request
mini sockets one.

Next changesets will take advantage of this, moving more code out of
TCP and DCCP v4 and v6 to common infrastructure.

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 83b117a..176221c 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -287,6 +287,9 @@
 
 extern void			tcp_rcv_space_adjust(struct sock *sk);
 
+extern int			tcp_twsk_unique(struct sock *sk,
+						struct sock *sktw, void *twp);
+
 static inline void tcp_dec_quickack_mode(struct sock *sk,
 					 const unsigned int pkts)
 {