[IPV6]: Introduce inet6_timewait_sock

Out of tcp6_timewait_sock, that now is just an aggregation of
inet_timewait_sock and inet6_timewait_sock, using tw_ipv6_offset in struct
inet_timewait_sock, that is common to the IPv6 transport protocols that use
timewait sockets, like DCCP and TCP.

tw_ipv6_offset plays the struct inet_sock pinfo6 role, i.e. for the generic
code to find the IPv6 area in a timewait sock.

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/inet6_hashtables.h b/include/net/inet6_hashtables.h
index a4a204f..25f708f 100644
--- a/include/net/inet6_hashtables.h
+++ b/include/net/inet6_hashtables.h
@@ -110,10 +110,10 @@
 
 		if(*((__u32 *)&(tw->tw_dport))	== ports	&&
 		   sk->sk_family		== PF_INET6) {
-			const struct tcp6_timewait_sock *tcp6tw = tcp6_twsk(sk);
+			const struct inet6_timewait_sock *tw6 = inet6_twsk(sk);
 
-			if (ipv6_addr_equal(&tcp6tw->tw_v6_daddr, saddr)	&&
-			    ipv6_addr_equal(&tcp6tw->tw_v6_rcv_saddr, daddr)	&&
+			if (ipv6_addr_equal(&tw6->tw_v6_daddr, saddr)	&&
+			    ipv6_addr_equal(&tw6->tw_v6_rcv_saddr, daddr)	&&
 			    (!sk->sk_bound_dev_if || sk->sk_bound_dev_if == dif))
 				goto hit;
 		}