tcp: Fix a connect() race with timewait sockets

First patch changes __inet_hash_nolisten() and __inet6_hash()
to get a timewait parameter to be able to unhash it from ehash
at same time the new socket is inserted in hash.

This makes sure timewait socket wont be found by a concurrent
writer in __inet_check_established()

Reported-by: kapil dakhane <kdakhane@gmail.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/dccp/ipv6.c b/net/dccp/ipv6.c
index 6574215..baf05cf 100644
--- a/net/dccp/ipv6.c
+++ b/net/dccp/ipv6.c
@@ -46,7 +46,7 @@
 			return;
 		}
 		local_bh_disable();
-		__inet6_hash(sk);
+		__inet6_hash(sk, NULL);
 		local_bh_enable();
 	}
 }
@@ -644,7 +644,7 @@
 	newinet->inet_daddr = newinet->inet_saddr = LOOPBACK4_IPV6;
 	newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
 
-	__inet6_hash(newsk);
+	__inet6_hash(newsk, NULL);
 	__inet_inherit_port(sk, newsk);
 
 	return newsk;