tcp: socket option to set TCP fast open key

New socket option TCP_FASTOPEN_KEY to allow different keys per
listener.  The listener by default uses the global key until the
socket option is set.  The key is a 16 bytes long binary data. This
option has no effect on regular non-listener TCP sockets.

Signed-off-by: Yuchung Cheng <ycheng@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Christoph Paasch <cpaasch@apple.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 3b3b9b9..1efe836 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1555,9 +1555,10 @@ struct tcp_fastopen_request {
 	int				copied;	/* queued in tcp_connect() */
 };
 void tcp_free_fastopen_req(struct tcp_sock *tp);
-
+void tcp_fastopen_destroy_cipher(struct sock *sk);
 void tcp_fastopen_ctx_destroy(struct net *net);
-int tcp_fastopen_reset_cipher(struct net *net, void *key, unsigned int len);
+int tcp_fastopen_reset_cipher(struct net *net, struct sock *sk,
+			      void *key, unsigned int len);
 void tcp_fastopen_add_skb(struct sock *sk, struct sk_buff *skb);
 struct sock *tcp_try_fastopen(struct sock *sk, struct sk_buff *skb,
 			      struct request_sock *req,