[TCP]: TCP_DEFER_ACCEPT updates - process as established

Change TCP_DEFER_ACCEPT implementation so that it transitions a
connection to ESTABLISHED after handshake is complete instead of
leaving it in SYN-RECV until some data arrvies. Place connection in
accept queue when first data packet arrives from slow path.

Benefits:
  - established connection is now reset if it never makes it
   to the accept queue

 - diagnostic state of established matches with the packet traces
   showing completed handshake

 - TCP_DEFER_ACCEPT timeouts are expressed in seconds and can now be
   enforced with reasonable accuracy instead of rounding up to next
   exponential back-off of syn-ack retry.

Signed-off-by: Patrick McManus <mcmanus@ducksong.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 7 insertions, 0 deletions

diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index 08027f1d7f31..d96d9b122304 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -239,6 +239,11 @@ static inline struct tcp_request_sock *tcp_rsk(const struct request_sock *req)
         return (struct tcp_request_sock *)req;
 }
 
+struct tcp_deferred_accept_info {
+        struct sock *listen_sk;
+        struct request_sock *request;
+};
+
 struct tcp_sock {
         /* inet_connection_sock has to be the first member of tcp_sock */
         struct inet_connection_sock     inet_conn;
@@ -374,6 +379,8 @@ struct tcp_sock {
         unsigned int            keepalive_intvl;  /* time interval between keep alive probes */
         int                     linger2;
 
+        struct tcp_deferred_accept_info defer_tcp_accept;
+
         unsigned long last_synq_overflow; 
 
         u32     tso_deferred;