tcp: refactor to consolidate TFO passive open code

Use a helper to consolidate two identical code block for passive TFO.

Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 25 insertions, 27 deletions

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 3a40584cb473..706a99ec73f6 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -5989,6 +5989,27 @@ reset_and_undo:
         return 1;
 }
 
+static void tcp_rcv_synrecv_state_fastopen(struct sock *sk)
+{
+        tcp_try_undo_loss(sk, false);
+        inet_csk(sk)->icsk_retransmits = 0;
+
+        /* Once we leave TCP_SYN_RECV or TCP_FIN_WAIT_1,
+         * we no longer need req so release it.
+         */
+        reqsk_fastopen_remove(sk, tcp_sk(sk)->fastopen_rsk, false);
+
+        /* Re-arm the timer because data may have been sent out.
+         * This is similar to the regular data transmission case
+         * when new data has just been ack'ed.
+         *
+         * (TFO) - we could try to be more aggressive and
+         * retransmitting any data sooner based on when they
+         * are sent out.
+         */
+        tcp_rearm_rto(sk);
+}
+
 /*
  *      This function implements the receiving procedure of RFC 793 for
  *      all states except ESTABLISHED and TIME_WAIT.
@@ -6085,22 +6106,8 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb)
                 if (!tp->srtt_us)
                         tcp_synack_rtt_meas(sk, req);
 
-                /* Once we leave TCP_SYN_RECV, we no longer need req
-                 * so release it.
-                 */
                 if (req) {
-                        tcp_try_undo_loss(sk, false);
-                        inet_csk(sk)->icsk_retransmits = 0;
-                        reqsk_fastopen_remove(sk, req, false);
-                        /* Re-arm the timer because data may have been sent out.
-                         * This is similar to the regular data transmission case
-                         * when new data has just been ack'ed.
-                         *
-                         * (TFO) - we could try to be more aggressive and
-                         * retransmitting any data sooner based on when they
-                         * are sent out.
-                         */
-                        tcp_rearm_rto(sk);
+                        tcp_rcv_synrecv_state_fastopen(sk);
                 } else {
                         tcp_try_undo_spurious_syn(sk);
                         tp->retrans_stamp = 0;
@@ -6138,18 +6145,9 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb)
         case TCP_FIN_WAIT1: {
                 int tmo;
 
-                /* If we enter the TCP_FIN_WAIT1 state and we are a
-                 * Fast Open socket and this is the first acceptable
-                 * ACK we have received, this would have acknowledged
-                 * our SYNACK so stop the SYNACK timer.
-                 */
-                if (req) {
-                        tcp_try_undo_loss(sk, false);
-                        inet_csk(sk)->icsk_retransmits = 0;
-                        /* We no longer need the request sock. */
-                        reqsk_fastopen_remove(sk, req, false);
-                        tcp_rearm_rto(sk);
-                }
+                if (req)
+                        tcp_rcv_synrecv_state_fastopen(sk);
+
                 if (tp->snd_una != tp->write_seq)
                         break;