tcp: fix Fast Open snmp over-counting bug

Fix incrementing TCPFastOpenActiveFailed snmp stats multiple times
when the handshake experiences multiple SYN timeouts.

Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c
index 448603a..193ba1f 100644 (file)
--- a/net/ipv4/tcp_timer.c
+++ b/net/ipv4/tcp_timer.c
@@ -168,7 +168,7 @@ static int tcp_write_timeout(struct sock *sk)
                        dst_negative_advice(sk);
                        if (tp->syn_fastopen || tp->syn_data)
                                tcp_fastopen_cache_set(sk, 0, NULL, true, 0);
-                       if (tp->syn_data)
+                       if (tp->syn_data && icsk->icsk_retransmits == 1)
                                NET_INC_STATS_BH(sock_net(sk),
                                                 LINUX_MIB_TCPFASTOPENACTIVEFAIL);
                }