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authorNeal Cardwell <ncardwell@google.com>2012-09-22 08:18:55 +0400
committerDavid S. Miller <davem@davemloft.net>2012-09-22 23:47:10 +0400
commit016818d076871c4ee34db1e8d74dc17ac1de626a (patch)
tree60d0f20afb0937f61b5fc4611e53a2ac411a0646 /net/ipv4/tcp_input.c
parent623df484a777f3c00c1ea3d6a7565b8d8ac688a1 (diff)
downloadlinux-016818d076871c4ee34db1e8d74dc17ac1de626a.tar.xz
tcp: TCP Fast Open Server - take SYNACK RTT after completing 3WHS
When taking SYNACK RTT samples for servers using TCP Fast Open, fix the code to ensure that we only call tcp_valid_rtt_meas() after we receive the ACK that completes the 3-way handshake. Previously we were always taking an RTT sample in tcp_v4_syn_recv_sock(). However, for TCP Fast Open connections tcp_v4_conn_req_fastopen() calls tcp_v4_syn_recv_sock() at the time we receive the SYN. So for TFO we must wait until tcp_rcv_state_process() to take the RTT sample. To fix this, we wait until after TFO calls tcp_v4_syn_recv_sock() before we set the snt_synack timestamp, since tcp_synack_rtt_meas() already ensures that we only take a SYNACK RTT sample if snt_synack is non-zero. To be careful, we only take a snt_synack timestamp when a SYNACK transmit or retransmit succeeds. Signed-off-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_input.c')
-rw-r--r--net/ipv4/tcp_input.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index e2bec815ff23..bb326684495b 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -5983,6 +5983,7 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
* need req so release it.
*/
if (req) {
+ tcp_synack_rtt_meas(sk, req);
reqsk_fastopen_remove(sk, req, false);
} else {
/* Make sure socket is routed, for