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| author | Neal Cardwell <ncardwell@google.com> | 2012-09-22 06:18:55 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2012-09-22 21:47:10 +0200 |
| commit | 016818d076871c4ee34db1e8d74dc17ac1de626a (patch) | |
| tree | 60d0f20afb0937f61b5fc4611e53a2ac411a0646 /net/ipv4/tcp_input.c | |
| parent | tcp: extract code to compute SYNACK RTT (diff) | |
| download | linux-016818d076871c4ee34db1e8d74dc17ac1de626a.tar.xz linux-016818d076871c4ee34db1e8d74dc17ac1de626a.zip | |
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.c | 1 |
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 |