diff options
| author |   Neal Cardwell <ncardwell@google.com> | 2012-09-22 04:18:55 +0000 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2012-09-22 15:47:10 -0400 |
| commit | 016818d076871c4ee34db1e8d74dc17ac1de626a (patch) | |
| tree | 60d0f20afb0937f61b5fc4611e53a2ac411a0646 /include/net | |
| parent | tcp: extract code to compute SYNACK RTT (diff) | |
| download | linux-dev-016818d076871c4ee34db1e8d74dc17ac1de626a.tar.xz linux-dev-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 'include/net')
| -rw-r--r-- | include/net/tcp.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/net/tcp.h b/include/net/tcp.h index a718d0e3d8e7..6feeccd83dd7 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -1125,6 +1125,7 @@ static inline void tcp_openreq_init(struct request_sock *req, req->cookie_ts = 0; tcp_rsk(req)->rcv_isn = TCP_SKB_CB(skb)->seq; tcp_rsk(req)->rcv_nxt = TCP_SKB_CB(skb)->seq + 1; + tcp_rsk(req)->snt_synack = 0; req->mss = rx_opt->mss_clamp; req->ts_recent = rx_opt->saw_tstamp ? rx_opt->rcv_tsval : 0; ireq->tstamp_ok = rx_opt->tstamp_ok; |