redonkable/remarkable-linux
redonkable/remarkable-linux
1
0
Fork 0
Code Releases Activity

tcp: TCP Fast Open Server - record retransmits after 3WHS

Browse source 
When recording the number of SYNACK retransmits for servers using TCP
Fast Open, fix the code to ensure that we copy over the retransmit
count from the request_sock after we receive the ACK that completes
the 3-way handshake.

The story here is similar to that of SYNACK RTT
measurements. Previously we were always doing this 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 copy the final SYNACK retransmit
count in tcp_rcv_state_process().

Note that copying over the SYNACK retransmit count will give us the
correct count since, as is mentioned in a comment in
tcp_retransmit_timer(), before we receive an ACK for our SYN-ACK a TFO
passive connection does not retransmit anything else (e.g., data or
FIN segments).

Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Neal Cardwell 2012-09-22 17:03:47 +00:00 committed by David S. Miller
parent 5894bab7f4
commit 30099b2e9b
1 changed files with 2 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
net/ipv4/tcp_input.c
View file

@ -5985,6 +5985,8 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
*/
if (req) {
tcp_synack_rtt_meas(sk, req);
tp->total_retrans = req->retrans;
reqsk_fastopen_remove(sk, req, false);
} else {
/* Make sure socket is routed, for