diff options
| author | Neal Cardwell <ncardwell@google.com> | 2024-10-01 20:05:17 +0000 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2024-10-03 16:18:04 -0700 |
| commit | 27c80efcc20486c82698f05f00e288b44513c86b (patch) | |
| tree | c985d650a2f714f9b320250ab394ec3a29e6fbaf /net | |
| parent | b41b4cbd9655bcebcce941bef3601db8110335be (diff) | |
tcp: fix TFO SYN_RECV to not zero retrans_stamp with retransmits out
Fix tcp_rcv_synrecv_state_fastopen() to not zero retrans_stamp
if retransmits are outstanding.
tcp_fastopen_synack_timer() sets retrans_stamp, so typically we'll
need to zero retrans_stamp here to prevent spurious
retransmits_timed_out(). The logic to zero retrans_stamp is from this
2019 commit:
commit cd736d8b67fb ("tcp: fix retrans timestamp on passive Fast Open")
However, in the corner case where the ACK of our TFO SYNACK carried
some SACK blocks that caused us to enter TCP_CA_Recovery then that
non-zero retrans_stamp corresponds to the active fast recovery, and we
need to leave retrans_stamp with its current non-zero value, for
correct ETIMEDOUT and undo behavior.
Fixes: cd736d8b67fb ("tcp: fix retrans timestamp on passive Fast Open")
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20241001200517.2756803-4-ncardwell.sw@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv4/tcp_input.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 8e47907c76d5..2d844e1f867f 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -6684,10 +6684,17 @@ static void tcp_rcv_synrecv_state_fastopen(struct sock *sk) if (inet_csk(sk)->icsk_ca_state == TCP_CA_Loss && !tp->packets_out) tcp_try_undo_recovery(sk); - /* Reset rtx states to prevent spurious retransmits_timed_out() */ tcp_update_rto_time(tp); - tp->retrans_stamp = 0; inet_csk(sk)->icsk_retransmits = 0; + /* In tcp_fastopen_synack_timer() on the first SYNACK RTO we set + * retrans_stamp but don't enter CA_Loss, so in case that happened we + * need to zero retrans_stamp here to prevent spurious + * retransmits_timed_out(). However, if the ACK of our SYNACK caused us + * to enter CA_Recovery then we need to leave retrans_stamp as it was + * set entering CA_Recovery, for correct retransmits_timed_out() and + * undo behavior. + */ + tcp_retrans_stamp_cleanup(sk); /* Once we leave TCP_SYN_RECV or TCP_FIN_WAIT_1, * we no longer need req so release it. |