]> git.baikalelectronics.ru Git - kernel.git/commit
tcp: fix TLP timer not set when CA_STATE changes from DISORDER to OPEN
authorPengcheng Yang <yangpc@wangsu.com>
Sun, 24 Jan 2021 05:07:14 +0000 (13:07 +0800)
committerJakub Kicinski <kuba@kernel.org>
Sun, 24 Jan 2021 05:33:01 +0000 (21:33 -0800)
commitaeb2c3028a921419d3634673d4f3042afef39701
treef64639d4b170ec4c65c48ee600d370b89a78308d
parent91a4048e0b127ba86417e7c45aab7b7c95bb571f
tcp: fix TLP timer not set when CA_STATE changes from DISORDER to OPEN

Upon receiving a cumulative ACK that changes the congestion state from
Disorder to Open, the TLP timer is not set. If the sender is app-limited,
it can only wait for the RTO timer to expire and retransmit.

The reason for this is that the TLP timer is set before the congestion
state changes in tcp_ack(), so we delay the time point of calling
tcp_set_xmit_timer() until after tcp_fastretrans_alert() returns and
remove the FLAG_SET_XMIT_TIMER from ack_flag when the RACK reorder timer
is set.

This commit has two additional benefits:
1) Make sure to reset RTO according to RFC6298 when receiving ACK, to
avoid spurious RTO caused by RTO timer early expires.
2) Reduce the xmit timer reschedule once per ACK when the RACK reorder
timer is set.

Fixes: 12676277cd2c ("tcp: fix xmit timer to only be reset if data ACKed/SACKed")
Link: https://lore.kernel.org/netdev/1611311242-6675-1-git-send-email-yangpc@wangsu.com
Signed-off-by: Pengcheng Yang <yangpc@wangsu.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/1611464834-23030-1-git-send-email-yangpc@wangsu.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
include/net/tcp.h
net/ipv4/tcp_input.c
net/ipv4/tcp_recovery.c