]> git.proxmox.com Git - mirror_ubuntu-eoan-kernel.git/commit
tcp: fix cwnd undo on DSACK in F-RTO
authorYuchung Cheng <ycheng@google.com>
Fri, 30 May 2014 22:25:59 +0000 (15:25 -0700)
committerDavid S. Miller <davem@davemloft.net>
Mon, 2 Jun 2014 23:50:49 +0000 (16:50 -0700)
commit0cfa5c07d6d1d7f8e710fc671c5ba1ce85e09fa4
treea64c77549f5863019d69eb08d25b557ba6a6f5b1
parent2d7a85f4b06e9c27ff629f07a524c48074f07f81
tcp: fix cwnd undo on DSACK in F-RTO

This bug is discovered by an recent F-RTO issue on tcpm list
https://www.ietf.org/mail-archive/web/tcpm/current/msg08794.html

The bug is that currently F-RTO does not use DSACK to undo cwnd in
certain cases: upon receiving an ACK after the RTO retransmission in
F-RTO, and the ACK has DSACK indicating the retransmission is spurious,
the sender only calls tcp_try_undo_loss() if some never retransmisted
data is sacked (FLAG_ORIG_DATA_SACKED).

The correct behavior is to unconditionally call tcp_try_undo_loss so
the DSACK information is used properly to undo the cwnd reduction.

Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/ipv4/tcp_input.c