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author | Damian Lukowski <damian@tvk.rwth-aachen.de> | 2009-12-07 06:06:15 +0000 |
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committer | David S. Miller <davem@davemloft.net> | 2009-12-08 20:56:11 -0800 |
commit | 07f29bc5bbae4e53e982ab956fed7207990a7786 (patch) | |
tree | b44506c37ce4886220439b38ef647c3cd7fbc6ce /net | |
parent | cb19054697e92a793f336380fd72c588521178ff (diff) | |
download | linux-3.10-07f29bc5bbae4e53e982ab956fed7207990a7786.tar.gz linux-3.10-07f29bc5bbae4e53e982ab956fed7207990a7786.tar.bz2 linux-3.10-07f29bc5bbae4e53e982ab956fed7207990a7786.zip |
tcp: Stalling connections: Fix timeout calculation routine
This patch fixes a problem in the TCP connection timeout calculation.
Currently, timeout decisions are made on the basis of the current
tcp_time_stamp and retrans_stamp, which is usually set at the first
retransmission.
However, if the retransmission fails in tcp_retransmit_skb(),
retrans_stamp is not updated and remains zero. This leads to wrong
decisions in retransmits_timed_out() if tcp_time_stamp is larger than
the specified timeout, which is very likely.
In this case, the TCP connection dies after the first attempted
(and unsuccessful) retransmission.
With this patch, tcp_skb_cb->when is used instead, when retrans_stamp
is not available.
This bug has been introduced together with retransmits_timed_out() in
2.6.32, as the number of retransmissions has been used for timeout
decisions before. The corresponding commit was
6fa12c85031485dff38ce550c24f10da23b0adaa (Revert Backoff [v3]:
Calculate TCP's connection close threshold as a time value.).
Thanks to Ilpo Järvinen for code suggestions and Frederic Leroy for
testing.
Reported-by: Frederic Leroy <fredo@starox.org>
Signed-off-by: Damian Lukowski <damian@tvk.rwth-aachen.de>
Acked-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
0 files changed, 0 insertions, 0 deletions