linux/include
Damian Lukowski 07f29bc5bb 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
6fa12c8503 (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>
2009-12-08 20:56:11 -08:00
..
acpi
asm-generic Merge branch 'for-2.6.33' of git://git.kernel.dk/linux-2.6-block 2009-12-08 08:19:16 -08:00
crypto
drm
keys
linux include/linux/if_ether.h: Remove unused defines MAC_BUF_SIZE and DECLARE_MAC_BUF 2009-12-08 20:42:28 -08:00
math-emu
media
mtd
net tcp: Stalling connections: Fix timeout calculation routine 2009-12-08 20:56:11 -08:00
pcmcia Merge git://git.kernel.org/pub/scm/linux/kernel/git/brodo/pcmcia-2.6 2009-12-05 09:42:59 -08:00
rdma
rxrpc
scsi [SCSI] fix async scan add/remove race resulting in an oops 2009-11-26 09:43:39 -06:00
sound Merge branch 'topic/hda' into for-linus 2009-12-04 16:22:45 +01:00
trace Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-12-05 15:30:21 -08:00
video pxa168fb: remove useless vsync/hsync invert flag 2009-12-01 09:02:32 +08:00
xen
Kbuild