Description of problem:
Customer has an application that receives a connection and keeps
receiving data without sending anything back, just pure ACKs. After
some time receiving periodic data from the client, the server starts
to send keepalive packets.
The upstream commit fixes this problem:
Date: Mon, 26 Apr 2010 18:33:27 +0000 (+0000)
Subject: TCP: avoid to send keepalive probes if receiving data
TCP: avoid to send keepalive probes if receiving data
RFC 1122 says the following:
Keep-alive packets MUST only be sent when no data or
acknowledgement packets have been received for the
connection within an interval.
The acknowledgement packet is reseting the keepalive
timer but the data packet isn't. This patch fixes it by
checking the timestamp of the last received data packet
too when the keepalive timer expires.
Signed-off-by: Flavio Leitner <firstname.lastname@example.org>
Signed-off-by: Eric Dumazet <email@example.com>
Acked-by: Ilpo Järvinen <firstname.lastname@example.org>
Signed-off-by: David S. Miller <email@example.com>
Version-Release number of selected component (if applicable):
all - including upstream before the commit above
Steps to Reproduce:
1. Run the server script on one system
2. Run the client script on another system
3. Watch the traffic dump and the time, even after the server had received
data packet, it will send a keepalive packet.
No keepalive sent as the data exchanged proves the connection is alive.
Brew build url with the upstream patch backported and applied:
Created attachment 414625 [details]
This request was evaluated by Red Hat Product Management for inclusion in a Red
Hat Enterprise Linux maintenance release. Product Management has requested
further review of this request by Red Hat Engineering, for potential
inclusion in a Red Hat Enterprise Linux Update release for currently deployed
products. This request is not yet committed for inclusion in an Update
You can download this test kernel from http://people.redhat.com/jwilson/el5
Detailed testing feedback is always welcomed.
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.