Re: [PATCH] tcp: keepalive fixes

Hi, Eric:

Just to clarify: the issues for tcp keepalive and TCP_USER_TIMEOUT are
separate isues, and the fixes would not conflict afaik.

Thanks.  -- Enke

On Tue, Jan 12, 2021 at 11:52:43PM +0100, Eric Dumazet wrote:

On Tue, Jan 12, 2021 at 11:48 PM Yuchung Cheng [off-list ref] wrote:

quoted

On Tue, Jan 12, 2021 at 2:31 PM Enke Chen [off-list ref] wrote:

quoted

From: Enke Chen <redacted>

In this patch two issues with TCP keepalives are fixed:

1) TCP keepalive does not timeout when there are data waiting to be
   delivered and then the connection got broken. The TCP keepalive
   timeout is not evaluated in that condition.

hi enke
Do you have an example to demonstrate this issue -- in theory when
there is data inflight, an RTO timer should be pending (which
considers user-timeout setting). based on the user-timeout description
(man tcp), the user timeout should abort the socket per the specified
time after data commences. some data would help to understand the
issue.

+1

A packetdrill test would be ideal.

Also, given that there is this ongoing issue with TCP_USER_TIMEOUT,
lets not mix things
or risk added work for backports to stable versions.