Re: [PATCH net-next v3] tcp: enable mid stream window clamp

On Thu, Aug 26, 2021 at 12:11 PM Yuchung Cheng [off-list ref] wrote:

On Wed, Aug 25, 2021 at 2:02 PM Neil Spring [off-list ref] wrote:

quoted

The TCP_WINDOW_CLAMP socket option is defined in tcp(7) to "Bound the size
of the advertised window to this value."  Window clamping is distributed
across two variables, window_clamp ("Maximal window to advertise" in
tcp.h) and rcv_ssthresh ("Current window clamp").

This patch updates the function where the window clamp is set to also
reduce the current window clamp, rcv_sshthresh, if needed.  With this,
setting the TCP_WINDOW_CLAMP option has the documented effect of limiting
the window.

This patch looks like a bug-fix so it should be applied to net not net-next?

It seems TCP_WINDOW_CLAMP never worked in this context, not sure
if any application was expecting it to work.

Note that if we target net tree, we would like a Fixes: tag.

I will give my SOB a bit later in the day, I have to run some errands.

Thanks.