netdev - Re: [net PATCH 0/2] tcp: Address issues with ECT0 not being set in DCTCP packets

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:   Fri, 20 Nov 2020 18:22:19 -0800
From:   Jakub Kicinski <kuba@...nel.org>
To:     Alexander Duyck <alexander.duyck@...il.com>
Cc:     netdev@...r.kernel.org, bpf@...r.kernel.org, daniel@...earbox.net,
        kafai@...com, kernel-team@...com, edumazet@...gle.com,
        brakmo@...com, alexanderduyck@...com, weiwan@...gle.com
Subject: Re: [net PATCH 0/2] tcp: Address issues with ECT0 not being set in
 DCTCP packets

On Thu, 19 Nov 2020 13:23:43 -0800 Alexander Duyck wrote:
> This patch set is meant to address issues seen with SYN/ACK packets not
> containing the ECT0 bit when DCTCP is configured as the congestion control
> algorithm for a TCP socket.
> 
> A simple test using "tcpdump" and "test_progs -t bpf_tcp_ca" makes the
> issue obvious. Looking at the packets will result in the SYN/ACK packet
> with an ECT0 bit that does not match the other packets for the flow when
> the congestion control agorithm is switch from the default. So for example
> going from non-DCTCP to a DCTCP congestion control algorithm we will see
> the SYN/ACK IPV6 header will not have ECT0 set while the other packets in
> the flow will. Likewise if we switch from a default of DCTCP to cubic we
> will see the ECT0 bit set in the SYN/ACK while the other packets in the
> flow will not.

Applied, thanks!