Re: [PATCH v4 net-next 05/13] tcp: accecn: handle unexpected AccECN negotiation feedback

[Paolo Abeni]

On 10/13/25 7:03 PM, chia-yu.ch...@nokia-bell-labs.com wrote:
> From: Chia-Yu Chang <chia-yu.ch...@nokia-bell-labs.com>
> 
> According to Section 3.1.2 of AccECN spec (RFC9768), if a TCP Client
> has sent a SYN requesting AccECN feedback with (AE,CWR,ECE) = (1,1,1)
> then receives a SYN/ACK with the currently reserved combination
> (AE,CWR,ECE) = (1,0,1) but it does not have logic specific to such a
> combination, the Client MUST enable AccECN mode as if the SYN/ACK
> confirmed that the Server supported AccECN and as if it fed back that
> the IP-ECN field on the SYN had arrived unchanged.
> 
> This patch fix an incorrect AccECN negoation of commit 3cae34274c79
> ("tcp: accecn: AccECN negotiation").

Minor nit: with my previous feedback I asked a formal fixes tag here.

Yes, we can have fixes tag on net-next.

No need to re-submit just for this.

/P