On 9/18/25 6:21 PM, chia-yu.chang@nokia-bell-labs.com wrote:

From: Chia-Yu Chang <redacted>

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.

Signed-off-by: Chia-Yu Chang <redacted>

This looks like a fix for an incorrect behavior introduced by a previous
AccECN patch. If so, please add a suitable fixes tag. We accept such
tags even for net-next material, and it's better to explicitly call out
needed fixes.

Thanks,

Paolo