RE: [PATCH v9 net-next 13/15] tcp: accecn: add tcpi_ecn_mode and tcpi_option2 in tcp_info

-----Original Message-----
From: Chia-Yu Chang (Nokia) 
Sent: Tuesday, January 20, 2026 12:38 PM
To: 'Eric Dumazet' <edumazet@google.com>
Cc: pabeni@redhat.com; parav@nvidia.com; linux-doc@vger.kernel.org; corbet@lwn.net; horms@kernel.org; dsahern@kernel.org; kuniyu@google.com; bpf@vger.kernel.org; netdev@vger.kernel.org; dave.taht@gmail.com; jhs@mojatatu.com; kuba@kernel.org; stephen@networkplumber.org; xiyou.wangcong@gmail.com; jiri@resnulli.us; davem@davemloft.net; andrew+netdev@lunn.ch; donald.hunter@gmail.com; ast@fiberby.net; liuhangbin@gmail.com; shuah@kernel.org; linux-kselftest@vger.kernel.org; ij@kernel.org; ncardwell@google.com; Koen De Schepper (Nokia) <redacted>; g.white@cablelabs.com; ingemar.s.johansson@ericsson.com; mirja.kuehlewind@ericsson.com; cheshire <redacted>; rs.ietf@gmx.at; Jason_Livingood@comcast.com; Vidhi Goel <redacted>
Subject: RE: [PATCH v9 net-next 13/15] tcp: accecn: add tcpi_ecn_mode and tcpi_option2 in tcp_info

quoted

-----Original Message-----
From: Eric Dumazet <edumazet@google.com>
Sent: Tuesday, January 20, 2026 12:18 PM
To: Chia-Yu Chang (Nokia) <redacted>
Cc: pabeni@redhat.com; parav@nvidia.com; linux-doc@vger.kernel.org; 
corbet@lwn.net; horms@kernel.org; dsahern@kernel.org; 
kuniyu@google.com; bpf@vger.kernel.org; netdev@vger.kernel.org; 
dave.taht@gmail.com; jhs@mojatatu.com; kuba@kernel.org; 
stephen@networkplumber.org; xiyou.wangcong@gmail.com; 
jiri@resnulli.us; davem@davemloft.net; andrew+netdev@lunn.ch; 
donald.hunter@gmail.com; ast@fiberby.net; liuhangbin@gmail.com; 
shuah@kernel.org; linux-kselftest@vger.kernel.org; ij@kernel.org; 
ncardwell@google.com; Koen De Schepper (Nokia) 
[off-list ref]; g.white@cablelabs.com; 
ingemar.s.johansson@ericsson.com; mirja.kuehlewind@ericsson.com; 
cheshire [off-list ref]; rs.ietf@gmx.at; 
Jason_Livingood@comcast.com; Vidhi Goel [off-list ref]
Subject: Re: [PATCH v9 net-next 13/15] tcp: accecn: add tcpi_ecn_mode 
and tcpi_option2 in tcp_info


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On Mon, Jan 19, 2026 at 7:59 PM [off-list ref] wrote:

quoted

From: Chia-Yu Chang <redacted>

Add 2-bit tcpi_ecn_mode feild within tcp_info to indicate which ECN 
mode is negotiated: ECN_MODE_DISABLED, ECN_MODE_RFC3168, 
ECN_MODE_ACCECN, or ECN_MODE_PENDING. This is done by utilizing 
available bits from tcpi_accecn_opt_seen (reduced from 16 bits to 2
bits) and tcpi_accecn_fail_mode (reduced from 16 bits to 4 bits).

Also, an extra 24-bit tcpi_options2 field is identified to represent 
newer options and connection features, as all 8 bits of tcpi_options 
field have been used.

Signed-off-by: Chia-Yu Chang <redacted>
Co-developed-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>

Are you sure Neal Cardwell really is ok with this patch, saw it and gave his SOB ?

This was discussed in another thread with Neal: "[PATCH net-next 1/1] selftests/net: Add packetdrill packetdrill cases". And Neal/me discussed this change.
But it was my miss that not syncing live update of tcp_info in packetdrill.
So, I will fix in the next net-next, thanks.

Chia-Yu