netdev - Re: [RESEND PATCH 1/2] TCP: note received valid-cookie Fast Open option

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

Message-ID: <e50f6e80-61c8-4c6e-a7c2-9b3ab7b27d90@wizmail.org>
Date: Wed, 23 Apr 2025 12:46:27 +0100
From: Jeremy Harris <jgh@...mail.org>
To: Neal Cardwell <ncardwell@...gle.com>, Jeremy Harris <jgh@...m.org>
Cc: netdev@...r.kernel.org, edumazet@...gle.com
Subject: Re: [RESEND PATCH 1/2] TCP: note received valid-cookie Fast Open
 option

Thanks for the review.  I'm preparing a v2, and a patch to "ss" in iproute2.

> The "TCP:" prefix is not the typical prefix for Linux TCP changes. A
> "tcp:"  is much more common.
> 
> Please follow the convention that we try to adhere to for TCP TFO
> changes by using something like:
> 
>    tcp: fastopen: note received valid-cookie Fast Open option

Will change for v2.


>> -               syn_data_acked:1;/* data in SYN is acked by SYN-ACK */
>> +               syn_data_acked:1,/* data in SYN is acked by SYN-ACK */
>> +               syn_fastopen_in:1; /* Received SYN includes Fast Open option */
> 
> IMHO this field name and comment are slightly misleading.
> 
> Sometimes when a SYN is received with a TFO option the server will
> fail to create a child because the TFO cookie is incorrect.
> 
> When this bit is set, we know not only that the "Received SYN includes
> Fast Open option", but we also know that the TFO cookie was correct
> and a child socket was created.
> 
> So I would suggest a more specific comment and field name, like:
> 
>    syn_fastopen_child:1; /* created TFO passive child socket */

Done.

-- 
Cheers,
   Jeremy