netdev - Re: [net-next] tcp: add TCP_INFO status for failed client TFO

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Message-ID: <b781b46f-2682-6f59-1f61-312135b0924c@gmail.com>
Date:   Mon, 21 Oct 2019 12:02:07 -0700
From:   Eric Dumazet <eric.dumazet@...il.com>
To:     William Dauchy <wdauchy@...il.com>, Jason Baron <jbaron@...mai.com>
Cc:     "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        NETDEV <netdev@...r.kernel.org>,
        Neal Cardwell <ncardwell@...gle.com>,
        Christoph Paasch <cpaasch@...le.com>
Subject: Re: [net-next] tcp: add TCP_INFO status for failed client TFO

On 10/21/19 11:49 AM, William Dauchy wrote:

> I'm curious what would be the arguments compared to creating a new
> getsockopt() to fetch this data?

Reporting tsval/tsecr values were not well defined and seemed quite experimental to me.

TCP fastopen would use 2 unused bits, not real extra cost here.

This is persistent information after the connect(), while your tsval/tsecr report
seems quite dynamic stuff can be stale as soon as the info is fetched from the kernel.