netdev - TCP_DELACK_MIN vs TCP_ATO

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>] [day] [month] [year] [list]

Message-ID: <CAEnQRZAObcdhikY6GzG3mC1KZjgK8Xp5LzNetczmZP=BRPqN6w@mail.gmail.com>
Date:	Wed, 21 Sep 2011 15:59:54 +0300
From:	Daniel Baluta <daniel.baluta@...il.com>
To:	netdev@...r.kernel.org,
	kernelnewbies <kernelnewbies@...nelnewbies.org>
Subject: TCP_DELACK_MIN vs TCP_ATO_MIN

Hello,

RFC2582, Section 4.2 says:

"... an ACK SHOULD be generated for at least every second
full-sized segment, and MUST be generated within 500 ms
of the arrival of the first unacknowledged packet. ".

I guess that the delayed ACK timeout is computed in tcp_send_delayed_ack:

===
void tcp_send_delayed_ack(struct sock *sk)
{
        struct inet_connection_sock *icsk = inet_csk(sk);
        int ato = icsk->icsk_ack.ato;
        unsigned long timeout;

       /* .... */
        /* Stay within the limit we were given */
        timeout = jiffies + ato;
====

Can one explain what is the difference between TCP_DELACK_MIN and
TCP_ATO_MIN, specifically if the timeout (ato) is always in the interval
[TCP_DELACK_MIN, TCP_DELACK_MAX] ?

I want to make the delayed ack timeout configurable as some guys tried
here [1],
so for this reason I plan to make TCP_DELACK_MIN and TCP_DELACK_MAX
tunable via proc entries.

thanks,
Daniel.

[1] http://kerneltrap.org/mailarchive/linux-netdev/2008/9/9/3245554
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html