netdev - Re: Whence a description of how to enable TCP FASTOPEN in a net-next kernel?

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: <1355781834.9380.13.camel@edumazet-glaptop>
Date:	Mon, 17 Dec 2012 14:03:54 -0800
From:	Eric Dumazet <erdnetdev@...il.com>
To:	Rick Jones <rick.jones2@...com>
Cc:	netdev@...r.kernel.org
Subject: Re: Whence a description of how to enable TCP FASTOPEN in a
 net-next kernel?

On Mon, 2012-12-17 at 13:56 -0800, Eric Dumazet wrote:

> 
> I guess you need to enable fastopen both for client and server :
> 
> echo 3 >/proc/sys//net/ipv4/tcp_fastopen

vi +475 Documentation/networking/ip-sysctl.txt

tcp_fastopen - INTEGER
        Enable TCP Fast Open feature (draft-ietf-tcpm-fastopen) to send data
        in the opening SYN packet. To use this feature, the client application
        must use sendmsg() or sendto() with MSG_FASTOPEN flag rather than
        connect() to perform a TCP handshake automatically.

        The values (bitmap) are
        1: Enables sending data in the opening SYN on the client.
        2: Enables TCP Fast Open on the server side, i.e., allowing data in
           a SYN packet to be accepted and passed to the application before
           3-way hand shake finishes.
        4: Send data in the opening SYN regardless of cookie availability and
           without a cookie option.
        0x100: Accept SYN data w/o validating the cookie.
        0x200: Accept data-in-SYN w/o any cookie option present.
        0x400/0x800: Enable Fast Open on all listeners regardless of the
           TCP_FASTOPEN socket option. The two different flags designate two
           different ways of setting max_qlen without the TCP_FASTOPEN socket
           option.

        Default: 0

        Note that the client & server side Fast Open flags (1 and 2
        respectively) must be also enabled before the rest of flags can take
        effect.

        See include/net/tcp.h and the code for more details.



--
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