netdev - Re: SO_LINGER dead: I get an immediate RST on 2.6.24?

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Message-ID: <175f5a0f0901111408s7905e5d9l2155b841f1ac054d@mail.gmail.com>
Date:	Sun, 11 Jan 2009 23:08:16 +0100
From:	"H. Willstrand" <h.willstrand@...il.com>
To:	bert hubert <bert.hubert@...herlabs.nl>, netdev@...r.kernel.org
Subject: Re: SO_LINGER dead: I get an immediate RST on 2.6.24?

On Sun, Jan 11, 2009 at 10:23 PM, bert hubert <bert.hubert@...herlabs.nl> wrote:
> Hi everybody,
>
> I have an application where I need to send data from A to B, and beforehand,
> I don't know how much data this will be.
>
> B is 'stupid', and consists solely of a TCP/IP port accepting data, and I
> have no way to chunk this data. So what I do is issue blocking calls to
> write(), shutdown(fd, SHUT_WR), and wait for the fd to become readable which
> tells me that the remote has packed up, and I'm good to go.
>
> Before this, I've tried SO_LINGER with various timeouts but nothing helped.
>
> When I tcpdump, I find that my close() is immediately turned into an RST
> packet.
>
> Is SO_LINGER a NOOP? Does it still do anything?
>
> I'm about to blog this up - the 'shutdown() and read()' technique is
> something I had to purloin from the Apache source.
>
> So I'd love to know the words of the wise on this one.
>
> Thanks.
>
> --
> http://www.PowerDNS.com      Open source, database driven DNS Software
> http://netherlabs.nl              Open and Closed source services
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>

This is the correct behavior according to RFC 2525, see section 2.17
(there are an example).

//H.W.
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