From: Josh Horvath <Josh_Horvath-AJH051@email.mot.com>
To: David Ashley <dash@xdr.com>
Cc: linuxppc-embedded@lists.linuxppc.org
Subject: Re: BUG: udp socket, getsockopt + setsockopt
Date: Tue, 29 Jan 2002 10:58:59 -0600 [thread overview]
Message-ID: <3C56D4D3.CC3E7D03@motorola.com> (raw)
In-Reply-To: 200201291649.g0TGn2x09346@xdr.com
This is just a guess, but is SO_RCVLOWAT getting set somewhere? The receive
call will block until it gets the number of bytes set with this option. I
think it defaults to 1, so it should normally return when any data is
available on the socket. But if it has been bumped up to a big number, it
might account for the behavior you're seeing.
-Josh
David Ashley wrote:
>
> I've found a very strange bug in linux ppc 2.4.17, I think. I'm pulling
> udp packets off the LAN and reading them in a user space program. They come
> in sets of about 60k bytes all together, then pause for a while. I only can
> read the first 48k successfully, then they get lost.
>
> If I have a setsockopt call on the socket, setting SO_RCVBUF to 65535,
> then I don't lose any data. But if I do a getsockopt beforehand on
> SO_RCVBUF, it reports 65535. Without the setsockopt I get the packet loss,
> with it I don't lose any. It is strange because the value doesn't appear
> to be changing.
>
> What can be causing this mysterious behaviour?
>
> -Dave
>
** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
next prev parent reply other threads:[~2002-01-29 16:58 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-01-29 16:49 BUG: udp socket, getsockopt + setsockopt David Ashley
2002-01-29 16:58 ` Josh Horvath [this message]
2002-01-30 0:05 ` Val Henson
-- strict thread matches above, loose matches on Subject: below --
2002-01-30 3:22 David Ashley
2002-01-30 3:26 David Ashley
2002-01-30 3:41 ` Val Henson
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