From: Marcel Holtmann <marcel@holtmann.org>
To: BlueZ Mailing List <bluez-devel@lists.sourceforge.net>
Cc: Moritz Gmelin <moritz.gmelin@avetana.de>
Subject: Re: [Bluez-devel] Zero length L2CAP packets
Date: Thu, 10 Feb 2005 15:04:48 +0100 [thread overview]
Message-ID: <1108044288.15974.45.camel@pegasus> (raw)
In-Reply-To: <200502101112.09602.harbaum@beecon.de>
Hi Till,
> while working on the avetana jsr82 implementation we discovered, that the bt
> spec as well as jsr82 allow to transmit zero length l2cap packets. IMHO the
> linux socket interface does not support zero length packets and a read
> returning zero indicates an end of file (in this case meaning that the
> connection has been closed).
>
> What happens if the other side actually sends a zero length packet? Is this
> dropped inside the kernel? Or will read return zero which i'll misinterpret
> as the eof marker? How can i distinguish between eof and a zero length
> packet?
actually I see no problem with zero length L2CAP packets. I modified the
l2test program to actually be able to send and receive them, but there
is no problem at all. This is a socket and not a file and so you might
use poll() or select() to detect the hangup of the connection and not
some weird zero length magic.
The kernel btw is dropping no packets. I see all of these zero packets
flying from one end to the other.
Regards
Marcel
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next prev parent reply other threads:[~2005-02-10 14:04 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-02-10 10:12 [Bluez-devel] Zero length L2CAP packets Till Harbaum
2005-02-10 14:04 ` Marcel Holtmann [this message]
[not found] ` <2def10fdd2a185bcddd4562929cd1417@avetana.de>
2005-02-22 0:17 ` Marcel Holtmann
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