Hi,
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?
Regards,
Till
--
Dr.-Ing. Till Harbaum Tel.: +49 721 4998963
BeeCon GmbH Fax: +49 721 4998962
Haid-und-Neu Strasse 7, 76131 Karlsruhe Mobil: +49 179 9087904
[email protected] http://www.beecon.de
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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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