[Tinyos-devel] BaseStationP bug

Chieh-Jan (Mike) Liang cliang4 at cs.jhu.edu
Mon Feb 18 16:27:47 PST 2008


Hi David,

One question about your fix. Before the radio packet is injected to 
serial, you erase the header. If I am not mistaken, after you do this, you 
need to set the packet source address back. This is for the "transparent" 
bridging.

Thank you

Mike

On Fri, 15 Feb 2008, David Moss wrote:

> The BaseStation application moves received packets directly into the send
> branch of the serial or radio stacks without clearing the header.  Residual
> header information is left over from the opposite communication driver,
> which can cause send/receive problems elsewhere.
>
>
>
> The case I'm seeing here is a message is received through the serial stack,
> causing the message's header to be filled in like a serial header.  The
> message is moved directly into the radio stack without clearing the header.
> Some bytes of a radio packet header, like FCF, are not edited by the radio
> stack because they are assumed to contain pre-configured settings.  The FCF
> byte is therefore corrupted by the bytes left over from the serial stack.
> This causes a node receiving the packet with the corrupted FCF byte to
> filter out and drop the packet.
>
>
>
> The solution is for the BaseStation application to clear each message_t's
> header before injecting the message into the send branch of the opposite
> communication driver.  I have attached my version of BaseStationP, but I
> would recommend the owner(s) of this application take a look before
> committing the fixes back to tinyos-2.x/apps/BaseStation.
>
>
>
> -David
>
>
>
>


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