Linux Ethernet Bridging - Apr 2007 - [Bridge] Making a bridge work without source address spoofing

So, I agree, the curent wireless card I have been given does not allow source
address spoofing, but I still would like to use bridging. I wonder if anyone has
tried modifying the bridge code to encapsulate the actual packet in some way so
that the desired source address can be preserved?

I am thinking of something like duplicating the ETH header, adding it to the
beginning of the packet, so that there are 2 headers. I know that the wireless
card strips the header off, adding its own header, and so it would strip off the
extra one, leaving the original unchanged. Then, when the packet arrives, I
would add software to strip the wireless header off again, leaving me with the
original packet again!

I guess I am thinking that I could add this "extra" header processing
in the wireless driver. Do you think this might work?

John Saxer
ITT A/CD San Diego

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On Wed, 14 Jul 2004 12:38:18 -0500
"Saxer, John -ACDSD" <John.Saxer@itt.com> wrote:
> 
> So, I agree, the curent wireless card I have been given does not
> allow source address spoofing, but I still would like to use
> bridging. I wonder if anyone has tried modifying the bridge code to
> encapsulate the actual packet in some way so that the desired source
> address can be preserved?
> 
> I am thinking of something like duplicating the ETH header, adding it
> to the beginning of the packet, so that there are 2 headers. I know
> that the wireless card strips the header off, adding its own header,
> and so it would strip off the extra one, leaving the original
> unchanged. Then, when the packet arrives, I would add software to
> strip the wireless header off again, leaving me with the original
> packet again!
> 
It won't work the data is sequential.

You could hack up a  your custom wireless driver to custom bridge code.
At which point you might as well forget bridging and just do routing
or tunneling.
> I guess I am thinking that I could add this "extra" header
processing
> in the wireless driver. Do you think this might work?
> 
Why bother? The point of the bridge is to be transparent.  If you
don't want it to be transparent?