[Bridge] Ethernet+Wireless Bridge?

Nicolas nicolas at no-spam.net
Fri May 2 05:04:27 PDT 2008


John W. Linville a écrit :
> 
> Spoofing the source MAC is actually forbidden by the 802.11 standard.

My two cents :

We all agree about the fact that most current wireless implementations 
do not permit spoofing the source MAC, probably for many good and 
several bad reasons.

But wouldn't it be possible, as a temporary and dirty fix, to simply 
send any outgoing frames with the wireless interface MAC as the source 
MAC when the bridge send on a wireless interface ?

Of course, this breaks the bridge transparency principle and might cause 
serious problem with BPDU, but on a simple (or simpler) configuration, 
without STP, this might work well for most level 3+ services. For 
example, an ARP answer can come for a different source MAC than the one 
stated in the ARP payload. So ARP should work well, even if the source 
MAC might look strange for someone having a close look at the frame.

Also, the bridge global MAC (of br0) might be forced to the MAC of the 
wireless interface if there is only a single wireless interface in the 
bridge, probably causing BPDU to work well too.

This is only theoretical and - I admit - a very dirty fix into the 
bridge code, but... better than noting. And by the way, may be this can 
be setup using ebtable, which is cleaner !

Any comments ?

	Nicolas.



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