I have an AP and 2 stations. The wifi interfaces on the stations are in
bridges. Pinging from one station to the other generates this error.
This does not occur if the station interfaces are not in a bridge.
The bridge puts the station wifi interface in promiscuous mode. After
instrumenting the bridge code, the following seems to be happening. In
the case of a frame sent from S1->AP->S2, S1 also receives the AP->S2
frame. When that frame is converted to 802.3, S1 is the source address
and the bridge code complains.
I don't understand why the station interface needs to be in promiscuous
mode. The 4addr frames would seem to make this unnecessary.
As a test, I ignored promiscuous mode for stations in the ath9k driver
(a hack) and the messages disappeared. The setup then functions as a
client bridge in that computers hooked to one station can ping computers
connected to the other station.
I think this is a bug.
Steve