On Wed, 2020-03-04 at 10:30 +0100, Markus Theil wrote: > > I used this patchset for some time to build a combined monitoring and > channel survey tool. > A mt76 based USB dongle is used, because mt76 supports the channel > survey cmd which yields the channel's busy time. > At the same time, the tool listens for beacons over the monitor > interface to log available networks and their RSSI to the user. > When the user changes into heatmap mode, he can issue active scan > requests at different points on the floor plan. All of this this > can be done with a single interface in monitor mode. I change the > frequency of the monitoring interface periodically to passively listen > at other channels. > > nl80211 is able to receive scan results in my setup. "iw dev $MON_IF > scan" also works as expected. > > A combination of an unassociated STA VIF and a monitor VIF (scan on STA > VIF, receive Wi-Fi frames on monitor VIF) does not work, because > I cannot freely set the channel on an unassociated STA VIF. Trying to > set the operating frequency on the monitor VIF also fails, when the STA > VIF is up. > Bringing the STA VIF up would be needed for scanning on it. > > Therefore this patches solved my solely monitoring-oriented use-case. Yeah, I kinda see where you're coming from, but I still don't think this makes a lot of sense. I'm actually surprised that "iw dev mon scan" works (in that it prints results) - would have expected the results to just go nowhere? And as you say, you're actually sending probe requests here, while you cannot even set the MAC address properly on a radiotap monitor interface. I don't really think we should mix all these concepts, the more things we try to allow in monitor mode, the more confusing that becomes (is it active now? or passive?) johannes
