Re: Remote access points not visible while local wifi configured as access point

[Dan Williams <dcbw redhat com>]

On Wed, 2016-12-14 at 21:28 +0000, Stéphane Boucher wrote:
> It looks like NetworkManager purposely filters out remote access
> points while the local device is used as an access point?
>
> “nmcli d wifi” only displays the local access point, even though “Iw
> dev wlan0 scan” does show remote access points.
>
> I have a use case where I need to switch WIFI from AP to
> Client.   But that does not seem possible with NetworkManager.
>
> Or is there a way to force NetworkManager to not filter out access
> points?

Asking a AP-mode WiFi interface to scan will disconnect any associated
clients because during the scan, the AP can't beacon.  The AP will also
lose any traffic the client sends to the AP while it's on other
channels.  A scan can sometimes be forced, but the only two mac80211
drivers in the 4.9 and earlier kernels that advertise this are the TI
WiLink ones (in some embedded devices the Nokia N900/N9/N950 phones)
and ath10k ones.  Of non-mac80211 drivers some "support" it (ath6kl,
brcmfmac, mwifiex) while others don't (wil6210, rndis). But you'll
still drop traffic for any connected clients.

NM could theoretically request/allow scans if it could figure out how
many connected clients there were while in AP mode.  That would be a
nice enhancement.

If you want to switch the device from AP to Client mode, you would
create two WiFi profiles (what NM calls "connections").  One for client
mode, one for AP mode.  You can then switch between them:

nmcli con up "My AP" --wait 20
nmcli con up "My Client" --wait 20
nmcli dev wifi list  (the switch to client will have already scanned)

Or, if all you care about is scanning, you can just disconnect:

nmcli con up "My AP" --wait 20
nmcli dev disconnect wlan0
nmcli dev wifi
rescan
nmcli dev wifi list
nmcli con up "My AP" --wait 20

Dan

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