AW: AccessPoint 5GHz DFS Channel Radar Detection Failure

[Stärk Nadja <Nadja Staerk wiedemann-group com>]

Hello, 

thanks for your answer. 

I'm creating the connection on band wifi band a using this command:
nmcli con add type wifi ifname wlan0 autoconnect yes ssid $(hostname) 802-11-wireless.mode ap 
802-11-wireless.band a 802-11-wireless.channel 100  ipv4.addresses 192.168.201.1/24 ipv4.method shared 
wifi-sec.key-mgmt wpa-psk wifi-sec.psk TEST12345
I had a few problems to bring up the access point first, but when I changed the 802-1x.auth-timeout to 90 
seconds (CAC time) and send the correct country code to wpa_supplicant over dbus the access point is coming 
up as it should. Everything is fine until I need to switch the channel because a radar event is detected by 
the driver.

To simulate the radar event I use a debug feature of the WLink8 driver. I use the debugfs and write the 
channel to a specific file:
echo 100 > /sys/kernel/debug/ieee80211/phy0/wlcore/wl18xx/radar_detection
for triggering  a radar event on channel 100. We used this in the past with hostapd and it worked really 
good. 

I'm not sure how I can tell wpa_supplicant to use wlan0 instead of p2p-dev-wlan0. I only create the nmcli 
connection and I think the network manager is then configuring wpa_supplicant over dbus.

Thanks 
Nadja

-----Ursprüngliche Nachricht-----
Von: Beniamino Galvani <bgalvani redhat com> 
Gesendet: Montag, 10. Mai 2021 08:59
An: Stärk Nadja <Nadja Staerk wiedemann-group com>
Cc: networkmanager-list gnome org
Betreff: Re: AccessPoint 5GHz DFS Channel Radar Detection Failure [ NICHT VERSCHLUESSELT ] [ 
SIGNATUR_UNPRUEFBAR ]

On Wed, May 05, 2021 at 09:16:44AM +0000, Stärk Nadja wrote:
> Hello,
>
> I'm working with NetworkManager v1.22.8 and face some issues with my 5 GHz access point.
>
> I need to create it on DFS channel 100 and when a radar event is detected the channel should be switched.
>
> Debug output of wpa_supplicant is enabled.
> If I send a radar event through the debugfs to channel 100 now, I can see that it was received by 
> wpa_supplicant:
>
> nl80211: Event message available
>
> nl80211: Drv Event 94 (NL80211_CMD_RADAR_DETECT) received for 
> p2p-dev-wlan0
>
> nl80211: DFS event on freq 5500 MHz, ht: 1, offset: 0, width: 1, cf1: 
> 5500MHz, cf2: 0MHz
>
> p2p-dev-wlan0: Event DFS_RADAR_DETECTED (42) received

Hi, the event is detected on p2p-dev-wlan0, which is a P2P interface; probably it should be on wlan0 instead. 
How do you simulate the event?

> But the channel is not switched.
>
>
> I made some debugging in wpa_supplicant (v2.9) and figured out that the function 
> wpas_ap_event_dfs_radar_detected in ap.c instantly returned because the wpa_s->ap_iface and the 
> wpa_s->ifmsh is empty.
>
>
>
> Is the NetworkManager able to handle a fully working 5 GHz access point? Do I just need to add some extra 
> configurations?

Yes, I think it should if you set property 'wifi.band' to 'a'.

Beniamino