wpa_supplicant AP mode DFS radar detection

Stärk Nadja Nadja.Staerk at wiedemann-group.com
Wed Apr 28 13:05:56 BST 2021


is wpa_supplicant v2.9 able to establish a fully working access point on a 5 GHz channel using DFS?

I used this configuration to bring up the access point:
Starting wpa_supplicant with debug prints I can see after some time (CAC takes its time), that the access point was fully brought up and is working.

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

But the channel is not switched.

I found 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 wpa_supplicant able to handle this or do I need hostapd for this? Or do I just need to add some extra configurations?
Using DFS channels with hostapd runs out of the box, but this is not really an option for me because I my goal is to use NetworkManager together with wpa_supplicant later.

Any help is appreciated.

Many thanks

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