channel not allowed for AP mode, RADAR

beroal · 09-14-2020, 01:53 AM

I have a USB Wi-Fi network card that I want to use as a Wi-Fi access point. When I configure the card to work on a channel in the radar band (namely, channels 52, 100, 116, 132), "hostapd" exits with the message

Code:

Channel 52 (primary) not allowed for AP mode, flags: 0x979 RADAR

The number after "flags" depends on the channel. AFAIK, even if there are radars working, the card should migrate to another channel instead of refusing to work. My AP works on non-radar channels. Changing channel width ("vht_oper_chwidth") does not lift this restriction. I wonder is this a limitation of the chip of the card, the driver or "hostapd"?

Code:

>cat /etc/hostapd/hostapd.conf
# Wireless Interface
driver=nl80211
interface=wifiap
logger_syslog=-1
logger_syslog_level=2
logger_stdout=-1
logger_stdout_level=2

# Wireless Environment
country_code=UA
country3=0x49
ieee80211d=1
ieee80211h=1
ieee80211n=1
ieee80211ac=1
hw_mode=a
require_ht=1
require_vht=1
ht_capab=[HT40+][SHORT-GI-20][SHORT-GI-40][DSSS_CCK-40][MAX-AMSDU-3839]
vht_capab=[MAX-MPDU-3895][SHORT-GI-80][SU-BEAMFORMEE]
vht_oper_chwidth=1
channel=52
vht_oper_centr_freq_seg0_idx=58
ssid=skipped

# Authentication and Encryption
macaddr_acl=0
auth_algs=1
ignore_broadcast_ssid=0
wpa=2
wpa_passphrase=skipped
wpa_key_mgmt=WPA-PSK
wpa_pairwise=TKIP CCMP
rsn_pairwise=CCMP

Code:

>hostapd -dd /etc/hostapd/hostapd.conf
random: Trying to read entropy from /dev/random
Configuration file: /etc/hostapd/hostapd.conf
nl80211: Supported cipher 00-0f-ac:1
nl80211: Supported cipher 00-0f-ac:5
nl80211: Supported cipher 00-0f-ac:2
nl80211: Supported cipher 00-0f-ac:4
nl80211: Supported cipher 00-0f-ac:6
nl80211: interface wifiap in phy phy0
nl80211: Set mode ifindex 3 iftype 3 (AP)
nl80211: Setup AP(wifiap) - device_ap_sme=1 use_monitor=0
nl80211: Subscribe to mgmt frames with AP handle 0x558a43d5b0e0 (device SME)
nl80211: Register frame type=0xd0 (WLAN_FC_STYPE_ACTION) nl_handle=0x558a43d5b0e0 match=04
nl80211: Register frame type=0xd0 (WLAN_FC_STYPE_ACTION) nl_handle=0x558a43d5b0e0 match=0501
nl80211: Register frame type=0xd0 (WLAN_FC_STYPE_ACTION) nl_handle=0x558a43d5b0e0 match=0503
nl80211: Register frame type=0xd0 (WLAN_FC_STYPE_ACTION) nl_handle=0x558a43d5b0e0 match=0504
nl80211: Register frame type=0xd0 (WLAN_FC_STYPE_ACTION) nl_handle=0x558a43d5b0e0 match=06
nl80211: Register frame type=0xd0 (WLAN_FC_STYPE_ACTION) nl_handle=0x558a43d5b0e0 match=08
nl80211: Register frame type=0xd0 (WLAN_FC_STYPE_ACTION) nl_handle=0x558a43d5b0e0 match=09
nl80211: Register frame type=0xd0 (WLAN_FC_STYPE_ACTION) nl_handle=0x558a43d5b0e0 match=0a
nl80211: Register frame type=0xd0 (WLAN_FC_STYPE_ACTION) nl_handle=0x558a43d5b0e0 match=11
nl80211: Register frame type=0xd0 (WLAN_FC_STYPE_ACTION) nl_handle=0x558a43d5b0e0 match=7f
nl80211: Register frame type=0xb0 (WLAN_FC_STYPE_AUTH) nl_handle=0x558a43d5b0e0 match=
nl80211: Enable Probe Request reporting nl_preq=0x558a43d60710
nl80211: Register frame type=0x40 (WLAN_FC_STYPE_PROBE_REQ) nl_handle=0x558a43d60710 match=
rfkill: initial event: idx=0 type=1 op=0 soft=0 hard=0
nl80211: Add own interface ifindex 3 (ifidx_reason -1)
nl80211: if_indices[16]: 3(-1)
phy: phy0
BSS count 1, BSSID mask 00:00:00:00:00:00 (0 bits)
wifiap: interface state UNINITIALIZED->COUNTRY_UPDATE
Previous country code UA, new country code UAI
nl80211: Regulatory information - country=UA (DFS-ETSI)
nl80211: 2400-2483 @ 40 MHz 20 mBm (no outdoor)
nl80211: 5150-5250 @ 80 MHz 20 mBm (no outdoor)
nl80211: 5250-5350 @ 80 MHz 20 mBm (no outdoor) (DFS)
nl80211: 5490-5670 @ 160 MHz 20 mBm (DFS)
nl80211: 5735-5835 @ 80 MHz 20 mBm
nl80211: 57000-66000 @ 2160 MHz 40 mBm
nl80211: Added 802.11b mode based on 802.11g information
nl80211: Mode IEEE 802.11g: 2412 2417 2422 2427 2432 2437 2442 2447 2452 2457 2462 2467[NO_IR] 2472[NO_IR] 2484[DISABLED]
nl80211: Mode IEEE 802.11a: 5180 5200 5220 5240 5260[RADAR] 5280[RADAR] 5300[RADAR] 5320[RADAR] 5500[RADAR] 5520[RADAR] 5540[RADAR] 5560[RADAR] 5580[RADAR] 5600[RADAR] 5620[RADAR] 5640[RADAR] 5660[RADAR] 5680[RADAR]
nl80211: Mode IEEE 802.11b: 2412 2417 2422 2427 2432 2437 2442 2447 2452 2457 2462 2467[NO_IR] 2472[NO_IR] 2484[DISABLED]
Allowed channel: mode=1 chan=1 freq=2412 MHz max_tx_power=20 dBm
Allowed channel: mode=1 chan=2 freq=2417 MHz max_tx_power=20 dBm
Allowed channel: mode=1 chan=3 freq=2422 MHz max_tx_power=20 dBm
Allowed channel: mode=1 chan=4 freq=2427 MHz max_tx_power=20 dBm
Allowed channel: mode=1 chan=5 freq=2432 MHz max_tx_power=20 dBm
Allowed channel: mode=1 chan=6 freq=2437 MHz max_tx_power=20 dBm
Allowed channel: mode=1 chan=7 freq=2442 MHz max_tx_power=20 dBm
Allowed channel: mode=1 chan=8 freq=2447 MHz max_tx_power=20 dBm
Allowed channel: mode=1 chan=9 freq=2452 MHz max_tx_power=20 dBm
Allowed channel: mode=1 chan=10 freq=2457 MHz max_tx_power=20 dBm
Allowed channel: mode=1 chan=11 freq=2462 MHz max_tx_power=20 dBm
Allowed channel: mode=2 chan=36 freq=5180 MHz max_tx_power=20 dBm
Allowed channel: mode=2 chan=40 freq=5200 MHz max_tx_power=20 dBm
Allowed channel: mode=2 chan=44 freq=5220 MHz max_tx_power=20 dBm
Allowed channel: mode=2 chan=48 freq=5240 MHz max_tx_power=20 dBm
Allowed channel: mode=2 chan=149 freq=5745 MHz max_tx_power=20 dBm
Allowed channel: mode=2 chan=153 freq=5765 MHz max_tx_power=20 dBm
Allowed channel: mode=2 chan=157 freq=5785 MHz max_tx_power=20 dBm
Allowed channel: mode=2 chan=161 freq=5805 MHz max_tx_power=20 dBm
Allowed channel: mode=2 chan=165 freq=5825 MHz max_tx_power=20 dBm
Allowed channel: mode=0 chan=1 freq=2412 MHz max_tx_power=20 dBm
Allowed channel: mode=0 chan=2 freq=2417 MHz max_tx_power=20 dBm
Allowed channel: mode=0 chan=3 freq=2422 MHz max_tx_power=20 dBm
Allowed channel: mode=0 chan=4 freq=2427 MHz max_tx_power=20 dBm
Allowed channel: mode=0 chan=5 freq=2432 MHz max_tx_power=20 dBm
Allowed channel: mode=0 chan=6 freq=2437 MHz max_tx_power=20 dBm
Allowed channel: mode=0 chan=7 freq=2442 MHz max_tx_power=20 dBm
Allowed channel: mode=0 chan=8 freq=2447 MHz max_tx_power=20 dBm
Allowed channel: mode=0 chan=9 freq=2452 MHz max_tx_power=20 dBm
Allowed channel: mode=0 chan=10 freq=2457 MHz max_tx_power=20 dBm
Allowed channel: mode=0 chan=11 freq=2462 MHz max_tx_power=20 dBm
Channel 52 (primary) not allowed for AP mode, flags: 0x979 RADAR
wifiap: IEEE 802.11 Configured channel (52) not found from the channel list of current mode (2) IEEE 802.11a
wifiap: IEEE 802.11 Hardware does not support configured channel
Could not select hw_mode and channel. (-3)
wifiap: interface state COUNTRY_UPDATE->DISABLED
wifiap: AP-DISABLED 
wifiap: Unable to setup interface.
hostapd_interface_deinit_free(0x558a43d58bd0)
hostapd_interface_deinit_free: num_bss=1 conf->num_bss=1
hostapd_interface_deinit(0x558a43d58bd0)
wifiap: interface state DISABLED->DISABLED
hostapd_bss_deinit: deinit bss wifiap
wifiap: Deauthenticate all stations
nl80211: sta_remove -> DEL_STATION wifiap ff:ff:ff:ff:ff:ff --> -22 (Invalid argument)
wifiap: AP-DISABLED 
hostapd_cleanup(hapd=0x558a43d5a1d0 (wifiap))
wifiap: CTRL-EVENT-TERMINATING 
hostapd_free_hapd_data: Interface wifiap wasn't started
hostapd_interface_deinit_free: driver=0x558a4318ab20 drv_priv=0x558a43d5b5f0 -> hapd_deinit
nl80211: deinit ifname=wifiap disabled_11b_rates=0
nl80211: Disable Probe Request reporting nl_preq=0x8888dd02cb5e8f99
nl80211: Remove monitor interface: refcount=0
nl80211: Remove beacon (ifindex=3)
netlink: Operstate: ifindex=3 linkmode=0 (kernel-control), operstate=6 (IF_OPER_UP)
nl80211: Set mode ifindex 3 iftype 2 (STATION)
nl80211: Teardown AP(wifiap) - device_ap_sme=1 use_monitor=0
nl80211: Unsubscribe mgmt frames handle 0x8888dd02cb5d3869 (AP teardown (dev SME))
hostapd_interface_free(0x558a43d58bd0)
hostapd_interface_free: free hapd 0x558a43d5a1d0
hostapd_cleanup_iface(0x558a43d58bd0)
hostapd_cleanup_iface_partial(0x558a43d58bd0)
hostapd_cleanup_iface: free iface=0x558a43d58bd0

Code:

>lsusb
Bus 001 Device 004: ID 0bda:b812 Realtek Semiconductor Corp. RTL88x2bu [AC1200 Techkey]

Code:

>iw phy0 info
Wiphy phy0
	wiphy index: 0
	max # scan SSIDs: 9
	max scan IEs length: 2304 bytes
	max # sched scan SSIDs: 0
	max # match sets: 0
	max # scan plans: 1
	max scan plan interval: -1
	max scan plan iterations: 0
	Retry short limit: 7
	Retry long limit: 4
	Coverage class: 0 (up to 0m)
	Supported Ciphers:
		* WEP40 (00-0f-ac:1)
		* WEP104 (00-0f-ac:5)
		* TKIP (00-0f-ac:2)
		* CCMP-128 (00-0f-ac:4)
		* CMAC (00-0f-ac:6)
	Available Antennas: TX 0 RX 0
	Supported interface modes:
		 * IBSS
		 * managed
		 * AP
		 * P2P-client
		 * P2P-GO
	Band 1:
		Capabilities: 0x1963
			RX LDPC
			HT20/HT40
			Static SM Power Save
			RX HT20 SGI
			RX HT40 SGI
			RX STBC 1-stream
			Max AMSDU length: 7935 bytes
			DSSS/CCK HT40
		Maximum RX AMPDU length 65535 bytes (exponent: 0x003)
		Minimum RX AMPDU time spacing: 16 usec (0x07)
		HT Max RX data rate: 300 Mbps
		HT TX/RX MCS rate indexes supported: 0-15
		Bitrates (non-HT):
			* 1.0 Mbps
			* 2.0 Mbps
			* 5.5 Mbps
			* 11.0 Mbps
			* 6.0 Mbps
			* 9.0 Mbps
			* 12.0 Mbps
			* 18.0 Mbps
			* 24.0 Mbps
			* 36.0 Mbps
			* 48.0 Mbps
			* 54.0 Mbps
		Frequencies:
			* 2412 MHz [1] (20.0 dBm)
			* 2417 MHz [2] (20.0 dBm)
			* 2422 MHz [3] (20.0 dBm)
			* 2427 MHz [4] (20.0 dBm)
			* 2432 MHz [5] (20.0 dBm)
			* 2437 MHz [6] (20.0 dBm)
			* 2442 MHz [7] (20.0 dBm)
			* 2447 MHz [8] (20.0 dBm)
			* 2452 MHz [9] (20.0 dBm)
			* 2457 MHz [10] (20.0 dBm)
			* 2462 MHz [11] (20.0 dBm)
			* 2467 MHz [12] (20.0 dBm) (no IR)
			* 2472 MHz [13] (20.0 dBm) (no IR)
			* 2484 MHz [14] (disabled)
	Band 2:
		Capabilities: 0x1863
			RX LDPC
			HT20/HT40
			Static SM Power Save
			RX HT20 SGI
			RX HT40 SGI
			No RX STBC
			Max AMSDU length: 7935 bytes
			DSSS/CCK HT40
		Maximum RX AMPDU length 65535 bytes (exponent: 0x003)
		Minimum RX AMPDU time spacing: 16 usec (0x07)
		HT Max RX data rate: 300 Mbps
		HT TX/RX MCS rate indexes supported: 0-15
		VHT Capabilities (0x03d071b2):
			Max MPDU length: 11454
			Supported Channel Width: neither 160 nor 80+80
			RX LDPC
			short GI (80 MHz)
			TX STBC
			SU Beamformee
			MU Beamformee
			+HTC-VHT
		VHT RX MCS set:
			1 streams: MCS 0-9
			2 streams: MCS 0-9
			3 streams: not supported
			4 streams: not supported
			5 streams: not supported
			6 streams: not supported
			7 streams: not supported
			8 streams: not supported
		VHT RX highest supported: 867 Mbps
		VHT TX MCS set:
			1 streams: MCS 0-9
			2 streams: MCS 0-9
			3 streams: not supported
			4 streams: not supported
			5 streams: not supported
			6 streams: not supported
			7 streams: not supported
			8 streams: not supported
		VHT TX highest supported: 867 Mbps
		Bitrates (non-HT):
			* 6.0 Mbps
			* 9.0 Mbps
			* 12.0 Mbps
			* 18.0 Mbps
			* 24.0 Mbps
			* 36.0 Mbps
			* 48.0 Mbps
			* 54.0 Mbps
		Frequencies:
			* 5180 MHz [36] (20.0 dBm)
			* 5200 MHz [40] (20.0 dBm)
			* 5220 MHz [44] (20.0 dBm)
			* 5240 MHz [48] (20.0 dBm)
			* 5260 MHz [52] (20.0 dBm) (radar detection)
			* 5280 MHz [56] (20.0 dBm) (radar detection)
			* 5300 MHz [60] (20.0 dBm) (radar detection)
			* 5320 MHz [64] (20.0 dBm) (radar detection)
			* 5500 MHz [100] (20.0 dBm) (radar detection)
			* 5520 MHz [104] (20.0 dBm) (radar detection)
			* 5540 MHz [108] (20.0 dBm) (radar detection)
			* 5560 MHz [112] (20.0 dBm) (radar detection)
			* 5580 MHz [116] (20.0 dBm) (radar detection)
			* 5600 MHz [120] (20.0 dBm) (radar detection)
			* 5620 MHz [124] (20.0 dBm) (radar detection)
			* 5640 MHz [128] (20.0 dBm) (radar detection)
			* 5660 MHz [132] (20.0 dBm) (radar detection)
			* 5680 MHz [136] (30.0 dBm) (radar detection)
			* 5700 MHz [140] (30.0 dBm) (radar detection)
			* 5720 MHz [144] (disabled)
			* 5745 MHz [149] (20.0 dBm)
			* 5765 MHz [153] (20.0 dBm)
			* 5785 MHz [157] (20.0 dBm)
			* 5805 MHz [161] (20.0 dBm)
			* 5825 MHz [165] (20.0 dBm)
			* 5845 MHz [169] (disabled)
			* 5865 MHz [173] (disabled)
			* 5885 MHz [177] (disabled)
	Supported commands:
		 * new_interface
		 * set_interface
		 * new_key
		 * start_ap
		 * new_station
		 * set_bss
		 * join_ibss
		 * set_pmksa
		 * del_pmksa
		 * flush_pmksa
		 * remain_on_channel
		 * frame
		 * set_channel
		 * connect
		 * disconnect
	Supported TX frame types:
		 * IBSS: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
		 * managed: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
		 * AP: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
		 * AP/VLAN: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
		 * P2P-client: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
		 * P2P-GO: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
	Supported RX frame types:
		 * IBSS: 0xd0
		 * managed: 0x40 0xb0 0xd0
		 * AP: 0x00 0x20 0x40 0xa0 0xb0 0xc0 0xd0
		 * AP/VLAN: 0x00 0x20 0x40 0xa0 0xb0 0xc0 0xd0
		 * P2P-client: 0x40 0xd0
		 * P2P-GO: 0x00 0x20 0x40 0xa0 0xb0 0xc0 0xd0
	WoWLAN support:
		 * wake up on anything (device continues operating normally)
	software interface modes (can always be added):
	interface combinations are not supported
	Device supports SAE with AUTHENTICATE command
	Device supports scan flush.
	Supported extended features: