[openwrt/openwrt] hostapd: introduce background_radar option

[LEDE Commits]

stintel pushed a commit to openwrt/openwrt.git, branch master:
https://git.openwrt.org/f2982bcc890d10f3a501b3a84fe18e99d1af1e2f

commit f2982bcc890d10f3a501b3a84fe18e99d1af1e2f
Author: Stijn Tintel <stijn at linux-ipv6.be>
AuthorDate: Mon Jun 6 16:36:27 2022 +0300

    hostapd: introduce background_radar option
    
    Introduce a new option background_radar to toggle hostapd's background
    radar feature. Enabling this allows DFS CAC to run on dedicated radio RF
    chains while the radio(s) are otherwise running normal AP activities on
    other channels.
    
    As OpenWrt configures hostapd to use a channel list even when a single
    channel is configured, using this feature requires a list of channels in
    /etc/config/wireless. Alternatively, channel can be set to auto.
    
    Signed-off-by: Stijn Tintel <stijn at linux-ipv6.be>
    Acked-by: David Bauer <mail at david-bauer.net>
---
 package/kernel/mac80211/files/lib/netifd/wireless/mac80211.sh | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/package/kernel/mac80211/files/lib/netifd/wireless/mac80211.sh b/package/kernel/mac80211/files/lib/netifd/wireless/mac80211.sh
index 3d0afb261f..3ffe6de66b 100644
--- a/package/kernel/mac80211/files/lib/netifd/wireless/mac80211.sh
+++ b/package/kernel/mac80211/files/lib/netifd/wireless/mac80211.sh
@@ -29,7 +29,7 @@ drv_mac80211_init_device_config() {
 	config_add_string distance
 	config_add_int beacon_int chanbw frag rts
 	config_add_int rxantenna txantenna antenna_gain txpower
-	config_add_boolean noscan ht_coex acs_exclude_dfs
+	config_add_boolean noscan ht_coex acs_exclude_dfs background_radar
 	config_add_array ht_capab
 	config_add_array channels
 	config_add_array scan_list
@@ -273,6 +273,11 @@ mac80211_hostapd_setup_base() {
 			vht_center_seg0=$idx
 		;;
 	esac
+	[ "$band" = "5g" ] && {
+		json_get_vars background_radar:0
+
+		[ "$background_radar" -eq 1 ] && append base_cfg "enable_background_radar=1" "$N"
+	}
 	[ "$band" = "6g" ] && {
 		op_class=
 		case "$htmode" in