hostapd: Allow to switch to DFS channels if available

If DFS channels are marked as "available", an AP can switch to them
immediately without performing CAC. Therefore, the channel selection
function should consider these channels even though these are radar
channels.

Signed-hostap: Simon Wunderlich <sw@simonwunderlich.de>

src/ap/dfs.c

@@ -50,9 +50,11 @@ static int dfs_channel_available(struct hostapd_channel_data *chan,
 	/*
 	 * When radar detection happens, CSA is performed. However, there's no
 	 * time for CAC, so radar channels must be skipped when finding a new
-	 * channel for CSA.
+	 * channel for CSA, unless they are available for immediate use.
 	 */
-	if (skip_radar && chan->flag & HOSTAPD_CHAN_RADAR)
+	if (skip_radar && (chan->flag & HOSTAPD_CHAN_RADAR) &&
+	    ((chan->flag & HOSTAPD_CHAN_DFS_MASK) !=
+	     HOSTAPD_CHAN_DFS_AVAILABLE))
 		return 0;
 
 	if (chan->flag & HOSTAPD_CHAN_DISABLED)