From 5615f7c8b3abded17febe19e0d4f9914b561285c Mon Sep 17 00:00:00 2001
From: dzou <dzou@company.com>
Date: Sun, 5 Jun 2022 23:22:49 +0800
Subject: [PATCH 908/911] DFS: Switch to background radar channel if available

On radar detection on the main chain switch to the channel monitored
by the background chain if we have already performed the CAC there.
If a radar pattern is reported on the background chain, just select a
new random channel according to the regulations for monitoring.

Tested-by: Owen Peng <owen.peng@mediatek.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
---
 src/ap/dfs.c | 65 ++++++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 58 insertions(+), 7 deletions(-)

diff --git a/src/ap/dfs.c b/src/ap/dfs.c
index 1224acd31..d63caaee3 100644
--- a/src/ap/dfs.c
+++ b/src/ap/dfs.c
@@ -1295,6 +1295,53 @@ static int hostapd_dfs_start_channel_switch_cac(struct hostapd_iface *iface)
 }
 
 
+static int
+hostapd_dfs_background_start_channel_switch(struct hostapd_iface *iface,
+					    int freq)
+{
+	if (!dfs_use_radar_background(iface))
+		return -1; /* Background radar chain not supported. */
+
+	wpa_printf(MSG_DEBUG,
+		   "%s called (background CAC active: %s, CSA active: %s)",
+		   __func__, iface->radar_background.cac_started ? "yes" : "no",
+		   hostapd_csa_in_progress(iface) ? "yes" : "no");
+
+	/* Check if CSA in progress */
+	if (hostapd_csa_in_progress(iface))
+		return 0;
+
+	if (hostapd_dfs_is_background_event(iface, freq)) {
+		/*
+		 * Radar pattern is reported on the background chain.
+		 * Just select a new random channel according to the
+		 * regulations for monitoring.
+		 */
+		hostpad_dfs_update_background_chain(iface);
+		return 0;
+	}
+
+	/*
+	 * If background radar detection is supported and the radar channel
+	 * monitored by the background chain is available switch to it without
+	 * waiting for the CAC.
+	 */
+	if (iface->radar_background.channel == -1)
+		return -1; /* Background radar chain not available. */
+
+	if (iface->radar_background.cac_started) {
+		/*
+		 * Background channel not available yet. Perform CAC on the
+		 * main chain.
+		 */
+		iface->radar_background.temp_ch = 1;
+		return -1;
+	}
+
+	return hostapd_dfs_start_channel_switch_background(iface);
+}
+
+
 static int hostapd_dfs_start_channel_switch(struct hostapd_iface *iface)
 {
 	struct hostapd_channel_data *channel;
@@ -1399,15 +1446,19 @@ int hostapd_dfs_radar_detected(struct hostapd_iface *iface, int freq,
 	if (!res)
 		return 0;
 
-	/* Skip if reported radar event not overlapped our channels */
-	res = dfs_are_channels_overlapped(iface, freq, chan_width, cf1, cf2);
-	if (!res)
-		return 0;
+	if (!hostapd_dfs_is_background_event(iface, freq)) {
+		/* Skip if reported radar event not overlapped our channels */
+		if (!dfs_are_channels_overlapped(iface, freq, chan_width,
+						 cf1, cf2))
+			return 0;
+	}
 
-	/* radar detected while operating, switch the channel. */
-	res = hostapd_dfs_start_channel_switch(iface);
+	if (hostapd_dfs_background_start_channel_switch(iface, freq)) {
+		/* Radar detected while operating, switch the channel. */
+		return hostapd_dfs_start_channel_switch(iface);
+	}
 
-	return res;
+	return 0;
 }
 
 
-- 
2.29.2