nl80211/cfg80211: add radar detection command/event

Add new NL80211_CMD_RADAR_DETECT, which starts the Channel
Availability Check (CAC). This command will also notify the
usermode about events (CAC finished, CAC aborted, radar
detected, NOP finished).
Once radar detection has started it should continuously
monitor for radars as long as the channel is active.

This patch enables DFS for AP mode in nl80211/cfg80211.

Based on original patch by Victor Goldenshtein <victorg@ti.com>

Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
[remove WIPHY_FLAG_HAS_RADAR_DETECT again -- my mistake]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 127 insertions, 2 deletions

diff --git a/net/wireless/chan.c b/net/wireless/chan.c
index 396373f3ec26..810c23cfb894 100644
--- a/net/wireless/chan.c
+++ b/net/wireless/chan.c
@@ -147,6 +147,32 @@ static void chandef_primary_freqs(const struct cfg80211_chan_def *c,
 	}
 }
 
+static int cfg80211_chandef_get_width(const struct cfg80211_chan_def *c)
+{
+	int width;
+
+	switch (c->width) {
+	case NL80211_CHAN_WIDTH_20:
+	case NL80211_CHAN_WIDTH_20_NOHT:
+		width = 20;
+		break;
+	case NL80211_CHAN_WIDTH_40:
+		width = 40;
+		break;
+	case NL80211_CHAN_WIDTH_80P80:
+	case NL80211_CHAN_WIDTH_80:
+		width = 80;
+		break;
+	case NL80211_CHAN_WIDTH_160:
+		width = 160;
+		break;
+	default:
+		WARN_ON_ONCE(1);
+		return -1;
+	}
+	return width;
+}
+
 const struct cfg80211_chan_def *
 cfg80211_chandef_compatible(const struct cfg80211_chan_def *c1,
 			    const struct cfg80211_chan_def *c2)
@@ -192,6 +218,93 @@ cfg80211_chandef_compatible(const struct cfg80211_chan_def *c1,
 }
 EXPORT_SYMBOL(cfg80211_chandef_compatible);
 
+static void cfg80211_set_chans_dfs_state(struct wiphy *wiphy, u32 center_freq,
+					 u32 bandwidth,
+					 enum nl80211_dfs_state dfs_state)
+{
+	struct ieee80211_channel *c;
+	u32 freq;
+
+	for (freq = center_freq - bandwidth/2 + 10;
+	     freq <= center_freq + bandwidth/2 - 10;
+	     freq += 20) {
+		c = ieee80211_get_channel(wiphy, freq);
+		if (!c || !(c->flags & IEEE80211_CHAN_RADAR))
+			continue;
+
+		c->dfs_state = dfs_state;
+		c->dfs_state_entered = jiffies;
+	}
+}
+
+void cfg80211_set_dfs_state(struct wiphy *wiphy,
+			    const struct cfg80211_chan_def *chandef,
+			    enum nl80211_dfs_state dfs_state)
+{
+	int width;
+
+	if (WARN_ON(!cfg80211_chandef_valid(chandef)))
+		return;
+
+	width = cfg80211_chandef_get_width(chandef);
+	if (width < 0)
+		return;
+
+	cfg80211_set_chans_dfs_state(wiphy, chandef->center_freq1,
+				     width, dfs_state);
+
+	if (!chandef->center_freq2)
+		return;
+	cfg80211_set_chans_dfs_state(wiphy, chandef->center_freq2,
+				     width, dfs_state);
+}
+
+static int cfg80211_get_chans_dfs_required(struct wiphy *wiphy,
+					    u32 center_freq,
+					    u32 bandwidth)
+{
+	struct ieee80211_channel *c;
+	u32 freq;
+
+	for (freq = center_freq - bandwidth/2 + 10;
+	     freq <= center_freq + bandwidth/2 - 10;
+	     freq += 20) {
+		c = ieee80211_get_channel(wiphy, freq);
+		if (!c)
+			return -EINVAL;
+
+		if (c->flags & IEEE80211_CHAN_RADAR)
+			return 1;
+	}
+	return 0;
+}
+
+
+int cfg80211_chandef_dfs_required(struct wiphy *wiphy,
+				  const struct cfg80211_chan_def *chandef)
+{
+	int width;
+	int r;
+
+	if (WARN_ON(!cfg80211_chandef_valid(chandef)))
+		return -EINVAL;
+
+	width = cfg80211_chandef_get_width(chandef);
+	if (width < 0)
+		return -EINVAL;
+
+	r = cfg80211_get_chans_dfs_required(wiphy, chandef->center_freq1,
+					    width);
+	if (r)
+		return r;
+
+	if (!chandef->center_freq2)
+		return 0;
+
+	return cfg80211_get_chans_dfs_required(wiphy, chandef->center_freq2,
+					       width);
+}
+
 static bool cfg80211_secondary_chans_ok(struct wiphy *wiphy,
 					u32 center_freq, u32 bandwidth,
 					u32 prohibited_flags)
@@ -203,7 +316,16 @@ static bool cfg80211_secondary_chans_ok(struct wiphy *wiphy,
 	     freq <= center_freq + bandwidth/2 - 10;
 	     freq += 20) {
 		c = ieee80211_get_channel(wiphy, freq);
-		if (!c || c->flags & prohibited_flags)
+		if (!c)
+			return false;
+
+		/* check for radar flags */
+		if ((prohibited_flags & c->flags & IEEE80211_CHAN_RADAR) &&
+		    (c->dfs_state != NL80211_DFS_AVAILABLE))
+			return false;
+
+		/* check for the other flags */
+		if (c->flags & prohibited_flags & ~IEEE80211_CHAN_RADAR)
 			return false;
 	}
 
@@ -344,7 +466,10 @@ cfg80211_get_chan_state(struct wireless_dev *wdev,
 		break;
 	case NL80211_IFTYPE_AP:
 	case NL80211_IFTYPE_P2P_GO:
-		if (wdev->beacon_interval) {
+		if (wdev->cac_started) {
+			*chan = wdev->channel;
+			*chanmode = CHAN_MODE_SHARED;
+		} else if (wdev->beacon_interval) {
 			*chan = wdev->channel;
 			*chanmode = CHAN_MODE_SHARED;
 		}