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, 120 insertions, 0 deletions

diff --git a/net/wireless/mlme.c b/net/wireless/mlme.c
index 8e69207..caddca3 100644
--- a/net/wireless/mlme.c
+++ b/net/wireless/mlme.c
@@ -987,3 +987,123 @@ void cfg80211_pmksa_candidate_notify(struct net_device *dev, int index,
 	nl80211_pmksa_candidate_notify(rdev, dev, index, bssid, preauth, gfp);
 }
 EXPORT_SYMBOL(cfg80211_pmksa_candidate_notify);
+
+void cfg80211_dfs_channels_update_work(struct work_struct *work)
+{
+	struct delayed_work *delayed_work;
+	struct cfg80211_registered_device *rdev;
+	struct cfg80211_chan_def chandef;
+	struct ieee80211_supported_band *sband;
+	struct ieee80211_channel *c;
+	struct wiphy *wiphy;
+	bool check_again = false;
+	unsigned long timeout, next_time = 0;
+	int bandid, i;
+
+	delayed_work = container_of(work, struct delayed_work, work);
+	rdev = container_of(delayed_work, struct cfg80211_registered_device,
+			    dfs_update_channels_wk);
+	wiphy = &rdev->wiphy;
+
+	mutex_lock(&cfg80211_mutex);
+	for (bandid = 0; bandid < IEEE80211_NUM_BANDS; bandid++) {
+		sband = wiphy->bands[bandid];
+		if (!sband)
+			continue;
+
+		for (i = 0; i < sband->n_channels; i++) {
+			c = &sband->channels[i];
+
+			if (c->dfs_state != NL80211_DFS_UNAVAILABLE)
+				continue;
+
+			timeout = c->dfs_state_entered +
+				  IEEE80211_DFS_MIN_NOP_TIME_MS;
+
+			if (time_after_eq(jiffies, timeout)) {
+				c->dfs_state = NL80211_DFS_USABLE;
+				cfg80211_chandef_create(&chandef, c,
+							NL80211_CHAN_NO_HT);
+
+				nl80211_radar_notify(rdev, &chandef,
+						     NL80211_RADAR_NOP_FINISHED,
+						     NULL, GFP_ATOMIC);
+				continue;
+			}
+
+			if (!check_again)
+				next_time = timeout - jiffies;
+			else
+				next_time = min(next_time, timeout - jiffies);
+			check_again = true;
+		}
+	}
+	mutex_unlock(&cfg80211_mutex);
+
+	/* reschedule if there are other channels waiting to be cleared again */
+	if (check_again)
+		queue_delayed_work(cfg80211_wq, &rdev->dfs_update_channels_wk,
+				   next_time);
+}
+
+
+void cfg80211_radar_event(struct wiphy *wiphy,
+			  struct cfg80211_chan_def *chandef,
+			  gfp_t gfp)
+{
+	struct cfg80211_registered_device *rdev = wiphy_to_dev(wiphy);
+	unsigned long timeout;
+
+	trace_cfg80211_radar_event(wiphy, chandef);
+
+	/* only set the chandef supplied channel to unavailable, in
+	 * case the radar is detected on only one of multiple channels
+	 * spanned by the chandef.
+	 */
+	cfg80211_set_dfs_state(wiphy, chandef, NL80211_DFS_UNAVAILABLE);
+
+	timeout = msecs_to_jiffies(IEEE80211_DFS_MIN_NOP_TIME_MS);
+	queue_delayed_work(cfg80211_wq, &rdev->dfs_update_channels_wk,
+			   timeout);
+
+	nl80211_radar_notify(rdev, chandef, NL80211_RADAR_DETECTED, NULL, gfp);
+}
+EXPORT_SYMBOL(cfg80211_radar_event);
+
+void cfg80211_cac_event(struct net_device *netdev,
+			enum nl80211_radar_event event, gfp_t gfp)
+{
+	struct wireless_dev *wdev = netdev->ieee80211_ptr;
+	struct wiphy *wiphy = wdev->wiphy;
+	struct cfg80211_registered_device *rdev = wiphy_to_dev(wiphy);
+	struct cfg80211_chan_def chandef;
+	unsigned long timeout;
+
+	trace_cfg80211_cac_event(netdev, event);
+
+	if (WARN_ON(!wdev->cac_started))
+		return;
+
+	if (WARN_ON(!wdev->channel))
+		return;
+
+	cfg80211_chandef_create(&chandef, wdev->channel, NL80211_CHAN_NO_HT);
+
+	switch (event) {
+	case NL80211_RADAR_CAC_FINISHED:
+		timeout = wdev->cac_start_time +
+			  msecs_to_jiffies(IEEE80211_DFS_MIN_CAC_TIME_MS);
+		WARN_ON(!time_after_eq(jiffies, timeout));
+		cfg80211_set_dfs_state(wiphy, &chandef, NL80211_DFS_AVAILABLE);
+		break;
+	case NL80211_RADAR_CAC_ABORTED:
+		break;
+	default:
+		WARN_ON(1);
+		return;
+	}
+	wdev->cac_started = false;
+
+	nl80211_radar_notify(rdev, &chandef, event, netdev, gfp);
+}
+EXPORT_SYMBOL(cfg80211_cac_event);