cfg80211: Make pre-CAC results valid only for ETSI domain

DFS requirement for ETSI domain (section 4.7.1.4 in
ETSI EN 301 893 V1.8.1) is the only one which explicitly
states that once DFS channel is marked as available afer
the CAC, this channel will remain in available state even
moving to a different operating channel. But the same is
not explicitly stated in FCC DFS requirement. Also, Pre-CAC
requriements are not explicitly mentioned in FCC requirement.
Current implementation in keeping DFS channel in available
state is same as described in ETSI domain.

For non-ETSI DFS domain, this patch gives a grace period of 2 seconds
since the completion of successful CAC before moving the channel's
DFS state to 'usable' from 'available' state. The same grace period
is checked against the channel's dfs_state_entered timestamp while
deciding if a DFS channel is available for operation. There is a new
radar event, NL80211_RADAR_PRE_CAC_EXPIRED, reported when DFS channel
is moved from available to usable state after the grace period. Also
make sure the DFS channel state is reset to usable once the beaconing
operation on that channel is brought down (like stop_ap, leave_ibss
and leave_mesh) in non-ETSI domain.

Signed-off-by: Vasanthakumar Thiagarajan <vthiagar@qti.qualcomm.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 101 insertions, 0 deletions

diff --git a/net/wireless/chan.c b/net/wireless/chan.c
index 5497d022fada..099f13c0c39e 100644
--- a/net/wireless/chan.c
+++ b/net/wireless/chan.c
@@ -456,6 +456,107 @@ bool cfg80211_chandef_dfs_usable(struct wiphy *wiphy,
 	return (r1 + r2 > 0);
 }
 
+/*
+ * Checks if center frequency of chan falls with in the bandwidth
+ * range of chandef.
+ */
+bool cfg80211_is_sub_chan(struct cfg80211_chan_def *chandef,
+			  struct ieee80211_channel *chan)
+{
+	int width;
+	u32 cf_offset, freq;
+
+	if (chandef->chan->center_freq == chan->center_freq)
+		return true;
+
+	width = cfg80211_chandef_get_width(chandef);
+	if (width <= 20)
+		return false;
+
+	cf_offset = width / 2 - 10;
+
+	for (freq = chandef->center_freq1 - width / 2 + 10;
+	     freq <= chandef->center_freq1 + width / 2 - 10; freq += 20) {
+		if (chan->center_freq == freq)
+			return true;
+	}
+
+	if (!chandef->center_freq2)
+		return false;
+
+	for (freq = chandef->center_freq2 - width / 2 + 10;
+	     freq <= chandef->center_freq2 + width / 2 - 10; freq += 20) {
+		if (chan->center_freq == freq)
+			return true;
+	}
+
+	return false;
+}
+
+bool cfg80211_beaconing_iface_active(struct wireless_dev *wdev)
+{
+	bool active = false;
+
+	ASSERT_WDEV_LOCK(wdev);
+
+	if (!wdev->chandef.chan)
+		return false;
+
+	switch (wdev->iftype) {
+	case NL80211_IFTYPE_AP:
+	case NL80211_IFTYPE_P2P_GO:
+		active = wdev->beacon_interval != 0;
+		break;
+	case NL80211_IFTYPE_ADHOC:
+		active = wdev->ssid_len != 0;
+		break;
+	case NL80211_IFTYPE_MESH_POINT:
+		active = wdev->mesh_id_len != 0;
+		break;
+	case NL80211_IFTYPE_STATION:
+	case NL80211_IFTYPE_OCB:
+	case NL80211_IFTYPE_P2P_CLIENT:
+	case NL80211_IFTYPE_MONITOR:
+	case NL80211_IFTYPE_AP_VLAN:
+	case NL80211_IFTYPE_WDS:
+	case NL80211_IFTYPE_P2P_DEVICE:
+	/* Can NAN type be considered as beaconing interface? */
+	case NL80211_IFTYPE_NAN:
+		break;
+	case NL80211_IFTYPE_UNSPECIFIED:
+	case NUM_NL80211_IFTYPES:
+		WARN_ON(1);
+	}
+
+	return active;
+}
+
+bool cfg80211_any_wiphy_oper_chan(struct wiphy *wiphy,
+				  struct ieee80211_channel *chan)
+{
+	struct wireless_dev *wdev;
+
+	ASSERT_RTNL();
+
+	if (!(chan->flags & IEEE80211_CHAN_RADAR))
+		return false;
+
+	list_for_each_entry(wdev, &wiphy->wdev_list, list) {
+		wdev_lock(wdev);
+		if (!cfg80211_beaconing_iface_active(wdev)) {
+			wdev_unlock(wdev);
+			continue;
+		}
+
+		if (cfg80211_is_sub_chan(&wdev->chandef, chan)) {
+			wdev_unlock(wdev);
+			return true;
+		}
+		wdev_unlock(wdev);
+	}
+
+	return false;
+}
 
 static bool cfg80211_get_chans_dfs_available(struct wiphy *wiphy,
 					     u32 center_freq,