cfg80211: Fix radar event during another phy CAC

In case a radar event of CAC_FINISHED or RADAR_DETECTED
happens during another phy is during CAC we might need
to cancel that CAC.

If we got a radar in a channel that another phy is now
doing CAC on then the CAC should be canceled there.

If, for example, 2 phys doing CAC on the same channels,
or on comptable channels, once on of them will finish his
CAC the other might need to cancel his CAC, since it is no
longer relevant.

To fix that the commit adds an callback and implement it in
mac80211 to end CAC.
This commit also adds a call to said callback if after a radar
event we see the CAC is no longer relevant

Signed-off-by: Orr Mazor <Orr.Mazor@tandemg.com>
Reviewed-by: Sergey Matyukevich <sergey.matyukevich.os@quantenna.com>
Link: https://lore.kernel.org/r/20191222145449.15792-1-Orr.Mazor@tandemg.com
[slightly reformat/reword commit message]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 22 insertions, 1 deletions

diff --git a/net/wireless/reg.c b/net/wireless/reg.c
index 3c2070040277..fff9a74891fc 100644
--- a/net/wireless/reg.c
+++ b/net/wireless/reg.c
@@ -3892,6 +3892,25 @@ bool regulatory_pre_cac_allowed(struct wiphy *wiphy)
 }
 EXPORT_SYMBOL(regulatory_pre_cac_allowed);
 
+static void cfg80211_check_and_end_cac(struct cfg80211_registered_device *rdev)
+{
+	struct wireless_dev *wdev;
+	/* If we finished CAC or received radar, we should end any
+	 * CAC running on the same channels.
+	 * the check !cfg80211_chandef_dfs_usable contain 2 options:
+	 * either all channels are available - those the CAC_FINISHED
+	 * event has effected another wdev state, or there is a channel
+	 * in unavailable state in wdev chandef - those the RADAR_DETECTED
+	 * event has effected another wdev state.
+	 * In both cases we should end the CAC on the wdev.
+	 */
+	list_for_each_entry(wdev, &rdev->wiphy.wdev_list, list) {
+		if (wdev->cac_started &&
+		    !cfg80211_chandef_dfs_usable(&rdev->wiphy, &wdev->chandef))
+			rdev_end_cac(rdev, wdev->netdev);
+	}
+}
+
 void regulatory_propagate_dfs_state(struct wiphy *wiphy,
 				    struct cfg80211_chan_def *chandef,
 				    enum nl80211_dfs_state dfs_state,
@@ -3918,8 +3937,10 @@ void regulatory_propagate_dfs_state(struct wiphy *wiphy,
 		cfg80211_set_dfs_state(&rdev->wiphy, chandef, dfs_state);
 
 		if (event == NL80211_RADAR_DETECTED ||
-		    event == NL80211_RADAR_CAC_FINISHED)
+		    event == NL80211_RADAR_CAC_FINISHED) {
 			cfg80211_sched_dfs_chan_update(rdev);
+			cfg80211_check_and_end_cac(rdev);
+		}
 
 		nl80211_radar_notify(rdev, chandef, event, NULL, GFP_KERNEL);
 	}