1 files changed, 87 insertions, 7 deletions

diff --git a/net/wireless/chan.c b/net/wireless/chan.c
index dfb4893421d7..ceb9174c5c3d 100644
--- a/net/wireless/chan.c
+++ b/net/wireless/chan.c
@@ -515,9 +515,83 @@ static u32 cfg80211_get_end_freq(u32 center_freq,
 	return end_freq;
 }
 
+static bool
+cfg80211_dfs_permissive_check_wdev(struct cfg80211_registered_device *rdev,
+				   enum nl80211_iftype iftype,
+				   struct wireless_dev *wdev,
+				   struct ieee80211_channel *chan)
+{
+	unsigned int link_id;
+
+	for_each_valid_link(wdev, link_id) {
+		struct ieee80211_channel *other_chan = NULL;
+		struct cfg80211_chan_def chandef = {};
+		int ret;
+
+		/* In order to avoid daisy chaining only allow BSS STA */
+		if (wdev->iftype != NL80211_IFTYPE_STATION ||
+		    !wdev->links[link_id].client.current_bss)
+			continue;
+
+		other_chan =
+			wdev->links[link_id].client.current_bss->pub.channel;
+
+		if (!other_chan)
+			continue;
+
+		if (chan == other_chan)
+			return true;
+
+		/* continue if we can't get the channel */
+		ret = rdev_get_channel(rdev, wdev, link_id, &chandef);
+		if (ret)
+			continue;
+
+		if (cfg80211_is_sub_chan(&chandef, chan, false))
+			return true;
+	}
+
+	return false;
+}
+
+/*
+ * Check if P2P GO is allowed to operate on a DFS channel
+ */
+static bool cfg80211_dfs_permissive_chan(struct wiphy *wiphy,
+					 enum nl80211_iftype iftype,
+					 struct ieee80211_channel *chan)
+{
+	struct wireless_dev *wdev;
+	struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
+
+	lockdep_assert_held(&rdev->wiphy.mtx);
+
+	if (!wiphy_ext_feature_isset(&rdev->wiphy,
+				     NL80211_EXT_FEATURE_DFS_CONCURRENT) ||
+	    !(chan->flags & IEEE80211_CHAN_DFS_CONCURRENT))
+		return false;
+
+	/* only valid for P2P GO */
+	if (iftype != NL80211_IFTYPE_P2P_GO)
+		return false;
+
+	/*
+	 * Allow only if there's a concurrent BSS
+	 */
+	list_for_each_entry(wdev, &rdev->wiphy.wdev_list, list) {
+		bool ret = cfg80211_dfs_permissive_check_wdev(rdev, iftype,
+							      wdev, chan);
+		if (ret)
+			return ret;
+	}
+
+	return false;
+}
+
 static int cfg80211_get_chans_dfs_required(struct wiphy *wiphy,
 					    u32 center_freq,
-					    u32 bandwidth)
+					    u32 bandwidth,
+					    enum nl80211_iftype iftype)
 {
 	struct ieee80211_channel *c;
 	u32 freq, start_freq, end_freq;
@@ -530,9 +604,11 @@ static int cfg80211_get_chans_dfs_required(struct wiphy *wiphy,
 		if (!c)
 			return -EINVAL;
 
-		if (c->flags & IEEE80211_CHAN_RADAR)
+		if (c->flags & IEEE80211_CHAN_RADAR &&
+		    !cfg80211_dfs_permissive_chan(wiphy, iftype, c))
 			return 1;
 	}
+
 	return 0;
 }
 
@@ -558,7 +634,7 @@ int cfg80211_chandef_dfs_required(struct wiphy *wiphy,
 
 		ret = cfg80211_get_chans_dfs_required(wiphy,
 					ieee80211_chandef_to_khz(chandef),
-					width);
+					width, iftype);
 		if (ret < 0)
 			return ret;
 		else if (ret > 0)
@@ -569,7 +645,7 @@ int cfg80211_chandef_dfs_required(struct wiphy *wiphy,
 
 		ret = cfg80211_get_chans_dfs_required(wiphy,
 					MHZ_TO_KHZ(chandef->center_freq2),
-					width);
+					width, iftype);
 		if (ret < 0)
 			return ret;
 		else if (ret > 0)
@@ -1337,15 +1413,19 @@ static bool _cfg80211_reg_can_beacon(struct wiphy *wiphy,
 				     bool check_no_ir)
 {
 	bool res;
-	u32 prohibited_flags = IEEE80211_CHAN_DISABLED |
-			       IEEE80211_CHAN_RADAR;
+	u32 prohibited_flags = IEEE80211_CHAN_DISABLED;
+	int dfs_required;
 
 	trace_cfg80211_reg_can_beacon(wiphy, chandef, iftype, check_no_ir);
 
 	if (check_no_ir)
 		prohibited_flags |= IEEE80211_CHAN_NO_IR;
 
-	if (cfg80211_chandef_dfs_required(wiphy, chandef, iftype) > 0 &&
+	dfs_required = cfg80211_chandef_dfs_required(wiphy, chandef, iftype);
+	if (dfs_required != 0)
+		prohibited_flags |= IEEE80211_CHAN_RADAR;
+
+	if (dfs_required > 0 &&
 	    cfg80211_chandef_dfs_available(wiphy, chandef)) {
 		/* We can skip IEEE80211_CHAN_NO_IR if chandef dfs available */
 		prohibited_flags = IEEE80211_CHAN_DISABLED;