cfg80211: Share Channel DFS state across wiphys of same DFS domain

Sharing DFS channel state across multiple wiphys (radios) could
be useful with multiple radios on the system. When one radio
completes CAC and markes the channel available another radio
can use this information and start beaconing without really doing
CAC.

Whenever there is a state change in dfs channel associated to
a particular wiphy the the same state change is propagated to
other wiphys having the same DFS reg domain configuration.
Also when a new wiphy is created the dfs channel state of
other existing wiphys of same DFS domain is copied.

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

1 files changed, 120 insertions, 0 deletions

diff --git a/net/wireless/reg.c b/net/wireless/reg.c
index e59b192459e8..a38f315819cd 100644
--- a/net/wireless/reg.c
+++ b/net/wireless/reg.c
@@ -2067,6 +2067,88 @@ reg_process_hint_country_ie(struct wiphy *wiphy,
 	return REG_REQ_IGNORE;
 }
 
+bool reg_dfs_domain_same(struct wiphy *wiphy1, struct wiphy *wiphy2)
+{
+	const struct ieee80211_regdomain *wiphy1_regd = NULL;
+	const struct ieee80211_regdomain *wiphy2_regd = NULL;
+	const struct ieee80211_regdomain *cfg80211_regd = NULL;
+	bool dfs_domain_same;
+
+	rcu_read_lock();
+
+	cfg80211_regd = rcu_dereference(cfg80211_regdomain);
+	wiphy1_regd = rcu_dereference(wiphy1->regd);
+	if (!wiphy1_regd)
+		wiphy1_regd = cfg80211_regd;
+
+	wiphy2_regd = rcu_dereference(wiphy2->regd);
+	if (!wiphy2_regd)
+		wiphy2_regd = cfg80211_regd;
+
+	dfs_domain_same = wiphy1_regd->dfs_region == wiphy2_regd->dfs_region;
+
+	rcu_read_unlock();
+
+	return dfs_domain_same;
+}
+
+static void reg_copy_dfs_chan_state(struct ieee80211_channel *dst_chan,
+				    struct ieee80211_channel *src_chan)
+{
+	if (!(dst_chan->flags & IEEE80211_CHAN_RADAR) ||
+	    !(src_chan->flags & IEEE80211_CHAN_RADAR))
+		return;
+
+	if (dst_chan->flags & IEEE80211_CHAN_DISABLED ||
+	    src_chan->flags & IEEE80211_CHAN_DISABLED)
+		return;
+
+	if (src_chan->center_freq == dst_chan->center_freq &&
+	    dst_chan->dfs_state == NL80211_DFS_USABLE) {
+		dst_chan->dfs_state = src_chan->dfs_state;
+		dst_chan->dfs_state_entered = src_chan->dfs_state_entered;
+	}
+}
+
+static void wiphy_share_dfs_chan_state(struct wiphy *dst_wiphy,
+				       struct wiphy *src_wiphy)
+{
+	struct ieee80211_supported_band *src_sband, *dst_sband;
+	struct ieee80211_channel *src_chan, *dst_chan;
+	int i, j, band;
+
+	if (!reg_dfs_domain_same(dst_wiphy, src_wiphy))
+		return;
+
+	for (band = 0; band < NUM_NL80211_BANDS; band++) {
+		dst_sband = dst_wiphy->bands[band];
+		src_sband = src_wiphy->bands[band];
+		if (!dst_sband || !src_sband)
+			continue;
+
+		for (i = 0; i < dst_sband->n_channels; i++) {
+			dst_chan = &dst_sband->channels[i];
+			for (j = 0; j < src_sband->n_channels; j++) {
+				src_chan = &src_sband->channels[j];
+				reg_copy_dfs_chan_state(dst_chan, src_chan);
+			}
+		}
+	}
+}
+
+static void wiphy_all_share_dfs_chan_state(struct wiphy *wiphy)
+{
+	struct cfg80211_registered_device *rdev;
+
+	ASSERT_RTNL();
+
+	list_for_each_entry(rdev, &cfg80211_rdev_list, list) {
+		if (wiphy == &rdev->wiphy)
+			continue;
+		wiphy_share_dfs_chan_state(wiphy, &rdev->wiphy);
+	}
+}
+
 /* This processes *all* regulatory hints */
 static void reg_process_hint(struct regulatory_request *reg_request)
 {
@@ -2110,6 +2192,7 @@ static void reg_process_hint(struct regulatory_request *reg_request)
 	if (treatment == REG_REQ_ALREADY_SET && wiphy &&
 	    wiphy->regulatory_flags & REGULATORY_STRICT_REG) {
 		wiphy_update_regulatory(wiphy, reg_request->initiator);
+		wiphy_all_share_dfs_chan_state(wiphy);
 		reg_check_channels();
 	}
 
@@ -3061,6 +3144,7 @@ void wiphy_regulatory_register(struct wiphy *wiphy)
 
 	lr = get_last_request();
 	wiphy_update_regulatory(wiphy, lr->initiator);
+	wiphy_all_share_dfs_chan_state(wiphy);
 }
 
 void wiphy_regulatory_deregister(struct wiphy *wiphy)
@@ -3148,6 +3232,42 @@ bool regulatory_pre_cac_allowed(struct wiphy *wiphy)
 	return pre_cac_allowed;
 }
 
+void regulatory_propagate_dfs_state(struct wiphy *wiphy,
+				    struct cfg80211_chan_def *chandef,
+				    enum nl80211_dfs_state dfs_state,
+				    enum nl80211_radar_event event)
+{
+	struct cfg80211_registered_device *rdev;
+
+	ASSERT_RTNL();
+
+	if (WARN_ON(!cfg80211_chandef_valid(chandef)))
+		return;
+
+	if (WARN_ON(!(chandef->chan->flags & IEEE80211_CHAN_RADAR)))
+		return;
+
+	list_for_each_entry(rdev, &cfg80211_rdev_list, list) {
+		if (wiphy == &rdev->wiphy)
+			continue;
+
+		if (!reg_dfs_domain_same(wiphy, &rdev->wiphy))
+			continue;
+
+		if (!ieee80211_get_channel(&rdev->wiphy,
+					   chandef->chan->center_freq))
+			continue;
+
+		cfg80211_set_dfs_state(&rdev->wiphy, chandef, dfs_state);
+
+		if (event == NL80211_RADAR_DETECTED ||
+		    event == NL80211_RADAR_CAC_FINISHED)
+			cfg80211_sched_dfs_chan_update(rdev);
+
+		nl80211_radar_notify(rdev, chandef, event, NULL, GFP_KERNEL);
+	}
+}
+
 int __init regulatory_init(void)
 {
 	int err = 0;