cfg80211: add channel switch started notification

Add a new NL80211_CH_SWITCH_STARTED_NOTIFY message that can be sent to
the userspace when a channel switch process has started.  This allows
userspace to take action, for instance, by requesting other interfaces
to switch channel as necessary.

This patch introduces a function that allows the drivers to send this
notification.  It should be used when the driver starts processing a
channel switch initiated by a remote device (eg. when a STA receives a
CSA from the AP) and when it successfully starts a userspace-triggered
channel switch (eg. when hostapd triggers a channel swith in the AP).

Signed-off-by: Luciano Coelho <luciano.coelho@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 25 insertions, 3 deletions

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 24549cb..24fd292 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -11653,7 +11653,9 @@ EXPORT_SYMBOL(cfg80211_pmksa_candidate_notify);
 static void nl80211_ch_switch_notify(struct cfg80211_registered_device *rdev,
 				     struct net_device *netdev,
 				     struct cfg80211_chan_def *chandef,
-				     gfp_t gfp)
+				     gfp_t gfp,
+				     enum nl80211_commands notif,
+				     u8 count)
 {
 	struct sk_buff *msg;
 	void *hdr;
@@ -11662,7 +11664,7 @@ static void nl80211_ch_switch_notify(struct cfg80211_registered_device *rdev,
 	if (!msg)
 		return;
 
-	hdr = nl80211hdr_put(msg, 0, 0, 0, NL80211_CMD_CH_SWITCH_NOTIFY);
+	hdr = nl80211hdr_put(msg, 0, 0, 0, notif);
 	if (!hdr) {
 		nlmsg_free(msg);
 		return;
@@ -11674,6 +11676,10 @@ static void nl80211_ch_switch_notify(struct cfg80211_registered_device *rdev,
 	if (nl80211_send_chandef(msg, chandef))
 		goto nla_put_failure;
 
+	if ((notif == NL80211_CMD_CH_SWITCH_STARTED_NOTIFY) &&
+	    (nla_put_u32(msg, NL80211_ATTR_CH_SWITCH_COUNT, count)))
+			goto nla_put_failure;
+
 	genlmsg_end(msg, hdr);
 
 	genlmsg_multicast_netns(&nl80211_fam, wiphy_net(&rdev->wiphy), msg, 0,
@@ -11704,10 +11710,26 @@ void cfg80211_ch_switch_notify(struct net_device *dev,
 
 	wdev->chandef = *chandef;
 	wdev->preset_chandef = *chandef;
-	nl80211_ch_switch_notify(rdev, dev, chandef, GFP_KERNEL);
+	nl80211_ch_switch_notify(rdev, dev, chandef, GFP_KERNEL,
+				 NL80211_CMD_CH_SWITCH_NOTIFY, 0);
 }
 EXPORT_SYMBOL(cfg80211_ch_switch_notify);
 
+void cfg80211_ch_switch_started_notify(struct net_device *dev,
+				       struct cfg80211_chan_def *chandef,
+				       u8 count)
+{
+	struct wireless_dev *wdev = dev->ieee80211_ptr;
+	struct wiphy *wiphy = wdev->wiphy;
+	struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
+
+	trace_cfg80211_ch_switch_started_notify(dev, chandef);
+
+	nl80211_ch_switch_notify(rdev, dev, chandef, GFP_KERNEL,
+				 NL80211_CMD_CH_SWITCH_STARTED_NOTIFY, count);
+}
+EXPORT_SYMBOL(cfg80211_ch_switch_started_notify);
+
 void cfg80211_cqm_txe_notify(struct net_device *dev,
 			     const u8 *peer, u32 num_packets,
 			     u32 rate, u32 intvl, gfp_t gfp)