cfg80211: issue netlink notification when scan starts

To ease multiple apps working together smoothly,
send a notification when a scan is started.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

net/wireless/nl80211.c

@@ -2839,6 +2839,9 @@ static int nl80211_trigger_scan(struct sk_buff *skb, struct genl_info *info)
 	drv->scan_req = request;
 	err = drv->ops->scan(&drv->wiphy, dev, request);
 
+	if (!err)
+		nl80211_send_scan_start(drv, dev);
+
  out_free:
 	if (err) {
 		drv->scan_req = NULL;
@@ -3665,7 +3668,7 @@ static int nl80211_add_scan_req(struct sk_buff *msg,
 	return -ENOBUFS;
 }
 
-static int nl80211_send_scan_donemsg(struct sk_buff *msg,
+static int nl80211_send_scan_msg(struct sk_buff *msg,
 				 struct cfg80211_registered_device *rdev,
 				 struct net_device *netdev,
 				 u32 pid, u32 seq, int flags,
@@ -3690,6 +3693,24 @@ static int nl80211_send_scan_donemsg(struct sk_buff *msg,
 	return -EMSGSIZE;
 }
 
+void nl80211_send_scan_start(struct cfg80211_registered_device *rdev,
+			     struct net_device *netdev)
+{
+	struct sk_buff *msg;
+
+	msg = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
+	if (!msg)
+		return;
+
+	if (nl80211_send_scan_msg(msg, rdev, netdev, 0, 0, 0,
+				  NL80211_CMD_TRIGGER_SCAN) < 0) {
+		nlmsg_free(msg);
+		return;
+	}
+
+	genlmsg_multicast(msg, 0, nl80211_scan_mcgrp.id, GFP_KERNEL);
+}
+
 void nl80211_send_scan_done(struct cfg80211_registered_device *rdev,
 			    struct net_device *netdev)
 {
@@ -3699,7 +3720,7 @@ void nl80211_send_scan_done(struct cfg80211_registered_device *rdev,
 	if (!msg)
 		return;
 
-	if (nl80211_send_scan_donemsg(msg, rdev, netdev, 0, 0, 0,
+	if (nl80211_send_scan_msg(msg, rdev, netdev, 0, 0, 0,
 				  NL80211_CMD_NEW_SCAN_RESULTS) < 0) {
 		nlmsg_free(msg);
 		return;
@@ -3717,7 +3738,7 @@ void nl80211_send_scan_aborted(struct cfg80211_registered_device *rdev,
 	if (!msg)
 		return;
 
-	if (nl80211_send_scan_donemsg(msg, rdev, netdev, 0, 0, 0,
+	if (nl80211_send_scan_msg(msg, rdev, netdev, 0, 0, 0,
 				  NL80211_CMD_SCAN_ABORTED) < 0) {
 		nlmsg_free(msg);
 		return;

net/wireless/nl80211.h

@@ -6,6 +6,8 @@
 extern int nl80211_init(void);
 extern void nl80211_exit(void);
 extern void nl80211_notify_dev_rename(struct cfg80211_registered_device *rdev);
+extern void nl80211_send_scan_start(struct cfg80211_registered_device *rdev,
+				    struct net_device *netdev);
 extern void nl80211_send_scan_done(struct cfg80211_registered_device *rdev,
 				   struct net_device *netdev);
 extern void nl80211_send_scan_aborted(struct cfg80211_registered_device *rdev,

net/wireless/scan.c

@@ -647,7 +647,8 @@ int cfg80211_wext_siwscan(struct net_device *dev,
 	if (err) {
 		rdev->scan_req = NULL;
 		kfree(creq);
-	}
+	} else
+		nl80211_send_scan_start(rdev, dev);
  out:
 	cfg80211_put_dev(rdev);
 	return err;