nl80211/cfg80211: extend mgmt-tx API for off-channel

With p2p, it is sometimes necessary to transmit
a frame (typically an action frame) on another
channel than the current channel. Enable this
through the CMD_FRAME API, and allow it to wait
for a response. A new command allows that wait
to be aborted.

However, allow userspace to specify whether or
not it wants to allow off-channel TX, it may
actually want to use the same channel only.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 0c54407..aac2d7d 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -1552,9 +1552,9 @@
 }
 
 static int ieee80211_mgmt_tx(struct wiphy *wiphy, struct net_device *dev,
-			     struct ieee80211_channel *chan,
+			     struct ieee80211_channel *chan, bool offchan,
 			     enum nl80211_channel_type channel_type,
-			     bool channel_type_valid,
+			     bool channel_type_valid, unsigned int wait,
 			     const u8 *buf, size_t len, u64 *cookie)
 {
 	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
@@ -1565,6 +1565,9 @@
 	u32 flags = IEEE80211_TX_INTFL_NL80211_FRAME_TX |
 		    IEEE80211_TX_CTL_REQ_TX_STATUS;
 
+	if (offchan)
+		return -EOPNOTSUPP;
+
 	/* Check that we are on the requested channel for transmission */
 	if (chan != local->tmp_channel &&
 	    chan != local->oper_channel)