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>

2 files changed, 28 insertions, 8 deletions

diff --git a/include/linux/nl80211.h b/include/linux/nl80211.h
index d706bf3..5cfa579 100644
--- a/include/linux/nl80211.h
+++ b/include/linux/nl80211.h
@@ -358,11 +358,16 @@
  *	user space application). %NL80211_ATTR_FRAME is used to specify the
  *	frame contents (including header). %NL80211_ATTR_WIPHY_FREQ (and
  *	optionally %NL80211_ATTR_WIPHY_CHANNEL_TYPE) is used to indicate on
- *	which channel the frame is to be transmitted or was received. This
- *	channel has to be the current channel (remain-on-channel or the
- *	operational channel). When called, this operation returns a cookie
- *	(%NL80211_ATTR_COOKIE) that will be included with the TX status event
- *	pertaining to the TX request.
+ *	which channel the frame is to be transmitted or was received. If this
+ *	channel is not the current channel (remain-on-channel or the
+ *	operational channel) the device will switch to the given channel and
+ *	transmit the frame, optionally waiting for a response for the time
+ *	specified using %NL80211_ATTR_DURATION. When called, this operation
+ *	returns a cookie (%NL80211_ATTR_COOKIE) that will be included with the
+ *	TX status event pertaining to the TX request.
+ * @NL80211_CMD_FRAME_WAIT_CANCEL: When an off-channel TX was requested, this
+ *	command may be used with the corresponding cookie to cancel the wait
+ *	time if it is known that it is no longer necessary.
  * @NL80211_CMD_ACTION: Alias for @NL80211_CMD_FRAME for backward compatibility.
  * @NL80211_CMD_FRAME_TX_STATUS: Report TX status of a management frame
  *	transmitted with %NL80211_CMD_FRAME. %NL80211_ATTR_COOKIE identifies
@@ -493,6 +498,8 @@ enum nl80211_commands {
 	NL80211_CMD_SET_CHANNEL,
 	NL80211_CMD_SET_WDS_PEER,
 
+	NL80211_CMD_FRAME_WAIT_CANCEL,
+
 	/* add new commands above here */
 
 	/* used to define NL80211_CMD_MAX below */
@@ -828,6 +835,12 @@ enum nl80211_commands {
  *
  * @NL80211_ATTR_MCAST_RATE: Multicast tx rate (in 100 kbps) for IBSS
  *
+ * @NL80211_ATTR_OFFCHANNEL_TX_OK: For management frame TX, the frame may be
+ *	transmitted on another channel when the channel given doesn't match
+ *	the current channel. If the current channel doesn't match and this
+ *	flag isn't set, the frame will be rejected. This is also used as an
+ *	nl80211 capability flag.
+ *
  * @NL80211_ATTR_MAX: highest attribute number currently defined
  * @__NL80211_ATTR_AFTER_LAST: internal use
  */
@@ -1002,6 +1015,8 @@ enum nl80211_attrs {
 
 	NL80211_ATTR_MCAST_RATE,
 
+	NL80211_ATTR_OFFCHANNEL_TX_OK,
+
 	/* add attributes here, update the policy in nl80211.c */
 
 	__NL80211_ATTR_AFTER_LAST,
diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 0663945..49a7c53 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -1134,7 +1134,9 @@ struct cfg80211_pmksa {
  * @cancel_remain_on_channel: Cancel an on-going remain-on-channel operation.
  *	This allows the operation to be terminated prior to timeout based on
  *	the duration value.
- * @mgmt_tx: Transmit a management frame
+ * @mgmt_tx: Transmit a management frame.
+ * @mgmt_tx_cancel_wait: Cancel the wait time from transmitting a management
+ *	frame on another channel
  *
  * @testmode_cmd: run a test mode command
  *
@@ -1291,10 +1293,13 @@ struct cfg80211_ops {
 					    u64 cookie);
 
 	int	(*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);
+	int	(*mgmt_tx_cancel_wait)(struct wiphy *wiphy,
+				       struct net_device *dev,
+				       u64 cookie);
 
 	int	(*set_power_mgmt)(struct wiphy *wiphy, struct net_device *dev,
 				  bool enabled, int timeout);