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 d706bf3badc8..5cfa579df476 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 0663945cfa48..49a7c53a48ca 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);