mac80211: sync driver before TX

In P2P client mode, the GO (AP) to connect to might
have periods of time where it is not available due
to powersave. To allow the driver to sync with it
and send frames to the GO only when it is available
add a new callback tx_sync (and the corresponding
finish_tx_sync). These callbacks can sleep unlike
the actual TX.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 42 insertions, 0 deletions

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 972109f..9259e97 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -1586,6 +1586,20 @@ enum ieee80211_ampdu_mlme_action {
 };
 
 /**
+ * enum ieee80211_tx_sync_type - TX sync type
+ * @IEEE80211_TX_SYNC_AUTH: sync TX for authentication
+ *	(and possibly also before direct probe)
+ * @IEEE80211_TX_SYNC_ASSOC: sync TX for association
+ * @IEEE80211_TX_SYNC_ACTION: sync TX for action frame
+ *	(not implemented yet)
+ */
+enum ieee80211_tx_sync_type {
+	IEEE80211_TX_SYNC_AUTH,
+	IEEE80211_TX_SYNC_ASSOC,
+	IEEE80211_TX_SYNC_ACTION,
+};
+
+/**
  * struct ieee80211_ops - callbacks from mac80211 to the driver
  *
  * This structure contains various callbacks that the driver may
@@ -1674,6 +1688,26 @@ enum ieee80211_ampdu_mlme_action {
  *	of the bss parameters has changed when a call is made. The callback
  *	can sleep.
  *
+ * @tx_sync: Called before a frame is sent to an AP/GO. In the GO case, the
+ *	driver should sync with the GO's powersaving so the device doesn't
+ *	transmit the frame while the GO is asleep. In the regular AP case
+ *	it may be used by drivers for devices implementing other restrictions
+ *	on talking to APs, e.g. due to regulatory enforcement or just HW
+ *	restrictions.
+ *	This function is called for every authentication, association and
+ *	action frame separately since applications might attempt to auth
+ *	with multiple APs before chosing one to associate to. If it returns
+ *	an error, the corresponding authentication, association or frame
+ *	transmission is aborted and reported as having failed. It is always
+ *	called after tuning to the correct channel.
+ *	The callback might be called multiple times before @finish_tx_sync
+ *	(but @finish_tx_sync will be called once for each) but in practice
+ *	this is unlikely to happen. It can also refuse in that case if the
+ *	driver cannot handle that situation.
+ *	This callback can sleep.
+ * @finish_tx_sync: Called as a counterpart to @tx_sync, unless that returned
+ *	an error. This callback can sleep.
+ *
  * @prepare_multicast: Prepare for multicast filter configuration.
  *	This callback is optional, and its return value is passed
  *	to configure_filter(). This callback must be atomic.
@@ -1901,6 +1935,14 @@ struct ieee80211_ops {
 				 struct ieee80211_vif *vif,
 				 struct ieee80211_bss_conf *info,
 				 u32 changed);
+
+	int (*tx_sync)(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
+		       const u8 *bssid, enum ieee80211_tx_sync_type type);
+	void (*finish_tx_sync)(struct ieee80211_hw *hw,
+			       struct ieee80211_vif *vif,
+			       const u8 *bssid,
+			       enum ieee80211_tx_sync_type type);
+
 	u64 (*prepare_multicast)(struct ieee80211_hw *hw,
 				 struct netdev_hw_addr_list *mc_list);
 	void (*configure_filter)(struct ieee80211_hw *hw,