cfg80211: add P2P Device abstraction

In order to support using a different MAC address
for the P2P Device address we must first have a
P2P Device abstraction that can be assigned a MAC
address.

This abstraction will also be useful to support
offloading P2P operations to the device, e.g.
periodic listen for discoverability.

Currently, the driver is responsible for assigning
a MAC address to the P2P Device, but this could be
changed by allowing a MAC address to be given to
the NEW_INTERFACE command.

As it has no associated netdev, a P2P Device can
only be identified by its wdev identifier but the
previous patches allowed using the wdev identifier
in various APIs, e.g. remain-on-channel.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/net/cfg80211.h

@@ -1437,7 +1437,8 @@ struct cfg80211_gtk_rekey_data {
  * @add_virtual_intf: create a new virtual interface with the given name,
  *	must set the struct wireless_dev's iftype. Beware: You must create
  *	the new netdev in the wiphy's network namespace! Returns the struct
- *	wireless_dev, or an ERR_PTR.
+ *	wireless_dev, or an ERR_PTR. For P2P device wdevs, the driver must
+ *	also set the address member in the wdev.
  *
  * @del_virtual_intf: remove the virtual interface
  *
@@ -1616,6 +1617,9 @@ struct cfg80211_gtk_rekey_data {
  * @get_channel: Get the current operating channel for the virtual interface.
  *	For monitor interfaces, it should return %NULL unless there's a single
  *	current monitoring channel.
+ *
+ * @start_p2p_device: Start the given P2P device.
+ * @stop_p2p_device: Stop the given P2P device.
  */
 struct cfg80211_ops {
 	int	(*suspend)(struct wiphy *wiphy, struct cfg80211_wowlan *wow);
@@ -1832,6 +1836,11 @@ struct cfg80211_ops {
 		(*get_channel)(struct wiphy *wiphy,
 			       struct wireless_dev *wdev,
 			       enum nl80211_channel_type *type);
+
+	int	(*start_p2p_device)(struct wiphy *wiphy,
+				    struct wireless_dev *wdev);
+	void	(*stop_p2p_device)(struct wiphy *wiphy,
+				   struct wireless_dev *wdev);
 };
 
 /*
@@ -2395,6 +2404,8 @@ struct cfg80211_cached_keys;
  * @cleanup_work: work struct used for cleanup that can't be done directly
  * @beacon_interval: beacon interval used on this device for transmitting
  *	beacons, 0 when not valid
+ * @address: The address for this device, valid only if @netdev is %NULL
+ * @p2p_started: true if this is a P2P Device that has been started
  */
 struct wireless_dev {
 	struct wiphy *wiphy;
@@ -2413,7 +2424,9 @@ struct wireless_dev {
 
 	struct work_struct cleanup_work;
 
-	bool use_4addr;
+	bool use_4addr, p2p_started;
+
+	u8 address[ETH_ALEN] __aligned(sizeof(u16));
 
 	/* currently used for IBSS and SME - might be rearranged later */
 	u8 ssid[IEEE80211_MAX_SSID_LEN];
@@ -2461,6 +2474,13 @@ struct wireless_dev {
 #endif
 };
 
+static inline u8 *wdev_address(struct wireless_dev *wdev)
+{
+	if (wdev->netdev)
+		return wdev->netdev->dev_addr;
+	return wdev->address;
+}
+
 /**
  * wdev_priv - return wiphy priv from wireless_dev
  *
@@ -3528,6 +3548,22 @@ void cfg80211_ch_switch_notify(struct net_device *dev, int freq,
  */
 u32 cfg80211_calculate_bitrate(struct rate_info *rate);
 
+/**
+ * cfg80211_unregister_wdev - remove the given wdev
+ * @wdev: struct wireless_dev to remove
+ *
+ * Call this function only for wdevs that have no netdev assigned,
+ * e.g. P2P Devices. It removes the device from the list so that
+ * it can no longer be used. It is necessary to call this function
+ * even when cfg80211 requests the removal of the interface by
+ * calling the del_virtual_intf() callback. The function must also
+ * be called when the driver wishes to unregister the wdev, e.g.
+ * when the device is unbound from the driver.
+ *
+ * Requires the RTNL to be held.
+ */
+void cfg80211_unregister_wdev(struct wireless_dev *wdev);
+
 /* Logging, debugging and troubleshooting/diagnostic helpers. */
 
 /* wiphy_printk helpers, similar to dev_printk */