nl80211: prepare for non-netdev wireless devs

In order to support a P2P device abstraction and
Bluetooth high-speed AMPs, we need to have a way
to identify virtual interfaces that don't have a
netdev associated.

Do this by adding a NL80211_ATTR_WDEV attribute
to identify a wdev which may or may not also be
a netdev.

To simplify things, use a 64-bit value with the
high 32 bits being the wiphy index for this new
wdev identifier in the nl80211 API.

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

2 files changed, 21 insertions, 6 deletions

diff --git a/include/linux/nl80211.h b/include/linux/nl80211.h
index db961a59247..e791487ead3 100644
--- a/include/linux/nl80211.h
+++ b/include/linux/nl80211.h
@@ -771,6 +771,9 @@ enum nl80211_commands {
  * @NL80211_ATTR_IFNAME: network interface name
  * @NL80211_ATTR_IFTYPE: type of virtual interface, see &enum nl80211_iftype
  *
+ * @NL80211_ATTR_WDEV: wireless device identifier, used for pseudo-devices
+ *	that don't have a netdev (u64)
+ *
  * @NL80211_ATTR_MAC: MAC address (various uses)
  *
  * @NL80211_ATTR_KEY_DATA: (temporal) key data; for TKIP this consists of
@@ -1493,6 +1496,8 @@ enum nl80211_attrs {
 
 	NL80211_ATTR_BG_SCAN_PERIOD,
 
+	NL80211_ATTR_WDEV,
+
 	/* 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 51f67a9003a..a14e6a40668 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -2341,17 +2341,25 @@ struct cfg80211_internal_bss;
 struct cfg80211_cached_keys;
 
 /**
- * struct wireless_dev - wireless per-netdev state
+ * struct wireless_dev - wireless device state
  *
- * This structure must be allocated by the driver/stack
- * that uses the ieee80211_ptr field in struct net_device
- * (this is intentional so it can be allocated along with
- * the netdev.)
+ * For netdevs, this structure must be allocated by the driver
+ * that uses the ieee80211_ptr field in struct net_device (this
+ * is intentional so it can be allocated along with the netdev.)
+ * It need not be registered then as netdev registration will
+ * be intercepted by cfg80211 to see the new wireless device.
+ *
+ * For non-netdev uses, it must also be allocated by the driver
+ * in response to the cfg80211 callbacks that require it, as
+ * there's no netdev registration in that case it may not be
+ * allocated outside of callback operations that return it.
  *
  * @wiphy: pointer to hardware description
  * @iftype: interface type
  * @list: (private) Used to collect the interfaces
- * @netdev: (private) Used to reference back to the netdev
+ * @netdev: (private) Used to reference back to the netdev, may be %NULL
+ * @identifier: (private) Identifier used in nl80211 to identify this
+ *	wireless device if it has no netdev
  * @current_bss: (private) Used by the internal configuration code
  * @channel: (private) Used by the internal configuration code to track
  *	the user-set AP, monitor and WDS channel
@@ -2383,6 +2391,8 @@ struct wireless_dev {
 	struct list_head list;
 	struct net_device *netdev;
 
+	u32 identifier;
+
 	struct list_head mgmt_registrations;
 	spinlock_t mgmt_registrations_lock;