cfg80211: introduce capability for 4addr mode

It's very likely that not many devices will support
four-address mode in station or AP mode so introduce
capability bits for both modes, set them in mac80211
and check them when userspace tries to use the mode.
Also, keep track of 4addr in cfg80211 (wireless_dev)
and not in mac80211 any more. mac80211 can also be
improved for the VLAN case by not looking at the
4addr flag but maintaining the station pointer for
it correctly. However, keep track of use_4addr for
station mode in mac80211 to avoid all the derefs.

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

1 files changed, 11 insertions, 0 deletions

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index eca36abca8f..d1e05aeb0c0 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -1134,6 +1134,9 @@ struct cfg80211_ops {
  *	by default -- this flag will be set depending on the kernel's default
  *	on wiphy_new(), but can be changed by the driver if it has a good
  *	reason to override the default
+ * @WIPHY_FLAG_4ADDR_AP: supports 4addr mode even on AP (with a single station
+ *	on a VLAN interface)
+ * @WIPHY_FLAG_4ADDR_STATION: supports 4addr mode even as a station
  */
 enum wiphy_flags {
 	WIPHY_FLAG_CUSTOM_REGULATORY	= BIT(0),
@@ -1141,6 +1144,8 @@ enum wiphy_flags {
 	WIPHY_FLAG_DISABLE_BEACON_HINTS	= BIT(2),
 	WIPHY_FLAG_NETNS_OK		= BIT(3),
 	WIPHY_FLAG_PS_ON_BY_DEFAULT	= BIT(4),
+	WIPHY_FLAG_4ADDR_AP		= BIT(5),
+	WIPHY_FLAG_4ADDR_STATION	= BIT(6),
 };
 
 /**
@@ -1366,6 +1371,10 @@ struct cfg80211_cached_keys;
  * @ssid_len: (private) Used by the internal configuration code
  * @wext: (private) Used by the internal wireless extensions compat code
  * @wext_bssid: (private) Used by the internal wireless extensions compat code
+ * @use_4addr: indicates 4addr mode is used on this interface, must be
+ *	set by driver (if supported) on add_interface BEFORE registering the
+ *	netdev and may otherwise be used by driver read-only, will be update
+ *	by cfg80211 on change_interface
  */
 struct wireless_dev {
 	struct wiphy *wiphy;
@@ -1379,6 +1388,8 @@ struct wireless_dev {
 
 	struct work_struct cleanup_work;
 
+	bool use_4addr;
+
 	/* currently used for IBSS and SME - might be rearranged later */
 	u8 ssid[IEEE80211_MAX_SSID_LEN];
 	u8 ssid_len;