cfg80211: allow drivers to support random MAC addresses for scan

Add the necessary feature flags and a scan flag to support using
random MAC addresses for scan while unassociated.

The configuration for this supports an arbitrary MAC address
value and mask, so that any kind of configuration (e.g. fixed
OUI or full 46-bit random) can be requested. Full 46-bit random
is the default when no other configuration is passed.

Also add a small helper function to use the addr/mask correctly.

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

1 files changed, 25 insertions, 0 deletions

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 05aae22e92a5..bb748c4da5af 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -1437,6 +1437,10 @@ struct cfg80211_ssid {
  * @aborted: (internal) scan request was notified as aborted
  * @notified: (internal) scan request was notified as done or aborted
  * @no_cck: used to send probe requests at non CCK rate in 2GHz band
+ * @mac_addr: MAC address used with randomisation
+ * @mac_addr_mask: MAC address mask used with randomisation, bits that
+ *	are 0 in the mask should be randomised, bits that are 1 should
+ *	be taken from the @mac_addr
  */
 struct cfg80211_scan_request {
 	struct cfg80211_ssid *ssids;
@@ -1451,6 +1455,9 @@ struct cfg80211_scan_request {
 
 	struct wireless_dev *wdev;
 
+	u8 mac_addr[ETH_ALEN] __aligned(2);
+	u8 mac_addr_mask[ETH_ALEN] __aligned(2);
+
 	/* internal */
 	struct wiphy *wiphy;
 	unsigned long scan_start;
@@ -1461,6 +1468,17 @@ struct cfg80211_scan_request {
 	struct ieee80211_channel *channels[0];
 };
 
+static inline void get_random_mask_addr(u8 *buf, const u8 *addr, const u8 *mask)
+{
+	int i;
+
+	get_random_bytes(buf, ETH_ALEN);
+	for (i = 0; i < ETH_ALEN; i++) {
+		buf[i] &= ~mask[i];
+		buf[i] |= addr[i] & mask[i];
+	}
+}
+
 /**
  * struct cfg80211_match_set - sets of attributes to match
  *
@@ -1494,6 +1512,10 @@ struct cfg80211_match_set {
  * @channels: channels to scan
  * @min_rssi_thold: for drivers only supporting a single threshold, this
  *	contains the minimum over all matchsets
+ * @mac_addr: MAC address used with randomisation
+ * @mac_addr_mask: MAC address mask used with randomisation, bits that
+ *	are 0 in the mask should be randomised, bits that are 1 should
+ *	be taken from the @mac_addr
  */
 struct cfg80211_sched_scan_request {
 	struct cfg80211_ssid *ssids;
@@ -1508,6 +1530,9 @@ struct cfg80211_sched_scan_request {
 	int n_match_sets;
 	s32 min_rssi_thold;
 
+	u8 mac_addr[ETH_ALEN] __aligned(2);
+	u8 mac_addr_mask[ETH_ALEN] __aligned(2);
+
 	/* internal */
 	struct wiphy *wiphy;
 	struct net_device *dev;