mac802154: monitor device support

Support for monitor device intended to capture all the network activity.
This interface could be used by networks sniffers and is already
supported by WireShark. That's a good test point to check that basic
MAC support works.

Signed-off-by: Alexander Smirnov <alex.bluesman.smirnov@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/nl802154.h

@@ -129,6 +129,20 @@ enum {
 
 enum {
 	__IEEE802154_DEV_INVALID = -1,
+
+	 /* TODO:
+	 * Nowadays three device types supported by this stack at linux-zigbee
+	 * project: WPAN = 0, MONITOR = 1 and SMAC = 2.
+	 *
+	 * Since this stack implementation exists many years, it's definitely
+	 * bad idea to change the assigned values due to they are already used
+	 * by third-party userspace software like: iz-tools, wireshark...
+	 *
+	 * Currently only monitor device is added and initialized by '1' for
+	 * compatibility.
+	 */
+	IEEE802154_DEV_MONITOR = 1,
+
 	__IEEE802154_DEV_MAX,
 };