batman-adv: Add bonding mesh genl configuration

The mesh interface can use multiple slave/hard-interface ports at the same
time to transport the traffic to other nodes.

The BATADV_CMD_SET_MESH/BATADV_CMD_GET_MESH commands allow to set/get the
configuration of this feature using the BATADV_ATTR_BONDING_ENABLED
attribute. Setting the u8 to zero will disable this feature and setting it
to something else is enabling this feature.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

include/uapi/linux/batman_adv.h

@@ -375,6 +375,12 @@ enum batadv_nl_attrs {
 	 */
 	BATADV_ATTR_ISOLATION_MASK,
 
+	/**
+	 * @BATADV_ATTR_BONDING_ENABLED: whether the data traffic going through
+	 *  the mesh will be sent using multiple interfaces at the same time.
+	 */
+	BATADV_ATTR_BONDING_ENABLED,
+
 	/* add attributes above here, update the policy in netlink.c */
 
 	/**