batman-adv: Distributed ARP Table - add ARP parsing functions

ARP messages are now parsed to make it possible to trigger special actions
depending on their types (snooping).

Signed-off-by: Antonio Quartulli <ordex@autistici.org>
diff --git a/net/batman-adv/packet.h b/net/batman-adv/packet.h
index 0f8dcf3..df548ed 100644
--- a/net/batman-adv/packet.h
+++ b/net/batman-adv/packet.h
@@ -37,9 +37,15 @@
 /**
  * enum batadv_subtype - packet subtype for unicast4addr
  * @BATADV_P_DATA: user payload
+ * @BATADV_P_DAT_DHT_GET: DHT request message
+ * @BATADV_P_DAT_DHT_PUT: DHT store message
+ * @BATADV_P_DAT_CACHE_REPLY: ARP reply generated by DAT
  */
 enum batadv_subtype {
-	BATADV_P_DATA		= 0x01,
+	BATADV_P_DATA			= 0x01,
+	BATADV_P_DAT_DHT_GET		= 0x02,
+	BATADV_P_DAT_DHT_PUT		= 0x03,
+	BATADV_P_DAT_CACHE_REPLY	= 0x04,
 };
 
 /* this file is included by batctl which needs these defines */