batman-adv: implement AP-isolation on the sender side

If a node has to send a packet issued by a WIFI client to another WIFI client,
the packet is dropped.

Signed-off-by: Antonio Quartulli <ordex@autistici.org>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
diff --git a/net/batman-adv/unicast.c b/net/batman-adv/unicast.c
index 32b125f..07d1c1d 100644
--- a/net/batman-adv/unicast.c
+++ b/net/batman-adv/unicast.c
@@ -299,8 +299,10 @@
 			goto find_router;
 	}
 
-	/* check for tt host - increases orig_node refcount */
-	orig_node = transtable_search(bat_priv, ethhdr->h_dest);
+	/* check for tt host - increases orig_node refcount.
+	 * returns NULL in case of AP isolation */
+	orig_node = transtable_search(bat_priv, ethhdr->h_source,
+				      ethhdr->h_dest);
 
 find_router:
 	/**