batman-adv: don't add TEMP clients belonging to other backbone nodes

The "early client detection" mechanism must not add clients belonging
to other backbone nodes. Such clients must be reached by directly
using the LAN instead of the mesh.

This was introduced by 30cfd02b60
("batman-adv: detect not yet announced clients")

Reported-by: Glen Page <glen.page@thet.net>
Signed-off-by: Antonio Quartulli <ordex@autistici.org>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>

net/batman-adv/translation-table.c

@@ -2456,6 +2456,13 @@ bool batadv_tt_add_temporary_global_entry(struct batadv_priv *bat_priv,
 {
 	bool ret = false;
 
+	/* if the originator is a backbone node (meaning it belongs to the same
+	 * LAN of this node) the temporary client must not be added because to
+	 * reach such destination the node must use the LAN instead of the mesh
+	 */
+	if (batadv_bla_is_backbone_gw_orig(bat_priv, orig_node->orig))
+		goto out;
+
 	if (!batadv_tt_global_add(bat_priv, orig_node, addr,
 				  BATADV_TT_CLIENT_TEMP,
 				  atomic_read(&orig_node->last_ttvn)))