batman-adv: Receive fragmented packets and merge

Fragments arriving at their destination are buffered for later merge.
Merged packets are passed to the main receive function as had they never
been fragmented.

Fragments are forwarded without merging if the MTU of the outgoing
interface is smaller than the size of the merged packet.

Signed-off-by: Martin Hundebøll <martin@hundeboll.net>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>
diff --git a/net/batman-adv/routing.h b/net/batman-adv/routing.h
index efab583..55d637a 100644
--- a/net/batman-adv/routing.h
+++ b/net/batman-adv/routing.h
@@ -30,6 +30,8 @@
 			    struct batadv_hard_iface *recv_if);
 int batadv_recv_unicast_packet(struct sk_buff *skb,
 			       struct batadv_hard_iface *recv_if);
+int batadv_recv_frag_packet(struct sk_buff *skb,
+			    struct batadv_hard_iface *iface);
 int batadv_recv_bcast_packet(struct sk_buff *skb,
 			     struct batadv_hard_iface *recv_if);
 int batadv_recv_tt_query(struct sk_buff *skb,