batman-adv: Fragment and send skbs larger than mtu

Non-broadcast packets larger than MTU are fragmented and sent with
an encapsulating header. Up to 16 fragments are supported, which are
sent in reverse order on the wire to allow minimal memory copying when
creating fragments.

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>

net/batman-adv/fragmentation.h

@@ -27,6 +27,9 @@ bool batadv_frag_skb_fwd(struct sk_buff *skb,
 			 struct batadv_orig_node *orig_node_src);
 bool batadv_frag_skb_buffer(struct sk_buff **skb,
 			    struct batadv_orig_node *orig_node);
+bool batadv_frag_send_packet(struct sk_buff *skb,
+			     struct batadv_orig_node *orig_node,
+			     struct batadv_neigh_node *neigh_node);
 
 /**
  * batadv_frag_check_entry - check if a list of fragments has timed out