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>

1 files changed, 17 insertions, 4 deletions

diff --git a/net/batman-adv/send.c b/net/batman-adv/send.c
index b8356ec067bf..1a1aa59d78ee 100644
--- a/net/batman-adv/send.c
+++ b/net/batman-adv/send.c
@@ -28,8 +28,7 @@
 #include "gateway_client.h"
 #include "originator.h"
 #include "network-coding.h"
-
-#include <linux/if_ether.h>
+#include "fragmentation.h"
 
 static void batadv_send_outstanding_bcast_packet(struct work_struct *work);
 
@@ -109,7 +108,19 @@ int batadv_send_skb_to_orig(struct sk_buff *skb,
 	/* batadv_find_router() increases neigh_nodes refcount if found. */
 	neigh_node = batadv_find_router(bat_priv, orig_node, recv_if);
 	if (!neigh_node)
-		return ret;
+		goto out;
+
+	/* Check if the skb is too large to send in one piece and fragment
+	 * it if needed.
+	 */
+	if (atomic_read(&bat_priv->fragmentation) &&
+	    skb->len > neigh_node->if_incoming->net_dev->mtu) {
+		/* Fragment and send packet. */
+		if (batadv_frag_send_packet(skb, orig_node, neigh_node))
+			ret = NET_XMIT_SUCCESS;
+
+		goto out;
+	}
 
 	/* try to network code the packet, if it is received on an interface
 	 * (i.e. being forwarded). If the packet originates from this node or if
@@ -123,7 +134,9 @@ int batadv_send_skb_to_orig(struct sk_buff *skb,
 		ret = NET_XMIT_SUCCESS;
 	}
 
-	batadv_neigh_node_free_ref(neigh_node);
+out:
+	if (neigh_node)
+		batadv_neigh_node_free_ref(neigh_node);
 
 	return ret;
 }