batman-adv: network coding - detect coding nodes and remove these after timeout

To use network coding efficiently, a relay must know when neighbor nodes
are likely to have enough information to be able to decode a network
coded packet. This is detected by using OGMs from batman-adv to discover
when one neighbor is in range of another neighbor. The relay check the
TLL to detect when an OGM is forwarded from one neighbor by another
neighbor, and thereby knows that the two neighbors are in range and thus
overhear packets sent by each other.

This information is saved in the orig_node struct to be used when
searching for coding opportunities. Two lists are added to the
orig_node struct: One for neighbors that can hear the orig_node
(outgoing nc_nodes) and one for neighbors that the orig_node can hear
(incoming nc_nodes).

Information about nc_nodes is kept for 10 seconds and is available
through debugfs in batman_adv/nc_nodes to use when debugging network
coding.

Signed-off-by: Martin Hundebøll <martin@hundeboll.net>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
Signed-off-by: Antonio Quartulli <ordex@autistici.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/net/batman-adv/bat_iv_ogm.c b/net/batman-adv/bat_iv_ogm.c
index a5bb0a769eb9..071f288b77a8 100644
--- a/net/batman-adv/bat_iv_ogm.c
+++ b/net/batman-adv/bat_iv_ogm.c
@@ -27,6 +27,7 @@
 #include "hard-interface.h"
 #include "send.h"
 #include "bat_algo.h"
+#include "network-coding.h"
 
 static struct batadv_neigh_node *
 batadv_iv_ogm_neigh_new(struct batadv_hard_iface *hard_iface,
@@ -1185,6 +1186,10 @@ static void batadv_iv_ogm_process(const struct ethhdr *ethhdr,
         if (!orig_neigh_node)
                 goto out;
 
+        /* Update nc_nodes of the originator */
+        batadv_nc_update_nc_node(bat_priv, orig_node, orig_neigh_node,
+                                 batadv_ogm_packet, is_single_hop_neigh);
+
         orig_neigh_router = batadv_orig_node_get_router(orig_neigh_node);
 
         /* drop packet if sender is not a direct neighbor and if we