batman-adv: Simple (re)broadcast avoidance

With this patch, (re)broadcasting on a specific interfaces is avoided:

* No neighbor: There is no need to broadcast on an interface if there
  is no node behind it.

* Single neighbor is source: If there is just one neighbor on an
  interface and if this neighbor is the one we actually got this
  broadcast packet from, then we do not need to echo it back.

* Single neighbor is originator: If there is just one neighbor on
  an interface and if this neighbor is the originator of this
  broadcast packet, then we do not need to echo it back.

Goodies for BATMAN V:

("Upgrade your BATMAN IV network to V now to get these for free!")

Thanks to the split of OGMv1 into two packet types, OGMv2 and ELP
that is, we can now apply the same optimizations stated above to OGMv2
packets, too.

Furthermore, with BATMAN V, rebroadcasts can be reduced in certain
multi interface cases, too, where BATMAN IV cannot. This is thanks to
the removal of the "secondary interface originator" concept in BATMAN V.

Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

1 files changed, 9 insertions, 4 deletions

diff --git a/net/batman-adv/originator.c b/net/batman-adv/originator.c
index 518b1ed87b64..ad26559160fa 100644
--- a/net/batman-adv/originator.c
+++ b/net/batman-adv/originator.c
@@ -512,12 +512,14 @@ batadv_neigh_node_get(const struct batadv_orig_node *orig_node,
  * batadv_hardif_neigh_create - create a hardif neighbour node
  * @hard_iface: the interface this neighbour is connected to
  * @neigh_addr: the interface address of the neighbour to retrieve
+ * @orig_node: originator object representing the neighbour
  *
  * Return: the hardif neighbour node if found or created or NULL otherwise.
  */
 static struct batadv_hardif_neigh_node *
 batadv_hardif_neigh_create(struct batadv_hard_iface *hard_iface,
-			   const u8 *neigh_addr)
+			   const u8 *neigh_addr,
+			   struct batadv_orig_node *orig_node)
 {
 	struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 	struct batadv_hardif_neigh_node *hardif_neigh;
@@ -536,6 +538,7 @@ batadv_hardif_neigh_create(struct batadv_hard_iface *hard_iface,
 	kref_get(&hard_iface->refcount);
 	INIT_HLIST_NODE(&hardif_neigh->list);
 	ether_addr_copy(hardif_neigh->addr, neigh_addr);
+	ether_addr_copy(hardif_neigh->orig, orig_node->orig);
 	hardif_neigh->if_incoming = hard_iface;
 	hardif_neigh->last_seen = jiffies;
 
@@ -556,12 +559,14 @@ out:
  *  node
  * @hard_iface: the interface this neighbour is connected to
  * @neigh_addr: the interface address of the neighbour to retrieve
+ * @orig_node: originator object representing the neighbour
  *
  * Return: the hardif neighbour node if found or created or NULL otherwise.
  */
 static struct batadv_hardif_neigh_node *
 batadv_hardif_neigh_get_or_create(struct batadv_hard_iface *hard_iface,
-				  const u8 *neigh_addr)
+				  const u8 *neigh_addr,
+				  struct batadv_orig_node *orig_node)
 {
 	struct batadv_hardif_neigh_node *hardif_neigh;
 
@@ -570,7 +575,7 @@ batadv_hardif_neigh_get_or_create(struct batadv_hard_iface *hard_iface,
 	if (hardif_neigh)
 		return hardif_neigh;
 
-	return batadv_hardif_neigh_create(hard_iface, neigh_addr);
+	return batadv_hardif_neigh_create(hard_iface, neigh_addr, orig_node);
 }
 
 /**
@@ -630,7 +635,7 @@ batadv_neigh_node_create(struct batadv_orig_node *orig_node,
 		goto out;
 
 	hardif_neigh = batadv_hardif_neigh_get_or_create(hard_iface,
-							 neigh_addr);
+							 neigh_addr, orig_node);
 	if (!hardif_neigh)
 		goto out;