batman-adv: fix multicast counter when purging originators

When purging an orig_node we should only decrease counter tracking the
number of nodes without multicast optimizations support if it was
increased through this orig_node before.

A not yet quite initialized orig_node (meaning it did not have its turn
in the mcast-tvlv handler so far) which gets purged would not adhere to
this and will lead to a counter imbalance.

Fixing this by adding a check whether the orig_node is mcast-initalized
before decreasing the counter in the mcast-orig_node-purging routine.

Introduced by 60432d756cf06e597ef9da511402dd059b112447
("batman-adv: Announce new capability via multicast TVLV")

Reported-by: Tobias Hachmer <tobias@hachmer.de>
Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>

diff --git a/net/batman-adv/multicast.c b/net/batman-adv/multicast.c
index d3503fbfec93962e4168033bff6e5f529fd55f95..b24e4bb64fb5fd51c813df7e5801b98d27caf959 100644 (file)
--- a/net/batman-adv/multicast.c
+++ b/net/batman-adv/multicast.c
@@ -740,7 +740,8 @@ void batadv_mcast_purge_orig(struct batadv_orig_node *orig)
 {
        struct batadv_priv *bat_priv = orig->bat_priv;
 
-       if (!(orig->capabilities & BATADV_ORIG_CAPA_HAS_MCAST))
+       if (!(orig->capabilities & BATADV_ORIG_CAPA_HAS_MCAST) &&
+           orig->capa_initialized & BATADV_ORIG_CAPA_HAS_MCAST)
                atomic_dec(&bat_priv->mcast.num_disabled);
 
        batadv_mcast_want_unsnoop_update(bat_priv, orig, BATADV_NO_FLAGS);