batman-adv: fix counter for multicast supporting nodes

A miscounting of nodes having multicast optimizations enabled can lead
to multicast packet loss in the following scenario:

If the first OGM a node receives from another one has no multicast
optimizations support (no multicast tvlv) then we are missing to
increase the counter. This potentially leads to the wrong assumption
that we could safely use multicast optimizations.

Fixings this by increasing the counter if the initial OGM has the
multicast TVLV unset, too.

Introduced by 60432d756c
("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>
This commit is contained in:
Linus Lüssing 2014-10-30 05:40:46 +01:00 committed by Antonio Quartulli
parent f44d54077a
commit e8829f007e

View File

@ -685,11 +685,13 @@ static void batadv_mcast_tvlv_ogm_handler_v1(struct batadv_priv *bat_priv,
if (orig_initialized)
atomic_dec(&bat_priv->mcast.num_disabled);
orig->capabilities |= BATADV_ORIG_CAPA_HAS_MCAST;
/* If mcast support is being switched off increase the disabled
* mcast node counter.
/* If mcast support is being switched off or if this is an initial
* OGM without mcast support then increase the disabled mcast
* node counter.
*/
} else if (!orig_mcast_enabled &&
orig->capabilities & BATADV_ORIG_CAPA_HAS_MCAST) {
(orig->capabilities & BATADV_ORIG_CAPA_HAS_MCAST ||
!orig_initialized)) {
atomic_inc(&bat_priv->mcast.num_disabled);
orig->capabilities &= ~BATADV_ORIG_CAPA_HAS_MCAST;
}