From a9765e4ce5f9b2d375caf6710a1e5f7e11a60c98 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Linus=20L=C3=BCssing?= Date: Thu, 30 Oct 2014 05:40:46 +0100 Subject: [PATCH] batman-adv: fix counter for multicast supporting nodes MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 1b8d573fd585ce83800e8eff81d6198f88215c7e ("batman-adv: Announce new capability via multicast TVLV") Reported-by: Tobias Hachmer Signed-off-by: Linus Lüssing Signed-off-by: Marek Lindner Signed-off-by: Antonio Quartulli --- net/batman-adv/multicast.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/net/batman-adv/multicast.c b/net/batman-adv/multicast.c index ab6bb2af1d45d..d3503fbfec939 100644 --- a/net/batman-adv/multicast.c +++ b/net/batman-adv/multicast.c @@ -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; } -- 2.39.5