As the kernel doc describes too the code is supposed to skip adding multicast TT entries if both the WANT_ALL_IPV4 and WANT_ALL_IPV6 flags are present.

Unfortunately, the current code even skips adding multicast TT entries if only either the WANT_ALL_IPV4 or WANT_ALL_IPV6 is present.

This could lead to IPv6 multicast packet loss if only an IGMP but not an MLD querier is present for instance or vice versa.

Fixes: 391b59cdb111 ("batman-adv: Add multicast optimization support for bridged setups") Signed-off-by: Linus Lüssing linus.luessing@c0d3.blue --- v3: Added "Fixes:" line v2: Fixed typo in last sentence: "non" -> "not"

net/batman-adv/multicast.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/batman-adv/multicast.c b/net/batman-adv/multicast.c index 6eaffe50..15a7b314 100644 --- a/net/batman-adv/multicast.c +++ b/net/batman-adv/multicast.c @@ -543,8 +543,8 @@ static bool batadv_mcast_mla_tvlv_update(struct batadv_priv *bat_priv) bat_priv->mcast.enabled = true; }

- return !(mcast_data.flags & - (BATADV_MCAST_WANT_ALL_IPV4 | BATADV_MCAST_WANT_ALL_IPV6)); + return !(mcast_data.flags & BATADV_MCAST_WANT_ALL_IPV4 && + mcast_data.flags & BATADV_MCAST_WANT_ALL_IPV6); }

/**