From 8fad9c39f31f9ed7bf3526c43a4537b2fcf1a5d5 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Linus=20L=C3=BCssing?= Date: Wed, 4 Sep 2013 02:13:38 +0200 Subject: [PATCH] bridge: prevent flooding IPv6 packets that do not have a listener MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Currently if there is no listener for a certain group then IPv6 packets for that group are flooded on all ports, even though there might be no host and router interested in it on a port. With this commit they are only forwarded to ports with a multicast router. Just like commit bd4265fe36 ("bridge: Only flood unregistered groups to routers") did for IPv4, let's do the same for IPv6 with the same reasoning. Signed-off-by: Linus Lüssing Signed-off-by: David S. Miller --- net/bridge/br_multicast.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c index 4accd0de6e8..5388955b2a3 100644 --- a/net/bridge/br_multicast.c +++ b/net/bridge/br_multicast.c @@ -1491,8 +1491,14 @@ static int br_multicast_ipv6_rcv(struct net_bridge *br, * - MLD has always Router Alert hop-by-hop option * - But we do not support jumbrograms. */ - if (ip6h->version != 6 || - ip6h->nexthdr != IPPROTO_HOPOPTS || + if (ip6h->version != 6) + return 0; + + /* Prevent flooding this packet if there is no listener present */ + if (ipv6_is_transient_multicast(&ip6h->daddr)) + BR_INPUT_SKB_CB(skb)->mrouters_only = 1; + + if (ip6h->nexthdr != IPPROTO_HOPOPTS || ip6h->payload_len == 0) return 0; -- 2.41.0