From: Linus Lüssing Date: Wed, 4 Sep 2013 00:13:38 +0000 (+0200) Subject: bridge: prevent flooding IPv6 packets that do not have a listener X-Git-Tag: v3.12-rc1~132^2~15 X-Git-Url: http://git.cascardo.eti.br/?a=commitdiff_plain;h=8fad9c39f31f9ed7bf3526c43a4537b2fcf1a5d5;p=cascardo%2Flinux.git bridge: prevent flooding IPv6 packets that do not have a listener 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 --- diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c index 4accd0de6e8e..5388955b2a3c 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;