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 <linus.luessing@web.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index 4accd0d..5388955 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -1491,8 +1491,14 @@
* - 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;