On Tue, Feb 19, 2019 at 09:57:16AM +0100, Linus Lüssing wrote: > On Mon, Feb 18, 2019 at 02:21:07PM +0200, Nikolay Aleksandrov wrote: > > This is v2 of the RFC patch which aims to forward packets to known > > mdsts' ports only (the no querier case). After v1 I've kept > > the previous behaviour when it comes to unregistered traffic or when > > a querier is present. All of this is of course only with snooping > > enabled. So with this patch the following changes should occur: > > - No querier: forward known mdst traffic to its registered ports, > > no change about unknown mcast (flood) > > - Querier present: no change > > > > The reason to do this is simple - we want to respect the user's mdb > > configuration in both cases, that is if the user adds static mdb entries > > manually then we should use that information about forwarding traffic. > > > > What do you think ? > > > > * Notes > > Traffic that is currently marked as mrouters_only: > > - IPv4: non-local mcast traffic, igmp reports > > - IPv6: non-all-nodes-dst mcast traffic, mldv1 reports > > > > Simple use case: > > $ echo 1 > /sys/class/net/bridge/bridge/multicast_snooping > > $ bridge mdb add dev bridge port swp1 grp 239.0.0.1 > > - without a querier currently traffic for 239.0.0.1 will still be flooded, > > with this change it will be forwarded only to swp1 > > There is still the issue with unsolicited reports adding mdst > entries here, too. Leading to unwanted packet loss and connectivity issues. Or in other words, an unsolicited report will turn a previously unregistered multicast group into a registered one. However in the absence of a querier the knowledge about this newly registered multicast group will be incomplete. And therefore still needs to be flooded to avoid packet loss.
