On 13/03/2023 16:53, Ido Schimmel wrote: > In the upcoming VXLAN MDB implementation, the 0.0.0.0 and :: MDB entries > will act as catchall entries for unregistered IP multicast traffic in a > similar fashion to the 00:00:00:00:00:00 VXLAN FDB entry that is used to > transmit BUM traffic. > > In deployments where inter-subnet multicast forwarding is used, not all > the VTEPs in a tenant domain are members in all the broadcast domains. > It is therefore advantageous to transmit BULL (broadcast, unknown > unicast and link-local multicast) and unregistered IP multicast traffic > on different tunnels. If the same tunnel was used, a VTEP only > interested in IP multicast traffic would also pull all the BULL traffic > and drop it as it is not a member in the originating broadcast domain > [1]. > > Prepare for this change by allowing the 0.0.0.0 group address in the > common rtnetlink MDB code and forbid it in the bridge driver. A similar > change is not needed for IPv6 because the common code only validates > that the group address is not the all-nodes address. > > [1] https://datatracker.ietf.org/doc/html/draft-ietf-bess-evpn-irb-mcast#section-2.6 > > Signed-off-by: Ido Schimmel <idosch@xxxxxxxxxx> > --- > net/bridge/br_mdb.c | 6 ++++++ > net/core/rtnetlink.c | 5 +++-- > 2 files changed, 9 insertions(+), 2 deletions(-) > Reviewed-by: Nikolay Aleksandrov <razor@xxxxxxxxxxxxx>
