On 15/03/2023 15:11, Ido Schimmel wrote:
> Integrate MDB support into the Tx path of the VXLAN driver, allowing it
> to selectively forward IP multicast traffic according to the matched MDB
> entry.
>
> If MDB entries are configured (i.e., 'VXLAN_F_MDB' is set) and the
> packet is an IP multicast packet, perform up to three different lookups
> according to the following priority:
>
> 1. For an (S, G) entry, using {Source VNI, Source IP, Destination IP}.
> 2. For a (*, G) entry, using {Source VNI, Destination IP}.
> 3. For the catchall MDB entry (0.0.0.0 or ::), using the source VNI.
>
> The catchall MDB entry is similar to the catchall FDB entry
> (00:00:00:00:00:00) that is currently used to transmit BUM (broadcast,
> unknown unicast and multicast) traffic. However, unlike the catchall FDB
> entry, this entry is only used to transmit unregistered IP multicast
> traffic that is not link-local. Therefore, when configured, the catchall
> FDB entry will only transmit BULL (broadcast, unknown unicast,
> link-local multicast) traffic.
>
> The catchall MDB entry is useful in deployments where inter-subnet
> multicast forwarding is used and not all the VTEPs in a tenant domain
> are members in all the broadcast domains. In such deployments it is
> 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].
>
> If the packet did not match an MDB entry (or if the packet is not an IP
> multicast packet), return it to the Tx path, allowing it to be forwarded
> according to the FDB.
>
> If the packet did match an MDB entry, forward it to the associated
> remote VTEPs. However, if the entry is a (*, G) entry and the associated
> remote is in INCLUDE mode, then skip over it as the source IP is not in
> its source list (otherwise the packet would have matched on an (S, G)
> entry). Similarly, if the associated remote is marked as BLOCKED (can
> only be set on (S, G) entries), then skip over it as well as the remote
> is in EXCLUDE mode and the source IP is in its source list.
>
> [1] https://datatracker.ietf.org/doc/html/draft-ietf-bess-evpn-irb-mcast#section-2.6
>
> Signed-off-by: Ido Schimmel <idosch@xxxxxxxxxx>
> ---
>
> Notes:
> v2:
> * Use htons() in 'case' instead of ntohs() in 'switch'.
>
> drivers/net/vxlan/vxlan_core.c | 15 ++++
> drivers/net/vxlan/vxlan_mdb.c | 114 ++++++++++++++++++++++++++++++
> drivers/net/vxlan/vxlan_private.h | 6 ++
> 3 files changed, 135 insertions(+)
>
Reviewed-by: Nikolay Aleksandrov <razor@xxxxxxxxxxxxx>
