vxlan: ecmp support for mac fdb entries
Todays vxlan mac fdb entries can point to multiple remote ips (rdsts) with the sole purpose of replicating broadcast-multicast and unknown unicast packets to those remote ips. E-VPN multihoming [1,2,3] requires bridged vxlan traffic to be load balanced to remote switches (vteps) belonging to the same multi-homed ethernet segment (E-VPN multihoming is analogous to multi-homed LAG implementations, but with the inter-switch peerlink replaced with a vxlan tunnel). In other words it needs support for mac ecmp. Furthermore, for faster convergence, E-VPN multihoming needs the ability to update fdb ecmp nexthops independent of the fdb entries. New route nexthop API is perfect for this usecase. This patch extends the vxlan fdb code to take a nexthop id pointing to an ecmp nexthop group. Changes include: - New NDA_NH_ID attribute for fdbs - Use the newly added fdb nexthop groups - makes vxlan rdsts and nexthop handling code mutually exclusive - since this is a new use-case and the requirement is for ecmp nexthop groups, the fdb add and update path checks that the nexthop is really an ecmp nexthop group. This check can be relaxed in the future, if we want to introduce replication fdb nexthop groups and allow its use in lieu of current rdst lists. - fdb update requests with nexthop id's only allowed for existing fdb's that have nexthop id's - learning will not override an existing fdb entry with nexthop group - I have wrapped the switchdev offload code around the presence of rdst [1] E-VPN RFC https://tools.ietf.org/html/rfc7432 [2] E-VPN with vxlan https://tools.ietf.org/html/rfc8365 [3] http://vger.kernel.org/lpc_net2018_talks/scaling_bridge_fdb_database_slidesV3.pdf Includes a null check fix in vxlan_xmit from Nikolay v2 - Fixed build issue: Reported-by:kbuild test robot <lkp@intel.com> Signed-off-by:
Roopa Prabhu <roopa@cumulusnetworks.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
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