8111d1e9a8
The TAP interface does copy forward the host MTU based on the VPP interface's L3 MTU, but it should also ensure that the VPP tap interface has an MTU that is greater-or-equal to those. Considering users can set the interfaces at runtime (set interface mtu packet ...) ensure that the tap MTU is large enough. Ideally, a callback updates the MTU to the same value as the L3 MTU of the VPP interface, or the L3 MTU of the host interface, if either of those change. For now, it's a safe bet to take jumbo 9216.
This code was taken from VPP's src/plugins/linux-cp/ directory, originally by: Signed-off-by: Neale Ranns nranns@cisco.com Signed-off-by: Matthew Smith mgsmith@netgate.com Signed-off-by: Jon Loeliger jdl@netgate.com Signed-off-by: Pim van Pelt pim@ipng.nl Signed-off-by: Neale Ranns neale@graphiant.com
See previous work: https://gerrit.fd.io/r/c/vpp/+/30759 (interface mirroring) https://gerrit.fd.io/r/c/vpp/+/31122 (netlink listener)
It's intended to be re-submitted for review as a cleanup/rewrite of the existing Linux CP interface mirror and netlink syncer.