Investigate how VLAN tags work under Linux Native

[salcock]

Today we noticed that using int: or ring: to capture traffic via a mirrored switch port was resulting in the VLAN tags being stripped from the packets. I didn't have time to follow this up too closely, but we want to be careful about avoiding any situations where VLAN tags are being popped / discarded prior to capture.

This is particularly important for our own capture setups, as we will probably be using either ring: or dpdk: in the future and we don't want to losing valuable information about the underlying network if we can avoid it.

[perry]

Linux makes the network cards do this (if they support it). It's very frustrating.

[brad]

Should be able to use ethtool to turn off "rxvlan" and "txvlan" offloads.