Create a Tool to allow user to run TCPUMP on interface

[brahmastra2016]

VFD take away the capability of running TCPDUMP , which i think is a MUST have function while trying to troubleshoot.

[azelezniak]

Debugging SR-IOV devices have always been challenging, and are working on VFd enhancements to allow troubleshooting easier.

[ScottDaniels]

It's not VFd, but a function of the DPDK driver which is bound to the VF.

Now that mirroring has been added to VFd, it is possible to turn on mirroring for a VF (inbound packets, outbound packets, or both) with the mirrored packets directed to another VF on the same PF. If a guest is started and attached to the VF receiving the mirrored packets, tcpdump (or other sniffer application) can be used in the guest to see the packets which were received and/or sent to the VF in question.

It should be noted that packets which are received, but cannot be delivered to the VF (incorrect VLAN or MAC) will not be mirrored, and only packets that are not dropped by the NIC on transmit (spoofed packets) are mirrored.

There is more detail in the various documents on the wiki with regard to debugging and specifically that cover how to set up and mirror traffic.