openvpn + openvswitch : goal to copy traffic from tun device

belette

Hi,

I am trying to find a way to copy all the packet from the tun device from openvpn to a monitoring system.
My system is using openvswitch and OVS has mirroring capability but it is a virtual switch and it is not possible to add a tun level 3 interface on it...
So I have created a veth interfaces, my idea would be to use one of the pair interface with openvpn then all the packets would be copied to the pair interface and adding this pair interface to openvswitch gives me the visibility i would like to obtain..

But it is ilike impossible to do that : When I created the pair interface and launch openvpn it is complaining and ends up with an error :

ERROR: Cannot ioctl TUNSETIFF tnic_vpn: Invalid argument (errno=22)

Is there a way to make openvpn works with veth interface (on the same host system, no namespace)
Or is there any way / tips to find a way to achieve my goal?

Many thanks for your help
belette

belette

The only workaround I have found for now is to use iptables -TEE option to send to a other interface a copy of the traffic

It is not as elegant as I would like ...any idea or tips are welcomed 🙂

Many thanks