XDP in virtual Ethernet devices

XDP in virtual Ethernet devices

[Sebastião Santos Boavida Amaro]

Hello!
I am trying to use xdp_stats[1] (this program prints packets 
passed/dropped) on the ethernet devices created by docker 
containers(veth). I have iperf exchanging messages between containers 
but xdp_stats does not capture any of the packets (XDP_PASS values do 
not change) and CPU usage goes to 100%. It works fine on my laptop's 
network device, but I have these issues with the docker network devices 
and I don't understand why.

https://github.com/xdp-project/xdp-tutorial/tree/master/basic04-pinning-maps

Best Regards,
Sebastião Amaro

Re: XDP in virtual Ethernet devices

[Toke Høiland-Jørgensen]

Sebastião Santos Boavida Amaro
<sebastiao.amaro@tecnico.ulisboa.pt> writes:

> Hello!
> I am trying to use xdp_stats[1] (this program prints packets 
> passed/dropped) on the ethernet devices created by docker 
> containers(veth). I have iperf exchanging messages between containers 
> but xdp_stats does not capture any of the packets (XDP_PASS values do 
> not change) and CPU usage goes to 100%. It works fine on my laptop's 
> network device, but I have these issues with the docker network devices 
> and I don't understand why.

I don't think there's anything special about the veth devices Docker
creates; so my immediate thought would be that this is due to
differences in the kernel versions you're running on your laptop vs on
docker. Some more details on this would be required to say anything
more, though...

-Toke

Re: XDP in virtual Ethernet devices

[Sebastião Santos Boavida Amaro]

Thank you for the reply!
After experimenting more the problem is not related to docker 
specifically but to the docker networks. When I run the same experiment 
outside a docker network I am able to capture packets, however, when the 
containers are deployed in a docker network I cannot capture packets. 
Does anyone know why this might happen? Or was able to capture the 
packets of docker containers inside networks?
Best Regards,
Sebastião Amaro

A 2021-06-01 14:12, Toke Høiland-Jørgensen escreveu:
> Sebastião Santos Boavida Amaro
> <sebastiao.amaro@tecnico.ulisboa.pt> writes:
> 
>> Hello!
>> I am trying to use xdp_stats[1] (this program prints packets
>> passed/dropped) on the ethernet devices created by docker
>> containers(veth). I have iperf exchanging messages between containers
>> but xdp_stats does not capture any of the packets (XDP_PASS values do
>> not change) and CPU usage goes to 100%. It works fine on my laptop's
>> network device, but I have these issues with the docker network 
>> devices
>> and I don't understand why.
> 
> I don't think there's anything special about the veth devices Docker
> creates; so my immediate thought would be that this is due to
> differences in the kernel versions you're running on your laptop vs on
> docker. Some more details on this would be required to say anything
> more, though...
> 
> -Toke