Hello Marc,

On 27.05.21 17:07, Marc Kleine-Budde wrote:

I was wondering what the RX, TX and echo semantics on vxcan interfaces
should be.

I have started a "cangen" in one namespace and a "candump" in other.

The "candump" in the receiving namespace shows the CAN frames as "TX"
and in the sending namespace the CAN frames don't show up in a "candump"
at all. Is this intentional? If so what's the idea behind this and is
this documented?

I'm adding "cangw" to the mix and see what happens....

Yes. That is needed ...

If you take a look at slide 19 here:
https://wiki.automotivelinux.org/_media/agl-distro/agl2018-socketcan.pdf

The difference to vcan's (which are providing a local echo 
functionality) the vxcan's are more like veth's:

Providing a link between two namespaces but nothing more.

The question is if it would make sense to provide an additional local 
echo in vxcan_xmit() when sending to a vxcan?

When deriving vxcan from veth I probably had a some weird thoughts why 
that local echo could add problems. But while looking at it now, 
creating a second skb for a local echo on the side where the CAN frame 
is put into the vxcan seems applicable.

What do you think?

Best,
Oliver