Please enable CONFIG_CAN_VXCAN=m

[mariusmarais]

Describe the bug

Please enable CONFIG_CAN_VXCAN=m in the Raspberry Pi OS kernel configs.

The Pi is a very common host for CAN work (robotics, automotive, 3D printing), and containerised deployments of these stacks currently have no clean way to get CAN into a namespace.

An abomacombination of veth, mguentner/cannelloni & vcan can be made to work but it is 2 processes in two namespaces, error-prone, not production ready and has no clean rate-limiting option.

vxcan is the CAN equivalent of veth: a pair of virtual CAN interfaces where frames written to one end appear on the other. The standard pattern is a cangw rule bridging a physical canX to one end of a vxcan pair, with the other end moved into the container's namespace. It's a very small module, see drivers/net/can/vxcan.c

It would be ideal if this could be enabled on the branch backing the current Raspberry Pi OS stable release so existing install could pick it up, but I understand it might only be possible going forward, so I'm happy either way.

Steps to reproduce the behaviour

$ for m in can can_raw can_gw vcan vxcan; do modinfo "$m" &>/dev/null && echo "[✓] $m" || echo "[✗] $m"; done
[✓] can
[✓] can_raw
[✓] can_gw
[✓] vcan
[✗] vxcan

$ grep -i vxcan /boot/config-$(uname -r)
# CONFIG_CAN_VXCAN is not set

$ modprobe vxcan
modprobe: FATAL: Module vxcan not found in directory /lib/modules/6.18.39+rpt-rpi-2712

Device (s)

Raspberry Pi 5

System

$ cat /etc/rpi-issue
Raspberry Pi reference 2026-06-18
Generated using pi-gen, https://github.com/RPi-Distro/pi-gen, ca8aeed0ae300c2a89f55ce9617d5f96a27e99e5, stage2

$ vcgencmd version
2026/08/12 00:06:56
Copyright (c) 2012 Broadcom
version f5e89631 (release) (embedded)

$ uname -a
Linux pi5 6.18.39+rpt-rpi-2712 #1 SMP PREEMPT Debian 1:6.18.39-1+rpt1 (2026-07-29) aarch64 GNU/Linux

Logs

No response

Additional context

No response

[pelwell]

#7592 adds the required config changes. After about 25 minutes you should be able to install a trial build of the kernel including that patch by running sudo rpi-update pulls/7592, after first reading the caveats.

[mariusmarais]

Works perfectly, thank you.

FWIW, I tested like this, exactly like a veth 👍🏼

$ modprobe vxcan

$ ip netns add cantest
$ ip link add vpair0 type vxcan peer name vpair0-0
$ ip link set vpair0 up

$ ip link set vpair0-0 netns cantest
$ ip netns exec cantest ip link set vpair0-0 name can0
$ ip netns exec cantest ip link set can0 up

# view from root
$ ip -br link
lo               UNKNOWN        00:00:00:00:00:00 <LOOPBACK,UP,LOWER_UP>
end0             DOWN           2c:cf:67:14:b5:9d <NO-CARRIER,BROADCAST,MULTICAST,UP>
wlan0            UP             2c:cf:67:14:b5:9e <BROADCAST,MULTICAST,UP,LOWER_UP>
vpair0@if4       UP             <NOARP,UP,LOWER_UP>

# view from cantest namespace
$ ip netns exec cantest ip -br link
lo               DOWN           00:00:00:00:00:00 <LOOPBACK>
can0@if5         UP             <NOARP,UP,LOWER_UP>

# teardown
$ ip net del cantest

[pelwell]

Thanks - that's now merged and will be in future releases.