I want to setup a virtual SocketCAN interface on boot. The following lines do what I want (manually):
ip link add dev vcan0 type vcan ip link set up vcan0 (or)
ip link add dev vcan0 up type vcan I have a method to bring up a physical USB CAN interface on hotplugging - I add the following lines to /etc/network/interfaces:
allow-hotplug can0 iface can0 can static bitrate 250000 up /sbin/ip link set $IFACE down up /sbin/ip link set $IFACE up type can I now want to bring up the vcan interface on boot, too. So I auto-added the vcan module and added those lines to /etc/network/interfaces:
auto vcan0 iface vcan0 can static bitrate 0 # NEEDED but not supported pre-up /sbin/ip link add dev $IFACE type vcan up /sbin/ip link set $IFACE up But strangely this approach does not work: on boot or when I run ifup vcan0 I get eighter the following error:
Configuring interface vcan0=vcan0 (can) /sbin/ip link add dev $IFACE type vcan ... ip link set vcan0 type can bitrate 0 RTNETLINK answers: Operation not supported Failed to bring up vcan0. .. when I add the line bitrate <somevalue> or I get
Configuring interface vcan0=vcan0 (can) Missing required variable: bitrate Missing required configuration variables for interface vcan0/can. Failed to bring up vcan0. .. when I omit the bitrate setting.
So it looks like I have to set bitrate and must not set it - at the same time.
What am I doing wrong here?
p.s. of course I could simply run the ip link add .. on startup but I'd like to use the same approach for both interfaces.
1 Answer
You have to load the vcan module at boot time. Edit /etc/modules for this and add the line
vcan Next, edit /etc/network/interfaces
auto vcan0 iface vcan0 inet manual pre-up /sbin/ip link add dev $IFACE type vcan up /sbin/ifconfig $IFACE up Finally, restart the interfaces:
sudo /etc/init.d/networking restart The vcan0 interface should pop up if you type
ifconfig in a terminal.
