The full documentation for socketcan can be found in the kernel docs at networking/can.txt.


Versions before 2.2 had two different implementations named socketcan_ctypes and socketcan_native. These are now deprecated and the aliases to socketcan will be removed in version 3.0. Future 2.x release may raise a DeprecationWarning.

Socketcan Quickstart

The CAN network driver provides a generic interface to setup, configure and monitor CAN devices. To configure bit-timing parameters use the program ip.

The virtual CAN driver (vcan)

The virtual CAN interfaces allow the transmission and reception of CAN frames without real CAN controller hardware. Virtual CAN network devices are usually named ‘vcanX’, like vcan0 vcan1 vcan2.

To create a virtual can interface using socketcan run the following:

sudo modprobe vcan
# Create a vcan network interface with a specific name
sudo ip link add dev vcan0 type vcan
sudo ip link set vcan0 up

Real Device

vcan should be substituted for can and vcan0 should be substituted for can0 if you are using real hardware. Setting the bitrate can also be done at the same time, for example to enable an existing can0 interface with a bitrate of 1MB:

sudo ip link set can0 up type can bitrate 1000000

Send Test Message

The can-utils library for linux includes a script cansend which is useful to send known payloads. For example to send a message on vcan0:

cansend vcan0 123#DEADBEEF

CAN Errors

A device may enter the “bus-off” state if too many errors occurred on the CAN bus. Then no more messages are received or sent. An automatic bus-off recovery can be enabled by setting the “restart-ms” to a non-zero value, e.g.:

sudo ip link set canX type can restart-ms 100

Alternatively, the application may realize the “bus-off” condition by monitoring CAN error frames and do a restart when appropriate with the command:

ip link set canX type can restart

Note that a restart will also create a CAN error frame.

List network interfaces

To reveal the newly created can0 or a vcan0 interface:


Display CAN statistics

ip -details -statistics link show vcan0

Network Interface Removal

To remove the network interface:

sudo ip link del vcan0


Wireshark supports socketcan and can be used to debug python-can messages. Fire it up and watch your new interface.

To spam a bus:

import time
import can

bustype = 'socketcan'
channel = 'vcan0'

def producer(id):
    """:param id: Spam the bus with messages including the data id."""
    bus = can.interface.Bus(channel=channel, bustype=bustype)
    for i in range(10):
        msg = can.Message(arbitration_id=0xc0ffee, data=[id, i, 0, 1, 3, 1, 4, 1], extended_id=False)
    # Issue #3: Need to keep running to ensure the writing threads stay alive. ?


With debugging turned right up this looks something like this:


The process to follow bus traffic is even easier:

for message in Bus(can_interface):

Reading and Timeouts

Reading a single CAN message off of the bus is simple with the bus.recv() function:

import can

can_interface = 'vcan0'
bus = can.interface.Bus(can_interface, bustype='socketcan')
message = bus.recv()

By default, this performs a blocking read, which means bus.recv() won’t return until a CAN message shows up on the socket. You can optionally perform a blocking read with a timeout like this:

message = bus.recv(1.0)  # Timeout in seconds.

if message is None:
    print('Timeout occurred, no message.')

If you set the timeout to 0.0, the read will be executed as non-blocking, which means bus.recv(0.0) will return immediately, either with a Message object or None, depending on whether data was available on the socket.


The implementation features efficient filtering of can_id’s. That filtering occurs in the kernel and is much much more efficient than filtering messages in Python.

Broadcast Manager

The socketcan interface implements thin wrappers to the linux broadcast manager socket api. This allows the cyclic transmission of CAN messages at given intervals. The overhead for periodic message sending is extremely low as all the heavy lifting occurs within the linux kernel.


An example that uses the send_periodic is included in python-can/examples/

The object returned can be used to halt, alter or cancel the periodic message task.

class can.interfaces.socketcan.CyclicSendTask(channel, message, period, duration=None)[source]

Bases: can.broadcastmanager.LimitedDurationCyclicSendTaskABC, can.broadcastmanager.ModifiableCyclicTaskABC, can.broadcastmanager.RestartableCyclicTaskABC

A socketcan cyclic send task supports:

  • setting of a task duration
  • modifying the data
  • stopping then subsequent restarting of the task
  • channel (str) – The name of the CAN channel to connect to.
  • message (can.Message) – The message to be sent periodically.
  • period (float) – The rate in seconds at which to send the message.
  • duration (float) – Approximate duration in seconds to send the message.

Update the contents of this periodically sent message.

Note the Message must have the same arbitration_id like the first message.


Restart a stopped periodic task.


Send a TX_DELETE message to cancel this task.

This will delete the entry for the transmission of the CAN-message with the specified can_id CAN identifier. The message length for the command TX_DELETE is {[bcm_msg_head]} (only the header).


class can.interfaces.socketcan.SocketcanBus(channel='', receive_own_messages=False, fd=False, **kwargs)[source]

Bases: can.bus.BusABC

Implements can.BusABC._detect_available_configs().

  • channel (str) – The can interface name with which to create this bus. An example channel would be ‘vcan0’ or ‘can0’. An empty string ‘’ will receive messages from all channels. In that case any sent messages must be explicitly addressed to a channel using
  • receive_own_messages (bool) – If transmitted messages should also be received by this bus.
  • fd (bool) – If CAN-FD frames should be supported.
  • can_filters (list) – See can.BusABC.set_filters().

Block waiting for a message from the Bus.

Parameters:timeout (float) – seconds to wait for a message or None to wait indefinitely
Return type:can.Message or None
Returns:None on timeout or a can.Message object.
Raises:can.CanError – if an error occurred while reading
send(msg, timeout=None)[source]

Transmit a message to the CAN bus.

  • msg (can.Message) – A message object.
  • timeout (float) – Wait up to this many seconds for the transmit queue to be ready. If not given, the call may fail immediately.

can.CanError – if the message could not be written.

send_periodic(msg, period, duration=None)[source]

Start sending a message at a given period on this bus.

The kernel’s broadcast manager will be used.

  • msg (can.Message) – Message to transmit
  • period (float) – Period in seconds between each message
  • duration (float) – The duration to keep sending this message at given rate. If no duration is provided, the task will continue indefinitely.

A started task instance

Return type:



Note the duration before the message stops being sent may not be exactly the same as the duration specified by the user. In general the message will be sent at the given rate until at least duration seconds.


Closes the socket.