Socketcand is part of the Linux-CAN project, providing a Network-to-CAN bridge as a Linux damon. It implements a specific TCP/IP based communication protocol to transfer CAN frames and control commands.
The main advantage compared to UDP-based protocols (e.g. virtual interface) is, that TCP guarantees delivery and that the message order is kept.
Here is a small example dumping all can messages received by a socketcand daemon running on a remote Raspberry Pi:
import can bus = can.interface.Bus(bustype='socketcand', host="10.0.16.15", port=29536, channel="can0") # loop until Ctrl-C try: while True: msg = bus.recv() print(msg) except KeyboardInterrupt: pass
The output may look like this:
Timestamp: 1637791111.209224 ID: 000006fd X Rx DLC: 8 c4 10 e3 2d 96 ff 25 6b Timestamp: 1637791111.233951 ID: 000001ad X Rx DLC: 4 4d 47 c7 64 Timestamp: 1637791111.409415 ID: 000005f7 X Rx DLC: 8 86 de e6 0f 42 55 5d 39 Timestamp: 1637791111.434377 ID: 00000665 X Rx DLC: 8 97 96 51 0f 23 25 fc 28 Timestamp: 1637791111.609763 ID: 0000031d X Rx DLC: 8 16 27 d8 3d fe d8 31 24 Timestamp: 1637791111.634630 ID: 00000587 X Rx DLC: 8 4e 06 85 23 6f 81 2b 65
The following section will show how to get the stuff installed on a Raspberry Pi with a MCP2515-based CAN interface, e.g. available from Waveshare. However, it will also work with any other socketcan device.
Install CAN Interface for a MCP2515 based interface on a Raspberry Pi#
Add the following lines to
Please take care on the frequency of the crystal on your MCP2515 board:
/boot/config.txt has been modified.
Enable socketcan for can0#
Create config file for systemd-networkd to start the socketcan interface automatically:
cat >/etc/systemd/network/80-can.network <<'EOT' [Match] Name=can0 [CAN] BitRate=250K RestartSec=100ms EOT
systemd-networkd on reboot and start it immediately (if it was not already startet):
sudo systemctl enable systemd-networkd sudo systemctl start systemd-networkd
Build socketcand from source#
# autoconf is needed to build socketcand sudo apt-get install -y autoconf # clone & build sources git clone https://github.com/linux-can/socketcand.git cd socketcand ./autogen.sh ./configure make
./socketcand -v -i can0
During start, socketcand will prompt its IP address and port it listens to:
Verbose output activated Using network interface 'eth0' Listen adress is 10.0.16.15 Broadcast adress is 10.0.255.255 creating broadcast thread... binding socket to 10.0.16.15:29536