如何使用Wireshark分析CANopen？Ubuntu环境下过滤失效问题求助

Let's walk through the most likely issues and fixes step by step, like we would on a real dev forum:

1. First, Confirm You're Actually Capturing CAN Frames on vcan0 #

If Wireshark isn't seeing any raw CAN traffic on vcan0, filtering for canopen will naturally return nothing. Here's how to verify and fix this:

• Open a terminal and check if vcan0 is active:

  ip link show vcan0
  

  If it doesn't exist, create and enable the virtual CAN interface first:

  sudo modprobe vcan
  sudo ip link add dev vcan0 type vcan
  sudo ip link set up vcan0
  

• In Wireshark, select vcan0 from the interface list and start capturing. Try filtering with can instead of canopen — if you see raw CAN frames (with IDs, data fields, etc.), your capture setup is working. If not, double-check your vcan interface configuration.

2. Force Wireshark to Decode CAN Frames as CANopen #

Older Wireshark versions (like 2.2.6) don't always auto-detect CANopen traffic. You need to manually tell it to parse the frames correctly:

• While capturing, right-click any raw CAN frame in the packet list.
• Hover over Decode As → click Decode As...
• In the dialog box, find the row where the "Current" column shows can (or the default protocol for your frames).
• Click the dropdown in the "Current" column and select CANopen.
• Click OK to save the setting.

Now try filtering with canopen again — you should see parsed CANopen traffic (NMT commands, SDO transfers, PDO messages, etc.).

3. Verify Your CAN Traffic Uses CANopen-Compliant IDs #

CANopen relies on specific 11-bit CAN ID ranges for different message types:

• NMT: 0x000
• SDO requests/responses: 0x600-0x6FF
• PDOs: 0x180-0x1FF, 0x200-0x2FF, etc.

If the CAN frames on vcan0 don't fall into these ranges, Wireshark won't recognize them as CANopen, even if you force decoding. Double-check the IDs of the traffic you're capturing.

4. Ensure Wireshark Has Full CANopen Support Installed #

On Ubuntu 16.04, make sure you have the complete Wireshark package (not a stripped-down version) installed. Run this in a terminal to verify or reinstall:

sudo apt-get install --reinstall wireshark wireshark-common

This ensures all necessary protocol plugins (including CANopen) are present and properly set up.

内容的提问来源于stack exchange，提问作者Marvin Noll