CAN Error Utilities

Simulate and monitor CAN bus error messages using Linux and SocketCAN.

This project provides two powerful tools:

1. canerrsim: A CAN error frame simulator for generating custom error conditions.
2. canerrdump: A CAN error frame monitor for real-time error analysis.

Whether you're testing CAN controllers, debugging protocol implementations, or learning about CAN error handling, these tools are designed to make your life easier.

Tools Overview

canerrsim (CAN Error Frame Simulator)

• Generates custom CAN error frames for testing and development purposes

• Simulates 30+ different CAN error conditions

• Supports error class, arbitration loss, protocol errors, transceiver faults

• Customizable error counters and data payload

• Real-time error frame generation

• Now part of can-utils

canerrdump (CAN Error Frame Monitor)

• Displays detailed error frame information from CAN interfaces
• Flexible error filtering options
• Human-readable error descriptions
• Real-time error monitoring
• Protocol violation location decoding

Supported Error Categories

mindmap
  root((CAN Error Coverage))
    )Controller Errors(
      OverflowRX
      OverflowTX
      WarningRX
      WarningTX
      PassiveRX
      PassiveTX
      Active
      CtrlUnspec
    )Protocol Errors(
      )Type(
        SingleBit
        FrameFormat
        BitStuffing
        Bit0
        Bit1
        BusOverload
        ActiveAnnouncement
        TX
        ProtUnspec
      )Location(
        SOF
        ID28_21
        ID20_18
        SRTR
        IDE
        ID17_13
        ID12_05
        ID04_00
        RTR
        RES1
        RES0
        DLC
        DATA
        CRC_SEQ
        CRC_DEL
        ACK
        ACK_DEL
        EOF
        INTERM
    )Transceiver Faults(
      TransUnspec
      CanHiNoWire
      CanHiShortToBAT
      CanHiShortToVCC
      CanHiShortToGND
      CanLoNoWire
      CanLoShortToBAT
      CanLoShortToVCC
      CanLoShortToGND
      CanLoShortToCanHi
    )Error Classes(
      TxTimeout
      LostArBit
      NoAck
      BusOff
      BusError
      Restarted
      )Count(
        TX
        RX

Loading

Each error type corresponds to specific CAN error frame constructions within the source code, with canerrsim building appropriate error frames and canerrdump decoding them into human-readable formats. All SocketCAN errors known at the time of writing are supported.

Installation

Dependencies

• Linux kernel with SocketCAN support (in general any newer then 2009)
• Ubuntu/Debian development tools:

  sudo apt-get install build-essential

• Optional: If you do not have real CAN adapter then Virtual CAN adapter vcan0 can be set up like this:

  sudo modprobe vcan
  sudo ip link add dev vcan0 type vcan                         
  sudo ip link set vcan0 mtu 72              # needed for CAN FD
  sudo ip link set vcan0 up
  

Download and Compilation

# Download
git clone https://github.com/zeljkoavramovic/canerrsim.git
cd canerrsim

# Build both tools
gcc canerrsim.c -o canerrsim
gcc canerrdump.c -o canerrdump

# Set execute permissions
chmod +x canerrsim canerrdump

Documentation

Start canerrsim or canerrdump without any parameters to see documentation for their usage.

Usage Examples

canerrsim

# Simulate bus-off with arbitration loss on vcan0
./canerrsim vcan0 BusOff LostArBit=12

# Generate protocol error with custom data
./canerrsim can0 FrameFormat Data3=AA Data5=FF ShowBits

# Complex error scenario
./canerrsim vcan0 TxTimeout NoAck CanHiShortToGND WarningRX

canerrdump

# Monitor all errors on can0
./canerrdump can0

# Filter specific errors on vcan0
./canerrdump vcan0 IgnoreTxTimeout IgnoreCounters

# Show error mask bits on can1
./canerrdump can1 ShowBits

Combined Usage

# In terminal 1:
./canerrdump vcan0

# In terminal 2:
./canerrsim vcan0 LostArBit=09 Data4=AA TX BusOff NoAck ShowBits

License

Dual-licensed under:

• LGPL-2.1-or-later
• BSD-3-Clause

History

Originally, canerrsim and canerrdump were developed in FreePascal as part of my SocketCAN wrappers. However, since I frequently use can-utils and install them on every CAN-enabled Linux system, I wanted to include these tools in the suite as well. To achieve this, I rewrote both tools in C and submitted a patch. While only canerrsim was accepted into the official repository, I decided to keep both tools here because canerrdump offers a more human-friendly output compared to candump.

Support the Project

If this project has helped you, support is most welcome:

• ⭐ Star the repository to show your appreciation.
• 💬 Share your feedback or success stories in Discussions.