Troubleshooting canplayer on Virtual CAN (vcan0/vcan1) in Kali Linux 2024.3 (ARM64)

Using canplayer with virtual CAN interfaces can be tricky. Below are common issues and solutions to ensure CAN messages replay correctly on vcan0/vcan1 in Kali 2024.3 (ARM64), along with alternative methods for replaying CAN traffic.

Known Issues with canplayer and Virtual CAN

• Log File Format: canplayer expects the input log in the compact candump format (with timestamp in parentheses). If the log lines aren’t in the right format, canplayer may simply exit without sending anything [stackoverflow.com](https://stackoverflow.com/questions/31328302/canplayer-wont-replay-candump-files#:~:text=I'm trying to use canplayer,clue of what is happening) [stackoverflow.com](https://stackoverflow.com/questions/31328302/canplayer-wont-replay-candump-files#:~:text=Files in that format can,canplayer using the following commands). For example, a valid candump log line looks like:

  (1625159052.249713) vcan0 123#DEADBEEF
  

  Ensure you captured the log with a command like candump -l vcan0 or candump -L vcan0 > file.log so that each line starts with a (timestamp) and includes the interface name [stackoverflow.com](https://stackoverflow.com/questions/31328302/canplayer-wont-replay-candump-files#:~:text=(1436509052.249713) vcan0 044,68FF147114D1). Logs in this format can be directly replayed with canplayer -I <logfile> [stackoverflow.com](https://stackoverflow.com/questions/31328302/canplayer-wont-replay-candump-files#:~:text=Files in that format can,canplayer using the following commands) . If your log is in a different format (e.g. Vector ASC), use tools like asc2log (part of can-utils) to convert it.

• No Traffic on Listener: Remember that separate vcan interfaces are isolated CAN buses. If you send on vcan0 and listen on vcan1 without any bridge, you will not see any traffic on vcan1. This is a common misconception when simulating two nodes – by default vcan0 and vcan1 are not connected. All vcan interfaces act like independent CAN networks. So if canplayer replays onto vcan0, a candump on vcan1 will show nothing (and vice versa) unless you explicitly forward messages between them.

• Silent Failure Due to Missing Interface: By default, canplayer will try to send frames to the same interface names they were recorded from, unless told otherwise [manpages.debian.org](https://manpages.debian.org/testing/can-utils/canplayer.1.en.html#:~:text=extra hook%3A stdout%3Dcan0 ,they had been received from) . If those interface names don’t exist on your system, canplayer won’t deliver any frames (it may print an error or just fail quietly). For instance, replaying a log that was captured on can0/can1 will do nothing on a system that only has vcan0/vcan1 (since can0/can1 don’t exist). In such cases you must use interface mapping (explained below) to map log interfaces to your actual interface names.

• Kernel Module Issues (ARM64): On some ARM64 systems, the virtual CAN driver might not be pre-installed. Ensure the vcan kernel module is loaded. Run sudo modprobe vcan and then create the interfaces (ip link add dev vcan0 type vcan && ip link set up vcan0, same for vcan1). If modprobe vcan fails or if ifconfig vcan0 shows an unexpected type (e.g. NET/ROM instead of CAN), it means the vcan module is missing or incorrect [forum.beagleboard.org](https://forum.beagleboard.org/t/virtual-can-bus-vcan-interface-fails/37104#:~:text=Very strange%2C I can not,10gb.img) [forum.beagleboard.org](https://forum.beagleboard.org/t/virtual-can-bus-vcan-interface-fails/37104#:~:text=I get a weird interface,back with %3F%3FAMPR NET%2FROM). In one case, an ARM image lacked vcan.ko and an improperly built module showed up as netrom (causing candump vcan0 to report “No such device” [forum.beagleboard.org](https://forum.beagleboard.org/t/virtual-can-bus-vcan-interface-fails/37104#:~:text=I get a weird interface,back with %3F%3FAMPR NET%2FROM)). The solution was to rebuild and install the correct vcan module [forum.beagleboard.org](https://forum.beagleboard.org/t/virtual-can-bus-vcan-interface-fails/37104#:~:text=Very strange%2C I can not,10gb.img). On Kali 2024.3 (ARM64), vcan support should be present by default (Kali’s kernel includes SocketCAN), but it’s worth verifying this if you see unusual errors. Use dmesg or lsmod | grep vcan to confirm the module loaded successfully.

Proper Interface Mapping in canplayer

If the log’s interface names don’t match your current interface (or you want to redirect traffic to a different interface), use interface mapping with canplayer. The syntax is <write-if>=<log-if>. For example:

• canplayer vcan1=vcan0 -I dump.log – This reads frames recorded on vcan0 (in the log) and sends them out on vcan1. Here <log-if> is vcan0 (from the file) and <write-if> is vcan1 (the interface to transmit on) manpages.debian.org.

• canplayer vcan0=can0 -I dump.log – This maps frames originally on can0 to vcan0. Any log entry tagged as can0 will be output via vcan0 manpages.debian.org . Similarly, you could map can1 to vcan1 if the log contains can1 frames [jlwranglerforums.com](https://www.jlwranglerforums.com/forum/threads/jeep-hacking-can-c-can-ihs-uds-reverse-engineering.82139/page-26#:~:text=If you create both a,to launch canplayer like this).

You can specify multiple mappings if the log contains multiple interfaces. For example, if the log has traffic from both can0 and can1, and you have set up vcan0/vcan1, run:

canplayer vcan0=can0 vcan1=can1 -I dual.log

This will replay can0 frames onto vcan0 and can1 frames onto vcan1 [jlwranglerforums.com](https://www.jlwranglerforums.com/forum/threads/jeep-hacking-can-c-can-ihs-uds-reverse-engineering.82139/page-26#:~:text=If you create both a,to launch canplayer like this). (The naming can be counter-intuitive – remember it’s always <playTo>=<recordedFrom>.)

Tips:

• If you don’t provide any interface mapping, canplayer assumes the replay interfaces have the same names as in the log [manpages.debian.org](https://manpages.debian.org/testing/can-utils/canplayer.1.en.html#:~:text=extra hook%3A stdout%3Dcan0 ,they had been received from). This only works if you actually have those interfaces up. For example, if your log was recorded on vcan0 and vcan0 is still up, you can do canplayer -I file.log and it will transmit on vcan0 by default [manpages.debian.org](https://manpages.debian.org/testing/can-utils/canplayer.1.en.html#:~:text=extra hook%3A stdout%3Dcan0 ,they had been received from). But if you want to simulate a different node receiving it, use the mapping to send to vcan1 as shown above.
• You can also map to stdout as a special case (e.g. stdout=can0) to print frames instead of sending, which is useful for debugging log contents manpages.debian.org.
• Double-check that you’ve created and brought up the target interface before running canplayer. If you mapped to vcan1 but forgot ip link set vcan1 up, no frames will actually transmit (and you might see an error).

Kernel/Package Compatibility in Kali 2024.3

Kali Linux 2024.3 (ARM64) is based on a modern Linux kernel with SocketCAN support, so core compatibility is generally good. However, consider the following:

• Kernel Version vs. can-utils Version: Ensure your can-utils (which includes canplayer) is up-to-date. Kali 2024.3 likely ships with a recent can-utils release (2023.x). This version supports CAN FD and even CAN XL features, which requires a sufficiently new kernel. The Kali 2024.3 kernel (Linux 6.x series) does support CAN FD and standard CAN features, so there’s no fundamental incompatibility reported. In short, the standard CAN replay on vcan should work out-of-the-box. If you suspect an issue, run canplayer -V (if available) or check the package version to see if it’s an older release. If it’s very old, consider upgrading or reinstalling can-utils.
• Module and SocketCAN Config: As mentioned, verify that the vcan module is loaded. On Raspberry Pi or ARM devices, Kali’s kernel should include it, but in case of a custom kernel, you might need to compile it. After modprobe vcan, creating vcan0/vcan1 with ip link should result in CAN-specific settings (MTU 72 bytes, NOARP flag, type UNSPEC in ifconfig) – indicating a proper CAN interface [forum.beagleboard.org](https://forum.beagleboard.org/t/virtual-can-bus-vcan-interface-fails/37104#:~:text=Now it works!). If you see an mtu 0 or a NET/ROM type, that’s a sign something is wrong with the vcan driver (as one BeagleBoard user discovered) [forum.beagleboard.org](https://forum.beagleboard.org/t/virtual-can-bus-vcan-interface-fails/37104#:~:text=I get a weird interface,back with %3F%3FAMPR NET%2FROM). Rebuilding the module or using a kernel with CAN networking enabled is the fix in that rare case.
• ARM64 Endianness/Alignment: There are no known architecture-specific issues with can-utils on ARM64 for basic usage. canplayer uses standard SocketCAN APIs which behave the same on ARM and x86. So, if something isn’t working on Kali ARM64, it’s likely due to configuration, not an inherent ARM bug.
• User-space vs Kernel-space timestamps: canplayer relies on log timestamps to schedule messages. These timestamps are usually from candump. If you recorded on one machine and replay on another much faster/slower device, the timing should still be honored. But if you see extremely slow or fast replays, you can use options like -t (ignore timestamps) or -g <ms> (add fixed gap) to adjust timing manpages.debian.org manpages.debian.org. This isn’t a compatibility issue per se, but something to keep in mind if replay appears incorrect due to timing differences.

Solutions and Alternative Replay Methods

If you continue to have issues with canplayer on vcan interfaces, try these troubleshooting steps and alternatives:

• Step-by-Step Testing: Verify basic SocketCAN functionality first. For example, bring up a single vcan0 and use cansend/candump:

  1. sudo modprobe vcan; sudo ip link add dev vcan0 type vcan; sudo ip link set up vcan0
  2. In one terminal, run candump vcan0.
  3. In another terminal, run cansend vcan0 123#CAFEBABE. You should see the frame on the candump terminal. This confirms vcan0 works. If this fails, address it before blaming canplayer.
  4. Next, test canplayer on the same interface: Keep candump vcan0 running, and in the other terminal run canplayer -I mylog.log (assuming the log was recorded on vcan0). With loopback enabled (default), candump should print the replayed frames as they are sent [manpages.debian.org](https://manpages.debian.org/testing/can-utils/canplayer.1.en.html#:~:text=,verbose%3A print sent CAN frames). If you see nothing, add the -v flag (canplayer -v -I ...) to have canplayer print each frame it attempts to send [manpages.debian.org](https://manpages.debian.org/testing/can-utils/canplayer.1.en.html#:~:text=,verbose%3A print sent CAN frames). This will tell you if it’s reading the file correctly and which interface it’s using.
  5. If canplayer -v shows frames being sent on an interface (say can0) that you’re not monitoring, then the interface mapping is wrong – fix the mapping or bring up the expected interface.

• Use a Virtual CAN Bridge: If your goal is to have two virtual interfaces talk to each other (simulate two CAN nodes on one bus), the proper solution is to use the CAN gateway feature or a single bus:

  • Easiest: Use one vcan for both sender and receiver. You don’t actually need two vcan devices to simulate two nodes – multiple sockets can attach to vcan0. For example, run candump vcan0 and simultaneously use canplayer -I file.log on vcan0 (or any cansend/cangen); they will communicate over the same virtual bus.
  • If you specifically need two distinct interfaces, use the Linux CAN gateway (cangw) to forward traffic. Load the can-gw module (sudo modprobe can-gw) and add rules so that anything sent on vcan0 repeats on vcan1 and vice versa [stackoverflow.com](https://stackoverflow.com/questions/54296852/how-to-connect-two-vcan-ports-in-linux#:~:text=Then create gateway rules via,messages from vcan0 to vcan1) [stackoverflow.com](https://stackoverflow.com/questions/54296852/how-to-connect-two-vcan-ports-in-linux#:~:text=and the other way around%3A) :
    • sudo cangw -A -s vcan0 -d vcan1 -e (forward vcan0 -> vcan1) [stackoverflow.com](https://stackoverflow.com/questions/54296852/how-to-connect-two-vcan-ports-in-linux#:~:text=Then create gateway rules via,messages from vcan0 to vcan1)
    • sudo cangw -A -s vcan1 -d vcan0 -e (forward vcan1 -> vcan0) [stackoverflow.com](https://stackoverflow.com/questions/54296852/how-to-connect-two-vcan-ports-in-linux#:~:text=and the other way around%3A)
    • The -e flag copies the entire CAN frame (ID, data, etc.) unchanged. After this, vcan0 and vcan1 will echo each other’s traffic, effectively acting like a single bus [stackoverflow.com](https://stackoverflow.com/questions/54296852/how-to-connect-two-vcan-ports-in-linux#:~:text=sudo cangw ,e) . Now you can replay on vcan0 and candump on vcan1 (or vice versa) and see the messages. Note: This method replays all traffic both ways, so use it only if you need a full bidirectional link.

• Alternative Replay Tools: If canplayer is still not meeting your needs, consider alternative approaches:

  • Python CAN Libraries: Using Python with the python-can library, you can write a script to read a log file and send frames on a SocketCAN interface at specified intervals. This gives you more control for debugging. For instance, you could read each line of your candump log, parse the ID and data, then send on vcan0 using the library’s Bus.send() function, with delays corresponding to the timestamps.
  • cangen + scripting: For simple patterns, you might not need a full log replay. A combination of cangen (to generate traffic) and custom filters can mimic certain loads. However, cangen is random and not a true replay tool.
  • SavvyCAN or CANalyzers: If you have a GUI environment, tools like SavvyCAN (on Windows/Linux) or other CAN analyzers can import a log and replay it on a virtual interface. This is more heavy-weight and typically used for real CAN hardware, but worth mentioning if you’re open to graphical tools.
  • Custom C/C++ Tool: As a last resort (or for learning), you could write a small C program using SocketCAN (or use cansend in a loop via a script) to publish frames. Usually this isn’t necessary, but it’s an option if you suspect a bug in canplayer for your scenario.

• Debugging with Verbose Output: Always use canplayer -v during troubleshooting. It will print each frame as it’s sent (interface, ID, data) [manpages.debian.org](https://manpages.debian.org/testing/can-utils/canplayer.1.en.html#:~:text=,verbose%3A print sent CAN frames) . If you don’t see any output from -v, then canplayer isn’t reading your file at all – double-check the file path and format. If you do see output lines, verify the interface names in those lines. They should match the interface you intend to use for replay.

• Check for Errors: Monitor dmesg for any CAN-related error messages when running canplayer. Although rare, you might see socket errors or buffer issues. For example, a very fast replay can overrun buffers and show No buffer space available errors in console (which indicates the send queue is full). In such cases, consider adding a gap (e.g. -g 5 for 5ms gap) or limit the loop rate.

In summary, ensure your virtual CAN setup is correct and that you use canplayer with the proper interface mapping. Kali 2024.3 on ARM64 does not have known incompatibilities with SocketCAN, so most issues boil down to usage. By following the above steps – verifying log format, using mappings for vcan interfaces, and employing debugging flags – you should be able to get canplayer to replay messages correctly. And if not, the alternative methods (like cangw bridging or a custom replay script) can serve as effective workarounds to achieve your CAN bus simulation goals.

Sources:

• Oliver Hartkopp & Arthur Nunes – Using candump and canplayer (Stack Overflow) [stackoverflow.com](https://stackoverflow.com/questions/31328302/canplayer-wont-replay-candump-files#:~:text=(1436509052.249713) vcan0 044,68FF147114D1) [stackoverflow.com](https://stackoverflow.com/questions/31328302/canplayer-wont-replay-candump-files#:~:text=Files in that format can,canplayer using the following commands)
• Linux can-utils Manual – canplayer interface assignment syntax manpages.debian.org
• Jeep Forum – Example of mapping CAN log to vcan interfaces [jlwranglerforums.com](https://www.jlwranglerforums.com/forum/threads/jeep-hacking-can-c-can-ihs-uds-reverse-engineering.82139/page-26#:~:text=If you create both a,to launch canplayer like this)
• BeagleBoard Forum – vcan module issues on ARM64 and resolution [forum.beagleboard.org](https://forum.beagleboard.org/t/virtual-can-bus-vcan-interface-fails/37104#:~:text=Very strange%2C I can not,10gb.img) [forum.beagleboard.org](https://forum.beagleboard.org/t/virtual-can-bus-vcan-interface-fails/37104#:~:text=I get a weird interface,back with %3F%3FAMPR NET%2FROM)
• Stack Overflow – Connecting two vcan networks with cangw [stackoverflow.com](https://stackoverflow.com/questions/54296852/how-to-connect-two-vcan-ports-in-linux#:~:text=Then create gateway rules via,messages from vcan0 to vcan1) [stackoverflow.com](https://stackoverflow.com/questions/54296852/how-to-connect-two-vcan-ports-in-linux#:~:text=and the other way around%3A)