Wireshark dissector for RCT Serial Communication Protocol - Proof of Concept

The code in this repository is an experimental protocol dissector for the RCT Serial Communication Protocol by RCT Power GmbH for use with Wireshark.

This is a Proof of Concept (PoC)

I will not pursue the project further myself, though I'll most likely accept PRs. I am not fluent in LUA, getting this state to work was enough of a challenge for me and taught me that I'm better off with writing my own special-purpose tools (python-rctclient).

The dissector uses the LUA API to interface with Wireshark. It contains a hardcoded list of OIDs extracted from the Registry of python-rctclient.

Installation

On Linux, drop the *.lua-files into ${HOME}/.local/lib/wireshark/plugins/. You may need to tell Wireshark to use the dissector by right-clicking on a TCP-Frame and setting up port 8899 to be dissected as rctserial. Once this is working, you can simply filter for rctserial and expand the packet contents.

Bugs

• Slow (probably my fault, but could be the LUA API as well)
• Buggy
• The CRC calculation is not working and checksum mismatches are ignored.
• Corner cases are ignored, such as packets that indicate a far too large payload.
• Frames spanning multiple TCP packets are not handled.

Files

• rctdata.lua contains the OID information (generated file).
• rctserial.lua is the actual dissector.
• rctutils.lua contains helper functions.

Example