The Intrig Message Decoder

Table of Contents

• 1. Introduction
  • 1.1. Quick Start
  • 1.2. Dependencies
• 2. Using Xenon
  • 2.1. Converting 3GPP asn.1 to XDDL

1. Introduction

Intrig Xenon provides flexible, powerful and easy to use C++ API for decoding protocol messages.

Originally developed for 3G and 4G programmers and test engineers to decode their complex messages, the xenon decoder has evolved into a general purpose open source tool with an ever expanding protocol support base.

Support for 5G is underway. See progress at #44

And, using XDDL, you can support your own proprietary message formats.

See xenon in action for yourself using the Intrig online decoder: SMS Message

1.1. Quick Start

Xenon is a CMake based project. It builds on Linux, MacOS, and Windows.

A Makefile is provided for convenience only and can be used on MacOS and Linux.

1.1.1. Building on Mac and Linux

git clone --recurse-submodules http://github.com/intrig/xenon.git
cd xenon
cmake -B build -S . -GNinja -DCMAKE_BUILD_TYPE=Release
cmake --build build
cmake --install build -v

For MacOS you can also use -Gxcode in the above cmake command to make an xcode project in the xcode subdirectory.

1.1.2. Building on Windows

Windows requires the following steps:

1. Clone the xenon repo as above.

2. Using a recent version of Visual Studio, select menu item "File/Open/Folder…​" and select the top level xenon directory.

3. Select menu item "Build/Build All"

4. Select menu item "Test/Run CTests" for xenon

This currently builds a static libary.

1.2. Dependencies

• Cmake

• Ninja

• C++17 or later compiler

Checkout the .github/workflow/ccpp.yml file to see how these are installed for the CI system on the latest OS versions.

2. Using Xenon

Link with the libxenon.so library, found in:

• /usr/local/lib//libxenon.so on Linux,

• /usr/local/lib/libxenon.dylib on MacOS.

• C:\Program Files (x86)\xenon\lib\xenon.lib on Windows.

Header files:

• /usr/local/include/xenon on MacOS and Linux,

• C:\Program Files (x86)\xenon\include\xenon on Windows.

The XDDL data files:

• /usr/local/share/xddl on MacOS and Linux,

• C:\Program Files (x86)\xenon\share\xddl on Windows.

See the xenon/examples directory for some common uses of the decoder.

If you want to parse your own custom protocols, then the XDDL Reference is a complete reference containing useful examples.

Also, the tools directory contains useful examples, such as xenon-dm and xenon-xv. These two programs are installed into /usr/local/bin.

2.1. Converting 3GPP asn.1 to XDDL

asnx converts asn.1 PER files to xddl. It handles a subset of the asn.1 spec. If there any problems please submit an issue.

For 3GPP specs, e.g. 36.331:

1. Download the latest pdf spec.

2. Save it to text file, e.g. 36.331.txt.

   Ubuntu the pdftotext command can be used, for example:

   pdftotext -nopgbrk -layout ts_136331v150700p.pdf 36.331.txt

3. Run: asn-strip -m 36.331.txt > 36.331.asn

4. Run: asnx -o TS-36.331.xddl -t 36.331.asn

   Edit 36.331.asn by hand. Some of the lines may have been broken at '-' characters. Fix the errors by hand and run the above step repeatedly until you fixed the errors.

5. Add resulting xddl file to git.

Enjoy!