OnlineFix

A companion DLL for OpenSteamTool that fixes online play for games whose matchmaking runs outside Steam.

OpenSteamTool itself ships no payload — it only provides the generic injection layer. This OnlineFix DLL is loaded by that layer directly into the game process when it opens its Steam pipe.

Build

Visual Studio 2022 (Windows, primary)

Requires CMake 3.20+ and Visual Studio 2022 (MSVC x64).

cmake -B build -A x64
cmake --build build --config Release

Output: build/Release/OnlineFix.dll.

Cross-compile (Linux/macOS)

Requires CMake, Ninja (or make), and mingw-w64 (x86_64-w64-mingw32-*).

cmake -B build-mingw -DCMAKE_TOOLCHAIN_FILE=cmake/toolchains/mingw-w64.cmake
cmake --build build-mingw

Output: build-mingw/OnlineFix.dll. Add -DCMAKE_BUILD_TYPE=Debug to enable payload logging (mirrors the VS Debug config).

Usage

1. Drop OnlineFix.dll next to steam.exe (or anywhere; use an absolute path below).
2. Add an entry to opensteamtool.toml:

   [[inject]]
   path = "OnlineFix.dll"
   when_cmdline = "-onlinefix"

3. Launch the game with -onlinefix in its Steam launch options.

Disclaimer

For research and educational purposes only. You are responsible for complying with local laws, platform terms of service, and software licenses.