TcpLicenseServer

A lightweight, high-performance TCP server designed for handling software licensing, user authentication, and remote configuration management. Built with .NET (C#), it utilizes a command pattern architecture, SQLite for data persistence, and Serilog for robust logging.

🚀 Features

• TCP Socket Communication: Fast, raw socket communication using TcpListener.
• Asynchronous Architecture: Fully async/await implementation for handling multiple concurrent clients.
• Authentication System:
  • Key-based login.
  • HWID Locking: Binds a license key to a specific hardware ID.
  • Subscription expiration checks.
  • Ban system.
• Role-Based Access Control: Decorator-based permission system (AdminOnlyAttribute) to separate Admin and User commands.
• Remote Configuration: Users can store and retrieve JSON configurations associated with their license.
• Extensible Command Pattern: Easily add new commands by implementing the ICommand interface.
• Data Persistence: Uses Entity Framework Core with SQLite.

🛠️ Tech Stack

• Language: C# (.NET 10.0 recommended)
• ORM: Entity Framework Core
• Database: SQLite (licenseServer.db)
• Logging: Serilog (Console & File)

📦 Getting Started

Prerequisites

• .NET SDK installed.

Installation

1. Clone the repository:

   git clone https://github.com/larkliy/TcpLicenseServer.git

2. Navigate to the project directory:

   cd TcpLicenseServer/TcpLicenseServer

3. Build the project:

   dotnet build

4. Run the server:

   dotnet run

   The server will automatically create the licenseServer.db database file on the first run.

📡 Protocol & Usage

The server communicates via text-based commands over TCP on port 8080. Format: COMMAND arg1 arg2 ...

Authentication

To access any functionality, the client must first log in.

• Command: LOGIN [LicenseKey] [HWID]
• Example: LOGIN admin-secret-key MyCpuId123

User Commands

Available to all authenticated users.

Command	Arguments	Description
CONFIGCREATE	[Name] [JSON content]	Saves a new configuration string.
GETCONFIG	[Name]	Retrieves a specific configuration.
GETCONFIGS	None	Lists all configurations owned by the user.

Admin Commands

Available only if the user has the Admin role.

Command	Arguments	Description
USERCREATE	[Key] [Role] [SubEndDate]	Creates a new user. Default role is "User".
USERBANUNBAN	[Key]	Toggles the ban status of a user.
USERHWIDUPDATE	[Key] [NewHWID]	Resets or updates a user's HWID binding.
USERSUBSCRIPTIONDATEUPDATE	[Key] [DateTime]	Extends or reduces a subscription.
USERINFO	[Key]	Returns full JSON details about a user.
GETALLUSERS	[Page] [Size]	Lists all users (paginated).
GETALLCONFIGS	[Page] [Size]	Lists all configs on the server.

📂 Project Structure

• Commands/: Contains logic for all executable commands.
• Decorators/: Handles middleware logic like AuthGuard and CheckOnAdmin.
• Data/: EF Core DbContext and database configuration.
• Models/: Database entities (User, Config) and session models.
• MainServer.cs: Handles the TCP listener and client acceptance loop.
• CommandFactory.cs: Uses Reflection to dynamically register commands.

🚧 Current Status & Limitations

This server is currently a prototype.

Pull requests and contributions are welcome!

📝 License

This project is open-source. Feel free to modify and distribute it as needed.