TCP Server-Client in C++

Exploring low-level networking with POSIX sockets, TCP/IP, Linux epoll, and concurrency in C++.

Features

• Multi-threaded TCP Server: Built using Linux epoll and non-blocking sockets for high-performance concurrent client handling.
• Thread Pool Architecture: Features a producer-consumer work queue to efficiently process requests under high workloads.
• Custom Binary Protocol: Implements robust message framing and serialization for low-overhead client-server communication.
• Connection Lifecycle Management: Handles client joins, disconnections, socket cleanup, and resource reclamation gracefully.
• Token-Bucket Rate Limiting: Built-in rate limiter to prevent request flooding and ensure fair resource allocation across connected clients.
• Interactive Chat & Commands: Real-time message broadcasting and server metrics tracking (/ping, stats).
• Robust Error Handling: Reusable wrapper functions with descriptive diagnostics.

Project Structure

.
├── include/
│   ├── utils.h          # Socket wrapper & non-blocking declarations
│   └── server_core.h    # Protocol, thread pool, and rate limiter definitions
├── src/
│   ├── client.cpp       # Interactive TCP client
│   ├── server.cpp       # Multi-threaded epoll server
│   └── utils.cpp        # Wrapper & fcntl implementations
├── build/               # Object files
├── bin/                 # Compiled executables
├── Makefile
├── LICENSE
└── README.md

Building

Clone the repository:

git clone https://github.com/Jx-ls/tcp-server-client.git
cd tcp-server-client

Compile the project:

make

This generates the executables:

bin/server
bin/client

To clean generated files:

make clean

Running

Start the server

./bin/server 8080

Server output:

[Server] Listening on port 8080...

Start the client

./bin/client 127.0.0.1 8080

Example client output:

Connected to server successfully!
Type messages or '/ping' to test latency.
> Hello from client!
> /ping
PONG

Technologies Used

• C++20
• POSIX Socket API
• Linux System Calls (epoll, fcntl, socket)
• C++ Multithreading (std::thread, std::mutex, std::condition_variable)
• GNU Make
• g++

Concepts Demonstrated

• TCP/IP networking and client-server architecture
• High-performance I/O multiplexing with edge-triggered (EPOLLET) epoll
• Non-blocking socket configuration using fcntl()
• Producer-Consumer thread pool concurrency patterns
• Token-bucket rate limiting algorithms
• Custom binary packet framing and safe buffer serialization
• Network byte order (htonl, htons) and IP conversion (inet_pton)

Build Requirements

• Linux
• g++ (C++20 compatible)
• GNU Make

License

This project is licensed under the MIT License. See the LICENSE file for details.