This Perl code implements a SOCKS5 proxy server that listens for incoming connections and processes them in separate threads. The server takes four input parameters: host, port, login, and password.

When a client attempts to connect to the server, the server checks if the client supports any of the available authentication methods (no authentication or login/password authentication). If a suitable method is found, the server establishes a connection with the target server and begins forwarding data between the client and the target server.

The code uses the IO::Select module for working with sockets and the threads module for creating and managing threads. It includes several functions, including:

• main: the main function that creates threads for processing incoming connections.
• replenish: a function that creates additional threads if the number of free threads is less than the specified value.
• new_client: a function that handles incoming client connections and checks if the available authentication methods are supported by the client.
• socks_auth: a function that performs login and password authentication.
• handle_client: a function that establishes a connection with the target server and forwards data between the client and the target server.

This code includes the use of the following Perl modules: IO::Select, Socket, threads, threads::shared.

To run this code, enter the following command: perl socks5.pl host port login password

Note that this code is designed for educational purposes and should not be used in production environments without proper modifications and security measures. 😊

This code is distributed under the MIT License, which allows for free use, modification, and distribution of the code as long as the original copyright notice and license are included.