import socket
import threading


LISTEN_HOST = "127.0.0.1"
LISTEN_PORT = 18007
TARGET_HOST = "192.168.41.184"
TARGET_PORT = 8007


def pipe(src: socket.socket, dst: socket.socket) -> None:
    try:
        while True:
            data = src.recv(65536)
            if not data:
                break
            dst.sendall(data)
    except OSError:
        pass
    finally:
        for sock in (src, dst):
            try:
                sock.shutdown(socket.SHUT_RDWR)
            except OSError:
                pass
            try:
                sock.close()
            except OSError:
                pass


def handle_client(client: socket.socket) -> None:
    upstream = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    upstream.connect((TARGET_HOST, TARGET_PORT))
    threading.Thread(target=pipe, args=(client, upstream), daemon=True).start()
    threading.Thread(target=pipe, args=(upstream, client), daemon=True).start()


def main() -> None:
    server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    server.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    server.bind((LISTEN_HOST, LISTEN_PORT))
    server.listen()
    while True:
        client, _ = server.accept()
        threading.Thread(target=handle_client, args=(client,), daemon=True).start()


if __name__ == "__main__":
    main()