socks.py

# Save as proxy2.py on your LOCAL machine
import socket
import threading
from socketserver import ThreadingMixIn, TCPServer, StreamRequestHandler

class SOCKSProxyHandler(StreamRequestHandler):
    def handle(self):
        print("New connection")
        # Read initial byte to determine SOCKS version
        version = self.connection.recv(1)
        print(f"Received version: {version}")

        if version == b'\x04':  # SOCKS4
            self.handle_socks4()
        elif version == b'\x05':  # SOCKS5
            self.handle_socks5()
        else:
            print("Unsupported SOCKS version")
            return

    def handle_socks4(self):
        print("Handling SOCKS4")
        cmd = self.connection.recv(1)  # CONNECT (0x01)
        if cmd != b'\x01':
            print("SOCKS4: Only CONNECT supported")
            return
        port = int.from_bytes(self.connection.recv(2), 'big')
        addr = socket.inet_ntoa(self.connection.recv(4))
        user_id = b''
        while True:  # Read until null-terminated user ID
            byte = self.connection.recv(1)
            if byte == b'\x00':
                break
            user_id += byte
        print(f"SOCKS4: Connecting to {addr}:{port}, user_id={user_id.decode('ascii')}")
        
        remote = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        try:
            remote.connect((addr, port))
            # SOCKS4 reply: success (0x5A)
            self.connection.send(b'\x00\x5A' + self.connection.recv(2) + socket.inet_aton('0.0.0.0'))
            self.forward_data(remote)
        except Exception as e:
            print(f"SOCKS4 error: {e}")
            self.connection.send(b'\x00\x5B' + self.connection.recv(2) + socket.inet_aton('0.0.0.0'))  # Failed
        finally:
            remote.close()

    def handle_socks5(self):
        print("Handling SOCKS5")
        # SOCKS5 greeting
        nmethods = self.connection.recv(1)[0]
        methods = self.connection.recv(nmethods)
        print(f"Auth methods: {methods}")
        self.connection.send(b'\x05\x00')  # No authentication
        
        # SOCKS5 request
        request = self.connection.recv(4)
        print(f"Received request: {request}")
        if len(request) < 4 or request[0] != 5 or request[1] != 1:
            print("Invalid SOCKS5 request")
            self.connection.send(b'\x05\x07\x00\x01')  # Command not supported
            return
        
        atyp = request[3]
        if atyp == 1:  # IPv4
            dest_addr = socket.inet_ntoa(self.connection.recv(4))
        elif atyp == 3:  # Domain name
            addr_len = self.connection.recv(1)[0]
            dest_addr = self.connection.recv(addr_len).decode('utf-8')
        else:
            print("Unsupported address type")
            self.connection.send(b'\x05\x08\x00\x01')
            return
        
        dest_port = int.from_bytes(self.connection.recv(2), 'big')
        print(f"SOCKS5: Connecting to {dest_addr}:{dest_port}")
        
        remote = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        try:
            remote.connect((dest_addr, dest_port))
            self.connection.send(b'\x05\x00\x00\x01\x00\x00\x00\x00\x00\x00')  # Success
            self.forward_data(remote)
        except Exception as e:
            print(f"SOCKS5 error: {e}")
            self.connection.send(b'\x05\x04\x00\x01')  # Host unreachable
        finally:
            remote.close()

    def forward_data(self, remote):
        print("Forwarding data")
        def forward(src, dst):
            while True:
                data = src.recv(4096)
                if not data:
                    break
                dst.send(data)
        threading.Thread(target=forward, args=(self.connection, remote)).start()
        forward(remote, self.connection)

class ThreadingTCPServer(ThreadingMixIn, TCPServer):
    pass

if __name__ == "__main__":
    server = ThreadingTCPServer(('127.0.0.1', 1337), SOCKSProxyHandler)
    print("SOCKS proxy running on localhost:1337")
    server.serve_forever()