func run(port, password, limit string) {
	ln, err := net.Listen("tcp", ":"+port)
	if err != nil {
		log.Printf("error listening port %v: %v\n", port, err)
		return
	}
	passwdManager.add(port, password, ln)
	var cipher *ss.Cipher
	log.Printf("server listening port %v with limit %v...\n", port, limit)
	for {
		if isOverFlow(port) {
			//fmt.Println(port, "流量超了!!")
			continue
		}
		conn, err := ln.Accept()
		if err != nil {
			// listener maybe closed to update password
			debug.Printf("accept error: %v\n", err)
			return
		}
		// Creating cipher upon first connection.
		if cipher == nil {
			log.Println("creating cipher for port:", port)
			cipher, err = ss.NewCipher(config.Method, password)

			if err != nil {
				log.Printf("Error generating cipher for port: %s %v\n", port, err)
				conn.Close()
				continue
			}
		}
		go handleConnection(ss.NewConn(conn, cipher.Copy()), port)
	}
}
func runUDP(port, password, limit string) {
	var cipher *ss.Cipher
	port_i, _ := strconv.Atoi(port)
	log.Printf("listening udp port %v\n", port)
	conn, err := net.ListenUDP("udp", &net.UDPAddr{
		IP:   net.IPv6zero,
		Port: port_i,
	})
	passwdManager.addUDP(port, password, conn)
	if err != nil {
		log.Printf("error listening udp port %v: %v\n", port, err)
		return
	}
	defer conn.Close()
	cipher, err = ss.NewCipher(config.Method, password)
	if err != nil {
		log.Printf("Error generating cipher for udp port: %s %v\n", port, err)
		conn.Close()
	}
	UDPConn := ss.NewUDPConn(conn, cipher.Copy())
	for {
		UDPConn.ReadAndHandleUDPReq()
	}
}