func serverHandler(f base.ServerFactory, conn net.Conn, info *pt.ServerInfo) {
	defer conn.Close()
	termMon.onHandlerStart()
	defer termMon.onHandlerFinish()

	name := f.Transport().Name()
	addrStr := log.ElideAddr(conn.RemoteAddr().String())
	log.Infof("%s(%s) - new connection", name, addrStr)

	// Instantiate the server transport method and handshake.
	remote, err := f.WrapConn(conn)
	if err != nil {
		log.Warnf("%s(%s) - handshake failed: %s", name, addrStr, log.ElideError(err))
		return
	}

	// Connect to the orport.
	orConn, err := pt.DialOr(info, conn.RemoteAddr().String(), name)
	if err != nil {
		log.Errorf("%s(%s) - failed to connect to ORPort: %s", name, addrStr, log.ElideError(err))
		return
	}
	defer orConn.Close()

	if err = copyLoop(orConn, remote); err != nil {
		log.Warnf("%s(%s) - closed connection: %s", name, addrStr, log.ElideError(err))
	} else {
		log.Infof("%s(%s) - closed connection", name, addrStr)
	}

	return
}

func clientHandler(f base.ClientFactory, conn net.Conn, proxyURI *url.URL) {
	defer conn.Close()
	termMon.onHandlerStart()
	defer termMon.onHandlerFinish()

	name := f.Transport().Name()

	// Read the client's SOCKS handshake.
	socksReq, err := socks5.Handshake(conn)
	if err != nil {
		log.Errorf("%s - client failed socks handshake: %s", name, err)
		return
	}
	addrStr := log.ElideAddr(socksReq.Target)

	// Deal with arguments.
	args, err := f.ParseArgs(&socksReq.Args)
	if err != nil {
		log.Errorf("%s(%s) - invalid arguments: %s", name, addrStr, err)
		socksReq.Reply(socks5.ReplyGeneralFailure)
		return
	}

	// Obtain the proxy dialer if any, and create the outgoing TCP connection.
	dialFn := proxy.Direct.Dial
	if proxyURI != nil {
		dialer, err := proxy.FromURL(proxyURI, proxy.Direct)
		if err != nil {
			// This should basically never happen, since config protocol
			// verifies this.
			log.Errorf("%s(%s) - failed to obtain proxy dialer: %s", name, addrStr, log.ElideError(err))
			socksReq.Reply(socks5.ReplyGeneralFailure)
			return
		}
		dialFn = dialer.Dial
	}
	remote, err := f.Dial("tcp", socksReq.Target, dialFn, args)
	if err != nil {
		log.Errorf("%s(%s) - outgoing connection failed: %s", name, addrStr, log.ElideError(err))
		socksReq.Reply(socks5.ErrorToReplyCode(err))
		return
	}
	defer remote.Close()
	err = socksReq.Reply(socks5.ReplySucceeded)
	if err != nil {
		log.Errorf("%s(%s) - SOCKS reply failed: %s", name, addrStr, log.ElideError(err))
		return
	}

	if err = copyLoop(conn, remote); err != nil {
		log.Warnf("%s(%s) - closed connection: %s", name, addrStr, log.ElideError(err))
	} else {
		log.Infof("%s(%s) - closed connection", name, addrStr)
	}

	return
}

func clientHandler(f base.ClientFactory, conn net.Conn, proxyURI *url.URL, linkInfo LinkInfo) {
	defer conn.Close()
	termMon.onHandlerStart()
	defer termMon.onHandlerFinish()

	name := f.Transport().Name()

	fakeReq, err := parseClientParameters(strings.Replace(linkInfo.PtArgs, ",", ";", -1))

	if err != nil {
		log.Errorf("%s - client failed socks handshake: %s", name, err)
		return
	}
	addrStr := log.ElideAddr(linkInfo.ServerAddr)

	// Deal with arguments.
	args, err := f.ParseArgs(&fakeReq)
	if err != nil {
		log.Errorf("%s(%s) - invalid arguments: %s", name, addrStr, err)
		return
	}

	// Obtain the proxy dialer if any, and create the outgoing TCP connection.
	dialFn := proxy.Direct.Dial
	if proxyURI != nil {
		dialer, err := proxy.FromURL(proxyURI, proxy.Direct)
		if err != nil {
			// This should basically never happen, since config protocol
			// verifies this.
			log.Errorf("%s(%s) - failed to obtain proxy dialer: %s", name, addrStr, log.ElideError(err))
			return
		}
		dialFn = dialer.Dial
	}

	remote, er := f.Dial("tcp", linkInfo.ServerAddr, dialFn, args)

	if er != nil {
		log.Errorf("%s(%s) - outgoing connection failed: %s", name, addrStr, log.ElideError(er))
		return
	}
	defer remote.Close()

	if err = copyLoop(conn, remote); err != nil {
		log.Warnf("%s(%s) - closed connection: %s", name, addrStr, log.ElideError(err))
	} else {
		log.Infof("%s(%s) - closed connection", name, addrStr)
	}

	return
}

func clientSetup() (launched bool, listeners []net.Listener) {
	ptClientInfo, err := pt.ClientSetup(transports.Transports())
	if err != nil {
		golog.Fatal(err)
	}

	ptClientProxy, err := ptGetProxy()
	if err != nil {
		golog.Fatal(err)
	} else if ptClientProxy != nil {
		ptProxyDone()
	}

	// Launch each of the client listeners.
	for _, name := range ptClientInfo.MethodNames {
		t := transports.Get(name)
		if t == nil {
			pt.CmethodError(name, "no such transport is supported")
			continue
		}

		f, err := t.ClientFactory(stateDir)
		if err != nil {
			pt.CmethodError(name, "failed to get ClientFactory")
			continue
		}

		ln, err := net.Listen("tcp", socksAddr)
		if err != nil {
			pt.CmethodError(name, err.Error())
			continue
		}

		go clientAcceptLoop(f, ln, ptClientProxy)
		pt.Cmethod(name, socks5.Version(), ln.Addr())

		log.Infof("%s - registered listener: %s", name, ln.Addr())

		listeners = append(listeners, ln)
		launched = true
	}
	pt.CmethodsDone()

	return
}

func serverSetup() (launched bool, listeners []net.Listener) {
	ptServerInfo, err := pt.ServerSetup(transports.Transports())
	if err != nil {
		golog.Fatal(err)
	}

	for _, bindaddr := range ptServerInfo.Bindaddrs {
		name := bindaddr.MethodName
		t := transports.Get(name)
		if t == nil {
			pt.SmethodError(name, "no such transport is supported")
			continue
		}

		f, err := t.ServerFactory(stateDir, &bindaddr.Options)
		if err != nil {
			pt.SmethodError(name, err.Error())
			continue
		}

		ln, err := net.ListenTCP("tcp", bindaddr.Addr)
		if err != nil {
			pt.SmethodError(name, err.Error())
			continue
		}

		go serverAcceptLoop(f, ln, &ptServerInfo)
		if args := f.Args(); args != nil {
			pt.SmethodArgs(name, ln.Addr(), *args)
		} else {
			pt.SmethodArgs(name, ln.Addr(), nil)
		}

		log.Infof("%s - registered listener: %s", name, log.ElideAddr(ln.Addr().String()))

		listeners = append(listeners, ln)
		launched = true
	}
	pt.SmethodsDone()

	return
}

func clientSetup() (launched bool, listeners []net.Listener) {
	ptClientInfo, err := pt.ClientSetup(transports.Transports())
	if err != nil {
		golog.Fatal(err)
	}

	ptClientProxy, err := ptGetProxy()
	if err != nil {
		golog.Fatal(err)
	} else if ptClientProxy != nil {
		ptProxyDone()
	}

	configFile := os.Getenv("TCP_PROXY_CONFIG_FILE")

	bytes, er := ioutil.ReadFile(configFile)

	if er != nil {
		fmt.Println("unable to read config file ", configFile)
		golog.Fatal(err)
	}

	fmt.Println("parse config file ", configFile)
	config := parseConfig(bytes)

	// Launch each of the client listeners.
	for _, name := range ptClientInfo.MethodNames {
		t := transports.Get(name)
		if t == nil {
			pt.CmethodError(name, "no such transport is supported")
			continue
		}

		links, has := config[name]

		if !has {
			continue
		}

		f, err := t.ClientFactory(stateDir)
		if err != nil {
			pt.CmethodError(name, "failed to get ClientFactory")
			continue
		}

		for _, link := range links {

			fmt.Println("create tcp proxy ", name, link.ListenAddr, link.ServerAddr, link.PtArgs)
			ln, er := net.Listen("tcp", link.ListenAddr)
			if er != nil {
				pt.CmethodError(name, er.Error())
				continue
			}

			go clientAcceptLoop(f, ln, ptClientProxy, link)
			pt.Cmethod(name, "tcp", ln.Addr())

			log.Infof("%s - registered listener: %s", name, ln.Addr())

			listeners = append(listeners, ln)
			launched = true
		}
	}

	pt.CmethodsDone()

	return
}

func main() {
	// Initialize the termination state monitor as soon as possible.
	termMon = newTermMonitor()

	// Handle the command line arguments.
	_, execName := path.Split(os.Args[0])
	showVer := flag.Bool("version", false, "Print version and exit")
	logLevelStr := flag.String("logLevel", "ERROR", "Log level (ERROR/WARN/INFO/DEBUG)")
	enableLogging := flag.Bool("enableLogging", false, "Log to TOR_PT_STATE_LOCATION/"+obfs4proxyLogFile)
	unsafeLogging := flag.Bool("unsafeLogging", false, "Disable the address scrubber")
	flag.Parse()

	if *showVer {
		fmt.Printf("%s\n", getVersion())
		os.Exit(0)
	}
	if err := log.SetLogLevel(*logLevelStr); err != nil {
		golog.Fatalf("[ERROR]: %s - failed to set log level: %s", execName, err)
	}

	// Determine if this is a client or server, initialize the common state.
	var ptListeners []net.Listener
	launched := false
	isClient, err := ptIsClient()
	if err != nil {
		golog.Fatalf("[ERROR]: %s - must be run as a managed transport", execName)
	}
	if stateDir, err = pt.MakeStateDir(); err != nil {
		golog.Fatalf("[ERROR]: %s - No state directory: %s", execName, err)
	}
	if err = log.Init(*enableLogging, path.Join(stateDir, obfs4proxyLogFile), *unsafeLogging); err != nil {
		golog.Fatalf("[ERROR]: %s - failed to initialize logging", execName)
	}
	if err = transports.Init(); err != nil {
		log.Errorf("%s - failed to initialize transports: %s", execName, err)
		os.Exit(-1)
	}

	log.Noticef("%s - launched", getVersion())

	// Do the managed pluggable transport protocol configuration.
	if isClient {
		log.Infof("%s - initializing client transport listeners", execName)
		launched, ptListeners = clientSetup()
	} else {
		log.Infof("%s - initializing server transport listeners", execName)
		launched, ptListeners = serverSetup()
	}
	if !launched {
		// Initialization failed, the client or server setup routines should
		// have logged, so just exit here.
		os.Exit(-1)
	}

	log.Infof("%s - accepting connections", execName)
	defer func() {
		log.Noticef("%s - terminated", execName)
	}()

	// At this point, the pt config protocol is finished, and incoming
	// connections will be processed.  Wait till the parent dies
	// (immediate exit), a SIGTERM is received (immediate exit),
	// or a SIGINT is received.
	if sig := termMon.wait(false); sig == syscall.SIGTERM {
		return
	}

	// Ok, it was the first SIGINT, close all listeners, and wait till,
	// the parent dies, all the current connections are closed, or either
	// a SIGINT/SIGTERM is received, and exit.
	for _, ln := range ptListeners {
		ln.Close()
	}
	termMon.wait(true)
}

func clientHandler(f base.ClientFactory, conn *pt.SocksConn, proxyURI *url.URL) {
	defer conn.Close()
	termMon.onHandlerStart()
	defer termMon.onHandlerFinish()

	name := f.Transport().Name()
	addrStr := log.ElideAddr(conn.Req.Target)
	log.Infof("%s(%s) - new connection", name, addrStr)

	// Deal with arguments.
	args, err := f.ParseArgs(&conn.Req.Args)
	if err != nil {
		log.Errorf("%s(%s) - invalid arguments: %s", name, addrStr, err)
		conn.Reject()
		return
	}

	// Obtain the proxy dialer if any, and create the outgoing TCP connection.
	var dialFn DialFn
	if proxyURI == nil {
		dialFn = proxy.Direct.Dial
	} else {
		// This is unlikely to happen as the proxy protocol is verified during
		// the configuration phase.
		dialer, err := proxy.FromURL(proxyURI, proxy.Direct)
		if err != nil {
			log.Errorf("%s(%s) - failed to obtain proxy dialer: %s", name, addrStr, log.ElideError(err))
			conn.Reject()
			return
		}
		dialFn = dialer.Dial
	}
	remoteConn, err := dialFn("tcp", conn.Req.Target) // XXX: Allow UDP?
	if err != nil {
		log.Errorf("%s(%s) - outgoing connection failed: %s", name, addrStr, log.ElideError(err))
		conn.Reject()
		return
	}
	defer remoteConn.Close()

	// Instantiate the client transport method, handshake, and start pushing
	// bytes back and forth.
	remote, err := f.WrapConn(remoteConn, args)
	if err != nil {
		log.Errorf("%s(%s) - handshake failed: %s", name, addrStr, log.ElideError(err))
		conn.Reject()
		return
	}
	err = conn.Grant(remoteConn.RemoteAddr().(*net.TCPAddr))
	if err != nil {
		log.Errorf("%s(%s) - SOCKS grant failed: %s", name, addrStr, log.ElideError(err))
		return
	}

	if err = copyLoop(conn, remote); err != nil {
		log.Warnf("%s(%s) - closed connection: %s", name, addrStr, log.ElideError(err))
	} else {
		log.Infof("%s(%s) - closed connection", name, addrStr)
	}

	return
}