chore cleanup

cmd/main.go

@@ -31,7 +31,6 @@ var (
 
 	args = new(CmdArgs)
 
-	handlerCreator  func()
 	postFlagsInitFn []func()
 
 	lwipWriter    io.Writer
@@ -41,14 +40,13 @@ var (
 
 type CmdArgs struct {
 	// Main
-	Version   *bool
-	DelayICMP *int
-	TunName   *string
-	TunAddr   *string
-	TunGw     *string
-	TunMask   *string
-	TunDns    *string
-	LogLevel  *string
+	Version  *bool
+	TunName  *string
+	TunAddr  *string
+	TunGw    *string
+	TunMask  *string
+	TunDns   *string
+	LogLevel *string
 
 	// Proxy
 	ProxyServer *string
@@ -79,7 +77,6 @@ func init() {
 	args.TunGw = flag.String("tunGw", "240.0.0.1", "TUN interface gateway")
 	args.TunMask = flag.String("tunMask", "255.255.255.0", "TUN interface netmask, it should be a prefix length (a number) for IPv6 address")
 	args.TunDns = flag.String("tunDns", "1.1.1.1", "DNS resolvers for TUN interface (Windows Only)")
-	args.DelayICMP = flag.Int("delayICMP", 1, "Delay ICMP packets for a short period of time, in milliseconds")
 
 	// Proxy
 	args.ProxyServer = flag.String("proxyServer", "", "Proxy server address")
@@ -127,13 +124,9 @@ func main() {
 	}
 
 	// Setup TCP/IP stack.
-	lwipWriter = core.NewLWIPStack().(io.Writer)
-
-	// Wrap a writer to delay ICMP packets if delay time is not zero.
-	if *args.DelayICMP > 0 {
-		log.Infof("ICMP packets will be delayed for %dms", *args.DelayICMP)
-		lwipWriter = filter.NewICMPFilter(lwipWriter, *args.DelayICMP).(io.Writer)
-	}
+	// Wrap a writer to delay ICMP packets.
+	w := core.NewLWIPStack().(io.Writer)
+	lwipWriter = filter.NewICMPFilter(w).(io.Writer)
 
 	// Register TCP and UDP handlers to handle accepted connections.
 	proxyAddr, err := net.ResolveTCPAddr("tcp", *args.ProxyServer)
@@ -153,8 +146,7 @@ func main() {
 
 	// Copy packets from tun device to lwip stack, it's the main loop.
 	go func() {
-		_, err := io.CopyBuffer(lwipWriter, tunDev, make([]byte, MTU))
-		if err != nil {
+		if _, err := io.CopyBuffer(lwipWriter, tunDev, make([]byte, MTU)); err != nil {
 			log.Fatalf("copying data failed: %v", err)
 		}
 	}()

common/stats/session/session.go

@@ -34,7 +34,7 @@ func NewSimpleSessionStater() stats.SessionStater {
 	return &simpleSessionStater{}
 }
 
-func (s *simpleSessionStater) Start() error {
+func (s *simpleSessionStater) Start() {
 	log.Debugf("Start session stater")
 	sessionStatsHandler := func(resp http.ResponseWriter, req *http.Request) {
 		// Make a snapshot.
@@ -97,12 +97,11 @@ func (s *simpleSessionStater) Start() error {
 	mux.HandleFunc(StatsPath, sessionStatsHandler)
 	s.server = &http.Server{Addr: StatsAddr, Handler: mux}
 	go s.server.ListenAndServe()
-	return nil
 }
 
-func (s *simpleSessionStater) Stop() error {
+func (s *simpleSessionStater) Stop() {
 	log.Debugf("Stop session stater")
-	return s.server.Close()
+	s.server.Close()
 }
 
 func (s *simpleSessionStater) AddSession(key interface{}, session *stats.Session) {

common/stats/stats.go

@@ -8,8 +8,8 @@ import (
 )
 
 type SessionStater interface {
-	Start() error
-	Stop() error
+	Start()
+	Stop()
 	AddSession(key interface{}, session *Session)
 	GetSession(key interface{}) *Session
 	RemoveSession(key interface{})

filter/filter.go

@@ -4,7 +4,7 @@ import (
 	"io"
 )
 
-// Filter is used for filtering IP packets comming from TUN.
+// Filter is used for filtering IP packets coming from TUN.
 type Filter interface {
 	io.Writer
 }

filter/icmp.go

@@ -2,7 +2,6 @@ package filter
 
 import (
 	"io"
-	"time"
 
 	"github.com/xjasonlyu/tun2socks/common/log"
 	"github.com/xjasonlyu/tun2socks/common/packet"
@@ -10,26 +9,23 @@ import (
 
 type icmpFilter struct {
 	writer io.Writer
-	delay  int
 }
 
-func NewICMPFilter(w io.Writer, delay int) Filter {
-	return &icmpFilter{writer: w, delay: delay}
+func NewICMPFilter(w io.Writer) Filter {
+	return &icmpFilter{writer: w}
 }
 
-func (w *icmpFilter) Write(buf []byte) (int, error) {
-	if uint8(buf[9]) == packet.PROTOCOL_ICMP {
+func (f *icmpFilter) Write(buf []byte) (int, error) {
+	if buf[9] == packet.PROTOCOL_ICMP {
 		payload := make([]byte, len(buf))
 		copy(payload, buf)
 		go func(data []byte) {
-			time.Sleep(time.Duration(w.delay) * time.Millisecond)
-			_, err := w.writer.Write(data)
-			if err != nil {
+			if _, err := f.writer.Write(data); err != nil {
 				log.Fatalf("failed to input data to the stack: %v", err)
 			}
 		}(payload)
 		return len(buf), nil
 	} else {
-		return w.writer.Write(buf)
+		return f.writer.Write(buf)
 	}
 }

proxy/udp.go

@@ -42,6 +42,9 @@ func NewUDPHandler(proxyHost string, proxyPort uint16, timeout time.Duration, fa
 }
 
 func (h *udpHandler) handleTCP(conn core.UDPConn, c net.Conn) {
+	// keep tcp connection alive
+	tcpKeepAlive(c)
+
 	for {
 		// clear timeout settings
 		c.SetDeadline(time.Time{})
@@ -74,7 +77,7 @@ func (h *udpHandler) fetchUDPInput(conn core.UDPConn, input net.PacketConn) {
 			return
 		}
 
-		if n < 4 {
+		if n < 5 {
 			log.Warnf("short udp packet length: %d", n)
 			return
 		}
@@ -85,7 +88,7 @@ func (h *udpHandler) fetchUDPInput(conn core.UDPConn, input net.PacketConn) {
 			return
 		}
 
-		if _, err := conn.WriteFrom(buf[int(3+len(addr)):n], resolvedAddr); err != nil {
+		if _, err := conn.WriteFrom(buf[3+len(addr):n], resolvedAddr); err != nil {
 			log.Warnf("failed to write UDP data: %v", err)
 			return
 		}
@@ -94,7 +97,6 @@ func (h *udpHandler) fetchUDPInput(conn core.UDPConn, input net.PacketConn) {
 
 func (h *udpHandler) Connect(conn core.UDPConn, target *net.UDPAddr) error {
 	if target == nil {
-		// return h.connectInternal(conn, "")
 		log.Warnf("UDP target is invalid: %s", conn.LocalAddr().String())
 		return errors.New("UDP target is invalid")
 	}