kcp: add fake TCP support

cmd/gost/route.go

@@ -139,6 +139,13 @@ func parseChainNode(ns string) (nodes []gost.Node, err error) {
 		if err != nil {
 			return nil, err
 		}
+		if config == nil {
+			conf := gost.DefaultKCPConfig
+			if node.GetBool("tcp") {
+				conf.TCP = true
+			}
+			config = &conf
+		}
 		tr = gost.KCPTransporter(config)
 	case "ssh":
 		if node.Protocol == "direct" || node.Protocol == "remote" {
@@ -322,6 +329,13 @@ func (r *route) GenRouters() ([]router, error) {
 			if er != nil {
 				return nil, er
 			}
+			if config == nil {
+				conf := gost.DefaultKCPConfig
+				if node.GetBool("tcp") {
+					conf.TCP = true
+				}
+				config = &conf
+			}
 			ln, err = gost.KCPListener(node.Addr, config)
 		case "ssh":
 			config := &gost.SSHConfig{

ftcp.go

@@ -99,11 +99,7 @@ func (l *fakeTCPListener) listenLoop() {
 
 		conn, ok := l.connMap.Get(raddr.String())
 		if !ok {
-			cc := &fakeTCPConn{
-				raddr:      raddr,
-				PacketConn: l.ln,
-			}
-			conn = newUDPServerConn(cc, raddr, l.config.TTL, l.config.QueueSize)
+			conn = newUDPServerConn(l.ln, raddr, l.config.TTL, l.config.QueueSize)
 			conn.onClose = func() {
 				l.connMap.Delete(raddr.String())
 				log.Logf("[ftcp] %s closed (%d)", raddr, l.connMap.Size())
@@ -157,7 +153,6 @@ func (l *fakeTCPListener) Close() error {
 }
 
 type fakeTCPConn struct {
-	mss   int
 	raddr net.Addr
 	net.PacketConn
 }
@@ -171,33 +166,6 @@ func (c *fakeTCPConn) Write(b []byte) (n int, err error) {
 	return c.WriteTo(b, c.raddr)
 }
 
-func (c *fakeTCPConn) WriteTo(b []byte, addr net.Addr) (n int, err error) {
-	mss := c.mss
-	if mss <= 0 {
-		mss = 1460
-	}
-
-	for {
-		if len(b) == 0 {
-			break
-		}
-		var nn int
-		if len(b) <= mss {
-			nn, err = c.PacketConn.WriteTo(b, addr)
-			n += nn
-			break
-		}
-		nn, err = c.PacketConn.WriteTo(b[:mss], addr)
-		n += nn
-		if err != nil {
-			break
-		}
-		b = b[mss:]
-	}
-
-	return
-}
-
 func (c *fakeTCPConn) RemoteAddr() net.Addr {
 	return c.raddr
 }

kcp.go

@@ -15,6 +15,7 @@ import (
 
 	"github.com/go-log/log"
 	"github.com/klauspost/compress/snappy"
+	"github.com/xtaci/tcpraw"
 	"gopkg.in/xtaci/kcp-go.v4"
 	"gopkg.in/xtaci/smux.v1"
 )
@@ -46,6 +47,7 @@ type KCPConfig struct {
 	SnmpLog      string `json:"snmplog"`
 	SnmpPeriod   int    `json:"snmpperiod"`
 	Signal       bool   `json:"signal"` // Signal enables the signal SIGUSR1 feature.
+	TCP          bool   `json:"tcp"`
 }
 
 // Init initializes the KCP config.
@@ -85,6 +87,7 @@ var (
 		SnmpLog:      "",
 		SnmpPeriod:   60,
 		Signal:       false,
+		TCP:          false,
 	}
 )
 
@@ -129,13 +132,24 @@ func (tr *kcpTransporter) Dial(addr string, options ...DialOption) (conn net.Con
 		ok = false
 	}
 	if !ok {
-		timeout := opts.Timeout
-		if timeout <= 0 {
-			timeout = DialTimeout
-		}
-		conn, err = net.DialTimeout("udp", addr, timeout)
+		raddr, err := net.ResolveUDPAddr("udp", addr)
 		if err != nil {
-			return
+			return nil, err
+		}
+		if tr.config.TCP {
+			pc, err := tcpraw.Dial("tcp", addr)
+			if err != nil {
+				return nil, err
+			}
+			conn = &fakeTCPConn{
+				raddr:      raddr,
+				PacketConn: pc,
+			}
+		} else {
+			conn, err = net.ListenUDP("udp", nil)
+			if err != nil {
+				return nil, err
+			}
 		}
 		session = &muxSession{conn: conn}
 		tr.sessions[addr] = session
@@ -184,14 +198,14 @@ func (tr *kcpTransporter) Handshake(conn net.Conn, options ...HandshakeOption) (
 }
 
 func (tr *kcpTransporter) initSession(addr string, conn net.Conn, config *KCPConfig) (*muxSession, error) {
-	udpConn, ok := conn.(*net.UDPConn)
+	pc, ok := conn.(net.PacketConn)
 	if !ok {
 		return nil, errors.New("kcp: wrong connection type")
 	}
 
 	kcpconn, err := kcp.NewConn(addr,
 		blockCrypt(config.Key, config.Crypt, KCPSalt),
-		config.DataShard, config.ParityShard, &connectedUDPConn{udpConn})
+		config.DataShard, config.ParityShard, pc)
 	if err != nil {
 		return nil, err
 	}
@@ -203,9 +217,11 @@ func (tr *kcpTransporter) initSession(addr string, conn net.Conn, config *KCPCon
 	kcpconn.SetMtu(config.MTU)
 	kcpconn.SetACKNoDelay(config.AckNodelay)
 
-	// if err := kcpconn.SetDSCP(config.DSCP); err != nil {
-	// 	log.Log("[kcp]", err)
-	// }
+	if config.DSCP > 0 {
+		if err := kcpconn.SetDSCP(config.DSCP); err != nil {
+			log.Log("[kcp]", err)
+		}
+	}
 	if err := kcpconn.SetReadBuffer(config.SockBuf); err != nil {
 		log.Log("[kcp]", err)
 	}
@@ -247,14 +263,31 @@ func KCPListener(addr string, config *KCPConfig) (Listener, error) {
 	}
 	config.Init()
 
-	ln, err := kcp.ListenWithOptions(addr,
-		blockCrypt(config.Key, config.Crypt, KCPSalt), config.DataShard, config.ParityShard)
+	var err error
+	var ln *kcp.Listener
+	if config.TCP {
+		var conn net.PacketConn
+		conn, err = tcpraw.Listen("tcp", addr)
+		if err != nil {
+			return nil, err
+		}
+		ln, err = kcp.ServeConn(
+			blockCrypt(config.Key, config.Crypt, KCPSalt), config.DataShard, config.ParityShard, conn)
+		if err != nil {
+			return nil, err
+		}
+	} else {
+		ln, err = kcp.ListenWithOptions(addr,
+			blockCrypt(config.Key, config.Crypt, KCPSalt), config.DataShard, config.ParityShard)
+	}
 	if err != nil {
 		return nil, err
 	}
-	// if err = ln.SetDSCP(config.DSCP); err != nil {
-	// 	log.Log("[kcp]", err)
-	// }
+	if config.DSCP > 0 {
+		if err = ln.SetDSCP(config.DSCP); err != nil {
+			log.Log("[kcp]", err)
+		}
+	}
 	if err = ln.SetReadBuffer(config.SockBuf); err != nil {
 		log.Log("[kcp]", err)
 	}
@@ -468,11 +501,3 @@ func (c *compStreamConn) SetReadDeadline(t time.Time) error {
 func (c *compStreamConn) SetWriteDeadline(t time.Time) error {
 	return c.conn.SetWriteDeadline(t)
 }
-
-// connectedUDPConn is a wrapper for net.UDPConn which converts WriteTo syscalls
-// to Write syscalls that are 4 times faster on some OS'es. This should only be
-// used for connections that were produced by a net.Dial* call.
-type connectedUDPConn struct{ *net.UDPConn }
-
-// WriteTo redirects all writes to the Write syscall, which is 4 times faster.
-func (c *connectedUDPConn) WriteTo(b []byte, addr net.Addr) (int, error) { return c.Write(b) }