Feature: add TCP TPROXY support (#1049)

proxy/redir/tproxy.go

@@ -0,0 +1,71 @@
+package redir
+
+import (
+	"net"
+
+	"github.com/Dreamacro/clash/adapters/inbound"
+	"github.com/Dreamacro/clash/component/socks5"
+	C "github.com/Dreamacro/clash/constant"
+	"github.com/Dreamacro/clash/log"
+	"github.com/Dreamacro/clash/tunnel"
+)
+
+type TProxyListener struct {
+	net.Listener
+	address string
+	closed  bool
+}
+
+func NewTProxy(addr string) (*TProxyListener, error) {
+	l, err := net.Listen("tcp", addr)
+	if err != nil {
+		return nil, err
+	}
+
+	tl := l.(*net.TCPListener)
+	rc, err := tl.SyscallConn()
+	if err != nil {
+		return nil, err
+	}
+
+	err = setsockopt(rc, addr)
+	if err != nil {
+		return nil, err
+	}
+
+	rl := &TProxyListener{
+		Listener: l,
+		address:  addr,
+	}
+
+	go func() {
+		log.Infoln("TProxy server listening at: %s", addr)
+		for {
+			c, err := l.Accept()
+			if err != nil {
+				if rl.closed {
+					break
+				}
+				continue
+			}
+			go rl.handleRedir(c)
+		}
+	}()
+
+	return rl, nil
+}
+
+func (l *TProxyListener) Close() {
+	l.closed = true
+	l.Listener.Close()
+}
+
+func (l *TProxyListener) Address() string {
+	return l.address
+}
+
+func (l *TProxyListener) handleRedir(conn net.Conn) {
+	target := socks5.ParseAddrToSocksAddr(conn.LocalAddr())
+	conn.(*net.TCPConn).SetKeepAlive(true)
+	tunnel.Add(inbound.NewSocket(target, conn, C.TPROXY))
+}

proxy/redir/tproxy_linux.go

@@ -0,0 +1,40 @@
+// +build linux
+
+package redir
+
+import (
+	"net"
+	"syscall"
+)
+
+func setsockopt(rc syscall.RawConn, addr string) error {
+	isIPv6 := true
+	host, _, err := net.SplitHostPort(addr)
+	if err != nil {
+		return err
+	}
+	ip := net.ParseIP(host)
+	if ip != nil && ip.To4() != nil {
+		isIPv6 = false
+	}
+
+	rc.Control(func(fd uintptr) {
+		err = syscall.SetsockoptInt(int(fd), syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1)
+
+		if err == nil {
+			err = syscall.SetsockoptInt(int(fd), syscall.SOL_IP, syscall.IP_TRANSPARENT, 1)
+		}
+		if err == nil && isIPv6 {
+			err = syscall.SetsockoptInt(int(fd), syscall.SOL_IPV6, IPV6_TRANSPARENT, 1)
+		}
+
+		if err == nil {
+			err = syscall.SetsockoptInt(int(fd), syscall.SOL_IP, syscall.IP_RECVORIGDSTADDR, 1)
+		}
+		if err == nil && isIPv6 {
+			err = syscall.SetsockoptInt(int(fd), syscall.SOL_IPV6, IPV6_RECVORIGDSTADDR, 1)
+		}
+	})
+
+	return err
+}

proxy/redir/tproxy_other.go

@@ -0,0 +1,12 @@
+// +build !linux
+
+package redir
+
+import (
+	"errors"
+	"syscall"
+)
+
+func setsockopt(rc syscall.RawConn, addr string) error {
+	return errors.New("Not supported on current platform")
+}

proxy/redir/udp.go

@@ -26,7 +26,12 @@ func NewRedirUDPProxy(addr string) (*RedirUDPListener, error) {
 
 	c := l.(*net.UDPConn)
 
-	err = setsockopt(c, addr)
+	rc, err := c.SyscallConn()
+	if err != nil {
+		return nil, err
+	}
+
+	err = setsockopt(rc, addr)
 	if err != nil {
 		return nil, err
 	}

proxy/redir/udp_linux.go

@@ -14,43 +14,6 @@ const (
 	IPV6_RECVORIGDSTADDR = 0x4a
 )
 
-func setsockopt(c *net.UDPConn, addr string) error {
-	isIPv6 := true
-	host, _, err := net.SplitHostPort(addr)
-	if err != nil {
-		return err
-	}
-	ip := net.ParseIP(host)
-	if ip != nil && ip.To4() != nil {
-		isIPv6 = false
-	}
-
-	rc, err := c.SyscallConn()
-	if err != nil {
-		return err
-	}
-
-	rc.Control(func(fd uintptr) {
-		err = syscall.SetsockoptInt(int(fd), syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1)
-
-		if err == nil {
-			err = syscall.SetsockoptInt(int(fd), syscall.SOL_IP, syscall.IP_TRANSPARENT, 1)
-		}
-		if err == nil && isIPv6 {
-			err = syscall.SetsockoptInt(int(fd), syscall.SOL_IPV6, IPV6_TRANSPARENT, 1)
-		}
-
-		if err == nil {
-			err = syscall.SetsockoptInt(int(fd), syscall.SOL_IP, syscall.IP_RECVORIGDSTADDR, 1)
-		}
-		if err == nil && isIPv6 {
-			err = syscall.SetsockoptInt(int(fd), syscall.SOL_IPV6, IPV6_RECVORIGDSTADDR, 1)
-		}
-	})
-
-	return err
-}
-
 func getOrigDst(oob []byte, oobn int) (*net.UDPAddr, error) {
 	msgs, err := syscall.ParseSocketControlMessage(oob[:oobn])
 	if err != nil {

proxy/redir/udp_other.go

@@ -7,10 +7,6 @@ import (
 	"net"
 )
 
-func setsockopt(c *net.UDPConn, addr string) error {
-	return errors.New("UDP redir not supported on current platform")
-}
-
 func getOrigDst(oob []byte, oobn int) (*net.UDPAddr, error) {
 	return nil, errors.New("UDP redir not supported on current platform")
 }