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))
+}