First Commmit

protocol/redirect/tproxy.go

@@ -0,0 +1,150 @@
+package redirect
+
+import (
+	"context"
+	"net"
+	"net/netip"
+	"time"
+
+	"github.com/sagernet/sing-box/adapter"
+	"github.com/sagernet/sing-box/adapter/inbound"
+	"github.com/sagernet/sing-box/common/listener"
+	"github.com/sagernet/sing-box/common/redir"
+	C "github.com/sagernet/sing-box/constant"
+	"github.com/sagernet/sing-box/log"
+	"github.com/sagernet/sing-box/option"
+	"github.com/sagernet/sing/common"
+	"github.com/sagernet/sing/common/buf"
+	"github.com/sagernet/sing/common/control"
+	M "github.com/sagernet/sing/common/metadata"
+	N "github.com/sagernet/sing/common/network"
+	"github.com/sagernet/sing/common/udpnat2"
+)
+
+func RegisterTProxy(registry *inbound.Registry) {
+	inbound.Register[option.TProxyInboundOptions](registry, C.TypeTProxy, NewTProxy)
+}
+
+type TProxy struct {
+	inbound.Adapter
+	ctx      context.Context
+	router   adapter.Router
+	logger   log.ContextLogger
+	listener *listener.Listener
+	udpNat   *udpnat.Service
+}
+
+func NewTProxy(ctx context.Context, router adapter.Router, logger log.ContextLogger, tag string, options option.TProxyInboundOptions) (adapter.Inbound, error) {
+	tproxy := &TProxy{
+		Adapter: inbound.NewAdapter(C.TypeTProxy, tag),
+		ctx:     ctx,
+		router:  router,
+		logger:  logger,
+	}
+	var udpTimeout time.Duration
+	if options.UDPTimeout != 0 {
+		udpTimeout = time.Duration(options.UDPTimeout)
+	} else {
+		udpTimeout = C.UDPTimeout
+	}
+	tproxy.udpNat = udpnat.New(tproxy, tproxy.preparePacketConnection, udpTimeout, false)
+	tproxy.listener = listener.New(listener.Options{
+		Context:           ctx,
+		Logger:            logger,
+		Network:           options.Network.Build(),
+		Listen:            options.ListenOptions,
+		ConnectionHandler: tproxy,
+		OOBPacketHandler:  tproxy,
+		TProxy:            true,
+	})
+	return tproxy, nil
+}
+
+func (t *TProxy) Start(stage adapter.StartStage) error {
+	if stage != adapter.StartStateStart {
+		return nil
+	}
+	return t.listener.Start()
+}
+
+func (t *TProxy) Close() error {
+	return t.listener.Close()
+}
+
+func (t *TProxy) NewConnectionEx(ctx context.Context, conn net.Conn, metadata adapter.InboundContext, onClose N.CloseHandlerFunc) {
+	metadata.Inbound = t.Tag()
+	metadata.InboundType = t.Type()
+	metadata.Destination = M.SocksaddrFromNet(conn.LocalAddr()).Unwrap()
+	t.logger.InfoContext(ctx, "inbound connection to ", metadata.Destination)
+	t.router.RouteConnectionEx(ctx, conn, metadata, onClose)
+}
+
+func (t *TProxy) NewPacketConnectionEx(ctx context.Context, conn N.PacketConn, source M.Socksaddr, destination M.Socksaddr, onClose N.CloseHandlerFunc) {
+	t.logger.InfoContext(ctx, "inbound packet connection from ", source)
+	t.logger.InfoContext(ctx, "inbound packet connection to ", destination)
+	var metadata adapter.InboundContext
+	metadata.Inbound = t.Tag()
+	metadata.InboundType = t.Type()
+	metadata.Source = source
+	metadata.Destination = destination
+	metadata.OriginDestination = t.listener.UDPAddr()
+	t.router.RoutePacketConnectionEx(ctx, conn, metadata, onClose)
+}
+
+func (t *TProxy) NewPacketEx(buffer *buf.Buffer, oob []byte, source M.Socksaddr) {
+	destination, err := redir.GetOriginalDestinationFromOOB(oob)
+	if err != nil {
+		t.logger.Warn("process packet from ", source, ": get tproxy destination: ", err)
+		return
+	}
+	t.udpNat.NewPacket([][]byte{buffer.Bytes()}, source, M.SocksaddrFromNetIP(destination), nil)
+}
+
+func (t *TProxy) preparePacketConnection(source M.Socksaddr, destination M.Socksaddr, userData any) (bool, context.Context, N.PacketWriter, N.CloseHandlerFunc) {
+	ctx := log.ContextWithNewID(t.ctx)
+	writer := &tproxyPacketWriter{
+		ctx:         ctx,
+		listener:    t.listener,
+		source:      source.AddrPort(),
+		destination: destination,
+	}
+	return true, ctx, writer, func(it error) {
+		common.Close(common.PtrOrNil(writer.conn))
+	}
+}
+
+type tproxyPacketWriter struct {
+	ctx         context.Context
+	listener    *listener.Listener
+	source      netip.AddrPort
+	destination M.Socksaddr
+	conn        *net.UDPConn
+}
+
+func (w *tproxyPacketWriter) WritePacket(buffer *buf.Buffer, destination M.Socksaddr) error {
+	defer buffer.Release()
+	if w.listener.ListenOptions().NetNs == "" {
+		conn := w.conn
+		if w.destination == destination && conn != nil {
+			_, err := conn.WriteToUDPAddrPort(buffer.Bytes(), w.source)
+			if err != nil {
+				w.conn = nil
+			}
+			return err
+		}
+	}
+	var listenConfig net.ListenConfig
+	listenConfig.Control = control.Append(listenConfig.Control, control.ReuseAddr())
+	listenConfig.Control = control.Append(listenConfig.Control, redir.TProxyWriteBack())
+	packetConn, err := w.listener.ListenPacket(listenConfig, w.ctx, "udp", destination.String())
+	if err != nil {
+		return err
+	}
+	udpConn := packetConn.(*net.UDPConn)
+	if w.listener.ListenOptions().NetNs == "" && w.destination == destination {
+		w.conn = udpConn
+	} else {
+		defer udpConn.Close()
+	}
+	return common.Error(udpConn.WriteToUDPAddrPort(buffer.Bytes(), w.source))
+}