Add redir tproxy and dns inbound

inbound/tproxy.go

@@ -0,0 +1,108 @@
+package inbound
+
+import (
+	"context"
+	"net"
+	"net/netip"
+
+	"github.com/sagernet/sing-box/adapter"
+	"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"
+	E "github.com/sagernet/sing/common/exceptions"
+	M "github.com/sagernet/sing/common/metadata"
+	N "github.com/sagernet/sing/common/network"
+	"github.com/sagernet/sing/common/udpnat"
+)
+
+type TProxy struct {
+	myInboundAdapter
+	udpNat *udpnat.Service[netip.AddrPort]
+}
+
+func NewTProxy(ctx context.Context, router adapter.Router, logger log.ContextLogger, tag string, options option.TProxyInboundOptions) *TProxy {
+	tproxy := &TProxy{
+		myInboundAdapter: myInboundAdapter{
+			protocol:      C.TypeTProxy,
+			network:       options.Network.Build(),
+			ctx:           ctx,
+			router:        router,
+			logger:        logger,
+			tag:           tag,
+			listenOptions: options.ListenOptions,
+		},
+	}
+	var udpTimeout int64
+	if options.UDPTimeout != 0 {
+		udpTimeout = options.UDPTimeout
+	} else {
+		udpTimeout = 300
+	}
+	tproxy.connHandler = tproxy
+	tproxy.oobPacketHandler = tproxy
+	tproxy.udpNat = udpnat.New[netip.AddrPort](udpTimeout, tproxy.upstreamContextHandler())
+	tproxy.packetUpstream = tproxy.udpNat
+	return tproxy
+}
+
+func (t *TProxy) Start() error {
+	err := t.myInboundAdapter.Start()
+	if err != nil {
+		return err
+	}
+	if t.tcpListener != nil {
+		tcpFd, err := common.GetFileDescriptor(t.tcpListener)
+		if err != nil {
+			return err
+		}
+		err = redir.TProxy(tcpFd, M.SocksaddrFromNet(t.tcpListener.Addr()).Addr.Is6())
+		if err != nil {
+			return E.Cause(err, "configure tproxy TCP listener")
+		}
+	}
+	if t.udpConn != nil {
+		udpFd, err := common.GetFileDescriptor(t.udpConn)
+		if err != nil {
+			return err
+		}
+		err = redir.TProxyUDP(udpFd, M.SocksaddrFromNet(t.udpConn.LocalAddr()).Addr.Is6())
+		if err != nil {
+			return E.Cause(err, "configure tproxy UDP listener")
+		}
+	}
+	return nil
+}
+
+func (t *TProxy) NewConnection(ctx context.Context, conn net.Conn, metadata adapter.InboundContext) error {
+	metadata.Destination = M.SocksaddrFromNet(conn.LocalAddr())
+	return t.newConnection(ctx, conn, metadata)
+}
+
+func (t *TProxy) NewPacket(ctx context.Context, conn N.PacketConn, buffer *buf.Buffer, oob []byte, metadata adapter.InboundContext) error {
+	destination, err := redir.GetOriginalDestinationFromOOB(oob)
+	if err != nil {
+		return E.Cause(err, "get tproxy destination")
+	}
+	metadata.Destination = M.SocksaddrFromNetIP(destination)
+	t.udpNat.NewContextPacket(ctx, metadata.Source.AddrPort(), buffer, adapter.UpstreamMetadata(metadata), func(natConn N.PacketConn) (context.Context, N.PacketWriter) {
+		return adapter.WithContext(log.ContextWithNewID(ctx), &metadata), &tproxyPacketWriter{natConn}
+	})
+	return nil
+}
+
+type tproxyPacketWriter struct {
+	source N.PacketConn
+}
+
+func (w *tproxyPacketWriter) WritePacket(buffer *buf.Buffer, destination M.Socksaddr) error {
+	defer buffer.Release()
+	udpConn, err := redir.DialUDP(destination.UDPAddr(), M.SocksaddrFromNet(w.source.LocalAddr()).UDPAddr())
+	if err != nil {
+		return E.Cause(err, "tproxy udp write back")
+	}
+	defer udpConn.Close()
+	return common.Error(udpConn.Write(buffer.Bytes()))
+}