Add L3 routing support

outbound/wireguard.go

@@ -8,7 +8,9 @@ import (
 	"encoding/hex"
 	"fmt"
 	"net"
+	"os"
 	"strings"
+	"syscall"
 
 	"github.com/sagernet/sing-box/adapter"
 	"github.com/sagernet/sing-box/common/dialer"
@@ -26,7 +28,7 @@ import (
 )
 
 var (
-	_ adapter.Outbound                = (*WireGuard)(nil)
+	_ adapter.IPOutbound              = (*WireGuard)(nil)
 	_ adapter.InterfaceUpdateListener = (*WireGuard)(nil)
 )
 
@@ -34,6 +36,7 @@ type WireGuard struct {
 	myOutboundAdapter
 	bind      *wireguard.ClientBind
 	device    *device.Device
+	natDevice wireguard.NatDevice
 	tunDevice wireguard.Device
 }
 
@@ -106,17 +109,25 @@ func NewWireGuard(ctx context.Context, router adapter.Router, logger log.Context
 	if mtu == 0 {
 		mtu = 1408
 	}
-	var wireTunDevice wireguard.Device
+	var tunDevice wireguard.Device
 	var err error
 	if !options.SystemInterface && tun.WithGVisor {
-		wireTunDevice, err = wireguard.NewStackDevice(localPrefixes, mtu)
+		tunDevice, err = wireguard.NewStackDevice(localPrefixes, mtu, options.IPRewrite)
 	} else {
-		wireTunDevice, err = wireguard.NewSystemDevice(router, options.InterfaceName, localPrefixes, mtu)
+		tunDevice, err = wireguard.NewSystemDevice(router, options.InterfaceName, localPrefixes, mtu)
 	}
 	if err != nil {
 		return nil, E.Cause(err, "create WireGuard device")
 	}
-	wgDevice := device.NewDevice(wireTunDevice, outbound.bind, &device.Logger{
+	natDevice, isNatDevice := tunDevice.(wireguard.NatDevice)
+	if !isNatDevice && router.NatRequired(tag) {
+		natDevice = wireguard.NewNATDevice(tunDevice, options.IPRewrite)
+	}
+	deviceInput := tunDevice
+	if natDevice != nil {
+		deviceInput = natDevice
+	}
+	wgDevice := device.NewDevice(deviceInput, outbound.bind, &device.Logger{
 		Verbosef: func(format string, args ...interface{}) {
 			logger.Debug(fmt.Sprintf(strings.ToLower(format), args...))
 		},
@@ -132,7 +143,8 @@ func NewWireGuard(ctx context.Context, router adapter.Router, logger log.Context
 		return nil, E.Cause(err, "setup wireguard")
 	}
 	outbound.device = wgDevice
-	outbound.tunDevice = wireTunDevice
+	outbound.natDevice = natDevice
+	outbound.tunDevice = tunDevice
 	return outbound, nil
 }
 
@@ -171,6 +183,27 @@ func (w *WireGuard) NewPacketConnection(ctx context.Context, conn N.PacketConn,
 	return NewPacketConnection(ctx, w, conn, metadata)
 }
 
+func (w *WireGuard) NewIPConnection(ctx context.Context, conn tun.RouteContext, metadata adapter.InboundContext) (tun.DirectDestination, error) {
+	if w.natDevice == nil {
+		return nil, os.ErrInvalid
+	}
+	session := tun.RouteSession{
+		IPVersion:   metadata.IPVersion,
+		Network:     tun.NetworkFromName(metadata.Network),
+		Source:      metadata.Source.AddrPort(),
+		Destination: metadata.Destination.AddrPort(),
+	}
+	switch session.Network {
+	case syscall.IPPROTO_TCP:
+		w.logger.InfoContext(ctx, "linked connection to ", metadata.Destination)
+	case syscall.IPPROTO_UDP:
+		w.logger.InfoContext(ctx, "linked packet connection to ", metadata.Destination)
+	default:
+		w.logger.InfoContext(ctx, "linked ", metadata.Network, " connection to ", metadata.Destination.AddrString())
+	}
+	return w.natDevice.CreateDestination(session, conn), nil
+}
+
 func (w *WireGuard) Start() error {
 	return w.tunDevice.Start()
 }