Add proxy support for ICMP echo request

transport/wireguard/endpoint.go

@@ -10,8 +10,11 @@ import (
 	"os"
 	"reflect"
 	"strings"
+	"time"
 	"unsafe"
 
+	"github.com/sagernet/sing-box/adapter"
+	"github.com/sagernet/sing-tun"
 	"github.com/sagernet/sing/common"
 	E "github.com/sagernet/sing/common/exceptions"
 	F "github.com/sagernet/sing/common/format"
@@ -31,6 +34,7 @@ type Endpoint struct {
 	ipcConf        string
 	allowedAddress []netip.Prefix
 	tunDevice      Device
+	natDevice      NatDevice
 	device         *device.Device
 	allowedIPs     *device.AllowedIPs
 	pause          pause.Manager
@@ -114,12 +118,17 @@ func NewEndpoint(options EndpointOptions) (*Endpoint, error) {
 	if err != nil {
 		return nil, E.Cause(err, "create WireGuard device")
 	}
+	natDevice, isNatDevice := tunDevice.(NatDevice)
+	if !isNatDevice {
+		natDevice = NewNATDevice(options.Context, options.Logger, tunDevice)
+	}
 	return &Endpoint{
 		options:        options,
 		peers:          peers,
 		ipcConf:        ipcConf,
 		allowedAddress: allowedAddresses,
 		tunDevice:      tunDevice,
+		natDevice:      natDevice,
 	}, nil
 }
 
@@ -179,7 +188,13 @@ func (e *Endpoint) Start(resolve bool) error {
 			e.options.Logger.Error(fmt.Sprintf(strings.ToLower(format), args...))
 		},
 	}
-	wgDevice := device.NewDevice(e.options.Context, e.tunDevice, bind, logger, e.options.Workers)
+	var deviceInput Device
+	if e.natDevice != nil {
+		deviceInput = e.natDevice
+	} else {
+		deviceInput = e.tunDevice
+	}
+	wgDevice := device.NewDevice(e.options.Context, deviceInput, bind, logger, e.options.Workers)
 	e.tunDevice.SetDevice(wgDevice)
 	ipcConf := e.ipcConf
 	for _, peer := range e.peers {
@@ -229,6 +244,13 @@ func (e *Endpoint) Lookup(address netip.Addr) *device.Peer {
 	return e.allowedIPs.Lookup(address.AsSlice())
 }
 
+func (e *Endpoint) NewDirectRouteConnection(metadata adapter.InboundContext, routeContext tun.DirectRouteContext, timeout time.Duration) (tun.DirectRouteDestination, error) {
+	if e.natDevice == nil {
+		return nil, os.ErrInvalid
+	}
+	return e.natDevice.CreateDestination(metadata, routeContext, timeout)
+}
+
 func (e *Endpoint) onPauseUpdated(event int) {
 	switch event {
 	case pause.EventDevicePaused, pause.EventNetworkPause: