Add route support

route_gvisor.go

@@ -0,0 +1,16 @@
+//go:build with_gvisor
+
+package tun
+
+import (
+	"github.com/sagernet/sing/common/buf"
+
+	"gvisor.dev/gvisor/pkg/tcpip/stack"
+)
+
+type DirectDestination interface {
+	WritePacket(buffer *buf.Buffer) error
+	WritePacketBuffer(buffer *stack.PacketBuffer) error
+	Close() error
+	Timeout() bool
+}