Fix platform interface monitor & Fix system tun stack for ios

experimental/libbox/tun_name_darwin.go

@@ -0,0 +1,11 @@
+package libbox
+
+import "golang.org/x/sys/unix"
+
+func getTunnelName(fd int32) (string, error) {
+	return unix.GetsockoptString(
+		int(fd),
+		2, /* #define SYSPROTO_CONTROL 2 */
+		2, /* #define UTUN_OPT_IFNAME 2 */
+	)
+}