First Commmit

experimental/libbox/tun_name_linux.go

@@ -0,0 +1,26 @@
+package libbox
+
+import (
+	"fmt"
+	"syscall"
+	"unsafe"
+
+	"golang.org/x/sys/unix"
+)
+
+const ifReqSize = unix.IFNAMSIZ + 64
+
+func getTunnelName(fd int32) (string, error) {
+	var ifr [ifReqSize]byte
+	var errno syscall.Errno
+	_, _, errno = unix.Syscall(
+		unix.SYS_IOCTL,
+		uintptr(fd),
+		uintptr(unix.TUNGETIFF),
+		uintptr(unsafe.Pointer(&ifr[0])),
+	)
+	if errno != 0 {
+		return "", fmt.Errorf("failed to get name of TUN device: %w", errno)
+	}
+	return unix.ByteSliceToString(ifr[:]), nil
+}