1 files changed, 10 insertions, 0 deletions
diff --git a/tun/tun_freebsd.go b/tun/tun_freebsd.go
index 53d4f41..37f1a0c 100644
--- a/tun/tun_freebsd.go
+++ b/tun/tun_freebsd.go
@@ -21,6 +21,7 @@ const (
 	_TUNSIFHEAD = 0x80047460
 	_TUNSIFMODE = 0x8004745e
 	_TUNGIFNAME = 0x4020745d
+	_TUNSIFPID  = 0x2000745f
 
 	_SIOCGIFINFO_IN6        = 0xc048696c
 	_SIOCSIFINFO_IN6        = 0xc048696d
@@ -266,6 +267,15 @@ func CreateTUNFromFile(file *os.File, mtu int) (Device, error) {
 		errors:  make(chan error, 1),
 	}
 
+	var errno syscall.Errno
+	tun.operateOnFd(func(fd uintptr) {
+		_, _, errno = unix.Syscall(unix.SYS_IOCTL, fd, _TUNSIFPID, uintptr(0))
+	})
+	if errno != 0 {
+		tun.tunFile.Close()
+		return nil, fmt.Errorf("unable to become controlling TUN process: %w", errno)
+	}
+
 	name, err := tun.Name()
 	if err != nil {
 		tun.tunFile.Close()