From 31ff9c02fec42f38b0e444c41744887a1b9fedaf Mon Sep 17 00:00:00 2001
From: "Jason A. Donenfeld" <Jason@zx2c4.com>
Date: Thu, 18 Jul 2019 19:26:25 +0200
Subject: [PATCH] tun: windows: open file at startup time

---
 tun/tun_windows.go | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/tun/tun_windows.go b/tun/tun_windows.go
index 86995a7..dff51dd 100644
--- a/tun/tun_windows.go
+++ b/tun/tun_windows.go
@@ -142,6 +142,15 @@ func CreateTUNWithRequestedGUID(ifname string, requestedGUID *windows.GUID) (Dev
 		return nil, fmt.Errorf("Error creating event: %v", err)
 	}
 
+	_, err = tun.getTUN()
+	if err != nil {
+		windows.CloseHandle(tun.rings.send.tailMoved)
+		windows.CloseHandle(tun.rings.receive.tailMoved)
+		tun.closeTUN()
+		wt.DeleteInterface()
+		return nil, err
+	}
+
 	return tun, nil
 }