From 298d759f3efba6b90ea70838d190959b39c5be57 Mon Sep 17 00:00:00 2001
From: "Jason A. Donenfeld" <Jason@zx2c4.com>
Date: Thu, 18 Jul 2019 10:25:12 +0200
Subject: wintun: calculate path of NDIS device object symbolic link

---
 tun/wintun/wintun_windows.go | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/tun/wintun/wintun_windows.go b/tun/wintun/wintun_windows.go
index b8aabf3..160d51f 100644
--- a/tun/wintun/wintun_windows.go
+++ b/tun/wintun/wintun_windows.go
@@ -311,6 +311,9 @@ func CreateInterface(description string, requestedGUID *windows.GUID) (wintun *W
 			waitForRegistryTimeout)
 		if err == nil {
 			_, err = registryEx.GetStringValueWait(key, "Name", waitForRegistryTimeout)
+			if err == nil {
+				_, err = registryEx.GetStringValueWait(key, "PnPInstanceId", waitForRegistryTimeout)
+			}
 			key.Close()
 		}
 	}
@@ -614,6 +617,23 @@ func (wintun *Wintun) DataFileName() string {
 	return fmt.Sprintf("\\\\.\\Global\\WINTUN%d", wintun.luidIndex)
 }
 
+// NdisFileName returns the Wintun NDIS device object name.
+func (wintun *Wintun) NdisFileName() (string, error) {
+	key, err := registry.OpenKey(registry.LOCAL_MACHINE, wintun.netRegKeyName(), registry.QUERY_VALUE)
+	if err != nil {
+		return "", fmt.Errorf("Network-specific registry key open failed: %v", err)
+	}
+	defer key.Close()
+
+	// Get the interface name.
+	pnpInstanceID, err := registryEx.GetStringValue(key, "PnPInstanceId")
+	if err != nil {
+		return "", fmt.Errorf("PnpInstanceId registry key read failed: %v", err)
+	}
+	mangledPnpNode := strings.ReplaceAll(fmt.Sprintf("%s\\{cac88484-7515-4c03-82e6-71a87abac361}", pnpInstanceID), "\\", "#")
+	return fmt.Sprintf("\\\\.\\Global\\%s", mangledPnpNode), nil
+}
+
 // GUID returns the GUID of the interface.
 func (wintun *Wintun) GUID() windows.GUID {
 	return wintun.cfgInstanceID
-- 
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