wintun: simplify resolution of dev node

diff --git a/tun/wintun/wintun_windows.go b/tun/wintun/wintun_windows.go
index 9be2b17ec4d8adc03a7da42b4eb401f8ca128c20..0dabcbb70eee6a5d736e9509a152b6b04e145fcb 100644 (file)
--- a/tun/wintun/wintun_windows.go
+++ b/tun/wintun/wintun_windows.go
@@ -23,11 +23,13 @@ import (
 // Wintun is a handle of a Wintun adapter.
 type Wintun struct {
        cfgInstanceID windows.GUID
+       devInstanceID string
        luidIndex     uint32
        ifType        uint32
 }
 
 var deviceClassNetGUID = windows.GUID{Data1: 0x4d36e972, Data2: 0xe325, Data3: 0x11ce, Data4: [8]byte{0xbf, 0xc1, 0x08, 0x00, 0x2b, 0xe1, 0x03, 0x18}}
+var deviceInterfaceNetGUID = windows.GUID{Data1: 0xcac88484, Data2: 0x7515, Data3: 0x4c03, Data4: [8]byte{ 0x82, 0xe6, 0x71, 0xa8, 0x7a, 0xba, 0xc3, 0x61}}
 
 const (
        hardwareID             = "Wintun"
@@ -67,8 +69,14 @@ func makeWintun(deviceInfoSet setupapi.DevInfo, deviceInfoData *setupapi.DevInfo
                return nil, fmt.Errorf("RegQueryValue(\"*IfType\") failed: %v", err)
        }
 
+       instanceId, err := deviceInfoSet.DeviceInstanceID(deviceInfoData)
+       if err != nil {
+               return nil, fmt.Errorf("DeviceInstanceID failed: %v", err)
+       }
+
        return &Wintun{
                cfgInstanceID: ifid,
+               devInstanceID: instanceId,
                luidIndex:     uint32(luidIdx),
                ifType:        uint32(ifType),
        }, nil
@@ -614,21 +622,10 @@ func (wintun *Wintun) deviceData() (setupapi.DevInfo, *setupapi.DevInfoData, err
 
 // AdapterHandle returns a handle to the adapter device object.
 func (wintun *Wintun) AdapterHandle() (windows.Handle, error) {
-       key, err := registry.OpenKey(registry.LOCAL_MACHINE, wintun.netRegKeyName(), registry.QUERY_VALUE)
-       if err != nil {
-               return windows.InvalidHandle, 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 windows.InvalidHandle, fmt.Errorf("PnPInstanceId registry key read failed: %v", err)
-       }
-       mangledPnpNode := strings.ReplaceAll(fmt.Sprintf("%s\\{cac88484-7515-4c03-82e6-71a87abac361}", pnpInstanceID), "\\", "#")
+       mangledPnpNode := strings.ReplaceAll(fmt.Sprintf("%s\\%s", wintun.devInstanceID, deviceInterfaceNetGUID.String()), "\\", "#")
        handle, err := windows.CreateFile(windows.StringToUTF16Ptr(fmt.Sprintf("\\\\.\\Global\\%s", mangledPnpNode)), windows.GENERIC_READ|windows.GENERIC_WRITE, windows.FILE_SHARE_READ | windows.FILE_SHARE_WRITE | windows.FILE_SHARE_DELETE, nil, windows.OPEN_EXISTING, 0, 0)
        if err != nil {
-               return windows.InvalidHandle, fmt.Errorf("CreateFile on mangled PnPInstanceId path failed: %v", err)
+               return windows.InvalidHandle, fmt.Errorf("Open NDIS device failed: %v", err)
        }
        return handle, nil
 }