wintun: use nci.dll directly instead of buggy netshell

tun/wintun/nci/mksyscall.go

@@ -0,0 +1,8 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package nci
+
+//go:generate go run $GOROOT/src/syscall/mksyscall_windows.go -output zsyscall_windows.go nci_windows.go

tun/wintun/nci/nci_windows.go

@@ -0,0 +1,28 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package nci
+
+import "golang.org/x/sys/windows"
+
+//sys	nciSetConnectionName(guid *windows.GUID, newName *uint16) (ret error) = nci.NciSetConnectionName
+//sys	nciGetConnectionName(guid *windows.GUID, destName *uint16, inDestNameBytes uint32, outDestNameBytes *uint32) (ret error) = nci.NciGetConnectionName
+
+func SetConnectionName(guid *windows.GUID, newName string) error {
+	newName16, err := windows.UTF16PtrFromString(newName)
+	if err != nil {
+		return err
+	}
+	return nciSetConnectionName(guid, newName16)
+}
+
+func ConnectionName(guid *windows.GUID) (string, error) {
+	var name [0x400]uint16
+	err := nciGetConnectionName(guid, &name[0], uint32(len(name)*2), nil)
+	if err != nil {
+		return "", err
+	}
+	return windows.UTF16ToString(name[:]), nil
+}

tun/wintun/nci/zsyscall_windows.go

@@ -0,0 +1,60 @@
+// Code generated by 'go generate'; DO NOT EDIT.
+
+package nci
+
+import (
+	"syscall"
+	"unsafe"
+
+	"golang.org/x/sys/windows"
+)
+
+var _ unsafe.Pointer
+
+// Do the interface allocations only once for common
+// Errno values.
+const (
+	errnoERROR_IO_PENDING = 997
+)
+
+var (
+	errERROR_IO_PENDING error = syscall.Errno(errnoERROR_IO_PENDING)
+)
+
+// errnoErr returns common boxed Errno values, to prevent
+// allocations at runtime.
+func errnoErr(e syscall.Errno) error {
+	switch e {
+	case 0:
+		return nil
+	case errnoERROR_IO_PENDING:
+		return errERROR_IO_PENDING
+	}
+	// TODO: add more here, after collecting data on the common
+	// error values see on Windows. (perhaps when running
+	// all.bat?)
+	return e
+}
+
+var (
+	modnci = windows.NewLazySystemDLL("nci.dll")
+
+	procNciSetConnectionName = modnci.NewProc("NciSetConnectionName")
+	procNciGetConnectionName = modnci.NewProc("NciGetConnectionName")
+)
+
+func nciSetConnectionName(guid *windows.GUID, newName *uint16) (ret error) {
+	r0, _, _ := syscall.Syscall(procNciSetConnectionName.Addr(), 2, uintptr(unsafe.Pointer(guid)), uintptr(unsafe.Pointer(newName)), 0)
+	if r0 != 0 {
+		ret = syscall.Errno(r0)
+	}
+	return
+}
+
+func nciGetConnectionName(guid *windows.GUID, destName *uint16, inDestNameBytes uint32, outDestNameBytes *uint32) (ret error) {
+	r0, _, _ := syscall.Syscall6(procNciGetConnectionName.Addr(), 4, uintptr(unsafe.Pointer(guid)), uintptr(unsafe.Pointer(destName)), uintptr(inDestNameBytes), uintptr(unsafe.Pointer(outDestNameBytes)), 0, 0)
+	if r0 != 0 {
+		ret = syscall.Errno(r0)
+	}
+	return
+}

tun/wintun/netshell/netshell_windows.go

@@ -1,32 +0,0 @@
-/* SPDX-License-Identifier: MIT
- *
- * Copyright (C) 2019 WireGuard LLC. All Rights Reserved.
- */
-
-package netshell
-
-import (
-	"syscall"
-	"unsafe"
-
-	"golang.org/x/sys/windows"
-)
-
-var (
-	modnetshell            = windows.NewLazySystemDLL("netshell.dll")
-	procHrRenameConnection = modnetshell.NewProc("HrRenameConnection")
-)
-
-func HrRenameConnection(guid *windows.GUID, newName *uint16) (err error) {
-	err = procHrRenameConnection.Find()
-	if err != nil {
-		// Missing from servercore, so we can't presume it's always there.
-		return
-	}
-
-	ret, _, _ := syscall.Syscall(procHrRenameConnection.Addr(), 2, uintptr(unsafe.Pointer(guid)), uintptr(unsafe.Pointer(newName)), 0)
-	if ret != 0 {
-		err = syscall.Errno(ret)
-	}
-	return
-}

tun/wintun/wintun_windows.go

@@ -15,7 +15,7 @@ import (
 	"golang.org/x/sys/windows"
 	"golang.org/x/sys/windows/registry"
 
-	"golang.zx2c4.com/wireguard/tun/wintun/netshell"
+	"golang.zx2c4.com/wireguard/tun/wintun/nci"
 	registryEx "golang.zx2c4.com/wireguard/tun/wintun/registry"
 	"golang.zx2c4.com/wireguard/tun/wintun/setupapi"
 )
@@ -348,28 +348,6 @@ func CreateInterface(description string, requestedGUID *windows.GUID) (wintun *W
 		return
 	}
 
-	// Wait for network registry key to emerge and populate.
-	netRegKey, err := registryEx.OpenKeyWait(
-		registry.LOCAL_MACHINE,
-		wintun.netRegKeyName(),
-		registry.QUERY_VALUE|registry.NOTIFY,
-		waitForRegistryTimeout)
-	if err != nil {
-		err = fmt.Errorf("makeWintun failed: %v", err)
-		return
-	}
-	defer netRegKey.Close()
-	_, err = registryEx.GetStringValueWait(netRegKey, "Name", waitForRegistryTimeout)
-	if err != nil {
-		err = fmt.Errorf("GetStringValueWait(Name) failed: %v", err)
-		return
-	}
-	_, err = registryEx.GetStringValueWait(netRegKey, "PnPInstanceId", waitForRegistryTimeout)
-	if err != nil {
-		err = fmt.Errorf("GetStringValueWait(PnPInstanceId) failed: %v", err)
-		return
-	}
-
 	// Wait for TCP/IP adapter registry key to emerge and populate.
 	tcpipAdapterRegKey, err := registryEx.OpenKeyWait(
 		registry.LOCAL_MACHINE,
@@ -539,29 +517,17 @@ func setQuietInstall(deviceInfoSet setupapi.DevInfo, deviceInfoData *setupapi.De
 
 // InterfaceName returns the name of the Wintun interface.
 func (wintun *Wintun) InterfaceName() (string, error) {
-	key, err := registry.OpenKey(registry.LOCAL_MACHINE, wintun.netRegKeyName(), registry.QUERY_VALUE)
+	return nci.ConnectionName(&wintun.cfgInstanceID)
-	if err != nil {
-		return "", fmt.Errorf("Network-specific registry key open failed: %v", err)
-	}
-	defer key.Close()
-
-	// Get the interface name.
-	return registryEx.GetStringValue(key, "Name")
 }
 
 // SetInterfaceName sets name of the Wintun interface.
 func (wintun *Wintun) SetInterfaceName(ifname string) error {
-	netRegKey, err := registry.OpenKey(registry.LOCAL_MACHINE, wintun.netRegKeyName(), registry.SET_VALUE)
+	err := nci.SetConnectionName(&wintun.cfgInstanceID, ifname)
 	if err != nil {
-		return fmt.Errorf("Network-specific registry key open failed: %v", err)
+		return fmt.Errorf("NciSetConnectionName failed: %v", err)
-	}
-	defer netRegKey.Close()
-	err = netRegKey.SetStringValue("Name", ifname)
-	if err != nil {
-		return err
 	}
 
-	// TODO: This only sometimes works.
+	// TODO: This should use NetSetup2 so that it doesn't get unset.
 	deviceRegKey, err := registry.OpenKey(registry.LOCAL_MACHINE, wintun.deviceRegKeyName(), registry.SET_VALUE)
 	if err != nil {
 		return fmt.Errorf("Device-level registry key open failed: %v", err)
@@ -569,23 +535,11 @@ func (wintun *Wintun) SetInterfaceName(ifname string) error {
 	defer deviceRegKey.Close()
 	err = deviceRegKey.SetStringValue("FriendlyName", deviceTypeName)
 	if err != nil {
-		return err
+		return fmt.Errorf("SetStringValue(FriendlyName) failed: %v", err)
 	}
-
-	// We have to tell the various runtime COM services about the new name too. We ignore the
-	// error because netshell isn't available on servercore.
-	// TODO: netsh.exe falls back to NciSetConnection in this case. If somebody complains, maybe
-	// we should do the same.
-	// TODO: This only sometimes works.
-	netshell.HrRenameConnection(&wintun.cfgInstanceID, windows.StringToUTF16Ptr(ifname))
 	return nil
 }
 
-// netRegKeyName returns the interface-specific network registry key name.
-func (wintun *Wintun) netRegKeyName() string {
-	return fmt.Sprintf("SYSTEM\\CurrentControlSet\\Control\\Network\\%v\\%v\\Connection", deviceClassNetGUID, wintun.cfgInstanceID)
-}
-
 // tcpipAdapterRegKeyName returns the adapter-specific TCP/IP network registry key name.
 func (wintun *Wintun) tcpipAdapterRegKeyName() string {
 	return fmt.Sprintf("SYSTEM\\CurrentControlSet\\Services\\Tcpip\\Parameters\\Adapters\\%v", wintun.cfgInstanceID)