Add windows support

internal/wintun/wintun_windows.go

@@ -0,0 +1,112 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
+ */
+
+package wintun
+
+import (
+	"runtime"
+	"syscall"
+	"unsafe"
+
+	"golang.org/x/sys/windows"
+)
+
+type (
+	Adapter struct {
+		handle uintptr
+	}
+)
+
+var (
+	modwintun                         = newLazyDLL("wintun.dll")
+	procWintunCreateAdapter           = modwintun.NewProc("WintunCreateAdapter")
+	procWintunOpenAdapter             = modwintun.NewProc("WintunOpenAdapter")
+	procWintunCloseAdapter            = modwintun.NewProc("WintunCloseAdapter")
+	procWintunDeleteDriver            = modwintun.NewProc("WintunDeleteDriver")
+	procWintunGetAdapterLUID          = modwintun.NewProc("WintunGetAdapterLUID")
+	procWintunGetRunningDriverVersion = modwintun.NewProc("WintunGetRunningDriverVersion")
+)
+
+func closeAdapter(wintun *Adapter) {
+	syscall.SyscallN(procWintunCloseAdapter.Addr(), 1, wintun.handle, 0, 0)
+}
+
+// CreateAdapter creates a Wintun adapter. name is the cosmetic name of the adapter.
+// tunnelType represents the type of adapter and should be "Wintun". requestedGUID is
+// the GUID of the created network adapter, which then influences NLA generation
+// deterministically. If it is set to nil, the GUID is chosen by the system at random,
+// and hence a new NLA entry is created for each new adapter.
+func CreateAdapter(name string, tunnelType string, requestedGUID *windows.GUID) (wintun *Adapter, err error) {
+	var name16 *uint16
+	name16, err = windows.UTF16PtrFromString(name)
+	if err != nil {
+		return
+	}
+	var tunnelType16 *uint16
+	tunnelType16, err = windows.UTF16PtrFromString(tunnelType)
+	if err != nil {
+		return
+	}
+	r0, _, e1 := syscall.Syscall(procWintunCreateAdapter.Addr(), 3, uintptr(unsafe.Pointer(name16)), uintptr(unsafe.Pointer(tunnelType16)), uintptr(unsafe.Pointer(requestedGUID)))
+	if r0 == 0 {
+		err = e1
+		return
+	}
+	wintun = &Adapter{handle: r0}
+	runtime.SetFinalizer(wintun, closeAdapter)
+	return
+}
+
+// OpenAdapter opens an existing Wintun adapter by name.
+func OpenAdapter(name string) (wintun *Adapter, err error) {
+	var name16 *uint16
+	name16, err = windows.UTF16PtrFromString(name)
+	if err != nil {
+		return
+	}
+	r0, _, e1 := syscall.Syscall(procWintunOpenAdapter.Addr(), 1, uintptr(unsafe.Pointer(name16)), 0, 0)
+	if r0 == 0 {
+		err = e1
+		return
+	}
+	wintun = &Adapter{handle: r0}
+	runtime.SetFinalizer(wintun, closeAdapter)
+	return
+}
+
+// Close closes a Wintun adapter.
+func (wintun *Adapter) Close() (err error) {
+	runtime.SetFinalizer(wintun, nil)
+	r1, _, e1 := syscall.Syscall(procWintunCloseAdapter.Addr(), 1, wintun.handle, 0, 0)
+	if r1 == 0 {
+		err = e1
+	}
+	return
+}
+
+// Uninstall removes the driver from the system if no drivers are currently in use.
+func Uninstall() (err error) {
+	r1, _, e1 := syscall.Syscall(procWintunDeleteDriver.Addr(), 0, 0, 0, 0)
+	if r1 == 0 {
+		err = e1
+	}
+	return
+}
+
+// RunningVersion returns the version of the running Wintun driver.
+func RunningVersion() (version uint32, err error) {
+	r0, _, e1 := syscall.Syscall(procWintunGetRunningDriverVersion.Addr(), 0, 0, 0, 0)
+	version = uint32(r0)
+	if version == 0 {
+		err = e1
+	}
+	return
+}
+
+// LUID returns the LUID of the adapter.
+func (wintun *Adapter) LUID() (luid uint64) {
+	syscall.Syscall(procWintunGetAdapterLUID.Addr(), 2, uintptr(wintun.handle), uintptr(unsafe.Pointer(&luid)), 0)
+	return
+}