wintun: use new swdevice-based API for upcoming Wintun 0.14

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

2 files changed, 61 insertions, 149 deletions

diff --git a/tun/tun_windows.go b/tun/tun_windows.go
index ff16e2f..381a842 100644
--- a/tun/tun_windows.go
+++ b/tun/tun_windows.go
@@ -8,7 +8,6 @@ package tun
 import (
 	"errors"
 	"fmt"
-	"log"
 	"os"
 	"sync"
 	"sync/atomic"
@@ -35,6 +34,7 @@ type rateJuggler struct {
 
 type NativeTun struct {
 	wt        *wintun.Adapter
+	name      string
 	handle    windows.Handle
 	rate      rateJuggler
 	session   wintun.Session
@@ -46,7 +46,7 @@ type NativeTun struct {
 	forcedMTU int
 }
 
-var WintunPool, _ = wintun.MakePool("WireGuard")
+var WintunTunnelType = "WireGuard"
 var WintunStaticRequestedGUID *windows.GUID
 
 //go:linkname procyield runtime.procyield
@@ -68,25 +68,10 @@ func CreateTUN(ifname string, mtu int) (Device, error) {
 // a requested GUID. Should a Wintun interface with the same name exist, it is reused.
 //
 func CreateTUNWithRequestedGUID(ifname string, requestedGUID *windows.GUID, mtu int) (Device, error) {
-	var err error
-	var wt *wintun.Adapter
-
-	// Does an interface with this name already exist?
-	wt, err = WintunPool.OpenAdapter(ifname)
-	if err == nil {
-		// If so, we delete it, in case it has weird residual configuration.
-		_, err = wt.Delete(true)
-		if err != nil {
-			return nil, fmt.Errorf("Error deleting already existing interface: %w", err)
-		}
-	}
-	wt, rebootRequired, err := WintunPool.CreateAdapter(ifname, requestedGUID)
+	wt, err := wintun.CreateAdapter(ifname, WintunTunnelType, requestedGUID)
 	if err != nil {
 		return nil, fmt.Errorf("Error creating interface: %w", err)
 	}
-	if rebootRequired {
-		log.Println("Windows indicated a reboot is required.")
-	}
 
 	forcedMTU := 1420
 	if mtu > 0 {
@@ -95,6 +80,7 @@ func CreateTUNWithRequestedGUID(ifname string, requestedGUID *windows.GUID, mtu
 
 	tun := &NativeTun{
 		wt:        wt,
+		name:      ifname,
 		handle:    windows.InvalidHandle,
 		events:    make(chan Event, 10),
 		forcedMTU: forcedMTU,
@@ -102,7 +88,7 @@ func CreateTUNWithRequestedGUID(ifname string, requestedGUID *windows.GUID, mtu
 
 	tun.session, err = wt.StartSession(0x800000) // Ring capacity, 8 MiB
 	if err != nil {
-		tun.wt.Delete(false)
+		tun.wt.Close()
 		close(tun.events)
 		return nil, fmt.Errorf("Error starting session: %w", err)
 	}
@@ -111,12 +97,7 @@ func CreateTUNWithRequestedGUID(ifname string, requestedGUID *windows.GUID, mtu
 }
 
 func (tun *NativeTun) Name() (string, error) {
-	tun.running.Add(1)
-	defer tun.running.Done()
-	if atomic.LoadInt32(&tun.close) == 1 {
-		return "", os.ErrClosed
-	}
-	return tun.wt.Name()
+	return tun.name, nil
 }
 
 func (tun *NativeTun) File() *os.File {
@@ -135,7 +116,7 @@ func (tun *NativeTun) Close() error {
 		tun.running.Wait()
 		tun.session.End()
 		if tun.wt != nil {
-			_, err = tun.wt.Delete(false)
+			tun.wt.Close()
 		}
 		close(tun.events)
 	})
diff --git a/tun/wintun/wintun_windows.go b/tun/wintun/wintun_windows.go
index 6c5a00d..4edad91 100644
--- a/tun/wintun/wintun_windows.go
+++ b/tun/wintun/wintun_windows.go
@@ -6,7 +6,6 @@
 package wintun
 
 import (
-	"errors"
 	"log"
 	"runtime"
 	"syscall"
@@ -23,175 +22,107 @@ const (
 	logErr
 )
 
-const (
-	PoolNameMax    = 256
-	AdapterNameMax = 128
-)
+const AdapterNameMax = 128
 
-type Pool [PoolNameMax]uint16
 type Adapter struct {
 	handle uintptr
 }
 
 var (
-	modwintun = newLazyDLL("wintun.dll", setupLogger)
-
+	modwintun                         = newLazyDLL("wintun.dll", setupLogger)
 	procWintunCreateAdapter           = modwintun.NewProc("WintunCreateAdapter")
-	procWintunDeleteAdapter           = modwintun.NewProc("WintunDeleteAdapter")
-	procWintunDeletePoolDriver        = modwintun.NewProc("WintunDeletePoolDriver")
-	procWintunEnumAdapters            = modwintun.NewProc("WintunEnumAdapters")
-	procWintunFreeAdapter             = modwintun.NewProc("WintunFreeAdapter")
 	procWintunOpenAdapter             = modwintun.NewProc("WintunOpenAdapter")
+	procWintunCloseAdapter            = modwintun.NewProc("WintunCloseAdapter")
+	procWintunDeleteDriver            = modwintun.NewProc("WintunDeleteDriver")
 	procWintunGetAdapterLUID          = modwintun.NewProc("WintunGetAdapterLUID")
-	procWintunGetAdapterName          = modwintun.NewProc("WintunGetAdapterName")
 	procWintunGetRunningDriverVersion = modwintun.NewProc("WintunGetRunningDriverVersion")
-	procWintunSetAdapterName          = modwintun.NewProc("WintunSetAdapterName")
 )
 
-func setupLogger(dll *lazyDLL) {
-	syscall.Syscall(dll.NewProc("WintunSetLogger").Addr(), 1, windows.NewCallback(func(level loggerLevel, msg *uint16) int {
-		log.Println("[Wintun]", windows.UTF16PtrToString(msg))
-		return 0
-	}), 0, 0)
+type TimestampedWriter interface {
+	WriteWithTimestamp(p []byte, ts int64) (n int, err error)
 }
 
-func MakePool(poolName string) (pool *Pool, err error) {
-	poolName16, err := windows.UTF16FromString(poolName)
-	if err != nil {
-		return
-	}
-	if len(poolName16) > PoolNameMax {
-		err = errors.New("Pool name too long")
-		return
+func logMessage(level loggerLevel, timestamp uint64, msg *uint16) int {
+	if tw, ok := log.Default().Writer().(TimestampedWriter); ok {
+		tw.WriteWithTimestamp([]byte(log.Default().Prefix()+windows.UTF16PtrToString(msg)), (int64(timestamp)-116444736000000000)*100)
+	} else {
+		log.Println(windows.UTF16PtrToString(msg))
 	}
-	pool = &Pool{}
-	copy(pool[:], poolName16)
-	return
+	return 0
 }
 
-func (pool *Pool) String() string {
-	return windows.UTF16ToString(pool[:])
+func setupLogger(dll *lazyDLL) {
+	var callback uintptr
+	if runtime.GOARCH == "386" || runtime.GOARCH == "arm" {
+		callback = windows.NewCallback(func(level loggerLevel, timestampLow, timestampHigh uint32, msg *uint16) int {
+			return logMessage(level, uint64(timestampHigh)<<32|uint64(timestampLow), msg)
+		})
+	} else if runtime.GOARCH == "amd64" || runtime.GOARCH == "arm64" {
+		callback = windows.NewCallback(logMessage)
+	}
+	syscall.Syscall(dll.NewProc("WintunSetLogger").Addr(), 1, callback, 0, 0)
 }
 
-func freeAdapter(wintun *Adapter) {
-	syscall.Syscall(procWintunFreeAdapter.Addr(), 1, uintptr(wintun.handle), 0, 0)
+func closeAdapter(wintun *Adapter) {
+	syscall.Syscall(procWintunCloseAdapter.Addr(), 1, wintun.handle, 0, 0)
 }
 
-// OpenAdapter finds a Wintun adapter by its name. This function returns the adapter if found, or
-// windows.ERROR_FILE_NOT_FOUND otherwise. If the adapter is found but not a Wintun-class or a
-// member of the pool, this function returns windows.ERROR_ALREADY_EXISTS. The adapter must be
-// released after use.
-func (pool *Pool) OpenAdapter(ifname string) (wintun *Adapter, err error) {
-	ifname16, err := windows.UTF16PtrFromString(ifname)
+// 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 nil, err
-	}
-	r0, _, e1 := syscall.Syscall(procWintunOpenAdapter.Addr(), 2, uintptr(unsafe.Pointer(pool)), uintptr(unsafe.Pointer(ifname16)), 0)
-	if r0 == 0 {
-		err = e1
 		return
 	}
-	wintun = &Adapter{r0}
-	runtime.SetFinalizer(wintun, freeAdapter)
-	return
-}
-
-// CreateAdapter creates a Wintun adapter. ifname is the requested name of the adapter, while
-// 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. It is called "requested" GUID because the API it
-// uses is completely undocumented, and so there could be minor interesting complications with its
-// usage. This function returns the network adapter ID and a flag if reboot is required.
-func (pool *Pool) CreateAdapter(ifname string, requestedGUID *windows.GUID) (wintun *Adapter, rebootRequired bool, err error) {
-	var ifname16 *uint16
-	ifname16, err = windows.UTF16PtrFromString(ifname)
+	var tunnelType16 *uint16
+	tunnelType16, err = windows.UTF16PtrFromString(tunnelType)
 	if err != nil {
 		return
 	}
-	var _p0 uint32
-	r0, _, e1 := syscall.Syscall6(procWintunCreateAdapter.Addr(), 4, uintptr(unsafe.Pointer(pool)), uintptr(unsafe.Pointer(ifname16)), uintptr(unsafe.Pointer(requestedGUID)), uintptr(unsafe.Pointer(&_p0)), 0, 0)
-	rebootRequired = _p0 != 0
+	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{r0}
-	runtime.SetFinalizer(wintun, freeAdapter)
-	return
-}
-
-// Delete deletes a Wintun adapter. This function succeeds if the adapter was not found. It returns
-// a bool indicating whether a reboot is required.
-func (wintun *Adapter) Delete(forceCloseSessions bool) (rebootRequired bool, err error) {
-	var _p0 uint32
-	if forceCloseSessions {
-		_p0 = 1
-	}
-	var _p1 uint32
-	r1, _, e1 := syscall.Syscall(procWintunDeleteAdapter.Addr(), 3, uintptr(wintun.handle), uintptr(_p0), uintptr(unsafe.Pointer(&_p1)))
-	rebootRequired = _p1 != 0
-	if r1 == 0 {
-		err = e1
-	}
+	wintun = &Adapter{handle: r0}
+	runtime.SetFinalizer(wintun, closeAdapter)
 	return
 }
 
-// DeleteMatchingAdapters deletes all Wintun adapters, which match
-// given criteria, and returns which ones it deleted, whether a reboot
-// is required after, and which errors occurred during the process.
-func (pool *Pool) DeleteMatchingAdapters(matches func(adapter *Adapter) bool, forceCloseSessions bool) (rebootRequired bool, errors []error) {
-	cb := func(handle uintptr, _ uintptr) int {
-		adapter := &Adapter{handle}
-		if !matches(adapter) {
-			return 1
-		}
-		rebootRequired2, err := adapter.Delete(forceCloseSessions)
-		if err != nil {
-			errors = append(errors, err)
-			return 1
-		}
-		rebootRequired = rebootRequired || rebootRequired2
-		return 1
-	}
-	r1, _, e1 := syscall.Syscall(procWintunEnumAdapters.Addr(), 3, uintptr(unsafe.Pointer(pool)), uintptr(windows.NewCallback(cb)), 0)
-	if r1 == 0 {
-		errors = append(errors, e1)
+// 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
 	}
-	return
-}
-
-// Name returns the name of the Wintun adapter.
-func (wintun *Adapter) Name() (ifname string, err error) {
-	var ifname16 [AdapterNameMax]uint16
-	r1, _, e1 := syscall.Syscall(procWintunGetAdapterName.Addr(), 2, uintptr(wintun.handle), uintptr(unsafe.Pointer(&ifname16[0])), 0)
-	if r1 == 0 {
+	r0, _, e1 := syscall.Syscall(procWintunOpenAdapter.Addr(), 1, uintptr(unsafe.Pointer(name16)), 0, 0)
+	if r0 == 0 {
 		err = e1
 		return
 	}
-	ifname = windows.UTF16ToString(ifname16[:])
+	wintun = &Adapter{handle: r0}
+	runtime.SetFinalizer(wintun, closeAdapter)
 	return
 }
 
-// DeleteDriver deletes all Wintun adapters in a pool and if there are no more adapters in any other
-// pools, also removes Wintun from the driver store, usually called by uninstallers.
-func (pool *Pool) DeleteDriver() (rebootRequired bool, err error) {
-	var _p0 uint32
-	r1, _, e1 := syscall.Syscall(procWintunDeletePoolDriver.Addr(), 2, uintptr(unsafe.Pointer(pool)), uintptr(unsafe.Pointer(&_p0)), 0)
-	rebootRequired = _p0 != 0
+// 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
-
 }
 
-// SetName sets name of the Wintun adapter.
-func (wintun *Adapter) SetName(ifname string) (err error) {
-	ifname16, err := windows.UTF16FromString(ifname)
-	if err != nil {
-		return err
-	}
-	r1, _, e1 := syscall.Syscall(procWintunSetAdapterName.Addr(), 2, uintptr(wintun.handle), uintptr(unsafe.Pointer(&ifname16[0])), 0)
+// 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
 	}