version: bump snapshot

Coauthored-by: Andrej Mihajlov <and@mullvad.net>

README.md

@@ -18,7 +18,7 @@ To run wireguard-go without forking to the background, pass `-f` or `--foregroun
 $ wireguard-go -f wg0
 ```
 
-When an interface is running, you may use [`wg(8)`](https://git.zx2c4.com/WireGuard/about/src/tools/man/wg.8) to configure it, as well as the usual `ip(8)` and `ifconfig(8)` commands.
+When an interface is running, you may use [`wg(8)`](https://git.zx2c4.com/wireguard-tools/about/src/man/wg.8) to configure it, as well as the usual `ip(8)` and `ifconfig(8)` commands.
 
 To run with more logging you may set the environment variable `LOG_LEVEL=debug`.
 

device/boundif_windows.go

@@ -18,7 +18,7 @@ const (
 	sockoptIPV6_UNICAST_IF = 31
 )
 
-func (device *Device) BindSocketToInterface4(interfaceIndex uint32) error {
+func (device *Device) BindSocketToInterface4(interfaceIndex uint32, blackhole bool) error {
 	/* MSDN says for IPv4 this needs to be in net byte order, so that it's like an IP address with leading zeros. */
 	bytes := make([]byte, 4)
 	binary.BigEndian.PutUint32(bytes, interfaceIndex)
@@ -41,10 +41,11 @@ func (device *Device) BindSocketToInterface4(interfaceIndex uint32) error {
 	if err != nil {
 		return err
 	}
+	device.net.bind.(*nativeBind).blackhole4 = blackhole
 	return nil
 }
 
-func (device *Device) BindSocketToInterface6(interfaceIndex uint32) error {
+func (device *Device) BindSocketToInterface6(interfaceIndex uint32, blackhole bool) error {
 	sysconn, err := device.net.bind.(*nativeBind).ipv6.SyscallConn()
 	if err != nil {
 		return err
@@ -58,5 +59,6 @@ func (device *Device) BindSocketToInterface6(interfaceIndex uint32) error {
 	if err != nil {
 		return err
 	}
+	device.net.bind.(*nativeBind).blackhole6 = blackhole
 	return nil
 }

device/conn_default.go

@@ -21,8 +21,10 @@ import (
  */
 
 type nativeBind struct {
-	ipv4 *net.UDPConn
+	ipv4       *net.UDPConn
-	ipv6 *net.UDPConn
+	ipv6       *net.UDPConn
+	blackhole4 bool
+	blackhole6 bool
 }
 
 type NativeEndpoint net.UDPAddr
@@ -159,11 +161,17 @@ func (bind *nativeBind) Send(buff []byte, endpoint Endpoint) error {
 		if bind.ipv4 == nil {
 			return syscall.EAFNOSUPPORT
 		}
+		if bind.blackhole4 {
+			return nil
+		}
 		_, err = bind.ipv4.WriteToUDP(buff, (*net.UDPAddr)(nend))
 	} else {
 		if bind.ipv6 == nil {
 			return syscall.EAFNOSUPPORT
 		}
+		if bind.blackhole6 {
+			return nil
+		}
 		_, err = bind.ipv6.WriteToUDP(buff, (*net.UDPAddr)(nend))
 	}
 	return err

device/conn_linux.go

@@ -7,7 +7,7 @@
  * This implements userspace semantics of "sticky sockets", modeled after
  * WireGuard's kernelspace implementation. This is more or less a straight port
  * of the sticky-sockets.c example code:
- * https://git.zx2c4.com/WireGuard/tree/contrib/examples/sticky-sockets/sticky-sockets.c
+ * https://git.zx2c4.com/wireguard-tools/tree/contrib/sticky-sockets/sticky-sockets.c
  *
  * Currently there is no way to achieve this within the net package:
  * See e.g. https://github.com/golang/go/issues/17930
@@ -43,6 +43,7 @@ type IPv6Source struct {
 }
 
 type NativeEndpoint struct {
+	sync.Mutex
 	dst  [unsafe.Sizeof(unix.SockaddrInet6{})]byte
 	src  [unsafe.Sizeof(IPv6Source{})]byte
 	isV6 bool
@@ -145,7 +146,7 @@ func CreateBind(port uint16, device *Device) (*nativeBind, uint16, error) {
 
 	go bind.routineRouteListener(device)
 
-	// attempt ipv6 bind, update port if succesful
+	// attempt ipv6 bind, update port if successful
 
 	bind.sock6, newPort, err = create6(port)
 	if err != nil {
@@ -157,7 +158,7 @@ func CreateBind(port uint16, device *Device) (*nativeBind, uint16, error) {
 		port = newPort
 	}
 
-	// attempt ipv4 bind, update port if succesful
+	// attempt ipv4 bind, update port if successful
 
 	bind.sock4, newPort, err = create4(port)
 	if err != nil {
@@ -482,7 +483,9 @@ func send4(sock int, end *NativeEndpoint, buff []byte) error {
 		},
 	}
 
+	end.Lock()
 	_, err := unix.SendmsgN(sock, buff, (*[unsafe.Sizeof(cmsg)]byte)(unsafe.Pointer(&cmsg))[:], end.dst4(), 0)
+	end.Unlock()
 
 	if err == nil {
 		return nil
@@ -493,7 +496,9 @@ func send4(sock int, end *NativeEndpoint, buff []byte) error {
 	if err == unix.EINVAL {
 		end.ClearSrc()
 		cmsg.pktinfo = unix.Inet4Pktinfo{}
+		end.Lock()
 		_, err = unix.SendmsgN(sock, buff, (*[unsafe.Sizeof(cmsg)]byte)(unsafe.Pointer(&cmsg))[:], end.dst4(), 0)
+		end.Unlock()
 	}
 
 	return err
@@ -522,7 +527,9 @@ func send6(sock int, end *NativeEndpoint, buff []byte) error {
 		cmsg.pktinfo.Ifindex = 0
 	}
 
+	end.Lock()
 	_, err := unix.SendmsgN(sock, buff, (*[unsafe.Sizeof(cmsg)]byte)(unsafe.Pointer(&cmsg))[:], end.dst6(), 0)
+	end.Unlock()
 
 	if err == nil {
 		return nil
@@ -533,7 +540,9 @@ func send6(sock int, end *NativeEndpoint, buff []byte) error {
 	if err == unix.EINVAL {
 		end.ClearSrc()
 		cmsg.pktinfo = unix.Inet6Pktinfo{}
+		end.Lock()
 		_, err = unix.SendmsgN(sock, buff, (*[unsafe.Sizeof(cmsg)]byte)(unsafe.Pointer(&cmsg))[:], end.dst6(), 0)
+		end.Unlock()
 	}
 
 	return err
@@ -541,7 +550,7 @@ func send6(sock int, end *NativeEndpoint, buff []byte) error {
 
 func receive4(sock int, buff []byte, end *NativeEndpoint) (int, error) {
 
-	// contruct message header
+	// construct message header
 
 	var cmsg struct {
 		cmsghdr unix.Cmsghdr
@@ -573,7 +582,7 @@ func receive4(sock int, buff []byte, end *NativeEndpoint) (int, error) {
 
 func receive6(sock int, buff []byte, end *NativeEndpoint) (int, error) {
 
-	// contruct message header
+	// construct message header
 
 	var cmsg struct {
 		cmsghdr unix.Cmsghdr

device/constants.go

@@ -12,7 +12,7 @@ import (
 /* Specification constants */
 
 const (
-	RekeyAfterMessages      = (1 << 64) - (1 << 16) - 1
+	RekeyAfterMessages      = (1 << 60)
 	RejectAfterMessages     = (1 << 64) - (1 << 4) - 1
 	RekeyAfterTime          = time.Second * 120
 	RekeyAttemptTime        = time.Second * 90

device/device_test.go

@@ -5,54 +5,212 @@
 
 package device
 
-/* Create two device instances and simulate full WireGuard interaction
- * without network dependencies
- */
-
 import (
+	"bufio"
 	"bytes"
+	"encoding/binary"
+	"io"
+	"net"
+	"os"
+	"strings"
 	"testing"
+	"time"
+
+	"golang.zx2c4.com/wireguard/tun"
 )
 
-func TestDevice(t *testing.T) {
+func TestTwoDevicePing(t *testing.T) {
-
+	// TODO(crawshaw): pick unused ports on localhost
-	// prepare tun devices for generating traffic
+	cfg1 := `private_key=481eb0d8113a4a5da532d2c3e9c14b53c8454b34ab109676f6b58c2245e37b58
-
+listen_port=53511
-	tun1 := newDummyTUN("tun1")
+replace_peers=true
-	tun2 := newDummyTUN("tun2")
+public_key=f70dbb6b1b92a1dde1c783b297016af3f572fef13b0abb16a2623d89a58e9725
-
+protocol_version=1
-	_ = tun1
+replace_allowed_ips=true
-	_ = tun2
+allowed_ip=1.0.0.2/32
-
+endpoint=127.0.0.1:53512`
-	// prepare endpoints
+	tun1 := NewChannelTUN()
-
+	dev1 := NewDevice(tun1.TUN(), NewLogger(LogLevelDebug, "dev1: "))
-	end1, err := CreateDummyEndpoint()
+	dev1.Up()
-	if err != nil {
+	defer dev1.Close()
-		t.Error("failed to create endpoint:", err.Error())
+	if err := dev1.IpcSetOperation(bufio.NewReader(strings.NewReader(cfg1))); err != nil {
-	}
-
-	end2, err := CreateDummyEndpoint()
-	if err != nil {
-		t.Error("failed to create endpoint:", err.Error())
-	}
-
-	_ = end1
-	_ = end2
-
-	// create binds
-
-}
-
-func randDevice(t *testing.T) *Device {
-	sk, err := newPrivateKey()
-	if err != nil {
 		t.Fatal(err)
 	}
-	tun := newDummyTUN("dummy")
+
-	logger := NewLogger(LogLevelError, "")
+	cfg2 := `private_key=98c7989b1661a0d64fd6af3502000f87716b7c4bbcf00d04fc6073aa7b539768
-	device := NewDevice(tun, logger)
+listen_port=53512
-	device.SetPrivateKey(sk)
+replace_peers=true
-	return device
+public_key=49e80929259cebdda4f322d6d2b1a6fad819d603acd26fd5d845e7a123036427
+protocol_version=1
+replace_allowed_ips=true
+allowed_ip=1.0.0.1/32
+endpoint=127.0.0.1:53511`
+	tun2 := NewChannelTUN()
+	dev2 := NewDevice(tun2.TUN(), NewLogger(LogLevelDebug, "dev2: "))
+	dev2.Up()
+	defer dev2.Close()
+	if err := dev2.IpcSetOperation(bufio.NewReader(strings.NewReader(cfg2))); err != nil {
+		t.Fatal(err)
+	}
+
+	t.Run("ping 1.0.0.1", func(t *testing.T) {
+		msg2to1 := ping(net.ParseIP("1.0.0.1"), net.ParseIP("1.0.0.2"))
+		tun2.Outbound <- msg2to1
+		select {
+		case msgRecv := <-tun1.Inbound:
+			if !bytes.Equal(msg2to1, msgRecv) {
+				t.Error("ping did not transit correctly")
+			}
+		case <-time.After(300 * time.Millisecond):
+			t.Error("ping did not transit")
+		}
+	})
+
+	t.Run("ping 1.0.0.2", func(t *testing.T) {
+		msg1to2 := ping(net.ParseIP("1.0.0.2"), net.ParseIP("1.0.0.1"))
+		tun1.Outbound <- msg1to2
+		select {
+		case msgRecv := <-tun2.Inbound:
+			if !bytes.Equal(msg1to2, msgRecv) {
+				t.Error("return ping did not transit correctly")
+			}
+		case <-time.After(300 * time.Millisecond):
+			t.Error("return ping did not transit")
+		}
+	})
+}
+
+func ping(dst, src net.IP) []byte {
+	localPort := uint16(1337)
+	seq := uint16(0)
+
+	payload := make([]byte, 4)
+	binary.BigEndian.PutUint16(payload[0:], localPort)
+	binary.BigEndian.PutUint16(payload[2:], seq)
+
+	return genICMPv4(payload, dst, src)
+}
+
+// checksum is the "internet checksum" from https://tools.ietf.org/html/rfc1071.
+func checksum(buf []byte, initial uint16) uint16 {
+	v := uint32(initial)
+	for i := 0; i < len(buf)-1; i += 2 {
+		v += uint32(binary.BigEndian.Uint16(buf[i:]))
+	}
+	if len(buf)%2 == 1 {
+		v += uint32(buf[len(buf)-1]) << 8
+	}
+	for v > 0xffff {
+		v = (v >> 16) + (v & 0xffff)
+	}
+	return ^uint16(v)
+}
+
+func genICMPv4(payload []byte, dst, src net.IP) []byte {
+	const (
+		icmpv4ProtocolNumber = 1
+		icmpv4Echo           = 8
+		icmpv4ChecksumOffset = 2
+		icmpv4Size           = 8
+		ipv4Size             = 20
+		ipv4TotalLenOffset   = 2
+		ipv4ChecksumOffset   = 10
+		ttl                  = 65
+	)
+
+	hdr := make([]byte, ipv4Size+icmpv4Size)
+
+	ip := hdr[0:ipv4Size]
+	icmpv4 := hdr[ipv4Size : ipv4Size+icmpv4Size]
+
+	// https://tools.ietf.org/html/rfc792
+	icmpv4[0] = icmpv4Echo // type
+	icmpv4[1] = 0          // code
+	chksum := ^checksum(icmpv4, checksum(payload, 0))
+	binary.BigEndian.PutUint16(icmpv4[icmpv4ChecksumOffset:], chksum)
+
+	// https://tools.ietf.org/html/rfc760 section 3.1
+	length := uint16(len(hdr) + len(payload))
+	ip[0] = (4 << 4) | (ipv4Size / 4)
+	binary.BigEndian.PutUint16(ip[ipv4TotalLenOffset:], length)
+	ip[8] = ttl
+	ip[9] = icmpv4ProtocolNumber
+	copy(ip[12:], src.To4())
+	copy(ip[16:], dst.To4())
+	chksum = ^checksum(ip[:], 0)
+	binary.BigEndian.PutUint16(ip[ipv4ChecksumOffset:], chksum)
+
+	var v []byte
+	v = append(v, hdr...)
+	v = append(v, payload...)
+	return []byte(v)
+}
+
+// TODO(crawshaw): find a reusable home for this. package devicetest?
+type ChannelTUN struct {
+	Inbound  chan []byte // incoming packets, closed on TUN close
+	Outbound chan []byte // outbound packets, blocks forever on TUN close
+
+	closed chan struct{}
+	events chan tun.Event
+	tun    chTun
+}
+
+func NewChannelTUN() *ChannelTUN {
+	c := &ChannelTUN{
+		Inbound:  make(chan []byte),
+		Outbound: make(chan []byte),
+		closed:   make(chan struct{}),
+		events:   make(chan tun.Event, 1),
+	}
+	c.tun.c = c
+	c.events <- tun.EventUp
+	return c
+}
+
+func (c *ChannelTUN) TUN() tun.Device {
+	return &c.tun
+}
+
+type chTun struct {
+	c *ChannelTUN
+}
+
+func (t *chTun) File() *os.File { return nil }
+
+func (t *chTun) Read(data []byte, offset int) (int, error) {
+	select {
+	case <-t.c.closed:
+		return 0, io.EOF // TODO(crawshaw): what is the correct error value?
+	case msg := <-t.c.Outbound:
+		return copy(data[offset:], msg), nil
+	}
+}
+
+// Write is called by the wireguard device to deliver a packet for routing.
+func (t *chTun) Write(data []byte, offset int) (int, error) {
+	if offset == -1 {
+		close(t.c.closed)
+		close(t.c.events)
+		return 0, io.EOF
+	}
+	msg := make([]byte, len(data)-offset)
+	copy(msg, data[offset:])
+	select {
+	case <-t.c.closed:
+		return 0, io.EOF // TODO(crawshaw): what is the correct error value?
+	case t.c.Inbound <- msg:
+		return len(data) - offset, nil
+	}
+}
+
+func (t *chTun) Flush() error           { return nil }
+func (t *chTun) MTU() (int, error)      { return DefaultMTU, nil }
+func (t *chTun) Name() (string, error)  { return "loopbackTun1", nil }
+func (t *chTun) Events() chan tun.Event { return t.c.events }
+func (t *chTun) Close() error {
+	t.Write(nil, -1)
+	return nil
 }
 
 func assertNil(t *testing.T, err error) {
@@ -66,3 +224,15 @@ func assertEqual(t *testing.T, a, b []byte) {
 		t.Fatal(a, "!=", b)
 	}
 }
+
+func randDevice(t *testing.T) *Device {
+	sk, err := newPrivateKey()
+	if err != nil {
+		t.Fatal(err)
+	}
+	tun := newDummyTUN("dummy")
+	logger := NewLogger(LogLevelError, "")
+	device := NewDevice(tun, logger)
+	device.SetPrivateKey(sk)
+	return device
+}

device/noise-protocol.go

@@ -39,13 +39,13 @@ const (
 )
 
 const (
-	MessageInitiationSize      = 148                                           // size of handshake initation message
+	MessageInitiationSize      = 148                                           // size of handshake initiation message
 	MessageResponseSize        = 92                                            // size of response message
 	MessageCookieReplySize     = 64                                            // size of cookie reply message
-	MessageTransportHeaderSize = 16                                            // size of data preceeding content in transport message
+	MessageTransportHeaderSize = 16                                            // size of data preceding content in transport message
 	MessageTransportSize       = MessageTransportHeaderSize + poly1305.TagSize // size of empty transport
 	MessageKeepaliveSize       = MessageTransportSize                          // size of keepalive
-	MessageHandshakeSize       = MessageInitiationSize                         // size of largest handshake releated message
+	MessageHandshakeSize       = MessageInitiationSize                         // size of largest handshake related message
 )
 
 const (
@@ -315,8 +315,13 @@ func (device *Device) ConsumeMessageInitiation(msg *MessageInitiation) *Peer {
 	handshake.chainKey = chainKey
 	handshake.remoteIndex = msg.Sender
 	handshake.remoteEphemeral = msg.Ephemeral
-	handshake.lastTimestamp = timestamp
+	if timestamp.After(handshake.lastTimestamp) {
-	handshake.lastInitiationConsumption = time.Now()
+		handshake.lastTimestamp = timestamp
+	}
+	now := time.Now()
+	if now.After(handshake.lastInitiationConsumption) {
+		handshake.lastInitiationConsumption = now
+	}
 	handshake.state = HandshakeInitiationConsumed
 
 	handshake.mutex.Unlock()

device/send.go

@@ -220,10 +220,7 @@ func (device *Device) SendHandshakeCookie(initiatingElem *QueueHandshakeElement)
 	writer := bytes.NewBuffer(buff[:0])
 	binary.Write(writer, binary.LittleEndian, reply)
 	device.net.bind.Send(writer.Bytes(), initiatingElem.endpoint)
-	if err != nil {
+	return nil
-		device.log.Error.Println("Failed to send cookie reply:", err)
-	}
-	return err
 }
 
 func (peer *Peer) keepKeyFreshSending() {

device/version.go

@@ -1,3 +1,3 @@
 package device
 
-const WireGuardGoVersion = "0.0.20191012"
+const WireGuardGoVersion = "0.0.20200121"

main_windows.go

@@ -37,7 +37,7 @@ func main() {
 	logger.Info.Println("Starting wireguard-go version", device.WireGuardGoVersion)
 	logger.Debug.Println("Debug log enabled")
 
-	tun, err := tun.CreateTUN(interfaceName)
+	tun, err := tun.CreateTUN(interfaceName, 0)
 	if err == nil {
 		realInterfaceName, err2 := tun.Name()
 		if err2 == nil {

ratelimiter/ratelimiter_test.go

@@ -36,7 +36,7 @@ func TestRatelimiter(t *testing.T) {
 	for i := 0; i < packetsBurstable; i++ {
 		Add(RatelimiterResult{
 			allowed: true,
-			text:    "inital burst",
+			text:    "initial burst",
 		})
 	}
 

rwcancel/rwcancel.go

@@ -60,7 +60,13 @@ func (rw *RWCancel) ReadyRead() bool {
 	fdset := fdSet{}
 	fdset.set(rw.fd)
 	fdset.set(closeFd)
-	err := unixSelect(max(rw.fd, closeFd)+1, &fdset.FdSet, nil, nil, nil)
+	var err error
+	for {
+		err = unixSelect(max(rw.fd, closeFd)+1, &fdset.FdSet, nil, nil, nil)
+		if err == nil || !RetryAfterError(err) {
+			break
+		}
+	}
 	if err != nil {
 		return false
 	}
@@ -75,7 +81,13 @@ func (rw *RWCancel) ReadyWrite() bool {
 	fdset := fdSet{}
 	fdset.set(rw.fd)
 	fdset.set(closeFd)
-	err := unixSelect(max(rw.fd, closeFd)+1, nil, &fdset.FdSet, nil, nil)
+	var err error
+	for {
+		err = unixSelect(max(rw.fd, closeFd)+1, nil, &fdset.FdSet, nil, nil)
+		if err == nil || !RetryAfterError(err) {
+			break
+		}
+	}
 	if err != nil {
 		return false
 	}

tun/tun_darwin.go

@@ -11,6 +11,7 @@ import (
 	"net"
 	"os"
 	"syscall"
+	"time"
 	"unsafe"
 
 	"golang.org/x/net/ipv6"
@@ -42,6 +43,22 @@ type NativeTun struct {
 
 var sockaddrCtlSize uintptr = 32
 
+func retryInterfaceByIndex(index int) (iface *net.Interface, err error) {
+	for i := 0; i < 20; i++ {
+		iface, err = net.InterfaceByIndex(index)
+		if err != nil {
+			if opErr, ok := err.(*net.OpError); ok {
+				if syscallErr, ok := opErr.Err.(*os.SyscallError); ok && syscallErr.Err == syscall.ENOMEM {
+					time.Sleep(time.Duration(i) * time.Second / 3)
+					continue
+				}
+			}
+		}
+		return iface, err
+	}
+	return nil, err
+}
+
 func (tun *NativeTun) routineRouteListener(tunIfindex int) {
 	var (
 		statusUp  bool
@@ -74,7 +91,7 @@ func (tun *NativeTun) routineRouteListener(tunIfindex int) {
 			continue
 		}
 
-		iface, err := net.InterfaceByIndex(ifindex)
+		iface, err := retryInterfaceByIndex(ifindex)
 		if err != nil {
 			tun.errors <- err
 			return

tun/tun_linux.go

@@ -35,7 +35,7 @@ type NativeTun struct {
 	name                    string     // name of interface
 	errors                  chan error // async error handling
 	events                  chan Event // device related events
-	nopi                    bool       // the device was pased IFF_NO_PI
+	nopi                    bool       // the device was passed IFF_NO_PI
 	netlinkSock             int
 	netlinkCancel           *rwcancel.RWCancel
 	hackListenerClosed      sync.Mutex

tun/tun_windows.go

@@ -9,6 +9,7 @@ import (
 	"errors"
 	"fmt"
 	"os"
+	"sync"
 	"sync/atomic"
 	"time"
 	"unsafe"
@@ -35,11 +36,12 @@ type NativeTun struct {
 	wt        *wintun.Interface
 	handle    windows.Handle
 	close     bool
-	rings     wintun.RingDescriptor
 	events    chan Event
 	errors    chan error
 	forcedMTU int
 	rate      rateJuggler
+	rings     *wintun.RingDescriptor
+	writeLock sync.Mutex
 }
 
 const WintunPool = wintun.Pool("WireGuard")
@@ -54,15 +56,15 @@ func nanotime() int64
 // CreateTUN creates a Wintun interface with the given name. Should a Wintun
 // interface with the same name exist, it is reused.
 //
-func CreateTUN(ifname string) (Device, error) {
+func CreateTUN(ifname string, mtu int) (Device, error) {
-	return CreateTUNWithRequestedGUID(ifname, nil)
+	return CreateTUNWithRequestedGUID(ifname, nil, mtu)
 }
 
 //
 // CreateTUNWithRequestedGUID creates a Wintun interface with the given name and
 // a requested GUID. Should a Wintun interface with the same name exist, it is reused.
 //
-func CreateTUNWithRequestedGUID(ifname string, requestedGUID *windows.GUID) (Device, error) {
+func CreateTUNWithRequestedGUID(ifname string, requestedGUID *windows.GUID, mtu int) (Device, error) {
 	var err error
 	var wt *wintun.Interface
 
@@ -80,21 +82,26 @@ func CreateTUNWithRequestedGUID(ifname string, requestedGUID *windows.GUID) (Dev
 		return nil, fmt.Errorf("Error creating interface: %v", err)
 	}
 
+	forcedMTU := 1420
+	if mtu > 0 {
+		forcedMTU = mtu
+	}
+
 	tun := &NativeTun{
 		wt:        wt,
 		handle:    windows.InvalidHandle,
 		events:    make(chan Event, 10),
 		errors:    make(chan error, 1),
-		forcedMTU: 1500,
+		forcedMTU: forcedMTU,
 	}
 
-	err = tun.rings.Init()
+	tun.rings, err = wintun.NewRingDescriptor()
 	if err != nil {
 		tun.Close()
 		return nil, fmt.Errorf("Error creating events: %v", err)
 	}
 
-	tun.handle, err = tun.wt.Register(&tun.rings)
+	tun.handle, err = tun.wt.Register(tun.rings)
 	if err != nil {
 		tun.Close()
 		return nil, fmt.Errorf("Error registering rings: %v", err)
@@ -214,6 +221,9 @@ func (tun *NativeTun) Write(buff []byte, offset int) (int, error) {
 	tun.rate.update(uint64(packetSize))
 	alignedPacketSize := wintun.PacketAlign(uint32(unsafe.Sizeof(wintun.PacketHeader{})) + packetSize)
 
+	tun.writeLock.Lock()
+	defer tun.writeLock.Unlock()
+
 	buffHead := atomic.LoadUint32(&tun.rings.Receive.Ring.Head)
 	if buffHead >= wintun.PacketCapacity {
 		return 0, os.ErrClosed

tun/wintun/namespaceapi/namespaceapi_windows.go

@@ -40,7 +40,7 @@ func (bd *BoundaryDescriptor) AddSid(requiredSid *windows.SID) error {
 	return addSIDToBoundaryDescriptor((*windows.Handle)(bd), requiredSid)
 }
 
-// PrivateNamespace represents a private namespace. Duh?!
+// PrivateNamespace represents a private namespace.
 type PrivateNamespace windows.Handle
 
 // CreatePrivateNamespace creates a private namespace.

tun/wintun/ring_windows.go

@@ -6,6 +6,7 @@
 package wintun
 
 import (
+	"runtime"
 	"unsafe"
 
 	"golang.org/x/sys/windows"
@@ -53,25 +54,44 @@ func PacketAlign(size uint32) uint32 {
 	return (size + (PacketAlignment - 1)) &^ (PacketAlignment - 1)
 }
 
-func (descriptor *RingDescriptor) Init() (err error) {
+func NewRingDescriptor() (descriptor *RingDescriptor, err error) {
+	descriptor = new(RingDescriptor)
+	allocatedRegion, err := windows.VirtualAlloc(0, unsafe.Sizeof(Ring{})*2, windows.MEM_COMMIT|windows.MEM_RESERVE, windows.PAGE_READWRITE)
+	if err != nil {
+		return
+	}
+	defer func() {
+		if err != nil {
+			descriptor.free()
+			descriptor = nil
+		}
+	}()
 	descriptor.Send.Size = uint32(unsafe.Sizeof(Ring{}))
-	descriptor.Send.Ring = &Ring{}
+	descriptor.Send.Ring = (*Ring)(unsafe.Pointer(allocatedRegion))
 	descriptor.Send.TailMoved, err = windows.CreateEvent(nil, 0, 0, nil)
 	if err != nil {
 		return
 	}
 
 	descriptor.Receive.Size = uint32(unsafe.Sizeof(Ring{}))
-	descriptor.Receive.Ring = &Ring{}
+	descriptor.Receive.Ring = (*Ring)(unsafe.Pointer(allocatedRegion + unsafe.Sizeof(Ring{})))
 	descriptor.Receive.TailMoved, err = windows.CreateEvent(nil, 0, 0, nil)
 	if err != nil {
 		windows.CloseHandle(descriptor.Send.TailMoved)
 		return
 	}
-
+	runtime.SetFinalizer(descriptor, func(d *RingDescriptor) { d.free() })
 	return
 }
 
+func (descriptor *RingDescriptor) free() {
+	if descriptor.Send.Ring != nil {
+		windows.VirtualFree(uintptr(unsafe.Pointer(descriptor.Send.Ring)), 0, windows.MEM_RELEASE)
+		descriptor.Send.Ring = nil
+		descriptor.Receive.Ring = nil
+	}
+}
+
 func (descriptor *RingDescriptor) Close() {
 	if descriptor.Send.TailMoved != 0 {
 		windows.CloseHandle(descriptor.Send.TailMoved)

tun/wintun/setupapi/types_windows.go

@@ -57,7 +57,7 @@ type DevInfoData struct {
 	_         uintptr
 }
 
-// DevInfoListDetailData is a structure for detailed information on a device information set (used for SetupDiGetDeviceInfoListDetail which supercedes the functionality of SetupDiGetDeviceInfoListClass).
+// DevInfoListDetailData is a structure for detailed information on a device information set (used for SetupDiGetDeviceInfoListDetail which supersedes the functionality of SetupDiGetDeviceInfoListClass).
 type DevInfoListDetailData struct {
 	size                uint32 // Warning: unsafe.Sizeof(DevInfoListDetailData) > sizeof(SP_DEVINFO_LIST_DETAIL_DATA) when GOARCH == 386 => use sizeofDevInfoListDetailData const.
 	ClassGUID           windows.GUID

tun/wintun/wintun_windows.go

@@ -40,9 +40,9 @@ const (
 )
 
 // makeWintun creates a Wintun interface handle and populates it from the device's registry key.
-func makeWintun(deviceInfoSet setupapi.DevInfo, deviceInfoData *setupapi.DevInfoData, pool Pool) (*Interface, error) {
+func makeWintun(devInfo setupapi.DevInfo, devInfoData *setupapi.DevInfoData, pool Pool) (*Interface, error) {
 	// Open HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\<class>\<id> registry key.
-	key, err := deviceInfoSet.OpenDevRegKey(deviceInfoData, setupapi.DICS_FLAG_GLOBAL, 0, setupapi.DIREG_DRV, registry.QUERY_VALUE)
+	key, err := devInfo.OpenDevRegKey(devInfoData, setupapi.DICS_FLAG_GLOBAL, 0, setupapi.DIREG_DRV, registry.QUERY_VALUE)
 	if err != nil {
 		return nil, fmt.Errorf("Device-specific registry key open failed: %v", err)
 	}
@@ -72,7 +72,7 @@ func makeWintun(deviceInfoSet setupapi.DevInfo, deviceInfoData *setupapi.DevInfo
 		return nil, fmt.Errorf("RegQueryValue(\"*IfType\") failed: %v", err)
 	}
 
-	instanceID, err := deviceInfoSet.DeviceInstanceID(deviceInfoData)
+	instanceID, err := devInfo.DeviceInstanceID(devInfoData)
 	if err != nil {
 		return nil, fmt.Errorf("DeviceInstanceID failed: %v", err)
 	}
@@ -109,11 +109,11 @@ func (pool Pool) GetInterface(ifname string) (*Interface, error) {
 	}()
 
 	// Create a list of network devices.
-	devInfoList, err := setupapi.SetupDiGetClassDevsEx(&deviceClassNetGUID, "", 0, setupapi.DIGCF_PRESENT, setupapi.DevInfo(0), "")
+	devInfo, err := setupapi.SetupDiGetClassDevsEx(&deviceClassNetGUID, "", 0, setupapi.DIGCF_PRESENT, setupapi.DevInfo(0), "")
 	if err != nil {
 		return nil, fmt.Errorf("SetupDiGetClassDevsEx(%v) failed: %v", deviceClassNetGUID, err)
 	}
-	defer devInfoList.Close()
+	defer devInfo.Close()
 
 	// Windows requires each interface to have a different name. When
 	// enforcing this, Windows treats interface names case-insensitive. If an
@@ -123,7 +123,7 @@ func (pool Pool) GetInterface(ifname string) (*Interface, error) {
 	ifname = strings.ToLower(ifname)
 
 	for index := 0; ; index++ {
-		deviceData, err := devInfoList.EnumDeviceInfo(index)
+		devInfoData, err := devInfo.EnumDeviceInfo(index)
 		if err != nil {
 			if err == windows.ERROR_NO_MORE_ITEMS {
 				break
@@ -131,7 +131,16 @@ func (pool Pool) GetInterface(ifname string) (*Interface, error) {
 			continue
 		}
 
-		wintun, err := makeWintun(devInfoList, deviceData, pool)
+		// Check the Hardware ID to make sure it's a real Wintun device first. This avoids doing slow operations on non-Wintun devices.
+		property, err := devInfo.DeviceRegistryProperty(devInfoData, setupapi.SPDRP_HARDWAREID)
+		if err != nil {
+			continue
+		}
+		if hwids, ok := property.([]string); ok && len(hwids) > 0 && hwids[0] != hardwareID {
+			continue
+		}
+
+		wintun, err := makeWintun(devInfo, devInfoData, pool)
 		if err != nil {
 			continue
 		}
@@ -145,14 +154,14 @@ func (pool Pool) GetInterface(ifname string) (*Interface, error) {
 		ifname3 := removeNumberedSuffix(ifname2)
 
 		if ifname == ifname2 || ifname == ifname3 {
-			err = devInfoList.BuildDriverInfoList(deviceData, setupapi.SPDIT_COMPATDRIVER)
+			err = devInfo.BuildDriverInfoList(devInfoData, setupapi.SPDIT_COMPATDRIVER)
 			if err != nil {
 				return nil, fmt.Errorf("SetupDiBuildDriverInfoList failed: %v", err)
 			}
-			defer devInfoList.DestroyDriverInfoList(deviceData, setupapi.SPDIT_COMPATDRIVER)
+			defer devInfo.DestroyDriverInfoList(devInfoData, setupapi.SPDIT_COMPATDRIVER)
 
 			for index := 0; ; index++ {
-				driverData, err := devInfoList.EnumDriverInfo(deviceData, setupapi.SPDIT_COMPATDRIVER, index)
+				driverData, err := devInfo.EnumDriverInfo(devInfoData, setupapi.SPDIT_COMPATDRIVER, index)
 				if err != nil {
 					if err == windows.ERROR_NO_MORE_ITEMS {
 						break
@@ -161,13 +170,13 @@ func (pool Pool) GetInterface(ifname string) (*Interface, error) {
 				}
 
 				// Get driver info details.
-				driverDetailData, err := devInfoList.DriverInfoDetail(deviceData, driverData)
+				driverDetailData, err := devInfo.DriverInfoDetail(devInfoData, driverData)
 				if err != nil {
 					continue
 				}
 
 				if driverDetailData.IsCompatible(hardwareID) {
-					isMember, err := pool.isMember(devInfoList, deviceData)
+					isMember, err := pool.isMember(devInfo, devInfoData)
 					if err != nil {
 						return nil, err
 					}
@@ -206,12 +215,12 @@ func (pool Pool) CreateInterface(ifname string, requestedGUID *windows.GUID) (wi
 	}()
 
 	// Create an empty device info set for network adapter device class.
-	devInfoList, err := setupapi.SetupDiCreateDeviceInfoListEx(&deviceClassNetGUID, 0, "")
+	devInfo, err := setupapi.SetupDiCreateDeviceInfoListEx(&deviceClassNetGUID, 0, "")
 	if err != nil {
 		err = fmt.Errorf("SetupDiCreateDeviceInfoListEx(%v) failed: %v", deviceClassNetGUID, err)
 		return
 	}
-	defer devInfoList.Close()
+	defer devInfo.Close()
 
 	// Get the device class name from GUID.
 	className, err := setupapi.SetupDiClassNameFromGuidEx(&deviceClassNetGUID, "")
@@ -222,43 +231,43 @@ func (pool Pool) CreateInterface(ifname string, requestedGUID *windows.GUID) (wi
 
 	// Create a new device info element and add it to the device info set.
 	deviceTypeName := pool.deviceTypeName()
-	deviceData, err := devInfoList.CreateDeviceInfo(className, &deviceClassNetGUID, deviceTypeName, 0, setupapi.DICD_GENERATE_ID)
+	devInfoData, err := devInfo.CreateDeviceInfo(className, &deviceClassNetGUID, deviceTypeName, 0, setupapi.DICD_GENERATE_ID)
 	if err != nil {
 		err = fmt.Errorf("SetupDiCreateDeviceInfo failed: %v", err)
 		return
 	}
 
-	err = setQuietInstall(devInfoList, deviceData)
+	err = setQuietInstall(devInfo, devInfoData)
 	if err != nil {
 		err = fmt.Errorf("Setting quiet installation failed: %v", err)
 		return
 	}
 
 	// Set a device information element as the selected member of a device information set.
-	err = devInfoList.SetSelectedDevice(deviceData)
+	err = devInfo.SetSelectedDevice(devInfoData)
 	if err != nil {
 		err = fmt.Errorf("SetupDiSetSelectedDevice failed: %v", err)
 		return
 	}
 
 	// Set Plug&Play device hardware ID property.
-	err = devInfoList.SetDeviceRegistryPropertyString(deviceData, setupapi.SPDRP_HARDWAREID, hardwareID)
+	err = devInfo.SetDeviceRegistryPropertyString(devInfoData, setupapi.SPDRP_HARDWAREID, hardwareID)
 	if err != nil {
 		err = fmt.Errorf("SetupDiSetDeviceRegistryProperty(SPDRP_HARDWAREID) failed: %v", err)
 		return
 	}
 
-	err = devInfoList.BuildDriverInfoList(deviceData, setupapi.SPDIT_COMPATDRIVER) // TODO: This takes ~510ms
+	err = devInfo.BuildDriverInfoList(devInfoData, setupapi.SPDIT_COMPATDRIVER) // TODO: This takes ~510ms
 	if err != nil {
 		err = fmt.Errorf("SetupDiBuildDriverInfoList failed: %v", err)
 		return
 	}
-	defer devInfoList.DestroyDriverInfoList(deviceData, setupapi.SPDIT_COMPATDRIVER)
+	defer devInfo.DestroyDriverInfoList(devInfoData, setupapi.SPDIT_COMPATDRIVER)
 
 	driverDate := windows.Filetime{}
 	driverVersion := uint64(0)
 	for index := 0; ; index++ { // TODO: This loop takes ~600ms
-		driverData, err := devInfoList.EnumDriverInfo(deviceData, setupapi.SPDIT_COMPATDRIVER, index)
+		driverData, err := devInfo.EnumDriverInfo(devInfoData, setupapi.SPDIT_COMPATDRIVER, index)
 		if err != nil {
 			if err == windows.ERROR_NO_MORE_ITEMS {
 				break
@@ -268,13 +277,13 @@ func (pool Pool) CreateInterface(ifname string, requestedGUID *windows.GUID) (wi
 
 		// Check the driver version first, since the check is trivial and will save us iterating over hardware IDs for any driver versioned prior our best match.
 		if driverData.IsNewer(driverDate, driverVersion) {
-			driverDetailData, err := devInfoList.DriverInfoDetail(deviceData, driverData)
+			driverDetailData, err := devInfo.DriverInfoDetail(devInfoData, driverData)
 			if err != nil {
 				continue
 			}
 
 			if driverDetailData.IsCompatible(hardwareID) {
-				err := devInfoList.SetSelectedDriver(deviceData, driverData)
+				err := devInfo.SetSelectedDriver(devInfoData, driverData)
 				if err != nil {
 					continue
 				}
@@ -299,10 +308,10 @@ func (pool Pool) CreateInterface(ifname string, requestedGUID *windows.GUID) (wi
 			}
 
 			// Set class installer parameters for DIF_REMOVE.
-			if devInfoList.SetClassInstallParams(deviceData, &removeDeviceParams.ClassInstallHeader, uint32(unsafe.Sizeof(removeDeviceParams))) == nil {
+			if devInfo.SetClassInstallParams(devInfoData, &removeDeviceParams.ClassInstallHeader, uint32(unsafe.Sizeof(removeDeviceParams))) == nil {
 				// Call appropriate class installer.
-				if devInfoList.CallClassInstaller(setupapi.DIF_REMOVE, deviceData) == nil {
+				if devInfo.CallClassInstaller(setupapi.DIF_REMOVE, devInfoData) == nil {
-					rebootRequired = rebootRequired || checkReboot(devInfoList, deviceData)
+					rebootRequired = rebootRequired || checkReboot(devInfo, devInfoData)
 				}
 			}
 
@@ -311,14 +320,14 @@ func (pool Pool) CreateInterface(ifname string, requestedGUID *windows.GUID) (wi
 	}()
 
 	// Call appropriate class installer.
-	err = devInfoList.CallClassInstaller(setupapi.DIF_REGISTERDEVICE, deviceData)
+	err = devInfo.CallClassInstaller(setupapi.DIF_REGISTERDEVICE, devInfoData)
 	if err != nil {
 		err = fmt.Errorf("SetupDiCallClassInstaller(DIF_REGISTERDEVICE) failed: %v", err)
 		return
 	}
 
 	// Register device co-installers if any. (Ignore errors)
-	devInfoList.CallClassInstaller(setupapi.DIF_REGISTER_COINSTALLERS, deviceData)
+	devInfo.CallClassInstaller(setupapi.DIF_REGISTER_COINSTALLERS, devInfoData)
 
 	var netDevRegKey registry.Key
 	const pollTimeout = time.Millisecond * 50
@@ -326,7 +335,7 @@ func (pool Pool) CreateInterface(ifname string, requestedGUID *windows.GUID) (wi
 		if i != 0 {
 			time.Sleep(pollTimeout)
 		}
-		netDevRegKey, err = devInfoList.OpenDevRegKey(deviceData, setupapi.DICS_FLAG_GLOBAL, 0, setupapi.DIREG_DRV, registry.SET_VALUE|registry.QUERY_VALUE|registry.NOTIFY)
+		netDevRegKey, err = devInfo.OpenDevRegKey(devInfoData, setupapi.DICS_FLAG_GLOBAL, 0, setupapi.DIREG_DRV, registry.SET_VALUE|registry.QUERY_VALUE|registry.NOTIFY)
 		if err == nil {
 			break
 		}
@@ -345,17 +354,17 @@ func (pool Pool) CreateInterface(ifname string, requestedGUID *windows.GUID) (wi
 	}
 
 	// Install interfaces if any. (Ignore errors)
-	devInfoList.CallClassInstaller(setupapi.DIF_INSTALLINTERFACES, deviceData)
+	devInfo.CallClassInstaller(setupapi.DIF_INSTALLINTERFACES, devInfoData)
 
 	// Install the device.
-	err = devInfoList.CallClassInstaller(setupapi.DIF_INSTALLDEVICE, deviceData)
+	err = devInfo.CallClassInstaller(setupapi.DIF_INSTALLDEVICE, devInfoData)
 	if err != nil {
 		err = fmt.Errorf("SetupDiCallClassInstaller(DIF_INSTALLDEVICE) failed: %v", err)
 		return
 	}
-	rebootRequired = checkReboot(devInfoList, deviceData)
+	rebootRequired = checkReboot(devInfo, devInfoData)
 
-	err = devInfoList.SetDeviceRegistryPropertyString(deviceData, setupapi.SPDRP_DEVICEDESC, deviceTypeName)
+	err = devInfo.SetDeviceRegistryPropertyString(devInfoData, setupapi.SPDRP_DEVICEDESC, deviceTypeName)
 	if err != nil {
 		err = fmt.Errorf("SetDeviceRegistryPropertyString(SPDRP_DEVICEDESC) failed: %v", err)
 		return
@@ -381,7 +390,7 @@ func (pool Pool) CreateInterface(ifname string, requestedGUID *windows.GUID) (wi
 	}
 
 	// Get network interface.
-	wintun, err = makeWintun(devInfoList, deviceData, pool)
+	wintun, err = makeWintun(devInfo, devInfoData, pool)
 	if err != nil {
 		err = fmt.Errorf("makeWintun failed: %v", err)
 		return
@@ -435,14 +444,14 @@ func (pool Pool) CreateInterface(ifname string, requestedGUID *windows.GUID) (wi
 // if the interface was not found. It returns a bool indicating whether
 // a reboot is required.
 func (wintun *Interface) DeleteInterface() (rebootRequired bool, err error) {
-	devInfoList, deviceData, err := wintun.deviceData()
+	devInfo, devInfoData, err := wintun.devInfoData()
 	if err == windows.ERROR_OBJECT_NOT_FOUND {
 		return false, nil
 	}
 	if err != nil {
 		return false, err
 	}
-	defer devInfoList.Close()
+	defer devInfo.Close()
 
 	// Remove the device.
 	removeDeviceParams := setupapi.RemoveDeviceParams{
@@ -451,18 +460,18 @@ func (wintun *Interface) DeleteInterface() (rebootRequired bool, err error) {
 	}
 
 	// Set class installer parameters for DIF_REMOVE.
-	err = devInfoList.SetClassInstallParams(deviceData, &removeDeviceParams.ClassInstallHeader, uint32(unsafe.Sizeof(removeDeviceParams)))
+	err = devInfo.SetClassInstallParams(devInfoData, &removeDeviceParams.ClassInstallHeader, uint32(unsafe.Sizeof(removeDeviceParams)))
 	if err != nil {
 		return false, fmt.Errorf("SetupDiSetClassInstallParams failed: %v", err)
 	}
 
 	// Call appropriate class installer.
-	err = devInfoList.CallClassInstaller(setupapi.DIF_REMOVE, deviceData)
+	err = devInfo.CallClassInstaller(setupapi.DIF_REMOVE, devInfoData)
 	if err != nil {
 		return false, fmt.Errorf("SetupDiCallClassInstaller failed: %v", err)
 	}
 
-	return checkReboot(devInfoList, deviceData), nil
+	return checkReboot(devInfo, devInfoData), nil
 }
 
 // DeleteMatchingInterfaces deletes all Wintun interfaces, which match
@@ -479,14 +488,14 @@ func (pool Pool) DeleteMatchingInterfaces(matches func(wintun *Interface) bool)
 		windows.CloseHandle(mutex)
 	}()
 
-	devInfoList, err := setupapi.SetupDiGetClassDevsEx(&deviceClassNetGUID, "", 0, setupapi.DIGCF_PRESENT, setupapi.DevInfo(0), "")
+	devInfo, err := setupapi.SetupDiGetClassDevsEx(&deviceClassNetGUID, "", 0, setupapi.DIGCF_PRESENT, setupapi.DevInfo(0), "")
 	if err != nil {
 		return nil, false, []error{fmt.Errorf("SetupDiGetClassDevsEx(%v) failed: %v", deviceClassNetGUID, err.Error())}
 	}
-	defer devInfoList.Close()
+	defer devInfo.Close()
 
 	for i := 0; ; i++ {
-		deviceData, err := devInfoList.EnumDeviceInfo(i)
+		devInfoData, err := devInfo.EnumDeviceInfo(i)
 		if err != nil {
 			if err == windows.ERROR_NO_MORE_ITEMS {
 				break
@@ -494,22 +503,31 @@ func (pool Pool) DeleteMatchingInterfaces(matches func(wintun *Interface) bool)
 			continue
 		}
 
-		err = devInfoList.BuildDriverInfoList(deviceData, setupapi.SPDIT_COMPATDRIVER)
+		// Check the Hardware ID to make sure it's a real Wintun device first. This avoids doing slow operations on non-Wintun devices.
+		property, err := devInfo.DeviceRegistryProperty(devInfoData, setupapi.SPDRP_HARDWAREID)
 		if err != nil {
 			continue
 		}
-		defer devInfoList.DestroyDriverInfoList(deviceData, setupapi.SPDIT_COMPATDRIVER)
+		if hwids, ok := property.([]string); ok && len(hwids) > 0 && hwids[0] != hardwareID {
+			continue
+		}
+
+		err = devInfo.BuildDriverInfoList(devInfoData, setupapi.SPDIT_COMPATDRIVER)
+		if err != nil {
+			continue
+		}
+		defer devInfo.DestroyDriverInfoList(devInfoData, setupapi.SPDIT_COMPATDRIVER)
 
 		isWintun := false
 		for j := 0; ; j++ {
-			driverData, err := devInfoList.EnumDriverInfo(deviceData, setupapi.SPDIT_COMPATDRIVER, j)
+			driverData, err := devInfo.EnumDriverInfo(devInfoData, setupapi.SPDIT_COMPATDRIVER, j)
 			if err != nil {
 				if err == windows.ERROR_NO_MORE_ITEMS {
 					break
 				}
 				continue
 			}
-			driverDetailData, err := devInfoList.DriverInfoDetail(deviceData, driverData)
+			driverDetailData, err := devInfo.DriverInfoDetail(devInfoData, driverData)
 			if err != nil {
 				continue
 			}
@@ -522,7 +540,7 @@ func (pool Pool) DeleteMatchingInterfaces(matches func(wintun *Interface) bool)
 			continue
 		}
 
-		isMember, err := pool.isMember(devInfoList, deviceData)
+		isMember, err := pool.isMember(devInfo, devInfoData)
 		if err != nil {
 			errors = append(errors, err)
 			continue
@@ -531,7 +549,7 @@ func (pool Pool) DeleteMatchingInterfaces(matches func(wintun *Interface) bool)
 			continue
 		}
 
-		wintun, err := makeWintun(devInfoList, deviceData, pool)
+		wintun, err := makeWintun(devInfo, devInfoData, pool)
 		if err != nil {
 			errors = append(errors, fmt.Errorf("Unable to make Wintun interface object: %v", err))
 			continue
@@ -540,41 +558,41 @@ func (pool Pool) DeleteMatchingInterfaces(matches func(wintun *Interface) bool)
 			continue
 		}
 
-		err = setQuietInstall(devInfoList, deviceData)
+		err = setQuietInstall(devInfo, devInfoData)
 		if err != nil {
 			errors = append(errors, err)
 			continue
 		}
 
-		inst := deviceData.DevInst
+		inst := devInfoData.DevInst
 		removeDeviceParams := setupapi.RemoveDeviceParams{
 			ClassInstallHeader: *setupapi.MakeClassInstallHeader(setupapi.DIF_REMOVE),
 			Scope:              setupapi.DI_REMOVEDEVICE_GLOBAL,
 		}
-		err = devInfoList.SetClassInstallParams(deviceData, &removeDeviceParams.ClassInstallHeader, uint32(unsafe.Sizeof(removeDeviceParams)))
+		err = devInfo.SetClassInstallParams(devInfoData, &removeDeviceParams.ClassInstallHeader, uint32(unsafe.Sizeof(removeDeviceParams)))
 		if err != nil {
 			errors = append(errors, err)
 			continue
 		}
-		err = devInfoList.CallClassInstaller(setupapi.DIF_REMOVE, deviceData)
+		err = devInfo.CallClassInstaller(setupapi.DIF_REMOVE, devInfoData)
 		if err != nil {
 			errors = append(errors, err)
 			continue
 		}
-		rebootRequired = rebootRequired || checkReboot(devInfoList, deviceData)
+		rebootRequired = rebootRequired || checkReboot(devInfo, devInfoData)
 		deviceInstancesDeleted = append(deviceInstancesDeleted, inst)
 	}
 	return
 }
 
 // isMember checks if SPDRP_DEVICEDESC or SPDRP_FRIENDLYNAME match device type name.
-func (pool Pool) isMember(deviceInfoSet setupapi.DevInfo, deviceInfoData *setupapi.DevInfoData) (bool, error) {
+func (pool Pool) isMember(devInfo setupapi.DevInfo, devInfoData *setupapi.DevInfoData) (bool, error) {
-	deviceDescVal, err := deviceInfoSet.DeviceRegistryProperty(deviceInfoData, setupapi.SPDRP_DEVICEDESC)
+	deviceDescVal, err := devInfo.DeviceRegistryProperty(devInfoData, setupapi.SPDRP_DEVICEDESC)
 	if err != nil {
 		return false, fmt.Errorf("DeviceRegistryPropertyString(SPDRP_DEVICEDESC) failed: %v", err)
 	}
 	deviceDesc, _ := deviceDescVal.(string)
-	friendlyNameVal, err := deviceInfoSet.DeviceRegistryProperty(deviceInfoData, setupapi.SPDRP_FRIENDLYNAME)
+	friendlyNameVal, err := devInfo.DeviceRegistryProperty(devInfoData, setupapi.SPDRP_FRIENDLYNAME)
 	if err != nil {
 		return false, fmt.Errorf("DeviceRegistryPropertyString(SPDRP_FRIENDLYNAME) failed: %v", err)
 	}
@@ -585,8 +603,8 @@ func (pool Pool) isMember(deviceInfoSet setupapi.DevInfo, deviceInfoData *setupa
 }
 
 // checkReboot checks device install parameters if a system reboot is required.
-func checkReboot(deviceInfoSet setupapi.DevInfo, deviceInfoData *setupapi.DevInfoData) bool {
+func checkReboot(devInfo setupapi.DevInfo, devInfoData *setupapi.DevInfoData) bool {
-	devInstallParams, err := deviceInfoSet.DeviceInstallParams(deviceInfoData)
+	devInstallParams, err := devInfo.DeviceInstallParams(devInfoData)
 	if err != nil {
 		return false
 	}
@@ -595,14 +613,14 @@ func checkReboot(deviceInfoSet setupapi.DevInfo, deviceInfoData *setupapi.DevInf
 }
 
 // setQuietInstall sets device install parameters for a quiet installation
-func setQuietInstall(deviceInfoSet setupapi.DevInfo, deviceInfoData *setupapi.DevInfoData) error {
+func setQuietInstall(devInfo setupapi.DevInfo, devInfoData *setupapi.DevInfoData) error {
-	devInstallParams, err := deviceInfoSet.DeviceInstallParams(deviceInfoData)
+	devInstallParams, err := devInfo.DeviceInstallParams(devInfoData)
 	if err != nil {
 		return err
 	}
 
 	devInstallParams.Flags |= setupapi.DI_QUIETINSTALL
-	return deviceInfoSet.SetDeviceInstallParams(deviceInfoData, devInstallParams)
+	return devInfo.SetDeviceInstallParams(devInfoData, devInstallParams)
 }
 
 // deviceTypeName returns pool-specific device type name.
@@ -721,18 +739,18 @@ func (wintun *Interface) tcpipInterfaceRegKeyName() (path string, err error) {
 	return fmt.Sprintf("SYSTEM\\CurrentControlSet\\Services\\%s", paths[0]), nil
 }
 
-// deviceData returns TUN device info list handle and interface device info
+// devInfoData returns TUN device info list handle and interface device info
 // data. The device info list handle must be closed after use. In case the
 // device is not found, windows.ERROR_OBJECT_NOT_FOUND is returned.
-func (wintun *Interface) deviceData() (setupapi.DevInfo, *setupapi.DevInfoData, error) {
+func (wintun *Interface) devInfoData() (setupapi.DevInfo, *setupapi.DevInfoData, error) {
 	// Create a list of network devices.
-	devInfoList, err := setupapi.SetupDiGetClassDevsEx(&deviceClassNetGUID, "", 0, setupapi.DIGCF_PRESENT, setupapi.DevInfo(0), "")
+	devInfo, err := setupapi.SetupDiGetClassDevsEx(&deviceClassNetGUID, "", 0, setupapi.DIGCF_PRESENT, setupapi.DevInfo(0), "")
 	if err != nil {
 		return 0, nil, fmt.Errorf("SetupDiGetClassDevsEx(%v) failed: %v", deviceClassNetGUID, err.Error())
 	}
 
 	for index := 0; ; index++ {
-		deviceData, err := devInfoList.EnumDeviceInfo(index)
+		devInfoData, err := devInfo.EnumDeviceInfo(index)
 		if err != nil {
 			if err == windows.ERROR_NO_MORE_ITEMS {
 				break
@@ -742,22 +760,22 @@ func (wintun *Interface) deviceData() (setupapi.DevInfo, *setupapi.DevInfoData,
 
 		// Get interface ID.
 		// TODO: Store some ID in the Wintun object such that this call isn't required.
-		wintun2, err := makeWintun(devInfoList, deviceData, wintun.pool)
+		wintun2, err := makeWintun(devInfo, devInfoData, wintun.pool)
 		if err != nil {
 			continue
 		}
 
 		if wintun.cfgInstanceID == wintun2.cfgInstanceID {
-			err = setQuietInstall(devInfoList, deviceData)
+			err = setQuietInstall(devInfo, devInfoData)
 			if err != nil {
-				devInfoList.Close()
+				devInfo.Close()
 				return 0, nil, fmt.Errorf("Setting quiet installation failed: %v", err)
 			}
-			return devInfoList, deviceData, nil
+			return devInfo, devInfoData, nil
 		}
 	}
 
-	devInfoList.Close()
+	devInfo.Close()
 	return 0, nil, windows.ERROR_OBJECT_NOT_FOUND
 }