all: use Go 1.19 and its atomic types

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

Author: bradfitz

conn/bind_windows.go

@@ -74,7 +74,7 @@ type afWinRingBind struct {
 type WinRingBind struct {
 	v4, v6 afWinRingBind
 	mu     sync.RWMutex
-	isOpen uint32
+	isOpen atomic.Uint32 // 0, 1, or 2
 }
 
 func NewDefaultBind() Bind { return NewWinRingBind() }
@@ -212,7 +212,7 @@ func (bind *afWinRingBind) CloseAndZero() {
 }
 
 func (bind *WinRingBind) closeAndZero() {
-	atomic.StoreUint32(&bind.isOpen, 0)
+	bind.isOpen.Store(0)
 	bind.v4.CloseAndZero()
 	bind.v6.CloseAndZero()
 }
@@ -276,7 +276,7 @@ func (bind *WinRingBind) Open(port uint16) (recvFns []ReceiveFunc, selectedPort
 			bind.closeAndZero()
 		}
 	}()
-	if atomic.LoadUint32(&bind.isOpen) != 0 {
+	if bind.isOpen.Load() != 0 {
 		return nil, 0, ErrBindAlreadyOpen
 	}
 	var sa windows.Sockaddr
@@ -299,17 +299,17 @@ func (bind *WinRingBind) Open(port uint16) (recvFns []ReceiveFunc, selectedPort
 			return nil, 0, err
 		}
 	}
-	atomic.StoreUint32(&bind.isOpen, 1)
+	bind.isOpen.Store(1)
 	return []ReceiveFunc{bind.receiveIPv4, bind.receiveIPv6}, selectedPort, err
 }
 
 func (bind *WinRingBind) Close() error {
 	bind.mu.RLock()
-	if atomic.LoadUint32(&bind.isOpen) != 1 {
+	if bind.isOpen.Load() != 1 {
 		bind.mu.RUnlock()
 		return nil
 	}
-	atomic.StoreUint32(&bind.isOpen, 2)
+	bind.isOpen.Store(2)
 	windows.PostQueuedCompletionStatus(bind.v4.rx.iocp, 0, 0, nil)
 	windows.PostQueuedCompletionStatus(bind.v4.tx.iocp, 0, 0, nil)
 	windows.PostQueuedCompletionStatus(bind.v6.rx.iocp, 0, 0, nil)
@@ -345,8 +345,8 @@ func (bind *afWinRingBind) InsertReceiveRequest() error {
 //go:linkname procyield runtime.procyield
 func procyield(cycles uint32)
 
-func (bind *afWinRingBind) Receive(buf []byte, isOpen *uint32) (int, Endpoint, error) {
-	if atomic.LoadUint32(isOpen) != 1 {
+func (bind *afWinRingBind) Receive(buf []byte, isOpen *atomic.Uint32) (int, Endpoint, error) {
+	if isOpen.Load() != 1 {
 		return 0, nil, net.ErrClosed
 	}
 	bind.rx.mu.Lock()
@@ -359,7 +359,7 @@ retry:
 	count = 0
 	for tries := 0; count == 0 && tries < receiveSpins; tries++ {
 		if tries > 0 {
-			if atomic.LoadUint32(isOpen) != 1 {
+			if isOpen.Load() != 1 {
 				return 0, nil, net.ErrClosed
 			}
 			procyield(1)
@@ -378,7 +378,7 @@ retry:
 		if err != nil {
 			return 0, nil, err
 		}
-		if atomic.LoadUint32(isOpen) != 1 {
+		if isOpen.Load() != 1 {
 			return 0, nil, net.ErrClosed
 		}
 		count = winrio.DequeueCompletion(bind.rx.cq, results[:])
@@ -395,7 +395,7 @@ retry:
 	// huge packets. Just try again when this happens. The infinite loop this could cause is still limited to
 	// attacker bandwidth, just like the rest of the receive path.
 	if windows.Errno(results[0].Status) == windows.WSAEMSGSIZE {
-		if atomic.LoadUint32(isOpen) != 1 {
+		if isOpen.Load() != 1 {
 			return 0, nil, net.ErrClosed
 		}
 		goto retry
@@ -421,8 +421,8 @@ func (bind *WinRingBind) receiveIPv6(buf []byte) (int, Endpoint, error) {
 	return bind.v6.Receive(buf, &bind.isOpen)
 }
 
-func (bind *afWinRingBind) Send(buf []byte, nend *WinRingEndpoint, isOpen *uint32) error {
-	if atomic.LoadUint32(isOpen) != 1 {
+func (bind *afWinRingBind) Send(buf []byte, nend *WinRingEndpoint, isOpen *atomic.Uint32) error {
+	if isOpen.Load() != 1 {
 		return net.ErrClosed
 	}
 	if len(buf) > bytesPerPacket {
@@ -444,7 +444,7 @@ func (bind *afWinRingBind) Send(buf []byte, nend *WinRingEndpoint, isOpen *uint3
 		if err != nil {
 			return err
 		}
-		if atomic.LoadUint32(isOpen) != 1 {
+		if isOpen.Load() != 1 {
 			return net.ErrClosed
 		}
 		count = winrio.DequeueCompletion(bind.tx.cq, results[:])
@@ -538,7 +538,7 @@ func (bind *StdNetBind) BindSocketToInterface6(interfaceIndex uint32, blackhole
 func (bind *WinRingBind) BindSocketToInterface4(interfaceIndex uint32, blackhole bool) error {
 	bind.mu.RLock()
 	defer bind.mu.RUnlock()
-	if atomic.LoadUint32(&bind.isOpen) != 1 {
+	if bind.isOpen.Load() != 1 {
 		return net.ErrClosed
 	}
 	err := bindSocketToInterface4(bind.v4.sock, interfaceIndex)
@@ -552,7 +552,7 @@ func (bind *WinRingBind) BindSocketToInterface4(interfaceIndex uint32, blackhole
 func (bind *WinRingBind) BindSocketToInterface6(interfaceIndex uint32, blackhole bool) error {
 	bind.mu.RLock()
 	defer bind.mu.RUnlock()
-	if atomic.LoadUint32(&bind.isOpen) != 1 {
+	if bind.isOpen.Load() != 1 {
 		return net.ErrClosed
 	}
 	err := bindSocketToInterface6(bind.v6.sock, interfaceIndex)

device/alignment_test.go

@@ -30,7 +30,7 @@ type Device struct {
 		// will become the actual state; Up can fail.
 		// The device can also change state multiple times between time of check and time of use.
 		// Unsynchronized uses of state must therefore be advisory/best-effort only.
-		state uint32 // actually a deviceState, but typed uint32 for convenience
+		state atomic.Uint32 // actually a deviceState, but typed uint32 for convenience
 		// stopping blocks until all inputs to Device have been closed.
 		stopping sync.WaitGroup
 		// mu protects state changes.
@@ -58,9 +58,8 @@ type Device struct {
 		keyMap       map[NoisePublicKey]*Peer
 	}
 
-	// Keep this 8-byte aligned
 	rate struct {
-		underLoadUntil int64
+		underLoadUntil atomic.Int64
 		limiter        ratelimiter.Ratelimiter
 	}
 
@@ -82,7 +81,7 @@ type Device struct {
 
 	tun struct {
 		device tun.Device
-		mtu    int32
+		mtu    atomic.Int32
 	}
 
 	ipcMutex sync.RWMutex
@@ -94,10 +93,9 @@ type Device struct {
 // There are three states: down, up, closed.
 // Transitions:
 //
-//   down -----+
-//     ↑↓      ↓
-//     up -> closed
-//
+//	down -----+
+//	  ↑↓      ↓
+//	  up -> closed
 type deviceState uint32
 
 //go:generate go run golang.org/x/tools/cmd/stringer -type deviceState -trimprefix=deviceState
@@ -110,7 +108,7 @@ const (
 // deviceState returns device.state.state as a deviceState
 // See those docs for how to interpret this value.
 func (device *Device) deviceState() deviceState {
-	return deviceState(atomic.LoadUint32(&device.state.state))
+	return deviceState(device.state.state.Load())
 }
 
 // isClosed reports whether the device is closed (or is closing).
@@ -149,14 +147,14 @@ func (device *Device) changeState(want deviceState) (err error) {
 	case old:
 		return nil
 	case deviceStateUp:
-		atomic.StoreUint32(&device.state.state, uint32(deviceStateUp))
+		device.state.state.Store(uint32(deviceStateUp))
 		err = device.upLocked()
 		if err == nil {
 			break
 		}
 		fallthrough // up failed; bring the device all the way back down
 	case deviceStateDown:
-		atomic.StoreUint32(&device.state.state, uint32(deviceStateDown))
+		device.state.state.Store(uint32(deviceStateDown))
 		errDown := device.downLocked()
 		if err == nil {
 			err = errDown
@@ -182,7 +180,7 @@ func (device *Device) upLocked() error {
 	device.peers.RLock()
 	for _, peer := range device.peers.keyMap {
 		peer.Start()
-		if atomic.LoadUint32(&peer.persistentKeepaliveInterval) > 0 {
+		if peer.persistentKeepaliveInterval.Load() > 0 {
 			peer.SendKeepalive()
 		}
 	}
@@ -219,11 +217,11 @@ func (device *Device) IsUnderLoad() bool {
 	now := time.Now()
 	underLoad := len(device.queue.handshake.c) >= QueueHandshakeSize/8
 	if underLoad {
-		atomic.StoreInt64(&device.rate.underLoadUntil, now.Add(UnderLoadAfterTime).UnixNano())
+		device.rate.underLoadUntil.Store(now.Add(UnderLoadAfterTime).UnixNano())
 		return true
 	}
 	// check if recently under load
-	return atomic.LoadInt64(&device.rate.underLoadUntil) > now.UnixNano()
+	return device.rate.underLoadUntil.Load() > now.UnixNano()
 }
 
 func (device *Device) SetPrivateKey(sk NoisePrivateKey) error {
@@ -283,7 +281,7 @@ func (device *Device) SetPrivateKey(sk NoisePrivateKey) error {
 
 func NewDevice(tunDevice tun.Device, bind conn.Bind, logger *Logger) *Device {
 	device := new(Device)
-	device.state.state = uint32(deviceStateDown)
+	device.state.state.Store(uint32(deviceStateDown))
 	device.closed = make(chan struct{})
 	device.log = logger
 	device.net.bind = bind
@@ -293,7 +291,7 @@ func NewDevice(tunDevice tun.Device, bind conn.Bind, logger *Logger) *Device {
 		device.log.Errorf("Trouble determining MTU, assuming default: %v", err)
 		mtu = DefaultMTU
 	}
-	device.tun.mtu = int32(mtu)
+	device.tun.mtu.Store(int32(mtu))
 	device.peers.keyMap = make(map[NoisePublicKey]*Peer)
 	device.rate.limiter.Init()
 	device.indexTable.Init()
@@ -359,7 +357,7 @@ func (device *Device) Close() {
 	if device.isClosed() {
 		return
 	}
-	atomic.StoreUint32(&device.state.state, uint32(deviceStateClosed))
+	device.state.state.Store(uint32(deviceStateClosed))
 	device.log.Verbosef("Device closing")
 
 	device.tun.device.Close()

device/device.go

@@ -333,7 +333,7 @@ func BenchmarkThroughput(b *testing.B) {
 
 	// Measure how long it takes to receive b.N packets,
 	// starting when we receive the first packet.
-	var recv uint64
+	var recv atomic.Uint64
 	var elapsed time.Duration
 	var wg sync.WaitGroup
 	wg.Add(1)
@@ -342,7 +342,7 @@ func BenchmarkThroughput(b *testing.B) {
 		var start time.Time
 		for {
 			<-pair[0].tun.Inbound
-			new := atomic.AddUint64(&recv, 1)
+			new := recv.Add(1)
 			if new == 1 {
 				start = time.Now()
 			}
@@ -358,7 +358,7 @@ func BenchmarkThroughput(b *testing.B) {
 	ping := tuntest.Ping(pair[0].ip, pair[1].ip)
 	pingc := pair[1].tun.Outbound
 	var sent uint64
-	for atomic.LoadUint64(&recv) != uint64(b.N) {
+	for recv.Load() != uint64(b.N) {
 		sent++
 		pingc <- ping
 	}

device/device_test.go

@@ -10,7 +10,6 @@ import (
 	"sync"
 	"sync/atomic"
 	"time"
-	"unsafe"
 
 	"golang.zx2c4.com/wireguard/replay"
 )
@@ -23,7 +22,7 @@ import (
  */
 
 type Keypair struct {
-	sendNonce    uint64 // accessed atomically
+	sendNonce    atomic.Uint64
 	send         cipher.AEAD
 	receive      cipher.AEAD
 	replayFilter replay.Filter
@@ -37,15 +36,7 @@ type Keypairs struct {
 	sync.RWMutex
 	current  *Keypair
 	previous *Keypair
-	next     *Keypair
-}
-
-func (kp *Keypairs) storeNext(next *Keypair) {
-	atomic.StorePointer((*unsafe.Pointer)((unsafe.Pointer)(&kp.next)), (unsafe.Pointer)(next))
-}
-
-func (kp *Keypairs) loadNext() *Keypair {
-	return (*Keypair)(atomic.LoadPointer((*unsafe.Pointer)((unsafe.Pointer)(&kp.next))))
+	next     atomic.Pointer[Keypair]
 }
 
 func (kp *Keypairs) Current() *Keypair {