Rewrite timers and related state machines

constants.go

@@ -17,6 +17,8 @@ const (
 	RekeyAfterTime          = time.Second * 120
 	RekeyAttemptTime        = time.Second * 90
 	RekeyTimeout            = time.Second * 5
+	MaxTimerHandshakes      = 90 / 5 /* RekeyAttemptTime / RekeyTimeout */
+	RekeyTimeoutJitterMaxMs = 334
 	RejectAfterTime         = time.Second * 180
 	KeepaliveTimeout        = time.Second * 10
 	CookieRefreshTime       = time.Second * 120
@@ -24,11 +26,6 @@ const (
 	PaddingMultiple         = 16
 )
 
-const (
-	RekeyAfterTimeReceiving = RejectAfterTime - KeepaliveTimeout - RekeyTimeout
-	NewHandshakeTime        = KeepaliveTimeout + RekeyTimeout // upon failure to acknowledge transport message
-)
-
 /* Implementation specific constants */
 
 const (

device.go

@@ -74,8 +74,8 @@ type Device struct {
 		handshake  chan QueueHandshakeElement
 	}
 
-	signal struct {
+	signals struct {
-		stop Signal
+		stop chan struct{}
 	}
 
 	tun struct {
@@ -302,7 +302,7 @@ func NewDevice(tun TUNDevice, logger *Logger) *Device {
 
 	// prepare signals
 
-	device.signal.stop = NewSignal()
+	device.signals.stop = make(chan struct{}, 1)
 
 	// prepare net
 
@@ -400,7 +400,7 @@ func (device *Device) Close() {
 
 	device.isUp.Set(false)
 
-	device.signal.stop.Broadcast()
+	close(device.signals.stop)
 
 	device.state.stopping.Wait()
 	device.FlushPacketQueues()
@@ -413,5 +413,5 @@ func (device *Device) Close() {
 }
 
 func (device *Device) Wait() chan struct{} {
-	return device.signal.stop.Wait()
+	return device.signals.stop
 }

event.go

@@ -1,43 +0,0 @@
-package main
-
-import (
-	"sync/atomic"
-	"time"
-)
-
-type Event struct {
-	guard    int32
-	next     time.Time
-	interval time.Duration
-	C        chan struct{}
-}
-
-func newEvent(interval time.Duration) *Event {
-	return &Event{
-		guard:    0,
-		next:     time.Now(),
-		interval: interval,
-		C:        make(chan struct{}, 1),
-	}
-}
-
-func (e *Event) Clear() {
-	select {
-	case <-e.C:
-	default:
-	}
-}
-
-func (e *Event) Fire() {
-	if e == nil || atomic.SwapInt32(&e.guard, 1) != 0 {
-		return
-	}
-	if now := time.Now(); now.After(e.next) {
-		select {
-		case e.C <- struct{}{}:
-		default:
-		}
-		e.next = now.Add(e.interval)
-	}
-	atomic.StoreInt32(&e.guard, 0)
-}

index.go

@@ -18,7 +18,7 @@ import (
 type IndexTableEntry struct {
 	peer      *Peer
 	handshake *Handshake
-	keyPair   *KeyPair
+	keyPair   *Keypair
 }
 
 type IndexTable struct {

keypair.go

@@ -18,7 +18,7 @@ import (
  * we plan to resolve this issue; whenever Go allows us to do so.
  */
 
-type KeyPair struct {
+type Keypair struct {
 	sendNonce    uint64
 	send         cipher.AEAD
 	receive      cipher.AEAD
@@ -29,20 +29,20 @@ type KeyPair struct {
 	remoteIndex  uint32
 }
 
-type KeyPairs struct {
+type Keypairs struct {
 	mutex    sync.RWMutex
-	current  *KeyPair
+	current  *Keypair
-	previous *KeyPair
+	previous *Keypair
-	next     *KeyPair // not yet "confirmed by transport"
+	next     *Keypair // not yet "confirmed by transport"
 }
 
-func (kp *KeyPairs) Current() *KeyPair {
+func (kp *Keypairs) Current() *Keypair {
 	kp.mutex.RLock()
 	defer kp.mutex.RUnlock()
 	return kp.current
 }
 
-func (device *Device) DeleteKeyPair(key *KeyPair) {
+func (device *Device) DeleteKeypair(key *Keypair) {
 	if key != nil {
 		device.indices.Delete(key.localIndex)
 	}

main.go

@@ -30,6 +30,8 @@ func printUsage() {
 }
 
 func warning() {
+	shouldQuit := false
+
 	fmt.Fprintln(os.Stderr, "WARNING WARNING WARNING WARNING WARNING WARNING WARNING")
 	fmt.Fprintln(os.Stderr, "W                                                     G")
 	fmt.Fprintln(os.Stderr, "W   This is alpha software. It will very likely not   G")
@@ -37,6 +39,8 @@ func warning() {
 	fmt.Fprintln(os.Stderr, "W   horribly wrong. You have been warned. Proceed     G")
 	fmt.Fprintln(os.Stderr, "W   at your own risk.                                 G")
 	if runtime.GOOS == "linux" {
+		shouldQuit = os.Getenv("WG_I_PREFER_BUGGY_USERSPACE_TO_POLISHED_KMOD") != "1"
+
 		fmt.Fprintln(os.Stderr, "W                                                     G")
 		fmt.Fprintln(os.Stderr, "W   Furthermore, you are running this software on a   G")
 		fmt.Fprintln(os.Stderr, "W   Linux kernel, which is probably unnecessary and   G")
@@ -46,9 +50,20 @@ func warning() {
 		fmt.Fprintln(os.Stderr, "W   program. For more information on installing the   G")
 		fmt.Fprintln(os.Stderr, "W   kernel module, please visit:                      G")
 		fmt.Fprintln(os.Stderr, "W           https://www.wireguard.com/install         G")
+		if shouldQuit {
+			fmt.Fprintln(os.Stderr, "W                                                     G")
+			fmt.Fprintln(os.Stderr, "W   If you still want to use this program, against    G")
+			fmt.Fprintln(os.Stderr, "W   the sage advice here, please first export this    G")
+			fmt.Fprintln(os.Stderr, "W   environment variable:                             G")
+			fmt.Fprintln(os.Stderr, "W   WG_I_PREFER_BUGGY_USERSPACE_TO_POLISHED_KMOD=1    G")
+		}
 	}
 	fmt.Fprintln(os.Stderr, "W                                                     G")
 	fmt.Fprintln(os.Stderr, "WARNING WARNING WARNING WARNING WARNING WARNING WARNING")
+
+	if shouldQuit {
+		os.Exit(1)
+	}
 }
 
 func main() {

noise-protocol.go

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: GPL-2.0
  *
- * Copyright (C) 2017-2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ * Copyright (C) 2015-2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
  */
 
 package main
@@ -488,7 +488,7 @@ func (device *Device) ConsumeMessageResponse(msg *MessageResponse) *Peer {
 /* Derives a new key-pair from the current handshake state
  *
  */
-func (peer *Peer) NewKeyPair() *KeyPair {
+func (peer *Peer) NewKeypair() *Keypair {
 	device := peer.device
 	handshake := &peer.handshake
 	handshake.mutex.Lock()
@@ -528,7 +528,7 @@ func (peer *Peer) NewKeyPair() *KeyPair {
 
 	// create AEAD instances
 
-	keyPair := new(KeyPair)
+	keyPair := new(Keypair)
 	keyPair.send, _ = chacha20poly1305.New(sendKey[:])
 	keyPair.receive, _ = chacha20poly1305.New(recvKey[:])
 
@@ -559,24 +559,27 @@ func (peer *Peer) NewKeyPair() *KeyPair {
 	kp := &peer.keyPairs
 	kp.mutex.Lock()
 
+	peer.timersSessionDerived()
+
+	previous := kp.previous
+	next := kp.next
+	current := kp.current
+
 	if isInitiator {
-		if kp.previous != nil {
+		if next != nil {
-			device.DeleteKeyPair(kp.previous)
+			kp.next = nil
-			kp.previous = nil
+			kp.previous = next
-		}
+			device.DeleteKeypair(current)
-
-		if kp.next != nil {
-			kp.previous = kp.next
-			kp.next = keyPair
 		} else {
-			kp.previous = kp.current
+			kp.previous = current
+		}
+		device.DeleteKeypair(previous)
 		kp.current = keyPair
-			peer.event.newKeyPair.Fire()
-		}
-
 	} else {
 		kp.next = keyPair
+		device.DeleteKeypair(next)
 		kp.previous = nil
+		device.DeleteKeypair(previous)
 	}
 	kp.mutex.Unlock()
 

noise_test.go

@@ -102,8 +102,8 @@ func TestNoiseHandshake(t *testing.T) {
 
 	t.Log("deriving keys")
 
-	key1 := peer1.NewKeyPair()
+	key1 := peer1.NewKeypair()
-	key2 := peer2.NewKeyPair()
+	key2 := peer2.NewKeypair()
 
 	if key1 == nil {
 		t.Fatal("failed to dervice key-pair for peer 1")

peer.go

@@ -14,14 +14,13 @@ import (
 )
 
 const (
-	PeerRoutineNumber = 4
+	PeerRoutineNumber = 3
-	EventInterval     = 10 * time.Millisecond
 )
 
 type Peer struct {
 	isRunning                   AtomicBool
 	mutex                       sync.RWMutex
-	keyPairs                    KeyPairs
+	keyPairs                    Keypairs
 	handshake                   Handshake
 	device                      *Device
 	endpoint                    Endpoint
@@ -34,34 +33,28 @@ type Peer struct {
 		lastHandshakeNano int64  // nano seconds since epoch
 	}
 
-	time struct {
+	timers struct {
-		mutex         sync.RWMutex
+		retransmitHandshake     *Timer
-		lastSend      time.Time // last send message
+		sendKeepalive           *Timer
-		lastHandshake time.Time // last completed handshake
+		newHandshake            *Timer
-		nextKeepalive time.Time
+		zeroKeyMaterial         *Timer
+		persistentKeepalive     *Timer
+		handshakeAttempts       uint
+		needAnotherKeepalive    bool
+		sentLastMinuteHandshake bool
+		lastSentHandshake       time.Time
 	}
 
-	event struct {
+	signals struct {
-		dataSent                        *Event
+		newKeypairArrived chan struct{}
-		dataReceived                    *Event
+		flushNonceQueue   chan struct{}
-		anyAuthenticatedPacketReceived  *Event
-		anyAuthenticatedPacketTraversal *Event
-		handshakeCompleted              *Event
-		handshakePushDeadline           *Event
-		handshakeBegin                  *Event
-		ephemeralKeyCreated             *Event
-		newKeyPair                      *Event
-		flushNonceQueue                 *Event
-	}
-
-	timer struct {
-		sendLastMinuteHandshake AtomicBool
 	}
 
 	queue struct {
 		nonce                           chan *QueueOutboundElement // nonce / pre-handshake queue
 		outbound                        chan *QueueOutboundElement // sequential ordering of work
 		inbound                         chan *QueueInboundElement  // sequential ordering of work
+		packetInNonceQueueIsAwaitingKey bool
 	}
 
 	routines struct {
@@ -188,6 +181,8 @@ func (peer *Peer) Start() {
 	peer.routines.starting.Wait()
 	peer.routines.stopping.Wait()
 	peer.routines.stop = make(chan struct{})
+	peer.routines.starting.Add(PeerRoutineNumber)
+	peer.routines.stopping.Add(PeerRoutineNumber)
 
 	// prepare queues
 
@@ -195,28 +190,13 @@ func (peer *Peer) Start() {
 	peer.queue.outbound = make(chan *QueueOutboundElement, QueueOutboundSize)
 	peer.queue.inbound = make(chan *QueueInboundElement, QueueInboundSize)
 
-	// events
+	peer.timersInit()
-
+	peer.signals.newKeypairArrived = make(chan struct{}, 1)
-	peer.event.dataSent = newEvent(EventInterval)
+	peer.signals.flushNonceQueue = make(chan struct{}, 1)
-	peer.event.dataReceived = newEvent(EventInterval)
-	peer.event.anyAuthenticatedPacketReceived = newEvent(EventInterval)
-	peer.event.anyAuthenticatedPacketTraversal = newEvent(EventInterval)
-	peer.event.handshakeCompleted = newEvent(EventInterval)
-	peer.event.handshakePushDeadline = newEvent(EventInterval)
-	peer.event.handshakeBegin = newEvent(EventInterval)
-	peer.event.ephemeralKeyCreated = newEvent(EventInterval)
-	peer.event.newKeyPair = newEvent(EventInterval)
-	peer.event.flushNonceQueue = newEvent(EventInterval)
-
-	peer.isRunning.Set(true)
 
 	// wait for routines to start
 
-	peer.routines.starting.Add(PeerRoutineNumber)
-	peer.routines.stopping.Add(PeerRoutineNumber)
-
 	go peer.RoutineNonce()
-	go peer.RoutineTimerHandler()
 	go peer.RoutineSequentialSender()
 	go peer.RoutineSequentialReceiver()
 
@@ -238,6 +218,8 @@ func (peer *Peer) Stop() {
 	device := peer.device
 	device.log.Debug.Println(peer, ": Stopping...")
 
+	peer.timersStop()
+
 	// stop & wait for ongoing peer routines
 
 	peer.routines.starting.Wait()
@@ -255,9 +237,9 @@ func (peer *Peer) Stop() {
 	kp := &peer.keyPairs
 	kp.mutex.Lock()
 
-	device.DeleteKeyPair(kp.previous)
+	device.DeleteKeypair(kp.previous)
-	device.DeleteKeyPair(kp.current)
+	device.DeleteKeypair(kp.current)
-	device.DeleteKeyPair(kp.next)
+	device.DeleteKeypair(kp.next)
 
 	kp.previous = nil
 	kp.current = nil
@@ -271,4 +253,6 @@ func (peer *Peer) Stop() {
 	device.indices.Delete(hs.localIndex)
 	hs.Clear()
 	hs.mutex.Unlock()
+
+	peer.FlushNonceQueue()
 }

receive.go

@@ -31,7 +31,7 @@ type QueueInboundElement struct {
 	buffer   *[MaxMessageSize]byte
 	packet   []byte
 	counter  uint64
-	keyPair  *KeyPair
+	keyPair  *Keypair
 	endpoint Endpoint
 }
 
@@ -99,6 +99,21 @@ func (device *Device) addToHandshakeQueue(
 	}
 }
 
+/* Called when a new authenticated message has been received
+ *
+ * NOTE: Not thread safe, but called by sequential receiver!
+ */
+func (peer *Peer) keepKeyFreshReceiving() {
+	if peer.timers.sentLastMinuteHandshake {
+		return
+	}
+	kp := peer.keyPairs.Current()
+	if kp != nil && kp.isInitiator && time.Now().Sub(kp.created) > (RejectAfterTime-KeepaliveTimeout-RekeyTimeout) {
+		peer.timers.sentLastMinuteHandshake = true
+		peer.SendHandshakeInitiation(false)
+	}
+}
+
 /* Receives incoming datagrams for the device
  *
  * Every time the bind is updated a new routine is started for
@@ -245,7 +260,7 @@ func (device *Device) RoutineDecryption() {
 
 	for {
 		select {
-		case <-device.signal.stop.Wait():
+		case <-device.signals.stop:
 			return
 
 		case elem, ok := <-device.queue.decryption:
@@ -317,7 +332,7 @@ func (device *Device) RoutineHandshake() {
 	for {
 		select {
 		case elem, ok = <-device.queue.handshake:
-		case <-device.signal.stop.Wait():
+		case <-device.signals.stop:
 			return
 		}
 
@@ -441,8 +456,8 @@ func (device *Device) RoutineHandshake() {
 
 			// update timers
 
-			peer.event.anyAuthenticatedPacketTraversal.Fire()
+			peer.timersAnyAuthenticatedPacketTraversal()
-			peer.event.anyAuthenticatedPacketReceived.Fire()
+			peer.timersAnyAuthenticatedPacketReceived()
 
 			// update endpoint
 
@@ -460,10 +475,11 @@ func (device *Device) RoutineHandshake() {
 				continue
 			}
 
-			peer.TimerEphemeralKeyCreated()
+			if peer.NewKeypair() == nil {
-			peer.NewKeyPair()
+				continue
+			}
 
-			logDebug.Println(peer, ": Creating handshake response")
+			logDebug.Println(peer, ": Sending handshake response")
 
 			writer := bytes.NewBuffer(temp[:0])
 			binary.Write(writer, binary.LittleEndian, response)
@@ -472,9 +488,10 @@ func (device *Device) RoutineHandshake() {
 
 			// send response
 
+			peer.timers.lastSentHandshake = time.Now()
 			err = peer.SendBuffer(packet)
 			if err == nil {
-				peer.event.anyAuthenticatedPacketTraversal.Fire()
+				peer.timersAnyAuthenticatedPacketTraversal()
 			} else {
 				logError.Println(peer, ": Failed to send handshake response", err)
 			}
@@ -510,18 +527,23 @@ func (device *Device) RoutineHandshake() {
 
 			logDebug.Println(peer, ": Received handshake response")
 
-			peer.TimerEphemeralKeyCreated()
-
 			// update timers
 
-			peer.event.anyAuthenticatedPacketTraversal.Fire()
+			peer.timersAnyAuthenticatedPacketTraversal()
-			peer.event.anyAuthenticatedPacketReceived.Fire()
+			peer.timersAnyAuthenticatedPacketReceived()
-			peer.event.handshakeCompleted.Fire()
 
 			// derive key-pair
 
-			peer.NewKeyPair()
+			if peer.NewKeypair() == nil {
-			peer.SendKeepAlive()
+				continue
+			}
+
+			peer.timersHandshakeComplete()
+			peer.SendKeepalive()
+			select {
+			case peer.signals.newKeypairArrived <- struct{}{}:
+			default:
+			}
 		}
 	}
 }
@@ -569,38 +591,41 @@ func (peer *Peer) RoutineSequentialReceiver() {
 				continue
 			}
 
-			peer.event.anyAuthenticatedPacketTraversal.Fire()
-			peer.event.anyAuthenticatedPacketReceived.Fire()
-			peer.KeepKeyFreshReceiving()
-
-			// check if using new key-pair
-
-			kp := &peer.keyPairs
-			kp.mutex.Lock()
-			if kp.next == elem.keyPair {
-				peer.event.handshakeCompleted.Fire()
-				if kp.previous != nil {
-					device.DeleteKeyPair(kp.previous)
-				}
-				kp.previous = kp.current
-				kp.current = kp.next
-				kp.next = nil
-			}
-			kp.mutex.Unlock()
-
 			// update endpoint
 
 			peer.mutex.Lock()
 			peer.endpoint = elem.endpoint
 			peer.mutex.Unlock()
 
-			// check for keep-alive
+			// check if using new key-pair
+
+			kp := &peer.keyPairs
+			kp.mutex.Lock() //TODO: make this into an RW lock to reduce contention here for the equality check which is rarely true
+			if kp.next == elem.keyPair {
+				old := kp.previous
+				kp.previous = kp.current
+				device.DeleteKeypair(old)
+				kp.current = kp.next
+				kp.next = nil
+				peer.timersHandshakeComplete()
+				select {
+				case peer.signals.newKeypairArrived <- struct{}{}:
+				default:
+				}
+			}
+			kp.mutex.Unlock()
+
+			peer.keepKeyFreshReceiving()
+			peer.timersAnyAuthenticatedPacketTraversal()
+			peer.timersAnyAuthenticatedPacketReceived()
+
+			// check for keepalive
 
 			if len(elem.packet) == 0 {
-				logDebug.Println(peer, ": Received keep-alive")
+				logDebug.Println(peer, ": Receiving keepalive packet")
 				continue
 			}
-			peer.event.dataReceived.Fire()
+			peer.timersDataReceived()
 
 			// verify source and strip padding
 

send.go

@@ -6,6 +6,7 @@
 package main
 
 import (
+	"bytes"
 	"encoding/binary"
 	"golang.org/x/crypto/chacha20poly1305"
 	"golang.org/x/net/ipv4"
@@ -46,21 +47,10 @@ type QueueOutboundElement struct {
 	buffer  *[MaxMessageSize]byte // slice holding the packet data
 	packet  []byte                // slice of "buffer" (always!)
 	nonce   uint64                // nonce for encryption
-	keyPair *KeyPair              // key-pair for encryption
+	keyPair *Keypair              // key-pair for encryption
 	peer    *Peer                 // related peer
 }
 
-func (peer *Peer) flushNonceQueue() {
-	elems := len(peer.queue.nonce)
-	for i := 0; i < elems; i++ {
-		select {
-		case <-peer.queue.nonce:
-		default:
-			return
-		}
-	}
-}
-
 func (device *Device) NewOutboundElement() *QueueOutboundElement {
 	return &QueueOutboundElement{
 		dropped: AtomicFalse,
@@ -114,6 +104,73 @@ func addToEncryptionQueue(
 	}
 }
 
+/* Queues a keepalive if no packets are queued for peer
+ */
+func (peer *Peer) SendKeepalive() bool {
+	if len(peer.queue.nonce) != 0 || peer.queue.packetInNonceQueueIsAwaitingKey {
+		return false
+	}
+	elem := peer.device.NewOutboundElement()
+	elem.packet = nil
+	select {
+	case peer.queue.nonce <- elem:
+		peer.device.log.Debug.Println(peer, ": Sending keepalive packet")
+		return true
+	default:
+		return false
+	}
+}
+
+/* Sends a new handshake initiation message to the peer (endpoint)
+ */
+func (peer *Peer) SendHandshakeInitiation(isRetry bool) error {
+	if !isRetry {
+		peer.timers.handshakeAttempts = 0
+	}
+
+	if time.Now().Sub(peer.timers.lastSentHandshake) < RekeyTimeout {
+		return nil
+	}
+	peer.timers.lastSentHandshake = time.Now() //TODO: locking for this variable?
+
+	// create initiation message
+
+	msg, err := peer.device.CreateMessageInitiation(peer)
+	if err != nil {
+		return err
+	}
+
+	peer.device.log.Debug.Println(peer, ": Sending handshake initiation")
+
+	// marshal handshake message
+
+	var buff [MessageInitiationSize]byte
+	writer := bytes.NewBuffer(buff[:0])
+	binary.Write(writer, binary.LittleEndian, msg)
+	packet := writer.Bytes()
+	peer.mac.AddMacs(packet)
+
+	// send to endpoint
+
+	peer.timersAnyAuthenticatedPacketTraversal()
+	peer.timersHandshakeInitiated()
+	return peer.SendBuffer(packet)
+}
+
+/* Called when a new authenticated message has been send
+ *
+ */
+func (peer *Peer) keepKeyFreshSending() {
+	kp := peer.keyPairs.Current()
+	if kp == nil {
+		return
+	}
+	nonce := atomic.LoadUint64(&kp.sendNonce)
+	if nonce > RekeyAfterMessages || (kp.isInitiator && time.Now().Sub(kp.created) > RekeyAfterTime) {
+		peer.SendHandshakeInitiation(false)
+	}
+}
+
 /* Reads packets from the TUN and inserts
  * into nonce queue for peer
  *
@@ -180,13 +237,22 @@ func (device *Device) RoutineReadFromTUN() {
 		// insert into nonce/pre-handshake queue
 
 		if peer.isRunning.Get() {
-			peer.event.handshakePushDeadline.Fire()
+			if peer.queue.packetInNonceQueueIsAwaitingKey {
+				peer.SendHandshakeInitiation(false)
+			}
 			addToOutboundQueue(peer.queue.nonce, elem)
 			elem = device.NewOutboundElement()
 		}
 	}
 }
 
+func (peer *Peer) FlushNonceQueue() {
+	select {
+	case peer.signals.flushNonceQueue <- struct{}{}:
+	default:
+	}
+}
+
 /* Queues packets when there is no handshake.
  * Then assigns nonces to packets sequentially
  * and creates "work" structs for workers
@@ -194,13 +260,14 @@ func (device *Device) RoutineReadFromTUN() {
  * Obs. A single instance per peer
  */
 func (peer *Peer) RoutineNonce() {
-	var keyPair *KeyPair
+	var keyPair *Keypair
 
 	device := peer.device
 	logDebug := device.log.Debug
 
 	defer func() {
 		logDebug.Println(peer, ": Routine: nonce worker - stopped")
+		peer.queue.packetInNonceQueueIsAwaitingKey = false
 		peer.routines.stopping.Done()
 	}()
 
@@ -209,8 +276,7 @@ func (peer *Peer) RoutineNonce() {
 
 	for {
 	NextPacket:
-
+		peer.queue.packetInNonceQueueIsAwaitingKey = false
-		peer.event.flushNonceQueue.Clear()
 
 		select {
 		case <-peer.routines.stop:
@@ -225,34 +291,48 @@ func (peer *Peer) RoutineNonce() {
 			// wait for key pair
 
 			for {
-
-				peer.event.newKeyPair.Clear()
-
 				keyPair = peer.keyPairs.Current()
 				if keyPair != nil && keyPair.sendNonce < RejectAfterMessages {
 					if time.Now().Sub(keyPair.created) < RejectAfterTime {
 						break
 					}
 				}
+				peer.queue.packetInNonceQueueIsAwaitingKey = true
 
-				peer.event.handshakeBegin.Fire()
+				select {
+				case <-peer.signals.newKeypairArrived:
+				default:
+				}
+
+				peer.SendHandshakeInitiation(false)
 
 				logDebug.Println(peer, ": Awaiting key-pair")
 
 				select {
-				case <-peer.event.newKeyPair.C:
+				case <-peer.signals.newKeypairArrived:
 					logDebug.Println(peer, ": Obtained awaited key-pair")
-				case <-peer.event.flushNonceQueue.C:
+				case <-peer.signals.flushNonceQueue:
+					for {
+						select {
+						case <-peer.queue.nonce:
+						default:
 							goto NextPacket
+						}
+					}
 				case <-peer.routines.stop:
 					return
 				}
 			}
+			peer.queue.packetInNonceQueueIsAwaitingKey = false
 
 			// populate work element
 
 			elem.peer = peer
 			elem.nonce = atomic.AddUint64(&keyPair.sendNonce, 1) - 1
+			// double check in case of race condition added by future code
+			if elem.nonce >= RejectAfterMessages {
+				goto NextPacket
+			}
 			elem.keyPair = keyPair
 			elem.dropped = AtomicFalse
 			elem.mutex.Lock()
@@ -288,7 +368,7 @@ func (device *Device) RoutineEncryption() {
 		// fetch next element
 
 		select {
-		case <-device.signal.stop.Wait():
+		case <-device.signals.stop:
 			return
 
 		case elem, ok := <-device.queue.encryption:
@@ -389,11 +469,11 @@ func (peer *Peer) RoutineSequentialSender() {
 
 			// update timers
 
-			peer.event.anyAuthenticatedPacketTraversal.Fire()
+			peer.timersAnyAuthenticatedPacketTraversal()
 			if len(elem.packet) != MessageKeepaliveSize {
-				peer.event.dataSent.Fire()
+				peer.timersDataSent()
 			}
-			peer.KeepKeyFreshSending()
+			peer.keepKeyFreshSending()
 		}
 	}
 }

signal.go

@@ -1,71 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0
- *
- * Copyright (C) 2017-2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
- */
-
-package main
-
-func signalSend(s chan<- struct{}) {
-	select {
-	case s <- struct{}{}:
-	default:
-	}
-}
-
-type Signal struct {
-	enabled AtomicBool
-	C       chan struct{}
-}
-
-func NewSignal() (s Signal) {
-	s.C = make(chan struct{}, 1)
-	s.Enable()
-	return
-}
-
-func (s *Signal) Close() {
-	close(s.C)
-}
-
-func (s *Signal) Disable() {
-	s.enabled.Set(false)
-	s.Clear()
-}
-
-func (s *Signal) Enable() {
-	s.enabled.Set(true)
-}
-
-/* Unblock exactly one listener
- */
-func (s *Signal) Send() {
-	if s.enabled.Get() {
-		select {
-		case s.C <- struct{}{}:
-		default:
-		}
-	}
-}
-
-/* Clear the signal if already fired
- */
-func (s Signal) Clear() {
-	select {
-	case <-s.C:
-	default:
-	}
-}
-
-/* Unblocks all listeners (forever)
- */
-func (s Signal) Broadcast() {
-	if s.enabled.Get() {
-		close(s.C)
-	}
-}
-
-/* Wait for the signal
- */
-func (s Signal) Wait() chan struct{} {
-	return s.C
-}

timers.go

@@ -1,278 +1,109 @@
 /* SPDX-License-Identifier: GPL-2.0
  *
- * Copyright (C) 2017-2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ * Copyright (C) 2015-2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ *
+ * This is based heavily on timers.c from the kernel implementation.
  */
 
 package main
 
 import (
-	"bytes"
-	"encoding/binary"
 	"math/rand"
 	"sync/atomic"
 	"time"
 )
 
-/* NOTE:
+/* This Timer structure and related functions should roughly copy the interface of
- * Notion of validity
+ * the Linux kernel's struct timer_list.
  */
 
-/* Called when a new authenticated message has been send
+type Timer struct {
- *
+	timer     *time.Timer
- */
+	isPending bool
-func (peer *Peer) KeepKeyFreshSending() {
-	kp := peer.keyPairs.Current()
-	if kp == nil {
-		return
-	}
-	nonce := atomic.LoadUint64(&kp.sendNonce)
-	if nonce > RekeyAfterMessages {
-		peer.event.handshakeBegin.Fire()
-	}
-	if kp.isInitiator && time.Now().Sub(kp.created) > RekeyAfterTime {
-		peer.event.handshakeBegin.Fire()
-	}
 }
 
-/* Called when a new authenticated message has been received
+func (peer *Peer) NewTimer(expirationFunction func(*Peer)) *Timer {
- *
+	timer := &Timer{}
- * NOTE: Not thread safe, but called by sequential receiver!
+	timer.timer = time.AfterFunc(time.Hour, func() {
- */
+		timer.isPending = false
-func (peer *Peer) KeepKeyFreshReceiving() {
+		expirationFunction(peer)
-	if peer.timer.sendLastMinuteHandshake.Get() {
+	})
-		return
+	timer.timer.Stop()
-	}
-	kp := peer.keyPairs.Current()
-	if kp == nil {
-		return
-	}
-	if !kp.isInitiator {
-		return
-	}
-	nonce := atomic.LoadUint64(&kp.sendNonce)
-	send := nonce > RekeyAfterMessages || time.Now().Sub(kp.created) > RekeyAfterTimeReceiving
-	if send {
-		// do a last minute attempt at initiating a new handshake
-		peer.timer.sendLastMinuteHandshake.Set(true)
-		peer.event.handshakeBegin.Fire()
-	}
-}
-
-/* Queues a keep-alive if no packets are queued for peer
- */
-func (peer *Peer) SendKeepAlive() bool {
-	if len(peer.queue.nonce) != 0 {
-		return false
-	}
-	elem := peer.device.NewOutboundElement()
-	elem.packet = nil
-	select {
-	case peer.queue.nonce <- elem:
-		return true
-	default:
-		return false
-	}
-}
-
-/* Called after successfully completing a handshake.
- * i.e. after:
- *
- * - Valid handshake response
- * - First transport message under the "next" key
- */
-// peer.device.log.Info.Println(peer, ": New handshake completed")
-
-/* Event:
- * An ephemeral key is generated
- *
- * i.e. after:
- *
- * CreateMessageInitiation
- * CreateMessageResponse
- *
- * Action:
- * Schedule the deletion of all key material
- * upon failure to complete a handshake
- */
-func (peer *Peer) TimerEphemeralKeyCreated() {
-	peer.event.ephemeralKeyCreated.Fire()
-	// peer.timer.zeroAllKeys.Reset(RejectAfterTime * 3)
-}
-
-/* Sends a new handshake initiation message to the peer (endpoint)
- */
-func (peer *Peer) sendNewHandshake() error {
-
-	// create initiation message
-
-	msg, err := peer.device.CreateMessageInitiation(peer)
-	if err != nil {
-		return err
-	}
-
-	// marshal handshake message
-
-	var buff [MessageInitiationSize]byte
-	writer := bytes.NewBuffer(buff[:0])
-	binary.Write(writer, binary.LittleEndian, msg)
-	packet := writer.Bytes()
-	peer.mac.AddMacs(packet)
-
-	// send to endpoint
-
-	peer.event.anyAuthenticatedPacketTraversal.Fire()
-
-	return peer.SendBuffer(packet)
-}
-
-func newTimer() *time.Timer {
-	timer := time.NewTimer(time.Hour)
-	timer.Stop()
 	return timer
 }
 
-func (peer *Peer) RoutineTimerHandler() {
+func (timer *Timer) Mod(d time.Duration) {
-
+	timer.isPending = true
-	device := peer.device
+	timer.timer.Reset(d)
-
-	logInfo := device.log.Info
-	logDebug := device.log.Debug
-
-	defer func() {
-		logDebug.Println(peer, ": Routine: timer handler - stopped")
-		peer.routines.stopping.Done()
-	}()
-
-	logDebug.Println(peer, ": Routine: timer handler - started")
-
-	// reset all timers
-
-	enableHandshake := true
-	pendingHandshakeNew := false
-	pendingKeepalivePassive := false
-	needAnotherKeepalive := false
-
-	timerKeepalivePassive := newTimer()
-	timerHandshakeDeadline := newTimer()
-	timerHandshakeTimeout := newTimer()
-	timerHandshakeNew := newTimer()
-	timerZeroAllKeys := newTimer()
-	timerKeepalivePersistent := newTimer()
-
-	interval := peer.persistentKeepaliveInterval
-	if interval > 0 {
-		duration := time.Duration(interval) * time.Second
-		timerKeepalivePersistent.Reset(duration)
 }
 
-	// signal synchronised setup complete
+func (timer *Timer) Del() {
-
+	timer.isPending = false
-	peer.routines.starting.Done()
+	timer.timer.Stop()
-
-	// handle timer events
-
-	for {
-		select {
-
-		/* stopping */
-
-		case <-peer.routines.stop:
-			return
-
-		/* events */
-
-		case <-peer.event.dataSent.C:
-			timerKeepalivePassive.Stop()
-			if !pendingHandshakeNew {
-				timerHandshakeNew.Reset(NewHandshakeTime)
 }
 
-		case <-peer.event.dataReceived.C:
+func (peer *Peer) timersActive() bool {
-			if pendingKeepalivePassive {
+	return peer.isRunning.Get() && peer.device != nil && peer.device.isUp.Get() && len(peer.device.peers.keyMap) > 0
-				needAnotherKeepalive = true
+}
+
+func expiredRetransmitHandshake(peer *Peer) {
+	if peer.timers.handshakeAttempts > MaxTimerHandshakes {
+		peer.device.log.Debug.Printf("%s: Handshake did not complete after %d attempts, giving up\n", peer, MaxTimerHandshakes+2)
+
+		if peer.timersActive() {
+			peer.timers.sendKeepalive.Del()
+		}
+
+		/* We drop all packets without a keypair and don't try again,
+		 * if we try unsuccessfully for too long to make a handshake.
+		 */
+		peer.FlushNonceQueue()
+
+		/* We set a timer for destroying any residue that might be left
+		 * of a partial exchange.
+		 */
+		if peer.timersActive() && !peer.timers.zeroKeyMaterial.isPending {
+			peer.timers.zeroKeyMaterial.Mod(RejectAfterTime * 3)
+		}
 	} else {
-				timerKeepalivePassive.Reset(KeepaliveTimeout)
+		peer.timers.handshakeAttempts++
+		peer.device.log.Debug.Printf("%s: Handshake did not complete after %d seconds, retrying (try %d)\n", peer, int(RekeyTimeout.Seconds()), peer.timers.handshakeAttempts+1)
+
+		/* We clear the endpoint address src address, in case this is the cause of trouble. */
+		peer.mutex.Lock()
+		if peer.endpoint != nil {
+			peer.endpoint.ClearSrc()
+		}
+		peer.mutex.Unlock()
+
+		peer.SendHandshakeInitiation(true)
+	}
 }
 
-		case <-peer.event.anyAuthenticatedPacketTraversal.C:
+func expiredSendKeepalive(peer *Peer) {
-			interval := peer.persistentKeepaliveInterval
+	peer.SendKeepalive()
-			if interval > 0 {
+	if peer.timers.needAnotherKeepalive {
-				duration := time.Duration(interval) * time.Second
+		peer.timers.needAnotherKeepalive = false
-				timerKeepalivePersistent.Reset(duration)
+		if peer.timersActive() {
+			peer.timers.sendKeepalive.Mod(KeepaliveTimeout)
+		}
+	}
 }
 
-		case <-peer.event.handshakeBegin.C:
+func expiredNewHandshake(peer *Peer) {
+	peer.device.log.Debug.Printf("%s: Retrying handshake because we stopped hearing back after %d seconds\n", peer, int((KeepaliveTimeout + RekeyTimeout).Seconds()))
+	/* We clear the endpoint address src address, in case this is the cause of trouble. */
+	peer.mutex.Lock()
+	if peer.endpoint != nil {
+		peer.endpoint.ClearSrc()
+	}
+	peer.mutex.Unlock()
+	peer.SendHandshakeInitiation(false)
 
-			if !enableHandshake {
-				continue
 }
 
-			logDebug.Println(peer, ": Event, Handshake Begin")
+func expiredZeroKeyMaterial(peer *Peer) {
-
+	peer.device.log.Debug.Printf(":%s Removing all keys, since we haven't received a new one in %d seconds\n", peer, int((RejectAfterTime * 3).Seconds()))
-			err := peer.sendNewHandshake()
-
-			// set timeout
-
-			jitter := time.Millisecond * time.Duration(rand.Int31n(334))
-			timerKeepalivePassive.Stop()
-			timerHandshakeTimeout.Reset(RekeyTimeout + jitter)
-
-			if err != nil {
-				logInfo.Println(peer, ": Failed to send handshake initiation", err)
-			} else {
-				logDebug.Println(peer, ": Send handshake initiation (initial)")
-			}
-
-			timerHandshakeDeadline.Reset(RekeyAttemptTime)
-
-			// disable further handshakes
-
-			peer.event.handshakeBegin.Clear()
-			enableHandshake = false
-
-		case <-peer.event.handshakeCompleted.C:
-
-			logInfo.Println(peer, ": Handshake completed")
-
-			atomic.StoreInt64(
-				&peer.stats.lastHandshakeNano,
-				time.Now().UnixNano(),
-			)
-
-			timerHandshakeTimeout.Stop()
-			timerHandshakeDeadline.Stop()
-			peer.timer.sendLastMinuteHandshake.Set(false)
-
-			// allow further handshakes
-
-			peer.event.handshakeBegin.Clear()
-			enableHandshake = true
-
-		/* timers */
-
-		case <-timerKeepalivePersistent.C:
-
-			interval := peer.persistentKeepaliveInterval
-			if interval > 0 {
-				logDebug.Println(peer, ": Send keep-alive (persistent)")
-				timerKeepalivePassive.Stop()
-				peer.SendKeepAlive()
-			}
-
-		case <-timerKeepalivePassive.C:
-
-			logDebug.Println(peer, ": Send keep-alive (passive)")
-
-			peer.SendKeepAlive()
-
-			if needAnotherKeepalive {
-				timerKeepalivePassive.Reset(KeepaliveTimeout)
-				needAnotherKeepalive = false
-			}
-
-		case <-timerZeroAllKeys.C:
-
-			logDebug.Println(peer, ": Clear all key-material (timer event)")
 
 	hs := &peer.handshake
 	hs.mutex.Lock()
@@ -280,76 +111,111 @@ func (peer *Peer) RoutineTimerHandler() {
 	kp := &peer.keyPairs
 	kp.mutex.Lock()
 
-			// remove key-pairs
-
 	if kp.previous != nil {
-				device.DeleteKeyPair(kp.previous)
+		peer.device.DeleteKeypair(kp.previous)
 		kp.previous = nil
 	}
 	if kp.current != nil {
-				device.DeleteKeyPair(kp.current)
+		peer.device.DeleteKeypair(kp.current)
 		kp.current = nil
 	}
 	if kp.next != nil {
-				device.DeleteKeyPair(kp.next)
+		peer.device.DeleteKeypair(kp.next)
 		kp.next = nil
 	}
 	kp.mutex.Unlock()
 
-			// zero out handshake
+	peer.device.indices.Delete(hs.localIndex)
-
-			device.indices.Delete(hs.localIndex)
 	hs.Clear()
 	hs.mutex.Unlock()
-
-		case <-timerHandshakeTimeout.C:
-
-			// allow new handshake to be send
-
-			enableHandshake = true
-
-			// clear source (in case this is causing problems)
-
-			peer.mutex.Lock()
-			if peer.endpoint != nil {
-				peer.endpoint.ClearSrc()
 }
-			peer.mutex.Unlock()
 
-			// send new handshake
+func expiredPersistentKeepalive(peer *Peer) {
+	if peer.persistentKeepaliveInterval > 0 {
+		if peer.timersActive() {
+			peer.timers.sendKeepalive.Del()
+		}
+		peer.SendKeepalive()
+	}
+}
 
-			err := peer.sendNewHandshake()
+/* Should be called after an authenticated data packet is sent. */
+func (peer *Peer) timersDataSent() {
+	if peer.timersActive() {
+		peer.timers.sendKeepalive.Del()
+	}
 
-			// set timeout
+	if peer.timersActive() && !peer.timers.newHandshake.isPending {
+		peer.timers.newHandshake.Mod(KeepaliveTimeout + RekeyTimeout)
+	}
+}
 
-			jitter := time.Millisecond * time.Duration(rand.Int31n(334))
+/* Should be called after an authenticated data packet is received. */
-			timerKeepalivePassive.Stop()
+func (peer *Peer) timersDataReceived() {
-			timerHandshakeTimeout.Reset(RekeyTimeout + jitter)
+	if peer.timersActive() {
-
+		if !peer.timers.sendKeepalive.isPending {
-			if err != nil {
+			peer.timers.sendKeepalive.Mod(KeepaliveTimeout)
-				logInfo.Println(peer, ": Failed to send handshake initiation", err)
 		} else {
-				logDebug.Println(peer, ": Send handshake initiation (subsequent)")
+			peer.timers.needAnotherKeepalive = true
-			}
-
-			// disable further handshakes
-
-			peer.event.handshakeBegin.Clear()
-			enableHandshake = false
-
-		case <-timerHandshakeDeadline.C:
-
-			// clear all queued packets and stop keep-alive
-
-			logInfo.Println(peer, ": Handshake negotiation timed-out")
-
-			peer.flushNonceQueue()
-			peer.event.flushNonceQueue.Fire()
-
-			// renable further handshakes
-
-			peer.event.handshakeBegin.Clear()
-			enableHandshake = true
 		}
 	}
 }
+
+/* Should be called after any type of authenticated packet is received -- keepalive or data. */
+func (peer *Peer) timersAnyAuthenticatedPacketReceived() {
+	if peer.timersActive() {
+		peer.timers.newHandshake.Del()
+	}
+}
+
+/* Should be called after a handshake initiation message is sent. */
+func (peer *Peer) timersHandshakeInitiated() {
+	if peer.timersActive() {
+		peer.timers.sendKeepalive.Del()
+		peer.timers.retransmitHandshake.Mod(RekeyTimeout + time.Millisecond*time.Duration(rand.Int31n(RekeyTimeoutJitterMaxMs)))
+	}
+}
+
+/* Should be called after a handshake response message is received and processed or when getting key confirmation via the first data message. */
+func (peer *Peer) timersHandshakeComplete() {
+	if peer.timersActive() {
+		peer.timers.retransmitHandshake.Del()
+	}
+	peer.timers.handshakeAttempts = 0
+	peer.timers.sentLastMinuteHandshake = false
+	atomic.StoreInt64(&peer.stats.lastHandshakeNano, time.Now().UnixNano())
+}
+
+/* Should be called after an ephemeral key is created, which is before sending a handshake response or after receiving a handshake response. */
+func (peer *Peer) timersSessionDerived() {
+	if peer.timersActive() {
+		peer.timers.zeroKeyMaterial.Mod(RejectAfterTime * 3)
+	}
+}
+
+/* Should be called before a packet with authentication -- data, keepalive, either handshake -- is sent, or after one is received. */
+func (peer *Peer) timersAnyAuthenticatedPacketTraversal() {
+	if peer.persistentKeepaliveInterval > 0 && peer.timersActive() {
+		peer.timers.persistentKeepalive.Mod(time.Duration(peer.persistentKeepaliveInterval) * time.Second)
+	}
+}
+
+func (peer *Peer) timersInit() {
+	peer.timers.retransmitHandshake = peer.NewTimer(expiredRetransmitHandshake)
+	peer.timers.sendKeepalive = peer.NewTimer(expiredSendKeepalive)
+	peer.timers.newHandshake = peer.NewTimer(expiredNewHandshake)
+	peer.timers.zeroKeyMaterial = peer.NewTimer(expiredZeroKeyMaterial)
+	peer.timers.persistentKeepalive = peer.NewTimer(expiredPersistentKeepalive)
+	peer.timers.handshakeAttempts = 0
+	peer.timers.sentLastMinuteHandshake = false
+	peer.timers.needAnotherKeepalive = false
+	peer.timers.lastSentHandshake = time.Now().Add(-(RekeyTimeout + time.Second))
+}
+
+func (peer *Peer) timersStop() {
+	peer.timers.retransmitHandshake.Del()
+	peer.timers.sendKeepalive.Del()
+	peer.timers.newHandshake.Del()
+	peer.timers.zeroKeyMaterial.Del()
+	peer.timers.persistentKeepalive.Del()
+}

uapi.go

@@ -256,8 +256,6 @@ func ipcSetOperation(device *Device, socket *bufio.ReadWriter) *IPCError {
 					logDebug.Println("UAPI: Created new peer:", peer)
 				}
 
-				peer.event.handshakePushDeadline.Fire()
-
 			case "remove":
 
 				// remove currently selected peer from device
@@ -288,8 +286,6 @@ func ipcSetOperation(device *Device, socket *bufio.ReadWriter) *IPCError {
 					return &IPCError{Code: ipcErrorInvalid}
 				}
 
-				peer.event.handshakePushDeadline.Fire()
-
 			case "endpoint":
 
 				// set endpoint destination
@@ -304,7 +300,6 @@ func ipcSetOperation(device *Device, socket *bufio.ReadWriter) *IPCError {
 						return err
 					}
 					peer.endpoint = endpoint
-					peer.event.handshakePushDeadline.Fire()
 					return nil
 				}()
 
@@ -315,7 +310,7 @@ func ipcSetOperation(device *Device, socket *bufio.ReadWriter) *IPCError {
 
 			case "persistent_keepalive_interval":
 
-				// update keep-alive interval
+				// update persistent keepalive interval
 
 				logDebug.Println("UAPI: Updating persistent_keepalive_interval for peer:", peer)
 
@@ -328,7 +323,7 @@ func ipcSetOperation(device *Device, socket *bufio.ReadWriter) *IPCError {
 				old := peer.persistentKeepaliveInterval
 				peer.persistentKeepaliveInterval = uint16(secs)
 
-				// send immediate keep-alive
+				// send immediate keepalive if we're turning it on and before it wasn't on
 
 				if old == 0 && secs != 0 {
 					if err != nil {
@@ -336,7 +331,7 @@ func ipcSetOperation(device *Device, socket *bufio.ReadWriter) *IPCError {
 						return &IPCError{Code: ipcErrorIO}
 					}
 					if device.isUp.Get() && !dummy {
-						peer.SendKeepAlive()
+						peer.SendKeepalive()
 					}
 				}