Initial working full exchange

The implementation is now capable of connecting to another
wireguard instance, complete a handshake and exchange transport
messages.

src/constants.go

@@ -21,5 +21,6 @@ const (
 	QueueInboundSize       = 1024
 	QueueHandshakeSize     = 1024
 	QueueHandshakeBusySize = QueueHandshakeSize / 8
-	MinMessageSize         = MessageTransportSize
+	MinMessageSize         = MessageTransportSize // keep-alive
+	MaxMessageSize         = 4096
 )

src/device.go

@@ -80,6 +80,7 @@ func NewDevice(tun TUNDevice, logLevel int) *Device {
 	device.queue.encryption = make(chan *QueueOutboundElement, QueueOutboundSize)
 	device.queue.handshake = make(chan QueueHandshakeElement, QueueHandshakeSize)
 	device.queue.decryption = make(chan *QueueInboundElement, QueueInboundSize)
+	device.queue.inbound = make(chan []byte, QueueInboundSize)
 
 	// prepare signals
 
@@ -94,6 +95,7 @@ func NewDevice(tun TUNDevice, logLevel int) *Device {
 	}
 	go device.RoutineReadFromTUN(tun)
 	go device.RoutineReceiveIncomming()
+	go device.RoutineWriteToTUN(tun)
 	return device
 }
 

src/handshake.go

@@ -12,9 +12,11 @@ import (
  * Used by initiator of handshake and with active keep-alive
  */
 func (peer *Peer) SendKeepAlive() bool {
+	elem := peer.device.NewOutboundElement()
+	elem.packet = nil
 	if len(peer.queue.nonce) == 0 {
 		select {
-		case peer.queue.nonce <- []byte{}:
+		case peer.queue.nonce <- elem:
 			return true
 		default:
 			return false
@@ -60,11 +62,10 @@ func (peer *Peer) KeepKeyFreshSending() {
  */
 func (peer *Peer) RoutineHandshakeInitiator() {
 	device := peer.device
-	buffer := make([]byte, 1024)
 	logger := device.log.Debug
 	timeout := stoppedTimer()
 
-	var work *QueueOutboundElement
+	var elem *QueueOutboundElement
 
 	logger.Println("Routine, handshake initator, started for peer", peer.id)
 
@@ -94,25 +95,25 @@ func (peer *Peer) RoutineHandshakeInitiator() {
 
 				// create initiation
 
-				if work != nil {
+				if elem != nil {
-					work.mutex.Lock()
+					elem.Drop()
-					work.packet = nil
-					work.mutex.Unlock()
 				}
-				work = new(QueueOutboundElement)
+				elem = device.NewOutboundElement()
+
 				msg, err := device.CreateMessageInitiation(peer)
 				if err != nil {
 					device.log.Error.Println("Failed to create initiation message:", err)
 					break
 				}
 
-				// schedule for sending
+				// marshal & schedule for sending
 
-				writer := bytes.NewBuffer(buffer[:0])
+				writer := bytes.NewBuffer(elem.data[:0])
 				binary.Write(writer, binary.LittleEndian, msg)
-				work.packet = writer.Bytes()
+				elem.packet = writer.Bytes()
-				peer.mac.AddMacs(work.packet)
+				peer.mac.AddMacs(elem.packet)
-				peer.InsertOutbound(work)
+				println(elem)
+				addToOutboundQueue(peer.queue.outbound, elem)
 
 				if attempts == 0 {
 					deadline = time.Now().Add(MaxHandshakeAttemptTime)
@@ -132,9 +133,11 @@ func (peer *Peer) RoutineHandshakeInitiator() {
 					return
 
 				case <-peer.signal.handshakeCompleted:
+					device.log.Debug.Println("Handshake complete")
 					break HandshakeLoop
 
 				case <-timeout.C:
+					device.log.Debug.Println("Timeout")
 					if deadline.Before(time.Now().Add(RekeyTimeout)) {
 						peer.signal.flushNonceQueue <- struct{}{}
 						if !peer.timer.sendKeepalive.Stop() {

src/keypair.go

@@ -7,8 +7,7 @@ import (
 )
 
 type KeyPair struct {
-	recv        cipher.AEAD
+	receive     cipher.AEAD
-	recvNonce   uint64
 	send        cipher.AEAD
 	sendNonce   uint64
 	isInitiator bool

src/noise_protocol.go

@@ -446,10 +446,10 @@ func (peer *Peer) NewKeyPair() *KeyPair {
 
 	keyPair := new(KeyPair)
 	keyPair.send, _ = chacha20poly1305.New(sendKey[:])
-	keyPair.recv, _ = chacha20poly1305.New(recvKey[:])
+	keyPair.receive, _ = chacha20poly1305.New(recvKey[:])
 	keyPair.sendNonce = 0
-	keyPair.recvNonce = 0
 	keyPair.created = time.Now()
+	keyPair.isInitiator = isInitiator
 	keyPair.localIndex = peer.handshake.localIndex
 	keyPair.remoteIndex = peer.handshake.remoteIndex
 
@@ -462,7 +462,7 @@ func (peer *Peer) NewKeyPair() *KeyPair {
 	})
 	handshake.localIndex = 0
 
-	// start timer for keypair
+	// TODO: start timer for keypair (clearing)
 
 	// rotate key pairs
 
@@ -473,7 +473,7 @@ func (peer *Peer) NewKeyPair() *KeyPair {
 		if isInitiator {
 			if kp.previous != nil {
 				kp.previous.send = nil
-				kp.previous.recv = nil
+				kp.previous.receive = nil
 				peer.device.indices.Delete(kp.previous.localIndex)
 			}
 			kp.previous = kp.current

src/peer.go

@@ -35,7 +35,7 @@ type Peer struct {
 		handshakeTimeout *time.Timer
 	}
 	queue struct {
-		nonce    chan []byte                // nonce / pre-handshake queue
+		nonce    chan *QueueOutboundElement // nonce / pre-handshake queue
 		outbound chan *QueueOutboundElement // sequential ordering of work
 		inbound  chan *QueueInboundElement  // sequential ordering of work
 	}
@@ -78,9 +78,9 @@ func (device *Device) NewPeer(pk NoisePublicKey) *Peer {
 
 	// prepare queuing
 
-	peer.queue.nonce = make(chan []byte, QueueOutboundSize)
+	peer.queue.nonce = make(chan *QueueOutboundElement, QueueOutboundSize)
-	peer.queue.inbound = make(chan *QueueInboundElement, QueueInboundSize)
 	peer.queue.outbound = make(chan *QueueOutboundElement, QueueOutboundSize)
+	peer.queue.inbound = make(chan *QueueInboundElement, QueueInboundSize)
 
 	// prepare signaling
 

src/receive.go

@@ -31,17 +31,39 @@ type QueueInboundElement struct {
 
 func (elem *QueueInboundElement) Drop() {
 	atomic.StoreUint32(&elem.state, ElementStateDropped)
-	elem.mutex.Unlock()
+}
+
+func (elem *QueueInboundElement) IsDropped() bool {
+	return atomic.LoadUint32(&elem.state) == ElementStateDropped
+}
+
+func addToInboundQueue(
+	queue chan *QueueInboundElement,
+	element *QueueInboundElement,
+) {
+	for {
+		select {
+		case queue <- element:
+			return
+		default:
+			select {
+			case old := <-queue:
+				old.Drop()
+			default:
+			}
+		}
+	}
 }
 
 func (device *Device) RoutineReceiveIncomming() {
-	var packet []byte
 
 	debugLog := device.log.Debug
 	debugLog.Println("Routine, receive incomming, started")
 
 	errorLog := device.log.Error
 
+	var buffer []byte // unsliced buffer
+
 	for {
 
 		// check if stopped
@@ -54,28 +76,28 @@ func (device *Device) RoutineReceiveIncomming() {
 
 		// read next datagram
 
-		if packet == nil {
+		if buffer == nil {
-			packet = make([]byte, 1<<16)
+			buffer = make([]byte, MaxMessageSize)
 		}
 
 		device.net.mutex.RLock()
 		conn := device.net.conn
 		device.net.mutex.RUnlock()
+		if conn == nil {
+			time.Sleep(time.Second)
+			continue
+		}
 
 		conn.SetReadDeadline(time.Now().Add(time.Second))
 
-		size, raddr, err := conn.ReadFromUDP(packet)
+		size, raddr, err := conn.ReadFromUDP(buffer)
-		if err != nil {
+		if err != nil || size < MinMessageSize {
-			continue
-		}
-		if size < MinMessageSize {
 			continue
 		}
 
 		// handle packet
 
-		packet = packet[:size]
+		packet := buffer[:size]
-		debugLog.Println("GOT:", packet)
 		msgType := binary.LittleEndian.Uint32(packet[:4])
 
 		func() {
@@ -112,6 +134,7 @@ func (device *Device) RoutineReceiveIncomming() {
 
 				// add to handshake queue
 
+				buffer = nil
 				device.queue.handshake <- QueueHandshakeElement{
 					msgType: msgType,
 					packet:  packet,
@@ -137,8 +160,6 @@ func (device *Device) RoutineReceiveIncomming() {
 
 			case MessageTransportType:
 
-				debugLog.Println("DEBUG: Got transport")
-
 				// lookup key pair
 
 				if len(packet) < MessageTransportSize {
@@ -169,42 +190,15 @@ func (device *Device) RoutineReceiveIncomming() {
 				work.state = ElementStateOkay
 				work.mutex.Lock()
 
-				// add to parallel decryption queue
+				// add to decryption queues
 
-				func() {
+				addToInboundQueue(device.queue.decryption, work)
-					for {
+				addToInboundQueue(peer.queue.inbound, work)
-						select {
+				buffer = nil
-						case device.queue.decryption <- work:
-							return
-						default:
-							select {
-							case elem := <-device.queue.decryption:
-								elem.Drop()
-							default:
-							}
-						}
-					}
-				}()
-
-				// add to sequential inbound queue
-
-				func() {
-					for {
-						select {
-						case peer.queue.inbound <- work:
-							break
-						default:
-							select {
-							case elem := <-peer.queue.inbound:
-								elem.Drop()
-							default:
-							}
-						}
-					}
-				}()
 
 			default:
 				// unknown message type
+				debugLog.Println("Got unknown message from:", raddr)
 			}
 		}()
 	}
@@ -214,6 +208,9 @@ func (device *Device) RoutineDecryption() {
 	var elem *QueueInboundElement
 	var nonce [chacha20poly1305.NonceSize]byte
 
+	logDebug := device.log.Debug
+	logDebug.Println("Routine, decryption, started for device")
+
 	for {
 		select {
 		case elem = <-device.queue.decryption:
@@ -223,31 +220,25 @@ func (device *Device) RoutineDecryption() {
 
 		// check if dropped
 
-		state := atomic.LoadUint32(&elem.state)
+		if elem.IsDropped() {
-		if state != ElementStateOkay {
+			elem.mutex.Unlock()
 			continue
 		}
 
 		// split message into fields
 
-		counter := binary.LittleEndian.Uint64(
+		counter := elem.packet[MessageTransportOffsetCounter:MessageTransportOffsetContent]
-			elem.packet[MessageTransportOffsetCounter:MessageTransportOffsetContent],
-		)
 		content := elem.packet[MessageTransportOffsetContent:]
 
 		// decrypt with key-pair
 
 		var err error
-		binary.LittleEndian.PutUint64(nonce[4:], counter)
+		copy(nonce[4:], counter)
-		elem.packet, err = elem.keyPair.recv.Open(elem.packet[:0], nonce[:], content, nil)
+		elem.counter = binary.LittleEndian.Uint64(counter)
+		elem.packet, err = elem.keyPair.receive.Open(elem.packet[:0], nonce[:], content, nil)
 		if err != nil {
 			elem.Drop()
-			continue
 		}
-
-		// release to consumer
-
-		elem.counter = counter
 		elem.mutex.Unlock()
 	}
 }
@@ -261,6 +252,7 @@ func (device *Device) RoutineHandshake() {
 	logInfo := device.log.Info
 	logError := device.log.Error
 	logDebug := device.log.Debug
+	logDebug.Println("Routine, handshake routine, started for device")
 
 	var elem QueueHandshakeElement
 
@@ -332,13 +324,15 @@ func (device *Device) RoutineHandshake() {
 				}
 				sendSignal(peer.signal.handshakeCompleted)
 				logDebug.Println("Recieved valid response message for peer", peer.id)
-				peer.NewKeyPair()
+				kp := peer.NewKeyPair()
+				if kp == nil {
+					logDebug.Println("Failed to derieve key-pair")
+				}
 				peer.SendKeepAlive()
 
 			default:
 				device.log.Error.Println("Invalid message type in handshake queue")
 			}
-
 		}()
 	}
 }
@@ -348,7 +342,6 @@ func (peer *Peer) RoutineSequentialReceiver() {
 
 	device := peer.device
 	logDebug := device.log.Debug
-
 	logDebug.Println("Routine, sequential receiver, started for peer", peer.id)
 
 	for {
@@ -359,20 +352,15 @@ func (peer *Peer) RoutineSequentialReceiver() {
 			return
 		case elem = <-peer.queue.inbound:
 		}
+
 		elem.mutex.Lock()
-
+		if elem.IsDropped() {
-		// check if dropped
-
-		logDebug.Println("MESSSAGE:", elem)
-
-		state := atomic.LoadUint32(&elem.state)
-		if state != ElementStateOkay {
 			continue
 		}
 
 		// check for replay
 
-		// strip padding
+		// update timers
 
 		// check for keep-alive
 
@@ -380,26 +368,30 @@ func (peer *Peer) RoutineSequentialReceiver() {
 			continue
 		}
 
+		// strip padding
+
 		// insert into inbound TUN queue
 
 		device.queue.inbound <- elem.packet
-	}
 
+		// update key material
+	}
 }
 
 func (device *Device) RoutineWriteToTUN(tun TUNDevice) {
-	for {
+	logError := device.log.Error
-		var packet []byte
+	logDebug := device.log.Debug
+	logDebug.Println("Routine, sequential tun writer, started")
 
+	for {
 		select {
 		case <-device.signal.stop:
-		case packet = <-device.queue.inbound:
+			return
-		}
+		case packet := <-device.queue.inbound:
-
+			_, err := tun.Write(packet)
-		size, err := tun.Write(packet)
+			if err != nil {
-		device.log.Debug.Println("DEBUG:", size, err)
+				logError.Println("Failed to write packet to TUN device:", err)
-		if err != nil {
+			}
-
 		}
 	}
 }

src/send.go

@@ -25,14 +25,19 @@ import (
  *
  * The sequential consumers will attempt to take the lock,
  * workers release lock when they have completed work on the packet.
+ *
+ * If the element is inserted into the "encryption queue",
+ * the content is preceeded by enough "junk" to contain the header
+ * (to allow the constuction of transport messages in-place)
  */
 type QueueOutboundElement struct {
 	state   uint32
 	mutex   sync.Mutex
-	packet  []byte
+	data    [MaxMessageSize]byte
-	nonce   uint64
+	packet  []byte   // slice of packet (sending)
-	keyPair *KeyPair
+	nonce   uint64   // nonce for encryption
-	peer    *Peer
+	keyPair *KeyPair // key-pair for encryption
+	peer    *Peer    // related peer
 }
 
 func (peer *Peer) FlushNonceQueue() {
@@ -46,18 +51,9 @@ func (peer *Peer) FlushNonceQueue() {
 	}
 }
 
-func (peer *Peer) InsertOutbound(elem *QueueOutboundElement) {
+func (device *Device) NewOutboundElement() *QueueOutboundElement {
-	for {
+	elem := new(QueueOutboundElement) // TODO: profile, consider sync.Pool
-		select {
+	return elem
-		case peer.queue.outbound <- elem:
-			return
-		default:
-			select {
-			case <-peer.queue.outbound:
-			default:
-			}
-		}
-	}
 }
 
 func (elem *QueueOutboundElement) Drop() {
@@ -68,53 +64,74 @@ func (elem *QueueOutboundElement) IsDropped() bool {
 	return atomic.LoadUint32(&elem.state) == ElementStateDropped
 }
 
+func addToOutboundQueue(
+	queue chan *QueueOutboundElement,
+	element *QueueOutboundElement,
+) {
+	for {
+		select {
+		case queue <- element:
+			return
+		default:
+			select {
+			case old := <-queue:
+				old.Drop()
+			default:
+			}
+		}
+	}
+}
+
 /* Reads packets from the TUN and inserts
  * into nonce queue for peer
  *
  * Obs. Single instance per TUN device
  */
 func (device *Device) RoutineReadFromTUN(tun TUNDevice) {
-	if tun.MTU() == 0 {
+	if tun == nil {
-		// Dummy
+		// dummy
 		return
 	}
 
+	elem := device.NewOutboundElement()
+
 	device.log.Debug.Println("Routine, TUN Reader: started")
 	for {
 		// read packet
 
-		packet := make([]byte, 1<<16) // TODO: Fix & avoid dynamic allocation
+		if elem == nil {
-		size, err := tun.Read(packet)
+			elem = device.NewOutboundElement()
+		}
+
+		elem.packet = elem.data[MessageTransportHeaderSize:]
+		size, err := tun.Read(elem.packet)
 		if err != nil {
 			device.log.Error.Println("Failed to read packet from TUN device:", err)
 			continue
 		}
-		packet = packet[:size]
+		elem.packet = elem.packet[:size]
-		if len(packet) < IPv4headerSize {
+		if len(elem.packet) < IPv4headerSize {
-			device.log.Error.Println("Packet too short, length:", len(packet))
+			device.log.Error.Println("Packet too short, length:", size)
 			continue
 		}
 
 		// lookup peer
 
 		var peer *Peer
-		switch packet[0] >> 4 {
+		switch elem.packet[0] >> 4 {
 		case IPv4version:
-			dst := packet[IPv4offsetDst : IPv4offsetDst+net.IPv4len]
+			dst := elem.packet[IPv4offsetDst : IPv4offsetDst+net.IPv4len]
 			peer = device.routingTable.LookupIPv4(dst)
-			device.log.Debug.Println("New IPv4 packet:", packet, dst)
 
 		case IPv6version:
-			dst := packet[IPv6offsetDst : IPv6offsetDst+net.IPv6len]
+			dst := elem.packet[IPv6offsetDst : IPv6offsetDst+net.IPv6len]
 			peer = device.routingTable.LookupIPv6(dst)
-			device.log.Debug.Println("New IPv6 packet:", packet, dst)
 
 		default:
 			device.log.Debug.Println("Receieved packet with unknown IP version")
 		}
 
 		if peer == nil {
-			device.log.Debug.Println("No peer configured for IP")
 			continue
 		}
 		if peer.endpoint == nil {
@@ -124,18 +141,9 @@ func (device *Device) RoutineReadFromTUN(tun TUNDevice) {
 
 		// insert into nonce/pre-handshake queue
 
-		for {
+		addToOutboundQueue(peer.queue.nonce, elem)
-			select {
+		elem = nil
-			case peer.queue.nonce <- packet:
+
-			default:
-				select {
-				case <-peer.queue.nonce:
-				default:
-				}
-				continue
-			}
-			break
-		}
 	}
 }
 
@@ -148,8 +156,8 @@ func (device *Device) RoutineReadFromTUN(tun TUNDevice) {
  * Obs. A single instance per peer
  */
 func (peer *Peer) RoutineNonce() {
-	var packet []byte
 	var keyPair *KeyPair
+	var elem *QueueOutboundElement
 
 	device := peer.device
 	logger := device.log.Debug
@@ -163,9 +171,9 @@ func (peer *Peer) RoutineNonce() {
 
 			// wait for packet
 
-			if packet == nil {
+			if elem == nil {
 				select {
-				case packet = <-peer.queue.nonce:
+				case elem = <-peer.queue.nonce:
 				case <-peer.signal.stop:
 					return
 				}
@@ -198,7 +206,7 @@ func (peer *Peer) RoutineNonce() {
 				case <-peer.signal.flushNonceQueue:
 					logger.Println("Clearing queue for peer", peer.id)
 					peer.FlushNonceQueue()
-					packet = nil
+					elem = nil
 					goto NextPacket
 
 				case <-peer.signal.stop:
@@ -208,36 +216,20 @@ func (peer *Peer) RoutineNonce() {
 
 			// process current packet
 
-			if packet != nil {
+			if elem != nil {
 
 				// create work element
 
-				work := new(QueueOutboundElement) // TODO: profile, maybe use pool
+				elem.keyPair = keyPair
-				work.keyPair = keyPair
+				elem.nonce = atomic.AddUint64(&keyPair.sendNonce, 1) - 1
-				work.packet = packet
+				elem.peer = peer
-				work.nonce = atomic.AddUint64(&keyPair.sendNonce, 1) - 1
+				elem.mutex.Lock()
-				work.peer = peer
-				work.mutex.Lock()
 
-				packet = nil
+				// add to parallel processing and sequential consuming queue
 
-				// drop packets until there is space
+				addToOutboundQueue(device.queue.encryption, elem)
-
+				addToOutboundQueue(peer.queue.outbound, elem)
-				func() {
+				elem = nil
-					for {
-						select {
-						case peer.device.queue.encryption <- work:
-							return
-						default:
-							select {
-							case elem := <-peer.device.queue.encryption:
-								elem.Drop()
-							default:
-							}
-						}
-					}
-				}()
-				peer.queue.outbound <- work
 			}
 		}
 	}()
@@ -257,42 +249,38 @@ func (device *Device) RoutineEncryption() {
 			continue
 		}
 
-		// pad packet
+		// populate header fields
 
-		padding := device.mtu - len(work.packet) - MessageTransportSize
+		func() {
-		if padding < 0 {
+			header := work.data[:MessageTransportHeaderSize]
-			work.Drop()
-			continue
-		}
 
-		for n := 0; n < padding; n += 1 {
+			fieldType := header[0:4]
-			work.packet = append(work.packet, 0)
+			fieldReceiver := header[4:8]
-		}
+			fieldNonce := header[8:16]
-		content := work.packet[MessageTransportHeaderSize:]
-		copy(content, work.packet)
 
-		// prepare header
+			binary.LittleEndian.PutUint32(fieldType, MessageTransportType)
-
+			binary.LittleEndian.PutUint32(fieldReceiver, work.keyPair.remoteIndex)
-		binary.LittleEndian.PutUint32(work.packet[:4], MessageTransportType)
+			binary.LittleEndian.PutUint64(fieldNonce, work.nonce)
-		binary.LittleEndian.PutUint32(work.packet[4:8], work.keyPair.remoteIndex)
+		}()
-		binary.LittleEndian.PutUint64(work.packet[8:16], work.nonce)
-
-		device.log.Debug.Println(work.packet, work.nonce)
 
 		// encrypt content
 
-		binary.LittleEndian.PutUint64(nonce[4:], work.nonce)
+		func() {
-		work.keyPair.send.Seal(
+			binary.LittleEndian.PutUint64(nonce[4:], work.nonce)
-			content[:0],
+			work.packet = work.keyPair.send.Seal(
-			nonce[:],
+				work.packet[:0],
-			content,
+				nonce[:],
-			nil,
+				work.packet,
-		)
+				nil,
-		work.mutex.Unlock()
+			)
+			work.mutex.Unlock()
+		}()
 
-		device.log.Debug.Println(work.packet, work.nonce)
+		// reslice to include header
 
-		// initiate new handshake
+		work.packet = work.data[:MessageTransportHeaderSize+len(work.packet)]
+
+		// refresh key if necessary
 
 		work.peer.KeepKeyFreshSending()
 	}
@@ -340,8 +328,6 @@ func (peer *Peer) RoutineSequentialSender() {
 					return
 				}
 
-				logger.Println(work.packet)
-
 				_, err := device.net.conn.WriteToUDP(work.packet, peer.endpoint)
 				if err != nil {
 					return