Begin work on outbound packet flow

9 files changed, 315 insertions, 95 deletions

diff --git a/src/cookie.go b/src/cookie.go
new file mode 100644
index 0000000..a6987a2
--- /dev/null
+++ b/src/cookie.go
@@ -0,0 +1,39 @@
+package main
+
+import (
+	"errors"
+	"golang.org/x/crypto/blake2s"
+)
+
+func CalculateCookie(peer *Peer, msg []byte) {
+	size := len(msg)
+
+	if size < blake2s.Size128*2 {
+		panic(errors.New("bug: message too short"))
+	}
+
+	startMac1 := size - (blake2s.Size128 * 2)
+	startMac2 := size - blake2s.Size128
+
+	mac1 := msg[startMac1 : startMac1+blake2s.Size128]
+	mac2 := msg[startMac2 : startMac2+blake2s.Size128]
+
+	peer.mutex.RLock()
+	defer peer.mutex.RUnlock()
+
+	// set mac1
+
+	func() {
+		mac, _ := blake2s.New128(peer.macKey[:])
+		mac.Write(msg[:startMac1])
+		mac.Sum(mac1[:0])
+	}()
+
+	// set mac2
+
+	if peer.cookie != nil {
+		mac, _ := blake2s.New128(peer.cookie)
+		mac.Write(msg[:startMac2])
+		mac.Sum(mac2[:0])
+	}
+}
diff --git a/src/device.go b/src/device.go
index 9969034..ce10a63 100644
--- a/src/device.go
+++ b/src/device.go
@@ -1,18 +1,22 @@
 package main
 
 import (
+	"log"
 	"sync"
 )
 
 type Device struct {
-	mutex        sync.RWMutex
-	peers        map[NoisePublicKey]*Peer
-	indices      IndexTable
-	privateKey   NoisePrivateKey
-	publicKey    NoisePublicKey
-	fwMark       uint32
-	listenPort   uint16
-	routingTable RoutingTable
+	mtu               int
+	mutex             sync.RWMutex
+	peers             map[NoisePublicKey]*Peer
+	indices           IndexTable
+	privateKey        NoisePrivateKey
+	publicKey         NoisePublicKey
+	fwMark            uint32
+	listenPort        uint16
+	routingTable      RoutingTable
+	logger            log.Logger
+	queueWorkOutbound chan *OutboundWorkQueueElement
 }
 
 func (device *Device) SetPrivateKey(sk NoisePrivateKey) {
diff --git a/src/keypair.go b/src/keypair.go
index e434c74..e7961a8 100644
--- a/src/keypair.go
+++ b/src/keypair.go
@@ -2,11 +2,20 @@ package main
 
 import (
 	"crypto/cipher"
+	"sync"
 )
 
 type KeyPair struct {
 	recv      cipher.AEAD
-	recvNonce NoiseNonce
+	recvNonce uint64
 	send      cipher.AEAD
-	sendNonce NoiseNonce
+	sendNonce uint64
+}
+
+type KeyPairs struct {
+	mutex      sync.RWMutex
+	current    *KeyPair
+	previous   *KeyPair
+	next       *KeyPair
+	newKeyPair chan bool
 }
diff --git a/src/main.go b/src/main.go
index af336f0..b6f6deb 100644
--- a/src/main.go
+++ b/src/main.go
@@ -1,6 +1,8 @@
 package main
 
-import "fmt"
+import (
+	"fmt"
+)
 
 func main() {
 	fd, err := CreateTUN("test0")
@@ -8,9 +10,9 @@ func main() {
 
 	queue := make(chan []byte, 1000)
 
-	var device Device
+	// var device Device
 
-	go OutgoingRoutingWorker(&device, queue)
+	// go OutgoingRoutingWorker(&device, queue)
 
 	for {
 		tmp := make([]byte, 1<<16)
diff --git a/src/noise_protocol.go b/src/noise_protocol.go
index 7f26cf1..a16908a 100644
--- a/src/noise_protocol.go
+++ b/src/noise_protocol.go
@@ -9,9 +9,9 @@ import (
 )
 
 const (
-	HandshakeReset = iota
-	HandshakeInitialCreated
-	HandshakeInitialConsumed
+	HandshakeZeroed = iota
+	HandshakeInitiationCreated
+	HandshakeInitiationConsumed
 	HandshakeResponseCreated
 	HandshakeResponseConsumed
 )
@@ -24,13 +24,19 @@ const (
 )
 
 const (
-	MessageInitalType         = 1
+	MessageInitiationType     = 1
 	MessageResponseType       = 2
 	MessageCookieResponseType = 3
 	MessageTransportType      = 4
 )
 
-type MessageInital struct {
+/* Type is an 8-bit field, followed by 3 nul bytes,
+ * by marshalling the messages in little-endian byteorder
+ * we can treat these as a 32-bit int
+ *
+ */
+
+type MessageInitiation struct {
 	Type      uint32
 	Sender    uint32
 	Ephemeral NoisePublicKey
@@ -73,9 +79,9 @@ type Handshake struct {
 }
 
 var (
-	ZeroNonce      [chacha20poly1305.NonceSize]byte
 	InitalChainKey [blake2s.Size]byte
 	InitalHash     [blake2s.Size]byte
+	ZeroNonce      [chacha20poly1305.NonceSize]byte
 )
 
 func init() {
@@ -83,23 +89,23 @@ func init() {
 	InitalHash = blake2s.Sum256(append(InitalChainKey[:], []byte(WGIdentifier)...))
 }
 
-func addToChainKey(c [blake2s.Size]byte, data []byte) [blake2s.Size]byte {
+func mixKey(c [blake2s.Size]byte, data []byte) [blake2s.Size]byte {
 	return KDF1(c[:], data)
 }
 
-func addToHash(h [blake2s.Size]byte, data []byte) [blake2s.Size]byte {
+func mixHash(h [blake2s.Size]byte, data []byte) [blake2s.Size]byte {
 	return blake2s.Sum256(append(h[:], data...))
 }
 
-func (h *Handshake) addToHash(data []byte) {
-	h.hash = addToHash(h.hash, data)
+func (h *Handshake) mixHash(data []byte) {
+	h.hash = mixHash(h.hash, data)
 }
 
-func (h *Handshake) addToChainKey(data []byte) {
-	h.chainKey = addToChainKey(h.chainKey, data)
+func (h *Handshake) mixKey(data []byte) {
+	h.chainKey = mixKey(h.chainKey, data)
 }
 
-func (device *Device) CreateMessageInitial(peer *Peer) (*MessageInital, error) {
+func (device *Device) CreateMessageInitiation(peer *Peer) (*MessageInitiation, error) {
 	handshake := &peer.handshake
 	handshake.mutex.Lock()
 	defer handshake.mutex.Unlock()
@@ -108,7 +114,7 @@ func (device *Device) CreateMessageInitial(peer *Peer) (*MessageInital, error) {
 
 	var err error
 	handshake.chainKey = InitalChainKey
-	handshake.hash = addToHash(InitalHash, handshake.remoteStatic[:])
+	handshake.hash = mixHash(InitalHash, handshake.remoteStatic[:])
 	handshake.localEphemeral, err = newPrivateKey()
 	if err != nil {
 		return nil, err
@@ -116,9 +122,9 @@ func (device *Device) CreateMessageInitial(peer *Peer) (*MessageInital, error) {
 
 	// assign index
 
-	var msg MessageInital
+	var msg MessageInitiation
 
-	msg.Type = MessageInitalType
+	msg.Type = MessageInitiationType
 	msg.Ephemeral = handshake.localEphemeral.publicKey()
 	handshake.localIndex, err = device.indices.NewIndex(peer)
 
@@ -127,10 +133,10 @@ func (device *Device) CreateMessageInitial(peer *Peer) (*MessageInital, error) {
 	}
 
 	msg.Sender = handshake.localIndex
-	handshake.addToChainKey(msg.Ephemeral[:])
-	handshake.addToHash(msg.Ephemeral[:])
+	handshake.mixKey(msg.Ephemeral[:])
+	handshake.mixHash(msg.Ephemeral[:])
 
-	// encrypt identity key
+	// encrypt static key
 
 	func() {
 		var key [chacha20poly1305.KeySize]byte
@@ -139,7 +145,7 @@ func (device *Device) CreateMessageInitial(peer *Peer) (*MessageInital, error) {
 		aead, _ := chacha20poly1305.New(key[:])
 		aead.Seal(msg.Static[:0], ZeroNonce[:], device.publicKey[:], handshake.hash[:])
 	}()
-	handshake.addToHash(msg.Static[:])
+	handshake.mixHash(msg.Static[:])
 
 	// encrypt timestamp
 
@@ -154,22 +160,22 @@ func (device *Device) CreateMessageInitial(peer *Peer) (*MessageInital, error) {
 		aead.Seal(msg.Timestamp[:0], ZeroNonce[:], timestamp[:], handshake.hash[:])
 	}()
 
-	handshake.addToHash(msg.Timestamp[:])
-	handshake.state = HandshakeInitialCreated
+	handshake.mixHash(msg.Timestamp[:])
+	handshake.state = HandshakeInitiationCreated
 
 	return &msg, nil
 }
 
-func (device *Device) ConsumeMessageInitial(msg *MessageInital) *Peer {
-	if msg.Type != MessageInitalType {
-		panic(errors.New("bug: invalid inital message type"))
+func (device *Device) ConsumeMessageInitiation(msg *MessageInitiation) *Peer {
+	if msg.Type != MessageInitiationType {
+		return nil
 	}
 
-	hash := addToHash(InitalHash, device.publicKey[:])
-	hash = addToHash(hash, msg.Ephemeral[:])
-	chainKey := addToChainKey(InitalChainKey, msg.Ephemeral[:])
+	hash := mixHash(InitalHash, device.publicKey[:])
+	hash = mixHash(hash, msg.Ephemeral[:])
+	chainKey := mixKey(InitalChainKey, msg.Ephemeral[:])
 
-	// decrypt identity key
+	// decrypt static key
 
 	var err error
 	var peerPK NoisePublicKey
@@ -183,7 +189,7 @@ func (device *Device) ConsumeMessageInitial(msg *MessageInital) *Peer {
 	if err != nil {
 		return nil
 	}
-	hash = addToHash(hash, msg.Static[:])
+	hash = mixHash(hash, msg.Static[:])
 
 	// find peer
 
@@ -210,7 +216,7 @@ func (device *Device) ConsumeMessageInitial(msg *MessageInital) *Peer {
 	if err != nil {
 		return nil
 	}
-	hash = addToHash(hash, msg.Timestamp[:])
+	hash = mixHash(hash, msg.Timestamp[:])
 
 	// check for replay attack
 
@@ -218,7 +224,7 @@ func (device *Device) ConsumeMessageInitial(msg *MessageInital) *Peer {
 		return nil
 	}
 
-	// check for flood attack
+	// TODO: check for flood attack
 
 	// update handshake state
 
@@ -227,7 +233,7 @@ func (device *Device) ConsumeMessageInitial(msg *MessageInital) *Peer {
 	handshake.remoteIndex = msg.Sender
 	handshake.remoteEphemeral = msg.Ephemeral
 	handshake.lastTimestamp = timestamp
-	handshake.state = HandshakeInitialConsumed
+	handshake.state = HandshakeInitiationConsumed
 	return peer
 }
 
@@ -236,8 +242,8 @@ func (device *Device) CreateMessageResponse(peer *Peer) (*MessageResponse, error
 	handshake.mutex.Lock()
 	defer handshake.mutex.Unlock()
 
-	if handshake.state != HandshakeInitialConsumed {
-		panic(errors.New("bug: handshake initation must be consumed first"))
+	if handshake.state != HandshakeInitiationConsumed {
+		return nil, errors.New("handshake initation must be consumed first")
 	}
 
 	// assign index
@@ -260,13 +266,13 @@ func (device *Device) CreateMessageResponse(peer *Peer) (*MessageResponse, error
 		return nil, err
 	}
 	msg.Ephemeral = handshake.localEphemeral.publicKey()
-	handshake.addToHash(msg.Ephemeral[:])
+	handshake.mixHash(msg.Ephemeral[:])
 
 	func() {
 		ss := handshake.localEphemeral.sharedSecret(handshake.remoteEphemeral)
-		handshake.addToChainKey(ss[:])
+		handshake.mixKey(ss[:])
 		ss = handshake.localEphemeral.sharedSecret(handshake.remoteStatic)
-		handshake.addToChainKey(ss[:])
+		handshake.mixKey(ss[:])
 	}()
 
 	// add preshared key (psk)
@@ -274,12 +280,12 @@ func (device *Device) CreateMessageResponse(peer *Peer) (*MessageResponse, error
 	var tau [blake2s.Size]byte
 	var key [chacha20poly1305.KeySize]byte
 	handshake.chainKey, tau, key = KDF3(handshake.chainKey[:], handshake.presharedKey[:])
-	handshake.addToHash(tau[:])
+	handshake.mixHash(tau[:])
 
 	func() {
 		aead, _ := chacha20poly1305.New(key[:])
 		aead.Seal(msg.Empty[:0], ZeroNonce[:], nil, handshake.hash[:])
-		handshake.addToHash(msg.Empty[:])
+		handshake.mixHash(msg.Empty[:])
 	}()
 
 	handshake.state = HandshakeResponseCreated
@@ -288,7 +294,7 @@ func (device *Device) CreateMessageResponse(peer *Peer) (*MessageResponse, error
 
 func (device *Device) ConsumeMessageResponse(msg *MessageResponse) *Peer {
 	if msg.Type != MessageResponseType {
-		panic(errors.New("bug: invalid message type"))
+		return nil
 	}
 
 	// lookup handshake by reciever
@@ -300,20 +306,20 @@ func (device *Device) ConsumeMessageResponse(msg *MessageResponse) *Peer {
 	handshake := &peer.handshake
 	handshake.mutex.Lock()
 	defer handshake.mutex.Unlock()
-	if handshake.state != HandshakeInitialCreated {
+	if handshake.state != HandshakeInitiationCreated {
 		return nil
 	}
 
 	// finish 3-way DH
 
-	hash := addToHash(handshake.hash, msg.Ephemeral[:])
+	hash := mixHash(handshake.hash, msg.Ephemeral[:])
 	chainKey := handshake.chainKey
 
 	func() {
 		ss := handshake.localEphemeral.sharedSecret(msg.Ephemeral)
-		chainKey = addToChainKey(chainKey, ss[:])
+		chainKey = mixKey(chainKey, ss[:])
 		ss = device.privateKey.sharedSecret(msg.Ephemeral)
-		chainKey = addToChainKey(chainKey, ss[:])
+		chainKey = mixKey(chainKey, ss[:])
 	}()
 
 	// add preshared key (psk)
@@ -321,7 +327,7 @@ func (device *Device) ConsumeMessageResponse(msg *MessageResponse) *Peer {
 	var tau [blake2s.Size]byte
 	var key [chacha20poly1305.KeySize]byte
 	chainKey, tau, key = KDF3(chainKey[:], handshake.presharedKey[:])
-	hash = addToHash(hash, tau[:])
+	hash = mixHash(hash, tau[:])
 
 	// authenticate
 
@@ -330,7 +336,7 @@ func (device *Device) ConsumeMessageResponse(msg *MessageResponse) *Peer {
 	if err != nil {
 		return nil
 	}
-	hash = addToHash(hash, msg.Empty[:])
+	hash = mixHash(hash, msg.Empty[:])
 
 	// update handshake state
 
@@ -368,7 +374,11 @@ func (peer *Peer) NewKeyPair() *KeyPair {
 	keyPair.sendNonce = 0
 	keyPair.recvNonce = 0
 
-	peer.handshake.state = HandshakeReset
+	// zero handshake
+
+	handshake.chainKey = [blake2s.Size]byte{}
+	handshake.localEphemeral = NoisePrivateKey{}
+	peer.handshake.state = HandshakeZeroed
 
 	return &keyPair
 }
diff --git a/src/noise_test.go b/src/noise_test.go
index ddabf8e..8450c1c 100644
--- a/src/noise_test.go
+++ b/src/noise_test.go
@@ -67,13 +67,13 @@ func TestNoiseHandshake(t *testing.T) {
 
 	t.Log("exchange initiation message")
 
-	msg1, err := dev1.CreateMessageInitial(peer2)
+	msg1, err := dev1.CreateMessageInitiation(peer2)
 	assertNil(t, err)
 
 	packet := make([]byte, 0, 256)
 	writer := bytes.NewBuffer(packet)
 	err = binary.Write(writer, binary.LittleEndian, msg1)
-	peer := dev2.ConsumeMessageInitial(msg1)
+	peer := dev2.ConsumeMessageInitiation(msg1)
 	if peer == nil {
 		t.Fatal("handshake failed at initiation message")
 	}
diff --git a/src/peer.go b/src/peer.go
index f6eb555..42b9e8d 100644
--- a/src/peer.go
+++ b/src/peer.go
@@ -1,39 +1,64 @@
 package main
 
 import (
+	"errors"
+	"golang.org/x/crypto/blake2s"
 	"net"
 	"sync"
 	"time"
 )
 
+const (
+	OutboundQueueSize = 64
+)
+
 type Peer struct {
 	mutex                       sync.RWMutex
 	endpointIP                  net.IP        //
 	endpointPort                uint16        //
 	persistentKeepaliveInterval time.Duration // 0 = disabled
+	keyPairs                    KeyPairs
 	handshake                   Handshake
 	device                      *Device
+	macKey                      [blake2s.Size]byte // Hash(Label-Mac1 || publicKey)
+	cookie                      []byte             // cookie
+	cookieExpire                time.Time
+	queueInbound                chan []byte
+	queueOutbound               chan *OutboundWorkQueueElement
+	queueOutboundRouting        chan []byte
 }
 
 func (device *Device) NewPeer(pk NoisePublicKey) *Peer {
 	var peer Peer
 
+	// create peer
+
+	peer.mutex.Lock()
+	peer.device = device
+	peer.queueOutbound = make(chan *OutboundWorkQueueElement, OutboundQueueSize)
+
 	// map public key
 
 	device.mutex.Lock()
+	_, ok := device.peers[pk]
+	if ok {
+		panic(errors.New("bug: adding existing peer"))
+	}
 	device.peers[pk] = &peer
 	device.mutex.Unlock()
 
-	// precompute
+	// precompute DH
 
-	peer.mutex.Lock()
-	peer.device = device
-	func(h *Handshake) {
-		h.mutex.Lock()
-		h.remoteStatic = pk
-		h.precomputedStaticStatic = device.privateKey.sharedSecret(h.remoteStatic)
-		h.mutex.Unlock()
-	}(&peer.handshake)
+	handshake := &peer.handshake
+	handshake.mutex.Lock()
+	handshake.remoteStatic = pk
+	handshake.precomputedStaticStatic = device.privateKey.sharedSecret(handshake.remoteStatic)
+
+	// compute mac key
+
+	peer.macKey = blake2s.Sum256(append([]byte(WGLabelMAC1[:]), handshake.remoteStatic[:]...))
+
+	handshake.mutex.Unlock()
 	peer.mutex.Unlock()
 
 	return &peer
diff --git a/src/routing.go b/src/routing.go
index 553df11..4189c25 100644
--- a/src/routing.go
+++ b/src/routing.go
@@ -2,7 +2,6 @@ package main
 
 import (
 	"errors"
-	"fmt"
 	"net"
 	"sync"
 )
@@ -52,25 +51,3 @@ func (table *RoutingTable) LookupIPv6(address []byte) *Peer {
 	defer table.mutex.RUnlock()
 	return table.IPv6.Lookup(address)
 }
-
-func OutgoingRoutingWorker(device *Device, queue chan []byte) {
-	for {
-		packet := <-queue
-		switch packet[0] >> 4 {
-
-		case IPv4version:
-			dst := packet[IPv4offsetDst : IPv4offsetDst+net.IPv4len]
-			peer := device.routingTable.LookupIPv4(dst)
-			fmt.Println("IPv4", peer)
-
-		case IPv6version:
-			dst := packet[IPv6offsetDst : IPv6offsetDst+net.IPv6len]
-			peer := device.routingTable.LookupIPv6(dst)
-			fmt.Println("IPv6", peer)
-
-		default:
-			// todo: log
-			fmt.Println("Unknown IP version")
-		}
-	}
-}
diff --git a/src/send.go b/src/send.go
new file mode 100644
index 0000000..9790320
--- /dev/null
+++ b/src/send.go
@@ -0,0 +1,154 @@
+package main
+
+import (
+	"net"
+	"sync"
+	"sync/atomic"
+)
+
+/* Handles outbound flow
+ *
+ * 1. TUN queue
+ * 2. Routing
+ * 3. Per peer queuing
+ * 4. (work queuing)
+ *
+ */
+
+type OutboundWorkQueueElement struct {
+	wg      sync.WaitGroup
+	packet  []byte
+	nonce   uint64
+	keyPair *KeyPair
+}
+
+func (device *Device) SendPacket(packet []byte) {
+
+	// lookup peer
+
+	var peer *Peer
+	switch packet[0] >> 4 {
+	case IPv4version:
+		dst := packet[IPv4offsetDst : IPv4offsetDst+net.IPv4len]
+		peer = device.routingTable.LookupIPv4(dst)
+
+	case IPv6version:
+		dst := packet[IPv6offsetDst : IPv6offsetDst+net.IPv6len]
+		peer = device.routingTable.LookupIPv6(dst)
+
+	default:
+		device.logger.Println("unknown IP version")
+		return
+	}
+
+	if peer == nil {
+		return
+	}
+
+	// insert into peer queue
+
+	for {
+		select {
+		case peer.queueOutboundRouting <- packet:
+		default:
+			select {
+			case <-peer.queueOutboundRouting:
+			default:
+			}
+			continue
+		}
+		break
+	}
+}
+
+/* Go routine
+ *
+ *
+ * 1. waits for handshake.
+ * 2. assigns key pair & nonce
+ * 3. inserts to working queue
+ *
+ * TODO: avoid dynamic allocation of work queue elements
+ */
+func (peer *Peer) ConsumeOutboundPackets() {
+	for {
+		// wait for key pair
+		keyPair := func() *KeyPair {
+			peer.keyPairs.mutex.RLock()
+			defer peer.keyPairs.mutex.RUnlock()
+			return peer.keyPairs.current
+		}()
+		if keyPair == nil {
+			if len(peer.queueOutboundRouting) > 0 {
+				// TODO: start handshake
+				<-peer.keyPairs.newKeyPair
+			}
+			continue
+		}
+
+		// assign packets key pair
+		for {
+			select {
+			case <-peer.keyPairs.newKeyPair:
+			default:
+			case <-peer.keyPairs.newKeyPair:
+			case packet := <-peer.queueOutboundRouting:
+
+				// create new work element
+
+				work := new(OutboundWorkQueueElement)
+				work.wg.Add(1)
+				work.keyPair = keyPair
+				work.packet = packet
+				work.nonce = atomic.AddUint64(&keyPair.sendNonce, 1) - 1
+
+				peer.queueOutbound <- work
+
+				// drop packets until there is room
+
+				for {
+					select {
+					case peer.device.queueWorkOutbound <- work:
+						break
+					default:
+						drop := <-peer.device.queueWorkOutbound
+						drop.packet = nil
+						drop.wg.Done()
+					}
+				}
+			}
+		}
+	}
+}
+
+func (peer *Peer) RoutineSequential() {
+	for work := range peer.queueOutbound {
+		work.wg.Wait()
+		if work.packet == nil {
+			continue
+		}
+	}
+}
+
+func (device *Device) EncryptionWorker() {
+	for {
+		work := <-device.queueWorkOutbound
+
+		func() {
+			defer work.wg.Done()
+
+			// pad packet
+			padding := device.mtu - len(work.packet)
+			if padding < 0 {
+				work.packet = nil
+				return
+			}
+			for n := 0; n < padding; n += 1 {
+				work.packet = append(work.packet, 0) // TODO: gotta be a faster way
+			}
+
+			//
+
+		}()
+	}
+}