Work on UAPI

Cross-platform API (get operation)
Handshake initiation creation process
Outbound packet flow
Fixes from code-review

src/handshake.go

@@ -0,0 +1,172 @@
+package main
+
+import (
+	"bytes"
+	"encoding/binary"
+	"net"
+	"sync/atomic"
+	"time"
+)
+
+/* Sends a keep-alive if no packets queued for peer
+ *
+ * Used by initiator of handshake and with active keep-alive
+ */
+func (peer *Peer) SendKeepAlive() bool {
+	if len(peer.queue.nonce) == 0 {
+		select {
+		case peer.queue.nonce <- []byte{}:
+			return true
+		default:
+			return false
+		}
+	}
+	return true
+}
+
+func (peer *Peer) RoutineHandshakeInitiator() {
+	var ongoing bool
+	var begun time.Time
+	var attempts uint
+	var timeout time.Timer
+
+	device := peer.device
+	work := new(QueueOutboundElement)
+	buffer := make([]byte, 0, 1024)
+
+	queueHandshakeInitiation := func() error {
+		work.mutex.Lock()
+		defer work.mutex.Unlock()
+
+		// create initiation
+
+		msg, err := device.CreateMessageInitiation(peer)
+		if err != nil {
+			return err
+		}
+
+		// create "work" element
+
+		writer := bytes.NewBuffer(buffer[:0])
+		binary.Write(writer, binary.LittleEndian, &msg)
+		work.packet = writer.Bytes()
+		peer.mac.AddMacs(work.packet)
+		peer.InsertOutbound(work)
+		return nil
+	}
+
+	for {
+		select {
+		case <-peer.signal.stopInitiator:
+			return
+
+		case <-peer.signal.newHandshake:
+			if ongoing {
+				continue
+			}
+
+			// create handshake
+
+			err := queueHandshakeInitiation()
+			if err != nil {
+				device.log.Error.Println("Failed to create initiation message:", err)
+			}
+
+			// log when we began
+
+			begun = time.Now()
+			ongoing = true
+			attempts = 0
+			timeout.Reset(RekeyTimeout)
+
+		case <-peer.timer.sendKeepalive.C:
+
+			// active keep-alives
+
+			peer.SendKeepAlive()
+
+		case <-peer.timer.handshakeTimeout.C:
+
+			// check if we can stop trying
+
+			if time.Now().Sub(begun) > MaxHandshakeAttempTime {
+				peer.signal.flushNonceQueue <- true
+				peer.timer.sendKeepalive.Stop()
+				ongoing = false
+				continue
+			}
+
+			// otherwise, try again (exponental backoff)
+
+			attempts += 1
+			err := queueHandshakeInitiation()
+			if err != nil {
+				device.log.Error.Println("Failed to create initiation message:", err)
+			}
+			peer.timer.handshakeTimeout.Reset((1 << attempts) * RekeyTimeout)
+		}
+	}
+}
+
+/* Handles packets related to handshake
+ *
+ *
+ */
+func (device *Device) HandshakeWorker(queue chan struct {
+	msg     []byte
+	msgType uint32
+	addr    *net.UDPAddr
+}) {
+	for {
+		elem := <-queue
+
+		switch elem.msgType {
+		case MessageInitiationType:
+			if len(elem.msg) != MessageInitiationSize {
+				continue
+			}
+
+			// check for cookie
+
+			var msg MessageInitiation
+
+			binary.Read(nil, binary.LittleEndian, &msg)
+
+		case MessageResponseType:
+			if len(elem.msg) != MessageResponseSize {
+				continue
+			}
+
+			// check for cookie
+
+		case MessageCookieReplyType:
+
+		case MessageTransportType:
+		}
+
+	}
+}
+
+func (device *Device) KeepKeyFresh(peer *Peer) {
+
+	send := func() bool {
+		peer.keyPairs.mutex.RLock()
+		defer peer.keyPairs.mutex.RUnlock()
+
+		kp := peer.keyPairs.current
+		if kp == nil {
+			return false
+		}
+
+		nonce := atomic.LoadUint64(&kp.sendNonce)
+		if nonce > RekeyAfterMessage {
+			return true
+		}
+
+		return kp.isInitiator && time.Now().Sub(kp.created) > RekeyAfterTime
+	}()
+
+	if send {
+
+	}
+}