From eb75ff430d1f78e129bbfe49d612f241ca418df4 Mon Sep 17 00:00:00 2001
From: Mathias Hall-Andersen <mathias@hall-andersen.dk>
Date: Mon, 26 Jun 2017 22:07:29 +0200
Subject: Begin implementation of outbound work queue

---
 src/send.go | 124 ++++++++++++++++++++++++++++++++++++++----------------------
 1 file changed, 78 insertions(+), 46 deletions(-)

(limited to 'src/send.go')

diff --git a/src/send.go b/src/send.go
index 9790320..da5905d 100644
--- a/src/send.go
+++ b/src/send.go
@@ -1,9 +1,11 @@
 package main
 
 import (
+	"encoding/binary"
+	"golang.org/x/crypto/chacha20poly1305"
 	"net"
 	"sync"
-	"sync/atomic"
+	"time"
 )
 
 /* Handles outbound flow
@@ -70,85 +72,115 @@ func (device *Device) SendPacket(packet []byte) {
  *
  * TODO: avoid dynamic allocation of work queue elements
  */
-func (peer *Peer) ConsumeOutboundPackets() {
+func (peer *Peer) RoutineOutboundNonceWorker() {
+	var packet []byte
+	var keyPair *KeyPair
+	var flushTimer time.Timer
+
 	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
+
+		// wait for packet
+
+		if packet == nil {
+			packet = <-peer.queueOutboundRouting
 		}
 
-		// assign packets key pair
-		for {
+		// wait for key pair
+
+		for keyPair == nil {
+			flushTimer.Reset(time.Second * 10)
+			// TODO: Handshake or NOP
 			select {
 			case <-peer.keyPairs.newKeyPair:
-			default:
-			case <-peer.keyPairs.newKeyPair:
-			case packet := <-peer.queueOutboundRouting:
+				keyPair = peer.keyPairs.Current()
+				continue
+			case <-flushTimer.C:
+				size := len(peer.queueOutboundRouting)
+				for i := 0; i < size; i += 1 {
+					<-peer.queueOutboundRouting
+				}
+				packet = nil
+			}
+			break
+		}
+
+		// process current packet
+
+		if packet != nil {
 
-				// create new work element
+			// create work element
 
-				work := new(OutboundWorkQueueElement)
-				work.wg.Add(1)
-				work.keyPair = keyPair
-				work.packet = packet
-				work.nonce = atomic.AddUint64(&keyPair.sendNonce, 1) - 1
+			work := new(OutboundWorkQueueElement)
+			work.wg.Add(1)
+			work.keyPair = keyPair
+			work.packet = packet
+			work.nonce = keyPair.sendNonce
 
-				peer.queueOutbound <- work
+			packet = nil
+			peer.queueOutbound <- work
+			keyPair.sendNonce += 1
 
-				// drop packets until there is room
+			// drop packets until there is space
 
+			func() {
 				for {
 					select {
 					case peer.device.queueWorkOutbound <- work:
-						break
+						return
 					default:
 						drop := <-peer.device.queueWorkOutbound
 						drop.packet = nil
 						drop.wg.Done()
 					}
 				}
-			}
+			}()
 		}
 	}
 }
 
+/* Go routine
+ *
+ * sequentially reads packets from queue and sends to endpoint
+ *
+ */
 func (peer *Peer) RoutineSequential() {
 	for work := range peer.queueOutbound {
 		work.wg.Wait()
+
+		// check if dropped ("ghost packet")
+
 		if work.packet == nil {
 			continue
 		}
+
+		//
+
 	}
 }
 
-func (device *Device) EncryptionWorker() {
-	for {
-		work := <-device.queueWorkOutbound
-
-		func() {
-			defer work.wg.Done()
+func (device *Device) RoutineEncryptionWorker() {
+	var nonce [chacha20poly1305.NonceSize]byte
+	for work := range device.queueWorkOutbound {
+		// pad packet
 
-			// 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
-			}
+		padding := device.mtu - len(work.packet)
+		if padding < 0 {
+			work.packet = nil
+			work.wg.Done()
+		}
+		for n := 0; n < padding; n += 1 {
+			work.packet = append(work.packet, 0)
+		}
 
-			//
+		// encrypt
 
-		}()
+		binary.LittleEndian.PutUint64(nonce[4:], work.nonce)
+		work.packet = work.keyPair.send.Seal(
+			work.packet[:0],
+			nonce[:],
+			work.packet,
+			nil,
+		)
+		work.wg.Done()
 	}
 }
-- 
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