Forward a packet with sleeve if the source or dest peer lacks a short ID

router/fastdp.go

@@ -754,6 +754,10 @@ func (fwd *fastDatapathForwarder) handleHeartbeatAck() {
 }
 
 func (fwd *fastDatapathForwarder) Forward(key ForwardPacketKey) FlowOp {
+	if !key.SrcPeer.HasShortID || !key.DstPeer.HasShortID {
+		return nil
+	}
+
 	fwd.lock.RLock()
 	defer fwd.lock.RUnlock()
 

router/overlay.go

@@ -68,7 +68,8 @@ type OverlayCrypto struct {
 type OverlayForwarder interface {
 	// Forward a packet across the connection.  May be called as
 	// soon as the forwarder is created, in particular before
-	// Confirm().
+	// Confirm().  The return value nil means the key could not be
+	// handled by this forwarder.
 	Forward(ForwardPacketKey) FlowOp
 
 	// Confirm that the connection is really wanted, and so the

router/overlay_switch.go

@@ -124,8 +124,8 @@ type overlaySwitchForwarder struct {
 
 	lock sync.Mutex
 
-	// the forwarder to send on
-	best OverlayForwarder
+	// the index of the forwarder to send on
+	best int
 
 	// the subsidiary forwarders
 	forwarders []subForwarder
@@ -183,6 +183,7 @@ func (osw *OverlaySwitch) MakeForwarder(
 	fwd := &overlaySwitchForwarder{
 		remotePeer: params.RemotePeer,
 
+		best:       -1,
 		forwarders: make([]subForwarder, len(overlays)),
 		stopChan:   stopChan,
 
@@ -285,9 +286,6 @@ func (fwd *overlaySwitchForwarder) established(index int) {
 
 	fwd.forwarders[index].established = true
 
-	// less preferred forwarders are no longer needed
-	fwd.stopFrom(index + 1)
-
 	if !fwd.alreadyEstablished {
 		fwd.alreadyEstablished = true
 		close(fwd.establishedChan)
@@ -323,7 +321,8 @@ func (fwd *overlaySwitchForwarder) stopFrom(index int) {
 func (fwd *overlaySwitchForwarder) chooseBest() {
 	// the most preferred established forwarder is the best
 	// otherwise, the most preferred working forwarder is the best
-	var bestEstablished, bestWorking *subForwarder
+	bestEstablished := -1
+	bestWorking := -1
 
 	for i := range fwd.forwarders {
 		subFwd := &fwd.forwarders[i]
@@ -331,18 +330,18 @@ func (fwd *overlaySwitchForwarder) chooseBest() {
 			continue
 		}
 
-		if bestWorking == nil {
-			bestWorking = subFwd
+		if bestWorking < 0 {
+			bestWorking = i
 		}
 
-		if bestEstablished == nil && subFwd.established {
-			bestEstablished = subFwd
+		if bestEstablished < 0 && subFwd.established {
+			bestEstablished = i
 		}
 	}
 
 	best := bestEstablished
-	if best == nil {
-		if bestWorking == nil {
+	if best < 0 {
+		if bestWorking < 0 {
 			select {
 			case fwd.errorChan <- fmt.Errorf("no working forwarders to %s", fwd.remotePeer):
 			default:
@@ -354,9 +353,10 @@ func (fwd *overlaySwitchForwarder) chooseBest() {
 		best = bestWorking
 	}
 
-	if fwd.best != best.fwd {
-		fwd.best = best.fwd
-		log.Info(fwd.logPrefix(), "using ", best.overlayName)
+	if fwd.best != best {
+		fwd.best = best
+		log.Info(fwd.logPrefix(),
+			"using ", fwd.forwarders[best].overlayName)
 	}
 }
 
@@ -378,14 +378,23 @@ func (fwd *overlaySwitchForwarder) Confirm() {
 
 func (fwd *overlaySwitchForwarder) Forward(pk ForwardPacketKey) FlowOp {
 	fwd.lock.Lock()
-	best := fwd.best
-	fwd.lock.Unlock()
 
-	if best == nil {
-		return nil
+	if fwd.best >= 0 {
+		for i := fwd.best; i < len(fwd.forwarders); i++ {
+			best := fwd.forwarders[i].fwd
+			if best != nil {
+				fwd.lock.Unlock()
+				if op := best.Forward(pk); op != nil {
+					return op
+				}
+				fwd.lock.Lock()
+			}
+		}
 	}
 
-	return best.Forward(pk)
+	fwd.lock.Unlock()
+
+	return DiscardingFlowOp{}
 }
 
 func (fwd *overlaySwitchForwarder) EstablishedChannel() <-chan struct{} {
@@ -412,13 +421,17 @@ func (fwd *overlaySwitchForwarder) ControlMessage(tag byte, msg []byte) {
 }
 
 func (fwd *overlaySwitchForwarder) DisplayName() string {
+	var best OverlayForwarder
+
 	fwd.lock.Lock()
-	best := fwd.best
+	if fwd.best > 0 {
+		best = fwd.forwarders[fwd.best].fwd
+	}
 	fwd.lock.Unlock()
 
-	if best == nil {
-		return "none"
+	if best != nil {
+		return best.DisplayName()
 	}
 
-	return best.DisplayName()
+	return "none"
 }