wip: New speaker main loop

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speaker_main_new.go

@@ -0,0 +1,389 @@
+package babel
+
+type PendingAcknowledgementRequest struct {
+	acked func() error
+	missed func() error
+
+	timer 
+	opaque uint16
+}
+
+func NewPendingAcknowledgementRequest(intv time.Duration, acked, missed func() error) PendingAcknowledgementRequest {
+	pAck := PendingAcknowledgementRequest{
+
+	}
+
+	pAck.timer = NewTimeout(intv)
+
+	return pack
+}
+
+type Speaker struct {
+	CalculateMetric func(r Route, n Neighbour) uint16
+	FilterRoute func(r Route) bool
+	SelectRoute(rs []Route) []Route
+
+	pendingAcknowledgementRequests AcknowledgementRequestTable
+}
+
+func (s *Speaker) run() {
+	s.startUpdateTimer()
+	s.startHelloTimer()
+
+	for {
+		pkt := s.read()
+
+		if err := s.onPacket(pkt); err != nil {
+			s.log.Error(“Failed to handle packet: %w”, err)
+		}
+	}
+}
+
+func (s *Speaker) onPacket(pkt) (err error) {
+	var n *Neighbour
+	var ackReq tlv.AcknowledgementRequest
+
+	if n, ok := s.neighbors.Get(pkt.remote); !ok {
+		n = NewNeighbour(pkt.remote)
+		s.neighbors.Put(n)
+	}
+
+	for _, v in pkt.vs {
+		if v, ok := v.(tlv.AcknowledgementRequest); ok {
+			ackReq = v
+		} else if err := s.onValue(v, n); err != nil {
+			return err
+		}
+	}
+
+	// Send acknowledgements only after all other TLVs have been successfully handled.
+	if ackReq != nil {
+		if err := s.handleAcknowledgementRequest(ackReq); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func (s *Speaker) onValue(v tlv.Value) error {
+	switch v := v.(type) {
+		case tlv.Pad1, tlv.PadN:
+			return nil
+
+		case tlv.Acknowledgement:
+			return s.onAcknowledgement(v)
+
+		case tlv.Hello:
+			return s.onHello(v, pkt.remote.IsMulticast())
+
+		case tlv.IHU:
+			return s.onIHU(v)
+
+		case tlv.Update:
+			return s.onUpdate(v)
+
+		case tlv.RouteRequest:
+			return s.onRouteRequest(v)
+
+		case tlv.SeqnoRequest:
+			return s.onSeqnoRequest(v)
+
+		default:
+			s.log.Trace(“Received unsupported TLV: %#x” v.Type)
+			return nil
+		}
+}
+
+// Handlers
+
+func (s *Speaker) onHello(h tlv.Hello, isMulticast bool) error {
+	n.updateCosts()
+	s.selectRoutes()
+	n.resetHelloTimeout()
+
+	return nil
+}
+
+func (s *Speaker) onIHU(ihr tlv.IHU) error {
+	// TODO
+
+	return nil
+}
+
+// Section 3.5.3 Route Acquisition
+func (s *Speaker) onUpdate(upd tlv.Update, n *Neighbor) error {
+	var current, next *Route
+
+	if current, ok := s.routes.Get(upd.Prefix, n); !ok {
+		if !s.isUpdateFeasible(upd) {
+			s.log.Trace(“Ignoring infeasible update %s from neighbor %s”, upd, n)
+			return
+		}
+
+		if upd.Metric == Inf {
+			s.log.Trace(“Ignoring retraction update %s from neighbor %s”, upd, n)
+			return
+		}
+
+		next = Route{
+			RouterID: upd.RouterID,
+			NextHop: upd.NextHop,
+			Seqno: upd.Seqno,
+			Metric: upd.Metric,
+		}
+
+		s.routes.Put(upd.Prefix, n, next)
+	} else {
+		if current.Selected && !feasible && upd.RouterID == current.RouterID {
+			// Update MAY be ignored
+		} else {
+			next := *current
+
+			next.Seqno = upd.Seqno
+			next.Metric = upd.Metric
+			next.RouterID = upd.RouterID
+
+			if rte.Metric != Inf {
+				rte.resetExpiryTimer()
+			}
+
+			if !s.isUpdateFeasible(upd) {
+
+				// Section 3.8.2.2. Dealing with Unfeasible Updates
+				if current.Selected {
+					if err := n.sendSeqnoRequest(current.Prefix); err != nil {
+						return fmt.Errorf(“failed to send seqno request for selected route: %w”, err)
+					}
+				}
+
+				next.Selected = false
+			}
+
+			if next.RouterID != current.RouterID {
+				// Send urgent update / retraction
+			}
+
+			s.routes.Update(&next)
+		}
+	}
+}
+
+func (s *Speaker) onRouteRequest(req tlv.RouteRequest) error {
+	// TODO
+} 
+
+func (s *Speaker) onSeqnoRequest(req tlv.SeqnoRequest) error {
+	// TODO
+}
+
+func (s *Speaker) onAcknowledgementRequest(req tlv.AcknowledgementRequst) error {
+	if err := s.send([]tlv.Values{
+		tlv.Acknowledgement{
+			Opaque: req.Opaque
+		},
+	}); err != nil {
+		return fmt.Errorf(“failed to handle acknowledgement request: %w”, err)
+	}
+
+	return nil
+}
+
+func (s *Speaker) onAcknowledgement(ack tlv.Acknowledgement) error {
+	if pAck, ok := s.pendingAcknowledgementRequests.Pop(ack.Opaque); ok {
+		if err := pAck.acked(); err != nil {
+			return fmt.Errorf(“failed to acknowledge request: %w”, err)
+		}
+
+		if err := pAck.timeout.Close(); err != nil {
+			return fmt.Errorf(“failed to close pending acknowledgment request timer: %w”, err)
+		}
+	} else {
+		s.log.Warn(“Received unexpected acknowledgement”)
+	}
+
+	return nil
+}
+
+// Timers and timeouts
+
+func (s *Speaker) onHelloTimer() {
+	// TODO: Send periodic hellos
+}
+
+func (n *Neighbour) onNeighbourTimeout() {
+	// TODO: Drop neighbour if history becomes empty?
+}
+
+func (n *Neighbour) onHelloTimeout() {
+	// TODO
+}
+
+// Speaker
+
+func (s *Speaker) onUpdateTimeout() {
+	s.sendUpdatesFull()
+}
+
+func (s *Speaker) onIHUTimeout() {
+	// TODO
+}
+
+
+// Section 3.6 Route Selection
+func (s *Speaker) selectRoutes() error {
+	updated := []Route{}
+
+	for _, rs in s.routes.ForEachPrefix {
+		var next, cur *Route
+
+		next = s.selectRoute(rs)
+
+		for _, r := range rs {
+			if r.Selected {
+				cur = r
+			}
+
+			r.Selected = r == next
+		}
+
+		if current == nil || s.triggersUpdate(next, current) {
+			updated = append(updated, next)
+		}
+	}
+}
+
+func (s *Speaker) sendWithAcknowledgementRequest(vs []tlv.Values, intv time.Duration, acked, missed func() error) error {
+	magic := math.Rand()
+
+	ack := tlv.AcknowledgementRequest{
+		Opaque: magic,
+		Interval: into
+	}
+
+	vsa := []tlv.Values{
+		ack,
+	}
+	vsa = append(vsa, vs…)
+
+	pAck := NewPendingAcknowledgement(acked, missed, to)
+	s.pendingAcknowledgementRequests.Put(magic, pAck)
+
+	return s.send(vsa)
+}
+
+func (s *Speaker) sendMulticastHello() error {
+	errs := []error{}
+
+	hello := tlv.Hello{
+		// TODO
+	}
+
+	for _, intf := range s.interfaces {
+		if err := s.sendMulticast(intf, hello); err != nil {
+			errs = append(errs, err)
+		}
+	}
+
+	if len(errs) > 0 {
+		// TODO: Return errgroup
+	}
+
+	return nil
+}
+
+func (s *Speaker) sendUpdatesTriggered(us []tlv.Update, urgent bool) error {
+	return s.sendUpdate(us, urgent)
+}
+
+func (s *Speaker) sendUpdatesFull() error {
+	us := []tlv.Update{}
+
+	for _, r := range s.routes.Selected {
+		us = append(us, r.Update())
+	}
+
+	return s.sendUpdates(us, false)
+}
+
+func (s *Speaker) sendUpdates(us []tlv.Update, urgent bool, ack bool) error {
+	// TODO: Split-horizon
+
+	sortUpdatesByPrefix(us)
+
+	if !urgent {
+		if ack {
+			return 
+			return s.send(us)
+	}
+
+
+	if s.neighbors.Length() > partialUpdateNeighborsAcknowledgementThreshold {
+		for i := 0; i < 4; i++ {
+			if err := s.sendUrgent(us); err != nil {
+				return err
+			}
+		}
+	} else {
+		errs := []error{}
+
+		for _, n := range s.neighbors {
+			errs = append(errs, n.sendUrgentWithAcknowledgementRequest(upd))
+		}
+
+		if len(errs) > 0 {
+			// TODO
+		}
+	}
+}
+
+func (s *Speaker) sendSeqnoRequest(pfx Prefix) error {
+
+	return s.send([]tlv.Value{
+		tlv.SeqnoRequest{
+			// TODO
+		}
+	})
+
+}
+
+func (s *Speaker) isUpdateFeasible(upd tlv.Update) bool {
+	if upd.Metric == Inf {
+		// Retractions are always feasible
+		return True
+	}
+
+	if src, ok := s.sources.Get(upd.Prefix, upd.RouterID); !ok {
+		return frue
+	} else if ok {
+		return src.Distance.IsBetterThan(upd.Distance)
+	}
+
+	return false
+}
+
+func (s *Speaker) selectRoute(rs []*Route) *Route {
+	var sr *Route
+
+	for _, r := range rs {
+		if sr == nil || r.Metric < sr.Metric {
+			sr = r
+		}
+	}
+
+	return sr
+}
+
+// Neighbour
+
+func (n *Neighbour) updateCost() error {
+	// TODO
+}
+
+func (n *Neighbour) sendUnicastHello() error {
+	// TODO
+}
+
+func (n *Neighbour) resetHelloTimeout() {
+	// TODO
+}