Add funcs to request free route id from visor

pkg/setup/node.go

@@ -317,6 +317,28 @@ func (sn *Node) closeLoop(on cipher.PubKey, ld routing.LoopData) error {
 	return nil
 }
 
+func (sn *Node) requestRouteID(ctx context.Context, pubKey cipher.PubKey) (uint32, error) {
+	sn.Logger.Debugf("dialing to %s to request route ID\n", pubKey)
+	tr, err := sn.messenger.Dial(ctx, pubKey)
+	if err != nil {
+		return 0, fmt.Errorf("transport: %s", err)
+	}
+	defer func() {
+		if err := tr.Close(); err != nil {
+			sn.Logger.Warnf("Failed to close transport: %s", err)
+		}
+	}()
+
+	proto := NewSetupProtocol(tr)
+	routeID, err := RequestRouteID(proto)
+	if err != nil {
+		return 0, err
+	}
+
+	sn.Logger.Infof("Received route ID %d from %s", routeID, pubKey)
+	return routeID, nil
+}
+
 func (sn *Node) setupRule(ctx context.Context, pubKey cipher.PubKey,
 	rule routing.Rule) (routeID routing.RouteID, err error) {
 	sn.Logger.Debugf("dialing to %s to setup rule: %v\n", pubKey, rule)

pkg/setup/protocol.go

@@ -49,6 +49,8 @@ const (
 	PacketCloseLoop
 	// PacketLoopClosed represents LoopClosed foundation packet.
 	PacketLoopClosed
+	// PacketRequestRouteID represents RequestRouteID foundation packet.
+	PacketRequestRouteID
 
 	// RespFailure represents failure response for a foundation packet.
 	RespFailure = 0xfe
@@ -99,6 +101,21 @@ func (p *Protocol) WritePacket(t PacketType, body interface{}) error {
 	return err
 }
 
+// RequestRouteID sends RequestRouteID request.
+func RequestRouteID(p *Protocol) (uint32, error) {
+	if err := p.WritePacket(PacketRequestRouteID, nil); err != nil {
+		return 0, err
+	}
+	var res []uint32
+	if err := readAndDecodePacket(p, &res); err != nil {
+		return 0, err
+	}
+	if len(res) == 0 {
+		return 0, errors.New("empty response")
+	}
+	return res[0], nil
+}
+
 // AddRule sends AddRule setup request.
 func AddRule(p *Protocol, rule routing.Rule) (routeID routing.RouteID, err error) {
 	if err = p.WritePacket(PacketAddRules, []routing.Rule{rule}); err != nil {