func (o *OnDemandProbeServer) getProbe(n *graph.Node, capture *api.Capture) (*probes.FlowProbe, error) {
	capType := ""
	if capture.Type != "" {
		types := common.CaptureTypes[n.Metadata()["Type"].(string)].Allowed
		for _, t := range types {
			if t == capture.Type {
				capType = t
				break
			}
		}
		if capType == "" {
			return nil, fmt.Errorf("Capture type %v not allowed on this node: %v", capture, n)
		}
	} else {
		// no capture type defined for this type of node, ex: ovsport
		c, ok := common.CaptureTypes[n.Metadata()["Type"].(string)]
		if !ok {
			return nil, nil
		}
		capType = c.Default
	}
	probe := o.Probes.GetProbe(capType)
	if probe == nil {
		return nil, fmt.Errorf("Unable to find probe for this capture type: %v", capType)
	}

	fprobe := probe.(probes.FlowProbe)
	return &fprobe, nil
}

func (o *OnDemandProbeListener) registerProbe(n *graph.Node, capture *api.Capture) bool {
	o.Lock()
	defer o.Unlock()

	if _, ok := o.activeProbes[n.ID]; ok {
		logging.GetLogger().Debugf("A probe already exists for %s", n.ID)
		return false
	}

	if _, ok := n.Metadata()["Type"]; !ok {
		logging.GetLogger().Infof("Do not register flow probe, type not supported %v", n)
		return false
	}

	fprobe := o.getProbe(n, capture)
	if fprobe == nil {
		logging.GetLogger().Errorf("Failed to register flow probe, unknown type %v", n)
		return false
	}

	ft := o.fta.Alloc(fprobe.AsyncFlowPipeline)
	if err := fprobe.RegisterProbe(n, capture, ft); err != nil {
		logging.GetLogger().Debugf("Failed to register flow probe: %s", err.Error())
		o.fta.Release(ft)
		return false
	}

	o.activeProbes[n.ID] = ft
	o.captures[n.ID] = capture

	logging.GetLogger().Debugf("New active probe on: %v", n)
	return true
}

func (o *OvsSFlowProbesHandler) RegisterProbe(n *graph.Node, capture *api.Capture, ft *flow.Table) error {
	if isOvsBridge(n) {
		err := o.RegisterProbeOnBridge(n.Metadata()["UUID"].(string), string(n.ID), ft)
		if err != nil {
			return err
		}
	}
	return nil
}

func (o *OvsSFlowProbesHandler) UnregisterProbe(n *graph.Node) error {
	if isOvsBridge(n) {
		err := o.unregisterProbe(n.Metadata()["UUID"].(string))
		if err != nil {
			return err
		}
	}
	return nil
}

func (mapper *OpenContrailMapper) OnNodeDeleted(n *graph.Node) {
	name, ok := n.Metadata()["Name"]
	if !ok {
		return
	}
	if n.ID == mapper.vHost.ID {
		logging.GetLogger().Debugf("Removed %s", name.(string))
		mapper.vHost = nil
	}
}

func (o *OnDemandProbeClient) unregisterProbe(node *graph.Node) bool {
	msg := shttp.NewWSMessage(ondemand.Namespace, "CaptureStop", ondemand.CaptureQuery{NodeID: string(node.ID)})

	if !o.wsServer.SendWSMessageTo(msg, node.Host()) {
		logging.GetLogger().Errorf("Unable to send message to agent: %s", node.Host())
		return false
	}

	return true
}

func (o *OnDemandProbeClient) onNodeEvent(n *graph.Node) {
	if state, ok := n.Metadata()["State/FlowCapture"]; ok && state.(string) == "ON" {
		return
	}

	for _, capture := range o.captures {
		if o.matchGremlinExpr(n, capture.GremlinQuery) {
			go o.registerProbe(n, capture)
		}
	}
}

func (o *OnDemandProbeServer) OnNodeDeleted(n *graph.Node) {
	if state, ok := n.Metadata()["State/FlowCapture"]; !ok || state.(string) == "OFF" {
		return
	}

	if o.unregisterProbe(n) {
		metadata := n.Metadata()
		metadata["State/FlowCapture"] = "OFF"
		delete(metadata, "CaptureID")
		o.Graph.SetMetadata(n, metadata)
	}
}

func (o *OnDemandProbeListener) OnNodeDeleted(n *graph.Node) {
	if !o.isActive(n) {
		return
	}

	if o.unregisterProbe(n) {
		metadata := n.Metadata()
		metadata["State/FlowCapture"] = "OFF"
		delete(metadata, "CaptureID")
		o.Graph.SetMetadata(n, metadata)
	}
}

func (mapper *OpenContrailMapper) linkToVhost(node *graph.Node) {
	name := node.Metadata()["Name"].(string)
	if mapper.vHost != nil {
		md := graph.Metadata{"RelationType": "layer2"}
		if !mapper.graph.AreLinked(node, mapper.vHost, md) {
			logging.GetLogger().Debugf("Link %s to %s", name, mapper.vHost.Metadata()["Name"].(string))
			mapper.graph.Link(node, mapper.vHost, md)
		}
	} else {
		logging.GetLogger().Debugf("Add node %s to pending link list", name)
		mapper.pendingLinks = append(mapper.pendingLinks, node)
	}
}

func (mapper *NeutronMapper) EnhanceNode(node *graph.Node) {
	mac, ok := node.Metadata()["MAC"]
	if !ok {
		return
	}

	portMd, f := mapper.cache.Get(mac.(string))
	// If port metadatas have not changed, we return
	if f && portMd == retrievePortMetadata(node.Metadata()) {
		return
	}

	mapper.nodeUpdaterChan <- node.ID
}

func (o *OvsSFlowProbesHandler) RegisterProbe(n *graph.Node, capture *api.Capture, ft *flow.Table) error {
	tid, ok := n.Metadata()["TID"]
	if !ok {
		return fmt.Errorf("No TID for node %v", n)
	}

	if isOvsBridge(n) {
		err := o.RegisterProbeOnBridge(n.Metadata()["UUID"].(string), tid.(string), ft)
		if err != nil {
			return err
		}
	}
	return nil
}

func getGoPacketFirstLayerType(n *graph.Node) gopacket.LayerType {
	switch n.Metadata()["Type"].(string) {
	case "bridge", "bond", "can", "dummy", "hsr", "ifb", "macvlan", "macvtap",
		"veth", "vlan", "vxlan", "gretap", "ip6gretap", "geneve":
		return layers.LayerTypeEthernet
	case "ipoib", "vcan", "ipip", "ipvlan", "lowpan":
		return layers.LayerTypeIPv4
	case "gre":
		return flow.LayerTypeInGRE
	case "ip6tnl", "ip6gre", "sit":
		return layers.LayerTypeIPv6
	}
	return layers.LayerTypeLinuxSLL
}

func (u *NetLinkProbe) handleIntfIsChild(intf *graph.Node, link netlink.Link) {
	// handle pending relationship
	u.linkPendingChildren(intf, int64(link.Attrs().Index))

	// interface being a part of a bridge
	if link.Attrs().MasterIndex != 0 {
		u.linkIntfToIndex(intf, int64(link.Attrs().MasterIndex))
	}

	if link.Attrs().ParentIndex != 0 {
		if _, ok := intf.Metadata()["Vlan"]; ok {
			u.linkIntfToIndex(intf, int64(int64(link.Attrs().ParentIndex)))
		}
	}
}

func (mapper *OpenContrailMapper) enhanceNode(node *graph.Node) {
	// To break update loops
	if _, ok := node.Metadata()["ExtID/attached-mac"]; ok {
		return
	}

	ifType, ok := node.Metadata()["Type"]
	if !ok {
		return
	}

	if ifType != "host" && ifType != "netns" {
		mapper.nodeUpdaterChan <- node.ID
	}
}

func (mapper *NeutronMapper) updateNode(node *graph.Node, attrs *Attributes) {
	mapper.graph.Lock()

	tr := mapper.graph.StartMetadataTransaction(node)
	tr.AddMetadata("Manager", "neutron")

	if attrs.PortID != "" {
		tr.AddMetadata("Neutron/PortID", attrs.PortID)
	}

	if attrs.TenantID != "" {
		tr.AddMetadata("Neutron/TenantID", attrs.TenantID)
	}

	if attrs.NetworkID != "" {
		tr.AddMetadata("Neutron/NetworkID", attrs.NetworkID)
	}

	if attrs.NetworkName != "" {
		tr.AddMetadata("Neutron/NetworkName", attrs.NetworkName)
	}

	if segID, err := strconv.Atoi(attrs.VNI); err != nil && segID > 0 {
		tr.AddMetadata("Neutron/VNI", uint64(segID))
	}

	var registerLink *FabricRegisterLinkWSMessage
	if vm, ok := node.Metadata()["ExtID/vm-uuid"]; ok {
		if mac, ok := node.Metadata()["ExtID/attached-mac"]; ok {
			if path := mapper.graph.LookupShortestPath(node, graph.Metadata{"Type": "tun"}, graph.Metadata{"RelationType": "layer2"}); len(path) > 0 {
				registerLink = &FabricRegisterLinkWSMessage{
					ParentNodeID:   path[len(path)-1].ID,
					ParentMetadata: graph.Metadata{"Type": "host", "InstanceID": vm},
					ChildMetadata:  graph.Metadata{"Type": "device", "MAC": mac},
				}
			}
		}
	}
	tr.Commit()
	mapper.graph.Unlock()

	if registerLink != nil {
		msg := shttp.NewWSMessage(FabricNamespace, "RegisterLink", registerLink)
		mapper.wsClient.SendWSMessage(msg)
	}
}

func (t *TIDMapper) setTID(parent, child *graph.Node) {
	if t, ok := child.Metadata()["Type"]; !ok || t == "" {
		return
	}

	if tid, ok := parent.Metadata()["TID"]; ok {
		tid = tid.(string) + child.Metadata()["Name"].(string) + child.Metadata()["Type"].(string)
		u, _ := uuid.NewV5(uuid.NamespaceOID, []byte(tid.(string)))
		t.Graph.AddMetadata(child, "TID", u.String())
	}
}

func getGoPacketFirstLayerType(n *graph.Node) gopacket.LayerType {
	if encapType, ok := n.Metadata()["EncapType"]; ok {
		switch encapType.(string) {
		case "ether":
			return layers.LayerTypeEthernet
		case "gre":
			return flow.LayerTypeInGRE
		case "sit", "ipip":
			return layers.LayerTypeIPv4
		case "tunnel6", "gre6":
			return layers.LayerTypeIPv6
		default:
			logging.GetLogger().Warningf("Encapsulation unknown %s on link %s, defaulting to Ethernet", encapType, n.Metadata()["Name"])
		}
	} else {
		logging.GetLogger().Warningf("EncapType not found on link %s, defaulting to Ethernet", n.Metadata()["Name"])
	}
	return layers.LayerTypeEthernet
}

func (p *GoPacketProbesHandler) RegisterProbe(n *graph.Node, capture *api.Capture, ft *flow.Table) error {
	name, ok := n.Metadata()["Name"]
	if !ok || name == "" {
		return fmt.Errorf("No name for node %v", n)
	}

	encapType, ok := n.Metadata()["EncapType"]
	if !ok || encapType == "" {
		return fmt.Errorf("No EncapType for node %v", n)
	}

	tid, ok := n.Metadata()["TID"]
	if !ok {
		return fmt.Errorf("No TID for node %v", n)
	}

	id := string(n.ID)
	ifName := name.(string)

	if _, ok = p.probes[id]; ok {
		return fmt.Errorf("Already registered %s", ifName)
	}

	port, ok := n.Metadata()["MPLSUDPPort"].(int)
	if ok {
		// All gopacket instance of this agent will classify UDP packets coming
		// from UDP port MPLSUDPPort as MPLS whatever the source interface
		layers.RegisterUDPPortLayerType(layers.UDPPort(port), layers.LayerTypeMPLS)
		logging.GetLogger().Infof("MPLSoUDP port: %v", port)
	}

	probe := &GoPacketProbe{
		NodeTID:   tid.(string),
		state:     common.StoppedState,
		flowTable: ft,
	}

	p.probesLock.Lock()
	p.probes[id] = probe
	p.probesLock.Unlock()
	p.wg.Add(1)

	go func() {
		defer p.wg.Done()

		probe.run(p.graph, n, capture)
	}()

	return nil
}

func NewNetNSContextByNode(g *graph.Graph, n *graph.Node) (*common.NetNSContext, error) {
	name, ok := n.Metadata()["Name"]
	if !ok || name == "" {
		return nil, fmt.Errorf("No name for node %v", n)
	}
	ifName := name.(string)

	nodes := g.LookupShortestPath(n, graph.Metadata{"Type": "host"}, graph.Metadata{"RelationType": "ownership"})
	if len(nodes) == 0 {
		return nil, fmt.Errorf("Failed to determine probePath for %s", ifName)
	}

	for _, node := range nodes {
		if node.Metadata()["Type"] == "netns" {
			name := node.Metadata()["Name"].(string)
			path := node.Metadata()["Path"].(string)
			logging.GetLogger().Debugf("Switching to namespace %s (path: %s)", name, path)

			return common.NewNetNsContext(path)
		}
	}

	return nil, nil
}