Implement host probing retry with major refactoring
- Implement probe retry
- Switch to typical core/provider design pattern for HostProbingService
and as a result decoupling the dependency between SR and HostLocationProvider
Change-Id: I33a15af580677ea376b421ac3e26f9821dcca844
diff --git a/providers/host/src/main/java/org/onosproject/provider/host/impl/HostLocationProvider.java b/providers/host/src/main/java/org/onosproject/provider/host/impl/HostLocationProvider.java
index dc58dcc..40e67b5 100644
--- a/providers/host/src/main/java/org/onosproject/provider/host/impl/HostLocationProvider.java
+++ b/providers/host/src/main/java/org/onosproject/provider/host/impl/HostLocationProvider.java
@@ -54,7 +54,6 @@
import org.onosproject.cfg.ComponentConfigService;
import org.onosproject.core.ApplicationId;
import org.onosproject.core.CoreService;
-import org.onosproject.net.host.HostLocationProbingService;
import org.onosproject.net.intf.InterfaceService;
import org.onosproject.net.ConnectPoint;
import org.onosproject.net.Device;
@@ -93,12 +92,9 @@
import java.util.Objects;
import java.util.Optional;
import java.util.concurrent.ExecutorService;
-import java.util.concurrent.ScheduledExecutorService;
-import java.util.concurrent.TimeUnit;
import java.util.stream.Stream;
import java.util.Set;
-import static java.util.concurrent.Executors.newScheduledThreadPool;
import static java.util.concurrent.Executors.newSingleThreadScheduledExecutor;
import static org.onlab.util.Tools.groupedThreads;
import static org.slf4j.LoggerFactory.getLogger;
@@ -109,7 +105,7 @@
*/
@Component(immediate = true)
@Service
-public class HostLocationProvider extends AbstractProvider implements HostProvider, HostLocationProbingService {
+public class HostLocationProvider extends AbstractProvider implements HostProvider {
private final Logger log = getLogger(getClass());
@Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
@@ -136,8 +132,6 @@
@Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
protected InterfaceService interfaceService;
- private HostProviderService providerService;
-
private final InternalHostProvider processor = new InternalHostProvider();
private final DeviceListener deviceListener = new InternalDeviceListener();
@@ -173,11 +167,11 @@
label = "Allow hosts to be multihomed")
private boolean multihomingEnabled = false;
- private int probeInitDelayMs = 1000;
+ private HostProviderService providerService;
- ExecutorService eventHandler;
+ ExecutorService deviceEventHandler;
+ private ExecutorService probeEventHandler;
private ExecutorService packetHandler;
- private ScheduledExecutorService hostProber;
/**
* Creates an OpenFlow host provider.
@@ -190,10 +184,12 @@
public void activate(ComponentContext context) {
cfgService.registerProperties(getClass());
appId = coreService.registerApplication("org.onosproject.provider.host");
- eventHandler = newSingleThreadScheduledExecutor(groupedThreads("onos/host-loc-provider", "event-handler", log));
+ deviceEventHandler = newSingleThreadScheduledExecutor(groupedThreads("onos/host-loc-provider",
+ "device-event-handler", log));
+ probeEventHandler = newSingleThreadScheduledExecutor(groupedThreads("onos/host-loc-provider",
+ "probe-event-handler", log));
packetHandler = newSingleThreadScheduledExecutor(groupedThreads("onos/host-loc-provider",
"packet-handler", log));
- hostProber = newScheduledThreadPool(32, groupedThreads("onos/host-loc-probe", "%d", log));
providerService = providerRegistry.register(this);
packetService.addProcessor(processor, PacketProcessor.advisor(1));
deviceService.addListener(deviceListener);
@@ -212,9 +208,9 @@
providerRegistry.unregister(this);
packetService.removeProcessor(processor);
deviceService.removeListener(deviceListener);
- eventHandler.shutdown();
+ deviceEventHandler.shutdown();
+ probeEventHandler.shutdown();
packetHandler.shutdown();
- hostProber.shutdown();
providerService = null;
log.info("Stopped");
}
@@ -354,47 +350,6 @@
}
@Override
- public void probeHostLocation(Host host, ConnectPoint connectPoint, ProbeMode probeMode) {
- host.ipAddresses().stream().findFirst().ifPresent(ip -> {
- MacAddress probeMac = providerService.addPendingHostLocation(host.id(), connectPoint, probeMode);
- log.debug("Constructing {} probe for host {} with {}", probeMode, host.id(), ip);
- Ethernet probe;
- if (ip.isIp4()) {
- probe = ARP.buildArpRequest(probeMac.toBytes(), Ip4Address.ZERO.toOctets(),
- host.id().mac().toBytes(), ip.toOctets(),
- host.id().mac().toBytes(), host.id().vlanId().toShort());
- } else {
- probe = NeighborSolicitation.buildNdpSolicit(
- ip.getIp6Address(),
- Ip6Address.valueOf(IPv6.getLinkLocalAddress(probeMac.toBytes())),
- ip.getIp6Address(),
- probeMac,
- host.id().mac(),
- host.id().vlanId());
- }
-
- // NOTE: delay the probe a little bit to wait for the store synchronization is done
- hostProber.schedule(() ->
- sendLocationProbe(probe, connectPoint), probeInitDelayMs, TimeUnit.MILLISECONDS);
- });
- }
-
- /**
- * Send the probe packet on given port.
- *
- * @param probe the probe packet
- * @param connectPoint the port we want to probe
- */
- private void sendLocationProbe(Ethernet probe, ConnectPoint connectPoint) {
- log.debug("Sending probe for host {} on location {} with probeMac {}",
- probe.getDestinationMAC(), connectPoint, probe.getSourceMAC());
- TrafficTreatment treatment = DefaultTrafficTreatment.builder().setOutput(connectPoint.port()).build();
- OutboundPacket outboundPacket = new DefaultOutboundPacket(connectPoint.deviceId(),
- treatment, ByteBuffer.wrap(probe.serialize()));
- packetService.emit(outboundPacket);
- }
-
- @Override
public void triggerProbe(Host host) {
//log.info("Triggering probe on device {} ", host);
@@ -465,10 +420,8 @@
if (prevLocations.stream().noneMatch(loc -> loc.deviceId().equals(hloc.deviceId()))) {
// New location is on a device that we haven't seen before
- // Could be a dual-home host. Append new location and send out the probe
+ // Could be a dual-home host.
newLocations.addAll(prevLocations);
- prevLocations.forEach(prevLocation ->
- probeHostLocation(existingHost, prevLocation, ProbeMode.VERIFY));
} else {
// Move within the same switch
// Simply replace old location that is on the same device
@@ -559,10 +512,8 @@
HostId hid = HostId.hostId(eth.getSourceMAC(), vlan);
MacAddress destMac = eth.getDestinationMAC();
- // Receives a location probe. Invalid entry from the cache
+ // Ignore location probes
if (multihomingEnabled && destMac.isOnos() && !MacAddress.NONE.equals(destMac)) {
- log.debug("Receives probe for {}/{} on {}", srcMac, vlan, heardOn);
- providerService.removePendingHostLocation(destMac);
return;
}
@@ -762,7 +713,7 @@
private class InternalDeviceListener implements DeviceListener {
@Override
public void event(DeviceEvent event) {
- eventHandler.execute(() -> handleEvent(event));
+ deviceEventHandler.execute(() -> handleEvent(event));
}
private void handleEvent(DeviceEvent event) {
diff --git a/providers/host/src/test/java/org/onosproject/provider/host/impl/HostLocationProviderTest.java b/providers/host/src/test/java/org/onosproject/provider/host/impl/HostLocationProviderTest.java
index e00617d..89a6ef8 100644
--- a/providers/host/src/test/java/org/onosproject/provider/host/impl/HostLocationProviderTest.java
+++ b/providers/host/src/test/java/org/onosproject/provider/host/impl/HostLocationProviderTest.java
@@ -236,7 +236,7 @@
provider.activate(CTX_FOR_NO_REMOVE);
- provider.eventHandler = MoreExecutors.newDirectExecutorService();
+ provider.deviceEventHandler = MoreExecutors.newDirectExecutorService();
}
@Test
diff --git a/providers/hostprobing/BUCK b/providers/hostprobing/BUCK
new file mode 100644
index 0000000..21bf493
--- /dev/null
+++ b/providers/hostprobing/BUCK
@@ -0,0 +1,22 @@
+COMPILE_DEPS = [
+ '//lib:CORE_DEPS',
+ '//incubator/api:onos-incubator-api',
+]
+
+TEST_DEPS = [
+ '//lib:TEST_ADAPTERS',
+ '//utils/osgi:onlab-osgi-tests',
+]
+
+osgi_jar_with_tests (
+ deps = COMPILE_DEPS,
+ test_deps = TEST_DEPS,
+)
+
+onos_app (
+ app_name = 'org.onosproject.hostprobingprovider',
+ title = 'Host Probing Provider',
+ category = 'Provider',
+ url = 'http://onosproject.org',
+ description = 'Provides host probing mechanism that discovers or verifies the existence of a host at specific location',
+)
diff --git a/providers/hostprobing/pom.xml b/providers/hostprobing/pom.xml
new file mode 100644
index 0000000..3f3c001
--- /dev/null
+++ b/providers/hostprobing/pom.xml
@@ -0,0 +1,72 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+ ~ Copyright 2014-present Open Networking Foundation
+ ~
+ ~ Licensed under the Apache License, Version 2.0 (the "License");
+ ~ you may not use this file except in compliance with the License.
+ ~ You may obtain a copy of the License at
+ ~
+ ~ http://www.apache.org/licenses/LICENSE-2.0
+ ~
+ ~ Unless required by applicable law or agreed to in writing, software
+ ~ distributed under the License is distributed on an "AS IS" BASIS,
+ ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ ~ See the License for the specific language governing permissions and
+ ~ limitations under the License.
+ -->
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+ xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+ xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+ <modelVersion>4.0.0</modelVersion>
+
+ <parent>
+ <groupId>org.onosproject</groupId>
+ <artifactId>onos-providers</artifactId>
+ <version>1.12.1-SNAPSHOT</version>
+ </parent>
+
+ <artifactId>onos-host-provider</artifactId>
+ <packaging>bundle</packaging>
+
+ <properties>
+ <onos.app.name>org.onosproject.hostprobingprovider</onos.app.name>
+ <onos.app.title>Host Probing Provider</onos.app.title>
+ <onos.app.origin>ONF</onos.app.origin>
+ <onos.app.category>Provider</onos.app.category>
+ <onos.app.url>http://onosproject.org</onos.app.url>
+ <onos.app.readme>Provides host probing mechanism that discovers or verifies the existence of a host at specific location</onos.app.readme>
+ </properties>
+
+ <description>ONOS host probing provider</description>
+ <dependencies>
+ <dependency>
+ <groupId>org.onosproject</groupId>
+ <artifactId>onos-api</artifactId>
+ <classifier>tests</classifier>
+ <scope>test</scope>
+ </dependency>
+ <dependency>
+ <groupId>org.osgi</groupId>
+ <artifactId>org.osgi.core</artifactId>
+ </dependency>
+ <dependency>
+ <groupId>org.osgi</groupId>
+ <artifactId>org.osgi.compendium</artifactId>
+ </dependency>
+ <dependency>
+ <groupId>org.onosproject</groupId>
+ <artifactId>onlab-osgi</artifactId>
+ <classifier>tests</classifier>
+ <scope>test</scope>
+ </dependency>
+ <dependency>
+ <groupId>org.easymock</groupId>
+ <artifactId>easymock</artifactId>
+ <scope>test</scope>
+ </dependency>
+ <dependency>
+ <groupId>org.onosproject</groupId>
+ <artifactId>onos-incubator-api</artifactId>
+ </dependency>
+ </dependencies>
+</project>
diff --git a/providers/hostprobing/src/main/java/org/onosproject/provider/hostprobing/impl/DefaultHostProbingProvider.java b/providers/hostprobing/src/main/java/org/onosproject/provider/hostprobing/impl/DefaultHostProbingProvider.java
new file mode 100644
index 0000000..dfcbf0b
--- /dev/null
+++ b/providers/hostprobing/src/main/java/org/onosproject/provider/hostprobing/impl/DefaultHostProbingProvider.java
@@ -0,0 +1,252 @@
+/*
+ * Copyright 2018-present Open Networking Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.onosproject.provider.hostprobing.impl;
+
+import org.apache.felix.scr.annotations.Activate;
+import org.apache.felix.scr.annotations.Component;
+import org.apache.felix.scr.annotations.Deactivate;
+import org.apache.felix.scr.annotations.Reference;
+import org.apache.felix.scr.annotations.ReferenceCardinality;
+import org.apache.felix.scr.annotations.Service;
+import org.onlab.packet.ARP;
+import org.onlab.packet.Ethernet;
+import org.onlab.packet.IPv6;
+import org.onlab.packet.Ip4Address;
+import org.onlab.packet.Ip6Address;
+import org.onlab.packet.IpAddress;
+import org.onlab.packet.MacAddress;
+import org.onlab.packet.VlanId;
+import org.onlab.packet.ndp.NeighborSolicitation;
+import org.onosproject.mastership.MastershipService;
+import org.onosproject.net.ConnectPoint;
+import org.onosproject.net.Host;
+import org.onosproject.net.HostLocation;
+import org.onosproject.net.flow.DefaultTrafficTreatment;
+import org.onosproject.net.flow.TrafficTreatment;
+import org.onosproject.net.host.HostProbe;
+import org.onosproject.net.host.HostProbingEvent;
+import org.onosproject.net.host.HostProbingProvider;
+import org.onosproject.net.host.HostProbingProviderRegistry;
+import org.onosproject.net.host.HostProbingProviderService;
+import org.onosproject.net.host.HostProvider;
+import org.onosproject.net.host.HostProviderRegistry;
+import org.onosproject.net.host.HostProviderService;
+import org.onosproject.net.host.ProbeMode;
+import org.onosproject.net.packet.DefaultOutboundPacket;
+import org.onosproject.net.packet.OutboundPacket;
+import org.onosproject.net.packet.PacketProcessor;
+import org.onosproject.net.packet.PacketService;
+import org.onosproject.net.provider.AbstractProvider;
+import org.onosproject.net.provider.ProviderId;
+import org.osgi.service.component.ComponentContext;
+import org.slf4j.Logger;
+
+import java.nio.ByteBuffer;
+import java.util.Optional;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
+
+import static java.util.concurrent.Executors.newScheduledThreadPool;
+import static java.util.concurrent.Executors.newSingleThreadScheduledExecutor;
+import static org.onlab.util.Tools.groupedThreads;
+import static org.slf4j.LoggerFactory.getLogger;
+
+/**
+ * Provider which sends host location probes to discover or verify a host at specific location.
+ */
+@Component(immediate = true)
+@Service
+public class DefaultHostProbingProvider extends AbstractProvider implements HostProvider, HostProbingProvider {
+ private final Logger log = getLogger(getClass());
+
+ @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+ private HostProviderRegistry providerRegistry;
+
+ @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+ private HostProbingProviderRegistry hostProbingProviderRegistry;
+
+ @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+ private PacketService packetService;
+
+ @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+ private MastershipService mastershipService;
+
+ private HostProviderService providerService;
+ private HostProbingProviderService hostProbingProviderService;
+ private ExecutorService packetHandler;
+ private ExecutorService probeEventHandler;
+ private ScheduledExecutorService hostProber;
+
+ private final PacketProcessor packetProcessor = context ->
+ packetHandler.execute(() -> {
+ Ethernet eth = context.inPacket().parsed();
+ if (eth == null) {
+ return;
+ }
+ MacAddress srcMac = eth.getSourceMAC();
+ MacAddress destMac = eth.getDestinationMAC();
+ VlanId vlan = VlanId.vlanId(eth.getVlanID());
+ ConnectPoint heardOn = context.inPacket().receivedFrom();
+
+ // Receives a location probe. Invalid entry from the cache
+ if (destMac.isOnos() && !MacAddress.NONE.equals(destMac)) {
+ log.debug("Receives probe for {}/{} on {}", srcMac, vlan, heardOn);
+ hostProbingProviderService.removeProbingHost(destMac);
+ }
+ });
+
+ // TODO Make this configurable
+ private static final int PROBE_INIT_DELAY_MS = 1000;
+ private static final int DEFAULT_RETRY = 5;
+
+ /**
+ * Creates an OpenFlow host provider.
+ */
+ public DefaultHostProbingProvider() {
+ super(new ProviderId("hostprobing", "org.onosproject.provider.hostprobing"));
+ }
+
+ @Activate
+ public void activate(ComponentContext context) {
+ providerService = providerRegistry.register(this);
+ hostProbingProviderService = hostProbingProviderRegistry.register(this);
+
+ packetHandler = newSingleThreadScheduledExecutor(groupedThreads("onos/host-loc-provider",
+ "packet-handler", log));
+ probeEventHandler = newSingleThreadScheduledExecutor(groupedThreads("onos/host-loc-provider",
+ "probe-handler", log));
+ hostProber = newScheduledThreadPool(32, groupedThreads("onos/host-loc-probe", "%d", log));
+
+ packetService.addProcessor(packetProcessor, PacketProcessor.advisor(1));
+ }
+
+ @Deactivate
+ public void deactivate() {
+ providerRegistry.unregister(this);
+ hostProbingProviderRegistry.unregister(this);
+ providerService = null;
+
+ packetService.removeProcessor(packetProcessor);
+
+ packetHandler.shutdown();
+ probeEventHandler.shutdown();
+ hostProber.shutdown();
+ }
+
+ @Override
+ public void triggerProbe(Host host) {
+ // Not doing anything at this moment...
+ }
+
+ @Override
+ public void processEvent(HostProbingEvent event) {
+ probeEventHandler.execute(() -> {
+ log.debug("Receiving HostProbingEvent {}", event);
+ HostProbe hostProbe = event.subject();
+
+ switch (event.type()) {
+ case PROBE_REQUESTED:
+ // Do nothing
+ break;
+ case PROBE_TIMEOUT:
+ // Retry probe until PROBE_FAIL
+ // TODO Only retry DISCOVER probes
+ probeHostInternal(hostProbe, hostProbe.connectPoint(),
+ hostProbe.mode(), hostProbe.probeMac(), hostProbe.retry());
+ break;
+ case PROBE_FAIL:
+ // Remove this location if this is a verify probe.
+ if (hostProbe.mode() == ProbeMode.VERIFY) {
+ providerService.removeLocationFromHost(hostProbe.id(),
+ (HostLocation) hostProbe.connectPoint());
+ }
+ break;
+ case PROBE_COMPLETED:
+ // Add this location if this is a discover probe.
+ if (hostProbe.mode() == ProbeMode.DISCOVER) {
+ HostLocation newLocation = new HostLocation(hostProbe.connectPoint(),
+ System.currentTimeMillis());
+ providerService.addLocationToHost(hostProbe.id(), newLocation);
+ }
+ break;
+ default:
+ log.warn("Unknown HostProbingEvent type: {}", event.type());
+ }
+ });
+ }
+
+ @Override
+ public void probeHost(Host host, ConnectPoint connectPoint, ProbeMode probeMode) {
+ probeHostInternal(host, connectPoint, probeMode, null, DEFAULT_RETRY);
+ }
+
+ // probeMac can be null if this is the very first probe and the mac is to-be-generated.
+ private void probeHostInternal(Host host, ConnectPoint connectPoint, ProbeMode probeMode,
+ MacAddress probeMac, int retry) {
+ if (!mastershipService.isLocalMaster(connectPoint.deviceId())) {
+ log.debug("Current node is not master of {}, abort probing {}", connectPoint.deviceId(), host);
+ return;
+ }
+
+ log.debug("probeHostInternal host={}, cp={}, mode={}, probeMac={}, retry={}", host, connectPoint,
+ probeMode, probeMac, retry);
+ Optional<IpAddress> ipOptional = host.ipAddresses().stream().findFirst();
+
+ if (ipOptional.isPresent()) {
+ probeMac = hostProbingProviderService.addProbingHost(host, connectPoint, probeMode, probeMac, retry);
+
+ IpAddress ip = ipOptional.get();
+ log.debug("Constructing {} probe for host {} with {}", probeMode, host.id(), ip);
+ Ethernet probe;
+ if (ip.isIp4()) {
+ probe = ARP.buildArpRequest(probeMac.toBytes(), Ip4Address.ZERO.toOctets(),
+ host.id().mac().toBytes(), ip.toOctets(),
+ host.id().mac().toBytes(), host.id().vlanId().toShort());
+ } else {
+ probe = NeighborSolicitation.buildNdpSolicit(
+ ip.getIp6Address(),
+ Ip6Address.valueOf(IPv6.getLinkLocalAddress(probeMac.toBytes())),
+ ip.getIp6Address(),
+ probeMac,
+ host.id().mac(),
+ host.id().vlanId());
+ }
+
+ // NOTE: delay the probe a little bit to wait for the store synchronization is done
+ hostProber.schedule(() ->
+ sendLocationProbe(probe, connectPoint), PROBE_INIT_DELAY_MS, TimeUnit.MILLISECONDS);
+ } else {
+ log.debug("Host {} has no IP address yet. Skip probing.", host);
+ }
+ }
+
+ /**
+ * Send the probe packet on given port.
+ *
+ * @param probe the probe packet
+ * @param connectPoint the port we want to probe
+ */
+ private void sendLocationProbe(Ethernet probe, ConnectPoint connectPoint) {
+ log.debug("Sending probe for host {} on location {} with probeMac {}",
+ probe.getDestinationMAC(), connectPoint, probe.getSourceMAC());
+ TrafficTreatment treatment = DefaultTrafficTreatment.builder().setOutput(connectPoint.port()).build();
+ OutboundPacket outboundPacket = new DefaultOutboundPacket(connectPoint.deviceId(),
+ treatment, ByteBuffer.wrap(probe.serialize()));
+ packetService.emit(outboundPacket);
+ }
+}
\ No newline at end of file
diff --git a/providers/hostprobing/src/main/java/org/onosproject/provider/hostprobing/impl/package-info.java b/providers/hostprobing/src/main/java/org/onosproject/provider/hostprobing/impl/package-info.java
new file mode 100644
index 0000000..60ef748
--- /dev/null
+++ b/providers/hostprobing/src/main/java/org/onosproject/provider/hostprobing/impl/package-info.java
@@ -0,0 +1,20 @@
+/*
+ * Copyright 2018-present Open Networking Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * Provider that uses packet service as a means of host discovery and tracking.
+ */
+package org.onosproject.provider.hostprobing.impl;
diff --git a/providers/pom.xml b/providers/pom.xml
index 5e030df..7cfca17 100644
--- a/providers/pom.xml
+++ b/providers/pom.xml
@@ -33,6 +33,7 @@
<modules>
<module>openflow</module>
<module>host</module>
+ <module>hostprobing</module>
<module>netcfghost</module>
<module>netconf</module>
<module>null</module>