openstack/net-virt-providers/src/main/java/org/opendaylight/ovsdb/openstack/netvirt/providers/openflow13/services/arp/GatewayMacResolverService.java

   1 /*
   2  * Copyright (c) 2015 Brocade Communications Systems, Inc. and others.  All rights reserved.
   3  *
   4  * This program and the accompanying materials are made available under the
   5  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
   6  * and is available at http://www.eclipse.org/legal/epl-v10.html
   7  */
   8 package org.opendaylight.ovsdb.openstack.netvirt.providers.openflow13.services.arp;
   9
  10 import com.google.common.base.Preconditions;
  11 import com.google.common.collect.ImmutableList;
  12 import com.google.common.util.concurrent.FutureCallback;
  13 import com.google.common.util.concurrent.Futures;
  14 import com.google.common.util.concurrent.JdkFutureAdapters;
  15 import com.google.common.util.concurrent.ListenableFuture;
  16 import com.google.common.util.concurrent.ListeningExecutorService;
  17 import com.google.common.util.concurrent.MoreExecutors;
  18 import org.opendaylight.controller.sal.binding.api.BindingAwareBroker.ProviderContext;
  19 import org.opendaylight.openflowplugin.api.OFConstants;
  20 import org.opendaylight.ovsdb.openstack.netvirt.api.ConfigurationService;
  21 import org.opendaylight.ovsdb.openstack.netvirt.api.GatewayMacResolver;
  22 import org.opendaylight.ovsdb.openstack.netvirt.api.GatewayMacResolverListener;
  23 import org.opendaylight.ovsdb.openstack.netvirt.api.NodeCacheManager;
  24 import org.opendaylight.ovsdb.openstack.netvirt.providers.ConfigInterface;
  25 import org.opendaylight.ovsdb.openstack.netvirt.providers.NetvirtProvidersProvider;
  26 import org.opendaylight.ovsdb.openstack.netvirt.providers.openflow13.AbstractServiceInstance;
  27 import org.opendaylight.ovsdb.openstack.netvirt.providers.openflow13.Service;
  28 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev100924.Ipv4Address;
  29 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.yang.types.rev100924.MacAddress;
  30 import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.inventory.rev130819.FlowCapableNode;
  31 import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.inventory.rev130819.FlowId;
  32 import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.inventory.rev130819.tables.Table;
  33 import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.inventory.rev130819.tables.TableKey;
  34 import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.inventory.rev130819.tables.table.Flow;
  35 import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.inventory.rev130819.tables.table.FlowBuilder;
  36 import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.inventory.rev130819.tables.table.FlowKey;
  37 import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.service.rev130819.AddFlowInputBuilder;
  38 import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.service.rev130819.AddFlowOutput;
  39 import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.service.rev130819.RemoveFlowInputBuilder;
  40 import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.service.rev130819.SalFlowService;
  41 import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.types.rev131026.FlowCookie;
  42 import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.types.rev131026.FlowModFlags;
  43 import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.types.rev131026.FlowRef;
  44 import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.types.rev131026.flow.InstructionsBuilder;
  45 import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.types.rev131026.flow.Match;
  46 import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.types.rev131026.flow.MatchBuilder;
  47 import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.types.rev131026.instruction.instruction.ApplyActionsCaseBuilder;
  48 import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.types.rev131026.instruction.instruction.apply.actions._case.ApplyActions;
  49 import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.types.rev131026.instruction.instruction.apply.actions._case.ApplyActionsBuilder;
  50 import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.types.rev131026.instruction.list.Instruction;
  51 import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.types.rev131026.instruction.list.InstructionBuilder;
  52 import org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.NodeRef;
  53 import org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.Nodes;
  54 import org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.node.NodeConnector;
  55 import org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.node.NodeConnectorKey;
  56 import org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.nodes.Node;
  57 import org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.nodes.NodeKey;
  58 import org.opendaylight.yang.gen.v1.urn.opendaylight.model.match.types.rev131026.match.EthernetMatch;
  59 import org.opendaylight.yang.gen.v1.urn.opendaylight.model.match.types.rev131026.match.layer._3.match.ArpMatch;
  60 import org.opendaylight.yang.gen.v1.urn.opendaylight.packet.service.rev130709.PacketProcessingListener;
  61 import org.opendaylight.yang.gen.v1.urn.opendaylight.packet.service.rev130709.PacketProcessingService;
  62 import org.opendaylight.yang.gen.v1.urn.opendaylight.packet.service.rev130709.PacketReceived;
  63 import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
  64 import org.opendaylight.yangtools.yang.binding.KeyedInstanceIdentifier;
  65 import org.opendaylight.yangtools.yang.common.RpcResult;
  66 import org.osgi.framework.BundleContext;
  67 import org.osgi.framework.ServiceReference;
  68 import org.slf4j.Logger;
  69 import org.slf4j.LoggerFactory;
  70
  71 import java.math.BigInteger;
  72 import java.util.Collections;
  73 import java.util.List;
  74 import java.util.Map.Entry;
  75 import java.util.concurrent.Callable;
  76 import java.util.concurrent.ConcurrentHashMap;
  77 import java.util.concurrent.ConcurrentMap;
  78 import java.util.concurrent.Executors;
  79 import java.util.concurrent.Future;
  80 import java.util.concurrent.ScheduledExecutorService;
  81 import java.util.concurrent.TimeUnit;
  82 import java.util.concurrent.atomic.AtomicBoolean;
  83 import java.util.concurrent.atomic.AtomicLong;
  84
  85 import static com.google.common.base.Preconditions.checkNotNull;
  86
  87 /**
  88  *
  89  * @author Anil Vishnoi (avishnoi@Brocade.com)
  90  *
  91  */
  92 public class GatewayMacResolverService extends AbstractServiceInstance
  93                                         implements ConfigInterface, GatewayMacResolver,PacketProcessingListener {
  94
  95     private static final Logger LOG = LoggerFactory.getLogger(GatewayMacResolverService.class);
  96     private static final short TABLE_FOR_ARP_FLOW = 0;
  97     private static final String ARP_REPLY_TO_CONTROLLER_FLOW_NAME = "GatewayArpReplyRouter";
  98     private static final int ARP_REPLY_TO_CONTROLLER_FLOW_PRIORITY = 10000;
  99     private static final Instruction SEND_TO_CONTROLLER_INSTRUCTION;
 100     private ArpSender arpSender;
 101     private SalFlowService flowService;
 102     private final AtomicLong flowCookie = new AtomicLong();
 103     private final ConcurrentMap<Ipv4Address, ArpResolverMetadata> gatewayToArpMetadataMap =
 104             new ConcurrentHashMap<>();
 105     private static final int ARP_WATCH_BROTHERS = 10;
 106     private static final int WAIT_CYCLES = 3;
 107     private static final int PER_CYCLE_WAIT_DURATION = 1000;
 108     private static final int REFRESH_INTERVAL = 10;
 109     private final ListeningExecutorService arpWatcherWall = MoreExecutors.listeningDecorator(Executors.newFixedThreadPool(ARP_WATCH_BROTHERS));
 110     private final ScheduledExecutorService gatewayMacRefresherPool = Executors.newScheduledThreadPool(1);
 111     private final ScheduledExecutorService refreshRequester = Executors.newSingleThreadScheduledExecutor();
 112     private AtomicBoolean initializationDone = new AtomicBoolean(false);
 113     private volatile ConfigurationService configurationService;
 114     private volatile NodeCacheManager nodeCacheManager;
 115
 116     static {
 117         ApplyActions applyActions = new ApplyActionsBuilder().setAction(
 118                 ImmutableList.of(ArpFlowFactory.createSendToControllerAction(0))).build();
 119         SEND_TO_CONTROLLER_INSTRUCTION = new InstructionBuilder().setOrder(0)
 120             .setInstruction(new ApplyActionsCaseBuilder().setApplyActions(applyActions).build())
 121             .build();
 122     }
 123
 124     public GatewayMacResolverService(){
 125         super(Service.GATEWAY_RESOLVER);
 126     }
 127
 128     public GatewayMacResolverService(Service service){
 129         super(service);
 130     }
 131
 132     private void init(){
 133         if(!initializationDone.get()){
 134             initializationDone.set(true);
 135             ProviderContext providerContext = NetvirtProvidersProvider.getProviderContext();
 136             checkNotNull(providerContext);
 137             PacketProcessingService packetProcessingService = providerContext.getRpcService(PacketProcessingService.class);
 138             if (packetProcessingService != null) {
 139                 LOG.debug("{} was found.", PacketProcessingService.class.getSimpleName());
 140                 this.arpSender = new ArpSender(packetProcessingService);
 141             } else {
 142                 LOG.error("Missing service {}", PacketProcessingService.class.getSimpleName());
 143                 this.arpSender = null;
 144             }
 145             flowService = providerContext.getRpcService(SalFlowService.class);
 146             refreshRequester.scheduleWithFixedDelay(new Runnable(){
 147
 148                 @Override
 149                 public void run() {
 150                     if (!gatewayToArpMetadataMap.isEmpty()){
 151                         for(final Entry<Ipv4Address, ArpResolverMetadata> gatewayToArpMetadataEntry : gatewayToArpMetadataMap.entrySet()){
 152                             final Ipv4Address gatewayIp = gatewayToArpMetadataEntry.getKey();
 153                             final ArpResolverMetadata gatewayMetaData =
 154                                     checkAndGetExternalBridgeDpid(gatewayToArpMetadataEntry.getValue());
 155                             gatewayMacRefresherPool.schedule(new Runnable(){
 156
 157                                 @Override
 158                                 public void run() {
 159
 160                                     final Node externalNetworkBridge = getExternalBridge(gatewayMetaData.getExternalNetworkBridgeDpid());
 161                                     if(externalNetworkBridge == null){
 162                                         LOG.error("MAC address for gateway {} can not be resolved, because external bridge {} "
 163                                                 + "is not connected to controller.",
 164                                                 gatewayIp.getValue(),
 165                                                 gatewayMetaData.getExternalNetworkBridgeDpid() );
 166                                     } else {
 167                                         LOG.debug("Refresh Gateway Mac for gateway {} using source ip {} and mac {} for ARP request",
 168                                                 gatewayIp.getValue(),gatewayMetaData.getArpRequestSourceIp().getValue(),gatewayMetaData.getArpRequestSourceMacAddress().getValue());
 169
 170                                         sendGatewayArpRequest(externalNetworkBridge,gatewayIp,gatewayMetaData.getArpRequestSourceIp(), gatewayMetaData.getArpRequestSourceMacAddress());
 171                                     }
 172                                 }
 173                             }, 1, TimeUnit.SECONDS);
 174                         }
 175                     }
 176                 }
 177             }, REFRESH_INTERVAL, REFRESH_INTERVAL, TimeUnit.SECONDS);
 178         }
 179     }
 180     /**
 181      * Method do following actions:
 182      * 1. Install flow to direct ARP response packet to controller
 183      * 2. Send ARP request packet out on all port of the given External network bridge.
 184      * 3. Cache the flow that need to be removed once ARP resolution is done.
 185      * 4. Return listenable future so that user can add callback to get the MacAddress
 186      * @param externalNetworkBridgeDpid Broadcast ARP request packet on this bridge
 187      * @param gatewayIp IP address for which MAC need to be resolved
 188      * @param sourceIpAddress Source Ip address for the ARP request packet
 189      * @param sourceMacAddress Source Mac address for the ARP request packet
 190      * @param periodicRefresh Enable/Disable periodic refresh of the Gateway Mac address
 191      * @return Future object
 192      */
 193     @Override
 194     public ListenableFuture<MacAddress> resolveMacAddress(
 195             final GatewayMacResolverListener gatewayMacResolverListener, final Long externalNetworkBridgeDpid,
 196             final Boolean refreshExternalNetworkBridgeDpidIfNeeded,
 197             final Ipv4Address gatewayIp, final Ipv4Address sourceIpAddress, final MacAddress sourceMacAddress,
 198             final Boolean periodicRefresh){
 199         Preconditions.checkNotNull(refreshExternalNetworkBridgeDpidIfNeeded);
 200         Preconditions.checkNotNull(sourceIpAddress);
 201         Preconditions.checkNotNull(sourceMacAddress);
 202         Preconditions.checkNotNull(gatewayIp);
 203
 204         LOG.info("Trigger Mac resolution for gateway {}, using source ip {} and mac {}",
 205                 gatewayIp.getValue(),sourceIpAddress.getValue(),sourceMacAddress.getValue());
 206
 207         init();
 208         if(gatewayToArpMetadataMap.containsKey(gatewayIp)){
 209             if(gatewayToArpMetadataMap.get(gatewayIp).getGatewayMacAddress() != null){
 210                 return arpWatcherWall.submit(new Callable<MacAddress>(){
 211
 212                     @Override
 213                     public MacAddress call() throws Exception {
 214                         return gatewayToArpMetadataMap.get(gatewayIp).getGatewayMacAddress();
 215                     }
 216                 });
 217             }
 218         }else{
 219             gatewayToArpMetadataMap.put(gatewayIp,new ArpResolverMetadata(gatewayMacResolverListener,
 220                     externalNetworkBridgeDpid, refreshExternalNetworkBridgeDpidIfNeeded,
 221                     gatewayIp, sourceIpAddress, sourceMacAddress, periodicRefresh));
 222         }
 223
 224
 225         final Node externalNetworkBridge = getExternalBridge(externalNetworkBridgeDpid);
 226         if (externalNetworkBridge == null) {
 227             if (!refreshExternalNetworkBridgeDpidIfNeeded) {
 228                 LOG.error("MAC address for gateway {} can not be resolved, because external bridge {} "
 229                         + "is not connected to controller.", gatewayIp.getValue(), externalNetworkBridgeDpid);
 230             } else {
 231                 LOG.debug("MAC address for gateway {} can not be resolved, since dpid was not refreshed yet",
 232                         gatewayIp.getValue());
 233             }
 234             return null;
 235         }
 236
 237         sendGatewayArpRequest(externalNetworkBridge,gatewayIp,sourceIpAddress, sourceMacAddress);
 238
 239         //Wait for MacAddress population in cache
 240         return waitForMacAddress(gatewayIp);
 241     }
 242
 243     private Node getExternalBridge(final Long externalNetworkBridgeDpid){
 244         if (externalNetworkBridgeDpid != null) {
 245             final String nodeName = OPENFLOW + externalNetworkBridgeDpid;
 246             return getOpenFlowNode(nodeName);
 247         }
 248         return null;
 249     }
 250
 251     private ArpResolverMetadata checkAndGetExternalBridgeDpid(ArpResolverMetadata gatewayMetaData) {
 252         final Long origDpid = gatewayMetaData.getExternalNetworkBridgeDpid();
 253
 254         // If we are not allowing dpid to change, there is nothing further to do here
 255         if (!gatewayMetaData.isRefreshExternalNetworkBridgeDpidIfNeeded()) {
 256             return gatewayMetaData;
 257         }
 258
 259         // If current dpid is null, or if mac is not getting resolved, make an attempt to
 260         // grab a different dpid, so a different (or updated) external bridge gets used
 261         if (origDpid == null || !gatewayMetaData.isGatewayMacAddressResolved()) {
 262             Long newDpid = getAnotherExternalBridgeDpid(origDpid);
 263             gatewayMetaData.setExternalNetworkBridgeDpid(newDpid);
 264         }
 265
 266         return gatewayMetaData;
 267     }
 268
 269     private Long getAnotherExternalBridgeDpid(final Long unwantedDpid) {
 270         LOG.trace("Being asked to find a new dpid. unwantedDpid:{} cachemanager:{} configurationService:{}",
 271                 unwantedDpid, nodeCacheManager, configurationService);
 272
 273         if (nodeCacheManager == null) {
 274             LOG.error("Unable to find external dpid to use for resolver: no nodeCacheManager");
 275             return unwantedDpid;
 276         }
 277         if (configurationService == null) {
 278             LOG.error("Unable to find external dpid to use for resolver: no configurationService");
 279             return unwantedDpid;
 280         }
 281
 282         // Pickup another dpid in list that is different than the unwanted one provided and is in the
 283         // operational tree. If none can be found, return the provided dpid as a last resort.
 284         // NOTE: We are assuming that all the br-ex are serving one external network and gateway ip of
 285         // the external network is reachable from every br-ex
 286         // TODO: Consider other deployment scenario, and think of another solution.
 287         List<Long> dpids =  nodeCacheManager.getBridgeDpids(configurationService.getExternalBridgeName());
 288         Collections.shuffle(dpids);
 289         for (Long dpid : dpids) {
 290             if (dpid == null || dpid.equals(unwantedDpid) || getExternalBridge(dpid) == null) {
 291                 continue;
 292             }
 293
 294             LOG.debug("Gateway Mac Resolver Service will use dpid {}", dpid);
 295             return dpid;
 296         }
 297
 298         LOG.warn("Unable to find usable external dpid for resolver. Best choice is still {}", unwantedDpid);
 299         return unwantedDpid;
 300     }
 301
 302     private void sendGatewayArpRequest(final Node externalNetworkBridge,final Ipv4Address gatewayIp,
 303             final Ipv4Address sourceIpAddress, final MacAddress sourceMacAddress){
 304         final ArpMessageAddress senderAddress = new ArpMessageAddress(sourceMacAddress,sourceIpAddress);
 305
 306         //Build arp reply router flow
 307         final Flow arpReplyToControllerFlow = createArpReplyToControllerFlow(senderAddress, gatewayIp);
 308
 309         final InstanceIdentifier<Node> nodeIid = InstanceIdentifier.builder(Nodes.class)
 310                 .child(Node.class, externalNetworkBridge.getKey())
 311                 .build();
 312         final InstanceIdentifier<Flow> flowIid = createFlowIid(arpReplyToControllerFlow, nodeIid);
 313         final NodeRef nodeRef = new NodeRef(nodeIid);
 314
 315         //Install flow
 316         Future<RpcResult<AddFlowOutput>> addFlowResult = flowService.addFlow(new AddFlowInputBuilder(
 317                 arpReplyToControllerFlow).setFlowRef(new FlowRef(flowIid)).setNode(nodeRef).build());
 318         //wait for flow installation
 319         Futures.addCallback(JdkFutureAdapters.listenInPoolThread(addFlowResult),
 320                 new FutureCallback<RpcResult<AddFlowOutput>>() {
 321
 322             @Override
 323             public void onSuccess(RpcResult<AddFlowOutput> result) {
 324                 if (!result.isSuccessful()) {
 325                     LOG.warn("Flow to route ARP Reply to Controller is not installed successfully : {} \nErrors: {}", flowIid,result.getErrors());
 326                     return;
 327                 }
 328                 LOG.debug("Flow to route ARP Reply to Controller installed successfully : {}", flowIid);
 329
 330                 ArpResolverMetadata gatewayArpMetadata = gatewayToArpMetadataMap.get(gatewayIp);
 331                 if (gatewayArpMetadata == null) {
 332                     LOG.warn("No metadata found for gatewayIp: {}", gatewayIp);
 333                     return;
 334                 }
 335
 336                 //cache metadata
 337                 gatewayArpMetadata.setFlowToRemove(new RemoveFlowInputBuilder(arpReplyToControllerFlow).setNode(nodeRef).build());
 338
 339                 //get MAC DA for ARP packets
 340                 MacAddress arpRequestDestMacAddress = gatewayArpMetadata.getArpRequestDestMacAddress();
 341
 342                 //Send ARP request packets
 343                 for (NodeConnector egressNc : externalNetworkBridge.getNodeConnector()) {
 344                     KeyedInstanceIdentifier<NodeConnector, NodeConnectorKey> egressNcIid = nodeIid.child(
 345                             NodeConnector.class, new NodeConnectorKey(egressNc.getId()));
 346                     ListenableFuture<RpcResult<Void>> futureSendArpResult = arpSender.sendArp(
 347                             senderAddress, gatewayIp, arpRequestDestMacAddress, egressNcIid);
 348                     Futures.addCallback(futureSendArpResult, logResult(gatewayIp, egressNcIid));
 349                 }
 350             }
 351
 352             @Override
 353             public void onFailure(Throwable t) {
 354                 LOG.warn("ARP Reply to Controller flow was not created: {}", flowIid, t);
 355             }
 356             }
 357         );
 358     }
 359
 360     private ListenableFuture<MacAddress> waitForMacAddress(final Ipv4Address gatewayIp){
 361
 362         return arpWatcherWall.submit(new Callable<MacAddress>(){
 363
 364             @Override
 365             public MacAddress call() throws Exception {
 366                 for(int cycle = 0;cycle < WAIT_CYCLES;cycle++){
 367                     //Sleep before checking mac address, so meanwhile ARP request packets
 368                     // will be broadcasted on the bridge.
 369                     Thread.sleep(PER_CYCLE_WAIT_DURATION);
 370                     ArpResolverMetadata arpResolverMetadata = gatewayToArpMetadataMap.get(gatewayIp);
 371                     if(arpResolverMetadata != null && arpResolverMetadata.getGatewayMacAddress() != null){
 372                         if(!arpResolverMetadata.isPeriodicRefresh()){
 373                             return gatewayToArpMetadataMap.remove(gatewayIp).getGatewayMacAddress();
 374                         }
 375                         return arpResolverMetadata.getGatewayMacAddress();
 376                     }
 377                 }
 378                 return null;
 379             }
 380         });
 381     }
 382
 383     private Flow createArpReplyToControllerFlow(final ArpMessageAddress senderAddress, final Ipv4Address ipForRequestedMac) {
 384         checkNotNull(senderAddress);
 385         checkNotNull(ipForRequestedMac);
 386         FlowBuilder arpFlow = new FlowBuilder().setTableId(TABLE_FOR_ARP_FLOW)
 387             .setFlowName(ARP_REPLY_TO_CONTROLLER_FLOW_NAME)
 388             .setPriority(ARP_REPLY_TO_CONTROLLER_FLOW_PRIORITY)
 389             .setBufferId(OFConstants.OFP_NO_BUFFER)
 390             .setIdleTimeout(0)
 391             .setHardTimeout(0)
 392             .setCookie(new FlowCookie(BigInteger.valueOf(flowCookie.incrementAndGet())))
 393             .setFlags(new FlowModFlags(false, false, false, false, false));
 394
 395         EthernetMatch ethernetMatch = ArpFlowFactory.createEthernetMatch(senderAddress.getHardwareAddress());
 396         ArpMatch arpMatch = ArpFlowFactory.createArpMatch(senderAddress, ipForRequestedMac);
 397         Match match = new MatchBuilder().setEthernetMatch(ethernetMatch).setLayer3Match(arpMatch).build();
 398         arpFlow.setMatch(match);
 399         arpFlow.setInstructions(new InstructionsBuilder().setInstruction(
 400                 ImmutableList.of(SEND_TO_CONTROLLER_INSTRUCTION)).build());
 401         arpFlow.setId(createFlowId(ipForRequestedMac));
 402         return arpFlow.build();
 403     }
 404
 405     private FlowId createFlowId(Ipv4Address ipForRequestedMac) {
 406         String flowId = ARP_REPLY_TO_CONTROLLER_FLOW_NAME + "|" + ipForRequestedMac.getValue();
 407         return new FlowId(flowId);
 408     }
 409
 410     private static InstanceIdentifier<Flow> createFlowIid(Flow flow, InstanceIdentifier<Node> nodeIid) {
 411         return nodeIid.builder()
 412             .augmentation(FlowCapableNode.class)
 413             .child(Table.class, new TableKey(flow.getTableId()))
 414             .child(Flow.class, new FlowKey(flow.getId()))
 415             .build();
 416     }
 417
 418     private FutureCallback<RpcResult<Void>> logResult(final Ipv4Address tpa,
 419             final KeyedInstanceIdentifier<NodeConnector, NodeConnectorKey> egressNcIid) {
 420         return new FutureCallback<RpcResult<Void>>() {
 421
 422             @Override
 423             public void onSuccess(RpcResult<Void> result) {
 424                 LOG.debug("ARP Request for IP {} was sent from {}.", tpa.getValue(), egressNcIid);
 425             }
 426
 427             @Override
 428             public void onFailure(Throwable t) {
 429                 LOG.warn("ARP Request for IP {} was NOT sent from {}.", tpa.getValue(), egressNcIid);
 430             }
 431         };
 432     }
 433
 434     @Override
 435     public void onPacketReceived(PacketReceived potentialArp) {
 436         Arp arp = ArpResolverUtils.getArpFrom(potentialArp);
 437         if(arp != null){
 438             if (arp.getOperation() != ArpOperation.REPLY.intValue()) {
 439                 LOG.trace("Packet is not ARP REPLY packet.");
 440                 return;
 441             }
 442             if (LOG.isTraceEnabled()) {
 443                 LOG.trace("ARP REPLY received - {}", ArpUtils.getArpToStringFormat(arp));
 444             }
 445             NodeKey nodeKey = potentialArp.getIngress().getValue().firstKeyOf(Node.class, NodeKey.class);
 446             if (nodeKey == null) {
 447                 LOG.info("Unknown source node of ARP packet: {}", potentialArp);
 448                 return;
 449             }
 450             Ipv4Address gatewayIpAddress = ArpUtils.bytesToIp(arp.getSenderProtocolAddress());
 451             MacAddress gatewayMacAddress = ArpUtils.bytesToMac(arp.getSenderHardwareAddress());
 452             ArpResolverMetadata candidateGatewayIp = gatewayToArpMetadataMap.get(gatewayIpAddress);
 453             if(candidateGatewayIp != null){
 454                 LOG.debug("Resolved MAC for Gateway Ip {} is {}",gatewayIpAddress.getValue(),gatewayMacAddress.getValue());
 455                 candidateGatewayIp.setGatewayMacAddress(gatewayMacAddress);
 456                 flowService.removeFlow(candidateGatewayIp.getFlowToRemove());
 457             }
 458         }
 459     }
 460
 461     @Override
 462     public void setDependencies(BundleContext bundleContext,
 463             ServiceReference serviceReference) {
 464         super.setDependencies(bundleContext.getServiceReference(GatewayMacResolver.class.getName()), this);
 465
 466     }
 467
 468     @Override
 469     public void setDependencies(Object impl) {
 470         if (impl instanceof NodeCacheManager) {
 471             nodeCacheManager = (NodeCacheManager) impl;
 472         } else if (impl instanceof ConfigurationService) {
 473             configurationService = (ConfigurationService) impl;
 474         }
 475     }
 476
 477     @Override
 478     public void stopPeriodicRefresh(Ipv4Address gatewayIp) {
 479         init();
 480         gatewayToArpMetadataMap.remove(gatewayIp);
 481     }
 482
 483 }