Stale MIP FIB/Flow entries present upon deletion of VRRP master
[netvirt.git] / vpnmanager / impl / src / main / java / org / opendaylight / netvirt / vpnmanager / VpnUtil.java
index 856d02eff739dc3429ffa9d27cf7c2698bcb1e34..2c47b7e560a68590faf3917f92e92e380dcc6937 100644 (file)
@@ -9,7 +9,6 @@
 package org.opendaylight.netvirt.vpnmanager;
 
 import static java.util.Collections.emptyList;
-import static java.util.Objects.requireNonNull;
 import static org.opendaylight.genius.infra.Datastore.OPERATIONAL;
 
 import com.google.common.base.Optional;
@@ -37,11 +36,12 @@ import java.util.Objects;
 import java.util.Set;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.Future;
+import java.util.concurrent.locks.ReentrantLock;
 import java.util.function.Predicate;
 import java.util.stream.Collectors;
-import javax.annotation.Nonnull;
-import javax.annotation.Nullable;
 import javax.inject.Singleton;
+import org.eclipse.jdt.annotation.NonNull;
+import org.eclipse.jdt.annotation.Nullable;
 import org.opendaylight.controller.md.sal.binding.api.DataBroker;
 import org.opendaylight.controller.md.sal.binding.api.WriteTransaction;
 import org.opendaylight.controller.md.sal.common.api.data.LogicalDatastoreType;
@@ -72,6 +72,7 @@ import org.opendaylight.genius.mdsalutil.interfaces.IMdsalApiManager;
 import org.opendaylight.genius.mdsalutil.matches.MatchEthernetDestination;
 import org.opendaylight.genius.mdsalutil.matches.MatchEthernetType;
 import org.opendaylight.genius.mdsalutil.matches.MatchMetadata;
+import org.opendaylight.genius.utils.JvmGlobalLocks;
 import org.opendaylight.genius.utils.ServiceIndex;
 import org.opendaylight.genius.utils.SystemPropertyReader;
 import org.opendaylight.infrautils.jobcoordinator.JobCoordinator;
@@ -86,15 +87,6 @@ import org.opendaylight.netvirt.vpnmanager.api.InterfaceUtils;
 import org.opendaylight.netvirt.vpnmanager.api.VpnExtraRouteHelper;
 import org.opendaylight.netvirt.vpnmanager.api.VpnHelper;
 import org.opendaylight.netvirt.vpnmanager.iplearn.model.MacEntry;
-import org.opendaylight.yang.gen.v1.urn.huawei.params.xml.ns.yang.l3vpn.rev140815.VpnAfConfig;
-import org.opendaylight.yang.gen.v1.urn.huawei.params.xml.ns.yang.l3vpn.rev140815.VpnInstances;
-import org.opendaylight.yang.gen.v1.urn.huawei.params.xml.ns.yang.l3vpn.rev140815.VpnInterfaces;
-import org.opendaylight.yang.gen.v1.urn.huawei.params.xml.ns.yang.l3vpn.rev140815.vpn.instances.VpnInstance;
-import org.opendaylight.yang.gen.v1.urn.huawei.params.xml.ns.yang.l3vpn.rev140815.vpn.instances.VpnInstanceKey;
-import org.opendaylight.yang.gen.v1.urn.huawei.params.xml.ns.yang.l3vpn.rev140815.vpn.interfaces.VpnInterface;
-import org.opendaylight.yang.gen.v1.urn.huawei.params.xml.ns.yang.l3vpn.rev140815.vpn.interfaces.VpnInterfaceBuilder;
-import org.opendaylight.yang.gen.v1.urn.huawei.params.xml.ns.yang.l3vpn.rev140815.vpn.interfaces.VpnInterfaceKey;
-import org.opendaylight.yang.gen.v1.urn.huawei.params.xml.ns.yang.l3vpn.rev140815.vpn.interfaces.vpn._interface.VpnInstanceNames;
 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev130715.IpAddress;
 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev130715.IpAddressBuilder;
 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev130715.Ipv6Address;
@@ -154,12 +146,9 @@ import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.fibmanager.rev15033
 import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.fibmanager.rev150330.fibentries.VrfTablesKey;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.fibmanager.rev150330.vrfentries.VrfEntry;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.fibmanager.rev150330.vrfentries.VrfEntryKey;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.fibmanager.rev150330.vrfentrybase.RoutePaths;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.l3nexthop.rev150409.L3nexthop;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.l3nexthop.rev150409.l3nexthop.VpnNexthops;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.l3nexthop.rev150409.l3nexthop.VpnNexthopsKey;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.l3vpn.rev130911.Adjacencies;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.l3vpn.rev130911.AdjacenciesBuilder;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.l3vpn.rev130911.AdjacenciesOp;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.l3vpn.rev130911.AdjacenciesOpBuilder;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.l3vpn.rev130911.LearntVpnVipToPortData;
@@ -172,8 +161,6 @@ import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.l3vpn.rev130911.Vpn
 import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.l3vpn.rev130911.VpnInstanceOpData;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.l3vpn.rev130911.VpnInterfaceOpData;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.l3vpn.rev130911.VpnToExtraroutes;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.l3vpn.rev130911.adjacency.list.Adjacency;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.l3vpn.rev130911.adjacency.list.AdjacencyKey;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.l3vpn.rev130911.learnt.vpn.vip.to.port.data.LearntVpnVipToPort;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.l3vpn.rev130911.learnt.vpn.vip.to.port.data.LearntVpnVipToPortBuilder;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.l3vpn.rev130911.learnt.vpn.vip.to.port.data.LearntVpnVipToPortKey;
@@ -220,6 +207,19 @@ import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.natservice.rev16011
 import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.natservice.rev160111.external.subnets.SubnetsKey;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.natservice.rev160111.napt.switches.RouterToNaptSwitch;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.natservice.rev160111.napt.switches.RouterToNaptSwitchKey;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.neutronvpn.l3vpn.rev200204.Adjacencies;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.neutronvpn.l3vpn.rev200204.AdjacenciesBuilder;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.neutronvpn.l3vpn.rev200204.VpnInstances;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.neutronvpn.l3vpn.rev200204.VpnInterfaces;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.neutronvpn.l3vpn.rev200204.adjacency.list.Adjacency;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.neutronvpn.l3vpn.rev200204.adjacency.list.Adjacency.AdjacencyType;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.neutronvpn.l3vpn.rev200204.adjacency.list.AdjacencyKey;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.neutronvpn.l3vpn.rev200204.vpn.instances.VpnInstance;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.neutronvpn.l3vpn.rev200204.vpn.instances.VpnInstanceKey;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.neutronvpn.l3vpn.rev200204.vpn.interfaces.VpnInterface;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.neutronvpn.l3vpn.rev200204.vpn.interfaces.VpnInterfaceBuilder;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.neutronvpn.l3vpn.rev200204.vpn.interfaces.VpnInterfaceKey;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.neutronvpn.l3vpn.rev200204.vpn.interfaces.vpn._interface.VpnInstanceNames;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.neutronvpn.rev150602.NetworkAttributes.NetworkType;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.neutronvpn.rev150602.NetworkMaps;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.neutronvpn.rev150602.NeutronVpnPortipPortData;
@@ -245,6 +245,8 @@ import org.opendaylight.yang.gen.v1.urn.opendaylight.neutron.subnets.rev150712.s
 import org.opendaylight.yangtools.yang.binding.DataObject;
 import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
 import org.opendaylight.yangtools.yang.common.RpcResult;
+import org.opendaylight.yangtools.yang.common.Uint32;
+import org.opendaylight.yangtools.yang.common.Uint64;
 import org.opendaylight.yangtools.yang.data.api.schema.tree.ModifiedNodeDoesNotExistException;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -334,11 +336,11 @@ public final class VpnUtil {
     }
 
     static VpnInterfaceOpDataEntry getVpnInterfaceOpDataEntry(String intfName, String vpnName, AdjacenciesOp aug,
-                                                       BigInteger dpnId, long lportTag,
-                                                       String gwMac) {
+                                                              Uint64 dpnId, long lportTag,
+                                                              String gwMac, String gwIp) {
         return new VpnInterfaceOpDataEntryBuilder().withKey(new VpnInterfaceOpDataEntryKey(intfName, vpnName))
-            .setDpnId(dpnId).addAugmentation(AdjacenciesOp.class, aug)
-                .setLportTag(lportTag).setGatewayMacAddress(gwMac).build();
+                .setDpnId(dpnId).addAugmentation(AdjacenciesOp.class, aug)
+                .setLportTag(lportTag).setGatewayMacAddress(gwMac).setGatewayIpAddress(gwIp).build();
     }
 
     Optional<VpnInterfaceOpDataEntry> getVpnInterfaceOpDataEntry(String vpnInterfaceName, String vpnName) {
@@ -349,16 +351,16 @@ public final class VpnUtil {
         return vpnInterfaceOpDataEntry;
     }
 
-    static InstanceIdentifier<Prefixes> getPrefixToInterfaceIdentifier(long vpnId, String ipPrefix) {
+    static InstanceIdentifier<Prefixes> getPrefixToInterfaceIdentifier(Uint32 vpnId, String ipPrefix) {
         return InstanceIdentifier.builder(PrefixToInterface.class).child(VpnIds.class, new VpnIdsKey(vpnId))
                 .child(Prefixes.class, new PrefixesKey(ipPrefix)).build();
     }
 
-    static InstanceIdentifier<VpnIds> getPrefixToInterfaceIdentifier(long vpnId) {
+    static InstanceIdentifier<VpnIds> getPrefixToInterfaceIdentifier(Uint32 vpnId) {
         return InstanceIdentifier.builder(PrefixToInterface.class).child(VpnIds.class, new VpnIdsKey(vpnId)).build();
     }
 
-    static Prefixes getPrefixToInterface(BigInteger dpId, String vpnInterfaceName, String ipPrefix,
+    static Prefixes getPrefixToInterface(Uint64 dpId, String vpnInterfaceName, String ipPrefix,
             Uuid networkId, NetworkType networkType, Long segmentationId, Prefixes.PrefixCue prefixCue) {
         return new PrefixesBuilder().setDpnId(dpId).setVpnInterfaceName(
             vpnInterfaceName).setIpAddress(ipPrefix)//.setSubnetId(subnetId)
@@ -366,13 +368,13 @@ public final class VpnUtil {
                 .setPrefixCue(prefixCue).build();
     }
 
-    static Prefixes getPrefixToInterface(BigInteger dpId, String vpnInterfaceName, String ipPrefix,
+    static Prefixes getPrefixToInterface(Uint64 dpId, String vpnInterfaceName, String ipPrefix,
             Prefixes.PrefixCue prefixCue) {
         return new PrefixesBuilder().setDpnId(dpId).setVpnInterfaceName(vpnInterfaceName).setIpAddress(ipPrefix)
                 .setPrefixCue(prefixCue).build();
     }
 
-    Optional<Prefixes> getPrefixToInterface(long vpnId, String ipPrefix) {
+    Optional<Prefixes> getPrefixToInterface(Uint32 vpnId, String ipPrefix) {
         return read(LogicalDatastoreType.OPERATIONAL, getPrefixToInterfaceIdentifier(vpnId, getIpPrefix(ipPrefix)));
     }
 
@@ -433,20 +435,26 @@ public final class VpnUtil {
         return vpnInstance.isPresent() ? vpnInstance.get() : null;
     }
 
-    @Nonnull
+    @NonNull
+    @SuppressWarnings("checkstyle:IllegalCatch")
     List<VpnInstanceOpDataEntry> getAllVpnInstanceOpData() {
-        InstanceIdentifier<VpnInstanceOpData> id = InstanceIdentifier.builder(VpnInstanceOpData.class).build();
-        Optional<VpnInstanceOpData> vpnInstanceOpDataOptional = read(LogicalDatastoreType.OPERATIONAL, id);
-        return
-            vpnInstanceOpDataOptional.isPresent() && vpnInstanceOpDataOptional.get().getVpnInstanceOpDataEntry() != null
-                ? vpnInstanceOpDataOptional.get().getVpnInstanceOpDataEntry()
-                : emptyList();
+        try {
+            InstanceIdentifier<VpnInstanceOpData> id = InstanceIdentifier.builder(VpnInstanceOpData.class).build();
+            Optional<VpnInstanceOpData> vpnInstanceOpDataOptional = read(LogicalDatastoreType.OPERATIONAL, id);
+            return
+                    vpnInstanceOpDataOptional.isPresent() && vpnInstanceOpDataOptional.get()
+                            .getVpnInstanceOpDataEntry() != null ? vpnInstanceOpDataOptional.get()
+                            .getVpnInstanceOpDataEntry() : emptyList();
+        } catch (Exception e) {
+            LOG.error("getAllVpnInstanceOpData: Could not retrieve all vpn instance op data subtree...", e);
+            return emptyList();
+        }
     }
 
-    @Nonnull
+    @NonNull
     List<org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.l3vpn.rev130911.vpn.instance.op.data
             .vpn.instance.op.data.entry.vpn.to.dpn.list.VpnInterfaces> getDpnVpnInterfaces(VpnInstance vpnInstance,
-                                                                                           BigInteger dpnId) {
+                                                                                           Uint64 dpnId) {
         String primaryRd = getPrimaryRd(vpnInstance);
         InstanceIdentifier<VpnToDpnList> dpnToVpnId = VpnHelper.getVpnToDpnListIdentifier(primaryRd, dpnId);
         Optional<VpnToDpnList> dpnInVpn = read(LogicalDatastoreType.OPERATIONAL, dpnToVpnId);
@@ -454,12 +462,10 @@ public final class VpnUtil {
             : emptyList();
     }
 
-    @Nonnull
+    @NonNull
     static List<String> getListOfRdsFromVpnInstance(VpnInstance vpnInstance) {
-        VpnAfConfig vpnConfig = vpnInstance.getIpv4Family();
-        LOG.trace("vpnConfig {}", vpnConfig);
-        return vpnConfig.getRouteDistinguisher() != null && vpnConfig.getRouteDistinguisher() != null
-            ? vpnConfig.getRouteDistinguisher() : emptyList();
+        return vpnInstance.getRouteDistinguisher() != null ? new ArrayList<>(
+                vpnInstance.getRouteDistinguisher()) : new ArrayList<>();
     }
 
     @Nullable
@@ -494,9 +500,9 @@ public final class VpnUtil {
     }
 
     @Nullable
-    String getVpnInterfaceName(BigInteger metadata) throws InterruptedException, ExecutionException {
+    String getVpnInterfaceName(Uint64 metadata) throws InterruptedException, ExecutionException {
         GetInterfaceFromIfIndexInputBuilder ifIndexInputBuilder = new GetInterfaceFromIfIndexInputBuilder();
-        BigInteger lportTag = MetaDataUtil.getLportFromMetadata(metadata);
+        Uint64 lportTag = MetaDataUtil.getLportFromMetadata(metadata);
         ifIndexInputBuilder.setIfIndex(lportTag.intValue());
         GetInterfaceFromIfIndexInput input = ifIndexInputBuilder.build();
         Future<RpcResult<GetInterfaceFromIfIndexOutput>> interfaceFromIfIndex =
@@ -527,17 +533,18 @@ public final class VpnUtil {
                 new InterfaceKey(interfaceName)).build();
     }
 
-    public static BigInteger getCookieL3(int vpnId) {
-        return VpnConstants.COOKIE_L3_BASE.add(new BigInteger("0610000", 16)).add(BigInteger.valueOf(vpnId));
+    public static Uint64 getCookieL3(int vpnId) {
+        return Uint64.valueOf(VpnConstants.COOKIE_L3_BASE.toJava().add(new BigInteger("0610000", 16))
+                .add(BigInteger.valueOf(vpnId)));
     }
 
-    public int getUniqueId(String poolName, String idKey) {
+    public Uint32 getUniqueId(String poolName, String idKey) {
         AllocateIdInput getIdInput = new AllocateIdInputBuilder().setPoolName(poolName).setIdKey(idKey).build();
         try {
             Future<RpcResult<AllocateIdOutput>> result = idManager.allocateId(getIdInput);
             RpcResult<AllocateIdOutput> rpcResult = result.get();
             if (rpcResult.isSuccessful()) {
-                return rpcResult.getResult().getIdValue().intValue();
+                return rpcResult.getResult().getIdValue();
             } else {
                 LOG.error("getUniqueId: RPC Call to Get Unique Id from pool {} with key {} returned with Errors {}",
                         poolName, idKey, rpcResult.getErrors());
@@ -545,7 +552,7 @@ public final class VpnUtil {
         } catch (InterruptedException | ExecutionException e) {
             LOG.error("getUniqueId: Exception when getting Unique Id from pool {} for key {}", poolName, idKey, e);
         }
-        return 0;
+        return Uint32.ZERO;
     }
 
     void releaseId(String poolName, String idKey) {
@@ -572,14 +579,15 @@ public final class VpnUtil {
      * @param vpnName Name of the VPN
      * @return the dataplane identifier of the VPN, the VrfTag.
      */
-    public long getVpnId(String vpnName) {
+    public Uint32 getVpnId(String vpnName) {
         if (vpnName == null) {
             return VpnConstants.INVALID_ID;
         }
 
         return read(LogicalDatastoreType.CONFIGURATION, VpnOperDsUtils.getVpnInstanceToVpnIdIdentifier(vpnName))
                 .toJavaUtil().map(org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.l3vpn.rev130911
-                        .vpn.instance.to.vpn.id.VpnInstance::getVpnId).orElse(VpnConstants.INVALID_ID);
+                        .vpn.instance.to.vpn.id.VpnInstance::getVpnId)
+                        .orElse(VpnConstants.INVALID_ID);
     }
 
     /**
@@ -630,8 +638,7 @@ public final class VpnUtil {
             ListenableFutures.addErrorLogging(
                     new ManagedNewTransactionRunnerImpl(dataBroker).callWithNewWriteOnlyTransactionAndSubmit(
                                                                             Datastore.CONFIGURATION, tx -> {
-                            for (VrfEntry vrfEntry : requireNonNullElse(vrfTables.getVrfEntry(),
-                                    Collections.<VrfEntry>emptyList())) {
+                            for (VrfEntry vrfEntry : vrfTables.nonnullVrfEntry()) {
                                 if (origin == RouteOrigin.value(vrfEntry.getOrigin())) {
                                     tx.delete(vpnVrfTableIid.child(VrfEntry.class, vrfEntry.key()));
                                 }
@@ -647,8 +654,8 @@ public final class VpnUtil {
         List<VrfEntry> matches = new ArrayList<>();
         if (vrfTablesOpc.isPresent()) {
             VrfTables vrfTables = vrfTablesOpc.get();
-            for (VrfEntry vrfEntry : requireNonNullElse(vrfTables.getVrfEntry(), Collections.<VrfEntry>emptyList())) {
-                requireNonNullElse(vrfEntry.getRoutePaths(), Collections.<RoutePaths>emptyList()).stream()
+            for (VrfEntry vrfEntry : vrfTables.nonnullVrfEntry()) {
+                vrfEntry.nonnullRoutePaths().stream()
                         .filter(routePath -> routePath.getNexthopAddress() != null && routePath.getNexthopAddress()
                                 .equals(nexthop)).findFirst().ifPresent(routePath -> matches.add(vrfEntry));
             }
@@ -701,7 +708,7 @@ public final class VpnUtil {
                 MDSALUtil.syncDelete(dataBroker,
                         LogicalDatastoreType.CONFIGURATION, VpnExtraRouteHelper.getUsedRdsIdentifier(getVpnId(vpnName),
                                 prefix, nextHop));
-                LOG.debug("removeOrUpdateDSForExtraRoute: Removed vpn-to-extraroute with rd {} prefix {} nexthop {}",
+                LOG.info("removeOrUpdateDSForExtraRoute: Removed vpn-to-extraroute with rd {} prefix {} nexthop {}",
                         extraRouteRd, prefix, nextHop);
                 fibManager.refreshVrfEntry(primaryRd, prefix);
                 operTx.delete(VpnUtil.getVpnInterfaceOpDataEntryAdjacencyIdentifier(vpnInterfaceName, vpnName, prefix));
@@ -714,13 +721,13 @@ public final class VpnUtil {
     }
 
     static org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.l3vpn.rev130911.vpn.instance.to.vpn.id.VpnInstance
-        getVpnInstanceToVpnId(String vpnName, long vpnId, String rd) {
+        getVpnInstanceToVpnId(String vpnName, Uint32 vpnId, String rd) {
         return new VpnInstanceBuilder().setVpnId(vpnId).setVpnInstanceName(vpnName).setVrfId(rd).build();
 
     }
 
     static org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.l3vpn.rev130911.vpn.id.to.vpn.instance.VpnIds
-        getVpnIdToVpnInstance(long vpnId, String vpnName, String rd, boolean isExternalVpn) {
+        getVpnIdToVpnInstance(Uint32 vpnId, String vpnName, String rd, boolean isExternalVpn) {
         return new org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.l3vpn.rev130911.vpn.id.to.vpn.instance
             .VpnIdsBuilder().setVpnId(vpnId).setVpnInstanceName(vpnName).setVrfId(rd).setExternalVpn(isExternalVpn)
                 .build();
@@ -728,7 +735,7 @@ public final class VpnUtil {
     }
 
     static InstanceIdentifier<org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.l3vpn.rev130911.vpn.id.to
-        .vpn.instance.VpnIds> getVpnIdToVpnInstanceIdentifier(long vpnId) {
+        .vpn.instance.VpnIds> getVpnIdToVpnInstanceIdentifier(Uint32 vpnId) {
         return InstanceIdentifier.builder(VpnIdToVpnInstance.class).child(org.opendaylight.yang.gen.v1.urn
                 .opendaylight.netvirt.l3vpn.rev130911.vpn.id.to.vpn.instance.VpnIds.class,
                 new org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.l3vpn.rev130911.vpn.id.to.vpn.instance
@@ -742,7 +749,7 @@ public final class VpnUtil {
      * @return the Vpn instance name
      */
     @Nullable
-    String getVpnName(long vpnId) {
+    String getVpnName(Uint32 vpnId) {
 
         InstanceIdentifier<org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.l3vpn.rev130911.vpn.id.to.vpn
             .instance.VpnIds> id = getVpnIdToVpnInstanceIdentifier(vpnId);
@@ -884,38 +891,38 @@ public final class VpnUtil {
             new ElanTagNameKey(elanTag)).build();
     }
 
-    static void removePrefixToInterfaceForVpnId(long vpnId, @Nonnull TypedWriteTransaction<Operational> operTx) {
+    static void removePrefixToInterfaceForVpnId(Uint32 vpnId, @NonNull TypedWriteTransaction<Operational> operTx) {
         // Clean up PrefixToInterface Operational DS
         operTx.delete(InstanceIdentifier.builder(
                     PrefixToInterface.class).child(VpnIds.class, new VpnIdsKey(vpnId)).build());
     }
 
-    static void removeVpnExtraRouteForVpn(String vpnName, @Nonnull TypedWriteTransaction<Operational> operTx) {
+    static void removeVpnExtraRouteForVpn(String vpnName, @NonNull TypedWriteTransaction<Operational> operTx) {
         // Clean up VPNExtraRoutes Operational DS
         operTx.delete(InstanceIdentifier.builder(VpnToExtraroutes.class).child(Vpn.class, new VpnKey(vpnName)).build());
     }
 
     @SuppressWarnings("checkstyle:IllegalCatch")
-    static void removeVpnOpInstance(String vpnName, @Nonnull TypedWriteTransaction<Operational> operTx) {
+    static void removeVpnOpInstance(String vpnName, @NonNull TypedWriteTransaction<Operational> operTx) {
         // Clean up VPNInstanceOpDataEntry
         operTx.delete(getVpnInstanceOpDataIdentifier(vpnName));
     }
 
-    static void removeVpnInstanceToVpnId(String vpnName, @Nonnull TypedWriteTransaction<Configuration> confTx) {
+    static void removeVpnInstanceToVpnId(String vpnName, @NonNull TypedWriteTransaction<Configuration> confTx) {
         confTx.delete(VpnOperDsUtils.getVpnInstanceToVpnIdIdentifier(vpnName));
     }
 
-    static void removeVpnIdToVpnInstance(long vpnId, @Nonnull TypedWriteTransaction<Configuration> confTx) {
+    static void removeVpnIdToVpnInstance(Uint32 vpnId, @NonNull TypedWriteTransaction<Configuration> confTx) {
         confTx.delete(getVpnIdToVpnInstanceIdentifier(vpnId));
     }
 
-    static void removeL3nexthopForVpnId(long vpnId, @Nonnull TypedWriteTransaction<Operational> operTx) {
+    static void removeL3nexthopForVpnId(Uint32 vpnId, @NonNull TypedWriteTransaction<Operational> operTx) {
         // Clean up L3NextHop Operational DS
         operTx.delete(InstanceIdentifier.builder(L3nexthop.class).child(
                                     VpnNexthops.class, new VpnNexthopsKey(vpnId)).build());
     }
 
-    void scheduleVpnInterfaceForRemoval(String interfaceName, BigInteger dpnId, String vpnInstanceName,
+    void scheduleVpnInterfaceForRemoval(String interfaceName, Uint64 dpnId, String vpnInstanceName,
                                         @Nullable TypedWriteTransaction<Operational> writeOperTxn) {
         InstanceIdentifier<VpnInterfaceOpDataEntry> interfaceId =
                 getVpnInterfaceOpDataEntryIdentifier(interfaceName, vpnInstanceName);
@@ -932,8 +939,10 @@ public final class VpnUtil {
 
     public void createLearntVpnVipToPort(String vpnName, String fixedIp, String portName, String macAddress,
             TypedWriteTransaction<Operational> writeOperTxn) {
-        synchronized ((vpnName + fixedIp).intern()) {
-            InstanceIdentifier<LearntVpnVipToPort> id = buildLearntVpnVipToPortIdentifier(vpnName, fixedIp);
+        final InstanceIdentifier<LearntVpnVipToPort> id = buildLearntVpnVipToPortIdentifier(vpnName, fixedIp);
+        final ReentrantLock lock = lockFor(vpnName, fixedIp);
+        lock.lock();
+        try {
             LearntVpnVipToPortBuilder builder =
                     new LearntVpnVipToPortBuilder().withKey(new LearntVpnVipToPortKey(fixedIp, vpnName)).setVpnName(
                             vpnName).setPortFixedip(fixedIp).setPortName(portName)
@@ -946,6 +955,8 @@ public final class VpnUtil {
             }
             LOG.debug("createLearntVpnVipToPort: ARP/NA learned for fixedIp: {}, vpn {}, interface {}, mac {},"
                     + " added to LearntVpnVipToPort DS", fixedIp, vpnName, portName, macAddress);
+        } finally {
+            lock.unlock();
         }
     }
 
@@ -955,10 +966,12 @@ public final class VpnUtil {
                 new LearntVpnVipToPortKey(fixedIp, vpnName)).build();
     }
 
-    void removeLearntVpnVipToPort(String vpnName, String fixedIp,
-                                  @Nullable TypedWriteTransaction<Operational> writeOperTxn) {
-        synchronized ((vpnName + fixedIp).intern()) {
-            InstanceIdentifier<LearntVpnVipToPort> id = buildLearntVpnVipToPortIdentifier(vpnName, fixedIp);
+    public void removeLearntVpnVipToPort(String vpnName, String fixedIp,
+                                         @Nullable TypedWriteTransaction<Operational> writeOperTxn) {
+        final InstanceIdentifier<LearntVpnVipToPort> id = buildLearntVpnVipToPortIdentifier(vpnName, fixedIp);
+        final ReentrantLock lock = lockFor(vpnName, fixedIp);
+        lock.lock();
+        try {
             if (writeOperTxn != null) {
                 writeOperTxn.delete(id);
             } else {
@@ -966,13 +979,17 @@ public final class VpnUtil {
             }
             LOG.debug("removeLearntVpnVipToPort: Deleted LearntVpnVipToPort entry for fixedIp: {}, vpn {}",
                 fixedIp, vpnName);
+        } finally {
+            lock.unlock();
         }
     }
 
-    protected static void removeVpnPortFixedIpToPort(DataBroker broker, String vpnName, String fixedIp,
+    public static void removeVpnPortFixedIpToPort(DataBroker broker, String vpnName, String fixedIp,
                                                      @Nullable TypedWriteTransaction<Configuration> writeConfigTxn) {
-        synchronized ((vpnName + fixedIp).intern()) {
-            InstanceIdentifier<VpnPortipToPort> id = buildVpnPortipToPortIdentifier(vpnName, fixedIp);
+        final InstanceIdentifier<VpnPortipToPort> id = buildVpnPortipToPortIdentifier(vpnName, fixedIp);
+        final ReentrantLock lock = lockFor(vpnName, fixedIp);
+        lock.lock();
+        try {
             if (writeConfigTxn != null) {
                 writeConfigTxn.delete(id);
             } else {
@@ -980,6 +997,8 @@ public final class VpnUtil {
             }
             LOG.debug("removeVpnPortFixedIpToPort: Deleted VpnPortipToPort entry for fixedIp: {}, vpn {}",
                 fixedIp, vpnName);
+        } finally {
+            lock.unlock();
         }
     }
 
@@ -1023,30 +1042,49 @@ public final class VpnUtil {
     // TODO Clean up the exception handling
     @SuppressWarnings("checkstyle:IllegalCatch")
     public void removeMipAdjAndLearntIp(String vpnName, String vpnInterface, String prefix) {
-        synchronized ((vpnName + prefix).intern()) {
-            try {
-                String ip = VpnUtil.getIpPrefix(prefix);
-                InstanceIdentifier<VpnInterfaceOpDataEntry> vpnInterfaceOpId = VpnUtil
-                        .getVpnInterfaceOpDataEntryIdentifier(vpnInterface, vpnName);
-                InstanceIdentifier<AdjacenciesOp> path = vpnInterfaceOpId.augmentation(AdjacenciesOp.class);
-                Optional<AdjacenciesOp> adjacenciesOp = read(LogicalDatastoreType.OPERATIONAL, path);
-                if (adjacenciesOp.isPresent()) {
-                    InstanceIdentifier<Adjacency> adjacencyIdentifier = InstanceIdentifier.builder(VpnInterfaces.class)
-                            .child(VpnInterface.class, new VpnInterfaceKey(vpnInterface))
-                            .augmentation(Adjacencies.class).child(Adjacency.class, new AdjacencyKey(ip)).build();
-                    MDSALUtil.syncDelete(dataBroker, LogicalDatastoreType.CONFIGURATION, adjacencyIdentifier);
-                    LOG.info("removeMipAdjAndLearntIp: Successfully Deleted Adjacency {} from interface {} vpn {}", ip,
-                            vpnInterface, vpnName);
-                }
-                InstanceIdentifier<LearntVpnVipToPort> id = buildLearntVpnVipToPortIdentifier(vpnName, prefix);
-                MDSALUtil.syncDelete(dataBroker, LogicalDatastoreType.OPERATIONAL, id);
-                LOG.info("removeMipAdjAndLearntIp: Delete learned ARP for fixedIp: {}, vpn {} removed from"
-                        + "VpnPortipToPort DS", prefix, vpnName);
-            } catch (Exception e) {
-                LOG.error("removeMipAdjAndLearntIp: Exception Deleting learned Ip: {} interface {} vpn {} from "
-                        + "LearntVpnPortipToPort DS", prefix, vpnInterface, vpnName, e);
+        final ReentrantLock lock = lockFor(vpnName, prefix);
+        lock.lock();
+        try {
+            String ip = VpnUtil.getIpPrefix(prefix);
+            InstanceIdentifier<VpnInterfaceOpDataEntry> vpnInterfaceOpId = VpnUtil
+                    .getVpnInterfaceOpDataEntryIdentifier(vpnInterface, vpnName);
+            InstanceIdentifier<AdjacenciesOp> path = vpnInterfaceOpId.augmentation(AdjacenciesOp.class);
+            Optional<AdjacenciesOp> adjacenciesOp = read(LogicalDatastoreType.OPERATIONAL, path);
+            if (adjacenciesOp.isPresent()) {
+                InstanceIdentifier<Adjacency> adjacencyIdentifier = InstanceIdentifier.builder(VpnInterfaces.class)
+                        .child(VpnInterface.class, new VpnInterfaceKey(vpnInterface))
+                        .augmentation(Adjacencies.class).child(Adjacency.class, new AdjacencyKey(ip)).build();
+                MDSALUtil.syncDelete(dataBroker, LogicalDatastoreType.CONFIGURATION, adjacencyIdentifier);
+                LOG.info("removeMipAdjAndLearntIp: Successfully Deleted Adjacency {} from interface {} vpn {}", ip,
+                    vpnInterface, vpnName);
             }
-            VpnUtil.removeVpnPortFixedIpToPort(dataBroker, vpnName, prefix, null);
+            InstanceIdentifier<LearntVpnVipToPort> id = buildLearntVpnVipToPortIdentifier(vpnName, prefix);
+            MDSALUtil.syncDelete(dataBroker, LogicalDatastoreType.OPERATIONAL, id);
+            LOG.info("removeMipAdjAndLearntIp: Delete learned ARP for fixedIp: {}, vpn {} removed from"
+                    + "VpnPortipToPort DS", prefix, vpnName);
+        } catch (Exception e) {
+            LOG.error("removeMipAdjAndLearntIp: Exception Deleting learned Ip: {} interface {} vpn {} from "
+                    + "LearntVpnPortipToPort DS", prefix, vpnInterface, vpnName, e);
+        } finally {
+            lock.unlock();
+        }
+        VpnUtil.removeVpnPortFixedIpToPort(dataBroker, vpnName, prefix, null);
+    }
+
+    public void removeMipAdjacency(String vpnName, String vpnInterface, String prefix,
+                                   TypedWriteTransaction<Configuration> writeConfigTxn) {
+        String ip = VpnUtil.getIpPrefix(prefix);
+        LOG.trace("Removing {} adjacency from Old VPN Interface {} ", ip, vpnInterface);
+        InstanceIdentifier<VpnInterface> vpnIfId = VpnUtil.getVpnInterfaceIdentifier(vpnInterface);
+        InstanceIdentifier<Adjacencies> path = vpnIfId.augmentation(Adjacencies.class);
+        //TODO: Remove synchronized?
+
+        Optional<Adjacencies> adjacencies = read(LogicalDatastoreType.OPERATIONAL, path);
+        if (adjacencies.isPresent()) {
+            InstanceIdentifier<Adjacency> adjacencyIdentifier = getAdjacencyIdentifier(vpnInterface, prefix);
+            writeConfigTxn.delete(adjacencyIdentifier);
+            LOG.error("removeMipAdjacency: Successfully Deleted Adjacency {} from interface {} vpn {}", ip,
+                    vpnInterface, vpnName);
         }
     }
 
@@ -1054,7 +1092,8 @@ public final class VpnUtil {
         String prefix = VpnUtil.getIpPrefix(ipAddress);
         InstanceIdentifier<Adjacency> adjacencyIdentifier = getAdjacencyIdentifier(vpnInterface, prefix);
         try {
-            SingleTransactionDataBroker.syncDelete(dataBroker, LogicalDatastoreType.CONFIGURATION, adjacencyIdentifier);
+            SingleTransactionDataBroker.syncDelete(dataBroker, LogicalDatastoreType.CONFIGURATION,
+                    adjacencyIdentifier);
         } catch (TransactionCommitFailedException e) {
             if (e.getCause() instanceof ModifiedNodeDoesNotExistException) {
                 LOG.debug("vpnInterface {} is already deleted. prefix={}", vpnInterface, prefix);
@@ -1110,9 +1149,9 @@ public final class VpnUtil {
         return null;
     }
 
-    @Nonnull
-    List<BigInteger> getDpnsOnVpn(String vpnInstanceName) {
-        List<BigInteger> result = new ArrayList<>();
+    @NonNull
+    List<Uint64> getDpnsOnVpn(String vpnInstanceName) {
+        List<Uint64> result = new ArrayList<>();
         String rd = getVpnRd(vpnInstanceName);
         if (rd == null) {
             LOG.debug("getDpnsOnVpn: Could not find Route-Distinguisher for VpnName={}", vpnInstanceName);
@@ -1152,9 +1191,8 @@ public final class VpnUtil {
 
         String routerName = null;
 
-        for (Routers routerData : requireNonNullElse(extRouterData.get().getRouters(),
-                Collections.<Routers>emptyList())) {
-            List<ExternalIps> externalIps = requireNonNullElse(routerData.getExternalIps(), emptyList());
+        for (Routers routerData : extRouterData.get().nonnullRouters()) {
+            List<ExternalIps> externalIps = routerData.nonnullExternalIps();
             for (ExternalIps externalIp : externalIps) {
                 if (Objects.equals(externalIp.getIpAddress(), extIp)) {
                     routerName = routerData.getRouterName();
@@ -1167,9 +1205,8 @@ public final class VpnUtil {
             return routerName;
         }
 
-        for (Routers routerData : requireNonNullElse(extRouterData.get().getRouters(),
-                Collections.<Routers>emptyList())) {
-            List<ExternalIps> externalIps = requireNonNullElse(routerData.getExternalIps(), emptyList());
+        for (Routers routerData : extRouterData.get().nonnullRouters()) {
+            List<ExternalIps> externalIps = routerData.nonnullExternalIps();
             for (ExternalIps externalIp : externalIps) {
                 Subnet neutronSubnet = neutronVpnService.getNeutronSubnet(externalIp.getSubnetId());
                 if (neutronSubnet == null) {
@@ -1192,21 +1229,23 @@ public final class VpnUtil {
         InstanceIdentifier<ExtRouters> extRouterInstanceIndentifier =
                 InstanceIdentifier.builder(ExtRouters.class).build();
         Optional<ExtRouters> extRouterData = read(LogicalDatastoreType.CONFIGURATION, extRouterInstanceIndentifier);
-        if (!extRouterData.isPresent()) {
+        if (!extRouterData.isPresent() || extRouterData.get().getRouters() == null) {
             return null;
         }
-        for (Routers routerData : requireNonNullElse(extRouterData.get().getRouters(),
-                Collections.<Routers>emptyList())) {
-            List<ExternalIps> externalIps = requireNonNullElse(routerData.getExternalIps(), emptyList());
-            for (ExternalIps externalIp : externalIps) {
-                Subnet neutronSubnet = neutronVpnService.getNeutronSubnet(externalIp.getSubnetId());
-                if (neutronSubnet == null) {
-                    LOG.warn("Failed to retrieve subnet {} referenced by router {}",
+        for (Routers routerData : extRouterData.get().getRouters()) {
+            List<ExternalIps> externalIps = routerData.getExternalIps();
+            if (externalIps != null) {
+                for (ExternalIps externalIp : externalIps) {
+                    Subnet neutronSubnet = neutronVpnService.getNeutronSubnet(externalIp.getSubnetId());
+                    if (neutronSubnet == null) {
+                        LOG.warn("Failed to retrieve subnet {} referenced by router {}",
                             externalIp.getSubnetId(), routerData);
-                    continue;
-                }
-                if (NWUtil.isIpAddressInRange(IpAddressBuilder.getDefaultInstance(extIp), neutronSubnet.getCidr())) {
-                    return neutronSubnet.getUuid().getValue();
+                        continue;
+                    }
+                    if (NWUtil.isIpAddressInRange(IpAddressBuilder.getDefaultInstance(extIp),
+                            neutronSubnet.getCidr())) {
+                        return neutronSubnet.getUuid().getValue();
+                    }
                 }
             }
         }
@@ -1231,7 +1270,7 @@ public final class VpnUtil {
         return extNetwork != null ? extNetwork.getVpnid() : null;
     }
 
-    @Nonnull
+    @NonNull
     public List<Uuid> getExternalNetworkRouterIds(Uuid networkId) {
         Networks extNetwork = getExternalNetwork(networkId);
         return extNetwork != null && extNetwork.getRouterIds() != null ? extNetwork.getRouterIds() : emptyList();
@@ -1257,15 +1296,16 @@ public final class VpnUtil {
         return InstanceIdentifier.create(Subnetmaps.class);
     }
 
-    FlowEntity buildL3vpnGatewayFlow(BigInteger dpId, String gwMacAddress, long vpnId,
-                                                   long subnetVpnId) {
+    FlowEntity buildL3vpnGatewayFlow(Uint64 dpId, String gwMacAddress, Uint32 vpnId,
+                                               Uint32 subnetVpnId) {
         List<MatchInfo> mkMatches = new ArrayList<>();
         Subnetmap smap = null;
-        mkMatches.add(new MatchMetadata(MetaDataUtil.getVpnIdMetadata(vpnId), MetaDataUtil.METADATA_MASK_VRFID));
+        mkMatches.add(new MatchMetadata(MetaDataUtil.getVpnIdMetadata(vpnId.longValue()),
+            MetaDataUtil.METADATA_MASK_VRFID));
         mkMatches.add(new MatchEthernetDestination(new MacAddress(gwMacAddress)));
         List<InstructionInfo> mkInstructions = new ArrayList<>();
         mkInstructions.add(new InstructionGotoTable(NwConstants.L3_FIB_TABLE));
-        if (subnetVpnId != VpnConstants.INVALID_ID) {
+        if (!VpnConstants.INVALID_ID.equals(subnetVpnId)) {
             String vpnName = getVpnName(subnetVpnId);
             if (vpnName != null) {
                 smap = getSubnetmapFromItsUuid(Uuid.getDefaultInstance(vpnName));
@@ -1278,23 +1318,26 @@ public final class VpnUtil {
                     }
                 }
             }
-            BigInteger subnetIdMetaData = MetaDataUtil.getVpnIdMetadata(subnetVpnId);
+            Uint64 subnetIdMetaData = MetaDataUtil.getVpnIdMetadata(subnetVpnId.longValue());
             mkInstructions.add(new InstructionWriteMetadata(subnetIdMetaData, MetaDataUtil.METADATA_MASK_VRFID));
         }
         String flowId = getL3VpnGatewayFlowRef(NwConstants.L3_GW_MAC_TABLE, dpId, vpnId, gwMacAddress, subnetVpnId);
         return MDSALUtil.buildFlowEntity(dpId, NwConstants.L3_GW_MAC_TABLE,
-                flowId, 20, flowId, 0, 0, NwConstants.COOKIE_L3_GW_MAC_TABLE, mkMatches, mkInstructions);
+                flowId, 20, flowId, 0, 0, NwConstants.COOKIE_L3_GW_MAC_TABLE,
+                mkMatches, mkInstructions);
     }
 
-    static String getL3VpnGatewayFlowRef(short l3GwMacTable, BigInteger dpId, long vpnId, String gwMacAddress,
-                                         long subnetVpnId) {
+    static String getL3VpnGatewayFlowRef(short l3GwMacTable, Uint64 dpId, Uint32 vpnId, String gwMacAddress,
+                                         Uint32 subnetVpnId) {
         return gwMacAddress + NwConstants.FLOWID_SEPARATOR + vpnId + NwConstants.FLOWID_SEPARATOR + dpId
             + NwConstants.FLOWID_SEPARATOR + l3GwMacTable + NwConstants.FLOWID_SEPARATOR + subnetVpnId;
     }
 
     void lockSubnet(String subnetId) {
+        //  We set the total wait time for lock to be obtained at 9 seconds since GC pauses can be upto 8 seconds
+        //in scale setups.
         TryLockInput input =
-            new TryLockInputBuilder().setLockName(subnetId).setTime(3000L).setTimeUnit(TimeUnits.Milliseconds).build();
+            new TryLockInputBuilder().setLockName(subnetId).setTime(9000L).setTimeUnit(TimeUnits.Milliseconds).build();
         Future<RpcResult<TryLockOutput>> result = lockManager.tryLock(input);
         try {
             if (result != null && result.get().isSuccessful()) {
@@ -1356,7 +1399,7 @@ public final class VpnUtil {
 
     public Optional<String> getGWMacAddressFromInterface(MacEntry macEntry, IpAddress gatewayIp) {
         Optional<String> gatewayMac = Optional.absent();
-        long vpnId = getVpnId(macEntry.getVpnName());
+        Uint32 vpnId = getVpnId(macEntry.getVpnName());
         InstanceIdentifier<org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.l3vpn.rev130911.vpn.id.to.vpn
             .instance.VpnIds>
             vpnIdsInstanceIdentifier = VpnUtil.getVpnIdToVpnInstanceIdentifier(vpnId);
@@ -1380,7 +1423,7 @@ public final class VpnUtil {
         return gatewayMac;
     }
 
-    void setupGwMacIfExternalVpn(BigInteger dpnId, String interfaceName, long vpnId,
+    void setupGwMacIfExternalVpn(Uint64 dpnId, String interfaceName, Uint32 vpnId,
                                  TypedReadWriteTransaction<Configuration> writeInvTxn, int addOrRemove, String gwMac)
             throws ExecutionException, InterruptedException {
         InstanceIdentifier<org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.l3vpn.rev130911.vpn.id.to.vpn.instance
@@ -1393,7 +1436,7 @@ public final class VpnUtil {
                         interfaceName, dpnId.toString(), vpnIdsOptional.get().getVpnInstanceName());
                 return;
             }
-            FlowEntity flowEntity = buildL3vpnGatewayFlow(dpnId, gwMac, vpnId, VpnConstants.INVALID_ID);
+            FlowEntity flowEntity = buildL3vpnGatewayFlow(dpnId, gwMac, vpnId,VpnConstants.INVALID_ID);
             if (addOrRemove == NwConstants.ADD_FLOW) {
                 mdsalManager.addFlow(writeInvTxn, flowEntity);
             } else if (addOrRemove == NwConstants.DEL_FLOW) {
@@ -1446,13 +1489,13 @@ public final class VpnUtil {
     }
 
     @Nullable
-    BigInteger getPrimarySwitchForRouter(String routerName) {
+    Uint64 getPrimarySwitchForRouter(String routerName) {
         RouterToNaptSwitch routerToNaptSwitch = getRouterToNaptSwitch(routerName);
         return routerToNaptSwitch != null ? routerToNaptSwitch.getPrimarySwitchId() : null;
     }
 
-    static boolean isL3VpnOverVxLan(Long l3Vni) {
-        return l3Vni != null && l3Vni != 0;
+    static boolean isL3VpnOverVxLan(Uint32 l3Vni) {
+        return l3Vni != null && l3Vni.longValue() != 0;
     }
 
     /**
@@ -1499,9 +1542,9 @@ public final class VpnUtil {
         return !vpnName.equals(primaryRd);
     }
 
-    java.util.Optional<String> allocateRdForExtraRouteAndUpdateUsedRdsMap(long vpnId, @Nullable Long parentVpnId,
+    java.util.Optional<String> allocateRdForExtraRouteAndUpdateUsedRdsMap(Uint32 vpnId, @Nullable Uint32 parentVpnId,
                                                                           String prefix, String vpnName,
-                                                                          String nextHop, BigInteger dpnId) {
+                                                                          String nextHop, Uint64 dpnId) {
         //Check if rd is already allocated for this extraroute behind the same VM. If yes, reuse it.
         //This is particularly useful during reboot scenarios.
         java.util.Optional<String> allocatedRd = VpnExtraRouteHelper
@@ -1537,7 +1580,9 @@ public final class VpnUtil {
         } else {
             LOG.trace("Removing used rds {} from available rds {} vpnid {} . prefix is {} , vpname- {}, dpnId- {}",
                     usedRds, availableRds, vpnId, prefix, vpnName, dpnId);
-            availableRds.removeAll(usedRds);
+            if (!usedRds.isEmpty()) {
+                availableRds.removeAll(usedRds);
+            }
             if (availableRds.isEmpty()) {
                 LOG.error("No rd available from VpnInstance to allocate for prefix {}", prefix);
                 return java.util.Optional.empty();
@@ -1560,11 +1605,14 @@ public final class VpnUtil {
                 .augmentation(Adjacencies.class).child(Adjacency.class, new AdjacencyKey(ipAddress)).build();
     }
 
-    static InstanceIdentifier<Adjacency> getVpnInterfaceOpDataEntryAdjacencyIdentifier(String intfName, String vpnName,
-                String ipAddress) {
+    static InstanceIdentifier<Adjacency> getVpnInterfaceOpDataEntryAdjacencyIdentifier(String intfName,
+                                                                                       String vpnName,
+                                                                                       String ipAddress) {
+        LOG.debug("getVpnInterfaceOpDataEntryAdjacencyIdentifier intfName {}, vpnName {}, ipAddress {}",
+                intfName, vpnName, ipAddress);
         return InstanceIdentifier.builder(VpnInterfaceOpData.class)
-                .child(VpnInterfaceOpDataEntry.class, new VpnInterfaceOpDataEntryKey(intfName, vpnName))
-                .augmentation(AdjacenciesOp.class).child(Adjacency.class, new AdjacencyKey(ipAddress)).build();
+                    .child(VpnInterfaceOpDataEntry.class, new VpnInterfaceOpDataEntryKey(intfName, vpnName))
+                    .augmentation(AdjacenciesOp.class).child(Adjacency.class, new AdjacencyKey(ipAddress)).build();
     }
 
     public static List<String> getIpsListFromExternalIps(List<ExternalIps> externalIps) {
@@ -1592,12 +1640,13 @@ public final class VpnUtil {
     BoundServices getBoundServicesForVpnInterface(String vpnName, String interfaceName) {
         List<Instruction> instructions = new ArrayList<>();
         int instructionKey = 0;
-        final long vpnId = getVpnId(vpnName);
+        final Uint32 vpnId = getVpnId(vpnName);
         List<Action> actions = Collections.singletonList(
-                new ActionRegLoad(0, VpnConstants.VPN_REG_ID, 0, VpnConstants.VPN_ID_LENGTH, vpnId).buildAction());
+                new ActionRegLoad(0, VpnConstants.VPN_REG_ID, 0, VpnConstants.VPN_ID_LENGTH, vpnId.longValue())
+                .buildAction());
         instructions.add(MDSALUtil.buildApplyActionsInstruction(actions, ++instructionKey));
         instructions.add(
-                MDSALUtil.buildAndGetWriteMetadaInstruction(MetaDataUtil.getVpnIdMetadata(vpnId),
+                MDSALUtil.buildAndGetWriteMetadaInstruction(MetaDataUtil.getVpnIdMetadata(vpnId.longValue()),
                         MetaDataUtil.METADATA_MASK_VRFID, ++instructionKey));
         instructions.add(MDSALUtil.buildAndGetGotoTableInstruction(NwConstants.L3_GW_MAC_TABLE,
                 ++instructionKey));
@@ -1633,7 +1682,7 @@ public final class VpnUtil {
         }
     }
 
-    static FlowEntity buildFlowEntity(BigInteger dpnId, short tableId, String flowId) {
+    static FlowEntity buildFlowEntity(Uint64 dpnId, short tableId, String flowId) {
         return new FlowEntityBuilder().setDpnId(dpnId).setTableId(tableId).setFlowId(flowId).build();
     }
 
@@ -1641,8 +1690,7 @@ public final class VpnUtil {
         return isVxLan ? VrfEntryBase.EncapType.Vxlan : VrfEntryBase.EncapType.Mplsgre;
     }
 
-    @Nullable
-    org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.natservice.rev160111.external.subnets.Subnets
+    org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.natservice.rev160111.external.subnets.@Nullable Subnets
         getExternalSubnet(Uuid subnetId) {
         InstanceIdentifier<org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.natservice.rev160111.external.subnets
             .Subnets> subnetsIdentifier = InstanceIdentifier.builder(ExternalSubnets.class)
@@ -1685,7 +1733,7 @@ public final class VpnUtil {
         return read(LogicalDatastoreType.CONFIGURATION, inst).orNull();
     }
 
-    public static boolean isEligibleForBgp(@Nullable String rd, @Nullable String vpnName, @Nullable BigInteger dpnId,
+    public static boolean isEligibleForBgp(@Nullable String rd, @Nullable String vpnName, @Nullable Uint64 dpnId,
             @Nullable String networkName) {
         if (rd != null) {
             if (rd.equals(vpnName)) {
@@ -1702,14 +1750,14 @@ public final class VpnUtil {
         return false;
     }
 
-    static String getFibFlowRef(BigInteger dpnId, short tableId, String vpnName, int priority) {
+    static String getFibFlowRef(Uint64 dpnId, short tableId, String vpnName, int priority) {
         return VpnConstants.FLOWID_PREFIX + dpnId + NwConstants.FLOWID_SEPARATOR + tableId
                 + NwConstants.FLOWID_SEPARATOR + vpnName + NwConstants.FLOWID_SEPARATOR + priority;
     }
 
     void removeExternalTunnelDemuxFlows(String vpnName) {
         LOG.info("Removing external tunnel flows for vpn {}", vpnName);
-        for (BigInteger dpnId: NWUtil.getOperativeDPNs(dataBroker)) {
+        for (Uint64 dpnId: NWUtil.getOperativeDPNs(dataBroker)) {
             LOG.debug("Removing external tunnel flows for vpn {} from dpn {}", vpnName, dpnId);
             String flowRef = getFibFlowRef(dpnId, NwConstants.L3VNI_EXTERNAL_TUNNEL_DEMUX_TABLE,
                     vpnName, VpnConstants.DEFAULT_FLOW_PRIORITY);
@@ -1722,24 +1770,40 @@ public final class VpnUtil {
     public boolean isVpnPendingDelete(String rd) {
         VpnInstanceOpDataEntry vpnInstanceOpData = getVpnInstanceOpData(rd);
         boolean isVpnPendingDelete = false;
-        if (vpnInstanceOpData == null
-                || vpnInstanceOpData.getVpnState() == VpnInstanceOpDataEntry.VpnState.PendingDelete) {
+        if (vpnInstanceOpData == null) {
+            LOG.error("isVpnPendingDelete: unable to read vpn instance op data for vpn with rd {}", rd);
+            isVpnPendingDelete = true;
+        }
+        else if (vpnInstanceOpData.getVpnState() == VpnInstanceOpDataEntry.VpnState.PendingDelete) {
             isVpnPendingDelete = true;
         }
         return isVpnPendingDelete;
     }
 
+    @SuppressWarnings("checkstyle:IllegalCatch")
     public List<VpnInstanceOpDataEntry> getVpnsImportingMyRoute(final String vpnName) {
         List<VpnInstanceOpDataEntry> vpnsToImportRoute = new ArrayList<>();
+        final VpnInstanceOpDataEntry vpnInstanceOpDataEntry;
         final String vpnRd = getVpnRd(vpnName);
         if (vpnRd == null) {
             LOG.error("getVpnsImportingMyRoute: vpn {} not present in config DS.", vpnName);
             return vpnsToImportRoute;
         }
-        final VpnInstanceOpDataEntry vpnInstanceOpDataEntry = getVpnInstanceOpData(vpnRd);
-        if (vpnInstanceOpDataEntry == null) {
-            LOG.error("getVpnsImportingMyRoute: Could not retrieve vpn instance op data for {}"
-                    + " to check for vpns importing the routes", vpnName);
+        if (vpnRd.equals(vpnName)) {
+            LOG.error("getVpnsImportingMyRoute: Internal vpn {} do not export/import routes", vpnName);
+            return vpnsToImportRoute;
+        }
+        try {
+            final VpnInstanceOpDataEntry opDataEntry = getVpnInstanceOpData(vpnRd);
+            if (opDataEntry == null) {
+                LOG.error("getVpnsImportingMyRoute: Could not retrieve vpn instance op data for vpn {} rd {}"
+                        + " to check for vpns importing the routes", vpnName, vpnRd);
+                return vpnsToImportRoute;
+            }
+            vpnInstanceOpDataEntry = opDataEntry;
+        } catch (Exception e) {
+            LOG.error("getVpnsImportingMyRoute: DSException when retrieving vpn instance op data for vpn {} rd {}"
+                    + " to check for vpns importing the routes", vpnName, vpnRd);
             return vpnsToImportRoute;
         }
         Predicate<VpnInstanceOpDataEntry> excludeVpn = input -> {
@@ -1900,7 +1964,7 @@ public final class VpnUtil {
      * @param vpnName the vpnName
      * @param dpnId  the DPN id
      */
-    void addRouterPortToElanForVlanInDpn(String vpnName, BigInteger dpnId) {
+    void addRouterPortToElanForVlanInDpn(String vpnName, Uint64 dpnId) {
         Map<String,String> elanInstanceRouterPortMap = getElanInstanceRouterPortMap(vpnName);
         for (Entry<String, String> elanInstanceRouterEntry : elanInstanceRouterPortMap.entrySet()) {
             addRouterPortToElanDpn(elanInstanceRouterEntry.getKey(), elanInstanceRouterEntry.getValue(), dpnId);
@@ -1914,7 +1978,7 @@ public final class VpnUtil {
      * @param vpnName the vpn name
      * @param dpnId  the DPN id
      */
-    void removeRouterPortFromElanForVlanInDpn(String vpnName, BigInteger dpnId) {
+    void removeRouterPortFromElanForVlanInDpn(String vpnName, Uint64 dpnId) {
         Map<String,String> elanInstanceRouterPortMap = getElanInstanceRouterPortMap(vpnName);
         for (Entry<String, String> elanInstanceRouterEntry : elanInstanceRouterPortMap.entrySet()) {
             removeRouterPortFromElanDpn(elanInstanceRouterEntry.getKey(), elanInstanceRouterEntry.getValue(),
@@ -1930,8 +1994,8 @@ public final class VpnUtil {
      */
     void addRouterPortToElanDpnListForVlaninAllDpn(String vpnName) {
         Map<String,String> elanInstanceRouterPortMap = getElanInstanceRouterPortMap(vpnName);
-        Set<BigInteger> dpnList = getDpnInElan(elanInstanceRouterPortMap);
-        for (BigInteger dpnId : dpnList) {
+        Set<Uint64> dpnList = getDpnInElan(elanInstanceRouterPortMap);
+        for (Uint64 dpnId : dpnList) {
             for (Entry<String, String> elanInstanceRouterEntry : elanInstanceRouterPortMap.entrySet()) {
                 addRouterPortToElanDpn(elanInstanceRouterEntry.getKey(), elanInstanceRouterEntry.getValue(), dpnId);
             }
@@ -1949,8 +2013,8 @@ public final class VpnUtil {
             String routerInterfacePortId, String vpnName) {
         Map<String,String> elanInstanceRouterPortMap = getElanInstanceRouterPortMap(vpnName);
         elanInstanceRouterPortMap.put(elanInstanceName, routerInterfacePortId);
-        Set<BigInteger> dpnList = getDpnInElan(elanInstanceRouterPortMap);
-        for (BigInteger dpnId : dpnList) {
+        Set<Uint64> dpnList = getDpnInElan(elanInstanceRouterPortMap);
+        for (Uint64 dpnId : dpnList) {
             for (Entry<String, String> elanInstanceRouterEntry : elanInstanceRouterPortMap.entrySet()) {
                 removeRouterPortFromElanDpn(elanInstanceRouterEntry.getKey(), elanInstanceRouterEntry.getValue(),
                         vpnName, dpnId);
@@ -1959,16 +2023,15 @@ public final class VpnUtil {
 
     }
 
-    Set<BigInteger> getDpnInElan(Map<String,String> elanInstanceRouterPortMap) {
-        Set<BigInteger> dpnIdSet = new HashSet<>();
+    Set<Uint64> getDpnInElan(Map<String,String> elanInstanceRouterPortMap) {
+        Set<Uint64> dpnIdSet = new HashSet<>();
         for (String elanInstanceName : elanInstanceRouterPortMap.keySet()) {
             InstanceIdentifier<ElanDpnInterfacesList> elanDpnInterfaceId = getElanDpnOperationalDataPath(
                     elanInstanceName);
             Optional<ElanDpnInterfacesList> dpnInElanInterfaces = read(LogicalDatastoreType.OPERATIONAL,
                     elanDpnInterfaceId);
             if (dpnInElanInterfaces.isPresent()) {
-                List<DpnInterfaces> dpnInterfaces =
-                    requireNonNullElse(dpnInElanInterfaces.get().getDpnInterfaces(), emptyList());
+                List<DpnInterfaces> dpnInterfaces = dpnInElanInterfaces.get().nonnullDpnInterfaces();
                 for (DpnInterfaces dpnInterface : dpnInterfaces) {
                     dpnIdSet.add(dpnInterface.getDpId());
                 }
@@ -1977,18 +2040,21 @@ public final class VpnUtil {
         return dpnIdSet;
     }
 
-    void addRouterPortToElanDpn(String elanInstanceName, String routerInterfacePortId, BigInteger dpnId) {
+    void addRouterPortToElanDpn(String elanInstanceName, String routerInterfacePortId, Uint64 dpnId) {
         InstanceIdentifier<DpnInterfaces> elanDpnInterfaceId = getElanDpnInterfaceOperationalDataPath(
                 elanInstanceName,dpnId);
-        synchronized (elanInstanceName.intern()) {
+        final ReentrantLock lock = JvmGlobalLocks.getLockForString(elanInstanceName);
+        lock.lock();
+        try {
             Optional<DpnInterfaces> dpnInElanInterfaces = read(LogicalDatastoreType.OPERATIONAL, elanDpnInterfaceId);
-            List<String> elanInterfaceList;
+            List<String> elanInterfaceList = new ArrayList<>();
             DpnInterfaces dpnInterface;
             if (!dpnInElanInterfaces.isPresent()) {
                 elanInterfaceList = new ArrayList<>();
             } else {
                 dpnInterface = dpnInElanInterfaces.get();
-                elanInterfaceList = dpnInterface.getInterfaces();
+                elanInterfaceList = (dpnInterface.getInterfaces() != null && !dpnInterface.getInterfaces().isEmpty())
+                        ? new ArrayList<>(dpnInterface.getInterfaces()) : elanInterfaceList;
             }
             if (!elanInterfaceList.contains(routerInterfacePortId)) {
                 elanInterfaceList.add(routerInterfacePortId);
@@ -1996,24 +2062,28 @@ public final class VpnUtil {
                         .withKey(new DpnInterfacesKey(dpnId)).build();
                 syncWrite(LogicalDatastoreType.OPERATIONAL, elanDpnInterfaceId, dpnInterface);
             }
+        } finally {
+            lock.unlock();
         }
-
     }
 
     void removeRouterPortFromElanDpn(String elanInstanceName, String routerInterfacePortId,
-            String vpnName, BigInteger dpnId) {
+            String vpnName, Uint64 dpnId) {
         InstanceIdentifier<DpnInterfaces> elanDpnInterfaceId = getElanDpnInterfaceOperationalDataPath(
                 elanInstanceName,dpnId);
-        synchronized (elanInstanceName.intern()) {
+        final ReentrantLock lock = JvmGlobalLocks.getLockForString(elanInstanceName);
+        lock.lock();
+        try {
             Optional<DpnInterfaces> dpnInElanInterfaces = read(LogicalDatastoreType.OPERATIONAL, elanDpnInterfaceId);
-            List<String> elanInterfaceList;
+            List<String> elanInterfaceList = new ArrayList<>();
             DpnInterfaces dpnInterface;
             if (!dpnInElanInterfaces.isPresent()) {
                 LOG.info("No interface in any dpn for {}", vpnName);
                 return;
             } else {
                 dpnInterface = dpnInElanInterfaces.get();
-                elanInterfaceList = dpnInterface.getInterfaces();
+                elanInterfaceList = (dpnInterface.getInterfaces() != null && !dpnInterface.getInterfaces().isEmpty())
+                        ? new ArrayList<>(dpnInterface.getInterfaces()) : elanInterfaceList;
             }
             if (!elanInterfaceList.contains(routerInterfacePortId)) {
                 LOG.info("Router port not present in DPN {} for VPN {}", dpnId, vpnName);
@@ -2023,6 +2093,8 @@ public final class VpnUtil {
             dpnInterface = new DpnInterfacesBuilder().setDpId(dpnId).setInterfaces(elanInterfaceList)
                     .withKey(new DpnInterfacesKey(dpnId)).build();
             syncWrite(LogicalDatastoreType.OPERATIONAL, elanDpnInterfaceId, dpnInterface);
+        } finally {
+            lock.unlock();
         }
 
     }
@@ -2039,14 +2111,14 @@ public final class VpnUtil {
     }
 
     @Nullable
-    DpnInterfaces getElanInterfaceInfoByElanDpn(String elanInstanceName, BigInteger dpId) {
+    DpnInterfaces getElanInterfaceInfoByElanDpn(String elanInstanceName, Uint64 dpId) {
         InstanceIdentifier<DpnInterfaces> elanDpnInterfacesId = getElanDpnInterfaceOperationalDataPath(elanInstanceName,
                 dpId);
         return read(LogicalDatastoreType.OPERATIONAL, elanDpnInterfacesId).orNull();
     }
 
     @Nullable
-    String getExternalElanInterface(String elanInstanceName, BigInteger dpnId) {
+    String getExternalElanInterface(String elanInstanceName, Uint64 dpnId) {
         DpnInterfaces dpnInterfaces = getElanInterfaceInfoByElanDpn(elanInstanceName, dpnId);
         if (dpnInterfaces == null || dpnInterfaces.getInterfaces() == null) {
             LOG.info("Elan {} does not have interfaces in DPN {}", elanInstanceName, dpnId);
@@ -2064,7 +2136,7 @@ public final class VpnUtil {
     static boolean isVlan(ElanInstance elanInstance) {
         return elanInstance != null && elanInstance.getSegmentType() != null
                 && elanInstance.getSegmentType().isAssignableFrom(SegmentTypeVlan.class)
-                && elanInstance.getSegmentationId() != null && elanInstance.getSegmentationId() != 0;
+                && elanInstance.getSegmentationId() != null && elanInstance.getSegmentationId().toJava() != 0;
     }
 
     boolean isVlan(String interfaceName) {
@@ -2105,7 +2177,11 @@ public final class VpnUtil {
         Map<String, String> elanInstanceRouterPortMap = new HashMap<>();
         Optional<Subnetmaps> subnetMapsData = read(LogicalDatastoreType.CONFIGURATION, buildSubnetMapsWildCardPath());
         if (subnetMapsData.isPresent()) {
-            List<Subnetmap> subnetMapList = subnetMapsData.get().getSubnetmap();
+            List<Subnetmap> subnetMapList = new ArrayList<>();
+            Subnetmaps subnetMaps = subnetMapsData.get();
+            subnetMapList = (subnetMaps.getSubnetmap() != null && !subnetMaps.getSubnetmap().isEmpty())
+                    ? new ArrayList<>(subnetMaps.getSubnetmap()) : subnetMapList;
+
             if (subnetMapList != null && !subnetMapList.isEmpty()) {
                 for (Subnetmap subnet : subnetMapList) {
                     if (subnet.getVpnId() != null && subnet.getVpnId().getValue().equals(vpnName)
@@ -2143,7 +2219,7 @@ public final class VpnUtil {
         return null;
     }
 
-    boolean shouldPopulateFibForVlan(String vpnName, @Nullable String elanInstanceName, BigInteger dpnId) {
+    boolean shouldPopulateFibForVlan(String vpnName, @Nullable String elanInstanceName, Uint64 dpnId) {
         Map<String,String> elanInstanceRouterPortMap = getElanInstanceRouterPortMap(vpnName);
         boolean shouldPopulateFibForVlan = false;
         if (!elanInstanceRouterPortMap.isEmpty()) {
@@ -2165,7 +2241,7 @@ public final class VpnUtil {
     }
 
     public static InstanceIdentifier<DpnInterfaces> getElanDpnInterfaceOperationalDataPath(String elanInstanceName,
-            BigInteger dpId) {
+            Uint64 dpId) {
         return InstanceIdentifier.builder(ElanDpnInterfaces.class)
                 .child(ElanDpnInterfacesList.class, new ElanDpnInterfacesListKey(elanInstanceName))
                 .child(DpnInterfaces.class, new DpnInterfacesKey(dpId)).build();
@@ -2190,7 +2266,7 @@ public final class VpnUtil {
     }
 
     public static void sendNeighborSolicationToOfGroup(Ipv6NdUtilService ipv6NdUtilService, Ipv6Address srcIpv6Address,
-            MacAddress srcMac, Ipv6Address dstIpv6Address, Long ofGroupId, BigInteger dpId) {
+            MacAddress srcMac, Ipv6Address dstIpv6Address, Long ofGroupId, Uint64 dpId) {
         SendNeighborSolicitationToOfGroupInput input = new SendNeighborSolicitationToOfGroupInputBuilder()
                 .setSourceIpv6(srcIpv6Address).setSourceLlAddress(srcMac).setTargetIpAddress(dstIpv6Address)
                 .setOfGroupId(ofGroupId).setDpId(dpId).build();
@@ -2207,26 +2283,73 @@ public final class VpnUtil {
         }
     }
 
-    Set<org.opendaylight.yang.gen.v1.urn.huawei.params.xml.ns.yang.l3vpn.rev140815.vpn.af.config.vpntargets.VpnTarget>
-        getRtListForVpn(String vpnName) {
-        Set<org.opendaylight.yang.gen.v1.urn.huawei.params.xml.ns.yang.l3vpn.rev140815.vpn.af.config.vpntargets
-                .VpnTarget> rtList = new HashSet<>();
-        InstanceIdentifier<VpnInstance> vpnInstanceId = InstanceIdentifier.builder(VpnInstances.class)
-                .child(VpnInstance.class, new VpnInstanceKey(vpnName)).build();
-        Optional<VpnInstance> vpnInstanceOptional = read(LogicalDatastoreType.CONFIGURATION, vpnInstanceId);
-        if (vpnInstanceOptional.isPresent()) {
-            org.opendaylight.yang.gen.v1.urn.huawei.params.xml.ns.yang.l3vpn.rev140815.vpn.af.config.VpnTargets
-                    vpnTargets = vpnInstanceOptional.get().getIpv4Family().getVpnTargets();
-            if (vpnTargets != null && vpnTargets.getVpnTarget() != null) {
-                rtList.addAll(vpnTargets.getVpnTarget());
+    static Set<org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.neutronvpn.l3vpn.rev200204.vpn.instances.vpn
+            .instance.vpntargets.VpnTarget> getRtListForVpn(DataBroker dataBroker, String vpnName) {
+        Set<org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.neutronvpn.l3vpn.rev200204.vpn.instances.vpn
+                .instance.vpntargets.VpnTarget> rtList = new HashSet<>();
+        try {
+            InstanceIdentifier<VpnInstance> vpnInstanceId = InstanceIdentifier.builder(VpnInstances.class)
+                    .child(VpnInstance.class, new VpnInstanceKey(vpnName)).build();
+            Optional<VpnInstance> vpnInstanceOptional = SingleTransactionDataBroker.syncReadOptional(dataBroker,
+                    LogicalDatastoreType.CONFIGURATION, vpnInstanceId);
+            if (vpnInstanceOptional.isPresent()) {
+                org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.neutronvpn.l3vpn.rev200204.vpn.instances
+                        .vpn.instance.VpnTargets vpnTargets = vpnInstanceOptional.get().getVpnTargets();
+                if (vpnTargets != null && vpnTargets.getVpnTarget() != null) {
+                    rtList.addAll(vpnTargets.getVpnTarget());
+                }
+            } else {
+                LOG.error("getRtListForVpn: Vpn Instance {} not present in config DS", vpnName);
             }
-        }
-        else {
-            LOG.error("getRtListForVpn: Vpn Instance {} not present in config DS", vpnName);
+        } catch (ReadFailedException e) {
+            LOG.error("getRtListForVpn: Read failed for Vpn Instance {}", vpnName);
         }
         return rtList;
     }
 
+    /*
+    if (update == 0) {
+    removedFamily = original
+    4 removed = 4
+    6 removed = 6
+    10 removed
+    } else if (update < original) {
+    removedFamily = original - update
+    10 was there 4 removed = 6
+    10 was there 6 removed  = 4
+    } else {
+   return;
+    }
+    */
+    public static int getIpFamilyValueToRemove(VpnInstanceOpDataEntry original, VpnInstanceOpDataEntry update) {
+        int originalValue = original.getIpAddressFamilyConfigured().getIntValue();
+        int updatedValue = update.getIpAddressFamilyConfigured().getIntValue();
+
+        if (originalValue == updatedValue) {
+            return 0;
+        }
+        int removedFamily;
+        if (updatedValue == 0) {
+            removedFamily = originalValue;
+        } else if (updatedValue < originalValue) {
+            removedFamily = originalValue - updatedValue;
+        } else {
+            return 0;
+        }
+        return removedFamily;
+    }
+
+    public static int getIpFamilyValueToAdd(VpnInstanceOpDataEntry original, VpnInstanceOpDataEntry update) {
+        int originalValue = original.getIpAddressFamilyConfigured().getIntValue();
+        int updatedValue = update.getIpAddressFamilyConfigured().getIntValue();
+
+        if (originalValue != updatedValue) {
+            return updatedValue;
+        } else {
+            return originalValue;
+        }
+    }
+
     static InstanceIdentifier<AssociatedVpn> getAssociatedSubnetAndVpnIdentifier(String rt, RouteTarget.RtType rtType,
                                                                                  String cidr, String vpnName) {
         return InstanceIdentifier.builder(SubnetsAssociatedToRouteTargets.class).child(RouteTarget.class,
@@ -2249,11 +2372,11 @@ public final class VpnUtil {
                 .child(RouteTarget.class, new RouteTargetKey(rt, rtType)).build();
     }
 
-    Set<RouteTarget> getRouteTargetSet(Set<org.opendaylight.yang.gen.v1.urn.huawei.params.xml.ns.yang.l3vpn.rev140815
-            .vpn.af.config.vpntargets.VpnTarget> vpnTargets) {
+    Set<RouteTarget> getRouteTargetSet(Set<org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.neutronvpn.l3vpn
+            .rev200204.vpn.instances.vpn.instance.vpntargets.VpnTarget> vpnTargets) {
         Set<RouteTarget> routeTargetSet = new HashSet<>();
-        for (org.opendaylight.yang.gen.v1.urn.huawei.params.xml.ns.yang.l3vpn.rev140815.vpn.af.config.vpntargets
-                .VpnTarget rt : vpnTargets) {
+        for (org.opendaylight.yang.gen.v1.urn.opendaylight.netvirt.neutronvpn.l3vpn.rev200204.vpn.instances.vpn
+                .instance.vpntargets.VpnTarget rt : vpnTargets) {
             String rtValue = rt.getVrfRTValue();
             switch (rt.getVrfRTType()) {
                 case ImportExtcommunity: {
@@ -2337,7 +2460,7 @@ public final class VpnUtil {
     }
 
     public static List<String> getVpnListForVpnInterface(VpnInterface vpnInter) {
-        return requireNonNullElse(vpnInter.getVpnInstanceNames(), Collections.<VpnInstanceNames>emptyList()).stream()
+        return vpnInter.nonnullVpnInstanceNames().stream()
                 .map(VpnInstanceNames::getVpnName).collect(Collectors.toList());
     }
 
@@ -2363,10 +2486,22 @@ public final class VpnUtil {
         });
     }
 
-    // Use Objects.requireNonNullElse instead with JDK9+
-    @Nonnull
-    public static <T> T requireNonNullElse(@Nullable T obj, @Nonnull T defaultObj) {
-        return obj != null ? obj : requireNonNull(defaultObj);
+    public static RouteOrigin getRouteOrigin(AdjacencyType adjacencyType) {
+        RouteOrigin origin = RouteOrigin.LOCAL;
+        switch (adjacencyType) {
+            case PrimaryAdjacency:
+                origin = RouteOrigin.LOCAL;
+                break;
+            case ExtraRoute:
+                origin = RouteOrigin.STATIC;
+                break;
+            case LearntIp:
+                origin = RouteOrigin.DYNAMIC;
+                break;
+            default:
+                LOG.warn("Unknown adjacencyType={}", adjacencyType);
+        }
+        return origin;
     }
 
     public static boolean isDualRouterVpnUpdate(List<String> oldVpnListCopy, List<String> newVpnListCopy) {
@@ -2414,4 +2549,9 @@ public final class VpnUtil {
     public static Boolean isArpLearningEnabled() {
         return arpLearningEnabled;
     }
+
+    private static ReentrantLock lockFor(String vpnName, String fixedIp) {
+        // FIXME: is there some identifier we can use? LearntVpnVipToPortKey perhaps?
+        return JvmGlobalLocks.getLockForString(vpnName + fixedIp);
+    }
 }