impl/src/main/java/org/onosproject/segmentrouting/RouteHandler.java - trellis-control - Gitiles

 /*
  * Copyright 2016-present Open Networking Foundation
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *     http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 package org.onosproject.segmentrouting;

 import com.google.common.collect.Sets;

 import org.onlab.packet.IpPrefix;
 import org.onlab.packet.MacAddress;
 import org.onlab.packet.VlanId;
 import org.onosproject.net.ConnectPoint;
 import org.onosproject.net.Host;
 import org.onosproject.net.PortNumber;
 import org.onosproject.net.host.HostEvent;
 import org.onosproject.routeservice.ResolvedRoute;
 import org.onosproject.routeservice.RouteEvent;
 import org.onosproject.net.DeviceId;
 import org.onosproject.routeservice.RouteInfo;
 import org.onosproject.segmentrouting.config.DeviceConfigNotFoundException;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;

 import java.util.List;
 import java.util.Collection;
 import java.util.Objects;
 import java.util.Optional;
 import java.util.Set;
 import java.util.stream.Collectors;

 /**
  * Handles RouteEvent and manages routing entries.
  */
 public class RouteHandler {
     private static final Logger log = LoggerFactory.getLogger(RouteHandler.class);
     private final SegmentRoutingManager srManager;

     RouteHandler(SegmentRoutingManager srManager) {
         this.srManager = srManager;
     }

     protected void init(DeviceId deviceId) {
         srManager.routeService.getRouteTables().stream()
                 .map(srManager.routeService::getRoutes)
                 .flatMap(Collection::stream)
                 .map(RouteInfo::allRoutes)
                 .filter(allRoutes -> allRoutes.stream().anyMatch(resolvedRoute ->
                         srManager.nextHopLocations(resolvedRoute).stream()
                                 .anyMatch(cp -> deviceId.equals(cp.deviceId()))))
                 .forEach(rr -> processRouteAddedInternal(rr, true));
     }

     void processRouteAdded(RouteEvent event) {
         processRouteAddedInternal(event.alternatives(), false);
     }

     /**
      * Internal logic that handles route addition.
      *
      * @param routes collection of routes to be processed
      * @param populateRouteOnly true if we only want to populateRoute but not populateSubnet.
      *                          Set it to true when initializing a device coming up.
      *                          populateSubnet will be done when link comes up later so it is redundant.
      *                          populateRoute still needs to be done for statically configured next hop hosts.
      */
     private void processRouteAddedInternal(Collection<ResolvedRoute> routes, boolean populateRouteOnly) {
         if (!isReady()) {
             log.info("System is not ready. Skip adding route for {}", routes);
             return;
         }

         log.info("processRouteAddedInternal. routes={}", routes);

         if (routes.size() > 2) {
             log.info("Route {} has more than two next hops. Do not process route change", routes);
             return;
         }

         if (routes.isEmpty()) {
             log.warn("No resolved route found. Abort processRouteAddedInternal");
             return;
         }

         Set<ConnectPoint> allLocations = Sets.newHashSet();
         Set<IpPrefix> allPrefixes = Sets.newHashSet();
         routes.forEach(route -> {
             allLocations.addAll(srManager.nextHopLocations(route));
             allPrefixes.add(route.prefix());
         });
         log.debug("RouteAdded. populateSubnet {}, {}", allLocations, allPrefixes);
         srManager.defaultRoutingHandler.populateSubnet(allLocations, allPrefixes);

         routes.forEach(route -> {
             IpPrefix prefix = route.prefix();
             MacAddress nextHopMac = route.nextHopMac();
             VlanId nextHopVlan = route.nextHopVlan();
             Set<ConnectPoint> locations = srManager.nextHopLocations(route);

             locations.forEach(location -> {
                 log.debug("RouteAdded. addSubnet {}, {}", location, prefix);
                 srManager.deviceConfiguration.addSubnet(location, prefix);
                 log.debug("RouteAdded populateRoute {}, {}, {}, {}", location, prefix, nextHopMac, nextHopVlan);
                 srManager.defaultRoutingHandler.populateRoute(location.deviceId(), prefix,
                         nextHopMac, nextHopVlan, location.port(), false);

                 processSingleLeafPairIfNeeded(locations, location, prefix, nextHopVlan);
             });
         });
     }

     void processRouteUpdated(RouteEvent event) {
         processRouteUpdatedInternal(Sets.newHashSet(event.alternatives()),
                 Sets.newHashSet(event.prevAlternatives()));
     }

     void processAlternativeRoutesChanged(RouteEvent event) {
         processRouteUpdatedInternal(Sets.newHashSet(event.alternatives()),
                 Sets.newHashSet(event.prevAlternatives()));
     }

     private void processRouteUpdatedInternal(Set<ResolvedRoute> routes, Set<ResolvedRoute> oldRoutes) {
         if (!isReady()) {
             log.info("System is not ready. Skip updating route for {} -> {}", oldRoutes, routes);
             return;
         }

         log.info("processRouteUpdatedInternal. routes={}, oldRoutes={}", routes, oldRoutes);

         if (routes.size() > 2) {
             log.info("Route {} has more than two next hops. Do not process route change", routes);
             return;
         }

         Set<ConnectPoint> allLocations = Sets.newHashSet();
         Set<IpPrefix> allPrefixes = Sets.newHashSet();
         routes.forEach(route -> {
             allLocations.addAll(srManager.nextHopLocations(route));
             allPrefixes.add(route.prefix());
         });

         // Just come back from an invalid next hop count
         // Revoke subnet from all locations and reset oldRoutes such that system will be reprogrammed from scratch
         if (oldRoutes.size() > 2) {
             log.info("Revoke subnet {} and reset oldRoutes");
             srManager.defaultRoutingHandler.revokeSubnet(allPrefixes);
             oldRoutes = Sets.newHashSet();
         }

         log.debug("RouteUpdated. populateSubnet {}, {}", allLocations, allPrefixes);
         srManager.defaultRoutingHandler.populateSubnet(allLocations, allPrefixes);

         Set<ResolvedRoute> toBeRemoved = Sets.difference(oldRoutes, routes).immutableCopy();
         Set<ResolvedRoute> toBeAdded = Sets.difference(routes, oldRoutes).immutableCopy();

         toBeRemoved.forEach(route -> {
             srManager.nextHopLocations(route).forEach(oldLocation -> {
                 if (toBeAdded.stream().map(srManager::nextHopLocations)
                         .flatMap(Set::stream).map(ConnectPoint::deviceId)
                         .noneMatch(deviceId -> deviceId.equals(oldLocation.deviceId()))) {
                     IpPrefix prefix = route.prefix();
                     log.debug("RouteUpdated. removeSubnet {}, {}", oldLocation, prefix);
                     srManager.deviceConfiguration.removeSubnet(oldLocation, prefix);
                     // We don't remove the flow on the old location in occasion of two next hops becoming one
                     // since the populateSubnet will point the old location to the new location via spine.
                 }
             });
         });

         toBeAdded.forEach(route -> {
             IpPrefix prefix = route.prefix();
             MacAddress nextHopMac = route.nextHopMac();
             VlanId nextHopVlan = route.nextHopVlan();
             Set<ConnectPoint> locations = srManager.nextHopLocations(route);

             locations.forEach(location -> {
                 log.debug("RouteUpdated. addSubnet {}, {}", location, prefix);
                 srManager.deviceConfiguration.addSubnet(location, prefix);
                 log.debug("RouteUpdated. populateRoute {}, {}, {}, {}", location, prefix, nextHopMac, nextHopVlan);
                 srManager.defaultRoutingHandler.populateRoute(location.deviceId(), prefix,
                         nextHopMac, nextHopVlan, location.port(), false);

                 processSingleLeafPairIfNeeded(locations, location, prefix, nextHopVlan);
             });
         });
     }

     void processRouteRemoved(RouteEvent event) {
         processRouteRemovedInternal(event.alternatives());
     }

     private void processRouteRemovedInternal(Collection<ResolvedRoute> routes) {
         if (!isReady()) {
             log.info("System is not ready. Skip removing route for {}", routes);
             return;
         }

         log.info("processRouteRemovedInternal. routes={}", routes);

         Set<IpPrefix> allPrefixes = Sets.newHashSet();
         routes.forEach(route -> {
             allPrefixes.add(route.prefix());
         });
         log.debug("RouteRemoved. revokeSubnet {}", allPrefixes);
         srManager.defaultRoutingHandler.revokeSubnet(allPrefixes);

         routes.forEach(route -> {
             IpPrefix prefix = route.prefix();
             MacAddress nextHopMac = route.nextHopMac();
             VlanId nextHopVlan = route.nextHopVlan();
             Set<ConnectPoint> locations = srManager.nextHopLocations(route);

             locations.forEach(location -> {
                 log.debug("RouteRemoved. removeSubnet {}, {}", location, prefix);
                 srManager.deviceConfiguration.removeSubnet(location, prefix);
                 // We don't need to call revokeRoute again since revokeSubnet will remove the prefix
                 // from all devices, including the ones that next hop attaches to.
                 // revokeSubnet will also remove flow on the pair device (if exist) pointing to current location.
             });
         });
     }

     void processHostMovedEvent(HostEvent event) {
         log.info("processHostMovedEvent {}", event);
         MacAddress hostMac = event.subject().mac();
         VlanId hostVlanId = event.subject().vlan();

         Set<ConnectPoint> prevLocations = event.prevSubject().locations()
                 .stream().map(h -> (ConnectPoint) h)
                 .collect(Collectors.toSet());
         Set<ConnectPoint> newLocations = event.subject().locations()
                 .stream().map(h -> (ConnectPoint) h)
                 .collect(Collectors.toSet());
         List<Set<IpPrefix>> batchedSubnets =
                 srManager.deviceConfiguration.getBatchedSubnets(event.subject().id());
         Set<DeviceId> newDeviceIds = newLocations.stream().map(ConnectPoint::deviceId)
                 .collect(Collectors.toSet());

         // Set of deviceIDs of the previous locations where the host was connected
         // Used to determine if host moved to different connect points
         // on same device or moved to a different device altogether
         Set<DeviceId> oldDeviceIds = prevLocations.stream().map(ConnectPoint::deviceId)
                 .collect(Collectors.toSet());

         // L3 Ucast bucket needs to be updated only once per host
         // and only when the no. of routes with the host as next-hop is not zero
         if (!batchedSubnets.isEmpty()) {
            // For each new location, if NextObj exists for the host, update with new location ..
            Sets.difference(newLocations, prevLocations).forEach(newLocation -> {
                     // NOTE: that we use the nexthop vlanId to retrieve the nextId
                     //       while the vlanId used to program the L3 unicast chain
                     //       is derived from the port configuration. In case of
                     //       a tagged interface we use host vlanId. Host vlan should
                     //       be part of the tags configured for that port. See the
                     //       code in DefaultGroupHandler.updateL3UcastGroupBucket
                     int nextId = srManager.getMacVlanNextObjectiveId(newLocation.deviceId(),
                             hostMac, hostVlanId, null, false);
                     if (nextId != -1) {
                         //Update the nextId group bucket
                         log.debug("HostMoved. NextId exists, update L3 Ucast Group Bucket {}, {}, {} --> {}",
                                 newLocation, hostMac, hostVlanId, nextId);
                         srManager.updateMacVlanTreatment(newLocation.deviceId(), hostMac, hostVlanId,
                                 newLocation.port(), nextId);
                     } else {
                         log.debug("HostMoved. NextId does not exist for this location {}, host {}/{}",
                                 newLocation, hostMac, hostVlanId);
                     }
            });
         }

         batchedSubnets.forEach(subnets -> {
             log.debug("HostMoved. populateSubnet {}, {}", newLocations, subnets);
             srManager.defaultRoutingHandler.populateSubnet(newLocations, subnets);

             subnets.forEach(prefix -> {
                 // For each old location
                 Sets.difference(prevLocations, newLocations).forEach(prevLocation -> {

                     // Remove flows for unchanged IPs only when the host moves from a switch to another.
                     // Otherwise, do not remove and let the adding part update the old flow
                     if (newDeviceIds.contains(prevLocation.deviceId())) {
                         return;
                     }

                     log.debug("HostMoved. removeSubnet {}, {}", prevLocation, prefix);
                     srManager.deviceConfiguration.removeSubnet(prevLocation, prefix);

                     // Do not remove flow from a device if the route is still reachable via its pair device.
                     // If spine exists,
                     //     populateSubnet above will update the flow to point to its pair device via spine.
                     // If spine does not exist,
                     //     processSingleLeafPair below will update the flow to point to its pair device via pair port.
                     DeviceId pairDeviceId = srManager.getPairDeviceId(prevLocation.deviceId()).orElse(null);
                     if (newLocations.stream().anyMatch(n -> n.deviceId().equals(pairDeviceId))) {
                         return;
                     }

                     log.debug("HostMoved. revokeRoute {}, {}, {}, {}", prevLocation, prefix, hostMac, hostVlanId);
                     srManager.defaultRoutingHandler.revokeRoute(prevLocation.deviceId(), prefix,
                             hostMac, hostVlanId, prevLocation.port(), false);
                 });

                 // For each new location, add all new IPs.
                 Sets.difference(newLocations, prevLocations).forEach(newLocation -> {
                     log.debug("HostMoved. addSubnet {}, {}", newLocation, prefix);
                     srManager.deviceConfiguration.addSubnet(newLocation, prefix);

                     //its a new connect point, not a move from an existing device, populateRoute
                     if (!oldDeviceIds.contains(newLocation.deviceId())) {
                        log.debug("HostMoved. populateRoute {}, {}, {}, {}", newLocation, prefix, hostMac, hostVlanId);
                        srManager.defaultRoutingHandler.populateRoute(newLocation.deviceId(), prefix,
                               hostMac, hostVlanId, newLocation.port(), false);
                     }
                 });

                 newLocations.forEach(location -> {
                     processSingleLeafPairIfNeeded(newLocations, location, prefix, hostVlanId);
                 });
             });
         });

     }

     public void processIntfVlanUpdatedEvent(DeviceId deviceId, PortNumber portNum) {
         log.info("processIntfVlanUpdatedEvent {}/{}", deviceId, portNum);

         // Verify there are hosts attached to the port
         ConnectPoint connectPoint = new ConnectPoint(deviceId, portNum);
         Set<Host> hosts = srManager.hostService.getConnectedHosts(connectPoint);
         if (hosts == null || hosts.size() == 0) {
             log.debug("processIntfVlanUpdatedEvent: No hosts connected to {}", connectPoint);
             return;
         }

         // Iterate over the hosts and update if needed the vlan of the nextobjective
         hosts.forEach(host -> {
             // Verify if there is a nexthop and only then update the l3 indirect unicast chain
             int nextId = srManager.getMacVlanNextObjectiveId(deviceId, host.mac(), host.vlan(),
                     null, false);
             if (nextId != -1) {
                 //Update the nextId group bucket
                 log.debug("intfVlanUpdated. NextId exists, update L3 Ucast Group Bucket {}, {}, {} --> {}",
                         connectPoint, host.mac(), host.vlan(), nextId);
                 // NOTE: that we use the nexthop vlanId to retrieve the nextId
                 //       while the vlanId used to program the L3 unicast chain
                 //       is derived from the port configuration. In case of
                 //       a tagged interface we use host vlanId. Host vlan should
                 //       be part of the tags configured for that port. See the
                 //       code in DefaultGroupHandler.updateL3UcastGroupBucket
                 srManager.updateMacVlanTreatment(deviceId, host.mac(), host.vlan(), portNum, nextId);
             } else {
                 log.debug("intfVlanUpdated. NextId does not exist for this location {}, host {}/{}",
                         connectPoint, host.mac(), host.vlan());
             }
         });
     }

     private boolean isReady() {
         return Objects.nonNull(srManager.deviceConfiguration) &&
                 Objects.nonNull(srManager.defaultRoutingHandler);
     }

     protected boolean processSingleLeafPairIfNeeded(Set<ConnectPoint> locations, ConnectPoint location, IpPrefix prefix,
                                                     VlanId nextHopVlan) {
         // Special handling for single leaf pair
         if (!srManager.getInfraDeviceIds().isEmpty()) {
             log.debug("Spine found. Skip single leaf pair handling");
             return false;
         }
         Optional<DeviceId> pairDeviceId = srManager.getPairDeviceId(location.deviceId());
         if (pairDeviceId.isEmpty()) {
             log.debug("Pair device of {} not found", location.deviceId());
             return false;
         }
         if (locations.stream().anyMatch(l -> l.deviceId().equals(pairDeviceId.get()))) {
             log.debug("Pair device has a next hop available. Leave it as is.");
             return false;
         }
         Optional<PortNumber> pairRemotePort = srManager.getPairLocalPort(pairDeviceId.get());
         if (pairRemotePort.isEmpty()) {
             log.debug("Pair remote port of {} not found", pairDeviceId.get());
             return false;
         }
         // Use routerMac of the pair device as the next hop
         MacAddress effectiveMac;
         try {
             effectiveMac = srManager.getDeviceMacAddress(location.deviceId());
         } catch (DeviceConfigNotFoundException e) {
             log.warn("Abort populateRoute on pair device {}. routerMac not found", pairDeviceId);
             return false;
         }
         // Since the pairLocalPort is trunk port, use assigned vlan of original port
         // when the host is untagged
         VlanId effectiveVlan = Optional.ofNullable(srManager.getInternalVlanId(location)).orElse(nextHopVlan);

         log.debug("Single leaf pair. populateRoute {}/{}, {}, {}, {}", pairDeviceId, pairRemotePort, prefix,
                 effectiveMac, effectiveVlan);
         srManager.defaultRoutingHandler.populateRoute(pairDeviceId.get(), prefix,
                 effectiveMac, effectiveVlan, pairRemotePort.get(), false);

         return true;
     }
 }
	/*
	* Copyright 2016-present Open Networking Foundation
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	package org.onosproject.segmentrouting;

	import com.google.common.collect.Sets;

	import org.onlab.packet.IpPrefix;
	import org.onlab.packet.MacAddress;
	import org.onlab.packet.VlanId;
	import org.onosproject.net.ConnectPoint;
	import org.onosproject.net.Host;
	import org.onosproject.net.PortNumber;
	import org.onosproject.net.host.HostEvent;
	import org.onosproject.routeservice.ResolvedRoute;
	import org.onosproject.routeservice.RouteEvent;
	import org.onosproject.net.DeviceId;
	import org.onosproject.routeservice.RouteInfo;
	import org.onosproject.segmentrouting.config.DeviceConfigNotFoundException;
	import org.slf4j.Logger;
	import org.slf4j.LoggerFactory;

	import java.util.List;
	import java.util.Collection;
	import java.util.Objects;
	import java.util.Optional;
	import java.util.Set;
	import java.util.stream.Collectors;

	/**
	* Handles RouteEvent and manages routing entries.
	*/
	public class RouteHandler {
	private static final Logger log = LoggerFactory.getLogger(RouteHandler.class);
	private final SegmentRoutingManager srManager;

	RouteHandler(SegmentRoutingManager srManager) {
	this.srManager = srManager;
	}

	protected void init(DeviceId deviceId) {
	srManager.routeService.getRouteTables().stream()
	.map(srManager.routeService::getRoutes)
	.flatMap(Collection::stream)
	.map(RouteInfo::allRoutes)
	.filter(allRoutes -> allRoutes.stream().anyMatch(resolvedRoute ->
	srManager.nextHopLocations(resolvedRoute).stream()
	.anyMatch(cp -> deviceId.equals(cp.deviceId()))))
	.forEach(rr -> processRouteAddedInternal(rr, true));
	}

	void processRouteAdded(RouteEvent event) {
	processRouteAddedInternal(event.alternatives(), false);
	}

	/**
	* Internal logic that handles route addition.
	*
	* @param routes collection of routes to be processed
	* @param populateRouteOnly true if we only want to populateRoute but not populateSubnet.
	* Set it to true when initializing a device coming up.
	* populateSubnet will be done when link comes up later so it is redundant.
	* populateRoute still needs to be done for statically configured next hop hosts.
	*/
	private void processRouteAddedInternal(Collection<ResolvedRoute> routes, boolean populateRouteOnly) {
	if (!isReady()) {
	log.info("System is not ready. Skip adding route for {}", routes);
	return;
	}

	log.info("processRouteAddedInternal. routes={}", routes);

	if (routes.size() > 2) {
	log.info("Route {} has more than two next hops. Do not process route change", routes);
	return;
	}

	if (routes.isEmpty()) {
	log.warn("No resolved route found. Abort processRouteAddedInternal");
	return;
	}

	Set<ConnectPoint> allLocations = Sets.newHashSet();
	Set<IpPrefix> allPrefixes = Sets.newHashSet();
	routes.forEach(route -> {
	allLocations.addAll(srManager.nextHopLocations(route));
	allPrefixes.add(route.prefix());
	});
	log.debug("RouteAdded. populateSubnet {}, {}", allLocations, allPrefixes);
	srManager.defaultRoutingHandler.populateSubnet(allLocations, allPrefixes);

	routes.forEach(route -> {
	IpPrefix prefix = route.prefix();
	MacAddress nextHopMac = route.nextHopMac();
	VlanId nextHopVlan = route.nextHopVlan();
	Set<ConnectPoint> locations = srManager.nextHopLocations(route);

	locations.forEach(location -> {
	log.debug("RouteAdded. addSubnet {}, {}", location, prefix);
	srManager.deviceConfiguration.addSubnet(location, prefix);
	log.debug("RouteAdded populateRoute {}, {}, {}, {}", location, prefix, nextHopMac, nextHopVlan);
	srManager.defaultRoutingHandler.populateRoute(location.deviceId(), prefix,
	nextHopMac, nextHopVlan, location.port(), false);

	processSingleLeafPairIfNeeded(locations, location, prefix, nextHopVlan);
	});
	});
	}

	void processRouteUpdated(RouteEvent event) {
	processRouteUpdatedInternal(Sets.newHashSet(event.alternatives()),
	Sets.newHashSet(event.prevAlternatives()));
	}

	void processAlternativeRoutesChanged(RouteEvent event) {
	processRouteUpdatedInternal(Sets.newHashSet(event.alternatives()),
	Sets.newHashSet(event.prevAlternatives()));
	}

	private void processRouteUpdatedInternal(Set<ResolvedRoute> routes, Set<ResolvedRoute> oldRoutes) {
	if (!isReady()) {
	log.info("System is not ready. Skip updating route for {} -> {}", oldRoutes, routes);
	return;
	}

	log.info("processRouteUpdatedInternal. routes={}, oldRoutes={}", routes, oldRoutes);

	if (routes.size() > 2) {
	log.info("Route {} has more than two next hops. Do not process route change", routes);
	return;
	}

	Set<ConnectPoint> allLocations = Sets.newHashSet();
	Set<IpPrefix> allPrefixes = Sets.newHashSet();
	routes.forEach(route -> {
	allLocations.addAll(srManager.nextHopLocations(route));
	allPrefixes.add(route.prefix());
	});

	// Just come back from an invalid next hop count
	// Revoke subnet from all locations and reset oldRoutes such that system will be reprogrammed from scratch
	if (oldRoutes.size() > 2) {
	log.info("Revoke subnet {} and reset oldRoutes");
	srManager.defaultRoutingHandler.revokeSubnet(allPrefixes);
	oldRoutes = Sets.newHashSet();
	}

	log.debug("RouteUpdated. populateSubnet {}, {}", allLocations, allPrefixes);
	srManager.defaultRoutingHandler.populateSubnet(allLocations, allPrefixes);

	Set<ResolvedRoute> toBeRemoved = Sets.difference(oldRoutes, routes).immutableCopy();
	Set<ResolvedRoute> toBeAdded = Sets.difference(routes, oldRoutes).immutableCopy();

	toBeRemoved.forEach(route -> {
	srManager.nextHopLocations(route).forEach(oldLocation -> {
	if (toBeAdded.stream().map(srManager::nextHopLocations)
	.flatMap(Set::stream).map(ConnectPoint::deviceId)
	.noneMatch(deviceId -> deviceId.equals(oldLocation.deviceId()))) {
	IpPrefix prefix = route.prefix();
	log.debug("RouteUpdated. removeSubnet {}, {}", oldLocation, prefix);
	srManager.deviceConfiguration.removeSubnet(oldLocation, prefix);
	// We don't remove the flow on the old location in occasion of two next hops becoming one
	// since the populateSubnet will point the old location to the new location via spine.
	}
	});
	});

	toBeAdded.forEach(route -> {
	IpPrefix prefix = route.prefix();
	MacAddress nextHopMac = route.nextHopMac();
	VlanId nextHopVlan = route.nextHopVlan();
	Set<ConnectPoint> locations = srManager.nextHopLocations(route);

	locations.forEach(location -> {
	log.debug("RouteUpdated. addSubnet {}, {}", location, prefix);
	srManager.deviceConfiguration.addSubnet(location, prefix);
	log.debug("RouteUpdated. populateRoute {}, {}, {}, {}", location, prefix, nextHopMac, nextHopVlan);
	srManager.defaultRoutingHandler.populateRoute(location.deviceId(), prefix,
	nextHopMac, nextHopVlan, location.port(), false);

	processSingleLeafPairIfNeeded(locations, location, prefix, nextHopVlan);
	});
	});
	}

	void processRouteRemoved(RouteEvent event) {
	processRouteRemovedInternal(event.alternatives());
	}

	private void processRouteRemovedInternal(Collection<ResolvedRoute> routes) {
	if (!isReady()) {
	log.info("System is not ready. Skip removing route for {}", routes);
	return;
	}

	log.info("processRouteRemovedInternal. routes={}", routes);

	Set<IpPrefix> allPrefixes = Sets.newHashSet();
	routes.forEach(route -> {
	allPrefixes.add(route.prefix());
	});
	log.debug("RouteRemoved. revokeSubnet {}", allPrefixes);
	srManager.defaultRoutingHandler.revokeSubnet(allPrefixes);

	routes.forEach(route -> {
	IpPrefix prefix = route.prefix();
	MacAddress nextHopMac = route.nextHopMac();
	VlanId nextHopVlan = route.nextHopVlan();
	Set<ConnectPoint> locations = srManager.nextHopLocations(route);

	locations.forEach(location -> {
	log.debug("RouteRemoved. removeSubnet {}, {}", location, prefix);
	srManager.deviceConfiguration.removeSubnet(location, prefix);
	// We don't need to call revokeRoute again since revokeSubnet will remove the prefix
	// from all devices, including the ones that next hop attaches to.
	// revokeSubnet will also remove flow on the pair device (if exist) pointing to current location.
	});
	});
	}

	void processHostMovedEvent(HostEvent event) {
	log.info("processHostMovedEvent {}", event);
	MacAddress hostMac = event.subject().mac();
	VlanId hostVlanId = event.subject().vlan();

	Set<ConnectPoint> prevLocations = event.prevSubject().locations()
	.stream().map(h -> (ConnectPoint) h)
	.collect(Collectors.toSet());
	Set<ConnectPoint> newLocations = event.subject().locations()
	.stream().map(h -> (ConnectPoint) h)
	.collect(Collectors.toSet());
	List<Set<IpPrefix>> batchedSubnets =
	srManager.deviceConfiguration.getBatchedSubnets(event.subject().id());
	Set<DeviceId> newDeviceIds = newLocations.stream().map(ConnectPoint::deviceId)
	.collect(Collectors.toSet());

	// Set of deviceIDs of the previous locations where the host was connected
	// Used to determine if host moved to different connect points
	// on same device or moved to a different device altogether
	Set<DeviceId> oldDeviceIds = prevLocations.stream().map(ConnectPoint::deviceId)
	.collect(Collectors.toSet());

	// L3 Ucast bucket needs to be updated only once per host
	// and only when the no. of routes with the host as next-hop is not zero
	if (!batchedSubnets.isEmpty()) {
	// For each new location, if NextObj exists for the host, update with new location ..
	Sets.difference(newLocations, prevLocations).forEach(newLocation -> {
	// NOTE: that we use the nexthop vlanId to retrieve the nextId
	// while the vlanId used to program the L3 unicast chain
	// is derived from the port configuration. In case of
	// a tagged interface we use host vlanId. Host vlan should
	// be part of the tags configured for that port. See the
	// code in DefaultGroupHandler.updateL3UcastGroupBucket
	int nextId = srManager.getMacVlanNextObjectiveId(newLocation.deviceId(),
	hostMac, hostVlanId, null, false);
	if (nextId != -1) {
	//Update the nextId group bucket
	log.debug("HostMoved. NextId exists, update L3 Ucast Group Bucket {}, {}, {} --> {}",
	newLocation, hostMac, hostVlanId, nextId);
	srManager.updateMacVlanTreatment(newLocation.deviceId(), hostMac, hostVlanId,
	newLocation.port(), nextId);
	} else {
	log.debug("HostMoved. NextId does not exist for this location {}, host {}/{}",
	newLocation, hostMac, hostVlanId);
	}
	});
	}

	batchedSubnets.forEach(subnets -> {
	log.debug("HostMoved. populateSubnet {}, {}", newLocations, subnets);
	srManager.defaultRoutingHandler.populateSubnet(newLocations, subnets);

	subnets.forEach(prefix -> {
	// For each old location
	Sets.difference(prevLocations, newLocations).forEach(prevLocation -> {

	// Remove flows for unchanged IPs only when the host moves from a switch to another.
	// Otherwise, do not remove and let the adding part update the old flow
	if (newDeviceIds.contains(prevLocation.deviceId())) {
	return;
	}

	log.debug("HostMoved. removeSubnet {}, {}", prevLocation, prefix);
	srManager.deviceConfiguration.removeSubnet(prevLocation, prefix);

	// Do not remove flow from a device if the route is still reachable via its pair device.
	// If spine exists,
	// populateSubnet above will update the flow to point to its pair device via spine.
	// If spine does not exist,
	// processSingleLeafPair below will update the flow to point to its pair device via pair port.
	DeviceId pairDeviceId = srManager.getPairDeviceId(prevLocation.deviceId()).orElse(null);
	if (newLocations.stream().anyMatch(n -> n.deviceId().equals(pairDeviceId))) {
	return;
	}

	log.debug("HostMoved. revokeRoute {}, {}, {}, {}", prevLocation, prefix, hostMac, hostVlanId);
	srManager.defaultRoutingHandler.revokeRoute(prevLocation.deviceId(), prefix,
	hostMac, hostVlanId, prevLocation.port(), false);
	});

	// For each new location, add all new IPs.
	Sets.difference(newLocations, prevLocations).forEach(newLocation -> {
	log.debug("HostMoved. addSubnet {}, {}", newLocation, prefix);
	srManager.deviceConfiguration.addSubnet(newLocation, prefix);

	//its a new connect point, not a move from an existing device, populateRoute
	if (!oldDeviceIds.contains(newLocation.deviceId())) {
	log.debug("HostMoved. populateRoute {}, {}, {}, {}", newLocation, prefix, hostMac, hostVlanId);
	srManager.defaultRoutingHandler.populateRoute(newLocation.deviceId(), prefix,
	hostMac, hostVlanId, newLocation.port(), false);
	}
	});

	newLocations.forEach(location -> {
	processSingleLeafPairIfNeeded(newLocations, location, prefix, hostVlanId);
	});
	});
	});

	}

	public void processIntfVlanUpdatedEvent(DeviceId deviceId, PortNumber portNum) {
	log.info("processIntfVlanUpdatedEvent {}/{}", deviceId, portNum);

	// Verify there are hosts attached to the port
	ConnectPoint connectPoint = new ConnectPoint(deviceId, portNum);
	Set<Host> hosts = srManager.hostService.getConnectedHosts(connectPoint);
	if (hosts == null \|\| hosts.size() == 0) {
	log.debug("processIntfVlanUpdatedEvent: No hosts connected to {}", connectPoint);
	return;
	}

	// Iterate over the hosts and update if needed the vlan of the nextobjective
	hosts.forEach(host -> {
	// Verify if there is a nexthop and only then update the l3 indirect unicast chain
	int nextId = srManager.getMacVlanNextObjectiveId(deviceId, host.mac(), host.vlan(),
	null, false);
	if (nextId != -1) {
	//Update the nextId group bucket
	log.debug("intfVlanUpdated. NextId exists, update L3 Ucast Group Bucket {}, {}, {} --> {}",
	connectPoint, host.mac(), host.vlan(), nextId);
	// NOTE: that we use the nexthop vlanId to retrieve the nextId
	// while the vlanId used to program the L3 unicast chain
	// is derived from the port configuration. In case of
	// a tagged interface we use host vlanId. Host vlan should
	// be part of the tags configured for that port. See the
	// code in DefaultGroupHandler.updateL3UcastGroupBucket
	srManager.updateMacVlanTreatment(deviceId, host.mac(), host.vlan(), portNum, nextId);
	} else {
	log.debug("intfVlanUpdated. NextId does not exist for this location {}, host {}/{}",
	connectPoint, host.mac(), host.vlan());
	}
	});
	}

	private boolean isReady() {
	return Objects.nonNull(srManager.deviceConfiguration) &&
	Objects.nonNull(srManager.defaultRoutingHandler);
	}

	protected boolean processSingleLeafPairIfNeeded(Set<ConnectPoint> locations, ConnectPoint location, IpPrefix prefix,
	VlanId nextHopVlan) {
	// Special handling for single leaf pair
	if (!srManager.getInfraDeviceIds().isEmpty()) {
	log.debug("Spine found. Skip single leaf pair handling");
	return false;
	}
	Optional<DeviceId> pairDeviceId = srManager.getPairDeviceId(location.deviceId());
	if (pairDeviceId.isEmpty()) {
	log.debug("Pair device of {} not found", location.deviceId());
	return false;
	}
	if (locations.stream().anyMatch(l -> l.deviceId().equals(pairDeviceId.get()))) {
	log.debug("Pair device has a next hop available. Leave it as is.");
	return false;
	}
	Optional<PortNumber> pairRemotePort = srManager.getPairLocalPort(pairDeviceId.get());
	if (pairRemotePort.isEmpty()) {
	log.debug("Pair remote port of {} not found", pairDeviceId.get());
	return false;
	}
	// Use routerMac of the pair device as the next hop
	MacAddress effectiveMac;
	try {
	effectiveMac = srManager.getDeviceMacAddress(location.deviceId());
	} catch (DeviceConfigNotFoundException e) {
	log.warn("Abort populateRoute on pair device {}. routerMac not found", pairDeviceId);
	return false;
	}
	// Since the pairLocalPort is trunk port, use assigned vlan of original port
	// when the host is untagged
	VlanId effectiveVlan = Optional.ofNullable(srManager.getInternalVlanId(location)).orElse(nextHopVlan);

	log.debug("Single leaf pair. populateRoute {}/{}, {}, {}, {}", pairDeviceId, pairRemotePort, prefix,
	effectiveMac, effectiveVlan);
	srManager.defaultRoutingHandler.populateRoute(pairDeviceId.get(), prefix,
	effectiveMac, effectiveVlan, pairRemotePort.get(), false);

	return true;
	}
	}