CORD-60 Support dynamic vSG creation/deletion

We no longer need to configure /32 IP in interfaces.
SR will push a per-host route when discovering a host
with IP address(es) that does not belong to configured subnet.

Also includes:
- HostHandler refactoring

Change-Id: Ic1ad42d1ccdfee32be85f49e6fc94d9026000ffc

@@ -15,11 +15,13 @@
  */
 package org.onosproject.segmentrouting;
 
+import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Maps;
 import com.google.common.collect.Sets;
 import org.onlab.packet.Ip4Address;
 import org.onlab.packet.Ip4Prefix;
 import org.onlab.packet.IpPrefix;
+import org.onosproject.net.ConnectPoint;
 import org.onosproject.net.Device;
 import org.onosproject.net.DeviceId;
 import org.onosproject.net.Link;
@@ -45,9 +47,9 @@ import static com.google.common.base.Preconditions.checkNotNull;
  * routing rule population.
  */
 public class DefaultRoutingHandler {
-
-    private static Logger log = LoggerFactory
-            .getLogger(DefaultRoutingHandler.class);
+    private static final int MAX_RETRY_ATTEMPTS = 5;
+    private static final String ECMPSPG_MISSING = "ECMP shortest path graph not found";
+    private static Logger log = LoggerFactory.getLogger(DefaultRoutingHandler.class);
 
     private SegmentRoutingManager srManager;
     private RoutingRulePopulator rulePopulator;
@@ -56,7 +58,6 @@ public class DefaultRoutingHandler {
     private DeviceConfiguration config;
     private final Lock statusLock = new ReentrantLock();
     private volatile Status populationStatus;
-    private static final int MAX_RETRY_ATTEMPTS = 5;
     private ScheduledExecutorService executorService = Executors.newScheduledThreadPool(1);
 
     /**
@@ -113,7 +114,7 @@ public class DefaultRoutingHandler {
                 }
 
                 EcmpShortestPathGraph ecmpSpg = new EcmpShortestPathGraph(sw.id(), srManager);
-                if (!populateEcmpRoutingRules(sw.id(), ecmpSpg)) {
+                if (!populateEcmpRoutingRules(sw.id(), ecmpSpg, ImmutableSet.of())) {
                     log.debug("populateAllRoutingRules: populationStatus is ABORTED");
                     populationStatus = Status.ABORTED;
                     log.debug("Abort routing rule population");
@@ -210,7 +211,7 @@ public class DefaultRoutingHandler {
             if (link.size() == 1) {
                 log.trace("repopulateRoutingRulesForRoutes: running ECMP graph for device {}", link.get(0));
                 EcmpShortestPathGraph ecmpSpg = new EcmpShortestPathGraph(link.get(0), srManager);
-                if (populateEcmpRoutingRules(link.get(0), ecmpSpg)) {
+                if (populateEcmpRoutingRules(link.get(0), ecmpSpg, ImmutableSet.of())) {
                     log.debug("Populating flow rules from {} to all is successful",
                               link.get(0));
                     currentEcmpSpgMap.put(link.get(0), ecmpSpg);
@@ -255,7 +256,8 @@ public class DefaultRoutingHandler {
                                 nextHops.add(via.get(0));
                             }
                         }
-                        if (!populateEcmpRoutingRulePartial(targetSw, dst, nextHops)) {
+                        if (!populateEcmpRoutingRulePartial(targetSw, dst,
+                                nextHops, ImmutableSet.of())) {
                             return false;
                         }
                         log.debug("Populating flow rules from {} to {} is successful",
@@ -422,8 +424,17 @@ public class DefaultRoutingHandler {
         return subLinks;
     }
 
+    /**
+     * Populate ECMP rules for subnets from all switches to destination.
+     *
+     * @param destSw Device ID of destination switch
+     * @param ecmpSPG ECMP shortest path graph
+     * @param subnets Subnets to be populated. If empty, populate all configured subnets.
+     * @return true if succeed
+     */
     private boolean populateEcmpRoutingRules(DeviceId destSw,
-                                             EcmpShortestPathGraph ecmpSPG) {
+                                             EcmpShortestPathGraph ecmpSPG,
+                                             Set<Ip4Prefix> subnets) {
 
         HashMap<Integer, HashMap<DeviceId, ArrayList<ArrayList<DeviceId>>>> switchVia = ecmpSPG
                 .getAllLearnedSwitchesAndVia();
@@ -440,7 +451,7 @@ public class DefaultRoutingHandler {
                         nextHops.add(via.get(0));
                     }
                 }
-                if (!populateEcmpRoutingRulePartial(targetSw, destSw, nextHops)) {
+                if (!populateEcmpRoutingRulePartial(targetSw, destSw, nextHops, subnets)) {
                     return false;
                 }
             }
@@ -449,9 +460,19 @@ public class DefaultRoutingHandler {
         return true;
     }
 
+    /**
+     * Populate ECMP rules for subnets from target to destination via nexthops.
+     *
+     * @param targetSw Device ID of target switch
+     * @param destSw Device ID of destination switch
+     * @param nextHops List of next hops
+     * @param subnets Subnets to be populated. If empty, populate all configured subnets.
+     * @return true if succeed
+     */
     private boolean populateEcmpRoutingRulePartial(DeviceId targetSw,
                                                    DeviceId destSw,
-                                                   Set<DeviceId> nextHops) {
+                                                   Set<DeviceId> nextHops,
+                                                   Set<Ip4Prefix> subnets) {
         boolean result;
 
         if (nextHops.isEmpty()) {
@@ -473,13 +494,11 @@ public class DefaultRoutingHandler {
         }
 
         if (targetIsEdge && destIsEdge) {
-            Set<Ip4Prefix> subnets = config.getSubnets(destSw);
+            subnets = (subnets != null && !subnets.isEmpty()) ? subnets : config.getSubnets(destSw);
             log.debug("* populateEcmpRoutingRulePartial in device {} towards {} for subnets {}",
                       targetSw, destSw, subnets);
-            result = rulePopulator.populateIpRuleForSubnet(targetSw,
-                                                           subnets,
-                                                           destSw,
-                                                           nextHops);
+            result = rulePopulator.populateIpRuleForSubnet(targetSw, subnets,
+                                                           destSw, nextHops);
             if (!result) {
                 return false;
             }
@@ -575,18 +594,54 @@ public class DefaultRoutingHandler {
         }
     }
 
-    public void purgeEcmpGraph(DeviceId deviceId) {
+    /**
+     * Populate rules of given subnet at given location.
+     *
+     * @param cp connect point of the subnet being added
+     * @param subnets subnet being added
+     * @return true if succeed
+     */
+    protected boolean populateSubnet(ConnectPoint cp, Set<Ip4Prefix> subnets) {
+        statusLock.lock();
+        try {
+            EcmpShortestPathGraph ecmpSpg = currentEcmpSpgMap.get(cp.deviceId());
+            if (ecmpSpg == null) {
+                log.warn("Fail to populating subnet {}: {}", subnets, ECMPSPG_MISSING);
+                return false;
+            }
+            return populateEcmpRoutingRules(cp.deviceId(), ecmpSpg, subnets);
+        } finally {
+            statusLock.unlock();
+        }
+    }
+
+    /**
+     * Revoke rules of given subnet at given location.
+     *
+     * @param subnets subnet being removed
+     * @return true if succeed
+     */
+    protected boolean revokeSubnet(Set<Ip4Prefix> subnets) {
+        statusLock.lock();
+        try {
+            return srManager.routingRulePopulator.revokeIpRuleForSubnet(subnets);
+        } finally {
+            statusLock.unlock();
+        }
+    }
+
+    protected void purgeEcmpGraph(DeviceId deviceId) {
         currentEcmpSpgMap.remove(deviceId);
         if (updatedEcmpSpgMap != null) {
             updatedEcmpSpgMap.remove(deviceId);
         }
     }
 
-    private class RetryFilters implements Runnable {
+    private final class RetryFilters implements Runnable {
         int attempts = MAX_RETRY_ATTEMPTS;
         DeviceId devId;
 
-        public RetryFilters(DeviceId deviceId) {
+        private RetryFilters(DeviceId deviceId) {
             devId = deviceId;
         }
 

@@ -212,22 +212,33 @@ public class RoutingRulePopulator {
      * Populates IP flow rules for the subnets of the destination router.
      *
      * @param deviceId switch ID to set the rules
-     * @param subnets subnet information
+     * @param subnets subnet being added
      * @param destSw destination switch ID
      * @param nextHops next hop switch ID list
      * @return true if all rules are set successfully, false otherwise
      */
-    public boolean populateIpRuleForSubnet(DeviceId deviceId,
-                                           Set<Ip4Prefix> subnets,
-                                           DeviceId destSw,
-                                           Set<DeviceId> nextHops) {
-
+    public boolean populateIpRuleForSubnet(DeviceId deviceId, Set<Ip4Prefix> subnets,
+            DeviceId destSw, Set<DeviceId> nextHops) {
         for (IpPrefix subnet : subnets) {
             if (!populateIpRuleForRouter(deviceId, subnet, destSw, nextHops)) {
                 return false;
             }
         }
+        return true;
+    }
 
+    /**
+     * Revokes IP flow rules for the subnets.
+     *
+     * @param subnets subnet being removed
+     * @return true if all rules are removed successfully, false otherwise
+     */
+    public boolean revokeIpRuleForSubnet(Set<Ip4Prefix> subnets) {
+        for (IpPrefix subnet : subnets) {
+            if (!revokeIpRuleForRouter(subnet)) {
+                return false;
+            }
+        }
         return true;
     }
 
@@ -310,6 +321,40 @@ public class RoutingRulePopulator {
     }
 
     /**
+     * Revokes IP flow rules for the router IP address.
+     *
+     * @param ipPrefix the IP address of the destination router
+     * @return true if all rules are removed successfully, false otherwise
+     */
+    public boolean revokeIpRuleForRouter(IpPrefix ipPrefix) {
+        TrafficSelector.Builder sbuilder = DefaultTrafficSelector.builder();
+        sbuilder.matchIPDst(ipPrefix);
+        sbuilder.matchEthType(Ethernet.TYPE_IPV4);
+        TrafficSelector selector = sbuilder.build();
+        TrafficTreatment dummyTreatment = DefaultTrafficTreatment.builder().build();
+
+        ForwardingObjective.Builder fwdBuilder = DefaultForwardingObjective
+                .builder()
+                .fromApp(srManager.appId)
+                .makePermanent()
+                .withSelector(selector)
+                .withTreatment(dummyTreatment)
+                .withPriority(getPriorityFromPrefix(ipPrefix))
+                .withFlag(ForwardingObjective.Flag.SPECIFIC);
+
+        ObjectiveContext context = new DefaultObjectiveContext(
+                (objective) -> log.debug("IP rule for router {} revoked", ipPrefix),
+                (objective, error) ->
+                        log.warn("Failed to revoke IP rule for router {}: {}", ipPrefix, error));
+
+        srManager.deviceService.getAvailableDevices().forEach(device -> {
+            srManager.flowObjectiveService.forward(device.id(), fwdBuilder.remove(context));
+        });
+
+        return true;
+    }
+
+    /**
      * Populates MPLS flow rules to all routers.
      *
      * @param deviceId target device ID of the switch to set the rules
@@ -471,6 +516,7 @@ public class RoutingRulePopulator {
      * that drivers can obtain other information (like Router MAC and IP).
      *
      * @param deviceId  the switch dpid for the router
+     * @return true if operation succeeds
      */
     public boolean populateRouterMacVlanFilters(DeviceId deviceId) {
         log.debug("Installing per-port filtering objective for untagged "

@@ -153,7 +153,7 @@ public class SegmentRoutingManager implements SegmentRoutingService {
     protected ApplicationId appId;
     protected DeviceConfiguration deviceConfiguration = null;
 
-    private DefaultRoutingHandler defaultRoutingHandler = null;
+    protected DefaultRoutingHandler defaultRoutingHandler = null;
     private TunnelHandler tunnelHandler = null;
     private PolicyHandler policyHandler = null;
     private InternalPacketProcessor processor = null;

@@ -46,6 +46,8 @@ import java.util.Optional;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 
+import static com.google.common.base.Preconditions.checkNotNull;
+
 /**
  * Segment Routing configuration component that reads the
  * segment routing related configuration from Network Configuration Manager
@@ -167,7 +169,6 @@ public class DeviceConfiguration implements DeviceProperties {
                     }
                 }
             });
-
         });
     }
 
@@ -517,4 +518,38 @@ public class DeviceConfiguration implements DeviceProperties {
                 cfgService.getConfig(appId, SegmentRoutingAppConfig.class);
         return (appConfig != null) ? appConfig.suppressHost() : ImmutableSet.of();
     }
+
+    /**
+     * Add subnet to specific connect point.
+     *
+     * @param cp connect point
+     * @param ip4Prefix subnet being added to the device
+     */
+    public void addSubnet(ConnectPoint cp, Ip4Prefix ip4Prefix) {
+        checkNotNull(cp);
+        checkNotNull(ip4Prefix);
+        SegmentRouterInfo srinfo = deviceConfigMap.get(cp.deviceId());
+        if (srinfo == null) {
+            log.warn("Device {} is not configured. Abort.", cp.deviceId());
+            return;
+        }
+        srinfo.subnets.put(cp.port(), ip4Prefix);
+    }
+
+    /**
+     * Remove subnet from specific connect point.
+     *
+     * @param cp connect point
+     * @param ip4Prefix subnet being removed to the device
+     */
+    public void removeSubnet(ConnectPoint cp, Ip4Prefix ip4Prefix) {
+        checkNotNull(cp);
+        checkNotNull(ip4Prefix);
+        SegmentRouterInfo srinfo = deviceConfigMap.get(cp.deviceId());
+        if (srinfo == null) {
+            log.warn("Device {} is not configured. Abort.", cp.deviceId());
+            return;
+        }
+        srinfo.subnets.remove(cp.port(), ip4Prefix);
+    }
 }

@@ -13,12 +13,6 @@
             },
             {
                 "vlan" : "222"
-            },
-            {
-                "ips" : [
-                    "A.A.A.146/32", "A.A.A.147/32", "A.A.A.148/32", "A.A.A.149/32",
-                    "A.A.A.150/32", "A.A.A.151/32", "A.A.A.152/32", "A.A.A.153/32"
-                ]
             }
         ]
     },
@@ -52,9 +46,6 @@
         "interfaces" : [
             {
                 "ips" : [ "10.0.2.254/24" ]
-            },
-            {
-                "ips" : [ "A.A.A.130/32", "A.A.A.131/32" ]
             }
         ]
     },