Fix: do not install unnecessary rules for stateful SNAT case

Change-Id: I4493db87193982e5d02f77711bca96ba4f7daa69
diff --git a/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/cli/BooleanCompleter.java b/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/cli/BooleanCompleter.java
new file mode 100644
index 0000000..182254a
--- /dev/null
+++ b/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/cli/BooleanCompleter.java
@@ -0,0 +1,37 @@
+/*
+ * Copyright 2019-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.openstacknetworking.cli;
+
+import com.google.common.collect.Lists;
+import org.apache.karaf.shell.api.action.lifecycle.Service;
+import org.onosproject.cli.AbstractChoicesCompleter;
+
+import java.util.List;
+
+/**
+ * Boolean completer.
+ */
+@Service
+public class BooleanCompleter extends AbstractChoicesCompleter {
+
+    @Override
+    protected List<String> choices() {
+        List<String> strings = Lists.newArrayList();
+        strings.add("true");
+        strings.add("false");
+        return strings;
+    }
+}
diff --git a/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/cli/OpenstackConfigStatefulSnatCommand.java b/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/cli/OpenstackConfigStatefulSnatCommand.java
new file mode 100644
index 0000000..b55ef23
--- /dev/null
+++ b/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/cli/OpenstackConfigStatefulSnatCommand.java
@@ -0,0 +1,106 @@
+/*
+ * Copyright 2019-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.openstacknetworking.cli;
+
+import org.apache.karaf.shell.api.action.Argument;
+import org.apache.karaf.shell.api.action.Command;
+import org.apache.karaf.shell.api.action.Completion;
+import org.apache.karaf.shell.api.action.lifecycle.Service;
+import org.onosproject.cfg.ComponentConfigService;
+import org.onosproject.cli.AbstractShellCommand;
+import org.onosproject.core.ApplicationId;
+import org.onosproject.core.CoreService;
+import org.onosproject.net.flow.FlowRuleService;
+import org.onosproject.openstacknetworking.api.Constants;
+import org.onosproject.openstacknetworking.impl.OpenstackRoutingSnatHandler;
+import org.onosproject.openstacknode.api.NodeState;
+import org.onosproject.openstacknode.api.OpenstackNode;
+import org.onosproject.openstacknode.api.OpenstackNodeAdminService;
+import org.onosproject.openstacknode.api.OpenstackNodeService;
+
+import static org.onosproject.openstacknetworking.util.OpenstackNetworkingUtil.getPropertyValueAsBoolean;
+
+/**
+ * Configure stateful SNAT mode.
+ */
+@Service
+@Command(scope = "onos", name = "openstack-config-stateful-snat",
+        description = "Re-configure stateful SNAT mode (true | false)")
+public class OpenstackConfigStatefulSnatCommand extends AbstractShellCommand {
+
+    private static final String USE_STATEFUL_SNAT = "useStatefulSnat";
+
+    @Argument(index = 0, name = "statefulSnat",
+            description = "Stateful SNAT mode (true | false)",
+            required = true, multiValued = false)
+    @Completion(BooleanCompleter.class)
+    boolean statefulSnat;
+
+    @Override
+    protected void doExecute() {
+
+        configSnatMode(statefulSnat);
+
+        ComponentConfigService service = get(ComponentConfigService.class);
+        String snatComponent = OpenstackRoutingSnatHandler.class.getName();
+
+        while (true) {
+            boolean snatValue =
+                    getPropertyValueAsBoolean(
+                            service.getProperties(snatComponent), USE_STATEFUL_SNAT);
+
+            if (statefulSnat == snatValue) {
+                break;
+            }
+        }
+
+        purgeRules();
+        syncRules();
+    }
+
+    private void configSnatMode(boolean snatMode) {
+        ComponentConfigService service = get(ComponentConfigService.class);
+        String snatComponent = OpenstackRoutingSnatHandler.class.getName();
+
+        service.setProperty(snatComponent, USE_STATEFUL_SNAT, String.valueOf(snatMode));
+    }
+
+    private void purgeRules() {
+        FlowRuleService flowRuleService = get(FlowRuleService.class);
+        CoreService coreService = get(CoreService.class);
+        ApplicationId appId = coreService.getAppId(Constants.OPENSTACK_NETWORKING_APP_ID);
+        if (appId == null) {
+            error("Failed to purge OpenStack networking flow rules.");
+            return;
+        }
+        flowRuleService.removeFlowRulesById(appId);
+    }
+
+    private void syncRules() {
+        // All handlers in this application reacts the node complete event and
+        // tries to re-configure flow rules for the complete node.
+        OpenstackNodeService osNodeService = get(OpenstackNodeService.class);
+        OpenstackNodeAdminService osNodeAdminService = get(OpenstackNodeAdminService.class);
+        if (osNodeService == null) {
+            error("Failed to re-install flow rules for OpenStack networking.");
+            return;
+        }
+        osNodeService.completeNodes().forEach(osNode -> {
+            OpenstackNode updated = osNode.updateState(NodeState.INIT);
+            osNodeAdminService.updateNode(updated);
+        });
+    }
+}
diff --git a/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackRoutingHandler.java b/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackRoutingHandler.java
index 96a2c5b..0e2b46b 100644
--- a/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackRoutingHandler.java
+++ b/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackRoutingHandler.java
@@ -22,6 +22,8 @@
 import org.onlab.packet.IpAddress;
 import org.onlab.packet.IpPrefix;
 import org.onlab.packet.VlanId;
+import org.onosproject.cfg.ComponentConfigService;
+import org.onosproject.cfg.ConfigProperty;
 import org.onosproject.cluster.ClusterService;
 import org.onosproject.cluster.LeadershipService;
 import org.onosproject.cluster.NodeId;
@@ -65,6 +67,7 @@
 
 import static java.util.concurrent.Executors.newSingleThreadScheduledExecutor;
 import static org.onlab.util.Tools.groupedThreads;
+import static org.onosproject.openstacknetworking.api.Constants.ARP_BROADCAST_MODE;
 import static org.onosproject.openstacknetworking.api.Constants.OPENSTACK_NETWORKING_APP_ID;
 import static org.onosproject.openstacknetworking.api.Constants.PRIORITY_ADMIN_RULE;
 import static org.onosproject.openstacknetworking.api.Constants.PRIORITY_ICMP_RULE;
@@ -72,10 +75,10 @@
 import static org.onosproject.openstacknetworking.api.Constants.PRIORITY_SWITCHING_RULE;
 import static org.onosproject.openstacknetworking.api.Constants.ROUTING_TABLE;
 import static org.onosproject.openstacknetworking.api.Constants.STAT_OUTBOUND_TABLE;
-import static org.onosproject.openstacknetworking.api.OpenstackNetwork.Type.GENEVE;
-import static org.onosproject.openstacknetworking.api.OpenstackNetwork.Type.GRE;
-import static org.onosproject.openstacknetworking.api.OpenstackNetwork.Type.VLAN;
-import static org.onosproject.openstacknetworking.api.OpenstackNetwork.Type.VXLAN;
+import static org.onosproject.openstacknetworking.impl.OsgiPropertyConstants.ARP_MODE;
+import static org.onosproject.openstacknetworking.impl.OsgiPropertyConstants.USE_STATEFUL_SNAT;
+import static org.onosproject.openstacknetworking.util.OpenstackNetworkingUtil.getPropertyValue;
+import static org.onosproject.openstacknetworking.util.OpenstackNetworkingUtil.getPropertyValueAsBoolean;
 import static org.onosproject.openstacknetworking.util.OpenstackNetworkingUtil.tunnelPortNumByNetType;
 import static org.onosproject.openstacknetworking.util.RulePopulatorUtil.buildExtension;
 import static org.onosproject.openstacknode.api.OpenstackNode.NodeType.COMPUTE;
@@ -103,6 +106,9 @@
     protected ClusterService clusterService;
 
     @Reference(cardinality = ReferenceCardinality.MANDATORY)
+    protected ComponentConfigService configService;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY)
     protected OpenstackNodeService osNodeService;
 
     @Reference(cardinality = ReferenceCardinality.MANDATORY)
@@ -191,7 +197,7 @@
         }
 
         setInternalRoutes(osRouter, osSubnet, true);
-        setGatewayIcmp(osSubnet, osRouter, true);
+        setGatewayRules(osSubnet, osRouter, true);
         log.info("Connected subnet({}) to {}", osSubnet.getCidr(), osRouter.getName());
     }
 
@@ -212,11 +218,11 @@
         }
 
         setInternalRoutes(osRouter, osSubnet, false);
-        setGatewayIcmp(osSubnet, osRouter, false);
+        setGatewayRules(osSubnet, osRouter, false);
         log.info("Disconnected subnet({}) from {}", osSubnet.getCidr(), osRouter.getName());
     }
 
-    private void setGatewayIcmp(Subnet osSubnet, Router osRouter, boolean install) {
+    private void setGatewayRules(Subnet osSubnet, Router osRouter, boolean install) {
         OpenstackNode srcNatGw = osNodeService.completeNodes(GATEWAY)
                                          .stream().findFirst().orElse(null);
 
@@ -229,107 +235,33 @@
             return;
         }
 
-        // take ICMP request to a subnet gateway through gateway node group
         Network net = osNetworkAdminService.network(osSubnet.getNetworkId());
         Type netType = osNetworkAdminService.networkType(osSubnet.getNetworkId());
         Set<Subnet> routableSubnets = routableSubnets(osRouter, osSubnet.getId());
 
-        switch (netType) {
-            case VXLAN:
-                setGatewayIcmpForVxlan(osSubnet, srcNatGw, net, routableSubnets, install);
-                break;
-            case GRE:
-                setGatewayIcmpForGre(osSubnet, srcNatGw, net, routableSubnets, install);
-                break;
-            case GENEVE:
-                setGatewayIcmpForGeneve(osSubnet, srcNatGw, net, routableSubnets, install);
-                break;
-            case VLAN:
-                setGatewayIcmpForVlan(osSubnet, srcNatGw, net, routableSubnets, install);
-                break;
-            default:
-                final String error = String.format("%s %s", ERR_UNSUPPORTED_NET_TYPE,
-                                                            netType.toString());
-                throw new IllegalStateException(error);
+        // install rules to each compute node for routing IP packets to gateways
+        osNodeService.completeNodes(COMPUTE).stream()
+                .filter(cNode -> cNode.dataIp() != null)
+                .forEach(cNode -> setRulesToGatewayWithRoutableSubnets(
+                        cNode,
+                        srcNatGw,
+                        net.getProviderSegID(),
+                        osSubnet,
+                        routableSubnets,
+                        netType,
+                        install));
+
+        if (!getStatefulSnatFlag()) {
+            // install rules to punt ICMP packets to controller at gateway node
+            // this rule is only valid for stateless ICMP SNAT case
+            osNodeService.completeNodes(GATEWAY).forEach(gNode ->
+                    setReactiveGatewayIcmpRule(
+                            IpAddress.valueOf(osSubnet.getGateway()),
+                            gNode.intgBridge(), install));
         }
 
-        IpAddress gatewayIp = IpAddress.valueOf(osSubnet.getGateway());
-        osNodeService.completeNodes(GATEWAY).forEach(gNode ->
-            setGatewayIcmpRule(
-                    gatewayIp,
-                    gNode.intgBridge(),
-                    install));
-
         final String updateStr = install ? MSG_ENABLED : MSG_DISABLED;
-        log.debug(updateStr + "ICMP to {}", osSubnet.getGateway());
-    }
-
-    private void setGatewayIcmpForVxlan(Subnet osSubnet,
-                                        OpenstackNode srcNatGw,
-                                        Network network,
-                                        Set<Subnet> routableSubnets,
-                                        boolean install) {
-        osNodeService.completeNodes(COMPUTE).stream()
-                .filter(cNode -> cNode.dataIp() != null)
-                .forEach(cNode -> setRulesToGatewayWithRoutableSubnets(
-                        cNode,
-                        srcNatGw,
-                        network.getProviderSegID(),
-                        osSubnet,
-                        routableSubnets,
-                        VXLAN,
-                        install));
-    }
-
-    private void setGatewayIcmpForGre(Subnet osSubnet,
-                                      OpenstackNode srcNatGw,
-                                      Network network,
-                                      Set<Subnet> routableSubnets,
-                                      boolean install) {
-        osNodeService.completeNodes(COMPUTE).stream()
-                .filter(cNode -> cNode.dataIp() != null)
-                .forEach(cNode -> setRulesToGatewayWithRoutableSubnets(
-                        cNode,
-                        srcNatGw,
-                        network.getProviderSegID(),
-                        osSubnet,
-                        routableSubnets,
-                        GRE,
-                        install));
-    }
-
-    private void setGatewayIcmpForGeneve(Subnet osSubnet,
-                                         OpenstackNode srcNatGw,
-                                         Network network,
-                                         Set<Subnet> routableSubnets,
-                                         boolean install) {
-        osNodeService.completeNodes(COMPUTE).stream()
-                .filter(cNode -> cNode.dataIp() != null)
-                .forEach(cNode -> setRulesToGatewayWithRoutableSubnets(
-                        cNode,
-                        srcNatGw,
-                        network.getProviderSegID(),
-                        osSubnet,
-                        routableSubnets,
-                        GENEVE,
-                        install));
-    }
-
-    private void setGatewayIcmpForVlan(Subnet osSubnet,
-                                       OpenstackNode srcNatGw,
-                                       Network network,
-                                       Set<Subnet> routableSubnets,
-                                       boolean install) {
-        osNodeService.completeNodes(COMPUTE).stream()
-                .filter(cNode -> cNode.vlanPortNum() != null)
-                .forEach(cNode -> setRulesToGatewayWithRoutableSubnets(
-                        cNode,
-                        srcNatGw,
-                        network.getProviderSegID(),
-                        osSubnet,
-                        routableSubnets,
-                        VLAN,
-                        install));
+        log.debug(updateStr + "IP to {}", osSubnet.getGateway());
     }
 
     private void setInternalRoutes(Router osRouter, Subnet updatedSubnet, boolean install) {
@@ -393,7 +325,17 @@
         return osNetworkAdminService.network(osSubnet.getNetworkId()).getProviderSegID();
     }
 
-    private void setGatewayIcmpRule(IpAddress gatewayIp, DeviceId deviceId, boolean install) {
+    private boolean getStatefulSnatFlag() {
+        Set<ConfigProperty> properties = configService.getProperties(OpenstackRoutingSnatHandler.class.getName());
+        return getPropertyValueAsBoolean(properties, USE_STATEFUL_SNAT);
+    }
+
+    private String getArpMode() {
+        Set<ConfigProperty> properties = configService.getProperties(OpenstackRoutingArpHandler.class.getName());
+        return getPropertyValue(properties, ARP_MODE);
+    }
+
+    private void setReactiveGatewayIcmpRule(IpAddress gatewayIp, DeviceId deviceId, boolean install) {
         TrafficSelector selector = DefaultTrafficSelector.builder()
                 .matchEthType(Ethernet.TYPE_IPV4)
                 .matchIPProtocol(IPv4.PROTOCOL_ICMP)
@@ -546,7 +488,12 @@
                                                       Set<Subnet> routableSubnets,
                                                       Type networkType,
                                                       boolean install) {
-        //At first we install flow rules to gateway with segId and gatewayIp of updated subnet
+
+        if (getStatefulSnatFlag() && ARP_BROADCAST_MODE.equals(getArpMode())) {
+            return;
+        }
+
+        // at first we install flow rules to gateway with segId and gatewayIp of updated subnet
         setRulesToGatewayWithDstIp(osNode, sourceNatGateway, segmentId,
                 IpAddress.valueOf(updatedSubnet.getGateway()), networkType, install);
 
diff --git a/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackRoutingSnatHandler.java b/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackRoutingSnatHandler.java
index 212db1a..081c9bd 100644
--- a/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackRoutingSnatHandler.java
+++ b/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackRoutingSnatHandler.java
@@ -271,6 +271,11 @@
     }
 
     private void processSnatPacket(PacketContext context, Ethernet eth) {
+
+        if (useStatefulSnat) {
+            return;
+        }
+
         IPv4 iPacket = (IPv4) eth.getPayload();
         InboundPacket packetIn = context.inPacket();
 
@@ -822,7 +827,7 @@
         String netId = osNetworkAdminService.subnet(routerIface.getSubnetId()).getNetworkId();
 
         Map<OpenstackNode, PortRange> gwPortRangeMap = getAssignedPortsForGateway(
-                ImmutableList.copyOf(osNodeService.completeNodes(GATEWAY)));
+                ImmutableList.copyOf(osNodeService.nodes(GATEWAY)));
 
         osNodeService.completeNodes(GATEWAY)
                 .forEach(gwNode -> {
diff --git a/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackRoutingIcmpHandler.java b/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackRoutingSnatIcmpHandler.java
similarity index 95%
rename from apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackRoutingIcmpHandler.java
rename to apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackRoutingSnatIcmpHandler.java
index 977fe36..1e4d002 100644
--- a/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackRoutingIcmpHandler.java
+++ b/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackRoutingSnatIcmpHandler.java
@@ -24,6 +24,8 @@
 import org.onlab.packet.MacAddress;
 import org.onlab.packet.VlanId;
 import org.onlab.util.KryoNamespace;
+import org.onosproject.cfg.ComponentConfigService;
+import org.onosproject.cfg.ConfigProperty;
 import org.onosproject.cluster.ClusterService;
 import org.onosproject.cluster.LeadershipService;
 import org.onosproject.cluster.NodeId;
@@ -82,8 +84,10 @@
 import static org.onosproject.openstacknetworking.api.Constants.GW_COMMON_TABLE;
 import static org.onosproject.openstacknetworking.api.Constants.OPENSTACK_NETWORKING_APP_ID;
 import static org.onosproject.openstacknetworking.api.Constants.PRIORITY_INTERNAL_ROUTING_RULE;
+import static org.onosproject.openstacknetworking.impl.OsgiPropertyConstants.USE_STATEFUL_SNAT;
 import static org.onosproject.openstacknetworking.util.OpenstackNetworkingUtil.externalIpFromSubnet;
 import static org.onosproject.openstacknetworking.util.OpenstackNetworkingUtil.externalPeerRouterFromSubnet;
+import static org.onosproject.openstacknetworking.util.OpenstackNetworkingUtil.getPropertyValueAsBoolean;
 import static org.onosproject.openstacknode.api.OpenstackNode.NodeType.GATEWAY;
 import static org.slf4j.LoggerFactory.getLogger;
 
@@ -95,7 +99,7 @@
  * external connectivity.
  */
 @Component(immediate = true)
-public class OpenstackRoutingIcmpHandler {
+public class OpenstackRoutingSnatIcmpHandler {
 
     protected final Logger log = getLogger(getClass());
 
@@ -118,6 +122,9 @@
     protected InstancePortService instancePortService;
 
     @Reference(cardinality = ReferenceCardinality.MANDATORY)
+    protected ComponentConfigService configService;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY)
     protected OpenstackNetworkService osNetworkService;
 
     @Reference(cardinality = ReferenceCardinality.MANDATORY)
@@ -175,10 +182,15 @@
         log.info("Stopped");
     }
 
+    private boolean getStatefulSnatFlag() {
+        Set<ConfigProperty> properties = configService.getProperties(OpenstackRoutingSnatHandler.class.getName());
+        return getPropertyValueAsBoolean(properties, USE_STATEFUL_SNAT);
+    }
+
     private class InternalNodeEventListener implements OpenstackNodeListener {
         @Override
         public boolean isRelevant(OpenstackNodeEvent event) {
-            return event.subject().type() == GATEWAY;
+            return event.subject().type() == GATEWAY && !getStatefulSnatFlag();
         }
 
         private boolean isRelevantHelper() {
@@ -253,6 +265,10 @@
                     return;
                 }
 
+                if (getStatefulSnatFlag()) {
+                    return;
+                }
+
                 InboundPacket pkt = context.inPacket();
                 Ethernet ethernet = pkt.parsed();
                 if (ethernet == null || ethernet.getEtherType() != Ethernet.TYPE_IPV4) {
@@ -515,6 +531,7 @@
             switch (osNetworkService.networkType(netId)) {
                 case VXLAN:
                 case GRE:
+                case GENEVE:
                     tBuilder.setTunnelId(Long.valueOf(segId));
                     break;
                 case VLAN:
@@ -536,5 +553,4 @@
             return ((ICMPEcho) icmp.getPayload()).getIdentifier();
         }
     }
-
 }
diff --git a/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackSwitchingHandler.java b/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackSwitchingHandler.java
index 71dbe5a..b1d69bf 100644
--- a/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackSwitchingHandler.java
+++ b/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackSwitchingHandler.java
@@ -117,7 +117,6 @@
     protected ComponentConfigService configService;
 
     @Reference(cardinality = ReferenceCardinality.MANDATORY)
-
     protected LeadershipService leadershipService;
 
     @Reference(cardinality = ReferenceCardinality.MANDATORY)
diff --git a/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackSwitchingIcmpHandler.java b/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackSwitchingIcmpHandler.java
new file mode 100644
index 0000000..3f8a362
--- /dev/null
+++ b/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackSwitchingIcmpHandler.java
@@ -0,0 +1,324 @@
+/*
+ * Copyright 2019-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.openstacknetworking.impl;
+
+import com.google.common.collect.ImmutableSet;
+import org.onlab.packet.Ethernet;
+import org.onlab.packet.IPv4;
+import org.onlab.packet.IpAddress;
+import org.onlab.packet.VlanId;
+import org.onosproject.cfg.ComponentConfigService;
+import org.onosproject.cfg.ConfigProperty;
+import org.onosproject.cluster.ClusterService;
+import org.onosproject.cluster.LeadershipService;
+import org.onosproject.cluster.NodeId;
+import org.onosproject.core.ApplicationId;
+import org.onosproject.core.CoreService;
+import org.onosproject.mastership.MastershipService;
+import org.onosproject.net.Device;
+import org.onosproject.net.PortNumber;
+import org.onosproject.net.device.DeviceService;
+import org.onosproject.net.driver.DriverService;
+import org.onosproject.net.flow.DefaultTrafficSelector;
+import org.onosproject.net.flow.DefaultTrafficTreatment;
+import org.onosproject.net.flow.TrafficSelector;
+import org.onosproject.net.flow.TrafficTreatment;
+import org.onosproject.openstacknetworking.api.OpenstackFlowRuleService;
+import org.onosproject.openstacknetworking.api.OpenstackNetwork.Type;
+import org.onosproject.openstacknetworking.api.OpenstackNetworkService;
+import org.onosproject.openstacknetworking.api.OpenstackRouterEvent;
+import org.onosproject.openstacknetworking.api.OpenstackRouterListener;
+import org.onosproject.openstacknetworking.api.OpenstackRouterService;
+import org.onosproject.openstacknode.api.OpenstackNode;
+import org.onosproject.openstacknode.api.OpenstackNodeEvent;
+import org.onosproject.openstacknode.api.OpenstackNodeListener;
+import org.onosproject.openstacknode.api.OpenstackNodeService;
+import org.openstack4j.model.network.Router;
+import org.openstack4j.model.network.RouterInterface;
+import org.openstack4j.model.network.Subnet;
+import org.osgi.service.component.annotations.Activate;
+import org.osgi.service.component.annotations.Component;
+import org.osgi.service.component.annotations.Deactivate;
+import org.osgi.service.component.annotations.Reference;
+import org.osgi.service.component.annotations.ReferenceCardinality;
+import org.slf4j.Logger;
+
+import java.util.Objects;
+import java.util.Set;
+import java.util.concurrent.ExecutorService;
+import java.util.stream.Collectors;
+
+import static java.util.concurrent.Executors.newSingleThreadExecutor;
+import static org.onlab.packet.ICMP.CODE_ECHO_REQEUST;
+import static org.onlab.packet.ICMP.TYPE_ECHO_REPLY;
+import static org.onlab.packet.ICMP.TYPE_ECHO_REQUEST;
+import static org.onlab.util.Tools.groupedThreads;
+import static org.onosproject.openstacknetworking.api.Constants.DEFAULT_GATEWAY_MAC;
+import static org.onosproject.openstacknetworking.api.Constants.OPENSTACK_NETWORKING_APP_ID;
+import static org.onosproject.openstacknetworking.api.Constants.PRIORITY_ICMP_RULE;
+import static org.onosproject.openstacknetworking.api.Constants.ROUTING_TABLE;
+import static org.onosproject.openstacknetworking.impl.OsgiPropertyConstants.USE_STATEFUL_SNAT;
+import static org.onosproject.openstacknetworking.util.OpenstackNetworkingUtil.getPropertyValueAsBoolean;
+import static org.onosproject.openstacknetworking.util.RulePopulatorUtil.NXM_NX_IP_TTL;
+import static org.onosproject.openstacknetworking.util.RulePopulatorUtil.NXM_OF_ICMP_TYPE;
+import static org.onosproject.openstacknetworking.util.RulePopulatorUtil.buildLoadExtension;
+import static org.onosproject.openstacknetworking.util.RulePopulatorUtil.buildMoveEthSrcToDstExtension;
+import static org.onosproject.openstacknetworking.util.RulePopulatorUtil.buildMoveIpSrcToDstExtension;
+import static org.onosproject.openstacknode.api.OpenstackNode.NodeType.COMPUTE;
+import static org.slf4j.LoggerFactory.getLogger;
+
+/**
+ * Populates the ICMP flow rules for providing connectivity with gateways.
+ */
+@Component(immediate = true)
+public class OpenstackSwitchingIcmpHandler {
+
+    private final Logger log = getLogger(getClass());
+
+    private static final int DEFAULT_TTL = 0xff;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY)
+    protected CoreService coreService;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY)
+    protected MastershipService mastershipService;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY)
+    protected DeviceService deviceService;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY)
+    protected DriverService driverService;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY)
+    protected ClusterService clusterService;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY)
+    protected ComponentConfigService configService;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY)
+    protected LeadershipService leadershipService;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY)
+    protected OpenstackNodeService osNodeService;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY)
+    protected OpenstackNetworkService osNetworkService;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY)
+    protected OpenstackFlowRuleService osFlowRuleService;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY)
+    protected OpenstackRouterService osRouterService;
+
+    private final ExecutorService eventExecutor = newSingleThreadExecutor(
+            groupedThreads(this.getClass().getSimpleName(), "event-handler"));
+    private final OpenstackRouterListener osRouterListener = new InternalRouterEventListener();
+    private final OpenstackNodeListener osNodeListener = new InternalNodeEventListener();
+
+    private ApplicationId appId;
+    private NodeId localNodeId;
+
+    @Activate
+    protected void activate() {
+        appId = coreService.registerApplication(OPENSTACK_NETWORKING_APP_ID);
+        localNodeId = clusterService.getLocalNode().id();
+        osRouterService.addListener(osRouterListener);
+        osNodeService.addListener(osNodeListener);
+
+        log.info("Started");
+    }
+
+    @Deactivate
+    protected void deactivate() {
+        osRouterService.removeListener(osRouterListener);
+        osNodeService.removeListener(osNodeListener);
+        eventExecutor.shutdown();
+
+        log.info("Stopped");
+    }
+
+    private boolean getStatefulSnatFlag() {
+        Set<ConfigProperty> properties =
+                configService.getProperties(OpenstackRoutingSnatHandler.class.getName());
+        return getPropertyValueAsBoolean(properties, USE_STATEFUL_SNAT);
+    }
+
+    private void processRouterIntfEvent(Router osRouter, RouterInterface routerIface, boolean install) {
+        if (!getStatefulSnatFlag()) {
+            return;
+        }
+
+        Subnet osSubnet = osNetworkService.subnet(routerIface.getSubnetId());
+        Type netType = osNetworkService.networkType(osSubnet.getNetworkId());
+        String segId = osNetworkService.segmentId(osSubnet.getNetworkId());
+        IpAddress gatewayIp = IpAddress.valueOf(osSubnet.getGateway());
+        Set<Subnet> routableSubnets = routableSubnets(osRouter, osSubnet.getId());
+
+        osNodeService.completeNodes(COMPUTE).stream()
+                .filter(cNode -> cNode.dataIp() != null)
+                .forEach(cNode -> setRoutableSubnetsIcmpRules(
+                        cNode, segId, routableSubnets, gatewayIp, netType, install));
+    }
+
+    private void setRoutableSubnetsIcmpRules(OpenstackNode osNode,
+                                             String segmentId,
+                                             Set<Subnet> routableSubnets,
+                                             IpAddress gatewayIp,
+                                             Type networkType,
+                                             boolean install) {
+        setGatewayIcmpReplyRule(osNode, segmentId, gatewayIp, networkType, install);
+
+        routableSubnets.forEach(subnet -> {
+            setGatewayIcmpReplyRule(osNode, segmentId,
+                    IpAddress.valueOf(subnet.getGateway()), networkType, install);
+        });
+    }
+
+    private Set<Subnet> routableSubnets(Router osRouter, String osSubnetId) {
+        Set<Subnet> osSubnets = osRouterService.routerInterfaces(osRouter.getId())
+                .stream()
+                .filter(iface -> !Objects.equals(iface.getSubnetId(), osSubnetId))
+                .map(iface -> osNetworkService.subnet(iface.getSubnetId()))
+                .collect(Collectors.toSet());
+        return ImmutableSet.copyOf(osSubnets);
+    }
+
+    private void setGatewayIcmpReplyRule(OpenstackNode osNode,
+                                         String segmentId,
+                                         IpAddress gatewayIp,
+                                         Type networkType,
+                                         boolean install) {
+        TrafficSelector.Builder sBuilder = DefaultTrafficSelector.builder()
+                .matchEthType(Ethernet.TYPE_IPV4)
+                .matchIPProtocol(IPv4.PROTOCOL_ICMP)
+                .matchIcmpType(TYPE_ECHO_REQUEST)
+                .matchIcmpCode(CODE_ECHO_REQEUST)
+                .matchIPDst(gatewayIp.getIp4Address().toIpPrefix());
+
+        switch (networkType) {
+            case VXLAN:
+            case GRE:
+            case GENEVE:
+                sBuilder.matchTunnelId(Long.parseLong(segmentId));
+                break;
+            case VLAN:
+                sBuilder.matchVlanId(VlanId.vlanId(segmentId));
+                break;
+            default:
+                break;
+        }
+
+        Device device = deviceService.getDevice(osNode.intgBridge());
+        TrafficTreatment.Builder tBuilder = DefaultTrafficTreatment.builder()
+                .extension(buildMoveEthSrcToDstExtension(device), device.id())
+                .extension(buildMoveIpSrcToDstExtension(device), device.id())
+                .extension(buildLoadExtension(device, NXM_NX_IP_TTL, DEFAULT_TTL), device.id())
+                .extension(buildLoadExtension(device, NXM_OF_ICMP_TYPE, TYPE_ECHO_REPLY), device.id())
+                .setIpSrc(gatewayIp)
+                .setEthSrc(DEFAULT_GATEWAY_MAC)
+                .setOutput(PortNumber.IN_PORT);
+
+        osFlowRuleService.setRule(
+                appId,
+                osNode.intgBridge(),
+                sBuilder.build(),
+                tBuilder.build(),
+                PRIORITY_ICMP_RULE,
+                ROUTING_TABLE,
+                install);
+    }
+
+    private class InternalRouterEventListener implements OpenstackRouterListener {
+        private boolean isRelevantHelper() {
+            return Objects.equals(localNodeId, leadershipService.getLeader(appId.name()));
+        }
+
+        @Override
+        public void event(OpenstackRouterEvent event) {
+            switch (event.type()) {
+                case OPENSTACK_ROUTER_INTERFACE_ADDED:
+                    eventExecutor.execute(() -> processRouterIntfCreation(event));
+                    break;
+                case OPENSTACK_ROUTER_INTERFACE_REMOVED:
+                    eventExecutor.execute(() -> processRouterIntfRemoval(event));
+                    break;
+                default:
+                    // do nothing for the other events
+                    break;
+            }
+        }
+
+        private void processRouterIntfCreation(OpenstackRouterEvent event) {
+            if (!isRelevantHelper()) {
+                return;
+            }
+
+            log.debug("Router interface {} added to router {}",
+                    event.routerIface().getPortId(),
+                    event.routerIface().getId());
+
+            processRouterIntfEvent(event.subject(), event.routerIface(), true);
+        }
+
+        private void processRouterIntfRemoval(OpenstackRouterEvent event) {
+            if (!isRelevantHelper()) {
+                return;
+            }
+
+            log.debug("Router interface {} removed from router {}",
+                    event.routerIface().getPortId(),
+                    event.routerIface().getId());
+
+            processRouterIntfEvent(event.subject(), event.routerIface(), false);
+        }
+    }
+
+    private class InternalNodeEventListener implements OpenstackNodeListener {
+
+        private boolean isRelevantHelper() {
+            return Objects.equals(localNodeId, leadershipService.getLeader(appId.name()));
+        }
+
+        @Override
+        public void event(OpenstackNodeEvent event) {
+            OpenstackNode osNode = event.subject();
+            switch (event.type()) {
+                case OPENSTACK_NODE_COMPLETE:
+                case OPENSTACK_NODE_INCOMPLETE:
+                case OPENSTACK_NODE_UPDATED:
+                case OPENSTACK_NODE_REMOVED:
+                    eventExecutor.execute(() -> {
+                        if (!isRelevantHelper()) {
+                            return;
+                        }
+                        reconfigureRouters(osNode);
+                    });
+                    break;
+                default:
+                    break;
+            }
+        }
+
+        private void reconfigureRouters(OpenstackNode osNode) {
+            osRouterService.routers().forEach(osRouter -> {
+                osRouterService.routerInterfaces(osRouter.getId()).forEach(iface -> {
+                    processRouterIntfEvent(osRouter, iface, true);
+                });
+            });
+            log.info("Reconfigure routers for {}", osNode.hostname());
+        }
+    }
+}
diff --git a/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/util/RulePopulatorUtil.java b/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/util/RulePopulatorUtil.java
index dace1ff..77a66ab 100644
--- a/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/util/RulePopulatorUtil.java
+++ b/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/util/RulePopulatorUtil.java
@@ -35,6 +35,11 @@
 import java.util.ArrayList;
 import java.util.List;
 
+import static org.onosproject.net.flow.instructions.ExtensionTreatmentType.ExtensionTreatmentTypes.NICIRA_LOAD;
+import static org.onosproject.net.flow.instructions.ExtensionTreatmentType.ExtensionTreatmentTypes.NICIRA_MOV_ETH_SRC_TO_DST;
+import static org.onosproject.net.flow.instructions.ExtensionTreatmentType.ExtensionTreatmentTypes.NICIRA_MOV_IP_SRC_TO_DST;
+import static org.onosproject.net.flow.instructions.ExtensionTreatmentType.ExtensionTreatmentTypes.NICIRA_POP_NSH;
+import static org.onosproject.net.flow.instructions.ExtensionTreatmentType.ExtensionTreatmentTypes.NICIRA_PUSH_NSH;
 import static org.onosproject.net.flow.instructions.ExtensionTreatmentType.ExtensionTreatmentTypes.NICIRA_SET_TUNNEL_DST;
 import static org.slf4j.LoggerFactory.getLogger;
 
@@ -78,6 +83,36 @@
     public static final long CT_STATE_NOT_TRK = 0x20;
     public static final long CT_STATE_TRK = 0x20;
 
+    private static final String OFF_SET_N_BITS = "ofsNbits";
+    private static final String DESTINATION = "dst";
+    private static final String VALUE = "value";
+
+    private static final int OFF_SET_BIT = 0;
+    private static final int REMAINDER_BIT = 8;
+
+    // layer 3 nicira fields
+    public static final int NXM_OF_IP_SRC = 0x00000e04;
+    public static final int NXM_OF_IP_DST = 0x00001004;
+    public static final int NXM_OF_IP_PROT = 0x00000c01;
+
+    public static final int NXM_NX_IP_TTL = 0x00013a01;
+    public static final int NXM_NX_IP_FRAG = 0x00013401;
+    public static final int NXM_OF_ARP_OP = 0x00001e02;
+    public static final int NXM_OF_ARP_SPA = 0x00002004;
+    public static final int NXM_OF_ARP_TPA = 0x00002204;
+    public static final int NXM_NX_ARP_SHA = 0x00012206;
+    public static final int NXM_NX_ARP_THA = 0x00012406;
+
+    // layer 4 nicira fields
+    public static final int NXM_OF_TCP_SRC = 0x00001202;
+    public static final int NXM_OF_TCP_DST = 0x00001402;
+    public static final int NXM_NX_TCP_FLAGS = 0x00014402;
+    public static final int NXM_OF_UDP_SRC = 0x00001602;
+    public static final int NXM_OF_UDP_DST = 0x00001802;
+
+    public static final int NXM_OF_ICMP_TYPE = 0x00001a01;
+    public static final int NXM_OF_ICMP_CODE = 0x00001c01;
+
     private RulePopulatorUtil() {
     }
 
@@ -157,6 +192,104 @@
     }
 
     /**
+     * Returns the nicira load extension treatment.
+     *
+     * @param device        device instance
+     * @param field         field code
+     * @param value         value to load
+     * @return load extension treatment
+     */
+    public static ExtensionTreatment buildLoadExtension(Device device,
+                                                        long field,
+                                                        long value) {
+        if (device == null || !device.is(ExtensionTreatmentResolver.class)) {
+            log.warn("Nicira extension treatment is not supported");
+            return null;
+        }
+
+        ExtensionTreatmentResolver resolver = device.as(ExtensionTreatmentResolver.class);
+        ExtensionTreatment treatment =
+                resolver.getExtensionInstruction(NICIRA_LOAD.type());
+
+        int ofsNbits = OFF_SET_BIT << 6 | (REMAINDER_BIT - 1);
+
+        try {
+            treatment.setPropertyValue(OFF_SET_N_BITS, ofsNbits);
+            treatment.setPropertyValue(DESTINATION, field);
+            treatment.setPropertyValue(VALUE, value);
+            return treatment;
+        } catch (ExtensionPropertyException e) {
+            log.error("Failed to set nicira load extension treatment for {}",
+                    device.id());
+            return null;
+        }
+    }
+
+    /**
+     * Returns the nicira push extension treatment.
+     *
+     * @param device        device instance
+     * @return push extension treatment
+     */
+    public static ExtensionTreatment buildPushExtension(Device device) {
+        if (device == null || !device.is(ExtensionTreatmentResolver.class)) {
+            log.warn("Nicira extension treatment is not supported");
+            return null;
+        }
+
+        ExtensionTreatmentResolver resolver = device.as(ExtensionTreatmentResolver.class);
+        return resolver.getExtensionInstruction(NICIRA_PUSH_NSH.type());
+    }
+
+    /**
+     * Returns the nicira pop extension treatment.
+     *
+     * @param device        device instance
+     * @return pop extension treatment
+     */
+    public static ExtensionTreatment buildPopExtension(Device device) {
+        if (device == null || !device.is(ExtensionTreatmentResolver.class)) {
+            log.warn("Nicira extension treatment is not supported");
+            return null;
+        }
+
+        ExtensionTreatmentResolver resolver = device.as(ExtensionTreatmentResolver.class);
+        return resolver.getExtensionInstruction(NICIRA_POP_NSH.type());
+    }
+
+    /**
+     * Returns the nicira move source MAC to destination MAC extension treatment.
+     *
+     * @param device        device instance
+     * @return move extension treatment
+     */
+    public static ExtensionTreatment buildMoveEthSrcToDstExtension(Device device) {
+        if (device == null || !device.is(ExtensionTreatmentResolver.class)) {
+            log.warn("Nicira extension treatment is not supported");
+            return null;
+        }
+
+        ExtensionTreatmentResolver resolver = device.as(ExtensionTreatmentResolver.class);
+        return resolver.getExtensionInstruction(NICIRA_MOV_ETH_SRC_TO_DST.type());
+    }
+
+    /**
+     * Returns the nicira move source IP to destination IP extension treatment.
+     *
+     * @param device        device instance
+     * @return move extension treatment
+     */
+    public static ExtensionTreatment buildMoveIpSrcToDstExtension(Device device) {
+        if (device == null || !device.is(ExtensionTreatmentResolver.class)) {
+            log.warn("Nicira extension treatment is not supported");
+            return null;
+        }
+
+        ExtensionTreatmentResolver resolver = device.as(ExtensionTreatmentResolver.class);
+        return resolver.getExtensionInstruction(NICIRA_MOV_IP_SRC_TO_DST.type());
+    }
+
+    /**
      * Computes ConnTack State flag values.
      *
      * @param isTracking true for +trk, false for -trk
diff --git a/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/web/OpenstackManagementWebResource.java b/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/web/OpenstackManagementWebResource.java
index febcb7a..115f66c 100644
--- a/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/web/OpenstackManagementWebResource.java
+++ b/apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/web/OpenstackManagementWebResource.java
@@ -29,6 +29,7 @@
 import org.onosproject.openstacknetworking.api.OpenstackRouterAdminService;
 import org.onosproject.openstacknetworking.api.OpenstackSecurityGroupAdminService;
 import org.onosproject.openstacknetworking.impl.OpenstackRoutingArpHandler;
+import org.onosproject.openstacknetworking.impl.OpenstackRoutingSnatHandler;
 import org.onosproject.openstacknetworking.impl.OpenstackSecurityGroupHandler;
 import org.onosproject.openstacknetworking.impl.OpenstackSwitchingArpHandler;
 import org.onosproject.openstacknetworking.util.OpenstackNetworkingUtil;
@@ -61,6 +62,7 @@
 import static org.onosproject.openstacknetworking.util.OpenstackNetworkingUtil.checkActivationFlag;
 import static org.onosproject.openstacknetworking.util.OpenstackNetworkingUtil.checkArpMode;
 import static org.onosproject.openstacknetworking.util.OpenstackNetworkingUtil.getPropertyValue;
+import static org.onosproject.openstacknetworking.util.OpenstackNetworkingUtil.getPropertyValueAsBoolean;
 import static org.onosproject.openstacknode.api.NodeState.COMPLETE;
 import static org.onosproject.openstacknode.api.OpenstackNode.NodeType.COMPUTE;
 import static org.onosproject.openstacknode.api.OpenstackNode.NodeType.CONTROLLER;
@@ -76,6 +78,7 @@
     private static final String FLOATINGIPS = "floatingips";
     private static final String ARP_MODE_NAME = "arpMode";
     private static final String USE_SECURITY_GROUP_NAME = "useSecurityGroup";
+    private static final String USE_STATEFUL_SNAT_NAME = "useStatefulSnat";
 
     private static final long SLEEP_MS = 3000; // we wait 3s for init each node
     private static final long TIMEOUT_MS = 10000; // we wait 10s
@@ -83,6 +86,7 @@
     private static final String DEVICE_OWNER_IFACE = "network:router_interface";
 
     private static final String ARP_MODE_REQUIRED = "ARP mode is not specified";
+    private static final String STATEFUL_SNAT_REQUIRED = "Stateful SNAT flag nis not specified";
 
     private static final String SECURITY_GROUP_FLAG_REQUIRED = "Security Group flag is not specified";
 
@@ -273,6 +277,39 @@
     }
 
     /**
+     * Configures the stateful SNAT flag (enable | disable).
+     *
+     * @param statefulSnat stateful SNAT flag
+     * @return 200 OK with config result, 404 not found
+     */
+    @GET
+    @Produces(MediaType.APPLICATION_JSON)
+    @Path("config/statefulSnat/{statefulSnat}")
+    public Response configStatefulSnat(@PathParam("statefulSnat") String statefulSnat) {
+        String statefulSnatStr = nullIsIllegal(statefulSnat, STATEFUL_SNAT_REQUIRED);
+        boolean flag = checkActivationFlag(statefulSnatStr);
+        configStatefulSnatBase(flag);
+
+        ComponentConfigService service = get(ComponentConfigService.class);
+        String snatComponent = OpenstackRoutingSnatHandler.class.getName();
+
+        while (true) {
+            boolean snatValue =
+                    getPropertyValueAsBoolean(
+                            service.getProperties(snatComponent), USE_STATEFUL_SNAT_NAME);
+
+            if (flag == snatValue) {
+                break;
+            }
+        }
+
+        purgeRulesBase();
+        syncRulesBase();
+
+        return ok(mapper().createObjectNode()).build();
+    }
+
+    /**
      * Configures the security group (enable | disable).
      *
      * @param securityGroup security group activation flag
@@ -433,4 +470,11 @@
         service.setProperty(switchingComponent, ARP_MODE_NAME, arpMode);
         service.setProperty(routingComponent, ARP_MODE_NAME, arpMode);
     }
+
+    private void configStatefulSnatBase(boolean snatFlag) {
+        ComponentConfigService service = get(ComponentConfigService.class);
+        String snatComponent = OpenstackRoutingSnatHandler.class.getName();
+
+        service.setProperty(snatComponent, USE_STATEFUL_SNAT_NAME, String.valueOf(snatFlag));
+    }
 }
diff --git a/apps/openstacknetworking/app/src/test/java/org/onosproject/openstacknetworking/impl/OpenstackRoutingIcmpHandlerTest.java b/apps/openstacknetworking/app/src/test/java/org/onosproject/openstacknetworking/impl/OpenstackRoutingSnatIcmpHandlerTest.java
similarity index 97%
rename from apps/openstacknetworking/app/src/test/java/org/onosproject/openstacknetworking/impl/OpenstackRoutingIcmpHandlerTest.java
rename to apps/openstacknetworking/app/src/test/java/org/onosproject/openstacknetworking/impl/OpenstackRoutingSnatIcmpHandlerTest.java
index b7c4e7b..e4846ad 100644
--- a/apps/openstacknetworking/app/src/test/java/org/onosproject/openstacknetworking/impl/OpenstackRoutingIcmpHandlerTest.java
+++ b/apps/openstacknetworking/app/src/test/java/org/onosproject/openstacknetworking/impl/OpenstackRoutingSnatIcmpHandlerTest.java
@@ -74,8 +74,8 @@
 import static org.onlab.packet.ICMP.TYPE_ECHO_REQUEST;
 import static org.onosproject.net.NetTestTools.connectPoint;
 
-public class OpenstackRoutingIcmpHandlerTest {
-    private OpenstackRoutingIcmpHandler icmpHandler;
+public class OpenstackRoutingSnatIcmpHandlerTest {
+    private OpenstackRoutingSnatIcmpHandler icmpHandler;
     private static final byte CODE_ECHO_REQUEST = 0x00;
     private static final byte CODE_ECHO_REPLY = 0x00;
 
@@ -110,7 +110,7 @@
     @Before
     public void setUp() {
 
-        icmpHandler = new OpenstackRoutingIcmpHandler();
+        icmpHandler = new OpenstackRoutingSnatIcmpHandler();
 
         icmpHandler.coreService = new TestCoreService();
         icmpHandler.packetService = new TestPacketService();
@@ -433,11 +433,11 @@
 
 
     private void createPort() {
-        InputStream portJsonStream1 = OpenstackRoutingIcmpHandlerTest.class
+        InputStream portJsonStream1 = OpenstackRoutingSnatIcmpHandlerTest.class
                 .getResourceAsStream("openstack-port-1.json");
         port1 = (Port) OpenstackNetworkingUtil.jsonToModelEntity(portJsonStream1, NeutronPort.class);
 
-        InputStream portJsonStream2 = OpenstackRoutingIcmpHandlerTest.class
+        InputStream portJsonStream2 = OpenstackRoutingSnatIcmpHandlerTest.class
                 .getResourceAsStream("openstack-port-external.json");
         externalPort = (Port) OpenstackNetworkingUtil.jsonToModelEntity(portJsonStream2, NeutronPort.class);
 
@@ -447,7 +447,7 @@
     }
 
     private void createSubnet() {
-        InputStream subnetJsonStream1 = OpenstackRoutingIcmpHandlerTest.class
+        InputStream subnetJsonStream1 = OpenstackRoutingSnatIcmpHandlerTest.class
                 .getResourceAsStream("openstack-subnet-1.json");
         subnet1 = (Subnet) OpenstackNetworkingUtil.jsonToModelEntity(subnetJsonStream1, NeutronSubnet.class);
     }
@@ -462,7 +462,7 @@
     }
 
     private void createRouterMap() {
-        InputStream routerStream1 = OpenstackRoutingIcmpHandlerTest.class
+        InputStream routerStream1 = OpenstackRoutingSnatIcmpHandlerTest.class
                 .getResourceAsStream("openstack-router-1.json");
         router1 = (Router)
                 OpenstackNetworkingUtil.jsonToModelEntity(routerStream1, NeutronRouter.class);