Implement SFC integration
[groupbasedpolicy.git] / renderers / ofoverlay / src / main / java / org / opendaylight / groupbasedpolicy / renderer / ofoverlay / flow / DestinationMapper.java
index 4dfefdbc79cf62070fb3fcfe167324f4acf03eb8..dc8e608c1a371ee0d863380c992e32ad531de8ab 100644 (file)
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2014 Cisco Systems, Inc. and others.  All rights reserved.
+ * Copyright (c) 2014 Cisco Systems, Inc. and others. All rights reserved.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
@@ -25,24 +25,30 @@ import static org.opendaylight.groupbasedpolicy.renderer.ofoverlay.flow.FlowUtil
 import static org.opendaylight.groupbasedpolicy.renderer.ofoverlay.flow.FlowUtils.nxLoadArpSpaAction;
 import static org.opendaylight.groupbasedpolicy.renderer.ofoverlay.flow.FlowUtils.nxLoadRegAction;
 import static org.opendaylight.groupbasedpolicy.renderer.ofoverlay.flow.FlowUtils.nxLoadTunIPv4Action;
+import static org.opendaylight.groupbasedpolicy.renderer.ofoverlay.flow.FlowUtils.nxLoadTunIdAction;
 import static org.opendaylight.groupbasedpolicy.renderer.ofoverlay.flow.FlowUtils.nxMoveArpShaToArpThaAction;
 import static org.opendaylight.groupbasedpolicy.renderer.ofoverlay.flow.FlowUtils.nxMoveArpSpaToArpTpaAction;
 import static org.opendaylight.groupbasedpolicy.renderer.ofoverlay.flow.FlowUtils.nxMoveEthSrcToEthDstAction;
-import static org.opendaylight.groupbasedpolicy.renderer.ofoverlay.flow.FlowUtils.nxMoveRegTunIdAction;
 import static org.opendaylight.groupbasedpolicy.renderer.ofoverlay.flow.FlowUtils.outputAction;
 import static org.opendaylight.groupbasedpolicy.renderer.ofoverlay.flow.FlowUtils.setDlDstAction;
 import static org.opendaylight.groupbasedpolicy.renderer.ofoverlay.flow.FlowUtils.setDlSrcAction;
 
 import java.math.BigInteger;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
 import java.util.Objects;
 import java.util.Set;
 
 import org.opendaylight.controller.md.sal.binding.api.ReadOnlyTransaction;
+import org.opendaylight.controller.md.sal.binding.api.ReadTransaction;
 import org.opendaylight.controller.md.sal.common.api.data.LogicalDatastoreType;
+import org.opendaylight.controller.md.sal.common.api.data.ReadFailedException;
 import org.opendaylight.groupbasedpolicy.endpoint.EpKey;
 import org.opendaylight.groupbasedpolicy.renderer.ofoverlay.OfContext;
 import org.opendaylight.groupbasedpolicy.renderer.ofoverlay.PolicyManager.FlowMap;
@@ -50,6 +56,7 @@ import org.opendaylight.groupbasedpolicy.renderer.ofoverlay.flow.FlowUtils.RegMa
 import org.opendaylight.groupbasedpolicy.renderer.ofoverlay.flow.OrdinalFactory.EndpointFwdCtxOrdinals;
 import org.opendaylight.groupbasedpolicy.resolver.EgKey;
 import org.opendaylight.groupbasedpolicy.resolver.PolicyInfo;
+import org.opendaylight.groupbasedpolicy.resolver.TenantUtils;
 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev100924.IpAddress;
 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev100924.Ipv4Prefix;
 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev100924.Ipv6Prefix;
@@ -64,10 +71,18 @@ import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.types.rev131026.flow.M
 import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.types.rev131026.instruction.list.Instruction;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.flow.types.rev131026.instruction.list.InstructionBuilder;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.group.types.rev131018.groups.Group;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.common.rev140421.EndpointGroupId;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.common.rev140421.NetworkDomainId;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.common.rev140421.TenantId;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.endpoint.rev140421.Endpoints;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.endpoint.rev140421.endpoint.fields.L3Address;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.endpoint.rev140421.endpoints.Endpoint;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.endpoint.rev140421.endpoints.EndpointL3;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.endpoint.rev140421.endpoints.EndpointL3Key;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.ofoverlay.rev140528.EndpointLocation.LocationType;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.ofoverlay.rev140528.OfOverlayContext;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.policy.rev140421.tenants.Tenant;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.policy.rev140421.tenants.tenant.L3Context;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.groupbasedpolicy.policy.rev140421.tenants.tenant.Subnet;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.NodeConnectorId;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.inventory.rev130819.NodeId;
@@ -78,130 +93,160 @@ import org.opendaylight.yang.gen.v1.urn.opendaylight.model.match.types.rev131026
 import org.opendaylight.yang.gen.v1.urn.opendaylight.model.match.types.rev131026.match.layer._3.match.ArpMatchBuilder;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.model.match.types.rev131026.match.layer._3.match.Ipv4MatchBuilder;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.model.match.types.rev131026.match.layer._3.match.Ipv6MatchBuilder;
-import org.opendaylight.yang.gen.v1.urn.opendaylight.openflowjava.nx.match.rev140421.NxmNxReg0;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.openflowjava.nx.match.rev140421.NxmNxReg2;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.openflowjava.nx.match.rev140421.NxmNxReg3;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.openflowjava.nx.match.rev140421.NxmNxReg4;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.openflowjava.nx.match.rev140421.NxmNxReg5;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.openflowjava.nx.match.rev140421.NxmNxReg6;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.openflowjava.nx.match.rev140421.NxmNxReg7;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.overlay.rev150105.TunnelTypeVxlan;
+import org.opendaylight.yangtools.yang.binding.DataObject;
 import org.opendaylight.yangtools.yang.binding.InstanceIdentifier;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import com.google.common.base.Optional;
 import com.google.common.collect.HashMultimap;
-import com.google.common.collect.Multimap;
+import com.google.common.collect.SetMultimap;
 import com.google.common.collect.Sets;
+import com.google.common.util.concurrent.CheckedFuture;
 
 /**
  * Manage the table that maps the destination address to the next hop for the
  * path as well as applies any relevant routing transformations.
- *
  */
 public class DestinationMapper extends FlowTable {
-    protected static final Logger LOG =
-            LoggerFactory.getLogger(DestinationMapper.class);
 
-    //TODO Li alagalah: Improve UT coverage for this class.
+    protected static final Logger LOG = LoggerFactory.getLogger(DestinationMapper.class);
+
+    // TODO Li alagalah: Improve UT coverage for this class.
 
-    //TODO Li alagalah: Use EndpointL3 for L3 flows, Endpoint for L2 flows
+    // TODO Li alagalah: Use EndpointL3 for L3 flows, Endpoint for L2 flows
     // This ensures we have the appropriate network-containment'
 
     public static final short TABLE_ID = 2;
     /**
      * This is the MAC address of the magical router in the sky
      */
-    public static final MacAddress ROUTER_MAC =
-            new MacAddress("88:f0:31:b5:12:b5");
-    public static final MacAddress MULTICAST_MAC =
-            new MacAddress("01:00:00:00:00:00");
+    public static final MacAddress ROUTER_MAC = new MacAddress("88:f0:31:b5:12:b5");
+    public static final MacAddress MULTICAST_MAC = new MacAddress("01:00:00:00:00:00");
 
     public DestinationMapper(OfContext ctx) {
         super(ctx);
     }
 
+    Map<TenantId, HashSet<Subnet>> subnetsByTenant = new HashMap<TenantId, HashSet<Subnet>>();
+
     @Override
     public short getTableId() {
         return TABLE_ID;
     }
 
     @Override
-    public void sync(NodeId nodeId, PolicyInfo policyInfo, FlowMap flowMap)
-            throws Exception {
-
-        flowMap.writeFlow(nodeId,TABLE_ID,dropFlow(Integer.valueOf(1), null));
-
-        Set<EpKey> visitedEps = new HashSet<>();
-        Multimap<Integer,Subnet> subnetsByL3c = HashMultimap.create();
-        Set<Integer> fdIds = new HashSet<>();
-
-        for (EgKey epg : ctx.getEndpointManager().getGroupsForNode(nodeId)) {
-            Set<EgKey> peers = Sets.union(Collections.singleton(epg),
-                    policyInfo.getPeers(epg));
-            for (EgKey peer : peers) {
-                for(Endpoint epPeer : ctx.getEndpointManager().getEndpointsForGroup(peer)) {
-                    syncEP(flowMap, nodeId, policyInfo, epPeer, visitedEps);
-
-                    //Process subnets and flood-domains for epPeer
-                    EndpointFwdCtxOrdinals epOrds = OrdinalFactory.getEndpointFwdCtxOrdinals(ctx, policyInfo, epPeer);
-
-                    subnetsByL3c.putAll(epOrds.getL3Id(),ctx.getPolicyResolver().getTenant(peer.getTenantId()).resolveSubnets(epOrds.getNetworkContainment()));
-                    fdIds.add(epOrds.getFdId());
+    public void sync(NodeId nodeId, PolicyInfo policyInfo, FlowMap flowMap) throws Exception {
+
+        TenantId currentTenant;
+
+        flowMap.writeFlow(nodeId, TABLE_ID, dropFlow(Integer.valueOf(1), null));
+
+        SetMultimap<EpKey, EpKey> visitedEps = HashMultimap.create();
+        Set<EndpointFwdCtxOrdinals> epOrdSet = new HashSet<>();
+
+        for (Endpoint srcEp : ctx.getEndpointManager().getEndpointsForNode(nodeId)) {
+            Set<EndpointGroupId> srcEpgIds = new HashSet<>();
+            if (srcEp.getEndpointGroup() != null)
+                srcEpgIds.add(srcEp.getEndpointGroup());
+            if (srcEp.getEndpointGroups() != null)
+                srcEpgIds.addAll(srcEp.getEndpointGroups());
+
+            for (EndpointGroupId epgId : srcEpgIds) {
+                EgKey epg = new EgKey(srcEp.getTenant(), epgId);
+                Set<EgKey> peers = Sets.union(Collections.singleton(epg), policyInfo.getPeers(epg));
+                for (EgKey peer : peers) {
+                    for (Endpoint peerEp : ctx.getEndpointManager().getEndpointsForGroup(peer)) {
+                        currentTenant = peerEp.getTenant();
+                        subnetsByTenant.put(currentTenant, getSubnets(currentTenant));
+                        EpKey srcEpKey = new EpKey(srcEp.getL2Context(), srcEp.getMacAddress());
+                        EpKey peerEpKey = new EpKey(peerEp.getL2Context(), peerEp.getMacAddress());
+
+                        if (visitedEps.get(srcEpKey) != null && visitedEps.get(srcEpKey).contains(peerEpKey)) {
+                            continue;
+                        }
+                        syncEP(flowMap, nodeId, policyInfo, srcEp, peerEp);
+                        visitedEps.put(srcEpKey, peerEpKey);
+
+                        // Process subnets and flood-domains for epPeer
+                        EndpointFwdCtxOrdinals epOrds = OrdinalFactory.getEndpointFwdCtxOrdinals(ctx, policyInfo,
+                                peerEp);
+                        epOrdSet.add(epOrds);
+                    }
                 }
             }
         }
-        // Write subnet flows
-        for (Integer subnetKey : subnetsByL3c.keySet()) {
-            for(Subnet sn:subnetsByL3c.get(subnetKey)) {
-                flowMap.writeFlow(nodeId, TABLE_ID, createRouterArpFlow(nodeId, sn, subnetKey));
+
+        for (Entry<TenantId, HashSet<Subnet>> subnetEntry : subnetsByTenant.entrySet()) {
+            if (subnetEntry.getValue() == null) {
+                LOG.trace("Tenant: {} has empty subnet entry.", subnetEntry.getKey());
+                continue;
+            }
+            currentTenant = subnetEntry.getKey();
+            for (Subnet sn : subnetEntry.getValue()) {
+                L3Context l3c = getL3ContextForSubnet(currentTenant, sn);
+                Flow arpFlow = createRouterArpFlow(currentTenant, nodeId, sn,
+                        OrdinalFactory.getContextOrdinal(currentTenant, l3c.getId()));
+                if (arpFlow != null) {
+                    flowMap.writeFlow(nodeId, TABLE_ID, arpFlow);
+                } else {
+                    LOG.debug(
+                            "Gateway ARP flow is not created, because virtual router IP has not been set for subnet {} .",
+                            sn.getIpPrefix().getValue());
+                }
             }
         }
+
         // Write broadcast flows per flood domain.
-        for (Integer fdId : fdIds) {
-            if (groupExists(nodeId, fdId)) {
-                flowMap.writeFlow(nodeId, TABLE_ID, createBroadcastFlow(fdId));
+        for (EndpointFwdCtxOrdinals epOrd : epOrdSet) {
+            if (groupExists(nodeId, epOrd.getFdId())) {
+                flowMap.writeFlow(nodeId, TABLE_ID, createBroadcastFlow(epOrd));
             }
         }
     }
+
     // set up next-hop destinations for all the endpoints in the endpoint
     // group on the node
 
-
-    private Flow createBroadcastFlow(int fdId) {
-        FlowId flowId = new FlowId(new StringBuilder()
-                .append("broadcast|")
-                .append(fdId).toString());
+    private Flow createBroadcastFlow(EndpointFwdCtxOrdinals epOrd) {
+        FlowId flowId = new FlowId(new StringBuilder().
+                                    append("broadcast|").
+                                    append(epOrd.getFdId()).
+                                    toString());
         MatchBuilder mb = new MatchBuilder()
-                .setEthernetMatch(new EthernetMatchBuilder()
-                        .setEthernetDestination(new EthernetDestinationBuilder()
-                                .setAddress(MULTICAST_MAC)
-                                .setMask(MULTICAST_MAC)
-                                .build())
-                        .build());
-        addNxRegMatch(mb, RegMatch.of(NxmNxReg5.class, Long.valueOf(fdId)));
+                            .setEthernetMatch(new EthernetMatchBuilder()
+                            .setEthernetDestination(new EthernetDestinationBuilder().
+                                                        setAddress(MULTICAST_MAC)
+                                                        .setMask(MULTICAST_MAC).build())
+                            .build());
+        addNxRegMatch(mb, RegMatch.of(NxmNxReg5.class, Long.valueOf(epOrd.getFdId())));
+
+        FlowBuilder flowb = base().setPriority(Integer.valueOf(140))
+            .setId(flowId)
+            .setMatch(mb.build())
+            .setInstructions(
+                    instructions(applyActionIns(nxLoadTunIdAction(BigInteger.valueOf(epOrd.getFdId()), false),
+                            groupAction(Long.valueOf(epOrd.getFdId())))));
 
-        FlowBuilder flowb = base()
-                .setPriority(Integer.valueOf(140))
-                .setId(flowId)
-                .setMatch(mb.build())
-                .setInstructions(instructions(applyActionIns(nxMoveRegTunIdAction(NxmNxReg0.class, false),
-                        groupAction(Long.valueOf(fdId)))));
         return flowb.build();
     }
 
-
-
     private boolean groupExists(NodeId nodeId, Integer fdId) throws Exception {
         // Fetch existing GroupTables
-        if(ctx.getDataBroker()==null) {
+        if (ctx.getDataBroker() == null) {
             return false;
         }
 
         ReadOnlyTransaction t = ctx.getDataBroker().newReadOnlyTransaction();
         InstanceIdentifier<Node> niid = createNodePath(nodeId);
-        Optional<Node> r =
-                t.read(LogicalDatastoreType.CONFIGURATION, niid).get();
+        Optional<Node> r = t.read(LogicalDatastoreType.CONFIGURATION, niid).get();
         if (!r.isPresent())
             return false;
         FlowCapableNode fcn = r.get().getAugmentation(FlowCapableNode.class);
@@ -219,71 +264,111 @@ public class DestinationMapper extends FlowTable {
         return false;
     }
 
+    private MacAddress routerPortMac(L3Context l3c, IpAddress ipAddress) {
+
+        if (ctx.getDataBroker() == null) {
+            return null;
+        }
+
+        MacAddress defaultMacAddress = ROUTER_MAC;
+
+        EndpointL3Key l3Key = new EndpointL3Key(ipAddress, l3c.getId());
+        InstanceIdentifier<EndpointL3> endpointsIid = InstanceIdentifier.builder(Endpoints.class)
+            .child(EndpointL3.class, l3Key)
+            .build();
+        ReadOnlyTransaction t = ctx.getDataBroker().newReadOnlyTransaction();
 
-    private Flow createRouterArpFlow(NodeId nodeId,
-            Subnet sn,
-            int l3Id) {
-        if (sn != null && sn.getVirtualRouterIp() != null) {
-            if (sn.getVirtualRouterIp().getIpv4Address() != null) {
-                String ikey = sn.getVirtualRouterIp().getIpv4Address().getValue();
-                FlowId flowId = new FlowId(new StringBuffer()
-                        .append("routerarp|")
-                        .append(sn.getId().getValue())
-                        .append("|")
-                        .append(ikey)
-                        .append("|")
-                        .append(l3Id)
-                        .toString());
-                    MatchBuilder mb = new MatchBuilder()
-                            .setEthernetMatch(ethernetMatch(null, null, ARP))
-                            .setLayer3Match(new ArpMatchBuilder()
-                                    .setArpOp(Integer.valueOf(1))
-                                    .setArpTargetTransportAddress(new Ipv4Prefix(ikey + "/32"))
-                                    .build());
-                    addNxRegMatch(mb, RegMatch.of(NxmNxReg6.class,
-                            Long.valueOf(l3Id)));
-                    BigInteger routerMac =
-                            new BigInteger(1, bytesFromHexString(ROUTER_MAC
-                                    .getValue()));
-                    FlowBuilder flowb = base()
-                            .setPriority(150)
-                            .setId(flowId)
-                            .setMatch(mb.build())
-                            .setInstructions(instructions(applyActionIns(nxMoveEthSrcToEthDstAction(),
-                                    setDlSrcAction(ROUTER_MAC),
-                                    nxLoadArpOpAction(BigInteger.valueOf(2L)),
-                                    nxMoveArpShaToArpThaAction(),
-                                    nxLoadArpShaAction(routerMac),
-                                    nxMoveArpSpaToArpTpaAction(),
-                                    nxLoadArpSpaAction(ikey),
-                                    outputAction(new NodeConnectorId(nodeId.getValue() + ":INPORT")))));
-                    return flowb.build();
+        Optional<EndpointL3> r;
+        try {
+            r = t.read(LogicalDatastoreType.OPERATIONAL, endpointsIid).get();
+            if (!r.isPresent())
+                return defaultMacAddress;
+            EndpointL3 epL3 = r.get();
+            if (epL3.getMacAddress() == null) {
+                return defaultMacAddress;
             } else {
-                LOG.warn("IPv6 virtual router {} for subnet {} not supported",
-                        sn.getVirtualRouterIp(), sn.getId().getValue());
+                return epL3.getMacAddress();
             }
+        } catch (Exception e) {
+            LOG.error("Error reading EndpointL3 {}.{}", l3c, ipAddress, e);
+            return null;
         }
-        return null;
     }
 
+    private L3Context getL3ContextForSubnet(TenantId tenantId, Subnet sn) {
+        L3Context l3c = ctx.getPolicyResolver().getTenant(tenantId).resolveL3Context(sn.getId());
+        return l3c;
+    }
+
+    private Flow createRouterArpFlow(TenantId tenantId, NodeId nodeId, Subnet sn, int l3Id) {
+        if (sn == null || sn.getVirtualRouterIp() == null) {
+            LOG.trace("Didn't create routerArpFlow since either subnet or subnet virtual router was null");
+            return null;
+        }
+        /*
+         * TODO: Li alagalah: This should be new Yang "gateways" list as well,
+         * that expresses the gateway and prefixes it is interface for. Should
+         * also check for external.
+         */
+        if (sn.getVirtualRouterIp().getIpv4Address() != null) {
+            String ikey = sn.getVirtualRouterIp().getIpv4Address().getValue();
+
+            L3Context l3c = getL3ContextForSubnet(tenantId, sn);
+            if (l3c == null) {
+                LOG.error("No L3 Context found associated with subnet {}", sn.getId());
+            }
+
+            MacAddress routerMac = routerPortMac(l3c, sn.getVirtualRouterIp());
+            if (routerMac == null) {
+                return null;
+            }
+
+            BigInteger intRouterMac = new BigInteger(1, bytesFromHexString(routerMac.getValue()));
+
+            FlowId flowId = new FlowId(new StringBuffer().append("routerarp|")
+                .append(sn.getId().getValue())
+                .append("|")
+                .append(ikey)
+                .append("|")
+                .append(l3Id)
+                .toString());
+            MatchBuilder mb = new MatchBuilder().setEthernetMatch(ethernetMatch(null, null, ARP)).setLayer3Match(
+                    new ArpMatchBuilder().setArpOp(Integer.valueOf(1))
+                        .setArpTargetTransportAddress(new Ipv4Prefix(ikey + "/32"))
+                        .build());
+            addNxRegMatch(mb, RegMatch.of(NxmNxReg6.class, Long.valueOf(l3Id)));
+
+            FlowBuilder flowb = base().setPriority(150)
+                .setId(flowId)
+                .setMatch(mb.build())
+                .setInstructions(
+                        instructions(applyActionIns(nxMoveEthSrcToEthDstAction(), setDlSrcAction(routerMac),
+                                nxLoadArpOpAction(BigInteger.valueOf(2L)), nxMoveArpShaToArpThaAction(),
+                                nxLoadArpShaAction(intRouterMac), nxMoveArpSpaToArpTpaAction(),
+                                nxLoadArpSpaAction(ikey), outputAction(new NodeConnectorId(nodeId.getValue()
+                                        + ":INPORT")))));
+            return flowb.build();
+        } else {
+            LOG.warn("IPv6 virtual router {} for subnet {} not supported", sn.getVirtualRouterIp(), sn.getId()
+                .getValue());
+            return null;
+        }
+
+    }
 
     private Flow createLocalL2Flow(Endpoint ep, EndpointFwdCtxOrdinals epFwdCtxOrds, OfOverlayContext ofc) {
 
-        //TODO Li alagalah - refactor common code but keep simple method
+        // TODO Li alagalah - refactor common code but keep simple method
         ArrayList<Instruction> instructions = new ArrayList<>();
         List<Action> applyActions = new ArrayList<>();
 
         int order = 0;
 
-        Action setdEPG = nxLoadRegAction(NxmNxReg2.class,
-                BigInteger.valueOf(epFwdCtxOrds.getEpgId()));
-        Action setdCG = nxLoadRegAction(NxmNxReg3.class,
-                BigInteger.valueOf(epFwdCtxOrds.getCgId()));
+        Action setdEPG = nxLoadRegAction(NxmNxReg2.class, BigInteger.valueOf(epFwdCtxOrds.getEpgId()));
+        Action setdCG = nxLoadRegAction(NxmNxReg3.class, BigInteger.valueOf(epFwdCtxOrds.getCgId()));
         Action setNextHop;
         String nextHop;
 
-
-
         // BEGIN L2 LOCAL
         nextHop = ofc.getNodeConnectorId().getValue();
 
@@ -291,80 +376,61 @@ public class DestinationMapper extends FlowTable {
         try {
             portNum = getOfPortNum(ofc.getNodeConnectorId());
         } catch (NumberFormatException ex) {
-            LOG.warn("Could not parse port number {}",
-                    ofc.getNodeConnectorId(), ex);
+            LOG.warn("Could not parse port number {}", ofc.getNodeConnectorId(), ex);
             return null;
         }
 
-        setNextHop = nxLoadRegAction(NxmNxReg7.class,
-                BigInteger.valueOf(portNum));
+        setNextHop = nxLoadRegAction(NxmNxReg7.class, BigInteger.valueOf(portNum));
 
-        //END L2 LOCAL
+        // END L2 LOCAL
 
         order += 1;
         applyActions.add(setdEPG);
         applyActions.add(setdCG);
         applyActions.add(setNextHop);
-        Instruction applyActionsIns = new InstructionBuilder()
-                .setOrder(order++)
-                .setInstruction(applyActionIns(applyActions.toArray(new Action[applyActions.size()])))
-                .build();
+        Instruction applyActionsIns = new InstructionBuilder().setOrder(order++)
+            .setInstruction(applyActionIns(applyActions.toArray(new Action[applyActions.size()])))
+            .build();
         instructions.add(applyActionsIns);
 
-        Instruction gotoTable = new InstructionBuilder()
-                .setOrder(order++)
-                .setInstruction(gotoTableIns((short) (getTableId() + 1)))
-                .build();
+        Instruction gotoTable = new InstructionBuilder().setOrder(order++)
+            .setInstruction(gotoTableIns((short) (getTableId() + 1)))
+            .build();
         instructions.add(gotoTable);
 
-
-        FlowId flowid = new FlowId(new StringBuilder()
-                .append(epFwdCtxOrds.getBdId())
-                .append("|l2|")
-                .append(ep.getMacAddress().getValue())
-                .append("|")
-                .append(nextHop)
-                .toString());
-        MatchBuilder mb = new MatchBuilder()
-                .setEthernetMatch(ethernetMatch(null,
-                        ep.getMacAddress(),
-                        null));
+        FlowId flowid = new FlowId(new StringBuilder().append(epFwdCtxOrds.getBdId())
+            .append("|l2|")
+            .append(ep.getMacAddress().getValue())
+            .append("|")
+            .append(nextHop)
+            .toString());
+        MatchBuilder mb = new MatchBuilder().setEthernetMatch(ethernetMatch(null, ep.getMacAddress(), null));
         addNxRegMatch(mb, RegMatch.of(NxmNxReg4.class, Long.valueOf(epFwdCtxOrds.getBdId())));
-        FlowBuilder flowb = base()
-                .setId(flowid)
-                .setPriority(Integer.valueOf(50))
-                .setMatch(mb.build())
-                .setInstructions(new InstructionsBuilder()
-                        .setInstruction(instructions)
-                        .build());
+        FlowBuilder flowb = base().setId(flowid)
+            .setPriority(Integer.valueOf(50))
+            .setMatch(mb.build())
+            .setInstructions(new InstructionsBuilder().setInstruction(instructions).build());
         return flowb.build();
     }
 
-
-    private void syncEP(FlowMap flowMap,
-            NodeId nodeId, PolicyInfo policyInfo,
-            Endpoint epPeer, Set<EpKey> visitedEps)
+    private void syncEP(FlowMap flowMap, NodeId nodeId, PolicyInfo policyInfo, Endpoint srcEp, Endpoint destEp)
             throws Exception {
 
-        EpKey epPeerKey = new EpKey(epPeer.getL2Context(),epPeer.getMacAddress());
+        // TODO: Conditions messed up, but for now, send policyInfo until this
+        // is fixed.
+        EndpointFwdCtxOrdinals destEpFwdCtxOrds = OrdinalFactory.getEndpointFwdCtxOrdinals(ctx, policyInfo, destEp);
+        EndpointFwdCtxOrdinals srcEpFwdCtxOrds = OrdinalFactory.getEndpointFwdCtxOrdinals(ctx, policyInfo, srcEp);
 
-        if (visitedEps.contains(epPeerKey)) {
+        if (destEp.getTenant() == null || (destEp.getEndpointGroup() == null && destEp.getEndpointGroups() == null)) {
+            LOG.trace("Didn't process endpoint due to either tenant, or EPG(s) being null", destEp.getKey());
             return;
         }
-        visitedEps.add(epPeerKey);
-
-        // TODO: Conditions messed up, but for now, send policyInfo until this is fixed.
-        EndpointFwdCtxOrdinals epFwdCtxOrds = OrdinalFactory.getEndpointFwdCtxOrdinals(ctx, policyInfo, epPeer);
-
-        if (epPeer.getTenant() == null || (epPeer.getEndpointGroup() == null && epPeer.getEndpointGroups() == null))
-            return;
-        OfOverlayContext ofc = epPeer.getAugmentation(OfOverlayContext.class);
-
+        OfOverlayContext ofc = destEp.getAugmentation(OfOverlayContext.class);
 
-
-        //////////////////////////////////////////////////////////////////////////////////////////
+        // ////////////////////////////////////////////////////////////////////////////////////////
         /*
-         * NOT HANDLING EXTERNALS
+         * NOT HANDLING EXTERNALS TODO: alagalah Li: External Gateway
+         * functionality needed here.
          */
         if (LocationType.External.equals(ofc.getLocationType())) {
             // XXX - TODO - perform NAT and send to the external network
@@ -373,53 +439,155 @@ public class DestinationMapper extends FlowTable {
             return;
         }
 
+        /*
+         * Only care about subnets for L3, but fetch them before loop. We need
+         * the local subnets for setting SRC MAC for routing. All Routing is now
+         * done locally! YAY! Instead of being shovelled L2 style across network
+         * ala Helium.
+         */
+        List<Subnet> localSubnets = getLocalSubnets(nodeId);
+        if (localSubnets == null) {
+            LOG.error("No subnets could be found locally for node: {}", nodeId);
+            return;
+        }
+
         if (Objects.equals(ofc.getNodeId(), nodeId)) {
             // this is a local endpoint; send to the approppriate local
             // port
 
-            flowMap.writeFlow(nodeId, TABLE_ID, createLocalL2Flow(epPeer,epFwdCtxOrds,ofc));
-
-            if (epPeer.getL3Address() == null)
+            if (srcEpFwdCtxOrds.getBdId() == destEpFwdCtxOrds.getBdId()) {
+                flowMap.writeFlow(nodeId, TABLE_ID, createLocalL2Flow(destEp, destEpFwdCtxOrds, ofc));
+            }
+            // TODO Li alagalah: Need to move to EndpointL3 for L3 processing.
+            // The Endpoint conflation must end!
+            if (destEp.getL3Address() == null) {
+                LOG.trace("Endpoint {} didn't have L3 Address so was not processed for L3 flows.", destEp.getKey());
                 return;
-            for (L3Address l3a : epPeer.getL3Address()) {
+            }
+
+            for (L3Address l3a : destEp.getL3Address()) {
                 if (l3a.getIpAddress() == null || l3a.getL3Context() == null) {
-                    LOG.error("Endpoint with L3Address but either IPAddress or L3Context is null. {}",epPeer.getL3Address().toString());
+                    LOG.error("Endpoint with L3Address but either IPAddress or L3Context is null. {}",
+                            destEp.getL3Address());
                     continue;
                 } else {
-                    flowMap.writeFlow(nodeId, TABLE_ID, createLocalL3Flow(epPeer,l3a, epFwdCtxOrds,ofc));
+                    for (Subnet localSubnet : localSubnets) {
+                        Flow flow = createLocalL3RoutedFlow(destEp, l3a, destEpFwdCtxOrds, ofc, localSubnet);
+                        if (flow != null) {
+                            flowMap.writeFlow(nodeId, TABLE_ID, flow);
+                        } else {
+                            LOG.trace("Did not write remote L3 flow for endpoint {} and subnet {}", l3a.getIpAddress(),
+                                    localSubnet.getIpPrefix().getValue());
+                        }
+                    }
                 }
             }
         } else {
             // this endpoint is on a different switch; send to the
             // appropriate tunnel
+            if (srcEpFwdCtxOrds.getBdId() == destEpFwdCtxOrds.getBdId()) {
+                Flow remoteL2Flow = createRemoteL2Flow(destEp, nodeId, srcEpFwdCtxOrds, destEpFwdCtxOrds, ofc);
+                if (remoteL2Flow != null) {
+                    flowMap.writeFlow(nodeId, TABLE_ID, remoteL2Flow);
+                }
+            } else {
+                LOG.trace("DestinationMapper: RemoteL2Flow: not created, in different BDs src: {} dst: {}",
+                        srcEpFwdCtxOrds.getBdId(), destEpFwdCtxOrds.getBdId());
+            }
 
-             flowMap.writeFlow(nodeId, TABLE_ID, createRemoteL2Flow(epPeer, nodeId, epFwdCtxOrds, ofc));
-
-            if (epPeer.getL3Address() == null)
+            // TODO Li alagalah: Need to move to EndpointL3 for L3 processing.
+            // The Endpoint conflation must end!
+            if (destEp.getL3Address() == null) {
+                LOG.trace("Endpoint {} didn't have L3 Address so was not processed for L3 flows.", destEp.getKey());
                 return;
-            for (L3Address l3a : epPeer.getL3Address()) {
+            }
+            for (L3Address l3a : destEp.getL3Address()) {
                 if (l3a.getIpAddress() == null || l3a.getL3Context() == null) {
-                    LOG.error("Endpoint with L3Address but either IPAddress or L3Context is null. {}",epPeer.getL3Address().toString());
+                    LOG.error("Endpoint with L3Address but either IPAddress or L3Context is null. {}",
+                            destEp.getL3Address());
                     continue;
                 } else {
-                    flowMap.writeFlow(nodeId, TABLE_ID, createRemoteL3Flow(l3a, nodeId,epFwdCtxOrds, ofc));
+                    for (Subnet localSubnet : localSubnets) {
+                        Flow remoteL3Flow = createRemoteL3RoutedFlow(destEp, l3a, nodeId, srcEpFwdCtxOrds,
+                                destEpFwdCtxOrds, ofc, localSubnet);
+                        if (remoteL3Flow != null) {
+                            flowMap.writeFlow(nodeId, TABLE_ID, remoteL3Flow);
+                        } else {
+                            LOG.trace("Did not write remote L3 flow for endpoint {} and subnet {}", l3a.getIpAddress(),
+                                    localSubnet.getIpPrefix().getValue());
+                        }
+                    }
                 }
             }
         } // remote (tunnel)
 
-
-
         // }
 
     }
 
-    /* ##################################
-     * DestMapper Flow methods
+    /*
+     * ################################## DestMapper Flow methods
      * ##################################
      */
-    private Flow createLocalL3Flow(Endpoint ep,L3Address l3a, EndpointFwdCtxOrdinals epFwdCtxOrds,OfOverlayContext ofc) {
+    private Flow createLocalL3RoutedFlow(Endpoint destEp, L3Address destL3Address, EndpointFwdCtxOrdinals epFwdCtxOrds,
+            OfOverlayContext ofc, Subnet srcSubnet) {
+
+        // TODO Li alagalah - refactor common code but keep simple method
+
+        Subnet destSubnet = null;
+        HashSet<Subnet> subnets = getSubnets(destEp.getTenant());
+        if (subnets == null) {
+            LOG.trace("No subnets in tenant {}", destL3Address.getIpAddress());
+            return null;
+        }
+        NetworkDomainId epNetworkContainment = getEPNetworkContainment(destEp);
+        for (Subnet subnet : subnets) {
+            // TODO Li alagalah add IPv6 support
+            if (subnet.getId().getValue().equals(epNetworkContainment.getValue())) {
+                destSubnet = subnet;
+                break;
+            }
+        }
+        if (destSubnet == null) {
+            LOG.trace("Destination IP address does not match any subnet in tenant {}", destL3Address.getIpAddress());
+            return null;
+        }
+
+        if (destSubnet.getVirtualRouterIp() == null) {
+            LOG.trace("Destination subnet {} for Endpoint {}.{} has no gateway IP", destSubnet.getIpPrefix(),
+                    destL3Address.getKey());
+            return null;
+        }
+
+        if (srcSubnet.getVirtualRouterIp() == null) {
+            LOG.trace("Local subnet {} has no gateway IP", srcSubnet.getIpPrefix());
+            return null;
+        }
+        L3Context destL3c = getL3ContextForSubnet(destEp.getTenant(), destSubnet);
+        if (destL3c == null || destL3c.getId() == null) {
+            LOG.error("No L3 Context found associated with subnet {}", destSubnet.getId());
+            return null;
+        }
+        L3Context srcL3c = getL3ContextForSubnet(destEp.getTenant(), srcSubnet);
+        if (srcL3c == null || srcL3c.getId() == null) {
+            LOG.error("No L3 Context found associated with subnet {}", srcSubnet.getId());
+            return null;
+        }
+
+        if (!(srcL3c.getId().getValue().equals(destL3c.getId().getValue()))) {
+            LOG.trace("Trying to route between two L3Contexts {} and {}. Not currently supported.", srcL3c.getId()
+                .getValue(), destL3c.getId().getValue());
+            return null;
+        }
+
+        MacAddress matcherMac = routerPortMac(destL3c, srcSubnet.getVirtualRouterIp());
+        MacAddress epDestMac = destEp.getMacAddress();
+        MacAddress destSubnetGatewayMac = routerPortMac(destL3c, destSubnet.getVirtualRouterIp());
 
-        //TODO Li alagalah - refactor common code but keep simple method
+        if (srcSubnet.getId().getValue().equals(destSubnet.getId().getValue())) {
+            // This is our final destination, so match on actual EP mac.
+            matcherMac = epDestMac;
+        }
 
         ArrayList<Instruction> l3instructions = new ArrayList<>();
         List<Action> applyActions = new ArrayList<>();
@@ -427,16 +595,11 @@ public class DestinationMapper extends FlowTable {
 
         int order = 0;
 
-        Action setdEPG = nxLoadRegAction(NxmNxReg2.class,
-                BigInteger.valueOf(epFwdCtxOrds.getEpgId()));
-        Action setdCG = nxLoadRegAction(NxmNxReg3.class,
-                BigInteger.valueOf(epFwdCtxOrds.getCgId()));
+        Action setdEPG = nxLoadRegAction(NxmNxReg2.class, BigInteger.valueOf(epFwdCtxOrds.getEpgId()));
+        Action setdCG = nxLoadRegAction(NxmNxReg3.class, BigInteger.valueOf(epFwdCtxOrds.getCgId()));
         Action setNextHop;
         String nextHop;
 
-        Action setDlSrc = setDlSrcAction(ROUTER_MAC);
-        Action decTtl = decNwTtlAction();
-
         // BEGIN L3 LOCAL
         nextHop = ofc.getNodeConnectorId().getValue();
 
@@ -444,88 +607,84 @@ public class DestinationMapper extends FlowTable {
         try {
             portNum = getOfPortNum(ofc.getNodeConnectorId());
         } catch (NumberFormatException ex) {
-            LOG.warn("Could not parse port number {}",
-                    ofc.getNodeConnectorId(), ex);
+            LOG.warn("Could not parse port number {}", ofc.getNodeConnectorId(), ex);
             return null;
         }
 
-        setNextHop = nxLoadRegAction(NxmNxReg7.class,
-                BigInteger.valueOf(portNum));
+        setNextHop = nxLoadRegAction(NxmNxReg7.class, BigInteger.valueOf(portNum));
+        // END L3 LOCAL
+
+        // Lets not re-write the srcMac if its local.
+        if (!(matcherMac.getValue().equals(epDestMac.getValue()))) {
+            Action setDlSrc = setDlSrcAction(destSubnetGatewayMac);
+            l3ApplyActions.add(setDlSrc);
+        }
 
-        Action setDlDst = setDlDstAction(ep.getMacAddress());
+        Action setDlDst = setDlDstAction(epDestMac);
         l3ApplyActions.add(setDlDst);
-        //END L3 LOCAL
 
-        l3ApplyActions.add(setDlSrc);
+        Action decTtl = decNwTtlAction();
         l3ApplyActions.add(decTtl);
+
         order += 1;
         applyActions.add(setdEPG);
         applyActions.add(setdCG);
         applyActions.add(setNextHop);
 
         applyActions.addAll(l3ApplyActions);
-        Instruction applyActionsIns = new InstructionBuilder()
-                .setOrder(order++)
-                .setInstruction(applyActionIns(applyActions.toArray(new Action[applyActions.size()])))
-                .build();
+        Instruction applyActionsIns = new InstructionBuilder().setOrder(order++)
+            .setInstruction(applyActionIns(applyActions.toArray(new Action[applyActions.size()])))
+            .build();
 
         l3instructions.add(applyActionsIns);
-        Instruction gotoTable = new InstructionBuilder()
-        .setOrder(order++)
-        .setInstruction(gotoTableIns((short) (getTableId() + 1)))
-        .build();
+        Instruction gotoTable = new InstructionBuilder().setOrder(order++)
+            .setInstruction(gotoTableIns((short) (getTableId() + 1)))
+            .build();
         l3instructions.add(gotoTable);
         Layer3Match m = null;
         Long etherType = null;
         String ikey = null;
-        if (l3a.getIpAddress().getIpv4Address() != null) {
-            ikey = l3a.getIpAddress().getIpv4Address().getValue() + "/32";
+        if (destL3Address.getIpAddress().getIpv4Address() != null) {
+            ikey = destL3Address.getIpAddress().getIpv4Address().getValue() + "/32";
             etherType = IPv4;
-            m = new Ipv4MatchBuilder()
-                    .setIpv4Destination(new Ipv4Prefix(ikey))
-                    .build();
-        } else if (l3a.getIpAddress().getIpv6Address() != null) {
-            ikey = l3a.getIpAddress().getIpv6Address().getValue() + "/128";
+            m = new Ipv4MatchBuilder().setIpv4Destination(new Ipv4Prefix(ikey)).build();
+        } else if (destL3Address.getIpAddress().getIpv6Address() != null) {
+            ikey = destL3Address.getIpAddress().getIpv6Address().getValue() + "/128";
             etherType = IPv6;
-            m = new Ipv6MatchBuilder()
-                    .setIpv6Destination(new Ipv6Prefix(ikey))
-                    .build();
+            m = new Ipv6MatchBuilder().setIpv6Destination(new Ipv6Prefix(ikey)).build();
         } else {
-            LOG.error("Endpoint has IPAddress that is not recognised as either IPv4 or IPv6.",l3a.toString());
+            LOG.error("Endpoint has IPAddress that is not recognised as either IPv4 or IPv6.", destL3Address.toString());
             return null;
         }
 
-        FlowId flowid = new FlowId(new StringBuilder()
-                .append(Integer.toString(epFwdCtxOrds.getL3Id()))
-                .append("|l3|")
-                .append(ikey)
-                .append("|")
-                .append(Integer.toString(epFwdCtxOrds.getEpgId()))
-                .append(" ")
-                .append(Integer.toString(epFwdCtxOrds.getCgId()))
-                .append("|")
-                .append(nextHop)
-                .toString());
-        MatchBuilder mb = new MatchBuilder()
-                .setEthernetMatch(ethernetMatch(null,
-                        ROUTER_MAC,
-                        etherType))
-                .setLayer3Match(m);
-        addNxRegMatch(mb, RegMatch.of(NxmNxReg6.class,
-                Long.valueOf(epFwdCtxOrds.getL3Id())));
-        FlowBuilder flowb = base()
-                .setId(flowid)
-                .setPriority(Integer.valueOf(132))
-                .setMatch(mb.build())
-                .setInstructions(new InstructionsBuilder()
-                        .setInstruction(l3instructions)
-                        .build());
+        FlowId flowid = new FlowId(new StringBuilder().append(Integer.toString(epFwdCtxOrds.getL3Id()))
+            .append("|l3|")
+            .append(ikey)
+            .append("|")
+            .append(Integer.toString(epFwdCtxOrds.getEpgId()))
+            .append("|")
+            .append(Integer.toString(epFwdCtxOrds.getCgId()))
+            .append("|")
+            .append(matcherMac)
+            .append("|")
+            .append(destSubnetGatewayMac)
+            .append("|")
+            .append(nextHop)
+            .toString());
+        MatchBuilder mb = new MatchBuilder().setEthernetMatch(ethernetMatch(null, matcherMac, etherType))
+            .setLayer3Match(m);
+        addNxRegMatch(mb, RegMatch.of(NxmNxReg6.class, Long.valueOf(epFwdCtxOrds.getL3Id())));
+        FlowBuilder flowb = base().setId(flowid)
+            .setPriority(Integer.valueOf(132))
+            .setMatch(mb.build())
+            .setInstructions(new InstructionsBuilder().setInstruction(l3instructions).build());
         return flowb.build();
     }
 
-    private Flow createRemoteL2Flow(Endpoint ep, NodeId nodeId, EndpointFwdCtxOrdinals epFwdCtxOrds, OfOverlayContext ofc) {
+    private Flow createRemoteL2Flow(Endpoint ep, NodeId nodeId, EndpointFwdCtxOrdinals srcEpFwdCtxOrds,
+            EndpointFwdCtxOrdinals destEpFwdCtxOrds, OfOverlayContext ofc) {
 
-        //TODO Li alagalah - refactor common code but keep simple method
+        // TODO Li alagalah - refactor common code but keep simple method
 
         // this endpoint is on a different switch; send to the
         // appropriate tunnel
@@ -533,25 +692,24 @@ public class DestinationMapper extends FlowTable {
         ArrayList<Instruction> instructions = new ArrayList<>();
         List<Action> applyActions = new ArrayList<>();
 
-
         int order = 0;
 
-        Action setdEPG = nxLoadRegAction(NxmNxReg2.class,
-                BigInteger.valueOf(epFwdCtxOrds.getEpgId()));
-        Action setdCG = nxLoadRegAction(NxmNxReg3.class,
-                BigInteger.valueOf(epFwdCtxOrds.getCgId()));
+        Action setdEPG = nxLoadRegAction(NxmNxReg2.class, BigInteger.valueOf(destEpFwdCtxOrds.getEpgId()));
+        Action setdCG = nxLoadRegAction(NxmNxReg3.class, BigInteger.valueOf(destEpFwdCtxOrds.getCgId()));
         Action setNextHop;
         String nextHop;
 
         // BEGIN TUNNEL HANDLING
-        IpAddress tunDst =
-                ctx.getSwitchManager().getTunnelIP(ofc.getNodeId());
-        NodeConnectorId tunPort =
-                ctx.getSwitchManager().getTunnelPort(nodeId);
-        if (tunDst == null)
+        IpAddress tunDst = ctx.getSwitchManager().getTunnelIP(ofc.getNodeId(), TunnelTypeVxlan.class);
+        NodeConnectorId tunPort = ctx.getSwitchManager().getTunnelPort(nodeId, TunnelTypeVxlan.class);
+        if (tunDst == null) {
+            LOG.warn("Failed to get Tunnel IP for NodeId {} with EP {}", nodeId, ep);
             return null;
-        if (tunPort == null)
+        }
+        if (tunPort == null) {
+            LOG.warn("Failed to get Tunnel Port for NodeId {} with EP {}", nodeId, ep);
             return null;
+        }
 
         Action tundstAction;
 
@@ -560,8 +718,7 @@ public class DestinationMapper extends FlowTable {
             tundstAction = nxLoadTunIPv4Action(nextHop, false);
         } else if (tunDst.getIpv6Address() != null) {
             // nextHop = tunDst.getIpv6Address().getValue();
-            LOG.error("IPv6 tunnel destination {} for {} not supported",
-                    tunDst.getIpv6Address().getValue(),
+            LOG.error("IPv6 tunnel destination {} for {} not supported", tunDst.getIpv6Address().getValue(),
                     ofc.getNodeId());
             return null;
         } else {
@@ -574,17 +731,11 @@ public class DestinationMapper extends FlowTable {
         try {
             portNum = getOfPortNum(tunPort);
         } catch (NumberFormatException ex) {
-            LOG.warn("Could not parse port number {}",
-                    ofc.getNodeConnectorId(), ex);
+            LOG.warn("Could not parse port number {}", ofc.getNodeConnectorId(), ex);
             return null;
         }
 
-        setNextHop = nxLoadRegAction(NxmNxReg7.class,
-                BigInteger.valueOf(portNum));
-        Action tunIdAction =
-                nxMoveRegTunIdAction(NxmNxReg0.class, false);
-
-        applyActions.add(tunIdAction);
+        setNextHop = nxLoadRegAction(NxmNxReg7.class, BigInteger.valueOf(portNum));
         applyActions.add(tundstAction);
         // END TUNNEL
 
@@ -592,81 +743,118 @@ public class DestinationMapper extends FlowTable {
         applyActions.add(setdEPG);
         applyActions.add(setdCG);
         applyActions.add(setNextHop);
-        Instruction applyActionsIns = new InstructionBuilder()
-                .setOrder(order++)
-                .setInstruction(applyActionIns(applyActions.toArray(new Action[applyActions.size()])))
-                .build();
+        Instruction applyActionsIns = new InstructionBuilder().setOrder(order++)
+            .setInstruction(applyActionIns(applyActions.toArray(new Action[applyActions.size()])))
+            .build();
         instructions.add(applyActionsIns);
 
-        applyActionsIns = new InstructionBuilder()
-                .setOrder(order++)
-                .setInstruction(applyActionIns(applyActions.toArray(new Action[applyActions.size()])))
-                .build();
+        applyActionsIns = new InstructionBuilder().setOrder(order++)
+            .setInstruction(applyActionIns(applyActions.toArray(new Action[applyActions.size()])))
+            .build();
 
-        Instruction gotoTable = new InstructionBuilder()
-                .setOrder(order++)
-                .setInstruction(gotoTableIns((short) (getTableId() + 1)))
-                .build();
+        Instruction gotoTable = new InstructionBuilder().setOrder(order++)
+            .setInstruction(gotoTableIns((short) (getTableId() + 1)))
+            .build();
         instructions.add(gotoTable);
 
-        FlowId flowid = new FlowId(new StringBuilder()
-                .append(epFwdCtxOrds.getBdId())
-                .append("|l2|")
-                .append(ep.getMacAddress().getValue())
-                .append("|")
-                .append(nextHop)
-                .toString());
-        MatchBuilder mb = new MatchBuilder()
-                .setEthernetMatch(ethernetMatch(null,
-                        ep.getMacAddress(),
-                        null));
-        addNxRegMatch(mb, RegMatch.of(NxmNxReg4.class, Long.valueOf(epFwdCtxOrds.getBdId())));
-        FlowBuilder flowb = base()
-                .setId(flowid)
-                .setPriority(Integer.valueOf(50))
-                .setMatch(mb.build())
-                .setInstructions(new InstructionsBuilder()
-                        .setInstruction(instructions)
-                        .build());
+        FlowId flowid = new FlowId(new StringBuilder().append(destEpFwdCtxOrds.getBdId())
+            .append("|l2|")
+            .append(ep.getMacAddress().getValue())
+            .append("|")
+            .append(srcEpFwdCtxOrds.getBdId())
+            .append("|")
+            .append(nextHop)
+            .toString());
+        MatchBuilder mb = new MatchBuilder().setEthernetMatch(ethernetMatch(null, ep.getMacAddress(), null));
+        addNxRegMatch(mb, RegMatch.of(NxmNxReg4.class, Long.valueOf(destEpFwdCtxOrds.getBdId())));
+        FlowBuilder flowb = base().setId(flowid)
+            .setPriority(Integer.valueOf(50))
+            .setMatch(mb.build())
+            .setInstructions(new InstructionsBuilder().setInstruction(instructions).build());
 
         return flowb.build();
     }
 
+    private Flow createRemoteL3RoutedFlow(Endpoint destEp, L3Address destL3Address, NodeId nodeId,
+            EndpointFwdCtxOrdinals srcEpFwdCtxOrds, EndpointFwdCtxOrdinals destEpFwdCtxOrds, OfOverlayContext ofc,
+            Subnet srcSubnet) {
 
-    private Flow createRemoteL3Flow(L3Address l3a, NodeId nodeId, EndpointFwdCtxOrdinals epFwdCtxOrds,OfOverlayContext ofc) {
-
-        //TODO Li alagalah - refactor common code but keep simple method
-
+        // TODO Li alagalah - refactor common code but keep simple method
 
         // this endpoint is on a different switch; send to the
         // appropriate tunnel
+        Subnet destSubnet = null;
+        HashSet<Subnet> subnets = getSubnets(destEp.getTenant());
+        if (subnets == null) {
+            LOG.trace("No subnets in tenant {}", destL3Address.getIpAddress());
+            return null;
+        }
+        NetworkDomainId epNetworkContainment = getEPNetworkContainment(destEp);
+        for (Subnet subnet : subnets) {
+            // TODO Li alagalah add IPv6 support
+            if (subnet.getId().getValue().equals(epNetworkContainment.getValue())) {
+                destSubnet = subnet;
+                break;
+            }
+        }
+        if (destSubnet == null) {
+            LOG.info("Destination IP address does not match any subnet in tenant {}", destL3Address.getIpAddress());
+            return null;
+        }
+
+        if (destSubnet.getVirtualRouterIp() == null) {
+            LOG.trace("Destination subnet {} for Endpoint {}.{} has no gateway IP", destSubnet.getIpPrefix(),
+                    destL3Address.getKey());
+            return null;
+        }
+
+        if (srcSubnet.getVirtualRouterIp() == null) {
+            LOG.trace("Local subnet {} has no gateway IP", srcSubnet.getIpPrefix());
+            return null;
+        }
+        L3Context destL3c = getL3ContextForSubnet(destEp.getTenant(), destSubnet);
+        if (destL3c == null || destL3c.getId() == null) {
+            LOG.error("No L3 Context found associated with subnet {}", destSubnet.getId());
+            return null;
+        }
+        L3Context srcL3c = getL3ContextForSubnet(destEp.getTenant(), srcSubnet);
+        if (srcL3c == null || srcL3c.getId() == null) {
+            LOG.error("No L3 Context found associated with subnet {}", srcSubnet.getId());
+            return null;
+        }
+
+        if (!(srcL3c.getId().getValue().equals(destL3c.getId().getValue()))) {
+            LOG.trace("Trying to route between two L3Contexts {} and {}. Not currently supported.", srcL3c.getId()
+                .getValue(), destL3c.getId().getValue());
+            return null;
+        }
+
+        MacAddress matcherMac = routerPortMac(destL3c, srcSubnet.getVirtualRouterIp());
+        MacAddress epDestMac = destEp.getMacAddress();
+        MacAddress destSubnetGatewayMac = routerPortMac(destL3c, destSubnet.getVirtualRouterIp());
 
         ArrayList<Instruction> l3instructions = new ArrayList<>();
         List<Action> applyActions = new ArrayList<>();
         List<Action> l3ApplyActions = new ArrayList<>();
 
-
         int order = 0;
 
-        Action setdEPG = nxLoadRegAction(NxmNxReg2.class,
-                BigInteger.valueOf(epFwdCtxOrds.getEpgId()));
-        Action setdCG = nxLoadRegAction(NxmNxReg3.class,
-                BigInteger.valueOf(epFwdCtxOrds.getCgId()));
+        Action setdEPG = nxLoadRegAction(NxmNxReg2.class, BigInteger.valueOf(destEpFwdCtxOrds.getEpgId()));
+        Action setdCG = nxLoadRegAction(NxmNxReg3.class, BigInteger.valueOf(destEpFwdCtxOrds.getCgId()));
         Action setNextHop;
         String nextHop;
 
-        Action setDlSrc = setDlSrcAction(ROUTER_MAC);
-        Action decTtl = decNwTtlAction();
-
         // BEGIN TUNNEL HANDLING
-        IpAddress tunDst =
-                ctx.getSwitchManager().getTunnelIP(ofc.getNodeId());
-        NodeConnectorId tunPort =
-                ctx.getSwitchManager().getTunnelPort(nodeId);
-        if (tunDst == null)
+        IpAddress tunDst = ctx.getSwitchManager().getTunnelIP(ofc.getNodeId(), TunnelTypeVxlan.class);
+        NodeConnectorId tunPort = ctx.getSwitchManager().getTunnelPort(nodeId, TunnelTypeVxlan.class);
+        if (tunDst == null) {
+            LOG.warn("Failed to get Tunnel IP for NodeId {} with L3Address {}", nodeId, destL3Address);
             return null;
-        if (tunPort == null)
+        }
+        if (tunPort == null) {
+            LOG.warn("Failed to get Tunnel port for NodeId {} with L3Address {}", nodeId, destL3Address);
             return null;
+        }
 
         Action tundstAction;
 
@@ -675,8 +863,7 @@ public class DestinationMapper extends FlowTable {
             tundstAction = nxLoadTunIPv4Action(nextHop, false);
         } else if (tunDst.getIpv6Address() != null) {
             // nextHop = tunDst.getIpv6Address().getValue();
-            LOG.error("IPv6 tunnel destination {} for {} not supported",
-                    tunDst.getIpv6Address().getValue(),
+            LOG.error("IPv6 tunnel destination {} for {} not supported", tunDst.getIpv6Address().getValue(),
                     ofc.getNodeId());
             return null;
         } else {
@@ -689,90 +876,165 @@ public class DestinationMapper extends FlowTable {
         try {
             portNum = getOfPortNum(tunPort);
         } catch (NumberFormatException ex) {
-            LOG.warn("Could not parse port number {}",
-                    ofc.getNodeConnectorId(), ex);
+            LOG.warn("Could not parse port number {}", ofc.getNodeConnectorId(), ex);
             return null;
         }
 
-        setNextHop = nxLoadRegAction(NxmNxReg7.class,
-                BigInteger.valueOf(portNum));
-        Action tunIdAction =
-                nxMoveRegTunIdAction(NxmNxReg0.class, false);
-
-        applyActions.add(tunIdAction);
+        setNextHop = nxLoadRegAction(NxmNxReg7.class, BigInteger.valueOf(portNum));
         applyActions.add(tundstAction);
         // END TUNNEL
 
-
-        l3ApplyActions.add(setDlSrc);
-        l3ApplyActions.add(decTtl);
         order += 1;
         applyActions.add(setdEPG);
         applyActions.add(setdCG);
         applyActions.add(setNextHop);
+
+        Action setDlSrc = setDlSrcAction(destSubnetGatewayMac);
         l3ApplyActions.add(setDlSrc);
+
+        Action setDlDst = setDlDstAction(epDestMac);
+        l3ApplyActions.add(setDlDst);
+
+        Action decTtl = decNwTtlAction();
         l3ApplyActions.add(decTtl);
 
         applyActions.addAll(l3ApplyActions);
-        Instruction applyActionsIns = new InstructionBuilder()
-                .setOrder(order++)
-                .setInstruction(applyActionIns(applyActions.toArray(new Action[applyActions.size()])))
-                .build();
+        Instruction applyActionsIns = new InstructionBuilder().setOrder(order++)
+            .setInstruction(applyActionIns(applyActions.toArray(new Action[applyActions.size()])))
+            .build();
 
         l3instructions.add(applyActionsIns);
-        Instruction gotoTable = new InstructionBuilder()
-        .setOrder(order++)
-        .setInstruction(gotoTableIns((short) (getTableId() + 1)))
-        .build();
+        Instruction gotoTable = new InstructionBuilder().setOrder(order++)
+            .setInstruction(gotoTableIns((short) (getTableId() + 1)))
+            .build();
         l3instructions.add(gotoTable);
         Layer3Match m = null;
         Long etherType = null;
         String ikey = null;
-        if (l3a.getIpAddress().getIpv4Address() != null) {
-            ikey = l3a.getIpAddress().getIpv4Address().getValue() + "/32";
+        if (destL3Address.getIpAddress().getIpv4Address() != null) {
+            ikey = destL3Address.getIpAddress().getIpv4Address().getValue() + "/32";
             etherType = IPv4;
-            m = new Ipv4MatchBuilder()
-                    .setIpv4Destination(new Ipv4Prefix(ikey))
-                    .build();
-        } else if (l3a.getIpAddress().getIpv6Address() != null) {
-            ikey = l3a.getIpAddress().getIpv6Address().getValue() + "/128";
+            m = new Ipv4MatchBuilder().setIpv4Destination(new Ipv4Prefix(ikey)).build();
+        } else if (destL3Address.getIpAddress().getIpv6Address() != null) {
+            ikey = destL3Address.getIpAddress().getIpv6Address().getValue() + "/128";
             etherType = IPv6;
-            m = new Ipv6MatchBuilder()
-                    .setIpv6Destination(new Ipv6Prefix(ikey))
-                    .build();
+            m = new Ipv6MatchBuilder().setIpv6Destination(new Ipv6Prefix(ikey)).build();
         } else {
-            LOG.error("Endpoint has IPAddress that is not recognised as either IPv4 or IPv6.",l3a.toString());
+            LOG.error("Endpoint has IPAddress that is not recognised as either IPv4 or IPv6.", destL3Address.toString());
             return null;
         }
 
-        FlowId flowid = new FlowId(new StringBuilder()
-                .append(Integer.toString(epFwdCtxOrds.getL3Id()))
-                .append("|l3|")
-                .append(ikey)
-                .append("|")
-                .append(Integer.toString(epFwdCtxOrds.getEpgId()))
-                .append(" ")
-                .append(Integer.toString(epFwdCtxOrds.getCgId()))
-                .append("|")
-                .append(nextHop)
-                .toString());
-        MatchBuilder mb = new MatchBuilder()
-                .setEthernetMatch(ethernetMatch(null,
-                        ROUTER_MAC,
-                        etherType))
-                .setLayer3Match(m);
-        addNxRegMatch(mb, RegMatch.of(NxmNxReg6.class,
-                Long.valueOf(epFwdCtxOrds.getL3Id())));
-        FlowBuilder flowb = base()
-                .setId(flowid)
-                .setPriority(Integer.valueOf(132))
-                .setMatch(mb.build())
-                .setInstructions(new InstructionsBuilder()
-                        .setInstruction(l3instructions)
-                        .build());
+        FlowId flowid = new FlowId(new StringBuilder().append(Integer.toString(destEpFwdCtxOrds.getL3Id()))
+            .append("|l3|")
+            .append(ikey)
+            .append("|")
+            .append(matcherMac)
+            .append("|")
+            .append(destSubnetGatewayMac)
+            .append("|")
+            .append(srcEpFwdCtxOrds.getL3Id())
+            .append("|")
+            .append(nextHop)
+            .toString());
+        MatchBuilder mb = new MatchBuilder().setEthernetMatch(ethernetMatch(null, matcherMac, etherType))
+            .setLayer3Match(m);
+        addNxRegMatch(mb, RegMatch.of(NxmNxReg6.class, Long.valueOf(destEpFwdCtxOrds.getL3Id())));
+
+        FlowBuilder flowb = base().setId(flowid)
+            .setPriority(Integer.valueOf(132))
+            .setMatch(mb.build())
+            .setInstructions(new InstructionsBuilder().setInstruction(l3instructions).build());
         return flowb.build();
     }
 
+    private NetworkDomainId getEPNetworkContainment(Endpoint endpoint) {
+        if (endpoint.getNetworkContainment() != null) {
+            return endpoint.getNetworkContainment();
+        } else {
+            /*
+             * TODO: Be alagalah: Endpoint Refactor: This should be set on input
+             * which we can't do because of the backwards way endpoints were
+             * "architected".
+             */
+            return ctx.getPolicyResolver()
+                .getTenant(endpoint.getTenant())
+                .getEndpointGroup(endpoint.getEndpointGroup())
+                .getNetworkDomain();
+        }
+    }
+
+    private HashSet<Subnet> getSubnets(final TenantId tenantId) {
+
+        // if (subnetsByTenant.get(tenantId) != null) {
+        // return subnetsByTenant.get(tenantId);
+        // }
+
+        if (ctx.getDataBroker() == null) {
+            return null;
+        }
+
+        ReadOnlyTransaction t = ctx.getDataBroker().newReadOnlyTransaction();
+        InstanceIdentifier<Tenant> tiid = TenantUtils.tenantIid(tenantId);
+        Optional<Tenant> tenantInfo;
+        try {
+            tenantInfo = t.read(LogicalDatastoreType.CONFIGURATION, tiid).get();
+        } catch (Exception e) {
+            LOG.error("Could not read Tenant {}", tenantId, e);
+            return null;
+        }
+
+        HashSet<Subnet> subnets = new HashSet<Subnet>();
+
+        if (!tenantInfo.isPresent()) {
+            LOG.warn("Tenant {} not found", tenantId);
+            return null;
+        }
+
+        subnets.addAll(tenantInfo.get().getSubnet());
+        // subnetsByTenant.put(tenantId, subnets);
+        return subnets;
+    }
+
+    // Need a method to get subnets for EPs attached to the node locally
+    // to set the source Mac address for the router interface.
+    private List<Subnet> getLocalSubnets(NodeId nodeId) {
+        Collection<Endpoint> endpointsForNode = ctx.getEndpointManager().getEndpointsForNode(nodeId);
+
+        List<Subnet> localSubnets = new ArrayList<Subnet>();
+
+        for (Endpoint endpoint : endpointsForNode) {
+            HashSet<Subnet> subnets = getSubnets(endpoint.getTenant());
+            if (subnets == null) {
+                LOG.error("No local subnets.");
+                return null;
+            }
+            NetworkDomainId epNetworkContainment = getEPNetworkContainment(endpoint);
+            for (Subnet subnet : subnets) {
+                if (epNetworkContainment.getValue().equals(subnet.getId().getValue())) {
+                    localSubnets.add(subnet);
+                }
+            }
+        }
+        return localSubnets;
+    }
+
+    /**
+     * Reads data from datastore as synchronous call.
+     *
+     * @return {@link Optional#isPresent()} is {@code true} if reading was
+     *         successful and data exists in datastore; {@link Optional#isPresent()} is
+     *         {@code false} otherwise
+     */
+    public static <T extends DataObject> Optional<T> readFromDs(LogicalDatastoreType store, InstanceIdentifier<T> path,
+            ReadTransaction rTx) {
+        CheckedFuture<Optional<T>, ReadFailedException> resultFuture = rTx.read(store, path);
+        try {
+            return resultFuture.checkedGet();
+        } catch (ReadFailedException e) {
+            LOG.warn("Read failed from DS.", e);
+            return Optional.absent();
+        }
+    }
 
     static byte[] bytesFromHexString(String values) {
         String target = "";