ONOS-688 (ONOS-1835,1836,1837) :
 - Implements features to create and remove tunnels and tunnel flow policies.
 - Implements REST API to create/show/delete tunnels and policies.
 - Supports only single instance for now.
 - Fix "apply" actions to "write" actions of all flow rules
Change-Id: I3740ed82fed8eab4ab8b03839192da72d3e223f1
diff --git a/src/main/java/org/onosproject/segmentrouting/DefaultTunnel.java b/src/main/java/org/onosproject/segmentrouting/DefaultTunnel.java
new file mode 100644
index 0000000..f1c0216
--- /dev/null
+++ b/src/main/java/org/onosproject/segmentrouting/DefaultTunnel.java
@@ -0,0 +1,168 @@
+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.onosproject.segmentrouting;
+
+import org.onosproject.net.DeviceId;
+import org.onosproject.net.Link;
+import org.onosproject.segmentrouting.grouphandler.NeighborSet;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+/**
+ * Tunnel class.
+ */
+public class DefaultTunnel implements Tunnel {
+
+    private static final Logger log = LoggerFactory
+            .getLogger(DefaultTunnel.class);
+
+    private final String tunnelId;
+    private final List<Integer> labelIds;
+    private final SegmentRoutingManager srManager;
+    private final DeviceConfiguration config;
+
+    private int groupId;
+
+    /**
+     * Creates a Tunnel reference.
+     *
+     * @param srm SegmentRoutingManager object
+     * @param tid  Tunnel ID
+     * @param labelIds Label stack of the tunnel
+     */
+    public DefaultTunnel(SegmentRoutingManager srm, String tid,
+                         List<Integer> labelIds) {
+        this.srManager = checkNotNull(srm);
+        this.tunnelId = checkNotNull(tid);
+        this.labelIds = Collections.unmodifiableList(labelIds);
+        this.config = srManager.deviceConfiguration;
+        this.groupId = -1;
+    }
+
+    /**
+     * Creates a Tunnel reference.
+     *
+     * @param tid  Tunnel ID
+     * @param labelIds Label stack of the tunnel
+     */
+    public DefaultTunnel(String tid, List<Integer> labelIds) {
+        this.srManager = null;
+        this.tunnelId = checkNotNull(tid);
+        this.labelIds = Collections.unmodifiableList(labelIds);
+        this.config = null;
+        this.groupId = -1;
+    }
+
+    /**
+     * Creates a new DefaultTunnel reference using the tunnel reference.
+     *
+     * @param tunnel DefaultTunnel reference
+     */
+    public DefaultTunnel(DefaultTunnel tunnel) {
+        this.srManager = tunnel.srManager;
+        this.tunnelId = tunnel.tunnelId;
+        this.labelIds = tunnel.labelIds;
+        this.config = tunnel.config;
+        this.groupId = tunnel.groupId;
+    }
+
+    @Override
+    public String id() {
+        return this.tunnelId;
+    }
+
+    @Override
+    public List<Integer> labelIds() {
+        return this.labelIds;
+    }
+
+    @Override
+    public boolean create() {
+
+        if (labelIds.isEmpty() || labelIds.size() < 3) {
+            log.error("More than one router needs to specified to created a tunnel");
+            return false;
+        }
+
+        groupId = createGroupsForTunnel();
+        if (groupId < 0) {
+            log.error("Failed to create groups for the tunnel");
+            return false;
+        }
+
+        return true;
+    }
+
+    @Override
+    public boolean remove() {
+
+        DeviceId deviceId = config.getDeviceId(labelIds.get(0));
+        srManager.removeNextObjective(deviceId, groupId);
+
+        return true;
+    }
+
+    @Override
+    public int groupId() {
+        return this.groupId;
+    }
+
+    @Override
+    public DeviceId source() {
+        return config.getDeviceId(labelIds.get(0));
+    }
+
+    private int createGroupsForTunnel() {
+
+        List<Integer> portNumbers;
+
+        int groupId;
+
+        DeviceId deviceId = config.getDeviceId(labelIds.get(0));
+        if (deviceId == null) {
+            log.warn("No device found for SID {}", labelIds.get(0));
+            return -1;
+        }
+        Set<DeviceId> deviceIds = new HashSet<>();
+        int sid = labelIds.get(1);
+        if (config.isAdjacencySid(deviceId, sid)) {
+            portNumbers = config.getPortsForAdjacencySid(deviceId, sid);
+            for (Link link: srManager.linkService.getDeviceEgressLinks(deviceId)) {
+                for (Integer port: portNumbers) {
+                    if (link.src().port().toLong() == port) {
+                        deviceIds.add(link.dst().deviceId());
+                    }
+                }
+            }
+        } else {
+            deviceIds.add(config.getDeviceId(sid));
+        }
+
+        NeighborSet ns = new NeighborSet(deviceIds, labelIds.get(2));
+        groupId = srManager.getNextObjectiveId(deviceId, ns);
+
+        return groupId;
+    }
+
+}