[Emu] [ONOS-2600] Implement Basic BGP Update protocol message parsing and decode…

… excluding path attributes.

Change-Id: I37ed38cb79583fbbb31057dafc06df245aef3c49

+/*
+ * 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.bgpio.protocol;
+
+import java.util.List;
+
+import org.onlab.packet.IpPrefix;
+import org.onosproject.bgpio.protocol.ver4.BgpPathAttributes;
+
+/**
+ * Abstraction of an entity providing BGP Update Message.
+ */
+public interface BgpUpdateMsg extends BGPMessage {
+    /**
+     * Returns path attributes in BGP Update Message.
+     *
+     * @return path attributes in BGP Update Message
+     */
+    BgpPathAttributes bgpPathAttributes();
+
+    /**
+     * Returns withdrawn Routes.
+     *
+     * @return withdrawn Routes
+     */
+    List<IpPrefix> withdrawnRoutes();
+
+    /**
+     * Returns NLRI list of prefix.
+     *
+     * @return NLRI list of prefix
+     */
+    List<IpPrefix> nlri();
+}