add CLI for vBNG to show IP address mappings

Change-Id: I50035a69de43fcbe374bdceacfa2d2ba8f1af130
diff --git a/apps/virtualbng/src/main/java/org/onosproject/virtualbng/VbngConfigurationService.java b/apps/virtualbng/src/main/java/org/onosproject/virtualbng/VbngConfigurationService.java
index c905020..31e6d4f 100644
--- a/apps/virtualbng/src/main/java/org/onosproject/virtualbng/VbngConfigurationService.java
+++ b/apps/virtualbng/src/main/java/org/onosproject/virtualbng/VbngConfigurationService.java
@@ -15,6 +15,8 @@
  */
 package org.onosproject.virtualbng;
 
+import java.util.Map;
+
 import org.onlab.packet.IpAddress;
 import org.onlab.packet.MacAddress;
 
@@ -71,4 +73,12 @@
      * @return the assigned public IP address if it exists, otherwise null
      */
     IpAddress recycleAssignedPublicIpAddress(IpAddress privateIpAddress);
+
+    /**
+     * Gets all the mapping entries from private IP address to public IP
+     * address.
+     *
+     * @return the address map from private IP address to public IP address
+     */
+    Map<IpAddress, IpAddress> getIpAddressMappings();
 }