ONOS-2197 Adding the skeletal DHCP Server, Packet builder, processor, store

Change-Id: Ie650766e6290f4950445e5ac23f1982e3a8fec57
diff --git a/onos-app-dhcpserver/src/main/java/org/onosproject/dhcpserver/DHCPStore.java b/onos-app-dhcpserver/src/main/java/org/onosproject/dhcpserver/DHCPStore.java
new file mode 100644
index 0000000..0a3d973
--- /dev/null
+++ b/onos-app-dhcpserver/src/main/java/org/onosproject/dhcpserver/DHCPStore.java
@@ -0,0 +1,58 @@
+/*
+ * Copyright 2014 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.dhcpserver;
+
+import org.onlab.packet.Ip4Address;
+import org.onlab.packet.MacAddress;
+
+/**
+ * DHCPStore Interface.
+ */
+public interface DHCPStore {
+
+    /**
+     * Returns an IP Address for a Mac ID, in response to a DHCP DISCOVER message.
+     *
+     * @param macID Mac ID of the client requesting an IP
+     * @return IP address assigned to the Mac ID
+     */
+    Ip4Address suggestIP(MacAddress macID);
+
+    /**
+     * Assigns the requested IP to the Mac ID, in response to a DHCP REQUEST message.
+     *
+     * @param macID Mac Id of the client requesting an IP
+     * @param ipAddr IP Address being requested
+     * @param leaseTime Lease time offered by the server for this mapping
+     * @return returns true if the assignment was successful, false otherwise
+     */
+    boolean assignIP(MacAddress macID, Ip4Address ipAddr, long leaseTime);
+
+    /**
+     * Sets the default time for which suggested IP mappings are valid.
+     *
+     * @param timeInSeconds default time for IP mappings to be valid
+     */
+    void setDefaultTimeoutForPurge(long timeInSeconds);
+
+    /**
+     * Releases the IP assigned to a Mac ID into the free pool.
+     *
+     * @param macID the macID for which the mapping needs to be changed
+     */
+    void releaseIP(MacAddress macID);
+
+}