using subnet as lease/range selection criteria in DHCP Relay App, addressed review comments

Change-Id: Id2a81faa00592df4ede33f6679c2ba2dd8fb2293

 COMPILE_DEPS = [
     '//lib:CORE_DEPS',
+    '//incubator/api:onos-incubator-api',
 ]
 
 osgi_jar (

@@ -49,6 +49,11 @@
 
         <dependency>
             <groupId>org.onosproject</groupId>
+            <artifactId>onos-incubator-api</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>org.onosproject</groupId>
             <artifactId>onlab-osgi</artifactId>
             <version>${project.version}</version>
         </dependency>

@@ -20,18 +20,25 @@ import org.onosproject.net.ConnectPoint;
 import org.onosproject.net.config.Config;
 
 import static org.onosproject.net.config.Config.FieldPresence.MANDATORY;
+
+import org.onlab.packet.Ip4Address;
+import org.onlab.packet.MacAddress;
 /**
  * DHCP Relay Config class.
  */
 public class DhcpRelayConfig extends Config<ApplicationId> {
 
     private static final String DHCP_CONNECT_POINT = "dhcpserverConnectPoint";
+    private static final String DHCP_SERVER_IP = "serverip";
+    private static final String DHCP_SERVER_MAC = "servermac";
 
     @Override
     public boolean isValid() {
 
-        return hasOnlyFields(DHCP_CONNECT_POINT) &&
-                isConnectPoint(DHCP_CONNECT_POINT, MANDATORY);
+        return hasOnlyFields(DHCP_CONNECT_POINT, DHCP_SERVER_IP, DHCP_SERVER_MAC) &&
+                isConnectPoint(DHCP_CONNECT_POINT, MANDATORY) &&
+                isIpAddress(DHCP_SERVER_IP, MANDATORY) &&
+                isMacAddress(DHCP_SERVER_MAC, MANDATORY);
     }
 
     /**
@@ -42,4 +49,24 @@ public class DhcpRelayConfig extends Config<ApplicationId> {
     public ConnectPoint getDhcpServerConnectPoint() {
         return ConnectPoint.deviceConnectPoint(object.path(DHCP_CONNECT_POINT).asText());
     }
+
+    /**
+     * Returns the dhcp server ip.
+     *
+     * @return ip address or null if not set
+     */
+    public Ip4Address getDhcpServerIp() {
+        String ip = get(DHCP_SERVER_IP, null);
+        return ip != null ? Ip4Address.valueOf(ip) : null;
+    }
+
+    /**
+     * Returns the dhcp server mac.
+     *
+     * @return server mac or null if not set
+     */
+    public MacAddress getDhcpServermac() {
+        String mac = get(DHCP_SERVER_MAC, null);
+        return mac != null ? MacAddress.valueOf(mac) : null;
+    }
 }

@@ -2,7 +2,9 @@
   "apps": {
     "org.onosproject.dhcp-relay" : {
       "dhcprelay" : {
-        "dhcpserverConnectPoint": "of:0000000000000002/2"
+        "dhcpserverConnectPoint": "of:0000000000000002/2",
+        "serverip": "172.168.10.2",
+        "servermac": "d2:70:98:90:8c:44"
       }
     }
   }