Packet throttle support

Change-Id: I6f2da5ed25f794561349013bfcbf9afa85d5e190
diff --git a/core/api/src/main/java/org/onosproject/net/packet/packetfilter/ArpPacketClassifier.java b/core/api/src/main/java/org/onosproject/net/packet/packetfilter/ArpPacketClassifier.java
new file mode 100644
index 0000000..5aed044
--- /dev/null
+++ b/core/api/src/main/java/org/onosproject/net/packet/packetfilter/ArpPacketClassifier.java
@@ -0,0 +1,37 @@
+/*
+ * Copyright 2019-present Open Networking Foundation
+ *
+ * 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.net.packet.packetfilter;
+
+import org.onlab.packet.ARP;
+import org.onlab.packet.Ethernet;
+import org.onosproject.net.packet.PacketContext;
+import org.onosproject.net.packet.PacketInClassifier;
+
+public class ArpPacketClassifier implements PacketInClassifier {
+
+    @Override
+    public boolean match(PacketContext packet) {
+
+        Ethernet eth = packet.inPacket().parsed();
+        if (eth != null && (eth.getEtherType() == Ethernet.TYPE_ARP)) {
+            ARP arpPacket = (ARP) eth.getPayload();
+            if (arpPacket.getOpCode() == ARP.OP_REQUEST) {
+                return true;
+            }
+        }
+        return false;
+    }
+}