Kryo related changes.

Change-Id: I5b4fab63d6ece084b65aa712971a22d953d0caf0
diff --git a/core/store/src/main/java/org/onlab/onos/store/device/impl/IpPrefixSerializer.java b/core/store/src/main/java/org/onlab/onos/store/device/impl/IpPrefixSerializer.java
new file mode 100644
index 0000000..3d3efe0
--- /dev/null
+++ b/core/store/src/main/java/org/onlab/onos/store/device/impl/IpPrefixSerializer.java
@@ -0,0 +1,36 @@
+package org.onlab.onos.store.device.impl;
+
+import org.onlab.packet.IpPrefix;
+
+import com.esotericsoftware.kryo.Kryo;
+import com.esotericsoftware.kryo.Serializer;
+import com.esotericsoftware.kryo.io.Input;
+import com.esotericsoftware.kryo.io.Output;
+
+// TODO move to util, etc.
+public final class IpPrefixSerializer extends Serializer<IpPrefix> {
+
+    public IpPrefixSerializer() {
+        // non-null, immutable
+        super(false, true);
+    }
+
+    @Override
+    public void write(Kryo kryo, Output output,
+            IpPrefix object) {
+        byte[] octs = object.toOctets();
+        output.writeInt(octs.length);
+        output.writeBytes(octs);
+        output.writeInt(object.prefixLength());
+    }
+
+    @Override
+    public IpPrefix read(Kryo kryo, Input input,
+            Class<IpPrefix> type) {
+        int octLen = input.readInt();
+        byte[] octs = new byte[octLen];
+        input.read(octs);
+        int prefLen = input.readInt();
+        return IpPrefix.valueOf(octs, prefLen);
+    }
+}