diff --git a/py_gen/templates/_message_extra.py b/py_gen/templates/_message_extra.py
new file mode 100644
index 0000000..9fc2f5e
--- /dev/null
+++ b/py_gen/templates/_message_extra.py
@@ -0,0 +1,39 @@
+:: # Copyright 2013, Big Switch Networks, Inc.
+:: #
+:: # LoxiGen is licensed under the Eclipse Public License, version 1.0 (EPL), with
+:: # the following special exception:
+:: #
+:: # LOXI Exception
+:: #
+:: # As a special exception to the terms of the EPL, you may distribute libraries
+:: # generated by LoxiGen (LoxiGen Libraries) under the terms of your choice, provided
+:: # that copyright and licensing notices generated by LoxiGen are not altered or removed
+:: # from the LoxiGen Libraries and the notice provided below is (i) included in
+:: # the LoxiGen Libraries, if distributed in source code form and (ii) included in any
+:: # documentation for the LoxiGen Libraries, if distributed in binary form.
+:: #
+:: # Notice: "Copyright 2013, Big Switch Networks, Inc. This library was generated by the LoxiGen Compiler."
+:: #
+:: # You may not use this file except in compliance with the EPL or LOXI Exception. You may obtain
+:: # a copy of the EPL at:
+:: #
+:: # http://www.eclipse.org/legal/epl-v10.html
+:: #
+:: # 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
+:: # EPL for the specific language governing permissions and limitations
+:: # under the EPL.
+::
+def parse_header(buf):
+    if len(buf) < 8:
+        raise loxi.ProtocolError("too short to be an OpenFlow message")
+    return struct.unpack_from("!BBHL", buf)
+
+def parse_message(buf):
+    msg_ver, msg_type, msg_len, msg_xid = parse_header(buf)
+    if msg_ver != const.OFP_VERSION and msg_type != const.OFPT_HELLO:
+        raise loxi.ProtocolError("wrong OpenFlow version (expected %d, got %d)" % (const.OFP_VERSION, msg_ver))
+    if len(buf) != msg_len:
+        raise loxi.ProtocolError("incorrect message size")
+    return message.unpack(loxi.generic_util.OFReader(buf))