:: # 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 != ofp.OFP_VERSION and msg_type != ofp.OFPT_HELLO:
        raise loxi.ProtocolError("wrong OpenFlow version (expected %d, got %d)" % (ofp.OFP_VERSION, msg_ver))
    if len(buf) != msg_len:
        raise loxi.ProtocolError("incorrect message size")
    return message.unpack(loxi.generic_util.OFReader(buf))