ofproto_v1_3_parser.py

# Copyright (C) 2012 Nippon Telegraph and Telephone Corporation.
# Copyright (C) 2012, 2013 Isaku Yamahata <yamahata at valinux co jp>
#
# 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.

"""
This module implements OpenFlow 1.3.x.

This module also implements some of extensions shown in
"OpenFlow Extensions for 1.3.X Pack 1".
Namely, the following extensions are implemented.

    - EXT-236 Bad flow entry priority error Extension
    - EXT-237 Set async config error Extension
    - EXT-256 PBB UCA header field Extension
    - EXT-260 Duplicate instruction error Extension
    - EXT-264 Multipart timeout errors Extension

The following extensions are partially implemented.

    - EXT-187 Flow entry notifications Extension (ONFMP_FLOW_MONITOR only)
    - EXT-230 Bundle Extension (Error codes only)
    - EXT-232 Table synchronisation Extension (Error codes only)

The following extensions are not implemented yet.

    - EXT-191 Role Status Extension
    - EXT-192-e Flow entry eviction Extension
    - EXT-192-v Vacancy events Extension
"""

import struct
import itertools

from ryu.lib import addrconv
from ryu.lib import mac
from ryu import utils
from ofproto_parser import StringifyMixin, MsgBase, msg_pack_into, msg_str_attr
from . import ether
from . import ofproto_parser
from . import ofproto_common
from . import ofproto_v1_3 as ofproto

import logging
LOG = logging.getLogger('ryu.ofproto.ofproto_v1_3_parser')

_MSG_PARSERS = {}


def _set_msg_type(msg_type):
    def _set_cls_msg_type(cls):
        cls.cls_msg_type = msg_type
        return cls
    return _set_cls_msg_type


def _register_parser(cls):
    '''class decorator to register msg parser'''
    assert cls.cls_msg_type is not None
    assert cls.cls_msg_type not in _MSG_PARSERS
    _MSG_PARSERS[cls.cls_msg_type] = cls.parser
    return cls


@ofproto_parser.register_msg_parser(ofproto.OFP_VERSION)
def msg_parser(datapath, version, msg_type, msg_len, xid, buf):
    parser = _MSG_PARSERS.get(msg_type)
    return parser(datapath, version, msg_type, msg_len, xid, buf)


@_register_parser
@_set_msg_type(ofproto.OFPT_HELLO)
class OFPHello(MsgBase):
    """
    Hello message

    When connection is started, the hello message is exchanged between a
    switch and a controller.

    This message is handled by the Ryu framework, so the Ryu application
    do not need to process this typically.

    ========== =========================================================
    Attribute  Description
    ========== =========================================================
    elements   list of ``OFPHelloElemVersionBitmap`` instance
    ========== =========================================================
    """
    def __init__(self, datapath, elements=[]):
        super(OFPHello, self).__init__(datapath)
        self.elements = elements

    @classmethod
    def parser(cls, datapath, version, msg_type, msg_len, xid, buf):
        msg = super(OFPHello, cls).parser(datapath, version, msg_type,
                                          msg_len, xid, buf)

        offset = ofproto.OFP_HELLO_HEADER_SIZE
        elems = []
        while offset < msg.msg_len:
            type_, length = struct.unpack_from(
                ofproto.OFP_HELLO_ELEM_HEADER_PACK_STR, msg.buf, offset)

            # better to register Hello Element classes but currently
            # Only VerisonBitmap is supported so let's be simple.

            if type_ == ofproto.OFPHET_VERSIONBITMAP:
                elem = OFPHelloElemVersionBitmap.parser(msg.buf, offset)
                elems.append(elem)

            offset += length
        msg.elements = elems
        return msg


class OFPHelloElemVersionBitmap(StringifyMixin):
    """
    Version bitmap Hello Element

    ========== =========================================================
    Attribute  Description
    ========== =========================================================
    versions   list of versions of OpenFlow protocol a device supports
    ========== =========================================================
    """
    def __init__(self, versions, type_=None, length=None):
        super(OFPHelloElemVersionBitmap, self).__init__()
        self.type = ofproto.OFPHET_VERSIONBITMAP
        self.length = None
        self._bitmaps = None
        self.versions = versions

    @classmethod
    def parser(cls, buf, offset):
        type_, length = struct.unpack_from(
            ofproto.OFP_HELLO_ELEM_VERSIONBITMAP_HEADER_PACK_STR,
            buf, offset)
        assert type_ == ofproto.OFPHET_VERSIONBITMAP

        bitmaps_len = (length -
                       ofproto.OFP_HELLO_ELEM_VERSIONBITMAP_HEADER_SIZE)
        offset += ofproto.OFP_HELLO_ELEM_VERSIONBITMAP_HEADER_SIZE
        bitmaps = []
        while bitmaps_len >= 4:
            bitmap = struct.unpack_from('!I', buf, offset)
            bitmaps.append(bitmap[0])
            offset += 4
            bitmaps_len -= 4

        versions = [i * 32 + shift
                    for i, bitmap in enumerate(bitmaps)
                    for shift in range(31) if bitmap & (1 << shift)]
        elem = cls(versions)
        elem.length = length
        elem._bitmaps = bitmaps
        return elem


@_register_parser
@_set_msg_type(ofproto.OFPT_ERROR)
class OFPErrorMsg(MsgBase):
    """
    Error message

    The switch notifies controller of problems by this message.

    ========== =========================================================
    Attribute  Description
    ========== =========================================================
    type       High level type of error
    code       Details depending on the type
    data       Variable length data depending on the type and code
    ========== =========================================================

    ``type`` attribute corresponds to ``type_`` parameter of __init__.

    Types and codes are defined in ``ryu.ofproto.ofproto``.

    ============================= ===========
    Type                          Code
    ============================= ===========
    OFPET_HELLO_FAILED            OFPHFC_*
    OFPET_BAD_REQUEST             OFPBRC_*
    OFPET_BAD_ACTION              OFPBAC_*
    OFPET_BAD_INSTRUCTION         OFPBIC_*
    OFPET_BAD_MATCH               OFPBMC_*
    OFPET_FLOW_MOD_FAILED         OFPFMFC_*
    OFPET_GROUP_MOD_FAILED        OFPGMFC_*
    OFPET_PORT_MOD_FAILED         OFPPMFC_*
    OFPET_TABLE_MOD_FAILED        OFPTMFC_*
    OFPET_QUEUE_OP_FAILED         OFPQOFC_*
    OFPET_SWITCH_CONFIG_FAILED    OFPSCFC_*
    OFPET_ROLE_REQUEST_FAILED     OFPRRFC_*
    OFPET_METER_MOD_FAILED        OFPMMFC_*
    OFPET_TABLE_FEATURES_FAILED   OFPTFFC_*
    OFPET_EXPERIMENTER            N/A
    ============================= ===========

    Example::

        @set_ev_cls(ofp_event.EventOFPErrorMsg,
                    [HANDSHAKE_DISPATCHER, CONFIG_DISPATCHER, MAIN_DISPATCHER])
        def error_msg_handler(self, ev):
            msg = ev.msg

            self.logger.debug('OFPErrorMsg received: type=0x%02x code=0x%02x '
                              'message=%s',
                              msg.type, msg.code, utils.hex_array(msg.data))
    """
    def __init__(self, datapath, type_=None, code=None, data=None):
        super(OFPErrorMsg, self).__init__(datapath)
        self.type = type_
        self.code = code
        self.data = data

    @classmethod
    def parser(cls, datapath, version, msg_type, msg_len, xid, buf):
        type_, = struct.unpack_from('!H', buffer(buf),
                                    ofproto.OFP_HEADER_SIZE)
        if type_ == ofproto.OFPET_EXPERIMENTER:
            return OFPErrorExperimenterMsg.parser(datapath, version, msg_type,
                                                  msg_len, xid, buf)
        msg = super(OFPErrorMsg, cls).parser(datapath, version, msg_type,
                                             msg_len, xid, buf)
        msg.type, msg.code = struct.unpack_from(
            ofproto.OFP_ERROR_MSG_PACK_STR, msg.buf,
            ofproto.OFP_HEADER_SIZE)
        msg.data = msg.buf[ofproto.OFP_ERROR_MSG_SIZE:]
        return msg

    def _serialize_body(self):
        assert self.data is not None
        msg_pack_into(ofproto.OFP_ERROR_MSG_PACK_STR, self.buf,
                      ofproto.OFP_HEADER_SIZE, self.type, self.code)
        self.buf += self.data


class OFPErrorExperimenterMsg(MsgBase):
    def __init__(self, datapath, type_=None, exp_type=None, experimenter=None,
                 data=None):
        super(OFPErrorExperimenterMsg, self).__init__(datapath)
        self.type = ofproto.OFPET_EXPERIMENTER
        self.exp_type = exp_type
        self.experimenter = experimenter
        self.data = data

    @classmethod
    def parser(cls, datapath, version, msg_type, msg_len, xid, buf):
        cls.cls_msg_type = msg_type
        msg = super(OFPErrorExperimenterMsg, cls).parser(
            datapath, version, msg_type, msg_len, xid, buf)
        msg.type, msg.exp_type, msg.experimenter = struct.unpack_from(
            ofproto.OFP_ERROR_EXPERIMENTER_MSG_PACK_STR, msg.buf,
            ofproto.OFP_HEADER_SIZE)
        msg.data = msg.buf[ofproto.OFP_ERROR_EXPERIMENTER_MSG_SIZE:]
        return msg

    def _serialize_body(self):
        assert self.data is not None
        msg_pack_into(ofproto.OFP_ERROR_EXPERIMENTER_MSG_PACK_STR,
                      self.buf, ofproto.OFP_HEADER_SIZE,
                      self.type, self.exp_type, self.experimenter)
        self.buf += self.data


@_register_parser
@_set_msg_type(ofproto.OFPT_ECHO_REQUEST)
class OFPEchoRequest(MsgBase):
    """
    Echo request message

    This message is handled by the Ryu framework, so the Ryu application
    do not need to process this typically.

    ========== =========================================================
    Attribute  Description
    ========== =========================================================
    data       An arbitrary length data
    ========== =========================================================

    Example::

        def send_echo_request(self, datapath, data):
            ofp = datapath.ofproto
            ofp_parser = datapath.ofproto_parser

            req = ofp_parser.OFPEchoRequest(datapath, data)
            datapath.send_msg(req)

        @set_ev_cls(ofp_event.EventOFPEchoRequest,
                    [HANDSHAKE_DISPATCHER, CONFIG_DISPATCHER, MAIN_DISPATCHER])
        def echo_request_handler(self, ev):
            self.logger.debug('OFPEchoRequest received: data=%s',
                              utils.hex_array(ev.msg.data))
    """
    def __init__(self, datapath, data=None):
        super(OFPEchoRequest, self).__init__(datapath)
        self.data = data

    @classmethod
    def parser(cls, datapath, version, msg_type, msg_len, xid, buf):
        msg = super(OFPEchoRequest, cls).parser(datapath, version, msg_type,
                                                msg_len, xid, buf)
        msg.data = msg.buf[ofproto.OFP_HEADER_SIZE:]
        return msg

    def _serialize_body(self):
        if self.data is not None:
            self.buf += self.data


@_register_parser
@_set_msg_type(ofproto.OFPT_ECHO_REPLY)
class OFPEchoReply(MsgBase):
    """
    Echo reply message

    This message is handled by the Ryu framework, so the Ryu application
    do not need to process this typically.

    ========== =========================================================
    Attribute  Description
    ========== =========================================================
    data       An arbitrary length data
    ========== =========================================================

    Example::

        def send_echo_reply(self, datapath, data):
            ofp = datapath.ofproto
            ofp_parser = datapath.ofproto_parser

            reply = ofp_parser.OFPEchoReply(datapath, data)
            datapath.send_msg(reply)

        @set_ev_cls(ofp_event.EventOFPEchoReply,
                    [HANDSHAKE_DISPATCHER, CONFIG_DISPATCHER, MAIN_DISPATCHER])
        def echo_reply_handler(self, ev):
            self.logger.debug('OFPEchoReply received: data=%s',
                              utils.hex_array(ev.msg.data))
    """
    def __init__(self, datapath, data=None):
        super(OFPEchoReply, self).__init__(datapath)
        self.data = data

    @classmethod
    def parser(cls, datapath, version, msg_type, msg_len, xid, buf):
        msg = super(OFPEchoReply, cls).parser(datapath, version, msg_type,
                                              msg_len, xid, buf)
        msg.data = msg.buf[ofproto.OFP_HEADER_SIZE:]
        return msg

    def _serialize_body(self):
        assert self.data is not None
        self.buf += self.data


@_register_parser
@_set_msg_type(ofproto.OFPT_EXPERIMENTER)
class OFPExperimenter(MsgBase):
    """
    Experimenter extension message

    ============= =========================================================
    Attribute     Description
    ============= =========================================================
    experimenter  Experimenter ID
    exp_type      Experimenter defined
    data          Experimenter defined arbitrary additional data
    ============= =========================================================
    """
    def __init__(self, datapath, experimenter=None, exp_type=None, data=None):
        super(OFPExperimenter, self).__init__(datapath)
        self.experimenter = experimenter
        self.exp_type = exp_type
        self.data = data

    @classmethod
    def parser(cls, datapath, version, msg_type, msg_len, xid, buf):
        msg = super(OFPExperimenter, cls).parser(datapath, version,
                                                 msg_type, msg_len,
                                                 xid, buf)
        (msg.experimenter, msg.exp_type) = struct.unpack_from(
            ofproto.OFP_EXPERIMENTER_HEADER_PACK_STR, msg.buf,
            ofproto.OFP_HEADER_SIZE)
        msg.data = msg.buf[ofproto.OFP_EXPERIMENTER_HEADER_SIZE:]

        return msg

    def _serialize_body(self):
        assert self.data is not None
        msg_pack_into(ofproto.OFP_EXPERIMENTER_HEADER_PACK_STR,
                      self.buf, ofproto.OFP_HEADER_SIZE,
                      self.experimenter, self.exp_type)
        self.buf += self.data


@_set_msg_type(ofproto.OFPT_FEATURES_REQUEST)
class OFPFeaturesRequest(MsgBase):
    """
    Features request message

    The controller sends a feature request to the switch upon session
    establishment.

    This message is handled by the Ryu framework, so the Ryu application
    do not need to process this typically.

    Example::

        def send_features_request(self, datapath):
            ofp_parser = datapath.ofproto_parser

            req = ofp_parser.OFPFeaturesRequest(datapath)
            datapath.send_msg(req)
    """
    def __init__(self, datapath):
        super(OFPFeaturesRequest, self).__init__(datapath)


@_register_parser
@_set_msg_type(ofproto.OFPT_FEATURES_REPLY)
class OFPSwitchFeatures(MsgBase):
    """
    Features reply message

    The switch responds with a features reply message to a features
    request.

    This message is handled by the Ryu framework, so the Ryu application
    do not need to process this typically.

    Example::

        @set_ev_cls(ofp_event.EventOFPSwitchFeatures, CONFIG_DISPATCHER)
        def switch_features_handler(self, ev):
            msg = ev.msg

            self.logger.debug('OFPSwitchFeatures received: '
                              'datapath_id=0x%016x n_buffers=%d '
                              'n_tables=%d auxiliary_id=%d '
                              'capabilities=0x%08x',
                              msg.datapath_id, msg.n_buffers, msg.n_tables,
                              msg.auxiliary_id, msg.capabilities)
    """
    def __init__(self, datapath, datapath_id=None, n_buffers=None,
                 n_tables=None, auxiliary_id=None, capabilities=None):
        super(OFPSwitchFeatures, self).__init__(datapath)
        self.datapath_id = datapath_id
        self.n_buffers = n_buffers
        self.n_tables = n_tables
        self.auxiliary_id = auxiliary_id
        self.capabilities = capabilities

    @classmethod
    def parser(cls, datapath, version, msg_type, msg_len, xid, buf):
        msg = super(OFPSwitchFeatures, cls).parser(datapath, version, msg_type,
                                                   msg_len, xid, buf)
        (msg.datapath_id,
         msg.n_buffers,
         msg.n_tables,
         msg.auxiliary_id,
         msg.capabilities,
         msg._reserved) = struct.unpack_from(
            ofproto.OFP_SWITCH_FEATURES_PACK_STR, msg.buf,
            ofproto.OFP_HEADER_SIZE)
        return msg


@_set_msg_type(ofproto.OFPT_GET_CONFIG_REQUEST)
class OFPGetConfigRequest(MsgBase):
    """
    Get config request message

    The controller sends a get config request to query configuration
    parameters in the switch.

    Example::

        def send_get_config_request(self, datapath):
            ofp_parser = datapath.ofproto_parser

            req = ofp_parser.OFPGetConfigRequest(datapath)
            datapath.send_msg(req)
    """
    def __init__(self, datapath):
        super(OFPGetConfigRequest, self).__init__(datapath)


@_register_parser
@_set_msg_type(ofproto.OFPT_GET_CONFIG_REPLY)
class OFPGetConfigReply(MsgBase):
    """
    Get config reply message

    The switch responds to a configuration request with a get config reply
    message.

    ============= =========================================================
    Attribute     Description
    ============= =========================================================
    flags         Bitmap of the following flags.

                  | OFPC_FRAG_NORMAL
                  | OFPC_FRAG_DROP
                  | OFPC_FRAG_REASM
                  | OFPC_FRAG_MASK
    miss_send_len Max bytes of new flow that datapath should send to the
                  controller
    ============= =========================================================

    Example::

        @set_ev_cls(ofp_event.EventOFPGetConfigReply, MAIN_DISPATCHER)
        def get_config_reply_handler(self, ev):
            msg = ev.msg
            dp = msg.datapath
            ofp = dp.ofproto
            flags = []

            if msg.flags & ofp.OFPC_FRAG_NORMAL:
                flags.append('NORMAL')
            if msg.flags & ofp.OFPC_FRAG_DROP:
                flags.append('DROP')
            if msg.flags & ofp.OFPC_FRAG_REASM:
                flags.append('REASM')
            self.logger.debug('OFPGetConfigReply received: '
                              'flags=%s miss_send_len=%d',
                              ','.join(flags), msg.miss_send_len)
    """
    def __init__(self, datapath, flags=None, miss_send_len=None):
        super(OFPGetConfigReply, self).__init__(datapath)
        self.flags = flags
        self.miss_send_len = miss_send_len

    @classmethod
    def parser(cls, datapath, version, msg_type, msg_len, xid, buf):
        msg = super(OFPGetConfigReply, cls).parser(datapath, version, msg_type,
                                                   msg_len, xid, buf)
        msg.flags, msg.miss_send_len = struct.unpack_from(
            ofproto.OFP_SWITCH_CONFIG_PACK_STR, msg.buf,
            ofproto.OFP_HEADER_SIZE)
        return msg


@_set_msg_type(ofproto.OFPT_SET_CONFIG)
class OFPSetConfig(MsgBase):
    """
    Set config request message

    The controller sends a set config request message to set configuraion
    parameters.

    ============= =========================================================
    Attribute     Description
    ============= =========================================================
    flags         Bitmap of the following flags.

                  | OFPC_FRAG_NORMAL
                  | OFPC_FRAG_DROP
                  | OFPC_FRAG_REASM
    miss_send_len Max bytes of new flow that datapath should send to the
                  controller
    ============= =========================================================

    Example::

        def send_set_config(self, datapath):
            ofp = datapath.ofproto
            ofp_parser = datapath.ofproto_parser

            req = ofp_parser.OFPSetConfig(datapath, ofp.OFPC_FRAG_NORMAL, 256)
            datapath.send_msg(req)
    """
    def __init__(self, datapath, flags=0, miss_send_len=0):
        super(OFPSetConfig, self).__init__(datapath)
        self.flags = flags
        self.miss_send_len = miss_send_len

    def _serialize_body(self):
        assert self.flags is not None
        assert self.miss_send_len is not None
        msg_pack_into(ofproto.OFP_SWITCH_CONFIG_PACK_STR,
                      self.buf, ofproto.OFP_HEADER_SIZE,
                      self.flags, self.miss_send_len)


UINT64_MAX = (1 << 64) - 1
UINT32_MAX = (1 << 32) - 1
UINT16_MAX = (1 << 16) - 1


class Flow(object):
    def __init__(self):
        self.in_port = 0
        self.in_phy_port = 0
        self.metadata = 0
        self.dl_dst = mac.DONTCARE
        self.dl_src = mac.DONTCARE
        self.dl_type = 0
        self.vlan_vid = 0
        self.vlan_pcp = 0
        self.ip_dscp = 0
        self.ip_ecn = 0
        self.ip_proto = 0
        self.ipv4_src = 0
        self.ipv4_dst = 0
        self.tcp_src = 0
        self.tcp_dst = 0
        self.udp_src = 0
        self.udp_dst = 0
        self.sctp_src = 0
        self.sctp_dst = 0
        self.icmpv4_type = 0
        self.icmpv4_code = 0
        self.arp_op = 0
        self.arp_spa = 0
        self.arp_tpa = 0
        self.arp_sha = 0
        self.arp_tha = 0
        self.ipv6_src = []
        self.ipv6_dst = []
        self.ipv6_flabel = 0
        self.icmpv6_type = 0
        self.icmpv6_code = 0
        self.ipv6_nd_target = []
        self.ipv6_nd_sll = 0
        self.ipv6_nd_tll = 0
        self.mpls_label = 0
        self.mpls_tc = 0
        self.mpls_bos = 0
        self.pbb_isid = 0
        self.tunnel_id = 0
        self.ipv6_exthdr = 0


class FlowWildcards(object):
    def __init__(self):
        self.metadata_mask = 0
        self.dl_dst_mask = 0
        self.dl_src_mask = 0
        self.vlan_vid_mask = 0
        self.ipv4_src_mask = 0
        self.ipv4_dst_mask = 0
        self.arp_spa_mask = 0
        self.arp_tpa_mask = 0
        self.arp_sha_mask = 0
        self.arp_tha_mask = 0
        self.ipv6_src_mask = []
        self.ipv6_dst_mask = []
        self.ipv6_flabel_mask = 0
        self.pbb_isid_mask = 0
        self.tunnel_id_mask = 0
        self.ipv6_exthdr_mask = 0
        self.wildcards = (1 << 64) - 1

    def ft_set(self, shift):
        self.wildcards &= ~(1 << shift)

    def ft_test(self, shift):
        return not self.wildcards & (1 << shift)


class OFPMatch(StringifyMixin):
    """
    Flow Match Structure

    This class is implementation of the flow match structure having
    compose/query API.
    There are new API and old API for compatibility. the old API is
    supposed to be removed later.

    You can define the flow match by the keyword arguments.
    The following arguments are available.

    ================ =============== ==================================
    Argument         Value           Description
    ================ =============== ==================================
    in_port          Integer 32bit   Switch input port
    in_phy_port      Integer 32bit   Switch physical input port
    metadata         Integer 64bit   Metadata passed between tables
    eth_dst          MAC address     Ethernet destination address
    eth_src          MAC address     Ethernet source address
    eth_type         Integer 16bit   Ethernet frame type
    vlan_vid         Integer 16bit   VLAN id
    vlan_pcp         Integer 8bit    VLAN priority
    ip_dscp          Integer 8bit    IP DSCP (6 bits in ToS field)
    ip_ecn           Integer 8bit    IP ECN (2 bits in ToS field)
    ip_proto         Integer 8bit    IP protocol
    ipv4_src         IPv4 address    IPv4 source address
    ipv4_dst         IPv4 address    IPv4 destination address
    tcp_src          Integer 16bit   TCP source port
    tcp_dst          Integer 16bit   TCP destination port
    udp_src          Integer 16bit   UDP source port
    udp_dst          Integer 16bit   UDP destination port
    sctp_src         Integer 16bit   SCTP source port
    sctp_dst         Integer 16bit   SCTP destination port
    icmpv4_type      Integer 8bit    ICMP type
    icmpv4_code      Integer 8bit    ICMP code
    arp_op           Integer 16bit   ARP opcode
    arp_spa          IPv4 address    ARP source IPv4 address
    arp_tpa          IPv4 address    ARP target IPv4 address
    arp_sha          MAC address     ARP source hardware address
    arp_tha          MAC address     ARP target hardware address
    ipv6_src         IPv6 address    IPv6 source address
    ipv6_dst         IPv6 address    IPv6 destination address
    ipv6_flabel      Integer 32bit   IPv6 Flow Label
    icmpv6_type      Integer 8bit    ICMPv6 type
    icmpv6_code      Integer 8bit    ICMPv6 code
    ipv6_nd_target   IPv6 address    Target address for ND
    ipv6_nd_sll      MAC address     Source link-layer for ND
    ipv6_nd_tll      MAC address     Target link-layer for ND
    mpls_label       Integer 32bit   MPLS label
    mpls_tc          Integer 8bit    MPLS TC
    mpls_bos         Integer 8bit    MPLS BoS bit
    pbb_isid         Integer 24bit   PBB I-SID
    tunnel_id        Integer 64bit   Logical Port Metadata
    ipv6_exthdr      Integer 16bit   IPv6 Extension Header pseudo-field
    ================ =============== ==================================

    Example::

        >>> # compose
        >>> match = parser.OFPMatch(
        ...     in_port=1,
        ...     eth_type=0x86dd,
        ...     ipv6_src=('2001:db8:bd05:1d2:288a:1fc0:1:10ee',
        ...               'ffff:ffff:ffff:ffff::'),
        ...     ipv6_dst='2001:db8:bd05:1d2:288a:1fc0:1:10ee')
        >>> # query
        >>> if 'ipv6_src' in match:
        ...     print match['ipv6_src']
        ...
        ('2001:db8:bd05:1d2:288a:1fc0:1:10ee', 'ffff:ffff:ffff:ffff::')
    """

    def __init__(self, type_=None, length=None, _ordered_fields=None,
                 **kwargs):
        """
        You can define the flow match by the keyword arguments.
        Please refer to ofproto.oxm_types for the key which you can
        define.
        """
        super(OFPMatch, self).__init__()
        self._wc = FlowWildcards()
        self._flow = Flow()
        self.fields = []
        self.type = ofproto.OFPMT_OXM
        self.length = length

        if _ordered_fields is not None:
            assert not kwargs
            self._fields2 = _ordered_fields
        else:
            # eg.
            #   OFPMatch(eth_src=('ff:ff:ff:00:00:00'), eth_type=0x800,
            #            ipv4_src='10.0.0.1')
            #kwargs = dict(ofproto.oxm_normalize_user(k, v) for
            #              (k, v) in kwargs.iteritems())
            #fields = [ofproto.oxm_from_user(k, v) for (k, v)
            #          in kwargs.iteritems()]
	    kwargs = dict(ofproto.oxm_normalize_user(k, v) for
                          (k, v) in kwargs.iteritems() if v is not None) #BINH: filter out key with None value
            fields = [ofproto.oxm_from_user(k, v) for (k, v)
                      in kwargs.iteritems() if v is not None] #BINH: filter out key with None value
            # assumption: sorting by OXM type values makes fields
            # meet ordering requirements (eg. eth_type before ipv4_src)
            fields.sort()
            self._fields2 = [ofproto.oxm_to_user(n, v, m) for (n, v, m)
                             in fields]

    def __getitem__(self, key):
        return dict(self._fields2)[key]

    def __contains__(self, key):
        return key in dict(self._fields2)

    def iteritems(self):
        return dict(self._fields2).iteritems()

    def get(self, key, default=None):
        return dict(self._fields2).get(key, default)

    def stringify_attrs(self):
        yield "oxm_fields", dict(self._fields2)

    def to_jsondict(self):
        """
        Returns a dict expressing the flow match.
        """
        # XXX old api compat
        if self._composed_with_old_api():
            # copy object first because serialize_old is destructive
            o2 = OFPMatch()
            o2.fields = self.fields[:]
            # serialize and parse to fill OFPMatch._fields2
            buf = bytearray()
            o2.serialize(buf, 0)
            o = OFPMatch.parser(str(buf), 0)
        else:
            o = self

        body = {"oxm_fields": [ofproto.oxm_to_jsondict(k, uv) for k, uv
                               in o._fields2],
                "length": o.length,
                "type": o.type}
        return {self.__class__.__name__: body}

    @classmethod
    def from_jsondict(cls, dict_):
        """
        Returns an object which is generated from a dict.

        Exception raises:
        KeyError -- Unknown match field is defined in dict
        """
        fields = [ofproto.oxm_from_jsondict(f) for f
                  in dict_['oxm_fields']]
        o = OFPMatch(_ordered_fields=fields)
        # XXX old api compat
        # serialize and parse to fill OFPMatch.fields
        buf = bytearray()
        o.serialize(buf, 0)
        return OFPMatch.parser(str(buf), 0)

    def __str__(self):
        # XXX old api compat
        if self._composed_with_old_api():
            # copy object first because serialize_old is destructive
            o2 = OFPMatch()
            o2.fields = self.fields[:]
            # serialize and parse to fill OFPMatch._fields2
            buf = bytearray()
            o2.serialize(buf, 0)
            o = OFPMatch.parser(str(buf), 0)
        else:
            o = self
        return super(OFPMatch, o).__str__()

    __repr__ = __str__

    def append_field(self, header, value, mask=None):
        """
        Append a match field.

        ========= =======================================================
        Argument  Description
        ========= =======================================================
        header    match field header ID which is defined automatically in
                  ``ofproto``
        value     match field value
        mask      mask value to the match field
        ========= =======================================================

        The available ``header`` is as follows.

        ====================== ===================================
        Header ID              Description
        ====================== ===================================
        OXM_OF_IN_PORT         Switch input port
        OXM_OF_IN_PHY_PORT     Switch physical input port
        OXM_OF_METADATA        Metadata passed between tables
        OXM_OF_ETH_DST         Ethernet destination address
        OXM_OF_ETH_SRC         Ethernet source address
        OXM_OF_ETH_TYPE        Ethernet frame type
        OXM_OF_VLAN_VID        VLAN id
        OXM_OF_VLAN_PCP        VLAN priority
        OXM_OF_IP_DSCP         IP DSCP (6 bits in ToS field)
        OXM_OF_IP_ECN          IP ECN (2 bits in ToS field)
        OXM_OF_IP_PROTO        IP protocol
        OXM_OF_IPV4_SRC        IPv4 source address
        OXM_OF_IPV4_DST        IPv4 destination address
        OXM_OF_TCP_SRC         TCP source port
        OXM_OF_TCP_DST         TCP destination port
        OXM_OF_UDP_SRC         UDP source port
        OXM_OF_UDP_DST         UDP destination port
        OXM_OF_SCTP_SRC        SCTP source port
        OXM_OF_SCTP_DST        SCTP destination port
        OXM_OF_ICMPV4_TYPE     ICMP type
        OXM_OF_ICMPV4_CODE     ICMP code
        OXM_OF_ARP_OP          ARP opcode
        OXM_OF_ARP_SPA         ARP source IPv4 address
        OXM_OF_ARP_TPA         ARP target IPv4 address
        OXM_OF_ARP_SHA         ARP source hardware address
        OXM_OF_ARP_THA         ARP target hardware address
        OXM_OF_IPV6_SRC        IPv6 source address
        OXM_OF_IPV6_DST        IPv6 destination address
        OXM_OF_IPV6_FLABEL     IPv6 Flow Label
        OXM_OF_ICMPV6_TYPE     ICMPv6 type
        OXM_OF_ICMPV6_CODE     ICMPv6 code
        OXM_OF_IPV6_ND_TARGET  Target address for ND
        OXM_OF_IPV6_ND_SLL     Source link-layer for ND
        OXM_OF_IPV6_ND_TLL     Target link-layer for ND
        OXM_OF_MPLS_LABEL      MPLS label
        OXM_OF_MPLS_TC         MPLS TC
        OXM_OF_MPLS_BOS        MPLS BoS bit
        OXM_OF_PBB_ISID        PBB I-SID
        OXM_OF_TUNNEL_ID       Logical Port Metadata
        OXM_OF_IPV6_EXTHDR     IPv6 Extension Header pseudo-field
        ====================== ===================================
        """
        self.fields.append(OFPMatchField.make(header, value, mask))

    def _composed_with_old_api(self):
        return (self.fields and not self._fields2) or \
            self._wc.__dict__ != FlowWildcards().__dict__

    def serialize(self, buf, offset):
        """
        Outputs the expression of the wire protocol of the flow match into
        the buf.
        Returns the output length.
        """
        # XXX compat
        if self._composed_with_old_api():
            return self.serialize_old(buf, offset)

        fields = [ofproto.oxm_from_user(k, uv) for (k, uv)
                  in self._fields2]

        hdr_pack_str = '!HH'
        field_offset = offset + struct.calcsize(hdr_pack_str)
        for (n, value, mask) in fields:
            field_offset += ofproto.oxm_serialize(n, value, mask, buf,
                                                  field_offset)

        length = field_offset - offset
        msg_pack_into(hdr_pack_str, buf, offset,
                      ofproto.OFPMT_OXM, length)
        self.length = length

        pad_len = utils.round_up(length, 8) - length
        ofproto_parser.msg_pack_into("%dx" % pad_len, buf, field_offset)

        return length + pad_len

    def serialize_old(self, buf, offset):
        if hasattr(self, '_serialized'):
            raise Exception('serializing an OFPMatch composed with '
                            'old API multiple times is not supported')
        self._serialized = True

        if self._wc.ft_test(ofproto.OFPXMT_OFB_IN_PORT):
            self.append_field(ofproto.OXM_OF_IN_PORT,
                              self._flow.in_port)

        if self._wc.ft_test(ofproto.OFPXMT_OFB_IN_PHY_PORT):
            self.append_field(ofproto.OXM_OF_IN_PHY_PORT,
                              self._flow.in_phy_port)

        if self._wc.ft_test(ofproto.OFPXMT_OFB_METADATA):
            if self._wc.metadata_mask == UINT64_MAX:
                header = ofproto.OXM_OF_METADATA
            else:
                header = ofproto.OXM_OF_METADATA_W
            self.append_field(header, self._flow.metadata,
                              self._wc.metadata_mask)

        if self._wc.ft_test(ofproto.OFPXMT_OFB_ETH_DST):
            if self._wc.dl_dst_mask:
                header = ofproto.OXM_OF_ETH_DST_W
            else:
                header = ofproto.OXM_OF_ETH_DST
            self.append_field(header, self._flow.dl_dst, self._wc.dl_dst_mask)

        if self._wc.ft_test(ofproto.OFPXMT_OFB_ETH_SRC):
            if self._wc.dl_src_mask:
                header = ofproto.OXM_OF_ETH_SRC_W
            else:
                header = ofproto.OXM_OF_ETH_SRC
            self.append_field(header, self._flow.dl_src, self._wc.dl_src_mask)

        if self._wc.ft_test(ofproto.OFPXMT_OFB_ETH_TYPE):
            self.append_field(ofproto.OXM_OF_ETH_TYPE, self._flow.dl_type)

        if self._wc.ft_test(ofproto.OFPXMT_OFB_VLAN_VID):
            if self._wc.vlan_vid_mask == UINT16_MAX:
                header = ofproto.OXM_OF_VLAN_VID
            else:
                header = ofproto.OXM_OF_VLAN_VID_W
            self.append_field(header, self._flow.vlan_vid,
                              self._wc.vlan_vid_mask)

        if self._wc.ft_test(ofproto.OFPXMT_OFB_VLAN_PCP):
            self.append_field(ofproto.OXM_OF_VLAN_PCP,
                              self._flow.vlan_pcp)

        if self._wc.ft_test(ofproto.OFPXMT_OFB_IP_DSCP):
            self.append_field(ofproto.OXM_OF_IP_DSCP, self._flow.ip_dscp)

        if self._wc.ft_test(ofproto.OFPXMT_OFB_IP_ECN):
            self.append_field(ofproto.OXM_OF_IP_ECN, self._flow.ip_ecn)

        if self._wc.ft_test(ofproto.OFPXMT_OFB_IP_PROTO):
            self.append_field(ofproto.OXM_OF_IP_PROTO,
                              self._flow.ip_proto)

        if self._wc.ft_test(ofproto.OFPXMT_OFB_IPV4_SRC):
            if self._wc.ipv4_src_mask == UINT32_MAX:
                header = ofproto.OXM_OF_IPV4_SRC
            else:
                header = ofproto.OXM_OF_IPV4_SRC_W
            self.append_field(header, self._flow.ipv4_src,
                              self._wc.ipv4_src_mask)

        if self._wc.ft_test(ofproto.OFPXMT_OFB_IPV4_DST):
            if self._wc.ipv4_dst_mask == UINT32_MAX:
                header = ofproto.OXM_OF_IPV4_DST
            else:
                header = ofproto.OXM_OF_IPV4_DST_W
            self.append_field(header, self._flow.ipv4_dst,
                              self._wc.ipv4_dst_mask)

        if self._wc.ft_test(ofproto.OFPXMT_OFB_TCP_SRC):
            self.append_field(ofproto.OXM_OF_TCP_SRC, self._flow.tcp_src)

        if self._wc.ft_test(ofproto.OFPXMT_OFB_TCP_DST):
            self.append_field(ofproto.OXM_OF_TCP_DST, self._flow.tcp_dst)

        if self._wc.ft_test(ofproto.OFPXMT_OFB_UDP_SRC):
            self.append_field(ofproto.OXM_OF_UDP_SRC, self._flow.udp_src)

        if self._wc.ft_test(ofproto.OFPXMT_OFB_UDP_DST):
            self.append_field(ofproto.OXM_OF_UDP_DST, self._flow.udp_dst)

        if self._wc.ft_test(ofproto.OFPXMT_OFB_SCTP_SRC):
            self.append_field(ofproto.OXM_OF_SCTP_SRC,
                              self._flow.sctp_src)

        if self._wc.ft_test(ofproto.OFPXMT_OFB_SCTP_DST):
            self.append_field(ofproto.OXM_OF_SCTP_DST,
                              self._flow.sctp_dst)

        if self._wc.ft_test(ofproto.OFPXMT_OFB_ICMPV4_TYPE):
            self.append_field(ofproto.OXM_OF_ICMPV4_TYPE,
                              self._flow.icmpv4_type)

        if self._wc.ft_test(ofproto.OFPXMT_OFB_ICMPV4_CODE):
            self.append_field(ofproto.OXM_OF_ICMPV4_CODE,
                              self._flow.icmpv4_code)

        if self._wc.ft_test(ofproto.OFPXMT_OFB_ARP_OP):
            self.append_field(ofproto.OXM_OF_ARP_OP, self._flow.arp_op)

        if self._wc.ft_test(ofproto.OFPXMT_OFB_ARP_SPA):
            if self._wc.arp_spa_mask == UINT32_MAX:
                header = ofproto.OXM_OF_ARP_SPA
            else:
                header = ofproto.OXM_OF_ARP_SPA_W
            self.append_field(header, self._flow.arp_spa,
                              self._wc.arp_spa_mask)

        if self._wc.ft_test(ofproto.OFPXMT_OFB_ARP_TPA):
            if self._wc.arp_tpa_mask == UINT32_MAX:
                header = ofproto.OXM_OF_ARP_TPA
            else:
                header = ofproto.OXM_OF_ARP_TPA_W
            self.append_field(header, self._flow.arp_tpa,
                              self._wc.arp_tpa_mask)

        if self._wc.ft_test(ofproto.OFPXMT_OFB_ARP_SHA):
            if self._wc.arp_sha_mask:
                header = ofproto.OXM_OF_ARP_SHA_W
            else:
                header = ofproto.OXM_OF_ARP_SHA
            self.append_field(header, self._flow.arp_sha,
                              self._wc.arp_sha_mask)

        if self._wc.ft_test(ofproto.OFPXMT_OFB_ARP_THA):
            if self._wc.arp_tha_mask:
                header = ofproto.OXM_OF_ARP_THA_W
            else:
                header = ofproto.OXM_OF_ARP_THA
            self.append_field(header, self._flow.arp_tha,
                              self._wc.arp_tha_mask)

        if self._wc.ft_test(ofproto.OFPXMT_OFB_IPV6_SRC):
            if len(self._wc.ipv6_src_mask):
                header = ofproto.OXM_OF_IPV6_SRC_W
            else:
                header = ofproto.OXM_OF_IPV6_SRC
            self.append_field(header, self._flow.ipv6_src,
                              self._wc.ipv6_src_mask)

        if self._wc.ft_test(ofproto.OFPXMT_OFB_IPV6_DST):
            if len(self._wc.ipv6_dst_mask):
                header = ofproto.OXM_OF_IPV6_DST_W
            else:
                header = ofproto.OXM_OF_IPV6_DST
            self.append_field(header, self._flow.ipv6_dst,
                              self._wc.ipv6_dst_mask)

        if self._wc.ft_test(ofproto.OFPXMT_OFB_IPV6_FLABEL):
            if self._wc.ipv6_flabel_mask == UINT32_MAX:
                header = ofproto.OXM_OF_IPV6_FLABEL
            else:
                header = ofproto.OXM_OF_IPV6_FLABEL_W
            self.append_field(header, self._flow.ipv6_flabel,
                              self._wc.ipv6_flabel_mask)

        if self._wc.ft_test(ofproto.OFPXMT_OFB_ICMPV6_TYPE):
            self.append_field(ofproto.OXM_OF_ICMPV6_TYPE,
                              self._flow.icmpv6_type)

        if self._wc.ft_test(ofproto.OFPXMT_OFB_ICMPV6_CODE):
            self.append_field(ofproto.OXM_OF_ICMPV6_CODE,
                              self._flow.icmpv6_code)

        if self._wc.ft_test(ofproto.OFPXMT_OFB_IPV6_ND_TARGET):
            self.append_field(ofproto.OXM_OF_IPV6_ND_TARGET,
                              self._flow.ipv6_nd_target)

        if self._wc.ft_test(ofproto.OFPXMT_OFB_IPV6_ND_SLL):
            self.append_field(ofproto.OXM_OF_IPV6_ND_SLL,
                              self._flow.ipv6_nd_sll)

        if self._wc.ft_test(ofproto.OFPXMT_OFB_IPV6_ND_TLL):
            self.append_field(ofproto.OXM_OF_IPV6_ND_TLL,
                              self._flow.ipv6_nd_tll)

        if self._wc.ft_test(ofproto.OFPXMT_OFB_MPLS_LABEL):
            self.append_field(ofproto.OXM_OF_MPLS_LABEL,
                              self._flow.mpls_label)

        if self._wc.ft_test(ofproto.OFPXMT_OFB_MPLS_TC):
            self.append_field(ofproto.OXM_OF_MPLS_TC,
                              self._flow.mpls_tc)

        if self._wc.ft_test(ofproto.OFPXMT_OFB_MPLS_BOS):
            self.append_field(ofproto.OXM_OF_MPLS_BOS,
                              self._flow.mpls_bos)

        if self._wc.ft_test(ofproto.OFPXMT_OFB_PBB_ISID):
            if self._wc.pbb_isid_mask:
                header = ofproto.OXM_OF_PBB_ISID_W
            else:
                header = ofproto.OXM_OF_PBB_ISID
            self.append_field(header, self._flow.pbb_isid,
                              self._wc.pbb_isid_mask)

        if self._wc.ft_test(ofproto.OFPXMT_OFB_TUNNEL_ID):
            if self._wc.tunnel_id_mask:
                header = ofproto.OXM_OF_TUNNEL_ID_W
            else:
                header = ofproto.OXM_OF_TUNNEL_ID
            self.append_field(header, self._flow.tunnel_id,
                              self._wc.tunnel_id_mask)

        if self._wc.ft_test(ofproto.OFPXMT_OFB_IPV6_EXTHDR):
            if self._wc.ipv6_exthdr_mask:
                header = ofproto.OXM_OF_IPV6_EXTHDR_W
            else:
                header = ofproto.OXM_OF_IPV6_EXTHDR
            self.append_field(header, self._flow.ipv6_exthdr,
                              self._wc.ipv6_exthdr_mask)

        field_offset = offset + 4
        for f in self.fields:
            f.serialize(buf, field_offset)
            field_offset += f.length

        length = field_offset - offset
        msg_pack_into('!HH', buf, offset, ofproto.OFPMT_OXM, length)

        pad_len = utils.round_up(length, 8) - length
        ofproto_parser.msg_pack_into("%dx" % pad_len, buf, field_offset)

        return length + pad_len

    @classmethod
    def parser(cls, buf, offset):
        """
        Returns an object which is generated from a buffer including the
        expression of the wire protocol of the flow match.
        """
        match = OFPMatch()
        type_, length = struct.unpack_from('!HH', buf, offset)

        match.type = type_
        match.length = length

        # ofp_match adjustment
        offset += 4
        length -= 4

        # XXXcompat
        cls.parser_old(match, buf, offset, length)

        fields = []
        while length > 0:
            n, value, mask, field_len = ofproto.oxm_parse(buf, offset)
            k, uv = ofproto.oxm_to_user(n, value, mask)
            fields.append((k, uv))
            offset += field_len
            length -= field_len
        match._fields2 = fields
        return match

    @staticmethod
    def parser_old(match, buf, offset, length):
        while length > 0:
            field = OFPMatchField.parser(buf, offset)
            offset += field.length
            length -= field.length
            match.fields.append(field)

    def set_in_port(self, port):
        self._wc.ft_set(ofproto.OFPXMT_OFB_IN_PORT)
        self._flow.in_port = port

    def set_in_phy_port(self, phy_port):
        self._wc.ft_set(ofproto.OFPXMT_OFB_IN_PHY_PORT)
        self._flow.in_phy_port = phy_port

    def set_metadata(self, metadata):
        self.set_metadata_masked(metadata, UINT64_MAX)

    def set_metadata_masked(self, metadata, mask):
        self._wc.ft_set(ofproto.OFPXMT_OFB_METADATA)
        self._wc.metadata_mask = mask
        self._flow.metadata = metadata & mask

    def set_dl_dst(self, dl_dst):
        self._wc.ft_set(ofproto.OFPXMT_OFB_ETH_DST)
        self._flow.dl_dst = dl_dst

    def set_dl_dst_masked(self, dl_dst, mask):
        self._wc.ft_set(ofproto.OFPXMT_OFB_ETH_DST)
        self._wc.dl_dst_mask = mask
        # bit-wise and of the corresponding elements of dl_dst and mask
        self._flow.dl_dst = mac.haddr_bitand(dl_dst, mask)

    def set_dl_src(self, dl_src):
        self._wc.ft_set(ofproto.OFPXMT_OFB_ETH_SRC)
        self._flow.dl_src = dl_src

    def set_dl_src_masked(self, dl_src, mask):
        self._wc.ft_set(ofproto.OFPXMT_OFB_ETH_SRC)
        self._wc.dl_src_mask = mask
        self._flow.dl_src = mac.haddr_bitand(dl_src, mask)

    def set_dl_type(self, dl_type):
        self._wc.ft_set(ofproto.OFPXMT_OFB_ETH_TYPE)
        self._flow.dl_type = dl_type

    def set_vlan_vid(self, vid):
        self.set_vlan_vid_masked(vid, UINT16_MAX)

    def set_vlan_vid_masked(self, vid, mask):
        self._wc.ft_set(ofproto.OFPXMT_OFB_VLAN_VID)
        self._wc.vlan_vid_mask = mask
        self._flow.vlan_vid = vid

    def set_vlan_pcp(self, pcp):
        self._wc.ft_set(ofproto.OFPXMT_OFB_VLAN_PCP)
        self._flow.vlan_pcp = pcp

    def set_ip_dscp(self, ip_dscp):
        self._wc.ft_set(ofproto.OFPXMT_OFB_IP_DSCP)
        self._flow.ip_dscp = ip_dscp

    def set_ip_ecn(self, ip_ecn):
        self._wc.ft_set(ofproto.OFPXMT_OFB_IP_ECN)
        self._flow.ip_ecn = ip_ecn

    def set_ip_proto(self, ip_proto):
        self._wc.ft_set(ofproto.OFPXMT_OFB_IP_PROTO)
        self._flow.ip_proto = ip_proto

    def set_ipv4_src(self, ipv4_src):
        self.set_ipv4_src_masked(ipv4_src, UINT32_MAX)

    def set_ipv4_src_masked(self, ipv4_src, mask):
        self._wc.ft_set(ofproto.OFPXMT_OFB_IPV4_SRC)
        self._flow.ipv4_src = ipv4_src
        self._wc.ipv4_src_mask = mask

    def set_ipv4_dst(self, ipv4_dst):
        self.set_ipv4_dst_masked(ipv4_dst, UINT32_MAX)

    def set_ipv4_dst_masked(self, ipv4_dst, mask):
        self._wc.ft_set(ofproto.OFPXMT_OFB_IPV4_DST)
        self._flow.ipv4_dst = ipv4_dst
        self._wc.ipv4_dst_mask = mask

    def set_tcp_src(self, tcp_src):
        self._wc.ft_set(ofproto.OFPXMT_OFB_TCP_SRC)
        self._flow.tcp_src = tcp_src

    def set_tcp_dst(self, tcp_dst):
        self._wc.ft_set(ofproto.OFPXMT_OFB_TCP_DST)
        self._flow.tcp_dst = tcp_dst

    def set_udp_src(self, udp_src):
        self._wc.ft_set(ofproto.OFPXMT_OFB_UDP_SRC)
        self._flow.udp_src = udp_src

    def set_udp_dst(self, udp_dst):
        self._wc.ft_set(ofproto.OFPXMT_OFB_UDP_DST)
        self._flow.udp_dst = udp_dst

    def set_sctp_src(self, sctp_src):
        self._wc.ft_set(ofproto.OFPXMT_OFB_SCTP_SRC)
        self._flow.sctp_src = sctp_src

    def set_sctp_dst(self, sctp_dst):
        self._wc.ft_set(ofproto.OFPXMT_OFB_SCTP_DST)
        self._flow.sctp_dst = sctp_dst

    def set_icmpv4_type(self, icmpv4_type):
        self._wc.ft_set(ofproto.OFPXMT_OFB_ICMPV4_TYPE)
        self._flow.icmpv4_type = icmpv4_type

    def set_icmpv4_code(self, icmpv4_code):
        self._wc.ft_set(ofproto.OFPXMT_OFB_ICMPV4_CODE)
        self._flow.icmpv4_code = icmpv4_code

    def set_arp_opcode(self, arp_op):
        self._wc.ft_set(ofproto.OFPXMT_OFB_ARP_OP)
        self._flow.arp_op = arp_op

    def set_arp_spa(self, arp_spa):
        self.set_arp_spa_masked(arp_spa, UINT32_MAX)

    def set_arp_spa_masked(self, arp_spa, mask):
        self._wc.ft_set(ofproto.OFPXMT_OFB_ARP_SPA)
        self._wc.arp_spa_mask = mask
        self._flow.arp_spa = arp_spa

    def set_arp_tpa(self, arp_tpa):
        self.set_arp_tpa_masked(arp_tpa, UINT32_MAX)

    def set_arp_tpa_masked(self, arp_tpa, mask):
        self._wc.ft_set(ofproto.OFPXMT_OFB_ARP_TPA)
        self._wc.arp_tpa_mask = mask
        self._flow.arp_tpa = arp_tpa

    def set_arp_sha(self, arp_sha):
        self._wc.ft_set(ofproto.OFPXMT_OFB_ARP_SHA)
        self._flow.arp_sha = arp_sha

    def set_arp_sha_masked(self, arp_sha, mask):
        self._wc.ft_set(ofproto.OFPXMT_OFB_ARP_SHA)
        self._wc.arp_sha_mask = mask
        self._flow.arp_sha = mac.haddr_bitand(arp_sha, mask)

    def set_arp_tha(self, arp_tha):
        self._wc.ft_set(ofproto.OFPXMT_OFB_ARP_THA)
        self._flow.arp_tha = arp_tha

    def set_arp_tha_masked(self, arp_tha, mask):
        self._wc.ft_set(ofproto.OFPXMT_OFB_ARP_THA)
        self._wc.arp_tha_mask = mask
        self._flow.arp_tha = mac.haddr_bitand(arp_tha, mask)

    def set_ipv6_src(self, src):
        self._wc.ft_set(ofproto.OFPXMT_OFB_IPV6_SRC)
        self._flow.ipv6_src = src

    def set_ipv6_src_masked(self, src, mask):
        self._wc.ft_set(ofproto.OFPXMT_OFB_IPV6_SRC)
        self._wc.ipv6_src_mask = mask
        self._flow.ipv6_src = [x & y for (x, y) in itertools.izip(src, mask)]

    def set_ipv6_dst(self, dst):
        self._wc.ft_set(ofproto.OFPXMT_OFB_IPV6_DST)
        self._flow.ipv6_dst = dst

    def set_ipv6_dst_masked(self, dst, mask):
        self._wc.ft_set(ofproto.OFPXMT_OFB_IPV6_DST)
        self._wc.ipv6_dst_mask = mask
        self._flow.ipv6_dst = [x & y for (x, y) in itertools.izip(dst, mask)]

    def set_ipv6_flabel(self, flabel):
        self.set_ipv6_flabel_masked(flabel, UINT32_MAX)

    def set_ipv6_flabel_masked(self, flabel, mask):
        self._wc.ft_set(ofproto.OFPXMT_OFB_IPV6_FLABEL)
        self._wc.ipv6_flabel_mask = mask
        self._flow.ipv6_flabel = flabel

    def set_icmpv6_type(self, icmpv6_type):
        self._wc.ft_set(ofproto.OFPXMT_OFB_ICMPV6_TYPE)
        self._flow.icmpv6_type = icmpv6_type

    def set_icmpv6_code(self, icmpv6_code):
        self._wc.ft_set(ofproto.OFPXMT_OFB_ICMPV6_CODE)
        self._flow.icmpv6_code = icmpv6_code

    def set_ipv6_nd_target(self, target):
        self._wc.ft_set(ofproto.OFPXMT_OFB_IPV6_ND_TARGET)
        self._flow.ipv6_nd_target = target

    def set_ipv6_nd_sll(self, ipv6_nd_sll):
        self._wc.ft_set(ofproto.OFPXMT_OFB_IPV6_ND_SLL)
        self._flow.ipv6_nd_sll = ipv6_nd_sll

    def set_ipv6_nd_tll(self, ipv6_nd_tll):
        self._wc.ft_set(ofproto.OFPXMT_OFB_IPV6_ND_TLL)
        self._flow.ipv6_nd_tll = ipv6_nd_tll

    def set_mpls_label(self, mpls_label):
        self._wc.ft_set(ofproto.OFPXMT_OFB_MPLS_LABEL)
        self._flow.mpls_label = mpls_label

    def set_mpls_tc(self, mpls_tc):
        self._wc.ft_set(ofproto.OFPXMT_OFB_MPLS_TC)
        self._flow.mpls_tc = mpls_tc

    def set_mpls_bos(self, bos):
        self._wc.ft_set(ofproto.OFPXMT_OFB_MPLS_BOS)
        self._flow.mpls_bos = bos

    def set_pbb_isid(self, isid):
        self._wc.ft_set(ofproto.OFPXMT_OFB_PBB_ISID)
        self._flow.pbb_isid = isid

    def set_pbb_isid_masked(self, isid, mask):
        self._wc.ft_set(ofproto.OFPXMT_OFB_PBB_ISID)
        self._wc.pbb_isid_mask = mask
        self._flow.pbb_isid = isid

    def set_tunnel_id(self, tunnel_id):
        self._wc.ft_set(ofproto.OFPXMT_OFB_TUNNEL_ID)
        self._flow.tunnel_id = tunnel_id

    def set_tunnel_id_masked(self, tunnel_id, mask):
        self._wc.ft_set(ofproto.OFPXMT_OFB_TUNNEL_ID)
        self._wc.tunnel_id_mask = mask
        self._flow.tunnel_id = tunnel_id

    def set_ipv6_exthdr(self, hdr):
        self._wc.ft_set(ofproto.OFPXMT_OFB_IPV6_EXTHDR)
        self._flow.ipv6_exthdr = hdr

    def set_ipv6_exthdr_masked(self, hdr, mask):
        self._wc.ft_set(ofproto.OFPXMT_OFB_IPV6_EXTHDR)
        self._wc.ipv6_exthdr_mask = mask
        self._flow.ipv6_exthdr = hdr


class OFPMatchField(StringifyMixin):
    _FIELDS_HEADERS = {}

    @staticmethod
    def register_field_header(headers):
        def _register_field_header(cls):
            for header in headers:
                OFPMatchField._FIELDS_HEADERS[header] = cls
            return cls
        return _register_field_header

    def __init__(self, header):
        self.header = header
        self.n_bytes = ofproto.oxm_tlv_header_extract_length(header)
        self.length = 0

    @classmethod
    def cls_to_header(cls, cls_, hasmask):
        # XXX efficiency
        inv = dict((v, k) for k, v in cls._FIELDS_HEADERS.iteritems()
                   if (((k >> 8) & 1) != 0) == hasmask)
        return inv[cls_]

    @staticmethod
    def make(header, value, mask=None):
        cls_ = OFPMatchField._FIELDS_HEADERS.get(header)
        return cls_(header, value, mask)

    @classmethod
    def parser(cls, buf, offset):
        (header,) = struct.unpack_from('!I', buf, offset)
        cls_ = OFPMatchField._FIELDS_HEADERS.get(header)
        if cls_:
            field = cls_.field_parser(header, buf, offset)
        else:
            field = OFPMatchField(header)
        field.length = (header & 0xff) + 4
        return field

    @classmethod
    def field_parser(cls, header, buf, offset):
        hasmask = (header >> 8) & 1
        mask = None
        if ofproto.oxm_tlv_header_extract_hasmask(header):
            pack_str = '!' + cls.pack_str[1:] * 2
            (value, mask) = struct.unpack_from(pack_str, buf, offset + 4)
        else:
            (value,) = struct.unpack_from(cls.pack_str, buf, offset + 4)
        return cls(header, value, mask)

    def serialize(self, buf, offset):
        if ofproto.oxm_tlv_header_extract_hasmask(self.header):
            self.put_w(buf, offset, self.value, self.mask)
        else:
            self.put(buf, offset, self.value)

    def _put_header(self, buf, offset):
        ofproto_parser.msg_pack_into('!I', buf, offset, self.header)
        self.length = 4

    def _put(self, buf, offset, value):
        ofproto_parser.msg_pack_into(self.pack_str, buf, offset, value)
        self.length += self.n_bytes

    def put_w(self, buf, offset, value, mask):
        self._put_header(buf, offset)
        self._put(buf, offset + self.length, value)
        self._put(buf, offset + self.length, mask)

    def put(self, buf, offset, value):
        self._put_header(buf, offset)
        self._put(buf, offset + self.length, value)

    def _putv6(self, buf, offset, value):
        ofproto_parser.msg_pack_into(self.pack_str, buf, offset,
                                     *value)
        self.length += self.n_bytes

    def putv6(self, buf, offset, value, mask=None):
        self._put_header(buf, offset)
        self._putv6(buf, offset + self.length, value)
        if mask and len(mask):
            self._putv6(buf, offset + self.length, mask)

    def oxm_len(self):
        return self.header & 0xff

    def to_jsondict(self):
        # remove some redundant attributes
        d = super(OFPMatchField, self).to_jsondict()
        v = d[self.__class__.__name__]
        del v['header']
        del v['length']
        del v['n_bytes']
        return d

    @classmethod
    def from_jsondict(cls, dict_):
        # just pass the dict around.
        # it will be converted by OFPMatch.__init__().
        return {cls.__name__: dict_}

    def stringify_attrs(self):
        f = super(OFPMatchField, self).stringify_attrs
        if not ofproto.oxm_tlv_header_extract_hasmask(self.header):
            # something like the following, but yield two values (k,v)
            # return itertools.ifilter(lambda k, v: k != 'mask', iter())
            def g():
                for k, v in f():
                    if k != 'mask':
                        yield (k, v)
            return g()
        else:
            return f()


@OFPMatchField.register_field_header([ofproto.OXM_OF_IN_PORT])
class MTInPort(OFPMatchField):
    pack_str = '!I'

    def __init__(self, header, value, mask=None):
        super(MTInPort, self).__init__(header)
        self.value = value


@OFPMatchField.register_field_header([ofproto.OXM_OF_METADATA,
                                      ofproto.OXM_OF_METADATA_W])
class MTMetadata(OFPMatchField):
    pack_str = '!Q'

    def __init__(self, header, value, mask=None):
        super(MTMetadata, self).__init__(header)
        self.value = value
        self.mask = mask


@OFPMatchField.register_field_header([ofproto.OXM_OF_IN_PHY_PORT])
class MTInPhyPort(OFPMatchField):
    pack_str = '!I'

    def __init__(self, header, value, mask=None):
        super(MTInPhyPort, self).__init__(header)
        self.value = value


@OFPMatchField.register_field_header([ofproto.OXM_OF_ETH_DST,
                                      ofproto.OXM_OF_ETH_DST_W])
class MTEthDst(OFPMatchField):
    pack_str = '!6s'

    def __init__(self, header, value, mask=None):
        super(MTEthDst, self).__init__(header)
        self.value = value
        self.mask = mask


@OFPMatchField.register_field_header([ofproto.OXM_OF_ETH_SRC,
                                      ofproto.OXM_OF_ETH_SRC_W])
class MTEthSrc(OFPMatchField):
    pack_str = '!6s'

    def __init__(self, header, value, mask=None):
        super(MTEthSrc, self).__init__(header)
        self.value = value
        self.mask = mask


@OFPMatchField.register_field_header([ofproto.OXM_OF_ETH_TYPE])
class MTEthType(OFPMatchField):
    pack_str = '!H'

    def __init__(self, header, value, mask=None):
        super(MTEthType, self).__init__(header)
        self.value = value


@OFPMatchField.register_field_header([ofproto.OXM_OF_VLAN_VID,
                                      ofproto.OXM_OF_VLAN_VID_W])
class MTVlanVid(OFPMatchField):
    pack_str = '!H'

    def __init__(self, header, value, mask=None):
        super(MTVlanVid, self).__init__(header)
        self.value = value
        self.mask = mask

    @classmethod
    def field_parser(cls, header, buf, offset):
        m = super(MTVlanVid, cls).field_parser(header, buf, offset)
        m.value &= ~ofproto.OFPVID_PRESENT
        return m

    def serialize(self, buf, offset):
        self.value |= ofproto.OFPVID_PRESENT
        super(MTVlanVid, self).serialize(buf, offset)


@OFPMatchField.register_field_header([ofproto.OXM_OF_VLAN_PCP])
class MTVlanPcp(OFPMatchField):
    pack_str = '!B'

    def __init__(self, header, value, mask=None):
        super(MTVlanPcp, self).__init__(header)
        self.value = value


@OFPMatchField.register_field_header([ofproto.OXM_OF_IP_DSCP])
class MTIPDscp(OFPMatchField):
    pack_str = '!B'

    def __init__(self, header, value, mask=None):
        super(MTIPDscp, self).__init__(header)
        self.value = value


@OFPMatchField.register_field_header([ofproto.OXM_OF_IP_ECN])
class MTIPECN(OFPMatchField):
    pack_str = '!B'

    def __init__(self, header, value, mask=None):
        super(MTIPECN, self).__init__(header)
        self.value = value


@OFPMatchField.register_field_header([ofproto.OXM_OF_IP_PROTO])
class MTIPProto(OFPMatchField):
    pack_str = '!B'

    def __init__(self, header, value, mask=None):
        super(MTIPProto, self).__init__(header)
        self.value = value


@OFPMatchField.register_field_header([ofproto.OXM_OF_IPV4_SRC,
                                      ofproto.OXM_OF_IPV4_SRC_W])
class MTIPV4Src(OFPMatchField):
    pack_str = '!I'

    def __init__(self, header, value, mask=None):
        super(MTIPV4Src, self).__init__(header)
        self.value = value
        self.mask = mask


@OFPMatchField.register_field_header([ofproto.OXM_OF_IPV4_DST,
                                      ofproto.OXM_OF_IPV4_DST_W])
class MTIPV4Dst(OFPMatchField):
    pack_str = '!I'

    def __init__(self, header, value, mask=None):
        super(MTIPV4Dst, self).__init__(header)
        self.value = value
        self.mask = mask


@OFPMatchField.register_field_header([ofproto.OXM_OF_TCP_SRC])
class MTTCPSrc(OFPMatchField):
    pack_str = '!H'

    def __init__(self, header, value, mask=None):
        super(MTTCPSrc, self).__init__(header)
        self.value = value


@OFPMatchField.register_field_header([ofproto.OXM_OF_TCP_DST])
class MTTCPDst(OFPMatchField):
    pack_str = '!H'

    def __init__(self, header, value, mask=None):
        super(MTTCPDst, self).__init__(header)
        self.value = value


@OFPMatchField.register_field_header([ofproto.OXM_OF_UDP_SRC])
class MTUDPSrc(OFPMatchField):
    pack_str = '!H'

    def __init__(self, header, value, mask=None):
        super(MTUDPSrc, self).__init__(header)
        self.value = value


@OFPMatchField.register_field_header([ofproto.OXM_OF_UDP_DST])
class MTUDPDst(OFPMatchField):
    pack_str = '!H'

    def __init__(self, header, value, mask=None):
        super(MTUDPDst, self).__init__(header)
        self.value = value


@OFPMatchField.register_field_header([ofproto.OXM_OF_SCTP_SRC])
class MTSCTPSrc(OFPMatchField):
    pack_str = '!H'

    def __init__(self, header, value, mask=None):
        super(MTSCTPSrc, self).__init__(header)
        self.value = value


@OFPMatchField.register_field_header([ofproto.OXM_OF_SCTP_DST])
class MTSCTPDst(OFPMatchField):
    pack_str = '!H'

    def __init__(self, header, value, mask=None):
        super(MTSCTPDst, self).__init__(header)
        self.value = value


@OFPMatchField.register_field_header([ofproto.OXM_OF_ICMPV4_TYPE])
class MTICMPV4Type(OFPMatchField):
    pack_str = '!B'

    def __init__(self, header, value, mask=None):
        super(MTICMPV4Type, self).__init__(header)
        self.value = value


@OFPMatchField.register_field_header([ofproto.OXM_OF_ICMPV4_CODE])
class MTICMPV4Code(OFPMatchField):
    pack_str = '!B'

    def __init__(self, header, value, mask=None):
        super(MTICMPV4Code, self).__init__(header)
        self.value = value


@OFPMatchField.register_field_header([ofproto.OXM_OF_ARP_OP])
class MTArpOp(OFPMatchField):
    pack_str = '!H'

    def __init__(self, header, value, mask=None):
        super(MTArpOp, self).__init__(header)
        self.value = value


@OFPMatchField.register_field_header([ofproto.OXM_OF_ARP_SPA,
                                      ofproto.OXM_OF_ARP_SPA_W])
class MTArpSpa(OFPMatchField):
    pack_str = '!I'

    def __init__(self, header, value, mask=None):
        super(MTArpSpa, self).__init__(header)
        self.value = value
        self.mask = mask


@OFPMatchField.register_field_header([ofproto.OXM_OF_ARP_TPA,
                                      ofproto.OXM_OF_ARP_TPA_W])
class MTArpTpa(OFPMatchField):
    pack_str = '!I'

    def __init__(self, header, value, mask=None):
        super(MTArpTpa, self).__init__(header)
        self.value = value
        self.mask = mask


@OFPMatchField.register_field_header([ofproto.OXM_OF_ARP_SHA,
                                      ofproto.OXM_OF_ARP_SHA_W])
class MTArpSha(OFPMatchField):
    pack_str = '!6s'

    def __init__(self, header, value, mask=None):
        super(MTArpSha, self).__init__(header)
        self.value = value
        self.mask = mask


@OFPMatchField.register_field_header([ofproto.OXM_OF_ARP_THA,
                                      ofproto.OXM_OF_ARP_THA_W])
class MTArpTha(OFPMatchField):
    pack_str = '!6s'

    def __init__(self, header, value, mask=None):
        super(MTArpTha, self).__init__(header)
        self.value = value
        self.mask = mask


class MTIPv6(StringifyMixin):
    @classmethod
    def field_parser(cls, header, buf, offset):
        if ofproto.oxm_tlv_header_extract_hasmask(header):
            pack_str = '!' + cls.pack_str[1:] * 2
            value = struct.unpack_from(pack_str, buf, offset + 4)
            return cls(header, list(value[:8]), list(value[8:]))
        else:
            value = struct.unpack_from(cls.pack_str, buf, offset + 4)
            return cls(header, list(value))

    def serialize(self, buf, offset):
        self.putv6(buf, offset, self.value, self.mask)


@OFPMatchField.register_field_header([ofproto.OXM_OF_IPV6_SRC,
                                      ofproto.OXM_OF_IPV6_SRC_W])
class MTIPv6Src(MTIPv6, OFPMatchField):
    pack_str = '!8H'

    def __init__(self, header, value, mask=None):
        super(MTIPv6Src, self).__init__(header)
        self.value = value
        self.mask = mask


@OFPMatchField.register_field_header([ofproto.OXM_OF_IPV6_DST,
                                      ofproto.OXM_OF_IPV6_DST_W])
class MTIPv6Dst(MTIPv6, OFPMatchField):
    pack_str = '!8H'

    def __init__(self, header, value, mask=None):
        super(MTIPv6Dst, self).__init__(header)
        self.value = value
        self.mask = mask


@OFPMatchField.register_field_header([ofproto.OXM_OF_IPV6_FLABEL,
                                      ofproto.OXM_OF_IPV6_FLABEL_W])
class MTIPv6Flabel(OFPMatchField):
    pack_str = '!I'

    def __init__(self, header, value, mask=None):
        super(MTIPv6Flabel, self).__init__(header)
        self.value = value
        self.mask = mask


@OFPMatchField.register_field_header([ofproto.OXM_OF_MPLS_LABEL])
class MTMplsLabel(OFPMatchField):
    pack_str = '!I'

    def __init__(self, header, value, mask=None):
        super(MTMplsLabel, self).__init__(header)
        self.value = value


@OFPMatchField.register_field_header([ofproto.OXM_OF_ICMPV6_TYPE])
class MTICMPV6Type(OFPMatchField):
    pack_str = '!B'

    def __init__(self, header, value, mask=None):
        super(MTICMPV6Type, self).__init__(header)
        self.value = value


@OFPMatchField.register_field_header([ofproto.OXM_OF_ICMPV6_CODE])
class MTICMPV6Code(OFPMatchField):
    pack_str = '!B'

    def __init__(self, header, value, mask=None):
        super(MTICMPV6Code, self).__init__(header)
        self.value = value


@OFPMatchField.register_field_header([ofproto.OXM_OF_IPV6_ND_TARGET])
class MTIPv6NdTarget(MTIPv6, OFPMatchField):
    pack_str = '!8H'

    def __init__(self, header, value, mask=None):
        super(MTIPv6NdTarget, self).__init__(header)
        self.value = value

    def serialize(self, buf, offset):
        self.putv6(buf, offset, self.value)


@OFPMatchField.register_field_header([ofproto.OXM_OF_IPV6_ND_SLL])
class MTIPv6NdSll(OFPMatchField):
    pack_str = '!6s'

    def __init__(self, header, value, mask=None):
        super(MTIPv6NdSll, self).__init__(header)
        self.value = value


@OFPMatchField.register_field_header([ofproto.OXM_OF_IPV6_ND_TLL])
class MTIPv6NdTll(OFPMatchField):
    pack_str = '!6s'

    def __init__(self, header, value, mask=None):
        super(MTIPv6NdTll, self).__init__(header)
        self.value = value


@OFPMatchField.register_field_header([ofproto.OXM_OF_MPLS_TC])
class MTMplsTc(OFPMatchField):
    pack_str = '!B'

    def __init__(self, header, value, mask=None):
        super(MTMplsTc, self).__init__(header)
        self.value = value


@OFPMatchField.register_field_header([ofproto.OXM_OF_MPLS_BOS])
class MTMplsBos(OFPMatchField):
    pack_str = '!B'

    def __init__(self, header, value, mask=None):
        super(MTMplsBos, self).__init__(header)
        self.value = value


@OFPMatchField.register_field_header([ofproto.OXM_OF_PBB_ISID,
                                      ofproto.OXM_OF_PBB_ISID_W])
class MTPbbIsid(OFPMatchField):
    pack_str = '!3B'

    def __init__(self, header, value, mask=None):
        super(MTPbbIsid, self).__init__(header)
        self.value = value
        self.mask = mask

    @classmethod
    def field_parser(cls, header, buf, offset):
        hasmask = (header >> 8) & 1
        mask = None
        if ofproto.oxm_tlv_header_extract_hasmask(header):
            pack_str = '!' + cls.pack_str[1:] * 2
            (v1, v2, v3, m1, m2, m3) = struct.unpack_from(pack_str, buf,
                                                          offset + 4)
            value = v1 << 16 | v2 << 8 | v3
            mask = m1 << 16 | m2 << 8 | m3
        else:
            (v1, v2, v3,) = struct.unpack_from(cls.pack_str, buf, offset + 4)
            value = v1 << 16 | v2 << 8 | v3
        return cls(header, value, mask)

    def _put(self, buf, offset, value):
        ofproto_parser.msg_pack_into(self.pack_str, buf, offset,
                                     (value >> 16) & 0xff,
                                     (value >> 8) & 0xff,
                                     (value >> 0) & 0xff)
        self.length += self.n_bytes


@OFPMatchField.register_field_header([ofproto.OXM_OF_TUNNEL_ID,
                                      ofproto.OXM_OF_TUNNEL_ID_W])
class MTTunnelId(OFPMatchField):
    pack_str = '!Q'

    def __init__(self, header, value, mask=None):
        super(MTTunnelId, self).__init__(header)
        self.value = value
        self.mask = mask


@OFPMatchField.register_field_header([ofproto.OXM_OF_IPV6_EXTHDR,
                                      ofproto.OXM_OF_IPV6_EXTHDR_W])
class MTIPv6ExtHdr(OFPMatchField):
    pack_str = '!H'

    def __init__(self, header, value, mask=None):
        super(MTIPv6ExtHdr, self).__init__(header)
        self.value = value
        self.mask = mask


@_register_parser
@_set_msg_type(ofproto.OFPT_PACKET_IN)
class OFPPacketIn(MsgBase):
    """
    Packet-In message

    The switch sends the packet that received to the controller by this
    message.

    ============= =========================================================
    Attribute     Description
    ============= =========================================================
    buffer_id     ID assigned by datapath
    total_len     Full length of frame
    reason        Reason packet is being sent.

                  | OFPR_NO_MATCH
                  | OFPR_ACTION
                  | OFPR_INVALID_TTL
    table_id      ID of the table that was looked up
    cookie        Cookie of the flow entry that was looked up
    match         Instance of ``OFPMatch``
    data          Ethernet frame
    ============= =========================================================

    Example::

        @set_ev_cls(ofp_event.EventOFPPacketIn, MAIN_DISPATCHER)
        def packet_in_handler(self, ev):
            msg = ev.msg
            ofp = dp.ofproto

            if msg.reason == ofp.OFPR_NO_MATCH:
                reason = 'NO MATCH'
            elif msg.reason == ofp.OFPR_ACTION:
                reason = 'ACTION'
            elif msg.reason == ofp.OFPR_INVALID_TTL:
                reason = 'INVALID TTL'
            else:
                reason = 'unknown'

            self.logger.debug('OFPPacketIn received: '
                              'buffer_id=%x total_len=%d reason=%s '
                              'table_id=%d cookie=%d match=%s data=%s',
                              msg.buffer_id, msg.total_len, reason,
                              msg.table_id, msg.cookie, msg.match,
                              utils.hex_array(msg.data))
    """
    def __init__(self, datapath, buffer_id=None, total_len=None, reason=None,
                 table_id=None, cookie=None, match=None, data=None):
        super(OFPPacketIn, self).__init__(datapath)
        self.buffer_id = buffer_id
        self.total_len = total_len
        self.reason = reason
        self.table_id = table_id
        self.cookie = cookie
        self.match = match
        self.data = data

    @classmethod
    def parser(cls, datapath, version, msg_type, msg_len, xid, buf):
        msg = super(OFPPacketIn, cls).parser(datapath, version, msg_type,
                                             msg_len, xid, buf)
        (msg.buffer_id, msg.total_len, msg.reason,
         msg.table_id, msg.cookie) = struct.unpack_from(
            ofproto.OFP_PACKET_IN_PACK_STR,
            msg.buf, ofproto.OFP_HEADER_SIZE)

        msg.match = OFPMatch.parser(msg.buf, ofproto.OFP_PACKET_IN_SIZE -
                                    ofproto.OFP_MATCH_SIZE)

        match_len = utils.round_up(msg.match.length, 8)
        msg.data = msg.buf[(ofproto.OFP_PACKET_IN_SIZE -
                            ofproto.OFP_MATCH_SIZE + match_len + 2):]

        if msg.total_len < len(msg.data):
            # discard padding for 8-byte alignment of OFP packet
            msg.data = msg.data[:msg.total_len]

        return msg


@_register_parser
@_set_msg_type(ofproto.OFPT_FLOW_REMOVED)
class OFPFlowRemoved(MsgBase):
    """
    Flow removed message

    When flow entries time out or are deleted, the switch notifies controller
    with this message.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    cookie           Opaque controller-issued identifier
    priority         Priority level of flow entry
    reason           One of the following values.

                     | OFPRR_IDLE_TIMEOUT
                     | OFPRR_HARD_TIMEOUT
                     | OFPRR_DELETE
                     | OFPRR_GROUP_DELETE
    table_id         ID of the table
    duration_sec     Time flow was alive in seconds
    duration_nsec    Time flow was alive in nanoseconds beyond duration_sec
    idle_timeout     Idle timeout from original flow mod
    hard_timeout     Hard timeout from original flow mod
    packet_count     Number of packets that was associated with the flow
    byte_count       Number of bytes that was associated with the flow
    match            Instance of ``OFPMatch``
    ================ ======================================================

    Example::

        @set_ev_cls(ofp_event.EventOFPFlowRemoved, MAIN_DISPATCHER)
        def flow_removed_handler(self, ev):
            msg = ev.msg
            dp = msg.datapath
            ofp = dp.ofproto

            if msg.reason == ofp.OFPRR_IDLE_TIMEOUT:
                reason = 'IDLE TIMEOUT'
            elif msg.reason == ofp.OFPRR_HARD_TIMEOUT:
                reason = 'HARD TIMEOUT'
            elif msg.reason == ofp.OFPRR_DELETE:
                reason = 'DELETE'
            elif msg.reason == ofp.OFPRR_GROUP_DELETE:
                reason = 'GROUP DELETE'
            else:
                reason = 'unknown'

            self.logger.debug('OFPFlowRemoved received: '
                              'cookie=%d priority=%d reason=%s table_id=%d '
                              'duration_sec=%d duration_nsec=%d '
                              'idle_timeout=%d hard_timeout=%d '
                              'packet_count=%d byte_count=%d match.fields=%s',
                              msg.cookie, msg.priority, reason, msg.table_id,
                              msg.duration_sec, msg.duration_nsec,
                              msg.idle_timeout, msg.hard_timeout,
                              msg.packet_count, msg.byte_count, msg.match)
    """
    def __init__(self, datapath, cookie=None, priority=None, reason=None,
                 table_id=None, duration_sec=None, duration_nsec=None,
                 idle_timeout=None, hard_timeout=None, packet_count=None,
                 byte_count=None, match=None):
        super(OFPFlowRemoved, self).__init__(datapath)
        self.cookie = cookie
        self.priority = priority
        self.reason = reason
        self.table_id = table_id
        self.duration_sec = duration_sec
        self.duration_nsec = duration_nsec
        self.idle_timeout = idle_timeout
        self.hard_timeout = hard_timeout
        self.packet_count = packet_count
        self.byte_count = byte_count
        self.match = match

    @classmethod
    def parser(cls, datapath, version, msg_type, msg_len, xid, buf):
        msg = super(OFPFlowRemoved, cls).parser(datapath, version, msg_type,
                                                msg_len, xid, buf)

        (msg.cookie, msg.priority, msg.reason,
         msg.table_id, msg.duration_sec, msg.duration_nsec,
         msg.idle_timeout, msg.hard_timeout, msg.packet_count,
         msg.byte_count) = struct.unpack_from(
            ofproto.OFP_FLOW_REMOVED_PACK_STR0,
            msg.buf, ofproto.OFP_HEADER_SIZE)

        offset = (ofproto.OFP_FLOW_REMOVED_SIZE -
                  ofproto.OFP_MATCH_SIZE)

        msg.match = OFPMatch.parser(msg.buf, offset)

        return msg


class OFPPort(ofproto_parser.namedtuple('OFPPort', (
        'port_no', 'hw_addr', 'name', 'config', 'state', 'curr',
        'advertised', 'supported', 'peer', 'curr_speed', 'max_speed'))):

    _TYPE = {
        'ascii': [
            'hw_addr',
        ],
        'utf-8': [
            # OF spec is unclear about the encoding of name.
            # we assumes UTF-8, which is used by OVS.
            'name',
        ]
    }

    @classmethod
    def parser(cls, buf, offset):
        port = struct.unpack_from(ofproto.OFP_PORT_PACK_STR, buf, offset)
        port = list(port)
        i = cls._fields.index('hw_addr')
        port[i] = addrconv.mac.bin_to_text(port[i])
        i = cls._fields.index('name')
        port[i] = port[i].rstrip('\0')
        ofpport = cls(*port)
        ofpport.length = ofproto.OFP_PORT_SIZE
        return ofpport


@_register_parser
@_set_msg_type(ofproto.OFPT_PORT_STATUS)
class OFPPortStatus(MsgBase):
    """
    Port status message

    The switch notifies controller of change of ports.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    reason           One of the following values.

                     | OFPPR_ADD
                     | OFPPR_DELETE
                     | OFPPR_MODIFY
    desc             instance of ``OFPPort``
    ================ ======================================================

    Example::

        @set_ev_cls(ofp_event.EventOFPPortStatus, MAIN_DISPATCHER)
        def port_status_handler(self, ev):
            msg = ev.msg
            dp = msg.datapath
            ofp = dp.ofproto

            if msg.reason == ofp.OFPPR_ADD:
                reason = 'ADD'
            elif msg.reason == ofp.OFPPR_DELETE:
                reason = 'DELETE'
            elif msg.reason == ofp.OFPPR_MODIFY:
                reason = 'MODIFY'
            else:
                reason = 'unknown'

            self.logger.debug('OFPPortStatus received: reason=%s desc=%s',
                              reason, msg.desc)
    """
    def __init__(self, datapath, reason=None, desc=None):
        super(OFPPortStatus, self).__init__(datapath)
        self.reason = reason
        self.desc = desc

    @classmethod
    def parser(cls, datapath, version, msg_type, msg_len, xid, buf):
        msg = super(OFPPortStatus, cls).parser(datapath, version, msg_type,
                                               msg_len, xid, buf)
        msg.reason = struct.unpack_from(
            ofproto.OFP_PORT_STATUS_PACK_STR, msg.buf,
            ofproto.OFP_HEADER_SIZE)[0]
        msg.desc = OFPPort.parser(msg.buf,
                                  ofproto.OFP_PORT_STATUS_DESC_OFFSET)
        return msg


@_set_msg_type(ofproto.OFPT_PACKET_OUT)
class OFPPacketOut(MsgBase):
    """
    Packet-Out message

    The controller uses this message to send a packet out throught the
    switch.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    buffer_id        ID assigned by datapath (OFP_NO_BUFFER if none)
    in_port          Packet's input port or ``OFPP_CONTROLLER``
    actions          list of OpenFlow action class
    data             Packet data
    ================ ======================================================

    Example::

        def send_packet_out(self, datapath, buffer_id, in_port):
            ofp = datapath.ofproto
            ofp_parser = datapath.ofproto_parser

            actions = [ofp_parser.OFPActionOutput(ofp.OFPP_FLOOD, 0)]
            req = ofp_parser.OFPPacketOut(datapath, buffer_id,
                                          in_port, actions)
            datapath.send_msg(req)
    """
    def __init__(self, datapath, buffer_id=None, in_port=None, actions=None,
                 data=None, actions_len=None):
        assert in_port is not None

        super(OFPPacketOut, self).__init__(datapath)
        self.buffer_id = buffer_id
        self.in_port = in_port
        self.actions_len = 0
        self.actions = actions
        self.data = data

    def _serialize_body(self):
        self.actions_len = 0
        offset = ofproto.OFP_PACKET_OUT_SIZE
        for a in self.actions:
            a.serialize(self.buf, offset)
            offset += a.len
            self.actions_len += a.len

        if self.data is not None:
            assert self.buffer_id == 0xffffffff
            self.buf += self.data

        msg_pack_into(ofproto.OFP_PACKET_OUT_PACK_STR,
                      self.buf, ofproto.OFP_HEADER_SIZE,
                      self.buffer_id, self.in_port, self.actions_len)


@_set_msg_type(ofproto.OFPT_FLOW_MOD)
class OFPFlowMod(MsgBase):
    """
    Modify Flow entry message

    The controller sends this message to modify the flow table.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    cookie           Opaque controller-issued identifier
    cookie_mask      Mask used to restrict the cookie bits that must match
                     when the command is ``OPFFC_MODIFY*`` or
                     ``OFPFC_DELETE*``
    table_id         ID of the table to put the flow in
    command          One of the following values.

                     | OFPFC_ADD
                     | OFPFC_MODIFY
                     | OFPFC_MODIFY_STRICT
                     | OFPFC_DELETE
                     | OFPFC_DELETE_STRICT
    idle_timeout     Idle time before discarding (seconds)
    hard_timeout     Max time before discarding (seconds)
    priority         Priority level of flow entry
    buffer_id        Buffered packet to apply to (or OFP_NO_BUFFER)
    out_port         For ``OFPFC_DELETE*`` commands, require matching
                     entries to include this as an output port
    out_group        For ``OFPFC_DELETE*`` commands, require matching
                     entries to include this as an output group
    flags            Bitmap of the following flags.

                     | OFPFF_SEND_FLOW_REM
                     | OFPFF_CHECK_OVERLAP
                     | OFPFF_RESET_COUNTS
                     | OFPFF_NO_PKT_COUNTS
                     | OFPFF_NO_BYT_COUNTS
    match            Instance of ``OFPMatch``
    instructions     list of ``OFPInstruction*`` instance
    ================ ======================================================

    Example::

        def send_flow_mod(self, datapath):
            ofp = datapath.ofproto
            ofp_parser = datapath.ofproto_parser

            cookie = cookie_mask = 0
            table_id = 0
            idle_timeout = hard_timeout = 0
            priority = 32768
            buffer_id = ofp.OFP_NO_BUFFER
            match = ofp_parser.OFPMatch(in_port=1, eth_dst='ff:ff:ff:ff:ff:ff')
            actions = [ofp_parser.OFPActionOutput(ofp.OFPP_NORMAL, 0)]
            inst = [ofp_parser.OFPInstructionActions(ofp.OFPIT_APPLY_ACTIONS,
                                                     actions)]
            req = ofp_parser.OFPFlowMod(datapath, cookie, cookie_mask,
                                        table_id, ofp.OFPFC_ADD,
                                        idle_timeout, hard_timeout,
                                        priority, buffer_id,
                                        ofp.OFPP_ANY, ofp.OFPG_ANY,
                                        ofp.OFPFF_SEND_FLOW_REM,
                                        match, inst)
            datapath.send_msg(req)
    """
    def __init__(self, datapath, cookie=0, cookie_mask=0, table_id=0,
                 command=ofproto.OFPFC_ADD,
                 idle_timeout=0, hard_timeout=0,
                 priority=ofproto.OFP_DEFAULT_PRIORITY,
                 buffer_id=ofproto.OFP_NO_BUFFER,
                 out_port=0, out_group=0, flags=0,
                 match=None,
                 instructions=[]):
        super(OFPFlowMod, self).__init__(datapath)
        self.cookie = cookie
        self.cookie_mask = cookie_mask
        self.table_id = table_id
        self.command = command
        self.idle_timeout = idle_timeout
        self.hard_timeout = hard_timeout
        self.priority = priority
        self.buffer_id = buffer_id
        self.out_port = out_port
        self.out_group = out_group
        self.flags = flags
        if match is None:
            match = OFPMatch()
        assert isinstance(match, OFPMatch)
        self.match = match
        for i in instructions:
            assert isinstance(i, OFPInstruction)
        self.instructions = instructions

    def _serialize_body(self):
        msg_pack_into(ofproto.OFP_FLOW_MOD_PACK_STR0, self.buf,
                      ofproto.OFP_HEADER_SIZE,
                      self.cookie, self.cookie_mask, self.table_id,
                      self.command, self.idle_timeout, self.hard_timeout,
                      self.priority, self.buffer_id, self.out_port,
                      self.out_group, self.flags)

        offset = (ofproto.OFP_FLOW_MOD_SIZE -
                  ofproto.OFP_MATCH_SIZE)

        match_len = self.match.serialize(self.buf, offset)
        offset += match_len

        for inst in self.instructions:
            inst.serialize(self.buf, offset)
            offset += inst.len


class OFPInstruction(StringifyMixin):
    _INSTRUCTION_TYPES = {}

    @staticmethod
    def register_instruction_type(types):
        def _register_instruction_type(cls):
            for type_ in types:
                OFPInstruction._INSTRUCTION_TYPES[type_] = cls
            return cls
        return _register_instruction_type

    @classmethod
    def parser(cls, buf, offset):
        (type_, len_) = struct.unpack_from('!HH', buf, offset)
        cls_ = cls._INSTRUCTION_TYPES.get(type_)
        return cls_.parser(buf, offset)


@OFPInstruction.register_instruction_type([ofproto.OFPIT_GOTO_TABLE])
class OFPInstructionGotoTable(OFPInstruction):
    """
    Goto table instruction

    This instruction indicates the next table in the processing pipeline.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    table_id         Next table
    ================ ======================================================
    """
    def __init__(self, table_id, type_=None, len_=None):
        super(OFPInstructionGotoTable, self).__init__()
        self.type = ofproto.OFPIT_GOTO_TABLE
        self.len = ofproto.OFP_INSTRUCTION_GOTO_TABLE_SIZE
        self.table_id = table_id

    @classmethod
    def parser(cls, buf, offset):
        (type_, len_, table_id) = struct.unpack_from(
            ofproto.OFP_INSTRUCTION_GOTO_TABLE_PACK_STR,
            buf, offset)
        return cls(table_id)

    def serialize(self, buf, offset):
        msg_pack_into(ofproto.OFP_INSTRUCTION_GOTO_TABLE_PACK_STR,
                      buf, offset, self.type, self.len, self.table_id)


@OFPInstruction.register_instruction_type([ofproto.OFPIT_WRITE_METADATA])
class OFPInstructionWriteMetadata(OFPInstruction):
    """
    Write metadata instruction

    This instruction writes the masked metadata value into the metadata field.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    metadata         Metadata value to write
    metadata_mask    Metadata write bitmask
    ================ ======================================================
    """
    def __init__(self, metadata, metadata_mask, type_=None, len_=None):
        super(OFPInstructionWriteMetadata, self).__init__()
        self.type = ofproto.OFPIT_WRITE_METADATA
        self.len = ofproto.OFP_INSTRUCTION_WRITE_METADATA_SIZE
        self.metadata = metadata
        self.metadata_mask = metadata_mask

    @classmethod
    def parser(cls, buf, offset):
        (type_, len_, metadata, metadata_mask) = struct.unpack_from(
            ofproto.OFP_INSTRUCTION_WRITE_METADATA_PACK_STR,
            buf, offset)
        return cls(metadata, metadata_mask)

    def serialize(self, buf, offset):
        msg_pack_into(ofproto.OFP_INSTRUCTION_WRITE_METADATA_PACK_STR,
                      buf, offset, self.type, self.len, self.metadata,
                      self.metadata_mask)


@OFPInstruction.register_instruction_type([ofproto.OFPIT_WRITE_ACTIONS,
                                           ofproto.OFPIT_APPLY_ACTIONS,
                                           ofproto.OFPIT_CLEAR_ACTIONS])
class OFPInstructionActions(OFPInstruction):
    """
    Actions instruction

    This instruction writes/applies/clears the actions.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    type             One of following values.

                     | OFPIT_WRITE_ACTIONS
                     | OFPIT_APPLY_ACTIONS
                     | OFPIT_CLEAR_ACTIONS
    actions          list of OpenFlow action class
    ================ ======================================================

    ``type`` attribute corresponds to ``type_`` parameter of __init__.
    """
    def __init__(self, type_, actions=None, len_=None):
        super(OFPInstructionActions, self).__init__()
        self.type = type_
        for a in actions:
            assert isinstance(a, OFPAction)
        self.actions = actions

    @classmethod
    def parser(cls, buf, offset):
        (type_, len_) = struct.unpack_from(
            ofproto.OFP_INSTRUCTION_ACTIONS_PACK_STR,
            buf, offset)

        offset += ofproto.OFP_INSTRUCTION_ACTIONS_SIZE
        actions = []
        actions_len = len_ - ofproto.OFP_INSTRUCTION_ACTIONS_SIZE
        while actions_len > 0:
            a = OFPAction.parser(buf, offset)
            actions.append(a)
            actions_len -= a.len
            offset += a.len

        inst = cls(type_, actions)
        inst.len = len_
        return inst

    def serialize(self, buf, offset):
        action_offset = offset + ofproto.OFP_INSTRUCTION_ACTIONS_SIZE
        if self.actions:
            for a in self.actions:
                a.serialize(buf, action_offset)
                action_offset += a.len

        self.len = action_offset - offset
        pad_len = utils.round_up(self.len, 8) - self.len
        ofproto_parser.msg_pack_into("%dx" % pad_len, buf, action_offset)
        self.len += pad_len

        msg_pack_into(ofproto.OFP_INSTRUCTION_ACTIONS_PACK_STR,
                      buf, offset, self.type, self.len)


@OFPInstruction.register_instruction_type([ofproto.OFPIT_METER])
class OFPInstructionMeter(OFPInstruction):
    """
    Meter instruction

    This instruction applies the meter.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    meter_id         Meter instance
    ================ ======================================================
    """

    def __init__(self, meter_id=1, type_=None, len_=None):
        super(OFPInstructionMeter, self).__init__()
        self.type = ofproto.OFPIT_METER
        self.len = ofproto.OFP_INSTRUCTION_METER_SIZE
        self.meter_id = meter_id

    @classmethod
    def parser(cls, buf, offset):
        (type_, len_, meter_id) = struct.unpack_from(
            ofproto.OFP_INSTRUCTION_METER_PACK_STR,
            buf, offset)
        return cls(meter_id)

    def serialize(self, buf, offset):
        msg_pack_into(ofproto.OFP_INSTRUCTION_METER_PACK_STR,
                      buf, offset, self.type, self.len, self.meter_id)


class OFPActionHeader(StringifyMixin):
    def __init__(self, type_, len_):
        self.type = type_
        self.len = len_

    def serialize(self, buf, offset):
        msg_pack_into(ofproto.OFP_ACTION_HEADER_PACK_STR,
                      buf, offset, self.type, self.len)


class OFPAction(OFPActionHeader):
    _ACTION_TYPES = {}

    @staticmethod
    def register_action_type(type_, len_):
        def _register_action_type(cls):
            cls.cls_action_type = type_
            cls.cls_action_len = len_
            OFPAction._ACTION_TYPES[cls.cls_action_type] = cls
            return cls
        return _register_action_type

    def __init__(self):
        cls = self.__class__
        super(OFPAction, self).__init__(cls.cls_action_type,
                                        cls.cls_action_len)

    @classmethod
    def parser(cls, buf, offset):
        type_, len_ = struct.unpack_from(
            ofproto.OFP_ACTION_HEADER_PACK_STR, buf, offset)
        cls_ = cls._ACTION_TYPES.get(type_)
        assert cls_ is not None
        return cls_.parser(buf, offset)


@OFPAction.register_action_type(ofproto.OFPAT_OUTPUT,
                                ofproto.OFP_ACTION_OUTPUT_SIZE)
class OFPActionOutput(OFPAction):
    """
    Output action

    This action indicates output a packet to the switch port.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    port             Output port
    max_len          Max length to send to controller
    ================ ======================================================
    """
    def __init__(self, port, max_len=ofproto.OFPCML_MAX,
                 type_=None, len_=None):
        super(OFPActionOutput, self).__init__()
        self.port = port
        self.max_len = max_len

    @classmethod
    def parser(cls, buf, offset):
        type_, len_, port, max_len = struct.unpack_from(
            ofproto.OFP_ACTION_OUTPUT_PACK_STR, buf, offset)
        return cls(port, max_len)

    def serialize(self, buf, offset):
        msg_pack_into(ofproto.OFP_ACTION_OUTPUT_PACK_STR, buf,
                      offset, self.type, self.len, self.port, self.max_len)


@OFPAction.register_action_type(ofproto.OFPAT_GROUP,
                                ofproto.OFP_ACTION_GROUP_SIZE)
class OFPActionGroup(OFPAction):
    """
    Group action

    This action indicates the group used to process the packet.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    group_id         Group identifier
    ================ ======================================================
    """
    def __init__(self, group_id=0, type_=None, len_=None):
        super(OFPActionGroup, self).__init__()
        self.group_id = group_id

    @classmethod
    def parser(cls, buf, offset):
        (type_, len_, group_id) = struct.unpack_from(
            ofproto.OFP_ACTION_GROUP_PACK_STR, buf, offset)
        return cls(group_id)

    def serialize(self, buf, offset):
        msg_pack_into(ofproto.OFP_ACTION_GROUP_PACK_STR, buf,
                      offset, self.type, self.len, self.group_id)


@OFPAction.register_action_type(ofproto.OFPAT_SET_QUEUE,
                                ofproto.OFP_ACTION_SET_QUEUE_SIZE)
class OFPActionSetQueue(OFPAction):
    """
    Set queue action

    This action sets the queue id that will be used to map a flow to an
    already-configured queue on a port.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    queue_id         Queue ID for the packets
    ================ ======================================================
    """
    def __init__(self, queue_id, type_=None, len_=None):
        super(OFPActionSetQueue, self).__init__()
        self.queue_id = queue_id

    @classmethod
    def parser(cls, buf, offset):
        (type_, len_, queue_id) = struct.unpack_from(
            ofproto.OFP_ACTION_SET_QUEUE_PACK_STR, buf, offset)
        return cls(queue_id)

    def serialize(self, buf, offset):
        msg_pack_into(ofproto.OFP_ACTION_SET_QUEUE_PACK_STR, buf,
                      offset, self.type, self.len, self.queue_id)


@OFPAction.register_action_type(ofproto.OFPAT_SET_MPLS_TTL,
                                ofproto.OFP_ACTION_MPLS_TTL_SIZE)
class OFPActionSetMplsTtl(OFPAction):
    """
    Set MPLS TTL action

    This action sets the MPLS TTL.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    mpls_ttl         MPLS TTL
    ================ ======================================================
    """
    def __init__(self, mpls_ttl, type_=None, len_=None):
        super(OFPActionSetMplsTtl, self).__init__()
        self.mpls_ttl = mpls_ttl

    @classmethod
    def parser(cls, buf, offset):
        (type_, len_, mpls_ttl) = struct.unpack_from(
            ofproto.OFP_ACTION_MPLS_TTL_PACK_STR, buf, offset)
        return cls(mpls_ttl)

    def serialize(self, buf, offset):
        msg_pack_into(ofproto.OFP_ACTION_MPLS_TTL_PACK_STR, buf,
                      offset, self.type, self.len, self.mpls_ttl)


@OFPAction.register_action_type(ofproto.OFPAT_DEC_MPLS_TTL,
                                ofproto.OFP_ACTION_HEADER_SIZE)
class OFPActionDecMplsTtl(OFPAction):
    """
    Decrement MPLS TTL action

    This action decrements the MPLS TTL.
    """
    def __init__(self, type_=None, len_=None):
        super(OFPActionDecMplsTtl, self).__init__()

    @classmethod
    def parser(cls, buf, offset):
        (type_, len_) = struct.unpack_from(
            ofproto.OFP_ACTION_HEADER_PACK_STR, buf, offset)
        return cls()


@OFPAction.register_action_type(ofproto.OFPAT_SET_NW_TTL,
                                ofproto.OFP_ACTION_NW_TTL_SIZE)
class OFPActionSetNwTtl(OFPAction):
    """
    Set IP TTL action

    This action sets the IP TTL.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    nw_ttl           IP TTL
    ================ ======================================================
    """
    def __init__(self, nw_ttl, type_=None, len_=None):
        super(OFPActionSetNwTtl, self).__init__()
        self.nw_ttl = nw_ttl

    @classmethod
    def parser(cls, buf, offset):
        (type_, len_, nw_ttl) = struct.unpack_from(
            ofproto.OFP_ACTION_NW_TTL_PACK_STR, buf, offset)
        return cls(nw_ttl)

    def serialize(self, buf, offset):
        msg_pack_into(ofproto.OFP_ACTION_NW_TTL_PACK_STR, buf, offset,
                      self.type, self.len, self.nw_ttl)


@OFPAction.register_action_type(ofproto.OFPAT_DEC_NW_TTL,
                                ofproto.OFP_ACTION_HEADER_SIZE)
class OFPActionDecNwTtl(OFPAction):
    """
    Decrement IP TTL action

    This action decrements the IP TTL.
    """
    def __init__(self, type_=None, len_=None):
        super(OFPActionDecNwTtl, self).__init__()

    @classmethod
    def parser(cls, buf, offset):
        (type_, len_) = struct.unpack_from(
            ofproto.OFP_ACTION_HEADER_PACK_STR, buf, offset)
        return cls()


@OFPAction.register_action_type(ofproto.OFPAT_COPY_TTL_OUT,
                                ofproto.OFP_ACTION_HEADER_SIZE)
class OFPActionCopyTtlOut(OFPAction):
    """
    Copy TTL Out action

    This action copies the TTL from the next-to-outermost header with TTL to
    the outermost header with TTL.
    """
    def __init__(self, type_=None, len_=None):
        super(OFPActionCopyTtlOut, self).__init__()

    @classmethod
    def parser(cls, buf, offset):
        (type_, len_) = struct.unpack_from(
            ofproto.OFP_ACTION_HEADER_PACK_STR, buf, offset)
        return cls()


@OFPAction.register_action_type(ofproto.OFPAT_COPY_TTL_IN,
                                ofproto.OFP_ACTION_HEADER_SIZE)
class OFPActionCopyTtlIn(OFPAction):
    """
    Copy TTL In action

    This action copies the TTL from the outermost header with TTL to the
    next-to-outermost header with TTL.
    """
    def __init__(self, type_=None, len_=None):
        super(OFPActionCopyTtlIn, self).__init__()

    @classmethod
    def parser(cls, buf, offset):
        (type_, len_) = struct.unpack_from(
            ofproto.OFP_ACTION_HEADER_PACK_STR, buf, offset)
        return cls()


@OFPAction.register_action_type(ofproto.OFPAT_PUSH_VLAN,
                                ofproto.OFP_ACTION_PUSH_SIZE)
class OFPActionPushVlan(OFPAction):
    """
    Push VLAN action

    This action pushes a new VLAN tag to the packet.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    ethertype        Ether type.  The default is 802.1Q. (0x8100)
    ================ ======================================================
    """
    def __init__(self, ethertype=ether.ETH_TYPE_8021Q, type_=None, len_=None):
        super(OFPActionPushVlan, self).__init__()
        self.ethertype = ethertype

    @classmethod
    def parser(cls, buf, offset):
        (type_, len_, ethertype) = struct.unpack_from(
            ofproto.OFP_ACTION_PUSH_PACK_STR, buf, offset)
        return cls(ethertype)

    def serialize(self, buf, offset):
        msg_pack_into(ofproto.OFP_ACTION_PUSH_PACK_STR, buf, offset,
                      self.type, self.len, self.ethertype)


@OFPAction.register_action_type(ofproto.OFPAT_PUSH_MPLS,
                                ofproto.OFP_ACTION_PUSH_SIZE)
class OFPActionPushMpls(OFPAction):
    """
    Push MPLS action

    This action pushes a new MPLS header to the packet.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    ethertype        Ether type
    ================ ======================================================
    """
    def __init__(self, ethertype=ether.ETH_TYPE_MPLS, type_=None, len_=None):
        super(OFPActionPushMpls, self).__init__()
        self.ethertype = ethertype

    @classmethod
    def parser(cls, buf, offset):
        (type_, len_, ethertype) = struct.unpack_from(
            ofproto.OFP_ACTION_PUSH_PACK_STR, buf, offset)
        return cls(ethertype)

    def serialize(self, buf, offset):
        msg_pack_into(ofproto.OFP_ACTION_PUSH_PACK_STR, buf, offset,
                      self.type, self.len, self.ethertype)


@OFPAction.register_action_type(ofproto.OFPAT_POP_VLAN,
                                ofproto.OFP_ACTION_HEADER_SIZE)
class OFPActionPopVlan(OFPAction):
    """
    Pop VLAN action

    This action pops the outermost VLAN tag from the packet.
    """
    def __init__(self, type_=None, len_=None):
        super(OFPActionPopVlan, self).__init__()

    @classmethod
    def parser(cls, buf, offset):
        (type_, len_) = struct.unpack_from(
            ofproto.OFP_ACTION_HEADER_PACK_STR, buf, offset)
        return cls()


@OFPAction.register_action_type(ofproto.OFPAT_POP_MPLS,
                                ofproto.OFP_ACTION_POP_MPLS_SIZE)
class OFPActionPopMpls(OFPAction):
    """
    Pop MPLS action

    This action pops the MPLS header from the packet.
    """
    def __init__(self, ethertype=ether.ETH_TYPE_IP, type_=None, len_=None):
        super(OFPActionPopMpls, self).__init__()
        self.ethertype = ethertype

    @classmethod
    def parser(cls, buf, offset):
        (type_, len_, ethertype) = struct.unpack_from(
            ofproto.OFP_ACTION_POP_MPLS_PACK_STR, buf, offset)
        return cls(ethertype)

    def serialize(self, buf, offset):
        msg_pack_into(ofproto.OFP_ACTION_POP_MPLS_PACK_STR, buf, offset,
                      self.type, self.len, self.ethertype)


@OFPAction.register_action_type(ofproto.OFPAT_SET_FIELD,
                                ofproto.OFP_ACTION_SET_FIELD_SIZE)
class OFPActionSetField(OFPAction):
    """
    Set field action

    This action modifies a header field in the packet.

    The set of keywords available for this is same as OFPMatch.

    Example::

        set_field = OFPActionSetField(eth_src="00:00:00:00:00")
    """
    def __init__(self, field=None, **kwargs):
        # old api
        #   OFPActionSetField(field)
        # new api
        #   OFPActionSetField(eth_src="00:00:00:00:00")
        super(OFPActionSetField, self).__init__()
        if isinstance(field, OFPMatchField):
            # old api compat
            assert len(kwargs) == 0
            self.field = field
        else:
            # new api
            assert len(kwargs) == 1
            key = kwargs.keys()[0]
            value = kwargs[key]
            assert isinstance(key, (str, unicode))
            assert not isinstance(value, tuple)  # no mask
            self.key = key
            self.value = value

    @classmethod
    def parser(cls, buf, offset):
        (type_, len_) = struct.unpack_from(
            ofproto.OFP_ACTION_SET_FIELD_PACK_STR, buf, offset)
        (n, value, mask, _len) = ofproto.oxm_parse(buf, offset + 4)
        k, uv = ofproto.oxm_to_user(n, value, mask)
        action = cls(**{k: uv})
        action.len = len_

        # old api compat
        action.field = OFPMatchField.parser(buf, offset + 4)

        return action

    def serialize(self, buf, offset):
        # old api compat
        if self._composed_with_old_api():
            return self.serialize_old(buf, offset)

        n, value, mask = ofproto.oxm_from_user(self.key, self.value)
        len_ = ofproto.oxm_serialize(n, value, mask, buf, offset + 4)
        self.len = utils.round_up(4 + len_, 8)
        msg_pack_into('!HH', buf, offset, self.type, self.len)
        pad_len = self.len - (4 + len_)
        ofproto_parser.msg_pack_into("%dx" % pad_len, buf, offset + 4 + len_)

    # XXX old api compat
    def serialize_old(self, buf, offset):
        len_ = ofproto.OFP_ACTION_SET_FIELD_SIZE + self.field.oxm_len()
        self.len = utils.round_up(len_, 8)
        pad_len = self.len - len_

        msg_pack_into('!HH', buf, offset, self.type, self.len)
        self.field.serialize(buf, offset + 4)
        offset += len_
        ofproto_parser.msg_pack_into("%dx" % pad_len, buf, offset)

    # XXX old api compat
    def _composed_with_old_api(self):
        return not hasattr(self, 'value')

    def to_jsondict(self):
        # XXX old api compat
        if self._composed_with_old_api():
            # copy object first because serialize_old is destructive
            o2 = OFPActionSetField(self.field)
            # serialize and parse to fill new fields
            buf = bytearray()
            o2.serialize(buf, 0)
            o = OFPActionSetField.parser(str(buf), 0)
        else:
            o = self
        return {
            self.__class__.__name__: {
                'field': ofproto.oxm_to_jsondict(self.key, self.value)
            }
        }

    @classmethod
    def from_jsondict(cls, dict_):
        k, v = ofproto.oxm_from_jsondict(dict_['field'])
        o = OFPActionSetField(**{k: v})

        # XXX old api compat
        # serialize and parse to fill old attributes
        buf = bytearray()
        o.serialize(buf, 0)
        return OFPActionSetField.parser(str(buf), 0)

    # XXX old api compat
    def __str__(self):
        # XXX old api compat
        if self._composed_with_old_api():
            # copy object first because serialize_old is destructive
            o2 = OFPActionSetField(self.field)
            # serialize and parse to fill new fields
            buf = bytearray()
            o2.serialize(buf, 0)
            o = OFPActionSetField.parser(str(buf), 0)
        else:
            o = self
        return super(OFPActionSetField, o).__str__()

    __repr__ = __str__

    def stringify_attrs(self):
        yield (self.key, self.value)


@OFPAction.register_action_type(ofproto.OFPAT_PUSH_PBB,
                                ofproto.OFP_ACTION_PUSH_SIZE)
class OFPActionPushPbb(OFPAction):
    """
    Push PBB action

    This action pushes a new PBB header to the packet.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    ethertype        Ether type
    ================ ======================================================
    """
    def __init__(self, ethertype, type_=None, len_=None):
        super(OFPActionPushPbb, self).__init__()
        self.ethertype = ethertype

    @classmethod
    def parser(cls, buf, offset):
        (type_, len_, ethertype) = struct.unpack_from(
            ofproto.OFP_ACTION_PUSH_PACK_STR, buf, offset)
        return cls(ethertype)

    def serialize(self, buf, offset):
        msg_pack_into(ofproto.OFP_ACTION_PUSH_PACK_STR, buf, offset,
                      self.type, self.len, self.ethertype)


@OFPAction.register_action_type(ofproto.OFPAT_POP_PBB,
                                ofproto.OFP_ACTION_HEADER_SIZE)
class OFPActionPopPbb(OFPAction):
    """
    Pop PBB action

    This action pops the outermost PBB service instance header from
    the packet.
    """
    def __init__(self, type_=None, len_=None):
        super(OFPActionPopPbb, self).__init__()

    @classmethod
    def parser(cls, buf, offset):
        (type_, len_) = struct.unpack_from(
            ofproto.OFP_ACTION_HEADER_PACK_STR, buf, offset)
        return cls()

    @classmethod
    def parser(cls, buf, offset):
        (type_, len_) = struct.unpack_from(
            ofproto.OFP_ACTION_HEADER_PACK_STR, buf, offset)
        return cls()


@OFPAction.register_action_type(
    ofproto.OFPAT_EXPERIMENTER,
    ofproto.OFP_ACTION_EXPERIMENTER_HEADER_SIZE)
class OFPActionExperimenter(OFPAction):
    """
    Experimenter action

    This action is an extensible action for the experimenter.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    experimenter     Experimenter ID
    ================ ======================================================
    """
    def __init__(self, experimenter, data=None, type_=None, len_=None):
        super(OFPActionExperimenter, self).__init__()
        self.experimenter = experimenter
        self.data = data
        self.len = (utils.round_up(len(data), 8) +
                    ofproto.OFP_ACTION_EXPERIMENTER_HEADER_SIZE)

    @classmethod
    def parser(cls, buf, offset):
        (type_, len_, experimenter) = struct.unpack_from(
            ofproto.OFP_ACTION_EXPERIMENTER_HEADER_PACK_STR, buf, offset)
        data = buf[(offset + ofproto.OFP_ACTION_EXPERIMENTER_HEADER_SIZE
                    ): offset + len_]
        return cls(experimenter, data)

    def serialize(self, buf, offset):
        msg_pack_into(ofproto.OFP_ACTION_EXPERIMENTER_HEADER_PACK_STR,
                      buf, offset, self.type, self.len, self.experimenter)
        if self.data:
            buf += self.data


class OFPBucket(StringifyMixin):
    def __init__(self, weight=0, watch_port=ofproto.OFPP_ANY,
                 watch_group=ofproto.OFPG_ANY, actions=None, len_=None):
        super(OFPBucket, self).__init__()
        self.weight = weight
        self.watch_port = watch_port
        self.watch_group = watch_group
        self.actions = actions

    @classmethod
    def parser(cls, buf, offset):
        (len_, weight, watch_port, watch_group) = struct.unpack_from(
            ofproto.OFP_BUCKET_PACK_STR, buf, offset)
        msg = cls(weight, watch_port, watch_group, [])
        msg.len = len_

        length = ofproto.OFP_BUCKET_SIZE
        offset += ofproto.OFP_BUCKET_SIZE
        while length < msg.len:
            action = OFPAction.parser(buf, offset)
            msg.actions.append(action)
            offset += action.len
            length += action.len

        return msg

    def serialize(self, buf, offset):
        action_offset = offset + ofproto.OFP_BUCKET_SIZE
        action_len = 0
        for a in self.actions:
            a.serialize(buf, action_offset)
            action_offset += a.len
            action_len += a.len

        self.len = utils.round_up(ofproto.OFP_BUCKET_SIZE + action_len, 8)
        msg_pack_into(ofproto.OFP_BUCKET_PACK_STR, buf, offset,
                      self.len, self.weight, self.watch_port,
                      self.watch_group)


@_set_msg_type(ofproto.OFPT_GROUP_MOD)
class OFPGroupMod(MsgBase):
    """
    Modify group entry message

    The controller sends this message to modify the group table.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    command          One of the following values.

                     | OFPGC_ADD
                     | OFPGC_MODIFY
                     | OFPGC_DELETE
    type             One of the following values.

                     | OFPGT_ALL
                     | OFPGT_SELECT
                     | OFPGT_INDIRECT
                     | OFPGT_FF
    group_id         Group identifier
    buckets          list of ``OFPBucket``
    ================ ======================================================

    ``type`` attribute corresponds to ``type_`` parameter of __init__.

    Example::

        def send_group_mod(self, datapath):
            ofp = datapath.ofproto
            ofp_parser = datapath.ofproto_parser

            port = 1
            max_len = 2000
            actions = [ofp_parser.OFPActionOutput(port, max_len)]

            weight = 100
            watch_port = 0
            watch_group = 0
            buckets = [ofp_parser.OFPBucket(weight, watch_port, watch_group,
                                            actions)]

            group_id = 1
            req = ofp_parser.OFPGroupMod(datapath, ofp.OFPGC_ADD,
                                         ofp.OFPGT_SELECT, group_id, buckets)
            datapath.send_msg(req)
    """
    def __init__(self, datapath, command=ofproto.OFPGC_ADD,
                 type_=ofproto.OFPGT_ALL, group_id=0, buckets=[]):
        super(OFPGroupMod, self).__init__(datapath)
        self.command = command
        self.type = type_
        self.group_id = group_id
        self.buckets = buckets

    def _serialize_body(self):
        msg_pack_into(ofproto.OFP_GROUP_MOD_PACK_STR, self.buf,
                      ofproto.OFP_HEADER_SIZE,
                      self.command, self.type, self.group_id)

        offset = ofproto.OFP_GROUP_MOD_SIZE
        for b in self.buckets:
            b.serialize(self.buf, offset)
            offset += b.len


@_set_msg_type(ofproto.OFPT_PORT_MOD)
class OFPPortMod(MsgBase):
    """
    Port modification message

    The controller sneds this message to modify the behavior of the port.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    port_no          Port number to modify
    hw_addr          The hardware address that must be the same as hw_addr
                     of ``OFPPort`` of ``OFPSwitchFeatures``
    config           Bitmap of configuration flags.

                     | OFPPC_PORT_DOWN
                     | OFPPC_NO_RECV
                     | OFPPC_NO_FWD
                     | OFPPC_NO_PACKET_IN
    mask             Bitmap of configuration flags above to be changed
    advertise        Bitmap of the following flags.

                     | OFPPF_10MB_HD
                     | OFPPF_10MB_FD
                     | OFPPF_100MB_HD
                     | OFPPF_100MB_FD
                     | OFPPF_1GB_HD
                     | OFPPF_1GB_FD
                     | OFPPF_10GB_FD
                     | OFPPF_40GB_FD
                     | OFPPF_100GB_FD
                     | OFPPF_1TB_FD
                     | OFPPF_OTHER
                     | OFPPF_COPPER
                     | OFPPF_FIBER
                     | OFPPF_AUTONEG
                     | OFPPF_PAUSE
                     | OFPPF_PAUSE_ASYM
    ================ ======================================================

    Example::

        def send_port_mod(self, datapath):
            ofp = datapath.ofproto
            ofp_parser = datapath.ofproto_parser

            port_no = 3
            hw_addr = 'fa:c8:e8:76:1d:7e'
            config = 0
            mask = (ofp.OFPPC_PORT_DOWN | ofp.OFPPC_NO_RECV |
                    ofp.OFPPC_NO_FWD | ofp.OFPPC_NO_PACKET_IN)
            advertise = (ofp.OFPPF_10MB_HD | ofp.OFPPF_100MB_FD |
                         ofp.OFPPF_1GB_FD | ofp.OFPPF_COPPER |
                         ofp.OFPPF_AUTONEG | ofp.OFPPF_PAUSE |
                         ofp.OFPPF_PAUSE_ASYM)
            req = ofp_parser.OFPPortMod(datapath, port_no, hw_addr, config,
                                        mask, advertise)
            datapath.send_msg(req)
    """

    _TYPE = {
        'ascii': [
            'hw_addr',
        ]
    }

    def __init__(self, datapath, port_no=0, hw_addr='00:00:00:00:00:00',
                 config=0, mask=0, advertise=0):
        super(OFPPortMod, self).__init__(datapath)
        self.port_no = port_no
        self.hw_addr = hw_addr
        self.config = config
        self.mask = mask
        self.advertise = advertise

    def _serialize_body(self):
        msg_pack_into(ofproto.OFP_PORT_MOD_PACK_STR, self.buf,
                      ofproto.OFP_HEADER_SIZE,
                      self.port_no, addrconv.mac.text_to_bin(self.hw_addr),
                      self.config,
                      self.mask, self.advertise)


@_set_msg_type(ofproto.OFPT_METER_MOD)
class OFPMeterMod(MsgBase):
    """
    Meter modification message

    The controller sends this message to modify the meter.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    command          One of the following values.

                     | OFPMC_ADD
                     | OFPMC_MODIFY
                     | OFPMC_DELETE
    flags            Bitmap of the following flags.

                     | OFPMF_KBPS
                     | OFPMF_PKTPS
                     | OFPMF_BURST
                     | OFPMF_STATS
    meter_id         Meter instance
    bands            list of the following class instance.

                     | OFPMeterBandDrop
                     | OFPMeterBandDscpRemark
                     | OFPMeterBandExperimenter
    ================ ======================================================
    """
    def __init__(self, datapath, command=ofproto.OFPMC_ADD,
                 flags=ofproto.OFPMF_KBPS, meter_id=1, bands=[]):
        super(OFPMeterMod, self).__init__(datapath)
        self.command = command
        self.flags = flags
        self.meter_id = meter_id
        self.bands = bands

    def _serialize_body(self):
        msg_pack_into(ofproto.OFP_METER_MOD_PACK_STR, self.buf,
                      ofproto.OFP_HEADER_SIZE,
                      self.command, self.flags, self.meter_id)

        offset = ofproto.OFP_METER_MOD_SIZE
        for b in self.bands:
            b.serialize(self.buf, offset)
            offset += b.len


@_set_msg_type(ofproto.OFPT_TABLE_MOD)
class OFPTableMod(MsgBase):
    """
    Flow table configuration message

    The controller sends this message to configure table state.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    table_id         ID of the table (OFPTT_ALL indicates all tables)
    config           Bitmap of the following flags.
                     OFPTC_DEPRECATED_MASK (3)
    ================ ======================================================

    Example::

        def send_table_mod(self, datapath):
            ofp = datapath.ofproto
            ofp_parser = datapath.ofproto_parser

            req = ofp_parser.OFPTableMod(datapath, 1, 3)
            datapath.send_msg(req)
    """
    def __init__(self, datapath, table_id, config):
        super(OFPTableMod, self).__init__(datapath)
        self.table_id = table_id
        self.config = config

    def _serialize_body(self):
        msg_pack_into(ofproto.OFP_TABLE_MOD_PACK_STR, self.buf,
                      ofproto.OFP_HEADER_SIZE,
                      self.table_id, self.config)


def _set_stats_type(stats_type, stats_body_cls):
    def _set_cls_stats_type(cls):
        cls.cls_stats_type = stats_type
        cls.cls_stats_body_cls = stats_body_cls
        return cls
    return _set_cls_stats_type


@_set_msg_type(ofproto.OFPT_MULTIPART_REQUEST)
class OFPMultipartRequest(MsgBase):
    def __init__(self, datapath, flags):
        super(OFPMultipartRequest, self).__init__(datapath)
        self.type = self.__class__.cls_stats_type
        self.flags = flags

    def _serialize_stats_body(self):
        pass

    def _serialize_body(self):
        msg_pack_into(ofproto.OFP_MULTIPART_REQUEST_PACK_STR,
                      self.buf, ofproto.OFP_HEADER_SIZE,
                      self.type, self.flags)
        self._serialize_stats_body()


@_register_parser
@_set_msg_type(ofproto.OFPT_MULTIPART_REPLY)
class OFPMultipartReply(MsgBase):
    _STATS_MSG_TYPES = {}

    @staticmethod
    def register_stats_type(body_single_struct=False):
        def _register_stats_type(cls):
            assert cls.cls_stats_type is not None
            assert cls.cls_stats_type not in OFPMultipartReply._STATS_MSG_TYPES
            assert cls.cls_stats_body_cls is not None
            cls.cls_body_single_struct = body_single_struct
            OFPMultipartReply._STATS_MSG_TYPES[cls.cls_stats_type] = cls
            return cls
        return _register_stats_type

    def __init__(self, datapath, body=None, flags=None):
        super(OFPMultipartReply, self).__init__(datapath)
        self.body = body
        self.flags = flags

    @classmethod
    def parser_stats_body(cls, buf, msg_len, offset):
        body_cls = cls.cls_stats_body_cls
        body = []
        while offset < msg_len:
            entry = body_cls.parser(buf, offset)
            body.append(entry)
            offset += entry.length

        if cls.cls_body_single_struct:
            return body[0]
        return body

    @classmethod
    def parser_stats(cls, datapath, version, msg_type, msg_len, xid, buf):
        msg = MsgBase.parser.__func__(
            cls, datapath, version, msg_type, msg_len, xid, buf)
        msg.body = msg.parser_stats_body(msg.buf, msg.msg_len,
                                         ofproto.OFP_MULTIPART_REPLY_SIZE)
        return msg

    @classmethod
    def parser(cls, datapath, version, msg_type, msg_len, xid, buf):
        type_, flags = struct.unpack_from(
            ofproto.OFP_MULTIPART_REPLY_PACK_STR, buffer(buf),
            ofproto.OFP_HEADER_SIZE)
        stats_type_cls = cls._STATS_MSG_TYPES.get(type_)
        msg = super(OFPMultipartReply, stats_type_cls).parser(
            datapath, version, msg_type, msg_len, xid, buf)
        msg.type = type_
        msg.flags = flags

        offset = ofproto.OFP_MULTIPART_REPLY_SIZE
        body = []
        while offset < msg_len:
            b = stats_type_cls.cls_stats_body_cls.parser(msg.buf, offset)
            body.append(b)
            offset += b.length if hasattr(b, 'length') else b.len

        if stats_type_cls.cls_body_single_struct:
            msg.body = body[0]
        else:
            msg.body = body
        return msg


class OFPDescStats(ofproto_parser.namedtuple('OFPDescStats', (
        'mfr_desc', 'hw_desc', 'sw_desc', 'serial_num', 'dp_desc'))):

    _TYPE = {
        'ascii': [
            'mfr_desc',
            'hw_desc',
            'sw_desc',
            'serial_num',
            'dp_desc',
        ]
    }

    @classmethod
    def parser(cls, buf, offset):
        desc = struct.unpack_from(ofproto.OFP_DESC_PACK_STR,
                                  buf, offset)
        desc = list(desc)
        desc = map(lambda x: x.rstrip('\0'), desc)
        stats = cls(*desc)
        stats.length = ofproto.OFP_DESC_SIZE
        return stats


@_set_stats_type(ofproto.OFPMP_DESC, OFPDescStats)
@_set_msg_type(ofproto.OFPT_MULTIPART_REQUEST)
class OFPDescStatsRequest(OFPMultipartRequest):
    """
    Description statistics request message

    The controller uses this message to query description of the switch.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    flags            Zero or ``OFPMPF_REQ_MORE``
    ================ ======================================================

    Example::

        def send_desc_stats_request(self, datapath):
            ofp = datapath.ofproto
            ofp_parser = datapath.ofproto_parser

            req = ofp_parser.OFPDescStatsRequest(datapath, 0)
            datapath.send_msg(req)
    """
    def __init__(self, datapath, flags=0, type_=None):
        super(OFPDescStatsRequest, self).__init__(datapath, flags)


@OFPMultipartReply.register_stats_type(body_single_struct=True)
@_set_stats_type(ofproto.OFPMP_DESC, OFPDescStats)
@_set_msg_type(ofproto.OFPT_MULTIPART_REPLY)
class OFPDescStatsReply(OFPMultipartReply):
    """
    Description statistics reply message

    The switch responds with this message to a description statistics
    request.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    body             Instance of ``OFPDescStats``
    ================ ======================================================

    Example::

        @set_ev_cls(ofp_event.EventOFPDescStatsReply, MAIN_DISPATCHER)
        def desc_stats_reply_handler(self, ev):
            body = ev.msg.body

            self.logger.debug('DescStats: mfr_desc=%s hw_desc=%s sw_desc=%s '
                              'serial_num=%s dp_desc=%s',
                              body.mfr_desc, body.hw_desc, body.sw_desc,
                              body.serial_num, body.dp_desc)
    """
    def __init__(self, datapath, type_=None, **kwargs):
        super(OFPDescStatsReply, self).__init__(datapath, **kwargs)


class OFPFlowStats(StringifyMixin):
    def __init__(self, table_id=None, duration_sec=None, duration_nsec=None,
                 priority=None, idle_timeout=None, hard_timeout=None,
                 flags=None, cookie=None, packet_count=None,
                 byte_count=None, match=None, instructions=None,
                 length=None):
        super(OFPFlowStats, self).__init__()
        self.length = 0
        self.table_id = table_id
        self.duration_sec = duration_sec
        self.duration_nsec = duration_nsec
        self.priority = priority
        self.idle_timeout = idle_timeout
        self.hard_timeout = hard_timeout
        self.flags = flags
        self.cookie = cookie
        self.packet_count = packet_count
        self.byte_count = byte_count
        self.match = match
        self.instructions = instructions

    @classmethod
    def parser(cls, buf, offset):
        flow_stats = cls()

        (flow_stats.length, flow_stats.table_id,
         flow_stats.duration_sec, flow_stats.duration_nsec,
         flow_stats.priority, flow_stats.idle_timeout,
         flow_stats.hard_timeout, flow_stats.flags,
         flow_stats.cookie, flow_stats.packet_count,
         flow_stats.byte_count) = struct.unpack_from(
            ofproto.OFP_FLOW_STATS_0_PACK_STR, buf, offset)
        offset += ofproto.OFP_FLOW_STATS_0_SIZE

        flow_stats.match = OFPMatch.parser(buf, offset)
        match_length = utils.round_up(flow_stats.match.length, 8)
        inst_length = (flow_stats.length - (ofproto.OFP_FLOW_STATS_SIZE -
                                            ofproto.OFP_MATCH_SIZE +
                                            match_length))
        offset += match_length
        instructions = []
        while inst_length > 0:
            inst = OFPInstruction.parser(buf, offset)
            instructions.append(inst)
            offset += inst.len
            inst_length -= inst.len

        flow_stats.instructions = instructions
        return flow_stats


class OFPFlowStatsRequestBase(OFPMultipartRequest):
    def __init__(self, datapath, flags, table_id, out_port, out_group,
                 cookie, cookie_mask, match):
        super(OFPFlowStatsRequestBase, self).__init__(datapath, flags)
        self.table_id = table_id
        self.out_port = out_port
        self.out_group = out_group
        self.cookie = cookie
        self.cookie_mask = cookie_mask
        self.match = match

    def _serialize_stats_body(self):
        offset = ofproto.OFP_MULTIPART_REQUEST_SIZE
        msg_pack_into(ofproto.OFP_FLOW_STATS_REQUEST_0_PACK_STR,
                      self.buf, offset, self.table_id, self.out_port,
                      self.out_group, self.cookie, self.cookie_mask)

        offset += ofproto.OFP_FLOW_STATS_REQUEST_0_SIZE
        self.match.serialize(self.buf, offset)


@_set_stats_type(ofproto.OFPMP_FLOW, OFPFlowStats)
@_set_msg_type(ofproto.OFPT_MULTIPART_REQUEST)
class OFPFlowStatsRequest(OFPFlowStatsRequestBase):
    """
    Individual flow statistics request message

    The controller uses this message to query individual flow statistics.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    flags            Zero or ``OFPMPF_REQ_MORE``
    table_id         ID of table to read
    out_port         Require matching entries to include this as an output
                     port
    out_group        Require matching entries to include this as an output
                     group
    cookie           Require matching entries to contain this cookie value
    cookie_mask      Mask used to restrict the cookie bits that must match
    match            Instance of ``OFPMatch``
    ================ ======================================================

    Example::

        def send_flow_stats_request(self, datapath):
            ofp = datapath.ofproto
            ofp_parser = datapath.ofproto_parser

            cookie = cookie_mask = 0
            match = ofp_parser.OFPMatch(in_port=1)
            req = ofp_parser.OFPFlowStatsRequest(datapath, 0,
                                                 ofp.OFPTT_ALL,
                                                 ofp.OFPP_ANY, ofp.OFPG_ANY,
                                                 cookie, cookie_mask,
                                                 match)
            datapath.send_msg(req)
    """
    def __init__(self, datapath, flags=0, table_id=ofproto.OFPTT_ALL,
                 out_port=ofproto.OFPP_ANY,
                 out_group=ofproto.OFPG_ANY,
                 cookie=0, cookie_mask=0, match=None, type_=None):
        if match is None:
            match = OFPMatch()
        super(OFPFlowStatsRequest, self).__init__(datapath, flags, table_id,
                                                  out_port, out_group,
                                                  cookie, cookie_mask, match)


@OFPMultipartReply.register_stats_type()
@_set_stats_type(ofproto.OFPMP_FLOW, OFPFlowStats)
@_set_msg_type(ofproto.OFPT_MULTIPART_REPLY)
class OFPFlowStatsReply(OFPMultipartReply):
    """
    Individual flow statistics reply message

    The switch responds with this message to an individual flow statistics
    request.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    body             List of ``OFPFlowStats`` instance
    ================ ======================================================

    Example::

        @set_ev_cls(ofp_event.EventOFPFlowStatsReply, MAIN_DISPATCHER)
        def flow_stats_reply_handler(self, ev):
            flows = []
            for stat in ev.msg.body:
                flows.append('table_id=%s '
                             'duration_sec=%d duration_nsec=%d '
                             'priority=%d '
                             'idle_timeout=%d hard_timeout=%d flags=0x%04x '
                             'cookie=%d packet_count=%d byte_count=%d '
                             'match=%s instructions=%s' %
                             (stat.table_id,
                              stat.duration_sec, stat.duration_nsec,
                              stat.priority,
                              stat.idle_timeout, stat.hard_timeout, stat.flags,
                              stat.cookie, stat.packet_count, stat.byte_count,
                              stat.match, stat.instructions))
            self.logger.debug('FlowStats: %s', flows)
    """
    def __init__(self, datapath, type_=None, **kwargs):
        super(OFPFlowStatsReply, self).__init__(datapath, **kwargs)


class OFPAggregateStats(ofproto_parser.namedtuple('OFPAggregateStats', (
        'packet_count', 'byte_count', 'flow_count'))):
    @classmethod
    def parser(cls, buf, offset):
        agg = struct.unpack_from(
            ofproto.OFP_AGGREGATE_STATS_REPLY_PACK_STR, buf, offset)
        stats = cls(*agg)
        stats.length = ofproto.OFP_AGGREGATE_STATS_REPLY_SIZE
        return stats


@_set_stats_type(ofproto.OFPMP_AGGREGATE, OFPAggregateStats)
@_set_msg_type(ofproto.OFPT_MULTIPART_REQUEST)
class OFPAggregateStatsRequest(OFPFlowStatsRequestBase):
    """
    Aggregate flow statistics request message

    The controller uses this message to query aggregate flow statictics.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    flags            Zero or ``OFPMPF_REQ_MORE``
    table_id         ID of table to read
    out_port         Require matching entries to include this as an output
                     port
    out_group        Require matching entries to include this as an output
                     group
    cookie           Require matching entries to contain this cookie value
    cookie_mask      Mask used to restrict the cookie bits that must match
    match            Instance of ``OFPMatch``
    ================ ======================================================

    Example::

        def send_aggregate_stats_request(self, datapath):
            ofp = datapath.ofproto
            ofp_parser = datapath.ofproto_parser

            cookie = cookie_mask = 0
            match = ofp_parser.OFPMatch(in_port=1)
            req = ofp_parser.OFPAggregateStatsRequest(datapath, 0,
                                                      ofp.OFPTT_ALL,
                                                      ofp.OFPP_ANY,
                                                      ofp.OFPG_ANY,
                                                      cookie, cookie_mask,
                                                      match)
            datapath.send_msg(req)
    """
    def __init__(self, datapath, flags, table_id, out_port, out_group,
                 cookie, cookie_mask, match, type_=None):
        super(OFPAggregateStatsRequest, self).__init__(datapath,
                                                       flags,
                                                       table_id,
                                                       out_port,
                                                       out_group,
                                                       cookie,
                                                       cookie_mask,
                                                       match)


@OFPMultipartReply.register_stats_type(body_single_struct=True)
@_set_stats_type(ofproto.OFPMP_AGGREGATE, OFPAggregateStats)
@_set_msg_type(ofproto.OFPT_MULTIPART_REPLY)
class OFPAggregateStatsReply(OFPMultipartReply):
    """
    Aggregate flow statistics reply message

    The switch responds with this message to an aggregate flow statistics
    request.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    body             Instance of ``OFPAggregateStats``
    ================ ======================================================

    Example::

        @set_ev_cls(ofp_event.EventOFPAggregateStatsReply, MAIN_DISPATCHER)
        def aggregate_stats_reply_handler(self, ev):
            body = ev.msg.body

            self.logger.debug('AggregateStats: packet_count=%d byte_count=%d '
                              'flow_count=%d',
                              body.packet_count, body.byte_count,
                              body.flow_count)
    """
    def __init__(self, datapath, type_=None, **kwargs):
        super(OFPAggregateStatsReply, self).__init__(datapath, **kwargs)


class OFPTableStats(ofproto_parser.namedtuple('OFPTableStats', (
        'table_id', 'active_count', 'lookup_count',
        'matched_count'))):
    @classmethod
    def parser(cls, buf, offset):
        tbl = struct.unpack_from(ofproto.OFP_TABLE_STATS_PACK_STR,
                                 buf, offset)
        stats = cls(*tbl)
        stats.length = ofproto.OFP_TABLE_STATS_SIZE
        return stats


@_set_stats_type(ofproto.OFPMP_TABLE, OFPTableStats)
@_set_msg_type(ofproto.OFPT_MULTIPART_REQUEST)
class OFPTableStatsRequest(OFPMultipartRequest):
    """
    Table statistics request message

    The controller uses this message to query flow table statictics.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    flags            Zero or ``OFPMPF_REQ_MORE``
    ================ ======================================================

    Example::

        def send_table_stats_request(self, datapath):
            ofp = datapath.ofproto
            ofp_parser = datapath.ofproto_parser

            req = ofp_parser.OFPTableStatsRequest(datapath, 0)
            datapath.send_msg(req)
    """
    def __init__(self, datapath, flags=0, type_=None):
        super(OFPTableStatsRequest, self).__init__(datapath, flags)


@OFPMultipartReply.register_stats_type()
@_set_stats_type(ofproto.OFPMP_TABLE, OFPTableStats)
@_set_msg_type(ofproto.OFPT_MULTIPART_REPLY)
class OFPTableStatsReply(OFPMultipartReply):
    """
    Table statistics reply message

    The switch responds with this message to a table statistics request.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    body             List of ``OFPTableStats`` instance
    ================ ======================================================

    Example::

        @set_ev_cls(ofp_event.EventOFPTableStatsReply, MAIN_DISPATCHER)
        def table_stats_reply_handler(self, ev):
            tables = []
            for stat in ev.msg.body:
                tables.append('table_id=%d active_count=%d lookup_count=%d '
                              ' matched_count=%d' %
                              (stat.table_id, stat.active_count,
                               stat.lookup_count, stat.matched_count))
             self.logger.debug('TableStats: %s', tables)
    """
    def __init__(self, datapath, type_=None, **kwargs):
        super(OFPTableStatsReply, self).__init__(datapath, **kwargs)


class OFPPortStats(ofproto_parser.namedtuple('OFPPortStats', (
        'port_no', 'rx_packets', 'tx_packets', 'rx_bytes', 'tx_bytes',
        'rx_dropped', 'tx_dropped', 'rx_errors', 'tx_errors',
        'rx_frame_err', 'rx_over_err', 'rx_crc_err', 'collisions',
        'duration_sec', 'duration_nsec'))):
    @classmethod
    def parser(cls, buf, offset):
        port = struct.unpack_from(ofproto.OFP_PORT_STATS_PACK_STR,
                                  buf, offset)
        stats = cls(*port)
        stats.length = ofproto.OFP_PORT_STATS_SIZE
        return stats


@_set_stats_type(ofproto.OFPMP_PORT_STATS, OFPPortStats)
@_set_msg_type(ofproto.OFPT_MULTIPART_REQUEST)
class OFPPortStatsRequest(OFPMultipartRequest):
    """
    Port statistics request message

    The controller uses this message to query information about ports
    statistics.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    flags            Zero or ``OFPMPF_REQ_MORE``
    port_no          Port number to read (OFPP_ANY to all ports)
    ================ ======================================================

    Example::

        def send_port_stats_request(self, datapath):
            ofp = datapath.ofproto
            ofp_parser = datapath.ofproto_parser

            req = ofp_parser.OFPPortStatsRequest(datapath, 0, ofp.OFPP_ANY)
            datapath.send_msg(req)
    """
    def __init__(self, datapath, flags=0, port_no=ofproto.OFPP_ANY,
                 type_=None):
        super(OFPPortStatsRequest, self).__init__(datapath, flags)
        self.port_no = port_no

    def _serialize_stats_body(self):
        msg_pack_into(ofproto.OFP_PORT_STATS_REQUEST_PACK_STR,
                      self.buf,
                      ofproto.OFP_MULTIPART_REQUEST_SIZE,
                      self.port_no)


@OFPMultipartReply.register_stats_type()
@_set_stats_type(ofproto.OFPMP_PORT_STATS, OFPPortStats)
@_set_msg_type(ofproto.OFPT_MULTIPART_REPLY)
class OFPPortStatsReply(OFPMultipartReply):
    """
    Port statistics reply message

    The switch responds with this message to a port statistics request.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    body             List of ``OFPPortStats`` instance
    ================ ======================================================

    Example::

        @set_ev_cls(ofp_event.EventOFPPortStatsReply, MAIN_DISPATCHER)
        def port_stats_reply_handler(self, ev):
            ports = []
            for stat in ev.msg.body:
                ports.append('port_no=%d '
                             'rx_packets=%d tx_packets=%d '
                             'rx_bytes=%d tx_bytes=%d '
                             'rx_dropped=%d tx_dropped=%d '
                             'rx_errors=%d tx_errors=%d '
                             'rx_frame_err=%d rx_over_err=%d rx_crc_err=%d '
                             'collisions=%d duration_sec=%d duration_nsec=%d' %
                             (stat.port_no,
                              stat.rx_packets, stat.tx_packets,
                              stat.rx_bytes, stat.tx_bytes,
                              stat.rx_dropped, stat.tx_dropped,
                              stat.rx_errors, stat.tx_errors,
                              stat.rx_frame_err, stat.rx_over_err,
                              stat.rx_crc_err, stat.collisions,
                              stat.duration_sec, stat.duration_nsec))
        self.logger.debug('PortStats: %s', ports)
    """
    def __init__(self, datapath, type_=None, **kwargs):
        super(OFPPortStatsReply, self).__init__(datapath, **kwargs)


class OFPQueueStats(ofproto_parser.namedtuple('OFPQueueStats', (
        'port_no', 'queue_id', 'tx_bytes', 'tx_packets', 'tx_errors',
        'duration_sec', 'duration_nsec'))):
    @classmethod
    def parser(cls, buf, offset):
        queue = struct.unpack_from(ofproto.OFP_QUEUE_STATS_PACK_STR,
                                   buf, offset)
        stats = cls(*queue)
        stats.length = ofproto.OFP_QUEUE_STATS_SIZE
        return stats


@_set_stats_type(ofproto.OFPMP_QUEUE, OFPQueueStats)
@_set_msg_type(ofproto.OFPT_MULTIPART_REQUEST)
class OFPQueueStatsRequest(OFPMultipartRequest):
    """
    Queue statistics request message

    The controller uses this message to query queue statictics.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    flags            Zero or ``OFPMPF_REQ_MORE``
    port_no          Port number to read
    queue_id         ID of queue to read
    ================ ======================================================

    Example::

        def send_queue_stats_request(self, datapath):
            ofp = datapath.ofproto
            ofp_parser = datapath.ofproto_parser

            req = ofp_parser.OFPQueueStatsRequest(datapath, 0, ofp.OFPP_ANY,
                                                  ofp.OFPQ_ALL)
            datapath.send_msg(req)
    """
    def __init__(self, datapath, flags=0, port_no=ofproto.OFPP_ANY,
                 queue_id=ofproto.OFPQ_ALL, type_=None):
        super(OFPQueueStatsRequest, self).__init__(datapath, flags)
        self.port_no = port_no
        self.queue_id = queue_id

    def _serialize_stats_body(self):
        msg_pack_into(ofproto.OFP_QUEUE_STATS_REQUEST_PACK_STR,
                      self.buf,
                      ofproto.OFP_MULTIPART_REQUEST_SIZE,
                      self.port_no, self.queue_id)


@OFPMultipartReply.register_stats_type()
@_set_stats_type(ofproto.OFPMP_QUEUE, OFPQueueStats)
@_set_msg_type(ofproto.OFPT_MULTIPART_REPLY)
class OFPQueueStatsReply(OFPMultipartReply):
    """
    Queue statistics reply message

    The switch responds with this message to an aggregate flow statistics
    request.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    body             List of ``OFPQueueStats`` instance
    ================ ======================================================

    Example::

        @set_ev_cls(ofp_event.EventOFPQueueStatsReply, MAIN_DISPATCHER)
        def queue_stats_reply_handler(self, ev):
            queues = []
            for stat in ev.msg.body:
                queues.append('port_no=%d queue_id=%d '
                              'tx_bytes=%d tx_packets=%d tx_errors=%d '
                              'duration_sec=%d duration_nsec=%d' %
                              (stat.port_no, stat.queue_id,
                               stat.tx_bytes, stat.tx_packets, stat.tx_errors,
                               stat.duration_sec, stat.duration_nsec))
            self.logger.debug('QueueStats: %s', queues)
    """
    def __init__(self, datapath, type_=None, **kwargs):
        super(OFPQueueStatsReply, self).__init__(datapath, **kwargs)


class OFPBucketCounter(StringifyMixin):
    def __init__(self, packet_count, byte_count):
        super(OFPBucketCounter, self).__init__()
        self.packet_count = packet_count
        self.byte_count = byte_count

    @classmethod
    def parser(cls, buf, offset):
        packet_count, byte_count = struct.unpack_from(
            ofproto.OFP_BUCKET_COUNTER_PACK_STR, buf, offset)
        return cls(packet_count, byte_count)


class OFPGroupStats(StringifyMixin):
    def __init__(self, length=None, group_id=None, ref_count=None,
                 packet_count=None, byte_count=None, duration_sec=None,
                 duration_nsec=None, bucket_stats=None):
        super(OFPGroupStats, self).__init__()
        self.length = length
        self.group_id = group_id
        self.ref_count = ref_count
        self.packet_count = packet_count
        self.byte_count = byte_count
        self.duration_sec = duration_sec
        self.duration_nsec = duration_nsec
        self.bucket_stats = bucket_stats

    @classmethod
    def parser(cls, buf, offset):
        group = struct.unpack_from(ofproto.OFP_GROUP_STATS_PACK_STR,
                                   buf, offset)
        group_stats = cls(*group)

        group_stats.bucket_stats = []
        total_len = group_stats.length + offset
        offset += ofproto.OFP_GROUP_STATS_SIZE
        while total_len > offset:
            b = OFPBucketCounter.parser(buf, offset)
            group_stats.bucket_stats.append(b)
            offset += ofproto.OFP_BUCKET_COUNTER_SIZE

        return group_stats


@_set_stats_type(ofproto.OFPMP_GROUP, OFPGroupStats)
@_set_msg_type(ofproto.OFPT_MULTIPART_REQUEST)
class OFPGroupStatsRequest(OFPMultipartRequest):
    """
    Group statistics request message

    The controller uses this message to query statistics of one or more
    groups.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    flags            Zero or ``OFPMPF_REQ_MORE``
    group_id         ID of group to read (OFPG_ALL to all groups)
    ================ ======================================================

    Example::

        def send_group_stats_request(self, datapath):
            ofp = datapath.ofproto
            ofp_parser = datapath.ofproto_parser

            req = ofp_parser.OFPGroupStatsRequest(datapath, 0, ofp.OFPG_ALL)
            datapath.send_msg(req)
    """
    def __init__(self, datapath, flags=0, group_id=ofproto.OFPG_ALL,
                 type_=None):
        super(OFPGroupStatsRequest, self).__init__(datapath, flags)
        self.group_id = group_id

    def _serialize_stats_body(self):
        msg_pack_into(ofproto.OFP_GROUP_STATS_REQUEST_PACK_STR,
                      self.buf,
                      ofproto.OFP_MULTIPART_REQUEST_SIZE,
                      self.group_id)


@OFPMultipartReply.register_stats_type()
@_set_stats_type(ofproto.OFPMP_GROUP, OFPGroupStats)
@_set_msg_type(ofproto.OFPT_MULTIPART_REPLY)
class OFPGroupStatsReply(OFPMultipartReply):
    """
    Group statistics reply message

    The switch responds with this message to a group statistics request.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    body             List of ``OFPGroupStats`` instance
    ================ ======================================================

    Example::

        @set_ev_cls(ofp_event.EventOFPGroupStatsReply, MAIN_DISPATCHER)
        def group_stats_reply_handler(self, ev):
            groups = []
            for stat in ev.msg.body:
                groups.append('length=%d group_id=%d '
                              'ref_count=%d packet_count=%d byte_count=%d '
                              'duration_sec=%d duration_nsec=%d' %
                              (stat.length, stat.group_id,
                               stat.ref_count, stat.packet_count,
                               stat.byte_count, stat.duration_sec,
                               stat.duration_nsec))
            self.logger.debug('GroupStats: %s', groups)
    """
    def __init__(self, datapath, type_=None, **kwargs):
        super(OFPGroupStatsReply, self).__init__(datapath, **kwargs)


class OFPGroupDescStats(StringifyMixin):
    def __init__(self, type_=None, group_id=None, buckets=None, length=None):
        super(OFPGroupDescStats, self).__init__()
        self.type = type_
        self.group_id = group_id
        self.buckets = buckets

    @classmethod
    def parser(cls, buf, offset):
        stats = cls()

        (stats.length, stats.type, stats.group_id) = struct.unpack_from(
            ofproto.OFP_GROUP_DESC_STATS_PACK_STR, buf, offset)
        offset += ofproto.OFP_GROUP_DESC_STATS_SIZE

        stats.buckets = []
        length = ofproto.OFP_GROUP_DESC_STATS_SIZE
        while length < stats.length:
            bucket = OFPBucket.parser(buf, offset)
            stats.buckets.append(bucket)

            offset += bucket.len
            length += bucket.len

        return stats


@_set_stats_type(ofproto.OFPMP_GROUP_DESC, OFPGroupDescStats)
@_set_msg_type(ofproto.OFPT_MULTIPART_REQUEST)
class OFPGroupDescStatsRequest(OFPMultipartRequest):
    """
    Group description request message

    The controller uses this message to list the set of groups on a switch.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    flags            Zero or ``OFPMPF_REQ_MORE``
    ================ ======================================================

    Example::

        def send_group_desc_stats_request(self, datapath):
            ofp = datapath.ofproto
            ofp_parser = datapath.ofproto_parser

            req = ofp_parser.OFPGroupDescStatsRequest(datapath, 0)
            datapath.send_msg(req)
    """
    def __init__(self, datapath, flags=0, type_=None):
        super(OFPGroupDescStatsRequest, self).__init__(datapath, flags)


@OFPMultipartReply.register_stats_type()
@_set_stats_type(ofproto.OFPMP_GROUP_DESC, OFPGroupDescStats)
@_set_msg_type(ofproto.OFPT_MULTIPART_REPLY)
class OFPGroupDescStatsReply(OFPMultipartReply):
    """
    Group description reply message

    The switch responds with this message to a group description request.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    body             List of ``OFPGroupDescStats`` instance
    ================ ======================================================

    Example::

        @set_ev_cls(ofp_event.EventOFPGroupDescStatsReply, MAIN_DISPATCHER)
        def group_desc_stats_reply_handler(self, ev):
            descs = []
            for stat in ev.msg.body:
                descs.append('length=%d type=%d group_id=%d '
                             'buckets=%s' %
                             (stat.length, stat.type, stat.group_id,
                              stat.bucket))
            self.logger.debug('GroupDescStats: %s', groups)
    """
    def __init__(self, datapath, type_=None, **kwargs):
        super(OFPGroupDescStatsReply, self).__init__(datapath, **kwargs)


class OFPGroupFeaturesStats(ofproto_parser.namedtuple('OFPGroupFeaturesStats',
                            ('types', 'capabilities', 'max_groups',
                             'actions'))):
    @classmethod
    def parser(cls, buf, offset):
        group_features = struct.unpack_from(
            ofproto.OFP_GROUP_FEATURES_PACK_STR, buf, offset)
        types = group_features[0]
        capabilities = group_features[1]
        max_groups = list(group_features[2:6])
        actions = list(group_features[6:10])
        stats = cls(types, capabilities, max_groups, actions)
        stats.length = ofproto.OFP_GROUP_FEATURES_SIZE
        return stats


@_set_stats_type(ofproto.OFPMP_GROUP_FEATURES, OFPGroupFeaturesStats)
@_set_msg_type(ofproto.OFPT_MULTIPART_REQUEST)
class OFPGroupFeaturesStatsRequest(OFPMultipartRequest):
    """
    Group features request message

    The controller uses this message to list the capabilities of groups on
    a switch.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    flags            Zero or ``OFPMPF_REQ_MORE``
    ================ ======================================================

    Example::

        def send_group_features_stats_request(self, datapath):
            ofp = datapath.ofproto
            ofp_parser = datapath.ofproto_parser

            req = ofp_parser.OFPGroupFeaturesStatsRequest(datapath, 0)
            datapath.send_msg(req)
    """
    def __init__(self, datapath, flags=0, type_=None):
        super(OFPGroupFeaturesStatsRequest, self).__init__(datapath, flags)


@OFPMultipartReply.register_stats_type(body_single_struct=True)
@_set_stats_type(ofproto.OFPMP_GROUP_FEATURES, OFPGroupFeaturesStats)
@_set_msg_type(ofproto.OFPT_MULTIPART_REPLY)
class OFPGroupFeaturesStatsReply(OFPMultipartReply):
    """
    Group features reply message

    The switch responds with this message to a group features request.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    body             Instance of ``OFPGroupFeaturesStats``
    ================ ======================================================

    Example::

        @set_ev_cls(ofp_event.EventOFPGroupFeaturesStatsReply, MAIN_DISPATCHER)
        def group_features_stats_reply_handler(self, ev):
            body = ev.msg.body

            self.logger.debug('GroupFeaturesStats: types=%d '
                              'capabilities=0x%08x max_groups=%s '
                              'actions=%s',
                              body.types, body.capabilities,
                              body.max_groups, body.actions)
    """
    def __init__(self, datapath, type_=None, **kwargs):
        super(OFPGroupFeaturesStatsReply, self).__init__(datapath, **kwargs)


class OFPMeterBandStats(StringifyMixin):
    def __init__(self, packet_band_count, byte_band_count):
        super(OFPMeterBandStats, self).__init__()
        self.packet_band_count = packet_band_count
        self.byte_band_count = byte_band_count

    @classmethod
    def parser(cls, buf, offset):
        band_stats = struct.unpack_from(
            ofproto.OFP_METER_BAND_STATS_PACK_STR, buf, offset)
        return cls(*band_stats)


class OFPMeterStats(StringifyMixin):
    def __init__(self, meter_id=None, flow_count=None, packet_in_count=None,
                 byte_in_count=None, duration_sec=None, duration_nsec=None,
                 band_stats=None, len_=None):
        super(OFPMeterStats, self).__init__()
        self.meter_id = meter_id
        self.len = 0
        self.flow_count = flow_count
        self.packet_in_count = packet_in_count
        self.byte_in_count = byte_in_count
        self.duration_sec = duration_sec
        self.duration_nsec = duration_nsec
        self.band_stats = band_stats

    @classmethod
    def parser(cls, buf, offset):
        meter_stats = cls()

        (meter_stats.meter_id, meter_stats.len,
         meter_stats.flow_count, meter_stats.packet_in_count,
         meter_stats.byte_in_count, meter_stats.duration_sec,
         meter_stats.duration_nsec) = struct.unpack_from(
            ofproto.OFP_METER_STATS_PACK_STR, buf, offset)
        offset += ofproto.OFP_METER_STATS_SIZE

        meter_stats.band_stats = []
        length = ofproto.OFP_METER_STATS_SIZE
        while length < meter_stats.len:
            band_stats = OFPMeterBandStats.parser(buf, offset)
            meter_stats.band_stats.append(band_stats)
            offset += ofproto.OFP_METER_BAND_STATS_SIZE
            length += ofproto.OFP_METER_BAND_STATS_SIZE

        return meter_stats


@_set_stats_type(ofproto.OFPMP_METER, OFPMeterStats)
@_set_msg_type(ofproto.OFPT_MULTIPART_REQUEST)
class OFPMeterStatsRequest(OFPMultipartRequest):
    """
    Meter statistics request message

    The controller uses this message to query statistics for one or more
    meters.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    flags            Zero or ``OFPMPF_REQ_MORE``
    meter_id         ID of meter to read (OFPM_ALL to all meters)
    ================ ======================================================

    Example::

        def send_meter_stats_request(self, datapath):
            ofp = datapath.ofproto
            ofp_parser = datapath.ofproto_parser

            req = ofp_parser.OFPMeterStatsRequest(datapath, 0, ofp.OFPM_ALL)
            datapath.send_msg(req)
    """
    def __init__(self, datapath, flags=0, meter_id=ofproto.OFPM_ALL,
                 type_=None):
        super(OFPMeterStatsRequest, self).__init__(datapath, flags)
        self.meter_id = meter_id

    def _serialize_stats_body(self):
        msg_pack_into(ofproto.OFP_METER_MULTIPART_REQUEST_PACK_STR,
                      self.buf,
                      ofproto.OFP_MULTIPART_REQUEST_SIZE,
                      self.meter_id)


@OFPMultipartReply.register_stats_type()
@_set_stats_type(ofproto.OFPMP_METER, OFPMeterStats)
@_set_msg_type(ofproto.OFPT_MULTIPART_REPLY)
class OFPMeterStatsReply(OFPMultipartReply):
    """
    Meter statistics reply message

    The switch responds with this message to a meter statistics request.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    body             List of ``OFPMeterStats`` instance
    ================ ======================================================

    Example::

        @set_ev_cls(ofp_event.EventOFPMeterStatsReply, MAIN_DISPATCHER)
        def meter_stats_reply_handler(self, ev):
            meters = []
            for stat in ev.msg.body:
                meters.append('meter_id=0x%08x len=%d flow_count=%d '
                              'packet_in_count=%d byte_in_count=%d '
                              'duration_sec=%d duration_nsec=%d '
                              'band_stats=%s' %
                              (stat.meter_id, stat.len, stat.flow_count,
                               stat.packet_in_count, stat.byte_in_count,
                               stat.duration_sec, stat.duration_nsec,
                               stat.band_stats))
            self.logger.debug('MeterStats: %s', meters)
    """
    def __init__(self, datapath, type_=None, **kwargs):
        super(OFPMeterStatsReply, self).__init__(datapath, **kwargs)


class OFPMeterBand(StringifyMixin):
    def __init__(self, type_, len_):
        super(OFPMeterBand, self).__init__()
        self.type = type_
        self.len = len_


class OFPMeterBandHeader(OFPMeterBand):
    _METER_BAND = {}

    @staticmethod
    def register_meter_band_type(type_, len_):
        def _register_meter_band_type(cls):
            OFPMeterBandHeader._METER_BAND[type_] = cls
            cls.cls_meter_band_type = type_
            cls.cls_meter_band_len = len_
            return cls
        return _register_meter_band_type

    def __init__(self):
        cls = self.__class__
        super(OFPMeterBandHeader, self).__init__(cls.cls_meter_band_type,
                                                 cls.cls_meter_band_len)

    @classmethod
    def parser(cls, buf, offset):
        type_, len_, _rate, _burst_size = struct.unpack_from(
            ofproto.OFP_METER_BAND_HEADER_PACK_STR, buf, offset)
        cls_ = cls._METER_BAND[type_]
        assert cls_.cls_meter_band_len == len_
        return cls_.parser(buf, offset)


@OFPMeterBandHeader.register_meter_band_type(
    ofproto.OFPMBT_DROP, ofproto.OFP_METER_BAND_DROP_SIZE)
class OFPMeterBandDrop(OFPMeterBandHeader):
    def __init__(self, rate=0, burst_size=0, type_=None, len_=None):
        super(OFPMeterBandDrop, self).__init__()
        self.rate = rate
        self.burst_size = burst_size

    def serialize(self, buf, offset):
        msg_pack_into(ofproto.OFP_METER_BAND_DROP_PACK_STR, buf, offset,
                      self.type, self.len, self.rate, self.burst_size)

    @classmethod
    def parser(cls, buf, offset):
        type_, len_, rate, burst_size = struct.unpack_from(
            ofproto.OFP_METER_BAND_DROP_PACK_STR, buf, offset)
        assert cls.cls_meter_band_type == type_
        assert cls.cls_meter_band_len == len_
        return cls(rate, burst_size)


@OFPMeterBandHeader.register_meter_band_type(
    ofproto.OFPMBT_DSCP_REMARK,
    ofproto.OFP_METER_BAND_DSCP_REMARK_SIZE)
class OFPMeterBandDscpRemark(OFPMeterBandHeader):
    def __init__(self, rate=0, burst_size=0, prec_level=0,
                 type_=None, len_=None):
        super(OFPMeterBandDscpRemark, self).__init__()
        self.rate = rate
        self.burst_size = burst_size
        self.prec_level = prec_level

    def serialize(self, buf, offset):
        msg_pack_into(ofproto.OFP_METER_BAND_DSCP_REMARK_PACK_STR, buf,
                      offset, self.type, self.len, self.rate,
                      self.burst_size, self.prec_level)

    @classmethod
    def parser(cls, buf, offset):
        type_, len_, rate, burst_size, prec_level = struct.unpack_from(
            ofproto.OFP_METER_BAND_DSCP_REMARK_PACK_STR, buf, offset)
        assert cls.cls_meter_band_type == type_
        assert cls.cls_meter_band_len == len_
        return cls(rate, burst_size, prec_level)


@OFPMeterBandHeader.register_meter_band_type(
    ofproto.OFPMBT_EXPERIMENTER,
    ofproto.OFP_METER_BAND_EXPERIMENTER_SIZE)
class OFPMeterBandExperimenter(OFPMeterBandHeader):
    def __init__(self, rate=0, burst_size=0, experimenter=None,
                 type_=None, len_=None):
        super(OFPMeterBandExperimenter, self).__init__()
        self.rate = rate
        self.burst_size = burst_size
        self.experimenter = experimenter

    def serialize(self, buf, offset):
        msg_pack_into(ofproto.OFP_METER_BAND_EXPERIMENTER_PACK_STR, buf,
                      offset, self.type, self.len, self.rate,
                      self.burst_size, self.experimenter)

    @classmethod
    def parser(cls, buf, offset):
        type_, len_, rate, burst_size, experimenter = struct.unpack_from(
            ofproto.OFP_METER_BAND_EXPERIMENTER_PACK_STR, buf, offset)
        assert cls.cls_meter_band_type == type_
        assert cls.cls_meter_band_len == len_
        return cls(rate, burst_size, experimenter)


class OFPMeterConfigStats(StringifyMixin):
    def __init__(self, flags=None, meter_id=None, bands=None, length=None):
        super(OFPMeterConfigStats, self).__init__()
        self.length = None
        self.flags = flags
        self.meter_id = meter_id
        self.bands = bands

    @classmethod
    def parser(cls, buf, offset):
        meter_config = cls()

        (meter_config.length, meter_config.flags,
         meter_config.meter_id) = struct.unpack_from(
            ofproto.OFP_METER_CONFIG_PACK_STR, buf, offset)
        offset += ofproto.OFP_METER_CONFIG_SIZE

        meter_config.bands = []
        length = ofproto.OFP_METER_CONFIG_SIZE
        while length < meter_config.length:
            band = OFPMeterBandHeader.parser(buf, offset)
            meter_config.bands.append(band)
            offset += band.len
            length += band.len

        return meter_config


@_set_stats_type(ofproto.OFPMP_METER_CONFIG, OFPMeterConfigStats)
@_set_msg_type(ofproto.OFPT_MULTIPART_REQUEST)
class OFPMeterConfigStatsRequest(OFPMultipartRequest):
    """
    Meter configuration statistics request message

    The controller uses this message to query configuration for one or more
    meters.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    flags            Zero or ``OFPMPF_REQ_MORE``
    meter_id         ID of meter to read (OFPM_ALL to all meters)
    ================ ======================================================

    Example::

        def send_meter_config_stats_request(self, datapath):
            ofp = datapath.ofproto
            ofp_parser = datapath.ofproto_parser

            req = ofp_parser.OFPMeterConfigStatsRequest(datapath, 0,
                                                        ofp.OFPM_ALL)
            datapath.send_msg(req)
    """
    def __init__(self, datapath, flags=0, meter_id=ofproto.OFPM_ALL,
                 type_=None):
        super(OFPMeterConfigStatsRequest, self).__init__(datapath, flags)
        self.meter_id = meter_id

    def _serialize_stats_body(self):
        msg_pack_into(ofproto.OFP_METER_MULTIPART_REQUEST_PACK_STR,
                      self.buf,
                      ofproto.OFP_MULTIPART_REQUEST_SIZE,
                      self.meter_id)


@OFPMultipartReply.register_stats_type()
@_set_stats_type(ofproto.OFPMP_METER_CONFIG, OFPMeterConfigStats)
@_set_msg_type(ofproto.OFPT_MULTIPART_REPLY)
class OFPMeterConfigStatsReply(OFPMultipartReply):
    """
    Meter configuration statistics reply message

    The switch responds with this message to a meter configuration
    statistics request.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    body             List of ``OFPMeterConfigStats`` instance
    ================ ======================================================

    Example::

        @set_ev_cls(ofp_event.EventOFPMeterConfigStatsReply, MAIN_DISPATCHER)
        def meter_config_stats_reply_handler(self, ev):
            configs = []
            for stat in ev.msg.body:
                configs.append('length=%d flags=0x%04x meter_id=0x%08x '
                               'bands=%s' %
                               (stat.length, stat.flags, stat.meter_id,
                                stat.bands))
            self.logger.debug('MeterConfigStats: %s', configs)
    """
    def __init__(self, datapath, type_=None, **kwargs):
        super(OFPMeterConfigStatsReply, self).__init__(datapath, **kwargs)


class OFPMeterFeaturesStats(ofproto_parser.namedtuple('OFPMeterFeaturesStats',
                            ('max_meter', 'band_types', 'capabilities',
                             'max_band', 'max_color'))):
    @classmethod
    def parser(cls, buf, offset):
        meter_features = struct.unpack_from(
            ofproto.OFP_METER_FEATURES_PACK_STR, buf, offset)
        stats = cls(*meter_features)
        stats.length = ofproto.OFP_METER_FEATURES_SIZE
        return stats


@_set_stats_type(ofproto.OFPMP_METER_FEATURES, OFPMeterFeaturesStats)
@_set_msg_type(ofproto.OFPT_MULTIPART_REQUEST)
class OFPMeterFeaturesStatsRequest(OFPMultipartRequest):
    """
    Meter features statistics request message

    The controller uses this message to query the set of features of the
    metering subsystem.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    flags            Zero or ``OFPMPF_REQ_MORE``
    ================ ======================================================

    Example::

        def send_meter_features_stats_request(self, datapath):
            ofp_parser = datapath.ofproto_parser

            req = ofp_parser.OFPMeterFeaturesStatsRequest(datapath, 0)
            datapath.send_msg(req)
    """
    def __init__(self, datapath, flags=0, type_=None):
        super(OFPMeterFeaturesStatsRequest, self).__init__(datapath, flags)


@OFPMultipartReply.register_stats_type()
@_set_stats_type(ofproto.OFPMP_METER_FEATURES, OFPMeterFeaturesStats)
@_set_msg_type(ofproto.OFPT_MULTIPART_REPLY)
class OFPMeterFeaturesStatsReply(OFPMultipartReply):
    """
    Meter features statistics reply message

    The switch responds with this message to a meter features statistics
    request.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    body             List of ``OFPMeterFeaturesStats`` instance
    ================ ======================================================

    Example::

        @set_ev_cls(ofp_event.EventOFPMeterFeaturesStatsReply, MAIN_DISPATCHER)
        def meter_features_stats_reply_handler(self, ev):
            features = []
            for stat in ev.msg.body:
                features.append('max_meter=%d band_types=0x%08x '
                                'capabilities=0x%08x max_band=%d '
                                'max_color=%d' %
                                (stat.max_meter, stat.band_types,
                                 stat.capabilities, stat.max_band,
                                 stat.max_color))
            self.logger.debug('MeterFeaturesStats: %s', configs)
    """
    def __init__(self, datapath, type_=None, **kwargs):
        super(OFPMeterFeaturesStatsReply, self).__init__(datapath, **kwargs)


class OFPTableFeaturesStats(StringifyMixin):

    _TYPE = {
        'utf-8': [
            # OF spec is unclear about the encoding of name.
            # we assumes UTF-8.
            'name',
        ]
    }

    def __init__(self, table_id=None, name=None, metadata_match=None,
                 metadata_write=None, config=None, max_entries=None,
                 properties=None, length=None):
        super(OFPTableFeaturesStats, self).__init__()
        self.length = None
        self.table_id = table_id
        self.name = name
        self.metadata_match = metadata_match
        self.metadata_write = metadata_write
        self.config = config
        self.max_entries = max_entries
        self.properties = properties

    @classmethod
    def parser(cls, buf, offset):
        table_features = cls()
        (table_features.length, table_features.table_id,
         name, table_features.metadata_match,
         table_features.metadata_write, table_features.config,
         table_features.max_entries
         ) = struct.unpack_from(ofproto.OFP_TABLE_FEATURES_PACK_STR,
                                buf, offset)
        table_features.name = name.rstrip('\0')

        props = []
        rest = buf[offset + ofproto.OFP_TABLE_FEATURES_SIZE:
                   offset + table_features.length]
        while rest:
            p, rest = OFPTableFeatureProp.parse(rest)
            props.append(p)
        table_features.properties = props

        return table_features

    def serialize(self):
        # fixup
        bin_props = bytearray()
        for p in self.properties:
            bin_props += p.serialize()
        self.length = ofproto.OFP_TABLE_FEATURES_SIZE + len(bin_props)

        buf = bytearray()
        msg_pack_into(ofproto.OFP_TABLE_FEATURES_PACK_STR, buf, 0,
                      self.length, self.table_id, self.name,
                      self.metadata_match, self.metadata_write,
                      self.config, self.max_entries)
        return buf + bin_props


class OFPTableFeatureProp(StringifyMixin):
    _PACK_STR = '!HH'  # type, length
    _TYPES = {}  # OFPTFPT_ -> class

    def __init__(self, type_, length=None):
        self.type = type_
        self.length = length

    @classmethod
    def register_type(cls, type_):
        def _register_type(subcls):
            cls._TYPES[type_] = subcls
            return subcls
        return _register_type

    @classmethod
    def parse(cls, buf):
        (type_, length,) = struct.unpack_from(cls._PACK_STR, buffer(buf), 0)
        bin_prop = buf[struct.calcsize(cls._PACK_STR):length]
        rest = buf[utils.round_up(length, 8):]
        try:
            subcls = cls._TYPES[type_]
        except KeyError:
            subcls = OFPTableFeaturePropUnknown
        kwargs = subcls._parse_prop(bin_prop)
        kwargs['type_'] = type_
        kwargs['length'] = length
        return subcls(**kwargs), rest

    def serialize(self):
        # fixup
        bin_prop = self._serialize_prop()
        self.length = struct.calcsize(self._PACK_STR) + len(bin_prop)

        buf = bytearray()
        msg_pack_into(self._PACK_STR, buf, 0, self.type, self.length)
        pad_len = utils.round_up(self.length, 8) - self.length
        return buf + bin_prop + pad_len * '\0'


class OFPTableFeaturePropUnknown(OFPTableFeatureProp):
    def __init__(self, type_, length=None, data=None):
        super(OFPTableFeaturePropUnknown, self).__init__(type_, length)
        self.data = data

    @classmethod
    def _parse_prop(cls, buf):
        return {'data': buf}

    def _serialize_prop(self):
        return self.data


# Implementation note: While OpenFlow 1.3.2 shares the same ofp_instruction
# for flow_mod and table_features, we have separate classes.  We named this
# class to match with OpenFlow 1.4's name.  (ofp_instruction_id)
class OFPInstructionId(StringifyMixin):
    _PACK_STR = '!HH'  # type, len

    def __init__(self, type_, len_=None):
        self.type = type_
        self.len = len_
        # XXX experimenter

    @classmethod
    def parse(cls, buf):
        (type_, len_,) = struct.unpack_from(cls._PACK_STR, buffer(buf), 0)
        rest = buf[len_:]
        return cls(type_=type_, len_=len_), rest

    def serialize(self):
        # fixup
        self.len = struct.calcsize(self._PACK_STR)

        buf = bytearray()
        msg_pack_into(self._PACK_STR, buf, 0, self.type, self.len)
        return buf


@OFPTableFeatureProp.register_type(ofproto.OFPTFPT_INSTRUCTIONS)
@OFPTableFeatureProp.register_type(ofproto.OFPTFPT_INSTRUCTIONS_MISS)
class OFPTableFeaturePropInstructions(OFPTableFeatureProp):
    def __init__(self, type_, instruction_ids=[], length=None):
        super(OFPTableFeaturePropInstructions, self).__init__(type_, length)
        self.instruction_ids = instruction_ids

    @classmethod
    def _parse_prop(cls, buf):
        rest = buf
        ids = []
        while rest:
            i, rest = OFPInstructionId.parse(rest)
            ids.append(i)
        return {
            'instruction_ids': ids,
        }

    def _serialize_prop(self):
        bin_ids = bytearray()
        for i in self.instruction_ids:
            bin_ids += i.serialize()
        return bin_ids


@OFPTableFeatureProp.register_type(ofproto.OFPTFPT_NEXT_TABLES)
@OFPTableFeatureProp.register_type(ofproto.OFPTFPT_NEXT_TABLES_MISS)
class OFPTableFeaturePropNextTables(OFPTableFeatureProp):
    _TABLE_ID_PACK_STR = '!B'

    def __init__(self, type_, table_ids=[], length=None):
        super(OFPTableFeaturePropNextTables, self).__init__(type_, length)
        self.table_ids = table_ids

    @classmethod
    def _parse_prop(cls, buf):
        rest = buf
        ids = []
        while rest:
            (i,) = struct.unpack_from(cls._TABLE_ID_PACK_STR, buffer(rest), 0)
            rest = rest[struct.calcsize(cls._TABLE_ID_PACK_STR):]
            ids.append(i)
        return {
            'table_ids': ids,
        }

    def _serialize_prop(self):
        bin_ids = bytearray()
        for i in self.table_ids:
            bin_id = bytearray()
            msg_pack_into(self._TABLE_ID_PACK_STR, bin_id, 0, i)
            bin_ids += bin_id
        return bin_ids


# Implementation note: While OpenFlow 1.3.2 shares the same ofp_action_header
# for flow_mod and table_features, we have separate classes.  We named this
# class to match with OpenFlow 1.4's name.  (ofp_action_id)
class OFPActionId(StringifyMixin):
    # XXX
    # ofp_action_header should have trailing pad bytes.
    # however, i guess it's a specification bug as:
    #  - the spec explicitly says non-experimenter actions are 4 bytes
    #  - linc/of_protocol doesn't use them
    #  - OpenFlow 1.4 changed to use a separate structure
    _PACK_STR = '!HH'  # type, len

    def __init__(self, type_, len_=None):
        self.type = type_
        self.len = len_
        # XXX experimenter

    @classmethod
    def parse(cls, buf):
        (type_, len_,) = struct.unpack_from(cls._PACK_STR, buffer(buf), 0)
        rest = buf[len_:]
        return cls(type_=type_, len_=len_), rest

    def serialize(self):
        # fixup
        self.len = struct.calcsize(self._PACK_STR)

        buf = bytearray()
        msg_pack_into(self._PACK_STR, buf, 0, self.type, self.len)
        return buf


@OFPTableFeatureProp.register_type(ofproto.OFPTFPT_WRITE_ACTIONS)
@OFPTableFeatureProp.register_type(ofproto.OFPTFPT_WRITE_ACTIONS_MISS)
@OFPTableFeatureProp.register_type(ofproto.OFPTFPT_APPLY_ACTIONS)
@OFPTableFeatureProp.register_type(ofproto.OFPTFPT_APPLY_ACTIONS_MISS)
class OFPTableFeaturePropActions(OFPTableFeatureProp):
    def __init__(self, type_, action_ids=[], length=None):
        super(OFPTableFeaturePropActions, self).__init__(type_, length)
        self.action_ids = action_ids

    @classmethod
    def _parse_prop(cls, buf):
        rest = buf
        ids = []
        while rest:
            i, rest = OFPActionId.parse(rest)
            ids.append(i)
        return {
            'action_ids': ids,
        }

    def _serialize_prop(self):
        bin_ids = bytearray()
        for i in self.action_ids:
            bin_ids += i.serialize()
        return bin_ids


# Implementation note: OFPOxmId is specific to this implementation.
# It does not have a corresponding structure in the specification.
# (the specification uses plain uint32_t for them.)
#
# i have taken a look at some of software switch implementations
# but they all look broken or incomplete.  according to the spec,
# oxm_hasmask should be 1 if a switch supports masking for the type.
# the right value for oxm_length is not clear from the spec.
# update: OpenFlow 1.3.3 "clarified" that oxm_length here is the payload
# length.  it's still unclear if it should be doubled for hasmask or not,
# though.
#   ofsoftswitch13
#     oxm_hasmask  always 0
#     oxm_length   same as ofp_match etc (as without mask)
#   linc/of_protocol
#     oxm_hasmask  always 0
#     oxm_length   always 0
#   ovs:
#     table-feature is not implemented
class OFPOxmId(StringifyMixin):
    _PACK_STR = '!I'  # oxm header

    _TYPE = {
        'ascii': [
            'type',
        ],
    }

    def __init__(self, type_, hasmask=False, length=None):
        self.type = type_
        self.hasmask = hasmask
        self.length = length
        # XXX experimenter

    @classmethod
    def parse(cls, buf):
        (oxm,) = struct.unpack_from(cls._PACK_STR, buffer(buf), 0)
        (type_, _v) = ofproto.oxm_to_user(oxm >> 9, None, None)
        hasmask = ofproto.oxm_tlv_header_extract_hasmask(oxm)
        length = oxm & 0xff  # XXX see the comment on OFPOxmId
        rest = buf[4:]  # XXX see the comment on OFPOxmId
        return cls(type_=type_, hasmask=hasmask, length=length), rest

    def serialize(self):
        # fixup
        self.length = 0  # XXX see the comment on OFPOxmId

        (n, _v, _m) = ofproto.oxm_from_user(self.type, None)
        oxm = (n << 9) | (self.hasmask << 8) | self.length
        buf = bytearray()
        msg_pack_into(self._PACK_STR, buf, 0, oxm)
        return buf


@OFPTableFeatureProp.register_type(ofproto.OFPTFPT_MATCH)
@OFPTableFeatureProp.register_type(ofproto.OFPTFPT_WILDCARDS)
@OFPTableFeatureProp.register_type(ofproto.OFPTFPT_WRITE_SETFIELD)
@OFPTableFeatureProp.register_type(ofproto.OFPTFPT_WRITE_SETFIELD_MISS)
@OFPTableFeatureProp.register_type(ofproto.OFPTFPT_APPLY_SETFIELD)
@OFPTableFeatureProp.register_type(ofproto.OFPTFPT_APPLY_SETFIELD_MISS)
class OFPTableFeaturePropOxm(OFPTableFeatureProp):
    def __init__(self, type_, oxm_ids=[], length=None):
        super(OFPTableFeaturePropOxm, self).__init__(type_, length)
        self.oxm_ids = oxm_ids

    @classmethod
    def _parse_prop(cls, buf):
        rest = buf
        ids = []
        while rest:
            i, rest = OFPOxmId.parse(rest)
            ids.append(i)
        return {
            'oxm_ids': ids,
        }

    def _serialize_prop(self):
        bin_ids = bytearray()
        for i in self.oxm_ids:
            bin_ids += i.serialize()
        return bin_ids


@OFPTableFeatureProp.register_type(ofproto.OFPTFPT_EXPERIMENTER)
@OFPTableFeatureProp.register_type(ofproto.OFPTFPT_EXPERIMENTER_MISS)
class OFPTableFeaturePropExperimenter(OFPTableFeatureProp):
    _DATA_ELEMENT_PACK_STR = '!I'
    _BODY_PACK_STR = '!II'

    def __init__(self, type_, experimenter=None, exp_type=None,
                 data=None, length=None):
        self.type = type_
        self.length = length
        self.experimenter = experimenter
        self.exp_type = exp_type
        self.data = data

    @classmethod
    def _parse_prop(cls, buf):
        (experimenter, exp_type) = struct.unpack_from(cls._BODY_PACK_STR,
                                                      buf, 0)

        # Parse trailing data, a list of 4-byte words
        length = len(buf)
        data = []
        pack_size = struct.calcsize(cls._DATA_ELEMENT_PACK_STR)
        offset = struct.calcsize(cls._BODY_PACK_STR)
        while offset < length:
            (word,) = struct.unpack_from(cls._DATA_ELEMENT_PACK_STR,
                                         buf, offset)
            data.append(word)
            offset += pack_size

        return {
            'experimenter': experimenter,
            'exp_type': exp_type,
            'data': data,
        }

    def _serialize_prop(self):
        # experimenter, exp_type
        buf = bytearray()
        msg_pack_into(self._BODY_PACK_STR, buf, 0, self.experimenter,
                      self.exp_type)

        # data
        if len(self.data):
            ofproto_parser.msg_pack_into('!%dI' % len(self.data),
                                         buf, len(buf), *self.data)

        return buf


@_set_stats_type(ofproto.OFPMP_TABLE_FEATURES, OFPTableFeaturesStats)
@_set_msg_type(ofproto.OFPT_MULTIPART_REQUEST)
class OFPTableFeaturesStatsRequest(OFPMultipartRequest):
    """
    Table features statistics request message

    The controller uses this message to query table features.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    body             List of ``OFPTableFeaturesStats`` instances.
                     The default is [].
    ================ ======================================================
    """
    def __init__(self, datapath, flags=0,
                 body=[],
                 type_=None):
        super(OFPTableFeaturesStatsRequest, self).__init__(datapath, flags)
        self.body = body

    def _serialize_stats_body(self):
        bin_body = bytearray()
        for p in self.body:
            bin_body += p.serialize()
        self.buf += bin_body


@OFPMultipartReply.register_stats_type()
@_set_stats_type(ofproto.OFPMP_TABLE_FEATURES, OFPTableFeaturesStats)
@_set_msg_type(ofproto.OFPT_MULTIPART_REPLY)
class OFPTableFeaturesStatsReply(OFPMultipartReply):
    """
    Table features statistics reply message

    The switch responds with this message to a table features statistics
    request.

    This implmentation is still incomplete.
    Namely, this implementation does not parse ``properties`` list and
    always reports it empty.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    body             List of ``OFPTableFeaturesStats`` instance
    ================ ======================================================
    """
    def __init__(self, datapath, type_=None, **kwargs):
        super(OFPTableFeaturesStatsReply, self).__init__(datapath, **kwargs)


@_set_stats_type(ofproto.OFPMP_PORT_DESC, OFPPort)
@_set_msg_type(ofproto.OFPT_MULTIPART_REQUEST)
class OFPPortDescStatsRequest(OFPMultipartRequest):
    """
    Port description request message

    The controller uses this message to query description of all the ports.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    flags            Zero or ``OFPMPF_REQ_MORE``
    ================ ======================================================

    Example::

        def send_port_desc_stats_request(self, datapath):
            ofp_parser = datapath.ofproto_parser

            req = ofp_parser.OFPPortDescStatsRequest(datapath, 0)
            datapath.send_msg(req)
    """
    def __init__(self, datapath, flags=0, type_=None):
        super(OFPPortDescStatsRequest, self).__init__(datapath, flags)


@OFPMultipartReply.register_stats_type()
@_set_stats_type(ofproto.OFPMP_PORT_DESC, OFPPort)
@_set_msg_type(ofproto.OFPT_MULTIPART_REPLY)
class OFPPortDescStatsReply(OFPMultipartReply):
    """
    Port description reply message

    The switch responds with this message to a port description request.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    body             List of ``OFPPortDescStats`` instance
    ================ ======================================================

    Example::

        @set_ev_cls(ofp_event.EventOFPPortDescStatsReply, MAIN_DISPATCHER)
        def port_desc_stats_reply_handler(self, ev):
            ports = []
            for p in ev.msg.body:
                ports.append('port_no=%d hw_addr=%s name=%s config=0x%08x '
                             'state=0x%08x curr=0x%08x advertised=0x%08x '
                             'supported=0x%08x peer=0x%08x curr_speed=%d '
                             'max_speed=%d' %
                             (p.port_no, p.hw_addr,
                              p.name, p.config,
                              p.state, p.curr, p.advertised,
                              p.supported, p.peer, p.curr_speed,
                              p.max_speed))
            self.logger.debug('OFPPortDescStatsReply received: %s', ports)
    """
    def __init__(self, datapath, type_=None, **kwargs):
        super(OFPPortDescStatsReply, self).__init__(datapath, **kwargs)


class OFPExperimenterMultipart(ofproto_parser.namedtuple(
                               'OFPExperimenterMultipart',
                               ('experimenter', 'exp_type', 'data'))):
    """
    The body of OFPExperimenterStatsReply multipart messages.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    experimenter     Experimenter ID
    exp_type         Experimenter defined
    data             Experimenter defined additional data
    ================ ======================================================
    """

    @classmethod
    def parser(cls, buf, offset):
        args = struct.unpack_from(
            ofproto.OFP_EXPERIMENTER_MULTIPART_HEADER_PACK_STR, buf,
            offset)
        args = list(args)
        args.append(buf[offset +
                        ofproto.OFP_EXPERIMENTER_MULTIPART_HEADER_SIZE:])
        stats = cls(*args)
        stats.length = ofproto.OFP_METER_FEATURES_SIZE
        return stats

    def serialize(self):
        buf = bytearray()
        msg_pack_into(ofproto.OFP_EXPERIMENTER_MULTIPART_HEADER_PACK_STR,
                      buf, 0,
                      self.experimenter, self.exp_type)
        return buf + self.data


class OFPExperimenterStatsRequestBase(OFPMultipartRequest):
    def __init__(self, datapath, flags,
                 experimenter, exp_type,
                 type_=None):
        super(OFPExperimenterStatsRequestBase, self).__init__(datapath, flags)
        self.experimenter = experimenter
        self.exp_type = exp_type


@_set_stats_type(ofproto.OFPMP_EXPERIMENTER, OFPExperimenterMultipart)
@_set_msg_type(ofproto.OFPT_MULTIPART_REQUEST)
class OFPExperimenterStatsRequest(OFPExperimenterStatsRequestBase):
    """
    Experimenter multipart request message

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    flags            Zero or ``OFPMPF_REQ_MORE``
    experimenter     Experimenter ID
    exp_type         Experimenter defined
    data             Experimenter defined additional data
    ================ ======================================================
    """
    def __init__(self, datapath, flags,
                 experimenter, exp_type, data,
                 type_=None):
        super(OFPExperimenterStatsRequest, self).__init__(datapath, flags,
                                                          experimenter,
                                                          exp_type, type_)
        self.data = data

    def _serialize_stats_body(self):
        body = OFPExperimenterMultipart(experimenter=self.experimenter,
                                        exp_type=self.exp_type,
                                        data=self.data)
        self.buf += body.serialize()


# NOTE: we use OFPMatch while on-wire does not ofp_match.
# (OF1.4 version uses ofp_match.)
class ONFFlowMonitorRequest(StringifyMixin):
    def __init__(self, id_, flags,
                 match=OFPMatch(),
                 out_port=ofproto.OFPP_ANY,
                 table_id=ofproto.OFPTT_ALL,
                 match_len=None):
        self.id = id_
        self.flags = flags
        self.match_len = match_len
        self.out_port = out_port
        self.table_id = table_id
        self.match = match

    def serialize(self):
        # fixup
        match = self.match
        bin_match = bytearray()
        ofp_match_len = match.serialize(bin_match, 0)
        assert len(bin_match) == ofp_match_len
        match_len = match.length
        match_hdr_len = ofproto.OFP_MATCH_SIZE - 4  # exclude pad[4]
        # strip ofp_match header and trailing padding
        bin_match = bytes(bin_match)[match_hdr_len:match_len]
        self.match_len = len(bin_match)

        buf = bytearray()
        msg_pack_into(ofproto.ONF_FLOW_MONITOR_REQUEST_PACK_STR,
                      buf, 0,
                      self.id, self.flags, self.match_len,
                      self.out_port, self.table_id)
        buf += bin_match
        pad_len = utils.round_up(self.match_len, 8) - self.match_len
        buf += pad_len * '\0'
        return buf


@_set_stats_type(ofproto.OFPMP_EXPERIMENTER, OFPExperimenterMultipart)
@_set_msg_type(ofproto.OFPT_MULTIPART_REQUEST)
class ONFFlowMonitorStatsRequest(OFPExperimenterStatsRequestBase):
    """
    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    flags            Zero or ``OFPMPF_REQ_MORE``
    body             List of ONFFlowMonitorRequest instances
    ================ ======================================================
    """
    def __init__(self, datapath, flags, body=[],
                 type_=None, experimenter=None, exp_type=None):
        super(ONFFlowMonitorStatsRequest,
              self).__init__(datapath, flags,
                             experimenter=ofproto_common.ONF_EXPERIMENTER_ID,
                             exp_type=ofproto.ONFMP_FLOW_MONITOR)
        self.body = body

    def _serialize_stats_body(self):
        data = bytearray()
        for i in self.body:
            data += i.serialize()
        body = OFPExperimenterMultipart(experimenter=self.experimenter,
                                        exp_type=self.exp_type,
                                        data=data)
        self.buf += body.serialize()


@OFPMultipartReply.register_stats_type(body_single_struct=True)
@_set_stats_type(ofproto.OFPMP_EXPERIMENTER, OFPExperimenterMultipart)
@_set_msg_type(ofproto.OFPT_MULTIPART_REPLY)
class OFPExperimenterStatsReply(OFPMultipartReply):
    """
    Experimenter multipart reply message

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    body             An ``OFPExperimenterMultipart`` instance
    ================ ======================================================
    """
    def __init__(self, datapath, type_=None, **kwargs):
        super(OFPExperimenterStatsReply, self).__init__(datapath, **kwargs)


@_set_msg_type(ofproto.OFPT_BARRIER_REQUEST)
class OFPBarrierRequest(MsgBase):
    """
    Barrier request message

    The controller sends this message to ensure message dependencies have
    been met or receive notifications for completed operations.

    Example::

        def send_barrier_request(self, datapath):
            ofp_parser = datapath.ofproto_parser

            req = ofp_parser.OFPBarrierRequest(datapath)
            datapath.send_msg(req)
    """
    def __init__(self, datapath):
        super(OFPBarrierRequest, self).__init__(datapath)


@_register_parser
@_set_msg_type(ofproto.OFPT_BARRIER_REPLY)
class OFPBarrierReply(MsgBase):
    """
    Barrier reply message

    The switch responds with this message to a barrier request.

    Example::

        @set_ev_cls(ofp_event.EventOFPBarrierReply, MAIN_DISPATCHER)
        def barrier_reply_handler(self, ev):
            self.logger.debug('OFPBarrierReply received')
    """
    def __init__(self, datapath):
        super(OFPBarrierReply, self).__init__(datapath)


@_set_msg_type(ofproto.OFPT_QUEUE_GET_CONFIG_REQUEST)
class OFPQueueGetConfigRequest(MsgBase):
    """
    Queue configuration request message

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    port             Port to be queried (OFPP_ANY to all configured queues)
    ================ ======================================================

    Example::

        def send_queue_get_config_request(self, datapath):
            ofp = datapath.ofproto
            ofp_parser = datapath.ofproto_parser

            req = ofp_parser.OFPQueueGetConfigRequest(datapath, ofp.OFPP_ANY)
            datapath.send_msg(req)
    """
    def __init__(self, datapath, port):
        super(OFPQueueGetConfigRequest, self).__init__(datapath)
        self.port = port

    def _serialize_body(self):
        msg_pack_into(ofproto.OFP_QUEUE_GET_CONFIG_REQUEST_PACK_STR,
                      self.buf, ofproto.OFP_HEADER_SIZE, self.port)


class OFPQueuePropHeader(StringifyMixin):
    def __init__(self, property_, len_):
        self.property = property_
        self.len = len_

    def serialize(self, buf, offset):
        msg_pack_into(ofproto.OFP_QUEUE_PROP_HEADER_PACK_STR,
                      buf, offset, self.property, self.len)


class OFPQueueProp(OFPQueuePropHeader):
    _QUEUE_PROP_PROPERTIES = {}

    @staticmethod
    def register_queue_property(property_, len_):
        def _register_queue_property(cls):
            cls.cls_property = property_
            cls.cls_len = len_
            OFPQueueProp._QUEUE_PROP_PROPERTIES[cls.cls_property] = cls
            return cls
        return _register_queue_property

    def __init__(self):
        cls = self.__class__
        super(OFPQueueProp, self).__init__(cls.cls_property,
                                           cls.cls_len)

    @classmethod
    def parser(cls, buf, offset):
        (property_, len_) = struct.unpack_from(
            ofproto.OFP_QUEUE_PROP_HEADER_PACK_STR,
            buf, offset)
        cls_ = cls._QUEUE_PROP_PROPERTIES.get(property_)
        offset += ofproto.OFP_QUEUE_PROP_HEADER_SIZE
        return cls_.parser(buf, offset)


@OFPQueueProp.register_queue_property(
    ofproto.OFPQT_MIN_RATE,
    ofproto.OFP_QUEUE_PROP_MIN_RATE_SIZE)
class OFPQueuePropMinRate(OFPQueueProp):
    def __init__(self, rate, property_=None, len_=None):
        super(OFPQueuePropMinRate, self).__init__()
        self.rate = rate

    @classmethod
    def parser(cls, buf, offset):
        (rate,) = struct.unpack_from(
            ofproto.OFP_QUEUE_PROP_MIN_RATE_PACK_STR, buf, offset)
        return cls(rate)


@OFPQueueProp.register_queue_property(
    ofproto.OFPQT_MAX_RATE,
    ofproto.OFP_QUEUE_PROP_MAX_RATE_SIZE)
class OFPQueuePropMaxRate(OFPQueueProp):
    def __init__(self, rate, property_=None, len_=None):
        super(OFPQueuePropMaxRate, self).__init__()
        self.rate = rate

    @classmethod
    def parser(cls, buf, offset):
        (rate,) = struct.unpack_from(
            ofproto.OFP_QUEUE_PROP_MAX_RATE_PACK_STR, buf, offset)
        return cls(rate)


# TODO: add ofp_queue_prop_experimenter


class OFPPacketQueue(StringifyMixin):
    def __init__(self, queue_id, port, properties, len_=None):
        super(OFPPacketQueue, self).__init__()
        self.queue_id = queue_id
        self.port = port
        self.len = len_
        self.properties = properties

    @classmethod
    def parser(cls, buf, offset):
        (queue_id, port, len_) = struct.unpack_from(
            ofproto.OFP_PACKET_QUEUE_PACK_STR, buf, offset)
        length = ofproto.OFP_PACKET_QUEUE_SIZE
        offset += ofproto.OFP_PACKET_QUEUE_SIZE
        properties = []
        while length < len_:
            queue_prop = OFPQueueProp.parser(buf, offset)
            properties.append(queue_prop)
            offset += queue_prop.len
            length += queue_prop.len
        o = cls(queue_id, port, properties)
        o.len = len_
        return o


@_register_parser
@_set_msg_type(ofproto.OFPT_QUEUE_GET_CONFIG_REPLY)
class OFPQueueGetConfigReply(MsgBase):
    """
    Queue configuration reply message

    The switch responds with this message to a queue configuration request.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    queues           list of ``OFPPacketQueue`` instance
    port             Port which was queried
    ================ ======================================================

    Example::

        @set_ev_cls(ofp_event.EventOFPQueueGetConfigReply, MAIN_DISPATCHER)
        def queue_get_config_reply_handler(self, ev):
            msg = ev.msg

            self.logger.debug('OFPQueueGetConfigReply received: '
                              'port=%s queues=%s',
                              msg.port, msg.queues)
    """
    def __init__(self, datapath, queues=None, port=None):
        super(OFPQueueGetConfigReply, self).__init__(datapath)
        self.queues = queues
        self.port = port

    @classmethod
    def parser(cls, datapath, version, msg_type, msg_len, xid, buf):
        msg = super(OFPQueueGetConfigReply, cls).parser(datapath, version,
                                                        msg_type,
                                                        msg_len, xid, buf)
        (msg.port,) = struct.unpack_from(
            ofproto.OFP_QUEUE_GET_CONFIG_REPLY_PACK_STR, msg.buf,
            ofproto.OFP_HEADER_SIZE)

        msg.queues = []
        offset = ofproto.OFP_QUEUE_GET_CONFIG_REPLY_SIZE
        while offset < msg_len:
            queue = OFPPacketQueue.parser(msg.buf, offset)
            msg.queues.append(queue)
            offset += queue.len

        return msg


@_set_msg_type(ofproto.OFPT_ROLE_REQUEST)
class OFPRoleRequest(MsgBase):
    """
    Role request message

    The controller uses this message to change its role.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    role             One of the following values.

                     | OFPCR_ROLE_NOCHANGE
                     | OFPCR_ROLE_EQUAL
                     | OFPCR_ROLE_MASTER
                     | OFPCR_ROLE_SLAVE
    generation_id    Master Election Generation ID
    ================ ======================================================

    Example::

        def send_role_request(self, datapath):
            ofp = datapath.ofproto
            ofp_parser = datapath.ofproto_parser

            req = ofp_parser.OFPRoleRequest(datapath, ofp.OFPCR_ROLE_EQUAL, 0)
            datapath.send_msg(req)
    """
    def __init__(self, datapath, role=None, generation_id=None):
        super(OFPRoleRequest, self).__init__(datapath)
        self.role = role
        self.generation_id = generation_id

    def _serialize_body(self):
        assert self.role is not None
        assert self.generation_id is not None
        msg_pack_into(ofproto.OFP_ROLE_REQUEST_PACK_STR,
                      self.buf, ofproto.OFP_HEADER_SIZE,
                      self.role, self.generation_id)


@_register_parser
@_set_msg_type(ofproto.OFPT_ROLE_REPLY)
class OFPRoleReply(MsgBase):
    """
    Role reply message

    The switch responds with this message to a role request.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    role             One of the following values.

                     | OFPCR_ROLE_NOCHANGE
                     | OFPCR_ROLE_EQUAL
                     | OFPCR_ROLE_MASTER
                     | OFPCR_ROLE_SLAVE
    generation_id    Master Election Generation ID
    ================ ======================================================

    Example::

        @set_ev_cls(ofp_event.EventOFPRoleReply, MAIN_DISPATCHER)
        def role_reply_handler(self, ev):
            msg = ev.msg
            ofp = dp.ofproto

            if msg.role == ofp.OFPCR_ROLE_NOCHANGE:
                role = 'NOCHANGE'
            elif msg.role == ofp.OFPCR_ROLE_EQUAL:
                role = 'EQUAL'
            elif msg.role == ofp.OFPCR_ROLE_MASTER:
                role = 'MASTER'
            elif msg.role == ofp.OFPCR_ROLE_SLAVE:
                role = 'SLAVE'
            else:
                role = 'unknown'

            self.logger.debug('OFPRoleReply received: '
                              'role=%s generation_id=%d',
                              role, msg.generation_id)
    """
    def __init__(self, datapath, role=None, generation_id=None):
        super(OFPRoleReply, self).__init__(datapath)
        self.role = role
        self.generation_id = generation_id

    @classmethod
    def parser(cls, datapath, version, msg_type, msg_len, xid, buf):
        msg = super(OFPRoleReply, cls).parser(datapath, version,
                                              msg_type, msg_len, xid,
                                              buf)
        (msg.role, msg.generation_id) = struct.unpack_from(
            ofproto.OFP_ROLE_REQUEST_PACK_STR, msg.buf,
            ofproto.OFP_HEADER_SIZE)
        return msg


@_set_msg_type(ofproto.OFPT_GET_ASYNC_REQUEST)
class OFPGetAsyncRequest(MsgBase):
    """
    Get asynchronous configuration request message

    The controller uses this message to query the asynchronous message.

    Example::

        def send_get_async_request(self, datapath):
            ofp_parser = datapath.ofproto_parser

            req = ofp_parser.OFPGetAsyncRequest(datapath)
            datapath.send_msg(req)
    """
    def __init__(self, datapath):
        super(OFPGetAsyncRequest, self).__init__(datapath)


@_register_parser
@_set_msg_type(ofproto.OFPT_GET_ASYNC_REPLY)
class OFPGetAsyncReply(MsgBase):
    """
    Get asynchronous configuration reply message

    The switch responds with this message to a get asynchronous configuration
    request.

    ================== ====================================================
    Attribute          Description
    ================== ====================================================
    packet_in_mask     2-element array: element 0, when the controller has a
                       OFPCR_ROLE_EQUAL or OFPCR_ROLE_MASTER role. element 1,
                       OFPCR_ROLE_SLAVE role controller.
                       Bitmasks of following values.

                       | OFPR_NO_MATCH
                       | OFPR_ACTION
                       | OFPR_INVALID_TTL
    port_status_mask   2-element array.
                       Bitmasks of following values.

                       | OFPPR_ADD
                       | OFPPR_DELETE
                       | OFPPR_MODIFY
    flow_removed_mask  2-element array.
                       Bitmasks of following values.

                       | OFPRR_IDLE_TIMEOUT
                       | OFPRR_HARD_TIMEOUT
                       | OFPRR_DELETE
                       | OFPRR_GROUP_DELETE
    ================== ====================================================

    Example::

        @set_ev_cls(ofp_event.EventOFPGetAsyncReply, MAIN_DISPATCHER)
        def get_async_reply_handler(self, ev):
            msg = ev.msg

            self.logger.debug('OFPGetAsyncReply received: '
                              'packet_in_mask=0x%08x:0x%08x '
                              'port_status_mask=0x%08x:0x%08x '
                              'flow_removed_mask=0x%08x:0x%08x',
                              msg.packet_in_mask[0],
                              msg.packet_in_mask[1],
                              msg.port_status_mask[0],
                              msg.port_status_mask[1],
                              msg.flow_removed_mask[0],
                              msg.flow_removed_mask[1])
    """
    def __init__(self, datapath, packet_in_mask=None, port_status_mask=None,
                 flow_removed_mask=None):
        super(OFPGetAsyncReply, self).__init__(datapath)
        self.packet_in_mask = packet_in_mask
        self.port_status_mask = port_status_mask
        self.flow_removed_mask = flow_removed_mask

    @classmethod
    def parser(cls, datapath, version, msg_type, msg_len, xid, buf):
        msg = super(OFPGetAsyncReply, cls).parser(datapath, version,
                                                  msg_type, msg_len,
                                                  xid, buf)
        (packet_in_mask_m, packet_in_mask_s,
         port_status_mask_m, port_status_mask_s,
         flow_removed_mask_m, flow_removed_mask_s) = struct.unpack_from(
            ofproto.OFP_ASYNC_CONFIG_PACK_STR, msg.buf,
            ofproto.OFP_HEADER_SIZE)
        msg.packet_in_mask = [packet_in_mask_m, packet_in_mask_s]
        msg.port_status_mask = [port_status_mask_m, port_status_mask_s]
        msg.flow_removed_mask = [flow_removed_mask_m, flow_removed_mask_s]
        return msg


@_set_msg_type(ofproto.OFPT_SET_ASYNC)
class OFPSetAsync(MsgBase):
    """
    Set asynchronous configuration message

    The controller sends this message to set the asynchronous messages that
    it wants to receive on a given OpneFlow channel.

    ================== ====================================================
    Attribute          Description
    ================== ====================================================
    packet_in_mask     2-element array: element 0, when the controller has a
                       OFPCR_ROLE_EQUAL or OFPCR_ROLE_MASTER role. element 1,
                       OFPCR_ROLE_SLAVE role controller.
                       Bitmasks of following values.

                       | OFPR_NO_MATCH
                       | OFPR_ACTION
                       | OFPR_INVALID_TTL
    port_status_mask   2-element array.
                       Bitmasks of following values.

                       | OFPPR_ADD
                       | OFPPR_DELETE
                       | OFPPR_MODIFY
    flow_removed_mask  2-element array.
                       Bitmasks of following values.

                       | OFPRR_IDLE_TIMEOUT
                       | OFPRR_HARD_TIMEOUT
                       | OFPRR_DELETE
                       | OFPRR_GROUP_DELETE
    ================== ====================================================

    Example::

        def send_set_async(self, datapath):
            ofp = datapath.ofproto
            ofp_parser = datapath.ofproto_parser

            packet_in_mask = ofp.OFPR_ACTION | ofp.OFPR_INVALID_TTL
            port_status_mask = (ofp.OFPPR_ADD | ofp.OFPPR_DELETE |
                                ofp.OFPPR_MODIFY)
            flow_removed_mask = (ofp.OFPRR_IDLE_TIMEOUT |
                                 ofp.OFPRR_HARD_TIMEOUT |
                                 ofp.OFPRR_DELETE)
            req = ofp_parser.OFPSetAsync(datapath,
                                         [packet_in_mask, 0],
                                         [port_status_mask, 0],
                                         [flow_removed_mask, 0])
            datapath.send_msg(req)
    """
    def __init__(self, datapath,
                 packet_in_mask, port_status_mask, flow_removed_mask):
        super(OFPSetAsync, self).__init__(datapath)
        self.packet_in_mask = packet_in_mask
        self.port_status_mask = port_status_mask
        self.flow_removed_mask = flow_removed_mask

    def _serialize_body(self):
        msg_pack_into(ofproto.OFP_ASYNC_CONFIG_PACK_STR, self.buf,
                      ofproto.OFP_HEADER_SIZE,
                      self.packet_in_mask[0], self.packet_in_mask[1],
                      self.port_status_mask[0], self.port_status_mask[1],
                      self.flow_removed_mask[0], self.flow_removed_mask[1])