os-ken/os_ken/ofproto/ofproto_v1_0_parser.py

# Copyright (C) 2011, 2012 Nippon Telegraph and Telephone Corporation.
# Copyright (C) 2011, 2012 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.

"""
Decoder/Encoder implementations of OpenFlow 1.0.
"""

import struct
import base64

import six
import netaddr

from os_ken.ofproto.ofproto_parser import StringifyMixin, MsgBase
from os_ken.lib import addrconv
from os_ken.lib import ip
from os_ken.lib import mac
from os_ken.lib.packet import packet
from os_ken.lib.pack_utils import msg_pack_into
from os_ken.ofproto import nx_match
from os_ken.ofproto import ofproto_common
from os_ken.ofproto import ofproto_parser
from os_ken.ofproto import ofproto_v1_0 as ofproto
from os_ken.ofproto import nx_actions
from os_ken import utils

import logging
LOG = logging.getLogger('os_ken.ofproto.ofproto_v1_0_parser')

_MSG_PARSERS = {}


def _set_msg_type(msg_type):
    '''Annotate corresponding OFP message 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)


# OFP_MSG_REPLY = {
#     OFPFeaturesRequest: OFPSwitchFeatures,
#     OFPBarrierRequest: OFPBarrierReply,
#     OFPQueueGetConfigRequest: OFPQueueGetConfigReply,
#
#     # ofp_stats_request -> ofp_stats_reply
#     OFPDescStatsRequest: OFPDescStatsReply,
#     OFPFlowStatsRequest: OFPFlowStatsReply,
#     OFPAggregateStatsRequest: OFPAggregateStatsReply,
#     OFPTableStatsRequest: OFPTableStatsReply,
#     OFPPortStatsRequest: OFPPortStatsReply,
#     OFPQueueStatsRequest: OFPQueueStatsReply,
#     OFPVendorStatsRequest: OFPVendorStatsReply,
#     }
def _set_msg_reply(msg_reply):
    '''Annotate OFP reply message class'''
    def _set_cls_msg_reply(cls):
        cls.cls_msg_reply = msg_reply
        return cls
    return _set_cls_msg_reply


#
# common structures
#

class OFPPhyPort(ofproto_parser.namedtuple('OFPPhyPort', (
        'port_no', 'hw_addr', 'name', 'config', 'state', 'curr', 'advertised',
        'supported', 'peer'))):
    """
    Description of a port

    ========== =========================================================
    Attribute  Description
    ========== =========================================================
    port_no    Port number and it uniquely identifies a port within
               a switch.
    hw_addr    MAC address for the port.
    name       Null-terminated string containing a human-readable name
               for the interface.
    config     Bitmap of port configration flags.

               | OFPPC_PORT_DOWN
               | OFPPC_NO_STP
               | OFPPC_NO_RECV
               | OFPPC_NO_RECV_STP
               | OFPPC_NO_FLOOD
               | OFPPC_NO_FWD
               | OFPPC_NO_PACKET_IN
    state      Bitmap of port state flags.

               | OFPPS_LINK_DOWN
               | OFPPS_STP_LISTEN
               | OFPPS_STP_LEARN
               | OFPPS_STP_FORWARD
               | OFPPS_STP_BLOCK
               | OFPPS_STP_MASK
    curr       Current features.
    advertised Features being advertised by the port.
    supported  Features supported by the port.
    peer       Features advertised by peer.
    ========== =========================================================
    """
    _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_PHY_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(b'\0')
        return cls(*port)


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

    This class is implementation of the flow match structure having
    compose/query API.

    ================ ==================================================
    Attribute        Description
    ================ ==================================================
    wildcards        Wildcard fields.
    (match fields)   For the available match fields,
                     please refer to the following.
    ================ ==================================================

    ================ =============== ==================================
    Argument         Value           Description
    ================ =============== ==================================
    in_port          Integer 16bit   Switch input port.
    dl_src           MAC address     Ethernet source address.
    dl_dst           MAC address     Ethernet destination address.
    dl_vlan          Integer 16bit   Input VLAN id.
    dl_vlan_pcp      Integer 8bit    Input VLAN priority.
    dl_type          Integer 16bit   Ethernet frame type.
    nw_tos           Integer 8bit    IP ToS (actually DSCP field, 6 bits).
    nw_proto         Integer 8bit    IP protocol or lower 8 bits of
                                     ARP opcode.
    nw_src           IPv4 address    IP source address.
    nw_dst           IPv4 address    IP destination address.
    tp_src           Integer 16bit   TCP/UDP source port.
    tp_dst           Integer 16bit   TCP/UDP destination port.
    nw_src_mask      Integer 8bit    IP source address mask
                                     specified as IPv4 address prefix.
    nw_dst_mask      Integer 8bit    IP destination address mask
                                     specified as IPv4 address prefix.
    ================ =============== ==================================

    Example::

        >>> # compose
        >>> match = parser.OFPMatch(
        ...     in_port=1,
        ...     dl_type=0x0800,
        ...     dl_src='aa:bb:cc:dd:ee:ff',
        ...     nw_src='192.168.0.1')
        >>> # query
        >>> if 'nw_src' in match:
        ...     print match['nw_src']
        ...
        '192.168.0.1'
    """

    def __init__(self, wildcards=None, in_port=None, dl_src=None, dl_dst=None,
                 dl_vlan=None, dl_vlan_pcp=None, dl_type=None, nw_tos=None,
                 nw_proto=None, nw_src=None, nw_dst=None,
                 tp_src=None, tp_dst=None, nw_src_mask=32, nw_dst_mask=32):
        super(OFPMatch, self).__init__()
        wc = ofproto.OFPFW_ALL
        if in_port is None:
            self.in_port = 0
        else:
            wc &= ~ofproto.OFPFW_IN_PORT
            self.in_port = in_port

        if dl_src is None:
            self.dl_src = mac.DONTCARE
        else:
            wc &= ~ofproto.OFPFW_DL_SRC
            if (isinstance(dl_src, (six.text_type, str)) and
                    netaddr.valid_mac(dl_src)):
                dl_src = addrconv.mac.text_to_bin(dl_src)
            if dl_src == 0:
                self.dl_src = mac.DONTCARE
            else:
                self.dl_src = dl_src

        if dl_dst is None:
            self.dl_dst = mac.DONTCARE
        else:
            wc &= ~ofproto.OFPFW_DL_DST
            if (isinstance(dl_dst, (six.text_type, str)) and
                    netaddr.valid_mac(dl_dst)):
                dl_dst = addrconv.mac.text_to_bin(dl_dst)
            if dl_dst == 0:
                self.dl_dst = mac.DONTCARE
            else:
                self.dl_dst = dl_dst

        if dl_vlan is None:
            self.dl_vlan = 0
        else:
            wc &= ~ofproto.OFPFW_DL_VLAN
            self.dl_vlan = dl_vlan

        if dl_vlan_pcp is None:
            self.dl_vlan_pcp = 0
        else:
            wc &= ~ofproto.OFPFW_DL_VLAN_PCP
            self.dl_vlan_pcp = dl_vlan_pcp

        if dl_type is None:
            self.dl_type = 0
        else:
            wc &= ~ofproto.OFPFW_DL_TYPE
            self.dl_type = dl_type

        if nw_tos is None:
            self.nw_tos = 0
        else:
            wc &= ~ofproto.OFPFW_NW_TOS
            self.nw_tos = nw_tos

        if nw_proto is None:
            self.nw_proto = 0
        else:
            wc &= ~ofproto.OFPFW_NW_PROTO
            self.nw_proto = nw_proto

        if nw_src is None:
            self.nw_src = 0
        else:
            wc &= (32 - nw_src_mask) << ofproto.OFPFW_NW_SRC_SHIFT \
                | ~ofproto.OFPFW_NW_SRC_MASK
            if not isinstance(nw_src, int):
                nw_src = ip.ipv4_to_int(nw_src)
            self.nw_src = nw_src

        if nw_dst is None:
            self.nw_dst = 0
        else:
            wc &= (32 - nw_dst_mask) << ofproto.OFPFW_NW_DST_SHIFT \
                | ~ofproto.OFPFW_NW_DST_MASK
            if not isinstance(nw_dst, int):
                nw_dst = ip.ipv4_to_int(nw_dst)
            self.nw_dst = nw_dst

        if tp_src is None:
            self.tp_src = 0
        else:
            wc &= ~ofproto.OFPFW_TP_SRC
            self.tp_src = tp_src

        if tp_dst is None:
            self.tp_dst = 0
        else:
            wc &= ~ofproto.OFPFW_TP_DST
            self.tp_dst = tp_dst

        if wildcards is None:
            self.wildcards = wc
        else:
            self.wildcards = wildcards

    def __getitem__(self, name):
        if not isinstance(name, str):
            raise KeyError(name)
        elif name == 'nw_src_mask':
            _m = 32 - ((self.wildcards & ofproto.OFPFW_NW_SRC_MASK) >>
                       ofproto.OFPFW_NW_SRC_SHIFT)
            return 0 if _m < 0 else _m
        elif name == 'nw_dst_mask':
            _m = 32 - ((self.wildcards & ofproto.OFPFW_NW_DST_MASK) >>
                       ofproto.OFPFW_NW_DST_SHIFT)
            return 0 if _m < 0 else _m
        elif name == 'wildcards':
            return self.wildcards

        wc = getattr(ofproto, 'OFPFW_' + name.upper(), 0)
        if ~self.wildcards & wc:
            value = getattr(self, name)
            if name in ['dl_src', 'dl_dst']:
                value = addrconv.mac.bin_to_text(value)
            elif name in ['nw_src', 'nw_dst']:
                value = ip.ipv4_to_str(value)
            return value
        else:
            raise KeyError(name)

    def __contains__(self, name):
        wc = getattr(ofproto, 'OFPFW_' + name.upper(), 0)
        return ~self.wildcards & wc

    def serialize(self, buf, offset):
        msg_pack_into(ofproto.OFP_MATCH_PACK_STR, buf, offset,
                      self.wildcards, self.in_port, self.dl_src,
                      self.dl_dst, self.dl_vlan, self.dl_vlan_pcp,
                      self.dl_type, self.nw_tos, self.nw_proto,
                      self.nw_src, self.nw_dst, self.tp_src, self.tp_dst)

    @classmethod
    def parse(cls, buf, offset):
        match = struct.unpack_from(ofproto.OFP_MATCH_PACK_STR,
                                   buf, offset)
        return cls(*match)

    def to_jsondict(self):
        fields = {}
        # copy values to avoid original values conversion
        for k, v in self.__dict__.items():
            if k in ['dl_src', 'dl_dst']:
                fields[k] = addrconv.mac.bin_to_text(v)
            elif k in ['nw_src', 'nw_dst']:
                fields[k] = ip.ipv4_to_str(v)
            else:
                fields[k] = v
        return {self.__class__.__name__: fields}

    @classmethod
    def from_jsondict(cls, dict_):
        return cls(**dict_)


class OFPActionHeader(StringifyMixin):
    _base_attributes = ['type', 'len']

    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.
    ================ ======================================================

    Note::
        The reason of this magic number (0xffe5)
        is because there is no good constant in of1.0.
        The same value as OFPCML_MAX of of1.2 and of1.3 is used.
    """

    def __init__(self, port, max_len=0xffe5):
        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)
        assert type_ == ofproto.OFPAT_OUTPUT
        assert len_ == ofproto.OFP_ACTION_OUTPUT_SIZE
        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_SET_VLAN_VID,
                                ofproto.OFP_ACTION_VLAN_VID_SIZE)
class OFPActionVlanVid(OFPAction):
    """
    Set the 802.1q VLAN id action

    This action indicates the 802.1q VLAN id to be set.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    vlan_vid         VLAN id.
    ================ ======================================================
    """

    def __init__(self, vlan_vid):
        super(OFPActionVlanVid, self).__init__()
        self.vlan_vid = vlan_vid

    @classmethod
    def parser(cls, buf, offset):
        type_, len_, vlan_vid = struct.unpack_from(
            ofproto.OFP_ACTION_VLAN_VID_PACK_STR, buf, offset)
        assert type_ == ofproto.OFPAT_SET_VLAN_VID
        assert len_ == ofproto.OFP_ACTION_VLAN_VID_SIZE
        return cls(vlan_vid)

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


@OFPAction.register_action_type(ofproto.OFPAT_SET_VLAN_PCP,
                                ofproto.OFP_ACTION_VLAN_PCP_SIZE)
class OFPActionVlanPcp(OFPAction):
    """
    Set the 802.1q priority action

    This action indicates the 802.1q priority to be set.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    vlan_pcp         VLAN priority.
    ================ ======================================================
    """

    def __init__(self, vlan_pcp):
        super(OFPActionVlanPcp, self).__init__()
        self.vlan_pcp = vlan_pcp

    @classmethod
    def parser(cls, buf, offset):
        type_, len_, vlan_pcp = struct.unpack_from(
            ofproto.OFP_ACTION_VLAN_PCP_PACK_STR, buf, offset)
        assert type_ == ofproto.OFPAT_SET_VLAN_PCP
        assert len_ == ofproto.OFP_ACTION_VLAN_PCP_SIZE
        return cls(vlan_pcp)

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


@OFPAction.register_action_type(ofproto.OFPAT_STRIP_VLAN,
                                ofproto.OFP_ACTION_HEADER_SIZE)
class OFPActionStripVlan(OFPAction):
    """
    Strip the 802.1q header action

    This action indicates the 802.1q priority to be striped.
    """

    def __init__(self):
        super(OFPActionStripVlan, self).__init__()

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


class OFPActionDlAddr(OFPAction):
    def __init__(self, dl_addr):
        super(OFPActionDlAddr, self).__init__()
        if (isinstance(dl_addr, (six.text_type, str)) and
                netaddr.valid_mac(dl_addr)):
            dl_addr = addrconv.mac.text_to_bin(dl_addr)
        self.dl_addr = dl_addr

    @classmethod
    def parser(cls, buf, offset):
        type_, len_, dl_addr = struct.unpack_from(
            ofproto.OFP_ACTION_DL_ADDR_PACK_STR, buf, offset)
        assert type_ in (ofproto.OFPAT_SET_DL_SRC,
                         ofproto.OFPAT_SET_DL_DST)
        assert len_ == ofproto.OFP_ACTION_DL_ADDR_SIZE
        return cls(dl_addr)

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

    def to_jsondict(self):
        body = {"dl_addr": addrconv.mac.bin_to_text(self.dl_addr)}
        return {self.__class__.__name__: body}

    @classmethod
    def from_jsondict(cls, dict_):
        return cls(**dict_)


@OFPAction.register_action_type(ofproto.OFPAT_SET_DL_SRC,
                                ofproto.OFP_ACTION_DL_ADDR_SIZE)
class OFPActionSetDlSrc(OFPActionDlAddr):
    """
    Set the ethernet source address action

    This action indicates the ethernet source address to be set.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    dl_addr          Ethernet address.
    ================ ======================================================
    """

    def __init__(self, dl_addr):
        super(OFPActionSetDlSrc, self).__init__(dl_addr)


@OFPAction.register_action_type(ofproto.OFPAT_SET_DL_DST,
                                ofproto.OFP_ACTION_DL_ADDR_SIZE)
class OFPActionSetDlDst(OFPActionDlAddr):
    """
    Set the ethernet destination address action

    This action indicates the ethernet destination address to be set.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    dl_addr          Ethernet address.
    ================ ======================================================
    """

    def __init__(self, dl_addr):
        super(OFPActionSetDlDst, self).__init__(dl_addr)


class OFPActionNwAddr(OFPAction):
    def __init__(self, nw_addr):
        super(OFPActionNwAddr, self).__init__()
        if not isinstance(nw_addr, int):
            nw_addr = ip.ipv4_to_int(nw_addr)
        self.nw_addr = nw_addr

    @classmethod
    def parser(cls, buf, offset):
        type_, len_, nw_addr = struct.unpack_from(
            ofproto.OFP_ACTION_NW_ADDR_PACK_STR, buf, offset)
        assert type_ in (ofproto.OFPAT_SET_NW_SRC,
                         ofproto.OFPAT_SET_NW_DST)
        assert len_ == ofproto.OFP_ACTION_NW_ADDR_SIZE
        return cls(nw_addr)

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

    def to_jsondict(self):
        body = {"nw_addr": ip.ipv4_to_str(self.nw_addr)}
        return {self.__class__.__name__: body}

    @classmethod
    def from_jsondict(cls, dict_):
        return cls(**dict_)


@OFPAction.register_action_type(ofproto.OFPAT_SET_NW_SRC,
                                ofproto.OFP_ACTION_NW_ADDR_SIZE)
class OFPActionSetNwSrc(OFPActionNwAddr):
    """
    Set the IP source address action

    This action indicates the IP source address to be set.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    nw_addr          IP address.
    ================ ======================================================
    """

    def __init__(self, nw_addr):
        super(OFPActionSetNwSrc, self).__init__(nw_addr)


@OFPAction.register_action_type(ofproto.OFPAT_SET_NW_DST,
                                ofproto.OFP_ACTION_NW_ADDR_SIZE)
class OFPActionSetNwDst(OFPActionNwAddr):
    """
    Set the IP destination address action

    This action indicates the IP destination address to be set.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    nw_addr          IP address.
    ================ ======================================================
    """

    def __init__(self, nw_addr):
        super(OFPActionSetNwDst, self).__init__(nw_addr)


@OFPAction.register_action_type(ofproto.OFPAT_SET_NW_TOS,
                                ofproto.OFP_ACTION_NW_TOS_SIZE)
class OFPActionSetNwTos(OFPAction):
    """
    Set the IP ToS action

    This action indicates the IP ToS (DSCP field, 6 bits) to be set.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    tos              IP ToS (DSCP field, 6 bits).
    ================ ======================================================
    """

    def __init__(self, tos):
        super(OFPActionSetNwTos, self).__init__()
        self.tos = tos

    @classmethod
    def parser(cls, buf, offset):
        type_, len_, tos = struct.unpack_from(
            ofproto.OFP_ACTION_NW_TOS_PACK_STR, buf, offset)
        assert type_ == ofproto.OFPAT_SET_NW_TOS
        assert len_ == ofproto.OFP_ACTION_NW_TOS_SIZE
        return cls(tos)

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


class OFPActionTpPort(OFPAction):
    def __init__(self, tp):
        super(OFPActionTpPort, self).__init__()
        self.tp = tp

    @classmethod
    def parser(cls, buf, offset):
        type_, len_, tp = struct.unpack_from(
            ofproto.OFP_ACTION_TP_PORT_PACK_STR, buf, offset)
        assert type_ in (ofproto.OFPAT_SET_TP_SRC,
                         ofproto.OFPAT_SET_TP_DST)
        assert len_ == ofproto.OFP_ACTION_TP_PORT_SIZE
        return cls(tp)

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


@OFPAction.register_action_type(ofproto.OFPAT_SET_TP_SRC,
                                ofproto.OFP_ACTION_TP_PORT_SIZE)
class OFPActionSetTpSrc(OFPActionTpPort):
    """
    Set the TCP/UDP source port action

    This action indicates the TCP/UDP source port to be set.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    tp               TCP/UDP port.
    ================ ======================================================
    """

    def __init__(self, tp):
        super(OFPActionSetTpSrc, self).__init__(tp)


@OFPAction.register_action_type(ofproto.OFPAT_SET_TP_DST,
                                ofproto.OFP_ACTION_TP_PORT_SIZE)
class OFPActionSetTpDst(OFPActionTpPort):
    """
    Set the TCP/UDP destination port action

    This action indicates the TCP/UDP destination port to be set.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    tp               TCP/UDP port.
    ================ ======================================================
    """

    def __init__(self, tp):
        super(OFPActionSetTpDst, self).__init__(tp)


@OFPAction.register_action_type(ofproto.OFPAT_ENQUEUE,
                                ofproto.OFP_ACTION_ENQUEUE_SIZE)
class OFPActionEnqueue(OFPAction):
    """
    Output to queue action

    This action indicates send packets to given queue on port.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    port             Port that queue belongs.
    queue_id         Where to enqueue the packets.
    ================ ======================================================
    """

    def __init__(self, port, queue_id):
        super(OFPActionEnqueue, self).__init__()
        self.port = port
        self.queue_id = queue_id

    @classmethod
    def parser(cls, buf, offset):
        type_, len_, port, queue_id = struct.unpack_from(
            ofproto.OFP_ACTION_ENQUEUE_PACK_STR, buf, offset)
        assert type_ == ofproto.OFPAT_ENQUEUE
        assert len_ == ofproto.OFP_ACTION_ENQUEUE_SIZE
        return cls(port, queue_id)

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


@OFPAction.register_action_type(ofproto.OFPAT_VENDOR, 0)
class OFPActionVendor(OFPAction):
    """
    Vendor action

    This action is an extensible action for the vendor.
    """
    _ACTION_VENDORS = {}

    @staticmethod
    def register_action_vendor(vendor):
        def _register_action_vendor(cls):
            cls.cls_vendor = vendor
            OFPActionVendor._ACTION_VENDORS[cls.cls_vendor] = cls
            return cls
        return _register_action_vendor

    def __init__(self, vendor=None):
        super(OFPActionVendor, self).__init__()
        self.type = ofproto.OFPAT_VENDOR
        self.len = None

        if vendor is None:
            self.vendor = self.cls_vendor
        else:
            self.vendor = vendor

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

        data = buf[(offset + ofproto.OFP_ACTION_VENDOR_HEADER_SIZE
                    ): offset + len_]

        if vendor == ofproto_common.NX_EXPERIMENTER_ID:
            obj = NXAction.parse(data)  # noqa
        else:
            cls_ = cls._ACTION_VENDORS.get(vendor, None)

            if cls_ is None:
                obj = OFPActionVendorUnknown(vendor, data)
            else:
                obj = cls_.parser(buf, offset)

        obj.len = len_
        return obj

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


# OpenFlow1.2 or later compatible
OFPActionExperimenter = OFPActionVendor


class OFPActionVendorUnknown(OFPActionVendor):
    def __init__(self, vendor, data=None, type_=None, len_=None):
        super(OFPActionVendorUnknown,
              self).__init__(vendor=vendor)
        self.data = data

    def serialize(self, buf, offset):
        # fixup
        data = self.data
        if data is None:
            data = bytearray()
        self.len = (utils.round_up(len(data), 8) +
                    ofproto.OFP_ACTION_VENDOR_HEADER_SIZE)
        super(OFPActionVendorUnknown, self).serialize(buf, offset)
        msg_pack_into('!%ds' % len(self.data),
                      buf,
                      offset + ofproto.OFP_ACTION_VENDOR_HEADER_SIZE,
                      self.data)


@OFPActionVendor.register_action_vendor(ofproto_common.NX_EXPERIMENTER_ID)
class NXActionHeader(OFPActionVendor):
    _NX_ACTION_SUBTYPES = {}

    @staticmethod
    def register_nx_action_subtype(subtype, len_):
        def _register_nx_action_subtype(cls):
            cls.cls_action_len = len_
            cls.cls_subtype = subtype
            NXActionHeader._NX_ACTION_SUBTYPES[cls.cls_subtype] = cls
            return cls
        return _register_nx_action_subtype

    def __init__(self):
        super(NXActionHeader, self).__init__()
        self.subtype = self.cls_subtype

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

    @classmethod
    def parser(cls, buf, offset):
        type_, len_, vendor, subtype = struct.unpack_from(
            ofproto.NX_ACTION_HEADER_PACK_STR, buf, offset)
        cls_ = cls._NX_ACTION_SUBTYPES.get(subtype)
        return cls_.parser(buf, offset)


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_STATS_PACK_STR,
                                  buf, offset)
        desc = list(desc)
        desc = [x.rstrip(b'\0') for x in desc]
        stats = cls(*desc)
        stats.length = ofproto.OFP_DESC_STATS_SIZE
        return stats


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

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

        flow_stats.length, flow_stats.table_id = struct.unpack_from(
            ofproto.OFP_FLOW_STATS_0_PACK_STR, buf, offset)
        offset += ofproto.OFP_FLOW_STATS_0_SIZE

        flow_stats.match = OFPMatch.parse(buf, offset)
        offset += ofproto.OFP_MATCH_SIZE

        (flow_stats.duration_sec,
         flow_stats.duration_nsec,
         flow_stats.priority,
         flow_stats.idle_timeout,
         flow_stats.hard_timeout,
         flow_stats.cookie,
         flow_stats.packet_count,
         flow_stats.byte_count) = struct.unpack_from(
            ofproto.OFP_FLOW_STATS_1_PACK_STR, buf, offset)
        offset += ofproto.OFP_FLOW_STATS_1_SIZE

        flow_stats.actions = []
        length = ofproto.OFP_FLOW_STATS_SIZE
        while length < flow_stats.length:
            action = OFPAction.parser(buf, offset)
            flow_stats.actions.append(action)

            offset += action.len
            length += action.len

        return flow_stats


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


class OFPTableStats(ofproto_parser.namedtuple('OFPTableStats', (
        'table_id', 'name', 'wildcards', 'max_entries', 'active_count',
        'lookup_count', 'matched_count'))):

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

    @classmethod
    def parser(cls, buf, offset):
        tbl = struct.unpack_from(ofproto.OFP_TABLE_STATS_PACK_STR,
                                 buf, offset)
        tbl = list(tbl)
        i = cls._fields.index('name')
        tbl[i] = tbl[i].rstrip(b'\0')
        stats = cls(*tbl)
        stats.length = ofproto.OFP_TABLE_STATS_SIZE
        return stats


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'))):
    @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


class OFPQueueStats(ofproto_parser.namedtuple('OFPQueueStats', (
        'port_no', 'queue_id', 'tx_bytes', 'tx_packets', 'tx_errors'))):
    @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


class OFPVendorStats(ofproto_parser.namedtuple('OFPVendorStats',
                                               ('specific_data'))):
    @classmethod
    def parser(cls, buf, offset):
        stats = cls(buf[offset:])
        stats.length = len(stats.specific_data)
        return stats


class NXFlowStats(StringifyMixin):
    def __init__(self):
        super(NXFlowStats, self).__init__()
        self.length = None
        self.table_id = None
        self.duration_sec = None
        self.duration_nsec = None
        self.priority = None
        self.idle_timeout = None
        self.hard_timeout = None
        self.match_len = None
        self.idle_age = None
        self.hard_age = None
        self.cookie = None
        self.packet_count = None
        self.byte_count = None

    @classmethod
    def parser(cls, buf, offset):
        original_offset = offset
        nxflow_stats = cls()
        (nxflow_stats.length, nxflow_stats.table_id,
         nxflow_stats.duration_sec, nxflow_stats.duration_nsec,
         nxflow_stats.priority, nxflow_stats.idle_timeout,
         nxflow_stats.hard_timeout, nxflow_stats.match_len,
         nxflow_stats.idle_age, nxflow_stats.hard_age,
         nxflow_stats.cookie, nxflow_stats.packet_count,
         nxflow_stats.byte_count) = struct.unpack_from(
            ofproto.NX_FLOW_STATS_PACK_STR, buf, offset)
        offset += ofproto.NX_FLOW_STATS_SIZE

        fields = []
        match_len = nxflow_stats.match_len
        match_len -= 4
        while match_len > 0:
            field = nx_match.MFField.parser(buf, offset)
            offset += field.length
            match_len -= field.length
            fields.append(field)
        nxflow_stats.fields = fields

        actions = []
        total_len = original_offset + nxflow_stats.length
        match_len = nxflow_stats.match_len
        offset += utils.round_up(match_len, 8) - match_len
        while offset < total_len:
            action = OFPAction.parser(buf, offset)
            actions.append(action)
            offset += action.len
        nxflow_stats.actions = actions

        return nxflow_stats


class NXAggregateStats(ofproto_parser.namedtuple('NXAggregateStats', (
        'packet_count', 'byte_count', 'flow_count'))):
    @classmethod
    def parser(cls, buf, offset):
        agg = struct.unpack_from(
            ofproto.NX_AGGREGATE_STATS_REPLY_PACK_STR, buf, offset)
        stats = cls(*agg)
        stats.length = ofproto.NX_AGGREGATE_STATS_REPLY_SIZE

        return stats


class OFPQueuePropHeader(StringifyMixin):
    _QUEUE_PROPERTIES = {}

    @staticmethod
    def register_queue_property(prop_type, prop_len):
        def _register_queue_propery(cls):
            cls.cls_prop_type = prop_type
            cls.cls_prop_len = prop_len
            OFPQueuePropHeader._QUEUE_PROPERTIES[prop_type] = cls
            return cls
        return _register_queue_propery

    def __init__(self):
        self.property = self.cls_prop_type
        self.len = self.cls_prop_len

    @classmethod
    def parser(cls, buf, offset):
        property_, len_ = struct.unpack_from(
            ofproto.OFP_QUEUE_PROP_HEADER_PACK_STR, buf, offset)
        prop_cls = cls._QUEUE_PROPERTIES[property_]
        assert property_ == prop_cls.cls_prop_type
        assert len_ == prop_cls.cls_prop_len

        offset += ofproto.OFP_QUEUE_PROP_HEADER_SIZE
        return prop_cls.parser(buf, offset)


@OFPQueuePropHeader.register_queue_property(
    ofproto.OFPQT_NONE, ofproto.OFP_QUEUE_PROP_HEADER_SIZE)
class OFPQueuePropNone(OFPQueuePropHeader):
    def __init__(self):
        super(OFPQueuePropNone, self).__init__()

    @classmethod
    def parser(cls, buf, offset):
        return cls()


@OFPQueuePropHeader.register_queue_property(
    ofproto.OFPQT_MIN_RATE, ofproto.OFP_QUEUE_PROP_MIN_RATE_SIZE)
class OFPQueuePropMinRate(OFPQueuePropHeader):
    def __init__(self, rate):
        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)


class OFPPacketQueue(StringifyMixin):
    """
    Description of a queue

    ========== =========================================================
    Attribute  Description
    ========== =========================================================
    queue_id   ID for the specific queue.
    len        Length in bytes of this queue desc.
    properties List of ``OFPQueueProp*`` instance.
    ========== =========================================================
    """

    def __init__(self, queue_id, len_):
        self.queue_id = queue_id
        self.len = len_
        self.properties = None

    @classmethod
    def parser(cls, buf, offset):
        queue_id, len_ = struct.unpack_from(
            ofproto.OFP_PACKET_QUEUE_PQCK_STR, buf, offset)
        packet_queue = cls(queue_id, len_)

        packet_queue.properties = []
        cur_len = ofproto.OFP_PACKET_QUEUE_SIZE
        offset += ofproto.OFP_PACKET_QUEUE_SIZE
        while (cur_len + ofproto.OFP_QUEUE_PROP_HEADER_SIZE <=
               packet_queue.len):
            prop = OFPQueuePropHeader.parser(buf, offset)
            packet_queue.properties.append(prop)

            cur_len += prop.len
            offset += prop.len

        return packet_queue

#
# Symmetric messages
# parser + serializer
#


@_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 OSKen framework, so the OSKen application
    do not need to process this typically.
    """

    def __init__(self, datapath):
        super(OFPHello, self).__init__(datapath)


@_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 ``os_ken.ofproto.ofproto``.

    =========================== ===========
    Type                        Code
    =========================== ===========
    OFPET_HELLO_FAILED          OFPHFC_*
    OFPET_BAD_REQUEST           OFPBRC_*
    OFPET_BAD_ACTION            OFPBAC_*
    OFPET_FLOW_MOD_FAILED       OFPFMFC_*
    OFPET_PORT_MOD_FAILED       OFPPMFC_*
    OFPET_QUEUE_OP_FAILED       OFPQOFC_*
    =========================== ===========

    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
        if isinstance(data, six.string_types):
            data = data.encode('ascii')
        self.data = data

    @classmethod
    def parser(cls, 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


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

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

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

    Example::

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

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

    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 OSKen framework, so the OSKen application
    do not need to process this typically.

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

    Example::

        @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_VENDOR)
class OFPVendor(MsgBase):
    """
    Vendor message

    The controller send this message to send the vendor-specific
    information to a switch.
    """
    _VENDORS = {}

    @staticmethod
    def register_vendor(id_):
        def _register_vendor(cls):
            OFPVendor._VENDORS[id_] = cls
            return cls
        return _register_vendor

    def __init__(self, datapath):
        super(OFPVendor, self).__init__(datapath)
        self.data = None
        self.vendor = None

    @classmethod
    def parser(cls, datapath, version, msg_type, msg_len, xid, buf):
        msg = super(OFPVendor, cls).parser(datapath, version, msg_type,
                                           msg_len, xid, buf)
        (msg.vendor,) = struct.unpack_from(
            ofproto.OFP_VENDOR_HEADER_PACK_STR, msg.buf,
            ofproto.OFP_HEADER_SIZE)

        cls_ = cls._VENDORS.get(msg.vendor)
        if cls_:
            msg.data = cls_.parser(datapath, msg.buf, 0)
        else:
            msg.data = msg.buf[ofproto.OFP_VENDOR_HEADER_SIZE:]

        return msg

    def serialize_header(self):
        msg_pack_into(ofproto.OFP_VENDOR_HEADER_PACK_STR,
                      self.buf, ofproto.OFP_HEADER_SIZE, self.vendor)

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


@OFPVendor.register_vendor(ofproto_common.NX_EXPERIMENTER_ID)
class NiciraHeader(OFPVendor):
    _NX_SUBTYPES = {}

    @staticmethod
    def register_nx_subtype(subtype):
        def _register_nx_subtype(cls):
            cls.cls_subtype = subtype
            NiciraHeader._NX_SUBTYPES[cls.cls_subtype] = cls
            return cls
        return _register_nx_subtype

    def __init__(self, datapath, subtype):
        super(NiciraHeader, self).__init__(datapath)
        self.vendor = ofproto_common.NX_EXPERIMENTER_ID
        self.subtype = subtype

    def serialize_header(self):
        super(NiciraHeader, self).serialize_header()
        msg_pack_into(ofproto.NICIRA_HEADER_PACK_STR,
                      self.buf, ofproto.OFP_HEADER_SIZE,
                      self.vendor, self.subtype)

    @classmethod
    def parser(cls, datapath, buf, offset):
        vendor, subtype = struct.unpack_from(
            ofproto.NICIRA_HEADER_PACK_STR, buf,
            offset + ofproto.OFP_HEADER_SIZE)
        cls_ = cls._NX_SUBTYPES.get(subtype)
        return cls_.parser(datapath, buf,
                           offset + ofproto.NICIRA_HEADER_SIZE)


class NXTSetFlowFormat(NiciraHeader):
    def __init__(self, datapath, flow_format):
        super(NXTSetFlowFormat, self).__init__(
            datapath, ofproto.NXT_SET_FLOW_FORMAT)
        self.format = flow_format

    def _serialize_body(self):
        self.serialize_header()
        msg_pack_into(ofproto.NX_SET_FLOW_FORMAT_PACK_STR,
                      self.buf, ofproto.NICIRA_HEADER_SIZE, self.format)


class NXTFlowMod(NiciraHeader):
    def __init__(self, datapath, cookie, command,
                 idle_timeout=0, hard_timeout=0,
                 priority=ofproto.OFP_DEFAULT_PRIORITY,
                 buffer_id=0xffffffff, out_port=ofproto.OFPP_NONE,
                 flags=0, rule=None, actions=None):

        # the argument, rule, is positioned at the one before the last due
        # to the layout struct nxt_flow_mod.
        # Although rule must be given, default argument to rule, None,
        # is given to allow other default value of argument before rule.
        assert rule is not None

        if actions is None:
            actions = []
        super(NXTFlowMod, self).__init__(datapath, ofproto.NXT_FLOW_MOD)
        self.cookie = cookie
        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.flags = flags
        self.rule = rule
        self.actions = actions

    def _serialize_body(self):
        self.serialize_header()

        offset = ofproto.NX_FLOW_MOD_SIZE
        match_len = nx_match.serialize_nxm_match(self.rule, self.buf, offset)
        offset += nx_match.round_up(match_len)

        msg_pack_into(ofproto.NX_FLOW_MOD_PACK_STR,
                      self.buf, ofproto.NICIRA_HEADER_SIZE,
                      self.cookie, self.command, self.idle_timeout,
                      self.hard_timeout, self.priority, self.buffer_id,
                      self.out_port, self.flags, match_len)

        if self.actions is not None:
            for a in self.actions:
                a.serialize(self.buf, offset)
                offset += a.len


class NXTRoleRequest(NiciraHeader):
    def __init__(self, datapath, role):
        super(NXTRoleRequest, self).__init__(
            datapath, ofproto.NXT_ROLE_REQUEST)
        self.role = role

    def _serialize_body(self):
        self.serialize_header()
        msg_pack_into(ofproto.NX_ROLE_PACK_STR,
                      self.buf, ofproto.NICIRA_HEADER_SIZE, self.role)


@NiciraHeader.register_nx_subtype(ofproto.NXT_ROLE_REPLY)
class NXTRoleReply(NiciraHeader):
    def __init__(self, datapath, role):
        super(NXTRoleReply, self).__init__(
            datapath, ofproto.NXT_ROLE_REPLY)
        self.role = role

    @classmethod
    def parser(cls, datapath, buf, offset):
        (role,) = struct.unpack_from(
            ofproto.NX_ROLE_PACK_STR, buf, offset)
        return cls(datapath, role)


class NXTFlowModTableId(NiciraHeader):
    def __init__(self, datapath, set_):
        super(NXTFlowModTableId, self).__init__(
            datapath, ofproto.NXT_FLOW_MOD_TABLE_ID)
        self.set = set_

    def _serialize_body(self):
        self.serialize_header()
        msg_pack_into(ofproto.NX_FLOW_MOD_TABLE_ID_PACK_STR,
                      self.buf, ofproto.NICIRA_HEADER_SIZE,
                      self.set)


@NiciraHeader.register_nx_subtype(ofproto.NXT_FLOW_REMOVED)
class NXTFlowRemoved(NiciraHeader):
    def __init__(self, datapath, cookie, priority, reason,
                 duration_sec, duration_nsec, idle_timeout, match_len,
                 packet_count, byte_count, match):
        super(NXTFlowRemoved, self).__init__(
            datapath, ofproto.NXT_FLOW_REMOVED)
        self.cookie = cookie
        self.priority = priority
        self.reason = reason
        self.duration_sec = duration_sec
        self.duration_nsec = duration_nsec
        self.idle_timeout = idle_timeout
        self.match_len = match_len
        self.packet_count = packet_count
        self.byte_count = byte_count
        self.match = match

    @classmethod
    def parser(cls, datapath, buf, offset):
        (cookie, priority, reason, duration_sec, duration_nsec,
         idle_timeout, match_len,
         packet_count, byte_count) = struct.unpack_from(
            ofproto.NX_FLOW_REMOVED_PACK_STR, buf, offset)
        offset += (ofproto.NX_FLOW_REMOVED_SIZE -
                   ofproto.NICIRA_HEADER_SIZE)
        match = nx_match.NXMatch.parser(buf, offset, match_len)
        return cls(datapath, cookie, priority, reason, duration_sec,
                   duration_nsec, idle_timeout, match_len, packet_count,
                   byte_count, match)


class NXTSetPacketInFormat(NiciraHeader):
    def __init__(self, datapath, packet_in_format):
        super(NXTSetPacketInFormat, self).__init__(
            datapath, ofproto.NXT_SET_PACKET_IN_FORMAT)
        self.format = packet_in_format

    def _serialize_body(self):
        self.serialize_header()
        msg_pack_into(ofproto.NX_SET_PACKET_IN_FORMAT_PACK_STR,
                      self.buf, ofproto.NICIRA_HEADER_SIZE,
                      self.format)


@NiciraHeader.register_nx_subtype(ofproto.NXT_PACKET_IN)
class NXTPacketIn(NiciraHeader):
    def __init__(self, datapath, buffer_id, total_len, reason, table_id,
                 cookie, match_len, match, frame):
        super(NXTPacketIn, self).__init__(
            datapath, ofproto.NXT_PACKET_IN)
        self.buffer_id = buffer_id
        self.total_len = total_len
        self.reason = reason
        self.table_id = table_id
        self.cookie = cookie
        self.match_len = match_len
        self.match = match
        self.frame = frame

    @classmethod
    def parser(cls, datapath, buf, offset):
        (buffer_id, total_len, reason, table_id,
         cookie, match_len) = struct.unpack_from(
            ofproto.NX_PACKET_IN_PACK_STR, buf, offset)

        offset += (ofproto.NX_PACKET_IN_SIZE -
                   ofproto.NICIRA_HEADER_SIZE)

        match = nx_match.NXMatch.parser(buf, offset, match_len)
        offset += (match_len + 7) // 8 * 8
        frame = buf[offset:]
        if total_len < len(frame):
            frame = frame[:total_len]
        return cls(datapath, buffer_id, total_len, reason, table_id,
                   cookie, match_len, match, frame)


class NXTFlowAge(NiciraHeader):
    def __init__(self, datapath):
        super(NXTFlowAge, self).__init__(
            datapath, ofproto.NXT_FLOW_AGE)

    def _serialize_body(self):
        self.serialize_header()


class NXTSetAsyncConfig(NiciraHeader):
    def __init__(self, datapath, packet_in_mask, port_status_mask,
                 flow_removed_mask):
        super(NXTSetAsyncConfig, self).__init__(
            datapath, ofproto.NXT_SET_ASYNC_CONFIG)
        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):
        self.serialize_header()
        msg_pack_into(ofproto.NX_ASYNC_CONFIG_PACK_STR,
                      self.buf, ofproto.NICIRA_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])


class NXTSetControllerId(NiciraHeader):
    def __init__(self, datapath, controller_id):
        super(NXTSetControllerId, self).__init__(
            datapath, ofproto.NXT_SET_CONTROLLER_ID)
        self.controller_id = controller_id

    def _serialize_body(self):
        self.serialize_header()
        msg_pack_into(ofproto.NX_CONTROLLER_ID_PACK_STR,
                      self.buf, ofproto.NICIRA_HEADER_SIZE,
                      self.controller_id)


#
# asymmetric message (datapath -> controller)
# parser only
#


@_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 OSKen framework, so the OSKen application
    do not need to process this typically.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    datapath_id      Datapath unique ID.
    n_buffers        Max packets buffered at once.
    n_tables         Number of tables supported by datapath.
    capabilities     Bitmap of capabilities flag.

                     | OFPC_FLOW_STATS
                     | OFPC_TABLE_STATS
                     | OFPC_PORT_STATS
                     | OFPC_STP
                     | OFPC_RESERVED
                     | OFPC_IP_REASM
                     | OFPC_QUEUE_STATS
                     | OFPC_ARP_MATCH_IP
    actions          Bitmap of supported OFPAT_*.
    ports            List of ``OFPPhyPort`` instances.
    ================ ======================================================

    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 capabilities=0x%08x ports=%s',
                              msg.datapath_id, msg.n_buffers, msg.n_tables,
                              msg.capabilities, msg.ports)
    """

    def __init__(self, datapath, datapath_id=None, n_buffers=None,
                 n_tables=None, capabilities=None, actions=None, ports=None):
        super(OFPSwitchFeatures, self).__init__(datapath)
        self.datapath_id = datapath_id
        self.n_buffers = n_buffers
        self.n_tables = n_tables
        self.capabilities = capabilities
        self.actions = actions
        self.ports = ports

    @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.capabilities,
         msg.actions) = struct.unpack_from(
            ofproto.OFP_SWITCH_FEATURES_PACK_STR, msg.buf,
            ofproto.OFP_HEADER_SIZE)

        msg.ports = {}
        n_ports = ((msg_len - ofproto.OFP_SWITCH_FEATURES_SIZE) //
                   ofproto.OFP_PHY_PORT_SIZE)
        offset = ofproto.OFP_SWITCH_FEATURES_SIZE
        for _i in range(n_ports):
            port = OFPPhyPort.parser(msg.buf, offset)
            # print 'port = %s' % str(port)
            msg.ports[port.port_no] = port
            offset += ofproto.OFP_PHY_PORT_SIZE

        return msg


@_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 ``OFPPhyPort``
    ================ ======================================================

    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 = OFPPhyPort.parser(msg.buf,
                                     ofproto.OFP_PORT_STATUS_DESC_OFFSET)
        return msg


@_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.
    in_port       Port on which frame was received.
    reason        Reason packet is being sent.

                  | OFPR_NO_MATCH
                  | OFPR_ACTION
                  | OFPR_INVALID_TTL
    data          Ethernet frame.
    ============= =========================================================

    Example::

        @set_ev_cls(ofp_event.EventOFPPacketIn, MAIN_DISPATCHER)
        def packet_in_handler(self, ev):
            msg = ev.msg
            dp = msg.datapath
            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 in_port=%d, '
                              'reason=%s data=%s',
                              msg.buffer_id, msg.total_len, msg.in_port,
                              reason, utils.hex_array(msg.data))
    """

    def __init__(self, datapath, buffer_id=None, total_len=None, in_port=None,
                 reason=None, data=None):
        super(OFPPacketIn, self).__init__(datapath)
        self.buffer_id = buffer_id
        self.total_len = total_len
        self.in_port = in_port
        self.reason = reason
        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.in_port,
         msg.reason) = struct.unpack_from(
            ofproto.OFP_PACKET_IN_PACK_STR,
            msg.buf, ofproto.OFP_HEADER_SIZE)
        msg.data = msg.buf[ofproto.OFP_PACKET_IN_SIZE:]
        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_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         One of the following configuration 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

            if msg.flags == ofp.OFPC_FRAG_NORMAL:
                flags = 'NORMAL'
            elif msg.flags == ofp.OFPC_FRAG_DROP:
                flags = 'DROP'
            elif msg.flags == ofp.OFPC_FRAG_REASM:
                flags = 'REASM'
            elif msg.flags == ofp.OFPC_FRAG_MASK:
                flags = 'MASK'
            else:
                flags = 'unknown'
            self.logger.debug('OFPGetConfigReply received: '
                              'flags=%s miss_send_len=%d',
                              flags, msg.miss_send_len)
    """

    def __init__(self, datapath):
        super(OFPGetConfigReply, self).__init__(datapath)

    @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


@_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)


@_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
    ================ ======================================================
    match            Instance of ``OFPMatch``.
    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
    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.
    packet_count     Number of packets that was associated with the flow.
    byte_count       Number of bytes that was associated with the flow.
    ================ ======================================================

    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: '
                              'match=%s cookie=%d priority=%d reason=%s '
                              'duration_sec=%d duration_nsec=%d '
                              'idle_timeout=%d packet_count=%d byte_count=%d',
                              msg.match, msg.cookie, msg.priority, reason,
                              msg.duration_sec, msg.duration_nsec,
                              msg.idle_timeout, msg.packet_count,
                              msg.byte_count)
    """

    def __init__(self, datapath):
        super(OFPFlowRemoved, self).__init__(datapath)

    @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.match = OFPMatch.parse(msg.buf, ofproto.OFP_HEADER_SIZE)

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

        return msg


@_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
    ================ ======================================================
    port             Port to be queried.
    queues           List of ``OFPPacketQueue`` instance.
    ================ ======================================================

    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):
        super(OFPQueueGetConfigReply, self).__init__(datapath)

    @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)

        offset = ofproto.OFP_HEADER_SIZE
        (msg.port,) = struct.unpack_from(
            ofproto.OFP_QUEUE_GET_CONFIG_REPLY_PACK_STR, msg.buf, offset)

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

            offset += queue.len

        return msg


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


@_register_parser
@_set_msg_type(ofproto.OFPT_STATS_REPLY)
class OFPStatsReply(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 OFPStatsReply._STATS_MSG_TYPES
            assert cls.cls_stats_body_cls is not None
            cls.cls_body_single_struct = body_single_struct
            OFPStatsReply._STATS_MSG_TYPES[cls.cls_stats_type] = cls
            return cls
        return _register_stats_type

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

    @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):
        # call MsgBase::parser, not OFPStatsReply::parser
        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_STATS_MSG_SIZE)
        return msg

    @classmethod
    def parser(cls, datapath, version, msg_type, msg_len, xid, buf):
        type_, flags = struct.unpack_from(ofproto.OFP_STATS_MSG_PACK_STR,
                                          six.binary_type(buf),
                                          ofproto.OFP_HEADER_SIZE)
        stats_type_cls = cls._STATS_MSG_TYPES.get(type_)
        msg = stats_type_cls.parser_stats(
            datapath, version, msg_type, msg_len, xid, buf)
        msg.type = type_
        msg.flags = flags
        return msg


@OFPStatsReply.register_stats_type(body_single_struct=True)
@_set_stats_type(ofproto.OFPST_DESC, OFPDescStats)
@_set_msg_type(ofproto.OFPT_STATS_REPLY)
class OFPDescStatsReply(OFPStatsReply):
    """
    Description statistics reply message

    The switch responds with a stats reply that include this message to
    a description statistics request.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    mfr_desc         Manufacturer description.
    hw_desc          Hardware description.
    sw_desc          Software description.
    serial_num       Serial number.
    dp_desc          Human readable description of datapath.
    ================ ======================================================

    Example::

        @set_ev_cls(ofp_event.EventOFPDescStatsReply, MAIN_DISPATCHER)
        def desc_stats_reply_handler(self, ev):
            msg = ev.msg
            ofp = msg.datapath.ofproto
            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):
        super(OFPDescStatsReply, self).__init__(datapath)


@OFPStatsReply.register_stats_type()
@_set_stats_type(ofproto.OFPST_FLOW, OFPFlowStats)
@_set_msg_type(ofproto.OFPT_STATS_REPLY)
class OFPFlowStatsReply(OFPStatsReply):
    """
    Individual flow statistics reply message

    The switch responds with a stats reply that include this message to
    an individual flow statistics request.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    table_id         ID of table flow came from.
    match            Instance of ``OFPMatch``.
    duration_sec     Time flow has been alive in seconds.
    duration_nsec    Time flow has been alive in nanoseconds beyond
                     duration_sec.
    priority         Priority of the entry. Only meaningful
                     when this is not an exact-match entry.
    idle_timeout     Number of seconds idle before expiration.
    hard_timeout     Number of seconds before expiration.
    cookie           Opaque controller-issued identifier.
    packet_count     Number of packets in flow.
    byte_count       Number of bytes in flow.
    actions          List of ``OFPAction*`` instance
    ================ ======================================================

    Example::

        @set_ev_cls(ofp_event.EventOFPFlowStatsReply, MAIN_DISPATCHER)
        def flow_stats_reply_handler(self, ev):
            msg = ev.msg
            ofp = msg.datapath.ofproto
            body = ev.msg.body

            flows = []
            for stat in body:
                flows.append('table_id=%s match=%s '
                             'duration_sec=%d duration_nsec=%d '
                             'priority=%d '
                             'idle_timeout=%d hard_timeout=%d '
                             'cookie=%d packet_count=%d byte_count=%d '
                             'actions=%s' %
                             (stat.table_id, stat.match,
                              stat.duration_sec, stat.duration_nsec,
                              stat.priority,
                              stat.idle_timeout, stat.hard_timeout,
                              stat.cookie, stat.packet_count, stat.byte_count,
                              stat.actions))
            self.logger.debug('FlowStats: %s', flows)
    """

    def __init__(self, datapath):
        super(OFPFlowStatsReply, self).__init__(datapath)


@OFPStatsReply.register_stats_type()
@_set_stats_type(ofproto.OFPST_AGGREGATE, OFPAggregateStats)
@_set_msg_type(ofproto.OFPT_STATS_REPLY)
class OFPAggregateStatsReply(OFPStatsReply):
    """
    Aggregate flow statistics reply message

    The switch responds with a stats reply that include this message to
    an aggregate flow statistics request.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    packet_count     Number of packets in flows.
    byte_count       Number of bytes in flows.
    flow_count       Number of flows.
    ================ ======================================================

    Example::

        @set_ev_cls(ofp_event.EventOFPAggregateStatsReply, MAIN_DISPATCHER)
        def aggregate_stats_reply_handler(self, ev):
            msg = ev.msg
            ofp = msg.datapath.ofproto
            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):
        super(OFPAggregateStatsReply, self).__init__(datapath)


@OFPStatsReply.register_stats_type()
@_set_stats_type(ofproto.OFPST_TABLE, OFPTableStats)
@_set_msg_type(ofproto.OFPT_STATS_REPLY)
class OFPTableStatsReply(OFPStatsReply):
    """
    Table statistics reply message

    The switch responds with a stats reply that include this message to
    a table statistics request.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    table_id         ID of table.
    name             table name.
    wildcards        Bitmap of OFPFW_* wildcards that are
                     supported by the table.
    max_entries      Max number of entries supported
    active_count     Number of active entries
    lookup_count     Number of packets looked up in table
    matched_count    Number of packets that hit table
    ================ ======================================================

    Example::

        @set_ev_cls(ofp_event.EventOFPTableStatsReply, MAIN_DISPATCHER)
        def stats_reply_handler(self, ev):
            msg = ev.msg
            ofp = msg.datapath.ofproto
            body = ev.msg.body

            tables = []
            for stat in body:
                tables.append('table_id=%d name=%s wildcards=0x%02x '
                              'max_entries=%d active_count=%d '
                              'lookup_count=%d matched_count=%d' %
                              (stat.table_id, stat.name, stat.wildcards,
                               stat.max_entries, stat.active_count,
                               stat.lookup_count, stat.matched_count))
            self.logger.debug('TableStats: %s', tables)
    """

    def __init__(self, datapath):
        super(OFPTableStatsReply, self).__init__(datapath)


@OFPStatsReply.register_stats_type()
@_set_stats_type(ofproto.OFPST_PORT, OFPPortStats)
@_set_msg_type(ofproto.OFPT_STATS_REPLY)
class OFPPortStatsReply(OFPStatsReply):
    """
    Port statistics reply message

    The switch responds with a stats reply that include this message to
    a port statistics request.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    port_no          Port number.
    rx_packets       Number of received packets.
    tx_packets       Number of transmitted packets.
    rx_bytes         Number of received bytes.
    tx_bytes         Number of transmitted bytes.
    rx_dropped       Number of packets dropped by RX.
    tx_dropped       Number of packets dropped by TX.
    rx_errors        Number of receive errors.
    tx_errors        Number of transmit errors.
    rx_frame_err     Number of frame alignment errors.
    rx_over_err      Number of packet with RX overrun.
    rx_crc_err       Number of CRC errors.
    collisions       Number of collisions.
    ================ ======================================================

    Example::

        @set_ev_cls(ofp_event.EventOFPPortStatsReply, MAIN_DISPATCHER)
        def port_stats_reply_handler(self, ev):
            msg = ev.msg
            ofp = msg.datapath.ofproto
            body = ev.msg.body

            ports = []
            for stat in 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' %
                             (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))
            self.logger.debug('PortStats: %s', ports)
    """

    def __init__(self, datapath):
        super(OFPPortStatsReply, self).__init__(datapath)


@OFPStatsReply.register_stats_type()
@_set_stats_type(ofproto.OFPST_QUEUE, OFPQueueStats)
@_set_msg_type(ofproto.OFPT_STATS_REPLY)
class OFPQueueStatsReply(OFPStatsReply):
    """
    Queue statistics reply message

    The switch responds with a stats reply that include this message to
    an aggregate flow statistics request.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    port_no          Port number.
    queue_id         ID of queue.
    tx_bytes         Number of transmitted bytes.
    tx_packets       Number of transmitted packets.
    tx_errors        Number of packets dropped due to overrun.
    ================ ======================================================

    Example::

        @set_ev_cls(ofp_event.EventOFPQueueStatsReply, MAIN_DISPATCHER)
        def stats_reply_handler(self, ev):
            msg = ev.msg
            ofp = msg.datapath.ofproto
            body = ev.msg.body

            queues = []
            for stat in body:
                queues.append('port_no=%d queue_id=%d '
                              'tx_bytes=%d tx_packets=%d tx_errors=%d ' %
                              (stat.port_no, stat.queue_id,
                               stat.tx_bytes, stat.tx_packets, stat.tx_errors))
            self.logger.debug('QueueStats: %s', queues)
    """

    def __init__(self, datapath):
        super(OFPQueueStatsReply, self).__init__(datapath)


@OFPStatsReply.register_stats_type()
@_set_stats_type(ofproto.OFPST_VENDOR, OFPVendorStats)
@_set_msg_type(ofproto.OFPT_STATS_REPLY)
class OFPVendorStatsReply(OFPStatsReply):
    """
    Vendor statistics reply message

    The switch responds with a stats reply that include this message to
    an vendor statistics request.
    """
    _STATS_VENDORS = {}

    @staticmethod
    def register_stats_vendor(vendor):
        def _register_stats_vendor(cls):
            cls.cls_vendor = vendor
            OFPVendorStatsReply._STATS_VENDORS[cls.cls_vendor] = cls
            return cls
        return _register_stats_vendor

    def __init__(self, datapath):
        super(OFPVendorStatsReply, self).__init__(datapath)

    @classmethod
    def parser_stats(cls, datapath, version, msg_type, msg_len, xid,
                     buf):
        (type_,) = struct.unpack_from(
            ofproto.OFP_VENDOR_STATS_MSG_PACK_STR, six.binary_type(buf),
            ofproto.OFP_STATS_MSG_SIZE)

        cls_ = cls._STATS_VENDORS.get(type_)

        if cls_ is None:
            msg = MsgBase.parser.__func__(
                cls, datapath, version, msg_type, msg_len, xid, buf)
            body_cls = cls.cls_stats_body_cls
            body = body_cls.parser(buf,
                                   ofproto.OFP_STATS_MSG_SIZE)
            msg.body = body
            return msg

        return cls_.parser(
            datapath, version, msg_type, msg_len, xid, buf,
            ofproto.OFP_VENDOR_STATS_MSG_SIZE)


@OFPVendorStatsReply.register_stats_vendor(ofproto_common.NX_EXPERIMENTER_ID)
class NXStatsReply(OFPStatsReply):
    _NX_STATS_TYPES = {}

    @staticmethod
    def register_nx_stats_type(body_single_struct=False):
        def _register_nx_stats_type(cls):
            assert cls.cls_stats_type is not None
            assert cls.cls_stats_type not in \
                NXStatsReply._NX_STATS_TYPES
            assert cls.cls_stats_body_cls is not None
            cls.cls_body_single_struct = body_single_struct
            NXStatsReply._NX_STATS_TYPES[cls.cls_stats_type] = cls
            return cls
        return _register_nx_stats_type

    @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, offset):
        msg = MsgBase.parser.__func__(
            cls, datapath, version, msg_type, msg_len, xid, buf)
        msg.body = msg.parser_stats_body(msg.buf, msg.msg_len, offset)

        return msg

    @classmethod
    def parser(cls, datapath, version, msg_type, msg_len, xid, buf,
               offset):
        (type_,) = struct.unpack_from(
            ofproto.NX_STATS_MSG_PACK_STR, six.binary_type(buf), offset)
        offset += ofproto.NX_STATS_MSG0_SIZE

        cls_ = cls._NX_STATS_TYPES.get(type_)

        msg = cls_.parser_stats(
            datapath, version, msg_type, msg_len, xid, buf, offset)

        return msg


@NXStatsReply.register_nx_stats_type()
@_set_stats_type(ofproto.NXST_FLOW, NXFlowStats)
class NXFlowStatsReply(NXStatsReply):
    def __init__(self, datapath):
        super(NXFlowStatsReply, self).__init__(datapath)


@NXStatsReply.register_nx_stats_type()
@_set_stats_type(ofproto.NXST_AGGREGATE, NXAggregateStats)
class NXAggregateStatsReply(NXStatsReply):
    def __init__(self, datapath):
        super(NXAggregateStatsReply, self).__init__(datapath)


#
# controller-to-switch message
# serializer only
#


@_set_msg_reply(OFPSwitchFeatures)
@_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 OSKen framework, so the OSKen 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)


@_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)


@_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         One of the following configuration 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::

        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=None, miss_send_len=None):
        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)


@_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 (0xffffffff if none).
    in_port          Packet's input port (OFPP_NONE if none).
    actions          ist of ``OFPAction*`` instance.
    data             Packet data of a binary type value or
                     an instances of packet.Packet.
    ================ ======================================================

    Example::

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

            buffer_id = 0xffffffff
            in_port = ofp.OFPP_NONE
            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):
        super(OFPPacketOut, self).__init__(datapath)
        self.buffer_id = buffer_id
        self.in_port = in_port
        self._actions_len = None
        self.actions = actions
        self.data = data

    def _serialize_body(self):
        assert self.buffer_id is not None
        assert self.in_port is not None
        assert self.actions is not None

        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
            if isinstance(self.data, packet.Packet):
                self.data.serialize()
                self.buf += self.data.data
            else:
                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)

    @classmethod
    def from_jsondict(cls, dict_, decode_string=base64.b64decode,
                      **additional_args):
        if isinstance(dict_['data'], dict):
            data = dict_.pop('data')
            ins = super(OFPPacketOut, cls).from_jsondict(dict_,
                                                         decode_string,
                                                         **additional_args)
            ins.data = packet.Packet.from_jsondict(data['Packet'])
            dict_['data'] = data
        else:
            ins = super(OFPPacketOut, cls).from_jsondict(dict_,
                                                         decode_string,
                                                         **additional_args)

        return ins


@_register_parser
@_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
    ================ ======================================================
    match            Instance of ``OFPMatch``.
    cookie           Opaque controller-issued identifier.
    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 0xffffffff).
                     Not meaningful for OFPFC_DELETE*.
    out_port         For OFPFC_DELETE* commands, require
                     matching entries to include this as an
                     output port. A value of OFPP_NONE
                     indicates no restriction.
    flags            One of the following values.

                     | OFPFF_SEND_FLOW_REM
                     | OFPFF_CHECK_OVERLAP
                     | OFPFF_EMERG
    actions          List of ``OFPAction*`` instance.
    ================ ======================================================

    Example::

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

            match = ofp_parser.OFPMatch(in_port=1)
            cookie = 0
            command = ofp.OFPFC_ADD
            idle_timeout = hard_timeout = 0
            priority = 32768
            buffer_id = 0xffffffff
            out_port = ofproto.OFPP_NONE
            flags = 0
            actions = [ofp_parser.OFPActionOutput(ofp.OFPP_NORMAL, 0)]
            req = ofp_parser.OFPFlowMod(
                datapath, match, cookie, command, idle_timeout, hard_timeout,
                priority, buffer_id, out_port, flags, actions)
            datapath.send_msg(req)
    """

    def __init__(self, datapath, match=None, cookie=0,
                 command=ofproto.OFPFC_ADD,
                 idle_timeout=0, hard_timeout=0,
                 priority=ofproto.OFP_DEFAULT_PRIORITY,
                 buffer_id=0xffffffff, out_port=ofproto.OFPP_NONE,
                 flags=0, actions=None):
        super(OFPFlowMod, self).__init__(datapath)
        self.match = OFPMatch() if match is None else match
        self.cookie = cookie
        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.flags = flags
        self.actions = [] if actions is None else actions

    def _serialize_body(self):
        offset = ofproto.OFP_HEADER_SIZE
        self.match.serialize(self.buf, offset)

        offset += ofproto.OFP_MATCH_SIZE
        msg_pack_into(ofproto.OFP_FLOW_MOD_PACK_STR0, self.buf, offset,
                      self.cookie, self.command,
                      self.idle_timeout, self.hard_timeout,
                      self.priority, self.buffer_id, self.out_port,
                      self.flags)

        offset = ofproto.OFP_FLOW_MOD_SIZE
        if self.actions is not None:
            for a in self.actions:
                a.serialize(self.buf, offset)
                offset += a.len

    @classmethod
    def parser(cls, datapath, version, msg_type, msg_len, xid, buf):
        msg = super(OFPFlowMod, cls).parser(
            datapath, version, msg_type, msg_len, xid, buf)
        offset = ofproto.OFP_HEADER_SIZE

        msg.match = OFPMatch.parse(msg.buf, offset)
        offset += ofproto.OFP_MATCH_SIZE

        (msg.cookie, msg.command, msg.idle_timeout, msg.hard_timeout,
         msg.priority, msg.buffer_id, msg.out_port,
         msg.flags) = struct.unpack_from(
            ofproto.OFP_FLOW_MOD_PACK_STR0, msg.buf, offset)
        offset = ofproto.OFP_FLOW_MOD_SIZE

        actions = []
        while offset < msg_len:
            a = OFPAction.parser(buf, offset)
            actions.append(a)
            offset += a.len
        msg.actions = actions

        return msg


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

    The controller send 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 ``OFPPhyPort`` of ``OFPSwitchFeatures``.
    config           Bitmap of configuration flags.

                     | OFPPC_PORT_DOWN
                     | OFPPC_NO_STP
                     | OFPPC_NO_RECV
                     | OFPPC_NO_RECV_STP
                     | OFPPC_NO_FLOOD
                     | 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_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_reply(OFPBarrierReply)
@_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)


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

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    port             Port to be queried. Should refer
                     to a valid physical port (i.e. < OFPP_MAX).
    ================ ======================================================

    Example::

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

            req = ofp_parser.OFPQueueGetConfigRequest(datapath,
                                                      ofp.OFPP_NONE)
            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 OFPStatsRequest(MsgBase):
    def __init__(self, datapath, flags):
        assert flags == 0       # none yet defined

        super(OFPStatsRequest, 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_STATS_MSG_PACK_STR,
                      self.buf, ofproto.OFP_HEADER_SIZE,
                      self.type, self.flags)
        self._serialize_stats_body()


@_set_msg_reply(OFPDescStatsReply)
@_set_stats_type(ofproto.OFPST_DESC, OFPDescStats)
@_set_msg_type(ofproto.OFPT_STATS_REQUEST)
class OFPDescStatsRequest(OFPStatsRequest):
    """
    Description statistics request message

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

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    flags            Zero (none yet defined in the spec).
    ================ ======================================================

    Example::

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

            req = ofp_parser.OFPDescStatsRequest(datapath)
            datapath.send_msg(req)
    """

    def __init__(self, datapath, flags):
        super(OFPDescStatsRequest, self).__init__(datapath, flags)


class OFPFlowStatsRequestBase(OFPStatsRequest):
    def __init__(self, datapath, flags, match, table_id, out_port):
        super(OFPFlowStatsRequestBase, self).__init__(datapath, flags)
        self.match = match
        self.table_id = table_id
        self.out_port = out_port

    def _serialize_stats_body(self):
        offset = ofproto.OFP_STATS_MSG_SIZE
        self.match.serialize(self.buf, offset)

        offset += ofproto.OFP_MATCH_SIZE
        msg_pack_into(ofproto.OFP_FLOW_STATS_REQUEST_ID_PORT_STR,
                      self.buf, offset, self.table_id, self.out_port)


@_set_msg_reply(OFPFlowStatsReply)
@_set_stats_type(ofproto.OFPST_FLOW, OFPFlowStats)
@_set_msg_type(ofproto.OFPT_STATS_REQUEST)
class OFPFlowStatsRequest(OFPFlowStatsRequestBase):
    """
    Individual flow statistics request message

    The controller uses this message to query individual flow statistics.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    flags            Zero (none yet defined in the spec).
    match            Instance of ``OFPMatch``.
    table_id         ID of table to read (from ofp_table_stats),
                     0xff for all tables or 0xfe for emergency.
    out_port         Require matching entries to include this
                     as an output port. A value of OFPP_NONE
                     indicates no restriction.
    ================ ======================================================

    Example::

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

            match = ofp_parser.OFPMatch(in_port=1)
            table_id = 0xff
            out_port = ofp.OFPP_NONE
            req = ofp_parser.OFPFlowStatsRequest(
                datapath, 0, match, table_id, out_port)

            datapath.send_msg(req)
    """

    def __init__(self, datapath, flags, match, table_id, out_port):
        super(OFPFlowStatsRequest, self).__init__(
            datapath, flags, match, table_id, out_port)


@_set_msg_reply(OFPAggregateStatsReply)
@_set_stats_type(ofproto.OFPST_AGGREGATE, OFPAggregateStats)
@_set_msg_type(ofproto.OFPT_STATS_REQUEST)
class OFPAggregateStatsRequest(OFPFlowStatsRequestBase):
    """
    Aggregate flow statistics request message

    The controller uses this message to query aggregate flow statictics.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    flags            Zero (none yet defined in the spec).
    match            Fields to match.
    table_id         ID of table to read (from ofp_table_stats)
                     0xff for all tables or 0xfe for emergency.
    out_port         Require matching entries to include this
                     as an output port. A value of OFPP_NONE
                     indicates no restriction.
    ================ ======================================================

    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, match, 0xff, ofp.OFPP_NONE)

            datapath.send_msg(req)
    """

    def __init__(self, datapath, flags, match, table_id, out_port):
        super(OFPAggregateStatsRequest, self).__init__(
            datapath, flags, match, table_id, out_port)


@_set_msg_reply(OFPTableStatsReply)
@_set_stats_type(ofproto.OFPST_TABLE, OFPTableStats)
@_set_msg_type(ofproto.OFPT_STATS_REQUEST)
class OFPTableStatsRequest(OFPStatsRequest):
    """
    Table statistics request message

    The controller uses this message to query flow table statictics.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    flags            Zero (none yet defined in the spec).
    ================ ======================================================

    Example::

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

            req = ofp_parser.OFPTableStatsRequest(datapath)
            datapath.send_msg(req)
    """

    def __init__(self, datapath, flags):
        super(OFPTableStatsRequest, self).__init__(datapath, flags)


@_set_msg_reply(OFPPortStatsReply)
@_set_stats_type(ofproto.OFPST_PORT, OFPPortStats)
@_set_msg_type(ofproto.OFPT_STATS_REQUEST)
class OFPPortStatsRequest(OFPStatsRequest):
    """
    Port statistics request message

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

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    flags            Zero (none yet defined in the spec).
    port_no          Port number to read (OFPP_NONE 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, port_no):
        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_STATS_MSG_SIZE, self.port_no)


@_set_msg_reply(OFPQueueStatsReply)
@_set_stats_type(ofproto.OFPST_QUEUE, OFPQueueStats)
@_set_msg_type(ofproto.OFPT_STATS_REQUEST)
class OFPQueueStatsRequest(OFPStatsRequest):
    """
    Queue statistics request message

    The controller uses this message to query queue statictics.

    ================ ======================================================
    Attribute        Description
    ================ ======================================================
    flags            Zero (none yet defined in the spec)
    port_no          Port number to read (All ports if OFPT_ALL).
    queue_id         ID of queue to read (All queues if OFPQ_ALL).
    ================ ======================================================

    Example::

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

            req = ofp_parser.OFPQueueStatsRequest(datapath, 0, ofp.OFPT_ALL,
                                                  ofp.OFPQ_ALL)
            datapath.send_msg(req)
    """

    def __init__(self, datapath, flags, port_no, queue_id):
        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_STATS_MSG_SIZE,
                      self.port_no, self.queue_id)


@_set_msg_reply(OFPVendorStatsReply)
@_set_stats_type(ofproto.OFPST_VENDOR, OFPVendorStats)
@_set_msg_type(ofproto.OFPT_STATS_REQUEST)
class OFPVendorStatsRequest(OFPStatsRequest):
    """
    Vendor statistics request message

    The controller uses this message to query vendor-specific information
    of a switch.
    """

    def __init__(self, datapath, flags, vendor, specific_data=None):
        super(OFPVendorStatsRequest, self).__init__(datapath, flags)
        self.vendor = vendor
        self.specific_data = specific_data

    def _serialize_vendor_stats(self):
        self.buf += self.specific_data

    def _serialize_stats_body(self):
        msg_pack_into(ofproto.OFP_VENDOR_STATS_MSG_PACK_STR,
                      self.buf, ofproto.OFP_STATS_MSG_SIZE,
                      self.vendor)
        self._serialize_vendor_stats()


class NXStatsRequest(OFPVendorStatsRequest):
    def __init__(self, datapath, flags, subtype):
        super(NXStatsRequest, self).__init__(datapath, flags,
                                             ofproto_common.NX_EXPERIMENTER_ID)
        self.subtype = subtype

    def _serialize_vendor_stats_body(self):
        pass

    def _serialize_vendor_stats(self):
        msg_pack_into(ofproto.NX_STATS_MSG_PACK_STR, self.buf,
                      ofproto.OFP_VENDOR_STATS_MSG_SIZE,
                      self.subtype)
        self._serialize_vendor_stats_body()


class NXFlowStatsRequest(NXStatsRequest):
    def __init__(self, datapath, flags, out_port, table_id, rule=None):
        super(NXFlowStatsRequest, self).__init__(datapath, flags,
                                                 ofproto.NXST_FLOW)
        self.out_port = out_port
        self.table_id = table_id
        self.rule = rule
        self.match_len = 0

    def _serialize_vendor_stats_body(self):
        if self.rule is not None:
            offset = ofproto.NX_STATS_MSG_SIZE + \
                ofproto.NX_FLOW_STATS_REQUEST_SIZE
            self.match_len = nx_match.serialize_nxm_match(
                self.rule, self.buf, offset)

        msg_pack_into(
            ofproto.NX_FLOW_STATS_REQUEST_PACK_STR,
            self.buf, ofproto.NX_STATS_MSG_SIZE, self.out_port,
            self.match_len, self.table_id)


class NXAggregateStatsRequest(NXStatsRequest):
    def __init__(self, datapath, flags, out_port, table_id, rule=None):
        super(NXAggregateStatsRequest, self).__init__(
            datapath, flags, ofproto.NXST_AGGREGATE)
        self.out_port = out_port
        self.table_id = table_id
        self.rule = rule
        self.match_len = 0

    def _serialize_vendor_stats_body(self):
        if self.rule is not None:
            offset = ofproto.NX_STATS_MSG_SIZE + \
                ofproto.NX_AGGREGATE_STATS_REQUEST_SIZE
            self.match_len = nx_match.serialize_nxm_match(
                self.rule, self.buf, offset)

        msg_pack_into(
            ofproto.NX_AGGREGATE_STATS_REQUEST_PACK_STR,
            self.buf, ofproto.NX_STATS_MSG_SIZE, self.out_port,
            self.match_len, self.table_id)


nx_actions.generate(
    'os_ken.ofproto.ofproto_v1_0',
    'os_ken.ofproto.ofproto_v1_0_parser'
)