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# Copyright (C) 2017 Nippon Telegraph and Telephone Corporation.
#
# 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.
import struct
from ryu.lib import stringify
from . import packet_base
class openflow(packet_base.PacketBase):
"""OpenFlow message encoder/decoder class.
An instance has the following attributes at least.
============== =========================================================
Attribute Description
============== =========================================================
msg An instance of OpenFlow message (see :ref:`ofproto_ref`)
or an instance of OFPUnparseableMsg if failed to parse
packet as OpenFlow message.
============== =========================================================
"""
PACK_STR = '!BBHI'
_MIN_LEN = struct.calcsize(PACK_STR)
def __init__(self, msg):
super(openflow, self).__init__()
self.msg = msg
@classmethod
def parser(cls, buf):
from ryu.ofproto import ofproto_parser
from ryu.ofproto import ofproto_protocol
(version, msg_type, msg_len, xid) = ofproto_parser.header(buf)
msg_parser = ofproto_parser._MSG_PARSERS.get(version)
if msg_parser is None:
msg = OFPUnparseableMsg(
None, version, msg_type, msg_len, xid,
buf[cls._MIN_LEN:msg_len])
return cls(msg), cls, buf[msg_len:]
datapath = ofproto_protocol.ProtocolDesc(version=version)
try:
msg = msg_parser(datapath, version, msg_type, msg_len, xid,
buf[:msg_len])
except:
msg = OFPUnparseableMsg(
datapath, version, msg_type, msg_len, xid,
buf[datapath.ofproto.OFP_HEADER_SIZE:msg_len])
return cls(msg), cls, buf[msg_len:]
def serialize(self, _payload, _prev):
self.msg.serialize()
return self.msg.buf
class OFPUnparseableMsg(stringify.StringifyMixin):
"""Unparseable OpenFlow message encoder class.
An instance has the following attributes at least.
============== ======================================================
Attribute Description
============== ======================================================
datapath A ryu.ofproto.ofproto_protocol.ProtocolDesc instance
for this message or None if OpenFlow protocol version
is unsupported version.
version OpenFlow protocol version
msg_type Type of OpenFlow message
msg_len Length of the message
xid Transaction id
body OpenFlow body data
============== ======================================================
.. Note::
"datapath" attribute is different from
ryu.controller.controller.Datapath.
So you can not use "datapath" attribute to send OpenFlow messages.
For example, "datapath" attribute does not have send_msg method.
"""
def __init__(self, datapath, version, msg_type, msg_len, xid, body):
self.datapath = datapath
self.version = version
self.msg_type = msg_type
self.msg_len = msg_len
self.xid = xid
self.body = body
self.buf = None
def serialize(self):
self.buf = struct.pack(
openflow.PACK_STR,
self.version, self.msg_type, self.msg_len, self.xid)
self.buf += self.body
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