298 lines
9.1 KiB
Python
298 lines
9.1 KiB
Python
# Copyright (C) 2011, 2012 Nippon Telegraph and Telephone Corporation.
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# Copyright (C) 2011 Isaku Yamahata <yamahata at valinux co jp>
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
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# implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import six
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import base64
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import collections
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import logging
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import struct
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import functools
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from os_ken import exception
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from os_ken import utils
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from os_ken.lib import stringify
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from os_ken.ofproto import ofproto_common
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LOG = logging.getLogger('os_ken.ofproto.ofproto_parser')
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# This is merely for API compatibility on python2
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if six.PY3:
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buffer = bytes
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def header(buf):
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assert len(buf) >= ofproto_common.OFP_HEADER_SIZE
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# LOG.debug('len %d bufsize %d', len(buf), ofproto.OFP_HEADER_SIZE)
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return struct.unpack_from(ofproto_common.OFP_HEADER_PACK_STR,
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six.binary_type(buf))
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_MSG_PARSERS = {}
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def register_msg_parser(version):
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def register(msg_parser):
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_MSG_PARSERS[version] = msg_parser
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return msg_parser
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return register
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def msg(datapath, version, msg_type, msg_len, xid, buf):
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exp = None
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try:
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assert len(buf) >= msg_len
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except AssertionError as e:
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exp = e
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msg_parser = _MSG_PARSERS.get(version)
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if msg_parser is None:
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raise exception.OFPUnknownVersion(version=version)
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try:
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msg = msg_parser(datapath, version, msg_type, msg_len, xid, buf)
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except exception.OFPTruncatedMessage as e:
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raise e
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except:
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LOG.exception(
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'Encountered an error while parsing OpenFlow packet from switch. '
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'This implies the switch sent a malformed OpenFlow packet. '
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'version 0x%02x msg_type %d msg_len %d xid %d buf %s',
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version, msg_type, msg_len, xid, utils.hex_array(buf))
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msg = None
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if exp:
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raise exp
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return msg
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def create_list_of_base_attributes(f):
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@functools.wraps(f)
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def wrapper(self, *args, **kwargs):
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ret = f(self, *args, **kwargs)
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cls = self.__class__
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# hasattr(cls, '_base_attributes') doesn't work because super class
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# may already have the attribute.
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if '_base_attributes' not in cls.__dict__:
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cls._base_attributes = set(dir(self))
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return ret
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return wrapper
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def ofp_msg_from_jsondict(dp, jsondict):
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"""
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This function instanticates an appropriate OpenFlow message class
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from the given JSON style dictionary.
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The objects created by following two code fragments are equivalent.
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Code A::
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jsonstr = '{ "OFPSetConfig": { "flags": 0, "miss_send_len": 128 } }'
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jsondict = json.loads(jsonstr)
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o = ofp_msg_from_jsondict(dp, jsondict)
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Code B::
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o = dp.ofproto_parser.OFPSetConfig(flags=0, miss_send_len=128)
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This function takes the following arguments.
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======== =======================================
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Argument Description
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======== =======================================
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dp An instance of os_ken.controller.Datapath.
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jsondict A JSON style dict.
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======== =======================================
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"""
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parser = dp.ofproto_parser
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assert len(jsondict) == 1
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for k, v in jsondict.items():
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cls = getattr(parser, k)
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assert issubclass(cls, MsgBase)
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return cls.from_jsondict(v, datapath=dp)
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def ofp_instruction_from_jsondict(dp, jsonlist, encap=True):
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"""
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This function is intended to be used with
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os_ken.lib.ofctl_string.ofp_instruction_from_str.
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It is very similar to ofp_msg_from_jsondict, but works on
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a list of OFPInstructions/OFPActions. It also encapsulates
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OFPAction into OFPInstructionActions, as >OF1.0 OFPFlowMod
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requires that.
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This function takes the following arguments.
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======== ==================================================
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Argument Description
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======== ==================================================
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dp An instance of os_ken.controller.Datapath.
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jsonlist A list of JSON style dictionaries.
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encap Encapsulate OFPAction into OFPInstructionActions.
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Must be false for OF10.
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======== ==================================================
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"""
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proto = dp.ofproto
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parser = dp.ofproto_parser
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actions = []
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result = []
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for jsondict in jsonlist:
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assert len(jsondict) == 1
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k, v = list(jsondict.items())[0]
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cls = getattr(parser, k)
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if issubclass(cls, parser.OFPAction):
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if encap:
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actions.append(cls.from_jsondict(v))
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continue
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else:
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ofpinst = getattr(parser, 'OFPInstruction', None)
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if not ofpinst or not issubclass(cls, ofpinst):
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raise ValueError("Supplied jsondict is of wrong type: %s",
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jsondict)
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result.append(cls.from_jsondict(v))
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if not encap:
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return result
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if actions:
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# Although the OpenFlow spec says Apply Actions is executed first,
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# let's place it in the head as a precaution.
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result = [parser.OFPInstructionActions(
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proto.OFPIT_APPLY_ACTIONS, actions)] + result
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return result
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class StringifyMixin(stringify.StringifyMixin):
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_class_prefixes = ["OFP", "ONF", "MT", "NX"]
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@classmethod
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def cls_from_jsondict_key(cls, k):
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obj_cls = super(StringifyMixin, cls).cls_from_jsondict_key(k)
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return obj_cls
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class MsgBase(StringifyMixin):
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"""
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This is a base class for OpenFlow message classes.
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An instance of this class has at least the following attributes.
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========= ==============================
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Attribute Description
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========= ==============================
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datapath A os_ken.controller.controller.Datapath instance for this message
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version OpenFlow protocol version
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msg_type Type of OpenFlow message
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msg_len Length of the message
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xid Transaction id
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buf Raw data
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========= ==============================
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"""
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@create_list_of_base_attributes
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def __init__(self, datapath):
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super(MsgBase, self).__init__()
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self.datapath = datapath
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self.version = None
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self.msg_type = None
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self.msg_len = None
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self.xid = None
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self.buf = None
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def set_headers(self, version, msg_type, msg_len, xid):
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assert msg_type == self.cls_msg_type
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self.version = version
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self.msg_type = msg_type
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self.msg_len = msg_len
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self.xid = xid
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def set_xid(self, xid):
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assert self.xid is None
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self.xid = xid
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def set_buf(self, buf):
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self.buf = buffer(buf)
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def __str__(self):
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def hexify(x):
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return hex(x) if isinstance(x, six.integer_types) else x
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buf = 'version=%s,msg_type=%s,msg_len=%s,xid=%s,' %\
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(hexify(self.version), hexify(self.msg_type),
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hexify(self.msg_len), hexify(self.xid))
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return buf + StringifyMixin.__str__(self)
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@classmethod
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def parser(cls, datapath, version, msg_type, msg_len, xid, buf):
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msg_ = cls(datapath)
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msg_.set_headers(version, msg_type, msg_len, xid)
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msg_.set_buf(buf)
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return msg_
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def _serialize_pre(self):
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self.version = self.datapath.ofproto.OFP_VERSION
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self.msg_type = self.cls_msg_type
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self.buf = bytearray(self.datapath.ofproto.OFP_HEADER_SIZE)
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def _serialize_header(self):
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# buffer length is determined after trailing data is formated.
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assert self.version is not None
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assert self.msg_type is not None
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assert self.buf is not None
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assert len(self.buf) >= self.datapath.ofproto.OFP_HEADER_SIZE
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self.msg_len = len(self.buf)
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if self.xid is None:
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self.xid = 0
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struct.pack_into(self.datapath.ofproto.OFP_HEADER_PACK_STR,
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self.buf, 0,
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self.version, self.msg_type, self.msg_len, self.xid)
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def _serialize_body(self):
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pass
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def serialize(self):
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self._serialize_pre()
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self._serialize_body()
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self._serialize_header()
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class MsgInMsgBase(MsgBase):
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@classmethod
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def _decode_value(cls, k, json_value, decode_string=base64.b64decode,
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**additional_args):
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return cls._get_decoder(k, decode_string)(json_value,
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**additional_args)
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def namedtuple(typename, fields, **kwargs):
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class _namedtuple(StringifyMixin,
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collections.namedtuple(typename, fields, **kwargs)):
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pass
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return _namedtuple
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def msg_str_attr(msg_, buf, attr_list=None):
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if attr_list is None:
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attr_list = stringify.obj_attrs(msg_)
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for attr in attr_list:
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val = getattr(msg_, attr, None)
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if val is not None:
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buf += ' %s %s' % (attr, val)
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return buf
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