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