loxi_ir.py

# Copyright 2013, Big Switch Networks, Inc.
#
# LoxiGen is licensed under the Eclipse Public License, version 1.0 (EPL), with
# the following special exception:
#
# LOXI Exception
#
# As a special exception to the terms of the EPL, you may distribute libraries
# generated by LoxiGen (LoxiGen Libraries) under the terms of your choice, provided
# that copyright and licensing notices generated by LoxiGen are not altered or removed
# from the LoxiGen Libraries and the notice provided below is (i) included in
# the LoxiGen Libraries, if distributed in source code form and (ii) included in any
# documentation for the LoxiGen Libraries, if distributed in binary form.
#
# Notice: "Copyright 2013, Big Switch Networks, Inc. This library was generated by the LoxiGen Compiler."
#
# You may not use this file except in compliance with the EPL or LOXI Exception. You may obtain
# a copy of the EPL at:
#
# http://www.eclipse.org/legal/epl-v10.html
#
# 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
# EPL for the specific language governing permissions and limitations
# under the EPL.

from generic_utils import find
from collections import namedtuple

# This module is intended to be imported like this: from loxi_ir import *
# All public names are prefixed with 'OF'.
__all__ = [
    'OFInput',
    'OFProtocol',
    'OFClass',
    'OFDataMember',
    'OFTypeMember',
    'OFDiscriminatorMember',
    'OFLengthMember',
    'OFFieldLengthMember',
    'OFPadMember',
    'OFEnum',
    'OFEnumEntry'
]

"""
One input file

@param wire_versions Set of integer wire versions this file applies to
@param classes List of OFClass objects in the same order as in the file
@param enums List of Enum objects in the same order as in the file
"""
OFInput = namedtuple('OFInput', ['wire_versions', 'classes', 'enums'])

"""
One version of the OpenFlow protocol

Combination of multiple OFInput objects.

@param wire_version
@param classes List of OFClass objects
@param enums List of Enum objects
"""
OFProtocol = namedtuple('OFProtocol', ['wire_version', 'classes', 'enums'])

"""
An OpenFlow class

All compound objects like messages, actions, instructions, etc are
uniformly represented by this class.

The members are in the same order as on the wire.

@param name
@param superclass name of the super class
@param members List of *Member objects
@param params optional dictionary of parameters
"""
class OFClass(namedtuple('OFClass', ['name', 'superclass', 'members', 'virtual', 'params'])):
    def member_by_name(self, name):
        return find(lambda m: hasattr(m, "name") and m.name == name, self.members)

    @property
    def discriminator(self):
        return find(lambda m: type(m) == OFDiscriminatorMember, self.members)

"""
Normal field

@param name
@param oftype C-like type string

Example: packet_in.buffer_id
"""
OFDataMember = namedtuple('OFDataMember', ['name', 'oftype'])

"""
Field that declares that this is an abstract super-class and
that the sub classes will be discriminated based on this field.
E.g., 'type' is the discriminator member of the abstract superclass
of_action.

@param name
"""
OFDiscriminatorMember = namedtuple('OFDiscriminatorMember', ['name', 'oftype'])

"""
Field used to determine the type of an OpenFlow object

@param name
@param oftype C-like type string
@param value Fixed type value

Example: packet_in.type, flow_add._command
"""
OFTypeMember = namedtuple('OFTypeMember', ['name', 'oftype', 'value'])

"""
Field with the length of the containing object

@param name
@param oftype C-like type string

Example: packet_in.length, action_output.len
"""
OFLengthMember = namedtuple('OFLengthMember', ['name', 'oftype'])

"""
Field with the length of another field in the containing object

@param name
@param oftype C-like type string
@param field_name Peer field whose length this field contains

Example: packet_out.actions_len (only usage)
"""
OFFieldLengthMember = namedtuple('OFFieldLengthMember', ['name', 'oftype', 'field_name'])

"""
Zero-filled padding

@param length Length in bytes

Example: packet_in.pad
"""
OFPadMember = namedtuple('OFPadMember', ['length'])

"""
An OpenFlow enumeration

All values are Python ints.

@param name
@param entries List of OFEnumEntry objects in input order
@params dict of optional params. Currently defined:
       - wire_type: the low_level type of the enum values (uint8,...)
"""
class OFEnum(namedtuple('OFEnum', ['name', 'entries', 'params'])):
    @property
    def values(self):
        return [(e.name, e.value) for e in self.entries]

    @property
    def is_bitmask(self):
        return "bitmask" in self.params and self.params['bitmask']


OFEnumEntry = namedtuple('OFEnumEntry', ['name', 'value', 'params'])