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# Copyright (C) 2016 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.
"""
Geneve packet parser/serializer
"""
import struct
from os_ken.lib import stringify
from os_ken.lib import type_desc
from . import packet_base
from . import ether_types
UDP_DST_PORT = 6081
class geneve(packet_base.PacketBase):
"""Geneve (RFC draft-ietf-nvo3-geneve-03) header encoder/decoder class.
An instance has the following attributes at least.
Most of them are same to the on-wire counterparts but in host byte order.
__init__ takes the corresponding args in this order.
============== ========================================================
Attribute Description
============== ========================================================
version Version.
opt_len The length of the options fields.
flags Flag field for OAM packet and Critical options present.
protocol Protocol Type field.
The Protocol Type is defined as "ETHER TYPES".
vni Identifier for unique element of virtual network.
options List of ``Option*`` instance.
============== ========================================================
"""
_HEADER_FMT = "!BBHI"
_MIN_LEN = struct.calcsize(_HEADER_FMT)
# 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
# +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
# |Ver| Opt Len |O|C| Rsvd. | Protocol Type |
# +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
# | Virtual Network Identifier (VNI) | Reserved |
# +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
# | Variable Length Options |
# +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
# Flags
OAM_PACKET_FLAG = 1 << 7
CRITICAL_OPTIONS_FLAG = 1 << 6
def __init__(self, version=0, opt_len=0, flags=0,
protocol=ether_types.ETH_TYPE_TEB, vni=None, options=None):
super(geneve, self).__init__()
self.version = version
self.opt_len = opt_len
assert (flags & 0x3F) == 0
self.flags = flags
self.protocol = protocol
self.vni = vni
for o in options:
assert isinstance(o, Option)
self.options = options
@classmethod
def parser(cls, buf):
(ver_opt_len, flags, protocol,
vni) = struct.unpack_from(cls._HEADER_FMT, buf)
version = ver_opt_len >> 6
# The Opt Len field expressed in four byte multiples.
opt_len = (ver_opt_len & 0x3F) * 4
opt_bin = buf[cls._MIN_LEN:cls._MIN_LEN + opt_len]
options = []
while opt_bin:
option, opt_bin = Option.parser(opt_bin)
options.append(option)
msg = cls(version, opt_len, flags, protocol, vni >> 8, options)
from . import ethernet
geneve._TYPES = ethernet.ethernet._TYPES
geneve.register_packet_type(ethernet.ethernet,
ether_types.ETH_TYPE_TEB)
return (msg, geneve.get_packet_type(protocol),
buf[cls._MIN_LEN + opt_len:])
def serialize(self, payload=None, prev=None):
tunnel_options = bytearray()
for o in self.options:
tunnel_options += o.serialize()
self.opt_len = len(tunnel_options)
# The Opt Len field expressed in four byte multiples.
opt_len = self.opt_len // 4
return (struct.pack(self._HEADER_FMT,
(self.version << 6) | opt_len,
self.flags, self.protocol, self.vni << 8)
+ tunnel_options)
class Option(stringify.StringifyMixin, type_desc.TypeDisp):
"""
Tunnel Options
"""
_OPTION_PACK_STR = "!HBB"
_OPTION_LEN = struct.calcsize(_OPTION_PACK_STR)
# 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
# +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
# | Option Class | Type |R|R|R| Length |
# +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
# | Variable Option Data |
# +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
def __init__(self, option_class=None, type_=None, length=0):
super(Option, self).__init__()
if option_class is None or type_ is None:
(option_class, type_) = self._rev_lookup_type(self.__class__)
self.option_class = option_class
self.type = type_
self.length = length
@classmethod
def parse_value(cls, buf):
# Sub-classes should override this method, if needed.
return {}
def serialize_value(self):
# Sub-classes should override this method, if needed.
return b''
@classmethod
def parser(cls, buf):
(option_class, type_,
length) = struct.unpack_from(cls._OPTION_PACK_STR, buf)
# The Length field expressed in four byte multiples.
length *= 4
subcls = Option._lookup_type((option_class, type_))
return (
subcls(option_class=option_class, type_=type_, length=length,
**subcls.parse_value(
buf[cls._OPTION_LEN:cls._OPTION_LEN + length])),
buf[cls._OPTION_LEN + length:])
def serialize(self, _payload=None, _prev=None):
data = self.serialize_value()
self.length = len(data)
# The Length field expressed in four byte multiples.
length = self.length // 4
return (struct.pack(self._OPTION_PACK_STR, int(self.option_class),
self.type, length) + data)
@Option.register_unknown_type()
class OptionDataUnknown(Option):
"""
Unknown Option Class and Type specific Option
"""
def __init__(self, buf, option_class=None, type_=None, length=0):
super(OptionDataUnknown, self).__init__(option_class=option_class,
type_=type_,
length=length)
self.buf = buf
@classmethod
def parse_value(cls, buf):
return {"buf": buf}
def serialize_value(self):
return self.buf
|
