94 lines
2.9 KiB
Python
94 lines
2.9 KiB
Python
# Copyright (C) 2016 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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import logging
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import six
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from . import packet_base
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from os_ken.lib import type_desc
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LOG = logging.getLogger(__name__)
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UDP_DST_PORT = 4789
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UDP_DST_PORT_OLD = 8472 # for backward compatibility like Linux
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class vxlan(packet_base.PacketBase):
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"""VXLAN (RFC 7348) header encoder/decoder class.
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An instance has the following attributes at least.
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Most of them are same to the on-wire counterparts but in host byte order.
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__init__ takes the corresponding args in this order.
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============== ====================
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Attribute Description
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============== ====================
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vni VXLAN Network Identifier
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============== ====================
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"""
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# Note: Python has no format character for 24 bits field.
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# we use uint32 format character instead and bit-shift at serializing.
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_PACK_STR = '!II'
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_MIN_LEN = struct.calcsize(_PACK_STR)
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# VXLAN Header:
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# +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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# |R|R|R|R|I|R|R|R| Reserved |
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# +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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# | VXLAN Network Identifier (VNI) | Reserved |
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# +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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def __init__(self, vni):
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super(vxlan, self).__init__()
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self.vni = vni
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@classmethod
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def parser(cls, buf):
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(flags_reserved, vni_rserved) = struct.unpack_from(cls._PACK_STR, buf)
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# Check VXLAN flags is valid
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assert (1 << 3) == (flags_reserved >> 24)
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# Note: To avoid cyclic import, import ethernet module here
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from os_ken.lib.packet import ethernet
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return cls(vni_rserved >> 8), ethernet.ethernet, buf[cls._MIN_LEN:]
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def serialize(self, payload, prev):
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return struct.pack(self._PACK_STR,
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1 << (3 + 24), self.vni << 8)
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def vni_from_bin(buf):
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"""
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Converts binary representation VNI to integer.
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:param buf: binary representation of VNI.
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:return: VNI integer.
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"""
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return type_desc.Int3.to_user(six.binary_type(buf))
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def vni_to_bin(vni):
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"""
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Converts integer VNI to binary representation.
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:param vni: integer of VNI
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:return: binary representation of VNI.
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"""
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return type_desc.Int3.from_user(vni)
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