131 lines
4.3 KiB
Python
131 lines
4.3 KiB
Python
# Copyright (C) 2012 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 abc
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import six
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import struct
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from . import packet_base
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from . import arp
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from . import ipv4
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from . import ipv6
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from . import lldp
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from . import slow
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from . import llc
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from . import pbb
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from . import cfm
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from . import ether_types as ether
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@six.add_metaclass(abc.ABCMeta)
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class _vlan(packet_base.PacketBase):
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_PACK_STR = "!HH"
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_MIN_LEN = struct.calcsize(_PACK_STR)
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@abc.abstractmethod
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def __init__(self, pcp, cfi, vid, ethertype):
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super(_vlan, self).__init__()
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self.pcp = pcp
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self.cfi = cfi
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self.vid = vid
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self.ethertype = ethertype
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@classmethod
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def parser(cls, buf):
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tci, ethertype = struct.unpack_from(cls._PACK_STR, buf)
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pcp = tci >> 13
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cfi = (tci >> 12) & 1
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vid = tci & ((1 << 12) - 1)
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return (cls(pcp, cfi, vid, ethertype),
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vlan.get_packet_type(ethertype), buf[vlan._MIN_LEN:])
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def serialize(self, payload, prev):
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tci = self.pcp << 13 | self.cfi << 12 | self.vid
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return struct.pack(vlan._PACK_STR, tci, self.ethertype)
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class vlan(_vlan):
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"""VLAN (IEEE 802.1Q) 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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pcp Priority Code Point
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cfi Canonical Format Indicator
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vid VLAN Identifier
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ethertype EtherType
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============== ====================
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"""
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def __init__(self, pcp=0, cfi=0, vid=0, ethertype=ether.ETH_TYPE_IP):
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super(vlan, self).__init__(pcp, cfi, vid, ethertype)
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@classmethod
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def get_packet_type(cls, type_):
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"""Override method for the Length/Type field (self.ethertype).
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The Length/Type field means Length or Type interpretation,
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same as ethernet IEEE802.3.
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If the value of Length/Type field is less than or equal to
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1500 decimal(05DC hexadecimal), it means Length interpretation
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and be passed to the LLC sublayer."""
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if type_ <= ether.ETH_TYPE_IEEE802_3:
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type_ = ether.ETH_TYPE_IEEE802_3
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return cls._TYPES.get(type_)
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class svlan(_vlan):
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"""S-VLAN (IEEE 802.1ad) 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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.. tabularcolumns:: |l|L|
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============== ====================
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Attribute Description
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============== ====================
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pcp Priority Code Point
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cfi Canonical Format Indicator.
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In a case to be used as B-TAG,
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this field means DEI(Drop Eligible Indication).
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vid VLAN Identifier
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ethertype EtherType
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============== ====================
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"""
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def __init__(self, pcp=0, cfi=0, vid=0, ethertype=ether.ETH_TYPE_8021Q):
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super(svlan, self).__init__(pcp, cfi, vid, ethertype)
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@classmethod
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def get_packet_type(cls, type_):
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return cls._TYPES.get(type_)
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vlan.register_packet_type(arp.arp, ether.ETH_TYPE_ARP)
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vlan.register_packet_type(ipv4.ipv4, ether.ETH_TYPE_IP)
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vlan.register_packet_type(ipv6.ipv6, ether.ETH_TYPE_IPV6)
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vlan.register_packet_type(lldp.lldp, ether.ETH_TYPE_LLDP)
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vlan.register_packet_type(slow.slow, ether.ETH_TYPE_SLOW)
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vlan.register_packet_type(llc.llc, ether.ETH_TYPE_IEEE802_3)
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vlan.register_packet_type(cfm.cfm, ether.ETH_TYPE_CFM)
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svlan.register_packet_type(vlan, ether.ETH_TYPE_8021Q)
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svlan.register_packet_type(pbb.itag, ether.ETH_TYPE_8021AH)
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