c42673def1
Signed-off-by: HIYAMA Manabu <hiyama.manabu@po.ntts.co.jp> Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
86 lines
3.0 KiB
Python
86 lines
3.0 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 struct
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import socket
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from . import packet_base
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from . import packet_utils
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from . import icmp
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from . import udp
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from . import tcp
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from ryu.ofproto import inet
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class ipv4(packet_base.PacketBase):
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_PACK_STR = '!BBHHHBBHII'
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_MIN_LEN = struct.calcsize(_PACK_STR)
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def __init__(self, version, header_length, tos, total_length,
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identification, flags, offset, ttl, proto, csum,
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src, dst, option=None):
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super(ipv4, self).__init__()
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self.version = version
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self.header_length = header_length
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self.tos = tos
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self.total_length = total_length
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self.identification = identification
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self.flags = flags
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self.offset = offset
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self.ttl = ttl
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self.proto = proto
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self.csum = csum
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self.src = src
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self.dst = dst
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self.length = header_length * 4
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self.option = option
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@classmethod
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def parser(cls, buf):
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(version, tos, total_length, identification, flags, ttl, proto, csum,
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src, dst) = struct.unpack_from(cls._PACK_STR, buf)
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header_length = version & 0xf
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version = version >> 4
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offset = flags & ((1 << 13) - 1)
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flags = flags >> 13
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msg = cls(version, header_length, tos, total_length, identification,
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flags, offset, ttl, proto, csum, src, dst)
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if msg.length > ipv4._MIN_LEN:
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msg.option = buf[ipv4._MIN_LEN:msg.length]
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return msg, ipv4.get_packet_type(proto)
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def serialize(self, payload, prev):
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hdr = bytearray(self.header_length * 4)
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version = self.version << 4 | self.header_length
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flags = self.flags << 13 | self.offset
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if self.total_length == 0:
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self.total_length = self.header_length * 4 + len(payload)
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struct.pack_into(ipv4._PACK_STR, hdr, 0, version, self.tos,
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self.total_length, self.identification, flags,
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self.ttl, self.proto, 0, self.src, self.dst)
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if self.option:
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assert (self.length - ipv4._MIN_LEN) >= len(self.option)
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hdr[ipv4._MIN_LEN:ipv4._MIN_LEN + len(self.option)] = self.option
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self.csum = socket.htons(packet_utils.checksum(hdr))
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struct.pack_into('!H', hdr, 10, self.csum)
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return hdr
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ipv4.register_packet_type(icmp.icmp, inet.IPPROTO_ICMP)
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ipv4.register_packet_type(tcp.tcp, inet.IPPROTO_TCP)
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ipv4.register_packet_type(udp.udp, inet.IPPROTO_UDP)
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