c92d8be079
Fix the f5d2157 commit. Signed-off-by: HIYAMA Manabu <hiyama.manabu@po.ntts.co.jp> Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
57 lines
2.0 KiB
Python
57 lines
2.0 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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import ipv4
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class udp(packet_base.PacketBase):
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_PACK_STR = '!HHHH'
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_MIN_LEN = struct.calcsize(_PACK_STR)
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def __init__(self, src_port, dst_port, total_length=0, csum=0):
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super(udp, self).__init__()
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self.src_port = src_port
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self.dst_port = dst_port
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self.total_length = total_length
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self.csum = csum
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self.length = udp._MIN_LEN
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@classmethod
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def parser(cls, buf):
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(src_port, dst_port, total_length, csum) = struct.unpack_from(
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cls._PACK_STR, buf)
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msg = cls(src_port, dst_port, total_length, csum)
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return msg, None
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def serialize(self, payload, prev):
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if self.total_length == 0:
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self.total_length = udp._MIN_LEN + len(payload)
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h = struct.pack(udp._PACK_STR, self.src_port, self.dst_port,
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self.total_length, self.csum)
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if self.csum == 0:
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ph = struct.pack('!IIBBH', prev.src, prev.dst, 0, 17,
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self.total_length)
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f = ph + h + payload
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if len(f) % 2:
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f += '\x00'
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self.csum = socket.htons(packet_utils.checksum(f))
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h = struct.pack(udp._PACK_STR, self.src_port, self.dst_port,
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self.total_length, self.csum)
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return h
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