mirror of https://github.com/morpheus65535/bazarr
151 lines
4.3 KiB
Python
151 lines
4.3 KiB
Python
# Copyright (C) 2009, 2011 Nominum, Inc.
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#
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# Permission to use, copy, modify, and distribute this software and its
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# documentation for any purpose with or without fee is hereby granted,
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# provided that the above copyright notice and this permission notice
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# appear in all copies.
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#
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# THE SOFTWARE IS PROVIDED "AS IS" AND NOMINUM DISCLAIMS ALL WARRANTIES
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# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM BE LIABLE FOR
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# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
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# OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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"""EDNS Options"""
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NSID = 3
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class Option(object):
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"""Base class for all EDNS option types.
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"""
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def __init__(self, otype):
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"""Initialize an option.
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@param otype: The rdata type
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@type otype: int
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"""
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self.otype = otype
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def to_wire(self, file):
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"""Convert an option to wire format.
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"""
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raise NotImplementedError
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@classmethod
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def from_wire(cls, otype, wire, current, olen):
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"""Build an EDNS option object from wire format
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@param otype: The option type
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@type otype: int
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@param wire: The wire-format message
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@type wire: string
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@param current: The offset in wire of the beginning of the rdata.
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@type current: int
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@param olen: The length of the wire-format option data
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@type olen: int
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@rtype: dns.edns.Option instance"""
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raise NotImplementedError
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def _cmp(self, other):
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"""Compare an EDNS option with another option of the same type.
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Return < 0 if self < other, 0 if self == other,
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and > 0 if self > other.
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"""
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raise NotImplementedError
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def __eq__(self, other):
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if not isinstance(other, Option):
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return False
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if self.otype != other.otype:
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return False
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return self._cmp(other) == 0
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def __ne__(self, other):
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if not isinstance(other, Option):
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return False
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if self.otype != other.otype:
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return False
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return self._cmp(other) != 0
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def __lt__(self, other):
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if not isinstance(other, Option) or \
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self.otype != other.otype:
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return NotImplemented
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return self._cmp(other) < 0
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def __le__(self, other):
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if not isinstance(other, Option) or \
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self.otype != other.otype:
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return NotImplemented
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return self._cmp(other) <= 0
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def __ge__(self, other):
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if not isinstance(other, Option) or \
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self.otype != other.otype:
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return NotImplemented
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return self._cmp(other) >= 0
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def __gt__(self, other):
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if not isinstance(other, Option) or \
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self.otype != other.otype:
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return NotImplemented
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return self._cmp(other) > 0
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class GenericOption(Option):
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"""Generate Rdata Class
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This class is used for EDNS option types for which we have no better
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implementation.
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"""
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def __init__(self, otype, data):
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super(GenericOption, self).__init__(otype)
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self.data = data
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def to_wire(self, file):
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file.write(self.data)
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@classmethod
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def from_wire(cls, otype, wire, current, olen):
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return cls(otype, wire[current: current + olen])
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def _cmp(self, other):
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if self.data == other.data:
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return 0
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if self.data > other.data:
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return 1
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return -1
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_type_to_class = {
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}
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def get_option_class(otype):
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cls = _type_to_class.get(otype)
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if cls is None:
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cls = GenericOption
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return cls
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def option_from_wire(otype, wire, current, olen):
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"""Build an EDNS option object from wire format
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@param otype: The option type
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@type otype: int
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@param wire: The wire-format message
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@type wire: string
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@param current: The offset in wire of the beginning of the rdata.
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@type current: int
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@param olen: The length of the wire-format option data
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@type olen: int
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@rtype: dns.edns.Option instance"""
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cls = get_option_class(otype)
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return cls.from_wire(otype, wire, current, olen)
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