Source code for pytomo.dns.rdtypes.mxbase

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"""MX-like base classes."""

from __future__ import absolute_import

import cStringIO
import struct

from .. import exception as dns_exception
from .. import rdata as dns_rdata
from .. import name as dns_name

[docs]class MXBase(dns_rdata.Rdata): """Base class for rdata that is like an MX record. @ivar preference: the preference value @type preference: int @ivar exchange: the exchange name @type exchange: dns_name.Name object""" __slots__ = ['preference', 'exchange'] def __init__(self, rdclass, rdtype, preference, exchange): super(MXBase, self).__init__(rdclass, rdtype) self.preference = preference self.exchange = exchange
[docs] def to_text(self, origin=None, relativize=True, **kw): exchange = self.exchange.choose_relativity(origin, relativize) return '%d %s' % (self.preference, exchange)
[docs] def from_text(cls, rdclass, rdtype, tok, origin = None, relativize = True): preference = tok.get_uint16() exchange = tok.get_name() exchange = exchange.choose_relativity(origin, relativize) tok.get_eol() return cls(rdclass, rdtype, preference, exchange)
from_text = classmethod(from_text)
[docs] def to_wire(self, file, compress = None, origin = None): pref = struct.pack("!H", self.preference) file.write(pref) self.exchange.to_wire(file, compress, origin)
[docs] def to_digestable(self, origin = None): return struct.pack("!H", self.preference) + \ self.exchange.to_digestable(origin)
[docs] def from_wire(cls, rdclass, rdtype, wire, current, rdlen, origin = None): (preference, ) = struct.unpack('!H', wire[current : current + 2]) current += 2 rdlen -= 2 (exchange, cused) = dns_name.from_wire(wire[: current + rdlen], current) if cused != rdlen: raise dns_exception.FormError if not origin is None: exchange = exchange.relativize(origin) return cls(rdclass, rdtype, preference, exchange)
from_wire = classmethod(from_wire)
[docs] def choose_relativity(self, origin = None, relativize = True): self.exchange = self.exchange.choose_relativity(origin, relativize)
def _cmp(self, other): sp = struct.pack("!H", self.preference) op = struct.pack("!H", other.preference) v = cmp(sp, op) if v == 0: v = cmp(self.exchange, other.exchange) return v
[docs]class UncompressedMX(MXBase): """Base class for rdata that is like an MX record, but whose name is not compressed when converted to DNS wire format, and whose digestable form is not downcased."""
[docs] def to_wire(self, file, compress = None, origin = None): super(UncompressedMX, self).to_wire(file, None, origin)
[docs] def to_digestable(self, origin = None): f = cStringIO.StringIO() self.to_wire(f, None, origin) return f.getvalue()
[docs]class UncompressedDowncasingMX(MXBase): """Base class for rdata that is like an MX record, but whose name is not compressed when convert to DNS wire format."""
[docs] def to_wire(self, file, compress = None, origin = None): super(UncompressedDowncasingMX, self).to_wire(file, None, origin)