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# Copyright (C) 2001-2007, 2009, 2010 Nominum, Inc.
#
# Permission to use, copy, modify, and distribute this software and its
# documentation for any purpose with or without fee is hereby granted,
# provided that the above copyright notice and this permission notice
# appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND NOMINUM DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM BE LIABLE FOR
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
# OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
"""DNS Result Codes."""
import dns.exception
NOERROR = 0
FORMERR = 1
SERVFAIL = 2
NXDOMAIN = 3
NOTIMP = 4
REFUSED = 5
YXDOMAIN = 6
YXRRSET = 7
NXRRSET = 8
NOTAUTH = 9
NOTZONE = 10
BADVERS = 16
_by_text = {
'NOERROR' : NOERROR,
'FORMERR' : FORMERR,
'SERVFAIL' : SERVFAIL,
'NXDOMAIN' : NXDOMAIN,
'NOTIMP' : NOTIMP,
'REFUSED' : REFUSED,
'YXDOMAIN' : YXDOMAIN,
'YXRRSET' : YXRRSET,
'NXRRSET' : NXRRSET,
'NOTAUTH' : NOTAUTH,
'NOTZONE' : NOTZONE,
'BADVERS' : BADVERS
}
# We construct the inverse mapping programmatically to ensure that we
# cannot make any mistakes (e.g. omissions, cut-and-paste errors) that
# would cause the mapping not to be a true inverse.
_by_value = dict([(y, x) for x, y in _by_text.iteritems()])
class UnknownRcode(dns.exception.DNSException):
"""Raised if an rcode is unknown."""
pass
def from_text(text):
"""Convert text into an rcode.
@param text: the texual rcode
@type text: string
@raises UnknownRcode: the rcode is unknown
@rtype: int
"""
if text.isdigit():
v = int(text)
if v >= 0 and v <= 4095:
return v
v = _by_text.get(text.upper())
if v is None:
raise UnknownRcode
return v
def from_flags(flags, ednsflags):
"""Return the rcode value encoded by flags and ednsflags.
@param flags: the DNS flags
@type flags: int
@param ednsflags: the EDNS flags
@type ednsflags: int
@raises ValueError: rcode is < 0 or > 4095
@rtype: int
"""
value = (flags & 0x000f) | ((ednsflags >> 20) & 0xff0)
if value < 0 or value > 4095:
raise ValueError('rcode must be >= 0 and <= 4095')
return value
def to_flags(value):
"""Return a (flags, ednsflags) tuple which encodes the rcode.
@param value: the rcode
@type value: int
@raises ValueError: rcode is < 0 or > 4095
@rtype: (int, int) tuple
"""
if value < 0 or value > 4095:
raise ValueError('rcode must be >= 0 and <= 4095')
v = value & 0xf
ev = long(value & 0xff0) << 20
return (v, ev)
def to_text(value):
"""Convert rcode into text.
@param value: the rcode
@type value: int
@rtype: string
"""
text = _by_value.get(value)
if text is None:
text = str(value)
return text
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