Source code for pytomo.dns.rcode

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"""DNS Result Codes."""

from __future__ import absolute_import

from . import exception as 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()])


[docs]class UnknownRcode(dns_exception.DNSException): """Raised if an rcode is unknown.""" pass
[docs]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
[docs]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
[docs]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)
[docs]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