1# Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license
2
3# Copyright (C) 2006-2017 Nominum, Inc.
4#
5# Permission to use, copy, modify, and distribute this software and its
6# documentation for any purpose with or without fee is hereby granted,
7# provided that the above copyright notice and this permission notice
8# appear in all copies.
9#
10# THE SOFTWARE IS PROVIDED "AS IS" AND NOMINUM DISCLAIMS ALL WARRANTIES
11# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM BE LIABLE FOR
13# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
16# OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17
18"""DNS E.164 helpers."""
19
20import dns.exception
21import dns.name
22import dns.resolver
23from ._compat import string_types, maybe_decode
24
25#: The public E.164 domain.
26public_enum_domain = dns.name.from_text('e164.arpa.')
27
28
29def from_e164(text, origin=public_enum_domain):
30    """Convert an E.164 number in textual form into a Name object whose
31    value is the ENUM domain name for that number.
32
33    Non-digits in the text are ignored, i.e. "16505551212",
34    "+1.650.555.1212" and "1 (650) 555-1212" are all the same.
35
36    *text*, a ``text``, is an E.164 number in textual form.
37
38    *origin*, a ``dns.name.Name``, the domain in which the number
39    should be constructed.  The default is ``e164.arpa.``.
40
41    Returns a ``dns.name.Name``.
42    """
43
44    parts = [d for d in text if d.isdigit()]
45    parts.reverse()
46    return dns.name.from_text('.'.join(parts), origin=origin)
47
48
49def to_e164(name, origin=public_enum_domain, want_plus_prefix=True):
50    """Convert an ENUM domain name into an E.164 number.
51
52    Note that dnspython does not have any information about preferred
53    number formats within national numbering plans, so all numbers are
54    emitted as a simple string of digits, prefixed by a '+' (unless
55    *want_plus_prefix* is ``False``).
56
57    *name* is a ``dns.name.Name``, the ENUM domain name.
58
59    *origin* is a ``dns.name.Name``, a domain containing the ENUM
60    domain name.  The name is relativized to this domain before being
61    converted to text.  If ``None``, no relativization is done.
62
63    *want_plus_prefix* is a ``bool``.  If True, add a '+' to the beginning of
64    the returned number.
65
66    Returns a ``text``.
67
68    """
69    if origin is not None:
70        name = name.relativize(origin)
71    dlabels = [d for d in name.labels if d.isdigit() and len(d) == 1]
72    if len(dlabels) != len(name.labels):
73        raise dns.exception.SyntaxError('non-digit labels in ENUM domain name')
74    dlabels.reverse()
75    text = b''.join(dlabels)
76    if want_plus_prefix:
77        text = b'+' + text
78    return maybe_decode(text)
79
80
81def query(number, domains, resolver=None):
82    """Look for NAPTR RRs for the specified number in the specified domains.
83
84    e.g. lookup('16505551212', ['e164.dnspython.org.', 'e164.arpa.'])
85
86    *number*, a ``text`` is the number to look for.
87
88    *domains* is an iterable containing ``dns.name.Name`` values.
89
90    *resolver*, a ``dns.resolver.Resolver``, is the resolver to use.  If
91    ``None``, the default resolver is used.
92    """
93
94    if resolver is None:
95        resolver = dns.resolver.get_default_resolver()
96    e_nx = dns.resolver.NXDOMAIN()
97    for domain in domains:
98        if isinstance(domain, string_types):
99            domain = dns.name.from_text(domain)
100        qname = dns.e164.from_e164(number, domain)
101        try:
102            return resolver.query(qname, 'NAPTR')
103        except dns.resolver.NXDOMAIN as e:
104            e_nx += e
105    raise e_nx
106