Current File : //usr/lib/python3/dist-packages/zeroconf/_utils/name.py
""" Multicast DNS Service Discovery for Python, v0.14-wmcbrine
Copyright 2003 Paul Scott-Murphy, 2014 William McBrine
This module provides a framework for the use of DNS Service Discovery
using IP multicast.
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301
USA
"""
from typing import Set
from .._exceptions import BadTypeInNameException
from ..const import (
_HAS_ASCII_CONTROL_CHARS,
_HAS_A_TO_Z,
_HAS_ONLY_A_TO_Z_NUM_HYPHEN,
_HAS_ONLY_A_TO_Z_NUM_HYPHEN_UNDERSCORE,
_LOCAL_TRAILER,
_NONTCP_PROTOCOL_LOCAL_TRAILER,
_TCP_PROTOCOL_LOCAL_TRAILER,
)
def service_type_name(type_: str, *, strict: bool = True) -> str: # pylint: disable=too-many-branches
"""
Validate a fully qualified service name, instance or subtype. [rfc6763]
Returns fully qualified service name.
Domain names used by mDNS-SD take the following forms:
<sn> . <_tcp|_udp> . local.
<Instance> . <sn> . <_tcp|_udp> . local.
<sub>._sub . <sn> . <_tcp|_udp> . local.
1) must end with 'local.'
This is true because we are implementing mDNS and since the 'm' means
multi-cast, the 'local.' domain is mandatory.
2) local is preceded with either '_udp.' or '_tcp.' unless
strict is False
3) service name <sn> precedes <_tcp|_udp> unless
strict is False
The rules for Service Names [RFC6335] state that they may be no more
than fifteen characters long (not counting the mandatory underscore),
consisting of only letters, digits, and hyphens, must begin and end
with a letter or digit, must not contain consecutive hyphens, and
must contain at least one letter.
The instance name <Instance> and sub type <sub> may be up to 63 bytes.
The portion of the Service Instance Name is a user-
friendly name consisting of arbitrary Net-Unicode text [RFC5198]. It
MUST NOT contain ASCII control characters (byte values 0x00-0x1F and
0x7F) [RFC20] but otherwise is allowed to contain any characters,
without restriction, including spaces, uppercase, lowercase,
punctuation -- including dots -- accented characters, non-Roman text,
and anything else that may be represented using Net-Unicode.
:param type_: Type, SubType or service name to validate
:return: fully qualified service name (eg: _http._tcp.local.)
"""
if len(type_) > 256:
# https://datatracker.ietf.org/doc/html/rfc6763#section-7.2
raise BadTypeInNameException("Full name (%s) must be > 256 bytes" % type_)
if type_.endswith((_TCP_PROTOCOL_LOCAL_TRAILER, _NONTCP_PROTOCOL_LOCAL_TRAILER)):
remaining = type_[: -len(_TCP_PROTOCOL_LOCAL_TRAILER)].split('.')
trailer = type_[-len(_TCP_PROTOCOL_LOCAL_TRAILER) :]
has_protocol = True
elif strict:
raise BadTypeInNameException(
"Type '%s' must end with '%s' or '%s'"
% (type_, _TCP_PROTOCOL_LOCAL_TRAILER, _NONTCP_PROTOCOL_LOCAL_TRAILER)
)
elif type_.endswith(_LOCAL_TRAILER):
remaining = type_[: -len(_LOCAL_TRAILER)].split('.')
trailer = type_[-len(_LOCAL_TRAILER) + 1 :]
has_protocol = False
else:
raise BadTypeInNameException(f"Type '{type_}' must end with '{_LOCAL_TRAILER}'")
if strict or has_protocol:
service_name = remaining.pop()
if not service_name:
raise BadTypeInNameException("No Service name found")
if len(remaining) == 1 and len(remaining[0]) == 0:
raise BadTypeInNameException("Type '%s' must not start with '.'" % type_)
if service_name[0] != '_':
raise BadTypeInNameException("Service name (%s) must start with '_'" % service_name)
test_service_name = service_name[1:]
if strict and len(test_service_name) > 15:
# https://datatracker.ietf.org/doc/html/rfc6763#section-7.2
raise BadTypeInNameException("Service name (%s) must be <= 15 bytes" % test_service_name)
if '--' in test_service_name:
raise BadTypeInNameException("Service name (%s) must not contain '--'" % test_service_name)
if '-' in (test_service_name[0], test_service_name[-1]):
raise BadTypeInNameException(
"Service name (%s) may not start or end with '-'" % test_service_name
)
if not _HAS_A_TO_Z.search(test_service_name):
raise BadTypeInNameException(
"Service name (%s) must contain at least one letter (eg: 'A-Z')" % test_service_name
)
allowed_characters_re = (
_HAS_ONLY_A_TO_Z_NUM_HYPHEN if strict else _HAS_ONLY_A_TO_Z_NUM_HYPHEN_UNDERSCORE
)
if not allowed_characters_re.search(test_service_name):
raise BadTypeInNameException(
"Service name (%s) must contain only these characters: "
"A-Z, a-z, 0-9, hyphen ('-')%s" % (test_service_name, "" if strict else ", underscore ('_')")
)
else:
service_name = ''
if remaining and remaining[-1] == '_sub':
remaining.pop()
if len(remaining) == 0 or len(remaining[0]) == 0:
raise BadTypeInNameException("_sub requires a subtype name")
if len(remaining) > 1:
remaining = ['.'.join(remaining)]
if remaining:
length = len(remaining[0].encode('utf-8'))
if length > 63:
raise BadTypeInNameException("Too long: '%s'" % remaining[0])
if _HAS_ASCII_CONTROL_CHARS.search(remaining[0]):
raise BadTypeInNameException(
"Ascii control character 0x00-0x1F and 0x7F illegal in '%s'" % remaining[0]
)
return service_name + trailer
def possible_types(name: str) -> Set[str]:
"""Build a set of all possible types from a fully qualified name."""
labels = name.split('.')
label_count = len(labels)
types = set()
for count in range(label_count):
parts = labels[label_count - count - 4 :]
if not parts[0].startswith('_'):
break
types.add('.'.join(parts))
return types
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