# Wrapper module for _ssl, providing some additional facilities
	# implemented in Python. Written by Bill Janssen.
	"""This module provides some more Pythonic support for SSL.
	Object types:
	SSLSocket -- subtype of socket.socket which does SSL over the socket
	Exceptions:
	SSLError -- exception raised for I/O errors
	Functions:
	cert_time_to_seconds -- convert time string used for certificate
	notBefore and notAfter functions to integer
	seconds past the Epoch (the time values
	returned from time.time())
	fetch_server_certificate (HOST, PORT) -- fetch the certificate provided
	by the server running on HOST at port PORT. No
	validation of the certificate is performed.
	Integer constants:
	SSL_ERROR_ZERO_RETURN
	SSL_ERROR_WANT_READ
	SSL_ERROR_WANT_WRITE
	SSL_ERROR_WANT_X509_LOOKUP
	SSL_ERROR_SYSCALL
	SSL_ERROR_SSL
	SSL_ERROR_WANT_CONNECT
	SSL_ERROR_EOF
	SSL_ERROR_INVALID_ERROR_CODE
	The following group define certificate requirements that one side is
	allowing/requiring from the other side:
	CERT_NONE - no certificates from the other side are required (or will
	be looked at if provided)
	CERT_OPTIONAL - certificates are not required, but if provided will be
	validated, and if validation fails, the connection will
	also fail
	CERT_REQUIRED - certificates are required, and will be validated, and
	if validation fails, the connection will also fail
	The following constants identify various SSL protocol variants:
	PROTOCOL_SSLv2
	PROTOCOL_SSLv3
	PROTOCOL_SSLv23
	PROTOCOL_TLS
	PROTOCOL_TLS_CLIENT
	PROTOCOL_TLS_SERVER
	PROTOCOL_TLSv1
	PROTOCOL_TLSv1_1
	PROTOCOL_TLSv1_2
	The following constants identify various SSL alert message descriptions as per
	http://www.iana.org/assignments/tls-parameters/tls-parameters.xml#tls-parameters-6
	ALERT_DESCRIPTION_CLOSE_NOTIFY
	ALERT_DESCRIPTION_UNEXPECTED_MESSAGE
	ALERT_DESCRIPTION_BAD_RECORD_MAC
	ALERT_DESCRIPTION_RECORD_OVERFLOW
	ALERT_DESCRIPTION_DECOMPRESSION_FAILURE
	ALERT_DESCRIPTION_HANDSHAKE_FAILURE
	ALERT_DESCRIPTION_BAD_CERTIFICATE
	ALERT_DESCRIPTION_UNSUPPORTED_CERTIFICATE
	ALERT_DESCRIPTION_CERTIFICATE_REVOKED
	ALERT_DESCRIPTION_CERTIFICATE_EXPIRED
	ALERT_DESCRIPTION_CERTIFICATE_UNKNOWN
	ALERT_DESCRIPTION_ILLEGAL_PARAMETER
	ALERT_DESCRIPTION_UNKNOWN_CA
	ALERT_DESCRIPTION_ACCESS_DENIED
	ALERT_DESCRIPTION_DECODE_ERROR
	ALERT_DESCRIPTION_DECRYPT_ERROR
	ALERT_DESCRIPTION_PROTOCOL_VERSION
	ALERT_DESCRIPTION_INSUFFICIENT_SECURITY
	ALERT_DESCRIPTION_INTERNAL_ERROR
	ALERT_DESCRIPTION_USER_CANCELLED
	ALERT_DESCRIPTION_NO_RENEGOTIATION
	ALERT_DESCRIPTION_UNSUPPORTED_EXTENSION
	ALERT_DESCRIPTION_CERTIFICATE_UNOBTAINABLE
	ALERT_DESCRIPTION_UNRECOGNIZED_NAME
	ALERT_DESCRIPTION_BAD_CERTIFICATE_STATUS_RESPONSE
	ALERT_DESCRIPTION_BAD_CERTIFICATE_HASH_VALUE
	ALERT_DESCRIPTION_UNKNOWN_PSK_IDENTITY
	"""
	import sys
	import os
	from collections import namedtuple
	from enum import Enum as _Enum, IntEnum as _IntEnum, IntFlag as _IntFlag
	import _ssl # if we can't import it, let the error propagate
	from _ssl import OPENSSL_VERSION_NUMBER, OPENSSL_VERSION_INFO, OPENSSL_VERSION
	from _ssl import _SSLContext, MemoryBIO, SSLSession
	from _ssl import (
	SSLError, SSLZeroReturnError, SSLWantReadError, SSLWantWriteError,
	SSLSyscallError, SSLEOFError, SSLCertVerificationError
	)
	from _ssl import txt2obj as _txt2obj, nid2obj as _nid2obj
	from _ssl import RAND_status, RAND_add, RAND_bytes, RAND_pseudo_bytes
	try:
	from _ssl import RAND_egd
	except ImportError:
	# LibreSSL does not provide RAND_egd
	pass
	from _ssl import (
	HAS_SNI, HAS_ECDH, HAS_NPN, HAS_ALPN, HAS_SSLv2, HAS_SSLv3, HAS_TLSv1,
	HAS_TLSv1_1, HAS_TLSv1_2, HAS_TLSv1_3
	)
	from _ssl import _DEFAULT_CIPHERS, _OPENSSL_API_VERSION
	_IntEnum._convert(
	'_SSLMethod', __name__,
	lambda name: name.startswith('PROTOCOL_') and name != 'PROTOCOL_SSLv23',
	source=_ssl)
	_IntFlag._convert(
	'Options', __name__,
	lambda name: name.startswith('OP_'),
	source=_ssl)
	_IntEnum._convert(
	'AlertDescription', __name__,
	lambda name: name.startswith('ALERT_DESCRIPTION_'),
	source=_ssl)
	_IntEnum._convert(
	'SSLErrorNumber', __name__,
	lambda name: name.startswith('SSL_ERROR_'),
	source=_ssl)
	_IntFlag._convert(
	'VerifyFlags', __name__,
	lambda name: name.startswith('VERIFY_'),
	source=_ssl)
	_IntEnum._convert(
	'VerifyMode', __name__,
	lambda name: name.startswith('CERT_'),
	source=_ssl)
	PROTOCOL_SSLv23 = _SSLMethod.PROTOCOL_SSLv23 = _SSLMethod.PROTOCOL_TLS
	_PROTOCOL_NAMES = {value: name for name, value in _SSLMethod.__members__.items()}
	_SSLv2_IF_EXISTS = getattr(_SSLMethod, 'PROTOCOL_SSLv2', None)
	class TLSVersion(_IntEnum):
	MINIMUM_SUPPORTED = _ssl.PROTO_MINIMUM_SUPPORTED
	SSLv3 = _ssl.PROTO_SSLv3
	TLSv1 = _ssl.PROTO_TLSv1
	TLSv1_1 = _ssl.PROTO_TLSv1_1
	TLSv1_2 = _ssl.PROTO_TLSv1_2
	TLSv1_3 = _ssl.PROTO_TLSv1_3
	MAXIMUM_SUPPORTED = _ssl.PROTO_MAXIMUM_SUPPORTED
	if sys.platform == "win32":
	from _ssl import enum_certificates, enum_crls
	from socket import socket, AF_INET, SOCK_STREAM, create_connection
	from socket import SOL_SOCKET, SO_TYPE
	import socket as _socket
	import base64 # for DER-to-PEM translation
	import errno
	import warnings
	socket_error = OSError # keep that public name in module namespace
	CHANNEL_BINDING_TYPES = ['tls-unique']
	HAS_NEVER_CHECK_COMMON_NAME = hasattr(_ssl, 'HOSTFLAG_NEVER_CHECK_SUBJECT')
	_RESTRICTED_SERVER_CIPHERS = _DEFAULT_CIPHERS
	CertificateError = SSLCertVerificationError
	def _dnsname_match(dn, hostname):
	"""Matching according to RFC 6125, section 6.4.3
	- Hostnames are compared lower case.
	- For IDNA, both dn and hostname must be encoded as IDN A-label (ACE).
	- Partial wildcards like 'www*.example.org', multiple wildcards, sole
	wildcard or wildcards in labels other then the left-most label are not
	supported and a CertificateError is raised.
	- A wildcard must match at least one character.
	"""
	if not dn:
	return False
	wildcards = dn.count('*')
	# speed up common case w/o wildcards
	if not wildcards:
	return dn.lower() == hostname.lower()
	if wildcards > 1:
	raise CertificateError(
	"too many wildcards in certificate DNS name: {!r}.".format(dn))
	dn_leftmost, sep, dn_remainder = dn.partition('.')
	if '*' in dn_remainder:
	# Only match wildcard in leftmost segment.
	raise CertificateError(
	"wildcard can only be present in the leftmost label: "
	"{!r}.".format(dn))
	if not sep:
	# no right side
	raise CertificateError(
	"sole wildcard without additional labels are not support: "
	"{!r}.".format(dn))
	if dn_leftmost != '*':
	# no partial wildcard matching
	raise CertificateError(
	"partial wildcards in leftmost label are not supported: "
	"{!r}.".format(dn))
	hostname_leftmost, sep, hostname_remainder = hostname.partition('.')
	if not hostname_leftmost or not sep:
	# wildcard must match at least one char
	return False
	return dn_remainder.lower() == hostname_remainder.lower()
	def _inet_paton(ipname):
	"""Try to convert an IP address to packed binary form
	Supports IPv4 addresses on all platforms and IPv6 on platforms with IPv6
	support.
	"""
	# inet_aton() also accepts strings like '1', '127.1', some also trailing
	# data like '127.0.0.1 whatever'.
	try:
	addr = _socket.inet_aton(ipname)
	except OSError:
	# not an IPv4 address
	pass
	else:
	if _socket.inet_ntoa(addr) == ipname:
	# only accept injective ipnames
	return addr
	else:
	# refuse for short IPv4 notation and additional trailing data
	raise ValueError(
	"{!r} is not a quad-dotted IPv4 address.".format(ipname)
	)
	try:
	return _socket.inet_pton(_socket.AF_INET6, ipname)
	except OSError:
	raise ValueError("{!r} is neither an IPv4 nor an IP6 "
	"address.".format(ipname))
	except AttributeError:
	# AF_INET6 not available
	pass
	raise ValueError("{!r} is not an IPv4 address.".format(ipname))
	def _ipaddress_match(cert_ipaddress, host_ip):
	"""Exact matching of IP addresses.
	RFC 6125 explicitly doesn't define an algorithm for this
	(section 1.7.2 - "Out of Scope").
	"""
	# OpenSSL may add a trailing newline to a subjectAltName's IP address,
	# commonly woth IPv6 addresses. Strip off trailing \n.
	ip = _inet_paton(cert_ipaddress.rstrip())
	return ip == host_ip
	def match_hostname(cert, hostname):
	"""Verify that *cert* (in decoded format as returned by
	SSLSocket.getpeercert()) matches the *hostname*. RFC 2818 and RFC 6125
	rules are followed.
	The function matches IP addresses rather than dNSNames if hostname is a
	valid ipaddress string. IPv4 addresses are supported on all platforms.
	IPv6 addresses are supported on platforms with IPv6 support (AF_INET6
	and inet_pton).
	CertificateError is raised on failure. On success, the function
	returns nothing.
	"""
	if not cert:
	raise ValueError("empty or no certificate, match_hostname needs a "
	"SSL socket or SSL context with either "
	"CERT_OPTIONAL or CERT_REQUIRED")
	try:
	host_ip = _inet_paton(hostname)
	except ValueError:
	# Not an IP address (common case)
	host_ip = None
	dnsnames = []
	san = cert.get('subjectAltName', ())
	for key, value in san:
	if key == 'DNS':
	if host_ip is None and _dnsname_match(value, hostname):
	return
	dnsnames.append(value)
	elif key == 'IP Address':
	if host_ip is not None and _ipaddress_match(value, host_ip):
	return
	dnsnames.append(value)
	if not dnsnames:
	# The subject is only checked when there is no dNSName entry
	# in subjectAltName
	for sub in cert.get('subject', ()):
	for key, value in sub:
	# XXX according to RFC 2818, the most specific Common Name
	# must be used.
	if key == 'commonName':
	if _dnsname_match(value, hostname):
	return
	dnsnames.append(value)
	if len(dnsnames) > 1:
	raise CertificateError("hostname %r "
	"doesn't match either of %s"
	% (hostname, ', '.join(map(repr, dnsnames))))
	elif len(dnsnames) == 1:
	raise CertificateError("hostname %r "
	"doesn't match %r"
	% (hostname, dnsnames[0]))
	else:
	raise CertificateError("no appropriate commonName or "
	"subjectAltName fields were found")
	DefaultVerifyPaths = namedtuple("DefaultVerifyPaths",
	"cafile capath openssl_cafile_env openssl_cafile openssl_capath_env "
	"openssl_capath")
	def get_default_verify_paths():
	"""Return paths to default cafile and capath.
	"""
	parts = _ssl.get_default_verify_paths()
	# environment vars shadow paths
	cafile = os.environ.get(parts[0], parts[1])
	capath = os.environ.get(parts[2], parts[3])
	return DefaultVerifyPaths(cafile if os.path.isfile(cafile) else None,
	capath if os.path.isdir(capath) else None,
	*parts)
	class _ASN1Object(namedtuple("_ASN1Object", "nid shortname longname oid")):
	"""ASN.1 object identifier lookup
	"""
	__slots__ = ()
	def __new__(cls, oid):
	return super().__new__(cls, *_txt2obj(oid, name=False))
	@classmethod
	def fromnid(cls, nid):
	"""Create _ASN1Object from OpenSSL numeric ID
	"""
	return super().__new__(cls, *_nid2obj(nid))
	@classmethod
	def fromname(cls, name):
	"""Create _ASN1Object from short name, long name or OID
	"""
	return super().__new__(cls, *_txt2obj(name, name=True))
	class Purpose(_ASN1Object, _Enum):
	"""SSLContext purpose flags with X509v3 Extended Key Usage objects
	"""
	SERVER_AUTH = '1.3.6.1.5.5.7.3.1'
	CLIENT_AUTH = '1.3.6.1.5.5.7.3.2'
	class SSLContext(_SSLContext):
	"""An SSLContext holds various SSL-related configuration options and
	data, such as certificates and possibly a private key."""
	_windows_cert_stores = ("CA", "ROOT")
	sslsocket_class = None # SSLSocket is assigned later.
	sslobject_class = None # SSLObject is assigned later.
	def __new__(cls, protocol=PROTOCOL_TLS, *args, **kwargs):
	self = _SSLContext.__new__(cls, protocol)
	return self
	def _encode_hostname(self, hostname):
	if hostname is None:
	return None
	elif isinstance(hostname, str):
	return hostname.encode('idna').decode('ascii')
	else:
	return hostname.decode('ascii')
	def wrap_socket(self, sock, server_side=False,
	do_handshake_on_connect=True,
	suppress_ragged_eofs=True,
	server_hostname=None, session=None):
	# SSLSocket class handles server_hostname encoding before it calls
	# ctx._wrap_socket()
	return self.sslsocket_class._create(
	sock=sock,
	server_side=server_side,
	do_handshake_on_connect=do_handshake_on_connect,
	suppress_ragged_eofs=suppress_ragged_eofs,
	server_hostname=server_hostname,
	context=self,
	session=session
	)
	def wrap_bio(self, incoming, outgoing, server_side=False,
	server_hostname=None, session=None):
	# Need to encode server_hostname here because _wrap_bio() can only
	# handle ASCII str.
	return self.sslobject_class._create(
	incoming, outgoing, server_side=server_side,
	server_hostname=self._encode_hostname(server_hostname),
	session=session, context=self,
	)
	def set_npn_protocols(self, npn_protocols):
	protos = bytearray()
	for protocol in npn_protocols:
	b = bytes(protocol, 'ascii')
	if len(b) == 0 or len(b) > 255:
	raise SSLError('NPN protocols must be 1 to 255 in length')
	protos.append(len(b))
	protos.extend(b)
	self._set_npn_protocols(protos)
	def set_servername_callback(self, server_name_callback):
	if server_name_callback is None:
	self.sni_callback = None
	else:
	if not callable(server_name_callback):
	raise TypeError("not a callable object")
	def shim_cb(sslobj, servername, sslctx):
	servername = self._encode_hostname(servername)
	return server_name_callback(sslobj, servername, sslctx)
	self.sni_callback = shim_cb
	def set_alpn_protocols(self, alpn_protocols):
	protos = bytearray()
	for protocol in alpn_protocols:
	b = bytes(protocol, 'ascii')
	if len(b) == 0 or len(b) > 255:
	raise SSLError('ALPN protocols must be 1 to 255 in length')
	protos.append(len(b))
	protos.extend(b)
	self._set_alpn_protocols(protos)
	def _load_windows_store_certs(self, storename, purpose):
	certs = bytearray()
	try:
	for cert, encoding, trust in enum_certificates(storename):
	# CA certs are never PKCS#7 encoded
	if encoding == "x509_asn":
	if trust is True or purpose.oid in trust:
	certs.extend(cert)
	except PermissionError:
	warnings.warn("unable to enumerate Windows certificate store")
	if certs:
	self.load_verify_locations(cadata=certs)
	return certs
	def load_default_certs(self, purpose=Purpose.SERVER_AUTH):
	if not isinstance(purpose, _ASN1Object):
	raise TypeError(purpose)
	if sys.platform == "win32":
	for storename in self._windows_cert_stores:
	self._load_windows_store_certs(storename, purpose)
	self.set_default_verify_paths()
	if hasattr(_SSLContext, 'minimum_version'):
	@property
	def minimum_version(self):
	return TLSVersion(super().minimum_version)
	@minimum_version.setter
	def minimum_version(self, value):
	if value == TLSVersion.SSLv3:
	self.options &= ~Options.OP_NO_SSLv3
	super(SSLContext, SSLContext).minimum_version.__set__(self, value)
	@property
	def maximum_version(self):
	return TLSVersion(super().maximum_version)
	@maximum_version.setter
	def maximum_version(self, value):
	super(SSLContext, SSLContext).maximum_version.__set__(self, value)
	@property
	def options(self):
	return Options(super().options)
	@options.setter
	def options(self, value):
	super(SSLContext, SSLContext).options.__set__(self, value)
	if hasattr(_ssl, 'HOSTFLAG_NEVER_CHECK_SUBJECT'):
	@property
	def hostname_checks_common_name(self):
	ncs = self._host_flags & _ssl.HOSTFLAG_NEVER_CHECK_SUBJECT
	return ncs != _ssl.HOSTFLAG_NEVER_CHECK_SUBJECT
	@hostname_checks_common_name.setter
	def hostname_checks_common_name(self, value):
	if value:
	self._host_flags &= ~_ssl.HOSTFLAG_NEVER_CHECK_SUBJECT
	else:
	self._host_flags |= _ssl.HOSTFLAG_NEVER_CHECK_SUBJECT
	else:
	@property
	def hostname_checks_common_name(self):
	return True
	@property
	def protocol(self):
	return _SSLMethod(super().protocol)
	@property
	def verify_flags(self):
	return VerifyFlags(super().verify_flags)
	@verify_flags.setter
	def verify_flags(self, value):
	super(SSLContext, SSLContext).verify_flags.__set__(self, value)
	@property
	def verify_mode(self):
	value = super().verify_mode
	try:
	return VerifyMode(value)
	except ValueError:
	return value
	@verify_mode.setter
	def verify_mode(self, value):
	super(SSLContext, SSLContext).verify_mode.__set__(self, value)
	def create_default_context(purpose=Purpose.SERVER_AUTH, *, cafile=None,
	capath=None, cadata=None):
	"""Create a SSLContext object with default settings.
	NOTE: The protocol and settings may change anytime without prior
	deprecation. The values represent a fair balance between maximum
	compatibility and security.
	"""
	if not isinstance(purpose, _ASN1Object):
	raise TypeError(purpose)
	# SSLContext sets OP_NO_SSLv2, OP_NO_SSLv3, OP_NO_COMPRESSION,
	# OP_CIPHER_SERVER_PREFERENCE, OP_SINGLE_DH_USE and OP_SINGLE_ECDH_USE
	# by default.
	context = SSLContext(PROTOCOL_TLS)
	if purpose == Purpose.SERVER_AUTH:
	# verify certs and host name in client mode
	context.verify_mode = CERT_REQUIRED
	context.check_hostname = True
	if cafile or capath or cadata:
	context.load_verify_locations(cafile, capath, cadata)
	elif context.verify_mode != CERT_NONE:
	# no explicit cafile, capath or cadata but the verify mode is
	# CERT_OPTIONAL or CERT_REQUIRED. Let's try to load default system
	# root CA certificates for the given purpose. This may fail silently.
	context.load_default_certs(purpose)
	return context
	def _create_unverified_context(protocol=PROTOCOL_TLS, *, cert_reqs=CERT_NONE,
	check_hostname=False, purpose=Purpose.SERVER_AUTH,
	certfile=None, keyfile=None,
	cafile=None, capath=None, cadata=None):
	"""Create a SSLContext object for Python stdlib modules
	All Python stdlib modules shall use this function to create SSLContext
	objects in order to keep common settings in one place. The configuration
	is less restrict than create_default_context()'s to increase backward
	compatibility.
	"""
	if not isinstance(purpose, _ASN1Object):
	raise TypeError(purpose)
	# SSLContext sets OP_NO_SSLv2, OP_NO_SSLv3, OP_NO_COMPRESSION,
	# OP_CIPHER_SERVER_PREFERENCE, OP_SINGLE_DH_USE and OP_SINGLE_ECDH_USE
	# by default.
	context = SSLContext(protocol)
	if not check_hostname:
	context.check_hostname = False
	if cert_reqs is not None:
	context.verify_mode = cert_reqs
	if check_hostname:
	context.check_hostname = True
	if keyfile and not certfile:
	raise ValueError("certfile must be specified")
	if certfile or keyfile:
	context.load_cert_chain(certfile, keyfile)
	# load CA root certs
	if cafile or capath or cadata:
	context.load_verify_locations(cafile, capath, cadata)
	elif context.verify_mode != CERT_NONE:
	# no explicit cafile, capath or cadata but the verify mode is
	# CERT_OPTIONAL or CERT_REQUIRED. Let's try to load default system
	# root CA certificates for the given purpose. This may fail silently.
	context.load_default_certs(purpose)
	return context
	# Used by http.client if no context is explicitly passed.
	_create_default_https_context = create_default_context
	# Backwards compatibility alias, even though it's not a public name.
	_create_stdlib_context = _create_unverified_context
	class SSLObject:
	"""This class implements an interface on top of a low-level SSL object as
	implemented by OpenSSL. This object captures the state of an SSL connection
	but does not provide any network IO itself. IO needs to be performed
	through separate "BIO" objects which are OpenSSL's IO abstraction layer.
	This class does not have a public constructor. Instances are returned by
	``SSLContext.wrap_bio``. This class is typically used by framework authors
	that want to implement asynchronous IO for SSL through memory buffers.
	When compared to ``SSLSocket``, this object lacks the following features:
	* Any form of network IO, including methods such as ``recv`` and ``send``.
	* The ``do_handshake_on_connect`` and ``suppress_ragged_eofs`` machinery.
	"""
	def __init__(self, *args, **kwargs):
	raise TypeError(
	f"{self.__class__.__name__} does not have a public "
	f"constructor. Instances are returned by SSLContext.wrap_bio()."
	)
	@classmethod
	def _create(cls, incoming, outgoing, server_side=False,
	server_hostname=None, session=None, context=None):
	self = cls.__new__(cls)
	sslobj = context._wrap_bio(
	incoming, outgoing, server_side=server_side,
	server_hostname=server_hostname,
	owner=self, session=session
	)
	self._sslobj = sslobj
	return self
	@property
	def context(self):
	"""The SSLContext that is currently in use."""
	return self._sslobj.context
	@context.setter
	def context(self, ctx):
	self._sslobj.context = ctx
	@property
	def session(self):
	"""The SSLSession for client socket."""
	return self._sslobj.session
	@session.setter
	def session(self, session):
	self._sslobj.session = session
	@property
	def session_reused(self):
	"""Was the client session reused during handshake"""
	return self._sslobj.session_reused
	@property
	def server_side(self):
	"""Whether this is a server-side socket."""
	return self._sslobj.server_side
	@property
	def server_hostname(self):
	"""The currently set server hostname (for SNI), or ``None`` if no
	server hostame is set."""
	return self._sslobj.server_hostname
	def read(self, len=1024, buffer=None):
	"""Read up to 'len' bytes from the SSL object and return them.
	If 'buffer' is provided, read into this buffer and return the number of
	bytes read.
	"""
	if buffer is not None:
	v = self._sslobj.read(len, buffer)
	else:
	v = self._sslobj.read(len)
	return v
	def write(self, data):
	"""Write 'data' to the SSL object and return the number of bytes
	written.
	The 'data' argument must support the buffer interface.
	"""
	return self._sslobj.write(data)
	def getpeercert(self, binary_form=False):
	"""Returns a formatted version of the data in the certificate provided
	by the other end of the SSL channel.
	Return None if no certificate was provided, {} if a certificate was
	provided, but not validated.
	"""
	return self._sslobj.getpeercert(binary_form)
	def selected_npn_protocol(self):
	"""Return the currently selected NPN protocol as a string, or ``None``
	if a next protocol was not negotiated or if NPN is not supported by one
	of the peers."""
	if _ssl.HAS_NPN:
	return self._sslobj.selected_npn_protocol()
	def selected_alpn_protocol(self):
	"""Return the currently selected ALPN protocol as a string, or ``None``
	if a next protocol was not negotiated or if ALPN is not supported by one
	of the peers."""
	if _ssl.HAS_ALPN:
	return self._sslobj.selected_alpn_protocol()
	def cipher(self):
	"""Return the currently selected cipher as a 3-tuple ``(name,
	ssl_version, secret_bits)``."""
	return self._sslobj.cipher()
	def shared_ciphers(self):
	"""Return a list of ciphers shared by the client during the handshake or
	None if this is not a valid server connection.
	"""
	return self._sslobj.shared_ciphers()
	def compression(self):
	"""Return the current compression algorithm in use, or ``None`` if
	compression was not negotiated or not supported by one of the peers."""
	return self._sslobj.compression()
	def pending(self):
	"""Return the number of bytes that can be read immediately."""
	return self._sslobj.pending()
	def do_handshake(self):
	"""Start the SSL/TLS handshake."""
	self._sslobj.do_handshake()
	def unwrap(self):
	"""Start the SSL shutdown handshake."""
	return self._sslobj.shutdown()
	def get_channel_binding(self, cb_type="tls-unique"):
	"""Get channel binding data for current connection. Raise ValueError
	if the requested `cb_type` is not supported. Return bytes of the data
	or None if the data is not available (e.g. before the handshake)."""
	return self._sslobj.get_channel_binding(cb_type)
	def version(self):
	"""Return a string identifying the protocol version used by the
	current SSL channel. """
	return self._sslobj.version()
	def verify_client_post_handshake(self):
	return self._sslobj.verify_client_post_handshake()
	def _sslcopydoc(func):
	"""Copy docstring from SSLObject to SSLSocket"""
	func.__doc__ = getattr(SSLObject, func.__name__).__doc__
	return func
	class SSLSocket(socket):
	"""This class implements a subtype of socket.socket that wraps
	the underlying OS socket in an SSL context when necessary, and
	provides read and write methods over that channel. """
	def __init__(self, *args, **kwargs):
	raise TypeError(
	f"{self.__class__.__name__} does not have a public "
	f"constructor. Instances are returned by "
	f"SSLContext.wrap_socket()."
	)
	@classmethod
	def _create(cls, sock, server_side=False, do_handshake_on_connect=True,
	suppress_ragged_eofs=True, server_hostname=None,
	context=None, session=None):
	if sock.getsockopt(SOL_SOCKET, SO_TYPE) != SOCK_STREAM:
	raise NotImplementedError("only stream sockets are supported")
	if server_side:
	if server_hostname:
	raise ValueError("server_hostname can only be specified "
	"in client mode")
	if session is not None:
	raise ValueError("session can only be specified in "
	"client mode")
	if context.check_hostname and not server_hostname:
	raise ValueError("check_hostname requires server_hostname")
	kwargs = dict(
	family=sock.family, type=sock.type, proto=sock.proto,
	fileno=sock.fileno()
	)
	self = cls.__new__(cls, **kwargs)
	super(SSLSocket, self).__init__(**kwargs)
	self.settimeout(sock.gettimeout())
	sock.detach()
	self._context = context
	self._session = session
	self._closed = False
	self._sslobj = None
	self.server_side = server_side
	self.server_hostname = context._encode_hostname(server_hostname)
	self.do_handshake_on_connect = do_handshake_on_connect
	self.suppress_ragged_eofs = suppress_ragged_eofs
	# See if we are connected
	try:
	self.getpeername()
	except OSError as e:
	if e.errno != errno.ENOTCONN:
	raise
	connected = False
	else:
	connected = True
	self._connected = connected
	if connected:
	# create the SSL object
	try:
	self._sslobj = self._context._wrap_socket(
	self, server_side, self.server_hostname,
	owner=self, session=self._session,
	)
	if do_handshake_on_connect:
	timeout = self.gettimeout()
	if timeout == 0.0:
	# non-blocking
	raise ValueError("do_handshake_on_connect should not be specified for non-blocking sockets")
	self.do_handshake()
	except (OSError, ValueError):
	self.close()
	raise
	return self
	@property
	@_sslcopydoc
	def context(self):
	return self._context
	@context.setter
	def context(self, ctx):
	self._context = ctx
	self._sslobj.context = ctx
	@property
	@_sslcopydoc
	def session(self):
	if self._sslobj is not None:
	return self._sslobj.session
	@session.setter
	def session(self, session):
	self._session = session
	if self._sslobj is not None:
	self._sslobj.session = session
	@property
	@_sslcopydoc
	def session_reused(self):
	if self._sslobj is not None:
	return self._sslobj.session_reused
	def dup(self):
	raise NotImplementedError("Can't dup() %s instances" %
	self.__class__.__name__)
	def _checkClosed(self, msg=None):
	# raise an exception here if you wish to check for spurious closes
	pass
	def _check_connected(self):
	if not self._connected:
	# getpeername() will raise ENOTCONN if the socket is really
	# not connected; note that we can be connected even without
	# _connected being set, e.g. if connect() first returned
	# EAGAIN.
	self.getpeername()
	def read(self, len=1024, buffer=None):
	"""Read up to LEN bytes and return them.
	Return zero-length string on EOF."""
	self._checkClosed()
	if self._sslobj is None:
	raise ValueError("Read on closed or unwrapped SSL socket.")
	try:
	if buffer is not None:
	return self._sslobj.read(len, buffer)
	else:
	return self._sslobj.read(len)
	except SSLError as x:
	if x.args[0] == SSL_ERROR_EOF and self.suppress_ragged_eofs:
	if buffer is not None:
	return 0
	else:
	return b''
	else:
	raise
	def write(self, data):
	"""Write DATA to the underlying SSL channel. Returns
	number of bytes of DATA actually transmitted."""
	self._checkClosed()
	if self._sslobj is None:
	raise ValueError("Write on closed or unwrapped SSL socket.")
	return self._sslobj.write(data)
	@_sslcopydoc
	def getpeercert(self, binary_form=False):
	self._checkClosed()
	self._check_connected()
	return self._sslobj.getpeercert(binary_form)
	@_sslcopydoc
	def selected_npn_protocol(self):
	self._checkClosed()
	if self._sslobj is None or not _ssl.HAS_NPN:
	return None
	else:
	return self._sslobj.selected_npn_protocol()
	@_sslcopydoc
	def selected_alpn_protocol(self):
	self._checkClosed()
	if self._sslobj is None or not _ssl.HAS_ALPN:
	return None
	else:
	return self._sslobj.selected_alpn_protocol()
	@_sslcopydoc
	def cipher(self):
	self._checkClosed()
	if self._sslobj is None:
	return None
	else:
	return self._sslobj.cipher()
	@_sslcopydoc
	def shared_ciphers(self):
	self._checkClosed()
	if self._sslobj is None:
	return None
	else:
	return self._sslobj.shared_ciphers()
	@_sslcopydoc
	def compression(self):
	self._checkClosed()
	if self._sslobj is None:
	return None
	else:
	return self._sslobj.compression()
	def send(self, data, flags=0):
	self._checkClosed()
	if self._sslobj is not None:
	if flags != 0:
	raise ValueError(
	"non-zero flags not allowed in calls to send() on %s" %
	self.__class__)
	return self._sslobj.write(data)
	else:
	return super().send(data, flags)
	def sendto(self, data, flags_or_addr, addr=None):
	self._checkClosed()
	if self._sslobj is not None:
	raise ValueError("sendto not allowed on instances of %s" %
	self.__class__)
	elif addr is None:
	return super().sendto(data, flags_or_addr)
	else:
	return super().sendto(data, flags_or_addr, addr)
	def sendmsg(self, *args, **kwargs):
	# Ensure programs don't send data unencrypted if they try to
	# use this method.
	raise NotImplementedError("sendmsg not allowed on instances of %s" %
	self.__class__)
	def sendall(self, data, flags=0):
	self._checkClosed()
	if self._sslobj is not None:
	if flags != 0:
	raise ValueError(
	"non-zero flags not allowed in calls to sendall() on %s" %
	self.__class__)
	count = 0
	with memoryview(data) as view, view.cast("B") as byte_view:
	amount = len(byte_view)
	while count < amount:
	v = self.send(byte_view[count:])
	count += v
	else:
	return super().sendall(data, flags)
	def sendfile(self, file, offset=0, count=None):
	"""Send a file, possibly by using os.sendfile() if this is a
	clear-text socket. Return the total number of bytes sent.
	"""
	if self._sslobj is not None:
	return self._sendfile_use_send(file, offset, count)
	else:
	# os.sendfile() works with plain sockets only
	return super().sendfile(file, offset, count)
	def recv(self, buflen=1024, flags=0):
	self._checkClosed()
	if self._sslobj is not None:
	if flags != 0:
	raise ValueError(
	"non-zero flags not allowed in calls to recv() on %s" %
	self.__class__)
	return self.read(buflen)
	else:
	return super().recv(buflen, flags)
	def recv_into(self, buffer, nbytes=None, flags=0):
	self._checkClosed()
	if buffer and (nbytes is None):
	nbytes = len(buffer)
	elif nbytes is None:
	nbytes = 1024
	if self._sslobj is not None:
	if flags != 0:
	raise ValueError(
	"non-zero flags not allowed in calls to recv_into() on %s" %
	self.__class__)
	return self.read(nbytes, buffer)
	else:
	return super().recv_into(buffer, nbytes, flags)
	def recvfrom(self, buflen=1024, flags=0):
	self._checkClosed()
	if self._sslobj is not None:
	raise ValueError("recvfrom not allowed on instances of %s" %
	self.__class__)
	else:
	return super().recvfrom(buflen, flags)
	def recvfrom_into(self, buffer, nbytes=None, flags=0):
	self._checkClosed()
	if self._sslobj is not None:
	raise ValueError("recvfrom_into not allowed on instances of %s" %
	self.__class__)
	else:
	return super().recvfrom_into(buffer, nbytes, flags)
	def recvmsg(self, *args, **kwargs):
	raise NotImplementedError("recvmsg not allowed on instances of %s" %
	self.__class__)
	def recvmsg_into(self, *args, **kwargs):
	raise NotImplementedError("recvmsg_into not allowed on instances of "
	"%s" % self.__class__)
	@_sslcopydoc
	def pending(self):
	self._checkClosed()
	if self._sslobj is not None:
	return self._sslobj.pending()
	else:
	return 0
	def shutdown(self, how):
	self._checkClosed()
	self._sslobj = None
	super().shutdown(how)
	@_sslcopydoc
	def unwrap(self):
	if self._sslobj:
	s = self._sslobj.shutdown()
	self._sslobj = None
	return s
	else:
	raise ValueError("No SSL wrapper around " + str(self))
	@_sslcopydoc
	def verify_client_post_handshake(self):
	if self._sslobj:
	return self._sslobj.verify_client_post_handshake()
	else:
	raise ValueError("No SSL wrapper around " + str(self))
	def _real_close(self):
	self._sslobj = None
	super()._real_close()
	@_sslcopydoc
	def do_handshake(self, block=False):
	self._check_connected()
	timeout = self.gettimeout()
	try:
	if timeout == 0.0 and block:
	self.settimeout(None)
	self._sslobj.do_handshake()
	finally:
	self.settimeout(timeout)
	def _real_connect(self, addr, connect_ex):
	if self.server_side:
	raise ValueError("can't connect in server-side mode")
	# Here we assume that the socket is client-side, and not
	# connected at the time of the call. We connect it, then wrap it.
	if self._connected or self._sslobj is not None:
	raise ValueError("attempt to connect already-connected SSLSocket!")
	self._sslobj = self.context._wrap_socket(
	self, False, self.server_hostname,
	owner=self, session=self._session
	)
	try:
	if connect_ex:
	rc = super().connect_ex(addr)
	else:
	rc = None
	super().connect(addr)
	if not rc:
	self._connected = True
	if self.do_handshake_on_connect:
	self.do_handshake()
	return rc
	except (OSError, ValueError):
	self._sslobj = None
	raise
	def connect(self, addr):
	"""Connects to remote ADDR, and then wraps the connection in
	an SSL channel."""
	self._real_connect(addr, False)
	def connect_ex(self, addr):
	"""Connects to remote ADDR, and then wraps the connection in
	an SSL channel."""
	return self._real_connect(addr, True)
	def accept(self):
	"""Accepts a new connection from a remote client, and returns
	a tuple containing that new connection wrapped with a server-side
	SSL channel, and the address of the remote client."""
	newsock, addr = super().accept()
	newsock = self.context.wrap_socket(newsock,
	do_handshake_on_connect=self.do_handshake_on_connect,
	suppress_ragged_eofs=self.suppress_ragged_eofs,
	server_side=True)
	return newsock, addr
	@_sslcopydoc
	def get_channel_binding(self, cb_type="tls-unique"):
	if self._sslobj is not None:
	return self._sslobj.get_channel_binding(cb_type)
	else:
	if cb_type not in CHANNEL_BINDING_TYPES:
	raise ValueError(
	"{0} channel binding type not implemented".format(cb_type)
	)
	return None
	@_sslcopydoc
	def version(self):
	if self._sslobj is not None:
	return self._sslobj.version()
	else:
	return None
	# Python does not support forward declaration of types.
	SSLContext.sslsocket_class = SSLSocket
	SSLContext.sslobject_class = SSLObject
	def wrap_socket(sock, keyfile=None, certfile=None,
	server_side=False, cert_reqs=CERT_NONE,
	ssl_version=PROTOCOL_TLS, ca_certs=None,
	do_handshake_on_connect=True,
	suppress_ragged_eofs=True,
	ciphers=None):
	if server_side and not certfile:
	raise ValueError("certfile must be specified for server-side "
	"operations")
	if keyfile and not certfile:
	raise ValueError("certfile must be specified")
	context = SSLContext(ssl_version)
	context.verify_mode = cert_reqs
	if ca_certs:
	context.load_verify_locations(ca_certs)
	if certfile:
	context.load_cert_chain(certfile, keyfile)
	if ciphers:
	context.set_ciphers(ciphers)
	return context.wrap_socket(
	sock=sock, server_side=server_side,
	do_handshake_on_connect=do_handshake_on_connect,
	suppress_ragged_eofs=suppress_ragged_eofs
	)
	# some utility functions
	def cert_time_to_seconds(cert_time):
	"""Return the time in seconds since the Epoch, given the timestring
	representing the "notBefore" or "notAfter" date from a certificate
	in ``"%b %d %H:%M:%S %Y %Z"`` strptime format (C locale).
	"notBefore" or "notAfter" dates must use UTC (RFC 5280).
	Month is one of: Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
	UTC should be specified as GMT (see ASN1_TIME_print())
	"""
	from time import strptime
	from calendar import timegm
	months = (
	"Jan","Feb","Mar","Apr","May","Jun",
	"Jul","Aug","Sep","Oct","Nov","Dec"
	)
	time_format = ' %d %H:%M:%S %Y GMT' # NOTE: no month, fixed GMT
	try:
	month_number = months.index(cert_time[:3].title()) + 1
	except ValueError:
	raise ValueError('time data %r does not match '
	'format "%%b%s"' % (cert_time, time_format))
	else:
	# found valid month
	tt = strptime(cert_time[3:], time_format)
	# return an integer, the previous mktime()-based implementation
	# returned a float (fractional seconds are always zero here).
	return timegm((tt[0], month_number) + tt[2:6])
	PEM_HEADER = "-----BEGIN CERTIFICATE-----"
	PEM_FOOTER = "-----END CERTIFICATE-----"
	def DER_cert_to_PEM_cert(der_cert_bytes):
	"""Takes a certificate in binary DER format and returns the
	PEM version of it as a string."""
	f = str(base64.standard_b64encode(der_cert_bytes), 'ASCII', 'strict')
	ss = [PEM_HEADER]
	ss += [f[i:i+64] for i in range(0, len(f), 64)]
	ss.append(PEM_FOOTER + '\n')
	return '\n'.join(ss)
	def PEM_cert_to_DER_cert(pem_cert_string):
	"""Takes a certificate in ASCII PEM format and returns the
	DER-encoded version of it as a byte sequence"""
	if not pem_cert_string.startswith(PEM_HEADER):
	raise ValueError("Invalid PEM encoding; must start with %s"
	% PEM_HEADER)
	if not pem_cert_string.strip().endswith(PEM_FOOTER):
	raise ValueError("Invalid PEM encoding; must end with %s"
	% PEM_FOOTER)
	d = pem_cert_string.strip()[len(PEM_HEADER):-len(PEM_FOOTER)]
	return base64.decodebytes(d.encode('ASCII', 'strict'))
	def get_server_certificate(addr, ssl_version=PROTOCOL_TLS, ca_certs=None):
	"""Retrieve the certificate from the server at the specified address,
	and return it as a PEM-encoded string.
	If 'ca_certs' is specified, validate the server cert against it.
	If 'ssl_version' is specified, use it in the connection attempt."""
	host, port = addr
	if ca_certs is not None:
	cert_reqs = CERT_REQUIRED
	else:
	cert_reqs = CERT_NONE
	context = _create_stdlib_context(ssl_version,
	cert_reqs=cert_reqs,
	cafile=ca_certs)
	with create_connection(addr) as sock:
	with context.wrap_socket(sock) as sslsock:
	dercert = sslsock.getpeercert(True)
	return DER_cert_to_PEM_cert(dercert)
	def get_protocol_name(protocol_code):
	return _PROTOCOL_NAMES.get(protocol_code, '<unknown>')