Client.open_secure_channel() - Code Metrics - Inspection of "new attempt at disabling broken test" - FreeOpcUa/python-opcua - Measure and Improve Code Quality continuously with Scrutinizer

Completed

Push — master ( 41c04b...6083f5 )

by Olivier

created 2016-11-13 10:21 UTC

Client.open_secure_channel() A

↳ Parent: Project

Complexity

Conditions

Size

Total Lines

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	12
CRAP Score	2.0017

Importance

Changes

Metric	Value
cc	2
c	0
b	0
f	0
dl	0
loc	16
ccs	12
cts	13
cp	0.9231
crap	2.0017
rs	9.4285

from __future__ import division  # support for python2
from threading import Thread, Condition
import logging
try:
    from urllib.parse import urlparse
except ImportError:  # support for python2
    from urlparse import urlparse

from opcua import ua
from opcua.client.ua_client import UaClient
from opcua.common.node import Node
from opcua.common.manage_nodes import delete_nodes
from opcua.common.subscription import Subscription
from opcua.common import utils
from opcua.crypto import security_policies
from opcua.common.shortcuts import Shortcuts
use_crypto = True
try:
    from opcua.crypto import uacrypto
except ImportError:
    print("cryptography is not installed, use of crypto disabled")
    use_crypto = False


class KeepAlive(Thread):

    """
    Used by Client to keep the session open.
    OPCUA defines timeout both for sessions and secure channel
    """

    def __init__(self, client, timeout):
        """
        :param session_timeout: Timeout to re-new the session
            in milliseconds.
        """
        Thread.__init__(self)
        self.logger = logging.getLogger(__name__)

        self.client = client
        self._dostop = False
        self._cond = Condition()
        self.timeout = timeout

        # some server support no timeout, but we do not trust them
        if self.timeout == 0:
            self.timeout = 3600000 # 1 hour

    def run(self):
        self.logger.debug("starting keepalive thread with period of %s milliseconds", self.timeout)
        server_state = self.client.get_node(ua.FourByteNodeId(ua.ObjectIds.Server_ServerStatus_State))
        while not self._dostop:
            with self._cond:
                self._cond.wait(self.timeout / 1000)
            if self._dostop:
                break
            self.logger.debug("renewing channel")
            self.client.open_secure_channel(renew=True)
            val = server_state.get_value()
            self.logger.debug("server state is: %s ", val)
        self.logger.debug("keepalive thread has stopped")

    def stop(self):
        self.logger.debug("stoping keepalive thread")
        self._dostop = True
        with self._cond:
            self._cond.notify_all()


class Client(object):

    """
    High level client to connect to an OPC-UA server.

    This class makes it easy to connect and browse address space.
    It attemps to expose as much functionality as possible
    but if you want more flexibility it is possible and adviced to
    use UaClient object, available as self.uaclient
    which offers the raw OPC-UA services interface.
    """

    def __init__(self, url, timeout=4):
        """

        :param url: url of the server.
            if you are unsure of url, write at least hostname
            and port and call get_endpoints

        :param timeout:
            Each request sent to the server expects an answer within this
            time. The timeout is specified in seconds.
        """
        self.logger = logging.getLogger(__name__)
        self.server_url = urlparse(url)
        self.name = "Pure Python Client"
        self.description = self.name
        self.application_uri = "urn:freeopcua:client"
        self.product_uri = "urn:freeopcua.github.no:client"
        self.security_policy = ua.SecurityPolicy()
        self.secure_channel_id = None
        self.secure_channel_timeout = 3600000 # 1 hour
        self.session_timeout = 3600000 # 1 hour
        self._policy_ids = []
        self.uaclient = UaClient(timeout)
        self.user_certificate = None
        self.user_private_key = None
        self._session_counter = 1
        self.keepalive = None
        self.nodes = Shortcuts(self.uaclient)

    def __enter__(self):
        self.connect()
        return self

    def __exit__(self, exc_type, exc_value, traceback):
        self.disconnect()

    @staticmethod
    def find_endpoint(endpoints, security_mode, policy_uri):
        """
        Find endpoint with required security mode and policy URI
        """
        for ep in endpoints:
            if (ep.EndpointUrl.startswith(ua.OPC_TCP_SCHEME) and
                    ep.SecurityMode == security_mode and
                    ep.SecurityPolicyUri == policy_uri):
                return ep
        raise ua.UaError("No matching endpoints: {}, {}".format(
                         security_mode, policy_uri))

    def set_security_string(self, string):
        """
        Set SecureConnection mode. String format:
        Policy,Mode,certificate,private_key[,server_private_key]
        where Policy is Basic128Rsa15 or Basic256,
            Mode is Sign or SignAndEncrypt
            certificate, private_key and server_private_key are
                paths to .pem or .der files
        Call this before connect()
        """
        if not string:
            return
        parts = string.split(',')
        if len(parts) < 4:
            raise ua.UaError('Wrong format: `{}`, expected at least 4 comma-separated values'.format(string))
        policy_class = getattr(security_policies, 'SecurityPolicy' + parts[0])
        mode = getattr(ua.MessageSecurityMode, parts[1])
        return self.set_security(policy_class, parts[2], parts[3],
                                 parts[4] if len(parts) >= 5 else None, mode)

    def set_security(self, policy, certificate_path, private_key_path,
                     server_certificate_path=None,
                     mode=ua.MessageSecurityMode.SignAndEncrypt):
        """
        Set SecureConnection mode.
        Call this before connect()
        """
        if server_certificate_path is None:
            # load certificate from server's list of endpoints
            endpoints = self.connect_and_get_server_endpoints()
            endpoint = Client.find_endpoint(endpoints, mode, policy.URI)
            server_cert = uacrypto.x509_from_der(endpoint.ServerCertificate)
        else:
            server_cert = uacrypto.load_certificate(server_certificate_path)
        cert = uacrypto.load_certificate(certificate_path)
        pk = uacrypto.load_private_key(private_key_path)
        self.security_policy = policy(server_cert, cert, pk, mode)
        self.uaclient.set_security(self.security_policy)

    def load_client_certificate(self, path):
        """
        load our certificate from file, either pem or der
        """
        self.user_certificate = uacrypto.load_certificate(path)

    def load_private_key(self, path):
        """
        Load user private key. This is used for authenticating using certificate
        """
        self.user_private_key = uacrypto.load_private_key(path)

    def connect_and_get_server_endpoints(self):
        """
        Connect, ask server for endpoints, and disconnect
        """
        self.connect_socket()
        self.send_hello()
        self.open_secure_channel()
        endpoints = self.get_endpoints()
        self.close_secure_channel()
        self.disconnect_socket()
        return endpoints

    def connect_and_find_servers(self):
        """
        Connect, ask server for a list of known servers, and disconnect
        """
        self.connect_socket()
        self.send_hello()
        self.open_secure_channel()  # spec says it should not be necessary to open channel
        servers = self.find_servers()
        self.close_secure_channel()
        self.disconnect_socket()
        return servers

    def connect_and_find_servers_on_network(self):
        """
        Connect, ask server for a list of known servers on network, and disconnect
        """
        self.connect_socket()
        self.send_hello()
        self.open_secure_channel()
        servers = self.find_servers_on_network()
        self.close_secure_channel()
        self.disconnect_socket()
        return servers

    def connect(self):
        """
        High level method
        Connect, create and activate session
        """
        self.connect_socket()
        self.send_hello()
        self.open_secure_channel()
        self.create_session()
        self.activate_session(username=self.server_url.username, password=self.server_url.password, certificate=self.user_certificate)

    def disconnect(self):
        """
        High level method
        Close session, secure channel and socket
        """
        self.close_session()
        self.close_secure_channel()
        self.disconnect_socket()

    def connect_socket(self):
        """
        connect to socket defined in url
        """
        self.uaclient.connect_socket(self.server_url.hostname, self.server_url.port)

    def disconnect_socket(self):
        self.uaclient.disconnect_socket()

    def send_hello(self):
        """
        Send OPC-UA hello to server
        """
        ack = self.uaclient.send_hello(self.server_url.geturl())
        # FIXME check ack

    def open_secure_channel(self, renew=False):
        """
        Open secure channel, if renew is True, renew channel
        """
        params = ua.OpenSecureChannelParameters()
        params.ClientProtocolVersion = 0
        params.RequestType = ua.SecurityTokenRequestType.Issue
        if renew:
            params.RequestType = ua.SecurityTokenRequestType.Renew
        params.SecurityMode = self.security_policy.Mode
        params.RequestedLifetime = self.secure_channel_timeout
        nonce = utils.create_nonce(self.security_policy.symmetric_key_size)   # length should be equal to the length of key of symmetric encryption
        params.ClientNonce = nonce	# this nonce is used to create a symmetric key
        result = self.uaclient.open_secure_channel(params)
        self.security_policy.make_symmetric_key(nonce, result.ServerNonce)
        self.secure_channel_timeout = result.SecurityToken.RevisedLifetime

    def close_secure_channel(self):
        return self.uaclient.close_secure_channel()

    def get_endpoints(self):
        params = ua.GetEndpointsParameters()
        params.EndpointUrl = self.server_url.geturl()
        return self.uaclient.get_endpoints(params)

    def register_server(self, server, discovery_configuration=None):
        """
        register a server to discovery server
        if discovery_configuration is provided, the newer register_server2 service call is used
        """
        serv = ua.RegisteredServer()
        serv.ServerUri = server.application_uri
        serv.ProductUri = server.product_uri
        serv.DiscoveryUrls = [server.endpoint.geturl()]
        serv.ServerType = server.application_type
        serv.ServerNames = [ua.LocalizedText(server.name)]
        serv.IsOnline = True
        if discovery_configuration:
            params = ua.RegisterServer2Parameters()
            params.Server = serv
            params.DiscoveryConfiguration = discovery_configuration
            return self.uaclient.register_server2(params)
        else:
            return self.uaclient.register_server(serv)

    def find_servers(self, uris=None):
        """
        send a FindServer request to the server. The answer should be a list of
        servers the server knows about
        A list of uris can be provided, only server having matching uris will be returned
        """
        if uris is None:
            uris = []
        params = ua.FindServersParameters()
        params.EndpointUrl = self.server_url.geturl()
        params.ServerUris = uris
        return self.uaclient.find_servers(params)

    def find_servers_on_network(self):
        params = ua.FindServersOnNetworkParameters()
        return self.uaclient.find_servers_on_network(params)

    def create_session(self):
        """
        send a CreateSessionRequest to server with reasonable parameters.
        If you want o modify settings look at code of this methods
        and make your own
        """
        desc = ua.ApplicationDescription()
        desc.ApplicationUri = self.application_uri
        desc.ProductUri = self.product_uri
        desc.ApplicationName = ua.LocalizedText(self.name)
        desc.ApplicationType = ua.ApplicationType.Client

        params = ua.CreateSessionParameters()
        nonce = utils.create_nonce(32)  # at least 32 random bytes for server to prove possession of private key (specs part 4, 5.6.2.2)
        params.ClientNonce = nonce
        params.ClientCertificate = self.security_policy.client_certificate
        params.ClientDescription = desc
        params.EndpointUrl = self.server_url.geturl()
        params.SessionName = self.description + " Session" + str(self._session_counter)
        params.RequestedSessionTimeout = 3600000
        params.MaxResponseMessageSize = 0  # means no max size
        response = self.uaclient.create_session(params)
        if self.security_policy.client_certificate is None:
            data = nonce
        else:
            data = self.security_policy.client_certificate + nonce
        self.security_policy.asymmetric_cryptography.verify(data, response.ServerSignature.Signature)
        self._server_nonce = response.ServerNonce
        if not self.security_policy.server_certificate:
            self.security_policy.server_certificate = response.ServerCertificate
        elif self.security_policy.server_certificate != response.ServerCertificate:
            raise ua.UaError("Server certificate mismatch")
        # remember PolicyId's: we will use them in activate_session()
        ep = Client.find_endpoint(response.ServerEndpoints, self.security_policy.Mode, self.security_policy.URI)
        self._policy_ids = ep.UserIdentityTokens
        self.session_timeout = response.RevisedSessionTimeout
        self.keepalive = KeepAlive(self, min(self.session_timeout, self.secure_channel_timeout) * 0.7)  # 0.7 is from spec
        self.keepalive.start()
        return response

    def server_policy_id(self, token_type, default):
        """
        Find PolicyId of server's UserTokenPolicy by token_type.
        Return default if there's no matching UserTokenPolicy.
        """
        for policy in self._policy_ids:
            if policy.TokenType == token_type:
                return policy.PolicyId
        return default

    def server_policy_uri(self, token_type):
        """
        Find SecurityPolicyUri of server's UserTokenPolicy by token_type.
        If SecurityPolicyUri is empty, use default SecurityPolicyUri
        of the endpoint
        """
        for policy in self._policy_ids:
            if policy.TokenType == token_type:
                if policy.SecurityPolicyUri:
                    return policy.SecurityPolicyUri
                else:   # empty URI means "use this endpoint's policy URI"
                    return self.security_policy.URI
        return self.security_policy.URI

    def activate_session(self, username=None, password=None, certificate=None):
        """
        Activate session using either username and password or private_key
        """
        params = ua.ActivateSessionParameters()
        challenge = b""
        if self.security_policy.server_certificate is not None:
            challenge += self.security_policy.server_certificate
        if self._server_nonce is not None:
            challenge += self._server_nonce
        params.ClientSignature.Algorithm = b"http://www.w3.org/2000/09/xmldsig#rsa-sha1"
        params.ClientSignature.Signature = self.security_policy.asymmetric_cryptography.signature(challenge)
        params.LocaleIds.append("en")
        if not username and not certificate:
            self._add_anonymous_auth(params)
        elif certificate:
            self._add_certificate_auth(params, certificate, challenge)
        else:
            self._add_user_auth(params, username, password)
        return self.uaclient.activate_session(params)

    def _add_anonymous_auth(self, params):
        params.UserIdentityToken = ua.AnonymousIdentityToken()
        params.UserIdentityToken.PolicyId = self.server_policy_id(ua.UserTokenType.Anonymous, b"anonymous")

    def _add_certificate_auth(self, params, certificate, challenge):
        params.UserIdentityToken = ua.X509IdentityToken()
        params.UserIdentityToken.PolicyId = self.server_policy_id(ua.UserTokenType.Certificate, b"certificate_basic256")
        params.UserIdentityToken.CertificateData = uacrypto.der_from_x509(certificate)
        # specs part 4, 5.6.3.1: the data to sign is created by appending
        # the last serverNonce to the serverCertificate
        sig = uacrypto.sign_sha1(self.user_private_key, challenge)
        params.UserTokenSignature = ua.SignatureData()
        params.UserTokenSignature.Algorithm = b"http://www.w3.org/2000/09/xmldsig#rsa-sha1"
        params.UserTokenSignature.Signature = sig

    def _add_user_auth(self, params, username, password):
        params.UserIdentityToken = ua.UserNameIdentityToken()
        params.UserIdentityToken.UserName = username
        policy_uri = self.server_policy_uri(ua.UserTokenType.UserName)
        if not policy_uri or policy_uri == security_policies.POLICY_NONE_URI:
            # see specs part 4, 7.36.3: if the token is NOT encrypted,
            # then the password only contains UTF-8 encoded password
            # and EncryptionAlgorithm is null
            if self.server_url.password:
                self.logger.warning("Sending plain-text password")
                params.UserIdentityToken.Password = password
            params.UserIdentityToken.EncryptionAlgorithm = ''
        elif self.server_url.password:
            data, uri = self._encrypt_password(password, policy_uri)
            params.UserIdentityToken.Password = data 
            params.UserIdentityToken.EncryptionAlgorithm = uri
        params.UserIdentityToken.PolicyId = self.server_policy_id(ua.UserTokenType.UserName, b"username_basic256")

    def _encrypt_password(self, password, policy_uri):
        pubkey = uacrypto.x509_from_der(self.security_policy.server_certificate).public_key()
        # see specs part 4, 7.36.3: if the token is encrypted, password
        # shall be converted to UTF-8 and serialized with server nonce
        passwd = password.encode("utf8")
        if self._server_nonce is not None:
            passwd += self._server_nonce
        etoken = ua.ua_binary.Primitives.Bytes.pack(passwd)
        data, uri = security_policies.encrypt_asymmetric(pubkey, etoken, policy_uri)
        return data, uri

    def close_session(self):
        """
        Close session
        """
        if self.keepalive:
            self.keepalive.stop()
        return self.uaclient.close_session(True)

    def get_root_node(self):
        return self.get_node(ua.TwoByteNodeId(ua.ObjectIds.RootFolder))

    def get_objects_node(self):
        return self.get_node(ua.TwoByteNodeId(ua.ObjectIds.ObjectsFolder))

    def get_server_node(self):
        return self.get_node(ua.FourByteNodeId(ua.ObjectIds.Server))

    def get_node(self, nodeid):
        """
        Get node using NodeId object or a string representing a NodeId
        """
        return Node(self.uaclient, nodeid)

    def create_subscription(self, period, handler):
        """
        Create a subscription.
        returns a Subscription object which allow
        to subscribe to events or data on server
        handler argument is a class with data_change and/or event methods.
        These methods will be called when notfication from server are received.
        See example-client.py.
        Do not do expensive/slow or network operation from these methods
        since they are called directly from receiving thread. This is a design choice,
        start another thread if you need to do such a thing.
        """
        params = ua.CreateSubscriptionParameters()
        params.RequestedPublishingInterval = period
        params.RequestedLifetimeCount = 3000
        params.RequestedMaxKeepAliveCount = 10000
        params.MaxNotificationsPerPublish = 10000
        params.PublishingEnabled = True
        params.Priority = 0
        return Subscription(self.uaclient, params, handler)

    def get_namespace_array(self):
        ns_node = self.get_node(ua.NodeId(ua.ObjectIds.Server_NamespaceArray))
        return ns_node.get_value()

    def get_namespace_index(self, uri):
        uries = self.get_namespace_array()
        return uries.index(uri)

    def delete_nodes(self, nodes, recursive=False):
        return delete_nodes(self.uaclient, nodes, recursive)
            


1	1	from __future__ import division # support for python2
2	1	from threading import Thread, Condition
3	1	import logging
4	1	try:
5	1	from urllib.parse import urlparse
6		except ImportError: # support for python2
7		from urlparse import urlparse
8
9	1	from opcua import ua
10	1	from opcua.client.ua_client import UaClient
11	1	from opcua.common.node import Node
12	1	from opcua.common.manage_nodes import delete_nodes
13	1	from opcua.common.subscription import Subscription
14	1	from opcua.common import utils
15	1	from opcua.crypto import security_policies
16	1	from opcua.common.shortcuts import Shortcuts
17	1	use_crypto = True
18	1	try:
19	1	from opcua.crypto import uacrypto
20		except ImportError:
21		print("cryptography is not installed, use of crypto disabled")
22		use_crypto = False
23
24
25	1	class KeepAlive(Thread):
26
27		"""
28		Used by Client to keep the session open.
29		OPCUA defines timeout both for sessions and secure channel
30		"""
31
32	1	def __init__(self, client, timeout):
33		"""
34		:param session_timeout: Timeout to re-new the session
35		in milliseconds.
36		"""
37	1	Thread.__init__(self)
38	1	self.logger = logging.getLogger(__name__)
39
40	1	self.client = client
41	1	self._dostop = False
42	1	self._cond = Condition()
43	1	self.timeout = timeout
44
45		# some server support no timeout, but we do not trust them
46	1	if self.timeout == 0:
47		self.timeout = 3600000 # 1 hour
48
49	1	def run(self):
50	1	self.logger.debug("starting keepalive thread with period of %s milliseconds", self.timeout)
51	1	server_state = self.client.get_node(ua.FourByteNodeId(ua.ObjectIds.Server_ServerStatus_State))
52	1	while not self._dostop:
53	1	with self._cond:
54	1	self._cond.wait(self.timeout / 1000)
55	1	if self._dostop:
56	1	break
57		self.logger.debug("renewing channel")
58		self.client.open_secure_channel(renew=True)
59		val = server_state.get_value()
60		self.logger.debug("server state is: %s ", val)
61	1	self.logger.debug("keepalive thread has stopped")
62
63	1	def stop(self):
64	1	self.logger.debug("stoping keepalive thread")
65	1	self._dostop = True
66	1	with self._cond:
67	1	self._cond.notify_all()
68
69
70	1	class Client(object):
71
72		"""
73		High level client to connect to an OPC-UA server.
74
75		This class makes it easy to connect and browse address space.
76		It attemps to expose as much functionality as possible
77		but if you want more flexibility it is possible and adviced to
78		use UaClient object, available as self.uaclient
79		which offers the raw OPC-UA services interface.
80		"""
81
82	1	def __init__(self, url, timeout=4):
83		"""
84
85		:param url: url of the server.
86		if you are unsure of url, write at least hostname
87		and port and call get_endpoints
88
89		:param timeout:
90		Each request sent to the server expects an answer within this
91		time. The timeout is specified in seconds.
92		"""
93	1	self.logger = logging.getLogger(__name__)
94	1	self.server_url = urlparse(url)
95	1	self.name = "Pure Python Client"
96	1	self.description = self.name
97	1	self.application_uri = "urn:freeopcua:client"
98	1	self.product_uri = "urn:freeopcua.github.no:client"
99	1	self.security_policy = ua.SecurityPolicy()
100	1	self.secure_channel_id = None
101	1	self.secure_channel_timeout = 3600000 # 1 hour
102	1	self.session_timeout = 3600000 # 1 hour
103	1	self._policy_ids = []
104	1	self.uaclient = UaClient(timeout)
105	1	self.user_certificate = None
106	1	self.user_private_key = None
107	1	self._session_counter = 1
108	1	self.keepalive = None
109	1	self.nodes = Shortcuts(self.uaclient)
110
111	1	def __enter__(self):
112	1	self.connect()
113	1	return self
114
115	1	def __exit__(self, exc_type, exc_value, traceback):
116	1	self.disconnect()
117
118	1	@staticmethod
119		def find_endpoint(endpoints, security_mode, policy_uri):
120		"""
121		Find endpoint with required security mode and policy URI
122		"""
123	1	for ep in endpoints:
124	1	if (ep.EndpointUrl.startswith(ua.OPC_TCP_SCHEME) and
125		ep.SecurityMode == security_mode and
126		ep.SecurityPolicyUri == policy_uri):
127	1	return ep
128	1	raise ua.UaError("No matching endpoints: {}, {}".format(
129		security_mode, policy_uri))
130
131	1	def set_security_string(self, string):
132		"""
133		Set SecureConnection mode. String format:
134		Policy,Mode,certificate,private_key[,server_private_key]
135		where Policy is Basic128Rsa15 or Basic256,
136		Mode is Sign or SignAndEncrypt
137		certificate, private_key and server_private_key are
138		paths to .pem or .der files
139		Call this before connect()
140		"""
141	1	if not string:
142		return
143	1	parts = string.split(',')
144	1	if len(parts) < 4:
145		raise ua.UaError('Wrong format: `{}`, expected at least 4 comma-separated values'.format(string))
146	1	policy_class = getattr(security_policies, 'SecurityPolicy' + parts[0])
147	1	mode = getattr(ua.MessageSecurityMode, parts[1])
148	1	return self.set_security(policy_class, parts[2], parts[3],
149		parts[4] if len(parts) >= 5 else None, mode)
150
151	1	def set_security(self, policy, certificate_path, private_key_path,
152		server_certificate_path=None,
153		mode=ua.MessageSecurityMode.SignAndEncrypt):
154		"""
155		Set SecureConnection mode.
156		Call this before connect()
157		"""
158	1	if server_certificate_path is None:
159		# load certificate from server's list of endpoints
160	1	endpoints = self.connect_and_get_server_endpoints()
161	1	endpoint = Client.find_endpoint(endpoints, mode, policy.URI)
162	1	server_cert = uacrypto.x509_from_der(endpoint.ServerCertificate)
163		else:
164		server_cert = uacrypto.load_certificate(server_certificate_path)
165	1	cert = uacrypto.load_certificate(certificate_path)
166	1	pk = uacrypto.load_private_key(private_key_path)
167	1	self.security_policy = policy(server_cert, cert, pk, mode)
168	1	self.uaclient.set_security(self.security_policy)
169
170	1	def load_client_certificate(self, path):
171		"""
172		load our certificate from file, either pem or der
173		"""
174		self.user_certificate = uacrypto.load_certificate(path)
175
176	1	def load_private_key(self, path):
177		"""
178		Load user private key. This is used for authenticating using certificate
179		"""
180		self.user_private_key = uacrypto.load_private_key(path)
181
182	1	def connect_and_get_server_endpoints(self):
183		"""
184		Connect, ask server for endpoints, and disconnect
185		"""
186	1	self.connect_socket()
187	1	self.send_hello()
188	1	self.open_secure_channel()
189	1	endpoints = self.get_endpoints()
190	1	self.close_secure_channel()
191	1	self.disconnect_socket()
192	1	return endpoints
193
194	1	def connect_and_find_servers(self):
195		"""
196		Connect, ask server for a list of known servers, and disconnect
197		"""
198		self.connect_socket()
199		self.send_hello()
200		self.open_secure_channel() # spec says it should not be necessary to open channel
201		servers = self.find_servers()
202		self.close_secure_channel()
203		self.disconnect_socket()
204		return servers
205
206	1	def connect_and_find_servers_on_network(self):
207		"""
208		Connect, ask server for a list of known servers on network, and disconnect
209		"""
210		self.connect_socket()
211		self.send_hello()
212		self.open_secure_channel()
213		servers = self.find_servers_on_network()
214		self.close_secure_channel()
215		self.disconnect_socket()
216		return servers
217
218	1	def connect(self):
219		"""
220		High level method
221		Connect, create and activate session
222		"""
223	1	self.connect_socket()
224	1	self.send_hello()
225	1	self.open_secure_channel()
226	1	self.create_session()
227	1	self.activate_session(username=self.server_url.username, password=self.server_url.password, certificate=self.user_certificate)
228
229	1	def disconnect(self):
230		"""
231		High level method
232		Close session, secure channel and socket
233		"""
234	1	self.close_session()
235	1	self.close_secure_channel()
236	1	self.disconnect_socket()
237
238	1	def connect_socket(self):
239		"""
240		connect to socket defined in url
241		"""
242	1	self.uaclient.connect_socket(self.server_url.hostname, self.server_url.port)
243
244	1	def disconnect_socket(self):
245	1	self.uaclient.disconnect_socket()
246
247	1	def send_hello(self):
248		"""
249		Send OPC-UA hello to server
250		"""
251	1	ack = self.uaclient.send_hello(self.server_url.geturl())
252		# FIXME check ack
253
254	1	def open_secure_channel(self, renew=False):
255		"""
256		Open secure channel, if renew is True, renew channel
257		"""
258	1	params = ua.OpenSecureChannelParameters()
259	1	params.ClientProtocolVersion = 0
260	1	params.RequestType = ua.SecurityTokenRequestType.Issue
261	1	if renew:
262		params.RequestType = ua.SecurityTokenRequestType.Renew
263	1	params.SecurityMode = self.security_policy.Mode
264	1	params.RequestedLifetime = self.secure_channel_timeout
265	1	nonce = utils.create_nonce(self.security_policy.symmetric_key_size) # length should be equal to the length of key of symmetric encryption
266	1	params.ClientNonce = nonce # this nonce is used to create a symmetric key
267	1	result = self.uaclient.open_secure_channel(params)
268	1	self.security_policy.make_symmetric_key(nonce, result.ServerNonce)
269	1	self.secure_channel_timeout = result.SecurityToken.RevisedLifetime
270
271	1	def close_secure_channel(self):
272	1	return self.uaclient.close_secure_channel()
273
274	1	def get_endpoints(self):
275	1	params = ua.GetEndpointsParameters()
276	1	params.EndpointUrl = self.server_url.geturl()
277	1	return self.uaclient.get_endpoints(params)
278
279	1	def register_server(self, server, discovery_configuration=None):
280		"""
281		register a server to discovery server
282		if discovery_configuration is provided, the newer register_server2 service call is used
283		"""
284	1	serv = ua.RegisteredServer()
285	1	serv.ServerUri = server.application_uri
286	1	serv.ProductUri = server.product_uri
287	1	serv.DiscoveryUrls = [server.endpoint.geturl()]
288	1	serv.ServerType = server.application_type
289	1	serv.ServerNames = [ua.LocalizedText(server.name)]
290	1	serv.IsOnline = True
291	1	if discovery_configuration:
292		params = ua.RegisterServer2Parameters()
293		params.Server = serv
294		params.DiscoveryConfiguration = discovery_configuration
295		return self.uaclient.register_server2(params)
296		else:
297	1	return self.uaclient.register_server(serv)
298
299	1	def find_servers(self, uris=None):
300		"""
301		send a FindServer request to the server. The answer should be a list of
302		servers the server knows about
303		A list of uris can be provided, only server having matching uris will be returned
304		"""
305	1	if uris is None:
306	1	uris = []
307	1	params = ua.FindServersParameters()
308	1	params.EndpointUrl = self.server_url.geturl()
309	1	params.ServerUris = uris
310	1	return self.uaclient.find_servers(params)
311
312	1	def find_servers_on_network(self):
313		params = ua.FindServersOnNetworkParameters()
314		return self.uaclient.find_servers_on_network(params)
315
316	1	def create_session(self):
317		"""
318		send a CreateSessionRequest to server with reasonable parameters.
319		If you want o modify settings look at code of this methods
320		and make your own
321		"""
322	1	desc = ua.ApplicationDescription()
323	1	desc.ApplicationUri = self.application_uri
324	1	desc.ProductUri = self.product_uri
325	1	desc.ApplicationName = ua.LocalizedText(self.name)
326	1	desc.ApplicationType = ua.ApplicationType.Client
327
328	1	params = ua.CreateSessionParameters()
329	1	nonce = utils.create_nonce(32) # at least 32 random bytes for server to prove possession of private key (specs part 4, 5.6.2.2)
330	1	params.ClientNonce = nonce
331	1	params.ClientCertificate = self.security_policy.client_certificate
332	1	params.ClientDescription = desc
333	1	params.EndpointUrl = self.server_url.geturl()
334	1	params.SessionName = self.description + " Session" + str(self._session_counter)
335	1	params.RequestedSessionTimeout = 3600000
336	1	params.MaxResponseMessageSize = 0 # means no max size
337	1	response = self.uaclient.create_session(params)
338	1	if self.security_policy.client_certificate is None:
339	1	data = nonce
340		else:
341	1	data = self.security_policy.client_certificate + nonce
342	1	self.security_policy.asymmetric_cryptography.verify(data, response.ServerSignature.Signature)
343	1	self._server_nonce = response.ServerNonce
344	1	if not self.security_policy.server_certificate:
345	1	self.security_policy.server_certificate = response.ServerCertificate
346	1	elif self.security_policy.server_certificate != response.ServerCertificate:
347		raise ua.UaError("Server certificate mismatch")
348		# remember PolicyId's: we will use them in activate_session()
349	1	ep = Client.find_endpoint(response.ServerEndpoints, self.security_policy.Mode, self.security_policy.URI)
350	1	self._policy_ids = ep.UserIdentityTokens
351	1	self.session_timeout = response.RevisedSessionTimeout
352	1	self.keepalive = KeepAlive(self, min(self.session_timeout, self.secure_channel_timeout) * 0.7) # 0.7 is from spec
353	1	self.keepalive.start()
354	1	return response
355
356	1	def server_policy_id(self, token_type, default):
357		"""
358		Find PolicyId of server's UserTokenPolicy by token_type.
359		Return default if there's no matching UserTokenPolicy.
360		"""
361	1	for policy in self._policy_ids:
362	1	if policy.TokenType == token_type:
363	1	return policy.PolicyId
364		return default
365
366	1	def server_policy_uri(self, token_type):
367		"""
368		Find SecurityPolicyUri of server's UserTokenPolicy by token_type.
369		If SecurityPolicyUri is empty, use default SecurityPolicyUri
370		of the endpoint
371		"""
372	1	for policy in self._policy_ids:
373	1	if policy.TokenType == token_type:
374	1	if policy.SecurityPolicyUri:
375		return policy.SecurityPolicyUri
376		else: # empty URI means "use this endpoint's policy URI"
377	1	return self.security_policy.URI
378		return self.security_policy.URI
379
380	1	def activate_session(self, username=None, password=None, certificate=None):
381		"""
382		Activate session using either username and password or private_key
383		"""
384	1	params = ua.ActivateSessionParameters()
385	1	challenge = b""
386	1	if self.security_policy.server_certificate is not None:
387	1	challenge += self.security_policy.server_certificate
388	1	if self._server_nonce is not None:
389	1	challenge += self._server_nonce
390	1	params.ClientSignature.Algorithm = b"http://www.w3.org/2000/09/xmldsig#rsa-sha1"
391	1	params.ClientSignature.Signature = self.security_policy.asymmetric_cryptography.signature(challenge)
392	1	params.LocaleIds.append("en")
393	1	if not username and not certificate:
394	1	self._add_anonymous_auth(params)
395	1	elif certificate:
396		self._add_certificate_auth(params, certificate, challenge)
397		else:
398	1	self._add_user_auth(params, username, password)
399	1	return self.uaclient.activate_session(params)
400
401	1	def _add_anonymous_auth(self, params):
402	1	params.UserIdentityToken = ua.AnonymousIdentityToken()
403	1	params.UserIdentityToken.PolicyId = self.server_policy_id(ua.UserTokenType.Anonymous, b"anonymous")
404
405	1	def _add_certificate_auth(self, params, certificate, challenge):
406		params.UserIdentityToken = ua.X509IdentityToken()
407		params.UserIdentityToken.PolicyId = self.server_policy_id(ua.UserTokenType.Certificate, b"certificate_basic256")
408		params.UserIdentityToken.CertificateData = uacrypto.der_from_x509(certificate)
409		# specs part 4, 5.6.3.1: the data to sign is created by appending
410		# the last serverNonce to the serverCertificate
411		sig = uacrypto.sign_sha1(self.user_private_key, challenge)
412		params.UserTokenSignature = ua.SignatureData()
413		params.UserTokenSignature.Algorithm = b"http://www.w3.org/2000/09/xmldsig#rsa-sha1"
414		params.UserTokenSignature.Signature = sig
415
416	1	def _add_user_auth(self, params, username, password):
417	1	params.UserIdentityToken = ua.UserNameIdentityToken()
418	1	params.UserIdentityToken.UserName = username
419	1	policy_uri = self.server_policy_uri(ua.UserTokenType.UserName)
420	1	if not policy_uri or policy_uri == security_policies.POLICY_NONE_URI:
421		# see specs part 4, 7.36.3: if the token is NOT encrypted,
422		# then the password only contains UTF-8 encoded password
423		# and EncryptionAlgorithm is null
424	1	if self.server_url.password:
425		self.logger.warning("Sending plain-text password")
426		params.UserIdentityToken.Password = password
427	1	params.UserIdentityToken.EncryptionAlgorithm = ''
428		elif self.server_url.password:
429		data, uri = self._encrypt_password(password, policy_uri)
430		params.UserIdentityToken.Password = data
431		params.UserIdentityToken.EncryptionAlgorithm = uri
432	1	params.UserIdentityToken.PolicyId = self.server_policy_id(ua.UserTokenType.UserName, b"username_basic256")
433
434	1	def _encrypt_password(self, password, policy_uri):
435		pubkey = uacrypto.x509_from_der(self.security_policy.server_certificate).public_key()
436		# see specs part 4, 7.36.3: if the token is encrypted, password
437		# shall be converted to UTF-8 and serialized with server nonce
438		passwd = password.encode("utf8")
439		if self._server_nonce is not None:
440		passwd += self._server_nonce
441		etoken = ua.ua_binary.Primitives.Bytes.pack(passwd)
442		data, uri = security_policies.encrypt_asymmetric(pubkey, etoken, policy_uri)
443		return data, uri
444
445	1	def close_session(self):
446		"""
447		Close session
448		"""
449	1	if self.keepalive:
450	1	self.keepalive.stop()
451	1	return self.uaclient.close_session(True)
452
453	1	def get_root_node(self):
454	1	return self.get_node(ua.TwoByteNodeId(ua.ObjectIds.RootFolder))
455
456	1	def get_objects_node(self):
457	1	return self.get_node(ua.TwoByteNodeId(ua.ObjectIds.ObjectsFolder))
458
459	1	def get_server_node(self):
460	1	return self.get_node(ua.FourByteNodeId(ua.ObjectIds.Server))
461
462	1	def get_node(self, nodeid):
463		"""
464		Get node using NodeId object or a string representing a NodeId
465		"""
466	1	return Node(self.uaclient, nodeid)
467
468	1	def create_subscription(self, period, handler):
469		"""
470		Create a subscription.
471		returns a Subscription object which allow
472		to subscribe to events or data on server
473		handler argument is a class with data_change and/or event methods.
474		These methods will be called when notfication from server are received.
475		See example-client.py.
476		Do not do expensive/slow or network operation from these methods
477		since they are called directly from receiving thread. This is a design choice,
478		start another thread if you need to do such a thing.
479		"""
480	1	params = ua.CreateSubscriptionParameters()
481	1	params.RequestedPublishingInterval = period
482	1	params.RequestedLifetimeCount = 3000
483	1	params.RequestedMaxKeepAliveCount = 10000
484	1	params.MaxNotificationsPerPublish = 10000
485	1	params.PublishingEnabled = True
486	1	params.Priority = 0
487	1	return Subscription(self.uaclient, params, handler)
488
489	1	def get_namespace_array(self):
490	1	ns_node = self.get_node(ua.NodeId(ua.ObjectIds.Server_NamespaceArray))
491	1	return ns_node.get_value()
492
493	1	def get_namespace_index(self, uri):
494	1	uries = self.get_namespace_array()
495	1	return uries.index(uri)
496
497	1	def delete_nodes(self, nodes, recursive=False):
498	1	return delete_nodes(self.uaclient, nodes, recursive)
499
500

FreeOpcUa / python-opcua

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Client.open_secure_channel() A

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