..
    Copyright 2019 NXP


.. _opc-ua-open62541-demo:

==================================================
OPC UA (Open62541) Demo
==================================================

Supported Platforms
=======================================================

* Server Platform

  * Windows – JRCPv2 – SE050
  * iMX6 / RaspberryPi - t1oi2c – SE050

* Client Platform

  * UaExpert on Windows
  * Open62541 client on Windows
  * Open62541 client on iMX6 / RaspberryPi

Introduction
==============

OPC UA (Open Platform Communications Unified Architecture) is an application layer protocol specific to Industrial IoT.
It can run on top of TCP, TCP + Web services or TCP + HTTPS.
In this client - server demo, the Open62541 open source OPC UA stack is used for integration with SE050.
The server certificate and key are provisioned inside the SE050, the access to the SE050 is is performed using the SSS APIs.
The OPC UA server example source code is available in directory ``demos\opc_ua\opc_ua_server``.
The Open62541 specific adaptation layer to the SE050 is available in directory ``sss\plugin\open62541``.
The source code of the Open62541 stack is available in directory ``ext\open62541``.

OPC UA stack:

.. image:: security.jpg

In reference to the above image the demo matches the left arrow:

- UA binary encoding is used
- UA Secure conversation with security policy ``Basic256Sha256``  and ``Sign and Encrypt mode``
- on top of TCP

.. image:: open62541_sss.jpg

The crypto functionality (as defined by ``Basic256Sha256``) is handled as follows:

- AsymmetricSignatureAlgorithm_RSA-PKCS15-SHA2-256: RSA Sign operation done by SE050
- AsymmetricEncryptionAlgorithm_RSA-OAEP-SHA: RSA Decrypt operation done by SE050
- Symmetric crypto operations are handled by the OPC UA stack on the host micro

Build Open62541 server and client examples
============================================

1) Build server and client example ::

    cd simw-top
    python3 scripts/create_cmake_projects.py
    cd ../simw-top_build/imx_native_se050_t1oi2c
    cmake -DWithOPCUA_open62541:BOOL=ON -DHostCrypto:STRING=MBEDTLS -DWithSharedLIB:BOOL=OFF .
    cmake --build .
    make install
    ldconfig /usr/local/lib

.. note::
    Replace ``imx_native_se050_t1oi2c`` with ``raspbian_native_se050_t1oi2c``
    when building for Raspberry Pi.

#) Server and client binaries are copied to the simw-top/tools folder


Test Open62541 server and client examples
=========================================

1) Client/Server keys are available in ``simw-top\demos\opc_ua\credentials\``. Optionally you can regenerate the client/server keys
   with the following command ::

	cd simw-top/demos/opc_ua/scripts
	python3 createOPCUACredentials_Optional.py

	OPU UA mandates the host name to be part of the subjectAltName in the server certificate.
	The default server certificate provided with the package uses hostname 'localhost'.
	To create a completely new set of credentials with a specific server hostname / ip-address run
	createOPCUACredentials_Optional.py script as

	python3 createOPCUACredentials_Optional.py <server_hostname>    # Default <server_hostname> = localhost

#) Refer to :ref:`cli-tool` for ssscli tool setup. Using ssscli tool, provision server certificate and key into SE050 and create a reference pem file for server key ::

	cd simw-top/demos/opc_ua/scripts

	python3 provisionOPCUAServer.py 127.0.0.1:8050 jrcpv2   #On Windows
	OR
	python3 provisionOPCUAServer.py                         #On iMX6 / RaspberryPi

#) Start opc ua server ::

	cd simw-top/demos/opc_ua/scripts

	python3 open62541Server.py jrcpv2 127.0.0.1:8050 <certificate>  #On Windows
	OR
	python3 open62541Server.py <certificate>                        #On iMX6 / RaspberryPi

	When using Open62541 client:
	    <certificate> is located at simw-top\demos\opc_ua\credentials\open62541_client_cert.der
	When using UAexpert client:
	    <certificate> is located at uaexpert\PKI\own\certs\uaexpert.der

	Passing "none" for <certificate>, will make the server accept all client certificates.

#) Start opc ua client ::

	cd simw-top/demos/opc_ua/scripts
	python3 open62541Client.py opc.tcp://127.0.0.1:4840

	On successful connection, value of the object "Sensor1" is read from server and displayed.


#) UaExpert client can also be used to test the Open62541 server.

- For testing with UaExpert client, root certificate needs to be copied to UaExpert trusted list of certificates,

- Go to UaExpert -> Settings -> Manage Certificates -> Trusted (Tab) -> Open Certificate Location and copy the file ``simw-top\demos\opc_ua\credentials\open62541_rootCA_cert.der``

- Also disable following errors in UaExpert configurations.
	i. UaExpert -> Settings -> Configure UaExpert -> General.DisableError.CertificateIssuerRevocationUnknown -> true
	#. UaExpert -> Settings -> Configure UaExpert -> General.DisableError.CertificateRevocationUnknown -> true

- Add the server details to connect. UaExpert -> Server -> Add -> Advanced (Tab). Add details in
	i. EndPoint Url (opc.tcp://<SERVER_IP>:4840/)
	#. Security Policy as Basic256Sha256
	#. Message Security Mode as Sign & Encrypt

- Added server will appear in project tab. Right click on server -> Connect.

- On successful connection, the client objects should appear in UaExpert address space.

- To change the value of object "Sensor1", select the object "Sensor1" in address space. In the Attribute section, select "value" attribute and enter the new value.


Known Limitations
===================

1) Client certificates are self signed certificates. Not tested with root ca signed.

#) No root certificate can be given as input to command line Open62541 client. So any server certificate is accepted.


.. only:: nxp

	.. include:: nxpint-readme.rst.txt