1 Connect IDE to Runtime

     2 ======================

     3 

     4 

     5 Connection is described by the *URI_location* in project's configuration.

     6     ``Open project tree root -> Config tab -> URI_location``

     7 

     8 eRPC

     9 ----

    10 

    11 `eRPC <https://github.com/embeddedrpc/erpc>`_ (Embedded RPC) is an open source

    12 Remote Procedure Call (RPC) developed by NXP. 

    13 

    14 In case of Beremiz, Runtime is the eRPC server and IDE is a client. Transport

    15 can be either TCP/IP or Serial.

    16 

    17 ``URI_location`` for eRPC:

    18 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^

    19     * ``ERPC://host[:port]`` unencrypted connection. Default port is 3000.

    20         This connection is highly unsecure, and should never be used on

    21         untrusted network. It is intended to be used on peer to peer connection

    22         such as ethernet over USB, for initial pairing with IDE.

    23     * ``ERPCS://host[:port]`` SSL-PSK encrypted connection.

    24         Default port is 4000.

    25     * ``LOCAL://`` starts local runtime and connect with it through TCP/IP

    26         bound to Localhost using random port.

    27 

    28 SSL-PSK setup:

    29 ^^^^^^^^^^^^^^

    30 

    31 In order to provide practical secure communication in between runtime and IDE

    32 TLS-PSK connection according to rfc4279.

    33 

    34 Server (runtime)

    35 """"""""""""""""

    36 .. highlight:: ini

    37 

    38 PSK ciphersuite avoids the need for public key operations and certificate

    39 management. It is perfect for a performance-constrained environments with

    40 limited CPU power as a PLC.

    41 

    42 `Stunnel <https://www.stunnel.org/>`_ is used to wrap unencrypted eRPC server

    43 into an TLS-PSK SSL socket. Hereafter is ``stunnel.conf``::

    44 

    45     [ERPCPSK]

    46     accept = 4000

    47     connect = 127.0.0.1:3000

    48     ciphers = PSK

    49     sslVersion = TLSv1.2

    50     PSKsecrets = psk.txt

    51 

    52 .. highlight:: text

    53 

    54 List PSK ciphers available in server's openssl::

    55 

    56     openssl ciphers -s -psk -tls1_2

    57 

    58 Launch ``stunnel``::

    59 

    60     stunnel ./stunnel.conf

    61 

    62 Client (IDE) 

    63 """"""""""""

    64 

    65 Compare client's available openssl PSK ciphers with Server's ciphers. At least

    66 a few of them should match::

    67 

    68     openssl ciphers -s -psk -tls1_2

    69 

    70 Use unencrypted peer-to-peer connection such as network over USB 

    71 or simple Ethernet cable, connect an obtain PSK::

    72 

    73     ERPC://hostname[:port]

    74 

    75 Then use Identity Management dialog in IDE to select matching ID and generate

    76 ``ERPCS`` URI::

    77 

    78     ERPCS://hostname[:port]#ID

    79 

    80 

    81 WAMP

    82 ----

    83 

    84 `WAMP <https://wamp-proto.org/>`_ is an open standard WebSocket subprotocol that provides two application messaging 

    85 patterns in one unified protocol: Remote Procedure Calls + Publish & Subscribe.

    86 

    87 Beremiz WAMP connector implementation uses python ``autobahn`` module, from the `crossbar.io <https://github.com/crossbario>`_ project.

    88 

    89 Both IDE and runtime are WAMP clients that connect to ``crossbar`` server through HTTP.

    90 

    91 ``URI_location`` for WAMP:

    92 	* ``WAMP://host[:port]#realm#ID`` Websocket over unencrypted HTTP transport.

    93 	* ``WAMPS://host[:port]#realm#ID`` Websocket over secure HTTPS transport.

    94 

    95 

    96 ..

    97     TODO : 

    98         crossbar server setup with example config and minimal backend.