UA-LDS

The OPC Foundation has formally released the OPC Unified Architecture Local Discovery Server to the community.

Please review official site page (https://OPCFoundation.github.io/UA-LDS/) for:

• Overview
• Licensing

Official installations for Windows are built by the OPC Foundation and provided at the OPC Foundation website (https://opcfoundation.org/).

Contributing

We strongly encourage community participation and contribution to this project. First, please fork the repository and commit your changes there. Once happy with your changes you can generate a 'pull request'.

You must agree to the contributor license agreement before we can accept your changes. The CLA and "I AGREE" button is automatically displayed when you perform the pull request. You can preview CLA here.

OPC UA, empowering the Industrial Internet of Things (IIOT) and Industrie 4.0.

Building and running the LDS

Build Dependencies

• OPC UA Ansi C Stack v1.04.342. (included) Please review official site page http://opcfoundation.github.io/UA-AnsiC-Legacy.
• CMake version v3.6.2 (or later) from https://cmake.org/install/.
• Perl
• Windows:
  • OpenSSL v3.1.4 was used in development and testing: either built from source (https://www.openssl.org/source/) or as pre-built package, for example from https://slproweb.com/products/Win32OpenSSL.html.
  • Bonjour Mdns/dnssd (Multicast Domain Name System) client library (included)
• Linux:
  • OpenSSL v3.x.x, v1.1.1 and v1.0.2 was used in development and testing : (sudo apt-get install libssl-dev) (sudo yum install openssl-devel)
  • Avahi v0.61 (or later) libdnssd compatibility layer: (sudo apt-get install libavahi-compat-libdnssd-dev) (sudo yum install avahi-compat-libdns_sd-devel)

Building the LDS

Make sure that openssl is installed or build. See UA-AnsiC build instructions.
Predefined scripts are available based on CMake.

• Windows: build_ualds.bat (Visual Studio Command Shell)
• Linux: build_linux.sh

Runtime Dependencies

• Windows: Bonjour Service (576.30.4)
• Linux: Avahi Daemon (0.61 or later)

After a successful build, binary files will be in \bin[config] and should work as is.

Running on Linux using Docker

Make sure the avahi-daemon on your host system is either disabled or not installed at all. To remove the avahi-daemon from your host run

sudo apt purge avahi-daemon

To only stop and disable the avahi-daemon on your host run

sudo systemctl stop avahi-daemon
sudo systemctl disable avahi-daemon

Finally verify no other service is using the mDNS Port 5353/udp or LDS Port 4840/tcp by running sudo netstat -tulnp. To run the LDS clone the repository and follow the steps described either in Docker or in Docker Compose. Regardless of whether Docker or Docker Compose is chosen the LDS will be using three directory mounts to make its data accessible:

• ./UALDS-data/config: contains the servers config file ualds.conf
• ./UALDS/pki: contains the LDS's public key infrastructure
• ./UALDS/logs: contains all the containers logs files

Docker Compose (Recommended)

After completing the prerequisites build and execute the image by running docker compose up -d. By default the docker-compose.yml defines the network_mode=host to ensure your LDS broadcasts the proper hostname via mDNS in your network. If you can not use network_mode=host you can comment it out and uncomment the ports and hostname lines within the docker-compose.yml file and enter the correct hostname there.

Docker

First build the image using the provided Dockerfile.

docker build -t lds .

Running in host mode (shared network interface with host):

docker run -d -v ./UALDS-data/config:/lds/etc -v ./UALDS-data/pki:/opt/opcfoundation/ualds/pki -v ./UALDS-data/logs:/var/log/ --network host --restart always --name lds lds:latest

Running in a separate docker network (Replace with your actual hostname):

docker run -d -v ./UALDS-data/config:/lds/etc -v ./UALDS-data/pki:/opt/opcfoundation/ualds/pki -v ./UALDS-data/logs:/var/log/ -h <hostname> -p 5353:5353/udp -p 4840:4840 --restart always --name lds lds:latest

Package file structure description

The following tree shows the directory layout of this repo:

- /-- ualds                      LDS platform independent code
- |  |- stack                    OPC UA Ansi C Stack (https://github.com/OPCFoundation/UA-AnsiC-Legacy)
- |    ||- stack
- |      |||- core                  Configuration and utilities
- |      |||- platforms
- |        ||||- linux              Platform adaption to OpenSSL and linux API
- |        ||||- win32              Platform adaption to OpenSSL and Win32 API
- |      |||- proxystub
- |      |||- clientproxy           Client side top level API (optional)
- |      |||- serverstub            Server side top level API (optional)
- |      |||- securechannel         OPC UA secure conversation
- |      |||- stackcore             Base types and interfaces
- |      |||- transport
- |        ||||- https              HTTPS transport (optional)
- |        ||||- tcp                OPC TCP Binary transport
- |  |- dnssd                    mdnsresponder (Bonjour) client library (Windows)
- |  |- win32                    Local Discovery Server Windows platform implementation
- |  |- linux                    Local Discovery Server Linux platform implementation

Third party Notices and Licenses

Open Source Software

Required notices for open source software products or components distributed with OPC Foundation's Local Discovery Server (LDS-ME) are identified in the following table along with the applicable licensing information. Additional notices and/or licenses may be found in the included documentation or readme files of the individual third party open source software.

Provider	Component	Licensing Information
Apple Computer, Inc.	Bonjour Mdns/dnssd (Multicast Domain Name System) client library	Apache License v2 http://www.apache.org/licenses/LICENSE-2.0.html
Open SSL Project	OpenSSL 3.1.4	Apache License v2 https://www.openssl.org/source/license.html
github.com/lathiat/avahi	Avahi 0.61	GNU Lesser General Public License v2.1 Avahi was developed by Lennart Poettering and Trent Lloyd. It is the result of a merger of Poettering's original mDNS/DNS-SD implementation called "FlexMDNS", and Lloyd's original code called "Avahi" https://github.com/lathiat/avahi/blob/master/LICENSE