Matter Linux Fabric Bridge Example

An example application to implement the Aggregator device type with Fabric Synchronization condition met and demonstrates the end-to-end Fabric Synchronization feature using dynamic endpoints.

Fabric Synchronization feature will facilitate the commissioning of end devices from one fabric to another without requiring user intervention for every end device. It defines mechanisms that can be used by multiple ecosystems/controllers to communicate with one another to simplify the experience for users.

This doc is tested on Ubuntu 22.04 LTS (aarch64)

• Matter Linux Fabric Bridge Example
  • Theory of Operation
  • Building
  • Running the Complete Example on Ubuntu

Theory of Operation

Dynamic Endpoints

The Bridge Example makes use of Dynamic Endpoints. Current SDK support is limited for dynamic endpoints, since endpoints are typically defined (along with the clusters and attributes they contain) in a .zap file which then generates code and static structures to define the endpoints.

To support endpoints that are not statically defined, the ZCL attribute storage mechanisms will hold additional endpoint information for NUM_DYNAMIC_ENDPOINTS additional endpoints. These additional endpoint structures must be defined by the application and can change at runtime.

To facilitate the creation of these endpoint structures, several macros are defined:

DECLARE_DYNAMIC_ATTRIBUTE_LIST_BEGIN(attrListName) DECLARE_DYNAMIC_ATTRIBUTE(attId, attType, attSizeBytes, attrMask) DECLARE_DYNAMIC_ATTRIBUTE_LIST_END(clusterRevision)

• These three macros are used to declare a list of attributes for use within a cluster. The declaration must begin with the DECLARE_DYNAMIC_ATTRIBUTE_LIST_BEGIN macro which will define the name of the allocated attribute structure. Each attribute is then added by the DECLARE_DYNAMIC_ATTRIBUTE macro. Finally, DECLARE_DYNAMIC_ATTRIBUTE_LIST_END macro should be used to close the definition.

• All attributes defined with these macros will be configured as ATTRIBUTE_MASK_EXTERNAL_STORAGE in the ZCL database and therefore will rely on the application to maintain storage for the attribute. Consequently, reads or writes to these attributes must be handled within the application by the emberAfExternalAttributeWriteCallback and emberAfExternalAttributeReadCallback functions. See the bridge application's main.cpp for an example of this implementation.

DECLARE_DYNAMIC_CLUSTER_LIST_BEGIN(clusterListName) DECLARE_DYNAMIC_CLUSTER(clusterId, clusterAttrs, role, incomingCommands, outgoingCommands) DECLARE_DYNAMIC_CLUSTER_LIST_END

• These three macros are used to declare a list of clusters for use within a endpoint. The declaration must begin with the DECLARE_DYNAMIC_CLUSTER_LIST_BEGIN macro which will define the name of the allocated cluster structure. Each cluster is then added by the DECLARE_DYNAMIC_CLUSTER macro referencing attribute list previously defined by the DECLARE_DYNAMIC_ATTRIBUTE... macros and the lists of incoming/outgoing commands terminated by kInvalidCommandId (or nullptr if there aren't any commands in the list). Finally, DECLARE_DYNAMIC_CLUSTER_LIST_END macro should be used to close the definition.

DECLARE_DYNAMIC_ENDPOINT(endpointName, clusterList)

• This macro is used to declare an endpoint and its associated cluster list, which must be previously defined by the DECLARE_DYNAMIC_CLUSTER... macros.

Building

• Install tool chain

  sudo apt-get install git gcc g++ python pkg-config libssl-dev libdbus-1-dev libglib2.0-dev ninja-build python3-venv python3-dev unzip
  

• Build the example application:

  For Linux host example:

  ./scripts/examples/gn_build_example.sh examples/fabric-bridge-app/linux out/debug/standalone chip_config_network_layer_ble=false 'import("//with_pw_rpc.gni")'
  

  For Raspberry Pi 4 example:

  Pull Docker Images

  docker pull connectedhomeip/chip-build-vscode:latest
  

  Run docker

  docker run -it -v ~/connectedhomeip:/var/connectedhomeip connectedhomeip/chip-build-vscode:latest /bin/bash
  

  Build

  cd /var/connectedhomeip
  
  git config --global --add safe.directory /var/connectedhomeip
  git config --global --add safe.directory /var/connectedhomeip/third_party/pigweed/repo
  git config --global --add safe.directory /var/connectedhomeip/examples/common/QRCode/repo
  
  ./scripts/run_in_build_env.sh \
   "./scripts/build/build_examples.py \
      --target linux-arm64-fabric-bridge-no-ble-clang-rpc \
      build"
  

  Transfer the fabric-bridge-app binary to a Raspberry Pi

  scp ./fabric-bridge-app ubuntu@xxx.xxx.xxx.xxx:/home/ubuntu
  

• To delete generated executable, libraries and object files use:

  cd ~/connectedhomeip/examples/fabric-bridge-app/linux
  rm -rf out/
  

Running the Complete Example on Ubuntu

• Building

  Follow Building section of this document.

• Run Linux Fabric Bridge Example App

  cd ~/connectedhomeip/examples/fabric-bridge-app/linux
  sudo out/debug/fabric-bridge-app
  

• Test the device using FabricAdmin on your laptop / workstation etc.