Edge

This document contains the instructions for using and developing Edge.

The full Edge documentation is part of our Device Management documentation site, where you can also find the API documentation. For comments or questions about the documentation, please email us.

License

This software is provided under Apache 2.0 license.

Content

The contents of the repository.

Folders

Folder name	Contents
cmake	CMake scripts
common	Common functionality of edge-core and pt-client.
config	The configuration files location.
edge-client	A wrapper used to integrate Edge with Device Management Client.
edge-core	Edge Core server process.
edge-rpc	Common RPC functionality of edge-core and pt-client.
edge-tool	A helper tool to observe and manipulate Edge mediated resources.
fota	Firmware update callback function defintions.
include	Header files for Edge.
lib	Edge library dependencies
pt-client	Deprecated Protocol translator client v1 stub.
pt-client-2	Protocol translator client v2 stub.
test	Unit tests.

Files

File name	Description
CMakeLists.txt	The root CMakeLists file.
git_details.cmake	CMake file used for generating the version information.
config/mbed_cloud_client_user_config.h	A configuration file for the Device Management Client settings.
config/mbedtls_mbed_client_config.h	A configuration file for Mbed TLS.

Build and run

1. Directly on Ubuntu 22.04 or 20.04, or
2. Using Docker.

Install these in Ubuntu 22.04 or 20.04:

1. Prerequisites

   sudo apt install build-essential clang cmake curl doxygen gcc git graphviz libc6-dev libclang-dev libcurl4-openssl-dev libgpiod-dev libmosquitto-dev mosquitto-clients pkg-config python3 python3-pip python3-venv

   For debugging, install also these:

   sudo apt install lcov gcovr valgrind

   For documentation, install also these:

   sudo apt install doxygen graphviz

2. Initialize repositories

   Fetch the Git submodules that are direct dependencies for Edge.

   git submodule update --init --recursive

3. Install Rust

   Note: This is required only when building with Parsec.

   curl https://sh.rustup.rs -sSf | bash -s -- -y
   
   # configure the PATH environment variable
   export PATH=$PATH:~/.cargo/bin
   
   # To verify, run
   rustc --version
   cargo version

Using Docker

First, fetch the dependencies

git submodule update --init --recursive

The edge-core docker image is a developer build with firmware update enabled. Thus, place the mbed_cloud_dev_credentials.c and update_default_resources.c in config folder before starting the build -

docker build -t edge-core:latest -f ./Dockerfile .

Alternatively, you can specify the location of the certificates as build arguments -

docker build --build-arg developer_certificate=./config/mbed_cloud_dev_credentials.c --build-arg update_certificate=./config/update_default_resources.c -t edge-core:latest -f ./Dockerfile .

Run the docker image. To restart the container from last known state of edge-core, mount the mcc_config folder to the host machine. Also, you can mount the default unix domain socket path /tmp/edge.sock to the host machine for other docker containers or service to establish the JSON-RPC websocket connection with this edge-core instance.

docker run -v $PWD/mcc_config:/usr/src/app/mbed-edge/mcc_config -v /tmp:/tmp edge-core:latest

For interactive bash session, run the following command -

docker run -it --entrypoint bash -v $PWD/mcc_config:/usr/src/app/mbed-edge/mcc_config -v /tmp:/tmp -v $PWD:/usr/src/app/mbed-edge edge-core:latest

Configuring Edge build

You can configure the build options for Device Management Client with the CMake command line flags. You can enable BYOC_MODE or DEVELOPER_MODE by giving a flag -DBYOC_MODE=ON or -DDEVELOPER_MODE=ON when creating the CMake build to insert the certificates to Edge during compilation. For factory provisioning, you need to give the mode -DFACTORY_MODE=ON.

mkdir build
cd build
cmake -DDEVELOPER_MODE=ON -DFIRMWARE_UPDATE=OFF ..
make

In order to have FIRMWARE_UPDATE enabled (ON) you must run the manifest-dev-tool to generate the update_default_resources.c file. For more information, see the documentation on enabling firmware updates.

With the BYOC_MODE it is possible to inject the Device Management Client configuration as CBOR file. The --cbor-conf argument takes the path to CBOR file. The edge-tool can be used to convert the C source file Device Management developer credentials file to CBOR format. See the instructions in edge-tool/README.md

Other build flags can also be set with this method.

Enabling firmware update

To use the firmware update functionality, you must generate a update_default_resources.c file.

You can create a update_default_resources.c file, using the manifest-dev-tool utility, by running:

manifest-dev-tool init

Move the created update_default_resources.c file to the config folder.

The command also creates a .update-certificates folder, which contains self-signed certificates that the manifest tool uses to sign resources and the manifest for the firmware update.

Note: The generated certificates are not secure for use in production environments. Please read the Provisioning devices for Device Management documentation on how to build a resource file and certificates safe for a production environment.

Version 0.15.0 introduces a new Firmware-Over-the-Air (FOTA) Update Framework library which extends the capability of the previous library aka Update Client (UC) Hub. Using the new library you can not only update the device itself but also push update to a component of the device. For instance, you can leverage the features of new library to update the firmware driver of a BLE or a WiFi module connected to the device managed by Izuma Networks. By default, UC Hub library is compiled into the binary. In order to switch to new FOTA library, add this CMake flag -DFOTA_ENABLE=ON during build time.

The FOTA Update Framework library uses curl to fetch the images. By default, the curl library is statically compiled. We also support dynamic linking and to enable that add this flag - -DMBED_CLOUD_CLIENT_CURL_DYNAMIC_LINK=ON during build time.

Hence, to enable the firmware update using new FOTA library and dynamically linking curl, pass the CMake -DFIRMWARE_UPDATE=ON, -DFOTA_ENABLE=ON and -DMBED_CLOUD_CLIENT_CURL_DYNAMIC_LINK=ON when you build Edge Core:

mkdir build
cd build
cmake -D[MODE] -DFIRMWARE_UPDATE=ON -DFOTA_ENABLE=ON -DMBED_CLOUD_CLIENT_CURL_DYNAMIC_LINK=ON ..
make

Alternatively, in order to use the UC hub library just compile with CMake -DFIRMWARE_UPDATE=ON flag.

In addition, you need to set the #define MBED_CLOUD_CLIENT_UPDATE_STORAGE. The exact value of the define depends on the used Linux distribution and the machine used to run Edge. For standard desktop Linux the value is set in cmake/edge_configure.cmake to a value ARM_UCP_LINUX_GENERIC.

Combined image update

Lets you group together multiple images on the device as requiring a simultaneous update. This is useful when the images have a strong dependency on each other during device boot in runtime. For instance, use this feature to update the boot and rootfs image of the gateway in a single update process. To enable it, add the flag -DFOTA_COMBINED_IMAGE_SUPPORT=ON during build time.

fota/fota_app_callbacks.c implements the callbacks to support the combined image update feature. For detailed information, follow this link.

Enabling Parsec

Parsec is the Platform Abstraction for Security, an open-source initiative, which provides a platform-agnostic interface for calling the secure storage and operation services of a trusted platform module (TPM) on Linux.

This lets you generate the device's bootstrap private key on a TPM during the factory flow. Later, when the device calls the Device Management bootstrap server, Device Management Client calls the Parsec API and uses the bootstrap key as part of the DTLS handshake, without having to export the key.

Now let's try building Parsec client and Edge core. Pass -DPARSEC_TPM_SE_SUPPORT=ON when you run the CMake build command:

mkdir build
cd build
cmake -DFACTORY_MODE=ON -DPARSEC_TPM_SE_SUPPORT=ON ..
make

Note: You can only work with Edge Core in factory mode when you use Parsec and a TPM.

Factory provisioning

Factory provisioning is the process of injecting the cryptographic credentials used to connect Edge to Device Management Cloud. For more information, read the Provisioning documentation.

Using your own certificate authority

To use your own certificate authority, add the following flag to the CMake command: -DBYOC_MODE=ON.

After this, you need to add a byoc_data.h file filled with the BYOC information to the edge-client folder.

Developer mode

To enable the developer mode, add the following flag to the CMake command: -DDEVELOPER_MODE=ON.

After this, you need to add the mbed_cloud_dev_credentials.c file to the config folder. You need a user account in Device Management Cloud to be able to generate a developer certificate. To obtain the developer certificate, follow these steps:

• Go to Device identity -> Security.
• Click actions and Generate developer certificate
• Give a name and an optional description to the certificate.
• Download the certificate file mbed_cloud_dev_credentials.c.

Expiration time configuration

To configure the expiration time from the default of one hour (3600 seconds), change the compile time define MBED_CLOUD_CLIENT_LIFETIME in the config/mbed_cloud_client_user_config.h file. The expiration time is inherited by the mediated endpoints from the Edge Core. You should set the expiration time to a meaningful value for your setup. For more the details of the expiration, read the Device Management Client documentation.

#define MBED_CLOUD_CLIENT_LIFETIME 3600

Configuring the maximum number of registered endpoints

Maximum number of registered endpoints can be configured by giving -DEDGE_REGISTERED_ENDPOINT_LIMIT=1000 when creating CMake build. The default limit is 500 endpoints.

mkdir build
cd build
cmake -D[MODE] -DFIRMWARE_UPDATE=[ON|OFF] -DEDGE_REGISTERED_ENDPOINT_LIMIT=10 ..
make

This value helps to limit the computation and memory resources usage. When this limit is reached, no more devices can be registered until some devices unregister.

Configuring the network interface

To help Edge Core to select the correct network interface, please set the correct value in the CMake command line -DEDGE_PRIMARY_NETWORK_INTERFACE_ID=eth0. Default value is eth0.

mkdir build
cd build
cmake -D[MODE] -DFIRMWARE_UPDATE=[ON|OFF] -DEDGE_REGISTERED_ENDPOINT_LIMIT=[LIMIT] -DEDGE_PRIMARY_NETWORK_INTERFACE_ID=eth0 ..
make

You can find the correct value for example using the Linux command ifconfig. Networking should mostly work with a fake interface ID. However, you need the correct interface ID for example for the UDP/server like functionality to get the correct IP address of the interface. Setting this value helps to select the best network interface if there are several available.

Configuring a reset factory settings GPIO

Edge Client has support for a local GPIO input to trigger a reset to factory settings (RFS).

This GPIO would typically be a physical button, which would need to be held for a period.

Specifically, if the specified GPIO transitions from inactive to active and back, with the active state held for more than ten seconds, an RFS is triggered as if initiated via a network command.

Support is enabled by adding -DRFS_GPIO=ON to the CMake command line, together with option(s) to specify which line.

The GPIO line can be specified in a few different ways:

• By line name only, searching all GPIO chips: -DRFS_GPIO_NAME=RFS_BUTTON
• By chip name, label or number, and line name: -DRFS_GPIO_CHIP=gpiochip3 -DRFS_GPIO_NAME=RFS_BUTTON
• By chip name, label or number, and line offset: -DRFS_GPIO_CHIP=80000000.gpio -DRFS_GPIO_OFFSET=0

Flags for the GPIO line request can be specified, for example by adding -DRFS_GPIO_FLAGS=GPIOD_LINE_REQUEST_FLAG_ACTIVE_LOW.

The required hold time for the GPIO can be modified from the default ten seconds using for example -DRFS_GPIO_HOLD_TIME=2.

Configuring the log messages

You change the verbosity of the log messages (useful for debugging) by giving -DTRACE_LEVEL=DEBUG when creating the CMake build:

mkdir build
cd build
cmake -D[MODE] -DTRACE_LEVEL=[DEBUG|INFO|WARN|ERROR] ..
make

Root of Trust device key generation

The Edge versions before CR-0.4.1 contained a Device Management Client versions from 1.2.x which had a defect in Root of Trust device key generation. The defect is fixed in 1.3.0 version of the Device Management Client but the fix is not backwards compatible. Use the compatibility flag only if you must have the compatibility and you accept the security issues it contains.

To preserve the compatibility with devices shipped with earlier versions of the key generation, a special compiler flag PAL_DEVICE_KEY_DERIVATION_BACKWARD_COMPATIBILITY_CALC was introduced. The default behavior is to use the new more secure way of generating the key.

If you want to enable the compatibility the flag has to be defined and the value of the flag set to 1.

The flag must be defined in the cmake/edge-configure.cmake:

add_definitions ("-DPAL_DEVICE_KEY_DERIVATION_BACKWARD_COMPATIBILITY_CALC=1")

Using custom targets

Custom targets can be set by creating custom cmake files to ./cmake/targets and ./cmake/toolchains-folders. The targets-folder is used for setting up the Edge build options, whereas the toolchains-folder is used for setting the build environment variables. After creating the custom cmake file, the ./cmake/edge_configure.cmake needs to be edited to include the new targets.

Building Edge Doxygen API

You can use the following commands to build the Doxygen documentation:

mkdir build-doc
cd build-doc
cmake -DBUILD_DOCUMENTATION=ON ..
make edge-doc

The generated documentation can be found from the build-doc/doxygen-folder.

General info for running the binaries

Before running any Protocol Translator clients, start Edge Core first, for example like following:

./edge-core --edge-pt-domain-socket <domain-socket> -o <http-port>

In the edge-core command, the edge-pt-domain-socket parameter is the domain socket path where the protocol translator connects to. The http-port parameter is the port that you can use for querying the status of Edge. The default domain socket path is /tmp/edge.sock (for the protocol translator API) and the default HTTP port is 8080 (for the HTTP status API).

To see other command line options, write:

./edge-core --help

When you run the edge-core the first time, it creates the folder ./mcc_config which is used for persistent storage settings for egde-core.

Note: The certificates injected in factory must match this configuration definition.

You can use the --reset-storage parameter to clear the settings in this folder when starting the server. This does not remove the devices and settings in the cloud. You need to remove them manually, for example using the Device Management Cloud Portal.

You can set the location of the configuration directory in your Edge target configuration file, for example: cmake/targets/default.cmake by changing the values of PAL_FS_MOUNT_POINT_PRIMARY and PAL_FS_MOUNT_POINT_SECONDARY.

Note: Do not add trailing / to the paths.

For a production device they should be set to partitions which are persistent between reboots and firmware updates. Your factory process must be aligned with this setting, it has to use same path.

The primary and secondary mount points may be the same (e.g. for single partition systems). Recommendation is to use the /mnt/config/ directory.

If the secondary mount point is different than the primary mount point, it will be used as backup configuration storage.

After starting Edge Core, you can start the protocol translator. It connects then to Edge Core:

Configuring the subdevice FOTA

To enable the subdevice FOTA, you need to build edge-core with the FOTA_ENABLE along with FIRMWARE_UPDATE cmake flag. You can also configure the download location of the firmware by explicitly defining the SUBDEVICE_FIRMWARE_DOWNLOAD_LOCATION flag. By default the firmware will be downloaded to the working directory. For example:

    cmake -D[MODE] -DFIRMWARE_UPDATE=ON -DFOTA_ENABLE=ON  -DSUBDEVICE_FIRMWARE_DOWNLOAD_LOCATION=\"your_download_location\" ..
    make

Protocol translator examples

Some protocol translator example implementations exist. These can be found from their own Github repository. The repository contains instructions on building and running the examples.

Makefile shortcuts for builds and running

At the repository root a Makefile is present with shortcuts to have specific build templates.

At first it is recommended to run the tests to see that the build environment is in correct shape: make -f Makefile.test run-tests. When environment is good to go the next step is to create a developer certificate build: make build-developer.

Default Makefile:

• make [build-developer|build-developer-debug|build-developer-with-coverage|build-byoc|build-factory] will build the project for the specified provisioning .
• make [run-edge-core|run-edge-core-valgrind|] runs the Edge Core. Pre-condition is one of the builds above.
• make [run-edge-core-resetting-storage] runs Edge Core resetting the storage i.e. it gives edge-core the --reset-storage parameter. Pre-condition is one of the builds above.

Test Makefile Makefile.test:

• make -f Makefile.test [build-test-byoc|build-test-devmode] builds and runs tests.
• make -f Makefile.test [run-tests|run-tests-with-valgrind] runs the Edge core tests without Valgrind or with Valgrind.
• make -f Makefile.test [run-coverage] builds, runs tests and collects coverage.

Running tests and generating and viewing test coverage report manually

The coverage report can be generated by issuing:

make -f Makefile.test run-coverage

To view the report:

firefox build/coverage.html/index.html

NOTE! If you have a snap-based Firefox in use, it will not have access rights to show local files anymore.

Running the tests with valgrind by issuing

make -f Makefile.test run-tests-with-valgrind

Debugging with gdb:

Make a debug build so that compiler optimizations are disabled to make debugging easier. The debug mode can be switched with CMake by giving the build type -DCMAKE_BUILD_TYPE=Debug.

mkdir build-test
cd build-test
cmake -DBUILD_TARGET=test -DCMAKE_BUILD_TYPE=Debug -D[FLAGS] ..
make
gdb ./bin/edge-core-test
gdb ./bin/pt-client-test

Generating Doxygen

make build-doc

This generates the Doxygen documentation under build-doc/doxygen folder. Run for example: firefox build-doc/doxygen/index.html & to view them.

NOTE! If you have a snap-based Firefox in use, it will not have access rights to show local files by default.

Troubleshooting

mbed-edge will not start due port being taken

$ bin/edge-core 
2023-12-11 11:42:06.302 tid:  20972 [ERR ][serv]: Couldn't bind to port 8080.
2023-12-11 11:42:06.302 tid:  20972 [ERR ][serv]: Cannot create http server to port 8080.
2023-12-11 11:42:06.302 tid:  20972 [ERR ][serv]: Could not create http server.

Someone else has taken port 8080. You can see who is taking the port with:

sudo lsof -i :8080 

Solutions:

• Remove that other program using that same port.
• Start mbed-edge to a different port than 8080 (`bin/mbed-edge --http-port ``).