AWS IoT Device Defender Library

The Device Defender library enables you to send device metrics to the AWS IoT Device Defender Service. This library also supports custom metrics, a feature that helps you monitor operational health metrics that are unique to your fleet or use case. For example, you can define a new metric to monitor the memory usage or CPU usage on your devices. This library has no dependencies on any additional libraries other than the standard C library, and therefore, can be used with any MQTT client library. This library is distributed under the MIT Open Source License.

This library has gone through code quality checks including verification that no function has a GNU Complexity score over 8, and checks against deviations from mandatory rules in the MISRA coding standard. Deviations from the MISRA C:2012 guidelines are documented under MISRA Deviations. This library has also undergone static code analysis using Coverity static analysis, and validation of memory safety through the CBMC automated reasoning tool.

See memory requirements for this library here.

AWS IoT Device Defender v1.3.0 source code is part of the FreeRTOS 202210.00 LTS release.

AWS IoT Device Defender v1.1.0 source code is part of the FreeRTOS 202012.01 LTS release.

AWS IoT Device Defender Client Config File

The AWS IoT Device Defender Client Library exposes build configuration macros that are required for building the library. A list of all the configurations and their default values are defined in defender_config_defaults.h. To provide custom values for the configuration macros, a config file named defender_config.h can be provided by the application to the library.

By default, a defender_config.h config file is required to build the library. To disable this requirement and build the library with default configuration values, provide DEFENDER_DO_NOT_USE_CUSTOM_CONFIG as a compile time preprocessor macro.

Thus, the Device Defender client library can be built by either:

• Defining a defender_config.h file in the application, and adding it to the include directories list of the library.

OR

• Defining the DEFENDER_DO_NOT_USE_CUSTOM_CONFIG preprocessor macro for the library build.

Building the Library

The defenderFilePaths.cmake file contains the information of all source files and the header include paths required to build the Device Defender client library.

As mentioned in the previous section, either a custom config file (i.e. defender_config.h) or DEFENDER_DO_NOT_USE_CUSTOM_CONFIG macro needs to be provided to build the Device Defender client library.

For a CMake example of building the Device Defender client library with the defenderFilePaths.cmake file, refer to the coverity_analysis library target in test/CMakeLists.txt file.

Building Unit Tests

Platform Prerequisites

• For running unit tests:
  • C90 compiler like gcc.
  • CMake 3.13.0 or later.
  • Ruby 2.0.0 or later is additionally required for the CMock test framework (that we use).
• For running the coverage target, gcov and lcov are additionally required.

Steps to build Unit Tests

1. Go to the root directory of this repository.

2. Run the cmake command: cmake -S test -B build -DBUILD_CLONE_SUBMODULES=ON.

3. Run this command to build the library and unit tests: make -C build all.

4. The generated test executables will be present in build/bin/tests folder.

5. Run cd build && ctest to execute all tests and view the test run summary.

CBMC

To learn more about CBMC and proofs specifically, review the training material here.

The test/cbmc/proofs directory contains CBMC proofs.

In order to run these proofs you will need to install CBMC and other tools by following the instructions here.

Reference examples

The AWS IoT Embedded C-SDK repository contains a demo showing the use of AWS IoT Device Defender Client Library here on a POSIX platform.

Documentation

Existing documentation

For pre-generated documentation, please see the documentation linked in the locations below:

Location
AWS IoT Device SDK for Embedded C
FreeRTOS.org

Note that the latest included version of the AWS IoT Device Defender library may differ across repositories.

Generating documentation

The Doxygen references were created using Doxygen version 1.9.2. To generate the Doxygen pages, please run the following command from the root of this repository:

doxygen docs/doxygen/config.doxyfile

Contributing

See CONTRIBUTING.md for information on contributing.