my-tap-journey.markdown (#33)

Author: adam-3bian

_posts/2025-03-14-my-tap-journey.markdown

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+---
+layout: post
+title:  "My TAP Journey"
+date:   2025-03-14
+categories: tap sonata cheriot-rtos
+author: Adam Finney
+---
+
+Over the past few months, I have had the opportunity to work with CHERIoT and Sonata in ways that have really pushed me as a developer.
+When I started this project, I knew that CHERI's capability based memory model was something special, but I did not fully appreciate how much it would change the way I think about secure embedded systems.
+This has been more than just a technical challenge. It has been a genuine learning experience that has reshaped how I approach programming, security, and system design.
+
+# Discovering CHERIoT and Sonata
+
+When I first started working with CHERIoT, I knew it was designed to tackle one of the biggest problems in embedded development: security, buffer overflows, memory corruption, and other memory related issues have plagued embedded systems for decades.
+CHERIoT's capability based memory model offers a fundamentally different way of handling these problems at the hardware level.
+Instead of patching the symptoms, it removes the underlying vulnerabilities.
+
+Sonata, as the development platform for CHERIoT, gave me the chance to put these ideas into practice.
+It was a bit daunting at first. Figuring out how to structure code within that framework required a real shift in mindset.
+But once it started to click, I began to see how powerful it could be.
+Instead of constantly worrying about memory safety and unexpected crashes,
+I could focus more on building functionality, knowing that the hardware was helping to protect me from some of the most common programming mistakes.
+
+# Pushing Through Challenges
+
+There were definitely some challenging moments along the way. Early on, I tried to implement lwIP for networking, but it became clear that it was not the right fit.
+After seeing the [Hugh the Lightbulb](https://github.com/cheriot-Platform/cheriot-demos) demo, I switched to FreeRTOS plus TCP, and that turned out to be the right move.
+FreeRTOS plus TCP integrated much more smoothly with CHERIoT.
+
+Networking was a big focus for me.
+I have been working on finalising the IPv6 and UDP stack and preparing it for open source release.
+The packet sniffing and IPv6 proof of concept has been open source for a while now, but I realised it was using more power than it should because the filters were completely pass-through.
+Fixing that turned out to be more complicated than I expected.
+
+IPv6 and DTLS add an extra layer of complexity that required more than just tweaking the code.
+This was solved with the help of the community with compiler optimisations and the integration of HyperRAM.
+At the time of writing, the stack is in the shake down phase.
+That frustrating but exciting period where you know you are close to the finish line, but the last ten percent of the work feels like half the effort.
+
+# Shifting My Approach to Code
+
+One of the biggest changes for me has been how I now think about code structure.
+Before CHERIoT, I would organise code by function, grouping similar tasks together to keep things tidy and efficient.
+But CHERIoT's memory model encourages a different way of thinking.
+
+I started organising code by safety boundaries rather than function.
+I separated input and output from parsing and business logic, setting up compartments where failures in one area could not compromise the whole system.
+It required more upfront design work, but the payoff was huge.
+Debugging became easier, failures were contained, and the overall stability of the system improved significantly.
+
+Compartmentalisation has changed the way I write code, not just on CHERIoT but across other projects as well.
+It makes you more thoughtful about how data flows through a system and where the vulnerabilities might be hiding.
+
+# What I Have Learned
+
+I think the biggest lesson I have taken away from this experience is that the hardest problems often need a completely new way of thinking.
+Trying to fix memory safety at the software level will only take you so far.
+You need to solve it at the hardware level, which is exactly what CHERIoT does.
+
+Working with a strong community makes a huge difference.
+Being able to ask questions, share ideas, and learn from others' experiences has made the process so much smoother.
+The idea of combining a top down strategy with a bottom up, grassroots approach feels like the right way to drive adoption and make CHERIoT and Sonata a success.
+
+