Search code, repositories, users, issues, pull requests...
I'm writing a networking stack on a microcontroller. Not for production, or to make the fastest/smallest footprint/insert metric here, but just to get a deeper understanding about how things work all the way at the bottom, and hopefully to be able to make a video series out of the knowledge at some point in the future.
I left off having successfully sent a test ethernet packet (or more pedantically, a frame, as a few hackernews commenters pointed out!), by talking a simple SPI protocol to an W5100 ethernet ASIC, where the packet was placed into its internal buffer and commanded to be sent out over the physical lines. The end goal, of course, is to have an operating TCP/IP networking stack, and to be able to do fun things like host a webserver, and make HTTP requests.
But how do you get from sending the lowest level messages over a network, MAC address to MAC address, to things like hostnames, IP addresses, ports, and reliable network transmission? We're going to cover a little bit of that in this article - primarily how I was able to use DHCP to obtain an IP address from my home network, but also how the overall architecture of the firmware is laid out, and of course how I build some tooling to help debug the whole process.
