So the first step I would do to start on a TCP/IP stack would be "how to open a raw socket" (granted you have to know the magic phrase here). There's also tons of "how to implement TCP stack" articles (same for ethernet etc) that probably are good starting points if I didn't know that magic phrase. The other thing is to find people to talk to who know more than you to answer those questions.
Once you have that, you can setup a real TCP socket on one end and a raw socket client on the other & then the same thing in reverse. Then look up the TCP/IP framing on Wikipedia (+ read up on the broad overview of how TCP works and the various parts). Once you have the framing implemented, try implementing the basic sequence to establish a connection. Then keep noting what features a full TCP stack has, which are required, & which are missing from my implementation (that's when I'd start reaching for the standards that everyone references).
Of course, if you want to do something novel beyond just "hey I have confidence that I can implement such a stack myself" (e.g implementing something with certain performance characteristics) that requires a deeper understanding of how things work and a good filter on possible ideas & which ones are going to likely work out the best (that is gained through expertise, creativity & intelligence)
My favourite programming book is structured like this "elements of computer systems" also referred to as "from nand to Tetris"
After getting into university I decided to build an interpreter[0]. For someone who didn't even have the notion of a parser, it just felt like an unaproachable task. Even though, I sticked to it and the architecture became clear in time. That's another thing, even if you try to build something and miserably fail at it at each iteration, you still get better at it. The feeling of the task being too vast and daunting is just a feeling and knowing there's something on the other side makes it easier to power through it.
Hope to see your database on HN someday! :^)
As for db's/other interesting things, I haven't read them myself but this site seems solid https://build-your-own.org/. If anyone has any real experience with this site, I would love to hear it!
- Read the spec(s)
- Learn the OS APIs deeply
- Look at a bunch of real network data in e.g. Wireguard
I think you probably meant data in e.g. Wireshark?
But another good suggestion (or maybe what you meant) might be to look at 'real' (production) networking code in e.g. Wireguard, I imagine.