How to organize packet capture?

Question

go

Good time.
As a learning material, I decided to write a script that intercepts client-server packets.
As a client, there can be: an online game, a browser, an antivirus, etc.
The purpose is this:
The script receives the received packet from the server, processes it and decides whether to transfer it to the client or not.
What materials and books would you recommend for studying this topic?

Answer 1

Write a script that calls the sniffer from the Linux command line, and then deal with the packages. This is analysis. So you can see the traffic.
You can manage packets only at the firewall level. Either you need to modify the network device driver or the firewall. Intervention at this level in the operation of the network requires more work than writing a script.

Answer 2

If there are no issues with the network stack, I would probably recommend reading about OS kernel devices (if we are talking about Linux / BSD). For Windows, this will most likely be implemented at the driver level (judging by antiviruses, unfortunately I won’t say more about Windows).
You can also read source codes or books about firewalls and books on how they work (iptables, ipfw, pf, etc.), again, if we talk about * nix. Among other things, they have modes that allow you to send packets to third-party applications for analysis.
You can also read about the Proxy / Socks device and the network as a whole, there is a lot of literature, incl. in Russian, but this is rather a bit beyond the scope of the original topic of the question.
If you decide what exactly you want to read about, then it will be much easier to recommend something specific. Separately, you will hardly find books or even articles "how to transfer a package to an external application for analysis"; such a book/article will be limited to a few lines (in relation to *nix's, I can't say for Windows).