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Ask HN: Looking for tool/language to describe data/packet structures

by tinktank on 2/11/23, 4:21 PM with 4 comments

I'm looking or a tool that will allow me to textually describe data/packet structures for the purposes of creating visual representations of the structures. If it's capable of expressing constraints or assertations that would be even better. Examples of constraints/assertions:

- This field should always be n bits into the start of the structure - The size of this structure shouldn't exceed B bits - This field should never be less than s bits

The capability to output image formats directly is preferred, but I'm not opposed to having to script it and tie it up to an image generation library.

I'd prefer a CLI tool so the flow is all on my local machine.

by jiveturkey on 2/11/23, 4:46 PM
http://interactive.blockdiag.com/packetdiag/
https://github.com/arnoldrobbins/dformat
by codegladiator on 2/11/23, 5:34 PM
Checkout kaitai
https://doc.kaitai.io/
Its not for generating visual structure, but just defining the structure with the constraints like you mentioned
by cookiengineer on 2/12/23, 3:53 AM
In the network security space there's pcap-ng and yara that's pretty common as a network filter ruleset generator.
There's also a lof of visual IDEs for the creation of yara rules, which tend to break it down in a flow-based graph so that the logical conditions are easier to understand.
Yara is pretty flexible in what you can do with it, a lot of anti malware tools use it for detection, as well as more modern hex editors like ImHex.
Older-generation tech used to use snort and its rule format, especially in the Enterprise space it's (sadly) still common.
by renewiltord on 2/11/23, 7:27 PM
Protocol exists but is unmaintained (I think) https://www.luismg.com/protocol/
Wavedrom and ascii wave is for tming https://github.com/Wren6991/asciiwave