There’s GNAT.Sockets and AdaSockets by Samuel Tardieu. Both implement TCP stream sockets and UDP datagram sockets, which probably covers 99% of use cases people have.
Now, imagine I want to bypass the transport layer and send a handcrafted package to a raw socket. I guess I need to directly bind to the system call, socket(AF_INET, SOCK_RAW, ...) or socket(AF_PACKET, SOCK_RAW, ...)? Similar to the bindings that Verisimilitude wrote for his UDP library, I guess?
What’s a good guide to start looking into calling C system functions?
Does the question even make sense?
Background: I came across a coding challenge to build a port scanner and for some reason thought it sounds intriguing. Suddenly I find myself in this rabbit hole of network programming. I’m completely new to it, as well as to low-level programming. So consider me a noob just starting to explore this territory…
What’s a good guide to start looking into calling C system functions?
I don’t remember finding one when I wrote Trendy Terminal, looks like AdaCore docs now have something - interfacing with c. It’s actually super well defined and supported by the language, and super easy, the big problem I ran into was dealing with all of the macros people like to use.
I poked around what’s on Alire to find some other libraries to look at, there’s a code search tool you can use to look for code across Alire. The big shenanigans I ran into was dealing with conditional compilation across platforms and getting gprbuild to deal with that.
I intend to write something using the so-called raw sockets, and it’s such a mess of C language text-replacement nonsense that I was just going to write a C language program for the very simple task I had in mind.
Read the documentation about the standard Interfaces.C package and its children. The number one pain in the ass is going to be binding things defined with text-replacement macros, and hunting down which types things use to get a definition not already handled by Interfaces.C.
Lastly, I’d appreciate being referred to as a man. I hate the singular they.
When binding to C programs that use a lot of macros, I’ve found that it’s easier to write a small wrapper in C that you call from Ada. This way you have control over which types and constants need to be defined in Ada.
Will do. My naive view was that it’s enough to use socket() and sendto() (passing the raw bytes of an assembled packet), but I guess the devil‘s in the detail - and I have no clue yet how to intercept the response.
(P.S. Changed „their“ to „his“; no offense meant. Just wasn’t sure.)
If you are new to network programming then Protohackers is a gentler introduction to the topic via programming challenges since it stays at the application layer.
I am making my way through protohackers in Ada and enjoying it since it involves a bit of tasks, timing, selectors and even some business logic.
