amos loves to tinker

When I launched my Patreon, I vowed to explain how computers work. But in 2019, computers rarely work in isolation. So let’s take the time to write a few articles about how computers talk to each other.

The history of network protocols and standards is long and...

So, how does ping.exe actually send a ping? It seems unrealistic that ping.exe itself implements all the protocols involved in sending a ping. So it must be calling some sort of library. Also, since it ends up talking to the outside world via a NIC (network interface...

It’s time to make sup, our own take on ping, use the Win32 APIs to send an ICMP echo. Earlier we discovered that Windows’s ping.exe used IcmpSendEcho2Ex. But for our purposes, the simpler IcmpSendEcho will do just fine.

As we mentioned earlier, it’s provided...

It’s refactor time!

Our complete program is now about a hundred lines, counting blank lines (see the end of part 3 for a complete listing).

While this is pretty good for a zero-dependency project (save for pretty-hex), we can do better.

First off, concerns are mixed...

We’ve just spent a lot of time abstracting over LoadLibrary, but we still have all the gory details of the Win32 ICMP API straight in our main.rs file! That won’t do.

This time will be much quicker, since we already learned about carefully designing an API, hiding...

Our ping API is simple, but it’s also very limited:

pub fn ping(dest: ipv4::Addr) -> Result<(), String>

// called as:
ping(ipv4::Addr([8, 8, 8, 8])).unwrap();

It doesn’t allow specifying the TTL (time to live) of packets, it doesn’t allow...

Let’s set aside our sup project for a while.

Don’t get me wrong - it’s a perfectly fine project, and, were we simply rewriting “ping” for Windows in Rust, we could (almost) stop there.

We’re currently using the operating system’s...

Okay, I lied.

I’m deciding - right this instant - that using wmic is cheating too. Oh, it was fair game when we were learning about Windows, but we’re past that now.

We know there’s IPv4 routing tables, and we know network interfaces have indices (yes, they...

Now that we’ve found the best way to find the “default network interface”… what can we do with that interface?

Well, listen for network traffic of course!

use rawsock::open_best_library;
use std::time::Instant;

fn main() -> Result<(), Error>...