Add port scan

[bdougherty]

Not sure what Apple used for doing port scanning.

[jeff-h]

Would it have been lsof perhaps?

[luckydonald]

According to Wikipedia's old page,

Network Utility uses the tools supplied in the unix directories for most of its functions, however for the port scan it uses a unix executable in its resources folder, stroke, found at Network Utility.app/Contents/Resources/stroke.

[jeff-h]

Aha, nice find! Do you think Stroke was an internal tool developed by Apple? I can't find any reference to it outside of its use inside Network Utility.

More broadly, I find it extraordinary that macOS/Unix seems to have to check each port in order to see if it's in use. I'd have thought there would be a central registry or something tracking which ports are available and which are not, and such a query would be an almost instantaneous system call.

[luckydonald]

The port scan is of other hosts, so it needs some kind of bruteforce there.

I wonder if one could decompile the old binary to figure out what's it doing on its core.

[jeff-h]

The port scan is of other hosts, so it needs some kind of bruteforce there.

Ha, of course, sorry! I'm too fixated on my own particular use-case (scanning localhost).

Presumably bundling an existing binary (perhaps nmap?) would be more efficient than writing a new one?