fix(ext/node): enable reuseport for net Socket on macOS

[littledivy]

• Enables SO_REUSEPORT on macOS
• All Node net.Socket TCP sockets are set to SO_REUSEPORT.

Fixes #20618
Fixes #18301

Modules working: npm:http-server, npm:portfinder and Vuepress dev server

[lucacasonato]

What does SO_REUSEPORT do on macOS? When I originally implemented this for Linux, I didn't do macOS because there was no reason for anyone to use it (because it behaves different on macOS - it steals rather than balances). What do these packages use it for?

[bartlomieju]

https://github.com/denoland/deno/pull/20869/files#r1352540623

[lucacasonato]

Also I think you don't want SO_REUSEPORT, but SO_REUSEADDR (and enable that by default everywhere). libuv does not enable (or let you enable) SO_REUSEPORT on TCP sockets anywhere (including macOS). It does enable SO_REUSEADDR on all Unix.

[littledivy]

@lucacasonato is right. libuv does not set SO_REUSEPORT for TCP (UDP only on BSDs)

It looks like portfinder is also flaky/broken in Node -

• Wait until server is closed before invoking callback http-party/node-portfinder#149
• Wait until server is closed before invoking callback. http-party/node-portfinder#105 (Fix was rejected because they don't want to modify the library)

@bartlomieju How should we proceed?

[bartlomieju]

@littledivy I'm not sure yet - but given this package is popular we need to come up with some solution that will work in most cases (compared to always crashing right now).

[littledivy]

Closing because stale.