feat: prune old, inactive paths

[ramfox]

Description

Prune paths that are not actively being used, about to be dialed, or old.

Notes and Questions

The logic of gathering all of the relevant information is in the fn prune_ip_paths function, not in the self.prune_ip_paths method on EndpointActorState. Separating these out made it easier to test.

Used AI to help write tests & reduce allocations when working through the paths.

keep_path is where we can play around in the future with what exactly we want to keep, based on the PathState, if we want to get more strict or particular as we learn more.

Right now we:

• keep paths that are open
• keep paths that are waiting to be opened
• keep paths that have not ever been pinged
• have at least one source that was given to us less that 2 mins ago

This means:

• we only prune paths if they are inactive, have previously been pinged (so we attempted to hole punch them) and have not been given to us or connected in over 2 mins

Also, we only do prune this if there are more that 20 inactive paths open.

I've added prune_ip_paths anytime we insert a path to the EndpointActorState::paths. However, there are two places I did not add this check, that maybe I should. But my brain is a bit fuzzy right now, so I will do another review about where these checks should go.

That being said, I think this is ready for initial review, at least.

[github-actions]

Documentation for this PR has been generated and is available at: https://n0-computer.github.io/iroh/pr/3666/docs/iroh/

Last updated: 2025-11-17T19:10:02Z