Experimental dht client

[aschmahmann]

This feature enables an option for an experimental DHT client that makes a few key optimizations over the standard client.

1. It periodically crawls the network to find all the peers and then finds the closest peers to the target in Kademlia space based on the local list of peers
2. It does not wait on all peers from a given query to return, but instead tries to guess when we'll be done hearing from peers and instead be waiting on timeouts.
   • The current metric is to wait for some percentage (30%) of the closest bucket-size (i.e. 20) peers to return and then wait for some dead time (a few hundred ms) where no new responses come in

Depends on:

• experimental dht client config go-ipfs-config#125
• Crawler based DHT client libp2p/go-libp2p-kad-dht#709

A couple quirks about the current state of this PR and the client:

• I've manually set the experimental option to always on for debugging purposes (will turn off before merge)
  • turned off
• The DHT client crawls for updates once an hour and takes about 10 minutes to complete in my tests on the live network
  • This means the node's DHT is unusable for the first 10 minutes of operation
  • This means many of the DHT tests will fail since the node will either not have an updated view of the network or will simply have an empty routing table
• Given the utility of a faster DHT client I'm hoping that an experimental client that's much much faster and that the community can hammer on will be appreciated while we work on improving the client to handle more of the edge cases

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This PR also includes an experimental provider system which utilizes the experimental dht client and is bundled with it - the originating PR was #8070

[alanshaw]

What are wanserver/lanserver and are they new? Can the description explain 🙏

[alanshaw]

Add a note that if the daemon is running it must be restarted?