Networking Primitives to get ready for Sentry Nodes

[rphmeier]

Sentry nodes are special nodes set up by a validator operator that are intended to be the points-of-contact for the validator node, which is shielded from public connections.

Typically, sentry nodes will function as normal nodes. But for consensus networking in particular, they will have to behave as though they are the validator node. That means that it needs to become aware of what knowledge the validator node has.

This will typically be handled on the level of particular networking protocols (knowing how to proxy certain requests to the underlying validator).

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Basics

What needs to be made available to the networking protocol:

• Whether the local node has sentry nodes and what their PeerIds are.
• Whether the local node is a sentry node and what its PeerId is.

This information needs to be made available to the core-level networking, any NetworkSpecialization and any consensus_gossip::GossipValidator

Then we'll also need CLI parameters for configuring and setting up sentry nodes.

[rphmeier]

cc @twittner : do you have some input on how best to integrate into the substrate networking to attach info onto PeerIds when connecting?

[twittner]

• Whether the local node is a sentry node and what its PeerId is.

What the PeerId of its validator node is?

do you have some input on how best to integrate into the substrate networking to attach info onto PeerIds when connecting?

I am not sure what you mean. I think information about PeerIds would go into network::config::NetworkConfiguration.

[rphmeier]

What the PeerId of its validator node is?

yes, sorry.

[tomaka]

Done as part of #5520 #5665