Investigate TODOs in Network Vat

[iomekam]

Describe the bug

We've been doing a bunch of work to make the network and IBC vats durable. While doing that work, we've run into a few concerning comments that may need to be addressed before the network vat is ready for production

To Reproduce

agoric-sdk/packages/network/src/network.js

Lines 207 to 213 in a253f74

	/**
	* Currently must be a single listenHandler. TODO: Do something sensible with
	* multiple handlers?
	*
	* @type {MapStore<Endpoint, [Port, ListenHandler]>}
	*/
	const listening = makeScalarMapStore('localAddr');

agoric-sdk/packages/network/src/network.js

Line 270 in a253f74

// TODO: Check that the listener defines onAccept.

agoric-sdk/packages/network/src/network.js

Lines 207 to 213 in a253f74

	/**
	* Currently must be a single listenHandler. TODO: Do something sensible with
	* multiple handlers?
	*
	* @type {MapStore<Endpoint, [Port, ListenHandler]>}
	*/
	const listening = makeScalarMapStore('localAddr');

agoric-sdk/packages/network/src/network.js

Lines 531 to 579 in a253f74

	return Far('ProtocolHandler', {
	// eslint-disable-next-line no-empty-function
	async onCreate(_impl, _protocolHandler) {
	// TODO
	},
	async generatePortID(_protocolHandler) {
	return makePortID();
	},
	async onBind(_port, _localAddr, _protocolHandler) {
	// TODO: Maybe handle a bind?
	},
	async onConnect(_port, localAddr, remoteAddr, _chandler, protocolHandler) {
	const [lport, lhandler] = listeners.get(remoteAddr);
	const rchandler =
	/** @type {ConnectionHandler} */
	(await E(lhandler).onAccept(lport, remoteAddr, localAddr, lhandler));
	// console.log(`rchandler is`, rchandler);
	const remoteInstance = await E(protocolHandler)
	.onInstantiate(lport, remoteAddr, localAddr, protocolHandler)
	.catch(rethrowUnlessMissing);
	return {
	remoteInstance,
	handler: rchandler,
	};
	},
	onInstantiate,
	async onListen(port, localAddr, listenHandler, _protocolHandler) {
	// TODO: Implement other listener replacement policies.
	if (listeners.has(localAddr)) {
	const lhandler = listeners.get(localAddr)[1];
	if (lhandler !== listenHandler) {
	// Last-one-wins.
	listeners.set(localAddr, [port, listenHandler]);
	}
	} else {
	listeners.init(localAddr, [port, listenHandler]);
	}
	},
	async onListenRemove(port, localAddr, listenHandler, _protocolHandler) {
	const [lport, lhandler] = listeners.get(localAddr);
	lport === port || Fail`Port does not match listener on ${localAddr}`;
	lhandler === listenHandler ||
	Fail`Listen handler does not match listener on ${localAddr}`;
	listeners.delete(localAddr);
	},
	async onRevoke(_port, _localAddr, _protocolHandler) {
	// TODO: maybe clean up?
	},
	});

Expected behavior

These TODOs should be investigated to ensure that there isn't missing functionality/work that needs to be done. If we can launch with them in place, they should be replaced with issues tracking each item.

Platform Environment

all platforms since mainnet1B launch.

[dckc]

note also some commented-out code #8721 (comment)

[dckc]

@michaelfig The impact of these isn't clear to me. I'm going to have to interview you or @warner or somebody...

The loopback protocol ( prepareLoopbackProtocolHandler ) is mostly for testing, but it will be part of the network vat in production, right?
The onCreate body is marked TODO. We don't seem to be suffering from that.
Do I understand correctly that onCreate is an opportunity to do suff, but there is no obligation?

or is loopback used more than that?