transport: Failed addresses are not reported back on a successful connection

[lexnv]

The TCP transport layer takes 8 addresses to dial. If 1 is successful and 7 are unreachable, the 7 errors are not propagated back to the transport manager.

The downstream effect is that the address scores of the 7 unreachable addresses are not updated. This then leaves the 7 known unreachable addresses to be considered as reachable to the next "Dial attempt".

In passeo, this has been observed on a validator wrongly configured with 31 addresses:

• only one of the 31 addresses are reachable
• if the good address is picked, the rest 7 that would fail are ignored

The TransportEvent::ConnectionOpened needs to take into account the errors generated during dialing:

litep2p/src/transport/tcp/mod.rs

Lines 586 to 608 in 7e048bf

	RawConnectionResult::Connected { negotiated, errors } => {
	let Some(handle) = self.cancel_futures.remove(&negotiated.connection_id())
	else {
	tracing::warn!(
	target: LOG_TARGET,
	connection_id = ?negotiated.connection_id(),
	address = ?negotiated.endpoint().address(),
	?errors,
	"raw connection without a cancel handle",
	);
	continue;
	};
	if !handle.is_aborted() {
	let connection_id = negotiated.connection_id();
	let address = negotiated.endpoint().address().clone();
	self.opened.insert(connection_id, negotiated);
	return Poll::Ready(Some(TransportEvent::ConnectionOpened {
	connection_id,
	address,
	}));

Part of:

• [ElasticScaling] Enable ElasticScaling on AHKusama and AHPolkadot polkadot-sdk#10425