transport-manager/part 2: Unknown secondary connections for multiple dials

[lexnv]

Part two of: #172

Detected during triaging of: paritytech/polkadot-sdk#5609

    "2024-09-07 21:43:54.157  WARN tokio-runtime-worker litep2p::transport-manager: unknown connection opened as secondary connection, discarding peer=PeerId(\"12D3KooWGTnNXimfyieaZAeyRDvZLQpFF7Nr9a8bS3oN4yMPQExZ\") connection_id=ConnectionId(2347697) address=\"/ip4/212.224.112.221/tcp/49054/ws/p2p/12D3KooWGTnNXimfyieaZAeyRDvZLQpFF7Nr9a8bS3oN4yMPQExZ\" dial_record=AddressRecord { score: 100, address: \"/ip4/212.224.112.221/tcp/30333/p2p/12D3KooWGTnNXimfyieaZAeyRDvZLQpFF7Nr9a8bS3oN4yMPQExZ\", connection_id: Some(ConnectionId(2347695)) }",
    "2024-09-07 21:43:54.243  WARN tokio-runtime-worker litep2p::transport-manager: unknown connection opened as secondary connection, discarding peer=PeerId(\"12D3KooWGTnNXimfyieaZAeyRDvZLQpFF7Nr9a8bS3oN4yMPQExZ\") connection_id=ConnectionId(2347700) address=\"/ip4/212.224.112.221/tcp/49068/ws/p2p/12D3KooWGTnNXimfyieaZAeyRDvZLQpFF7Nr9a8bS3oN4yMPQExZ\" dial_record=AddressRecord { score: 100, address: \"/ip4/212.224.112.221/tcp/30333/p2p/12D3KooWGTnNXimfyieaZAeyRDvZLQpFF7Nr9a8bS3oN4yMPQExZ\", connection_id: Some(ConnectionId(2347695)) }",
    "2024-09-07 21:43:54.309  WARN tokio-runtime-worker litep2p::transport-manager: unknown connection opened as secondary connection, discarding peer=PeerId(\"12D3KooWGTnNXimfyieaZAeyRDvZLQpFF7Nr9a8bS3oN4yMPQExZ\") connection_id=ConnectionId(2347701) address=\"/ip4/212.224.112.221/tcp/49072/ws/p2p/12D3KooWGTnNXimfyieaZAeyRDvZLQpFF7Nr9a8bS3oN4yMPQExZ\" dial_record=AddressRecord { score: 100, address: \"/ip4/212.224.112.221/tcp/30333/p2p/12D3KooWGTnNXimfyieaZAeyRDvZLQpFF7Nr9a8bS3oN4yMPQExZ\", connection_id: Some(ConnectionId(2347695)) }",
    "2024-09-07 21:43:54.335  WARN tokio-runtime-worker litep2p::transport-manager: unknown connection opened as secondary connection, discarding peer=PeerId(\"12D3KooWGTnNXimfyieaZAeyRDvZLQpFF7Nr9a8bS3oN4yMPQExZ\") connection_id=ConnectionId(2347704) address=\"/ip4/212.224.112.221/tcp/49076/ws/p2p/12D3KooWGTnNXimfyieaZAeyRDvZLQpFF7Nr9a8bS3oN4yMPQExZ\" dial_record=AddressRecord { score: 100, address: \"/ip4/212.224.112.221/tcp/30333/p2p/12D3KooWGTnNXimfyieaZAeyRDvZLQpFF7Nr9a8bS3oN4yMPQExZ\", connection_id: Some(ConnectionId(2347695)) }",
    "2024-09-07 21:43:54.449  WARN tokio-runtime-worker litep2p::transport-manager: unknown connection opened as secondary connection, discarding peer=PeerId(\"12D3KooWGTnNXimfyieaZAeyRDvZLQpFF7Nr9a8bS3oN4yMPQExZ\") connection_id=ConnectionId(2347706) address=\"/ip4/212.224.112.221/tcp/49078/ws/p2p/12D3KooWGTnNXimfyieaZAeyRDvZLQpFF7Nr9a8bS3oN4yMPQExZ\" dial_record=AddressRecord { score: 100, address: \"/ip4/212.224.112.221/tcp/30333/p2p/12D3KooWGTnNXimfyieaZAeyRDvZLQpFF7Nr9a8bS3oN4yMPQExZ\", connection_id: Some(ConnectionId(2347695)) }",

When we dial multiple addresses of the same peer, we set the same connection ID for all addresses.
The first successful connection is kept around, while the other pending connections are canceled.

Some thoughts and possible root causes:

• I suspect there might be a race between canceling dials and when dials are reported as successful, with the side effect of generating multiple warnings, of similar addresses with the same connection id. All warnings share the same ConnectionId(2347695).
• There's also a change that we don't track canceled dials properly (I remember we did some changes around those here: Fix TCP, WebSocket, QUIC leaking connection IDs in reject() #198)

[lexnv]

The pending incoming connections are only going through the filter of the connection limits at the moment:

litep2p/src/transport/manager/mod.rs

Lines 1749 to 1760 in a68b713

	if self.on_pending_incoming_connection().is_ok() {
	tracing::trace!(
	target: LOG_TARGET,
	?connection_id,
	"accept pending incoming connection",
	);
	let _ = self
	.transports
	.get_mut(&transport)
	.expect("transport to exist")
	.accept_pending(connection_id);

We can improve this by rejecting incoming connections for peers with a primary and secondary connections.