Make gossipsub actually listen on 0.0.0.0

[Frederik-Baetens]

swarm.listen_on("/ip4/0.0.0.0/tcp/0".parse()?).unwrap(); makes my gossipsub swarm randomly choose to listen on 127.0.0.1 or on my internal ip, but apparently not both. The following code also only returns 127.0.0.1 or my LAN ip:

            for addr in swarm.listeners() {
                println!("Listening on {:?}", addr);
                listening = true;
            }

This makes it so that I can't use 127.0.0.1 to connect to libp2p when the swarm decided to only listen on my LAN ip.

With other services, listening on 0.0.0.0, enables listening on both 127.0.0.1 & the LAN/WAN ip. How can I achieve this behavior with libp2p?

[mxinden]

I am not sure I follow, nor can I reproduce the issue. Mind elaborating further / adding more details?

Note that libp2p-gossipsub as a NetworkBehaviour is not aware of the transport protocol, nor which addresses to listen on.

[Frederik-Baetens]

I was mistaken about not being able to connect to 127.0.0.1 sometimes, I must have another bug somewhere in my larger project then. However it is annoying that swarm.listeners() randomly switches between returning 127.0.0.1 and my lan ip.

Example here: https://github.com/Frederik-Baetens/libp2p-tokiochat

It's adapted from the examples, and just uses gossipsub without mdns.

You can run it with cargo run, and connect a second node with cargo run -- /ip4/127.0.0.1/tcp/44901 (replace the multiaddr with the one the first node prints.

[rkuhn]

If you check right after calling .listen_on then you’ll first get one and then the other address, in no particular order. You can observe the Swarm’s events to get notified of all addresses as they are discovered — unfortunately there is no signal from which you can deduce that “now I have all addresses”, because new listen addresses will continue to be discovered as your device’s network environment changes.

[mxinden]

To add to what @rkuhn said above, I recommend continuously reporting the listen addresses, e.g. as done here:

rust-libp2p/examples/ping.rs

Lines 77 to 79 in e19391e

	loop {
	match swarm.select_next_some().await {
	SwarmEvent::NewListenAddr { address, .. } => println!("Listening on {:?}", address),