Relay circuit-v2 expiration

[mkuhn19]

Hi,

I am trying to develop a peer to peer application using rust and libp2p. I have nodes behind NAT and therefore need to use a mechanism such as relays to allow them to communicate.

I just read the relay circuit-v2 specs.
As far as I understood, when a node makes a reservation request, the relay responds with a HopMessage. The message should contains the reservation field with an expire field inside, as described there.

I have questions about this expire field :

1. I believe the node needs to make a new reservation request after expire time. Is that correct ?

2. How can I read the expire field ?
   Here is how I proceed :
   Firstly, the node makes a reservation request by listening on the relay address with the P2pCircuit protocol.

let relay_addr = Multiaddr::empty()
                .with(Protocol::Ip4(Ipv4Addr::new(127,0,0,1)))
                .with(Protocol::Tcp(RELAY_PORT))
                .with(Protocol::P2p(relay_peer_id()))
                .with(Protocol::P2pCircuit);
            self.swarm.listen_on(relay_addr)?;

The relay_addr looks like /ip4/192.168.1.19/tcp/62500/p2p/12D3KooWMAXwrRcBdK3hFECY7b69PVW5rfHRa2WQPmbmMezZnEVG/p2p-circuit/
(When one wants to connect to the node, it uses the relay_addr and adds p2p/<NODE_PEER_ID>.).

To handle the reservation request event, my code looks like this :

loop {
    event = self.swarm.select_next_some() => match event {
         SwarmEvent::Behaviour(ClientBehaviourEvent::Relay(relay::client::Event::ReservationReqAccepted { relay_peer_id, renewal, limit })) => {
                        // ....
                    }

    }
}

Shouldn't the expirefield be there ?
I think I misunderstood something here, can you help me ?

Thank you !

[thomaseizinger]

The reservation will be automatically renewed in the background:

rust-libp2p/protocols/relay/src/priv_client/handler.rs

Lines 661 to 667 in c86b665

	Poll::Ready(()) => (
	Reservation::Renewing { pending_msgs },
	Poll::Ready(Some(SubstreamProtocol::new(
	outbound_hop::Upgrade::Reserve,
	OutboundOpenInfo::Reserve { to_listener },
	))),
	),

[mkuhn19]

Thank you for such a fast answer 😄
Have a nice day !