feat(relay): emit external address on reservation

protocols/relay/CHANGELOG.md

@@ -1,5 +1,9 @@
-## 0.17.0
 
+## 0.17.1 - unreleased
+- Emit an external address on making reservation.
+  See [PR 4809](https://github.com/libp2p/rust-lib2pp/pulls/4809).
+
+## 0.17.0
 - Don't close connections on protocol failures within the relay-server.
   To achieve this, error handling was restructured:
   - `libp2p::relay::outbound::stop::FatalUpgradeError` has been removed.

protocols/relay/src/priv_client.rs

@@ -33,6 +33,7 @@ use futures::future::{BoxFuture, FutureExt};
 use futures::io::{AsyncRead, AsyncWrite};
 use futures::ready;
 use futures::stream::StreamExt;
+use libp2p_core::multiaddr::Protocol;
 use libp2p_core::{Endpoint, Multiaddr};
 use libp2p_identity::PeerId;
 use libp2p_swarm::behaviour::{ConnectionClosed, ConnectionEstablished, FromSwarm};
@@ -79,6 +80,9 @@ pub struct Behaviour {
     /// connection.
     directly_connected_peers: HashMap<PeerId, Vec<ConnectionId>>,
 
+    /// Direct connection address
+    direct_connection_addrs: HashMap<ConnectionId, Multiaddr>,
+
     /// Queue of actions to return when polled.
     queued_actions: VecDeque<ToSwarm<Event, Either<handler::In, Void>>>,
 
@@ -92,6 +96,7 @@ pub fn new(local_peer_id: PeerId) -> (Transport, Behaviour) {
         local_peer_id,
         from_transport,
         directly_connected_peers: Default::default(),
+        direct_connection_addrs: Default::default(),
         queued_actions: Default::default(),
         pending_handler_commands: Default::default(),
     };
@@ -126,6 +131,7 @@ impl Behaviour {
                     unreachable!("`on_connection_closed` for unconnected peer.")
                 }
             };
+            self.direct_connection_addrs.remove(&connection_id);
         }
     }
 }
@@ -186,6 +192,10 @@ impl NetworkBehaviour for Behaviour {
                         .entry(peer_id)
                         .or_default()
                         .push(connection_id);
+
+                    let addr = endpoint.get_remote_address().clone();
+
+                    self.direct_connection_addrs.insert(connection_id, addr);
                 }
 
                 if let Some(event) = self.pending_handler_commands.remove(&connection_id) {
@@ -209,7 +219,7 @@ impl NetworkBehaviour for Behaviour {
     fn on_connection_handler_event(
         &mut self,
         event_source: PeerId,
-        _connection: ConnectionId,
+        connection: ConnectionId,
         handler_event: THandlerOutEvent<Self>,
     ) {
         let handler_event = match handler_event {
@@ -219,6 +229,17 @@ impl NetworkBehaviour for Behaviour {
 
         let event = match handler_event {
             handler::Event::ReservationReqAccepted { renewal, limit } => {
+                let addr = self
+                    .direct_connection_addrs
+                    .get(&connection)
+                    .cloned()
+                    .expect("Connection to be direct")
+                    .with(Protocol::P2pCircuit)
+                    .with(Protocol::P2p(self.local_peer_id));
+
+                self.queued_actions
+                    .push_back(ToSwarm::ExternalAddrConfirmed(addr));
+
                 Event::ReservationReqAccepted {
                     relay_peer_id: event_source,
                     renewal,
@@ -236,7 +257,7 @@ impl NetworkBehaviour for Behaviour {
             }
         };
 
-        self.queued_actions.push_back(ToSwarm::GenerateEvent(event))
+        self.queued_actions.push_back(ToSwarm::GenerateEvent(event));
     }
 
     fn poll(

protocols/relay/tests/lib.rs

@@ -169,6 +169,7 @@ fn new_reservation_to_same_relay_replaces_old() {
                         break;
                     }
                 }
+                SwarmEvent::ExternalAddrConfirmed { .. } => {}
                 SwarmEvent::Behaviour(ClientEvent::Ping(_)) => {}
                 e => panic!("{e:?}"),
             }
@@ -521,6 +522,7 @@ async fn wait_for_reservation(
 
     loop {
         match client.select_next_some().await {
+            SwarmEvent::ExternalAddrConfirmed { .. } => {}
             SwarmEvent::Behaviour(ClientEvent::Relay(
                 relay::client::Event::ReservationReqAccepted {
                     relay_peer_id: peer_id,