[identify] Add configurable automatic push on listen addr changes. (#2004)

* Add configurable automatic push of listen addr changes.

* Update changelog and cleanup.

protocols/identify/CHANGELOG.md

@@ -1,5 +1,9 @@
 # 0.29.0 [unreleased]
 
+- Add support for configurable automatic push to connected peers
+  on listen addr changes. Disabled by default.
+  [PR 2004](https://github.com/libp2p/rust-libp2p/pull/2004)
+
 - Implement the `/ipfs/id/push/1.0.0` protocol.
   cf. https://github.com/libp2p/specs/tree/master/identify#identifypush
   [PR 1999](https://github.com/libp2p/rust-libp2p/pull/1999)

protocols/identify/src/identify.rs

@@ -107,6 +107,16 @@ pub struct IdentifyConfig {
     ///
     /// Defaults to 5 minutes.
     pub interval: Duration,
+
+    /// Whether new or expired listen addresses of the local node should
+    /// trigger an active push of an identify message to all connected peers.
+    ///
+    /// Enabling this option can result in connected peers being informed
+    /// earlier about new or expired listen addresses of the local node,
+    /// i.e. before the next periodic identify request with each peer.
+    ///
+    /// Disabled by default.
+    pub push_listen_addr_updates: bool,
 }
 
 impl IdentifyConfig {
@@ -119,6 +129,7 @@ impl IdentifyConfig {
             local_public_key,
             initial_delay: Duration::from_millis(500),
             interval: Duration::from_secs(5 * 60),
+            push_listen_addr_updates: false,
         }
     }
 
@@ -141,6 +152,14 @@ impl IdentifyConfig {
         self.interval = d;
         self
     }
+
+    /// Configures whether new or expired listen addresses of the local
+    /// node should trigger an active push of an identify message to all
+    /// connected peers.
+    pub fn with_push_listen_addr_updates(mut self, b: bool) -> Self {
+        self.push_listen_addr_updates = b;
+        self
+    }
 }
 
 impl Identify {
@@ -194,7 +213,7 @@ impl NetworkBehaviour for Identify {
             ConnectedPoint::Listener { send_back_addr, .. } => send_back_addr.clone(),
         };
 
-        self.connected.entry(*peer_id).or_default().insert(*conn, addr.clone());
+        self.connected.entry(*peer_id).or_default().insert(*conn, addr);
     }
 
     fn inject_connection_closed(&mut self, peer_id: &PeerId, conn: &ConnectionId, _: &ConnectedPoint) {
@@ -214,6 +233,18 @@ impl NetworkBehaviour for Identify {
         self.pending_push.remove(peer_id);
     }
 
+    fn inject_new_listen_addr(&mut self, _addr: &Multiaddr) {
+        if self.config.push_listen_addr_updates {
+            self.pending_push.extend(self.connected.keys());
+        }
+    }
+
+    fn inject_expired_listen_addr(&mut self, _addr: &Multiaddr) {
+        if self.config.push_listen_addr_updates {
+            self.pending_push.extend(self.connected.keys());
+        }
+    }
+
     fn inject_event(
         &mut self,
         peer_id: PeerId,
@@ -341,7 +372,7 @@ impl NetworkBehaviour for Identify {
                             Poll::Ready(Err(err)) => {
                                 let event = IdentifyEvent::Error {
                                     peer_id: peer,
-                                    error: ProtocolsHandlerUpgrErr::Upgrade(UpgradeError::Apply(err.into()))
+                                    error: ProtocolsHandlerUpgrErr::Upgrade(UpgradeError::Apply(err))
                                 };
                                 return Poll::Ready(NetworkBehaviourAction::GenerateEvent(event));
                             },