fix(kad): prevent simultaneous dials to peer

By default, dialing is prevented when already connected. `kad` already checks this manually before doing dials. By changing the condition from `Disconnected` to `NotDialing`, we prevent simultaneous dials to a peer.

Pull-Request: #4224.

protocols/kad/CHANGELOG.md

@@ -1,3 +1,10 @@
+## 0.44.3 - unreleased
+
+- Prevent simultaneous dials to peers.
+  See [PR 4224].
+
+[PR 4224]: https://github.com/libp2p/rust-libp2p/pull/4224
+
 ## 0.44.2
 
 - Allow to explicitly set `Mode::{Client,Server}`.

protocols/kad/Cargo.toml

@@ -3,7 +3,7 @@ name = "libp2p-kad"
 edition = "2021"
 rust-version = "1.65.0"
 description = "Kademlia protocol for libp2p"
-version = "0.44.2"
+version = "0.44.3"
 authors = ["Parity Technologies <admin@parity.io>"]
 license = "MIT"
 repository = "https://github.com/libp2p/rust-libp2p"

protocols/kad/src/behaviour.rs

@@ -579,7 +579,9 @@ where
                     }
                     kbucket::InsertResult::Pending { disconnected } => {
                         self.queued_events.push_back(ToSwarm::Dial {
-                            opts: DialOpts::peer_id(disconnected.into_preimage()).build(),
+                            opts: DialOpts::peer_id(disconnected.into_preimage())
+                                .condition(dial_opts::PeerCondition::NotDialing)
+                                .build(),
                         });
                         RoutingUpdate::Pending
                     }
@@ -1306,6 +1308,7 @@ where
                                 if !self.connected_peers.contains(disconnected.preimage()) {
                                     self.queued_events.push_back(ToSwarm::Dial {
                                         opts: DialOpts::peer_id(disconnected.into_preimage())
+                                            .condition(dial_opts::PeerCondition::NotDialing)
                                             .build(),
                                     })
                                 }
@@ -2508,7 +2511,9 @@ where
                         } else if &peer_id != self.kbuckets.local_key().preimage() {
                             query.inner.pending_rpcs.push((peer_id, event));
                             self.queued_events.push_back(ToSwarm::Dial {
-                                opts: DialOpts::peer_id(peer_id).build(),
+                                opts: DialOpts::peer_id(peer_id)
+                                    .condition(dial_opts::PeerCondition::NotDialing)
+                                    .build(),
                             });
                         }
                     }