swarm/: Allow disconnecting from Swarm and NetworkBehaviour (#2110)

Add `ExpandedSwarm::disconnect_peer_id` and
`NetworkBehaviourAction::CloseConnection` to close connections to a specific
peer via an `ExpandedSwarm` or `NetworkBehaviour`.

Co-authored-by: Max Inden <mail@max-inden.de>

protocols/gossipsub/src/behaviour.rs

@@ -3202,6 +3202,9 @@ where
                 NetworkBehaviourAction::ReportObservedAddr { address, score } => {
                     NetworkBehaviourAction::ReportObservedAddr { address, score }
                 }
+                NetworkBehaviourAction::CloseConnection { peer_id, connection } => {
+                    NetworkBehaviourAction::CloseConnection { peer_id, connection }
+                }
             });
         }
 

protocols/request-response/src/throttled.rs

@@ -657,7 +657,9 @@ where
                 | NetworkBehaviourAction::NotifyHandler { peer_id, handler, event } =>
                     NetworkBehaviourAction::NotifyHandler { peer_id, handler, event },
                 | NetworkBehaviourAction::ReportObservedAddr { address, score } =>
-                    NetworkBehaviourAction::ReportObservedAddr { address, score }
+                    NetworkBehaviourAction::ReportObservedAddr { address, score },
+                | NetworkBehaviourAction::CloseConnection { peer_id, connection } =>
+                    NetworkBehaviourAction::CloseConnection { peer_id, connection }
             };
 
             return Poll::Ready(event)

swarm-derive/src/lib.rs

@@ -479,6 +479,9 @@ fn build_struct(ast: &DeriveInput, data_struct: &DataStruct) -> TokenStream {
                     std::task::Poll::Ready(#network_behaviour_action::ReportObservedAddr { address, score }) => {
                         return std::task::Poll::Ready(#network_behaviour_action::ReportObservedAddr { address, score });
                     }
+                    std::task::Poll::Ready(#network_behaviour_action::CloseConnection { peer_id, connection }) => {
+                        return std::task::Poll::Ready(#network_behaviour_action::CloseConnection { peer_id, connection });
+                    }
                     std::task::Poll::Pending => break,
                 }
             }

swarm/CHANGELOG.md

@@ -15,7 +15,12 @@
 
   See [PR 2100] for details.
 
+- Add `ExpandedSwarm::disconnect_peer_id` and
+  `NetworkBehaviourAction::CloseConnection` to close connections to a specific
+  peer via an `ExpandedSwarm` or `NetworkBehaviour`. See [PR 2110] for details.
+
 [PR 2100]: https://github.com/libp2p/rust-libp2p/pull/2100
+[PR 2110]: https://github.com/libp2p/rust-libp2p/pull/2110/
 
 # 0.29.0 [2021-04-13]
 

swarm/src/behaviour.rs

@@ -293,6 +293,23 @@ pub enum NetworkBehaviourAction<TInEvent, TOutEvent> {
         /// relative to other observed addresses.
         score: AddressScore,
     },
+
+    /// Instructs the `Swarm` to initiate a graceful close of one or all connections
+    /// with the given peer.
+    ///
+    /// Note: Closing a connection via
+    /// [`NetworkBehaviourAction::CloseConnection`] does not inform the
+    /// corresponding [`ProtocolsHandler`].
+    /// Closing a connection via a [`ProtocolsHandler`] can be done
+    /// either in a collaborative manner across [`ProtocolsHandler`]s
+    /// with [`ProtocolsHandler::connection_keep_alive`] or directly with
+    /// [`ProtocolsHandlerEvent::Close`](crate::ProtocolsHandlerEvent::Close).
+    CloseConnection {
+        /// The peer to disconnect.
+        peer_id: PeerId,
+        /// Whether to close a specific or all connections to the given peer.
+        connection: CloseConnection,
+    }
 }
 
 impl<TInEvent, TOutEvent> NetworkBehaviourAction<TInEvent, TOutEvent> {
@@ -312,7 +329,9 @@ impl<TInEvent, TOutEvent> NetworkBehaviourAction<TInEvent, TOutEvent> {
                     event: f(event)
                 },
             NetworkBehaviourAction::ReportObservedAddr { address, score } =>
-                NetworkBehaviourAction::ReportObservedAddr { address, score }
+                NetworkBehaviourAction::ReportObservedAddr { address, score },
+            NetworkBehaviourAction::CloseConnection { peer_id, connection } =>
+                NetworkBehaviourAction::CloseConnection { peer_id, connection }
         }
     }
 
@@ -328,7 +347,9 @@ impl<TInEvent, TOutEvent> NetworkBehaviourAction<TInEvent, TOutEvent> {
             NetworkBehaviourAction::NotifyHandler { peer_id, handler, event } =>
                 NetworkBehaviourAction::NotifyHandler { peer_id, handler, event },
             NetworkBehaviourAction::ReportObservedAddr { address, score } =>
-                NetworkBehaviourAction::ReportObservedAddr { address, score }
+                NetworkBehaviourAction::ReportObservedAddr { address, score },
+            NetworkBehaviourAction::CloseConnection { peer_id, connection } =>
+                NetworkBehaviourAction::CloseConnection { peer_id, connection }
         }
     }
 }
@@ -373,3 +394,18 @@ impl Default for DialPeerCondition {
         DialPeerCondition::Disconnected
     }
 }
+
+/// The options which connections to close.
+#[derive(Debug, Clone)]
+pub enum CloseConnection {
+    /// Disconnect a particular connection.
+    One(ConnectionId),
+    /// Disconnect all connections.
+    All,
+}
+
+impl Default for CloseConnection {
+    fn default() -> Self {
+        CloseConnection::All
+    }
+}