Build the swarm

Moves UpdateSharedValidatorsTask to validators.rs. While prior planned to
re-use a validators object across connecting and peer state management, the
current plan is to use an independent validators object for each to minimize
any contention. They should be built infrequently enough, and cheap enough to
update in the majority case (due to quickly checking if an update is needed),
that this is fine.

coordinator/src/p2p/swarm.rs

@@ -28,6 +28,9 @@ use crate::p2p::{
   gossip,
 };
 
+const KEEP_ALIVE_INTERVAL: Duration = Duration::from_secs(80);
+const TIME_BETWEEN_REBUILD_PEERS: Duration = Duration::from_secs(10 * 60);
+
 /*
   `SwarmTask` handles everything we need the `Swarm` object for. The goal is to minimize the
   contention on this task. Unfortunately, the `Swarm` object itself is needed for a variety of
@@ -43,7 +46,7 @@ use crate::p2p::{
   - Dispatching received requests
   - Sending responses
 */
-struct SwarmTask {
+pub(crate) struct SwarmTask {
   dial_task: TaskHandle,
   to_dial: mpsc::UnboundedReceiver<DialOpts>,
   last_dial_task_run: Instant,
@@ -54,6 +57,8 @@ struct SwarmTask {
 
   swarm: Swarm<Behavior>,
 
+  last_message: Instant,
+
   gossip: mpsc::UnboundedReceiver<gossip::Message>,
   signed_cosigns: mpsc::UnboundedSender<SignedCosign>,
   tributary_gossip: mpsc::UnboundedSender<(ValidatorSet, Vec<u8>)>,
@@ -99,24 +104,21 @@ impl SwarmTask {
   fn handle_reqres(&mut self, event: reqres::Event) {
     match event {
       reqres::Event::Message { message, .. } => match message {
-        reqres::Message::Request { request_id, request, channel } => {
-          match request {
-            // TODO: Send these
-            reqres::Request::KeepAlive => {
-              let _: Result<_, _> =
-                self.swarm.behaviour_mut().reqres.send_response(channel, Response::NoResponse);
-            }
-            reqres::Request::Heartbeat { set, latest_block_hash } => {
-              self.inbound_request_response_channels.insert(request_id, channel);
-              let _: Result<_, _> =
-                self.heartbeat_requests.send((request_id, set, latest_block_hash));
-            }
-            reqres::Request::NotableCosigns { global_session } => {
-              self.inbound_request_response_channels.insert(request_id, channel);
-              let _: Result<_, _> = self.notable_cosign_requests.send((request_id, global_session));
-            }
+        reqres::Message::Request { request_id, request, channel } => match request {
+          reqres::Request::KeepAlive => {
+            let _: Result<_, _> =
+              self.swarm.behaviour_mut().reqres.send_response(channel, Response::None);
           }
-        }
+          reqres::Request::Heartbeat { set, latest_block_hash } => {
+            self.inbound_request_response_channels.insert(request_id, channel);
+            let _: Result<_, _> =
+              self.heartbeat_requests.send((request_id, set, latest_block_hash));
+          }
+          reqres::Request::NotableCosigns { global_session } => {
+            self.inbound_request_response_channels.insert(request_id, channel);
+            let _: Result<_, _> = self.notable_cosign_requests.send((request_id, global_session));
+          }
+        },
         reqres::Message::Response { request_id, response } => {
           // Send Some(response) as the response for the request
           if let Some(channel) = self.outbound_request_responses.remove(&request_id) {
@@ -136,9 +138,19 @@ impl SwarmTask {
 
   async fn run(mut self) {
     loop {
+      let time_till_keep_alive = Instant::now().saturating_duration_since(self.last_message);
       let time_till_rebuild_peers = self.rebuild_peers_at.saturating_duration_since(Instant::now());
 
       tokio::select! {
+        () = tokio::time::sleep(time_till_keep_alive) => {
+          let peers = self.swarm.connected_peers().copied().collect::<Vec<_>>();
+          let behavior = self.swarm.behaviour_mut();
+          for peer in peers {
+            behavior.reqres.send_request(&peer, Request::KeepAlive);
+          }
+          self.last_message = Instant::now();
+        }
+
         // Dial peers we're instructed to
         dial_opts = self.to_dial.recv() => {
           let dial_opts = dial_opts.expect("DialTask was closed?");
@@ -156,8 +168,6 @@ impl SwarmTask {
           We also use this to disconnect all peers who are no longer active in any network.
         */
         () = tokio::time::sleep(time_till_rebuild_peers) => {
-          const TIME_BETWEEN_REBUILD_PEERS: Duration = Duration::from_secs(10 * 60);
-
           let validators_by_network = self.validators.read().await.by_network().clone();
           let connected_peers = self.swarm.connected_peers().copied().collect::<HashSet<_>>();
 
@@ -253,6 +263,7 @@ impl SwarmTask {
           let topic = message.topic();
           let message = borsh::to_vec(&message).unwrap();
           let _: Result<_, _> = self.swarm.behaviour_mut().gossip.publish(topic, message);
+          self.last_message = Instant::now();
         }
 
         request = self.outbound_requests.recv() => {
@@ -273,4 +284,58 @@ impl SwarmTask {
       }
     }
   }
+
+  #[allow(clippy::too_many_arguments)]
+  pub(crate) fn new(
+    dial_task: TaskHandle,
+    to_dial: mpsc::UnboundedReceiver<DialOpts>,
+
+    validators: Arc<RwLock<Validators>>,
+    peers: Peers,
+
+    swarm: Swarm<Behavior>,
+
+    gossip: mpsc::UnboundedReceiver<gossip::Message>,
+    signed_cosigns: mpsc::UnboundedSender<SignedCosign>,
+    tributary_gossip: mpsc::UnboundedSender<(ValidatorSet, Vec<u8>)>,
+
+    outbound_requests: mpsc::UnboundedReceiver<(
+      PeerId,
+      Request,
+      oneshot::Sender<Option<Response>>,
+    )>,
+
+    heartbeat_requests: mpsc::UnboundedSender<(RequestId, ValidatorSet, [u8; 32])>,
+    notable_cosign_requests: mpsc::UnboundedSender<(RequestId, [u8; 32])>,
+    inbound_request_responses: mpsc::UnboundedReceiver<(RequestId, Response)>,
+  ) {
+    tokio::spawn(
+      SwarmTask {
+        dial_task,
+        to_dial,
+        last_dial_task_run: Instant::now(),
+
+        validators,
+        peers,
+        rebuild_peers_at: Instant::now() + TIME_BETWEEN_REBUILD_PEERS,
+
+        swarm,
+
+        last_message: Instant::now(),
+
+        gossip,
+        signed_cosigns,
+        tributary_gossip,
+
+        outbound_requests,
+        outbound_request_responses: HashMap::new(),
+
+        inbound_request_response_channels: HashMap::new(),
+        heartbeat_requests,
+        notable_cosign_requests,
+        inbound_request_responses,
+      }
+      .run(),
+    );
+  }
 }