Remove Debug bound on tributary::P2p

Moves all of the Libp2p code to a dedicated directory. Makes the Heartbeat task
abstract over any P2p network.

Cargo.lock

@@ -10498,7 +10498,6 @@ dependencies = [
 name = "tendermint-machine"
 version = "0.2.0"
 dependencies = [
- "async-trait",
  "futures-channel",
  "futures-util",
  "hex",
@@ -10941,7 +10940,6 @@ dependencies = [
 name = "tributary-chain"
 version = "0.1.0"
 dependencies = [
- "async-trait",
  "blake2",
  "ciphersuite",
  "flexible-transcript",

coordinator/src/p2p/heartbeat.rs

@@ -1,9 +1,10 @@
 use core::future::Future;
-
 use std::time::{Duration, SystemTime};
 
 use serai_client::validator_sets::primitives::ValidatorSet;
 
+use futures_util::FutureExt;
+
 use tributary::{ReadWrite, Block, Tributary, TributaryReader};
 
 use serai_db::*;
@@ -11,10 +12,7 @@ use serai_task::ContinuallyRan;
 
 use crate::{
   tributary::Transaction,
-  p2p::{
-    reqres::{Request, Response},
-    P2p,
-  },
+  p2p::{Peer, P2p},
 };
 
 // Amount of blocks in a minute
@@ -28,14 +26,14 @@ pub const BLOCKS_PER_BATCH: usize = BLOCKS_PER_MINUTE + 1;
 ///
 /// If the other validator has more blocks then we do, they're expected to inform us. This forms
 /// the sync protocol for our Tributaries.
-struct HeartbeatTask<TD: Db> {
+struct HeartbeatTask<TD: Db, P: P2p> {
   set: ValidatorSet,
-  tributary: Tributary<TD, Transaction, P2p>,
+  tributary: Tributary<TD, Transaction, P>,
   reader: TributaryReader<TD, Transaction>,
-  p2p: P2p,
+  p2p: P,
 }
 
-impl<TD: Db> ContinuallyRan for HeartbeatTask<TD> {
+impl<TD: Db, P: P2p> ContinuallyRan for HeartbeatTask<TD, P> {
   fn run_iteration(&mut self) -> impl Send + Future<Output = Result<bool, String>> {
     async move {
       // If our blockchain hasn't had a block in the past minute, trigger the heartbeat protocol
@@ -74,8 +72,10 @@ impl<TD: Db> ContinuallyRan for HeartbeatTask<TD> {
               tip = self.reader.tip();
               tip_is_stale = false;
             }
-            let request = Request::Heartbeat { set: self.set, latest_block_hash: tip };
-            let Ok(Response::Blocks(blocks)) = peer.send(request).await else { continue 'peer };
+            // Necessary due to https://github.com/rust-lang/rust/issues/100013
+            let Some(blocks) = peer.send_heartbeat(self.set, tip).boxed().await else {
+              continue 'peer;
+            };
 
             // This is the final batch if it has less than the maximum amount of blocks
             // (signifying there weren't more blocks after this to fill the batch with)

coordinator/src/p2p/libp2p/authenticate.rs

@@ -19,14 +19,15 @@ use libp2p::{
   noise,
 };
 
-use crate::p2p::{validators::Validators, peer_id_from_public};
+use crate::p2p::libp2p::{validators::Validators, peer_id_from_public};
 
 const PROTOCOL: &str = "/serai/coordinator/validators";
 
-struct OnlyValidators {
-  validators: Arc<RwLock<Validators>>,
-  serai_key: Zeroizing<Keypair>,
-  noise_keypair: identity::Keypair,
+#[derive(Clone)]
+pub(crate) struct OnlyValidators {
+  pub(crate) validators: Arc<RwLock<Validators>>,
+  pub(crate) serai_key: Zeroizing<Keypair>,
+  pub(crate) noise_keypair: identity::Keypair,
 }
 
 impl OnlyValidators {

coordinator/src/p2p/libp2p/dial.rs

@@ -14,7 +14,7 @@ use libp2p::{
 
 use serai_task::ContinuallyRan;
 
-use crate::p2p::{PORT, Peers, validators::Validators};
+use crate::p2p::libp2p::{PORT, Peers, validators::Validators};
 
 const TARGET_PEERS_PER_NETWORK: usize = 5;
 /*
@@ -28,13 +28,19 @@ const TARGET_PEERS_PER_NETWORK: usize = 5;
 */
 // TODO const TARGET_DIALED_PEERS_PER_NETWORK: usize = 3;
 
-struct DialTask {
+pub(crate) struct DialTask {
   serai: Serai,
   validators: Validators,
   peers: Peers,
   to_dial: mpsc::UnboundedSender<DialOpts>,
 }
 
+impl DialTask {
+  pub(crate) fn new(serai: Serai, peers: Peers, to_dial: mpsc::UnboundedSender<DialOpts>) -> Self {
+    DialTask { serai: serai.clone(), validators: Validators::new(serai), peers, to_dial }
+  }
+}
+
 impl ContinuallyRan for DialTask {
   // Only run every five minutes, not the default of every five seconds
   const DELAY_BETWEEN_ITERATIONS: u64 = 5 * 60;

coordinator/src/p2p/libp2p/gossip.rs

@@ -15,7 +15,7 @@ pub use libp2p::gossipsub::Event;
 use serai_cosign::SignedCosign;
 
 // Block size limit + 16 KB of space for signatures/metadata
-const MAX_LIBP2P_GOSSIP_MESSAGE_SIZE: usize = tributary::BLOCK_SIZE_LIMIT + 16384;
+pub(crate) const MAX_LIBP2P_GOSSIP_MESSAGE_SIZE: usize = tributary::BLOCK_SIZE_LIMIT + 16384;
 
 const KEEP_ALIVE_INTERVAL: Duration = Duration::from_secs(80);
 

coordinator/src/p2p/libp2p/mod.rs

@@ -0,0 +1,214 @@
+use core::{future::Future, time::Duration};
+use std::{
+  sync::Arc,
+  collections::{HashSet, HashMap},
+};
+
+use zeroize::Zeroizing;
+use schnorrkel::Keypair;
+
+use serai_client::{
+  primitives::{NetworkId, PublicKey},
+  validator_sets::primitives::ValidatorSet,
+  Serai,
+};
+
+use tokio::sync::{mpsc, oneshot, RwLock};
+
+use serai_task::{Task, ContinuallyRan};
+
+use libp2p::{
+  multihash::Multihash,
+  identity::{self, PeerId},
+  tcp::Config as TcpConfig,
+  yamux,
+  swarm::NetworkBehaviour,
+  SwarmBuilder,
+};
+
+use crate::p2p::TributaryBlockWithCommit;
+
+/// A struct to sync the validators from the Serai node in order to keep track of them.
+mod validators;
+use validators::UpdateValidatorsTask;
+
+/// The authentication protocol upgrade to limit the P2P network to active validators.
+mod authenticate;
+use authenticate::OnlyValidators;
+
+/// The dial task, to find new peers to connect to
+mod dial;
+use dial::DialTask;
+
+/// The request-response messages and behavior
+mod reqres;
+use reqres::{Request, Response};
+
+/// The gossip messages and behavior
+mod gossip;
+
+/// The swarm task, running it and dispatching to/from it
+mod swarm;
+use swarm::SwarmTask;
+
+const PORT: u16 = 30563; // 5132 ^ (('c' << 8) | 'o')
+
+// usize::max, manually implemented, as max isn't a const fn
+const MAX_LIBP2P_MESSAGE_SIZE: usize =
+  if gossip::MAX_LIBP2P_GOSSIP_MESSAGE_SIZE > reqres::MAX_LIBP2P_REQRES_MESSAGE_SIZE {
+    gossip::MAX_LIBP2P_GOSSIP_MESSAGE_SIZE
+  } else {
+    reqres::MAX_LIBP2P_REQRES_MESSAGE_SIZE
+  };
+
+fn peer_id_from_public(public: PublicKey) -> PeerId {
+  // 0 represents the identity Multihash, that no hash was performed
+  // It's an internal constant so we can't refer to the constant inside libp2p
+  PeerId::from_multihash(Multihash::wrap(0, &public.0).unwrap()).unwrap()
+}
+
+struct Peer<'a> {
+  outbound_requests: &'a mpsc::UnboundedSender<(PeerId, Request, oneshot::Sender<Response>)>,
+  id: PeerId,
+}
+impl crate::p2p::Peer<'_> for Peer<'_> {
+  fn send_heartbeat(
+    &self,
+    set: ValidatorSet,
+    latest_block_hash: [u8; 32],
+  ) -> impl Send + Future<Output = Option<Vec<TributaryBlockWithCommit>>> {
+    const HEARBEAT_TIMEOUT: Duration = Duration::from_secs(5);
+    async move {
+      let request = Request::Heartbeat { set, latest_block_hash };
+      let (sender, receiver) = oneshot::channel();
+      self
+        .outbound_requests
+        .send((self.id, request, sender))
+        .expect("outbound requests recv channel was dropped?");
+      match tokio::time::timeout(HEARBEAT_TIMEOUT, receiver).await.ok()?.ok()? {
+        Response::None => Some(vec![]),
+        Response::Blocks(blocks) => Some(blocks),
+        // TODO: Disconnect this peer
+        Response::NotableCosigns(_) => None,
+      }
+    }
+  }
+}
+
+#[derive(Clone)]
+struct Peers {
+  peers: Arc<RwLock<HashMap<NetworkId, HashSet<PeerId>>>>,
+}
+
+#[derive(NetworkBehaviour)]
+struct Behavior {
+  reqres: reqres::Behavior,
+  gossip: gossip::Behavior,
+}
+
+#[derive(Clone)]
+struct Libp2p {
+  peers: Peers,
+  outbound_requests: mpsc::UnboundedSender<(PeerId, Request, oneshot::Sender<Response>)>,
+}
+
+impl Libp2p {
+  pub(crate) fn new(serai_key: &Zeroizing<Keypair>, serai: Serai) -> Libp2p {
+    // Define the object we track peers with
+    let peers = Peers { peers: Arc::new(RwLock::new(HashMap::new())) };
+
+    // Define the dial task
+    let (dial_task_def, dial_task) = Task::new();
+    let (to_dial_send, to_dial_recv) = mpsc::unbounded_channel();
+    tokio::spawn(
+      DialTask::new(serai.clone(), peers.clone(), to_dial_send)
+        .continually_run(dial_task_def, vec![]),
+    );
+
+    // Define the Validators object used for validating new connections
+    let connection_validators = UpdateValidatorsTask::spawn(serai.clone());
+    let new_only_validators = |noise_keypair: &identity::Keypair| -> Result<_, ()> {
+      Ok(OnlyValidators {
+        serai_key: serai_key.clone(),
+        validators: connection_validators.clone(),
+        noise_keypair: noise_keypair.clone(),
+      })
+    };
+
+    let new_yamux = || {
+      let mut config = yamux::Config::default();
+      // 1 MiB default + max message size
+      config.set_max_buffer_size((1024 * 1024) + MAX_LIBP2P_MESSAGE_SIZE);
+      // 256 KiB default + max message size
+      config.set_receive_window_size(((256 * 1024) + MAX_LIBP2P_MESSAGE_SIZE).try_into().unwrap());
+      config
+    };
+
+    let behavior = Behavior { reqres: reqres::new_behavior(), gossip: gossip::new_behavior() };
+
+    let mut swarm = SwarmBuilder::with_existing_identity(identity::Keypair::generate_ed25519())
+      .with_tokio()
+      .with_tcp(TcpConfig::default().nodelay(false), new_only_validators, new_yamux)
+      .unwrap()
+      .with_behaviour(|_| behavior)
+      .unwrap()
+      .build();
+    swarm.listen_on(format!("/ip4/0.0.0.0/tcp/{PORT}").parse().unwrap()).unwrap();
+    swarm.listen_on(format!("/ip6/::/tcp/{PORT}").parse().unwrap()).unwrap();
+
+    let swarm_validators = UpdateValidatorsTask::spawn(serai);
+
+    let (gossip_send, gossip_recv) = mpsc::unbounded_channel();
+    let (signed_cosigns_send, signed_cosigns_recv) = mpsc::unbounded_channel();
+    let (tributary_gossip_send, tributary_gossip_recv) = mpsc::unbounded_channel();
+
+    let (outbound_requests_send, outbound_requests_recv) = mpsc::unbounded_channel();
+
+    let (heartbeat_requests_send, heartbeat_requests_recv) = mpsc::unbounded_channel();
+    let (notable_cosign_requests_send, notable_cosign_requests_recv) = mpsc::unbounded_channel();
+    let (inbound_request_responses_send, inbound_request_responses_recv) =
+      mpsc::unbounded_channel();
+
+    // Create the swarm task
+    SwarmTask::spawn(
+      dial_task,
+      to_dial_recv,
+      swarm_validators,
+      peers,
+      swarm,
+      gossip_recv,
+      signed_cosigns_send,
+      tributary_gossip_send,
+      outbound_requests_recv,
+      heartbeat_requests_send,
+      notable_cosign_requests_send,
+      inbound_request_responses_recv,
+    );
+
+    // gossip_send, signed_cosigns_recv, tributary_gossip_recv, outbound_requests_send,
+    // heartbeat_requests_recv, notable_cosign_requests_recv, inbound_request_responses_send
+    todo!("TODO");
+  }
+}
+
+impl tributary::P2p for Libp2p {
+  fn broadcast(&self, genesis: [u8; 32], msg: Vec<u8>) -> impl Send + Future<Output = ()> {
+    async move { todo!("TODO") }
+  }
+}
+
+impl crate::p2p::P2p for Libp2p {
+  type Peer<'a> = Peer<'a>;
+  fn peers(&self, network: NetworkId) -> impl Send + Future<Output = Vec<Self::Peer<'_>>> {
+    async move {
+      let Some(peer_ids) = self.peers.peers.read().await.get(&network).cloned() else {
+        return vec![];
+      };
+      let mut res = vec![];
+      for id in peer_ids {
+        res.push(Peer { outbound_requests: &self.outbound_requests, id });
+      }
+      res
+    }
+  }
+}

coordinator/src/p2p/libp2p/reqres.rs

@@ -15,9 +15,11 @@ pub use request_response::Message;
 
 use serai_cosign::SignedCosign;
 
+use crate::p2p::TributaryBlockWithCommit;
+
 /// The maximum message size for the request-response protocol
 // This is derived from the heartbeat message size as it's our largest message
-const MAX_LIBP2P_REQRES_MESSAGE_SIZE: usize =
+pub(crate) const MAX_LIBP2P_REQRES_MESSAGE_SIZE: usize =
   (tributary::BLOCK_SIZE_LIMIT * crate::p2p::heartbeat::BLOCKS_PER_BATCH) + 1024;
 
 const PROTOCOL: &str = "/serai/coordinator/reqres/1.0.0";
@@ -36,24 +38,17 @@ pub(crate) enum Request {
   NotableCosigns { global_session: [u8; 32] },
 }
 
-/// A tributary block and its commit.
-#[derive(Clone, BorshSerialize, BorshDeserialize)]
-pub(crate) struct TributaryBlockWithCommit {
-  pub(crate) block: Vec<u8>,
-  pub(crate) commit: Vec<u8>,
-}
-
 /// Responses which can be received via the request-response protocol.
 #[derive(Clone, BorshSerialize, BorshDeserialize)]
 pub(crate) enum Response {
-  NoResponse,
+  None,
   Blocks(Vec<TributaryBlockWithCommit>),
   NotableCosigns(Vec<SignedCosign>),
 }
 impl fmt::Debug for Response {
   fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
     match self {
-      Response::NoResponse => fmt.debug_struct("Response::NoResponse").finish(),
+      Response::None => fmt.debug_struct("Response::None").finish(),
       Response::Blocks(_) => fmt.debug_struct("Response::Block").finish_non_exhaustive(),
       Response::NotableCosigns(_) => {
         fmt.debug_struct("Response::NotableCosigns").finish_non_exhaustive()

coordinator/src/p2p/libp2p/swarm.rs

@@ -21,13 +21,16 @@ use libp2p::{
   swarm::{dial_opts::DialOpts, SwarmEvent, Swarm},
 };
 
-use crate::p2p::{
+use crate::p2p::libp2p::{
   Peers, BehaviorEvent, Behavior,
   validators::Validators,
   reqres::{self, Request, Response},
   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,
@@ -54,12 +57,14 @@ 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>)>,
 
-  outbound_requests: mpsc::UnboundedReceiver<(PeerId, Request, oneshot::Sender<Option<Response>>)>,
-  outbound_request_responses: HashMap<RequestId, oneshot::Sender<Option<Response>>>,
+  outbound_requests: mpsc::UnboundedReceiver<(PeerId, Request, oneshot::Sender<Response>)>,
+  outbound_request_responses: HashMap<RequestId, oneshot::Sender<Response>>,
 
   inbound_request_response_channels: HashMap<RequestId, ResponseChannel<Response>>,
   heartbeat_requests: mpsc::UnboundedSender<(RequestId, ValidatorSet, [u8; 32])>,
@@ -99,35 +104,31 @@ 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) {
-            let _: Result<_, _> = channel.send(Some(response));
+            let _: Result<_, _> = channel.send(response);
           }
         }
       },
       reqres::Event::OutboundFailure { request_id, .. } => {
         // Send None as the response for the request
         if let Some(channel) = self.outbound_request_responses.remove(&request_id) {
-          let _: Result<_, _> = channel.send(None);
+          let _: Result<_, _> = channel.send(Response::None);
         }
       }
       reqres::Event::InboundFailure { .. } | reqres::Event::ResponseSent { .. } => {}
@@ -136,9 +137,19 @@ 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 +167,6 @@ 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 +262,7 @@ 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 +283,54 @@ impl SwarmTask {
       }
     }
   }
+
+  #[allow(clippy::too_many_arguments)]
+  pub(crate) fn spawn(
+    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<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(),
+    );
+  }
 }

coordinator/src/p2p/libp2p/validators.rs

@@ -1,4 +1,4 @@
-use core::borrow::Borrow;
+use core::{borrow::Borrow, future::Future};
 use std::{
   sync::Arc,
   collections::{HashSet, HashMap},
@@ -6,12 +6,14 @@ use std::{
 
 use serai_client::{primitives::NetworkId, validator_sets::primitives::Session, Serai};
 
+use serai_task::{Task, ContinuallyRan};
+
 use libp2p::PeerId;
 
 use futures_util::stream::{StreamExt, FuturesUnordered};
 use tokio::sync::RwLock;
 
-use crate::p2p::peer_id_from_public;
+use crate::p2p::libp2p::peer_id_from_public;
 
 pub(crate) struct Validators {
   serai: Serai,
@@ -25,6 +27,15 @@ pub(crate) struct Validators {
 }
 
 impl Validators {
+  pub(crate) fn new(serai: Serai) -> Self {
+    Validators {
+      serai,
+      sessions: HashMap::new(),
+      by_network: HashMap::new(),
+      validators: HashMap::new(),
+    }
+  }
+
   async fn session_changes(
     serai: impl Borrow<Serai>,
     sessions: impl Borrow<HashMap<NetworkId, Session>>,
@@ -103,8 +114,6 @@ impl Validators {
   }
 
   /// Update the view of the validators.
-  ///
-  /// Returns all validators removed from the active validator set.
   pub(crate) async fn update(&mut self) -> Result<(), String> {
     let session_changes = Self::session_changes(&self.serai, &self.sessions).await?;
     self.incorporate_session_changes(session_changes);
@@ -124,19 +133,51 @@ impl Validators {
   }
 }
 
-/// Update the view of the validators.
+/// A task which updates a set of validators.
 ///
-/// This minimizes the time an exclusive lock is held over the validators to minimize the
-/// disruption to functioning.
-///
-/// Returns all validators removed from the active validator set.
-pub(crate) async fn update_shared_validators(
-  validators: &Arc<RwLock<Validators>>,
-) -> Result<(), String> {
-  let session_changes = {
-    let validators = validators.read().await;
-    Validators::session_changes(validators.serai.clone(), validators.sessions.clone()).await?
-  };
-  validators.write().await.incorporate_session_changes(session_changes);
-  Ok(())
+/// The validators managed by this tak will have their exclusive lock held for a minimal amount of
+/// time while the update occurs to minimize the disruption to the services relying on it.
+pub(crate) struct UpdateValidatorsTask {
+  validators: Arc<RwLock<Validators>>,
+}
+
+impl UpdateValidatorsTask {
+  /// Spawn a new instance of the UpdateValidatorsTask.
+  ///
+  /// This returns a reference to the Validators it updates after spawning itself.
+  pub(crate) fn spawn(serai: Serai) -> Arc<RwLock<Validators>> {
+    // The validators which will be updated
+    let validators = Arc::new(RwLock::new(Validators::new(serai)));
+
+    // Define the task
+    let (update_validators_task, update_validators_task_handle) = Task::new();
+    // Forget the handle, as dropping the handle would stop the task
+    core::mem::forget(update_validators_task_handle);
+    // Spawn the task
+    tokio::spawn(
+      (Self { validators: validators.clone() }).continually_run(update_validators_task, vec![]),
+    );
+
+    // Return the validators
+    validators
+  }
+}
+
+impl ContinuallyRan for UpdateValidatorsTask {
+  // Only run every minute, not the default of every five seconds
+  const DELAY_BETWEEN_ITERATIONS: u64 = 60;
+  const MAX_DELAY_BETWEEN_ITERATIONS: u64 = 5 * 60;
+
+  fn run_iteration(&mut self) -> impl Send + Future<Output = Result<bool, String>> {
+    async move {
+      let session_changes = {
+        let validators = self.validators.read().await;
+        Validators::session_changes(validators.serai.clone(), validators.sessions.clone())
+          .await
+          .map_err(|e| format!("{e:?}"))?
+      };
+      self.validators.write().await.incorporate_session_changes(session_changes);
+      Ok(true)
+    }
+  }
 }

coordinator/src/p2p/mod.rs

@@ -1,94 +1,31 @@
 use core::future::Future;
-use std::{
-  sync::Arc,
-  collections::{HashSet, HashMap},
-};
 
-use serai_client::primitives::{NetworkId, PublicKey};
+use borsh::{BorshSerialize, BorshDeserialize};
 
-use tokio::sync::RwLock;
+use serai_client::{primitives::NetworkId, validator_sets::primitives::ValidatorSet};
 
-use serai_task::ContinuallyRan;
-
-use libp2p::{multihash::Multihash, identity::PeerId, swarm::NetworkBehaviour};
-
-/// A struct to sync the validators from the Serai node in order to keep track of them.
-mod validators;
-use validators::{Validators, update_shared_validators};
-
-/// The authentication protocol upgrade to limit the P2P network to active validators.
-mod authenticate;
-
-/// The dial task, to find new peers to connect to
-mod dial;
-
-/// The request-response messages and behavior
-mod reqres;
-use reqres::{Request, Response};
-
-/// The gossip messages and behavior
-mod gossip;
+/// The libp2p-backed P2p network
+mod libp2p;
 
 /// The heartbeat task, effecting sync of Tributaries
 mod heartbeat;
 
-/// The swarm task, running it and dispatching to/from it
-mod swarm;
-
-const PORT: u16 = 30563; // 5132 ^ (('c' << 8) | 'o')
-
-fn peer_id_from_public(public: PublicKey) -> PeerId {
-  // 0 represents the identity Multihash, that no hash was performed
-  // It's an internal constant so we can't refer to the constant inside libp2p
-  PeerId::from_multihash(Multihash::wrap(0, &public.0).unwrap()).unwrap()
+/// A tributary block and its commit.
+#[derive(Clone, BorshSerialize, BorshDeserialize)]
+pub(crate) struct TributaryBlockWithCommit {
+  pub(crate) block: Vec<u8>,
+  pub(crate) commit: Vec<u8>,
 }
 
-struct Peer;
-impl Peer {
-  async fn send(&self, request: Request) -> Result<Response, tokio::time::error::Elapsed> {
-    (async move { todo!("TODO") }).await
-  }
+trait Peer<'a>: Send {
+  fn send_heartbeat(
+    &self,
+    set: ValidatorSet,
+    latest_block_hash: [u8; 32],
+  ) -> impl Send + Future<Output = Option<Vec<TributaryBlockWithCommit>>>;
 }
 
-#[derive(Clone)]
-struct Peers {
-  peers: Arc<RwLock<HashMap<NetworkId, HashSet<PeerId>>>>,
-}
-
-#[derive(Clone, Debug)]
-struct P2p;
-impl P2p {
-  async fn peers(&self, set: NetworkId) -> Vec<Peer> {
-    (async move { todo!("TODO") }).await
-  }
-}
-
-#[async_trait::async_trait]
-impl tributary::P2p for P2p {
-  async fn broadcast(&self, genesis: [u8; 32], msg: Vec<u8>) {
-    todo!("TODO")
-  }
-}
-
-#[derive(NetworkBehaviour)]
-struct Behavior {
-  reqres: reqres::Behavior,
-  gossip: gossip::Behavior,
-}
-
-struct UpdateSharedValidatorsTask {
-  validators: Arc<RwLock<Validators>>,
-}
-
-impl ContinuallyRan for UpdateSharedValidatorsTask {
-  // Only run every minute, not the default of every five seconds
-  const DELAY_BETWEEN_ITERATIONS: u64 = 60;
-  const MAX_DELAY_BETWEEN_ITERATIONS: u64 = 5 * 60;
-
-  fn run_iteration(&mut self) -> impl Send + Future<Output = Result<bool, String>> {
-    async move {
-      update_shared_validators(&self.validators).await.map_err(|e| format!("{e:?}"))?;
-      Ok(true)
-    }
-  }
+trait P2p: Send + Sync + tributary::P2p {
+  type Peer<'a>: Peer<'a>;
+  fn peers(&self, network: NetworkId) -> impl Send + Future<Output = Vec<Self::Peer<'_>>>;
 }

coordinator/tributary/Cargo.toml

@@ -16,7 +16,6 @@ rustdoc-args = ["--cfg", "docsrs"]
 workspace = true
 
 [dependencies]
-async-trait = { version = "0.1", default-features = false }
 thiserror = { version = "2", default-features = false, features = ["std"] }
 
 subtle = { version = "^2", default-features = false, features = ["std"] }

coordinator/tributary/src/lib.rs

@@ -1,8 +1,6 @@
-use core::{marker::PhantomData, fmt::Debug};
+use core::{marker::PhantomData, fmt::Debug, future::Future};
 use std::{sync::Arc, io};
 
-use async_trait::async_trait;
-
 use zeroize::Zeroizing;
 
 use ciphersuite::{Ciphersuite, Ristretto};
@@ -131,20 +129,18 @@ pub trait ReadWrite: Sized {
   }
 }
 
-#[async_trait]
-pub trait P2p: 'static + Send + Sync + Clone + Debug {
+pub trait P2p: 'static + Send + Sync + Clone {
   /// Broadcast a message to all other members of the Tributary with the specified genesis.
   ///
   /// The Tributary will re-broadcast consensus messages on a fixed interval to ensure they aren't
   /// prematurely dropped from the P2P layer. THe P2P layer SHOULD perform content-based
   /// deduplication to ensure a sane amount of load.
-  async fn broadcast(&self, genesis: [u8; 32], msg: Vec<u8>);
+  fn broadcast(&self, genesis: [u8; 32], msg: Vec<u8>) -> impl Send + Future<Output = ()>;
 }
 
-#[async_trait]
 impl<P: P2p> P2p for Arc<P> {
-  async fn broadcast(&self, genesis: [u8; 32], msg: Vec<u8>) {
-    (*self).broadcast(genesis, msg).await
+  fn broadcast(&self, genesis: [u8; 32], msg: Vec<u8>) -> impl Send + Future<Output = ()> {
+    P::broadcast(self, genesis, msg)
   }
 }
 

coordinator/tributary/src/tendermint/mod.rs

@@ -1,8 +1,6 @@
-use core::ops::Deref;
+use core::{ops::Deref, future::Future};
 use std::{sync::Arc, collections::HashMap};
 
-use async_trait::async_trait;
-
 use subtle::ConstantTimeEq;
 use zeroize::{Zeroize, Zeroizing};
 
@@ -74,50 +72,52 @@ impl Signer {
   }
 }
 
-#[async_trait]
 impl SignerTrait for Signer {
   type ValidatorId = [u8; 32];
   type Signature = [u8; 64];
 
   /// Returns the validator's current ID. Returns None if they aren't a current validator.
-  async fn validator_id(&self) -> Option<Self::ValidatorId> {
-    Some((Ristretto::generator() * self.key.deref()).to_bytes())
+  fn validator_id(&self) -> impl Send + Future<Output = Option<Self::ValidatorId>> {
+    async move { Some((Ristretto::generator() * self.key.deref()).to_bytes()) }
   }
 
   /// Sign a signature with the current validator's private key.
-  async fn sign(&self, msg: &[u8]) -> Self::Signature {
-    let mut nonce = Zeroizing::new(RecommendedTranscript::new(b"Tributary Chain Tendermint Nonce"));
-    nonce.append_message(b"genesis", self.genesis);
-    nonce.append_message(b"key", Zeroizing::new(self.key.deref().to_repr()).as_ref());
-    nonce.append_message(b"message", msg);
-    let mut nonce = nonce.challenge(b"nonce");
+  fn sign(&self, msg: &[u8]) -> impl Send + Future<Output = Self::Signature> {
+    async move {
+      let mut nonce =
+        Zeroizing::new(RecommendedTranscript::new(b"Tributary Chain Tendermint Nonce"));
+      nonce.append_message(b"genesis", self.genesis);
+      nonce.append_message(b"key", Zeroizing::new(self.key.deref().to_repr()).as_ref());
+      nonce.append_message(b"message", msg);
+      let mut nonce = nonce.challenge(b"nonce");
 
-    let mut nonce_arr = [0; 64];
-    nonce_arr.copy_from_slice(nonce.as_ref());
+      let mut nonce_arr = [0; 64];
+      nonce_arr.copy_from_slice(nonce.as_ref());
 
-    let nonce_ref: &mut [u8] = nonce.as_mut();
-    nonce_ref.zeroize();
-    let nonce_ref: &[u8] = nonce.as_ref();
-    assert_eq!(nonce_ref, [0; 64].as_ref());
+      let nonce_ref: &mut [u8] = nonce.as_mut();
+      nonce_ref.zeroize();
+      let nonce_ref: &[u8] = nonce.as_ref();
+      assert_eq!(nonce_ref, [0; 64].as_ref());
 
-    let nonce =
-      Zeroizing::new(<Ristretto as Ciphersuite>::F::from_bytes_mod_order_wide(&nonce_arr));
-    nonce_arr.zeroize();
+      let nonce =
+        Zeroizing::new(<Ristretto as Ciphersuite>::F::from_bytes_mod_order_wide(&nonce_arr));
+      nonce_arr.zeroize();
 
-    assert!(!bool::from(nonce.ct_eq(&<Ristretto as Ciphersuite>::F::ZERO)));
+      assert!(!bool::from(nonce.ct_eq(&<Ristretto as Ciphersuite>::F::ZERO)));
 
-    let challenge = challenge(
-      self.genesis,
-      (Ristretto::generator() * self.key.deref()).to_bytes(),
-      (Ristretto::generator() * nonce.deref()).to_bytes().as_ref(),
-      msg,
-    );
+      let challenge = challenge(
+        self.genesis,
+        (Ristretto::generator() * self.key.deref()).to_bytes(),
+        (Ristretto::generator() * nonce.deref()).to_bytes().as_ref(),
+        msg,
+      );
 
-    let sig = SchnorrSignature::<Ristretto>::sign(&self.key, nonce, challenge).serialize();
+      let sig = SchnorrSignature::<Ristretto>::sign(&self.key, nonce, challenge).serialize();
 
-    let mut res = [0; 64];
-    res.copy_from_slice(&sig);
-    res
+      let mut res = [0; 64];
+      res.copy_from_slice(&sig);
+      res
+    }
   }
 }
 
@@ -274,7 +274,6 @@ pub const BLOCK_PROCESSING_TIME: u32 = 999;
 pub const LATENCY_TIME: u32 = 1667;
 pub const TARGET_BLOCK_TIME: u32 = BLOCK_PROCESSING_TIME + (3 * LATENCY_TIME);
 
-#[async_trait]
 impl<D: Db, T: TransactionTrait, P: P2p> Network for TendermintNetwork<D, T, P> {
   type Db = D;
 
@@ -300,111 +299,126 @@ impl<D: Db, T: TransactionTrait, P: P2p> Network for TendermintNetwork<D, T, P>
     self.validators.clone()
   }
 
-  async fn broadcast(&mut self, msg: SignedMessageFor<Self>) {
-    let mut to_broadcast = vec![TENDERMINT_MESSAGE];
-    to_broadcast.extend(msg.encode());
-    self.p2p.broadcast(self.genesis, to_broadcast).await
-  }
-
-  async fn slash(&mut self, validator: Self::ValidatorId, slash_event: SlashEvent) {
-    log::error!(
-      "validator {} triggered a slash event on tributary {} (with evidence: {})",
-      hex::encode(validator),
-      hex::encode(self.genesis),
-      matches!(slash_event, SlashEvent::WithEvidence(_)),
-    );
-
-    let signer = self.signer();
-    let Some(tx) = (match slash_event {
-      SlashEvent::WithEvidence(evidence) => {
-        // create an unsigned evidence tx
-        Some(TendermintTx::SlashEvidence(evidence))
-      }
-      SlashEvent::Id(_reason, _block, _round) => {
-        // TODO: Increase locally observed slash points
-        None
-      }
-    }) else {
-      return;
-    };
-
-    // add tx to blockchain and broadcast to peers
-    let mut to_broadcast = vec![TRANSACTION_MESSAGE];
-    tx.write(&mut to_broadcast).unwrap();
-    if self.blockchain.write().await.add_transaction::<Self>(
-      true,
-      Transaction::Tendermint(tx),
-      &self.signature_scheme(),
-    ) == Ok(true)
-    {
-      self.p2p.broadcast(signer.genesis, to_broadcast).await;
+  fn broadcast(&mut self, msg: SignedMessageFor<Self>) -> impl Send + Future<Output = ()> {
+    async move {
+      let mut to_broadcast = vec![TENDERMINT_MESSAGE];
+      to_broadcast.extend(msg.encode());
+      self.p2p.broadcast(self.genesis, to_broadcast).await
     }
   }
 
-  async fn validate(&self, block: &Self::Block) -> Result<(), TendermintBlockError> {
-    let block =
-      Block::read::<&[u8]>(&mut block.0.as_ref()).map_err(|_| TendermintBlockError::Fatal)?;
-    self
-      .blockchain
-      .read()
-      .await
-      .verify_block::<Self>(&block, &self.signature_scheme(), false)
-      .map_err(|e| match e {
-        BlockError::NonLocalProvided(_) => TendermintBlockError::Temporal,
-        _ => {
-          log::warn!("Tributary Tendermint validate returning BlockError::Fatal due to {e:?}");
-          TendermintBlockError::Fatal
+  fn slash(
+    &mut self,
+    validator: Self::ValidatorId,
+    slash_event: SlashEvent,
+  ) -> impl Send + Future<Output = ()> {
+    async move {
+      log::error!(
+        "validator {} triggered a slash event on tributary {} (with evidence: {})",
+        hex::encode(validator),
+        hex::encode(self.genesis),
+        matches!(slash_event, SlashEvent::WithEvidence(_)),
+      );
+
+      let signer = self.signer();
+      let Some(tx) = (match slash_event {
+        SlashEvent::WithEvidence(evidence) => {
+          // create an unsigned evidence tx
+          Some(TendermintTx::SlashEvidence(evidence))
         }
-      })
+        SlashEvent::Id(_reason, _block, _round) => {
+          // TODO: Increase locally observed slash points
+          None
+        }
+      }) else {
+        return;
+      };
+
+      // add tx to blockchain and broadcast to peers
+      let mut to_broadcast = vec![TRANSACTION_MESSAGE];
+      tx.write(&mut to_broadcast).unwrap();
+      if self.blockchain.write().await.add_transaction::<Self>(
+        true,
+        Transaction::Tendermint(tx),
+        &self.signature_scheme(),
+      ) == Ok(true)
+      {
+        self.p2p.broadcast(signer.genesis, to_broadcast).await;
+      }
+    }
   }
 
-  async fn add_block(
+  fn validate(
+    &self,
+    block: &Self::Block,
+  ) -> impl Send + Future<Output = Result<(), TendermintBlockError>> {
+    async move {
+      let block =
+        Block::read::<&[u8]>(&mut block.0.as_ref()).map_err(|_| TendermintBlockError::Fatal)?;
+      self
+        .blockchain
+        .read()
+        .await
+        .verify_block::<Self>(&block, &self.signature_scheme(), false)
+        .map_err(|e| match e {
+          BlockError::NonLocalProvided(_) => TendermintBlockError::Temporal,
+          _ => {
+            log::warn!("Tributary Tendermint validate returning BlockError::Fatal due to {e:?}");
+            TendermintBlockError::Fatal
+          }
+        })
+    }
+  }
+
+  fn add_block(
     &mut self,
     serialized_block: Self::Block,
     commit: Commit<Self::SignatureScheme>,
-  ) -> Option<Self::Block> {
-    let invalid_block = || {
-      // There's a fatal flaw in the code, it's behind a hard fork, or the validators turned
-      // malicious
-      // All justify a halt to then achieve social consensus from
-      // TODO: Under multiple validator sets, a small validator set turning malicious knocks
-      // off the entire network. That's an unacceptable DoS.
-      panic!("validators added invalid block to tributary {}", hex::encode(self.genesis));
-    };
+  ) -> impl Send + Future<Output = Option<Self::Block>> {
+    async move {
+      let invalid_block = || {
+        // There's a fatal flaw in the code, it's behind a hard fork, or the validators turned
+        // malicious
+        // All justify a halt to then achieve social consensus from
+        // TODO: Under multiple validator sets, a small validator set turning malicious knocks
+        // off the entire network. That's an unacceptable DoS.
+        panic!("validators added invalid block to tributary {}", hex::encode(self.genesis));
+      };
 
-    // Tendermint should only produce valid commits
-    assert!(self.verify_commit(serialized_block.id(), &commit));
+      // Tendermint should only produce valid commits
+      assert!(self.verify_commit(serialized_block.id(), &commit));
 
-    let Ok(block) = Block::read::<&[u8]>(&mut serialized_block.0.as_ref()) else {
-      return invalid_block();
-    };
+      let Ok(block) = Block::read::<&[u8]>(&mut serialized_block.0.as_ref()) else {
+        return invalid_block();
+      };
 
-    let encoded_commit = commit.encode();
-    loop {
-      let block_res = self.blockchain.write().await.add_block::<Self>(
-        &block,
-        encoded_commit.clone(),
-        &self.signature_scheme(),
-      );
-      match block_res {
-        Ok(()) => {
-          // If we successfully added this block, break
-          break;
+      let encoded_commit = commit.encode();
+      loop {
+        let block_res = self.blockchain.write().await.add_block::<Self>(
+          &block,
+          encoded_commit.clone(),
+          &self.signature_scheme(),
+        );
+        match block_res {
+          Ok(()) => {
+            // If we successfully added this block, break
+            break;
+          }
+          Err(BlockError::NonLocalProvided(hash)) => {
+            log::error!(
+              "missing provided transaction {} which other validators on tributary {} had",
+              hex::encode(hash),
+              hex::encode(self.genesis)
+            );
+            tokio::time::sleep(core::time::Duration::from_secs(5)).await;
+          }
+          _ => return invalid_block(),
         }
-        Err(BlockError::NonLocalProvided(hash)) => {
-          log::error!(
-            "missing provided transaction {} which other validators on tributary {} had",
-            hex::encode(hash),
-            hex::encode(self.genesis)
-          );
-          tokio::time::sleep(core::time::Duration::from_secs(5)).await;
-        }
-        _ => return invalid_block(),
       }
-    }
 
-    Some(TendermintBlock(
-      self.blockchain.write().await.build_block::<Self>(&self.signature_scheme()).serialize(),
-    ))
+      Some(TendermintBlock(
+        self.blockchain.write().await.build_block::<Self>(&self.signature_scheme()).serialize(),
+      ))
+    }
   }
 }

coordinator/tributary/src/tests/p2p.rs

@@ -1,11 +1,12 @@
+use core::future::Future;
+
 pub use crate::P2p;
 
 #[derive(Clone, Debug)]
 pub struct DummyP2p;
 
-#[async_trait::async_trait]
 impl P2p for DummyP2p {
-  async fn broadcast(&self, _: [u8; 32], _: Vec<u8>) {
-    unimplemented!()
+  fn broadcast(&self, _: [u8; 32], _: Vec<u8>) -> impl Send + Future<Output = ()> {
+    async move { unimplemented!() }
   }
 }

coordinator/tributary/src/tests/tendermint.rs

@@ -1,4 +1,7 @@
+use core::future::Future;
+
 use tendermint::ext::Network;
+
 use crate::{
   P2p, TendermintTx,
   tendermint::{TARGET_BLOCK_TIME, TendermintNetwork},
@@ -11,10 +14,9 @@ fn assert_target_block_time() {
   #[derive(Clone, Debug)]
   pub struct DummyP2p;
 
-  #[async_trait::async_trait]
   impl P2p for DummyP2p {
-    async fn broadcast(&self, _: [u8; 32], _: Vec<u8>) {
-      unimplemented!()
+    fn broadcast(&self, _: [u8; 32], _: Vec<u8>) -> impl Send + Future<Output = ()> {
+      async move { unimplemented!() }
     }
   }
 

coordinator/tributary/tendermint/Cargo.toml

@@ -16,7 +16,6 @@ rustdoc-args = ["--cfg", "docsrs"]
 workspace = true
 
 [dependencies]
-async-trait = { version = "0.1", default-features = false }
 thiserror = { version = "2", default-features = false, features = ["std"] }
 
 hex = { version = "0.4", default-features = false, features = ["std"] }

coordinator/tributary/tendermint/src/ext.rs

@@ -1,7 +1,6 @@
-use core::{hash::Hash, fmt::Debug};
+use core::{hash::Hash, fmt::Debug, future::Future};
 use std::{sync::Arc, collections::HashSet};
 
-use async_trait::async_trait;
 use thiserror::Error;
 
 use parity_scale_codec::{Encode, Decode};
@@ -34,7 +33,6 @@ pub struct BlockNumber(pub u64);
 pub struct RoundNumber(pub u32);
 
 /// A signer for a validator.
-#[async_trait]
 pub trait Signer: Send + Sync {
   // Type used to identify validators.
   type ValidatorId: ValidatorId;
@@ -42,22 +40,21 @@ pub trait Signer: Send + Sync {
   type Signature: Signature;
 
   /// Returns the validator's current ID. Returns None if they aren't a current validator.
-  async fn validator_id(&self) -> Option<Self::ValidatorId>;
+  fn validator_id(&self) -> impl Send + Future<Output = Option<Self::ValidatorId>>;
   /// Sign a signature with the current validator's private key.
-  async fn sign(&self, msg: &[u8]) -> Self::Signature;
+  fn sign(&self, msg: &[u8]) -> impl Send + Future<Output = Self::Signature>;
 }
 
-#[async_trait]
 impl<S: Signer> Signer for Arc<S> {
   type ValidatorId = S::ValidatorId;
   type Signature = S::Signature;
 
-  async fn validator_id(&self) -> Option<Self::ValidatorId> {
-    self.as_ref().validator_id().await
+  fn validator_id(&self) -> impl Send + Future<Output = Option<Self::ValidatorId>> {
+    self.as_ref().validator_id()
   }
 
-  async fn sign(&self, msg: &[u8]) -> Self::Signature {
-    self.as_ref().sign(msg).await
+  fn sign(&self, msg: &[u8]) -> impl Send + Future<Output = Self::Signature> {
+    self.as_ref().sign(msg)
   }
 }
 
@@ -210,7 +207,6 @@ pub trait Block: Send + Sync + Clone + PartialEq + Eq + Debug + Encode + Decode
 }
 
 /// Trait representing the distributed system Tendermint is providing consensus over.
-#[async_trait]
 pub trait Network: Sized + Send + Sync {
   /// The database used to back this.
   type Db: serai_db::Db;
@@ -229,6 +225,7 @@ pub trait Network: Sized + Send + Sync {
   /// This should include both the time to download the block and the actual processing time.
   ///
   /// BLOCK_PROCESSING_TIME + (3 * LATENCY_TIME) must be divisible by 1000.
+  // TODO: Redefine as Duration
   const BLOCK_PROCESSING_TIME: u32;
   /// Network latency time in milliseconds.
   ///
@@ -280,15 +277,19 @@ pub trait Network: Sized + Send + Sync {
   /// Switching to unauthenticated channels in a system already providing authenticated channels is
   /// not recommended as this is a minor, temporal inefficiency, while downgrading channels may
   /// have wider implications.
-  async fn broadcast(&mut self, msg: SignedMessageFor<Self>);
+  fn broadcast(&mut self, msg: SignedMessageFor<Self>) -> impl Send + Future<Output = ()>;
 
   /// Trigger a slash for the validator in question who was definitively malicious.
   ///
   /// The exact process of triggering a slash is undefined and left to the network as a whole.
-  async fn slash(&mut self, validator: Self::ValidatorId, slash_event: SlashEvent);
+  fn slash(
+    &mut self,
+    validator: Self::ValidatorId,
+    slash_event: SlashEvent,
+  ) -> impl Send + Future<Output = ()>;
 
   /// Validate a block.
-  async fn validate(&self, block: &Self::Block) -> Result<(), BlockError>;
+  fn validate(&self, block: &Self::Block) -> impl Send + Future<Output = Result<(), BlockError>>;
 
   /// Add a block, returning the proposal for the next one.
   ///
@@ -298,9 +299,9 @@ pub trait Network: Sized + Send + Sync {
   /// This deviates from the paper which will have a local node refuse to decide on a block it
   /// considers invalid. This library acknowledges the network did decide on it, leaving handling
   /// of it to the network, and outside of this scope.
-  async fn add_block(
+  fn add_block(
     &mut self,
     block: Self::Block,
     commit: Commit<Self::SignatureScheme>,
-  ) -> Option<Self::Block>;
+  ) -> impl Send + Future<Output = Option<Self::Block>>;
 }

coordinator/tributary/tendermint/tests/ext.rs

@@ -1,10 +1,9 @@
+use core::future::Future;
 use std::{
   sync::Arc,
   time::{UNIX_EPOCH, SystemTime, Duration},
 };
 
-use async_trait::async_trait;
-
 use parity_scale_codec::{Encode, Decode};
 
 use futures_util::sink::SinkExt;
@@ -21,20 +20,21 @@ type TestValidatorId = u16;
 type TestBlockId = [u8; 4];
 
 struct TestSigner(u16);
-#[async_trait]
 impl Signer for TestSigner {
   type ValidatorId = TestValidatorId;
   type Signature = [u8; 32];
 
-  async fn validator_id(&self) -> Option<TestValidatorId> {
-    Some(self.0)
+  fn validator_id(&self) -> impl Send + Future<Output = Option<TestValidatorId>> {
+    async move { Some(self.0) }
   }
 
-  async fn sign(&self, msg: &[u8]) -> [u8; 32] {
-    let mut sig = [0; 32];
-    sig[.. 2].copy_from_slice(&self.0.to_le_bytes());
-    sig[2 .. (2 + 30.min(msg.len()))].copy_from_slice(&msg[.. 30.min(msg.len())]);
-    sig
+  fn sign(&self, msg: &[u8]) -> impl Send + Future<Output = [u8; 32]> {
+    async move {
+      let mut sig = [0; 32];
+      sig[.. 2].copy_from_slice(&self.0.to_le_bytes());
+      sig[2 .. (2 + 30.min(msg.len()))].copy_from_slice(&msg[.. 30.min(msg.len())]);
+      sig
+    }
   }
 }
 
@@ -111,7 +111,6 @@ struct TestNetwork(
   Arc<RwLock<Vec<(MessageSender<Self>, SyncedBlockSender<Self>, SyncedBlockResultReceiver)>>>,
 );
 
-#[async_trait]
 impl Network for TestNetwork {
   type Db = MemDb;