Revert EpochStarted messages

examples/simulation.rs

@@ -434,16 +434,11 @@ fn main() {
         .map(|_| Transaction::new(args.flag_tx_size))
         .collect();
     let new_honey_badger = |netinfo: NetworkInfo<NodeId>| {
-        let (dhb, dhb_step) = DynamicHoneyBadger::builder()
-            .build(netinfo)
-            .expect("`DynamicHoneyBadger` builder failed");
-        let (qhb, qhb_step) = QueueingHoneyBadger::builder(dhb)
+        let dyn_hb = DynamicHoneyBadger::builder().build(netinfo);
+        QueueingHoneyBadger::builder(dyn_hb)
             .batch_size(args.flag_b)
             .build_with_transactions(txs.clone())
-            .expect("instantiate QueueingHoneyBadger");
-        let mut step = dhb_step.convert();
-        step.extend(qhb_step);
-        (qhb, step)
+            .expect("instantiate QueueingHoneyBadger")
     };
     let hw_quality = HwQuality {
         latency: Duration::from_millis(args.flag_lag),

src/dynamic_honey_badger/builder.rs

@@ -71,10 +71,7 @@ where
     }
 
     /// Creates a new Dynamic Honey Badger instance with an empty buffer.
-    pub fn build(
-        &mut self,
-        netinfo: NetworkInfo<N>,
-    ) -> Result<(DynamicHoneyBadger<C, N>, Step<C, N>)> {
+    pub fn build(&mut self, netinfo: NetworkInfo<N>) -> DynamicHoneyBadger<C, N> {
         let DynamicHoneyBadgerBuilder {
             max_future_epochs,
             rng,
@@ -83,12 +80,12 @@ where
         } = self;
         let max_future_epochs = *max_future_epochs;
         let arc_netinfo = Arc::new(netinfo.clone());
-        let (honey_badger, hb_step) = HoneyBadger::builder(arc_netinfo.clone())
+        let honey_badger = HoneyBadger::builder(arc_netinfo.clone())
             .max_future_epochs(max_future_epochs)
             .rng(rng.sub_rng())
             .subset_handling_strategy(subset_handling_strategy.clone())
             .build();
-        let mut dhb = DynamicHoneyBadger {
+        DynamicHoneyBadger {
             netinfo,
             max_future_epochs,
             start_epoch: 0,
@@ -98,23 +95,18 @@ where
             key_gen_state: None,
             incoming_queue: Vec::new(),
             rng: Box::new(rng.sub_rng()),
-        };
-        let step = dhb.process_output(hb_step)?;
-        Ok((dhb, step))
+        }
     }
 
     /// Creates a new `DynamicHoneyBadger` configured to start a new network as a single validator.
-    pub fn build_first_node(
-        &mut self,
-        our_id: N,
-    ) -> Result<(DynamicHoneyBadger<C, N>, Step<C, N>)> {
+    pub fn build_first_node(&mut self, our_id: N) -> Result<DynamicHoneyBadger<C, N>> {
         let sk_set = SecretKeySet::random(0, &mut self.rng)?;
         let pk_set = sk_set.public_keys();
         let sks = sk_set.secret_key_share(0)?;
         let sk: SecretKey = self.rng.gen();
         let pub_keys = once((our_id.clone(), sk.public_key())).collect();
         let netinfo = NetworkInfo::new(our_id, sks, pk_set, sk, pub_keys);
-        self.build(netinfo)
+        Ok(self.build(netinfo))
     }
 
     /// Creates a new `DynamicHoneyBadger` configured to join the network at the epoch specified in
@@ -133,27 +125,23 @@ where
             join_plan.pub_keys,
         );
         let arc_netinfo = Arc::new(netinfo.clone());
-        let (honey_badger, hb_step) = HoneyBadger::builder(arc_netinfo.clone())
+        let honey_badger = HoneyBadger::builder(arc_netinfo.clone())
             .max_future_epochs(self.max_future_epochs)
             .build();
-        let start_epoch = join_plan.epoch;
         let mut dhb = DynamicHoneyBadger {
             netinfo,
             max_future_epochs: self.max_future_epochs,
-            start_epoch,
+            start_epoch: join_plan.epoch,
             vote_counter: VoteCounter::new(arc_netinfo, join_plan.epoch),
             key_gen_msg_buffer: Vec::new(),
             honey_badger,
             key_gen_state: None,
             incoming_queue: Vec::new(),
             rng: Box::new(self.rng.sub_rng()),
         };
-        let mut step = dhb.process_output(hb_step)?;
-        match join_plan.change {
-            ChangeState::InProgress(ref change) => {
-                step.extend(dhb.update_key_gen(join_plan.epoch, change)?)
-            }
-            ChangeState::None | ChangeState::Complete(..) => (),
+        let step = match join_plan.change {
+            ChangeState::InProgress(ref change) => dhb.update_key_gen(join_plan.epoch, change)?,
+            ChangeState::None | ChangeState::Complete(..) => Step::default(),
         };
         Ok((dhb, step))
     }

src/dynamic_honey_badger/dynamic_honey_badger.rs

@@ -193,6 +193,10 @@ where
         sender_id: &N,
         message: HbMessage<N>,
     ) -> Result<Step<C, N>> {
+        if !self.netinfo.is_node_validator(sender_id) {
+            info!("Unknown sender {:?} of message {:?}", sender_id, message);
+            return Err(ErrorKind::UnknownSender.into());
+        }
         // Handle the message.
         let step = self
             .honey_badger
@@ -246,7 +250,7 @@ where
     }
 
     /// Processes all pending batches output by Honey Badger.
-    pub(super) fn process_output(
+    fn process_output(
         &mut self,
         hb_step: honey_badger::Step<InternalContrib<C, N>, N>,
     ) -> Result<Step<C, N>> {
@@ -295,8 +299,7 @@ where
                 // If DKG completed, apply the change, restart Honey Badger, and inform the user.
                 debug!("{:?} DKG for {:?} complete!", self.our_id(), kgs.change);
                 self.netinfo = kgs.key_gen.into_network_info()?;
-                let step_on_restart = self.restart_honey_badger(batch.epoch + 1)?;
-                step.extend(step_on_restart);
+                self.restart_honey_badger(batch.epoch + 1);
                 batch.set_change(ChangeState::Complete(kgs.change), &self.netinfo);
             } else if let Some(change) = self.vote_counter.compute_winner().cloned() {
                 // If there is a new change, restart DKG. Inform the user about the current change.
@@ -330,7 +333,7 @@ where
         } {
             info!("{:?} No-op change: {:?}", self.our_id(), change);
         }
-        let mut step = self.restart_honey_badger(epoch)?;
+        self.restart_honey_badger(epoch);
         // TODO: This needs to be the same as `num_faulty` will be in the _new_
         // `NetworkInfo` if the change goes through. It would be safer to deduplicate.
         let threshold = (pub_keys.len() - 1) / 3;
@@ -339,25 +342,23 @@ where
         let (key_gen, part) = SyncKeyGen::new(&mut self.rng, our_id, sk, pub_keys, threshold)?;
         self.key_gen_state = Some(KeyGenState::new(key_gen, change.clone()));
         if let Some(part) = part {
-            let step_on_send = self.send_transaction(KeyGenMessage::Part(part))?;
-            step.extend(step_on_send);
+            self.send_transaction(KeyGenMessage::Part(part))
+        } else {
+            Ok(Step::default())
         }
-        Ok(step)
     }
 
     /// Starts a new `HoneyBadger` instance and resets the vote counter.
-    fn restart_honey_badger(&mut self, epoch: u64) -> Result<Step<C, N>> {
+    fn restart_honey_badger(&mut self, epoch: u64) {
         self.start_epoch = epoch;
         self.key_gen_msg_buffer.retain(|kg_msg| kg_msg.0 >= epoch);
         let netinfo = Arc::new(self.netinfo.clone());
         let counter = VoteCounter::new(netinfo.clone(), epoch);
         mem::replace(&mut self.vote_counter, counter);
-        let (hb, hb_step) = HoneyBadger::builder(netinfo)
+        self.honey_badger = HoneyBadger::builder(netinfo)
             .max_future_epochs(self.max_future_epochs)
             .rng(self.rng.sub_rng())
             .build();
-        self.honey_badger = hb;
-        self.process_output(hb_step)
     }
 
     /// Handles a `Part` message that was output by Honey Badger.

src/dynamic_honey_badger/error.rs

@@ -29,6 +29,8 @@ pub enum ErrorKind {
     HandleHoneyBadgerMessageHoneyBadger(honey_badger::Error),
     #[fail(display = "SyncKeyGen error: {}", _0)]
     SyncKeyGen(sync_key_gen::Error),
+    #[fail(display = "Unknown sender")]
+    UnknownSender,
 }
 
 /// A dynamic honey badger error.

src/honey_badger/builder.rs

@@ -5,17 +5,14 @@ use std::sync::Arc;
 use rand::{self, Rand, Rng};
 use serde::{Deserialize, Serialize};
 
-use super::{HoneyBadger, Message, Step};
+use super::HoneyBadger;
 use honey_badger::SubsetHandlingStrategy;
-use messaging::{NetworkInfo, Target};
+use messaging::NetworkInfo;
 use traits::{Contribution, NodeIdT};
 use util::SubRng;
 
 /// A Honey Badger builder, to configure the parameters and create new instances of `HoneyBadger`.
-pub struct HoneyBadgerBuilder<C, N>
-where
-    N: Rand,
-{
+pub struct HoneyBadgerBuilder<C, N> {
     /// Shared network data.
     netinfo: Arc<NetworkInfo<N>>,
     /// The maximum number of future epochs for which we handle messages simultaneously.
@@ -65,26 +62,17 @@ where
         self
     }
 
-    /// Creates a new Honey Badger instance in epoch 0 and makes the initial `Step` on that
-    /// instance.
-    pub fn build(&mut self) -> (HoneyBadger<C, N>, Step<C, N>) {
-        let hb = HoneyBadger {
+    /// Creates a new Honey Badger instance.
+    pub fn build(&mut self) -> HoneyBadger<C, N> {
+        HoneyBadger {
             netinfo: self.netinfo.clone(),
             epoch: 0,
             has_input: false,
             epochs: BTreeMap::new(),
             max_future_epochs: self.max_future_epochs as u64,
             incoming_queue: BTreeMap::new(),
-            remote_epochs: BTreeMap::new(),
             rng: Box::new(self.rng.sub_rng()),
             subset_handling_strategy: self.subset_handling_strategy.clone(),
-        };
-        let step = if self.netinfo.is_validator() {
-            // The first message in an epoch announces the epoch transition.
-            Target::All.message(Message::EpochStarted(0)).into()
-        } else {
-            Step::default()
-        };
-        (hb, step)
+        }
     }
 }

src/honey_badger/error.rs

@@ -19,8 +19,8 @@ pub enum ErrorKind {
     HandleSubsetMessage(subset::Error),
     #[fail(display = "Threshold decryption error: {}", _0)]
     ThresholdDecryption(threshold_decryption::Error),
-    #[fail(display = "HoneyBadger message sender is not a validator")]
-    SenderNotValidator,
+    #[fail(display = "Unknown sender")]
+    UnknownSender,
 }
 
 /// A honey badger error.

src/honey_badger/honey_badger.rs

@@ -9,7 +9,7 @@ use serde::{Deserialize, Serialize};
 
 use super::epoch_state::EpochState;
 use super::{Batch, Error, ErrorKind, HoneyBadgerBuilder, Message, MessageContent, Result};
-use messaging::{self, DistAlgorithm, NetworkInfo, Target};
+use messaging::{self, DistAlgorithm, NetworkInfo};
 use traits::{Contribution, NodeIdT};
 
 pub use super::epoch_state::SubsetHandlingStrategy;
@@ -28,8 +28,6 @@ pub struct HoneyBadger<C, N: Rand> {
     pub(super) max_future_epochs: u64,
     /// Messages for future epochs that couldn't be handled yet.
     pub(super) incoming_queue: BTreeMap<u64, Vec<(N, MessageContent<N>)>>,
-    /// Known current epochs of remote nodes.
-    pub(super) remote_epochs: BTreeMap<N, u64>,
     /// A random number generator used for secret key generation.
     // Boxed to avoid overloading the algorithm's type with more generics.
     pub(super) rng: Box<dyn Rng + Send + Sync>,
@@ -50,7 +48,6 @@ where
             .field("epochs", &self.epochs)
             .field("max_future_epochs", &self.max_future_epochs)
             .field("incoming_queue", &self.incoming_queue)
-            .field("remote_epochs", &self.remote_epochs)
             .field("rng", &"<RNG>")
             .finish()
     }
@@ -118,27 +115,10 @@ where
 
     /// Handles a message received from `sender_id`.
     fn handle_message(&mut self, sender_id: &N, message: Message<N>) -> Result<Step<C, N>> {
-        match message {
-            Message::HoneyBadger { epoch, content } => {
-                if !self.netinfo.is_node_validator(sender_id) {
-                    return Err(ErrorKind::SenderNotValidator.into());
-                }
-                self.handle_honey_badger_message(sender_id, epoch, content)
-            }
-            Message::EpochStarted(epoch) => {
-                self.handle_epoch_started(sender_id, epoch);
-                Ok(Step::default())
-            }
+        if !self.netinfo.is_node_validator(sender_id) {
+            return Err(ErrorKind::UnknownSender.into());
         }
-    }
-
-    /// Handles a Honey Badger algorithm message in a given epoch.
-    fn handle_honey_badger_message(
-        &mut self,
-        sender_id: &N,
-        epoch: u64,
-        content: MessageContent<N>,
-    ) -> Result<Step<C, N>> {
+        let Message { epoch, content } = message;
         if epoch > self.epoch + self.max_future_epochs {
             // Postpone handling this message.
             self.incoming_queue
@@ -155,17 +135,6 @@ where
         Ok(Step::default())
     }
 
-    /// Handles an epoch start announcement.
-    fn handle_epoch_started(&mut self, sender_id: &N, epoch: u64) {
-        self.remote_epochs
-            .entry(sender_id.clone())
-            .and_modify(|e| {
-                if *e < epoch {
-                    *e = epoch;
-                }
-            }).or_insert(epoch);
-    }
-
     /// Returns `true` if input for the current epoch has already been provided.
     pub fn has_input(&self) -> bool {
         !self.netinfo.is_validator() || self.has_input
@@ -186,10 +155,7 @@ where
         self.epoch += 1;
         self.has_input = false;
         let max_epoch = self.epoch + self.max_future_epochs;
-        // The first message in an epoch announces the epoch transition.
-        let mut step: Step<C, N> = Target::All
-            .message(Message::EpochStarted(self.epoch))
-            .into();
+        let mut step = Step::default();
         if let Some(messages) = self.incoming_queue.remove(&max_epoch) {
             let epoch_state = self.epoch_state_mut(max_epoch)?;
             for (sender_id, content) in messages {

src/honey_badger/message.rs

@@ -4,7 +4,7 @@ use subset;
 use threshold_decryption;
 
 /// The content of a `HoneyBadger` message. It should be further annotated with an epoch.
-#[derive(Clone, Debug, Deserialize, PartialEq, Rand, Serialize)]
+#[derive(Clone, Debug, Deserialize, Rand, Serialize)]
 pub enum MessageContent<N: Rand> {
     /// A message belonging to the subset algorithm in the given epoch.
     Subset(subset::Message<N>),
@@ -17,7 +17,7 @@ pub enum MessageContent<N: Rand> {
 
 impl<N: Rand> MessageContent<N> {
     pub fn with_epoch(self, epoch: u64) -> Message<N> {
-        Message::HoneyBadger {
+        Message {
             epoch,
             content: self,
         }
@@ -26,25 +26,13 @@ impl<N: Rand> MessageContent<N> {
 
 /// A message sent to or received from another node's Honey Badger instance.
 #[derive(Clone, Debug, Deserialize, Rand, Serialize)]
-pub enum Message<N: Rand> {
-    /// A Honey Badger algorithm message annotated with the epoch number.
-    HoneyBadger {
-        epoch: u64,
-        content: MessageContent<N>,
-    },
-    /// A Honey Badger participant uses this message to announce its transition to the given
-    /// epoch. This message informs the recipients that this participant now accepts messages for
-    /// `max_future_epochs + 1` epochs counting from the given one, and drops any incoming messages
-    /// from earlier epochs.
-    EpochStarted(u64),
+pub struct Message<N: Rand> {
+    pub(super) epoch: u64,
+    pub(super) content: MessageContent<N>,
 }
 
 impl<N: Rand> Message<N> {
-    /// Returns the epoch from which the message originated.
     pub fn epoch(&self) -> u64 {
-        match *self {
-            Message::HoneyBadger { epoch, .. } => epoch,
-            Message::EpochStarted(epoch) => epoch,
-        }
+        self.epoch
     }
 }

src/subset.rs

@@ -62,7 +62,7 @@ pub type Result<T> = ::std::result::Result<T, Error>;
 type ProposedValue = Vec<u8>;
 
 /// Message from Subset to remote nodes.
-#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, Rand)]
+#[derive(Serialize, Deserialize, Clone, Debug, Rand)]
 pub enum Message<N: Rand> {
     /// A message for the broadcast algorithm concerning the set element proposed by the given node.
     Broadcast(N, broadcast::Message),