SingleAttestation full implementation

beacon_node/beacon_chain/src/attestation_verification.rs

@@ -475,7 +475,11 @@ impl<'a, T: BeaconChainTypes> IndexedAggregatedAttestation<'a, T> {
         // MAXIMUM_GOSSIP_CLOCK_DISPARITY allowance).
         //
         // We do not queue future attestations for later processing.
-        verify_propagation_slot_range(&chain.slot_clock, attestation, &chain.spec)?;
+        verify_attestation_propagation_slot_range::<T::SlotClock, T::EthSpec>(
+            &chain.slot_clock,
+            attestation.data().slot,
+            &chain.spec,
+        )?;
 
         // Check the attestation's epoch matches its target.
         if attestation.data().slot.epoch(T::EthSpec::slots_per_epoch())
@@ -538,7 +542,12 @@ impl<'a, T: BeaconChainTypes> IndexedAggregatedAttestation<'a, T> {
         //
         // Attestations must be for a known block. If the block is unknown, we simply drop the
         // attestation and do not delay consideration for later.
-        let head_block = verify_head_block_is_known(chain, attestation, None)?;
+        let head_block = verify_head_block_is_known(
+            chain,
+            attestation.data().beacon_block_root,
+            attestation.data().slot,
+            None,
+        )?;
 
         // Check the attestation target root is consistent with the head root.
         //
@@ -547,7 +556,11 @@ impl<'a, T: BeaconChainTypes> IndexedAggregatedAttestation<'a, T> {
         //
         // Whilst this attestation *technically* could be used to add value to a block, it is
         // invalid in the spirit of the protocol. Here we choose safety over profit.
-        verify_attestation_target_root::<T::EthSpec>(&head_block, attestation)?;
+        verify_attestation_target_root::<T::EthSpec>(
+            &head_block,
+            attestation.data().target.root,
+            attestation.data().slot,
+        )?;
 
         // Ensure that the attestation has participants.
         if attestation.is_aggregation_bits_zero() {
@@ -807,7 +820,11 @@ impl<'a, T: BeaconChainTypes> IndexedUnaggregatedAttestation<'a, T> {
         // MAXIMUM_GOSSIP_CLOCK_DISPARITY allowance).
         //
         // We do not queue future attestations for later processing.
-        verify_propagation_slot_range(&chain.slot_clock, attestation, &chain.spec)?;
+        verify_attestation_propagation_slot_range::<T::SlotClock, T::EthSpec>(
+            &chain.slot_clock,
+            attestation.data().slot,
+            &chain.spec,
+        )?;
 
         // Check to ensure that the attestation is "unaggregated". I.e., it has exactly one
         // aggregation bit set.
@@ -823,11 +840,19 @@ impl<'a, T: BeaconChainTypes> IndexedUnaggregatedAttestation<'a, T> {
         // attestation and do not delay consideration for later.
         //
         // Enforce a maximum skip distance for unaggregated attestations.
-        let head_block =
-            verify_head_block_is_known(chain, attestation, chain.config.import_max_skip_slots)?;
+        let head_block = verify_head_block_is_known(
+            chain,
+            attestation.data().beacon_block_root,
+            attestation.data().slot,
+            chain.config.import_max_skip_slots,
+        )?;
 
         // Check the attestation target root is consistent with the head root.
-        verify_attestation_target_root::<T::EthSpec>(&head_block, attestation)?;
+        verify_attestation_target_root::<T::EthSpec>(
+            &head_block,
+            attestation.data().target.root,
+            attestation.data().slot,
+        )?;
 
         Ok(())
     }
@@ -1072,36 +1097,37 @@ impl<'a, T: BeaconChainTypes> VerifiedUnaggregatedAttestation<'a, T> {
 /// Case (1) is the exact thing we're trying to detect. However case (2) is a little different, but
 /// it's still fine to reject here because there's no need for us to handle attestations that are
 /// already finalized.
-fn verify_head_block_is_known<T: BeaconChainTypes>(
+pub fn verify_head_block_is_known<T: BeaconChainTypes>(
     chain: &BeaconChain<T>,
-    attestation: AttestationRef<T::EthSpec>,
+    attestation_beacon_block_root: Hash256,
+    attestation_slot: Slot,
     max_skip_slots: Option<u64>,
 ) -> Result<ProtoBlock, Error> {
     let block_opt = chain
         .canonical_head
         .fork_choice_read_lock()
-        .get_block(&attestation.data().beacon_block_root)
+        .get_block(&attestation_beacon_block_root)
         .or_else(|| {
             chain
                 .early_attester_cache
-                .get_proto_block(attestation.data().beacon_block_root)
+                .get_proto_block(attestation_beacon_block_root)
         });
 
     if let Some(block) = block_opt {
         // Reject any block that exceeds our limit on skipped slots.
         if let Some(max_skip_slots) = max_skip_slots {
-            if attestation.data().slot > block.slot + max_skip_slots {
+            if attestation_slot > block.slot + max_skip_slots {
                 return Err(Error::TooManySkippedSlots {
                     head_block_slot: block.slot,
-                    attestation_slot: attestation.data().slot,
+                    attestation_slot,
                 });
             }
         }
 
         Ok(block)
-    } else if chain.is_pre_finalization_block(attestation.data().beacon_block_root)? {
+    } else if chain.is_pre_finalization_block(attestation_beacon_block_root)? {
         Err(Error::HeadBlockFinalized {
-            beacon_block_root: attestation.data().beacon_block_root,
+            beacon_block_root: attestation_beacon_block_root,
         })
     } else {
         // The block is either:
@@ -1111,21 +1137,20 @@ fn verify_head_block_is_known<T: BeaconChainTypes>(
         // 2) A post-finalization block that we don't know about yet. We'll queue
         //    the attestation until the block becomes available (or we time out).
         Err(Error::UnknownHeadBlock {
-            beacon_block_root: attestation.data().beacon_block_root,
+            beacon_block_root: attestation_beacon_block_root,
         })
     }
 }
 
-/// Verify that the `attestation` is within the acceptable gossip propagation range, with reference
+/// Verify that the `attestation_slot` is within the acceptable gossip propagation range, with reference
 /// to the current slot of the `chain`.
 ///
 /// Accounts for `MAXIMUM_GOSSIP_CLOCK_DISPARITY`.
-pub fn verify_propagation_slot_range<S: SlotClock, E: EthSpec>(
+pub fn verify_attestation_propagation_slot_range<S: SlotClock, E: EthSpec>(
     slot_clock: &S,
-    attestation: AttestationRef<E>,
+    attestation_slot: Slot,
     spec: &ChainSpec,
 ) -> Result<(), Error> {
-    let attestation_slot = attestation.data().slot;
     let latest_permissible_slot = slot_clock
         .now_with_future_tolerance(spec.maximum_gossip_clock_disparity())
         .ok_or(BeaconChainError::UnableToReadSlot)?;
@@ -1203,11 +1228,12 @@ pub fn verify_attestation_signature<T: BeaconChainTypes>(
 /// `attestation.data.beacon_block_root`.
 pub fn verify_attestation_target_root<E: EthSpec>(
     head_block: &ProtoBlock,
-    attestation: AttestationRef<E>,
+    attestation_target_root: Hash256,
+    attestation_slot: Slot,
 ) -> Result<(), Error> {
     // Check the attestation target root.
     let head_block_epoch = head_block.slot.epoch(E::slots_per_epoch());
-    let attestation_epoch = attestation.data().slot.epoch(E::slots_per_epoch());
+    let attestation_epoch = attestation_slot.epoch(E::slots_per_epoch());
     if head_block_epoch > attestation_epoch {
         // The epoch references an invalid head block from a future epoch.
         //
@@ -1220,7 +1246,7 @@ pub fn verify_attestation_target_root<E: EthSpec>(
         // Reference:
         // https://github.com/ethereum/eth2.0-specs/pull/2001#issuecomment-699246659
         return Err(Error::InvalidTargetRoot {
-            attestation: attestation.data().target.root,
+            attestation: attestation_target_root,
             // It is not clear what root we should expect in this case, since the attestation is
             // fundamentally invalid.
             expected: None,
@@ -1239,9 +1265,9 @@ pub fn verify_attestation_target_root<E: EthSpec>(
         };
 
         // Reject any attestation with an invalid target root.
-        if target_root != attestation.data().target.root {
+        if target_root != attestation_target_root {
             return Err(Error::InvalidTargetRoot {
-                attestation: attestation.data().target.root,
+                attestation: attestation_target_root,
                 expected: Some(target_root),
             });
         }

beacon_node/beacon_chain/src/beacon_chain.rs

@@ -60,6 +60,7 @@ use crate::persisted_beacon_chain::{PersistedBeaconChain, DUMMY_CANONICAL_HEAD_B
 use crate::persisted_fork_choice::PersistedForkChoice;
 use crate::pre_finalization_cache::PreFinalizationBlockCache;
 use crate::shuffling_cache::{BlockShufflingIds, ShufflingCache};
+use crate::single_attestation_verification::SingleAttestationVerification;
 use crate::sync_committee_verification::{
     Error as SyncCommitteeError, VerifiedSyncCommitteeMessage, VerifiedSyncContribution,
 };
@@ -72,6 +73,7 @@ use crate::{
     kzg_utils, metrics, AvailabilityPendingExecutedBlock, BeaconChainError, BeaconForkChoiceStore,
     BeaconSnapshot, CachedHead,
 };
+use attestation::SingleAttestation;
 use eth2::types::{EventKind, SseBlobSidecar, SseBlock, SseExtendedPayloadAttributes};
 use execution_layer::{
     BlockProposalContents, BlockProposalContentsType, BuilderParams, ChainHealth, ExecutionLayer,
@@ -2042,6 +2044,35 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
         )
     }
 
+    /// Accepts some `SingleAttestation` from the network and attempts to verify it, returning `Ok(_)` if
+    /// it is valid to be (re)broadcast on the gossip network.
+    pub fn verify_single_attestation_for_gossip(
+        &self,
+        single_attestation: &SingleAttestation,
+        subnet_id: Option<SubnetId>,
+    ) -> Result<SingleAttestationVerification, AttestationError> {
+        metrics::inc_counter(&metrics::UNAGGREGATED_ATTESTATION_PROCESSING_REQUESTS);
+        let _timer =
+            metrics::start_timer(&metrics::UNAGGREGATED_ATTESTATION_GOSSIP_VERIFICATION_TIMES);
+
+        let verify_attestation =
+            SingleAttestationVerification::verify(single_attestation, subnet_id, self)?;
+
+        // This method is called for API and gossip attestations, so this covers all unaggregated attestation events
+        if let Some(event_handler) = self.event_handler.as_ref() {
+            if event_handler.has_single_attestation_subscribers() {
+                // TODO(single-attestation) we should also emit the old attestation event?
+                event_handler.register(EventKind::SingleAttestation(Box::new(
+                    verify_attestation.single_attestation.clone(),
+                )));
+            }
+        }
+
+        metrics::inc_counter(&metrics::UNAGGREGATED_ATTESTATION_PROCESSING_SUCCESSES);
+
+        Ok(verify_attestation)
+    }
+
     /// Performs the same validation as `Self::verify_aggregated_attestation_for_gossip`, but for
     /// multiple attestations using batch BLS verification. Batch verification can provide
     /// significant CPU-time savings compared to individual verification.
@@ -2169,6 +2200,23 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
         })
     }
 
+    /// Accepts a `SingleATtestation` object and attempts to verify it in the context of fork
+    /// choice. If it is valid it is applied to `self.fork_choice`.
+    pub fn apply_single_attestation_to_fork_choice(
+        &self,
+        single_attestation: &SingleAttestation,
+    ) -> Result<(), Error> {
+        self.canonical_head
+            .fork_choice_write_lock()
+            .on_attestation(
+                self.slot()?,
+                single_attestation.data.clone(),
+                vec![single_attestation.attester_index as u64],
+                AttestationFromBlock::False,
+            )
+            .map_err(Into::into)
+    }
+
     /// Accepts some attestation-type object and attempts to verify it in the context of fork
     /// choice. If it is valid it is applied to `self.fork_choice`.
     ///
@@ -2178,13 +2226,15 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
     /// - `VerifiedAggregatedAttestation`
     pub fn apply_attestation_to_fork_choice(
         &self,
-        verified: &impl VerifiedAttestation<T>,
+        attestation_data: AttestationData,
+        attesting_indices: Vec<u64>,
     ) -> Result<(), Error> {
         self.canonical_head
             .fork_choice_write_lock()
             .on_attestation(
                 self.slot()?,
-                verified.indexed_attestation().to_ref(),
+                attestation_data,
+                attesting_indices,
                 AttestationFromBlock::False,
             )
             .map_err(Into::into)
@@ -2200,12 +2250,10 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
     /// and no error is returned.
     pub fn add_to_naive_aggregation_pool(
         &self,
-        unaggregated_attestation: &impl VerifiedAttestation<T>,
+        attestation: AttestationRef<T::EthSpec>,
     ) -> Result<(), AttestationError> {
         let _timer = metrics::start_timer(&metrics::ATTESTATION_PROCESSING_APPLY_TO_AGG_POOL);
 
-        let attestation = unaggregated_attestation.attestation();
-
         match self.naive_aggregation_pool.write().insert(attestation) {
             Ok(outcome) => trace!(
                 self.log,

beacon_node/beacon_chain/src/block_verification.rs

@@ -1655,7 +1655,8 @@ impl<T: BeaconChainTypes> ExecutionPendingBlock<T> {
 
             match fork_choice.on_attestation(
                 current_slot,
-                indexed_attestation,
+                indexed_attestation.data().clone(),
+                indexed_attestation.attesting_indices_to_vec(),
                 AttestationFromBlock::True,
             ) {
                 Ok(()) => Ok(()),

beacon_node/beacon_chain/src/events.rs

@@ -8,6 +8,7 @@ const DEFAULT_CHANNEL_CAPACITY: usize = 16;
 
 pub struct ServerSentEventHandler<E: EthSpec> {
     attestation_tx: Sender<EventKind<E>>,
+    single_attestation_tx: Sender<EventKind<E>>,
     block_tx: Sender<EventKind<E>>,
     blob_sidecar_tx: Sender<EventKind<E>>,
     finalized_tx: Sender<EventKind<E>>,
@@ -37,6 +38,7 @@ impl<E: EthSpec> ServerSentEventHandler<E> {
 
     pub fn new_with_capacity(log: Logger, capacity: usize) -> Self {
         let (attestation_tx, _) = broadcast::channel(capacity);
+        let (single_attestation_tx, _) = broadcast::channel(capacity);
         let (block_tx, _) = broadcast::channel(capacity);
         let (blob_sidecar_tx, _) = broadcast::channel(capacity);
         let (finalized_tx, _) = broadcast::channel(capacity);
@@ -56,6 +58,7 @@ impl<E: EthSpec> ServerSentEventHandler<E> {
 
         Self {
             attestation_tx,
+            single_attestation_tx,
             block_tx,
             blob_sidecar_tx,
             finalized_tx,
@@ -154,6 +157,10 @@ impl<E: EthSpec> ServerSentEventHandler<E> {
                 .block_gossip_tx
                 .send(kind)
                 .map(|count| log_count("block gossip", count)),
+            EventKind::SingleAttestation(_) => self
+                .single_attestation_tx
+                .send(kind)
+                .map(|count| log_count("single_attestation", count)),
         };
         if let Err(SendError(event)) = result {
             trace!(self.log, "No receivers registered to listen for event"; "event" => ?event);
@@ -164,6 +171,10 @@ impl<E: EthSpec> ServerSentEventHandler<E> {
         self.attestation_tx.subscribe()
     }
 
+    pub fn subscribe_single_attestation(&self) -> Receiver<EventKind<E>> {
+        self.single_attestation_tx.subscribe()
+    }
+
     pub fn subscribe_block(&self) -> Receiver<EventKind<E>> {
         self.block_tx.subscribe()
     }
@@ -232,6 +243,10 @@ impl<E: EthSpec> ServerSentEventHandler<E> {
         self.attestation_tx.receiver_count() > 0
     }
 
+    pub fn has_single_attestation_subscribers(&self) -> bool {
+        self.single_attestation_tx.receiver_count() > 0
+    }
+
     pub fn has_block_subscribers(&self) -> bool {
         self.block_tx.receiver_count() > 0
     }

beacon_node/beacon_chain/src/lib.rs

@@ -54,6 +54,7 @@ mod pre_finalization_cache;
 pub mod proposer_prep_service;
 pub mod schema_change;
 pub mod shuffling_cache;
+pub mod single_attestation_verification;
 pub mod state_advance_timer;
 pub mod sync_committee_rewards;
 pub mod sync_committee_verification;