Verify KZG in Bulk During Block Sync (#4903)

beacon_node/beacon_chain/src/block_verification.rs

@@ -583,29 +583,33 @@ pub fn signature_verify_chain_segment<T: BeaconChainTypes>(
         &chain.spec,
     )?;
 
+    // unzip chain segment and verify kzg in bulk
+    let (roots, blocks): (Vec<_>, Vec<_>) = chain_segment.into_iter().unzip();
+    let maybe_available_blocks = chain
+        .data_availability_checker
+        .verify_kzg_for_rpc_blocks(blocks)?;
+    // zip it back up
+    let mut signature_verified_blocks = roots
+        .into_iter()
+        .zip(maybe_available_blocks)
+        .map(|(block_root, maybe_available_block)| {
+            let consensus_context = ConsensusContext::new(maybe_available_block.slot())
+                .set_current_block_root(block_root);
+            SignatureVerifiedBlock {
+                block: maybe_available_block,
+                block_root,
+                parent: None,
+                consensus_context,
+            }
+        })
+        .collect::<Vec<_>>();
+
+    // verify signatures
     let pubkey_cache = get_validator_pubkey_cache(chain)?;
     let mut signature_verifier = get_signature_verifier(&state, &pubkey_cache, &chain.spec);
-
-    let mut signature_verified_blocks = Vec::with_capacity(chain_segment.len());
-
-    for (block_root, block) in &chain_segment {
-        let mut consensus_context =
-            ConsensusContext::new(block.slot()).set_current_block_root(*block_root);
-
-        signature_verifier.include_all_signatures(block.as_block(), &mut consensus_context)?;
-
-        let maybe_available_block = chain
-            .data_availability_checker
-            .check_rpc_block_availability(block.clone())?;
-
-        // Save the block and its consensus context. The context will have had its proposer index
-        // and attesting indices filled in, which can be used to accelerate later block processing.
-        signature_verified_blocks.push(SignatureVerifiedBlock {
-            block: maybe_available_block,
-            block_root: *block_root,
-            parent: None,
-            consensus_context,
-        });
+    for svb in &mut signature_verified_blocks {
+        signature_verifier
+            .include_all_signatures(svb.block.as_block(), &mut svb.consensus_context)?;
     }
 
     if signature_verifier.verify().is_err() {
@@ -1159,10 +1163,7 @@ impl<T: BeaconChainTypes> IntoExecutionPendingBlock<T> for Arc<SignedBeaconBlock
             .map_err(|e| BlockSlashInfo::SignatureNotChecked(self.signed_block_header(), e))?;
         let maybe_available = chain
             .data_availability_checker
-            .check_rpc_block_availability(RpcBlock::new_without_blobs(
-                Some(block_root),
-                self.clone(),
-            ))
+            .verify_kzg_for_rpc_block(RpcBlock::new_without_blobs(Some(block_root), self.clone()))
             .map_err(|e| {
                 BlockSlashInfo::SignatureNotChecked(
                     self.signed_block_header(),
@@ -1192,7 +1193,7 @@ impl<T: BeaconChainTypes> IntoExecutionPendingBlock<T> for RpcBlock<T::EthSpec>
             .map_err(|e| BlockSlashInfo::SignatureNotChecked(self.signed_block_header(), e))?;
         let maybe_available = chain
             .data_availability_checker
-            .check_rpc_block_availability(self.clone())
+            .verify_kzg_for_rpc_block(self.clone())
             .map_err(|e| {
                 BlockSlashInfo::SignatureNotChecked(
                     self.signed_block_header(),

beacon_node/beacon_chain/src/block_verification_types.rs

@@ -45,6 +45,13 @@ impl<E: EthSpec> RpcBlock<E> {
             RpcBlockInner::BlockAndBlobs(block, _) => block,
         }
     }
+
+    pub fn blobs(&self) -> Option<&BlobSidecarList<E>> {
+        match &self.block {
+            RpcBlockInner::Block(_) => None,
+            RpcBlockInner::BlockAndBlobs(_, blobs) => Some(blobs),
+        }
+    }
 }
 
 /// Note: This variant is intentionally private because we want to safely construct the

beacon_node/beacon_chain/src/data_availability_checker.rs

@@ -240,9 +240,12 @@ impl<T: BeaconChainTypes> DataAvailabilityChecker<T> {
             .put_pending_executed_block(executed_block)
     }
 
-    /// Checks if a block is available, returns a `MaybeAvailableBlock` that may include the fully
-    /// available block.
-    pub fn check_rpc_block_availability(
+    /// Verifies kzg commitments for an RpcBlock, returns a `MaybeAvailableBlock` that may
+    /// include the fully available block.
+    ///
+    /// WARNING: This function assumes all required blobs are already present, it does NOT
+    ///          check if there are any missing blobs.
+    pub fn verify_kzg_for_rpc_block(
         &self,
         block: RpcBlock<T::EthSpec>,
     ) -> Result<MaybeAvailableBlock<T::EthSpec>, AvailabilityCheckError> {
@@ -279,6 +282,68 @@ impl<T: BeaconChainTypes> DataAvailabilityChecker<T> {
         }
     }
 
+    /// Checks if a vector of blocks are available. Returns a vector of `MaybeAvailableBlock`
+    /// This is more efficient than calling `verify_kzg_for_rpc_block` in a loop as it does
+    /// all kzg verification at once
+    ///
+    /// WARNING: This function assumes all required blobs are already present, it does NOT
+    ///          check if there are any missing blobs.
+    pub fn verify_kzg_for_rpc_blocks(
+        &self,
+        blocks: Vec<RpcBlock<T::EthSpec>>,
+    ) -> Result<Vec<MaybeAvailableBlock<T::EthSpec>>, AvailabilityCheckError> {
+        let mut results = Vec::with_capacity(blocks.len());
+        let all_blobs: BlobSidecarList<T::EthSpec> = blocks
+            .iter()
+            .filter(|block| self.blobs_required_for_block(block.as_block()))
+            // this clone is cheap as it's cloning an Arc
+            .filter_map(|block| block.blobs().cloned())
+            .flatten()
+            .collect::<Vec<_>>()
+            .into();
+
+        // verify kzg for all blobs at once
+        if !all_blobs.is_empty() {
+            let kzg = self
+                .kzg
+                .as_ref()
+                .ok_or(AvailabilityCheckError::KzgNotInitialized)?;
+            verify_kzg_for_blob_list(&all_blobs, kzg)?;
+        }
+
+        for block in blocks {
+            let (block_root, block, blobs) = block.deconstruct();
+            match blobs {
+                None => {
+                    if self.blobs_required_for_block(&block) {
+                        results.push(MaybeAvailableBlock::AvailabilityPending { block_root, block })
+                    } else {
+                        results.push(MaybeAvailableBlock::Available(AvailableBlock {
+                            block_root,
+                            block,
+                            blobs: None,
+                        }))
+                    }
+                }
+                Some(blob_list) => {
+                    let verified_blobs = if self.blobs_required_for_block(&block) {
+                        Some(blob_list)
+                    } else {
+                        None
+                    };
+                    // already verified kzg for all blobs
+                    results.push(MaybeAvailableBlock::Available(AvailableBlock {
+                        block_root,
+                        block,
+                        blobs: verified_blobs,
+                    }))
+                }
+            }
+        }
+
+        Ok(results)
+    }
+
     /// Determines the blob requirements for a block. If the block is pre-deneb, no blobs are required.
     /// If the block's epoch is from prior to the data availability boundary, no blobs are required.
     fn blobs_required_for_block(&self, block: &SignedBeaconBlock<T::EthSpec>) -> bool {

beacon_node/beacon_chain/tests/attestation_production.rs

@@ -140,7 +140,7 @@ async fn produces_attestations() {
                 available_block,
             ) = chain
                 .data_availability_checker
-                .check_rpc_block_availability(rpc_block)
+                .verify_kzg_for_rpc_block(rpc_block)
                 .unwrap()
             else {
                 panic!("block should be available")
@@ -218,7 +218,7 @@ async fn early_attester_cache_old_request() {
         harness
             .chain
             .data_availability_checker
-            .check_rpc_block_availability(rpc_block)
+            .verify_kzg_for_rpc_block(rpc_block)
             .unwrap()
     else {
         panic!("block should be available")

beacon_node/beacon_chain/tests/store_tests.rs

@@ -2464,10 +2464,10 @@ async fn weak_subjectivity_sync_test(slots: Vec<Slot>, checkpoint_slot: Slot) {
         if let MaybeAvailableBlock::Available(block) = harness
             .chain
             .data_availability_checker
-            .check_rpc_block_availability(
+            .verify_kzg_for_rpc_block(
                 RpcBlock::new(Some(block_root), Arc::new(full_block), Some(blobs)).unwrap(),
             )
-            .expect("should check availability")
+            .expect("should verify kzg")
         {
             available_blocks.push(block);
         }

beacon_node/network/src/network_beacon_processor/sync_methods.rs

@@ -560,14 +560,10 @@ impl<T: BeaconChainTypes> NetworkBeaconProcessor<T> {
         downloaded_blocks: Vec<RpcBlock<T::EthSpec>>,
     ) -> (usize, Result<(), ChainSegmentFailed>) {
         let total_blocks = downloaded_blocks.len();
-        let available_blocks = match downloaded_blocks
-            .into_iter()
-            .map(|block| {
-                self.chain
-                    .data_availability_checker
-                    .check_rpc_block_availability(block)
-            })
-            .collect::<Result<Vec<_>, _>>()
+        let available_blocks = match self
+            .chain
+            .data_availability_checker
+            .verify_kzg_for_rpc_blocks(downloaded_blocks)
         {
             Ok(blocks) => blocks
                 .into_iter()