fix: do not download known block by root

packages/beacon-node/src/chain/chain.ts

@@ -301,6 +301,10 @@ export class BeaconChain implements IBeaconChain {
     await this.bls.close();
   }
 
+  seenBlock(blockRoot: RootHex): boolean {
+    return this.seenGossipBlockInput.hasBlock(blockRoot) || this.forkChoice.hasBlockHex(blockRoot);
+  }
+
   regenCanAcceptWork(): boolean {
     return this.regen.canAcceptWork();
   }

packages/beacon-node/src/chain/interface.ts

@@ -119,6 +119,8 @@ export interface IBeaconChain {
 
   /** Stop beacon chain processing */
   close(): Promise<void>;
+  /** Chain has seen the specified block root or not. The block may not be processed yet, use forkchoice.hasBlock to check it  */
+  seenBlock(blockRoot: RootHex): boolean;
   /** Populate in-memory caches with persisted data. Call at least once on startup */
   loadFromDisk(): Promise<void>;
   /** Persist in-memory data to the DB. Call at least once before stopping the process */

packages/beacon-node/src/chain/seenCache/seenGossipBlockInput.ts

@@ -2,7 +2,7 @@ import {toHexString} from "@chainsafe/ssz";
 import {deneb, RootHex, ssz, allForks} from "@lodestar/types";
 import {ChainForkConfig} from "@lodestar/config";
 import {pruneSetToMax} from "@lodestar/utils";
-import {BLOBSIDECAR_FIXED_SIZE} from "@lodestar/params";
+import {BLOBSIDECAR_FIXED_SIZE, ForkSeq} from "@lodestar/params";
 
 import {
   BlockInput,
@@ -29,9 +29,11 @@ type BlockInputCacheType = {
 const MAX_GOSSIPINPUT_CACHE = 5;
 
 /**
- * SeenGossipBlockInput tracks and caches the live blobs and blocks on the network to solve data availability
- * for the blockInput. If no block has been seen yet for some already seen blobs, it responds will null, but
- * on the first block or the consequent blobs it responds with blobs promise till all blobs become available.
+ * For predeneb, SeenGossipBlockInput only tracks and caches block so that we don't need to download known block
+ * roots. From deneb, it serves same purpose plus tracks and caches the live blobs and blocks on the network to
+ * solve data availability for the blockInput. If no block has been seen yet for some already seen blobs, it
+ * responds will null, but on the first block or the consequent blobs it responds with blobs promise till all blobs
+ * become available.
  *
  * One can start processing block on blobs promise blockInput response and can await on the promise before
  * fully importing the block. The blobs promise is gets resolved as soon as all blobs corresponding to that
@@ -44,6 +46,10 @@ export class SeenGossipBlockInput {
     pruneSetToMax(this.blockInputCache, MAX_GOSSIPINPUT_CACHE);
   }
 
+  hasBlock(blockRoot: RootHex): boolean {
+    return this.blockInputCache.has(blockRoot);
+  }
+
   getGossipBlockInput(
     config: ChainForkConfig,
     gossipedInput: GossipedBlockInput
@@ -83,9 +89,16 @@ export class SeenGossipBlockInput {
     if (!this.blockInputCache.has(blockHex)) {
       this.blockInputCache.set(blockHex, blockCache);
     }
+
     const {block: signedBlock, blockBytes, blobsCache, availabilityPromise, resolveAvailability} = blockCache;
 
     if (signedBlock !== undefined) {
+      if (config.getForkSeq(signedBlock.message.slot) < ForkSeq.deneb) {
+        return {
+          blockInput: getBlockInput.preDeneb(config, signedBlock, BlockSource.gossip, blockBytes ?? null),
+          blockInputMeta: {pending: null, haveBlobs: 0, expectedBlobs: 0},
+        };
+      }
       // block is available, check if all blobs have shown up
       const {slot, body} = signedBlock.message;
       const {blobKzgCommitments} = body as deneb.BeaconBlockBody;

packages/beacon-node/src/network/processor/gossipHandlers.ts

@@ -45,13 +45,7 @@ import {PeerAction} from "../peers/index.js";
 import {validateLightClientFinalityUpdate} from "../../chain/validation/lightClientFinalityUpdate.js";
 import {validateLightClientOptimisticUpdate} from "../../chain/validation/lightClientOptimisticUpdate.js";
 import {validateGossipBlobSidecar} from "../../chain/validation/blobSidecar.js";
-import {
-  BlockInput,
-  BlockSource,
-  getBlockInput,
-  GossipedInputType,
-  BlobSidecarValidation,
-} from "../../chain/blocks/types.js";
+import {BlockInput, GossipedInputType, BlobSidecarValidation} from "../../chain/blocks/types.js";
 import {sszDeserialize} from "../gossip/topic.js";
 import {INetworkCore} from "../core/index.js";
 import {INetwork} from "../interface.js";
@@ -123,28 +117,21 @@ function getDefaultHandlers(modules: ValidatorFnsModules, options: GossipHandler
     const delaySec = chain.clock.secFromSlot(slot, seenTimestampSec);
     const recvToVal = Date.now() / 1000 - seenTimestampSec;
 
-    let blockInput;
-    let blockInputMeta;
-    if (config.getForkSeq(signedBlock.message.slot) >= ForkSeq.deneb) {
-      const blockInputRes = chain.seenGossipBlockInput.getGossipBlockInput(config, {
-        type: GossipedInputType.block,
-        signedBlock,
-        blockBytes,
-      });
-
-      blockInput = blockInputRes.blockInput;
-      blockInputMeta = blockInputRes.blockInputMeta;
-
-      // blockInput can't be returned null, improve by enforcing via return types
-      if (blockInput === null) {
-        throw Error(
-          `Invalid null blockInput returned by getGossipBlockInput for type=${GossipedInputType.block} blockHex=${blockHex} slot=${slot}`
-        );
-      }
-    } else {
-      blockInput = getBlockInput.preDeneb(config, signedBlock, BlockSource.gossip, blockBytes);
-      blockInputMeta = {};
+    // always set block to seen cache for all forks so that we don't need to download it
+    const blockInputRes = chain.seenGossipBlockInput.getGossipBlockInput(config, {
+      type: GossipedInputType.block,
+      signedBlock,
+      blockBytes,
+    });
+    const blockInput = blockInputRes.blockInput;
+    // blockInput can't be returned null, improve by enforcing via return types
+    if (blockInput === null) {
+      throw Error(
+        `Invalid null blockInput returned by getGossipBlockInput for type=${GossipedInputType.block} blockHex=${blockHex} slot=${slot}`
+      );
     }
+    const blockInputMeta =
+      config.getForkSeq(signedBlock.message.slot) >= ForkSeq.deneb ? blockInputRes.blockInputMeta : {};
 
     metrics?.gossipBlock.receivedToGossipValidate.observe(recvToVal);
     logger.verbose("Received gossip block", {

packages/beacon-node/src/network/processor/index.ts

@@ -231,11 +231,12 @@ export class NetworkProcessor {
   }
 
   searchUnknownSlotRoot({slot, root}: SlotRootHex, peer?: PeerIdStr): void {
-    // Search for the unknown block
-    if (!this.unknownRootsBySlot.getOrDefault(slot).has(root)) {
-      this.unknownRootsBySlot.getOrDefault(slot).add(root);
-      this.events.emit(NetworkEvent.unknownBlock, {rootHex: root, peer});
+    if (this.chain.seenBlock(root) || this.unknownRootsBySlot.getOrDefault(slot).has(root)) {
+      return;
     }
+    // Search for the unknown block
+    this.unknownRootsBySlot.getOrDefault(slot).add(root);
+    this.events.emit(NetworkEvent.unknownBlock, {rootHex: root, peer});
   }
 
   private onPendingGossipsubMessage(message: PendingGossipsubMessage): void {