feat: assert fork digest to match our current fork (#7950)

Currently we only check if the incoming peer's ENR's fork digest is
known by ours. As long as it matches one of the fork digest, it will
pass our check.

This PR asserts the fork digest must be of our current fork.

---------

Co-authored-by: Nazar Hussain <nazarhussain@gmail.com>

Author: ensi321

packages/beacon-node/src/network/discv5/index.ts

@@ -14,6 +14,7 @@ export type Discv5Opts = {
   discv5: LodestarDiscv5Opts;
   logger: LoggerNode;
   config: BeaconConfig;
+  genesisTime: number;
   metrics?: NetworkCoreMetrics;
 };
 
@@ -48,6 +49,7 @@ export class Discv5Worker extends (EventEmitter as {new (): StrictEventEmitter<E
       chainConfig: chainConfigFromJson(chainConfigToJson(opts.config)),
       genesisValidatorsRoot: opts.config.genesisValidatorsRoot,
       loggerOpts: opts.logger.toOpts(),
+      genesisTime: opts.genesisTime,
     };
     const worker = new Worker("./worker.js", {workerData} as ConstructorParameters<typeof Worker>[1]);
 

packages/beacon-node/src/network/discv5/types.ts

@@ -39,6 +39,7 @@ export interface Discv5WorkerData {
   chainConfig: ChainConfig;
   genesisValidatorsRoot: Uint8Array;
   loggerOpts: LoggerNodeOpts;
+  genesisTime: number;
 }
 
 /**

packages/beacon-node/src/network/discv5/utils.ts

@@ -1,16 +1,19 @@
 import {ENR} from "@chainsafe/enr";
 import {BeaconConfig} from "@lodestar/config";
+import {MAXIMUM_GOSSIP_CLOCK_DISPARITY} from "../../constants/constants.js";
+import {IClock} from "../../util/clock.js";
 import {ENRKey} from "../metadata.js";
 
 export enum ENRRelevance {
   no_tcp = "no_tcp",
   no_eth2 = "no_eth2",
   // biome-ignore lint/style/useNamingConvention: Need to use the this name for network convention
   unknown_forkDigest = "unknown_forkDigest",
+  current_fork_mismatch = "current_fork_mismatch",
   relevant = "relevant",
 }
 
-export function enrRelevance(enr: ENR, config: BeaconConfig): ENRRelevance {
+export function enrRelevance(enr: ENR, config: BeaconConfig, clock: IClock): ENRRelevance {
   // We are not interested in peers that don't advertise their tcp addr
   const multiaddrTCP = enr.getLocationMultiaddr(ENRKey.tcp);
   if (!multiaddrTCP) {
@@ -31,7 +34,16 @@ export function enrRelevance(enr: ENR, config: BeaconConfig): ENRRelevance {
     return ENRRelevance.unknown_forkDigest;
   }
 
-  // TODO: Then check if the next fork info matches ours
+  // Check if fork digest's fork matches ours
+  const currentSlot = clock.slotWithFutureTolerance(MAXIMUM_GOSSIP_CLOCK_DISPARITY);
+  const localForkInfo = config.getForkInfo(currentSlot);
+  // We only connect if the ENR's fork matches our current fork.
+  // We also allow it to be the previous fork due to delay and infrequent update of DHT.
+  if (forkName !== localForkInfo.name && forkName !== localForkInfo.prevForkName) {
+    return ENRRelevance.current_fork_mismatch;
+  }
+
+  // TODO: If we have next fork scheduled, check if next fork info matches ours
   // const enrForkId = ssz.phase0.ENRForkID.deserialize(eth2);
 
   return ENRRelevance.relevant;

packages/beacon-node/src/network/discv5/worker.ts

@@ -13,6 +13,7 @@ import {Gauge} from "@lodestar/utils";
 import {Multiaddr, multiaddr} from "@multiformats/multiaddr";
 import {RegistryMetricCreator} from "../../metrics/index.js";
 import {collectNodeJSMetrics} from "../../metrics/nodeJsMetrics.js";
+import {Clock} from "../../util/clock.js";
 import {profileNodeJS, writeHeapSnapshot} from "../../util/profile.js";
 import {Discv5WorkerApi, Discv5WorkerData} from "./types.js";
 import {ENRRelevance, enrRelevance} from "./utils.js";
@@ -68,8 +69,12 @@ for (const bootEnr of workerData.bootEnrs) {
 /** Used to push discovered ENRs */
 const subject = new Subject<ENRData>();
 
+/** Define a new clock */
+const abortController = new AbortController();
+const clock = new Clock({config, genesisTime: workerData.genesisTime, signal: abortController.signal});
+
 const onDiscovered = (enr: ENR): void => {
-  const status = enrRelevance(enr, config);
+  const status = enrRelevance(enr, config, clock);
   enrRelevanceMetric?.inc({status});
   if (status === ENRRelevance.relevant) {
     subject.next(enr.toObject());

packages/beacon-node/src/network/peers/discover.ts

@@ -6,6 +6,7 @@ import {ATTESTATION_SUBNET_COUNT, SYNC_COMMITTEE_SUBNET_COUNT} from "@lodestar/p
 import {SubnetID} from "@lodestar/types";
 import {pruneSetToMax, sleep} from "@lodestar/utils";
 import {Multiaddr} from "@multiformats/multiaddr";
+import {IClock} from "../../util/clock.js";
 import {NetworkCoreMetrics} from "../core/metrics.js";
 import {Discv5Worker} from "../discv5/index.js";
 import {LodestarDiscv5Opts} from "../discv5/types.js";
@@ -30,6 +31,7 @@ export type PeerDiscoveryOpts = {
 export type PeerDiscoveryModules = {
   privateKey: PrivateKey;
   libp2p: Libp2p;
+  clock: IClock;
   peerRpcScores: IPeerRpcScoreStore;
   metrics: NetworkCoreMetrics | null;
   logger: LoggerNode;
@@ -165,6 +167,7 @@ export class PeerDiscovery {
       metrics: modules.metrics ?? undefined,
       logger: modules.logger,
       config: modules.config,
+      genesisTime: modules.clock.genesisTime,
     });
 
     return new PeerDiscovery(modules, opts, discv5);