@lodestar/beacon-node
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A Typescript implementation of the beacon chain
32 lines • 2.22 kB
JavaScript
import { assertLightClientServer } from "../../node/utils/lightclient.js";
import { GossipAction } from "../errors/index.js";
import { LightClientError, LightClientErrorCode } from "../errors/lightClientError.js";
import { updateReceivedTooEarly } from "./lightClientOptimisticUpdate.js";
// https://github.com/ethereum/consensus-specs/blob/dev/specs/altair/light-client/p2p-interface.md#light_client_finality_update
export function validateLightClientFinalityUpdate(config, chain, gossipedFinalityUpdate) {
assertLightClientServer(chain.lightClientServer);
// [IGNORE] No other finality_update with a lower or equal finalized_header.slot was already forwarded on the network
const gossipedFinalitySlot = gossipedFinalityUpdate.finalizedHeader.beacon.slot;
const localFinalityUpdate = chain.lightClientServer.getFinalityUpdate();
if (localFinalityUpdate && gossipedFinalitySlot <= localFinalityUpdate.finalizedHeader.beacon.slot) {
throw new LightClientError(GossipAction.IGNORE, {
code: LightClientErrorCode.FINALITY_UPDATE_ALREADY_FORWARDED,
});
}
// [IGNORE] The finality_update is received after the block at signature_slot was given enough time to propagate
// through the network -- i.e. validate that one-third of finality_update.signature_slot has transpired
// (SECONDS_PER_SLOT / INTERVALS_PER_SLOT seconds after the start of the slot, with a MAXIMUM_GOSSIP_CLOCK_DISPARITY allowance)
if (updateReceivedTooEarly(config, chain.genesisTime, gossipedFinalityUpdate)) {
throw new LightClientError(GossipAction.IGNORE, {
code: LightClientErrorCode.FINALITY_UPDATE_RECEIVED_TOO_EARLY,
});
}
// [IGNORE] The received finality_update matches the locally computed one exactly
const sszType = config.getPostAltairForkTypes(gossipedFinalityUpdate.attestedHeader.beacon.slot).LightClientFinalityUpdate;
if (localFinalityUpdate === null || !sszType.equals(gossipedFinalityUpdate, localFinalityUpdate)) {
throw new LightClientError(GossipAction.IGNORE, {
code: LightClientErrorCode.FINALITY_UPDATE_NOT_MATCHING_LOCAL,
});
}
}
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