# Nimbus # Copyright (c) 2023-2024 Status Research & Development GmbH # Licensed under either of # * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE)) # * MIT license ([LICENSE-MIT](LICENSE-MIT)) # at your option. # This file may not be copied, modified, or distributed except according to # those terms. import std/[typetraits], eth/common, results, ../web3_eth_conv, ../beacon_engine, web3/execution_types, ./api_utils, chronicles {.push gcsafe, raises:[CatchableError].} template validateVersion(attr, com, apiVersion) = let version = attr.version timestamp = ethTime attr.timestamp if apiVersion == Version.V3: if version != apiVersion: raise invalidAttr("forkChoiceUpdatedV3 expect PayloadAttributesV3" & " but got PayloadAttributes" & $version) if not com.isCancunOrLater(timestamp): raise unsupportedFork( "forkchoiceUpdatedV3 get invalid payloadAttributes timestamp") else: if com.isCancunOrLater(timestamp): if version < Version.V3: raise unsupportedFork("forkChoiceUpdated" & $apiVersion & " doesn't support payloadAttributes" & $version) if version > Version.V3: raise invalidAttr("forkChoiceUpdated" & $apiVersion & " doesn't support PayloadAttributes" & $version) elif com.isShanghaiOrLater(timestamp): if version < Version.V2: raise invalidParams("forkChoiceUpdated" & $apiVersion & " doesn't support payloadAttributesV1") if version > Version.V2: raise invalidAttr("if timestamp is Shanghai or later," & " payloadAttributes must be PayloadAttributesV2") else: if version != Version.V1: raise invalidParams("if timestamp is earlier than Shanghai," & " payloadAttributes must be PayloadAttributesV1") template validateHeaderTimestamp(header, com, apiVersion) = # See fCUV3 specification No.2 bullet iii # https://github.com/ethereum/execution-apis/blob/v1.0.0-beta.4/src/engine/cancun.md#specification-1 if com.isCancunOrLater(header.timestamp): if apiVersion != Version.V3: raise invalidAttr("forkChoiceUpdated" & $apiVersion & " doesn't support head block with timestamp >= Cancun") # See fCUV2 specification No.2 bullet 1 # https://github.com/ethereum/execution-apis/blob/v1.0.0-beta.4/src/engine/shanghai.md#specification-1 elif com.isShanghaiOrLater(header.timestamp): if apiVersion != Version.V2: raise invalidAttr("forkChoiceUpdated" & $apiVersion & " doesn't support head block with Shanghai timestamp") else: if apiVersion != Version.V1: raise invalidAttr("forkChoiceUpdated" & $apiVersion & " doesn't support head block with timestamp earlier than Shanghai") proc forkchoiceUpdated*(ben: BeaconEngineRef, apiVersion: Version, update: ForkchoiceStateV1, attrsOpt: Opt[PayloadAttributes]): ForkchoiceUpdatedResponse = let com = ben.com db = com.db chain = ben.chain blockHash = ethHash update.headBlockHash if blockHash == common.Hash256(): warn "Forkchoice requested update to zero hash" return simpleFCU(PayloadExecutionStatus.invalid) # Check whether we have the block yet in our database or not. If not, we'll # need to either trigger a sync, or to reject this forkchoice update for a # reason. let header = ben.chain.headerByHash(blockHash).valueOr: # If this block was previously invalidated, keep rejecting it here too let res = ben.checkInvalidAncestor(blockHash, blockHash) if res.isSome: return simpleFCU(res.get) # If the head hash is unknown (was not given to us in a newPayload request), # we cannot resolve the header, so not much to do. This could be extended in # the future to resolve from the `eth` network, but it's an unexpected case # that should be fixed, not papered over. var header: common.BlockHeader if not ben.get(blockHash, header): warn "Forkchoice requested unknown head", hash = blockHash.short return simpleFCU(PayloadExecutionStatus.syncing) # Header advertised via a past newPayload request. Start syncing to it. # Before we do however, make sure any legacy sync in switched off so we # don't accidentally have 2 cycles running. if not ben.ttdReached(): ben.reachTTD() # TODO: cancel downloader info "Forkchoice requested sync to new head", number = header.number, hash = blockHash.short # Update sync header (if any) com.syncReqNewHead(header) return simpleFCU(PayloadExecutionStatus.syncing) validateHeaderTimestamp(header, com, apiVersion) # Block is known locally, just sanity check that the beacon client does not # attempt to push us back to before the merge. # # Disable terminal PoW block conditions validation for fCUV2 and later. # https://github.com/ethereum/execution-apis/blob/v1.0.0-beta.4/src/engine/shanghai.md#specification-1 if apiVersion == Version.V1: let blockNumber = header.number if header.difficulty > 0.u256 or blockNumber == 0'u64: var td, ptd: DifficultyInt ttd = com.ttd.get(high(UInt256)) if not db.getTd(blockHash, td) or (blockNumber > 0'u64 and not db.getTd(header.parentHash, ptd)): error "TDs unavailable for TTD check", number = blockNumber, hash = blockHash.short, td = td, parent = header.parentHash.short, ptd = ptd return simpleFCU(PayloadExecutionStatus.invalid, "TDs unavailable for TTD check") if td < ttd or (blockNumber > 0'u64 and ptd > ttd): notice "Refusing beacon update to pre-merge", number = blockNumber, hash = blockHash.short, diff = header.difficulty, ptd = ptd, ttd = ttd return invalidFCU("Refusing beacon update to pre-merge") # If the head block is already in our canonical chain, the beacon client is # probably resyncing. Ignore the update. # See point 2 of fCUV1 specification # https://github.com/ethereum/execution-apis/blob/v1.0.0-beta.4/src/engine/paris.md#specification-1 var canonHash: common.Hash256 if db.getBlockHash(header.number, canonHash) and canonHash == blockHash: notice "Ignoring beacon update to old head", blockHash=blockHash.short, blockNumber=header.number return validFCU(Opt.none(PayloadID), blockHash) # If the beacon client also advertised a finalized block, mark the local # chain final and completely in PoS mode. let finalizedBlockHash = ethHash update.finalizedBlockHash if finalizedBlockHash != common.Hash256(): if not ben.posFinalized: ben.finalizePoS() if not ben.chain.isCanonical(finalizedBlockHash): warn "Final block not in canonical chain", hash=finalizedBlockHash.short raise invalidForkChoiceState("finalized block not canonical") db.finalizedHeaderHash(finalizedBlockHash) let safeBlockHash = ethHash update.safeBlockHash if safeBlockHash != common.Hash256(): if not ben.chain.isCanonical(safeBlockHash): warn "Safe block not in canonical chain", hash=safeBlockHash.short raise invalidForkChoiceState("safe head not canonical") db.safeHeaderHash(safeBlockHash) chain.forkChoice(finalizedBlockHash, blockHash).isOkOr: return invalidFCU(error, com, header) # If payload generation was requested, create a new block to be potentially # sealed by the beacon client. The payload will be requested later, and we # might replace it arbitrarilly many times in between. if attrsOpt.isSome: let attrs = attrsOpt.get() validateVersion(attrs, com, apiVersion) let bundle = ben.generatePayload(attrs).valueOr: error "Failed to create sealing payload", err = error raise invalidAttr(error) let id = computePayloadId(blockHash, attrs) ben.put(id, bundle.blockValue, bundle.executionPayload, bundle.blobsBundle) info "Created payload for sealing", id = id.toHex, hash = bundle.executionPayload.blockHash.short, number = bundle.executionPayload.blockNumber return validFCU(Opt.some(id), blockHash) return validFCU(Opt.none(PayloadID), blockHash)