# beacon_chain # Copyright (c) 2018-2022 Status Research & Development GmbH # Licensed and distributed under either of # * MIT license (license terms in the root directory or at https://opensource.org/licenses/MIT). # * Apache v2 license (license terms in the root directory or at https://www.apache.org/licenses/LICENSE-2.0). # at your option. This file may not be copied, modified, or distributed except according to those terms. {.push raises: [Defect].} import chronicles, stew/[assign2, results], ../spec/[beaconstate, forks, signatures, signatures_batch, state_transition], "."/[block_dag, blockchain_dag, blockchain_dag_light_client] export results, signatures_batch, block_dag, blockchain_dag # Clearance # --------------------------------------------- # # This module is in charge of making the # "quarantined" network blocks # pass the firewall and be stored in the chain DAG logScope: topics = "clearance" proc addResolvedHeadBlock( dag: ChainDAGRef, state: var ForkedHashedBeaconState, trustedBlock: ForkyTrustedSignedBeaconBlock, parent: BlockRef, cache: var StateCache, onBlockAdded: OnPhase0BlockAdded | OnAltairBlockAdded | OnBellatrixBlockAdded, stateDataDur, sigVerifyDur, stateVerifyDur: Duration ): BlockRef = doAssert state.matches_block_slot( trustedBlock.root, trustedBlock.message.slot), "Given state must have the new block applied" let blockRoot = trustedBlock.root blockRef = BlockRef.init(blockRoot, trustedBlock.message) startTick = Moment.now() link(parent, blockRef) dag.forkBlocks.incl(KeyedBlockRef.init(blockRef)) # Resolved blocks should be stored in database dag.putBlock(trustedBlock) let putBlockTick = Moment.now() var foundHead: bool for head in dag.heads.mitems(): if head.isAncestorOf(blockRef): head = blockRef foundHead = true break if not foundHead: dag.heads.add(blockRef) # Regardless of the chain we're on, the deposits come in the same order so # as soon as we import a block, we'll also update the shared public key # cache dag.updateValidatorKeys(getStateField(state, validators).asSeq()) # Getting epochRef with the state will potentially create a new EpochRef let epochRef = dag.getEpochRef(state, cache) epochRefTick = Moment.now() debug "Block resolved", blockRoot = shortLog(blockRoot), blck = shortLog(trustedBlock.message), heads = dag.heads.len(), stateDataDur, sigVerifyDur, stateVerifyDur, putBlockDur = putBlockTick - startTick, epochRefDur = epochRefTick - putBlockTick # Update light client data dag.processNewBlockForLightClient(state, trustedBlock, parent.bid) # Notify others of the new block before processing the quarantine, such that # notifications for parents happens before those of the children if onBlockAdded != nil: onBlockAdded(blockRef, trustedBlock, epochRef) if not(isNil(dag.onBlockAdded)): dag.onBlockAdded(ForkedTrustedSignedBeaconBlock.init(trustedBlock)) blockRef proc checkStateTransition( dag: ChainDAGRef, signedBlock: ForkySigVerifiedSignedBeaconBlock, cache: var StateCache): Result[void, BlockError] = ## Ensure block can be applied on a state func restore(v: var ForkedHashedBeaconState) = assign(dag.clearanceState, dag.headState) let res = state_transition_block( dag.cfg, dag.clearanceState, signedBlock, cache, dag.updateFlags, restore) if res.isErr(): info "Invalid block", blockRoot = shortLog(signedBlock.root), blck = shortLog(signedBlock.message), error = res.error() err(BlockError.Invalid) else: ok() proc advanceClearanceState*(dag: ChainDAGRef) = # When the chain is synced, the most likely block to be produced is the block # right after head - we can exploit this assumption and advance the state # to that slot before the block arrives, thus allowing us to do the expensive # epoch transition ahead of time. # Notably, we use the clearance state here because that's where the block will # first be seen - later, this state will be copied to the head state! let advanced = withState(dag.clearanceState): state.data.slot > state.data.latest_block_header.slot if not advanced: let next = getStateField(dag.clearanceState, slot) + 1 let startTick = Moment.now() var cache = StateCache() info = ForkedEpochInfo() dag.advanceSlots(dag.clearanceState, next, true, cache, info) debug "Prepared clearance state for next block", next, updateStateDur = Moment.now() - startTick proc addHeadBlock*( dag: ChainDAGRef, verifier: var BatchVerifier, signedBlock: ForkySignedBeaconBlock, onBlockAdded: OnPhase0BlockAdded | OnAltairBlockAdded | OnBellatrixBlockAdded ): Result[BlockRef, BlockError] = ## Try adding a block to the chain, verifying first that it passes the state ## transition function and contains correct cryptographic signature. ## ## Cryptographic checks can be skipped by adding skipBLSValidation to ## dag.updateFlags logScope: blockRoot = shortLog(signedBlock.root) blck = shortLog(signedBlock.message) signature = shortLog(signedBlock.signature) template blck(): untyped = signedBlock.message # shortcuts without copy template blockRoot(): untyped = signedBlock.root # If the block we get is older than what we finalized already, we drop it. # One way this can happen is that we start request a block and finalization # happens in the meantime - the block we requested will then be stale # by the time it gets here. if blck.slot <= dag.finalizedHead.slot: let existing = dag.getBlockIdAtSlot(blck.slot) # The exact slot match ensures we reject blocks that were orphaned in # the finalized chain if existing.isSome: if existing.get().bid.slot == blck.slot and existing.get().bid.root == blockRoot: debug "Duplicate block" return err(BlockError.Duplicate) # Block is older than finalized, but different from the block in our # canonical history: it must be from an unviable branch debug "Block from unviable fork", existing = shortLog(existing.get()), finalizedHead = shortLog(dag.finalizedHead), tail = shortLog(dag.tail) return err(BlockError.UnviableFork) # Check non-finalized blocks as well if dag.containsForkBlock(blockRoot): return err(BlockError.Duplicate) let parent = dag.getBlockRef(blck.parent_root).valueOr: # There are two cases where the parent won't be found: we don't have it or # it has been finalized already, and as a result the branch the new block # is on is no longer a viable fork candidate - we can't tell which is which # at this stage, but we can check if we've seen the parent block previously # and thus prevent requests for it to be downloaded again. let parentId = dag.getBlockId(blck.parent_root) if parentId.isSome(): debug "Block unviable due to pre-finalized-checkpoint parent", parentId = parentId.get() return err(BlockError.UnviableFork) debug "Block parent unknown or finalized already", parentId return err(BlockError.MissingParent) if parent.slot >= blck.slot: # A block whose parent is newer than the block itself is clearly invalid - # discard it immediately debug "Block older than parent", parent = shortLog(parent) return err(BlockError.Invalid) # The block is resolved, now it's time to validate it to ensure that the # blocks we add to the database are clean for the given state let startTick = Moment.now() # The clearance state works as the canonical # "let's make things permanent" point and saves things to the database - # storing things is slow, so we don't want to do so before there's a # reasonable chance that the information will become more permanently useful - # by the time a new block reaches this point, the parent block will already # have "established" itself in the network to some degree at least. var cache = StateCache() # We've verified that the slot of the new block is newer than that of the # parent, so we should now be able to create an approriate clearance state # onto which we can apply the new block let clearanceBlock = BlockSlotId.init(parent.bid, signedBlock.message.slot) if not updateState( dag, dag.clearanceState, clearanceBlock, true, cache): # We should never end up here - the parent must be a block no older than and # rooted in the finalized checkpoint, hence we should always be able to # load its corresponding state error "Unable to load clearance state for parent block, database corrupt?", clearanceBlock = shortLog(clearanceBlock) return err(BlockError.MissingParent) let stateDataTick = Moment.now() # First, batch-verify all signatures in block if skipBLSValidation notin dag.updateFlags: # TODO: remove skipBLSValidation var sigs: seq[SignatureSet] if (let e = sigs.collectSignatureSets( signedBlock, dag.db.immutableValidators, dag.clearanceState, cache); e.isErr()): # A PublicKey or Signature isn't on the BLS12-381 curve info "Unable to load signature sets", err = e.error() return err(BlockError.Invalid) if not verifier.batchVerify(sigs): info "Block signature verification failed", signature = shortLog(signedBlock.signature) return err(BlockError.Invalid) let sigVerifyTick = Moment.now() ? checkStateTransition(dag, signedBlock.asSigVerified(), cache) let stateVerifyTick = Moment.now() # Careful, clearanceState.data has been updated but not blck - we need to # create the BlockRef first! ok addResolvedHeadBlock( dag, dag.clearanceState, signedBlock.asTrusted(), parent, cache, onBlockAdded, stateDataDur = stateDataTick - startTick, sigVerifyDur = sigVerifyTick - stateDataTick, stateVerifyDur = stateVerifyTick - sigVerifyTick) proc addBackfillBlock*( dag: ChainDAGRef, signedBlock: ForkySignedBeaconBlock): Result[void, BlockError] = ## When performing checkpoint sync, we need to backfill historical blocks ## in order to respond to GetBlocksByRange requests. Backfill blocks are ## added in backwards order, one by one, based on the `parent_root` of the ## earliest block we know about. ## ## Because only one history is relevant when backfilling, one doesn't have to ## consider forks or other finalization-related issues - a block is either ## valid and finalized, or not. logScope: blockRoot = shortLog(signedBlock.root) blck = shortLog(signedBlock.message) signature = shortLog(signedBlock.signature) backfill = (dag.backfill.slot, shortLog(dag.backfill.parent_root)) template blck(): untyped = signedBlock.message # shortcuts without copy template blockRoot(): untyped = signedBlock.root let startTick = Moment.now() if blck.slot >= dag.backfill.slot: let existing = dag.getBlockIdAtSlot(blck.slot) if existing.isSome: if existing.get().bid.slot == blck.slot and existing.get().bid.root == blockRoot: # We should not call the block added callback for blocks that already # existed in the pool, as that may confuse consumers such as the fork # choice. debug "Duplicate block" return err(BlockError.Duplicate) # Block is older than finalized, but different from the block in our # canonical history: it must be from an unviable branch debug "Block from unviable fork", existing = shortLog(existing.get()), finalizedHead = shortLog(dag.finalizedHead) return err(BlockError.UnviableFork) if blck.slot == dag.frontfill.slot and dag.backfill.parent_root == dag.frontfill.root: if blockRoot != dag.frontfill.root: # We've matched the backfill blocks all the way back to frontfill via the # `parent_root` chain and ended up at a different block - one way this # can happen is when an invalid `--network` parameter is given during # startup (though in theory, we check that - maybe the database was # swapped or something?). fatal "Checkpoint given during initial startup inconsistent with genesis block - wrong network used when starting the node?", genesis = shortLog(dag.genesis), tail = shortLog(dag.tail), head = shortLog(dag.head) quit 1 dag.backfill = blck.toBeaconBlockSummary() dag.db.finalizedBlocks.insert(blck.slot, blockRoot) dag.updateFrontfillBlocks() notice "Received final block during backfill, backfill complete" # Backfill done - dag.backfill.slot now points to genesis block just like # it would if we loaded a fully synced database - returning duplicate # here is appropriate, though one could also call it ... ok? return err(BlockError.Duplicate) if dag.backfill.parent_root != blockRoot: debug "Block does not match expected backfill root" return err(BlockError.MissingParent) # MissingChild really, but .. # If the hash is correct, the block itself must be correct, but the root does # not cover the signature, which we check next let proposerKey = dag.validatorKey(blck.proposer_index) if proposerKey.isNone(): # We've verified that the block root matches our expectations by following # the chain of parents all the way from checkpoint. If all those blocks # were valid, the proposer_index in this block must also be valid, and we # should have a key for it but we don't: this is either a bug on our from # which we cannot recover, or an invalid checkpoint state was given in which # case we're in trouble. fatal "Invalid proposer in backfill block - checkpoint state corrupt?", head = shortLog(dag.head), tail = shortLog(dag.tail), genesis = shortLog(dag.genesis) quit 1 if not verify_block_signature( dag.forkAtEpoch(blck.slot.epoch), getStateField(dag.headState, genesis_validators_root), blck.slot, signedBlock.root, proposerKey.get(), signedBlock.signature): info "Block signature verification failed" return err(BlockError.Invalid) let sigVerifyTick = Moment.now dag.putBlock(signedBlock.asTrusted()) dag.db.finalizedBlocks.insert(blck.slot, blockRoot) dag.backfill = blck.toBeaconBlockSummary() let putBlockTick = Moment.now debug "Block backfilled", sigVerifyDur = sigVerifyTick - startTick, putBlockDur = putBlocktick - sigVerifyTick ok()