330 lines
13 KiB
Nim
330 lines
13 KiB
Nim
# beacon_chain
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# Copyright (c) 2018-2021 Status Research & Development GmbH
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# Licensed and distributed under either of
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# * MIT license (license terms in the root directory or at https://opensource.org/licenses/MIT).
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# * Apache v2 license (license terms in the root directory or at https://www.apache.org/licenses/LICENSE-2.0).
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# at your option. This file may not be copied, modified, or distributed except according to those terms.
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{.push raises: [Defect].}
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import
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std/tables,
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chronicles,
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stew/[assign2, results],
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eth/keys,
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../extras, ../beacon_clock,
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../spec/[crypto, datatypes, digest, helpers, signatures, signatures_batch, state_transition],
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./block_pools_types, ./blockchain_dag, ./block_quarantine
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export results
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# Clearance
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# ---------------------------------------------
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#
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# This module is in charge of making the
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# "quarantined" network blocks
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# pass the firewall and be stored in the chain DAG
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logScope:
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topics = "clearance"
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template asSigVerified(x: SignedBeaconBlock): SigVerifiedSignedBeaconBlock =
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## This converts a signed beacon block to a sig verified beacon clock.
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## This assumes that their bytes representation is the same.
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##
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## At the GC-level, the GC is type-agnostic it's all type erased so
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## casting between seq[Attestation] and seq[TrustedAttestation]
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## will not disrupt GC operations.
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##
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## This SHOULD be used in function calls to avoid expensive temporary.
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## see https://github.com/status-im/nimbus-eth2/pull/2250#discussion_r562010679
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cast[ptr SigVerifiedSignedBeaconBlock](signedBlock.unsafeAddr)[]
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template asTrusted(x: SignedBeaconBlock or SigVerifiedBeaconBlock): TrustedSignedBeaconBlock =
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## This converts a sigverified beacon block to a trusted beacon clock.
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## This assumes that their bytes representation is the same.
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##
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## At the GC-level, the GC is type-agnostic it's all type erased so
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## casting between seq[Attestation] and seq[TrustedAttestation]
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## will not disrupt GC operations.
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##
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## This SHOULD be used in function calls to avoid expensive temporary.
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## see https://github.com/status-im/nimbus-eth2/pull/2250#discussion_r562010679
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cast[ptr TrustedSignedBeaconBlock](signedBlock.unsafeAddr)[]
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func getOrResolve*(dag: ChainDAGRef, quarantine: var QuarantineRef, root: Eth2Digest): BlockRef =
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## Fetch a block ref, or nil if not found (will be added to list of
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## blocks-to-resolve)
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result = dag.getRef(root)
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if result.isNil:
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quarantine.addMissing(root)
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proc batchVerify(quarantine: var QuarantineRef, sigs: openArray[SignatureSet]): bool =
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var secureRandomBytes: array[32, byte]
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quarantine.rng[].brHmacDrbgGenerate(secureRandomBytes)
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# TODO: For now only enable serial batch verification
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return batchVerifySerial(quarantine.sigVerifCache, sigs, secureRandomBytes)
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proc addRawBlock*(
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dag: var ChainDAGRef, quarantine: var QuarantineRef,
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signedBlock: SignedBeaconBlock, onBlockAdded: OnBlockAdded
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): Result[BlockRef, (ValidationResult, BlockError)] {.gcsafe.}
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proc addResolvedBlock(
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dag: var ChainDAGRef, quarantine: var QuarantineRef,
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state: var StateData, trustedBlock: TrustedSignedBeaconBlock,
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parent: BlockRef, cache: var StateCache,
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onBlockAdded: OnBlockAdded
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) =
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# TODO move quarantine processing out of here
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doAssert state.data.data.slot == trustedBlock.message.slot,
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"state must match block"
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doAssert state.blck.root == trustedBlock.message.parent_root,
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"the StateData passed into the addResolved function not yet updated!"
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let
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blockRoot = trustedBlock.root
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blockRef = BlockRef.init(blockRoot, trustedBlock.message)
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blockEpoch = blockRef.slot.compute_epoch_at_slot()
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link(parent, blockRef)
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var epochRef = dag.findEpochRef(parent, blockEpoch)
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if epochRef == nil:
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let prevEpochRef =
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if blockEpoch < 1: nil else: dag.findEpochRef(parent, blockEpoch - 1)
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epochRef = EpochRef.init(state.data.data, cache, prevEpochRef)
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dag.addEpochRef(blockRef, epochRef)
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dag.blocks.incl(KeyedBlockRef.init(blockRef))
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trace "Populating block dag", key = blockRoot, val = blockRef
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# Resolved blocks should be stored in database
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dag.putBlock(trustedBlock)
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var foundHead: BlockRef
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for head in dag.heads.mitems():
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if head.isAncestorOf(blockRef):
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head = blockRef
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foundHead = head
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break
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if foundHead.isNil:
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foundHead = blockRef
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dag.heads.add(foundHead)
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debug "Block resolved",
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blck = shortLog(trustedBlock.message),
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blockRoot = shortLog(blockRoot),
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heads = dag.heads.len()
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state.blck = blockRef
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# Notify others of the new block before processing the quarantine, such that
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# notifications for parents happens before those of the children
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if onBlockAdded != nil:
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onBlockAdded(blockRef, trustedBlock, epochRef, state.data)
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# Now that we have the new block, we should see if any of the previously
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# unresolved blocks magically become resolved
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# TODO This code is convoluted because when there are more than ~1.5k
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# blocks being synced, there's a stack overflow as `add` gets called
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# for the whole chain of blocks. Instead we use this ugly field in `dag`
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# which could be avoided by refactoring the code
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# TODO unit test the logic, in particular interaction with fork choice block parents
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if not quarantine.inAdd:
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quarantine.inAdd = true
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defer: quarantine.inAdd = false
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var entries = 0
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while entries != quarantine.orphans.len:
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entries = quarantine.orphans.len # keep going while quarantine is shrinking
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var resolved: seq[SignedBeaconBlock]
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for _, v in quarantine.orphans:
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if v.message.parent_root in dag:
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resolved.add(v)
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for v in resolved:
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discard addRawBlock(dag, quarantine, v, onBlockAdded)
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proc addRawBlockCheckStateTransition(
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dag: var ChainDAGRef, quarantine: var QuarantineRef,
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signedBlock: SomeSignedBeaconBlock, cache: var StateCache
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): (ValidationResult, BlockError) =
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## addRawBlock - Ensure block can be applied on a state
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let
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poolPtr = unsafeAddr dag # safe because restore is short-lived
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func restore(v: var HashedBeaconState) =
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# TODO address this ugly workaround - there should probably be a
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# `state_transition` that takes a `StateData` instead and updates
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# the block as well
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doAssert v.addr == addr poolPtr.clearanceState.data
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assign(poolPtr.clearanceState, poolPtr.headState)
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if not state_transition(dag.runtimePreset, dag.clearanceState.data, signedBlock,
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cache, dag.updateFlags + {slotProcessed}, restore):
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info "Invalid block"
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return (ValidationResult.Reject, Invalid)
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return (ValidationResult.Accept, default(BlockError))
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proc addRawBlockKnownParent(
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dag: var ChainDAGRef, quarantine: var QuarantineRef,
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signedBlock: SignedBeaconBlock,
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parent: BlockRef,
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onBlockAdded: OnBlockAdded
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): Result[BlockRef, (ValidationResult, BlockError)] =
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## addRawBlock - Block has a parent
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if parent.slot >= signedBlock.message.slot:
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# A block whose parent is newer than the block itself is clearly invalid -
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# discard it immediately
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debug "Invalid block slot",
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parentBlock = shortLog(parent)
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return err((ValidationResult.Reject, Invalid))
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if (parent.slot < dag.finalizedHead.slot) or
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(parent.slot == dag.finalizedHead.slot and
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parent != dag.finalizedHead.blck):
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# We finalized a block that's newer than the parent of this block - this
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# block, although recent, is thus building on a history we're no longer
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# interested in pursuing. This can happen if a client produces a block
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# while syncing - ie it's own head block will be old, but it'll create
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# a block according to the wall clock, in its own little world - this is
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# correct - from their point of view, the head block they have is the
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# latest thing that happened on the chain and they're performing their
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# duty correctly.
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debug "Unviable block, dropping",
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finalizedHead = shortLog(dag.finalizedHead),
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tail = shortLog(dag.tail)
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return err((ValidationResult.Ignore, Unviable))
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# The block might have been in either of `orphans` or `missing` - we don't
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# want any more work done on its behalf
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quarantine.removeOrphan(signedBlock)
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# The block is resolved, now it's time to validate it to ensure that the
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# blocks we add to the database are clean for the given state
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# TODO if the block is from the future, we should not be resolving it (yet),
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# but maybe we should use it as a hint that our clock is wrong?
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var cache = StateCache()
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updateStateData(
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dag, dag.clearanceState, parent.atSlot(signedBlock.message.slot), true, cache)
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# First batch verify crypto
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if skipBLSValidation notin dag.updateFlags:
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# TODO: remove skipBLSValidation
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var sigs: seq[SignatureSet]
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if not sigs.collectSignatureSets(signedBlock, dag.clearanceState.data.data, cache):
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# A PublicKey or Signature isn't on the BLS12-381 curve
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return err((ValidationResult.Reject, Invalid))
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if not quarantine.batchVerify(sigs):
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return err((ValidationResult.Reject, Invalid))
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static: doAssert sizeof(SignedBeaconBlock) == sizeof(SigVerifiedSignedBeaconBlock)
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let (valRes, blockErr) = addRawBlockCheckStateTransition(
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dag, quarantine, signedBlock.asSigVerified(), cache)
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if valRes != ValidationResult.Accept:
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return err((valRes, blockErr))
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# Careful, clearanceState.data has been updated but not blck - we need to
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# create the BlockRef first!
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addResolvedBlock(
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dag, quarantine, dag.clearanceState,
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signedBlock.asTrusted(),
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parent, cache,
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onBlockAdded)
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return ok dag.clearanceState.blck
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proc addRawBlockUnresolved(
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dag: var ChainDAGRef,
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quarantine: var QuarantineRef,
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signedBlock: SignedBeaconBlock
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): Result[BlockRef, (ValidationResult, BlockError)] =
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## addRawBlock - Block is unresolved / has no parent
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# This is an unresolved block - add it to the quarantine, which will cause its
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# parent to be scheduled for downloading
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if not quarantine.add(dag, signedBlock):
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debug "Block quarantine full"
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if signedBlock.message.parent_root in quarantine.missing or
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containsOrphan(quarantine, signedBlock):
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debug "Unresolved block (parent missing or orphaned)",
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orphans = quarantine.orphans.len,
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missing = quarantine.missing.len
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return err((ValidationResult.Ignore, MissingParent))
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# TODO if we receive spam blocks, one heurestic to implement might be to wait
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# for a couple of attestations to appear before fetching parents - this
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# would help prevent using up network resources for spam - this serves
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# two purposes: one is that attestations are likely to appear for the
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# block only if it's valid / not spam - the other is that malicious
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# validators that are not proposers can sign invalid blocks and send
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# them out without penalty - but signing invalid attestations carries
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# a risk of being slashed, making attestations a more valuable spam
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# filter.
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debug "Unresolved block (parent missing)",
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orphans = quarantine.orphans.len,
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missing = quarantine.missing.len
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return err((ValidationResult.Ignore, MissingParent))
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proc addRawBlock*(
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dag: var ChainDAGRef, quarantine: var QuarantineRef,
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signedBlock: SignedBeaconBlock,
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onBlockAdded: OnBlockAdded
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): Result[BlockRef, (ValidationResult, BlockError)] =
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## Try adding a block to the chain, verifying first that it passes the state
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## transition function and contains correct cryptographic signature.
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##
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## Cryptographic checks can be skipped by adding skipBLSValidation to dag.updateFlags
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logScope:
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blck = shortLog(signedBlock.message)
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blockRoot = shortLog(signedBlock.root)
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template blck(): untyped = signedBlock.message # shortcuts without copy
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template blockRoot(): untyped = signedBlock.root
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if blockRoot in dag:
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debug "Block already exists"
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# We should not call the block added callback for blocks that already
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# existed in the pool, as that may confuse consumers such as the fork
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# choice. While the validation result won't be accessed, it's IGNORE,
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# according to the spec.
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return err((ValidationResult.Ignore, Duplicate))
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quarantine.missing.del(blockRoot)
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# If the block we get is older than what we finalized already, we drop it.
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# One way this can happen is that we start resolving a block and finalization
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# happens in the meantime - the block we requested will then be stale
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# by the time it gets here.
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if blck.slot <= dag.finalizedHead.slot:
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debug "Old block, dropping",
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finalizedHead = shortLog(dag.finalizedHead),
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tail = shortLog(dag.tail)
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# Doesn't correspond to any specific validation condition, and still won't
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# be used, but certainly would be IGNORE.
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return err((ValidationResult.Ignore, Unviable))
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let parent = dag.getRef(blck.parent_root)
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if parent != nil:
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return addRawBlockKnownParent(dag, quarantine, signedBlock, parent, onBlockAdded)
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return addRawBlockUnresolved(dag, quarantine, signedBlock)
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