nimbus-eth2/beacon_chain/consensus_object_pools/block_clearance.nim

330 lines
13 KiB
Nim

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