Jacek Sieka df7bc87af5 Pre-compute slot transition for clearance state
This way we perform the expensive epoch processing before the block
arrives.

Of course, this may lead to speculative misses which in turn lead to
replays - it's likely that in the case of a miss, we'll see a replay
regardless.
2021-05-30 12:04:09 +03:00

365 lines
14 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
from libp2p/protocols/pubsub/pubsub import ValidationResult
export results, ValidationResult
# 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
static: # TODO See isomorphicCast
doAssert sizeof(SignedBeaconBlock) == sizeof(SigVerifiedSignedBeaconBlock)
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
static: # TODO See isomorphicCast
doAssert sizeof(x) == sizeof(TrustedSignedBeaconBlock)
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, stateDataDur, sigVerifyDur,
stateVerifyDur: Duration
) =
# TODO move quarantine processing out of here
doAssert getStateField(state, 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)
startTick = Moment.now()
link(parent, blockRef)
dag.blocks.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)
# Up to here, state.data was referring to the new state after the block had
# been applied but the `blck` field was still set to the parent
state.blck = blockRef
# Getting epochRef with the state will potentially create a new EpochRef
let
epochRef = dag.getEpochRef(state, cache)
epochRefTick = Moment.now()
debug "Block resolved",
blck = shortLog(trustedBlock.message),
blockRoot = shortLog(blockRoot),
heads = dag.heads.len(),
stateDataDur, sigVerifyDur, stateVerifyDur,
putBlockDur = putBlockTick - startTick,
epochRefDur = epochRefTick - putBlockTick
# 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: ChainDAGRef, quarantine: var QuarantineRef,
signedBlock: SomeSignedBeaconBlock, cache: var StateCache
): (ValidationResult, BlockError) =
## addRawBlock - Ensure block can be applied on a state
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 dag.clearanceState.data
assign(dag.clearanceState, dag.headState)
logScope:
blck = shortLog(signedBlock.message)
blockRoot = shortLog(signedBlock.root)
var rewards: RewardInfo
if not state_transition(dag.runtimePreset, dag.clearanceState.data, signedBlock,
cache, rewards, dag.updateFlags + {slotProcessed}, restore):
info "Invalid block"
return (ValidationResult.Reject, Invalid)
return (ValidationResult.Accept, default(BlockError))
proc advanceClearanceState*(dag: var 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!
if dag.clearanceState.blck.slot == getStateField(dag.clearanceState, slot):
let next = dag.clearanceState.blck.atSlot(
getStateField(dag.clearanceState, slot) + 1)
debug "Preparing clearance state for next block", next
var cache = StateCache()
updateStateData(dag, dag.clearanceState,next, true, cache)
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
let startTick = Moment.now()
# 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)
let stateDataTick = Moment.now()
# First batch verify crypto
if skipBLSValidation notin dag.updateFlags:
# TODO: remove skipBLSValidation
var sigs: seq[SignatureSet]
if not sigs.collectSignatureSets(signedBlock, dag.clearanceState, 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))
let sigVerifyTick = Moment.now()
let (valRes, blockErr) = addRawBlockCheckStateTransition(
dag, quarantine, signedBlock.asSigVerified(), cache)
if valRes != ValidationResult.Accept:
return err((valRes, blockErr))
let stateVerifyTick = Moment.now()
# 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,
stateDataDur = stateDataTick - startTick,
sigVerifyDur = sigVerifyTick - stateDataTick,
stateVerifyDur = stateVerifyTick - sigVerifyTick)
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
logScope:
blck = shortLog(signedBlock.message)
blockRoot = shortLog(signedBlock.root)
# 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)