nimbus-eth2/beacon_chain/consensus_object_pools/blockchain_dag_light_client...

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45 KiB
Nim

# beacon_chain
# Copyright (c) 2022-2024 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: [].}
import
# Status libraries
stew/bitops2,
# Beacon chain internals
../spec/forks,
../beacon_chain_db_light_client,
"."/[block_pools_types, blockchain_dag]
logScope: topics = "chaindag_lc"
template nextEpochBoundarySlot(slot: Slot): Slot =
## Compute the first possible epoch boundary state slot of a `Checkpoint`
## referring to a block at given slot.
(slot + (SLOTS_PER_EPOCH - 1)).epoch.start_slot
proc updateExistingState(
dag: ChainDAGRef, state: var ForkedHashedBeaconState, bsi: BlockSlotId,
save: bool, cache: var StateCache): bool =
## Wrapper around `updateState` for states expected to exist.
let ok = dag.updateState(state, bsi, save, cache)
if not ok:
error "State failed to load unexpectedly", bsi, tail = dag.tail.slot
doAssert strictVerification notin dag.updateFlags
ok
template withUpdatedExistingState(
dag: ChainDAGRef, stateParam: var ForkedHashedBeaconState,
bsiParam: BlockSlotId, okBody: untyped, failureBody: untyped): untyped =
## Wrapper around `withUpdatedState` for states expected to exist.
block:
let bsi = bsiParam
dag.withUpdatedState(stateParam, bsiParam) do:
okBody
do:
error "State failed to load unexpectedly", bsi, tail = dag.tail.slot
doAssert strictVerification notin dag.updateFlags
failureBody
proc getExistingBlockIdAtSlot(dag: ChainDAGRef, slot: Slot): Opt[BlockSlotId] =
## Wrapper around `getBlockIdAtSlot` for blocks expected to exist.
let bsi = dag.getBlockIdAtSlot(slot)
if bsi.isNone:
error "Block failed to load unexpectedly", slot, tail = dag.tail.slot
doAssert strictVerification notin dag.updateFlags
bsi
proc existingParent(dag: ChainDAGRef, bid: BlockId): Opt[BlockId] =
## Wrapper around `parent` for parents known to exist.
let parent = dag.parent(bid)
if parent.isNone:
error "Parent failed to load unexpectedly", bid, tail = dag.tail.slot
doAssert strictVerification notin dag.updateFlags
parent
proc getExistingForkedBlock(
dag: ChainDAGRef, bid: BlockId): Opt[ForkedTrustedSignedBeaconBlock] =
## Wrapper around `getForkedBlock` for blocks expected to exist.
let bdata = dag.getForkedBlock(bid)
if bdata.isNone:
error "Block failed to load unexpectedly", bid, tail = dag.tail.slot
doAssert strictVerification notin dag.updateFlags
bdata
proc existingCurrentSyncCommitteeForPeriod(
dag: ChainDAGRef,
tmpState: var ForkedHashedBeaconState,
period: SyncCommitteePeriod): Opt[SyncCommittee] =
## Wrapper around `currentSyncCommitteeForPeriod` for states known to exist.
let syncCommittee = dag.currentSyncCommitteeForPeriod(tmpState, period)
if syncCommittee.isNone:
error "Current sync committee failed to load unexpectedly",
period, tail = dag.tail.slot
doAssert strictVerification notin dag.updateFlags
syncCommittee
func pruneToCapacity[A, B](t: var OrderedTable[A, B], capacity: int) =
while t.len > capacity:
var key {.noinit.}: A
for k in t.keys:
key = k
break
t.del(key)
func cacheRecentLightClientHeader(
dag: ChainDAGRef, bid: BlockId, header: ForkedLightClientHeader) =
dag.lcDataStore.cache.recentHeaders[bid] = header
dag.lcDataStore.cache.recentHeaders.pruneToCapacity(10)
func cacheRecentSyncAggregate(
dag: ChainDAGRef, bid: BlockId, syncAggregate: SyncAggregate) =
dag.lcDataStore.cache.recentSyncAggregates[bid] = syncAggregate
dag.lcDataStore.cache.recentSyncAggregates.pruneToCapacity(5)
func lightClientHeader(
blck: ForkyTrustedSignedBeaconBlock): ForkedLightClientHeader =
const lcDataFork = max(
lcDataForkAtConsensusFork(typeof(blck).kind), LightClientDataFork.Altair)
ForkedLightClientHeader.init(blck.toLightClientHeader(lcDataFork))
func syncAggregate(
blck: ForkyTrustedSignedBeaconBlock): SyncAggregate =
blck.asSigned().message.body.sync_aggregate
proc getExistingLightClientHeader(
dag: ChainDAGRef, bid: BlockId): ForkedLightClientHeader =
var res = dag.lcDataStore.cache.recentHeaders.getOrDefault(bid)
if res.kind > LightClientDataFork.None:
return res
let bdata = dag.getExistingForkedBlock(bid)
if bdata.isNone:
return res
res = withBlck(bdata.get): forkyBlck.lightClientHeader()
dag.cacheRecentLightClientHeader(bid, res)
res
proc getExistingSyncAggregate(
dag: ChainDAGRef, bid: BlockId): Opt[SyncAggregate] =
if bid in dag.lcDataStore.cache.recentSyncAggregates:
return Opt.some dag.lcDataStore.cache.recentSyncAggregates.getOrDefault(bid)
let bdata = dag.getExistingForkedBlock(bid)
if bdata.isNone:
return Opt.none(SyncAggregate)
let res = withBlck(bdata.get):
when consensusFork >= ConsensusFork.Altair:
Opt.some forkyBlck.syncAggregate()
else:
return Opt.none(SyncAggregate)
dag.cacheRecentSyncAggregate(bid, res.get)
res
proc initLightClientDataStore*(
config: LightClientDataConfig,
cfg: RuntimeConfig,
db: LightClientDataDB): LightClientDataStore =
## Initialize light client data store.
let
defaultMaxPeriods = cfg.defaultLightClientDataMaxPeriods
maxPeriods = config.maxPeriods.get(distinctBase(SyncCommitteePeriod.high))
if maxPeriods < defaultMaxPeriods:
warn "Retaining fewer periods than recommended",
lightClientDataMaxPeriods = config.maxPeriods,
specRecommendation = defaultMaxPeriods
LightClientDataStore(
db: db,
serve: config.serve,
importMode: config.importMode,
maxPeriods: maxPeriods,
onLightClientFinalityUpdate: config.onLightClientFinalityUpdate,
onLightClientOptimisticUpdate: config.onLightClientOptimisticUpdate)
func targetLightClientTailSlot(dag: ChainDAGRef): Slot =
## Earliest slot for which light client data is retained.
let
maxPeriods = dag.lcDataStore.maxPeriods
headPeriod = dag.head.slot.sync_committee_period
lowSlot = dag.cfg.ALTAIR_FORK_EPOCH.start_slot
tail = max(headPeriod + 1, maxPeriods.SyncCommitteePeriod) - maxPeriods
max(tail.start_slot, lowSlot)
func handleUnexpectedLightClientError(dag: ChainDAGRef, buggedSlot: Slot) =
## If there is an unexpected error, adjust `tailSlot` to keep track of the
## section for which complete light client data is available, and to avoid
## failed lookups of cached light client data.
doAssert strictVerification notin dag.updateFlags
if buggedSlot >= dag.lcDataStore.cache.tailSlot:
dag.lcDataStore.cache.tailSlot = buggedSlot + 1
proc initLightClientBootstrapForPeriod(
dag: ChainDAGRef,
period: SyncCommitteePeriod): Opt[void] =
## Compute and cache `LightClientBootstrap` data for all finalized
## epoch boundary blocks within a given sync committee period.
if dag.finalizedHead.slot < period.start_slot:
return ok()
if dag.finalizedHead.slot < dag.cfg.ALTAIR_FORK_EPOCH.start_slot:
return ok()
if dag.lcDataStore.db.isPeriodSealed(period):
return ok()
let startTick = Moment.now()
debug "Caching historic LC bootstrap data", period
defer:
let endTick = Moment.now()
debug "Historic LC bootstrap data cached", period,
cacheDur = endTick - startTick
let
periodStartSlot = period.start_slot
periodEndSlot = periodStartSlot + SLOTS_PER_SYNC_COMMITTEE_PERIOD - 1
tailSlot = max(dag.targetLightClientTailSlot, dag.tail.slot)
lowSlot = max(periodStartSlot, tailSlot)
highSlot = min(periodEndSlot, dag.finalizedHead.blck.slot)
lowBoundarySlot = lowSlot.nextEpochBoundarySlot
highBoundarySlot = highSlot.nextEpochBoundarySlot
var
res = ok()
tmpState = assignClone(dag.headState)
tmpCache: StateCache
nextBoundarySlot = lowBoundarySlot
while nextBoundarySlot <= highBoundarySlot:
defer: nextBoundarySlot += SLOTS_PER_EPOCH
let
bsi = dag.getExistingBlockIdAtSlot(nextBoundarySlot).valueOr:
dag.handleUnexpectedLightClientError(nextBoundarySlot)
res.err()
continue
bid = bsi.bid
boundarySlot = bid.slot.nextEpochBoundarySlot
if boundarySlot == nextBoundarySlot and bid.slot >= lowSlot and
not dag.lcDataStore.db.hasCurrentSyncCommitteeBranch(bid.slot):
let bdata = dag.getExistingForkedBlock(bid).valueOr:
dag.handleUnexpectedLightClientError(bid.slot)
res.err()
continue
if not dag.updateExistingState(
tmpState[], bid.atSlot, save = false, tmpCache):
dag.handleUnexpectedLightClientError(bid.slot)
res.err()
continue
withStateAndBlck(tmpState[], bdata):
when consensusFork >= ConsensusFork.Altair:
const lcDataFork = lcDataForkAtConsensusFork(consensusFork)
if not dag.lcDataStore.db.hasSyncCommittee(period):
dag.lcDataStore.db.putSyncCommittee(
period, forkyState.data.current_sync_committee)
dag.lcDataStore.db.putHeader(
forkyBlck.toLightClientHeader(lcDataFork))
dag.lcDataStore.db.putCurrentSyncCommitteeBranch(
bid.slot, forkyState.data.build_proof(
altair.CURRENT_SYNC_COMMITTEE_GINDEX).get)
else: raiseAssert "Unreachable"
res
proc initLightClientUpdateForPeriod(
dag: ChainDAGRef, period: SyncCommitteePeriod): Opt[void] =
## Compute and cache the best `LightClientUpdate` within a given
## sync committee period up through the finalized head block.
## Non-finalized blocks are processed incrementally by other functions.
## Should not be called for periods for which incremental computation started.
if dag.finalizedHead.slot < period.start_slot:
return ok()
if dag.finalizedHead.slot < dag.cfg.ALTAIR_FORK_EPOCH.start_slot:
return ok()
if dag.lcDataStore.db.isPeriodSealed(period):
return ok()
let startTick = Moment.now()
debug "Computing best historic LC update", period
proc logBest(endTick = Moment.now()) =
# Using a helper function reduces code size as the `defer` beneath is
# replicated on every `return`, and the log statement allocates another
# copy of the arguments on the stack for each instantiation (~1 MB stack!)
debug "Best historic LC update computed",
period, update = dag.lcDataStore.db.getBestUpdate(period),
computeDur = endTick - startTick
defer: logBest()
proc maxParticipantsBlock(
dag: ChainDAGRef, highBid: BlockId, lowSlot: Slot
): tuple[bid: Opt[BlockId], res: Opt[void]] =
## Determine the earliest block with most sync committee signatures among
## ancestors of `highBid` with at least `lowSlot` as parent block slot.
## Return `err` if no block with `MIN_SYNC_COMMITTEE_PARTICIPANTS` exists.
## `res` in result indicates whether no unexpected errors occurred.
var
maxParticipants = MIN_SYNC_COMMITTEE_PARTICIPANTS
maxBid: Opt[BlockId]
res = Opt[void].ok()
bid = highBid
while true:
if bid.slot <= lowSlot:
break
let parentBid = dag.existingParent(bid).valueOr:
dag.handleUnexpectedLightClientError(bid.slot)
res.err()
break
if parentBid.slot < lowSlot:
break
let
bdata = dag.getExistingForkedBlock(bid).valueOr:
dag.handleUnexpectedLightClientError(bid.slot)
res.err()
break
numParticipants =
withBlck(bdata):
when consensusFork >= ConsensusFork.Altair:
forkyBlck.message.body.sync_aggregate.num_active_participants
else: raiseAssert "Unreachable"
if numParticipants >= maxParticipants:
maxParticipants = numParticipants
maxBid.ok bid
bid = parentBid
(bid: maxBid, res: res)
# Determine the block in the period with highest sync committee participation
let
periodStartSlot = period.start_slot
periodEndSlot = periodStartSlot + SLOTS_PER_SYNC_COMMITTEE_PERIOD - 1
tailSlot = max(dag.targetLightClientTailSlot, dag.tail.slot)
lowSlot = max(periodStartSlot, tailSlot)
highSlot = min(periodEndSlot, dag.finalizedHead.blck.slot)
highBsi = dag.getExistingBlockIdAtSlot(highSlot).valueOr:
dag.handleUnexpectedLightClientError(highSlot)
return err()
highBid = highBsi.bid
maxParticipantsRes = dag.maxParticipantsBlock(highBid, lowSlot)
maxParticipantsBid = maxParticipantsRes.bid.valueOr:
const update = default(ForkedLightClientUpdate)
dag.lcDataStore.db.putBestUpdate(period, update)
return maxParticipantsRes.res
# The block with highest participation may refer to a `finalized_checkpoint`
# in a different sync committee period. If that is the case, search for a
# later block with a `finalized_checkpoint` within the given sync committee
# period, despite it having a lower sync committee participation
var
res = ok()
tmpState = assignClone(dag.headState)
signatureBid {.noinit.}, finalizedBid {.noinit.}: BlockId
signatureBid.slot = FAR_FUTURE_SLOT
finalizedBid.slot = FAR_FUTURE_SLOT
while true:
if signatureBid.slot == FAR_FUTURE_SLOT:
signatureBid = maxParticipantsBid
else:
let signatureRes = dag.maxParticipantsBlock(highBid, signatureBid.slot)
if signatureRes.res.isErr:
res.err()
signatureBid = signatureRes.bid.valueOr:
signatureBid = maxParticipantsBid
break
let
attestedBid = dag.existingParent(signatureBid).valueOr:
dag.handleUnexpectedLightClientError(signatureBid.slot)
res.err()
continue
finalizedEpoch = block:
dag.withUpdatedExistingState(tmpState[], attestedBid.atSlot) do:
withState(updatedState):
when consensusFork >= ConsensusFork.Altair:
forkyState.data.finalized_checkpoint.epoch
else: raiseAssert "Unreachable"
do:
dag.handleUnexpectedLightClientError(attestedBid.slot)
res.err()
continue
finalizedSlot = finalizedEpoch.start_slot
finalizedBsi =
if finalizedSlot >= dag.tail.slot:
dag.getExistingBlockIdAtSlot(finalizedSlot).valueOr:
dag.handleUnexpectedLightClientError(finalizedSlot)
res.err()
continue
else:
continue
if finalizedBsi.bid.slot >= lowSlot:
finalizedBid = finalizedBsi.bid
break
if signatureBid == maxParticipantsBid:
finalizedBid = finalizedBsi.bid # For fallback `break` at start of loop
# Save best light client data for given period
var update {.noinit.}: ForkedLightClientUpdate
let attestedBid = dag.existingParent(signatureBid).valueOr:
dag.handleUnexpectedLightClientError(signatureBid.slot)
return err()
dag.withUpdatedExistingState(tmpState[], attestedBid.atSlot) do:
let bdata = dag.getExistingForkedBlock(bid).valueOr:
dag.handleUnexpectedLightClientError(bid.slot)
return err()
withStateAndBlck(updatedState, bdata):
when consensusFork >= ConsensusFork.Altair:
const lcDataFork = lcDataForkAtConsensusFork(consensusFork)
update = ForkedLightClientUpdate.init(lcDataFork.LightClientUpdate(
attested_header: forkyBlck.toLightClientHeader(lcDataFork),
next_sync_committee: forkyState.data.next_sync_committee,
next_sync_committee_branch:
forkyState.data.build_proof(altair.NEXT_SYNC_COMMITTEE_GINDEX).get,
finality_branch:
if finalizedBid.slot != FAR_FUTURE_SLOT:
forkyState.data.build_proof(altair.FINALIZED_ROOT_GINDEX).get
else:
default(FinalityBranch)))
else: raiseAssert "Unreachable"
do:
dag.handleUnexpectedLightClientError(attestedBid.slot)
return err()
if finalizedBid.slot != FAR_FUTURE_SLOT and finalizedBid.slot != GENESIS_SLOT:
let bdata = dag.getExistingForkedBlock(finalizedBid).valueOr:
dag.handleUnexpectedLightClientError(finalizedBid.slot)
return err()
withBlck(bdata):
withForkyUpdate(update):
when lcDataFork > LightClientDataFork.None:
when lcDataFork >= lcDataForkAtConsensusFork(consensusFork):
forkyUpdate.finalized_header =
forkyBlck.toLightClientHeader(lcDataFork)
else: raiseAssert "Unreachable"
let bdata = dag.getExistingForkedBlock(signatureBid).valueOr:
dag.handleUnexpectedLightClientError(signatureBid.slot)
return err()
withBlck(bdata):
when consensusFork >= ConsensusFork.Altair:
withForkyUpdate(update):
when lcDataFork > LightClientDataFork.None:
forkyUpdate.sync_aggregate =
forkyBlck.asSigned().message.body.sync_aggregate
else: raiseAssert "Unreachable"
withForkyUpdate(update):
when lcDataFork > LightClientDataFork.None:
forkyUpdate.signature_slot = signatureBid.slot
dag.lcDataStore.db.putBestUpdate(period, update)
res
proc initLightClientDataForPeriod(
dag: ChainDAGRef, period: SyncCommitteePeriod): Opt[void] =
## Import light client data for a given sync committee period.
if dag.lcDataStore.db.isPeriodSealed(period):
return ok()
let
fullPeriodCovered = (dag.finalizedHead.slot >= (period + 1).start_slot)
res1 = dag.initLightClientBootstrapForPeriod(period)
res2 = dag.initLightClientUpdateForPeriod(period)
if res1.isErr or res2.isErr:
return err()
if fullPeriodCovered:
dag.lcDataStore.db.sealPeriod(period)
ok()
proc getLightClientData(
dag: ChainDAGRef,
bid: BlockId): CachedLightClientData =
## Fetch cached light client data about a given block.
## Data must be cached (`cacheLightClientData`) before calling this function.
try: dag.lcDataStore.cache.data[bid]
except KeyError: raiseAssert "Unreachable"
proc cacheLightClientData(
dag: ChainDAGRef,
state: ForkyHashedBeaconState,
blck: ForkyTrustedSignedBeaconBlock,
current_period_best_update: ref ForkedLightClientUpdate,
latest_signature_slot: Slot) =
## Cache data for a given block and its post-state to speed up creating future
## `LightClientUpdate` and `LightClientBootstrap` instances that refer to this
## block and state.
let
bid = blck.toBlockId()
cachedData = CachedLightClientData(
current_sync_committee_branch:
state.data.build_proof(altair.CURRENT_SYNC_COMMITTEE_GINDEX).get,
next_sync_committee_branch:
state.data.build_proof(altair.NEXT_SYNC_COMMITTEE_GINDEX).get,
finalized_slot:
state.data.finalized_checkpoint.epoch.start_slot,
finality_branch:
state.data.build_proof(altair.FINALIZED_ROOT_GINDEX).get,
current_period_best_update:
current_period_best_update,
latest_signature_slot:
latest_signature_slot)
if dag.lcDataStore.cache.data.hasKeyOrPut(bid, cachedData):
doAssert false, "Redundant `cacheLightClientData` call"
dag.cacheRecentLightClientHeader(bid, blck.lightClientHeader())
dag.cacheRecentSyncAggregate(bid, blck.syncAggregate())
func shouldImportLcData(dag: ChainDAGRef): bool =
dag.lcDataStore.importMode != LightClientDataImportMode.None and
dag.cfg.ALTAIR_FORK_EPOCH != FAR_FUTURE_EPOCH
proc deleteLightClientData*(dag: ChainDAGRef, bid: BlockId) =
## Delete cached light client data for a given block. This needs to be called
## when a block becomes unreachable due to finalization of a different fork.
if not dag.shouldImportLcData:
return
dag.lcDataStore.cache.data.del bid
proc assignLightClientData(
obj: var SomeForkedLightClientUpdateWithFinality,
dag: ChainDAGRef,
attested_bid: BlockId,
signature_slot: Slot,
sync_aggregate: SyncAggregate,
next_sync_committee = Opt.none(SyncCommittee)): Opt[void] {.discardable.} =
## Update `obj` based on `attested_bid` / `signature_slot` / `sync_aggregate`
## and `next_sync_committee` (for full `LightClientUpdate`).
## Return `ok` if there were changes; `err` otherwise.
# If `sync_aggregate` is unchanged, the rest is also unchanged
withForkyObject(obj):
when lcDataFork > LightClientDataFork.None:
if forkyObject.signature_slot == signature_slot and
forkyObject.sync_aggregate == sync_aggregate:
return err()
# Bump `attested_header`; if it is unchanged, finality info is also unchanged
let new_attested_header = withForkyObject(obj):
when lcDataFork > LightClientDataFork.None:
template beacon_header: untyped = forkyObject.attested_header.beacon
beacon_header.slot != attested_bid.slot or
beacon_header.hash_tree_root() != attested_bid.root
else:
true
if new_attested_header:
let att_header = dag.getExistingLightClientHeader(attested_bid)
withForkyHeader(att_header):
when lcDataFork > LightClientDataFork.None:
obj.migrateToDataFork(lcDataFork)
obj.forky(lcDataFork).attested_header = forkyHeader
else:
dag.handleUnexpectedLightClientError(attested_bid.slot)
return err()
var attested_data = dag.getLightClientData(attested_bid)
when obj is SomeForkedLightClientUpdateWithSyncCommittee:
doAssert next_sync_committee.isSome
withForkyObject(obj):
when lcDataFork > LightClientDataFork.None:
forkyObject.next_sync_committee =
next_sync_committee.get
forkyObject.next_sync_committee_branch =
attested_data.next_sync_committee_branch
else:
doAssert next_sync_committee.isNone
var finalized_slot = attested_data.finalized_slot
withForkyObject(obj):
when lcDataFork > LightClientDataFork.None:
if finalized_slot == forkyObject.finalized_header.beacon.slot:
forkyObject.finality_branch = attested_data.finality_branch
elif finalized_slot < dag.tail.slot:
forkyObject.finalized_header.reset()
forkyObject.finality_branch.reset()
else:
let finalized_bsi = dag.getExistingBlockIdAtSlot(finalized_slot)
if finalized_bsi.isNone:
dag.handleUnexpectedLightClientError(finalized_slot)
forkyObject.finalized_header.reset()
forkyObject.finality_branch.reset()
else:
let finalized_bid = finalized_bsi.get.bid
if finalized_bid.slot != finalized_slot:
# Empty slots at end of epoch, update cache for latest block slot
finalized_slot = finalized_bid.slot
attested_data.finalized_slot = finalized_slot
dag.lcDataStore.cache.data[attested_bid] = attested_data
if finalized_slot == forkyObject.finalized_header.beacon.slot:
forkyObject.finality_branch = attested_data.finality_branch
elif finalized_slot == GENESIS_SLOT:
forkyObject.finalized_header.reset()
forkyObject.finality_branch = attested_data.finality_branch
else:
var fin_header = dag.getExistingLightClientHeader(finalized_bid)
if fin_header.kind == LightClientDataFork.None:
dag.handleUnexpectedLightClientError(finalized_bid.slot)
forkyObject.finalized_header.reset()
forkyObject.finality_branch.reset()
else:
fin_header.migrateToDataFork(lcDataFork)
forkyObject.finalized_header = fin_header.forky(lcDataFork)
forkyObject.finality_branch = attested_data.finality_branch
withForkyObject(obj):
when lcDataFork > LightClientDataFork.None:
forkyObject.sync_aggregate = sync_aggregate
forkyObject.signature_slot = signature_slot
ok()
proc createLightClientUpdate(
dag: ChainDAGRef,
state: ForkyHashedBeaconState,
blck: ForkyTrustedSignedBeaconBlock,
parent_bid: BlockId) =
## Create `LightClientUpdate` instances for a given block and its post-state,
## and keep track of best / latest ones. Data about the parent block's
## post-state must be cached (`cacheLightClientData`) before calling this.
# Verify attested block (parent) is recent enough and that state is available
template attested_bid(): auto = parent_bid
let attested_slot = attested_bid.slot
if attested_slot < dag.lcDataStore.cache.tailSlot:
dag.cacheLightClientData(state, blck,
current_period_best_update = (ref ForkedLightClientUpdate)(),
latest_signature_slot = GENESIS_SLOT)
return
# If sync committee period changed, reset `best`
let
attested_period = attested_slot.sync_committee_period
signature_slot = blck.message.slot
signature_period = signature_slot.sync_committee_period
attested_data = dag.getLightClientData(attested_bid)
var best =
if attested_period != signature_period:
(ref ForkedLightClientUpdate)()
else:
attested_data.current_period_best_update
# If sync committee does not have sufficient participants, do not bump latest
template sync_aggregate(): auto = blck.asSigned().message.body.sync_aggregate
let
num_active_participants = sync_aggregate.num_active_participants.uint64
latest_signature_slot =
if num_active_participants < MIN_SYNC_COMMITTEE_PARTICIPANTS:
attested_data.latest_signature_slot
else:
signature_slot
# To update `best`, sync committee must have sufficient participants, and
# `signature_slot` must be in `attested_slot`'s sync committee period
if num_active_participants < MIN_SYNC_COMMITTEE_PARTICIPANTS or
attested_period != signature_period:
dag.cacheLightClientData(state, blck,
current_period_best_update = best,
latest_signature_slot = latest_signature_slot)
return
# Check if light client data improved
let
finalized_slot = attested_data.finalized_slot
finalized_bsi =
if finalized_slot >= dag.tail.slot:
dag.getExistingBlockIdAtSlot(finalized_slot)
else:
Opt.none(BlockSlotId)
has_finality =
finalized_bsi.isSome and
finalized_bsi.get.bid.slot >= dag.tail.slot
meta = LightClientUpdateMetadata(
attested_slot: attested_slot,
finalized_slot: finalized_slot,
signature_slot: signature_slot,
has_sync_committee: true,
has_finality: has_finality,
num_active_participants: num_active_participants)
is_better = is_better_data(
meta, attested_data.current_period_best_update[].toMeta())
if not is_better:
dag.cacheLightClientData(state, blck,
current_period_best_update = best,
latest_signature_slot = latest_signature_slot)
return
# Update best light client data for current sync committee period
best = newClone attested_data.current_period_best_update[]
let res = best[].assignLightClientData(
dag, attested_bid, signature_slot, sync_aggregate,
Opt.some(state.data.next_sync_committee))
if not res.isOk:
dag.cacheLightClientData(state, blck,
current_period_best_update = attested_data.current_period_best_update,
latest_signature_slot = latest_signature_slot)
return
debug "Best LC update improved", period = attested_period, update = best[]
dag.cacheLightClientData(state, blck,
current_period_best_update = best,
latest_signature_slot = latest_signature_slot)
proc createLightClientBootstrap(
dag: ChainDAGRef, bid: BlockId): Opt[void] =
let
bdata = ? dag.getExistingForkedBlock(bid)
period = bid.slot.sync_committee_period
if not dag.lcDataStore.db.hasSyncCommittee(period):
let didPutSyncCommittee = withState(dag.headState):
when consensusFork >= ConsensusFork.Altair:
if period == forkyState.data.slot.sync_committee_period:
dag.lcDataStore.db.putSyncCommittee(
period, forkyState.data.current_sync_committee)
true
else:
false
else:
false
if not didPutSyncCommittee:
let
tmpState = assignClone(dag.headState)
syncCommittee = ? dag.existingCurrentSyncCommitteeForPeriod(
tmpState[], period)
dag.lcDataStore.db.putSyncCommittee(period, syncCommittee)
withBlck(bdata):
when consensusFork >= ConsensusFork.Altair:
const lcDataFork = lcDataForkAtConsensusFork(consensusFork)
dag.lcDataStore.db.putHeader(
forkyBlck.toLightClientHeader(lcDataFork))
else: raiseAssert "Unreachable"
dag.lcDataStore.db.putCurrentSyncCommitteeBranch(
bid.slot, dag.getLightClientData(bid).current_sync_committee_branch)
ok()
proc initLightClientDataCache*(dag: ChainDAGRef) =
## Initialize cached light client data
if not dag.shouldImportLcData:
return
# Initialize tail slot.
# Both state and blocks must be available to construct light client data,
# see `cacheLightClientData`. If blocks are unavailable, most parts of the
# `LightClientHeader` could be reconstructed from the corresponding post-state
# but `execution_branch` (since Capella) requires full block availability.
# If the assumed-to-be-available range of states / blocks turns out to be
# actually unavailable (database inconsistencies), the `tailSlot` will adjust
# using `handleUnexpectedLightClientError`. This is unexpected and is logged,
# but recoverable by excluding the unavailable range from LC data collection.
let targetTailSlot = max(
# User configured horizon
dag.targetLightClientTailSlot,
max(
# State availability, needed for `cacheLightClientData`
dag.tail.slot,
# Block availability, needed for `LightClientHeader.execution_branch`
if dag.backfill.slot != GENESIS_SLOT:
let existing = dag.getBlockIdAtSlot(dag.backfill.slot)
if existing.isSome:
if dag.getForkedBlock(existing.get.bid).isNone:
# Special case: when starting with only a checkpoint state,
# we will not have the head block data in the database
dag.backfill.slot + 1
else:
dag.backfill.slot
else:
dag.backfill.slot
else:
dag.backfill.slot))
dag.lcDataStore.cache.tailSlot = max(dag.head.slot, targetTailSlot)
if dag.head.slot < dag.lcDataStore.cache.tailSlot:
return
# Import light client data for finalized period through finalized head
let
finalizedSlot = max(dag.finalizedHead.blck.slot, targetTailSlot)
finalizedPeriod = finalizedSlot.sync_committee_period
var res =
if dag.lcDataStore.importMode == LightClientDataImportMode.OnlyNew:
Opt[void].ok()
elif finalizedSlot >= dag.lcDataStore.cache.tailSlot:
Opt[void].ok()
else:
dag.lcDataStore.cache.tailSlot = finalizedSlot
dag.initLightClientDataForPeriod(finalizedPeriod)
let lightClientStartTick = Moment.now()
logScope:
lightClientDataMaxPeriods = dag.lcDataStore.maxPeriods
importMode = dag.lcDataStore.importMode
debug "Initializing cached LC data", res, targetTailSlot
proc isSyncAggregateCanonical(
dag: ChainDAGRef, state: ForkyHashedBeaconState,
sync_aggregate: TrustedSyncAggregate, signature_slot: Slot): bool =
if signature_slot > state.data.slot:
return false
let bid = dag.getBlockIdAtSlot(state, signature_slot).valueOr:
return false
if bid.slot != signature_slot:
return false
let bdata = dag.getForkedBlock(bid).valueOr:
return false
withBlck(bdata):
when consensusFork >= ConsensusFork.Altair:
forkyBlck.message.body.sync_aggregate == sync_aggregate
else:
false
# Build list of blocks to process.
# As it is slow to load states in descending order,
# build a reverse todo list to then process them in ascending order
let tailSlot = dag.lcDataStore.cache.tailSlot
var
blocks = newSeqOfCap[BlockId](dag.head.slot - tailSlot + 1)
bid = dag.head.bid
while bid.slot > tailSlot:
blocks.add bid
bid = dag.existingParent(bid).valueOr:
dag.handleUnexpectedLightClientError(bid.slot)
res.err()
break
if bid.slot == tailSlot:
blocks.add bid
# Process blocks (reuses `dag.headState`, but restores it to the current head)
var cache: StateCache
for i in countdown(blocks.high, blocks.low):
bid = blocks[i]
if not dag.updateExistingState(
dag.headState, bid.atSlot(), save = false, cache):
dag.handleUnexpectedLightClientError(bid.slot)
res.err()
continue
let bdata = dag.getExistingForkedBlock(bid).valueOr:
dag.handleUnexpectedLightClientError(bid.slot)
res.err()
continue
withStateAndBlck(dag.headState, bdata):
when consensusFork >= ConsensusFork.Altair:
if i == blocks.high:
let
period = bid.slot.sync_committee_period
best = newClone dag.lcDataStore.db.getBestUpdate(period)
withForkyUpdate(best[]):
when lcDataFork > LightClientDataFork.None:
let
attestedSlot = forkyUpdate.attested_header.beacon.slot
signatureSlot = forkyUpdate.signature_slot
if attestedSlot.sync_committee_period != period or
signatureSlot.sync_committee_period != period:
error "Invalid LC data cached", best = best[], period
best[].reset()
elif not dag.isSyncAggregateCanonical(
forkyState,
forkyUpdate.sync_aggregate.asTrusted(), # From DB, is trusted
forkyUpdate.signature_slot):
best[].reset() # Cached data is too recent or from other branch
else:
discard # Cached data is ancestor of `bid`
dag.cacheLightClientData(forkyState, forkyBlck,
current_period_best_update = best,
latest_signature_slot = GENESIS_SLOT)
else:
dag.createLightClientUpdate(
forkyState, forkyBlck, parentBid = blocks[i + 1])
else: raiseAssert "Unreachable"
# Import initial `LightClientBootstrap`
if dag.finalizedHead.slot >= dag.lcDataStore.cache.tailSlot:
if dag.createLightClientBootstrap(dag.finalizedHead.blck.bid).isErr:
dag.handleUnexpectedLightClientError(dag.finalizedHead.blck.bid.slot)
res.err()
let lightClientEndTick = Moment.now()
debug "Initialized cached LC data",
initDur = lightClientEndTick - lightClientStartTick, res
if res.isErr:
return
# Import historic data
if dag.lcDataStore.importMode == LightClientDataImportMode.Full:
dag.lcDataStore.cache.tailSlot = targetTailSlot
let targetTailPeriod = targetTailSlot.sync_committee_period
if targetTailPeriod < finalizedPeriod:
# `countdown` through 0 fails on distinct `uint64`
# https://github.com/nim-lang/Nim/pull/19926
var period = finalizedPeriod - 1
while period >= targetTailPeriod:
if dag.initLightClientDataForPeriod(period).isErr:
res.err()
if period <= targetTailPeriod:
break
dec period
debug "Historic LC data imported", res
proc processNewBlockForLightClient*(
dag: ChainDAGRef,
state: ForkedHashedBeaconState,
signedBlock: ForkyTrustedSignedBeaconBlock,
parentBid: BlockId) =
## Update light client data with information from a new block.
if not dag.shouldImportLcData:
return
if signedBlock.message.slot < dag.lcDataStore.cache.tailSlot:
return
const consensusFork = typeof(signedBlock).kind
when consensusFork >= ConsensusFork.Altair:
template forkyState: untyped = state.forky(consensusFork)
dag.createLightClientUpdate(forkyState, signedBlock, parentBid)
else:
raiseAssert "Unreachable" # `tailSlot` cannot be before Altair
proc processHeadChangeForLightClient*(dag: ChainDAGRef) =
## Update light client data to account for a new head block.
## Note that `dag.finalizedHead` is not yet updated when this is called.
if not dag.shouldImportLcData:
return
if dag.head.slot < dag.lcDataStore.cache.tailSlot:
return
# Commit best light client data for non-finalized periods
let
headPeriod = dag.head.slot.sync_committee_period
lowSlot = max(dag.lcDataStore.cache.tailSlot, dag.finalizedHead.slot)
lowPeriod = lowSlot.sync_committee_period
var blck = dag.head
for period in countdown(headPeriod, lowPeriod):
blck = blck.get_ancestor((period + 1).start_slot - 1)
if blck == nil or blck.slot < lowSlot:
break
dag.lcDataStore.db.putBestUpdate(
blck.slot.sync_committee_period,
dag.getLightClientData(blck.bid).current_period_best_update[])
# Update latest light client data
template latest(): untyped = dag.lcDataStore.cache.latest
let
head_data = dag.getLightClientData(dag.head.bid)
signature_slot = head_data.latest_signature_slot
if signature_slot <= lowSlot:
latest.reset()
return
blck = dag.head.get_ancestor(signature_slot)
if blck == nil or blck.parent == nil or blck.parent.slot < lowSlot:
# If `attested_bid` is before `finalizedHead`, we don't have cached data.
latest.reset()
return
let
signature_bid = blck.bid
attested_bid = blck.parent.bid
sync_aggregate = dag.getExistingSyncAggregate(signature_bid).valueOr:
dag.handleUnexpectedLightClientError(signature_bid.slot)
return
old_meta = latest.toMeta()
latest.assignLightClientData(
dag, attested_bid, signature_slot, sync_aggregate)
let
new_meta = latest.toMeta()
new_optimistic =
if new_meta.attested_slot != old_meta.attested_slot:
new_meta.attested_slot > old_meta.attested_slot
else:
new_meta.signature_slot > old_meta.signature_slot
new_finality =
if not new_meta.has_finality:
false
elif new_meta.finalized_slot != old_meta.finalized_slot:
new_meta.finalized_slot > old_meta.finalized_slot
else:
let
old_has_supermajority =
hasSupermajoritySyncParticipation(old_meta.num_active_participants)
new_has_supermajority =
hasSupermajoritySyncParticipation(new_meta.num_active_participants)
new_has_supermajority > old_has_supermajority
if new_finality and dag.lcDataStore.onLightClientFinalityUpdate != nil:
dag.lcDataStore.onLightClientFinalityUpdate(latest)
if new_optimistic and dag.lcDataStore.onLightClientOptimisticUpdate != nil:
dag.lcDataStore.onLightClientOptimisticUpdate(latest.toOptimistic())
proc processFinalizationForLightClient*(
dag: ChainDAGRef, oldFinalizedHead: BlockSlot) =
## Prune cached data that is no longer useful for creating future
## `LightClientUpdate` and `LightClientBootstrap` instances.
## This needs to be called whenever `finalized_checkpoint` changes.
if not dag.shouldImportLcData:
return
let finalizedSlot = dag.finalizedHead.slot
if finalizedSlot < dag.lcDataStore.cache.tailSlot:
return
# Cache `LightClientBootstrap` for newly finalized epoch boundary blocks
let
firstNewSlot = oldFinalizedHead.slot + 1
lowSlot = max(firstNewSlot, dag.lcDataStore.cache.tailSlot)
var boundarySlot = finalizedSlot
while boundarySlot >= lowSlot:
let
bsi = dag.getExistingBlockIdAtSlot(boundarySlot).valueOr:
dag.handleUnexpectedLightClientError(boundarySlot)
break
bid = bsi.bid
if bid.slot >= lowSlot:
if dag.createLightClientBootstrap(bid).isErr:
dag.handleUnexpectedLightClientError(bid.slot)
break
boundarySlot = bid.slot.nextEpochBoundarySlot
if boundarySlot < SLOTS_PER_EPOCH:
break
boundarySlot -= SLOTS_PER_EPOCH
# Seal sync committee periods for which data can no longer improve further
let
oldFinalizedPeriod = oldFinalizedHead.slot.sync_committee_period
newFinalizedPeriod = dag.finalizedHead.slot.sync_committee_period
if newFinalizedPeriod > oldFinalizedPeriod:
for period in countdown(newFinalizedPeriod - 1, oldFinalizedPeriod):
if dag.lcDataStore.cache.tailSlot > period.start_slot:
break
debug "Best LC update sealed",
period, update = dag.lcDataStore.db.getBestUpdate(period)
dag.lcDataStore.db.sealPeriod(period)
# Prune light client data that is no longer referrable by future updates
var bidsToDelete: seq[BlockId]
for bid, data in dag.lcDataStore.cache.data:
if bid.slot >= dag.finalizedHead.blck.slot:
continue
bidsToDelete.add bid
for bid in bidsToDelete:
dag.lcDataStore.cache.data.del bid
# Prune seal tracking data that is no longer relevant
let targetTailPeriod = dag.targetLightClientTailSlot.sync_committee_period
dag.lcDataStore.db.keepPeriodsFrom(targetTailPeriod)
proc getLightClientBootstrap(
dag: ChainDAGRef,
header: ForkyLightClientHeader): ForkedLightClientBootstrap =
let
slot = header.beacon.slot
period = slot.sync_committee_period
blockRoot = hash_tree_root(header)
if slot < dag.targetLightClientTailSlot:
debug "LC bootstrap unavailable: Block too old", slot
return default(ForkedLightClientBootstrap)
if slot > dag.finalizedHead.blck.slot:
debug "LC bootstrap unavailable: Not finalized", blockRoot
return default(ForkedLightClientBootstrap)
# Ensure `current_sync_committee_branch` is known
if dag.lcDataStore.importMode == LightClientDataImportMode.OnDemand and
not dag.lcDataStore.db.hasCurrentSyncCommitteeBranch(slot):
let
bsi = dag.getExistingBlockIdAtSlot(slot).valueOr:
return default(ForkedLightClientBootstrap)
tmpState = assignClone(dag.headState)
dag.withUpdatedExistingState(tmpState[], bsi) do:
withState(updatedState):
when consensusFork >= ConsensusFork.Altair:
if not dag.lcDataStore.db.hasSyncCommittee(period):
dag.lcDataStore.db.putSyncCommittee(
period, forkyState.data.current_sync_committee)
dag.lcDataStore.db.putHeader(header)
dag.lcDataStore.db.putCurrentSyncCommitteeBranch(
slot, forkyState.data.build_proof(
altair.CURRENT_SYNC_COMMITTEE_GINDEX).get)
else: raiseAssert "Unreachable"
do: return default(ForkedLightClientBootstrap)
# Ensure `current_sync_committee` is known
if not dag.lcDataStore.db.hasSyncCommittee(period):
let
tmpState = assignClone(dag.headState)
syncCommittee = dag.existingCurrentSyncCommitteeForPeriod(
tmpState[], period).valueOr:
return default(ForkedLightClientBootstrap)
dag.lcDataStore.db.putSyncCommittee(period, syncCommittee)
# Construct `LightClientBootstrap` from cached data
const lcDataFork = typeof(header).kind
ForkedLightClientBootstrap.init(lcDataFork.LightClientBootstrap(
header: header,
current_sync_committee: (block:
dag.lcDataStore.db.getSyncCommittee(period).valueOr:
debug "LC bootstrap unavailable: Sync committee not cached", period
return default(ForkedLightClientBootstrap)),
current_sync_committee_branch: (block:
dag.lcDataStore.db.getCurrentSyncCommitteeBranch(slot).valueOr:
debug "LC bootstrap unavailable: Committee branch not cached", slot
return default(ForkedLightClientBootstrap))))
proc getLightClientBootstrap*(
dag: ChainDAGRef,
blockRoot: Eth2Digest): ForkedLightClientBootstrap =
if not dag.lcDataStore.serve:
return default(ForkedLightClientBootstrap)
# Try to load from cache
withAll(LightClientDataFork):
when lcDataFork > LightClientDataFork.None:
let header = getHeader[lcDataFork.LightClientHeader](
dag.lcDataStore.db, blockRoot)
if header.isOk:
return dag.getLightClientBootstrap(header.get)
# Fallback to DAG
let bdata = dag.getForkedBlock(blockRoot).valueOr:
debug "LC bootstrap unavailable: Block not found", blockRoot
return default(ForkedLightClientBootstrap)
withBlck(bdata):
when consensusFork >= ConsensusFork.Altair:
const lcDataFork = lcDataForkAtConsensusFork(consensusFork)
let
header = forkyBlck.toLightClientHeader(lcDataFork)
bootstrap = dag.getLightClientBootstrap(header)
if bootstrap.kind > LightClientDataFork.None:
dag.lcDataStore.db.putHeader(header)
return bootstrap
else:
debug "LC bootstrap unavailable: Block before Altair", blockRoot
return default(ForkedLightClientBootstrap)
proc getLightClientUpdateForPeriod*(
dag: ChainDAGRef,
period: SyncCommitteePeriod): ForkedLightClientUpdate =
if not dag.lcDataStore.serve:
return default(ForkedLightClientUpdate)
if dag.lcDataStore.importMode == LightClientDataImportMode.OnDemand and
period < dag.finalizedHead.blck.slot.sync_committee_period:
if dag.initLightClientUpdateForPeriod(period).isErr:
return default(ForkedLightClientUpdate)
let
update = dag.lcDataStore.db.getBestUpdate(period)
numParticipants = withForkyUpdate(update):
when lcDataFork > LightClientDataFork.None:
forkyUpdate.sync_aggregate.num_active_participants
else:
0
if numParticipants < MIN_SYNC_COMMITTEE_PARTICIPANTS:
return default(ForkedLightClientUpdate)
update
proc getLightClientFinalityUpdate*(
dag: ChainDAGRef): ForkedLightClientFinalityUpdate =
if not dag.lcDataStore.serve:
return default(ForkedLightClientFinalityUpdate)
let
finalityUpdate = dag.lcDataStore.cache.latest
numParticipants = withForkyFinalityUpdate(finalityUpdate):
when lcDataFork > LightClientDataFork.None:
forkyFinalityUpdate.sync_aggregate.num_active_participants
else:
0
if numParticipants < MIN_SYNC_COMMITTEE_PARTICIPANTS:
return default(ForkedLightClientFinalityUpdate)
finalityUpdate
proc getLightClientOptimisticUpdate*(
dag: ChainDAGRef): ForkedLightClientOptimisticUpdate =
if not dag.lcDataStore.serve:
return default(ForkedLightClientOptimisticUpdate)
let
optimisticUpdate = dag.lcDataStore.cache.latest.toOptimistic
numParticipants = withForkyOptimisticUpdate(optimisticUpdate):
when lcDataFork > LightClientDataFork.None:
forkyOptimisticUpdate.sync_aggregate.num_active_participants
else:
0
if numParticipants < MIN_SYNC_COMMITTEE_PARTICIPANTS:
return default(ForkedLightClientOptimisticUpdate)
optimisticUpdate