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

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Nim

# beacon_chain
# Copyright (c) 2022-2023 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.isErr:
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.isErr:
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.isErr:
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.isErr:
error "Current sync committee failed to load unexpectedly",
period, tail = dag.tail.slot
doAssert strictVerification notin dag.updateFlags
syncCommittee
template syncCommitteeRoot(state: ForkyHashedBeaconState): Eth2Digest =
## Compute a root to uniquely identify `current_sync_committee` and
## `next_sync_committee`.
withEth2Hash:
h.update state.data.current_sync_committee.hash_tree_root().data
h.update state.data.next_sync_committee.hash_tree_root().data
proc syncCommitteeRootForPeriod(
dag: ChainDAGRef,
tmpState: var ForkedHashedBeaconState,
period: SyncCommitteePeriod): Opt[Eth2Digest] =
## Compute a root to uniquely identify `current_sync_committee` and
## `next_sync_committee` for a given sync committee period.
## For non-finalized periods, follow the chain as selected by fork choice.
let lowSlot = max(dag.tail.slot, dag.cfg.ALTAIR_FORK_EPOCH.start_slot)
if period < lowSlot.sync_committee_period:
return err()
let
periodStartSlot = period.start_slot
syncCommitteeSlot = max(periodStartSlot, lowSlot)
bsi = ? dag.getExistingBlockIdAtSlot(syncCommitteeSlot)
dag.withUpdatedExistingState(tmpState, bsi) do:
withState(updatedState):
when consensusFork >= ConsensusFork.Altair:
ok forkyState.syncCommitteeRoot
else: raiseAssert "Unreachable"
do: err()
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, bid: BlockId,
current_period_best_update: ref ForkedLightClientUpdate) =
## 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 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)
if dag.lcDataStore.cache.data.hasKeyOrPut(bid, cachedData):
doAssert false, "Redundant `cacheLightClientData` call"
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
template lazy_header(name: untyped): untyped {.dirty.} =
## `createLightClientUpdates` helper to lazily load a known block header.
var
`name _ ptr`: ptr[data_fork.LightClientHeader]
`name _ ok` = true
template `assign _ name`(
obj: var SomeForkyLightClientObject, bid: BlockId): untyped {.used.} =
if `name _ ptr` != nil:
obj.name = `name _ ptr`[]
elif `name _ ok`:
let bdata = dag.getExistingForkedBlock(bid)
if bdata.isErr:
dag.handleUnexpectedLightClientError(bid.slot)
`name _ ok` = false
else:
withBlck(bdata.get):
when data_fork >= lcDataForkAtConsensusFork(consensusFork):
obj.name = forkyBlck.toLightClientHeader(data_fork)
else: raiseAssert "Unreachable"
`name _ ptr` = addr obj.name
`name _ ok`
template `assign _ name _ with_migration`(
obj: var SomeForkedLightClientObject, bid: BlockId): untyped {.used.} =
if `name _ ptr` != nil:
obj.migrateToDataFork(data_fork)
obj.forky(data_fork).name = `name _ ptr`[]
elif `name _ ok`:
let bdata = dag.getExistingForkedBlock(bid)
if bdata.isErr:
dag.handleUnexpectedLightClientError(bid.slot)
`name _ ok` = false
else:
obj.migrateToDataFork(data_fork)
withBlck(bdata.get):
when data_fork >= lcDataForkAtConsensusFork(consensusFork):
obj.forky(data_fork).name = forkyBlck.toLightClientHeader(data_fork)
else: raiseAssert "Unreachable"
`name _ ptr` = addr obj.forky(data_fork).name
`name _ ok`
template lazy_bid(name: untyped): untyped {.dirty.} =
## `createLightClientUpdates` helper to lazily load a known to exist block id.
var
`name` {.noinit.}: BlockId
`name _ ok` = true
`name`.slot = FAR_FUTURE_SLOT
template `load _ name`(slot: Slot): bool =
if `name _ ok` and `name`.slot == FAR_FUTURE_SLOT:
let bsi = dag.getExistingBlockIdAtSlot(slot)
if bsi.isErr:
dag.handleUnexpectedLightClientError(slot)
`name _ ok` = false
else:
`name` = bsi.get.bid
`name _ ok`
proc createLightClientUpdates(
dag: ChainDAGRef,
state: ForkyHashedBeaconState,
blck: ForkyTrustedSignedBeaconBlock,
parent_bid: BlockId,
data_fork: static LightClientDataFork): ref ForkedLightClientUpdate =
## 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.
## Returns the best `LightClientUpdate` for the block's sync committee period.
# 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:
return (ref ForkedLightClientUpdate)()
# `blck` and `parent_bid` must be in the same sync committee period
# to update the best per-period `LightClientUpdate`
let
attested_period = attested_slot.sync_committee_period
signature_slot = blck.message.slot
signature_period = signature_slot.sync_committee_period
var
attested_data = dag.getLightClientData(attested_bid)
best =
if attested_period != signature_period:
(ref ForkedLightClientUpdate)()
else:
attested_data.current_period_best_update
# Verify sync committee has sufficient participants
template sync_aggregate(): auto = blck.asSigned().message.body.sync_aggregate
let num_active_participants = sync_aggregate.num_active_participants.uint64
if num_active_participants < MIN_SYNC_COMMITTEE_PARTICIPANTS:
return best
# Lazy variables to hold historic data
lazy_header(attested_header)
lazy_bid(finalized_bid)
lazy_header(finalized_header)
# Update latest light client data
template latest(): untyped = dag.lcDataStore.cache.latest
var
newFinality = false
newOptimistic = false
let is_later = withForkyFinalityUpdate(latest):
when lcDataFork > LightClientDataFork.None:
if attested_slot != forkyFinalityUpdate.attested_header.beacon.slot:
attested_slot > forkyFinalityUpdate.attested_header.beacon.slot
else:
signature_slot > forkyFinalityUpdate.signature_slot
else:
true
if is_later and latest.assign_attested_header_with_migration(attested_bid):
template forkyLatest: untyped = latest.forky(data_fork)
var finalized_slot = attested_data.finalized_slot
if finalized_slot == forkyLatest.finalized_header.beacon.slot:
forkyLatest.finality_branch = attested_data.finality_branch
let old_num_active_participants =
forkyLatest.sync_aggregate.num_active_participants.uint64
if not hasSupermajoritySyncParticipation(old_num_active_participants) and
hasSupermajoritySyncParticipation(num_active_participants):
newFinality = true
elif finalized_slot < dag.tail.slot or
not load_finalized_bid(finalized_slot):
forkyLatest.finalized_header.reset()
forkyLatest.finality_branch.reset()
else:
if finalized_bid.slot != finalized_slot:
finalized_slot = finalized_bid.slot
attested_data.finalized_slot = finalized_slot
dag.lcDataStore.cache.data[attested_bid] = attested_data
if finalized_slot == forkyLatest.finalized_header.beacon.slot:
forkyLatest.finality_branch = attested_data.finality_branch
elif finalized_slot == GENESIS_SLOT:
forkyLatest.finalized_header.reset()
forkyLatest.finality_branch = attested_data.finality_branch
elif forkyLatest.assign_finalized_header(finalized_bid):
forkyLatest.finality_branch = attested_data.finality_branch
newFinality = true
else:
forkyLatest.finalized_header.reset()
forkyLatest.finality_branch.reset()
forkyLatest.sync_aggregate = sync_aggregate
forkyLatest.signature_slot = signature_slot
newOptimistic = true
# Track best light client data for current period
if attested_period == signature_period:
let
finalized_slot = attested_data.finalized_slot
has_finality =
finalized_slot >= dag.tail.slot and load_finalized_bid(finalized_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 is_better:
best = newClone attested_data.current_period_best_update[]
if not best[].assign_attested_header_with_migration(attested_bid):
best = attested_data.current_period_best_update
else:
template forkyBest: untyped = best[].forky(data_fork)
forkyBest.next_sync_committee = state.data.next_sync_committee
forkyBest.next_sync_committee_branch =
attested_data.next_sync_committee_branch
if finalized_slot == forkyBest.finalized_header.beacon.slot:
forkyBest.finality_branch = attested_data.finality_branch
elif finalized_slot == GENESIS_SLOT:
forkyBest.finalized_header.reset()
forkyBest.finality_branch = attested_data.finality_branch
elif has_finality and
forkyBest.assign_finalized_header(finalized_bid):
forkyBest.finality_branch = attested_data.finality_branch
else:
forkyBest.finalized_header.reset()
forkyBest.finality_branch.reset()
forkyBest.sync_aggregate = sync_aggregate
forkyBest.signature_slot = signature_slot
debug "Best LC update improved",
period = attested_period, update = forkyBest
if newFinality and dag.lcDataStore.onLightClientFinalityUpdate != nil:
dag.lcDataStore.onLightClientFinalityUpdate(latest)
if newOptimistic and dag.lcDataStore.onLightClientOptimisticUpdate != nil:
dag.lcDataStore.onLightClientOptimisticUpdate(latest.toOptimistic)
best
proc createLightClientUpdates(
dag: ChainDAGRef,
state: ForkyHashedBeaconState,
blck: ForkyTrustedSignedBeaconBlock,
parent_bid: BlockId) =
# Attested block (parent) determines `LightClientUpdate` fork
let best = withLcDataFork(dag.cfg.lcDataForkAtEpoch(parent_bid.slot.epoch)):
when lcDataFork > LightClientDataFork.None:
dag.createLightClientUpdates(state, blck, parent_bid, lcDataFork)
else:
(ref ForkedLightClientUpdate)()
dag.cacheLightClientData(state, blck.toBlockId(), best)
proc initLightClientDataCache*(dag: ChainDAGRef) =
## Initialize cached light client data
if not dag.shouldImportLcData:
return
# Initialize tail slot
let targetTailSlot = max(dag.targetLightClientTailSlot, dag.tail.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
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 block 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, bid, best)
else:
dag.createLightClientUpdates(
forkyState, forkyBlck, parentBid = blocks[i + 1])
else: raiseAssert "Unreachable"
let lightClientEndTick = Moment.now()
debug "Initialized cached LC data",
initDur = lightClientEndTick - lightClientStartTick, res
if res.isErr:
return
if dag.lcDataStore.importMode == LightClientDataImportMode.OnDemand:
return
# Import historic data
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.createLightClientUpdates(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
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:
return
if blck.slot < lowSlot:
return
dag.lcDataStore.db.putBestUpdate(
blck.slot.sync_committee_period,
dag.getLightClientData(blck.bid).current_period_best_update[])
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:
let
bdata = dag.getExistingForkedBlock(bid).valueOr:
dag.handleUnexpectedLightClientError(bid.slot)
break
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).valueOr:
dag.handleUnexpectedLightClientError(bid.slot)
break
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)
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