291 lines
9.9 KiB
Nim
291 lines
9.9 KiB
Nim
# beacon_chain
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# Copyright (c) 2018-2022 Status Research & Development GmbH
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# Licensed and distributed under either of
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# * MIT license (license terms in the root directory or at https://opensource.org/licenses/MIT).
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# * Apache v2 license (license terms in the root directory or at https://www.apache.org/licenses/LICENSE-2.0).
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# at your option. This file may not be copied, modified, or distributed except according to those terms.
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{.push raises: [Defect].}
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import
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std/[sets, tables],
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stew/shims/hashes,
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bearssl,
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eth/p2p/discoveryv5/random2,
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chronicles,
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../spec/[crypto, digest],
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../spec/datatypes/altair
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export hashes, sets, tables, altair
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const
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syncCommitteeMsgsRetentionSlots = 3
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## How many slots to retain sync committee
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## messsages before discarding them.
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type
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SyncCommitteeMsgKey = object
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originator: uint64 # ValidatorIndex avoiding mess with invalid values
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slot: Slot
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subcommitteeIdx: uint64 # SyncSubcommitteeIndex avoiding mess with invalid values
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TrustedSyncCommitteeMsg* = object
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slot*: Slot
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subcommitteeIdx*: SyncSubcommitteeIndex
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positionInCommittee*: uint64
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signature*: CookedSig
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BestSyncSubcommitteeContribution* = object
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totalParticipants*: int
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participationBits*: SyncCommitteeAggregationBits
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signature*: CookedSig
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BestSyncSubcommitteeContributions* = object
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slot*: Slot
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subnets*: array[SYNC_COMMITTEE_SUBNET_COUNT,
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BestSyncSubcommitteeContribution]
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OnSyncContributionCallback* =
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proc(data: SignedContributionAndProof) {.gcsafe, raises: [Defect].}
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SyncCommitteeMsgPool* = object
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seenSyncMsgByAuthor*: HashSet[SyncCommitteeMsgKey]
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seenContributionByAuthor*: HashSet[SyncCommitteeMsgKey]
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syncMessages*: Table[Eth2Digest, seq[TrustedSyncCommitteeMsg]]
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bestContributions*: Table[Eth2Digest, BestSyncSubcommitteeContributions]
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onContributionReceived*: OnSyncContributionCallback
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rng: ref BrHmacDrbgContext
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syncCommitteeSubscriptions*: Table[ValidatorPubKey, Epoch]
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func hash*(x: SyncCommitteeMsgKey): Hash =
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hashAllFields(x)
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func init*(T: type SyncCommitteeMsgPool,
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rng: ref BrHmacDrbgContext,
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onSyncContribution: OnSyncContributionCallback = nil
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): SyncCommitteeMsgPool =
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T(rng: rng, onContributionReceived: onSyncContribution)
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func pruneData*(pool: var SyncCommitteeMsgPool, slot: Slot) =
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## This should be called at the end of slot.
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clear pool.seenContributionByAuthor
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clear pool.seenSyncMsgByAuthor
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if slot < syncCommitteeMsgsRetentionSlots:
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return
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let minSlotToRetain = slot - syncCommitteeMsgsRetentionSlots
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var syncMsgsToDelete: seq[Eth2Digest]
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var contributionsToDelete: seq[Eth2Digest]
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for blockRoot, msgs in pool.syncMessages:
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if msgs[0].slot < minSlotToRetain:
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syncMsgsToDelete.add blockRoot
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for blockRoot in syncMsgsToDelete:
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pool.syncMessages.del blockRoot
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for blockRoot, bestContributions in pool.bestContributions:
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if bestContributions.slot < minSlotToRetain:
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contributionsToDelete.add blockRoot
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for blockRoot in contributionsToDelete:
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pool.bestContributions.del blockRoot
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func isSeen*(
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pool: SyncCommitteeMsgPool,
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msg: SyncCommitteeMessage,
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subcommitteeIdx: SyncSubcommitteeIndex): bool =
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let seenKey = SyncCommitteeMsgKey(
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originator: msg.validator_index, # Might be unvalidated at this point
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slot: msg.slot,
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subcommitteeIdx: subcommitteeIdx.uint64)
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seenKey in pool.seenSyncMsgByAuthor
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proc addSyncCommitteeMessage*(
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pool: var SyncCommitteeMsgPool,
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slot: Slot,
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blockRoot: Eth2Digest,
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validatorIndex: uint64,
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signature: CookedSig,
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subcommitteeIdx: SyncSubcommitteeIndex,
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positionsInCommittee: openArray[uint64]) =
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let
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seenKey = SyncCommitteeMsgKey(
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originator: validatorIndex,
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slot: slot,
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subcommitteeIdx: subcommitteeIdx.uint64)
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pool.seenSyncMsgByAuthor.incl seenKey
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for position in positionsInCommittee:
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pool.syncMessages.mgetOrPut(blockRoot, @[]).add TrustedSyncCommitteeMsg(
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slot: slot,
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subcommitteeIdx: subcommitteeIdx,
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positionInCommittee: position,
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signature: signature)
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debug "Sync committee message resolved",
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slot = slot, blockRoot = shortLog(blockRoot), validatorIndex
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func computeAggregateSig(votes: seq[TrustedSyncCommitteeMsg],
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subcommitteeIdx: SyncSubcommitteeIndex,
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contribution: var SyncCommitteeContribution): bool =
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var
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aggregateSig {.noInit.}: AggregateSignature
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initialized = false
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for vote in votes:
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if vote.subcommitteeIdx != subcommitteeIdx:
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continue
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if not contribution.aggregation_bits[vote.positionInCommittee]:
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if not initialized:
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initialized = true
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aggregateSig.init(vote.signature)
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else:
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aggregateSig.aggregate(vote.signature)
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contribution.aggregation_bits.setBit vote.positionInCommittee
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if initialized:
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contribution.signature = aggregateSig.finish.toValidatorSig
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return initialized
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func produceContribution*(
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pool: SyncCommitteeMsgPool,
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slot: Slot,
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headRoot: Eth2Digest,
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subcommitteeIdx: SyncSubcommitteeIndex,
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outContribution: var SyncCommitteeContribution): bool =
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if headRoot in pool.syncMessages:
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outContribution.slot = slot
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outContribution.beacon_block_root = headRoot
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outContribution.subcommittee_index = subcommitteeIdx.asUInt64
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try:
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computeAggregateSig(pool.syncMessages[headRoot],
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subcommitteeIdx,
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outContribution)
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except KeyError:
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raiseAssert "We have checked for the key upfront"
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else:
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false
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func addAggregateAux(bestVotes: var BestSyncSubcommitteeContributions,
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contribution: SyncCommitteeContribution) =
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let
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currentBestTotalParticipants =
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bestVotes.subnets[contribution.subcommittee_index].totalParticipants
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newBestTotalParticipants = countOnes(contribution.aggregation_bits)
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if newBestTotalParticipants > currentBestTotalParticipants:
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bestVotes.subnets[contribution.subcommittee_index] =
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BestSyncSubcommitteeContribution(
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totalParticipants: newBestTotalParticipants,
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participationBits: contribution.aggregation_bits,
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signature: contribution.signature.load.get)
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func isSeen*(
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pool: SyncCommitteeMsgPool,
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msg: ContributionAndProof): bool =
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let seenKey = SyncCommitteeMsgKey(
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originator: msg.aggregator_index,
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slot: msg.contribution.slot,
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subcommitteeIdx: msg.contribution.subcommittee_index)
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seenKey in pool.seenContributionByAuthor
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proc addContribution(pool: var SyncCommitteeMsgPool,
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aggregator_index: uint64,
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contribution: SyncCommitteeContribution,
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signature: CookedSig) =
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let seenKey = SyncCommitteeMsgKey(
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originator: aggregator_index,
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slot: contribution.slot,
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subcommitteeIdx: contribution.subcommittee_index)
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pool.seenContributionByAuthor.incl seenKey
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template blockRoot: auto = contribution.beacon_block_root
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if blockRoot notin pool.bestContributions:
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let totalParticipants = countOnes(contribution.aggregation_bits)
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var initialBestContributions = BestSyncSubcommitteeContributions(
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slot: contribution.slot)
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initialBestContributions.subnets[contribution.subcommittee_index] =
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BestSyncSubcommitteeContribution(
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totalParticipants: totalParticipants,
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participationBits: contribution.aggregation_bits,
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signature: signature)
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pool.bestContributions[blockRoot] = initialBestContributions
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else:
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try:
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addAggregateAux(pool.bestContributions[blockRoot], contribution)
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except KeyError:
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raiseAssert "We have checked for the key upfront"
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proc addContribution*(pool: var SyncCommitteeMsgPool,
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scproof: SignedContributionAndProof,
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signature: CookedSig) =
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pool.addContribution(
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scproof.message.aggregator_index, scproof.message.contribution, signature)
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if not(isNil(pool.onContributionReceived)):
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pool.onContributionReceived(scproof)
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proc produceSyncAggregateAux(
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bestContributions: BestSyncSubcommitteeContributions): SyncAggregate =
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var
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aggregateSig {.noInit.}: AggregateSignature
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initialized = false
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startTime = Moment.now
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for subcommitteeIdx in SyncSubcommitteeIndex:
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if bestContributions.subnets[subcommitteeIdx].totalParticipants == 0:
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continue
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for pos, value in bestContributions.subnets[subcommitteeIdx].participationBits:
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if value:
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let globalPos = subcommitteeIdx.asInt * SYNC_SUBCOMMITTEE_SIZE + pos
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result.sync_committee_bits.setBit globalPos
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if not initialized:
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initialized = true
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aggregateSig.init(bestContributions.subnets[subcommitteeIdx].signature)
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else:
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aggregateSig.aggregate(bestContributions.subnets[subcommitteeIdx].signature)
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if initialized:
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result.sync_committee_signature = aggregateSig.finish.toValidatorSig
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else:
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result.sync_committee_signature = ValidatorSig.infinity
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let duration = Moment.now - startTime
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debug "SyncAggregate produced", duration,
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bits = result.sync_committee_bits
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proc produceSyncAggregate*(
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pool: SyncCommitteeMsgPool,
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targetRoot: Eth2Digest): SyncAggregate =
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if targetRoot in pool.bestContributions:
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try:
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produceSyncAggregateAux(pool.bestContributions[targetRoot])
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except KeyError:
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raiseAssert "We have checked for the key upfront"
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else:
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SyncAggregate.init()
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proc isEpochLeadTime*(
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pool: SyncCommitteeMsgPool, epochsToSyncPeriod: uint64): bool =
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# https://github.com/ethereum/consensus-specs/blob/v1.1.9/specs/altair/validator.md#sync-committee-subnet-stability
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# This ensures a uniform distribution without requiring additional state:
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# (1/4) = 1/4, 4 slots out
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# (3/4) * (1/3) = 1/4, 3 slots out
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# (3/4) * (2/3) * (1/2) = 1/4, 2 slots out
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# (3/4) * (2/3) * (1/2) * (1/1) = 1/4, 1 slot out
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doAssert epochsToSyncPeriod > 0
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epochsToSyncPeriod == 1 or pool.rng[].rand(epochsToSyncPeriod - 1) == 0
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