nimbus-eth2/beacon_chain/consensus_object_pools/spec_cache.nim

232 lines
10 KiB
Nim

# beacon_chain
# Copyright (c) 2018-2022 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.
when (NimMajor, NimMinor) < (1, 4):
{.push raises: [Defect].}
else:
{.push raises: [].}
import
std/sequtils,
stew/results,
chronicles,
../extras,
../spec/[beaconstate, helpers, network, signatures, validator],
../spec/datatypes/base,
./block_pools_types, blockchain_dag
export
base, extras, block_pools_types, results
logScope: topics = "spec_cache"
# Spec functions implemented based on cached values instead of the full state
func count_active_validators*(shufflingRef: ShufflingRef): uint64 =
shufflingRef.shuffled_active_validator_indices.lenu64
# https://github.com/ethereum/consensus-specs/blob/v1.2.0-rc.3/specs/phase0/beacon-chain.md#get_committee_count_per_slot
func get_committee_count_per_slot*(shufflingRef: ShufflingRef): uint64 =
get_committee_count_per_slot(count_active_validators(shufflingRef))
iterator get_committee_indices*(shufflingRef: ShufflingRef): CommitteeIndex =
let committees_per_slot = get_committee_count_per_slot(shufflingRef)
for committee_index in get_committee_indices(committees_per_slot):
yield committee_index
func get_committee_index*(shufflingRef: ShufflingRef, index: uint64):
Result[CommitteeIndex, cstring] =
check_attestation_index(index, get_committee_count_per_slot(shufflingRef))
# https://github.com/ethereum/consensus-specs/blob/v1.2.0-rc.3/specs/phase0/beacon-chain.md#get_beacon_committee
iterator get_beacon_committee*(
shufflingRef: ShufflingRef, slot: Slot, committee_index: CommitteeIndex):
(int, ValidatorIndex) =
## Return the beacon committee at ``slot`` for ``index``.
doAssert slot.epoch == shufflingRef.epoch
let committees_per_slot = get_committee_count_per_slot(shufflingRef)
for index_in_committee, idx in compute_committee(
shufflingRef.shuffled_active_validator_indices,
(slot mod SLOTS_PER_EPOCH) * committees_per_slot + committee_index.asUInt64,
committees_per_slot * SLOTS_PER_EPOCH
): yield (index_in_committee, idx)
# https://github.com/ethereum/consensus-specs/blob/v1.2.0-rc.3/specs/phase0/beacon-chain.md#get_beacon_committee
func get_beacon_committee*(
shufflingRef: ShufflingRef, slot: Slot, committee_index: CommitteeIndex):
seq[ValidatorIndex] =
## Return the beacon committee at ``slot`` for ``index``.
doAssert slot.epoch == shufflingRef.epoch
let committees_per_slot = get_committee_count_per_slot(shufflingRef)
compute_committee(
shufflingRef.shuffled_active_validator_indices,
(slot mod SLOTS_PER_EPOCH) * committees_per_slot + committee_index.asUInt64,
committees_per_slot * SLOTS_PER_EPOCH
)
# https://github.com/ethereum/consensus-specs/blob/v1.2.0-rc.3/specs/phase0/beacon-chain.md#get_beacon_committee
func get_beacon_committee_len*(
shufflingRef: ShufflingRef, slot: Slot, committee_index: CommitteeIndex): uint64 =
## Return the number of members in the beacon committee at ``slot`` for ``index``.
doAssert slot.epoch == shufflingRef.epoch
let committees_per_slot = get_committee_count_per_slot(shufflingRef)
compute_committee_len(
count_active_validators(shufflingRef),
(slot mod SLOTS_PER_EPOCH) * committees_per_slot + committee_index.asUInt64,
committees_per_slot * SLOTS_PER_EPOCH
)
# https://github.com/ethereum/consensus-specs/blob/v1.2.0-rc.3/specs/phase0/beacon-chain.md#get_attesting_indices
iterator get_attesting_indices*(shufflingRef: ShufflingRef,
slot: Slot,
committee_index: CommitteeIndex,
bits: CommitteeValidatorsBits):
ValidatorIndex =
if bits.lenu64 != get_beacon_committee_len(shufflingRef, slot, committee_index):
trace "get_attesting_indices: inconsistent aggregation and committee length"
else:
for index_in_committee, validator_index in get_beacon_committee(
shufflingRef, slot, committee_index):
if bits[index_in_committee]:
yield validator_index
iterator get_attesting_indices*(
dag: ChainDAGRef, attestation: TrustedAttestation): ValidatorIndex =
block: # `return` is not allowed in an inline iterator
let
slot =
check_attestation_slot_target(attestation.data).valueOr:
warn "Invalid attestation slot"
doAssert strictVerification notin dag.updateFlags
break
blck =
dag.getBlockRef(attestation.data.beacon_block_root).valueOr:
# Attestation block unknown
break
target =
blck.atCheckpoint(attestation.data.target).valueOr:
warn "Invalid attestation target"
doAssert strictVerification notin dag.updateFlags
break
shufflingRef =
dag.getShufflingRef(target.blck, target.slot.epoch, false).valueOr:
warn "Attestation shuffling not found"
doAssert strictVerification notin dag.updateFlags
break
committeesPerSlot = get_committee_count_per_slot(shufflingRef)
committeeIndex =
CommitteeIndex.init(attestation.data.index, committeesPerSlot).valueOr:
warn "Unexpected committee index in block attestation"
doAssert strictVerification notin dag.updateFlags
break
for validator in get_attesting_indices(
shufflingRef, slot, committeeIndex, attestation.aggregation_bits):
yield validator
func get_attesting_indices_one*(shufflingRef: ShufflingRef,
slot: Slot,
committee_index: CommitteeIndex,
bits: CommitteeValidatorsBits):
Option[ValidatorIndex] =
# A variation on get_attesting_indices that returns the validator index only
# if only one validator index is set
var res = none(ValidatorIndex)
for validator_index in get_attesting_indices(
shufflingRef, slot, committee_index, bits):
if res.isSome(): return none(ValidatorIndex)
res = some(validator_index)
res
# https://github.com/ethereum/consensus-specs/blob/v1.2.0-rc.3/specs/phase0/beacon-chain.md#get_attesting_indices
func get_attesting_indices*(shufflingRef: ShufflingRef,
slot: Slot,
committee_index: CommitteeIndex,
bits: CommitteeValidatorsBits):
seq[ValidatorIndex] =
# TODO sequtils2 mapIt
for idx in get_attesting_indices(shufflingRef, slot, committee_index, bits):
result.add(idx)
# https://github.com/ethereum/consensus-specs/blob/v1.2.0-rc.3/specs/phase0/beacon-chain.md#is_valid_indexed_attestation
proc is_valid_indexed_attestation*(
fork: Fork, genesis_validators_root: Eth2Digest,
dag: ChainDAGRef, shufflingRef: EpochRef,
attestation: SomeAttestation, flags: UpdateFlags): Result[void, cstring] =
# This is a variation on `is_valid_indexed_attestation` that works directly
# with an attestation instead of first constructing an `IndexedAttestation`
# and then validating it - for the purpose of validating the signature, the
# order doesn't matter and we can proceed straight to validating the
# signature instead
let sigs = attestation.aggregation_bits.countOnes()
if sigs == 0:
return err("is_valid_indexed_attestation: no attesting indices")
# Verify aggregate signature
if not (skipBlsValidation in flags or attestation.signature is TrustedSig):
var
pubkeys = newSeqOfCap[CookedPubKey](sigs)
for index in get_attesting_indices(
shufflingRef, attestation.data, attestation.aggregation_bits):
pubkeys.add(dag.validatorKey(index).get())
if not verify_attestation_signature(
fork, genesis_validators_root, attestation.data,
pubkeys, attestation.signature):
return err("is_valid_indexed_attestation: signature verification failure")
ok()
func makeAttestationData*(
epochRef: EpochRef, bs: BlockSlot,
committee_index: CommitteeIndex): AttestationData =
## Create an attestation / vote for the block `bs` using the
## data in `epochRef` to fill in the rest of the fields.
## `epochRef` is the epoch information corresponding to the `bs` advanced to
## the slot we're attesting to.
let
slot = bs.slot
current_epoch = slot.epoch()
epoch_boundary_slot = current_epoch.start_slot()
epoch_boundary_block = bs.blck.atSlot(epoch_boundary_slot)
doAssert current_epoch == epochRef.epoch
# https://github.com/ethereum/consensus-specs/blob/v1.2.0-rc.1/specs/phase0/validator.md#attestation-data
AttestationData(
slot: slot,
index: committee_index.asUInt64,
beacon_block_root: bs.blck.root,
source: epochRef.checkpoints.justified,
target: Checkpoint(
epoch: current_epoch,
root: epoch_boundary_block.blck.root))
# https://github.com/ethereum/consensus-specs/blob/v1.2.0-rc.1/specs/phase0/validator.md#validator-assignments
iterator get_committee_assignments*(
shufflingRef: ShufflingRef, validator_indices: HashSet[ValidatorIndex]):
tuple[committee_index: CommitteeIndex,
subnet_id: SubnetId, slot: Slot] =
let
committees_per_slot = get_committee_count_per_slot(shufflingRef)
epoch = shufflingRef.epoch
for slot in epoch.slots():
for committee_index in get_committee_indices(committees_per_slot):
if anyIt(get_beacon_committee(shufflingRef, slot, committee_index), it in validator_indices):
yield (
committee_index,
compute_subnet_for_attestation(committees_per_slot, slot, committee_index),
slot)
func is_aggregator*(shufflingRef: ShufflingRef, slot: Slot,
index: CommitteeIndex, slot_signature: ValidatorSig): bool =
let
committee_len = get_beacon_committee_len(shufflingRef, slot, index)
return is_aggregator(committee_len, slot_signature)