nimbus-eth2/beacon_chain/statediff.nim

280 lines
11 KiB
Nim

# beacon_chain
# Copyright (c) 2020-2023 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
stew/assign2,
./spec/forks
func diffModIncEpoch[T, U](hl: HashArray[U, T], startSlot: uint64):
array[SLOTS_PER_EPOCH, T] =
static: doAssert U.uint64 mod SLOTS_PER_EPOCH == 0
doAssert startSlot mod SLOTS_PER_EPOCH == 0
for i in startSlot ..< startSlot + SLOTS_PER_EPOCH:
result[i mod SLOTS_PER_EPOCH] = hl[i mod U.uint64]
func applyModIncrement[T, U](
ha: var HashArray[U, T], hl: array[SLOTS_PER_EPOCH, T], slot: uint64) =
var indexSlot = slot
for item in hl:
ha[indexSlot mod U.uint64] = item
indexSlot += 1
func applyValidatorIdentities(
validators: var HashList[Validator, Limit VALIDATOR_REGISTRY_LIMIT],
hl: auto) =
for item in hl:
if not validators.add Validator(
pubkey: item.pubkey.toPubKey(),
withdrawal_credentials: item.withdrawal_credentials):
raiseAssert "cannot readd"
func setValidatorStatusesNoWithdrawals(
validators: var HashList[Validator, Limit VALIDATOR_REGISTRY_LIMIT],
hl: List[ValidatorStatus, Limit VALIDATOR_REGISTRY_LIMIT]) =
doAssert validators.len == hl.len
for i in 0 ..< hl.len:
let validator = addr validators.mitem(i)
validator[].effective_balance = hl[i].effective_balance
validator[].slashed = hl[i].slashed
validator[].activation_eligibility_epoch =
hl[i].activation_eligibility_epoch
validator[].activation_epoch = hl[i].activation_epoch
validator[].exit_epoch = hl[i].exit_epoch
validator[].withdrawable_epoch = hl[i].withdrawable_epoch
func replaceOrAddEncodeEth1Votes[T, U](
votes0: openArray[T], votes0_len: int, votes1: HashList[T, U]):
(bool, List[T, U]) =
let
num_votes0 = votes0.len
lower_bound =
if votes1.len < num_votes0 or
(num_votes0 > 0 and votes0[num_votes0 - 1] != votes1[num_votes0 - 1]):
# EPOCHS_PER_ETH1_VOTING_PERIOD epochs have passed, and
# eth1_data_votes has been reset/cleared. Because their
# deposit_index counts increase monotonically, it works
# to use only the last element for comparison.
0
else:
num_votes0
var res = (lower_bound == 0, default(List[T, U]))
for i in lower_bound ..< votes1.len:
if not result[1].add votes1[i]:
raiseAssert "same limit"
res
func replaceOrAddDecodeEth1Votes[T, U](
votes0: var HashList[T, U], eth1_data_votes_replaced: bool,
votes1: List[T, U]) =
if eth1_data_votes_replaced:
votes0 = HashList[T, U]()
for item in votes1:
if not votes0.add item:
raiseAssert "same limit"
func getMutableValidatorStatuses(state: capella.BeaconState):
List[ValidatorStatus, Limit VALIDATOR_REGISTRY_LIMIT] =
if not result.setLen(state.validators.len):
raiseAssert "same limit as validators"
for i in 0 ..< state.validators.len:
let validator = unsafeAddr state.validators.data[i]
assign(result[i].effective_balance, validator.effective_balance)
assign(result[i].slashed, validator.slashed)
assign(
result[i].activation_eligibility_epoch,
validator.activation_eligibility_epoch)
assign(result[i].activation_epoch, validator.activation_epoch)
assign(result[i].exit_epoch, validator.exit_epoch)
assign(result[i].withdrawable_epoch, validator.withdrawable_epoch)
from "."/spec/beaconstate import has_eth1_withdrawal_credential
func getValidatorWithdrawalChanges(
presummary: BeaconStateDiffPreSnapshot, state: capella.BeaconState):
List[IndexedWithdrawalCredentials, Limit VALIDATOR_REGISTRY_LIMIT] =
# The only possible change is a one-time-per-validator change from BLS to
# execution withdrawal credentials, within the scope of Capella.
var res: List[IndexedWithdrawalCredentials, Limit VALIDATOR_REGISTRY_LIMIT]
for i in 0 ..< state.validators.lenu64:
if state.validators.item(i).has_eth1_withdrawal_credential and
not presummary.eth1_withdrawal_credential[i]:
if not res.add IndexedWithdrawalCredentials(
validator_index: i,
withdrawal_credentials:
state.validators.item(i).withdrawal_credentials):
raiseAssert "same limit as validators"
res
func diffStates*(
state0: BeaconStateDiffPreSnapshot, state1: capella.BeaconState):
BeaconStateDiff =
let
historical_summary_added =
state0.historical_summaries_len != state1.historical_summaries.len
(eth1_data_votes_replaced, eth1_data_votes) =
replaceOrAddEncodeEth1Votes(
state0.eth1_data_votes_recent, state0.eth1_data_votes_len,
state1.eth1_data_votes)
BeaconStateDiff(
slot: state1.slot,
latest_block_header: state1.latest_block_header,
block_roots: diffModIncEpoch(state1.block_roots, state0.slot.uint64),
state_roots: diffModIncEpoch(state1.state_roots, state0.slot.uint64),
eth1_data: state1.eth1_data,
eth1_data_votes_replaced: eth1_data_votes_replaced,
eth1_data_votes: eth1_data_votes,
eth1_deposit_index: state1.eth1_deposit_index,
validator_statuses: getMutableValidatorStatuses(state1),
withdrawal_credential_changes:
getValidatorWithdrawalChanges(state0, state1),
balances: state1.balances.data,
# RANDAO mixes gets updated every block, in place
randao_mix: state1.randao_mixes[state0.slot.epoch.uint64 mod
EPOCHS_PER_HISTORICAL_VECTOR.uint64],
slashing: state1.slashings[state0.slot.epoch.uint64 mod
EPOCHS_PER_HISTORICAL_VECTOR.uint64],
previous_epoch_participation: state1.previous_epoch_participation,
current_epoch_participation: state1.current_epoch_participation,
justification_bits: state1.justification_bits,
previous_justified_checkpoint: state1.previous_justified_checkpoint,
current_justified_checkpoint: state1.current_justified_checkpoint,
finalized_checkpoint: state1.finalized_checkpoint,
inactivity_scores: state1.inactivity_scores.data,
current_sync_committee: state1.current_sync_committee,
next_sync_committee: state1.next_sync_committee,
latest_execution_payload_header: state1.latest_execution_payload_header,
next_withdrawal_index: state1.next_withdrawal_index,
next_withdrawal_validator_index: state1.next_withdrawal_validator_index,
historical_summary_added: historical_summary_added,
historical_summary:
if historical_summary_added:
state1.historical_summaries[state0.historical_summaries_len]
else:
(static(default(HistoricalSummary)))
)
from std/sequtils import mapIt
func getBeaconStateDiffSummary*(state0: capella.BeaconState):
BeaconStateDiffPreSnapshot =
BeaconStateDiffPreSnapshot(
eth1_data_votes_recent:
if state0.eth1_data_votes.len > 0:
# replaceOrAddEncodeEth1Votes will check whether it needs to replace or add
# the votes. Which happens is a function of effectively external data, i.e.
# https://github.com/ethereum/consensus-specs/blob/v1.4.0-alpha.0/specs/phase0/beacon-chain.md#eth1-data
# notes it depends on things not deterministic, from a pure consensus-layer
# perspective. It thus must distinguish between adding and replacing votes,
# which it accomplishes by checking lengths and the most recent votes. This
# enables it to disambiguate when, for example, the number of Eth1 votes in
# both states is identical, but they're distinct because they were replaced
# between said states. This should not be feasible for the usual, intended,
# use case of exactly one epoch strides, but avoids a design coupling while
# not adding much runtime or storage cost.
state0.eth1_data_votes[^1 .. ^1]
else:
@[],
eth1_data_votes_len: state0.eth1_data_votes.len,
slot: state0.slot,
historical_summaries_len: state0.historical_summaries.len,
eth1_withdrawal_credential:
mapIt(state0.validators, it.has_eth1_withdrawal_credential))
func applyDiff*(
state: var capella.BeaconState,
immutableValidators: openArray[ImmutableValidatorData2],
stateDiff: BeaconStateDiff) =
template assign[T, U](tgt: var HashList[T, U], src: List[T, U]) =
assign(tgt.data, src)
tgt.resetCache()
# Carry over unchanged genesis_time, genesis_validators_root, and fork.
assign(state.latest_block_header, stateDiff.latest_block_header)
applyModIncrement(state.block_roots, stateDiff.block_roots, state.slot.uint64)
applyModIncrement(state.state_roots, stateDiff.state_roots, state.slot.uint64)
# Capella freezes historical_roots
assign(state.eth1_data, stateDiff.eth1_data)
replaceOrAddDecodeEth1Votes(
state.eth1_data_votes, stateDiff.eth1_data_votes_replaced,
stateDiff.eth1_data_votes)
assign(state.eth1_deposit_index, stateDiff.eth1_deposit_index)
applyValidatorIdentities(state.validators, immutableValidators)
setValidatorStatusesNoWithdrawals(
state.validators, stateDiff.validator_statuses)
for withdrawalUpdate in stateDiff.withdrawal_credential_changes:
assign(
state.validators.mitem(
withdrawalUpdate.validator_index).withdrawal_credentials,
withdrawalUpdate.withdrawal_credentials)
assign(state.balances, stateDiff.balances)
# RANDAO mixes gets updated every block, in place, so ensure there's always
# >=1 value from it
let epochIndex =
state.slot.epoch.uint64 mod EPOCHS_PER_HISTORICAL_VECTOR.uint64
assign(state.randao_mixes.mitem(epochIndex), stateDiff.randao_mix)
assign(state.slashings.mitem(epochIndex), stateDiff.slashing)
assign(
state.previous_epoch_participation, stateDiff.previous_epoch_participation)
assign(
state.current_epoch_participation, stateDiff.current_epoch_participation)
state.justification_bits = stateDiff.justification_bits
assign(
state.previous_justified_checkpoint,
stateDiff.previous_justified_checkpoint)
assign(
state.current_justified_checkpoint, stateDiff.current_justified_checkpoint)
assign(state.finalized_checkpoint, stateDiff.finalized_checkpoint)
assign(state.inactivity_scores, stateDiff.inactivity_scores)
assign(state.current_sync_committee, stateDiff.current_sync_committee)
assign(state.next_sync_committee, stateDiff.next_sync_committee)
assign(
state.latest_execution_payload_header,
stateDiff.latest_execution_payload_header)
assign(state.next_withdrawal_index, stateDiff.next_withdrawal_index)
assign(
state.next_withdrawal_validator_index,
stateDiff.next_withdrawal_validator_index)
if stateDiff.historical_summary_added:
if not state.historical_summaries.add stateDiff.historical_summary:
raiseAssert "cannot readd historical summary"
# Don't update slot until the end, because various other updates depend on it
state.slot = stateDiff.slot