87 lines
3.9 KiB
Nim
87 lines
3.9 KiB
Nim
# beacon_chain
|
|
# Copyright (c) 2019 Status Research & Development GmbH
|
|
# Licensed and distributed under either of
|
|
# * MIT license (license terms in the root directory or at http://opensource.org/licenses/MIT).
|
|
# * Apache v2 license (license terms in the root directory or at http://www.apache.org/licenses/LICENSE-2.0).
|
|
# at your option. This file may not be copied, modified, or distributed except according to those terms.
|
|
|
|
# Have an an aggregated aggregation ready for broadcast at
|
|
# SECONDS_PER_SLOT * 2 / 3, i.e. 2/3 through relevant slot
|
|
# intervals.
|
|
#
|
|
# The other part is arguably part of attestation pool -- the validation's
|
|
# something that should be happing on receipt, not aggregation per se. In
|
|
# that part, check that messages conform -- so, check for each type
|
|
# https://github.com/ethereum/eth2.0-specs/blob/v0.9.3/specs/networking/p2p-interface.md#topics-and-messages
|
|
# specifies. So by the time this calls attestation pool, all validation's
|
|
# already done.
|
|
#
|
|
# Finally, some of the filtering's libp2p stuff. Consistency checks between
|
|
# topic/message types and GOSSIP_MAX_SIZE -- mostly doesn't belong here, so
|
|
# while TODO, isn't TODO for this module.
|
|
|
|
import
|
|
options,
|
|
./spec/[beaconstate, datatypes, crypto, digest, helpers, validator],
|
|
./attestation_pool, ./beacon_node_types, ./ssz
|
|
|
|
# TODO gossipsub validation lives somewhere, maybe here
|
|
# TODO add tests, especially for validation
|
|
# https://github.com/status-im/nim-beacon-chain/issues/122#issuecomment-562479965
|
|
|
|
const
|
|
# https://github.com/ethereum/eth2.0-specs/blob/v0.9.3/specs/networking/p2p-interface.md#configuration
|
|
ATTESTATION_PROPAGATION_SLOT_RANGE = 32
|
|
|
|
# https://github.com/ethereum/eth2.0-specs/blob/v0.9.3/specs/validator/0_beacon-chain-validator.md#aggregation-selection
|
|
func get_slot_signature(state: BeaconState, slot: Slot, privkey: ValidatorPrivKey):
|
|
ValidatorSig =
|
|
let domain =
|
|
get_domain(state, DOMAIN_BEACON_ATTESTER, compute_epoch_at_slot(slot))
|
|
bls_sign(privkey, hash_tree_root(slot).data, domain)
|
|
|
|
# https://github.com/ethereum/eth2.0-specs/blob/v0.9.3/specs/validator/0_beacon-chain-validator.md#aggregation-selection
|
|
func is_aggregator(state: BeaconState, slot: Slot, index: uint64,
|
|
slot_signature: ValidatorSig): bool =
|
|
# TODO index is a CommitteeIndex, aka uint64
|
|
var cache = get_empty_per_epoch_cache()
|
|
|
|
let
|
|
committee = get_beacon_committee(state, slot, index, cache)
|
|
modulo = max(1, len(committee) div TARGET_AGGREGATORS_PER_COMMITTEE).uint64
|
|
bytes_to_int(eth2hash(slot_signature.getBytes).data[0..7]) mod modulo == 0
|
|
|
|
proc aggregate_attestations*(
|
|
pool: AttestationPool, state: BeaconState, index: uint64,
|
|
privkey: ValidatorPrivKey): Option[AggregateAndProof] =
|
|
# TODO alias CommitteeIndex to actual type then convert various uint64's here
|
|
|
|
let
|
|
slot = state.slot - 2
|
|
slot_signature = get_slot_signature(state, slot, privkey)
|
|
|
|
if slot < 0:
|
|
return none(AggregateAndProof)
|
|
doAssert slot + ATTESTATION_PROPAGATION_SLOT_RANGE >= state.slot
|
|
doAssert state.slot >= slot
|
|
|
|
# https://github.com/ethereum/eth2.0-specs/blob/v0.9.3/specs/validator/0_beacon-chain-validator.md#aggregation-selection
|
|
if not is_aggregator(state, slot, index, slot_signature):
|
|
return none(AggregateAndProof)
|
|
|
|
let attestation_data =
|
|
makeAttestationData(state, slot, index, get_block_root_at_slot(state, slot))
|
|
|
|
# https://github.com/ethereum/eth2.0-specs/blob/v0.9.3/specs/validator/0_beacon-chain-validator.md#construct-aggregate
|
|
for attestation in getAttestationsForBlock(pool, state, slot):
|
|
if attestation.data == attestation_data:
|
|
# https://github.com/ethereum/eth2.0-specs/blob/v0.9.3/specs/validator/0_beacon-chain-validator.md#aggregateandproof
|
|
return some(AggregateAndProof(
|
|
aggregator_index: index,
|
|
aggregate: attestation,
|
|
selection_proof: slot_signature))
|
|
|
|
# TODO in catch-up mode, we could get here, so probably shouldn't assert
|
|
doAssert false
|
|
none(AggregateAndProof)
|