72 lines
3.2 KiB
Nim
72 lines
3.2 KiB
Nim
# beacon_chain
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# Copyright (c) 2019-2020 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 http://opensource.org/licenses/MIT).
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# * Apache v2 license (license terms in the root directory or at http://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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options,
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./spec/[beaconstate, datatypes, crypto, digest, helpers, validator,
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state_transition_block],
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./attestation_pool, ./beacon_node_types, ./ssz
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# https://github.com/ethereum/eth2.0-specs/blob/v0.11.1/specs/phase0/validator.md#aggregation-selection
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func is_aggregator(state: BeaconState, slot: Slot, index: CommitteeIndex,
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slot_signature: ValidatorSig): bool =
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var cache = get_empty_per_epoch_cache()
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let
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committee = get_beacon_committee(state, slot, index, cache)
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modulo = max(1, len(committee) div TARGET_AGGREGATORS_PER_COMMITTEE).uint64
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bytes_to_int(eth2hash(slot_signature.toRaw()).data[0..7]) mod modulo == 0
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proc aggregate_attestations*(
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pool: AttestationPool, state: BeaconState, index: CommitteeIndex,
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privkey: ValidatorPrivKey, trailing_distance: uint64): Option[AggregateAndProof] =
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doAssert state.slot >= trailing_distance
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# https://github.com/ethereum/eth2.0-specs/blob/v0.11.1/specs/phase0/p2p-interface.md#configuration
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doAssert trailing_distance <= ATTESTATION_PROPAGATION_SLOT_RANGE
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let
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slot = state.slot - trailing_distance
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slot_signature = get_slot_signature(
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state.fork, state.genesis_validators_root, slot, privkey)
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doAssert slot + ATTESTATION_PROPAGATION_SLOT_RANGE >= state.slot
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doAssert state.slot >= slot
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# TODO performance issue for future, via get_active_validator_indices(...)
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doAssert index.uint64 < get_committee_count_at_slot(state, slot)
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# TODO for testing purposes, refactor this into the condition check
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# and just calculation
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# https://github.com/ethereum/eth2.0-specs/blob/v0.11.1/specs/phase0/validator.md#aggregation-selection
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if not is_aggregator(state, slot, index, slot_signature):
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return none(AggregateAndProof)
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# https://github.com/ethereum/eth2.0-specs/blob/v0.11.1/specs/phase0/validator.md#attestation-data
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# describes how to construct an attestation, which applies for makeAttestationData(...)
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# TODO this won't actually match anything
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let attestation_data = AttestationData(
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slot: slot,
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index: index.uint64,
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beacon_block_root: get_block_root_at_slot(state, slot))
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# https://github.com/ethereum/eth2.0-specs/blob/v0.11.1/specs/phase0/validator.md#construct-aggregate
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# TODO once EV goes in w/ refactoring of getAttestationsForBlock, pull out the getSlot version and use
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# it. This is incorrect.
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for attestation in getAttestationsForBlock(pool, state):
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# getAttestationsForBlock(...) already aggregates
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if attestation.data == attestation_data:
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# https://github.com/ethereum/eth2.0-specs/blob/v0.11.1/specs/phase0/validator.md#aggregateandproof
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return some(AggregateAndProof(
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aggregator_index: index.uint64,
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aggregate: attestation,
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selection_proof: slot_signature))
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none(AggregateAndProof)
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