87 lines
3.8 KiB
Nim
87 lines
3.8 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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# Have an an aggregated aggregation ready for broadcast at
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# SECONDS_PER_SLOT * 2 / 3, i.e. 2/3 through relevant slot
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# intervals.
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#
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# The other part is arguably part of attestation pool -- the validation's
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# something that should be happing on receipt, not aggregation per se. In
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# that part, check that messages conform -- so, check for each type
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# https://github.com/ethereum/eth2.0-specs/blob/v0.10.1/specs/phase0/p2p-interface.md#topics-and-messages
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# specifies. So by the time this calls attestation pool, all validation's
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# already done.
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#
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# Finally, some of the filtering's libp2p stuff. Consistency checks between
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# topic/message types and GOSSIP_MAX_SIZE -- mostly doesn't belong here, so
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# while TODO, isn't TODO for this module.
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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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./attestation_pool, ./beacon_node_types, ./ssz
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# TODO gossipsub validation lives somewhere, maybe here
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# TODO add tests, especially for validation
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# https://github.com/status-im/nim-beacon-chain/issues/122#issuecomment-562479965
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const
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# https://github.com/ethereum/eth2.0-specs/blob/v0.10.1/specs/phase0/p2p-interface.md#configuration
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ATTESTATION_PROPAGATION_SLOT_RANGE = 32
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# https://github.com/ethereum/eth2.0-specs/blob/v0.9.4/specs/validator/0_beacon-chain-validator.md#aggregation-selection
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func get_slot_signature(state: BeaconState, slot: Slot, privkey: ValidatorPrivKey):
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ValidatorSig =
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let domain =
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get_domain(state, DOMAIN_BEACON_ATTESTER, compute_epoch_at_slot(slot))
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bls_sign(privkey, hash_tree_root(slot).data, domain)
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# https://github.com/ethereum/eth2.0-specs/blob/v0.10.1/specs/phase0/validator.md#aggregation-selection
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func is_aggregator(state: BeaconState, slot: Slot, index: uint64,
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slot_signature: ValidatorSig): bool =
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# TODO index is a CommitteeIndex, aka uint64
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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.getBytes).data[0..7]) mod modulo == 0
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proc aggregate_attestations*(
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pool: AttestationPool, state: BeaconState, index: uint64,
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privkey: ValidatorPrivKey): Option[AggregateAndProof] =
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# TODO alias CommitteeIndex to actual type then convert various uint64's here
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let
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slot = state.slot - 2
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slot_signature = get_slot_signature(state, slot, privkey)
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if slot < 0:
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return none(AggregateAndProof)
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doAssert slot + ATTESTATION_PROPAGATION_SLOT_RANGE >= state.slot
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doAssert state.slot >= slot
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# https://github.com/ethereum/eth2.0-specs/blob/v0.10.1/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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let attestation_data =
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makeAttestationData(state, slot, index, get_block_root_at_slot(state, slot))
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# https://github.com/ethereum/eth2.0-specs/blob/v0.10.1/specs/phase0/validator.md#construct-aggregate
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for attestation in getAttestationsForBlock(pool, state, slot):
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if attestation.data == attestation_data:
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# https://github.com/ethereum/eth2.0-specs/blob/v0.10.1/specs/phase0/validator.md#aggregateandproof
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return some(AggregateAndProof(
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aggregator_index: index,
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aggregate: attestation,
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selection_proof: slot_signature))
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# TODO in catch-up mode, we could get here, so probably shouldn't assert
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doAssert false
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none(AggregateAndProof)
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