607 lines
24 KiB
Nim
607 lines
24 KiB
Nim
# Copyright (c) 2018-2024 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 https://opensource.org/licenses/MIT).
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# * Apache v2 license (license terms in the root directory or at https://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: [].}
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# Helpers and functions pertaining to managing the validator set
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import
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std/algorithm,
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"."/[crypto, helpers]
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export helpers
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const
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SEED_SIZE = sizeof(Eth2Digest)
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ROUND_SIZE = 1
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POSITION_WINDOW_SIZE = 4
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PIVOT_VIEW_SIZE = SEED_SIZE + ROUND_SIZE
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TOTAL_SIZE = PIVOT_VIEW_SIZE + POSITION_WINDOW_SIZE
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# https://github.com/ethereum/consensus-specs/blob/v1.4.0-beta.6/specs/phase0/beacon-chain.md#compute_shuffled_index
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# https://github.com/ethereum/consensus-specs/blob/v1.4.0-beta.6/specs/phase0/beacon-chain.md#compute_committee
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# Port of https://github.com/protolambda/zrnt/blob/v0.14.0/eth2/beacon/shuffle.go
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func shuffle_list*(input: var seq[ValidatorIndex], seed: Eth2Digest) =
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let list_size = input.lenu64
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if list_size <= 1: return
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var buf {.noinit.}: array[TOTAL_SIZE, byte]
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# Seed is always the first 32 bytes of the hash input, we never have to change
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# this part of the buffer.
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buf[0..<32] = seed.data
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# The original code includes a direction flag, but only the reverse direction
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# is used in eth2, so we simplify it here
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for r in 0'u8..<SHUFFLE_ROUND_COUNT.uint8:
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# spec: pivot = bytes_to_int(hash(seed + int_to_bytes1(round))[0:8]) % list_size
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# This is the "int_to_bytes1(round)", appended to the seed.
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buf[SEED_SIZE] = (SHUFFLE_ROUND_COUNT.uint8 - r - 1)
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# Seed is already in place, now just hash the correct part of the buffer,
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# and take a uint64 from it, and modulo it to get a pivot within range.
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let
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pivotDigest = eth2digest(buf.toOpenArray(0, PIVOT_VIEW_SIZE - 1))
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pivot = bytes_to_uint64(pivotDigest.data.toOpenArray(0, 7)) mod list_size
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# Split up the for-loop in two:
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# 1. Handle the part from 0 (incl) to pivot (incl). This is mirrored around
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# (pivot / 2)
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# 2. Handle the part from pivot (excl) to N (excl). This is mirrored around
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# ((pivot / 2) + (size/2))
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# The pivot defines a split in the array, with each of the splits mirroring
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# their data within the split.
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# Print out some example even/odd sized index lists, with some even/odd pivots,
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# and you can deduce how the mirroring works exactly.
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# Note that the mirror is strict enough to not consider swapping the index
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# @mirror with itself.
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# Since we are iterating through the "positions" in order, we can just
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# repeat the hash every 256th position.
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# No need to pre-compute every possible hash for efficiency like in the
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# example code.
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# We only need it consecutively (we are going through each in reverse order
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# however, but same thing)
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# spec: source = hash(seed + int_to_bytes1(round) + int_to_bytes4(position // 256))
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# - seed is still in 0:32 (excl., 32 bytes)
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# - round number is still in 32
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# - mix in the position for randomness, except the last byte of it,
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# which will be used later to select a bit from the resulting hash.
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# We start from the pivot position, and work back to the mirror position
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# (of the part left to the pivot).
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# This makes us process each pear exactly once (instead of unnecessarily
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# twice, like in the spec)
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buf[33..<37] = uint_to_bytes(uint32(pivot shr 8))
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var
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mirror = (pivot + 1) shr 1
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source = eth2digest(buf)
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byteV = source.data[(pivot and 0xff) shr 3]
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i = 0'u64
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j = pivot
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template shuffle =
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while i < mirror:
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# The pair is i,j. With j being the bigger of the two, hence the "position" identifier of the pair.
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# Every 256th bit (aligned to j).
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if (j and 0xff) == 0xff:
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# just overwrite the last part of the buffer, reuse the start (seed, round)
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buf[33..<37] = uint_to_bytes(uint32(j shr 8))
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source = eth2digest(buf)
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# Same trick with byte retrieval. Only every 8th.
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if (j and 0x07) == 0x7:
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byteV = source.data[(j and 0xff'u64) shr 3]
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let
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bitV = (byteV shr (j and 0x7)) and 0x1
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if bitV == 1:
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swap(input[i], input[j])
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i.inc
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j.dec
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shuffle
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# Now repeat, but for the part after the pivot.
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mirror = (pivot + list_size + 1) shr 1
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let lend = list_size - 1
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# Again, seed and round input is in place, just update the position.
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# We start at the end, and work back to the mirror point.
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# This makes us process each pear exactly once (instead of unnecessarily twice, like in the spec)
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buf[33..<37] = uint_to_bytes(uint32(lend shr 8))
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source = eth2digest(buf)
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byteV = source.data[(lend and 0xff) shr 3]
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i = pivot + 1'u64
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j = lend
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shuffle
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func get_shuffled_active_validator_indices*(
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state: ForkyBeaconState, epoch: Epoch,
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mix: Eth2Digest): seq[ValidatorIndex] =
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# Non-spec function, to cache a data structure from which one can cheaply
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# compute both get_active_validator_indexes() and get_beacon_committee().
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var active_validator_indices = get_active_validator_indices(state, epoch)
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let seed = get_seed(state, epoch, DOMAIN_BEACON_ATTESTER, mix)
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shuffle_list(active_validator_indices, seed)
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active_validator_indices
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func get_shuffled_active_validator_indices*(
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state: ForkyBeaconState, epoch: Epoch): seq[ValidatorIndex] =
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# Non-spec function, to cache a data structure from which one can cheaply
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# compute both get_active_validator_indexes() and get_beacon_committee().
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var active_validator_indices = get_active_validator_indices(state, epoch)
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let seed = get_seed(state, epoch, DOMAIN_BEACON_ATTESTER)
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shuffle_list(active_validator_indices, seed)
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active_validator_indices
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func get_shuffled_active_validator_indices*(
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cache: var StateCache, state: ForkyBeaconState, epoch: Epoch):
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var seq[ValidatorIndex] =
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# `cache` comes first because of nim's borrowing rules for the `var` return -
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# the `var` returns avoids copying the validator set.
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cache.shuffled_active_validator_indices.withValue(epoch, validator_indices) do:
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return validator_indices[]
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do:
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let indices = get_shuffled_active_validator_indices(state, epoch)
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return cache.shuffled_active_validator_indices.mgetOrPut(epoch, indices)
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func get_shuffled_active_validator_indices*(
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cache: var StateCache, state: ForkedHashedBeaconState, epoch: Epoch):
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seq[ValidatorIndex] =
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withState(state):
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cache.get_shuffled_active_validator_indices(forkyState.data, epoch)
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# https://github.com/ethereum/consensus-specs/blob/v1.5.0-alpha.5/specs/phase0/beacon-chain.md#get_active_validator_indices
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func count_active_validators*(state: ForkyBeaconState,
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epoch: Epoch,
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cache: var StateCache): uint64 =
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cache.get_shuffled_active_validator_indices(state, epoch).lenu64
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# https://github.com/ethereum/consensus-specs/blob/v1.4.0/specs/phase0/beacon-chain.md#get_committee_count_per_slot
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func get_committee_count_per_slot*(num_active_validators: uint64): uint64 =
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clamp(
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num_active_validators div SLOTS_PER_EPOCH div TARGET_COMMITTEE_SIZE,
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1'u64, MAX_COMMITTEES_PER_SLOT)
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func get_committee_count_per_slot*(state: ForkyBeaconState,
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epoch: Epoch,
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cache: var StateCache): uint64 =
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## Return the number of committees at ``slot``.
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let
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active_validator_count = count_active_validators(state, epoch, cache)
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get_committee_count_per_slot(active_validator_count)
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func get_committee_count_per_slot*(state: ForkedHashedBeaconState,
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epoch: Epoch,
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cache: var StateCache): uint64 =
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withState(state):
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get_committee_count_per_slot(forkyState.data, epoch, cache)
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iterator get_committee_indices*(committee_count_per_slot: uint64): CommitteeIndex =
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for idx in 0'u64..<min(committee_count_per_slot, MAX_COMMITTEES_PER_SLOT):
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let committee_index = CommitteeIndex.init(idx).expect("value clamped")
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yield committee_index
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# https://github.com/ethereum/consensus-specs/blob/v1.4.0-beta.6/specs/phase0/beacon-chain.md#compute_committee
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func compute_committee_slice*(
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active_validators, index, count: uint64): Slice[int] =
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doAssert active_validators <= ValidatorIndex.high.uint64
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if index < count:
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let
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start = (active_validators * index) div count
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endIdx = (active_validators * (index + 1)) div count
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start.int..(endIdx.int - 1)
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else:
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0 .. -1
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iterator compute_committee*(shuffled_indices: seq[ValidatorIndex],
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index: uint64, count: uint64): (int, ValidatorIndex) =
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let
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slice = compute_committee_slice(shuffled_indices.lenu64, index, count)
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var idx = 0
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for i in slice:
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yield (idx, shuffled_indices[i])
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idx += 1
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func compute_committee*(shuffled_indices: seq[ValidatorIndex],
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index: uint64, count: uint64): seq[ValidatorIndex] =
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## Return the committee corresponding to ``indices``, ``seed``, ``index``,
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## and committee ``count``.
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## In this version, we pass in the shuffled indices meaning we no longer need
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## the seed.
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let
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slice = compute_committee_slice(shuffled_indices.lenu64, index, count)
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# In spec, this calls get_shuffled_index() every time, but that's wasteful
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# Here, get_beacon_committee() gets the shuffled version.
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shuffled_indices[slice]
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func compute_committee_len*(
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active_validators, index, count: uint64): uint64 =
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## Return the committee corresponding to ``indices``, ``seed``, ``index``,
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## and committee ``count``.
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let
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slice = compute_committee_slice(active_validators, index, count)
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(slice.b - slice.a + 1).uint64
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# https://github.com/ethereum/consensus-specs/blob/v1.4.0-beta.6/specs/phase0/beacon-chain.md#get_beacon_committee
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iterator get_beacon_committee*(
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state: ForkyBeaconState, slot: Slot, index: CommitteeIndex,
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cache: var StateCache): (int, ValidatorIndex) =
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## Return the beacon committee at ``slot`` for ``index``.
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let
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epoch = epoch(slot)
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committees_per_slot = get_committee_count_per_slot(state, epoch, cache)
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for index_in_committee, idx in compute_committee(
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cache.get_shuffled_active_validator_indices(state, epoch),
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(slot mod SLOTS_PER_EPOCH) * committees_per_slot +
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index.uint64,
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committees_per_slot * SLOTS_PER_EPOCH
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): yield (index_in_committee, idx)
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func get_beacon_committee*(
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state: ForkyBeaconState, slot: Slot, index: CommitteeIndex,
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cache: var StateCache): seq[ValidatorIndex] =
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## Return the beacon committee at ``slot`` for ``index``.
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let
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epoch = epoch(slot)
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committees_per_slot = get_committee_count_per_slot(state, epoch, cache)
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compute_committee(
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cache.get_shuffled_active_validator_indices(state, epoch),
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(slot mod SLOTS_PER_EPOCH) * committees_per_slot +
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index.uint64,
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committees_per_slot * SLOTS_PER_EPOCH
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)
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func get_beacon_committee*(
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state: ForkedHashedBeaconState, slot: Slot, index: CommitteeIndex,
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cache: var StateCache): seq[ValidatorIndex] =
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# This one is used by tests/, ncli/, and a couple of places in RPC
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# TODO use the iterator version alone, to remove the risk of using
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# diverging get_beacon_committee() in tests and beacon_chain/ by a
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# wrapper approach (e.g., toSeq). This is a perf tradeoff for test
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# correctness/consistency.
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withState(state):
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get_beacon_committee(forkyState.data, slot, index, cache)
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# https://github.com/ethereum/consensus-specs/blob/v1.4.0-beta.6/specs/phase0/beacon-chain.md#get_beacon_committee
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func get_beacon_committee_len*(
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state: ForkyBeaconState, slot: Slot, index: CommitteeIndex,
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cache: var StateCache): uint64 =
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## Return the number of members in the beacon committee at ``slot``
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## for ``index``.
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let
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epoch = epoch(slot)
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committees_per_slot = get_committee_count_per_slot(state, epoch, cache)
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compute_committee_len(
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count_active_validators(state, epoch, cache),
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(slot mod SLOTS_PER_EPOCH) * committees_per_slot +
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index.uint64,
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committees_per_slot * SLOTS_PER_EPOCH
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)
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func get_beacon_committee_len*(
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state: ForkedHashedBeaconState, slot: Slot, index: CommitteeIndex,
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cache: var StateCache): uint64 =
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# This one is used by tests
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withState(state):
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get_beacon_committee_len(forkyState.data, slot, index, cache)
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# https://github.com/ethereum/consensus-specs/blob/v1.4.0-beta.6/specs/phase0/beacon-chain.md#compute_shuffled_index
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template compute_shuffled_index_aux(
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index: uint64, index_count: uint64, seed: Eth2Digest, iter: untyped):
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uint64 =
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## Return the shuffled index corresponding to ``seed`` (and ``index_count``).
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doAssert index < index_count
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var
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source_buffer {.noinit.}: array[(32+1+4), byte]
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cur_idx_permuted = index
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source_buffer[0..31] = seed.data
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# Swap or not (https://link.springer.com/content/pdf/10.1007%2F978-3-642-32009-5_1.pdf)
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# See the 'generalized domain' algorithm on page 3
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for current_round in iter:
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source_buffer[32] = current_round
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let
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# If using multiple indices, can amortize this
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pivot =
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bytes_to_uint64(eth2digest(source_buffer.toOpenArray(0, 32)).data.toOpenArray(0, 7)) mod
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index_count
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flip = ((index_count + pivot) - cur_idx_permuted) mod index_count
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position = max(cur_idx_permuted, flip)
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source_buffer[33..36] = uint_to_bytes(uint32(position shr 8))
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let
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source = eth2digest(source_buffer).data
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byte_value = source[(position mod 256) shr 3]
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bit = (byte_value shr (position mod 8)) mod 2
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cur_idx_permuted = if bit != 0: flip else: cur_idx_permuted
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cur_idx_permuted
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func compute_shuffled_index*(
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index: uint64, index_count: uint64, seed: Eth2Digest): uint64 =
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## Return the shuffled index corresponding to ``seed`` (and ``index_count``).
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compute_shuffled_index_aux(index, index_count, seed) do:
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0'u8 ..< SHUFFLE_ROUND_COUNT.uint8
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func compute_inverted_shuffled_index*(
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index: uint64, index_count: uint64, seed: Eth2Digest): uint64 =
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## Return the inverse of the shuffled index corresponding to ``seed`` (and
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## ``index_count``).
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compute_shuffled_index_aux(index, index_count, seed) do:
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countdown(SHUFFLE_ROUND_COUNT.uint8 - 1, 0'u8, 1)
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# https://github.com/ethereum/consensus-specs/blob/v1.4.0-beta.6/specs/phase0/beacon-chain.md#compute_proposer_index
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# https://github.com/ethereum/consensus-specs/blob/v1.5.0-alpha.3/specs/electra/beacon-chain.md#updated-compute_proposer_index
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template compute_proposer_index(state: ForkyBeaconState,
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indices: openArray[ValidatorIndex], seed: Eth2Digest,
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unshuffleTransform: untyped): Opt[ValidatorIndex] =
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## Return from ``indices`` a random index sampled by effective balance.
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const MAX_RANDOM_BYTE = 255
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if len(indices) == 0:
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Opt.none(ValidatorIndex)
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else:
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let seq_len {.inject.} = indices.lenu64
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var
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i = 0'u64
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buffer: array[32+8, byte]
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res: Opt[ValidatorIndex]
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buffer[0..31] = seed.data
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while true:
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buffer[32..39] = uint_to_bytes(i div 32)
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let
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shuffled_index {.inject.} =
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compute_shuffled_index(i mod seq_len, seq_len, seed)
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candidate_index = indices[unshuffleTransform]
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random_byte = (eth2digest(buffer).data)[i mod 32]
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effective_balance = state.validators[candidate_index].effective_balance
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const max_effective_balance =
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when typeof(state).kind >= ConsensusFork.Electra:
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MAX_EFFECTIVE_BALANCE_ELECTRA.Gwei # [Modified in Electra:EIP7251]
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else:
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MAX_EFFECTIVE_BALANCE.Gwei
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if effective_balance * MAX_RANDOM_BYTE >=
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max_effective_balance * random_byte:
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res = Opt.some(candidate_index)
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break
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i += 1
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doAssert res.isSome
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res
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func compute_proposer_index(state: ForkyBeaconState,
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indices: openArray[ValidatorIndex], seed: Eth2Digest):
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Opt[ValidatorIndex] =
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## Return from ``indices`` a random index sampled by effective balance.
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compute_proposer_index(state, indices, seed, shuffled_index)
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# https://github.com/ethereum/consensus-specs/blob/v1.5.0-alpha.5/specs/phase0/beacon-chain.md#get_beacon_proposer_index
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func get_beacon_proposer_index*(
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state: ForkyBeaconState, cache: var StateCache, slot: Slot):
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Opt[ValidatorIndex] =
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let epoch = get_current_epoch(state)
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if slot.epoch() != epoch:
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# compute_proposer_index depends on `effective_balance`, therefore the
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# beacon proposer index can only be computed for the "current" epoch:
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# https://github.com/ethereum/consensus-specs/pull/772#issuecomment-475574357
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return Opt.none(ValidatorIndex)
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cache.beacon_proposer_indices.withValue(slot, proposer) do:
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return proposer[]
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do:
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## Return the beacon proposer index at the current slot.
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var buffer: array[32 + 8, byte]
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buffer[0..31] = get_seed(state, epoch, DOMAIN_BEACON_PROPOSER).data
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# There's exactly one beacon proposer per slot - the same validator may
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# however propose several times in the same epoch (however unlikely)
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let indices = get_active_validator_indices(state, epoch)
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var res: Opt[ValidatorIndex]
|
|
|
|
for epoch_slot in epoch.slots():
|
|
buffer[32..39] = uint_to_bytes(epoch_slot.asUInt64)
|
|
let seed = eth2digest(buffer)
|
|
let pi = compute_proposer_index(state, indices, seed)
|
|
if epoch_slot == slot:
|
|
res = pi
|
|
cache.beacon_proposer_indices[epoch_slot] = pi
|
|
|
|
return res
|
|
|
|
# https://github.com/ethereum/consensus-specs/blob/v1.4.0-beta.6/specs/phase0/beacon-chain.md#get_beacon_proposer_index
|
|
func get_beacon_proposer_indices*(
|
|
state: ForkyBeaconState, shuffled_indices: openArray[ValidatorIndex], epoch: Epoch):
|
|
seq[Opt[ValidatorIndex]] =
|
|
## Return the beacon proposer indices at the current epoch, using shuffled
|
|
## rather than sorted active validator indices.
|
|
var
|
|
buffer {.noinit.}: array[32 + 8, byte]
|
|
res: seq[Opt[ValidatorIndex]]
|
|
|
|
buffer[0..31] = get_seed(state, epoch, DOMAIN_BEACON_PROPOSER).data
|
|
let epoch_shuffle_seed = get_seed(state, epoch, DOMAIN_BEACON_ATTESTER)
|
|
|
|
for epoch_slot in epoch.slots():
|
|
buffer[32..39] = uint_to_bytes(epoch_slot.asUInt64)
|
|
res.add (
|
|
compute_proposer_index(state, shuffled_indices, eth2digest(buffer)) do:
|
|
compute_inverted_shuffled_index(
|
|
shuffled_index, seq_len, epoch_shuffle_seed))
|
|
|
|
res
|
|
|
|
# https://github.com/ethereum/consensus-specs/blob/v1.4.0-beta.6/specs/phase0/beacon-chain.md#get_beacon_proposer_index
|
|
func get_beacon_proposer_index*(state: ForkyBeaconState, cache: var StateCache):
|
|
Opt[ValidatorIndex] =
|
|
## Return the beacon proposer index at the current slot.
|
|
get_beacon_proposer_index(state, cache, state.slot)
|
|
|
|
func get_beacon_proposer_index*(state: ForkedHashedBeaconState,
|
|
cache: var StateCache, slot: Slot):
|
|
Opt[ValidatorIndex] =
|
|
withState(state):
|
|
get_beacon_proposer_index(forkyState.data, cache, slot)
|
|
|
|
# https://github.com/ethereum/consensus-specs/blob/v1.4.0/specs/phase0/validator.md#aggregation-selection
|
|
func is_aggregator*(committee_len: uint64, slot_signature: ValidatorSig): bool =
|
|
let modulo = max(1'u64, committee_len div TARGET_AGGREGATORS_PER_COMMITTEE)
|
|
bytes_to_uint64(eth2digest(
|
|
slot_signature.toRaw()).data.toOpenArray(0, 7)) mod modulo == 0
|
|
|
|
# https://github.com/ethereum/builder-specs/blob/v0.4.0/specs/bellatrix/validator.md#liveness-failsafe
|
|
func livenessFailsafeInEffect*(
|
|
block_roots: array[Limit SLOTS_PER_HISTORICAL_ROOT, Eth2Digest],
|
|
slot: Slot): bool =
|
|
const
|
|
MAX_MISSING_CONTIGUOUS = 3
|
|
MAX_MISSING_WINDOW = 5
|
|
|
|
static: doAssert MAX_MISSING_WINDOW > MAX_MISSING_CONTIGUOUS
|
|
if slot <= MAX_MISSING_CONTIGUOUS:
|
|
# Cannot ever trigger and allows a bit of safe arithmetic. Furthermore
|
|
# there's notionally always a genesis block, which pushes the earliest
|
|
# possible failure out an additional slot.
|
|
return false
|
|
|
|
# Using this slightly convoluted construction to handle wraparound better;
|
|
# baseIndex + faultInspectionWindow can overflow array but only exactly by
|
|
# the required amount. Furthermore, go back one more slot to address using
|
|
# that it looks ahead rather than looks back and whether a block's missing
|
|
# requires seeing the previous block_root.
|
|
let
|
|
faultInspectionWindow = min(distinctBase(slot) - 1, SLOTS_PER_EPOCH)
|
|
baseIndex = (slot + SLOTS_PER_HISTORICAL_ROOT - faultInspectionWindow) mod
|
|
SLOTS_PER_HISTORICAL_ROOT
|
|
endIndex = baseIndex + faultInspectionWindow - 1
|
|
|
|
doAssert endIndex mod SLOTS_PER_HISTORICAL_ROOT ==
|
|
(slot - 1) mod SLOTS_PER_HISTORICAL_ROOT
|
|
|
|
var
|
|
totalMissing = 0
|
|
streakLen = 0
|
|
maxStreakLen = 0
|
|
|
|
for i in baseIndex .. endIndex:
|
|
# This look-forward means checking slot i for being missing uses i - 1
|
|
if block_roots[(i mod SLOTS_PER_HISTORICAL_ROOT).int] ==
|
|
block_roots[((i + 1) mod SLOTS_PER_HISTORICAL_ROOT).int]:
|
|
totalMissing += 1
|
|
if totalMissing > MAX_MISSING_WINDOW:
|
|
return true
|
|
|
|
streakLen += 1
|
|
if streakLen > maxStreakLen:
|
|
maxStreakLen = streakLen
|
|
if maxStreakLen > MAX_MISSING_CONTIGUOUS:
|
|
return true
|
|
else:
|
|
streakLen = 0
|
|
|
|
false
|
|
|
|
# https://github.com/ethereum/consensus-specs/blob/v1.4.0-beta.5/specs/phase0/p2p-interface.md#attestation-subnet-subscription
|
|
func compute_subscribed_subnet(node_id: UInt256, epoch: Epoch, index: uint64):
|
|
SubnetId =
|
|
# Ensure neither `truncate` loses information
|
|
static:
|
|
doAssert EPOCHS_PER_SUBNET_SUBSCRIPTION <= high(uint64)
|
|
doAssert sizeof(UInt256) * 8 == NODE_ID_BITS
|
|
doAssert ATTESTATION_SUBNET_PREFIX_BITS < sizeof(SubnetId) * 8
|
|
|
|
let
|
|
node_id_prefix = truncate(
|
|
node_id shr (
|
|
NODE_ID_BITS - static(ATTESTATION_SUBNET_PREFIX_BITS.int)), uint64)
|
|
node_offset = truncate(
|
|
node_id mod static(EPOCHS_PER_SUBNET_SUBSCRIPTION.u256), uint64)
|
|
permutation_seed = eth2digest(uint_to_bytes(
|
|
uint64((epoch + node_offset) div EPOCHS_PER_SUBNET_SUBSCRIPTION)))
|
|
permutated_prefix = compute_shuffled_index(
|
|
node_id_prefix,
|
|
1 shl ATTESTATION_SUBNET_PREFIX_BITS,
|
|
permutation_seed,
|
|
)
|
|
SubnetId((permutated_prefix + index) mod ATTESTATION_SUBNET_COUNT)
|
|
|
|
# https://github.com/ethereum/consensus-specs/blob/v1.4.0-beta.4/specs/phase0/p2p-interface.md#attestation-subnet-subscription
|
|
iterator compute_subscribed_subnets*(node_id: UInt256, epoch: Epoch): SubnetId =
|
|
for index in 0'u64 ..< SUBNETS_PER_NODE:
|
|
yield compute_subscribed_subnet(node_id, epoch, index)
|
|
|
|
iterator get_committee_indices*(bits: AttestationCommitteeBits): CommitteeIndex =
|
|
for index, b in bits:
|
|
if b:
|
|
yield CommitteeIndex.init(uint64(index)).valueOr:
|
|
break # Too many bits! Shouldn't happen
|
|
|
|
func get_committee_index_one*(bits: AttestationCommitteeBits): Opt[CommitteeIndex] =
|
|
var res = Opt.none(CommitteeIndex)
|
|
for committee_index in get_committee_indices(bits):
|
|
if res.isSome(): return Opt.none(CommitteeIndex)
|
|
res = Opt.some(committee_index)
|
|
res
|
|
|
|
proc compute_on_chain_aggregate*(
|
|
network_aggregates: openArray[electra.Attestation]): Opt[electra.Attestation] =
|
|
# aggregates = sorted(network_aggregates, key=lambda a: get_committee_indices(a.committee_bits)[0])
|
|
let aggregates = network_aggregates.sortedByIt(it.committee_bits.get_committee_index_one().expect("just one"))
|
|
|
|
let data = aggregates[0].data
|
|
|
|
var agg: AggregateSignature
|
|
var committee_bits: AttestationCommitteeBits
|
|
|
|
var totalLen = 0
|
|
for i, a in aggregates:
|
|
totalLen += a.aggregation_bits.len
|
|
|
|
var aggregation_bits = ElectraCommitteeValidatorsBits.init(totalLen)
|
|
var pos = 0
|
|
for i, a in aggregates:
|
|
let
|
|
committee_index = ? get_committee_index_one(a.committee_bits)
|
|
first = pos == 0
|
|
|
|
for b in a.aggregation_bits:
|
|
aggregation_bits[pos] = b
|
|
pos += 1
|
|
|
|
let sig = ? a.signature.load() # Expensive
|
|
if first:
|
|
agg = AggregateSignature.init(sig)
|
|
else:
|
|
agg.aggregate(sig)
|
|
|
|
committee_bits[int(committee_index)] = true
|
|
|
|
let signature = agg.finish()
|
|
|
|
ok electra.Attestation(
|
|
aggregation_bits: aggregation_bits,
|
|
data: data,
|
|
committee_bits: committee_bits,
|
|
signature: signature.toValidatorSig(),
|
|
)
|