nimbus-eth2/beacon_chain/spec/network.nim

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# beacon_chain
# Copyright (c) 2018-2020 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: [Defect].}
import
std/[strformat, sets, random],
./datatypes, ./helpers, ./validator
const
# https://github.com/ethereum/eth2.0-specs/blob/v1.0.0-rc.0/specs/phase0/p2p-interface.md#topics-and-messages
topicBeaconBlocksSuffix* = "beacon_block/ssz"
topicVoluntaryExitsSuffix* = "voluntary_exit/ssz"
topicProposerSlashingsSuffix* = "proposer_slashing/ssz"
topicAttesterSlashingsSuffix* = "attester_slashing/ssz"
topicAggregateAndProofsSuffix* = "beacon_aggregate_and_proof/ssz"
# https://github.com/ethereum/eth2.0-specs/blob/v1.0.0-rc.0/specs/phase0/validator.md#misc
ATTESTATION_SUBNET_COUNT* = 64
# https://github.com/ethereum/eth2.0-specs/blob/v1.0.0-rc.0/specs/phase0/p2p-interface.md#eth2-network-interaction-domains
MAX_CHUNK_SIZE* = 1 * 1024 * 1024 # bytes
GOSSIP_MAX_SIZE* = 1 * 1024 * 1024 # bytes
TTFB_TIMEOUT* = 5.seconds
RESP_TIMEOUT* = 10.seconds
defaultEth2TcpPort* = 9000
# This is not part of the spec yet!
defaultEth2RpcPort* = 9090
func getBeaconBlocksTopic*(forkDigest: ForkDigest): string =
try:
&"/eth2/{$forkDigest}/{topicBeaconBlocksSuffix}"
except ValueError as e:
raiseAssert e.msg
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func getVoluntaryExitsTopic*(forkDigest: ForkDigest): string =
try:
&"/eth2/{$forkDigest}/{topicVoluntaryExitsSuffix}"
except ValueError as e:
raiseAssert e.msg
func getProposerSlashingsTopic*(forkDigest: ForkDigest): string =
try:
&"/eth2/{$forkDigest}/{topicProposerSlashingsSuffix}"
except ValueError as e:
raiseAssert e.msg
func getAttesterSlashingsTopic*(forkDigest: ForkDigest): string =
try:
&"/eth2/{$forkDigest}/{topicAttesterSlashingsSuffix}"
except ValueError as e:
raiseAssert e.msg
func getAggregateAndProofsTopic*(forkDigest: ForkDigest): string =
try:
&"/eth2/{$forkDigest}/{topicAggregateAndProofsSuffix}"
except ValueError as e:
raiseAssert e.msg
# https://github.com/ethereum/eth2.0-specs/blob/v1.0.0-rc.0/specs/phase0/validator.md#broadcast-attestation
func compute_subnet_for_attestation*(
committees_per_slot: uint64, slot: Slot, committee_index: CommitteeIndex):
uint64 =
# Compute the correct subnet for an attestation for Phase 0.
# Note, this mimics expected Phase 1 behavior where attestations will be
# mapped to their shard subnet.
let
slots_since_epoch_start = slot mod SLOTS_PER_EPOCH
committees_since_epoch_start =
committees_per_slot * slots_since_epoch_start
(committees_since_epoch_start + committee_index.uint64) mod
ATTESTATION_SUBNET_COUNT
# https://github.com/ethereum/eth2.0-specs/blob/v1.0.0-rc.0/specs/phase0/validator.md#broadcast-attestation
func getAttestationTopic*(forkDigest: ForkDigest, subnetIndex: uint64):
string =
## For subscribing and unsubscribing to/from a subnet.
doAssert subnetIndex < ATTESTATION_SUBNET_COUNT
try:
&"/eth2/{$forkDigest}/beacon_attestation_{subnetIndex}/ssz"
except ValueError as e:
raiseAssert e.msg
func getAttestationTopic*(forkDigest: ForkDigest,
attestation: Attestation,
num_active_validators: uint64): string =
getAttestationTopic(
forkDigest,
compute_subnet_for_attestation(
get_committee_count_per_slot(num_active_validators),
attestation.data.slot, attestation.data.index.CommitteeIndex))
func get_committee_assignments(
state: BeaconState, epoch: Epoch,
validator_indices: HashSet[ValidatorIndex]):
seq[tuple[subnetIndex: uint64, slot: Slot]] =
var cache = StateCache()
let
committees_per_slot = get_committee_count_per_slot(state, epoch, cache)
start_slot = compute_start_slot_at_epoch(epoch)
for slot in start_slot ..< start_slot + SLOTS_PER_EPOCH:
for index in 0'u64 ..< committees_per_slot:
let idx = index.CommitteeIndex
if not disjoint(validator_indices,
get_beacon_committee(state, slot, idx, cache).toHashSet):
result.add(
(compute_subnet_for_attestation(committees_per_slot, slot, idx),
slot))
# https://github.com/ethereum/eth2.0-specs/blob/v1.0.0-rc.0/specs/phase0/validator.md#phase-0-attestation-subnet-stability
proc getStabilitySubnetLength*(): uint64 =
EPOCHS_PER_RANDOM_SUBNET_SUBSCRIPTION +
rand(EPOCHS_PER_RANDOM_SUBNET_SUBSCRIPTION.int).uint64
proc get_attestation_subnet_changes*(
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state: BeaconState, attachedValidators: openArray[ValidatorIndex],
prevAttestationSubnets: AttestationSubnets, epoch: Epoch):
tuple[a: AttestationSubnets, b: set[uint8], c: set[uint8]] =
static: doAssert ATTESTATION_SUBNET_COUNT == 64 # Fits in a set[uint8]
doAssert attachedValidators.len > 0
var attestationSubnets = prevAttestationSubnets
# https://github.com/ethereum/eth2.0-specs/blob/v1.0.0-rc.0/specs/phase0/validator.md#phase-0-attestation-subnet-stability
let prevStabilitySubnet = {attestationSubnets.stabilitySubnet.uint8}
if epoch >= attestationSubnets.stabilitySubnetExpirationEpoch:
attestationSubnets.stabilitySubnet =
rand(ATTESTATION_SUBNET_COUNT - 1).uint64
attestationSubnets.stabilitySubnetExpirationEpoch =
epoch + getStabilitySubnetLength()
var nextEpochSubnets: set[uint8]
for it in get_committee_assignments(
state, state.slot.epoch + 1, attachedValidators.toHashSet):
nextEpochSubnets.incl it.subnetIndex.uint8
doAssert nextEpochSubnets.len <= attachedValidators.len
let
epochParity = epoch mod 2
stabilitySet = {attestationSubnets.stabilitySubnet.uint8}
currentEpochSubnets = attestationSubnets.subscribedSubnets[1 - epochParity]
expiringSubnets =
(prevStabilitySubnet +
attestationSubnets.subscribedSubnets[epochParity]) -
nextEpochSubnets - currentEpochSubnets - stabilitySet
newSubnets =
(nextEpochSubnets + stabilitySet) -
(currentEpochSubnets + prevStabilitySubnet)
doAssert newSubnets.len <= attachedValidators.len + 1
attestationSubnets.subscribedSubnets[epochParity] = newSubnets
(attestationSubnets, expiringSubnets, newSubnets)