nimbus-eth2/beacon_chain/gossip_processing/light_client_processor.nim

274 lines
9.4 KiB
Nim

# beacon_chain
# Copyright (c) 2022 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
stew/objects,
chronos, metrics,
../spec/datatypes/altair,
../spec/light_client_sync,
../consensus_object_pools/block_pools_types,
".."/[beacon_clock],
../sszdump
export sszdump
# Light Client Processor
# ------------------------------------------------------------------------------
# The light client processor handles received light client objects
declareHistogram light_client_store_object_duration_seconds,
"storeObject() duration", buckets = [0.25, 0.5, 1, 2, 4, 8, Inf]
type
DidInitializeStoreCallback* =
proc() {.gcsafe, raises: [Defect].}
LightClientProcessor* = object
## This manages the processing of received light client objects
##
## from:
## - Gossip:
## - `LightClientFinalityUpdate`
## - `LightClientOptimisticUpdate`
## - `LightClientManager`:
## - `GetLightClientBootstrap`
## - `LightClientUpdatesByRange`
## - `GetLightClientFinalityUpdate`
## - `GetLightClientOptimisticUpdate`
##
## are then verified and added to:
## - `LightClientStore`
##
## The processor will also attempt to force-update the light client state
## if no update seems to be available on the network, that is both signed by
## a supermajority of sync committee members and also improves finality.
## This logic is triggered if there is no progress for an extended period
## of time, and there are repeated messages indicating that this is the best
## available data on the network during that time period.
# Config
# ----------------------------------------------------------------
dumpEnabled: bool
dumpDirInvalid: string
dumpDirIncoming: string
# Consumer
# ----------------------------------------------------------------
store: ref Option[LightClientStore]
getBeaconTime*: GetBeaconTimeFn
didInitializeStoreCallback: DidInitializeStoreCallback
cfg: RuntimeConfig
genesis_validators_root: Eth2Digest
trustedBlockRoot: Eth2Digest
lastProgressTick: BeaconTime # Moment when last update made progress
lastDuplicateTick: BeaconTime # Moment when last duplicate update received
numDuplicatesSinceProgress: int # Number of duplicates since last progress
const
# These constants have been chosen empirically and are not backed by spec
duplicateRateLimit = chronos.seconds(5) # Rate limit for counting duplicates
duplicateCountDelay = chronos.minutes(15) # Delay to start counting duplicates
minForceUpdateDelay = chronos.minutes(30) # Minimum delay until forced-update
minForceUpdateDuplicates = 100 # Minimum duplicates until forced-update
# Initialization
# ------------------------------------------------------------------------------
proc new*(
T: type LightClientProcessor,
dumpEnabled: bool,
dumpDirInvalid, dumpDirIncoming: string,
cfg: RuntimeConfig,
genesis_validators_root, trustedBlockRoot: Eth2Digest,
store: ref Option[LightClientStore],
getBeaconTime: GetBeaconTimeFn,
didInitializeStoreCallback: DidInitializeStoreCallback = nil
): ref LightClientProcessor =
(ref LightClientProcessor)(
dumpEnabled: dumpEnabled,
dumpDirInvalid: dumpDirInvalid,
dumpDirIncoming: dumpDirIncoming,
store: store,
getBeaconTime: getBeaconTime,
didInitializeStoreCallback: didInitializeStoreCallback,
cfg: cfg,
genesis_validators_root: genesis_validators_root,
trustedBlockRoot: trustedBlockRoot
)
# Storage
# ------------------------------------------------------------------------------
proc dumpInvalidObject(
self: LightClientProcessor,
obj: SomeLightClientObject) =
if self.dumpEnabled:
dump(self.dumpDirInvalid, obj)
proc dumpObject[T](
self: LightClientProcessor,
obj: SomeLightClientObject,
res: Result[T, BlockError]) =
if self.dumpEnabled and res.isErr:
case res.error
of BlockError.Invalid:
self.dumpInvalidObject(obj)
of BlockError.MissingParent:
dump(self.dumpDirIncoming, obj)
else:
discard
proc tryForceUpdate(
self: var LightClientProcessor,
wallTime: BeaconTime) =
## Try to force-update to the next sync committee period.
let
wallSlot = wallTime.slotOrZero()
store = self.store
if store[].isSome:
case store[].get.try_light_client_store_force_update(wallSlot)
of NoUpdate:
discard
of DidUpdateWithoutSupermajority:
warn "Light client force-updated without supermajority",
finalizedSlot = store[].get.finalized_header.slot,
optimisticSlot = store[].get.optimistic_header.slot
of DidUpdateWithoutFinality:
warn "Light client force-updated without finality proof",
finalizedSlot = store[].get.finalized_header.slot,
optimisticSlot = store[].get.optimistic_header.slot
proc storeObject*(
self: var LightClientProcessor,
src: MsgSource, wallTime: BeaconTime,
obj: SomeLightClientObject): Result[void, BlockError] =
## storeObject is the main entry point for unvalidated light client objects -
## all untrusted objects pass through here. When storing an object, we will
## update the `LightClientStore` accordingly
let
startTick = Moment.now()
wallSlot = wallTime.slotOrZero()
store = self.store
res =
when obj is altair.LightClientBootstrap:
if store[].isSome:
err(BlockError.Duplicate)
else:
let initRes = initialize_light_client_store(
self.trustedBlockRoot, obj)
if initRes.isErr:
err(initRes.error)
else:
store[] = some(initRes.get)
ok()
elif obj is SomeLightClientUpdate:
if store[].isNone:
err(BlockError.MissingParent)
else:
store[].get.process_light_client_update(
obj, wallSlot, self.cfg, self.genesis_validators_root)
self.dumpObject(obj, res)
if res.isErr:
when obj is altair.LightClientUpdate:
if store[].isSome and store[].get.best_valid_update.isSome:
# `best_valid_update` gets set when no supermajority / improved finality
# is available. In that case, we will wait for a better update that once
# again fulfills those conditions. If none is received within reasonable
# time, the light client store is force-updated to `best_valid_update`.
case res.error
of BlockError.Duplicate:
if wallTime >= self.lastDuplicateTick + duplicateRateLimit:
if self.numDuplicatesSinceProgress < minForceUpdateDuplicates:
if obj.matches(store[].get.best_valid_update.get):
self.lastDuplicateTick = wallTime
inc self.numDuplicatesSinceProgress
if self.numDuplicatesSinceProgress >= minForceUpdateDuplicates and
wallTime >= self.lastProgressTick + minForceUpdateDelay:
self.tryForceUpdate(wallTime)
self.lastProgressTick = wallTime
self.lastDuplicateTick = wallTime + duplicateCountDelay
self.numDuplicatesSinceProgress = 0
else: discard
return res
when obj is altair.LightClientBootstrap | altair.LightClientUpdate:
self.lastProgressTick = wallTime
self.lastDuplicateTick = wallTime + duplicateCountDelay
self.numDuplicatesSinceProgress = 0
let
storeObjectTick = Moment.now()
storeObjectDur = storeObjectTick - startTick
light_client_store_object_duration_seconds.observe(
storeObjectDur.toFloatSeconds())
let objSlot =
when obj is altair.LightClientBootstrap:
obj.header.slot
elif obj is SomeLightClientUpdateWithFinality:
obj.finalized_header.slot
else:
obj.attested_header.slot
debug "Light client object processed",
finalizedSlot = store[].get.finalized_header.slot,
optimisticSlot = store[].get.optimistic_header.slot,
kind = typeof(obj).name,
objectSlot = objSlot,
storeObjectDur
when obj is altair.LightClientBootstrap:
if self.didInitializeStoreCallback != nil:
self.didInitializeStoreCallback()
self.didInitializeStoreCallback = nil
res
# Enqueue
# ------------------------------------------------------------------------------
proc addObject*(
self: var LightClientProcessor,
src: MsgSource,
obj: SomeLightClientObject,
resfut: Future[Result[void, BlockError]] = nil) =
## Enqueue a Gossip-validated light client object for verification
# Backpressure:
# Only one object is validated at any time -
# Light client objects are always "fast" to process
# Producers:
# - Gossip:
# - `LightClientFinalityUpdate`
# - `LightClientOptimisticUpdate`
# - `LightClientManager`:
# - `GetLightClientBootstrap`
# - `LightClientUpdatesByRange`
# - `GetLightClientFinalityUpdate`
# - `GetLightClientOptimisticUpdate`
let
wallTime = self.getBeaconTime()
(afterGenesis, wallSlot) = wallTime.toSlot()
if not afterGenesis:
error "Processing light client object before genesis, clock turned back?"
quit 1
let res = self.storeObject(src, wallTime, obj)
if resFut != nil:
resFut.complete(res)