* Initial commit.
* NextAttestationEntry type.
* Add doppelgangerCheck and actual check.
* Recover deleted check.
* Remove NextAttestainEntry changes.
* More cleanups for NextAttestationEntry.
* Address review comments.
* Remove GENESIS_EPOCH specific check branch.
* Decrease number of full epochs for doppelganger check in VC.
Co-authored-by: zah <zahary@status.im>
We currently use `BlockError` for both beacon blocks and LC objects.
In light of EIP4844, we will likely also use it for blob sidecars.
To avoid confusion, renaming it to a more generic `VerifierError`,
and update its documentation to be more generic.
To avoid long lines as a followup, also renaming the `block_processor`'s
`BlockProcessingCompleted.completed`->`ProcessingStatus.completed` and
`BlockProcessingCompleted.notCompleted`->`ProcessingStatus.notCompleted`
In optimistic mode, Nimbus will sync optimistically even when the
execution client is offline / not available.
An optimistic node is less secure because it has not validated block
transactions via the execution client and can thus not be used for
validation duties.
* avoid database race-condition inconsistency after fcU `INVALID` then crash
* ensure head doesn't fall behind finalized; add more tests for head movement/reloading DAG
The optimistic candidate block check that only imports a new block into
the EL client if its parent block also had execution enabled is not
needed anymore, as mainnet has merged and the attack period is over.
* more efficient forkchoiceUpdated usage
* await rather than asyncSpawn; ensure head update before dag.updateHead
* use action tracker rather than attached validators to check for next slot proposal; use wall slot + 1 rather than state slot + 1 to correctly check when missing blocks
* re-add two-fcU case for when newPayload not VALID
* check dynamicFeeRecipientsStore for potential proposal
* remove duplicate checks for whether next proposer
When the BN-embedded LC makes sync progress, pass the corresponding
execution block hash to the EL via `engine_forkchoiceUpdatedV1`.
This allows the EL to sync to wall slot while the chain DAG is behind.
Renamed `--light-client` to `--sync-light-client` for clarity, and
`--light-client-trusted-block-root` to `--trusted-block-root` for
consistency with `nimbus_light_client`.
Note that this does not work well in practice at this time:
- Geth sticks to the optimistic sync:
"Ignoring payload while snap syncing" (when passing the LC head)
"Forkchoice requested unknown head" (when updating to LC head)
- Nethermind syncs to LC head but does not report ancestors as VALID,
so the main forward sync is still stuck in optimistic mode:
"Pre-pivot block, ignored and returned Syncing"
To aid EL client teams in fixing those issues, having this available
as a hidden option is still useful.
The optimistic sync spec was updated since the LC based optsync module
was introduced. It is no longer necessary to wait for the justified
checkpoint to have execution enabled; instead, any block is okay to be
optimistically imported to the EL client, as long as its parent block
has execution enabled. Complex syncing logic has been removed, and the
LC optsync module will now follow gossip directly, reducing the latency
when using this module. Note that because this is now based on gossip
instead of using sync manager / request manager, that individual blocks
may be missed. However, EL clients should recover from this by fetching
missing blocks themselves.
When the EL fails to respond to `newPayload`, e.g., because connection
to the EL got interrupted, or due to misconfiguration, optimistic blocks
cannot be imported according to spec. This condition is treated the same
as if the peer returned a block with missing parent which gets the block
out of our processing queue, but can have nasty side effects.
For example, if sync manager asks for validation of a block known to be
in the finalized range, if it receives a `MissingParent` verdict, the
peer is immediately removed from the peer pool.
```
DBG 2022-08-24 11:45:26.874+02:00 newPayload: inserting block into execution engine parentHash=e4ca7424 blockHash=36cdc198 stateRoot=cf3902c1 receiptsRoot=56e81f17 prevRandao=0b49a172 blockNumber=1518089 gasLimit=30000000 gasUsed=0 timestamp=1657980396 extraDataLen=0 baseFeePerGas=7 numTransactions=0
ERR 2022-08-24 11:45:26.875+02:00 newPayload failed msg="Transport is not initialised (missing a call to connect?)"
DBG 2022-08-24 11:45:26.875+02:00 Block pool rejected peer's response topics="syncman" request=187232:32@1475 peer=16U*MsCJdx direction=forward blocks_map=xxxxxxxxxxxxxxxxxxxxxxxxxxxx.xxx blocks_count=31 ok=false unviable=false missing_parent=true sync_ident=main
ERR 2022-08-24 11:45:26.875+02:00 Unexpected missing parent at finalized epoch slot topics="syncman" request=187232:32@1475 peer=16U*MsCJdx direction=forward rewind_to_slot=187232 blocks_count=31 blocks_map=xxxxxxxxxxxxxxxxxxxxxxxxxxxx.xxx sync_ident=main
DBG 2022-08-24 11:45:26.875+02:00 Peer was removed from PeerPool due to low score topics="beacnde" peer=16U*MsCJdx peer_score=-1000 score_low_limit=0 score_high_limit=1000
DBG 2022-08-24 11:45:26.875+02:00 Lost connection to peer topics="networking" peer=16U*MsCJdx connections=0
```
By delaying issuing a verdict until the EL connection is restored and
`newPayload` successfully ran, the problem should be fixed. This also
induces back pressure to the sync manager by stopping download of new
blocks (or re-downloading the same block over and over again).
When the client was started without any validators, the doppelganger
detection structures were never initialized properly. Later, when
validators were added through the Keymanager API, they interacted
with the uninitialized doppelganger detection structures and their
duties were inappropriately skipped.
In order to avoid full replays when validating attestations hailing from
untaken forks, it's better to keep shufflings separate from `EpochRef`
and perform a lookahead on the shuffling when processing the block that
determines them.
This also helps performance in the case where REST clients are trying to
perform lookahead on attestation duties and decreases memory usage by
sharing shufflings between EpochRef instances of the same dependent
root.
The light client sync protocol employs heuristics to ensure it does not
become stuck during non-finality or low sync committee participation.
These can enable use cases that prefer availability of recent data
over security. For our syncing use case, though, security is preferred.
An option is added to light client processor to configure this tradeoff.
tersec
Eugene Kabanov
Etan Kissling
Jacek Sieka
zah
Miran