While syncing the finalized portion of the chain, the execution client
cannot efficiently sync and most of the time returns `SYNCING` - in this
PR, we use CL-verified optmistic sync as long as the block is claimed to
be finalized, only occasionally updating the EL with progress.
Although a peer might lie about what is finalized and what isn't,
eventually we'll call the execution client - thus, all a dishonest
client can do is delay execution verification slightly. Gossip blocks in
particular are never assumed to be finalized.
Distinguish between those code locations that need to be updated on each
light client data format change, and those others that should generally
be fine, as long as a valid light client object is processed.
The former are tagged with static assert for `LightClientDataFork.high`.
The latter are changed to `lcDataFork > LightClientDataFork.None` to
indicate that they depend only on presence of any valid object.
Also bundled a few minor cleanups and fixes.
Also add `Forky` type for `LightClientStore` and minor fixes / cleanups.
The light client data structures were changed to accommodate additional
fields in future forks (e.g., to also hold execution data).
There is a minor change to the JSON serialization, where the `header`
properties are now nested inside a `LightClientHeader`.
The SSZ serialization remains compatible.
See https://github.com/ethereum/consensus-specs/pull/3190
and https://github.com/ethereum/beacon-APIs/pull/287
In a future fork, light client data will be extended with execution info
to support more use cases. To anticipate such an upgrade, introduce
`Forky` and `Forked` types, and ready the database schema.
Because the mapping of sync committee periods to fork versions is not
necessarily unique (fork schedule not in sync with period boundaries),
an additional column is added to `period` -> `LightClientUpdate` table.
Bellatrix and Altair light client data share same body, but have other
fork digests. Validate that the peer's sent fork digest matches the one
that we expect (derived from `attested_header.slot`).
When backfilling, we only need to download blocks that are newer than
MIN_EPOCHS_FOR_BLOCK_REQUESTS - the rest cannot reliably be fetched from
the network and does not have to be provided to others.
This change affects only trusted-node-synced clients - genesis sync
continues to work as before (because it needs to construct a state by
building it from genesis).
Those wishing to complete a backfill should do so with era files
instead.
The various `PeerScore` constants are used for both beacon blocks and
LC objects, and will likely also find use for EIP4844 blob sidecars.
Renaming them to use more generically applicable names not referring
to blocks explicitly aymore.
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`
To further tighten Nimbus against spam, this PR introduces a global
quota for block requests (shared between peers) as well as a general
per-peer request limit that applies to all libp2p requests.
* apply request quota before decoding message
* for high-bandwidth requests (blocks), apply a shared global quota
which helps manage bandwidth for high-peer setups
* add metrics
* cap maximum number of chunks to download from peer (fixes#1620)
* drop support for requesting blocks via v1 / phase0 protocol
* tighten bounds checking of fixed-size messages
Implements the latest proposal for providing LC data via REST, as of
https://github.com/ethereum/beacon-APIs/pull/247 with a v0 suffix.
Requests:
- `/eth/v0/beacon/light_client/bootstrap/{block_root}`
- `/eth/v0/beacon/light_client/updates?start_period={start_period}&count={count}`
- `/eth/v0/beacon/light_client/finality_update`
- `/eth/v0/beacon/light_client/optimistic_update`
HTTP Server-Sent Events (SSE):
- `light_client_finality_update_v0`
- `light_client_optimistic_update_v0`
When the sync queue processes results for a blocks by range request,
and the requested range contained some slots that are already finalized,
`BlockError.MissingParent` currently leads to `PeerScoreBadBlocks` even
when the error occurs on a non-finalized slot in the requested range.
This patch changes the scoring in that case to `PeerScoreMissingBlocks`
for consistency with range requests solely covering non-finalized slots,
and, likewise, rewinds the sync queue to the next `rewindSlot`.
The sync protocol does not distinguish between:
- All requested slots are empty
- Peer does not have data available about requested range
Therefore, we treat EOF for `beacon_blocks_by_range` and for
`beacon_blocks_by_range` as valid responses, as if the entire epoch
really contained no single block for any slot. Once a followup response
provides new blocks, we detect that some blocks were missing and rewind.
During backfill, we also request the known-to-exist `backfill.slot`,
so we can actually detect whether an epoch really does not have blocks
or whether a response is incomplete (`PeerScoreNoBlocks`).
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.
* Use final `v1` version for light client protocols
* Unhide LC data collection options
* Default enable LC data serving
* rm unneeded import
* Connect to EL on startup
* Add docs for LC based EL sync
Adds the `--web3-url` launch argument to `nimbus_light_client` to enable
driving the EL with the optimistic head obtained from LC sync protocol.
This will keep issuing `newPayload` / `forkChoiceUpdated` requests for
new blocks, marking them as optimistic. `ZERO_HASH` is reported as the
finalized block for now.
tersec
henridf
Jacek Sieka
Etan Kissling
KonradStaniec
Eugene Kabanov
Miran