History

Etan Kissling 613f4a9a50 accelerate EL sync with LC with `--sync-light-client` (#4041 ) 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.		2022-08-29 12:16:35 +00:00
..
README.md	update spec ref URLs (#3979 )	2022-08-17 11:33:19 +00:00
batch_validation.nim	cache shuffling separately from other EpochRef data (fixes #2677 ) (#3990 )	2022-08-18 21:07:01 +03:00
block_processor.nim	accelerate EL sync with LC with `--sync-light-client` (#4041 )	2022-08-29 12:16:35 +00:00
eth2_processor.nim	update spec ref URLs (#4005 )	2022-08-20 16:03:32 +00:00
gossip_validation.nim	remove incorrect block gossip validation condition (#4044 )	2022-08-29 13:01:32 +03:00
light_client_processor.nim	update spec ref URLs (#4005 )	2022-08-20 16:03:32 +00:00
optimistic_processor.nim	reduce LC optsync latency (#4002 )	2022-08-25 03:53:59 +00:00

README.md

Gossip Processing

This folder holds a collection of modules to:

validate raw gossip data before
- rebroadcasting it (potentially aggregated)
- sending it to one of the consensus object pools

Validation

Gossip validation is different from consensus verification in particular for blocks.

Blocks: https://github.com/ethereum/consensus-specs/blob/v1.1.10/specs/phase0/p2p-interface.md#beacon_block
Attestations (aggregated): https://github.com/ethereum/consensus-specs/blob/v1.1.10/specs/phase0/p2p-interface.md#beacon_aggregate_and_proof
Attestations (unaggregated): https://github.com/ethereum/consensus-specs/blob/v1.2.0-rc.2/specs/phase0/p2p-interface.md#attestation-subnets
Voluntary exits: https://github.com/ethereum/consensus-specs/blob/v1.2.0-rc.2/specs/phase0/p2p-interface.md#voluntary_exit
Proposer slashings: https://github.com/ethereum/consensus-specs/blob/v1.2.0-rc.2/specs/phase0/p2p-interface.md#proposer_slashing
Attester slashing: https://github.com/ethereum/consensus-specs/blob/v1.2.0-rc.2/specs/phase0/p2p-interface.md#attester_slashing

There are multiple consumers of validated consensus objects:

a ValidationResult.Accept output triggers rebroadcasting in libp2p
- We jump into method validate(PubSub, Message) in libp2p/protocols/pubsub/pubsub.nim
- which was called by rpcHandler(GossipSub, PubSubPeer, RPCMsg)
a blockValidator message enqueues the validated object to the processing queue in block_processor
- blockQueue: AsyncQueue[BlockEntry] (shared with request_manager and sync_manager)
- This queue is then regularly processed to be made available to the consensus object pools.
a xyzValidator message adds the validated object to a pool in eth2_processor
- Attestations (unaggregated and aggregated) get collected into batches.
- Once a threshold is exceeded or after a timeout, they get validated together using BatchCrypto.

Security concerns

As the first line of defense in Nimbus, modules must be able to handle bursts of data that may come:

from malicious nodes trying to DOS us
from long periods of non-finality, creating lots of forks, attestations