65e6f892de
When using checkpoint sync, only checkpoint state is available, block is not downloaded and backfilled later. `dag.backfill` tracks latest filled `slot`, and latest `parent_root` for which no block has been synced yet. In checkpoint sync, this assumption is broken, because there, the start `dag.backfill.slot` is set based on checkpoint state slot, and the block is also not available. However, sync manager in backward mode also requests `dag.backfill.slot` and `block_clearance` then backfills the checkpoint block once it is synced. But, there is no guarantee that a peer ever sends us that block. They could send us all parent blocks and solely omit the checkpoint block itself. In that situation, we would accept the parent blocks and advance `dag.backfill`, and subsequently never request the checkpoint block again, resulting in gap inside blocks DB that is never filled. To mitigate that, the assumption is restored that `dag.backfill.slot` is the latest filled `slot`, and `dag.backfill.parent_root` is the next block that needs to be synced. By setting `slot` to `tail.slot + 1` and `parent_root` to `tail.root`, we put a fake summary into `dag.backfill` so that `block_clearance` only proceeds once checkpoint block exists. |
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| .. | ||
| vanity_logs | ||
| README.md | ||
| attestation_pool.nim | ||
| blob_quarantine.nim | ||
| block_clearance.nim | ||
| block_dag.nim | ||
| block_pools_types.nim | ||
| block_pools_types_light_client.nim | ||
| block_quarantine.nim | ||
| blockchain_dag.nim | ||
| blockchain_dag_light_client.nim | ||
| common_tools.nim | ||
| consensus_manager.nim | ||
| light_client_pool.nim | ||
| spec_cache.nim | ||
| sync_committee_msg_pool.nim | ||
| validator_change_pool.nim | ||
README.md
Consensus object pools
This folder holds the various consensus object pools needed for a blockchain client.
Object in those pools have passed the "gossip validation" filter according to specs:
- blocks: https://github.com/ethereum/consensus-specs/blob/v1.4.0-beta.5/specs/phase0/p2p-interface.md#beacon_block
- aggregate attestations: https://github.com/ethereum/consensus-specs/blob/v1.4.0-beta.5/specs/phase0/p2p-interface.md#beacon_aggregate_and_proof
- unaggregated attestation: https://github.com/ethereum/consensus-specs/blob/v1.4.0-beta.5/specs/phase0/p2p-interface.md#beacon_attestation_subnet_id
- voluntary exits: https://github.com/ethereum/consensus-specs/blob/v1.4.0-beta.5/specs/phase0/p2p-interface.md#voluntary_exit
- Attester slashings: https://github.com/ethereum/consensus-specs/blob/v1.4.0-beta.5/specs/phase0/p2p-interface.md#attester_slashing
- Proposer slashings: https://github.com/ethereum/consensus-specs/blob/v1.4.0-beta.5/specs/phase0/p2p-interface.md#proposer_slashing
After "gossip validation" the consensus objects can be rebroadcasted as they are optimistically good, however for internal processing further verification is needed. For blocks, this means verifying state transition and all contained cryptographic signatures (instead of just the proposer signature). For other consensus objects, it is possible that gossip validation is a superset of consensus verification (TODO).
The pools presenet in this folder are:
- block_pools:
- block_quarantine: for seemingly valid blocks that are on a fork unknown to us.
- block_clearance: to verify (state_transition + cryptography) candidate blocks.
- blockchain_dag: an in-memory direct-acyclic graph of fully validated and verified blockchain candidates with the tail being the last finalized epoch. A block in the DAG MUST be in the fork choice and a block in the fork choice MUST be in the DAG (except for orphans following finalization). On finalization non-empty epoch blocks are stored in the beacon_chain_db.
- attestation_pool: Handles the attestation received from gossip and collect them for fork choice.
- validator_change_pool: Handle voluntary exits and forced exits (attester slashings and proposer slashings)