03005f48e1
In the ChainDAG, 3 block pointers are kept: genesis, tail and head. This PR adds one more block pointer: the backfill block which represents the block that has been backfilled so far. When doing a checkpoint sync, a random block is given as starting point - this is the tail block, and we require that the tail block has a corresponding state. When backfilling, we end up with blocks without corresponding states, hence we cannot use `tail` as a backfill pointer - there is no state. Nonetheless, we need to keep track of where we are in the backfill process between restarts, such that we can answer GetBeaconBlocksByRange requests. This PR adds the basic support for backfill handling - it needs to be integrated with backfill sync, and the REST API needs to be adjusted to take advantage of the new backfilled blocks when responding to certain requests. Future work will also enable moving the tail in either direction: * pruning means moving the tail forward in time and removing states * backwards means recreating past states from genesis, such that intermediate states are recreated step by step all the way to the tail - at that point, tail, genesis and backfill will match up. * backfilling is done when backfill != genesis - later, this will be the WSS checkpoint instead |
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| .. | ||
| README.md | ||
| attestation_pool.nim | ||
| block_clearance.nim | ||
| block_dag.nim | ||
| block_pools_types.nim | ||
| block_quarantine.nim | ||
| blockchain_dag.nim | ||
| exit_pool.nim | ||
| spec_cache.nim | ||
| sync_committee_msg_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/v1.1.6/specs/phase0/p2p-interface.md#beacon_block
- aggregate attestations: https://github.com/ethereum/consensus-specs/blob/v1.1.6/specs/phase0/p2p-interface.md#beacon_aggregate_and_proof
- unaggregated attestation: https://github.com/ethereum/consensus-specs/blob/v1.1.6/specs/phase0/p2p-interface.md#beacon_attestation_subnet_id
- voluntary exits: https://github.com/ethereum/consensus-specs/blob/v1.1.6/specs/phase0/p2p-interface.md#voluntary_exit
- Attester slashings: https://github.com/ethereum/consensus-specs/blob/v1.1.6/specs/phase0/p2p-interface.md#attester_slashing
- Proposer slashings: https://github.com/ethereum/consensus-specs/blob/v1.1.6/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.
- exit_pool: Handle voluntary exits and forced exits (attester slashings and proposer slashings)