35 lines
2.1 KiB
Markdown
35 lines
2.1 KiB
Markdown
# Gossip Processing
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This folder holds a collection of modules to:
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- validate raw gossip data before
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- rebroadcasting it (potentially aggregated)
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- sending it to one of the consensus object pools
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## Validation
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Gossip validation is different from consensus verification in particular for blocks.
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- Blocks: https://github.com/ethereum/consensus-specs/blob/v1.1.10/specs/phase0/p2p-interface.md#beacon_block
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- Attestations (aggregated): https://github.com/ethereum/consensus-specs/blob/v1.1.10/specs/phase0/p2p-interface.md#beacon_aggregate_and_proof
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- Attestations (unaggregated): https://github.com/ethereum/consensus-specs/blob/v1.2.0-rc.2/specs/phase0/p2p-interface.md#attestation-subnets
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- Voluntary exits: https://github.com/ethereum/consensus-specs/blob/v1.2.0-rc.3/specs/phase0/p2p-interface.md#voluntary_exit
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- Proposer slashings: https://github.com/ethereum/consensus-specs/blob/v1.2.0-rc.3/specs/phase0/p2p-interface.md#proposer_slashing
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- Attester slashing: https://github.com/ethereum/consensus-specs/blob/v1.2.0-rc.3/specs/phase0/p2p-interface.md#attester_slashing
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There are multiple consumers of validated consensus objects:
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- a `ValidationResult.Accept` output triggers rebroadcasting in libp2p
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- We jump into method `validate(PubSub, Message)` in libp2p/protocols/pubsub/pubsub.nim
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- which was called by `rpcHandler(GossipSub, PubSubPeer, RPCMsg)`
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- a `blockValidator` message enqueues the validated object to the processing queue in `block_processor`
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- `blockQueue: AsyncQueue[BlockEntry]` (shared with request_manager and sync_manager)
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- This queue is then regularly processed to be made available to the consensus object pools.
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- a `xyzValidator` message adds the validated object to a pool in eth2_processor
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- Attestations (unaggregated and aggregated) get collected into batches.
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- Once a threshold is exceeded or after a timeout, they get validated together using BatchCrypto.
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## Security concerns
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As the first line of defense in Nimbus, modules must be able to handle bursts of data that may come:
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- from malicious nodes trying to DOS us
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- from long periods of non-finality, creating lots of forks, attestations
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