use crate::checkpoint::CheckPoint; use crate::errors::{BeaconChainError as Error, BlockProductionError}; use crate::eth1_chain::{Eth1Chain, Eth1ChainBackend}; use crate::events::{EventHandler, EventKind}; use crate::fork_choice::{Error as ForkChoiceError, ForkChoice}; use crate::head_tracker::HeadTracker; use crate::metrics; use crate::persisted_beacon_chain::{PersistedBeaconChain, BEACON_CHAIN_DB_KEY}; use lmd_ghost::LmdGhost; use operation_pool::DepositInsertStatus; use operation_pool::{OperationPool, PersistedOperationPool}; use parking_lot::RwLock; use slog::{debug, error, info, trace, warn, Logger}; use slot_clock::SlotClock; use ssz::Encode; use state_processing::per_block_processing::{ errors::{ AttestationValidationError, AttesterSlashingValidationError, DepositValidationError, ExitValidationError, ProposerSlashingValidationError, }, verify_attestation_for_state, VerifySignatures, }; use state_processing::{ per_block_processing, per_slot_processing, BlockProcessingError, BlockSignatureStrategy, }; use std::fs; use std::io::prelude::*; use std::sync::Arc; use std::time::{Duration, Instant}; use store::iter::{ BlockRootsIterator, ReverseBlockRootIterator, ReverseStateRootIterator, StateRootsIterator, }; use store::{Error as DBError, Migrate, Store}; use tree_hash::TreeHash; use types::*; // Text included in blocks. // Must be 32-bytes or panic. // // |-------must be this long------| pub const GRAFFITI: &str = "sigp/lighthouse-0.0.0-prerelease"; /// If true, everytime a block is processed the pre-state, post-state and block are written to SSZ /// files in the temp directory. /// /// Only useful for testing. const WRITE_BLOCK_PROCESSING_SSZ: bool = cfg!(feature = "write_ssz_files"); #[derive(Debug, PartialEq)] pub enum BlockProcessingOutcome { /// Block was valid and imported into the block graph. Processed { block_root: Hash256 }, /// The blocks parent_root is unknown. ParentUnknown { parent: Hash256 }, /// The block slot is greater than the present slot. FutureSlot { present_slot: Slot, block_slot: Slot, }, /// The block state_root does not match the generated state. StateRootMismatch { block: Hash256, local: Hash256 }, /// The block was a genesis block, these blocks cannot be re-imported. GenesisBlock, /// The slot is finalized, no need to import. WouldRevertFinalizedSlot { block_slot: Slot, finalized_slot: Slot, }, /// Block is already known, no need to re-import. BlockIsAlreadyKnown, /// The block could not be applied to the state, it is invalid. PerBlockProcessingError(BlockProcessingError), } #[derive(Debug, PartialEq)] pub enum AttestationProcessingOutcome { Processed, EmptyAggregationBitfield, UnknownHeadBlock { beacon_block_root: Hash256, }, /// The attestation is attesting to a state that is later than itself. (Viz., attesting to the /// future). AttestsToFutureState { state: Slot, attestation: Slot, }, /// The slot is finalized, no need to import. FinalizedSlot { attestation: Epoch, finalized: Epoch, }, Invalid(AttestationValidationError), } pub trait BeaconChainTypes: Send + Sync + 'static { type Store: store::Store; type StoreMigrator: store::Migrate; type SlotClock: slot_clock::SlotClock; type LmdGhost: LmdGhost; type Eth1Chain: Eth1ChainBackend; type EthSpec: types::EthSpec; type EventHandler: EventHandler; } /// Represents the "Beacon Chain" component of Ethereum 2.0. Allows import of blocks and block /// operations and chooses a canonical head. pub struct BeaconChain { pub spec: ChainSpec, /// Persistent storage for blocks, states, etc. Typically an on-disk store, such as LevelDB. pub store: Arc, /// Database migrator for running background maintenance on the store. pub store_migrator: T::StoreMigrator, /// Reports the current slot, typically based upon the system clock. pub slot_clock: T::SlotClock, /// Stores all operations (e.g., `Attestation`, `Deposit`, etc) that are candidates for /// inclusion in a block. pub op_pool: OperationPool, /// Provides information from the Ethereum 1 (PoW) chain. pub eth1_chain: Option>, /// Stores a "snapshot" of the chain at the time the head-of-the-chain block was received. pub(crate) canonical_head: RwLock>, /// The root of the genesis block. pub genesis_block_root: Hash256, /// A state-machine that is updated with information from the network and chooses a canonical /// head block. pub fork_choice: ForkChoice, /// A handler for events generated by the beacon chain. pub event_handler: T::EventHandler, /// Used to track the heads of the beacon chain. pub(crate) head_tracker: HeadTracker, /// Logging to CLI, etc. pub(crate) log: Logger, } type BeaconBlockAndState = (BeaconBlock, BeaconState); impl BeaconChain { /// Attempt to save this instance to `self.store`. pub fn persist(&self) -> Result<(), Error> { let timer = metrics::start_timer(&metrics::PERSIST_CHAIN); let canonical_head = self.head(); let finalized_checkpoint = { let beacon_block_root = canonical_head.beacon_state.finalized_checkpoint.root; let beacon_block = self .store .get::>(&beacon_block_root)? .ok_or_else(|| Error::MissingBeaconBlock(beacon_block_root))?; let beacon_state_root = beacon_block.state_root; let beacon_state = self .store .get_state(&beacon_state_root, Some(beacon_block.slot))? .ok_or_else(|| Error::MissingBeaconState(beacon_state_root))?; CheckPoint { beacon_block_root, beacon_block, beacon_state_root, beacon_state, } }; let p: PersistedBeaconChain = PersistedBeaconChain { canonical_head, finalized_checkpoint, op_pool: PersistedOperationPool::from_operation_pool(&self.op_pool), genesis_block_root: self.genesis_block_root, ssz_head_tracker: self.head_tracker.to_ssz_container(), fork_choice: self.fork_choice.as_ssz_container(), }; let key = Hash256::from_slice(&BEACON_CHAIN_DB_KEY.as_bytes()); self.store.put(&key, &p)?; metrics::stop_timer(timer); Ok(()) } /// Returns the slot _right now_ according to `self.slot_clock`. Returns `Err` if the slot is /// unavailable. /// /// The slot might be unavailable due to an error with the system clock, or if the present time /// is before genesis (i.e., a negative slot). pub fn slot(&self) -> Result { self.slot_clock.now().ok_or_else(|| Error::UnableToReadSlot) } /// Returns the epoch _right now_ according to `self.slot_clock`. Returns `Err` if the epoch is /// unavailable. /// /// The epoch might be unavailable due to an error with the system clock, or if the present time /// is before genesis (i.e., a negative epoch). pub fn epoch(&self) -> Result { self.slot() .map(|slot| slot.epoch(T::EthSpec::slots_per_epoch())) } /// Returns the beacon block body for each beacon block root in `roots`. /// /// Fails if any root in `roots` does not have a corresponding block. pub fn get_block_bodies( &self, roots: &[Hash256], ) -> Result>, Error> { let bodies: Result, _> = roots .iter() .map(|root| match self.block_at_root(*root)? { Some(block) => Ok(block.body), None => Err(Error::DBInconsistent(format!("Missing block: {}", root))), }) .collect(); Ok(bodies?) } /// Returns the beacon block header for each beacon block root in `roots`. /// /// Fails if any root in `roots` does not have a corresponding block. pub fn get_block_headers(&self, roots: &[Hash256]) -> Result, Error> { let headers: Result, _> = roots .iter() .map(|root| match self.block_at_root(*root)? { Some(block) => Ok(block.block_header()), None => Err(Error::DBInconsistent("Missing block".into())), }) .collect(); Ok(headers?) } /// Iterates across all `(block_root, slot)` pairs from the head of the chain (inclusive) to /// the earliest reachable ancestor (may or may not be genesis). /// /// ## Notes /// /// `slot` always decreases by `1`. /// - Skipped slots contain the root of the closest prior /// non-skipped slot (identical to the way they are stored in `state.block_roots`) . /// - Iterator returns `(Hash256, Slot)`. /// - As this iterator starts at the `head` of the chain (viz., the best block), the first slot /// returned may be earlier than the wall-clock slot. pub fn rev_iter_block_roots(&self) -> ReverseBlockRootIterator { let head = self.head(); let iter = BlockRootsIterator::owned(self.store.clone(), head.beacon_state); ReverseBlockRootIterator::new((head.beacon_block_root, head.beacon_block.slot), iter) } /// Traverse backwards from `block_root` to find the block roots of its ancestors. /// /// ## Notes /// /// `slot` always decreases by `1`. /// - Skipped slots contain the root of the closest prior /// non-skipped slot (identical to the way they are stored in `state.block_roots`) . /// - Iterator returns `(Hash256, Slot)`. /// - The provided `block_root` is included as the first item in the iterator. pub fn rev_iter_block_roots_from( &self, block_root: Hash256, ) -> Result, Error> { let block = self .get_block(&block_root)? .ok_or_else(|| Error::MissingBeaconBlock(block_root))?; let state = self .store .get_state(&block.state_root, Some(block.slot))? .ok_or_else(|| Error::MissingBeaconState(block.state_root))?; let iter = BlockRootsIterator::owned(self.store.clone(), state); Ok(ReverseBlockRootIterator::new( (block_root, block.slot), iter, )) } /// Traverse backwards from `block_root` to find the root of the ancestor block at `slot`. pub fn get_ancestor_block_root( &self, block_root: Hash256, slot: Slot, ) -> Result, Error> { Ok(self .rev_iter_block_roots_from(block_root)? .find(|(_, ancestor_slot)| *ancestor_slot == slot) .map(|(ancestor_block_root, _)| ancestor_block_root)) } /// Iterates across all `(state_root, slot)` pairs from the head of the chain (inclusive) to /// the earliest reachable ancestor (may or may not be genesis). /// /// ## Notes /// /// `slot` always decreases by `1`. /// - Iterator returns `(Hash256, Slot)`. /// - As this iterator starts at the `head` of the chain (viz., the best block), the first slot /// returned may be earlier than the wall-clock slot. pub fn rev_iter_state_roots(&self) -> ReverseStateRootIterator { let head = self.head(); let slot = head.beacon_state.slot; let iter = StateRootsIterator::owned(self.store.clone(), head.beacon_state); ReverseStateRootIterator::new((head.beacon_state_root, slot), iter) } /// Returns the block at the given root, if any. /// /// ## Errors /// /// May return a database error. pub fn block_at_root( &self, block_root: Hash256, ) -> Result>, Error> { Ok(self.store.get(&block_root)?) } /// Returns the block at the given slot, if any. Only returns blocks in the canonical chain. /// /// ## Errors /// /// May return a database error. pub fn block_at_slot(&self, slot: Slot) -> Result>, Error> { let root = self .rev_iter_block_roots() .find(|(_, this_slot)| *this_slot == slot) .map(|(root, _)| root); if let Some(block_root) = root { Ok(self.store.get(&block_root)?) } else { Ok(None) } } /// Returns the block at the given root, if any. /// /// ## Errors /// /// May return a database error. pub fn get_block( &self, block_root: &Hash256, ) -> Result>, Error> { Ok(self.store.get(block_root)?) } /// Returns a `Checkpoint` representing the head block and state. Contains the "best block"; /// the head of the canonical `BeaconChain`. /// /// It is important to note that the `beacon_state` returned may not match the present slot. It /// is the state as it was when the head block was received, which could be some slots prior to /// now. pub fn head(&self) -> CheckPoint { self.canonical_head.read().clone() } /// Returns the current heads of the `BeaconChain`. For the canonical head, see `Self::head`. /// /// Returns `(block_root, block_slot)`. pub fn heads(&self) -> Vec<(Hash256, Slot)> { self.head_tracker.heads() } /// Returns the `BeaconState` at the given slot. /// /// Returns `None` when the state is not found in the database or there is an error skipping /// to a future state. pub fn state_at_slot(&self, slot: Slot) -> Result, Error> { let head_state = self.head().beacon_state; if slot == head_state.slot { Ok(head_state) } else if slot > head_state.slot { if slot > head_state.slot + T::EthSpec::slots_per_epoch() { warn!( self.log, "Skipping more than an epoch"; "head_slot" => head_state.slot, "request_slot" => slot ) } let start_slot = head_state.slot; let task_start = Instant::now(); let max_task_runtime = Duration::from_millis(self.spec.milliseconds_per_slot); let head_state_slot = head_state.slot; let mut state = head_state; while state.slot < slot { // Do not allow and forward state skip that takes longer than the maximum task duration. // // This is a protection against nodes doing too much work when they're not synced // to a chain. if task_start + max_task_runtime < Instant::now() { return Err(Error::StateSkipTooLarge { start_slot, requested_slot: slot, max_task_runtime, }); } match per_slot_processing(&mut state, &self.spec) { Ok(()) => (), Err(e) => { warn!( self.log, "Unable to load state at slot"; "error" => format!("{:?}", e), "head_slot" => head_state_slot, "requested_slot" => slot ); return Err(Error::NoStateForSlot(slot)); } }; } Ok(state) } else { let state_root = self .rev_iter_state_roots() .take_while(|(_root, current_slot)| *current_slot >= slot) .find(|(_root, current_slot)| *current_slot == slot) .map(|(root, _slot)| root) .ok_or_else(|| Error::NoStateForSlot(slot))?; Ok(self .store .get_state(&state_root, Some(slot))? .ok_or_else(|| Error::NoStateForSlot(slot))?) } } /// Returns the `BeaconState` the current slot (viz., `self.slot()`). /// /// - A reference to the head state (note: this keeps a read lock on the head, try to use /// sparingly). /// - The head state, but with skipped slots (for states later than the head). /// /// Returns `None` when there is an error skipping to a future state or the slot clock cannot /// be read. pub fn wall_clock_state(&self) -> Result, Error> { self.state_at_slot(self.slot()?) } /// Returns the slot of the highest block in the canonical chain. pub fn best_slot(&self) -> Slot { self.canonical_head.read().beacon_block.slot } /// Returns the validator index (if any) for the given public key. /// /// Information is retrieved from the present `beacon_state.validators`. pub fn validator_index(&self, pubkey: &PublicKeyBytes) -> Option { for (i, validator) in self.head().beacon_state.validators.iter().enumerate() { if validator.pubkey == *pubkey { return Some(i); } } None } /// Returns the block canonical root of the current canonical chain at a given slot. /// /// Returns None if a block doesn't exist at the slot. pub fn root_at_slot(&self, target_slot: Slot) -> Option { self.rev_iter_block_roots() .find(|(_root, slot)| *slot == target_slot) .map(|(root, _slot)| root) } /// Reads the slot clock (see `self.read_slot_clock()` and returns the number of slots since /// genesis. pub fn slots_since_genesis(&self) -> Option { let now = self.slot().ok()?; let genesis_slot = self.spec.genesis_slot; if now < genesis_slot { None } else { Some(SlotHeight::from(now.as_u64() - genesis_slot.as_u64())) } } /// Returns the block proposer for a given slot. /// /// Information is read from the present `beacon_state` shuffling, only information from the /// present epoch is available. pub fn block_proposer(&self, slot: Slot) -> Result { let epoch = |slot: Slot| slot.epoch(T::EthSpec::slots_per_epoch()); let head_state = &self.head().beacon_state; let mut state = if epoch(slot) == epoch(head_state.slot) { self.head().beacon_state.clone() } else { self.state_at_slot(slot)? }; state.build_committee_cache(RelativeEpoch::Current, &self.spec)?; if epoch(state.slot) != epoch(slot) { return Err(Error::InvariantViolated(format!( "Epochs in consistent in proposer lookup: state: {}, requested: {}", epoch(state.slot), epoch(slot) ))); } state .get_beacon_proposer_index(slot, &self.spec) .map_err(Into::into) } /// Returns the attestation slot and committee index for a given validator index. /// /// Information is read from the current state, so only information from the present and prior /// epoch is available. pub fn validator_attestation_slot_and_index( &self, validator_index: usize, epoch: Epoch, ) -> Result, Error> { let as_epoch = |slot: Slot| slot.epoch(T::EthSpec::slots_per_epoch()); let head_state = &self.head().beacon_state; let mut state = if epoch == as_epoch(head_state.slot) { self.head().beacon_state.clone() } else { self.state_at_slot(epoch.start_slot(T::EthSpec::slots_per_epoch()))? }; state.build_committee_cache(RelativeEpoch::Current, &self.spec)?; if as_epoch(state.slot) != epoch { return Err(Error::InvariantViolated(format!( "Epochs in consistent in attestation duties lookup: state: {}, requested: {}", as_epoch(state.slot), epoch ))); } if let Some(attestation_duty) = state.get_attestation_duties(validator_index, RelativeEpoch::Current)? { Ok(Some((attestation_duty.slot, attestation_duty.index))) } else { Ok(None) } } /// Produce an `Attestation` that is valid for the given `slot` and `index`. /// /// Always attests to the canonical chain. pub fn produce_attestation( &self, slot: Slot, index: CommitteeIndex, ) -> Result, Error> { let state = self.state_at_slot(slot)?; let head = self.head(); let data = self.produce_attestation_data_for_block( index, head.beacon_block_root, head.beacon_block.slot, &state, )?; let committee_len = state.get_beacon_committee(slot, index)?.committee.len(); Ok(Attestation { aggregation_bits: BitList::with_capacity(committee_len)?, data, signature: AggregateSignature::new(), }) } /// Produce an `AttestationData` that is valid for the given `slot`, `index`. /// /// Always attests to the canonical chain. pub fn produce_attestation_data( &self, slot: Slot, index: CommitteeIndex, ) -> Result { let state = self.state_at_slot(slot)?; let head = self.head(); self.produce_attestation_data_for_block( index, head.beacon_block_root, head.beacon_block.slot, &state, ) } /// Produce an `AttestationData` that attests to the chain denoted by `block_root` and `state`. /// /// Permits attesting to any arbitrary chain. Generally, the `produce_attestation_data` /// function should be used as it attests to the canonical chain. pub fn produce_attestation_data_for_block( &self, index: CommitteeIndex, head_block_root: Hash256, head_block_slot: Slot, state: &BeaconState, ) -> Result { // Collect some metrics. metrics::inc_counter(&metrics::ATTESTATION_PRODUCTION_REQUESTS); let timer = metrics::start_timer(&metrics::ATTESTATION_PRODUCTION_TIMES); let slots_per_epoch = T::EthSpec::slots_per_epoch(); let current_epoch_start_slot = state.current_epoch().start_slot(slots_per_epoch); // The `target_root` is the root of the first block of the current epoch. // // The `state` does not know the root of the block for it's current slot (it only knows // about blocks from prior slots). This creates an edge-case when the state is on the first // slot of the epoch -- we're unable to obtain the `target_root` because it is not a prior // root. // // This edge case is handled in two ways: // // - If the head block is on the same slot as the state, we use it's root. // - Otherwise, assume the current slot has been skipped and use the block root from the // prior slot. // // For all other cases, we simply read the `target_root` from `state.latest_block_roots`. let target_root = if state.slot == current_epoch_start_slot { if head_block_slot == current_epoch_start_slot { head_block_root } else { *state.get_block_root(current_epoch_start_slot - 1)? } } else { *state.get_block_root(current_epoch_start_slot)? }; let target = Checkpoint { epoch: state.current_epoch(), root: target_root, }; // Collect some metrics. metrics::inc_counter(&metrics::ATTESTATION_PRODUCTION_SUCCESSES); metrics::stop_timer(timer); trace!( self.log, "Produced beacon attestation data"; "beacon_block_root" => format!("{}", head_block_root), "slot" => state.slot, "index" => index ); Ok(AttestationData { slot: state.slot, index, beacon_block_root: head_block_root, source: state.current_justified_checkpoint.clone(), target, }) } /// Accept a new, potentially invalid attestation from the network. /// /// If valid, the attestation is added to `self.op_pool` and `self.fork_choice`. /// /// Returns an `Ok(AttestationProcessingOutcome)` if the chain was able to make a determination /// about the `attestation` (whether it was invalid or not). Returns an `Err` if there was an /// error during this process and no determination was able to be made. /// /// ## Notes /// /// - Whilst the `attestation` is added to fork choice, the head is not updated. That must be /// done separately. pub fn process_attestation( &self, attestation: Attestation, ) -> Result { let outcome = self.process_attestation_internal(attestation.clone()); match &outcome { Ok(outcome) => match outcome { AttestationProcessingOutcome::Processed => { trace!( self.log, "Beacon attestation imported"; "target_epoch" => attestation.data.target.epoch, "index" => attestation.data.index, ); let _ = self .event_handler .register(EventKind::BeaconAttestationImported { attestation: Box::new(attestation), }); } other => { trace!( self.log, "Beacon attestation rejected"; "reason" => format!("{:?}", other), ); let _ = self .event_handler .register(EventKind::BeaconAttestationRejected { reason: format!("Invalid attestation: {:?}", other), attestation: Box::new(attestation), }); } }, Err(e) => { error!( self.log, "Beacon attestation processing error"; "error" => format!("{:?}", e), ); let _ = self .event_handler .register(EventKind::BeaconAttestationRejected { reason: format!("Internal error: {:?}", e), attestation: Box::new(attestation), }); } } outcome } pub fn process_attestation_internal( &self, attestation: Attestation, ) -> Result { metrics::inc_counter(&metrics::ATTESTATION_PROCESSING_REQUESTS); let timer = metrics::start_timer(&metrics::ATTESTATION_PROCESSING_TIMES); if attestation.aggregation_bits.num_set_bits() == 0 { return Ok(AttestationProcessingOutcome::EmptyAggregationBitfield); } // From the store, load the attestation's "head block". // // An honest validator would have set this block to be the head of the chain (i.e., the // result of running fork choice). let result = if let Some(attestation_head_block) = self .store .get::>(&attestation.data.beacon_block_root)? { // Attempt to process the attestation using the `self.head()` state. // // This is purely an effort to avoid loading a `BeaconState` unnecessarily from the DB. let state = &self.head().beacon_state; // If it turns out that the attestation was made using the head state, then there // is no need to load a state from the database to process the attestation. // // Note: use the epoch of the target because it indicates which epoch the // attestation was created in. You cannot use the epoch of the head block, because // the block doesn't necessarily need to be in the same epoch as the attestation // (e.g., if there are skip slots between the epoch the block was created in and // the epoch for the attestation). // // This check also ensures that the slot for `data.beacon_block_root` is not higher // than `state.root` by ensuring that the block is in the history of `state`. if state.current_epoch() == attestation.data.target.epoch && (attestation.data.beacon_block_root == self.head().beacon_block_root || state .get_block_root(attestation_head_block.slot) .map(|root| *root == attestation.data.beacon_block_root) .unwrap_or_else(|_| false)) { // The head state is able to be used to validate this attestation. No need to load // anything from the database. return self.process_attestation_for_state_and_block( attestation.clone(), state, &attestation_head_block, ); } // Use the `data.beacon_block_root` to load the state from the latest non-skipped // slot preceding the attestation's creation. // // This state is guaranteed to be in the same chain as the attestation, but it's // not guaranteed to be from the same slot or epoch as the attestation. let mut state: BeaconState = self .store .get_state( &attestation_head_block.state_root, Some(attestation_head_block.slot), )? .ok_or_else(|| Error::MissingBeaconState(attestation_head_block.state_root))?; // Ensure the state loaded from the database matches the state of the attestation // head block. // // The state needs to be advanced from the current slot through to the epoch in // which the attestation was created in. It would be an error to try and use // `state.get_attestation_data_slot(..)` because the state matching the // `data.beacon_block_root` isn't necessarily in a nearby epoch to the attestation // (e.g., if there were lots of skip slots since the head of the chain and the // epoch creation epoch). for _ in state.slot.as_u64() ..attestation .data .target .epoch .start_slot(T::EthSpec::slots_per_epoch()) .as_u64() { per_slot_processing(&mut state, &self.spec)?; } state.build_committee_cache(RelativeEpoch::Current, &self.spec)?; // Reject any attestation where the `state` loaded from `data.beacon_block_root` // has a higher slot than the attestation. // // Permitting this would allow for attesters to vote on _future_ slots. if state.slot > attestation.data.slot { Ok(AttestationProcessingOutcome::AttestsToFutureState { state: state.slot, attestation: attestation.data.slot, }) } else { self.process_attestation_for_state_and_block( attestation, &state, &attestation_head_block, ) } } else { // Drop any attestation where we have not processed `attestation.data.beacon_block_root`. // // This is likely overly restrictive, we could store the attestation for later // processing. warn!( self.log, "Dropped attestation for unknown block"; "block" => format!("{}", attestation.data.beacon_block_root) ); Ok(AttestationProcessingOutcome::UnknownHeadBlock { beacon_block_root: attestation.data.beacon_block_root, }) }; metrics::stop_timer(timer); if let Ok(AttestationProcessingOutcome::Processed) = &result { metrics::inc_counter(&metrics::ATTESTATION_PROCESSING_SUCCESSES); } result } /// Verifies the `attestation` against the `state` to which it is attesting. /// /// Updates fork choice with any new latest messages, but _does not_ find or update the head. /// /// ## Notes /// /// The given `state` must fulfil one of the following conditions: /// /// - `state` corresponds to the `block.state_root` identified by /// `attestation.data.beacon_block_root`. (Viz., `attestation` was created using `state`). /// - `state.slot` is in the same epoch as `data.target.epoch` and /// `attestation.data.beacon_block_root` is in the history of `state`. /// /// Additionally, `attestation.data.beacon_block_root` **must** be available to read in /// `self.store` _and_ be the root of the given `block`. /// /// If the given conditions are not fulfilled, the function may error or provide a false /// negative (indicating that a given `attestation` is invalid when it is was validly formed). fn process_attestation_for_state_and_block( &self, attestation: Attestation, state: &BeaconState, block: &BeaconBlock, ) -> Result { // Find the highest between: // // - The highest valid finalized epoch we've ever seen (i.e., the head). // - The finalized epoch that this attestation was created against. let finalized_epoch = std::cmp::max( self.head().beacon_state.finalized_checkpoint.epoch, state.finalized_checkpoint.epoch, ); // A helper function to allow attestation processing to be metered. let verify_attestation_for_state = |state, attestation, spec, verify_signatures| { let timer = metrics::start_timer(&metrics::ATTESTATION_PROCESSING_CORE); let result = verify_attestation_for_state(state, attestation, spec, verify_signatures); metrics::stop_timer(timer); result }; if block.slot > 0 && block.slot <= finalized_epoch.start_slot(T::EthSpec::slots_per_epoch()) { // Ignore any attestation where the slot of `data.beacon_block_root` is equal to or // prior to the finalized epoch. // // For any valid attestation if the `beacon_block_root` is prior to finalization, then // all other parameters (source, target, etc) must all be prior to finalization and // therefore no longer interesting. // // We allow the case where the block is the genesis block. Without this, all // attestations prior to the first block being produced would be invalid. Ok(AttestationProcessingOutcome::FinalizedSlot { attestation: block.slot.epoch(T::EthSpec::slots_per_epoch()), finalized: finalized_epoch, }) } else if let Err(e) = verify_attestation_for_state(state, &attestation, VerifySignatures::True, &self.spec) { warn!( self.log, "Invalid attestation"; "state_epoch" => state.current_epoch(), "error" => format!("{:?}", e), ); Ok(AttestationProcessingOutcome::Invalid(e)) } else { // If the attestation is from the current or previous epoch, supply it to the fork // choice. This is FMD GHOST. let current_epoch = self.epoch()?; if attestation.data.target.epoch == current_epoch || attestation.data.target.epoch == current_epoch - 1 { // Provide the attestation to fork choice, updating the validator latest messages but // _without_ finding and updating the head. if let Err(e) = self .fork_choice .process_attestation(&state, &attestation, block) { error!( self.log, "Add attestation to fork choice failed"; "fork_choice_integrity" => format!("{:?}", self.fork_choice.verify_integrity()), "beacon_block_root" => format!("{}", attestation.data.beacon_block_root), "error" => format!("{:?}", e) ); return Err(e.into()); } } // Provide the valid attestation to op pool, which may choose to retain the // attestation for inclusion in a future block. self.op_pool .insert_attestation(attestation, state, &self.spec)?; // Update the metrics. metrics::inc_counter(&metrics::ATTESTATION_PROCESSING_SUCCESSES); Ok(AttestationProcessingOutcome::Processed) } } /// Accept some deposit and queue it for inclusion in an appropriate block. pub fn process_deposit( &self, index: u64, deposit: Deposit, ) -> Result { self.op_pool.insert_deposit(index, deposit) } /// Accept some exit and queue it for inclusion in an appropriate block. pub fn process_voluntary_exit(&self, exit: VoluntaryExit) -> Result<(), ExitValidationError> { match self.wall_clock_state() { Ok(state) => self.op_pool.insert_voluntary_exit(exit, &state, &self.spec), Err(e) => { error!( &self.log, "Unable to process voluntary exit"; "error" => format!("{:?}", e), "reason" => "no state" ); Ok(()) } } } /// Accept some proposer slashing and queue it for inclusion in an appropriate block. pub fn process_proposer_slashing( &self, proposer_slashing: ProposerSlashing, ) -> Result<(), ProposerSlashingValidationError> { match self.wall_clock_state() { Ok(state) => { self.op_pool .insert_proposer_slashing(proposer_slashing, &state, &self.spec) } Err(e) => { error!( &self.log, "Unable to process proposer slashing"; "error" => format!("{:?}", e), "reason" => "no state" ); Ok(()) } } } /// Accept some attester slashing and queue it for inclusion in an appropriate block. pub fn process_attester_slashing( &self, attester_slashing: AttesterSlashing, ) -> Result<(), AttesterSlashingValidationError> { match self.wall_clock_state() { Ok(state) => { self.op_pool .insert_attester_slashing(attester_slashing, &state, &self.spec) } Err(e) => { error!( &self.log, "Unable to process attester slashing"; "error" => format!("{:?}", e), "reason" => "no state" ); Ok(()) } } } /// Accept some block and attempt to add it to block DAG. /// /// Will accept blocks from prior slots, however it will reject any block from a future slot. pub fn process_block( &self, block: BeaconBlock, ) -> Result { let outcome = self.process_block_internal(block.clone()); match &outcome { Ok(outcome) => match outcome { BlockProcessingOutcome::Processed { block_root } => { trace!( self.log, "Beacon block imported"; "block_root" => format!("{:?}", block_root), "block_slot" => format!("{:?}", block.slot.as_u64()), ); let _ = self.event_handler.register(EventKind::BeaconBlockImported { block_root: *block_root, block: Box::new(block), }); } other => { trace!( self.log, "Beacon block rejected"; "reason" => format!("{:?}", other), ); let _ = self.event_handler.register(EventKind::BeaconBlockRejected { reason: format!("Invalid block: {:?}", other), block: Box::new(block), }); } }, Err(e) => { error!( self.log, "Beacon block processing error"; "error" => format!("{:?}", e), ); let _ = self.event_handler.register(EventKind::BeaconBlockRejected { reason: format!("Internal error: {:?}", e), block: Box::new(block), }); } } outcome } /// Accept some block and attempt to add it to block DAG. /// /// Will accept blocks from prior slots, however it will reject any block from a future slot. fn process_block_internal( &self, block: BeaconBlock, ) -> Result { metrics::inc_counter(&metrics::BLOCK_PROCESSING_REQUESTS); let full_timer = metrics::start_timer(&metrics::BLOCK_PROCESSING_TIMES); let finalized_slot = self .head() .beacon_state .finalized_checkpoint .epoch .start_slot(T::EthSpec::slots_per_epoch()); if block.slot == 0 { return Ok(BlockProcessingOutcome::GenesisBlock); } if block.slot <= finalized_slot { return Ok(BlockProcessingOutcome::WouldRevertFinalizedSlot { block_slot: block.slot, finalized_slot, }); } let block_root_timer = metrics::start_timer(&metrics::BLOCK_PROCESSING_BLOCK_ROOT); let block_root = block.canonical_root(); metrics::stop_timer(block_root_timer); if block_root == self.genesis_block_root { return Ok(BlockProcessingOutcome::GenesisBlock); } let present_slot = self.slot()?; if block.slot > present_slot { return Ok(BlockProcessingOutcome::FutureSlot { present_slot, block_slot: block.slot, }); } if self.store.exists::>(&block_root)? { return Ok(BlockProcessingOutcome::BlockIsAlreadyKnown); } // Records the time taken to load the block and state from the database during block // processing. let db_read_timer = metrics::start_timer(&metrics::BLOCK_PROCESSING_DB_READ); // Load the blocks parent block from the database, returning invalid if that block is not // found. let parent_block: BeaconBlock = match self.store.get(&block.parent_root)? { Some(block) => block, None => { return Ok(BlockProcessingOutcome::ParentUnknown { parent: block.parent_root, }); } }; // Load the parent blocks state from the database, returning an error if it is not found. // It is an error because if we know the parent block we should also know the parent state. let parent_state_root = parent_block.state_root; let parent_state = self .store .get_state(&parent_state_root, Some(parent_block.slot))? .ok_or_else(|| { Error::DBInconsistent(format!("Missing state {:?}", parent_state_root)) })?; metrics::stop_timer(db_read_timer); write_block(&block, block_root, &self.log); let catchup_timer = metrics::start_timer(&metrics::BLOCK_PROCESSING_CATCHUP_STATE); // Keep a list of any states that were "skipped" (block-less) in between the parent state // slot and the block slot. These will need to be stored in the database. let mut intermediate_states = vec![]; // Transition the parent state to the block slot. let mut state: BeaconState = parent_state; for i in state.slot.as_u64()..block.slot.as_u64() { if i > 0 { intermediate_states.push(state.clone()); } per_slot_processing(&mut state, &self.spec)?; } metrics::stop_timer(catchup_timer); let committee_timer = metrics::start_timer(&metrics::BLOCK_PROCESSING_COMMITTEE); state.build_committee_cache(RelativeEpoch::Previous, &self.spec)?; state.build_committee_cache(RelativeEpoch::Current, &self.spec)?; metrics::stop_timer(committee_timer); write_state( &format!("state_pre_block_{}", block_root), &state, &self.log, ); let core_timer = metrics::start_timer(&metrics::BLOCK_PROCESSING_CORE); // Apply the received block to its parent state (which has been transitioned into this // slot). match per_block_processing( &mut state, &block, Some(block_root), BlockSignatureStrategy::VerifyIndividual, &self.spec, ) { Err(BlockProcessingError::BeaconStateError(e)) => { return Err(Error::BeaconStateError(e)) } Err(e) => return Ok(BlockProcessingOutcome::PerBlockProcessingError(e)), _ => {} } metrics::stop_timer(core_timer); let state_root_timer = metrics::start_timer(&metrics::BLOCK_PROCESSING_STATE_ROOT); let state_root = state.canonical_root(); write_state( &format!("state_post_block_{}", block_root), &state, &self.log, ); if block.state_root != state_root { return Ok(BlockProcessingOutcome::StateRootMismatch { block: block.state_root, local: state_root, }); } metrics::stop_timer(state_root_timer); let db_write_timer = metrics::start_timer(&metrics::BLOCK_PROCESSING_DB_WRITE); // Store all the states between the parent block state and this blocks slot before storing // the final state. for (i, intermediate_state) in intermediate_states.iter().enumerate() { // To avoid doing an unnecessary tree hash, use the following (slot + 1) state's // state_roots field to find the root. let following_state = match intermediate_states.get(i + 1) { Some(following_state) => following_state, None => &state, }; let intermediate_state_root = following_state.get_state_root(intermediate_state.slot)?; self.store .put_state(&intermediate_state_root, intermediate_state)?; } // Store the block and state. self.store.put(&block_root, &block)?; self.store.put_state(&state_root, &state)?; metrics::stop_timer(db_write_timer); self.head_tracker.register_block(block_root, &block); let fork_choice_register_timer = metrics::start_timer(&metrics::BLOCK_PROCESSING_FORK_CHOICE_REGISTER); // Register the new block with the fork choice service. if let Err(e) = self .fork_choice .process_block(self, &state, &block, block_root) { error!( self.log, "Add block to fork choice failed"; "fork_choice_integrity" => format!("{:?}", self.fork_choice.verify_integrity()), "block_root" => format!("{}", block_root), "error" => format!("{:?}", e), ) } metrics::stop_timer(fork_choice_register_timer); let find_head_timer = metrics::start_timer(&metrics::BLOCK_PROCESSING_FORK_CHOICE_FIND_HEAD); // Execute the fork choice algorithm, enthroning a new head if discovered. // // Note: in the future we may choose to run fork-choice less often, potentially based upon // some heuristic around number of attestations seen for the block. if let Err(e) = self.fork_choice() { error!( self.log, "fork choice failed to find head"; "error" => format!("{:?}", e) ) }; metrics::stop_timer(find_head_timer); metrics::inc_counter(&metrics::BLOCK_PROCESSING_SUCCESSES); metrics::observe( &metrics::OPERATIONS_PER_BLOCK_ATTESTATION, block.body.attestations.len() as f64, ); metrics::stop_timer(full_timer); Ok(BlockProcessingOutcome::Processed { block_root }) } /// Produce a new block at the given `slot`. /// /// The produced block will not be inherently valid, it must be signed by a block producer. /// Block signing is out of the scope of this function and should be done by a separate program. pub fn produce_block( &self, randao_reveal: Signature, slot: Slot, ) -> Result, BlockProductionError> { let state = self .state_at_slot(slot - 1) .map_err(|_| BlockProductionError::UnableToProduceAtSlot(slot))?; self.produce_block_on_state(state, slot, randao_reveal) } /// Produce a block for some `slot` upon the given `state`. /// /// Typically the `self.produce_block()` function should be used, instead of calling this /// function directly. This function is useful for purposefully creating forks or blocks at /// non-current slots. /// /// The given state will be advanced to the given `produce_at_slot`, then a block will be /// produced at that slot height. pub fn produce_block_on_state( &self, mut state: BeaconState, produce_at_slot: Slot, randao_reveal: Signature, ) -> Result, BlockProductionError> { metrics::inc_counter(&metrics::BLOCK_PRODUCTION_REQUESTS); let timer = metrics::start_timer(&metrics::BLOCK_PRODUCTION_TIMES); let eth1_chain = self .eth1_chain .as_ref() .ok_or_else(|| BlockProductionError::NoEth1ChainConnection)?; // If required, transition the new state to the present slot. while state.slot < produce_at_slot { per_slot_processing(&mut state, &self.spec)?; } state.build_committee_cache(RelativeEpoch::Current, &self.spec)?; let parent_root = if state.slot > 0 { *state .get_block_root(state.slot - 1) .map_err(|_| BlockProductionError::UnableToGetBlockRootFromState)? } else { state.latest_block_header.canonical_root() }; let mut graffiti: [u8; 32] = [0; 32]; graffiti.copy_from_slice(GRAFFITI.as_bytes()); let (proposer_slashings, attester_slashings) = self.op_pool.get_slashings(&state, &self.spec); let eth1_data = eth1_chain.eth1_data_for_block_production(&state, &self.spec)?; let deposits = eth1_chain .deposits_for_block_inclusion(&state, ð1_data, &self.spec)? .into(); let mut block = BeaconBlock { slot: state.slot, parent_root, state_root: Hash256::zero(), // The block is not signed here, that is the task of a validator client. signature: Signature::empty_signature(), body: BeaconBlockBody { randao_reveal, eth1_data, graffiti, proposer_slashings: proposer_slashings.into(), attester_slashings: attester_slashings.into(), attestations: self.op_pool.get_attestations(&state, &self.spec).into(), deposits, voluntary_exits: self.op_pool.get_voluntary_exits(&state, &self.spec).into(), }, }; per_block_processing( &mut state, &block, None, BlockSignatureStrategy::NoVerification, &self.spec, )?; let state_root = state.canonical_root(); block.state_root = state_root; metrics::inc_counter(&metrics::BLOCK_PRODUCTION_SUCCESSES); metrics::stop_timer(timer); trace!( self.log, "Produced beacon block"; "parent" => format!("{}", block.parent_root), "attestations" => block.body.attestations.len(), "slot" => block.slot ); Ok((block, state)) } /// Execute the fork choice algorithm and enthrone the result as the canonical head. pub fn fork_choice(&self) -> Result<(), Error> { metrics::inc_counter(&metrics::FORK_CHOICE_REQUESTS); // Start fork choice metrics timer. let timer = metrics::start_timer(&metrics::FORK_CHOICE_TIMES); // Determine the root of the block that is the head of the chain. let beacon_block_root = self.fork_choice.find_head(&self)?; // If a new head was chosen. let result = if beacon_block_root != self.head().beacon_block_root { metrics::inc_counter(&metrics::FORK_CHOICE_CHANGED_HEAD); let beacon_block: BeaconBlock = self .store .get(&beacon_block_root)? .ok_or_else(|| Error::MissingBeaconBlock(beacon_block_root))?; let beacon_state_root = beacon_block.state_root; let beacon_state: BeaconState = self .store .get_state(&beacon_state_root, Some(beacon_block.slot))? .ok_or_else(|| Error::MissingBeaconState(beacon_state_root))?; let previous_slot = self.head().beacon_block.slot; let new_slot = beacon_block.slot; let is_reorg = self.head().beacon_block_root != beacon_block.parent_root; // If we switched to a new chain (instead of building atop the present chain). if is_reorg { metrics::inc_counter(&metrics::FORK_CHOICE_REORG_COUNT); warn!( self.log, "Beacon chain re-org"; "previous_head" => format!("{}", self.head().beacon_block_root), "previous_slot" => previous_slot, "new_head_parent" => format!("{}", beacon_block.parent_root), "new_head" => format!("{}", beacon_block_root), "new_slot" => new_slot ); } else { info!( self.log, "New head beacon block"; "root" => format!("{}", beacon_block_root), "slot" => new_slot, ); debug!( self.log, "Head beacon block"; "justified_root" => format!("{}", beacon_state.current_justified_checkpoint.root), "justified_epoch" => beacon_state.current_justified_checkpoint.epoch, "finalized_root" => format!("{}", beacon_state.finalized_checkpoint.root), "finalized_epoch" => beacon_state.finalized_checkpoint.epoch, ); }; let old_finalized_epoch = self.head().beacon_state.finalized_checkpoint.epoch; let new_finalized_epoch = beacon_state.finalized_checkpoint.epoch; let finalized_root = beacon_state.finalized_checkpoint.root; // Never revert back past a finalized epoch. if new_finalized_epoch < old_finalized_epoch { Err(Error::RevertedFinalizedEpoch { previous_epoch: old_finalized_epoch, new_epoch: new_finalized_epoch, }) } else { let previous_head_beacon_block_root = self.canonical_head.read().beacon_block_root; let current_head_beacon_block_root = beacon_block_root; let mut new_head = CheckPoint { beacon_block, beacon_block_root, beacon_state, beacon_state_root, }; new_head.beacon_state.build_all_caches(&self.spec)?; let timer = metrics::start_timer(&metrics::UPDATE_HEAD_TIMES); // Update the checkpoint that stores the head of the chain at the time it received the // block. *self.canonical_head.write() = new_head; metrics::stop_timer(timer); // Save `self` to `self.store`. self.persist()?; let _ = self.event_handler.register(EventKind::BeaconHeadChanged { reorg: is_reorg, previous_head_beacon_block_root, current_head_beacon_block_root, }); if new_finalized_epoch != old_finalized_epoch { self.after_finalization(old_finalized_epoch, finalized_root)?; } Ok(()) } } else { Ok(()) }; // End fork choice metrics timer. metrics::stop_timer(timer); if result.is_err() { metrics::inc_counter(&metrics::FORK_CHOICE_ERRORS); } result } /// Called after `self` has had a new block finalized. /// /// Performs pruning and finality-based optimizations. fn after_finalization( &self, old_finalized_epoch: Epoch, finalized_block_root: Hash256, ) -> Result<(), Error> { let finalized_block = self .store .get::>(&finalized_block_root)? .ok_or_else(|| Error::MissingBeaconBlock(finalized_block_root))?; let new_finalized_epoch = finalized_block.slot.epoch(T::EthSpec::slots_per_epoch()); if new_finalized_epoch < old_finalized_epoch { Err(Error::RevertedFinalizedEpoch { previous_epoch: old_finalized_epoch, new_epoch: new_finalized_epoch, }) } else { self.fork_choice .process_finalization(&finalized_block, finalized_block_root)?; let finalized_state = self .store .get_state(&finalized_block.state_root, Some(finalized_block.slot))? .ok_or_else(|| Error::MissingBeaconState(finalized_block.state_root))?; self.op_pool.prune_all(&finalized_state, &self.spec); // TODO: configurable max finality distance let max_finality_distance = 0; self.store_migrator.freeze_to_state( finalized_block.state_root, finalized_state, max_finality_distance, ); let _ = self.event_handler.register(EventKind::BeaconFinalization { epoch: new_finalized_epoch, root: finalized_block_root, }); Ok(()) } } /// Returns `true` if the given block root has not been processed. pub fn is_new_block_root(&self, beacon_block_root: &Hash256) -> Result { Ok(!self .store .exists::>(beacon_block_root)?) } /// Dumps the entire canonical chain, from the head to genesis to a vector for analysis. /// /// This could be a very expensive operation and should only be done in testing/analysis /// activities. pub fn chain_dump(&self) -> Result>, Error> { let mut dump = vec![]; let mut last_slot = CheckPoint { beacon_block: self.head().beacon_block.clone(), beacon_block_root: self.head().beacon_block_root, beacon_state: self.head().beacon_state.clone(), beacon_state_root: self.head().beacon_state_root, }; dump.push(last_slot.clone()); loop { let beacon_block_root = last_slot.beacon_block.parent_root; if beacon_block_root == Hash256::zero() { break; // Genesis has been reached. } let beacon_block: BeaconBlock = self.store.get(&beacon_block_root)?.ok_or_else(|| { Error::DBInconsistent(format!("Missing block {}", beacon_block_root)) })?; let beacon_state_root = beacon_block.state_root; let beacon_state = self .store .get_state(&beacon_state_root, Some(beacon_block.slot))? .ok_or_else(|| { Error::DBInconsistent(format!("Missing state {:?}", beacon_state_root)) })?; let slot = CheckPoint { beacon_block, beacon_block_root, beacon_state, beacon_state_root, }; dump.push(slot.clone()); last_slot = slot; } dump.reverse(); Ok(dump) } } impl Drop for BeaconChain { fn drop(&mut self) { if let Err(e) = self.persist() { error!( self.log, "Failed to persist BeaconChain on drop"; "error" => format!("{:?}", e) ) } else { info!( self.log, "Saved beacon chain state"; ) } } } fn write_state(prefix: &str, state: &BeaconState, log: &Logger) { if WRITE_BLOCK_PROCESSING_SSZ { let root = Hash256::from_slice(&state.tree_hash_root()); let filename = format!("{}_slot_{}_root_{}.ssz", prefix, state.slot, root); let mut path = std::env::temp_dir().join("lighthouse"); let _ = fs::create_dir_all(path.clone()); path = path.join(filename); match fs::File::create(path.clone()) { Ok(mut file) => { let _ = file.write_all(&state.as_ssz_bytes()); } Err(e) => error!( log, "Failed to log state"; "path" => format!("{:?}", path), "error" => format!("{:?}", e) ), } } } fn write_block(block: &BeaconBlock, root: Hash256, log: &Logger) { if WRITE_BLOCK_PROCESSING_SSZ { let filename = format!("block_slot_{}_root{}.ssz", block.slot, root); let mut path = std::env::temp_dir().join("lighthouse"); let _ = fs::create_dir_all(path.clone()); path = path.join(filename); match fs::File::create(path.clone()) { Ok(mut file) => { let _ = file.write_all(&block.as_ssz_bytes()); } Err(e) => error!( log, "Failed to log block"; "path" => format!("{:?}", path), "error" => format!("{:?}", e) ), } } } impl From for Error { fn from(e: DBError) -> Error { Error::DBError(e) } } impl From for Error { fn from(e: ForkChoiceError) -> Error { Error::ForkChoiceError(e) } } impl From for Error { fn from(e: BeaconStateError) -> Error { Error::BeaconStateError(e) } }