lighthouse/beacon_node/beacon_chain/src/block_verification.rs

982 lines
35 KiB
Rust

//! Provides `SignedBeaconBlock` verification logic.
//!
//! Specifically, it provides the following:
//!
//! - Verification for gossip blocks (i.e., should we gossip some block from the network).
//! - Verification for normal blocks (e.g., some block received on the RPC during a parent lookup).
//! - Verification for chain segments (e.g., some chain of blocks received on the RPC during a
//! sync).
//!
//! The primary source of complexity here is that we wish to avoid doing duplicate work as a block
//! moves through the verification process. For example, if some block is verified for gossip, we
//! do not wish to re-verify the block proposal signature or re-hash the block. Or, if we've
//! verified the signatures of a block during a chain segment import, we do not wish to verify each
//! signature individually again.
//!
//! The incremental processing steps (e.g., signatures verified but not the state transition) is
//! represented as a sequence of wrapper-types around the block. There is a linear progression of
//! types, starting at a `SignedBeaconBlock` and finishing with a `Fully VerifiedBlock` (see
//! diagram below).
//!
//! ```ignore
//! START
//! |
//! ▼
//! SignedBeaconBlock
//! |---------------
//! | |
//! | ▼
//! | GossipVerifiedBlock
//! | |
//! |---------------
//! |
//! ▼
//! SignatureVerifiedBlock
//! |
//! ▼
//! FullyVerifiedBlock
//! |
//! ▼
//! END
//!
//! ```
use crate::validator_pubkey_cache::ValidatorPubkeyCache;
use crate::{
beacon_chain::{
BLOCK_PROCESSING_CACHE_LOCK_TIMEOUT, MAXIMUM_GOSSIP_CLOCK_DISPARITY,
VALIDATOR_PUBKEY_CACHE_LOCK_TIMEOUT,
},
metrics, BeaconChain, BeaconChainError, BeaconChainTypes, BeaconSnapshot,
};
use parking_lot::RwLockReadGuard;
use slog::{error, Logger};
use slot_clock::SlotClock;
use ssz::Encode;
use state_processing::{
block_signature_verifier::{BlockSignatureVerifier, Error as BlockSignatureVerifierError},
per_block_processing,
per_epoch_processing::EpochProcessingSummary,
per_slot_processing, BlockProcessingError, BlockSignatureStrategy, SlotProcessingError,
};
use std::borrow::Cow;
use std::convert::TryFrom;
use std::fs;
use std::io::Write;
use store::{Error as DBError, StateBatch};
use tree_hash::TreeHash;
use types::{
BeaconBlock, BeaconState, BeaconStateError, ChainSpec, CloneConfig, EthSpec, Hash256,
PublicKey, RelativeEpoch, SignedBeaconBlock, Slot,
};
mod block_processing_outcome;
pub use block_processing_outcome::BlockProcessingOutcome;
/// Maximum block slot number. Block with slots bigger than this constant will NOT be processed.
const MAXIMUM_BLOCK_SLOT_NUMBER: u64 = 4_294_967_296; // 2^32
/// 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");
/// Returned when a block was not verified. A block is not verified for two reasons:
///
/// - The block is malformed/invalid (indicated by all results other than `BeaconChainError`.
/// - We encountered an error whilst trying to verify the block (a `BeaconChainError`).
#[derive(Debug)]
pub enum BlockError {
/// The parent block was unknown.
ParentUnknown(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,
/// A block for this proposer and slot has already been observed.
RepeatProposal { proposer: u64, slot: Slot },
/// The block slot exceeds the MAXIMUM_BLOCK_SLOT_NUMBER.
BlockSlotLimitReached,
/// The `BeaconBlock` has a `proposer_index` that does not match the index we computed locally.
///
/// The block is invalid.
IncorrectBlockProposer { block: u64, local_shuffling: u64 },
/// The proposal signature in invalid.
ProposalSignatureInvalid,
/// The `block.proposal_index` is not known.
UnknownValidator(u64),
/// A signature in the block is invalid (exactly which is unknown).
InvalidSignature,
/// The provided block is from an earlier slot than its parent.
BlockIsNotLaterThanParent { block_slot: Slot, state_slot: Slot },
/// At least one block in the chain segment did not have it's parent root set to the root of
/// the prior block.
NonLinearParentRoots,
/// The slots of the blocks in the chain segment were not strictly increasing. I.e., a child
/// had lower slot than a parent.
NonLinearSlots,
/// The block failed the specification's `per_block_processing` function, it is invalid.
PerBlockProcessingError(BlockProcessingError),
/// There was an error whilst processing the block. It is not necessarily invalid.
BeaconChainError(BeaconChainError),
}
impl From<BlockSignatureVerifierError> for BlockError {
fn from(e: BlockSignatureVerifierError) -> Self {
match e {
// Make a special distinction for `IncorrectBlockProposer` since it indicates an
// invalid block, not an internal error.
BlockSignatureVerifierError::IncorrectBlockProposer {
block,
local_shuffling,
} => BlockError::IncorrectBlockProposer {
block,
local_shuffling,
},
e => BlockError::BeaconChainError(BeaconChainError::BlockSignatureVerifierError(e)),
}
}
}
impl From<BeaconChainError> for BlockError {
fn from(e: BeaconChainError) -> Self {
BlockError::BeaconChainError(e)
}
}
impl From<BeaconStateError> for BlockError {
fn from(e: BeaconStateError) -> Self {
BlockError::BeaconChainError(BeaconChainError::BeaconStateError(e))
}
}
impl From<SlotProcessingError> for BlockError {
fn from(e: SlotProcessingError) -> Self {
BlockError::BeaconChainError(BeaconChainError::SlotProcessingError(e))
}
}
impl From<DBError> for BlockError {
fn from(e: DBError) -> Self {
BlockError::BeaconChainError(BeaconChainError::DBError(e))
}
}
/// Verify all signatures (except deposit signatures) on all blocks in the `chain_segment`. If all
/// signatures are valid, the `chain_segment` is mapped to a `Vec<SignatureVerifiedBlock>` that can
/// later be transformed into a `FullyVerifiedBlock` without re-checking the signatures. If any
/// signature in the block is invalid, an `Err` is returned (it is not possible to known _which_
/// signature was invalid).
///
/// ## Errors
///
/// The given `chain_segment` must span no more than two epochs, otherwise an error will be
/// returned.
pub fn signature_verify_chain_segment<T: BeaconChainTypes>(
chain_segment: Vec<(Hash256, SignedBeaconBlock<T::EthSpec>)>,
chain: &BeaconChain<T>,
) -> Result<Vec<SignatureVerifiedBlock<T>>, BlockError> {
let (mut parent, slot) = if let Some(block) = chain_segment.first().map(|(_, block)| block) {
let parent = load_parent(&block.message, chain)?;
(parent, block.slot())
} else {
return Ok(vec![]);
};
let highest_slot = chain_segment
.last()
.map(|(_, block)| block.slot())
.unwrap_or_else(|| slot);
let state = cheap_state_advance_to_obtain_committees(
&mut parent.beacon_state,
highest_slot,
&chain.spec,
)?;
let pubkey_cache = get_validator_pubkey_cache(chain)?;
let mut signature_verifier = get_signature_verifier(&state, &pubkey_cache, &chain.spec);
for (block_root, block) in &chain_segment {
signature_verifier.include_all_signatures(block, Some(*block_root))?;
}
if signature_verifier.verify().is_err() {
return Err(BlockError::InvalidSignature);
}
drop(pubkey_cache);
let mut signature_verified_blocks = chain_segment
.into_iter()
.map(|(block_root, block)| SignatureVerifiedBlock {
block,
block_root,
parent: None,
})
.collect::<Vec<_>>();
if let Some(signature_verified_block) = signature_verified_blocks.first_mut() {
signature_verified_block.parent = Some(parent);
}
Ok(signature_verified_blocks)
}
/// A wrapper around a `SignedBeaconBlock` that indicates it has been approved for re-gossiping on
/// the p2p network.
pub struct GossipVerifiedBlock<T: BeaconChainTypes> {
pub block: SignedBeaconBlock<T::EthSpec>,
pub block_root: Hash256,
parent: BeaconSnapshot<T::EthSpec>,
}
/// A wrapper around a `SignedBeaconBlock` that indicates that all signatures (except the deposit
/// signatures) have been verified.
pub struct SignatureVerifiedBlock<T: BeaconChainTypes> {
block: SignedBeaconBlock<T::EthSpec>,
block_root: Hash256,
parent: Option<BeaconSnapshot<T::EthSpec>>,
}
/// A wrapper around a `SignedBeaconBlock` that indicates that this block is fully verified and
/// ready to import into the `BeaconChain`. The validation includes:
///
/// - Parent is known
/// - Signatures
/// - State root check
/// - Per block processing
///
/// Note: a `FullyVerifiedBlock` is not _forever_ valid to be imported, it may later become invalid
/// due to finality or some other event. A `FullyVerifiedBlock` should be imported into the
/// `BeaconChain` immediately after it is instantiated.
pub struct FullyVerifiedBlock<T: BeaconChainTypes> {
pub block: SignedBeaconBlock<T::EthSpec>,
pub block_root: Hash256,
pub state: BeaconState<T::EthSpec>,
pub parent_block: SignedBeaconBlock<T::EthSpec>,
pub intermediate_states: StateBatch<T::EthSpec>,
}
/// Implemented on types that can be converted into a `FullyVerifiedBlock`.
///
/// Used to allow functions to accept blocks at various stages of verification.
pub trait IntoFullyVerifiedBlock<T: BeaconChainTypes> {
fn into_fully_verified_block(
self,
chain: &BeaconChain<T>,
) -> Result<FullyVerifiedBlock<T>, BlockError>;
fn block(&self) -> &SignedBeaconBlock<T::EthSpec>;
}
impl<T: BeaconChainTypes> GossipVerifiedBlock<T> {
/// Instantiates `Self`, a wrapper that indicates the given `block` is safe to be re-gossiped
/// on the p2p network.
///
/// Returns an error if the block is invalid, or if the block was unable to be verified.
pub fn new(
block: SignedBeaconBlock<T::EthSpec>,
chain: &BeaconChain<T>,
) -> Result<Self, BlockError> {
// Do not gossip or process blocks from future slots.
let present_slot_with_tolerance = chain
.slot_clock
.now_with_future_tolerance(MAXIMUM_GOSSIP_CLOCK_DISPARITY)
.ok_or_else(|| BeaconChainError::UnableToReadSlot)?;
if block.slot() > present_slot_with_tolerance {
return Err(BlockError::FutureSlot {
present_slot: present_slot_with_tolerance,
block_slot: block.slot(),
});
}
// Do not gossip a block from a finalized slot.
check_block_against_finalized_slot(&block.message, chain)?;
// Check that we have not already received a block with a valid signature for this slot.
if chain
.observed_block_producers
.proposer_has_been_observed(&block.message)
.map_err(|e| BlockError::BeaconChainError(e.into()))?
{
return Err(BlockError::RepeatProposal {
proposer: block.message.proposer_index,
slot: block.message.slot,
});
}
let mut parent = load_parent(&block.message, chain)?;
let block_root = get_block_root(&block);
let state = cheap_state_advance_to_obtain_committees(
&mut parent.beacon_state,
block.slot(),
&chain.spec,
)?;
let signature_is_valid = {
let pubkey_cache = get_validator_pubkey_cache(chain)?;
let pubkey = pubkey_cache
.get(block.message.proposer_index as usize)
.ok_or_else(|| BlockError::UnknownValidator(block.message.proposer_index))?;
block.verify_signature(
Some(block_root),
pubkey,
&state.fork,
chain.genesis_validators_root,
&chain.spec,
)
};
if !signature_is_valid {
return Err(BlockError::ProposalSignatureInvalid);
}
// Now the signature is valid, store the proposal so we don't accept another from this
// validator and slot.
//
// It's important to double-check that the proposer still hasn't been observed so we don't
// have a race-condition when verifying two blocks simultaneously.
if chain
.observed_block_producers
.observe_proposer(&block.message)
.map_err(|e| BlockError::BeaconChainError(e.into()))?
{
return Err(BlockError::RepeatProposal {
proposer: block.message.proposer_index,
slot: block.message.slot,
});
}
let expected_proposer =
state.get_beacon_proposer_index(block.message.slot, &chain.spec)? as u64;
if block.message.proposer_index != expected_proposer {
return Err(BlockError::IncorrectBlockProposer {
block: block.message.proposer_index,
local_shuffling: expected_proposer,
});
}
Ok(Self {
block,
block_root,
parent,
})
}
pub fn block_root(&self) -> Hash256 {
self.block_root
}
}
impl<T: BeaconChainTypes> IntoFullyVerifiedBlock<T> for GossipVerifiedBlock<T> {
/// Completes verification of the wrapped `block`.
fn into_fully_verified_block(
self,
chain: &BeaconChain<T>,
) -> Result<FullyVerifiedBlock<T>, BlockError> {
let fully_verified = SignatureVerifiedBlock::from_gossip_verified_block(self, chain)?;
fully_verified.into_fully_verified_block(chain)
}
fn block(&self) -> &SignedBeaconBlock<T::EthSpec> {
&self.block
}
}
impl<T: BeaconChainTypes> SignatureVerifiedBlock<T> {
/// Instantiates `Self`, a wrapper that indicates that all signatures (except the deposit
/// signatures) are valid (i.e., signed by the correct public keys).
///
/// Returns an error if the block is invalid, or if the block was unable to be verified.
pub fn new(
block: SignedBeaconBlock<T::EthSpec>,
chain: &BeaconChain<T>,
) -> Result<Self, BlockError> {
let mut parent = load_parent(&block.message, chain)?;
let block_root = get_block_root(&block);
let state = cheap_state_advance_to_obtain_committees(
&mut parent.beacon_state,
block.slot(),
&chain.spec,
)?;
let pubkey_cache = get_validator_pubkey_cache(chain)?;
let mut signature_verifier = get_signature_verifier(&state, &pubkey_cache, &chain.spec);
signature_verifier.include_all_signatures(&block, Some(block_root))?;
if signature_verifier.verify().is_ok() {
Ok(Self {
block,
block_root,
parent: Some(parent),
})
} else {
Err(BlockError::InvalidSignature)
}
}
/// Finishes signature verification on the provided `GossipVerifedBlock`. Does not re-verify
/// the proposer signature.
pub fn from_gossip_verified_block(
from: GossipVerifiedBlock<T>,
chain: &BeaconChain<T>,
) -> Result<Self, BlockError> {
let mut parent = from.parent;
let block = from.block;
let state = cheap_state_advance_to_obtain_committees(
&mut parent.beacon_state,
block.slot(),
&chain.spec,
)?;
let pubkey_cache = get_validator_pubkey_cache(chain)?;
let mut signature_verifier = get_signature_verifier(&state, &pubkey_cache, &chain.spec);
signature_verifier.include_all_signatures_except_proposal(&block)?;
if signature_verifier.verify().is_ok() {
Ok(Self {
block,
block_root: from.block_root,
parent: Some(parent),
})
} else {
Err(BlockError::InvalidSignature)
}
}
}
impl<T: BeaconChainTypes> IntoFullyVerifiedBlock<T> for SignatureVerifiedBlock<T> {
/// Completes verification of the wrapped `block`.
fn into_fully_verified_block(
self,
chain: &BeaconChain<T>,
) -> Result<FullyVerifiedBlock<T>, BlockError> {
let block = self.block;
let parent = self
.parent
.map(Result::Ok)
.unwrap_or_else(|| load_parent(&block.message, chain))?;
FullyVerifiedBlock::from_signature_verified_components(
block,
self.block_root,
parent,
chain,
)
}
fn block(&self) -> &SignedBeaconBlock<T::EthSpec> {
&self.block
}
}
impl<T: BeaconChainTypes> IntoFullyVerifiedBlock<T> for SignedBeaconBlock<T::EthSpec> {
/// Verifies the `SignedBeaconBlock` by first transforming it into a `SignatureVerifiedBlock`
/// and then using that implementation of `IntoFullyVerifiedBlock` to complete verification.
fn into_fully_verified_block(
self,
chain: &BeaconChain<T>,
) -> Result<FullyVerifiedBlock<T>, BlockError> {
SignatureVerifiedBlock::new(self, chain)?.into_fully_verified_block(chain)
}
fn block(&self) -> &SignedBeaconBlock<T::EthSpec> {
&self
}
}
impl<T: BeaconChainTypes> FullyVerifiedBlock<T> {
/// Instantiates `Self`, a wrapper that indicates that the given `block` is fully valid. See
/// the struct-level documentation for more information.
///
/// Note: this function does not verify block signatures, it assumes they are valid. Signature
/// verification must be done upstream (e.g., via a `SignatureVerifiedBlock`
///
/// Returns an error if the block is invalid, or if the block was unable to be verified.
pub fn from_signature_verified_components(
block: SignedBeaconBlock<T::EthSpec>,
block_root: Hash256,
parent: BeaconSnapshot<T::EthSpec>,
chain: &BeaconChain<T>,
) -> Result<Self, BlockError> {
// Reject any block if its parent is not known to fork choice.
//
// A block that is not in fork choice is either:
//
// - Not yet imported: we should reject this block because we should only import a child
// after its parent has been fully imported.
// - Pre-finalized: if the parent block is _prior_ to finalization, we should ignore it
// because it will revert finalization. Note that the finalized block is stored in fork
// choice, so we will not reject any child of the finalized block (this is relevant during
// genesis).
if !chain.fork_choice.contains_block(&block.parent_root()) {
return Err(BlockError::ParentUnknown(block.parent_root()));
}
/*
* Perform cursory checks to see if the block is even worth processing.
*/
check_block_relevancy(&block, Some(block_root), chain)?;
/*
* Advance the given `parent.beacon_state` to the slot of the given `block`.
*/
let catchup_timer = metrics::start_timer(&metrics::BLOCK_PROCESSING_CATCHUP_STATE);
// Keep a batch of any states that were "skipped" (block-less) in between the parent state
// slot and the block slot. These will be stored in the database.
let mut intermediate_states = StateBatch::new();
// The block must have a higher slot than its parent.
if block.slot() <= parent.beacon_state.slot {
return Err(BlockError::BlockIsNotLaterThanParent {
block_slot: block.slot(),
state_slot: parent.beacon_state.slot,
});
}
let mut summaries = vec![];
// Transition the parent state to the block slot.
let mut state = parent.beacon_state;
let distance = block.slot().as_u64().saturating_sub(state.slot.as_u64());
for i in 0..distance {
let state_root = if i == 0 {
parent.beacon_block.state_root()
} else {
// This is a new state we've reached, so stage it for storage in the DB.
// Computing the state root here is time-equivalent to computing it during slot
// processing, but we get early access to it.
let state_root = state.update_tree_hash_cache()?;
intermediate_states.add_state(state_root, &state)?;
state_root
};
per_slot_processing(&mut state, Some(state_root), &chain.spec)?
.map(|summary| summaries.push(summary));
}
expose_participation_metrics(&summaries);
metrics::stop_timer(catchup_timer);
/*
* Build the committee caches on the state.
*/
let committee_timer = metrics::start_timer(&metrics::BLOCK_PROCESSING_COMMITTEE);
state.build_committee_cache(RelativeEpoch::Previous, &chain.spec)?;
state.build_committee_cache(RelativeEpoch::Current, &chain.spec)?;
metrics::stop_timer(committee_timer);
/*
* Perform `per_block_processing` on the block and state, returning early if the block is
* invalid.
*/
write_state(
&format!("state_pre_block_{}", block_root),
&state,
&chain.log,
);
write_block(&block, block_root, &chain.log);
let core_timer = metrics::start_timer(&metrics::BLOCK_PROCESSING_CORE);
if let Err(err) = per_block_processing(
&mut state,
&block,
Some(block_root),
// Signatures were verified earlier in this function.
BlockSignatureStrategy::NoVerification,
&chain.spec,
) {
match err {
// Capture `BeaconStateError` so that we can easily distinguish between a block
// that's invalid and one that caused an internal error.
BlockProcessingError::BeaconStateError(e) => return Err(e.into()),
other => return Err(BlockError::PerBlockProcessingError(other)),
}
};
metrics::stop_timer(core_timer);
/*
* Calculate the state root of the newly modified state
*/
let state_root_timer = metrics::start_timer(&metrics::BLOCK_PROCESSING_STATE_ROOT);
let state_root = state.update_tree_hash_cache()?;
metrics::stop_timer(state_root_timer);
write_state(
&format!("state_post_block_{}", block_root),
&state,
&chain.log,
);
/*
* Check to ensure the state root on the block matches the one we have calculated.
*/
if block.state_root() != state_root {
return Err(BlockError::StateRootMismatch {
block: block.state_root(),
local: state_root,
});
}
Ok(Self {
block,
block_root,
state,
parent_block: parent.beacon_block,
intermediate_states,
})
}
}
/// Returns `Ok(())` if the block is later than the finalized slot on `chain`.
///
/// Returns an error if the block is earlier or equal to the finalized slot, or there was an error
/// verifying that condition.
fn check_block_against_finalized_slot<T: BeaconChainTypes>(
block: &BeaconBlock<T::EthSpec>,
chain: &BeaconChain<T>,
) -> Result<(), BlockError> {
let finalized_slot = chain
.head_info()?
.finalized_checkpoint
.epoch
.start_slot(T::EthSpec::slots_per_epoch());
if block.slot <= finalized_slot {
Err(BlockError::WouldRevertFinalizedSlot {
block_slot: block.slot,
finalized_slot,
})
} else {
Ok(())
}
}
/// Performs simple, cheap checks to ensure that the block is relevant to be imported.
///
/// `Ok(block_root)` is returned if the block passes these checks and should progress with
/// verification (viz., it is relevant).
///
/// Returns an error if the block fails one of these checks (viz., is not relevant) or an error is
/// experienced whilst attempting to verify.
pub fn check_block_relevancy<T: BeaconChainTypes>(
signed_block: &SignedBeaconBlock<T::EthSpec>,
block_root: Option<Hash256>,
chain: &BeaconChain<T>,
) -> Result<Hash256, BlockError> {
let block = &signed_block.message;
// Do not process blocks from the future.
if block.slot > chain.slot()? {
return Err(BlockError::FutureSlot {
present_slot: chain.slot()?,
block_slot: block.slot,
});
}
// Do not re-process the genesis block.
if block.slot == 0 {
return Err(BlockError::GenesisBlock);
}
// This is an artificial (non-spec) restriction that provides some protection from overflow
// abuses.
if block.slot >= MAXIMUM_BLOCK_SLOT_NUMBER {
return Err(BlockError::BlockSlotLimitReached);
}
// Do not process a block from a finalized slot.
check_block_against_finalized_slot(block, chain)?;
let block_root = block_root.unwrap_or_else(|| get_block_root(&signed_block));
// Check if the block is already known. We know it is post-finalization, so it is
// sufficient to check the fork choice.
if chain.fork_choice.contains_block(&block_root) {
return Err(BlockError::BlockIsAlreadyKnown);
}
Ok(block_root)
}
/// Returns the canonical root of the given `block`.
///
/// Use this function to ensure that we report the block hashing time Prometheus metric.
pub fn get_block_root<E: EthSpec>(block: &SignedBeaconBlock<E>) -> Hash256 {
let block_root_timer = metrics::start_timer(&metrics::BLOCK_PROCESSING_BLOCK_ROOT);
let block_root = block.canonical_root();
metrics::stop_timer(block_root_timer);
block_root
}
/// Load the parent snapshot (block and state) of the given `block`.
///
/// Returns `Err(BlockError::ParentUnknown)` if the parent is not found, or if an error occurs
/// whilst attempting the operation.
fn load_parent<T: BeaconChainTypes>(
block: &BeaconBlock<T::EthSpec>,
chain: &BeaconChain<T>,
) -> Result<BeaconSnapshot<T::EthSpec>, BlockError> {
let db_read_timer = metrics::start_timer(&metrics::BLOCK_PROCESSING_DB_READ);
// Reject any block if its parent is not known to fork choice.
//
// A block that is not in fork choice is either:
//
// - Not yet imported: we should reject this block because we should only import a child
// after its parent has been fully imported.
// - Pre-finalized: if the parent block is _prior_ to finalization, we should ignore it
// because it will revert finalization. Note that the finalized block is stored in fork
// choice, so we will not reject any child of the finalized block (this is relevant during
// genesis).
if !chain.fork_choice.contains_block(&block.parent_root) {
return Err(BlockError::ParentUnknown(block.parent_root));
}
// Load the parent block and state from disk, returning early if it's not available.
let result = chain
.snapshot_cache
.try_write_for(BLOCK_PROCESSING_CACHE_LOCK_TIMEOUT)
.and_then(|mut snapshot_cache| snapshot_cache.try_remove(block.parent_root))
.map(|snapshot| Ok(Some(snapshot)))
.unwrap_or_else(|| {
// Load the blocks parent block from the database, returning invalid if that block is not
// found.
//
// We don't return a DBInconsistent error here since it's possible for a block to
// exist in fork choice but not in the database yet. In such a case we simply
// indicate that we don't yet know the parent.
let parent_block = if let Some(block) = chain.get_block(&block.parent_root)? {
block
} else {
return Ok(None);
};
// 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 = chain
.get_state(&parent_state_root, Some(parent_block.slot()))?
.ok_or_else(|| {
BeaconChainError::DBInconsistent(format!(
"Missing state {:?}",
parent_state_root
))
})?;
Ok(Some(BeaconSnapshot {
beacon_block: parent_block,
beacon_block_root: block.parent_root,
beacon_state: parent_state,
beacon_state_root: parent_state_root,
}))
})
.map_err(BlockError::BeaconChainError)?
.ok_or_else(|| BlockError::ParentUnknown(block.parent_root));
metrics::stop_timer(db_read_timer);
result
}
/// Performs a cheap (time-efficient) state advancement so the committees for `slot` can be
/// obtained from `state`.
///
/// The state advancement is "cheap" since it does not generate state roots. As a result, the
/// returned state might be holistically invalid but the committees will be correct (since they do
/// not rely upon state roots).
///
/// If the given `state` can already serve the `slot`, the committees will be built on the `state`
/// and `Cow::Borrowed(state)` will be returned. Otherwise, the state will be cloned, cheaply
/// advanced and then returned as a `Cow::Owned`. The end result is that the given `state` is never
/// mutated to be invalid (in fact, it is never changed beyond a simple committee cache build).
fn cheap_state_advance_to_obtain_committees<'a, E: EthSpec>(
state: &'a mut BeaconState<E>,
block_slot: Slot,
spec: &ChainSpec,
) -> Result<Cow<'a, BeaconState<E>>, BlockError> {
let block_epoch = block_slot.epoch(E::slots_per_epoch());
if state.current_epoch() == block_epoch {
state.build_committee_cache(RelativeEpoch::Current, spec)?;
Ok(Cow::Borrowed(state))
} else if state.slot > block_slot {
Err(BlockError::BlockIsNotLaterThanParent {
block_slot,
state_slot: state.slot,
})
} else {
let mut state = state.clone_with(CloneConfig::committee_caches_only());
while state.current_epoch() < block_epoch {
// Don't calculate state roots since they aren't required for calculating
// shuffling (achieved by providing Hash256::zero()).
per_slot_processing(&mut state, Some(Hash256::zero()), spec).map_err(|e| {
BlockError::BeaconChainError(BeaconChainError::SlotProcessingError(e))
})?;
}
state.build_committee_cache(RelativeEpoch::Current, spec)?;
Ok(Cow::Owned(state))
}
}
/// Obtains a read-locked `ValidatorPubkeyCache` from the `chain`.
fn get_validator_pubkey_cache<T: BeaconChainTypes>(
chain: &BeaconChain<T>,
) -> Result<RwLockReadGuard<ValidatorPubkeyCache>, BlockError> {
chain
.validator_pubkey_cache
.try_read_for(VALIDATOR_PUBKEY_CACHE_LOCK_TIMEOUT)
.ok_or_else(|| BeaconChainError::ValidatorPubkeyCacheLockTimeout)
.map_err(BlockError::BeaconChainError)
}
/// Produces an _empty_ `BlockSignatureVerifier`.
///
/// The signature verifier is empty because it does not yet have any of this block's signatures
/// added to it. Use `Self::apply_to_signature_verifier` to apply the signatures.
fn get_signature_verifier<'a, E: EthSpec>(
state: &'a BeaconState<E>,
validator_pubkey_cache: &'a ValidatorPubkeyCache,
spec: &'a ChainSpec,
) -> BlockSignatureVerifier<'a, E, impl Fn(usize) -> Option<Cow<'a, PublicKey>> + Clone> {
BlockSignatureVerifier::new(
state,
move |validator_index| {
// Disallow access to any validator pubkeys that are not in the current beacon
// state.
if validator_index < state.validators.len() {
validator_pubkey_cache
.get(validator_index)
.map(|pk| Cow::Borrowed(pk))
} else {
None
}
},
spec,
)
}
fn expose_participation_metrics(summaries: &[EpochProcessingSummary]) {
if !cfg!(feature = "participation_metrics") {
return;
}
for summary in summaries {
let b = &summary.total_balances;
metrics::maybe_set_float_gauge(
&metrics::PARTICIPATION_PREV_EPOCH_ATTESTER,
participation_ratio(b.previous_epoch_attesters(), b.previous_epoch()),
);
metrics::maybe_set_float_gauge(
&metrics::PARTICIPATION_PREV_EPOCH_TARGET_ATTESTER,
participation_ratio(b.previous_epoch_target_attesters(), b.previous_epoch()),
);
metrics::maybe_set_float_gauge(
&metrics::PARTICIPATION_PREV_EPOCH_HEAD_ATTESTER,
participation_ratio(b.previous_epoch_head_attesters(), b.previous_epoch()),
);
}
}
fn participation_ratio(section: u64, total: u64) -> Option<f64> {
// Reduce the precision to help ensure we fit inside a u32.
const PRECISION: u64 = 100_000_000;
let section: f64 = u32::try_from(section / PRECISION).ok()?.into();
let total: f64 = u32::try_from(total / PRECISION).ok()?.into();
if total > 0_f64 {
Some(section / total)
} else {
None
}
}
fn write_state<T: EthSpec>(prefix: &str, state: &BeaconState<T>, log: &Logger) {
if WRITE_BLOCK_PROCESSING_SSZ {
let root = 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<T: EthSpec>(block: &SignedBeaconBlock<T>, root: Hash256, log: &Logger) {
if WRITE_BLOCK_PROCESSING_SSZ {
let filename = format!("block_slot_{}_root{}.ssz", block.message.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)
),
}
}
}