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chore: extract validate_against_parent_gas_limit into separate fn #18277

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Merged
mattsse merged 1 commit into from
Sep 4, 2025
Merged

chore: extract validate_against_parent_gas_limit into separate fn #18277

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52 changes: 50 additions & 2 deletions crates/consensus/common/src/validation.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -7,8 +7,8 @@ use alloy_eips::{eip4844::DATA_GAS_PER_BLOB, eip7840::BlobParams};
use reth_chainspec::{EthChainSpec, EthereumHardfork, EthereumHardforks};
use reth_consensus::ConsensusError;
use reth_primitives_traits::{
constants::MAXIMUM_GAS_LIMIT_BLOCK, Block, BlockBody, BlockHeader, GotExpected, SealedBlock,
SealedHeader,
constants::{GAS_LIMIT_BOUND_DIVISOR, MAXIMUM_GAS_LIMIT_BLOCK, MINIMUM_GAS_LIMIT},
Block, BlockBody, BlockHeader, GotExpected, SealedBlock, SealedHeader,
};

/// The maximum RLP length of a block, defined in [EIP-7934](https://eips.ethereum.org/EIPS/eip-7934).
Expand Down Expand Up @@ -329,6 +329,54 @@ pub fn validate_against_parent_timestamp<H: BlockHeader>(
Ok(())
}

/// Validates gas limit against parent gas limit.
///
/// The maximum allowable difference between self and parent gas limits is determined by the
/// parent's gas limit divided by the [`GAS_LIMIT_BOUND_DIVISOR`].
#[inline]
pub fn validate_against_parent_gas_limit<
H: BlockHeader,
ChainSpec: EthChainSpec + EthereumHardforks,
>(
header: &SealedHeader<H>,
parent: &SealedHeader<H>,
chain_spec: &ChainSpec,
) -> Result<(), ConsensusError> {
// Determine the parent gas limit, considering elasticity multiplier on the London fork.
let parent_gas_limit = if !chain_spec.is_london_active_at_block(parent.number()) &&
chain_spec.is_london_active_at_block(header.number())
{
parent.gas_limit() *
chain_spec.base_fee_params_at_timestamp(header.timestamp()).elasticity_multiplier
as u64
} else {
parent.gas_limit()
};

// Check for an increase in gas limit beyond the allowed threshold.
if header.gas_limit() > parent_gas_limit {
if header.gas_limit() - parent_gas_limit >= parent_gas_limit / GAS_LIMIT_BOUND_DIVISOR {
return Err(ConsensusError::GasLimitInvalidIncrease {
parent_gas_limit,
child_gas_limit: header.gas_limit(),
})
}
}
// Check for a decrease in gas limit beyond the allowed threshold.
else if parent_gas_limit - header.gas_limit() >= parent_gas_limit / GAS_LIMIT_BOUND_DIVISOR {
return Err(ConsensusError::GasLimitInvalidDecrease {
parent_gas_limit,
child_gas_limit: header.gas_limit(),
})
}
// Check if the self gas limit is below the minimum required limit.
else if header.gas_limit() < MINIMUM_GAS_LIMIT {
return Err(ConsensusError::GasLimitInvalidMinimum { child_gas_limit: header.gas_limit() })
}

Ok(())
}

/// Validates that the EIP-4844 header fields are correct with respect to the parent block. This
/// ensures that the `blob_gas_used` and `excess_blob_gas` fields exist in the child header, and
/// that the `excess_blob_gas` field matches the expected `excess_blob_gas` calculated from the
Expand Down
81 changes: 18 additions & 63 deletions crates/ethereum/consensus/src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -18,13 +18,13 @@ use reth_chainspec::{EthChainSpec, EthereumHardforks};
use reth_consensus::{Consensus, ConsensusError, FullConsensus, HeaderValidator};
use reth_consensus_common::validation::{
validate_4844_header_standalone, validate_against_parent_4844,
validate_against_parent_eip1559_base_fee, validate_against_parent_hash_number,
validate_against_parent_timestamp, validate_block_pre_execution, validate_body_against_header,
validate_header_base_fee, validate_header_extra_data, validate_header_gas,
validate_against_parent_eip1559_base_fee, validate_against_parent_gas_limit,
validate_against_parent_hash_number, validate_against_parent_timestamp,
validate_block_pre_execution, validate_body_against_header, validate_header_base_fee,
validate_header_extra_data, validate_header_gas,
};
use reth_execution_types::BlockExecutionResult;
use reth_primitives_traits::{
constants::{GAS_LIMIT_BOUND_DIVISOR, MINIMUM_GAS_LIMIT},
Block, BlockHeader, NodePrimitives, RecoveredBlock, SealedBlock, SealedHeader,
};

Expand All @@ -46,53 +46,9 @@ impl<ChainSpec: EthChainSpec + EthereumHardforks> EthBeaconConsensus<ChainSpec>
Self { chain_spec }
}

/// Checks the gas limit for consistency between parent and self headers.
///
/// The maximum allowable difference between self and parent gas limits is determined by the
/// parent's gas limit divided by the [`GAS_LIMIT_BOUND_DIVISOR`].
fn validate_against_parent_gas_limit<H: BlockHeader>(
&self,
header: &SealedHeader<H>,
parent: &SealedHeader<H>,
) -> Result<(), ConsensusError> {
// Determine the parent gas limit, considering elasticity multiplier on the London fork.
let parent_gas_limit = if !self.chain_spec.is_london_active_at_block(parent.number()) &&
self.chain_spec.is_london_active_at_block(header.number())
{
parent.gas_limit() *
self.chain_spec
.base_fee_params_at_timestamp(header.timestamp())
.elasticity_multiplier as u64
} else {
parent.gas_limit()
};

// Check for an increase in gas limit beyond the allowed threshold.
if header.gas_limit() > parent_gas_limit {
if header.gas_limit() - parent_gas_limit >= parent_gas_limit / GAS_LIMIT_BOUND_DIVISOR {
return Err(ConsensusError::GasLimitInvalidIncrease {
parent_gas_limit,
child_gas_limit: header.gas_limit(),
})
}
}
// Check for a decrease in gas limit beyond the allowed threshold.
else if parent_gas_limit - header.gas_limit() >=
parent_gas_limit / GAS_LIMIT_BOUND_DIVISOR
{
return Err(ConsensusError::GasLimitInvalidDecrease {
parent_gas_limit,
child_gas_limit: header.gas_limit(),
})
}
// Check if the self gas limit is below the minimum required limit.
else if header.gas_limit() < MINIMUM_GAS_LIMIT {
return Err(ConsensusError::GasLimitInvalidMinimum {
child_gas_limit: header.gas_limit(),
})
}

Ok(())
/// Returns the chain spec associated with this consensus engine.
pub const fn chain_spec(&self) -> &Arc<ChainSpec> {
&self.chain_spec
}
}

Expand Down Expand Up @@ -220,7 +176,7 @@ where

validate_against_parent_timestamp(header.header(), parent.header())?;

self.validate_against_parent_gas_limit(header, parent)?;
validate_against_parent_gas_limit(header, parent, &self.chain_spec)?;

validate_against_parent_eip1559_base_fee(
header.header(),
Expand All @@ -242,7 +198,11 @@ mod tests {
use super::*;
use alloy_primitives::B256;
use reth_chainspec::{ChainSpec, ChainSpecBuilder};
use reth_primitives_traits::proofs;
use reth_consensus_common::validation::validate_against_parent_gas_limit;
use reth_primitives_traits::{
constants::{GAS_LIMIT_BOUND_DIVISOR, MINIMUM_GAS_LIMIT},
proofs,
};

fn header_with_gas_limit(gas_limit: u64) -> SealedHeader {
let header = reth_primitives_traits::Header { gas_limit, ..Default::default() };
Expand All @@ -255,8 +215,7 @@ mod tests {
let child = header_with_gas_limit((parent.gas_limit + 5) as u64);

assert_eq!(
EthBeaconConsensus::new(Arc::new(ChainSpec::default()))
.validate_against_parent_gas_limit(&child, &parent),
validate_against_parent_gas_limit(&child, &parent, &ChainSpec::default()),
Ok(())
);
}
Expand All @@ -267,8 +226,7 @@ mod tests {
let child = header_with_gas_limit(MINIMUM_GAS_LIMIT - 1);

assert_eq!(
EthBeaconConsensus::new(Arc::new(ChainSpec::default()))
.validate_against_parent_gas_limit(&child, &parent),
validate_against_parent_gas_limit(&child, &parent, &ChainSpec::default()),
Err(ConsensusError::GasLimitInvalidMinimum { child_gas_limit: child.gas_limit as u64 })
);
}
Expand All @@ -281,8 +239,7 @@ mod tests {
);

assert_eq!(
EthBeaconConsensus::new(Arc::new(ChainSpec::default()))
.validate_against_parent_gas_limit(&child, &parent),
validate_against_parent_gas_limit(&child, &parent, &ChainSpec::default()),
Err(ConsensusError::GasLimitInvalidIncrease {
parent_gas_limit: parent.gas_limit,
child_gas_limit: child.gas_limit,
Expand All @@ -296,8 +253,7 @@ mod tests {
let child = header_with_gas_limit(parent.gas_limit - 5);

assert_eq!(
EthBeaconConsensus::new(Arc::new(ChainSpec::default()))
.validate_against_parent_gas_limit(&child, &parent),
validate_against_parent_gas_limit(&child, &parent, &ChainSpec::default()),
Ok(())
);
}
Expand All @@ -310,8 +266,7 @@ mod tests {
);

assert_eq!(
EthBeaconConsensus::new(Arc::new(ChainSpec::default()))
.validate_against_parent_gas_limit(&child, &parent),
validate_against_parent_gas_limit(&child, &parent, &ChainSpec::default()),
Err(ConsensusError::GasLimitInvalidDecrease {
parent_gas_limit: parent.gas_limit,
child_gas_limit: child.gas_limit,
Expand Down