chore: add minimal protocol base fee (#2121)

crates/primitives/src/constants.rs

@@ -1,11 +1,21 @@
 //! Ethereum protocol-related constants
 
-use crate::H256;
+use crate::{H256, U256};
 use hex_literal::hex;
 
 /// The first four bytes of the call data for a function call specifies the function to be called.
 pub const SELECTOR_LEN: usize = 4;
 
+/// The minimal value the basefee can decrease to.
+///
+/// The `BASE_FEE_MAX_CHANGE_DENOMINATOR` <https://eips.ethereum.org/EIPS/eip-1559> is `8`, or 12.5%.
+/// Once the base fee has dropped to `7` WEI it cannot decrease further because 12.5% of 7 is less
+/// than 1.
+pub const MIN_PROTOCOL_BASE_FEE: u128 = 7;
+
+/// Same as [MIN_PROTOCOL_BASE_FEE] but as a U256.
+pub const MIN_PROTOCOL_BASE_FEE_U256: U256 = U256::from_limbs([7u64, 0, 0, 0]);
+
 /// Initial base fee as defined in [EIP-1559](https://eips.ethereum.org/EIPS/eip-1559)
 pub const EIP1559_INITIAL_BASE_FEE: u64 = 1_000_000_000;
 
@@ -56,3 +66,13 @@ pub const EMPTY_TRANSACTIONS: H256 = EMPTY_SET_HASH;
 
 /// Withdrawals root of empty withdrawals set.
 pub const EMPTY_WITHDRAWALS: H256 = EMPTY_SET_HASH;
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn min_protocol_sanity() {
+        assert_eq!(MIN_PROTOCOL_BASE_FEE_U256.to::<u128>(), MIN_PROTOCOL_BASE_FEE);
+    }
+}

crates/rpc/rpc-types/src/eth/engine/payload.rs

@@ -1,4 +1,5 @@
 use reth_primitives::{
+    constants::MIN_PROTOCOL_BASE_FEE_U256,
     proofs::{self, EMPTY_LIST_HASH},
     Address, Block, Bloom, Bytes, Header, SealedBlock, TransactionSigned, UintTryTo, Withdrawal,
     H256, U256, U64,
@@ -79,7 +80,7 @@ impl TryFrom<ExecutionPayload> for SealedBlock {
             return Err(PayloadError::ExtraData(payload.extra_data))
         }
 
-        if payload.base_fee_per_gas == U256::ZERO {
+        if payload.base_fee_per_gas < MIN_PROTOCOL_BASE_FEE_U256 {
             return Err(PayloadError::BaseFee(payload.base_fee_per_gas))
         }
 

crates/transaction-pool/src/pool/txpool.rs

@@ -17,7 +17,7 @@ use crate::{
     ValidPoolTransaction, U256,
 };
 use fnv::FnvHashMap;
-use reth_primitives::{TxHash, H256};
+use reth_primitives::{constants::MIN_PROTOCOL_BASE_FEE, TxHash, H256};
 use std::{
     cmp::Ordering,
     collections::{btree_map::Entry, hash_map, BTreeMap, HashMap},
@@ -26,13 +26,6 @@ use std::{
     sync::Arc,
 };
 
-/// The minimal value the basefee can decrease to.
-///
-/// The `BASE_FEE_MAX_CHANGE_DENOMINATOR` <https://eips.ethereum.org/EIPS/eip-1559> is `8`, or 12.5%.
-/// Once the base fee has dropped to `7` WEI it cannot decrease further because 12.5% of 7 is less
-/// than 1.
-pub(crate) const MIN_PROTOCOL_BASE_FEE: u128 = 7;
-
 /// A pool that manages transactions.
 ///
 /// This pool maintains the state of all transactions and stores them accordingly.

crates/transaction-pool/src/test_utils/mock.rs

@@ -2,7 +2,7 @@
 
 use crate::{
     identifier::{SenderIdentifiers, TransactionId},
-    pool::txpool::{TxPool, MIN_PROTOCOL_BASE_FEE},
+    pool::txpool::TxPool,
     traits::TransactionOrigin,
     PoolTransaction, TransactionOrdering, ValidPoolTransaction,
 };
@@ -12,8 +12,9 @@ use rand::{
     prelude::Distribution,
 };
 use reth_primitives::{
-    Address, FromRecoveredTransaction, IntoRecoveredTransaction, Transaction, TransactionKind,
-    TransactionSignedEcRecovered, TxEip1559, TxHash, TxLegacy, TxType, H256, U128, U256,
+    constants::MIN_PROTOCOL_BASE_FEE, Address, FromRecoveredTransaction, IntoRecoveredTransaction,
+    Transaction, TransactionKind, TransactionSignedEcRecovered, TxEip1559, TxHash, TxLegacy,
+    TxType, H256, U128, U256,
 };
 use std::{ops::Range, sync::Arc, time::Instant};