|
| 1 | +use alloy_primitives::U256; |
| 2 | + |
| 3 | +/// Ported from op-geth/ethapi/api.go |
| 4 | +/// Check if the transaction fee is reasonable (under the cap). |
| 5 | +/// |
| 6 | +/// # Arguments |
| 7 | +/// |
| 8 | +/// * `gas_price` - The gas price in wei as U256. |
| 9 | +/// * `gas` - The gas amount as U256. |
| 10 | +/// * `cap_in_wei` - The fee cap in wei as U256. |
| 11 | +/// |
| 12 | +/// # Returns |
| 13 | +/// |
| 14 | +/// * `Ok(())` if the fee is under the cap, or if there is no cap. |
| 15 | +/// * `Err(String)` with an error message if the fee exceeds the cap. |
| 16 | +pub fn check_tx_fee(gas_price: U256, gas: U256, cap_in_wei: U256) -> Result<(), String> { |
| 17 | + // Short circuit if there is no cap for transaction fee at all. |
| 18 | + if cap_in_wei.is_zero() { |
| 19 | + return Ok(()); |
| 20 | + } |
| 21 | + |
| 22 | + let fee_wei = gas_price |
| 23 | + .checked_mul(gas) |
| 24 | + .ok_or_else(|| "fee calculation overflow".to_string())?; |
| 25 | + |
| 26 | + if fee_wei > cap_in_wei { |
| 27 | + let gwei = U256::from(1_000_000_000u64); // 1 Gwei = 10^9 Wei |
| 28 | + let fee_gwei = fee_wei / gwei; |
| 29 | + let cap_gwei = cap_in_wei / gwei; |
| 30 | + Err(format!( |
| 31 | + "tx fee ({} gwei) exceeds the configured cap ({} gwei)", |
| 32 | + fee_gwei, cap_gwei |
| 33 | + )) |
| 34 | + } else { |
| 35 | + Ok(()) |
| 36 | + } |
| 37 | +} |
| 38 | + |
| 39 | +#[cfg(test)] |
| 40 | +mod tests { |
| 41 | + use super::*; |
| 42 | + |
| 43 | + const GWEI: U256 = U256::from_limbs([1_000_000_000, 0, 0, 0]); |
| 44 | + const ETHER: U256 = U256::from_limbs([1_000_000_000_000_000_000, 0, 0, 0]); |
| 45 | + |
| 46 | + #[test] |
| 47 | + fn test_no_cap() { |
| 48 | + assert!(check_tx_fee( |
| 49 | + U256::from(1_000_000_000u64), |
| 50 | + U256::from(21000u64), |
| 51 | + U256::ZERO |
| 52 | + ) |
| 53 | + .is_ok()); |
| 54 | + } |
| 55 | + |
| 56 | + #[test] |
| 57 | + fn test_under_cap() { |
| 58 | + assert!(check_tx_fee(U256::from(20_000_000_000u64), U256::from(21000u64), ETHER).is_ok()); |
| 59 | + } |
| 60 | + |
| 61 | + #[test] |
| 62 | + fn test_exact_cap() { |
| 63 | + let gas_price = U256::from(47619047619u64); // 47.619047619 Gwei |
| 64 | + let gas = U256::from(21000u64); |
| 65 | + let cap = gas_price * gas; |
| 66 | + assert!(check_tx_fee(gas_price, gas, cap).is_ok()); |
| 67 | + } |
| 68 | + |
| 69 | + #[test] |
| 70 | + fn test_over_cap() { |
| 71 | + let gas_price = U256::from(130u64); |
| 72 | + let gas = U256::from(20_123_000_123u64); |
| 73 | + let cap = GWEI * U256::from(1000u64); // 1000 Gwei |
| 74 | + let result = check_tx_fee(gas_price, gas, cap); |
| 75 | + assert!(result.is_err()); |
| 76 | + assert!(result |
| 77 | + .unwrap_err() |
| 78 | + .contains("tx fee (2615 gwei) exceeds the configured cap (1000 gwei)")); |
| 79 | + } |
| 80 | + |
| 81 | + #[test] |
| 82 | + fn test_large_values() { |
| 83 | + let gas_price = U256::MAX; |
| 84 | + let gas = U256::from(u64::MAX); |
| 85 | + let cap = U256::MAX; |
| 86 | + let result = check_tx_fee(gas_price, gas, cap); |
| 87 | + assert!(result.is_err()); // This will error due to overflow in fee calculation |
| 88 | + } |
| 89 | + |
| 90 | + #[test] |
| 91 | + fn test_small_values() { |
| 92 | + assert!(check_tx_fee(U256::from(1u64), U256::from(1u64), U256::from(2u64)).is_ok()); |
| 93 | + } |
| 94 | + |
| 95 | + #[test] |
| 96 | + fn test_zero_gas_price() { |
| 97 | + assert!(check_tx_fee(U256::ZERO, U256::from(21000u64), ETHER).is_ok()); |
| 98 | + } |
| 99 | + |
| 100 | + #[test] |
| 101 | + fn test_zero_gas() { |
| 102 | + assert!(check_tx_fee(U256::from(20_000_000_000u64), U256::ZERO, ETHER).is_ok()); |
| 103 | + } |
| 104 | + |
| 105 | + #[test] |
| 106 | + fn test_precision() { |
| 107 | + let gas_price = U256::from(20_000_000_000u64); // 20 Gwei |
| 108 | + let gas = U256::from(21_000u64); |
| 109 | + let fee = gas_price * gas; |
| 110 | + let cap_slightly_over = fee + U256::from(1u64); |
| 111 | + let cap_slightly_under = fee - U256::from(1u64); |
| 112 | + |
| 113 | + assert!(check_tx_fee(gas_price, gas, cap_slightly_over).is_ok()); |
| 114 | + assert!(check_tx_fee(gas_price, gas, cap_slightly_under).is_err()); |
| 115 | + } |
| 116 | + |
| 117 | + #[test] |
| 118 | + fn test_very_small_cap() { |
| 119 | + assert!(check_tx_fee(U256::from(1u64), U256::from(1u64), U256::from(1u64)).is_ok()); |
| 120 | + } |
| 121 | + |
| 122 | + #[test] |
| 123 | + fn test_very_large_cap() { |
| 124 | + // This test now uses large but not maximum values to avoid overflow |
| 125 | + let gas_price = U256::from(u64::MAX); |
| 126 | + let gas = U256::from(u64::MAX); |
| 127 | + let cap = U256::MAX; |
| 128 | + assert!(check_tx_fee(gas_price, gas, cap).is_ok()); // Will not fail |
| 129 | + } |
| 130 | + |
| 131 | + #[test] |
| 132 | + fn test_error_message_formatting() { |
| 133 | + let gas_price = U256::from(100u64); |
| 134 | + let gas = U256::from(1_600_000_000u64); |
| 135 | + let cap = GWEI * U256::from(150u64); // 150 Gwei |
| 136 | + let result = check_tx_fee(gas_price, gas, cap); |
| 137 | + assert!(result.is_err()); |
| 138 | + assert!(result |
| 139 | + .unwrap_err() |
| 140 | + .contains("tx fee (160 gwei) exceeds the configured cap (150 gwei)")); |
| 141 | + } |
| 142 | + |
| 143 | + #[test] |
| 144 | + fn test_fee_calculation_overflow() { |
| 145 | + let gas_price = U256::MAX; |
| 146 | + let gas = U256::from(2u64); |
| 147 | + let cap = U256::MAX; |
| 148 | + let result = check_tx_fee(gas_price, gas, cap); |
| 149 | + assert!(result.is_err()); |
| 150 | + assert_eq!(result.unwrap_err(), "fee calculation overflow"); |
| 151 | + } |
| 152 | +} |
0 commit comments