forked from cerc-io/plugeth
490c45c70f
* consensus/misc: reduce allocations in CalcBaseFee * consensus/misc: add formulas of CalcBaseFee
94 lines
3.5 KiB
Go
94 lines
3.5 KiB
Go
// Copyright 2021 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package misc
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import (
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"fmt"
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"math/big"
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"github.com/ethereum/go-ethereum/common"
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"github.com/ethereum/go-ethereum/common/math"
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"github.com/ethereum/go-ethereum/core/types"
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"github.com/ethereum/go-ethereum/params"
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)
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// VerifyEip1559Header verifies some header attributes which were changed in EIP-1559,
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// - gas limit check
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// - basefee check
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func VerifyEip1559Header(config *params.ChainConfig, parent, header *types.Header) error {
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// Verify that the gas limit remains within allowed bounds
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parentGasLimit := parent.GasLimit
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if !config.IsLondon(parent.Number) {
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parentGasLimit = parent.GasLimit * params.ElasticityMultiplier
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}
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if err := VerifyGaslimit(parentGasLimit, header.GasLimit); err != nil {
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return err
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}
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// Verify the header is not malformed
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if header.BaseFee == nil {
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return fmt.Errorf("header is missing baseFee")
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}
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// Verify the baseFee is correct based on the parent header.
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expectedBaseFee := CalcBaseFee(config, parent)
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if header.BaseFee.Cmp(expectedBaseFee) != 0 {
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return fmt.Errorf("invalid baseFee: have %s, want %s, parentBaseFee %s, parentGasUsed %d",
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header.BaseFee, expectedBaseFee, parent.BaseFee, parent.GasUsed)
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}
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return nil
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}
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// CalcBaseFee calculates the basefee of the header.
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func CalcBaseFee(config *params.ChainConfig, parent *types.Header) *big.Int {
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// If the current block is the first EIP-1559 block, return the InitialBaseFee.
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if !config.IsLondon(parent.Number) {
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return new(big.Int).SetUint64(params.InitialBaseFee)
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}
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parentGasTarget := parent.GasLimit / params.ElasticityMultiplier
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// If the parent gasUsed is the same as the target, the baseFee remains unchanged.
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if parent.GasUsed == parentGasTarget {
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return new(big.Int).Set(parent.BaseFee)
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}
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var (
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num = new(big.Int)
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denom = new(big.Int)
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)
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if parent.GasUsed > parentGasTarget {
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// If the parent block used more gas than its target, the baseFee should increase.
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// max(1, parentBaseFee * gasUsedDelta / parentGasTarget / baseFeeChangeDenominator)
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num.SetUint64(parent.GasUsed - parentGasTarget)
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num.Mul(num, parent.BaseFee)
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num.Div(num, denom.SetUint64(parentGasTarget))
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num.Div(num, denom.SetUint64(params.BaseFeeChangeDenominator))
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baseFeeDelta := math.BigMax(num, common.Big1)
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return num.Add(parent.BaseFee, baseFeeDelta)
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} else {
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// Otherwise if the parent block used less gas than its target, the baseFee should decrease.
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// max(0, parentBaseFee * gasUsedDelta / parentGasTarget / baseFeeChangeDenominator)
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num.SetUint64(parentGasTarget - parent.GasUsed)
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num.Mul(num, parent.BaseFee)
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num.Div(num, denom.SetUint64(parentGasTarget))
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num.Div(num, denom.SetUint64(params.BaseFeeChangeDenominator))
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baseFee := num.Sub(parent.BaseFee, num)
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return math.BigMax(baseFee, common.Big0)
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}
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}
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