feb8f416ac
--------- Co-authored-by: Marius van der Wijden <m.vanderwijden@live.de> Co-authored-by: Felix Lange <fjl@twurst.com>
99 lines
3.6 KiB
Go
99 lines
3.6 KiB
Go
// Copyright 2023 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 eip4844
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import (
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"errors"
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"fmt"
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"math/big"
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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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var (
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minBlobGasPrice = big.NewInt(params.BlobTxMinBlobGasprice)
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blobGaspriceUpdateFraction = big.NewInt(params.BlobTxBlobGaspriceUpdateFraction)
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)
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// VerifyEIP4844Header verifies the presence of the excessBlobGas field and that
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// if the current block contains no transactions, the excessBlobGas is updated
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// accordingly.
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func VerifyEIP4844Header(parent, header *types.Header) error {
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// Verify the header is not malformed
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if header.ExcessBlobGas == nil {
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return errors.New("header is missing excessBlobGas")
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}
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if header.BlobGasUsed == nil {
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return errors.New("header is missing blobGasUsed")
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}
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// Verify that the blob gas used remains within reasonable limits.
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if *header.BlobGasUsed > params.MaxBlobGasPerBlock {
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return fmt.Errorf("blob gas used %d exceeds maximum allowance %d", *header.BlobGasUsed, params.MaxBlobGasPerBlock)
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}
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if *header.BlobGasUsed%params.BlobTxBlobGasPerBlob != 0 {
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return fmt.Errorf("blob gas used %d not a multiple of blob gas per blob %d", header.BlobGasUsed, params.BlobTxBlobGasPerBlob)
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}
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// Verify the excessBlobGas is correct based on the parent header
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var (
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parentExcessBlobGas uint64
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parentBlobGasUsed uint64
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)
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if parent.ExcessBlobGas != nil {
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parentExcessBlobGas = *parent.ExcessBlobGas
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parentBlobGasUsed = *parent.BlobGasUsed
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}
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expectedExcessBlobGas := CalcExcessBlobGas(parentExcessBlobGas, parentBlobGasUsed)
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if *header.ExcessBlobGas != expectedExcessBlobGas {
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return fmt.Errorf("invalid excessBlobGas: have %d, want %d, parent excessBlobGas %d, parent blobDataUsed %d",
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*header.ExcessBlobGas, expectedExcessBlobGas, parentExcessBlobGas, parentBlobGasUsed)
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}
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return nil
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}
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// CalcExcessBlobGas calculates the excess blob gas after applying the set of
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// blobs on top of the excess blob gas.
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func CalcExcessBlobGas(parentExcessBlobGas uint64, parentBlobGasUsed uint64) uint64 {
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excessBlobGas := parentExcessBlobGas + parentBlobGasUsed
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if excessBlobGas < params.BlobTxTargetBlobGasPerBlock {
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return 0
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}
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return excessBlobGas - params.BlobTxTargetBlobGasPerBlock
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}
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// CalcBlobFee calculates the blobfee from the header's excess blob gas field.
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func CalcBlobFee(excessBlobGas uint64) *big.Int {
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return fakeExponential(minBlobGasPrice, new(big.Int).SetUint64(excessBlobGas), blobGaspriceUpdateFraction)
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}
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// fakeExponential approximates factor * e ** (numerator / denominator) using
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// Taylor expansion.
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func fakeExponential(factor, numerator, denominator *big.Int) *big.Int {
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var (
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output = new(big.Int)
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accum = new(big.Int).Mul(factor, denominator)
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)
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for i := 1; accum.Sign() > 0; i++ {
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output.Add(output, accum)
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accum.Mul(accum, numerator)
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accum.Div(accum, denominator)
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accum.Div(accum, big.NewInt(int64(i)))
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}
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return output.Div(output, denominator)
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}
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