consensus/misc, params: add EIP-4844 blobfee conversions (#27041)

* consensus/misc, params: add EIP-4844 blobfee conversions

* consensus/misc: pull in fakeExponential test cases

* consensus/misc: reuse bigints

* consensus/misc: nit renames, additional larger testcase

---------

Co-authored-by: Roberto Bayardo <bayardo@alum.mit.edu>
Co-authored-by: Martin Holst Swende <martin@swende.se>
This commit is contained in:
Péter Szilágyi 2023-04-04 11:25:28 +03:00 committed by GitHub
parent 91faf2c559
commit d2cf49327f
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3 changed files with 142 additions and 0 deletions

54
consensus/misc/eip4844.go Normal file
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@ -0,0 +1,54 @@
// Copyright 2023 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package misc
import (
"math/big"
"github.com/ethereum/go-ethereum/params"
)
var (
minDataGasPrice = big.NewInt(params.BlobTxMinDataGasprice)
dataGaspriceUpdateFraction = big.NewInt(params.BlobTxDataGaspriceUpdateFraction)
)
// CalcBlobFee calculates the blobfee from the header's excess data gas field.
func CalcBlobFee(excessDataGas *big.Int) *big.Int {
// If this block does not yet have EIP-4844 enabled, return the starting fee
if excessDataGas == nil {
return big.NewInt(params.BlobTxMinDataGasprice)
}
return fakeExponential(minDataGasPrice, excessDataGas, dataGaspriceUpdateFraction)
}
// fakeExponential approximates factor * e ** (numerator / denominator) using
// Taylor expansion.
func fakeExponential(factor, numerator, denominator *big.Int) *big.Int {
var (
output = new(big.Int)
accum = new(big.Int).Mul(factor, denominator)
)
for i := 1; accum.Sign() > 0; i++ {
output.Add(output, accum)
accum.Mul(accum, numerator)
accum.Div(accum, denominator)
accum.Div(accum, big.NewInt(int64(i)))
}
return output.Div(output, denominator)
}

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@ -0,0 +1,85 @@
// Copyright 2023 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package misc
import (
"fmt"
"math/big"
"testing"
"github.com/ethereum/go-ethereum/params"
)
func TestCalcBlobFee(t *testing.T) {
tests := []struct {
excessDataGas int64
blobfee int64
}{
{0, 1},
{1542706, 1},
{1542707, 2},
{10 * 1024 * 1024, 111},
}
have := CalcBlobFee(nil)
if have.Int64() != params.BlobTxMinDataGasprice {
t.Errorf("nil test: blobfee mismatch: have %v, want %v", have, params.BlobTxMinDataGasprice)
}
for i, tt := range tests {
have := CalcBlobFee(big.NewInt(tt.excessDataGas))
if have.Int64() != tt.blobfee {
t.Errorf("test %d: blobfee mismatch: have %v want %v", i, have, tt.blobfee)
}
}
}
func TestFakeExponential(t *testing.T) {
tests := []struct {
factor int64
numerator int64
denominator int64
want int64
}{
// When numerator == 0 the return value should always equal the value of factor
{1, 0, 1, 1},
{38493, 0, 1000, 38493},
{0, 1234, 2345, 0}, // should be 0
{1, 2, 1, 6}, // approximate 7.389
{1, 4, 2, 6},
{1, 3, 1, 16}, // approximate 20.09
{1, 6, 2, 18},
{1, 4, 1, 49}, // approximate 54.60
{1, 8, 2, 50},
{10, 8, 2, 542}, // approximate 540.598
{11, 8, 2, 596}, // approximate 600.58
{1, 5, 1, 136}, // approximate 148.4
{1, 5, 2, 11}, // approximate 12.18
{2, 5, 2, 23}, // approximate 24.36
{1, 50000000, 2225652, 5709098764},
}
for i, tt := range tests {
f, n, d := big.NewInt(tt.factor), big.NewInt(tt.numerator), big.NewInt(tt.denominator)
original := fmt.Sprintf("%d %d %d", f, n, d)
have := fakeExponential(f, n, d)
if have.Int64() != tt.want {
t.Errorf("test %d: fake exponential mismatch: have %v want %v", i, have, tt.want)
}
later := fmt.Sprintf("%d %d %d", f, n, d)
if original != later {
t.Errorf("test %d: fake exponential modified arguments: have\n%v\nwant\n%v", i, later, original)
}
}
}

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@ -159,6 +159,9 @@ const (
// up to half the consumed gas could be refunded. Redefined as 1/5th in EIP-3529
RefundQuotient uint64 = 2
RefundQuotientEIP3529 uint64 = 5
BlobTxMinDataGasprice = 1 // Minimum gas price for data blobs
BlobTxDataGaspriceUpdateFraction = 2225652 // Controls the maximum rate of change for data gas price
)
// Gas discount table for BLS12-381 G1 and G2 multi exponentiation operations