github.com/DxChainNetwork/dxc@v0.8.1-0.20220824085222-1162e304b6e7/consensus/misc/gaslimit.go (about)

     1  // Copyright 2021 The go-ethereum Authors
     2  // This file is part of the go-ethereum library.
     3  //
     4  // The go-ethereum library is free software: you can redistribute it and/or modify
     5  // it under the terms of the GNU Lesser General Public License as published by
     6  // the Free Software Foundation, either version 3 of the License, or
     7  // (at your option) any later version.
     8  //
     9  // The go-ethereum library is distributed in the hope that it will be useful,
    10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
    11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    12  // GNU Lesser General Public License for more details.
    13  //
    14  // You should have received a copy of the GNU Lesser General Public License
    15  // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
    16  
    17  package misc
    18  
    19  import (
    20  	"errors"
    21  	"fmt"
    22  
    23  	"github.com/DxChainNetwork/dxc/params"
    24  )
    25  
    26  // VerifyGaslimit verifies the header gas limit according increase/decrease
    27  // in relation to the parent gas limit.
    28  func VerifyGaslimit(parentGasLimit, headerGasLimit uint64) error {
    29  	// Verify that the gas limit remains within allowed bounds
    30  	diff := int64(parentGasLimit) - int64(headerGasLimit)
    31  	if diff < 0 {
    32  		diff *= -1
    33  	}
    34  	limit := parentGasLimit / params.GasLimitBoundDivisor
    35  	if uint64(diff) >= limit {
    36  		return fmt.Errorf("invalid gas limit: have %d, want %d +-= %d", headerGasLimit, parentGasLimit, limit-1)
    37  	}
    38  	if headerGasLimit < params.MinGasLimit {
    39  		return errors.New("invalid gas limit below 5000")
    40  	}
    41  	return nil
    42  }