* consensus/ethash, params: implement eip-2384: bump difficulty bomb * params: EIP 2384 compat checks * consensus, params: add Muir Glacier block number (mainnet,ropsten) + official name * core/forkid: forkid tests for muir glacier * params/config: address review concerns * params, core/forkid: review nitpicks * cmd/geth,eth,les: add override option for muir glacier * params: nit fix
		
			
				
	
	
		
			645 lines
		
	
	
		
			23 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
			
		
		
	
	
			645 lines
		
	
	
		
			23 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
// Copyright 2017 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 ethash
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import (
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	"bytes"
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	"errors"
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	"fmt"
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	"math/big"
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	"runtime"
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	"time"
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	mapset "github.com/deckarep/golang-set"
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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/consensus"
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	"github.com/ethereum/go-ethereum/consensus/misc"
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	"github.com/ethereum/go-ethereum/core/state"
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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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	"github.com/ethereum/go-ethereum/rlp"
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	"golang.org/x/crypto/sha3"
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)
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// Ethash proof-of-work protocol constants.
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var (
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	FrontierBlockReward       = big.NewInt(5e+18) // Block reward in wei for successfully mining a block
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	ByzantiumBlockReward      = big.NewInt(3e+18) // Block reward in wei for successfully mining a block upward from Byzantium
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	ConstantinopleBlockReward = big.NewInt(2e+18) // Block reward in wei for successfully mining a block upward from Constantinople
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	maxUncles                 = 2                 // Maximum number of uncles allowed in a single block
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	allowedFutureBlockTime    = 15 * time.Second  // Max time from current time allowed for blocks, before they're considered future blocks
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	// calcDifficultyEip2384 is the difficulty adjustment algorithm as specified by EIP 2384.
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	// It offsets the bomb 4M blocks from Constantinople, so in total 9M blocks.
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	// Specification EIP-2384: https://eips.ethereum.org/EIPS/eip-2384
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	calcDifficultyEip2384 = makeDifficultyCalculator(big.NewInt(9000000))
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	// calcDifficultyConstantinople is the difficulty adjustment algorithm for Constantinople.
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	// It returns the difficulty that a new block should have when created at time given the
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	// parent block's time and difficulty. The calculation uses the Byzantium rules, but with
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	// bomb offset 5M.
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	// Specification EIP-1234: https://eips.ethereum.org/EIPS/eip-1234
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	calcDifficultyConstantinople = makeDifficultyCalculator(big.NewInt(5000000))
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	// calcDifficultyByzantium is the difficulty adjustment algorithm. It returns
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	// the difficulty that a new block should have when created at time given the
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	// parent block's time and difficulty. The calculation uses the Byzantium rules.
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	// Specification EIP-649: https://eips.ethereum.org/EIPS/eip-649
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	calcDifficultyByzantium = makeDifficultyCalculator(big.NewInt(3000000))
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)
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// Various error messages to mark blocks invalid. These should be private to
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// prevent engine specific errors from being referenced in the remainder of the
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// codebase, inherently breaking if the engine is swapped out. Please put common
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// error types into the consensus package.
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var (
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	errZeroBlockTime     = errors.New("timestamp equals parent's")
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	errTooManyUncles     = errors.New("too many uncles")
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	errDuplicateUncle    = errors.New("duplicate uncle")
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	errUncleIsAncestor   = errors.New("uncle is ancestor")
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	errDanglingUncle     = errors.New("uncle's parent is not ancestor")
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	errInvalidDifficulty = errors.New("non-positive difficulty")
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	errInvalidMixDigest  = errors.New("invalid mix digest")
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	errInvalidPoW        = errors.New("invalid proof-of-work")
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)
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// Author implements consensus.Engine, returning the header's coinbase as the
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// proof-of-work verified author of the block.
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func (ethash *Ethash) Author(header *types.Header) (common.Address, error) {
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	return header.Coinbase, nil
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}
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// VerifyHeader checks whether a header conforms to the consensus rules of the
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// stock Ethereum ethash engine.
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func (ethash *Ethash) VerifyHeader(chain consensus.ChainReader, header *types.Header, seal bool) error {
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	// If we're running a full engine faking, accept any input as valid
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	if ethash.config.PowMode == ModeFullFake {
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		return nil
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	}
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	// Short circuit if the header is known, or its parent not
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	number := header.Number.Uint64()
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	if chain.GetHeader(header.Hash(), number) != nil {
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		return nil
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	}
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	parent := chain.GetHeader(header.ParentHash, number-1)
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	if parent == nil {
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		return consensus.ErrUnknownAncestor
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	}
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	// Sanity checks passed, do a proper verification
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	return ethash.verifyHeader(chain, header, parent, false, seal)
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}
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// VerifyHeaders is similar to VerifyHeader, but verifies a batch of headers
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// concurrently. The method returns a quit channel to abort the operations and
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// a results channel to retrieve the async verifications.
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func (ethash *Ethash) VerifyHeaders(chain consensus.ChainReader, headers []*types.Header, seals []bool) (chan<- struct{}, <-chan error) {
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	// If we're running a full engine faking, accept any input as valid
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	if ethash.config.PowMode == ModeFullFake || len(headers) == 0 {
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		abort, results := make(chan struct{}), make(chan error, len(headers))
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		for i := 0; i < len(headers); i++ {
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			results <- nil
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		}
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		return abort, results
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	}
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	// Spawn as many workers as allowed threads
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	workers := runtime.GOMAXPROCS(0)
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	if len(headers) < workers {
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		workers = len(headers)
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	}
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	// Create a task channel and spawn the verifiers
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	var (
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		inputs = make(chan int)
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		done   = make(chan int, workers)
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		errors = make([]error, len(headers))
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		abort  = make(chan struct{})
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	)
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	for i := 0; i < workers; i++ {
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		go func() {
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			for index := range inputs {
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				errors[index] = ethash.verifyHeaderWorker(chain, headers, seals, index)
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				done <- index
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			}
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		}()
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	}
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	errorsOut := make(chan error, len(headers))
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	go func() {
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		defer close(inputs)
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		var (
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			in, out = 0, 0
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			checked = make([]bool, len(headers))
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			inputs  = inputs
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		)
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		for {
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			select {
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			case inputs <- in:
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				if in++; in == len(headers) {
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					// Reached end of headers. Stop sending to workers.
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					inputs = nil
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				}
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			case index := <-done:
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				for checked[index] = true; checked[out]; out++ {
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					errorsOut <- errors[out]
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					if out == len(headers)-1 {
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						return
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					}
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				}
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			case <-abort:
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				return
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			}
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		}
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	}()
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	return abort, errorsOut
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}
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func (ethash *Ethash) verifyHeaderWorker(chain consensus.ChainReader, headers []*types.Header, seals []bool, index int) error {
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	var parent *types.Header
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	if index == 0 {
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		parent = chain.GetHeader(headers[0].ParentHash, headers[0].Number.Uint64()-1)
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	} else if headers[index-1].Hash() == headers[index].ParentHash {
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		parent = headers[index-1]
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	}
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	if parent == nil {
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		return consensus.ErrUnknownAncestor
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	}
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	if chain.GetHeader(headers[index].Hash(), headers[index].Number.Uint64()) != nil {
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		return nil // known block
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	}
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	return ethash.verifyHeader(chain, headers[index], parent, false, seals[index])
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}
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// VerifyUncles verifies that the given block's uncles conform to the consensus
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// rules of the stock Ethereum ethash engine.
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func (ethash *Ethash) VerifyUncles(chain consensus.ChainReader, block *types.Block) error {
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	// If we're running a full engine faking, accept any input as valid
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	if ethash.config.PowMode == ModeFullFake {
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		return nil
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	}
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	// Verify that there are at most 2 uncles included in this block
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	if len(block.Uncles()) > maxUncles {
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		return errTooManyUncles
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	}
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	if len(block.Uncles()) == 0 {
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		return nil
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	}
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	// Gather the set of past uncles and ancestors
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	uncles, ancestors := mapset.NewSet(), make(map[common.Hash]*types.Header)
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	number, parent := block.NumberU64()-1, block.ParentHash()
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	for i := 0; i < 7; i++ {
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		ancestor := chain.GetBlock(parent, number)
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		if ancestor == nil {
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			break
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		}
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		ancestors[ancestor.Hash()] = ancestor.Header()
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		for _, uncle := range ancestor.Uncles() {
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			uncles.Add(uncle.Hash())
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		}
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		parent, number = ancestor.ParentHash(), number-1
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	}
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	ancestors[block.Hash()] = block.Header()
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	uncles.Add(block.Hash())
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	// Verify each of the uncles that it's recent, but not an ancestor
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	for _, uncle := range block.Uncles() {
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		// Make sure every uncle is rewarded only once
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		hash := uncle.Hash()
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		if uncles.Contains(hash) {
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			return errDuplicateUncle
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		}
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		uncles.Add(hash)
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		// Make sure the uncle has a valid ancestry
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		if ancestors[hash] != nil {
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			return errUncleIsAncestor
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		}
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		if ancestors[uncle.ParentHash] == nil || uncle.ParentHash == block.ParentHash() {
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			return errDanglingUncle
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		}
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		if err := ethash.verifyHeader(chain, uncle, ancestors[uncle.ParentHash], true, true); err != nil {
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			return err
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		}
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	}
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	return nil
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}
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// verifyHeader checks whether a header conforms to the consensus rules of the
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// stock Ethereum ethash engine.
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// See YP section 4.3.4. "Block Header Validity"
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func (ethash *Ethash) verifyHeader(chain consensus.ChainReader, header, parent *types.Header, uncle bool, seal bool) error {
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	// Ensure that the header's extra-data section is of a reasonable size
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	if uint64(len(header.Extra)) > params.MaximumExtraDataSize {
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		return fmt.Errorf("extra-data too long: %d > %d", len(header.Extra), params.MaximumExtraDataSize)
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	}
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	// Verify the header's timestamp
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	if !uncle {
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		if header.Time > uint64(time.Now().Add(allowedFutureBlockTime).Unix()) {
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			return consensus.ErrFutureBlock
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		}
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	}
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	if header.Time <= parent.Time {
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		return errZeroBlockTime
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	}
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	// Verify the block's difficulty based in its timestamp and parent's difficulty
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	expected := ethash.CalcDifficulty(chain, header.Time, parent)
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	if expected.Cmp(header.Difficulty) != 0 {
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		return fmt.Errorf("invalid difficulty: have %v, want %v", header.Difficulty, expected)
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	}
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	// Verify that the gas limit is <= 2^63-1
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	cap := uint64(0x7fffffffffffffff)
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	if header.GasLimit > cap {
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		return fmt.Errorf("invalid gasLimit: have %v, max %v", header.GasLimit, cap)
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	}
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	// Verify that the gasUsed is <= gasLimit
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	if header.GasUsed > header.GasLimit {
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		return fmt.Errorf("invalid gasUsed: have %d, gasLimit %d", header.GasUsed, header.GasLimit)
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	}
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	// Verify that the gas limit remains within allowed bounds
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	diff := int64(parent.GasLimit) - int64(header.GasLimit)
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	if diff < 0 {
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		diff *= -1
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	}
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	limit := parent.GasLimit / params.GasLimitBoundDivisor
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	if uint64(diff) >= limit || header.GasLimit < params.MinGasLimit {
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		return fmt.Errorf("invalid gas limit: have %d, want %d += %d", header.GasLimit, parent.GasLimit, limit)
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	}
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	// Verify that the block number is parent's +1
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	if diff := new(big.Int).Sub(header.Number, parent.Number); diff.Cmp(big.NewInt(1)) != 0 {
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		return consensus.ErrInvalidNumber
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	}
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	// Verify the engine specific seal securing the block
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	if seal {
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		if err := ethash.VerifySeal(chain, header); err != nil {
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			return err
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		}
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	}
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	// If all checks passed, validate any special fields for hard forks
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	if err := misc.VerifyDAOHeaderExtraData(chain.Config(), header); err != nil {
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		return err
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	}
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	if err := misc.VerifyForkHashes(chain.Config(), header, uncle); err != nil {
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		return err
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	}
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	return nil
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}
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// CalcDifficulty is the difficulty adjustment algorithm. It returns
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// the difficulty that a new block should have when created at time
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// given the parent block's time and difficulty.
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func (ethash *Ethash) CalcDifficulty(chain consensus.ChainReader, time uint64, parent *types.Header) *big.Int {
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	return CalcDifficulty(chain.Config(), time, parent)
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}
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// CalcDifficulty is the difficulty adjustment algorithm. It returns
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// the difficulty that a new block should have when created at time
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// given the parent block's time and difficulty.
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func CalcDifficulty(config *params.ChainConfig, time uint64, parent *types.Header) *big.Int {
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	next := new(big.Int).Add(parent.Number, big1)
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	switch {
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	case config.IsMuirGlacier(next):
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		return calcDifficultyEip2384(time, parent)
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	case config.IsConstantinople(next):
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		return calcDifficultyConstantinople(time, parent)
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	case config.IsByzantium(next):
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		return calcDifficultyByzantium(time, parent)
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	case config.IsHomestead(next):
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		return calcDifficultyHomestead(time, parent)
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	default:
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		return calcDifficultyFrontier(time, parent)
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	}
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}
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// Some weird constants to avoid constant memory allocs for them.
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var (
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	expDiffPeriod = big.NewInt(100000)
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	big1          = big.NewInt(1)
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	big2          = big.NewInt(2)
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	big9          = big.NewInt(9)
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	big10         = big.NewInt(10)
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	bigMinus99    = big.NewInt(-99)
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)
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// makeDifficultyCalculator creates a difficultyCalculator with the given bomb-delay.
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// the difficulty is calculated with Byzantium rules, which differs from Homestead in
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// how uncles affect the calculation
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func makeDifficultyCalculator(bombDelay *big.Int) func(time uint64, parent *types.Header) *big.Int {
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	// Note, the calculations below looks at the parent number, which is 1 below
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	// the block number. Thus we remove one from the delay given
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	bombDelayFromParent := new(big.Int).Sub(bombDelay, big1)
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	return func(time uint64, parent *types.Header) *big.Int {
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		// https://github.com/ethereum/EIPs/issues/100.
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		// algorithm:
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		// diff = (parent_diff +
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		//         (parent_diff / 2048 * max((2 if len(parent.uncles) else 1) - ((timestamp - parent.timestamp) // 9), -99))
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		//        ) + 2^(periodCount - 2)
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		bigTime := new(big.Int).SetUint64(time)
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		bigParentTime := new(big.Int).SetUint64(parent.Time)
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		// holds intermediate values to make the algo easier to read & audit
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		x := new(big.Int)
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		y := new(big.Int)
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		// (2 if len(parent_uncles) else 1) - (block_timestamp - parent_timestamp) // 9
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		x.Sub(bigTime, bigParentTime)
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		x.Div(x, big9)
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		if parent.UncleHash == types.EmptyUncleHash {
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			x.Sub(big1, x)
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		} else {
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			x.Sub(big2, x)
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		}
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		// max((2 if len(parent_uncles) else 1) - (block_timestamp - parent_timestamp) // 9, -99)
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						|
		if x.Cmp(bigMinus99) < 0 {
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			x.Set(bigMinus99)
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		}
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		// parent_diff + (parent_diff / 2048 * max((2 if len(parent.uncles) else 1) - ((timestamp - parent.timestamp) // 9), -99))
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		y.Div(parent.Difficulty, params.DifficultyBoundDivisor)
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		x.Mul(y, x)
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		x.Add(parent.Difficulty, x)
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						|
		// minimum difficulty can ever be (before exponential factor)
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		if x.Cmp(params.MinimumDifficulty) < 0 {
 | 
						|
			x.Set(params.MinimumDifficulty)
 | 
						|
		}
 | 
						|
		// calculate a fake block number for the ice-age delay
 | 
						|
		// Specification: https://eips.ethereum.org/EIPS/eip-1234
 | 
						|
		fakeBlockNumber := new(big.Int)
 | 
						|
		if parent.Number.Cmp(bombDelayFromParent) >= 0 {
 | 
						|
			fakeBlockNumber = fakeBlockNumber.Sub(parent.Number, bombDelayFromParent)
 | 
						|
		}
 | 
						|
		// for the exponential factor
 | 
						|
		periodCount := fakeBlockNumber
 | 
						|
		periodCount.Div(periodCount, expDiffPeriod)
 | 
						|
 | 
						|
		// the exponential factor, commonly referred to as "the bomb"
 | 
						|
		// diff = diff + 2^(periodCount - 2)
 | 
						|
		if periodCount.Cmp(big1) > 0 {
 | 
						|
			y.Sub(periodCount, big2)
 | 
						|
			y.Exp(big2, y, nil)
 | 
						|
			x.Add(x, y)
 | 
						|
		}
 | 
						|
		return x
 | 
						|
	}
 | 
						|
}
 | 
						|
 | 
						|
// calcDifficultyHomestead is the difficulty adjustment algorithm. It returns
 | 
						|
// the difficulty that a new block should have when created at time given the
 | 
						|
// parent block's time and difficulty. The calculation uses the Homestead rules.
 | 
						|
func calcDifficultyHomestead(time uint64, parent *types.Header) *big.Int {
 | 
						|
	// https://github.com/ethereum/EIPs/blob/master/EIPS/eip-2.md
 | 
						|
	// algorithm:
 | 
						|
	// diff = (parent_diff +
 | 
						|
	//         (parent_diff / 2048 * max(1 - (block_timestamp - parent_timestamp) // 10, -99))
 | 
						|
	//        ) + 2^(periodCount - 2)
 | 
						|
 | 
						|
	bigTime := new(big.Int).SetUint64(time)
 | 
						|
	bigParentTime := new(big.Int).SetUint64(parent.Time)
 | 
						|
 | 
						|
	// holds intermediate values to make the algo easier to read & audit
 | 
						|
	x := new(big.Int)
 | 
						|
	y := new(big.Int)
 | 
						|
 | 
						|
	// 1 - (block_timestamp - parent_timestamp) // 10
 | 
						|
	x.Sub(bigTime, bigParentTime)
 | 
						|
	x.Div(x, big10)
 | 
						|
	x.Sub(big1, x)
 | 
						|
 | 
						|
	// max(1 - (block_timestamp - parent_timestamp) // 10, -99)
 | 
						|
	if x.Cmp(bigMinus99) < 0 {
 | 
						|
		x.Set(bigMinus99)
 | 
						|
	}
 | 
						|
	// (parent_diff + parent_diff // 2048 * max(1 - (block_timestamp - parent_timestamp) // 10, -99))
 | 
						|
	y.Div(parent.Difficulty, params.DifficultyBoundDivisor)
 | 
						|
	x.Mul(y, x)
 | 
						|
	x.Add(parent.Difficulty, x)
 | 
						|
 | 
						|
	// minimum difficulty can ever be (before exponential factor)
 | 
						|
	if x.Cmp(params.MinimumDifficulty) < 0 {
 | 
						|
		x.Set(params.MinimumDifficulty)
 | 
						|
	}
 | 
						|
	// for the exponential factor
 | 
						|
	periodCount := new(big.Int).Add(parent.Number, big1)
 | 
						|
	periodCount.Div(periodCount, expDiffPeriod)
 | 
						|
 | 
						|
	// the exponential factor, commonly referred to as "the bomb"
 | 
						|
	// diff = diff + 2^(periodCount - 2)
 | 
						|
	if periodCount.Cmp(big1) > 0 {
 | 
						|
		y.Sub(periodCount, big2)
 | 
						|
		y.Exp(big2, y, nil)
 | 
						|
		x.Add(x, y)
 | 
						|
	}
 | 
						|
	return x
 | 
						|
}
 | 
						|
 | 
						|
// calcDifficultyFrontier is the difficulty adjustment algorithm. It returns the
 | 
						|
// difficulty that a new block should have when created at time given the parent
 | 
						|
// block's time and difficulty. The calculation uses the Frontier rules.
 | 
						|
func calcDifficultyFrontier(time uint64, parent *types.Header) *big.Int {
 | 
						|
	diff := new(big.Int)
 | 
						|
	adjust := new(big.Int).Div(parent.Difficulty, params.DifficultyBoundDivisor)
 | 
						|
	bigTime := new(big.Int)
 | 
						|
	bigParentTime := new(big.Int)
 | 
						|
 | 
						|
	bigTime.SetUint64(time)
 | 
						|
	bigParentTime.SetUint64(parent.Time)
 | 
						|
 | 
						|
	if bigTime.Sub(bigTime, bigParentTime).Cmp(params.DurationLimit) < 0 {
 | 
						|
		diff.Add(parent.Difficulty, adjust)
 | 
						|
	} else {
 | 
						|
		diff.Sub(parent.Difficulty, adjust)
 | 
						|
	}
 | 
						|
	if diff.Cmp(params.MinimumDifficulty) < 0 {
 | 
						|
		diff.Set(params.MinimumDifficulty)
 | 
						|
	}
 | 
						|
 | 
						|
	periodCount := new(big.Int).Add(parent.Number, big1)
 | 
						|
	periodCount.Div(periodCount, expDiffPeriod)
 | 
						|
	if periodCount.Cmp(big1) > 0 {
 | 
						|
		// diff = diff + 2^(periodCount - 2)
 | 
						|
		expDiff := periodCount.Sub(periodCount, big2)
 | 
						|
		expDiff.Exp(big2, expDiff, nil)
 | 
						|
		diff.Add(diff, expDiff)
 | 
						|
		diff = math.BigMax(diff, params.MinimumDifficulty)
 | 
						|
	}
 | 
						|
	return diff
 | 
						|
}
 | 
						|
 | 
						|
// VerifySeal implements consensus.Engine, checking whether the given block satisfies
 | 
						|
// the PoW difficulty requirements.
 | 
						|
func (ethash *Ethash) VerifySeal(chain consensus.ChainReader, header *types.Header) error {
 | 
						|
	return ethash.verifySeal(chain, header, false)
 | 
						|
}
 | 
						|
 | 
						|
// verifySeal checks whether a block satisfies the PoW difficulty requirements,
 | 
						|
// either using the usual ethash cache for it, or alternatively using a full DAG
 | 
						|
// to make remote mining fast.
 | 
						|
func (ethash *Ethash) verifySeal(chain consensus.ChainReader, header *types.Header, fulldag bool) error {
 | 
						|
	// If we're running a fake PoW, accept any seal as valid
 | 
						|
	if ethash.config.PowMode == ModeFake || ethash.config.PowMode == ModeFullFake {
 | 
						|
		time.Sleep(ethash.fakeDelay)
 | 
						|
		if ethash.fakeFail == header.Number.Uint64() {
 | 
						|
			return errInvalidPoW
 | 
						|
		}
 | 
						|
		return nil
 | 
						|
	}
 | 
						|
	// If we're running a shared PoW, delegate verification to it
 | 
						|
	if ethash.shared != nil {
 | 
						|
		return ethash.shared.verifySeal(chain, header, fulldag)
 | 
						|
	}
 | 
						|
	// Ensure that we have a valid difficulty for the block
 | 
						|
	if header.Difficulty.Sign() <= 0 {
 | 
						|
		return errInvalidDifficulty
 | 
						|
	}
 | 
						|
	// Recompute the digest and PoW values
 | 
						|
	number := header.Number.Uint64()
 | 
						|
 | 
						|
	var (
 | 
						|
		digest []byte
 | 
						|
		result []byte
 | 
						|
	)
 | 
						|
	// If fast-but-heavy PoW verification was requested, use an ethash dataset
 | 
						|
	if fulldag {
 | 
						|
		dataset := ethash.dataset(number, true)
 | 
						|
		if dataset.generated() {
 | 
						|
			digest, result = hashimotoFull(dataset.dataset, ethash.SealHash(header).Bytes(), header.Nonce.Uint64())
 | 
						|
 | 
						|
			// Datasets are unmapped in a finalizer. Ensure that the dataset stays alive
 | 
						|
			// until after the call to hashimotoFull so it's not unmapped while being used.
 | 
						|
			runtime.KeepAlive(dataset)
 | 
						|
		} else {
 | 
						|
			// Dataset not yet generated, don't hang, use a cache instead
 | 
						|
			fulldag = false
 | 
						|
		}
 | 
						|
	}
 | 
						|
	// If slow-but-light PoW verification was requested (or DAG not yet ready), use an ethash cache
 | 
						|
	if !fulldag {
 | 
						|
		cache := ethash.cache(number)
 | 
						|
 | 
						|
		size := datasetSize(number)
 | 
						|
		if ethash.config.PowMode == ModeTest {
 | 
						|
			size = 32 * 1024
 | 
						|
		}
 | 
						|
		digest, result = hashimotoLight(size, cache.cache, ethash.SealHash(header).Bytes(), header.Nonce.Uint64())
 | 
						|
 | 
						|
		// Caches are unmapped in a finalizer. Ensure that the cache stays alive
 | 
						|
		// until after the call to hashimotoLight so it's not unmapped while being used.
 | 
						|
		runtime.KeepAlive(cache)
 | 
						|
	}
 | 
						|
	// Verify the calculated values against the ones provided in the header
 | 
						|
	if !bytes.Equal(header.MixDigest[:], digest) {
 | 
						|
		return errInvalidMixDigest
 | 
						|
	}
 | 
						|
	target := new(big.Int).Div(two256, header.Difficulty)
 | 
						|
	if new(big.Int).SetBytes(result).Cmp(target) > 0 {
 | 
						|
		return errInvalidPoW
 | 
						|
	}
 | 
						|
	return nil
 | 
						|
}
 | 
						|
 | 
						|
// Prepare implements consensus.Engine, initializing the difficulty field of a
 | 
						|
// header to conform to the ethash protocol. The changes are done inline.
 | 
						|
func (ethash *Ethash) Prepare(chain consensus.ChainReader, header *types.Header) error {
 | 
						|
	parent := chain.GetHeader(header.ParentHash, header.Number.Uint64()-1)
 | 
						|
	if parent == nil {
 | 
						|
		return consensus.ErrUnknownAncestor
 | 
						|
	}
 | 
						|
	header.Difficulty = ethash.CalcDifficulty(chain, header.Time, parent)
 | 
						|
	return nil
 | 
						|
}
 | 
						|
 | 
						|
// Finalize implements consensus.Engine, accumulating the block and uncle rewards,
 | 
						|
// setting the final state on the header
 | 
						|
func (ethash *Ethash) Finalize(chain consensus.ChainReader, header *types.Header, state *state.StateDB, txs []*types.Transaction, uncles []*types.Header) {
 | 
						|
	// Accumulate any block and uncle rewards and commit the final state root
 | 
						|
	accumulateRewards(chain.Config(), state, header, uncles)
 | 
						|
	header.Root = state.IntermediateRoot(chain.Config().IsEIP158(header.Number))
 | 
						|
}
 | 
						|
 | 
						|
// FinalizeAndAssemble implements consensus.Engine, accumulating the block and
 | 
						|
// uncle rewards, setting the final state and assembling the block.
 | 
						|
func (ethash *Ethash) FinalizeAndAssemble(chain consensus.ChainReader, header *types.Header, state *state.StateDB, txs []*types.Transaction, uncles []*types.Header, receipts []*types.Receipt) (*types.Block, error) {
 | 
						|
	// Accumulate any block and uncle rewards and commit the final state root
 | 
						|
	accumulateRewards(chain.Config(), state, header, uncles)
 | 
						|
	header.Root = state.IntermediateRoot(chain.Config().IsEIP158(header.Number))
 | 
						|
 | 
						|
	// Header seems complete, assemble into a block and return
 | 
						|
	return types.NewBlock(header, txs, uncles, receipts), nil
 | 
						|
}
 | 
						|
 | 
						|
// SealHash returns the hash of a block prior to it being sealed.
 | 
						|
func (ethash *Ethash) SealHash(header *types.Header) (hash common.Hash) {
 | 
						|
	hasher := sha3.NewLegacyKeccak256()
 | 
						|
 | 
						|
	rlp.Encode(hasher, []interface{}{
 | 
						|
		header.ParentHash,
 | 
						|
		header.UncleHash,
 | 
						|
		header.Coinbase,
 | 
						|
		header.Root,
 | 
						|
		header.TxHash,
 | 
						|
		header.ReceiptHash,
 | 
						|
		header.Bloom,
 | 
						|
		header.Difficulty,
 | 
						|
		header.Number,
 | 
						|
		header.GasLimit,
 | 
						|
		header.GasUsed,
 | 
						|
		header.Time,
 | 
						|
		header.Extra,
 | 
						|
	})
 | 
						|
	hasher.Sum(hash[:0])
 | 
						|
	return hash
 | 
						|
}
 | 
						|
 | 
						|
// Some weird constants to avoid constant memory allocs for them.
 | 
						|
var (
 | 
						|
	big8  = big.NewInt(8)
 | 
						|
	big32 = big.NewInt(32)
 | 
						|
)
 | 
						|
 | 
						|
// AccumulateRewards credits the coinbase of the given block with the mining
 | 
						|
// reward. The total reward consists of the static block reward and rewards for
 | 
						|
// included uncles. The coinbase of each uncle block is also rewarded.
 | 
						|
func accumulateRewards(config *params.ChainConfig, state *state.StateDB, header *types.Header, uncles []*types.Header) {
 | 
						|
	// Select the correct block reward based on chain progression
 | 
						|
	blockReward := FrontierBlockReward
 | 
						|
	if config.IsByzantium(header.Number) {
 | 
						|
		blockReward = ByzantiumBlockReward
 | 
						|
	}
 | 
						|
	if config.IsConstantinople(header.Number) {
 | 
						|
		blockReward = ConstantinopleBlockReward
 | 
						|
	}
 | 
						|
	// Accumulate the rewards for the miner and any included uncles
 | 
						|
	reward := new(big.Int).Set(blockReward)
 | 
						|
	r := new(big.Int)
 | 
						|
	for _, uncle := range uncles {
 | 
						|
		r.Add(uncle.Number, big8)
 | 
						|
		r.Sub(r, header.Number)
 | 
						|
		r.Mul(r, blockReward)
 | 
						|
		r.Div(r, big8)
 | 
						|
		state.AddBalance(uncle.Coinbase, r)
 | 
						|
 | 
						|
		r.Div(blockReward, big32)
 | 
						|
		reward.Add(reward, r)
 | 
						|
	}
 | 
						|
	state.AddBalance(header.Coinbase, reward)
 | 
						|
}
 |