Merge pull request #11 from han0110/fix/missing-difficulty

Fix: set missing difficulty in block header

minigeth/consensus/ethash/fake_ethash.go

@@ -5,6 +5,7 @@ import (
 	"math/big"
 
 	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/common/math"
 	"github.com/ethereum/go-ethereum/consensus"
 	"github.com/ethereum/go-ethereum/core/state"
 	"github.com/ethereum/go-ethereum/core/types"
@@ -17,8 +18,11 @@ func (ethash *Ethash) Author(header *types.Header) (common.Address, error) {
 	return header.Coinbase, nil
 }
 
+// CalcDifficulty 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.
 func (ethash *Ethash) CalcDifficulty(chain consensus.ChainHeaderReader, time uint64, parent *types.Header) *big.Int {
-	return nil
+	return CalcDifficulty(chain.Config(), time, parent)
 }
 
 func (ethash *Ethash) Close() error {
@@ -33,7 +37,6 @@ var (
 	maxUncles                     = 2                 // Maximum number of uncles allowed in a single block
 	allowedFutureBlockTimeSeconds = int64(15)         // Max seconds from current time allowed for blocks, before they're considered future blocks
 
-	/*
 	// calcDifficultyEip3554 is the difficulty adjustment algorithm as specified by EIP 3554.
 	// It offsets the bomb a total of 9.7M blocks.
 	// Specification EIP-3554: https://eips.ethereum.org/EIPS/eip-3554
@@ -55,7 +58,7 @@ var (
 	// the difficulty that a new block should have when created at time given the
 	// parent block's time and difficulty. The calculation uses the Byzantium rules.
 	// Specification EIP-649: https://eips.ethereum.org/EIPS/eip-649
-		calcDifficultyByzantium = makeDifficultyCalculator(big.NewInt(3000000))*/
+	calcDifficultyByzantium = makeDifficultyCalculator(big.NewInt(3000000))
 )
 
 // Some weird constants to avoid constant memory allocs for them.
@@ -131,3 +134,181 @@ func (ethash *Ethash) VerifyHeaders(chain consensus.ChainHeaderReader, headers [
 func (ethash *Ethash) VerifyUncles(chain consensus.ChainReader, block *types.Block) error {
 	return nil
 }
+
+// CalcDifficulty 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.
+func CalcDifficulty(config *params.ChainConfig, time uint64, parent *types.Header) *big.Int {
+	next := new(big.Int).Add(parent.Number, big1)
+	switch {
+	case config.IsCatalyst(next):
+		return big.NewInt(1)
+	case config.IsLondon(next):
+		return calcDifficultyEip3554(time, parent)
+	case config.IsMuirGlacier(next):
+		return calcDifficultyEip2384(time, parent)
+	case config.IsConstantinople(next):
+		return calcDifficultyConstantinople(time, parent)
+	case config.IsByzantium(next):
+		return calcDifficultyByzantium(time, parent)
+	case config.IsHomestead(next):
+		return calcDifficultyHomestead(time, parent)
+	default:
+		return calcDifficultyFrontier(time, parent)
+	}
+}
+
+// Some weird constants to avoid constant memory allocs for them.
+var (
+	expDiffPeriod = big.NewInt(100000)
+	big1          = big.NewInt(1)
+	big2          = big.NewInt(2)
+	big9          = big.NewInt(9)
+	big10         = big.NewInt(10)
+	bigMinus99    = big.NewInt(-99)
+)
+
+// makeDifficultyCalculator creates a difficultyCalculator with the given bomb-delay.
+// the difficulty is calculated with Byzantium rules, which differs from Homestead in
+// how uncles affect the calculation
+func makeDifficultyCalculator(bombDelay *big.Int) func(time uint64, parent *types.Header) *big.Int {
+	// Note, the calculations below looks at the parent number, which is 1 below
+	// the block number. Thus we remove one from the delay given
+	bombDelayFromParent := new(big.Int).Sub(bombDelay, big1)
+	return func(time uint64, parent *types.Header) *big.Int {
+		// https://github.com/ethereum/EIPs/issues/100.
+		// algorithm:
+		// diff = (parent_diff +
+		//         (parent_diff / 2048 * max((2 if len(parent.uncles) else 1) - ((timestamp - parent.timestamp) // 9), -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)
+
+		// (2 if len(parent_uncles) else 1) - (block_timestamp - parent_timestamp) // 9
+		x.Sub(bigTime, bigParentTime)
+		x.Div(x, big9)
+		if parent.UncleHash == types.EmptyUncleHash {
+			x.Sub(big1, x)
+		} else {
+			x.Sub(big2, x)
+		}
+		// max((2 if len(parent_uncles) else 1) - (block_timestamp - parent_timestamp) // 9, -99)
+		if x.Cmp(bigMinus99) < 0 {
+			x.Set(bigMinus99)
+		}
+		// parent_diff + (parent_diff / 2048 * max((2 if len(parent.uncles) else 1) - ((timestamp - parent.timestamp) // 9), -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)
+		}
+		// 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
+}

minigeth/main.go

@@ -68,6 +68,8 @@ func main() {
 	processor := core.NewStateProcessor(params.MainnetChainConfig, bc, bc.Engine())
 	fmt.Println("processing state:", parent.Number, "->", newheader.Number)
 
+	newheader.Difficulty = bc.Engine().CalcDifficulty(bc, newheader.Time, &parent)
+
 	// read txs
 	//traverseStackTrie(newheader.TxHash)
 

minigeth/oracle/prefetch.go

@@ -197,7 +197,7 @@ func Output(output common.Hash) {
 	if output == inputs[6] {
 		fmt.Println("good transition")
 	} else {
-		fmt.Println(output, "!=", inputs[5])
+		fmt.Println(output, "!=", inputs[6])
 		panic("BAD transition :((")
 	}
 }

minigeth/oracle/preimage.go

@@ -21,7 +21,7 @@ func Preimage(hash common.Hash) []byte {
 		fmt.Println("can't find preimage", hash)
 	}
 	comphash := crypto.Keccak256Hash(val)
-	if hash != comphash {
+	if ok && hash != comphash {
 		panic("corruption in hash " + hash.String())
 	}
 	return val