[debate] configurable homestead block & genesis settings

cmd/evm/main.go

@@ -225,10 +225,15 @@ func (self *VMEnv) Call(caller vm.ContractRef, addr common.Address, data []byte,
 	self.Gas = gas
 	return core.Call(self, caller, addr, data, gas, price, value)
 }
+
 func (self *VMEnv) CallCode(caller vm.ContractRef, addr common.Address, data []byte, gas, price, value *big.Int) ([]byte, error) {
 	return core.CallCode(self, caller, addr, data, gas, price, value)
 }
 
+func (self *VMEnv) DelegateCall(caller vm.ContractRef, addr common.Address, data []byte, gas, price *big.Int) ([]byte, error) {
+	return core.DelegateCall(self, caller, addr, data, gas, price)
+}
+
 func (self *VMEnv) Create(caller vm.ContractRef, data []byte, gas, price, value *big.Int) ([]byte, common.Address, error) {
 	return core.Create(self, caller, data, gas, price, value)
 }

common/registrar/ethreg/api.go

@@ -23,14 +23,14 @@ import (
 	"github.com/ethereum/go-ethereum/accounts"
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/common/compiler"
+	"github.com/ethereum/go-ethereum/common/registrar"
 	"github.com/ethereum/go-ethereum/core"
 	"github.com/ethereum/go-ethereum/core/state"
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/ethdb"
 	"github.com/ethereum/go-ethereum/logger"
 	"github.com/ethereum/go-ethereum/logger/glog"
-	"github.com/ethereum/go-ethereum/common/registrar"
 )
 
 // registryAPIBackend is a backend for an Ethereum Registry.
@@ -112,6 +112,9 @@ type callmsg struct {
 func (m callmsg) From() (common.Address, error) {
 	return m.from.Address(), nil
 }
+func (m callmsg) FromFrontier() (common.Address, error) {
+	return m.from.Address(), nil
+}
 func (m callmsg) Nonce() uint64 {
 	return m.from.Nonce()
 }

core/bench_test.go

@@ -82,7 +82,7 @@ func genValueTx(nbytes int) func(int, *BlockGen) {
 	return func(i int, gen *BlockGen) {
 		toaddr := common.Address{}
 		data := make([]byte, nbytes)
-		gas := IntrinsicGas(data)
+		gas := IntrinsicGas(data, false, false)
 		tx, _ := types.NewTransaction(gen.TxNonce(benchRootAddr), toaddr, big.NewInt(1), gas, nil, data).SignECDSA(benchRootKey)
 		gen.AddTx(tx)
 	}

core/block_validator.go

@@ -30,6 +30,12 @@ import (
 	"gopkg.in/fatih/set.v0"
 )
 
+var (
+	ExpDiffPeriod = big.NewInt(100000)
+	big10         = big.NewInt(10)
+	bigMinus99    = big.NewInt(-99)
+)
+
 // BlockValidator is responsible for validating block headers, uncles and
 // processed state.
 //
@@ -111,7 +117,7 @@ func (v *BlockValidator) ValidateState(block, parent *types.Block, statedb *stat
 	// For valid blocks this should always validate to true.
 	rbloom := types.CreateBloom(receipts)
 	if rbloom != header.Bloom {
-		return fmt.Errorf("unable to replicate block's bloom=%x", rbloom)
+		return fmt.Errorf("unable to replicate block's bloom=%x vs calculated bloom=%x", header.Bloom, rbloom)
 	}
 	// Tre receipt Trie's root (R = (Tr [[H1, R1], ... [Hn, R1]]))
 	receiptSha := types.DeriveSha(receipts)
@@ -241,3 +247,127 @@ func ValidateHeader(pow pow.PoW, header *types.Header, parent *types.Header, che
 	}
 	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(time, parentTime uint64, parentNumber, parentDiff *big.Int) *big.Int {
+	if params.IsHomestead(new(big.Int).Add(parentNumber, common.Big1)) {
+		return calcDifficultyHomestead(time, parentTime, parentNumber, parentDiff)
+	} else {
+		return calcDifficultyFrontier(time, parentTime, parentNumber, parentDiff)
+	}
+}
+
+func calcDifficultyHomestead(time, parentTime uint64, parentNumber, parentDiff *big.Int) *big.Int {
+	// https://github.com/ethereum/EIPs/blob/master/EIPS/eip-2.mediawiki
+	// 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(parentTime)
+
+	// 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(common.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(parentDiff, params.DifficultyBoundDivisor)
+	x.Mul(y, x)
+	x.Add(parentDiff, x)
+
+	// minimum difficulty can ever be (before exponential factor)
+	if x.Cmp(params.MinimumDifficulty) < 0 {
+		x = params.MinimumDifficulty
+	}
+
+	// for the exponential factor
+	periodCount := new(big.Int).Add(parentNumber, common.Big1)
+	periodCount.Div(periodCount, ExpDiffPeriod)
+
+	// the exponential factor, commonly refered to as "the bomb"
+	// diff = diff + 2^(periodCount - 2)
+	if periodCount.Cmp(common.Big1) > 0 {
+		y.Sub(periodCount, common.Big2)
+		y.Exp(common.Big2, y, nil)
+		x.Add(x, y)
+	}
+
+	return x
+}
+
+func calcDifficultyFrontier(time, parentTime uint64, parentNumber, parentDiff *big.Int) *big.Int {
+	diff := new(big.Int)
+	adjust := new(big.Int).Div(parentDiff, params.DifficultyBoundDivisor)
+	bigTime := new(big.Int)
+	bigParentTime := new(big.Int)
+
+	bigTime.SetUint64(time)
+	bigParentTime.SetUint64(parentTime)
+
+	if bigTime.Sub(bigTime, bigParentTime).Cmp(params.DurationLimit) < 0 {
+		diff.Add(parentDiff, adjust)
+	} else {
+		diff.Sub(parentDiff, adjust)
+	}
+	if diff.Cmp(params.MinimumDifficulty) < 0 {
+		diff = params.MinimumDifficulty
+	}
+
+	periodCount := new(big.Int).Add(parentNumber, common.Big1)
+	periodCount.Div(periodCount, ExpDiffPeriod)
+	if periodCount.Cmp(common.Big1) > 0 {
+		// diff = diff + 2^(periodCount - 2)
+		expDiff := periodCount.Sub(periodCount, common.Big2)
+		expDiff.Exp(common.Big2, expDiff, nil)
+		diff.Add(diff, expDiff)
+		diff = common.BigMax(diff, params.MinimumDifficulty)
+	}
+
+	return diff
+}
+
+// CalcGasLimit computes the gas limit of the next block after parent.
+// The result may be modified by the caller.
+// This is miner strategy, not consensus protocol.
+func CalcGasLimit(parent *types.Block) *big.Int {
+	// contrib = (parentGasUsed * 3 / 2) / 1024
+	contrib := new(big.Int).Mul(parent.GasUsed(), big.NewInt(3))
+	contrib = contrib.Div(contrib, big.NewInt(2))
+	contrib = contrib.Div(contrib, params.GasLimitBoundDivisor)
+
+	// decay = parentGasLimit / 1024 -1
+	decay := new(big.Int).Div(parent.GasLimit(), params.GasLimitBoundDivisor)
+	decay.Sub(decay, big.NewInt(1))
+
+	/*
+		strategy: gasLimit of block-to-mine is set based on parent's
+		gasUsed value.  if parentGasUsed > parentGasLimit * (2/3) then we
+		increase it, otherwise lower it (or leave it unchanged if it's right
+		at that usage) the amount increased/decreased depends on how far away
+		from parentGasLimit * (2/3) parentGasUsed is.
+	*/
+	gl := new(big.Int).Sub(parent.GasLimit(), decay)
+	gl = gl.Add(gl, contrib)
+	gl.Set(common.BigMax(gl, params.MinGasLimit))
+
+	// however, if we're now below the target (GenesisGasLimit) we increase the
+	// limit as much as we can (parentGasLimit / 1024 -1)
+	if gl.Cmp(params.GenesisGasLimit) < 0 {
+		gl.Add(parent.GasLimit(), decay)
+		gl.Set(common.BigMin(gl, params.GenesisGasLimit))
+	}
+	return gl
+}

core/blockchain.go

@@ -725,14 +725,18 @@ func (self *BlockChain) writeHeader(header *types.Header) error {
 	if ptd == nil {
 		return ParentError(header.ParentHash)
 	}
-	td := new(big.Int).Add(header.Difficulty, ptd)
+
+	localTd := self.GetTd(self.currentHeader.Hash())
+	externTd := new(big.Int).Add(header.Difficulty, ptd)
 
 	// Make sure no inconsistent state is leaked during insertion
 	self.mu.Lock()
 	defer self.mu.Unlock()
 
 	// If the total difficulty is higher than our known, add it to the canonical chain
-	if td.Cmp(self.GetTd(self.currentHeader.Hash())) > 0 {
+	// Second clause in the if statement reduces the vulnerability to selfish mining.
+	// Please refer to http://www.cs.cornell.edu/~ie53/publications/btcProcFC.pdf
+	if externTd.Cmp(localTd) > 0 || (externTd.Cmp(localTd) == 0 && mrand.Float64() < 0.5) {
 		// Delete any canonical number assignments above the new head
 		for i := header.Number.Uint64() + 1; GetCanonicalHash(self.chainDb, i) != (common.Hash{}); i++ {
 			DeleteCanonicalHash(self.chainDb, i)
@@ -753,7 +757,7 @@ func (self *BlockChain) writeHeader(header *types.Header) error {
 		self.currentHeader = types.CopyHeader(header)
 	}
 	// Irrelevant of the canonical status, write the header itself to the database
-	if err := WriteTd(self.chainDb, header.Hash(), td); err != nil {
+	if err := WriteTd(self.chainDb, header.Hash(), externTd); err != nil {
 		glog.Fatalf("failed to write header total difficulty: %v", err)
 	}
 	if err := WriteHeader(self.chainDb, header); err != nil {
@@ -1060,14 +1064,18 @@ func (self *BlockChain) WriteBlock(block *types.Block) (status writeStatus, err
 	if ptd == nil {
 		return NonStatTy, ParentError(block.ParentHash())
 	}
-	td := new(big.Int).Add(block.Difficulty(), ptd)
+
+	localTd := self.GetTd(self.currentBlock.Hash())
+	externTd := new(big.Int).Add(block.Difficulty(), ptd)
 
 	// Make sure no inconsistent state is leaked during insertion
 	self.mu.Lock()
 	defer self.mu.Unlock()
 
 	// If the total difficulty is higher than our known, add it to the canonical chain
-	if td.Cmp(self.GetTd(self.currentBlock.Hash())) > 0 {
+	// Second clause in the if statement reduces the vulnerability to selfish mining.
+	// Please refer to http://www.cs.cornell.edu/~ie53/publications/btcProcFC.pdf
+	if externTd.Cmp(localTd) > 0 || (externTd.Cmp(localTd) == 0 && mrand.Float64() < 0.5) {
 		// Reorganize the chain if the parent is not the head block
 		if block.ParentHash() != self.currentBlock.Hash() {
 			if err := self.reorg(self.currentBlock, block); err != nil {
@@ -1081,7 +1089,7 @@ func (self *BlockChain) WriteBlock(block *types.Block) (status writeStatus, err
 		status = SideStatTy
 	}
 	// Irrelevant of the canonical status, write the block itself to the database
-	if err := WriteTd(self.chainDb, block.Hash(), td); err != nil {
+	if err := WriteTd(self.chainDb, block.Hash(), externTd); err != nil {
 		glog.Fatalf("failed to write block total difficulty: %v", err)
 	}
 	if err := WriteBlock(self.chainDb, block); err != nil {

core/database_util.go

@@ -27,7 +27,6 @@ import (
 	"github.com/ethereum/go-ethereum/ethdb"
 	"github.com/ethereum/go-ethereum/logger"
 	"github.com/ethereum/go-ethereum/logger/glog"
-	"github.com/ethereum/go-ethereum/params"
 	"github.com/ethereum/go-ethereum/rlp"
 )
 
@@ -50,77 +49,9 @@ var (
 	mipmapPre    = []byte("mipmap-log-bloom-")
 	MIPMapLevels = []uint64{1000000, 500000, 100000, 50000, 1000}
 
-	ExpDiffPeriod   = big.NewInt(100000)
 	blockHashPrefix = []byte("block-hash-") // [deprecated by the header/block split, remove eventually]
 )
 
-// CalcDifficulty is the difficulty adjustment algorithm. It returns
-// the difficulty that a new block b should have when created at time
-// given the parent block's time and difficulty.
-func CalcDifficulty(time, parentTime uint64, parentNumber, parentDiff *big.Int) *big.Int {
-	diff := new(big.Int)
-	adjust := new(big.Int).Div(parentDiff, params.DifficultyBoundDivisor)
-	bigTime := new(big.Int)
-	bigParentTime := new(big.Int)
-
-	bigTime.SetUint64(time)
-	bigParentTime.SetUint64(parentTime)
-
-	if bigTime.Sub(bigTime, bigParentTime).Cmp(params.DurationLimit) < 0 {
-		diff.Add(parentDiff, adjust)
-	} else {
-		diff.Sub(parentDiff, adjust)
-	}
-	if diff.Cmp(params.MinimumDifficulty) < 0 {
-		diff = params.MinimumDifficulty
-	}
-
-	periodCount := new(big.Int).Add(parentNumber, common.Big1)
-	periodCount.Div(periodCount, ExpDiffPeriod)
-	if periodCount.Cmp(common.Big1) > 0 {
-		// diff = diff + 2^(periodCount - 2)
-		expDiff := periodCount.Sub(periodCount, common.Big2)
-		expDiff.Exp(common.Big2, expDiff, nil)
-		diff.Add(diff, expDiff)
-		diff = common.BigMax(diff, params.MinimumDifficulty)
-	}
-
-	return diff
-}
-
-// CalcGasLimit computes the gas limit of the next block after parent.
-// The result may be modified by the caller.
-// This is miner strategy, not consensus protocol.
-func CalcGasLimit(parent *types.Block) *big.Int {
-	// contrib = (parentGasUsed * 3 / 2) / 1024
-	contrib := new(big.Int).Mul(parent.GasUsed(), big.NewInt(3))
-	contrib = contrib.Div(contrib, big.NewInt(2))
-	contrib = contrib.Div(contrib, params.GasLimitBoundDivisor)
-
-	// decay = parentGasLimit / 1024 -1
-	decay := new(big.Int).Div(parent.GasLimit(), params.GasLimitBoundDivisor)
-	decay.Sub(decay, big.NewInt(1))
-
-	/*
-		strategy: gasLimit of block-to-mine is set based on parent's
-		gasUsed value.  if parentGasUsed > parentGasLimit * (2/3) then we
-		increase it, otherwise lower it (or leave it unchanged if it's right
-		at that usage) the amount increased/decreased depends on how far away
-		from parentGasLimit * (2/3) parentGasUsed is.
-	*/
-	gl := new(big.Int).Sub(parent.GasLimit(), decay)
-	gl = gl.Add(gl, contrib)
-	gl.Set(common.BigMax(gl, params.MinGasLimit))
-
-	// however, if we're now below the target (GenesisGasLimit) we increase the
-	// limit as much as we can (parentGasLimit / 1024 -1)
-	if gl.Cmp(params.GenesisGasLimit) < 0 {
-		gl.Add(parent.GasLimit(), decay)
-		gl.Set(common.BigMin(gl, params.GenesisGasLimit))
-	}
-	return gl
-}
-
 // GetCanonicalHash retrieves a hash assigned to a canonical block number.
 func GetCanonicalHash(db ethdb.Database, number uint64) common.Hash {
 	data, _ := db.Get(append(blockNumPrefix, big.NewInt(int64(number)).Bytes()...))

core/database_util_test.go

@@ -62,7 +62,7 @@ func (d *diffTest) UnmarshalJSON(b []byte) (err error) {
 	return nil
 }
 
-func TestDifficulty(t *testing.T) {
+func TestDifficultyFrontier(t *testing.T) {
 	file, err := os.Open("../tests/files/BasicTests/difficulty.json")
 	if err != nil {
 		t.Fatal(err)
@@ -77,7 +77,7 @@ func TestDifficulty(t *testing.T) {
 
 	for name, test := range tests {
 		number := new(big.Int).Sub(test.CurrentBlocknumber, big.NewInt(1))
-		diff := CalcDifficulty(test.CurrentTimestamp, test.ParentTimestamp, number, test.ParentDifficulty)
+		diff := calcDifficultyFrontier(test.CurrentTimestamp, test.ParentTimestamp, number, test.ParentDifficulty)
 		if diff.Cmp(test.CurrentDifficulty) != 0 {
 			t.Error(name, "failed. Expected", test.CurrentDifficulty, "and calculated", diff)
 		}