parmas, crypto, core, core/vm: homestead consensus protocol changes

* change gas cost for contract creating txs
* invalidate signature with s value greater than secp256k1 N / 2
* OOG contract creation if not enough gas to store code
* new difficulty adjustment algorithm
* new DELEGATECALL op code

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)
 }

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.
 //
@@ -111,6 +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 {
+		//fmt.Printf("FUNKY: ValidateState: block number: %v\n", block.Number())
 		return fmt.Errorf("unable to replicate block's bloom=%x", rbloom)
 	}
 	// Tre receipt Trie's root (R = (Tr [[H1, R1], ... [Hn, R1]]))
@@ -241,3 +248,127 @@ 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)
+
+	// for the exponential factor
+	periodCount := new(big.Int).Add(parentNumber, common.Big1)
+	periodCount.Div(periodCount, ExpDiffPeriod)
+
+	// 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
+	}
+
+	// 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/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()...))
@@ -164,6 +95,20 @@ func GetHeadFastBlockHash(db ethdb.Database) common.Hash {
 	return common.BytesToHash(data)
 }
 
+// GetHeadBlockNum retrieves the block number of the current canonical head block.
+func GetHeadBlockNum(db ethdb.Database) *big.Int {
+	data, _ := db.Get(headBlockKey)
+	if len(data) == 0 {
+		return nil
+	}
+	header := new(types.Header)
+	if err := rlp.Decode(bytes.NewReader(data), header); err != nil {
+		glog.V(logger.Error).Infof("invalid block header RLP for head block: %v", err)
+		return nil
+	}
+	return header.Number
+}
+
 // GetHeaderRLP retrieves a block header in its raw RLP database encoding, or nil
 // if the header's not found.
 func GetHeaderRLP(db ethdb.Database, hash common.Hash) rlp.RawValue {

core/execution.go

@@ -33,8 +33,18 @@ func Call(env vm.Environment, caller vm.ContractRef, addr common.Address, input
 
 // CallCode executes the given address' code as the given contract address
 func CallCode(env vm.Environment, caller vm.ContractRef, addr common.Address, input []byte, gas, gasPrice, value *big.Int) (ret []byte, err error) {
-	prev := caller.Address()
-	ret, _, err = exec(env, caller, &prev, &addr, input, env.Db().GetCode(addr), gas, gasPrice, value)
+	callerAddr := caller.Address()
+	ret, _, err = exec(env, caller, &callerAddr, &addr, input, env.Db().GetCode(addr), gas, gasPrice, value)
+	return ret, err
+}
+
+// DelegateCall is equivalent to CallCode except that sender and value propagates from parent scope to child scope
+func DelegateCall(env vm.Environment, caller vm.ContractRef, addr common.Address, input []byte, gas, gasPrice *big.Int) (ret []byte, err error) {
+	callerAddr := caller.Address()
+	originAddr := env.Origin()
+	callerValue := caller.Value()
+	ret, _, err = execDelegateCall(env, caller, &originAddr, &callerAddr, &addr, input, env.Db().GetCode(addr), gas, gasPrice, callerValue)
+	caller.SetAddress(callerAddr)
 	return ret, err
 }
 
@@ -52,7 +62,6 @@ func Create(env vm.Environment, caller vm.ContractRef, code []byte, gas, gasPric
 
 func exec(env vm.Environment, caller vm.ContractRef, address, codeAddr *common.Address, input, code []byte, gas, gasPrice, value *big.Int) (ret []byte, addr common.Address, err error) {
 	evm := vm.NewVm(env)
-
 	// Depth check execution. Fail if we're trying to execute above the
 	// limit.
 	if env.Depth() > int(params.CallCreateDepth.Int64()) {
@@ -72,13 +81,11 @@ func exec(env vm.Environment, caller vm.ContractRef, address, codeAddr *common.A
 		// Generate a new address
 		nonce := env.Db().GetNonce(caller.Address())
 		env.Db().SetNonce(caller.Address(), nonce+1)
-
 		addr = crypto.CreateAddress(caller.Address(), nonce)
-
 		address = &addr
 		createAccount = true
 	}
-	snapshot := env.MakeSnapshot()
+	snapshotPreTransfer := env.MakeSnapshot()
 
 	var (
 		from = env.Db().GetAccount(caller.Address())
@@ -94,15 +101,62 @@ func exec(env vm.Environment, caller vm.ContractRef, address, codeAddr *common.A
 		}
 	}
 	env.Transfer(from, to, value)
+	snapshotPostTransfer := env.MakeSnapshot()
 
 	contract := vm.NewContract(caller, to, value, gas, gasPrice)
 	contract.SetCallCode(codeAddr, code)
 
 	ret, err = evm.Run(contract, input)
+
 	if err != nil {
-		env.SetSnapshot(snapshot) //env.Db().Set(snapshot)
+		if err == vm.CodeStoreOutOfGasError {
+			// TODO: this is rather hacky, restore all state changes
+			// except sender's account nonce increment
+			toNonce := env.Db().GetNonce(to.Address())
+			env.SetSnapshot(snapshotPostTransfer)
+			env.Db().SetNonce(to.Address(), toNonce)
+		} else {
+			env.SetSnapshot(snapshotPreTransfer) //env.Db().Set(snapshot)
+		}
+	}
+	return ret, addr, err
+}
+
+func execDelegateCall(env vm.Environment, caller vm.ContractRef, originAddr, toAddr, codeAddr *common.Address, input, code []byte, gas, gasPrice, value *big.Int) (ret []byte, addr common.Address, err error) {
+	evm := vm.NewVm(env)
+	// Depth check execution. Fail if we're trying to execute above the
+	// limit.
+	if env.Depth() > int(params.CallCreateDepth.Int64()) {
+		caller.ReturnGas(gas, gasPrice)
+		return nil, common.Address{}, vm.DepthError
+	}
+
+	if !env.CanTransfer(*originAddr, value) {
+		caller.ReturnGas(gas, gasPrice)
+		return nil, common.Address{}, ValueTransferErr("insufficient funds to transfer value. Req %v, has %v", value, env.Db().GetBalance(caller.Address()))
+	}
+
+	snapshot := env.MakeSnapshot()
+
+	var (
+		//from = env.Db().GetAccount(*originAddr)
+		to vm.Account
+	)
+	if !env.Db().Exist(*toAddr) {
+		to = env.Db().CreateAccount(*toAddr)
+	} else {
+		to = env.Db().GetAccount(*toAddr)
 	}
 
+	contract := vm.NewContract(caller, to, value, gas, gasPrice)
+	contract.SetCallCode(codeAddr, code)
+	contract.DelegateCall = true
+
+	ret, err = evm.Run(contract, input)
+
+	if err != nil {
+		env.SetSnapshot(snapshot) //env.Db().Set(snapshot)
+	}
 	return ret, addr, err
 }