The core protocol of WoopChain
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woop/core/state_transition.go

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14 KiB

// Copyright 2014 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package core
import (
"math"
"math/big"
staking2 "github.com/harmony-one/harmony/staking"
"github.com/harmony-one/harmony/staking/network"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/rlp"
"github.com/harmony-one/harmony/core/types"
"github.com/harmony-one/harmony/core/vm"
"github.com/harmony-one/harmony/internal/params"
"github.com/harmony-one/harmony/internal/utils"
staking "github.com/harmony-one/harmony/staking/types"
"github.com/pkg/errors"
)
var (
errInvalidSigner = errors.New("invalid signer for staking transaction")
errInsufficientBalanceForGas = errors.New("insufficient balance to pay for gas")
errInsufficientBalanceForStake = errors.New("insufficient balance to stake")
errValidatorExist = errors.New("staking validator already exists")
errValidatorNotExist = errors.New("staking validator does not exist")
errNoDelegationToUndelegate = errors.New("no delegation to undelegate")
errCommissionRateChangeTooFast = errors.New("change on commission rate can not be more than max change rate within the same epoch")
errCommissionRateChangeTooHigh = errors.New("commission rate can not be higher than maximum commission rate")
errNoRewardsToCollect = errors.New("no rewards to collect")
errNegativeAmount = errors.New("amount can not be negative")
)
/*
StateTransition is the State Transitioning Model which is described as follows:
A state transition is a change made when a transaction is applied to the current world state
The state transitioning model does all the necessary work to work out a valid new state root.
1) Nonce handling
2) Pre pay gas
3) Create a new state object if the recipient is \0*32
4) Value transfer
== If contract creation ==
4a) Attempt to run transaction data
4b) If valid, use result as code for the new state object
== end ==
5) Run Script section
6) Derive new state root
*/
type StateTransition struct {
gp *GasPool
msg Message
gas uint64
gasPrice *big.Int
initialGas uint64
value *big.Int
data []byte
state vm.StateDB
evm *vm.EVM
bc ChainContext
}
// Message represents a message sent to a contract.
type Message interface {
From() common.Address
//FromFrontier() (common.Address, error)
To() *common.Address
GasPrice() *big.Int
Gas() uint64
Value() *big.Int
Nonce() uint64
CheckNonce() bool
Data() []byte
Type() types.TransactionType
BlockNum() *big.Int
}
// IntrinsicGas computes the 'intrinsic gas' for a message with the given data.
func IntrinsicGas(data []byte, contractCreation, homestead, isValidatorCreation bool) (uint64, error) {
// Set the starting gas for the raw transaction
var gas uint64
if contractCreation && homestead {
gas = params.TxGasContractCreation
} else if isValidatorCreation {
gas = params.TxGasValidatorCreation
} else {
gas = params.TxGas
}
// Bump the required gas by the amount of transactional data
if len(data) > 0 {
// Zero and non-zero bytes are priced differently
var nz uint64
for _, byt := range data {
if byt != 0 {
nz++
}
}
// Make sure we don't exceed uint64 for all data combinations
if (math.MaxUint64-gas)/params.TxDataNonZeroGas < nz {
return 0, vm.ErrOutOfGas
}
gas += nz * params.TxDataNonZeroGas
z := uint64(len(data)) - nz
if (math.MaxUint64-gas)/params.TxDataZeroGas < z {
return 0, vm.ErrOutOfGas
}
gas += z * params.TxDataZeroGas
}
return gas, nil
}
// NewStateTransition initialises and returns a new state transition object.
func NewStateTransition(evm *vm.EVM, msg Message, gp *GasPool, bc ChainContext) *StateTransition {
return &StateTransition{
gp: gp,
evm: evm,
msg: msg,
gasPrice: msg.GasPrice(),
value: msg.Value(),
data: msg.Data(),
state: evm.StateDB,
bc: bc,
}
}
// ApplyMessage computes the new state by applying the given message
// against the old state within the environment.
//
// ApplyMessage returns the bytes returned by any EVM execution (if it took place),
// the gas used (which includes gas refunds) and an error if it failed. An error always
// indicates a core error meaning that the message would always fail for that particular
// state and would never be accepted within a block.
func ApplyMessage(evm *vm.EVM, msg Message, gp *GasPool) ([]byte, uint64, bool, error) {
return NewStateTransition(evm, msg, gp, nil).TransitionDb()
}
// ApplyStakingMessage computes the new state for staking message
func ApplyStakingMessage(evm *vm.EVM, msg Message, gp *GasPool, bc ChainContext) (uint64, error) {
return NewStateTransition(evm, msg, gp, bc).StakingTransitionDb()
}
// to returns the recipient of the message.
func (st *StateTransition) to() common.Address {
if st.msg == nil || st.msg.To() == nil /* contract creation */ {
return common.Address{}
}
return *st.msg.To()
}
func (st *StateTransition) useGas(amount uint64) error {
if st.gas < amount {
return vm.ErrOutOfGas
}
st.gas -= amount
return nil
}
func (st *StateTransition) buyGas() error {
mgval := new(big.Int).Mul(new(big.Int).SetUint64(st.msg.Gas()), st.gasPrice)
if have := st.state.GetBalance(st.msg.From()); have.Cmp(mgval) < 0 {
return errors.Wrapf(
errInsufficientBalanceForGas,
"had: %s but need: %s", have.String(), mgval.String(),
)
}
if err := st.gp.SubGas(st.msg.Gas()); err != nil {
return err
}
st.gas += st.msg.Gas()
st.initialGas = st.msg.Gas()
st.state.SubBalance(st.msg.From(), mgval)
return nil
}
func (st *StateTransition) preCheck() error {
// Make sure this transaction's nonce is correct.
if st.msg.CheckNonce() {
nonce := st.state.GetNonce(st.msg.From())
if nonce < st.msg.Nonce() {
return ErrNonceTooHigh
} else if nonce > st.msg.Nonce() {
return ErrNonceTooLow
}
}
return st.buyGas()
}
// TransitionDb will transition the state by applying the current message and
// returning the result including the used gas. It returns an error if failed.
// An error indicates a consensus issue.
func (st *StateTransition) TransitionDb() (ret []byte, usedGas uint64, failed bool, err error) {
if err = st.preCheck(); err != nil {
return
}
msg := st.msg
sender := vm.AccountRef(msg.From())
homestead := st.evm.ChainConfig().IsS3(st.evm.EpochNumber) // s3 includes homestead
contractCreation := msg.To() == nil
// Pay intrinsic gas
gas, err := IntrinsicGas(st.data, contractCreation, homestead, false)
if err != nil {
return nil, 0, false, err
}
if err = st.useGas(gas); err != nil {
return nil, 0, false, err
}
var (
evm = st.evm
// vm errors do not effect consensus and are therefor
// not assigned to err, except for insufficient balance
// error.
vmerr error
)
if contractCreation {
ret, _, st.gas, vmerr = evm.Create(sender, st.data, st.gas, st.value)
} else {
// Increment the nonce for the next transaction
st.state.SetNonce(msg.From(), st.state.GetNonce(sender.Address())+1)
ret, st.gas, vmerr = evm.Call(sender, st.to(), st.data, st.gas, st.value)
}
if vmerr != nil {
utils.Logger().Debug().Err(vmerr).Msg("VM returned with error")
// The only possible consensus-error would be if there wasn't
// sufficient balance to make the transfer happen. The first
// balance transfer may never fail.
if vmerr == vm.ErrInsufficientBalance {
return nil, 0, false, vmerr
}
}
st.refundGas()
txFee := new(big.Int).Mul(new(big.Int).SetUint64(st.gasUsed()), st.gasPrice)
st.state.AddBalance(st.evm.Coinbase, txFee)
return ret, st.gasUsed(), vmerr != nil, err
}
func (st *StateTransition) refundGas() {
// Apply refund counter, capped to half of the used gas.
refund := st.gasUsed() / 2
if refund > st.state.GetRefund() {
refund = st.state.GetRefund()
}
st.gas += refund
// Return ETH for remaining gas, exchanged at the original rate.
remaining := new(big.Int).Mul(new(big.Int).SetUint64(st.gas), st.gasPrice)
st.state.AddBalance(st.msg.From(), remaining)
// Also return remaining gas to the block gas counter so it is
// available for the next transaction.
st.gp.AddGas(st.gas)
}
// gasUsed returns the amount of gas used up by the state transition.
func (st *StateTransition) gasUsed() uint64 {
return st.initialGas - st.gas
}
// StakingTransitionDb will transition the state by applying the staking message and
// returning the result including the used gas. It returns an error if failed.
// It is used for staking transaction only
func (st *StateTransition) StakingTransitionDb() (usedGas uint64, err error) {
if err = st.preCheck(); err != nil {
return 0, err
}
msg := st.msg
sender := vm.AccountRef(msg.From())
homestead := st.evm.ChainConfig().IsS3(st.evm.EpochNumber) // s3 includes homestead
// Pay intrinsic gas
gas, err := IntrinsicGas(st.data, false, homestead, msg.Type() == types.StakeCreateVal)
if err != nil {
return 0, err
}
if err = st.useGas(gas); err != nil {
return 0, err
}
// Increment the nonce for the next transaction
st.state.SetNonce(msg.From(), st.state.GetNonce(sender.Address())+1)
switch msg.Type() {
case types.StakeCreateVal:
stkMsg := &staking.CreateValidator{}
if err = rlp.DecodeBytes(msg.Data(), stkMsg); err != nil {
return 0, err
}
utils.Logger().Info().Msgf("[DEBUG STAKING] staking type: %s, gas: %d, txn: %+v", msg.Type(), gas, stkMsg)
if msg.From() != stkMsg.ValidatorAddress {
return 0, errInvalidSigner
}
err = st.verifyAndApplyCreateValidatorTx(stkMsg, msg.BlockNum())
case types.StakeEditVal:
stkMsg := &staking.EditValidator{}
if err = rlp.DecodeBytes(msg.Data(), stkMsg); err != nil {
return 0, err
}
utils.Logger().Info().Msgf("[DEBUG STAKING] staking type: %s, gas: %d, txn: %+v", msg.Type(), gas, stkMsg)
if msg.From() != stkMsg.ValidatorAddress {
return 0, errInvalidSigner
}
err = st.verifyAndApplyEditValidatorTx(stkMsg, msg.BlockNum())
case types.Delegate:
stkMsg := &staking.Delegate{}
if err = rlp.DecodeBytes(msg.Data(), stkMsg); err != nil {
return 0, err
}
utils.Logger().Info().Msgf("[DEBUG STAKING] staking type: %s, gas: %d, txn: %+v", msg.Type(), gas, stkMsg)
if msg.From() != stkMsg.DelegatorAddress {
return 0, errInvalidSigner
}
err = st.verifyAndApplyDelegateTx(stkMsg)
case types.Undelegate:
stkMsg := &staking.Undelegate{}
if err = rlp.DecodeBytes(msg.Data(), stkMsg); err != nil {
return 0, err
}
utils.Logger().Info().Msgf("[DEBUG STAKING] staking type: %s, gas: %d, txn: %+v", msg.Type(), gas, stkMsg)
if msg.From() != stkMsg.DelegatorAddress {
return 0, errInvalidSigner
}
err = st.verifyAndApplyUndelegateTx(stkMsg)
case types.CollectRewards:
stkMsg := &staking.CollectRewards{}
if err = rlp.DecodeBytes(msg.Data(), stkMsg); err != nil {
return 0, err
}
utils.Logger().Info().Msgf("[DEBUG STAKING] staking type: %s, gas: %d, txn: %+v", msg.Type(), gas, stkMsg)
if msg.From() != stkMsg.DelegatorAddress {
return 0, errInvalidSigner
}
collectedRewards, err := st.verifyAndApplyCollectRewards(stkMsg)
if err == nil {
st.state.AddLog(&types.Log{
Address: stkMsg.DelegatorAddress,
Topics: []common.Hash{staking2.CollectRewardsTopic},
Data: collectedRewards.Bytes(),
BlockNumber: st.evm.BlockNumber.Uint64(),
})
}
default:
return 0, staking.ErrInvalidStakingKind
}
st.refundGas()
txFee := new(big.Int).Mul(new(big.Int).SetUint64(st.gasUsed()), st.gasPrice)
st.state.AddBalance(st.evm.Coinbase, txFee)
return st.gasUsed(), err
}
func (st *StateTransition) verifyAndApplyCreateValidatorTx(
createValidator *staking.CreateValidator, blockNum *big.Int,
) error {
wrapper, err := VerifyAndCreateValidatorFromMsg(st.state, st.evm.EpochNumber, blockNum, createValidator)
if err != nil {
return err
}
if err := st.state.UpdateValidatorWrapper(wrapper.Address, wrapper); err != nil {
return err
}
st.state.SetValidatorFlag(wrapper.Address)
st.state.SubBalance(wrapper.Address, createValidator.Amount)
return nil
}
func (st *StateTransition) verifyAndApplyEditValidatorTx(
editValidator *staking.EditValidator, blockNum *big.Int,
) error {
wrapper, err := VerifyAndEditValidatorFromMsg(st.state, st.bc, blockNum, editValidator)
if err != nil {
return err
}
return st.state.UpdateValidatorWrapper(wrapper.Address, wrapper)
}
func (st *StateTransition) verifyAndApplyDelegateTx(delegate *staking.Delegate) error {
wrapper, balanceToBeDeducted, err := VerifyAndDelegateFromMsg(st.state, delegate)
if err != nil {
return err
}
st.state.SubBalance(delegate.DelegatorAddress, balanceToBeDeducted)
return st.state.UpdateValidatorWrapper(wrapper.Address, wrapper)
}
func (st *StateTransition) verifyAndApplyUndelegateTx(undelegate *staking.Undelegate) error {
wrapper, err := VerifyAndUndelegateFromMsg(st.state, st.evm.EpochNumber, undelegate)
if err != nil {
return err
}
return st.state.UpdateValidatorWrapper(wrapper.Address, wrapper)
}
func (st *StateTransition) verifyAndApplyCollectRewards(collectRewards *staking.CollectRewards) (*big.Int, error) {
if st.bc == nil {
return network.NoReward, errors.New("[CollectRewards] No chain context provided")
}
// TODO(audit): make sure the delegation index is always consistent with onchain data
delegations, err := st.bc.ReadDelegationsByDelegator(collectRewards.DelegatorAddress)
if err != nil {
return network.NoReward, err
}
updatedValidatorWrappers, totalRewards, err := VerifyAndCollectRewardsFromDelegation(
st.state, delegations,
)
if err != nil {
return network.NoReward, err
}
for _, wrapper := range updatedValidatorWrappers {
if err := st.state.UpdateValidatorWrapper(wrapper.Address, wrapper); err != nil {
return network.NoReward, err
}
}
st.state.AddBalance(collectRewards.DelegatorAddress, totalRewards)
return totalRewards, nil
}