neo-go/pkg/core/native/notary.go
2020-11-25 18:37:29 +03:00

357 lines
12 KiB
Go

package native
import (
"errors"
"fmt"
"math"
"math/big"
"github.com/nspcc-dev/neo-go/pkg/core/dao"
"github.com/nspcc-dev/neo-go/pkg/core/interop"
"github.com/nspcc-dev/neo-go/pkg/core/interop/contract"
"github.com/nspcc-dev/neo-go/pkg/core/interop/runtime"
"github.com/nspcc-dev/neo-go/pkg/core/state"
"github.com/nspcc-dev/neo-go/pkg/core/storage"
"github.com/nspcc-dev/neo-go/pkg/core/transaction"
"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
"github.com/nspcc-dev/neo-go/pkg/smartcontract"
"github.com/nspcc-dev/neo-go/pkg/smartcontract/manifest"
"github.com/nspcc-dev/neo-go/pkg/util"
"github.com/nspcc-dev/neo-go/pkg/vm"
"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
)
// Notary represents Notary native contract.
type Notary struct {
interop.ContractMD
GAS *GAS
Desig *Designate
}
const (
notaryName = "Notary"
notaryContractID = reservedContractID - 1
// prefixDeposit is a prefix for storing Notary deposits.
prefixDeposit = 1
)
// newNotary returns Notary native contract.
func newNotary() *Notary {
n := &Notary{ContractMD: *interop.NewContractMD(notaryName)}
n.ContractID = notaryContractID
desc := newDescriptor("onPayment", smartcontract.VoidType,
manifest.NewParameter("from", smartcontract.Hash160Type),
manifest.NewParameter("amount", smartcontract.IntegerType),
manifest.NewParameter("data", smartcontract.AnyType))
md := newMethodAndPrice(n.onPayment, 100_0000, smartcontract.AllowModifyStates)
n.AddMethod(md, desc, true)
desc = newDescriptor("lockDepositUntil", smartcontract.BoolType,
manifest.NewParameter("address", smartcontract.Hash160Type),
manifest.NewParameter("till", smartcontract.IntegerType))
md = newMethodAndPrice(n.lockDepositUntil, 100_0000, smartcontract.AllowModifyStates)
n.AddMethod(md, desc, true)
desc = newDescriptor("withdraw", smartcontract.BoolType,
manifest.NewParameter("from", smartcontract.Hash160Type),
manifest.NewParameter("to", smartcontract.Hash160Type))
md = newMethodAndPrice(n.withdraw, 100_0000, smartcontract.AllowModifyStates)
n.AddMethod(md, desc, true)
desc = newDescriptor("balanceOf", smartcontract.IntegerType,
manifest.NewParameter("addr", smartcontract.Hash160Type))
md = newMethodAndPrice(n.balanceOf, 100_0000, smartcontract.AllowStates)
n.AddMethod(md, desc, true)
desc = newDescriptor("expirationOf", smartcontract.IntegerType,
manifest.NewParameter("addr", smartcontract.Hash160Type))
md = newMethodAndPrice(n.expirationOf, 100_0000, smartcontract.AllowStates)
n.AddMethod(md, desc, true)
desc = newDescriptor("verify", smartcontract.BoolType,
manifest.NewParameter("signature", smartcontract.SignatureType))
md = newMethodAndPrice(n.verify, 100_0000, smartcontract.AllowStates)
n.AddMethod(md, desc, false)
desc = newDescriptor("onPersist", smartcontract.VoidType)
md = newMethodAndPrice(getOnPersistWrapper(n.OnPersist), 0, smartcontract.AllowModifyStates)
n.AddMethod(md, desc, false)
desc = newDescriptor("postPersist", smartcontract.VoidType)
md = newMethodAndPrice(getOnPersistWrapper(postPersistBase), 0, smartcontract.AllowModifyStates)
n.AddMethod(md, desc, false)
return n
}
// Metadata implements Contract interface.
func (n *Notary) Metadata() *interop.ContractMD {
return &n.ContractMD
}
// Initialize initializes Notary native contract and implements Contract interface.
func (n *Notary) Initialize(ic *interop.Context) error {
return nil
}
// OnPersist implements Contract interface.
func (n *Notary) OnPersist(ic *interop.Context) error {
var (
nFees int64
notaries keys.PublicKeys
err error
)
for _, tx := range ic.Block.Transactions {
if tx.HasAttribute(transaction.NotaryAssistedT) {
if notaries == nil {
notaries, err = n.GetNotaryNodes(ic.DAO)
if err != nil {
return fmt.Errorf("failed to get notary nodes: %w", err)
}
}
nKeys := tx.GetAttributes(transaction.NotaryAssistedT)[0].Value.(*transaction.NotaryAssisted).NKeys
nFees += int64(nKeys) + 1
if tx.Sender() == n.Hash {
payer := tx.Signers[1]
balance := n.getDepositFor(ic.DAO, payer.Account)
balance.Amount.Sub(balance.Amount, big.NewInt(tx.SystemFee+tx.NetworkFee))
if balance.Amount.Sign() == 0 {
err := n.removeDepositFor(ic.DAO, payer.Account)
if err != nil {
return fmt.Errorf("failed to remove an empty deposit for %s from storage: %w", payer.Account.StringBE(), err)
}
} else {
err := n.putDepositFor(ic.DAO, balance, payer.Account)
if err != nil {
return fmt.Errorf("failed to update deposit for %s: %w", payer.Account.StringBE(), err)
}
}
}
}
}
if nFees == 0 {
return nil
}
singleReward := calculateNotaryReward(nFees, len(notaries))
for _, notary := range notaries {
n.GAS.mint(ic, notary.GetScriptHash(), singleReward)
}
return nil
}
// onPayment records deposited amount as belonging to "from" address with a lock
// till the specified chain's height.
func (n *Notary) onPayment(ic *interop.Context, args []stackitem.Item) stackitem.Item {
if h := ic.VM.GetCallingScriptHash(); h != n.GAS.Hash {
panic(fmt.Errorf("only GAS can be accepted for deposit, got %s", h.StringBE()))
}
from := toUint160(args[0])
to := from
amount := toBigInt(args[1])
data, ok := args[2].(*stackitem.Array)
if !ok || len(data.Value().([]stackitem.Item)) != 2 {
panic(errors.New("`data` parameter should be an array of 2 elements"))
}
additionalParams := data.Value().([]stackitem.Item)
if !additionalParams[0].Equals(stackitem.Null{}) {
to = toUint160(additionalParams[0])
}
till := toUint32(additionalParams[1])
currentHeight := ic.Chain.BlockHeight()
if till < currentHeight {
panic(fmt.Errorf("`till` shouldn't be less then the chain's height %d", currentHeight))
}
deposit := n.getDepositFor(ic.DAO, to)
if deposit == nil {
if amount.Cmp(big.NewInt(2*transaction.NotaryServiceFeePerKey)) < 0 {
panic(fmt.Errorf("first deposit can not be less then %d, got %d", 2*transaction.NotaryServiceFeePerKey, amount.Int64()))
}
deposit = &state.Deposit{
Amount: new(big.Int),
}
} else {
if till < deposit.Till {
panic(fmt.Errorf("`till` shouldn't be less then the previous value %d", deposit.Till))
}
}
deposit.Amount.Add(deposit.Amount, amount)
deposit.Till = till
if err := n.putDepositFor(ic.DAO, deposit, to); err != nil {
panic(fmt.Errorf("failed to put deposit for %s into the storage: %w", from.StringBE(), err))
}
return stackitem.Null{}
}
// lockDepositUntil updates the chain's height until which deposit is locked.
func (n *Notary) lockDepositUntil(ic *interop.Context, args []stackitem.Item) stackitem.Item {
addr := toUint160(args[0])
ok, err := runtime.CheckHashedWitness(ic, addr)
if err != nil {
panic(fmt.Errorf("failed to check witness for %s: %w", addr.StringBE(), err))
}
if !ok {
return stackitem.NewBool(false)
}
till := toUint32(args[1])
if till < ic.Chain.BlockHeight() {
return stackitem.NewBool(false)
}
deposit := n.getDepositFor(ic.DAO, addr)
if deposit == nil {
return stackitem.NewBool(false)
}
if till < deposit.Till {
return stackitem.NewBool(false)
}
deposit.Till = till
err = n.putDepositFor(ic.DAO, deposit, addr)
if err != nil {
panic(fmt.Errorf("failed to put deposit for %s into the storage: %w", addr.StringBE(), err))
}
return stackitem.NewBool(true)
}
// withdraw sends all deposited GAS for "from" address to "to" address.
func (n *Notary) withdraw(ic *interop.Context, args []stackitem.Item) stackitem.Item {
from := toUint160(args[0])
ok, err := runtime.CheckHashedWitness(ic, from)
if err != nil {
panic(fmt.Errorf("failed to check witness for %s: %w", from.StringBE(), err))
}
if !ok {
return stackitem.NewBool(false)
}
to := from
if !args[1].Equals(stackitem.Null{}) {
to = toUint160(args[1])
}
deposit := n.getDepositFor(ic.DAO, from)
if deposit == nil {
return stackitem.NewBool(false)
}
if ic.Chain.BlockHeight() < deposit.Till {
return stackitem.NewBool(false)
}
cs, err := ic.DAO.GetContractState(n.GAS.Hash)
if err != nil {
panic(fmt.Errorf("failed to get GAS contract state: %w", err))
}
transferArgs := []stackitem.Item{stackitem.NewByteArray(n.Hash.BytesBE()), stackitem.NewByteArray(to.BytesBE()), stackitem.NewBigInteger(deposit.Amount), stackitem.Null{}}
err = contract.CallExInternal(ic, cs, "transfer", transferArgs, smartcontract.All, vm.EnsureIsEmpty, func(ctx *vm.Context) { // we need EnsureIsEmpty because there's a callback popping result from the stack
isTransferOk := ic.VM.Estack().Pop().Bool()
if !isTransferOk {
panic("failed to transfer GAS from Notary account")
}
})
if err != nil {
panic(fmt.Errorf("failed to transfer GAS from Notary account: %w", err))
}
if err := n.removeDepositFor(ic.DAO, from); err != nil {
panic(fmt.Errorf("failed to remove withdrawn deposit for %s from the storage: %w", from.StringBE(), err))
}
return stackitem.NewBool(true)
}
// balanceOf returns deposited GAS amount for specified address.
func (n *Notary) balanceOf(ic *interop.Context, args []stackitem.Item) stackitem.Item {
acc := toUint160(args[0])
deposit := n.getDepositFor(ic.DAO, acc)
if deposit == nil {
return stackitem.NewBigInteger(big.NewInt(0))
}
return stackitem.NewBigInteger(deposit.Amount)
}
// expirationOf Returns deposit lock height for specified address.
func (n *Notary) expirationOf(ic *interop.Context, args []stackitem.Item) stackitem.Item {
acc := toUint160(args[0])
deposit := n.getDepositFor(ic.DAO, acc)
if deposit == nil {
return stackitem.Make(0)
}
return stackitem.Make(deposit.Till)
}
// verify checks whether the transaction was signed by one of the notaries.
func (n *Notary) verify(ic *interop.Context, args []stackitem.Item) stackitem.Item {
sig, err := args[0].TryBytes()
if err != nil {
panic(fmt.Errorf("failed to get signature bytes: %w", err))
}
tx := ic.Tx
if len(tx.GetAttributes(transaction.NotaryAssistedT)) == 0 {
return stackitem.NewBool(false)
}
for _, signer := range tx.Signers {
if signer.Account == n.Hash {
if signer.Scopes != transaction.None {
return stackitem.NewBool(false)
}
}
}
if tx.Sender() == n.Hash {
if len(tx.Signers) != 2 {
return stackitem.NewBool(false)
}
payer := tx.Signers[1].Account
balance := n.getDepositFor(ic.DAO, payer)
if balance == nil || balance.Amount.Cmp(big.NewInt(tx.NetworkFee+tx.SystemFee)) < 0 {
return stackitem.NewBool(false)
}
}
notaries, err := n.GetNotaryNodes(ic.DAO)
if err != nil {
panic(fmt.Errorf("failed to get notary nodes: %w", err))
}
hash := tx.GetSignedHash().BytesBE()
var verified bool
for _, n := range notaries {
if n.Verify(sig, hash) {
verified = true
break
}
}
return stackitem.NewBool(verified)
}
// GetNotaryNodes returns public keys of notary nodes.
func (n *Notary) GetNotaryNodes(d dao.DAO) (keys.PublicKeys, error) {
nodes, _, err := n.Desig.GetDesignatedByRole(d, RoleP2PNotary, math.MaxUint32)
return nodes, err
}
// getDepositFor returns state.Deposit for the account specified. It returns nil in case if
// deposit is not found in storage and panics in case of any other error.
func (n *Notary) getDepositFor(dao dao.DAO, acc util.Uint160) *state.Deposit {
key := append([]byte{prefixDeposit}, acc.BytesBE()...)
deposit := new(state.Deposit)
err := getSerializableFromDAO(n.ContractID, dao, key, deposit)
if err == nil {
return deposit
}
if err == storage.ErrKeyNotFound {
return nil
}
panic(fmt.Errorf("failed to get deposit for %s from storage: %w", acc.StringBE(), err))
}
// putDepositFor puts deposit on the balance of the specified account in the storage.
func (n *Notary) putDepositFor(dao dao.DAO, deposit *state.Deposit, acc util.Uint160) error {
key := append([]byte{prefixDeposit}, acc.BytesBE()...)
return putSerializableToDAO(n.ContractID, dao, key, deposit)
}
// removeDepositFor removes deposit from the storage.
func (n *Notary) removeDepositFor(dao dao.DAO, acc util.Uint160) error {
key := append([]byte{prefixDeposit}, acc.BytesBE()...)
return dao.DeleteStorageItem(n.ContractID, key)
}
// calculateNotaryReward calculates the reward for a single notary node based on FEE's count and Notary nodes count.
func calculateNotaryReward(nFees int64, notariesCount int) *big.Int {
return big.NewInt(nFees * transaction.NotaryServiceFeePerKey / int64(notariesCount))
}