native: implement delegated voting

Close #867.
This commit is contained in:
Evgenii Stratonikov 2020-08-03 15:00:27 +03:00
parent f0b62cdaa6
commit 9bc731b3b1
8 changed files with 223 additions and 181 deletions

View file

@ -7,6 +7,7 @@ ProtocolConfiguration:
- 02103a7f7dd016558597f7960d27c516a4394fd968b9e65155eb4b013e4040406e - 02103a7f7dd016558597f7960d27c516a4394fd968b9e65155eb4b013e4040406e
- 03d90c07df63e690ce77912e10ab51acc944b66860237b608c4f8f8309e71ee699 - 03d90c07df63e690ce77912e10ab51acc944b66860237b608c4f8f8309e71ee699
- 02a7bc55fe8684e0119768d104ba30795bdcc86619e864add26156723ed185cd62 - 02a7bc55fe8684e0119768d104ba30795bdcc86619e864add26156723ed185cd62
ValidatorsCount: 4
SeedList: SeedList:
- 127.0.0.1:20334 - 127.0.0.1:20334
- 127.0.0.1:20335 - 127.0.0.1:20335

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@ -14,6 +14,7 @@ type (
SecondsPerBlock int `yaml:"SecondsPerBlock"` SecondsPerBlock int `yaml:"SecondsPerBlock"`
SeedList []string `yaml:"SeedList"` SeedList []string `yaml:"SeedList"`
StandbyValidators []string `yaml:"StandbyValidators"` StandbyValidators []string `yaml:"StandbyValidators"`
ValidatorsCount int `yaml:"ValidatorsCount"`
// Whether to verify received blocks. // Whether to verify received blocks.
VerifyBlocks bool `yaml:"VerifyBlocks"` VerifyBlocks bool `yaml:"VerifyBlocks"`
// Whether to verify transactions in received blocks. // Whether to verify transactions in received blocks.

View file

@ -44,12 +44,14 @@ const (
NEOTotalSupply = 100000000 NEOTotalSupply = 100000000
// prefixCandidate is a prefix used to store validator's data. // prefixCandidate is a prefix used to store validator's data.
prefixCandidate = 33 prefixCandidate = 33
// prefixVotersCount is a prefix for storing total amount of NEO of voters.
prefixVotersCount = 1
// effectiveVoterTurnout represents minimal ratio of total supply to total amount voted value
// which is require to use non-standby validators.
effectiveVoterTurnout = 5
) )
var ( var (
// validatorsCountKey is a key used to store validators count
// used to determine the real number of validators.
validatorsCountKey = []byte{15}
// nextValidatorsKey is a key used to store validators for the // nextValidatorsKey is a key used to store validators for the
// next block. // next block.
nextValidatorsKey = []byte{14} nextValidatorsKey = []byte{14}
@ -96,7 +98,7 @@ func NewNEO() *NEO {
desc = newDescriptor("vote", smartcontract.BoolType, desc = newDescriptor("vote", smartcontract.BoolType,
manifest.NewParameter("account", smartcontract.Hash160Type), manifest.NewParameter("account", smartcontract.Hash160Type),
manifest.NewParameter("pubkeys", smartcontract.ArrayType)) manifest.NewParameter("pubkey", smartcontract.PublicKeyType))
md = newMethodAndPrice(n.vote, 500000000, smartcontract.AllowModifyStates) md = newMethodAndPrice(n.vote, 500000000, smartcontract.AllowModifyStates)
n.AddMethod(md, desc, false) n.AddMethod(md, desc, false)
@ -104,6 +106,10 @@ func NewNEO() *NEO {
md = newMethodAndPrice(n.getCandidatesCall, 100000000, smartcontract.AllowStates) md = newMethodAndPrice(n.getCandidatesCall, 100000000, smartcontract.AllowStates)
n.AddMethod(md, desc, true) n.AddMethod(md, desc, true)
desc = newDescriptor("getСommittee", smartcontract.ArrayType)
md = newMethodAndPrice(n.getCommittee, 100000000, smartcontract.AllowStates)
n.AddMethod(md, desc, true)
desc = newDescriptor("getValidators", smartcontract.ArrayType) desc = newDescriptor("getValidators", smartcontract.ArrayType)
md = newMethodAndPrice(n.getValidators, 100000000, smartcontract.AllowStates) md = newMethodAndPrice(n.getValidators, 100000000, smartcontract.AllowStates)
n.AddMethod(md, desc, true) n.AddMethod(md, desc, true)
@ -131,6 +137,11 @@ func (n *NEO) Initialize(ic *interop.Context) error {
} }
n.mint(ic, h, big.NewInt(NEOTotalSupply)) n.mint(ic, h, big.NewInt(NEOTotalSupply))
err = ic.DAO.PutStorageItem(n.ContractID, []byte{prefixVotersCount}, &state.StorageItem{Value: []byte{0}})
if err != nil {
return err
}
for i := range vs { for i := range vs {
if err := n.registerCandidateInternal(ic, vs[i]); err != nil { if err := n.registerCandidateInternal(ic, vs[i]); err != nil {
return err return err
@ -166,21 +177,11 @@ func (n *NEO) increaseBalance(ic *interop.Context, h util.Uint160, si *state.Sto
si.Value = acc.Bytes() si.Value = acc.Bytes()
return nil return nil
} }
if len(acc.Votes) > 0 { if err := n.ModifyAccountVotes(acc, ic.DAO, amount, modifyVoteTransfer); err != nil {
if err := n.ModifyAccountVotes(acc, ic.DAO, amount); err != nil {
return err return err
} }
siVC := ic.DAO.GetStorageItem(n.ContractID, validatorsCountKey) if acc.VoteTo != nil {
if siVC == nil { if err := n.modifyVoterTurnout(ic.DAO, amount); err != nil {
return errors.New("validators count uninitialized")
}
vc, err := ValidatorsCountFromBytes(siVC.Value)
if err != nil {
return err
}
vc[len(acc.Votes)-1].Add(&vc[len(acc.Votes)-1], amount)
siVC.Value = vc.Bytes()
if err := ic.DAO.PutStorageItem(n.ContractID, validatorsCountKey, siVC); err != nil {
return err return err
} }
} }
@ -224,35 +225,26 @@ func (n *NEO) registerCandidate(ic *interop.Context, args []stackitem.Item) stac
func (n *NEO) registerCandidateInternal(ic *interop.Context, pub *keys.PublicKey) error { func (n *NEO) registerCandidateInternal(ic *interop.Context, pub *keys.PublicKey) error {
key := makeValidatorKey(pub) key := makeValidatorKey(pub)
si := ic.DAO.GetStorageItem(n.ContractID, key) si := ic.DAO.GetStorageItem(n.ContractID, key)
if si != nil { if si == nil {
return errors.New("already registered")
}
si = new(state.StorageItem) si = new(state.StorageItem)
// Zero value. }
si.Value = []byte{} c := &candidate{Registered: true}
si.Value = c.Bytes()
return ic.DAO.PutStorageItem(n.ContractID, key, si) return ic.DAO.PutStorageItem(n.ContractID, key, si)
} }
func (n *NEO) vote(ic *interop.Context, args []stackitem.Item) stackitem.Item { func (n *NEO) vote(ic *interop.Context, args []stackitem.Item) stackitem.Item {
acc := toUint160(args[0]) acc := toUint160(args[0])
arr := args[1].Value().([]stackitem.Item) var pub *keys.PublicKey
var pubs keys.PublicKeys if _, ok := args[1].(stackitem.Null); !ok {
for i := range arr { pub = toPublicKey(args[1])
pub := new(keys.PublicKey)
bs, err := arr[i].TryBytes()
if err != nil {
panic(err)
} else if err := pub.DecodeBytes(bs); err != nil {
panic(err)
} }
pubs = append(pubs, pub) err := n.VoteInternal(ic, acc, pub)
}
err := n.VoteInternal(ic, acc, pubs)
return stackitem.NewBool(err == nil) return stackitem.NewBool(err == nil)
} }
// VoteInternal votes from account h for validarors specified in pubs. // VoteInternal votes from account h for validarors specified in pubs.
func (n *NEO) VoteInternal(ic *interop.Context, h util.Uint160, pubs keys.PublicKeys) error { func (n *NEO) VoteInternal(ic *interop.Context, h util.Uint160, pub *keys.PublicKey) error {
ok, err := runtime.CheckHashedWitness(ic, h) ok, err := runtime.CheckHashedWitness(ic, h)
if err != nil { if err != nil {
return err return err
@ -268,69 +260,57 @@ func (n *NEO) VoteInternal(ic *interop.Context, h util.Uint160, pubs keys.Public
if err != nil { if err != nil {
return err return err
} }
if err := n.ModifyAccountVotes(acc, ic.DAO, new(big.Int).Neg(&acc.Balance)); err != nil { if (acc.VoteTo == nil) != (pub == nil) {
return err val := &acc.Balance
if pub == nil {
val = new(big.Int).Neg(val)
} }
pubs = pubs.Unique() if err := n.modifyVoterTurnout(ic.DAO, val); err != nil {
// Check validators registration.
var newPubs keys.PublicKeys
for _, pub := range pubs {
if ic.DAO.GetStorageItem(n.ContractID, makeValidatorKey(pub)) == nil {
continue
}
newPubs = append(newPubs, pub)
}
if lp, lv := len(newPubs), len(acc.Votes); lp != lv {
var si *state.StorageItem
var vc *ValidatorsCount
var err error
si = ic.DAO.GetStorageItem(n.ContractID, validatorsCountKey)
if si == nil {
// The first voter.
si = new(state.StorageItem)
vc = new(ValidatorsCount)
} else {
vc, err = ValidatorsCountFromBytes(si.Value)
if err != nil {
return err return err
} }
} }
if lv > 0 { if err := n.ModifyAccountVotes(acc, ic.DAO, new(big.Int).Neg(&acc.Balance), modifyVoteOld); err != nil {
vc[lv-1].Sub(&vc[lv-1], &acc.Balance)
}
if len(newPubs) > 0 {
vc[lp-1].Add(&vc[lp-1], &acc.Balance)
}
si.Value = vc.Bytes()
if err := ic.DAO.PutStorageItem(n.ContractID, validatorsCountKey, si); err != nil {
return err return err
} }
} acc.VoteTo = pub
acc.Votes = newPubs if err := n.ModifyAccountVotes(acc, ic.DAO, &acc.Balance, modifyVoteNew); err != nil {
if err := n.ModifyAccountVotes(acc, ic.DAO, &acc.Balance); err != nil {
return err return err
} }
si.Value = acc.Bytes() si.Value = acc.Bytes()
return ic.DAO.PutStorageItem(n.ContractID, key, si) return ic.DAO.PutStorageItem(n.ContractID, key, si)
} }
const (
modifyVoteTransfer = iota
modifyVoteOld
modifyVoteNew
)
// ModifyAccountVotes modifies votes of the specified account by value (can be negative). // ModifyAccountVotes modifies votes of the specified account by value (can be negative).
func (n *NEO) ModifyAccountVotes(acc *state.NEOBalanceState, d dao.DAO, value *big.Int) error { // typ specifies if this modify is occuring during transfer or vote (with old or new validator).
for _, vote := range acc.Votes { func (n *NEO) ModifyAccountVotes(acc *state.NEOBalanceState, d dao.DAO, value *big.Int, typ int) error {
key := makeValidatorKey(vote) if acc.VoteTo != nil {
key := makeValidatorKey(acc.VoteTo)
si := d.GetStorageItem(n.ContractID, key) si := d.GetStorageItem(n.ContractID, key)
if si == nil { if si == nil {
return errors.New("invalid validator") return errors.New("invalid validator")
} }
votes := bigint.FromBytes(si.Value) cd := new(candidate).FromBytes(si.Value)
votes.Add(votes, value) cd.Votes.Add(&cd.Votes, value)
si.Value = bigint.ToPreallocatedBytes(votes, si.Value[:0]) switch typ {
if err := d.PutStorageItem(n.ContractID, key, si); err != nil { case modifyVoteOld:
return err if !cd.Registered && cd.Votes.Sign() == 0 {
return d.DeleteStorageItem(n.ContractID, key)
}
case modifyVoteNew:
if !cd.Registered {
return errors.New("validator must be registered")
} }
} }
n.validators.Store(keys.PublicKeys(nil)) n.validators.Store(keys.PublicKeys(nil))
si.Value = cd.Bytes()
return d.PutStorageItem(n.ContractID, key, si)
}
return nil return nil
} }
@ -341,8 +321,10 @@ func (n *NEO) getCandidates(d dao.DAO) ([]keyWithVotes, error) {
} }
arr := make([]keyWithVotes, 0, len(siMap)) arr := make([]keyWithVotes, 0, len(siMap))
for key, si := range siMap { for key, si := range siMap {
votes := bigint.FromBytes(si.Value) c := new(candidate).FromBytes(si.Value)
arr = append(arr, keyWithVotes{key, votes}) if c.Registered {
arr = append(arr, keyWithVotes{key, &c.Votes})
}
} }
sort.Slice(arr, func(i, j int) bool { return strings.Compare(arr[i].Key, arr[j].Key) == -1 }) sort.Slice(arr, func(i, j int) bool { return strings.Compare(arr[i].Key, arr[j].Key) == -1 })
return arr, nil return arr, nil
@ -386,53 +368,15 @@ func (n *NEO) GetValidatorsInternal(bc blockchainer.Blockchainer, d dao.DAO) (ke
if vals := n.validators.Load().(keys.PublicKeys); vals != nil { if vals := n.validators.Load().(keys.PublicKeys); vals != nil {
return vals.Copy(), nil return vals.Copy(), nil
} }
standByValidators := bc.GetStandByValidators() result, err := n.getCommitteeMembers(bc, d)
si := d.GetStorageItem(n.ContractID, validatorsCountKey)
if si == nil {
n.validators.Store(standByValidators)
return standByValidators.Copy(), nil
}
validatorsCount, err := ValidatorsCountFromBytes(si.Value)
if err != nil { if err != nil {
return nil, err return nil, err
} }
validators, err := n.GetCandidates(d) count := bc.GetConfig().ValidatorsCount
if err != nil { if len(result) < count {
return nil, err count = len(result)
} }
sort.Slice(validators, func(i, j int) bool {
// The most-voted validators should end up in the front of the list.
cmp := validators[i].Votes.Cmp(validators[j].Votes)
if cmp != 0 {
return cmp > 0
}
// Ties are broken with public keys.
return validators[i].Key.Cmp(validators[j].Key) == -1
})
count := validatorsCount.GetWeightedAverage()
if count < len(standByValidators) {
count = len(standByValidators)
}
uniqueSBValidators := standByValidators.Unique()
result := keys.PublicKeys{}
for _, validator := range validators {
if validator.Votes.Sign() > 0 || uniqueSBValidators.Contains(validator.Key) {
result = append(result, validator.Key)
}
}
if result.Len() >= count {
result = result[:count] result = result[:count]
} else {
for i := 0; i < uniqueSBValidators.Len() && result.Len() < count; i++ {
if !result.Contains(uniqueSBValidators[i]) {
result = append(result, uniqueSBValidators[i])
}
}
}
sort.Sort(result)
n.validators.Store(result) n.validators.Store(result)
return result, nil return result, nil
} }
@ -445,6 +389,68 @@ func (n *NEO) getValidators(ic *interop.Context, _ []stackitem.Item) stackitem.I
return pubsToArray(result) return pubsToArray(result)
} }
func (n *NEO) getCommittee(ic *interop.Context, _ []stackitem.Item) stackitem.Item {
pubs, err := n.getCommitteeMembers(ic.Chain, ic.DAO)
if err != nil {
panic(err)
}
sort.Sort(pubs)
return pubsToArray(pubs)
}
func (n *NEO) modifyVoterTurnout(d dao.DAO, amount *big.Int) error {
key := []byte{prefixVotersCount}
si := d.GetStorageItem(n.ContractID, key)
if si == nil {
return errors.New("voters count not found")
}
votersCount := bigint.FromBytes(si.Value)
votersCount.Add(votersCount, amount)
si.Value = bigint.ToBytes(votersCount)
return d.PutStorageItem(n.ContractID, key, si)
}
func (n *NEO) getCommitteeMembers(bc blockchainer.Blockchainer, d dao.DAO) (keys.PublicKeys, error) {
key := []byte{prefixVotersCount}
si := d.GetStorageItem(n.ContractID, key)
if si == nil {
return nil, errors.New("voters count not found")
}
votersCount := bigint.FromBytes(si.Value)
// votersCount / totalSupply must be >= 0.2
votersCount.Mul(votersCount, big.NewInt(effectiveVoterTurnout))
voterTurnout := votersCount.Div(votersCount, n.getTotalSupply(d))
if voterTurnout.Sign() != 1 {
return bc.GetStandByValidators(), nil
}
cs, err := n.getCandidates(d)
if err != nil {
return nil, err
}
sbVals := bc.GetStandByValidators()
count := len(sbVals)
if len(cs) < count {
return sbVals, nil
}
sort.Slice(cs, func(i, j int) bool {
// The most-voted validators should end up in the front of the list.
cmp := cs[i].Votes.Cmp(cs[j].Votes)
if cmp != 0 {
return cmp > 0
}
// Ties are broken with public keys.
return strings.Compare(cs[i].Key, cs[j].Key) == -1
})
pubs := make(keys.PublicKeys, count)
for i := range pubs {
pubs[i], err = keys.NewPublicKeyFromBytes([]byte(cs[i].Key), elliptic.P256())
if err != nil {
return nil, err
}
}
return pubs, nil
}
func (n *NEO) getNextBlockValidators(ic *interop.Context, _ []stackitem.Item) stackitem.Item { func (n *NEO) getNextBlockValidators(ic *interop.Context, _ []stackitem.Item) stackitem.Item {
result, err := n.getNextBlockValidatorsInternal(ic.Chain, ic.DAO) result, err := n.getNextBlockValidatorsInternal(ic.Chain, ic.DAO)
if err != nil { if err != nil {

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@ -0,0 +1,48 @@
package native
import (
"math/big"
"github.com/nspcc-dev/neo-go/pkg/io"
"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
)
type candidate struct {
Registered bool
Votes big.Int
}
// Bytes marshals c to byte array.
func (c *candidate) Bytes() []byte {
w := io.NewBufBinWriter()
stackitem.EncodeBinaryStackItem(c.toStackItem(), w.BinWriter)
return w.Bytes()
}
// FromBytes unmarshals candidate from byte array.
func (c *candidate) FromBytes(data []byte) *candidate {
r := io.NewBinReaderFromBuf(data)
item := stackitem.DecodeBinaryStackItem(r)
if r.Err != nil {
panic(r.Err)
}
return c.fromStackItem(item)
}
func (c *candidate) toStackItem() stackitem.Item {
return stackitem.NewStruct([]stackitem.Item{
stackitem.NewBool(c.Registered),
stackitem.NewBigInteger(&c.Votes),
})
}
func (c *candidate) fromStackItem(item stackitem.Item) *candidate {
arr := item.(*stackitem.Struct).Value().([]stackitem.Item)
vs, err := arr[1].TryInteger()
if err != nil {
panic(err)
}
c.Registered = arr[0].Bool()
c.Votes = *vs
return c
}

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@ -0,0 +1,18 @@
package native
import (
"math/big"
"testing"
"github.com/stretchr/testify/require"
)
func TestCandidate_Bytes(t *testing.T) {
expected := &candidate{
Registered: true,
Votes: *big.NewInt(0x0F),
}
data := expected.Bytes()
actual := new(candidate).FromBytes(data)
require.Equal(t, expected, actual)
}

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@ -63,51 +63,3 @@ func (vc *ValidatorsCount) DecodeBinary(r *io.BinReader) {
vc[i] = *bigint.FromBytes(buf) vc[i] = *bigint.FromBytes(buf)
} }
} }
// GetWeightedAverage returns an average count of validators that's been voted
// for not counting 1/4 of minimum and maximum numbers.
func (vc *ValidatorsCount) GetWeightedAverage() int {
const (
lowerThreshold = 0.25
upperThreshold = 0.75
)
var (
sumWeight, sumValue, overallSum, slidingSum int64
slidingRatio float64
)
for i := range vc {
overallSum += vc[i].Int64()
}
for i := range vc {
if slidingRatio >= upperThreshold {
break
}
weight := vc[i].Int64()
slidingSum += weight
previousRatio := slidingRatio
slidingRatio = float64(slidingSum) / float64(overallSum)
if slidingRatio <= lowerThreshold {
continue
}
if previousRatio < lowerThreshold {
if slidingRatio > upperThreshold {
weight = int64((upperThreshold - lowerThreshold) * float64(overallSum))
} else {
weight = int64((slidingRatio - lowerThreshold) * float64(overallSum))
}
} else if slidingRatio > upperThreshold {
weight = int64((upperThreshold - previousRatio) * float64(overallSum))
}
sumWeight += weight
// Votes with N values get stored with N-1 index, thus +1 here.
sumValue += (int64(i) + 1) * weight
}
if sumValue == 0 || sumWeight == 0 {
return 0
}
return int(sumValue / sumWeight)
}

View file

@ -1,6 +1,7 @@
package state package state
import ( import (
"crypto/elliptic"
"math/big" "math/big"
"github.com/nspcc-dev/neo-go/pkg/crypto/keys" "github.com/nspcc-dev/neo-go/pkg/crypto/keys"
@ -17,7 +18,7 @@ type NEP5BalanceState struct {
type NEOBalanceState struct { type NEOBalanceState struct {
NEP5BalanceState NEP5BalanceState
BalanceHeight uint32 BalanceHeight uint32
Votes keys.PublicKeys VoteTo *keys.PublicKey
} }
// NEP5BalanceStateFromBytes converts serialized NEP5BalanceState to structure. // NEP5BalanceStateFromBytes converts serialized NEP5BalanceState to structure.
@ -110,7 +111,11 @@ func (s *NEOBalanceState) DecodeBinary(r *io.BinReader) {
func (s *NEOBalanceState) toStackItem() stackitem.Item { func (s *NEOBalanceState) toStackItem() stackitem.Item {
result := s.NEP5BalanceState.toStackItem().(*stackitem.Struct) result := s.NEP5BalanceState.toStackItem().(*stackitem.Struct)
result.Append(stackitem.NewBigInteger(big.NewInt(int64(s.BalanceHeight)))) result.Append(stackitem.NewBigInteger(big.NewInt(int64(s.BalanceHeight))))
result.Append(stackitem.NewByteArray(s.Votes.Bytes())) if s.VoteTo != nil {
result.Append(stackitem.NewByteArray(s.VoteTo.Bytes()))
} else {
result.Append(stackitem.Null{})
}
return result return result
} }
@ -118,6 +123,18 @@ func (s *NEOBalanceState) fromStackItem(item stackitem.Item) error {
structItem := item.Value().([]stackitem.Item) structItem := item.Value().([]stackitem.Item)
s.Balance = *structItem[0].Value().(*big.Int) s.Balance = *structItem[0].Value().(*big.Int)
s.BalanceHeight = uint32(structItem[1].Value().(*big.Int).Int64()) s.BalanceHeight = uint32(structItem[1].Value().(*big.Int).Int64())
s.Votes = make(keys.PublicKeys, 0) if _, ok := structItem[2].(stackitem.Null); ok {
return s.Votes.DecodeBytes(structItem[2].Value().([]byte)) s.VoteTo = nil
return nil
}
bs, err := structItem[2].TryBytes()
if err != nil {
return err
}
pub, err := keys.NewPublicKeyFromBytes(bs, elliptic.P256())
if err != nil {
return err
}
s.VoteTo = pub
return nil
} }

View file

@ -1125,7 +1125,6 @@ func checkNep5Transfers(t *testing.T, e *executor, acc interface{}) {
TxHash: b.Hash(), TxHash: b.Hash(),
}) })
} }
} }
require.Equal(t, expected.Address, res.Address) require.Equal(t, expected.Address, res.Address)
require.ElementsMatch(t, expected.Sent, res.Sent) require.ElementsMatch(t, expected.Sent, res.Sent)