package native import ( "crypto/elliptic" "errors" "math/big" "sort" "strings" "sync/atomic" "github.com/nspcc-dev/neo-go/pkg/core/blockchainer" "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/runtime" "github.com/nspcc-dev/neo-go/pkg/core/state" "github.com/nspcc-dev/neo-go/pkg/crypto/hash" "github.com/nspcc-dev/neo-go/pkg/crypto/keys" "github.com/nspcc-dev/neo-go/pkg/encoding/bigint" "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/stackitem" ) // NEO represents NEO native contract. type NEO struct { nep5TokenNative GAS *GAS votesChanged atomic.Value nextValidators atomic.Value validators atomic.Value // committee contains cached committee members and // is updated once in a while depending on committee size // (every 28 blocks for mainnet). It's value // is always equal to value stored by `prefixCommittee`. committee atomic.Value // committeeHash contains script hash of the committee. committeeHash atomic.Value } // keyWithVotes is a serialized key with votes balance. It's not deserialized // because some uses of it imply serialized-only usage and converting to // PublicKey is quite expensive. type keyWithVotes struct { Key string Votes *big.Int } const ( neoName = "NEO" neoContractID = -1 // NEOTotalSupply is the total amount of NEO in the system. NEOTotalSupply = 100000000 // prefixCandidate is a prefix used to store validator's data. prefixCandidate = 33 // prefixVotersCount is a prefix for storing total amount of NEO of voters. prefixVotersCount = 1 // prefixGasPerBlock is a prefix for storing amount of GAS generated per block. prefixGASPerBlock = 29 // effectiveVoterTurnout represents minimal ratio of total supply to total amount voted value // which is require to use non-standby validators. effectiveVoterTurnout = 5 // neoHolderRewardRatio is a percent of generated GAS that is distributed to NEO holders. neoHolderRewardRatio = 10 // neoHolderRewardRatio is a percent of generated GAS that is distributed to committee. committeeRewardRatio = 5 // neoHolderRewardRatio is a percent of generated GAS that is distributed to voters. voterRewardRatio = 85 ) var ( // prefixCommittee is a key used to store committee. prefixCommittee = []byte{14} ) // makeValidatorKey creates a key from account script hash. func makeValidatorKey(key *keys.PublicKey) []byte { b := key.Bytes() // Don't create a new buffer. b = append(b, 0) copy(b[1:], b[0:]) b[0] = prefixCandidate return b } // NewNEO returns NEO native contract. func NewNEO() *NEO { n := &NEO{} nep5 := newNEP5Native(neoName) nep5.symbol = "neo" nep5.decimals = 0 nep5.factor = 1 nep5.onPersist = chainOnPersist(nep5.OnPersist, n.OnPersist) nep5.postPersist = chainOnPersist(nep5.postPersist, n.PostPersist) nep5.incBalance = n.increaseBalance nep5.ContractID = neoContractID n.nep5TokenNative = *nep5 n.votesChanged.Store(true) n.nextValidators.Store(keys.PublicKeys(nil)) n.validators.Store(keys.PublicKeys(nil)) n.committee.Store(keys.PublicKeys(nil)) n.committeeHash.Store(util.Uint160{}) onp := n.Methods["onPersist"] onp.Func = getOnPersistWrapper(n.onPersist) n.Methods["onPersist"] = onp pp := n.Methods["postPersist"] pp.Func = getOnPersistWrapper(n.postPersist) n.Methods["postPersist"] = pp desc := newDescriptor("unclaimedGas", smartcontract.IntegerType, manifest.NewParameter("account", smartcontract.Hash160Type), manifest.NewParameter("end", smartcontract.IntegerType)) md := newMethodAndPrice(n.unclaimedGas, 3000000, smartcontract.AllowStates) n.AddMethod(md, desc, true) desc = newDescriptor("registerCandidate", smartcontract.BoolType, manifest.NewParameter("pubkey", smartcontract.PublicKeyType)) md = newMethodAndPrice(n.registerCandidate, 5000000, smartcontract.AllowModifyStates) n.AddMethod(md, desc, false) desc = newDescriptor("unregisterCandidate", smartcontract.BoolType, manifest.NewParameter("pubkey", smartcontract.PublicKeyType)) md = newMethodAndPrice(n.unregisterCandidate, 5000000, smartcontract.AllowModifyStates) n.AddMethod(md, desc, false) desc = newDescriptor("vote", smartcontract.BoolType, manifest.NewParameter("account", smartcontract.Hash160Type), manifest.NewParameter("pubkey", smartcontract.PublicKeyType)) md = newMethodAndPrice(n.vote, 500000000, smartcontract.AllowModifyStates) n.AddMethod(md, desc, false) desc = newDescriptor("getCandidates", smartcontract.ArrayType) md = newMethodAndPrice(n.getCandidatesCall, 100000000, smartcontract.AllowStates) n.AddMethod(md, desc, true) desc = newDescriptor("getŠ”ommittee", smartcontract.ArrayType) md = newMethodAndPrice(n.getCommittee, 100000000, smartcontract.AllowStates) n.AddMethod(md, desc, true) desc = newDescriptor("getNextBlockValidators", smartcontract.ArrayType) md = newMethodAndPrice(n.getNextBlockValidators, 100000000, smartcontract.AllowStates) n.AddMethod(md, desc, true) desc = newDescriptor("getGasPerBlock", smartcontract.IntegerType) md = newMethodAndPrice(n.getGASPerBlock, 100_0000, smartcontract.AllowStates) n.AddMethod(md, desc, false) desc = newDescriptor("setGasPerBlock", smartcontract.BoolType, manifest.NewParameter("gasPerBlock", smartcontract.IntegerType)) md = newMethodAndPrice(n.setGASPerBlock, 500_0000, smartcontract.AllowModifyStates) n.AddMethod(md, desc, false) return n } // Initialize initializes NEO contract. func (n *NEO) Initialize(ic *interop.Context) error { if err := n.nep5TokenNative.Initialize(ic); err != nil { return err } if n.nep5TokenNative.getTotalSupply(ic.DAO).Sign() != 0 { return errors.New("already initialized") } committee := ic.Chain.GetStandByCommittee() n.committee.Store(committee) script, err := smartcontract.CreateMajorityMultiSigRedeemScript(committee.Copy()) if err != nil { return err } n.committeeHash.Store(hash.Hash160(script)) n.updateNextValidators(committee, ic.Chain) err = ic.DAO.PutStorageItem(n.ContractID, prefixCommittee, &state.StorageItem{Value: committee.Bytes()}) if err != nil { return err } h, err := getStandbyValidatorsHash(ic) if err != nil { return err } n.mint(ic, h, big.NewInt(NEOTotalSupply)) gr := &state.GASRecord{{Index: 0, GASPerBlock: *big.NewInt(5 * GASFactor)}} err = ic.DAO.PutStorageItem(n.ContractID, []byte{prefixGASPerBlock}, &state.StorageItem{Value: gr.Bytes()}) if err != nil { return err } err = ic.DAO.PutStorageItem(n.ContractID, []byte{prefixVotersCount}, &state.StorageItem{Value: []byte{}}) if err != nil { return err } return nil } func (n *NEO) updateNextValidators(committee keys.PublicKeys, bc blockchainer.Blockchainer) { nextVals := committee[:bc.GetConfig().ValidatorsCount].Copy() sort.Sort(nextVals) n.nextValidators.Store(nextVals) } func (n *NEO) updateCommittee(ic *interop.Context) error { votesChanged := n.votesChanged.Load().(bool) if !votesChanged { // We need to put in storage anyway, as it affects dumps committee := n.committee.Load().(keys.PublicKeys) si := &state.StorageItem{Value: committee.Bytes()} return ic.DAO.PutStorageItem(n.ContractID, prefixCommittee, si) } committee, err := n.ComputeCommitteeMembers(ic.Chain, ic.DAO) if err != nil { return err } n.committee.Store(committee) script, err := smartcontract.CreateMajorityMultiSigRedeemScript(committee.Copy()) if err != nil { return err } n.committeeHash.Store(hash.Hash160(script)) n.updateNextValidators(committee, ic.Chain) n.votesChanged.Store(false) si := &state.StorageItem{Value: committee.Bytes()} return ic.DAO.PutStorageItem(n.ContractID, prefixCommittee, si) } func shouldUpdateCommittee(h uint32, bc blockchainer.Blockchainer) bool { cfg := bc.GetConfig() r := cfg.ValidatorsCount + len(cfg.StandbyCommittee) return h%uint32(r) == 0 } // OnPersist implements Contract interface. func (n *NEO) OnPersist(ic *interop.Context) error { if shouldUpdateCommittee(ic.Block.Index, ic.Chain) { if err := n.updateCommittee(ic); err != nil { return err } } return nil } // PostPersist implements Contract interface. func (n *NEO) PostPersist(ic *interop.Context) error { gas, err := n.GetGASPerBlock(ic, ic.Block.Index) if err != nil { return err } pubs := n.GetCommitteeMembers() index := int(ic.Block.Index) % len(ic.Chain.GetConfig().StandbyCommittee) gas.Mul(gas, big.NewInt(committeeRewardRatio)) n.GAS.mint(ic, pubs[index].GetScriptHash(), gas.Div(gas, big.NewInt(100))) return nil } func (n *NEO) increaseBalance(ic *interop.Context, h util.Uint160, si *state.StorageItem, amount *big.Int) error { acc, err := state.NEOBalanceStateFromBytes(si.Value) if err != nil { return err } if amount.Sign() == -1 && acc.Balance.Cmp(new(big.Int).Neg(amount)) == -1 { return errors.New("insufficient funds") } if err := n.distributeGas(ic, h, acc); err != nil { return err } if amount.Sign() == 0 { si.Value = acc.Bytes() return nil } if err := n.ModifyAccountVotes(acc, ic.DAO, amount, modifyVoteTransfer); err != nil { return err } if acc.VoteTo != nil { if err := n.modifyVoterTurnout(ic.DAO, amount); err != nil { return err } } acc.Balance.Add(&acc.Balance, amount) if acc.Balance.Sign() != 0 { si.Value = acc.Bytes() } else { si.Value = nil } return nil } func (n *NEO) distributeGas(ic *interop.Context, h util.Uint160, acc *state.NEOBalanceState) error { if ic.Block == nil || ic.Block.Index == 0 { return nil } gen, err := n.CalculateBonus(ic, &acc.Balance, acc.BalanceHeight, ic.Block.Index) if err != nil { return err } acc.BalanceHeight = ic.Block.Index n.GAS.mint(ic, h, gen) return nil } func (n *NEO) unclaimedGas(ic *interop.Context, args []stackitem.Item) stackitem.Item { u := toUint160(args[0]) end := uint32(toBigInt(args[1]).Int64()) bs, err := ic.DAO.GetNEP5Balances(u) if err != nil { panic(err) } tr := bs.Trackers[n.ContractID] gen, err := n.CalculateBonus(ic, &tr.Balance, tr.LastUpdatedBlock, end) if err != nil { panic(err) } return stackitem.NewBigInteger(gen) } func (n *NEO) getGASPerBlock(ic *interop.Context, _ []stackitem.Item) stackitem.Item { gas, err := n.GetGASPerBlock(ic, ic.Block.Index) if err != nil { panic(err) } return stackitem.NewBigInteger(gas) } // GetGASPerBlock returns gas generated for block with provided index. func (n *NEO) GetGASPerBlock(ic *interop.Context, index uint32) (*big.Int, error) { si := ic.DAO.GetStorageItem(n.ContractID, []byte{prefixGASPerBlock}) var gr state.GASRecord if err := gr.FromBytes(si.Value); err != nil { return nil, err } for i := len(gr) - 1; i >= 0; i-- { if gr[i].Index <= index { return &gr[i].GASPerBlock, nil } } return nil, errors.New("contract not initialized") } // GetCommitteeAddress returns address of the committee. func (n *NEO) GetCommitteeAddress() util.Uint160 { return n.committeeHash.Load().(util.Uint160) } func (n *NEO) setGASPerBlock(ic *interop.Context, args []stackitem.Item) stackitem.Item { gas := toBigInt(args[0]) ok, err := n.SetGASPerBlock(ic, ic.Block.Index+1, gas) if err != nil { panic(err) } return stackitem.NewBool(ok) } // SetGASPerBlock sets gas generated for blocks after index. func (n *NEO) SetGASPerBlock(ic *interop.Context, index uint32, gas *big.Int) (bool, error) { if gas.Sign() == -1 || gas.Cmp(big.NewInt(10*GASFactor)) == 1 { return false, errors.New("invalid value for GASPerBlock") } h := n.GetCommitteeAddress() ok, err := runtime.CheckHashedWitness(ic, h) if err != nil || !ok { return ok, err } si := ic.DAO.GetStorageItem(n.ContractID, []byte{prefixGASPerBlock}) var gr state.GASRecord if err := gr.FromBytes(si.Value); err != nil { return false, err } if len(gr) > 0 && gr[len(gr)-1].Index == index { gr[len(gr)-1].GASPerBlock = *gas } else { gr = append(gr, state.GASIndexPair{ Index: index, GASPerBlock: *gas, }) } return true, ic.DAO.PutStorageItem(n.ContractID, []byte{prefixGASPerBlock}, &state.StorageItem{Value: gr.Bytes()}) } // CalculateBonus calculates amount of gas generated for holding `value` NEO from start to end block. func (n *NEO) CalculateBonus(ic *interop.Context, value *big.Int, start, end uint32) (*big.Int, error) { if value.Sign() == 0 || start >= end { return big.NewInt(0), nil } else if value.Sign() < 0 { return nil, errors.New("negative value") } si := ic.DAO.GetStorageItem(n.ContractID, []byte{prefixGASPerBlock}) var gr state.GASRecord if err := gr.FromBytes(si.Value); err != nil { return nil, err } var sum, tmp big.Int for i := len(gr) - 1; i >= 0; i-- { if gr[i].Index >= end { continue } else if gr[i].Index <= start { tmp.SetInt64(int64(end - start)) tmp.Mul(&tmp, &gr[i].GASPerBlock) sum.Add(&sum, &tmp) break } tmp.SetInt64(int64(end - gr[i].Index)) tmp.Mul(&tmp, &gr[i].GASPerBlock) sum.Add(&sum, &tmp) end = gr[i].Index } res := new(big.Int).Mul(value, &sum) res.Mul(res, tmp.SetInt64(neoHolderRewardRatio)) res.Div(res, tmp.SetInt64(100*NEOTotalSupply)) return res, nil } func (n *NEO) registerCandidate(ic *interop.Context, args []stackitem.Item) stackitem.Item { pub := toPublicKey(args[0]) ok, err := runtime.CheckKeyedWitness(ic, pub) if err != nil { panic(err) } else if !ok { return stackitem.NewBool(false) } err = n.RegisterCandidateInternal(ic, pub) return stackitem.NewBool(err == nil) } // RegisterCandidateInternal registers pub as a new candidate. func (n *NEO) RegisterCandidateInternal(ic *interop.Context, pub *keys.PublicKey) error { key := makeValidatorKey(pub) si := ic.DAO.GetStorageItem(n.ContractID, key) if si == nil { c := &candidate{Registered: true} si = &state.StorageItem{Value: c.Bytes()} } else { c := new(candidate).FromBytes(si.Value) c.Registered = true si.Value = c.Bytes() } return ic.DAO.PutStorageItem(n.ContractID, key, si) } func (n *NEO) unregisterCandidate(ic *interop.Context, args []stackitem.Item) stackitem.Item { pub := toPublicKey(args[0]) ok, err := runtime.CheckKeyedWitness(ic, pub) if err != nil { panic(err) } else if !ok { return stackitem.NewBool(false) } err = n.UnregisterCandidateInternal(ic, pub) return stackitem.NewBool(err == nil) } // UnregisterCandidateInternal unregisters pub as a candidate. func (n *NEO) UnregisterCandidateInternal(ic *interop.Context, pub *keys.PublicKey) error { key := makeValidatorKey(pub) si := ic.DAO.GetStorageItem(n.ContractID, key) if si == nil { return nil } n.validators.Store(keys.PublicKeys(nil)) c := new(candidate).FromBytes(si.Value) if c.Votes.Sign() == 0 { return ic.DAO.DeleteStorageItem(n.ContractID, key) } c.Registered = false si.Value = c.Bytes() return ic.DAO.PutStorageItem(n.ContractID, key, si) } func (n *NEO) vote(ic *interop.Context, args []stackitem.Item) stackitem.Item { acc := toUint160(args[0]) var pub *keys.PublicKey if _, ok := args[1].(stackitem.Null); !ok { pub = toPublicKey(args[1]) } err := n.VoteInternal(ic, acc, pub) return stackitem.NewBool(err == nil) } // VoteInternal votes from account h for validarors specified in pubs. func (n *NEO) VoteInternal(ic *interop.Context, h util.Uint160, pub *keys.PublicKey) error { ok, err := runtime.CheckHashedWitness(ic, h) if err != nil { return err } else if !ok { return errors.New("invalid signature") } key := makeAccountKey(h) si := ic.DAO.GetStorageItem(n.ContractID, key) if si == nil { return errors.New("invalid account") } acc, err := state.NEOBalanceStateFromBytes(si.Value) if err != nil { return err } if (acc.VoteTo == nil) != (pub == nil) { val := &acc.Balance if pub == nil { val = new(big.Int).Neg(val) } if err := n.modifyVoterTurnout(ic.DAO, val); err != nil { return err } } if err := n.ModifyAccountVotes(acc, ic.DAO, new(big.Int).Neg(&acc.Balance), modifyVoteOld); err != nil { return err } acc.VoteTo = pub if err := n.ModifyAccountVotes(acc, ic.DAO, &acc.Balance, modifyVoteNew); err != nil { return err } si.Value = acc.Bytes() 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). // typ specifies if this modify is occurring during transfer or vote (with old or new validator). func (n *NEO) ModifyAccountVotes(acc *state.NEOBalanceState, d dao.DAO, value *big.Int, typ int) error { n.votesChanged.Store(true) if acc.VoteTo != nil { key := makeValidatorKey(acc.VoteTo) si := d.GetStorageItem(n.ContractID, key) if si == nil { return errors.New("invalid validator") } cd := new(candidate).FromBytes(si.Value) cd.Votes.Add(&cd.Votes, value) switch typ { case modifyVoteOld: 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)) si.Value = cd.Bytes() return d.PutStorageItem(n.ContractID, key, si) } return nil } func (n *NEO) getCandidates(d dao.DAO) ([]keyWithVotes, error) { siMap, err := d.GetStorageItemsWithPrefix(n.ContractID, []byte{prefixCandidate}) if err != nil { return nil, err } arr := make([]keyWithVotes, 0, len(siMap)) for key, si := range siMap { c := new(candidate).FromBytes(si.Value) 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 }) return arr, nil } // GetCandidates returns current registered validators list with keys // and votes. func (n *NEO) GetCandidates(d dao.DAO) ([]state.Validator, error) { kvs, err := n.getCandidates(d) if err != nil { return nil, err } arr := make([]state.Validator, len(kvs)) for i := range kvs { arr[i].Key, err = keys.NewPublicKeyFromBytes([]byte(kvs[i].Key), elliptic.P256()) if err != nil { return nil, err } arr[i].Votes = kvs[i].Votes } return arr, nil } func (n *NEO) getCandidatesCall(ic *interop.Context, _ []stackitem.Item) stackitem.Item { validators, err := n.getCandidates(ic.DAO) if err != nil { panic(err) } arr := make([]stackitem.Item, len(validators)) for i := range validators { arr[i] = stackitem.NewStruct([]stackitem.Item{ stackitem.NewByteArray([]byte(validators[i].Key)), stackitem.NewBigInteger(validators[i].Votes), }) } return stackitem.NewArray(arr) } // ComputeNextBlockValidators returns an actual list of current validators. func (n *NEO) ComputeNextBlockValidators(bc blockchainer.Blockchainer, d dao.DAO) (keys.PublicKeys, error) { if vals := n.validators.Load().(keys.PublicKeys); vals != nil { return vals.Copy(), nil } result, err := n.ComputeCommitteeMembers(bc, d) if err != nil { return nil, err } result = result[:bc.GetConfig().ValidatorsCount] sort.Sort(result) n.validators.Store(result) return result, nil } func (n *NEO) getCommittee(ic *interop.Context, _ []stackitem.Item) stackitem.Item { pubs := n.GetCommitteeMembers() 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) } // GetCommitteeMembers returns public keys of nodes in committee using cached value. func (n *NEO) GetCommitteeMembers() keys.PublicKeys { return n.committee.Load().(keys.PublicKeys).Copy() } // ComputeCommitteeMembers returns public keys of nodes in committee. func (n *NEO) ComputeCommitteeMembers(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 { pubs := bc.GetStandByCommittee() return pubs, nil } cs, err := n.getCandidates(d) if err != nil { return nil, err } sbVals := bc.GetStandByCommittee() 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 { result := n.GetNextBlockValidatorsInternal() return pubsToArray(result) } // GetNextBlockValidatorsInternal returns next block validators. func (n *NEO) GetNextBlockValidatorsInternal() keys.PublicKeys { return n.nextValidators.Load().(keys.PublicKeys).Copy() } func pubsToArray(pubs keys.PublicKeys) stackitem.Item { arr := make([]stackitem.Item, len(pubs)) for i := range pubs { arr[i] = stackitem.NewByteArray(pubs[i].Bytes()) } return stackitem.NewArray(arr) } func toPublicKey(s stackitem.Item) *keys.PublicKey { buf, err := s.TryBytes() if err != nil { panic(err) } pub := new(keys.PublicKey) if err := pub.DecodeBytes(buf); err != nil { panic(err) } return pub }