Merge pull request #1090 from nspcc-dev/feature/protocol

Enable state root exchange base on config

config/protocol.testnet.yml

@@ -2,6 +2,8 @@ ProtocolConfiguration:
   Magic: 1953787457
   AddressVersion: 23
   SecondsPerBlock: 15
+  EnableStateRoot: true
+  StateRootEnableIndex: 4380100
   LowPriorityThreshold: 0.000
   MemPoolSize: 50000
   StandbyValidators:

config/protocol.unit_testnet.yml

@@ -2,6 +2,7 @@ ProtocolConfiguration:
   Magic: 56753
   AddressVersion: 23
   SecondsPerBlock: 15
+  EnableStateRoot: true
   LowPriorityThreshold: 0.000
   MemPoolSize: 50000
   StandbyValidators:

pkg/config/protocol_config.go

@@ -20,6 +20,8 @@ const (
 type (
 	ProtocolConfiguration struct {
 		AddressVersion byte `yaml:"AddressVersion"`
+		// EnableStateRoot specifies if exchange of state roots should be enabled.
+		EnableStateRoot bool `yaml:"EnableStateRoot"`
 		// FeePerExtraByte sets the expected per-byte fee for
 		// transactions exceeding the MaxFreeTransactionSize.
 		FeePerExtraByte float64 `yaml:"FeePerExtraByte"`
@@ -34,11 +36,13 @@ type (
 		MaxFreeTransactionsPerBlock int `yaml:"MaxFreeTransactionsPerBlock"`
 		MemPoolSize                 int `yaml:"MemPoolSize"`
 		// SaveStorageBatch enables storage batch saving before every persist.
-		SaveStorageBatch  bool      `yaml:"SaveStorageBatch"`
-		SecondsPerBlock   int       `yaml:"SecondsPerBlock"`
-		SeedList          []string  `yaml:"SeedList"`
-		StandbyValidators []string  `yaml:"StandbyValidators"`
-		SystemFee         SystemFee `yaml:"SystemFee"`
+		SaveStorageBatch  bool     `yaml:"SaveStorageBatch"`
+		SecondsPerBlock   int      `yaml:"SecondsPerBlock"`
+		SeedList          []string `yaml:"SeedList"`
+		StandbyValidators []string `yaml:"StandbyValidators"`
+		// StateRootEnableIndex specifies starting height for state root calculations and exchange.
+		StateRootEnableIndex uint32    `yaml:"StateRootEnableIndex"`
+		SystemFee            SystemFee `yaml:"SystemFee"`
 		// Whether to verify received blocks.
 		VerifyBlocks bool `yaml:"VerifyBlocks"`
 		// Whether to verify transactions in received blocks.

pkg/consensus/commit.go

@@ -9,6 +9,8 @@ import (
 type commit struct {
 	signature [signatureSize]byte
 	stateSig  [signatureSize]byte
+
+	stateRootEnabled bool
 }
 
 // signatureSize is an rfc6989 signature size in bytes
@@ -20,13 +22,17 @@ var _ payload.Commit = (*commit)(nil)
 // EncodeBinary implements io.Serializable interface.
 func (c *commit) EncodeBinary(w *io.BinWriter) {
 	w.WriteBytes(c.signature[:])
-	w.WriteBytes(c.stateSig[:])
+	if c.stateRootEnabled {
+		w.WriteBytes(c.stateSig[:])
+	}
 }
 
 // DecodeBinary implements io.Serializable interface.
 func (c *commit) DecodeBinary(r *io.BinReader) {
 	r.ReadBytes(c.signature[:])
-	r.ReadBytes(c.stateSig[:])
+	if c.stateRootEnabled {
+		r.ReadBytes(c.stateSig[:])
+	}
 }
 
 // Signature implements payload.Commit interface.

pkg/consensus/consensus.go

@@ -138,7 +138,7 @@ func NewService(cfg Config) (Service, error) {
 		dbft.WithGetValidators(srv.getValidators),
 		dbft.WithGetConsensusAddress(srv.getConsensusAddress),
 
-		dbft.WithNewConsensusPayload(func() payload.ConsensusPayload { p := new(Payload); p.message = &message{}; return p }),
+		dbft.WithNewConsensusPayload(srv.newPayload),
 		dbft.WithNewPrepareRequest(srv.newPrepareRequest),
 		dbft.WithNewPrepareResponse(func() payload.PrepareResponse { return new(prepareResponse) }),
 		dbft.WithNewChangeView(func() payload.ChangeView { return new(changeView) }),
@@ -214,31 +214,51 @@ func (s *service) eventLoop() {
 	}
 }
 
-func (s *service) newPrepareRequest() payload.PrepareRequest {
-	sr, err := s.Chain.GetStateRoot(s.Chain.BlockHeight())
-	if err != nil {
-		return new(prepareRequest)
-	}
-	return &prepareRequest{
-		proposalStateRoot: sr.MPTRootBase,
+func (s *service) newPayload() payload.ConsensusPayload {
+	return &Payload{
+		message: &message{
+			stateRootEnabled: s.stateRootEnabled(),
+		},
 	}
 }
 
+// stateRootEnabled checks if state root feature is enabled on current height.
+// It should be called only from dbft callbacks and is not protected by any mutex.
+func (s *service) stateRootEnabled() bool {
+	return s.Chain.GetConfig().EnableStateRoot
+}
+
+func (s *service) newPrepareRequest() payload.PrepareRequest {
+	if !s.stateRootEnabled() {
+		return new(prepareRequest)
+	}
+	sr, err := s.Chain.GetStateRoot(s.Chain.BlockHeight())
+	if err == nil {
+		return &prepareRequest{
+			stateRootEnabled:  true,
+			proposalStateRoot: sr.MPTRootBase,
+		}
+	}
+	return &prepareRequest{stateRootEnabled: true}
+}
+
 func (s *service) newCommit() payload.Commit {
+	if !s.stateRootEnabled() {
+		return new(commit)
+	}
+	c := &commit{stateRootEnabled: true}
 	for _, p := range s.dbft.Context.PreparationPayloads {
 		if p != nil && p.ViewNumber() == s.dbft.ViewNumber && p.Type() == payload.PrepareRequestType {
 			pr := p.GetPrepareRequest().(*prepareRequest)
 			data := pr.proposalStateRoot.GetSignedPart()
 			sign, err := s.dbft.Priv.Sign(data)
 			if err == nil {
-				var c commit
 				copy(c.stateSig[:], sign)
-				return &c
 			}
 			break
 		}
 	}
-	return new(commit)
+	return c
 }
 
 func (s *service) validatePayload(p *Payload) bool {
@@ -293,8 +313,8 @@ func (s *service) OnPayload(cp *Payload) {
 
 	// decode payload data into message
 	if cp.message == nil {
-		if err := cp.decodeData(); err != nil {
-			log.Debug("can't decode payload data")
+		if err := cp.decodeData(s.stateRootEnabled()); err != nil {
+			log.Debug("can't decode payload data", zap.Error(err))
 			return
 		}
 	}
@@ -372,6 +392,9 @@ func (s *service) verifyBlock(b block.Block) bool {
 }
 
 func (s *service) verifyRequest(p payload.ConsensusPayload) error {
+	if !s.stateRootEnabled() {
+		return nil
+	}
 	r, err := s.Chain.GetStateRoot(s.dbft.BlockIndex - 1)
 	if err != nil {
 		return fmt.Errorf("can't get local state root: %v", err)

pkg/consensus/payload.go

@@ -22,6 +22,8 @@ type (
 		Type       messageType
 		ViewNumber byte
 
+		stateRootEnabled bool
+
 		payload io.Serializable
 	}
 
@@ -283,15 +285,21 @@ func (m *message) DecodeBinary(r *io.BinReader) {
 		cv.newViewNumber = m.ViewNumber + 1
 		m.payload = cv
 	case prepareRequestType:
-		m.payload = new(prepareRequest)
+		m.payload = &prepareRequest{
+			stateRootEnabled: m.stateRootEnabled,
+		}
 	case prepareResponseType:
 		m.payload = new(prepareResponse)
 	case commitType:
-		m.payload = new(commit)
+		m.payload = &commit{
+			stateRootEnabled: m.stateRootEnabled,
+		}
 	case recoveryRequestType:
 		m.payload = new(recoveryRequest)
 	case recoveryMessageType:
-		m.payload = new(recoveryMessage)
+		m.payload = &recoveryMessage{
+			stateRootEnabled: m.stateRootEnabled,
+		}
 	default:
 		r.Err = errors.Errorf("invalid type: 0x%02x", byte(m.Type))
 		return
@@ -319,9 +327,9 @@ func (t messageType) String() string {
 	}
 }
 
-// decode data of payload into it's message
-func (p *Payload) decodeData() error {
-	m := new(message)
+// decodeData decodes data of payload into it's message.
+func (p *Payload) decodeData(stateRootEnabled bool) error {
+	m := &message{stateRootEnabled: stateRootEnabled}
 	br := io.NewBinReaderFromBuf(p.data)
 	m.DecodeBinary(br)
 	if br.Err != nil {

pkg/consensus/payload_test.go

@@ -94,13 +94,13 @@ func TestConsensusPayload_Serializable(t *testing.T) {
 		// message is nil after decoding as we didn't yet call decodeData
 		require.Nil(t, actual.message)
 		// message should now be decoded from actual.data byte array
-		assert.NoError(t, actual.decodeData())
+		assert.NoError(t, actual.decodeData(false))
 		require.Equal(t, p, actual)
 
 		data = p.MarshalUnsigned()
 		pu := new(Payload)
 		require.NoError(t, pu.UnmarshalUnsigned(data))
-		assert.NoError(t, pu.decodeData())
+		assert.NoError(t, pu.decodeData(false))
 
 		p.Witness = transaction.Witness{}
 		require.Equal(t, p, pu)
@@ -144,14 +144,14 @@ func TestConsensusPayload_DecodeBinaryInvalid(t *testing.T) {
 	p := new(Payload)
 	require.NoError(t, testserdes.DecodeBinary(buf, p))
 	// decode `data` into `message`
-	assert.NoError(t, p.decodeData())
+	assert.NoError(t, p.decodeData(false))
 	require.Equal(t, expected, p)
 
 	// invalid type
 	buf[typeIndex] = 0xFF
 	actual := new(Payload)
 	require.NoError(t, testserdes.DecodeBinary(buf, actual))
-	require.Error(t, actual.decodeData())
+	require.Error(t, actual.decodeData(false))
 
 	// invalid format
 	buf[delimeterIndex] = 0
@@ -165,9 +165,16 @@ func TestConsensusPayload_DecodeBinaryInvalid(t *testing.T) {
 	require.Error(t, testserdes.DecodeBinary(buf, new(Payload)))
 }
 
+func testEncodeDecode(srEnabled bool, mt messageType, actual io.Serializable) func(t *testing.T) {
+	return func(t *testing.T) {
+		expected := randomMessage(t, mt, srEnabled)
+		testserdes.EncodeDecodeBinary(t, expected, actual)
+	}
+}
+
 func TestCommit_Serializable(t *testing.T) {
-	c := randomMessage(t, commitType)
-	testserdes.EncodeDecodeBinary(t, c, new(commit))
+	t.Run("WithStateRoot", testEncodeDecode(true, commitType, &commit{stateRootEnabled: true}))
+	t.Run("NoStateRoot", testEncodeDecode(false, commitType, &commit{stateRootEnabled: false}))
 }
 
 func TestPrepareResponse_Serializable(t *testing.T) {
@@ -176,8 +183,8 @@ func TestPrepareResponse_Serializable(t *testing.T) {
 }
 
 func TestPrepareRequest_Serializable(t *testing.T) {
-	req := randomMessage(t, prepareRequestType)
-	testserdes.EncodeDecodeBinary(t, req, new(prepareRequest))
+	t.Run("WithStateRoot", testEncodeDecode(true, prepareRequestType, &prepareRequest{stateRootEnabled: true}))
+	t.Run("NoStateRoot", testEncodeDecode(false, prepareRequestType, &prepareRequest{stateRootEnabled: false}))
 }
 
 func TestRecoveryRequest_Serializable(t *testing.T) {
@@ -186,8 +193,8 @@ func TestRecoveryRequest_Serializable(t *testing.T) {
 }
 
 func TestRecoveryMessage_Serializable(t *testing.T) {
-	msg := randomMessage(t, recoveryMessageType)
-	testserdes.EncodeDecodeBinary(t, msg, new(recoveryMessage))
+	t.Run("WithStateRoot", testEncodeDecode(true, recoveryMessageType, &recoveryMessage{stateRootEnabled: true}))
+	t.Run("NoStateRoot", testEncodeDecode(false, recoveryMessageType, &recoveryMessage{stateRootEnabled: false}))
 }
 
 func randomPayload(t *testing.T, mt messageType) *Payload {
@@ -215,32 +222,35 @@ func randomPayload(t *testing.T, mt messageType) *Payload {
 	return p
 }
 
-func randomMessage(t *testing.T, mt messageType) io.Serializable {
+func randomMessage(t *testing.T, mt messageType, srEnabled ...bool) io.Serializable {
 	switch mt {
 	case changeViewType:
 		return &changeView{
 			timestamp: rand.Uint32(),
 		}
 	case prepareRequestType:
-		return randomPrepareRequest(t)
+		return randomPrepareRequest(t, srEnabled...)
 	case prepareResponseType:
 		return &prepareResponse{preparationHash: random.Uint256()}
 	case commitType:
 		var c commit
 		random.Fill(c.signature[:])
-		random.Fill(c.stateSig[:])
+		if len(srEnabled) > 0 && srEnabled[0] {
+			c.stateRootEnabled = true
+			random.Fill(c.stateSig[:])
+		}
 		return &c
 	case recoveryRequestType:
 		return &recoveryRequest{timestamp: rand.Uint32()}
 	case recoveryMessageType:
-		return randomRecoveryMessage(t)
+		return randomRecoveryMessage(t, srEnabled...)
 	default:
 		require.Fail(t, "invalid type")
 		return nil
 	}
 }
 
-func randomPrepareRequest(t *testing.T) *prepareRequest {
+func randomPrepareRequest(t *testing.T, srEnabled ...bool) *prepareRequest {
 	const txCount = 3
 
 	req := &prepareRequest{
@@ -256,15 +266,22 @@ func randomPrepareRequest(t *testing.T) *prepareRequest {
 	}
 	req.nextConsensus = random.Uint160()
 
+	if len(srEnabled) > 0 && srEnabled[0] {
+		req.stateRootEnabled = true
+		req.proposalStateRoot.Index = rand.Uint32()
+		req.proposalStateRoot.PrevHash = random.Uint256()
+		req.proposalStateRoot.Root = random.Uint256()
+	}
+
 	return req
 }
 
-func randomRecoveryMessage(t *testing.T) *recoveryMessage {
-	result := randomMessage(t, prepareRequestType)
+func randomRecoveryMessage(t *testing.T, srEnabled ...bool) *recoveryMessage {
+	result := randomMessage(t, prepareRequestType, srEnabled...)
 	require.IsType(t, (*prepareRequest)(nil), result)
 	prepReq := result.(*prepareRequest)
 
-	return &recoveryMessage{
+	rec := &recoveryMessage{
 		preparationPayloads: []*preparationCompact{
 			{
 				ValidatorIndex:   1,
@@ -276,14 +293,12 @@ func randomRecoveryMessage(t *testing.T) *recoveryMessage {
 				ViewNumber:       0,
 				ValidatorIndex:   1,
 				Signature:        [64]byte{1, 2, 3},
-				StateSignature:   [64]byte{4, 5, 6},
 				InvocationScript: random.Bytes(20),
 			},
 			{
 				ViewNumber:       0,
 				ValidatorIndex:   2,
 				Signature:        [64]byte{11, 3, 4, 98},
-				StateSignature:   [64]byte{4, 8, 15, 16, 23, 42},
 				InvocationScript: random.Bytes(10),
 			},
 		},
@@ -300,6 +315,15 @@ func randomRecoveryMessage(t *testing.T) *recoveryMessage {
 			payload: prepReq,
 		},
 	}
+	if len(srEnabled) > 0 && srEnabled[0] {
+		rec.stateRootEnabled = true
+		rec.prepareRequest.stateRootEnabled = true
+		for _, c := range rec.commitPayloads {
+			c.stateRootEnabled = true
+			random.Fill(c.StateSignature[:])
+		}
+	}
+	return rec
 }
 
 func TestPayload_Sign(t *testing.T) {

pkg/consensus/prepare_request.go

@@ -16,6 +16,8 @@ type prepareRequest struct {
 	minerTx           transaction.Transaction
 	nextConsensus     util.Uint160
 	proposalStateRoot state.MPTRootBase
+
+	stateRootEnabled bool
 }
 
 var _ payload.PrepareRequest = (*prepareRequest)(nil)
@@ -27,7 +29,9 @@ func (p *prepareRequest) EncodeBinary(w *io.BinWriter) {
 	w.WriteBytes(p.nextConsensus[:])
 	w.WriteArray(p.transactionHashes)
 	p.minerTx.EncodeBinary(w)
-	p.proposalStateRoot.EncodeBinary(w)
+	if p.stateRootEnabled {
+		p.proposalStateRoot.EncodeBinary(w)
+	}
 }
 
 // DecodeBinary implements io.Serializable interface.
@@ -37,7 +41,9 @@ func (p *prepareRequest) DecodeBinary(r *io.BinReader) {
 	r.ReadBytes(p.nextConsensus[:])
 	r.ReadArray(&p.transactionHashes)
 	p.minerTx.DecodeBinary(r)
-	p.proposalStateRoot.DecodeBinary(r)
+	if p.stateRootEnabled {
+		p.proposalStateRoot.DecodeBinary(r)
+	}
 }
 
 // Timestamp implements payload.PrepareRequest interface.

pkg/consensus/recovery_message.go

@@ -3,6 +3,7 @@ package consensus
 import (
 	"github.com/nspcc-dev/dbft/crypto"
 	"github.com/nspcc-dev/dbft/payload"
+	"github.com/nspcc-dev/neo-go/pkg/core/state"
 	"github.com/nspcc-dev/neo-go/pkg/io"
 	"github.com/nspcc-dev/neo-go/pkg/util"
 	"github.com/pkg/errors"
@@ -16,6 +17,8 @@ type (
 		commitPayloads      []*commitCompact
 		changeViewPayloads  []*changeViewCompact
 		prepareRequest      *message
+
+		stateRootEnabled bool
 	}
 
 	changeViewCompact struct {
@@ -31,6 +34,8 @@ type (
 		Signature        [signatureSize]byte
 		StateSignature   [signatureSize]byte
 		InvocationScript []byte
+
+		stateRootEnabled bool
 	}
 
 	preparationCompact struct {
@@ -47,7 +52,7 @@ func (m *recoveryMessage) DecodeBinary(r *io.BinReader) {
 
 	var hasReq = r.ReadBool()
 	if hasReq {
-		m.prepareRequest = new(message)
+		m.prepareRequest = &message{stateRootEnabled: m.stateRootEnabled}
 		m.prepareRequest.DecodeBinary(r)
 		if r.Err == nil && m.prepareRequest.Type != prepareRequestType {
 			r.Err = errors.New("recovery message PrepareRequest has wrong type")
@@ -68,7 +73,16 @@ func (m *recoveryMessage) DecodeBinary(r *io.BinReader) {
 	}
 
 	r.ReadArray(&m.preparationPayloads)
-	r.ReadArray(&m.commitPayloads)
+	lu := r.ReadVarUint()
+	if lu > state.MaxValidatorsVoted {
+		r.Err = errors.New("too many preparation payloads")
+		return
+	}
+	m.commitPayloads = make([]*commitCompact, lu)
+	for i := uint64(0); i < lu; i++ {
+		m.commitPayloads[i] = &commitCompact{stateRootEnabled: m.stateRootEnabled}
+		m.commitPayloads[i].DecodeBinary(r)
+	}
 }
 
 // EncodeBinary implements io.Serializable interface.
@@ -113,7 +127,9 @@ func (p *commitCompact) DecodeBinary(r *io.BinReader) {
 	p.ViewNumber = r.ReadB()
 	p.ValidatorIndex = r.ReadU16LE()
 	r.ReadBytes(p.Signature[:])
-	r.ReadBytes(p.StateSignature[:])
+	if p.stateRootEnabled {
+		r.ReadBytes(p.StateSignature[:])
+	}
 	p.InvocationScript = r.ReadVarBytes(1024)
 }
 
@@ -122,7 +138,9 @@ func (p *commitCompact) EncodeBinary(w *io.BinWriter) {
 	w.WriteB(p.ViewNumber)
 	w.WriteU16LE(p.ValidatorIndex)
 	w.WriteBytes(p.Signature[:])
-	w.WriteBytes(p.StateSignature[:])
+	if p.stateRootEnabled {
+		w.WriteBytes(p.StateSignature[:])
+	}
 	w.WriteVarBytes(p.InvocationScript)
 }
 
@@ -146,6 +164,8 @@ func (m *recoveryMessage) AddPayload(p payload.ConsensusPayload) {
 			Type:       prepareRequestType,
 			ViewNumber: p.ViewNumber(),
 			payload:    p.GetPrepareRequest().(*prepareRequest),
+
+			stateRootEnabled: m.stateRootEnabled,
 		}
 		h := p.Hash()
 		m.preparationHash = &h
@@ -172,6 +192,7 @@ func (m *recoveryMessage) AddPayload(p payload.ConsensusPayload) {
 		})
 	case payload.CommitType:
 		m.commitPayloads = append(m.commitPayloads, &commitCompact{
+			stateRootEnabled: m.stateRootEnabled,
 			ValidatorIndex:   p.ValidatorIndex(),
 			ViewNumber:       p.ViewNumber(),
 			Signature:        p.GetCommit().(*commit).signature,
@@ -254,7 +275,12 @@ func (m *recoveryMessage) GetCommits(p payload.ConsensusPayload, validators []cr
 	ps := make([]payload.ConsensusPayload, len(m.commitPayloads))
 
 	for i, c := range m.commitPayloads {
-		cc := fromPayload(commitType, p.(*Payload), &commit{signature: c.Signature, stateSig: c.StateSignature})
+		cc := fromPayload(commitType, p.(*Payload), &commit{
+			signature: c.Signature,
+			stateSig:  c.StateSignature,
+
+			stateRootEnabled: m.stateRootEnabled,
+		})
 		cc.SetValidatorIndex(c.ValidatorIndex)
 		cc.Witness.InvocationScript = c.InvocationScript
 		cc.Witness.VerificationScript = getVerificationScript(c.ValidatorIndex, validators)
@@ -294,6 +320,8 @@ func fromPayload(t messageType, recovery *Payload, p io.Serializable) *Payload {
 			Type:       t,
 			ViewNumber: recovery.message.ViewNumber,
 			payload:    p,
+
+			stateRootEnabled: recovery.stateRootEnabled,
 		},
 		version:  recovery.Version(),
 		prevHash: recovery.PrevHash(),

pkg/core/blockchain.go

@@ -231,8 +231,10 @@ func (bc *Blockchain) init() error {
 	}
 	bc.blockHeight = bHeight
 	bc.persistedHeight = bHeight
-	if err = bc.dao.InitMPT(bHeight); err != nil {
-		return errors.Wrapf(err, "can't init MPT at height %d", bHeight)
+	if bc.config.EnableStateRoot {
+		if err = bc.dao.InitMPT(bHeight); err != nil {
+			return errors.Wrapf(err, "can't init MPT at height %d", bHeight)
+		}
 	}
 
 	hashes, err := bc.dao.GetHeaderHashes()
@@ -558,12 +560,18 @@ func (bc *Blockchain) getSystemFeeAmount(h util.Uint256) uint32 {
 
 // GetStateProof returns proof of having key in the MPT with the specified root.
 func (bc *Blockchain) GetStateProof(root util.Uint256, key []byte) ([][]byte, error) {
+	if !bc.config.EnableStateRoot {
+		return nil, errors.New("state root feature is not enabled")
+	}
 	tr := mpt.NewTrie(mpt.NewHashNode(root), storage.NewMemCachedStore(bc.dao.Store))
 	return tr.GetProof(key)
 }
 
 // GetStateRoot returns state root for a given height.
 func (bc *Blockchain) GetStateRoot(height uint32) (*state.MPTRootState, error) {
+	if !bc.config.EnableStateRoot {
+		return nil, errors.New("state root feature is not enabled")
+	}
 	return bc.dao.GetStateRoot(height)
 }
 
@@ -835,24 +843,26 @@ func (bc *Blockchain) storeBlock(block *block.Block) error {
 		}
 	}
 
-	root := bc.dao.MPT.StateRoot()
-	var prevHash util.Uint256
-	if block.Index > 0 {
-		prev, err := bc.dao.GetStateRoot(block.Index - 1)
-		if err != nil {
-			return errors.WithMessagef(err, "can't get previous state root")
+	if bc.config.EnableStateRoot {
+		root := bc.dao.MPT.StateRoot()
+		var prevHash util.Uint256
+		if block.Index > 0 {
+			prev, err := bc.dao.GetStateRoot(block.Index - 1)
+			if err != nil {
+				return errors.WithMessagef(err, "can't get previous state root")
+			}
+			prevHash = hash.DoubleSha256(prev.GetSignedPart())
+		}
+		err := bc.AddStateRoot(&state.MPTRoot{
+			MPTRootBase: state.MPTRootBase{
+				Index:    block.Index,
+				PrevHash: prevHash,
+				Root:     root,
+			},
+		})
+		if err != nil {
+			return err
 		}
-		prevHash = hash.DoubleSha256(prev.GetSignedPart())
-	}
-	err := bc.AddStateRoot(&state.MPTRoot{
-		MPTRootBase: state.MPTRootBase{
-			Index:    block.Index,
-			PrevHash: prevHash,
-			Root:     root,
-		},
-	})
-	if err != nil {
-		return err
 	}
 
 	if bc.config.SaveStorageBatch {
@@ -860,12 +870,14 @@ func (bc *Blockchain) storeBlock(block *block.Block) error {
 	}
 
 	bc.lock.Lock()
-	_, err = cache.Persist()
+	_, err := cache.Persist()
 	if err != nil {
 		bc.lock.Unlock()
 		return err
 	}
-	bc.dao.MPT.Flush()
+	if bc.config.EnableStateRoot {
+		bc.dao.MPT.Flush()
+	}
 	// Every persist cycle we also compact our in-memory MPT.
 	persistedHeight := atomic.LoadUint32(&bc.persistedHeight)
 	if persistedHeight == block.Index-1 {
@@ -1784,6 +1796,10 @@ func (bc *Blockchain) StateHeight() uint32 {
 
 // AddStateRoot add new (possibly unverified) state root to the blockchain.
 func (bc *Blockchain) AddStateRoot(r *state.MPTRoot) error {
+	if !bc.config.EnableStateRoot {
+		bc.log.Warn("state root is being added but not enabled in config")
+		return nil
+	}
 	our, err := bc.GetStateRoot(r.Index)
 	if err == nil {
 		if our.Flag == state.Verified {

pkg/core/interops.go

@@ -52,6 +52,9 @@ func (ic *interopContext) SpawnVM() *vm.VM {
 	})
 	vm.RegisterInteropGetter(ic.getSystemInterop)
 	vm.RegisterInteropGetter(ic.getNeoInterop)
+	if ic.bc != nil && ic.bc.GetConfig().EnableStateRoot {
+		vm.RegisterInteropGetter(ic.getNeoxInterop)
+	}
 	return vm
 }
 
@@ -77,6 +80,12 @@ func (ic *interopContext) getNeoInterop(id uint32) *vm.InteropFuncPrice {
 	return ic.getInteropFromSlice(id, neoInterops)
 }
 
+// getNeoxInterop returns matching interop function from the NeoX extension
+// for a given id in the current context.
+func (ic *interopContext) getNeoxInterop(id uint32) *vm.InteropFuncPrice {
+	return ic.getInteropFromSlice(id, neoxInterops)
+}
+
 // getInteropFromSlice returns matching interop function from the given slice of
 // interop functions in the current context.
 func (ic *interopContext) getInteropFromSlice(id uint32, slice []interopedFunction) *vm.InteropFuncPrice {
@@ -166,8 +175,6 @@ var neoInterops = []interopedFunction{
 	{Name: "Neo.Contract.GetStorageContext", Func: (*interopContext).contractGetStorageContext, Price: 1},
 	{Name: "Neo.Contract.IsPayable", Func: (*interopContext).contractIsPayable, Price: 1},
 	{Name: "Neo.Contract.Migrate", Func: (*interopContext).contractMigrate, Price: 0},
-	{Name: "Neo.Cryptography.Secp256k1Recover", Func: (*interopContext).secp256k1Recover, Price: 100},
-	{Name: "Neo.Cryptography.Secp256r1Recover", Func: (*interopContext).secp256r1Recover, Price: 100},
 	{Name: "Neo.Enumerator.Concat", Func: (*interopContext).enumeratorConcat, Price: 1},
 	{Name: "Neo.Enumerator.Create", Func: (*interopContext).enumeratorCreate, Price: 1},
 	{Name: "Neo.Enumerator.Next", Func: (*interopContext).enumeratorNext, Price: 1},
@@ -278,6 +285,11 @@ var neoInterops = []interopedFunction{
 	{Name: "AntShares.Transaction.GetType", Func: (*interopContext).txGetType, Price: 1},
 }
 
+var neoxInterops = []interopedFunction{
+	{Name: "Neo.Cryptography.Secp256k1Recover", Func: (*interopContext).secp256k1Recover, Price: 100},
+	{Name: "Neo.Cryptography.Secp256r1Recover", Func: (*interopContext).secp256r1Recover, Price: 100},
+}
+
 // initIDinInteropsSlice initializes IDs from names in one given
 // interopedFunction slice and then sorts it.
 func initIDinInteropsSlice(iops []interopedFunction) {
@@ -293,4 +305,5 @@ func initIDinInteropsSlice(iops []interopedFunction) {
 func init() {
 	initIDinInteropsSlice(systemInterops)
 	initIDinInteropsSlice(neoInterops)
+	initIDinInteropsSlice(neoxInterops)
 }

pkg/io/binaryReader.go

@@ -8,9 +8,9 @@ import (
 	"reflect"
 )
 
-// maxArraySize is a maximums size of an array which can be decoded.
+// MaxArraySize is the maximum size of an array which can be decoded.
 // It is taken from https://github.com/neo-project/neo/blob/master/neo/IO/Helper.cs#L130
-const maxArraySize = 0x1000000
+const MaxArraySize = 0x1000000
 
 // BinReader is a convenient wrapper around a io.Reader and err object.
 // Used to simplify error handling when reading into a struct with many fields.
@@ -110,7 +110,7 @@ func (r *BinReader) ReadArray(t interface{}, maxSize ...int) {
 	elemType := sliceType.Elem()
 	isPtr := elemType.Kind() == reflect.Ptr
 
-	ms := maxArraySize
+	ms := MaxArraySize
 	if len(maxSize) != 0 {
 		ms = maxSize[0]
 	}
@@ -170,7 +170,7 @@ func (r *BinReader) ReadVarUint() uint64 {
 // ReadVarUInt() is used to determine how large that slice is
 func (r *BinReader) ReadVarBytes(maxSize ...int) []byte {
 	n := r.ReadVarUint()
-	ms := maxArraySize
+	ms := MaxArraySize
 	if len(maxSize) != 0 {
 		ms = maxSize[0]
 	}

pkg/network/server.go

@@ -602,6 +602,10 @@ func (s *Server) handleGetHeadersCmd(p Peer, gh *payload.GetBlocks) error {
 
 // handleGetRootsCmd processees `getroots` request.
 func (s *Server) handleGetRootsCmd(p Peer, gr *payload.GetStateRoots) error {
+	cfg := s.chain.GetConfig()
+	if !cfg.EnableStateRoot || gr.Start < cfg.StateRootEnableIndex {
+		return nil
+	}
 	count := gr.Count
 	if count > payload.MaxStateRootsAllowed {
 		count = payload.MaxStateRootsAllowed
@@ -621,7 +625,13 @@ func (s *Server) handleGetRootsCmd(p Peer, gr *payload.GetStateRoots) error {
 
 // handleStateRootsCmd processees `roots` request.
 func (s *Server) handleRootsCmd(p Peer, rs *payload.StateRoots) error {
+	if !s.chain.GetConfig().EnableStateRoot {
+		return nil
+	}
 	h := s.chain.StateHeight()
+	if h < s.chain.GetConfig().StateRootEnableIndex {
+		h = s.chain.GetConfig().StateRootEnableIndex
+	}
 	for i := range rs.Roots {
 		if rs.Roots[i].Index <= h {
 			continue
@@ -636,6 +646,13 @@ func (s *Server) handleRootsCmd(p Peer, rs *payload.StateRoots) error {
 func (s *Server) requestStateRoot(p Peer) error {
 	stateHeight := s.chain.StateHeight()
 	hdrHeight := s.chain.BlockHeight()
+	enableIndex := s.chain.GetConfig().StateRootEnableIndex
+	if hdrHeight < enableIndex {
+		return nil
+	}
+	if stateHeight < enableIndex {
+		stateHeight = enableIndex - 1
+	}
 	count := uint32(payload.MaxStateRootsAllowed)
 	if diff := hdrHeight - stateHeight; diff < count {
 		count = diff
@@ -652,6 +669,9 @@ func (s *Server) requestStateRoot(p Peer) error {
 
 // handleStateRootCmd processees `stateroot` request.
 func (s *Server) handleStateRootCmd(r *state.MPTRoot) error {
+	if !s.chain.GetConfig().EnableStateRoot {
+		return nil
+	}
 	// we ignore error, because there is nothing wrong if we already have this state root
 	err := s.chain.AddStateRoot(r)
 	if err == nil && !s.stateCache.Has(r.Hash()) {

pkg/network/tcp_peer.go

@@ -251,7 +251,7 @@ func (p *TCPPeer) StartProtocol() {
 			if p.LastBlockIndex() > p.server.chain.BlockHeight() {
 				err = p.server.requestBlocks(p)
 			}
-			if err == nil {
+			if err == nil && p.server.chain.GetConfig().EnableStateRoot {
 				err = p.server.requestStateRoot(p)
 			}
 			if err == nil {