core: add native policy contract

part of #904

pkg/core/blockchain.go

@@ -1088,9 +1088,8 @@ func (bc *Blockchain) CalculateClaimable(value int64, startHeight, endHeight uin
 }
 
 // FeePerByte returns transaction network fee per byte.
-// TODO: should be implemented as part of PolicyContract
 func (bc *Blockchain) FeePerByte() util.Fixed8 {
-	return util.Fixed8(1000)
+	return util.Fixed8(bc.contracts.Policy.GetFeePerByteInternal(bc.dao))
 }
 
 // GetMemPool returns the memory pool of the blockchain.
@@ -1101,8 +1100,9 @@ func (bc *Blockchain) GetMemPool() *mempool.Pool {
 // ApplyPolicyToTxSet applies configured policies to given transaction set. It
 // expects slice to be ordered by fee and returns a subslice of it.
 func (bc *Blockchain) ApplyPolicyToTxSet(txes []*transaction.Transaction) []*transaction.Transaction {
-	if bc.config.MaxTransactionsPerBlock != 0 && len(txes) > bc.config.MaxTransactionsPerBlock {
-		txes = txes[:bc.config.MaxTransactionsPerBlock]
+	maxTx := bc.contracts.Policy.GetMaxTransactionsPerBlockInternal(bc.dao)
+	if maxTx != 0 && len(txes) > int(maxTx) {
+		txes = txes[:maxTx]
 	}
 	return txes
 }
@@ -1203,6 +1203,11 @@ func (bc *Blockchain) PoolTx(t *transaction.Transaction) error {
 		return err
 	}
 	// Policying.
+	if ok, err := bc.contracts.Policy.CheckPolicy(bc.newInteropContext(trigger.Application, bc.dao, nil, t), t); err != nil {
+		return err
+	} else if !ok {
+		return ErrPolicy
+	}
 	if err := bc.memPool.Add(t, bc); err != nil {
 		switch err {
 		case mempool.ErrOOM:

pkg/core/helper_test.go

@@ -387,6 +387,17 @@ func addSender(txs ...*transaction.Transaction) error {
 	return nil
 }
 
+func addCosigners(txs ...*transaction.Transaction) {
+	for _, tx := range txs {
+		tx.Cosigners = []transaction.Cosigner{{
+			Account:          neoOwner,
+			Scopes:           transaction.CalledByEntry,
+			AllowedContracts: nil,
+			AllowedGroups:    nil,
+		}}
+	}
+}
+
 func signTx(bc *Blockchain, txs ...*transaction.Transaction) error {
 	validators, err := getValidators(bc.config)
 	if err != nil {

pkg/core/native/blocked_accounts.go

@@ -0,0 +1,53 @@
+package native
+
+import (
+	"github.com/nspcc-dev/neo-go/pkg/io"
+	"github.com/nspcc-dev/neo-go/pkg/util"
+	"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
+)
+
+// BlockedAccounts represents a slice of blocked accounts hashes.
+type BlockedAccounts []util.Uint160
+
+// Bytes returns serialized BlockedAccounts.
+func (ba *BlockedAccounts) Bytes() []byte {
+	w := io.NewBufBinWriter()
+	ba.EncodeBinary(w.BinWriter)
+	if w.Err != nil {
+		panic(w.Err)
+	}
+	return w.Bytes()
+}
+
+// EncodeBinary implements io.Serializable interface.
+func (ba *BlockedAccounts) EncodeBinary(w *io.BinWriter) {
+	w.WriteArray(*ba)
+}
+
+// BlockedAccountsFromBytes converts serialized BlockedAccounts to structure.
+func BlockedAccountsFromBytes(b []byte) (BlockedAccounts, error) {
+	ba := new(BlockedAccounts)
+	if len(b) == 0 {
+		return *ba, nil
+	}
+	r := io.NewBinReaderFromBuf(b)
+	ba.DecodeBinary(r)
+	if r.Err != nil {
+		return nil, r.Err
+	}
+	return *ba, nil
+}
+
+// DecodeBinary implements io.Serializable interface.
+func (ba *BlockedAccounts) DecodeBinary(r *io.BinReader) {
+	r.ReadArray(ba)
+}
+
+// ToStackItem converts BlockedAccounts to stackitem.Item
+func (ba *BlockedAccounts) ToStackItem() stackitem.Item {
+	result := make([]stackitem.Item, len(*ba))
+	for i, account := range *ba {
+		result[i] = stackitem.NewByteArray(account.BytesLE())
+	}
+	return stackitem.NewArray(result)
+}

pkg/core/native/blocked_accounts_test.go

@@ -0,0 +1,53 @@
+package native
+
+import (
+	"testing"
+
+	"github.com/nspcc-dev/neo-go/pkg/internal/testserdes"
+	"github.com/nspcc-dev/neo-go/pkg/util"
+	"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
+	"github.com/stretchr/testify/require"
+)
+
+func TestEncodeDecodeBinary(t *testing.T) {
+	expected := &BlockedAccounts{
+		util.Uint160{1, 2, 3},
+		util.Uint160{4, 5, 6},
+	}
+	actual := new(BlockedAccounts)
+	testserdes.EncodeDecodeBinary(t, expected, actual)
+
+	expected = &BlockedAccounts{}
+	actual = new(BlockedAccounts)
+	testserdes.EncodeDecodeBinary(t, expected, actual)
+}
+
+func TestBytesFromBytes(t *testing.T) {
+	expected := BlockedAccounts{
+		util.Uint160{1, 2, 3},
+		util.Uint160{4, 5, 6},
+	}
+	actual, err := BlockedAccountsFromBytes(expected.Bytes())
+	require.NoError(t, err)
+	require.Equal(t, expected, actual)
+
+	expected = BlockedAccounts{}
+	actual, err = BlockedAccountsFromBytes(expected.Bytes())
+	require.NoError(t, err)
+	require.Equal(t, expected, actual)
+}
+
+func TestToStackItem(t *testing.T) {
+	u1 := util.Uint160{1, 2, 3}
+	u2 := util.Uint160{4, 5, 6}
+	expected := BlockedAccounts{u1, u2}
+	actual := stackitem.NewArray([]stackitem.Item{
+		stackitem.NewByteArray(u1.BytesLE()),
+		stackitem.NewByteArray(u2.BytesLE()),
+	})
+	require.Equal(t, expected.ToStackItem(), actual)
+
+	expected = BlockedAccounts{}
+	actual = stackitem.NewArray([]stackitem.Item{})
+	require.Equal(t, expected.ToStackItem(), actual)
+}

pkg/core/native/contract.go

@@ -16,6 +16,7 @@ import (
 type Contracts struct {
 	NEO       *NEO
 	GAS       *GAS
+	Policy    *Policy
 	Contracts []interop.Contract
 	// persistScript is vm script which executes "onPersist" method of every native contract.
 	persistScript []byte
@@ -41,7 +42,7 @@ func (cs *Contracts) ByID(id uint32) interop.Contract {
 	return nil
 }
 
-// NewContracts returns new set of native contracts with new GAS and NEO
+// NewContracts returns new set of native contracts with new GAS, NEO and Policy
 // contracts.
 func NewContracts() *Contracts {
 	cs := new(Contracts)
@@ -55,6 +56,10 @@ func NewContracts() *Contracts {
 	cs.Contracts = append(cs.Contracts, gas)
 	cs.NEO = neo
 	cs.Contracts = append(cs.Contracts, neo)
+
+	policy := newPolicy()
+	cs.Policy = policy
+	cs.Contracts = append(cs.Contracts, policy)
 	return cs
 }
 

pkg/core/native/policy.go

@@ -0,0 +1,393 @@
+package native
+
+import (
+	"encoding/binary"
+	"math/big"
+	"sort"
+
+	"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/core/transaction"
+	"github.com/nspcc-dev/neo-go/pkg/network/payload"
+	"github.com/nspcc-dev/neo-go/pkg/smartcontract"
+	"github.com/nspcc-dev/neo-go/pkg/smartcontract/manifest"
+	"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
+	"github.com/pkg/errors"
+)
+
+const (
+	policySyscallName = "Neo.Native.Policy"
+	policyContractID  = -3
+
+	defaultMaxBlockSize            = 1024 * 256
+	defaultMaxTransactionsPerBlock = 512
+	defaultFeePerByte              = 1000
+)
+
+var (
+	// maxTransactionsPerBlockKey is a key used to store the maximum number of
+	// transactions allowed in block.
+	maxTransactionsPerBlockKey = []byte{23}
+	// feePerByteKey is a key used to store the minimum fee per byte for
+	// transaction.
+	feePerByteKey = []byte{10}
+	// blockedAccountsKey is a key used to store the list of blocked accounts.
+	blockedAccountsKey = []byte{15}
+	// maxBlockSizeKey is a key used to store the maximum block size value.
+	maxBlockSizeKey = []byte{16}
+)
+
+// Policy represents Policy native contract.
+type Policy struct {
+	interop.ContractMD
+}
+
+var _ interop.Contract = (*Policy)(nil)
+
+// newPolicy returns Policy native contract.
+func newPolicy() *Policy {
+	p := &Policy{ContractMD: *interop.NewContractMD(policySyscallName)}
+
+	p.ContractID = policyContractID
+	p.Manifest.Features |= smartcontract.HasStorage
+
+	desc := newDescriptor("getMaxTransactionsPerBlock", smartcontract.IntegerType)
+	md := newMethodAndPrice(p.getMaxTransactionsPerBlock, 1000000, smartcontract.NoneFlag)
+	p.AddMethod(md, desc, true)
+
+	desc = newDescriptor("getMaxBlockSize", smartcontract.IntegerType)
+	md = newMethodAndPrice(p.getMaxBlockSize, 1000000, smartcontract.NoneFlag)
+	p.AddMethod(md, desc, true)
+
+	desc = newDescriptor("getFeePerByte", smartcontract.IntegerType)
+	md = newMethodAndPrice(p.getFeePerByte, 1000000, smartcontract.NoneFlag)
+	p.AddMethod(md, desc, true)
+
+	desc = newDescriptor("getBlockedAccounts", smartcontract.ArrayType)
+	md = newMethodAndPrice(p.getBlockedAccounts, 1000000, smartcontract.NoneFlag)
+	p.AddMethod(md, desc, true)
+
+	desc = newDescriptor("setMaxBlockSize", smartcontract.BoolType,
+		manifest.NewParameter("value", smartcontract.IntegerType))
+	md = newMethodAndPrice(p.setMaxBlockSize, 3000000, smartcontract.NoneFlag)
+	p.AddMethod(md, desc, false)
+
+	desc = newDescriptor("setMaxTransactionsPerBlock", smartcontract.BoolType,
+		manifest.NewParameter("value", smartcontract.IntegerType))
+	md = newMethodAndPrice(p.setMaxTransactionsPerBlock, 3000000, smartcontract.NoneFlag)
+	p.AddMethod(md, desc, false)
+
+	desc = newDescriptor("setFeePerByte", smartcontract.BoolType,
+		manifest.NewParameter("value", smartcontract.IntegerType))
+	md = newMethodAndPrice(p.setFeePerByte, 3000000, smartcontract.NoneFlag)
+	p.AddMethod(md, desc, false)
+
+	desc = newDescriptor("blockAccount", smartcontract.BoolType,
+		manifest.NewParameter("account", smartcontract.Hash160Type))
+	md = newMethodAndPrice(p.blockAccount, 3000000, smartcontract.NoneFlag)
+	p.AddMethod(md, desc, false)
+
+	desc = newDescriptor("unblockAccount", smartcontract.BoolType,
+		manifest.NewParameter("account", smartcontract.Hash160Type))
+	md = newMethodAndPrice(p.unblockAccount, 3000000, smartcontract.NoneFlag)
+	p.AddMethod(md, desc, false)
+
+	desc = newDescriptor("onPersist", smartcontract.BoolType)
+	md = newMethodAndPrice(getOnPersistWrapper(p.OnPersist), 0, smartcontract.AllowModifyStates)
+	p.AddMethod(md, desc, false)
+	return p
+}
+
+// Metadata implements Contract interface.
+func (p *Policy) Metadata() *interop.ContractMD {
+	return &p.ContractMD
+}
+
+// Initialize initializes Policy native contract and implements Contract interface.
+func (p *Policy) Initialize(ic *interop.Context) error {
+	si := &state.StorageItem{
+		Value: make([]byte, 4, 8),
+	}
+	binary.LittleEndian.PutUint32(si.Value, defaultMaxBlockSize)
+	err := ic.DAO.PutStorageItem(p.ContractID, maxBlockSizeKey, si)
+	if err != nil {
+		return err
+	}
+
+	binary.LittleEndian.PutUint32(si.Value, defaultMaxTransactionsPerBlock)
+	err = ic.DAO.PutStorageItem(p.ContractID, maxTransactionsPerBlockKey, si)
+	if err != nil {
+		return err
+	}
+
+	si.Value = si.Value[:8]
+	binary.LittleEndian.PutUint64(si.Value, defaultFeePerByte)
+	err = ic.DAO.PutStorageItem(p.ContractID, feePerByteKey, si)
+	if err != nil {
+		return err
+	}
+
+	ba := new(BlockedAccounts)
+	si.Value = ba.Bytes()
+	err = ic.DAO.PutStorageItem(p.ContractID, blockedAccountsKey, si)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+// OnPersist implements Contract interface.
+func (p *Policy) OnPersist(ic *interop.Context) error {
+	return nil
+}
+
+// getMaxTransactionsPerBlock is Policy contract method and returns the upper
+// limit of transactions per block.
+func (p *Policy) getMaxTransactionsPerBlock(ic *interop.Context, _ []stackitem.Item) stackitem.Item {
+	return stackitem.NewBigInteger(big.NewInt(int64(p.GetMaxTransactionsPerBlockInternal(ic.DAO))))
+}
+
+// GetMaxTransactionsPerBlockInternal returns the upper limit of transactions per
+// block.
+func (p *Policy) GetMaxTransactionsPerBlockInternal(dao dao.DAO) uint32 {
+	return p.getUint32WithKey(dao, maxTransactionsPerBlockKey)
+}
+
+// getMaxBlockSize is Policy contract method and returns maximum block size.
+func (p *Policy) getMaxBlockSize(ic *interop.Context, _ []stackitem.Item) stackitem.Item {
+	return stackitem.NewBigInteger(big.NewInt(int64(p.getUint32WithKey(ic.DAO, maxBlockSizeKey))))
+}
+
+// getFeePerByte is Policy contract method and returns required transaction's fee
+// per byte.
+func (p *Policy) getFeePerByte(ic *interop.Context, _ []stackitem.Item) stackitem.Item {
+	return stackitem.NewBigInteger(big.NewInt(p.GetFeePerByteInternal(ic.DAO)))
+}
+
+// GetFeePerByteInternal returns required transaction's fee per byte.
+func (p *Policy) GetFeePerByteInternal(dao dao.DAO) int64 {
+	return p.getInt64WithKey(dao, feePerByteKey)
+}
+
+// getBlockedAccounts is Policy contract method and returns list of blocked
+// accounts hashes.
+func (p *Policy) getBlockedAccounts(ic *interop.Context, _ []stackitem.Item) stackitem.Item {
+	ba, err := p.GetBlockedAccountsInternal(ic.DAO)
+	if err != nil {
+		panic(err)
+	}
+	return ba.ToStackItem()
+}
+
+// GetBlockedAccountsInternal returns list of blocked accounts hashes.
+func (p *Policy) GetBlockedAccountsInternal(dao dao.DAO) (BlockedAccounts, error) {
+	si := dao.GetStorageItem(p.ContractID, blockedAccountsKey)
+	if si == nil {
+		return nil, errors.New("BlockedAccounts uninitialized")
+	}
+	ba, err := BlockedAccountsFromBytes(si.Value)
+	if err != nil {
+		return nil, err
+	}
+	return ba, nil
+}
+
+// setMaxTransactionsPerBlock is Policy contract method and  sets the upper limit
+// of transactions per block.
+func (p *Policy) setMaxTransactionsPerBlock(ic *interop.Context, args []stackitem.Item) stackitem.Item {
+	ok, err := p.checkValidators(ic)
+	if err != nil {
+		panic(err)
+	}
+	if !ok {
+		return stackitem.NewBool(false)
+	}
+	value := uint32(toBigInt(args[0]).Int64())
+	err = p.setUint32WithKey(ic.DAO, maxTransactionsPerBlockKey, value)
+	if err != nil {
+		panic(err)
+	}
+	return stackitem.NewBool(true)
+}
+
+// setMaxBlockSize is Policy contract method and sets maximum block size.
+func (p *Policy) setMaxBlockSize(ic *interop.Context, args []stackitem.Item) stackitem.Item {
+	ok, err := p.checkValidators(ic)
+	if err != nil {
+		panic(err)
+	}
+	if !ok {
+		return stackitem.NewBool(false)
+	}
+	value := uint32(toBigInt(args[0]).Int64())
+	if payload.MaxSize <= value {
+		return stackitem.NewBool(false)
+	}
+	err = p.setUint32WithKey(ic.DAO, maxBlockSizeKey, value)
+	if err != nil {
+		panic(err)
+	}
+	return stackitem.NewBool(true)
+}
+
+// setFeePerByte is Policy contract method and sets transaction's fee per byte.
+func (p *Policy) setFeePerByte(ic *interop.Context, args []stackitem.Item) stackitem.Item {
+	ok, err := p.checkValidators(ic)
+	if err != nil {
+		panic(err)
+	}
+	if !ok {
+		return stackitem.NewBool(false)
+	}
+	value := toBigInt(args[0]).Int64()
+	err = p.setInt64WithKey(ic.DAO, feePerByteKey, value)
+	if err != nil {
+		panic(err)
+	}
+	return stackitem.NewBool(true)
+}
+
+// blockAccount is Policy contract method and adds given account hash to the list
+// of blocked accounts.
+func (p *Policy) blockAccount(ic *interop.Context, args []stackitem.Item) stackitem.Item {
+	ok, err := p.checkValidators(ic)
+	if err != nil {
+		panic(err)
+	}
+	if !ok {
+		return stackitem.NewBool(false)
+	}
+	value := toUint160(args[0])
+	si := ic.DAO.GetStorageItem(p.ContractID, blockedAccountsKey)
+	if si == nil {
+		panic("BlockedAccounts uninitialized")
+	}
+	ba, err := BlockedAccountsFromBytes(si.Value)
+	if err != nil {
+		panic(err)
+	}
+	indexToInsert := sort.Search(len(ba), func(i int) bool {
+		return !ba[i].Less(value)
+	})
+	ba = append(ba, value)
+	if indexToInsert != len(ba)-1 && ba[indexToInsert].Equals(value) {
+		return stackitem.NewBool(false)
+	}
+	if len(ba) > 1 {
+		copy(ba[indexToInsert+1:], ba[indexToInsert:])
+		ba[indexToInsert] = value
+	}
+	err = ic.DAO.PutStorageItem(p.ContractID, blockedAccountsKey, &state.StorageItem{
+		Value: ba.Bytes(),
+	})
+	if err != nil {
+		panic(err)
+	}
+	return stackitem.NewBool(true)
+}
+
+// unblockAccount is Policy contract method and removes given account hash from
+// the list of blocked accounts.
+func (p *Policy) unblockAccount(ic *interop.Context, args []stackitem.Item) stackitem.Item {
+	ok, err := p.checkValidators(ic)
+	if err != nil {
+		panic(err)
+	}
+	if !ok {
+		return stackitem.NewBool(false)
+	}
+	value := toUint160(args[0])
+	si := ic.DAO.GetStorageItem(p.ContractID, blockedAccountsKey)
+	if si == nil {
+		panic("BlockedAccounts uninitialized")
+	}
+	ba, err := BlockedAccountsFromBytes(si.Value)
+	if err != nil {
+		panic(err)
+	}
+	indexToRemove := sort.Search(len(ba), func(i int) bool {
+		return !ba[i].Less(value)
+	})
+	if indexToRemove == len(ba) || !ba[indexToRemove].Equals(value) {
+		return stackitem.NewBool(false)
+	}
+	ba = append(ba[:indexToRemove], ba[indexToRemove+1:]...)
+	err = ic.DAO.PutStorageItem(p.ContractID, blockedAccountsKey, &state.StorageItem{
+		Value: ba.Bytes(),
+	})
+	if err != nil {
+		panic(err)
+	}
+	return stackitem.NewBool(true)
+}
+
+func (p *Policy) getUint32WithKey(dao dao.DAO, key []byte) uint32 {
+	si := dao.GetStorageItem(p.ContractID, key)
+	if si == nil {
+		return 0
+	}
+	return binary.LittleEndian.Uint32(si.Value)
+}
+
+func (p *Policy) setUint32WithKey(dao dao.DAO, key []byte, value uint32) error {
+	si := dao.GetStorageItem(p.ContractID, key)
+	binary.LittleEndian.PutUint32(si.Value, value)
+	err := dao.PutStorageItem(p.ContractID, key, si)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func (p *Policy) getInt64WithKey(dao dao.DAO, key []byte) int64 {
+	si := dao.GetStorageItem(p.ContractID, key)
+	if si == nil {
+		return 0
+	}
+	return int64(binary.LittleEndian.Uint64(si.Value))
+}
+
+func (p *Policy) setInt64WithKey(dao dao.DAO, key []byte, value int64) error {
+	si := dao.GetStorageItem(p.ContractID, key)
+	binary.LittleEndian.PutUint64(si.Value, uint64(value))
+	err := dao.PutStorageItem(p.ContractID, key, si)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func (p *Policy) checkValidators(ic *interop.Context) (bool, error) {
+	prevBlock, err := ic.Chain.GetBlock(ic.Block.PrevHash)
+	if err != nil {
+		return false, err
+	}
+	return runtime.CheckHashedWitness(ic, nep5ScriptHash{
+		callingScriptHash: p.Hash,
+		entryScriptHash:   p.Hash,
+		currentScriptHash: p.Hash,
+	}, prevBlock.NextConsensus)
+}
+
+// CheckPolicy checks whether transaction's script hashes for verifying are
+// included into blocked accounts list.
+func (p *Policy) CheckPolicy(ic *interop.Context, tx *transaction.Transaction) (bool, error) {
+	ba, err := p.GetBlockedAccountsInternal(ic.DAO)
+	if err != nil {
+		return false, err
+	}
+	scriptHashes, err := ic.Chain.GetScriptHashesForVerifying(tx)
+	if err != nil {
+		return false, err
+	}
+	for _, acc := range ba {
+		for _, hash := range scriptHashes {
+			if acc.Equals(hash) {
+				return false, nil
+			}
+		}
+	}
+	return true, nil
+}

pkg/core/native_policy_test.go

@@ -0,0 +1,260 @@
+package core
+
+import (
+	"math/big"
+	"sort"
+	"testing"
+
+	"github.com/nspcc-dev/neo-go/pkg/core/native"
+	"github.com/nspcc-dev/neo-go/pkg/core/state"
+	"github.com/nspcc-dev/neo-go/pkg/core/transaction"
+	"github.com/nspcc-dev/neo-go/pkg/encoding/bigint"
+	"github.com/nspcc-dev/neo-go/pkg/io"
+	"github.com/nspcc-dev/neo-go/pkg/smartcontract"
+	"github.com/nspcc-dev/neo-go/pkg/util"
+	"github.com/nspcc-dev/neo-go/pkg/vm/emit"
+	"github.com/stretchr/testify/require"
+)
+
+func TestMaxTransactionsPerBlock(t *testing.T) {
+	chain := newTestChain(t)
+	defer chain.Close()
+
+	t.Run("get, internal method", func(t *testing.T) {
+		n := chain.contracts.Policy.GetMaxTransactionsPerBlockInternal(chain.dao)
+		require.Equal(t, 512, int(n))
+	})
+
+	t.Run("get, contract method", func(t *testing.T) {
+		res, err := invokeNativePolicyMethod(chain, "getMaxTransactionsPerBlock")
+		require.NoError(t, err)
+		checkResult(t, res, smartcontract.Parameter{
+			Type:  smartcontract.IntegerType,
+			Value: 512,
+		})
+		require.NoError(t, chain.persist())
+	})
+
+	t.Run("set", func(t *testing.T) {
+		res, err := invokeNativePolicyMethod(chain, "setMaxTransactionsPerBlock", bigint.ToBytes(big.NewInt(1024)))
+		require.NoError(t, err)
+		checkResult(t, res, smartcontract.Parameter{
+			Type:  smartcontract.BoolType,
+			Value: true,
+		})
+		require.NoError(t, chain.persist())
+		n := chain.contracts.Policy.GetMaxTransactionsPerBlockInternal(chain.dao)
+		require.Equal(t, 1024, int(n))
+	})
+}
+
+func TestMaxBlockSize(t *testing.T) {
+	chain := newTestChain(t)
+	defer chain.Close()
+
+	t.Run("get", func(t *testing.T) {
+		res, err := invokeNativePolicyMethod(chain, "getMaxBlockSize")
+		require.NoError(t, err)
+		checkResult(t, res, smartcontract.Parameter{
+			Type:  smartcontract.IntegerType,
+			Value: 1024 * 256,
+		})
+		require.NoError(t, chain.persist())
+	})
+
+	t.Run("set", func(t *testing.T) {
+		res, err := invokeNativePolicyMethod(chain, "setMaxBlockSize", bigint.ToBytes(big.NewInt(102400)))
+		require.NoError(t, err)
+		checkResult(t, res, smartcontract.Parameter{
+			Type:  smartcontract.BoolType,
+			Value: true,
+		})
+		require.NoError(t, chain.persist())
+		res, err = invokeNativePolicyMethod(chain, "getMaxBlockSize")
+		require.NoError(t, err)
+		checkResult(t, res, smartcontract.Parameter{
+			Type:  smartcontract.IntegerType,
+			Value: 102400,
+		})
+		require.NoError(t, chain.persist())
+	})
+}
+
+func TestFeePerByte(t *testing.T) {
+	chain := newTestChain(t)
+	defer chain.Close()
+
+	t.Run("get, internal method", func(t *testing.T) {
+		n := chain.contracts.Policy.GetFeePerByteInternal(chain.dao)
+		require.Equal(t, 1000, int(n))
+	})
+
+	t.Run("get, contract method", func(t *testing.T) {
+		res, err := invokeNativePolicyMethod(chain, "getFeePerByte")
+		require.NoError(t, err)
+		checkResult(t, res, smartcontract.Parameter{
+			Type:  smartcontract.IntegerType,
+			Value: 1000,
+		})
+		require.NoError(t, chain.persist())
+	})
+
+	t.Run("set", func(t *testing.T) {
+		res, err := invokeNativePolicyMethod(chain, "setFeePerByte", bigint.ToBytes(big.NewInt(1024)))
+		require.NoError(t, err)
+		checkResult(t, res, smartcontract.Parameter{
+			Type:  smartcontract.BoolType,
+			Value: true,
+		})
+		require.NoError(t, chain.persist())
+		n := chain.contracts.Policy.GetFeePerByteInternal(chain.dao)
+		require.Equal(t, 1024, int(n))
+	})
+}
+
+func TestBlockedAccounts(t *testing.T) {
+	chain := newTestChain(t)
+	defer chain.Close()
+	account := util.Uint160{1, 2, 3}
+
+	t.Run("get, internal method", func(t *testing.T) {
+		accounts, err := chain.contracts.Policy.GetBlockedAccountsInternal(chain.dao)
+		require.NoError(t, err)
+		require.Equal(t, native.BlockedAccounts{}, accounts)
+	})
+
+	t.Run("get, contract method", func(t *testing.T) {
+		res, err := invokeNativePolicyMethod(chain, "getBlockedAccounts")
+		require.NoError(t, err)
+		checkResult(t, res, smartcontract.Parameter{
+			Type:  smartcontract.ArrayType,
+			Value: []smartcontract.Parameter{},
+		})
+		require.NoError(t, chain.persist())
+	})
+
+	t.Run("block-unblock account", func(t *testing.T) {
+		res, err := invokeNativePolicyMethod(chain, "blockAccount", account.BytesBE())
+		require.NoError(t, err)
+		checkResult(t, res, smartcontract.Parameter{
+			Type:  smartcontract.BoolType,
+			Value: true,
+		})
+
+		accounts, err := chain.contracts.Policy.GetBlockedAccountsInternal(chain.dao)
+		require.NoError(t, err)
+		require.Equal(t, native.BlockedAccounts{account}, accounts)
+		require.NoError(t, chain.persist())
+
+		res, err = invokeNativePolicyMethod(chain, "unblockAccount", account.BytesBE())
+		checkResult(t, res, smartcontract.Parameter{
+			Type:  smartcontract.BoolType,
+			Value: true,
+		})
+
+		accounts, err = chain.contracts.Policy.GetBlockedAccountsInternal(chain.dao)
+		require.NoError(t, err)
+		require.Equal(t, native.BlockedAccounts{}, accounts)
+		require.NoError(t, chain.persist())
+	})
+
+	t.Run("double-block", func(t *testing.T) {
+		// block
+		res, err := invokeNativePolicyMethod(chain, "blockAccount", account.BytesBE())
+		require.NoError(t, err)
+		checkResult(t, res, smartcontract.Parameter{
+			Type:  smartcontract.BoolType,
+			Value: true,
+		})
+		require.NoError(t, chain.persist())
+
+		// double-block should fail
+		res, err = invokeNativePolicyMethod(chain, "blockAccount", account.BytesBE())
+		require.NoError(t, err)
+		checkResult(t, res, smartcontract.Parameter{
+			Type:  smartcontract.BoolType,
+			Value: false,
+		})
+		require.NoError(t, chain.persist())
+
+		// unblock
+		res, err = invokeNativePolicyMethod(chain, "unblockAccount", account.BytesBE())
+		checkResult(t, res, smartcontract.Parameter{
+			Type:  smartcontract.BoolType,
+			Value: true,
+		})
+		require.NoError(t, chain.persist())
+
+		// unblock the same account should fail as we don't have it blocked
+		res, err = invokeNativePolicyMethod(chain, "unblockAccount", account.BytesBE())
+		checkResult(t, res, smartcontract.Parameter{
+			Type:  smartcontract.BoolType,
+			Value: false,
+		})
+		require.NoError(t, chain.persist())
+	})
+
+	t.Run("sorted", func(t *testing.T) {
+		accounts := []util.Uint160{
+			{2, 3, 4},
+			{4, 5, 6},
+			{3, 4, 5},
+			{1, 2, 3},
+		}
+		for _, acc := range accounts {
+			res, err := invokeNativePolicyMethod(chain, "blockAccount", acc.BytesBE())
+			require.NoError(t, err)
+			checkResult(t, res, smartcontract.Parameter{
+				Type:  smartcontract.BoolType,
+				Value: true,
+			})
+			require.NoError(t, chain.persist())
+		}
+
+		sort.Slice(accounts, func(i, j int) bool {
+			return accounts[i].Less(accounts[j])
+		})
+		actual, err := chain.contracts.Policy.GetBlockedAccountsInternal(chain.dao)
+		require.NoError(t, err)
+		require.Equal(t, native.BlockedAccounts(accounts), actual)
+	})
+}
+
+func invokeNativePolicyMethod(chain *Blockchain, method string, args ...interface{}) (*state.AppExecResult, error) {
+	w := io.NewBufBinWriter()
+	emit.AppCallWithOperationAndArgs(w.BinWriter, chain.contracts.Policy.Metadata().Hash, method, args...)
+	if w.Err != nil {
+		return nil, w.Err
+	}
+	script := w.Bytes()
+	tx := transaction.New(chain.GetConfig().Magic, script, 0)
+	validUntil := chain.blockHeight + 1
+	tx.ValidUntilBlock = validUntil
+	err := addSender(tx)
+	if err != nil {
+		return nil, err
+	}
+	addCosigners(tx)
+	err = signTx(chain, tx)
+	if err != nil {
+		return nil, err
+	}
+	b := chain.newBlock(tx)
+	err = chain.AddBlock(b)
+	if err != nil {
+		return nil, err
+	}
+
+	res, err := chain.GetAppExecResult(tx.Hash())
+	if err != nil {
+		return nil, err
+	}
+	return res, nil
+}
+
+func checkResult(t *testing.T, result *state.AppExecResult, expected smartcontract.Parameter) {
+	require.Equal(t, "HALT", result.VMState)
+	require.Equal(t, 1, len(result.Stack))
+	require.Equal(t, expected.Type, result.Stack[0].Type)
+	require.EqualValues(t, expected.Value, result.Stack[0].Value)
+}

pkg/network/compress.go

@@ -1,6 +1,7 @@
 package network
 
 import (
+	"github.com/nspcc-dev/neo-go/pkg/network/payload"
 	"github.com/pierrec/lz4"
 )
 
@@ -17,8 +18,8 @@ func compress(source []byte) ([]byte, error) {
 // decompress decompresses bytes using lz4.
 func decompress(source []byte) ([]byte, error) {
 	maxSize := len(source) * 255
-	if maxSize > PayloadMaxSize {
-		maxSize = PayloadMaxSize
+	if maxSize > payload.MaxSize {
+		maxSize = payload.MaxSize
 	}
 	dest := make([]byte, maxSize)
 	size, err := lz4.UncompressBlock(source, dest)

pkg/network/message.go

@@ -14,12 +14,8 @@ import (
 
 //go:generate stringer -type=CommandType
 
-const (
-	// PayloadMaxSize is maximum payload size in decompressed form.
-	PayloadMaxSize = 0x02000000
-	// CompressionMinSize is the lower bound to apply compression.
-	CompressionMinSize = 1024
-)
+// CompressionMinSize is the lower bound to apply compression.
+const CompressionMinSize = 1024
 
 // Message is the complete message send between nodes.
 type Message struct {
@@ -114,7 +110,7 @@ func (m *Message) Decode(br *io.BinReader) error {
 		}
 		return nil
 	}
-	if l > PayloadMaxSize {
+	if l > payload.MaxSize {
 		return errors.New("invalid payload size")
 	}
 	m.compressedPayload = make([]byte, l)

pkg/network/payload/payload.go

@@ -2,6 +2,9 @@ package payload
 
 import "github.com/nspcc-dev/neo-go/pkg/io"
 
+// MaxSize is maximum payload size in decompressed form.
+const MaxSize = 0x02000000
+
 // Payload is anything that can be binary encoded/decoded.
 type Payload interface {
 	io.Serializable