neoneo-go/pkg/core/blockchain.go
Roman Khimov 99bbad331d core: add issue tx processing
Count available asset quantity, match C# code.
2019-10-25 17:20:12 +03:00

1209 lines
35 KiB
Go

package core
import (
"bytes"
"context"
"fmt"
"math"
"sort"
"sync/atomic"
"time"
"github.com/CityOfZion/neo-go/config"
"github.com/CityOfZion/neo-go/pkg/core/storage"
"github.com/CityOfZion/neo-go/pkg/core/transaction"
"github.com/CityOfZion/neo-go/pkg/io"
"github.com/CityOfZion/neo-go/pkg/smartcontract"
"github.com/CityOfZion/neo-go/pkg/util"
"github.com/CityOfZion/neo-go/pkg/vm"
"github.com/pkg/errors"
log "github.com/sirupsen/logrus"
)
// Tuning parameters.
const (
headerBatchCount = 2000
version = "0.0.1"
// This one comes from C# code and it's different from the constant used
// when creating an asset with Neo.Asset.Create interop call. It looks
// like 2000000 is coming from the decrementInterval, but C# code doesn't
// contain any relationship between the two, so we should follow this
// behavior.
registeredAssetLifetime = 2 * 2000000
)
var (
genAmount = []int{8, 7, 6, 5, 4, 3, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}
decrementInterval = 2000000
persistInterval = 1 * time.Second
)
// Blockchain represents the blockchain.
type Blockchain struct {
config config.ProtocolConfiguration
// Persistent storage wrapped around with a write memory caching layer.
store *storage.MemCachedStore
// Current index/height of the highest block.
// Read access should always be called by BlockHeight().
// Write access should only happen in storeBlock().
blockHeight uint32
// Current persisted block count.
persistedHeight uint32
// Number of headers stored in the chain file.
storedHeaderCount uint32
// All operations on headerList must be called from an
// headersOp to be routine safe.
headerList *HeaderHashList
// Only for operating on the headerList.
headersOp chan headersOpFunc
headersOpDone chan struct{}
memPool MemPool
}
type headersOpFunc func(headerList *HeaderHashList)
// NewBlockchain returns a new blockchain object the will use the
// given Store as its underlying storage.
func NewBlockchain(s storage.Store, cfg config.ProtocolConfiguration) (*Blockchain, error) {
bc := &Blockchain{
config: cfg,
store: storage.NewMemCachedStore(s),
headersOp: make(chan headersOpFunc),
headersOpDone: make(chan struct{}),
memPool: NewMemPool(50000),
}
if err := bc.init(); err != nil {
return nil, err
}
return bc, nil
}
func (bc *Blockchain) init() error {
// If we could not find the version in the Store, we know that there is nothing stored.
ver, err := storage.Version(bc.store)
if err != nil {
log.Infof("no storage version found! creating genesis block")
if err = storage.PutVersion(bc.store, version); err != nil {
return err
}
genesisBlock, err := createGenesisBlock(bc.config)
if err != nil {
return err
}
bc.headerList = NewHeaderHashList(genesisBlock.Hash())
return bc.storeBlock(genesisBlock)
}
if ver != version {
return fmt.Errorf("storage version mismatch betweeen %s and %s", version, ver)
}
// At this point there was no version found in the storage which
// implies a creating fresh storage with the version specified
// and the genesis block as first block.
log.Infof("restoring blockchain with version: %s", version)
bHeight, err := storage.CurrentBlockHeight(bc.store)
if err != nil {
return err
}
bc.blockHeight = bHeight
bc.persistedHeight = bHeight
hashes, err := storage.HeaderHashes(bc.store)
if err != nil {
return err
}
bc.headerList = NewHeaderHashList(hashes...)
bc.storedHeaderCount = uint32(len(hashes))
currHeaderHeight, currHeaderHash, err := storage.CurrentHeaderHeight(bc.store)
if err != nil {
return err
}
// There is a high chance that the Node is stopped before the next
// batch of 2000 headers was stored. Via the currentHeaders stored we can sync
// that with stored blocks.
if currHeaderHeight > bc.storedHeaderCount {
hash := currHeaderHash
var targetHash util.Uint256
if bc.headerList.Len() > 0 {
targetHash = bc.headerList.Get(bc.headerList.Len() - 1)
} else {
genesisBlock, err := createGenesisBlock(bc.config)
if err != nil {
return err
}
targetHash = genesisBlock.Hash()
}
headers := make([]*Header, 0)
for hash != targetHash {
header, err := bc.GetHeader(hash)
if err != nil {
return fmt.Errorf("could not get header %s: %s", hash, err)
}
headers = append(headers, header)
hash = header.PrevHash
}
headerSliceReverse(headers)
for _, h := range headers {
if !h.Verify() {
return fmt.Errorf("bad header %d/%s in the storage", h.Index, h.Hash())
}
bc.headerList.Add(h.Hash())
}
}
return nil
}
// Run runs chain loop.
func (bc *Blockchain) Run(ctx context.Context) {
persistTimer := time.NewTimer(persistInterval)
defer func() {
persistTimer.Stop()
if err := bc.persist(); err != nil {
log.Warnf("failed to persist: %s", err)
}
if err := bc.store.Close(); err != nil {
log.Warnf("failed to close db: %s", err)
}
}()
for {
select {
case <-ctx.Done():
return
case op := <-bc.headersOp:
op(bc.headerList)
bc.headersOpDone <- struct{}{}
case <-persistTimer.C:
go func() {
err := bc.persist()
if err != nil {
log.Warnf("failed to persist blockchain: %s", err)
}
}()
persistTimer.Reset(persistInterval)
}
}
}
// AddBlock accepts successive block for the Blockchain, verifies it and
// stores internally. Eventually it will be persisted to the backing storage.
func (bc *Blockchain) AddBlock(block *Block) error {
expectedHeight := bc.BlockHeight() + 1
if expectedHeight != block.Index {
return fmt.Errorf("expected block %d, but passed block %d", expectedHeight, block.Index)
}
if bc.config.VerifyBlocks {
err := block.Verify()
if err == nil {
err = bc.VerifyBlock(block)
}
if err != nil {
return fmt.Errorf("block %s is invalid: %s", block.Hash().ReverseString(), err)
}
if bc.config.VerifyTransactions {
for _, tx := range block.Transactions {
err := bc.VerifyTx(tx, block)
if err != nil {
return fmt.Errorf("transaction %s failed to verify: %s", tx.Hash().ReverseString(), err)
}
}
}
}
headerLen := bc.headerListLen()
if int(block.Index) == headerLen {
err := bc.AddHeaders(block.Header())
if err != nil {
return err
}
}
return bc.storeBlock(block)
}
// AddHeaders processes the given headers and add them to the
// HeaderHashList.
func (bc *Blockchain) AddHeaders(headers ...*Header) (err error) {
var (
start = time.Now()
batch = bc.store.Batch()
)
bc.headersOp <- func(headerList *HeaderHashList) {
oldlen := headerList.Len()
for _, h := range headers {
if int(h.Index-1) >= headerList.Len() {
err = fmt.Errorf(
"height of received header %d is higher then the current header %d",
h.Index, headerList.Len(),
)
return
}
if int(h.Index) < headerList.Len() {
continue
}
if !h.Verify() {
err = fmt.Errorf("header %v is invalid", h)
return
}
if err = bc.processHeader(h, batch, headerList); err != nil {
return
}
}
if oldlen != headerList.Len() {
if err = bc.store.PutBatch(batch); err != nil {
return
}
log.WithFields(log.Fields{
"headerIndex": headerList.Len() - 1,
"blockHeight": bc.BlockHeight(),
"took": time.Since(start),
}).Debug("done processing headers")
}
}
<-bc.headersOpDone
return err
}
// processHeader processes the given header. Note that this is only thread safe
// if executed in headers operation.
func (bc *Blockchain) processHeader(h *Header, batch storage.Batch, headerList *HeaderHashList) error {
headerList.Add(h.Hash())
buf := io.NewBufBinWriter()
for int(h.Index)-headerBatchCount >= int(bc.storedHeaderCount) {
if err := headerList.Write(buf.BinWriter, int(bc.storedHeaderCount), headerBatchCount); err != nil {
return err
}
key := storage.AppendPrefixInt(storage.IXHeaderHashList, int(bc.storedHeaderCount))
batch.Put(key, buf.Bytes())
bc.storedHeaderCount += headerBatchCount
buf.Reset()
}
buf.Reset()
h.EncodeBinary(buf.BinWriter)
if buf.Err != nil {
return buf.Err
}
key := storage.AppendPrefix(storage.DataBlock, h.Hash().BytesReverse())
batch.Put(key, buf.Bytes())
batch.Put(storage.SYSCurrentHeader.Bytes(), hashAndIndexToBytes(h.Hash(), h.Index))
return nil
}
// TODO: storeBlock needs some more love, its implemented as in the original
// project. This for the sake of development speed and understanding of what
// is happening here, quite allot as you can see :). If things are wired together
// and all tests are in place, we can make a more optimized and cleaner implementation.
func (bc *Blockchain) storeBlock(block *Block) error {
var (
tmpStore = storage.NewMemCachedStore(bc.store)
unspentCoins = make(UnspentCoins)
spentCoins = make(SpentCoins)
accounts = make(Accounts)
assets = make(Assets)
contracts = make(Contracts)
)
if err := storeAsBlock(tmpStore, block, 0); err != nil {
return err
}
if err := storeAsCurrentBlock(tmpStore, block); err != nil {
return err
}
for _, tx := range block.Transactions {
if err := storeAsTransaction(tmpStore, tx, block.Index); err != nil {
return err
}
unspentCoins[tx.Hash()] = NewUnspentCoinState(len(tx.Outputs))
// Process TX outputs.
for _, output := range tx.Outputs {
account, err := accounts.getAndUpdate(bc.store, output.ScriptHash)
if err != nil {
return err
}
if _, ok := account.Balances[output.AssetID]; ok {
account.Balances[output.AssetID] += output.Amount
} else {
account.Balances[output.AssetID] = output.Amount
}
}
// Process TX inputs that are grouped by previous hash.
for prevHash, inputs := range tx.GroupInputsByPrevHash() {
prevTX, prevTXHeight, err := bc.GetTransaction(prevHash)
if err != nil {
return fmt.Errorf("could not find previous TX: %s", prevHash)
}
for _, input := range inputs {
unspent, err := unspentCoins.getAndUpdate(bc.store, input.PrevHash)
if err != nil {
return err
}
unspent.states[input.PrevIndex] = CoinStateSpent
prevTXOutput := prevTX.Outputs[input.PrevIndex]
account, err := accounts.getAndUpdate(bc.store, prevTXOutput.ScriptHash)
if err != nil {
return err
}
if prevTXOutput.AssetID.Equals(governingTokenTX().Hash()) {
spentCoin := NewSpentCoinState(input.PrevHash, prevTXHeight)
spentCoin.items[input.PrevIndex] = block.Index
spentCoins[input.PrevHash] = spentCoin
}
account.Balances[prevTXOutput.AssetID] -= prevTXOutput.Amount
}
}
// Process the underlying type of the TX.
switch t := tx.Data.(type) {
case *transaction.RegisterTX:
assets[tx.Hash()] = &AssetState{
ID: tx.Hash(),
AssetType: t.AssetType,
Name: t.Name,
Amount: t.Amount,
Precision: t.Precision,
Owner: t.Owner,
Admin: t.Admin,
Expiration: bc.BlockHeight() + registeredAssetLifetime,
}
case *transaction.IssueTX:
for _, res := range bc.GetTransactionResults(tx) {
if res.Amount < 0 {
var asset *AssetState
asset, ok := assets[res.AssetID]
if !ok {
asset = bc.GetAssetState(res.AssetID)
}
if asset == nil {
return fmt.Errorf("issue failed: no asset %s", res.AssetID)
}
asset.Available -= res.Amount
assets[res.AssetID] = asset
}
}
case *transaction.ClaimTX:
case *transaction.EnrollmentTX:
case *transaction.StateTX:
case *transaction.PublishTX:
var properties smartcontract.PropertyState
if t.NeedStorage {
properties |= smartcontract.HasStorage
}
contract := &ContractState{
Script: t.Script,
ParamList: t.ParamList,
ReturnType: t.ReturnType,
Properties: properties,
Name: t.Name,
CodeVersion: t.CodeVersion,
Author: t.Author,
Email: t.Email,
Description: t.Description,
}
contracts[contract.ScriptHash()] = contract
case *transaction.InvocationTX:
vm := vm.New()
vm.SetCheckedHash(tx.VerificationHash().Bytes())
vm.SetScriptGetter(func(hash util.Uint160) []byte {
cs := bc.GetContractState(hash)
if cs == nil {
return nil
}
return cs.Script
})
systemInterop := newInteropContext(0x10, bc, tmpStore, block, tx)
vm.RegisterInteropFuncs(systemInterop.getSystemInteropMap())
vm.RegisterInteropFuncs(systemInterop.getNeoInteropMap())
vm.LoadScript(t.Script)
err := vm.Run()
if !vm.HasFailed() {
_, err := systemInterop.mem.Persist()
if err != nil {
return errors.Wrap(err, "failed to persist invocation results")
}
} else {
log.WithFields(log.Fields{
"tx": tx.Hash().ReverseString(),
"block": block.Index,
"err": err,
}).Warn("contract invocation failed")
}
}
}
// Persist all to storage.
if err := accounts.commit(tmpStore); err != nil {
return err
}
if err := unspentCoins.commit(tmpStore); err != nil {
return err
}
if err := spentCoins.commit(tmpStore); err != nil {
return err
}
if err := assets.commit(tmpStore); err != nil {
return err
}
if err := contracts.commit(tmpStore); err != nil {
return err
}
if _, err := tmpStore.Persist(); err != nil {
return err
}
atomic.StoreUint32(&bc.blockHeight, block.Index)
for _, tx := range block.Transactions {
bc.memPool.Remove(tx.Hash())
}
return nil
}
// persist flushes current in-memory store contents to the persistent storage.
func (bc *Blockchain) persist() error {
var (
start = time.Now()
persisted int
err error
)
persisted, err = bc.store.Persist()
if err != nil {
return err
}
bHeight, err := storage.CurrentBlockHeight(bc.store)
if err != nil {
return err
}
oldHeight := atomic.SwapUint32(&bc.persistedHeight, bHeight)
diff := bHeight - oldHeight
storedHeaderHeight, _, err := storage.CurrentHeaderHeight(bc.store)
if err != nil {
return err
}
if persisted > 0 {
log.WithFields(log.Fields{
"persistedBlocks": diff,
"persistedKeys": persisted,
"headerHeight": storedHeaderHeight,
"blockHeight": bHeight,
"took": time.Since(start),
}).Info("blockchain persist completed")
}
return nil
}
func (bc *Blockchain) headerListLen() (n int) {
bc.headersOp <- func(headerList *HeaderHashList) {
n = headerList.Len()
}
<-bc.headersOpDone
return
}
// GetTransaction returns a TX and its height by the given hash.
func (bc *Blockchain) GetTransaction(hash util.Uint256) (*transaction.Transaction, uint32, error) {
if tx, ok := bc.memPool.TryGetValue(hash); ok {
return tx, 0, nil // the height is not actually defined for memPool transaction. Not sure if zero is a good number in this case.
}
return getTransactionFromStore(bc.store, hash)
}
// getTransactionFromStore returns Transaction and its height by the given hash
// if it exists in the store.
func getTransactionFromStore(s storage.Store, hash util.Uint256) (*transaction.Transaction, uint32, error) {
key := storage.AppendPrefix(storage.DataTransaction, hash.BytesReverse())
b, err := s.Get(key)
if err != nil {
return nil, 0, err
}
r := io.NewBinReaderFromBuf(b)
var height uint32
r.ReadLE(&height)
tx := &transaction.Transaction{}
tx.DecodeBinary(r)
if r.Err != nil {
return nil, 0, r.Err
}
return tx, height, nil
}
// GetStorageItem returns an item from storage.
func (bc *Blockchain) GetStorageItem(scripthash util.Uint160, key []byte) *StorageItem {
return getStorageItemFromStore(bc.store, scripthash, key)
}
// GetStorageItems returns all storage items for a given scripthash.
func (bc *Blockchain) GetStorageItems(hash util.Uint160) (map[string]*StorageItem, error) {
var siMap = make(map[string]*StorageItem)
var err error
saveToMap := func(k, v []byte) {
if err != nil {
return
}
r := io.NewBinReaderFromBuf(v)
si := &StorageItem{}
si.DecodeBinary(r)
if r.Err != nil {
err = r.Err
return
}
// Cut prefix and hash.
siMap[string(k[21:])] = si
}
bc.store.Seek(storage.AppendPrefix(storage.STStorage, hash.BytesReverse()), saveToMap)
if err != nil {
return nil, err
}
return siMap, nil
}
// GetBlock returns a Block by the given hash.
func (bc *Blockchain) GetBlock(hash util.Uint256) (*Block, error) {
block, err := getBlockFromStore(bc.store, hash)
if err != nil {
return nil, err
}
if len(block.Transactions) == 0 {
return nil, fmt.Errorf("only header is available")
}
for _, tx := range block.Transactions {
stx, _, err := bc.GetTransaction(tx.Hash())
if err != nil {
return nil, err
}
*tx = *stx
}
return block, nil
}
// getBlockFromStore returns Block by the given hash if it exists in the store.
func getBlockFromStore(s storage.Store, hash util.Uint256) (*Block, error) {
key := storage.AppendPrefix(storage.DataBlock, hash.BytesReverse())
b, err := s.Get(key)
if err != nil {
return nil, err
}
block, err := NewBlockFromTrimmedBytes(b)
if err != nil {
return nil, err
}
return block, err
}
// GetHeader returns data block header identified with the given hash value.
func (bc *Blockchain) GetHeader(hash util.Uint256) (*Header, error) {
return getHeaderFromStore(bc.store, hash)
}
// getHeaderFromStore returns Header by the given hash from the store.
func getHeaderFromStore(s storage.Store, hash util.Uint256) (*Header, error) {
block, err := getBlockFromStore(s, hash)
if err != nil {
return nil, err
}
return block.Header(), nil
}
// HasTransaction returns true if the blockchain contains he given
// transaction hash.
func (bc *Blockchain) HasTransaction(hash util.Uint256) bool {
return bc.memPool.ContainsKey(hash) ||
checkTransactionInStore(bc.store, hash)
}
// checkTransactionInStore returns true if the given store contains the given
// Transaction hash.
func checkTransactionInStore(s storage.Store, hash util.Uint256) bool {
key := storage.AppendPrefix(storage.DataTransaction, hash.BytesReverse())
if _, err := s.Get(key); err == nil {
return true
}
return false
}
// HasBlock returns true if the blockchain contains the given
// block hash.
func (bc *Blockchain) HasBlock(hash util.Uint256) bool {
if header, err := bc.GetHeader(hash); err == nil {
return header.Index <= bc.BlockHeight()
}
return false
}
// CurrentBlockHash returns the highest processed block hash.
func (bc *Blockchain) CurrentBlockHash() (hash util.Uint256) {
bc.headersOp <- func(headerList *HeaderHashList) {
hash = headerList.Get(int(bc.BlockHeight()))
}
<-bc.headersOpDone
return
}
// CurrentHeaderHash returns the hash of the latest known header.
func (bc *Blockchain) CurrentHeaderHash() (hash util.Uint256) {
bc.headersOp <- func(headerList *HeaderHashList) {
hash = headerList.Last()
}
<-bc.headersOpDone
return
}
// GetHeaderHash returns the hash from the headerList by its
// height/index.
func (bc *Blockchain) GetHeaderHash(i int) (hash util.Uint256) {
bc.headersOp <- func(headerList *HeaderHashList) {
hash = headerList.Get(i)
}
<-bc.headersOpDone
return
}
// BlockHeight returns the height/index of the highest block.
func (bc *Blockchain) BlockHeight() uint32 {
return atomic.LoadUint32(&bc.blockHeight)
}
// HeaderHeight returns the index/height of the highest header.
func (bc *Blockchain) HeaderHeight() uint32 {
return uint32(bc.headerListLen() - 1)
}
// GetAssetState returns asset state from its assetID.
func (bc *Blockchain) GetAssetState(assetID util.Uint256) *AssetState {
return getAssetStateFromStore(bc.store, assetID)
}
// getAssetStateFromStore returns given asset state as recorded in the given
// store.
func getAssetStateFromStore(s storage.Store, assetID util.Uint256) *AssetState {
key := storage.AppendPrefix(storage.STAsset, assetID.Bytes())
asEncoded, err := s.Get(key)
if err != nil {
return nil
}
var a AssetState
r := io.NewBinReaderFromBuf(asEncoded)
a.DecodeBinary(r)
if r.Err != nil || a.ID != assetID {
return nil
}
return &a
}
// GetContractState returns contract by its script hash.
func (bc *Blockchain) GetContractState(hash util.Uint160) *ContractState {
return getContractStateFromStore(bc.store, hash)
}
// getContractStateFromStore returns contract state as recorded in the given
// store by the given script hash.
func getContractStateFromStore(s storage.Store, hash util.Uint160) *ContractState {
key := storage.AppendPrefix(storage.STContract, hash.Bytes())
contractBytes, err := s.Get(key)
if err != nil {
return nil
}
var c ContractState
r := io.NewBinReaderFromBuf(contractBytes)
c.DecodeBinary(r)
if r.Err != nil || c.ScriptHash() != hash {
return nil
}
return &c
}
// GetAccountState returns the account state from its script hash.
func (bc *Blockchain) GetAccountState(scriptHash util.Uint160) *AccountState {
as, err := getAccountStateFromStore(bc.store, scriptHash)
if as == nil && err != storage.ErrKeyNotFound {
log.Warnf("failed to get account state: %s", err)
}
return as
}
// GetUnspentCoinState returns unspent coin state for given tx hash.
func (bc *Blockchain) GetUnspentCoinState(hash util.Uint256) *UnspentCoinState {
ucs, err := getUnspentCoinStateFromStore(bc.store, hash)
if ucs == nil && err != storage.ErrKeyNotFound {
log.Warnf("failed to get unspent coin state: %s", err)
}
return ucs
}
// GetConfig returns the config stored in the blockchain.
func (bc *Blockchain) GetConfig() config.ProtocolConfiguration {
return bc.config
}
// References returns a map with input coin reference (prevhash and index) as key
// and transaction output as value from a transaction t.
// @TODO: unfortunately we couldn't attach this method to the Transaction struct in the
// transaction package because of a import cycle problem. Perhaps we should think to re-design
// the code base to avoid this situation.
func (bc *Blockchain) References(t *transaction.Transaction) map[transaction.Input]*transaction.Output {
references := make(map[transaction.Input]*transaction.Output)
for prevHash, inputs := range t.GroupInputsByPrevHash() {
if tx, _, err := bc.GetTransaction(prevHash); err != nil {
tx = nil
} else if tx != nil {
for _, in := range inputs {
references[*in] = tx.Outputs[in.PrevIndex]
}
} else {
references = nil
}
}
return references
}
// FeePerByte returns network fee divided by the size of the transaction.
func (bc *Blockchain) FeePerByte(t *transaction.Transaction) util.Fixed8 {
return bc.NetworkFee(t).Div(int64(io.GetVarSize(t)))
}
// NetworkFee returns network fee.
func (bc *Blockchain) NetworkFee(t *transaction.Transaction) util.Fixed8 {
inputAmount := util.Fixed8FromInt64(0)
for _, txOutput := range bc.References(t) {
if txOutput.AssetID == utilityTokenTX().Hash() {
inputAmount.Add(txOutput.Amount)
}
}
outputAmount := util.Fixed8FromInt64(0)
for _, txOutput := range t.Outputs {
if txOutput.AssetID == utilityTokenTX().Hash() {
outputAmount.Add(txOutput.Amount)
}
}
return inputAmount.Sub(outputAmount).Sub(bc.SystemFee(t))
}
// SystemFee returns system fee.
func (bc *Blockchain) SystemFee(t *transaction.Transaction) util.Fixed8 {
return bc.GetConfig().SystemFee.TryGetValue(t.Type)
}
// IsLowPriority flags a transaction as low priority if the network fee is less than
// LowPriorityThreshold.
func (bc *Blockchain) IsLowPriority(t *transaction.Transaction) bool {
return bc.NetworkFee(t) < util.Fixed8FromFloat(bc.GetConfig().LowPriorityThreshold)
}
// GetMemPool returns the memory pool of the blockchain.
func (bc *Blockchain) GetMemPool() MemPool {
return bc.memPool
}
// VerifyBlock verifies block against its current state.
func (bc *Blockchain) VerifyBlock(block *Block) error {
prevHeader, err := bc.GetHeader(block.PrevHash)
if err != nil {
return errors.Wrap(err, "unable to get previous header")
}
if prevHeader.Index+1 != block.Index {
return errors.New("previous header index doesn't match")
}
if prevHeader.Timestamp >= block.Timestamp {
return errors.New("block is not newer than the previous one")
}
return bc.verifyBlockWitnesses(block, prevHeader)
}
// VerifyTx verifies whether a transaction is bonafide or not. Block parameter
// is used for easy interop access and can be omitted for transactions that are
// not yet added into any block.
// Golang implementation of Verify method in C# (https://github.com/neo-project/neo/blob/master/neo/Network/P2P/Payloads/Transaction.cs#L270).
func (bc *Blockchain) VerifyTx(t *transaction.Transaction, block *Block) error {
if io.GetVarSize(t) > transaction.MaxTransactionSize {
return errors.Errorf("invalid transaction size = %d. It shoud be less then MaxTransactionSize = %d", io.GetVarSize(t), transaction.MaxTransactionSize)
}
if ok := bc.verifyInputs(t); !ok {
return errors.New("invalid transaction's inputs")
}
if ok := bc.memPool.Verify(t); !ok {
return errors.New("invalid transaction due to conflicts with the memory pool")
}
if IsDoubleSpend(bc.store, t) {
return errors.New("invalid transaction caused by double spending")
}
if err := bc.verifyOutputs(t); err != nil {
return errors.Wrap(err, "wrong outputs")
}
if err := bc.verifyResults(t); err != nil {
return err
}
for _, a := range t.Attributes {
if a.Usage == transaction.ECDH02 || a.Usage == transaction.ECDH03 {
return errors.Errorf("invalid attribute's usage = %s ", a.Usage)
}
}
return bc.verifyTxWitnesses(t, block)
}
func (bc *Blockchain) verifyInputs(t *transaction.Transaction) bool {
for i := 1; i < len(t.Inputs); i++ {
for j := 0; j < i; j++ {
if t.Inputs[i].PrevHash == t.Inputs[j].PrevHash && t.Inputs[i].PrevIndex == t.Inputs[j].PrevIndex {
return false
}
}
}
return true
}
func (bc *Blockchain) verifyOutputs(t *transaction.Transaction) error {
for assetID, outputs := range t.GroupOutputByAssetID() {
assetState := bc.GetAssetState(assetID)
if assetState == nil {
return fmt.Errorf("no asset state for %s", assetID.ReverseString())
}
if assetState.Expiration < bc.blockHeight+1 && assetState.AssetType != transaction.GoverningToken && assetState.AssetType != transaction.UtilityToken {
return fmt.Errorf("asset %s expired", assetID.ReverseString())
}
for _, out := range outputs {
if int64(out.Amount)%int64(math.Pow10(8-int(assetState.Precision))) != 0 {
return fmt.Errorf("output is not compliant with %s asset precision", assetID.ReverseString())
}
}
}
return nil
}
func (bc *Blockchain) verifyResults(t *transaction.Transaction) error {
results := bc.GetTransactionResults(t)
if results == nil {
return errors.New("tx has no results")
}
var resultsDestroy []*transaction.Result
var resultsIssue []*transaction.Result
for _, re := range results {
if re.Amount.GreaterThan(util.Fixed8(0)) {
resultsDestroy = append(resultsDestroy, re)
}
if re.Amount.LessThan(util.Fixed8(0)) {
resultsIssue = append(resultsIssue, re)
}
}
if len(resultsDestroy) > 1 {
return errors.New("tx has more than 1 destroy output")
}
if len(resultsDestroy) == 1 && resultsDestroy[0].AssetID != utilityTokenTX().Hash() {
return errors.New("tx destroys non-utility token")
}
sysfee := bc.SystemFee(t)
if sysfee.GreaterThan(util.Fixed8(0)) {
if len(resultsDestroy) == 0 {
return fmt.Errorf("system requires to pay %s fee, but tx pays nothing", sysfee.String())
}
if resultsDestroy[0].Amount.LessThan(sysfee) {
return fmt.Errorf("system requires to pay %s fee, but tx pays %s only", sysfee.String(), resultsDestroy[0].Amount.String())
}
}
switch t.Type {
case transaction.MinerType, transaction.ClaimType:
for _, r := range resultsIssue {
if r.AssetID != utilityTokenTX().Hash() {
return errors.New("miner or claim tx issues non-utility tokens")
}
}
break
case transaction.IssueType:
for _, r := range resultsIssue {
if r.AssetID == utilityTokenTX().Hash() {
return errors.New("issue tx issues utility tokens")
}
}
break
default:
if len(resultsIssue) > 0 {
return errors.New("non issue/miner/claim tx issues tokens")
}
break
}
return nil
}
// GetTransactionResults returns the transaction results aggregate by assetID.
// Golang of GetTransationResults method in C# (https://github.com/neo-project/neo/blob/master/neo/Network/P2P/Payloads/Transaction.cs#L207)
func (bc *Blockchain) GetTransactionResults(t *transaction.Transaction) []*transaction.Result {
var tempResults []*transaction.Result
var results []*transaction.Result
tempGroupResult := make(map[util.Uint256]util.Fixed8)
references := bc.References(t)
if references == nil {
return nil
}
for _, output := range references {
tempResults = append(tempResults, &transaction.Result{
AssetID: output.AssetID,
Amount: output.Amount,
})
}
for _, output := range t.Outputs {
tempResults = append(tempResults, &transaction.Result{
AssetID: output.AssetID,
Amount: -output.Amount,
})
}
for _, r := range tempResults {
if amount, ok := tempGroupResult[r.AssetID]; ok {
tempGroupResult[r.AssetID] = amount.Add(r.Amount)
} else {
tempGroupResult[r.AssetID] = r.Amount
}
}
results = []*transaction.Result{} // this assignment is necessary. (Most of the time amount == 0 and results is the empty slice.)
for assetID, amount := range tempGroupResult {
if amount != util.Fixed8(0) {
results = append(results, &transaction.Result{
AssetID: assetID,
Amount: amount,
})
}
}
return results
}
// GetScriptHashesForVerifyingClaim returns all ScriptHashes of Claim transaction
// which has a different implementation from generic GetScriptHashesForVerifying.
func (bc *Blockchain) GetScriptHashesForVerifyingClaim(t *transaction.Transaction) ([]util.Uint160, error) {
// Avoiding duplicates.
hashmap := make(map[util.Uint160]bool)
claim := t.Data.(*transaction.ClaimTX)
clGroups := make(map[util.Uint256][]*transaction.Input)
for _, in := range claim.Claims {
clGroups[in.PrevHash] = append(clGroups[in.PrevHash], in)
}
for group, inputs := range clGroups {
refTx, _, err := bc.GetTransaction(group)
if err != nil {
return nil, err
}
for _, input := range inputs {
if len(refTx.Outputs) <= int(input.PrevIndex) {
return nil, fmt.Errorf("wrong PrevIndex reference")
}
hashmap[refTx.Outputs[input.PrevIndex].ScriptHash] = true
}
}
if len(hashmap) > 0 {
hashes := make([]util.Uint160, 0, len(hashmap))
for k := range hashmap {
hashes = append(hashes, k)
}
return hashes, nil
}
return nil, fmt.Errorf("no hashes found")
}
// GetScriptHashesForVerifying returns all the ScriptHashes of a transaction which will be use
// to verify whether the transaction is bonafide or not.
// Golang implementation of GetScriptHashesForVerifying method in C# (https://github.com/neo-project/neo/blob/master/neo/Network/P2P/Payloads/Transaction.cs#L190)
func (bc *Blockchain) GetScriptHashesForVerifying(t *transaction.Transaction) ([]util.Uint160, error) {
if t.Type == transaction.ClaimType {
return bc.GetScriptHashesForVerifyingClaim(t)
}
references := bc.References(t)
if references == nil {
return nil, errors.New("Invalid operation")
}
hashes := make(map[util.Uint160]bool)
for _, i := range t.Inputs {
h := references[*i].ScriptHash
if _, ok := hashes[h]; !ok {
hashes[h] = true
}
}
for _, a := range t.Attributes {
if a.Usage == transaction.Script {
h, err := util.Uint160DecodeBytes(a.Data)
if err != nil {
return nil, err
}
if _, ok := hashes[h]; !ok {
hashes[h] = true
}
}
}
for a, outputs := range t.GroupOutputByAssetID() {
as := bc.GetAssetState(a)
if as == nil {
return nil, errors.New("Invalid operation")
}
if as.AssetType&transaction.DutyFlag != 0 {
for _, o := range outputs {
h := o.ScriptHash
if _, ok := hashes[h]; !ok {
hashes[h] = true
}
}
}
}
// convert hashes to []util.Uint160
hashesResult := make([]util.Uint160, 0, len(hashes))
for h := range hashes {
hashesResult = append(hashesResult, h)
}
return hashesResult, nil
}
// verifyHashAgainstScript verifies given hash against the given witness.
func (bc *Blockchain) verifyHashAgainstScript(hash util.Uint160, witness *transaction.Witness, checkedHash util.Uint256, interopCtx *interopContext) error {
verification := witness.VerificationScript
if len(verification) == 0 {
bb := new(bytes.Buffer)
err := vm.EmitAppCall(bb, hash, false)
if err != nil {
return err
}
verification = bb.Bytes()
} else {
if h := witness.ScriptHash(); hash != h {
return errors.New("witness hash mismatch")
}
}
vm := vm.New()
vm.SetCheckedHash(checkedHash.Bytes())
vm.SetScriptGetter(func(hash util.Uint160) []byte {
cs := bc.GetContractState(hash)
if cs == nil {
return nil
}
return cs.Script
})
vm.RegisterInteropFuncs(interopCtx.getSystemInteropMap())
vm.RegisterInteropFuncs(interopCtx.getNeoInteropMap())
vm.LoadScript(verification)
vm.LoadScript(witness.InvocationScript)
err := vm.Run()
if vm.HasFailed() {
return errors.Errorf("vm failed to execute the script with error: %s", err)
}
resEl := vm.Estack().Pop()
if resEl != nil {
res, err := resEl.TryBool()
if err != nil {
return err
}
if !res {
return errors.Errorf("signature check failed")
}
} else {
return errors.Errorf("no result returned from the script")
}
return nil
}
// verifyTxWitnesses verifies the scripts (witnesses) that come with a given
// transaction. It can reorder them by ScriptHash, because that's required to
// match a slice of script hashes from the Blockchain. Block parameter
// is used for easy interop access and can be omitted for transactions that are
// not yet added into any block.
// Golang implementation of VerifyWitnesses method in C# (https://github.com/neo-project/neo/blob/master/neo/SmartContract/Helper.cs#L87).
// Unfortunately the IVerifiable interface could not be implemented because we can't move the References method in blockchain.go to the transaction.go file.
func (bc *Blockchain) verifyTxWitnesses(t *transaction.Transaction, block *Block) error {
hashes, err := bc.GetScriptHashesForVerifying(t)
if err != nil {
return err
}
witnesses := t.Scripts
if len(hashes) != len(witnesses) {
return errors.Errorf("expected len(hashes) == len(witnesses). got: %d != %d", len(hashes), len(witnesses))
}
sort.Slice(hashes, func(i, j int) bool { return hashes[i].Less(hashes[j]) })
sort.Slice(witnesses, func(i, j int) bool { return witnesses[i].ScriptHash().Less(witnesses[j].ScriptHash()) })
interopCtx := newInteropContext(0, bc, bc.store, block, t)
for i := 0; i < len(hashes); i++ {
err := bc.verifyHashAgainstScript(hashes[i], witnesses[i], t.VerificationHash(), interopCtx)
if err != nil {
numStr := fmt.Sprintf("witness #%d", i)
return errors.Wrap(err, numStr)
}
}
return nil
}
// verifyBlockWitnesses is a block-specific implementation of VerifyWitnesses logic.
func (bc *Blockchain) verifyBlockWitnesses(block *Block, prevHeader *Header) error {
var hash util.Uint160
if prevHeader == nil && block.PrevHash.Equals(util.Uint256{}) {
hash = block.Script.ScriptHash()
} else {
hash = prevHeader.NextConsensus
}
interopCtx := newInteropContext(0, bc, bc.store, nil, nil)
return bc.verifyHashAgainstScript(hash, block.Script, block.VerificationHash(), interopCtx)
}
func hashAndIndexToBytes(h util.Uint256, index uint32) []byte {
buf := io.NewBufBinWriter()
buf.WriteLE(h.BytesReverse())
buf.WriteLE(index)
return buf.Bytes()
}
func (bc *Blockchain) secondsPerBlock() int {
return bc.config.SecondsPerBlock
}