package core import ( "fmt" "math" "math/big" "sort" "sync" "sync/atomic" "time" "github.com/nspcc-dev/neo-go/pkg/config" "github.com/nspcc-dev/neo-go/pkg/core/block" "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/mempool" "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/storage" "github.com/nspcc-dev/neo-go/pkg/core/transaction" "github.com/nspcc-dev/neo-go/pkg/crypto/keys" "github.com/nspcc-dev/neo-go/pkg/io" "github.com/nspcc-dev/neo-go/pkg/smartcontract/trigger" "github.com/nspcc-dev/neo-go/pkg/util" "github.com/nspcc-dev/neo-go/pkg/vm" "github.com/nspcc-dev/neo-go/pkg/vm/emit" "github.com/pkg/errors" "go.uber.org/zap" ) // Tuning parameters. const ( headerBatchCount = 2000 version = "0.1.0" // 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 defaultMemPoolSize = 50000 ) var ( // ErrAlreadyExists is returned when trying to add some already existing // transaction into the pool (not specifying whether it exists in the // chain or mempool). ErrAlreadyExists = errors.New("already exists") // ErrOOM is returned when adding transaction to the memory pool because // it reached its full capacity. ErrOOM = errors.New("no space left in the memory pool") // ErrPolicy is returned on attempt to add transaction that doesn't // comply with node's configured policy into the mempool. ErrPolicy = errors.New("not allowed by policy") // ErrInvalidBlockIndex is returned when trying to add block with index // other than expected height of the blockchain. ErrInvalidBlockIndex error = errors.New("invalid block index") ) 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 // The only way chain state changes is by adding blocks, so we can't // allow concurrent block additions. It differs from the next lock in // that it's only for AddBlock method itself, the chain state is // protected by the lock below, but holding it during all of AddBlock // is too expensive (because the state only changes when persisting // change cache). addLock sync.Mutex // This lock ensures blockchain immutability for operations that need // that while performing their tasks. It's mostly used as a read lock // with the only writer being the block addition logic. lock sync.RWMutex // Data access object for CRUD operations around storage. dao *dao.Simple // 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 top Block wrapped in an atomic.Value for safe access. topBlock atomic.Value // Current persisted block count. persistedHeight uint32 // Number of headers stored in the chain file. storedHeaderCount uint32 generationAmount []int decrementInterval int // 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{} // Stop synchronization mechanisms. stopCh chan struct{} runToExitCh chan struct{} memPool mempool.Pool // This lock protects concurrent access to keyCache. keyCacheLock sync.RWMutex // cache for block verification keys. keyCache map[util.Uint160]map[string]*keys.PublicKey log *zap.Logger lastBatch *storage.MemBatch contracts native.Contracts } 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, log *zap.Logger) (*Blockchain, error) { if log == nil { return nil, errors.New("empty logger") } if cfg.MemPoolSize <= 0 { cfg.MemPoolSize = defaultMemPoolSize log.Info("mempool size is not set or wrong, setting default value", zap.Int("MemPoolSize", cfg.MemPoolSize)) } if cfg.MaxTransactionsPerBlock <= 0 { cfg.MaxTransactionsPerBlock = 0 log.Info("MaxTransactionsPerBlock is not set or wrong, setting default value (unlimited)", zap.Int("MaxTransactionsPerBlock", cfg.MaxTransactionsPerBlock)) } if cfg.MaxFreeTransactionsPerBlock <= 0 { cfg.MaxFreeTransactionsPerBlock = 0 log.Info("MaxFreeTransactionsPerBlock is not set or wrong, setting default value (unlimited)", zap.Int("MaxFreeTransactionsPerBlock", cfg.MaxFreeTransactionsPerBlock)) } if cfg.MaxFreeTransactionSize <= 0 { cfg.MaxFreeTransactionSize = 0 log.Info("MaxFreeTransactionSize is not set or wrong, setting default value (unlimited)", zap.Int("MaxFreeTransactionSize", cfg.MaxFreeTransactionSize)) } if cfg.FeePerExtraByte <= 0 { cfg.FeePerExtraByte = 0 log.Info("FeePerExtraByte is not set or wrong, setting default value", zap.Float64("FeePerExtraByte", cfg.FeePerExtraByte)) } bc := &Blockchain{ config: cfg, dao: dao.NewSimple(s), headersOp: make(chan headersOpFunc), headersOpDone: make(chan struct{}), stopCh: make(chan struct{}), runToExitCh: make(chan struct{}), memPool: mempool.NewMemPool(cfg.MemPoolSize), keyCache: make(map[util.Uint160]map[string]*keys.PublicKey), log: log, generationAmount: genAmount, decrementInterval: decrementInterval, contracts: *native.NewContracts(), } 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 := bc.dao.GetVersion() if err != nil { bc.log.Info("no storage version found! creating genesis block") if err = bc.dao.PutVersion(version); err != nil { return err } genesisBlock, err := createGenesisBlock(bc.config) if err != nil { return err } bc.headerList = NewHeaderHashList(genesisBlock.Hash()) err = bc.dao.PutCurrentHeader(hashAndIndexToBytes(genesisBlock.Hash(), genesisBlock.Index)) if err != nil { return err } 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. bc.log.Info("restoring blockchain", zap.String("version", version)) bHeight, err := bc.dao.GetCurrentBlockHeight() if err != nil { return err } bc.blockHeight = bHeight bc.persistedHeight = bHeight hashes, err := bc.dao.GetHeaderHashes() if err != nil { return err } bc.headerList = NewHeaderHashList(hashes...) bc.storedHeaderCount = uint32(len(hashes)) currHeaderHeight, currHeaderHash, err := bc.dao.GetCurrentHeaderHeight() if err != nil { return err } if bc.storedHeaderCount == 0 && currHeaderHeight == 0 { bc.headerList.Add(currHeaderHash) } // 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() bc.headerList.Add(targetHash) } headers := make([]*block.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() { persistTimer := time.NewTimer(persistInterval) defer func() { persistTimer.Stop() if err := bc.persist(); err != nil { bc.log.Warn("failed to persist", zap.Error(err)) } if err := bc.dao.Store.Close(); err != nil { bc.log.Warn("failed to close db", zap.Error(err)) } close(bc.runToExitCh) }() for { select { case <-bc.stopCh: return case op := <-bc.headersOp: op(bc.headerList) bc.headersOpDone <- struct{}{} case <-persistTimer.C: go func() { err := bc.persist() if err != nil { bc.log.Warn("failed to persist blockchain", zap.Error(err)) } persistTimer.Reset(persistInterval) }() } } } // Close stops Blockchain's internal loop, syncs changes to persistent storage // and closes it. The Blockchain is no longer functional after the call to Close. func (bc *Blockchain) Close() { close(bc.stopCh) <-bc.runToExitCh } // 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.Block) error { bc.addLock.Lock() defer bc.addLock.Unlock() expectedHeight := bc.BlockHeight() + 1 if expectedHeight != block.Index { return ErrInvalidBlockIndex } headerLen := bc.headerListLen() if int(block.Index) == headerLen { err := bc.addHeaders(bc.config.VerifyBlocks, block.Header()) if err != nil { return err } } if bc.config.VerifyBlocks { err := block.Verify() if err != nil { return fmt.Errorf("block %s is invalid: %s", block.Hash().StringLE(), 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().StringLE(), err) } } } } return bc.storeBlock(block) } // AddHeaders processes the given headers and add them to the // HeaderHashList. It expects headers to be sorted by index. func (bc *Blockchain) AddHeaders(headers ...*block.Header) error { return bc.addHeaders(bc.config.VerifyBlocks, headers...) } // addHeaders is an internal implementation of AddHeaders (`verify` parameter // tells it to verify or not verify given headers). func (bc *Blockchain) addHeaders(verify bool, headers ...*block.Header) (err error) { var ( start = time.Now() batch = bc.dao.Store.Batch() ) if len(headers) > 0 { var i int curHeight := bc.HeaderHeight() for i = range headers { if headers[i].Index > curHeight { break } } headers = headers[i:] } if len(headers) == 0 { return nil } else if verify { // Verify that the chain of the headers is consistent. var lastHeader *block.Header if lastHeader, err = bc.GetHeader(headers[0].PrevHash); err != nil { return fmt.Errorf("previous header was not found: %v", err) } for _, h := range headers { if err = bc.verifyHeader(h, lastHeader); err != nil { return } lastHeader = h } } 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() { updateHeaderHeightMetric(headerList.Len() - 1) if err = bc.dao.Store.PutBatch(batch); err != nil { return } bc.log.Debug("done processing headers", zap.Int("headerIndex", headerList.Len()-1), zap.Uint32("blockHeight", bc.BlockHeight()), zap.Duration("took", time.Since(start))) } } <-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 *block.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() buf.BinWriter.WriteU32LE(0) // sys fee is yet to be calculated h.EncodeBinary(buf.BinWriter) if buf.Err != nil { return buf.Err } key := storage.AppendPrefix(storage.DataBlock, h.Hash().BytesLE()) batch.Put(key, buf.Bytes()) batch.Put(storage.SYSCurrentHeader.Bytes(), hashAndIndexToBytes(h.Hash(), h.Index)) return nil } // getSystemFeeAmount returns sum of all system fees for blocks up to h. // and 0 if no such block exists. func (bc *Blockchain) getSystemFeeAmount(h util.Uint256) uint32 { _, sf, _ := bc.dao.GetBlock(h) return sf } // 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.Block) error { cache := dao.NewCached(bc.dao) fee := bc.getSystemFeeAmount(block.PrevHash) for _, tx := range block.Transactions { fee += uint32(tx.SystemFee.IntegralValue()) } if err := cache.StoreAsBlock(block, fee); err != nil { return err } if err := cache.StoreAsCurrentBlock(block); err != nil { return err } for _, tx := range block.Transactions { if err := cache.StoreAsTransaction(tx, block.Index); err != nil { return err } if err := cache.PutUnspentCoinState(tx.Hash(), state.NewUnspentCoin(block.Index, tx)); err != nil { return err } // Process TX outputs. if err := processOutputs(tx, cache); err != nil { return err } // Process TX inputs that are grouped by previous hash. for _, inputs := range transaction.GroupInputsByPrevHash(tx.Inputs) { prevHash := inputs[0].PrevHash unspent, err := cache.GetUnspentCoinState(prevHash) if err != nil { return err } for _, input := range inputs { if len(unspent.States) <= int(input.PrevIndex) { return fmt.Errorf("bad input: %s/%d", input.PrevHash.StringLE(), input.PrevIndex) } if unspent.States[input.PrevIndex].State&state.CoinSpent != 0 { return fmt.Errorf("double spend: %s/%d", input.PrevHash.StringLE(), input.PrevIndex) } unspent.States[input.PrevIndex].State |= state.CoinSpent unspent.States[input.PrevIndex].SpendHeight = block.Index prevTXOutput := &unspent.States[input.PrevIndex].Output account, err := cache.GetAccountStateOrNew(prevTXOutput.ScriptHash) if err != nil { return err } if prevTXOutput.AssetID.Equals(GoverningTokenID()) { err = account.Unclaimed.Put(&state.UnclaimedBalance{ Tx: input.PrevHash, Index: input.PrevIndex, Start: unspent.Height, End: block.Index, Value: prevTXOutput.Amount, }) if err != nil { return err } } balancesLen := len(account.Balances[prevTXOutput.AssetID]) if balancesLen <= 1 { delete(account.Balances, prevTXOutput.AssetID) } else { var index = -1 for i, balance := range account.Balances[prevTXOutput.AssetID] { if balance.Tx.Equals(input.PrevHash) && balance.Index == input.PrevIndex { index = i break } } if index >= 0 { last := balancesLen - 1 if last > index { account.Balances[prevTXOutput.AssetID][index] = account.Balances[prevTXOutput.AssetID][last] } account.Balances[prevTXOutput.AssetID] = account.Balances[prevTXOutput.AssetID][:last] } } if err = cache.PutAccountState(account); err != nil { return err } } if err = cache.PutUnspentCoinState(prevHash, unspent); err != nil { return err } } // Process the underlying type of the TX. switch t := tx.Data.(type) { case *transaction.RegisterTX: err := cache.PutAssetState(&state.Asset{ 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, }) if err != nil { return err } case *transaction.IssueTX: for _, res := range bc.GetTransactionResults(tx) { if res.Amount < 0 { asset, err := cache.GetAssetState(res.AssetID) if asset == nil || err != nil { return fmt.Errorf("issue failed: no asset %s or error %s", res.AssetID, err) } asset.Available -= res.Amount if err := cache.PutAssetState(asset); err != nil { return err } } } case *transaction.ClaimTX: // Remove claimed NEO from spent coins making it unavalaible for // additional claims. for _, input := range t.Claims { scs, err := cache.GetUnspentCoinState(input.PrevHash) if err == nil { if len(scs.States) <= int(input.PrevIndex) { err = errors.New("invalid claim index") } else if scs.States[input.PrevIndex].State&state.CoinClaimed != 0 { err = errors.New("double claim") } } if err != nil { // We can't really do anything about it // as it's a transaction in a signed block. bc.log.Warn("FALSE OR DOUBLE CLAIM", zap.String("PrevHash", input.PrevHash.StringLE()), zap.Uint16("PrevIndex", input.PrevIndex), zap.String("tx", tx.Hash().StringLE()), zap.Uint32("block", block.Index), ) // "Strict" mode. if bc.config.VerifyTransactions { return err } break } acc, err := cache.GetAccountState(scs.States[input.PrevIndex].ScriptHash) if err != nil { return err } scs.States[input.PrevIndex].State |= state.CoinClaimed if err = cache.PutUnspentCoinState(input.PrevHash, scs); err != nil { return err } changed := acc.Unclaimed.Remove(input.PrevHash, input.PrevIndex) if !changed { bc.log.Warn("no spent coin in the account", zap.String("tx", tx.Hash().StringLE()), zap.String("input", input.PrevHash.StringLE()), zap.String("account", acc.ScriptHash.String())) } else if err := cache.PutAccountState(acc); err != nil { return err } } case *transaction.InvocationTX: systemInterop := bc.newInteropContext(trigger.Application, cache, block, tx) v := SpawnVM(systemInterop) v.LoadScript(t.Script) v.SetPriceGetter(getPrice) if bc.config.FreeGasLimit > 0 { v.SetGasLimit(bc.config.FreeGasLimit + t.Gas) } err := v.Run() if !v.HasFailed() { _, err := systemInterop.DAO.Persist() if err != nil { return errors.Wrap(err, "failed to persist invocation results") } for _, note := range systemInterop.Notifications { arr, ok := note.Item.Value().([]vm.StackItem) if !ok || len(arr) != 4 { continue } op, ok := arr[0].Value().([]byte) if !ok || (string(op) != "transfer" && string(op) != "Transfer") { continue } var from []byte fromValue := arr[1].Value() // we don't have `from` set when we are minting tokens if fromValue != nil { from, ok = fromValue.([]byte) if !ok { continue } } var to []byte toValue := arr[2].Value() // we don't have `to` set when we are burning tokens if toValue != nil { to, ok = toValue.([]byte) if !ok { continue } } amount, ok := arr[3].Value().(*big.Int) if !ok { bs, ok := arr[3].Value().([]byte) if !ok { continue } amount = emit.BytesToInt(bs) } bc.processNEP5Transfer(cache, tx, block, note.ScriptHash, from, to, amount.Int64()) } } else { bc.log.Warn("contract invocation failed", zap.String("tx", tx.Hash().StringLE()), zap.Uint32("block", block.Index), zap.Error(err)) } aer := &state.AppExecResult{ TxHash: tx.Hash(), Trigger: trigger.Application, VMState: v.State(), GasConsumed: v.GasConsumed(), Stack: v.Estack().ToContractParameters(), Events: systemInterop.Notifications, } err = cache.PutAppExecResult(aer) if err != nil { return errors.Wrap(err, "failed to Store notifications") } } } bc.lock.Lock() defer bc.lock.Unlock() if bc.config.SaveStorageBatch { bc.lastBatch = cache.DAO.GetBatch() } for i := range bc.contracts.Contracts { systemInterop := bc.newInteropContext(trigger.Application, cache, block, nil) if err := bc.contracts.Contracts[i].OnPersist(systemInterop); err != nil { return err } } _, err := cache.Persist() if err != nil { return err } bc.topBlock.Store(block) atomic.StoreUint32(&bc.blockHeight, block.Index) updateBlockHeightMetric(block.Index) bc.memPool.RemoveStale(bc.isTxStillRelevant, bc) return nil } func parseUint160(addr []byte) util.Uint160 { if u, err := util.Uint160DecodeBytesBE(addr); err == nil { return u } return util.Uint160{} } func (bc *Blockchain) processNEP5Transfer(cache *dao.Cached, tx *transaction.Transaction, b *block.Block, sc util.Uint160, from, to []byte, amount int64) { toAddr := parseUint160(to) fromAddr := parseUint160(from) transfer := &state.NEP5Transfer{ Asset: sc, From: fromAddr, To: toAddr, Block: b.Index, Timestamp: b.Timestamp, Tx: tx.Hash(), } if !fromAddr.Equals(util.Uint160{}) { balances, err := cache.GetNEP5Balances(fromAddr) if err != nil { return } bs := balances.Trackers[sc] bs.Balance -= amount bs.LastUpdatedBlock = b.Index balances.Trackers[sc] = bs transfer.Amount = -amount isBig, err := cache.AppendNEP5Transfer(fromAddr, balances.NextTransferBatch, transfer) if err != nil { return } if isBig { balances.NextTransferBatch++ } if err := cache.PutNEP5Balances(fromAddr, balances); err != nil { return } } if !toAddr.Equals(util.Uint160{}) { balances, err := cache.GetNEP5Balances(toAddr) if err != nil { return } bs := balances.Trackers[sc] bs.Balance += amount bs.LastUpdatedBlock = b.Index balances.Trackers[sc] = bs transfer.Amount = amount isBig, err := cache.AppendNEP5Transfer(toAddr, balances.NextTransferBatch, transfer) if err != nil { return } if isBig { balances.NextTransferBatch++ } if err := cache.PutNEP5Balances(toAddr, balances); err != nil { return } } } // GetNEP5TransferLog returns NEP5 transfer log for the acc. func (bc *Blockchain) GetNEP5TransferLog(acc util.Uint160) *state.NEP5TransferLog { balances, err := bc.dao.GetNEP5Balances(acc) if err != nil { return nil } result := new(state.NEP5TransferLog) for i := uint32(0); i <= balances.NextTransferBatch; i++ { lg, err := bc.dao.GetNEP5TransferLog(acc, i) if err != nil { return nil } result.Raw = append(result.Raw, lg.Raw...) } return result } // GetNEP5Balances returns NEP5 balances for the acc. func (bc *Blockchain) GetNEP5Balances(acc util.Uint160) *state.NEP5Balances { bs, err := bc.dao.GetNEP5Balances(acc) if err != nil { return nil } return bs } // GetUtilityTokenBalance returns utility token (GAS) balance for the acc. func (bc *Blockchain) GetUtilityTokenBalance(acc util.Uint160) util.Fixed8 { return util.Fixed8FromInt64(bc.GetNEP5Balances(acc).Trackers[bc.contracts.GAS.Hash].Balance) } // LastBatch returns last persisted storage batch. func (bc *Blockchain) LastBatch() *storage.MemBatch { return bc.lastBatch } // processOutputs processes transaction outputs. func processOutputs(tx *transaction.Transaction, dao *dao.Cached) error { for index, output := range tx.Outputs { account, err := dao.GetAccountStateOrNew(output.ScriptHash) if err != nil { return err } account.Balances[output.AssetID] = append(account.Balances[output.AssetID], state.UnspentBalance{ Tx: tx.Hash(), Index: uint16(index), Value: output.Amount, }) if err = dao.PutAccountState(account); err != nil { return err } } 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.dao.Persist() if err != nil { return err } if persisted > 0 { bHeight, err := bc.dao.GetCurrentBlockHeight() if err != nil { return err } oldHeight := atomic.SwapUint32(&bc.persistedHeight, bHeight) diff := bHeight - oldHeight storedHeaderHeight, _, err := bc.dao.GetCurrentHeaderHeight() if err != nil { return err } bc.log.Info("blockchain persist completed", zap.Uint32("persistedBlocks", diff), zap.Int("persistedKeys", persisted), zap.Uint32("headerHeight", storedHeaderHeight), zap.Uint32("blockHeight", bHeight), zap.Duration("took", time.Since(start))) // update monitoring metrics. updatePersistedHeightMetric(bHeight) } 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 bc.dao.GetTransaction(hash) } // GetAppExecResult returns application execution result by the given // tx hash. func (bc *Blockchain) GetAppExecResult(hash util.Uint256) (*state.AppExecResult, error) { return bc.dao.GetAppExecResult(hash) } // GetStorageItem returns an item from storage. func (bc *Blockchain) GetStorageItem(scripthash util.Uint160, key []byte) *state.StorageItem { return bc.dao.GetStorageItem(scripthash, key) } // GetStorageItems returns all storage items for a given scripthash. func (bc *Blockchain) GetStorageItems(hash util.Uint160) (map[string]*state.StorageItem, error) { return bc.dao.GetStorageItems(hash) } // GetBlock returns a Block by the given hash. func (bc *Blockchain) GetBlock(hash util.Uint256) (*block.Block, error) { topBlock := bc.topBlock.Load() if topBlock != nil { if tb, ok := topBlock.(*block.Block); ok && tb.Hash().Equals(hash) { return tb, nil } } block, _, err := bc.dao.GetBlock(hash) if err != nil { return nil, err } for _, tx := range block.Transactions { stx, _, err := bc.dao.GetTransaction(tx.Hash()) if err != nil { return nil, err } *tx = *stx } return block, nil } // GetHeader returns data block header identified with the given hash value. func (bc *Blockchain) GetHeader(hash util.Uint256) (*block.Header, error) { topBlock := bc.topBlock.Load() if topBlock != nil { if tb, ok := topBlock.(*block.Block); ok && tb.Hash().Equals(hash) { return tb.Header(), nil } } block, _, err := bc.dao.GetBlock(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) || bc.dao.HasTransaction(hash) } // 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) *state.Asset { asset, err := bc.dao.GetAssetState(assetID) if asset == nil && err != storage.ErrKeyNotFound { bc.log.Warn("failed to get asset state", zap.Stringer("asset", assetID), zap.Error(err)) } return asset } // GetContractState returns contract by its script hash. func (bc *Blockchain) GetContractState(hash util.Uint160) *state.Contract { contract, err := bc.dao.GetContractState(hash) if contract == nil && err != storage.ErrKeyNotFound { bc.log.Warn("failed to get contract state", zap.Error(err)) } return contract } // GetAccountState returns the account state from its script hash. func (bc *Blockchain) GetAccountState(scriptHash util.Uint160) *state.Account { as, err := bc.dao.GetAccountState(scriptHash) if as == nil && err != storage.ErrKeyNotFound { bc.log.Warn("failed to get account state", zap.Error(err)) } return as } // GetUnspentCoinState returns unspent coin state for given tx hash. func (bc *Blockchain) GetUnspentCoinState(hash util.Uint256) *state.UnspentCoin { ucs, err := bc.dao.GetUnspentCoinState(hash) if ucs == nil && err != storage.ErrKeyNotFound { bc.log.Warn("failed to get unspent coin state", zap.Error(err)) } return ucs } // GetConfig returns the config stored in the blockchain. func (bc *Blockchain) GetConfig() config.ProtocolConfiguration { return bc.config } // CalculateClaimable calculates the amount of GAS which can be claimed for a transaction with value. // First return value is GAS generated between startHeight and endHeight. // Second return value is GAS returned from accumulated SystemFees between startHeight and endHeight. func (bc *Blockchain) CalculateClaimable(value util.Fixed8, startHeight, endHeight uint32) (util.Fixed8, util.Fixed8, error) { var amount util.Fixed8 di := uint32(bc.decrementInterval) ustart := startHeight / di if genSize := uint32(len(bc.generationAmount)); ustart < genSize { uend := endHeight / di iend := endHeight % di if uend >= genSize { uend = genSize - 1 iend = di } else if iend == 0 { uend-- iend = di } istart := startHeight % di for ustart < uend { amount += util.Fixed8(di-istart) * util.Fixed8(bc.generationAmount[ustart]) ustart++ istart = 0 } amount += util.Fixed8(iend-istart) * util.Fixed8(bc.generationAmount[ustart]) } if startHeight == 0 { startHeight++ } h := bc.GetHeaderHash(int(startHeight - 1)) feeStart := bc.getSystemFeeAmount(h) h = bc.GetHeaderHash(int(endHeight - 1)) feeEnd := bc.getSystemFeeAmount(h) sysFeeTotal := util.Fixed8(feeEnd - feeStart) ratio := value / 100000000 return amount * ratio, sysFeeTotal * ratio, nil } // References maps transaction's inputs into a slice of InOuts, effectively // joining each Input with the corresponding Output. // @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) ([]transaction.InOut, error) { return bc.references(t.Inputs) } // references is an internal implementation of References that operates directly // on a slice of Input. func (bc *Blockchain) references(ins []transaction.Input) ([]transaction.InOut, error) { references := make([]transaction.InOut, 0, len(ins)) for _, inputs := range transaction.GroupInputsByPrevHash(ins) { prevHash := inputs[0].PrevHash unspent, err := bc.dao.GetUnspentCoinState(prevHash) if err != nil { return nil, errors.New("bad input reference") } for _, in := range inputs { if int(in.PrevIndex) > len(unspent.States)-1 { return nil, errors.New("bad input reference") } references = append(references, transaction.InOut{In: *in, Out: unspent.States[in.PrevIndex].Output}) } } return references, nil } // 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) } // IsLowPriority checks given fee for being less than configured // LowPriorityThreshold. func (bc *Blockchain) IsLowPriority(fee util.Fixed8) bool { return fee < util.Fixed8FromFloat(bc.GetConfig().LowPriorityThreshold) } // GetMemPool returns the memory pool of the blockchain. func (bc *Blockchain) GetMemPool() *mempool.Pool { return &bc.memPool } // 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 []mempool.TxWithFee) []mempool.TxWithFee { if bc.config.MaxTransactionsPerBlock != 0 && len(txes) > bc.config.MaxTransactionsPerBlock { txes = txes[:bc.config.MaxTransactionsPerBlock] } maxFree := bc.config.MaxFreeTransactionsPerBlock if maxFree != 0 { lowStart := sort.Search(len(txes), func(i int) bool { return bc.IsLowPriority(txes[i].Fee) }) if lowStart+maxFree < len(txes) { txes = txes[:lowStart+maxFree] } } return txes } func (bc *Blockchain) verifyHeader(currHeader, prevHeader *block.Header) error { if prevHeader.Hash() != currHeader.PrevHash { return errors.New("previous header hash doesn't match") } if prevHeader.Index+1 != currHeader.Index { return errors.New("previous header index doesn't match") } if prevHeader.Timestamp >= currHeader.Timestamp { return errors.New("block is not newer than the previous one") } return bc.verifyHeaderWitnesses(currHeader, prevHeader) } // verifyTx verifies whether a transaction is bonafide or not. func (bc *Blockchain) verifyTx(t *transaction.Transaction, block *block.Block) error { height := bc.BlockHeight() if t.ValidUntilBlock <= height || t.ValidUntilBlock > height+transaction.MaxValidUntilBlockIncrement { return errors.Errorf("transaction has expired. ValidUntilBlock = %d, current height = %d", t.ValidUntilBlock, height) } balance := bc.GetUtilityTokenBalance(t.Sender) need := t.SystemFee.Add(t.NetworkFee) if balance.LessThan(need) { return errors.Errorf("insufficient funds: balance is %v, need: %v", balance, need) } size := io.GetVarSize(t) if size > transaction.MaxTransactionSize { return errors.Errorf("invalid transaction size = %d. It shoud be less then MaxTransactionSize = %d", io.GetVarSize(t), transaction.MaxTransactionSize) } needNetworkFee := util.Fixed8(int64(size) * int64(bc.FeePerByte())) netFee := t.NetworkFee.Sub(needNetworkFee) if netFee < 0 { return errors.Errorf("insufficient funds: net fee is %v, need %v", t.NetworkFee, needNetworkFee) } if transaction.HaveDuplicateInputs(t.Inputs) { return errors.New("invalid transaction's inputs") } if block == nil { if ok := bc.memPool.Verify(t, bc); !ok { return errors.New("invalid transaction due to conflicts with the memory pool") } } if bc.dao.IsDoubleSpend(t) { return errors.New("invalid transaction caused by double spending") } if err := bc.verifyOutputs(t); err != nil { return errors.Wrap(err, "wrong outputs") } refs, err := bc.References(t) if err != nil { return err } results := refsAndOutsToResults(refs, t.Outputs) if err := bc.verifyResults(t, results); 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) } } switch t.Type { case transaction.ClaimType: claim := t.Data.(*transaction.ClaimTX) if transaction.HaveDuplicateInputs(claim.Claims) { return errors.New("duplicate claims") } if bc.dao.IsDoubleClaim(claim) { return errors.New("double claim") } if err := bc.verifyClaims(t, results); err != nil { return err } case transaction.InvocationType: inv := t.Data.(*transaction.InvocationTX) if inv.Gas.FractionalValue() != 0 { return errors.New("invocation gas can only be integer") } } return bc.verifyTxWitnesses(t, block) } func (bc *Blockchain) verifyClaims(tx *transaction.Transaction, results []*transaction.Result) (err error) { t := tx.Data.(*transaction.ClaimTX) var result *transaction.Result for i := range results { if results[i].AssetID == UtilityTokenID() { result = results[i] break } } if result == nil || result.Amount.GreaterThan(0) { return errors.New("invalid output in claim tx") } bonus, err := bc.calculateBonus(t.Claims) if err == nil && bonus != -result.Amount { return fmt.Errorf("wrong bonus calculated in claim tx: %s != %s", bonus.String(), (-result.Amount).String()) } return err } func (bc *Blockchain) calculateBonus(claims []transaction.Input) (util.Fixed8, error) { unclaimed := []*spentCoin{} inputs := transaction.GroupInputsByPrevHash(claims) for _, group := range inputs { h := group[0].PrevHash unspent, err := bc.dao.GetUnspentCoinState(h) if err != nil { return 0, err } for _, c := range group { if len(unspent.States) <= int(c.PrevIndex) { return 0, fmt.Errorf("can't find spent coins for %s (%d)", c.PrevHash.StringLE(), c.PrevIndex) } if unspent.States[c.PrevIndex].State&state.CoinSpent == 0 { return 0, fmt.Errorf("not spent yet: %s/%d", c.PrevHash.StringLE(), c.PrevIndex) } if unspent.States[c.PrevIndex].State&state.CoinClaimed != 0 { return 0, fmt.Errorf("already claimed: %s/%d", c.PrevHash.StringLE(), c.PrevIndex) } unclaimed = append(unclaimed, &spentCoin{ Output: &unspent.States[c.PrevIndex].Output, StartHeight: unspent.Height, EndHeight: unspent.States[c.PrevIndex].SpendHeight, }) } } return bc.calculateBonusInternal(unclaimed) } func (bc *Blockchain) calculateBonusInternal(scs []*spentCoin) (util.Fixed8, error) { var claimed util.Fixed8 for _, sc := range scs { gen, sys, err := bc.CalculateClaimable(sc.Output.Amount, sc.StartHeight, sc.EndHeight) if err != nil { return 0, err } claimed += gen + sys } return claimed, nil } // isTxStillRelevant is a callback for mempool transaction filtering after the // new block addition. It returns false for transactions already present in the // chain (added by the new block), transactions using some inputs that are // already used (double spends) and does witness reverification for non-standard // contracts. It operates under the assumption that full transaction verification // was already done so we don't need to check basic things like size, input/output // correctness, etc. func (bc *Blockchain) isTxStillRelevant(t *transaction.Transaction) bool { var recheckWitness bool if bc.dao.HasTransaction(t.Hash()) { return false } if bc.dao.IsDoubleSpend(t) { return false } if t.Type == transaction.ClaimType { claim := t.Data.(*transaction.ClaimTX) if bc.dao.IsDoubleClaim(claim) { return false } } for i := range t.Scripts { if !vm.IsStandardContract(t.Scripts[i].VerificationScript) { recheckWitness = true break } } if recheckWitness { return bc.verifyTxWitnesses(t, nil) == nil } return true } // 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.Block) error { bc.lock.RLock() defer bc.lock.RUnlock() return bc.verifyTx(t, block) } // PoolTx verifies and tries to add given transaction into the mempool. func (bc *Blockchain) PoolTx(t *transaction.Transaction) error { bc.lock.RLock() defer bc.lock.RUnlock() if bc.HasTransaction(t.Hash()) { return ErrAlreadyExists } if err := bc.verifyTx(t, nil); err != nil { return err } // Policying. if t.Type != transaction.ClaimType { txSize := io.GetVarSize(t) maxFree := bc.config.MaxFreeTransactionSize if maxFree != 0 && txSize > maxFree { if bc.IsLowPriority(t.NetworkFee) || t.NetworkFee < util.Fixed8FromFloat(bc.config.FeePerExtraByte)*util.Fixed8(txSize-maxFree) { return ErrPolicy } } } if err := bc.memPool.Add(t, bc); err != nil { switch err { case mempool.ErrOOM: return ErrOOM case mempool.ErrConflict: return ErrAlreadyExists default: return err } } return nil } 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.StringLE()) } if assetState.Expiration < bc.blockHeight+1 && assetState.AssetType != transaction.GoverningToken && assetState.AssetType != transaction.UtilityToken { return fmt.Errorf("asset %s expired", assetID.StringLE()) } 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.StringLE()) } } } return nil } func (bc *Blockchain) verifyResults(t *transaction.Transaction, results []*transaction.Result) error { 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 != UtilityTokenID() { return errors.New("tx destroys non-utility token") } sysfee := t.SystemFee 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.ClaimType: for _, r := range resultsIssue { if r.AssetID != UtilityTokenID() { return errors.New("miner or claim tx issues non-utility tokens") } } break case transaction.IssueType: for _, r := range resultsIssue { if r.AssetID == UtilityTokenID() { return errors.New("issue tx issues utility tokens") } asset, err := bc.dao.GetAssetState(r.AssetID) if asset == nil || err != nil { return errors.New("invalid asset in issue tx") } if asset.Available < r.Amount { return errors.New("trying to issue more than available") } } 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 { references, err := bc.References(t) if err != nil { return nil } return refsAndOutsToResults(references, t.Outputs) } // mapReferencesToResults returns cumulative results of transaction based in its // references and outputs. func refsAndOutsToResults(references []transaction.InOut, outputs []transaction.Output) []*transaction.Result { var results []*transaction.Result tempResult := make(map[util.Uint256]util.Fixed8) for _, inout := range references { c := tempResult[inout.Out.AssetID] tempResult[inout.Out.AssetID] = c.Add(inout.Out.Amount) } for _, output := range outputs { c := tempResult[output.AssetID] tempResult[output.AssetID] = c.Sub(output.Amount) } results = []*transaction.Result{} // this assignment is necessary. (Most of the time amount == 0 and results is the empty slice.) for assetID, amount := range tempResult { if amount != util.Fixed8(0) { results = append(results, &transaction.Result{ AssetID: assetID, Amount: amount, }) } } return results } //GetStandByValidators returns validators from the configuration. func (bc *Blockchain) GetStandByValidators() (keys.PublicKeys, error) { return getValidators(bc.config) } // GetValidators returns next block validators. func (bc *Blockchain) GetValidators() ([]*keys.PublicKey, error) { return bc.contracts.NEO.GetNextBlockValidatorsInternal(bc, bc.dao) } // GetEnrollments returns all registered validators. func (bc *Blockchain) GetEnrollments() ([]state.Validator, error) { return bc.contracts.NEO.GetRegisteredValidators(bc.dao) } // 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) { references, err := bc.References(t) if err != nil { return nil, err } hashes := make(map[util.Uint160]bool) for i := range references { hashes[references[i].Out.ScriptHash] = 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 } } } } hashes[t.Sender] = true for _, c := range t.Cosigners { hashes[c.Account] = true } switch t.Type { case transaction.ClaimType: claim := t.Data.(*transaction.ClaimTX) refs, err := bc.references(claim.Claims) if err != nil { return nil, err } for i := range refs { hashes[refs[i].Out.ScriptHash] = true } case transaction.IssueType: for _, res := range refsAndOutsToResults(references, t.Outputs) { if res.Amount < 0 { asset, err := bc.dao.GetAssetState(res.AssetID) if asset == nil || err != nil { return nil, errors.New("invalid asset in issue tx") } hashes[asset.Issuer] = true } } case transaction.RegisterType: reg := t.Data.(*transaction.RegisterTX) hashes[reg.Owner.GetScriptHash()] = true } // convert hashes to []util.Uint160 hashesResult := make([]util.Uint160, 0, len(hashes)) for h := range hashes { hashesResult = append(hashesResult, h) } return hashesResult, nil } // GetTestVM returns a VM and a Store setup for a test run of some sort of code. func (bc *Blockchain) GetTestVM() *vm.VM { systemInterop := bc.newInteropContext(trigger.Application, bc.dao, nil, nil) vm := SpawnVM(systemInterop) vm.SetPriceGetter(getPrice) return vm } // ScriptFromWitness returns verification script for provided witness. // If hash is not equal to the witness script hash, error is returned. func ScriptFromWitness(hash util.Uint160, witness *transaction.Witness) ([]byte, error) { verification := witness.VerificationScript if len(verification) == 0 { bb := io.NewBufBinWriter() emit.AppCall(bb.BinWriter, hash) verification = bb.Bytes() } else if h := witness.ScriptHash(); hash != h { return nil, errors.New("witness hash mismatch") } return verification, nil } // verifyHashAgainstScript verifies given hash against the given witness. func (bc *Blockchain) verifyHashAgainstScript(hash util.Uint160, witness *transaction.Witness, interopCtx *interop.Context, useKeys bool) error { verification, err := ScriptFromWitness(hash, witness) if err != nil { return err } vm := SpawnVM(interopCtx) vm.LoadScript(verification) vm.LoadScript(witness.InvocationScript) if useKeys { bc.keyCacheLock.RLock() if bc.keyCache[hash] != nil { vm.SetPublicKeys(bc.keyCache[hash]) } bc.keyCacheLock.RUnlock() } 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 { if !resEl.Bool() { return errors.Errorf("signature check failed") } if useKeys { bc.keyCacheLock.RLock() _, ok := bc.keyCache[hash] bc.keyCacheLock.RUnlock() if !ok { bc.keyCacheLock.Lock() bc.keyCache[hash] = vm.GetPublicKeys() bc.keyCacheLock.Unlock() } } } 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.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 := bc.newInteropContext(trigger.Verification, bc.dao, block, t) for i := 0; i < len(hashes); i++ { err := bc.verifyHashAgainstScript(hashes[i], &witnesses[i], interopCtx, false) if err != nil { numStr := fmt.Sprintf("witness #%d", i) return errors.Wrap(err, numStr) } } return nil } // verifyHeaderWitnesses is a block-specific implementation of VerifyWitnesses logic. func (bc *Blockchain) verifyHeaderWitnesses(currHeader, prevHeader *block.Header) error { var hash util.Uint160 if prevHeader == nil && currHeader.PrevHash.Equals(util.Uint256{}) { hash = currHeader.Script.ScriptHash() } else { hash = prevHeader.NextConsensus } interopCtx := bc.newInteropContext(trigger.Verification, bc.dao, nil, nil) interopCtx.Container = currHeader return bc.verifyHashAgainstScript(hash, &currHeader.Script, interopCtx, true) } // GoverningTokenHash returns the governing token (NEO) native contract hash. func (bc *Blockchain) GoverningTokenHash() util.Uint160 { return bc.contracts.NEO.Hash } // UtilityTokenHash returns the utility token (GAS) native contract hash. func (bc *Blockchain) UtilityTokenHash() util.Uint160 { return bc.contracts.GAS.Hash } func hashAndIndexToBytes(h util.Uint256, index uint32) []byte { buf := io.NewBufBinWriter() buf.WriteBytes(h.BytesLE()) buf.WriteU32LE(index) return buf.Bytes() } func (bc *Blockchain) secondsPerBlock() int { return bc.config.SecondsPerBlock } func (bc *Blockchain) newInteropContext(trigger trigger.Type, d dao.DAO, block *block.Block, tx *transaction.Transaction) *interop.Context { ic := interop.NewContext(trigger, bc, d, bc.contracts.Contracts, block, tx, bc.log) switch { case tx != nil: ic.Container = tx case block != nil: ic.Container = block } return ic }