package core import ( "bytes" "fmt" "math" "math/big" "sort" "strconv" "sync/atomic" "time" "github.com/CityOfZion/neo-go/config" "github.com/CityOfZion/neo-go/pkg/core/state" "github.com/CityOfZion/neo-go/pkg/core/storage" "github.com/CityOfZion/neo-go/pkg/core/transaction" "github.com/CityOfZion/neo-go/pkg/crypto/keys" "github.com/CityOfZion/neo-go/pkg/io" "github.com/CityOfZion/neo-go/pkg/smartcontract" "github.com/CityOfZion/neo-go/pkg/smartcontract/trigger" "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 = "0.0.3" // 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 // Data access object for CRUD operations around storage. dao *dao // 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 // 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 // cache for block verification keys. keyCache map[util.Uint160]map[string]*keys.PublicKey } 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, dao: newDao(s), headersOp: make(chan headersOpFunc), headersOpDone: make(chan struct{}), stopCh: make(chan struct{}), runToExitCh: make(chan struct{}), memPool: NewMemPool(50000), keyCache: make(map[util.Uint160]map[string]*keys.PublicKey), } 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 { log.Infof("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. log.Infof("restoring blockchain with version: %s", 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([]*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 { log.Warnf("failed to persist: %s", err) } if err := bc.dao.store.Close(); err != nil { log.Warnf("failed to close db: %s", 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 { log.Warnf("failed to persist blockchain: %s", 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) 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().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) } } } } 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.dao.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() { updateHeaderHeightMetric(headerList.Len() - 1) if err = bc.dao.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().BytesLE()) 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 { cache := newCachedDao(bc.dao.store) if err := cache.StoreAsBlock(block, 0); 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(), NewUnspentCoinState(len(tx.Outputs))); 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 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 := cache.GetUnspentCoinStateOrNew(input.PrevHash) if err != nil { return err } unspent.states[input.PrevIndex] = state.CoinSpent if err = cache.PutUnspentCoinState(input.PrevHash, unspent); err != nil { return err } prevTXOutput := prevTX.Outputs[input.PrevIndex] account, err := cache.GetAccountStateOrNew(prevTXOutput.ScriptHash) if err != nil { return err } if prevTXOutput.AssetID.Equals(governingTokenTX().Hash()) { spentCoin := NewSpentCoinState(input.PrevHash, prevTXHeight) spentCoin.items[input.PrevIndex] = block.Index if err = cache.PutSpentCoinState(input.PrevHash, spentCoin); err != nil { return err } if err = processTXWithValidatorsSubtract(account, cache, prevTXOutput.Amount); 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 { copy(account.Balances[prevTXOutput.AssetID][index:], account.Balances[prevTXOutput.AssetID][index+1:]) account.Balances[prevTXOutput.AssetID] = account.Balances[prevTXOutput.AssetID][:balancesLen-1] } } if err = cache.PutAccountState(account); 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.GetSpentCoinsOrNew(input.PrevHash) if err != nil { return err } if scs.txHash == input.PrevHash { // Existing scs. delete(scs.items, input.PrevIndex) if err = cache.PutSpentCoinState(input.PrevHash, scs); err != nil { return err } } else { // Uninitialized, new, forget about it. if err = cache.DeleteSpentCoinState(input.PrevHash); err != nil { return err } } } case *transaction.EnrollmentTX: if err := processEnrollmentTX(cache, t); err != nil { return err } case *transaction.StateTX: if err := processStateTX(cache, t); err != nil { return err } case *transaction.PublishTX: var properties smartcontract.PropertyState if t.NeedStorage { properties |= smartcontract.HasStorage } contract := &state.Contract{ 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, } if err := cache.PutContractState(contract); err != nil { return err } case *transaction.InvocationTX: systemInterop := newInteropContext(trigger.Application, bc, cache.store, block, tx) v := bc.spawnVMWithInterops(systemInterop) v.SetCheckedHash(tx.VerificationHash().BytesBE()) v.LoadScript(t.Script) 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" { continue } from, ok := arr[1].Value().([]byte) if !ok { continue } to, ok := arr[2].Value().([]byte) if !ok { continue } amount, ok := arr[3].Value().(*big.Int) if !ok { continue } // TODO: #498 _, _, _, _ = op, from, to, amount } } else { log.WithFields(log.Fields{ "tx": tx.Hash().StringLE(), "block": block.Index, "err": err, }).Warn("contract invocation failed") } aer := &state.AppExecResult{ TxHash: tx.Hash(), Trigger: trigger.Application, VMState: v.State(), GasConsumed: util.Fixed8(0), Stack: v.Stack("estack"), Events: systemInterop.notifications, } err = cache.PutAppExecResult(aer) if err != nil { return errors.Wrap(err, "failed to store notifications") } } } _, err := cache.Persist() if err != nil { return err } bc.topBlock.Store(block) atomic.StoreUint32(&bc.blockHeight, block.Index) updateBlockHeightMetric(block.Index) for _, tx := range block.Transactions { bc.memPool.Remove(tx.Hash()) } return nil } // processOutputs processes transaction outputs. func processOutputs(tx *transaction.Transaction, dao *cachedDao) 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 } if err = processTXWithValidatorsAdd(&output, account, dao); err != nil { return err } } return nil } func processTXWithValidatorsAdd(output *transaction.Output, account *state.Account, dao *cachedDao) error { if output.AssetID.Equals(governingTokenTX().Hash()) && len(account.Votes) > 0 { for _, vote := range account.Votes { validatorState, err := dao.GetValidatorStateOrNew(vote) if err != nil { return err } validatorState.Votes += output.Amount if err = dao.PutValidatorState(validatorState); err != nil { return err } } } return nil } func processTXWithValidatorsSubtract(account *state.Account, dao *cachedDao, toSubtract util.Fixed8) error { for _, vote := range account.Votes { validator, err := dao.GetValidatorStateOrNew(vote) if err != nil { return err } validator.Votes -= toSubtract if !validator.RegisteredAndHasVotes() { if err := dao.DeleteValidatorState(validator); err != nil { return err } } else { if err := dao.PutValidatorState(validator); err != nil { return err } } } return nil } func processValidatorStateDescriptor(descriptor *transaction.StateDescriptor, dao *cachedDao) error { publicKey := &keys.PublicKey{} err := publicKey.DecodeBytes(descriptor.Key) if err != nil { return err } validatorState, err := dao.GetValidatorStateOrNew(publicKey) if err != nil { return err } if descriptor.Field == "Registered" { isRegistered, err := strconv.ParseBool(string(descriptor.Value)) if err != nil { return err } validatorState.Registered = isRegistered return dao.PutValidatorState(validatorState) } return nil } func processAccountStateDescriptor(descriptor *transaction.StateDescriptor, dao *cachedDao) error { hash, err := util.Uint160DecodeBytesBE(descriptor.Key) if err != nil { return err } account, err := dao.GetAccountStateOrNew(hash) if err != nil { return err } if descriptor.Field == "Votes" { balance := account.GetBalanceValues()[governingTokenTX().Hash()] if err = processTXWithValidatorsSubtract(account, dao, balance); err != nil { return err } votes := keys.PublicKeys{} err := votes.DecodeBytes(descriptor.Value) if err != nil { return err } if votes.Len() != len(account.Votes) { account.Votes = votes for _, vote := range votes { validator, err := dao.GetValidatorStateOrNew(vote) if err != nil { return err } if err := dao.PutValidatorState(validator); 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 } log.WithFields(log.Fields{ "persistedBlocks": diff, "persistedKeys": persisted, "headerHeight": storedHeaderHeight, "blockHeight": bHeight, "took": time.Since(start), }).Info("blockchain persist completed") // 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) } // 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, error) { topBlock := bc.topBlock.Load() if topBlock != nil { if tb, ok := topBlock.(*Block); ok && tb.Hash().Equals(hash) { return tb, nil } } block, err := bc.dao.GetBlock(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 } // GetHeader returns data block header identified with the given hash value. func (bc *Blockchain) GetHeader(hash util.Uint256) (*Header, error) { topBlock := bc.topBlock.Load() if topBlock != nil { if tb, ok := topBlock.(*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 { log.Warnf("failed to get asset state %s : %s", assetID, 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 { log.Warnf("failed to get contract state: %s", 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 { 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 := bc.dao.GetUnspentCoinState(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 block == nil { if ok := bc.memPool.Verify(t); !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") } 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.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) 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") } //GetStandByValidators returns validators from the configuration. func (bc *Blockchain) GetStandByValidators() (keys.PublicKeys, error) { return getValidators(bc.config) } // GetValidators returns validators. // Golang implementation of GetValidators method in C# (https://github.com/neo-project/neo/blob/c64748ecbac3baeb8045b16af0d518398a6ced24/neo/Persistence/Snapshot.cs#L182) func (bc *Blockchain) GetValidators(txes ...*transaction.Transaction) ([]*keys.PublicKey, error) { cache := newCachedDao(bc.dao.store) if len(txes) > 0 { for _, tx := range txes { // iterate through outputs for index, output := range tx.Outputs { accountState, err := cache.GetAccountState(output.ScriptHash) if err != nil { return nil, err } accountState.Balances[output.AssetID] = append(accountState.Balances[output.AssetID], state.UnspentBalance{ Tx: tx.Hash(), Index: uint16(index), Value: output.Amount, }) if err := cache.PutAccountState(accountState); err != nil { return nil, err } if err = processTXWithValidatorsAdd(&output, accountState, cache); err != nil { return nil, err } } // group inputs by the same previous hash and iterate through inputs group := make(map[util.Uint256][]*transaction.Input) for i := range tx.Inputs { hash := tx.Inputs[i].PrevHash group[hash] = append(group[hash], &tx.Inputs[i]) } for hash, inputs := range group { prevTx, _, err := cache.GetTransaction(hash) if err != nil { return nil, err } // process inputs for _, input := range inputs { prevOutput := prevTx.Outputs[input.PrevIndex] accountState, err := cache.GetAccountStateOrNew(prevOutput.ScriptHash) if err != nil { return nil, err } // process account state votes: if there are any -> validators will be updated. if err = processTXWithValidatorsSubtract(accountState, cache, prevOutput.Amount); err != nil { return nil, err } delete(accountState.Balances, prevOutput.AssetID) if err = cache.PutAccountState(accountState); err != nil { return nil, err } } } switch t := tx.Data.(type) { case *transaction.EnrollmentTX: if err := processEnrollmentTX(cache, t); err != nil { return nil, err } case *transaction.StateTX: if err := processStateTX(cache, t); err != nil { return nil, err } } } } validators := cache.GetValidators() count := state.GetValidatorsWeightedAverage(validators) standByValidators, err := bc.GetStandByValidators() if err != nil { return nil, err } if count < len(standByValidators) { count = len(standByValidators) } uniqueSBValidators := standByValidators.Unique() pubKeys := keys.PublicKeys{} for _, validator := range validators { if validator.RegisteredAndHasVotes() || uniqueSBValidators.Contains(validator.PublicKey) { pubKeys = append(pubKeys, validator.PublicKey) } } sort.Sort(sort.Reverse(pubKeys)) if pubKeys.Len() >= count { return pubKeys[:count], nil } result := pubKeys.Unique() for i := 0; i < uniqueSBValidators.Len() && result.Len() < count; i++ { result = append(result, uniqueSBValidators[i]) } return result, nil } func processStateTX(dao *cachedDao, tx *transaction.StateTX) error { for _, desc := range tx.Descriptors { switch desc.Type { case transaction.Account: if err := processAccountStateDescriptor(desc, dao); err != nil { return err } case transaction.Validator: if err := processValidatorStateDescriptor(desc, dao); err != nil { return err } } } return nil } func processEnrollmentTX(dao *cachedDao, tx *transaction.EnrollmentTX) error { validatorState, err := dao.GetValidatorStateOrNew(&tx.PublicKey) if err != nil { return err } validatorState.Registered = true return dao.PutValidatorState(validatorState) } // 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.Uint160DecodeBytesBE(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 } // spawnVMWithInterops returns a VM with script getter and interop functions set // up for current blockchain. func (bc *Blockchain) spawnVMWithInterops(interopCtx *interopContext) *vm.VM { vm := vm.New() vm.SetScriptGetter(func(hash util.Uint160) []byte { cs, err := interopCtx.dao.GetContractState(hash) if err != nil { return nil } return cs.Script }) vm.RegisterInteropGetter(interopCtx.getSystemInterop) vm.RegisterInteropGetter(interopCtx.getNeoInterop) return vm } // GetTestVM returns a VM and a Store setup for a test run of some sort of code. func (bc *Blockchain) GetTestVM() (*vm.VM, storage.Store) { tmpStore := storage.NewMemCachedStore(bc.dao.store) systemInterop := newInteropContext(trigger.Application, bc, tmpStore, nil, nil) vm := bc.spawnVMWithInterops(systemInterop) return vm, tmpStore } // verifyHashAgainstScript verifies given hash against the given witness. func (bc *Blockchain) verifyHashAgainstScript(hash util.Uint160, witness *transaction.Witness, checkedHash util.Uint256, interopCtx *interopContext, useKeys bool) 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 := bc.spawnVMWithInterops(interopCtx) vm.SetCheckedHash(checkedHash.BytesBE()) vm.LoadScript(verification) vm.LoadScript(witness.InvocationScript) if useKeys && bc.keyCache[hash] != nil { vm.SetPublicKeys(bc.keyCache[hash]) } 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") } if useKeys && bc.keyCache[hash] == nil { bc.keyCache[hash] = vm.GetPublicKeys() } } 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(trigger.Verification, bc, bc.dao.store, block, t) for i := 0; i < len(hashes); i++ { err := bc.verifyHashAgainstScript(hashes[i], &witnesses[i], t.VerificationHash(), interopCtx, false) 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(trigger.Verification, bc, bc.dao.store, nil, nil) return bc.verifyHashAgainstScript(hash, &block.Script, block.VerificationHash(), interopCtx, true) } 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 }