package transaction import ( "encoding/hex" "encoding/json" "errors" "fmt" "github.com/nspcc-dev/neo-go/pkg/crypto/hash" "github.com/nspcc-dev/neo-go/pkg/encoding/address" "github.com/nspcc-dev/neo-go/pkg/io" "github.com/nspcc-dev/neo-go/pkg/util" ) const ( // MaxTransactionSize is the upper limit size in bytes that a transaction can reach. It is // set to be 102400. MaxTransactionSize = 102400 // MaxValidUntilBlockIncrement is the upper increment size of blockhain height in blocs after // exceeding that a transaction should fail validation. It is set to be 2102400. MaxValidUntilBlockIncrement = 2102400 // MaxCosigners is maximum number of cosigners that can be contained within a transaction. // It is set to be 16. MaxCosigners = 16 ) // Transaction is a process recorded in the NEO blockchain. type Transaction struct { // The type of the transaction. Type TXType // The trading version which is currently 0. Version uint8 // Random number to avoid hash collision. Nonce uint32 // Address signed the transaction. Sender util.Uint160 // Fee to be burned. SystemFee util.Fixed8 // Fee to be distributed to consensus nodes. NetworkFee util.Fixed8 // Maximum blockchain height exceeding which // transaction should fail verification. ValidUntilBlock uint32 // Data specific to the type of the transaction. // This is always a pointer to a Transaction. Data TXer // Transaction attributes. Attributes []Attribute // Transaction cosigners (not include Sender). Cosigners []Cosigner // The inputs of the transaction. Inputs []Input // The outputs of the transaction. Outputs []Output // The scripts that comes with this transaction. // Scripts exist out of the verification script // and invocation script. Scripts []Witness // Hash of the transaction (double SHA256). hash util.Uint256 // Hash of the transaction used to verify it (single SHA256). verificationHash util.Uint256 // Trimmed indicates this is a transaction from trimmed // data. Trimmed bool } // NewTrimmedTX returns a trimmed transaction with only its hash // and Trimmed to true. func NewTrimmedTX(hash util.Uint256) *Transaction { return &Transaction{ hash: hash, Trimmed: true, } } // Hash returns the hash of the transaction. func (t *Transaction) Hash() util.Uint256 { if t.hash.Equals(util.Uint256{}) { if t.createHash() != nil { panic("failed to compute hash!") } } return t.hash } // VerificationHash returns the hash of the transaction used to verify it. func (t *Transaction) VerificationHash() util.Uint256 { if t.verificationHash.Equals(util.Uint256{}) { if t.createHash() != nil { panic("failed to compute hash!") } } return t.verificationHash } // AddOutput adds the given output to the transaction outputs. func (t *Transaction) AddOutput(out *Output) { t.Outputs = append(t.Outputs, *out) } // AddInput adds the given input to the transaction inputs. func (t *Transaction) AddInput(in *Input) { t.Inputs = append(t.Inputs, *in) } // DecodeBinary implements Serializable interface. func (t *Transaction) DecodeBinary(br *io.BinReader) { t.Type = TXType(br.ReadB()) t.Version = uint8(br.ReadB()) t.Nonce = br.ReadU32LE() t.Sender.DecodeBinary(br) t.SystemFee.DecodeBinary(br) if t.SystemFee < 0 { br.Err = errors.New("negative system fee") return } t.NetworkFee.DecodeBinary(br) if t.NetworkFee < 0 { br.Err = errors.New("negative network fee") return } if t.NetworkFee+t.SystemFee < t.SystemFee { br.Err = errors.New("too big fees: int 64 overflow") return } t.ValidUntilBlock = br.ReadU32LE() t.decodeData(br) br.ReadArray(&t.Attributes) br.ReadArray(&t.Cosigners, MaxCosigners) for i := 0; i < len(t.Cosigners); i++ { for j := i + 1; j < len(t.Cosigners); j++ { if t.Cosigners[i].Account.Equals(t.Cosigners[j].Account) { br.Err = errors.New("transaction cosigners should be unique") return } } } br.ReadArray(&t.Inputs) br.ReadArray(&t.Outputs) for i := range t.Outputs { if t.Outputs[i].Amount.LessThan(0) { br.Err = errors.New("negative output") return } } br.ReadArray(&t.Scripts) // Create the hash of the transaction at decode, so we dont need // to do it anymore. if br.Err == nil { br.Err = t.createHash() } } func (t *Transaction) decodeData(r *io.BinReader) { switch t.Type { case InvocationType: t.Data = &InvocationTX{} t.Data.(*InvocationTX).DecodeBinary(r) default: r.Err = fmt.Errorf("invalid TX type %x", t.Type) } } // EncodeBinary implements Serializable interface. func (t *Transaction) EncodeBinary(bw *io.BinWriter) { t.encodeHashableFields(bw) bw.WriteArray(t.Scripts) } // encodeHashableFields encodes the fields that are not used for // signing the transaction, which are all fields except the scripts. func (t *Transaction) encodeHashableFields(bw *io.BinWriter) { if t.Data == nil { bw.Err = errors.New("transaction has no data") return } bw.WriteB(byte(t.Type)) bw.WriteB(byte(t.Version)) bw.WriteU32LE(t.Nonce) t.Sender.EncodeBinary(bw) t.SystemFee.EncodeBinary(bw) t.NetworkFee.EncodeBinary(bw) bw.WriteU32LE(t.ValidUntilBlock) // Underlying TXer. t.Data.EncodeBinary(bw) // Attributes bw.WriteArray(t.Attributes) // Cosigners bw.WriteArray(t.Cosigners) // Inputs bw.WriteArray(t.Inputs) // Outputs bw.WriteArray(t.Outputs) } // createHash creates the hash of the transaction. func (t *Transaction) createHash() error { buf := io.NewBufBinWriter() t.encodeHashableFields(buf.BinWriter) if buf.Err != nil { return buf.Err } b := buf.Bytes() t.verificationHash = hash.Sha256(b) t.hash = hash.Sha256(t.verificationHash.BytesBE()) return nil } // GroupOutputByAssetID groups all TX outputs by their assetID. func (t Transaction) GroupOutputByAssetID() map[util.Uint256][]*Output { m := make(map[util.Uint256][]*Output) for i := range t.Outputs { hash := t.Outputs[i].AssetID m[hash] = append(m[hash], &t.Outputs[i]) } return m } // GetSignedPart returns a part of the transaction which must be signed. func (t *Transaction) GetSignedPart() []byte { buf := io.NewBufBinWriter() t.encodeHashableFields(buf.BinWriter) if buf.Err != nil { return nil } return buf.Bytes() } // Bytes converts the transaction to []byte func (t *Transaction) Bytes() []byte { buf := io.NewBufBinWriter() t.EncodeBinary(buf.BinWriter) if buf.Err != nil { return nil } return buf.Bytes() } // NewTransactionFromBytes decodes byte array into *Transaction func NewTransactionFromBytes(b []byte) (*Transaction, error) { tx := &Transaction{} r := io.NewBinReaderFromBuf(b) tx.DecodeBinary(r) if r.Err != nil { return nil, r.Err } return tx, nil } // FeePerByte returns NetworkFee of the transaction divided by // its size func (t *Transaction) FeePerByte() util.Fixed8 { return util.Fixed8(int64(t.NetworkFee) / int64(io.GetVarSize(t))) } // transactionJSON is a wrapper for Transaction and // used for correct marhalling of transaction.Data type transactionJSON struct { TxID util.Uint256 `json:"txid"` Size int `json:"size"` Type TXType `json:"type"` Version uint8 `json:"version"` Nonce uint32 `json:"nonce"` Sender string `json:"sender"` SystemFee util.Fixed8 `json:"sys_fee"` NetworkFee util.Fixed8 `json:"net_fee"` ValidUntilBlock uint32 `json:"valid_until_block"` Attributes []Attribute `json:"attributes"` Cosigners []Cosigner `json:"cosigners"` Inputs []Input `json:"vin"` Outputs []Output `json:"vout"` Scripts []Witness `json:"scripts"` Script string `json:"script,omitempty"` } // MarshalJSON implements json.Marshaler interface. func (t *Transaction) MarshalJSON() ([]byte, error) { tx := transactionJSON{ TxID: t.Hash(), Size: io.GetVarSize(t), Type: t.Type, Version: t.Version, Nonce: t.Nonce, Sender: address.Uint160ToString(t.Sender), ValidUntilBlock: t.ValidUntilBlock, Attributes: t.Attributes, Cosigners: t.Cosigners, Inputs: t.Inputs, Outputs: t.Outputs, Scripts: t.Scripts, SystemFee: t.SystemFee, NetworkFee: t.NetworkFee, } switch t.Type { case InvocationType: tx.Script = hex.EncodeToString(t.Data.(*InvocationTX).Script) } return json.Marshal(tx) } // UnmarshalJSON implements json.Unmarshaler interface. func (t *Transaction) UnmarshalJSON(data []byte) error { tx := new(transactionJSON) if err := json.Unmarshal(data, tx); err != nil { return err } t.Type = tx.Type t.Version = tx.Version t.Nonce = tx.Nonce t.ValidUntilBlock = tx.ValidUntilBlock t.Attributes = tx.Attributes t.Cosigners = tx.Cosigners t.Inputs = tx.Inputs t.Outputs = tx.Outputs t.Scripts = tx.Scripts t.SystemFee = tx.SystemFee t.NetworkFee = tx.NetworkFee sender, err := address.StringToUint160(tx.Sender) if err != nil { return errors.New("cannot unmarshal tx: bad sender") } t.Sender = sender switch tx.Type { case InvocationType: bytes, err := hex.DecodeString(tx.Script) if err != nil { return err } t.Data = &InvocationTX{ Script: bytes, } } if t.Hash() != tx.TxID { return errors.New("txid doesn't match transaction hash") } return nil }