package client import ( "errors" "fmt" "strings" "github.com/nspcc-dev/neo-go/pkg/core/native/nativenames" "github.com/nspcc-dev/neo-go/pkg/core/native/noderoles" "github.com/nspcc-dev/neo-go/pkg/core/transaction" "github.com/nspcc-dev/neo-go/pkg/crypto/hash" "github.com/nspcc-dev/neo-go/pkg/crypto/keys" "github.com/nspcc-dev/neo-go/pkg/encoding/fixedn" sc "github.com/nspcc-dev/neo-go/pkg/smartcontract" "github.com/nspcc-dev/neo-go/pkg/util" "github.com/nspcc-dev/neo-go/pkg/vm/opcode" "github.com/nspcc-dev/neo-go/pkg/wallet" "go.uber.org/zap" ) type ( notary struct { txValidTime uint32 // minimum amount of blocks when mainTx will be valid roundTime uint32 // extra amount of blocks to synchronize sidechain height diff of inner ring nodes fallbackTime uint32 // amount of blocks before fallbackTx will be sent alphabetSource AlphabetKeys // source of alphabet node keys to prepare witness notary util.Uint160 proxy util.Uint160 } notaryCfg struct { txValidTime, roundTime, fallbackTime uint32 alphabetSource AlphabetKeys } AlphabetKeys func() (keys.PublicKeys, error) NotaryOption func(*notaryCfg) ) const ( defaultNotaryValidTime = 50 defaultNotaryRoundTime = 100 defaultNotaryFallbackTime = 40 notaryBalanceOfMethod = "balanceOf" setDesignateMethod = "designateAsRole" notaryBalanceErrMsg = "can't fetch notary balance" notaryNotEnabledPanicMsg = "notary support was not enabled on this client" ) var errUnexpectedItems = errors.New("invalid number of NEO VM arguments on stack") func defaultNotaryConfig(c *Client) *notaryCfg { return ¬aryCfg{ txValidTime: defaultNotaryValidTime, roundTime: defaultNotaryRoundTime, fallbackTime: defaultNotaryFallbackTime, alphabetSource: c.Committee, } } // EnableNotarySupport creates notary structure in client that provides // ability for client to get alphabet keys from committee or provided source // and use proxy contract script hash to create tx for notary contract. func (c *Client) EnableNotarySupport(proxy util.Uint160, opts ...NotaryOption) error { cfg := defaultNotaryConfig(c) for _, opt := range opts { opt(cfg) } notaryContract, err := c.client.GetNativeContractHash(nativenames.Notary) if err != nil { return fmt.Errorf("can't get notary contract script hash: %w", err) } c.notary = ¬ary{ notary: notaryContract, proxy: proxy, txValidTime: cfg.txValidTime, roundTime: cfg.roundTime, fallbackTime: cfg.fallbackTime, alphabetSource: cfg.alphabetSource, } return nil } // NotaryEnabled returns true if notary support was enabled in this instance // of client by calling `EnableNotarySupport()`. Otherwise returns false. func (c *Client) NotaryEnabled() bool { return c.notary != nil } // DepositNotary calls notary deposit method. Deposit is required to operate // with notary contract. It used by notary contract in to produce fallback tx // if main tx failed to create. Deposit isn't last forever, so it should // be called periodically. Notary support should be enabled in client to // use this function. // // This function must be invoked after `EnableNotarySupport()` otherwise it // throws panic. func (c *Client) DepositNotary(amount fixedn.Fixed8, delta uint32) (util.Uint256, error) { if c.notary == nil { panic(notaryNotEnabledPanicMsg) } bc, err := c.client.GetBlockCount() if err != nil { return util.Uint256{}, fmt.Errorf("can't get blockchain height: %w", err) } txHash, err := c.client.TransferNEP17( c.acc, c.notary.notary, c.gas, int64(amount), 0, []interface{}{c.acc.PrivateKey().GetScriptHash(), int64(bc + delta)}, nil, ) if err != nil { return util.Uint256{}, fmt.Errorf("can't make notary deposit: %w", err) } c.logger.Debug("notary deposit invoke", zap.Int64("amount", int64(amount)), zap.Uint32("expire_at", bc+delta), zap.Stringer("tx_hash", txHash.Reverse())) return txHash, nil } // GetNotaryDeposit returns deposit of client's account in notary contract. // Notary support should be enabled in client to use this function. // // This function must be invoked after `EnableNotarySupport()` otherwise it // throws panic. func (c *Client) GetNotaryDeposit() (int64, error) { if c.notary == nil { panic(notaryNotEnabledPanicMsg) } sh := c.acc.PrivateKey().PublicKey().GetScriptHash() items, err := c.TestInvoke(c.notary.notary, notaryBalanceOfMethod, sh) if err != nil { return 0, fmt.Errorf("%v: %w", notaryBalanceErrMsg, err) } if len(items) != 1 { return 0, fmt.Errorf("%v: %w", notaryBalanceErrMsg, errUnexpectedItems) } bigIntDeposit, err := items[0].TryInteger() if err != nil { return 0, fmt.Errorf("%v: %w", notaryBalanceErrMsg, err) } return bigIntDeposit.Int64(), nil } // UpdateNotaryList updates list of notary nodes in designate contract. Requires // committee multi signature. // // This function must be invoked after `EnableNotarySupport()` otherwise it // throws panic. func (c *Client) UpdateNotaryList(list keys.PublicKeys) error { if c.notary == nil { panic(notaryNotEnabledPanicMsg) } return c.notaryInvokeAsCommittee(c.designate, setDesignateMethod, noderoles.P2PNotary, list, ) } // UpdateNeoFSAlphabetList updates list of alphabet nodes in designate contract. // As for side chain list should contain all inner ring nodes. // Requires committee multi signature. // // This function must be invoked after `EnableNotarySupport()` otherwise it // throws panic. func (c *Client) UpdateNeoFSAlphabetList(list keys.PublicKeys) error { if c.notary == nil { panic(notaryNotEnabledPanicMsg) } return c.notaryInvokeAsCommittee(c.designate, setDesignateMethod, noderoles.NeoFSAlphabet, list, ) } // NotaryInvoke invokes contract method by sending tx to notary contract in // blockchain. Fallback tx is a `RET`. If Notary support is not enabled // it fallbacks to a simple `Invoke()`. // // This function must be invoked after `EnableNotarySupport()` otherwise it // throws panic. func (c *Client) NotaryInvoke(contract util.Uint160, fee fixedn.Fixed8, method string, args ...interface{}) error { if c.notary == nil { return c.Invoke(contract, fee, method, args...) } return c.notaryInvoke(false, contract, method, args...) } func (c *Client) notaryInvokeAsCommittee(contract util.Uint160, method string, args ...interface{}) error { return c.notaryInvoke(true, contract, method, args...) } func (c *Client) notaryInvoke(committee bool, contract util.Uint160, method string, args ...interface{}) error { alphabetList, err := c.notary.alphabetSource() // prepare arguments for test invocation if err != nil { return err } _, n := mn(alphabetList, committee) u8n := uint8(n) cosigners, err := c.notaryCosigners(alphabetList, committee) if err != nil { return err } params, err := invocationParams(args...) if err != nil { return err } // make test invocation of the method test, err := c.client.InvokeFunction(contract, method, params, cosigners) if err != nil { return err } // check invocation state if test.State != HaltState { return &NotHaltStateError{state: test.State, exception: test.FaultException} } // if test invocation failed, then return error if len(test.Script) == 0 { return errEmptyInvocationScript } // after test invocation we build main multisig transaction multiaddrAccount, err := c.notaryMultisigAccount(alphabetList, committee) if err != nil { return err } until, err := c.notaryTxValidationLimit() if err != nil { return err } // prepare main tx mainTx := &transaction.Transaction{ Nonce: 1, SystemFee: test.GasConsumed, ValidUntilBlock: until, Script: test.Script, Attributes: []transaction.Attribute{ { Type: transaction.NotaryAssistedT, Value: &transaction.NotaryAssisted{NKeys: u8n}, }, }, Signers: cosigners, } // calculate notary fee notaryFee, err := c.client.CalculateNotaryFee(u8n) if err != nil { return err } // add network fee for cosigners err = c.client.AddNetworkFee( mainTx, notaryFee, c.notaryAccounts(multiaddrAccount)..., ) if err != nil { return err } // define witnesses mainTx.Scripts = c.notaryWitnesses(multiaddrAccount, mainTx) resp, err := c.client.SignAndPushP2PNotaryRequest(mainTx, []byte{byte(opcode.RET)}, -1, 0, c.notary.fallbackTime, c.acc) if err != nil && !alreadyOnChainError(err) { return err } c.logger.Debug("notary request invoked", zap.String("method", method), zap.Stringer("tx_hash", resp.Hash().Reverse())) return nil } func (c *Client) notaryCosigners(ir []*keys.PublicKey, committee bool) ([]transaction.Signer, error) { s := make([]transaction.Signer, 0, 3) // first we have proxy contract signature, as it will pay for the execution s = append(s, transaction.Signer{ Account: c.notary.proxy, Scopes: transaction.None, }) // then we have inner ring multiaddress signature m, _ := mn(ir, committee) multisigScript, err := sc.CreateMultiSigRedeemScript(m, ir) if err != nil { return nil, fmt.Errorf("can't create ir multisig redeem script: %w", err) } s = append(s, transaction.Signer{ Account: hash.Hash160(multisigScript), Scopes: transaction.Global, }) // last one is a placeholder for notary contract signature s = append(s, transaction.Signer{ Account: c.notary.notary, Scopes: transaction.None, }) return s, nil } func (c *Client) notaryAccounts(multiaddr *wallet.Account) []*wallet.Account { if multiaddr == nil { return nil } a := make([]*wallet.Account, 0, 3) // first we have proxy account, as it will pay for the execution a = append(a, &wallet.Account{ Contract: &wallet.Contract{ Deployed: true, }, }) // then we have inner ring multiaddress account a = append(a, multiaddr) // last one is a placeholder for notary contract account a = append(a, &wallet.Account{ Contract: &wallet.Contract{}, }) return a } func (c *Client) notaryWitnesses(multiaddr *wallet.Account, tx *transaction.Transaction) []transaction.Witness { if multiaddr == nil || tx == nil { return nil } w := make([]transaction.Witness, 0, 3) // first we have empty proxy witness, because notary will execute `Verify` // method on the proxy contract to check witness w = append(w, transaction.Witness{ InvocationScript: []byte{}, VerificationScript: []byte{}, }) // then we have inner ring multiaddress witness w = append(w, transaction.Witness{ InvocationScript: append( []byte{byte(opcode.PUSHDATA1), 64}, multiaddr.PrivateKey().SignHashable(uint32(c.client.GetNetwork()), tx)..., ), VerificationScript: multiaddr.GetVerificationScript(), }) // last one is a placeholder for notary contract witness w = append(w, transaction.Witness{ InvocationScript: append( []byte{byte(opcode.PUSHDATA1), 64}, make([]byte, 64)..., ), VerificationScript: []byte{}, }) return w } func (c *Client) notaryMultisigAccount(ir []*keys.PublicKey, committee bool) (*wallet.Account, error) { m, _ := mn(ir, committee) multisigAccount := wallet.NewAccountFromPrivateKey(c.acc.PrivateKey()) err := multisigAccount.ConvertMultisig(m, ir) if err != nil { return nil, fmt.Errorf("can't make inner ring multisig wallet: %w", err) } return multisigAccount, nil } func (c *Client) notaryTxValidationLimit() (uint32, error) { bc, err := c.client.GetBlockCount() if err != nil { return 0, fmt.Errorf("can't get current blockchain height: %w", err) } min := bc + c.notary.txValidTime rounded := (min/c.notary.roundTime + 1) * c.notary.roundTime return rounded, nil } func invocationParams(args ...interface{}) ([]sc.Parameter, error) { params := make([]sc.Parameter, 0, len(args)) for i := range args { param, err := toStackParameter(args[i]) if err != nil { return nil, err } params = append(params, param) } return params, nil } // mn returns M and N multi signature numbers. For NeoFS N is a length of // inner ring list, and M is a 2/3+1 of it (like in dBFT). If committee is // true, returns M as N/2+1. func mn(ir []*keys.PublicKey, committee bool) (m int, n int) { n = len(ir) if committee { m = n/2 + 1 } else { m = n*2/3 + 1 } return } // WithTxValidTime returns a notary support option for client // that specifies minimum amount of blocks when mainTx will be valid. func WithTxValidTime(t uint32) NotaryOption { return func(c *notaryCfg) { c.txValidTime = t } } // WithRoundTime returns a notary support option for client // that specifies extra blocks to synchronize side chain // height diff of inner ring nodes. func WithRoundTime(t uint32) NotaryOption { return func(c *notaryCfg) { c.roundTime = t } } // WithFallbackTime returns a notary support option for client // that specifies amount of blocks before fallbackTx will be sent. // Should be less than TxValidTime. func WithFallbackTime(t uint32) NotaryOption { return func(c *notaryCfg) { c.fallbackTime = t } } // WithAlphabetSource returns a notary support option for client // that specifies function to return list of alphabet node keys. // By default notary subsystem uses committee as a source. This is // valid for side chain but notary in main chain should override it. func WithAlphabetSource(t AlphabetKeys) NotaryOption { return func(c *notaryCfg) { c.alphabetSource = t } } const alreadyOnChainErrorMessage = "already on chain" // Neo RPC node can return `core.ErrInvalidAttribute` error with // `conflicting transaction <> is already on chain` message. This // error is expected and ignored. As soon as main tx persisted on // chain everything is fine. This happens because notary contract // requires 5 out of 7 signatures to send main tx, thus last two // notary requests may be processed after main tx appeared on chain. func alreadyOnChainError(err error) bool { return strings.Contains(err.Error(), alreadyOnChainErrorMessage) }