package client import ( "crypto/elliptic" "github.com/nspcc-dev/neo-go/pkg/core/native/nativenames" "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" "github.com/pkg/errors" "go.uber.org/zap" ) type ( notary struct { // extra fee to check witness of proxy contract // neo-go does not have an option to calculate it exactly right now extraVerifyFee int64 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 notary util.Uint160 proxy util.Uint160 netmap util.Uint160 } notaryCfg struct { txValidTime, roundTime, fallbackTime uint32 } NotaryOption func(*notaryCfg) ) const ( defaultNotaryValidTime = 50 defaultNotaryRoundTime = 100 defaultNotaryFallbackTime = 40 innerRingListMethod = "innerRingList" notaryBalanceOfMethod = "balanceOf" notaryBalanceErrMsg = "can't fetch notary balance" ) var ( errNotaryNotEnabled = errors.New("notary support was not enabled on this client") errInvalidIR = errors.New("invalid inner ring list from netmap contract") errUnexpectedItems = errors.New("invalid number of NEO VM arguments on stack") ) func defaultNotaryConfig() *notaryCfg { return ¬aryCfg{ txValidTime: defaultNotaryValidTime, roundTime: defaultNotaryRoundTime, fallbackTime: defaultNotaryFallbackTime, } } // EnableNotarySupport creates notary structure in client that provides // ability for client to get inner ring list from netmap contract and // use proxy contract script hash to create tx for notary contract. func (c *Client) EnableNotarySupport(proxy, netmap util.Uint160, opts ...NotaryOption) error { cfg := defaultNotaryConfig() for _, opt := range opts { opt(cfg) } notaryContract, err := c.client.GetNativeContractHash(nativenames.Notary) if err != nil { return errors.Wrap(err, "can't get notary contract script hash") } c.notary = ¬ary{ notary: notaryContract, proxy: proxy, netmap: netmap, txValidTime: cfg.txValidTime, roundTime: cfg.roundTime, fallbackTime: cfg.fallbackTime, } return 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. func (c *Client) DepositNotary(amount fixedn.Fixed8, delta uint32) error { if c.notary == nil { return errNotaryNotEnabled } bc, err := c.client.GetBlockCount() if err != nil { return errors.Wrap(err, "can't get blockchain height") } txHash, err := c.client.TransferNEP17( c.acc, c.notary.notary, c.gas, int64(amount), 0, []interface{}{c.acc.PrivateKey().GetScriptHash(), int64(bc + delta)}, ) if err != nil { return errors.Wrap(err, "can't make notary deposit") } c.logger.Debug("notary deposit invoke", zap.Int64("amount", int64(amount)), zap.Uint32("expire_at", bc+delta), zap.Stringer("tx_hash", txHash)) return nil } // GetNotaryDeposit returns deposit of client's account in notary contract. // Notary support should be enabled in client to use this function. func (c *Client) GetNotaryDeposit() (int64, error) { if c.notary == nil { return 0, errNotaryNotEnabled } sh := c.acc.PrivateKey().PublicKey().GetScriptHash() items, err := c.TestInvoke(c.notary.notary, notaryBalanceOfMethod, sh) if err != nil { return 0, errors.Wrap(err, notaryBalanceErrMsg) } if len(items) != 1 { return 0, errors.Wrap(errUnexpectedItems, notaryBalanceErrMsg) } bigIntDeposit, err := items[0].TryInteger() if err != nil { return 0, errors.Wrap(err, notaryBalanceErrMsg) } return bigIntDeposit.Int64(), nil } // Invoke invokes contract method by sending tx to notary contract in // blockchain. Fallback tx is a `RET`. Notary support should be enabled // in client to use this function. // // Supported args types: int64, string, util.Uint160, []byte and bool. func (c *Client) NotaryInvoke(contract util.Uint160, method string, args ...interface{}) error { 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 { if c.notary == nil { return errNotaryNotEnabled } // prepare arguments for test invocation irList, err := c.notaryInnerRingList() if err != nil { return err } _, n := mn(irList, committee) u8n := uint8(n) cosigners, err := c.notaryCosigners(irList, 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 } // 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(irList, 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, Network: c.client.GetNetwork(), } // 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 { 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, errors.Wrap(err, "can't create ir multisig redeem script") } 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().Sign(tx.GetSignedPart())..., ), 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) notaryInnerRingList() ([]*keys.PublicKey, error) { data, err := c.TestInvoke(c.notary.netmap, innerRingListMethod) if err != nil { return nil, errors.Wrap(err, "test invoke error") } if len(data) == 0 { return nil, errors.Wrap(errInvalidIR, "test invoke returned empty stack") } prms, err := ArrayFromStackItem(data[0]) if err != nil { return nil, errors.Wrap(err, "test invoke returned non array element") } res := make([]*keys.PublicKey, 0, len(prms)) for i := range prms { nodePrms, err := ArrayFromStackItem(prms[i]) if err != nil { return nil, errors.Wrap(err, "inner ring node structure is not an array") } if len(nodePrms) == 0 { return nil, errors.Wrap(errInvalidIR, "inner ring node structure is empty array") } rawKey, err := BytesFromStackItem(nodePrms[0]) if err != nil { return nil, errors.Wrap(err, "inner ring public key is not slice of bytes") } key, err := keys.NewPublicKeyFromBytes(rawKey, elliptic.P256()) if err != nil { return nil, errors.Wrap(err, "can't parse inner ring public key bytes") } res = append(res, key) } return res, nil } 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, errors.Wrap(err, "can't make inner ring multisig wallet") } return multisigAccount, nil } func (c *Client) notaryTxValidationLimit() (uint32, error) { bc, err := c.client.GetBlockCount() if err != nil { return 0, errors.Wrap(err, "can't get current blockchain height") } 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 } }