package payload import ( "bytes" "errors" "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/io" "github.com/nspcc-dev/neo-go/pkg/util" "github.com/nspcc-dev/neo-go/pkg/vm/opcode" ) // P2PNotaryRequest contains main and fallback transactions for the Notary service. type P2PNotaryRequest struct { MainTransaction *transaction.Transaction `json:"maintx"` FallbackTransaction *transaction.Transaction `json:"fallbacktx"` Witness transaction.Witness hash util.Uint256 } // NewP2PNotaryRequestFromBytes decodes a P2PNotaryRequest from the given bytes. func NewP2PNotaryRequestFromBytes(b []byte) (*P2PNotaryRequest, error) { req := &P2PNotaryRequest{} br := io.NewBinReaderFromBuf(b) req.DecodeBinary(br) if br.Err != nil { return nil, br.Err } if br.Len() != 0 { return nil, errors.New("additional data after the payload") } return req, nil } // Bytes returns serialized P2PNotaryRequest payload. func (r *P2PNotaryRequest) Bytes() ([]byte, error) { buf := io.NewBufBinWriter() r.EncodeBinary(buf.BinWriter) if buf.Err != nil { return nil, buf.Err } return buf.Bytes(), nil } // Hash returns payload's hash. func (r *P2PNotaryRequest) Hash() util.Uint256 { if r.hash.Equals(util.Uint256{}) { if r.createHash() != nil { panic("failed to compute hash!") } } return r.hash } // createHash creates hash of the payload. func (r *P2PNotaryRequest) createHash() error { buf := io.NewBufBinWriter() r.encodeHashableFields(buf.BinWriter) r.hash = hash.Sha256(buf.Bytes()) return nil } // DecodeBinaryUnsigned reads payload from the w excluding signature. func (r *P2PNotaryRequest) decodeHashableFields(br *io.BinReader) { r.MainTransaction = &transaction.Transaction{} r.FallbackTransaction = &transaction.Transaction{} r.MainTransaction.DecodeBinary(br) r.FallbackTransaction.DecodeBinary(br) if br.Err == nil { br.Err = r.isValid() } if br.Err == nil { br.Err = r.createHash() } } // DecodeBinary implements the io.Serializable interface. func (r *P2PNotaryRequest) DecodeBinary(br *io.BinReader) { r.decodeHashableFields(br) if br.Err == nil { r.Witness.DecodeBinary(br) } } // encodeHashableFields writes payload to the w excluding signature. func (r *P2PNotaryRequest) encodeHashableFields(bw *io.BinWriter) { r.MainTransaction.EncodeBinary(bw) r.FallbackTransaction.EncodeBinary(bw) } // EncodeBinary implements the Serializable interface. func (r *P2PNotaryRequest) EncodeBinary(bw *io.BinWriter) { r.encodeHashableFields(bw) r.Witness.EncodeBinary(bw) } func (r *P2PNotaryRequest) isValid() error { nKeysMain := r.MainTransaction.GetAttributes(transaction.NotaryAssistedT) if len(nKeysMain) == 0 { return errors.New("main transaction should have NotaryAssisted attribute") } if nKeysMain[0].Value.(*transaction.NotaryAssisted).NKeys == 0 { return errors.New("main transaction should have NKeys > 0") } if len(r.FallbackTransaction.Signers) != 2 { return errors.New("fallback transaction should have two signers") } if len(r.FallbackTransaction.Scripts[0].InvocationScript) != 66 || len(r.FallbackTransaction.Scripts[0].VerificationScript) != 0 || !bytes.HasPrefix(r.FallbackTransaction.Scripts[0].InvocationScript, []byte{byte(opcode.PUSHDATA1), keys.SignatureLen}) { return errors.New("fallback transaction has invalid dummy Notary witness") } if !r.FallbackTransaction.HasAttribute(transaction.NotValidBeforeT) { return errors.New("fallback transactions should have NotValidBefore attribute") } conflicts := r.FallbackTransaction.GetAttributes(transaction.ConflictsT) if len(conflicts) != 1 { return errors.New("fallback transaction should have one Conflicts attribute") } if conflicts[0].Value.(*transaction.Conflicts).Hash != r.MainTransaction.Hash() { return errors.New("fallback transaction does not conflict with the main transaction") } nKeysFallback := r.FallbackTransaction.GetAttributes(transaction.NotaryAssistedT) if len(nKeysFallback) == 0 { return errors.New("fallback transaction should have NotaryAssisted attribute") } if nKeysFallback[0].Value.(*transaction.NotaryAssisted).NKeys != 0 { return errors.New("fallback transaction should have NKeys = 0") } if r.MainTransaction.ValidUntilBlock != r.FallbackTransaction.ValidUntilBlock { return errors.New("both main and fallback transactions should have the same ValidUntil value") } return nil }