package wtwire import ( "encoding/binary" "fmt" "io" "github.com/btcsuite/btcd/btcec" "github.com/btcsuite/btcd/wire" "github.com/lightningnetwork/lnd/lnwallet" "github.com/lightningnetwork/lnd/watchtower/blob" ) // WriteElement is a one-stop shop to write the big endian representation of // any element which is to be serialized for the wire protocol. The passed // io.Writer should be backed by an appropriately sized byte slice, or be able // to dynamically expand to accommodate additional data. func WriteElement(w io.Writer, element interface{}) error { switch e := element.(type) { case uint8: var b [1]byte b[0] = e if _, err := w.Write(b[:]); err != nil { return err } case uint16: var b [2]byte binary.BigEndian.PutUint16(b[:], e) if _, err := w.Write(b[:]); err != nil { return err } case blob.Type: var b [2]byte binary.BigEndian.PutUint16(b[:], uint16(e)) if _, err := w.Write(b[:]); err != nil { return err } case uint32: var b [4]byte binary.BigEndian.PutUint32(b[:], e) if _, err := w.Write(b[:]); err != nil { return err } case uint64: var b [8]byte binary.BigEndian.PutUint64(b[:], e) if _, err := w.Write(b[:]); err != nil { return err } case [16]byte: if _, err := w.Write(e[:]); err != nil { return err } case [32]byte: if _, err := w.Write(e[:]); err != nil { return err } case [33]byte: if _, err := w.Write(e[:]); err != nil { return err } case []byte: if err := wire.WriteVarBytes(w, 0, e); err != nil { return err } case lnwallet.SatPerKWeight: var b [8]byte binary.BigEndian.PutUint64(b[:], uint64(e)) if _, err := w.Write(b[:]); err != nil { return err } case ErrorCode: var b [2]byte binary.BigEndian.PutUint16(b[:], uint16(e)) if _, err := w.Write(b[:]); err != nil { return err } case *btcec.PublicKey: if e == nil { return fmt.Errorf("cannot write nil pubkey") } var b [33]byte serializedPubkey := e.SerializeCompressed() copy(b[:], serializedPubkey) if _, err := w.Write(b[:]); err != nil { return err } default: return fmt.Errorf("Unknown type in WriteElement: %T", e) } return nil } // WriteElements is writes each element in the elements slice to the passed // io.Writer using WriteElement. func WriteElements(w io.Writer, elements ...interface{}) error { for _, element := range elements { err := WriteElement(w, element) if err != nil { return err } } return nil } // ReadElement is a one-stop utility function to deserialize any datastructure // encoded using the serialization format of lnwire. func ReadElement(r io.Reader, element interface{}) error { switch e := element.(type) { case *uint8: var b [1]uint8 if _, err := r.Read(b[:]); err != nil { return err } *e = b[0] case *uint16: var b [2]byte if _, err := io.ReadFull(r, b[:]); err != nil { return err } *e = binary.BigEndian.Uint16(b[:]) case *blob.Type: var b [2]byte if _, err := io.ReadFull(r, b[:]); err != nil { return err } *e = blob.Type(binary.BigEndian.Uint16(b[:])) case *uint32: var b [4]byte if _, err := io.ReadFull(r, b[:]); err != nil { return err } *e = binary.BigEndian.Uint32(b[:]) case *uint64: var b [8]byte if _, err := io.ReadFull(r, b[:]); err != nil { return err } *e = binary.BigEndian.Uint64(b[:]) case *[16]byte: if _, err := io.ReadFull(r, e[:]); err != nil { return err } case *[32]byte: if _, err := io.ReadFull(r, e[:]); err != nil { return err } case *[33]byte: if _, err := io.ReadFull(r, e[:]); err != nil { return err } case *[]byte: bytes, err := wire.ReadVarBytes(r, 0, 66000, "[]byte") if err != nil { return err } *e = bytes case *lnwallet.SatPerKWeight: var b [8]byte if _, err := io.ReadFull(r, b[:]); err != nil { return err } *e = lnwallet.SatPerKWeight(binary.BigEndian.Uint64(b[:])) case *ErrorCode: var b [2]byte if _, err := io.ReadFull(r, b[:]); err != nil { return err } *e = ErrorCode(binary.BigEndian.Uint16(b[:])) case **btcec.PublicKey: var b [btcec.PubKeyBytesLenCompressed]byte if _, err := io.ReadFull(r, b[:]); err != nil { return err } pubKey, err := btcec.ParsePubKey(b[:], btcec.S256()) if err != nil { return err } *e = pubKey default: return fmt.Errorf("Unknown type in ReadElement: %T", e) } return nil } // ReadElements deserializes a variable number of elements into the passed // io.Reader, with each element being deserialized according to the ReadElement // function. func ReadElements(r io.Reader, elements ...interface{}) error { for _, element := range elements { err := ReadElement(r, element) if err != nil { return err } } return nil }