package lnwire import ( "bytes" "encoding/binary" "fmt" "io" "github.com/roasbeef/btcd/btcec" "github.com/roasbeef/btcd/txscript" "github.com/roasbeef/btcd/wire" "github.com/roasbeef/btcutil" ) // MaxSliceLength is the maximum allowed lenth for any opaque byte slices in // the wire protocol. const MaxSliceLength = 65535 // PkScript is simple type definition which represents a raw serialized public // key script. type PkScript []byte // HTLCKey is an identifier used to uniquely identify any HTLC's transmitted // between Alice and Bob. In order to cancel, timeout, or settle HTLC's this // identifier should be used to allow either side to easily locate and modify // any staged or pending HTLCs. // TODO(roasbeef): change to HTLCIdentifier? type HTLCKey int64 // CommitHeight is an integer which represents the highest HTLCKey seen by // either side within their commitment transaction. Any addition to the pending, // HTLC lists on either side will increment this height. As a result this value // should always be monotonically increasing. Any CommitSignature or // CommitRevocation messages will reference a value for the commitment height // up to which it covers. HTLC's are only explicltly excluded by sending // HTLCReject messages referencing a particular HTLCKey. type CommitHeight uint64 // CreditsAmount are the native currency unit used within the Lightning Network. // Credits are denominated in sub-satoshi amounts, so micro-satoshis (1/1000). // This value is purposefully signed in order to allow the expression of negative // fees. // // "In any science-fiction movie, anywhere in the galaxy, currency is referred // to as 'credits.'" // --Sam Humphries. Ebert, Roger (1999). Ebert's bigger little movie // glossary. Andrews McMeel. p. 172. // // https://en.wikipedia.org/wiki/List_of_fictional_currencies // https://en.wikipedia.org/wiki/Fictional_currency#Trends_in_the_use_of_fictional_currencies // http://tvtropes.org/pmwiki/pmwiki.php/Main/WeWillSpendCreditsInTheFuture // US Display format: 1 BTC = 100,000,000'000 XCB // Or in BTC = 1.00000000'000 // Credits (XCB, accountants should use XCB :^) type CreditsAmount int64 // ToSatoshi converts an amount in Credits to the coresponding amount // expressed in Satoshis. // // NOTE: This function rounds down by default (floor). func (c CreditsAmount) ToSatoshi() int64 { return int64(c / 1000) } // 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 appropriatly sized byte slice, or be able // to dynamically expand to accomdate additional data. // // TODO(roasbeef): this should eventually draw from a buffer pool for // serialization. // TODO(roasbeef): switch to var-ints for all? func writeElement(w io.Writer, element interface{}) error { switch e := element.(type) { case uint8: var b [1]byte b[0] = byte(e) if _, err := w.Write(b[:]); err != nil { return err } case uint16: var b [2]byte binary.BigEndian.PutUint16(b[:], uint16(e)) if _, err := w.Write(b[:]); err != nil { return err } case CreditsAmount: if err := binary.Write(w, binary.BigEndian, int64(e)); err != nil { return err } case uint32: var b [4]byte binary.BigEndian.PutUint32(b[:], uint32(e)) if _, err := w.Write(b[:]); err != nil { return err } case uint64: var b [8]byte binary.BigEndian.PutUint64(b[:], uint64(e)) if _, err := w.Write(b[:]); err != nil { return err } case HTLCKey: if err := binary.Write(w, binary.BigEndian, int64(e)); err != nil { return err } case btcutil.Amount: if err := binary.Write(w, binary.BigEndian, int64(e)); err != nil { return err } case *btcec.PublicKey: var b [33]byte serializedPubkey := e.SerializeCompressed() copy(b[:], serializedPubkey) // TODO(roasbeef): use WriteVarBytes here? if _, err := w.Write(b[:]); err != nil { return err } case []uint64: // Enforce a max number of elements in a uint64 slice. numItems := len(e) if numItems > 65535 { return fmt.Errorf("Too many []uint64s") } // First write out the the number of elements in the slice as a // length prefix. if err := writeElement(w, uint16(numItems)); err != nil { return err } // After the prefix detailing the number of elements, write out // each uint64 in series. for i := 0; i < numItems; i++ { if err := writeElement(w, e[i]); err != nil { return err } } case []*btcec.Signature: // Enforce a sane number for the maximum number of signatures. numSigs := len(e) if numSigs > 127 { return fmt.Errorf("Too many signatures!") } // First write out the the number of elements in the slice as a // length prefix. if err := writeElement(w, uint8(numSigs)); err != nil { return err } // After the prefix detailing the number of elements, write out // each signature in series. for i := 0; i < numSigs; i++ { if err := writeElement(w, e[i]); err != nil { return err } } case *btcec.Signature: sig := e.Serialize() if len(sig) > 73 { return fmt.Errorf("Signature too long!") } if err := wire.WriteVarBytes(w, 0, sig); err != nil { return err } case *wire.ShaHash: if _, err := w.Write(e[:]); err != nil { return err } case [][32]byte: // First write out the number of elements in the slice. sliceSize := len(e) if err := writeElement(w, uint16(sliceSize)); err != nil { return err } // Then write each out sequentially. for _, element := range e { if err := writeElement(w, element); err != nil { return err } } case [32]byte: // TODO(roasbeef): should be factor out to caller logic... if _, err := w.Write(e[:]); err != nil { return err } case wire.BitcoinNet: var b [4]byte binary.BigEndian.PutUint32(b[:], uint32(e)) if _, err := w.Write(b[:]); err != nil { return err } case []byte: // Enforce the maxmium length of all slices used in the wire // protocol. sliceLength := len(e) if sliceLength > MaxSliceLength { return fmt.Errorf("Slice length too long!") } if err := wire.WriteVarBytes(w, 0, e); err != nil { return err } case PkScript: // Make sure it's P2PKH or P2SH size or less. scriptLength := len(e) if scriptLength > 25 { return fmt.Errorf("PkScript too long!") } if err := wire.WriteVarBytes(w, 0, e); err != nil { return err } case string: strlen := len(e) if strlen > MaxSliceLength { return fmt.Errorf("String too long!") } if err := wire.WriteVarString(w, 0, e); err != nil { return err } case []*wire.TxIn: // Write the size (1-byte) if len(e) > 127 { return fmt.Errorf("Too many txins") } // Write out the number of txins. if err := writeElement(w, uint8(len(e))); err != nil { return err } // Append the actual TxIns (Size: NumOfTxins * 36) // During serialization we leave out the sequence number to // eliminate any funny business. for _, in := range e { if err := writeElement(w, in); err != nil { return err } } case *wire.TxIn: // First write out the previous txid. var h [32]byte copy(h[:], e.PreviousOutPoint.Hash[:]) if _, err := w.Write(h[:]); err != nil { return err } // Then the exact index of the previous out point. var idx [4]byte binary.BigEndian.PutUint32(idx[:], e.PreviousOutPoint.Index) if _, err := w.Write(idx[:]); err != nil { return err } case *wire.OutPoint: // TODO(roasbeef): consolidate with above // First write out the previous txid. var h [32]byte copy(h[:], e.Hash[:]) if _, err := w.Write(h[:]); err != nil { return err } // Then the exact index of this output. var idx [4]byte binary.BigEndian.PutUint32(idx[:], e.Index) if _, err := w.Write(idx[:]); err != nil { return err } // TODO(roasbeef): *MsgTx 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 { var err 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 *CreditsAmount: var b [8]byte if _, err := io.ReadFull(r, b[:]); err != nil { return err } *e = CreditsAmount(int64(binary.BigEndian.Uint64(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 *HTLCKey: var b [8]byte if _, err := io.ReadFull(r, b[:]); err != nil { return err } *e = HTLCKey(int64(binary.BigEndian.Uint64(b[:]))) case *btcutil.Amount: var b [8]byte if _, err := io.ReadFull(r, b[:]); err != nil { return err } *e = btcutil.Amount(int64(binary.BigEndian.Uint64(b[:]))) case **wire.ShaHash: var b wire.ShaHash if _, err := io.ReadFull(r, b[:]); err != nil { return err } *e = &b case **btcec.PublicKey: var b [33]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 case *[]uint64: var numItems uint16 if err := readElement(r, &numItems); err != nil { return err } // if numItems > 65535 { // return fmt.Errorf("Too many items in []uint64") // } // Read the number of items var items []uint64 for i := uint16(0); i < numItems; i++ { var item uint64 err = readElement(r, &item) if err != nil { return err } items = append(items, item) } *e = items case *[]*btcec.Signature: var numSigs uint8 err = readElement(r, &numSigs) if err != nil { return err } if numSigs > 127 { return fmt.Errorf("Too many signatures!") } // Read that number of signatures var sigs []*btcec.Signature for i := uint8(0); i < numSigs; i++ { sig := new(btcec.Signature) err = readElement(r, &sig) if err != nil { return err } sigs = append(sigs, sig) } *e = sigs return nil case **btcec.Signature: sigBytes, err := wire.ReadVarBytes(r, 0, 73, "signature") if err != nil { return err } sig, err := btcec.ParseSignature(sigBytes, btcec.S256()) if err != nil { return err } *e = sig case *[][32]byte: // How many to read var sliceSize uint16 err = readElement(r, &sliceSize) if err != nil { return err } data := make([][32]byte, 0, sliceSize) // Append the actual for i := uint16(0); i < sliceSize; i++ { var element [32]byte err = readElement(r, &element) if err != nil { return err } data = append(data, element) } *e = data case *[32]byte: if _, err = io.ReadFull(r, e[:]); err != nil { return err } case *wire.BitcoinNet: var b [4]byte if _, err := io.ReadFull(r, b[:]); err != nil { return err } *e = wire.BitcoinNet(binary.BigEndian.Uint32(b[:])) return nil case *[]byte: bytes, err := wire.ReadVarBytes(r, 0, MaxSliceLength, "byte slice") if err != nil { return err } *e = bytes case *PkScript: pkScript, err := wire.ReadVarBytes(r, 0, 25, "pkscript") if err != nil { return err } *e = pkScript case *string: str, err := wire.ReadVarString(r, 0) if err != nil { return err } *e = str case *[]*wire.TxIn: // Read the size (1-byte number of txins) var numScripts uint8 if err := readElement(r, &numScripts); err != nil { return err } if numScripts > 127 { return fmt.Errorf("Too many txins") } // Append the actual TxIns txins := make([]*wire.TxIn, 0, numScripts) for i := uint8(0); i < numScripts; i++ { outpoint := new(wire.OutPoint) txin := wire.NewTxIn(outpoint, nil, nil) if err := readElement(r, &txin); err != nil { return err } txins = append(txins, txin) } *e = txins case **wire.TxIn: // Hash var h [32]byte if _, err = io.ReadFull(r, h[:]); err != nil { return err } hash, err := wire.NewShaHash(h[:]) if err != nil { return err } (*e).PreviousOutPoint.Hash = *hash // Index var idxBytes [4]byte _, err = io.ReadFull(r, idxBytes[:]) if err != nil { return err } (*e).PreviousOutPoint.Index = binary.BigEndian.Uint32(idxBytes[:]) return nil case **wire.OutPoint: // TODO(roasbeef): consolidate with above var h [32]byte if _, err = io.ReadFull(r, h[:]); err != nil { return err } hash, err := wire.NewShaHash(h[:]) if err != nil { return err } // Index var idxBytes [4]byte _, err = io.ReadFull(r, idxBytes[:]) if err != nil { return err } index := binary.BigEndian.Uint32(idxBytes[:]) *e = wire.NewOutPoint(hash, index) 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 } // validatePkScript determines if the passed pkScript is a valid pkScript within // lnwire. The only pkScript templates that lnwire currently allows are: // P2SH, P2WSH, P2PKH, and P2WKH. func isValidPkScript(pkScript PkScript) bool { // A nil pkScript is obviously invalid. if pkScript == nil { return false } switch len(pkScript) { case 25: // A valid p2pkh script must be exactly 25 bytes. It must begin // with the define prefix, and end with the define suffix. p2pkhPrefix := []byte{txscript.OP_DUP, txscript.OP_HASH160} p2pkhSuffix := []byte{txscript.OP_EQUALVERIFY, txscript.OP_CHECKSIG, txscript.OP_DATA_20} if !bytes.Equal(pkScript[0:3], p2pkhPrefix) || !bytes.Equal(pkScript[23:25], p2pkhSuffix) { return false } case 22: // P2WKH // A valid P2WKH script must be exactly 22 bytes, with the first // two op codes being an OP_0 marking a version zero witness // program, and the second byte being a 20 byte push data. if pkScript[0] != txscript.OP_0 || pkScript[1] != txscript.OP_DATA_20 { return false } case 23: // A valid P2SH script must begin with OP_HASH160 PUSHDATA(20), // contain 20 bytes, then end with an OP_EQUAL. p2shPrefix := []byte{txscript.OP_HASH160, txscript.OP_DATA_20} p2shSuffix := []byte{txscript.OP_EQUAL} if !bytes.Equal(pkScript[0:2], p2shPrefix) || !bytes.Equal(pkScript[22:23], p2shSuffix) { return false } case 34: // A P2WSH script must be exactly 34 bytes, with the first two // op codes being an OP_0 marking a version zero witness program, // and the second byte being a 32 byte push data. if pkScript[0] != txscript.OP_0 || pkScript[1] != txscript.OP_DATA_32 { return false } default: return false } return true }