lnd.xprv/lnwire/lnwire.go

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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?
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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.
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//
// "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.
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//
// 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 [][20]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 [20]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 *[][20]byte:
// How many to read
var sliceSize uint16
err = readElement(r, &sliceSize)
if err != nil {
return err
}
data := make([][20]byte, 0, sliceSize)
// Append the actual
for i := uint16(0); i < sliceSize; i++ {
var element [20]byte
err = readElement(r, &element)
if err != nil {
return err
}
data = append(data, element)
}
*e = data
case *[20]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
}
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(*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
}
(*e).Hash = *hash
// Index
var idxBytes [4]byte
_, err = io.ReadFull(r, idxBytes[:])
if err != nil {
return err
}
(*e).Index = binary.BigEndian.Uint32(idxBytes[:])
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
}