lnd.xprv/lnwire/lnwire.go

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package lnwire
import (
"bytes"
"encoding/binary"
"fmt"
"github.com/btcsuite/btcd/btcec"
"github.com/btcsuite/btcd/wire"
"github.com/btcsuite/btcutil"
"io"
"io/ioutil"
)
//Actual pkScript, not redeemScript
type PkScript []byte
//Subsatoshi amount
type MicroSatoshi int32
//Writes the big endian representation of element
//Unified function to call when writing different types
//Pre-allocate a byte-array of the correct size for cargo-cult security
//More copies but whatever...
func writeElement(w io.Writer, element interface{}) error {
var err error
switch e := element.(type) {
case uint8:
var b [1]byte
b[0] = byte(e)
_, err = w.Write(b[:])
if err != nil {
return err
}
return nil
case uint32:
var b [4]byte
binary.BigEndian.PutUint32(b[:], uint32(e))
_, err = w.Write(b[:])
if err != nil {
return err
}
return nil
case uint64:
var b [8]byte
binary.BigEndian.PutUint64(b[:], uint64(e))
_, err = w.Write(b[:])
if err != nil {
return err
}
return nil
case btcutil.Amount:
err = binary.Write(w, binary.BigEndian, int64(e))
if err != nil {
return err
}
return nil
case *btcec.PublicKey:
var b [33]byte
serializedPubkey := e.SerializeCompressed()
if len(serializedPubkey) != 33 {
return fmt.Errorf("Wrong size pubkey")
}
copy(b[:], serializedPubkey)
_, err = w.Write(b[:])
if err != nil {
return err
}
return nil
case []*btcec.Signature:
numSigs := len(e)
if numSigs > 127 {
return fmt.Errorf("Too many signatures!")
}
//Write the size
err = writeElement(w, uint8(numSigs))
if err != nil {
return err
}
//Write the data
for i := 0; i < numSigs; i++ {
err = writeElement(w, e[i])
if err != nil {
return err
}
}
return nil
case *btcec.Signature:
sig := e.Serialize()
sigLength := len(sig)
if sigLength > 73 {
return fmt.Errorf("Signature too long!")
}
//Write the size
err = writeElement(w, uint8(sigLength))
if err != nil {
return err
}
//Write the data
_, err = w.Write(sig)
if err != nil {
return err
}
return nil
case *wire.ShaHash:
_, err = w.Write(e[:])
if err != nil {
return err
}
return nil
case [20]byte:
_, err = w.Write(e[:])
if err != nil {
return err
}
return nil
case wire.BitcoinNet:
var b [4]byte
binary.BigEndian.PutUint32(b[:], uint32(e))
_, err := w.Write(b[:])
if err != nil {
return err
}
return nil
case PkScript:
scriptLength := len(e)
//Make sure it's P2PKH or P2SH size or less
if scriptLength > 25 {
return fmt.Errorf("PkScript too long!")
}
//Write the size (1-byte)
err = writeElement(w, uint8(scriptLength))
if err != nil {
return err
}
//Write the data
_, err = w.Write(e)
if err != nil {
return err
}
return nil
case []*wire.TxIn:
//Append the unsigned(!!!) txins
//Write the size (1-byte)
if len(e) > 127 {
return fmt.Errorf("Too many txins")
}
err = writeElement(w, uint8(len(e)))
if err != nil {
return err
}
//Append the actual TxIns (Size: NumOfTxins * 36)
//Do not include the sequence number to eliminate funny business
for _, in := range e {
err = writeElement(w, in)
if err != nil {
return err
}
}
return nil
case *wire.TxIn:
//Hash
var h [32]byte
copy(h[:], e.PreviousOutPoint.Hash.Bytes())
_, err = w.Write(h[:])
if err != nil {
return err
}
//Index
var idx [4]byte
binary.BigEndian.PutUint32(idx[:], e.PreviousOutPoint.Index)
_, err = w.Write(idx[:])
if err != nil {
return err
}
return nil
default:
return fmt.Errorf("Unknown type in writeElement: %T", e)
}
return nil
}
func writeElements(w io.Writer, elements ...interface{}) error {
for _, element := range elements {
err := writeElement(w, element)
if err != nil {
return err
}
}
return nil
}
func readElement(r io.Reader, element interface{}) error {
var err error
switch e := element.(type) {
case *uint8:
var b [1]uint8
_, err = r.Read(b[:])
if err != nil {
return err
}
*e = b[0]
return nil
case *uint32:
var b [4]byte
_, err = io.ReadFull(r, b[:])
if err != nil {
return err
}
*e = binary.BigEndian.Uint32(b[:])
return nil
case *uint64:
var b [8]byte
_, err = io.ReadFull(r, b[:])
if err != nil {
return err
}
*e = binary.BigEndian.Uint64(b[:])
return nil
case *btcutil.Amount:
var b [8]byte
_, err = io.ReadFull(r, b[:])
if err != nil {
return err
}
*e = btcutil.Amount(int64(binary.BigEndian.Uint64(b[:])))
return nil
case **wire.ShaHash:
var b wire.ShaHash
_, err = io.ReadFull(r, b[:])
if err != nil {
return err
}
*e = &b
return nil
case **btcec.PublicKey:
var b [33]byte
_, err = io.ReadFull(r, b[:])
if err != nil {
return err
}
x, err := btcec.ParsePubKey(b[:], btcec.S256())
if err != nil {
return err
}
*e = &*x
return nil
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:
var sigLength uint8
err = readElement(r, &sigLength)
if err != nil {
return err
}
if sigLength > 73 {
return fmt.Errorf("Signature too long!")
}
//Read the sig length
l := io.LimitReader(r, int64(sigLength))
sig, err := ioutil.ReadAll(l)
if err != nil {
return err
}
if len(sig) != int(sigLength) {
return fmt.Errorf("EOF: Signature length mismatch.")
}
btcecSig, err := btcec.ParseSignature(sig, btcec.S256())
if err != nil {
return err
}
*e = &*btcecSig
return nil
case *[20]byte:
_, err = io.ReadFull(r, e[:])
if err != nil {
return err
}
return nil
case *wire.BitcoinNet:
var b [4]byte
_, err := io.ReadFull(r, b[:])
if err != nil {
return err
}
*e = wire.BitcoinNet(binary.BigEndian.Uint32(b[:]))
return nil
case *PkScript:
//Get the script length first
var scriptLength uint8
err = readElement(r, &scriptLength)
if err != nil {
return err
}
if scriptLength > 25 {
return fmt.Errorf("PkScript too long!")
}
//Read the script length
l := io.LimitReader(r, int64(scriptLength))
*e, err = ioutil.ReadAll(l)
if len(*e) != int(scriptLength) {
return fmt.Errorf("EOF: Signature length mismatch.")
}
if err != nil {
return err
}
return nil
case *[]*wire.TxIn:
//Read the size (1-byte number of txins)
var numScripts uint8
err = readElement(r, &numScripts)
if err != nil {
return err
}
if numScripts > 127 {
return fmt.Errorf("Too many txins")
}
//Append the actual TxIns
var txins []*wire.TxIn
for i := uint8(0); i < numScripts; i++ {
outpoint := new(wire.OutPoint)
txin := wire.NewTxIn(outpoint, nil)
err = readElement(r, &txin)
if err != nil {
return err
}
txins = append(txins, txin)
}
*e = *&txins
return nil
case **wire.TxIn:
//Hash
var h [32]byte
_, err = io.ReadFull(r, h[:])
if err != nil {
return err
}
hash, err := wire.NewShaHash(h[:])
(*e).PreviousOutPoint.Hash = *hash
if err != nil {
return err
}
//Index
var idxBytes [4]byte
_, err = io.ReadFull(r, idxBytes[:])
if err != nil {
return err
}
(*e).PreviousOutPoint.Index = binary.BigEndian.Uint32(idxBytes[:])
return nil
default:
return fmt.Errorf("Unknown type in readElement: %T", e)
}
return nil
}
func readElements(r io.Reader, elements ...interface{}) error {
for _, element := range elements {
err := readElement(r, element)
if err != nil {
return err
}
}
return nil
}
//Validates whether a PkScript byte array is P2SH or P2PKH
func ValidatePkScript(pkScript PkScript) error {
if &pkScript == nil {
return fmt.Errorf("PkScript should not be empty!")
}
if len(pkScript) == 25 {
//P2PKH
//Begins with OP_DUP OP_HASH160 PUSHDATA(20)
if !bytes.Equal(pkScript[0:3], []byte{118, 169, 20}) ||
//Ends with OP_EQUALVERIFY OP_CHECKSIG
!bytes.Equal(pkScript[23:25], []byte{136, 172}) {
//If it's not correct, return error
return fmt.Errorf("PkScript only allows P2SH or P2PKH")
}
} else if len(pkScript) == 23 {
//P2SH
//Begins with OP_HASH160 PUSHDATA(20)
if !bytes.Equal(pkScript[0:2], []byte{169, 20}) ||
//Ends with OP_EQUAL
!bytes.Equal(pkScript[22:23], []byte{135}) {
//If it's not correct, return error
return fmt.Errorf("PkScript only allows P2SH or P2PKH")
}
} else {
//Length not 23 or 25
return fmt.Errorf("PkScript only allows P2SH or P2PKH")
}
return nil
}