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submarineswap.go
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submarineswap.go
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package main
import (
"crypto/sha256"
"crypto/x509"
"errors"
"log"
"net"
"os"
"strings"
"swapper/mempoolspace"
"github.com/btcsuite/btcd/btcec"
"github.com/btcsuite/btcd/chaincfg"
"github.com/btcsuite/btcd/txscript"
"github.com/btcsuite/btcd/wire"
"github.com/btcsuite/btcutil"
"github.com/lightningnetwork/lnd/input"
"github.com/lightningnetwork/lnd/lnwallet/chainfee"
"google.golang.org/grpc"
"google.golang.org/grpc/credentials"
)
const (
defaultLockHeight = 288
redeemWitnessInputSize = 1 + 1 + 73 + 1 + 32 + 1 + 100
)
func generateSubmarineSwapScript(swapperPubKey, payerPubKey, hash []byte, lockHeight int64) ([]byte, error) {
builder := txscript.NewScriptBuilder()
builder.AddOp(txscript.OP_HASH160)
builder.AddData(input.Ripemd160H(hash))
builder.AddOp(txscript.OP_EQUAL) // Leaves 0P1 (true) on the stack if preimage matches
builder.AddOp(txscript.OP_IF)
builder.AddData(swapperPubKey) // Path taken if preimage matches
builder.AddOp(txscript.OP_ELSE)
builder.AddInt64(lockHeight)
builder.AddOp(txscript.OP_CHECKSEQUENCEVERIFY)
builder.AddOp(txscript.OP_DROP)
builder.AddData(payerPubKey) // Refund back to payer
builder.AddOp(txscript.OP_ENDIF)
builder.AddOp(txscript.OP_CHECKSIG)
return builder.Script()
}
func NewSubmarineSwap(net *chaincfg.Params, pubKey, hash []byte) (address btcutil.Address, script, swapperPubKey []byte, lockHeight int64, err error) {
if len(pubKey) != btcec.PubKeyBytesLenCompressed {
err = errors.New("pubKey not valid")
return
}
if len(hash) != 32 {
err = errors.New("hash not valid")
return
}
//Need to check that the hash doesn't already exists in our db
_, _, _, _, errGet := getSwapperSubmarineData(hash)
if errGet == nil {
err = errors.New("Hash already exists")
return
}
//Create swapperKey and swapperPubKey
key, err := btcec.NewPrivateKey(btcec.S256())
if err != nil {
return
}
swapperKey := key.Serialize()
swapperPubKey = key.PubKey().SerializeCompressed()
lockHeight = defaultLockHeight
//Create the script
script, err = generateSubmarineSwapScript(swapperPubKey, pubKey, hash, defaultLockHeight)
if err != nil {
return
}
address, err = newAddressWitnessScriptHash(script, net)
if err != nil {
return
}
//Need to save the data into postgres
err = saveSwapperSubmarineData(net.ScriptHashAddrID, hash, lockHeight, swapperKey, script)
return
}
func newAddressWitnessScriptHash(script []byte, net *chaincfg.Params) (*btcutil.AddressWitnessScriptHash, error) {
witnessProg := sha256.Sum256(script)
return btcutil.NewAddressWitnessScriptHash(witnessProg[:], net)
}
func redeemFees(net *chaincfg.Params, hash []byte, feePerKw chainfee.SatPerKWeight) (btcutil.Amount, error) {
c := &mempoolspace.Client{baseUrl: "https://mempool.space/api"}
utxos, err := c.GetUtxos(hash)
if err != nil {
return 0, err
}
if len(utxos) == 0 {
return 0, errors.New("no utxo")
}
redeemTx := wire.NewMsgTx(1)
// Add the inputs without the witness and calculate the amount to redeem
var amount btcutil.Amount
for _, utxo := range utxos {
amount += utxo.Value
txIn := wire.NewTxIn(&utxo.OutPoint, nil, nil)
txIn.Sequence = 0
redeemTx.AddTxIn(txIn)
}
//Generate a random address
privateKey, err := btcec.NewPrivateKey(btcec.S256())
if err != nil {
return 0, err
}
redeemAddress, err := btcutil.NewAddressPubKey(privateKey.PubKey().SerializeCompressed(), net)
if err != nil {
return 0, err
}
// Add the single output
redeemScript, err := txscript.PayToAddrScript(redeemAddress)
if err != nil {
return 0, err
}
txOut := wire.TxOut{PkScript: redeemScript}
redeemTx.AddTxOut(&txOut)
currentHeight, err := c.CurrentHeight()
if err != nil {
return 0, err
}
redeemTx.LockTime = uint32(currentHeight)
// Calcluate the weight and the fee
weight := 4*redeemTx.SerializeSizeStripped() + redeemWitnessInputSize*len(redeemTx.TxIn)
// Adjust the amount in the txout
return feePerKw.FeeForWeight(int64(weight)), nil
}
// Redeem
func redeem(net *chaincfg.Params, preimage []byte, redeemAddress btcutil.Address, feePerKw chainfee.SatPerKWeight) (*wire.MsgTx, error) {
c := &mempoolspace.Client{baseUrl: "https://mempool.space/api"}
hash := sha256.Sum256(preimage)
_, serviceKey, script, err := getSwapperSubmarineData(net.ScriptHashAddrID, hash[:])
if err != nil {
return nil, err
}
utxos, err := c.GetUtxos(hash)
if err != nil {
return 0, err
}
if len(utxos) == 0 {
return 0, errors.New("no utxo")
}
redeemTx := wire.NewMsgTx(1)
// Add the inputs without the witness and calculate the amount to redeem
var amount btcutil.Amount
for _, utxo := range utxos {
amount += utxo.Value
txIn := wire.NewTxIn(&utxo.OutPoint, nil, nil)
txIn.Sequence = 0
redeemTx.AddTxIn(txIn)
}
// Add the single output
redeemScript, err := txscript.PayToAddrScript(redeemAddress)
if err != nil {
return nil, err
}
txOut := wire.TxOut{PkScript: redeemScript}
redeemTx.AddTxOut(&txOut)
currentHeight, err := c.CurrentHeight()
if err != nil {
return 0, err
}
redeemTx.LockTime = uint32(currentHeight)
// Calcluate the weight and the fee
weight := 4*redeemTx.SerializeSizeStripped() + redeemWitnessInputSize*len(redeemTx.TxIn)
// Adjust the amount in the txout
redeemTx.TxOut[0].Value = int64(amount - feePerKw.FeeForWeight(int64(weight)))
sigHashes := txscript.NewTxSigHashes(redeemTx)
privateKey, _ := btcec.PrivKeyFromBytes(btcec.S256(), serviceKey)
for idx := range redeemTx.TxIn {
scriptSig, err := txscript.RawTxInWitnessSignature(redeemTx, sigHashes, idx, int64(utxos[idx].Value), script, txscript.SigHashAll, privateKey)
if err != nil {
return nil, err
}
redeemTx.TxIn[idx].Witness = [][]byte{scriptSig, preimage, script}
}
err = c.BroadcastTransaction(redeemTx)
if err != nil {
return nil, err
}
return redeemTx, nil
}
func subSwapServiceRedeemFees(ActiveNetParams *chaincfg.Params, hash []byte) (int64, error) {
c := &mempoolspace.Client{baseUrl: "https://mempool.space/api"}
fee, err := c.RecommendedFee()
feePerKw, err := chainfee.SatPerKVByte(fee * 1000).FeePerKWeight()
if err != nil {
return 0, err
}
amount, err := redeemFees(ActiveNetParams, hash, feePerKw)
if err != nil {
return 0, err
}
return int64(amount), nil
}
func subSwapServiceRedeem(ActiveNetParams *chaincfg.Params, hash []byte, preimage []byte, redeemAddress btcutil.Address) ([]byte, error) {
c := &mempoolspace.Client{baseUrl: "https://mempool.space/api"}
fee, err := c.RecommendedFee()
feePerKw, err := chainfee.SatPerKVByte(fee * 1000).FeePerKWeight()
if err != nil {
return nil, err
}
tx, err := redeem(
ActiveNetParams,
preimage,
redeemAddress,
feePerKw,
)
if err != nil {
return nil, err
}
log.Infof("[subswapserviceredeem] txid: %v", tx.TxHash().String())
return tx.TxHash().String(), nil
}
func main() {
err := pgConnect()
if err != nil {
log.Fatalf("pgConnect() error: %v", err)
}
address := os.Getenv("LISTEN_ADDRESS")
var lis net.Listener
lis, err = net.Listen("tcp", address)
if err != nil {
log.Fatalf("failed to listen: %v", err)
}
// Creds file to connect to gRPC
cp := x509.NewCertPool()
if !cp.AppendCertsFromPEM([]byte(strings.Replace(os.Getenv("CERT"), "\\n", "\n", -1))) {
log.Fatalf("credentials: failed to append certificates")
}
creds := credentials.NewClientTLSFromCert(cp, "")
conn, err := grpc.Dial(os.Getenv("ADDRESS"), grpc.WithTransportCredentials(creds))
if err != nil {
log.Fatalf("Failed to connect to gRPC: %v", err)
}
defer conn.Close()
var opts []grpc.ServerOption
s := grpc.NewServer(opts...)
if err := s.Serve(lis); err != nil {
log.Fatalf("failed to serve: %v", err)
}
}