mirror of https://github.com/guggero/chantools
recoverloopin: add new command recoverloopin
This commit adds a new command recoverloopin which allows the user to recover stuck loop in funds.pull/66/head
sputn1ck
1 year ago
parent
aa767d3faa
commit
ab0743a3d3
@ -0,0 +1,336 @@
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package main
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import (
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"bytes"
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"encoding/hex"
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"fmt"
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"github.com/btcsuite/btcd/btcutil"
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"github.com/btcsuite/btcd/chaincfg/chainhash"
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"github.com/btcsuite/btcd/txscript"
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"github.com/btcsuite/btcd/wire"
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"github.com/guggero/chantools/btc"
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"github.com/guggero/chantools/lnd"
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"github.com/lightninglabs/loop"
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"github.com/lightninglabs/loop/loopdb"
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"github.com/lightninglabs/loop/swap"
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"github.com/lightningnetwork/lnd/input"
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"github.com/lightningnetwork/lnd/keychain"
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"github.com/lightningnetwork/lnd/lnwallet/chainfee"
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"github.com/spf13/cobra"
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)
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type recoverLoopInCommand struct {
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TxID string
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Vout uint32
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SwapHash string
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SweepAddr string
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FeeRate uint16
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StartKeyIndex int
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NumTries int
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APIURL string
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Publish bool
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LoopDbPath string
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rootKey *rootKey
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cmd *cobra.Command
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}
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func newRecoverLoopInCommand() *cobra.Command {
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cc := &recoverLoopInCommand{}
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cc.cmd = &cobra.Command{
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Use: "recoverloopin",
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Short: "Recover a loop in swap that the loop daemon " +
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"is not able to sweep",
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Example: `chantools recoverloopin \
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--txid abcdef01234... \
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--vout 0 \
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--swap_hash abcdef01234... \
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--loop_db_path /path/to/loop.db \
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--sweep_addr bc1pxxxxxxx \
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--feerate 10`,
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RunE: cc.Execute,
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}
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cc.cmd.Flags().StringVar(
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&cc.TxID, "txid", "", "transaction id of the on-chain "+
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"transaction that created the HTLC",
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)
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cc.cmd.Flags().Uint32Var(
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&cc.Vout, "vout", 0, "output index of the on-chain "+
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"transaction that created the HTLC",
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)
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cc.cmd.Flags().StringVar(
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&cc.SwapHash, "swap_hash", "", "swap hash of the loop in "+
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"swap",
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)
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cc.cmd.Flags().StringVar(
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&cc.LoopDbPath, "loop_db_path", "", "path to the loop "+
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"database file",
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)
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cc.cmd.Flags().StringVar(
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&cc.SweepAddr, "sweep_addr", "", "address to recover "+
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"the funds to",
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)
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cc.cmd.Flags().Uint16Var(
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&cc.FeeRate, "feerate", 0, "fee rate to "+
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"use for the sweep transaction in sat/vByte",
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)
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cc.cmd.Flags().IntVar(
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&cc.NumTries, "num_tries", 1000, "number of tries to "+
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"try to find the correct key index",
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)
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cc.cmd.Flags().IntVar(
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&cc.StartKeyIndex, "start_key_index", 0, "start key index "+
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"to try to find the correct key index",
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)
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cc.cmd.Flags().StringVar(
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&cc.APIURL, "apiurl", defaultAPIURL, "API URL to use (must "+
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"be esplora compatible)",
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)
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cc.cmd.Flags().BoolVar(
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&cc.Publish, "publish", false, "publish sweep TX to the chain "+
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"API instead of just printing the TX",
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)
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cc.rootKey = newRootKey(cc.cmd, "deriving starting key")
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return cc.cmd
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}
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func (c *recoverLoopInCommand) Execute(_ *cobra.Command, _ []string) error {
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extendedKey, err := c.rootKey.read()
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if err != nil {
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return fmt.Errorf("error reading root key: %w", err)
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}
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api := &btc.ExplorerAPI{BaseURL: c.APIURL}
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signer := &lnd.Signer{
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ExtendedKey: extendedKey,
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ChainParams: chainParams,
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}
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// Try to fetch the swap from the database.
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store, err := loopdb.NewBoltSwapStore(c.LoopDbPath, chainParams)
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if err != nil {
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return err
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}
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defer store.Close()
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swaps, err := store.FetchLoopInSwaps()
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if err != nil {
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return err
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}
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var loopIn *loopdb.LoopIn
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for _, s := range swaps {
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if s.Hash.String() == c.SwapHash {
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loopIn = s
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break
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}
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}
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if loopIn == nil {
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return fmt.Errorf("swap not found")
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}
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fmt.Println("Loop expires at block height", loopIn.Contract.CltvExpiry)
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// Get the swaps htlc.
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htlc, err := loop.GetHtlc(
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loopIn.Hash, &loopIn.Contract.SwapContract, chainParams,
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)
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if err != nil {
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return err
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}
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// Get the destination address.
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sweepAddr, err := btcutil.DecodeAddress(c.SweepAddr, chainParams)
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if err != nil {
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return err
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}
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// Calculate the sweep fee.
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estimator := &input.TxWeightEstimator{}
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err = htlc.AddTimeoutToEstimator(estimator)
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if err != nil {
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return err
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}
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switch sweepAddr.(type) {
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case *btcutil.AddressWitnessPubKeyHash:
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estimator.AddP2WKHOutput()
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case *btcutil.AddressTaproot:
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estimator.AddP2TROutput()
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default:
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return fmt.Errorf("unsupported address type")
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}
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feeRateKWeight := chainfee.SatPerKVByte(1000 * c.FeeRate).FeePerKWeight()
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fee := feeRateKWeight.FeeForWeight(int64(estimator.Weight()))
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txID, err := chainhash.NewHashFromStr(c.TxID)
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if err != nil {
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return err
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}
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// Get the htlc outpoint.
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htlcOutpoint := wire.OutPoint{
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Hash: *txID,
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Index: c.Vout,
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}
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// Compose tx.
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sweepTx := wire.NewMsgTx(2)
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sweepTx.LockTime = uint32(loopIn.Contract.CltvExpiry)
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// Add HTLC input.
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sweepTx.AddTxIn(&wire.TxIn{
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PreviousOutPoint: htlcOutpoint,
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Sequence: 0,
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})
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// Add output for the destination address.
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sweepPkScript, err := txscript.PayToAddrScript(sweepAddr)
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if err != nil {
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return err
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}
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sweepTx.AddTxOut(&wire.TxOut{
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PkScript: sweepPkScript,
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Value: int64(loopIn.Contract.AmountRequested) - int64(fee),
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})
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// If the htlc is version 2, we need to brute force the key locator, as
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// it is not stored in the database.
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var rawTx []byte
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if htlc.Version == swap.HtlcV2 {
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fmt.Println("Brute forcing key index...")
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for i := c.StartKeyIndex; i < c.StartKeyIndex+c.NumTries; i++ {
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rawTx, err = getSignedTx(
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signer, loopIn, sweepTx, htlc,
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keychain.KeyFamily(swap.KeyFamily), uint32(i),
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)
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if err == nil {
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break
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}
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}
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if rawTx == nil {
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return fmt.Errorf("failed to brute force key index, " +
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"please try again with a higher start key index")
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}
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} else {
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rawTx, err = getSignedTx(
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signer, loopIn, sweepTx, htlc,
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loopIn.Contract.HtlcKeys.ClientScriptKeyLocator.Family,
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loopIn.Contract.HtlcKeys.ClientScriptKeyLocator.Index,
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)
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if err != nil {
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return err
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}
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}
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// Publish TX.
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if c.Publish {
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response, err := api.PublishTx(
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hex.EncodeToString(rawTx),
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)
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if err != nil {
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return err
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}
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log.Infof("Published TX %s, response: %s",
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sweepTx.TxHash().String(), response)
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} else {
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fmt.Printf("Success, we successfully created the sweep transaction. "+
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"Please publish this using any bitcoin node:\n\n%x\n\n",
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rawTx)
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}
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return nil
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}
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func getSignedTx(signer *lnd.Signer, loopIn *loopdb.LoopIn, sweepTx *wire.MsgTx,
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htlc *swap.Htlc, keyFamily keychain.KeyFamily,
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keyIndex uint32) ([]byte, error) {
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// Create the sign descriptor.
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prevoutFetcher := txscript.NewCannedPrevOutputFetcher(
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htlc.PkScript, int64(loopIn.Contract.AmountRequested),
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)
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signDesc := &input.SignDescriptor{
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KeyDesc: keychain.KeyDescriptor{
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KeyLocator: keychain.KeyLocator{
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Family: keyFamily,
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Index: keyIndex,
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},
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},
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WitnessScript: htlc.TimeoutScript(),
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HashType: htlc.SigHash(),
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InputIndex: 0,
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PrevOutputFetcher: prevoutFetcher,
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Output: &wire.TxOut{
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PkScript: htlc.PkScript,
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Value: int64(loopIn.Contract.AmountRequested),
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},
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}
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switch htlc.Version {
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case swap.HtlcV2:
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signDesc.SignMethod = input.WitnessV0SignMethod
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case swap.HtlcV3:
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signDesc.SignMethod = input.TaprootScriptSpendSignMethod
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}
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sig, err := signer.SignOutputRaw(sweepTx, signDesc)
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if err != nil {
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return nil, err
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}
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witness, err := htlc.GenTimeoutWitness(sig.Serialize())
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if err != nil {
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return nil, err
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}
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sweepTx.TxIn[0].Witness = witness
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rawTx, err := encodeTx(sweepTx)
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if err != nil {
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return nil, err
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}
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sighashes := txscript.NewTxSigHashes(sweepTx, prevoutFetcher)
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// Verify the signature. This will throw an error if the signature is
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// invalid and allows us to bruteforce the key index.
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vm, err := txscript.NewEngine(
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htlc.PkScript, sweepTx, 0, txscript.StandardVerifyFlags, nil,
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sighashes, int64(loopIn.Contract.AmountRequested), prevoutFetcher,
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)
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if err != nil {
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return nil, err
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}
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err = vm.Execute()
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if err != nil {
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return nil, err
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}
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return rawTx, nil
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}
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// encodeTx encodes a tx to raw bytes.
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func encodeTx(tx *wire.MsgTx) ([]byte, error) {
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var buffer bytes.Buffer
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err := tx.BtcEncode(&buffer, 0, wire.WitnessEncoding)
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if err != nil {
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return nil, err
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}
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rawTx := buffer.Bytes()
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return rawTx, nil
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}
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