mirror of https://github.com/guggero/chantools
Add forceclose command
Oliver Gugger
5 years ago
parent
6949457997
commit
a2114a28f4
@ -0,0 +1,253 @@
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package chantools
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import (
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"bytes"
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"encoding/hex"
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"encoding/json"
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"fmt"
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"io"
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"io/ioutil"
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"time"
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"github.com/btcsuite/btcd/btcec"
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"github.com/btcsuite/btcd/txscript"
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"github.com/btcsuite/btcd/wire"
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"github.com/btcsuite/btcutil/hdkeychain"
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"github.com/lightningnetwork/lnd/channeldb"
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"github.com/lightningnetwork/lnd/input"
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"github.com/lightningnetwork/lnd/keychain"
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)
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func forceCloseChannels(cfg *config, entries []*SummaryEntry,
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chanDb *channeldb.DB, publish bool) error {
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channels, err := chanDb.FetchAllChannels()
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if err != nil {
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return err
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}
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chainApi := &chainApi{baseUrl:cfg.ApiUrl}
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extendedKey, err := hdkeychain.NewKeyFromString(cfg.RootKey)
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if err != nil {
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return err
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}
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signer := &signer{extendedKey: extendedKey}
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// Go through all channels in the DB, find the still open ones and
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// publish their local commitment TX.
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for _, channel := range channels {
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channelPoint := channel.FundingOutpoint.String()
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var channelEntry *SummaryEntry
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for _, entry := range entries {
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if entry.ChannelPoint == channelPoint {
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channelEntry = entry
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}
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}
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// Don't try anything with closed channels.
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if channelEntry == nil || channelEntry.ClosingTX != nil {
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continue
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}
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localCommit := channel.LocalCommitment
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localCommitTx := localCommit.CommitTx
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if localCommitTx == nil {
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log.Errorf("Cannot force-close, no local commit TX for "+
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"channel %s", channelEntry.ChannelPoint)
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continue
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}
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// Create signed transaction.
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lc := &LightningChannel{
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localChanCfg: channel.LocalChanCfg,
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remoteChanCfg: channel.RemoteChanCfg,
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channelState: channel,
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txSigner: signer,
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}
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err := lc.createSignDesc()
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if err != nil {
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return err
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}
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// Serialize transaction.
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signedTx, err := lc.getSignedCommitTx()
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if err != nil {
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return err
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}
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var buf bytes.Buffer
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err = signedTx.Serialize(io.Writer(&buf))
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if err != nil {
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return err
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}
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hash := signedTx.TxHash()
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serialized := hex.EncodeToString(buf.Bytes())
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// Calculate commit point.
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basepoint := channel.LocalChanCfg.DelayBasePoint
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revocationPreimage, err := channel.RevocationProducer.AtIndex(
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localCommit.CommitHeight,
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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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point := input.ComputeCommitmentPoint(revocationPreimage[:])
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channelEntry.ForceClose = &ForceClose{
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TXID: hash.String(),
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Serialized: serialized,
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DelayBasepoint: &Basepoint{
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Family: uint16(basepoint.Family),
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Index: basepoint.Index,
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},
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CommitPoint: hex.EncodeToString(
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point.SerializeCompressed(),
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),
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Outs: make([]*Out, len(localCommitTx.TxOut)),
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}
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for idx, out := range localCommitTx.TxOut {
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script, err := txscript.DisasmString(out.PkScript)
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if err != nil {
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return err
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}
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channelEntry.ForceClose.Outs[idx] = &Out{
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Script: hex.EncodeToString(out.PkScript),
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ScriptAsm: script,
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Value: uint64(out.Value),
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}
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}
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// Publish TX.
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if publish {
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response, err := chainApi.PublishTx(serialized)
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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", hash.String(),
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response)
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}
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}
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summaryBytes, err := json.MarshalIndent(&SummaryEntryFile{
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Channels: entries,
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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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fileName := fmt.Sprintf("results/forceclose-%s.json",
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time.Now().Format("2006-01-02-15-04-05"))
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log.Infof("Writing result to %s", fileName)
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return ioutil.WriteFile(fileName, summaryBytes, 0644)
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}
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type signer struct {
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extendedKey *hdkeychain.ExtendedKey
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}
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func (s *signer) SignOutputRaw(tx *wire.MsgTx,
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signDesc *input.SignDescriptor) ([]byte, error) {
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witnessScript := signDesc.WitnessScript
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// First attempt to fetch the private key which corresponds to the
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// specified public key.
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privKey, err := s.fetchPrivKey(&signDesc.KeyDesc)
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if err != nil {
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return nil, err
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}
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amt := signDesc.Output.Value
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sig, err := txscript.RawTxInWitnessSignature(
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tx, signDesc.SigHashes, signDesc.InputIndex, amt,
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witnessScript, signDesc.HashType, privKey,
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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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// Chop off the sighash flag at the end of the signature.
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return sig[:len(sig)-1], nil
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}
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func (s *signer) fetchPrivKey(descriptor *keychain.KeyDescriptor) (
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*btcec.PrivateKey, error) {
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key, err := deriveChildren(s.extendedKey, []uint32{
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hardenedKeyStart + uint32(keychain.BIP0043Purpose),
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hardenedKeyStart + chainParams.HDCoinType,
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hardenedKeyStart + uint32(descriptor.Family),
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0,
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descriptor.Index,
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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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return key.ECPrivKey()
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}
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type LightningChannel struct {
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localChanCfg channeldb.ChannelConfig
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remoteChanCfg channeldb.ChannelConfig
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signDesc *input.SignDescriptor
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channelState *channeldb.OpenChannel
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txSigner *signer
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}
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// createSignDesc derives the SignDescriptor for commitment transactions from
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// other fields on the LightningChannel.
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func (lc *LightningChannel) createSignDesc() error {
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localKey := lc.localChanCfg.MultiSigKey.PubKey.SerializeCompressed()
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remoteKey := lc.remoteChanCfg.MultiSigKey.PubKey.SerializeCompressed()
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multiSigScript, err := input.GenMultiSigScript(localKey, remoteKey)
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if err != nil {
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return err
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}
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fundingPkScript, err := input.WitnessScriptHash(multiSigScript)
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if err != nil {
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return err
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}
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lc.signDesc = &input.SignDescriptor{
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KeyDesc: lc.localChanCfg.MultiSigKey,
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WitnessScript: multiSigScript,
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Output: &wire.TxOut{
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PkScript: fundingPkScript,
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Value: int64(lc.channelState.Capacity),
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},
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HashType: txscript.SigHashAll,
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InputIndex: 0,
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}
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return nil
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}
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// getSignedCommitTx function take the latest commitment transaction and
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// populate it with witness data.
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func (lc *LightningChannel) getSignedCommitTx() (*wire.MsgTx, error) {
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// Fetch the current commitment transaction, along with their signature
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// for the transaction.
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localCommit := lc.channelState.LocalCommitment
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commitTx := localCommit.CommitTx.Copy()
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theirSig := append(localCommit.CommitSig, byte(txscript.SigHashAll))
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// With this, we then generate the full witness so the caller can
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// broadcast a fully signed transaction.
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lc.signDesc.SigHashes = txscript.NewTxSigHashes(commitTx)
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ourSigRaw, err := lc.txSigner.SignOutputRaw(commitTx, lc.signDesc)
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if err != nil {
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return nil, err
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}
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ourSig := append(ourSigRaw, byte(txscript.SigHashAll))
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// With the final signature generated, create the witness stack
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// required to spend from the multi-sig output.
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ourKey := lc.localChanCfg.MultiSigKey.PubKey.SerializeCompressed()
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theirKey := lc.remoteChanCfg.MultiSigKey.PubKey.SerializeCompressed()
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commitTx.TxIn[0].Witness = input.SpendMultiSig(
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lc.signDesc.WitnessScript, ourKey,
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ourSig, theirKey, theirSig,
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)
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return commitTx, nil
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}
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