mirror of https://github.com/guggero/chantools
Begin implementing rescuefunding command
Oliver Gugger
4 years ago
parent
4c92de59e5
commit
338c22fc2e
@ -0,0 +1,145 @@
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package main
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import (
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"bytes"
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"fmt"
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"github.com/btcsuite/btcutil/hdkeychain"
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"github.com/guggero/chantools/lnd"
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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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const (
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MaxChannelLookup = 5000
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)
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type rescueFundingCommand struct {
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RootKey string `long:"rootkey" description:"BIP32 HD root (m/) key to derive the key for our node from."`
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OtherNodePub string `long:"othernodepub" description:"The extended public key (xpub) of the other node's multisig branch (m/1017'/<coin_type>'/0'/0)."`
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FundingAddr string `long:"fundingaddr" description:"The bech32 script address of the funding output where the coins to be spent are locked in."`
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FundingOutpoint string `long:"fundingoutpoint" description:"The funding transaction outpoint (<txid>:<txindex>)."`
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FundingAmount int64 `long:"fundingamount" description:"The exact amount in satoshis that is locked in the funding output."`
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SweepAddr string `long:"sweepaddr" description:"The address to sweep the rescued funds to."`
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SatPerByte int64 `long:"satperbyte" description:"The fee rate to use in satoshis/vByte."`
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}
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func (c *rescueFundingCommand) Execute(_ []string) error {
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setupChainParams(cfg)
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var (
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extendedKey *hdkeychain.ExtendedKey
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otherPub *hdkeychain.ExtendedKey
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err error
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)
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// Check that root key is valid or fall back to console input.
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switch {
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case c.RootKey != "":
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extendedKey, err = hdkeychain.NewKeyFromString(c.RootKey)
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default:
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extendedKey, _, err = rootKeyFromConsole()
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}
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if err != nil {
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return fmt.Errorf("error reading root key: %v", err)
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}
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// Read other node's xpub.
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otherPub, err = hdkeychain.NewKeyFromString(c.OtherNodePub)
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if err != nil {
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return fmt.Errorf("error parsing other node's xpub: %v", err)
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}
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// Decode target funding address.
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hash, isScript, err := lnd.DecodeAddressHash(c.FundingAddr, chainParams)
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if err != nil {
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return fmt.Errorf("error decoding funding address: %v", err)
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}
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if !isScript {
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return fmt.Errorf("funding address must be a P2WSH address")
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}
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return rescueFunding(extendedKey, otherPub, hash)
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}
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func rescueFunding(localNodeKey *hdkeychain.ExtendedKey,
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otherNodekey *hdkeychain.ExtendedKey, scriptHash []byte) error {
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// First, we need to derive the correct branch from the local root key.
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localMultisig, err := lnd.DeriveChildren(localNodeKey, []uint32{
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lnd.HardenedKeyStart + uint32(keychain.BIP0043Purpose),
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lnd.HardenedKeyStart + chainParams.HDCoinType,
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lnd.HardenedKeyStart + uint32(keychain.KeyFamilyMultiSig),
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0,
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})
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if err != nil {
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return fmt.Errorf("could not derive local multisig key: %v",
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err)
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}
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log.Infof("Looking for matching multisig keys, this will take a while")
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localIndex, otherIndex, script, err := findMatchingIndices(
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localMultisig, otherNodekey, scriptHash,
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)
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if err != nil {
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return fmt.Errorf("could not derive keys: %v", err)
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}
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log.Infof("Found local key with index %d and other key with index %d "+
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"for witness script %x", localIndex, otherIndex, script)
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// TODO(guggero):
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// * craft PSBT with input, sweep output and partial signature
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// * do fee estimation based on full amount
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// * create `signpsbt` command for the other node operator
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return nil
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}
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func findMatchingIndices(localNodeKey *hdkeychain.ExtendedKey,
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otherNodekey *hdkeychain.ExtendedKey, scriptHash []byte) (uint32,
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uint32, []byte, error) {
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// Loop through both the local and the remote indices of the branches up
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// to MaxChannelLookup.
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for local := uint32(0); local < MaxChannelLookup; local++ {
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for other := uint32(0); other < MaxChannelLookup; other++ {
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localKey, err := localNodeKey.Child(local)
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if err != nil {
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return 0, 0, nil, fmt.Errorf("error "+
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"deriving local key: %v", err)
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}
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localPub, err := localKey.ECPubKey()
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if err != nil {
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return 0, 0, nil, fmt.Errorf("error "+
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"deriving local pubkey: %v", err)
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}
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otherKey, err := otherNodekey.Child(other)
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if err != nil {
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return 0, 0, nil, fmt.Errorf("error "+
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"deriving other key: %v", err)
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}
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otherPub, err := otherKey.ECPubKey()
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if err != nil {
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return 0, 0, nil, fmt.Errorf("error "+
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"deriving other pubkey: %v", err)
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}
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script, out, err := input.GenFundingPkScript(
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localPub.SerializeCompressed(),
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otherPub.SerializeCompressed(), 123,
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)
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if err != nil {
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return 0, 0, nil, fmt.Errorf("error "+
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"generating funding script: %v", err)
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}
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if bytes.Contains(out.PkScript, scriptHash) {
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return local, other, script, nil
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}
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}
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if local > 0 && local%100 == 0 {
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log.Infof("Checked %d of %d local keys", local,
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MaxChannelLookup)
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}
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}
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return 0, 0, nil, fmt.Errorf("no matching pubkeys found")
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}
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