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lnwallet: ForceCloseSummary should check if to-local output exists

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If the value of the to-local output is below the dust limit, the
ForceCloseSummary should not include a sign descriptor for this output.

We also find the proper to-self output by looking for the expected public
key script and not assume that no HTLC outputs exist.
This commit is contained in:
Christopher Jämthagen 2017-01-24 10:38:25 +01:00 committed by Olaoluwa Osuntokun
parent 52b56b8cf2
commit a6a503bf28
1 changed files with 37 additions and 28 deletions
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65
lnwallet/channel.go
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@ -2146,28 +2146,12 @@ func (lc *LightningChannel) ForceClose() (*ForceCloseSummary, error) {
return nil, err
}
// Locate the output index of the delayed commitment output back to us.
// We'll return the details of this output to the caller so they can
// sweep it once it's mature.
// TODO(roasbeef): also return HTLC info, assumes only p2wsh is commit
// tx
var delayIndex uint32
var delayScript []byte
for i, txOut := range commitTx.TxOut {
if !txscript.IsPayToWitnessScriptHash(txOut.PkScript) {
continue
}
delayIndex = uint32(i)
delayScript = txOut.PkScript
}
// Re-derive the original pkScript for to-self output within the
// commitment transaction. We'll need this to find the corresponding
// output in the commitment transaction and potentially for creating
// the sign descriptor.
csvTimeout := lc.channelState.LocalCsvDelay
selfKey := lc.channelState.OurCommitKey
// Re-derive the original pkScript for out to-self output within the
// commitment transaction. We'll need this for the created sign
// descriptor.
producer := lc.channelState.RevocationProducer
unusedRevocation, err := producer.AtIndex(lc.currentHeight)
if err != nil {
@ -2179,19 +2163,44 @@ func (lc *LightningChannel) ForceClose() (*ForceCloseSummary, error) {
if err != nil {
return nil, err
}
payToUsScriptHash, err := witnessScriptHash(selfScript)
if err != nil {
return nil, err
}
// Locate the output index of the delayed commitment output back to us.
// We'll return the details of this output to the caller so they can
// sweep it once it's mature.
// TODO(roasbeef): also return HTLC info, assumes only p2wsh is commit
// tx
var delayIndex uint32
var delayScript []byte
var selfSignDesc *SignDescriptor
for i, txOut := range commitTx.TxOut {
if !bytes.Equal(payToUsScriptHash, txOut.PkScript) {
continue
}
delayIndex = uint32(i)
delayScript = txOut.PkScript
break
}
// With the necessary information gathered above, create a new sign
// descriptor which is capable of generating the signature the caller
// needs to sweep this output. The hash cache, and input index are not
// set as the caller will decide these values once sweeping the output.
selfSignDesc := &SignDescriptor{
PubKey: selfKey,
WitnessScript: selfScript,
Output: &wire.TxOut{
PkScript: delayScript,
Value: int64(lc.channelState.OurBalance),
},
HashType: txscript.SigHashAll,
// If the output is non-existant (dust), have the sign descriptor be nil.
if len(delayScript) != 0 {
selfSignDesc = &SignDescriptor{
PubKey: selfKey,
WitnessScript: selfScript,
Output: &wire.TxOut{
PkScript: delayScript,
Value: int64(lc.channelState.OurBalance),
},
HashType: txscript.SigHashAll,
}
}
// Finally, close the channel force close signal which notifies any