akovalenko/lnd.xprv
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

lnwallet/channel: filter commitment outputs if dust

Browse Source
This commit is contained in:
Conner Fromknecht 2017-09-19 12:45:51 -07:00
parent 4c19320ea0
commit 223f77d135
No known key found for this signature in database
GPG Key ID: 39DE78FBE6ACB0EF
1 changed files with 61 additions and 33 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

94
lnwallet/channel.go
View File

@ -1063,7 +1063,9 @@ type BreachRetribution struct {
// LocalOutputSignDesc is a SignDescriptor which is capable of
// generating the signature necessary to sweep the output within the
// BreachTransaction that pays directly us.
LocalOutputSignDesc SignDescriptor
// NOTE: A nil value indicates that the local output is considered dust
// according to the remote party's dust limit.
LocalOutputSignDesc *SignDescriptor
// LocalOutpoint is the outpoint of the output paying to us (the local
// party) within the breach transaction.
@ -1073,7 +1075,9 @@ type BreachRetribution struct {
// generating the signature required to claim the funds as described
// within the revocation clause of the remote party's commitment
// output.
RemoteOutputSignDesc SignDescriptor
// NOTE: A nil value indicates that the local output is considered dust
// according to the remote party's dust limit.
RemoteOutputSignDesc *SignDescriptor
// RemoteOutpoint is the output of the output paying to the remote
// party within the breach transaction.
@ -1165,6 +1169,53 @@ func newBreachRetribution(chanState *channeldb.OpenChannel, stateNum uint64,
}
}
// Conditionally instantiate a sign descriptor for each of the
// commitment outputs. If either is considered dust using the remote
// party's dust limit, the respective sign descriptor will be nil.
var (
localSignDesc *SignDescriptor
remoteSignDesc *SignDescriptor
)
// Compute the local and remote balances in satoshis.
localAmt := revokedSnapshot.LocalBalance.ToSatoshis()
remoteAmt := revokedSnapshot.RemoteBalance.ToSatoshis()
// If the local balance exceeds the remote party's dust limit,
// instantiate the local sign descriptor.
if localAmt >= chanState.RemoteChanCfg.DustLimit {
// We'll need to reconstruct the single tweak so we can sweep
// our non-delayed pay-to-self output self.
singleTweak := SingleTweakBytes(commitmentPoint,
chanState.LocalChanCfg.PaymentBasePoint)
localSignDesc = &SignDescriptor{
SingleTweak: singleTweak,
PubKey: chanState.LocalChanCfg.PaymentBasePoint,
WitnessScript: localPkScript,
Output: &wire.TxOut{
PkScript: localWitnessHash,
Value: int64(localAmt),
},
HashType: txscript.SigHashAll,
}
}
// Similarly, if the remote balance exceeds the remote party's dust
// limit, assemble the remote sign descriptor.
if remoteAmt >= chanState.RemoteChanCfg.DustLimit {
remoteSignDesc = &SignDescriptor{
PubKey: chanState.LocalChanCfg.RevocationBasePoint,
DoubleTweak: commitmentSecret,
WitnessScript: remotePkScript,
Output: &wire.TxOut{
PkScript: remoteWitnessHash,
Value: int64(remoteAmt),
},
HashType: txscript.SigHashAll,
}
}
// With the commitment outputs located, we'll now generate all the
// retribution structs for each of the HTLC transactions active on the
// remote commitment transaction.
@ -1216,41 +1267,18 @@ func newBreachRetribution(chanState *channeldb.OpenChannel, stateNum uint64,
}
}
// We'll need to reconstruct the single tweak so we can sweep our
// non-delayed pay-to-self output self.
singleTweak := SingleTweakBytes(commitmentPoint,
chanState.LocalChanCfg.PaymentBasePoint)
// Finally, with all the necessary data constructed, we can create the
// BreachRetribution struct which houses all the data necessary to
// swiftly bring justice to the cheating remote party.
return &BreachRetribution{
BreachTransaction: broadcastCommitment,
RevokedStateNum: stateNum,
PendingHTLCs: revokedSnapshot.Htlcs,
LocalOutpoint: localOutpoint,
LocalOutputSignDesc: SignDescriptor{
SingleTweak: singleTweak,
PubKey: chanState.LocalChanCfg.PaymentBasePoint,
WitnessScript: localPkScript,
Output: &wire.TxOut{
PkScript: localWitnessHash,
Value: int64(revokedSnapshot.LocalBalance.ToSatoshis()),
},
HashType: txscript.SigHashAll,
},
RemoteOutpoint: remoteOutpoint,
RemoteOutputSignDesc: SignDescriptor{
PubKey: chanState.LocalChanCfg.RevocationBasePoint,
DoubleTweak: commitmentSecret,
WitnessScript: remotePkScript,
Output: &wire.TxOut{
PkScript: remoteWitnessHash,
Value: int64(revokedSnapshot.RemoteBalance.ToSatoshis()),
},
HashType: txscript.SigHashAll,
},
HtlcRetributions: htlcRetributions,
BreachTransaction: broadcastCommitment,
RevokedStateNum: stateNum,
PendingHTLCs: revokedSnapshot.Htlcs,
LocalOutpoint: localOutpoint,
LocalOutputSignDesc: localSignDesc,
RemoteOutpoint: remoteOutpoint,
RemoteOutputSignDesc: remoteSignDesc,
HtlcRetributions: htlcRetributions,
}, nil
}