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lnwallet/channel: add fee updates to update logs

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Instead of special casing the UpdateFee messages, we instead add them to
the update logs like any other HTLC update message. This lets us avoid
having to keep an extra set of variables to keep track of the fee
updates, and instead reuse the commit/ack logic used for other updates.

This fixes a bug where we would reset the pendingFeeUpdate variable
after signing our next commitment, which would make us calculate the new
fee incorrectly if the remote sent a commitment concurrently.

When restoring state logs, we also make sure to re-add any fee updates.
This commit is contained in:
Johan T. Halseth 2019-01-10 12:23:57 +01:00
parent 810c56cdb9
commit 6ffd354d63
No known key found for this signature in database
GPG Key ID: 15BAADA29DA20D26
1 changed files with 22 additions and 103 deletions
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125
lnwallet/channel.go
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@ -1346,17 +1346,6 @@ type LightningChannel struct {
localUpdateLog *updateLog
remoteUpdateLog *updateLog
// pendingFeeUpdate is set to the fee-per-kw we last sent (if we are
// channel initiator) or received (if non-initiator) in an update fee
// message, which haven't yet been included in a commitment. It will
// be nil if no fee update is un-committed.
pendingFeeUpdate *SatPerKWeight
// pendingAckFeeUpdate is set to the last committed fee update which is
// not yet ACKed. This value will be nil if a fee update hasn't been
// initiated.
pendingAckFeeUpdate *SatPerKWeight
// LocalFundingKey is the public key under control by the wallet that
// was used for the 2-of-2 funding output which created this channel.
LocalFundingKey *btcec.PublicKey
@ -1806,15 +1795,6 @@ func (lc *LightningChannel) restoreStateLogs(
// If we did have a dangling commit, then we'll examine which updates
// we included in that state and re-insert them into our update log.
for _, logUpdate := range pendingRemoteCommitDiff.LogUpdates {
// If the log update is a fee update, then it doesn't need an
// entry within the updateLog, so we'll just apply it and move
// on.
if feeUpdate, ok := logUpdate.UpdateMsg.(*lnwire.UpdateFee); ok {
newFeeRate := SatPerKWeight(feeUpdate.FeePerKw)
lc.pendingAckFeeUpdate = &newFeeRate
continue
}
payDesc, err := lc.logUpdateToPayDesc(
&logUpdate, lc.remoteUpdateLog, pendingHeight,
SatPerKWeight(pendingCommit.FeePerKw), pendingRemoteKeys,
@ -1824,7 +1804,8 @@ func (lc *LightningChannel) restoreStateLogs(
return err
}
if payDesc.EntryType == Add {
switch payDesc.EntryType {
case Add:
// The HtlcIndex of the added HTLC _must_ be equal to
// the log's htlcCounter at this point. If it is not we
// panic to catch this.
@ -1837,7 +1818,11 @@ func (lc *LightningChannel) restoreStateLogs(
}
lc.localUpdateLog.appendHtlc(payDesc)
} else {
case FeeUpdate:
lc.localUpdateLog.appendUpdate(payDesc)
default:
lc.localUpdateLog.appendUpdate(payDesc)
lc.remoteUpdateLog.markHtlcModified(payDesc.ParentIndex)
@ -2881,21 +2866,8 @@ func (lc *LightningChannel) createCommitDiff(
// out.
chanID := lnwire.NewChanIDFromOutPoint(&lc.channelState.FundingOutpoint)
// If we have a fee update that we're waiting on an ACK of, then we'll
// create an entry so this is properly retransmitted. Note that we can
// only send an UpdateFee message if we're the initiator of the
// channel.
var logUpdates []channeldb.LogUpdate
if lc.channelState.IsInitiator && lc.pendingFeeUpdate != nil {
logUpdates = append(logUpdates, channeldb.LogUpdate{
UpdateMsg: &lnwire.UpdateFee{
ChanID: chanID,
FeePerKw: uint32(*lc.pendingFeeUpdate),
},
})
}
var (
logUpdates []channeldb.LogUpdate
ackAddRefs []channeldb.AddRef
settleFailRefs []channeldb.SettleFailRef
openCircuitKeys []channeldb.CircuitKey
@ -3172,16 +3144,6 @@ func (lc *LightningChannel) SignNextCommitment() (lnwire.Sig, []lnwire.Sig, erro
// latest commitment update.
lc.remoteCommitChain.addCommitment(newCommitView)
// If we are the channel initiator then we would have signed any sent
// fee update at this point, so mark this update as pending ACK, and
// set pendingFeeUpdate to nil. We can do this since we know we won't
// sign any new commitment before receiving a RevokeAndAck, because of
// the revocation window of 1.
if lc.channelState.IsInitiator {
lc.pendingAckFeeUpdate = lc.pendingFeeUpdate
lc.pendingFeeUpdate = nil
}
return sig, htlcSigs, nil
}
@ -3624,36 +3586,6 @@ func (lc *LightningChannel) computeView(view *htlcView, remoteChain bool,
&theirBalance, nextHeight, remoteChain, updateState)
feePerKw := filteredHTLCView.feePerKw
// Check if any fee updates have taken place since that last
// commitment.
if lc.channelState.IsInitiator {
switch {
// We've sent an update_fee message since our last commitment,
// and now are now creating a commitment that reflects the new
// fee update.
case remoteChain && lc.pendingFeeUpdate != nil:
feePerKw = *lc.pendingFeeUpdate
// We've created a new commitment for the remote chain that
// includes a fee update, and have not received a commitment
// after the fee update has been ACKed.
case !remoteChain && lc.pendingAckFeeUpdate != nil:
feePerKw = *lc.pendingAckFeeUpdate
}
} else {
switch {
// We've received a fee update since the last local commitment,
// so we'll include the fee update in the current view.
case !remoteChain && lc.pendingFeeUpdate != nil:
feePerKw = *lc.pendingFeeUpdate
// Earlier we received a commitment that signed an earlier fee
// update, and now we must ACK that update.
case remoteChain && lc.pendingAckFeeUpdate != nil:
feePerKw = *lc.pendingAckFeeUpdate
}
}
// Now go through all HTLCs at this stage, to calculate the total
// weight, needed to calculate the transaction fee.
var totalHtlcWeight int64
@ -4190,16 +4122,6 @@ func (lc *LightningChannel) ReceiveNewCommitment(commitSig lnwire.Sig,
localCommitmentView.sig = commitSig.ToSignatureBytes()
lc.localCommitChain.addCommitment(localCommitmentView)
// If we are not channel initiator, then the commitment just received
// would've signed any received fee update since last commitment. Mark
// any such fee update as pending ACK (so we remember to ACK it on our
// next commitment), and set pendingFeeUpdate to nil. We can do this
// since we won't receive any new commitment before ACKing.
if !lc.channelState.IsInitiator {
lc.pendingAckFeeUpdate = lc.pendingFeeUpdate
lc.pendingFeeUpdate = nil
}
return nil
}
@ -4220,21 +4142,7 @@ func (lc *LightningChannel) FullySynced() bool {
remoteUpdatesSynced := (lastLocalCommit.theirMessageIndex ==
lastRemoteCommit.theirMessageIndex)
pendingFeeAck := false
// If we have received a fee update which we haven't yet ACKed, then
// we owe a commitment.
if !lc.channelState.IsInitiator {
pendingFeeAck = lc.pendingAckFeeUpdate != nil
}
// If we have sent a fee update which we haven't yet signed, then
// we owe a commitment.
if lc.channelState.IsInitiator {
pendingFeeAck = lc.pendingFeeUpdate != nil
}
return localUpdatesSynced && remoteUpdatesSynced && !pendingFeeAck
return localUpdatesSynced && remoteUpdatesSynced
}
// RevokeCurrentCommitment revokes the next lowest unrevoked commitment
@ -6078,7 +5986,13 @@ func (lc *LightningChannel) UpdateFee(feePerKw SatPerKWeight) error {
return err
}
lc.pendingFeeUpdate = &feePerKw
pd := &PaymentDescriptor{
LogIndex: lc.localUpdateLog.logIndex,
Amount: lnwire.NewMSatFromSatoshis(btcutil.Amount(feePerKw)),
EntryType: FeeUpdate,
}
lc.localUpdateLog.appendUpdate(pd)
return nil
}
@ -6096,8 +6010,13 @@ func (lc *LightningChannel) ReceiveUpdateFee(feePerKw SatPerKWeight) error {
}
// TODO(roasbeef): or just modify to use the other balance?
pd := &PaymentDescriptor{
LogIndex: lc.remoteUpdateLog.logIndex,
Amount: lnwire.NewMSatFromSatoshis(btcutil.Amount(feePerKw)),
EntryType: FeeUpdate,
}
lc.pendingFeeUpdate = &feePerKw
lc.remoteUpdateLog.appendUpdate(pd)
return nil
}