lnwallet: introduce distinct HTLC counter+index on top of updateLog
In this commit, we fix an existing derivation from the commitment state machine as defined within the specification. Before this commit, we only kept a single counter which both HTLC adds and fails/settles would share. This was valid in the prior pre-spec iteration of the state machine. However in the current draft of the spec, only a distinct counter for HTLCs are used throughout. This would cause an incompatibility, as if we mixed adds and settles during an exchange, then our counter values would differ with other implementations. To remedy this, we now introduce a distinct HTLC counter and index within the updateLog. Each Add will increment both the log counter, and the HTLC counter. Each Settle/Fail will only increment the log counter. Inbound Settle/Fails will index into the HTLC index as to target the proper HTLC. The PaymentDescriptor type has been extended with an additional field (HltcIndex) which itself tracks the index of an incoming/outgoing HTLC.
This commit is contained in:
Olaoluwa Osuntokun
parent
da9a771a58
commit
3b94e5df4d
@ -152,13 +152,23 @@ type PaymentDescriptor struct {
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// Amount is the HTLC amount in milli-satoshis.
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Amount lnwire.MilliSatoshi
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// Index is the log entry number that his HTLC update has within the
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// LogIndex is the log entry number that his HTLC update has within the
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// log. Depending on if IsIncoming is true, this is either an entry the
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// remote party added, or one that we added locally.
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Index uint64
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LogIndex uint64
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// HtlcIndex is the index within the main update log for this HTLC.
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// Entires within the log of type Add will have this field populated,
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// as other entries will point to the entry via this counter.
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//
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// NOTE: This field will only be populate if EntryType is Add.
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HtlcIndex uint64
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// ParentIndex is the index of the log entry that this HTLC update
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// settles or times out.
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//
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// NOTE: This field will only be populate if EntryType is Fail or
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// Settle.
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ParentIndex uint64
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// localOutputIndex is the output index of this HTLc output in the
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@ -593,6 +603,8 @@ func (s *commitmentChain) tail() *commitment {
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// changes are stored before they're committed to the chain. Once an entry has
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// been committed in both the local and remote commitment chain, then it can be
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// removed from this log.
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// TODO(roasbeef): update with offer vs update distinction
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//
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// TODO(roasbeef): create lightning package, move commitment and update to
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// package?
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@ -604,6 +616,12 @@ type updateLog struct {
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// commitment states, we include all updates up to this index.
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logIndex uint64
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// htlcCounter is a monotonically increasing integer that tracks the
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// total number of offered HTLC's by the owner of this update log. We
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// use a distinct index for this purpose, as update's that remove
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// entires from the log will be indexed using this counter.
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htlcCounter uint64
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// ackIndex is a special "pointer" index into the log that tracks the
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// position which, up to, all changes have been ACK'd by the remote
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// party. When receiving new commitment states, we include all of our
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@ -626,6 +644,10 @@ type updateLog struct {
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// updateIndex is an index that maps a particular entries index to the
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// list element within the list.List above.
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updateIndex map[uint64]*list.Element
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// offerIndex is an index that maps the counter for offered HTLC's to
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// their list elemtn within the main list.List.
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htlcIndex map[uint64]*list.Element
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}
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// newUpdateLog creates a new updateLog instance.
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@ -633,6 +655,7 @@ func newUpdateLog() *updateLog {
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return &updateLog{
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List: list.New(),
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updateIndex: make(map[uint64]*list.Element),
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htlcIndex: make(map[uint64]*list.Element),
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}
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}
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@ -643,20 +666,43 @@ func (u *updateLog) appendUpdate(pd *PaymentDescriptor) {
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u.logIndex++
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}
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// lookup attempts to look up an update entry according to it's index value. In
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// the case that the entry isn't found, a nil pointer is returned.
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func (u *updateLog) lookup(i uint64) *PaymentDescriptor {
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return u.updateIndex[i].Value.(*PaymentDescriptor)
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// appendHtlc appends a new HTLC offer to the tip of the update log. The entry
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// is also added to the offer index accordingly.
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func (u *updateLog) appendHtlc(pd *PaymentDescriptor) {
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u.htlcIndex[u.htlcCounter] = u.PushBack(pd)
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u.htlcCounter++
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u.logIndex++
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}
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// lookupHtlc attempts to look up an offered HTLC according to it's offer
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// index. If the entry isn't found, then a nil pointer is returned.
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func (u *updateLog) lookupHtlc(i uint64) *PaymentDescriptor {
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htlc, ok := u.htlcIndex[i]
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if !ok {
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return nil
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}
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return htlc.Value.(*PaymentDescriptor)
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}
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// remove attempts to remove an entry from the update log. If the entry is
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// found, then the entry will be removed from the update log and index.
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func (u *updateLog) remove(i uint64) {
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func (u *updateLog) removeUpdate(i uint64) {
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entry := u.updateIndex[i]
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u.Remove(entry)
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delete(u.updateIndex, i)
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}
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// removeHtlc attempts to remove an HTLC offer form the update log. If the
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// entry is found, then the entry will be removed from both the main log and
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// the offer index.
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func (u *updateLog) removeHtlc(i uint64) {
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entry := u.htlcIndex[i]
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u.Remove(entry)
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delete(u.htlcIndex, i)
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}
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// initiateTransition marks that the caller has extended the commitment chain
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// of the remote party with the contents of the updateLog. This function will
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// mark the log index value at this point so it can later be marked as ACK'd.
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@ -702,8 +748,8 @@ func compactLogs(ourLog, theirLog *updateLog,
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if remoteChainTail >= htlc.removeCommitHeightRemote &&
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localChainTail >= htlc.removeCommitHeightLocal {
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logA.remove(htlc.Index)
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logB.remove(htlc.ParentIndex)
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logA.removeUpdate(htlc.LogIndex)
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logB.removeHtlc(htlc.ParentIndex)
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}
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}
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@ -1674,13 +1720,13 @@ func (lc *LightningChannel) restoreStateLogs() error {
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}
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if !htlc.Incoming {
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pd.Index = ourCounter
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lc.localUpdateLog.appendUpdate(pd)
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pd.HtlcIndex = ourCounter
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lc.localUpdateLog.appendHtlc(pd)
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ourCounter++
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} else {
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pd.Index = theirCounter
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lc.remoteUpdateLog.appendUpdate(pd)
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pd.HtlcIndex = theirCounter
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lc.remoteUpdateLog.appendHtlc(pd)
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lc.rHashMap[pd.RHash] = append(lc.rHashMap[pd.RHash], pd)
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theirCounter++
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@ -1713,7 +1759,7 @@ func (lc *LightningChannel) fetchHTLCView(theirLogIndex, ourLogIndex uint64) *ht
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// This HTLC is active from this point-of-view iff the log
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// index of the state update is below the specified index in
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// our update log.
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if htlc.Index < ourLogIndex {
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if htlc.LogIndex < ourLogIndex {
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ourHTLCs = append(ourHTLCs, htlc)
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}
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}
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@ -1725,7 +1771,7 @@ func (lc *LightningChannel) fetchHTLCView(theirLogIndex, ourLogIndex uint64) *ht
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// If this is an incoming HTLC, then it is only active from
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// this point-of-view if the index of the HTLC addition in
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// their log is below the specified view index.
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if htlc.Index < theirLogIndex {
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if htlc.LogIndex < theirLogIndex {
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theirHTLCs = append(theirHTLCs, htlc)
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}
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}
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@ -2005,9 +2051,9 @@ func (lc *LightningChannel) evaluateHTLCView(view *htlcView, ourBalance,
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lc.channelState.TotalMSatReceived += entry.Amount
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}
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addEntry := lc.remoteUpdateLog.lookup(entry.ParentIndex)
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addEntry := lc.remoteUpdateLog.lookupHtlc(entry.ParentIndex)
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skipThem[addEntry.Index] = struct{}{}
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skipThem[addEntry.HtlcIndex] = struct{}{}
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processRemoveEntry(entry, ourBalance, theirBalance,
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nextHeight, remoteChain, true)
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}
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@ -2025,9 +2071,9 @@ func (lc *LightningChannel) evaluateHTLCView(view *htlcView, ourBalance,
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lc.channelState.TotalMSatSent += entry.Amount
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}
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addEntry := lc.localUpdateLog.lookup(entry.ParentIndex)
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addEntry := lc.localUpdateLog.lookupHtlc(entry.ParentIndex)
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skipUs[addEntry.Index] = struct{}{}
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skipUs[addEntry.HtlcIndex] = struct{}{}
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processRemoveEntry(entry, ourBalance, theirBalance,
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nextHeight, remoteChain, false)
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}
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@ -2037,7 +2083,7 @@ func (lc *LightningChannel) evaluateHTLCView(view *htlcView, ourBalance,
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// added HTLCs.
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for _, entry := range view.ourUpdates {
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isAdd := entry.EntryType == Add
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if _, ok := skipUs[entry.Index]; !isAdd || ok {
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if _, ok := skipUs[entry.HtlcIndex]; !isAdd || ok {
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continue
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}
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@ -2047,7 +2093,7 @@ func (lc *LightningChannel) evaluateHTLCView(view *htlcView, ourBalance,
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}
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for _, entry := range view.theirUpdates {
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isAdd := entry.EntryType == Add
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if _, ok := skipThem[entry.Index]; !isAdd || ok {
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if _, ok := skipThem[entry.HtlcIndex]; !isAdd || ok {
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continue
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}
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@ -3005,12 +3051,13 @@ func (lc *LightningChannel) AddHTLC(htlc *lnwire.UpdateAddHTLC) (uint64, error)
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RHash: PaymentHash(htlc.PaymentHash),
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Timeout: htlc.Expiry,
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Amount: htlc.Amount,
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Index: lc.localUpdateLog.logIndex,
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LogIndex: lc.localUpdateLog.logIndex,
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HtlcIndex: lc.localUpdateLog.htlcCounter,
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}
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lc.localUpdateLog.appendUpdate(pd)
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lc.localUpdateLog.appendHtlc(pd)
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return pd.Index, nil
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return pd.HtlcIndex, nil
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}
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// ReceiveHTLC adds an HTLC to the state machine's remote update log. This
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@ -3030,14 +3077,15 @@ func (lc *LightningChannel) ReceiveHTLC(htlc *lnwire.UpdateAddHTLC) (uint64, err
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RHash: PaymentHash(htlc.PaymentHash),
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Timeout: htlc.Expiry,
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Amount: htlc.Amount,
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Index: lc.remoteUpdateLog.logIndex,
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LogIndex: lc.remoteUpdateLog.logIndex,
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HtlcIndex: lc.remoteUpdateLog.htlcCounter,
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}
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lc.remoteUpdateLog.appendUpdate(pd)
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lc.remoteUpdateLog.appendHtlc(pd)
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lc.rHashMap[pd.RHash] = append(lc.rHashMap[pd.RHash], pd)
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return pd.Index, nil
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return pd.HtlcIndex, nil
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}
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// SettleHTLC attempts to settle an existing outstanding received HTLC. The
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@ -3061,8 +3109,8 @@ func (lc *LightningChannel) SettleHTLC(preimage [32]byte) (uint64,
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pd := &PaymentDescriptor{
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Amount: targetHTLC.Amount,
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RPreimage: preimage,
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Index: lc.localUpdateLog.logIndex,
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ParentIndex: targetHTLC.Index,
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LogIndex: lc.localUpdateLog.logIndex,
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ParentIndex: targetHTLC.HtlcIndex,
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EntryType: Settle,
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}
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@ -3075,19 +3123,19 @@ func (lc *LightningChannel) SettleHTLC(preimage [32]byte) (uint64,
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}
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lc.availableLocalBalance += pd.Amount
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return targetHTLC.Index, targetHTLC.Amount, nil
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return targetHTLC.HtlcIndex, targetHTLC.Amount, nil
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}
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// ReceiveHTLCSettle attempts to settle an existing outgoing HTLC indexed by an
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// index into the local log. If the specified index doesn't exist within the
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// log, and error is returned. Similarly if the preimage is invalid w.r.t to
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// the referenced of then a distinct error is returned.
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func (lc *LightningChannel) ReceiveHTLCSettle(preimage [32]byte, logIndex uint64) error {
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func (lc *LightningChannel) ReceiveHTLCSettle(preimage [32]byte, htlcIndex uint64) error {
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lc.Lock()
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defer lc.Unlock()
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paymentHash := sha256.Sum256(preimage[:])
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htlc := lc.localUpdateLog.lookup(logIndex)
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htlc := lc.localUpdateLog.lookupHtlc(htlcIndex)
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if htlc == nil {
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return fmt.Errorf("non existant log entry")
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}
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@ -3100,9 +3148,9 @@ func (lc *LightningChannel) ReceiveHTLCSettle(preimage [32]byte, logIndex uint64
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pd := &PaymentDescriptor{
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Amount: htlc.Amount,
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RPreimage: preimage,
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ParentIndex: htlc.Index,
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ParentIndex: htlc.HtlcIndex,
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RHash: htlc.RHash,
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Index: lc.remoteUpdateLog.logIndex,
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LogIndex: lc.remoteUpdateLog.logIndex,
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EntryType: Settle,
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}
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@ -3129,8 +3177,8 @@ func (lc *LightningChannel) FailHTLC(rHash [32]byte) (uint64, error) {
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pd := &PaymentDescriptor{
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Amount: addEntry.Amount,
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RHash: addEntry.RHash,
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ParentIndex: addEntry.Index,
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Index: lc.localUpdateLog.logIndex,
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ParentIndex: addEntry.HtlcIndex,
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LogIndex: lc.localUpdateLog.logIndex,
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EntryType: Fail,
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}
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@ -3142,19 +3190,19 @@ func (lc *LightningChannel) FailHTLC(rHash [32]byte) (uint64, error) {
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delete(lc.rHashMap, rHash)
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}
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return addEntry.Index, nil
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return addEntry.HtlcIndex, nil
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}
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// ReceiveFailHTLC attempts to cancel a targeted HTLC by its log index,
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// ReceiveFailHTLC attempts to cancel a targeted HTLC by its log htlc,
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// inserting an entry which will remove the target log entry within the next
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// commitment update. This method should be called in response to the upstream
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// party cancelling an outgoing HTLC. The value of the failed HTLC is returned
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// along with an error indicating success.
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func (lc *LightningChannel) ReceiveFailHTLC(logIndex uint64) (lnwire.MilliSatoshi, error) {
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func (lc *LightningChannel) ReceiveFailHTLC(htlcIndex uint64) (lnwire.MilliSatoshi, error) {
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lc.Lock()
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defer lc.Unlock()
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htlc := lc.localUpdateLog.lookup(logIndex)
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htlc := lc.localUpdateLog.lookupHtlc(htlcIndex)
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if htlc == nil {
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return 0, fmt.Errorf("unable to find HTLC to fail")
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}
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@ -3162,8 +3210,8 @@ func (lc *LightningChannel) ReceiveFailHTLC(logIndex uint64) (lnwire.MilliSatosh
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pd := &PaymentDescriptor{
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Amount: htlc.Amount,
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RHash: htlc.RHash,
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ParentIndex: htlc.Index,
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Index: lc.remoteUpdateLog.logIndex,
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ParentIndex: htlc.HtlcIndex,
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LogIndex: lc.remoteUpdateLog.logIndex,
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EntryType: Fail,
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}
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@ -1505,7 +1505,7 @@ func TestStateUpdatePersistence(t *testing.T) {
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// Newly generated pkScripts for HTLCs should be the same as in the old channel.
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for _, entry := range aliceChannel.localUpdateLog.updateIndex {
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htlc := entry.Value.(*PaymentDescriptor)
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restoredHtlc := aliceChannelNew.localUpdateLog.lookup(htlc.Index)
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restoredHtlc := aliceChannelNew.localUpdateLog.lookupHtlc(htlc.HtlcIndex)
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if !bytes.Equal(htlc.ourPkScript, restoredHtlc.ourPkScript) {
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t.Fatalf("alice ourPkScript in ourLog: expected %X, got %X",
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htlc.ourPkScript[:5], restoredHtlc.ourPkScript[:5])
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@ -1517,7 +1517,7 @@ func TestStateUpdatePersistence(t *testing.T) {
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}
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for _, entry := range aliceChannel.remoteUpdateLog.updateIndex {
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htlc := entry.Value.(*PaymentDescriptor)
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restoredHtlc := aliceChannelNew.remoteUpdateLog.lookup(htlc.Index)
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restoredHtlc := aliceChannelNew.remoteUpdateLog.lookupHtlc(htlc.HtlcIndex)
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if !bytes.Equal(htlc.ourPkScript, restoredHtlc.ourPkScript) {
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t.Fatalf("alice ourPkScript in theirLog: expected %X, got %X",
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htlc.ourPkScript[:5], restoredHtlc.ourPkScript[:5])
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@ -1529,7 +1529,7 @@ func TestStateUpdatePersistence(t *testing.T) {
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}
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for _, entry := range bobChannel.localUpdateLog.updateIndex {
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htlc := entry.Value.(*PaymentDescriptor)
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restoredHtlc := bobChannelNew.localUpdateLog.lookup(htlc.Index)
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restoredHtlc := bobChannelNew.localUpdateLog.lookupHtlc(htlc.HtlcIndex)
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if !bytes.Equal(htlc.ourPkScript, restoredHtlc.ourPkScript) {
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t.Fatalf("bob ourPkScript in ourLog: expected %X, got %X",
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htlc.ourPkScript[:5], restoredHtlc.ourPkScript[:5])
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@ -1541,7 +1541,7 @@ func TestStateUpdatePersistence(t *testing.T) {
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}
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for _, entry := range bobChannel.remoteUpdateLog.updateIndex {
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htlc := entry.Value.(*PaymentDescriptor)
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restoredHtlc := bobChannelNew.remoteUpdateLog.lookup(htlc.Index)
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restoredHtlc := bobChannelNew.remoteUpdateLog.lookupHtlc(htlc.HtlcIndex)
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if !bytes.Equal(htlc.ourPkScript, restoredHtlc.ourPkScript) {
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t.Fatalf("bob ourPkScript in theirLog: expected %X, got %X",
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htlc.ourPkScript[:5], restoredHtlc.ourPkScript[:5])
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