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server+contractcourt: hand-off BreachCloseInfo to channel arbitrator

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This also changes the chain_watcher and breacharbiter handoff. The
new logic ensures that the channel is only marked as pending closed
when the channel arbitrator has persisted the resolutions and commit
set.
This commit is contained in:
eugene
2022-01-13 15:01:13 -05:00
parent b7407882ac
commit ebaffb953a
5 changed files with 289 additions and 89 deletions
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101
contractcourt/chain_watcher.go
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@@ -9,6 +9,7 @@ import (
"github.com/btcsuite/btcd/btcec"
"github.com/btcsuite/btcd/chaincfg"
"github.com/btcsuite/btcd/chaincfg/chainhash"
"github.com/btcsuite/btcd/txscript"
"github.com/btcsuite/btcd/wire"
"github.com/btcsuite/btcutil"
@@ -62,6 +63,24 @@ type BreachResolution struct {
FundingOutPoint wire.OutPoint
}
// BreachCloseInfo wraps the BreachResolution with a CommitSet for the latest,
// non-breached state, with the AnchorResolution for the breached state.
type BreachCloseInfo struct {
*BreachResolution
*lnwallet.AnchorResolution
// CommitHash is the hash of the commitment transaction.
CommitHash chainhash.Hash
// CommitSet is the set of known valid commitments at the time the
// breach occurred on-chain.
CommitSet CommitSet
// CloseSummary gives the recipient of the BreachCloseInfo information
// to mark the channel closed in the database.
CloseSummary channeldb.ChannelCloseSummary
}
// CommitSet is a collection of the set of known valid commitments at a given
// instant. If ConfCommitKey is set, then the commitment identified by the
// HtlcSetKey has hit the chain. This struct will be used to examine all live
@@ -129,7 +148,7 @@ type ChainEventSubscription struct {
// ContractBreach is a channel that will be sent upon if we detect a
// contract breach. The struct sent across the channel contains all the
// material required to bring the cheating channel peer to justice.
ContractBreach chan *lnwallet.BreachRetribution
ContractBreach chan *BreachCloseInfo
// Cancel cancels the subscription to the event stream for a particular
// channel. This method should be called once the caller no longer needs to
@@ -155,13 +174,10 @@ type chainWatcherConfig struct {
signer input.Signer
// contractBreach is a method that will be called by the watcher if it
// detects that a contract breach transaction has been confirmed. A
// callback should be passed that when called will mark the channel
// pending close in the database. It will only return a non-nil error
// when the breachArbiter has preserved the necessary breach info for
// this channel point, and the callback has succeeded, meaning it is
// safe to stop watching the channel.
contractBreach func(*lnwallet.BreachRetribution, func() error) error
// detects that a contract breach transaction has been confirmed. It
// will only return a non-nil error when the breachArbiter has
// preserved the necessary breach info for this channel point.
contractBreach func(*lnwallet.BreachRetribution) error
// isOurAddr is a function that returns true if the passed address is
// known to us.
@@ -316,7 +332,7 @@ func (c *chainWatcher) SubscribeChannelEvents() *ChainEventSubscription {
RemoteUnilateralClosure: make(chan *RemoteUnilateralCloseInfo, 1),
LocalUnilateralClosure: make(chan *LocalUnilateralCloseInfo, 1),
CooperativeClosure: make(chan *CooperativeCloseInfo, 1),
ContractBreach: make(chan *lnwallet.BreachRetribution, 1),
ContractBreach: make(chan *BreachCloseInfo, 1),
Cancel: func() {
c.Lock()
delete(c.clientSubscriptions, clientID)
@@ -790,12 +806,27 @@ func (c *chainWatcher) handleKnownRemoteState(
return false, nil
}
// Create an AnchorResolution for the breached state.
anchorRes, err := lnwallet.NewAnchorResolution(
c.cfg.chanState, commitSpend.SpendingTx,
)
if err != nil {
return false, fmt.Errorf("unable to create anchor "+
"resolution: %v", err)
}
// We'll set the ConfCommitKey here as the remote htlc set. This is
// only used to ensure a nil-pointer-dereference doesn't occur and is
// not used otherwise. The HTLC's may not exist for the
// RemotePendingHtlcSet.
chainSet.commitSet.ConfCommitKey = &RemoteHtlcSet
// THEY'RE ATTEMPTING TO VIOLATE THE CONTRACT LAID OUT WITHIN THE
// PAYMENT CHANNEL. Therefore we close the signal indicating a revoked
// broadcast to allow subscribers to swiftly dispatch justice!!!
err = c.dispatchContractBreach(
commitSpend, &chainSet.remoteCommit,
broadcastStateNum, retribution,
commitSpend, chainSet, broadcastStateNum, retribution,
anchorRes,
)
if err != nil {
return false, fmt.Errorf("unable to handle channel "+
@@ -1088,8 +1119,9 @@ func (c *chainWatcher) dispatchRemoteForceClose(
// materials required to bring the cheater to justice, then notify all
// registered subscribers of this event.
func (c *chainWatcher) dispatchContractBreach(spendEvent *chainntnfs.SpendDetail,
remoteCommit *channeldb.ChannelCommitment, broadcastStateNum uint64,
retribution *lnwallet.BreachRetribution) error {
chainSet *chainSet, broadcastStateNum uint64,
retribution *lnwallet.BreachRetribution,
anchorRes *lnwallet.AnchorResolution) error {
log.Warnf("Remote peer has breached the channel contract for "+
"ChannelPoint(%v). Revoked state #%v was broadcast!!!",
@@ -1130,7 +1162,7 @@ func (c *chainWatcher) dispatchContractBreach(spendEvent *chainntnfs.SpendDetail
return spew.Sdump(retribution)
}))
settledBalance := remoteCommit.LocalBalance.ToSatoshis()
settledBalance := chainSet.remoteCommit.LocalBalance.ToSatoshis()
closeSummary := channeldb.ChannelCloseSummary{
ChanPoint: c.cfg.chanState.FundingOutpoint,
ChainHash: c.cfg.chanState.ChainHash,
@@ -1156,38 +1188,35 @@ func (c *chainWatcher) dispatchContractBreach(spendEvent *chainntnfs.SpendDetail
closeSummary.LastChanSyncMsg = chanSync
}
// We create a function closure that will mark the channel as pending
// close in the database. We pass it to the contracBreach method such
// that it can ensure safe handoff of the breach before we close the
// channel.
markClosed := func() error {
// At this point, we've successfully received an ack for the
// breach close, and we can mark the channel as pending force
// closed.
if err := c.cfg.chanState.CloseChannel(
&closeSummary, channeldb.ChanStatusRemoteCloseInitiator,
); err != nil {
return err
}
log.Infof("Breached channel=%v marked pending-closed",
c.cfg.chanState.FundingOutpoint)
return nil
}
// Hand the retribution info over to the breach arbiter.
if err := c.cfg.contractBreach(retribution, markClosed); err != nil {
// Hand the retribution info over to the breach arbiter. This function
// will wait for a response from the breach arbiter and then proceed to
// send a BreachCloseInfo to the channel arbitrator. The channel arb
// will then mark the channel as closed after resolutions and the
// commit set are logged in the arbitrator log.
if err := c.cfg.contractBreach(retribution); err != nil {
log.Errorf("unable to hand breached contract off to "+
"breachArbiter: %v", err)
return err
}
breachRes := &BreachResolution{
FundingOutPoint: c.cfg.chanState.FundingOutpoint,
}
breachInfo := &BreachCloseInfo{
CommitHash: spendEvent.SpendingTx.TxHash(),
BreachResolution: breachRes,
AnchorResolution: anchorRes,
CommitSet: chainSet.commitSet,
CloseSummary: closeSummary,
}
// With the event processed and channel closed, we'll now notify all
// subscribers of the event.
c.Lock()
for _, sub := range c.clientSubscriptions {
select {
case sub.ContractBreach <- retribution:
case sub.ContractBreach <- breachInfo:
case <-c.quit:
c.Unlock()
return fmt.Errorf("quitting")