contractcourt/chainwatcher: remove close observer for loop
This commit removes the for loop in the closeObserver, as it wasn't serving any purpose. After receiving a spend notification we would return, breaking out of the loop. When getting a quit signal we would also return, making the loop only do one iteration in any case.
This commit is contained in:
Johan T. Halseth
parent
097fd50747
commit
7e397067f6
@ -295,136 +295,134 @@ func (c *chainWatcher) closeObserver(spendNtfn *chainntnfs.SpendEvent) {
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log.Infof("Close observer for ChannelPoint(%v) active",
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c.chanState.FundingOutpoint)
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for {
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select {
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// We've detected a spend of the channel onchain! Depending on
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// the type of spend, we'll act accordingly , so we'll examine
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// the spending transaction to determine what we should do.
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//
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// TODO(Roasbeef): need to be able to ensure this only triggers
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// on confirmation, to ensure if multiple txns are broadcast, we
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// act on the one that's timestamped
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case commitSpend, ok := <-spendNtfn.Spend:
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// If the channel was closed, then this means that the
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// notifier exited, so we will as well.
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if !ok {
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return
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}
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// Otherwise, the remote party might have broadcast a
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// prior revoked state...!!!
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commitTxBroadcast := commitSpend.SpendingTx
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localCommit, remoteCommit, err := c.chanState.LatestCommitments()
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if err != nil {
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log.Errorf("Unable to fetch channel state for "+
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"chan_point=%v", c.chanState.FundingOutpoint)
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return
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}
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// We'll not retrieve the latest sate of the revocation
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// store so we can populate the information within the
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// channel state object that we have.
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//
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// TODO(roasbeef): mutation is bad mkay
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_, err = c.chanState.RemoteRevocationStore()
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if err != nil {
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log.Errorf("Unable to fetch revocation state for "+
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"chan_point=%v", c.chanState.FundingOutpoint)
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return
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}
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// If this is our commitment transaction, then we can
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// exit here as we don't have any further processing we
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// need to do (we can't cheat ourselves :p).
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commitmentHash := localCommit.CommitTx.TxHash()
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isOurCommitment := commitSpend.SpenderTxHash.IsEqual(
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&commitmentHash,
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)
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if isOurCommitment {
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if err := c.dispatchLocalForceClose(
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commitSpend, *localCommit,
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); err != nil {
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log.Errorf("unable to handle local"+
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"close for chan_point=%v: %v",
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c.chanState.FundingOutpoint, err)
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}
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return
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}
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// Next, we'll check to see if this is a cooperative
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// channel closure or not. This is characterized by
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// having an input sequence number that's finalized.
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// This won't happen with regular commitment
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// transactions due to the state hint encoding scheme.
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if commitTxBroadcast.TxIn[0].Sequence == wire.MaxTxInSequenceNum {
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err := c.dispatchCooperativeClose(commitSpend)
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if err != nil {
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log.Errorf("unable to handle co op close: %v", err)
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}
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return
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}
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log.Warnf("Unprompted commitment broadcast for "+
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"ChannelPoint(%v) ", c.chanState.FundingOutpoint)
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// Decode the state hint encoded within the commitment
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// transaction to determine if this is a revoked state
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// or not.
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obfuscator := c.stateHintObfuscator
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broadcastStateNum := lnwallet.GetStateNumHint(
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commitTxBroadcast, obfuscator,
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)
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remoteStateNum := remoteCommit.CommitHeight
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switch {
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// If state number spending transaction matches the
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// current latest state, then they've initiated a
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// unilateral close. So we'll trigger the unilateral
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// close signal so subscribers can clean up the state
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// as necessary.
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//
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// We'll also handle the case of the remote party
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// broadcasting their commitment transaction which is
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// one height above ours. This case can arise when we
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// initiate a state transition, but the remote party
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// has a fail crash _after_ accepting the new state,
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// but _before_ sending their signature to us.
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case broadcastStateNum >= remoteStateNum:
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if err := c.dispatchRemoteForceClose(
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commitSpend, *remoteCommit,
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); err != nil {
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log.Errorf("unable to handle remote "+
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"close for chan_point=%v: %v",
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c.chanState.FundingOutpoint, err)
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}
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// If the state number broadcast is lower than the
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// remote node's current un-revoked height, then
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// THEY'RE ATTEMPTING TO VIOLATE THE CONTRACT LAID OUT
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// WITHIN THE PAYMENT CHANNEL. Therefore we close the
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// signal indicating a revoked broadcast to allow
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// subscribers to
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// swiftly dispatch justice!!!
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case broadcastStateNum < remoteStateNum:
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if err := c.dispatchContractBreach(
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commitSpend, remoteCommit,
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broadcastStateNum,
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); err != nil {
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log.Errorf("unable to handle channel "+
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"breach for chan_point=%v: %v",
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c.chanState.FundingOutpoint, err)
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}
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}
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// Now that a spend has been detected, we've done our
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// job, so we'll exit immediately.
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return
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// The chainWatcher has been signalled to exit, so we'll do so now.
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case <-c.quit:
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select {
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// We've detected a spend of the channel onchain! Depending on
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// the type of spend, we'll act accordingly , so we'll examine
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// the spending transaction to determine what we should do.
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//
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// TODO(Roasbeef): need to be able to ensure this only triggers
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// on confirmation, to ensure if multiple txns are broadcast, we
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// act on the one that's timestamped
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case commitSpend, ok := <-spendNtfn.Spend:
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// If the channel was closed, then this means that the
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// notifier exited, so we will as well.
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if !ok {
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return
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}
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// Otherwise, the remote party might have broadcast a
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// prior revoked state...!!!
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commitTxBroadcast := commitSpend.SpendingTx
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localCommit, remoteCommit, err := c.chanState.LatestCommitments()
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if err != nil {
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log.Errorf("Unable to fetch channel state for "+
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"chan_point=%v", c.chanState.FundingOutpoint)
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return
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}
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// We'll not retrieve the latest sate of the revocation
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// store so we can populate the information within the
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// channel state object that we have.
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//
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// TODO(roasbeef): mutation is bad mkay
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_, err = c.chanState.RemoteRevocationStore()
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if err != nil {
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log.Errorf("Unable to fetch revocation state for "+
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"chan_point=%v", c.chanState.FundingOutpoint)
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return
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}
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// If this is our commitment transaction, then we can
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// exit here as we don't have any further processing we
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// need to do (we can't cheat ourselves :p).
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commitmentHash := localCommit.CommitTx.TxHash()
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isOurCommitment := commitSpend.SpenderTxHash.IsEqual(
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&commitmentHash,
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)
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if isOurCommitment {
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if err := c.dispatchLocalForceClose(
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commitSpend, *localCommit,
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); err != nil {
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log.Errorf("unable to handle local"+
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"close for chan_point=%v: %v",
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c.chanState.FundingOutpoint, err)
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}
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return
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}
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// Next, we'll check to see if this is a cooperative
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// channel closure or not. This is characterized by
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// having an input sequence number that's finalized.
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// This won't happen with regular commitment
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// transactions due to the state hint encoding scheme.
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if commitTxBroadcast.TxIn[0].Sequence == wire.MaxTxInSequenceNum {
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err := c.dispatchCooperativeClose(commitSpend)
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if err != nil {
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log.Errorf("unable to handle co op close: %v", err)
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}
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return
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}
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log.Warnf("Unprompted commitment broadcast for "+
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"ChannelPoint(%v) ", c.chanState.FundingOutpoint)
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// Decode the state hint encoded within the commitment
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// transaction to determine if this is a revoked state
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// or not.
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obfuscator := c.stateHintObfuscator
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broadcastStateNum := lnwallet.GetStateNumHint(
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commitTxBroadcast, obfuscator,
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)
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remoteStateNum := remoteCommit.CommitHeight
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switch {
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// If state number spending transaction matches the
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// current latest state, then they've initiated a
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// unilateral close. So we'll trigger the unilateral
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// close signal so subscribers can clean up the state
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// as necessary.
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//
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// We'll also handle the case of the remote party
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// broadcasting their commitment transaction which is
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// one height above ours. This case can arise when we
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// initiate a state transition, but the remote party
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// has a fail crash _after_ accepting the new state,
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// but _before_ sending their signature to us.
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case broadcastStateNum >= remoteStateNum:
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if err := c.dispatchRemoteForceClose(
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commitSpend, *remoteCommit,
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); err != nil {
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log.Errorf("unable to handle remote "+
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"close for chan_point=%v: %v",
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c.chanState.FundingOutpoint, err)
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}
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// If the state number broadcast is lower than the
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// remote node's current un-revoked height, then
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// THEY'RE ATTEMPTING TO VIOLATE THE CONTRACT LAID OUT
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// WITHIN THE PAYMENT CHANNEL. Therefore we close the
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// signal indicating a revoked broadcast to allow
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// subscribers to
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// swiftly dispatch justice!!!
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case broadcastStateNum < remoteStateNum:
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if err := c.dispatchContractBreach(
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commitSpend, remoteCommit,
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broadcastStateNum,
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); err != nil {
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log.Errorf("unable to handle channel "+
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"breach for chan_point=%v: %v",
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c.chanState.FundingOutpoint, err)
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}
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}
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// Now that a spend has been detected, we've done our
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// job, so we'll exit immediately.
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return
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// The chainWatcher has been signalled to exit, so we'll do so now.
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case <-c.quit:
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return
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}
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}
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