Merge pull request #5274 from halseth/anchors-reserved-value-max

[anchors] cap value reserved for anchor fee bumping

lncfg/protocol.go

@@ -1,3 +1,5 @@
+// +build !rpctest
+
 package lncfg
 
 // ProtocolOptions is a struct that we use to be able to test backwards
@@ -18,8 +20,9 @@ type ProtocolOptions struct {
 	// mini.
 	WumboChans bool `long:"wumbo-channels" description:"if set, then lnd will create and accept requests for channels larger chan 0.16 BTC"`
 
-	// Anchors enables anchor commitments.
-	Anchors bool `long:"anchors" description:"enable support for anchor commitments"`
+	// NoAnchors should be set if we don't want to support opening or accepting
+	// channels having the anchor commitment type.
+	NoAnchors bool `long:"no-anchors" description:"disable support for anchor commitments"`
 }
 
 // Wumbo returns true if lnd should permit the creation and acceptance of wumbo
@@ -31,5 +34,5 @@ func (l *ProtocolOptions) Wumbo() bool {
 // NoAnchorCommitments returns true if we have disabled support for the anchor
 // commitment type.
 func (l *ProtocolOptions) NoAnchorCommitments() bool {
-	return !l.Anchors
+	return l.NoAnchors
 }

lncfg/protocol_rpctest.go

@@ -0,0 +1,38 @@
+// +build rpctest
+
+package lncfg
+
+// ProtocolOptions is a struct that we use to be able to test backwards
+// compatibility of protocol additions, while defaulting to the latest within
+// lnd, or to enable experimental protocol changes.
+type ProtocolOptions struct {
+	// LegacyProtocol is a sub-config that houses all the legacy protocol
+	// options.  These are mostly used for integration tests as most modern
+	// nodes shuld always run with them on by default.
+	LegacyProtocol `group:"legacy" namespace:"legacy"`
+
+	// ExperimentalProtocol is a sub-config that houses any experimental
+	// protocol features that also require a build-tag to activate.
+	ExperimentalProtocol
+
+	// WumboChans should be set if we want to enable support for wumbo
+	// (channels larger than 0.16 BTC) channels, which is the opposite of
+	// mini.
+	WumboChans bool `long:"wumbo-channels" description:"if set, then lnd will create and accept requests for channels larger chan 0.16 BTC"`
+
+	// Anchors enables anchor commitments.
+	// TODO(halseth): transition itests to anchors instead!
+	Anchors bool `long:"anchors" description:"enable support for anchor commitments"`
+}
+
+// Wumbo returns true if lnd should permit the creation and acceptance of wumbo
+// channels.
+func (l *ProtocolOptions) Wumbo() bool {
+	return l.WumboChans
+}
+
+// NoAnchorCommitments returns true if we have disabled support for the anchor
+// commitment type.
+func (l *ProtocolOptions) NoAnchorCommitments() bool {
+	return !l.Anchors
+}

lnwallet/wallet.go

@@ -39,6 +39,13 @@ const (
 	// TODO(halseth): update constant to target a specific commit size at
 	// set fee rate.
 	anchorChanReservedValue = btcutil.Amount(10_000)
+
+	// maxAnchorChanReservedValue is the maximum value we'll reserve for
+	// anchor channel fee bumping. We cap it at 10 times the per-channel
+	// amount such that nodes with a high number of channels don't have to
+	// keep around a very large amount for the unlikely scenario that they
+	// all close at the same time.
+	maxAnchorChanReservedValue = 10 * anchorChanReservedValue
 )
 
 var (
@@ -597,9 +604,11 @@ func (l *LightningWallet) PsbtFundingVerify(pendingChanID [32]byte,
 	// If this commit type is an anchor channel we add that to our counter,
 	// but only if we are contributing funds to the channel. This is done
 	// to still allow incoming channels even though we have no UTXOs
-	// available, as in bootstrapping phases.
+	// available, as in bootstrapping phases. We only count public
+	// channels.
+	isPublic := pendingReservation.partialState.ChannelFlags&lnwire.FFAnnounceChannel != 0
 	if pendingReservation.partialState.ChanType.HasAnchors() &&
-		intent.LocalFundingAmt() > 0 {
+		intent.LocalFundingAmt() > 0 && isPublic {
 		numAnchors++
 	}
 
@@ -812,9 +821,11 @@ func (l *LightningWallet) handleFundingReserveRequest(req *InitFundingReserveMsg
 	// If this commit type is an anchor channel we add that to our counter,
 	// but only if we are contributing funds to the channel. This is done
 	// to still allow incoming channels even though we have no UTXOs
-	// available, as in bootstrapping phases.
+	// available, as in bootstrapping phases. We only count public
+	// channels.
+	isPublic := req.Flags&lnwire.FFAnnounceChannel != 0
 	if req.CommitType == CommitmentTypeAnchorsZeroFeeHtlcTx &&
-		fundingIntent.LocalFundingAmt() > 0 {
+		fundingIntent.LocalFundingAmt() > 0 && isPublic {
 		numAnchors++
 	}
 
@@ -881,8 +892,8 @@ func (l *LightningWallet) handleFundingReserveRequest(req *InitFundingReserveMsg
 	req.err <- nil
 }
 
-// currentNumAnchorChans returns the current number of anchor channels the
-// wallet should be ready to fee bump if needed.
+// currentNumAnchorChans returns the current number of non-private anchor
+// channels the wallet should be ready to fee bump if needed.
 func (l *LightningWallet) currentNumAnchorChans() (int, error) {
 	// Count all anchor channels that are open or pending
 	// open, or waiting close.
@@ -892,10 +903,22 @@ func (l *LightningWallet) currentNumAnchorChans() (int, error) {
 	}
 
 	var numAnchors int
-	for _, c := range chans {
+	cntChannel := func(c *channeldb.OpenChannel) {
+		// We skip private channels, as we assume they won't be used
+		// for routing.
+		if c.ChannelFlags&lnwire.FFAnnounceChannel == 0 {
+			return
+		}
+
+		// Count anchor channels.
 		if c.ChanType.HasAnchors() {
 			numAnchors++
 		}
+
+	}
+
+	for _, c := range chans {
+		cntChannel(c)
 	}
 
 	// We also count pending close channels.
@@ -918,9 +941,7 @@ func (l *LightningWallet) currentNumAnchorChans() (int, error) {
 			continue
 		}
 
-		if c.ChanType.HasAnchors() {
-			numAnchors++
-		}
+		cntChannel(c)
 	}
 
 	return numAnchors, nil
@@ -1000,6 +1021,9 @@ func (l *LightningWallet) CheckReservedValue(in []wire.OutPoint,
 
 	// We reserve a given amount for each anchor channel.
 	reserved := btcutil.Amount(numAnchorChans) * anchorChanReservedValue
+	if reserved > maxAnchorChanReservedValue {
+		reserved = maxAnchorChanReservedValue
+	}
 
 	if walletBalance < reserved {
 		walletLog.Debugf("Reserved value=%v above final "+