multi: introduce config-level DustThreshold for defining threshold

config.go

@@ -355,6 +355,8 @@ type Config struct {
 
 	GcCanceledInvoicesOnTheFly bool `long:"gc-canceled-invoices-on-the-fly" description:"If true, we'll delete newly canceled invoices on the fly."`
 
+	DustThreshold uint64 `long:"dust-threshold" description:"Sets the dust sum threshold in satoshis for a channel after which dust HTLC's will be failed."`
+
 	Invoices *lncfg.Invoices `group:"invoices" namespace:"invoices"`
 
 	Routing *lncfg.Routing `group:"routing" namespace:"routing"`
@@ -550,6 +552,7 @@ func DefaultConfig() Config {
 		MaxOutgoingCltvExpiry:   htlcswitch.DefaultMaxOutgoingCltvExpiry,
 		MaxChannelFeeAllocation: htlcswitch.DefaultMaxLinkFeeAllocation,
 		MaxCommitFeeRateAnchors: lnwallet.DefaultAnchorsCommitMaxFeeRateSatPerVByte,
+		DustThreshold:           uint64(htlcswitch.DefaultDustThreshold.ToSatoshis()),
 		LogWriter:               build.NewRotatingLogWriter(),
 		DB:                      lncfg.DefaultDB(),
 		Cluster:                 lncfg.DefaultCluster(),