Add maxExcess_opt to ChannelParams in NodeParams

This will be used by non-initiators when funding dual funded channels and splicing
ACINQ · Sep 4, 2024 · 8cc2e4a · 8cc2e4a
1 parent 4a03134
commit 8cc2e4a
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Showing 4 changed files with 14 additions and 4 deletions.
diff --git a/eclair-core/src/main/resources/reference.conf b/eclair-core/src/main/resources/reference.conf
@@ -197,6 +197,10 @@ eclair {
 
       min-time-between-updates = 1 hour // minimum time between channel updates because the balance changed
     }
+
+    // if > 0, excess channel funding up to this amount will be added to the amount contributed when funding
+    // dual-funded channels or splices. This is useful to avoid paying fees to add a small change output.
+    max-excess = 0
   }
 
   balance-check-interval = 1 hour

diff --git a/eclair-core/src/main/scala/fr/acinq/eclair/NodeParams.scala b/eclair-core/src/main/scala/fr/acinq/eclair/NodeParams.scala
@@ -476,6 +476,8 @@ object NodeParams extends Logging {
     val maxNoChannels = config.getInt("peer-connection.max-no-channels")
     require(maxNoChannels > 0, "peer-connection.max-no-channels must be > 0")
 
+    val maxExcess_opt = if (config.getInt("channel.max-excess") > 0) Some(Satoshi(config.getInt("channel.max-excess"))) else None
+
     NodeParams(
       nodeKeyManager = nodeKeyManager,
       channelKeyManager = channelKeyManager,
@@ -524,7 +526,8 @@ object NodeParams extends Logging {
         quiescenceTimeout = FiniteDuration(config.getDuration("channel.quiescence-timeout").getSeconds, TimeUnit.SECONDS),
         balanceThresholds = config.getConfigList("channel.channel-update.balance-thresholds").asScala.map(conf => BalanceThreshold(Satoshi(conf.getLong("available-sat")), Satoshi(conf.getLong("max-htlc-sat")))).toSeq,
         minTimeBetweenUpdates = FiniteDuration(config.getDuration("channel.channel-update.min-time-between-updates").getSeconds, TimeUnit.SECONDS),
-        acceptIncomingStaticRemoteKeyChannels = config.getBoolean("channel.accept-incoming-static-remote-key-channels")
+        acceptIncomingStaticRemoteKeyChannels = config.getBoolean("channel.accept-incoming-static-remote-key-channels"),
+        maxExcess_opt = maxExcess_opt,
       ),
       onChainFeeConf = OnChainFeeConf(
         feeTargets = feeTargets,

diff --git a/eclair-core/src/main/scala/fr/acinq/eclair/channel/fsm/Channel.scala b/eclair-core/src/main/scala/fr/acinq/eclair/channel/fsm/Channel.scala
@@ -104,7 +104,8 @@ object Channel {
                          quiescenceTimeout: FiniteDuration,
                          balanceThresholds: Seq[BalanceThreshold],
                          minTimeBetweenUpdates: FiniteDuration,
-                         acceptIncomingStaticRemoteKeyChannels: Boolean) {
+                         acceptIncomingStaticRemoteKeyChannels: Boolean,
+                         maxExcess_opt: Option[Satoshi]) {
     require(0 <= maxHtlcValueInFlightPercent && maxHtlcValueInFlightPercent <= 100, "max-htlc-value-in-flight-percent must be between 0 and 100")
     require(balanceThresholds.sortBy(_.available) == balanceThresholds, "channel-update.balance-thresholds must be sorted by available-sat")
 

diff --git a/eclair-core/src/test/scala/fr/acinq/eclair/TestConstants.scala b/eclair-core/src/test/scala/fr/acinq/eclair/TestConstants.scala
@@ -144,7 +144,8 @@ object TestConstants {
         quiescenceTimeout = 2 minutes,
         balanceThresholds = Nil,
         minTimeBetweenUpdates = 0 hours,
-        acceptIncomingStaticRemoteKeyChannels = false
+        acceptIncomingStaticRemoteKeyChannels = false,
+        maxExcess_opt = None
       ),
       onChainFeeConf = OnChainFeeConf(
         feeTargets = FeeTargets(funding = ConfirmationPriority.Medium, closing = ConfirmationPriority.Medium),
@@ -316,7 +317,8 @@ object TestConstants {
         quiescenceTimeout = 2 minutes,
         balanceThresholds = Nil,
         minTimeBetweenUpdates = 0 hour,
-        acceptIncomingStaticRemoteKeyChannels = false
+        acceptIncomingStaticRemoteKeyChannels = false,
+        maxExcess_opt = None
       ),
       onChainFeeConf = OnChainFeeConf(
         feeTargets = FeeTargets(funding = ConfirmationPriority.Medium, closing = ConfirmationPriority.Medium),