Splice with htlcs (#568)

Add support for splicing with pending HTLCs in the channel state,
using the quiescence protocol.

src/commonMain/kotlin/fr/acinq/lightning/Features.kt

@@ -242,6 +242,13 @@ sealed class Feature {
         override val scopes: Set<FeatureScope> get() = setOf(FeatureScope.Init)
     }
 
+    @Serializable
+    object Quiescence : Feature() {
+        override val rfcName get() = "option_quiescence"
+        override val mandatory get() = 34
+        override val scopes: Set<FeatureScope> get() = setOf(FeatureScope.Init, FeatureScope.Node)
+    }
+
 }
 
 @Serializable
@@ -320,6 +327,7 @@ data class Features(val activated: Map<Feature, FeatureSupport>, val unknown: Se
             Feature.ChannelBackupClient,
             Feature.ChannelBackupProvider,
             Feature.ExperimentalSplice,
+            Feature.Quiescence
         )
 
         operator fun invoke(bytes: ByteVector): Features = invoke(bytes.toByteArray())

src/commonMain/kotlin/fr/acinq/lightning/NodeParams.kt

@@ -203,6 +203,7 @@ data class NodeParams(
             Feature.PayToOpenClient to FeatureSupport.Optional,
             Feature.ChannelBackupClient to FeatureSupport.Optional,
             Feature.ExperimentalSplice to FeatureSupport.Optional,
+            Feature.Quiescence to FeatureSupport.Mandatory
         ),
         dustLimit = 546.sat,
         maxRemoteDustLimit = 600.sat,

src/commonMain/kotlin/fr/acinq/lightning/channel/ChannelAction.kt

@@ -129,5 +129,7 @@ sealed class ChannelAction {
     }
 
     data class EmitEvent(val event: ChannelEvents) : ChannelAction()
+
+    object Disconnect : ChannelAction()
     // @formatter:on
 }

src/commonMain/kotlin/fr/acinq/lightning/channel/ChannelCommand.kt

@@ -62,10 +62,11 @@ sealed class ChannelCommand {
     data class WatchReceived(val watch: WatchEvent) : ChannelCommand()
 
     sealed interface ForbiddenDuringSplice
+    sealed interface ForbiddenDuringQuiescence
     sealed class Htlc : ChannelCommand() {
-        data class Add(val amount: MilliSatoshi, val paymentHash: ByteVector32, val cltvExpiry: CltvExpiry, val onion: OnionRoutingPacket, val paymentId: UUID, val commit: Boolean = false) : Htlc(), ForbiddenDuringSplice
+        data class Add(val amount: MilliSatoshi, val paymentHash: ByteVector32, val cltvExpiry: CltvExpiry, val onion: OnionRoutingPacket, val paymentId: UUID, val commit: Boolean = false) : Htlc(), ForbiddenDuringSplice, ForbiddenDuringQuiescence
 
-        sealed class Settlement : Htlc(), ForbiddenDuringSplice {
+        sealed class Settlement : Htlc(), ForbiddenDuringSplice, ForbiddenDuringQuiescence {
             abstract val id: Long
 
             data class Fulfill(override val id: Long, val r: ByteVector32, val commit: Boolean = false) : Settlement()
@@ -81,8 +82,8 @@ sealed class ChannelCommand {
 
     sealed class Commitment : ChannelCommand() {
         object Sign : Commitment(), ForbiddenDuringSplice
-        data class UpdateFee(val feerate: FeeratePerKw, val commit: Boolean = false) : Commitment(), ForbiddenDuringSplice
-        data object CheckHtlcTimeout : Commitment()
+        data class UpdateFee(val feerate: FeeratePerKw, val commit: Boolean = false) : Commitment(), ForbiddenDuringSplice, ForbiddenDuringQuiescence
+        object CheckHtlcTimeout : Commitment()
         sealed class Splice : Commitment() {
             data class Request(val replyTo: CompletableDeferred<Response>, val spliceIn: SpliceIn?, val spliceOut: SpliceOut?, val requestRemoteFunding: LiquidityAds.RequestRemoteFunding?, val feerate: FeeratePerKw, val origins: List<Origin.PayToOpenOrigin> = emptyList()) : Splice() {
                 val pushAmount: MilliSatoshi = spliceIn?.pushAmount ?: 0.msat
@@ -116,7 +117,8 @@ sealed class ChannelCommand {
                     data object InsufficientFunds : Failure()
                     data object InvalidSpliceOutPubKeyScript : Failure()
                     data object SpliceAlreadyInProgress : Failure()
-                    data object ChannelNotIdle : Failure()
+                    data object ConcurrentRemoteSplice : Failure()
+                    data object ChannelNotQuiescent : Failure()
                     data class InvalidLiquidityAds(val reason: ChannelException) : Failure()
                     data class FundingFailure(val reason: FundingContributionFailure) : Failure()
                     data object CannotStartSession : Failure()
@@ -130,7 +132,7 @@ sealed class ChannelCommand {
     }
 
     sealed class Close : ChannelCommand() {
-        data class MutualClose(val scriptPubKey: ByteVector?, val feerates: ClosingFeerates?) : Close()
+        data class MutualClose(val scriptPubKey: ByteVector?, val feerates: ClosingFeerates?) : Close(), ForbiddenDuringSplice, ForbiddenDuringQuiescence
         data object ForceClose : Close()
     }
 

src/commonMain/kotlin/fr/acinq/lightning/channel/ChannelException.kt

@@ -45,7 +45,7 @@ data class InvalidRbfNonInitiator                  (override val channelId: Byte
 data class InvalidRbfAttempt                       (override val channelId: ByteVector32) : ChannelException(channelId, "invalid rbf attempt")
 data class InvalidSpliceAlreadyInProgress          (override val channelId: ByteVector32) : ChannelException(channelId, "invalid splice attempt: the current splice attempt must be completed or aborted first")
 data class InvalidSpliceAbortNotAcked              (override val channelId: ByteVector32) : ChannelException(channelId, "invalid splice attempt: our previous tx_abort has not been acked")
-data class InvalidSpliceChannelNotIdle             (override val channelId: ByteVector32) : ChannelException(channelId, "invalid splice attempt: channel is not idle")
+data class InvalidSpliceNotQuiescent               (override val channelId: ByteVector32) : ChannelException(channelId, "invalid splice attempt: the channel is not quiescent")
 data class NoMoreHtlcsClosingInProgress            (override val channelId: ByteVector32) : ChannelException(channelId, "cannot send new htlcs, closing in progress")
 data class ClosingAlreadyInProgress                (override val channelId: ByteVector32) : ChannelException(channelId, "closing already in progress")
 data class CannotCloseWithUnsignedOutgoingHtlcs    (override val channelId: ByteVector32) : ChannelException(channelId, "cannot close when there are unsigned outgoing htlc")
@@ -89,4 +89,5 @@ data class InvalidFailureCode                      (override val channelId: Byte
 data class PleasePublishYourCommitment             (override val channelId: ByteVector32) : ChannelException(channelId, "please publish your local commitment")
 data class CommandUnavailableInThisState           (override val channelId: ByteVector32, val state: String) : ChannelException(channelId, "cannot execute command in state=$state")
 data class ForbiddenDuringSplice                   (override val channelId: ByteVector32, val command: String?) : ChannelException(channelId, "cannot process $command while splicing")
+data class InvalidSpliceRequest                    (override val channelId: ByteVector32) : ChannelException(channelId, "invalid splice request")
 // @formatter:on