Update protocol for continuous inbound liquidity

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

@@ -126,6 +126,13 @@ sealed class Feature {
         override val scopes: Set<FeatureScope> get() = setOf(FeatureScope.Init, FeatureScope.Node)
     }
 
+    @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
     object ChannelType : Feature() {
         override val rfcName get() = "option_channel_type"
@@ -185,15 +192,15 @@ sealed class Feature {
         override val scopes: Set<FeatureScope> get() = setOf(FeatureScope.Init, FeatureScope.Node)
     }
 
-    /** This feature bit should be activated when a node accepts on-the-fly channel creation. */
+    /** DEPRECATED: this feature bit was used for the legacy pay-to-open protocol. */
     @Serializable
     object PayToOpenClient : Feature() {
         override val rfcName get() = "pay_to_open_client"
         override val mandatory get() = 136
         override val scopes: Set<FeatureScope> get() = setOf(FeatureScope.Init)
     }
 
-    /** This feature bit should be activated when a node supports opening channels on-the-fly when liquidity is missing to receive a payment. */
+    /** DEPRECATED: this feature bit was used for the legacy pay-to-open protocol. */
     @Serializable
     object PayToOpenProvider : Feature() {
         override val rfcName get() = "pay_to_open_provider"
@@ -249,13 +256,30 @@ sealed class Feature {
         override val scopes: Set<FeatureScope> get() = setOf(FeatureScope.Init)
     }
 
+    /** This feature bit should be activated when a node accepts on-the-fly funding using the [MaybeAddHtlc] message. */
     @Serializable
-    object Quiescence : Feature() {
-        override val rfcName get() = "option_quiescence"
-        override val mandatory get() = 34
+    object OnTheFlyFundingClient : Feature() {
+        override val rfcName get() = "on_the_fly_funding_client"
+        override val mandatory get() = 156
+        override val scopes: Set<FeatureScope> get() = setOf(FeatureScope.Init)
+    }
+
+    /** This feature bit should be activated when a node supports on-the-fly funding when liquidity is missing to receive a payment. */
+    @Serializable
+    object OnTheFlyFundingProvider : Feature() {
+        override val rfcName get() = "on_the_fly_funding_provider"
+        override val mandatory get() = 158
         override val scopes: Set<FeatureScope> get() = setOf(FeatureScope.Init, FeatureScope.Node)
     }
 
+    /** This feature bit should be activated when a node accepts exchanging payment preimages for a fee credit using the [AddFeeCredit] message. */
+    @Serializable
+    object OnTheFlyFundingFeeCredit : Feature() {
+        override val rfcName: String = "on_the_fly_fee_credit"
+        override val mandatory get() = 160
+        override val scopes: Set<FeatureScope> get() = setOf(FeatureScope.Init)
+    }
+
 }
 
 @Serializable
@@ -321,6 +345,7 @@ data class Features(val activated: Map<Feature, FeatureSupport>, val unknown: Se
             Feature.AnchorOutputs,
             Feature.ShutdownAnySegwit,
             Feature.DualFunding,
+            Feature.Quiescence,
             Feature.ChannelType,
             Feature.PaymentMetadata,
             Feature.TrampolinePayment,
@@ -336,7 +361,9 @@ data class Features(val activated: Map<Feature, FeatureSupport>, val unknown: Se
             Feature.ChannelBackupClient,
             Feature.ChannelBackupProvider,
             Feature.ExperimentalSplice,
-            Feature.Quiescence
+            Feature.OnTheFlyFundingClient,
+            Feature.OnTheFlyFundingProvider,
+            Feature.OnTheFlyFundingFeeCredit,
         )
 
         operator fun invoke(bytes: ByteVector): Features = invoke(bytes.toByteArray())

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

@@ -1,23 +1,27 @@
 package fr.acinq.lightning
 
 import fr.acinq.bitcoin.ByteVector32
+import fr.acinq.bitcoin.OutPoint
 import fr.acinq.bitcoin.Satoshi
+import fr.acinq.lightning.blockchain.electrum.WalletState
 import fr.acinq.lightning.channel.InteractiveTxParams
 import fr.acinq.lightning.channel.SharedFundingInput
+import fr.acinq.lightning.channel.TransactionFees
 import fr.acinq.lightning.channel.states.ChannelStateWithCommitments
 import fr.acinq.lightning.channel.states.Normal
 import fr.acinq.lightning.channel.states.WaitForFundingCreated
 import fr.acinq.lightning.db.IncomingPayment
 import fr.acinq.lightning.utils.sum
-import fr.acinq.lightning.wire.Node
-import fr.acinq.lightning.wire.PleaseOpenChannel
-import kotlinx.coroutines.CompletableDeferred
 
 sealed interface NodeEvents
 
 sealed interface SwapInEvents : NodeEvents {
-    data class Requested(val req: PleaseOpenChannel) : SwapInEvents
-    data class Accepted(val requestId: ByteVector32, val serviceFee: MilliSatoshi, val miningFee: Satoshi) : SwapInEvents
+    data class Requested(val walletInputs: List<WalletState.Utxo>) : SwapInEvents {
+        val totalAmount: Satoshi = walletInputs.map { it.amount }.sum()
+    }
+    data class Accepted(val inputs: Set<OutPoint>, val amount: Satoshi, val fees: TransactionFees) : SwapInEvents {
+        val receivedAmount: Satoshi = amount - fees.serviceFee - fees.miningFee
+    }
 }
 
 sealed interface ChannelEvents : NodeEvents {
@@ -27,6 +31,7 @@ sealed interface ChannelEvents : NodeEvents {
 }
 
 sealed interface LiquidityEvents : NodeEvents {
+    /** Amount of the liquidity event, before fees are paid. */
     val amount: MilliSatoshi
     val fee: MilliSatoshi
     val source: Source
@@ -39,11 +44,12 @@ sealed interface LiquidityEvents : NodeEvents {
                 data class OverAbsoluteFee(val maxAbsoluteFee: Satoshi) : TooExpensive()
                 data class OverRelativeFee(val maxRelativeFeeBasisPoints: Int) : TooExpensive()
             }
-            data object ChannelInitializing : Reason()
+            data object ChannelFundingInProgress : Reason()
+            data class MissingOffChainAmountTooLow(val missingOffChainAmount: MilliSatoshi) : Reason()
+            data class ChannelFundingCancelled(val paymentHash: ByteVector32) : Reason()
         }
     }
-
-    data class ApprovalRequested(override val amount: MilliSatoshi, override val fee: MilliSatoshi, override val source: Source, val replyTo: CompletableDeferred<Boolean>) : LiquidityEvents
+    data class Accepted(override val amount: MilliSatoshi, override val fee: MilliSatoshi, override val source: Source) : LiquidityEvents
 }
 
 /** This is useful on iOS to ask the OS for time to finish some sensitive tasks. */
@@ -56,7 +62,6 @@ sealed interface SensitiveTaskEvents : NodeEvents {
     }
     data class TaskStarted(val id: TaskIdentifier) : SensitiveTaskEvents
     data class TaskEnded(val id: TaskIdentifier) : SensitiveTaskEvents
-
 }
 
 /** This will be emitted in a corner case where the user restores a wallet on an older version of the app, which is unable to read the channel data. */

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

@@ -182,16 +182,16 @@ data class NodeParams(
             Feature.StaticRemoteKey to FeatureSupport.Mandatory,
             Feature.AnchorOutputs to FeatureSupport.Optional, // can't set Mandatory because peers prefers AnchorOutputsZeroFeeHtlcTx
             Feature.DualFunding to FeatureSupport.Mandatory,
+            Feature.Quiescence to FeatureSupport.Mandatory,
             Feature.ShutdownAnySegwit to FeatureSupport.Mandatory,
             Feature.ChannelType to FeatureSupport.Mandatory,
             Feature.PaymentMetadata to FeatureSupport.Optional,
             Feature.ExperimentalTrampolinePayment to FeatureSupport.Optional,
             Feature.ZeroReserveChannels to FeatureSupport.Optional,
             Feature.WakeUpNotificationClient to FeatureSupport.Optional,
-            Feature.PayToOpenClient to FeatureSupport.Optional,
             Feature.ChannelBackupClient to FeatureSupport.Optional,
             Feature.ExperimentalSplice to FeatureSupport.Optional,
-            Feature.Quiescence to FeatureSupport.Mandatory
+            Feature.OnTheFlyFundingClient to FeatureSupport.Optional,
         ),
         dustLimit = 546.sat,
         maxRemoteDustLimit = 600.sat,
@@ -219,6 +219,6 @@ data class NodeParams(
         maxPaymentAttempts = 5,
         zeroConfPeers = emptySet(),
         paymentRecipientExpiryParams = RecipientCltvExpiryParams(CltvExpiryDelta(75), CltvExpiryDelta(200)),
-        liquidityPolicy = MutableStateFlow<LiquidityPolicy>(LiquidityPolicy.Auto(maxAbsoluteFee = 2_000.sat, maxRelativeFeeBasisPoints = 3_000 /* 3000 = 30 % */, skipAbsoluteFeeCheck = false))
+        liquidityPolicy = MutableStateFlow<LiquidityPolicy>(LiquidityPolicy.Auto(inboundLiquidityTarget = null, maxAbsoluteFee = 2_000.sat, maxRelativeFeeBasisPoints = 3_000 /* 3000 = 30 % */, skipAbsoluteFeeCheck = false))
     )
 }

src/commonMain/kotlin/fr/acinq/lightning/blockchain/electrum/SwapInManager.kt

@@ -2,21 +2,18 @@ package fr.acinq.lightning.blockchain.electrum
 
 import fr.acinq.bitcoin.OutPoint
 import fr.acinq.bitcoin.Transaction
-import fr.acinq.bitcoin.TxId
-import fr.acinq.lightning.Lightning
 import fr.acinq.lightning.SwapInParams
 import fr.acinq.lightning.channel.FundingContributions.Companion.stripInputWitnesses
 import fr.acinq.lightning.channel.LocalFundingStatus
 import fr.acinq.lightning.channel.RbfStatus
-import fr.acinq.lightning.channel.SignedSharedTransaction
 import fr.acinq.lightning.channel.SpliceStatus
 import fr.acinq.lightning.channel.states.*
-import fr.acinq.lightning.io.RequestChannelOpen
+import fr.acinq.lightning.io.OpenOrSpliceChannel
 import fr.acinq.lightning.logging.MDCLogger
 import fr.acinq.lightning.utils.sat
 
 internal sealed class SwapInCommand {
-    data class TrySwapIn(val currentBlockHeight: Int, val wallet: WalletState, val swapInParams: SwapInParams, val trustedTxs: Set<TxId>) : SwapInCommand()
+    data class TrySwapIn(val currentBlockHeight: Int, val wallet: WalletState, val swapInParams: SwapInParams) : SwapInCommand()
     data class UnlockWalletInputs(val inputs: Set<OutPoint>) : SwapInCommand()
 }
 
@@ -33,19 +30,15 @@ internal sealed class SwapInCommand {
 class SwapInManager(private var reservedUtxos: Set<OutPoint>, private val logger: MDCLogger) {
     constructor(bootChannels: List<PersistedChannelState>, logger: MDCLogger) : this(reservedWalletInputs(bootChannels), logger)
 
-    internal fun process(cmd: SwapInCommand): RequestChannelOpen? = when (cmd) {
+    internal fun process(cmd: SwapInCommand): OpenOrSpliceChannel? = when (cmd) {
         is SwapInCommand.TrySwapIn -> {
             val availableWallet = cmd.wallet.withoutReservedUtxos(reservedUtxos).withConfirmations(cmd.currentBlockHeight, cmd.swapInParams)
             logger.info { "swap-in wallet balance: deeplyConfirmed=${availableWallet.deeplyConfirmed.balance}, weaklyConfirmed=${availableWallet.weaklyConfirmed.balance}, unconfirmed=${availableWallet.unconfirmed.balance}" }
-            val utxos = buildSet {
-                // some utxos may be used for swap-in even if they are not confirmed, for example when migrating from the legacy phoenix android app
-                addAll(availableWallet.all.filter { cmd.trustedTxs.contains(it.outPoint.txid) })
-                addAll(availableWallet.deeplyConfirmed.filter { Transaction.write(it.previousTx.stripInputWitnesses()).size < 65_000 })
-            }.toList()
+            val utxos = availableWallet.deeplyConfirmed.filter { Transaction.write(it.previousTx.stripInputWitnesses()).size < 65_000 }
             if (utxos.balance > 0.sat) {
                 logger.info { "swap-in wallet: requesting channel using ${utxos.size} utxos with balance=${utxos.balance}" }
                 reservedUtxos = reservedUtxos.union(utxos.map { it.outPoint })
-                RequestChannelOpen(Lightning.randomBytes32(), utxos)
+                OpenOrSpliceChannel(utxos)
             } else {
                 null
             }

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

@@ -1,9 +1,9 @@
 package fr.acinq.lightning.channel
 
 import fr.acinq.bitcoin.*
-import fr.acinq.lightning.ChannelEvents
 import fr.acinq.lightning.CltvExpiry
 import fr.acinq.lightning.MilliSatoshi
+import fr.acinq.lightning.NodeEvents
 import fr.acinq.lightning.blockchain.Watch
 import fr.acinq.lightning.channel.states.PersistedChannelState
 import fr.acinq.lightning.db.ChannelClosingType
@@ -78,8 +78,14 @@ sealed class ChannelAction {
             abstract val origin: Origin?
             abstract val txId: TxId
             abstract val localInputs: Set<OutPoint>
+            /** @param amount amount received after deducing service and mining fees. */
             data class ViaNewChannel(val amount: MilliSatoshi, val serviceFee: MilliSatoshi, val miningFee: Satoshi, override val localInputs: Set<OutPoint>, override val txId: TxId, override val origin: Origin?) : StoreIncomingPayment()
-            data class ViaSpliceIn(val amount: MilliSatoshi, val serviceFee: MilliSatoshi, val miningFee: Satoshi, override val localInputs: Set<OutPoint>, override val txId: TxId, override val origin: Origin.PayToOpenOrigin?) : StoreIncomingPayment()
+            /** @param amount amount received after deducing service and mining fees. */
+            data class ViaSpliceIn(val amount: MilliSatoshi, val serviceFee: MilliSatoshi, val miningFee: Satoshi, override val localInputs: Set<OutPoint>, override val txId: TxId, override val origin: Origin?) : StoreIncomingPayment()
+            data class Cancelled(override val origin: Origin.OffChainPayment) : StoreIncomingPayment() {
+                override val localInputs: Set<OutPoint> = setOf()
+                override val txId: TxId = TxId(ByteVector32.Zeroes)
+            }
         }
         /** Payment sent through on-chain operations (channel close or splice-out) */
         sealed class StoreOutgoingPayment : Storage() {
@@ -128,8 +134,8 @@ sealed class ChannelAction {
         }
     }
 
-    data class EmitEvent(val event: ChannelEvents) : ChannelAction()
+    data class EmitEvent(val event: NodeEvents) : ChannelAction()
 
-    object Disconnect : ChannelAction()
+    data object Disconnect : ChannelAction()
     // @formatter:on
 }

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

@@ -32,10 +32,11 @@ sealed class ChannelCommand {
             val fundingTxFeerate: FeeratePerKw,
             val localParams: LocalParams,
             val remoteInit: InitMessage,
-            val channelFlags: Byte,
+            val channelFlags: ChannelFlags,
             val channelConfig: ChannelConfig,
             val channelType: ChannelType.SupportedChannelType,
-            val channelOrigin: Origin? = null
+            val requestRemoteFunding: LiquidityAds.RequestRemoteFunding?,
+            val channelOrigin: Origin?,
         ) : Init() {
             fun temporaryChannelId(keyManager: KeyManager): ByteVector32 = keyManager.channelKeys(localParams.fundingKeyPath).temporaryChannelId
         }
@@ -47,7 +48,8 @@ sealed class ChannelCommand {
             val walletInputs: List<WalletState.Utxo>,
             val localParams: LocalParams,
             val channelConfig: ChannelConfig,
-            val remoteInit: InitMessage
+            val remoteInit: InitMessage,
+            val leaseRate: LiquidityAds.LeaseRate?,
         ) : Init()
 
         data class Restore(val state: PersistedChannelState) : Init()
@@ -83,22 +85,16 @@ sealed class ChannelCommand {
     sealed class Commitment : ChannelCommand() {
         object Sign : Commitment(), ForbiddenDuringSplice
         data class UpdateFee(val feerate: FeeratePerKw, val commit: Boolean = false) : Commitment(), ForbiddenDuringSplice, ForbiddenDuringQuiescence
-        object CheckHtlcTimeout : Commitment()
+        data 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() {
+            data class Request(val replyTo: CompletableDeferred<Response>, val spliceIn: SpliceIn?, val spliceOut: SpliceOut?, val requestRemoteFunding: LiquidityAds.RequestRemoteFunding?, val feerate: FeeratePerKw, val origins: List<Origin>) : Splice() {
                 val pushAmount: MilliSatoshi = spliceIn?.pushAmount ?: 0.msat
                 val spliceOutputs: List<TxOut> = spliceOut?.let { listOf(TxOut(it.amount, it.scriptPubKey)) } ?: emptyList()
 
                 data class SpliceIn(val walletInputs: List<WalletState.Utxo>, val pushAmount: MilliSatoshi = 0.msat)
                 data class SpliceOut(val amount: Satoshi, val scriptPubKey: ByteVector)
             }
 
-            /**
-             * @param miningFee on-chain fee that will be paid for the splice transaction.
-             * @param serviceFee service-fee that will be paid to the remote node for a service they provide with the splice transaction.
-             */
-            data class Fees(val miningFee: Satoshi, val serviceFee: MilliSatoshi)
-
             sealed class Response {
                 /**
                  * This response doesn't fully guarantee that the splice will confirm, because our peer may potentially double-spend