On-the-fly channel funding based on splicing and liquidity ads

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"
@@ -250,9 +257,9 @@ sealed class Feature {
     }
 
     @Serializable
-    object Quiescence : Feature() {
-        override val rfcName get() = "option_quiescence"
-        override val mandatory get() = 34
+    object OnTheFlyFunding : Feature() {
+        override val rfcName get() = "on_the_fly_funding"
+        override val mandatory get() = 560
         override val scopes: Set<FeatureScope> get() = setOf(FeatureScope.Init, FeatureScope.Node)
     }
 
@@ -322,6 +329,7 @@ data class Features(val activated: Map<Feature, FeatureSupport>, val unknown: Se
             Feature.RouteBlinding,
             Feature.ShutdownAnySegwit,
             Feature.DualFunding,
+            Feature.Quiescence,
             Feature.ChannelType,
             Feature.PaymentMetadata,
             Feature.TrampolinePayment,
@@ -337,7 +345,7 @@ data class Features(val activated: Map<Feature, FeatureSupport>, val unknown: Se
             Feature.ChannelBackupClient,
             Feature.ChannelBackupProvider,
             Feature.ExperimentalSplice,
-            Feature.Quiescence
+            Feature.OnTheFlyFunding
         )
 
         operator fun invoke(bytes: ByteVector): Features = invoke(bytes.toByteArray())
@@ -369,7 +377,8 @@ data class Features(val activated: Map<Feature, FeatureSupport>, val unknown: Se
             Feature.BasicMultiPartPayment to listOf(Feature.PaymentSecret),
             Feature.AnchorOutputs to listOf(Feature.StaticRemoteKey),
             Feature.TrampolinePayment to listOf(Feature.PaymentSecret),
-            Feature.ExperimentalTrampolinePayment to listOf(Feature.PaymentSecret)
+            Feature.ExperimentalTrampolinePayment to listOf(Feature.PaymentSecret),
+            Feature.OnTheFlyFunding to listOf(Feature.ExperimentalSplice)
         )
 
         class FeatureException(message: String) : IllegalArgumentException(message)

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

@@ -2,7 +2,10 @@ package fr.acinq.lightning
 
 import fr.acinq.bitcoin.ByteVector32
 import fr.acinq.bitcoin.PublicKey
+import fr.acinq.bitcoin.OutPoint
 import fr.acinq.bitcoin.Satoshi
+import fr.acinq.lightning.blockchain.electrum.WalletState
+import fr.acinq.lightning.channel.ChannelManagementFees
 import fr.acinq.lightning.channel.InteractiveTxParams
 import fr.acinq.lightning.channel.SharedFundingInput
 import fr.acinq.lightning.channel.states.ChannelStateWithCommitments
@@ -11,16 +14,18 @@ import fr.acinq.lightning.channel.states.WaitForFundingCreated
 import fr.acinq.lightning.db.IncomingPayment
 import fr.acinq.lightning.utils.sum
 import fr.acinq.lightning.wire.Init
-import fr.acinq.lightning.wire.PleaseOpenChannel
-import kotlinx.coroutines.CompletableDeferred
 
 sealed interface NodeEvents
 
 data class PeerConnected(val remoteNodeId: PublicKey, val theirInit: Init) : 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 amountBeforeFees: Satoshi, val fees: ChannelManagementFees) : SwapInEvents {
+        val receivedAmount: Satoshi = amountBeforeFees - fees.total
+    }
 }
 
 sealed interface ChannelEvents : NodeEvents {
@@ -30,6 +35,7 @@ sealed interface ChannelEvents : NodeEvents {
 }
 
 sealed interface LiquidityEvents : NodeEvents {
+    /** Amount of liquidity purchased, before fees are paid. */
     val amount: MilliSatoshi
     val fee: MilliSatoshi
     val source: Source
@@ -42,11 +48,13 @@ 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 object NoMatchingFundingRate : Reason()
+            data class MissingOffChainAmountTooLow(val missingOffChainAmount: MilliSatoshi) : Reason()
+            data class TooManyParts(val parts: Int) : 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. */
@@ -59,15 +67,14 @@ 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. */
 data object UpgradeRequired : NodeEvents
 
 sealed interface PaymentEvents : NodeEvents {
     data class PaymentReceived(val paymentHash: ByteVector32, val receivedWith: List<IncomingPayment.ReceivedWith>) : PaymentEvents {
-        val amount: MilliSatoshi = receivedWith.map { it.amount }.sum()
+        val amount: MilliSatoshi = receivedWith.map { it.amountReceived }.sum()
         val fees: MilliSatoshi = receivedWith.map { it.fees }.sum()
     }
 }

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

@@ -12,6 +12,7 @@ import fr.acinq.lightning.payment.LiquidityPolicy
 import fr.acinq.lightning.utils.msat
 import fr.acinq.lightning.utils.sat
 import fr.acinq.lightning.utils.toMilliSatoshi
+import fr.acinq.lightning.wire.LiquidityAds
 import fr.acinq.lightning.wire.OfferTypes
 import io.ktor.utils.io.charsets.*
 import io.ktor.utils.io.core.*
@@ -172,6 +173,8 @@ data class NodeParams(
         require(!features.hasFeature(Feature.ZeroConfChannels)) { "${Feature.ZeroConfChannels.rfcName} has been deprecated: use the zeroConfPeers whitelist instead" }
         require(!features.hasFeature(Feature.TrustedSwapInClient)) { "${Feature.TrustedSwapInClient.rfcName} has been deprecated" }
         require(!features.hasFeature(Feature.TrustedSwapInProvider)) { "${Feature.TrustedSwapInProvider.rfcName} has been deprecated" }
+        require(!features.hasFeature(Feature.PayToOpenClient)) { "${Feature.PayToOpenClient.rfcName} has been deprecated" }
+        require(!features.hasFeature(Feature.PayToOpenProvider)) { "${Feature.PayToOpenProvider.rfcName} has been deprecated" }
         Features.validateFeatureGraph(features)
     }
 
@@ -193,15 +196,15 @@ data class NodeParams(
             Feature.RouteBlinding to FeatureSupport.Optional,
             Feature.DualFunding to FeatureSupport.Mandatory,
             Feature.ShutdownAnySegwit to FeatureSupport.Mandatory,
+            Feature.Quiescence 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.OnTheFlyFunding to FeatureSupport.Optional,
         ),
         dustLimit = 546.sat,
         maxRemoteDustLimit = 600.sat,
@@ -229,7 +232,7 @@ 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)),
         minFinalCltvExpiryDelta = Bolt11Invoice.DEFAULT_MIN_FINAL_EXPIRY_DELTA,
         maxFinalCltvExpiryDelta = CltvExpiryDelta(360),
         bolt12invoiceExpiry = 60.seconds,

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.AddWalletInputsToChannel
 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()
 }
 
@@ -33,20 +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): AddWalletInputsToChannel? = 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.unconfirmed.filter { cmd.trustedTxs.contains(it.outPoint.txid) })
-                addAll(availableWallet.weaklyConfirmed.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)
+                AddWalletInputsToChannel(utxos)
             } else {
                 null
             }

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

@@ -1,14 +1,15 @@
 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
 import fr.acinq.lightning.transactions.Transactions
 import fr.acinq.lightning.utils.UUID
+import fr.acinq.lightning.utils.toMilliSatoshi
 import fr.acinq.lightning.wire.*
 
 /** Channel Actions (outputs produced by the state machine). */
@@ -78,16 +79,16 @@ sealed class ChannelAction {
             abstract val origin: Origin?
             abstract val txId: TxId
             abstract val localInputs: Set<OutPoint>
-            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()
+            data class ViaNewChannel(val amountReceived: 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 amountReceived: MilliSatoshi, val serviceFee: MilliSatoshi, val miningFee: Satoshi, override val localInputs: Set<OutPoint>, override val txId: TxId, override val origin: Origin?) : StoreIncomingPayment()
         }
         /** Payment sent through on-chain operations (channel close or splice-out) */
         sealed class StoreOutgoingPayment : Storage() {
             abstract val miningFees: Satoshi
             abstract val txId: TxId
             data class ViaSpliceOut(val amount: Satoshi, override val miningFees: Satoshi, val address: String, override val txId: TxId) : StoreOutgoingPayment()
             data class ViaSpliceCpfp(override val miningFees: Satoshi, override val txId: TxId) : StoreOutgoingPayment()
-            data class ViaInboundLiquidityRequest(override val txId: TxId, override val miningFees: Satoshi, val lease: LiquidityAds.Lease) : StoreOutgoingPayment()
+            data class ViaInboundLiquidityRequest(override val txId: TxId, override val miningFees: Satoshi, val purchase: LiquidityAds.Purchase) : StoreOutgoingPayment()
             data class ViaClose(val amount: Satoshi, override val miningFees: Satoshi, val address: String, override val txId: TxId, val isSentToDefaultAddress: Boolean, val closingType: ChannelClosingType) : StoreOutgoingPayment()
         }
         data class SetLocked(val txId: TxId) : Storage()
@@ -128,8 +129,8 @@ 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.RequestFunding?,
+            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 fundingRates: LiquidityAds.WillFundRates?
         ) : Init()
 
         data class Restore(val state: PersistedChannelState) : Init()
@@ -85,7 +87,7 @@ sealed class ChannelCommand {
         data class UpdateFee(val feerate: FeeratePerKw, val commit: Boolean = false) : Commitment(), ForbiddenDuringSplice, ForbiddenDuringQuiescence
         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.RequestFunding?, 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()
 
@@ -104,7 +106,7 @@ sealed class ChannelCommand {
                     val fundingTxId: TxId,
                     val capacity: Satoshi,
                     val balance: MilliSatoshi,
-                    val liquidityLease: LiquidityAds.Lease?,
+                    val liquidityPurchase: LiquidityAds.Purchase?,
                 ) : Response()
 
                 sealed class Failure : Response() {