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Add liquidity ads to the channel opening flow
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We previously only used liquidity ads with splicing: we now support it
during the initial channel opening flow as well. This lets us add more
unit tests, including tests for the case where the node receiving the
`open_channel` message is responsible for paying the commitment fees.

We also update liquidity ads to use the latest version of the spec from
lightning/bolts#1153. This introduces more ways
of paying the liquidity fees, to support on-the-fly funding without
existing channel balance (not implemented in this commit).

Note that we need some backwards-compatibility with the previous
liquidity ads types in our state serialization code: when we're in the
middle of signing a splice transaction, we may have a legacy liquidity
lease in our splice status. We ignore it when finalizing the splice: the
only consequence is that we won't store an entry in our DB for that
lease, but the channel will otherwise work correctly.
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@t-bast
t-bast committed Jun 14, 2024
1 parent 7c3d782 commit b2c2df8
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Showing 50 changed files with 1,051 additions and 471 deletions.
5 changes: 3 additions & 2 deletions src/commonMain/kotlin/fr/acinq/lightning/NodeParams.kt
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Original file line number Diff line number Diff line change
Expand Up @@ -70,14 +70,15 @@ object DefaultSwapInParams {
* @param trampolineFees ordered list of trampoline fees to try when making an outgoing payment.
* @param invoiceDefaultRoutingFees default routing fees set in invoices when we don't have any channel.
* @param swapInParams parameters for swap-in transactions.
* @param leaseRate rate at which our peer sells their liquidity.
* @param remoteFundingRates rates at which our peer sells their liquidity.
*/
data class WalletParams(
val trampolineNode: NodeUri,
val trampolineFees: List<TrampolineFees>,
val invoiceDefaultRoutingFees: InvoiceDefaultRoutingFees,
val swapInParams: SwapInParams,
val leaseRate: LiquidityAds.LeaseRate,
// TODO: once standardized, we should get this data from our peer's init message.
val remoteFundingRates: LiquidityAds.WillFundRates,
)

/**
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7 changes: 4 additions & 3 deletions src/commonMain/kotlin/fr/acinq/lightning/channel/ChannelCommand.kt
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Original file line number Diff line number Diff line change
Expand Up @@ -35,7 +35,7 @@ sealed class ChannelCommand {
val channelFlags: ChannelFlags,
val channelConfig: ChannelConfig,
val channelType: ChannelType.SupportedChannelType,
val requestRemoteFunding: LiquidityAds.RequestRemoteFunding?,
val requestRemoteFunding: LiquidityAds.RequestFunding?,
val channelOrigin: Origin?,
) : Init() {
fun temporaryChannelId(keyManager: KeyManager): ByteVector32 = keyManager.channelKeys(localParams.fundingKeyPath).temporaryChannelId
Expand All @@ -48,7 +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()
Expand Down Expand Up @@ -86,7 +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>) : 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()

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1 change: 0 additions & 1 deletion src/commonMain/kotlin/fr/acinq/lightning/channel/ChannelException.kt
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Original file line number Diff line number Diff line change
Expand Up @@ -28,7 +28,6 @@ data class ToSelfDelayTooHigh (override val channelId: Byte
data class MissingLiquidityAds (override val channelId: ByteVector32) : ChannelException(channelId, "liquidity ads field is missing")
data class InvalidLiquidityAdsSig (override val channelId: ByteVector32) : ChannelException(channelId, "liquidity ads signature is invalid")
data class InvalidLiquidityAdsAmount (override val channelId: ByteVector32, val proposed: Satoshi, val min: Satoshi) : ChannelException(channelId, "liquidity ads funding amount is too low (expected at least $min, got $proposed)")
data class InvalidLiquidityRates (override val channelId: ByteVector32) : ChannelException(channelId, "rejecting liquidity ads proposed rates")
data class ChannelFundingError (override val channelId: ByteVector32) : ChannelException(channelId, "channel funding error")
data class RbfAttemptAborted (override val channelId: ByteVector32) : ChannelException(channelId, "rbf attempt aborted")
data class SpliceAborted (override val channelId: ByteVector32) : ChannelException(channelId, "splice aborted")
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20 changes: 13 additions & 7 deletions src/commonMain/kotlin/fr/acinq/lightning/channel/InteractiveTx.kt
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Original file line number Diff line number Diff line change
Expand Up @@ -673,8 +673,7 @@ data class InteractiveTxSession(
val isComplete: Boolean = txCompleteSent != null && txCompleteReceived != null

fun send(): Pair<InteractiveTxSession, InteractiveTxSessionAction> {
val msg = toSend.firstOrNull()
return when (msg) {
return when (val msg = toSend.firstOrNull()) {
null -> {
val localSwapIns = localInputs.filterIsInstance<InteractiveTxInput.LocalSwapIn>()
val remoteSwapIns = remoteInputs.filterIsInstance<InteractiveTxInput.RemoteSwapIn>()
Expand Down Expand Up @@ -987,7 +986,6 @@ data class InteractiveTxSigningSession(
val fundingParams: InteractiveTxParams,
val fundingTxIndex: Long,
val fundingTx: PartiallySignedSharedTransaction,
val liquidityLease: LiquidityAds.Lease?,
val localCommit: Either<UnsignedLocalCommit, LocalCommit>,
val remoteCommit: RemoteCommit,
) {
Expand Down Expand Up @@ -1075,7 +1073,15 @@ data class InteractiveTxSigningSession(
val channelKeys = channelParams.localParams.channelKeys(keyManager)
val unsignedTx = sharedTx.buildUnsignedTx()
val sharedOutputIndex = unsignedTx.txOut.indexOfFirst { it.publicKeyScript == fundingParams.fundingPubkeyScript(channelKeys) }
val liquidityFees = liquidityLease?.fees?.total?.toMilliSatoshi() ?: 0.msat
val liquidityFees = liquidityLease?.let { l ->
val fees = l.fees.total.toMilliSatoshi()
when (l.paymentDetails) {
is LiquidityAds.PaymentDetails.FromChannelBalance -> if (fundingParams.isInitiator) fees else -fees
// Fees will be paid later, from relayed HTLCs.
is LiquidityAds.PaymentDetails.FromFutureHtlc -> 0.msat
is LiquidityAds.PaymentDetails.FromFutureHtlcWithPreimage -> 0.msat
}
} ?: 0.msat
return Helpers.Funding.makeCommitTxs(
channelKeys,
channelParams.channelId,
Expand Down Expand Up @@ -1120,7 +1126,7 @@ data class InteractiveTxSigningSession(
val unsignedLocalCommit = UnsignedLocalCommit(localCommitmentIndex, firstCommitTx.localSpec, firstCommitTx.localCommitTx, listOf())
val remoteCommit = RemoteCommit(remoteCommitmentIndex, firstCommitTx.remoteSpec, firstCommitTx.remoteCommitTx.tx.txid, remotePerCommitmentPoint)
val signedFundingTx = sharedTx.sign(session, keyManager, fundingParams, channelParams.localParams, channelParams.remoteParams.nodeId)
Pair(InteractiveTxSigningSession(fundingParams, fundingTxIndex, signedFundingTx, liquidityLease, Either.Left(unsignedLocalCommit), remoteCommit), commitSig)
Pair(InteractiveTxSigningSession(fundingParams, fundingTxIndex, signedFundingTx, Either.Left(unsignedLocalCommit), remoteCommit), commitSig)
}
}

Expand Down Expand Up @@ -1168,7 +1174,7 @@ sealed class SpliceStatus {
/** Our peer has asked us to stop sending new updates and wait for our updates to be added to the local and remote commitments. */
data class ReceivedStfu(val stfu: Stfu) : QuiescenceNegotiation.NonInitiator()
/** Our updates have been added to the local and remote commitments, we wait for our peer to use the now quiescent channel. */
object NonInitiatorQuiescent : QuiescentSpliceStatus()
data object NonInitiatorQuiescent : QuiescentSpliceStatus()
/** We told our peer we want to splice funds in the channel. */
data class Requested(val command: ChannelCommand.Commitment.Splice.Request, val spliceInit: SpliceInit) : QuiescentSpliceStatus()
/** We both agreed to splice and are building the splice transaction. */
Expand All @@ -1181,7 +1187,7 @@ sealed class SpliceStatus {
val origins: List<Origin>
) : QuiescentSpliceStatus()
/** The splice transaction has been negotiated, we're exchanging signatures. */
data class WaitingForSigs(val session: InteractiveTxSigningSession, val origins: List<Origin>) : QuiescentSpliceStatus()
data class WaitingForSigs(val session: InteractiveTxSigningSession, val liquidityLease: LiquidityAds.Lease?, val origins: List<Origin>) : QuiescentSpliceStatus()
/** The splice attempt was aborted by us, we're waiting for our peer to ack. */
data object Aborted : QuiescentSpliceStatus()
}
1 change: 0 additions & 1 deletion src/commonMain/kotlin/fr/acinq/lightning/channel/states/LegacyWaitForFundingLocked.kt
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Original file line number Diff line number Diff line change
Expand Up @@ -48,7 +48,6 @@ data class LegacyWaitForFundingLocked(
null,
null,
SpliceStatus.None,
listOf(),
)
val actions = listOf(
ChannelAction.Storage.StoreState(nextState),
Expand Down
27 changes: 19 additions & 8 deletions src/commonMain/kotlin/fr/acinq/lightning/channel/states/Normal.kt
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Original file line number Diff line number Diff line change
Expand Up @@ -24,7 +24,6 @@ data class Normal(
val remoteShutdown: Shutdown?,
val closingFeerates: ClosingFeerates?,
val spliceStatus: SpliceStatus,
val liquidityLeases: List<LiquidityAds.Lease>,
) : ChannelStateWithCommitments() {

override fun updateCommitments(input: Commitments): ChannelStateWithCommitments = this.copy(commitments = input)
Expand Down Expand Up @@ -179,7 +178,7 @@ data class Normal(
logger.info { "waiting for tx_sigs" }
Pair(this@Normal.copy(spliceStatus = spliceStatus.copy(session = signingSession1)), listOf())
}
is InteractiveTxSigningSessionAction.SendTxSigs -> sendSpliceTxSigs(spliceStatus.origins, action, spliceStatus.session.liquidityLease, cmd.message.channelData)
is InteractiveTxSigningSessionAction.SendTxSigs -> sendSpliceTxSigs(spliceStatus.origins, action, spliceStatus.liquidityLease, cmd.message.channelData)
}
}
ignoreRetransmittedCommitSig(cmd.message) -> {
Expand Down Expand Up @@ -406,8 +405,8 @@ data class Normal(
add(ChannelAction.Disconnect)
}
Pair(this@Normal.copy(spliceStatus = SpliceStatus.None), actions)
} else if (spliceStatus.command.requestRemoteFunding?.let { r -> r.rate.fees(spliceStatus.command.feerate, r.fundingAmount, r.fundingAmount).total <= parentCommitment.localCommit.spec.toLocal.truncateToSatoshi() } == false) {
val missing = spliceStatus.command.requestRemoteFunding.let { r -> r.rate.fees(spliceStatus.command.feerate, r.fundingAmount, r.fundingAmount).total - parentCommitment.localCommit.spec.toLocal.truncateToSatoshi() }
} else if (!canAffordSpliceLiquidityFees(spliceStatus.command, parentCommitment)) {
val missing = spliceStatus.command.requestRemoteFunding?.let { r -> r.fees(spliceStatus.command.feerate).total - parentCommitment.localCommit.spec.toLocal.truncateToSatoshi() }
logger.warning { "cannot do splice: balance is too low to pay for inbound liquidity (missing=$missing)" }
spliceStatus.command.replyTo.complete(ChannelCommand.Commitment.Splice.Response.Failure.InsufficientFunds)
Pair(this@Normal, emptyList())
Expand All @@ -419,7 +418,7 @@ data class Normal(
feerate = spliceStatus.command.feerate,
fundingPubkey = channelKeys().fundingPubKey(parentCommitment.fundingTxIndex + 1),
pushAmount = spliceStatus.command.pushAmount,
requestFunds = spliceStatus.command.requestRemoteFunding?.requestFunds,
requestFunding = spliceStatus.command.requestRemoteFunding,
)
logger.info { "initiating splice with local.amount=${spliceInit.fundingContribution} local.push=${spliceInit.pushAmount}" }
Pair(this@Normal.copy(spliceStatus = SpliceStatus.Requested(spliceStatus.command, spliceInit)), listOf(ChannelAction.Message.Send(spliceInit)))
Expand Down Expand Up @@ -642,7 +641,7 @@ data class Normal(
liquidityLease = spliceStatus.liquidityLease,
)
)
val nextState = this@Normal.copy(spliceStatus = SpliceStatus.WaitingForSigs(session, spliceStatus.origins))
val nextState = this@Normal.copy(spliceStatus = SpliceStatus.WaitingForSigs(session, spliceStatus.liquidityLease, spliceStatus.origins))
val actions = buildList {
interactiveTxAction.txComplete?.let { add(ChannelAction.Message.Send(it)) }
add(ChannelAction.Storage.StoreState(nextState))
Expand Down Expand Up @@ -674,7 +673,7 @@ data class Normal(
}
is Either.Right -> {
val action: InteractiveTxSigningSessionAction.SendTxSigs = res.value
sendSpliceTxSigs(spliceStatus.origins, action, spliceStatus.session.liquidityLease, cmd.message.channelData)
sendSpliceTxSigs(spliceStatus.origins, action, spliceStatus.liquidityLease, cmd.message.channelData)
}
}
}
Expand Down Expand Up @@ -840,6 +839,18 @@ data class Normal(
}
}

private fun canAffordSpliceLiquidityFees(splice: ChannelCommand.Commitment.Splice.Request, parentCommitment: Commitment): Boolean {
return when (val request = splice.requestRemoteFunding) {
null -> true
else -> when (request.paymentDetails) {
is LiquidityAds.PaymentDetails.FromChannelBalance -> request.fees(splice.feerate).total <= parentCommitment.localCommit.spec.toLocal.truncateToSatoshi()
// Fees don't need to be paid during the splice, they will be deducted from relayed HTLCs.
is LiquidityAds.PaymentDetails.FromFutureHtlc -> true
is LiquidityAds.PaymentDetails.FromFutureHtlcWithPreimage -> true
}
}
}

private fun ChannelContext.sendSpliceTxSigs(
origins: List<Origin>,
action: InteractiveTxSigningSessionAction.SendTxSigs,
Expand All @@ -851,7 +862,7 @@ data class Normal(
val fundingMinDepth = Helpers.minDepthForFunding(staticParams.nodeParams, action.fundingTx.fundingParams.fundingAmount)
val watchConfirmed = WatchConfirmed(channelId, action.commitment.fundingTxId, action.commitment.commitInput.txOut.publicKeyScript, fundingMinDepth.toLong(), BITCOIN_FUNDING_DEPTHOK)
val commitments = commitments.add(action.commitment).copy(remoteChannelData = remoteChannelData)
val nextState = this@Normal.copy(commitments = commitments, spliceStatus = SpliceStatus.None, liquidityLeases = liquidityLeases + listOfNotNull(liquidityLease))
val nextState = this@Normal.copy(commitments = commitments, spliceStatus = SpliceStatus.None)
val actions = buildList {
add(ChannelAction.Storage.StoreState(nextState))
action.fundingTx.signedTx?.let { add(ChannelAction.Blockchain.PublishTx(it, ChannelAction.Blockchain.PublishTx.Type.FundingTx)) }
Expand Down
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