Remove support for push_amount

With the updated on-the-fly funding protocol, we're using liquidity ads
instead of an unofficial `push_amount` TLV. We can thus remove usage of
`push_amount`s everywhere, which simplifies the codebase.

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

@@ -10,7 +10,6 @@ import fr.acinq.lightning.channel.states.ClosingFeerates
 import fr.acinq.lightning.channel.states.PersistedChannelState
 import fr.acinq.lightning.crypto.KeyManager
 import fr.acinq.lightning.utils.UUID
-import fr.acinq.lightning.utils.msat
 import fr.acinq.lightning.wire.FailureMessage
 import fr.acinq.lightning.wire.LightningMessage
 import fr.acinq.lightning.wire.LiquidityAds
@@ -27,7 +26,6 @@ sealed class ChannelCommand {
  data class Initiator(
  val replyTo: CompletableDeferred<ChannelFundingResponse>,
  val fundingAmount: Satoshi,
- val pushAmount: MilliSatoshi,
  val walletInputs: List<WalletState.Utxo>,
  val commitTxFeerate: FeeratePerKw,
  val fundingTxFeerate: FeeratePerKw,
@@ -46,7 +44,6 @@ sealed class ChannelCommand {
  val replyTo: CompletableDeferred<ChannelFundingResponse>,
  val temporaryChannelId: ByteVector32,
  val fundingAmount: Satoshi,
- val pushAmount: MilliSatoshi,
  val walletInputs: List<WalletState.Utxo>,
  val localParams: LocalParams,
  val channelConfig: ChannelConfig,
@@ -98,11 +95,10 @@ sealed class ChannelCommand {
  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()
  val liquidityFees: LiquidityAds.Fees? = requestRemoteFunding?.fees(feerate, isChannelCreation = false)
 
- data class SpliceIn(val walletInputs: List<WalletState.Utxo>, val pushAmount: MilliSatoshi = 0.msat)
+ data class SpliceIn(val walletInputs: List<WalletState.Utxo>)
  data class SpliceOut(val amount: Satoshi, val scriptPubKey: ByteVector)
  }
  }

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

@@ -72,11 +72,6 @@ object Helpers {
  return Either.Left(InvalidChainHash(open.temporaryChannelId, local = nodeParams.chainHash, remote = open.chainHash))
  }
 
- // BOLT #2: The receiving node MUST fail the channel if: push_msat is greater than funding_satoshis * 1000.
- if (open.pushAmount > open.fundingAmount) {
- return Either.Left(InvalidPushAmount(open.temporaryChannelId, open.pushAmount, open.fundingAmount.toMilliSatoshi()))
- }
-
  // BOLT #2: The receiving node MUST fail the channel if: to_self_delay is unreasonably large.
  if (open.toSelfDelay > Channel.MAX_TO_SELF_DELAY || open.toSelfDelay > nodeParams.maxToLocalDelayBlocks) {
  return Either.Left(ToSelfDelayTooHigh(open.temporaryChannelId, open.toSelfDelay, nodeParams.maxToLocalDelayBlocks))
@@ -122,10 +117,6 @@ object Helpers {
  return Either.Left(InvalidFundingAmount(accept.temporaryChannelId, accept.fundingAmount))
  }
 
- if (accept.pushAmount > accept.fundingAmount) {
- return Either.Left(InvalidPushAmount(accept.temporaryChannelId, accept.pushAmount, accept.fundingAmount.toMilliSatoshi()))
- }
-
  if (accept.maxAcceptedHtlcs > Channel.MAX_ACCEPTED_HTLCS) {
  return Either.Left(InvalidMaxAcceptedHtlcs(accept.temporaryChannelId, accept.maxAcceptedHtlcs, Channel.MAX_ACCEPTED_HTLCS))
  }

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

@@ -270,11 +270,9 @@ data class FundingContributions(val inputs: List<InteractiveTxInput.Outgoing>, v
  swapInKeys: KeyManager.SwapInOnChainKeys,
  params: InteractiveTxParams,
  walletInputs: List<WalletState.Utxo>,
- localPushAmount: MilliSatoshi,
- remotePushAmount: MilliSatoshi,
  liquidityPurchase: LiquidityAds.Purchase?
  ): Either<FundingContributionFailure, FundingContributions> {
- return create(channelKeys, swapInKeys, params, null, walletInputs, listOf(), localPushAmount, remotePushAmount, liquidityPurchase)
+ return create(channelKeys, swapInKeys, params, null, walletInputs, listOf(), liquidityPurchase)
  }
 
  /**
@@ -290,8 +288,6 @@ data class FundingContributions(val inputs: List<InteractiveTxInput.Outgoing>, v
  sharedUtxo: Pair<SharedFundingInput, SharedFundingInputBalances>?,
  walletInputs: List<WalletState.Utxo>,
  localOutputs: List<TxOut>,
- localPushAmount: MilliSatoshi,
- remotePushAmount: MilliSatoshi,
  liquidityPurchase: LiquidityAds.Purchase?,
  changePubKey: PublicKey? = null
  ): Either<FundingContributionFailure, FundingContributions> {
@@ -310,9 +306,9 @@ data class FundingContributions(val inputs: List<InteractiveTxInput.Outgoing>, v
 
  val liquidityFees = params.liquidityFees(liquidityPurchase)
  val nextLocalBalanceBeforePush = (sharedUtxo?.second?.toLocal ?: 0.msat) + params.localContribution.toMilliSatoshi()
- val nextLocalBalanceAfterPush = (sharedUtxo?.second?.toLocal ?: 0.msat) + params.localContribution.toMilliSatoshi() - localPushAmount + remotePushAmount - liquidityFees
+ val nextLocalBalanceAfterPush = (sharedUtxo?.second?.toLocal ?: 0.msat) + params.localContribution.toMilliSatoshi() - liquidityFees
  val nextRemoteBalanceBeforePush = (sharedUtxo?.second?.toRemote ?: 0.msat) + params.remoteContribution.toMilliSatoshi()
- val nextRemoteBalanceAfterPush = (sharedUtxo?.second?.toRemote ?: 0.msat) + params.remoteContribution.toMilliSatoshi() + localPushAmount - remotePushAmount + liquidityFees
+ val nextRemoteBalanceAfterPush = (sharedUtxo?.second?.toRemote ?: 0.msat) + params.remoteContribution.toMilliSatoshi() + liquidityFees
  if (nextLocalBalanceAfterPush < 0.msat || nextRemoteBalanceAfterPush < 0.msat) {
  return Either.Left(FundingContributionFailure.InvalidFundingBalances(params.fundingAmount, nextLocalBalanceAfterPush, nextRemoteBalanceAfterPush))
  }
@@ -1091,8 +1087,6 @@ data class InteractiveTxSigningSession(
  fundingParams: InteractiveTxParams,
  fundingTxIndex: Long,
  sharedTx: SharedTransaction,
- localPushAmount: MilliSatoshi,
- remotePushAmount: MilliSatoshi,
  liquidityPurchase: LiquidityAds.Purchase?,
  localCommitmentIndex: Long,
  remoteCommitmentIndex: Long,
@@ -1109,8 +1103,8 @@ data class InteractiveTxSigningSession(
  channelParams.channelId,
  channelParams.localParams, channelParams.remoteParams,
  fundingAmount = sharedTx.sharedOutput.amount,
- toLocal = sharedTx.sharedOutput.localAmount - localPushAmount + remotePushAmount - liquidityFees,
- toRemote = sharedTx.sharedOutput.remoteAmount - remotePushAmount + localPushAmount + liquidityFees,
+ toLocal = sharedTx.sharedOutput.localAmount - liquidityFees,
+ toRemote = sharedTx.sharedOutput.remoteAmount + liquidityFees,
  localHtlcs = localHtlcs,
  localCommitmentIndex = localCommitmentIndex,
  remoteCommitmentIndex = remoteCommitmentIndex,
@@ -1203,8 +1197,6 @@ sealed class SpliceStatus {
  data class InProgress(
  val replyTo: CompletableDeferred<ChannelFundingResponse>?,
  val spliceSession: InteractiveTxSession,
- val localPushAmount: MilliSatoshi,
- val remotePushAmount: MilliSatoshi,
  val liquidityPurchase: LiquidityAds.Purchase?,
  val origins: List<Origin>
  ) : QuiescentSpliceStatus()

src/commonMain/kotlin/fr/acinq/lightning/channel/states/Normal.kt

@@ -419,10 +419,9 @@ data class Normal(
  lockTime = currentBlockHeight.toLong(),
  feerate = spliceStatus.command.feerate,
  fundingPubkey = channelKeys().fundingPubKey(parentCommitment.fundingTxIndex + 1),
- pushAmount = spliceStatus.command.pushAmount,
  requestFunding = spliceStatus.command.requestRemoteFunding,
  )
- logger.info { "initiating splice with local.amount=${spliceInit.fundingContribution} local.push=${spliceInit.pushAmount}" }
+ logger.info { "initiating splice with local.amount=${spliceInit.fundingContribution}" }
  Pair(this@Normal.copy(spliceStatus = SpliceStatus.Requested(spliceStatus.command, spliceInit)), listOf(ChannelAction.Message.Send(spliceInit)))
  }
  } else {
@@ -453,12 +452,11 @@ data class Normal(
  }
  is SpliceStatus.NonInitiatorQuiescent ->
  if (commitments.isQuiescent()) {
- logger.info { "accepting splice with remote.amount=${cmd.message.fundingContribution} remote.push=${cmd.message.pushAmount}" }
+ logger.info { "accepting splice with remote.amount=${cmd.message.fundingContribution}" }
  val parentCommitment = commitments.active.first()
  val spliceAck = SpliceAck(
  channelId,
  fundingContribution = 0.sat, // only remote contributes to the splice
- pushAmount = 0.msat,
  fundingPubkey = channelKeys().fundingPubKey(parentCommitment.fundingTxIndex + 1),
  willFund = null,
  )
@@ -489,8 +487,6 @@ data class Normal(
  spliceStatus = SpliceStatus.InProgress(
  replyTo = null,
  session,
- localPushAmount = 0.msat,
- remotePushAmount = cmd.message.pushAmount,
  liquidityPurchase = null,
  origins = listOf()
  )
@@ -511,7 +507,7 @@ data class Normal(
  }
  is SpliceAck -> when (spliceStatus) {
  is SpliceStatus.Requested -> {
- logger.info { "our peer accepted our splice request with remote.amount=${cmd.message.fundingContribution} remote.push=${cmd.message.pushAmount} liquidityFees=${spliceStatus.command.liquidityFees}" }
+ logger.info { "our peer accepted our splice request with remote.amount=${cmd.message.fundingContribution} liquidityFees=${spliceStatus.command.liquidityFees}" }
  when (val liquidityPurchase = LiquidityAds.validateRemoteFunding(
  spliceStatus.command.requestRemoteFunding,
  remoteNodeId,
@@ -550,8 +546,6 @@ data class Normal(
  sharedUtxo = Pair(sharedInput, SharedFundingInputBalances(toLocal = parentCommitment.localCommit.spec.toLocal, toRemote = parentCommitment.localCommit.spec.toRemote, toHtlcs = parentCommitment.localCommit.spec.htlcs.map { it.add.amountMsat }.sum())),
  walletInputs = spliceStatus.command.spliceIn?.walletInputs ?: emptyList(),
  localOutputs = spliceStatus.command.spliceOutputs,
- localPushAmount = spliceStatus.spliceInit.pushAmount,
- remotePushAmount = cmd.message.pushAmount,
  liquidityPurchase = liquidityPurchase.value,
  changePubKey = null // we don't want a change output: we're spending every funds available
  )) {
@@ -579,8 +573,6 @@ data class Normal(
  spliceStatus = SpliceStatus.InProgress(
  replyTo = spliceStatus.command.replyTo,
  interactiveTxSession,
- localPushAmount = spliceStatus.spliceInit.pushAmount,
- remotePushAmount = cmd.message.pushAmount,
  liquidityPurchase = liquidityPurchase.value,
  origins = spliceStatus.command.origins,
  )
@@ -617,8 +609,6 @@ data class Normal(
  spliceStatus.spliceSession.fundingParams,
  fundingTxIndex = parentCommitment.fundingTxIndex + 1,
  interactiveTxAction.sharedTx,
- localPushAmount = spliceStatus.localPushAmount,
- remotePushAmount = spliceStatus.remotePushAmount,
  liquidityPurchase = spliceStatus.liquidityPurchase,
  localCommitmentIndex = parentCommitment.localCommit.index,
  remoteCommitmentIndex = parentCommitment.remoteCommit.index,

src/commonMain/kotlin/fr/acinq/lightning/channel/states/WaitForAcceptChannel.kt

@@ -72,8 +72,6 @@ data class WaitForAcceptChannel(
  keyManager.swapInOnChainWallet,
  fundingParams,
  init.walletInputs,
- lastSent.pushAmount,
- accept.pushAmount,
  liquidityPurchase.value
  )) {
  is Either.Left -> {
@@ -100,8 +98,6 @@ data class WaitForAcceptChannel(
  init.localParams,
  remoteParams,
  interactiveTxSession,
- lastSent.pushAmount,
- accept.pushAmount,
  lastSent.commitmentFeerate,
  accept.firstPerCommitmentPoint,
  accept.secondPerCommitmentPoint,

src/commonMain/kotlin/fr/acinq/lightning/channel/states/WaitForFundingConfirmed.kt

@@ -2,21 +2,17 @@ package fr.acinq.lightning.channel.states
 
 import fr.acinq.bitcoin.TxId
 import fr.acinq.bitcoin.utils.Either
-import fr.acinq.lightning.MilliSatoshi
 import fr.acinq.lightning.ShortChannelId
 import fr.acinq.lightning.blockchain.BITCOIN_FUNDING_DEPTHOK
 import fr.acinq.lightning.blockchain.WatchConfirmed
 import fr.acinq.lightning.blockchain.WatchEventConfirmed
 import fr.acinq.lightning.channel.*
 import fr.acinq.lightning.utils.msat
-import fr.acinq.lightning.utils.toMilliSatoshi
 import fr.acinq.lightning.wire.*
 
 /** We wait for the channel funding transaction to confirm. */
 data class WaitForFundingConfirmed(
  override val commitments: Commitments,
- val localPushAmount: MilliSatoshi,
- val remotePushAmount: MilliSatoshi,
  val waitingSinceBlock: Long, // how many blocks have we been waiting for the funding tx to confirm
  val deferred: ChannelReady?,
  // We can have at most one ongoing RBF attempt.
@@ -85,12 +81,6 @@ data class WaitForFundingConfirmed(
  if (cmd.message.feerate < minNextFeerate) {
  logger.info { "rejecting rbf attempt: the new feerate must be at least $minNextFeerate (proposed=${cmd.message.feerate})" }
  Pair(this@WaitForFundingConfirmed.copy(rbfStatus = RbfStatus.RbfAborted), listOf(ChannelAction.Message.Send(TxAbort(channelId, InvalidRbfFeerate(channelId, cmd.message.feerate, minNextFeerate).message))))
- } else if (cmd.message.fundingContribution.toMilliSatoshi() < remotePushAmount) {
- logger.info { "rejecting rbf attempt: invalid amount pushed (fundingAmount=${cmd.message.fundingContribution}, pushAmount=$remotePushAmount)" }
- Pair(
- this@WaitForFundingConfirmed.copy(rbfStatus = RbfStatus.RbfAborted),
- listOf(ChannelAction.Message.Send(TxAbort(channelId, InvalidPushAmount(channelId, remotePushAmount, cmd.message.fundingContribution.toMilliSatoshi()).message)))
- )
  } else {
  logger.info { "our peer wants to raise the feerate of the funding transaction (previous=${latestFundingTx.fundingParams.targetFeerate} target=${cmd.message.feerate})" }
  val fundingParams = InteractiveTxParams(
@@ -136,7 +126,7 @@ data class WaitForFundingConfirmed(
  latestFundingTx.fundingParams.dustLimit,
  rbfStatus.command.targetFeerate
  )
- when (val contributions = FundingContributions.create(channelKeys(), keyManager.swapInOnChainWallet, fundingParams, rbfStatus.command.walletInputs, 0.msat, 0.msat, null)) {
+ when (val contributions = FundingContributions.create(channelKeys(), keyManager.swapInOnChainWallet, fundingParams, rbfStatus.command.walletInputs, null)) {
  is Either.Left -> {
  logger.warning { "error creating funding contributions: ${contributions.value}" }
  Pair(this@WaitForFundingConfirmed.copy(rbfStatus = RbfStatus.RbfAborted), listOf(ChannelAction.Message.Send(TxAbort(channelId, ChannelFundingError(channelId).message))))
@@ -175,8 +165,6 @@ data class WaitForFundingConfirmed(
  rbfSession1.fundingParams,
  fundingTxIndex = replacedCommitment.fundingTxIndex,
  interactiveTxAction.sharedTx,
- localPushAmount,
- remotePushAmount,
  liquidityPurchase = null,
  localCommitmentIndex = replacedCommitment.localCommit.index,
  remoteCommitmentIndex = replacedCommitment.remoteCommit.index,
@@ -321,8 +309,6 @@ data class WaitForFundingConfirmed(
  val watchConfirmed = WatchConfirmed(channelId, action.commitment.fundingTxId, action.commitment.commitInput.txOut.publicKeyScript, fundingMinDepth.toLong(), BITCOIN_FUNDING_DEPTHOK)
  val nextState = WaitForFundingConfirmed(
  commitments.add(action.commitment).copy(remoteChannelData = remoteChannelData),
- localPushAmount,
- remotePushAmount,
  waitingSinceBlock,
  deferred,
  RbfStatus.None