Implement the interactive-tx protocol

eclair-core/src/main/scala/fr/acinq/eclair/blockchain/OnChainWallet.scala

@@ -17,7 +17,7 @@
 package fr.acinq.eclair.blockchain
 
 import fr.acinq.bitcoin.scalacompat.Crypto.PublicKey
-import fr.acinq.bitcoin.scalacompat.{Satoshi, Transaction}
+import fr.acinq.bitcoin.scalacompat.{ByteVector32, Satoshi, Transaction}
 import fr.acinq.eclair.blockchain.fee.FeeratePerKw
 import scodec.bits.ByteVector
 
@@ -30,10 +30,22 @@ import scala.concurrent.{ExecutionContext, Future}
 /** This trait lets users fund lightning channels. */
 trait OnChainChannelFunder {
 
-  import OnChainWallet.MakeFundingTxResponse
+  import OnChainWallet._
 
-  /** Create a channel funding transaction with the provided pubkeyScript. */
-  def makeFundingTx(pubkeyScript: ByteVector, amount: Satoshi, feeRatePerKw: FeeratePerKw)(implicit ec: ExecutionContext): Future[MakeFundingTxResponse]
+  /** Fund the provided transaction by adding inputs (and a change output if necessary). */
+  def fundTransaction(tx: Transaction, feeRate: FeeratePerKw, replaceable: Boolean, lockUtxos: Boolean)(implicit ec: ExecutionContext): Future[FundTransactionResponse]
+
+  /** Sign the wallet inputs of the provided transaction. */
+  def signTransaction(tx: Transaction, allowIncomplete: Boolean)(implicit ec: ExecutionContext): Future[SignTransactionResponse]
+
+  /**
+   * Publish a transaction on the bitcoin network.
+   * This method must be idempotent: if the tx was already published, it must return a success.
+   */
+  def publishTransaction(tx: Transaction)(implicit ec: ExecutionContext): Future[ByteVector32]
+
+  /** Create a fully signed channel funding transaction with the provided pubkeyScript. */
+  def makeFundingTx(pubkeyScript: ByteVector, amount: Satoshi, feeRate: FeeratePerKw)(implicit ec: ExecutionContext): Future[MakeFundingTxResponse]
 
   /**
    * Committing *must* include publishing the transaction on the network.
@@ -47,9 +59,10 @@ trait OnChainChannelFunder {
    */
   def commit(tx: Transaction)(implicit ec: ExecutionContext): Future[Boolean]
 
-  /**
-   * Rollback a transaction that we failed to commit: this probably translates to "release locks on utxos".
-   */
+  /** Return the transaction if it exists, either in the blockchain or in the mempool. */
+  def getTransaction(txId: ByteVector32)(implicit ec: ExecutionContext): Future[Transaction]
+
+  /** Rollback a transaction that we failed to commit: this probably translates to "release locks on utxos". */
   def rollback(tx: Transaction)(implicit ec: ExecutionContext): Future[Boolean]
 
   /**
@@ -97,4 +110,10 @@ object OnChainWallet {
 
   final case class MakeFundingTxResponse(fundingTx: Transaction, fundingTxOutputIndex: Int, fee: Satoshi)
 
+  final case class FundTransactionResponse(tx: Transaction, fee: Satoshi, changePosition: Option[Int]) {
+    val amountIn: Satoshi = fee + tx.txOut.map(_.amount).sum
+  }
+
+  final case class SignTransactionResponse(tx: Transaction, complete: Boolean)
+
 }

eclair-core/src/main/scala/fr/acinq/eclair/blockchain/bitcoind/rpc/BitcoinCoreClient.scala

@@ -21,7 +21,7 @@ import fr.acinq.bitcoin.scalacompat._
 import fr.acinq.bitcoin.{Bech32, Block}
 import fr.acinq.eclair.ShortChannelId.coordinates
 import fr.acinq.eclair.blockchain.OnChainWallet
-import fr.acinq.eclair.blockchain.OnChainWallet.{MakeFundingTxResponse, OnChainBalance}
+import fr.acinq.eclair.blockchain.OnChainWallet.{FundTransactionResponse, MakeFundingTxResponse, OnChainBalance, SignTransactionResponse}
 import fr.acinq.eclair.blockchain.bitcoind.ZmqWatcher.{GetTxWithMetaResponse, UtxoStatus, ValidateResult}
 import fr.acinq.eclair.blockchain.fee.{FeeratePerKB, FeeratePerKw}
 import fr.acinq.eclair.transactions.Transactions
@@ -220,6 +220,10 @@ class BitcoinCoreClient(val rpcClient: BitcoinJsonRPCClient) extends OnChainWall
     })
   }
 
+  def fundTransaction(tx: Transaction, feeRate: FeeratePerKw, replaceable: Boolean, lockUtxos: Boolean)(implicit ec: ExecutionContext): Future[FundTransactionResponse] = {
+    fundTransaction(tx, FundTransactionOptions(feeRate, replaceable, lockUtxos))
+  }
+
   def makeFundingTx(pubkeyScript: ByteVector, amount: Satoshi, targetFeerate: FeeratePerKw)(implicit ec: ExecutionContext): Future[MakeFundingTxResponse] = {
     val partialFundingTx = Transaction(
       version = 2,
@@ -255,11 +259,12 @@ class BitcoinCoreClient(val rpcClient: BitcoinJsonRPCClient) extends OnChainWall
 
   def signTransaction(tx: Transaction)(implicit ec: ExecutionContext): Future[SignTransactionResponse] = signTransaction(tx, Nil)
 
+  def signTransaction(tx: Transaction, allowIncomplete: Boolean)(implicit ec: ExecutionContext): Future[SignTransactionResponse] = signTransaction(tx, Nil, allowIncomplete)
+
   def signTransaction(tx: Transaction, previousTxs: Seq[PreviousTx], allowIncomplete: Boolean = false)(implicit ec: ExecutionContext): Future[SignTransactionResponse] = {
     rpcClient.invoke("signrawtransactionwithwallet", tx.toString(), previousTxs).map(json => {
       val JString(hex) = json \ "hex"
       val JBool(complete) = json \ "complete"
-      // TODO: remove allowIncomplete once /~https://github.com/bitcoin/bitcoin/issues/21151 is fixed
       if (!complete && !allowIncomplete) {
         val JArray(errors) = json \ "errors"
         val message = errors.map(error => {
@@ -336,7 +341,6 @@ class BitcoinCoreClient(val rpcClient: BitcoinJsonRPCClient) extends OnChainWall
           case Failure(JsonRPCError(error)) if error.message.contains("expected locked output") =>
             Future.successful(true) // we consider that the outpoint was successfully unlocked (since it was not locked to begin with)
           case Failure(t) =>
-            logger.warn(s"cannot unlock utxo=$utxo:", t)
             Future.successful(false)
         })
     val future = Future.sequence(futures)
@@ -473,10 +477,6 @@ object BitcoinCoreClient {
     }
   }
 
-  case class FundTransactionResponse(tx: Transaction, fee: Satoshi, changePosition: Option[Int]) {
-    val amountIn: Satoshi = fee + tx.txOut.map(_.amount).sum
-  }
-
   case class PreviousTx(txid: ByteVector32, vout: Long, scriptPubKey: String, redeemScript: String, witnessScript: String, amount: BigDecimal)
 
   object PreviousTx {
@@ -490,8 +490,6 @@ object BitcoinCoreClient {
     )
   }
 
-  case class SignTransactionResponse(tx: Transaction, complete: Boolean)
-
   /**
    * Information about a transaction currently in the mempool.
    *

eclair-core/src/main/scala/fr/acinq/eclair/channel/ChannelData.scala

@@ -16,10 +16,12 @@
 
 package fr.acinq.eclair.channel
 
+import akka.actor.typed
 import akka.actor.{ActorRef, PossiblyHarmful}
 import fr.acinq.bitcoin.scalacompat.Crypto.PublicKey
 import fr.acinq.bitcoin.scalacompat.{ByteVector32, DeterministicWallet, OutPoint, Satoshi, Transaction}
 import fr.acinq.eclair.blockchain.fee.FeeratePerKw
+import fr.acinq.eclair.channel.InteractiveTxBuilder.{InteractiveTxParams, SignedSharedTransaction}
 import fr.acinq.eclair.payment.OutgoingPaymentPacket.Upstream
 import fr.acinq.eclair.transactions.CommitmentSpec
 import fr.acinq.eclair.transactions.Transactions._
@@ -60,7 +62,8 @@ case object WAIT_FOR_CHANNEL_READY extends ChannelState
 case object WAIT_FOR_INIT_DUAL_FUNDED_CHANNEL extends ChannelState
 case object WAIT_FOR_OPEN_DUAL_FUNDED_CHANNEL extends ChannelState
 case object WAIT_FOR_ACCEPT_DUAL_FUNDED_CHANNEL extends ChannelState
-case object WAIT_FOR_DUAL_FUNDING_INTERNAL extends ChannelState
+case object WAIT_FOR_DUAL_FUNDING_CREATED extends ChannelState
+case object WAIT_FOR_DUAL_FUNDING_PLACEHOLDER extends ChannelState
 // Channel opened:
 case object NORMAL extends ChannelState
 case object SHUTDOWN extends ChannelState
@@ -397,6 +400,9 @@ object RealScidStatus {
  */
 case class ShortIds(real: RealScidStatus, localAlias: Alias, remoteAlias_opt: Option[Alias])
 
+/** Once a dual funding tx has been signed, we must remember the associated commitments. */
+case class DualFundingTx(fundingTx: SignedSharedTransaction, commitments: Commitments)
+
 sealed trait ChannelData extends PossiblyHarmful {
   def channelId: ByteVector32
 }
@@ -470,10 +476,19 @@ final case class DATA_WAIT_FOR_OPEN_DUAL_FUNDED_CHANNEL(init: INPUT_INIT_CHANNEL
 final case class DATA_WAIT_FOR_ACCEPT_DUAL_FUNDED_CHANNEL(init: INPUT_INIT_CHANNEL_INITIATOR, lastSent: OpenDualFundedChannel) extends TransientChannelData {
   val channelId: ByteVector32 = lastSent.temporaryChannelId
 }
-final case class DATA_WAIT_FOR_DUAL_FUNDING_INTERNAL(channelId: ByteVector32,
-                                                     localParams: LocalParams,
-                                                     remoteParams: RemoteParams,
-                                                     channelFeatures: ChannelFeatures) extends TransientChannelData
+final case class DATA_WAIT_FOR_DUAL_FUNDING_CREATED(channelId: ByteVector32,
+                                                    txBuilder: typed.ActorRef[InteractiveTxBuilder.Command],
+                                                    deferred: Option[ChannelReady]) extends TransientChannelData
+final case class DATA_WAIT_FOR_DUAL_FUNDING_PLACEHOLDER(commitments: Commitments,
+                                                        fundingTx: SignedSharedTransaction,
+                                                        fundingParams: InteractiveTxParams,
+                                                        previousFundingTxs: Seq[DualFundingTx],
+                                                        waitingSince: BlockHeight, // how long have we been waiting for a funding tx to confirm
+                                                        lastChecked: BlockHeight, // last time we checked if the channel was double-spent
+                                                        rbfAttempt: Option[typed.ActorRef[InteractiveTxBuilder.Command]],
+                                                        deferred: Option[ChannelReady]) extends TransientChannelData {
+  val channelId: ByteVector32 = commitments.channelId
+}
 
 final case class DATA_NORMAL(commitments: Commitments,
                              shortIds: ShortIds,

eclair-core/src/main/scala/fr/acinq/eclair/channel/ChannelExceptions.scala

@@ -19,7 +19,7 @@ package fr.acinq.eclair.channel
 import fr.acinq.bitcoin.scalacompat.Crypto.PrivateKey
 import fr.acinq.bitcoin.scalacompat.{ByteVector32, Satoshi, Transaction}
 import fr.acinq.eclair.blockchain.fee.FeeratePerKw
-import fr.acinq.eclair.wire.protocol.{AnnouncementSignatures, Error, UpdateAddHtlc}
+import fr.acinq.eclair.wire.protocol.{AnnouncementSignatures, Error, InteractiveTxMessage, UpdateAddHtlc}
 import fr.acinq.eclair.{BlockHeight, CltvExpiry, CltvExpiryDelta, MilliSatoshi, UInt64}
 
 /**
@@ -50,6 +50,26 @@ case class ChannelReserveTooHigh                   (override val channelId: Byte
 case class ChannelReserveBelowOurDustLimit         (override val channelId: ByteVector32, channelReserve: Satoshi, dustLimit: Satoshi) extends ChannelException(channelId, s"their channelReserve=$channelReserve is below our dustLimit=$dustLimit")
 case class ChannelReserveNotMet                    (override val channelId: ByteVector32, toLocal: MilliSatoshi, toRemote: MilliSatoshi, reserve: Satoshi) extends ChannelException(channelId, s"channel reserve is not met toLocal=$toLocal toRemote=$toRemote reserve=$reserve")
 case class ChannelFundingError                     (override val channelId: ByteVector32) extends ChannelException(channelId, "channel funding error")
+case class InvalidSerialId                         (override val channelId: ByteVector32, serialId: UInt64) extends ChannelException(channelId, s"invalid serial_id=${serialId.toByteVector.toHex}")
+case class DuplicateSerialId                       (override val channelId: ByteVector32, serialId: UInt64) extends ChannelException(channelId, s"duplicate serial_id=${serialId.toByteVector.toHex}")
+case class UnknownSerialId                         (override val channelId: ByteVector32, serialId: UInt64) extends ChannelException(channelId, s"unknown serial_id=${serialId.toByteVector.toHex}")
+case class DuplicateInput                          (override val channelId: ByteVector32, serialId: UInt64, previousTxId: ByteVector32, previousTxOutput: Long) extends ChannelException(channelId, s"duplicate input $previousTxId:$previousTxOutput (serial_id=${serialId.toByteVector.toHex})")
+case class InputOutOfBounds                        (override val channelId: ByteVector32, serialId: UInt64, previousTxId: ByteVector32, previousTxOutput: Long) extends ChannelException(channelId, s"invalid input $previousTxId:$previousTxOutput (serial_id=${serialId.toByteVector.toHex})")
+case class NonSegwitInput                          (override val channelId: ByteVector32, serialId: UInt64, previousTxId: ByteVector32, previousTxOutput: Long) extends ChannelException(channelId, s"$previousTxId:$previousTxOutput is not a native segwit input (serial_id=${serialId.toByteVector.toHex})")
+case class OutputBelowDust                         (override val channelId: ByteVector32, serialId: UInt64, amount: Satoshi, dustLimit: Satoshi) extends ChannelException(channelId, s"invalid output amount=$amount below dust=$dustLimit (serial_id=${serialId.toByteVector.toHex})")
+case class NonSegwitOutput                         (override val channelId: ByteVector32, serialId: UInt64) extends ChannelException(channelId, s"output with serial_id=${serialId.toByteVector.toHex} is not a native segwit output")
+case class InvalidCompleteInteractiveTx            (override val channelId: ByteVector32) extends ChannelException(channelId, "the completed interactive tx is invalid")
+case class TooManyInteractiveTxRounds              (override val channelId: ByteVector32) extends ChannelException(channelId, "too many messages exchanged during interactive tx construction")
+case class DualFundingAborted                      (override val channelId: ByteVector32) extends ChannelException(channelId, "dual funding aborted")
+case class UnexpectedInteractiveTxMessage          (override val channelId: ByteVector32, msg: InteractiveTxMessage) extends ChannelException(channelId, s"unexpected interactive-tx message (${msg.getClass.getSimpleName})")
+case class UnexpectedCommitSig                     (override val channelId: ByteVector32) extends ChannelException(channelId, "unexpected commitment signatures (commit_sig)")
+case class UnexpectedFundingSignatures             (override val channelId: ByteVector32) extends ChannelException(channelId, "unexpected funding signatures (tx_signatures)")
+case class InvalidFundingFeerate                   (override val channelId: ByteVector32, targetFeerate: FeeratePerKw, actualFeerate: FeeratePerKw) extends ChannelException(channelId, s"invalid funding feerate: target=$targetFeerate actual=$actualFeerate")
+case class InvalidFundingSignature                 (override val channelId: ByteVector32, tx_opt: Option[Transaction]) extends ChannelException(channelId, s"invalid funding signature: tx=${tx_opt.map(_.toString()).getOrElse("n/a")}")
+case class InvalidRbfFeerate                       (override val channelId: ByteVector32, proposed: FeeratePerKw, expected: FeeratePerKw) extends ChannelException(channelId, s"invalid rbf attempt: the feerate must be at least $expected, you proposed $proposed")
+case class InvalidRbfAlreadyInProgress             (override val channelId: ByteVector32) extends ChannelException(channelId, "invalid rbf attempt: the current rbf attempt must be completed or aborted first")
+case class InvalidRbfTxConfirmed                   (override val channelId: ByteVector32) extends ChannelException(channelId, "no need to rbf, transaction is already confirmed")
+case class InvalidRbfAttempt                       (override val channelId: ByteVector32) extends ChannelException(channelId, "invalid rbf attempt")
 case class NoMoreHtlcsClosingInProgress            (override val channelId: ByteVector32) extends ChannelException(channelId, "cannot send new htlcs, closing in progress")
 case class NoMoreFeeUpdateClosingInProgress        (override val channelId: ByteVector32) extends ChannelException(channelId, "cannot send new update_fee, closing in progress")
 case class ClosingAlreadyInProgress                (override val channelId: ByteVector32) extends ChannelException(channelId, "closing already in progress")
@@ -59,6 +79,7 @@ case class ChannelUnavailable                      (override val channelId: Byte
 case class InvalidFinalScript                      (override val channelId: ByteVector32) extends ChannelException(channelId, "invalid final script")
 case class MissingUpfrontShutdownScript            (override val channelId: ByteVector32) extends ChannelException(channelId, "missing upfront shutdown script")
 case class FundingTxTimedout                       (override val channelId: ByteVector32) extends ChannelException(channelId, "funding tx timed out")
+case class FundingTxDoubleSpent                    (override val channelId: ByteVector32) extends ChannelException(channelId, "funding tx double spent")
 case class FundingTxSpent                          (override val channelId: ByteVector32, spendingTx: Transaction) extends ChannelException(channelId, s"funding tx has been spent by txid=${spendingTx.txid}")
 case class HtlcsTimedoutDownstream                 (override val channelId: ByteVector32, htlcs: Set[UpdateAddHtlc]) extends ChannelException(channelId, s"one or more htlcs timed out downstream: ids=${htlcs.take(10).map(_.id).mkString(",")}") // we only display the first 10 ids
 case class HtlcsWillTimeoutUpstream                (override val channelId: ByteVector32, htlcs: Set[UpdateAddHtlc]) extends ChannelException(channelId, s"one or more htlcs that should be fulfilled are close to timing out upstream: ids=${htlcs.take(10).map(_.id).mkString}") // we only display the first 10 ids