Remove support for the legacy splicing protocol used by Phoenix

docs/release-notes/eclair-vnext.md

@@ -9,6 +9,39 @@
 With this release, eclair requires using Bitcoin Core 30.x.
 Newer versions of Bitcoin Core may be used, but have not been extensively tested.
 
+### Channel Splicing
+
+With this release, we add support for the final version of [splicing](https://github.com/lightning/bolts/pull/1160) that was recently added to the BOLTs.
+Splicing allows node operators to change the size of their existing channels, which makes it easier and more efficient to allocate liquidity where it is most needed.
+Most node operators can now have a single channel with each of their peer, which costs less on-chain fees and resources, and makes path-finding easier.
+
+The size of an existing channel can be increased with the `splicein` API:
+
+```sh
+eclair-cli splicein --channelId=<channel_id> --amountIn=<amount_satoshis>
+```
+
+Once that transaction confirms, the additional liquidity can be used to send outgoing payments.
+If the transaction doesn't confirm, the node operator can speed up confirmation with the `rbfsplice` API:
+
+```sh
+eclair-cli rbfsplice --channelId=<channel_id> --targetFeerateSatByte=<feerate_satoshis_per_byte> --fundingFeeBudgetSatoshis=<maximum_on_chain_fee_satoshis>
+```
+
+If the node operator wants to reduce the size of a channel, or send some of the channel funds to an on-chain address, they can use the `spliceout` API:
+
+```sh
+eclair-cli spliceout --channelId=<channel_id> --amountOut=<amount_satoshis> --scriptPubKey=<on_chain_address>
+```
+
+That operation can also be RBF-ed with the `rbfsplice` API to speed up confirmation if necessary.
+
+Note that when 0-conf is used for the channel, it is not possible to RBF splice transactions.
+Node operators should instead create a new splice transaction (with `splicein` or `spliceout`) to CPFP the previous transaction.
+
+Note that eclair had already introduced support for a splicing prototype in v0.9.0, which helped improve the BOLT proposal.
+We're removing support for the previous splicing prototype feature: users that depended on this protocol must upgrade to create official splice transactions.
+
 ### Remove support for non-anchor channels
 
 We remove the code used to support legacy channels that don't use anchor outputs or taproot.

eclair-core/src/main/resources/reference.conf

@@ -88,6 +88,7 @@ eclair {
     option_zeroconf = disabled
     keysend = disabled
     option_simple_close = optional
+    option_splice = optional
     trampoline_payment_prototype = disabled
     async_payment_prototype = disabled
     on_the_fly_funding = disabled

eclair-core/src/main/scala/fr/acinq/eclair/Features.scala

@@ -344,8 +344,7 @@ object Features {
     val mandatory = 28
   }
 
-  // TODO: this should also extend NodeFeature once the spec is finalized
-  case object Quiescence extends Feature with InitFeature {
+  case object Quiescence extends Feature with InitFeature with NodeFeature {
     val rfcName = "option_quiesce"
     val mandatory = 34
   }
@@ -395,6 +394,11 @@ object Features {
     val mandatory = 60
   }
 
+  case object Splicing extends Feature with InitFeature with NodeFeature {
+    val rfcName = "option_splice"
+    val mandatory = 62
+  }
+
   case object PhoenixZeroReserve extends Feature with InitFeature with ChannelTypeFeature with PermanentChannelFeature {
     val rfcName = "phoenix_zero_reserve"
     val mandatory = 128
@@ -423,12 +427,6 @@ object Features {
     val mandatory = 152
   }
 
-  // TODO: @pm47 custom splices implementation for phoenix, to be replaced once splices is spec-ed (currently reserved here: https://github.com/lightning/bolts/issues/605)
-  case object SplicePrototype extends Feature with InitFeature {
-    val rfcName = "splice_prototype"
-    val mandatory = 154
-  }
-
   case object SimpleTaprootChannelsPhoenix extends Feature with InitFeature with NodeFeature with ChannelTypeFeature {
     val rfcName = "option_simple_taproot_phoenix"
     val mandatory = 564
@@ -482,12 +480,12 @@ object Features {
     ZeroConf,
     KeySend,
     SimpleClose,
+    Splicing,
     SimpleTaprootChannelsPhoenix,
     SimpleTaprootChannelsStaging,
     WakeUpNotificationClient,
     TrampolinePaymentPrototype,
     AsyncPaymentPrototype,
-    SplicePrototype,
     OnTheFlyFunding,
     FundingFeeCredit,
     PhoenixZeroReserve
@@ -506,7 +504,6 @@ object Features {
     SimpleClose -> (ShutdownAnySegwit :: Nil),
     SimpleTaprootChannelsPhoenix -> (ChannelType :: SimpleClose :: Nil),
     AsyncPaymentPrototype -> (TrampolinePaymentPrototype :: Nil),
-    OnTheFlyFunding -> (SplicePrototype :: Nil),
     FundingFeeCredit -> (OnTheFlyFunding :: Nil)
   )
 

eclair-core/src/main/scala/fr/acinq/eclair/channel/fund/InteractiveTxBuilder.scala

@@ -1206,11 +1206,8 @@ object InteractiveTxSigningSession {
                             liquidityPurchase_opt: Option[LiquidityAds.PurchaseBasicInfo]) extends InteractiveTxSigningSession {
     val fundingTxId: TxId = fundingTx.txId
     val localCommitIndex: Long = localCommit.fold(_.index, _.index)
-    // This value tells our peer whether we need them to retransmit their commit_sig on reconnection or not.
-    val nextLocalCommitmentNumber: Long = localCommit match {
-      case Left(unsignedCommit) => unsignedCommit.index
-      case Right(commit) => commit.index + 1
-    }
+    // If we haven't received the remote commit_sig, we will request a retransmission on reconnection.
+    val retransmitRemoteCommitSig: Boolean = localCommit.isLeft
 
     def localFundingKey(channelKeys: ChannelKeys): PrivateKey = channelKeys.fundingKey(fundingTxIndex)
 

eclair-core/src/main/scala/fr/acinq/eclair/io/PeerConnection.scala

@@ -211,8 +211,8 @@ class PeerConnection(keyPair: KeyPair, conf: PeerConnection.Conf, switchboard: A
           case batch: CommitSigBatch =>
             // We insert a start_batch message to let our peer know how many commit_sig they will receive.
             d.transport forward StartBatch.commitSigBatch(batch.channelId, batch.batchSize)
-            batch.messages.foreach(msg => d.transport forward msg)
-          case msg => d.transport forward msg
+            batch.messages.foreach(msg => d.transport forward msg.copy(tlvStream = TlvStream(msg.tlvStream.records.filterNot(_.isInstanceOf[CommitSigTlv.ExperimentalBatchTlv]))))
+          case _ => d.transport forward msg
         }
         msg match {
           // If we send any channel management message to this peer, the connection should be persistent.
@@ -391,41 +391,6 @@ class PeerConnection(keyPair: KeyPair, conf: PeerConnection.Conf, switchboard: A
                 d.peer ! msg
                 stay() using d.copy(commitSigBatch_opt = None)
             }
-          case msg: CommitSig =>
-            // We keep supporting the experimental version of splicing that older Phoenix wallets use.
-            // Once we're confident that enough Phoenix users have upgraded, we should remove this branch.
-            msg.tlvStream.get[CommitSigTlv.ExperimentalBatchTlv].map(_.size) match {
-              case Some(batchSize) if batchSize > 25 =>
-                log.warning("received legacy batch of commit_sig exceeding our threshold ({} > 25), processing messages individually", batchSize)
-                // We don't want peers to be able to exhaust our memory by sending batches of dummy messages that we keep in RAM.
-                d.peer ! msg
-                stay()
-              case Some(batchSize) if batchSize > 1 =>
-                d.legacyCommitSigBatch_opt match {
-                  case Some(pending) if pending.channelId != msg.channelId || pending.batchSize != batchSize =>
-                    log.warning("received invalid commit_sig batch while a different batch isn't complete")
-                    // This should never happen, otherwise it will likely lead to a force-close.
-                    d.peer ! CommitSigBatch(pending.received)
-                    stay() using d.copy(legacyCommitSigBatch_opt = Some(PendingCommitSigBatch(msg.channelId, batchSize, Seq(msg))))
-                  case Some(pending) =>
-                    val received1 = pending.received :+ msg
-                    if (received1.size == batchSize) {
-                      log.debug("received last commit_sig in legacy batch for channel_id={}", msg.channelId)
-                      d.peer ! CommitSigBatch(received1)
-                      stay() using d.copy(legacyCommitSigBatch_opt = None)
-                    } else {
-                      log.debug("received commit_sig {}/{} in legacy batch for channel_id={}", received1.size, batchSize, msg.channelId)
-                      stay() using d.copy(legacyCommitSigBatch_opt = Some(pending.copy(received = received1)))
-                    }
-                  case None =>
-                    log.debug("received first commit_sig in legacy batch of size {} for channel_id={}", batchSize, msg.channelId)
-                    stay() using d.copy(legacyCommitSigBatch_opt = Some(PendingCommitSigBatch(msg.channelId, batchSize, Seq(msg))))
-                }
-              case _ =>
-                log.debug("received individual commit_sig for channel_id={}", msg.channelId)
-                d.peer ! msg
-                stay()
-            }
           case _ =>
             d.peer ! msg
             stay()
@@ -659,7 +624,6 @@ object PeerConnection {
                            behavior: Behavior = Behavior(),
                            expectedPong_opt: Option[ExpectedPong] = None,
                            commitSigBatch_opt: Option[PendingCommitSigBatch] = None,
-                           legacyCommitSigBatch_opt: Option[PendingCommitSigBatch] = None,
                            isPersistent: Boolean) extends Data with HasTransport
 
   case class PendingCommitSigBatch(channelId: ByteVector32, batchSize: Int, received: Seq[CommitSig])

eclair-core/src/main/scala/fr/acinq/eclair/wire/protocol/ChannelTlv.scala

@@ -258,14 +258,17 @@ object ChannelReestablishTlv {
   /**
    * When disconnected in the middle of an interactive-tx session, this field is used to request a retransmission of
    * [[TxSignatures]] for the given [[txId]].
+   *
+   * @param txId                the txid of the partially signed funding transaction.
+   * @param retransmitCommitSig true if [[CommitSig]] must be retransmitted before [[TxSignatures]].
    */
-  case class NextFundingTlv(txId: TxId) extends ChannelReestablishTlv
+  case class NextFundingTlv(txId: TxId, retransmitCommitSig: Boolean) extends ChannelReestablishTlv
 
-  /** The txid of the last [[ChannelReady]] or [[SpliceLocked]] message received before disconnecting, if any. */
-  case class YourLastFundingLockedTlv(txId: TxId) extends ChannelReestablishTlv
-
-  /** The txid of our latest outgoing [[ChannelReady]] or [[SpliceLocked]] for this channel. */
-  case class MyCurrentFundingLockedTlv(txId: TxId) extends ChannelReestablishTlv
+  /**
+   * @param txId              the txid of our latest outgoing [[ChannelReady]] or [[SpliceLocked]] for this channel.
+   * @param retransmitAnnSigs true if [[AnnouncementSignatures]] must be retransmitted.
+   */
+  case class MyCurrentFundingLockedTlv(txId: TxId, retransmitAnnSigs: Boolean) extends ChannelReestablishTlv
 
   /**
    * When disconnected during an interactive tx session, we'll include a verification nonce for our *current* commitment
@@ -281,15 +284,11 @@ object ChannelReestablishTlv {
   case class NextLocalNoncesTlv(nonces: Seq[(TxId, IndividualNonce)]) extends ChannelReestablishTlv
 
   object NextFundingTlv {
-    val codec: Codec[NextFundingTlv] = tlvField(txIdAsHash)
-  }
-
-  object YourLastFundingLockedTlv {
-    val codec: Codec[YourLastFundingLockedTlv] = tlvField("your_last_funding_locked_txid" | txIdAsHash)
+    val codec: Codec[NextFundingTlv] = tlvField(("next_funding_txid" | txIdAsHash) :: ("retransmit_flags" | (ignore(7) :: bool)))
   }
 
   object MyCurrentFundingLockedTlv {
-    val codec: Codec[MyCurrentFundingLockedTlv] = tlvField("my_current_funding_locked_txid" | txIdAsHash)
+    val codec: Codec[MyCurrentFundingLockedTlv] = tlvField(("my_current_funding_locked_txid" | txIdAsHash) :: ("retransmit_flags" | (ignore(7) :: bool)))
   }
 
   object CurrentCommitNonceTlv {
@@ -301,9 +300,8 @@ object ChannelReestablishTlv {
   }
 
   val channelReestablishTlvCodec: Codec[TlvStream[ChannelReestablishTlv]] = tlvStream(discriminated[ChannelReestablishTlv].by(varint)
-    .typecase(UInt64(0), NextFundingTlv.codec)
-    .typecase(UInt64(1), YourLastFundingLockedTlv.codec)
-    .typecase(UInt64(3), MyCurrentFundingLockedTlv.codec)
+    .typecase(UInt64(1), NextFundingTlv.codec)
+    .typecase(UInt64(5), MyCurrentFundingLockedTlv.codec)
     .typecase(UInt64(22), NextLocalNoncesTlv.codec)
     .typecase(UInt64(24), CurrentCommitNonceTlv.codec)
   )

eclair-core/src/main/scala/fr/acinq/eclair/wire/protocol/InteractiveTxTlv.scala

@@ -49,7 +49,7 @@ object TxAddInputTlv {
 
   val txAddInputTlvCodec: Codec[TlvStream[TxAddInputTlv]] = tlvStream(discriminated[TxAddInputTlv].by(varint)
     // Note that we actually encode as a tx_hash to be consistent with other lightning messages.
-    .typecase(UInt64(1105), tlvField(txIdAsHash.as[SharedInputTxId]))
+    .typecase(UInt64(0), tlvField(txIdAsHash.as[SharedInputTxId]))
     .typecase(UInt64(1111), PrevTxOut.codec)
   )
 }
@@ -103,8 +103,8 @@ object TxSignaturesTlv {
   case class PreviousFundingTxPartialSig(partialSigWithNonce: PartialSignatureWithNonce) extends TxSignaturesTlv
 
   val txSignaturesTlvCodec: Codec[TlvStream[TxSignaturesTlv]] = tlvStream(discriminated[TxSignaturesTlv].by(varint)
+    .typecase(UInt64(0), tlvField(bytes64.as[PreviousFundingTxSig]))
     .typecase(UInt64(2), tlvField(partialSignatureWithNonce.as[PreviousFundingTxPartialSig]))
-    .typecase(UInt64(601), tlvField(bytes64.as[PreviousFundingTxSig]))
   )
 }
 

eclair-core/src/main/scala/fr/acinq/eclair/wire/protocol/LightningMessageCodecs.scala

@@ -530,6 +530,9 @@ object LightningMessageCodecs {
     .typecase(72, txInitRbfCodec)
     .typecase(73, txAckRbfCodec)
     .typecase(74, txAbortCodec)
+    .typecase(77, spliceLockedCodec)
+    .typecase(80, spliceInitCodec)
+    .typecase(81, spliceAckCodec)
     .typecase(127, startBatchCodec)
     .typecase(128, updateAddHtlcCodec)
     .typecase(130, updateFulfillHtlcCodec)
@@ -562,9 +565,6 @@ object LightningMessageCodecs {
     .typecase(41045, addFeeCreditCodec)
     .typecase(41046, currentFeeCreditCodec)
     //
-    .typecase(37000, spliceInitCodec)
-    .typecase(37002, spliceAckCodec)
-    .typecase(37004, spliceLockedCodec)
     //
 
     //

eclair-core/src/main/scala/fr/acinq/eclair/wire/protocol/LightningMessageTypes.scala

@@ -212,8 +212,9 @@ case class ChannelReestablish(channelId: ByteVector32,
                               myCurrentPerCommitmentPoint: PublicKey,
                               tlvStream: TlvStream[ChannelReestablishTlv] = TlvStream.empty) extends ChannelMessage with HasChannelId {
   val nextFundingTxId_opt: Option[TxId] = tlvStream.get[ChannelReestablishTlv.NextFundingTlv].map(_.txId)
+  val retransmitInteractiveTxCommitSig: Boolean = tlvStream.get[ChannelReestablishTlv.NextFundingTlv].exists(_.retransmitCommitSig)
   val myCurrentFundingLocked_opt: Option[TxId] = tlvStream.get[ChannelReestablishTlv.MyCurrentFundingLockedTlv].map(_.txId)
-  val yourLastFundingLocked_opt: Option[TxId] = tlvStream.get[ChannelReestablishTlv.YourLastFundingLockedTlv].map(_.txId)
+  val retransmitAnnSigs: Boolean = tlvStream.get[ChannelReestablishTlv.MyCurrentFundingLockedTlv].exists(_.retransmitAnnSigs)
   val nextCommitNonces: Map[TxId, IndividualNonce] = tlvStream.get[ChannelReestablishTlv.NextLocalNoncesTlv].map(_.nonces.toMap).getOrElse(Map.empty)
   val currentCommitNonce_opt: Option[IndividualNonce] = tlvStream.get[ChannelReestablishTlv.CurrentCommitNonceTlv].map(_.nonce)
 }

eclair-core/src/test/resources/nonreg/codecs/050001-DATA_WAIT_FOR_FUNDING_CONFIRMED/fundee/data.json

@@ -14,7 +14,6 @@
         "initFeatures" : {
           "activated" : {
             "option_route_blinding" : "optional",
-            "splice_prototype" : "optional",
             "payment_secret" : "mandatory",
             "gossip_queries_ex" : "optional",
             "option_anchor_outputs" : "optional",
@@ -41,7 +40,6 @@
           "activated" : {
             "option_route_blinding" : "optional",
             "option_provide_storage" : "optional",
-            "splice_prototype" : "optional",
             "payment_secret" : "mandatory",
             "gossip_queries_ex" : "optional",
             "option_anchor_outputs" : "optional",

eclair-core/src/test/resources/nonreg/codecs/050001-DATA_WAIT_FOR_FUNDING_CONFIRMED/funder/data.json

@@ -15,7 +15,6 @@
           "activated" : {
             "option_route_blinding" : "optional",
             "option_provide_storage" : "optional",
-            "splice_prototype" : "optional",
             "payment_secret" : "mandatory",
             "gossip_queries_ex" : "optional",
             "option_anchor_outputs" : "optional",
@@ -41,7 +40,6 @@
         "initFeatures" : {
           "activated" : {
             "option_route_blinding" : "optional",
-            "splice_prototype" : "optional",
             "payment_secret" : "mandatory",
             "gossip_queries_ex" : "optional",
             "option_anchor_outputs" : "optional",

eclair-core/src/test/resources/nonreg/codecs/050002-DATA_WAIT_FOR_CHANNEL_READY/funder/data.json

@@ -15,7 +15,6 @@
           "activated" : {
             "option_route_blinding" : "optional",
             "option_provide_storage" : "optional",
-            "splice_prototype" : "optional",
             "payment_secret" : "mandatory",
             "gossip_queries_ex" : "optional",
             "option_anchor_outputs" : "optional",
@@ -41,7 +40,6 @@
         "initFeatures" : {
           "activated" : {
             "option_route_blinding" : "optional",
-            "splice_prototype" : "optional",
             "payment_secret" : "mandatory",
             "gossip_queries_ex" : "optional",
             "option_anchor_outputs" : "optional",

eclair-core/src/test/resources/nonreg/codecs/050003-DATA_WAIT_FOR_DUAL_FUNDING_SIGNED/fundee/data.json

@@ -13,7 +13,6 @@
         "activated" : {
           "option_route_blinding" : "optional",
           "option_dual_fund" : "optional",
-          "splice_prototype" : "optional",
           "payment_secret" : "mandatory",
           "gossip_queries_ex" : "optional",
           "option_anchor_outputs" : "optional",
@@ -40,7 +39,6 @@
           "option_route_blinding" : "optional",
           "option_provide_storage" : "optional",
           "option_dual_fund" : "optional",
-          "splice_prototype" : "optional",
           "payment_secret" : "mandatory",
           "gossip_queries_ex" : "optional",
           "option_anchor_outputs" : "optional",

eclair-core/src/test/resources/nonreg/codecs/050003-DATA_WAIT_FOR_DUAL_FUNDING_SIGNED/funder/data.json

@@ -14,7 +14,6 @@
           "option_route_blinding" : "optional",
           "option_provide_storage" : "optional",
           "option_dual_fund" : "optional",
-          "splice_prototype" : "optional",
           "payment_secret" : "mandatory",
           "gossip_queries_ex" : "optional",
           "option_anchor_outputs" : "optional",
@@ -40,7 +39,6 @@
         "activated" : {
           "option_route_blinding" : "optional",
           "option_dual_fund" : "optional",
-          "splice_prototype" : "optional",
           "payment_secret" : "mandatory",
           "gossip_queries_ex" : "optional",
           "option_anchor_outputs" : "optional",

eclair-core/src/test/resources/nonreg/codecs/050004-DATA_WAIT_FOR_DUAL_FUNDING_CONFIRMED/fundee/data.json

@@ -14,7 +14,6 @@
           "activated" : {
             "option_route_blinding" : "optional",
             "option_dual_fund" : "optional",
-            "splice_prototype" : "optional",
             "payment_secret" : "mandatory",
             "gossip_queries_ex" : "optional",
             "option_anchor_outputs" : "optional",
@@ -41,7 +40,6 @@
             "option_route_blinding" : "optional",
             "option_provide_storage" : "optional",
             "option_dual_fund" : "optional",
-            "splice_prototype" : "optional",
             "payment_secret" : "mandatory",
             "gossip_queries_ex" : "optional",
             "option_anchor_outputs" : "optional",

eclair-core/src/test/resources/nonreg/codecs/050004-DATA_WAIT_FOR_DUAL_FUNDING_CONFIRMED/funder/data.json

@@ -15,7 +15,6 @@
             "option_route_blinding" : "optional",
             "option_provide_storage" : "optional",
             "option_dual_fund" : "optional",
-            "splice_prototype" : "optional",
             "payment_secret" : "mandatory",
             "gossip_queries_ex" : "optional",
             "option_anchor_outputs" : "optional",
@@ -41,7 +40,6 @@
           "activated" : {
             "option_route_blinding" : "optional",
             "option_dual_fund" : "optional",
-            "splice_prototype" : "optional",
             "payment_secret" : "mandatory",
             "gossip_queries_ex" : "optional",
             "option_anchor_outputs" : "optional",