Compute channel keys only once on startup

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

@@ -34,15 +34,13 @@ object DBChecker extends Logging {
   def checkChannelsDB(nodeParams: NodeParams): Seq[PersistentChannelData] = {
     Try(nodeParams.db.channels.listLocalChannels()) match {
       case Success(channels) =>
-        channels.foreach {
+        channels.collect {
           case data: ChannelDataWithCommitments =>
             val channelKeys = nodeParams.channelKeyManager.channelKeys(data.channelParams.channelConfig, data.channelParams.localParams.fundingKeyPath)
-            if (!data.commitments.validateSeed(channelKeys)) {
-              throw InvalidChannelSeedException(data.channelId)
-            }
-          case _ => ()
+            data.setChannelKeys(channelKeys)
+            data
+          case data => data
         }
-        channels
       case Failure(t) => throw IncompatibleDBException(t)
     }
   }

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

@@ -23,12 +23,13 @@ import fr.acinq.eclair.blockchain.fee.{ConfirmationTarget, FeeratePerKw}
 import fr.acinq.eclair.channel.Helpers.Closing
 import fr.acinq.eclair.channel.fund.InteractiveTxBuilder._
 import fr.acinq.eclair.channel.fund.{InteractiveTxBuilder, InteractiveTxSigningSession}
+import fr.acinq.eclair.crypto.keymanager.ChannelKeys
 import fr.acinq.eclair.io.Peer
 import fr.acinq.eclair.reputation.Reputation
 import fr.acinq.eclair.transactions.CommitmentSpec
 import fr.acinq.eclair.transactions.Transactions._
 import fr.acinq.eclair.wire.protocol.{ChannelAnnouncement, ChannelReady, ChannelReestablish, ChannelUpdate, ClosingSigned, CommitSig, FailureReason, FundingCreated, FundingSigned, Init, LiquidityAds, OnionRoutingPacket, OpenChannel, OpenDualFundedChannel, Shutdown, SpliceInit, Stfu, TxInitRbf, TxSignatures, UpdateAddHtlc, UpdateFailHtlc, UpdateFailMalformedHtlc, UpdateFulfillHtlc}
-import fr.acinq.eclair.{Alias, BlockHeight, CltvExpiry, CltvExpiryDelta, Features, InitFeature, MilliSatoshi, MilliSatoshiLong, RealShortChannelId, TimestampMilli, UInt64}
+import fr.acinq.eclair.{Alias, BlockHeight, CltvExpiry, CltvExpiryDelta, Features, InitFeature, InvalidChannelSeedException, MilliSatoshi, MilliSatoshiLong, RealShortChannelId, TimestampMilli, UInt64}
 import scodec.bits.ByteVector
 
 import java.util.UUID
@@ -549,17 +550,30 @@ case object Nothing extends TransientChannelData {
 sealed trait PersistentChannelData extends ChannelData {
   def remoteNodeId: PublicKey
   def channelParams: ChannelParams
+  // channel keys are never persisted or serialized
+  @transient private var channelKeys_opt: Option[ChannelKeys] = None
+  def validateChannelKeys(channelKeys: ChannelKeys): Boolean
+  def setChannelKeys(channelKeys: ChannelKeys): Unit = {
+    if (!validateChannelKeys(channelKeys)) {
+      throw InvalidChannelSeedException(channelId)
+    }
+    channelKeys_opt = Some(channelKeys)
+  }
+  def getChannelKeys: Option[ChannelKeys] = channelKeys_opt
 }
 sealed trait ChannelDataWithoutCommitments extends PersistentChannelData {
   val channelId: ByteVector32 = channelParams.channelId
   val remoteNodeId: PublicKey = channelParams.remoteNodeId
   def channelParams: ChannelParams
+  override def validateChannelKeys(channelKeys:  ChannelKeys): Boolean = true
 }
+
 sealed trait ChannelDataWithCommitments extends PersistentChannelData {
   val channelId: ByteVector32 = commitments.channelId
   val remoteNodeId: PublicKey = commitments.remoteNodeId
   val channelParams: ChannelParams = commitments.channelParams
   def commitments: Commitments
+  override def validateChannelKeys(channelKeys:  ChannelKeys): Boolean = commitments.validateSeed(channelKeys)
 }
 
 sealed trait ClosedData extends ChannelData

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

@@ -83,7 +83,7 @@ class Peer(val nodeParams: NodeParams,
     case Event(init: Init, _) =>
       pendingOnTheFlyFunding = init.pendingOnTheFlyFunding
       val channels = init.storedChannels.map { state =>
-        val channelKeys = nodeParams.channelKeyManager.channelKeys(state.channelParams.channelConfig, state.channelParams.localParams.fundingKeyPath)
+        val channelKeys = state.getChannelKeys.getOrElse(nodeParams.channelKeyManager.channelKeys(state.channelParams.channelConfig, state.channelParams.localParams.fundingKeyPath))
         val channel = spawnChannel(channelKeys)
         channel ! INPUT_RESTORED(state)
         FinalChannelId(state.channelId) -> channel

eclair-core/src/main/scala/fr/acinq/eclair/payment/relay/PostRestartHtlcCleaner.scala

@@ -429,7 +429,7 @@ object PostRestartHtlcCleaner {
               case Some(_: Closing.MutualClose) => Set.empty
               case None => Set.empty
             }
-            val channelKeys = nodeParams.channelKeyManager.channelKeys(d.commitments.channelParams.channelConfig, d.commitments.localChannelParams.fundingKeyPath)
+            val channelKeys = d.getChannelKeys.getOrElse(nodeParams.channelKeyManager.channelKeys(d.commitments.channelParams.channelConfig, d.commitments.localChannelParams.fundingKeyPath))
             val timedOutHtlcs: Set[Long] = (closingType_opt match {
               case Some(c: Closing.LocalClose) => confirmedTxs.flatMap(tx => Closing.trimmedOrTimedOutHtlcs(channelKeys, d.commitments.latest, c.localCommit, tx))
               case Some(c: Closing.RemoteClose) => confirmedTxs.flatMap(tx => Closing.trimmedOrTimedOutHtlcs(channelKeys, d.commitments.latest, c.remoteCommit, tx))