small changes

- change default parameters and explain them better
- remove checks on incomming HTLCs

Author: thomash-acinq

docs/release-notes/eclair-vnext.md

@@ -37,7 +37,7 @@ To configure, edit `eclair.conf`:
 ```eclair.conf
 // We assign reputations to our peers to prioritize payments during congestion.
 // The reputation is computed as fees paid divided by what should have been paid if all payments were successful.
-eclair.peer-reputation {
+eclair.relay.peer-reputation {
     // Set this parameter to false to disable the reputation algorithm and simply relay the incoming endorsement
     // value, as described by https://github.com/lightning/blips/blob/master/blip-0004.md,
     enabled = true

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

@@ -245,12 +245,14 @@ eclair {
       // value, as described by https://github.com/lightning/blips/blob/master/blip-0004.md,
       enabled = true
       // Reputation decays with the following half life to emphasize recent behavior.
-      half-life = 7 days
+      half-life = 15 days
       // Payments that stay pending for longer than this get penalized.
       max-relay-duration = 12 seconds
       // Pending payments are counted as failed, and because they could potentially stay pending for a very long time,
-      // the following multiplier is applied.
-      pending-multiplier = 1000 // A pending payment counts as a thousand failed ones.
+      // the following multiplier is applied. We want it to be as close as possible to the true cost of a worst case
+      // HTLC (max-cltv-delta / max-relay-duration, around 100000 with default parameters) while still being comparable
+      // to the number of HTLCs received per peer during twice the half life.
+      pending-multiplier = 200 // A pending payment counts as two hundred failed ones.
     }
   }
 

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

@@ -565,14 +565,6 @@ case class Commitment(fundingTxIndex: Long,
       return Left(TooManyAcceptedHtlcs(params.channelId, maximum = params.localParams.maxAcceptedHtlcs))
     }
 
-    // Jamming protection
-    // Must be the last checks so that they can be ignored for shadow deployment.
-    for ((amountMsat, i) <- incomingHtlcs.toSeq.map(_.amountMsat).sorted.zipWithIndex) {
-      if ((amountMsat.toLong < 1) || (math.log(amountMsat.toLong.toDouble) * params.localParams.maxAcceptedHtlcs / math.log(params.localParams.maxHtlcValueInFlightMsat.toLong.toDouble / params.localParams.maxAcceptedHtlcs) < i)) {
-        return Left(TooManySmallHtlcs(params.channelId, number = i + 1, below = amountMsat))
-      }
-    }
-
     Right(())
   }
 
@@ -901,7 +893,7 @@ case class Commitments(params: ChannelParams,
       .getOrElse(Right(copy(changes = changes1, originChannels = originChannels1), add))
   }
 
-  def receiveAdd(add: UpdateAddHtlc, feerates: FeeratesPerKw, feeConf: OnChainFeeConf)(implicit log: LoggingAdapter): Either[ChannelException, Commitments] = {
+  def receiveAdd(add: UpdateAddHtlc, feerates: FeeratesPerKw, feeConf: OnChainFeeConf): Either[ChannelException, Commitments] = {
     if (add.id != changes.remoteNextHtlcId) {
       return Left(UnexpectedHtlcId(channelId, expected = changes.remoteNextHtlcId, actual = add.id))
     }
@@ -914,21 +906,8 @@ case class Commitments(params: ChannelParams,
 
     val changes1 = changes.addRemoteProposal(add).copy(remoteNextHtlcId = changes.remoteNextHtlcId + 1)
     // we verify that this htlc is allowed in every active commitment
-    val canReceiveAdds = active.map(_.canReceiveAdd(add.amountMsat, params, changes1, feerates, feeConf))
-    // Log only for jamming protection.
-    canReceiveAdds.collectFirst {
-      case Left(f: TooManySmallHtlcs) =>
-        log.info("TooManySmallHtlcs: {} incoming HTLCs are below {}}", f.number, f.below)
-        Metrics.dropHtlc(f, Tags.Directions.Incoming)
-    }
-    canReceiveAdds.flatMap { // TODO: We ignore jamming protection, delete this flatMap to activate jamming protection.
-        case Left(_: TooManySmallHtlcs) | Left(_: ConfidenceTooLow) => None
-        case x => Some(x)
-      }
-      .collectFirst { case Left(f) =>
-        Metrics.dropHtlc(f, Tags.Directions.Incoming)
-        Left(f)
-      }
+    active.map(_.canReceiveAdd(add.amountMsat, params, changes1, feerates, feeConf))
+      .collectFirst { case Left(f) => Left(f) }
       .getOrElse(Right(copy(changes = changes1)))
   }