Cancel previous LiftChannelExclusion (#2510)

Keep at most one scheduled `LiftChannelExclusion` by cancelling the previous one if the new ban lasts longer

eclair-core/src/main/scala/fr/acinq/eclair/router/RouteCalculation.scala

@@ -99,7 +99,7 @@ object RouteCalculation {
       implicit val sender: ActorRef = ctx.self // necessary to preserve origin when sending messages to other actors
 
       val extraEdges = r.extraEdges.map(GraphEdge(_)).filterNot(_.desc.a == r.source).toSet // we ignore routing hints for our own channels, we have more accurate information
-      val ignoredEdges = r.ignore.channels ++ d.excludedChannels
+      val ignoredEdges = r.ignore.channels ++ d.excludedChannels.keySet
       val params = r.routeParams
       val routesToFind = if (params.randomize) DEFAULT_ROUTES_COUNT else 1
 

eclair-core/src/main/scala/fr/acinq/eclair/router/Router.scala

@@ -18,7 +18,7 @@ package fr.acinq.eclair.router
 
 import akka.Done
 import akka.actor.typed.scaladsl.adapter.actorRefAdapter
-import akka.actor.{Actor, ActorLogging, ActorRef, Props, Terminated, typed}
+import akka.actor.{Actor, ActorLogging, ActorRef, Cancellable, Props, Terminated, typed}
 import akka.event.DiagnosticLoggingAdapter
 import akka.event.Logging.MDC
 import fr.acinq.bitcoin.scalacompat.Crypto.PublicKey
@@ -109,7 +109,7 @@ class Router(val nodeParams: NodeParams, watcher: typed.ActorRef[ZmqWatcher.Comm
       awaiting = Map.empty,
       privateChannels = Map.empty,
       scid2PrivateChannels = Map.empty,
-      excludedChannels = Set.empty,
+      excludedChannels = Map.empty,
       graphWithBalances = GraphWithBalanceEstimates(graph, nodeParams.routerConf.balanceEstimateHalfLife),
       sync = Map.empty)
     startWith(NORMAL, data)
@@ -172,13 +172,34 @@ class Router(val nodeParams: NodeParams, watcher: typed.ActorRef[ZmqWatcher.Comm
 
     case Event(ExcludeChannel(desc, duration_opt), d) =>
       log.info("excluding shortChannelId={} from nodeId={} for duration={}", desc.shortChannelId, desc.a, duration_opt.getOrElse("n/a"))
-      duration_opt.foreach(banDuration => context.system.scheduler.scheduleOnce(banDuration, self, LiftChannelExclusion(desc)))
+      val (excludedUntil, oldTimer) = d.excludedChannels.get(desc) match {
-      stay() using d.copy(excludedChannels = d.excludedChannels + desc)
+        case Some(ExcludedForever) => (TimestampSecond.max, None)
+        case Some(ExcludedUntil(liftExclusionAt, timer)) => (liftExclusionAt, Some(timer))
+        case None => (TimestampSecond.min, None)
+      }
+      val newState = duration_opt match {
+        case Some(banDuration) =>
+          if (TimestampSecond.now() + banDuration > excludedUntil) {
+            oldTimer.foreach(_.cancel())
+            val newTimer = context.system.scheduler.scheduleOnce(banDuration, self, LiftChannelExclusion(desc))
+            ExcludedUntil(TimestampSecond.now() + banDuration, newTimer)
+          } else {
+            d.excludedChannels(desc)
+          }
+        case None =>
+          oldTimer.foreach(_.cancel())
+          ExcludedForever
+      }
+      stay() using d.copy(excludedChannels = d.excludedChannels + (desc -> newState))
 
     case Event(LiftChannelExclusion(desc@ChannelDesc(shortChannelId, nodeId, _)), d) =>
       log.info("reinstating shortChannelId={} from nodeId={}", shortChannelId, nodeId)
       stay() using d.copy(excludedChannels = d.excludedChannels - desc)
 
+    case Event(GetExcludedChannels, d) =>
+      sender() ! d.excludedChannels
+      stay()
+
     case Event(GetNodes, d) =>
       sender() ! d.nodes.values
       stay()
@@ -579,6 +600,12 @@ object Router {
   /** This is used when we get a TemporaryChannelFailure, to give time for the channel to recover (note that exclusions are directed) */
   case class ExcludeChannel(desc: ChannelDesc, duration_opt: Option[FiniteDuration])
   case class LiftChannelExclusion(desc: ChannelDesc)
+
+  sealed trait ExcludedChannelStatus
+  case object ExcludedForever extends ExcludedChannelStatus
+  case class ExcludedUntil(liftExclusionAt: TimestampSecond, timer: Cancellable) extends ExcludedChannelStatus
+
+  case object GetExcludedChannels
   // @formatter:on
 
   // @formatter:off
@@ -643,7 +670,7 @@ object Router {
                   awaiting: Map[ChannelAnnouncement, Seq[GossipOrigin]], // note: this is a seq because we want to preserve order: first actor is the one who we need to send a tcp-ack when validation is done
                   privateChannels: Map[ByteVector32, PrivateChannel], // indexed by channel id
                   scid2PrivateChannels: Map[Long, ByteVector32], // real scid or alias to channel_id, only to be used for private channels
-                  excludedChannels: Set[ChannelDesc], // those channels are temporarily excluded from route calculation, because their node returned a TemporaryChannelFailure
+                  excludedChannels: Map[ChannelDesc, ExcludedChannelStatus], // those channels are temporarily excluded from route calculation, because their node returned a TemporaryChannelFailure
                   graphWithBalances: GraphWithBalanceEstimates,
                   sync: Map[PublicKey, Syncing] // keep tracks of channel range queries sent to each peer. If there is an entry in the map, it means that there is an ongoing query for which we have not yet received an 'end' message
                  ) {

eclair-core/src/test/scala/fr/acinq/eclair/router/RouterSpec.scala

@@ -504,6 +504,32 @@ class RouterSpec extends BaseRouterSpec {
     sender.expectMsgType[RouteResponse]
   }
 
+  test("concurrent channel exclusions") { fixture =>
+    import fixture._
+    val sender = TestProbe()
+    sender.send(router, RouteRequest(a, d, DEFAULT_AMOUNT_MSAT, DEFAULT_MAX_FEE, routeParams = DEFAULT_ROUTE_PARAMS))
+    sender.expectMsgType[RouteResponse]
+    val bc = ChannelDesc(scid_bc, b, c)
+    sender.send(router, ExcludeChannel(bc, Some(1 second)))
+    sender.send(router, ExcludeChannel(bc, Some(10 minute)))
+    sender.send(router, ExcludeChannel(bc, Some(1 second)))
+    sender.send(router, RouteRequest(a, d, DEFAULT_AMOUNT_MSAT, DEFAULT_MAX_FEE, routeParams = DEFAULT_ROUTE_PARAMS))
+    sender.expectMsg(Failure(RouteNotFound))
+    sender.send(router, GetExcludedChannels)
+    val excludedChannels1 = sender.expectMsgType[Map[ChannelDesc, ExcludedChannelStatus]]
+    assert(excludedChannels1.size == 1)
+    assert(excludedChannels1(bc).isInstanceOf[ExcludedUntil])
+    assert(excludedChannels1(bc).asInstanceOf[ExcludedUntil].liftExclusionAt > TimestampSecond.now() + 9.minute)
+    sender.send(router, LiftChannelExclusion(bc))
+    sender.send(router, RouteRequest(a, d, DEFAULT_AMOUNT_MSAT, DEFAULT_MAX_FEE, routeParams = DEFAULT_ROUTE_PARAMS))
+    sender.expectMsgType[RouteResponse]
+    sender.send(router, ExcludeChannel(bc, None))
+    sender.send(router, GetExcludedChannels)
+    val excludedChannels2 = sender.expectMsgType[Map[ChannelDesc, ExcludedChannelStatus]]
+    assert(excludedChannels2.size == 1)
+    assert(excludedChannels2(bc) == ExcludedForever)
+  }
+
   test("send routing state") { fixture =>
     import fixture._
     val sender = TestProbe()