EstablishedPeers: Fixed an issue with unreachable peers when trying to promote other peers

Author: the-headless-ghost

ouroboros-network/src/Ouroboros/Network/PeerSelection/Governor/EstablishedPeers.hs

@@ -96,7 +96,7 @@ belowTarget
 belowTarget enableAction inboundPeers =
      belowTargetBigLedgerPeers enableAction
   <> belowTargetLocal inboundPeers
-  <> belowTargetOther
+  <> belowTargetOther inboundPeers
 
 
 -- | For locally configured root peers we have the explicit target that comes from local
@@ -200,6 +200,7 @@ belowTargetLocal inboundPeers
   , let potentialToPromote =
           -- These are local peers that are cold but not ready.
           localRootPeersSet
+             Set.\\ unreachablePeers
              Set.\\ localEstablishedPeers
              Set.\\ KnownPeers.availableToConnect knownPeers
   , not (Set.null potentialToPromote)
@@ -239,7 +240,9 @@ belowTargetOther
      , Ord peeraddr
      , HasCallStack
      )
-  => PeerSelectionActions
+  => Map peeraddr PeerSharing
+  -- ^ Inbound peers that have negotiated a duplex connection
+  -> PeerSelectionActions
       extraState
       extraFlags
       extraPeers
@@ -256,7 +259,7 @@ belowTargetOther
       peeraddr
       peerconn
       m
-belowTargetOther actions@PeerSelectionActions {
+belowTargetOther inboundPeers actions@PeerSelectionActions {
                    extraPeersAPI = PublicExtraPeersAPI {
                      memberExtraPeers,
                      extraPeersToSet
@@ -283,7 +286,7 @@ belowTargetOther actions@PeerSelectionActions {
     -- not cold and our invariant is that they are always in the connect set.
     -- We can also subtract the in progress ones since they are also already
     -- in the connect set and we cannot pick them again.
-  , numAvailableToConnect - numFollowBackPeers - numEstablishedPeers - numConnectInProgress > 0
+  , numAvailableToConnect - numUnreachablePeers - numEstablishedPeers - numConnectInProgress > 0
   = Guarded Nothing $ do
       -- The availableToPromote here is non-empty due to the second guard.
       -- The known peers map restricted to the connect set is the same size as
@@ -295,7 +298,7 @@ belowTargetOther actions@PeerSelectionActions {
       --
       let availableToPromote :: Set peeraddr
           availableToPromote = availableToConnect
-                                 Set.\\ followBackPeers
+                                 Set.\\ unreachablePeers
                                  Set.\\ EstablishedPeers.toSet establishedPeers
                                  Set.\\ inProgressPromoteCold
           numPeersToPromote  = targetNumberOfEstablishedPeers
@@ -327,11 +330,15 @@ belowTargetOther actions@PeerSelectionActions {
   | otherwise
   = GuardedSkip Nothing
   where
-    numFollowBackPeers = Set.size followBackPeers
+    numUnreachablePeers = Set.size unreachablePeers
 
-    followBackPeers    = Map.keysSet
-      $ Map.filter (\(LocalRootConfig {followBack}) -> followBack)
-      $ LocalRootPeers.toMap localRootPeers
+    isUnreachablePeer addr (LocalRootConfig {followBack}) =
+      followBack && not (Map.member addr inboundPeers)
+
+    unreachablePeers =
+      Map.keysSet
+        $ Map.filterWithKey isUnreachablePeer
+        $ LocalRootPeers.toMap localRootPeers
 
     PeerSelectionView {
         viewKnownBigLedgerPeers     = (bigLedgerPeersSet, _),