Add rlpx metrics and avoid immediate peer reconnections (#585)

* Add metrics related to devp2p peer connections

* Avoid reconnecting to peers that just failed connection

- Add SeenTable to avoid reconnecting to peers immediately after
a failed connect. Depending on the failure, the amount of time is
different. This is similar to what is done in nimbus-eth2.
- Attempt to rework rlpxConnect at the same time, in order to
make sure that errors are properly handled. The current structure
is far from ideal, but it is hopefully a small step in the right
direction. To many oddities in there right now to really rework
rlpxConnect properply.

* Fix rlpx thunk fuzzer

eth/p2p/kademlia.nim

@@ -9,12 +9,15 @@
 
 import
   std/[tables, hashes, times, algorithm, sets, sequtils],
-  chronos, chronicles, stint, nimcrypto/keccak,
+  chronos, chronicles, stint, nimcrypto/keccak, metrics,
   ../keys, ./discoveryv5/random2,
   ./enode
 
 export sets # TODO: This should not be needed, but compilation fails otherwise
 
+declarePublicGauge routing_table_nodes,
+  "Discovery routing table nodes"
+
 logScope:
   topics = "eth p2p kademlia"
 
@@ -215,6 +218,7 @@ proc add(k: KBucket, n: Node): Node =
       k.nodes.add(n)
   elif k.len < BUCKET_SIZE:
       k.nodes.add(n)
+      routing_table_nodes.inc()
   else:
       k.replacementCache.add(n)
       return k.head
@@ -222,7 +226,9 @@ proc add(k: KBucket, n: Node): Node =
 
 proc removeNode(k: KBucket, n: Node) =
   let i = k.nodes.find(n)
-  if i != -1: k.nodes.delete(i)
+  if i != -1:
+    routing_table_nodes.dec()
+    k.nodes.delete(i)
 
 proc split(k: KBucket): tuple[lower, upper: KBucket] =
   ## Split at the median id

eth/p2p/peer_pool.nim

@@ -26,6 +26,42 @@ const
   maxConcurrentConnectionRequests = 40
   sleepBeforeTryingARandomBootnode = chronos.milliseconds(3000)
 
+  ## Period of time for dead / unreachable peers.
+  SeenTableTimeDeadPeer = chronos.minutes(10)
+  ## Period of time for Useless peers, either because of no matching
+  ## capabilities or on an irrelevant network.
+  SeenTableTimeUselessPeer = chronos.hours(24)
+  ## Period of time for peers with a protocol error.
+  SeenTableTimeProtocolError = chronos.minutes(30)
+  ## Period of time for peers with general disconnections / transport errors.
+  SeenTableTimeReconnect = chronos.minutes(5)
+
+proc isSeen(p: PeerPool, nodeId: NodeId): bool =
+  ## Returns ``true`` if ``nodeId`` present in SeenTable and time period is not
+  ## yet expired.
+  let currentTime = now(chronos.Moment)
+  if nodeId notin p.seenTable:
+    false
+  else:
+    let item = try: p.seenTable[nodeId]
+    except KeyError: raiseAssert "checked with notin"
+    if currentTime >= item.stamp:
+      # Peer is in SeenTable, but the time period has expired.
+      p.seenTable.del(nodeId)
+      false
+    else:
+      true
+
+proc addSeen(
+    p: PeerPool, nodeId: NodeId, period: chronos.Duration) =
+  ## Adds peer with NodeId ``nodeId`` to SeenTable and timeout ``period``.
+  let item = SeenNode(nodeId: nodeId, stamp: now(chronos.Moment) + period)
+  withValue(p.seenTable, nodeId, entry) do:
+    if entry.stamp < item.stamp:
+      entry.stamp = item.stamp
+  do:
+    p.seenTable[nodeId] = item
+
 proc newPeerPool*(
     network: EthereumNode, networkId: NetworkId, keyPair: KeyPair,
     discovery: DiscoveryProtocol, clientId: string, minPeers = 10): PeerPool =
@@ -84,28 +120,36 @@ proc connect(p: PeerPool, remote: Node): Future[Peer] {.async.} =
     # debug "skipping connection"
     return nil
 
+  if p.isSeen(remote.id):
+    return nil
+
   trace "Connecting to node", remote
   p.connectingNodes.incl(remote)
-  result = await p.network.rlpxConnect(remote)
+  let res = await p.network.rlpxConnect(remote)
   p.connectingNodes.excl(remote)
 
-  # expected_exceptions = (
+  # TODO: Probably should move all this logic to rlpx.nim
-  #   UnreachablePeer, TimeoutError, PeerConnectionLost, HandshakeFailure)
+  if res.isOk():
-  # try:
+    rlpx_connect_success.inc()
-  #   self.logger.debug("Connecting to %s...", remote)
+    return res.get()
-  #   peer = await wait_with_token(
+  else:
-  #     handshake(remote, self.privkey, self.peer_class, self.network_id),
+    rlpx_connect_failure.inc()
-  #     token=self.cancel_token,
+    rlpx_connect_failure.inc(labelValues = [$res.error])
-  #     timeout=HANDSHAKE_TIMEOUT)
+    case res.error():
-  #   return peer
+    of UselessRlpxPeerError:
-  # except OperationCancelled:
+      p.addSeen(remote.id, SeenTableTimeUselessPeer)
-  #   # Pass it on to instruct our main loop to stop.
+    of TransportConnectError:
-  #   raise
+      p.addSeen(remote.id, SeenTableTimeDeadPeer)
-  # except expected_exceptions as e:
+    of RlpxHandshakeError, ProtocolError, InvalidIdentityError:
-  #   self.logger.debug("Could not complete handshake with %s: %s", remote, repr(e))
+      p.addSeen(remote.id, SeenTableTimeProtocolError)
-  # except Exception:
+    of RlpxHandshakeTransportError,
-  #   self.logger.exception("Unexpected error during auth/p2p handshake with %s", remote)
+        P2PHandshakeError,
-  # return None
+        P2PTransportError,
+        PeerDisconnectedError,
+        TooManyPeersError:
+      p.addSeen(remote.id, SeenTableTimeReconnect)
+
+    return nil
 
 proc lookupRandomNode(p: PeerPool) {.async.} =
   discard await p.discovery.lookupRandom()
@@ -118,7 +162,7 @@ proc getRandomBootnode(p: PeerPool): Option[Node] =
 proc addPeer*(pool: PeerPool, peer: Peer) {.gcsafe.} =
   doAssert(peer.remote notin pool.connectedNodes)
   pool.connectedNodes[peer.remote] = peer
-  connected_peers.inc()
+  rlpx_connected_peers.inc()
   for o in pool.observers.values:
     if not o.onPeerConnected.isNil:
       if o.protocol.isNil or peer.supports(o.protocol):

eth/p2p/private/p2p_types.nim

@@ -53,6 +53,10 @@ type
     when useSnappy:
       snappyEnabled*: bool
 
+  SeenNode* = object
+    nodeId*: NodeId
+    stamp*: chronos.Moment
+
   PeerPool* = ref object
     # Private fields:
     network*: EthereumNode
@@ -63,6 +67,7 @@ type
     discovery*: DiscoveryProtocol
     lastLookupTime*: float
     connQueue*: AsyncQueue[Node]
+    seenTable*: Table[NodeId, SeenNode]
     connectedNodes*: Table[Node, Peer]
     connectingNodes*: HashSet[Node]
     running*: bool

eth/p2p/rlpx.nim

@@ -8,8 +8,8 @@
 {.push raises: [Defect].}
 
 import
-  std/[tables, algorithm, deques, hashes, options, typetraits],
+  std/[tables, algorithm, deques, hashes, options, typetraits, os],
-  stew/shims/macros, chronicles, nimcrypto/utils, chronos,
+  stew/shims/macros, chronicles, nimcrypto/utils, chronos, metrics,
   ".."/[rlp, common, keys, async_utils],
   ./private/p2p_types, "."/[kademlia, auth, rlpxcrypt, enode, p2p_protocol_dsl]
 
@@ -24,6 +24,9 @@ const
   # github.com/ethereum/devp2p/blob/master/rlpx.md#framing
   allowObsoletedChunkedMessages = defined(chunked_rlpx_enabled)
 
+# TODO: This doesn't get enabled currently in any of the builds, so we send a
+# devp2p protocol handshake message with version. Need to check if some peers
+# drop us because of this.
 when useSnappy:
   import snappy
   const devp2pSnappyVersion* = 5
@@ -34,7 +37,20 @@ when useSnappy:
 export
   options, p2pProtocol, rlp, chronicles
 
-declarePublicGauge connected_peers, "number of peers in the pool"
+declarePublicGauge rlpx_connected_peers,
+  "Number of connected peers in the pool"
+
+declarePublicCounter rlpx_connect_success,
+  "Number of successfull rlpx connects"
+
+declarePublicCounter rlpx_connect_failure,
+  "Number of rlpx connects that failed", labels = ["reason"]
+
+declarePublicCounter rlpx_accept_success,
+  "Number of successful rlpx accepted peers"
+
+declarePublicCounter rlpx_accept_failure,
+  "Number of rlpx accept attempts that failed", labels = ["reason"]
 
 logScope:
   topics = "eth p2p rlpx"
@@ -185,6 +201,10 @@ proc handshakeImpl[T](peer: Peer,
   doAssert timeout.milliseconds > 0
   yield responseFut or sleepAsync(timeout)
   if not responseFut.finished:
+    # TODO: Really shouldn't disconnect and raise everywhere. In order to avoid
+    # understanding what error occured where.
+    # And also, incoming and outgoing disconnect errors should be seperated,
+    # probably by seperating the actual disconnect call to begin with.
     await disconnectAndRaise(peer, HandshakeTimeout,
                              "Protocol handshake was not received in time.")
   elif responseFut.failed:
@@ -708,6 +728,7 @@ proc waitSingleMsg(peer: Peer, MsgType: type): Future[MsgType] {.async.} =
                                       "Invalid RLPx message body")
 
     elif nextMsgId == 1: # p2p.disconnect
+      # TODO: can still raise RlpError here...?
       let reasonList = nextMsgData.read(DisconnectionReasonList)
       let reason = reasonList.value
       await peer.disconnect(reason)
@@ -716,6 +737,7 @@ proc waitSingleMsg(peer: Peer, MsgType: type): Future[MsgType] {.async.} =
     else:
       warn "Dropped RLPX message",
            msg = peer.dispatcher.messages[nextMsgId].name
+      # TODO: This is breach of protocol?
 
 proc nextMsg*(peer: Peer, MsgType: type): Future[MsgType] =
   ## This procs awaits a specific RLPx message.
@@ -1048,7 +1070,7 @@ proc removePeer(network: EthereumNode, peer: Peer) =
   if network.peerPool != nil and not peer.remote.isNil and
       peer.remote in network.peerPool.connectedNodes:
     network.peerPool.connectedNodes.del(peer.remote)
-    connected_peers.dec()
+    rlpx_connected_peers.dec()
 
     # Note: we need to do this check as disconnect (and thus removePeer)
     # currently can get called before the dispatcher is initialized.
@@ -1104,11 +1126,11 @@ proc disconnect*(peer: Peer, reason: DisconnectionReason,
     peer.connectionState = Disconnected
     removePeer(peer.network, peer)
 
-proc validatePubKeyInHello(msg: DevP2P.hello, pubKey: PublicKey): bool =
+func validatePubKeyInHello(msg: DevP2P.hello, pubKey: PublicKey): bool =
   let pk = PublicKey.fromRaw(msg.nodeId)
   pk.isOk and pk[] == pubKey
 
-proc checkUselessPeer(peer: Peer) {.raises: [UselessPeerError, Defect].} =
+func checkUselessPeer(peer: Peer) {.raises: [UselessPeerError, Defect].} =
   if peer.dispatcher.numProtocols == 0:
     # XXX: Send disconnect + UselessPeer
     raise newException(UselessPeerError, "Useless peer")
@@ -1183,13 +1205,12 @@ template `^`(arr): auto =
   # variable as an open array
   arr.toOpenArray(0, `arr Len` - 1)
 
-proc initSecretState(hs: var Handshake, authMsg, ackMsg: openArray[byte],
+proc initSecretState(p: Peer, hs: Handshake, authMsg, ackMsg: openArray[byte]) =
-    p: Peer) =
   var secrets = hs.getSecrets(authMsg, ackMsg)
   initSecretState(secrets, p.secretsState)
   burnMem(secrets)
 
-template checkSnappySupport(node: EthereumNode, handshake: Handshake, peer: Peer) =
+template setSnappySupport(peer: Peer, node: EthereumNode, handshake: Handshake) =
   when useSnappy:
     peer.snappyEnabled = node.protocolVersion >= devp2pSnappyVersion.uint and
                          handshake.version >= devp2pSnappyVersion.uint
@@ -1213,106 +1234,170 @@ template baseProtocolVersion(peer: Peer): uint =
   else:
     devp2pVersion
 
-proc rlpxConnect*(node: EthereumNode, remote: Node): Future[Peer] {.async.} =
+type
+  RlpxError* = enum
+    TransportConnectError,
+    RlpxHandshakeTransportError,
+    RlpxHandshakeError,
+    ProtocolError,
+    P2PHandshakeError,
+    P2PTransportError,
+    InvalidIdentityError,
+    UselessRlpxPeerError,
+    PeerDisconnectedError,
+    TooManyPeersError
+
+proc rlpxConnect*(node: EthereumNode, remote: Node):
+    Future[Result[Peer, RlpxError]] {.async.} =
+  # TODO: Should we not set some timeouts on the `connect` and `readExactly`s?
+  # Or should we have a general timeout on the whole rlpxConnect where it gets
+  # called?
+  # Now, some parts could potential hang until a tcp timeout is hit?
   initTracing(devp2pInfo, node.protocols)
 
   let peer = Peer(remote: remote, network: node)
   let ta = initTAddress(remote.node.address.ip, remote.node.address.tcpPort)
-  var ok = false
+  var error = true
-  try:
-    peer.transport = await connect(ta)
-    var handshake = Handshake.init(
-      node.rng[], node.keys, {Initiator, EIP8}, node.baseProtocolVersion)
 
-    var authMsg: array[AuthMessageMaxEIP8, byte]
+  defer:
-    var authMsgLen = 0
+    if error: # TODO: Not sure if I like this much
+      if not isNil(peer.transport):
+        if not peer.transport.closed:
+          peer.transport.close()
+
+  peer.transport =
+    try:
+      await connect(ta)
+    except TransportError:
+      return err(TransportConnectError)
+    except CatchableError as e:
+      # Aside from TransportOsError, seems raw CatchableError can also occur?
+      debug "TCP connect with peer failed", err = $e.name, errMsg = $e.msg
+      return err(TransportConnectError)
+
+  # RLPx initial handshake
+  var
+    handshake = Handshake.init(
+      node.rng[], node.keys, {Initiator, EIP8}, node.baseProtocolVersion)
+    authMsg: array[AuthMessageMaxEIP8, byte]
+    authMsgLen = 0
+  # TODO: Rework this so we won't have to pass an array as parameter?
   authMessage(
     handshake, node.rng[], remote.node.pubkey, authMsg, authMsgLen).tryGet()
-    var res = await peer.transport.write(addr authMsg[0], authMsgLen)
+
-    if res != authMsgLen:
+  let writeRes =
-      raisePeerDisconnected("Unexpected disconnect while authenticating",
+    try:
-                            TcpError)
+      await peer.transport.write(addr authMsg[0], authMsgLen)
+    except TransportError:
+      return err(RlpxHandshakeTransportError)
+    except CatchableError as e: # TODO: Only TransportErrors can occur?
+      raiseAssert($e.name & " " & $e.msg)
+  if writeRes != authMsgLen:
+    return err(RlpxHandshakeTransportError)
 
   let initialSize = handshake.expectedLength
   var ackMsg = newSeqOfCap[byte](1024)
   ackMsg.setLen(initialSize)
 
-    # TODO: Should we not set some timeouts on these `readExactly`s?
+  try:
     await peer.transport.readExactly(addr ackMsg[0], len(ackMsg))
+  except TransportError:
+    return err(RlpxHandshakeTransportError)
+  except CatchableError as e:
+    raiseAssert($e.name & " " & $e.msg)
 
-    var ret = handshake.decodeAckMessage(ackMsg)
+  let res = handshake.decodeAckMessage(ackMsg)
-    if ret.isErr and ret.error == AuthError.IncompleteError:
+  if res.isErr and res.error == AuthError.IncompleteError:
     ackMsg.setLen(handshake.expectedLength)
+    try:
       await peer.transport.readExactly(addr ackMsg[initialSize],
                                          len(ackMsg) - initialSize)
-      ret = handshake.decodeAckMessage(ackMsg)
+    except TransportError:
+      return err(RlpxHandshakeTransportError)
+    except CatchableError as e: # TODO: Only TransportErrors can occur?
+      raiseAssert($e.name & " " & $e.msg)
 
-    if ret.isErr():
+    # TODO: Bullet 1 of https://github.com/status-im/nim-eth/issues/559
-      debug "rlpxConnect handshake error", error = ret.error
+    let res = handshake.decodeAckMessage(ackMsg)
-      if not isNil(peer.transport):
+    if res.isErr():
-        peer.transport.close()
+      debug "rlpxConnect handshake error", error = res.error
-      return nil
+      return err(RlpxHandshakeError)
 
-    ret.get()
+  peer.setSnappySupport(node, handshake)
+  peer.initSecretState(handshake, ^authMsg, ackMsg)
 
-    node.checkSnappySupport(handshake, peer)
-    initSecretState(handshake, ^authMsg, ackMsg, peer)
-
-    # if handshake.remoteHPubkey != remote.node.pubKey:
-    #   raise newException(Exception, "Remote pubkey is wrong")
   logConnectedPeer peer
 
-    var sendHelloFut = peer.hello(
+  # RLPx p2p capability handshake: After the initial handshake, both sides of
+  # the connection must send either Hello or a Disconnect message.
+  let
+    sendHelloFut = peer.hello(
       handshake.getVersion(),
       node.clientId,
       node.capabilities,
       uint(node.address.tcpPort),
       node.keys.pubkey.toRaw())
 
-    var response = await peer.handshakeImpl(
+    receiveHelloFut = peer.waitSingleMsg(DevP2P.hello)
+
+    response =
+      try:
+        await peer.handshakeImpl(
           sendHelloFut,
-      peer.waitSingleMsg(DevP2P.hello),
+          receiveHelloFut,
           10.seconds)
+      except RlpError:
+        return err(ProtocolError)
+      except PeerDisconnected as e:
+        return err(PeerDisconnectedError)
+        # TODO: Strange compiler error
+        # case e.reason:
+        # of HandshakeTimeout:
+        #   # Yeah, a bit odd but in this case PeerDisconnected comes from a
+        #   # timeout on the P2P Hello message. TODO: Clean-up that handshakeImpl
+        #   return err(P2PHandshakeError)
+        # of TooManyPeers:
+        #   return err(TooManyPeersError)
+        # else:
+        #   return err(PeerDisconnectedError)
+      except TransportError:
+        return err(P2PTransportError)
+      except CatchableError as e:
+        raiseAssert($e.name & " " & $e.msg)
 
   if not validatePubKeyInHello(response, remote.node.pubkey):
-      warn "Remote nodeId is not its public key" # XXX: Do we care?
+    warn "Wrong devp2p identity in Hello message"
+    return err(InvalidIdentityError)
 
   trace "DevP2P handshake completed", peer = remote,
     clientId = response.clientId
 
+  try:
     await postHelloSteps(peer, response)
-    ok = true
+  except RlpError:
-    trace "Peer fully connected", peer = remote, clientId = response.clientId
+    return err(ProtocolError)
   except PeerDisconnected as e:
-    case e.reason
+    case e.reason:
-    of AlreadyConnected, TooManyPeers, MessageTimeout:
+    of TooManyPeers:
-      trace "Disconnect during rlpxConnect", reason = e.reason, peer = remote
+      return err(TooManyPeersError)
     else:
-      debug "Unexpected disconnect during rlpxConnect", reason = e.reason,
+      return err(PeerDisconnectedError)
-        msg = e.msg, peer = remote
-  except TransportIncompleteError:
-    trace "Connection dropped in rlpxConnect", remote
   except UselessPeerError:
-    trace "Disconnecting useless peer", peer = remote
+    return err(UselessRlpxPeerError)
-  except RlpTypeMismatch:
+  except TransportError:
-    # Some peers report capabilities with names longer than 3 chars. We ignore
+    return err(P2PTransportError)
-    # those for now. Maybe we should allow this though.
-    debug "Rlp error in rlpxConnect"
-  except TransportOsError as e:
-    trace "TransportOsError", err = e.msg
   except CatchableError as e:
-    error "Unexpected exception in rlpxConnect", remote, exc = e.name,
+    raiseAssert($e.name & " " & $e.msg)
-      err = e.msg
 
-  if not ok:
+  debug "Peer fully connected", peer = remote, clientId = response.clientId
-    if not isNil(peer.transport):
-      peer.transport.close()
-    return nil
-  else:
-    return peer
 
-proc rlpxAccept*(node: EthereumNode,
+  error = false
-                 transport: StreamTransport): Future[Peer] {.async.} =
+
+  return ok(peer)
+
+# TODO: rework rlpxAccept similar to rlpxConnect.
+proc rlpxAccept*(
+    node: EthereumNode, transport: StreamTransport): Future[Peer] {.async.} =
   initTracing(devp2pInfo, node.protocols)
 
   let peer = Peer(transport: transport, network: node)
@@ -1340,11 +1425,14 @@ proc rlpxAccept*(node: EthereumNode,
       trace "rlpxAccept handshake error", error = ret.error
       if not isNil(peer.transport):
         peer.transport.close()
+
+      rlpx_accept_failure.inc()
+      rlpx_accept_failure.inc(labelValues = ["handshake_error"])
       return nil
 
     ret.get()
 
-    node.checkSnappySupport(handshake, peer)
+    peer.setSnappySupport(node, handshake)
     handshake.version = uint8(peer.baseProtocolVersion)
 
     var ackMsg: array[AckMessageMaxEIP8, byte]
@@ -1355,7 +1443,7 @@ proc rlpxAccept*(node: EthereumNode,
       raisePeerDisconnected("Unexpected disconnect while authenticating",
                             TcpError)
 
-    initSecretState(handshake, authMsg, ^ackMsg, peer)
+    peer.initSecretState(handshake, authMsg, ^ackMsg)
 
     let listenPort = transport.localAddress().port
 
@@ -1407,24 +1495,37 @@ proc rlpxAccept*(node: EthereumNode,
       else:
         debug "Unexpected disconnect during rlpxAccept", reason = e.reason,
           msg = e.msg, peer = peer.remote
+
+    rlpx_accept_failure.inc(labelValues = [$e.reason])
   except TransportIncompleteError:
     trace "Connection dropped in rlpxAccept", remote = peer.remote
+    rlpx_accept_failure.inc(labelValues = [$TransportIncompleteError])
   except UselessPeerError:
     trace "Disconnecting useless peer", peer = peer.remote
-  except RlpTypeMismatch:
+    rlpx_accept_failure.inc(labelValues = [$UselessPeerError])
+  except RlpTypeMismatch as e:
     # Some peers report capabilities with names longer than 3 chars. We ignore
     # those for now. Maybe we should allow this though.
-    debug "Rlp error in rlpxAccept"
+    debug "Rlp error in rlpxAccept", err = e.msg, errName = e.name
+    rlpx_accept_failure.inc(labelValues = [$RlpTypeMismatch])
   except TransportOsError as e:
-    trace "TransportOsError", err = e.msg
+    trace "TransportOsError", err = e.msg, errName = e.name
+    if e.code == OSErrorCode(110):
+      rlpx_accept_failure.inc(labelValues = ["tcp_timeout"])
+    else:
+      rlpx_accept_failure.inc(labelValues = [$e.name])
   except CatchableError as e:
     error "Unexpected exception in rlpxAccept", exc = e.name, err = e.msg
+    rlpx_accept_failure.inc(labelValues = [$e.name])
 
   if not ok:
     if not isNil(peer.transport):
       peer.transport.close()
+
+    rlpx_accept_failure.inc()
     return nil
   else:
+    rlpx_accept_success.inc()
     return peer
 
 when isMainModule:

tests/fuzzing/rlpx/thunk.nim

@@ -18,7 +18,11 @@ init:
   node2 = setupTestNode(rng, eth)
 
   node2.startListening()
-  peer = waitFor node1.rlpxConnect(newNode(node2.toENode()))
+  let res = waitFor node1.rlpxConnect(newNode(node2.toENode()))
+  if res.isErr():
+    quit 1
+  else:
+    peer = res.get()
 
 test:
   aflLoop: # This appears to have unstable results with afl-clang-fast, probably

tests/p2p/test_protocol_handlers.nim

@@ -65,9 +65,11 @@ suite "Testing protocol handlers":
     var node2 = setupTestNode(rng, abc, xyz)
 
     node2.startListening()
-    let peer = await node1.rlpxConnect(newNode(node2.toENode()))
+    let res = await node1.rlpxConnect(newNode(node2.toENode()))
     check:
-      peer.isNil == false
+      res.isOk()
+
+    let peer = res.get()
 
     await peer.disconnect(SubprotocolReason, true)
     check:
@@ -82,9 +84,9 @@ suite "Testing protocol handlers":
     var node1 = setupTestNode(rng, hah)
     var node2 = setupTestNode(rng, hah)
     node2.startListening()
-    let peer = await node1.rlpxConnect(newNode(node2.toENode()))
+    let res = await node1.rlpxConnect(newNode(node2.toENode()))
     check:
-      peer.isNil == true
+      res.isErr()
       # To check if the disconnection handler did not run
       node1.protocolState(hah).count == 0
 

tests/p2p/test_rlpx_thunk.nim

@@ -16,7 +16,10 @@ var
   node2 = setupTestNode(rng, eth)
 
 node2.startListening()
-var peer = waitFor node1.rlpxConnect(newNode(node2.toENode()))
+let res = waitFor node1.rlpxConnect(newNode(node2.toENode()))
+check res.isOk()
+
+let peer = res.get()
 
 proc testThunk(payload: openArray[byte]) =
   var (msgId, msgData) = recvMsgMock(payload)