Only do discovery queries to refresh the table

eth/p2p/discoveryv5/protocol.nim

@@ -98,9 +98,8 @@ const
   findNodeResultLimit = 16 ## Maximum amount of ENRs in the total Nodes messages
   ## that will be processed
   maxNodesPerMessage = 3 ## Maximum amount of ENRs per individual Nodes message
-  lookupInterval = 60.seconds ## Interval of launching a random lookup to
+  refreshInterval = 5.minutes ## Interval of launching a random query to
-  ## populate the routing table. go-ethereum seems to do 3 runs every 30
+  ## refresh the routing table.
-  ## minutes. Trinity starts one every minute.
   revalidateMax = 10000 ## Revalidation of a peer is done between 0 and this
   ## value in milliseconds
   handshakeTimeout* = 2.seconds ## timeout for the reply on the
@@ -118,8 +117,9 @@ type
     routingTable: RoutingTable
     codec*: Codec
     awaitedMessages: Table[(NodeId, RequestId), Future[Option[Message]]]
-    queryLoop: Future[void]
+    refreshLoop: Future[void]
     revalidateLoop: Future[void]
+    lastLookup: chronos.Moment
     bootstrapRecords*: seq[Record]
     rng*: ref BrHmacDrbgContext
 
@@ -717,6 +717,7 @@ proc lookup*(d: Protocol, target: NodeId): Future[seq[Node]]
         if closestNodes.len > BUCKET_SIZE:
           closestNodes.del(closestNodes.high())
 
+  d.lastLookup = now(chronos.Moment)
   return closestNodes
 
 proc query*(d: Protocol, target: NodeId, k = BUCKET_SIZE): Future[seq[Node]]
@@ -765,6 +766,7 @@ proc query*(d: Protocol, target: NodeId, k = BUCKET_SIZE): Future[seq[Node]]
       if not seen.containsOrIncl(n.id):
         queryBuffer.add(n)
 
+  d.lastLookup = now(chronos.Moment)
   return queryBuffer
 
 proc queryRandom*(d: Protocol): Future[seq[Node]]
@@ -777,6 +779,18 @@ proc queryRandom*(d: Protocol): Future[seq[Node]]
 
   return await d.query(id)
 
+proc queryRandom*(d: Protocol, enrField: (string, seq[byte])):
+    Future[seq[Node]] {.async, raises:[Exception, Defect].} =
+  ## Perform a query for a random target, return all nodes discovered which
+  ## contain enrField.
+  let nodes = await d.queryRandom()
+  var filtered: seq[Node]
+  for n in nodes:
+    if n.record.contains(enrField):
+      filtered.add(n)
+
+  return filtered
+
 proc resolve*(d: Protocol, id: NodeId): Future[Option[Node]]
     {.async, raises: [Exception, Defect].} =
   ## Resolve a `Node` based on provided `NodeId`.
@@ -816,6 +830,8 @@ proc revalidateNode*(d: Protocol, n: Node)
         discard d.addNode(nodes[][0])
 
 proc revalidateLoop(d: Protocol) {.async, raises: [Exception, Defect].} =
+  ## Loop which revalidates the nodes in the routing table by sending the ping
+  ## message.
   # TODO: General Exception raised.
   try:
     while true:
@@ -826,19 +842,24 @@ proc revalidateLoop(d: Protocol) {.async, raises: [Exception, Defect].} =
   except CancelledError:
     trace "revalidateLoop canceled"
 
-proc queryLoop(d: Protocol) {.async, raises: [Exception, Defect].} =
+proc refreshLoop(d: Protocol) {.async, raises: [Exception, Defect].} =
+  ## Loop that refreshes the routing table by starting a random query in case
+  ## no queries were done since `refreshInterval` or more.
   # TODO: General Exception raised.
   try:
-    # query target self (neighbour nodes)
+    # start with a query target self (neighbour nodes)
     let selfQuery = await d.query(d.localNode.id)
     trace "Discovered nodes in self target query", nodes = selfQuery.len
     while true:
+      let currentTime = now(chronos.Moment)
+      if currentTime > (d.lastLookup + refreshInterval):
         let randomQuery = await d.queryRandom()
         trace "Discovered nodes in random target query", nodes = randomQuery.len
         debug "Total nodes in discv5 routing table", total = d.routingTable.len()
-      await sleepAsync(lookupInterval)
+
+      await sleepAsync(refreshInterval)
   except CancelledError:
-    trace "queryLoop canceled"
+    trace "refreshLoop canceled"
 
 proc newProtocol*(privKey: PrivateKey,
                   externalIp: Option[ValidIpAddress], tcpPort, udpPort: Port,
@@ -901,7 +922,7 @@ proc open*(d: Protocol) {.raises: [Exception, Defect].} =
       debug "Bootstrap node could not be added", uri = toURI(record)
 
 proc start*(d: Protocol) {.raises: [Exception, Defect].} =
-  d.queryLoop = queryLoop(d)
+  d.refreshLoop = refreshLoop(d)
   d.revalidateLoop = revalidateLoop(d)
 
 proc close*(d: Protocol) {.raises: [Exception, Defect].} =
@@ -910,8 +931,8 @@ proc close*(d: Protocol) {.raises: [Exception, Defect].} =
   debug "Closing discovery node", node = d.localNode
   if not d.revalidateLoop.isNil:
     d.revalidateLoop.cancel()
-  if not d.queryLoop.isNil:
+  if not d.refreshLoop.isNil:
-    d.queryLoop.cancel()
+    d.refreshLoop.cancel()
 
   d.transp.close()
 
@@ -921,7 +942,7 @@ proc closeWait*(d: Protocol) {.async, raises: [Exception, Defect].} =
   debug "Closing discovery node", node = d.localNode
   if not d.revalidateLoop.isNil:
     await d.revalidateLoop.cancelAndWait()
-  if not d.queryLoop.isNil:
+  if not d.refreshLoop.isNil:
-    await d.queryLoop.cancelAndWait()
+    await d.refreshLoop.cancelAndWait()
 
   await d.transp.closeWait()