p2p/discv5: fix multiple discovery issues (#16036)

* p2p/discv5: add query delay, fix node address update logic, retry refresh if empty

* p2p/discv5: remove unnecessary ping before topic query

* p2p/discv5: do not filter local address from topicNodes

* p2p/discv5: remove canQuery()

* p2p/discv5: gofmt

3 files changed, 37 insertions, 27 deletions

diff --git a/p2p/discv5/net.go b/p2p/discv5/net.go
index f9baf126f..52c677b62 100644
--- a/p2p/discv5/net.go
+++ b/p2p/discv5/net.go
@@ -565,11 +565,8 @@ loop:
 			if lookupChn := searchInfo[res.target.topic].lookupChn; lookupChn != nil {
 				lookupChn <- net.ticketStore.radius[res.target.topic].converged
 			}
-			net.ticketStore.searchLookupDone(res.target, res.nodes, func(n *Node) []byte {
-				net.ping(n, n.addr())
-				return n.pingEcho
-			}, func(n *Node, topic Topic) []byte {
-				if n.state == known {
+			net.ticketStore.searchLookupDone(res.target, res.nodes, func(n *Node, topic Topic) []byte {
+				if n.state != nil && n.state.canQuery {
 					return net.conn.send(n, topicQueryPacket, topicQuery{Topic: topic}) // TODO: set expiration
 				} else {
 					if n.state == unknown {
@@ -633,15 +630,20 @@ loop:
 			}
 			net.refreshResp <- refreshDone
 		case <-refreshDone:
-			log.Trace("<-net.refreshDone")
-			refreshDone = nil
-			list := searchReqWhenRefreshDone
-			searchReqWhenRefreshDone = nil
-			go func() {
-				for _, req := range list {
-					net.topicSearchReq <- req
-				}
-			}()
+			log.Trace("<-net.refreshDone", "table size", net.tab.count)
+			if net.tab.count != 0 {
+				refreshDone = nil
+				list := searchReqWhenRefreshDone
+				searchReqWhenRefreshDone = nil
+				go func() {
+					for _, req := range list {
+						net.topicSearchReq <- req
+					}
+				}()
+			} else {
+				refreshDone = make(chan struct{})
+				net.refresh(refreshDone)
+			}
 		}
 	}
 	log.Trace("loop stopped")
@@ -751,7 +753,15 @@ func (net *Network) internNodeFromNeighbours(sender *net.UDPAddr, rn rpcNode) (n
 		return n, err
 	}
 	if !n.IP.Equal(rn.IP) || n.UDP != rn.UDP || n.TCP != rn.TCP {
-		err = fmt.Errorf("metadata mismatch: got %v, want %v", rn, n)
+		if n.state == known {
+			// reject address change if node is known by us
+			err = fmt.Errorf("metadata mismatch: got %v, want %v", rn, n)
+		} else {
+			// accept otherwise; this will be handled nicer with signed ENRs
+			n.IP = rn.IP
+			n.UDP = rn.UDP
+			n.TCP = rn.TCP
+		}
 	}
 	return n, err
 }
diff --git a/p2p/discv5/ticket.go b/p2p/discv5/ticket.go
index 37ce8d23c..b3d1ac4ba 100644
--- a/p2p/discv5/ticket.go
+++ b/p2p/discv5/ticket.go
@@ -494,13 +494,13 @@ func (s *ticketStore) registerLookupDone(lookup lookupInfo, nodes []*Node, ping
 	}
 }
 
-func (s *ticketStore) searchLookupDone(lookup lookupInfo, nodes []*Node, ping func(n *Node) []byte, query func(n *Node, topic Topic) []byte) {
+func (s *ticketStore) searchLookupDone(lookup lookupInfo, nodes []*Node, query func(n *Node, topic Topic) []byte) {
 	now := mclock.Now()
 	for i, n := range nodes {
 		if i == 0 || (binary.BigEndian.Uint64(n.sha[:8])^binary.BigEndian.Uint64(lookup.target[:8])) < s.radius[lookup.topic].minRadius {
 			if lookup.radiusLookup {
 				if lastReq, ok := s.nodeLastReq[n]; !ok || time.Duration(now-lastReq.time) > radiusTC {
-					s.nodeLastReq[n] = reqInfo{pingHash: ping(n), lookup: lookup, time: now}
+					s.nodeLastReq[n] = reqInfo{pingHash: nil, lookup: lookup, time: now}
 				}
 			} // else {
 			if s.canQueryTopic(n, lookup.topic) {
diff --git a/p2p/discv5/udp.go b/p2p/discv5/udp.go
index 543771817..6ce72d2c1 100644
--- a/p2p/discv5/udp.go
+++ b/p2p/discv5/udp.go
@@ -49,7 +49,7 @@ var (
 // Timeouts
 const (
 	respTimeout = 500 * time.Millisecond
-	sendTimeout = 500 * time.Millisecond
+	queryDelay  = 1000 * time.Millisecond
 	expiration  = 20 * time.Second
 
 	ntpFailureThreshold = 32               // Continuous timeouts after which to check NTP
@@ -318,20 +318,20 @@ func (t *udp) sendTopicRegister(remote *Node, topics []Topic, idx int, pong []by
 
 func (t *udp) sendTopicNodes(remote *Node, queryHash common.Hash, nodes []*Node) {
 	p := topicNodes{Echo: queryHash}
-	if len(nodes) == 0 {
-		t.sendPacket(remote.ID, remote.addr(), byte(topicNodesPacket), p)
-		return
-	}
-	for i, result := range nodes {
-		if netutil.CheckRelayIP(remote.IP, result.IP) != nil {
-			continue
+	var sent bool
+	for _, result := range nodes {
+		if result.IP.Equal(t.net.tab.self.IP) || netutil.CheckRelayIP(remote.IP, result.IP) == nil {
+			p.Nodes = append(p.Nodes, nodeToRPC(result))
 		}
-		p.Nodes = append(p.Nodes, nodeToRPC(result))
-		if len(p.Nodes) == maxTopicNodes || i == len(nodes)-1 {
+		if len(p.Nodes) == maxTopicNodes {
 			t.sendPacket(remote.ID, remote.addr(), byte(topicNodesPacket), p)
 			p.Nodes = p.Nodes[:0]
+			sent = true
 		}
 	}
+	if !sent || len(p.Nodes) > 0 {
+		t.sendPacket(remote.ID, remote.addr(), byte(topicNodesPacket), p)
+	}
 }
 
 func (t *udp) sendPacket(toid NodeID, toaddr *net.UDPAddr, ptype byte, req interface{}) (hash []byte, err error) {