p2p/discv5: fix reg lookup, polish code, use logger (#15737)

4 files changed, 139 insertions, 142 deletions

diff --git a/p2p/discv5/net.go b/p2p/discv5/net.go
index 2fbb60824..cd9981584 100644
--- a/p2p/discv5/net.go
+++ b/p2p/discv5/net.go
@@ -51,16 +51,9 @@ const (
 const testTopic = "foo"
 
 const (
-	printDebugLogs   = false
 	printTestImgLogs = false
 )
 
-func debugLog(s string) {
-	if printDebugLogs {
-		fmt.Println(s)
-	}
-}
-
 // Network manages the table and all protocol interaction.
 type Network struct {
 	db          *nodeDB // database of known nodes
@@ -388,14 +381,14 @@ func (net *Network) loop() {
 		}
 	}()
 	resetNextTicket := func() {
-		t, timeout := net.ticketStore.nextFilteredTicket()
-		if t != nextTicket {
-			nextTicket = t
+		ticket, timeout := net.ticketStore.nextFilteredTicket()
+		if nextTicket != ticket {
+			nextTicket = ticket
 			if nextRegisterTimer != nil {
 				nextRegisterTimer.Stop()
 				nextRegisterTime = nil
 			}
-			if t != nil {
+			if ticket != nil {
 				nextRegisterTimer = time.NewTimer(timeout)
 				nextRegisterTime = nextRegisterTimer.C
 			}
@@ -423,13 +416,13 @@ loop:
 
 		select {
 		case <-net.closeReq:
-			debugLog("<-net.closeReq")
+			log.Trace("<-net.closeReq")
 			break loop
 
 		// Ingress packet handling.
 		case pkt := <-net.read:
 			//fmt.Println("read", pkt.ev)
-			debugLog("<-net.read")
+			log.Trace("<-net.read")
 			n := net.internNode(&pkt)
 			prestate := n.state
 			status := "ok"
@@ -444,7 +437,7 @@ loop:
 
 		// State transition timeouts.
 		case timeout := <-net.timeout:
-			debugLog("<-net.timeout")
+			log.Trace("<-net.timeout")
 			if net.timeoutTimers[timeout] == nil {
 				// Stale timer (was aborted).
 				continue
@@ -462,20 +455,20 @@ loop:
 
 		// Querying.
 		case q := <-net.queryReq:
-			debugLog("<-net.queryReq")
+			log.Trace("<-net.queryReq")
 			if !q.start(net) {
 				q.remote.deferQuery(q)
 			}
 
 		// Interacting with the table.
 		case f := <-net.tableOpReq:
-			debugLog("<-net.tableOpReq")
+			log.Trace("<-net.tableOpReq")
 			f()
 			net.tableOpResp <- struct{}{}
 
 		// Topic registration stuff.
 		case req := <-net.topicRegisterReq:
-			debugLog("<-net.topicRegisterReq")
+			log.Trace("<-net.topicRegisterReq")
 			if !req.add {
 				net.ticketStore.removeRegisterTopic(req.topic)
 				continue
@@ -486,7 +479,7 @@ loop:
 			// determination for new topics.
 			// if topicRegisterLookupDone == nil {
 			if topicRegisterLookupTarget.target == (common.Hash{}) {
-				debugLog("topicRegisterLookupTarget == null")
+				log.Trace("topicRegisterLookupTarget == null")
 				if topicRegisterLookupTick.Stop() {
 					<-topicRegisterLookupTick.C
 				}
@@ -496,7 +489,7 @@ loop:
 			}
 
 		case nodes := <-topicRegisterLookupDone:
-			debugLog("<-topicRegisterLookupDone")
+			log.Trace("<-topicRegisterLookupDone")
 			net.ticketStore.registerLookupDone(topicRegisterLookupTarget, nodes, func(n *Node) []byte {
 				net.ping(n, n.addr())
 				return n.pingEcho
@@ -507,7 +500,7 @@ loop:
 			topicRegisterLookupDone = nil
 
 		case <-topicRegisterLookupTick.C:
-			debugLog("<-topicRegisterLookupTick")
+			log.Trace("<-topicRegisterLookupTick")
 			if (topicRegisterLookupTarget.target == common.Hash{}) {
 				target, delay := net.ticketStore.nextRegisterLookup()
 				topicRegisterLookupTarget = target
@@ -520,14 +513,14 @@ loop:
 			}
 
 		case <-nextRegisterTime:
-			debugLog("<-nextRegisterTime")
+			log.Trace("<-nextRegisterTime")
 			net.ticketStore.ticketRegistered(*nextTicket)
 			//fmt.Println("sendTopicRegister", nextTicket.t.node.addr().String(), nextTicket.t.topics, nextTicket.idx, nextTicket.t.pong)
 			net.conn.sendTopicRegister(nextTicket.t.node, nextTicket.t.topics, nextTicket.idx, nextTicket.t.pong)
 
 		case req := <-net.topicSearchReq:
 			if refreshDone == nil {
-				debugLog("<-net.topicSearchReq")
+				log.Trace("<-net.topicSearchReq")
 				info, ok := searchInfo[req.topic]
 				if ok {
 					if req.delay == time.Duration(0) {
@@ -588,7 +581,7 @@ loop:
 			})
 
 		case <-statsDump.C:
-			debugLog("<-statsDump.C")
+			log.Trace("<-statsDump.C")
 			/*r, ok := net.ticketStore.radius[testTopic]
 			if !ok {
 				fmt.Printf("(%x) no radius @ %v\n", net.tab.self.ID[:8], time.Now())
@@ -617,7 +610,7 @@ loop:
 
 		// Periodic / lookup-initiated bucket refresh.
 		case <-refreshTimer.C:
-			debugLog("<-refreshTimer.C")
+			log.Trace("<-refreshTimer.C")
 			// TODO: ideally we would start the refresh timer after
 			// fallback nodes have been set for the first time.
 			if refreshDone == nil {
@@ -631,7 +624,7 @@ loop:
 				bucketRefreshTimer.Reset(bucketRefreshInterval)
 			}()
 		case newNursery := <-net.refreshReq:
-			debugLog("<-net.refreshReq")
+			log.Trace("<-net.refreshReq")
 			if newNursery != nil {
 				net.nursery = newNursery
 			}
@@ -641,7 +634,7 @@ loop:
 			}
 			net.refreshResp <- refreshDone
 		case <-refreshDone:
-			debugLog("<-net.refreshDone")
+			log.Trace("<-net.refreshDone")
 			refreshDone = nil
 			list := searchReqWhenRefreshDone
 			searchReqWhenRefreshDone = nil
@@ -652,7 +645,7 @@ loop:
 			}()
 		}
 	}
-	debugLog("loop stopped")
+	log.Trace("loop stopped")
 
 	log.Debug(fmt.Sprintf("shutting down"))
 	if net.conn != nil {
@@ -1109,14 +1102,14 @@ func (net *Network) ping(n *Node, addr *net.UDPAddr) {
 		//fmt.Println(" not sent")
 		return
 	}
-	debugLog(fmt.Sprintf("ping(node = %x)", n.ID[:8]))
+	log.Trace("Pinging remote node", "node", n.ID)
 	n.pingTopics = net.ticketStore.regTopicSet()
 	n.pingEcho = net.conn.sendPing(n, addr, n.pingTopics)
 	net.timedEvent(respTimeout, n, pongTimeout)
 }
 
 func (net *Network) handlePing(n *Node, pkt *ingressPacket) {
-	debugLog(fmt.Sprintf("handlePing(node = %x)", n.ID[:8]))
+	log.Trace("Handling remote ping", "node", n.ID)
 	ping := pkt.data.(*ping)
 	n.TCP = ping.From.TCP
 	t := net.topictab.getTicket(n, ping.Topics)
@@ -1131,7 +1124,7 @@ func (net *Network) handlePing(n *Node, pkt *ingressPacket) {
 }
 
 func (net *Network) handleKnownPong(n *Node, pkt *ingressPacket) error {
-	debugLog(fmt.Sprintf("handleKnownPong(node = %x)", n.ID[:8]))
+	log.Trace("Handling known pong", "node", n.ID)
 	net.abortTimedEvent(n, pongTimeout)
 	now := mclock.Now()
 	ticket, err := pongToTicket(now, n.pingTopics, n, pkt)
@@ -1139,9 +1132,8 @@ func (net *Network) handleKnownPong(n *Node, pkt *ingressPacket) error {
 		// fmt.Printf("(%x) ticket: %+v\n", net.tab.self.ID[:8], pkt.data)
 		net.ticketStore.addTicket(now, pkt.data.(*pong).ReplyTok, ticket)
 	} else {
-		debugLog(fmt.Sprintf(" error: %v", err))
+		log.Trace("Failed to convert pong to ticket", "err", err)
 	}
-
 	n.pingEcho = nil
 	n.pingTopics = nil
 	return err
diff --git a/p2p/discv5/node.go b/p2p/discv5/node.go
index 2db7a508f..fd88a55b1 100644
--- a/p2p/discv5/node.go
+++ b/p2p/discv5/node.go
@@ -273,6 +273,11 @@ func (n NodeID) GoString() string {
 	return fmt.Sprintf("discover.HexID(\"%x\")", n[:])
 }
 
+// TerminalString returns a shortened hex string for terminal logging.
+func (n NodeID) TerminalString() string {
+	return hex.EncodeToString(n[:8])
+}
+
 // HexID converts a hex string to a NodeID.
 // The string may be prefixed with 0x.
 func HexID(in string) (NodeID, error) {
diff --git a/p2p/discv5/ticket.go b/p2p/discv5/ticket.go
index 193cef4be..b45ec4d2b 100644
--- a/p2p/discv5/ticket.go
+++ b/p2p/discv5/ticket.go
@@ -28,6 +28,7 @@ import (
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/common/mclock"
 	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/ethereum/go-ethereum/log"
 )
 
 const (
@@ -128,8 +129,11 @@ type ticketStore struct {
 	// Contains buckets (for each absolute minute) of tickets
 	// that can be used in that minute.
 	// This is only set if the topic is being registered.
-	tickets     map[Topic]topicTickets
-	regtopics   []Topic
+	tickets map[Topic]*topicTickets
+
+	regQueue []Topic            // Topic registration queue for round robin attempts
+	regSet   map[Topic]struct{} // Topic registration queue contents for fast filling
+
 	nodes       map[*Node]*ticket
 	nodeLastReq map[*Node]reqInfo
 
@@ -152,14 +156,16 @@ type sentQuery struct {
 }
 
 type topicTickets struct {
-	buckets             map[timeBucket][]ticketRef
-	nextLookup, nextReg mclock.AbsTime
+	buckets    map[timeBucket][]ticketRef
+	nextLookup mclock.AbsTime
+	nextReg    mclock.AbsTime
 }
 
 func newTicketStore() *ticketStore {
 	return &ticketStore{
 		radius:         make(map[Topic]*topicRadius),
-		tickets:        make(map[Topic]topicTickets),
+		tickets:        make(map[Topic]*topicTickets),
+		regSet:         make(map[Topic]struct{}),
 		nodes:          make(map[*Node]*ticket),
 		nodeLastReq:    make(map[*Node]reqInfo),
 		searchTopicMap: make(map[Topic]searchTopic),
@@ -169,13 +175,13 @@ func newTicketStore() *ticketStore {
 
 // addTopic starts tracking a topic. If register is true,
 // the local node will register the topic and tickets will be collected.
-func (s *ticketStore) addTopic(t Topic, register bool) {
-	debugLog(fmt.Sprintf(" addTopic(%v, %v)", t, register))
-	if s.radius[t] == nil {
-		s.radius[t] = newTopicRadius(t)
+func (s *ticketStore) addTopic(topic Topic, register bool) {
+	log.Trace("Adding discovery topic", "topic", topic, "register", register)
+	if s.radius[topic] == nil {
+		s.radius[topic] = newTopicRadius(topic)
 	}
-	if register && s.tickets[t].buckets == nil {
-		s.tickets[t] = topicTickets{buckets: make(map[timeBucket][]ticketRef)}
+	if register && s.tickets[topic] == nil {
+		s.tickets[topic] = &topicTickets{buckets: make(map[timeBucket][]ticketRef)}
 	}
 }
 
@@ -194,7 +200,11 @@ func (s *ticketStore) removeSearchTopic(t Topic) {
 
 // removeRegisterTopic deletes all tickets for the given topic.
 func (s *ticketStore) removeRegisterTopic(topic Topic) {
-	debugLog(fmt.Sprintf(" removeRegisterTopic(%v)", topic))
+	log.Trace("Removing discovery topic", "topic", topic)
+	if s.tickets[topic] == nil {
+		log.Warn("Removing non-existent discovery topic", "topic", topic)
+		return
+	}
 	for _, list := range s.tickets[topic].buckets {
 		for _, ref := range list {
 			ref.t.refCnt--
@@ -216,23 +226,35 @@ func (s *ticketStore) regTopicSet() []Topic {
 }
 
 // nextRegisterLookup returns the target of the next lookup for ticket collection.
-func (s *ticketStore) nextRegisterLookup() (lookup lookupInfo, delay time.Duration) {
-	debugLog("nextRegisterLookup()")
-	firstTopic, ok := s.iterRegTopics()
-	for topic := firstTopic; ok; {
-		debugLog(fmt.Sprintf(" checking topic %v, len(s.tickets[topic]) = %d", topic, len(s.tickets[topic].buckets)))
-		if s.tickets[topic].buckets != nil && s.needMoreTickets(topic) {
-			next := s.radius[topic].nextTarget(false)
-			debugLog(fmt.Sprintf(" %x 1s", next.target[:8]))
-			return next, 100 * time.Millisecond
+func (s *ticketStore) nextRegisterLookup() (lookupInfo, time.Duration) {
+	// Queue up any new topics (or discarded ones), preserving iteration order
+	for topic := range s.tickets {
+		if _, ok := s.regSet[topic]; !ok {
+			s.regQueue = append(s.regQueue, topic)
+			s.regSet[topic] = struct{}{}
 		}
-		topic, ok = s.iterRegTopics()
-		if topic == firstTopic {
-			break // We have checked all topics.
+	}
+	// Iterate over the set of all topics and look up the next suitable one
+	for len(s.regQueue) > 0 {
+		// Fetch the next topic from the queue, and ensure it still exists
+		topic := s.regQueue[0]
+		s.regQueue = s.regQueue[1:]
+		delete(s.regSet, topic)
+
+		if s.tickets[topic] == nil {
+			continue
+		}
+		// If the topic needs more tickets, return it
+		if s.tickets[topic].nextLookup < mclock.Now() {
+			next, delay := s.radius[topic].nextTarget(false), 100*time.Millisecond
+			log.Trace("Found discovery topic to register", "topic", topic, "target", next.target, "delay", delay)
+			return next, delay
 		}
 	}
-	debugLog(" null, 40s")
-	return lookupInfo{}, 40 * time.Second
+	// No registration topics found or all exhausted, sleep
+	delay := 40 * time.Second
+	log.Trace("No topic found to register", "delay", delay)
+	return lookupInfo{}, delay
 }
 
 func (s *ticketStore) nextSearchLookup(topic Topic) lookupInfo {
@@ -246,40 +268,22 @@ func (s *ticketStore) nextSearchLookup(topic Topic) lookupInfo {
 	return target
 }
 
-// iterRegTopics returns topics to register in arbitrary order.
-// The second return value is false if there are no topics.
-func (s *ticketStore) iterRegTopics() (Topic, bool) {
-	debugLog("iterRegTopics()")
-	if len(s.regtopics) == 0 {
-		if len(s.tickets) == 0 {
-			debugLog(" false")
-			return "", false
-		}
-		// Refill register list.
-		for t := range s.tickets {
-			s.regtopics = append(s.regtopics, t)
-		}
+// ticketsInWindow returns the tickets of a given topic in the registration window.
+func (s *ticketStore) ticketsInWindow(topic Topic) []ticketRef {
+	// Sanity check that the topic still exists before operating on it
+	if s.tickets[topic] == nil {
+		log.Warn("Listing non-existing discovery tickets", "topic", topic)
+		return nil
 	}
-	topic := s.regtopics[len(s.regtopics)-1]
-	s.regtopics = s.regtopics[:len(s.regtopics)-1]
-	debugLog(" " + string(topic) + " true")
-	return topic, true
-}
-
-func (s *ticketStore) needMoreTickets(t Topic) bool {
-	return s.tickets[t].nextLookup < mclock.Now()
-}
+	// Gather all the tickers in the next time window
+	var tickets []ticketRef
 
-// ticketsInWindow returns the tickets of a given topic in the registration window.
-func (s *ticketStore) ticketsInWindow(t Topic) []ticketRef {
-	ltBucket := s.lastBucketFetched
-	var res []ticketRef
-	tickets := s.tickets[t].buckets
-	for g := ltBucket; g < ltBucket+timeWindow; g++ {
-		res = append(res, tickets[g]...)
+	buckets := s.tickets[topic].buckets
+	for idx := timeBucket(0); idx < timeWindow; idx++ {
+		tickets = append(tickets, buckets[s.lastBucketFetched+idx]...)
 	}
-	debugLog(fmt.Sprintf("ticketsInWindow(%v) = %v", t, len(res)))
-	return res
+	log.Trace("Retrieved discovery registration tickets", "topic", topic, "from", s.lastBucketFetched, "tickets", len(tickets))
+	return tickets
 }
 
 func (s *ticketStore) removeExcessTickets(t Topic) {
@@ -317,53 +321,55 @@ func (s ticketRefByWaitTime) Swap(i, j int) {
 
 func (s *ticketStore) addTicketRef(r ticketRef) {
 	topic := r.t.topics[r.idx]
-	t := s.tickets[topic]
-	if t.buckets == nil {
+	tickets := s.tickets[topic]
+	if tickets == nil {
+		log.Warn("Adding ticket to non-existent topic", "topic", topic)
 		return
 	}
 	bucket := timeBucket(r.t.regTime[r.idx] / mclock.AbsTime(ticketTimeBucketLen))
-	t.buckets[bucket] = append(t.buckets[bucket], r)
+	tickets.buckets[bucket] = append(tickets.buckets[bucket], r)
 	r.t.refCnt++
 
 	min := mclock.Now() - mclock.AbsTime(collectFrequency)*maxCollectDebt
-	if t.nextLookup < min {
-		t.nextLookup = min
+	if tickets.nextLookup < min {
+		tickets.nextLookup = min
 	}
-	t.nextLookup += mclock.AbsTime(collectFrequency)
-	s.tickets[topic] = t
+	tickets.nextLookup += mclock.AbsTime(collectFrequency)
 
 	//s.removeExcessTickets(topic)
 }
 
-func (s *ticketStore) nextFilteredTicket() (t *ticketRef, wait time.Duration) {
+func (s *ticketStore) nextFilteredTicket() (*ticketRef, time.Duration) {
 	now := mclock.Now()
 	for {
-		t, wait = s.nextRegisterableTicket()
-		if t == nil {
-			return
+		ticket, wait := s.nextRegisterableTicket()
+		if ticket == nil {
+			return ticket, wait
 		}
+		log.Trace("Found discovery ticket to register", "node", ticket.t.node, "serial", ticket.t.serial, "wait", wait)
+
 		regTime := now + mclock.AbsTime(wait)
-		topic := t.t.topics[t.idx]
+		topic := ticket.t.topics[ticket.idx]
 		if regTime >= s.tickets[topic].nextReg {
-			return
+			return ticket, wait
 		}
-		s.removeTicketRef(*t)
+		s.removeTicketRef(*ticket)
 	}
 }
 
-func (s *ticketStore) ticketRegistered(t ticketRef) {
+func (s *ticketStore) ticketRegistered(ref ticketRef) {
 	now := mclock.Now()
 
-	topic := t.t.topics[t.idx]
-	tt := s.tickets[topic]
+	topic := ref.t.topics[ref.idx]
+	tickets := s.tickets[topic]
 	min := now - mclock.AbsTime(registerFrequency)*maxRegisterDebt
-	if min > tt.nextReg {
-		tt.nextReg = min
+	if min > tickets.nextReg {
+		tickets.nextReg = min
 	}
-	tt.nextReg += mclock.AbsTime(registerFrequency)
-	s.tickets[topic] = tt
+	tickets.nextReg += mclock.AbsTime(registerFrequency)
+	s.tickets[topic] = tickets
 
-	s.removeTicketRef(t)
+	s.removeTicketRef(ref)
 }
 
 // nextRegisterableTicket returns the next ticket that can be used
@@ -374,16 +380,7 @@ func (s *ticketStore) ticketRegistered(t ticketRef) {
 //
 // A ticket can be returned more than once with <= zero wait time in case
 // the ticket contains multiple topics.
-func (s *ticketStore) nextRegisterableTicket() (t *ticketRef, wait time.Duration) {
-	defer func() {
-		if t == nil {
-			debugLog(" nil")
-		} else {
-			debugLog(fmt.Sprintf(" node = %x sn = %v wait = %v", t.t.node.ID[:8], t.t.serial, wait))
-		}
-	}()
-
-	debugLog("nextRegisterableTicket()")
+func (s *ticketStore) nextRegisterableTicket() (*ticketRef, time.Duration) {
 	now := mclock.Now()
 	if s.nextTicketCached != nil {
 		return s.nextTicketCached, time.Duration(s.nextTicketCached.topicRegTime() - now)
@@ -412,9 +409,8 @@ func (s *ticketStore) nextRegisterableTicket() (t *ticketRef, wait time.Duration
 			return nil, 0
 		}
 		if nextTicket.t != nil {
-			wait = time.Duration(nextTicket.topicRegTime() - now)
 			s.nextTicketCached = &nextTicket
-			return &nextTicket, wait
+			return &nextTicket, time.Duration(nextTicket.topicRegTime() - now)
 		}
 		s.lastBucketFetched = bucket
 	}
@@ -422,14 +418,17 @@ func (s *ticketStore) nextRegisterableTicket() (t *ticketRef, wait time.Duration
 
 // removeTicket removes a ticket from the ticket store
 func (s *ticketStore) removeTicketRef(ref ticketRef) {
-	debugLog(fmt.Sprintf("removeTicketRef(node = %x sn = %v)", ref.t.node.ID[:8], ref.t.serial))
+	log.Trace("Removing discovery ticket reference", "node", ref.t.node.ID, "serial", ref.t.serial)
+
 	topic := ref.topic()
-	tickets := s.tickets[topic].buckets
+	tickets := s.tickets[topic]
+
 	if tickets == nil {
+		log.Warn("Removing tickets from unknown topic", "topic", topic)
 		return
 	}
 	bucket := timeBucket(ref.t.regTime[ref.idx] / mclock.AbsTime(ticketTimeBucketLen))
-	list := tickets[bucket]
+	list := tickets.buckets[bucket]
 	idx := -1
 	for i, bt := range list {
 		if bt.t == ref.t {
@@ -442,9 +441,9 @@ func (s *ticketStore) removeTicketRef(ref ticketRef) {
 	}
 	list = append(list[:idx], list[idx+1:]...)
 	if len(list) != 0 {
-		tickets[bucket] = list
+		tickets.buckets[bucket] = list
 	} else {
-		delete(tickets, bucket)
+		delete(tickets.buckets, bucket)
 	}
 	ref.t.refCnt--
 	if ref.t.refCnt == 0 {
@@ -523,21 +522,21 @@ func (s *ticketStore) adjustWithTicket(now mclock.AbsTime, targetHash common.Has
 	}
 }
 
-func (s *ticketStore) addTicket(localTime mclock.AbsTime, pingHash []byte, t *ticket) {
-	debugLog(fmt.Sprintf("add(node = %x sn = %v)", t.node.ID[:8], t.serial))
+func (s *ticketStore) addTicket(localTime mclock.AbsTime, pingHash []byte, ticket *ticket) {
+	log.Trace("Adding discovery ticket", "node", ticket.node.ID, "serial", ticket.serial)
 
-	lastReq, ok := s.nodeLastReq[t.node]
+	lastReq, ok := s.nodeLastReq[ticket.node]
 	if !(ok && bytes.Equal(pingHash, lastReq.pingHash)) {
 		return
 	}
-	s.adjustWithTicket(localTime, lastReq.lookup.target, t)
+	s.adjustWithTicket(localTime, lastReq.lookup.target, ticket)
 
-	if lastReq.lookup.radiusLookup || s.nodes[t.node] != nil {
+	if lastReq.lookup.radiusLookup || s.nodes[ticket.node] != nil {
 		return
 	}
 
 	topic := lastReq.lookup.topic
-	topicIdx := t.findIdx(topic)
+	topicIdx := ticket.findIdx(topic)
 	if topicIdx == -1 {
 		return
 	}
@@ -548,29 +547,29 @@ func (s *ticketStore) addTicket(localTime mclock.AbsTime, pingHash []byte, t *ti
 	}
 
 	if _, ok := s.tickets[topic]; ok {
-		wait := t.regTime[topicIdx] - localTime
+		wait := ticket.regTime[topicIdx] - localTime
 		rnd := rand.ExpFloat64()
 		if rnd > 10 {
 			rnd = 10
 		}
 		if float64(wait) < float64(keepTicketConst)+float64(keepTicketExp)*rnd {
 			// use the ticket to register this topic
-			//fmt.Println("addTicket", t.node.ID[:8], t.node.addr().String(), t.serial, t.pong)
-			s.addTicketRef(ticketRef{t, topicIdx})
+			//fmt.Println("addTicket", ticket.node.ID[:8], ticket.node.addr().String(), ticket.serial, ticket.pong)
+			s.addTicketRef(ticketRef{ticket, topicIdx})
 		}
 	}
 
-	if t.refCnt > 0 {
+	if ticket.refCnt > 0 {
 		s.nextTicketCached = nil
-		s.nodes[t.node] = t
+		s.nodes[ticket.node] = ticket
 	}
 }
 
 func (s *ticketStore) getNodeTicket(node *Node) *ticket {
 	if s.nodes[node] == nil {
-		debugLog(fmt.Sprintf("getNodeTicket(%x) sn = nil", node.ID[:8]))
+		log.Trace("Retrieving node ticket", "node", node.ID, "serial", nil)
 	} else {
-		debugLog(fmt.Sprintf("getNodeTicket(%x) sn = %v", node.ID[:8], s.nodes[node].serial))
+		log.Trace("Retrieving node ticket", "node", node.ID, "serial", s.nodes[node].serial)
 	}
 	return s.nodes[node]
 }
diff --git a/p2p/discv5/topic.go b/p2p/discv5/topic.go
index b6bea013c..e7a7f8e02 100644
--- a/p2p/discv5/topic.go
+++ b/p2p/discv5/topic.go
@@ -24,6 +24,7 @@ import (
 	"time"
 
 	"github.com/ethereum/go-ethereum/common/mclock"
+	"github.com/ethereum/go-ethereum/log"
 )
 
 const (
@@ -235,7 +236,7 @@ func (t *topicTable) deleteEntry(e *topicEntry) {
 
 // It is assumed that topics and waitPeriods have the same length.
 func (t *topicTable) useTicket(node *Node, serialNo uint32, topics []Topic, idx int, issueTime uint64, waitPeriods []uint32) (registered bool) {
-	debugLog(fmt.Sprintf("useTicket %v %v %v", serialNo, topics, waitPeriods))
+	log.Trace("Using discovery ticket", "serial", serialNo, "topics", topics, "waits", waitPeriods)
 	//fmt.Println("useTicket", serialNo, topics, waitPeriods)
 	t.collectGarbage()