p2p/discv5: add deprecation warning and remove unused code (#20367)

* p2p/discv5: add deprecation warning and remove unused code

* p2p/discv5: remove unused variables

p2p/discv5/README

+This package is an early prototype of Discovery v5. Do not use this code.
+
+See https://github.com/ethereum/devp2p/blob/master/discv5/discv5.md for the
+current Discovery v5 specification.
\ No newline at end of file

p2p/discv5/database.go

@@ -58,12 +58,11 @@ var (
 	nodeDBVersionKey = []byte("version") // Version of the database to flush if changes
 	nodeDBItemPrefix = []byte("n:")      // Identifier to prefix node entries with
 
-	nodeDBDiscoverRoot          = ":discover"
-	nodeDBDiscoverPing          = nodeDBDiscoverRoot + ":lastping"
-	nodeDBDiscoverPong          = nodeDBDiscoverRoot + ":lastpong"
-	nodeDBDiscoverFindFails     = nodeDBDiscoverRoot + ":findfail"
-	nodeDBDiscoverLocalEndpoint = nodeDBDiscoverRoot + ":localendpoint"
-	nodeDBTopicRegTickets       = ":tickets"
+	nodeDBDiscoverRoot      = ":discover"
+	nodeDBDiscoverPing      = nodeDBDiscoverRoot + ":lastping"
+	nodeDBDiscoverPong      = nodeDBDiscoverRoot + ":lastpong"
+	nodeDBDiscoverFindFails = nodeDBDiscoverRoot + ":findfail"
+	nodeDBTopicRegTickets   = ":tickets"
 )
 
 // newNodeDB creates a new node database for storing and retrieving infos about
@@ -311,20 +310,6 @@ func (db *nodeDB) updateFindFails(id NodeID, fails int) error {
 	return db.storeInt64(makeKey(id, nodeDBDiscoverFindFails), int64(fails))
 }
 
-// localEndpoint returns the last local endpoint communicated to the
-// given remote node.
-func (db *nodeDB) localEndpoint(id NodeID) *rpcEndpoint {
-	var ep rpcEndpoint
-	if err := db.fetchRLP(makeKey(id, nodeDBDiscoverLocalEndpoint), &ep); err != nil {
-		return nil
-	}
-	return &ep
-}
-
-func (db *nodeDB) updateLocalEndpoint(id NodeID, ep rpcEndpoint) error {
-	return db.storeRLP(makeKey(id, nodeDBDiscoverLocalEndpoint), &ep)
-}
-
 // querySeeds retrieves random nodes to be used as potential seed nodes
 // for bootstrapping.
 func (db *nodeDB) querySeeds(n int, maxAge time.Duration) []*Node {

p2p/discv5/net.go

@@ -77,14 +77,6 @@ type Network struct {
 	nursery       []*Node
 	nodes         map[NodeID]*Node // tracks active nodes with state != known
 	timeoutTimers map[timeoutEvent]*time.Timer
-
-	// Revalidation queues.
-	// Nodes put on these queues will be pinged eventually.
-	slowRevalidateQueue []*Node
-	fastRevalidateQueue []*Node
-
-	// Buffers for state transition.
-	sendBuf []*ingressPacket
 }
 
 // transport is implemented by the UDP transport.
@@ -104,10 +96,9 @@ type transport interface {
 }
 
 type findnodeQuery struct {
-	remote   *Node
-	target   common.Hash
-	reply    chan<- []*Node
-	nresults int // counter for received nodes
+	remote *Node
+	target common.Hash
+	reply  chan<- []*Node
 }
 
 type topicRegisterReq struct {
@@ -650,10 +641,10 @@ loop:
 	if net.conn != nil {
 		net.conn.Close()
 	}
-	if refreshDone != nil {
-		// TODO: wait for pending refresh.
-		//<-refreshResults
-	}
+	// TODO: wait for pending refresh.
+	// if refreshDone != nil {
+	// 	<-refreshResults
+	// }
 	// Cancel all pending timeouts.
 	for _, timer := range net.timeoutTimers {
 		timer.Stop()

p2p/discv5/net_test.go

@@ -17,7 +17,6 @@
 package discv5
 
 import (
-	"fmt"
 	"net"
 	"testing"
 	"time"
@@ -265,10 +264,6 @@ type preminedTestnet struct {
 	net       *Network
 }
 
-func (tn *preminedTestnet) sendFindnode(to *Node, target NodeID) {
-	panic("sendFindnode called")
-}
-
 func (tn *preminedTestnet) sendFindnodeHash(to *Node, target common.Hash) {
 	// current log distance is encoded in port number
 	// fmt.Println("findnode query at dist", toaddr.Port)
@@ -316,10 +311,6 @@ func (tn *preminedTestnet) sendNeighbours(to *Node, nodes []*Node) {
 	panic("sendNeighbours called")
 }
 
-func (tn *preminedTestnet) sendTopicQuery(to *Node, topic Topic) {
-	panic("sendTopicQuery called")
-}
-
 func (tn *preminedTestnet) sendTopicNodes(to *Node, queryHash common.Hash, nodes []*Node) {
 	panic("sendTopicNodes called")
 }
@@ -334,41 +325,6 @@ func (*preminedTestnet) localAddr() *net.UDPAddr {
 	return &net.UDPAddr{IP: net.ParseIP("10.0.1.1"), Port: 40000}
 }
 
-// mine generates a testnet struct literal with nodes at
-// various distances to the given target.
-func (tn *preminedTestnet) mine(target NodeID) {
-	tn.target = target
-	tn.targetSha = crypto.Keccak256Hash(tn.target[:])
-	found := 0
-	for found < bucketSize*10 {
-		k := newkey()
-		id := PubkeyID(&k.PublicKey)
-		sha := crypto.Keccak256Hash(id[:])
-		ld := logdist(tn.targetSha, sha)
-		if len(tn.dists[ld]) < bucketSize {
-			tn.dists[ld] = append(tn.dists[ld], id)
-			fmt.Println("found ID with ld", ld)
-			found++
-		}
-	}
-	fmt.Println("&preminedTestnet{")
-	fmt.Printf("	target: %#v,\n", tn.target)
-	fmt.Printf("	targetSha: %#v,\n", tn.targetSha)
-	fmt.Printf("	dists: [%d][]NodeID{\n", len(tn.dists))
-	for ld, ns := range &tn.dists {
-		if len(ns) == 0 {
-			continue
-		}
-		fmt.Printf("		%d: []NodeID{\n", ld)
-		for _, n := range ns {
-			fmt.Printf("			MustHexID(\"%x\"),\n", n[:])
-		}
-		fmt.Println("		},")
-	}
-	fmt.Println("	},")
-	fmt.Println("}")
-}
-
 func injectResponse(net *Network, from *Node, ev nodeEvent, packet interface{}) {
 	go net.reqReadPacket(ingressPacket{remoteID: from.ID, remoteAddr: from.addr(), ev: ev, data: packet})
 }

p2p/discv5/node.go

@@ -66,23 +66,6 @@ func (n *Node) addr() *net.UDPAddr {
 	return &net.UDPAddr{IP: n.IP, Port: int(n.UDP)}
 }
 
-func (n *Node) setAddr(a *net.UDPAddr) {
-	n.IP = a.IP
-	if ipv4 := a.IP.To4(); ipv4 != nil {
-		n.IP = ipv4
-	}
-	n.UDP = uint16(a.Port)
-}
-
-// compares the given address against the stored values.
-func (n *Node) addrEqual(a *net.UDPAddr) bool {
-	ip := a.IP
-	if ipv4 := a.IP.To4(); ipv4 != nil {
-		ip = ipv4
-	}
-	return n.UDP == uint16(a.Port) && n.IP.Equal(ip)
-}
-
 // Incomplete returns true for nodes with no IP address.
 func (n *Node) Incomplete() bool {
 	return n.IP == nil
@@ -326,14 +309,6 @@ func (n NodeID) Pubkey() (*ecdsa.PublicKey, error) {
 	return p, nil
 }
 
-func (id NodeID) mustPubkey() ecdsa.PublicKey {
-	pk, err := id.Pubkey()
-	if err != nil {
-		panic(err)
-	}
-	return *pk
-}
-
 // recoverNodeID computes the public key used to sign the
 // given hash from the signature.
 func recoverNodeID(hash, sig []byte) (id NodeID, err error) {

p2p/discv5/ntp.go

-// Copyright 2016 The go-ethereum Authors
-// This file is part of the go-ethereum library.
-//
-// The go-ethereum library is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Lesser General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// The go-ethereum library is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU Lesser General Public License for more details.
-//
-// You should have received a copy of the GNU Lesser General Public License
-// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
-
-// Contains the NTP time drift detection via the SNTP protocol:
-//   https://tools.ietf.org/html/rfc4330
-
-package discv5
-
-import (
-	"fmt"
-	"net"
-	"sort"
-	"strings"
-	"time"
-
-	"github.com/ethereum/go-ethereum/log"
-)
-
-const (
-	ntpPool   = "pool.ntp.org" // ntpPool is the NTP server to query for the current time
-	ntpChecks = 3              // Number of measurements to do against the NTP server
-)
-
-// durationSlice attaches the methods of sort.Interface to []time.Duration,
-// sorting in increasing order.
-type durationSlice []time.Duration
-
-func (s durationSlice) Len() int           { return len(s) }
-func (s durationSlice) Less(i, j int) bool { return s[i] < s[j] }
-func (s durationSlice) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }
-
-// checkClockDrift queries an NTP server for clock drifts and warns the user if
-// one large enough is detected.
-func checkClockDrift() {
-	drift, err := sntpDrift(ntpChecks)
-	if err != nil {
-		return
-	}
-	if drift < -driftThreshold || drift > driftThreshold {
-		warning := fmt.Sprintf("System clock seems off by %v, which can prevent network connectivity", drift)
-		howtofix := fmt.Sprintf("Please enable network time synchronisation in system settings")
-		separator := strings.Repeat("-", len(warning))
-
-		log.Warn(separator)
-		log.Warn(warning)
-		log.Warn(howtofix)
-		log.Warn(separator)
-	} else {
-		log.Debug(fmt.Sprintf("Sanity NTP check reported %v drift, all ok", drift))
-	}
-}
-
-// sntpDrift does a naive time resolution against an NTP server and returns the
-// measured drift. This method uses the simple version of NTP. It's not precise
-// but should be fine for these purposes.
-//
-// Note, it executes two extra measurements compared to the number of requested
-// ones to be able to discard the two extremes as outliers.
-func sntpDrift(measurements int) (time.Duration, error) {
-	// Resolve the address of the NTP server
-	addr, err := net.ResolveUDPAddr("udp", ntpPool+":123")
-	if err != nil {
-		return 0, err
-	}
-	// Construct the time request (empty package with only 2 fields set):
-	//   Bits 3-5: Protocol version, 3
-	//   Bits 6-8: Mode of operation, client, 3
-	request := make([]byte, 48)
-	request[0] = 3<<3 | 3
-
-	// Execute each of the measurements
-	drifts := []time.Duration{}
-	for i := 0; i < measurements+2; i++ {
-		// Dial the NTP server and send the time retrieval request
-		conn, err := net.DialUDP("udp", nil, addr)
-		if err != nil {
-			return 0, err
-		}
-		defer conn.Close()
-
-		sent := time.Now()
-		if _, err = conn.Write(request); err != nil {
-			return 0, err
-		}
-		// Retrieve the reply and calculate the elapsed time
-		conn.SetDeadline(time.Now().Add(5 * time.Second))
-
-		reply := make([]byte, 48)
-		if _, err = conn.Read(reply); err != nil {
-			return 0, err
-		}
-		elapsed := time.Since(sent)
-
-		// Reconstruct the time from the reply data
-		sec := uint64(reply[43]) | uint64(reply[42])<<8 | uint64(reply[41])<<16 | uint64(reply[40])<<24
-		frac := uint64(reply[47]) | uint64(reply[46])<<8 | uint64(reply[45])<<16 | uint64(reply[44])<<24
-
-		nanosec := sec*1e9 + (frac*1e9)>>32
-
-		t := time.Date(1900, 1, 1, 0, 0, 0, 0, time.UTC).Add(time.Duration(nanosec)).Local()
-
-		// Calculate the drift based on an assumed answer time of RRT/2
-		drifts = append(drifts, sent.Sub(t)+elapsed/2)
-	}
-	// Calculate average drif (drop two extremities to avoid outliers)
-	sort.Sort(durationSlice(drifts))
-
-	drift := time.Duration(0)
-	for i := 1; i < len(drifts)-1; i++ {
-		drift += drifts[i]
-	}
-	return drift / time.Duration(measurements), nil
-}

p2p/discv5/sim_test.go

@@ -294,15 +294,6 @@ func (s *simulation) launchNode(log bool) *Network {
 	return net
 }
 
-func (s *simulation) dropNode(id NodeID) {
-	s.mu.Lock()
-	n := s.nodes[id]
-	delete(s.nodes, id)
-	s.mu.Unlock()
-
-	n.Close()
-}
-
 type simTransport struct {
 	joinTime   time.Time
 	sender     NodeID
@@ -358,22 +349,6 @@ func (st *simTransport) sendPing(remote *Node, remoteAddr *net.UDPAddr, topics [
 	return hash
 }
 
-func (st *simTransport) sendPong(remote *Node, pingHash []byte) {
-	raddr := remote.addr()
-
-	st.sendPacket(remote.ID, ingressPacket{
-		remoteID:   st.sender,
-		remoteAddr: st.senderAddr,
-		hash:       st.nextHash(),
-		ev:         pongPacket,
-		data: &pong{
-			To:         rpcEndpoint{IP: raddr.IP, UDP: uint16(raddr.Port), TCP: 30303},
-			ReplyTok:   pingHash,
-			Expiration: uint64(time.Now().Unix() + int64(expiration)),
-		},
-	})
-}
-
 func (st *simTransport) sendFindnodeHash(remote *Node, target common.Hash) {
 	st.sendPacket(remote.ID, ingressPacket{
 		remoteID:   st.sender,

p2p/discv5/table.go

@@ -14,12 +14,8 @@
 // You should have received a copy of the GNU Lesser General Public License
 // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
 
-// Package discv5 implements the RLPx v5 Topic Discovery Protocol.
-//
-// The Topic Discovery protocol provides a way to find RLPx nodes that
-// can be connected to. It uses a Kademlia-like protocol to maintain a
-// distributed database of the IDs and endpoints of all listening
-// nodes.
+// Package discv5 is a prototype implementation of Discvery v5.
+// Deprecated: do not use this package.
 package discv5
 
 import (

p2p/discv5/table_test.go

@@ -31,72 +31,6 @@ import (
 	"github.com/ethereum/go-ethereum/crypto"
 )
 
-type nullTransport struct{}
-
-func (nullTransport) sendPing(remote *Node, remoteAddr *net.UDPAddr) []byte { return []byte{1} }
-func (nullTransport) sendPong(remote *Node, pingHash []byte)                {}
-func (nullTransport) sendFindnode(remote *Node, target NodeID)              {}
-func (nullTransport) sendNeighbours(remote *Node, nodes []*Node)            {}
-func (nullTransport) localAddr() *net.UDPAddr                               { return new(net.UDPAddr) }
-func (nullTransport) Close()                                                {}
-
-// func TestTable_pingReplace(t *testing.T) {
-// 	doit := func(newNodeIsResponding, lastInBucketIsResponding bool) {
-// 		transport := newPingRecorder()
-// 		tab, _ := newTable(transport, NodeID{}, &net.UDPAddr{})
-// 		defer tab.Close()
-// 		pingSender := NewNode(MustHexID("a502af0f59b2aab7746995408c79e9ca312d2793cc997e44fc55eda62f0150bbb8c59a6f9269ba3a081518b62699ee807c7c19c20125ddfccca872608af9e370"), net.IP{}, 99, 99)
-//
-// 		// fill up the sender's bucket.
-// 		last := fillBucket(tab, 253)
-//
-// 		// this call to bond should replace the last node
-// 		// in its bucket if the node is not responding.
-// 		transport.responding[last.ID] = lastInBucketIsResponding
-// 		transport.responding[pingSender.ID] = newNodeIsResponding
-// 		tab.bond(true, pingSender.ID, &net.UDPAddr{}, 0)
-//
-// 		// first ping goes to sender (bonding pingback)
-// 		if !transport.pinged[pingSender.ID] {
-// 			t.Error("table did not ping back sender")
-// 		}
-// 		if newNodeIsResponding {
-// 			// second ping goes to oldest node in bucket
-// 			// to see whether it is still alive.
-// 			if !transport.pinged[last.ID] {
-// 				t.Error("table did not ping last node in bucket")
-// 			}
-// 		}
-//
-// 		tab.mutex.Lock()
-// 		defer tab.mutex.Unlock()
-// 		if l := len(tab.buckets[253].entries); l != bucketSize {
-// 			t.Errorf("wrong bucket size after bond: got %d, want %d", l, bucketSize)
-// 		}
-//
-// 		if lastInBucketIsResponding || !newNodeIsResponding {
-// 			if !contains(tab.buckets[253].entries, last.ID) {
-// 				t.Error("last entry was removed")
-// 			}
-// 			if contains(tab.buckets[253].entries, pingSender.ID) {
-// 				t.Error("new entry was added")
-// 			}
-// 		} else {
-// 			if contains(tab.buckets[253].entries, last.ID) {
-// 				t.Error("last entry was not removed")
-// 			}
-// 			if !contains(tab.buckets[253].entries, pingSender.ID) {
-// 				t.Error("new entry was not added")
-// 			}
-// 		}
-// 	}
-//
-// 	doit(true, true)
-// 	doit(false, true)
-// 	doit(true, false)
-// 	doit(false, false)
-// }
-
 func TestBucket_bumpNoDuplicates(t *testing.T) {
 	t.Parallel()
 	cfg := &quick.Config{
@@ -139,17 +73,6 @@ func TestBucket_bumpNoDuplicates(t *testing.T) {
 	}
 }
 
-// fillBucket inserts nodes into the given bucket until
-// it is full. The node's IDs dont correspond to their
-// hashes.
-func fillBucket(tab *Table, ld int) (last *Node) {
-	b := tab.buckets[ld]
-	for len(b.entries) < bucketSize {
-		b.entries = append(b.entries, nodeAtDistance(tab.self.sha, ld))
-	}
-	return b.entries[bucketSize-1]
-}
-
 // nodeAtDistance creates a node for which logdist(base, n.sha) == ld.
 // The node's ID does not correspond to n.sha.
 func nodeAtDistance(base common.Hash, ld int) (n *Node) {
@@ -159,28 +82,6 @@ func nodeAtDistance(base common.Hash, ld int) (n *Node) {
 	return n
 }
 
-type pingRecorder struct{ responding, pinged map[NodeID]bool }
-
-func newPingRecorder() *pingRecorder {
-	return &pingRecorder{make(map[NodeID]bool), make(map[NodeID]bool)}
-}
-
-func (t *pingRecorder) findnode(toid NodeID, toaddr *net.UDPAddr, target NodeID) ([]*Node, error) {
-	panic("findnode called on pingRecorder")
-}
-func (t *pingRecorder) close() {}
-func (t *pingRecorder) waitping(from NodeID) error {
-	return nil // remote always pings
-}
-func (t *pingRecorder) ping(toid NodeID, toaddr *net.UDPAddr) error {
-	t.pinged[toid] = true
-	if t.responding[toid] {
-		return nil
-	} else {
-		return errTimeout
-	}
-}
-
 func TestTable_closest(t *testing.T) {
 	t.Parallel()
 

p2p/discv5/ticket.go

@@ -22,7 +22,6 @@ import (
 	"fmt"
 	"math"
 	"math/rand"
-	"sort"
 	"time"
 
 	"github.com/ethereum/go-ethereum/common"
@@ -33,8 +32,6 @@ import (
 
 const (
 	ticketTimeBucketLen = time.Minute
-	timeWindow          = 10 // * ticketTimeBucketLen
-	wantTicketsInWindow = 10
 	collectFrequency    = time.Second * 30
 	registerFrequency   = time.Second * 60
 	maxCollectDebt      = 10
@@ -139,7 +136,6 @@ type ticketStore struct {
 
 	lastBucketFetched timeBucket
 	nextTicketCached  *ticketRef
-	nextTicketReg     mclock.AbsTime
 
 	searchTopicMap        map[Topic]searchTopic
 	nextTopicQueryCleanup mclock.AbsTime
@@ -268,57 +264,6 @@ func (s *ticketStore) nextSearchLookup(topic Topic) lookupInfo {
 	return target
 }
 
-// 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
-	}
-	// Gather all the tickers in the next time window
-	var tickets []ticketRef
-
-	buckets := s.tickets[topic].buckets
-	for idx := timeBucket(0); idx < timeWindow; idx++ {
-		tickets = append(tickets, buckets[s.lastBucketFetched+idx]...)
-	}
-	log.Trace("Retrieved discovery registration tickets", "topic", topic, "from", s.lastBucketFetched, "tickets", len(tickets))
-	return tickets
-}
-
-func (s *ticketStore) removeExcessTickets(t Topic) {
-	tickets := s.ticketsInWindow(t)
-	if len(tickets) <= wantTicketsInWindow {
-		return
-	}
-	sort.Sort(ticketRefByWaitTime(tickets))
-	for _, r := range tickets[wantTicketsInWindow:] {
-		s.removeTicketRef(r)
-	}
-}
-
-type ticketRefByWaitTime []ticketRef
-
-// Len is the number of elements in the collection.
-func (s ticketRefByWaitTime) Len() int {
-	return len(s)
-}
-
-func (ref ticketRef) waitTime() mclock.AbsTime {
-	return ref.t.regTime[ref.idx] - ref.t.issueTime
-}
-
-// Less reports whether the element with
-// index i should sort before the element with index j.
-func (s ticketRefByWaitTime) Less(i, j int) bool {
-	return s[i].waitTime() < s[j].waitTime()
-}
-
-// Swap swaps the elements with indexes i and j.
-func (s ticketRefByWaitTime) Swap(i, j int) {
-	s[i], s[j] = s[j], s[i]
-}
-
 func (s *ticketStore) addTicketRef(r ticketRef) {
 	topic := r.t.topics[r.idx]
 	tickets := s.tickets[topic]
@@ -565,15 +510,6 @@ func (s *ticketStore) addTicket(localTime mclock.AbsTime, pingHash []byte, ticke
 	}
 }
 
-func (s *ticketStore) getNodeTicket(node *Node) *ticket {
-	if s.nodes[node] == nil {
-		log.Trace("Retrieving node ticket", "node", node.ID, "serial", nil)
-	} else {
-		log.Trace("Retrieving node ticket", "node", node.ID, "serial", s.nodes[node].serial)
-	}
-	return s.nodes[node]
-}
-
 func (s *ticketStore) canQueryTopic(node *Node, topic Topic) bool {
 	qq := s.queriesSent[node]
 	if qq != nil {
@@ -770,12 +706,6 @@ func globalRandRead(b []byte) {
 	}
 }
 
-func (r *topicRadius) isInRadius(addrHash common.Hash) bool {
-	nodePrefix := binary.BigEndian.Uint64(addrHash[0:8])
-	dist := nodePrefix ^ r.topicHashPrefix
-	return dist < r.radius
-}
-
 func (r *topicRadius) chooseLookupBucket(a, b int) int {
 	if a < 0 {
 		a = 0

p2p/discv5/udp.go

@@ -27,7 +27,6 @@ import (
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/log"
-	"github.com/ethereum/go-ethereum/p2p/nat"
 	"github.com/ethereum/go-ethereum/p2p/netutil"
 	"github.com/ethereum/go-ethereum/rlp"
 )
@@ -38,15 +37,12 @@ const Version = 4
 var (
 	errPacketTooSmall = errors.New("too small")
 	errBadPrefix      = errors.New("bad prefix")
-	errTimeout        = errors.New("RPC timeout")
 )
 
 // Timeouts
 const (
 	respTimeout = 500 * time.Millisecond
 	expiration  = 20 * time.Second
-
-	driftThreshold = 10 * time.Second // Allowed clock drift before warning user
 )
 
 // RPC request structures
@@ -187,10 +183,6 @@ func makeEndpoint(addr *net.UDPAddr, tcpPort uint16) rpcEndpoint {
 	return rpcEndpoint{IP: ip, UDP: uint16(addr.Port), TCP: tcpPort}
 }
 
-func (e1 rpcEndpoint) equal(e2 rpcEndpoint) bool {
-	return e1.UDP == e2.UDP && e1.TCP == e2.TCP && e1.IP.Equal(e2.IP)
-}
-
 func nodeFromRPC(sender *net.UDPAddr, rn rpcNode) (*Node, error) {
 	if err := netutil.CheckRelayIP(sender.IP, rn.IP); err != nil {
 		return nil, err
@@ -225,7 +217,6 @@ type udp struct {
 	conn        conn
 	priv        *ecdsa.PrivateKey
 	ourEndpoint rpcEndpoint
-	nat         nat.Interface
 	net         *Network
 }
 
@@ -274,13 +265,6 @@ func (t *udp) sendPing(remote *Node, toaddr *net.UDPAddr, topics []Topic) (hash
 	return hash
 }
 
-func (t *udp) sendFindnode(remote *Node, target NodeID) {
-	t.sendPacket(remote.ID, remote.addr(), byte(findnodePacket), findnode{
-		Target:     target,
-		Expiration: uint64(time.Now().Add(expiration).Unix()),
-	})
-}
-
 func (t *udp) sendNeighbours(remote *Node, results []*Node) {
 	// Send neighbors in chunks with at most maxNeighbors per packet
 	// to stay below the 1280 byte limit.