plugeth/p2p/discover/udp.go
Felix Lange 30cd5c1854
all: new p2p node representation (#17643)
Package p2p/enode provides a generalized representation of p2p nodes
which can contain arbitrary information in key/value pairs. It is also
the new home for the node database. The "v4" identity scheme is also
moved here from p2p/enr to remove the dependency on Ethereum crypto from
that package.

Record signature handling is changed significantly. The identity scheme
registry is removed and acceptable schemes must be passed to any method
that needs identity. This means records must now be validated explicitly
after decoding.

The enode API is designed to make signature handling easy and safe: most
APIs around the codebase work with enode.Node, which is a wrapper around
a valid record. Going from enr.Record to enode.Node requires a valid
signature.

* p2p/discover: port to p2p/enode

This ports the discovery code to the new node representation in
p2p/enode. The wire protocol is unchanged, this can be considered a
refactoring change. The Kademlia table can now deal with nodes using an
arbitrary identity scheme. This requires a few incompatible API changes:

  - Table.Lookup is not available anymore. It used to take a public key
    as argument because v4 protocol requires one. Its replacement is
    LookupRandom.
  - Table.Resolve takes *enode.Node instead of NodeID. This is also for
    v4 protocol compatibility because nodes cannot be looked up by ID
    alone.
  - Types Node and NodeID are gone. Further commits in the series will be
    fixes all over the the codebase to deal with those removals.

* p2p: port to p2p/enode and discovery changes

This adapts package p2p to the changes in p2p/discover. All uses of
discover.Node and discover.NodeID are replaced by their equivalents from
p2p/enode.

New API is added to retrieve the enode.Node instance of a peer. The
behavior of Server.Self with discovery disabled is improved. It now
tries much harder to report a working IP address, falling back to
127.0.0.1 if no suitable address can be determined through other means.
These changes were needed for tests of other packages later in the
series.

* p2p/simulations, p2p/testing: port to p2p/enode

No surprises here, mostly replacements of discover.Node, discover.NodeID
with their new equivalents. The 'interesting' API changes are:

 - testing.ProtocolSession tracks complete nodes, not just their IDs.
 - adapters.NodeConfig has a new method to create a complete node.

These changes were needed to make swarm tests work.

Note that the NodeID change makes the code incompatible with old
simulation snapshots.

* whisper/whisperv5, whisper/whisperv6: port to p2p/enode

This port was easy because whisper uses []byte for node IDs and
URL strings in the API.

* eth: port to p2p/enode

Again, easy to port because eth uses strings for node IDs and doesn't
care about node information in any way.

* les: port to p2p/enode

Apart from replacing discover.NodeID with enode.ID, most changes are in
the server pool code. It now deals with complete nodes instead
of (Pubkey, IP, Port) triples. The database format is unchanged for now,
but we should probably change it to use the node database later.

* node: port to p2p/enode

This change simply replaces discover.Node and discover.NodeID with their
new equivalents.

* swarm/network: port to p2p/enode

Swarm has its own node address representation, BzzAddr, containing both
an overlay address (the hash of a secp256k1 public key) and an underlay
address (enode:// URL).

There are no changes to the BzzAddr format in this commit, but certain
operations such as creating a BzzAddr from a node ID are now impossible
because node IDs aren't public keys anymore.

Most swarm-related changes in the series remove uses of
NewAddrFromNodeID, replacing it with NewAddr which takes a complete node
as argument. ToOverlayAddr is removed because we can just use the node
ID directly.
2018-09-25 00:59:00 +02:00

712 lines
20 KiB
Go

// Copyright 2015 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/>.
package discover
import (
"bytes"
"container/list"
"crypto/ecdsa"
"errors"
"fmt"
"net"
"time"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/log"
"github.com/ethereum/go-ethereum/p2p/enode"
"github.com/ethereum/go-ethereum/p2p/nat"
"github.com/ethereum/go-ethereum/p2p/netutil"
"github.com/ethereum/go-ethereum/rlp"
)
// Errors
var (
errPacketTooSmall = errors.New("too small")
errBadHash = errors.New("bad hash")
errExpired = errors.New("expired")
errUnsolicitedReply = errors.New("unsolicited reply")
errUnknownNode = errors.New("unknown node")
errTimeout = errors.New("RPC timeout")
errClockWarp = errors.New("reply deadline too far in the future")
errClosed = errors.New("socket closed")
)
// Timeouts
const (
respTimeout = 500 * time.Millisecond
expiration = 20 * time.Second
bondExpiration = 24 * time.Hour
ntpFailureThreshold = 32 // Continuous timeouts after which to check NTP
ntpWarningCooldown = 10 * time.Minute // Minimum amount of time to pass before repeating NTP warning
driftThreshold = 10 * time.Second // Allowed clock drift before warning user
)
// RPC packet types
const (
pingPacket = iota + 1 // zero is 'reserved'
pongPacket
findnodePacket
neighborsPacket
)
// RPC request structures
type (
ping struct {
Version uint
From, To rpcEndpoint
Expiration uint64
// Ignore additional fields (for forward compatibility).
Rest []rlp.RawValue `rlp:"tail"`
}
// pong is the reply to ping.
pong struct {
// This field should mirror the UDP envelope address
// of the ping packet, which provides a way to discover the
// the external address (after NAT).
To rpcEndpoint
ReplyTok []byte // This contains the hash of the ping packet.
Expiration uint64 // Absolute timestamp at which the packet becomes invalid.
// Ignore additional fields (for forward compatibility).
Rest []rlp.RawValue `rlp:"tail"`
}
// findnode is a query for nodes close to the given target.
findnode struct {
Target encPubkey
Expiration uint64
// Ignore additional fields (for forward compatibility).
Rest []rlp.RawValue `rlp:"tail"`
}
// reply to findnode
neighbors struct {
Nodes []rpcNode
Expiration uint64
// Ignore additional fields (for forward compatibility).
Rest []rlp.RawValue `rlp:"tail"`
}
rpcNode struct {
IP net.IP // len 4 for IPv4 or 16 for IPv6
UDP uint16 // for discovery protocol
TCP uint16 // for RLPx protocol
ID encPubkey
}
rpcEndpoint struct {
IP net.IP // len 4 for IPv4 or 16 for IPv6
UDP uint16 // for discovery protocol
TCP uint16 // for RLPx protocol
}
)
func makeEndpoint(addr *net.UDPAddr, tcpPort uint16) rpcEndpoint {
ip := addr.IP.To4()
if ip == nil {
ip = addr.IP.To16()
}
return rpcEndpoint{IP: ip, UDP: uint16(addr.Port), TCP: tcpPort}
}
func (t *udp) nodeFromRPC(sender *net.UDPAddr, rn rpcNode) (*node, error) {
if rn.UDP <= 1024 {
return nil, errors.New("low port")
}
if err := netutil.CheckRelayIP(sender.IP, rn.IP); err != nil {
return nil, err
}
if t.netrestrict != nil && !t.netrestrict.Contains(rn.IP) {
return nil, errors.New("not contained in netrestrict whitelist")
}
key, err := decodePubkey(rn.ID)
if err != nil {
return nil, err
}
n := wrapNode(enode.NewV4(key, rn.IP, int(rn.TCP), int(rn.UDP)))
err = n.ValidateComplete()
return n, err
}
func nodeToRPC(n *node) rpcNode {
var key ecdsa.PublicKey
var ekey encPubkey
if err := n.Load((*enode.Secp256k1)(&key)); err == nil {
ekey = encodePubkey(&key)
}
return rpcNode{ID: ekey, IP: n.IP(), UDP: uint16(n.UDP()), TCP: uint16(n.TCP())}
}
type packet interface {
handle(t *udp, from *net.UDPAddr, fromKey encPubkey, mac []byte) error
name() string
}
type conn interface {
ReadFromUDP(b []byte) (n int, addr *net.UDPAddr, err error)
WriteToUDP(b []byte, addr *net.UDPAddr) (n int, err error)
Close() error
LocalAddr() net.Addr
}
// udp implements the RPC protocol.
type udp struct {
conn conn
netrestrict *netutil.Netlist
priv *ecdsa.PrivateKey
ourEndpoint rpcEndpoint
addpending chan *pending
gotreply chan reply
closing chan struct{}
nat nat.Interface
*Table
}
// pending represents a pending reply.
//
// some implementations of the protocol wish to send more than one
// reply packet to findnode. in general, any neighbors packet cannot
// be matched up with a specific findnode packet.
//
// our implementation handles this by storing a callback function for
// each pending reply. incoming packets from a node are dispatched
// to all the callback functions for that node.
type pending struct {
// these fields must match in the reply.
from enode.ID
ptype byte
// time when the request must complete
deadline time.Time
// callback is called when a matching reply arrives. if it returns
// true, the callback is removed from the pending reply queue.
// if it returns false, the reply is considered incomplete and
// the callback will be invoked again for the next matching reply.
callback func(resp interface{}) (done bool)
// errc receives nil when the callback indicates completion or an
// error if no further reply is received within the timeout.
errc chan<- error
}
type reply struct {
from enode.ID
ptype byte
data interface{}
// loop indicates whether there was
// a matching request by sending on this channel.
matched chan<- bool
}
// ReadPacket is sent to the unhandled channel when it could not be processed
type ReadPacket struct {
Data []byte
Addr *net.UDPAddr
}
// Config holds Table-related settings.
type Config struct {
// These settings are required and configure the UDP listener:
PrivateKey *ecdsa.PrivateKey
// These settings are optional:
AnnounceAddr *net.UDPAddr // local address announced in the DHT
NodeDBPath string // if set, the node database is stored at this filesystem location
NetRestrict *netutil.Netlist // network whitelist
Bootnodes []*enode.Node // list of bootstrap nodes
Unhandled chan<- ReadPacket // unhandled packets are sent on this channel
}
// ListenUDP returns a new table that listens for UDP packets on laddr.
func ListenUDP(c conn, cfg Config) (*Table, error) {
tab, _, err := newUDP(c, cfg)
if err != nil {
return nil, err
}
log.Info("UDP listener up", "self", tab.self)
return tab, nil
}
func newUDP(c conn, cfg Config) (*Table, *udp, error) {
realaddr := c.LocalAddr().(*net.UDPAddr)
if cfg.AnnounceAddr != nil {
realaddr = cfg.AnnounceAddr
}
self := enode.NewV4(&cfg.PrivateKey.PublicKey, realaddr.IP, realaddr.Port, realaddr.Port)
db, err := enode.OpenDB(cfg.NodeDBPath)
if err != nil {
return nil, nil, err
}
udp := &udp{
conn: c,
priv: cfg.PrivateKey,
netrestrict: cfg.NetRestrict,
closing: make(chan struct{}),
gotreply: make(chan reply),
addpending: make(chan *pending),
}
// TODO: separate TCP port
udp.ourEndpoint = makeEndpoint(realaddr, uint16(realaddr.Port))
tab, err := newTable(udp, self, db, cfg.Bootnodes)
if err != nil {
return nil, nil, err
}
udp.Table = tab
go udp.loop()
go udp.readLoop(cfg.Unhandled)
return udp.Table, udp, nil
}
func (t *udp) close() {
close(t.closing)
t.conn.Close()
t.db.Close()
// TODO: wait for the loops to end.
}
// ping sends a ping message to the given node and waits for a reply.
func (t *udp) ping(toid enode.ID, toaddr *net.UDPAddr) error {
return <-t.sendPing(toid, toaddr, nil)
}
// sendPing sends a ping message to the given node and invokes the callback
// when the reply arrives.
func (t *udp) sendPing(toid enode.ID, toaddr *net.UDPAddr, callback func()) <-chan error {
req := &ping{
Version: 4,
From: t.ourEndpoint,
To: makeEndpoint(toaddr, 0), // TODO: maybe use known TCP port from DB
Expiration: uint64(time.Now().Add(expiration).Unix()),
}
packet, hash, err := encodePacket(t.priv, pingPacket, req)
if err != nil {
errc := make(chan error, 1)
errc <- err
return errc
}
errc := t.pending(toid, pongPacket, func(p interface{}) bool {
ok := bytes.Equal(p.(*pong).ReplyTok, hash)
if ok && callback != nil {
callback()
}
return ok
})
t.write(toaddr, req.name(), packet)
return errc
}
func (t *udp) waitping(from enode.ID) error {
return <-t.pending(from, pingPacket, func(interface{}) bool { return true })
}
// findnode sends a findnode request to the given node and waits until
// the node has sent up to k neighbors.
func (t *udp) findnode(toid enode.ID, toaddr *net.UDPAddr, target encPubkey) ([]*node, error) {
// If we haven't seen a ping from the destination node for a while, it won't remember
// our endpoint proof and reject findnode. Solicit a ping first.
if time.Since(t.db.LastPingReceived(toid)) > bondExpiration {
t.ping(toid, toaddr)
t.waitping(toid)
}
nodes := make([]*node, 0, bucketSize)
nreceived := 0
errc := t.pending(toid, neighborsPacket, func(r interface{}) bool {
reply := r.(*neighbors)
for _, rn := range reply.Nodes {
nreceived++
n, err := t.nodeFromRPC(toaddr, rn)
if err != nil {
log.Trace("Invalid neighbor node received", "ip", rn.IP, "addr", toaddr, "err", err)
continue
}
nodes = append(nodes, n)
}
return nreceived >= bucketSize
})
t.send(toaddr, findnodePacket, &findnode{
Target: target,
Expiration: uint64(time.Now().Add(expiration).Unix()),
})
return nodes, <-errc
}
// pending adds a reply callback to the pending reply queue.
// see the documentation of type pending for a detailed explanation.
func (t *udp) pending(id enode.ID, ptype byte, callback func(interface{}) bool) <-chan error {
ch := make(chan error, 1)
p := &pending{from: id, ptype: ptype, callback: callback, errc: ch}
select {
case t.addpending <- p:
// loop will handle it
case <-t.closing:
ch <- errClosed
}
return ch
}
func (t *udp) handleReply(from enode.ID, ptype byte, req packet) bool {
matched := make(chan bool, 1)
select {
case t.gotreply <- reply{from, ptype, req, matched}:
// loop will handle it
return <-matched
case <-t.closing:
return false
}
}
// loop runs in its own goroutine. it keeps track of
// the refresh timer and the pending reply queue.
func (t *udp) loop() {
var (
plist = list.New()
timeout = time.NewTimer(0)
nextTimeout *pending // head of plist when timeout was last reset
contTimeouts = 0 // number of continuous timeouts to do NTP checks
ntpWarnTime = time.Unix(0, 0)
)
<-timeout.C // ignore first timeout
defer timeout.Stop()
resetTimeout := func() {
if plist.Front() == nil || nextTimeout == plist.Front().Value {
return
}
// Start the timer so it fires when the next pending reply has expired.
now := time.Now()
for el := plist.Front(); el != nil; el = el.Next() {
nextTimeout = el.Value.(*pending)
if dist := nextTimeout.deadline.Sub(now); dist < 2*respTimeout {
timeout.Reset(dist)
return
}
// Remove pending replies whose deadline is too far in the
// future. These can occur if the system clock jumped
// backwards after the deadline was assigned.
nextTimeout.errc <- errClockWarp
plist.Remove(el)
}
nextTimeout = nil
timeout.Stop()
}
for {
resetTimeout()
select {
case <-t.closing:
for el := plist.Front(); el != nil; el = el.Next() {
el.Value.(*pending).errc <- errClosed
}
return
case p := <-t.addpending:
p.deadline = time.Now().Add(respTimeout)
plist.PushBack(p)
case r := <-t.gotreply:
var matched bool
for el := plist.Front(); el != nil; el = el.Next() {
p := el.Value.(*pending)
if p.from == r.from && p.ptype == r.ptype {
matched = true
// Remove the matcher if its callback indicates
// that all replies have been received. This is
// required for packet types that expect multiple
// reply packets.
if p.callback(r.data) {
p.errc <- nil
plist.Remove(el)
}
// Reset the continuous timeout counter (time drift detection)
contTimeouts = 0
}
}
r.matched <- matched
case now := <-timeout.C:
nextTimeout = nil
// Notify and remove callbacks whose deadline is in the past.
for el := plist.Front(); el != nil; el = el.Next() {
p := el.Value.(*pending)
if now.After(p.deadline) || now.Equal(p.deadline) {
p.errc <- errTimeout
plist.Remove(el)
contTimeouts++
}
}
// If we've accumulated too many timeouts, do an NTP time sync check
if contTimeouts > ntpFailureThreshold {
if time.Since(ntpWarnTime) >= ntpWarningCooldown {
ntpWarnTime = time.Now()
go checkClockDrift()
}
contTimeouts = 0
}
}
}
}
const (
macSize = 256 / 8
sigSize = 520 / 8
headSize = macSize + sigSize // space of packet frame data
)
var (
headSpace = make([]byte, headSize)
// Neighbors replies are sent across multiple packets to
// stay below the 1280 byte limit. We compute the maximum number
// of entries by stuffing a packet until it grows too large.
maxNeighbors int
)
func init() {
p := neighbors{Expiration: ^uint64(0)}
maxSizeNode := rpcNode{IP: make(net.IP, 16), UDP: ^uint16(0), TCP: ^uint16(0)}
for n := 0; ; n++ {
p.Nodes = append(p.Nodes, maxSizeNode)
size, _, err := rlp.EncodeToReader(p)
if err != nil {
// If this ever happens, it will be caught by the unit tests.
panic("cannot encode: " + err.Error())
}
if headSize+size+1 >= 1280 {
maxNeighbors = n
break
}
}
}
func (t *udp) send(toaddr *net.UDPAddr, ptype byte, req packet) ([]byte, error) {
packet, hash, err := encodePacket(t.priv, ptype, req)
if err != nil {
return hash, err
}
return hash, t.write(toaddr, req.name(), packet)
}
func (t *udp) write(toaddr *net.UDPAddr, what string, packet []byte) error {
_, err := t.conn.WriteToUDP(packet, toaddr)
log.Trace(">> "+what, "addr", toaddr, "err", err)
return err
}
func encodePacket(priv *ecdsa.PrivateKey, ptype byte, req interface{}) (packet, hash []byte, err error) {
b := new(bytes.Buffer)
b.Write(headSpace)
b.WriteByte(ptype)
if err := rlp.Encode(b, req); err != nil {
log.Error("Can't encode discv4 packet", "err", err)
return nil, nil, err
}
packet = b.Bytes()
sig, err := crypto.Sign(crypto.Keccak256(packet[headSize:]), priv)
if err != nil {
log.Error("Can't sign discv4 packet", "err", err)
return nil, nil, err
}
copy(packet[macSize:], sig)
// add the hash to the front. Note: this doesn't protect the
// packet in any way. Our public key will be part of this hash in
// The future.
hash = crypto.Keccak256(packet[macSize:])
copy(packet, hash)
return packet, hash, nil
}
// readLoop runs in its own goroutine. it handles incoming UDP packets.
func (t *udp) readLoop(unhandled chan<- ReadPacket) {
defer t.conn.Close()
if unhandled != nil {
defer close(unhandled)
}
// Discovery packets are defined to be no larger than 1280 bytes.
// Packets larger than this size will be cut at the end and treated
// as invalid because their hash won't match.
buf := make([]byte, 1280)
for {
nbytes, from, err := t.conn.ReadFromUDP(buf)
if netutil.IsTemporaryError(err) {
// Ignore temporary read errors.
log.Debug("Temporary UDP read error", "err", err)
continue
} else if err != nil {
// Shut down the loop for permament errors.
log.Debug("UDP read error", "err", err)
return
}
if t.handlePacket(from, buf[:nbytes]) != nil && unhandled != nil {
select {
case unhandled <- ReadPacket{buf[:nbytes], from}:
default:
}
}
}
}
func (t *udp) handlePacket(from *net.UDPAddr, buf []byte) error {
packet, fromID, hash, err := decodePacket(buf)
if err != nil {
log.Debug("Bad discv4 packet", "addr", from, "err", err)
return err
}
err = packet.handle(t, from, fromID, hash)
log.Trace("<< "+packet.name(), "addr", from, "err", err)
return err
}
func decodePacket(buf []byte) (packet, encPubkey, []byte, error) {
if len(buf) < headSize+1 {
return nil, encPubkey{}, nil, errPacketTooSmall
}
hash, sig, sigdata := buf[:macSize], buf[macSize:headSize], buf[headSize:]
shouldhash := crypto.Keccak256(buf[macSize:])
if !bytes.Equal(hash, shouldhash) {
return nil, encPubkey{}, nil, errBadHash
}
fromKey, err := recoverNodeKey(crypto.Keccak256(buf[headSize:]), sig)
if err != nil {
return nil, fromKey, hash, err
}
var req packet
switch ptype := sigdata[0]; ptype {
case pingPacket:
req = new(ping)
case pongPacket:
req = new(pong)
case findnodePacket:
req = new(findnode)
case neighborsPacket:
req = new(neighbors)
default:
return nil, fromKey, hash, fmt.Errorf("unknown type: %d", ptype)
}
s := rlp.NewStream(bytes.NewReader(sigdata[1:]), 0)
err = s.Decode(req)
return req, fromKey, hash, err
}
func (req *ping) handle(t *udp, from *net.UDPAddr, fromKey encPubkey, mac []byte) error {
if expired(req.Expiration) {
return errExpired
}
key, err := decodePubkey(fromKey)
if err != nil {
return fmt.Errorf("invalid public key: %v", err)
}
t.send(from, pongPacket, &pong{
To: makeEndpoint(from, req.From.TCP),
ReplyTok: mac,
Expiration: uint64(time.Now().Add(expiration).Unix()),
})
n := wrapNode(enode.NewV4(key, from.IP, int(req.From.TCP), from.Port))
t.handleReply(n.ID(), pingPacket, req)
if time.Since(t.db.LastPongReceived(n.ID())) > bondExpiration {
t.sendPing(n.ID(), from, func() { t.addThroughPing(n) })
} else {
t.addThroughPing(n)
}
t.db.UpdateLastPingReceived(n.ID(), time.Now())
return nil
}
func (req *ping) name() string { return "PING/v4" }
func (req *pong) handle(t *udp, from *net.UDPAddr, fromKey encPubkey, mac []byte) error {
if expired(req.Expiration) {
return errExpired
}
fromID := fromKey.id()
if !t.handleReply(fromID, pongPacket, req) {
return errUnsolicitedReply
}
t.db.UpdateLastPongReceived(fromID, time.Now())
return nil
}
func (req *pong) name() string { return "PONG/v4" }
func (req *findnode) handle(t *udp, from *net.UDPAddr, fromKey encPubkey, mac []byte) error {
if expired(req.Expiration) {
return errExpired
}
fromID := fromKey.id()
if time.Since(t.db.LastPongReceived(fromID)) > bondExpiration {
// No endpoint proof pong exists, we don't process the packet. This prevents an
// attack vector where the discovery protocol could be used to amplify traffic in a
// DDOS attack. A malicious actor would send a findnode request with the IP address
// and UDP port of the target as the source address. The recipient of the findnode
// packet would then send a neighbors packet (which is a much bigger packet than
// findnode) to the victim.
return errUnknownNode
}
target := enode.ID(crypto.Keccak256Hash(req.Target[:]))
t.mutex.Lock()
closest := t.closest(target, bucketSize).entries
t.mutex.Unlock()
p := neighbors{Expiration: uint64(time.Now().Add(expiration).Unix())}
var sent bool
// Send neighbors in chunks with at most maxNeighbors per packet
// to stay below the 1280 byte limit.
for _, n := range closest {
if netutil.CheckRelayIP(from.IP, n.IP()) == nil {
p.Nodes = append(p.Nodes, nodeToRPC(n))
}
if len(p.Nodes) == maxNeighbors {
t.send(from, neighborsPacket, &p)
p.Nodes = p.Nodes[:0]
sent = true
}
}
if len(p.Nodes) > 0 || !sent {
t.send(from, neighborsPacket, &p)
}
return nil
}
func (req *findnode) name() string { return "FINDNODE/v4" }
func (req *neighbors) handle(t *udp, from *net.UDPAddr, fromKey encPubkey, mac []byte) error {
if expired(req.Expiration) {
return errExpired
}
if !t.handleReply(fromKey.id(), neighborsPacket, req) {
return errUnsolicitedReply
}
return nil
}
func (req *neighbors) name() string { return "NEIGHBORS/v4" }
func expired(ts uint64) bool {
return time.Unix(int64(ts), 0).Before(time.Now())
}