plugeth/les/serverpool.go
Felix Lange e83c3ccc47
p2p/enode: improve IPv6 support, add ENR text representation (#19663)
* p2p/enr: add entries for for IPv4/IPv6 separation

This adds entry types for "ip6", "udp6", "tcp6" keys. The IP type stays
around because removing it would break a lot of code and force everyone
to care about the distinction.

* p2p/enode: track IPv4 and IPv6 address separately

LocalNode predicts the local node's UDP endpoint and updates the record.
This change makes it predict IPv4 and IPv6 endpoints separately since
they can now be in the record at the same time.

* p2p/enode: implement base64 text format
* all: switch to enode.Parse(...)

This allows passing base64-encoded node records to all the places that
previously accepted enode:// URLs. The URL format is still supported.

* cmd/bootnode, p2p: log node URL instead of ENR

...and return the base64 record in NodeInfo.
2019-06-07 15:31:00 +02:00

896 lines
27 KiB
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/>.
package les
import (
"crypto/ecdsa"
"fmt"
"io"
"math"
"math/rand"
"net"
"strconv"
"sync"
"time"
"github.com/ethereum/go-ethereum/common/mclock"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/ethdb"
"github.com/ethereum/go-ethereum/log"
"github.com/ethereum/go-ethereum/p2p"
"github.com/ethereum/go-ethereum/p2p/discv5"
"github.com/ethereum/go-ethereum/p2p/enode"
"github.com/ethereum/go-ethereum/rlp"
)
const (
// After a connection has been ended or timed out, there is a waiting period
// before it can be selected for connection again.
// waiting period = base delay * (1 + random(1))
// base delay = shortRetryDelay for the first shortRetryCnt times after a
// successful connection, after that longRetryDelay is applied
shortRetryCnt = 5
shortRetryDelay = time.Second * 5
longRetryDelay = time.Minute * 10
// maxNewEntries is the maximum number of newly discovered (never connected) nodes.
// If the limit is reached, the least recently discovered one is thrown out.
maxNewEntries = 1000
// maxKnownEntries is the maximum number of known (already connected) nodes.
// If the limit is reached, the least recently connected one is thrown out.
// (not that unlike new entries, known entries are persistent)
maxKnownEntries = 1000
// target for simultaneously connected servers
targetServerCount = 5
// target for servers selected from the known table
// (we leave room for trying new ones if there is any)
targetKnownSelect = 3
// after dialTimeout, consider the server unavailable and adjust statistics
dialTimeout = time.Second * 30
// targetConnTime is the minimum expected connection duration before a server
// drops a client without any specific reason
targetConnTime = time.Minute * 10
// new entry selection weight calculation based on most recent discovery time:
// unity until discoverExpireStart, then exponential decay with discoverExpireConst
discoverExpireStart = time.Minute * 20
discoverExpireConst = time.Minute * 20
// known entry selection weight is dropped by a factor of exp(-failDropLn) after
// each unsuccessful connection (restored after a successful one)
failDropLn = 0.1
// known node connection success and quality statistics have a long term average
// and a short term value which is adjusted exponentially with a factor of
// pstatRecentAdjust with each dial/connection and also returned exponentially
// to the average with the time constant pstatReturnToMeanTC
pstatReturnToMeanTC = time.Hour
// node address selection weight is dropped by a factor of exp(-addrFailDropLn) after
// each unsuccessful connection (restored after a successful one)
addrFailDropLn = math.Ln2
// responseScoreTC and delayScoreTC are exponential decay time constants for
// calculating selection chances from response times and block delay times
responseScoreTC = time.Millisecond * 100
delayScoreTC = time.Second * 5
timeoutPow = 10
// initStatsWeight is used to initialize previously unknown peers with good
// statistics to give a chance to prove themselves
initStatsWeight = 1
)
// connReq represents a request for peer connection.
type connReq struct {
p *peer
node *enode.Node
result chan *poolEntry
}
// disconnReq represents a request for peer disconnection.
type disconnReq struct {
entry *poolEntry
stopped bool
done chan struct{}
}
// registerReq represents a request for peer registration.
type registerReq struct {
entry *poolEntry
done chan struct{}
}
// serverPool implements a pool for storing and selecting newly discovered and already
// known light server nodes. It received discovered nodes, stores statistics about
// known nodes and takes care of always having enough good quality servers connected.
type serverPool struct {
db ethdb.Database
dbKey []byte
server *p2p.Server
quit chan struct{}
wg *sync.WaitGroup
connWg sync.WaitGroup
topic discv5.Topic
discSetPeriod chan time.Duration
discNodes chan *enode.Node
discLookups chan bool
trustedNodes map[enode.ID]*enode.Node
entries map[enode.ID]*poolEntry
timeout, enableRetry chan *poolEntry
adjustStats chan poolStatAdjust
knownQueue, newQueue poolEntryQueue
knownSelect, newSelect *weightedRandomSelect
knownSelected, newSelected int
fastDiscover bool
connCh chan *connReq
disconnCh chan *disconnReq
registerCh chan *registerReq
}
// newServerPool creates a new serverPool instance
func newServerPool(db ethdb.Database, quit chan struct{}, wg *sync.WaitGroup, trustedNodes []string) *serverPool {
pool := &serverPool{
db: db,
quit: quit,
wg: wg,
entries: make(map[enode.ID]*poolEntry),
timeout: make(chan *poolEntry, 1),
adjustStats: make(chan poolStatAdjust, 100),
enableRetry: make(chan *poolEntry, 1),
connCh: make(chan *connReq),
disconnCh: make(chan *disconnReq),
registerCh: make(chan *registerReq),
knownSelect: newWeightedRandomSelect(),
newSelect: newWeightedRandomSelect(),
fastDiscover: true,
trustedNodes: parseTrustedNodes(trustedNodes),
}
pool.knownQueue = newPoolEntryQueue(maxKnownEntries, pool.removeEntry)
pool.newQueue = newPoolEntryQueue(maxNewEntries, pool.removeEntry)
return pool
}
func (pool *serverPool) start(server *p2p.Server, topic discv5.Topic) {
pool.server = server
pool.topic = topic
pool.dbKey = append([]byte("serverPool/"), []byte(topic)...)
pool.wg.Add(1)
pool.loadNodes()
pool.connectToTrustedNodes()
if pool.server.DiscV5 != nil {
pool.discSetPeriod = make(chan time.Duration, 1)
pool.discNodes = make(chan *enode.Node, 100)
pool.discLookups = make(chan bool, 100)
go pool.discoverNodes()
}
pool.checkDial()
go pool.eventLoop()
}
// discoverNodes wraps SearchTopic, converting result nodes to enode.Node.
func (pool *serverPool) discoverNodes() {
ch := make(chan *discv5.Node)
go func() {
pool.server.DiscV5.SearchTopic(pool.topic, pool.discSetPeriod, ch, pool.discLookups)
close(ch)
}()
for n := range ch {
pubkey, err := decodePubkey64(n.ID[:])
if err != nil {
continue
}
pool.discNodes <- enode.NewV4(pubkey, n.IP, int(n.TCP), int(n.UDP))
}
}
// connect should be called upon any incoming connection. If the connection has been
// dialed by the server pool recently, the appropriate pool entry is returned.
// Otherwise, the connection should be rejected.
// Note that whenever a connection has been accepted and a pool entry has been returned,
// disconnect should also always be called.
func (pool *serverPool) connect(p *peer, node *enode.Node) *poolEntry {
log.Debug("Connect new entry", "enode", p.id)
req := &connReq{p: p, node: node, result: make(chan *poolEntry, 1)}
select {
case pool.connCh <- req:
case <-pool.quit:
return nil
}
return <-req.result
}
// registered should be called after a successful handshake
func (pool *serverPool) registered(entry *poolEntry) {
log.Debug("Registered new entry", "enode", entry.node.ID())
req := &registerReq{entry: entry, done: make(chan struct{})}
select {
case pool.registerCh <- req:
case <-pool.quit:
return
}
<-req.done
}
// disconnect should be called when ending a connection. Service quality statistics
// can be updated optionally (not updated if no registration happened, in this case
// only connection statistics are updated, just like in case of timeout)
func (pool *serverPool) disconnect(entry *poolEntry) {
stopped := false
select {
case <-pool.quit:
stopped = true
default:
}
log.Debug("Disconnected old entry", "enode", entry.node.ID())
req := &disconnReq{entry: entry, stopped: stopped, done: make(chan struct{})}
// Block until disconnection request is served.
pool.disconnCh <- req
<-req.done
}
const (
pseBlockDelay = iota
pseResponseTime
pseResponseTimeout
)
// poolStatAdjust records are sent to adjust peer block delay/response time statistics
type poolStatAdjust struct {
adjustType int
entry *poolEntry
time time.Duration
}
// adjustBlockDelay adjusts the block announce delay statistics of a node
func (pool *serverPool) adjustBlockDelay(entry *poolEntry, time time.Duration) {
if entry == nil {
return
}
pool.adjustStats <- poolStatAdjust{pseBlockDelay, entry, time}
}
// adjustResponseTime adjusts the request response time statistics of a node
func (pool *serverPool) adjustResponseTime(entry *poolEntry, time time.Duration, timeout bool) {
if entry == nil {
return
}
if timeout {
pool.adjustStats <- poolStatAdjust{pseResponseTimeout, entry, time}
} else {
pool.adjustStats <- poolStatAdjust{pseResponseTime, entry, time}
}
}
// eventLoop handles pool events and mutex locking for all internal functions
func (pool *serverPool) eventLoop() {
lookupCnt := 0
var convTime mclock.AbsTime
if pool.discSetPeriod != nil {
pool.discSetPeriod <- time.Millisecond * 100
}
// disconnect updates service quality statistics depending on the connection time
// and disconnection initiator.
disconnect := func(req *disconnReq, stopped bool) {
// Handle peer disconnection requests.
entry := req.entry
if entry.state == psRegistered {
connAdjust := float64(mclock.Now()-entry.regTime) / float64(targetConnTime)
if connAdjust > 1 {
connAdjust = 1
}
if stopped {
// disconnect requested by ourselves.
entry.connectStats.add(1, connAdjust)
} else {
// disconnect requested by server side.
entry.connectStats.add(connAdjust, 1)
}
}
entry.state = psNotConnected
if entry.knownSelected {
pool.knownSelected--
} else {
pool.newSelected--
}
pool.setRetryDial(entry)
pool.connWg.Done()
close(req.done)
}
for {
select {
case entry := <-pool.timeout:
if !entry.removed {
pool.checkDialTimeout(entry)
}
case entry := <-pool.enableRetry:
if !entry.removed {
entry.delayedRetry = false
pool.updateCheckDial(entry)
}
case adj := <-pool.adjustStats:
switch adj.adjustType {
case pseBlockDelay:
adj.entry.delayStats.add(float64(adj.time), 1)
case pseResponseTime:
adj.entry.responseStats.add(float64(adj.time), 1)
adj.entry.timeoutStats.add(0, 1)
case pseResponseTimeout:
adj.entry.timeoutStats.add(1, 1)
}
case node := <-pool.discNodes:
if pool.trustedNodes[node.ID()] == nil {
entry := pool.findOrNewNode(node)
pool.updateCheckDial(entry)
}
case conv := <-pool.discLookups:
if conv {
if lookupCnt == 0 {
convTime = mclock.Now()
}
lookupCnt++
if pool.fastDiscover && (lookupCnt == 50 || time.Duration(mclock.Now()-convTime) > time.Minute) {
pool.fastDiscover = false
if pool.discSetPeriod != nil {
pool.discSetPeriod <- time.Minute
}
}
}
case req := <-pool.connCh:
if pool.trustedNodes[req.p.ID()] != nil {
// ignore trusted nodes
req.result <- nil
} else {
// Handle peer connection requests.
entry := pool.entries[req.p.ID()]
if entry == nil {
entry = pool.findOrNewNode(req.node)
}
if entry.state == psConnected || entry.state == psRegistered {
req.result <- nil
continue
}
pool.connWg.Add(1)
entry.peer = req.p
entry.state = psConnected
addr := &poolEntryAddress{
ip: req.node.IP(),
port: uint16(req.node.TCP()),
lastSeen: mclock.Now(),
}
entry.lastConnected = addr
entry.addr = make(map[string]*poolEntryAddress)
entry.addr[addr.strKey()] = addr
entry.addrSelect = *newWeightedRandomSelect()
entry.addrSelect.update(addr)
req.result <- entry
}
case req := <-pool.registerCh:
// Handle peer registration requests.
entry := req.entry
entry.state = psRegistered
entry.regTime = mclock.Now()
if !entry.known {
pool.newQueue.remove(entry)
entry.known = true
}
pool.knownQueue.setLatest(entry)
entry.shortRetry = shortRetryCnt
close(req.done)
case req := <-pool.disconnCh:
// Handle peer disconnection requests.
disconnect(req, req.stopped)
case <-pool.quit:
if pool.discSetPeriod != nil {
close(pool.discSetPeriod)
}
// Spawn a goroutine to close the disconnCh after all connections are disconnected.
go func() {
pool.connWg.Wait()
close(pool.disconnCh)
}()
// Handle all remaining disconnection requests before exit.
for req := range pool.disconnCh {
disconnect(req, true)
}
pool.saveNodes()
pool.wg.Done()
return
}
}
}
func (pool *serverPool) findOrNewNode(node *enode.Node) *poolEntry {
now := mclock.Now()
entry := pool.entries[node.ID()]
if entry == nil {
log.Debug("Discovered new entry", "id", node.ID())
entry = &poolEntry{
node: node,
addr: make(map[string]*poolEntryAddress),
addrSelect: *newWeightedRandomSelect(),
shortRetry: shortRetryCnt,
}
pool.entries[node.ID()] = entry
// initialize previously unknown peers with good statistics to give a chance to prove themselves
entry.connectStats.add(1, initStatsWeight)
entry.delayStats.add(0, initStatsWeight)
entry.responseStats.add(0, initStatsWeight)
entry.timeoutStats.add(0, initStatsWeight)
}
entry.lastDiscovered = now
addr := &poolEntryAddress{ip: node.IP(), port: uint16(node.TCP())}
if a, ok := entry.addr[addr.strKey()]; ok {
addr = a
} else {
entry.addr[addr.strKey()] = addr
}
addr.lastSeen = now
entry.addrSelect.update(addr)
if !entry.known {
pool.newQueue.setLatest(entry)
}
return entry
}
// loadNodes loads known nodes and their statistics from the database
func (pool *serverPool) loadNodes() {
enc, err := pool.db.Get(pool.dbKey)
if err != nil {
return
}
var list []*poolEntry
err = rlp.DecodeBytes(enc, &list)
if err != nil {
log.Debug("Failed to decode node list", "err", err)
return
}
for _, e := range list {
log.Debug("Loaded server stats", "id", e.node.ID(), "fails", e.lastConnected.fails,
"conn", fmt.Sprintf("%v/%v", e.connectStats.avg, e.connectStats.weight),
"delay", fmt.Sprintf("%v/%v", time.Duration(e.delayStats.avg), e.delayStats.weight),
"response", fmt.Sprintf("%v/%v", time.Duration(e.responseStats.avg), e.responseStats.weight),
"timeout", fmt.Sprintf("%v/%v", e.timeoutStats.avg, e.timeoutStats.weight))
pool.entries[e.node.ID()] = e
if pool.trustedNodes[e.node.ID()] == nil {
pool.knownQueue.setLatest(e)
pool.knownSelect.update((*knownEntry)(e))
}
}
}
// connectToTrustedNodes adds trusted server nodes as static trusted peers.
//
// Note: trusted nodes are not handled by the server pool logic, they are not
// added to either the known or new selection pools. They are connected/reconnected
// by p2p.Server whenever possible.
func (pool *serverPool) connectToTrustedNodes() {
//connect to trusted nodes
for _, node := range pool.trustedNodes {
pool.server.AddTrustedPeer(node)
pool.server.AddPeer(node)
log.Debug("Added trusted node", "id", node.ID().String())
}
}
// parseTrustedNodes returns valid and parsed enodes
func parseTrustedNodes(trustedNodes []string) map[enode.ID]*enode.Node {
nodes := make(map[enode.ID]*enode.Node)
for _, node := range trustedNodes {
node, err := enode.Parse(enode.ValidSchemes, node)
if err != nil {
log.Warn("Trusted node URL invalid", "enode", node, "err", err)
continue
}
nodes[node.ID()] = node
}
return nodes
}
// saveNodes saves known nodes and their statistics into the database. Nodes are
// ordered from least to most recently connected.
func (pool *serverPool) saveNodes() {
list := make([]*poolEntry, len(pool.knownQueue.queue))
for i := range list {
list[i] = pool.knownQueue.fetchOldest()
}
enc, err := rlp.EncodeToBytes(list)
if err == nil {
pool.db.Put(pool.dbKey, enc)
}
}
// removeEntry removes a pool entry when the entry count limit is reached.
// Note that it is called by the new/known queues from which the entry has already
// been removed so removing it from the queues is not necessary.
func (pool *serverPool) removeEntry(entry *poolEntry) {
pool.newSelect.remove((*discoveredEntry)(entry))
pool.knownSelect.remove((*knownEntry)(entry))
entry.removed = true
delete(pool.entries, entry.node.ID())
}
// setRetryDial starts the timer which will enable dialing a certain node again
func (pool *serverPool) setRetryDial(entry *poolEntry) {
delay := longRetryDelay
if entry.shortRetry > 0 {
entry.shortRetry--
delay = shortRetryDelay
}
delay += time.Duration(rand.Int63n(int64(delay) + 1))
entry.delayedRetry = true
go func() {
select {
case <-pool.quit:
case <-time.After(delay):
select {
case <-pool.quit:
case pool.enableRetry <- entry:
}
}
}()
}
// updateCheckDial is called when an entry can potentially be dialed again. It updates
// its selection weights and checks if new dials can/should be made.
func (pool *serverPool) updateCheckDial(entry *poolEntry) {
pool.newSelect.update((*discoveredEntry)(entry))
pool.knownSelect.update((*knownEntry)(entry))
pool.checkDial()
}
// checkDial checks if new dials can/should be made. It tries to select servers both
// based on good statistics and recent discovery.
func (pool *serverPool) checkDial() {
fillWithKnownSelects := !pool.fastDiscover
for pool.knownSelected < targetKnownSelect {
entry := pool.knownSelect.choose()
if entry == nil {
fillWithKnownSelects = false
break
}
pool.dial((*poolEntry)(entry.(*knownEntry)), true)
}
for pool.knownSelected+pool.newSelected < targetServerCount {
entry := pool.newSelect.choose()
if entry == nil {
break
}
pool.dial((*poolEntry)(entry.(*discoveredEntry)), false)
}
if fillWithKnownSelects {
// no more newly discovered nodes to select and since fast discover period
// is over, we probably won't find more in the near future so select more
// known entries if possible
for pool.knownSelected < targetServerCount {
entry := pool.knownSelect.choose()
if entry == nil {
break
}
pool.dial((*poolEntry)(entry.(*knownEntry)), true)
}
}
}
// dial initiates a new connection
func (pool *serverPool) dial(entry *poolEntry, knownSelected bool) {
if pool.server == nil || entry.state != psNotConnected {
return
}
entry.state = psDialed
entry.knownSelected = knownSelected
if knownSelected {
pool.knownSelected++
} else {
pool.newSelected++
}
addr := entry.addrSelect.choose().(*poolEntryAddress)
log.Debug("Dialing new peer", "lesaddr", entry.node.ID().String()+"@"+addr.strKey(), "set", len(entry.addr), "known", knownSelected)
entry.dialed = addr
go func() {
pool.server.AddPeer(entry.node)
select {
case <-pool.quit:
case <-time.After(dialTimeout):
select {
case <-pool.quit:
case pool.timeout <- entry:
}
}
}()
}
// checkDialTimeout checks if the node is still in dialed state and if so, resets it
// and adjusts connection statistics accordingly.
func (pool *serverPool) checkDialTimeout(entry *poolEntry) {
if entry.state != psDialed {
return
}
log.Debug("Dial timeout", "lesaddr", entry.node.ID().String()+"@"+entry.dialed.strKey())
entry.state = psNotConnected
if entry.knownSelected {
pool.knownSelected--
} else {
pool.newSelected--
}
entry.connectStats.add(0, 1)
entry.dialed.fails++
pool.setRetryDial(entry)
}
const (
psNotConnected = iota
psDialed
psConnected
psRegistered
)
// poolEntry represents a server node and stores its current state and statistics.
type poolEntry struct {
peer *peer
pubkey [64]byte // secp256k1 key of the node
addr map[string]*poolEntryAddress
node *enode.Node
lastConnected, dialed *poolEntryAddress
addrSelect weightedRandomSelect
lastDiscovered mclock.AbsTime
known, knownSelected bool
connectStats, delayStats poolStats
responseStats, timeoutStats poolStats
state int
regTime mclock.AbsTime
queueIdx int
removed bool
delayedRetry bool
shortRetry int
}
// poolEntryEnc is the RLP encoding of poolEntry.
type poolEntryEnc struct {
Pubkey []byte
IP net.IP
Port uint16
Fails uint
CStat, DStat, RStat, TStat poolStats
}
func (e *poolEntry) EncodeRLP(w io.Writer) error {
return rlp.Encode(w, &poolEntryEnc{
Pubkey: encodePubkey64(e.node.Pubkey()),
IP: e.lastConnected.ip,
Port: e.lastConnected.port,
Fails: e.lastConnected.fails,
CStat: e.connectStats,
DStat: e.delayStats,
RStat: e.responseStats,
TStat: e.timeoutStats,
})
}
func (e *poolEntry) DecodeRLP(s *rlp.Stream) error {
var entry poolEntryEnc
if err := s.Decode(&entry); err != nil {
return err
}
pubkey, err := decodePubkey64(entry.Pubkey)
if err != nil {
return err
}
addr := &poolEntryAddress{ip: entry.IP, port: entry.Port, fails: entry.Fails, lastSeen: mclock.Now()}
e.node = enode.NewV4(pubkey, entry.IP, int(entry.Port), int(entry.Port))
e.addr = make(map[string]*poolEntryAddress)
e.addr[addr.strKey()] = addr
e.addrSelect = *newWeightedRandomSelect()
e.addrSelect.update(addr)
e.lastConnected = addr
e.connectStats = entry.CStat
e.delayStats = entry.DStat
e.responseStats = entry.RStat
e.timeoutStats = entry.TStat
e.shortRetry = shortRetryCnt
e.known = true
return nil
}
func encodePubkey64(pub *ecdsa.PublicKey) []byte {
return crypto.FromECDSAPub(pub)[1:]
}
func decodePubkey64(b []byte) (*ecdsa.PublicKey, error) {
return crypto.UnmarshalPubkey(append([]byte{0x04}, b...))
}
// discoveredEntry implements wrsItem
type discoveredEntry poolEntry
// Weight calculates random selection weight for newly discovered entries
func (e *discoveredEntry) Weight() int64 {
if e.state != psNotConnected || e.delayedRetry {
return 0
}
t := time.Duration(mclock.Now() - e.lastDiscovered)
if t <= discoverExpireStart {
return 1000000000
}
return int64(1000000000 * math.Exp(-float64(t-discoverExpireStart)/float64(discoverExpireConst)))
}
// knownEntry implements wrsItem
type knownEntry poolEntry
// Weight calculates random selection weight for known entries
func (e *knownEntry) Weight() int64 {
if e.state != psNotConnected || !e.known || e.delayedRetry {
return 0
}
return int64(1000000000 * e.connectStats.recentAvg() * math.Exp(-float64(e.lastConnected.fails)*failDropLn-e.responseStats.recentAvg()/float64(responseScoreTC)-e.delayStats.recentAvg()/float64(delayScoreTC)) * math.Pow(1-e.timeoutStats.recentAvg(), timeoutPow))
}
// poolEntryAddress is a separate object because currently it is necessary to remember
// multiple potential network addresses for a pool entry. This will be removed after
// the final implementation of v5 discovery which will retrieve signed and serial
// numbered advertisements, making it clear which IP/port is the latest one.
type poolEntryAddress struct {
ip net.IP
port uint16
lastSeen mclock.AbsTime // last time it was discovered, connected or loaded from db
fails uint // connection failures since last successful connection (persistent)
}
func (a *poolEntryAddress) Weight() int64 {
t := time.Duration(mclock.Now() - a.lastSeen)
return int64(1000000*math.Exp(-float64(t)/float64(discoverExpireConst)-float64(a.fails)*addrFailDropLn)) + 1
}
func (a *poolEntryAddress) strKey() string {
return a.ip.String() + ":" + strconv.Itoa(int(a.port))
}
// poolStats implement statistics for a certain quantity with a long term average
// and a short term value which is adjusted exponentially with a factor of
// pstatRecentAdjust with each update and also returned exponentially to the
// average with the time constant pstatReturnToMeanTC
type poolStats struct {
sum, weight, avg, recent float64
lastRecalc mclock.AbsTime
}
// init initializes stats with a long term sum/update count pair retrieved from the database
func (s *poolStats) init(sum, weight float64) {
s.sum = sum
s.weight = weight
var avg float64
if weight > 0 {
avg = s.sum / weight
}
s.avg = avg
s.recent = avg
s.lastRecalc = mclock.Now()
}
// recalc recalculates recent value return-to-mean and long term average
func (s *poolStats) recalc() {
now := mclock.Now()
s.recent = s.avg + (s.recent-s.avg)*math.Exp(-float64(now-s.lastRecalc)/float64(pstatReturnToMeanTC))
if s.sum == 0 {
s.avg = 0
} else {
if s.sum > s.weight*1e30 {
s.avg = 1e30
} else {
s.avg = s.sum / s.weight
}
}
s.lastRecalc = now
}
// add updates the stats with a new value
func (s *poolStats) add(value, weight float64) {
s.weight += weight
s.sum += value * weight
s.recalc()
}
// recentAvg returns the short-term adjusted average
func (s *poolStats) recentAvg() float64 {
s.recalc()
return s.recent
}
func (s *poolStats) EncodeRLP(w io.Writer) error {
return rlp.Encode(w, []interface{}{math.Float64bits(s.sum), math.Float64bits(s.weight)})
}
func (s *poolStats) DecodeRLP(st *rlp.Stream) error {
var stats struct {
SumUint, WeightUint uint64
}
if err := st.Decode(&stats); err != nil {
return err
}
s.init(math.Float64frombits(stats.SumUint), math.Float64frombits(stats.WeightUint))
return nil
}
// poolEntryQueue keeps track of its least recently accessed entries and removes
// them when the number of entries reaches the limit
type poolEntryQueue struct {
queue map[int]*poolEntry // known nodes indexed by their latest lastConnCnt value
newPtr, oldPtr, maxCnt int
removeFromPool func(*poolEntry)
}
// newPoolEntryQueue returns a new poolEntryQueue
func newPoolEntryQueue(maxCnt int, removeFromPool func(*poolEntry)) poolEntryQueue {
return poolEntryQueue{queue: make(map[int]*poolEntry), maxCnt: maxCnt, removeFromPool: removeFromPool}
}
// fetchOldest returns and removes the least recently accessed entry
func (q *poolEntryQueue) fetchOldest() *poolEntry {
if len(q.queue) == 0 {
return nil
}
for {
if e := q.queue[q.oldPtr]; e != nil {
delete(q.queue, q.oldPtr)
q.oldPtr++
return e
}
q.oldPtr++
}
}
// remove removes an entry from the queue
func (q *poolEntryQueue) remove(entry *poolEntry) {
if q.queue[entry.queueIdx] == entry {
delete(q.queue, entry.queueIdx)
}
}
// setLatest adds or updates a recently accessed entry. It also checks if an old entry
// needs to be removed and removes it from the parent pool too with a callback function.
func (q *poolEntryQueue) setLatest(entry *poolEntry) {
if q.queue[entry.queueIdx] == entry {
delete(q.queue, entry.queueIdx)
} else {
if len(q.queue) == q.maxCnt {
e := q.fetchOldest()
q.remove(e)
q.removeFromPool(e)
}
}
entry.queueIdx = q.newPtr
q.queue[entry.queueIdx] = entry
q.newPtr++
}