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701 lines
16 KiB
701 lines
16 KiB
// Modified for Tendermint
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// Originally Copyright (c) 2013-2014 Conformal Systems LLC.
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// https://github.com/conformal/btcd/blob/master/LICENSE
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package peer
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import (
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crand "crypto/rand" // for seeding
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"encoding/binary"
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"encoding/json"
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"fmt"
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"io"
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"math"
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"math/rand"
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"net"
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"os"
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"sync"
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"sync/atomic"
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"time"
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. "github.com/tendermint/tendermint/binary"
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)
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/* AddrBook - concurrency safe peer address manager */
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type AddrBook struct {
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filePath string
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mtx sync.Mutex
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rand *rand.Rand
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key [32]byte
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addrIndex map[string]*knownAddress // new & old
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addrNew [newBucketCount]map[string]*knownAddress
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addrOld [oldBucketCount][]*knownAddress
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started int32
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shutdown int32
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wg sync.WaitGroup
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quit chan struct{}
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nOld int
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nNew int
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}
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const (
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// addresses under which the address manager will claim to need more addresses.
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needAddressThreshold = 1000
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// interval used to dump the address cache to disk for future use.
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dumpAddressInterval = time.Minute * 2
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// max addresses in each old address bucket.
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oldBucketSize = 64
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// buckets we split old addresses over.
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oldBucketCount = 64
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// max addresses in each new address bucket.
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newBucketSize = 64
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// buckets that we spread new addresses over.
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newBucketCount = 256
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// old buckets over which an address group will be spread.
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oldBucketsPerGroup = 4
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// new buckets over which an source address group will be spread.
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newBucketsPerGroup = 32
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// buckets a frequently seen new address may end up in.
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newBucketsPerAddress = 4
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// days before which we assume an address has vanished
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// if we have not seen it announced in that long.
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numMissingDays = 30
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// tries without a single success before we assume an address is bad.
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numRetries = 3
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// max failures we will accept without a success before considering an address bad.
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maxFailures = 10
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// days since the last success before we will consider evicting an address.
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minBadDays = 7
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// max addresses that we will send in response to a GetSelection
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getSelectionMax = 2500
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// % of total addresses known that we will share with a call to GetSelection
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getSelectionPercent = 23
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// current version of the on-disk format.
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serializationVersion = 1
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)
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// Use Start to begin processing asynchronous address updates.
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func NewAddrBook(filePath string) *AddrBook {
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am := AddrBook{
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rand: rand.New(rand.NewSource(time.Now().UnixNano())),
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quit: make(chan struct{}),
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filePath: filePath,
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}
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am.init()
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return &am
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}
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// When modifying this, don't forget to update loadFromFile()
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func (a *AddrBook) init() {
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a.addrIndex = make(map[string]*knownAddress)
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io.ReadFull(crand.Reader, a.key[:])
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for i := range a.addrNew {
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a.addrNew[i] = make(map[string]*knownAddress)
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}
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for i := range a.addrOld {
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a.addrOld[i] = make([]*knownAddress, 0, oldBucketSize)
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}
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}
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func (a *AddrBook) Start() {
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if atomic.AddInt32(&a.started, 1) != 1 {
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return
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}
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log.Trace("Starting address manager")
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a.loadFromFile(a.filePath)
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a.wg.Add(1)
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go a.addressHandler()
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}
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func (a *AddrBook) Stop() {
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if atomic.AddInt32(&a.shutdown, 1) != 1 {
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return
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}
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log.Infof("Address manager shutting down")
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close(a.quit)
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a.wg.Wait()
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}
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func (a *AddrBook) AddAddress(addr *NetAddress, src *NetAddress) {
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a.mtx.Lock()
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defer a.mtx.Unlock()
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a.addAddress(addr, src)
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}
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func (a *AddrBook) NeedMoreAddresses() bool {
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return a.Size() < needAddressThreshold
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}
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func (a *AddrBook) Size() int {
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a.mtx.Lock()
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defer a.mtx.Unlock()
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return a.size()
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}
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func (a *AddrBook) size() int {
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return a.nNew + a.nOld
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}
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// Pick an address to connect to with new/old bias.
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func (a *AddrBook) PickAddress(newBias int) *knownAddress {
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a.mtx.Lock()
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defer a.mtx.Unlock()
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if a.nOld == 0 && a.nNew == 0 {
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return nil
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}
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if newBias > 100 {
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newBias = 100
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}
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if newBias < 0 {
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newBias = 0
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}
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// Bias between new and old addresses.
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oldCorrelation := math.Sqrt(float64(a.nOld)) * (100.0 - float64(newBias))
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newCorrelation := math.Sqrt(float64(a.nNew)) * float64(newBias)
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if (newCorrelation+oldCorrelation)*a.rand.Float64() < oldCorrelation {
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// pick random Old bucket.
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var bucket []*knownAddress = nil
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for len(bucket) == 0 {
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bucket = a.addrOld[a.rand.Intn(len(a.addrOld))]
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}
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// pick a random ka from bucket.
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return bucket[a.rand.Intn(len(bucket))]
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} else {
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// pick random New bucket.
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var bucket map[string]*knownAddress = nil
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for len(bucket) == 0 {
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bucket = a.addrNew[a.rand.Intn(len(a.addrNew))]
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}
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// pick a random ka from bucket.
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randIndex := a.rand.Intn(len(bucket))
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for _, ka := range bucket {
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randIndex--
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if randIndex == 0 {
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return ka
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}
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}
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panic("Should not happen")
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}
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return nil
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}
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func (a *AddrBook) MarkGood(addr *NetAddress) {
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a.mtx.Lock()
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defer a.mtx.Unlock()
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ka := a.addrIndex[addr.String()]
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if ka == nil {
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return
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}
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ka.MarkGood()
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if ka.OldBucket == -1 {
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a.moveToOld(ka)
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}
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}
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func (a *AddrBook) MarkAttempt(addr *NetAddress) {
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a.mtx.Lock()
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defer a.mtx.Unlock()
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ka := a.addrIndex[addr.String()]
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if ka == nil {
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return
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}
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ka.MarkAttempt()
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}
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/* Peer exchange */
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// GetSelection randomly selects some addresses (old & new). Suitable for peer-exchange protocols.
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func (a *AddrBook) GetSelection() []*NetAddress {
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a.mtx.Lock()
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defer a.mtx.Unlock()
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if a.size() == 0 {
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return nil
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}
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allAddr := make([]*NetAddress, a.size())
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i := 0
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for _, v := range a.addrIndex {
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allAddr[i] = v.Addr
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i++
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}
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numAddresses := len(allAddr) * getSelectionPercent / 100
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if numAddresses > getSelectionMax {
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numAddresses = getSelectionMax
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}
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// Fisher-Yates shuffle the array. We only need to do the first
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// `numAddresses' since we are throwing the rest.
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for i := 0; i < numAddresses; i++ {
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// pick a number between current index and the end
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j := rand.Intn(len(allAddr)-i) + i
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allAddr[i], allAddr[j] = allAddr[j], allAddr[i]
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}
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// slice off the limit we are willing to share.
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return allAddr[:numAddresses]
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}
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/* Loading & Saving */
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type addrBookJSON struct {
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Key [32]byte
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AddrNew [newBucketCount][]*knownAddress
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AddrOld [oldBucketCount][]*knownAddress
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NumOld int
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NumNew int
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}
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func (a *AddrBook) saveToFile(filePath string) {
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// turn a.addrNew into an array like a.addrOld
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__addrNew := [newBucketCount][]*knownAddress{}
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for i, newBucket := range a.addrNew {
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var array []*knownAddress = make([]*knownAddress, 0)
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for _, ka := range newBucket {
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array = append(array, ka)
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}
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__addrNew[i] = array
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}
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aJSON := &addrBookJSON{
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Key: a.key,
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AddrNew: __addrNew,
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AddrOld: a.addrOld,
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NumOld: a.nOld,
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NumNew: a.nNew,
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}
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w, err := os.Create(filePath)
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if err != nil {
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log.Error("Error opening file: ", filePath, err)
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return
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}
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enc := json.NewEncoder(w)
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defer w.Close()
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err = enc.Encode(&aJSON)
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if err != nil {
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panic(err)
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}
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}
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func (a *AddrBook) loadFromFile(filePath string) {
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// If doesn't exist, do nothing.
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_, err := os.Stat(filePath)
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if os.IsNotExist(err) {
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return
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}
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// Load addrBookJSON{}
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r, err := os.Open(filePath)
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if err != nil {
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panic(fmt.Errorf("%s error opening file: %v", filePath, err))
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}
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defer r.Close()
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aJSON := &addrBookJSON{}
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dec := json.NewDecoder(r)
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err = dec.Decode(aJSON)
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if err != nil {
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panic(fmt.Errorf("error reading %s: %v", filePath, err))
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}
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// Now we need to restore the fields
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// Restore the key
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copy(a.key[:], aJSON.Key[:])
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// Restore .addrNew
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for i, newBucket := range aJSON.AddrNew {
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for _, ka := range newBucket {
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a.addrNew[i][ka.Addr.String()] = ka
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a.addrIndex[ka.Addr.String()] = ka
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}
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}
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// Restore .addrOld
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for i, oldBucket := range aJSON.AddrOld {
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copy(a.addrOld[i], oldBucket)
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for _, ka := range oldBucket {
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a.addrIndex[ka.Addr.String()] = ka
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}
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}
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// Restore simple fields
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a.nNew = aJSON.NumNew
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a.nOld = aJSON.NumOld
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}
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/* Private methods */
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func (a *AddrBook) addressHandler() {
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dumpAddressTicker := time.NewTicker(dumpAddressInterval)
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out:
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for {
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select {
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case <-dumpAddressTicker.C:
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a.saveToFile(a.filePath)
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case <-a.quit:
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break out
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}
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}
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dumpAddressTicker.Stop()
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a.saveToFile(a.filePath)
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a.wg.Done()
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log.Trace("Address handler done")
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}
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func (a *AddrBook) addAddress(addr, src *NetAddress) {
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if !addr.Routable() {
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return
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}
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key := addr.String()
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ka := a.addrIndex[key]
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if ka != nil {
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// Already added
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if ka.OldBucket != -1 {
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return
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}
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if ka.NewRefs == newBucketsPerAddress {
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return
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}
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// The more entries we have, the less likely we are to add more.
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factor := int32(2 * ka.NewRefs)
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if a.rand.Int31n(factor) != 0 {
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return
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}
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} else {
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ka = NewknownAddress(addr, src)
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a.addrIndex[key] = ka
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a.nNew++
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}
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bucket := a.getNewBucket(addr, src)
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// Already exists?
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if _, ok := a.addrNew[bucket][key]; ok {
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return
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}
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// Enforce max addresses.
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if len(a.addrNew[bucket]) > newBucketSize {
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log.Tracef("new bucket is full, expiring old ")
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a.expireNew(bucket)
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}
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// Add to new bucket.
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ka.NewRefs++
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a.addrNew[bucket][key] = ka
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log.Tracef("Added new address %s for a total of %d addresses", addr, a.nOld+a.nNew)
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}
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// Make space in the new buckets by expiring the really bad entries.
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// If no bad entries are available we look at a few and remove the oldest.
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func (a *AddrBook) expireNew(bucket int) {
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var oldest *knownAddress
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for k, v := range a.addrNew[bucket] {
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// If an entry is bad, throw it away
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if v.IsBad() {
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log.Tracef("expiring bad address %v", k)
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delete(a.addrNew[bucket], k)
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v.NewRefs--
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if v.NewRefs == 0 {
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a.nNew--
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delete(a.addrIndex, k)
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}
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return
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}
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// or, keep track of the oldest entry
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if oldest == nil {
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oldest = v
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} else if v.LastAttempt.Before(oldest.LastAttempt.Time) {
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oldest = v
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}
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}
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// If we haven't thrown out a bad entry, throw out the oldest entry
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if oldest != nil {
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key := oldest.Addr.String()
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log.Tracef("expiring oldest address %v", key)
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delete(a.addrNew[bucket], key)
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oldest.NewRefs--
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if oldest.NewRefs == 0 {
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a.nNew--
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delete(a.addrIndex, key)
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}
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}
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}
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func (a *AddrBook) moveToOld(ka *knownAddress) {
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// Remove from all new buckets.
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// Remember one of those new buckets.
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addrKey := ka.Addr.String()
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freedBucket := -1
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for i := range a.addrNew {
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// we check for existance so we can record the first one
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if _, ok := a.addrNew[i][addrKey]; ok {
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delete(a.addrNew[i], addrKey)
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ka.NewRefs--
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if freedBucket == -1 {
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freedBucket = i
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}
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}
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}
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a.nNew--
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if freedBucket == -1 {
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panic("Expected to find addr in at least one new bucket")
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}
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oldBucket := a.getOldBucket(ka.Addr)
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// If room in oldBucket, put it in.
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if len(a.addrOld[oldBucket]) < oldBucketSize {
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ka.OldBucket = Int16(oldBucket)
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a.addrOld[oldBucket] = append(a.addrOld[oldBucket], ka)
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a.nOld++
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return
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}
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// No room, we have to evict something else.
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rmkaIndex := a.pickOld(oldBucket)
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rmka := a.addrOld[oldBucket][rmkaIndex]
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// Find a new bucket to put rmka in.
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newBucket := a.getNewBucket(rmka.Addr, rmka.Src)
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if len(a.addrNew[newBucket]) >= newBucketSize {
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newBucket = freedBucket
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}
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// Replace with ka in list.
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ka.OldBucket = Int16(oldBucket)
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a.addrOld[oldBucket][rmkaIndex] = ka
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rmka.OldBucket = -1
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// Put rmka into new bucket
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rmkey := rmka.Addr.String()
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log.Tracef("Replacing %s with %s in old", rmkey, addrKey)
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a.addrNew[newBucket][rmkey] = rmka
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rmka.NewRefs++
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a.nNew++
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}
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// Returns the index in old bucket of oldest entry.
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func (a *AddrBook) pickOld(bucket int) int {
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var oldest *knownAddress
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var oldestIndex int
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for i, ka := range a.addrOld[bucket] {
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if oldest == nil || ka.LastAttempt.Before(oldest.LastAttempt.Time) {
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oldest = ka
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oldestIndex = i
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}
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}
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return oldestIndex
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}
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// doublesha256(key + sourcegroup +
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// int64(doublesha256(key + group + sourcegroup))%bucket_per_source_group) % num_new_buckes
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func (a *AddrBook) getNewBucket(addr, src *NetAddress) int {
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data1 := []byte{}
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data1 = append(data1, a.key[:]...)
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data1 = append(data1, []byte(GroupKey(addr))...)
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data1 = append(data1, []byte(GroupKey(src))...)
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hash1 := DoubleSha256(data1)
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hash64 := binary.LittleEndian.Uint64(hash1)
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hash64 %= newBucketsPerGroup
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var hashbuf [8]byte
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binary.LittleEndian.PutUint64(hashbuf[:], hash64)
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data2 := []byte{}
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data2 = append(data2, a.key[:]...)
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data2 = append(data2, GroupKey(src)...)
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data2 = append(data2, hashbuf[:]...)
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hash2 := DoubleSha256(data2)
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return int(binary.LittleEndian.Uint64(hash2) % newBucketCount)
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}
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// doublesha256(key + group + truncate_to_64bits(doublesha256(key + addr))%buckets_per_group) % num_buckets
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func (a *AddrBook) getOldBucket(addr *NetAddress) int {
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data1 := []byte{}
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data1 = append(data1, a.key[:]...)
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data1 = append(data1, []byte(addr.String())...)
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hash1 := DoubleSha256(data1)
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hash64 := binary.LittleEndian.Uint64(hash1)
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hash64 %= oldBucketsPerGroup
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var hashbuf [8]byte
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binary.LittleEndian.PutUint64(hashbuf[:], hash64)
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data2 := []byte{}
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data2 = append(data2, a.key[:]...)
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data2 = append(data2, GroupKey(addr)...)
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data2 = append(data2, hashbuf[:]...)
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hash2 := DoubleSha256(data2)
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return int(binary.LittleEndian.Uint64(hash2) % oldBucketCount)
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}
|
|
|
|
// Return a string representing the network group of this address.
|
|
// This is the /16 for IPv6, the /32 (/36 for he.net) for IPv6, the string
|
|
// "local" for a local address and the string "unroutable for an unroutable
|
|
// address.
|
|
func GroupKey(na *NetAddress) string {
|
|
if na.Local() {
|
|
return "local"
|
|
}
|
|
if !na.Routable() {
|
|
return "unroutable"
|
|
}
|
|
|
|
if ipv4 := na.IP.To4(); ipv4 != nil {
|
|
return (&net.IPNet{IP: na.IP, Mask: net.CIDRMask(16, 32)}).String()
|
|
}
|
|
if na.RFC6145() || na.RFC6052() {
|
|
// last four bytes are the ip address
|
|
ip := net.IP(na.IP[12:16])
|
|
return (&net.IPNet{IP: ip, Mask: net.CIDRMask(16, 32)}).String()
|
|
}
|
|
|
|
if na.RFC3964() {
|
|
ip := net.IP(na.IP[2:7])
|
|
return (&net.IPNet{IP: ip, Mask: net.CIDRMask(16, 32)}).String()
|
|
|
|
}
|
|
if na.RFC4380() {
|
|
// teredo tunnels have the last 4 bytes as the v4 address XOR
|
|
// 0xff.
|
|
ip := net.IP(make([]byte, 4))
|
|
for i, byte := range na.IP[12:16] {
|
|
ip[i] = byte ^ 0xff
|
|
}
|
|
return (&net.IPNet{IP: ip, Mask: net.CIDRMask(16, 32)}).String()
|
|
}
|
|
|
|
// OK, so now we know ourselves to be a IPv6 address.
|
|
// bitcoind uses /32 for everything, except for Hurricane Electric's
|
|
// (he.net) IP range, which it uses /36 for.
|
|
bits := 32
|
|
heNet := &net.IPNet{IP: net.ParseIP("2001:470::"),
|
|
Mask: net.CIDRMask(32, 128)}
|
|
if heNet.Contains(na.IP) {
|
|
bits = 36
|
|
}
|
|
|
|
return (&net.IPNet{IP: na.IP, Mask: net.CIDRMask(bits, 128)}).String()
|
|
}
|
|
|
|
/*
|
|
knownAddress
|
|
|
|
tracks information about a known network address that is used
|
|
to determine how viable an address is.
|
|
*/
|
|
type knownAddress struct {
|
|
Addr *NetAddress
|
|
Src *NetAddress
|
|
Attempts UInt32
|
|
LastAttempt Time
|
|
LastSuccess Time
|
|
NewRefs UInt16
|
|
OldBucket Int16
|
|
}
|
|
|
|
func NewknownAddress(addr *NetAddress, src *NetAddress) *knownAddress {
|
|
return &knownAddress{
|
|
Addr: addr,
|
|
Src: src,
|
|
OldBucket: -1,
|
|
LastAttempt: Time{time.Now()},
|
|
Attempts: 0,
|
|
}
|
|
}
|
|
|
|
func ReadknownAddress(r io.Reader) *knownAddress {
|
|
return &knownAddress{
|
|
Addr: ReadNetAddress(r),
|
|
Src: ReadNetAddress(r),
|
|
Attempts: ReadUInt32(r),
|
|
LastAttempt: ReadTime(r),
|
|
LastSuccess: ReadTime(r),
|
|
NewRefs: ReadUInt16(r),
|
|
OldBucket: ReadInt16(r),
|
|
}
|
|
}
|
|
|
|
func (ka *knownAddress) WriteTo(w io.Writer) (n int64, err error) {
|
|
n, err = WriteOnto(ka.Addr, w, n, err)
|
|
n, err = WriteOnto(ka.Src, w, n, err)
|
|
n, err = WriteOnto(ka.Attempts, w, n, err)
|
|
n, err = WriteOnto(ka.LastAttempt, w, n, err)
|
|
n, err = WriteOnto(ka.LastSuccess, w, n, err)
|
|
n, err = WriteOnto(ka.NewRefs, w, n, err)
|
|
n, err = WriteOnto(ka.OldBucket, w, n, err)
|
|
return
|
|
}
|
|
|
|
func (ka *knownAddress) MarkAttempt() {
|
|
now := Time{time.Now()}
|
|
ka.LastAttempt = now
|
|
ka.Attempts += 1
|
|
}
|
|
|
|
func (ka *knownAddress) MarkGood() {
|
|
now := Time{time.Now()}
|
|
ka.LastAttempt = now
|
|
ka.Attempts = 0
|
|
ka.LastSuccess = now
|
|
}
|
|
|
|
/*
|
|
An address is bad if the address in question has not been tried in the last
|
|
minute and meets one of the following criteria:
|
|
|
|
1) It claims to be from the future
|
|
2) It hasn't been seen in over a month
|
|
3) It has failed at least three times and never succeeded
|
|
4) It has failed ten times in the last week
|
|
|
|
All addresses that meet these criteria are assumed to be worthless and not
|
|
worth keeping hold of.
|
|
*/
|
|
func (ka *knownAddress) IsBad() bool {
|
|
// Has been attempted in the last minute --> good
|
|
if ka.LastAttempt.Before(time.Now().Add(-1 * time.Minute)) {
|
|
return false
|
|
}
|
|
|
|
// Over a month old?
|
|
if ka.LastAttempt.After(time.Now().Add(-1 * numMissingDays * time.Hour * 24)) {
|
|
return true
|
|
}
|
|
|
|
// Never succeeded?
|
|
if ka.LastSuccess.IsZero() && ka.Attempts >= numRetries {
|
|
return true
|
|
}
|
|
|
|
// Hasn't succeeded in too long?
|
|
if ka.LastSuccess.Before(time.Now().Add(-1*minBadDays*time.Hour*24)) &&
|
|
ka.Attempts >= maxFailures {
|
|
return true
|
|
}
|
|
|
|
return false
|
|
}
|