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520 lines
14 KiB
520 lines
14 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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. "github.com/tendermint/tendermint/binary"
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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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"io"
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"math"
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"math/rand"
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"net"
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"sync"
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"sync/atomic"
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"time"
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"os"
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"fmt"
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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 // addr.String() -> KnownAddress
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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 getAddr
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// (in practise the most addresses we will return from a call to AddressCache()).
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getAddrMax = 2500
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// % of total addresses known that we will share with a call to AddressCache.
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getAddrPercent = 23
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// current version of the on-disk format.
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serialisationVersion = 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 { return }
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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 { return }
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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(); 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.NumAddresses() < needAddressThreshold
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}
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func (a *AddrBook) NumAddresses() int {
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a.mtx.Lock(); defer a.mtx.Unlock()
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return a.nOld + a.nNew
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}
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// Pick a new address to connect to.
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func (a *AddrBook) PickAddress(class string, newBias int) *KnownAddress {
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a.mtx.Lock(); defer a.mtx.Unlock()
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if a.nOld == 0 && a.nNew == 0 { return nil }
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if newBias > 100 { newBias = 100 }
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if newBias < 0 { newBias = 0 }
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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(); defer a.mtx.Unlock()
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ka := a.addrIndex[addr.String()]
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if ka == nil { return }
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ka.MarkAttempt(true)
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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(); defer a.mtx.Unlock()
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ka := a.addrIndex[addr.String()]
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if ka == nil { return }
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ka.MarkAttempt(false)
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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]map[string]*KnownAddress
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AddrOld [oldBucketCount][]*KnownAddress
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NOld int
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NNew int
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}
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func (a *AddrBook) saveToFile(filePath string) {
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aJSON := &addrBookJSON{
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Key: a.key,
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AddrNew: a.addrNew,
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AddrOld: a.addrOld,
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NOld: a.nOld,
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NNew: 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 { panic(err) }
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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) { return }
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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 initialize self.
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copy(a.key[:], aJSON.Key[:])
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a.addrNew = aJSON.AddrNew
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for i, oldBucket := range aJSON.AddrOld {
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copy(a.addrOld[i], oldBucket)
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}
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a.nNew = aJSON.NNew
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a.nOld = aJSON.NOld
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a.addrIndex = make(map[string]*KnownAddress)
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for _, newBucket := range a.addrNew {
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for key, ka := range newBucket {
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a.addrIndex[key] = ka
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}
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}
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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() { return }
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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 { return }
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if ka.NewRefs == newBucketsPerAddress { return }
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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.Bad() {
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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 { panic("Expected to find addr in at least one new bucket") }
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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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}
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// Return a string representing the network group of this address.
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// This is the /16 for IPv6, the /32 (/36 for he.net) for IPv6, the string
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// "local" for a local address and the string "unroutable for an unroutable
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// address.
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func GroupKey (na *NetAddress) string {
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if na.Local() {
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return "local"
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}
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if !na.Routable() {
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return "unroutable"
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}
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if ipv4 := na.IP.To4(); ipv4 != nil {
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return (&net.IPNet{IP: na.IP, Mask: net.CIDRMask(16, 32)}).String()
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}
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if na.RFC6145() || na.RFC6052() {
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// last four bytes are the ip address
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ip := net.IP(na.IP[12:16])
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return (&net.IPNet{IP: ip, Mask: net.CIDRMask(16, 32)}).String()
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}
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if na.RFC3964() {
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ip := net.IP(na.IP[2:7])
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return (&net.IPNet{IP: ip, Mask: net.CIDRMask(16, 32)}).String()
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}
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if na.RFC4380() {
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// teredo tunnels have the last 4 bytes as the v4 address XOR
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// 0xff.
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ip := net.IP(make([]byte, 4))
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for i, byte := range na.IP[12:16] {
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ip[i] = byte ^ 0xff
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}
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return (&net.IPNet{IP: ip, Mask: net.CIDRMask(16, 32)}).String()
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}
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// OK, so now we know ourselves to be a IPv6 address.
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// bitcoind uses /32 for everything, except for Hurricane Electric's
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// (he.net) IP range, which it uses /36 for.
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bits := 32
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heNet := &net.IPNet{IP: net.ParseIP("2001:470::"),
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Mask: net.CIDRMask(32, 128)}
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if heNet.Contains(na.IP) {
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bits = 36
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}
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return (&net.IPNet{IP: na.IP, Mask: net.CIDRMask(bits, 128)}).String()
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}
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