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addrbook.go
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addrbook.go
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package addressbook
import (
crand "crypto/rand"
"encoding/binary"
"math/rand"
"net"
"path/filepath"
"sync"
"time"
"github.com/libp2p/go-libp2p-core/host"
"github.com/libp2p/go-libp2p-core/peer"
"github.com/spacemeshos/go-spacemesh/hash"
"github.com/spacemeshos/go-spacemesh/log"
)
// AddrBook provides a concurrency safe address manager for caching potential
// peers on the network. based on bitcoin's AddrBook.
type AddrBook struct {
host host.Host
cfg *Config
logger log.Log
path string
mu sync.RWMutex
rand *rand.Rand
key [32]byte
addrIndex map[peer.ID]*knownAddress
addrNew []map[peer.ID]*knownAddress
addrTried []map[peer.ID]*knownAddress
anchorPeers []*knownAddress // Anchor peers. store active connections, and use some of them when node starts.
lastAnchorPeers []*knownAddress // Anchor peers from last node start. Used only for bootstrap. New connections come to anchorPeers
nTried int
nNew int
}
// NewAddrBook returns a new address manager.
// Use Start to begin processing asynchronous address updates.
func NewAddrBook(cfg *Config, logger log.Log) *AddrBook {
path := ""
if len(cfg.DataDir) != 0 {
path = filepath.Join(cfg.DataDir, peersFileName)
}
am := AddrBook{
cfg: cfg,
logger: logger,
path: path,
rand: rand.New(rand.NewSource(time.Now().UnixNano())),
}
am.reset()
am.loadPeers(am.path)
return &am
}
// updateAddress is a helper function to either update an address already known
// to the address manager, or to add the address if not already known.
func (a *AddrBook) updateAddress(addr, src *AddrInfo) {
routableAddr := IsRoutable(addr.IP) || IsDNSAddress(addr.RawAddr)
if !routableAddr && IsRoutable(src.IP) {
a.logger.Debug("skipped non routable address received from routable ip",
log.String("received", addr.IP.String()),
log.String("from", src.IP.String()),
)
return
}
ka := a.lookup(addr.ID)
if ka != nil {
// Update the last seen time and services.
// note that to prevent causing excess garbage on getaddr
// messages the netaddresses in addrmaanger are *immutable*,
// if we need to change them then we replace the pointer with a
// new copy so that we don't have to copy every na for getaddr.
ka.LastSeen = time.Now()
if ka.Addr.RawAddr != addr.RawAddr {
a.logger.Debug("Update address",
log.String("old", ka.Addr.RawAddr),
log.String("new", addr.RawAddr),
)
ka.Addr = addr
}
// If already in tried, we have nothing to do here.
if ka.tried {
return
}
// Already at our max?
if ka.refs == a.cfg.NewBucketsPerAddress {
return
}
// The more entries we have, the less likely we are to add more.
// likelihood is 2N.
// factor := int32(2 * ka.refs)
// if a.rand.Int31n(factor) != 0 {
return
//}
}
// Make a copy of the net address to avoid races since it is
// updated elsewhere in the addrmanager code and would otherwise
// change the actual netaddress on the peer.
ka = &knownAddress{Addr: addr, SrcAddr: src, LastSeen: time.Now()}
a.addrIndex[addr.ID] = ka
a.nNew++
// XXX time penalty?
bucket := a.getNewBucket(addr.IP, src.IP)
// Already exists?
if _, ok := a.addrNew[bucket][addr.ID]; ok {
return
}
// Enforce max addresses.
if len(a.addrNew[bucket]) >= a.cfg.NewBucketSize {
a.logger.Debug("new bucket is full, expiring old")
a.expireNew(bucket)
}
// Add to new bucket.
ka.refs++
a.addrNew[bucket][addr.ID] = ka
a.logger.Debug("added new address %s for a total of %d addresses", addr.RawAddr, a.nTried+a.nNew)
}
// Lookup searches for an address using a public key. returns *Info.
func (a *AddrBook) Lookup(addr peer.ID) *AddrInfo {
a.mu.Lock()
d := a.lookup(addr)
a.mu.Unlock()
if d == nil {
return nil
}
return d.Addr
}
func (a *AddrBook) lookup(addr peer.ID) *knownAddress {
return a.addrIndex[addr]
}
// toTried moves a knownAddress to a tried bucket.
func (a *AddrBook) toTried(ka *knownAddress) {
// move to tried set, optionally evicting other addresses if neeed.
if ka.tried {
return
}
// ok, need to move it to tried.
addr := ka.Addr
// remove from all new buckets.
// record one of the buckets in question and call it the `first'
oldBucket := -1
for i := range a.addrNew {
// we check for existence so we can record the first one
if _, ok := a.addrNew[i][addr.ID]; ok {
delete(a.addrNew[i], addr.ID)
ka.refs--
if oldBucket == -1 {
oldBucket = i
}
}
}
if oldBucket == -1 {
// What? wasn't in a bucket after all.... Panic?
return
}
a.nNew--
bucket := a.getTriedBucket(addr.IP)
// Room in this tried bucket?
if len(a.addrTried[bucket]) < a.cfg.TriedBucketSize {
ka.tried = true
a.addrTried[bucket][addr.ID] = ka
a.nTried++
return
}
// No room, we have to evict something else.
rmka := a.pickTried(bucket)
// First bucket it would have been put in.
newBucket := a.getNewBucket(rmka.Addr.IP, rmka.SrcAddr.IP)
// If no room in the original bucket, we put it in a bucket we just
// freed up a space in.
if len(a.addrNew[newBucket]) >= a.cfg.NewBucketSize {
newBucket = oldBucket
}
// replace with ka in list.
ka.tried = true
a.addrTried[bucket][ka.Addr.ID] = ka
rmka.tried = false
rmka.refs++
// We don't touch a.nTried here since the number of tried stays the same
// but we decemented new above, raise it again since we're putting
// something back.
a.nNew++
rmkey := rmka.Addr.ID
a.logger.Debug("Replacing %s with %s in tried", rmkey, addr.ID)
// We made sure there is space here just above.
a.addrNew[newBucket][rmkey] = rmka
}
// pickTried selects an address from the tried bucket to be evicted.
// We just choose the eldest. Bitcoind selects 4 random entries and throws away
// the oldest of them.
func (a *AddrBook) pickTried(bucket int) *knownAddress {
var oldest *knownAddress
for _, ka := range a.addrTried[bucket] {
if oldest == nil || oldest.LastSeen.After(ka.LastSeen) {
oldest = ka
}
}
return oldest
}
// NumAddresses returns the number of addresses known to the address manager.
func (a *AddrBook) numAddresses() int {
return a.nTried + a.nNew
}
// NumAddresses returns the number of addresses known to the address manager.
func (a *AddrBook) NumAddresses() int {
a.mu.Lock()
defer a.mu.Unlock()
return a.numAddresses()
}
// getAddressFromBuckets selects an address from given slice of buckets.
func (a *AddrBook) getAddressFromBuckets(buckets []map[peer.ID]*knownAddress) *knownAddress {
nonEmptyBuckets := make([]int, 0, len(buckets)) // get non-empty buckets ids for reduce extracting time.
for i := range buckets {
if len(buckets[i]) > 0 {
nonEmptyBuckets = append(nonEmptyBuckets, i)
}
}
if len(nonEmptyBuckets) == 0 {
return nil // no addresses to extract.
}
large := 1 << 30
factor := 1.0
for {
// pick a random bucket.
bucket := nonEmptyBuckets[a.rand.Intn(len(nonEmptyBuckets))]
// Pick a random entry in it. Structure is map[peer.ID]*knownAddress, so we need loop to gen rand index.
var ka *knownAddress
nth := a.rand.Intn(len(buckets[bucket]))
for _, value := range buckets[bucket] {
if nth == 0 {
ka = value
}
nth--
}
randVal := a.rand.Intn(large)
if float64(randVal) < (factor * ka.Chance() * float64(large)) {
return ka
}
factor *= 1.2
}
}
// AddressCache returns the current address cache. It must be treated as
// read-only (but since it is a copy now, this is not as dangerous).
func (a *AddrBook) AddressCache() []*AddrInfo {
allAddr := a.GetAddresses()
numAddresses := len(allAddr) * a.cfg.GetAddrPercent / 100
if numAddresses > a.cfg.GetAddrMax {
numAddresses = a.cfg.GetAddrMax
} else if numAddresses == 0 {
numAddresses = len(allAddr)
}
result := make([]*AddrInfo, 0, numAddresses)
a.mu.RLock()
defer a.mu.RUnlock()
for i := 0; i < numAddresses; i++ {
var ka *knownAddress
// Use a 50% chance for choosing between tried and new table entries.
if a.nTried > 0 && (a.nNew == 0 || a.rand.Intn(2) == 0) {
ka = a.getAddressFromBuckets(a.addrTried)
} else {
ka = a.getAddressFromBuckets(a.addrNew)
}
if ka != nil {
result = append(result, ka.Addr)
}
}
return result
}
// BootstrapAddressCache run AddressCache and add Config.AnchorPeersCount addresses from anchor peers.
func (a *AddrBook) BootstrapAddressCache() []*AddrInfo {
addresses := a.AddressCache()
a.mu.RLock()
defer a.mu.RUnlock()
if len(a.lastAnchorPeers) == 0 {
return addresses
}
anchorPeers := make([]*knownAddress, len(a.lastAnchorPeers))
copy(anchorPeers, a.lastAnchorPeers)
rand.Seed(int64(randomUint32(16384)))
rand.Shuffle(len(anchorPeers), func(i, j int) {
anchorPeers[i], anchorPeers[j] = anchorPeers[j], anchorPeers[i]
})
for _, ka := range anchorPeers[:a.cfg.AnchorPeersCount] {
addresses = append(addresses, ka.Addr)
}
return addresses
}
// GetAddresses returns all the addresses currently found within the manager's address cache.
func (a *AddrBook) GetAddresses() []*AddrInfo {
a.mu.Lock()
defer a.mu.Unlock()
addrIndexLen := len(a.addrIndex)
if addrIndexLen == 0 {
return nil
}
addrs := make([]*AddrInfo, 0, addrIndexLen)
for _, v := range a.addrIndex {
addrs = append(addrs, v.Addr)
}
return addrs
}
// GetAllAddressesUsedBefore returns all the addresses used before the given time.
func (a *AddrBook) GetAllAddressesUsedBefore(date time.Time) []*AddrInfo {
a.mu.Lock()
defer a.mu.Unlock()
addrIndexLen := len(a.addrIndex)
if addrIndexLen == 0 {
return nil
}
addrs := make([]*AddrInfo, 0, addrIndexLen)
for _, v := range a.addrIndex {
if v.LastSeen.Before(date) {
addrs = append(addrs, v.Addr)
}
}
return addrs
}
// expireNew makes space in the new buckets by expiring the really bad entries.
// If no bad entries are available we look at a few and remove the oldest.
func (a *AddrBook) expireNew(bucket int) {
// First see if there are any entries that are so bad we can just throw
// them away. otherwise we throw away the oldest entry in the cache.
// Bitcoind here chooses four random and just throws the oldest of
// those away, but we keep track of oldest in the initial traversal and
// use that information instead.
var oldest *knownAddress
for k, v := range a.addrNew[bucket] {
if a.isBad(v) {
a.logger.Debug("expiring bad address %v", k)
delete(a.addrNew[bucket], k)
v.refs--
if v.refs == 0 {
a.nNew--
delete(a.addrIndex, k)
}
continue
}
if oldest == nil {
oldest = v
} else if !v.LastSeen.After(oldest.LastSeen) {
oldest = v
}
}
if oldest != nil {
key := oldest.Addr.ID
delete(a.addrNew[bucket], key)
oldest.refs--
if oldest.refs == 0 {
a.nNew--
delete(a.addrIndex, key)
}
}
}
func doubleHash(buf []byte) []byte {
first := hash.Sum(buf)
second := hash.Sum(first[:])
return second[:]
}
func (a *AddrBook) getNewBucket(netAddr, srcAddr net.IP) int {
// bitcoind:
// doublesha256(key + sourcegroup + int64(doublesha256(key + group + sourcegroup))%bucket_per_source_group) % num_new_buckets
var data1 []byte
data1 = append(data1, a.key[:]...)
data1 = append(data1, []byte(GroupKey(netAddr))...)
data1 = append(data1, []byte(GroupKey(srcAddr))...)
hash1 := doubleHash(data1)
hash64 := binary.LittleEndian.Uint64(hash1)
hash64 %= a.cfg.NewBucketsPerGroup
var hashbuf [8]byte
binary.LittleEndian.PutUint64(hashbuf[:], hash64)
var data2 []byte
data2 = append(data2, a.key[:]...)
data2 = append(data2, GroupKey(srcAddr)...)
data2 = append(data2, hashbuf[:]...)
hash2 := doubleHash(data2)
return int(binary.LittleEndian.Uint64(hash2) % a.cfg.NewBucketCount)
}
func (a *AddrBook) getTriedBucket(netAddr net.IP) int {
// bitcoind hashes this as:
// doublesha256(key + group + truncate_to_64bits(doublesha256(key)) % buckets_per_group) % num_buckets
var data1 []byte
data1 = append(data1, a.key[:]...)
data1 = append(data1, []byte(netAddr)...)
hash1 := doubleHash(data1)
hash64 := binary.LittleEndian.Uint64(hash1)
hash64 %= a.cfg.TriedBucketsPerGroup
var hashbuf [8]byte
binary.LittleEndian.PutUint64(hashbuf[:], hash64)
var data2 []byte
data2 = append(data2, a.key[:]...)
data2 = append(data2, GroupKey(netAddr)...)
data2 = append(data2, hashbuf[:]...)
hash2 := doubleHash(data2)
return int(binary.LittleEndian.Uint64(hash2) % a.cfg.TriedBucketCount)
}
// AddAddresses adds new addresses to the address manager. It enforces a max
// number of addresses and silently ignores duplicate addresses. It is
// safe for concurrent access.
func (a *AddrBook) AddAddresses(addrs []*AddrInfo, src *AddrInfo) {
a.mu.Lock()
defer a.mu.Unlock()
for _, na := range addrs {
a.updateAddress(na, src)
}
}
// AddAddress adds a new address to the address manager. It enforces a max
// number of addresses and silently ignores duplicate addresses. It is
// safe for concurrent access.
func (a *AddrBook) AddAddress(addr, src *AddrInfo) {
a.mu.Lock()
defer a.mu.Unlock()
a.updateAddress(addr, src)
}
// Attempt increases the given address' attempt counter and updates the last attempt time.
func (a *AddrBook) Attempt(pid peer.ID) {
a.mu.Lock()
defer a.mu.Unlock()
ka := a.lookup(pid)
if ka == nil {
return
}
ka.Attempts++
ka.LastAttempt = time.Now()
a.toTried(ka)
}
// Good marks the given address as good. To be called after a successful
// connection and version exchange. If the address is unknown to the address
// manager it will be ignored.
func (a *AddrBook) Good(pid peer.ID) {
a.mu.Lock()
defer a.mu.Unlock()
ka := a.lookup(pid)
if ka == nil {
return
}
now := time.Now()
ka.LastSuccess = now
ka.LastAttempt = now
ka.LastSeen = now
ka.Attempts = 0
a.toTried(ka)
}
// Connected adds the given address to anchor list. Will take some addresses this when node will start.
func (a *AddrBook) Connected(peerID peer.ID) {
a.mu.Lock()
defer a.mu.Unlock()
ka, ok := a.addrIndex[peerID]
if ok {
a.anchorPeers = append(a.anchorPeers, ka)
}
}
// RemoveAddress removes the address from the manager.
func (a *AddrBook) RemoveAddress(pid peer.ID) {
a.mu.Lock()
defer a.mu.Unlock()
if a.addrIndex[pid] == nil {
return
}
for _, b := range a.addrNew {
if _, ok := b[pid]; ok {
delete(b, pid)
a.nNew--
}
}
for _, b := range a.addrTried {
if _, ok := b[pid]; ok {
delete(b, pid)
a.nTried--
}
}
for i, ka := range a.anchorPeers {
if ka.Addr.ID == pid {
a.anchorPeers = append(a.anchorPeers[:i], a.anchorPeers[i+1:]...)
break
}
}
delete(a.addrIndex, pid)
}
// reset resets the address manager by reinitialising the random source and allocating fresh empty bucket storage.
func (a *AddrBook) reset() {
a.addrIndex = make(map[peer.ID]*knownAddress)
a.anchorPeers = make([]*knownAddress, 0)
a.lastAnchorPeers = make([]*knownAddress, 0)
a.addrNew = make([]map[peer.ID]*knownAddress, a.cfg.NewBucketCount)
a.addrTried = make([]map[peer.ID]*knownAddress, a.cfg.TriedBucketCount)
// fill key with bytes from a good random source.
if _, err := crand.Read(a.key[:]); err != nil {
a.logger.Panic("Error generating random bytes %v", err)
}
for i := range a.addrNew {
a.addrNew[i] = make(map[peer.ID]*knownAddress)
}
for i := range a.addrTried {
a.addrTried[i] = make(map[peer.ID]*knownAddress)
}
}
func randomUint32(max uint32) uint32 {
b := make([]byte, 4)
_, err := crand.Read(b)
if err != nil {
log.Panic("Failed to get entropy from system: ", err)
}
data := binary.BigEndian.Uint32(b)
return data % max
}