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addr_book.go
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/
addr_book.go
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package pstoremem
import (
"context"
"sort"
"sync"
"time"
logging "github.com/ipfs/go-log"
peer "github.com/libp2p/go-libp2p-peer"
ma "github.com/multiformats/go-multiaddr"
pstore "github.com/libp2p/go-libp2p-peerstore"
addr "github.com/libp2p/go-libp2p-peerstore/addr"
)
var log = logging.Logger("peerstore")
type expiringAddr struct {
Addr ma.Multiaddr
TTL time.Duration
Expires time.Time
}
func (e *expiringAddr) ExpiredBy(t time.Time) bool {
return t.After(e.Expires)
}
var _ pstore.AddrBook = (*memoryAddrBook)(nil)
// memoryAddrBook manages addresses.
type memoryAddrBook struct {
addrmu sync.Mutex
// Use pointers to save memory. Maps always leave some fraction of their
// space unused. storing the *values* directly in the map will
// drastically increase the space waste. In our case, by 6x.
addrs map[peer.ID]map[string]*expiringAddr
nextGC time.Time
subManager *AddrSubManager
}
func NewAddrBook() pstore.AddrBook {
return &memoryAddrBook{
addrs: make(map[peer.ID]map[string]*expiringAddr),
subManager: NewAddrSubManager(),
}
}
// gc garbage collects the in-memory address book. The caller *must* hold the addrmu lock.
func (mab *memoryAddrBook) gc() {
now := time.Now()
if !now.After(mab.nextGC) {
return
}
for p, amap := range mab.addrs {
for k, addr := range amap {
if addr.ExpiredBy(now) {
delete(amap, k)
}
}
if len(amap) == 0 {
delete(mab.addrs, p)
}
}
mab.nextGC = time.Now().Add(pstore.AddressTTL)
}
func (mab *memoryAddrBook) PeersWithAddrs() peer.IDSlice {
mab.addrmu.Lock()
defer mab.addrmu.Unlock()
pids := make(peer.IDSlice, 0, len(mab.addrs))
for pid := range mab.addrs {
pids = append(pids, pid)
}
return pids
}
// AddAddr calls AddAddrs(p, []ma.Multiaddr{addr}, ttl)
func (mab *memoryAddrBook) AddAddr(p peer.ID, addr ma.Multiaddr, ttl time.Duration) {
mab.AddAddrs(p, []ma.Multiaddr{addr}, ttl)
}
// AddAddrs gives memoryAddrBook addresses to use, with a given ttl
// (time-to-live), after which the address is no longer valid.
// If the manager has a longer TTL, the operation is a no-op for that address
func (mab *memoryAddrBook) AddAddrs(p peer.ID, addrs []ma.Multiaddr, ttl time.Duration) {
mab.addrmu.Lock()
defer mab.addrmu.Unlock()
// if ttl is zero, exit. nothing to do.
if ttl <= 0 {
return
}
amap := mab.addrs[p]
if amap == nil {
amap = make(map[string]*expiringAddr, len(addrs))
mab.addrs[p] = amap
}
exp := time.Now().Add(ttl)
for _, addr := range addrs {
if addr == nil {
log.Warningf("was passed nil multiaddr for %s", p)
continue
}
addrstr := string(addr.Bytes())
a, found := amap[addrstr]
if !found || exp.After(a.Expires) {
amap[addrstr] = &expiringAddr{Addr: addr, Expires: exp, TTL: ttl}
mab.subManager.BroadcastAddr(p, addr)
}
}
mab.gc()
}
// SetAddr calls mgr.SetAddrs(p, addr, ttl)
func (mab *memoryAddrBook) SetAddr(p peer.ID, addr ma.Multiaddr, ttl time.Duration) {
mab.SetAddrs(p, []ma.Multiaddr{addr}, ttl)
}
// SetAddrs sets the ttl on addresses. This clears any TTL there previously.
// This is used when we receive the best estimate of the validity of an address.
func (mab *memoryAddrBook) SetAddrs(p peer.ID, addrs []ma.Multiaddr, ttl time.Duration) {
mab.addrmu.Lock()
defer mab.addrmu.Unlock()
amap := mab.addrs[p]
if amap == nil {
amap = make(map[string]*expiringAddr, len(addrs))
mab.addrs[p] = amap
}
exp := time.Now().Add(ttl)
for _, addr := range addrs {
if addr == nil {
log.Warningf("was passed nil multiaddr for %s", p)
continue
}
// re-set all of them for new ttl.
addrstr := string(addr.Bytes())
if ttl > 0 {
amap[addrstr] = &expiringAddr{Addr: addr, Expires: exp, TTL: ttl}
mab.subManager.BroadcastAddr(p, addr)
} else {
delete(amap, addrstr)
}
}
mab.gc()
}
// UpdateAddrs updates the addresses associated with the given peer that have
// the given oldTTL to have the given newTTL.
func (mab *memoryAddrBook) UpdateAddrs(p peer.ID, oldTTL time.Duration, newTTL time.Duration) {
mab.addrmu.Lock()
defer mab.addrmu.Unlock()
amap, found := mab.addrs[p]
if !found {
return
}
exp := time.Now().Add(newTTL)
for k, addr := range amap {
if oldTTL == addr.TTL {
addr.TTL = newTTL
addr.Expires = exp
amap[k] = addr
}
}
mab.gc()
}
// Addresses returns all known (and valid) addresses for a given
func (mab *memoryAddrBook) Addrs(p peer.ID) []ma.Multiaddr {
mab.addrmu.Lock()
defer mab.addrmu.Unlock()
amap, found := mab.addrs[p]
if !found {
return nil
}
now := time.Now()
good := make([]ma.Multiaddr, 0, len(amap))
for k, m := range amap {
if !m.ExpiredBy(now) {
good = append(good, m.Addr)
} else {
delete(amap, k)
}
}
return good
}
// ClearAddrs removes all previously stored addresses
func (mab *memoryAddrBook) ClearAddrs(p peer.ID) {
mab.addrmu.Lock()
defer mab.addrmu.Unlock()
delete(mab.addrs, p)
}
// AddrStream returns a channel on which all new addresses discovered for a
// given peer ID will be published.
func (mab *memoryAddrBook) AddrStream(ctx context.Context, p peer.ID) <-chan ma.Multiaddr {
mab.addrmu.Lock()
defer mab.addrmu.Unlock()
baseaddrslice := mab.addrs[p]
initial := make([]ma.Multiaddr, 0, len(baseaddrslice))
for _, a := range baseaddrslice {
initial = append(initial, a.Addr)
}
return mab.subManager.AddrStream(ctx, p, initial)
}
type addrSub struct {
pubch chan ma.Multiaddr
lk sync.Mutex
buffer []ma.Multiaddr
ctx context.Context
}
func (s *addrSub) pubAddr(a ma.Multiaddr) {
select {
case s.pubch <- a:
case <-s.ctx.Done():
}
}
// An abstracted, pub-sub manager for address streams. Extracted from
// memoryAddrBook in order to support additional implementations.
type AddrSubManager struct {
mu sync.RWMutex
subs map[peer.ID][]*addrSub
}
// NewAddrSubManager initializes an AddrSubManager.
func NewAddrSubManager() *AddrSubManager {
return &AddrSubManager{
subs: make(map[peer.ID][]*addrSub),
}
}
// Used internally by the address stream coroutine to remove a subscription
// from the manager.
func (mgr *AddrSubManager) removeSub(p peer.ID, s *addrSub) {
mgr.mu.Lock()
defer mgr.mu.Unlock()
subs := mgr.subs[p]
if len(subs) == 1 {
if subs[0] != s {
return
}
delete(mgr.subs, p)
return
}
for i, v := range subs {
if v == s {
subs[i] = subs[len(subs)-1]
subs[len(subs)-1] = nil
mgr.subs[p] = subs[:len(subs)-1]
return
}
}
}
// BroadcastAddr broadcasts a new address to all subscribed streams.
func (mgr *AddrSubManager) BroadcastAddr(p peer.ID, addr ma.Multiaddr) {
mgr.mu.RLock()
defer mgr.mu.RUnlock()
if subs, ok := mgr.subs[p]; ok {
for _, sub := range subs {
sub.pubAddr(addr)
}
}
}
// AddrStream creates a new subscription for a given peer ID, pre-populating the
// channel with any addresses we might already have on file.
func (mgr *AddrSubManager) AddrStream(ctx context.Context, p peer.ID, initial []ma.Multiaddr) <-chan ma.Multiaddr {
sub := &addrSub{pubch: make(chan ma.Multiaddr), ctx: ctx}
out := make(chan ma.Multiaddr)
mgr.mu.Lock()
if _, ok := mgr.subs[p]; ok {
mgr.subs[p] = append(mgr.subs[p], sub)
} else {
mgr.subs[p] = []*addrSub{sub}
}
mgr.mu.Unlock()
sort.Sort(addr.AddrList(initial))
go func(buffer []ma.Multiaddr) {
defer close(out)
sent := make(map[string]bool, len(buffer))
var outch chan ma.Multiaddr
for _, a := range buffer {
sent[string(a.Bytes())] = true
}
var next ma.Multiaddr
if len(buffer) > 0 {
next = buffer[0]
buffer = buffer[1:]
outch = out
}
for {
select {
case outch <- next:
if len(buffer) > 0 {
next = buffer[0]
buffer = buffer[1:]
} else {
outch = nil
next = nil
}
case naddr := <-sub.pubch:
if sent[string(naddr.Bytes())] {
continue
}
sent[string(naddr.Bytes())] = true
if next == nil {
next = naddr
outch = out
} else {
buffer = append(buffer, naddr)
}
case <-ctx.Done():
mgr.removeSub(p, sub)
return
}
}
}(initial)
return out
}