go-libp2p-peerstore/addr_manager.go
2016-05-31 11:31:50 -07:00

315 lines
6.8 KiB
Go

package peerstore
import (
"sort"
"sync"
"time"
peer "github.com/ipfs/go-libp2p-peer"
addr "github.com/ipfs/go-libp2p-peerstore/addr"
ma "github.com/jbenet/go-multiaddr"
"golang.org/x/net/context"
)
const (
// TempAddrTTL is the ttl used for a short lived address
TempAddrTTL = time.Second * 10
// ProviderAddrTTL is the TTL of an address we've received from a provider.
// This is also a temporary address, but lasts longer. After this expires,
// the records we return will require an extra lookup.
ProviderAddrTTL = time.Minute * 10
// RecentlyConnectedAddrTTL is used when we recently connected to a peer.
// It means that we are reasonably certain of the peer's address.
RecentlyConnectedAddrTTL = time.Minute * 10
// OwnObservedAddrTTL is used for our own external addresses observed by peers.
OwnObservedAddrTTL = time.Minute * 10
// PermanentAddrTTL is the ttl for a "permanent address" (e.g. bootstrap nodes)
// if we haven't shipped you an update to ipfs in 356 days
// we probably arent running the same bootstrap nodes...
PermanentAddrTTL = time.Hour * 24 * 356
// ConnectedAddrTTL is the ttl used for the addresses of a peer to whom
// we're connected directly. This is basically permanent, as we will
// clear them + re-add under a TempAddrTTL after disconnecting.
ConnectedAddrTTL = PermanentAddrTTL
)
type expiringAddr struct {
Addr ma.Multiaddr
TTL time.Time
}
func (e *expiringAddr) ExpiredBy(t time.Time) bool {
return t.After(e.TTL)
}
type addrSet map[string]expiringAddr
// AddrManager manages addresses.
// The zero-value is ready to be used.
type AddrManager struct {
addrmu sync.Mutex // guards addrs
addrs map[peer.ID]addrSet
addrSubs map[peer.ID][]*addrSub
}
// ensures the AddrManager is initialized.
// So we can use the zero value.
func (mgr *AddrManager) init() {
if mgr.addrs == nil {
mgr.addrs = make(map[peer.ID]addrSet)
}
if mgr.addrSubs == nil {
mgr.addrSubs = make(map[peer.ID][]*addrSub)
}
}
func (mgr *AddrManager) Peers() []peer.ID {
mgr.addrmu.Lock()
defer mgr.addrmu.Unlock()
if mgr.addrs == nil {
return nil
}
pids := make([]peer.ID, 0, len(mgr.addrs))
for pid := range mgr.addrs {
pids = append(pids, pid)
}
return pids
}
// AddAddr calls AddAddrs(p, []ma.Multiaddr{addr}, ttl)
func (mgr *AddrManager) AddAddr(p peer.ID, addr ma.Multiaddr, ttl time.Duration) {
mgr.AddAddrs(p, []ma.Multiaddr{addr}, ttl)
}
// AddAddrs gives AddrManager 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 (mgr *AddrManager) AddAddrs(p peer.ID, addrs []ma.Multiaddr, ttl time.Duration) {
mgr.addrmu.Lock()
defer mgr.addrmu.Unlock()
// if ttl is zero, exit. nothing to do.
if ttl <= 0 {
return
}
// so zero value can be used
mgr.init()
amap, found := mgr.addrs[p]
if !found {
amap = make(addrSet)
mgr.addrs[p] = amap
}
subs := mgr.addrSubs[p]
// only expand ttls
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.TTL) {
amap[addrstr] = expiringAddr{Addr: addr, TTL: exp}
for _, sub := range subs {
sub.pubAddr(addr)
}
}
}
}
// SetAddr calls mgr.SetAddrs(p, addr, ttl)
func (mgr *AddrManager) SetAddr(p peer.ID, addr ma.Multiaddr, ttl time.Duration) {
mgr.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 (mgr *AddrManager) SetAddrs(p peer.ID, addrs []ma.Multiaddr, ttl time.Duration) {
mgr.addrmu.Lock()
defer mgr.addrmu.Unlock()
// so zero value can be used
mgr.init()
amap, found := mgr.addrs[p]
if !found {
amap = make(addrSet)
mgr.addrs[p] = amap
}
subs := mgr.addrSubs[p]
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.
addrs := string(addr.Bytes())
if ttl > 0 {
amap[addrs] = expiringAddr{Addr: addr, TTL: exp}
for _, sub := range subs {
sub.pubAddr(addr)
}
} else {
delete(amap, addrs)
}
}
}
// Addresses returns all known (and valid) addresses for a given
func (mgr *AddrManager) Addrs(p peer.ID) []ma.Multiaddr {
mgr.addrmu.Lock()
defer mgr.addrmu.Unlock()
// not initialized? nothing to give.
if mgr.addrs == nil {
return nil
}
maddrs, found := mgr.addrs[p]
if !found {
return nil
}
now := time.Now()
good := make([]ma.Multiaddr, 0, len(maddrs))
var expired []string
for s, m := range maddrs {
if m.ExpiredBy(now) {
expired = append(expired, s)
} else {
good = append(good, m.Addr)
}
}
// clean up the expired ones.
for _, s := range expired {
delete(maddrs, s)
}
return good
}
// ClearAddresses removes all previously stored addresses
func (mgr *AddrManager) ClearAddrs(p peer.ID) {
mgr.addrmu.Lock()
defer mgr.addrmu.Unlock()
mgr.init()
mgr.addrs[p] = make(addrSet) // clear what was there before
}
func (mgr *AddrManager) removeSub(p peer.ID, s *addrSub) {
mgr.addrmu.Lock()
defer mgr.addrmu.Unlock()
subs := mgr.addrSubs[p]
var filtered []*addrSub
for _, v := range subs {
if v != s {
filtered = append(filtered, v)
}
}
mgr.addrSubs[p] = filtered
}
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():
}
}
func (mgr *AddrManager) AddrStream(ctx context.Context, p peer.ID) <-chan ma.Multiaddr {
mgr.addrmu.Lock()
defer mgr.addrmu.Unlock()
mgr.init()
sub := &addrSub{pubch: make(chan ma.Multiaddr), ctx: ctx}
out := make(chan ma.Multiaddr)
mgr.addrSubs[p] = append(mgr.addrSubs[p], sub)
baseaddrset := mgr.addrs[p]
var initial []ma.Multiaddr
for _, a := range baseaddrset {
initial = append(initial, a.Addr)
}
sort.Sort(addr.AddrList(initial))
go func(buffer []ma.Multiaddr) {
defer close(out)
sent := make(map[string]bool)
var outch chan ma.Multiaddr
for _, a := range buffer {
sent[a.String()] = 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[naddr.String()] {
continue
}
sent[naddr.String()] = true
if next == nil {
next = naddr
outch = out
} else {
buffer = append(buffer, naddr)
}
case <-ctx.Done():
mgr.removeSub(p, sub)
return
}
}
}(initial)
return out
}