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/
autorelay.go
293 lines (248 loc) · 6.93 KB
/
autorelay.go
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package relay
import (
"context"
"fmt"
"math/rand"
"sync"
"time"
basic "github.com/ipsn/go-ipfs/gxlibs/github.com/libp2p/go-libp2p/p2p/host/basic"
autonat "github.com/ipsn/go-ipfs/gxlibs/github.com/libp2p/go-libp2p-autonat"
_ "github.com/ipsn/go-ipfs/gxlibs/github.com/libp2p/go-libp2p-circuit"
discovery "github.com/ipsn/go-ipfs/gxlibs/github.com/libp2p/go-libp2p-discovery"
host "github.com/ipsn/go-ipfs/gxlibs/github.com/libp2p/go-libp2p-host"
inet "github.com/ipsn/go-ipfs/gxlibs/github.com/libp2p/go-libp2p-net"
peer "github.com/ipsn/go-ipfs/gxlibs/github.com/libp2p/go-libp2p-peer"
pstore "github.com/ipsn/go-ipfs/gxlibs/github.com/libp2p/go-libp2p-peerstore"
routing "github.com/ipsn/go-ipfs/gxlibs/github.com/libp2p/go-libp2p-routing"
ma "github.com/ipsn/go-ipfs/gxlibs/github.com/multiformats/go-multiaddr"
manet "github.com/ipsn/go-ipfs/gxlibs/github.com/multiformats/go-multiaddr-net"
)
const (
RelayRendezvous = "/libp2p/relay"
)
var (
DesiredRelays = 3
BootDelay = 60 * time.Second
unspecificRelay ma.Multiaddr
)
func init() {
var err error
unspecificRelay, err = ma.NewMultiaddr("/p2p-circuit")
if err != nil {
panic(err)
}
}
// AutoRelayHost is a Host that uses relays for connectivity when a NAT is detected.
type AutoRelayHost struct {
*basic.BasicHost
discover discovery.Discoverer
router routing.PeerRouting
autonat autonat.AutoNAT
addrsF basic.AddrsFactory
disconnect chan struct{}
mx sync.Mutex
relays map[peer.ID]pstore.PeerInfo
addrs []ma.Multiaddr
}
func NewAutoRelayHost(ctx context.Context, bhost *basic.BasicHost, discover discovery.Discoverer, router routing.PeerRouting) *AutoRelayHost {
h := &AutoRelayHost{
BasicHost: bhost,
discover: discover,
router: router,
addrsF: bhost.AddrsFactory,
relays: make(map[peer.ID]pstore.PeerInfo),
disconnect: make(chan struct{}, 1),
}
h.autonat = autonat.NewAutoNAT(ctx, bhost, h.baseAddrs)
bhost.AddrsFactory = h.hostAddrs
bhost.Network().Notify(h)
go h.background(ctx)
return h
}
func (h *AutoRelayHost) hostAddrs(addrs []ma.Multiaddr) []ma.Multiaddr {
h.mx.Lock()
defer h.mx.Unlock()
if h.addrs != nil && h.autonat.Status() == autonat.NATStatusPrivate {
return h.addrs
} else {
return filterUnspecificRelay(h.addrsF(addrs))
}
}
func (h *AutoRelayHost) baseAddrs() []ma.Multiaddr {
return filterUnspecificRelay(h.addrsF(h.AllAddrs()))
}
func (h *AutoRelayHost) background(ctx context.Context) {
select {
case <-time.After(autonat.AutoNATBootDelay + BootDelay):
case <-ctx.Done():
return
}
for {
wait := autonat.AutoNATRefreshInterval
switch h.autonat.Status() {
case autonat.NATStatusUnknown:
wait = autonat.AutoNATRetryInterval
case autonat.NATStatusPublic:
case autonat.NATStatusPrivate:
h.findRelays(ctx)
}
select {
case <-h.disconnect:
// invalidate addrs
h.mx.Lock()
h.addrs = nil
h.mx.Unlock()
case <-time.After(wait):
case <-ctx.Done():
return
}
}
}
func (h *AutoRelayHost) findRelays(ctx context.Context) {
h.mx.Lock()
if len(h.relays) >= DesiredRelays {
h.mx.Unlock()
return
}
need := DesiredRelays - len(h.relays)
h.mx.Unlock()
limit := 20
if need > limit/2 {
limit = 2 * need
}
dctx, cancel := context.WithTimeout(ctx, 60*time.Second)
pis, err := discovery.FindPeers(dctx, h.discover, RelayRendezvous, limit)
cancel()
if err != nil {
log.Debugf("error discovering relays: %s", err.Error())
return
}
pis = h.selectRelays(pis)
update := 0
for _, pi := range pis {
h.mx.Lock()
if _, ok := h.relays[pi.ID]; ok {
h.mx.Unlock()
continue
}
h.mx.Unlock()
cctx, cancel := context.WithTimeout(ctx, 60*time.Second)
if len(pi.Addrs) == 0 {
pi, err = h.router.FindPeer(cctx, pi.ID)
if err != nil {
log.Debugf("error finding relay peer %s: %s", pi.ID, err.Error())
cancel()
continue
}
}
err = h.Connect(cctx, pi)
cancel()
if err != nil {
log.Debugf("error connecting to relay %s: %s", pi.ID, err.Error())
continue
}
log.Debugf("connected to relay %s", pi.ID)
h.mx.Lock()
h.relays[pi.ID] = pi
h.mx.Unlock()
// tag the connection as very important
h.ConnManager().TagPeer(pi.ID, "relay", 42)
update++
need--
if need == 0 {
break
}
}
if update > 0 || h.addrs == nil {
h.updateAddrs()
}
}
func (h *AutoRelayHost) selectRelays(pis []pstore.PeerInfo) []pstore.PeerInfo {
// TODO better relay selection strategy; this just selects random relays
// but we should probably use ping latency as the selection metric
shuffleRelays(pis)
return pis
}
func (h *AutoRelayHost) updateAddrs() {
h.doUpdateAddrs()
h.PushIdentify()
}
// This function updates our NATed advertised addrs (h.addrs)
// The public addrs are rewritten so that they only retain the public IP part; they
// become undialable but are useful as a hint to the dialer to determine whether or not
// to dial private addrs.
// The non-public addrs are included verbatim so that peers behind the same NAT/firewall
// can still dial us directly.
// On top of those, we add the relay-specific addrs for the relays to which we are
// connected. For each non-private relay addr, we encapsulate the p2p-circuit addr
// through which we can be dialed.
func (h *AutoRelayHost) doUpdateAddrs() {
h.mx.Lock()
defer h.mx.Unlock()
addrs := h.baseAddrs()
raddrs := make([]ma.Multiaddr, 0, len(addrs)+len(h.relays))
// remove our public addresses from the list
for _, addr := range addrs {
if manet.IsPublicAddr(addr) {
continue
}
raddrs = append(raddrs, addr)
}
// add relay specific addrs to the list
for _, pi := range h.relays {
circuit, err := ma.NewMultiaddr(fmt.Sprintf("/p2p/%s/p2p-circuit", pi.ID.Pretty()))
if err != nil {
panic(err)
}
for _, addr := range pi.Addrs {
if !manet.IsPrivateAddr(addr) {
pub := addr.Encapsulate(circuit)
raddrs = append(raddrs, pub)
}
}
}
h.addrs = raddrs
}
func filterUnspecificRelay(addrs []ma.Multiaddr) []ma.Multiaddr {
res := make([]ma.Multiaddr, 0, len(addrs))
for _, addr := range addrs {
if addr.Equal(unspecificRelay) {
continue
}
res = append(res, addr)
}
return res
}
func shuffleRelays(pis []pstore.PeerInfo) {
for i := range pis {
j := rand.Intn(i + 1)
pis[i], pis[j] = pis[j], pis[i]
}
}
func containsAddr(lst []ma.Multiaddr, addr ma.Multiaddr) bool {
for _, xaddr := range lst {
if xaddr.Equal(addr) {
return true
}
}
return false
}
// notify
func (h *AutoRelayHost) Listen(inet.Network, ma.Multiaddr) {}
func (h *AutoRelayHost) ListenClose(inet.Network, ma.Multiaddr) {}
func (h *AutoRelayHost) Connected(inet.Network, inet.Conn) {}
func (h *AutoRelayHost) Disconnected(_ inet.Network, c inet.Conn) {
p := c.RemotePeer()
h.mx.Lock()
defer h.mx.Unlock()
if _, ok := h.relays[p]; ok {
delete(h.relays, p)
select {
case h.disconnect <- struct{}{}:
default:
}
}
}
func (h *AutoRelayHost) OpenedStream(inet.Network, inet.Stream) {}
func (h *AutoRelayHost) ClosedStream(inet.Network, inet.Stream) {}
var _ host.Host = (*AutoRelayHost)(nil)