autonatv2: implement autonatv2 spec

config/config.go

@@ -24,6 +24,7 @@ import (
 	"github.com/libp2p/go-libp2p/p2p/host/autonat"
 	"github.com/libp2p/go-libp2p/p2p/host/autorelay"
 	bhost "github.com/libp2p/go-libp2p/p2p/host/basic"
+	blankhost "github.com/libp2p/go-libp2p/p2p/host/blank"
 	"github.com/libp2p/go-libp2p/p2p/host/eventbus"
 	"github.com/libp2p/go-libp2p/p2p/host/peerstore/pstoremem"
 	rcmgr "github.com/libp2p/go-libp2p/p2p/host/resource-manager"
@@ -131,6 +132,8 @@ type Config struct {
 	SwarmOpts []swarm.Option
 
 	DisableIdentifyAddressDiscovery bool
+
+	DisableAutoNATv2 bool
 }
 
 func (cfg *Config) makeSwarm(eventBus event.Bus, enableMetrics bool) (*swarm.Swarm, error) {
@@ -193,6 +196,76 @@ func (cfg *Config) makeSwarm(eventBus event.Bus, enableMetrics bool) (*swarm.Swa
 	return swarm.NewSwarm(pid, cfg.Peerstore, eventBus, opts...)
 }
 
+func (cfg *Config) makeAutoNATHost() (host.Host, error) {
+	autonatPrivKey, _, err := crypto.GenerateEd25519Key(rand.Reader)
+	if err != nil {
+		return nil, err
+	}
+	ps, err := pstoremem.NewPeerstore()
+	if err != nil {
+		return nil, err
+	}
+
+	autoNatCfg := Config{
+		Transports:         cfg.Transports,
+		Muxers:             cfg.Muxers,
+		SecurityTransports: cfg.SecurityTransports,
+		Insecure:           cfg.Insecure,
+		PSK:                cfg.PSK,
+		ConnectionGater:    cfg.ConnectionGater,
+		Reporter:           cfg.Reporter,
+		PeerKey:            autonatPrivKey,
+		Peerstore:          ps,
+		DialRanker:         swarm.NoDelayDialRanker,
+		SwarmOpts: []swarm.Option{
+			// Disable black hole detection on autonat dialers
+			// It is better to attempt a dial and fail for AutoNAT use cases
+			swarm.WithUDPBlackHoleConfig(false, 0, 0),
+			swarm.WithIPv6BlackHoleConfig(false, 0, 0),
+		},
+	}
+	fxopts, err := autoNatCfg.addTransports()
+	if err != nil {
+		return nil, err
+	}
+	var dialerHost host.Host
+	fxopts = append(fxopts,
+		fx.Provide(eventbus.NewBus),
+		fx.Provide(func(lifecycle fx.Lifecycle, b event.Bus) (*swarm.Swarm, error) {
+			lifecycle.Append(fx.Hook{
+				OnStop: func(context.Context) error {
+					return ps.Close()
+				}})
+			sw, err := autoNatCfg.makeSwarm(b, false)
+			return sw, err
+		}),
+		fx.Provide(func(sw *swarm.Swarm) *blankhost.BlankHost {
+			return blankhost.NewBlankHost(sw)
+		}),
+		fx.Provide(func(bh *blankhost.BlankHost) host.Host {
+			return bh
+		}),
+		fx.Provide(func() crypto.PrivKey { return autonatPrivKey }),
+		fx.Provide(func(bh host.Host) peer.ID { return bh.ID() }),
+		fx.Invoke(func(bh *blankhost.BlankHost) {
+			dialerHost = bh
+		}),
+	)
+	app := fx.New(fxopts...)
+	if err := app.Err(); err != nil {
+		return nil, err
+	}
+	err = app.Start(context.Background())
+	if err != nil {
+		return nil, err
+	}
+	go func() {
+		<-dialerHost.Network().(*swarm.Swarm).Done()
+		app.Stop(context.Background())
+	}()
+	return dialerHost, nil
+}
+
 func (cfg *Config) addTransports() ([]fx.Option, error) {
 	fxopts := []fx.Option{
 		fx.WithLogger(func() fxevent.Logger { return getFXLogger() }),
@@ -291,6 +364,14 @@ func (cfg *Config) addTransports() ([]fx.Option, error) {
 }
 
 func (cfg *Config) newBasicHost(swrm *swarm.Swarm, eventBus event.Bus) (*bhost.BasicHost, error) {
+	var autonatv2Dialer host.Host
+	if !cfg.DisableAutoNATv2 {
+		ah, err := cfg.makeAutoNATHost()
+		if err != nil {
+			return nil, err
+		}
+		autonatv2Dialer = ah
+	}
 	h, err := bhost.NewHost(swrm, &bhost.HostOpts{
 		EventBus:                        eventBus,
 		ConnManager:                     cfg.ConnManager,
@@ -306,6 +387,8 @@ func (cfg *Config) newBasicHost(swrm *swarm.Swarm, eventBus event.Bus) (*bhost.B
 		EnableMetrics:                   !cfg.DisableMetrics,
 		PrometheusRegisterer:            cfg.PrometheusRegisterer,
 		DisableIdentifyAddressDiscovery: cfg.DisableIdentifyAddressDiscovery,
+		EnableAutoNATv2:                 !cfg.DisableAutoNATv2,
+		AutoNATv2Dialer:                 autonatv2Dialer,
 	})
 	if err != nil {
 		return nil, err

core/network/network.go

@@ -161,6 +161,20 @@ type Network interface {
 	ResourceManager() ResourceManager
 }
 
+// Dialability indicates how dialable a (peer, addr) combination is.
+type Dialability int
+
+const (
+	// DialabilityUnknown indicates that the dialer cannot dial the (peer, addr) combination
+	DialabilityUnknown Dialability = iota
+
+	// DialabilityDialable indicates that the dialer can dial the (peer, addr) combination
+	DialabilityDialable
+
+	// DialabilityUndialable indicates that the dialer cannot dial the (peer, addr) combinaton
+	DialabilityUndialable
+)
+
 // Dialer represents a service that can dial out to peers
 // (this is usually just a Network, but other services may not need the whole
 // stack, and thus it becomes easier to mock)
@@ -194,6 +208,9 @@ type Dialer interface {
 	// Notify/StopNotify register and unregister a notifiee for signals
 	Notify(Notifiee)
 	StopNotify(Notifiee)
+
+	// CanDial returns whether the dialer can dial peer p at addr
+	CanDial(p peer.ID, addr ma.Multiaddr) Dialability
 }
 
 // AddrDelay provides an address along with the delay after which the address

options.go

@@ -609,3 +609,11 @@ func DisableIdentifyAddressDiscovery() Option {
 		return nil
 	}
 }
+
+// DisableAutoNATv2 disables autonat
+func DisableAutoNATv2() Option {
+	return func(cfg *Config) error {
+		cfg.DisableAutoNATv2 = true
+		return nil
+	}
+}

p2p/host/basic/basic_host.go

@@ -24,6 +24,7 @@ import (
 	"github.com/libp2p/go-libp2p/p2p/host/eventbus"
 	"github.com/libp2p/go-libp2p/p2p/host/pstoremanager"
 	"github.com/libp2p/go-libp2p/p2p/host/relaysvc"
+	"github.com/libp2p/go-libp2p/p2p/protocol/autonatv2"
 	relayv2 "github.com/libp2p/go-libp2p/p2p/protocol/circuitv2/relay"
 	"github.com/libp2p/go-libp2p/p2p/protocol/holepunch"
 	"github.com/libp2p/go-libp2p/p2p/protocol/identify"
@@ -105,6 +106,8 @@ type BasicHost struct {
 	caBook                  peerstore.CertifiedAddrBook
 
 	autoNat autonat.AutoNAT
+
+	autonatv2 *autonatv2.AutoNAT
 }
 
 var _ host.Host = (*BasicHost)(nil)
@@ -167,6 +170,8 @@ type HostOpts struct {
 
 	// DisableIdentifyAddressDiscovery disables address discovery using peer provided observed addresses in identify
 	DisableIdentifyAddressDiscovery bool
+	EnableAutoNATv2                 bool
+	AutoNATv2Dialer                 host.Host
 }
 
 // NewHost constructs a new *BasicHost and activates it by attaching its stream and connection handlers to the given inet.Network.
@@ -310,6 +315,13 @@ func NewHost(n network.Network, opts *HostOpts) (*BasicHost, error) {
 		h.pings = ping.NewPingService(h)
 	}
 
+	if opts.EnableAutoNATv2 {
+		h.autonatv2, err = autonatv2.New(h, opts.AutoNATv2Dialer)
+		if err != nil {
+			return nil, fmt.Errorf("failed to create autonatv2: %w", err)
+		}
+	}
+
 	n.SetStreamHandler(h.newStreamHandler)
 
 	// register to be notified when the network's listen addrs change,
@@ -1100,6 +1112,9 @@ func (h *BasicHost) Close() error {
 		if h.hps != nil {
 			h.hps.Close()
 		}
+		if h.autonatv2 != nil {
+			h.autonatv2.Close()
+		}
 
 		_ = h.emitters.evtLocalProtocolsUpdated.Close()
 		_ = h.emitters.evtLocalAddrsUpdated.Close()

p2p/net/mock/mock_peernet.go

@@ -434,3 +434,7 @@ func (pn *peernet) notifyAll(notification func(f network.Notifiee)) {
 func (pn *peernet) ResourceManager() network.ResourceManager {
 	return &network.NullResourceManager{}
 }
+
+func (pn *peernet) CanDial(p peer.ID, addr ma.Multiaddr) network.Dialability {
+	return network.DialabilityUnknown
+}

p2p/net/swarm/black_hole_detector.go

@@ -144,6 +144,13 @@ func (b *blackHoleFilter) updateState() {
 	}
 }
 
+func (b *blackHoleFilter) State() blackHoleState {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+
+	return b.state
+}
+
 func (b *blackHoleFilter) trackMetrics() {
 	if b.metricsTracer == nil {
 		return
@@ -244,6 +251,27 @@ func (d *blackHoleDetector) RecordResult(addr ma.Multiaddr, success bool) {
 	}
 }
 
+func (d *blackHoleDetector) State(addr ma.Multiaddr) blackHoleState {
+	if !manet.IsPublicAddr(addr) {
+		return blackHoleStateAllowed
+	}
+
+	if d.udp != nil && isProtocolAddr(addr, ma.P_UDP) {
+		udpState := d.udp.State()
+		if udpState != blackHoleStateAllowed {
+			return udpState
+		}
+	}
+
+	if d.ipv6 != nil && isProtocolAddr(addr, ma.P_IP6) {
+		ipv6State := d.ipv6.State()
+		if ipv6State != blackHoleStateAllowed {
+			return ipv6State
+		}
+	}
+	return blackHoleStateAllowed
+}
+
 // blackHoleConfig is the config used for black hole detection
 type blackHoleConfig struct {
 	// Enabled enables black hole detection

p2p/net/swarm/black_hole_detector_test.go

@@ -17,6 +17,9 @@ func TestBlackHoleFilterReset(t *testing.T) {
 		if bhf.HandleRequest() != blackHoleResultProbing {
 			t.Fatalf("expected calls up to n to be probes")
 		}
+		if bhf.State() != blackHoleStateProbing {
+			t.Fatalf("expected state to be probing got %s", bhf.State())
+		}
 		bhf.RecordResult(false)
 	}
 
@@ -26,6 +29,9 @@ func TestBlackHoleFilterReset(t *testing.T) {
 		if (i%n == 0 && result != blackHoleResultProbing) || (i%n != 0 && result != blackHoleResultBlocked) {
 			t.Fatalf("expected every nth dial to be a probe")
 		}
+		if bhf.State() != blackHoleStateBlocked {
+			t.Fatalf("expected state to be blocked, got %s", bhf.State())
+		}
 	}
 
 	bhf.RecordResult(true)
@@ -34,12 +40,18 @@ func TestBlackHoleFilterReset(t *testing.T) {
 		if bhf.HandleRequest() != blackHoleResultProbing {
 			t.Fatalf("expected black hole detector state to reset after success")
 		}
+		if bhf.State() != blackHoleStateProbing {
+			t.Fatalf("expected state to be probing got %s", bhf.State())
+		}
 		bhf.RecordResult(false)
 	}
 
 	// next call should be blocked
 	if bhf.HandleRequest() != blackHoleResultBlocked {
 		t.Fatalf("expected dial to be blocked")
+		if bhf.State() != blackHoleStateBlocked {
+			t.Fatalf("expected state to be blocked, got %s", bhf.State())
+		}
 	}
 }
 

p2p/net/swarm/swarm.go

@@ -112,7 +112,7 @@ func WithDialRanker(d network.DialRanker) Option {
 	}
 }
 
-// WithUDPBlackHoleConfig configures swarm to use c as the config for UDP black hole detection
+// WithUDPBlackHoleConfig configures swarm to use the provided config for UDP black hole detection
 // n is the size of the sliding window used to evaluate black hole state
 // min is the minimum number of successes out of n required to not block requests
 func WithUDPBlackHoleConfig(enabled bool, n, min int) Option {
@@ -122,7 +122,7 @@ func WithUDPBlackHoleConfig(enabled bool, n, min int) Option {
 	}
 }
 
-// WithIPv6BlackHoleConfig configures swarm to use c as the config for IPv6 black hole detection
+// WithIPv6BlackHoleConfig configures swarm to use the provided config for IPv6 black hole detection
 // n is the size of the sliding window used to evaluate black hole state
 // min is the minimum number of successes out of n required to not block requests
 func WithIPv6BlackHoleConfig(enabled bool, n, min int) Option {

p2p/net/swarm/swarm_dial.go

@@ -416,6 +416,26 @@ func (s *Swarm) dialNextAddr(ctx context.Context, p peer.ID, addr ma.Multiaddr,
 	return nil
 }
 
+func (s *Swarm) CanDial(p peer.ID, addr ma.Multiaddr) network.Dialability {
+	dialable, _ := s.filterKnownUndialables(p, []ma.Multiaddr{addr})
+	if len(dialable) == 0 {
+		return network.DialabilityUndialable
+	}
+
+	bhState := s.bhd.State(addr)
+	switch bhState {
+	case blackHoleStateAllowed:
+		return network.DialabilityDialable
+	case blackHoleStateProbing:
+		return network.DialabilityUnknown
+	case blackHoleStateBlocked:
+		return network.DialabilityUndialable
+	default:
+		log.Errorf("SWARM BUG: unhandled black hole state for dilability check %s", bhState)
+		return network.DialabilityUnknown
+	}
+}
+
 func (s *Swarm) nonProxyAddr(addr ma.Multiaddr) bool {
 	t := s.TransportForDialing(addr)
 	return !t.Proxy()