Merge pull request #705 from libp2p/feat/static-relays

options to configure static relays for autorelay

config/config.go

@@ -76,6 +76,7 @@ type Config struct {
 	Routing RoutingC
 
 	EnableAutoRelay bool
+	StaticRelays    []peer.AddrInfo
 }
 
 // NewNode constructs a new libp2p Host from the Config.
@@ -231,7 +232,7 @@ func (cfg *Config) NewNode(ctx context.Context) (host.Host, error) {
 			// advertise ourselves
 			relay.Advertise(ctx, discovery)
 		} else {
-			_ = relay.NewAutoRelay(swrm.Context(), h, discovery, router)
+			_ = relay.NewAutoRelay(swrm.Context(), h, discovery, router, cfg.StaticRelays)
 		}
 	}
 

options.go

@@ -10,12 +10,14 @@ import (
 	"github.com/libp2p/go-libp2p-core/connmgr"
 	"github.com/libp2p/go-libp2p-core/crypto"
 	"github.com/libp2p/go-libp2p-core/metrics"
+	"github.com/libp2p/go-libp2p-core/peer"
 	"github.com/libp2p/go-libp2p-core/peerstore"
 	"github.com/libp2p/go-libp2p-core/pnet"
 
 	circuit "github.com/libp2p/go-libp2p-circuit"
 	config "github.com/libp2p/go-libp2p/config"
 	bhost "github.com/libp2p/go-libp2p/p2p/host/basic"
+	autorelay "github.com/libp2p/go-libp2p/p2p/host/relay"
 
 	filter "github.com/libp2p/go-maddr-filter"
 	ma "github.com/multiformats/go-multiaddr"
@@ -245,6 +247,35 @@ func EnableAutoRelay() Option {
 	}
 }
 
+// StaticRelays configures known relays for autorelay; when this option is enabled
+// then the system will use the configured relays instead of querying the DHT to
+// discover relays
+func StaticRelays(relays []peer.AddrInfo) Option {
+	return func(cfg *Config) error {
+		cfg.StaticRelays = append(cfg.StaticRelays, relays...)
+		return nil
+	}
+}
+
+// DefaultStaticRelays configures the static relays to use the known PL-operated relays
+func DefaultStaticRelays() Option {
+	return func(cfg *Config) error {
+		for _, addr := range autorelay.DefaultRelays {
+			a, err := ma.NewMultiaddr(addr)
+			if err != nil {
+				return err
+			}
+			pi, err := peer.AddrInfoFromP2pAddr(a)
+			if err != nil {
+				return err
+			}
+			cfg.StaticRelays = append(cfg.StaticRelays, *pi)
+		}
+
+		return nil
+	}
+}
+
 // FilterAddresses configures libp2p to never dial nor accept connections from
 // the given addresses. FilterAddresses should be used for cases where the
 // addresses you want to deny are known ahead of time.

p2p/host/relay/autorelay.go

@@ -25,11 +25,18 @@ const (
 )
 
 var (
-	DesiredRelays = 3
+	DesiredRelays = 1
 
 	BootDelay = 20 * time.Second
 )
 
+// These are the known PL-operated relays
+var DefaultRelays = []string{
+	"/ip4/147.75.80.110/tcp/4001/p2p/QmbFgm5zan8P6eWWmeyfncR5feYEMPbht5b1FW1C37aQ7y",
+	"/ip4/147.75.195.153/tcp/4001/p2p/QmW9m57aiBDHAkKj9nmFSEn7ZqrcF1fZS4bipsTCHburei",
+	"/ip4/147.75.70.221/tcp/4001/p2p/Qme8g49gm3q4Acp7xWBKg3nAa9fxZ1YmyDJdyGgoG6LsXh",
+}
+
 // AutoRelay is a Host that uses relays for connectivity when a NAT is detected.
 type AutoRelay struct {
 	host     *basic.BasicHost
@@ -38,6 +45,8 @@ type AutoRelay struct {
 	autonat  autonat.AutoNAT
 	addrsF   basic.AddrsFactory
 
+	static []peer.AddrInfo
+
 	disconnect chan struct{}
 
 	mx     sync.Mutex
@@ -48,12 +57,13 @@ type AutoRelay struct {
 	cachedAddrsExpiry time.Time
 }
 
-func NewAutoRelay(ctx context.Context, bhost *basic.BasicHost, discover discovery.Discoverer, router routing.PeerRouting) *AutoRelay {
+func NewAutoRelay(ctx context.Context, bhost *basic.BasicHost, discover discovery.Discoverer, router routing.PeerRouting, static []peer.AddrInfo) *AutoRelay {
 	ar := &AutoRelay{
 		host:       bhost,
 		discover:   discover,
 		router:     router,
 		addrsF:     bhost.AddrsFactory,
+		static:     static,
 		relays:     make(map[peer.ID]struct{}),
 		disconnect: make(chan struct{}, 1),
 		status:     autonat.NATStatusUnknown,
@@ -245,6 +255,10 @@ func (ar *AutoRelay) connect(ctx context.Context, pi peer.AddrInfo) bool {
 }
 
 func (ar *AutoRelay) discoverRelays(ctx context.Context) ([]peer.AddrInfo, error) {
+	if len(ar.static) > 0 {
+		return ar.static, nil
+	}
+
 	ctx, cancel := context.WithTimeout(ctx, 30*time.Second)
 	defer cancel()
 	return discovery.FindPeers(ctx, ar.discover, RelayRendezvous, discovery.Limit(1000))