multi: add new config option to toggle gossip rate limiting

discovery/gossiper.go

@@ -228,6 +228,11 @@ type Config struct {
 	// This prevents ranges with old start times from causing us to dump the
 	// graph on connect.
 	IgnoreHistoricalFilters bool
+
+	// GossipUpdateThrottle if true, then the gossiper will throttle
+	// gossip updates to once per RebroadcastInterval for any keep-alive
+	// updates, and once per block for other types of updates.
+	GossipUpdateThrottle bool
 }
 
 // AuthenticatedGossiper is a subsystem which is responsible for receiving
@@ -1965,8 +1970,9 @@ func (d *AuthenticatedGossiper) processNetworkAnnouncement(
 
 		// If we have a previous version of the edge being updated,
 		// we'll want to rate limit its updates to prevent spam
-		// throughout the network.
-		if nMsg.isRemote && edgeToUpdate != nil {
+		// throughout the network if we're currently throttling such
+		// updates.
+		if d.cfg.GossipUpdateThrottle && nMsg.isRemote && edgeToUpdate != nil {
 			// If it's a keep-alive update, we'll only propagate one
 			// if it's been a day since the previous. This follows
 			// our own heuristic of sending keep-alive updates after

discovery/gossiper_test.go

@@ -3957,6 +3957,7 @@ func TestRateLimitChannelUpdates(t *testing.T) {
 	}
 	defer cleanup()
 	ctx.gossiper.cfg.RebroadcastInterval = time.Hour
+	ctx.gossiper.cfg.GossipUpdateThrottle = true
 
 	// The graph should start empty.
 	require.Empty(t, ctx.router.infos)

lncfg/protocol_legacy_off.go

@@ -20,3 +20,8 @@ func (l *LegacyProtocol) LegacyOnion() bool {
 func (l *LegacyProtocol) NoStaticRemoteKey() bool {
 	return false
 }
+
+// NoGossipThrottle returns true if gossip updates shouldn't be throttled.
+func (l *LegacyProtocol) NoGossipThrottle() bool {
+	return false
+}

lncfg/protocol_legacy_on.go

@@ -16,6 +16,12 @@ type LegacyProtocol struct {
 	// remote party's output in the commitment. If set to true, then we
 	// won't signal StaticRemoteKeyOptional.
 	CommitmentTweak bool `long:"committweak" description:"force node to not advertise the new commitment format"`
+
+	// NoGossipUpdateThrottle if true, then gossip updates won't be
+	// throttled using the current set of heuristics. This should mainly be
+	// used for integration tests where we want nearly instant propagation
+	// of gossip updates.
+	NoGossipUpdateThrottle bool `long:"no-gossip-throttle" description:"if true, then gossip updates will not be throttled to once per rebroadcast interval for non keep-alive updates"`
 }
 
 // LegacyOnion returns true if the old legacy onion format should be used when
@@ -30,3 +36,8 @@ func (l *LegacyProtocol) LegacyOnion() bool {
 func (l *LegacyProtocol) NoStaticRemoteKey() bool {
 	return l.CommitmentTweak
 }
+
+// NoGossipThrottle returns true if gossip updates shouldn't be throttled.
+func (l *LegacyProtocol) NoGossipThrottle() bool {
+	return l.NoGossipUpdateThrottle
+}

lntest/node.go

@@ -255,6 +255,7 @@ func (cfg NodeConfig) genArgs() []string {
 	args = append(args, fmt.Sprintf("--invoicemacaroonpath=%v", cfg.InvoiceMacPath))
 	args = append(args, fmt.Sprintf("--trickledelay=%v", trickleDelay))
 	args = append(args, fmt.Sprintf("--profile=%d", cfg.ProfilePort))
+	args = append(args, fmt.Sprintf("--protocol.legacy.no-gossip-throttle"))
 
 	if !cfg.HasSeed {
 		args = append(args, "--noseedbackup")

server.go

@@ -804,6 +804,7 @@ func newServer(cfg *Config, listenAddrs []net.Addr,
 		MinimumBatchSize:        10,
 		SubBatchDelay:           time.Second * 5,
 		IgnoreHistoricalFilters: cfg.IgnoreHistoricalGossipFilters,
+		GossipUpdateThrottle:    !cfg.ProtocolOptions.NoGossipThrottle(),
 	},
 		s.identityECDH.PubKey(),
 	)