discovery: flag flip no historical gossip

config.go

@@ -308,6 +308,8 @@ type config struct {
 	NumGraphSyncPeers      int           `long:"numgraphsyncpeers" description:"The number of peers that we should receive new graph updates from. This option can be tuned to save bandwidth for light clients or routing nodes."`
 	HistoricalSyncInterval time.Duration `long:"historicalsyncinterval" description:"The polling interval between historical graph sync attempts. Each historical graph sync attempt ensures we reconcile with the remote peer's graph from the genesis block."`
 
+	IgnoreHistoricalGossipFilters bool `long:"ignore-historical-gossip-filters" description:"If true, will not reply with historical data that matches the range specified by a remote peer's gossip_timestamp_filter. Doing so will result in lower memory and bandwidth requirements."`
+
 	RejectPush bool `long:"rejectpush" description:"If true, lnd will not accept channel opening requests with non-zero push amounts. This should prevent accidental pushes to merchant nodes."`
 
 	StaggerInitialReconnect bool `long:"stagger-initial-reconnect" description:"If true, will apply a randomized staggering between 0s and 30s when reconnecting to persistent peers on startup. The first 10 reconnections will be attempted instantly, regardless of the flag's value"`

discovery/gossiper.go

@@ -211,6 +211,12 @@ type Config struct {
 	// SubBatchDelay is the delay between sending sub batches of
 	// gossip messages.
 	SubBatchDelay time.Duration
+
+	// IgnoreHistoricalFilters will prevent syncers from replying with
+	// historical data when the remote peer sets a gossip_timestamp_range.
+	// This prevents ranges with old start times from causing us to dump the
+	// graph on connect.
+	IgnoreHistoricalFilters bool
 }
 
 // AuthenticatedGossiper is a subsystem which is responsible for receiving
@@ -313,11 +319,12 @@ func New(cfg Config, selfKey *btcec.PublicKey) *AuthenticatedGossiper {
 		channelMtx:              multimutex.NewMutex(),
 		recentRejects:           make(map[uint64]struct{}),
 		syncMgr: newSyncManager(&SyncManagerCfg{
-			ChainHash:            cfg.ChainHash,
-			ChanSeries:           cfg.ChanSeries,
-			RotateTicker:         cfg.RotateTicker,
-			HistoricalSyncTicker: cfg.HistoricalSyncTicker,
-			NumActiveSyncers:     cfg.NumActiveSyncers,
+			ChainHash:               cfg.ChainHash,
+			ChanSeries:              cfg.ChanSeries,
+			RotateTicker:            cfg.RotateTicker,
+			HistoricalSyncTicker:    cfg.HistoricalSyncTicker,
+			NumActiveSyncers:        cfg.NumActiveSyncers,
+			IgnoreHistoricalFilters: cfg.IgnoreHistoricalFilters,
 		}),
 	}
 

discovery/sync_manager.go

@@ -82,6 +82,12 @@ type SyncManagerCfg struct {
 	// SyncManager when it should attempt a historical sync with a gossip
 	// sync peer.
 	HistoricalSyncTicker ticker.Ticker
+
+	// IgnoreHistoricalFilters will prevent syncers from replying with
+	// historical data when the remote peer sets a gossip_timestamp_range.
+	// This prevents ranges with old start times from causing us to dump the
+	// graph on connect.
+	IgnoreHistoricalFilters bool
 }
 
 // SyncManager is a subsystem of the gossiper that manages the gossip syncers
@@ -400,6 +406,7 @@ func (m *SyncManager) createGossipSyncer(peer lnpeer.Peer) *GossipSyncer {
 		sendToPeerSync: func(msgs ...lnwire.Message) error {
 			return peer.SendMessageLazy(true, msgs...)
 		},
+		ignoreHistoricalFilters: m.cfg.IgnoreHistoricalFilters,
 	})
 
 	// Gossip syncers are initialized by default in a PassiveSync type

discovery/syncer.go

@@ -235,6 +235,12 @@ type gossipSyncerCfg struct {
 	// replyHandler, meaning we will not reply to queries from our remote
 	// peer.
 	noReplyQueries bool
+
+	// ignoreHistoricalFilters will prevent syncers from replying with
+	// historical data when the remote peer sets a gossip_timestamp_range.
+	// This prevents ranges with old start times from causing us to dump the
+	// graph on connect.
+	ignoreHistoricalFilters bool
 }
 
 // GossipSyncer is a struct that handles synchronizing the channel graph state
@@ -951,6 +957,12 @@ func (g *GossipSyncer) ApplyGossipFilter(filter *lnwire.GossipTimestampRange) er
 
 	g.Unlock()
 
+	// If requested, don't reply with historical gossip data when the remote
+	// peer sets their gossip timestamp range.
+	if g.cfg.ignoreHistoricalFilters {
+		return nil
+	}
+
 	// Now that the remote peer has applied their filter, we'll query the
 	// database for all the messages that are beyond this filter.
 	newUpdatestoSend, err := g.cfg.channelSeries.UpdatesInHorizon(

discovery/syncer_test.go

@@ -1,8 +1,10 @@
 package discovery
 
 import (
+	"errors"
 	"math"
 	"reflect"
+	"sync"
 	"testing"
 	"time"
 
@@ -336,6 +338,66 @@ func TestGossipSyncerFilterGossipMsgsAllInMemory(t *testing.T) {
 	}
 }
 
+// TestGossipSyncerApplyNoHistoricalGossipFilter tests that once a gossip filter
+// is applied for the remote peer, then we don't send the peer all known
+// messages which are within their desired time horizon.
+func TestGossipSyncerApplyNoHistoricalGossipFilter(t *testing.T) {
+	t.Parallel()
+
+	// First, we'll create a GossipSyncer instance with a canned sendToPeer
+	// message to allow us to intercept their potential sends.
+	_, syncer, chanSeries := newTestSyncer(
+		lnwire.NewShortChanIDFromInt(10), defaultEncoding,
+		defaultChunkSize,
+	)
+	syncer.cfg.ignoreHistoricalFilters = true
+
+	// We'll apply this gossip horizon for the remote peer.
+	remoteHorizon := &lnwire.GossipTimestampRange{
+		FirstTimestamp: unixStamp(25000),
+		TimestampRange: uint32(1000),
+	}
+
+	// After applying the gossip filter, the chan series should not be
+	// queried using the updated horizon.
+	errChan := make(chan error, 1)
+	var wg sync.WaitGroup
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+
+		select {
+		// No query received, success.
+		case <-time.After(3 * time.Second):
+			errChan <- nil
+
+		// Unexpected query received.
+		case <-chanSeries.horizonReq:
+			errChan <- errors.New("chan series should not have been " +
+				"queried")
+		}
+	}()
+
+	// We'll now attempt to apply the gossip filter for the remote peer.
+	syncer.ApplyGossipFilter(remoteHorizon)
+
+	// Ensure that the syncer's remote horizon was properly updated.
+	if !reflect.DeepEqual(syncer.remoteUpdateHorizon, remoteHorizon) {
+		t.Fatalf("expected remote horizon: %v, got: %v",
+			remoteHorizon, syncer.remoteUpdateHorizon)
+	}
+
+	// Wait for the query check to finish.
+	wg.Wait()
+
+	// Assert that no query was made as a result of applying the gossip
+	// filter.
+	err := <-errChan
+	if err != nil {
+		t.Fatalf(err.Error())
+	}
+}
+
 // TestGossipSyncerApplyGossipFilter tests that once a gossip filter is applied
 // for the remote peer, then we send the peer all known messages which are
 // within their desired time horizon.

server.go

@@ -712,24 +712,25 @@ func newServer(listenAddrs []net.Addr, chanDB *channeldb.DB,
 	}
 
 	s.authGossiper = discovery.New(discovery.Config{
-		Router:               s.chanRouter,
-		Notifier:             s.cc.chainNotifier,
-		ChainHash:            *activeNetParams.GenesisHash,
-		Broadcast:            s.BroadcastMessage,
-		ChanSeries:           chanSeries,
-		NotifyWhenOnline:     s.NotifyWhenOnline,
-		NotifyWhenOffline:    s.NotifyWhenOffline,
-		ProofMatureDelta:     0,
-		TrickleDelay:         time.Millisecond * time.Duration(cfg.TrickleDelay),
-		RetransmitDelay:      time.Minute * 30,
-		WaitingProofStore:    waitingProofStore,
-		MessageStore:         gossipMessageStore,
-		AnnSigner:            s.nodeSigner,
-		RotateTicker:         ticker.New(discovery.DefaultSyncerRotationInterval),
-		HistoricalSyncTicker: ticker.New(cfg.HistoricalSyncInterval),
-		NumActiveSyncers:     cfg.NumGraphSyncPeers,
-		MinimumBatchSize:     10,
-		SubBatchDelay:        time.Second * 5,
+		Router:                  s.chanRouter,
+		Notifier:                s.cc.chainNotifier,
+		ChainHash:               *activeNetParams.GenesisHash,
+		Broadcast:               s.BroadcastMessage,
+		ChanSeries:              chanSeries,
+		NotifyWhenOnline:        s.NotifyWhenOnline,
+		NotifyWhenOffline:       s.NotifyWhenOffline,
+		ProofMatureDelta:        0,
+		TrickleDelay:            time.Millisecond * time.Duration(cfg.TrickleDelay),
+		RetransmitDelay:         time.Minute * 30,
+		WaitingProofStore:       waitingProofStore,
+		MessageStore:            gossipMessageStore,
+		AnnSigner:               s.nodeSigner,
+		RotateTicker:            ticker.New(discovery.DefaultSyncerRotationInterval),
+		HistoricalSyncTicker:    ticker.New(cfg.HistoricalSyncInterval),
+		NumActiveSyncers:        cfg.NumGraphSyncPeers,
+		MinimumBatchSize:        10,
+		SubBatchDelay:           time.Second * 5,
+		IgnoreHistoricalFilters: cfg.IgnoreHistoricalGossipFilters,
 	},
 		s.identityPriv.PubKey(),
 	)