From 67df687f08a7c9674f38b42f5496d41b22448751 Mon Sep 17 00:00:00 2001
From: Elle Mouton <elle.mouton@gmail.com>
Date: Wed, 20 Sep 2023 10:44:11 +0200
Subject: [PATCH] discovery: start sending timestamps if requested

---
 discovery/chan_series.go | 13 ++++++++-----
 discovery/syncer.go      | 26 +++++++++++++++++++++++++-
 discovery/syncer_test.go |  3 ++-
 3 files changed, 35 insertions(+), 7 deletions(-)

diff --git a/discovery/chan_series.go b/discovery/chan_series.go
index 647d741a5..d0dc091d7 100644
--- a/discovery/chan_series.go
+++ b/discovery/chan_series.go
@@ -43,8 +43,8 @@ type ChannelGraphTimeSeries interface {
 	// between the start height and the end height. The channel IDs are
 	// grouped by their common block height. We'll use this to to a remote
 	// peer's QueryChannelRange message.
-	FilterChannelRange(chain chainhash.Hash,
-		startHeight, endHeight uint32) ([]channeldb.BlockChannelRange, error)
+	FilterChannelRange(chain chainhash.Hash, startHeight, endHeight uint32,
+		withTimestamps bool) ([]channeldb.BlockChannelRange, error)
 
 	// FetchChanAnns returns a full set of channel announcements as well as
 	// their updates that match the set of specified short channel ID's.
@@ -226,10 +226,13 @@ func (c *ChanSeries) FilterKnownChanIDs(chain chainhash.Hash,
 // message.
 //
 // NOTE: This is part of the ChannelGraphTimeSeries interface.
-func (c *ChanSeries) FilterChannelRange(chain chainhash.Hash,
-	startHeight, endHeight uint32) ([]channeldb.BlockChannelRange, error) {
+func (c *ChanSeries) FilterChannelRange(_ chainhash.Hash, startHeight,
+	endHeight uint32, withTimestamps bool) ([]channeldb.BlockChannelRange,
+	error) {
 
-	return c.graph.FilterChannelRange(startHeight, endHeight, false)
+	return c.graph.FilterChannelRange(
+		startHeight, endHeight, withTimestamps,
+	)
 }
 
 // FetchChanAnns returns a full set of channel announcements as well as their
diff --git a/discovery/syncer.go b/discovery/syncer.go
index 35368ddf6..6b0234dd7 100644
--- a/discovery/syncer.go
+++ b/discovery/syncer.go
@@ -1027,12 +1027,18 @@ func (g *GossipSyncer) replyChanRangeQuery(query *lnwire.QueryChannelRange) erro
 		"num_blocks=%v", g.cfg.peerPub[:], query.FirstBlockHeight,
 		query.NumBlocks)
 
+	// Check if the query asked for timestamps. We will only serve
+	// timestamps if this has not been disabled with
+	// noTimestampQueryOption.
+	withTimestamps := query.WithTimestamps() &&
+		!g.cfg.noTimestampQueryOption
+
 	// Next, we'll consult the time series to obtain the set of known
 	// channel ID's that match their query.
 	startBlock := query.FirstBlockHeight
 	endBlock := query.LastBlockHeight()
 	channelRanges, err := g.cfg.channelSeries.FilterChannelRange(
-		query.ChainHash, startBlock, endBlock,
+		query.ChainHash, startBlock, endBlock, withTimestamps,
 	)
 	if err != nil {
 		return err
@@ -1058,9 +1064,26 @@ func (g *GossipSyncer) replyChanRangeQuery(query *lnwire.QueryChannelRange) erro
 			complete = 1
 		}
 
+		var timestamps lnwire.Timestamps
+		if withTimestamps {
+			timestamps = make(lnwire.Timestamps, len(channelChunk))
+		}
+
 		scids := make([]lnwire.ShortChannelID, len(channelChunk))
 		for i, info := range channelChunk {
 			scids[i] = info.ShortChannelID
+
+			if !withTimestamps {
+				continue
+			}
+
+			timestamps[i].Timestamp1 = uint32(
+				info.Node1UpdateTimestamp.Unix(),
+			)
+
+			timestamps[i].Timestamp2 = uint32(
+				info.Node2UpdateTimestamp.Unix(),
+			)
 		}
 
 		return g.cfg.sendToPeerSync(&lnwire.ReplyChannelRange{
@@ -1070,6 +1093,7 @@ func (g *GossipSyncer) replyChanRangeQuery(query *lnwire.QueryChannelRange) erro
 			Complete:         complete,
 			EncodingType:     g.cfg.encodingType,
 			ShortChanIDs:     scids,
+			Timestamps:       timestamps,
 		})
 	}
 
diff --git a/discovery/syncer_test.go b/discovery/syncer_test.go
index 23fa2eb4e..3c7835107 100644
--- a/discovery/syncer_test.go
+++ b/discovery/syncer_test.go
@@ -98,7 +98,8 @@ func (m *mockChannelGraphTimeSeries) FilterKnownChanIDs(chain chainhash.Hash,
 	return <-m.filterResp, nil
 }
 func (m *mockChannelGraphTimeSeries) FilterChannelRange(chain chainhash.Hash,
-	startHeight, endHeight uint32) ([]channeldb.BlockChannelRange, error) {
+	startHeight, endHeight uint32, withTimestamps bool) (
+	[]channeldb.BlockChannelRange, error) {
 
 	m.filterRangeReqs <- filterRangeReq{startHeight, endHeight}
 	reply := <-m.filterRangeResp