From 85f4b13632f7579149f83593cf1ccc73da4c13f7 Mon Sep 17 00:00:00 2001
From: yyforyongyu <yy2452@columbia.edu>
Date: Wed, 22 Nov 2023 23:12:49 +0800
Subject: [PATCH] multi: enhance logging around channel reestablishment

---
 channeldb/channel.go | 36 ++++++++++++++++++++++++++++++++++++
 htlcswitch/link.go   |  5 +++--
 peer/brontide.go     |  3 ++-
 3 files changed, 41 insertions(+), 3 deletions(-)

diff --git a/channeldb/channel.go b/channeldb/channel.go
index 67a32379e..dbd796c87 100644
--- a/channeldb/channel.go
+++ b/channeldb/channel.go
@@ -849,6 +849,30 @@ type OpenChannel struct {
 	sync.RWMutex
 }
 
+// String returns a string representation of the channel.
+func (c *OpenChannel) String() string {
+	indexStr := "height=%v, local_htlc_index=%v, local_log_index=%v, " +
+		"remote_htlc_index=%v, remote_log_index=%v"
+
+	commit := c.LocalCommitment
+	local := fmt.Sprintf(indexStr, commit.CommitHeight,
+		commit.LocalHtlcIndex, commit.LocalLogIndex,
+		commit.RemoteHtlcIndex, commit.RemoteLogIndex,
+	)
+
+	commit = c.RemoteCommitment
+	remote := fmt.Sprintf(indexStr, commit.CommitHeight,
+		commit.LocalHtlcIndex, commit.LocalLogIndex,
+		commit.RemoteHtlcIndex, commit.RemoteLogIndex,
+	)
+
+	return fmt.Sprintf("SCID=%v, status=%v, initiator=%v, pending=%v, "+
+		"local commitment has %s, remote commitment has %s",
+		c.ShortChannelID, c.chanStatus, c.IsInitiator, c.IsPending,
+		local, remote,
+	)
+}
+
 // ShortChanID returns the current ShortChannelID of this channel.
 func (c *OpenChannel) ShortChanID() lnwire.ShortChannelID {
 	c.RLock()
@@ -2100,6 +2124,10 @@ func (c *OpenChannel) ActiveHtlcs() []HTLC {
 	// which ones are present on their commitment.
 	remoteHtlcs := make(map[[32]byte]struct{})
 	for _, htlc := range c.RemoteCommitment.Htlcs {
+		log.Tracef("RemoteCommitment has htlc: id=%v, update=%v "+
+			"incoming=%v", htlc.HtlcIndex, htlc.LogIndex,
+			htlc.Incoming)
+
 		onionHash := sha256.Sum256(htlc.OnionBlob[:])
 		remoteHtlcs[onionHash] = struct{}{}
 	}
@@ -2108,8 +2136,16 @@ func (c *OpenChannel) ActiveHtlcs() []HTLC {
 	// as active if *we* know them as well.
 	activeHtlcs := make([]HTLC, 0, len(remoteHtlcs))
 	for _, htlc := range c.LocalCommitment.Htlcs {
+		log.Tracef("LocalCommitment has htlc: id=%v, update=%v "+
+			"incoming=%v", htlc.HtlcIndex, htlc.LogIndex,
+			htlc.Incoming)
+
 		onionHash := sha256.Sum256(htlc.OnionBlob[:])
 		if _, ok := remoteHtlcs[onionHash]; !ok {
+			log.Tracef("Skipped htlc due to onion mismatched: "+
+				"id=%v, update=%v incoming=%v",
+				htlc.HtlcIndex, htlc.LogIndex, htlc.Incoming)
+
 			continue
 		}
 
diff --git a/htlcswitch/link.go b/htlcswitch/link.go
index 2a1e49923..e302cf3d8 100644
--- a/htlcswitch/link.go
+++ b/htlcswitch/link.go
@@ -649,12 +649,13 @@ func (l *channelLink) createFailureWithUpdate(incoming bool,
 // flow. We'll compare out commitment chains with the remote party, and re-send
 // either a danging commit signature, a revocation, or both.
 func (l *channelLink) syncChanStates() error {
-	l.log.Info("attempting to re-synchronize")
+	chanState := l.channel.State()
+
+	l.log.Infof("Attempting to re-synchronize channel: %v", chanState)
 
 	// First, we'll generate our ChanSync message to send to the other
 	// side. Based on this message, the remote party will decide if they
 	// need to retransmit any data or not.
-	chanState := l.channel.State()
 	localChanSyncMsg, err := chanState.ChanSyncMsg()
 	if err != nil {
 		return fmt.Errorf("unable to generate chan sync message for "+
diff --git a/peer/brontide.go b/peer/brontide.go
index d7d93f4fa..35cdbd847 100644
--- a/peer/brontide.go
+++ b/peer/brontide.go
@@ -2009,7 +2009,8 @@ func messageSummary(msg lnwire.Message) string {
 			msg.ChanID, int64(msg.FeePerKw))
 
 	case *lnwire.ChannelReestablish:
-		return fmt.Sprintf("next_local_height=%v, remote_tail_height=%v",
+		return fmt.Sprintf("chan_id=%v, next_local_height=%v, "+
+			"remote_tail_height=%v", msg.ChanID,
 			msg.NextLocalCommitHeight, msg.RemoteCommitTailHeight)
 
 	case *lnwire.ReplyShortChanIDsEnd: