From 77089ea4977b4af38e423a788d068bc9fdf68d36 Mon Sep 17 00:00:00 2001
From: Qishuai Liu <lqs@lqs.me>
Date: Tue, 6 May 2025 22:50:27 +0900
Subject: [PATCH 1/2] fix(ntp): prevent panic on NTP query error and add IPv6
 server in defaultNTPServers

---
 internal/timesync/ntp.go | 41 ++++++++++++++++++++--------------------
 1 file changed, 21 insertions(+), 20 deletions(-)

diff --git a/internal/timesync/ntp.go b/internal/timesync/ntp.go
index 41656b7..33340ed 100644
--- a/internal/timesync/ntp.go
+++ b/internal/timesync/ntp.go
@@ -13,7 +13,8 @@ var defaultNTPServers = []string{
 	"time.aws.com",
 	"time.windows.com",
 	"time.google.com",
-	"162.159.200.123", // time.cloudflare.com
+	"162.159.200.123",   // time.cloudflare.com IPv4
+	"2606:4700:f1::123", // time.cloudflare.com IPv6
 	"0.pool.ntp.org",
 	"1.pool.ntp.org",
 	"2.pool.ntp.org",
@@ -57,6 +58,12 @@ func (t *TimeSync) queryMultipleNTP(servers []string, timeout time.Duration) (no
 
 			// query the server
 			now, response, err := queryNtpServer(server, timeout)
+			if err != nil {
+				scopedLogger.Warn().
+					Str("error", err.Error()).
+					Msg("failed to query NTP server")
+				return
+			}
 
 			// set the last RTT
 			metricNtpServerLastRTT.WithLabelValues(
@@ -76,26 +83,20 @@ func (t *TimeSync) queryMultipleNTP(servers []string, timeout time.Duration) (no
 				strconv.Itoa(int(response.Precision)),
 			).Set(1)
 
-			if err == nil {
-				// increase success count
-				metricNtpTotalSuccessCount.Inc()
-				metricNtpSuccessCount.WithLabelValues(server).Inc()
+			// increase success count
+			metricNtpTotalSuccessCount.Inc()
+			metricNtpSuccessCount.WithLabelValues(server).Inc()
 
-				scopedLogger.Info().
-					Str("time", now.Format(time.RFC3339)).
-					Str("reference", response.ReferenceString()).
-					Str("rtt", response.RTT.String()).
-					Str("clockOffset", response.ClockOffset.String()).
-					Uint8("stratum", response.Stratum).
-					Msg("NTP server returned time")
-				results <- &ntpResult{
-					now:    now,
-					offset: &response.ClockOffset,
-				}
-			} else {
-				scopedLogger.Warn().
-					Str("error", err.Error()).
-					Msg("failed to query NTP server")
+			scopedLogger.Info().
+				Str("time", now.Format(time.RFC3339)).
+				Str("reference", response.ReferenceString()).
+				Str("rtt", response.RTT.String()).
+				Str("clockOffset", response.ClockOffset.String()).
+				Uint8("stratum", response.Stratum).
+				Msg("NTP server returned time")
+			results <- &ntpResult{
+				now:    now,
+				offset: &response.ClockOffset,
 			}
 		}(server)
 	}

From c13e1e11c5dbc0d11befdf096bb5a982c9b93a58 Mon Sep 17 00:00:00 2001
From: Qishuai Liu <lqs@lqs.me>
Date: Thu, 8 May 2025 11:31:40 +0900
Subject: [PATCH 2/2] fix(ntp): make sure queryMultipleNTP finish if all
 servers failed

---
 internal/timesync/ntp.go | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/internal/timesync/ntp.go b/internal/timesync/ntp.go
index 33340ed..d45112c 100644
--- a/internal/timesync/ntp.go
+++ b/internal/timesync/ntp.go
@@ -62,6 +62,7 @@ func (t *TimeSync) queryMultipleNTP(servers []string, timeout time.Duration) (no
 				scopedLogger.Warn().
 					Str("error", err.Error()).
 					Msg("failed to query NTP server")
+				results <- nil
 				return
 			}
 
@@ -101,8 +102,15 @@ func (t *TimeSync) queryMultipleNTP(servers []string, timeout time.Duration) (no
 		}(server)
 	}
 
-	result := <-results
-	return result.now, result.offset
+	for range servers {
+		result := <-results
+		if result == nil {
+			continue
+		}
+		now, offset = result.now, result.offset
+		return
+	}
+	return
 }
 
 func queryNtpServer(server string, timeout time.Duration) (now *time.Time, response *ntp.Response, err error) {