chore: cleanup ntp code

hub/executor/executor.go

@@ -231,6 +231,8 @@ func updateNTP(c *config.NTP) {
 			c.DialerProxy,
 			c.WriteToSystem,
 		)
+	} else {
+		ntp.ReCreateNTPService("", 0, "", false)
 	}
 }
 

ntp/service.go

@@ -3,6 +3,7 @@ package ntp
 import (
 	"context"
 	"sync"
+	"sync/atomic"
 	"time"
 
 	"github.com/metacubex/mihomo/component/dialer"
@@ -13,8 +14,8 @@ import (
 	"github.com/metacubex/sing/common/ntp"
 )
 
-var offset time.Duration
-var service *Service
+var globalSrv atomic.Pointer[Service]
+var globalMu sync.Mutex
 
 type Service struct {
 	server         M.Socksaddr
@@ -22,15 +23,20 @@ type Service struct {
 	ticker         *time.Ticker
 	ctx            context.Context
 	cancel         context.CancelFunc
-	mu             sync.Mutex
+	offset         atomic.Int64 // [time.Duration]
 	syncSystemTime bool
-	running        bool
 }
 
 func ReCreateNTPService(server string, interval time.Duration, dialerProxy string, syncSystemTime bool) {
+	globalMu.Lock()
+	defer globalMu.Unlock()
+	service := globalSrv.Swap(nil)
 	if service != nil {
 		service.Stop()
 	}
+	if server == "" {
+		return
+	}
 	ctx, cancel := context.WithCancel(context.Background())
 	service = &Service{
 		server:         M.ParseSocksaddr(server),
@@ -41,57 +47,43 @@ func ReCreateNTPService(server string, interval time.Duration, dialerProxy strin
 		syncSystemTime: syncSystemTime,
 	}
 	service.Start()
+	globalSrv.Store(service)
 }
 
 func (srv *Service) Start() {
-	srv.mu.Lock()
-	defer srv.mu.Unlock()
 	log.Infoln("NTP service start, sync system time is %t", srv.syncSystemTime)
-	err := srv.update()
-	if err != nil {
-		log.Errorln("Initialize NTP time failed: %s", err)
-		return
-	}
-	service.running = true
 	go srv.loopUpdate()
 }
 
 func (srv *Service) Stop() {
-	srv.mu.Lock()
-	defer srv.mu.Unlock()
-	if service.running {
-		srv.ticker.Stop()
 	srv.cancel()
-		service.running = false
-	}
 }
 
-func (srv *Service) Running() bool {
+func (srv *Service) Offset() time.Duration {
 	if srv == nil {
-		return false
+		return 0
 	}
-	srv.mu.Lock()
-	defer srv.mu.Unlock()
-	return srv.running
+	if srv.ctx.Err() != nil {
+		return time.Duration(srv.offset.Load())
+	}
+	return 0
 }
 
 func (srv *Service) update() error {
 	var response *ntp.Response
 	var err error
 	for i := 0; i < 3; i++ {
-		if response, err = ntp.Exchange(context.Background(), srv.dialer, srv.server); err == nil {
-			break
+		response, err = ntp.Exchange(srv.ctx, srv.dialer, srv.server)
+		if err != nil {
+			continue
 		}
-		if i == 2 {
-			return err
-		}
-	}
-	offset = response.ClockOffset
+		offset := response.ClockOffset
 		if offset > time.Duration(0) {
 			log.Infoln("System clock is ahead of NTP time by %s", offset)
 		} else if offset < time.Duration(0) {
 			log.Infoln("System clock is behind NTP time by %s", -offset)
 		}
+		srv.offset.Store(int64(offset))
 		if srv.syncSystemTime {
 			timeNow := response.Time
 			syncErr := setSystemTime(timeNow)
@@ -103,25 +95,28 @@ func (srv *Service) update() error {
 			}
 		}
 		return nil
+	}
+	return err
 }
 
 func (srv *Service) loopUpdate() {
+	defer srv.ticker.Stop()
 	for {
+		err := srv.update()
+		if err != nil {
+			log.Warnln("Sync time failed: %s", err)
+		}
 		select {
 		case <-srv.ctx.Done():
 			return
 		case <-srv.ticker.C:
 		}
-		err := srv.update()
-		if err != nil {
-			log.Warnln("Sync time failed: %s", err)
-		}
 	}
 }
 
 func Now() time.Time {
 	now := time.Now()
-	if service.Running() && offset.Abs() > 0 {
+	if offset := globalSrv.Load().Offset(); offset.Abs() > 0 {
 		now = now.Add(offset)
 	}
 	return now