!WIP! router_timestamper

go.mod

@@ -5,6 +5,7 @@ go 1.22
 toolchain go1.22.5
 
 require (
+	github.com/beevik/ntp v1.4.3
 	github.com/eyedeekay/go-unzip v0.0.0-20240201194209-560d8225b50e
 	github.com/flynn/noise v1.1.0
 	github.com/sirupsen/logrus v1.9.3
@@ -17,6 +18,7 @@ require (
 	filippo.io/edwards25519 v1.1.0 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
+	golang.org/x/net v0.28.0 // indirect
 	golang.org/x/sys v0.24.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

go.sum

@@ -1,5 +1,7 @@
 filippo.io/edwards25519 v1.1.0 h1:FNf4tywRC1HmFuKW5xopWpigGjJKiJSV0Cqo0cJWDaA=
 filippo.io/edwards25519 v1.1.0/go.mod h1:BxyFTGdWcka3PhytdK4V28tE5sGfRvvvRV7EaN4VDT4=
+github.com/beevik/ntp v1.4.3 h1:PlbTvE5NNy4QHmA4Mg57n7mcFTmr1W1j3gcK7L1lqho=
+github.com/beevik/ntp v1.4.3/go.mod h1:Unr8Zg+2dRn7d8bHFuehIMSvvUYssHMxW3Q5Nx4RW5Q=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
@@ -26,6 +28,8 @@ golang.org/x/crypto v0.0.0-20210322153248-0c34fe9e7dc2/go.mod h1:T9bdIzuCu7OtxOm
 golang.org/x/crypto v0.26.0 h1:RrRspgV4mU+YwB4FYnuBoKsUapNIL5cohGAmSH3azsw=
 golang.org/x/crypto v0.26.0/go.mod h1:GY7jblb9wI+FOo5y8/S2oY4zWP07AkOJ4+jxCqdqn54=
 golang.org/x/net v0.0.0-20210226172049-e18ecbb05110/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
+golang.org/x/net v0.28.0 h1:a9JDOJc5GMUJ0+UDqmLT86WiEy7iWyIhz8gz8E4e5hE=
+golang.org/x/net v0.28.0/go.mod h1:yqtgsTWOOnlGLG9GFRrK3++bGOUEkNBoHZc8MEDWPNg=
 golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.24.0 h1:Twjiwq9dn6R1fQcyiK+wQyHWfaz/BJB+YIpzU/Cv3Xg=

lib/util/time/sntp/continents.txt

@@ -0,0 +1,249 @@
+AD,EU
+AE,AS
+AF,AS
+AG,NA
+AI,NA
+AL,EU
+AM,AS
+AO,AF
+AQ,AN
+AR,SA
+AS,OC
+AT,EU
+AU,OC
+AW,NA
+AX,EU
+AZ,AS
+BA,EU
+BB,NA
+BD,AS
+BE,EU
+BF,AF
+BG,EU
+BH,AS
+BI,AF
+BJ,AF
+BL,NA
+BM,NA
+BN,AS
+BO,SA
+BQ,NA
+BR,SA
+BS,NA
+BT,AS
+BV,AN
+BW,AF
+BY,EU
+BZ,NA
+CA,NA
+CC,AS
+CD,AF
+CF,AF
+CG,AF
+CH,EU
+CI,AF
+CK,OC
+CL,SA
+CM,AF
+CN,AS
+CO,SA
+CR,NA
+CU,NA
+CV,AF
+CW,NA
+CX,AS
+CY,AS
+CZ,EU
+DE,EU
+DJ,AF
+DK,EU
+DM,NA
+DO,NA
+DZ,AF
+EC,SA
+EE,EU
+EG,AF
+EH,AF
+ER,AF
+ES,EU
+ET,AF
+FI,EU
+FJ,OC
+FK,SA
+FM,OC
+FO,EU
+FR,EU
+GA,AF
+GB,EU
+GD,NA
+GE,AS
+GF,SA
+GG,EU
+GH,AF
+GI,EU
+GL,NA
+GM,AF
+GN,AF
+GP,NA
+GQ,AF
+GR,EU
+GS,AN
+GT,NA
+GU,OC
+GW,AF
+GY,SA
+HK,AS
+HM,AN
+HN,NA
+HR,EU
+HT,NA
+HU,EU
+ID,AS
+IE,EU
+IL,AS
+IM,EU
+IN,AS
+IO,AS
+IQ,AS
+IR,AS
+IS,EU
+IT,EU
+JE,EU
+JM,NA
+JO,AS
+JP,AS
+KE,AF
+KG,AS
+KH,AS
+KI,OC
+KM,AF
+KN,NA
+KP,AS
+KR,AS
+KW,AS
+KY,NA
+KZ,AS
+LA,AS
+LB,AS
+LC,NA
+LI,EU
+LK,AS
+LR,AF
+LS,AF
+LT,EU
+LU,EU
+LV,EU
+LY,AF
+MA,AF
+MC,EU
+MD,EU
+ME,EU
+MF,NA
+MG,AF
+MH,OC
+MK,EU
+ML,AF
+MM,AS
+MN,AS
+MO,AS
+MP,OC
+MQ,NA
+MR,AF
+MS,NA
+MT,EU
+MU,AF
+MV,AS
+MW,AF
+MX,NA
+MY,AS
+MZ,AF
+NA,AF
+NC,OC
+NE,AF
+NF,OC
+NG,AF
+NI,NA
+NL,EU
+NO,EU
+NP,AS
+NR,OC
+NU,OC
+NZ,OC
+OM,AS
+PA,NA
+PE,SA
+PF,OC
+PG,OC
+PH,AS
+PK,AS
+PL,EU
+PM,NA
+PN,OC
+PR,NA
+PS,AS
+PT,EU
+PW,OC
+PY,SA
+QA,AS
+RE,AF
+RO,EU
+RS,EU
+RU,EU
+RW,AF
+SA,AS
+SB,OC
+SC,AF
+SD,AF
+SE,EU
+SG,AS
+SH,AF
+SI,EU
+SJ,EU
+SK,EU
+SL,AF
+SM,EU
+SN,AF
+SO,AF
+SR,SA
+SS,AF
+ST,AF
+SV,NA
+SX,NA
+SY,AS
+SZ,AF
+TC,NA
+TD,AF
+TF,AN
+TG,AF
+TH,AS
+TJ,AS
+TK,OC
+TL,AS
+TM,AS
+TN,AF
+TO,OC
+TR,AS
+TT,NA
+TV,OC
+TW,AS
+TZ,AF
+UA,EU
+UG,AF
+UM,OC
+US,NA
+UY,SA
+UZ,AS
+VA,EU
+VC,NA
+VE,SA
+VG,NA
+VI,NA
+VN,AS
+VU,OC
+WF,OC
+WS,OC
+YE,AS
+YT,AF
+ZA,AF
+ZM,AF
+ZW,AF

lib/util/time/sntp/doc.md

@@ -0,0 +1,128 @@
+# sntp
+--
+    import "github.com/go-i2p/go-i2p/lib/util/sntp"
+
+## Usage
+
+```go
+import "github.com/go-i2p/go-i2p/lib/util/sntp"
+```
+
+## Types
+
+### type RouterTimestamper
+
+```go
+type RouterTimestamper struct {
+    servers           []string
+    priorityServers   [][]string
+    listeners         []UpdateListener
+    queryFrequency    time.Duration
+    concurringServers int
+    consecutiveFails  int
+    disabled          bool
+    initialized       bool
+    wellSynced        bool
+    isRunning         bool
+    mutex             sync.Mutex
+    zones             *Zones
+    stopChan          chan struct{}
+    waitGroup         sync.WaitGroup
+    ntpClient         NTPClient
+}
+```
+
+RouterTimestamper is responsible for querying NTP servers and managing time synchronization.
+
+#### func NewRouterTimestamper
+
+```go
+func NewRouterTimestamper(client NTPClient) *RouterTimestamper
+```
+
+NewRouterTimestamper creates a new RouterTimestamper instance.
+
+#### func (*RouterTimestamper) Start
+
+```go
+func (rt *RouterTimestamper) Start()
+```
+
+Start begins the time synchronization process.
+
+#### func (*RouterTimestamper) Stop
+
+```go
+func (rt *RouterTimestamper) Stop()
+```
+
+Stop halts the time synchronization process.
+
+#### func (*RouterTimestamper) AddListener
+
+```go
+func (rt *RouterTimestamper) AddListener(listener UpdateListener)
+```
+
+AddListener adds a new listener for time updates.
+
+#### func (*RouterTimestamper) RemoveListener
+
+```go
+func (rt *RouterTimestamper) RemoveListener(listener UpdateListener)
+```
+
+RemoveListener removes a listener from receiving time updates.
+
+#### func (*RouterTimestamper) WaitForInitialization
+
+```go
+func (rt *RouterTimestamper) WaitForInitialization()
+```
+
+WaitForInitialization blocks until the RouterTimestamper is initialized or a timeout occurs.
+
+#### func (*RouterTimestamper) TimestampNow
+
+```go
+func (rt *RouterTimestamper) TimestampNow()
+```
+
+TimestampNow triggers an immediate time synchronization.
+
+### type UpdateListener
+
+```go
+type UpdateListener interface {
+    SetNow(now time.Time, stratum uint8)
+}
+```
+
+UpdateListener is an interface that listeners must implement to receive time updates.
+
+### type Zones
+
+```go
+type Zones struct {
+    countryToZone   map[string]string
+    continentToZone map[string]string
+}
+```
+
+Zones manages mappings between country codes, continent codes, and NTP zones.
+
+#### func NewZones
+
+```go
+func NewZones() *Zones
+```
+
+NewZones creates a new Zones instance and initializes it with data.
+
+#### func (*Zones) GetZone
+
+```go
+func (z *Zones) GetZone(countryCode string) string
+```
+
+GetZone returns the NTP zone for a given country code.

lib/util/time/sntp/router_timestamper.go

@@ -0,0 +1,322 @@
+package sntp
+
+import (
+	"fmt"
+	"math/rand"
+	"net"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/beevik/ntp"
+)
+
+type NTPClient interface {
+	QueryWithOptions(host string, options ntp.QueryOptions) (*ntp.Response, error)
+}
+
+type DefaultNTPClient struct{}
+
+func (c *DefaultNTPClient) QueryWithOptions(host string, options ntp.QueryOptions) (*ntp.Response, error) {
+	return ntp.QueryWithOptions(host, options)
+}
+
+type RouterTimestamper struct {
+	servers           []string
+	priorityServers   [][]string
+	listeners         []UpdateListener
+	queryFrequency    time.Duration
+	concurringServers int
+	consecutiveFails  int
+	disabled          bool
+	initialized       bool
+	wellSynced        bool
+	isRunning         bool
+	mutex             sync.Mutex
+	zones             *Zones
+	stopChan          chan struct{}
+	waitGroup         sync.WaitGroup
+	ntpClient         NTPClient
+}
+
+const (
+	minQueryFrequency     = 5 * time.Minute
+	defaultQueryFrequency = 11 * time.Minute
+	defaultServerList     = "0.pool.ntp.org,1.pool.ntp.org,2.pool.ntp.org"
+	defaultDisabled       = false
+	defaultConcurring     = 3
+	maxConsecutiveFails   = 10
+	defaultTimeout        = 10 * time.Second
+	shortTimeout          = 5 * time.Second
+	maxWaitInitialization = 45 * time.Second
+	maxVariance           = 10 * time.Second
+)
+
+func NewRouterTimestamper(client NTPClient) *RouterTimestamper {
+	rt := &RouterTimestamper{
+		listeners:         []UpdateListener{},
+		disabled:          defaultDisabled,
+		queryFrequency:    defaultQueryFrequency,
+		concurringServers: defaultConcurring,
+		zones:             NewZones(),
+		stopChan:          make(chan struct{}),
+		ntpClient:         client,
+	}
+	rt.updateConfig()
+	return rt
+}
+
+func (rt *RouterTimestamper) Start() {
+	if rt.disabled || rt.initialized {
+		return
+	}
+	rt.isRunning = true
+	rt.waitGroup.Add(1)
+	go rt.run()
+}
+
+func (rt *RouterTimestamper) Stop() {
+	if rt.isRunning {
+		rt.isRunning = false
+		close(rt.stopChan)
+		rt.waitGroup.Wait()
+	}
+}
+
+func (rt *RouterTimestamper) AddListener(listener UpdateListener) {
+	rt.mutex.Lock()
+	defer rt.mutex.Unlock()
+	rt.listeners = append(rt.listeners, listener)
+}
+
+func (rt *RouterTimestamper) RemoveListener(listener UpdateListener) {
+	rt.mutex.Lock()
+	defer rt.mutex.Unlock()
+	for i, l := range rt.listeners {
+		if l == listener {
+			rt.listeners = append(rt.listeners[:i], rt.listeners[i+1:]...)
+			break
+		}
+	}
+}
+
+func (rt *RouterTimestamper) WaitForInitialization() {
+	start := time.Now()
+	for {
+		rt.mutex.Lock()
+		initialized := rt.initialized
+		rt.mutex.Unlock()
+		if initialized {
+			return
+		}
+		if time.Since(start) > maxWaitInitialization {
+			return
+		}
+		time.Sleep(100 * time.Millisecond)
+	}
+}
+
+func (rt *RouterTimestamper) TimestampNow() {
+	if rt.initialized && rt.isRunning && !rt.disabled {
+		go rt.runOnce()
+	}
+}
+
+func (rt *RouterTimestamper) run() {
+	defer rt.waitGroup.Done()
+	lastFailed := false
+	for rt.isRunning {
+		rt.updateConfig()
+		preferIPv6 := checkIPv6Connectivity()
+		if !rt.disabled {
+			if rt.priorityServers != nil {
+				for _, servers := range rt.priorityServers {
+					lastFailed = !rt.queryTime(servers, shortTimeout, preferIPv6)
+					if !lastFailed {
+						break
+					}
+				}
+			}
+			if rt.priorityServers == nil || lastFailed {
+				prefIPv6 := preferIPv6 && !lastFailed && rand.Intn(4) != 0
+				lastFailed = !rt.queryTime(rt.servers, defaultTimeout, prefIPv6)
+			}
+		}
+
+		rt.mutex.Lock()
+		if !rt.initialized {
+			rt.initialized = true
+		}
+		rt.mutex.Unlock()
+
+		var sleepTime time.Duration
+		if lastFailed {
+			rt.consecutiveFails++
+			if rt.consecutiveFails >= maxConsecutiveFails {
+				sleepTime = 30 * time.Minute
+			} else {
+				sleepTime = 30 * time.Second
+			}
+		} else {
+			rt.consecutiveFails = 0
+			randomDelay := time.Duration(rand.Int63n(int64(rt.queryFrequency / 2)))
+			sleepTime = rt.queryFrequency + randomDelay
+			if rt.wellSynced {
+				sleepTime *= 3
+			}
+		}
+
+		select {
+		case <-time.After(sleepTime):
+		case <-rt.stopChan:
+			return
+		}
+	}
+}
+
+func (rt *RouterTimestamper) runOnce() {
+	lastFailed := false
+	rt.updateConfig()
+	preferIPv6 := checkIPv6Connectivity()
+	if !rt.disabled {
+		if rt.priorityServers != nil {
+			for _, servers := range rt.priorityServers {
+				lastFailed = !rt.queryTime(servers, shortTimeout, preferIPv6)
+				if !lastFailed {
+					break
+				}
+			}
+		}
+		if rt.priorityServers == nil || lastFailed {
+			prefIPv6 := preferIPv6 && !lastFailed && rand.Intn(4) != 0
+			lastFailed = !rt.queryTime(rt.servers, defaultTimeout, prefIPv6)
+		}
+	}
+
+	rt.mutex.Lock()
+	if !rt.initialized {
+		rt.initialized = true
+	}
+	rt.mutex.Unlock()
+}
+
+func (rt *RouterTimestamper) queryTime(servers []string, timeout time.Duration, preferIPv6 bool) bool {
+	found := make([]time.Duration, rt.concurringServers)
+	var expectedDelta time.Duration
+	rt.wellSynced = false
+
+	for i := 0; i < rt.concurringServers; i++ {
+		server := servers[rand.Intn(len(servers))]
+		options := ntp.QueryOptions{
+			Timeout: timeout,
+			//TTL:     5,
+		}
+
+		if preferIPv6 {
+			server = fmt.Sprintf("[%s]:123", server)
+		}
+
+		response, err := rt.ntpClient.QueryWithOptions(server, options)
+		if err != nil {
+			fmt.Printf("NTP query failed: %v\n", err)
+			return false
+		}
+
+		now := time.Now().Add(response.ClockOffset)
+		delta := now.Sub(time.Now())
+		found[i] = delta
+
+		if i == 0 {
+			if absDuration(delta) < maxVariance {
+				if absDuration(delta) < 500*time.Millisecond {
+					rt.wellSynced = true
+				}
+				break
+			} else {
+				expectedDelta = delta
+			}
+		} else {
+			if absDuration(delta-expectedDelta) > maxVariance {
+				// Variance too high, fail this attempt
+				return false
+			}
+		}
+	}
+
+	rt.stampTime(time.Now().Add(found[0]))
+	return true
+}
+
+func (rt *RouterTimestamper) stampTime(now time.Time) {
+	rt.mutex.Lock()
+	defer rt.mutex.Unlock()
+	for _, listener := range rt.listeners {
+		listener.SetNow(now, 0)
+	}
+}
+
+func (rt *RouterTimestamper) updateConfig() {
+	serverList := defaultServerList
+	rt.servers = strings.Split(serverList, ",")
+	for i, server := range rt.servers {
+		rt.servers[i] = strings.TrimSpace(server)
+	}
+
+	if rt.queryFrequency < minQueryFrequency {
+		rt.queryFrequency = minQueryFrequency
+	}
+
+	if rt.concurringServers < 1 {
+		rt.concurringServers = 1
+	} else if rt.concurringServers > 4 {
+		rt.concurringServers = 4
+	}
+
+	country := getLocalCountryCode()
+	if country != "" && country != "a1" && country != "a2" {
+		rt.priorityServers = [][]string{}
+		p1 := []string{
+			fmt.Sprintf("0.%s.pool.ntp.org", country),
+			fmt.Sprintf("1.%s.pool.ntp.org", country),
+			fmt.Sprintf("2.%s.pool.ntp.org", country),
+		}
+		rt.priorityServers = append(rt.priorityServers, p1)
+		zone := rt.zones.GetZone(country)
+		if zone != "" {
+			p2 := []string{
+				fmt.Sprintf("0.%s.pool.ntp.org", zone),
+				fmt.Sprintf("1.%s.pool.ntp.org", zone),
+				fmt.Sprintf("2.%s.pool.ntp.org", zone),
+			}
+			rt.priorityServers = append(rt.priorityServers, p2)
+		}
+	} else {
+		rt.priorityServers = nil
+	}
+}
+
+func checkIPv6Connectivity() bool {
+	addrs, err := net.InterfaceAddrs()
+	if err != nil {
+		return false
+	}
+	for _, addr := range addrs {
+		if ipNet, ok := addr.(*net.IPNet); ok && !ipNet.IP.IsLoopback() {
+			if ipNet.IP.To16() != nil && ipNet.IP.To4() == nil {
+				return true
+			}
+		}
+	}
+	return false
+}
+
+func absDuration(d time.Duration) time.Duration {
+	if d < 0 {
+		return -d
+	}
+	return d
+}
+
+func getLocalCountryCode() string {
+	return ""
+}

lib/util/time/sntp/router_timestamper_test.go

@@ -0,0 +1,202 @@
+package sntp
+
+import (
+	"github.com/beevik/ntp"
+	"sync"
+	"testing"
+	"time"
+)
+
+type MockNTPClient struct {
+	ClockOffset time.Duration
+	Error       error
+}
+
+func (c *MockNTPClient) QueryWithOptions(host string, options ntp.QueryOptions) (*ntp.Response, error) {
+	if c.Error != nil {
+		return nil, c.Error
+	}
+	return &ntp.Response{
+		ClockOffset: c.ClockOffset,
+	}, nil
+}
+
+type MockListener struct {
+	mu       sync.Mutex
+	updates  []time.Time
+	stratums []uint8
+}
+
+func (ml *MockListener) SetNow(now time.Time, stratum uint8) {
+	ml.mu.Lock()
+	defer ml.mu.Unlock()
+	ml.updates = append(ml.updates, now)
+	ml.stratums = append(ml.stratums, stratum)
+}
+
+func TestRouterTimestamperInitialization(t *testing.T) {
+	defaultClient := &DefaultNTPClient{}
+	timestamper := NewRouterTimestamper(defaultClient)
+	if timestamper == nil {
+		t.Fatal("Expected RouterTimestamper instance, got nil")
+	}
+}
+
+func TestAddAndRemoveListener(t *testing.T) {
+	defaultClient := &DefaultNTPClient{}
+	timestamper := NewRouterTimestamper(defaultClient)
+	listener := &MockListener{}
+
+	timestamper.AddListener(listener)
+	if len(timestamper.listeners) != 1 {
+		t.Errorf("Expected 1 listener, got %d", len(timestamper.listeners))
+	}
+
+	timestamper.RemoveListener(listener)
+	if len(timestamper.listeners) != 0 {
+		t.Errorf("Expected 0 listeners, got %d", len(timestamper.listeners))
+	}
+}
+
+func TestTimestampNow(t *testing.T) {
+	defaultClient := &DefaultNTPClient{}
+	timestamper := NewRouterTimestamper(defaultClient)
+	listener := &MockListener{}
+	timestamper.AddListener(listener)
+
+	// Mock Injection
+	mockNTPClient := &MockNTPClient{
+		ClockOffset: 1 * time.Second,
+	}
+	timestamper.ntpClient = mockNTPClient
+
+	timestamper.Start()
+	defer timestamper.Stop()
+
+	timestamper.WaitForInitialization()
+
+	// Trigger update
+	timestamper.TimestampNow()
+
+	time.Sleep(100 * time.Millisecond)
+
+	listener.mu.Lock()
+	defer listener.mu.Unlock()
+	if len(listener.updates) == 0 {
+		t.Error("Expected at least one time update, got none")
+	}
+}
+func TestTimestampNowWithRealNTP(t *testing.T) {
+	defaultClient := &DefaultNTPClient{}
+	timestamper := NewRouterTimestamper(defaultClient)
+	listener := &MockListener{}
+	timestamper.AddListener(listener)
+
+	timestamper.Start()
+	defer timestamper.Stop()
+
+	t.Log("Waiting for initialization...")
+	timestamper.WaitForInitialization()
+	t.Log("Initialization complete")
+
+	// Trigger an immediate time update
+	t.Log("Triggering time update...")
+	timestamper.TimestampNow()
+
+	timeout := time.After(30 * time.Second)
+	updateReceived := make(chan struct{})
+
+	go func() {
+		for {
+			listener.mu.Lock()
+			if len(listener.updates) > 0 {
+				listener.mu.Unlock()
+				updateReceived <- struct{}{}
+				return
+			}
+			listener.mu.Unlock()
+			time.Sleep(100 * time.Millisecond)
+		}
+	}()
+
+	select {
+	case <-updateReceived:
+		t.Log("Update received successfully")
+	case <-timeout:
+		t.Error("Timed out waiting for NTP update")
+	}
+
+	listener.mu.Lock()
+	defer listener.mu.Unlock()
+	if len(listener.updates) == 0 {
+		t.Error("Expected at least one time update, got none")
+	} else {
+		t.Logf("Received %d updates", len(listener.updates))
+		for i, update := range listener.updates {
+			t.Logf("Update %d: %v", i, update)
+		}
+	}
+
+	t.Logf("NTP Servers: %v", timestamper.servers)
+	t.Logf("Priority Servers: %v", timestamper.priorityServers)
+}
+func TestWaitForInitialization(t *testing.T) {
+	defaultClient := &DefaultNTPClient{}
+	timestamper := NewRouterTimestamper(defaultClient)
+	start := time.Now()
+	go func() {
+		time.Sleep(1 * time.Second)
+		timestamper.mutex.Lock()
+		timestamper.initialized = true
+		timestamper.mutex.Unlock()
+	}()
+	timestamper.WaitForInitialization()
+	elapsed := time.Since(start)
+	if elapsed < 1*time.Second {
+		t.Errorf("Expected to wait at least 1 second, waited %v", elapsed)
+	}
+}
+
+func TestQueryTime(t *testing.T) {
+	defaultClient := &DefaultNTPClient{}
+	timestamper := NewRouterTimestamper(defaultClient)
+	listener := &MockListener{}
+	timestamper.AddListener(listener)
+
+	// Mock injection
+	mockNTPClient := &MockNTPClient{
+		ClockOffset: 1 * time.Second,
+	}
+	timestamper.ntpClient = mockNTPClient
+
+	servers := []string{"pool.ntp.org"}
+	success := timestamper.queryTime(servers, 5*time.Second, false)
+	if !success {
+		t.Error("Expected queryTime to succeed")
+	}
+
+	// Ensure that the listener received an update
+	listener.mu.Lock()
+	defer listener.mu.Unlock()
+	if len(listener.updates) == 0 {
+		t.Error("Expected listener to receive time update")
+	}
+}
+
+func TestUpdateConfig(t *testing.T) {
+	defaultClient := &DefaultNTPClient{}
+	timestamper := NewRouterTimestamper(defaultClient)
+
+	// Modify the default configuration
+	timestamper.queryFrequency = 1 * time.Minute
+	timestamper.concurringServers = 5
+
+	timestamper.updateConfig()
+
+	if timestamper.queryFrequency < minQueryFrequency {
+		t.Errorf("Expected queryFrequency >= %v, got %v", minQueryFrequency, timestamper.queryFrequency)
+	}
+	if timestamper.concurringServers > 4 {
+		t.Errorf("Expected concurringServers <= 4, got %d", timestamper.concurringServers)
+	}
+}

lib/util/time/sntp/update_listener.go

@@ -0,0 +1,8 @@
+package sntp
+
+import "time"
+
+// UpdateListener is an interface that listeners must implement to receive time updates.
+type UpdateListener interface {
+	SetNow(now time.Time, stratum uint8)
+}

lib/util/time/sntp/zones.go

@@ -0,0 +1,90 @@
+package sntp
+
+import (
+	"bufio"
+	"embed"
+	"io"
+	"log"
+	"strings"
+)
+
+//go:embed continents.txt
+var continentsFS embed.FS
+
+type Zones struct {
+	countryToZone   map[string]string
+	continentToZone map[string]string
+}
+
+func NewZones() *Zones {
+	z := &Zones{
+		countryToZone:   make(map[string]string),
+		continentToZone: make(map[string]string),
+	}
+	z.initialize()
+	return z
+}
+
+func (z *Zones) GetZone(countryCode string) string {
+	countryCode = strings.ToLower(countryCode)
+	if zone, ok := z.countryToZone[countryCode]; ok {
+		return zone
+	}
+	return ""
+}
+
+func (z *Zones) initialize() {
+	zones := []string{
+		"AF", "africa",
+		"AN", "antarctica", // Who is living here?
+		"AS", "asia",
+		"EU", "europe",
+		"NA", "north-america",
+		"OC", "oceania",
+		"SA", "south-america",
+	}
+
+	for i := 0; i < len(zones); i += 2 {
+		z.continentToZone[zones[i]] = zones[i+1]
+	}
+
+	z.readContinentFile()
+}
+
+func (z *Zones) readContinentFile() {
+	file, err := continentsFS.Open("continents.txt")
+	if err != nil {
+		log.Printf("Error opening continents.txt: %v\n", err)
+		return
+	}
+	defer file.Close()
+
+	reader := bufio.NewReader(file)
+	for {
+		line, err := reader.ReadString('\n')
+		if err != nil && err != io.EOF {
+			log.Printf("Error reading continents.txt: %v\n", err)
+			break
+		}
+		if err == io.EOF && line == "" {
+			break
+		}
+
+		line = strings.TrimSpace(line)
+		if len(line) == 0 || strings.HasPrefix(line, "#") {
+			continue
+		}
+
+		parts := strings.Split(line, ",")
+		if len(parts) < 2 {
+			continue
+		}
+
+		countryCode := strings.ToLower(strings.TrimSpace(parts[0]))
+		continentCode := strings.ToUpper(strings.TrimSpace(parts[1]))
+
+		if zone, ok := z.continentToZone[continentCode]; ok {
+			z.countryToZone[countryCode] = zone
+		}
+	}
+}