Add gw change polling and time drift detection (informational only)

client/internal/networkmonitor/check_change_darwin.go

@@ -7,6 +7,7 @@ import (
 	"errors"
 	"fmt"
 	"hash/fnv"
+	"net/netip"
 	"os/exec"
 	"syscall"
 	"time"
@@ -46,14 +47,22 @@ func checkChange(ctx context.Context, nexthopv4, nexthopv6 systemops.Nexthop) er
 		close(wakeUp)
 	}()
 
+	gatewayChanged := make(chan string)
+	go func() {
+		gatewayPoll(ctx, nexthopv4, nexthopv6, gatewayChanged)
+	}()
+
 	select {
 	case <-ctx.Done():
 		return ctx.Err()
 	case <-routeChanged:
-		log.Infof("route change detected")
+		log.Infof("route change detected via routing socket")
 		return nil
 	case <-wakeUp:
-		log.Infof("wakeup detected")
+		log.Infof("wakeup detected via sleep hash change")
+		return nil
+	case reason := <-gatewayChanged:
+		log.Infof("gateway change detected via polling: %s", reason)
 		return nil
 	}
 }
@@ -162,6 +171,9 @@ func wakeUpListen(ctx context.Context) {
 	ticker := time.NewTicker(5 * time.Second)
 	defer ticker.Stop()
 
+	lastCheck := time.Now()
+	const maxTickerDrift = 1 * time.Minute
+
 	for {
 		select {
 		case <-ctx.Done():
@@ -169,14 +181,42 @@ func wakeUpListen(ctx context.Context) {
 			return
 
 		case <-ticker.C:
+			now := time.Now()
+			elapsed := now.Sub(lastCheck)
+
+			// If more time passed than expected, system likely slept (informational only)
+			if elapsed > maxTickerDrift {
+				upOut, err := exec.Command("uptime").Output()
+				if err != nil {
+					log.Errorf("failed to run uptime command: %v", err)
+					upOut = []byte("unknown")
+				}
+				log.Infof("Time drift detected (potential wakeup): expected ~5s, actual %s, uptime: %s", elapsed, upOut)
+
+				currentV4, errV4 := systemops.GetNextHop(netip.IPv4Unspecified())
+				currentV6, errV6 := systemops.GetNextHop(netip.IPv6Unspecified())
+				if errV4 == nil {
+					log.Infof("Current IPv4 default gateway: %s via %s", currentV4.IP, currentV4.Intf.Name)
+				} else {
+					log.Debugf("No IPv4 default gateway: %v", errV4)
+				}
+				if errV6 == nil {
+					log.Infof("Current IPv6 default gateway: %s via %s", currentV6.IP, currentV6.Intf.Name)
+				} else {
+					log.Debugf("No IPv6 default gateway: %v", errV6)
+				}
+			}
+
 			newHash, err := readSleepTimeHash()
 			if err != nil {
 				log.Errorf("failed to read sleep time hash: %v", err)
+				lastCheck = now
 				continue
 			}
 
 			if newHash == initialHash {
-				log.Infof("no wakeup detected")
+				log.Debugf("no wakeup detected (hash unchanged: %d, time drift: %s)", initialHash, elapsed)
+				lastCheck = now
 				continue
 			}
 
@@ -185,7 +225,21 @@ func wakeUpListen(ctx context.Context) {
 				log.Errorf("failed to run uptime command: %v", err)
 				upOut = []byte("unknown")
 			}
-			log.Infof("Wakeup detected: %d -> %d, uptime: %s", initialHash, newHash, upOut)
+			log.Infof("Wakeup detected via hash change: %d -> %d, uptime: %s", initialHash, newHash, upOut)
+
+			currentV4, errV4 := systemops.GetNextHop(netip.IPv4Unspecified())
+			currentV6, errV6 := systemops.GetNextHop(netip.IPv6Unspecified())
+			if errV4 == nil {
+				log.Infof("Current IPv4 default gateway after wakeup: %s via %s", currentV4.IP, currentV4.Intf.Name)
+			} else {
+				log.Debugf("No IPv4 default gateway after wakeup: %v", errV4)
+			}
+			if errV6 == nil {
+				log.Infof("Current IPv6 default gateway after wakeup: %s via %s", currentV6.IP, currentV6.Intf.Name)
+			} else {
+				log.Debugf("No IPv6 default gateway after wakeup: %v", errV6)
+			}
+
 			return
 		}
 	}
@@ -207,9 +261,84 @@ func readSleepTimeHash() (uint32, error) {
 }
 
 func hash(data []byte) (uint32, error) {
-	hasher := fnv.New32a() // Create a new 32-bit FNV-1a hasher
+	hasher := fnv.New32a()
 	if _, err := hasher.Write(data); err != nil {
 		return 0, err
 	}
 	return hasher.Sum32(), nil
 }
+
+// gatewayPoll polls the default gateway every 5 seconds to detect changes that might be missed by routing socket or wake-up detection.
+func gatewayPoll(ctx context.Context, initialV4, initialV6 systemops.Nexthop, changed chan<- string) {
+	ticker := time.NewTicker(5 * time.Second)
+	defer ticker.Stop()
+
+	log.Infof("Gateway polling started - initial v4: %s via %v, v6: %s via %v",
+		initialV4.IP, initialV4.Intf, initialV6.IP, initialV6.Intf)
+
+	for {
+		select {
+		case <-ctx.Done():
+			log.Debug("context canceled, stopping gateway polling")
+			return
+
+		case <-ticker.C:
+			currentV4, errV4 := systemops.GetNextHop(netip.IPv4Unspecified())
+			currentV6, errV6 := systemops.GetNextHop(netip.IPv6Unspecified())
+
+			var reason string
+
+			if errV4 == nil && initialV4.IP.IsValid() {
+				if currentV4.IP.Compare(initialV4.IP) != 0 {
+					reason = fmt.Sprintf("IPv4 gateway changed from %s to %s", initialV4.IP, currentV4.IP)
+					log.Infof("Gateway poll detected change: %s", reason)
+					changed <- reason
+					return
+				}
+				if initialV4.Intf != nil && currentV4.Intf != nil && currentV4.Intf.Name != initialV4.Intf.Name {
+					reason = fmt.Sprintf("IPv4 interface changed from %s to %s", initialV4.Intf.Name, currentV4.Intf.Name)
+					log.Infof("Gateway poll detected change: %s", reason)
+					changed <- reason
+					return
+				}
+			} else if errV4 == nil && !initialV4.IP.IsValid() {
+				reason = "IPv4 gateway appeared"
+				log.Infof("Gateway poll detected change: %s (new: %s)", reason, currentV4.IP)
+				changed <- reason
+				return
+			} else if errV4 != nil && initialV4.IP.IsValid() {
+				reason = "IPv4 gateway disappeared"
+				log.Infof("Gateway poll detected change: %s", reason)
+				changed <- reason
+				return
+			}
+
+			if errV6 == nil && initialV6.IP.IsValid() {
+				if currentV6.IP.Compare(initialV6.IP) != 0 {
+					reason = fmt.Sprintf("IPv6 gateway changed from %s to %s", initialV6.IP, currentV6.IP)
+					log.Infof("Gateway poll detected change: %s", reason)
+					changed <- reason
+					return
+				}
+				if initialV6.Intf != nil && currentV6.Intf != nil && currentV6.Intf.Name != initialV6.Intf.Name {
+					reason = fmt.Sprintf("IPv6 interface changed from %s to %s", initialV6.Intf.Name, currentV6.Intf.Name)
+					log.Infof("Gateway poll detected change: %s", reason)
+					changed <- reason
+					return
+				}
+			} else if errV6 == nil && !initialV6.IP.IsValid() {
+				reason = "IPv6 gateway appeared"
+				log.Infof("Gateway poll detected change: %s (new: %s)", reason, currentV6.IP)
+				changed <- reason
+				return
+			} else if errV6 != nil && initialV6.IP.IsValid() {
+				reason = "IPv6 gateway disappeared"
+				log.Infof("Gateway poll detected change: %s", reason)
+				changed <- reason
+				return
+			}
+
+			log.Debugf("Gateway poll: no change detected")
+		}
+	}
+}