wip: migrate to mono-repo. SPN has already been moved to spn/

service/netenv/network-change.go

@@ -0,0 +1,104 @@
+package netenv
+
+import (
+	"bytes"
+	"context"
+	"crypto/sha1"
+	"io"
+	"time"
+
+	"github.com/safing/portbase/log"
+	"github.com/safing/portbase/utils"
+)
+
+var (
+	networkChangeCheckTrigger   = make(chan struct{}, 1)
+	networkChangedBroadcastFlag = utils.NewBroadcastFlag()
+)
+
+// GetNetworkChangedFlag returns a flag to be notified about a network change.
+func GetNetworkChangedFlag() *utils.Flag {
+	return networkChangedBroadcastFlag.NewFlag()
+}
+
+func notifyOfNetworkChange() {
+	networkChangedBroadcastFlag.NotifyAndReset()
+	module.TriggerEvent(NetworkChangedEvent, nil)
+}
+
+// TriggerNetworkChangeCheck triggers a network change check.
+func TriggerNetworkChangeCheck() {
+	select {
+	case networkChangeCheckTrigger <- struct{}{}:
+	default:
+	}
+}
+
+func monitorNetworkChanges(ctx context.Context) error {
+	var lastNetworkChecksum []byte
+
+serviceLoop:
+	for {
+		trigger := false
+
+		var ticker *time.Ticker
+		if Online() {
+			ticker = monitorNetworkChangeOnlineTicker
+		} else {
+			ticker = monitorNetworkChangeOfflineTicker
+		}
+
+		// wait for trigger
+		select {
+		case <-ctx.Done():
+			return nil
+		case <-networkChangeCheckTrigger:
+			// don't fall through because the online change check
+			// triggers the networkChangeCheck this way. If we would set
+			// trigger == true we would trigger the online check again
+			// resulting in a loop of pointless checks.
+		case <-ticker.C:
+			trigger = true
+		}
+
+		// check network for changes
+		// create hashsum of current network config
+		hasher := sha1.New() //nolint:gosec // not used for security
+		interfaces, err := osGetNetworkInterfaces()
+		if err != nil {
+			log.Warningf("netenv: failed to get interfaces: %s", err)
+			continue
+		}
+		for _, iface := range interfaces {
+			_, _ = io.WriteString(hasher, iface.Name)
+			// log.Tracef("adding: %s", iface.Name)
+			_, _ = io.WriteString(hasher, iface.Flags.String())
+			// log.Tracef("adding: %s", iface.Flags.String())
+			addrs, err := iface.Addrs()
+			if err != nil {
+				log.Warningf("netenv: failed to get addrs from interface %s: %s", iface.Name, err)
+				continue
+			}
+			for _, addr := range addrs {
+				_, _ = io.WriteString(hasher, addr.String())
+				// log.Tracef("adding: %s", addr.String())
+			}
+		}
+		newChecksum := hasher.Sum(nil)
+
+		// compare checksum with last
+		if !bytes.Equal(lastNetworkChecksum, newChecksum) {
+			if len(lastNetworkChecksum) == 0 {
+				lastNetworkChecksum = newChecksum
+				continue serviceLoop
+			}
+			lastNetworkChecksum = newChecksum
+
+			if trigger {
+				TriggerOnlineStatusInvestigation()
+			}
+			notifyOfNetworkChange()
+		}
+
+	}
+}