feat: refactor interception modules into pausable group

- Add GroupModule to wrap interception, dnsmonitor, and compat modules
- Simplify pause/resume operations by grouping related modules
- Update worker info collection to handle nested module groups
- Remove deprecated flags and improve module lifecycle management
- Add proper atomic state tracking for nfqueue interception

https://github.com/safing/portmaster/issues/2050

service/compat/module.go

@@ -78,14 +78,20 @@ func prep() error {
 }
 
 func start() error {
-	isActive.Store(true)
+	// Create fresh worker managers on Start() to enable clean restarts after Stop().
+	// (after module.Manager().Stop() has been called, all workers are stopped and cannot be reused)
+	module.selfcheckWorkerMgr = module.Manager().NewWorkerMgr("compatibility self-check", selfcheckTaskFunc, nil)
+	module.cleanNotifyThresholdWorkerMgr = module.Manager().NewWorkerMgr("clean notify thresholds", cleanNotifyThreshold, nil)
 
 	startNotify()
 
 	selfcheckNetworkChangedFlag.Refresh()
+
+	// Schedule periodic self-checks.
 	module.selfcheckWorkerMgr.Repeat(5 * time.Minute).Delay(selfcheckTaskRetryAfter)
 	module.cleanNotifyThresholdWorkerMgr.Repeat(1 * time.Hour)
 
+	// Add network change callback to trigger immediate self-check.
 	module.instance.NetEnv().EventNetworkChange.AddCallback("trigger compat self-check", func(_ *mgr.WorkerCtx, _ struct{}) (bool, error) {
 		module.selfcheckWorkerMgr.Delay(selfcheckTaskRetryAfter)
 		return false, nil
@@ -94,16 +100,11 @@ func start() error {
 }
 
 func stop() error {
-	isActive.Store(false)
 	resetSelfCheckState()
-
 	return nil
 }
 
 func selfcheckTaskFunc(wc *mgr.WorkerCtx) error {
-	if !isActive.Load() {
-		return nil
-	}
 
 	// Create tracing logger.
 	ctx, tracer := log.AddTracer(wc.Ctx())
@@ -166,9 +167,6 @@ func SelfCheckIsFailing() bool {
 var (
 	module     *Compat
 	shimLoaded atomic.Bool
-	// isActive is a simple shutdown flag to prevent self-check worker from executing during stop().
-	// TODO: consider correct start/stop of the workers instead.
-	isActive atomic.Bool
 )
 
 // New returns a new Compat module.
@@ -180,11 +178,7 @@ func New(instance instance) (*Compat, error) {
 	module = &Compat{
 		mgr:      m,
 		instance: instance,
-
-		selfcheckWorkerMgr:            m.NewWorkerMgr("compatibility self-check", selfcheckTaskFunc, nil),
-		cleanNotifyThresholdWorkerMgr: m.NewWorkerMgr("clean notify thresholds", cleanNotifyThreshold, nil),
-
-		states: mgr.NewStateMgr(m),
+		states:   mgr.NewStateMgr(m),
 	}
 	if err := prep(); err != nil {
 		return nil, err

service/control/module.go

@@ -8,8 +8,6 @@ import (
 
 	"github.com/safing/portmaster/base/config"
 	"github.com/safing/portmaster/base/notifications"
-	"github.com/safing/portmaster/service/compat"
-	"github.com/safing/portmaster/service/firewall/interception"
 	"github.com/safing/portmaster/service/mgr"
 )
 
@@ -32,8 +30,7 @@ type Control struct {
 
 type instance interface {
 	Config() *config.Config
-	Interception() *interception.Interception
-	Compat() *compat.Compat
+	InterceptionGroup() *mgr.GroupModule
 	SPNGroup() *mgr.ExtendedGroup
 	IsShuttingDown() bool
 }

service/control/pause.go

@@ -68,16 +68,9 @@ func (c *Control) pause(duration time.Duration, onlySPN bool) (retErr error) {
 	}
 
 	if !c.pauseInfo.Interception {
-		modulesToResume := []mgr.Module{
-			c.instance.Compat(),
-			c.instance.Interception(),
+		if err := c.instance.InterceptionGroup().Stop(); err != nil {
+			return err
 		}
-		for _, m := range modulesToResume {
-			if err := m.Stop(); err != nil {
-				return err
-			}
-		}
-
 		c.mgr.Info("interception paused")
 		c.pauseInfo.Interception = true
 	}
@@ -106,14 +99,8 @@ func (c *Control) resume() (retErr error) {
 	c.stopResumeWorker()
 
 	if c.pauseInfo.Interception {
-		modulesToResume := []mgr.Module{
-			c.instance.Interception(),
-			c.instance.Compat(),
-		}
-		for _, m := range modulesToResume {
-			if err := m.Start(); err != nil {
-				return err
-			}
+		if err := c.instance.InterceptionGroup().Start(); err != nil {
+			return err
 		}
 		c.mgr.Info("interception resumed")
 		c.pauseInfo.Interception = false

service/debug.go

@@ -24,10 +24,26 @@ func (i *Instance) GetWorkerInfo() (*mgr.WorkerInfo, error) {
 	for _, m := range i.serviceGroup.Modules() {
 		wi, _ := m.Manager().WorkerInfo(snapshot) // Does not fail when we provide a snapshot.
 		infos = append(infos, wi)
+
+		// Check if module is a nested modules group
+		if gm, ok := m.(*mgr.GroupModule); ok {
+			for _, sm := range gm.Modules() {
+				wi, _ := sm.Manager().WorkerInfo(snapshot) // Does not fail when we provide a snapshot.
+				infos = append(infos, wi)
+			}
+		}
 	}
 	for _, m := range i.SpnGroup.Modules() {
 		wi, _ := m.Manager().WorkerInfo(snapshot) // Does not fail when we provide a snapshot.
 		infos = append(infos, wi)
+
+		// Check if module is a nested modules group
+		if gm, ok := m.(*mgr.GroupModule); ok {
+			for _, sm := range gm.Modules() {
+				wi, _ := sm.Manager().WorkerInfo(snapshot) // Does not fail when we provide a snapshot.
+				infos = append(infos, wi)
+			}
+		}
 	}
 
 	return mgr.MergeWorkerInfo(infos...), nil

service/firewall/interception/interception_linux.go

@@ -34,11 +34,6 @@ func startInterception(packets chan packet.Packet) error {
 
 // stop starts the interception.
 func stopInterception() error {
-	// TODO: stop ebpf workers gracefully
-	// E.g.:
-	// 		module.mgr.Cancel()
-	// 		<-m.Done()
-
 	return StopNfqueueInterception()
 }
 

service/firewall/interception/nfqueue_linux.go

@@ -1,10 +1,10 @@
 package interception
 
 import (
-	"flag"
 	"fmt"
 	"sort"
 	"strings"
+	"sync/atomic"
 
 	"github.com/coreos/go-iptables/iptables"
 	"github.com/hashicorp/go-multierror"
@@ -30,15 +30,10 @@ var (
 	out6Queue nfQueue
 	in6Queue  nfQueue
 
+	isRunning      atomic.Bool
 	shutdownSignal = make(chan struct{})
-
-	experimentalNfqueueBackend bool
 )
 
-func init() {
-	flag.BoolVar(&experimentalNfqueueBackend, "experimental-nfqueue", false, "(deprecated flag; always used)")
-}
-
 // nfQueue encapsulates nfQueue providers.
 type nfQueue interface {
 	PacketChannel() <-chan packet.Packet
@@ -262,12 +257,13 @@ func deactivateIPTables(protocol iptables.Protocol, rules, chains []string) erro
 
 // StartNfqueueInterception starts the nfqueue interception.
 func StartNfqueueInterception(packets chan<- packet.Packet) (err error) {
-	// @deprecated, remove in v1
-	if experimentalNfqueueBackend {
-		log.Warningf("[DEPRECATED] --experimental-nfqueue has been deprecated as the backend is now used by default")
-		log.Warningf("[DEPRECATED] please remove the flag from your configuration!")
+	if !isRunning.CompareAndSwap(false, true) {
+		return nil // already running
 	}
 
+	// Reset shutdown signal
+	shutdownSignal = make(chan struct{})
+
 	err = activateNfqueueFirewall()
 	if err != nil {
 		return fmt.Errorf("could not initialize nfqueue: %w", err)
@@ -305,6 +301,11 @@ func StartNfqueueInterception(packets chan<- packet.Packet) (err error) {
 
 // StopNfqueueInterception stops the nfqueue interception.
 func StopNfqueueInterception() error {
+	if !isRunning.CompareAndSwap(true, false) {
+		return nil // not running
+	}
+
+	// Signal shutdown to packet handler
 	defer close(shutdownSignal)
 
 	if out4Queue != nil {

service/instance.go

@@ -58,7 +58,8 @@ type Instance struct {
 	shutdownCtx       context.Context
 	cancelShutdownCtx context.CancelFunc
 
-	serviceGroup *mgr.Group
+	serviceGroup             *mgr.Group
+	serviceGroupInterception *mgr.GroupModule
 
 	binDir  string
 	dataDir string
@@ -313,6 +314,12 @@ func New(svcCfg *ServiceConfig) (*Instance, error) { //nolint:maintidx
 		return instance, fmt.Errorf("create terminal module: %w", err)
 	}
 
+	// Grouped interception modules that can be paused/resumed together.
+	instance.serviceGroupInterception = mgr.NewGroupModule("Interception Group",
+		instance.interception,
+		instance.dnsmonitor,
+		instance.compat)
+
 	// Add all modules to instance group.
 	instance.serviceGroup = mgr.NewGroup(
 		instance.base,
@@ -340,10 +347,13 @@ func New(svcCfg *ServiceConfig) (*Instance, error) { //nolint:maintidx
 		instance.resolver,
 		instance.filterLists,
 		instance.customlist,
-		instance.interception,
-		instance.dnsmonitor,
 
-		instance.compat,
+		// Grouped interception modules:
+		// 		instance.interception,
+		// 		instance.dnsmonitor,
+		// 		instance.compat
+		instance.serviceGroupInterception,
+
 		instance.status,
 		instance.broadcasts,
 		instance.sync,
@@ -549,6 +559,11 @@ func (i *Instance) Interception() *interception.Interception {
 	return i.interception
 }
 
+// InterceptionGroup returns the grouped interception modules that can be paused together.
+func (i *Instance) InterceptionGroup() *mgr.GroupModule {
+	return i.serviceGroupInterception
+}
+
 // DNSMonitor returns the dns-listener module.
 func (i *Instance) DNSMonitor() *dnsmonitor.DNSMonitor {
 	return i.dnsmonitor

service/mgr/group_module.go

@@ -0,0 +1,33 @@
+package mgr
+
+// GroupModule is a module that wraps a group of modules,
+// to allow nesting groups of modules in parent group.
+type GroupModule struct {
+	mgr   *Manager
+	group *Group
+}
+
+func NewGroupModule(name string, modules ...Module) *GroupModule {
+	return &GroupModule{
+		mgr:   New(name),
+		group: NewGroup(modules...),
+	}
+}
+
+func (gm *GroupModule) Manager() *Manager {
+	return gm.mgr
+}
+
+func (gm *GroupModule) Start() error {
+	return gm.group.Start()
+}
+
+func (gm *GroupModule) Stop() error {
+	return gm.group.Stop()
+}
+
+// Modules returns the modules in the group wrapped by this group module.
+// (mimics Group.Modules())
+func (gm *GroupModule) Modules() []Module {
+	return gm.group.Modules()
+}