refactor: enhance AutoInterface with done channel and improved locking for concurrency

pkg/interfaces/auto.go

@@ -53,12 +53,13 @@ type AutoInterface struct {
 	timedOutInterfaces map[string]time.Time
 	allowedInterfaces  []string
 	ignoredInterfaces  []string
-	mutex              sync.RWMutex
 	outboundConn       *net.UDPConn
 	announceInterval   time.Duration
 	peerJobInterval    time.Duration
 	peeringTimeout     time.Duration
 	mcastEchoTimeout   time.Duration
+	done               chan struct{}
+	stopOnce           sync.Once
 }
 
 type AdoptedInterface struct {
@@ -135,6 +136,7 @@ func NewAutoInterface(name string, config *common.InterfaceConfig) (*AutoInterfa
 		peerJobInterval:    PEER_JOB_INTERVAL,
 		peeringTimeout:     PEERING_TIMEOUT,
 		mcastEchoTimeout:   MCAST_ECHO_TIMEOUT,
+		done:               make(chan struct{}),
 	}
 
 	debug.Log(debug.DEBUG_INFO, "AutoInterface configured", "name", name, "group", groupID, "mcast_addr", mcastAddr)
@@ -170,6 +172,20 @@ func normalizeMulticastType(mtype string) string {
 }
 
 func (ai *AutoInterface) Start() error {
+	ai.Mutex.Lock()
+	// Only recreate done if it's nil or was closed
+	select {
+	case <-ai.done:
+		ai.done = make(chan struct{})
+		ai.stopOnce = sync.Once{}
+	default:
+		if ai.done == nil {
+			ai.done = make(chan struct{})
+			ai.stopOnce = sync.Once{}
+		}
+	}
+	ai.Mutex.Unlock()
+
 	interfaces, err := net.Interfaces()
 	if err != nil {
 		return fmt.Errorf("failed to list interfaces: %v", err)
@@ -186,7 +202,9 @@ func (ai *AutoInterface) Start() error {
 			continue
 		}
 
-		if err := ai.configureInterface(&iface); err != nil {
+		ifaceCopy := iface
+		// bearer:disable go_gosec_memory_memory_aliasing
+		if err := ai.configureInterface(&ifaceCopy); err != nil {
 			debug.Log(debug.DEBUG_VERBOSE, "Failed to configure interface", "name", iface.Name, "error", err)
 			continue
 		}
@@ -262,7 +280,7 @@ func (ai *AutoInterface) configureInterface(iface *net.Interface) error {
 		return fmt.Errorf("no link-local IPv6 address found")
 	}
 
-	ai.mutex.Lock()
+	ai.Mutex.Lock()
 	ai.adoptedInterfaces[iface.Name] = &AdoptedInterface{
 		name:          iface.Name,
 		linkLocalAddr: linkLocalAddr,
@@ -270,7 +288,7 @@ func (ai *AutoInterface) configureInterface(iface *net.Interface) error {
 	}
 	ai.linkLocalAddrs = append(ai.linkLocalAddrs, linkLocalAddr)
 	ai.multicastEchoes[iface.Name] = time.Now()
-	ai.mutex.Unlock()
+	ai.Mutex.Unlock()
 
 	if err := ai.startDiscoveryListener(iface); err != nil {
 		return fmt.Errorf("failed to start discovery listener: %v", err)
@@ -296,13 +314,13 @@ func (ai *AutoInterface) startDiscoveryListener(iface *net.Interface) error {
 		return err
 	}
 
-	if err := conn.SetReadBuffer(1024); err != nil {
+	if err := conn.SetReadBuffer(common.NUM_1024); err != nil {
 		debug.Log(debug.DEBUG_ERROR, "Failed to set discovery read buffer", "error", err)
 	}
 
-	ai.mutex.Lock()
+	ai.Mutex.Lock()
 	ai.discoveryServers[iface.Name] = conn
-	ai.mutex.Unlock()
+	ai.Mutex.Unlock()
 
 	go ai.handleDiscovery(conn, iface.Name)
 	debug.Log(debug.DEBUG_VERBOSE, "Discovery listener started", "interface", iface.Name, "addr", ai.mcastDiscoveryAddr)
@@ -331,9 +349,9 @@ func (ai *AutoInterface) startDataListener(iface *net.Interface) error {
 		debug.Log(debug.DEBUG_ERROR, "Failed to set data read buffer", "error", err)
 	}
 
-	ai.mutex.Lock()
+	ai.Mutex.Lock()
 	ai.interfaceServers[iface.Name] = conn
-	ai.mutex.Unlock()
+	ai.Mutex.Unlock()
 
 	go ai.handleData(conn, iface.Name)
 	debug.Log(debug.DEBUG_VERBOSE, "Data listener started", "interface", iface.Name, "addr", addr)
@@ -341,8 +359,18 @@ func (ai *AutoInterface) startDataListener(iface *net.Interface) error {
 }
 
 func (ai *AutoInterface) handleDiscovery(conn *net.UDPConn, ifaceName string) {
-	buf := make([]byte, 1024)
+	buf := make([]byte, common.NUM_1024)
 	for {
+		ai.Mutex.RLock()
+		done := ai.done
+		ai.Mutex.RUnlock()
+
+		select {
+		case <-done:
+			return
+		default:
+		}
+
 		n, remoteAddr, err := conn.ReadFromUDP(buf)
 		if err != nil {
 			if ai.IsOnline() {
@@ -365,6 +393,16 @@ func (ai *AutoInterface) handleDiscovery(conn *net.UDPConn, ifaceName string) {
 func (ai *AutoInterface) handleData(conn *net.UDPConn, ifaceName string) {
 	buf := make([]byte, ai.GetMTU())
 	for {
+		ai.Mutex.RLock()
+		done := ai.done
+		ai.Mutex.RUnlock()
+
+		select {
+		case <-done:
+			return
+		default:
+		}
+
 		n, _, err := conn.ReadFromUDP(buf)
 		if err != nil {
 			if ai.IsOnline() {
@@ -380,8 +418,8 @@ func (ai *AutoInterface) handleData(conn *net.UDPConn, ifaceName string) {
 }
 
 func (ai *AutoInterface) handlePeerAnnounce(addr *net.UDPAddr, ifaceName string) {
-	ai.mutex.Lock()
+	ai.Mutex.Lock()
-	defer ai.mutex.Unlock()
+	defer ai.Mutex.Unlock()
 
 	peerIP := addr.IP.String()
 
@@ -412,17 +450,22 @@ func (ai *AutoInterface) announceLoop() {
 	ticker := time.NewTicker(ai.announceInterval)
 	defer ticker.Stop()
 
-	for range ticker.C {
+	for {
-		if !ai.IsOnline() {
+		select {
+		case <-ticker.C:
+			if !ai.IsOnline() {
+				return
+			}
+			ai.sendPeerAnnounce()
+		case <-ai.done:
 			return
 		}
-		ai.sendPeerAnnounce()
 	}
 }
 
 func (ai *AutoInterface) sendPeerAnnounce() {
-	ai.mutex.RLock()
+	ai.Mutex.RLock()
-	defer ai.mutex.RUnlock()
+	defer ai.Mutex.RUnlock()
 
 	for ifaceName, adoptedIface := range ai.adoptedInterfaces {
 		mcastAddr := &net.UDPAddr{
@@ -452,33 +495,38 @@ func (ai *AutoInterface) peerJobs() {
 	ticker := time.NewTicker(ai.peerJobInterval)
 	defer ticker.Stop()
 
-	for range ticker.C {
+	for {
-		if !ai.IsOnline() {
+		select {
+		case <-ticker.C:
+			if !ai.IsOnline() {
+				return
+			}
+
+			ai.Mutex.Lock()
+			now := time.Now()
+
+			for peerKey, peer := range ai.peers {
+				if now.Sub(peer.lastHeard) > ai.peeringTimeout {
+					delete(ai.peers, peerKey)
+					debug.Log(debug.DEBUG_VERBOSE, "Removed timed out peer", "peer", peerKey)
+				}
+			}
+
+			for ifaceName, echoTime := range ai.multicastEchoes {
+				if now.Sub(echoTime) > ai.mcastEchoTimeout {
+					if _, exists := ai.timedOutInterfaces[ifaceName]; !exists {
+						debug.Log(debug.DEBUG_INFO, "Interface timed out", "interface", ifaceName)
+						ai.timedOutInterfaces[ifaceName] = now
+					}
+				} else {
+					delete(ai.timedOutInterfaces, ifaceName)
+				}
+			}
+
+			ai.Mutex.Unlock()
+		case <-ai.done:
 			return
 		}
-
-		ai.mutex.Lock()
-		now := time.Now()
-
-		for peerKey, peer := range ai.peers {
-			if now.Sub(peer.lastHeard) > ai.peeringTimeout {
-				delete(ai.peers, peerKey)
-				debug.Log(debug.DEBUG_VERBOSE, "Removed timed out peer", "peer", peerKey)
-			}
-		}
-
-		for ifaceName, echoTime := range ai.multicastEchoes {
-			if now.Sub(echoTime) > ai.mcastEchoTimeout {
-				if _, exists := ai.timedOutInterfaces[ifaceName]; !exists {
-					debug.Log(debug.DEBUG_INFO, "Interface timed out", "interface", ifaceName)
-					ai.timedOutInterfaces[ifaceName] = now
-				}
-			} else {
-				delete(ai.timedOutInterfaces, ifaceName)
-			}
-		}
-
-		ai.mutex.Unlock()
 	}
 }
 
@@ -487,8 +535,8 @@ func (ai *AutoInterface) Send(data []byte, address string) error {
 		return fmt.Errorf("interface offline")
 	}
 
-	ai.mutex.RLock()
+	ai.Mutex.RLock()
-	defer ai.mutex.RUnlock()
+	defer ai.Mutex.RUnlock()
 
 	if len(ai.peers) == 0 {
 		debug.Log(debug.DEBUG_TRACE, "No peers available for sending")
@@ -526,9 +574,7 @@ func (ai *AutoInterface) Send(data []byte, address string) error {
 }
 
 func (ai *AutoInterface) Stop() error {
-	ai.mutex.Lock()
+	ai.Mutex.Lock()
-	defer ai.mutex.Unlock()
-
 	ai.Online = false
 	ai.IN = false
 	ai.OUT = false
@@ -544,6 +590,13 @@ func (ai *AutoInterface) Stop() error {
 	if ai.outboundConn != nil {
 		ai.outboundConn.Close() // #nosec G104
 	}
+	ai.Mutex.Unlock()
+
+	ai.stopOnce.Do(func() {
+		if ai.done != nil {
+			close(ai.done)
+		}
+	})
 
 	debug.Log(debug.DEBUG_INFO, "AutoInterface stopped")
 	return nil