Add stop methods and improve udp implementation

client/firewall/uspfilter/allow_netbird.go

@@ -30,6 +30,10 @@ func (m *Manager) Reset(stateManager *statemanager.Manager) error {
 		m.tcpTracker = conntrack.NewTCPTracker(conntrack.DefaultTCPTimeout)
 	}
 
+	if m.forwarder != nil {
+		m.forwarder.Stop()
+	}
+
 	if m.nativeFirewall != nil {
 		return m.nativeFirewall.Reset(stateManager)
 	}

client/firewall/uspfilter/allow_netbird_windows.go

@@ -42,6 +42,10 @@ func (m *Manager) Reset(*statemanager.Manager) error {
 		m.tcpTracker = conntrack.NewTCPTracker(conntrack.DefaultTCPTimeout)
 	}
 
+	if m.forwarder != nil {
+		m.forwarder.Stop()
+	}
+
 	if !isWindowsFirewallReachable() {
 		return nil
 	}

client/firewall/uspfilter/forwarder/forwarder.go

@@ -1,6 +1,7 @@
 package forwarder
 
 import (
+	"context"
 	"fmt"
 
 	log "github.com/sirupsen/logrus"
@@ -24,9 +25,12 @@ type Forwarder struct {
 	stack        *stack.Stack
 	endpoint     *endpoint
 	udpForwarder *udpForwarder
+	ctx          context.Context
+	cancel       context.CancelFunc
 }
 
 func New(iface common.IFaceMapper) (*Forwarder, error) {
+
 	s := stack.New(stack.Options{
 		NetworkProtocols: []stack.NetworkProtocolFactory{ipv4.NewProtocol},
 		TransportProtocols: []stack.TransportProtocolFactory{
@@ -85,10 +89,13 @@ func New(iface common.IFaceMapper) (*Forwarder, error) {
 		},
 	})
 
+	ctx, cancel := context.WithCancel(context.Background())
 	f := &Forwarder{
 		stack:        s,
 		endpoint:     endpoint,
 		udpForwarder: newUDPForwarder(),
+		ctx:          ctx,
+		cancel:       cancel,
 	}
 
 	// Set up TCP forwarder
@@ -118,3 +125,17 @@ func (f *Forwarder) InjectIncomingPacket(payload []byte) error {
 	}
 	return nil
 }
+
+// Stop gracefully shuts down the forwarder
+func (f *Forwarder) Stop() error {
+	f.cancel()
+
+	if f.udpForwarder != nil {
+		f.udpForwarder.Stop()
+	}
+
+	f.stack.Close()
+	f.stack.Wait()
+
+	return nil
+}

client/firewall/uspfilter/forwarder/tcp.go

@@ -1,10 +1,10 @@
 package forwarder
 
 import (
+	"context"
 	"fmt"
 	"io"
 	"net"
-	"sync"
 
 	log "github.com/sirupsen/logrus"
 	"gvisor.dev/gvisor/pkg/tcpip/adapters/gonet"
@@ -20,9 +20,7 @@ func (f *Forwarder) handleTCP(r *tcp.ForwarderRequest) {
 	dstPort := id.LocalPort
 	dialAddr := fmt.Sprintf("%s:%d", dstAddr.String(), dstPort)
 
-	// Dial the destination first
+	outConn, err := (&net.Dialer{}).DialContext(f.ctx, "tcp", dialAddr)
-	dialer := net.Dialer{}
-	outConn, err := dialer.Dial("tcp", dialAddr)
 	if err != nil {
 		r.Complete(true)
 		return
@@ -40,8 +38,7 @@ func (f *Forwarder) handleTCP(r *tcp.ForwarderRequest) {
 		return
 	}
 
-	// Now that we've successfully connected to the destination,
+	// Complete the handshake
-	// we can complete the incoming connection
 	r.Complete(false)
 
 	inConn := gonet.NewTCPConn(&wq, ep)
@@ -59,24 +56,35 @@ func (f *Forwarder) proxyTCP(inConn *gonet.TCPConn, outConn net.Conn) {
 		}
 	}()
 
-	var wg sync.WaitGroup
+	// Create context for managing the proxy goroutines
-	wg.Add(2)
+	ctx, cancel := context.WithCancel(f.ctx)
+	defer cancel()
+
+	errChan := make(chan error, 2)
 
 	go func() {
-		defer wg.Done()
+		n, err := io.Copy(outConn, inConn)
-		_, err := io.Copy(outConn, inConn)
+		if err != nil && !isClosedError(err) {
-		if err != nil {
+			log.Errorf("proxyTCP: inbound->outbound copy error after %d bytes: %v", n, err)
-			log.Errorf("proxyTCP: copy error: %v", err)
 		}
+		errChan <- err
 	}()
 
 	go func() {
-		defer wg.Done()
+		n, err := io.Copy(inConn, outConn)
-		_, err := io.Copy(inConn, outConn)
+		if err != nil && !isClosedError(err) {
-		if err != nil {
+			log.Errorf("proxyTCP: outbound->inbound copy error after %d bytes: %v", n, err)
-			log.Errorf("proxyTCP: copy error: %v", err)
 		}
+		errChan <- err
 	}()
 
-	wg.Wait()
+	select {
+	case <-ctx.Done():
+		return
+	case err := <-errChan:
+		if err != nil && !isClosedError(err) {
+			log.Errorf("proxyTCP: copy error: %v", err)
+		}
+		return
+	}
 }

client/firewall/uspfilter/forwarder/udp.go

@@ -1,6 +1,8 @@
 package forwarder
 
 import (
+	"context"
+	"errors"
 	"fmt"
 	"net"
 	"sync"
@@ -8,63 +10,113 @@ import (
 
 	log "github.com/sirupsen/logrus"
 	"gvisor.dev/gvisor/pkg/tcpip/adapters/gonet"
+	"gvisor.dev/gvisor/pkg/tcpip/stack"
 	"gvisor.dev/gvisor/pkg/tcpip/transport/udp"
 	"gvisor.dev/gvisor/pkg/waiter"
 )
 
 const (
 	udpTimeout    = 60 * time.Second
+	maxPacketSize = 65535
 )
 
 type udpPacketConn struct {
 	conn     *gonet.UDPConn
 	outConn  net.Conn
 	lastTime time.Time
+	cancel   context.CancelFunc
 }
 
 type udpForwarder struct {
 	sync.RWMutex
-	conns map[string]*udpPacketConn
+	conns   map[stack.TransportEndpointID]*udpPacketConn
+	bufPool sync.Pool
+	ctx     context.Context
+	cancel  context.CancelFunc
 }
 
 func newUDPForwarder() *udpForwarder {
+	ctx, cancel := context.WithCancel(context.Background())
 	f := &udpForwarder{
-		conns: make(map[string]*udpPacketConn),
+		conns:  make(map[stack.TransportEndpointID]*udpPacketConn),
+		ctx:    ctx,
+		cancel: cancel,
+		bufPool: sync.Pool{
+			New: func() any {
+				b := make([]byte, maxPacketSize)
+				return &b
+			},
+		},
 	}
 	go f.cleanup()
 	return f
 }
 
+// Stop stops the UDP forwarder and all active connections
+func (f *udpForwarder) Stop() {
+	f.cancel()
+
+	f.Lock()
+	defer f.Unlock()
+
+	for id, conn := range f.conns {
+		conn.cancel()
+		if err := conn.conn.Close(); err != nil {
+			log.Errorf("forwarder: UDP conn close error for %v: %v", id, err)
+		}
+		if err := conn.outConn.Close(); err != nil {
+			log.Errorf("forwarder: UDP outConn close error for %v: %v", id, err)
+		}
+		delete(f.conns, id)
+	}
+}
+
 // cleanup periodically removes idle UDP connections
 func (f *udpForwarder) cleanup() {
 	ticker := time.NewTicker(time.Minute)
 	defer ticker.Stop()
 
-	for range ticker.C {
+	for {
+		select {
+		case <-f.ctx.Done():
+			return
+		case <-ticker.C:
 			f.Lock()
 			now := time.Now()
-		for addr, conn := range f.conns {
+			for id, conn := range f.conns {
 				if now.Sub(conn.lastTime) > udpTimeout {
-				conn.conn.Close()
+					conn.cancel()
-				conn.outConn.Close()
+					if err := conn.conn.Close(); err != nil {
-				delete(f.conns, addr)
+						log.Errorf("forwarder: UDP conn close error for %v: %v", id, err)
+					}
+					if err := conn.outConn.Close(); err != nil {
+						log.Errorf("forwarder: UDP outConn close error for %v: %v", id, err)
+					}
+					delete(f.conns, id)
+					log.Debugf("forwarder: cleaned up idle UDP connection %v", id)
 				}
 			}
 			f.Unlock()
 		}
 	}
+}
 
 // handleUDP is called by the UDP forwarder for new packets
 func (f *Forwarder) handleUDP(r *udp.ForwarderRequest) {
 	id := r.ID()
 	dstAddr := fmt.Sprintf("%s:%d", id.LocalAddress.String(), id.LocalPort)
 
+	if f.ctx.Err() != nil {
+		log.Debug("forwarder: context done, dropping UDP packet")
+		return
+	}
+
 	// Create wait queue for blocking syscalls
 	wq := waiter.Queue{}
 
 	ep, err := r.CreateEndpoint(&wq)
 	if err != nil {
-		log.Errorf("Create UDP endpoint error: %v", err)
+		log.Errorf("forwarder: failed to create UDP endpoint: %v", err)
 		return
 	}
 
@@ -72,82 +124,115 @@ func (f *Forwarder) handleUDP(r *udp.ForwarderRequest) {
 
 	// Try to get existing connection or create a new one
 	f.udpForwarder.Lock()
-	pConn, exists := f.udpForwarder.conns[dstAddr]
+	defer f.udpForwarder.Unlock()
+
+	pConn, exists := f.udpForwarder.conns[id]
 	if !exists {
-		outConn, err := net.Dial("udp", dstAddr)
+		outConn, err := (&net.Dialer{}).DialContext(f.ctx, "udp", dstAddr)
 		if err != nil {
-			f.udpForwarder.Unlock()
 			if err := inConn.Close(); err != nil {
-				log.Errorf("forwader: UDP inConn close error: %v", err)
+				log.Errorf("forwarder: UDP inConn close error for %v: %v", id, err)
 			}
-			log.Errorf("forwarder> UDP dial error: %v", err)
+			log.Errorf("forwarder: UDP dial error for %v: %v", id, err)
 			return
 		}
 
+		connCtx, connCancel := context.WithCancel(f.ctx)
 		pConn = &udpPacketConn{
 			conn:     inConn,
 			outConn:  outConn,
 			lastTime: time.Now(),
+			cancel:   connCancel,
 		}
-		f.udpForwarder.conns[dstAddr] = pConn
+		f.udpForwarder.conns[id] = pConn
 
-		go f.proxyUDP(pConn, dstAddr)
+		go f.proxyUDP(connCtx, pConn, id)
 	}
-	f.udpForwarder.Unlock()
 }
 
-func (f *Forwarder) proxyUDP(pConn *udpPacketConn, dstAddr string) {
+func (f *Forwarder) proxyUDP(ctx context.Context, pConn *udpPacketConn, id stack.TransportEndpointID) {
 	defer func() {
+		pConn.cancel()
 		if err := pConn.conn.Close(); err != nil {
-			log.Errorf("forwarder: inConn close error: %v", err)
+			log.Errorf("forwarder: UDP inConn close error for %v: %v", id, err)
 		}
 		if err := pConn.outConn.Close(); err != nil {
-			log.Errorf("forwarder: outConn close error: %v", err)
+			log.Errorf("forwarder: UDP outConn close error for %v: %v", id, err)
 		}
-	}()
 
-	var wg sync.WaitGroup
-	wg.Add(2)
-
-	// Handle outbound to inbound traffic
-	go func() {
-		defer wg.Done()
-		f.copyUDP(pConn.conn, pConn.outConn, dstAddr, "outbound->inbound")
-	}()
-
-	// Handle inbound to outbound traffic
-	go func() {
-		defer wg.Done()
-		f.copyUDP(pConn.outConn, pConn.conn, dstAddr, "inbound->outbound")
-	}()
-
-	wg.Wait()
-
-	// Clean up the connection from the map
 		f.udpForwarder.Lock()
-	delete(f.udpForwarder.conns, dstAddr)
+		delete(f.udpForwarder.conns, id)
 		f.udpForwarder.Unlock()
+	}()
+
+	errChan := make(chan error, 2)
+
+	go func() {
+		errChan <- f.copyUDP(ctx, pConn.conn, pConn.outConn, id, "outbound->inbound")
+	}()
+
+	go func() {
+		errChan <- f.copyUDP(ctx, pConn.outConn, pConn.conn, id, "inbound->outbound")
+	}()
+
+	select {
+	case <-ctx.Done():
+		return
+	case err := <-errChan:
+		if err != nil && !isClosedError(err) {
+			log.Errorf("forwader: UDP proxy error for %v: %v", id, err)
+		}
+		return
+	}
+}
+
+func (f *Forwarder) copyUDP(ctx context.Context, dst net.Conn, src net.Conn, id stack.TransportEndpointID, direction string) error {
+	bufp := f.udpForwarder.bufPool.Get().(*[]byte)
+	defer f.udpForwarder.bufPool.Put(bufp)
+	buffer := *bufp
+
+	if err := src.SetReadDeadline(time.Now().Add(udpTimeout)); err != nil {
+		return fmt.Errorf("set read deadline: %w", err)
+	}
+	if err := src.SetWriteDeadline(time.Now().Add(udpTimeout)); err != nil {
+		return fmt.Errorf("set write deadline: %w", err)
 	}
 
-func (f *Forwarder) copyUDP(dst net.Conn, src net.Conn, dstAddr, direction string) {
-	buffer := make([]byte, 65535)
 	for {
+		select {
+		case <-ctx.Done():
+			return ctx.Err()
+		default:
 			n, err := src.Read(buffer)
 			if err != nil {
-			log.Errorf("UDP %s read error: %v", direction, err)
+				if isTimeout(err) {
-			return
+					continue
+				}
+				return fmt.Errorf("read from %s: %w", direction, err)
 			}
 
 			_, err = dst.Write(buffer[:n])
 			if err != nil {
-			log.Errorf("UDP %s write error: %v", direction, err)
+				return fmt.Errorf("write to %s: %w", direction, err)
-			continue
 			}
 
 			f.udpForwarder.Lock()
-		if conn, ok := f.udpForwarder.conns[dstAddr]; ok {
+			if conn, ok := f.udpForwarder.conns[id]; ok {
 				conn.lastTime = time.Now()
 			}
 			f.udpForwarder.Unlock()
 		}
 	}
+}
+
+func isClosedError(err error) bool {
+	return errors.Is(err, net.ErrClosed) || errors.Is(err, context.Canceled)
+}
+
+func isTimeout(err error) bool {
+	var netErr net.Error
+	if errors.As(err, &netErr) {
+		return netErr.Timeout()
+	}
+	return false
+}