HTTP and Listener improvements and bugfixes (#17)

* listener revamp

* improvements to conn lifetimes

http/httpraw/header.go

@@ -111,6 +111,11 @@ func (h *Header) TryParse(asResponse bool) (needMoreData bool, err error) {
 	return err == errNeedMore, err
 }
 
+// ParsingSuccess returns true if TryParse was successful, that is to say it returned needMoreData==false and err==nil.
+func (h *Header) ParsingSuccess() bool {
+	return h.flags.hasAny(flagDoneParsingHeader)
+}
+
 // ReadFromLimited reads at most maxBytesToRead from reader and appends them to underlying buffer.
 // Used to accumulate HTTP header for later parsing with [Header.TryParse].
 // If read is successful (read length>0) and reader returns [io.EOF] then ReadFromLimited will return a nil error.
@@ -157,6 +162,14 @@ func (h *Header) ReadFromBytes(b []byte) (int, error) {
 	return len(b), nil
 }
 
+// BufferReceived returns the amoung of bytes read during calls to Read* methods.
+func (h *Header) BufferReceived() int {
+	if h.flags.hasAny(flagMangledBuffer | flagOOMReached) {
+		return 0
+	}
+	return len(h.hbuf.buf)
+}
+
 // BufferParsed returns the amount of bytes parsed during a call to Parse* methods.
 // If the Parse* method completed without error then BufferParsed returns the header's length including the final "\r\n\r\n" text.
 // BufferParsed returns 0 if the buffer is invalid/mangled or if no header data has been parsed succesfully.
@@ -321,11 +334,15 @@ func (h *Header) getNonEmptyValue(s headerSlice) []byte {
 
 // AppendRequest appends the request header representation to the buffer and returns the result.
 func (h *Header) AppendRequest(dst []byte) ([]byte, error) {
+	proto := h.Protocol()
 	if h.flags.hasAny(flagOOMReached) {
 		return dst, errOOM
-	} else if h.requestURI.len == 0 || h.proto.len == 0 || h.method.len == 0 {
-		return dst, errors.New("need method/protocol/request URI to create request header")
+	} else if h.requestURI.len == 0 || h.method.len == 0 {
+		return dst, errors.New("need method/request URI to create request header")
+	} else if len(proto) == 0 {
+		return dst, errNoProto
 	}
+
 	method := h.Method()
 	if len(method) == 0 {
 		dst = append(dst, methodGet...)
@@ -333,7 +350,6 @@ func (h *Header) AppendRequest(dst []byte) ([]byte, error) {
 		dst = append(dst, method...)
 	}
 	uri := h.RequestURI()
-	proto := h.Protocol()
 
 	dst = append(dst, ' ')
 	dst = append(dst, uri...)
@@ -348,12 +364,18 @@ func (h *Header) AppendRequest(dst []byte) ([]byte, error) {
 
 // AppendResponse appends the response header representation to the buffer and returns the result.
 func (h *Header) AppendResponse(dst []byte) ([]byte, error) {
+	proto := h.Protocol()
 	if h.flags.hasAny(flagOOMReached) {
 		return dst, errOOM
 	} else if h.statusCode.len == 0 || h.statusText.len == 0 {
 		return dst, errors.New("invalid status code or text")
+	} else if len(proto) == 0 {
+		return dst, errNoProto
 	}
 	code, text := h.Status()
+
+	dst = append(dst, proto...)
+	dst = append(dst, ' ')
 	dst = append(dst, code...)
 	dst = append(dst, ' ')
 	dst = append(dst, text...)

http/httpraw/parse.go

@@ -8,6 +8,7 @@ import (
 )
 
 var (
+	errNoProto     = errors.New("missing protocol, HTTP/0.9 unsupported")
 	errNeedMore    = errors.New("need more data: cannot find trailing lf")
 	errUnparsed    = errors.New("need to finish parsing")
 	errInvalidName = errors.New("invalid header name")
@@ -250,7 +251,7 @@ func (h *Header) appendSlice(value string) headerSlice {
 			h.flags |= flagOOMReached
 			return headerSlice{}
 		}
-		h.hbuf.buf = slices.Grow(h.hbuf.buf, len(value))
+		h.hbuf.buf = slices.Grow(h.hbuf.buf, len(value)+1) // Grow 1 beyond due to slice validity.
 	}
 	h.flags |= flagMangledBuffer
 	return h.hbuf.mustAppendSlice(value)

internet/pcap/capture_test.go

@@ -30,9 +30,13 @@ func TestCap(t *testing.T) {
 		Flags:   tcp.FlagFIN, //tcp.FlagSYN | tcp.FlagACK | tcp.FlagPSH,
 	})
 	var hdr httpraw.Header
+	hdr.SetProtocol("HTTP/1.1")
 	hdr.SetStatus("200", "OK")
 	hdr.Set("Cookie", "ABC=123")
-	pkt, _ = hdr.AppendResponse(pkt)
+	pkt, err := hdr.AppendResponse(pkt)
+	if err != nil {
+		t.Fatal(err)
+	}
 	pkt = append(pkt, httpBody...)
 	var pbreak PacketBreakdown
 	frames, err := pbreak.CaptureEthernet(nil, pkt, 0)
@@ -233,12 +237,12 @@ func TestRightAlignedFields(t *testing.T) {
 // with right-aligned fields that have trailing bits.
 func TestAppendFieldRightAligned(t *testing.T) {
 	testCases := []struct {
-		name           string
-		pkt            []byte
-		fieldBitStart  int
-		bitlen         int
-		rightAligned   bool
-		wantData       []byte
+		name          string
+		pkt           []byte
+		fieldBitStart int
+		bitlen        int
+		rightAligned  bool
+		wantData      []byte
 	}{
 		{
 			// IPv6 Traffic Class: bits 4-11 (8 bits spanning bytes 0-1)

internet/tcplistener_test.go

@@ -47,7 +47,7 @@ func TestListener_SingleConnection(t *testing.T) {
 	if listener.NumberOfReadyToAccept() != 1 {
 		t.Fatalf("after handshake: expected 1 ready, got %d", listener.NumberOfReadyToAccept())
 	}
-	acceptedConn, err := listener.TryAccept()
+	acceptedConn, _, err := listener.TryAccept()
 	if err != nil {
 		t.Fatalf("TryAccept: %v", err)
 	}
@@ -91,7 +91,7 @@ func TestListener_AcceptAfterEstablished(t *testing.T) {
 	if listener.NumberOfReadyToAccept() != 1 {
 		t.Fatalf("after client1 handshake: expected 1 ready, got %d", listener.NumberOfReadyToAccept())
 	}
-	accepted1, err := listener.TryAccept()
+	accepted1, _, err := listener.TryAccept()
 	if err != nil {
 		t.Fatalf("TryAccept client1: %v", err)
 	} else if listener.NumberOfReadyToAccept() != 0 {
@@ -115,7 +115,7 @@ func TestListener_AcceptAfterEstablished(t *testing.T) {
 	if listener.NumberOfReadyToAccept() != 1 {
 		t.Fatalf("after client2 handshake: expected 1 ready, got %d", listener.NumberOfReadyToAccept())
 	}
-	accepted2, err := listener.TryAccept()
+	accepted2, _, err := listener.TryAccept()
 	if err != nil {
 		t.Fatalf("TryAccept client2: %v", err)
 	} else if listener.NumberOfReadyToAccept() != 0 {
@@ -174,7 +174,7 @@ func TestListener_MultiConn(t *testing.T) {
 	// Accept all connections.
 	for i := 0; i < numClients; i++ {
 		var err error
-		acceptedConns[i], err = listener.TryAccept()
+		acceptedConns[i], _, err = listener.TryAccept()
 		if err != nil {
 			t.Fatalf("TryAccept client %d: %v", i, err)
 		}
@@ -369,16 +369,16 @@ func newMockTCPPool(n, queuesize, bufsize int) *mockTCPPool {
 	return pool
 }
 
-func (p *mockTCPPool) GetTCP() (*tcp.Conn, tcp.Value) {
+func (p *mockTCPPool) GetTCP() (*tcp.Conn, any, tcp.Value) {
 	for i := range p.conns {
 		if !p.acquired[i] {
 			p.acquired[i] = true
 			p.nextISS += 1000
 			p.naqcuired++
-			return &p.conns[i], p.nextISS
+			return &p.conns[i], nil, p.nextISS
 		}
 	}
-	return nil, 0
+	return nil, nil, 0
 }
 
 func (p *mockTCPPool) PutTCP(conn *tcp.Conn) {

tcp/listener.go

@@ -13,7 +13,7 @@ import (
 
 // pool is a [sync.Pool] like
 type pool interface {
-	GetTCP() (*Conn, Value)
+	GetTCP() (*Conn, any, Value)
 	PutTCP(*Conn)
 }
 
@@ -21,15 +21,21 @@ type Listener struct {
 	connID uint64
 	mu     sync.Mutex
 	// incoming stores connections that are potential candidates for acceptance.
-	incoming []*Conn
+	incoming []handler
 	// accepted stores all connections that have been accepted and are open.
-	accepted   []*Conn
+	accepted   []handler
 	port       uint16
-	poolGet    func() (*Conn, Value)
+	poolGet    func() (*Conn, any, Value)
 	poolReturn func(*Conn)
 	logger
 }
 
+type handler struct {
+	conn     *Conn
+	id       uint64
+	userData any
+}
+
 func (listener *Listener) reset(port uint16, tcppool pool) {
 	listener.accepted = listener.accepted[:0]
 	listener.incoming = listener.incoming[:0]
@@ -89,7 +95,8 @@ func (listener *Listener) NumberOfReadyToAccept() (nready int) {
 	if listener.isClosed() {
 		return 0
 	}
-	for _, conn := range listener.incoming {
+	for i := range listener.incoming {
+		conn := listener.incoming[i].conn
 		if conn == nil || conn.State() != StateEstablished {
 			continue
 		}
@@ -99,27 +106,29 @@ func (listener *Listener) NumberOfReadyToAccept() (nready int) {
 }
 
 // TryAccept polls the list of ready connections that have been established
-func (listener *Listener) TryAccept() (*Conn, error) {
+func (listener *Listener) TryAccept() (*Conn, any, error) {
 	listener.mu.Lock()
 	defer listener.mu.Unlock()
 	if listener.isClosed() {
-		return nil, net.ErrClosed
+		return nil, nil, net.ErrClosed
 	}
 	listener.debug("listener:tryaccept", slog.Uint64("port", uint64(listener.port)))
 	listener.maintainConns()
-	for i, conn := range listener.incoming {
+	for i := range listener.incoming {
+		conn := listener.incoming[i].conn
 		if conn == nil || conn.State() != StateEstablished {
 			continue
 		}
-		listener.accepted = append(listener.accepted, conn)
-		listener.incoming[i] = nil // discard from ready.
-		return conn, nil
+		userData := listener.incoming[i].userData
+		listener.accepted = append(listener.accepted, listener.incoming[i])
+		listener.incoming[i] = handler{} // discard from ready.
+		return conn, userData, nil
 	}
-	return nil, errors.New("no conns available")
+	return nil, nil, errors.New("no conns available")
 }
 
 // Encapsulate implements [StackNode].
-func (listener *Listener) Encapsulate(carrierData []byte, offsetToIP, offsetToFrame int) (int, error) {
+func (listener *Listener) Encapsulate(carrierData []byte, offsetToIP, offsetToFrame int) (n int, err error) {
 	listener.mu.Lock()
 	defer listener.mu.Unlock()
 	if listener.isClosed() {
@@ -127,7 +136,8 @@ func (listener *Listener) Encapsulate(carrierData []byte, offsetToIP, offsetToFr
 	}
 	//listener.trace("listener:encaps", slog.Uint64("port", uint64(listener.port)))
 	// First try incoming connections (for handshake SYN-ACK).
-	for i, conn := range listener.incoming {
+	for i := range listener.incoming {
+		conn := listener.incoming[i].conn
 		if conn == nil || conn.State() == StateEstablished {
 			// Nil or already established.
 			continue
@@ -143,21 +153,24 @@ func (listener *Listener) Encapsulate(carrierData []byte, offsetToIP, offsetToFr
 		return n, err
 	}
 	// Then try accepted connections.
-	for i, conn := range listener.accepted {
+	for i := range listener.accepted {
+		conn := listener.accepted[i].conn
 		if conn == nil {
 			continue
-		}
-		n, err := conn.Encapsulate(carrierData, offsetToIP, offsetToFrame)
-		if err != nil {
-			err = listener.maintainConn(listener.accepted, i, err)
-		}
-		if n == 0 {
+		} else if conn.h.connid != listener.accepted[i].id {
+			listener.returnAccepted(i)
 			continue
 		}
-		listener.debug("listener:encaps", slog.Uint64("port", uint64(listener.port)), slog.Int("plen", n), slog.String("list", "accepted"))
-		return n, err
+		n, err = conn.Encapsulate(carrierData, offsetToIP, offsetToFrame)
+		if n > 0 {
+			listener.debug("listener:encaps", slog.Uint64("port", uint64(listener.port)), slog.Int("plen", n), slog.String("list", "accepted"))
+			break
+		} else if err == net.ErrClosed {
+			listener.returnAccepted(i)
+			err = nil
+		}
 	}
-	return 0, nil
+	return n, err
 }
 
 // Demux implements [StackNode].
@@ -198,7 +211,7 @@ func (listener *Listener) Demux(carrierData []byte, tcpFrameOffset int) error {
 	if flags != FlagSYN {
 		return lneto.ErrPacketDrop // Not a synchronizing packet, drop it.
 	}
-	conn, iss := listener.poolGet()
+	conn, userData, iss := listener.poolGet()
 	if conn == nil {
 		slog.Error("tcpListener:no-free-conn")
 		return lneto.ErrPacketDrop
@@ -215,15 +228,19 @@ func (listener *Listener) Demux(carrierData []byte, tcpFrameOffset int) error {
 		slog.Error("Listener:demux", slog.String("err", err.Error()))
 		return lneto.ErrPacketDrop
 	}
-	listener.incoming = append(listener.incoming, conn)
+	listener.incoming = append(listener.incoming, handler{
+		conn:     conn,
+		id:       *conn.ConnectionID(),
+		userData: userData,
+	})
 	listener.debug("tcplistener:demux-new", slog.Uint64("lport", uint64(listener.port)), slog.Uint64("rport", uint64(src)))
 	return nil
 }
 
-func (listener *Listener) tryDemux(conns []*Conn, remotePort uint16, remoteAddr, carrierData []byte, tcpFrameOffset int) (demuxed bool, err error) {
+func (listener *Listener) tryDemux(conns []handler, remotePort uint16, remoteAddr, carrierData []byte, tcpFrameOffset int) (demuxed bool, err error) {
 	idx := getConn(conns, remotePort, remoteAddr)
 	if idx >= 0 {
-		err := conns[idx].Demux(carrierData, tcpFrameOffset)
+		err := conns[idx].conn.Demux(carrierData, tcpFrameOffset)
 		if err != nil {
 			err = listener.maintainConn(conns, idx, err)
 		}
@@ -239,21 +256,22 @@ func (listener *Listener) isClosed() bool {
 func (listener *Listener) maintainConns() {
 	listener.accepted = internal.DeleteZeroed(listener.accepted)
 	for i := range listener.incoming {
-		if listener.incoming[i] == nil {
+		conn := listener.incoming[i].conn
+		if conn == nil {
 			continue
 		}
-		state := listener.incoming[i].State()
+		state := conn.State()
 		if state > StateEstablished || state.IsClosed() {
 			// Something went wrong in handshake or pool aborted/closed the connection.
-			listener.poolReturn(listener.incoming[i])
-			listener.incoming[i] = nil
+			listener.returnIncoming(i)
 		}
 	}
 	listener.incoming = internal.DeleteZeroed(listener.incoming)
 }
 
-func getConn(conns []*Conn, remotePort uint16, remoteAddr []byte) int {
-	for i, conn := range conns {
+func getConn(conns []handler, remotePort uint16, remoteAddr []byte) int {
+	for i := range conns {
+		conn := conns[i].conn
 		if conn == nil {
 			continue
 		}
@@ -266,11 +284,20 @@ func getConn(conns []*Conn, remotePort uint16, remoteAddr []byte) int {
 	return -1
 }
 
-func (listener *Listener) maintainConn(conns []*Conn, idx int, err error) error {
+func (listener *Listener) maintainConn(conns []handler, idx int, err error) error {
 	if err == net.ErrClosed {
-		listener.poolReturn(conns[idx])
-		conns[idx] = nil
+		listener.returnAccepted(idx)
 		return nil // avoid closing listener entirely.
 	}
 	return err
 }
+
+func (listener *Listener) returnAccepted(idx int) {
+	listener.poolReturn(listener.accepted[idx].conn)
+	listener.accepted[idx] = handler{}
+}
+
+func (listener *Listener) returnIncoming(idx int) {
+	listener.poolReturn(listener.incoming[idx].conn)
+	listener.incoming[idx] = handler{}
+}

x/xnet/tcppool.go

@@ -15,6 +15,7 @@ type TCPPool struct {
 	mu             sync.Mutex
 	naqcuired      int
 	conns          []tcp.Conn
+	userData       []any
 	acquiredAt     []time.Time
 	closingAt      []time.Time
 	abortedAt      []time.Time
@@ -31,9 +32,11 @@ func _() {
 }
 
 type TCPPoolConfig struct {
-	PoolSize   int
-	QueueSize  int
-	BufferSize int
+	PoolSize  int
+	QueueSize int
+	TxBufSize int
+	RxBufSize int
+
 	Logger     *slog.Logger
 	ConnLogger *slog.Logger
 	Now        func() time.Time
@@ -43,6 +46,8 @@ type TCPPoolConfig struct {
 	// ClosingTimeout sets the timeout for a TCP connection to close and be returned to Pool.
 	// If the connection is not closed in this time it will be aborted by the pool.
 	ClosingTimeout time.Duration
+	// NewUserData is used to create user data used for each individual TCP connection and returned on GetTCP.
+	NewUserData func() any
 }
 
 func NewTCPPool(cfg TCPPoolConfig) (*TCPPool, error) {
@@ -50,29 +55,34 @@ func NewTCPPool(cfg TCPPoolConfig) (*TCPPool, error) {
 		return nil, errors.New("invalid timeout")
 	}
 	n := cfg.PoolSize
-	bufsize := cfg.BufferSize
 	pool := &TCPPool{
 		acquiredAt:     make([]time.Time, n),
 		closingAt:      make([]time.Time, n),
 		abortedAt:      make([]time.Time, n),
 		conns:          make([]tcp.Conn, n),
+		userData:       make([]any, n),
 		_now:           cfg.Now,
 		estbTimeout:    cfg.EstablishedTimeout,
 		closingTimeout: cfg.ClosingTimeout,
 		logger:         cfg.Logger,
 	}
-	bufSpace := make([]byte, 2*n*bufsize)
+	allocPerConn := cfg.TxBufSize + cfg.RxBufSize
+	bufSpace := make([]byte, n*allocPerConn)
 	for i := range pool.conns {
-		bufoff := 2 * i * bufsize
+		bufoff := i * allocPerConn
+		txOff := bufoff + cfg.RxBufSize
 		err := pool.conns[i].Configure(tcp.ConnConfig{
-			RxBuf:             bufSpace[bufoff : bufoff+bufsize],
-			TxBuf:             bufSpace[bufoff+bufsize : bufoff+2*bufsize],
+			RxBuf:             bufSpace[bufoff:txOff],
+			TxBuf:             bufSpace[txOff : txOff+cfg.TxBufSize],
 			TxPacketQueueSize: cfg.QueueSize,
 			Logger:            cfg.ConnLogger,
 		})
 		if err != nil {
 			return nil, err
 		}
+		if cfg.NewUserData != nil {
+			pool.userData[i] = cfg.NewUserData()
+		}
 	}
 	return pool, nil
 }
@@ -83,7 +93,7 @@ func (p *TCPPool) NumberOfAcquired() int {
 	return p.naqcuired
 }
 
-func (p *TCPPool) GetTCP() (*tcp.Conn, tcp.Value) {
+func (p *TCPPool) GetTCP() (conn *tcp.Conn, userData any, SuggestedISS tcp.Value) {
 	p.mu.Lock()
 	defer p.mu.Unlock()
 	p.debug("TCPPool:get")
@@ -92,10 +102,10 @@ func (p *TCPPool) GetTCP() (*tcp.Conn, tcp.Value) {
 			p.acquiredAt[i] = p.now()
 			p.nextISS += 1000
 			p.naqcuired++
-			return &p.conns[i], p.nextISS
+			return &p.conns[i], p.userData[i], p.nextISS
 		}
 	}
-	return nil, 0
+	return nil, nil, 0
 }
 
 func (p *TCPPool) PutTCP(conn *tcp.Conn) {
@@ -122,7 +132,8 @@ func (p *TCPPool) CheckTimeouts() {
 	defer p.mu.Unlock()
 	p.debug("TCPPool:checktimeouts", slog.Int("acq", p.naqcuired))
 	for i := range p.conns {
-		st := p.conns[i].State()
+		conn := &p.conns[i]
+		st := conn.State()
 		if st == tcp.StateEstablished {
 			continue
 		}
@@ -134,18 +145,18 @@ func (p *TCPPool) CheckTimeouts() {
 		} else if st.IsPreestablished() && p.since(acq) > p.estbTimeout {
 			// Was acquired and did not reach establishment state so we close.
 			// This is part of a syn-flood defense mechanism.
-			p.conns[i].Close()
+			conn.Close()
 		} else if st.IsClosed() || st.IsClosing() {
 			// p.mu.Lock()
 			if p.closingAt[i].IsZero() {
 				p.closingAt[i] = p.now()
 			} else if p.abortedAt[i].IsZero() && p.since(p.closingAt[i]) > p.closingTimeout {
 				p.abortedAt[i] = p.now()
-				p.conns[i].Abort()
-			} else if p.since(p.abortedAt[i]) > 10*time.Second {
+				conn.Abort()
+			} else if !p.abortedAt[i].IsZero() && p.since(p.abortedAt[i]) > 10*time.Second {
 				println("connection aborted and still not returned to TCPPool")
+				println("source", conn.LocalPort(), "remote", conn.RemotePort(), "state", conn.State().String())
 			}
-			// p.mu.Unlock()
 		}
 	}
 }

x/xnet/xnet_concurrent_test.go

@@ -41,7 +41,8 @@ func TestTCPListener_ConcurrentEcho(t *testing.T) {
 	tcpPool, err := NewTCPPool(TCPPoolConfig{
 		PoolSize:           numClients,
 		QueueSize:          4,
-		BufferSize:         512,
+		TxBufSize:          512,
+		RxBufSize:          512,
 		EstablishedTimeout: 5 * time.Second,
 		ClosingTimeout:     5 * time.Second,
 	})
@@ -198,7 +199,7 @@ func echoServer(ctx context.Context, listener *tcp.Listener) {
 			continue
 		}
 
-		conn, err := listener.TryAccept()
+		conn, _, err := listener.TryAccept()
 		if err != nil || conn == nil {
 			continue
 		}

x/xnet/xnet_listener_test.go

@@ -56,7 +56,8 @@ func TestStackAsyncListener_SingleConnection(t *testing.T) {
 	pool, err := NewTCPPool(TCPPoolConfig{
 		PoolSize:           1,
 		QueueSize:          4,
-		BufferSize:         MTU,
+		TxBufSize:          MTU,
+		RxBufSize:          MTU,
 		EstablishedTimeout: 10e9,
 		ClosingTimeout:     10e9,
 	})
@@ -89,7 +90,7 @@ func TestStackAsyncListener_SingleConnection(t *testing.T) {
 	if listener.NumberOfReadyToAccept() != 1 {
 		t.Fatalf("after handshake: expected 1 ready, got %d", listener.NumberOfReadyToAccept())
 	}
-	svConn, err := listener.TryAccept()
+	svConn, _, err := listener.TryAccept()
 	if err != nil {
 		t.Fatalf("TryAccept: %v", err)
 	}
@@ -142,7 +143,8 @@ func TestStackAsyncListener_MultiSequentialConn(t *testing.T) {
 	pool, err := NewTCPPool(TCPPoolConfig{
 		PoolSize:           poolsize,
 		QueueSize:          4,
-		BufferSize:         bufsize,
+		TxBufSize:          bufsize,
+		RxBufSize:          bufsize,
 		EstablishedTimeout: 10e9,
 		ClosingTimeout:     10e9,
 	})
@@ -198,7 +200,7 @@ func TestStackAsyncListener_MultiSequentialConn(t *testing.T) {
 		if listener.NumberOfReadyToAccept() != 1 {
 			t.Fatalf("after handshake: expected 1 ready, got %d", listener.NumberOfReadyToAccept())
 		}
-		svconn, err := listener.TryAccept()
+		svconn, _, err := listener.TryAccept()
 		if err != nil {
 			t.Fatal(err)
 		} else if svconn.RemotePort() != clConn.LocalPort() ||