diff --git a/acknowledge.go b/acknowledge.go
index e264704..fd6ca25 100644
--- a/acknowledge.go
+++ b/acknowledge.go
@@ -97,9 +97,8 @@ func (ack *acknowledgement) read(b []byte) error {
 	if len(b) < 2 {
 		return io.ErrUnexpectedEOF
 	}
-	n := binary.BigEndian.Uint16(b)
 	offset := 2
-	for i := uint16(0); i < n; i++ {
+	for range binary.BigEndian.Uint16(b) {
 		if len(b)-offset < 4 {
 			return io.ErrUnexpectedEOF
 		}
diff --git a/conn.go b/conn.go
index a43322b..82b21d9 100644
--- a/conn.go
+++ b/conn.go
@@ -162,7 +162,6 @@ func (conn *Conn) startTicking() {
 				conn.mu.Lock()
 				acksLeft = len(conn.retransmission.unacknowledged)
 				conn.mu.Unlock()
-
 				if before != 0 && acksLeft == 0 {
 					conn.closeImmediately()
 				}
@@ -383,13 +382,8 @@ func (conn *Conn) send(pk encoding.BinaryMarshaler) error {
 	return err
 }
 
-// packetPool is a sync.Pool used to pool packets that encapsulate their
-// content.
-var packetPool = sync.Pool{
-	New: func() interface{} {
-		return &packet{reliability: reliabilityReliableOrdered}
-	},
-}
+// packetPool is used to pool packets that encapsulate their content.
+var packetPool = sync.Pool{New: func() any { return &packet{reliability: reliabilityReliableOrdered} }}
 
 // receive receives a packet from the connection, handling it as appropriate.
 // If not successful, an error is returned.
@@ -422,13 +416,13 @@ func (conn *Conn) receiveDatagram(b []byte) error {
 	conn.ackSlice = append(conn.ackSlice, seq)
 	conn.ackMu.Unlock()
 
-	if !conn.win.new(seq) {
-		// Datagram was already received, this might happen if a packet took a long time to arrive, and we already sent
-		// a NACK for it. This is expected to happen sometimes under normal circumstances, so no reason to return an
-		// error.
+	if !conn.win.add(seq) {
+		// Datagram was already received, this might happen if a packet took a
+		// long time to arrive, and we already sent a NACK for it. This is
+		// expected to happen sometimes under normal circumstances, so no reason
+		// to return an error.
 		return nil
 	}
-	conn.win.add(seq)
 	if conn.win.shift() == 0 {
 		// Datagram window couldn't be shifted up, so we're still missing
 		// packets.
diff --git a/datagram_window.go b/datagram_window.go
index 4c95b9c..ec1b1c8 100644
--- a/datagram_window.go
+++ b/datagram_window.go
@@ -15,21 +15,23 @@ func newDatagramWindow() *datagramWindow {
 	return &datagramWindow{queue: make(map[uint24]time.Time)}
 }
 
-// new checks if the index passed is new to the datagramWindow.
-func (win *datagramWindow) new(index uint24) bool {
-	if index < win.lowest {
-		return true
+// add puts an index in the window.
+func (win *datagramWindow) add(index uint24) bool {
+	if win.seen(index) {
+		return false
 	}
-	_, ok := win.queue[index]
-	return !ok
+	win.highest = max(win.highest, index+1)
+	win.queue[index] = time.Now()
+	return true
 }
 
-// add puts an index in the window.
-func (win *datagramWindow) add(index uint24) {
-	if index >= win.highest {
-		win.highest = index + 1
+// seen checks if the index passed is known to the datagramWindow.
+func (win *datagramWindow) seen(index uint24) bool {
+	if index < win.lowest {
+		return true
 	}
-	win.queue[index] = time.Now()
+	_, ok := win.queue[index]
+	return ok
 }
 
 // shift attempts to delete as many indices from the queue as possible,
@@ -51,9 +53,7 @@ func (win *datagramWindow) shift() (n int) {
 // set using add while within the window of lowest and highest index. The queue
 // is shifted after this call.
 func (win *datagramWindow) missing(since time.Duration) (indices []uint24) {
-	var (
-		missing = false
-	)
+	missing := false
 	for index := int(win.highest) - 1; index >= int(win.lowest); index-- {
 		i := uint24(index)
 		t, ok := win.queue[i]
diff --git a/dial.go b/dial.go
index 404383e..ea18c9e 100644
--- a/dial.go
+++ b/dial.go
@@ -230,7 +230,7 @@ func (dialer Dialer) DialContext(ctx context.Context, address string) (*Conn, er
 }
 
 func (dialer Dialer) connect(ctx context.Context, state *connState) (*Conn, error) {
-	conn := newConn(internal.ConnToPacketConn(state.conn), state.raddr, state.mtu, &dialerConnectionHandler{})
+	conn := newConn(internal.ConnToPacketConn(state.conn), state.raddr, state.mtu, dialerConnectionHandler{})
 	if err := conn.send((&message.ConnectionRequest{ClientGUID: state.id, RequestTimestamp: timestamp()})); err != nil {
 		return nil, dialer.error("dial", fmt.Errorf("send connection request: %w", err))
 	}
@@ -313,8 +313,7 @@ func (state *connState) discoverMTU(ctx context.Context) error {
 			if err := response.UnmarshalBinary(b[1:n]); err != nil {
 				return fmt.Errorf("read open connection reply 1: %w", err)
 			}
-			state.serverSecurity = response.Secure
-			state.cookie = response.Cookie
+			state.serverSecurity, state.cookie = response.Secure, response.Cookie
 			if response.ServerGUID == 0 || response.ServerPreferredMTUSize < 400 || response.ServerPreferredMTUSize > 1500 {
 				// This is an awful hack we cooked up to deal with OVH 'DDoS'
 				// protection. For some reason they send a broken MTU size
@@ -342,7 +341,7 @@ func (state *connState) request1(ctx context.Context, sizes []uint16) {
 	defer ticker.Stop()
 
 	for _, size := range sizes {
-		for attempt := 0; attempt < 3; attempt++ {
+		for range 3 {
 			state.openConnectionRequest1(size)
 			select {
 			case <-ticker.C:
diff --git a/go.mod b/go.mod
index ea3aa2d..123ea9e 100644
--- a/go.mod
+++ b/go.mod
@@ -1,3 +1,3 @@
 module github.com/sandertv/go-raknet
 
-go 1.21.0
+go 1.22
diff --git a/handler.go b/handler.go
index cdc0658..4500281 100644
--- a/handler.go
+++ b/handler.go
@@ -21,14 +21,22 @@ var (
 	errUnexpectedAdditionalNIC = errors.New("unexpected additional NEW_INCOMING_CONNECTION packet")
 )
 
-func (h *listenerConnectionHandler) handleUnconnected(b []byte, addr net.Addr) error {
+func (h listenerConnectionHandler) limitsEnabled() bool {
+	return true
+}
+
+func (h listenerConnectionHandler) close(conn *Conn) {
+	h.l.connections.Delete(resolve(conn.raddr))
+}
+
+func (h listenerConnectionHandler) handleUnconnected(b []byte, addr net.Addr) error {
 	switch b[0] {
 	case message.IDUnconnectedPing, message.IDUnconnectedPingOpenConnections:
-		return handleUnconnectedPing(h.l, b[1:], addr)
+		return h.handleUnconnectedPing(b[1:], addr)
 	case message.IDOpenConnectionRequest1:
-		return handleOpenConnectionRequest1(h.l, b[1:], addr)
+		return h.handleOpenConnectionRequest1(b[1:], addr)
 	case message.IDOpenConnectionRequest2:
-		return handleOpenConnectionRequest2(h.l, b[1:], addr)
+		return h.handleOpenConnectionRequest2(b[1:], addr)
 	}
 	if b[0]&bitFlagDatagram != 0 {
 		// In some cases, the client will keep trying to send datagrams
@@ -39,14 +47,14 @@ func (h *listenerConnectionHandler) handleUnconnected(b []byte, addr net.Addr) e
 	return fmt.Errorf("unknown packet received (len=%v): %x", len(b), b)
 }
 
-func (h *listenerConnectionHandler) handle(conn *Conn, b []byte) (handled bool, err error) {
+func (h listenerConnectionHandler) handle(conn *Conn, b []byte) (handled bool, err error) {
 	switch b[0] {
 	case message.IDConnectionRequest:
-		return true, handleConnectionRequest(conn, b[1:])
+		return true, h.handleConnectionRequest(conn, b[1:])
 	case message.IDConnectionRequestAccepted:
 		return true, errUnexpectedCRA
 	case message.IDNewIncomingConnection:
-		return true, handleNewIncomingConnection(conn)
+		return true, h.handleNewIncomingConnection(conn)
 	case message.IDConnectedPing:
 		return true, handleConnectedPing(conn, b[1:])
 	case message.IDConnectedPong:
@@ -62,29 +70,21 @@ func (h *listenerConnectionHandler) handle(conn *Conn, b []byte) (handled bool,
 	}
 }
 
-func (h *listenerConnectionHandler) limitsEnabled() bool {
-	return true
-}
-
-func (h *listenerConnectionHandler) close(conn *Conn) {
-	h.l.connections.Delete(resolve(conn.raddr))
-}
-
 // handleUnconnectedPing handles an unconnected ping packet stored in buffer b,
 // coming from an address.
-func handleUnconnectedPing(listener *Listener, b []byte, addr net.Addr) error {
+func (h listenerConnectionHandler) handleUnconnectedPing(b []byte, addr net.Addr) error {
 	pk := &message.UnconnectedPing{}
 	if err := pk.UnmarshalBinary(b); err != nil {
 		return fmt.Errorf("read UNCONNECTED_PING: %w", err)
 	}
-	data, _ := (&message.UnconnectedPong{ServerGUID: listener.id, SendTimestamp: pk.SendTimestamp, Data: *listener.pongData.Load()}).MarshalBinary()
-	_, err := listener.conn.WriteTo(data, addr)
+	data, _ := (&message.UnconnectedPong{ServerGUID: h.l.id, SendTimestamp: pk.SendTimestamp, Data: *h.l.pongData.Load()}).MarshalBinary()
+	_, err := h.l.conn.WriteTo(data, addr)
 	return err
 }
 
 // handleOpenConnectionRequest1 handles an open connection request 1 packet
 // stored in buffer b, coming from an address.
-func handleOpenConnectionRequest1(listener *Listener, b []byte, addr net.Addr) error {
+func (h listenerConnectionHandler) handleOpenConnectionRequest1(b []byte, addr net.Addr) error {
 	pk := &message.OpenConnectionRequest1{}
 	if err := pk.UnmarshalBinary(b); err != nil {
 		return fmt.Errorf("read OPEN_CONNECTION_REQUEST_1: %w", err)
@@ -92,32 +92,32 @@ func handleOpenConnectionRequest1(listener *Listener, b []byte, addr net.Addr) e
 	mtuSize := min(pk.MaximumSizeNotDropped, maxMTUSize)
 
 	if pk.Protocol != protocolVersion {
-		data, _ := (&message.IncompatibleProtocolVersion{ServerGUID: listener.id, ServerProtocol: protocolVersion}).MarshalBinary()
-		_, _ = listener.conn.WriteTo(data, addr)
+		data, _ := (&message.IncompatibleProtocolVersion{ServerGUID: h.l.id, ServerProtocol: protocolVersion}).MarshalBinary()
+		_, _ = h.l.conn.WriteTo(data, addr)
 		return fmt.Errorf("handle OPEN_CONNECTION_REQUEST_1: incompatible protocol version %v (listener protocol = %v)", pk.Protocol, protocolVersion)
 	}
 
-	data, _ := (&message.OpenConnectionReply1{ServerGUID: listener.id, Secure: false, ServerPreferredMTUSize: mtuSize}).MarshalBinary()
-	_, err := listener.conn.WriteTo(data, addr)
+	data, _ := (&message.OpenConnectionReply1{ServerGUID: h.l.id, Secure: false, ServerPreferredMTUSize: mtuSize}).MarshalBinary()
+	_, err := h.l.conn.WriteTo(data, addr)
 	return err
 }
 
 // handleOpenConnectionRequest2 handles an open connection request 2 packet
 // stored in buffer b, coming from an address.
-func handleOpenConnectionRequest2(listener *Listener, b []byte, addr net.Addr) error {
+func (h listenerConnectionHandler) handleOpenConnectionRequest2(b []byte, addr net.Addr) error {
 	pk := &message.OpenConnectionRequest2{}
 	if err := pk.UnmarshalBinary(b); err != nil {
 		return fmt.Errorf("read OPEN_CONNECTION_REQUEST_2: %w", err)
 	}
 	mtuSize := min(pk.ClientPreferredMTUSize, maxMTUSize)
 
-	data, _ := (&message.OpenConnectionReply2{ServerGUID: listener.id, ClientAddress: resolve(addr), MTUSize: mtuSize}).MarshalBinary()
-	if _, err := listener.conn.WriteTo(data, addr); err != nil {
+	data, _ := (&message.OpenConnectionReply2{ServerGUID: h.l.id, ClientAddress: resolve(addr), MTUSize: mtuSize}).MarshalBinary()
+	if _, err := h.l.conn.WriteTo(data, addr); err != nil {
 		return fmt.Errorf("send OPEN_CONNECTION_REPLY_2: %w", err)
 	}
 
-	conn := newConn(listener.conn, addr, mtuSize, listener.h)
-	listener.connections.Store(resolve(addr), conn)
+	conn := newConn(h.l.conn, addr, mtuSize, h)
+	h.l.connections.Store(resolve(addr), conn)
 
 	go func() {
 		t := time.NewTimer(time.Second * 10)
@@ -126,8 +126,8 @@ func handleOpenConnectionRequest2(listener *Listener, b []byte, addr net.Addr) e
 		case <-conn.connected:
 			// Add the connection to the incoming channel so that a caller of
 			// Accept() can receive it.
-			listener.incoming <- conn
-		case <-listener.closed:
+			h.l.incoming <- conn
+		case <-h.l.closed:
 			_ = conn.Close()
 		case <-t.C:
 			// It took too long to complete this connection. We closed it and go
@@ -139,6 +139,28 @@ func handleOpenConnectionRequest2(listener *Listener, b []byte, addr net.Addr) e
 	return nil
 }
 
+// handleConnectionRequest handles a connection request packet inside of buffer
+// b. An error is returned if the packet was invalid.
+func (h listenerConnectionHandler) handleConnectionRequest(conn *Conn, b []byte) error {
+	pk := &message.ConnectionRequest{}
+	if err := pk.UnmarshalBinary(b); err != nil {
+		return fmt.Errorf("read CONNECTION_REQUEST: %w", err)
+	}
+	return conn.send(&message.ConnectionRequestAccepted{ClientAddress: resolve(conn.raddr), RequestTimestamp: pk.RequestTimestamp, AcceptedTimestamp: timestamp()})
+}
+
+// handleNewIncomingConnection handles an incoming connection packet from the
+// client, finalising the Conn.
+func (h listenerConnectionHandler) handleNewIncomingConnection(conn *Conn) error {
+	select {
+	case <-conn.connected:
+		return errUnexpectedAdditionalNIC
+	default:
+		close(conn.connected)
+	}
+	return nil
+}
+
 type dialerConnectionHandler struct{}
 
 var (
@@ -147,12 +169,20 @@ var (
 	errUnexpectedNIC           = errors.New("unexpected NEW_INCOMING_CONNECTION packet")
 )
 
-func (h *dialerConnectionHandler) handle(conn *Conn, b []byte) (handled bool, err error) {
+func (h dialerConnectionHandler) close(conn *Conn) {
+	_ = conn.conn.Close()
+}
+
+func (h dialerConnectionHandler) limitsEnabled() bool {
+	return false
+}
+
+func (h dialerConnectionHandler) handle(conn *Conn, b []byte) (handled bool, err error) {
 	switch b[0] {
 	case message.IDConnectionRequest:
 		return true, errUnexpectedCR
 	case message.IDConnectionRequestAccepted:
-		return true, handleConnectionRequestAccepted(conn, b[1:])
+		return true, h.handleConnectionRequestAccepted(conn, b[1:])
 	case message.IDNewIncomingConnection:
 		return true, errUnexpectedNIC
 	case message.IDConnectedPing:
@@ -170,12 +200,22 @@ func (h *dialerConnectionHandler) handle(conn *Conn, b []byte) (handled bool, er
 	}
 }
 
-func (h *dialerConnectionHandler) close(conn *Conn) {
-	_ = conn.conn.Close()
-}
-
-func (h *dialerConnectionHandler) limitsEnabled() bool {
-	return false
+// handleConnectionRequestAccepted handles a serialised connection request
+// accepted packet in b, and returns an error if not successful.
+func (h dialerConnectionHandler) handleConnectionRequestAccepted(conn *Conn, b []byte) error {
+	pk := &message.ConnectionRequestAccepted{}
+	if err := pk.UnmarshalBinary(b); err != nil {
+		return fmt.Errorf("read CONNECTION_REQUEST_ACCEPTED: %w", err)
+	}
+	select {
+	case <-conn.connected:
+		return errUnexpectedAdditionalCRA
+	default:
+		// Make sure to send NewIncomingConnection before closing conn.connected.
+		err := conn.send(&message.NewIncomingConnection{ServerAddress: resolve(conn.raddr), RequestTimestamp: pk.AcceptedTimestamp, AcceptedTimestamp: timestamp()})
+		close(conn.connected)
+		return err
+	}
 }
 
 // handleConnectedPing handles a connected ping packet inside of buffer b. An
@@ -204,43 +244,3 @@ func handleConnectedPong(b []byte) error {
 	// unreliable and doesn't give a good idea of the connection quality.
 	return nil
 }
-
-// handleConnectionRequest handles a connection request packet inside of buffer
-// b. An error is returned if the packet was invalid.
-func handleConnectionRequest(conn *Conn, b []byte) error {
-	pk := &message.ConnectionRequest{}
-	if err := pk.UnmarshalBinary(b); err != nil {
-		return fmt.Errorf("read CONNECTION_REQUEST: %w", err)
-	}
-	return conn.send(&message.ConnectionRequestAccepted{ClientAddress: resolve(conn.raddr), RequestTimestamp: pk.RequestTimestamp, AcceptedTimestamp: timestamp()})
-}
-
-// handleConnectionRequestAccepted handles a serialised connection request
-// accepted packet in b, and returns an error if not successful.
-func handleConnectionRequestAccepted(conn *Conn, b []byte) error {
-	pk := &message.ConnectionRequestAccepted{}
-	if err := pk.UnmarshalBinary(b); err != nil {
-		return fmt.Errorf("read CONNECTION_REQUEST_ACCEPTED: %w", err)
-	}
-	select {
-	case <-conn.connected:
-		return errUnexpectedAdditionalCRA
-	default:
-		// Make sure to send NewIncomingConnection before closing conn.connected.
-		err := conn.send(&message.NewIncomingConnection{ServerAddress: resolve(conn.raddr), RequestTimestamp: pk.AcceptedTimestamp, AcceptedTimestamp: timestamp()})
-		close(conn.connected)
-		return err
-	}
-}
-
-// handleNewIncomingConnection handles an incoming connection packet from the
-// client, finalising the Conn.
-func handleNewIncomingConnection(conn *Conn) error {
-	select {
-	case <-conn.connected:
-		return errUnexpectedAdditionalNIC
-	default:
-		close(conn.connected)
-	}
-	return nil
-}
diff --git a/internal/message/connection_request_accepted.go b/internal/message/connection_request_accepted.go
index 7b76b63..c7c6c65 100644
--- a/internal/message/connection_request_accepted.go
+++ b/internal/message/connection_request_accepted.go
@@ -20,7 +20,7 @@ func (pk *ConnectionRequestAccepted) UnmarshalBinary(data []byte) error {
 	var offset int
 	pk.ClientAddress, offset = addr(data)
 	offset += 2 // Zero int16.
-	for i := 0; i < 20; i++ {
+	for i := range 20 {
 		if len(data) < addrSize(data[offset:]) {
 			return io.ErrUnexpectedEOF
 		}
diff --git a/internal/message/new_incoming_connection.go b/internal/message/new_incoming_connection.go
index ba1b81f..1a62bce 100644
--- a/internal/message/new_incoming_connection.go
+++ b/internal/message/new_incoming_connection.go
@@ -19,7 +19,7 @@ func (pk *NewIncomingConnection) UnmarshalBinary(data []byte) error {
 	}
 	var offset int
 	pk.ServerAddress, offset = addr(data)
-	for i := 0; i < 20; i++ {
+	for i := range 20 {
 		if len(data) < addrSize(data[offset:]) {
 			return io.ErrUnexpectedEOF
 		}
diff --git a/listener.go b/listener.go
index 80247f9..66fb539 100644
--- a/listener.go
+++ b/listener.go
@@ -30,7 +30,7 @@ type ListenConfig struct {
 // methods as those implemented by the TCPListener in the net package. Listener
 // implements the net.Listener interface.
 type Listener struct {
-	h *listenerConnectionHandler
+	h listenerConnectionHandler
 
 	once   sync.Once
 	closed chan struct{}
@@ -84,7 +84,7 @@ func (l ListenConfig) Listen(address string) (*Listener, error) {
 		log:      l.ErrorLog,
 		id:       atomic.AddInt64(&listenerID, 1),
 	}
-	listener.h = &listenerConnectionHandler{l: listener}
+	listener.h.l = listener
 	if l.ErrorLog == nil {
 		listener.log = slog.Default()
 	}
diff --git a/packet.go b/packet.go
index 42f5f99..250a3e0 100644
--- a/packet.go
+++ b/packet.go
@@ -156,8 +156,9 @@ func (pk *packet) reliable() bool {
 		reliabilityReliableOrdered,
 		reliabilityReliableSequenced:
 		return true
+	default:
+		return false
 	}
-	return false
 }
 
 func (pk *packet) sequencedOrOrdered() bool {
@@ -166,8 +167,9 @@ func (pk *packet) sequencedOrOrdered() bool {
 		reliabilityReliableOrdered,
 		reliabilityReliableSequenced:
 		return true
+	default:
+		return false
 	}
-	return false
 }
 
 func (pk *packet) sequenced() bool {
@@ -175,8 +177,9 @@ func (pk *packet) sequenced() bool {
 	case reliabilityUnreliableSequenced,
 		reliabilityReliableSequenced:
 		return true
+	default:
+		return false
 	}
-	return false
 }
 
 const (
@@ -210,7 +213,7 @@ func split(b []byte, mtu uint16) [][]byte {
 	// to reserve another fragment for the last bit of the packet.
 	fragmentCount := n/maxSize + min(n%maxSize, 1)
 	fragments := make([][]byte, fragmentCount)
-	for i := 0; i < fragmentCount-1; i++ {
+	for i := range fragmentCount - 1 {
 		fragments[i] = b[:maxSize]
 		b = b[maxSize:]
 	}