feat: hid rpc channel

hidrpc.go

@@ -0,0 +1,150 @@
+package kvm
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/jetkvm/kvm/internal/hidrpc"
+	"github.com/jetkvm/kvm/internal/usbgadget"
+)
+
+func handleHidRpcMessage(message hidrpc.Message, session *Session) {
+	var rpcErr error
+
+	switch message.Type() {
+	case hidrpc.TypeHandshake:
+		message, err := hidrpc.NewHandshakeMessage().Marshal()
+		if err != nil {
+			logger.Warn().Err(err).Msg("failed to marshal handshake message")
+			return
+		}
+		if err := session.HidChannel.Send(message); err != nil {
+			logger.Warn().Err(err).Msg("failed to send handshake message")
+			return
+		}
+		session.hidRpcAvailable = true
+	case hidrpc.TypeKeypressReport, hidrpc.TypeKeyboardReport:
+		keysDownState, err := handleHidRpcKeyboardInput(message)
+		if keysDownState != nil {
+			reportHidRpcKeysDownState(*keysDownState, session)
+		}
+		rpcErr = err
+	case hidrpc.TypePointerReport:
+		pointerReport, err := message.PointerReport()
+		if err != nil {
+			logger.Warn().Err(err).Msg("failed to get pointer report")
+			return
+		}
+		rpcErr = rpcAbsMouseReport(pointerReport.X, pointerReport.Y, pointerReport.Button)
+	case hidrpc.TypeMouseReport:
+		mouseReport, err := message.MouseReport()
+		if err != nil {
+			logger.Warn().Err(err).Msg("failed to get mouse report")
+			return
+		}
+		rpcErr = rpcRelMouseReport(mouseReport.DX, mouseReport.DY, mouseReport.Button)
+	default:
+		logger.Warn().Uint8("type", uint8(message.Type())).Msg("unknown HID RPC message type")
+	}
+
+	if rpcErr != nil {
+		logger.Warn().Err(rpcErr).Msg("failed to handle HID RPC message")
+	}
+}
+
+func onHidMessage(data []byte, session *Session) {
+	scopedLogger := hidRpcLogger.With().Bytes("data", data).Logger()
+	scopedLogger.Debug().Msg("HID RPC message received")
+
+	if len(data) < 1 {
+		scopedLogger.Warn().Int("length", len(data)).Msg("received empty data in HID RPC message handler")
+		return
+	}
+
+	var message hidrpc.Message
+
+	if err := hidrpc.Unmarshal(data, &message); err != nil {
+		scopedLogger.Warn().Err(err).Msg("failed to unmarshal HID RPC message")
+		return
+	}
+
+	scopedLogger = scopedLogger.With().Str("descr", message.String()).Logger()
+
+	t := time.Now()
+
+	r := make(chan interface{})
+	go func() {
+		handleHidRpcMessage(message, session)
+		r <- nil
+	}()
+	select {
+	case <-time.After(1 * time.Second):
+		scopedLogger.Warn().Msg("HID RPC message timed out")
+	case <-r:
+		scopedLogger.Debug().Dur("duration", time.Since(t)).Msg("HID RPC message handled")
+	}
+}
+
+func handleHidRpcKeyboardInput(message hidrpc.Message) (*usbgadget.KeysDownState, error) {
+	switch message.Type() {
+	case hidrpc.TypeKeypressReport:
+		keypressReport, err := message.KeypressReport()
+		if err != nil {
+			logger.Warn().Err(err).Msg("failed to get keypress report")
+			return nil, err
+		}
+		keysDownState, rpcError := rpcKeypressReport(keypressReport.Key, keypressReport.Press)
+		return &keysDownState, rpcError
+	case hidrpc.TypeKeyboardReport:
+		keyboardReport, err := message.KeyboardReport()
+		if err != nil {
+			logger.Warn().Err(err).Msg("failed to get keyboard report")
+			return nil, err
+		}
+		keysDownState, rpcError := rpcKeyboardReport(keyboardReport.Modifier, keyboardReport.Keys)
+		return &keysDownState, rpcError
+	}
+
+	return nil, fmt.Errorf("unknown HID RPC message type: %d", message.Type())
+}
+
+func reportHidRpc(params any, session *Session) {
+	var (
+		message []byte
+		err     error
+	)
+	switch params := params.(type) {
+	case usbgadget.KeyboardState:
+		message, err = hidrpc.NewKeyboardLedMessage(params).Marshal()
+	case usbgadget.KeysDownState:
+		message, err = hidrpc.NewKeydownStateMessage(params).Marshal()
+	}
+
+	if err != nil {
+		logger.Warn().Err(err).Msg("failed to marshal HID RPC message")
+		return
+	}
+
+	if message == nil {
+		logger.Warn().Msg("failed to marshal HID RPC message")
+		return
+	}
+
+	if err := session.HidChannel.Send(message); err != nil {
+		logger.Warn().Err(err).Msg("failed to send HID RPC message")
+	}
+}
+
+func reportHidRpcKeyboardLedState(state usbgadget.KeyboardState, session *Session) {
+	if !session.hidRpcAvailable {
+		writeJSONRPCEvent("keyboardLedState", state, currentSession)
+	}
+	reportHidRpc(state, session)
+}
+
+func reportHidRpcKeysDownState(state usbgadget.KeysDownState, session *Session) {
+	if !session.hidRpcAvailable {
+		writeJSONRPCEvent("keysDownState", state, currentSession)
+	}
+	reportHidRpc(state, session)
+}

internal/hidrpc/hidrpc.go

@@ -0,0 +1,91 @@
+package hidrpc
+
+import (
+	"fmt"
+
+	"github.com/jetkvm/kvm/internal/usbgadget"
+)
+
+// HID RPC is a variable-length packet format that is used to exchange keyboard and mouse events between the client and the server.
+// The packet format is as follows:
+// 1 byte: Event Type
+
+// MessageType is the type of the HID RPC message
+type MessageType uint8
+
+const (
+	TypeHandshake        MessageType = 0x01
+	TypeKeyboardReport   MessageType = 0x02
+	TypePointerReport    MessageType = 0x03
+	TypeWheelReport      MessageType = 0x04
+	TypeKeypressReport   MessageType = 0x05
+	TypeMouseReport      MessageType = 0x06
+	TypeKeyboardLedState MessageType = 0x32
+	TypeKeydownState     MessageType = 0x33
+)
+
+// ShouldUseEnqueue returns true if the message type should be enqueued to the HID queue.
+func ShouldUseEnqueue(messageType MessageType) bool {
+	return messageType == TypeMouseReport
+}
+
+// Unmarshal unmarshals the HID RPC message from the data.
+func Unmarshal(data []byte, message *Message) error {
+	l := len(data)
+	if l < 1 {
+		return fmt.Errorf("invalid data length: %d", l)
+	}
+
+	message.t = MessageType(data[0])
+	message.d = data[1:]
+	return nil
+}
+
+// Marshal marshals the HID RPC message to the data.
+func Marshal(message *Message) ([]byte, error) {
+	if message.t == 0 {
+		return nil, fmt.Errorf("invalid message type: %d", message.t)
+	}
+
+	data := make([]byte, len(message.d)+1)
+	data[0] = byte(message.t)
+	copy(data[1:], message.d)
+
+	return data, nil
+}
+
+// NewHandshakeMessage creates a new handshake message.
+func NewHandshakeMessage() *Message {
+	return &Message{
+		t: TypeHandshake,
+		d: []byte{},
+	}
+}
+
+// NewKeyboardReportMessage creates a new keyboard report message.
+func NewKeyboardReportMessage(keys []byte, modifier uint8) *Message {
+	return &Message{
+		t: TypeKeyboardReport,
+		d: append([]byte{modifier}, keys...),
+	}
+}
+
+// NewKeyboardLedMessage creates a new keyboard LED message.
+func NewKeyboardLedMessage(state usbgadget.KeyboardState) *Message {
+	return &Message{
+		t: TypeKeyboardLedState,
+		d: []byte{state.Byte()},
+	}
+}
+
+// NewKeydownStateMessage creates a new keydown state message.
+func NewKeydownStateMessage(state usbgadget.KeysDownState) *Message {
+	data := make([]byte, len(state.Keys)+1)
+	data[0] = state.Modifier
+	copy(data[1:], state.Keys)
+
+	return &Message{
+		t: TypeKeydownState,
+		d: data,
+	}
+}

internal/hidrpc/message.go

@@ -0,0 +1,121 @@
+package hidrpc
+
+import (
+	"fmt"
+)
+
+// Message ..
+type Message struct {
+	t MessageType
+	d []byte
+}
+
+// Marshal marshals the message to a byte array.
+func (m *Message) Marshal() ([]byte, error) {
+	return Marshal(m)
+}
+
+func (m *Message) Type() MessageType {
+	return m.t
+}
+
+func (m *Message) String() string {
+	switch m.t {
+	case TypeHandshake:
+		return "Handshake"
+	case TypeKeypressReport:
+		return fmt.Sprintf("KeypressReport{Key: %d, Press: %v}", m.d[0], m.d[1] == uint8(1))
+	case TypeKeyboardReport:
+		return fmt.Sprintf("KeyboardReport{Modifier: %d, Keys: %v}", m.d[0], m.d[1:])
+	case TypePointerReport:
+		return fmt.Sprintf("PointerReport{X: %d, Y: %d, Button: %d}", m.d[0:4], m.d[4:8], m.d[8])
+	case TypeMouseReport:
+		return fmt.Sprintf("MouseReport{DX: %d, DY: %d, Button: %d}", m.d[0:2], m.d[2:4], m.d[4])
+	default:
+		return fmt.Sprintf("Unknown{Type: %d, Data: %v}", m.t, m.d)
+	}
+}
+
+// KeypressReport ..
+type KeypressReport struct {
+	Key   byte
+	Press bool
+}
+
+// KeypressReport returns the keypress report from the message.
+func (m *Message) KeypressReport() (KeypressReport, error) {
+	if m.t != TypeKeypressReport {
+		return KeypressReport{}, fmt.Errorf("invalid message type: %d", m.t)
+	}
+
+	return KeypressReport{
+		Key:   m.d[0],
+		Press: m.d[1] == uint8(1),
+	}, nil
+}
+
+// KeyboardReport ..
+type KeyboardReport struct {
+	Modifier byte
+	Keys     []byte
+}
+
+// KeyboardReport returns the keyboard report from the message.
+func (m *Message) KeyboardReport() (KeyboardReport, error) {
+	if m.t != TypeKeyboardReport {
+		return KeyboardReport{}, fmt.Errorf("invalid message type: %d", m.t)
+	}
+
+	return KeyboardReport{
+		Modifier: m.d[0],
+		Keys:     m.d[1:],
+	}, nil
+}
+
+// PointerReport ..
+type PointerReport struct {
+	X      int
+	Y      int
+	Button uint8
+}
+
+func toInt(b []byte) int {
+	return int(b[0])<<24 + int(b[1])<<16 + int(b[2])<<8 + int(b[3])<<0
+}
+
+// PointerReport returns the point report from the message.
+func (m *Message) PointerReport() (PointerReport, error) {
+	if m.t != TypePointerReport {
+		return PointerReport{}, fmt.Errorf("invalid message type: %d", m.t)
+	}
+
+	if len(m.d) != 9 {
+		return PointerReport{}, fmt.Errorf("invalid message length: %d", len(m.d))
+	}
+
+	return PointerReport{
+		X:      toInt(m.d[0:4]),
+		Y:      toInt(m.d[4:8]),
+		Button: uint8(m.d[8]),
+	}, nil
+}
+
+// MouseReport ..
+type MouseReport struct {
+	DX     int8
+	DY     int8
+	Button uint8
+}
+
+// MouseReport returns the mouse report from the message.
+func (m *Message) MouseReport() (MouseReport, error) {
+	if m.t != TypeMouseReport {
+		return MouseReport{}, fmt.Errorf("invalid message type: %d", m.t)
+	}
+
+	return MouseReport{
+		DX:     int8(m.d[0]),
+		DY:     int8(m.d[1]),
+		Button: uint8(m.d[2]),
+	}, nil
+}

internal/usbgadget/consts.go

@@ -1,3 +1,7 @@
 package usbgadget
 
+import "time"
+
 const dwc3Path = "/sys/bus/platform/drivers/dwc3"
+
+const hidWriteTimeout = 10 * time.Millisecond