Merge 12210fac96 into 1717549578

go.mod

@@ -12,6 +12,7 @@ require (
 	github.com/gin-contrib/logger v1.2.6
 	github.com/gin-gonic/gin v1.10.1
 	github.com/go-co-op/gocron/v2 v2.16.5
+	github.com/google/flatbuffers v25.2.10+incompatible
 	github.com/google/uuid v1.6.0
 	github.com/guregu/null/v6 v6.0.0
 	github.com/gwatts/rootcerts v0.0.0-20250901182336-dc5ae18bd79f
@@ -23,6 +24,7 @@ require (
 	github.com/prometheus/common v0.66.0
 	github.com/prometheus/procfs v0.17.0
 	github.com/psanford/httpreadat v0.1.0
+	github.com/rs/xid v1.6.0
 	github.com/rs/zerolog v1.34.0
 	github.com/sourcegraph/tf-dag v0.2.2-0.20250131204052-3e8ff1477b4f
 	github.com/stretchr/testify v1.11.1

go.sum

@@ -53,6 +53,8 @@ github.com/go-playground/validator/v10 v10.26.0/go.mod h1:I5QpIEbmr8On7W0TktmJAu
 github.com/goccy/go-json v0.10.5 h1:Fq85nIqj+gXn/S5ahsiTlK3TmC85qgirsdTP/+DeaC4=
 github.com/goccy/go-json v0.10.5/go.mod h1:oq7eo15ShAhp70Anwd5lgX2pLfOS3QCiwU/PULtXL6M=
 github.com/godbus/dbus/v5 v5.0.4/go.mod h1:xhWf0FNVPg57R7Z0UbKHbJfkEywrmjJnf7w5xrFpKfA=
+github.com/google/flatbuffers v25.2.10+incompatible h1:F3vclr7C3HpB1k9mxCGRMXq6FdUalZ6H/pNX4FP1v0Q=
+github.com/google/flatbuffers v25.2.10+incompatible/go.mod h1:1AeVuKshWv4vARoZatz6mlQ0JxURH0Kv5+zNeJKJCa8=
 github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
 github.com/google/go-cmp v0.7.0/go.mod h1:pXiqmnSA92OHEEa9HXL2W4E7lf9JzCmGVUdgjX3N/iU=
 github.com/google/gofuzz v1.0.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
@@ -152,6 +154,7 @@ github.com/robfig/cron/v3 v3.0.1 h1:WdRxkvbJztn8LMz/QEvLN5sBU+xKpSqwwUO1Pjr4qDs=
 github.com/robfig/cron/v3 v3.0.1/go.mod h1:eQICP3HwyT7UooqI/z+Ov+PtYAWygg1TEWWzGIFLtro=
 github.com/rogpeppe/go-internal v1.14.1 h1:UQB4HGPB6osV0SQTLymcB4TgvyWu6ZyliaW0tI/otEQ=
 github.com/rogpeppe/go-internal v1.14.1/go.mod h1:MaRKkUm5W0goXpeCfT7UZI6fk/L7L7so1lCWt35ZSgc=
+github.com/rs/xid v1.6.0 h1:fV591PaemRlL6JfRxGDEPl69wICngIQ3shQtzfy2gxU=
 github.com/rs/xid v1.6.0/go.mod h1:7XoLgs4eV+QndskICGsho+ADou8ySMSjJKDIan90Nz0=
 github.com/rs/zerolog v1.34.0 h1:k43nTLIwcTVQAncfCw4KZ2VY6ukYoZaBPNOE8txlOeY=
 github.com/rs/zerolog v1.34.0/go.mod h1:bJsvje4Z08ROH4Nhs5iH600c3IkWhwp44iRc54W6wYQ=

hidrpc.go

@@ -6,6 +6,7 @@ import (
 
 	"github.com/jetkvm/kvm/internal/hidrpc"
 	"github.com/jetkvm/kvm/internal/usbgadget"
+	"github.com/rs/zerolog"
 )
 
 func handleHidRPCMessage(message hidrpc.Message, session *Session) {
@@ -29,6 +30,8 @@ func handleHidRPCMessage(message hidrpc.Message, session *Session) {
 			session.reportHidRPCKeysDownState(*keysDownState)
 		}
 		rpcErr = err
+	case hidrpc.TypeKeypressKeepAliveReport:
+		gadget.DelayAutoRelease()
 	case hidrpc.TypePointerReport:
 		pointerReport, err := message.PointerReport()
 		if err != nil {
@@ -52,8 +55,13 @@ func handleHidRPCMessage(message hidrpc.Message, session *Session) {
 	}
 }
 
-func onHidMessage(data []byte, session *Session) {
-	scopedLogger := hidRPCLogger.With().Bytes("data", data).Logger()
+func onHidMessage(msg hidQueueMessage, session *Session) {
+	data := msg.Data
+
+	scopedLogger := hidRPCLogger.With().
+		Str("channel", msg.channel).
+		Bytes("data", data).
+		Logger()
 	scopedLogger.Debug().Msg("HID RPC message received")
 
 	if len(data) < 1 {
@@ -68,7 +76,9 @@ func onHidMessage(data []byte, session *Session) {
 		return
 	}
 
-	scopedLogger = scopedLogger.With().Str("descr", message.String()).Logger()
+	if scopedLogger.GetLevel() <= zerolog.DebugLevel {
+		scopedLogger = scopedLogger.With().Str("descr", message.String()).Logger()
+	}
 
 	t := time.Now()
 
@@ -115,7 +125,10 @@ func reportHidRPC(params any, session *Session) {
 	}
 
 	if !session.hidRPCAvailable || session.HidChannel == nil {
-		logger.Warn().Msg("HID RPC is not available, skipping reportHidRPC")
+		logger.Warn().
+			Bool("hidRPCAvailable", session.hidRPCAvailable).
+			Bool("HidChannel", session.HidChannel != nil).
+			Msg("HID RPC is not available, skipping reportHidRPC")
 		return
 	}
 
@@ -156,7 +169,9 @@ func (s *Session) reportHidRPCKeyboardLedState(state usbgadget.KeyboardState) {
 
 func (s *Session) reportHidRPCKeysDownState(state usbgadget.KeysDownState) {
 	if !s.hidRPCAvailable {
+		usbLogger.Debug().Interface("state", state).Msg("reporting keys down state")
 		writeJSONRPCEvent("keysDownState", state, s)
 	}
+	usbLogger.Debug().Interface("state", state).Msg("reporting keys down state, calling reportHidRPC")
 	reportHidRPC(state, s)
 }

internal/hidrpc/hidrpc.go

@@ -10,14 +10,15 @@ import (
 type MessageType byte
 
 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
+	TypeHandshake               MessageType = 0x01
+	TypeKeyboardReport          MessageType = 0x02
+	TypePointerReport           MessageType = 0x03
+	TypeWheelReport             MessageType = 0x04
+	TypeKeypressReport          MessageType = 0x05
+	TypeKeypressKeepAliveReport MessageType = 0x09
+	TypeMouseReport             MessageType = 0x06
+	TypeKeyboardLedState        MessageType = 0x32
+	TypeKeydownState            MessageType = 0x33
 )
 
 const (
@@ -98,3 +99,11 @@ func NewKeydownStateMessage(state usbgadget.KeysDownState) *Message {
 		d: data,
 	}
 }
+
+// NewKeypressKeepAliveMessage creates a new keypress keep alive message.
+func NewKeypressKeepAliveMessage() *Message {
+	return &Message{
+		t: TypeKeypressKeepAliveReport,
+		d: []byte{},
+	}
+}

internal/hidrpc/message.go

@@ -43,6 +43,8 @@ func (m *Message) String() string {
 			return fmt.Sprintf("MouseReport{Malformed: %v}", m.d)
 		}
 		return fmt.Sprintf("MouseReport{DX: %d, DY: %d, Button: %d}", m.d[0], m.d[1], m.d[2])
+	case TypeKeypressKeepAliveReport:
+		return "KeypressKeepAliveReport"
 	default:
 		return fmt.Sprintf("Unknown{Type: %d, Data: %v}", m.t, m.d)
 	}

internal/usbgadget/hid_keyboard.go

@@ -6,6 +6,9 @@ import (
 	"fmt"
 	"os"
 	"time"
+
+	"github.com/rs/xid"
+	"github.com/rs/zerolog"
 )
 
 var keyboardConfig = gadgetConfigItem{
@@ -22,6 +25,11 @@ var keyboardConfig = gadgetConfigItem{
 	reportDesc: keyboardReportDesc,
 }
 
+// macOS default: 15 * 15 = 225ms https://discussions.apple.com/thread/1316947?sortBy=rank
+// Linux default: 250ms https://man.archlinux.org/man/kbdrate.8.en
+// Windows default: 1ms `HKEY_CURRENT_USER\Control Panel\Accessibility\Keyboard Response\AutoRepeatDelay`
+const autoReleaseKeyboardInterval = time.Millisecond * 100
+
 // Source: https://www.kernel.org/doc/Documentation/usb/gadget_hid.txt
 var keyboardReportDesc = []byte{
 	0x05, 0x01, /* USAGE_PAGE (Generic Desktop)	          */
@@ -173,6 +181,69 @@ func (u *UsbGadget) SetOnKeysDownChange(f func(state KeysDownState)) {
 	u.onKeysDownChange = &f
 }
 
+func (u *UsbGadget) scheduleAutoRelease(key byte) {
+	u.log.Trace().Msg("scheduling autoRelease")
+	u.kbdAutoReleaseLock.Lock()
+	defer unlockWithLog(&u.kbdAutoReleaseLock, u.log, "autoRelease scheduled")
+
+	if u.kbdAutoReleaseTimer != nil {
+		u.kbdAutoReleaseTimer.Stop()
+	}
+
+	u.kbdAutoReleaseTimer = time.AfterFunc(autoReleaseKeyboardInterval, func() {
+		u.performAutoRelease()
+	})
+}
+
+func (u *UsbGadget) cancelAutoRelease() {
+	u.log.Trace().Msg("cancelling autoRelease")
+	u.kbdAutoReleaseLock.Lock()
+	defer unlockWithLog(&u.kbdAutoReleaseLock, u.log, "autoRelease cancelled")
+
+	if u.kbdAutoReleaseTimer != nil {
+		u.kbdAutoReleaseTimer.Stop()
+	}
+}
+
+func (u *UsbGadget) DelayAutoRelease() {
+	u.log.Trace().Msg("delaying autoRelease")
+	u.kbdAutoReleaseLock.Lock()
+	defer unlockWithLog(&u.kbdAutoReleaseLock, u.log, "autoRelease delayed")
+
+	if u.kbdAutoReleaseTimer == nil {
+		return
+	}
+
+	u.kbdAutoReleaseTimer.Reset(autoReleaseKeyboardInterval)
+
+	u.log.Trace().Msg("auto-release timer reset")
+}
+
+func (u *UsbGadget) performAutoRelease() {
+	u.log.Trace().Msg("performing autoRelease")
+	u.kbdAutoReleaseLock.Lock()
+	defer unlockWithLog(&u.kbdAutoReleaseLock, u.log, "autoRelease unlocked")
+
+	key := u.kbdAutoReleaseLastKey
+
+	select {
+	case <-u.keyboardStateCtx.Done():
+		return
+	default:
+	}
+
+	// we just reset the keyboard state to 0 no matter what
+	u.log.Trace().Uint8("key", key).Msg("auto-releasing keyboard key")
+	_, err := u.keypressReport(key, false, false)
+	if err != nil {
+		u.log.Warn().Uint8("key", key).Msg("failed to auto-release keyboard key")
+	}
+
+	u.kbdAutoReleaseTimer = nil
+
+	u.log.Trace().Uint8("key", key).Msg("auto release performed")
+}
+
 func (u *UsbGadget) listenKeyboardEvents() {
 	var path string
 	if u.keyboardHidFile != nil {
@@ -331,17 +402,23 @@ var KeyCodeToMaskMap = map[byte]byte{
 	RightSuper:   ModifierMaskRightSuper,
 }
 
-func (u *UsbGadget) KeypressReport(key byte, press bool) (KeysDownState, error) {
-	u.keyboardLock.Lock()
-	defer u.keyboardLock.Unlock()
+func (u *UsbGadget) keypressReportNonThreadSafe(key byte, press bool, autoRelease bool) (KeysDownState, error) {
 	defer u.resetUserInputTime()
 
+	l := u.log.With().Uint8("key", key).Bool("press", press).Bool("autoRelease", autoRelease).Logger()
+	if l.GetLevel() <= zerolog.DebugLevel {
+		requestID := xid.New()
+		l = l.With().Str("requestID", requestID.String()).Logger()
+	}
+
 	// IMPORTANT: This code parallels the logic in the kernel's hid-gadget driver
 	// for handling key presses and releases. It ensures that the USB gadget
 	// behaves similarly to a real USB HID keyboard. This logic is paralleled
 	// in the client/browser-side code in useKeyboard.ts so make sure to keep
 	// them in sync.
-	var state = u.keysDownState
+	var state = u.GetKeysDownState()
+	l.Trace().Interface("state", state).Msg("got keys down state")
+
 	modifier := state.Modifier
 	keys := append([]byte(nil), state.Keys...)
 
@@ -381,22 +458,76 @@ func (u *UsbGadget) KeypressReport(key byte, press bool) (KeysDownState, error)
 		// If we reach here it means we didn't find an empty slot or the key in the buffer
 		if overrun {
 			if press {
-				u.log.Error().Uint8("key", key).Msg("keyboard buffer overflow, key not added")
+				l.Error().Msg("keyboard buffer overflow, key not added")
 				// Fill all key slots with ErrorRollOver (0x01) to indicate overflow
 				for i := range keys {
 					keys[i] = hidErrorRollOver
 				}
 			} else {
 				// If we are releasing a key, and we didn't find it in a slot, who cares?
-				u.log.Warn().Uint8("key", key).Msg("key not found in buffer, nothing to release")
+				l.Warn().Msg("key not found in buffer, nothing to release")
 			}
 		}
 	}
 
+	if l.GetLevel() <= zerolog.DebugLevel {
+		l = l.With().Uint8("modifier", modifier).Uints8("keys", keys).Logger()
+	}
+
+	l.Trace().Msg("writing keypress report to hidg0")
+
 	err := u.keyboardWriteHidFile(modifier, keys)
 	if err != nil {
-		u.log.Warn().Uint8("modifier", modifier).Uints8("keys", keys).Msg("Could not write keypress report to hidg0")
+		l.Warn().Msg("Could not write keypress report to hidg0")
+	}
+
+	l.Trace().Msg("keypress report written to hidg0")
+
+	if press {
+		{
+			l.Trace().Msg("acquiring kbdAutoReleaseLock to update last key")
+			u.kbdAutoReleaseLock.Lock()
+			u.kbdAutoReleaseLastKey = key
+			unlockWithLog(&u.kbdAutoReleaseLock, u.log, "last key updated")
+		}
+
+		if autoRelease {
+			u.scheduleAutoRelease(key)
+		}
+	} else {
+		if autoRelease {
+			u.cancelAutoRelease()
+		}
 	}
 
 	return u.UpdateKeysDown(modifier, keys), err
 }
+
+type keypressReportResult struct {
+	KeysDownState KeysDownState
+	Error         error
+}
+
+func (u *UsbGadget) keypressReport(key byte, press bool, autoRelease bool) (KeysDownState, error) {
+	u.keyboardLock.Lock()
+	defer u.keyboardLock.Unlock()
+
+	r := make(chan keypressReportResult)
+	go func() {
+		state, err := u.keypressReportNonThreadSafe(key, press, autoRelease)
+		r <- keypressReportResult{KeysDownState: state, Error: err}
+	}()
+
+	select {
+	case <-time.After(1 * time.Second):
+		u.log.Warn().Msg("keypressReport timed out, possibly stuck")
+		return u.keysDownState, fmt.Errorf("keypressReport timed out, possibly stuck")
+	case ret := <-r:
+		u.log.Debug().Msg("keypressReport handled")
+		return ret.KeysDownState, ret.Error
+	}
+}
+
+func (u *UsbGadget) KeypressReport(key byte, press bool) (KeysDownState, error) {
+	return u.keypressReport(key, press, true)
+}

internal/usbgadget/usbgadget.go

@@ -68,6 +68,10 @@ type UsbGadget struct {
 	keyboardState byte          // keyboard latched state (NumLock, CapsLock, ScrollLock, Compose, Kana)
 	keysDownState KeysDownState // keyboard dynamic state (modifier keys and pressed keys)
 
+	kbdAutoReleaseLock    sync.Mutex
+	kbdAutoReleaseTimer   *time.Timer
+	kbdAutoReleaseLastKey byte
+
 	keyboardStateLock   sync.Mutex
 	keyboardStateCtx    context.Context
 	keyboardStateCancel context.CancelFunc
@@ -149,3 +153,35 @@ func newUsbGadget(name string, configMap map[string]gadgetConfigItem, enabledDev
 
 	return g
 }
+
+// Close cleans up resources used by the USB gadget
+func (u *UsbGadget) Close() error {
+	// Cancel keyboard state context
+	if u.keyboardStateCancel != nil {
+		u.keyboardStateCancel()
+	}
+
+	// Stop auto-release timer
+	u.kbdAutoReleaseLock.Lock()
+	if u.kbdAutoReleaseTimer != nil {
+		u.kbdAutoReleaseTimer.Stop()
+		u.kbdAutoReleaseTimer = nil
+	}
+	u.kbdAutoReleaseLock.Unlock()
+
+	// Close HID files
+	if u.keyboardHidFile != nil {
+		u.keyboardHidFile.Close()
+		u.keyboardHidFile = nil
+	}
+	if u.absMouseHidFile != nil {
+		u.absMouseHidFile.Close()
+		u.absMouseHidFile = nil
+	}
+	if u.relMouseHidFile != nil {
+		u.relMouseHidFile.Close()
+		u.relMouseHidFile = nil
+	}
+
+	return nil
+}

internal/usbgadget/utils.go

@@ -9,6 +9,7 @@ import (
 	"path/filepath"
 	"strconv"
 	"strings"
+	"sync"
 	"time"
 
 	"github.com/rs/zerolog"
@@ -120,6 +121,12 @@ func (u *UsbGadget) writeWithTimeout(file *os.File, data []byte) (n int, err err
 		return
 	}
 
+	u.log.Trace().
+		Str("file", file.Name()).
+		Bytes("data", data).
+		Err(err).
+		Msg("write failed")
+
 	if errors.Is(err, os.ErrDeadlineExceeded) {
 		u.logWithSuppression(
 			fmt.Sprintf("writeWithTimeout_%s", file.Name()),
@@ -164,3 +171,8 @@ func (u *UsbGadget) resetLogSuppressionCounter(counterName string) {
 		u.logSuppressionCounter[counterName] = 0
 	}
 }
+
+func unlockWithLog(lock *sync.Mutex, logger *zerolog.Logger, msg string, args ...any) {
+	logger.Trace().Msgf(msg, args...)
+	lock.Unlock()
+}

ui/src/hooks/hidRpc.ts

@@ -6,6 +6,7 @@ export const HID_RPC_MESSAGE_TYPES = {
     PointerReport: 0x03,
     WheelReport: 0x04,
     KeypressReport: 0x05,
+    KeypressKeepAliveReport: 0x09,
     MouseReport: 0x06,
     KeyboardLedState: 0x32,
     KeysDownState: 0x33,
@@ -278,12 +279,23 @@ export class MouseReportMessage extends RpcMessage {
     }
 }
 
+export class KeypressKeepAliveMessage extends RpcMessage {
+    constructor() {
+        super(HID_RPC_MESSAGE_TYPES.KeypressKeepAliveReport);
+    }
+
+    marshal(): Uint8Array {
+        return new Uint8Array([this.messageType]);
+    }
+}
+
 export const messageRegistry = {
     [HID_RPC_MESSAGE_TYPES.Handshake]: HandshakeMessage,
     [HID_RPC_MESSAGE_TYPES.KeysDownState]: KeysDownStateMessage,
     [HID_RPC_MESSAGE_TYPES.KeyboardLedState]: KeyboardLedStateMessage,
     [HID_RPC_MESSAGE_TYPES.KeyboardReport]: KeyboardReportMessage,
     [HID_RPC_MESSAGE_TYPES.KeypressReport]: KeypressReportMessage,
+    [HID_RPC_MESSAGE_TYPES.KeypressKeepAliveReport]: KeypressKeepAliveMessage,
 }
 
 export const unmarshalHidRpcMessage = (data: Uint8Array): RpcMessage | undefined => {

ui/src/hooks/stores.ts

@@ -106,11 +106,17 @@ export interface RTCState {
   rpcDataChannel: RTCDataChannel | null;
 
   rpcHidProtocolVersion: number | null;
-  setRpcHidProtocolVersion: (version: number) => void;
+  setRpcHidProtocolVersion: (version: number | null) => void;
 
   rpcHidChannel: RTCDataChannel | null;
   setRpcHidChannel: (channel: RTCDataChannel) => void;
 
+  rpcHidUnreliableChannel: RTCDataChannel | null;
+  setRpcHidUnreliableChannel: (channel: RTCDataChannel) => void;
+
+  rpcHidUnreliableNonOrderedChannel: RTCDataChannel | null;
+  setRpcHidUnreliableNonOrderedChannel: (channel: RTCDataChannel) => void;
+
   peerConnectionState: RTCPeerConnectionState | null;
   setPeerConnectionState: (state: RTCPeerConnectionState) => void;
 
@@ -158,11 +164,17 @@ export const useRTCStore = create<RTCState>(set => ({
   setRpcDataChannel: (channel: RTCDataChannel) => set({ rpcDataChannel: channel }),
 
   rpcHidProtocolVersion: null,
-  setRpcHidProtocolVersion: (version: number) => set({ rpcHidProtocolVersion: version }),
+  setRpcHidProtocolVersion: (version: number | null) => set({ rpcHidProtocolVersion: version }),
 
   rpcHidChannel: null,
   setRpcHidChannel: (channel: RTCDataChannel) => set({ rpcHidChannel: channel }),
 
+  rpcHidUnreliableChannel: null,
+  setRpcHidUnreliableChannel: (channel: RTCDataChannel) => set({ rpcHidUnreliableChannel: channel }),
+
+  rpcHidUnreliableNonOrderedChannel: null,
+  setRpcHidUnreliableNonOrderedChannel: (channel: RTCDataChannel) => set({ rpcHidUnreliableNonOrderedChannel: channel }),
+
   transceiver: null,
   setTransceiver: (transceiver: RTCRtpTransceiver) => set({ transceiver }),
 

ui/src/hooks/useHidRpc.ts

@@ -6,6 +6,7 @@ import {
   HID_RPC_VERSION,
   HandshakeMessage,
   KeyboardReportMessage,
+  KeypressKeepAliveMessage,
   KeypressReportMessage,
   MouseReportMessage,
   PointerReportMessage,
@@ -13,20 +14,43 @@ import {
   unmarshalHidRpcMessage,
 } from "./hidRpc";
 
+const KEEPALIVE_MESSAGE = new KeypressKeepAliveMessage();
+
+interface sendMessageParams {
+  ignoreHandshakeState?: boolean;
+  useUnreliableChannel?: boolean;
+  requireOrdered?: boolean;
+}
+
 export function useHidRpc(onHidRpcMessage?: (payload: RpcMessage) => void) {
-  const { rpcHidChannel, setRpcHidProtocolVersion, rpcHidProtocolVersion } = useRTCStore();
+  const {
+    rpcHidChannel,
+    rpcHidUnreliableChannel,
+    rpcHidUnreliableNonOrderedChannel,
+    setRpcHidProtocolVersion,
+    rpcHidProtocolVersion,
+  } = useRTCStore();
+
   const rpcHidReady = useMemo(() => {
     return rpcHidChannel?.readyState === "open" && rpcHidProtocolVersion !== null;
   }, [rpcHidChannel, rpcHidProtocolVersion]);
 
+  const rpcHidUnreliableReady = useMemo(() => {
+    return rpcHidUnreliableChannel?.readyState === "open" && rpcHidProtocolVersion !== null;
+  }, [rpcHidUnreliableChannel, rpcHidProtocolVersion]);
+
+  const rpcHidUnreliableNonOrderedReady = useMemo(() => {
+    return rpcHidUnreliableNonOrderedChannel?.readyState === "open" && rpcHidProtocolVersion !== null;
+  }, [rpcHidUnreliableNonOrderedChannel, rpcHidProtocolVersion]);
+
   const rpcHidStatus = useMemo(() => {
     if (!rpcHidChannel) return "N/A";
     if (rpcHidChannel.readyState !== "open") return rpcHidChannel.readyState;
     if (!rpcHidProtocolVersion) return "handshaking";
-    return `ready (v${rpcHidProtocolVersion})`;
-  }, [rpcHidChannel, rpcHidProtocolVersion]);
+    return `ready (v${rpcHidProtocolVersion}${rpcHidUnreliableReady ? "+u" : ""})`;
+  }, [rpcHidChannel, rpcHidUnreliableReady, rpcHidProtocolVersion]);
 
-  const sendMessage = useCallback((message: RpcMessage, ignoreHandshakeState = false) => {
+  const sendMessage = useCallback((message: RpcMessage, { ignoreHandshakeState, useUnreliableChannel, requireOrdered = true }: sendMessageParams = {}) => {
     if (rpcHidChannel?.readyState !== "open") return;
     if (!rpcHidReady && !ignoreHandshakeState) return;
 
@@ -38,8 +62,24 @@ export function useHidRpc(onHidRpcMessage?: (payload: RpcMessage) => void) {
     }
     if (!data) return;
 
+    if (useUnreliableChannel) {
+      if (requireOrdered && rpcHidUnreliableReady) {
+        rpcHidUnreliableChannel?.send(data as unknown as ArrayBuffer);
+      } else if (!requireOrdered && rpcHidUnreliableNonOrderedReady) {
+        rpcHidUnreliableNonOrderedChannel?.send(data as unknown as ArrayBuffer);
+      }
+      return;
+    }
+
     rpcHidChannel?.send(data as unknown as ArrayBuffer);
-  }, [rpcHidChannel, rpcHidReady]);
+  }, [
+    rpcHidChannel,
+    rpcHidUnreliableChannel,
+    rpcHidUnreliableNonOrderedChannel,
+    rpcHidReady,
+    rpcHidUnreliableReady,
+    rpcHidUnreliableNonOrderedReady,
+  ]);
 
   const reportKeyboardEvent = useCallback(
     (keys: number[], modifier: number) => {
@@ -56,7 +96,7 @@ export function useHidRpc(onHidRpcMessage?: (payload: RpcMessage) => void) {
 
   const reportAbsMouseEvent = useCallback(
     (x: number, y: number, buttons: number) => {
-      sendMessage(new PointerReportMessage(x, y, buttons));
+      sendMessage(new PointerReportMessage(x, y, buttons), { useUnreliableChannel: true });
     },
     [sendMessage],
   );
@@ -68,11 +108,15 @@ export function useHidRpc(onHidRpcMessage?: (payload: RpcMessage) => void) {
     [sendMessage],
   );
 
+  const reportKeypressKeepAlive = useCallback(() => {
+    sendMessage(KEEPALIVE_MESSAGE, { useUnreliableChannel: true, requireOrdered: false });
+  }, [sendMessage]);
+
   const sendHandshake = useCallback(() => {
     if (rpcHidProtocolVersion) return;
     if (!rpcHidChannel) return;
 
-    sendMessage(new HandshakeMessage(HID_RPC_VERSION), true);
+    sendMessage(new HandshakeMessage(HID_RPC_VERSION), { ignoreHandshakeState: true });
   }, [rpcHidChannel, rpcHidProtocolVersion, sendMessage]);
 
   const handleHandshake = useCallback((message: HandshakeMessage) => {
@@ -123,10 +167,24 @@ export function useHidRpc(onHidRpcMessage?: (payload: RpcMessage) => void) {
       onHidRpcMessage?.(message);
     };
 
+    const openHandler = () => {
+      console.warn("HID RPC channel opened");
+      sendHandshake();
+    };
+
+    const closeHandler = () => {
+      console.warn("HID RPC channel closed");
+      setRpcHidProtocolVersion(null);
+    };
+
     rpcHidChannel.addEventListener("message", messageHandler);
+    rpcHidChannel.addEventListener("close", closeHandler);
+    rpcHidChannel.addEventListener("open", openHandler);
 
     return () => {
       rpcHidChannel.removeEventListener("message", messageHandler);
+      rpcHidChannel.removeEventListener("close", closeHandler);
+      rpcHidChannel.removeEventListener("open", openHandler);
     };
   },
     [
@@ -143,6 +201,7 @@ export function useHidRpc(onHidRpcMessage?: (payload: RpcMessage) => void) {
     reportKeypressEvent,
     reportAbsMouseEvent,
     reportRelMouseEvent,
+    reportKeypressKeepAlive,
     rpcHidProtocolVersion,
     rpcHidReady,
     rpcHidStatus,

ui/src/hooks/useKeyboard.ts

@@ -1,4 +1,4 @@
-import { useCallback } from "react";
+import { useCallback, useRef } from "react";
 
 import { hidErrorRollOver, hidKeyBufferSize, KeysDownState, useHidStore, useRTCStore } from "@/hooks/stores";
 import { JsonRpcResponse, useJsonRpc } from "@/hooks/useJsonRpc";
@@ -11,6 +11,9 @@ export default function useKeyboard() {
   const { rpcDataChannel } = useRTCStore();
   const { keysDownState, setKeysDownState, setKeyboardLedState } = useHidStore();
 
+  // Keepalive timer management
+  const keepAliveTimerRef = useRef<number | null>(null);
+
   // INTRODUCTION: The earlier version of the JetKVM device shipped with all keyboard state
   // being tracked on the browser/client-side. When adding the keyPressReport API to the
   // device-side code, we have to still support the situation where the browser/client-side code
@@ -26,6 +29,7 @@ export default function useKeyboard() {
   const {
     reportKeyboardEvent: sendKeyboardEventHidRpc,
     reportKeypressEvent: sendKeypressEventHidRpc,
+    reportKeypressKeepAlive: sendKeypressKeepAliveHidRpc,
     rpcHidReady,
   } = useHidRpc((message) => {
     switch (message.constructor) {
@@ -70,17 +74,6 @@ export default function useKeyboard() {
     ],
   );
 
-  // resetKeyboardState is used to reset the keyboard state to no keys pressed and no modifiers.
-  // This is useful for macros and when the browser loses focus to ensure that the keyboard state
-  // is clean.
-  const resetKeyboardState = useCallback(
-    async () => {
-      // Reset the keys buffer to zeros and the modifier state to zero
-      keysDownState.keys.length = hidKeyBufferSize;
-      keysDownState.keys.fill(0);
-      keysDownState.modifier = 0;
-      sendKeyboardEvent(keysDownState);
-    }, [keysDownState, sendKeyboardEvent]);
 
   // executeMacro is used to execute a macro consisting of multiple steps.
   // Each step can have multiple keys, multiple modifiers and a delay.
@@ -111,12 +104,61 @@ export default function useKeyboard() {
     }
   };
 
+  const KEEPALIVE_INTERVAL = 75; // TODO: use an adaptive interval based on RTT later
+
+  const cancelKeepAlive = useCallback(() => {
+    if (keepAliveTimerRef.current) {
+      clearInterval(keepAliveTimerRef.current);
+      keepAliveTimerRef.current = null;
+    }
+  }, []);
+
+  const scheduleKeepAlive = useCallback(() => {
+    // Clear existing timer if it exists
+    if (keepAliveTimerRef.current) {
+      clearInterval(keepAliveTimerRef.current);
+    }
+
+    // Create new interval timer
+    keepAliveTimerRef.current = setInterval(() => {
+      sendKeypressKeepAliveHidRpc();
+    }, KEEPALIVE_INTERVAL);
+  }, [sendKeypressKeepAliveHidRpc]);
+
+  // resetKeyboardState is used to reset the keyboard state to no keys pressed and no modifiers.
+  // This is useful for macros and when the browser loses focus to ensure that the keyboard state
+  // is clean.
+  const resetKeyboardState = useCallback(async () => {
+    // Cancel keepalive since we're resetting the keyboard state
+    cancelKeepAlive();
+
+    // Reset the keys buffer to zeros and the modifier state to zero
+    keysDownState.keys.length = hidKeyBufferSize;
+    keysDownState.keys.fill(0);
+    keysDownState.modifier = 0;
+    sendKeyboardEvent(keysDownState);
+  }, [keysDownState, sendKeyboardEvent, cancelKeepAlive]);
+
   // handleKeyPress is used to handle a key press or release event.
   // This function handle both key press and key release events.
   // It checks if the keyPressReport API is available and sends the key press event.
   // If the keyPressReport API is not available, it simulates the device-side key
   // handling for legacy devices and updates the keysDownState accordingly.
   // It then sends the full keyboard state to the device.
+
+  const sendKeypress = useCallback(
+    (key: number, press: boolean) => {
+      cancelKeepAlive();
+
+      sendKeypressEventHidRpc(key, press);
+
+      if (press) {
+        scheduleKeepAlive();
+      }
+    },
+    [sendKeypressEventHidRpc, scheduleKeepAlive, cancelKeepAlive],
+  );
+
   const handleKeyPress = useCallback(
     async (key: number, press: boolean) => {
       if (rpcDataChannel?.readyState !== "open" && !rpcHidReady) return;
@@ -129,7 +171,7 @@ export default function useKeyboard() {
         // Older device version doesn't support this API, so we will switch to local key handling
         // In that case we will switch to local key handling and update the keysDownState
         // in client/browser-side code using simulateDeviceSideKeyHandlingForLegacyDevices.
-        sendKeypressEventHidRpc(key, press);
+        sendKeypress(key, press);
       } else {
         // if the keyPress api is not available, we need to handle the key locally
         const downState = simulateDeviceSideKeyHandlingForLegacyDevices(keysDownState, key, press);
@@ -147,7 +189,7 @@ export default function useKeyboard() {
       resetKeyboardState,
       rpcDataChannel?.readyState,
       sendKeyboardEvent,
-      sendKeypressEventHidRpc,
+      sendKeypress,
     ],
   );
 
@@ -210,5 +252,10 @@ export default function useKeyboard() {
     return { modifier: modifiers, keys };
   }
 
-  return { handleKeyPress, resetKeyboardState, executeMacro };
+  // Cleanup function to cancel keepalive timer
+  const cleanup = useCallback(() => {
+    cancelKeepAlive();
+  }, [cancelKeepAlive]);
+
+  return { handleKeyPress, resetKeyboardState, executeMacro, cleanup };
 }

ui/src/routes/devices.$id.tsx

@@ -136,6 +136,8 @@ export default function KvmIdRoute() {
     rpcDataChannel,
     setTransceiver,
     setRpcHidChannel,
+    setRpcHidUnreliableNonOrderedChannel,
+    setRpcHidUnreliableChannel,
   } = useRTCStore();
 
   const location = useLocation();
@@ -488,6 +490,24 @@ export default function KvmIdRoute() {
       setRpcHidChannel(rpcHidChannel);
     };
 
+    const rpcHidUnreliableChannel = pc.createDataChannel("hidrpc-unreliable-ordered", {
+      ordered: true,
+      maxRetransmits: 0,
+    });
+    rpcHidUnreliableChannel.binaryType = "arraybuffer";
+    rpcHidUnreliableChannel.onopen = () => {
+      setRpcHidUnreliableChannel(rpcHidUnreliableChannel);
+    };
+
+    const rpcHidUnreliableNonOrderedChannel = pc.createDataChannel("hidrpc-unreliable-nonordered", {
+      ordered: false,
+      maxRetransmits: 0,
+    });
+    rpcHidUnreliableNonOrderedChannel.binaryType = "arraybuffer";
+    rpcHidUnreliableNonOrderedChannel.onopen = () => {
+      setRpcHidUnreliableNonOrderedChannel(rpcHidUnreliableNonOrderedChannel);
+    };
+
     setPeerConnection(pc);
   }, [
     cleanupAndStopReconnecting,
@@ -499,6 +519,8 @@ export default function KvmIdRoute() {
     setPeerConnectionState,
     setRpcDataChannel,
     setRpcHidChannel,
+    setRpcHidUnreliableNonOrderedChannel,
+    setRpcHidUnreliableChannel,
     setTransceiver,
   ]);
 

webrtc.go

@@ -29,7 +29,12 @@ type Session struct {
 
 	hidRPCAvailable bool
 	hidQueueLock    sync.Mutex
-	hidQueue        []chan webrtc.DataChannelMessage
+	hidQueue        []chan hidQueueMessage
+}
+
+type hidQueueMessage struct {
+	webrtc.DataChannelMessage
+	channel string
 }
 
 type SessionConfig struct {
@@ -78,16 +83,59 @@ func (s *Session) initQueues() {
 	s.hidQueueLock.Lock()
 	defer s.hidQueueLock.Unlock()
 
-	s.hidQueue = make([]chan webrtc.DataChannelMessage, 0)
+	s.hidQueue = make([]chan hidQueueMessage, 0)
 	for i := 0; i < 4; i++ {
-		q := make(chan webrtc.DataChannelMessage, 256)
+		q := make(chan hidQueueMessage, 256)
 		s.hidQueue = append(s.hidQueue, q)
 	}
 }
 
 func (s *Session) handleQueues(index int) {
 	for msg := range s.hidQueue[index] {
-		onHidMessage(msg.Data, s)
+		onHidMessage(msg, s)
+	}
+}
+
+func getOnHidMessageHandler(session *Session, scopedLogger *zerolog.Logger, channel string) func(msg webrtc.DataChannelMessage) {
+	return func(msg webrtc.DataChannelMessage) {
+		l := scopedLogger.With().
+			Str("channel", channel).
+			Int("length", len(msg.Data)).
+			Logger()
+		// only log data if the log level is debug or lower
+		if scopedLogger.GetLevel() > zerolog.DebugLevel {
+			l = l.With().Str("data", string(msg.Data)).Logger()
+		}
+
+		if msg.IsString {
+			l.Warn().Msg("received string data in HID RPC message handler")
+			return
+		}
+
+		if len(msg.Data) < 1 {
+			l.Warn().Msg("received empty data in HID RPC message handler")
+			return
+		}
+
+		l.Trace().Msg("received data in HID RPC message handler")
+
+		// Enqueue to ensure ordered processing
+		queueIndex := hidrpc.GetQueueIndex(hidrpc.MessageType(msg.Data[0]))
+		if queueIndex >= len(session.hidQueue) || queueIndex < 0 {
+			l.Warn().Int("queueIndex", queueIndex).Msg("received data in HID RPC message handler, but queue index not found")
+			queueIndex = 3
+		}
+
+		queue := session.hidQueue[queueIndex]
+		if queue != nil {
+			queue <- hidQueueMessage{
+				DataChannelMessage: msg,
+				channel:            channel,
+			}
+		} else {
+			l.Warn().Int("queueIndex", queueIndex).Msg("received data in HID RPC message handler, but queue is nil")
+			return
+		}
 	}
 }
 
@@ -157,40 +205,12 @@ func newSession(config SessionConfig) (*Session, error) {
 		switch d.Label() {
 		case "hidrpc":
 			session.HidChannel = d
-			d.OnMessage(func(msg webrtc.DataChannelMessage) {
-				l := scopedLogger.With().Int("length", len(msg.Data)).Logger()
-				// only log data if the log level is debug or lower
-				if scopedLogger.GetLevel() > zerolog.DebugLevel {
-					l = l.With().Str("data", string(msg.Data)).Logger()
-				}
-
-				if msg.IsString {
-					l.Warn().Msg("received string data in HID RPC message handler")
-					return
-				}
-
-				if len(msg.Data) < 1 {
-					l.Warn().Msg("received empty data in HID RPC message handler")
-					return
-				}
-
-				l.Trace().Msg("received data in HID RPC message handler")
-
-				// Enqueue to ensure ordered processing
-				queueIndex := hidrpc.GetQueueIndex(hidrpc.MessageType(msg.Data[0]))
-				if queueIndex >= len(session.hidQueue) || queueIndex < 0 {
-					l.Warn().Int("queueIndex", queueIndex).Msg("received data in HID RPC message handler, but queue index not found")
-					queueIndex = 3
-				}
-
-				queue := session.hidQueue[queueIndex]
-				if queue != nil {
-					queue <- msg
-				} else {
-					l.Warn().Int("queueIndex", queueIndex).Msg("received data in HID RPC message handler, but queue is nil")
-					return
-				}
-			})
+			d.OnMessage(getOnHidMessageHandler(session, scopedLogger, "hidrpc"))
+		// we won't send anything over the unreliable channels
+		case "hidrpc-unreliable-ordered":
+			d.OnMessage(getOnHidMessageHandler(session, scopedLogger, "hidrpc-unreliable-ordered"))
+		case "hidrpc-unreliable-nonordered":
+			d.OnMessage(getOnHidMessageHandler(session, scopedLogger, "hidrpc-unreliable-nonordered"))
 		case "rpc":
 			session.RPCChannel = d
 			d.OnMessage(func(msg webrtc.DataChannelMessage) {