kvm/usb.go

589 lines
16 KiB
Go

package kvm
import (
"bytes"
"errors"
"fmt"
"log"
"os"
"os/exec"
"path"
"path/filepath"
"strings"
"sync"
"time"
gadget "github.com/openstadia/go-usb-gadget"
)
const configFSPath = "/sys/kernel/config"
const gadgetPath = "/sys/kernel/config/usb_gadget"
const kvmGadgetPath = "/sys/kernel/config/usb_gadget/jetkvm"
const configC1Path = "/sys/kernel/config/usb_gadget/jetkvm/configs/c.1"
func (u *UsbDevicesConfig) isGadgetConfigItemEnabled(itemKey string) bool {
switch itemKey {
case "absolute_mouse":
return u.AbsoluteMouse
case "relative_mouse":
return u.RelativeMouse
case "keyboard":
return u.Keyboard
case "mass_storage_base":
return u.MassStorage
case "mass_storage_usb0":
return u.MassStorage
default:
return true
}
}
type gadgetConfigItem struct {
device string
path []string
attrs gadgetAttributes
configAttrs gadgetAttributes
configPath string
reportDesc []byte
}
type gadgetAttributes map[string]string
var gadgetConfig = map[string]gadgetConfigItem{
"base": {
attrs: gadgetAttributes{
"bcdUSB": "0x0200", // USB 2.0
"idVendor": "0x1d6b", // The Linux Foundation
"idProduct": "0104", // Multifunction Composite Gadget¬
"bcdDevice": "0100",
},
configAttrs: gadgetAttributes{
"MaxPower": "250", // in unit of 2mA
},
},
"base_info": {
path: []string{"strings", "0x409"},
attrs: gadgetAttributes{
"serialnumber": GetDeviceID(),
"manufacturer": "JetKVM",
"product": "JetKVM USB Emulation Device",
},
configAttrs: gadgetAttributes{
"configuration": "Config 1: HID",
},
},
// keyboard HID
"keyboard": {
device: "hid.usb0",
path: []string{"functions", "hid.usb0"},
configPath: path.Join(configC1Path, "hid.usb0"),
attrs: gadgetAttributes{
"protocol": "1",
"subclass": "1",
"report_length": "8",
},
reportDesc: KeyboardReportDesc,
},
// mouse HID
"absolute_mouse": {
device: "hid.usb1",
path: []string{"functions", "hid.usb1"},
configPath: path.Join(configC1Path, "hid.usb1"),
attrs: gadgetAttributes{
"protocol": "2",
"subclass": "1",
"report_length": "6",
},
reportDesc: CombinedAbsoluteMouseReportDesc,
},
// relative mouse HID
"relative_mouse": {
device: "hid.usb2",
path: []string{"functions", "hid.usb2"},
configPath: path.Join(configC1Path, "hid.usb2"),
attrs: gadgetAttributes{
"protocol": "2",
"subclass": "1",
"report_length": "4",
},
reportDesc: CombinedRelativeMouseReportDesc,
},
// mass storage
"mass_storage_base": {
device: "mass_storage.usb0",
path: []string{"functions", "mass_storage.usb0"},
configPath: path.Join(configC1Path, "mass_storage.usb0"),
attrs: gadgetAttributes{
"stall": "1",
},
},
"mass_storage_usb0": {
path: []string{"functions", "mass_storage.usb0", "lun.0"},
attrs: gadgetAttributes{
"cdrom": "1",
"ro": "1",
"removable": "1",
"file": "\n",
"inquiry_string": "JetKVM Virtual Media",
},
},
}
func mountConfigFS() error {
_, err := os.Stat(gadgetPath)
if os.IsNotExist(err) {
err = exec.Command("mount", "-t", "configfs", "none", configFSPath).Run()
if err != nil {
return fmt.Errorf("failed to mount configfs: %w", err)
}
} else {
return fmt.Errorf("unable to access usb gadget path: %w", err)
}
return nil
}
func writeIfDifferent(filePath string, content []byte, permMode os.FileMode) error {
if _, err := os.Stat(filePath); err == nil {
oldContent, err := os.ReadFile(filePath)
if err == nil {
if bytes.Equal(oldContent, content) {
logger.Tracef("skipping writing to %s as it already has the correct content", filePath)
return nil
}
if len(oldContent) == len(content)+1 &&
bytes.Equal(oldContent[:len(content)], content) &&
oldContent[len(content)] == 10 {
logger.Tracef("skipping writing to %s as it already has the correct content", filePath)
return nil
}
logger.Tracef("writing to %s as it has different content %v %v", filePath, oldContent, content)
}
}
return os.WriteFile(filePath, content, permMode)
}
func disableGadgetItemConfig(item gadgetConfigItem) error {
// remove symlink if exists
if item.configPath != "" {
if _, err := os.Lstat(item.configPath); os.IsNotExist(err) {
logger.Tracef("symlink %s does not exist", item.configPath)
} else {
err := os.Remove(item.configPath)
if err != nil {
return fmt.Errorf("failed to remove symlink %s: %w", item.configPath, err)
}
}
}
return nil
}
func writeGadgetItemConfig(item gadgetConfigItem) error {
// create directory for the item
gadgetItemPathArr := append([]string{kvmGadgetPath}, item.path...)
gadgetItemPath := filepath.Join(gadgetItemPathArr...)
err := os.MkdirAll(gadgetItemPath, 0755)
if err != nil {
return fmt.Errorf("failed to create path %s: %w", gadgetItemPath, err)
}
if len(item.configAttrs) > 0 {
configItemPathArr := append([]string{configC1Path}, item.path...)
configItemPath := filepath.Join(configItemPathArr...)
err = os.MkdirAll(configItemPath, 0755)
if err != nil {
return fmt.Errorf("failed to create path %s: %w", config, err)
}
err = writeGadgetAttrs(configItemPath, item.configAttrs)
if err != nil {
return fmt.Errorf("failed to write config attributes for %s: %w", configItemPath, err)
}
}
if len(item.attrs) > 0 {
// write attributes for the item
err = writeGadgetAttrs(gadgetItemPath, item.attrs)
if err != nil {
return fmt.Errorf("failed to write attributes for %s: %w", gadgetItemPath, err)
}
}
// write report descriptor if available
if item.reportDesc != nil {
err = writeIfDifferent(path.Join(gadgetItemPath, "report_desc"), item.reportDesc, 0644)
if err != nil {
return err
}
}
// create symlink if configPath is set
if item.configPath != "" {
logger.Tracef("Creating symlink from %s to %s", item.configPath, gadgetItemPath)
// check if the symlink already exists, if yes, check if it points to the correct path
if _, err := os.Lstat(item.configPath); err == nil {
linkPath, err := os.Readlink(item.configPath)
if err != nil || linkPath != gadgetItemPath {
err = os.Remove(item.configPath)
if err != nil {
return fmt.Errorf("failed to remove existing symlink %s: %w", item.configPath, err)
}
}
} else if !os.IsNotExist(err) {
return fmt.Errorf("failed to check if symlink exists: %w", err)
}
err = os.Symlink(gadgetItemPath, item.configPath)
if err != nil {
return fmt.Errorf("failed to create symlink from %s to %s: %w", item.configPath, gadgetItemPath, err)
}
}
return nil
}
func init() {
ensureConfigLoaded()
_ = os.MkdirAll(imagesFolder, 0755)
udcs := gadget.GetUdcs()
if len(udcs) < 1 {
usbLogger.Error("no udc found, skipping USB stack init")
return
}
udc = udcs[0]
_, err := os.Stat(kvmGadgetPath)
if err == nil {
logger.Info("usb gadget already exists, skipping usb gadget initialization")
return
}
err = mountConfigFS()
if err != nil {
logger.Errorf("failed to mount configfs: %v, usb stack might not function properly", err)
}
err = writeGadgetConfig()
if err != nil {
logger.Errorf("failed to start gadget: %v", err)
}
//TODO: read hid reports(capslock, numlock, etc) from keyboardHidFile
}
func UpdateGadgetConfig() error {
LoadConfig()
gadgetAttrs := [][]string{
{"idVendor", config.UsbConfig.VendorId},
{"idProduct", config.UsbConfig.ProductId},
}
err := writeGadgetAttrs(kvmGadgetPath, gadgetAttrs)
if err != nil {
return err
}
log.Printf("Successfully updated usb gadget attributes: %v", gadgetAttrs)
strAttrs := [][]string{
{"serialnumber", config.UsbConfig.SerialNumber},
{"manufacturer", config.UsbConfig.Manufacturer},
{"product", config.UsbConfig.Product},
}
gadgetStringsPath := filepath.Join(kvmGadgetPath, "strings", "0x409")
err = os.MkdirAll(gadgetStringsPath, 0755)
if err != nil {
return err
}
err = writeGadgetAttrs(gadgetStringsPath, strAttrs)
if err != nil {
return err
}
log.Printf("Successfully updated usb string attributes: %s", strAttrs)
err = rebindUsb()
if err != nil {
return err
}
return nil
}
func writeGadgetAttrs(basePath string, attrs [][]string) error {
for _, item := range attrs {
filePath := filepath.Join(basePath, item[0])
err := os.WriteFile(filePath, []byte(item[1]), 0644)
if err != nil {
return fmt.Errorf("failed to write to %s: %w", filePath, err)
}
}
return nil
}
func writeGadgetConfig() error {
if _, err := os.Stat(gadgetPath); os.IsNotExist(err) {
return fmt.Errorf("USB gadget path does not exist: %s", gadgetPath)
}
err := os.MkdirAll(kvmGadgetPath, 0755)
if err != nil {
return err
}
logger.Tracef("writing gadget config")
for key, item := range gadgetConfig {
// check if the item is enabled in the config
if !config.UsbDevices.isGadgetConfigItemEnabled(key) {
logger.Tracef("disabling gadget config: %s", key)
err = disableGadgetItemConfig(item)
if err != nil {
return err
}
continue
}
logger.Tracef("writing gadget config: %s", key)
err = writeGadgetItemConfig(item)
if err != nil {
return err
}
}
err = os.WriteFile(path.Join(kvmGadgetPath, "UDC"), []byte(udc), 0644)
if err != nil {
return err
}
return nil
}
func rebindUsb() error {
err := os.WriteFile("/sys/bus/platform/drivers/dwc3/unbind", []byte(udc), 0644)
if err != nil {
return err
}
err = os.WriteFile("/sys/bus/platform/drivers/dwc3/bind", []byte(udc), 0644)
if err != nil {
return err
}
return nil
}
var keyboardHidFile *os.File
var keyboardLock = sync.Mutex{}
var mouseHidFile *os.File
var mouseLock = sync.Mutex{}
func rpcKeyboardReport(modifier uint8, keys []uint8) error {
keyboardLock.Lock()
defer keyboardLock.Unlock()
if keyboardHidFile == nil {
var err error
keyboardHidFile, err = os.OpenFile("/dev/hidg0", os.O_RDWR, 0666)
if err != nil {
return fmt.Errorf("failed to open hidg0: %w", err)
}
}
if len(keys) > 6 {
keys = keys[:6]
}
if len(keys) < 6 {
keys = append(keys, make([]uint8, 6-len(keys))...)
}
_, err := keyboardHidFile.Write([]byte{modifier, 0, keys[0], keys[1], keys[2], keys[3], keys[4], keys[5]})
if err != nil {
keyboardHidFile.Close()
keyboardHidFile = nil
return err
}
resetUserInputTime()
return err
}
func rpcAbsMouseReport(x, y int, buttons uint8) error {
mouseLock.Lock()
defer mouseLock.Unlock()
if mouseHidFile == nil {
var err error
mouseHidFile, err = os.OpenFile("/dev/hidg1", os.O_RDWR, 0666)
if err != nil {
return fmt.Errorf("failed to open hidg1: %w", err)
}
}
resetUserInputTime()
_, err := mouseHidFile.Write([]byte{
1, // Report ID 1
buttons, // Buttons
uint8(x), // X Low Byte
uint8(x >> 8), // X High Byte
uint8(y), // Y Low Byte
uint8(y >> 8), // Y High Byte
})
if err != nil {
mouseHidFile.Close()
mouseHidFile = nil
return err
}
return nil
}
var accumulatedWheelY float64 = 0
func rpcWheelReport(wheelY int8) error {
if mouseHidFile == nil {
return errors.New("hid not initialized")
}
// Accumulate the wheelY value with finer granularity
// Reduce divisor from 8.0 to a smaller value (e.g., 2.0 or 4.0)
accumulatedWheelY += float64(wheelY) / 4.0
// Lower the threshold for sending a report (0.25 instead of 1.0)
if abs(accumulatedWheelY) >= 0.25 {
// Scale the wheel value appropriately for the HID report
// The descriptor uses an 8-bit signed value (-127 to 127)
scaledWheelY := int8(accumulatedWheelY * 0.5) // Scale down to prevent too much scrolling
_, err := mouseHidFile.Write([]byte{
2, // Report ID 2
byte(scaledWheelY), // Scaled Wheel Y (signed)
})
// Reset the accumulator, keeping any remainder
accumulatedWheelY -= float64(scaledWheelY) / 0.5 // Adjust based on the scaling factor
resetUserInputTime()
return err
}
return nil
}
// Helper function to get absolute value of float64
func abs(x float64) float64 {
if x < 0 {
return -x
}
return x
}
var usbState = "unknown"
func rpcGetUSBState() (state string) {
stateBytes, err := os.ReadFile("/sys/class/udc/ffb00000.usb/state")
if err != nil {
return "unknown"
}
return strings.TrimSpace(string(stateBytes))
}
func triggerUSBStateUpdate() {
go func() {
if currentSession == nil {
log.Println("No active RPC session, skipping update state update")
return
}
writeJSONRPCEvent("usbState", usbState, currentSession)
}()
}
var udc string
func init() {
ensureConfigLoaded()
go func() {
for {
newState := rpcGetUSBState()
if newState != usbState {
log.Printf("USB state changed from %s to %s", usbState, newState)
usbState = newState
requestDisplayUpdate()
triggerUSBStateUpdate()
}
time.Sleep(500 * time.Millisecond)
}
}()
}
// Source: https://www.kernel.org/doc/Documentation/usb/gadget_hid.txt
var KeyboardReportDesc = []byte{
0x05, 0x01, /* USAGE_PAGE (Generic Desktop) */
0x09, 0x06, /* USAGE (Keyboard) */
0xa1, 0x01, /* COLLECTION (Application) */
0x05, 0x07, /* USAGE_PAGE (Keyboard) */
0x19, 0xe0, /* USAGE_MINIMUM (Keyboard LeftControl) */
0x29, 0xe7, /* USAGE_MAXIMUM (Keyboard Right GUI) */
0x15, 0x00, /* LOGICAL_MINIMUM (0) */
0x25, 0x01, /* LOGICAL_MAXIMUM (1) */
0x75, 0x01, /* REPORT_SIZE (1) */
0x95, 0x08, /* REPORT_COUNT (8) */
0x81, 0x02, /* INPUT (Data,Var,Abs) */
0x95, 0x01, /* REPORT_COUNT (1) */
0x75, 0x08, /* REPORT_SIZE (8) */
0x81, 0x03, /* INPUT (Cnst,Var,Abs) */
0x95, 0x05, /* REPORT_COUNT (5) */
0x75, 0x01, /* REPORT_SIZE (1) */
0x05, 0x08, /* USAGE_PAGE (LEDs) */
0x19, 0x01, /* USAGE_MINIMUM (Num Lock) */
0x29, 0x05, /* USAGE_MAXIMUM (Kana) */
0x91, 0x02, /* OUTPUT (Data,Var,Abs) */
0x95, 0x01, /* REPORT_COUNT (1) */
0x75, 0x03, /* REPORT_SIZE (3) */
0x91, 0x03, /* OUTPUT (Cnst,Var,Abs) */
0x95, 0x06, /* REPORT_COUNT (6) */
0x75, 0x08, /* REPORT_SIZE (8) */
0x15, 0x00, /* LOGICAL_MINIMUM (0) */
0x25, 0x65, /* LOGICAL_MAXIMUM (101) */
0x05, 0x07, /* USAGE_PAGE (Keyboard) */
0x19, 0x00, /* USAGE_MINIMUM (Reserved) */
0x29, 0x65, /* USAGE_MAXIMUM (Keyboard Application) */
0x81, 0x00, /* INPUT (Data,Ary,Abs) */
0xc0, /* END_COLLECTION */
}
// Combined absolute and relative mouse report descriptor with report ID
var CombinedMouseReportDesc = []byte{
0x05, 0x01, // Usage Page (Generic Desktop Ctrls)
0x09, 0x02, // Usage (Mouse)
0xA1, 0x01, // Collection (Application)
// Report ID 1: Absolute Mouse Movement
0x85, 0x01, // Report ID (1)
0x09, 0x01, // Usage (Pointer)
0xA1, 0x00, // Collection (Physical)
0x05, 0x09, // Usage Page (Button)
0x19, 0x01, // Usage Minimum (0x01)
0x29, 0x03, // Usage Maximum (0x03)
0x15, 0x00, // Logical Minimum (0)
0x25, 0x01, // Logical Maximum (1)
0x75, 0x01, // Report Size (1)
0x95, 0x03, // Report Count (3)
0x81, 0x02, // Input (Data, Var, Abs)
0x95, 0x01, // Report Count (1)
0x75, 0x05, // Report Size (5)
0x81, 0x03, // Input (Cnst, Var, Abs)
0x05, 0x01, // Usage Page (Generic Desktop Ctrls)
0x09, 0x30, // Usage (X)
0x09, 0x31, // Usage (Y)
0x16, 0x00, 0x00, // Logical Minimum (0)
0x26, 0xFF, 0x7F, // Logical Maximum (32767)
0x36, 0x00, 0x00, // Physical Minimum (0)
0x46, 0xFF, 0x7F, // Physical Maximum (32767)
0x75, 0x10, // Report Size (16)
0x95, 0x02, // Report Count (2)
0x81, 0x02, // Input (Data, Var, Abs)
0xC0, // End Collection
// Report ID 2: Relative Wheel Movement
0x85, 0x02, // Report ID (2)
0x09, 0x38, // Usage (Wheel)
0x15, 0x81, // Logical Minimum (-127)
0x25, 0x7F, // Logical Maximum (127)
0x75, 0x08, // Report Size (8)
0x95, 0x01, // Report Count (1)
0x81, 0x06, // Input (Data, Var, Rel)
0xC0, // End Collection
}