added isochronous modus

This commit is contained in:
duffyduck 2026-02-18 22:42:52 +01:00
parent 170f5dabcc
commit 99d9242264
7 changed files with 428 additions and 60 deletions

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@ -24,13 +24,29 @@ type Device struct {
// Interface represents a USB interface
type Interface struct {
Number uint8 `json:"number"`
Class uint8 `json:"class"`
SubClass uint8 `json:"sub_class"`
Protocol uint8 `json:"protocol"`
Driver string `json:"driver"`
Number uint8 `json:"number"`
Class uint8 `json:"class"`
SubClass uint8 `json:"sub_class"`
Protocol uint8 `json:"protocol"`
Driver string `json:"driver"`
Endpoints []Endpoint `json:"endpoints"`
}
// Endpoint represents a USB endpoint
type Endpoint struct {
Address uint8 `json:"address"` // bEndpointAddress (bit 7=direction, bits 3:0=number)
TransferType uint8 `json:"transfer_type"` // 0=control, 1=iso, 2=bulk, 3=interrupt
MaxPacketSize uint16 `json:"max_packet_size"`
}
// USB transfer types (from bmAttributes)
const (
TransferTypeControl = 0
TransferTypeIsochronous = 1
TransferTypeBulk = 2
TransferTypeInterrupt = 3
)
// DevID returns the USB/IP device ID (busnum << 16 | devnum)
func (d *Device) DevID() uint32 {
return (d.BusNum << 16) | d.DevNum

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@ -127,12 +127,55 @@ func readInterfaces(sysPath, busID string) []Interface {
iface.Driver = filepath.Base(driverLink)
}
// Read endpoints
iface.Endpoints = readEndpoints(ifacePath)
ifaces = append(ifaces, iface)
}
return ifaces
}
func readEndpoints(ifacePath string) []Endpoint {
entries, err := os.ReadDir(ifacePath)
if err != nil {
return nil
}
var eps []Endpoint
for _, entry := range entries {
name := entry.Name()
if !strings.HasPrefix(name, "ep_") || name == "ep_00" {
continue
}
epPath := filepath.Join(ifacePath, name)
addr, _ := strconv.ParseUint(readString(epPath, "bEndpointAddress"), 16, 8)
var transferType uint8
switch readString(epPath, "type") {
case "Control":
transferType = TransferTypeControl
case "Isoc":
transferType = TransferTypeIsochronous
case "Bulk":
transferType = TransferTypeBulk
case "Interrupt":
transferType = TransferTypeInterrupt
}
maxPkt := readUint32(epPath, "wMaxPacketSize")
eps = append(eps, Endpoint{
Address: uint8(addr),
TransferType: transferType,
MaxPacketSize: uint16(maxPkt),
})
}
return eps
}
func readString(dir, attr string) string {
data, err := os.ReadFile(filepath.Join(dir, attr))
if err != nil {

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@ -348,6 +348,109 @@ func (h *DeviceHandle) DiscardURB(urb *usbdevfsURB) error {
return nil
}
// SubmitISOURBParams holds parameters for async ISO URB submission
type SubmitISOURBParams struct {
Endpoint uint8
Flags uint32
Buffer []byte
NumberOfPackets int32
PacketLengths []uint32 // length of each ISO packet
UserContext uintptr
}
// SubmitISOURB submits an asynchronous isochronous URB.
// Returns the URB pointer and the backing memory slice (must be kept alive until reap).
func (h *DeviceHandle) SubmitISOURB(params *SubmitISOURBParams) (urb *usbdevfsURB, mem []byte, err error) {
urbSize := unsafe.Sizeof(usbdevfsURB{})
isoDescSize := unsafe.Sizeof(usbdevfsISOPacketDesc{})
totalSize := urbSize + uintptr(params.NumberOfPackets)*isoDescSize
mem = make([]byte, totalSize)
urb = (*usbdevfsURB)(unsafe.Pointer(&mem[0]))
var bufPtr uintptr
if len(params.Buffer) > 0 {
bufPtr = uintptr(unsafe.Pointer(&params.Buffer[0]))
}
urb.Type = urbTypeISO
urb.Endpoint = params.Endpoint
urb.Flags = params.Flags
urb.Buffer = bufPtr
urb.BufferLength = int32(len(params.Buffer))
urb.NumberOfPackets = params.NumberOfPackets
urb.UserContext = params.UserContext
// Fill ISO packet descriptors (immediately following the URB in memory)
for i := int32(0); i < params.NumberOfPackets; i++ {
descOffset := urbSize + uintptr(i)*isoDescSize
desc := (*usbdevfsISOPacketDesc)(unsafe.Pointer(&mem[descOffset]))
if i < int32(len(params.PacketLengths)) {
desc.Length = params.PacketLengths[i]
}
}
_, _, errno := unix.Syscall(unix.SYS_IOCTL, uintptr(h.fd), usbdevfsSubmitURB, uintptr(unsafe.Pointer(urb)))
if errno != 0 {
return nil, nil, fmt.Errorf("USBDEVFS_SUBMITURB (ISO): %w", errno)
}
return urb, mem, nil
}
// ISOPacketResult holds the result of one ISO packet after reaping
type ISOPacketResult struct {
Length uint32
ActualLength uint32
Status uint32
}
// ReadISOResults reads the ISO packet results from a reaped ISO URB's backing memory.
func ReadISOResults(mem []byte, numPackets int32) []ISOPacketResult {
urbSize := unsafe.Sizeof(usbdevfsURB{})
isoDescSize := unsafe.Sizeof(usbdevfsISOPacketDesc{})
results := make([]ISOPacketResult, numPackets)
for i := int32(0); i < numPackets; i++ {
offset := urbSize + uintptr(i)*isoDescSize
if int(offset+isoDescSize) > len(mem) {
break
}
desc := (*usbdevfsISOPacketDesc)(unsafe.Pointer(&mem[offset]))
results[i] = ISOPacketResult{
Length: desc.Length,
ActualLength: desc.ActualLength,
Status: desc.Status,
}
}
return results
}
// ReapedURBInfo holds exported fields from a reaped URB needed for response building
type ReapedURBInfo struct {
UserContext uintptr
Status int32
ActualLength int32
StartFrame int32
ErrorCount int32
}
// ReapURBInfo blocks until a URB completes and returns exported info
func (h *DeviceHandle) ReapURBInfo() (*ReapedURBInfo, error) {
var urbPtr uintptr
_, _, errno := unix.Syscall(unix.SYS_IOCTL, uintptr(h.fd), usbdevfsReapURB, uintptr(unsafe.Pointer(&urbPtr)))
if errno != 0 {
return nil, fmt.Errorf("USBDEVFS_REAPURB: %w", errno)
}
urb := (*usbdevfsURB)(unsafe.Pointer(urbPtr))
return &ReapedURBInfo{
UserContext: urb.UserContext,
Status: urb.Status,
ActualLength: urb.ActualLength,
StartFrame: urb.StartFrame,
ErrorCount: urb.ErrorCount,
}, nil
}
// GetFile returns an os.File wrapping the device fd (useful for epoll/select)
func (h *DeviceHandle) GetFile() *os.File {
return os.NewFile(uintptr(h.fd), h.devPath)

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@ -304,6 +304,56 @@ func BuildRetSubmit(seqNum, devID, direction, endpoint uint32, status int32, dat
return buf.Bytes(), nil
}
// BuildRetSubmitISO builds a RET_SUBMIT message for isochronous transfers.
// The transfer data must already be packed (compact, no gaps).
func BuildRetSubmitISO(seqNum, devID, direction, endpoint uint32, status int32,
packedData []byte, startFrame uint32, numPackets int32, errorCount int32,
isoDescs []ISOPacketDescriptor) ([]byte, error) {
buf := &bytes.Buffer{}
hdr := &URBHeader{
Command: RetSubmit,
SeqNum: seqNum,
DevID: devID,
Direction: direction,
Endpoint: endpoint,
}
if err := WriteURBHeader(buf, hdr); err != nil {
return nil, err
}
actualLen := uint32(0)
if direction == DirIn && packedData != nil {
actualLen = uint32(len(packedData))
}
body := &RetSubmitBody{
Status: status,
ActualLength: actualLen,
StartFrame: startFrame,
NumberOfPackets: uint32(numPackets),
ErrorCount: uint32(errorCount),
}
if err := WriteRetSubmit(buf, body); err != nil {
return nil, err
}
// Transfer buffer (packed) for IN direction
if direction == DirIn && len(packedData) > 0 {
buf.Write(packedData)
}
// ISO packet descriptors
for _, desc := range isoDescs {
if err := binary.Write(buf, binary.BigEndian, &desc); err != nil {
return nil, err
}
}
return buf.Bytes(), nil
}
// BuildRetUnlink builds a RET_UNLINK message
func BuildRetUnlink(seqNum, devID uint32, status int32) ([]byte, error) {
buf := &bytes.Buffer{}

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@ -19,20 +19,25 @@ import (
// It manages a single USB device and forwards URBs between
// the USB/IP client (via tunnel) and the physical device (via usbdevfs).
type Server struct {
device *usb.Device
handle *usb.DeviceHandle
mu sync.Mutex
device *usb.Device
handle *usb.DeviceHandle
mu sync.Mutex
pendingURBs map[uint32]*pendingURB // seqnum -> pending URB
closed bool
closed bool
epTypes map[uint8]uint8 // endpoint number (1-15) -> usbdevfs URB type
}
type pendingURB struct {
seqNum uint32
devID uint32
direction uint32
endpoint uint32
buffer []byte
urbPtr unsafe.Pointer // pointer to submitted usbdevfs_urb
seqNum uint32
devID uint32
direction uint32
endpoint uint32
buffer []byte
urbPtr unsafe.Pointer // pointer to submitted usbdevfs_urb
isISO bool
numPackets int32
isoMem []byte // keeps ISO URB+descriptors memory alive for GC
packetLens []uint32 // original request lengths per ISO packet (for offset computation)
}
// NewServer creates a USB/IP server for a specific device
@ -40,6 +45,7 @@ func NewServer(dev *usb.Device) *Server {
return &Server{
device: dev,
pendingURBs: make(map[uint32]*pendingURB),
epTypes: make(map[uint8]uint8),
}
}
@ -51,6 +57,9 @@ func (s *Server) Attach() error {
}
s.handle = handle
// Build endpoint type map from device info (must be done before driver detach)
s.buildEndpointTypeMap()
// For each interface: disconnect kernel driver and claim it
for _, iface := range s.device.Interfaces {
ifnum := uint32(iface.Number)
@ -108,6 +117,43 @@ func (s *Server) Detach() {
s.handle = nil
}
// buildEndpointTypeMap builds the endpoint number -> URB type map from device descriptors
func (s *Server) buildEndpointTypeMap() {
for _, iface := range s.device.Interfaces {
for _, ep := range iface.Endpoints {
epNum := ep.Address & 0x0F
// Map USB descriptor transfer type to usbdevfs URB type
var urbType uint8
switch ep.TransferType {
case usb.TransferTypeControl:
urbType = 2
case usb.TransferTypeIsochronous:
urbType = 0
case usb.TransferTypeBulk:
urbType = 3
case usb.TransferTypeInterrupt:
urbType = 1
default:
urbType = 3 // default bulk
}
s.epTypes[epNum] = urbType
typeNames := map[uint8]string{0: "ISO", 1: "interrupt", 2: "control", 3: "bulk"}
log.Printf("[usbip-server] endpoint %d (0x%02x): %s", epNum, ep.Address, typeNames[urbType])
}
}
}
// getURBType returns the usbdevfs URB type for an endpoint number
func (s *Server) getURBType(endpoint uint8) uint8 {
if endpoint == 0 {
return 2 // control
}
if t, ok := s.epTypes[endpoint]; ok {
return t
}
return 3 // default: bulk
}
// BuildDeviceDescriptor creates a USB/IP device descriptor from our device info
func (s *Server) BuildDeviceDescriptor() DeviceDescriptor {
var desc DeviceDescriptor
@ -211,26 +257,21 @@ func (s *Server) handleCmdSubmit(r io.Reader, hdr *URBHeader, retChan chan<- []b
}
// Read ISO packet descriptors if present
var isoDescs []ISOPacketDescriptor
numPackets := int32(0)
if body.NumberOfPackets != 0xFFFFFFFF && body.NumberOfPackets > 0 {
isoDescs := make([]ISOPacketDescriptor, body.NumberOfPackets)
numPackets = int32(body.NumberOfPackets)
isoDescs = make([]ISOPacketDescriptor, numPackets)
if err := binary.Read(r, binary.BigEndian, &isoDescs); err != nil {
return fmt.Errorf("reading ISO descriptors: %w", err)
}
// TODO: handle ISO transfers properly
}
// Determine URB type from endpoint
endpoint := uint8(hdr.Endpoint)
var urbType uint8
if endpoint == 0 {
urbType = 2 // control
} else {
urbType = 3 // bulk (most common, we'll detect interrupt from endpoint descriptor later)
}
urbType := s.getURBType(endpoint)
// Handle control transfers specially (endpoint 0)
if endpoint == 0 && hdr.Direction == DirIn {
// Control IN: send setup packet, receive data
buf := make([]byte, body.TransferBufferLen)
n, err := s.handle.ControlTransfer(
body.Setup[0], body.Setup[1],
@ -253,7 +294,6 @@ func (s *Server) handleCmdSubmit(r io.Reader, hdr *URBHeader, retChan chan<- []b
}
if endpoint == 0 && hdr.Direction == DirOut {
// Control OUT
buf := transferBuf
if buf == nil {
buf = make([]byte, 0)
@ -277,7 +317,17 @@ func (s *Server) handleCmdSubmit(r io.Reader, hdr *URBHeader, retChan chan<- []b
return nil
}
// For non-control transfers, submit asynchronously
ep := endpoint
if hdr.Direction == DirIn {
ep |= 0x80
}
// Handle isochronous transfers
if urbType == 0 && numPackets > 0 {
return s.handleISOSubmit(hdr, body, transferBuf, isoDescs, numPackets, ep, retChan)
}
// Bulk and interrupt transfers
var buf []byte
if hdr.Direction == DirIn {
buf = make([]byte, body.TransferBufferLen)
@ -285,20 +335,14 @@ func (s *Server) handleCmdSubmit(r io.Reader, hdr *URBHeader, retChan chan<- []b
buf = transferBuf
}
ep := endpoint
if hdr.Direction == DirIn {
ep |= 0x80
}
urb, err := s.handle.SubmitURB(&usb.SubmitURBParams{
Type: urbType,
Endpoint: ep,
Flags: 0,
Buffer: buf,
UserContext: uintptr(hdr.SeqNum),
Type: urbType,
Endpoint: ep,
Flags: 0,
Buffer: buf,
UserContext: uintptr(hdr.SeqNum),
})
if err != nil {
// Submit failed - send error response immediately
resp, _ := BuildRetSubmit(hdr.SeqNum, hdr.DevID, hdr.Direction, hdr.Endpoint, -32, nil)
retChan <- resp
return nil
@ -318,6 +362,73 @@ func (s *Server) handleCmdSubmit(r io.Reader, hdr *URBHeader, retChan chan<- []b
return nil
}
// handleISOSubmit handles isochronous URB submission
func (s *Server) handleISOSubmit(hdr *URBHeader, body *CmdSubmitBody, transferBuf []byte,
isoDescs []ISOPacketDescriptor, numPackets int32, ep uint8, retChan chan<- []byte) error {
// Collect packet lengths and compute total buffer size
packetLens := make([]uint32, numPackets)
var totalBufLen uint32
for i := int32(0); i < numPackets; i++ {
packetLens[i] = isoDescs[i].Length
totalBufLen += isoDescs[i].Length
}
// Prepare buffer
var buf []byte
if hdr.Direction == DirIn {
buf = make([]byte, totalBufLen)
} else {
// For OUT: the incoming data is packed (compact), expand to sequential layout
buf = make([]byte, totalBufLen)
if transferBuf != nil {
srcOff := uint32(0)
dstOff := uint32(0)
for i := int32(0); i < numPackets; i++ {
pktLen := packetLens[i]
if srcOff+pktLen <= uint32(len(transferBuf)) {
copy(buf[dstOff:dstOff+pktLen], transferBuf[srcOff:srcOff+pktLen])
}
srcOff += pktLen
dstOff += pktLen
}
}
}
// Submit ISO URB
urb, isoMem, err := s.handle.SubmitISOURB(&usb.SubmitISOURBParams{
Endpoint: ep,
Flags: 0x02, // URB_ISO_ASAP
Buffer: buf,
NumberOfPackets: numPackets,
PacketLengths: packetLens,
UserContext: uintptr(hdr.SeqNum),
})
if err != nil {
// Submit failed - send error response
resp, _ := BuildRetSubmit(hdr.SeqNum, hdr.DevID, hdr.Direction, hdr.Endpoint, -32, nil)
retChan <- resp
return nil
}
s.mu.Lock()
s.pendingURBs[hdr.SeqNum] = &pendingURB{
seqNum: hdr.SeqNum,
devID: hdr.DevID,
direction: hdr.Direction,
endpoint: hdr.Endpoint,
buffer: buf,
urbPtr: unsafe.Pointer(urb),
isISO: true,
numPackets: numPackets,
isoMem: isoMem,
packetLens: packetLens,
}
s.mu.Unlock()
return nil
}
func (s *Server) handleCmdUnlink(r io.Reader, hdr *URBHeader, retChan chan<- []byte) error {
body, err := ReadCmdUnlink(r)
if err != nil {
@ -333,13 +444,10 @@ func (s *Server) handleCmdUnlink(r io.Reader, hdr *URBHeader, retChan chan<- []b
var status int32
if exists && pending.urbPtr != nil {
// Try to discard the URB
// Note: we cast back to the URB type for the ioctl
urbForDiscard := (*usbDevfsURBForDiscard)(pending.urbPtr)
// Try to discard the URB via proper ioctl
_, _, errno := unix.Syscall(unix.SYS_IOCTL, uintptr(s.handle.Fd()),
uintptr(0x8000550B), // USBDEVFS_DISCARDURB
uintptr(pending.urbPtr))
_ = urbForDiscard
if errno == 0 {
status = -104 // -ECONNRESET
}
@ -354,9 +462,6 @@ func (s *Server) handleCmdUnlink(r io.Reader, hdr *URBHeader, retChan chan<- []b
return nil
}
// usbDevfsURBForDiscard is a placeholder to make the Go compiler happy
type usbDevfsURBForDiscard struct{}
// reapLoop continuously reaps completed URBs and sends responses
func (s *Server) reapLoop(retChan chan<- []byte, done <-chan struct{}) {
for {
@ -373,9 +478,8 @@ func (s *Server) reapLoop(retChan chan<- []byte, done <-chan struct{}) {
}
s.mu.Unlock()
urb, err := s.handle.ReapURB()
urbInfo, err := s.handle.ReapURBInfo()
if err != nil {
// Check if we should stop
select {
case <-done:
return
@ -384,7 +488,7 @@ func (s *Server) reapLoop(retChan chan<- []byte, done <-chan struct{}) {
}
}
seqNum := uint32(urb.UserContext)
seqNum := uint32(urbInfo.UserContext)
s.mu.Lock()
pending, exists := s.pendingURBs[seqNum]
@ -397,19 +501,23 @@ func (s *Server) reapLoop(retChan chan<- []byte, done <-chan struct{}) {
continue
}
var data []byte
if pending.direction == DirIn && urb.ActualLength > 0 {
data = pending.buffer[:urb.ActualLength]
var resp []byte
if pending.isISO {
resp, err = s.buildISOResponse(urbInfo, pending)
} else {
var data []byte
if pending.direction == DirIn && urbInfo.ActualLength > 0 {
data = pending.buffer[:urbInfo.ActualLength]
}
resp, err = BuildRetSubmit(
pending.seqNum,
pending.devID,
pending.direction,
pending.endpoint,
urbInfo.Status,
data,
)
}
resp, err := BuildRetSubmit(
pending.seqNum,
pending.devID,
pending.direction,
pending.endpoint,
urb.Status,
data,
)
if err != nil {
continue
}
@ -422,6 +530,54 @@ func (s *Server) reapLoop(retChan chan<- []byte, done <-chan struct{}) {
}
}
// buildISOResponse builds a RET_SUBMIT for a completed ISO URB
func (s *Server) buildISOResponse(urbInfo *usb.ReapedURBInfo, pending *pendingURB) ([]byte, error) {
// Read ISO packet results from the URB memory
isoResults := usb.ReadISOResults(pending.isoMem, pending.numPackets)
// Build USB/IP ISO descriptors and pack transfer data
var usbipDescs []ISOPacketDescriptor
var packedData []byte
bufOffset := uint32(0) // offset in our sequential buffer
for i := int32(0); i < pending.numPackets; i++ {
pktLen := pending.packetLens[i]
actualLen := isoResults[i].ActualLength
status := isoResults[i].Status
usbipDescs = append(usbipDescs, ISOPacketDescriptor{
Offset: bufOffset,
Length: pktLen,
ActualLength: actualLen,
Status: status,
})
// Pack actual data (compact, no gaps) for IN direction
if pending.direction == DirIn && actualLen > 0 {
end := bufOffset + actualLen
if end > uint32(len(pending.buffer)) {
end = uint32(len(pending.buffer))
}
packedData = append(packedData, pending.buffer[bufOffset:end]...)
}
bufOffset += pktLen
}
return BuildRetSubmitISO(
pending.seqNum,
pending.devID,
pending.direction,
pending.endpoint,
urbInfo.Status,
packedData,
uint32(urbInfo.StartFrame),
pending.numPackets,
urbInfo.ErrorCount,
usbipDescs,
)
}
// HandleDevlistRequest handles an OP_REQ_DEVLIST for this device
func (s *Server) HandleDevlistRequest() ([]byte, error) {
desc := s.BuildDeviceDescriptor()