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Add unknown interface descriptors to Extra #127

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bb19350
Add unknown interface descriptors to Extra
juaoose May 15, 2024
965a497
Update after comments
juaoose May 17, 2024
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19 changes: 10 additions & 9 deletions constants.go
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Original file line number Diff line number Diff line change
Expand Up @@ -94,15 +94,16 @@ type DescriptorType uint8

// Descriptor types defined by the USB spec.
const (
DescriptorTypeDevice DescriptorType = C.LIBUSB_DT_DEVICE
DescriptorTypeConfig DescriptorType = C.LIBUSB_DT_CONFIG
DescriptorTypeString DescriptorType = C.LIBUSB_DT_STRING
DescriptorTypeInterface DescriptorType = C.LIBUSB_DT_INTERFACE
DescriptorTypeEndpoint DescriptorType = C.LIBUSB_DT_ENDPOINT
DescriptorTypeHID DescriptorType = C.LIBUSB_DT_HID
DescriptorTypeReport DescriptorType = C.LIBUSB_DT_REPORT
DescriptorTypePhysical DescriptorType = C.LIBUSB_DT_PHYSICAL
DescriptorTypeHub DescriptorType = C.LIBUSB_DT_HUB
DescriptorTypeDevice DescriptorType = C.LIBUSB_DT_DEVICE
DescriptorTypeConfig DescriptorType = C.LIBUSB_DT_CONFIG
DescriptorTypeString DescriptorType = C.LIBUSB_DT_STRING
DescriptorTypeInterface DescriptorType = C.LIBUSB_DT_INTERFACE
DescriptorTypeCSInterface DescriptorType = 0x24
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@zagrodzki zagrodzki May 17, 2024

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what about CSEndpoint?

also add a comment to specify where the value was sourced from. (in this case I assume this is CDC spec v1.1/1.2?), since this descriptor type is not a part of the USB spec as such.

DescriptorTypeEndpoint DescriptorType = C.LIBUSB_DT_ENDPOINT
DescriptorTypeHID DescriptorType = C.LIBUSB_DT_HID
DescriptorTypeReport DescriptorType = C.LIBUSB_DT_REPORT
DescriptorTypePhysical DescriptorType = C.LIBUSB_DT_PHYSICAL
DescriptorTypeHub DescriptorType = C.LIBUSB_DT_HUB
)

var descriptorTypeDescription = map[DescriptorType]string{
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8 changes: 8 additions & 0 deletions interface.go
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Expand Up @@ -35,6 +35,11 @@ func (i InterfaceDesc) String() string {
return fmt.Sprintf("Interface %d (%d alternate settings)", i.Number, len(i.AltSettings))
}

type RawDescriptor struct {
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@zagrodzki zagrodzki May 17, 2024

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document the type. In particular whether the header of the descriptor (type+length) is a part of the data is an important information here.

Type DescriptorType
Data []byte
}

// InterfaceSetting contains information about a USB interface with a particular
// alternate setting, extracted from the descriptor.
type InterfaceSetting struct {
Expand All @@ -51,6 +56,9 @@ type InterfaceSetting struct {
// Endpoints enumerates the endpoints available on this interface with
// this alternate setting.
Endpoints map[EndpointAddress]EndpointDesc
// Extra interface descriptors, these are descriptors that are not part of the USB spec
// Potential examples are Class-Specific VC Interface Descriptor (UVC spec)
ExtraDescriptors []*RawDescriptor

iInterface int // index of a string descriptor describing this interface.
}
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27 changes: 21 additions & 6 deletions libusb.go
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Expand Up @@ -301,13 +301,28 @@ func (libusbImpl) getDeviceDesc(d *libusbDevice) (*DeviceDesc, error) {
}
descs := make([]InterfaceSetting, 0, len(alts))
for _, alt := range alts {

var extraDescriptors []*RawDescriptor
extra := C.GoBytes(unsafe.Pointer(alt.extra), alt.extra_length)
for i := 0; i != len(extra); i += int(extra[i]) {
block := extra[i : i+int(extra[i])]
bType := DescriptorType(block[1])

extraDescriptors = append(extraDescriptors,
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@zagrodzki zagrodzki May 17, 2024

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join the line for append (i.e. the &RawDescriptor literal starts in the same line)

&RawDescriptor{
Type: bType,
Data: block},
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@zagrodzki zagrodzki May 17, 2024

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closing curly brace on the next line, together with closing parenthesis

)
}

Comment on lines +305 to +317
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@zagrodzki zagrodzki May 17, 2024

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extract to a helper function, since we're going to use that on interfaces as well as endpoints and configs.

i := InterfaceSetting{
Number: int(alt.bInterfaceNumber),
Alternate: int(alt.bAlternateSetting),
Class: Class(alt.bInterfaceClass),
SubClass: Class(alt.bInterfaceSubClass),
Protocol: Protocol(alt.bInterfaceProtocol),
iInterface: int(alt.iInterface),
Number: int(alt.bInterfaceNumber),
Alternate: int(alt.bAlternateSetting),
Class: Class(alt.bInterfaceClass),
SubClass: Class(alt.bInterfaceSubClass),
Protocol: Protocol(alt.bInterfaceProtocol),
ExtraDescriptors: extraDescriptors,
iInterface: int(alt.iInterface),
}

if hasIntf[i.Number][i.Alternate] {
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