sys/linux/vusb.txt

# Copyright 2019 syzkaller project authors. All rights reserved.
# Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.

include <linux/types.h>
include <linux/byteorder/generic.h>

include <uapi/linux/usb/ch9.h>
include <uapi/linux/usb/ch11.h>

include <uapi/linux/usb/audio.h>
include <uapi/linux/hid.h>
include <linux/hid.h>
include <uapi/linux/usb/cdc.h>
include <uapi/linux/if_ether.h>
include <linux/interrupt.h>
include <linux/usb/cdc_ncm.h>
include <drivers/net/usb/asix.h>

# This is a special fd for USB fuzzing and should only be used with syz_usb_* syzcalls.
# We don't inherit it from the fd resource, to discourage syzkaller calling raw ioctls on it.
resource fd_usb[int32]: -1
resource fd_usb_hid[fd_usb]
resource fd_usb_printer[fd_usb]
resource fd_usb_cdc_ecm[fd_usb]
resource fd_usb_cdc_ncm[fd_usb]
resource fd_usb_uac1[fd_usb]

# These are generic syzcalls for emulating arbitrary USB devices.
# They are mostly targeted to cover the enumeration process.
syz_usb_connect(speed flags[usb_device_speed], dev_len len[dev], dev ptr[in, usb_device_descriptor], conn_descs ptr[in, vusb_connect_descriptors]) fd_usb
syz_usb_control_io(fd fd_usb, descs ptr[in, vusb_descriptors], resps ptr[in, vusb_responses])
syz_usb_ep_write(fd fd_usb, ep int16[0:31], len len[data], data buffer[in])
syz_usb_ep_read(fd fd_usb, ep int16[0:31], len len[data], data buffer[out])
syz_usb_disconnect(fd fd_usb)

# These syzcalls specifically target the HID device class.
syz_usb_connect$hid(speed flags[usb_device_speed], dev_len len[dev], dev ptr[in, usb_device_descriptor_hid], conn_descs ptr[in, vusb_connect_descriptors]) fd_usb_hid
syz_usb_control_io$hid(fd fd_usb_hid, descs ptr[in, vusb_descriptors_hid], resps ptr[in, vusb_responses_hid])

# These syzcalls specifically target the PRINTER device class.
syz_usb_connect$printer(speed flags[usb_device_speed], dev_len len[dev], dev ptr[in, usb_device_descriptor_printer], conn_descs ptr[in, vusb_connect_descriptors]) fd_usb_printer
syz_usb_control_io$printer(fd fd_usb_printer, descs ptr[in, vusb_descriptors_printer], resps ptr[in, vusb_responses_printer])

# These syzcalls specifically target the CDC ECM (Ethernet) device class.
syz_usb_connect$cdc_ecm(speed flags[usb_device_speed], dev_len len[dev], dev ptr[in, usb_device_descriptor_cdc_ecm], conn_descs ptr[in, vusb_connect_descriptors]) fd_usb_cdc_ecm
syz_usb_control_io$cdc_ecm(fd fd_usb_cdc_ecm, descs ptr[in, vusb_descriptors_cdc_ecm], resps ptr[in, vusb_responses_cdc_ecm])

# These syzcalls specifically target the CDC NCM device class.
syz_usb_connect$cdc_ncm(speed flags[usb_device_speed], dev_len len[dev], dev ptr[in, usb_device_descriptor_cdc_ncm], conn_descs ptr[in, vusb_connect_descriptors]) fd_usb_cdc_ncm
syz_usb_control_io$cdc_ncm(fd fd_usb_cdc_ncm, descs ptr[in, vusb_descriptors_cdc_ncm], resps ptr[in, vusb_responses_cdc_ncm])

# These syzcalls specifically target the UAC1 device class.
syz_usb_connect$uac1(speed flags[usb_device_speed], dev_len len[dev], dev ptr[in, usb_device_descriptor_uac1], conn_descs ptr[in, vusb_connect_descriptors]) fd_usb_uac1
syz_usb_control_io$uac1(fd fd_usb_uac1, descs ptr[in, vusb_descriptors_uac1], resps ptr[in, vusb_responses_uac1])

usb_device_speed = USB_SPEED_UNKNOWN, USB_SPEED_LOW, USB_SPEED_FULL, USB_SPEED_HIGH, USB_SPEED_WIRELESS, USB_SPEED_SUPER, USB_SPEED_SUPER_PLUS

# TODO: consider patching idVendor and idProduct for all classes in Go code.

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type usb_device_descriptor_t[CLASS, SUBCLASS, PROTOCOL, VENDOR, PRODUCT, DEVICE, CFS] {
	bLength			const[USB_DT_DEVICE_SIZE, int8]
	bDescriptorType		const[USB_DT_DEVICE, int8]

	bcdUSB			flags[usb_versions, int16]
	bDeviceClass		const[CLASS, int8]
	bDeviceSubClass		const[SUBCLASS, int8]
	bDeviceProtocol		const[PROTOCOL, int8]
	bMaxPacketSize0		flags[usb_device_max_packet_sizes, int8]
	idVendor		const[VENDOR, int16]
	idProduct		const[PRODUCT, int16]
	bcdDevice		const[DEVICE, int16]
	iManufacturer		const[1, int8]
	iProduct		const[2, int8]
	iSerialNumber		const[3, int8]
	bNumConfigurations	len[configs, int8]

	configs			CFS
} [packed]

usb_versions = 0x110, 0x200, 0x201, 0x250, 0x300, 0x310

# https://elixir.bootlin.com/linux/v5.1.7/source/drivers/usb/core/hub.c#L4661
# TODO: dummy driver has complex requirements for packet sizes, account for those:
# https://elixir.bootlin.com/linux/v5.3.6/source/drivers/usb/gadget/udc/dummy_hcd.c#L497
usb_device_max_packet_sizes = 8, 16, 32, 64, 255

type usb_config_descriptor_t[NUM, IFSNUM, ATTRS, IFS] {
	bLength			const[USB_DT_CONFIG_SIZE, int8]
	bDescriptorType		const[USB_DT_CONFIG, int8]

	wTotalLength		len[parent, int16]
	bNumInterfaces		IFSNUM
	bConfigurationValue	NUM
	iConfiguration		int8
	bmAttributes		ATTRS
	bMaxPower		int8

	interfaces		IFS
} [packed]

type usb_config_descriptor_ifaces_array_t[NUM, ATTRS, IFS] usb_config_descriptor_t[NUM, len[interfaces, int8], ATTRS, IFS]

type usb_interface_descriptor_t[IFNUM, ALTNUM, EPSNUM, CLASS, SUBCLASS, PROTOCOL, EXTRA, EPS] {
	bLength			const[USB_DT_INTERFACE_SIZE, int8]
	bDescriptorType		const[USB_DT_INTERFACE, int8]

	bInterfaceNumber	IFNUM
	bAlternateSetting	ALTNUM
	bNumEndpoints		EPSNUM
	bInterfaceClass		CLASS
	bInterfaceSubClass	SUBCLASS
	bInterfaceProtocol	PROTOCOL
	iInterface		int8

	extra			EXTRA
	endpoints		EPS
} [packed]

type usb_interface_descriptor_eps_array_t[IFNUM, ALTNUM, CLASS, SUBCLASS, PROTOCOL, EXTRA, EPS] usb_interface_descriptor_t[IFNUM, ALTNUM, len[endpoints, int8], CLASS, SUBCLASS, PROTOCOL, EXTRA, EPS]
type usb_interface_descriptor_consts_t[IFNUM, ALTNUM, EPSNUM, CLASS, SUBCLASS, PROTOCOL, EXTRA, EPS] usb_interface_descriptor_t[const[IFNUM, int8], const[ALTNUM, int8], const[EPSNUM, int8], const[CLASS, int8], const[SUBCLASS, int8], const[PROTOCOL, int8], EXTRA, EPS]

# TODO: Some endpoints have USB_DT_ENDPOINT_SIZE.
type usb_endpoint_descriptor_t[ADDR, ATTRS, EXTRA] {
	bLength			const[USB_DT_ENDPOINT_AUDIO_SIZE, int8]
	bDescriptorType		const[USB_DT_ENDPOINT, int8]

	bEndpointAddress	ADDR
	bmAttributes		ATTRS
	wMaxPacketSize		int16[0:1024]
	bInterval		int8

	bRefresh		int8
	bSynchAddress		int8

	extra			EXTRA
} [packed]

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# Generic USB device, configuration, interface and endpoint descriptors.

# We only support one configuration per device.
# bDeviceClass, bDeviceSubClass, bDeviceProtocol, idVendor, idProduct
# and bcdDevice are patched by Go code, see sys/linux/init_vusb.go.
usb_device_descriptor {
	inner	usb_device_descriptor_t[0, 0, 0, 0, 0, 0, array[usb_config_descriptor, 1]]
} [packed]

usb_config_descriptor {
	inner	usb_config_descriptor_ifaces_array_t[int8, flags[usb_config_attributes, int8], array[usb_interface_descriptor, 1:4]]
} [packed]

usb_config_attributes = USB_CONFIG_ATT_ONE, USB_CONFIG_ATT_SELFPOWER, USB_CONFIG_ATT_WAKEUP, USB_CONFIG_ATT_BATTERY

# bInterfaceNumber, bInterfaceClass, bInterfaceSubClass and bInterfaceProtocol
# are patched by Go code, see sys/linux/init_vusb.go.
usb_interface_descriptor {
	inner	usb_interface_descriptor_eps_array_t[int8, int8, const[0, int8], const[0, int8], const[0, int8], array[usb_interface_extra_descriptor, 0:2], array[usb_endpoint_descriptor, 0:16]]
} [packed]

usb_endpoint_descriptor {
	inner	usb_endpoint_descriptor_t[flags[usb_endpoint_addresses, int8], flags[usb_endpoint_attributes, int8], array[usb_endpoint_extra_descriptor, 0:2]]
} [packed]

usb_endpoint_addresses = 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, USB_DIR_OUT, USB_DIR_IN

usb_endpoint_attributes = USB_ENDPOINT_XFER_CONTROL, USB_ENDPOINT_XFER_ISOC, USB_ENDPOINT_XFER_BULK, USB_ENDPOINT_XFER_INT, USB_ENDPOINT_INTR_PERIODIC, USB_ENDPOINT_INTR_NOTIFICATION, USB_ENDPOINT_SYNC_NONE, USB_ENDPOINT_SYNC_ASYNC, USB_ENDPOINT_SYNC_ADAPTIVE, USB_ENDPOINT_SYNC_SYNC, USB_ENDPOINT_USAGE_DATA, USB_ENDPOINT_USAGE_FEEDBACK, USB_ENDPOINT_USAGE_FEEDBACK

# TODO: define this struct for each class.
vusb_connect_descriptors {
	qual_len	len[qual, int32]
	qual		ptr[in, usb_qualifier_descriptor]
	bos_len		len[bos, int32]
	bos		ptr[in, usb_bos_descriptor]
	strs_len	len[strs, int32]
	strs		array[vusb_connect_string_descriptor]
} [packed]

vusb_connect_string_descriptor {
	len	len[str, int32]
	str	ptr[in, usb_string_descriptor]
} [packed]

vusb_descriptors {
	len	len[parent, int32]
	generic	ptr[in, vusb_descriptor_generic]

	string	ptr[in, vusb_descriptor_t[USB_TYPE_STANDARD, USB_DT_STRING, usb_string_descriptor]]
	bos	ptr[in, vusb_descriptor_t[USB_TYPE_STANDARD, USB_DT_BOS, usb_bos_descriptor]]

	hub_hs	ptr[in, vusb_descriptor_t[USB_TYPE_CLASS, USB_DT_HUB, usb_hub_descriptor_hs]]
	hub_ss	ptr[in, vusb_descriptor_t[USB_TYPE_CLASS, USB_DT_SS_HUB, usb_hub_descriptor_ss]]
} [packed]

vusb_descriptor_generic {
	req_type	flags[usb_request_types, int8]
	desc_type	flags[usb_descriptor_types, int8]
	len		bytesize[data, int32]
	data		usb_generic_descriptor
} [packed]

usb_request_types = USB_TYPE_STANDARD, USB_TYPE_CLASS, USB_TYPE_VENDOR

type vusb_descriptor_t[CLASS, REQ, DATA] {
	type	const[CLASS, int8]
	req	const[REQ, int8]
	len	bytesize[data, int32]
	data	DATA
} [packed]

# TODO: consider doing lookups based on USB_RECIP values.
# TODO: split out class and driver specific responses into separate structs.
vusb_responses {
	len				len[parent, int32]
	generic				ptr[in, vusb_response_generic]

	get_interface			ptr[in, vusb_response_t[USB_TYPE_STANDARD, USB_REQ_GET_INTERFACE, int8]]
	get_configuration		ptr[in, vusb_response_t[USB_TYPE_STANDARD, USB_REQ_GET_CONFIGURATION, int8]]

	hub_USB_REQ_GET_STATUS_hub	ptr[in, vusb_response_t[USB_TYPE_CLASS, USB_REQ_GET_STATUS, usb_hub_status]]
	hub_USB_REQ_GET_STATUS_port	ptr[in, vusb_response_t[USB_TYPE_CLASS, USB_REQ_GET_STATUS, usb_port_status]]

	asix_AX_CMD_READ_MII_REG	ptr[in, vusb_response_t[USB_TYPE_VENDOR, AX_CMD_READ_MII_REG, int16]]
	asix_AX_CMD_STATMNGSTS_REG	ptr[in, vusb_response_t[USB_TYPE_VENDOR, AX_CMD_STATMNGSTS_REG, int8]]
	asix_AX_CMD_READ_EEPROM		ptr[in, vusb_response_t[USB_TYPE_VENDOR, AX_CMD_READ_EEPROM, array[int8, 2]]]
	asix_AX_CMD_READ_RX_CTL		ptr[in, vusb_response_t[USB_TYPE_VENDOR, AX_CMD_READ_RX_CTL, int16]]
	asix_AX_CMD_READ_NODE_ID	ptr[in, vusb_response_t[USB_TYPE_VENDOR, AX_CMD_READ_NODE_ID, mac_addr]]
	asix_AX88172_CMD_READ_NODE_ID	ptr[in, vusb_response_t[USB_TYPE_VENDOR, AX88172_CMD_READ_NODE_ID, mac_addr]]
	asix_AX_CMD_READ_PHY_ID		ptr[in, vusb_response_t[USB_TYPE_VENDOR, AX_CMD_READ_PHY_ID, array[int8, 2]]]
	asix_AX_CMD_READ_MEDIUM_STATUS	ptr[in, vusb_response_t[USB_TYPE_VENDOR, AX_CMD_READ_MEDIUM_STATUS, int16]]
	asix_AX_CMD_READ_MONITOR_MODE	ptr[in, vusb_response_t[USB_TYPE_VENDOR, AX_CMD_READ_MONITOR_MODE, int8]]
	asix_AX_CMD_READ_GPIOS		ptr[in, vusb_response_t[USB_TYPE_VENDOR, AX_CMD_READ_GPIOS, int8]]
	asix_AX_CMD_SW_PHY_STATUS	ptr[in, vusb_response_t[USB_TYPE_VENDOR, AX_CMD_SW_PHY_STATUS, int8]]
} [packed]

vusb_response_generic {
	type	flags[usb_request_types, int8]
	req	flags[usb_requests, int8]
	len	bytesize[data, int32]
	data	array[int8]
} [packed]

usb_requests = USB_REQ_GET_STATUS, USB_REQ_CLEAR_FEATURE, USB_REQ_SET_FEATURE, USB_REQ_SET_ADDRESS, USB_REQ_GET_DESCRIPTOR, USB_REQ_SET_DESCRIPTOR, USB_REQ_GET_CONFIGURATION, USB_REQ_SET_CONFIGURATION, USB_REQ_GET_INTERFACE, USB_REQ_SET_INTERFACE, USB_REQ_SYNCH_FRAME, USB_REQ_SET_SEL, USB_REQ_SET_ISOCH_DELAY, USB_REQ_SET_ENCRYPTION, USB_REQ_GET_ENCRYPTION, USB_REQ_RPIPE_ABORT, USB_REQ_SET_HANDSHAKE, USB_REQ_RPIPE_RESET, USB_REQ_GET_HANDSHAKE, USB_REQ_SET_CONNECTION, USB_REQ_SET_SECURITY_DATA, USB_REQ_GET_SECURITY_DATA, USB_REQ_SET_WUSB_DATA, USB_REQ_LOOPBACK_DATA_WRITE, USB_REQ_LOOPBACK_DATA_READ, USB_REQ_SET_INTERFACE_DS, USB_REQ_GET_PARTNER_PDO, USB_REQ_GET_BATTERY_STATUS, USB_REQ_SET_PDO, USB_REQ_GET_VDM, USB_REQ_SEND_VDM

type vusb_response_t[CLASS, REQ, DATA] {
	type	const[CLASS, int8]
	req	const[REQ, int8]
	len	bytesize[data, int32]
	data	DATA
} [packed]

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# USB descriptors requested by the kernel before the SET_CONFIGURATION request.

# TODO: figure out when is the USB_DT_OTG descriptor used.
# TODO: figure out when is the USB_DT_INTERFACE_ASSOCIATION descriptor used.

type usb_string_descriptor_t[DATA] {
	bLength		len[parent, int8]
	bDescriptorType	const[USB_DT_STRING, int8]

	data		DATA
} [packed]

usb_string_descriptor [
	lang_id	usb_string_descriptor_t[flags[usb_lang_ids, int16]]
	string	usb_string_descriptor_t[array[int8]]
] [varlen]

usb_lang_ids = 0x436, 0x41c, 0x401, 0x801, 0xc01, 0x1001, 0x1401, 0x1801, 0x1c01, 0x2001, 0x2401, 0x2801, 0x2c01, 0x3001, 0x3401, 0x3801, 0x3c01, 0x4001, 0x42b, 0x44d, 0x42c, 0x82c, 0x42d, 0x423, 0x445, 0x402, 0x455, 0x403, 0x404, 0x804, 0xc04, 0x1004, 0x1404, 0x41a, 0x405, 0x406, 0x413, 0x813, 0x409, 0x809, 0xc09, 0x1009, 0x1409, 0x1809, 0x1c09, 0x2009, 0x2409, 0x2809, 0x2c09, 0x3009, 0x3409, 0x425, 0x438, 0x429, 0x40b, 0x40c, 0x80c, 0xc0c, 0x100c, 0x140c, 0x180c, 0x437, 0x407, 0x807, 0xc07, 0x1007, 0x1407, 0x408, 0x447, 0x40d, 0x439, 0x40e, 0x40f, 0x421, 0x410, 0x810, 0x411, 0x44b, 0x860, 0x43f, 0x457, 0x412, 0x812, 0x426, 0x427, 0x827, 0x42f, 0x43e, 0x83e, 0x44c, 0x458, 0x44e, 0x861, 0x414, 0x814, 0x448, 0x415, 0x416, 0x816, 0x446, 0x418, 0x419, 0x44f, 0xc1a, 0x81a, 0x459, 0x41b, 0x424, 0x40a, 0x80a, 0xc0a, 0x100a, 0x140a, 0x180a, 0x1c0a, 0x200a, 0x240a, 0x280a, 0x2c0a, 0x300a, 0x340a, 0x380a, 0x3c0a, 0x400a, 0x440a, 0x480a, 0x4c0a, 0x500a, 0x430, 0x441, 0x41d, 0x81d, 0x449, 0x444, 0x44a, 0x41e, 0x41f, 0x422, 0x420, 0x820, 0x443, 0x843, 0x42a, 0x4ff, 0xf0ff, 0xf4ff, 0xf8ff, 0xfcff

usb_qualifier_descriptor {
	bLength			len[parent, int8]
	bDescriptorType		const[USB_DT_DEVICE_QUALIFIER, int8]

	bcdUSB			flags[usb_versions, int16]
	bDeviceClass		int8
	bDeviceSubClass		int8
	bDeviceProtocol		int8
	bMaxPacketSize0		flags[usb_device_max_packet_sizes, int8]
	bNumConfigurations	int8
	bRESERVED		const[0, int8]
} [packed]

# TODO: investigate which devices are required to have this descriptor.
usb_bos_descriptor {
	bLength		const[USB_DT_BOS_SIZE, int8]
	bDescriptorType	const[USB_DT_BOS, int8]

	wTotalLength	len[parent, int16]
	bNumDeviceCaps	len[caps, int8]

	caps		array[usb_dev_cap, 0:6]
} [packed]

usb_dev_cap [
	generic		usb_generic_cap_descriptor
	wireless	usb_wireless_cap_descriptor
	ext_cap		usb_ext_cap_descriptor
	ss_cap		usb_ss_cap_descriptor
	ss_container_id	usb_ss_container_id_descriptor
	ssp_cap		usb_ssp_cap_descriptor
	ptm_cap		usb_ptm_cap_descriptor
] [varlen]

usb_generic_cap_descriptor {
	bLength			len[parent, int8]
	bDescriptorType		const[USB_DT_DEVICE_CAPABILITY, int8]
	bDevCapabilityType	flags[usb_capability_types, int8]

	data			array[int8]
} [packed]

usb_capability_types = USB_CAP_TYPE_WIRELESS_USB, USB_CAP_TYPE_EXT, USB_SS_CAP_TYPE, USB_SSP_CAP_TYPE, CONTAINER_ID_TYPE, USB_PTM_CAP_TYPE

usb_wireless_cap_descriptor {
	bLength			len[parent, int8]
	bDescriptorType		const[USB_DT_DEVICE_CAPABILITY, int8]
	bDevCapabilityType	const[USB_CAP_TYPE_WIRELESS_USB, int8]

	bmAttributes		flags[usb_wireless_cap_attributes, int8]
	wPHYRates		flags[usb_wireless_cap_phyrates, int16]
	bmTFITXPowerInfo	int8
	bmFFITXPowerInfo	int8
	bmBandGroup		int16
	bReserved		int8
} [packed]

usb_wireless_cap_attributes = USB_WIRELESS_P2P_DRD, USB_WIRELESS_BEACON_MASK, USB_WIRELESS_BEACON_SELF, USB_WIRELESS_BEACON_DIRECTED, USB_WIRELESS_BEACON_NONE

usb_wireless_cap_phyrates = USB_WIRELESS_PHY_53, USB_WIRELESS_PHY_80, USB_WIRELESS_PHY_107, USB_WIRELESS_PHY_160, USB_WIRELESS_PHY_200, USB_WIRELESS_PHY_320, USB_WIRELESS_PHY_400, USB_WIRELESS_PHY_480

usb_ext_cap_descriptor {
	bLength			len[parent, int8]
	bDescriptorType		const[USB_DT_DEVICE_CAPABILITY, int8]
	bDevCapabilityType	const[USB_CAP_TYPE_EXT, int8]

	bmAttributes1		flags[usb_ext_cap_attributes, int32:8]
	bmAttributes2		int32:4
	bmAttributes3		int32:4
	bmAttributes4		int32:16
} [packed]

usb_ext_cap_attributes = USB_LPM_SUPPORT, USB_BESL_SUPPORT, USB_BESL_BASELINE_VALID, USB_BESL_DEEP_VALID

usb_ss_cap_descriptor {
	bLength			len[parent, int8]
	bDescriptorType		const[USB_DT_DEVICE_CAPABILITY, int8]
	bDevCapabilityType	const[USB_SS_CAP_TYPE, int8]

	bmAttributes		flags[usb_ss_cap_attributes, int8]
	wSpeedSupported		flags[usb_ss_cap_speed, int16]
	bFunctionalitySupport	int8
	bU1devExitLat		int8
	bU2DevExitLat		int16
} [packed]

usb_ss_cap_attributes = USB_LTM_SUPPORT

usb_ss_cap_speed = USB_LOW_SPEED_OPERATION, USB_FULL_SPEED_OPERATION, USB_HIGH_SPEED_OPERATION, USB_5GBPS_OPERATION

usb_ss_container_id_descriptor {
	bLength			len[parent, int8]
	bDescriptorType		const[USB_DT_DEVICE_CAPABILITY, int8]
	bDevCapabilityType	const[CONTAINER_ID_TYPE, int8]

	bReserved		int8
	ContainerID		array[int8, 16]
} [packed]

usb_ssp_cap_descriptor {
	bLength				len[parent, int8]
	bDescriptorType			const[USB_DT_DEVICE_CAPABILITY, int8]
	bDevCapabilityType		const[USB_SSP_CAP_TYPE, int8]

	bReserved			int8
	bmAttributesSublinkSpeeds	len[bmSublinkSpeedAttr, int32:5]
	bmAttributesSpeedIDs		int32:27
	wFunctionalitySupport		flags[usb_ssp_cap_funcs, int16]
	wReserved			int16
	bmSublinkSpeedAttr		array[flags[usb_ssp_cap_sublink_speeds, int32], 0:6]
} [packed]

usb_ssp_cap_funcs = USB_SSP_MIN_SUBLINK_SPEED_ATTRIBUTE_ID, USB_SSP_MIN_RX_LANE_COUNT, USB_SSP_MIN_TX_LANE_COUNT

usb_ssp_cap_sublink_speeds = USB_SSP_SUBLINK_SPEED_SSID, USB_SSP_SUBLINK_SPEED_LSE, USB_SSP_SUBLINK_SPEED_ST, USB_SSP_SUBLINK_SPEED_RSVD, USB_SSP_SUBLINK_SPEED_LP, USB_SSP_SUBLINK_SPEED_LSM

usb_ptm_cap_descriptor {
	bLength			len[parent, int8]
	bDescriptorType		const[USB_DT_DEVICE_CAPABILITY, int8]
	bDevCapabilityType	const[USB_PTM_CAP_TYPE, int8]
} [packed]

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# Extra USB descriptors that come after an interface or an endpoint descriptor.

# TODO: rework this union so each option is a single descriptor.
usb_interface_extra_descriptor [
	generic		usb_generic_descriptor
	hid_hid		usb_hid_descriptor_hid
	cdc_ecm		usb_cdc_header_ecm
	cdc_ncm		usb_cdc_header_ncm
	uac_control	uac_control_iface_extra_descriptors
	uac_as		uac_as_iface_extra_descriptors
] [varlen]

usb_endpoint_extra_descriptor [
	generic	usb_generic_descriptor
	uac_iso	uac_iso_endpoint_descriptor
] [varlen]

usb_generic_descriptor {
	bLength		len[parent, int8]
	bDescriptorType	flags[usb_descriptor_types, int8]

	data		array[int8]
} [packed]

usb_descriptor_types = USB_DT_DEVICE, USB_DT_CONFIG, USB_DT_STRING, USB_DT_INTERFACE, USB_DT_ENDPOINT, USB_DT_DEVICE_QUALIFIER, USB_DT_OTHER_SPEED_CONFIG, USB_DT_INTERFACE_POWER, USB_DT_OTG, USB_DT_DEBUG, USB_DT_INTERFACE_ASSOCIATION, USB_DT_SECURITY, USB_DT_KEY, USB_DT_ENCRYPTION_TYPE, USB_DT_BOS, USB_DT_DEVICE_CAPABILITY, USB_DT_WIRELESS_ENDPOINT_COMP, USB_DT_WIRE_ADAPTER, USB_DT_RPIPE, USB_DT_CS_RADIO_CONTROL, USB_DT_PIPE_USAGE, USB_DT_SS_ENDPOINT_COMP, USB_DT_SSP_ISOC_ENDPOINT_COMP, HID_DT_HID, HID_DT_REPORT, HID_DT_PHYSICAL

# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
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# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #

# USB descriptors requested after the SET_CONFIGURATION request.

usb_hub_descriptor_hs {
	bDescLength		len[parent, int8]
	bDescriptorType		const[USB_DT_HUB, int8]

	bNbrPorts		int8
	wHubCharacteristics	flags[usb_hub_characteristics, int16]
	bPwrOn2PwrGood		int8
	bHubContrCurrent	int8

	DeviceRemovable		array[int8, USB_HUB_PORTS_BITS]
	PortPwrCtrlMask		array[int8, USB_HUB_PORTS_BITS]
} [packed]

usb_hub_descriptor_ss {
	bDescLength		len[parent, int8]
	bDescriptorType		const[USB_DT_SS_HUB, int8]

	bNbrPorts		int8
	wHubCharacteristics	flags[usb_hub_characteristics, int16]
	bPwrOn2PwrGood		int8
	bHubContrCurrent	int8

	bHubHdrDecLat		int8
	wHubDelay		int16
	DeviceRemovable		int16
} [packed]

define USB_HUB_PORTS_BITS	((USB_MAXCHILDREN + 1 + 7) / 8)

usb_hub_characteristics = HUB_CHAR_LPSM, HUB_CHAR_COMMON_LPSM, HUB_CHAR_INDV_PORT_LPSM, HUB_CHAR_NO_LPSM, HUB_CHAR_COMPOUND, HUB_CHAR_OCPM, HUB_CHAR_COMMON_OCPM, HUB_CHAR_INDV_PORT_OCPM, HUB_CHAR_NO_OCPM, HUB_CHAR_TTTT, HUB_CHAR_PORTIND

# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
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# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #

# Replies to USB control requests requested after the SET_CONFIGURATION request.

usb_port_status {
	wPortStatus	flags[usb_port_status_flags, int16]
	wPortChange	flags[usb_port_change_flags, int16]
	dwExtPortStatus	array[flags[usb_ext_port_status_flags, int32], 0:1]
} [packed]

usb_port_status_flags = USB_PORT_STAT_CONNECTION, USB_PORT_STAT_ENABLE, USB_PORT_STAT_SUSPEND, USB_PORT_STAT_OVERCURRENT, USB_PORT_STAT_RESET, USB_PORT_STAT_L1, USB_PORT_STAT_POWER, USB_PORT_STAT_LOW_SPEED, USB_PORT_STAT_HIGH_SPEED, USB_PORT_STAT_TEST, USB_PORT_STAT_INDICATOR, USB_PORT_STAT_LINK_STATE, USB_SS_PORT_STAT_POWER, USB_SS_PORT_STAT_SPEED, USB_PORT_STAT_SPEED_5GBPS, USB_SS_PORT_LS_U0, USB_SS_PORT_LS_U1, USB_SS_PORT_LS_U2, USB_SS_PORT_LS_U3, USB_SS_PORT_LS_SS_DISABLED, USB_SS_PORT_LS_RX_DETECT, USB_SS_PORT_LS_SS_INACTIVE, USB_SS_PORT_LS_POLLING, USB_SS_PORT_LS_RECOVERY, USB_SS_PORT_LS_HOT_RESET, USB_SS_PORT_LS_COMP_MOD, USB_SS_PORT_LS_LOOPBACK

usb_port_change_flags = USB_PORT_STAT_C_CONNECTION, USB_PORT_STAT_C_ENABLE, USB_PORT_STAT_C_SUSPEND, USB_PORT_STAT_C_OVERCURRENT, USB_PORT_STAT_C_RESET, USB_PORT_STAT_C_L1, USB_PORT_STAT_C_BH_RESET, USB_PORT_STAT_C_LINK_STATE, USB_PORT_STAT_C_CONFIG_ERROR

usb_ext_port_status_flags = USB_EXT_PORT_STAT_RX_SPEED_ID, USB_EXT_PORT_STAT_TX_SPEED_ID, USB_EXT_PORT_STAT_RX_LANES, USB_EXT_PORT_STAT_TX_LANES

usb_hub_status {
	wHubStatus	flags[usb_hub_status_flags, int16]
	wHubChange	flags[usb_hub_change_flags, int16]
} [packed]

usb_hub_status_flags = HUB_STATUS_LOCAL_POWER, HUB_STATUS_OVERCURRENT

usb_hub_change_flags = HUB_CHANGE_LOCAL_POWER, HUB_CHANGE_OVERCURRENT

# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
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# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #

# HID device class specific descriptions.
# https://www.usb.org/sites/default/files/documents/hid1_11.pdf
# https://elixir.bootlin.com/linux/latest/source/drivers/hid/usbhid/hid-core.c
# https://elixir.bootlin.com/linux/latest/source/drivers/hid/hid-core.c
# https://elixir.bootlin.com/linux/latest/source/drivers/usb/gadget/legacy/hid.c
# https://elixir.bootlin.com/linux/latest/source/drivers/usb/gadget/function/f_hid.c

# Connected HID devices are known to create the following /dev/ files:
# /dev/hidraw#, /dev/usb/hiddev# and /dev/input/event#.

# idVendor and idProduct are patched by Go code, see sys/linux/init_vusb.go.
usb_device_descriptor_hid {
	inner	usb_device_descriptor_t[0, 0, 0, 0, 0, 64, array[usb_config_descriptor_hid, 1]]
} [packed]

usb_config_descriptor_hid {
	inner	usb_config_descriptor_ifaces_array_t[const[1, int8], flags[usb_config_attributes, int8], array[usb_interface_descriptor_hid, 1]]
} [packed]

usb_interface_descriptor_hid {
	inner	usb_interface_descriptor_t[const[0, int8], int8, int8[1:2], const[USB_CLASS_HID, int8], const[USB_INTERFACE_SUBCLASS_BOOT, int8], flags[usb_hid_protocols, int8], usb_hid_descriptor_hid, usb_endpoint_descriptors_hid]
} [packed]

usb_hid_protocols = 0, USB_INTERFACE_PROTOCOL_KEYBOARD, USB_INTERFACE_PROTOCOL_MOUSE

usb_endpoint_descriptors_hid {
	in	usb_endpoint_descriptor_hid_in
	out	array[usb_endpoint_descriptor_hid_out, 0:1]
} [packed]

usb_endpoint_descriptor_hid_in {
	inner	usb_endpoint_descriptor_t[const[USB_ENDPOINT_HID_IN_ADDRESS, int8], const[USB_ENDPOINT_HID_ATTRIBUTES, int8], void]
} [packed]

usb_endpoint_descriptor_hid_out {
	inner	usb_endpoint_descriptor_t[const[USB_ENDPOINT_HID_OUT_ADDRESS, int8], const[USB_ENDPOINT_HID_ATTRIBUTES, int8], void]
} [packed]

define USB_ENDPOINT_HID_ATTRIBUTES	(USB_ENDPOINT_XFER_INT)
define USB_ENDPOINT_HID_IN_ADDRESS	(1 | USB_DIR_IN)
define USB_ENDPOINT_HID_OUT_ADDRESS	(2)

vusb_descriptors_hid {
	len		len[parent, int32]
	generic		ptr[in, vusb_descriptor_generic]

	USB_DT_STRING	ptr[in, vusb_descriptor_t[USB_TYPE_STANDARD, USB_DT_STRING, usb_string_descriptor]]

# For unknown reasons these are requested as USB_TYPE_STANDARD and not as USB_TYPE_CLASS.
# Linux doesn't request HID_DT_HID, but some hosts might do that.
	HID_DT_REPORT	ptr[in, vusb_descriptor_t[USB_TYPE_STANDARD, HID_DT_REPORT, hid_descriptor_report]]
	HID_DT_HID	ptr[in, vusb_descriptor_t[USB_TYPE_STANDARD, HID_DT_HID, usb_hid_descriptor_hid]]
} [packed]

vusb_responses_hid {
	len				len[parent, int32]
	generic				ptr[in, vusb_response_generic]

	USB_REQ_GET_INTERFACE		ptr[in, vusb_response_t[USB_TYPE_STANDARD, USB_REQ_GET_INTERFACE, int8]]
	USB_REQ_GET_CONFIGURATION	ptr[in, vusb_response_t[USB_TYPE_STANDARD, USB_REQ_GET_CONFIGURATION, int8]]

	HID_REQ_GET_REPORT		ptr[in, vusb_response_t[USB_TYPE_CLASS, HID_REQ_GET_REPORT, array[int8]]]
	HID_REQ_GET_PROTOCOL		ptr[in, vusb_response_t[USB_TYPE_CLASS, HID_REQ_GET_PROTOCOL, int8]]
} [packed]

# USB HID specifications allows for multiple report and physical descriptors
# to be present, but I don't see any support for them in the Linux kernel,
# except for a single report descriptor.
usb_hid_descriptor_hid {
	bLength		len[parent, int8]
	bDescriptorType	const[HID_DT_HID, int8]

	bcdHID		int16
	bCountryCode	int8
	bNumDescriptors	const[1, int8]

	report_desc	usb_hid_class_descriptor_report
} [packed]

usb_hid_class_descriptor_report {
	bDescriptorType		const[HID_DT_REPORT, int8]
	wDescriptorLength	int16[0:HID_MAX_DESCRIPTOR_SIZE]
} [packed]

# TODO: it's hard to describe the REPORT descriptor structure via syzkaller
# descriptions, so consider generating it in Go code.
# TODO: the length of REPORT descriptor must match the value in HID descriptor.
# Linux HID stack doesn't support long items.
# TODO: there are vendor specific REPORT descriptor formats (Logitech HID++).
hid_descriptor_report {
	items	array[hid_report_item_short]
} [packed]

type hid_report_item_short_012_t[TYPE, TAGS] {
	bSize	len[data, int8:2]
	bType	const[TYPE, int8:2]
	bTag	flags[TAGS, int8:4]
	data	array[int8, 0:2]
} [packed]

type hid_report_item_short_4_t[TYPE, TAGS] {
	bSize	const[3, int8:2]
	bType	const[TYPE, int8:2]
	bTag	flags[TAGS, int8:4]
	data	array[int8, 4]
} [packed]

type hid_report_item_short_t[TYPE, TAGS] [
	item_012	hid_report_item_short_012_t[TYPE, TAGS]
	item_4		hid_report_item_short_4_t[TYPE, TAGS]
] [varlen]

hid_report_item_short [
	main	hid_report_item_short_t[HID_ITEM_TYPE_MAIN, hid_report_item_main_tags]
	global	hid_report_item_short_t[HID_ITEM_TYPE_GLOBAL, hid_report_item_global_tags]
	local	hid_report_item_short_t[HID_ITEM_TYPE_LOCAL, hid_report_item_local_tags]
] [varlen]

hid_report_item_main_tags = HID_MAIN_ITEM_TAG_INPUT, HID_MAIN_ITEM_TAG_OUTPUT, HID_MAIN_ITEM_TAG_FEATURE, HID_MAIN_ITEM_TAG_BEGIN_COLLECTION, HID_MAIN_ITEM_TAG_END_COLLECTION
hid_report_item_global_tags = HID_GLOBAL_ITEM_TAG_USAGE_PAGE, HID_GLOBAL_ITEM_TAG_LOGICAL_MINIMUM, HID_GLOBAL_ITEM_TAG_LOGICAL_MAXIMUM, HID_GLOBAL_ITEM_TAG_PHYSICAL_MINIMUM, HID_GLOBAL_ITEM_TAG_PHYSICAL_MAXIMUM, HID_GLOBAL_ITEM_TAG_UNIT_EXPONENT, HID_GLOBAL_ITEM_TAG_UNIT, HID_GLOBAL_ITEM_TAG_REPORT_SIZE, HID_GLOBAL_ITEM_TAG_REPORT_ID, HID_GLOBAL_ITEM_TAG_REPORT_COUNT, HID_GLOBAL_ITEM_TAG_PUSH, HID_GLOBAL_ITEM_TAG_POP
hid_report_item_local_tags = HID_LOCAL_ITEM_TAG_USAGE, HID_LOCAL_ITEM_TAG_USAGE_MINIMUM, HID_LOCAL_ITEM_TAG_USAGE_MAXIMUM, HID_LOCAL_ITEM_TAG_DESIGNATOR_INDEX, HID_LOCAL_ITEM_TAG_DESIGNATOR_MINIMUM, HID_LOCAL_ITEM_TAG_DESIGNATOR_MAXIMUM, HID_LOCAL_ITEM_TAG_STRING_INDEX, HID_LOCAL_ITEM_TAG_STRING_MINIMUM, HID_LOCAL_ITEM_TAG_STRING_MAXIMUM, HID_LOCAL_ITEM_TAG_DELIMITER

# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #

# PRINTER device class specific descriptions.
# https://www.usb.org/sites/default/files/usbprint11a021811.pdf
# https://elixir.bootlin.com/linux/latest/source/drivers/usb/class/usblp.c
# https://elixir.bootlin.com/linux/latest/source/drivers/usb/gadget/legacy/printer.c
# https://elixir.bootlin.com/linux/latest/source/drivers/usb/gadget/function/f_printer.c

# Connected PRINTER devices are known to create the following /dev/ files:
# /dev/usb/lp#.
# TODO: write descriptions for it.

# drivers/usb/class/usblp.c
define USBLP_REQ_GET_ID	0x00
define USBLP_REQ_GET_STATUS	0x01
define USBLP_REQ_RESET	0x02
define USBLP_REQ_HP_CHANNEL_CHANGE_REQUEST	0x00
define USBLP_FIRST_PROTOCOL	1
define USBLP_LAST_PROTOCOL	3

usb_device_descriptor_printer {
	inner	usb_device_descriptor_t[0, 0, 0, 0x525, 0xa4a8, 64, array[usb_config_descriptor_printer, 1]]
} [packed]

usb_config_descriptor_printer {
	inner	usb_config_descriptor_ifaces_array_t[const[1, int8], flags[usb_config_attributes, int8], array[usb_interface_descriptor_printer, 1]]
} [packed]

usb_interface_descriptor_printer {
	inner	usb_interface_descriptor_t[const[0, int8], int8, int8[1:2], const[USB_CLASS_PRINTER, int8], const[1, int8], int8[USBLP_FIRST_PROTOCOL:USBLP_LAST_PROTOCOL], void, usb_endpoint_descriptors_printer]
} [packed]

usb_endpoint_descriptors_printer {
	in	usb_endpoint_descriptor_printer_out
	out	array[usb_endpoint_descriptor_printer_in, 0:1]
} [packed]

usb_endpoint_descriptor_printer_out {
	inner	usb_endpoint_descriptor_t[const[USB_ENDPOINT_PRINTER_OUT_ADDRESS, int8], const[USB_ENDPOINT_PRINTER_ATTRIBUTES, int8], void]
} [packed]

usb_endpoint_descriptor_printer_in {
	inner	usb_endpoint_descriptor_t[const[USB_ENDPOINT_PRINTER_IN_ADDRESS, int8], const[USB_ENDPOINT_PRINTER_ATTRIBUTES, int8], void]
} [packed]

define USB_ENDPOINT_PRINTER_ATTRIBUTES	(USB_ENDPOINT_XFER_BULK)
define USB_ENDPOINT_PRINTER_OUT_ADDRESS	(1)
define USB_ENDPOINT_PRINTER_IN_ADDRESS	(2 | USB_DIR_IN)

vusb_descriptors_printer {
	len		len[parent, int32]
	generic		ptr[in, vusb_descriptor_generic]

	USB_DT_STRING	ptr[in, vusb_descriptor_t[USB_TYPE_STANDARD, USB_DT_STRING, usb_string_descriptor]]
} [packed]

vusb_responses_printer {
	len					len[parent, int32]
	generic					ptr[in, vusb_response_generic]

	USB_REQ_GET_INTERFACE			ptr[in, vusb_response_t[USB_TYPE_STANDARD, USB_REQ_GET_INTERFACE, int8]]
	USB_REQ_GET_CONFIGURATION		ptr[in, vusb_response_t[USB_TYPE_STANDARD, USB_REQ_GET_CONFIGURATION, int8]]

	USBLP_REQ_GET_ID			ptr[in, vusb_response_t[USB_TYPE_CLASS, USBLP_REQ_GET_ID, usb_printer_get_id_response]]
	USBLP_REQ_GET_STATUS			ptr[in, vusb_response_t[USB_TYPE_CLASS, USBLP_REQ_GET_STATUS, int8]]
	USBLP_REQ_HP_CHANNEL_CHANGE_REQUEST	ptr[in, vusb_response_t[USB_TYPE_CLASS, USBLP_REQ_HP_CHANNEL_CHANGE_REQUEST, int8]]
} [packed]

usb_printer_get_id_response {
	length	len[id, int16be]
	id	array[int8]
} [packed]

# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #

# CDC ECM (Ethernet) device class specific descriptions.
# https://www.usb.org/document-library/class-definitions-communication-devices-12
# https://elixir.bootlin.com/linux/latest/source/drivers/net/usb/cdc_ether.c
# https://elixir.bootlin.com/linux/latest/source/drivers/net/usb/usbnet.c
# https://elixir.bootlin.com/linux/latest/source/drivers/usb/gadget/legacy/ether.c
# https://elixir.bootlin.com/linux/latest/source/drivers/usb/gadget/function/f_ecm.c
# https://elixir.bootlin.com/linux/latest/source/drivers/usb/gadget/function/u_ether.c

# Connected CDC ECM devices are known to create usbN network interfaces.
# TODO: enable fuzzing of those.

usb_device_descriptor_cdc_ecm {
	inner	usb_device_descriptor_t[USB_CLASS_COMM, 0, 0, 0x525, 0xa4a1, 64, array[usb_config_descriptor_cdc_ecm, 1]]
} [packed]

usb_config_descriptor_cdc_ecm {
	inner	usb_config_descriptor_ifaces_array_t[const[1, int8], flags[usb_config_attributes, int8], array[usb_interface_descriptor_cdc_ecm, 1]]
} [packed]

# Per specification CDC ECM devices have two interfaces (control and data),
# but here we're merging them into one for simplicity since Linux supports that.
usb_interface_descriptor_cdc_ecm {
	inner	usb_interface_descriptor_t[const[0, int8], int8, int8[2:3], const[USB_CLASS_COMM, int8], const[USB_CDC_SUBCLASS_ETHERNET, int8], const[USB_CDC_PROTO_NONE, int8], usb_cdc_header_ecm, usb_endpoint_descriptors_cdc_ecm]
} [packed]

usb_endpoint_descriptors_cdc_ecm {
	notify	array[usb_endpoint_descriptor_cdc_ecm_notify, 0:1]
	in	usb_endpoint_descriptor_cdc_ecm_in
	out	usb_endpoint_descriptor_cdc_ecm_out
} [packed]

usb_endpoint_descriptor_cdc_ecm_notify {
	inner	usb_endpoint_descriptor_t[const[USB_ENDPOINT_CDC_ECM_NOTIFY_ADDRESS, int8], const[USB_ENDPOINT_CDC_ECM_NOTIFY_ATTRIBUTES, int8], void]
} [packed]

usb_endpoint_descriptor_cdc_ecm_in {
	inner	usb_endpoint_descriptor_t[const[USB_ENDPOINT_CDC_ECM_IN_ADDRESS, int8], const[USB_ENDPOINT_CDC_ECM_DATA_ATTRIBUTES, int8], void]
} [packed]

usb_endpoint_descriptor_cdc_ecm_out {
	inner	usb_endpoint_descriptor_t[const[USB_ENDPOINT_CDC_ECM_OUT_ADDRESS, int8], const[USB_ENDPOINT_CDC_ECM_DATA_ATTRIBUTES, int8], void]
} [packed]

define USB_ENDPOINT_CDC_ECM_NOTIFY_ATTRIBUTES	(USB_ENDPOINT_XFER_INT)
define USB_ENDPOINT_CDC_ECM_DATA_ATTRIBUTES	(USB_ENDPOINT_XFER_BULK)
define USB_ENDPOINT_CDC_ECM_NOTIFY_ADDRESS	(1 | USB_DIR_IN)
define USB_ENDPOINT_CDC_ECM_IN_ADDRESS	(2 | USB_DIR_IN)
define USB_ENDPOINT_CDC_ECM_OUT_ADDRESS	(3)

# https://elixir.bootlin.com/linux/v5.2.7/source/drivers/usb/core/message.c#L2137
# https://elixir.bootlin.com/linux/v5.2.7/source/drivers/net/usb/cdc_ether.c#L155
usb_cdc_header_ecm {
	union	usb_cdc_union_desc_t[0, 0]
	header	usb_cdc_header_desc
	ether	usb_cdc_ether_desc

	other	array[usb_cdc_header_ecm_other, 0:6]
} [packed]

usb_cdc_header_ecm_other [
	call_mgmt		usb_cdc_call_mgmt_descriptor
	acm			usb_cdc_acm_descriptor
	country_functional	usb_cdc_country_functional_desc
	network_terminal	usb_cdc_network_terminal_desc
	dmm			usb_cdc_dmm_desc
	mdlm			usb_cdc_mdlm_desc
	mdlm_detail		usb_cdc_mdlm_detail_desc
	obex			usb_cdc_obex_desc
	ncm			usb_cdc_ncm_desc
	mbim			usb_cdc_mbim_desc
	mbim_extended		usb_cdc_mbim_extended_desc
] [varlen]

usb_cdc_header_desc {
	bLength			len[parent, int8]
	bDescriptorType		const[USB_DT_CS_INTERFACE, int8]
	bDescriptorSubType	const[USB_CDC_HEADER_TYPE, int8]

	bcdCDC			int16
} [packed]

usb_cdc_call_mgmt_descriptor {
	bLength			len[parent, int8]
	bDescriptorType		const[USB_DT_CS_INTERFACE, int8]
	bDescriptorSubType	const[USB_CDC_CALL_MANAGEMENT_TYPE, int8]

	bmCapabilities		flags[usb_cdc_call_mgmt_caps, int8]
	bDataInterface		int8
} [packed]

usb_cdc_call_mgmt_caps = USB_CDC_CALL_MGMT_CAP_CALL_MGMT, USB_CDC_CALL_MGMT_CAP_DATA_INTF

usb_cdc_acm_descriptor {
	bLength			len[parent, int8]
	bDescriptorType		const[USB_DT_CS_INTERFACE, int8]
	bDescriptorSubType	const[USB_CDC_ACM_TYPE, int8]

	bmCapabilities		flags[usb_cdc_acm_caps, int8]
} [packed]

usb_cdc_acm_caps = USB_CDC_COMM_FEATURE, USB_CDC_CAP_LINE, USB_CDC_CAP_BRK, USB_CDC_CAP_NOTIFY

type usb_cdc_union_desc_t[MASTER, SLAVE] {
	bLength			len[parent, int8]
	bDescriptorType		const[USB_DT_CS_INTERFACE, int8]
	bDescriptorSubType	const[USB_CDC_UNION_TYPE, int8]

	bMasterInterface0	const[MASTER, int8]
	bSlaveInterface0	const[SLAVE, int8]
	slave_interfaces	array[int8, 0:6]
} [packed]

usb_cdc_country_functional_desc {
	bLength			len[parent, int8]
	bDescriptorType		const[USB_DT_CS_INTERFACE, int8]
	bDescriptorSubType	const[USB_CDC_COUNTRY_TYPE, int8]

	iCountryCodeRelDate	int8
	wCountyCode0		int16
	country_codes		array[int16, 0:6]
} [packed]

usb_cdc_network_terminal_desc {
	bLength			len[parent, int8]
	bDescriptorType		const[USB_DT_CS_INTERFACE, int8]
	bDescriptorSubType	const[USB_CDC_NETWORK_TERMINAL_TYPE, int8]

	bEntityId		int8
	iName			int8
	bChannelIndex		int8
	bPhysicalInterface	int8
} [packed]

usb_cdc_ether_desc {
	bLength			len[parent, int8]
	bDescriptorType		const[USB_DT_CS_INTERFACE, int8]
	bDescriptorSubType	const[USB_CDC_ETHERNET_TYPE, int8]

	iMACAddress		const[1, int8]
	bmEthernetStatistics	int32
	wMaxSegmentSize		int16
	wNumberMCFilters	int16
	bNumberPowerFilters	int8
} [packed]

usb_cdc_dmm_desc {
	bLength			len[parent, int8]
	bDescriptorType		const[USB_DT_CS_INTERFACE, int8]
	bDescriptorSubType	const[USB_CDC_DMM_TYPE, int8]

	bcdVersion		int16
	wMaxCommand		int16
} [packed]

usb_cdc_mdlm_desc {
	bLength			len[parent, int8]
	bDescriptorType		const[USB_DT_CS_INTERFACE, int8]
	bDescriptorSubType	const[USB_CDC_MDLM_TYPE, int8]

	bcdVersion		int16
	bGUID			usb_cdc_ecm_mbm_guid
} [packed]

# https://elixir.bootlin.com/linux/v5.2.7/source/drivers/net/usb/cdc_ether.c#L61
usb_cdc_ecm_mbm_guid {
	id0	const[0x14f5e048ba817a3, int64]
	id1	const[0x2a397ecbffc007a6, int64]
} [packed]

usb_cdc_mdlm_detail_desc {
	bLength			len[parent, int8]
	bDescriptorType		const[USB_DT_CS_INTERFACE, int8]
	bDescriptorSubType	const[USB_CDC_MDLM_DETAIL_TYPE, int8]

	bGuidDescriptorType	int8
	bDetailData		array[int8]
} [packed]

usb_cdc_obex_desc {
	bLength			len[parent, int8]
	bDescriptorType		const[USB_DT_CS_INTERFACE, int8]
	bDescriptorSubType	const[USB_CDC_OBEX_TYPE, int8]

	bcdVersion		int16
} [packed]

usb_cdc_ncm_desc {
	bLength			len[parent, int8]
	bDescriptorType		const[USB_DT_CS_INTERFACE, int8]
	bDescriptorSubType	const[USB_CDC_NCM_TYPE, int8]

	bcdNcmVersion		int16
	bmNetworkCapabilities	int8
} [packed]

usb_cdc_mbim_desc {
	bLength			len[parent, int8]
	bDescriptorType		const[USB_DT_CS_INTERFACE, int8]
	bDescriptorSubType	const[USB_CDC_MBIM_TYPE, int8]

	bcdMBIMVersion		int16
	wMaxControlMessage	int16
	bNumberFilters		int8
	bMaxFilterSize		int8
	wMaxSegmentSize		int16
	bmNetworkCapabilities	int8
} [packed]

usb_cdc_mbim_extended_desc {
	bLength				len[parent, int8]
	bDescriptorType			const[USB_DT_CS_INTERFACE, int8]
	bDescriptorSubType		const[USB_CDC_MBIM_EXTENDED_TYPE, int8]

	bcdMBIMExtendedVersion		int16
	bMaxOutstandingCommandMessages	int8
	wMTU				int16
} [packed]

vusb_descriptors_cdc_ecm {
	len		len[parent, int32]
	generic		ptr[in, vusb_descriptor_generic]

# https://elixir.bootlin.com/linux/v5.2.7/source/drivers/net/usb/usbnet.c#L147
	USB_DT_STRING	ptr[in, vusb_descriptor_t[USB_TYPE_STANDARD, USB_DT_STRING, usb_string_descriptor_t[usb_cdc_ecm_mac]]]
} [packed]

usb_cdc_ecm_mac {
# This is a UTF16 encoded string "424242424242".
	data0	const[0x3400320034003200, int64be]
	data1	const[0x3400320034003200, int64be]
	data2	const[0x3400320034003200, int64be]
} [packed]

vusb_responses_cdc_ecm {
	len				len[parent, int32]
	generic				ptr[in, vusb_response_generic]

	USB_REQ_GET_INTERFACE		ptr[in, vusb_response_t[USB_TYPE_STANDARD, USB_REQ_GET_INTERFACE, int8]]
	USB_REQ_GET_CONFIGURATION	ptr[in, vusb_response_t[USB_TYPE_STANDARD, USB_REQ_GET_CONFIGURATION, int8]]
} [packed]

# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
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# CDC NCM class specific descriptions.
# CDC NCM is based on CDC ECM, so some of the descriptions are reused.
# https://www.usb.org/document-library/network-control-model-devices-specification-v10-and-errata-and-adopters-agreement
# https://elixir.bootlin.com/linux/latest/source/drivers/net/usb/cdc_ncm.c
# https://elixir.bootlin.com/linux/latest/source/drivers/net/usb/usbnet.c
# https://elixir.bootlin.com/linux/latest/source/drivers/usb/gadget/legacy/ncm.c
# https://elixir.bootlin.com/linux/latest/source/drivers/usb/gadget/function/f_ncm.c

usb_device_descriptor_cdc_ncm {
	inner	usb_device_descriptor_t[USB_CLASS_COMM, 0, 0, 0x525, 0xa4a1, 64, array[usb_config_descriptor_cdc_ncm, 1]]
} [packed]

usb_config_descriptor_cdc_ncm {
	inner	usb_config_descriptor_t[const[1, int8], const[2, int8], flags[usb_config_attributes, int8], usb_interface_descriptors_cdc_ncm]
} [packed]

usb_interface_descriptors_cdc_ncm {
	control		usb_interface_descriptor_consts_t[0, CDC_NCM_COMM_ALTSETTING_NCM, 1, USB_CLASS_COMM, USB_CDC_SUBCLASS_NCM, USB_CDC_PROTO_NONE, usb_cdc_header_ncm, usb_endpoint_descriptor_cdc_ecm_notify]
	data_nop	usb_interface_descriptor_consts_t[1, 0, 0, USB_CLASS_COMM, USB_CDC_SUBCLASS_NCM, USB_CDC_PROTO_NONE, void, void]
	data		usb_interface_descriptor_consts_t[1, CDC_NCM_DATA_ALTSETTING_NCM, 2, USB_CLASS_COMM, USB_CDC_SUBCLASS_NCM, USB_CDC_PROTO_NONE, void, usb_endpoint_descriptors_cdc_ncm_data]
} [packed]

usb_endpoint_descriptors_cdc_ncm_data {
	in	usb_endpoint_descriptor_cdc_ecm_in
	out	usb_endpoint_descriptor_cdc_ecm_out
} [packed]

# https://elixir.bootlin.com/linux/v5.2.7/source/drivers/usb/core/message.c#L2137
# https://elixir.bootlin.com/linux/v5.2.7/source/drivers/net/usb/cdc_ncm.c#L798
usb_cdc_header_ncm {
	union	usb_cdc_union_desc_t[0, 1]
	header	usb_cdc_header_desc
	ether	usb_cdc_ether_desc
	ncm	usb_cdc_ncm_desc

	other	array[usb_cdc_header_ncm_other, 0:6]
} [packed]

usb_cdc_header_ncm_other [
	call_mgmt		usb_cdc_call_mgmt_descriptor
	acm			usb_cdc_acm_descriptor
	country_functional	usb_cdc_country_functional_desc
	network_terminal	usb_cdc_network_terminal_desc
	dmm			usb_cdc_dmm_desc
	mdlm			usb_cdc_mdlm_desc
	mdlm_detail		usb_cdc_mdlm_detail_desc
	obex			usb_cdc_obex_desc
	mbim			usb_cdc_mbim_desc
	mbim_extended		usb_cdc_mbim_extended_desc
] [varlen]

vusb_descriptors_cdc_ncm {
	len		len[parent, int32]
	generic		ptr[in, vusb_descriptor_generic]

# https://elixir.bootlin.com/linux/v5.2.7/source/drivers/net/usb/usbnet.c#L147
	USB_DT_STRING	ptr[in, vusb_descriptor_t[USB_TYPE_STANDARD, USB_DT_STRING, usb_string_descriptor_t[usb_cdc_ecm_mac]]]
} [packed]

vusb_responses_cdc_ncm {
	len				len[parent, int32]
	generic				ptr[in, vusb_response_generic]

	USB_REQ_GET_INTERFACE		ptr[in, vusb_response_t[USB_TYPE_STANDARD, USB_REQ_GET_INTERFACE, int8]]
	USB_REQ_GET_CONFIGURATION	ptr[in, vusb_response_t[USB_TYPE_STANDARD, USB_REQ_GET_CONFIGURATION, int8]]

	USB_CDC_GET_NTB_PARAMETERS	ptr[in, vusb_response_t[USB_TYPE_CLASS, USB_CDC_GET_NTB_PARAMETERS, usb_cdc_ncm_ntb_parameters]]
	USB_CDC_GET_NTB_INPUT_SIZE	ptr[in, vusb_response_t[USB_TYPE_CLASS, USB_CDC_GET_NTB_INPUT_SIZE, int32]]
	USB_CDC_GET_NTB_FORMAT		ptr[in, vusb_response_t[USB_TYPE_CLASS, USB_CDC_GET_NTB_FORMAT, int16[0:1]]]
	USB_CDC_GET_MAX_DATAGRAM_SIZE	ptr[in, vusb_response_t[USB_TYPE_CLASS, USB_CDC_GET_MAX_DATAGRAM_SIZE, int16]]
	USB_CDC_GET_CRC_MODE		ptr[in, vusb_response_t[USB_TYPE_CLASS, USB_CDC_GET_CRC_MODE, int16[0:1]]]
} [packed]

usb_cdc_ncm_ntb_parameters {
	wLength			int16
	bmNtbFormatsSupported	int16
	dwNtbInMaxSize		int32
	wNdpInDivisor		int16
	wNdpInPayloadRemainder	int16
	wNdpInAlignment		int16
	wPadding1		int16
	dwNtbOutMaxSize		int32
	wNdpOutDivisor		int16
	wNdpOutPayloadRemainder	int16
	wNdpOutAlignment	int16
	wNtbOutMaxDatagrams	int16
} [packed]

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# UAC1 device class specific descriptions.
# https://www.usb.org/sites/default/files/audio10.pdf
# https://elixir.bootlin.com/linux/latest/source/drivers/usb/gadget/legacy/audio.c
# https://elixir.bootlin.com/linux/latest/source/drivers/usb/gadget/function/f_uac1.c
# https://elixir.bootlin.com/linux/latest/source/drivers/usb/gadget/function/f_uac1_legacy.c
# https://elixir.bootlin.com/linux/latest/source/include/uapi/linux/usb/audio.h

# TODO: find out which /dev/ file are created by connected UAC1 devices.

usb_device_descriptor_uac1 {
	inner	usb_device_descriptor_t[0, 0, 0, 0x1d6b, 0x101, 64, array[usb_config_descriptor_uac1, 1]]
} [packed]

usb_config_descriptor_uac1 {
	inner	usb_config_descriptor_t[const[1, int8], const[3, int8], flags[usb_config_attributes, int8], usb_interface_descriptors_uac1]
} [packed]

# TODO: optional interrupt endpoint for control interface.
usb_interface_descriptors_uac1 {
	control		usb_interface_descriptor_consts_t[0, 0, 0, USB_CLASS_AUDIO, USB_SUBCLASS_AUDIOCONTROL, 0, uac_control_iface_extra_descriptors, void]
	as_out_alt_0	usb_interface_descriptor_consts_t[1, 0, 0, USB_CLASS_AUDIO, USB_SUBCLASS_AUDIOSTREAMING, 0, void, void]
	as_out_alt_1	usb_interface_descriptor_consts_t[1, 1, 1, USB_CLASS_AUDIO, USB_SUBCLASS_AUDIOSTREAMING, 0, uac_as_iface_extra_descriptors, uac_as_out_endpoint_descriptor]
	as_in_alt_0	usb_interface_descriptor_consts_t[2, 0, 0, USB_CLASS_AUDIO, USB_SUBCLASS_AUDIOSTREAMING, 0, void, void]
	as_in_alt_1	usb_interface_descriptor_consts_t[2, 1, 1, USB_CLASS_AUDIO, USB_SUBCLASS_AUDIOSTREAMING, 0, uac_as_iface_extra_descriptors, uac_as_in_endpoint_descriptor]
} [packed]

# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #

# UAC uses IDs to make it possible for terminals and units to refer to each other.
# We don't have a way to describe this, so just use a limited number of ids.
type uac_id int8[1:6]

uac_control_iface_extra_descriptors {
	header	uac1_ac_header_descriptor_2
	others	array[uac_control_iface_extra_descriptor, 0:6]
} [packed]

uac_as_iface_extra_descriptors {
	others	array[uac_as_iface_extra_descriptor, 0:6]
} [packed]

uac_control_iface_extra_descriptor [
	input_terminal	uac_input_terminal_descriptor
	output_terminal	uac1_output_terminal_descriptor
	mixer_unit	uac_mixer_unit_descriptor
	selector_unit	uac_selector_unit_descriptor
	feature_unit	uac_feature_unit_descriptor
	processing_unit	uac_processing_unit_descriptor
	extension_unit	uac_extension_unit_descriptor
] [varlen]

uac_as_iface_extra_descriptor [
	as_header			uac1_as_header_descriptor
	format_type_i_continuous	uac_format_type_i_continuous_descriptor
	format_type_i_discrete		uac_format_type_i_discrete_descriptor
	format_type_ii_discrete		uac_format_type_ii_discrete_descriptor
] [varlen]

define F_AUDIO_NUM_INTERFACES	2
define UAC_DT_AC_HEADER_LENGTH	UAC_DT_AC_HEADER_SIZE(F_AUDIO_NUM_INTERFACES)

uac1_ac_header_descriptor_2 {
	bLength			const[UAC_DT_AC_HEADER_LENGTH, int8]
	bDescriptorType		const[USB_DT_CS_INTERFACE, int8]
	bDescriptorSubType	const[UAC_HEADER, int8]

	bcdADC			int16
	wTotalLength		int8
	bInCollection		const[F_AUDIO_NUM_INTERFACES, int8]

# These must match interfaces numbers.
	baInterfaceNr0		const[1, int8]
	baInterfaceNr1		const[2, int8]
} [packed]

uac_input_terminal_descriptor {
	bLength			len[parent, int8]
	bDescriptorType		const[USB_DT_CS_INTERFACE, int8]
	bDescriptorSubType	const[UAC_INPUT_TERMINAL, int8]

	bTerminalID		uac_id
	wTerminalType		flags[uac_input_terminal_types, int16]
	bAssocTerminal		uac_id
	bNrChannels		int8
	wChannelConfig		int16
	iChannelNames		int8
	iTerminal		int8
} [packed]

uac_input_terminal_types = UAC_TERMINAL_UNDEFINED, UAC_TERMINAL_STREAMING, UAC_TERMINAL_VENDOR_SPEC, UAC_INPUT_TERMINAL_UNDEFINED, UAC_INPUT_TERMINAL_MICROPHONE, UAC_INPUT_TERMINAL_DESKTOP_MICROPHONE, UAC_INPUT_TERMINAL_PERSONAL_MICROPHONE, UAC_INPUT_TERMINAL_OMNI_DIR_MICROPHONE, UAC_INPUT_TERMINAL_MICROPHONE_ARRAY, UAC_INPUT_TERMINAL_PROC_MICROPHONE_ARRAY

uac1_output_terminal_descriptor {
	bLength			len[parent, int8]
	bDescriptorType		const[USB_DT_CS_INTERFACE, int8]
	bDescriptorSubType	const[UAC_OUTPUT_TERMINAL, int8]

	bTerminalID		uac_id
	wTerminalType		flags[uac_output_terminal_types, int16]
	bAssocTerminal		uac_id
	bSourceID		uac_id
	iTerminal		int8
} [packed]

uac_output_terminal_types = UAC_TERMINAL_UNDEFINED, UAC_TERMINAL_STREAMING, UAC_TERMINAL_VENDOR_SPEC, UAC_OUTPUT_TERMINAL_UNDEFINED, UAC_OUTPUT_TERMINAL_SPEAKER, UAC_OUTPUT_TERMINAL_HEADPHONES, UAC_OUTPUT_TERMINAL_HEAD_MOUNTED_DISPLAY_AUDIO, UAC_OUTPUT_TERMINAL_DESKTOP_SPEAKER, UAC_OUTPUT_TERMINAL_ROOM_SPEAKER, UAC_OUTPUT_TERMINAL_COMMUNICATION_SPEAKER, UAC_OUTPUT_TERMINAL_LOW_FREQ_EFFECTS_SPEAKER

uac_mixer_unit_descriptor {
	bLength			len[parent, int8]
	bDescriptorType		const[USB_DT_CS_INTERFACE, int8]
	bDescriptorSubType	const[UAC_MIXER_UNIT, int8]

	bUnitID			uac_id
	bNrInPins		int8
	baSourceID		array[int8, 0:6]
} [packed]

uac_selector_unit_descriptor {
	bLength			len[parent, int8]
	bDescriptorType		const[USB_DT_CS_INTERFACE, int8]
	bDescriptorSubType	const[UAC_SELECTOR_UNIT, int8]

	bUnitID			uac_id
	bNrInPins		int8
	baSourceID		array[int8, 0:6]
} [packed]

uac_feature_unit_descriptor {
	bLength			len[parent, int8]
	bDescriptorType		const[USB_DT_CS_INTERFACE, int8]
	bDescriptorSubType	const[UAC_FEATURE_UNIT, int8]

	bUnitID			uac_id
	bSourceID		uac_id
	bControlSize		len[bmaControls, int8]
	bmaControls		array[flags[uac_feature_unit_controls, int16], 1:6]
	iFeature		int8
} [packed]

uac_feature_unit_controls = UAC_FU_MUTE, UAC_FU_VOLUME, UAC_FU_BASS, UAC_FU_MID, UAC_FU_TREBLE, UAC_FU_GRAPHIC_EQUALIZER, UAC_FU_AUTOMATIC_GAIN, UAC_FU_DELAY, UAC_FU_BASS_BOOST, UAC_FU_LOUDNESS

uac_processing_unit_descriptor {
	bLength			len[parent, int8]
	bDescriptorType		const[USB_DT_CS_INTERFACE, int8]
	bDescriptorSubType	const[UAC1_PROCESSING_UNIT, int8]

	bUnitID			uac_id
	wProcessType		flags[uac_processing_unit_types, int16]
	bNrInPins		int8
	baSourceID		array[int8, 0:6]
} [packed]

uac_processing_unit_types = UAC_PROCESS_UNDEFINED, UAC_PROCESS_UP_DOWNMIX, UAC_PROCESS_DOLBY_PROLOGIC, UAC_PROCESS_STEREO_EXTENDER, UAC_PROCESS_REVERB, UAC_PROCESS_CHORUS, UAC_PROCESS_DYN_RANGE_COMP

uac_extension_unit_descriptor {
	bLength			len[parent, int8]
	bDescriptorType		const[USB_DT_CS_INTERFACE, int8]
	bDescriptorSubType	const[UAC1_EXTENSION_UNIT, int8]

	bUnitID			uac_id
	wProcessType		int16
	bNrInPins		int8
	baSourceID		array[int8, 0:6]
} [packed]

uac1_as_header_descriptor {
	bLength			len[parent, int8]
	bDescriptorType		const[USB_DT_CS_INTERFACE, int8]
	bDescriptorSubType	const[UAC_AS_GENERAL, int8]

	bTerminalLink		int8
	bDelay			int8
	wFormatTag		flags[uac_format_types, int16]
} [packed]

uac_format_types = UAC_FORMAT_TYPE_I_UNDEFINED, UAC_FORMAT_TYPE_I_PCM, UAC_FORMAT_TYPE_I_PCM8, UAC_FORMAT_TYPE_I_IEEE_FLOAT, UAC_FORMAT_TYPE_I_ALAW, UAC_FORMAT_TYPE_I_MULAW, UAC_FORMAT_TYPE_II_MPEG, UAC_FORMAT_TYPE_II_AC3

uac_format_type_i_continuous_descriptor {
	bLength			len[parent, int8]
	bDescriptorType		const[USB_DT_CS_INTERFACE, int8]
	bDescriptorSubType	const[UAC_FORMAT_TYPE, int8]

	bFormatType		const[UAC_FORMAT_TYPE_I, int8]
	bNrChannels		int8
	bSubframeSize		int8[1:4]
	bBitResolution		int8
	bSamFreqType		int8
	tLowerSamFreq		array[int8, 0:3]
	tUpperSamFreq		array[int8, 0:3]
} [packed]

uac_format_type_i_discrete_descriptor {
	bLength			len[parent, int8]
	bDescriptorType		const[USB_DT_CS_INTERFACE, int8]
	bDescriptorSubType	const[UAC_FORMAT_TYPE, int8]

	bFormatType		const[UAC_FORMAT_TYPE_I, int8]
	bNrChannels		int8
	bSubframeSize		int8[1:4]
	bBitResolution		int8
	bSamFreqType		int8
	tSamFreq		array[int8, 0:9]
} [packed]

uac_format_type_ii_discrete_descriptor {
	bLength			len[parent, int8]
	bDescriptorType		const[USB_DT_CS_INTERFACE, int8]
	bDescriptorSubType	const[UAC_FORMAT_TYPE, int8]

	bFormatType		const[UAC_FORMAT_TYPE_II, int8]
	wMaxBitRate		int16
	wSamplesPerFrame	int16
	bSamFreqType		int8
	tSamFreq		array[int8, 0:9]
} [packed]

# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #

uac_as_out_endpoint_descriptor {
	inner	usb_endpoint_descriptor_t[const[USB_ENDPOINT_UAC1_AS_OUT_ADDRESS, int8], const[USB_ENDPOINT_UAC1_AS_ATTRIBUTES, int8], uac_iso_endpoint_descriptor]
} [packed]

uac_as_in_endpoint_descriptor {
	inner	usb_endpoint_descriptor_t[const[USB_ENDPOINT_UAC1_AS_IN_ADDRESS, int8], const[USB_ENDPOINT_UAC1_AS_ATTRIBUTES, int8], uac_iso_endpoint_descriptor]
} [packed]

define USB_ENDPOINT_UAC1_AS_OUT_ADDRESS	(1 | USB_DIR_OUT)
define USB_ENDPOINT_UAC1_AS_IN_ADDRESS	(2 | USB_DIR_IN)
define USB_ENDPOINT_UAC1_AS_ATTRIBUTES	(USB_ENDPOINT_SYNC_ADAPTIVE | USB_ENDPOINT_XFER_ISOC)

uac_iso_endpoint_descriptor {
	bLength			len[parent, int8]
	bDescriptorType		const[USB_DT_CS_ENDPOINT, int8]
	bDescriptorSubType	const[UAC_EP_GENERAL, int8]

	bmAttributes		flags[uac_iso_ep_attributes, int8]
	bLockDelayUnits		int8
	wLockDelay		int16
} [packed]

uac_iso_ep_attributes = UAC_EP_CS_ATTR_SAMPLE_RATE, UAC_EP_CS_ATTR_PITCH_CONTROL, UAC_EP_CS_ATTR_FILL_MAX

# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #

vusb_descriptors_uac1 {
	len		len[parent, int32]
	generic		ptr[in, vusb_descriptor_generic]

	USB_DT_STRING	ptr[in, vusb_descriptor_t[USB_TYPE_STANDARD, USB_DT_STRING, usb_string_descriptor]]
} [packed]

vusb_responses_uac1 {
	len				len[parent, int32]
	generic				ptr[in, vusb_response_generic]

	USB_REQ_GET_INTERFACE		ptr[in, vusb_response_t[USB_TYPE_STANDARD, USB_REQ_GET_INTERFACE, int8]]
	USB_REQ_GET_CONFIGURATION	ptr[in, vusb_response_t[USB_TYPE_STANDARD, USB_REQ_GET_CONFIGURATION, int8]]

	audio_UAC_GET_CUR		ptr[in, vusb_response_t[USB_TYPE_CLASS, UAC_GET_CUR, array[int8, 1:3]]]
	audio_UAC_GET_MIN		ptr[in, vusb_response_t[USB_TYPE_CLASS, UAC_GET_MIN, array[int8, 1:3]]]
	audio_UAC_GET_MAX		ptr[in, vusb_response_t[USB_TYPE_CLASS, UAC_GET_MAX, array[int8, 1:3]]]
	audio_UAC_GET_RES		ptr[in, vusb_response_t[USB_TYPE_CLASS, UAC_GET_RES, array[int8, 1:4]]]
	audio_UAC_GET_MEM		ptr[in, vusb_response_t[USB_TYPE_CLASS, UAC_GET_MEM, array[int8, 3]]]
} [packed]

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# TODO: MIDI, UAC2, UAC3
# https://www.usb.org/sites/default/files/midi10.pdf
# https://elixir.bootlin.com/linux/latest/source/drivers/usb/gadget/function/f_midi.c
# https://elixir.bootlin.com/linux/latest/source/include/linux/usb/audio-v2.h

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