linux/include/linux/hid_bpf.h

/* SPDX-License-Identifier: GPL-2.0+ */

#ifndef __HID_BPF_H
#define __HID_BPF_H

#include <linux/bpf.h>
#include <linux/mutex.h>
#include <linux/srcu.h>
#include <uapi/linux/hid.h>

struct hid_device;

/*
 * The following is the user facing HID BPF API.
 *
 * Extra care should be taken when editing this part, as
 * it might break existing out of the tree bpf programs.
 */

/**
 * struct hid_bpf_ctx - User accessible data for all HID programs
 *
 * ``data`` is not directly accessible from the context. We need to issue
 * a call to hid_bpf_get_data() in order to get a pointer to that field.
 *
 * @hid: the &struct hid_device representing the device itself
 * @allocated_size: Allocated size of data.
 *
 *                  This is how much memory is available and can be requested
 *                  by the HID program.
 *                  Note that for ``HID_BPF_RDESC_FIXUP``, that memory is set to
 *                  ``4096`` (4 KB)
 * @size: Valid data in the data field.
 *
 *        Programs can get the available valid size in data by fetching this field.
 *        Programs can also change this value by returning a positive number in the
 *        program.
 *        To discard the event, return a negative error code.
 *
 *        ``size`` must always be less or equal than ``allocated_size`` (it is enforced
 *        once all BPF programs have been run).
 * @retval: Return value of the previous program.
 *
 * ``hid`` and ``allocated_size`` are read-only, ``size`` and ``retval`` are read-write.
 */
struct hid_bpf_ctx {};

/*
 * Below is HID internal
 */

#define HID_BPF_MAX_PROGS_PER_DEV
#define HID_BPF_FLAG_MASK


struct hid_report_enum;

struct hid_ops {};

extern struct hid_ops *hid_ops;

/**
 * struct hid_bpf_ops - A BPF struct_ops of callbacks allowing to attach HID-BPF
 *			programs to a HID device
 * @hid_id: the HID uniq ID to attach to. This is writeable before ``load()``, and
 *	    cannot be changed after
 * @flags: flags used while attaching the struct_ops to the device. Currently only
 *	   available value is %0 or ``BPF_F_BEFORE``.
 *	   Writeable only before ``load()``
 */
struct hid_bpf_ops {};

/* stored in each device */
struct hid_bpf {};

#ifdef CONFIG_HID_BPF
u8 *dispatch_hid_bpf_device_event(struct hid_device *hid, enum hid_report_type type, u8 *data,
				  u32 *size, int interrupt, u64 source, bool from_bpf);
int dispatch_hid_bpf_raw_requests(struct hid_device *hdev,
				  unsigned char reportnum, __u8 *buf,
				  u32 size, enum hid_report_type rtype,
				  enum hid_class_request reqtype,
				  u64 source, bool from_bpf);
int dispatch_hid_bpf_output_report(struct hid_device *hdev, __u8 *buf, u32 size,
				   u64 source, bool from_bpf);
int hid_bpf_connect_device(struct hid_device *hdev);
void hid_bpf_disconnect_device(struct hid_device *hdev);
void hid_bpf_destroy_device(struct hid_device *hid);
int hid_bpf_device_init(struct hid_device *hid);
u8 *call_hid_bpf_rdesc_fixup(struct hid_device *hdev, const u8 *rdesc, unsigned int *size);
#else /* CONFIG_HID_BPF */
static inline u8 *dispatch_hid_bpf_device_event(struct hid_device *hid, enum hid_report_type type,
						u8 *data, u32 *size, int interrupt,
						u64 source, bool from_bpf) { return data; }
static inline int dispatch_hid_bpf_raw_requests(struct hid_device *hdev,
						unsigned char reportnum, u8 *buf,
						u32 size, enum hid_report_type rtype,
						enum hid_class_request reqtype,
						u64 source, bool from_bpf) { return 0; }
static inline int dispatch_hid_bpf_output_report(struct hid_device *hdev, __u8 *buf, u32 size,
						 u64 source, bool from_bpf) { return 0; }
static inline int hid_bpf_connect_device(struct hid_device *hdev) { return 0; }
static inline void hid_bpf_disconnect_device(struct hid_device *hdev) {}
static inline void hid_bpf_destroy_device(struct hid_device *hid) {}
static inline int hid_bpf_device_init(struct hid_device *hid) { return 0; }
/*
 * This specialized allocator has to be a macro for its allocations to be
 * accounted separately (to have a separate alloc_tag). The typecast is
 * intentional to enforce typesafety.
 */
#define call_hid_bpf_rdesc_fixup

#endif /* CONFIG_HID_BPF */

#endif /* __HID_BPF_H */