hid_bpf_helpers.h

  1/* SPDX-License-Identifier: GPL-2.0-only */
  2/* Copyright (c) 2022 Benjamin Tissoires
  3 */
  4
  5#ifndef __HID_BPF_HELPERS_H
  6#define __HID_BPF_HELPERS_H
  7
  8/* "undefine" structs and enums in vmlinux.h, because we "override" them below */
  9#define bpf_wq bpf_wq___not_used
 10#define hid_bpf_ctx hid_bpf_ctx___not_used
 11#define hid_bpf_ops hid_bpf_ops___not_used
 12#define hid_device hid_device___not_used
 13#define hid_report_type hid_report_type___not_used
 14#define hid_class_request hid_class_request___not_used
 15#define hid_bpf_attach_flags hid_bpf_attach_flags___not_used
 16#define HID_INPUT_REPORT         HID_INPUT_REPORT___not_used
 17#define HID_OUTPUT_REPORT        HID_OUTPUT_REPORT___not_used
 18#define HID_FEATURE_REPORT       HID_FEATURE_REPORT___not_used
 19#define HID_REPORT_TYPES         HID_REPORT_TYPES___not_used
 20#define HID_REQ_GET_REPORT       HID_REQ_GET_REPORT___not_used
 21#define HID_REQ_GET_IDLE         HID_REQ_GET_IDLE___not_used
 22#define HID_REQ_GET_PROTOCOL     HID_REQ_GET_PROTOCOL___not_used
 23#define HID_REQ_SET_REPORT       HID_REQ_SET_REPORT___not_used
 24#define HID_REQ_SET_IDLE         HID_REQ_SET_IDLE___not_used
 25#define HID_REQ_SET_PROTOCOL     HID_REQ_SET_PROTOCOL___not_used
 26
 27/* do not define kfunc through vmlinux.h as this messes up our custom hack */
 28#define BPF_NO_KFUNC_PROTOTYPES
 29
 30#include "vmlinux.h"
 31
 32#undef bpf_wq
 33#undef hid_bpf_ctx
 34#undef hid_bpf_ops
 35#undef hid_device
 36#undef hid_report_type
 37#undef hid_class_request
 38#undef hid_bpf_attach_flags
 39#undef HID_INPUT_REPORT
 40#undef HID_OUTPUT_REPORT
 41#undef HID_FEATURE_REPORT
 42#undef HID_REPORT_TYPES
 43#undef HID_REQ_GET_REPORT
 44#undef HID_REQ_GET_IDLE
 45#undef HID_REQ_GET_PROTOCOL
 46#undef HID_REQ_SET_REPORT
 47#undef HID_REQ_SET_IDLE
 48#undef HID_REQ_SET_PROTOCOL
 49
 50#include <bpf/bpf_helpers.h>
 51#include <bpf/bpf_tracing.h>
 52#include <linux/const.h>
 53
 54enum hid_report_type {
 55	HID_INPUT_REPORT		= 0,
 56	HID_OUTPUT_REPORT		= 1,
 57	HID_FEATURE_REPORT		= 2,
 58
 59	HID_REPORT_TYPES,
 60};
 61
 62struct hid_device {
 63	unsigned int id;
 64} __attribute__((preserve_access_index));
 65
 66struct bpf_wq {
 67	__u64 __opaque[2];
 68};
 69
 70struct hid_bpf_ctx {
 71	struct hid_device *hid;
 72	__u32 allocated_size;
 73	union {
 74		__s32 retval;
 75		__s32 size;
 76	};
 77} __attribute__((preserve_access_index));
 78
 79enum hid_class_request {
 80	HID_REQ_GET_REPORT		= 0x01,
 81	HID_REQ_GET_IDLE		= 0x02,
 82	HID_REQ_GET_PROTOCOL		= 0x03,
 83	HID_REQ_SET_REPORT		= 0x09,
 84	HID_REQ_SET_IDLE		= 0x0A,
 85	HID_REQ_SET_PROTOCOL		= 0x0B,
 86};
 87
 88struct hid_bpf_ops {
 89	int			hid_id;
 90	u32			flags;
 91	struct list_head	list;
 92	int (*hid_device_event)(struct hid_bpf_ctx *ctx, enum hid_report_type report_type,
 93				u64 source);
 94	int (*hid_rdesc_fixup)(struct hid_bpf_ctx *ctx);
 95	int (*hid_hw_request)(struct hid_bpf_ctx *ctx, unsigned char reportnum,
 96			       enum hid_report_type rtype, enum hid_class_request reqtype,
 97			       u64 source);
 98	int (*hid_hw_output_report)(struct hid_bpf_ctx *ctx, u64 source);
 99	struct hid_device *hdev;
100};
101
102#ifndef BPF_F_BEFORE
103#define BPF_F_BEFORE (1U << 3)
104#endif
105
106/* following are kfuncs exported by HID for HID-BPF */
107extern __u8 *hid_bpf_get_data(struct hid_bpf_ctx *ctx,
108			      unsigned int offset,
109			      const size_t __sz) __weak __ksym;
110extern struct hid_bpf_ctx *hid_bpf_allocate_context(unsigned int hid_id) __weak __ksym;
111extern void hid_bpf_release_context(struct hid_bpf_ctx *ctx) __weak __ksym;
112extern int hid_bpf_hw_request(struct hid_bpf_ctx *ctx,
113			      __u8 *data,
114			      size_t buf__sz,
115			      enum hid_report_type type,
116			      enum hid_class_request reqtype) __weak __ksym;
117extern int hid_bpf_hw_output_report(struct hid_bpf_ctx *ctx,
118				    __u8 *buf, size_t buf__sz) __weak __ksym;
119extern int hid_bpf_input_report(struct hid_bpf_ctx *ctx,
120				enum hid_report_type type,
121				__u8 *data,
122				size_t buf__sz) __weak __ksym;
123extern int hid_bpf_try_input_report(struct hid_bpf_ctx *ctx,
124				    enum hid_report_type type,
125				    __u8 *data,
126				    size_t buf__sz) __weak __ksym;
127
128/* bpf_wq implementation */
129extern int bpf_wq_init(struct bpf_wq *wq, void *p__map, unsigned int flags) __weak __ksym;
130extern int bpf_wq_start(struct bpf_wq *wq, unsigned int flags) __weak __ksym;
131extern int bpf_wq_set_callback_impl(struct bpf_wq *wq,
132		int (callback_fn)(void *map, int *key, void *wq),
133		unsigned int flags__k, void *aux__ign) __weak __ksym;
134#define bpf_wq_set_callback(timer, cb, flags) \
135	bpf_wq_set_callback_impl(timer, cb, flags, NULL)
136
137#endif /* __HID_BPF_HELPERS_H */