/* SPDX-License-Identifier: GPL-2.0-only */
/* Copyright (c) 2022 Benjamin Tissoires
*/
#ifndef __HID_BPF_HELPERS_H
#define __HID_BPF_HELPERS_H
#include "vmlinux.h"
#include <bpf/bpf_helpers.h>
#include <linux/errno.h>
extern __u8 *hid_bpf_get_data(struct hid_bpf_ctx *ctx,
unsigned int offset,
const size_t __sz) __ksym;
extern struct hid_bpf_ctx *hid_bpf_allocate_context(unsigned int hid_id) __ksym;
extern void hid_bpf_release_context(struct hid_bpf_ctx *ctx) __ksym;
extern int hid_bpf_hw_request(struct hid_bpf_ctx *ctx,
__u8 *data,
size_t buf__sz,
enum hid_report_type type,
enum hid_class_request reqtype) __ksym;
#define HID_MAX_DESCRIPTOR_SIZE 4096
#define HID_IGNORE_EVENT -1
/* extracted from <linux/input.h> */
#define BUS_ANY 0x00
#define BUS_PCI 0x01
#define BUS_ISAPNP 0x02
#define BUS_USB 0x03
#define BUS_HIL 0x04
#define BUS_BLUETOOTH 0x05
#define BUS_VIRTUAL 0x06
#define BUS_ISA 0x10
#define BUS_I8042 0x11
#define BUS_XTKBD 0x12
#define BUS_RS232 0x13
#define BUS_GAMEPORT 0x14
#define BUS_PARPORT 0x15
#define BUS_AMIGA 0x16
#define BUS_ADB 0x17
#define BUS_I2C 0x18
#define BUS_HOST 0x19
#define BUS_GSC 0x1A
#define BUS_ATARI 0x1B
#define BUS_SPI 0x1C
#define BUS_RMI 0x1D
#define BUS_CEC 0x1E
#define BUS_INTEL_ISHTP 0x1F
#define BUS_AMD_SFH 0x20
/* extracted from <linux/hid.h> */
#define HID_GROUP_ANY 0x0000
#define HID_GROUP_GENERIC 0x0001
#define HID_GROUP_MULTITOUCH 0x0002
#define HID_GROUP_SENSOR_HUB 0x0003
#define HID_GROUP_MULTITOUCH_WIN_8 0x0004
#define HID_GROUP_RMI 0x0100
#define HID_GROUP_WACOM 0x0101
#define HID_GROUP_LOGITECH_DJ_DEVICE 0x0102
#define HID_GROUP_STEAM 0x0103
#define HID_GROUP_LOGITECH_27MHZ_DEVICE 0x0104
#define HID_GROUP_VIVALDI 0x0105
/* include/linux/mod_devicetable.h defines as (~0), but that gives us negative size arrays */
#define HID_VID_ANY 0x0000
#define HID_PID_ANY 0x0000
#define BIT(n) (1UL << (n))
#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
/* Helper macro to convert (foo, __LINE__) into foo134 so we can use __LINE__ for
* field/variable names
*/
#define COMBINE1(X, Y) X ## Y
#define COMBINE(X, Y) COMBINE1(X, Y)
/* Macro magic:
* __uint(foo, 123) creates a int (*foo)[1234]
*
* We use that macro to declare an anonymous struct with several
* fields, each is the declaration of an pointer to an array of size
* bus/group/vid/pid. (Because it's a pointer to such an array, actual storage
* would be sizeof(pointer) rather than sizeof(array). Not that we ever
* instantiate it anyway).
*
* This is only used for BTF introspection, we can later check "what size
* is the bus array" in the introspection data and thus extract the bus ID
* again.
*
* And we use the __LINE__ to give each of our structs a unique name so the
* BPF program writer doesn't have to.
*
* $ bpftool btf dump file target/bpf/HP_Elite_Presenter.bpf.o
* shows the inspection data, start by searching for .hid_bpf_config
* and working backwards from that (each entry references the type_id of the
* content).
*/
#define HID_DEVICE(b, g, ven, prod) \
struct { \
__uint(name, 0); \
__uint(bus, (b)); \
__uint(group, (g)); \
__uint(vid, (ven)); \
__uint(pid, (prod)); \
} COMBINE(_entry, __LINE__)
/* Macro magic below is to make HID_BPF_CONFIG() look like a function call that
* we can pass multiple HID_DEVICE() invocations in.
*
* For up to 16 arguments, HID_BPF_CONFIG(one, two) resolves to
*
* union {
* HID_DEVICE(...);
* HID_DEVICE(...);
* } _device_ids SEC(".hid_bpf_config")
*
*/
/* Returns the number of macro arguments, this expands
* NARGS(a, b, c) to NTH_ARG(a, b, c, 15, 14, 13, .... 4, 3, 2, 1).
* NTH_ARG always returns the 16th argument which in our case is 3.
*
* If we want more than 16 values _COUNTDOWN and _NTH_ARG both need to be
* updated.
*/
#define _NARGS(...) _NARGS1(__VA_ARGS__, _COUNTDOWN)
#define _NARGS1(...) _NTH_ARG(__VA_ARGS__)
/* Add to this if we need more than 16 args */
#define _COUNTDOWN \
15, 14, 13, 12, 11, 10, 9, 8, \
7, 6, 5, 4, 3, 2, 1, 0
/* Return the 16 argument passed in. See _NARGS above for usage. Note this is
* 1-indexed.
*/
#define _NTH_ARG( \
_1, _2, _3, _4, _5, _6, _7, _8, \
_9, _10, _11, _12, _13, _14, _15,\
N, ...) N
/* Turns EXPAND(_ARG, a, b, c) into _ARG3(a, b, c) */
#define _EXPAND(func, ...) COMBINE(func, _NARGS(__VA_ARGS__)) (__VA_ARGS__)
/* And now define all the ARG macros for each number of args we want to accept */
#define _ARG1(_1) _1;
#define _ARG2(_1, _2) _1; _2;
#define _ARG3(_1, _2, _3) _1; _2; _3;
#define _ARG4(_1, _2, _3, _4) _1; _2; _3; _4;
#define _ARG5(_1, _2, _3, _4, _5) _1; _2; _3; _4; _5;
#define _ARG6(_1, _2, _3, _4, _5, _6) _1; _2; _3; _4; _5; _6;
#define _ARG7(_1, _2, _3, _4, _5, _6, _7) _1; _2; _3; _4; _5; _6; _7;
#define _ARG8(_1, _2, _3, _4, _5, _6, _7, _8) _1; _2; _3; _4; _5; _6; _7; _8;
#define _ARG9(_1, _2, _3, _4, _5, _6, _7, _8, _9) _1; _2; _3; _4; _5; _6; _7; _8; _9;
#define _ARG10(_1, _2, _3, _4, _5, _6, _7, _8, _9, _a) _1; _2; _3; _4; _5; _6; _7; _8; _9; _a;
#define _ARG11(_1, _2, _3, _4, _5, _6, _7, _8, _9, _a, _b) _1; _2; _3; _4; _5; _6; _7; _8; _9; _a; _b;
#define _ARG12(_1, _2, _3, _4, _5, _6, _7, _8, _9, _a, _b, _c) _1; _2; _3; _4; _5; _6; _7; _8; _9; _a; _b; _c;
#define _ARG13(_1, _2, _3, _4, _5, _6, _7, _8, _9, _a, _b, _c, _d) _1; _2; _3; _4; _5; _6; _7; _8; _9; _a; _b; _c; _d;
#define _ARG14(_1, _2, _3, _4, _5, _6, _7, _8, _9, _a, _b, _c, _d, _e) _1; _2; _3; _4; _5; _6; _7; _8; _9; _a; _b; _c; _d; _e;
#define _ARG15(_1, _2, _3, _4, _5, _6, _7, _8, _9, _a, _b, _c, _d, _e, _f) _1; _2; _3; _4; _5; _6; _7; _8; _9; _a; _b; _c; _d; _e; _f;
#define HID_BPF_CONFIG(...) union { \
_EXPAND(_ARG, __VA_ARGS__) \
} _device_ids SEC(".hid_bpf_config")
#endif /* __HID_BPF_HELPERS_H */
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