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 #include "vmlinux.h" 9 #include <bpf/bpf_helpers.h> 10 #include <linux/errno.h> 11 12 extern __u8 *hid_bpf_get_data(struct hid_bpf_ctx *ctx, 13 unsigned int offset, 14 const size_t __sz) __ksym; 15 extern struct hid_bpf_ctx *hid_bpf_allocate_context(unsigned int hid_id) __ksym; 16 extern void hid_bpf_release_context(struct hid_bpf_ctx *ctx) __ksym; 17 extern int hid_bpf_hw_request(struct hid_bpf_ctx *ctx, 18 __u8 *data, 19 size_t buf__sz, 20 enum hid_report_type type, 21 enum hid_class_request reqtype) __ksym; 22 extern int hid_bpf_hw_output_report(struct hid_bpf_ctx *ctx, 23 __u8 *buf, size_t buf__sz) __weak __ksym; 24 extern int hid_bpf_input_report(struct hid_bpf_ctx *ctx, 25 enum hid_report_type type, 26 __u8 *data, 27 size_t buf__sz) __weak __ksym; 28 extern int hid_bpf_try_input_report(struct hid_bpf_ctx *ctx, 29 enum hid_report_type type, 30 __u8 *data, 31 size_t buf__sz) __weak __ksym; 32 33 /* bpf_wq implementation */ 34 extern int bpf_wq_init(struct bpf_wq *wq, void *p__map, unsigned int flags) __weak __ksym; 35 extern int bpf_wq_start(struct bpf_wq *wq, unsigned int flags) __weak __ksym; 36 extern int bpf_wq_set_callback_impl(struct bpf_wq *wq, 37 int (callback_fn)(void *map, int *key, void *value), 38 unsigned int flags__k, void *aux__ign) __ksym; 39 #define bpf_wq_set_callback(wq, cb, flags) \ 40 bpf_wq_set_callback_impl(wq, cb, flags, NULL) 41 42 #define HID_MAX_DESCRIPTOR_SIZE 4096 43 #define HID_IGNORE_EVENT -1 44 45 /* extracted from <linux/input.h> */ 46 #define BUS_ANY 0x00 47 #define BUS_PCI 0x01 48 #define BUS_ISAPNP 0x02 49 #define BUS_USB 0x03 50 #define BUS_HIL 0x04 51 #define BUS_BLUETOOTH 0x05 52 #define BUS_VIRTUAL 0x06 53 #define BUS_ISA 0x10 54 #define BUS_I8042 0x11 55 #define BUS_XTKBD 0x12 56 #define BUS_RS232 0x13 57 #define BUS_GAMEPORT 0x14 58 #define BUS_PARPORT 0x15 59 #define BUS_AMIGA 0x16 60 #define BUS_ADB 0x17 61 #define BUS_I2C 0x18 62 #define BUS_HOST 0x19 63 #define BUS_GSC 0x1A 64 #define BUS_ATARI 0x1B 65 #define BUS_SPI 0x1C 66 #define BUS_RMI 0x1D 67 #define BUS_CEC 0x1E 68 #define BUS_INTEL_ISHTP 0x1F 69 #define BUS_AMD_SFH 0x20 70 71 /* extracted from <linux/hid.h> */ 72 #define HID_GROUP_ANY 0x0000 73 #define HID_GROUP_GENERIC 0x0001 74 #define HID_GROUP_MULTITOUCH 0x0002 75 #define HID_GROUP_SENSOR_HUB 0x0003 76 #define HID_GROUP_MULTITOUCH_WIN_8 0x0004 77 #define HID_GROUP_RMI 0x0100 78 #define HID_GROUP_WACOM 0x0101 79 #define HID_GROUP_LOGITECH_DJ_DEVICE 0x0102 80 #define HID_GROUP_STEAM 0x0103 81 #define HID_GROUP_LOGITECH_27MHZ_DEVICE 0x0104 82 #define HID_GROUP_VIVALDI 0x0105 83 84 /* include/linux/mod_devicetable.h defines as (~0), but that gives us negative size arrays */ 85 #define HID_VID_ANY 0x0000 86 #define HID_PID_ANY 0x0000 87 88 #define BIT(n) (1UL << (n)) 89 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0])) 90 91 /* Helper macro to convert (foo, __LINE__) into foo134 so we can use __LINE__ for 92 * field/variable names 93 */ 94 #define COMBINE1(X, Y) X ## Y 95 #define COMBINE(X, Y) COMBINE1(X, Y) 96 97 /* Macro magic: 98 * __uint(foo, 123) creates a int (*foo)[1234] 99 * 100 * We use that macro to declare an anonymous struct with several 101 * fields, each is the declaration of an pointer to an array of size 102 * bus/group/vid/pid. (Because it's a pointer to such an array, actual storage 103 * would be sizeof(pointer) rather than sizeof(array). Not that we ever 104 * instantiate it anyway). 105 * 106 * This is only used for BTF introspection, we can later check "what size 107 * is the bus array" in the introspection data and thus extract the bus ID 108 * again. 109 * 110 * And we use the __LINE__ to give each of our structs a unique name so the 111 * BPF program writer doesn't have to. 112 * 113 * $ bpftool btf dump file target/bpf/HP_Elite_Presenter.bpf.o 114 * shows the inspection data, start by searching for .hid_bpf_config 115 * and working backwards from that (each entry references the type_id of the 116 * content). 117 */ 118 119 #define HID_DEVICE(b, g, ven, prod) \ 120 struct { \ 121 __uint(name, 0); \ 122 __uint(bus, (b)); \ 123 __uint(group, (g)); \ 124 __uint(vid, (ven)); \ 125 __uint(pid, (prod)); \ 126 } COMBINE(_entry, __LINE__) 127 128 /* Macro magic below is to make HID_BPF_CONFIG() look like a function call that 129 * we can pass multiple HID_DEVICE() invocations in. 130 * 131 * For up to 16 arguments, HID_BPF_CONFIG(one, two) resolves to 132 * 133 * union { 134 * HID_DEVICE(...); 135 * HID_DEVICE(...); 136 * } _device_ids SEC(".hid_bpf_config") 137 * 138 */ 139 140 /* Returns the number of macro arguments, this expands 141 * NARGS(a, b, c) to NTH_ARG(a, b, c, 15, 14, 13, .... 4, 3, 2, 1). 142 * NTH_ARG always returns the 16th argument which in our case is 3. 143 * 144 * If we want more than 16 values _COUNTDOWN and _NTH_ARG both need to be 145 * updated. 146 */ 147 #define _NARGS(...) _NARGS1(__VA_ARGS__, _COUNTDOWN) 148 #define _NARGS1(...) _NTH_ARG(__VA_ARGS__) 149 150 /* Add to this if we need more than 16 args */ 151 #define _COUNTDOWN \ 152 15, 14, 13, 12, 11, 10, 9, 8, \ 153 7, 6, 5, 4, 3, 2, 1, 0 154 155 /* Return the 16 argument passed in. See _NARGS above for usage. Note this is 156 * 1-indexed. 157 */ 158 #define _NTH_ARG( \ 159 _1, _2, _3, _4, _5, _6, _7, _8, \ 160 _9, _10, _11, _12, _13, _14, _15,\ 161 N, ...) N 162 163 /* Turns EXPAND(_ARG, a, b, c) into _ARG3(a, b, c) */ 164 #define _EXPAND(func, ...) COMBINE(func, _NARGS(__VA_ARGS__)) (__VA_ARGS__) 165 166 /* And now define all the ARG macros for each number of args we want to accept */ 167 #define _ARG1(_1) _1; 168 #define _ARG2(_1, _2) _1; _2; 169 #define _ARG3(_1, _2, _3) _1; _2; _3; 170 #define _ARG4(_1, _2, _3, _4) _1; _2; _3; _4; 171 #define _ARG5(_1, _2, _3, _4, _5) _1; _2; _3; _4; _5; 172 #define _ARG6(_1, _2, _3, _4, _5, _6) _1; _2; _3; _4; _5; _6; 173 #define _ARG7(_1, _2, _3, _4, _5, _6, _7) _1; _2; _3; _4; _5; _6; _7; 174 #define _ARG8(_1, _2, _3, _4, _5, _6, _7, _8) _1; _2; _3; _4; _5; _6; _7; _8; 175 #define _ARG9(_1, _2, _3, _4, _5, _6, _7, _8, _9) _1; _2; _3; _4; _5; _6; _7; _8; _9; 176 #define _ARG10(_1, _2, _3, _4, _5, _6, _7, _8, _9, _a) _1; _2; _3; _4; _5; _6; _7; _8; _9; _a; 177 #define _ARG11(_1, _2, _3, _4, _5, _6, _7, _8, _9, _a, _b) _1; _2; _3; _4; _5; _6; _7; _8; _9; _a; _b; 178 #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; 179 #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; 180 #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; 181 #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; 182 183 184 #define HID_BPF_CONFIG(...) union { \ 185 _EXPAND(_ARG, __VA_ARGS__) \ 186 } _device_ids SEC(".hid_bpf_config") 187 188 #endif /* __HID_BPF_HELPERS_H */ 189