1 /* 2 * Common eBPF ELF object loading operations. 3 * 4 * Copyright (C) 2013-2015 Alexei Starovoitov <ast@kernel.org> 5 * Copyright (C) 2015 Wang Nan <wangnan0@huawei.com> 6 * Copyright (C) 2015 Huawei Inc. 7 * 8 * This program is free software; you can redistribute it and/or 9 * modify it under the terms of the GNU Lesser General Public 10 * License as published by the Free Software Foundation; 11 * version 2.1 of the License (not later!) 12 * 13 * This program is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 * GNU Lesser General Public License for more details. 17 * 18 * You should have received a copy of the GNU Lesser General Public 19 * License along with this program; if not, see <http://www.gnu.org/licenses> 20 */ 21 #ifndef __BPF_LIBBPF_H 22 #define __BPF_LIBBPF_H 23 24 #include <stdio.h> 25 #include <stdint.h> 26 #include <stdbool.h> 27 #include <sys/types.h> // for size_t 28 29 enum libbpf_errno { 30 __LIBBPF_ERRNO__START = 4000, 31 32 /* Something wrong in libelf */ 33 LIBBPF_ERRNO__LIBELF = __LIBBPF_ERRNO__START, 34 LIBBPF_ERRNO__FORMAT, /* BPF object format invalid */ 35 LIBBPF_ERRNO__KVERSION, /* Incorrect or no 'version' section */ 36 LIBBPF_ERRNO__ENDIAN, /* Endian mismatch */ 37 LIBBPF_ERRNO__INTERNAL, /* Internal error in libbpf */ 38 LIBBPF_ERRNO__RELOC, /* Relocation failed */ 39 LIBBPF_ERRNO__LOAD, /* Load program failure for unknown reason */ 40 LIBBPF_ERRNO__VERIFY, /* Kernel verifier blocks program loading */ 41 LIBBPF_ERRNO__PROG2BIG, /* Program too big */ 42 LIBBPF_ERRNO__KVER, /* Incorrect kernel version */ 43 LIBBPF_ERRNO__PROGTYPE, /* Kernel doesn't support this program type */ 44 __LIBBPF_ERRNO__END, 45 }; 46 47 int libbpf_strerror(int err, char *buf, size_t size); 48 49 /* 50 * In include/linux/compiler-gcc.h, __printf is defined. However 51 * it should be better if libbpf.h doesn't depend on Linux header file. 52 * So instead of __printf, here we use gcc attribute directly. 53 */ 54 typedef int (*libbpf_print_fn_t)(const char *, ...) 55 __attribute__((format(printf, 1, 2))); 56 57 void libbpf_set_print(libbpf_print_fn_t warn, 58 libbpf_print_fn_t info, 59 libbpf_print_fn_t debug); 60 61 /* Hide internal to user */ 62 struct bpf_object; 63 64 struct bpf_object *bpf_object__open(const char *path); 65 struct bpf_object *bpf_object__open_buffer(void *obj_buf, 66 size_t obj_buf_sz, 67 const char *name); 68 int bpf_object__pin(struct bpf_object *object, const char *path); 69 void bpf_object__close(struct bpf_object *object); 70 71 /* Load/unload object into/from kernel */ 72 int bpf_object__load(struct bpf_object *obj); 73 int bpf_object__unload(struct bpf_object *obj); 74 const char *bpf_object__name(struct bpf_object *obj); 75 unsigned int bpf_object__kversion(struct bpf_object *obj); 76 77 struct bpf_object *bpf_object__next(struct bpf_object *prev); 78 #define bpf_object__for_each_safe(pos, tmp) \ 79 for ((pos) = bpf_object__next(NULL), \ 80 (tmp) = bpf_object__next(pos); \ 81 (pos) != NULL; \ 82 (pos) = (tmp), (tmp) = bpf_object__next(tmp)) 83 84 typedef void (*bpf_object_clear_priv_t)(struct bpf_object *, void *); 85 int bpf_object__set_priv(struct bpf_object *obj, void *priv, 86 bpf_object_clear_priv_t clear_priv); 87 void *bpf_object__priv(struct bpf_object *prog); 88 89 /* Accessors of bpf_program. */ 90 struct bpf_program; 91 struct bpf_program *bpf_program__next(struct bpf_program *prog, 92 struct bpf_object *obj); 93 94 #define bpf_object__for_each_program(pos, obj) \ 95 for ((pos) = bpf_program__next(NULL, (obj)); \ 96 (pos) != NULL; \ 97 (pos) = bpf_program__next((pos), (obj))) 98 99 typedef void (*bpf_program_clear_priv_t)(struct bpf_program *, 100 void *); 101 102 int bpf_program__set_priv(struct bpf_program *prog, void *priv, 103 bpf_program_clear_priv_t clear_priv); 104 105 void *bpf_program__priv(struct bpf_program *prog); 106 107 const char *bpf_program__title(struct bpf_program *prog, bool needs_copy); 108 109 int bpf_program__fd(struct bpf_program *prog); 110 int bpf_program__pin_instance(struct bpf_program *prog, const char *path, 111 int instance); 112 int bpf_program__pin(struct bpf_program *prog, const char *path); 113 114 struct bpf_insn; 115 116 /* 117 * Libbpf allows callers to adjust BPF programs before being loaded 118 * into kernel. One program in an object file can be transform into 119 * multiple variants to be attached to different code. 120 * 121 * bpf_program_prep_t, bpf_program__set_prep and bpf_program__nth_fd 122 * are APIs for this propose. 123 * 124 * - bpf_program_prep_t: 125 * It defines 'preprocessor', which is a caller defined function 126 * passed to libbpf through bpf_program__set_prep(), and will be 127 * called before program is loaded. The processor should adjust 128 * the program one time for each instances according to the number 129 * passed to it. 130 * 131 * - bpf_program__set_prep: 132 * Attachs a preprocessor to a BPF program. The number of instances 133 * whould be created is also passed through this function. 134 * 135 * - bpf_program__nth_fd: 136 * After the program is loaded, get resuling fds from bpf program for 137 * each instances. 138 * 139 * If bpf_program__set_prep() is not used, the program whould be loaded 140 * without adjustment during bpf_object__load(). The program has only 141 * one instance. In this case bpf_program__fd(prog) is equal to 142 * bpf_program__nth_fd(prog, 0). 143 */ 144 145 struct bpf_prog_prep_result { 146 /* 147 * If not NULL, load new instruction array. 148 * If set to NULL, don't load this instance. 149 */ 150 struct bpf_insn *new_insn_ptr; 151 int new_insn_cnt; 152 153 /* If not NULL, result fd is set to it */ 154 int *pfd; 155 }; 156 157 /* 158 * Parameters of bpf_program_prep_t: 159 * - prog: The bpf_program being loaded. 160 * - n: Index of instance being generated. 161 * - insns: BPF instructions array. 162 * - insns_cnt:Number of instructions in insns. 163 * - res: Output parameter, result of transformation. 164 * 165 * Return value: 166 * - Zero: pre-processing success. 167 * - Non-zero: pre-processing, stop loading. 168 */ 169 typedef int (*bpf_program_prep_t)(struct bpf_program *prog, int n, 170 struct bpf_insn *insns, int insns_cnt, 171 struct bpf_prog_prep_result *res); 172 173 int bpf_program__set_prep(struct bpf_program *prog, int nr_instance, 174 bpf_program_prep_t prep); 175 176 int bpf_program__nth_fd(struct bpf_program *prog, int n); 177 178 /* 179 * Adjust type of bpf program. Default is kprobe. 180 */ 181 int bpf_program__set_socket_filter(struct bpf_program *prog); 182 int bpf_program__set_tracepoint(struct bpf_program *prog); 183 int bpf_program__set_kprobe(struct bpf_program *prog); 184 int bpf_program__set_sched_cls(struct bpf_program *prog); 185 int bpf_program__set_sched_act(struct bpf_program *prog); 186 int bpf_program__set_xdp(struct bpf_program *prog); 187 int bpf_program__set_perf_event(struct bpf_program *prog); 188 189 bool bpf_program__is_socket_filter(struct bpf_program *prog); 190 bool bpf_program__is_tracepoint(struct bpf_program *prog); 191 bool bpf_program__is_kprobe(struct bpf_program *prog); 192 bool bpf_program__is_sched_cls(struct bpf_program *prog); 193 bool bpf_program__is_sched_act(struct bpf_program *prog); 194 bool bpf_program__is_xdp(struct bpf_program *prog); 195 bool bpf_program__is_perf_event(struct bpf_program *prog); 196 197 /* 198 * We don't need __attribute__((packed)) now since it is 199 * unnecessary for 'bpf_map_def' because they are all aligned. 200 * In addition, using it will trigger -Wpacked warning message, 201 * and will be treated as an error due to -Werror. 202 */ 203 struct bpf_map_def { 204 unsigned int type; 205 unsigned int key_size; 206 unsigned int value_size; 207 unsigned int max_entries; 208 }; 209 210 /* 211 * There is another 'struct bpf_map' in include/linux/map.h. However, 212 * it is not a uapi header so no need to consider name clash. 213 */ 214 struct bpf_map; 215 struct bpf_map * 216 bpf_object__find_map_by_name(struct bpf_object *obj, const char *name); 217 218 /* 219 * Get bpf_map through the offset of corresponding struct bpf_map_def 220 * in the bpf object file. 221 */ 222 struct bpf_map * 223 bpf_object__find_map_by_offset(struct bpf_object *obj, size_t offset); 224 225 struct bpf_map * 226 bpf_map__next(struct bpf_map *map, struct bpf_object *obj); 227 #define bpf_map__for_each(pos, obj) \ 228 for ((pos) = bpf_map__next(NULL, (obj)); \ 229 (pos) != NULL; \ 230 (pos) = bpf_map__next((pos), (obj))) 231 232 int bpf_map__fd(struct bpf_map *map); 233 const struct bpf_map_def *bpf_map__def(struct bpf_map *map); 234 const char *bpf_map__name(struct bpf_map *map); 235 236 typedef void (*bpf_map_clear_priv_t)(struct bpf_map *, void *); 237 int bpf_map__set_priv(struct bpf_map *map, void *priv, 238 bpf_map_clear_priv_t clear_priv); 239 void *bpf_map__priv(struct bpf_map *map); 240 int bpf_map__pin(struct bpf_map *map, const char *path); 241 242 long libbpf_get_error(const void *ptr); 243 244 #endif 245