tools/lib/bpf/libbpf.h

   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