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/*
* Common eBPF ELF object loading operations.
*
* Copyright (C) 2013-2015 Alexei Starovoitov <ast@kernel.org>
* Copyright (C) 2015 Wang Nan <wangnan0@huawei.com>
* Copyright (C) 2015 Huawei Inc.
*/
#ifndef __BPF_LIBBPF_H
#define __BPF_LIBBPF_H
#include <stdio.h>
#include <stdbool.h>
#include <linux/err.h>
enum libbpf_errno {
__LIBBPF_ERRNO__START = 4000,
/* Something wrong in libelf */
LIBBPF_ERRNO__LIBELF = __LIBBPF_ERRNO__START,
LIBBPF_ERRNO__FORMAT, /* BPF object format invalid */
LIBBPF_ERRNO__KVERSION, /* Incorrect or no 'version' section */
LIBBPF_ERRNO__ENDIAN, /* Endian missmatch */
LIBBPF_ERRNO__INTERNAL, /* Internal error in libbpf */
LIBBPF_ERRNO__RELOC, /* Relocation failed */
LIBBPF_ERRNO__LOAD, /* Load program failure for unknown reason */
LIBBPF_ERRNO__VERIFY, /* Kernel verifier blocks program loading */
LIBBPF_ERRNO__PROG2BIG, /* Program too big */
LIBBPF_ERRNO__KVER, /* Incorrect kernel version */
__LIBBPF_ERRNO__END,
};
int libbpf_strerror(int err, char *buf, size_t size);
/*
* In include/linux/compiler-gcc.h, __printf is defined. However
* it should be better if libbpf.h doesn't depend on Linux header file.
* So instead of __printf, here we use gcc attribute directly.
*/
typedef int (*libbpf_print_fn_t)(const char *, ...)
__attribute__((format(printf, 1, 2)));
void libbpf_set_print(libbpf_print_fn_t warn,
libbpf_print_fn_t info,
libbpf_print_fn_t debug);
/* Hide internal to user */
struct bpf_object;
struct bpf_object *bpf_object__open(const char *path);
struct bpf_object *bpf_object__open_buffer(void *obj_buf,
size_t obj_buf_sz,
const char *name);
void bpf_object__close(struct bpf_object *object);
/* Load/unload object into/from kernel */
int bpf_object__load(struct bpf_object *obj);
int bpf_object__unload(struct bpf_object *obj);
const char *bpf_object__get_name(struct bpf_object *obj);
unsigned int bpf_object__get_kversion(struct bpf_object *obj);
struct bpf_object *bpf_object__next(struct bpf_object *prev);
#define bpf_object__for_each_safe(pos, tmp) \
for ((pos) = bpf_object__next(NULL), \
(tmp) = bpf_object__next(pos); \
(pos) != NULL; \
(pos) = (tmp), (tmp) = bpf_object__next(tmp))
/* Accessors of bpf_program. */
struct bpf_program;
struct bpf_program *bpf_program__next(struct bpf_program *prog,
struct bpf_object *obj);
#define bpf_object__for_each_program(pos, obj) \
for ((pos) = bpf_program__next(NULL, (obj)); \
(pos) != NULL; \
(pos) = bpf_program__next((pos), (obj)))
typedef void (*bpf_program_clear_priv_t)(struct bpf_program *,
void *);
int bpf_program__set_private(struct bpf_program *prog, void *priv,
bpf_program_clear_priv_t clear_priv);
int bpf_program__get_private(struct bpf_program *prog,
void **ppriv);
const char *bpf_program__title(struct bpf_program *prog, bool needs_copy);
int bpf_program__fd(struct bpf_program *prog);
struct bpf_insn;
/*
* Libbpf allows callers to adjust BPF programs before being loaded
* into kernel. One program in an object file can be transform into
* multiple variants to be attached to different code.
*
* bpf_program_prep_t, bpf_program__set_prep and bpf_program__nth_fd
* are APIs for this propose.
*
* - bpf_program_prep_t:
* It defines 'preprocessor', which is a caller defined function
* passed to libbpf through bpf_program__set_prep(), and will be
* called before program is loaded. The processor should adjust
* the program one time for each instances according to the number
* passed to it.
*
* - bpf_program__set_prep:
* Attachs a preprocessor to a BPF program. The number of instances
* whould be created is also passed through this function.
*
* - bpf_program__nth_fd:
* After the program is loaded, get resuling fds from bpf program for
* each instances.
*
* If bpf_program__set_prep() is not used, the program whould be loaded
* without adjustment during bpf_object__load(). The program has only
* one instance. In this case bpf_program__fd(prog) is equal to
* bpf_program__nth_fd(prog, 0).
*/
struct bpf_prog_prep_result {
/*
* If not NULL, load new instruction array.
* If set to NULL, don't load this instance.
*/
struct bpf_insn *new_insn_ptr;
int new_insn_cnt;
/* If not NULL, result fd is set to it */
int *pfd;
};
/*
* Parameters of bpf_program_prep_t:
* - prog: The bpf_program being loaded.
* - n: Index of instance being generated.
* - insns: BPF instructions array.
* - insns_cnt:Number of instructions in insns.
* - res: Output parameter, result of transformation.
*
* Return value:
* - Zero: pre-processing success.
* - Non-zero: pre-processing, stop loading.
*/
typedef int (*bpf_program_prep_t)(struct bpf_program *prog, int n,
struct bpf_insn *insns, int insns_cnt,
struct bpf_prog_prep_result *res);
int bpf_program__set_prep(struct bpf_program *prog, int nr_instance,
bpf_program_prep_t prep);
int bpf_program__nth_fd(struct bpf_program *prog, int n);
/*
* We don't need __attribute__((packed)) now since it is
* unnecessary for 'bpf_map_def' because they are all aligned.
* In addition, using it will trigger -Wpacked warning message,
* and will be treated as an error due to -Werror.
*/
struct bpf_map_def {
unsigned int type;
unsigned int key_size;
unsigned int value_size;
unsigned int max_entries;
};
/*
* There is another 'struct bpf_map' in include/linux/map.h. However,
* it is not a uapi header so no need to consider name clash.
*/
struct bpf_map;
struct bpf_map *
bpf_object__get_map_by_name(struct bpf_object *obj, const char *name);
struct bpf_map *
bpf_map__next(struct bpf_map *map, struct bpf_object *obj);
#define bpf_map__for_each(pos, obj) \
for ((pos) = bpf_map__next(NULL, (obj)); \
(pos) != NULL; \
(pos) = bpf_map__next((pos), (obj)))
int bpf_map__get_fd(struct bpf_map *map);
int bpf_map__get_def(struct bpf_map *map, struct bpf_map_def *pdef);
const char *bpf_map__get_name(struct bpf_map *map);
typedef void (*bpf_map_clear_priv_t)(struct bpf_map *, void *);
int bpf_map__set_private(struct bpf_map *map, void *priv,
bpf_map_clear_priv_t clear_priv);
int bpf_map__get_private(struct bpf_map *map, void **ppriv);
#endif
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