[linux-2.6-block.git] / tools / lib / bpf / libbpf.h

/*
 * 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 mismatch */
	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__name(struct bpf_object *obj);
unsigned int bpf_object__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_priv(struct bpf_program *prog, void *priv,
			  bpf_program_clear_priv_t clear_priv);

void *bpf_program__priv(struct bpf_program *prog);

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__find_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__fd(struct bpf_map *map);
const struct bpf_map_def *bpf_map__def(struct bpf_map *map);
const char *bpf_map__name(struct bpf_map *map);

typedef void (*bpf_map_clear_priv_t)(struct bpf_map *, void *);
int bpf_map__set_priv(struct bpf_map *map, void *priv,
		      bpf_map_clear_priv_t clear_priv);
void *bpf_map__priv(struct bpf_map *map);

#endif
Commit	Line	Data
1b76c13e WN	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	#ifndef __BPF_LIBBPF_H
	9	#define __BPF_LIBBPF_H
	10
1a5e3fb1	11	#include <stdio.h>
aa9b1ac3	12	#include <stdbool.h>
6371ca3b WN	13	#include <linux/err.h>
	14
	15	enum libbpf_errno {
	16	__LIBBPF_ERRNO__START = 4000,
	17
	18	/* Something wrong in libelf */
	19	LIBBPF_ERRNO__LIBELF = __LIBBPF_ERRNO__START,
	20	LIBBPF_ERRNO__FORMAT, /* BPF object format invalid */
	21	LIBBPF_ERRNO__KVERSION, /* Incorrect or no 'version' section */
de8a63bd	22	LIBBPF_ERRNO__ENDIAN, /* Endian mismatch */
6371ca3b WN	23	LIBBPF_ERRNO__INTERNAL, /* Internal error in libbpf */
	24	LIBBPF_ERRNO__RELOC, /* Relocation failed */
	25	LIBBPF_ERRNO__LOAD, /* Load program failure for unknown reason */
	26	LIBBPF_ERRNO__VERIFY, /* Kernel verifier blocks program loading */
	27	LIBBPF_ERRNO__PROG2BIG, /* Program too big */
	28	LIBBPF_ERRNO__KVER, /* Incorrect kernel version */
	29	__LIBBPF_ERRNO__END,
	30	};
	31
	32	int libbpf_strerror(int err, char *buf, size_t size);
1a5e3fb1	33
b3f59d66 WN	34	/*
	35	* In include/linux/compiler-gcc.h, __printf is defined. However
	36	* it should be better if libbpf.h doesn't depend on Linux header file.
	37	* So instead of __printf, here we use gcc attribute directly.
	38	*/
	39	typedef int (libbpf_print_fn_t)(const char , ...)
	40	__attribute__((format(printf, 1, 2)));
	41
	42	void libbpf_set_print(libbpf_print_fn_t warn,
	43	libbpf_print_fn_t info,
	44	libbpf_print_fn_t debug);
	45
1a5e3fb1 WN	46	/* Hide internal to user */
	47	struct bpf_object;
	48
	49	struct bpf_object bpf_object__open(const char path);
6c956392	50	struct bpf_object bpf_object__open_buffer(void obj_buf,
acf860ae WN	51	size_t obj_buf_sz,
acf860ae WN	52	const char *name);
1a5e3fb1 WN	53	void bpf_object__close(struct bpf_object *object);
1a5e3fb1 WN	54
52d3352e WN	55	/* Load/unload object into/from kernel */
	56	int bpf_object__load(struct bpf_object *obj);
	57	int bpf_object__unload(struct bpf_object *obj);
a7fe0450 ACM	58	const char bpf_object__name(struct bpf_object obj);
a7fe0450 ACM	59	unsigned int bpf_object__kversion(struct bpf_object *obj);
52d3352e	60
9a208eff WN	61	struct bpf_object bpf_object__next(struct bpf_object prev);
	62	#define bpf_object__for_each_safe(pos, tmp) \
	63	for ((pos) = bpf_object__next(NULL), \
	64	(tmp) = bpf_object__next(pos); \
	65	(pos) != NULL; \
	66	(pos) = (tmp), (tmp) = bpf_object__next(tmp))
	67
aa9b1ac3 WN	68	/* Accessors of bpf_program. */
	69	struct bpf_program;
	70	struct bpf_program bpf_program__next(struct bpf_program prog,
	71	struct bpf_object *obj);
	72
	73	#define bpf_object__for_each_program(pos, obj) \
	74	for ((pos) = bpf_program__next(NULL, (obj)); \
	75	(pos) != NULL; \
	76	(pos) = bpf_program__next((pos), (obj)))
	77
	78	typedef void (bpf_program_clear_priv_t)(struct bpf_program ,
	79	void *);
	80
edb13ed4 ACM	81	int bpf_program__set_priv(struct bpf_program prog, void priv,
edb13ed4 ACM	82	bpf_program_clear_priv_t clear_priv);
aa9b1ac3	83
be834ffb	84	void bpf_program__priv(struct bpf_program prog);
aa9b1ac3	85
715f8db9	86	const char bpf_program__title(struct bpf_program prog, bool needs_copy);
aa9b1ac3 WN	87
	88	int bpf_program__fd(struct bpf_program *prog);
	89
b580563e WN	90	struct bpf_insn;
	91
	92	/*
	93	* Libbpf allows callers to adjust BPF programs before being loaded
	94	* into kernel. One program in an object file can be transform into
	95	* multiple variants to be attached to different code.
	96	*
	97	* bpf_program_prep_t, bpf_program__set_prep and bpf_program__nth_fd
	98	* are APIs for this propose.
	99	*
	100	* - bpf_program_prep_t:
	101	* It defines 'preprocessor', which is a caller defined function
	102	* passed to libbpf through bpf_program__set_prep(), and will be
	103	* called before program is loaded. The processor should adjust
	104	* the program one time for each instances according to the number
	105	* passed to it.
	106	*
	107	* - bpf_program__set_prep:
	108	* Attachs a preprocessor to a BPF program. The number of instances
	109	* whould be created is also passed through this function.
	110	*
	111	* - bpf_program__nth_fd:
	112	* After the program is loaded, get resuling fds from bpf program for
	113	* each instances.
	114	*
	115	* If bpf_program__set_prep() is not used, the program whould be loaded
	116	* without adjustment during bpf_object__load(). The program has only
	117	* one instance. In this case bpf_program__fd(prog) is equal to
	118	* bpf_program__nth_fd(prog, 0).
	119	*/
	120
	121	struct bpf_prog_prep_result {
	122	/*
	123	* If not NULL, load new instruction array.
	124	* If set to NULL, don't load this instance.
	125	*/
	126	struct bpf_insn *new_insn_ptr;
	127	int new_insn_cnt;
	128
	129	/* If not NULL, result fd is set to it */
	130	int *pfd;
	131	};
	132
	133	/*
	134	* Parameters of bpf_program_prep_t:
	135	* - prog: The bpf_program being loaded.
	136	* - n: Index of instance being generated.
	137	* - insns: BPF instructions array.
	138	* - insns_cnt:Number of instructions in insns.
	139	* - res: Output parameter, result of transformation.
	140	*
	141	* Return value:
	142	* - Zero: pre-processing success.
	143	* - Non-zero: pre-processing, stop loading.
	144	*/
	145	typedef int (bpf_program_prep_t)(struct bpf_program prog, int n,
	146	struct bpf_insn *insns, int insns_cnt,
	147	struct bpf_prog_prep_result *res);
	148
	149	int bpf_program__set_prep(struct bpf_program *prog, int nr_instance,
	150	bpf_program_prep_t prep);
	151
	152	int bpf_program__nth_fd(struct bpf_program *prog, int n);
	153
34090915 WN	154	/*
	155	* We don't need __attribute__((packed)) now since it is
	156	* unnecessary for 'bpf_map_def' because they are all aligned.
	157	* In addition, using it will trigger -Wpacked warning message,
	158	* and will be treated as an error due to -Werror.
	159	*/
	160	struct bpf_map_def {
	161	unsigned int type;
	162	unsigned int key_size;
	163	unsigned int value_size;
	164	unsigned int max_entries;
	165	};
	166
9d759a9b WN	167	/*
	168	* There is another 'struct bpf_map' in include/linux/map.h. However,
	169	* it is not a uapi header so no need to consider name clash.
	170	*/
	171	struct bpf_map;
561bbcca	172	struct bpf_map *
a7fe0450	173	bpf_object__find_map_by_name(struct bpf_object obj, const char name);
9d759a9b WN	174
	175	struct bpf_map *
	176	bpf_map__next(struct bpf_map map, struct bpf_object obj);
	177	#define bpf_map__for_each(pos, obj) \
	178	for ((pos) = bpf_map__next(NULL, (obj)); \
	179	(pos) != NULL; \
	180	(pos) = bpf_map__next((pos), (obj)))
	181
6e009e65	182	int bpf_map__fd(struct bpf_map *map);
53897a78	183	const struct bpf_map_def bpf_map__def(struct bpf_map map);
009ad5d5	184	const char bpf_map__name(struct bpf_map map);
9d759a9b WN	185
9d759a9b WN	186	typedef void (bpf_map_clear_priv_t)(struct bpf_map , void *);
edb13ed4 ACM	187	int bpf_map__set_priv(struct bpf_map map, void priv,
edb13ed4 ACM	188	bpf_map_clear_priv_t clear_priv);
b4cbfa56	189	void bpf_map__priv(struct bpf_map map);
9d759a9b	190
1b76c13e	191	#endif