summaryrefslogtreecommitdiff
path: root/tools/lib/bpf/libbpf.h
blob: cd3fd8d782c7bd8813d6b36f0378fc38ac3a370f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
/* SPDX-License-Identifier: LGPL-2.1 */

/*
 * 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.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation;
 * version 2.1 of the License (not later!)
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this program; if not,  see <http://www.gnu.org/licenses>
 */
#ifndef __BPF_LIBBPF_H
#define __BPF_LIBBPF_H

#include <stdio.h>
#include <stdint.h>
#include <stdbool.h>
#include <sys/types.h>  // for size_t
#include <linux/bpf.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__PROGTYPE,	/* Kernel doesn't support this program type */
	LIBBPF_ERRNO__WRNGPID,	/* Wrong pid in netlink message */
	LIBBPF_ERRNO__INVSEQ,	/* Invalid netlink sequence */
	__LIBBPF_ERRNO__END,
};

int libbpf_strerror(int err, char *buf, size_t size);

/*
 * __printf is defined in include/linux/compiler-gcc.h. However,
 * it would be better if libbpf.h didn't depend on Linux header files.
 * 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);
int bpf_object__pin(struct bpf_object *object, const char *path);
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);
int bpf_object__btf_fd(const 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))

typedef void (*bpf_object_clear_priv_t)(struct bpf_object *, void *);
int bpf_object__set_priv(struct bpf_object *obj, void *priv,
			 bpf_object_clear_priv_t clear_priv);
void *bpf_object__priv(struct bpf_object *prog);

/* 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);
int bpf_program__pin_instance(struct bpf_program *prog, const char *path,
			      int instance);
int bpf_program__pin(struct bpf_program *prog, const char *path);

struct bpf_insn;

/*
 * Libbpf allows callers to adjust BPF programs before being loaded
 * into kernel. One program in an object file can be transformed into
 * multiple variants to be attached to different hooks.
 *
 * bpf_program_prep_t, bpf_program__set_prep and bpf_program__nth_fd
 * form an API for this purpose.
 *
 * - bpf_program_prep_t:
 *   Defines a '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 instance according to the instance id
 *   passed to it.
 *
 * - bpf_program__set_prep:
 *   Attaches a preprocessor to a BPF program. The number of instances
 *   that should be created is also passed through this function.
 *
 * - bpf_program__nth_fd:
 *   After the program is loaded, get resulting FD of a given instance
 *   of the BPF program.
 *
 * If bpf_program__set_prep() is not used, the program would 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 written 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 error, 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);

/*
 * Adjust type of BPF program. Default is kprobe.
 */
int bpf_program__set_socket_filter(struct bpf_program *prog);
int bpf_program__set_tracepoint(struct bpf_program *prog);
int bpf_program__set_raw_tracepoint(struct bpf_program *prog);
int bpf_program__set_kprobe(struct bpf_program *prog);
int bpf_program__set_sched_cls(struct bpf_program *prog);
int bpf_program__set_sched_act(struct bpf_program *prog);
int bpf_program__set_xdp(struct bpf_program *prog);
int bpf_program__set_perf_event(struct bpf_program *prog);
void bpf_program__set_type(struct bpf_program *prog, enum bpf_prog_type type);
void bpf_program__set_expected_attach_type(struct bpf_program *prog,
					   enum bpf_attach_type type);

bool bpf_program__is_socket_filter(struct bpf_program *prog);
bool bpf_program__is_tracepoint(struct bpf_program *prog);
bool bpf_program__is_raw_tracepoint(struct bpf_program *prog);
bool bpf_program__is_kprobe(struct bpf_program *prog);
bool bpf_program__is_sched_cls(struct bpf_program *prog);
bool bpf_program__is_sched_act(struct bpf_program *prog);
bool bpf_program__is_xdp(struct bpf_program *prog);
bool bpf_program__is_perf_event(struct bpf_program *prog);

/*
 * No need for __attribute__((packed)), all members of 'bpf_map_def'
 * are all aligned.  In addition, using __attribute__((packed))
 * would trigger a -Wpacked warning message, and lead to an error
 * if -Werror is set.
 */
struct bpf_map_def {
	unsigned int type;
	unsigned int key_size;
	unsigned int value_size;
	unsigned int max_entries;
	unsigned int map_flags;
};

/*
 * The 'struct bpf_map' in include/linux/bpf.h is internal to the kernel,
 * so no need to worry about a name clash.
 */
struct bpf_map;
struct bpf_map *
bpf_object__find_map_by_name(struct bpf_object *obj, const char *name);

/*
 * Get bpf_map through the offset of corresponding struct bpf_map_def
 * in the BPF object file.
 */
struct bpf_map *
bpf_object__find_map_by_offset(struct bpf_object *obj, size_t offset);

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);
uint32_t bpf_map__btf_key_id(const struct bpf_map *map);
uint32_t bpf_map__btf_value_id(const 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);
int bpf_map__pin(struct bpf_map *map, const char *path);

long libbpf_get_error(const void *ptr);

struct bpf_prog_load_attr {
	const char *file;
	enum bpf_prog_type prog_type;
	enum bpf_attach_type expected_attach_type;
	int ifindex;
};

int bpf_prog_load_xattr(const struct bpf_prog_load_attr *attr,
			struct bpf_object **pobj, int *prog_fd);
int bpf_prog_load(const char *file, enum bpf_prog_type type,
		  struct bpf_object **pobj, int *prog_fd);

int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags);

enum bpf_perf_event_ret {
	LIBBPF_PERF_EVENT_DONE	= 0,
	LIBBPF_PERF_EVENT_ERROR	= -1,
	LIBBPF_PERF_EVENT_CONT	= -2,
};

typedef enum bpf_perf_event_ret (*bpf_perf_event_print_t)(void *event,
							  void *priv);
int bpf_perf_event_read_simple(void *mem, unsigned long size,
			       unsigned long page_size,
			       void **buf, size_t *buf_len,
			       bpf_perf_event_print_t fn, void *priv);
#endif