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Wang Nan1b76c132015-07-01 02:13:51 +00001/*
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
Wang Nan1a5e3fb2015-07-01 02:13:53 +000011#include <stdio.h>
Wang Nanaa9b1ac2015-07-01 02:14:08 +000012#include <stdbool.h>
Wang Nan6371ca32015-11-06 13:49:37 +000013#include <linux/err.h>
14
15enum 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 */
22 LIBBPF_ERRNO__ENDIAN, /* Endian missmatch */
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
32int libbpf_strerror(int err, char *buf, size_t size);
Wang Nan1a5e3fb2015-07-01 02:13:53 +000033
Wang Nanb3f59d62015-07-01 02:13:52 +000034/*
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 */
39typedef int (*libbpf_print_fn_t)(const char *, ...)
40 __attribute__((format(printf, 1, 2)));
41
42void libbpf_set_print(libbpf_print_fn_t warn,
43 libbpf_print_fn_t info,
44 libbpf_print_fn_t debug);
45
Wang Nan1a5e3fb2015-07-01 02:13:53 +000046/* Hide internal to user */
47struct bpf_object;
48
49struct bpf_object *bpf_object__open(const char *path);
Wang Nan6c956392015-07-01 02:13:54 +000050struct bpf_object *bpf_object__open_buffer(void *obj_buf,
Wang Nanacf860a2015-08-27 02:30:55 +000051 size_t obj_buf_sz,
52 const char *name);
Wang Nan1a5e3fb2015-07-01 02:13:53 +000053void bpf_object__close(struct bpf_object *object);
54
Wang Nan52d33522015-07-01 02:14:04 +000055/* Load/unload object into/from kernel */
56int bpf_object__load(struct bpf_object *obj);
57int bpf_object__unload(struct bpf_object *obj);
Wang Nanacf860a2015-08-27 02:30:55 +000058const char *bpf_object__get_name(struct bpf_object *obj);
Wang Nan45825d82015-11-06 13:49:38 +000059unsigned int bpf_object__get_kversion(struct bpf_object *obj);
Wang Nan52d33522015-07-01 02:14:04 +000060
Wang Nan9a208ef2015-07-01 02:14:10 +000061struct 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
Wang Nanaa9b1ac2015-07-01 02:14:08 +000068/* Accessors of bpf_program. */
69struct bpf_program;
70struct 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
78typedef void (*bpf_program_clear_priv_t)(struct bpf_program *,
79 void *);
80
81int bpf_program__set_private(struct bpf_program *prog, void *priv,
82 bpf_program_clear_priv_t clear_priv);
83
84int bpf_program__get_private(struct bpf_program *prog,
85 void **ppriv);
86
Namhyung Kim715f8db2015-11-03 20:21:05 +090087const char *bpf_program__title(struct bpf_program *prog, bool needs_copy);
Wang Nanaa9b1ac2015-07-01 02:14:08 +000088
89int bpf_program__fd(struct bpf_program *prog);
90
Wang Nanb5805632015-11-16 12:10:09 +000091struct bpf_insn;
92
93/*
94 * Libbpf allows callers to adjust BPF programs before being loaded
95 * into kernel. One program in an object file can be transform into
96 * multiple variants to be attached to different code.
97 *
98 * bpf_program_prep_t, bpf_program__set_prep and bpf_program__nth_fd
99 * are APIs for this propose.
100 *
101 * - bpf_program_prep_t:
102 * It defines 'preprocessor', which is a caller defined function
103 * passed to libbpf through bpf_program__set_prep(), and will be
104 * called before program is loaded. The processor should adjust
105 * the program one time for each instances according to the number
106 * passed to it.
107 *
108 * - bpf_program__set_prep:
109 * Attachs a preprocessor to a BPF program. The number of instances
110 * whould be created is also passed through this function.
111 *
112 * - bpf_program__nth_fd:
113 * After the program is loaded, get resuling fds from bpf program for
114 * each instances.
115 *
116 * If bpf_program__set_prep() is not used, the program whould be loaded
117 * without adjustment during bpf_object__load(). The program has only
118 * one instance. In this case bpf_program__fd(prog) is equal to
119 * bpf_program__nth_fd(prog, 0).
120 */
121
122struct bpf_prog_prep_result {
123 /*
124 * If not NULL, load new instruction array.
125 * If set to NULL, don't load this instance.
126 */
127 struct bpf_insn *new_insn_ptr;
128 int new_insn_cnt;
129
130 /* If not NULL, result fd is set to it */
131 int *pfd;
132};
133
134/*
135 * Parameters of bpf_program_prep_t:
136 * - prog: The bpf_program being loaded.
137 * - n: Index of instance being generated.
138 * - insns: BPF instructions array.
139 * - insns_cnt:Number of instructions in insns.
140 * - res: Output parameter, result of transformation.
141 *
142 * Return value:
143 * - Zero: pre-processing success.
144 * - Non-zero: pre-processing, stop loading.
145 */
146typedef int (*bpf_program_prep_t)(struct bpf_program *prog, int n,
147 struct bpf_insn *insns, int insns_cnt,
148 struct bpf_prog_prep_result *res);
149
150int bpf_program__set_prep(struct bpf_program *prog, int nr_instance,
151 bpf_program_prep_t prep);
152
153int bpf_program__nth_fd(struct bpf_program *prog, int n);
154
Wang Nan34090912015-07-01 02:14:02 +0000155/*
156 * We don't need __attribute__((packed)) now since it is
157 * unnecessary for 'bpf_map_def' because they are all aligned.
158 * In addition, using it will trigger -Wpacked warning message,
159 * and will be treated as an error due to -Werror.
160 */
161struct bpf_map_def {
162 unsigned int type;
163 unsigned int key_size;
164 unsigned int value_size;
165 unsigned int max_entries;
166};
167
Wang Nan9d759a92015-11-27 08:47:35 +0000168/*
169 * There is another 'struct bpf_map' in include/linux/map.h. However,
170 * it is not a uapi header so no need to consider name clash.
171 */
172struct bpf_map;
Wang Nan561bbcc2015-11-27 08:47:36 +0000173struct bpf_map *
174bpf_object__get_map_by_name(struct bpf_object *obj, const char *name);
Wang Nan9d759a92015-11-27 08:47:35 +0000175
176struct bpf_map *
177bpf_map__next(struct bpf_map *map, struct bpf_object *obj);
178#define bpf_map__for_each(pos, obj) \
179 for ((pos) = bpf_map__next(NULL, (obj)); \
180 (pos) != NULL; \
181 (pos) = bpf_map__next((pos), (obj)))
182
183int bpf_map__get_fd(struct bpf_map *map);
184int bpf_map__get_def(struct bpf_map *map, struct bpf_map_def *pdef);
Wang Nan561bbcc2015-11-27 08:47:36 +0000185const char *bpf_map__get_name(struct bpf_map *map);
Wang Nan9d759a92015-11-27 08:47:35 +0000186
187typedef void (*bpf_map_clear_priv_t)(struct bpf_map *, void *);
188int bpf_map__set_private(struct bpf_map *map, void *priv,
189 bpf_map_clear_priv_t clear_priv);
190int bpf_map__get_private(struct bpf_map *map, void **ppriv);
191
Wang Nan1b76c132015-07-01 02:13:51 +0000192#endif