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linux/tools/lib/bpf/libbpf_internal.h

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/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
/*
* Internal libbpf helpers.
*
* Copyright (c) 2019 Facebook
*/
#ifndef __LIBBPF_LIBBPF_INTERNAL_H
#define __LIBBPF_LIBBPF_INTERNAL_H
#include "libbpf.h"
#define BTF_INFO_ENC(kind, kind_flag, vlen) \
((!!(kind_flag) << 31) | ((kind) << 24) | ((vlen) & BTF_MAX_VLEN))
#define BTF_TYPE_ENC(name, info, size_or_type) (name), (info), (size_or_type)
#define BTF_INT_ENC(encoding, bits_offset, nr_bits) \
((encoding) << 24 | (bits_offset) << 16 | (nr_bits))
#define BTF_TYPE_INT_ENC(name, encoding, bits_offset, bits, sz) \
BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_INT, 0, 0), sz), \
BTF_INT_ENC(encoding, bits_offset, bits)
#define BTF_MEMBER_ENC(name, type, bits_offset) (name), (type), (bits_offset)
#define BTF_PARAM_ENC(name, type) (name), (type)
#define BTF_VAR_SECINFO_ENC(type, offset, size) (type), (offset), (size)
#ifndef min
# define min(x, y) ((x) < (y) ? (x) : (y))
#endif
#ifndef max
# define max(x, y) ((x) < (y) ? (y) : (x))
#endif
#ifndef offsetofend
# define offsetofend(TYPE, FIELD) \
(offsetof(TYPE, FIELD) + sizeof(((TYPE *)0)->FIELD))
#endif
/* Symbol versioning is different between static and shared library.
* Properly versioned symbols are needed for shared library, but
* only the symbol of the new version is needed for static library.
*/
#ifdef SHARED
# define COMPAT_VERSION(internal_name, api_name, version) \
asm(".symver " #internal_name "," #api_name "@" #version);
# define DEFAULT_VERSION(internal_name, api_name, version) \
asm(".symver " #internal_name "," #api_name "@@" #version);
#else
# define COMPAT_VERSION(internal_name, api_name, version)
# define DEFAULT_VERSION(internal_name, api_name, version) \
extern typeof(internal_name) api_name \
__attribute__((alias(#internal_name)));
#endif
extern void libbpf_print(enum libbpf_print_level level,
const char *format, ...)
__attribute__((format(printf, 2, 3)));
#define __pr(level, fmt, ...) \
do { \
libbpf_print(level, "libbpf: " fmt, ##__VA_ARGS__); \
} while (0)
#define pr_warn(fmt, ...) __pr(LIBBPF_WARN, fmt, ##__VA_ARGS__)
#define pr_info(fmt, ...) __pr(LIBBPF_INFO, fmt, ##__VA_ARGS__)
#define pr_debug(fmt, ...) __pr(LIBBPF_DEBUG, fmt, ##__VA_ARGS__)
static inline bool libbpf_validate_opts(const char *opts,
size_t opts_sz, size_t user_sz,
const char *type_name)
{
if (user_sz < sizeof(size_t)) {
pr_warn("%s size (%zu) is too small\n", type_name, user_sz);
return false;
}
if (user_sz > opts_sz) {
size_t i;
for (i = opts_sz; i < user_sz; i++) {
if (opts[i]) {
pr_warn("%s has non-zero extra bytes\n",
type_name);
return false;
}
}
}
return true;
}
#define OPTS_VALID(opts, type) \
(!(opts) || libbpf_validate_opts((const char *)opts, \
offsetofend(struct type, \
type##__last_field), \
(opts)->sz, #type))
#define OPTS_HAS(opts, field) \
((opts) && opts->sz >= offsetofend(typeof(*(opts)), field))
#define OPTS_GET(opts, field, fallback_value) \
(OPTS_HAS(opts, field) ? (opts)->field : fallback_value)
int parse_cpu_mask_str(const char *s, bool **mask, int *mask_sz);
int parse_cpu_mask_file(const char *fcpu, bool **mask, int *mask_sz);
int libbpf__load_raw_btf(const char *raw_types, size_t types_len,
const char *str_sec, size_t str_len);
int bpf_object__section_size(const struct bpf_object *obj, const char *name,
__u32 *size);
int bpf_object__variable_offset(const struct bpf_object *obj, const char *name,
__u32 *off);
struct nlattr;
typedef int (*libbpf_dump_nlmsg_t)(void *cookie, void *msg, struct nlattr **tb);
int libbpf_netlink_open(unsigned int *nl_pid);
int libbpf_nl_get_link(int sock, unsigned int nl_pid,
libbpf_dump_nlmsg_t dump_link_nlmsg, void *cookie);
int libbpf_nl_get_class(int sock, unsigned int nl_pid, int ifindex,
libbpf_dump_nlmsg_t dump_class_nlmsg, void *cookie);
int libbpf_nl_get_qdisc(int sock, unsigned int nl_pid, int ifindex,
libbpf_dump_nlmsg_t dump_qdisc_nlmsg, void *cookie);
int libbpf_nl_get_filter(int sock, unsigned int nl_pid, int ifindex, int handle,
libbpf_dump_nlmsg_t dump_filter_nlmsg, void *cookie);
struct btf_ext_info {
/*
* info points to the individual info section (e.g. func_info and
* line_info) from the .BTF.ext. It does not include the __u32 rec_size.
*/
void *info;
__u32 rec_size;
__u32 len;
};
#define for_each_btf_ext_sec(seg, sec) \
for (sec = (seg)->info; \
(void *)sec < (seg)->info + (seg)->len; \
sec = (void *)sec + sizeof(struct btf_ext_info_sec) + \
(seg)->rec_size * sec->num_info)
#define for_each_btf_ext_rec(seg, sec, i, rec) \
for (i = 0, rec = (void *)&(sec)->data; \
i < (sec)->num_info; \
i++, rec = (void *)rec + (seg)->rec_size)
struct btf_ext {
union {
struct btf_ext_header *hdr;
void *data;
};
struct btf_ext_info func_info;
struct btf_ext_info line_info;
struct btf_ext_info field_reloc_info;
__u32 data_size;
};
struct btf_ext_info_sec {
__u32 sec_name_off;
__u32 num_info;
/* Followed by num_info * record_size number of bytes */
__u8 data[0];
};
/* The minimum bpf_func_info checked by the loader */
struct bpf_func_info_min {
__u32 insn_off;
__u32 type_id;
};
/* The minimum bpf_line_info checked by the loader */
struct bpf_line_info_min {
__u32 insn_off;
__u32 file_name_off;
__u32 line_off;
__u32 line_col;
};
/* bpf_field_info_kind encodes which aspect of captured field has to be
* adjusted by relocations. Currently supported values are:
* - BPF_FIELD_BYTE_OFFSET: field offset (in bytes);
* - BPF_FIELD_EXISTS: field existence (1, if field exists; 0, otherwise);
*/
enum bpf_field_info_kind {
BPF_FIELD_BYTE_OFFSET = 0, /* field byte offset */
BPF_FIELD_BYTE_SIZE = 1,
BPF_FIELD_EXISTS = 2, /* field existence in target kernel */
BPF_FIELD_SIGNED = 3,
BPF_FIELD_LSHIFT_U64 = 4,
BPF_FIELD_RSHIFT_U64 = 5,
};
/* The minimum bpf_field_reloc checked by the loader
*
* Field relocation captures the following data:
* - insn_off - instruction offset (in bytes) within a BPF program that needs
* its insn->imm field to be relocated with actual field info;
* - type_id - BTF type ID of the "root" (containing) entity of a relocatable
* field;
* - access_str_off - offset into corresponding .BTF string section. String
* itself encodes an accessed field using a sequence of field and array
* indicies, separated by colon (:). It's conceptually very close to LLVM's
* getelementptr ([0]) instruction's arguments for identifying offset to
* a field.
*
* Example to provide a better feel.
*
* struct sample {
* int a;
* struct {
* int b[10];
* };
* };
*
* struct sample *s = ...;
* int x = &s->a; // encoded as "0:0" (a is field #0)
* int y = &s->b[5]; // encoded as "0:1:0:5" (anon struct is field #1,
* // b is field #0 inside anon struct, accessing elem #5)
* int z = &s[10]->b; // encoded as "10:1" (ptr is used as an array)
*
* type_id for all relocs in this example will capture BTF type id of
* `struct sample`.
*
* Such relocation is emitted when using __builtin_preserve_access_index()
* Clang built-in, passing expression that captures field address, e.g.:
*
* bpf_probe_read(&dst, sizeof(dst),
* __builtin_preserve_access_index(&src->a.b.c));
*
* In this case Clang will emit field relocation recording necessary data to
* be able to find offset of embedded `a.b.c` field within `src` struct.
*
* [0] https://llvm.org/docs/LangRef.html#getelementptr-instruction
*/
struct bpf_field_reloc {
__u32 insn_off;
__u32 type_id;
__u32 access_str_off;
enum bpf_field_info_kind kind;
};
#endif /* __LIBBPF_LIBBPF_INTERNAL_H */
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