1/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
  2
  3/*
  4 * Internal libbpf helpers.
  5 *
  6 * Copyright (c) 2019 Facebook
  7 */
  8
  9#ifndef __LIBBPF_LIBBPF_INTERNAL_H
 10#define __LIBBPF_LIBBPF_INTERNAL_H
 11
 12#include "libbpf.h"
 13
 14#define BTF_INFO_ENC(kind, kind_flag, vlen) \
 15	((!!(kind_flag) << 31) | ((kind) << 24) | ((vlen) & BTF_MAX_VLEN))
 16#define BTF_TYPE_ENC(name, info, size_or_type) (name), (info), (size_or_type)
 17#define BTF_INT_ENC(encoding, bits_offset, nr_bits) \
 18	((encoding) << 24 | (bits_offset) << 16 | (nr_bits))
 19#define BTF_TYPE_INT_ENC(name, encoding, bits_offset, bits, sz) \
 20	BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_INT, 0, 0), sz), \
 21	BTF_INT_ENC(encoding, bits_offset, bits)
 22#define BTF_MEMBER_ENC(name, type, bits_offset) (name), (type), (bits_offset)
 23#define BTF_PARAM_ENC(name, type) (name), (type)
 24#define BTF_VAR_SECINFO_ENC(type, offset, size) (type), (offset), (size)
 25
 26#ifndef min
 27# define min(x, y) ((x) < (y) ? (x) : (y))
 28#endif
 29#ifndef max
 30# define max(x, y) ((x) < (y) ? (y) : (x))
 31#endif
 32#ifndef offsetofend
 33# define offsetofend(TYPE, FIELD) \
 34	(offsetof(TYPE, FIELD) + sizeof(((TYPE *)0)->FIELD))
 35#endif
 36
 37/* Symbol versioning is different between static and shared library.
 38 * Properly versioned symbols are needed for shared library, but
 39 * only the symbol of the new version is needed for static library.
 40 */
 41#ifdef SHARED
 42# define COMPAT_VERSION(internal_name, api_name, version) \
 43	asm(".symver " #internal_name "," #api_name "@" #version);
 44# define DEFAULT_VERSION(internal_name, api_name, version) \
 45	asm(".symver " #internal_name "," #api_name "@@" #version);
 46#else
 47# define COMPAT_VERSION(internal_name, api_name, version)
 48# define DEFAULT_VERSION(internal_name, api_name, version) \
 49	extern typeof(internal_name) api_name \
 50	__attribute__((alias(#internal_name)));
 51#endif
 52
 53extern void libbpf_print(enum libbpf_print_level level,
 54			 const char *format, ...)
 55	__attribute__((format(printf, 2, 3)));
 56
 57#define __pr(level, fmt, ...)	\
 58do {				\
 59	libbpf_print(level, "libbpf: " fmt, ##__VA_ARGS__);	\
 60} while (0)
 61
 62#define pr_warn(fmt, ...)	__pr(LIBBPF_WARN, fmt, ##__VA_ARGS__)
 63#define pr_info(fmt, ...)	__pr(LIBBPF_INFO, fmt, ##__VA_ARGS__)
 64#define pr_debug(fmt, ...)	__pr(LIBBPF_DEBUG, fmt, ##__VA_ARGS__)
 65
 66static inline bool libbpf_validate_opts(const char *opts,
 67					size_t opts_sz, size_t user_sz,
 68					const char *type_name)
 69{
 70	if (user_sz < sizeof(size_t)) {
 71		pr_warn("%s size (%zu) is too small\n", type_name, user_sz);
 72		return false;
 73	}
 74	if (user_sz > opts_sz) {
 75		size_t i;
 76
 77		for (i = opts_sz; i < user_sz; i++) {
 78			if (opts[i]) {
 79				pr_warn("%s has non-zero extra bytes\n",
 80					type_name);
 81				return false;
 82			}
 83		}
 84	}
 85	return true;
 86}
 87
 88#define OPTS_VALID(opts, type)						      \
 89	(!(opts) || libbpf_validate_opts((const char *)opts,		      \
 90					 offsetofend(struct type,	      \
 91						     type##__last_field),     \
 92					 (opts)->sz, #type))
 93#define OPTS_HAS(opts, field) \
 94	((opts) && opts->sz >= offsetofend(typeof(*(opts)), field))
 95#define OPTS_GET(opts, field, fallback_value) \
 96	(OPTS_HAS(opts, field) ? (opts)->field : fallback_value)
 97
 98int parse_cpu_mask_str(const char *s, bool **mask, int *mask_sz);
 99int parse_cpu_mask_file(const char *fcpu, bool **mask, int *mask_sz);
100int libbpf__load_raw_btf(const char *raw_types, size_t types_len,
101			 const char *str_sec, size_t str_len);
102
103int bpf_object__section_size(const struct bpf_object *obj, const char *name,
104			     __u32 *size);
105int bpf_object__variable_offset(const struct bpf_object *obj, const char *name,
106				__u32 *off);
107
108struct nlattr;
109typedef int (*libbpf_dump_nlmsg_t)(void *cookie, void *msg, struct nlattr **tb);
110int libbpf_netlink_open(unsigned int *nl_pid);
111int libbpf_nl_get_link(int sock, unsigned int nl_pid,
112		       libbpf_dump_nlmsg_t dump_link_nlmsg, void *cookie);
113int libbpf_nl_get_class(int sock, unsigned int nl_pid, int ifindex,
114			libbpf_dump_nlmsg_t dump_class_nlmsg, void *cookie);
115int libbpf_nl_get_qdisc(int sock, unsigned int nl_pid, int ifindex,
116			libbpf_dump_nlmsg_t dump_qdisc_nlmsg, void *cookie);
117int libbpf_nl_get_filter(int sock, unsigned int nl_pid, int ifindex, int handle,
118			 libbpf_dump_nlmsg_t dump_filter_nlmsg, void *cookie);
119
120struct btf_ext_info {
121	/*
122	 * info points to the individual info section (e.g. func_info and
123	 * line_info) from the .BTF.ext. It does not include the __u32 rec_size.
124	 */
125	void *info;
126	__u32 rec_size;
127	__u32 len;
128};
129
130#define for_each_btf_ext_sec(seg, sec)					\
131	for (sec = (seg)->info;						\
132	     (void *)sec < (seg)->info + (seg)->len;			\
133	     sec = (void *)sec + sizeof(struct btf_ext_info_sec) +	\
134		   (seg)->rec_size * sec->num_info)
135
136#define for_each_btf_ext_rec(seg, sec, i, rec)				\
137	for (i = 0, rec = (void *)&(sec)->data;				\
138	     i < (sec)->num_info;					\
139	     i++, rec = (void *)rec + (seg)->rec_size)
140
141struct btf_ext {
142	union {
143		struct btf_ext_header *hdr;
144		void *data;
145	};
146	struct btf_ext_info func_info;
147	struct btf_ext_info line_info;
148	struct btf_ext_info field_reloc_info;
149	__u32 data_size;
150};
151
152struct btf_ext_info_sec {
153	__u32	sec_name_off;
154	__u32	num_info;
155	/* Followed by num_info * record_size number of bytes */
156	__u8	data[];
157};
158
159/* The minimum bpf_func_info checked by the loader */
160struct bpf_func_info_min {
161	__u32   insn_off;
162	__u32   type_id;
163};
164
165/* The minimum bpf_line_info checked by the loader */
166struct bpf_line_info_min {
167	__u32	insn_off;
168	__u32	file_name_off;
169	__u32	line_off;
170	__u32	line_col;
171};
172
173/* bpf_field_info_kind encodes which aspect of captured field has to be
174 * adjusted by relocations. Currently supported values are:
175 *   - BPF_FIELD_BYTE_OFFSET: field offset (in bytes);
176 *   - BPF_FIELD_EXISTS: field existence (1, if field exists; 0, otherwise);
177 */
178enum bpf_field_info_kind {
179	BPF_FIELD_BYTE_OFFSET = 0,	/* field byte offset */
180	BPF_FIELD_BYTE_SIZE = 1,
181	BPF_FIELD_EXISTS = 2,		/* field existence in target kernel */
182	BPF_FIELD_SIGNED = 3,
183	BPF_FIELD_LSHIFT_U64 = 4,
184	BPF_FIELD_RSHIFT_U64 = 5,
185};
186
187/* The minimum bpf_field_reloc checked by the loader
188 *
189 * Field relocation captures the following data:
190 * - insn_off - instruction offset (in bytes) within a BPF program that needs
191 *   its insn->imm field to be relocated with actual field info;
192 * - type_id - BTF type ID of the "root" (containing) entity of a relocatable
193 *   field;
194 * - access_str_off - offset into corresponding .BTF string section. String
195 *   itself encodes an accessed field using a sequence of field and array
196 *   indicies, separated by colon (:). It's conceptually very close to LLVM's
197 *   getelementptr ([0]) instruction's arguments for identifying offset to 
198 *   a field.
199 *
200 * Example to provide a better feel.
201 *
202 *   struct sample {
203 *       int a;
204 *       struct {
205 *           int b[10];
206 *       };
207 *   };
208 *
209 *   struct sample *s = ...;
210 *   int x = &s->a;     // encoded as "0:0" (a is field #0)
211 *   int y = &s->b[5];  // encoded as "0:1:0:5" (anon struct is field #1, 
212 *                      // b is field #0 inside anon struct, accessing elem #5)
213 *   int z = &s[10]->b; // encoded as "10:1" (ptr is used as an array)
214 *
215 * type_id for all relocs in this example  will capture BTF type id of
216 * `struct sample`.
217 *
218 * Such relocation is emitted when using __builtin_preserve_access_index()
219 * Clang built-in, passing expression that captures field address, e.g.:
220 *
221 * bpf_probe_read(&dst, sizeof(dst),
222 *		  __builtin_preserve_access_index(&src->a.b.c));
223 *
224 * In this case Clang will emit field relocation recording necessary data to
225 * be able to find offset of embedded `a.b.c` field within `src` struct.
226 *
227 *   [0] https://llvm.org/docs/LangRef.html#getelementptr-instruction
228 */
229struct bpf_field_reloc {
230	__u32   insn_off;
231	__u32   type_id;
232	__u32   access_str_off;
233	enum bpf_field_info_kind kind;
234};
235
236#endif /* __LIBBPF_LIBBPF_INTERNAL_H */