linux_dsm_epyc7002/tools/bpf/bpftool/main.h
Andrii Nakryiko 985ead416d bpftool: Add skeleton codegen command
Add `bpftool gen skeleton` command, which takes in compiled BPF .o object file
and dumps a BPF skeleton struct and related code to work with that skeleton.
Skeleton itself is tailored to a specific structure of provided BPF object
file, containing accessors (just plain struct fields) for every map and
program, as well as dedicated space for bpf_links. If BPF program is using
global variables, corresponding structure definitions of compatible memory
layout are emitted as well, making it possible to initialize and subsequently
read/update global variables values using simple and clear C syntax for
accessing fields. This skeleton majorly improves usability of
opening/loading/attaching of BPF object, as well as interacting with it
throughout the lifetime of loaded BPF object.

Generated skeleton struct has the following structure:

struct <object-name> {
	/* used by libbpf's skeleton API */
	struct bpf_object_skeleton *skeleton;
	/* bpf_object for libbpf APIs */
	struct bpf_object *obj;
	struct {
		/* for every defined map in BPF object: */
		struct bpf_map *<map-name>;
	} maps;
	struct {
		/* for every program in BPF object: */
		struct bpf_program *<program-name>;
	} progs;
	struct {
		/* for every program in BPF object: */
		struct bpf_link *<program-name>;
	} links;
	/* for every present global data section: */
	struct <object-name>__<one of bss, data, or rodata> {
		/* memory layout of corresponding data section,
		 * with every defined variable represented as a struct field
		 * with exactly the same type, but without const/volatile
		 * modifiers, e.g.:
		 */
		 int *my_var_1;
		 ...
	} *<one of bss, data, or rodata>;
};

This provides great usability improvements:
- no need to look up maps and programs by name, instead just
  my_obj->maps.my_map or my_obj->progs.my_prog would give necessary
  bpf_map/bpf_program pointers, which user can pass to existing libbpf APIs;
- pre-defined places for bpf_links, which will be automatically populated for
  program types that libbpf knows how to attach automatically (currently
  tracepoints, kprobe/kretprobe, raw tracepoint and tracing programs). On
  tearing down skeleton, all active bpf_links will be destroyed (meaning BPF
  programs will be detached, if they are attached). For cases in which libbpf
  doesn't know how to auto-attach BPF program, user can manually create link
  after loading skeleton and they will be auto-detached on skeleton
  destruction:

	my_obj->links.my_fancy_prog = bpf_program__attach_cgroup_whatever(
		my_obj->progs.my_fancy_prog, <whatever extra param);

- it's extremely easy and convenient to work with global data from userspace
  now. Both for read-only and read/write variables, it's possible to
  pre-initialize them before skeleton is loaded:

	skel = my_obj__open(raw_embed_data);
	my_obj->rodata->my_var = 123;
	my_obj__load(skel); /* 123 will be initialization value for my_var */

  After load, if kernel supports mmap() for BPF arrays, user can still read
  (and write for .bss and .data) variables values, but at that point it will
  be directly mmap()-ed to BPF array, backing global variables. This allows to
  seamlessly exchange data with BPF side. From userspace program's POV, all
  the pointers and memory contents stay the same, but mapped kernel memory
  changes to point to created map.
  If kernel doesn't yet support mmap() for BPF arrays, it's still possible to
  use those data section structs to pre-initialize .bss, .data, and .rodata,
  but after load their pointers will be reset to NULL, allowing user code to
  gracefully handle this condition, if necessary.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20191214014341.3442258-14-andriin@fb.com
2019-12-15 15:58:05 -08:00

230 lines
7.1 KiB
C

/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) */
/* Copyright (C) 2017-2018 Netronome Systems, Inc. */
#ifndef __BPF_TOOL_H
#define __BPF_TOOL_H
/* BFD and kernel.h both define GCC_VERSION, differently */
#undef GCC_VERSION
#include <stdbool.h>
#include <stdio.h>
#include <linux/bpf.h>
#include <linux/compiler.h>
#include <linux/kernel.h>
#include <linux/hashtable.h>
#include <tools/libc_compat.h>
#include "json_writer.h"
#define ptr_to_u64(ptr) ((__u64)(unsigned long)(ptr))
#define NEXT_ARG() ({ argc--; argv++; if (argc < 0) usage(); })
#define NEXT_ARGP() ({ (*argc)--; (*argv)++; if (*argc < 0) usage(); })
#define BAD_ARG() ({ p_err("what is '%s'?", *argv); -1; })
#define GET_ARG() ({ argc--; *argv++; })
#define REQ_ARGS(cnt) \
({ \
int _cnt = (cnt); \
bool _res; \
\
if (argc < _cnt) { \
p_err("'%s' needs at least %d arguments, %d found", \
argv[-1], _cnt, argc); \
_res = false; \
} else { \
_res = true; \
} \
_res; \
})
#define ERR_MAX_LEN 1024
#define BPF_TAG_FMT "%02hhx%02hhx%02hhx%02hhx%02hhx%02hhx%02hhx%02hhx"
#define HELP_SPEC_PROGRAM \
"PROG := { id PROG_ID | pinned FILE | tag PROG_TAG | name PROG_NAME }"
#define HELP_SPEC_OPTIONS \
"OPTIONS := { {-j|--json} [{-p|--pretty}] | {-f|--bpffs} |\n" \
"\t {-m|--mapcompat} | {-n|--nomount} }"
#define HELP_SPEC_MAP \
"MAP := { id MAP_ID | pinned FILE | name MAP_NAME }"
static const char * const prog_type_name[] = {
[BPF_PROG_TYPE_UNSPEC] = "unspec",
[BPF_PROG_TYPE_SOCKET_FILTER] = "socket_filter",
[BPF_PROG_TYPE_KPROBE] = "kprobe",
[BPF_PROG_TYPE_SCHED_CLS] = "sched_cls",
[BPF_PROG_TYPE_SCHED_ACT] = "sched_act",
[BPF_PROG_TYPE_TRACEPOINT] = "tracepoint",
[BPF_PROG_TYPE_XDP] = "xdp",
[BPF_PROG_TYPE_PERF_EVENT] = "perf_event",
[BPF_PROG_TYPE_CGROUP_SKB] = "cgroup_skb",
[BPF_PROG_TYPE_CGROUP_SOCK] = "cgroup_sock",
[BPF_PROG_TYPE_LWT_IN] = "lwt_in",
[BPF_PROG_TYPE_LWT_OUT] = "lwt_out",
[BPF_PROG_TYPE_LWT_XMIT] = "lwt_xmit",
[BPF_PROG_TYPE_SOCK_OPS] = "sock_ops",
[BPF_PROG_TYPE_SK_SKB] = "sk_skb",
[BPF_PROG_TYPE_CGROUP_DEVICE] = "cgroup_device",
[BPF_PROG_TYPE_SK_MSG] = "sk_msg",
[BPF_PROG_TYPE_RAW_TRACEPOINT] = "raw_tracepoint",
[BPF_PROG_TYPE_CGROUP_SOCK_ADDR] = "cgroup_sock_addr",
[BPF_PROG_TYPE_LWT_SEG6LOCAL] = "lwt_seg6local",
[BPF_PROG_TYPE_LIRC_MODE2] = "lirc_mode2",
[BPF_PROG_TYPE_SK_REUSEPORT] = "sk_reuseport",
[BPF_PROG_TYPE_FLOW_DISSECTOR] = "flow_dissector",
[BPF_PROG_TYPE_CGROUP_SYSCTL] = "cgroup_sysctl",
[BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE] = "raw_tracepoint_writable",
[BPF_PROG_TYPE_CGROUP_SOCKOPT] = "cgroup_sockopt",
};
extern const char * const map_type_name[];
extern const size_t map_type_name_size;
enum bpf_obj_type {
BPF_OBJ_UNKNOWN,
BPF_OBJ_PROG,
BPF_OBJ_MAP,
};
extern const char *bin_name;
extern json_writer_t *json_wtr;
extern bool json_output;
extern bool show_pinned;
extern bool block_mount;
extern bool verifier_logs;
extern bool relaxed_maps;
extern struct pinned_obj_table prog_table;
extern struct pinned_obj_table map_table;
void __printf(1, 2) p_err(const char *fmt, ...);
void __printf(1, 2) p_info(const char *fmt, ...);
bool is_prefix(const char *pfx, const char *str);
int detect_common_prefix(const char *arg, ...);
void fprint_hex(FILE *f, void *arg, unsigned int n, const char *sep);
void usage(void) __noreturn;
void set_max_rlimit(void);
int mount_tracefs(const char *target);
struct pinned_obj_table {
DECLARE_HASHTABLE(table, 16);
};
struct pinned_obj {
__u32 id;
char *path;
struct hlist_node hash;
};
struct btf;
struct bpf_line_info;
int build_pinned_obj_table(struct pinned_obj_table *table,
enum bpf_obj_type type);
void delete_pinned_obj_table(struct pinned_obj_table *tab);
void print_dev_plain(__u32 ifindex, __u64 ns_dev, __u64 ns_inode);
void print_dev_json(__u32 ifindex, __u64 ns_dev, __u64 ns_inode);
struct cmd {
const char *cmd;
int (*func)(int argc, char **argv);
};
int cmd_select(const struct cmd *cmds, int argc, char **argv,
int (*help)(int argc, char **argv));
int get_fd_type(int fd);
const char *get_fd_type_name(enum bpf_obj_type type);
char *get_fdinfo(int fd, const char *key);
int open_obj_pinned(char *path, bool quiet);
int open_obj_pinned_any(char *path, enum bpf_obj_type exp_type);
int mount_bpffs_for_pin(const char *name);
int do_pin_any(int argc, char **argv, int (*get_fd_by_id)(__u32));
int do_pin_fd(int fd, const char *name);
int do_prog(int argc, char **arg);
int do_map(int argc, char **arg);
int do_event_pipe(int argc, char **argv);
int do_cgroup(int argc, char **arg);
int do_perf(int argc, char **arg);
int do_net(int argc, char **arg);
int do_tracelog(int argc, char **arg);
int do_feature(int argc, char **argv);
int do_btf(int argc, char **argv);
int do_gen(int argc, char **argv);
int parse_u32_arg(int *argc, char ***argv, __u32 *val, const char *what);
int prog_parse_fd(int *argc, char ***argv);
int map_parse_fd(int *argc, char ***argv);
int map_parse_fd_and_info(int *argc, char ***argv, void *info, __u32 *info_len);
struct bpf_prog_linfo;
#ifdef HAVE_LIBBFD_SUPPORT
void disasm_print_insn(unsigned char *image, ssize_t len, int opcodes,
const char *arch, const char *disassembler_options,
const struct btf *btf,
const struct bpf_prog_linfo *prog_linfo,
__u64 func_ksym, unsigned int func_idx,
bool linum);
int disasm_init(void);
#else
static inline
void disasm_print_insn(unsigned char *image, ssize_t len, int opcodes,
const char *arch, const char *disassembler_options,
const struct btf *btf,
const struct bpf_prog_linfo *prog_linfo,
__u64 func_ksym, unsigned int func_idx,
bool linum)
{
}
static inline int disasm_init(void)
{
p_err("No libbfd support");
return -1;
}
#endif
void print_data_json(uint8_t *data, size_t len);
void print_hex_data_json(uint8_t *data, size_t len);
unsigned int get_page_size(void);
unsigned int get_possible_cpus(void);
const char *
ifindex_to_bfd_params(__u32 ifindex, __u64 ns_dev, __u64 ns_ino,
const char **opt);
struct btf_dumper {
const struct btf *btf;
json_writer_t *jw;
bool is_plain_text;
};
/* btf_dumper_type - print data along with type information
* @d: an instance containing context for dumping types
* @type_id: index in btf->types array. this points to the type to be dumped
* @data: pointer the actual data, i.e. the values to be printed
*
* Returns zero on success and negative error code otherwise
*/
int btf_dumper_type(const struct btf_dumper *d, __u32 type_id,
const void *data);
void btf_dumper_type_only(const struct btf *btf, __u32 func_type_id,
char *func_only, int size);
void btf_dump_linfo_plain(const struct btf *btf,
const struct bpf_line_info *linfo,
const char *prefix, bool linum);
void btf_dump_linfo_json(const struct btf *btf,
const struct bpf_line_info *linfo, bool linum);
struct nlattr;
struct ifinfomsg;
struct tcmsg;
int do_xdp_dump(struct ifinfomsg *ifinfo, struct nlattr **tb);
int do_filter_dump(struct tcmsg *ifinfo, struct nlattr **tb, const char *kind,
const char *devname, int ifindex);
#endif