mirror_iproute2/include/bpf_util.h
Hangbin Liu 503e9229b0 iproute2: add check_libbpf() and get_libbpf_version()
This patch aim to add basic checking functions for later iproute2
libbpf support.

First we add check_libbpf() in configure to see if we have bpf library
support. By default the system libbpf will be used, but static linking
against a custom libbpf version can be achieved by passing libbpf DESTDIR
to variable LIBBPF_DIR for configure.

Another variable LIBBPF_FORCE is used to control whether to build iproute2
with libbpf. If set to on, then force to build with libbpf and exit if
not available. If set to off, then force to not build with libbpf.

When dynamically linking against libbpf, we can't be sure that the
version we discovered at compile time is actually the one we are
using at runtime. This can lead to hard-to-debug errors. So we add
a new file lib/bpf_glue.c and a helper function get_libbpf_version()
to get correct libbpf version at runtime.

Signed-off-by: Hangbin Liu <haliu@redhat.com>
Signed-off-by: David Ahern <dsahern@gmail.com>
2020-11-24 22:14:02 -07:00

307 lines
7.3 KiB
C

/*
* bpf_util.h BPF common code
*
* This program is free software; you can distribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* Authors: Daniel Borkmann <daniel@iogearbox.net>
* Jiri Pirko <jiri@resnulli.us>
*/
#ifndef __BPF_UTIL__
#define __BPF_UTIL__
#include <linux/bpf.h>
#include <linux/btf.h>
#include <linux/filter.h>
#include <linux/magic.h>
#include <linux/elf-em.h>
#include <linux/if_alg.h>
#include "utils.h"
#include "bpf_scm.h"
#define BPF_ENV_UDS "TC_BPF_UDS"
#define BPF_ENV_MNT "TC_BPF_MNT"
#ifndef BPF_MAX_LOG
# define BPF_MAX_LOG 4096
#endif
#define BPF_DIR_GLOBALS "globals"
#ifndef BPF_FS_MAGIC
# define BPF_FS_MAGIC 0xcafe4a11
#endif
#define BPF_DIR_MNT "/sys/fs/bpf"
#ifndef TRACEFS_MAGIC
# define TRACEFS_MAGIC 0x74726163
#endif
#define TRACE_DIR_MNT "/sys/kernel/tracing"
#ifndef AF_ALG
# define AF_ALG 38
#endif
#ifndef EM_BPF
# define EM_BPF 247
#endif
struct bpf_cfg_ops {
void (*cbpf_cb)(void *nl, const struct sock_filter *ops, int ops_len);
void (*ebpf_cb)(void *nl, int fd, const char *annotation);
};
enum bpf_mode {
CBPF_BYTECODE,
CBPF_FILE,
EBPF_OBJECT,
EBPF_PINNED,
BPF_MODE_MAX,
};
struct bpf_cfg_in {
const char *object;
const char *section;
const char *uds;
enum bpf_prog_type type;
enum bpf_mode mode;
__u32 ifindex;
bool verbose;
int argc;
char **argv;
struct sock_filter opcodes[BPF_MAXINSNS];
union {
int n_opcodes;
int prog_fd;
};
};
/* ALU ops on registers, bpf_add|sub|...: dst_reg += src_reg */
#define BPF_ALU64_REG(OP, DST, SRC) \
((struct bpf_insn) { \
.code = BPF_ALU64 | BPF_OP(OP) | BPF_X, \
.dst_reg = DST, \
.src_reg = SRC, \
.off = 0, \
.imm = 0 })
#define BPF_ALU32_REG(OP, DST, SRC) \
((struct bpf_insn) { \
.code = BPF_ALU | BPF_OP(OP) | BPF_X, \
.dst_reg = DST, \
.src_reg = SRC, \
.off = 0, \
.imm = 0 })
/* ALU ops on immediates, bpf_add|sub|...: dst_reg += imm32 */
#define BPF_ALU64_IMM(OP, DST, IMM) \
((struct bpf_insn) { \
.code = BPF_ALU64 | BPF_OP(OP) | BPF_K, \
.dst_reg = DST, \
.src_reg = 0, \
.off = 0, \
.imm = IMM })
#define BPF_ALU32_IMM(OP, DST, IMM) \
((struct bpf_insn) { \
.code = BPF_ALU | BPF_OP(OP) | BPF_K, \
.dst_reg = DST, \
.src_reg = 0, \
.off = 0, \
.imm = IMM })
/* Short form of mov, dst_reg = src_reg */
#define BPF_MOV64_REG(DST, SRC) \
((struct bpf_insn) { \
.code = BPF_ALU64 | BPF_MOV | BPF_X, \
.dst_reg = DST, \
.src_reg = SRC, \
.off = 0, \
.imm = 0 })
#define BPF_MOV32_REG(DST, SRC) \
((struct bpf_insn) { \
.code = BPF_ALU | BPF_MOV | BPF_X, \
.dst_reg = DST, \
.src_reg = SRC, \
.off = 0, \
.imm = 0 })
/* Short form of mov, dst_reg = imm32 */
#define BPF_MOV64_IMM(DST, IMM) \
((struct bpf_insn) { \
.code = BPF_ALU64 | BPF_MOV | BPF_K, \
.dst_reg = DST, \
.src_reg = 0, \
.off = 0, \
.imm = IMM })
#define BPF_MOV32_IMM(DST, IMM) \
((struct bpf_insn) { \
.code = BPF_ALU | BPF_MOV | BPF_K, \
.dst_reg = DST, \
.src_reg = 0, \
.off = 0, \
.imm = IMM })
/* BPF_LD_IMM64 macro encodes single 'load 64-bit immediate' insn */
#define BPF_LD_IMM64(DST, IMM) \
BPF_LD_IMM64_RAW(DST, 0, IMM)
#define BPF_LD_IMM64_RAW(DST, SRC, IMM) \
((struct bpf_insn) { \
.code = BPF_LD | BPF_DW | BPF_IMM, \
.dst_reg = DST, \
.src_reg = SRC, \
.off = 0, \
.imm = (__u32) (IMM) }), \
((struct bpf_insn) { \
.code = 0, /* zero is reserved opcode */ \
.dst_reg = 0, \
.src_reg = 0, \
.off = 0, \
.imm = ((__u64) (IMM)) >> 32 })
#ifndef BPF_PSEUDO_MAP_FD
# define BPF_PSEUDO_MAP_FD 1
#endif
/* pseudo BPF_LD_IMM64 insn used to refer to process-local map_fd */
#define BPF_LD_MAP_FD(DST, MAP_FD) \
BPF_LD_IMM64_RAW(DST, BPF_PSEUDO_MAP_FD, MAP_FD)
/* Direct packet access, R0 = *(uint *) (skb->data + imm32) */
#define BPF_LD_ABS(SIZE, IMM) \
((struct bpf_insn) { \
.code = BPF_LD | BPF_SIZE(SIZE) | BPF_ABS, \
.dst_reg = 0, \
.src_reg = 0, \
.off = 0, \
.imm = IMM })
/* Memory load, dst_reg = *(uint *) (src_reg + off16) */
#define BPF_LDX_MEM(SIZE, DST, SRC, OFF) \
((struct bpf_insn) { \
.code = BPF_LDX | BPF_SIZE(SIZE) | BPF_MEM, \
.dst_reg = DST, \
.src_reg = SRC, \
.off = OFF, \
.imm = 0 })
/* Memory store, *(uint *) (dst_reg + off16) = src_reg */
#define BPF_STX_MEM(SIZE, DST, SRC, OFF) \
((struct bpf_insn) { \
.code = BPF_STX | BPF_SIZE(SIZE) | BPF_MEM, \
.dst_reg = DST, \
.src_reg = SRC, \
.off = OFF, \
.imm = 0 })
/* Memory store, *(uint *) (dst_reg + off16) = imm32 */
#define BPF_ST_MEM(SIZE, DST, OFF, IMM) \
((struct bpf_insn) { \
.code = BPF_ST | BPF_SIZE(SIZE) | BPF_MEM, \
.dst_reg = DST, \
.src_reg = 0, \
.off = OFF, \
.imm = IMM })
/* Conditional jumps against registers, if (dst_reg 'op' src_reg) goto pc + off16 */
#define BPF_JMP_REG(OP, DST, SRC, OFF) \
((struct bpf_insn) { \
.code = BPF_JMP | BPF_OP(OP) | BPF_X, \
.dst_reg = DST, \
.src_reg = SRC, \
.off = OFF, \
.imm = 0 })
/* Conditional jumps against immediates, if (dst_reg 'op' imm32) goto pc + off16 */
#define BPF_JMP_IMM(OP, DST, IMM, OFF) \
((struct bpf_insn) { \
.code = BPF_JMP | BPF_OP(OP) | BPF_K, \
.dst_reg = DST, \
.src_reg = 0, \
.off = OFF, \
.imm = IMM })
/* Raw code statement block */
#define BPF_RAW_INSN(CODE, DST, SRC, OFF, IMM) \
((struct bpf_insn) { \
.code = CODE, \
.dst_reg = DST, \
.src_reg = SRC, \
.off = OFF, \
.imm = IMM })
/* Program exit */
#define BPF_EXIT_INSN() \
((struct bpf_insn) { \
.code = BPF_JMP | BPF_EXIT, \
.dst_reg = 0, \
.src_reg = 0, \
.off = 0, \
.imm = 0 })
int bpf_parse_common(struct bpf_cfg_in *cfg, const struct bpf_cfg_ops *ops);
int bpf_load_common(struct bpf_cfg_in *cfg, const struct bpf_cfg_ops *ops,
void *nl);
int bpf_parse_and_load_common(struct bpf_cfg_in *cfg,
const struct bpf_cfg_ops *ops, void *nl);
const char *bpf_prog_to_default_section(enum bpf_prog_type type);
int bpf_graft_map(const char *map_path, uint32_t *key, int argc, char **argv);
int bpf_trace_pipe(void);
void bpf_print_ops(struct rtattr *bpf_ops, __u16 len);
int bpf_prog_load(enum bpf_prog_type type, const struct bpf_insn *insns,
size_t size_insns, const char *license, char *log,
size_t size_log);
int bpf_prog_attach_fd(int prog_fd, int target_fd, enum bpf_attach_type type);
int bpf_prog_detach_fd(int target_fd, enum bpf_attach_type type);
int bpf_dump_prog_info(FILE *f, uint32_t id);
#ifdef HAVE_ELF
int bpf_send_map_fds(const char *path, const char *obj);
int bpf_recv_map_fds(const char *path, int *fds, struct bpf_map_aux *aux,
unsigned int entries);
#else
static inline int bpf_send_map_fds(const char *path, const char *obj)
{
return 0;
}
static inline int bpf_recv_map_fds(const char *path, int *fds,
struct bpf_map_aux *aux,
unsigned int entries)
{
return -1;
}
#endif /* HAVE_ELF */
const char *get_libbpf_version(void);
#endif /* __BPF_UTIL__ */