linux_dsm_epyc7002/tools/lib/bpf/bpf.c
Daniel Borkmann d859900c4c bpf, libbpf: support global data/bss/rodata sections
This work adds BPF loader support for global data sections
to libbpf. This allows to write BPF programs in more natural
C-like way by being able to define global variables and const
data.

Back at LPC 2018 [0] we presented a first prototype which
implemented support for global data sections by extending BPF
syscall where union bpf_attr would get additional memory/size
pair for each section passed during prog load in order to later
add this base address into the ldimm64 instruction along with
the user provided offset when accessing a variable. Consensus
from LPC was that for proper upstream support, it would be
more desirable to use maps instead of bpf_attr extension as
this would allow for introspection of these sections as well
as potential live updates of their content. This work follows
this path by taking the following steps from loader side:

 1) In bpf_object__elf_collect() step we pick up ".data",
    ".rodata", and ".bss" section information.

 2) If present, in bpf_object__init_internal_map() we add
    maps to the obj's map array that corresponds to each
    of the present sections. Given section size and access
    properties can differ, a single entry array map is
    created with value size that is corresponding to the
    ELF section size of .data, .bss or .rodata. These
    internal maps are integrated into the normal map
    handling of libbpf such that when user traverses all
    obj maps, they can be differentiated from user-created
    ones via bpf_map__is_internal(). In later steps when
    we actually create these maps in the kernel via
    bpf_object__create_maps(), then for .data and .rodata
    sections their content is copied into the map through
    bpf_map_update_elem(). For .bss this is not necessary
    since array map is already zero-initialized by default.
    Additionally, for .rodata the map is frozen as read-only
    after setup, such that neither from program nor syscall
    side writes would be possible.

 3) In bpf_program__collect_reloc() step, we record the
    corresponding map, insn index, and relocation type for
    the global data.

 4) And last but not least in the actual relocation step in
    bpf_program__relocate(), we mark the ldimm64 instruction
    with src_reg = BPF_PSEUDO_MAP_VALUE where in the first
    imm field the map's file descriptor is stored as similarly
    done as in BPF_PSEUDO_MAP_FD, and in the second imm field
    (as ldimm64 is 2-insn wide) we store the access offset
    into the section. Given these maps have only single element
    ldimm64's off remains zero in both parts.

 5) On kernel side, this special marked BPF_PSEUDO_MAP_VALUE
    load will then store the actual target address in order
    to have a 'map-lookup'-free access. That is, the actual
    map value base address + offset. The destination register
    in the verifier will then be marked as PTR_TO_MAP_VALUE,
    containing the fixed offset as reg->off and backing BPF
    map as reg->map_ptr. Meaning, it's treated as any other
    normal map value from verification side, only with
    efficient, direct value access instead of actual call to
    map lookup helper as in the typical case.

Currently, only support for static global variables has been
added, and libbpf rejects non-static global variables from
loading. This can be lifted until we have proper semantics
for how BPF will treat multi-object BPF loads. From BTF side,
libbpf will set the value type id of the types corresponding
to the ".bss", ".data" and ".rodata" names which LLVM will
emit without the object name prefix. The key type will be
left as zero, thus making use of the key-less BTF option in
array maps.

Simple example dump of program using globals vars in each
section:

  # bpftool prog
  [...]
  6784: sched_cls  name load_static_dat  tag a7e1291567277844  gpl
        loaded_at 2019-03-11T15:39:34+0000  uid 0
        xlated 1776B  jited 993B  memlock 4096B  map_ids 2238,2237,2235,2236,2239,2240

  # bpftool map show id 2237
  2237: array  name test_glo.bss  flags 0x0
        key 4B  value 64B  max_entries 1  memlock 4096B
  # bpftool map show id 2235
  2235: array  name test_glo.data  flags 0x0
        key 4B  value 64B  max_entries 1  memlock 4096B
  # bpftool map show id 2236
  2236: array  name test_glo.rodata  flags 0x80
        key 4B  value 96B  max_entries 1  memlock 4096B

  # bpftool prog dump xlated id 6784
  int load_static_data(struct __sk_buff * skb):
  ; int load_static_data(struct __sk_buff *skb)
     0: (b7) r6 = 0
  ; test_reloc(number, 0, &num0);
     1: (63) *(u32 *)(r10 -4) = r6
     2: (bf) r2 = r10
  ; int load_static_data(struct __sk_buff *skb)
     3: (07) r2 += -4
  ; test_reloc(number, 0, &num0);
     4: (18) r1 = map[id:2238]
     6: (18) r3 = map[id:2237][0]+0    <-- direct addr in .bss area
     8: (b7) r4 = 0
     9: (85) call array_map_update_elem#100464
    10: (b7) r1 = 1
  ; test_reloc(number, 1, &num1);
  [...]
  ; test_reloc(string, 2, str2);
   120: (18) r8 = map[id:2237][0]+16   <-- same here at offset +16
   122: (18) r1 = map[id:2239]
   124: (18) r3 = map[id:2237][0]+16
   126: (b7) r4 = 0
   127: (85) call array_map_update_elem#100464
   128: (b7) r1 = 120
  ; str1[5] = 'x';
   129: (73) *(u8 *)(r9 +5) = r1
  ; test_reloc(string, 3, str1);
   130: (b7) r1 = 3
   131: (63) *(u32 *)(r10 -4) = r1
   132: (b7) r9 = 3
   133: (bf) r2 = r10
  ; int load_static_data(struct __sk_buff *skb)
   134: (07) r2 += -4
  ; test_reloc(string, 3, str1);
   135: (18) r1 = map[id:2239]
   137: (18) r3 = map[id:2235][0]+16   <-- direct addr in .data area
   139: (b7) r4 = 0
   140: (85) call array_map_update_elem#100464
   141: (b7) r1 = 111
  ; __builtin_memcpy(&str2[2], "hello", sizeof("hello"));
   142: (73) *(u8 *)(r8 +6) = r1       <-- further access based on .bss data
   143: (b7) r1 = 108
   144: (73) *(u8 *)(r8 +5) = r1
  [...]

For Cilium use-case in particular, this enables migrating configuration
constants from Cilium daemon's generated header defines into global
data sections such that expensive runtime recompilations with LLVM can
be avoided altogether. Instead, the ELF file becomes effectively a
"template", meaning, it is compiled only once (!) and the Cilium daemon
will then rewrite relevant configuration data from the ELF's .data or
.rodata sections directly instead of recompiling the program. The
updated ELF is then loaded into the kernel and atomically replaces
the existing program in the networking datapath. More info in [0].

Based upon recent fix in LLVM, commit c0db6b6bd444 ("[BPF] Don't fail
for static variables").

  [0] LPC 2018, BPF track, "ELF relocation for static data in BPF",
      http://vger.kernel.org/lpc-bpf2018.html#session-3

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-04-09 17:05:47 -07:00

702 lines
17 KiB
C

// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
/*
* common eBPF ELF operations.
*
* Copyright (C) 2013-2015 Alexei Starovoitov <ast@kernel.org>
* Copyright (C) 2015 Wang Nan <wangnan0@huawei.com>
* Copyright (C) 2015 Huawei Inc.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation;
* version 2.1 of the License (not later!)
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this program; if not, see <http://www.gnu.org/licenses>
*/
#include <stdlib.h>
#include <string.h>
#include <memory.h>
#include <unistd.h>
#include <asm/unistd.h>
#include <linux/bpf.h>
#include "bpf.h"
#include "libbpf.h"
#include <errno.h>
/*
* When building perf, unistd.h is overridden. __NR_bpf is
* required to be defined explicitly.
*/
#ifndef __NR_bpf
# if defined(__i386__)
# define __NR_bpf 357
# elif defined(__x86_64__)
# define __NR_bpf 321
# elif defined(__aarch64__)
# define __NR_bpf 280
# elif defined(__sparc__)
# define __NR_bpf 349
# elif defined(__s390__)
# define __NR_bpf 351
# else
# error __NR_bpf not defined. libbpf does not support your arch.
# endif
#endif
#ifndef min
#define min(x, y) ((x) < (y) ? (x) : (y))
#endif
static inline __u64 ptr_to_u64(const void *ptr)
{
return (__u64) (unsigned long) ptr;
}
static inline int sys_bpf(enum bpf_cmd cmd, union bpf_attr *attr,
unsigned int size)
{
return syscall(__NR_bpf, cmd, attr, size);
}
static inline int sys_bpf_prog_load(union bpf_attr *attr, unsigned int size)
{
int fd;
do {
fd = sys_bpf(BPF_PROG_LOAD, attr, size);
} while (fd < 0 && errno == EAGAIN);
return fd;
}
int bpf_create_map_xattr(const struct bpf_create_map_attr *create_attr)
{
__u32 name_len = create_attr->name ? strlen(create_attr->name) : 0;
union bpf_attr attr;
memset(&attr, '\0', sizeof(attr));
attr.map_type = create_attr->map_type;
attr.key_size = create_attr->key_size;
attr.value_size = create_attr->value_size;
attr.max_entries = create_attr->max_entries;
attr.map_flags = create_attr->map_flags;
memcpy(attr.map_name, create_attr->name,
min(name_len, BPF_OBJ_NAME_LEN - 1));
attr.numa_node = create_attr->numa_node;
attr.btf_fd = create_attr->btf_fd;
attr.btf_key_type_id = create_attr->btf_key_type_id;
attr.btf_value_type_id = create_attr->btf_value_type_id;
attr.map_ifindex = create_attr->map_ifindex;
attr.inner_map_fd = create_attr->inner_map_fd;
return sys_bpf(BPF_MAP_CREATE, &attr, sizeof(attr));
}
int bpf_create_map_node(enum bpf_map_type map_type, const char *name,
int key_size, int value_size, int max_entries,
__u32 map_flags, int node)
{
struct bpf_create_map_attr map_attr = {};
map_attr.name = name;
map_attr.map_type = map_type;
map_attr.map_flags = map_flags;
map_attr.key_size = key_size;
map_attr.value_size = value_size;
map_attr.max_entries = max_entries;
if (node >= 0) {
map_attr.numa_node = node;
map_attr.map_flags |= BPF_F_NUMA_NODE;
}
return bpf_create_map_xattr(&map_attr);
}
int bpf_create_map(enum bpf_map_type map_type, int key_size,
int value_size, int max_entries, __u32 map_flags)
{
struct bpf_create_map_attr map_attr = {};
map_attr.map_type = map_type;
map_attr.map_flags = map_flags;
map_attr.key_size = key_size;
map_attr.value_size = value_size;
map_attr.max_entries = max_entries;
return bpf_create_map_xattr(&map_attr);
}
int bpf_create_map_name(enum bpf_map_type map_type, const char *name,
int key_size, int value_size, int max_entries,
__u32 map_flags)
{
struct bpf_create_map_attr map_attr = {};
map_attr.name = name;
map_attr.map_type = map_type;
map_attr.map_flags = map_flags;
map_attr.key_size = key_size;
map_attr.value_size = value_size;
map_attr.max_entries = max_entries;
return bpf_create_map_xattr(&map_attr);
}
int bpf_create_map_in_map_node(enum bpf_map_type map_type, const char *name,
int key_size, int inner_map_fd, int max_entries,
__u32 map_flags, int node)
{
__u32 name_len = name ? strlen(name) : 0;
union bpf_attr attr;
memset(&attr, '\0', sizeof(attr));
attr.map_type = map_type;
attr.key_size = key_size;
attr.value_size = 4;
attr.inner_map_fd = inner_map_fd;
attr.max_entries = max_entries;
attr.map_flags = map_flags;
memcpy(attr.map_name, name, min(name_len, BPF_OBJ_NAME_LEN - 1));
if (node >= 0) {
attr.map_flags |= BPF_F_NUMA_NODE;
attr.numa_node = node;
}
return sys_bpf(BPF_MAP_CREATE, &attr, sizeof(attr));
}
int bpf_create_map_in_map(enum bpf_map_type map_type, const char *name,
int key_size, int inner_map_fd, int max_entries,
__u32 map_flags)
{
return bpf_create_map_in_map_node(map_type, name, key_size,
inner_map_fd, max_entries, map_flags,
-1);
}
static void *
alloc_zero_tailing_info(const void *orecord, __u32 cnt,
__u32 actual_rec_size, __u32 expected_rec_size)
{
__u64 info_len = actual_rec_size * cnt;
void *info, *nrecord;
int i;
info = malloc(info_len);
if (!info)
return NULL;
/* zero out bytes kernel does not understand */
nrecord = info;
for (i = 0; i < cnt; i++) {
memcpy(nrecord, orecord, expected_rec_size);
memset(nrecord + expected_rec_size, 0,
actual_rec_size - expected_rec_size);
orecord += actual_rec_size;
nrecord += actual_rec_size;
}
return info;
}
int bpf_load_program_xattr(const struct bpf_load_program_attr *load_attr,
char *log_buf, size_t log_buf_sz)
{
void *finfo = NULL, *linfo = NULL;
union bpf_attr attr;
__u32 log_level;
__u32 name_len;
int fd;
if (!load_attr || !log_buf != !log_buf_sz)
return -EINVAL;
log_level = load_attr->log_level;
if (log_level > (4 | 2 | 1) || (log_level && !log_buf))
return -EINVAL;
name_len = load_attr->name ? strlen(load_attr->name) : 0;
memset(&attr, 0, sizeof(attr));
attr.prog_type = load_attr->prog_type;
attr.expected_attach_type = load_attr->expected_attach_type;
attr.insn_cnt = (__u32)load_attr->insns_cnt;
attr.insns = ptr_to_u64(load_attr->insns);
attr.license = ptr_to_u64(load_attr->license);
attr.log_level = log_level;
if (log_level) {
attr.log_buf = ptr_to_u64(log_buf);
attr.log_size = log_buf_sz;
} else {
attr.log_buf = ptr_to_u64(NULL);
attr.log_size = 0;
}
attr.kern_version = load_attr->kern_version;
attr.prog_ifindex = load_attr->prog_ifindex;
attr.prog_btf_fd = load_attr->prog_btf_fd;
attr.func_info_rec_size = load_attr->func_info_rec_size;
attr.func_info_cnt = load_attr->func_info_cnt;
attr.func_info = ptr_to_u64(load_attr->func_info);
attr.line_info_rec_size = load_attr->line_info_rec_size;
attr.line_info_cnt = load_attr->line_info_cnt;
attr.line_info = ptr_to_u64(load_attr->line_info);
memcpy(attr.prog_name, load_attr->name,
min(name_len, BPF_OBJ_NAME_LEN - 1));
fd = sys_bpf_prog_load(&attr, sizeof(attr));
if (fd >= 0)
return fd;
/* After bpf_prog_load, the kernel may modify certain attributes
* to give user space a hint how to deal with loading failure.
* Check to see whether we can make some changes and load again.
*/
while (errno == E2BIG && (!finfo || !linfo)) {
if (!finfo && attr.func_info_cnt &&
attr.func_info_rec_size < load_attr->func_info_rec_size) {
/* try with corrected func info records */
finfo = alloc_zero_tailing_info(load_attr->func_info,
load_attr->func_info_cnt,
load_attr->func_info_rec_size,
attr.func_info_rec_size);
if (!finfo)
goto done;
attr.func_info = ptr_to_u64(finfo);
attr.func_info_rec_size = load_attr->func_info_rec_size;
} else if (!linfo && attr.line_info_cnt &&
attr.line_info_rec_size <
load_attr->line_info_rec_size) {
linfo = alloc_zero_tailing_info(load_attr->line_info,
load_attr->line_info_cnt,
load_attr->line_info_rec_size,
attr.line_info_rec_size);
if (!linfo)
goto done;
attr.line_info = ptr_to_u64(linfo);
attr.line_info_rec_size = load_attr->line_info_rec_size;
} else {
break;
}
fd = sys_bpf_prog_load(&attr, sizeof(attr));
if (fd >= 0)
goto done;
}
if (log_level || !log_buf)
goto done;
/* Try again with log */
attr.log_buf = ptr_to_u64(log_buf);
attr.log_size = log_buf_sz;
attr.log_level = 1;
log_buf[0] = 0;
fd = sys_bpf_prog_load(&attr, sizeof(attr));
done:
free(finfo);
free(linfo);
return fd;
}
int bpf_load_program(enum bpf_prog_type type, const struct bpf_insn *insns,
size_t insns_cnt, const char *license,
__u32 kern_version, char *log_buf,
size_t log_buf_sz)
{
struct bpf_load_program_attr load_attr;
memset(&load_attr, 0, sizeof(struct bpf_load_program_attr));
load_attr.prog_type = type;
load_attr.expected_attach_type = 0;
load_attr.name = NULL;
load_attr.insns = insns;
load_attr.insns_cnt = insns_cnt;
load_attr.license = license;
load_attr.kern_version = kern_version;
return bpf_load_program_xattr(&load_attr, log_buf, log_buf_sz);
}
int bpf_verify_program(enum bpf_prog_type type, const struct bpf_insn *insns,
size_t insns_cnt, __u32 prog_flags, const char *license,
__u32 kern_version, char *log_buf, size_t log_buf_sz,
int log_level)
{
union bpf_attr attr;
memset(&attr, 0, sizeof(attr));
attr.prog_type = type;
attr.insn_cnt = (__u32)insns_cnt;
attr.insns = ptr_to_u64(insns);
attr.license = ptr_to_u64(license);
attr.log_buf = ptr_to_u64(log_buf);
attr.log_size = log_buf_sz;
attr.log_level = log_level;
log_buf[0] = 0;
attr.kern_version = kern_version;
attr.prog_flags = prog_flags;
return sys_bpf_prog_load(&attr, sizeof(attr));
}
int bpf_map_update_elem(int fd, const void *key, const void *value,
__u64 flags)
{
union bpf_attr attr;
memset(&attr, 0, sizeof(attr));
attr.map_fd = fd;
attr.key = ptr_to_u64(key);
attr.value = ptr_to_u64(value);
attr.flags = flags;
return sys_bpf(BPF_MAP_UPDATE_ELEM, &attr, sizeof(attr));
}
int bpf_map_lookup_elem(int fd, const void *key, void *value)
{
union bpf_attr attr;
memset(&attr, 0, sizeof(attr));
attr.map_fd = fd;
attr.key = ptr_to_u64(key);
attr.value = ptr_to_u64(value);
return sys_bpf(BPF_MAP_LOOKUP_ELEM, &attr, sizeof(attr));
}
int bpf_map_lookup_elem_flags(int fd, const void *key, void *value, __u64 flags)
{
union bpf_attr attr;
memset(&attr, 0, sizeof(attr));
attr.map_fd = fd;
attr.key = ptr_to_u64(key);
attr.value = ptr_to_u64(value);
attr.flags = flags;
return sys_bpf(BPF_MAP_LOOKUP_ELEM, &attr, sizeof(attr));
}
int bpf_map_lookup_and_delete_elem(int fd, const void *key, void *value)
{
union bpf_attr attr;
memset(&attr, 0, sizeof(attr));
attr.map_fd = fd;
attr.key = ptr_to_u64(key);
attr.value = ptr_to_u64(value);
return sys_bpf(BPF_MAP_LOOKUP_AND_DELETE_ELEM, &attr, sizeof(attr));
}
int bpf_map_delete_elem(int fd, const void *key)
{
union bpf_attr attr;
memset(&attr, 0, sizeof(attr));
attr.map_fd = fd;
attr.key = ptr_to_u64(key);
return sys_bpf(BPF_MAP_DELETE_ELEM, &attr, sizeof(attr));
}
int bpf_map_get_next_key(int fd, const void *key, void *next_key)
{
union bpf_attr attr;
memset(&attr, 0, sizeof(attr));
attr.map_fd = fd;
attr.key = ptr_to_u64(key);
attr.next_key = ptr_to_u64(next_key);
return sys_bpf(BPF_MAP_GET_NEXT_KEY, &attr, sizeof(attr));
}
int bpf_map_freeze(int fd)
{
union bpf_attr attr;
memset(&attr, 0, sizeof(attr));
attr.map_fd = fd;
return sys_bpf(BPF_MAP_FREEZE, &attr, sizeof(attr));
}
int bpf_obj_pin(int fd, const char *pathname)
{
union bpf_attr attr;
memset(&attr, 0, sizeof(attr));
attr.pathname = ptr_to_u64((void *)pathname);
attr.bpf_fd = fd;
return sys_bpf(BPF_OBJ_PIN, &attr, sizeof(attr));
}
int bpf_obj_get(const char *pathname)
{
union bpf_attr attr;
memset(&attr, 0, sizeof(attr));
attr.pathname = ptr_to_u64((void *)pathname);
return sys_bpf(BPF_OBJ_GET, &attr, sizeof(attr));
}
int bpf_prog_attach(int prog_fd, int target_fd, enum bpf_attach_type type,
unsigned int flags)
{
union bpf_attr attr;
memset(&attr, 0, sizeof(attr));
attr.target_fd = target_fd;
attr.attach_bpf_fd = prog_fd;
attr.attach_type = type;
attr.attach_flags = flags;
return sys_bpf(BPF_PROG_ATTACH, &attr, sizeof(attr));
}
int bpf_prog_detach(int target_fd, enum bpf_attach_type type)
{
union bpf_attr attr;
memset(&attr, 0, sizeof(attr));
attr.target_fd = target_fd;
attr.attach_type = type;
return sys_bpf(BPF_PROG_DETACH, &attr, sizeof(attr));
}
int bpf_prog_detach2(int prog_fd, int target_fd, enum bpf_attach_type type)
{
union bpf_attr attr;
memset(&attr, 0, sizeof(attr));
attr.target_fd = target_fd;
attr.attach_bpf_fd = prog_fd;
attr.attach_type = type;
return sys_bpf(BPF_PROG_DETACH, &attr, sizeof(attr));
}
int bpf_prog_query(int target_fd, enum bpf_attach_type type, __u32 query_flags,
__u32 *attach_flags, __u32 *prog_ids, __u32 *prog_cnt)
{
union bpf_attr attr;
int ret;
memset(&attr, 0, sizeof(attr));
attr.query.target_fd = target_fd;
attr.query.attach_type = type;
attr.query.query_flags = query_flags;
attr.query.prog_cnt = *prog_cnt;
attr.query.prog_ids = ptr_to_u64(prog_ids);
ret = sys_bpf(BPF_PROG_QUERY, &attr, sizeof(attr));
if (attach_flags)
*attach_flags = attr.query.attach_flags;
*prog_cnt = attr.query.prog_cnt;
return ret;
}
int bpf_prog_test_run(int prog_fd, int repeat, void *data, __u32 size,
void *data_out, __u32 *size_out, __u32 *retval,
__u32 *duration)
{
union bpf_attr attr;
int ret;
memset(&attr, 0, sizeof(attr));
attr.test.prog_fd = prog_fd;
attr.test.data_in = ptr_to_u64(data);
attr.test.data_out = ptr_to_u64(data_out);
attr.test.data_size_in = size;
attr.test.repeat = repeat;
ret = sys_bpf(BPF_PROG_TEST_RUN, &attr, sizeof(attr));
if (size_out)
*size_out = attr.test.data_size_out;
if (retval)
*retval = attr.test.retval;
if (duration)
*duration = attr.test.duration;
return ret;
}
int bpf_prog_test_run_xattr(struct bpf_prog_test_run_attr *test_attr)
{
union bpf_attr attr;
int ret;
if (!test_attr->data_out && test_attr->data_size_out > 0)
return -EINVAL;
memset(&attr, 0, sizeof(attr));
attr.test.prog_fd = test_attr->prog_fd;
attr.test.data_in = ptr_to_u64(test_attr->data_in);
attr.test.data_out = ptr_to_u64(test_attr->data_out);
attr.test.data_size_in = test_attr->data_size_in;
attr.test.data_size_out = test_attr->data_size_out;
attr.test.repeat = test_attr->repeat;
ret = sys_bpf(BPF_PROG_TEST_RUN, &attr, sizeof(attr));
test_attr->data_size_out = attr.test.data_size_out;
test_attr->retval = attr.test.retval;
test_attr->duration = attr.test.duration;
return ret;
}
int bpf_prog_get_next_id(__u32 start_id, __u32 *next_id)
{
union bpf_attr attr;
int err;
memset(&attr, 0, sizeof(attr));
attr.start_id = start_id;
err = sys_bpf(BPF_PROG_GET_NEXT_ID, &attr, sizeof(attr));
if (!err)
*next_id = attr.next_id;
return err;
}
int bpf_map_get_next_id(__u32 start_id, __u32 *next_id)
{
union bpf_attr attr;
int err;
memset(&attr, 0, sizeof(attr));
attr.start_id = start_id;
err = sys_bpf(BPF_MAP_GET_NEXT_ID, &attr, sizeof(attr));
if (!err)
*next_id = attr.next_id;
return err;
}
int bpf_prog_get_fd_by_id(__u32 id)
{
union bpf_attr attr;
memset(&attr, 0, sizeof(attr));
attr.prog_id = id;
return sys_bpf(BPF_PROG_GET_FD_BY_ID, &attr, sizeof(attr));
}
int bpf_map_get_fd_by_id(__u32 id)
{
union bpf_attr attr;
memset(&attr, 0, sizeof(attr));
attr.map_id = id;
return sys_bpf(BPF_MAP_GET_FD_BY_ID, &attr, sizeof(attr));
}
int bpf_btf_get_fd_by_id(__u32 id)
{
union bpf_attr attr;
memset(&attr, 0, sizeof(attr));
attr.btf_id = id;
return sys_bpf(BPF_BTF_GET_FD_BY_ID, &attr, sizeof(attr));
}
int bpf_obj_get_info_by_fd(int prog_fd, void *info, __u32 *info_len)
{
union bpf_attr attr;
int err;
memset(&attr, 0, sizeof(attr));
attr.info.bpf_fd = prog_fd;
attr.info.info_len = *info_len;
attr.info.info = ptr_to_u64(info);
err = sys_bpf(BPF_OBJ_GET_INFO_BY_FD, &attr, sizeof(attr));
if (!err)
*info_len = attr.info.info_len;
return err;
}
int bpf_raw_tracepoint_open(const char *name, int prog_fd)
{
union bpf_attr attr;
memset(&attr, 0, sizeof(attr));
attr.raw_tracepoint.name = ptr_to_u64(name);
attr.raw_tracepoint.prog_fd = prog_fd;
return sys_bpf(BPF_RAW_TRACEPOINT_OPEN, &attr, sizeof(attr));
}
int bpf_load_btf(void *btf, __u32 btf_size, char *log_buf, __u32 log_buf_size,
bool do_log)
{
union bpf_attr attr = {};
int fd;
attr.btf = ptr_to_u64(btf);
attr.btf_size = btf_size;
retry:
if (do_log && log_buf && log_buf_size) {
attr.btf_log_level = 1;
attr.btf_log_size = log_buf_size;
attr.btf_log_buf = ptr_to_u64(log_buf);
}
fd = sys_bpf(BPF_BTF_LOAD, &attr, sizeof(attr));
if (fd == -1 && !do_log && log_buf && log_buf_size) {
do_log = true;
goto retry;
}
return fd;
}
int bpf_task_fd_query(int pid, int fd, __u32 flags, char *buf, __u32 *buf_len,
__u32 *prog_id, __u32 *fd_type, __u64 *probe_offset,
__u64 *probe_addr)
{
union bpf_attr attr = {};
int err;
attr.task_fd_query.pid = pid;
attr.task_fd_query.fd = fd;
attr.task_fd_query.flags = flags;
attr.task_fd_query.buf = ptr_to_u64(buf);
attr.task_fd_query.buf_len = *buf_len;
err = sys_bpf(BPF_TASK_FD_QUERY, &attr, sizeof(attr));
*buf_len = attr.task_fd_query.buf_len;
*prog_id = attr.task_fd_query.prog_id;
*fd_type = attr.task_fd_query.fd_type;
*probe_offset = attr.task_fd_query.probe_offset;
*probe_addr = attr.task_fd_query.probe_addr;
return err;
}