tools/lib/bpf/bpf.c

   1 /*
   2  * common eBPF ELF operations.
   3  *
   4  * Copyright (C) 2013-2015 Alexei Starovoitov <ast@kernel.org>
   5  * Copyright (C) 2015 Wang Nan <wangnan0@huawei.com>
   6  * Copyright (C) 2015 Huawei Inc.
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation;
  11  * version 2.1 of the License (not later!)
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this program; if not,  see <http://www.gnu.org/licenses>
  20  */
  21
  22 #include <stdlib.h>
  23 #include <memory.h>
  24 #include <unistd.h>
  25 #include <asm/unistd.h>
  26 #include <linux/bpf.h>
  27 #include "bpf.h"
  28
  29 /*
  30  * When building perf, unistd.h is overridden. __NR_bpf is
  31  * required to be defined explicitly.
  32  */
  33 #ifndef __NR_bpf
  34 # if defined(__i386__)
  35 #  define __NR_bpf 357
  36 # elif defined(__x86_64__)
  37 #  define __NR_bpf 321
  38 # elif defined(__aarch64__)
  39 #  define __NR_bpf 280
  40 # elif defined(__sparc__)
  41 #  define __NR_bpf 349
  42 # elif defined(__s390__)
  43 #  define __NR_bpf 351
  44 # else
  45 #  error __NR_bpf not defined. libbpf does not support your arch.
  46 # endif
  47 #endif
  48
  49 static inline __u64 ptr_to_u64(const void *ptr)
  50 {
  51         return (__u64) (unsigned long) ptr;
  52 }
  53
  54 static inline int sys_bpf(enum bpf_cmd cmd, union bpf_attr *attr,
  55                           unsigned int size)
  56 {
  57         return syscall(__NR_bpf, cmd, attr, size);
  58 }
  59
  60 int bpf_create_map(enum bpf_map_type map_type, int key_size,
  61                    int value_size, int max_entries, __u32 map_flags)
  62 {
  63         union bpf_attr attr;
  64
  65         memset(&attr, '\0', sizeof(attr));
  66
  67         attr.map_type = map_type;
  68         attr.key_size = key_size;
  69         attr.value_size = value_size;
  70         attr.max_entries = max_entries;
  71         attr.map_flags = map_flags;
  72
  73         return sys_bpf(BPF_MAP_CREATE, &attr, sizeof(attr));
  74 }
  75
  76 int bpf_create_map_in_map(enum bpf_map_type map_type, int key_size,
  77                           int inner_map_fd, int max_entries, __u32 map_flags)
  78 {
  79         union bpf_attr attr;
  80
  81         memset(&attr, '\0', sizeof(attr));
  82
  83         attr.map_type = map_type;
  84         attr.key_size = key_size;
  85         attr.value_size = 4;
  86         attr.inner_map_fd = inner_map_fd;
  87         attr.max_entries = max_entries;
  88         attr.map_flags = map_flags;
  89
  90         return sys_bpf(BPF_MAP_CREATE, &attr, sizeof(attr));
  91 }
  92
  93 int bpf_load_program(enum bpf_prog_type type, const struct bpf_insn *insns,
  94                      size_t insns_cnt, const char *license,
  95                      __u32 kern_version, char *log_buf, size_t log_buf_sz)
  96 {
  97         int fd;
  98         union bpf_attr attr;
  99
 100         bzero(&attr, sizeof(attr));
 101         attr.prog_type = type;
 102         attr.insn_cnt = (__u32)insns_cnt;
 103         attr.insns = ptr_to_u64(insns);
 104         attr.license = ptr_to_u64(license);
 105         attr.log_buf = ptr_to_u64(NULL);
 106         attr.log_size = 0;
 107         attr.log_level = 0;
 108         attr.kern_version = kern_version;
 109
 110         fd = sys_bpf(BPF_PROG_LOAD, &attr, sizeof(attr));
 111         if (fd >= 0 || !log_buf || !log_buf_sz)
 112                 return fd;
 113
 114         /* Try again with log */
 115         attr.log_buf = ptr_to_u64(log_buf);
 116         attr.log_size = log_buf_sz;
 117         attr.log_level = 1;
 118         log_buf[0] = 0;
 119         return sys_bpf(BPF_PROG_LOAD, &attr, sizeof(attr));
 120 }
 121
 122 int bpf_verify_program(enum bpf_prog_type type, const struct bpf_insn *insns,
 123                        size_t insns_cnt, int strict_alignment,
 124                        const char *license, __u32 kern_version,
 125                        char *log_buf, size_t log_buf_sz, int log_level)
 126 {
 127         union bpf_attr attr;
 128
 129         bzero(&attr, sizeof(attr));
 130         attr.prog_type = type;
 131         attr.insn_cnt = (__u32)insns_cnt;
 132         attr.insns = ptr_to_u64(insns);
 133         attr.license = ptr_to_u64(license);
 134         attr.log_buf = ptr_to_u64(log_buf);
 135         attr.log_size = log_buf_sz;
 136         attr.log_level = log_level;
 137         log_buf[0] = 0;
 138         attr.kern_version = kern_version;
 139         attr.prog_flags = strict_alignment ? BPF_F_STRICT_ALIGNMENT : 0;
 140
 141         return sys_bpf(BPF_PROG_LOAD, &attr, sizeof(attr));
 142 }
 143
 144 int bpf_map_update_elem(int fd, const void *key, const void *value,
 145                         __u64 flags)
 146 {
 147         union bpf_attr attr;
 148
 149         bzero(&attr, sizeof(attr));
 150         attr.map_fd = fd;
 151         attr.key = ptr_to_u64(key);
 152         attr.value = ptr_to_u64(value);
 153         attr.flags = flags;
 154
 155         return sys_bpf(BPF_MAP_UPDATE_ELEM, &attr, sizeof(attr));
 156 }
 157
 158 int bpf_map_lookup_elem(int fd, const void *key, void *value)
 159 {
 160         union bpf_attr attr;
 161
 162         bzero(&attr, sizeof(attr));
 163         attr.map_fd = fd;
 164         attr.key = ptr_to_u64(key);
 165         attr.value = ptr_to_u64(value);
 166
 167         return sys_bpf(BPF_MAP_LOOKUP_ELEM, &attr, sizeof(attr));
 168 }
 169
 170 int bpf_map_delete_elem(int fd, const void *key)
 171 {
 172         union bpf_attr attr;
 173
 174         bzero(&attr, sizeof(attr));
 175         attr.map_fd = fd;
 176         attr.key = ptr_to_u64(key);
 177
 178         return sys_bpf(BPF_MAP_DELETE_ELEM, &attr, sizeof(attr));
 179 }
 180
 181 int bpf_map_get_next_key(int fd, const void *key, void *next_key)
 182 {
 183         union bpf_attr attr;
 184
 185         bzero(&attr, sizeof(attr));
 186         attr.map_fd = fd;
 187         attr.key = ptr_to_u64(key);
 188         attr.next_key = ptr_to_u64(next_key);
 189
 190         return sys_bpf(BPF_MAP_GET_NEXT_KEY, &attr, sizeof(attr));
 191 }
 192
 193 int bpf_obj_pin(int fd, const char *pathname)
 194 {
 195         union bpf_attr attr;
 196
 197         bzero(&attr, sizeof(attr));
 198         attr.pathname = ptr_to_u64((void *)pathname);
 199         attr.bpf_fd = fd;
 200
 201         return sys_bpf(BPF_OBJ_PIN, &attr, sizeof(attr));
 202 }
 203
 204 int bpf_obj_get(const char *pathname)
 205 {
 206         union bpf_attr attr;
 207
 208         bzero(&attr, sizeof(attr));
 209         attr.pathname = ptr_to_u64((void *)pathname);
 210
 211         return sys_bpf(BPF_OBJ_GET, &attr, sizeof(attr));
 212 }
 213
 214 int bpf_prog_attach(int prog_fd, int target_fd, enum bpf_attach_type type,
 215                     unsigned int flags)
 216 {
 217         union bpf_attr attr;
 218
 219         bzero(&attr, sizeof(attr));
 220         attr.target_fd     = target_fd;
 221         attr.attach_bpf_fd = prog_fd;
 222         attr.attach_type   = type;
 223         attr.attach_flags  = flags;
 224
 225         return sys_bpf(BPF_PROG_ATTACH, &attr, sizeof(attr));
 226 }
 227
 228 int bpf_prog_detach(int target_fd, enum bpf_attach_type type)
 229 {
 230         union bpf_attr attr;
 231
 232         bzero(&attr, sizeof(attr));
 233         attr.target_fd   = target_fd;
 234         attr.attach_type = type;
 235
 236         return sys_bpf(BPF_PROG_DETACH, &attr, sizeof(attr));
 237 }
 238
 239 int bpf_prog_test_run(int prog_fd, int repeat, void *data, __u32 size,
 240                       void *data_out, __u32 *size_out, __u32 *retval,
 241                       __u32 *duration)
 242 {
 243         union bpf_attr attr;
 244         int ret;
 245
 246         bzero(&attr, sizeof(attr));
 247         attr.test.prog_fd = prog_fd;
 248         attr.test.data_in = ptr_to_u64(data);
 249         attr.test.data_out = ptr_to_u64(data_out);
 250         attr.test.data_size_in = size;
 251         attr.test.repeat = repeat;
 252
 253         ret = sys_bpf(BPF_PROG_TEST_RUN, &attr, sizeof(attr));
 254         if (size_out)
 255                 *size_out = attr.test.data_size_out;
 256         if (retval)
 257                 *retval = attr.test.retval;
 258         if (duration)
 259                 *duration = attr.test.duration;
 260         return ret;
 261 }
 262
 263 int bpf_prog_get_next_id(__u32 start_id, __u32 *next_id)
 264 {
 265         union bpf_attr attr;
 266         int err;
 267
 268         bzero(&attr, sizeof(attr));
 269         attr.start_id = start_id;
 270
 271         err = sys_bpf(BPF_PROG_GET_NEXT_ID, &attr, sizeof(attr));
 272         if (!err)
 273                 *next_id = attr.next_id;
 274
 275         return err;
 276 }
 277
 278 int bpf_map_get_next_id(__u32 start_id, __u32 *next_id)
 279 {
 280         union bpf_attr attr;
 281         int err;
 282
 283         bzero(&attr, sizeof(attr));
 284         attr.start_id = start_id;
 285
 286         err = sys_bpf(BPF_MAP_GET_NEXT_ID, &attr, sizeof(attr));
 287         if (!err)
 288                 *next_id = attr.next_id;
 289
 290         return err;
 291 }
 292
 293 int bpf_prog_get_fd_by_id(__u32 id)
 294 {
 295         union bpf_attr attr;
 296
 297         bzero(&attr, sizeof(attr));
 298         attr.prog_id = id;
 299
 300         return sys_bpf(BPF_PROG_GET_FD_BY_ID, &attr, sizeof(attr));
 301 }
 302
 303 int bpf_map_get_fd_by_id(__u32 id)
 304 {
 305         union bpf_attr attr;
 306
 307         bzero(&attr, sizeof(attr));
 308         attr.map_id = id;
 309
 310         return sys_bpf(BPF_MAP_GET_FD_BY_ID, &attr, sizeof(attr));
 311 }
 312
 313 int bpf_obj_get_info_by_fd(int prog_fd, void *info, __u32 *info_len)
 314 {
 315         union bpf_attr attr;
 316         int err;
 317
 318         bzero(&attr, sizeof(attr));
 319         attr.info.bpf_fd = prog_fd;
 320         attr.info.info_len = *info_len;
 321         attr.info.info = ptr_to_u64(info);
 322
 323         err = sys_bpf(BPF_OBJ_GET_INFO_BY_FD, &attr, sizeof(attr));
 324         if (!err)
 325                 *info_len = attr.info.info_len;
 326
 327         return err;
 328 }