1 // SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) 2 /* Copyright (C) 2020 Facebook */ 3 4 #include <errno.h> 5 #include <linux/err.h> 6 #include <linux/netfilter.h> 7 #include <linux/netfilter_arp.h> 8 #include <net/if.h> 9 #include <stdio.h> 10 #include <unistd.h> 11 12 #include <bpf/bpf.h> 13 #include <bpf/hashmap.h> 14 15 #include "json_writer.h" 16 #include "main.h" 17 18 static struct hashmap *link_table; 19 20 static int link_parse_fd(int *argc, char ***argv) 21 { 22 int fd; 23 24 if (is_prefix(**argv, "id")) { 25 unsigned int id; 26 char *endptr; 27 28 NEXT_ARGP(); 29 30 id = strtoul(**argv, &endptr, 0); 31 if (*endptr) { 32 p_err("can't parse %s as ID", **argv); 33 return -1; 34 } 35 NEXT_ARGP(); 36 37 fd = bpf_link_get_fd_by_id(id); 38 if (fd < 0) 39 p_err("failed to get link with ID %d: %s", id, strerror(errno)); 40 return fd; 41 } else if (is_prefix(**argv, "pinned")) { 42 char *path; 43 44 NEXT_ARGP(); 45 46 path = **argv; 47 NEXT_ARGP(); 48 49 return open_obj_pinned_any(path, BPF_OBJ_LINK); 50 } 51 52 p_err("expected 'id' or 'pinned', got: '%s'?", **argv); 53 return -1; 54 } 55 56 static void 57 show_link_header_json(struct bpf_link_info *info, json_writer_t *wtr) 58 { 59 const char *link_type_str; 60 61 jsonw_uint_field(wtr, "id", info->id); 62 link_type_str = libbpf_bpf_link_type_str(info->type); 63 if (link_type_str) 64 jsonw_string_field(wtr, "type", link_type_str); 65 else 66 jsonw_uint_field(wtr, "type", info->type); 67 68 jsonw_uint_field(json_wtr, "prog_id", info->prog_id); 69 } 70 71 static void show_link_attach_type_json(__u32 attach_type, json_writer_t *wtr) 72 { 73 const char *attach_type_str; 74 75 attach_type_str = libbpf_bpf_attach_type_str(attach_type); 76 if (attach_type_str) 77 jsonw_string_field(wtr, "attach_type", attach_type_str); 78 else 79 jsonw_uint_field(wtr, "attach_type", attach_type); 80 } 81 82 static bool is_iter_map_target(const char *target_name) 83 { 84 return strcmp(target_name, "bpf_map_elem") == 0 || 85 strcmp(target_name, "bpf_sk_storage_map") == 0; 86 } 87 88 static bool is_iter_cgroup_target(const char *target_name) 89 { 90 return strcmp(target_name, "cgroup") == 0; 91 } 92 93 static const char *cgroup_order_string(__u32 order) 94 { 95 switch (order) { 96 case BPF_CGROUP_ITER_ORDER_UNSPEC: 97 return "order_unspec"; 98 case BPF_CGROUP_ITER_SELF_ONLY: 99 return "self_only"; 100 case BPF_CGROUP_ITER_DESCENDANTS_PRE: 101 return "descendants_pre"; 102 case BPF_CGROUP_ITER_DESCENDANTS_POST: 103 return "descendants_post"; 104 case BPF_CGROUP_ITER_ANCESTORS_UP: 105 return "ancestors_up"; 106 default: /* won't happen */ 107 return "unknown"; 108 } 109 } 110 111 static bool is_iter_task_target(const char *target_name) 112 { 113 return strcmp(target_name, "task") == 0 || 114 strcmp(target_name, "task_file") == 0 || 115 strcmp(target_name, "task_vma") == 0; 116 } 117 118 static void show_iter_json(struct bpf_link_info *info, json_writer_t *wtr) 119 { 120 const char *target_name = u64_to_ptr(info->iter.target_name); 121 122 jsonw_string_field(wtr, "target_name", target_name); 123 124 if (is_iter_map_target(target_name)) 125 jsonw_uint_field(wtr, "map_id", info->iter.map.map_id); 126 else if (is_iter_task_target(target_name)) { 127 if (info->iter.task.tid) 128 jsonw_uint_field(wtr, "tid", info->iter.task.tid); 129 else if (info->iter.task.pid) 130 jsonw_uint_field(wtr, "pid", info->iter.task.pid); 131 } 132 133 if (is_iter_cgroup_target(target_name)) { 134 jsonw_lluint_field(wtr, "cgroup_id", info->iter.cgroup.cgroup_id); 135 jsonw_string_field(wtr, "order", 136 cgroup_order_string(info->iter.cgroup.order)); 137 } 138 } 139 140 void netfilter_dump_json(const struct bpf_link_info *info, json_writer_t *wtr) 141 { 142 jsonw_uint_field(json_wtr, "pf", 143 info->netfilter.pf); 144 jsonw_uint_field(json_wtr, "hook", 145 info->netfilter.hooknum); 146 jsonw_int_field(json_wtr, "prio", 147 info->netfilter.priority); 148 jsonw_uint_field(json_wtr, "flags", 149 info->netfilter.flags); 150 } 151 152 static int get_prog_info(int prog_id, struct bpf_prog_info *info) 153 { 154 __u32 len = sizeof(*info); 155 int err, prog_fd; 156 157 prog_fd = bpf_prog_get_fd_by_id(prog_id); 158 if (prog_fd < 0) 159 return prog_fd; 160 161 memset(info, 0, sizeof(*info)); 162 err = bpf_prog_get_info_by_fd(prog_fd, info, &len); 163 if (err) 164 p_err("can't get prog info: %s", strerror(errno)); 165 close(prog_fd); 166 return err; 167 } 168 169 static int show_link_close_json(int fd, struct bpf_link_info *info) 170 { 171 struct bpf_prog_info prog_info; 172 const char *prog_type_str; 173 int err; 174 175 jsonw_start_object(json_wtr); 176 177 show_link_header_json(info, json_wtr); 178 179 switch (info->type) { 180 case BPF_LINK_TYPE_RAW_TRACEPOINT: 181 jsonw_string_field(json_wtr, "tp_name", 182 u64_to_ptr(info->raw_tracepoint.tp_name)); 183 break; 184 case BPF_LINK_TYPE_TRACING: 185 err = get_prog_info(info->prog_id, &prog_info); 186 if (err) 187 return err; 188 189 prog_type_str = libbpf_bpf_prog_type_str(prog_info.type); 190 /* libbpf will return NULL for variants unknown to it. */ 191 if (prog_type_str) 192 jsonw_string_field(json_wtr, "prog_type", prog_type_str); 193 else 194 jsonw_uint_field(json_wtr, "prog_type", prog_info.type); 195 196 show_link_attach_type_json(info->tracing.attach_type, 197 json_wtr); 198 break; 199 case BPF_LINK_TYPE_CGROUP: 200 jsonw_lluint_field(json_wtr, "cgroup_id", 201 info->cgroup.cgroup_id); 202 show_link_attach_type_json(info->cgroup.attach_type, json_wtr); 203 break; 204 case BPF_LINK_TYPE_ITER: 205 show_iter_json(info, json_wtr); 206 break; 207 case BPF_LINK_TYPE_NETNS: 208 jsonw_uint_field(json_wtr, "netns_ino", 209 info->netns.netns_ino); 210 show_link_attach_type_json(info->netns.attach_type, json_wtr); 211 break; 212 case BPF_LINK_TYPE_NETFILTER: 213 netfilter_dump_json(info, json_wtr); 214 break; 215 216 default: 217 break; 218 } 219 220 if (!hashmap__empty(link_table)) { 221 struct hashmap_entry *entry; 222 223 jsonw_name(json_wtr, "pinned"); 224 jsonw_start_array(json_wtr); 225 hashmap__for_each_key_entry(link_table, entry, info->id) 226 jsonw_string(json_wtr, entry->pvalue); 227 jsonw_end_array(json_wtr); 228 } 229 230 emit_obj_refs_json(refs_table, info->id, json_wtr); 231 232 jsonw_end_object(json_wtr); 233 234 return 0; 235 } 236 237 static void show_link_header_plain(struct bpf_link_info *info) 238 { 239 const char *link_type_str; 240 241 printf("%u: ", info->id); 242 link_type_str = libbpf_bpf_link_type_str(info->type); 243 if (link_type_str) 244 printf("%s ", link_type_str); 245 else 246 printf("type %u ", info->type); 247 248 printf("prog %u ", info->prog_id); 249 } 250 251 static void show_link_attach_type_plain(__u32 attach_type) 252 { 253 const char *attach_type_str; 254 255 attach_type_str = libbpf_bpf_attach_type_str(attach_type); 256 if (attach_type_str) 257 printf("attach_type %s ", attach_type_str); 258 else 259 printf("attach_type %u ", attach_type); 260 } 261 262 static void show_iter_plain(struct bpf_link_info *info) 263 { 264 const char *target_name = u64_to_ptr(info->iter.target_name); 265 266 printf("target_name %s ", target_name); 267 268 if (is_iter_map_target(target_name)) 269 printf("map_id %u ", info->iter.map.map_id); 270 else if (is_iter_task_target(target_name)) { 271 if (info->iter.task.tid) 272 printf("tid %u ", info->iter.task.tid); 273 else if (info->iter.task.pid) 274 printf("pid %u ", info->iter.task.pid); 275 } 276 277 if (is_iter_cgroup_target(target_name)) { 278 printf("cgroup_id %llu ", info->iter.cgroup.cgroup_id); 279 printf("order %s ", 280 cgroup_order_string(info->iter.cgroup.order)); 281 } 282 } 283 284 static const char * const pf2name[] = { 285 [NFPROTO_INET] = "inet", 286 [NFPROTO_IPV4] = "ip", 287 [NFPROTO_ARP] = "arp", 288 [NFPROTO_NETDEV] = "netdev", 289 [NFPROTO_BRIDGE] = "bridge", 290 [NFPROTO_IPV6] = "ip6", 291 }; 292 293 static const char * const inethook2name[] = { 294 [NF_INET_PRE_ROUTING] = "prerouting", 295 [NF_INET_LOCAL_IN] = "input", 296 [NF_INET_FORWARD] = "forward", 297 [NF_INET_LOCAL_OUT] = "output", 298 [NF_INET_POST_ROUTING] = "postrouting", 299 }; 300 301 static const char * const arphook2name[] = { 302 [NF_ARP_IN] = "input", 303 [NF_ARP_OUT] = "output", 304 }; 305 306 void netfilter_dump_plain(const struct bpf_link_info *info) 307 { 308 const char *hookname = NULL, *pfname = NULL; 309 unsigned int hook = info->netfilter.hooknum; 310 unsigned int pf = info->netfilter.pf; 311 312 if (pf < ARRAY_SIZE(pf2name)) 313 pfname = pf2name[pf]; 314 315 switch (pf) { 316 case NFPROTO_BRIDGE: /* bridge shares numbers with enum nf_inet_hooks */ 317 case NFPROTO_IPV4: 318 case NFPROTO_IPV6: 319 case NFPROTO_INET: 320 if (hook < ARRAY_SIZE(inethook2name)) 321 hookname = inethook2name[hook]; 322 break; 323 case NFPROTO_ARP: 324 if (hook < ARRAY_SIZE(arphook2name)) 325 hookname = arphook2name[hook]; 326 default: 327 break; 328 } 329 330 if (pfname) 331 printf("\n\t%s", pfname); 332 else 333 printf("\n\tpf: %d", pf); 334 335 if (hookname) 336 printf(" %s", hookname); 337 else 338 printf(", hook %u,", hook); 339 340 printf(" prio %d", info->netfilter.priority); 341 342 if (info->netfilter.flags) 343 printf(" flags 0x%x", info->netfilter.flags); 344 } 345 346 static int show_link_close_plain(int fd, struct bpf_link_info *info) 347 { 348 struct bpf_prog_info prog_info; 349 const char *prog_type_str; 350 int err; 351 352 show_link_header_plain(info); 353 354 switch (info->type) { 355 case BPF_LINK_TYPE_RAW_TRACEPOINT: 356 printf("\n\ttp '%s' ", 357 (const char *)u64_to_ptr(info->raw_tracepoint.tp_name)); 358 break; 359 case BPF_LINK_TYPE_TRACING: 360 err = get_prog_info(info->prog_id, &prog_info); 361 if (err) 362 return err; 363 364 prog_type_str = libbpf_bpf_prog_type_str(prog_info.type); 365 /* libbpf will return NULL for variants unknown to it. */ 366 if (prog_type_str) 367 printf("\n\tprog_type %s ", prog_type_str); 368 else 369 printf("\n\tprog_type %u ", prog_info.type); 370 371 show_link_attach_type_plain(info->tracing.attach_type); 372 break; 373 case BPF_LINK_TYPE_CGROUP: 374 printf("\n\tcgroup_id %zu ", (size_t)info->cgroup.cgroup_id); 375 show_link_attach_type_plain(info->cgroup.attach_type); 376 break; 377 case BPF_LINK_TYPE_ITER: 378 show_iter_plain(info); 379 break; 380 case BPF_LINK_TYPE_NETNS: 381 printf("\n\tnetns_ino %u ", info->netns.netns_ino); 382 show_link_attach_type_plain(info->netns.attach_type); 383 break; 384 case BPF_LINK_TYPE_NETFILTER: 385 netfilter_dump_plain(info); 386 break; 387 default: 388 break; 389 } 390 391 if (!hashmap__empty(link_table)) { 392 struct hashmap_entry *entry; 393 394 hashmap__for_each_key_entry(link_table, entry, info->id) 395 printf("\n\tpinned %s", (char *)entry->pvalue); 396 } 397 emit_obj_refs_plain(refs_table, info->id, "\n\tpids "); 398 399 printf("\n"); 400 401 return 0; 402 } 403 404 static int do_show_link(int fd) 405 { 406 struct bpf_link_info info; 407 __u32 len = sizeof(info); 408 char buf[256]; 409 int err; 410 411 memset(&info, 0, sizeof(info)); 412 again: 413 err = bpf_link_get_info_by_fd(fd, &info, &len); 414 if (err) { 415 p_err("can't get link info: %s", 416 strerror(errno)); 417 close(fd); 418 return err; 419 } 420 if (info.type == BPF_LINK_TYPE_RAW_TRACEPOINT && 421 !info.raw_tracepoint.tp_name) { 422 info.raw_tracepoint.tp_name = (unsigned long)&buf; 423 info.raw_tracepoint.tp_name_len = sizeof(buf); 424 goto again; 425 } 426 if (info.type == BPF_LINK_TYPE_ITER && 427 !info.iter.target_name) { 428 info.iter.target_name = (unsigned long)&buf; 429 info.iter.target_name_len = sizeof(buf); 430 goto again; 431 } 432 433 if (json_output) 434 show_link_close_json(fd, &info); 435 else 436 show_link_close_plain(fd, &info); 437 438 close(fd); 439 return 0; 440 } 441 442 static int do_show(int argc, char **argv) 443 { 444 __u32 id = 0; 445 int err, fd; 446 447 if (show_pinned) { 448 link_table = hashmap__new(hash_fn_for_key_as_id, 449 equal_fn_for_key_as_id, NULL); 450 if (IS_ERR(link_table)) { 451 p_err("failed to create hashmap for pinned paths"); 452 return -1; 453 } 454 build_pinned_obj_table(link_table, BPF_OBJ_LINK); 455 } 456 build_obj_refs_table(&refs_table, BPF_OBJ_LINK); 457 458 if (argc == 2) { 459 fd = link_parse_fd(&argc, &argv); 460 if (fd < 0) 461 return fd; 462 return do_show_link(fd); 463 } 464 465 if (argc) 466 return BAD_ARG(); 467 468 if (json_output) 469 jsonw_start_array(json_wtr); 470 while (true) { 471 err = bpf_link_get_next_id(id, &id); 472 if (err) { 473 if (errno == ENOENT) 474 break; 475 p_err("can't get next link: %s%s", strerror(errno), 476 errno == EINVAL ? " -- kernel too old?" : ""); 477 break; 478 } 479 480 fd = bpf_link_get_fd_by_id(id); 481 if (fd < 0) { 482 if (errno == ENOENT) 483 continue; 484 p_err("can't get link by id (%u): %s", 485 id, strerror(errno)); 486 break; 487 } 488 489 err = do_show_link(fd); 490 if (err) 491 break; 492 } 493 if (json_output) 494 jsonw_end_array(json_wtr); 495 496 delete_obj_refs_table(refs_table); 497 498 if (show_pinned) 499 delete_pinned_obj_table(link_table); 500 501 return errno == ENOENT ? 0 : -1; 502 } 503 504 static int do_pin(int argc, char **argv) 505 { 506 int err; 507 508 err = do_pin_any(argc, argv, link_parse_fd); 509 if (!err && json_output) 510 jsonw_null(json_wtr); 511 return err; 512 } 513 514 static int do_detach(int argc, char **argv) 515 { 516 int err, fd; 517 518 if (argc != 2) { 519 p_err("link specifier is invalid or missing\n"); 520 return 1; 521 } 522 523 fd = link_parse_fd(&argc, &argv); 524 if (fd < 0) 525 return 1; 526 527 err = bpf_link_detach(fd); 528 if (err) 529 err = -errno; 530 close(fd); 531 if (err) { 532 p_err("failed link detach: %s", strerror(-err)); 533 return 1; 534 } 535 536 if (json_output) 537 jsonw_null(json_wtr); 538 539 return 0; 540 } 541 542 static int do_help(int argc, char **argv) 543 { 544 if (json_output) { 545 jsonw_null(json_wtr); 546 return 0; 547 } 548 549 fprintf(stderr, 550 "Usage: %1$s %2$s { show | list } [LINK]\n" 551 " %1$s %2$s pin LINK FILE\n" 552 " %1$s %2$s detach LINK\n" 553 " %1$s %2$s help\n" 554 "\n" 555 " " HELP_SPEC_LINK "\n" 556 " " HELP_SPEC_OPTIONS " |\n" 557 " {-f|--bpffs} | {-n|--nomount} }\n" 558 "", 559 bin_name, argv[-2]); 560 561 return 0; 562 } 563 564 static const struct cmd cmds[] = { 565 { "show", do_show }, 566 { "list", do_show }, 567 { "help", do_help }, 568 { "pin", do_pin }, 569 { "detach", do_detach }, 570 { 0 } 571 }; 572 573 int do_link(int argc, char **argv) 574 { 575 return cmd_select(cmds, argc, argv, do_help); 576 } 577