1 // SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) 2 // Copyright (C) 2018 Facebook 3 4 #define _GNU_SOURCE 5 #include <errno.h> 6 #include <fcntl.h> 7 #include <stdlib.h> 8 #include <string.h> 9 #include <unistd.h> 10 #include <bpf/bpf.h> 11 #include <bpf/libbpf.h> 12 #include <net/if.h> 13 #include <linux/if.h> 14 #include <linux/rtnetlink.h> 15 #include <linux/tc_act/tc_bpf.h> 16 #include <sys/socket.h> 17 #include <sys/stat.h> 18 #include <sys/types.h> 19 20 #include "bpf/nlattr.h" 21 #include "bpf/libbpf_internal.h" 22 #include "main.h" 23 #include "netlink_dumper.h" 24 25 struct ip_devname_ifindex { 26 char devname[64]; 27 int ifindex; 28 }; 29 30 struct bpf_netdev_t { 31 struct ip_devname_ifindex *devices; 32 int used_len; 33 int array_len; 34 int filter_idx; 35 }; 36 37 struct tc_kind_handle { 38 char kind[64]; 39 int handle; 40 }; 41 42 struct bpf_tcinfo_t { 43 struct tc_kind_handle *handle_array; 44 int used_len; 45 int array_len; 46 bool is_qdisc; 47 }; 48 49 struct bpf_filter_t { 50 const char *kind; 51 const char *devname; 52 int ifindex; 53 }; 54 55 struct bpf_attach_info { 56 __u32 flow_dissector_id; 57 }; 58 59 enum net_attach_type { 60 NET_ATTACH_TYPE_XDP, 61 NET_ATTACH_TYPE_XDP_GENERIC, 62 NET_ATTACH_TYPE_XDP_DRIVER, 63 NET_ATTACH_TYPE_XDP_OFFLOAD, 64 }; 65 66 static const char * const attach_type_strings[] = { 67 [NET_ATTACH_TYPE_XDP] = "xdp", 68 [NET_ATTACH_TYPE_XDP_GENERIC] = "xdpgeneric", 69 [NET_ATTACH_TYPE_XDP_DRIVER] = "xdpdrv", 70 [NET_ATTACH_TYPE_XDP_OFFLOAD] = "xdpoffload", 71 }; 72 73 const size_t net_attach_type_size = ARRAY_SIZE(attach_type_strings); 74 75 static enum net_attach_type parse_attach_type(const char *str) 76 { 77 enum net_attach_type type; 78 79 for (type = 0; type < net_attach_type_size; type++) { 80 if (attach_type_strings[type] && 81 is_prefix(str, attach_type_strings[type])) 82 return type; 83 } 84 85 return net_attach_type_size; 86 } 87 88 static int dump_link_nlmsg(void *cookie, void *msg, struct nlattr **tb) 89 { 90 struct bpf_netdev_t *netinfo = cookie; 91 struct ifinfomsg *ifinfo = msg; 92 93 if (netinfo->filter_idx > 0 && netinfo->filter_idx != ifinfo->ifi_index) 94 return 0; 95 96 if (netinfo->used_len == netinfo->array_len) { 97 netinfo->devices = realloc(netinfo->devices, 98 (netinfo->array_len + 16) * 99 sizeof(struct ip_devname_ifindex)); 100 if (!netinfo->devices) 101 return -ENOMEM; 102 103 netinfo->array_len += 16; 104 } 105 netinfo->devices[netinfo->used_len].ifindex = ifinfo->ifi_index; 106 snprintf(netinfo->devices[netinfo->used_len].devname, 107 sizeof(netinfo->devices[netinfo->used_len].devname), 108 "%s", 109 tb[IFLA_IFNAME] 110 ? libbpf_nla_getattr_str(tb[IFLA_IFNAME]) 111 : ""); 112 netinfo->used_len++; 113 114 return do_xdp_dump(ifinfo, tb); 115 } 116 117 static int dump_class_qdisc_nlmsg(void *cookie, void *msg, struct nlattr **tb) 118 { 119 struct bpf_tcinfo_t *tcinfo = cookie; 120 struct tcmsg *info = msg; 121 122 if (tcinfo->is_qdisc) { 123 /* skip clsact qdisc */ 124 if (tb[TCA_KIND] && 125 strcmp(libbpf_nla_data(tb[TCA_KIND]), "clsact") == 0) 126 return 0; 127 if (info->tcm_handle == 0) 128 return 0; 129 } 130 131 if (tcinfo->used_len == tcinfo->array_len) { 132 tcinfo->handle_array = realloc(tcinfo->handle_array, 133 (tcinfo->array_len + 16) * sizeof(struct tc_kind_handle)); 134 if (!tcinfo->handle_array) 135 return -ENOMEM; 136 137 tcinfo->array_len += 16; 138 } 139 tcinfo->handle_array[tcinfo->used_len].handle = info->tcm_handle; 140 snprintf(tcinfo->handle_array[tcinfo->used_len].kind, 141 sizeof(tcinfo->handle_array[tcinfo->used_len].kind), 142 "%s", 143 tb[TCA_KIND] 144 ? libbpf_nla_getattr_str(tb[TCA_KIND]) 145 : "unknown"); 146 tcinfo->used_len++; 147 148 return 0; 149 } 150 151 static int dump_filter_nlmsg(void *cookie, void *msg, struct nlattr **tb) 152 { 153 const struct bpf_filter_t *filter_info = cookie; 154 155 return do_filter_dump((struct tcmsg *)msg, tb, filter_info->kind, 156 filter_info->devname, filter_info->ifindex); 157 } 158 159 static int show_dev_tc_bpf(int sock, unsigned int nl_pid, 160 struct ip_devname_ifindex *dev) 161 { 162 struct bpf_filter_t filter_info; 163 struct bpf_tcinfo_t tcinfo; 164 int i, handle, ret = 0; 165 166 tcinfo.handle_array = NULL; 167 tcinfo.used_len = 0; 168 tcinfo.array_len = 0; 169 170 tcinfo.is_qdisc = false; 171 ret = libbpf_nl_get_class(sock, nl_pid, dev->ifindex, 172 dump_class_qdisc_nlmsg, &tcinfo); 173 if (ret) 174 goto out; 175 176 tcinfo.is_qdisc = true; 177 ret = libbpf_nl_get_qdisc(sock, nl_pid, dev->ifindex, 178 dump_class_qdisc_nlmsg, &tcinfo); 179 if (ret) 180 goto out; 181 182 filter_info.devname = dev->devname; 183 filter_info.ifindex = dev->ifindex; 184 for (i = 0; i < tcinfo.used_len; i++) { 185 filter_info.kind = tcinfo.handle_array[i].kind; 186 ret = libbpf_nl_get_filter(sock, nl_pid, dev->ifindex, 187 tcinfo.handle_array[i].handle, 188 dump_filter_nlmsg, &filter_info); 189 if (ret) 190 goto out; 191 } 192 193 /* root, ingress and egress handle */ 194 handle = TC_H_ROOT; 195 filter_info.kind = "root"; 196 ret = libbpf_nl_get_filter(sock, nl_pid, dev->ifindex, handle, 197 dump_filter_nlmsg, &filter_info); 198 if (ret) 199 goto out; 200 201 handle = TC_H_MAKE(TC_H_CLSACT, TC_H_MIN_INGRESS); 202 filter_info.kind = "clsact/ingress"; 203 ret = libbpf_nl_get_filter(sock, nl_pid, dev->ifindex, handle, 204 dump_filter_nlmsg, &filter_info); 205 if (ret) 206 goto out; 207 208 handle = TC_H_MAKE(TC_H_CLSACT, TC_H_MIN_EGRESS); 209 filter_info.kind = "clsact/egress"; 210 ret = libbpf_nl_get_filter(sock, nl_pid, dev->ifindex, handle, 211 dump_filter_nlmsg, &filter_info); 212 if (ret) 213 goto out; 214 215 out: 216 free(tcinfo.handle_array); 217 return 0; 218 } 219 220 static int query_flow_dissector(struct bpf_attach_info *attach_info) 221 { 222 __u32 attach_flags; 223 __u32 prog_ids[1]; 224 __u32 prog_cnt; 225 int err; 226 int fd; 227 228 fd = open("/proc/self/ns/net", O_RDONLY); 229 if (fd < 0) { 230 p_err("can't open /proc/self/ns/net: %s", 231 strerror(errno)); 232 return -1; 233 } 234 prog_cnt = ARRAY_SIZE(prog_ids); 235 err = bpf_prog_query(fd, BPF_FLOW_DISSECTOR, 0, 236 &attach_flags, prog_ids, &prog_cnt); 237 close(fd); 238 if (err) { 239 if (errno == EINVAL) { 240 /* Older kernel's don't support querying 241 * flow dissector programs. 242 */ 243 errno = 0; 244 return 0; 245 } 246 p_err("can't query prog: %s", strerror(errno)); 247 return -1; 248 } 249 250 if (prog_cnt == 1) 251 attach_info->flow_dissector_id = prog_ids[0]; 252 253 return 0; 254 } 255 256 static int net_parse_dev(int *argc, char ***argv) 257 { 258 int ifindex; 259 260 if (is_prefix(**argv, "dev")) { 261 NEXT_ARGP(); 262 263 ifindex = if_nametoindex(**argv); 264 if (!ifindex) 265 p_err("invalid devname %s", **argv); 266 267 NEXT_ARGP(); 268 } else { 269 p_err("expected 'dev', got: '%s'?", **argv); 270 return -1; 271 } 272 273 return ifindex; 274 } 275 276 static int do_attach_detach_xdp(int progfd, enum net_attach_type attach_type, 277 int ifindex, bool overwrite) 278 { 279 __u32 flags = 0; 280 281 if (!overwrite) 282 flags = XDP_FLAGS_UPDATE_IF_NOEXIST; 283 if (attach_type == NET_ATTACH_TYPE_XDP_GENERIC) 284 flags |= XDP_FLAGS_SKB_MODE; 285 if (attach_type == NET_ATTACH_TYPE_XDP_DRIVER) 286 flags |= XDP_FLAGS_DRV_MODE; 287 if (attach_type == NET_ATTACH_TYPE_XDP_OFFLOAD) 288 flags |= XDP_FLAGS_HW_MODE; 289 290 return bpf_set_link_xdp_fd(ifindex, progfd, flags); 291 } 292 293 static int do_attach(int argc, char **argv) 294 { 295 enum net_attach_type attach_type; 296 int progfd, ifindex, err = 0; 297 bool overwrite = false; 298 299 /* parse attach args */ 300 if (!REQ_ARGS(5)) 301 return -EINVAL; 302 303 attach_type = parse_attach_type(*argv); 304 if (attach_type == net_attach_type_size) { 305 p_err("invalid net attach/detach type: %s", *argv); 306 return -EINVAL; 307 } 308 NEXT_ARG(); 309 310 progfd = prog_parse_fd(&argc, &argv); 311 if (progfd < 0) 312 return -EINVAL; 313 314 ifindex = net_parse_dev(&argc, &argv); 315 if (ifindex < 1) { 316 close(progfd); 317 return -EINVAL; 318 } 319 320 if (argc) { 321 if (is_prefix(*argv, "overwrite")) { 322 overwrite = true; 323 } else { 324 p_err("expected 'overwrite', got: '%s'?", *argv); 325 close(progfd); 326 return -EINVAL; 327 } 328 } 329 330 /* attach xdp prog */ 331 if (is_prefix("xdp", attach_type_strings[attach_type])) 332 err = do_attach_detach_xdp(progfd, attach_type, ifindex, 333 overwrite); 334 335 if (err < 0) { 336 p_err("interface %s attach failed: %s", 337 attach_type_strings[attach_type], strerror(-err)); 338 return err; 339 } 340 341 if (json_output) 342 jsonw_null(json_wtr); 343 344 return 0; 345 } 346 347 static int do_detach(int argc, char **argv) 348 { 349 enum net_attach_type attach_type; 350 int progfd, ifindex, err = 0; 351 352 /* parse detach args */ 353 if (!REQ_ARGS(3)) 354 return -EINVAL; 355 356 attach_type = parse_attach_type(*argv); 357 if (attach_type == net_attach_type_size) { 358 p_err("invalid net attach/detach type: %s", *argv); 359 return -EINVAL; 360 } 361 NEXT_ARG(); 362 363 ifindex = net_parse_dev(&argc, &argv); 364 if (ifindex < 1) 365 return -EINVAL; 366 367 /* detach xdp prog */ 368 progfd = -1; 369 if (is_prefix("xdp", attach_type_strings[attach_type])) 370 err = do_attach_detach_xdp(progfd, attach_type, ifindex, NULL); 371 372 if (err < 0) { 373 p_err("interface %s detach failed: %s", 374 attach_type_strings[attach_type], strerror(-err)); 375 return err; 376 } 377 378 if (json_output) 379 jsonw_null(json_wtr); 380 381 return 0; 382 } 383 384 static int do_show(int argc, char **argv) 385 { 386 struct bpf_attach_info attach_info = {}; 387 int i, sock, ret, filter_idx = -1; 388 struct bpf_netdev_t dev_array; 389 unsigned int nl_pid; 390 char err_buf[256]; 391 392 if (argc == 2) { 393 filter_idx = net_parse_dev(&argc, &argv); 394 if (filter_idx < 1) 395 return -1; 396 } else if (argc != 0) { 397 usage(); 398 } 399 400 ret = query_flow_dissector(&attach_info); 401 if (ret) 402 return -1; 403 404 sock = libbpf_netlink_open(&nl_pid); 405 if (sock < 0) { 406 fprintf(stderr, "failed to open netlink sock\n"); 407 return -1; 408 } 409 410 dev_array.devices = NULL; 411 dev_array.used_len = 0; 412 dev_array.array_len = 0; 413 dev_array.filter_idx = filter_idx; 414 415 if (json_output) 416 jsonw_start_array(json_wtr); 417 NET_START_OBJECT; 418 NET_START_ARRAY("xdp", "%s:\n"); 419 ret = libbpf_nl_get_link(sock, nl_pid, dump_link_nlmsg, &dev_array); 420 NET_END_ARRAY("\n"); 421 422 if (!ret) { 423 NET_START_ARRAY("tc", "%s:\n"); 424 for (i = 0; i < dev_array.used_len; i++) { 425 ret = show_dev_tc_bpf(sock, nl_pid, 426 &dev_array.devices[i]); 427 if (ret) 428 break; 429 } 430 NET_END_ARRAY("\n"); 431 } 432 433 NET_START_ARRAY("flow_dissector", "%s:\n"); 434 if (attach_info.flow_dissector_id > 0) 435 NET_DUMP_UINT("id", "id %u", attach_info.flow_dissector_id); 436 NET_END_ARRAY("\n"); 437 438 NET_END_OBJECT; 439 if (json_output) 440 jsonw_end_array(json_wtr); 441 442 if (ret) { 443 if (json_output) 444 jsonw_null(json_wtr); 445 libbpf_strerror(ret, err_buf, sizeof(err_buf)); 446 fprintf(stderr, "Error: %s\n", err_buf); 447 } 448 free(dev_array.devices); 449 close(sock); 450 return ret; 451 } 452 453 static int do_help(int argc, char **argv) 454 { 455 if (json_output) { 456 jsonw_null(json_wtr); 457 return 0; 458 } 459 460 fprintf(stderr, 461 "Usage: %1$s %2$s { show | list } [dev <devname>]\n" 462 " %1$s %2$s attach ATTACH_TYPE PROG dev <devname> [ overwrite ]\n" 463 " %1$s %2$s detach ATTACH_TYPE dev <devname>\n" 464 " %1$s %2$s help\n" 465 "\n" 466 " " HELP_SPEC_PROGRAM "\n" 467 " ATTACH_TYPE := { xdp | xdpgeneric | xdpdrv | xdpoffload }\n" 468 "\n" 469 "Note: Only xdp and tc attachments are supported now.\n" 470 " For progs attached to cgroups, use \"bpftool cgroup\"\n" 471 " to dump program attachments. For program types\n" 472 " sk_{filter,skb,msg,reuseport} and lwt/seg6, please\n" 473 " consult iproute2.\n" 474 "", 475 bin_name, argv[-2]); 476 477 return 0; 478 } 479 480 static const struct cmd cmds[] = { 481 { "show", do_show }, 482 { "list", do_show }, 483 { "attach", do_attach }, 484 { "detach", do_detach }, 485 { "help", do_help }, 486 { 0 } 487 }; 488 489 int do_net(int argc, char **argv) 490 { 491 return cmd_select(cmds, argc, argv, do_help); 492 } 493