tools/bpf/bpftool/net.c

   1 // SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
   2 // Copyright (C) 2018 Facebook
   3
   4 #ifndef _GNU_SOURCE
   5 #define _GNU_SOURCE
   6 #endif
   7 #include <errno.h>
   8 #include <fcntl.h>
   9 #include <stdlib.h>
  10 #include <string.h>
  11 #include <time.h>
  12 #include <unistd.h>
  13 #include <bpf/bpf.h>
  14 #include <bpf/libbpf.h>
  15 #include <net/if.h>
  16 #include <linux/rtnetlink.h>
  17 #include <linux/socket.h>
  18 #include <linux/tc_act/tc_bpf.h>
  19 #include <sys/socket.h>
  20 #include <sys/stat.h>
  21 #include <sys/types.h>
  22
  23 #include "bpf/nlattr.h"
  24 #include "main.h"
  25 #include "netlink_dumper.h"
  26
  27 #ifndef SOL_NETLINK
  28 #define SOL_NETLINK 270
  29 #endif
  30
  31 struct ip_devname_ifindex {
  32         char    devname[64];
  33         int     ifindex;
  34 };
  35
  36 struct bpf_netdev_t {
  37         struct ip_devname_ifindex *devices;
  38         int     used_len;
  39         int     array_len;
  40         int     filter_idx;
  41 };
  42
  43 struct tc_kind_handle {
  44         char    kind[64];
  45         int     handle;
  46 };
  47
  48 struct bpf_tcinfo_t {
  49         struct tc_kind_handle   *handle_array;
  50         int                     used_len;
  51         int                     array_len;
  52         bool                    is_qdisc;
  53 };
  54
  55 struct bpf_filter_t {
  56         const char      *kind;
  57         const char      *devname;
  58         int             ifindex;
  59 };
  60
  61 struct bpf_attach_info {
  62         __u32 flow_dissector_id;
  63 };
  64
  65 enum net_attach_type {
  66         NET_ATTACH_TYPE_XDP,
  67         NET_ATTACH_TYPE_XDP_GENERIC,
  68         NET_ATTACH_TYPE_XDP_DRIVER,
  69         NET_ATTACH_TYPE_XDP_OFFLOAD,
  70 };
  71
  72 static const char * const attach_type_strings[] = {
  73         [NET_ATTACH_TYPE_XDP]           = "xdp",
  74         [NET_ATTACH_TYPE_XDP_GENERIC]   = "xdpgeneric",
  75         [NET_ATTACH_TYPE_XDP_DRIVER]    = "xdpdrv",
  76         [NET_ATTACH_TYPE_XDP_OFFLOAD]   = "xdpoffload",
  77 };
  78
  79 const size_t net_attach_type_size = ARRAY_SIZE(attach_type_strings);
  80
  81 static enum net_attach_type parse_attach_type(const char *str)
  82 {
  83         enum net_attach_type type;
  84
  85         for (type = 0; type < net_attach_type_size; type++) {
  86                 if (attach_type_strings[type] &&
  87                     is_prefix(str, attach_type_strings[type]))
  88                         return type;
  89         }
  90
  91         return net_attach_type_size;
  92 }
  93
  94 typedef int (*dump_nlmsg_t)(void *cookie, void *msg, struct nlattr **tb);
  95
  96 typedef int (*__dump_nlmsg_t)(struct nlmsghdr *nlmsg, dump_nlmsg_t, void *cookie);
  97
  98 static int netlink_open(__u32 *nl_pid)
  99 {
 100         struct sockaddr_nl sa;
 101         socklen_t addrlen;
 102         int one = 1, ret;
 103         int sock;
 104
 105         memset(&sa, 0, sizeof(sa));
 106         sa.nl_family = AF_NETLINK;
 107
 108         sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
 109         if (sock < 0)
 110                 return -errno;
 111
 112         if (setsockopt(sock, SOL_NETLINK, NETLINK_EXT_ACK,
 113                        &one, sizeof(one)) < 0) {
 114                 p_err("Netlink error reporting not supported");
 115         }
 116
 117         if (bind(sock, (struct sockaddr *)&sa, sizeof(sa)) < 0) {
 118                 ret = -errno;
 119                 goto cleanup;
 120         }
 121
 122         addrlen = sizeof(sa);
 123         if (getsockname(sock, (struct sockaddr *)&sa, &addrlen) < 0) {
 124                 ret = -errno;
 125                 goto cleanup;
 126         }
 127
 128         if (addrlen != sizeof(sa)) {
 129                 ret = -LIBBPF_ERRNO__INTERNAL;
 130                 goto cleanup;
 131         }
 132
 133         *nl_pid = sa.nl_pid;
 134         return sock;
 135
 136 cleanup:
 137         close(sock);
 138         return ret;
 139 }
 140
 141 static int netlink_recv(int sock, __u32 nl_pid, __u32 seq,
 142                             __dump_nlmsg_t _fn, dump_nlmsg_t fn,
 143                             void *cookie)
 144 {
 145         bool multipart = true;
 146         struct nlmsgerr *err;
 147         struct nlmsghdr *nh;
 148         char buf[4096];
 149         int len, ret;
 150
 151         while (multipart) {
 152                 multipart = false;
 153                 len = recv(sock, buf, sizeof(buf), 0);
 154                 if (len < 0) {
 155                         ret = -errno;
 156                         goto done;
 157                 }
 158
 159                 if (len == 0)
 160                         break;
 161
 162                 for (nh = (struct nlmsghdr *)buf; NLMSG_OK(nh, (unsigned int)len);
 163                      nh = NLMSG_NEXT(nh, len)) {
 164                         if (nh->nlmsg_pid != nl_pid) {
 165                                 ret = -LIBBPF_ERRNO__WRNGPID;
 166                                 goto done;
 167                         }
 168                         if (nh->nlmsg_seq != seq) {
 169                                 ret = -LIBBPF_ERRNO__INVSEQ;
 170                                 goto done;
 171                         }
 172                         if (nh->nlmsg_flags & NLM_F_MULTI)
 173                                 multipart = true;
 174                         switch (nh->nlmsg_type) {
 175                         case NLMSG_ERROR:
 176                                 err = (struct nlmsgerr *)NLMSG_DATA(nh);
 177                                 if (!err->error)
 178                                         continue;
 179                                 ret = err->error;
 180                                 libbpf_nla_dump_errormsg(nh);
 181                                 goto done;
 182                         case NLMSG_DONE:
 183                                 return 0;
 184                         default:
 185                                 break;
 186                         }
 187                         if (_fn) {
 188                                 ret = _fn(nh, fn, cookie);
 189                                 if (ret)
 190                                         return ret;
 191                         }
 192                 }
 193         }
 194         ret = 0;
 195 done:
 196         return ret;
 197 }
 198
 199 static int __dump_class_nlmsg(struct nlmsghdr *nlh,
 200                               dump_nlmsg_t dump_class_nlmsg,
 201                               void *cookie)
 202 {
 203         struct nlattr *tb[TCA_MAX + 1], *attr;
 204         struct tcmsg *t = NLMSG_DATA(nlh);
 205         int len;
 206
 207         len = nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*t));
 208         attr = (struct nlattr *) ((void *) t + NLMSG_ALIGN(sizeof(*t)));
 209         if (libbpf_nla_parse(tb, TCA_MAX, attr, len, NULL) != 0)
 210                 return -LIBBPF_ERRNO__NLPARSE;
 211
 212         return dump_class_nlmsg(cookie, t, tb);
 213 }
 214
 215 static int netlink_get_class(int sock, unsigned int nl_pid, int ifindex,
 216                              dump_nlmsg_t dump_class_nlmsg, void *cookie)
 217 {
 218         struct {
 219                 struct nlmsghdr nlh;
 220                 struct tcmsg t;
 221         } req = {
 222                 .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct tcmsg)),
 223                 .nlh.nlmsg_type = RTM_GETTCLASS,
 224                 .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
 225                 .t.tcm_family = AF_UNSPEC,
 226                 .t.tcm_ifindex = ifindex,
 227         };
 228         int seq = time(NULL);
 229
 230         req.nlh.nlmsg_seq = seq;
 231         if (send(sock, &req, req.nlh.nlmsg_len, 0) < 0)
 232                 return -errno;
 233
 234         return netlink_recv(sock, nl_pid, seq, __dump_class_nlmsg,
 235                             dump_class_nlmsg, cookie);
 236 }
 237
 238 static int __dump_qdisc_nlmsg(struct nlmsghdr *nlh,
 239                               dump_nlmsg_t dump_qdisc_nlmsg,
 240                               void *cookie)
 241 {
 242         struct nlattr *tb[TCA_MAX + 1], *attr;
 243         struct tcmsg *t = NLMSG_DATA(nlh);
 244         int len;
 245
 246         len = nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*t));
 247         attr = (struct nlattr *) ((void *) t + NLMSG_ALIGN(sizeof(*t)));
 248         if (libbpf_nla_parse(tb, TCA_MAX, attr, len, NULL) != 0)
 249                 return -LIBBPF_ERRNO__NLPARSE;
 250
 251         return dump_qdisc_nlmsg(cookie, t, tb);
 252 }
 253
 254 static int netlink_get_qdisc(int sock, unsigned int nl_pid, int ifindex,
 255                              dump_nlmsg_t dump_qdisc_nlmsg, void *cookie)
 256 {
 257         struct {
 258                 struct nlmsghdr nlh;
 259                 struct tcmsg t;
 260         } req = {
 261                 .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct tcmsg)),
 262                 .nlh.nlmsg_type = RTM_GETQDISC,
 263                 .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
 264                 .t.tcm_family = AF_UNSPEC,
 265                 .t.tcm_ifindex = ifindex,
 266         };
 267         int seq = time(NULL);
 268
 269         req.nlh.nlmsg_seq = seq;
 270         if (send(sock, &req, req.nlh.nlmsg_len, 0) < 0)
 271                 return -errno;
 272
 273         return netlink_recv(sock, nl_pid, seq, __dump_qdisc_nlmsg,
 274                             dump_qdisc_nlmsg, cookie);
 275 }
 276
 277 static int __dump_filter_nlmsg(struct nlmsghdr *nlh,
 278                                dump_nlmsg_t dump_filter_nlmsg,
 279                                void *cookie)
 280 {
 281         struct nlattr *tb[TCA_MAX + 1], *attr;
 282         struct tcmsg *t = NLMSG_DATA(nlh);
 283         int len;
 284
 285         len = nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*t));
 286         attr = (struct nlattr *) ((void *) t + NLMSG_ALIGN(sizeof(*t)));
 287         if (libbpf_nla_parse(tb, TCA_MAX, attr, len, NULL) != 0)
 288                 return -LIBBPF_ERRNO__NLPARSE;
 289
 290         return dump_filter_nlmsg(cookie, t, tb);
 291 }
 292
 293 static int netlink_get_filter(int sock, unsigned int nl_pid, int ifindex, int handle,
 294                               dump_nlmsg_t dump_filter_nlmsg, void *cookie)
 295 {
 296         struct {
 297                 struct nlmsghdr nlh;
 298                 struct tcmsg t;
 299         } req = {
 300                 .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct tcmsg)),
 301                 .nlh.nlmsg_type = RTM_GETTFILTER,
 302                 .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
 303                 .t.tcm_family = AF_UNSPEC,
 304                 .t.tcm_ifindex = ifindex,
 305                 .t.tcm_parent = handle,
 306         };
 307         int seq = time(NULL);
 308
 309         req.nlh.nlmsg_seq = seq;
 310         if (send(sock, &req, req.nlh.nlmsg_len, 0) < 0)
 311                 return -errno;
 312
 313         return netlink_recv(sock, nl_pid, seq, __dump_filter_nlmsg,
 314                             dump_filter_nlmsg, cookie);
 315 }
 316
 317 static int __dump_link_nlmsg(struct nlmsghdr *nlh,
 318                              dump_nlmsg_t dump_link_nlmsg, void *cookie)
 319 {
 320         struct nlattr *tb[IFLA_MAX + 1], *attr;
 321         struct ifinfomsg *ifi = NLMSG_DATA(nlh);
 322         int len;
 323
 324         len = nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*ifi));
 325         attr = (struct nlattr *) ((void *) ifi + NLMSG_ALIGN(sizeof(*ifi)));
 326         if (libbpf_nla_parse(tb, IFLA_MAX, attr, len, NULL) != 0)
 327                 return -LIBBPF_ERRNO__NLPARSE;
 328
 329         return dump_link_nlmsg(cookie, ifi, tb);
 330 }
 331
 332 static int netlink_get_link(int sock, unsigned int nl_pid,
 333                             dump_nlmsg_t dump_link_nlmsg, void *cookie)
 334 {
 335         struct {
 336                 struct nlmsghdr nlh;
 337                 struct ifinfomsg ifm;
 338         } req = {
 339                 .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg)),
 340                 .nlh.nlmsg_type = RTM_GETLINK,
 341                 .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
 342                 .ifm.ifi_family = AF_PACKET,
 343         };
 344         int seq = time(NULL);
 345
 346         req.nlh.nlmsg_seq = seq;
 347         if (send(sock, &req, req.nlh.nlmsg_len, 0) < 0)
 348                 return -errno;
 349
 350         return netlink_recv(sock, nl_pid, seq, __dump_link_nlmsg,
 351                             dump_link_nlmsg, cookie);
 352 }
 353
 354 static int dump_link_nlmsg(void *cookie, void *msg, struct nlattr **tb)
 355 {
 356         struct bpf_netdev_t *netinfo = cookie;
 357         struct ifinfomsg *ifinfo = msg;
 358
 359         if (netinfo->filter_idx > 0 && netinfo->filter_idx != ifinfo->ifi_index)
 360                 return 0;
 361
 362         if (netinfo->used_len == netinfo->array_len) {
 363                 netinfo->devices = realloc(netinfo->devices,
 364                         (netinfo->array_len + 16) *
 365                         sizeof(struct ip_devname_ifindex));
 366                 if (!netinfo->devices)
 367                         return -ENOMEM;
 368
 369                 netinfo->array_len += 16;
 370         }
 371         netinfo->devices[netinfo->used_len].ifindex = ifinfo->ifi_index;
 372         snprintf(netinfo->devices[netinfo->used_len].devname,
 373                  sizeof(netinfo->devices[netinfo->used_len].devname),
 374                  "%s",
 375                  tb[IFLA_IFNAME]
 376                          ? libbpf_nla_getattr_str(tb[IFLA_IFNAME])
 377                          : "");
 378         netinfo->used_len++;
 379
 380         return do_xdp_dump(ifinfo, tb);
 381 }
 382
 383 static int dump_class_qdisc_nlmsg(void *cookie, void *msg, struct nlattr **tb)
 384 {
 385         struct bpf_tcinfo_t *tcinfo = cookie;
 386         struct tcmsg *info = msg;
 387
 388         if (tcinfo->is_qdisc) {
 389                 /* skip clsact qdisc */
 390                 if (tb[TCA_KIND] &&
 391                     strcmp(libbpf_nla_data(tb[TCA_KIND]), "clsact") == 0)
 392                         return 0;
 393                 if (info->tcm_handle == 0)
 394                         return 0;
 395         }
 396
 397         if (tcinfo->used_len == tcinfo->array_len) {
 398                 tcinfo->handle_array = realloc(tcinfo->handle_array,
 399                         (tcinfo->array_len + 16) * sizeof(struct tc_kind_handle));
 400                 if (!tcinfo->handle_array)
 401                         return -ENOMEM;
 402
 403                 tcinfo->array_len += 16;
 404         }
 405         tcinfo->handle_array[tcinfo->used_len].handle = info->tcm_handle;
 406         snprintf(tcinfo->handle_array[tcinfo->used_len].kind,
 407                  sizeof(tcinfo->handle_array[tcinfo->used_len].kind),
 408                  "%s",
 409                  tb[TCA_KIND]
 410                          ? libbpf_nla_getattr_str(tb[TCA_KIND])
 411                          : "unknown");
 412         tcinfo->used_len++;
 413
 414         return 0;
 415 }
 416
 417 static int dump_filter_nlmsg(void *cookie, void *msg, struct nlattr **tb)
 418 {
 419         const struct bpf_filter_t *filter_info = cookie;
 420
 421         return do_filter_dump((struct tcmsg *)msg, tb, filter_info->kind,
 422                               filter_info->devname, filter_info->ifindex);
 423 }
 424
 425 static int show_dev_tc_bpf(int sock, unsigned int nl_pid,
 426                            struct ip_devname_ifindex *dev)
 427 {
 428         struct bpf_filter_t filter_info;
 429         struct bpf_tcinfo_t tcinfo;
 430         int i, handle, ret = 0;
 431
 432         tcinfo.handle_array = NULL;
 433         tcinfo.used_len = 0;
 434         tcinfo.array_len = 0;
 435
 436         tcinfo.is_qdisc = false;
 437         ret = netlink_get_class(sock, nl_pid, dev->ifindex,
 438                                 dump_class_qdisc_nlmsg, &tcinfo);
 439         if (ret)
 440                 goto out;
 441
 442         tcinfo.is_qdisc = true;
 443         ret = netlink_get_qdisc(sock, nl_pid, dev->ifindex,
 444                                 dump_class_qdisc_nlmsg, &tcinfo);
 445         if (ret)
 446                 goto out;
 447
 448         filter_info.devname = dev->devname;
 449         filter_info.ifindex = dev->ifindex;
 450         for (i = 0; i < tcinfo.used_len; i++) {
 451                 filter_info.kind = tcinfo.handle_array[i].kind;
 452                 ret = netlink_get_filter(sock, nl_pid, dev->ifindex,
 453                                          tcinfo.handle_array[i].handle,
 454                                          dump_filter_nlmsg, &filter_info);
 455                 if (ret)
 456                         goto out;
 457         }
 458
 459         /* root, ingress and egress handle */
 460         handle = TC_H_ROOT;
 461         filter_info.kind = "root";
 462         ret = netlink_get_filter(sock, nl_pid, dev->ifindex, handle,
 463                                  dump_filter_nlmsg, &filter_info);
 464         if (ret)
 465                 goto out;
 466
 467         handle = TC_H_MAKE(TC_H_CLSACT, TC_H_MIN_INGRESS);
 468         filter_info.kind = "clsact/ingress";
 469         ret = netlink_get_filter(sock, nl_pid, dev->ifindex, handle,
 470                                  dump_filter_nlmsg, &filter_info);
 471         if (ret)
 472                 goto out;
 473
 474         handle = TC_H_MAKE(TC_H_CLSACT, TC_H_MIN_EGRESS);
 475         filter_info.kind = "clsact/egress";
 476         ret = netlink_get_filter(sock, nl_pid, dev->ifindex, handle,
 477                                  dump_filter_nlmsg, &filter_info);
 478         if (ret)
 479                 goto out;
 480
 481 out:
 482         free(tcinfo.handle_array);
 483         return 0;
 484 }
 485
 486 static int query_flow_dissector(struct bpf_attach_info *attach_info)
 487 {
 488         __u32 attach_flags;
 489         __u32 prog_ids[1];
 490         __u32 prog_cnt;
 491         int err;
 492         int fd;
 493
 494         fd = open("/proc/self/ns/net", O_RDONLY);
 495         if (fd < 0) {
 496                 p_err("can't open /proc/self/ns/net: %s",
 497                       strerror(errno));
 498                 return -1;
 499         }
 500         prog_cnt = ARRAY_SIZE(prog_ids);
 501         err = bpf_prog_query(fd, BPF_FLOW_DISSECTOR, 0,
 502                              &attach_flags, prog_ids, &prog_cnt);
 503         close(fd);
 504         if (err) {
 505                 if (errno == EINVAL) {
 506                         /* Older kernel's don't support querying
 507                          * flow dissector programs.
 508                          */
 509                         errno = 0;
 510                         return 0;
 511                 }
 512                 p_err("can't query prog: %s", strerror(errno));
 513                 return -1;
 514         }
 515
 516         if (prog_cnt == 1)
 517                 attach_info->flow_dissector_id = prog_ids[0];
 518
 519         return 0;
 520 }
 521
 522 static int net_parse_dev(int *argc, char ***argv)
 523 {
 524         int ifindex;
 525
 526         if (is_prefix(**argv, "dev")) {
 527                 NEXT_ARGP();
 528
 529                 ifindex = if_nametoindex(**argv);
 530                 if (!ifindex)
 531                         p_err("invalid devname %s", **argv);
 532
 533                 NEXT_ARGP();
 534         } else {
 535                 p_err("expected 'dev', got: '%s'?", **argv);
 536                 return -1;
 537         }
 538
 539         return ifindex;
 540 }
 541
 542 static int do_attach_detach_xdp(int progfd, enum net_attach_type attach_type,
 543                                 int ifindex, bool overwrite)
 544 {
 545         __u32 flags = 0;
 546
 547         if (!overwrite)
 548                 flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
 549         if (attach_type == NET_ATTACH_TYPE_XDP_GENERIC)
 550                 flags |= XDP_FLAGS_SKB_MODE;
 551         if (attach_type == NET_ATTACH_TYPE_XDP_DRIVER)
 552                 flags |= XDP_FLAGS_DRV_MODE;
 553         if (attach_type == NET_ATTACH_TYPE_XDP_OFFLOAD)
 554                 flags |= XDP_FLAGS_HW_MODE;
 555
 556         return bpf_xdp_attach(ifindex, progfd, flags, NULL);
 557 }
 558
 559 static int do_attach(int argc, char **argv)
 560 {
 561         enum net_attach_type attach_type;
 562         int progfd, ifindex, err = 0;
 563         bool overwrite = false;
 564
 565         /* parse attach args */
 566         if (!REQ_ARGS(5))
 567                 return -EINVAL;
 568
 569         attach_type = parse_attach_type(*argv);
 570         if (attach_type == net_attach_type_size) {
 571                 p_err("invalid net attach/detach type: %s", *argv);
 572                 return -EINVAL;
 573         }
 574         NEXT_ARG();
 575
 576         progfd = prog_parse_fd(&argc, &argv);
 577         if (progfd < 0)
 578                 return -EINVAL;
 579
 580         ifindex = net_parse_dev(&argc, &argv);
 581         if (ifindex < 1) {
 582                 err = -EINVAL;
 583                 goto cleanup;
 584         }
 585
 586         if (argc) {
 587                 if (is_prefix(*argv, "overwrite")) {
 588                         overwrite = true;
 589                 } else {
 590                         p_err("expected 'overwrite', got: '%s'?", *argv);
 591                         err = -EINVAL;
 592                         goto cleanup;
 593                 }
 594         }
 595
 596         /* attach xdp prog */
 597         if (is_prefix("xdp", attach_type_strings[attach_type]))
 598                 err = do_attach_detach_xdp(progfd, attach_type, ifindex,
 599                                            overwrite);
 600         if (err) {
 601                 p_err("interface %s attach failed: %s",
 602                       attach_type_strings[attach_type], strerror(-err));
 603                 goto cleanup;
 604         }
 605
 606         if (json_output)
 607                 jsonw_null(json_wtr);
 608 cleanup:
 609         close(progfd);
 610         return err;
 611 }
 612
 613 static int do_detach(int argc, char **argv)
 614 {
 615         enum net_attach_type attach_type;
 616         int progfd, ifindex, err = 0;
 617
 618         /* parse detach args */
 619         if (!REQ_ARGS(3))
 620                 return -EINVAL;
 621
 622         attach_type = parse_attach_type(*argv);
 623         if (attach_type == net_attach_type_size) {
 624                 p_err("invalid net attach/detach type: %s", *argv);
 625                 return -EINVAL;
 626         }
 627         NEXT_ARG();
 628
 629         ifindex = net_parse_dev(&argc, &argv);
 630         if (ifindex < 1)
 631                 return -EINVAL;
 632
 633         /* detach xdp prog */
 634         progfd = -1;
 635         if (is_prefix("xdp", attach_type_strings[attach_type]))
 636                 err = do_attach_detach_xdp(progfd, attach_type, ifindex, NULL);
 637
 638         if (err < 0) {
 639                 p_err("interface %s detach failed: %s",
 640                       attach_type_strings[attach_type], strerror(-err));
 641                 return err;
 642         }
 643
 644         if (json_output)
 645                 jsonw_null(json_wtr);
 646
 647         return 0;
 648 }
 649
 650 static int netfilter_link_compar(const void *a, const void *b)
 651 {
 652         const struct bpf_link_info *nfa = a;
 653         const struct bpf_link_info *nfb = b;
 654         int delta;
 655
 656         delta = nfa->netfilter.pf - nfb->netfilter.pf;
 657         if (delta)
 658                 return delta;
 659
 660         delta = nfa->netfilter.hooknum - nfb->netfilter.hooknum;
 661         if (delta)
 662                 return delta;
 663
 664         if (nfa->netfilter.priority < nfb->netfilter.priority)
 665                 return -1;
 666         if (nfa->netfilter.priority > nfb->netfilter.priority)
 667                 return 1;
 668
 669         return nfa->netfilter.flags - nfb->netfilter.flags;
 670 }
 671
 672 static void show_link_netfilter(void)
 673 {
 674         unsigned int nf_link_len = 0, nf_link_count = 0;
 675         struct bpf_link_info *nf_link_info = NULL;
 676         __u32 id = 0;
 677
 678         while (true) {
 679                 struct bpf_link_info info;
 680                 int fd, err;
 681                 __u32 len;
 682
 683                 err = bpf_link_get_next_id(id, &id);
 684                 if (err) {
 685                         if (errno == ENOENT)
 686                                 break;
 687                         p_err("can't get next link: %s (id %d)", strerror(errno), id);
 688                         break;
 689                 }
 690
 691                 fd = bpf_link_get_fd_by_id(id);
 692                 if (fd < 0) {
 693                         p_err("can't get link by id (%u): %s", id, strerror(errno));
 694                         continue;
 695                 }
 696
 697                 memset(&info, 0, sizeof(info));
 698                 len = sizeof(info);
 699
 700                 err = bpf_link_get_info_by_fd(fd, &info, &len);
 701
 702                 close(fd);
 703
 704                 if (err) {
 705                         p_err("can't get link info for fd %d: %s", fd, strerror(errno));
 706                         continue;
 707                 }
 708
 709                 if (info.type != BPF_LINK_TYPE_NETFILTER)
 710                         continue;
 711
 712                 if (nf_link_count >= nf_link_len) {
 713                         static const unsigned int max_link_count = INT_MAX / sizeof(info);
 714                         struct bpf_link_info *expand;
 715
 716                         if (nf_link_count > max_link_count) {
 717                                 p_err("cannot handle more than %u links\n", max_link_count);
 718                                 break;
 719                         }
 720
 721                         nf_link_len += 16;
 722
 723                         expand = realloc(nf_link_info, nf_link_len * sizeof(info));
 724                         if (!expand) {
 725                                 p_err("realloc: %s",  strerror(errno));
 726                                 break;
 727                         }
 728
 729                         nf_link_info = expand;
 730                 }
 731
 732                 nf_link_info[nf_link_count] = info;
 733                 nf_link_count++;
 734         }
 735
 736         qsort(nf_link_info, nf_link_count, sizeof(*nf_link_info), netfilter_link_compar);
 737
 738         for (id = 0; id < nf_link_count; id++) {
 739                 NET_START_OBJECT;
 740                 if (json_output)
 741                         netfilter_dump_json(&nf_link_info[id], json_wtr);
 742                 else
 743                         netfilter_dump_plain(&nf_link_info[id]);
 744
 745                 NET_DUMP_UINT("id", " prog_id %u", nf_link_info[id].prog_id);
 746                 NET_END_OBJECT;
 747         }
 748
 749         free(nf_link_info);
 750 }
 751
 752 static int do_show(int argc, char **argv)
 753 {
 754         struct bpf_attach_info attach_info = {};
 755         int i, sock, ret, filter_idx = -1;
 756         struct bpf_netdev_t dev_array;
 757         unsigned int nl_pid = 0;
 758         char err_buf[256];
 759
 760         if (argc == 2) {
 761                 filter_idx = net_parse_dev(&argc, &argv);
 762                 if (filter_idx < 1)
 763                         return -1;
 764         } else if (argc != 0) {
 765                 usage();
 766         }
 767
 768         ret = query_flow_dissector(&attach_info);
 769         if (ret)
 770                 return -1;
 771
 772         sock = netlink_open(&nl_pid);
 773         if (sock < 0) {
 774                 fprintf(stderr, "failed to open netlink sock\n");
 775                 return -1;
 776         }
 777
 778         dev_array.devices = NULL;
 779         dev_array.used_len = 0;
 780         dev_array.array_len = 0;
 781         dev_array.filter_idx = filter_idx;
 782
 783         if (json_output)
 784                 jsonw_start_array(json_wtr);
 785         NET_START_OBJECT;
 786         NET_START_ARRAY("xdp", "%s:\n");
 787         ret = netlink_get_link(sock, nl_pid, dump_link_nlmsg, &dev_array);
 788         NET_END_ARRAY("\n");
 789
 790         if (!ret) {
 791                 NET_START_ARRAY("tc", "%s:\n");
 792                 for (i = 0; i < dev_array.used_len; i++) {
 793                         ret = show_dev_tc_bpf(sock, nl_pid,
 794                                               &dev_array.devices[i]);
 795                         if (ret)
 796                                 break;
 797                 }
 798                 NET_END_ARRAY("\n");
 799         }
 800
 801         NET_START_ARRAY("flow_dissector", "%s:\n");
 802         if (attach_info.flow_dissector_id > 0)
 803                 NET_DUMP_UINT("id", "id %u", attach_info.flow_dissector_id);
 804         NET_END_ARRAY("\n");
 805
 806         NET_START_ARRAY("netfilter", "%s:\n");
 807         show_link_netfilter();
 808         NET_END_ARRAY("\n");
 809
 810         NET_END_OBJECT;
 811         if (json_output)
 812                 jsonw_end_array(json_wtr);
 813
 814         if (ret) {
 815                 if (json_output)
 816                         jsonw_null(json_wtr);
 817                 libbpf_strerror(ret, err_buf, sizeof(err_buf));
 818                 fprintf(stderr, "Error: %s\n", err_buf);
 819         }
 820         free(dev_array.devices);
 821         close(sock);
 822         return ret;
 823 }
 824
 825 static int do_help(int argc, char **argv)
 826 {
 827         if (json_output) {
 828                 jsonw_null(json_wtr);
 829                 return 0;
 830         }
 831
 832         fprintf(stderr,
 833                 "Usage: %1$s %2$s { show | list } [dev <devname>]\n"
 834                 "       %1$s %2$s attach ATTACH_TYPE PROG dev <devname> [ overwrite ]\n"
 835                 "       %1$s %2$s detach ATTACH_TYPE dev <devname>\n"
 836                 "       %1$s %2$s help\n"
 837                 "\n"
 838                 "       " HELP_SPEC_PROGRAM "\n"
 839                 "       ATTACH_TYPE := { xdp | xdpgeneric | xdpdrv | xdpoffload }\n"
 840                 "       " HELP_SPEC_OPTIONS " }\n"
 841                 "\n"
 842                 "Note: Only xdp and tc attachments are supported now.\n"
 843                 "      For progs attached to cgroups, use \"bpftool cgroup\"\n"
 844                 "      to dump program attachments. For program types\n"
 845                 "      sk_{filter,skb,msg,reuseport} and lwt/seg6, please\n"
 846                 "      consult iproute2.\n"
 847                 "",
 848                 bin_name, argv[-2]);
 849
 850         return 0;
 851 }
 852
 853 static const struct cmd cmds[] = {
 854         { "show",       do_show },
 855         { "list",       do_show },
 856         { "attach",     do_attach },
 857         { "detach",     do_detach },
 858         { "help",       do_help },
 859         { 0 }
 860 };
 861
 862 int do_net(int argc, char **argv)
 863 {
 864         return cmd_select(cmds, argc, argv, do_help);
 865 }