tools/bpf/bpftool/net.c

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