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