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/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
  30struct ip_devname_ifindex {
  31        char    devname[64];
  32        int     ifindex;
  33};
  34
  35struct bpf_netdev_t {
  36        struct ip_devname_ifindex *devices;
  37        int     used_len;
  38        int     array_len;
  39        int     filter_idx;
  40};
  41
  42struct tc_kind_handle {
  43        char    kind[64];
  44        int     handle;
  45};
  46
  47struct bpf_tcinfo_t {
  48        struct tc_kind_handle   *handle_array;
  49        int                     used_len;
  50        int                     array_len;
  51        bool                    is_qdisc;
  52};
  53
  54struct bpf_filter_t {
  55        const char      *kind;
  56        const char      *devname;
  57        int             ifindex;
  58};
  59
  60struct bpf_attach_info {
  61        __u32 flow_dissector_id;
  62};
  63
  64enum 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
  71static 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
  78const size_t net_attach_type_size = ARRAY_SIZE(attach_type_strings);
  79
  80static 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
  93typedef int (*dump_nlmsg_t)(void *cookie, void *msg, struct nlattr **tb);
  94
  95typedef int (*__dump_nlmsg_t)(struct nlmsghdr *nlmsg, dump_nlmsg_t, void *cookie);
  96
  97static 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
 135cleanup:
 136        close(sock);
 137        return ret;
 138}
 139
 140static 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;
 194done:
 195        return ret;
 196}
 197
 198static 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
 214static 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
 237static 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
 253static 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
 276static 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
 292static 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
 316static 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
 331static 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
 353static 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
 382static 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
 416static 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
 424static 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
 480out:
 481        free(tcinfo.handle_array);
 482        return 0;
 483}
 484
 485static 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
 521static 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
 541static 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
 558static 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                err = -EINVAL;
 582                goto cleanup;
 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                        err = -EINVAL;
 591                        goto cleanup;
 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        if (err) {
 600                p_err("interface %s attach failed: %s",
 601                      attach_type_strings[attach_type], strerror(-err));
 602                goto cleanup;
 603        }
 604
 605        if (json_output)
 606                jsonw_null(json_wtr);
 607cleanup:
 608        close(progfd);
 609        return err;
 610}
 611
 612static 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
 649static 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
 718static 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
 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