LXR linux/samples/bpf/test_cgrp2

   1// SPDX-License-Identifier: GPL-2.0
   2/* eBPF example program:
   3 *
   4 * - Loads eBPF program
   5 *
   6 *   The eBPF program loads a filter from file and attaches the
   7 *   program to a cgroup using BPF_PROG_ATTACH
   8 */
   9
  10#define _GNU_SOURCE
  11
  12#include <stdio.h>
  13#include <stdlib.h>
  14#include <stddef.h>
  15#include <string.h>
  16#include <unistd.h>
  17#include <assert.h>
  18#include <errno.h>
  19#include <fcntl.h>
  20#include <net/if.h>
  21#include <linux/bpf.h>
  22#include <bpf/bpf.h>
  23#include <bpf/libbpf.h>
  24
  25#include "bpf_insn.h"
  26
  27static int usage(const char *argv0)
  28{
  29        printf("Usage: %s cg-path filter-path [filter-id]\n", argv0);
  30        return EXIT_FAILURE;
  31}
  32
  33int main(int argc, char **argv)
  34{
  35        int cg_fd, err, ret = EXIT_FAILURE, filter_id = 0, prog_cnt = 0;
  36        const char *link_pin_path = "/sys/fs/bpf/test_cgrp2_sock2";
  37        struct bpf_link *link = NULL;
  38        struct bpf_program *progs[2];
  39        struct bpf_program *prog;
  40        struct bpf_object *obj;
  41
  42        if (argc < 3)
  43                return usage(argv[0]);
  44
  45        if (argc > 3)
  46                filter_id = atoi(argv[3]);
  47
  48        cg_fd = open(argv[1], O_DIRECTORY | O_RDONLY);
  49        if (cg_fd < 0) {
  50                printf("Failed to open cgroup path: '%s'\n", strerror(errno));
  51                return ret;
  52        }
  53
  54        obj = bpf_object__open_file(argv[2], NULL);
  55        if (libbpf_get_error(obj)) {
  56                printf("ERROR: opening BPF object file failed\n");
  57                return ret;
  58        }
  59
  60        bpf_object__for_each_program(prog, obj) {
  61                progs[prog_cnt] = prog;
  62                prog_cnt++;
  63        }
  64
  65        if (filter_id >= prog_cnt) {
  66                printf("Invalid program id; program not found in file\n");
  67                goto cleanup;
  68        }
  69
  70        /* load BPF program */
  71        if (bpf_object__load(obj)) {
  72                printf("ERROR: loading BPF object file failed\n");
  73                goto cleanup;
  74        }
  75
  76        link = bpf_program__attach_cgroup(progs[filter_id], cg_fd);
  77        if (libbpf_get_error(link)) {
  78                printf("ERROR: bpf_program__attach failed\n");
  79                link = NULL;
  80                goto cleanup;
  81        }
  82
  83        err = bpf_link__pin(link, link_pin_path);
  84        if (err < 0) {
  85                printf("ERROR: bpf_link__pin failed: %d\n", err);
  86                goto cleanup;
  87        }
  88
  89        ret = EXIT_SUCCESS;
  90
  91cleanup:
  92        bpf_link__destroy(link);
  93        bpf_object__close(obj);
  94        return ret;
  95}
  96