samples/bpf/test_cgrp2_sock2.c

   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
  23 #include "libbpf.h"
  24 #include "bpf_load.h"
  25
  26 static int usage(const char *argv0)
  27 {
  28         printf("Usage: %s cg-path filter-path [filter-id]\n", argv0);
  29         return EXIT_FAILURE;
  30 }
  31
  32 int main(int argc, char **argv)
  33 {
  34         int cg_fd, ret, filter_id = 0;
  35
  36         if (argc < 3)
  37                 return usage(argv[0]);
  38
  39         cg_fd = open(argv[1], O_DIRECTORY | O_RDONLY);
  40         if (cg_fd < 0) {
  41                 printf("Failed to open cgroup path: '%s'\n", strerror(errno));
  42                 return EXIT_FAILURE;
  43         }
  44
  45         if (load_bpf_file(argv[2]))
  46                 return EXIT_FAILURE;
  47
  48         printf("Output from kernel verifier:\n%s\n-------\n", bpf_log_buf);
  49
  50         if (argc > 3)
  51                 filter_id = atoi(argv[3]);
  52
  53         if (filter_id > prog_cnt) {
  54                 printf("Invalid program id; program not found in file\n");
  55                 return EXIT_FAILURE;
  56         }
  57
  58         ret = bpf_prog_attach(prog_fd[filter_id], cg_fd,
  59                               BPF_CGROUP_INET_SOCK_CREATE, 0);
  60         if (ret < 0) {
  61                 printf("Failed to attach prog to cgroup: '%s'\n",
  62                        strerror(errno));
  63                 return EXIT_FAILURE;
  64         }
  65
  66         return EXIT_SUCCESS;
  67 }