samples/bpf/test_cgrp2_sock2.c

   1 /* eBPF example program:
   2  *
   3  * - Loads eBPF program
   4  *
   5  *   The eBPF program loads a filter from file and attaches the
   6  *   program to a cgroup using BPF_PROG_ATTACH
   7  */
   8
   9 #define _GNU_SOURCE
  10
  11 #include <stdio.h>
  12 #include <stdlib.h>
  13 #include <stddef.h>
  14 #include <string.h>
  15 #include <unistd.h>
  16 #include <assert.h>
  17 #include <errno.h>
  18 #include <fcntl.h>
  19 #include <net/if.h>
  20 #include <linux/bpf.h>
  21
  22 #include "libbpf.h"
  23 #include "bpf_load.h"
  24
  25 static int usage(const char *argv0)
  26 {
  27         printf("Usage: %s cg-path filter-path [filter-id]\n", argv0);
  28         return EXIT_FAILURE;
  29 }
  30
  31 int main(int argc, char **argv)
  32 {
  33         int cg_fd, ret, filter_id = 0;
  34
  35         if (argc < 3)
  36                 return usage(argv[0]);
  37
  38         cg_fd = open(argv[1], O_DIRECTORY | O_RDONLY);
  39         if (cg_fd < 0) {
  40                 printf("Failed to open cgroup path: '%s'\n", strerror(errno));
  41                 return EXIT_FAILURE;
  42         }
  43
  44         if (load_bpf_file(argv[2]))
  45                 return EXIT_FAILURE;
  46
  47         printf("Output from kernel verifier:\n%s\n-------\n", bpf_log_buf);
  48
  49         if (argc > 3)
  50                 filter_id = atoi(argv[3]);
  51
  52         if (filter_id > prog_cnt) {
  53                 printf("Invalid program id; program not found in file\n");
  54                 return EXIT_FAILURE;
  55         }
  56
  57         ret = bpf_prog_attach(prog_fd[filter_id], cg_fd,
  58                               BPF_CGROUP_INET_SOCK_CREATE, 0);
  59         if (ret < 0) {
  60                 printf("Failed to attach prog to cgroup: '%s'\n",
  61                        strerror(errno));
  62                 return EXIT_FAILURE;
  63         }
  64
  65         return EXIT_SUCCESS;
  66 }