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 #include <bpf/bpf.h>
  23
  24 #include "bpf_insn.h"
  25 #include "bpf_load.h"
  26
  27 static int usage(const char *argv0)
  28 {
  29         printf("Usage: %s cg-path filter-path [filter-id]\n", argv0);
  30         return EXIT_FAILURE;
  31 }
  32
  33 int main(int argc, char **argv)
  34 {
  35         int cg_fd, ret, filter_id = 0;
  36
  37         if (argc < 3)
  38                 return usage(argv[0]);
  39
  40         cg_fd = open(argv[1], O_DIRECTORY | O_RDONLY);
  41         if (cg_fd < 0) {
  42                 printf("Failed to open cgroup path: '%s'\n", strerror(errno));
  43                 return EXIT_FAILURE;
  44         }
  45
  46         if (load_bpf_file(argv[2]))
  47                 return EXIT_FAILURE;
  48
  49         printf("Output from kernel verifier:\n%s\n-------\n", bpf_log_buf);
  50
  51         if (argc > 3)
  52                 filter_id = atoi(argv[3]);
  53
  54         if (filter_id >= prog_cnt) {
  55                 printf("Invalid program id; program not found in file\n");
  56                 return EXIT_FAILURE;
  57         }
  58
  59         ret = bpf_prog_attach(prog_fd[filter_id], cg_fd,
  60                               BPF_CGROUP_INET_SOCK_CREATE, 0);
  61         if (ret < 0) {
  62                 printf("Failed to attach prog to cgroup: '%s'\n",
  63                        strerror(errno));
  64                 return EXIT_FAILURE;
  65         }
  66
  67         return EXIT_SUCCESS;
  68 }