LXR linux/samples/bpf/tc_l2_redirect

   1/* Copyright (c) 2016 Facebook
   2 *
   3 * This program is free software; you can redistribute it and/or
   4 * modify it under the terms of version 2 of the GNU General Public
   5 * License as published by the Free Software Foundation.
   6 */
   7#include <linux/unistd.h>
   8#include <linux/bpf.h>
   9
  10#include <stdlib.h>
  11#include <stdio.h>
  12#include <unistd.h>
  13#include <string.h>
  14#include <errno.h>
  15
  16#include <bpf/bpf.h>
  17
  18static void usage(void)
  19{
  20        printf("Usage: tc_l2_ipip_redirect [...]\n");
  21        printf("       -U <file>   Update an already pinned BPF array\n");
  22        printf("       -i <ifindex> Interface index\n");
  23        printf("       -h          Display this help\n");
  24}
  25
  26int main(int argc, char **argv)
  27{
  28        const char *pinned_file = NULL;
  29        int ifindex = -1;
  30        int array_key = 0;
  31        int array_fd = -1;
  32        int ret = -1;
  33        int opt;
  34
  35        while ((opt = getopt(argc, argv, "F:U:i:")) != -1) {
  36                switch (opt) {
  37                /* General args */
  38                case 'U':
  39                        pinned_file = optarg;
  40                        break;
  41                case 'i':
  42                        ifindex = atoi(optarg);
  43                        break;
  44                default:
  45                        usage();
  46                        goto out;
  47                }
  48        }
  49
  50        if (ifindex < 0 || !pinned_file) {
  51                usage();
  52                goto out;
  53        }
  54
  55        array_fd = bpf_obj_get(pinned_file);
  56        if (array_fd < 0) {
  57                fprintf(stderr, "bpf_obj_get(%s): %s(%d)\n",
  58                        pinned_file, strerror(errno), errno);
  59                goto out;
  60        }
  61
  62        /* bpf_tunnel_key.remote_ipv4 expects host byte orders */
  63        ret = bpf_map_update_elem(array_fd, &array_key, &ifindex, 0);
  64        if (ret) {
  65                perror("bpf_map_update_elem");
  66                goto out;
  67        }
  68
  69out:
  70        if (array_fd != -1)
  71                close(array_fd);
  72        return ret;
  73}
  74