samples/bpf/tc_l2_redirect_user.c

   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 "libbpf.h"
  17
  18 static 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
  26 int 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
  69 out:
  70         if (array_fd != -1)
  71                 close(array_fd);
  72         return ret;
  73 }