samples/bpf/tc_l2_redirect_user.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /* Copyright (c) 2016 Facebook
   3  */
   4 #include <linux/unistd.h>
   5 #include <linux/bpf.h>
   6
   7 #include <stdlib.h>
   8 #include <stdio.h>
   9 #include <unistd.h>
  10 #include <string.h>
  11 #include <errno.h>
  12
  13 #include <bpf/bpf.h>
  14
  15 static void usage(void)
  16 {
  17         printf("Usage: tc_l2_ipip_redirect [...]\n");
  18         printf("       -U <file>   Update an already pinned BPF array\n");
  19         printf("       -i <ifindex> Interface index\n");
  20         printf("       -h          Display this help\n");
  21 }
  22
  23 int main(int argc, char **argv)
  24 {
  25         const char *pinned_file = NULL;
  26         int ifindex = -1;
  27         int array_key = 0;
  28         int array_fd = -1;
  29         int ret = -1;
  30         int opt;
  31
  32         while ((opt = getopt(argc, argv, "F:U:i:")) != -1) {
  33                 switch (opt) {
  34                 /* General args */
  35                 case 'U':
  36                         pinned_file = optarg;
  37                         break;
  38                 case 'i':
  39                         ifindex = atoi(optarg);
  40                         break;
  41                 default:
  42                         usage();
  43                         goto out;
  44                 }
  45         }
  46
  47         if (ifindex < 0 || !pinned_file) {
  48                 usage();
  49                 goto out;
  50         }
  51
  52         array_fd = bpf_obj_get(pinned_file);
  53         if (array_fd < 0) {
  54                 fprintf(stderr, "bpf_obj_get(%s): %s(%d)\n",
  55                         pinned_file, strerror(errno), errno);
  56                 goto out;
  57         }
  58
  59         /* bpf_tunnel_key.remote_ipv4 expects host byte orders */
  60         ret = bpf_map_update_elem(array_fd, &array_key, &ifindex, 0);
  61         if (ret) {
  62                 perror("bpf_map_update_elem");
  63                 goto out;
  64         }
  65
  66 out:
  67         if (array_fd != -1)
  68                 close(array_fd);
  69         return ret;
  70 }