libnl  3.2.24-rc1
nl-link-name2ifindex.c
1 /*
2  * src/nl-link-name2ifindex.c Transform a interface name to its index
3  *
4  * This library is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU Lesser General Public
6  * License as published by the Free Software Foundation version 2.1
7  * of the License.
8  *
9  * Copyright (c) 2003-2008 Thomas Graf <tgraf@suug.ch>
10  */
11 
12 #include <netlink/cli/utils.h>
13 #include <netlink/cli/link.h>
14 
15 static void print_usage(void)
16 {
17  printf("Usage: nl-link-name2ifindex <name>\n");
18  exit(0);
19 }
20 
21 int main(int argc, char *argv[])
22 {
23  struct nl_sock *sock;
24  struct nl_cache *link_cache;
25  uint32_t ifindex;
26 
27  if (argc < 2)
28  print_usage();
29 
30  sock = nl_cli_alloc_socket();
31  nl_cli_connect(sock, NETLINK_ROUTE);
32  link_cache = nl_cli_link_alloc_cache(sock);
33 
34  if (!(ifindex = rtnl_link_name2i(link_cache, argv[1])))
35  nl_cli_fatal(ENOENT, "Interface \"%s\" does not exist",
36  argv[1]);
37 
38  printf("%u\n", ifindex);
39 
40  return 0;
41 }