libnl  3.5.0
nl-link-name2ifindex.c
1 /* SPDX-License-Identifier: LGPL-2.1-only */
2 /*
3  * src/nl-link-name2ifindex.c Transform a interface name to its index
4  *
5  * This library is free software; you can redistribute it and/or
6  * modify it under the terms of the GNU Lesser General Public
7  * License as published by the Free Software Foundation version 2.1
8  * of the License.
9  *
10  * Copyright (c) 2003-2008 Thomas Graf <tgraf@suug.ch>
11  */
12 
13 #include <netlink/cli/utils.h>
14 #include <netlink/cli/link.h>
15 
16 #include <linux/netlink.h>
17 
18 static void print_usage(void)
19 {
20  printf("Usage: nl-link-name2ifindex <name>\n");
21  exit(0);
22 }
23 
24 int main(int argc, char *argv[])
25 {
26  struct nl_sock *sock;
27  struct nl_cache *link_cache;
28  uint32_t ifindex;
29 
30  if (argc < 2)
31  print_usage();
32 
33  sock = nl_cli_alloc_socket();
34  nl_cli_connect(sock, NETLINK_ROUTE);
35  link_cache = nl_cli_link_alloc_cache(sock);
36 
37  if (!(ifindex = rtnl_link_name2i(link_cache, argv[1])))
38  nl_cli_fatal(ENOENT, "Interface \"%s\" does not exist",
39  argv[1]);
40 
41  printf("%u\n", ifindex);
42 
43  return 0;
44 }
void nl_cli_fatal(int err, const char *fmt,...)
Print error message and quit application.
Definition: utils.c:78