1 /*
2 * Copyright (c) 2016-2017, Marie Helene Kvello-Aune
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without modification,
6 * are permitted provided that the following conditions are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright notice,
9 * thislist of conditions and the following disclaimer.
10 *
11 * 2. Redistributions in binary form must reproduce the above copyright notice,
12 * this list of conditions and the following disclaimer in the documentation and/or
13 * other materials provided with the distribution.
14 *
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
18 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
22 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
23 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
25 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28 #include <err.h>
29 #include <errno.h>
30 #include <net/if.h>
31 #include <sys/ioctl.h>
32 #include <stdio.h>
33 #include <stdlib.h>
34 #include <string.h>
35 #include <libifconfig.h>
36
37
38 int
main(int argc,char * argv[])39 main(int argc, char *argv[])
40 {
41 char *ifname, *ptr;
42 int mtu;
43 ifconfig_handle_t *lifh;
44
45 if (argc != 3) {
46 errx(EINVAL, "Invalid number of arguments."
47 " First argument should be interface name, second argument"
48 " should be the MTU to set.");
49 }
50
51 /* We have a static number of arguments. Therefore we can do it simple. */
52 ifname = strdup(argv[1]);
53 mtu = (int)strtol(argv[2], &ptr, 10);
54
55 printf("Interface name: %s\n", ifname);
56 printf("New MTU: %d", mtu);
57
58 lifh = ifconfig_open();
59 if (lifh == NULL) {
60 errx(ENOMEM, "Failed to open libifconfig handle.");
61 return (-1);
62 }
63
64 if (ifconfig_set_mtu(lifh, ifname, mtu) == 0) {
65 printf("Successfully changed MTU of %s to %d\n", ifname, mtu);
66 ifconfig_close(lifh);
67 lifh = NULL;
68 free(ifname);
69 return (0);
70 }
71
72 switch (ifconfig_err_errtype(lifh)) {
73 case SOCKET:
74 warnx("couldn't create socket. This shouldn't happen.\n");
75 break;
76 case IOCTL:
77 if (ifconfig_err_ioctlreq(lifh) == SIOCSIFMTU) {
78 warnx("Failed to set MTU (SIOCSIFMTU)\n");
79 } else {
80 warnx(
81 "Failed to set MTU due to error in unexpected ioctl() call %lu. Error code: %i.\n",
82 ifconfig_err_ioctlreq(lifh),
83 ifconfig_err_errno(lifh));
84 }
85 break;
86 default:
87 warnx(
88 "Should basically never end up here in this example.\n");
89 break;
90 }
91
92 ifconfig_close(lifh);
93 lifh = NULL;
94 free(ifname);
95 return (-1);
96 }
97