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 * $FreeBSD$
28 */
29
30#include <err.h>
31#include <errno.h>
32#include <net/if.h>
33#include <sys/ioctl.h>
34#include <stdio.h>
35#include <stdlib.h>
36#include <string.h>
37#include <libifconfig.h>
38
39
40int
41main(int argc, char *argv[])
42{
43	char *ifname, *ptr;
44	int mtu;
45	ifconfig_handle_t *lifh;
46
47	if (argc != 3) {
48		errx(EINVAL, "Invalid number of arguments."
49		    " First argument should be interface name, second argument"
50		    " should be the MTU to set.");
51	}
52
53	/* We have a static number of arguments. Therefore we can do it simple. */
54	ifname = strdup(argv[1]);
55	mtu = (int)strtol(argv[2], &ptr, 10);
56
57	printf("Interface name: %s\n", ifname);
58	printf("New MTU: %d", mtu);
59
60	lifh = ifconfig_open();
61	if (lifh == NULL) {
62		errx(ENOMEM, "Failed to open libifconfig handle.");
63		return (-1);
64	}
65
66	if (ifconfig_set_mtu(lifh, ifname, mtu) == 0) {
67		printf("Successfully changed MTU of %s to %d\n", ifname, mtu);
68		ifconfig_close(lifh);
69		lifh = NULL;
70		free(ifname);
71		return (0);
72	}
73
74	switch (ifconfig_err_errtype(lifh)) {
75	case SOCKET:
76		warnx("couldn't create socket. This shouldn't happen.\n");
77		break;
78	case IOCTL:
79		if (ifconfig_err_ioctlreq(lifh) == SIOCSIFMTU) {
80			warnx("Failed to set MTU (SIOCSIFMTU)\n");
81		} else {
82			warnx(
83				"Failed to set MTU due to error in unexpected ioctl() call %lu. Error code: %i.\n",
84				ifconfig_err_ioctlreq(lifh),
85				ifconfig_err_errno(lifh));
86		}
87		break;
88	default:
89		warnx(
90			"Should basically never end up here in this example.\n");
91		break;
92	}
93
94	ifconfig_close(lifh);
95	lifh = NULL;
96	free(ifname);
97	return (-1);
98}
99