1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2025 Gleb Smirnoff <glebius@FreeBSD.org>
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28 #include <sys/socket.h>
29 #include <netinet/in.h>
30 #include <arpa/inet.h>
31 #include <assert.h>
32 #include <err.h>
33
34 int
main(int argc,char * argv[])35 main(int argc, char *argv[])
36 {
37 struct sockaddr_in sin = {
38 .sin_family = AF_INET,
39 .sin_len = sizeof(struct sockaddr_in),
40 };
41 struct in_addr in;
42 int s, rv;
43
44 if (argc < 2)
45 errx(1, "Usage: %s IPv4-address", argv[0]);
46
47 if (inet_pton(AF_INET, argv[1], &in) != 1)
48 err(1, "inet_pton(%s) failed", argv[1]);
49
50 assert((s = socket(PF_INET, SOCK_DGRAM, 0)) > 0);
51 assert(bind(s, (struct sockaddr *)&sin, sizeof(sin)) == 0);
52 assert(setsockopt(s, IPPROTO_IP, IP_MULTICAST_IF, &in, sizeof(in))
53 == 0);
54 /* RFC 6676 */
55 assert(inet_pton(AF_INET, "233.252.0.1", &sin.sin_addr) == 1);
56 sin.sin_port = htons(6676);
57 rv = sendto(s, &sin, sizeof(sin), 0,
58 (struct sockaddr *)&sin, sizeof(sin));
59 if (rv != sizeof(sin))
60 err(1, "sendto failed");
61
62 return (0);
63 }
64