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/*-
* SPDX-License-Identifier: BSD-2-Clause
*
* Copyright (c) 2025 Gleb Smirnoff <glebius@FreeBSD.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <assert.h>
#include <err.h>
int
main(int argc, char *argv[])
{
struct sockaddr_in sin = {
.sin_family = AF_INET,
.sin_len = sizeof(struct sockaddr_in),
};
struct in_addr in;
int s, rv;
if (argc < 2)
errx(1, "Usage: %s IPv4-address", argv[0]);
if (inet_pton(AF_INET, argv[1], &in) != 1)
err(1, "inet_pton(%s) failed", argv[1]);
assert((s = socket(PF_INET, SOCK_DGRAM, 0)) > 0);
assert(bind(s, (struct sockaddr *)&sin, sizeof(sin)) == 0);
assert(setsockopt(s, IPPROTO_IP, IP_MULTICAST_IF, &in, sizeof(in))
== 0);
/* RFC 6676 */
assert(inet_pton(AF_INET, "233.252.0.1", &sin.sin_addr) == 1);
sin.sin_port = htons(6676);
rv = sendto(s, &sin, sizeof(sin), 0,
(struct sockaddr *)&sin, sizeof(sin));
if (rv != sizeof(sin))
err(1, "sendto failed");
return (0);
}
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