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 <net/if.h> 32 #include <assert.h> 33 #include <errno.h> 34 #include <limits.h> 35 #include <stdbool.h> 36 #include <stdlib.h> 37 #include <string.h> 38 #include <err.h> 39 40 static in_port_t 41 atop(const char *c) 42 { 43 unsigned long ul; 44 45 errno = 0; 46 if ((ul = strtol(c, NULL, 10)) < 1 || ul > IPPORT_MAX || errno != 0) 47 err(1, "can't parse %s", c); 48 49 return ((in_port_t)ul); 50 } 51 52 int 53 main(int argc, char *argv[]) 54 { 55 struct sockaddr_in src = { 56 .sin_family = AF_INET, 57 .sin_len = sizeof(struct sockaddr_in), 58 }, dst = { 59 .sin_family = AF_INET, 60 .sin_len = sizeof(struct sockaddr_in), 61 }; 62 struct ip_mreqn mreqn; 63 struct in_addr in; 64 int s; 65 bool index; 66 67 if (argc < 7) 68 errx(1, "Usage: %s src-IPv4 src-port dst-IPv4 dst-port " 69 "interface payload", argv[0]); 70 71 if (inet_pton(AF_INET, argv[1], &src.sin_addr) != 1) 72 err(1, "inet_pton(%s) failed", argv[1]); 73 src.sin_port = htons(atop(argv[2])); 74 if (inet_pton(AF_INET, argv[3], &dst.sin_addr) != 1) 75 err(1, "inet_pton(%s) failed", argv[3]); 76 dst.sin_port = htons(atop(argv[4])); 77 if (inet_pton(AF_INET, argv[5], &in) == 1) 78 index = false; 79 else if ((mreqn.imr_ifindex = if_nametoindex(argv[5])) > 0) 80 index = true; 81 else 82 err(1, "if_nametoindex(%s) failed", argv[5]); 83 84 assert((s = socket(PF_INET, SOCK_DGRAM, 0)) > 0); 85 assert(bind(s, (struct sockaddr *)&src, sizeof(src)) == 0); 86 if (index) 87 assert(setsockopt(s, IPPROTO_IP, IP_MULTICAST_IF, &mreqn, 88 sizeof(mreqn)) == 0); 89 else 90 assert(setsockopt(s, IPPROTO_IP, IP_MULTICAST_IF, &in, 91 sizeof(in)) == 0); 92 if (sendto(s, argv[6], strlen(argv[6]) + 1, 0, (struct sockaddr *)&dst, 93 sizeof(dst)) != (ssize_t)strlen(argv[6]) + 1) 94 err(1, "sendto failed"); 95 96 return (0); 97 } 98