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 <netinet/ip.h> 31 #include <arpa/inet.h> 32 #include <net/if.h> 33 #include <assert.h> 34 #include <errno.h> 35 #include <stdbool.h> 36 #include <stdio.h> 37 #include <stdlib.h> 38 #include <string.h> 39 #include <limits.h> 40 #include <err.h> 41 42 static in_port_t 43 atop(const char *c) 44 { 45 unsigned long ul; 46 47 errno = 0; 48 if ((ul = strtol(c, NULL, 10)) < 1 || ul > IPPORT_MAX || errno != 0) 49 err(1, "can't parse %s", c); 50 51 return ((in_port_t)ul); 52 } 53 54 int 55 main(int argc, char *argv[]) 56 { 57 char buf[IP_MAXPACKET + 1]; 58 struct sockaddr_in sin = { 59 .sin_family = AF_INET, 60 .sin_len = sizeof(struct sockaddr_in), 61 }; 62 socklen_t slen = sizeof(struct sockaddr_in); 63 struct in_addr maddr, ifaddr; 64 ssize_t len; 65 int s, ifindex; 66 bool index; 67 68 if (argc < 4) 69 usage: 70 errx(1, "Usage: %s (ip_mreq|ip_mreqn|group_req) " 71 "IPv4-group port interface", argv[0]); 72 73 if (inet_pton(AF_INET, argv[2], &maddr) != 1) 74 err(1, "inet_pton(%s) failed", argv[2]); 75 sin.sin_port = htons(atop(argv[3])); 76 if (inet_pton(AF_INET, argv[4], &ifaddr) == 1) 77 index = false; 78 else if ((ifindex = if_nametoindex(argv[4])) > 0) 79 index = true; 80 else if (strcmp(argv[4], "0") == 0) { 81 ifindex = 0; 82 index = true; 83 } else 84 err(1, "if_nametoindex(%s) failed", argv[4]); 85 86 assert((s = socket(PF_INET, SOCK_DGRAM, 0)) > 0); 87 assert(bind(s, (struct sockaddr *)&sin, sizeof(sin)) == 0); 88 89 if (strcmp(argv[1], "ip_mreq") == 0) { 90 if (index) 91 errx(1, "ip_mreq doesn't accept index"); 92 struct ip_mreq mreq = { 93 .imr_multiaddr = maddr, 94 .imr_interface = ifaddr, 95 }; 96 assert(setsockopt(s, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq, 97 sizeof(mreq)) == 0); 98 } else if (strcmp(argv[1], "ip_mreqn") == 0) { 99 /* 100 * ip_mreqn shall be used with index, but for testing 101 * purposes accept address too. 102 */ 103 struct ip_mreqn mreqn = { 104 .imr_multiaddr = maddr, 105 .imr_address = index ? (struct in_addr){ 0 } : ifaddr, 106 .imr_ifindex = index ? ifindex : 0, 107 }; 108 assert(setsockopt(s, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreqn, 109 sizeof(mreqn)) == 0); 110 } else if (strcmp(argv[1], "group_req") == 0) { 111 if (!index) 112 errx(1, "group_req expects index"); 113 struct group_req greq = { .gr_interface = ifindex }; 114 struct sockaddr_in *gsa = (struct sockaddr_in *)&greq.gr_group; 115 116 gsa->sin_family = AF_INET; 117 gsa->sin_len = sizeof(struct sockaddr_in); 118 gsa->sin_addr = maddr; 119 assert(setsockopt(s, IPPROTO_IP, MCAST_JOIN_GROUP, &greq, 120 sizeof(greq)) == 0); 121 } else 122 goto usage; 123 124 assert((len = recvfrom(s, buf, sizeof(buf) - 1, 0, 125 (struct sockaddr *)&sin, &slen)) > 0); 126 buf[len] = '\0'; 127 printf("%s:%u %s\n", inet_ntoa(sin.sin_addr), ntohs(sin.sin_port), buf); 128 129 return (0); 130 } 131