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
atop(const char * c)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
main(int argc,char * argv[])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