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 <sysexits.h>
40 #include <limits.h>
41 #include <err.h>
42
43 static in_port_t
atop(const char * c)44 atop(const char *c)
45 {
46 unsigned long ul;
47
48 errno = 0;
49 if ((ul = strtol(c, NULL, 10)) < 1 || ul > IPPORT_MAX || errno != 0)
50 err(1, "can't parse %s", c);
51
52 return ((in_port_t)ul);
53 }
54
55 int
main(int argc,char * argv[])56 main(int argc, char *argv[])
57 {
58 char buf[IP_MAXPACKET + 1];
59 struct sockaddr_in sin = {
60 .sin_family = AF_INET,
61 .sin_len = sizeof(struct sockaddr_in),
62 };
63 socklen_t slen = sizeof(struct sockaddr_in);
64 struct in_addr maddr, ifaddr;
65 ssize_t len;
66 int s, ifindex;
67 bool index;
68
69 if (argc < 4)
70 usage:
71 errx(1, "Usage: %s (ip_mreq|ip_mreqn|group_req) "
72 "IPv4-group port interface", argv[0]);
73
74 if (inet_pton(AF_INET, argv[2], &maddr) != 1)
75 err(1, "inet_pton(%s) failed", argv[2]);
76 sin.sin_port = htons(atop(argv[3]));
77 if (inet_pton(AF_INET, argv[4], &ifaddr) == 1)
78 index = false;
79 else if ((ifindex = if_nametoindex(argv[4])) > 0)
80 index = true;
81 else if (strcmp(argv[4], "0") == 0) {
82 ifindex = 0;
83 index = true;
84 } else
85 err(1, "if_nametoindex(%s) failed", argv[4]);
86
87 assert((s = socket(PF_INET, SOCK_DGRAM, 0)) > 0);
88 assert(bind(s, (struct sockaddr *)&sin, sizeof(sin)) == 0);
89
90 if (strcmp(argv[1], "ip_mreq") == 0) {
91 if (index)
92 errx(1, "ip_mreq doesn't accept index");
93 struct ip_mreq mreq = {
94 .imr_multiaddr = maddr,
95 .imr_interface = ifaddr,
96 };
97 if (setsockopt(s, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq,
98 sizeof(mreq)) != 0)
99 err(EX_OSERR, "setsockopt");
100 } else if (strcmp(argv[1], "ip_mreqn") == 0) {
101 /*
102 * ip_mreqn shall be used with index, but for testing
103 * purposes accept address too.
104 */
105 struct ip_mreqn mreqn = {
106 .imr_multiaddr = maddr,
107 .imr_address = index ? (struct in_addr){ 0 } : ifaddr,
108 .imr_ifindex = index ? ifindex : 0,
109 };
110 if (setsockopt(s, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreqn,
111 sizeof(mreqn)) != 0)
112 err(EX_OSERR, "setsockopt");
113 } else if (strcmp(argv[1], "group_req") == 0) {
114 if (!index)
115 errx(1, "group_req expects index");
116 struct group_req greq = { .gr_interface = ifindex };
117 struct sockaddr_in *gsa = (struct sockaddr_in *)&greq.gr_group;
118
119 gsa->sin_family = AF_INET;
120 gsa->sin_len = sizeof(struct sockaddr_in);
121 gsa->sin_addr = maddr;
122 if (setsockopt(s, IPPROTO_IP, MCAST_JOIN_GROUP, &greq,
123 sizeof(greq)) != 0)
124 err(EX_OSERR, "setsockopt");
125 } else
126 goto usage;
127
128 assert((len = recvfrom(s, buf, sizeof(buf) - 1, 0,
129 (struct sockaddr *)&sin, &slen)) > 0);
130 buf[len] = '\0';
131 printf("%s:%u %s\n", inet_ntoa(sin.sin_addr), ntohs(sin.sin_port), buf);
132
133 return (0);
134 }
135