1 #include <sys/types.h>
2 #include <sys/socket.h>
3
4 #include <arpa/inet.h>
5 #include <net/if.h>
6 #include <netinet/in.h>
7
8 #include <err.h>
9 #include <stdint.h>
10 #include <stdio.h>
11 #include <stdlib.h>
12 #include <string.h>
13 #include <unistd.h>
14
15 static void
usage(const char * cmd)16 usage(const char *cmd)
17 {
18 fprintf(stderr, "%s -p port -d dst (-i addr [-m] | -I iface) "
19 "[-P bind_port]\n", cmd);
20 exit(1);
21 }
22
23 int
main(int argc,char * argv[])24 main(int argc, char *argv[])
25 {
26 struct sockaddr_in dst, local_in;
27 struct in_addr iface, mcast_if;
28 int s, opt, n, loop = 0, use_mreq = 0, iface_idx;
29 uint8_t buf[18];
30 socklen_t mcast_if_len;
31 char mcast_if_str[INET_ADDRSTRLEN];
32
33 memset(&dst, 0, sizeof(dst));
34 dst.sin_family = AF_INET;
35
36 memset(&local_in, 0, sizeof(local_in));
37 local_in.sin_family = AF_INET;
38
39 memset(&iface, 0, sizeof(iface));
40 iface_idx = -1;
41
42 while ((opt = getopt(argc, argv, "I:P:d:i:mp:")) != -1) {
43 switch (opt) {
44 case 'I':
45 iface_idx = if_nametoindex(optarg);
46 break;
47
48 case 'P':
49 local_in.sin_port = strtol(optarg, NULL, 10);
50 local_in.sin_port = htons(local_in.sin_port);
51 break;
52
53 case 'd':
54 if (inet_pton(AF_INET, optarg, &dst.sin_addr) <= 0)
55 usage(argv[0]);
56 break;
57
58 case 'i':
59 if (inet_pton(AF_INET, optarg, &iface) <= 0)
60 usage(argv[0]);
61 break;
62
63 case 'm':
64 use_mreq = 1;
65 break;
66
67 case 'p':
68 dst.sin_port = strtol(optarg, NULL, 10);
69 dst.sin_port = htons(dst.sin_port);
70 break;
71
72 default:
73 usage(argv[0]);
74 }
75 }
76
77 if ((iface.s_addr == INADDR_ANY && iface_idx < 0) ||
78 dst.sin_addr.s_addr == INADDR_ANY || dst.sin_port == 0)
79 usage(argv[0]);
80
81 s = socket(AF_INET, SOCK_DGRAM, 0);
82 if (s < 0)
83 err(2, "socket failed");
84
85 if (iface_idx >= 0) {
86 struct ip_mreqn mreqn;
87
88 fprintf(stderr, "ip_mreqn mcast_if ifindex %d\n", iface_idx);
89 memset(&mreqn, 0, sizeof(mreqn));
90 mreqn.imr_address = iface;
91 mreqn.imr_ifindex = iface_idx;
92 if (setsockopt(s, IPPROTO_IP, IP_MULTICAST_IF,
93 &mreqn, sizeof(mreqn)) < 0)
94 err(2, "setsockopt IP_MULTICAST_IF ip_mreqn failed");
95 } else if (use_mreq) {
96 struct ip_mreq mreq;
97
98 fprintf(stderr, "ip_mreq mcast_if\n");
99 memset(&mreq, 0, sizeof(mreq));
100 mreq.imr_interface = iface;
101 if (setsockopt(s, IPPROTO_IP, IP_MULTICAST_IF,
102 &mreq, sizeof(mreq)) < 0)
103 err(2, "setsockopt IP_MULTICAST_IF ip_mreq failed");
104 } else {
105 if (setsockopt(s, IPPROTO_IP, IP_MULTICAST_IF,
106 &iface, sizeof(iface)) < 0)
107 err(2, "setsockopt IP_MULTICAST_IF inaddr failed");
108 }
109
110 mcast_if_len = sizeof(mcast_if);
111 if (getsockopt(s, IPPROTO_IP, IP_MULTICAST_IF,
112 &mcast_if, &mcast_if_len) < 0)
113 err(2, "getsockopt IP_MULTICAST_IF failed");
114 fprintf(stderr, "ifindex %s\n", inet_ntop(AF_INET, &mcast_if,
115 mcast_if_str, sizeof(mcast_if_str)));
116
117 if (setsockopt(s, IPPROTO_IP, IP_MULTICAST_LOOP,
118 &loop, sizeof(loop)) < 0)
119 err(2, "setsockopt IP_MULTICAST_LOOP failed");
120
121 if (local_in.sin_port != 0) {
122 local_in.sin_addr = iface;
123 if (bind(s, (const struct sockaddr *)&local_in,
124 sizeof(local_in)) < 0)
125 err(2, "bind failed");
126 }
127
128 n = sendto(s, buf, sizeof(buf), 0,
129 (const struct sockaddr *)&dst, sizeof(dst));
130 if (n < 0)
131 err(2, "sendto failed");
132 else if (n < (int)sizeof(buf))
133 errx(2, "sent truncated data %d", n);
134
135 exit(0);
136 }
137