1 #include <sys/types.h> 2 #include <sys/socket.h> 3 4 #include <arpa/inet.h> 5 #include <netinet/in.h> 6 7 #include <err.h> 8 #include <stdint.h> 9 #include <stdio.h> 10 #include <stdlib.h> 11 #include <string.h> 12 #include <unistd.h> 13 14 static void 15 usage(const char *cmd) 16 { 17 fprintf(stderr, "%s -p port -d dst -i addr [-P bind_port]\n", cmd); 18 exit(1); 19 } 20 21 int 22 main(int argc, char *argv[]) 23 { 24 struct sockaddr_in dst, local_in; 25 struct in_addr iface; 26 int s, opt, n, loop = 0; 27 uint8_t buf[18]; 28 29 memset(&dst, 0, sizeof(dst)); 30 dst.sin_family = AF_INET; 31 32 memset(&local_in, 0, sizeof(local_in)); 33 local_in.sin_family = AF_INET; 34 35 memset(&iface, 0, sizeof(iface)); 36 37 while ((opt = getopt(argc, argv, "P:d:i:p:")) != -1) { 38 switch (opt) { 39 case 'P': 40 local_in.sin_port = strtol(optarg, NULL, 10); 41 local_in.sin_port = htons(local_in.sin_port); 42 break; 43 44 case 'd': 45 if (inet_pton(AF_INET, optarg, &dst.sin_addr) <= 0) 46 usage(argv[0]); 47 break; 48 49 case 'i': 50 if (inet_pton(AF_INET, optarg, &iface) <= 0) 51 usage(argv[0]); 52 break; 53 54 case 'p': 55 dst.sin_port = strtol(optarg, NULL, 10); 56 dst.sin_port = htons(dst.sin_port); 57 break; 58 59 default: 60 usage(argv[0]); 61 } 62 } 63 64 if (iface.s_addr == INADDR_ANY || 65 dst.sin_addr.s_addr == INADDR_ANY || dst.sin_port == 0) 66 usage(argv[0]); 67 68 s = socket(AF_INET, SOCK_DGRAM, 0); 69 if (s < 0) 70 err(2, "socket failed"); 71 72 if (setsockopt(s, IPPROTO_IP, IP_MULTICAST_IF, 73 &iface, sizeof(iface)) < 0) 74 err(2, "setsockopt IP_MULTICAST_IF failed"); 75 76 if (setsockopt(s, IPPROTO_IP, IP_MULTICAST_LOOP, 77 &loop, sizeof(loop)) < 0) 78 err(2, "setsockopt IP_MULTICAST_LOOP failed"); 79 80 if (local_in.sin_port != 0) { 81 local_in.sin_addr = iface; 82 if (bind(s, (const struct sockaddr *)&local_in, 83 sizeof(local_in)) < 0) 84 err(2, "bind failed"); 85 } 86 87 n = sendto(s, buf, sizeof(buf), 0, 88 (const struct sockaddr *)&dst, sizeof(dst)); 89 if (n < 0) 90 err(2, "sendto failed"); 91 else if (n < (int)sizeof(buf)) 92 errx(2, "sent truncated data %d", n); 93 94 exit(0); 95 } 96