1 #include <sys/types.h> 2 #include <sys/socket.h> 3 4 #include <arpa/inet.h> 5 #include <netinet/in.h> 6 7 #include <errno.h> 8 #include <stdio.h> 9 #include <stdlib.h> 10 #include <string.h> 11 #include <unistd.h> 12 13 static void 14 usage(const char *cmd) 15 { 16 fprintf(stderr, 17 "%s -m addr -p port [-d dst] [-i addr] [-D delay]\n", cmd); 18 exit(1); 19 } 20 21 int 22 main(int argc, char *argv[]) 23 { 24 struct ip_mreq mreq; 25 struct sockaddr_in in, dst; 26 struct in_addr iface; 27 int s, opt, n, delay; 28 29 memset(&in, 0, sizeof(in)); 30 in.sin_family = AF_INET; 31 32 memset(&dst, 0, sizeof(dst)); 33 dst.sin_family = AF_INET; 34 35 memset(&iface, 0, sizeof(iface)); 36 delay = 0; 37 38 while ((opt = getopt(argc, argv, "m:p:d:i:D:")) != -1) { 39 switch (opt) { 40 case 'm': 41 if (inet_pton(AF_INET, optarg, &in.sin_addr) <= 0) { 42 fprintf(stderr, "invalid -m addr %s\n", optarg); 43 exit(1); 44 } 45 break; 46 47 case 'p': 48 in.sin_port = htons(atoi(optarg)); 49 dst.sin_port = in.sin_port; 50 break; 51 52 case 'd': 53 if (inet_pton(AF_INET, optarg, &dst.sin_addr) <= 0) { 54 fprintf(stderr, "invalid -d addr %s\n", optarg); 55 exit(1); 56 } 57 break; 58 59 case 'i': 60 if (inet_pton(AF_INET, optarg, &iface) <= 0) { 61 fprintf(stderr, "invalid -i addr %s\n", optarg); 62 exit(1); 63 } 64 break; 65 66 case 'D': 67 delay = atoi(optarg); 68 break; 69 70 default: 71 usage(argv[0]); 72 } 73 } 74 75 if (in.sin_addr.s_addr == INADDR_ANY || in.sin_port == 0) 76 usage(argv[0]); 77 if (dst.sin_addr.s_addr == 0) 78 dst.sin_addr = in.sin_addr; 79 80 s = socket(AF_INET, SOCK_DGRAM, 0); 81 if (s < 0) { 82 fprintf(stderr, "socket failed: %d\n", errno); 83 exit(1); 84 } 85 86 if (bind(s, (const struct sockaddr *)&in, sizeof(in)) < 0) { 87 fprintf(stderr, "bind failed: %d\n", errno); 88 exit(1); 89 } 90 91 memset(&mreq, 0, sizeof(mreq)); 92 mreq.imr_multiaddr = in.sin_addr; 93 mreq.imr_interface = iface; 94 if (setsockopt(s, IPPROTO_IP, IP_ADD_MEMBERSHIP, 95 &mreq, sizeof(mreq)) < 0) { 96 fprintf(stderr, "setsockopt IP MEMSHIP failed: %d\n", errno); 97 exit(1); 98 } 99 100 if (iface.s_addr != INADDR_ANY) { 101 if (setsockopt(s, IPPROTO_IP, IP_MULTICAST_IF, 102 &iface, sizeof(iface)) < 0) { 103 fprintf(stderr, "setsockopt IP IF failed: %d\n", errno); 104 exit(1); 105 } 106 } 107 108 if (delay > 0) 109 sleep(delay); 110 111 n = sendto(s, &mreq, sizeof(mreq), 0, 112 (const struct sockaddr *)&dst, sizeof(dst)); 113 if (n < 0) { 114 fprintf(stderr, "sendto failed: %d\n", errno); 115 exit(1); 116 } 117 118 exit(0); 119 } 120