#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#define MAX_LEN 1024
int main(int argc, char *argv[])
{
int sock;
char message_to_send[MAX_LEN];
unsigned int send_len;
char* multicast_ip;
unsigned short multicast_port;
unsigned char multicast_ttl=1;
struct sockaddr_in multicast_addr;
if (argc != 3)
{
fprintf(stderr, "Usage: %s Multicast_IP Multicast_Port\n", argv[0]);
exit(1);
}
multicast_ip = argv[1]; /* arg 1: multicast IP address */
multicast_port = atoi(argv[2]); /* arg 2: multicast port number */
/* create a socket */
if ((sock = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0)
{
perror("Socket creation failed");
exit(1);
}
/* set the TTL (time to live/hop count) for the send */
if ((setsockopt(sock, IPPROTO_IP, IP_MULTICAST_TTL, (void*) &multicast_ttl, sizeof(multicast_ttl))) < 0)
{
perror("setsockopt() failed");
exit(1);
}
memset(&multicast_addr, 0, sizeof(multicast_addr));
multicast_addr.sin_family = AF_INET;
multicast_addr.sin_addr.s_addr = inet_addr(multicast_ip);
multicast_addr.sin_port = htons(multicast_port);
printf("Type the message below (Press Enter to send, ctrl-C to quit):\n");
memset(message_to_send, 0, sizeof(message_to_send));
while (fgets(message_to_send, MAX_LEN, stdin))
{
send_len = strlen(message_to_send);
if ((sendto(sock, message_to_send, send_len, 0,
(struct sockaddr *) &multicast_addr,
sizeof(multicast_addr))) != send_len)
{
perror("Error in number of bytes");
exit(1);
}
memset(message_to_send, 0, sizeof(message_to_send));
}
close(sock);
exit(0);
}