mcastserver.c File Reference

#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <stdio.h>
#include <stdlib.h>

Include dependency graph for mcastserver.c:

Functions
int	main (int argc, char *argv[])

Variables
struct in_addr	localInterface
struct sockaddr_in	groupSock
int	sd
char	databuf [1024] = "Multicast test message lol!"
int	datalen = sizeof(databuf)

Function Documentation

int main	(	int	argc,
		char *	argv[]
	)

{
/* Create a datagram socket on which to send. */
sd = socket(AF_INET, SOCK_DGRAM, 0);
if(sd < 0)
{
  perror("Opening datagram socket error");
  exit(1);
}
else
  printf("Opening the datagram socket...OK.\n");
 
/* Initialize the group sockaddr structure with a */
/* group address of 225.1.1.1 and port 5555. */
memset((char *) &groupSock, 0, sizeof(groupSock));
groupSock.sin_family = AF_INET;
groupSock.sin_addr.s_addr = inet_addr("225.1.1.1");
groupSock.sin_port = htons(4321);
 
/* Disable loopback so you do not receive your own datagrams.
{
char loopch = 0;
if(setsockopt(sd, IPPROTO_IP, IP_MULTICAST_LOOP, (char *)&loopch, sizeof(loopch)) < 0)
{
perror("Setting IP_MULTICAST_LOOP error");
close(sd);
exit(1);
}
else
printf("Disabling the loopback...OK.\n");
}
*/
 
/* Set local interface for outbound multicast datagrams. */
/* The IP address specified must be associated with a local, */
/* multicast capable interface. */
localInterface.s_addr = inet_addr("127.0.0.1"); //203.106.93.94
if(setsockopt(sd, IPPROTO_IP, IP_MULTICAST_IF, (char *)&localInterface, sizeof(localInterface)) < 0)
{
  perror("Setting local interface error");
  exit(1);
}
else 
{
  printf("Setting the local interface...OK\n");
/* Send a message to the multicast group specified by the*/
/* groupSock sockaddr structure. */
/*int datalen = 1024;*/

int i;

while(1){

if(sendto(sd, databuf, datalen, 0, (struct sockaddr*)&groupSock, sizeof(groupSock)) < 0)
{
    perror("Sending datagram message error");
}
else {
  printf("Sending datagram message...OK\n");
}
    
    usleep(1000000); 
}
 
} // end of else 
 
/* Try the re-read from the socket if the loopback is not disable
if(read(sd, databuf, datalen) < 0)
{
perror("Reading datagram message error\n");
close(sd);
exit(1);
}
else
{
printf("Reading datagram message from client...OK\n");
printf("The message is: %s\n", databuf);
}
*/

return 0;
}

Variable Documentation

struct in_addr localInterface

struct sockaddr_in groupSock

int sd

char databuf[1024] = "Multicast test message lol!"

int datalen = sizeof(databuf)