Hello World UDP multicast not working - c++

Question

I am trying to get a very basic hello world UDP sender and UDP multicast listener to work. I have a PC but have a virtual machine with the Linux OS CentOS. It has no problems connecting to the internet. The sender and listener are two separate programs, Eclipse is my environment.
The Sender...
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <time.h>
#include <string.h>
#include <stdio.h>
#include <unistd.h>
#define UDP_PORT 5403
#define UDP_GROUP "225.0.0.1" // 127.0.0.1
int main(int argc, char *argv[])
{
struct sockaddr_in addr;
int fd;
struct ip_mreq mreq;
char *message="Hello, World!";
int message_size = strlen(message) + 1;
// Create a UDP socket
fd = socket(AF_INET, SOCK_DGRAM, 0);
if (fd < 0)
{
perror("socket(...) ");
return -1;
}
// allow multiple sockets to use the same PORT number
u_int reuse_port = 1;
if (setsockopt(fd, IPPROTO_IP, IP_MULTICAST_LOOP, &reuse_port, sizeof(reuse_port)) < 0)
{
perror("setsockopt(...) ");
return -1;
}
// set up destination address
memset(&addr, 0, sizeof(addr));
addr.sin_family = AF_INET;
addr.sin_addr.s_addr = inet_addr(UDP_GROUP);
addr.sin_port = htons(UDP_PORT);
printf("Begin sendto(...) infinite loop\n");
while (true)
{
printf("Sending message: %s, of size: %d\n", message, message_size);
if (sendto(fd, message, message_size, 0, (struct sockaddr *)&addr, sizeof(addr)) < 0)
{
perror("sendto(...): ");
return -1;
}
// printf("message sent: %s\n", message);
sleep(1);
}
return 1;
}
The Listener...
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <time.h>
#include <string.h>
#include <stdio.h>
#define UDP_PORT 5403
#define UDP_GROUP "225.0.0.1"
#define MAX_BUFFER_SIZE 256
int main(int argc, char *argv[])
{
struct sockaddr_in addr;
int fd, nbytes;
socklen_t addrlen;
struct ip_mreq mreq;
char msgbuf[MAX_BUFFER_SIZE];
u_int reuse_port = 1;
// Create a socket
fd = socket(AF_INET,SOCK_DGRAM,0);
if (fd < 0)
{
perror("create socket failed");
return -1;
}
// allow multiple sockets to use the same PORT number
if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &reuse_port, sizeof(reuse_port)) < 0)
{
perror("Reusing port number failed");
return -1;
}
// set up destination address
memset(&addr, 0, sizeof(addr));
addr.sin_family = AF_INET;
addr.sin_addr.s_addr = htonl(INADDR_ANY);
addr.sin_port = htons(UDP_PORT);
if (bind(fd, (struct sockaddr *)&addr, sizeof(addr)) < 0)
{
perror("bind");
return -1;
}
// Set the recvfrom timeout after 1 s
struct timeval tv;
tv.tv_sec = 2;
tv.tv_usec = 0;
if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv)) < 0)
{
perror("Error setting recvfrom timeout\n");
return -1;
}
// use setsockopt() to request that the kernel join a multicast group
mreq.imr_multiaddr.s_addr = inet_addr(UDP_GROUP);
mreq.imr_interface.s_addr = htonl(INADDR_ANY);
if (setsockopt(fd, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq, sizeof(mreq)) < 0)
{
perror("setsockopt");
return -1;
}
addrlen = sizeof(addr);
printf("Begin recvfrom(...) infinite loop\n");
while (true)
{
nbytes = recvfrom(fd, msgbuf, MAX_BUFFER_SIZE, 0, (struct sockaddr *)&addr, &addrlen);
if (nbytes < 0)
{
printf("recvfrom timeout\n");
}
else
{
printf("message received: %s\n", msgbuf);
}
}
return 1;
}
Every second, the sender program printf's "Sending message: Hello, World!, of size: 14" and every two seconds the receiver printf's "recvfrom timeout". I have set Wireshark to look at UDP traffic and I definitely see the sento data. The recvfrom is not getting any data. I have tried using many different Group IP's from 255.0.0.0 to 239.255.255.255, no change. I have tried many different ports, no change. Is their a special setup I need to do on my network card? I'm not sure what else to do. Small edit, the recvfrom and sendto message should not have "&".