Hi,

One of my multicast program dies on a specific set of machines with error No
such Device when I try to join the multicast group with
setsockopt(sock, IPPROTO_IP, IP_ADD_MEMBERSHIP, ...);
The machines in question are running RHEL 3.0 (2.4.21-4ELsmp) and I also
checked to find that multicast is enabled. Any pointers to resolve the issue
is appreciated. I have attached a test program that reproduces the error.

Thanks!


#include <stdio.h>
#include <stdlib.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <errno.h>
#include <string.h>

int main(void)
{
int sock;
int one;
int ret;
struct sockaddr_in sock_addr;
struct hostent *hent;
struct ip_mreqn mreq;

sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP);
if(sock < 0)
{
perror("\nError in socket creation");
exit(errno);
}
memset(&sock_addr, 0, sizeof(sock_addr));
sock_addr.sin_family = AF_INET;
sock_addr.sin_addr.s_addr = htonl(INADDR_ANY);
sock_addr.sin_port = 0;

one = 1;
ret = setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (char *)&one,
sizeof(one));
if(ret < 0)
{
perror("\nError in reusing addr");
exit(errno);
}

ret = bind(sock, (struct sockaddr *)&sock_addr, sizeof(sock_addr));
if(ret < 0)
{
perror("\nError in bind");
exit(errno);
}

hent = gethostbyname("224.1.1.11");
if(!hent)
{
perror("\nInvalid address");
exit(errno);
}

memset(&sock_addr, 0, sizeof(sock_addr));
sock_addr.sin_family = AF_INET;
memcpy(&sock_addr.sin_addr.s_addr, hent->h_addr, hent->h_length);
if(!IN_MULTICAST(ntohl(sock_addr.sin_addr.s_addr)) )
{
perror("\nInvalid address");
exit(errno);
}

/* Join the multicast group */
memset(&mreq, 0, sizeof(mreq));
mreq.imr_multiaddr.s_addr = sock_addr.sin_addr.s_addr;
mreq.imr_address.s_addr = htonl(INADDR_ANY);
ret = setsockopt(sock, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq,
sizeof(mreq));
if(ret<0)
{
perror("\nCannot join multicast group");
exit(errno);
}

return 0;
}