/* dgmcsend.c */

/* Demonstates the use of multicast send for datagram transfer */

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <stdio.h>

char buf[100];
struct hostent *hp;
struct hostent *gethostbyname();
struct sockaddr_in name;
struct sockaddr_in sname;
int namelen;
struct ip_mreq mreq;

/* unsigned char mgroup[4] = {0xe0, 0x00, 0x00, 0xe0}; */

unsigned char mgroup[4] = {0xe0, 0x02, 0x7f, 0xfe};
int on=1;

main(argc, argv)
int argc;
char *argv[];
{
   int i;
   unsigned char c;
   int sock;
   int netaddr;
   int status;

/* Create datagram socket */

   sock = socket(PF_INET, SOCK_DGRAM, 0);
   if (sock < 0)
   {
      printf("Socket create failed \n");
      exit(1);
   }

/* Get host network address from command line parm */

   hp = gethostbyname(argv[1]);
   if (hp == 0)
   {
      printf("Host %s not found\n", argv[1]);
      exit(1);
   }


   bcopy((char *)hp->h_addr, &mreq.imr_interface, 4);
   bcopy((char *)mgroup, &mreq.imr_multiaddr, 4);

   status =  setsockopt(sock, SOL_SOCKET, SO_REUSEADDR,
                             (char *)&on, sizeof(on));
   if (status < 0)
      printf("Set reuse  failed with %d \n", status);

   status =  setsockopt(sock, 0     , IP_ADD_MEMBERSHIP,
                             (char *)&mreq, sizeof(mreq));

   if (status < 0)
      printf("Set sockopt failed with %d \n", status);
   printf("Join multicast status is %d \n", status);

/* Fill in protocol family and port # from command line then */
/* bind the socket to the specified address.                 */

   name.sin_family = AF_INET;
   name.sin_port = htons(atoi(argv[2]));
   bcopy((char *)mgroup,
             (char *)&name.sin_addr, 4);

   status = bind(sock, (struct sockaddr *)&name, sizeof(name));
   printf("Bind status = %d \n", status);
   if (status < 0)
     exit(1);

   printf("Dest net address = ");
   for (i = 0; i < hp->h_length; i++)
   {
      c = *((char *)&name.sin_addr + i);
      printf(" %2x", c);
   }
   status = sendto(sock, "This is a multicast\n", 20, 0,
                    &name, sizeof(name));
   printf("%d bytes sent \n", status);

   exit(1);

/* Wait for someone to send me a datagram.. I should receive my own */

   namelen = sizeof(struct sockaddr_in);
   status = recvfrom(sock, buf, sizeof(buf), 0,
               (struct sockaddr *)&sname, &namelen);

   printf("status = %d \n", status);
   printf("Msg = %s \n", buf);

   printf("Sender net address = ");
   for (i = 0; i < hp->h_length; i++)
   {
      c = *((char *)&sname.sin_addr + i);
      printf(" %2x", c);
   }
   printf("\n");
   printf("Sender port address = %x \n", sname.sin_port);
}