mcast.cc

initial working phase of the design of said editor, featuring multicasting, advanced linux keyboard

#include "queue.h"
#include "kbd.h"

#include <fcntl.h>			// fcntl
#include <sys/socket.h>
#include <netinet/in.h>			// sockaddr_in
#include <arpa/inet.h>
#include <netdb.h>
#include <netinet/ip.h>			// iphdr
#include <netinet/udp.h>		// udphdr

#include <unistd.h>			// getpid
#include <stdio.h>			// printf
/*
#include <net/if.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
*/

extern queue* q;
extern int ms; // multicast socket
extern struct sockaddr_in to;
extern u_int id;

int init_mcast_socket()
{
   struct sockaddr_in sin; // address for bind
   sin.sin_addr.s_addr = htonl( INADDR_ANY );
   sin.sin_port = htons( 9876 );

   ms = socket( PF_INET, SOCK_DGRAM, 0 );

   int flags = fcntl( ms, F_GETFL, 0 );
   if( flags == -1 ) printf( "bad flags.\n" );
   fcntl( ms, F_SETFL, flags | O_ASYNC | O_NONBLOCK );
   fcntl( ms, F_SETOWN, getpid() );

   int msock_reuse = 1;
   setsockopt( ms, SOL_SOCKET, SO_REUSEADDR, &msock_reuse, sizeof( int ) );

   bind( ms, ( struct sockaddr* )&sin, sizeof( sin ) );
  
   u_char msock_ttl = 4;
   setsockopt( ms, IPPROTO_IP, IP_MULTICAST_TTL,
      &msock_ttl, sizeof( u_char ) );
   u_char msock_loop = 1;
   setsockopt( ms, IPPROTO_IP, IP_MULTICAST_LOOP,
      &msock_loop, sizeof( u_char ) );

   struct ip_mreq mreq; // multicast request
   struct hostent* multi = gethostbyname( "224.4.78.1" );
   mreq.imr_multiaddr.s_addr = *( u_int* )( multi -> h_addr );
//   struct hostent* local = gethostbyname( "192.168.0.1" );
   mreq.imr_interface.s_addr = INADDR_ANY;
//   mreq.imr_interface.s_addr = *( u_int* )local -> h_addr;

   to.sin_addr = mreq.imr_multiaddr;
   to.sin_port = htons( 9876 );
   to.sin_family = AF_INET;

   printf( "address: %s:%d\r\n", inet_ntoa( mreq.imr_multiaddr ), 9876 );
   fflush( stdout );
  
   if( setsockopt( ms, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq, sizeof( mreq ) )
   < 0 ) printf( "failed\n" );
     
   return ms;
}