rxsock.c

   1 /*
   2     receive multicast socket test
   3     by inkling@nop.org 2-dec-2005
   4     released to public domain
   5 */
   6
   7 #include <stdio.h>
   8 #include <stdlib.h>
   9 #include <unistd.h>
  10 #include <sys/socket.h>
  11 #include <netinet/in.h>
  12 #include <arpa/inet.h>
  13 #include <string.h>
  14
  15 #define MULTICAST_ADDRESS "224.1.2.3"
  16 #define MULTICAST_PORT 1234
  17
  18 int
  19 main( int argc, char ** argv)
  20 {
  21     struct sockaddr_in sockin;
  22     struct ip_mreq im;
  23     unsigned char tsbuf[188];
  24     int sockfd, bindok, ruok, imok, bc, rx;
  25     unsigned int yes = 1;
  26     int sockin_len;
  27
  28     bc = 0;
  29     sockin_len = sizeof(sockin);
  30
  31
  32     /* open socket */
  33     sockfd = socket( AF_INET, SOCK_DGRAM, IPPROTO_UDP );
  34     if (-1 == sockfd) {
  35         perror( "socket open ");
  36         exit(1);
  37     }
  38
  39     /* set socket as re-usable */
  40     ruok = setsockopt( sockfd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(yes));
  41     if (-1 == ruok) {
  42         perror( "socket reuse ");
  43         exit(1);
  44     }
  45
  46     /* set socket as multicast group */
  47     im.imr_multiaddr.s_addr = inet_addr( MULTICAST_ADDRESS );
  48     im.imr_interface.s_addr = htonl( INADDR_ANY );
  49     imok = setsockopt( sockfd, IPPROTO_IP, IP_ADD_MEMBERSHIP, &im, sizeof(im));
  50     if (-1 == imok) {
  51         perror( "socket multicast ");
  52         exit(1);
  53     }
  54
  55     /* bind socket AFTER setting socket options */
  56     /* gives re-use error if you try bind first */
  57     memset( &sockin, 0, sockin_len );
  58     sockin.sin_family = AF_INET;
  59     sockin.sin_addr.s_addr = htonl( INADDR_ANY );
  60     sockin.sin_port = htons( MULTICAST_PORT );
  61     bindok = bind( sockfd, (struct sockaddr *)&sockin,  sockin_len );
  62     if (-1 == bindok) {
  63         perror( "socket bind ");
  64         exit(1);
  65     }
  66     while(1) {
  67 /*      memset( &sockin, 0, sizeof(sockin) ); */
  68         rx = recvfrom( sockfd,
  69                         tsbuf, sizeof(tsbuf),
  70                         0,
  71                         (struct sockaddr *)&sockin,
  72                         &sockin_len
  73                         );
  74
  75         if( -1 == rx) {
  76             perror( "recvfrom ");
  77             exit(1);
  78         }
  79
  80         bc += rx;
  81         fprintf( stdout, "received %d bytes %d total\n", rx, bc);
  82     }
  83
  84     return 0;
  85 }