#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
char *hostname = "192.168.0.1" ;
char *multicase = "224.10.201.1" ;
char *localip = "192.168.0.2" ;
int port = 6789 ;
int main()
{
struct ip_mreq command ;
int loop = 1 ;
int iter = 0 ;
int sin_len ;
char message[256] = "" ;
int socket_des ;
struct sockaddr_in sin ;
struct hostent *server_host_name ;
if ( (server_host_name = gethostbyname(hostname)) == 0 )
{
printf("gethostbyname error\n") ;
exit(EXIT_FAILURE) ;
}
bzero(&sin,sizeof(sin)) ;
sin.sin_family = AF_INET ;
sin.sin_addr.s_addr = inet_addr(localip) ;
sin.sin_port = htons(port) ;
if ( (socket_des = socket(AF_INET,SOCK_DGRAM,0)) == -1 )
{
printf("create socket error\n") ;
exit(EXIT_FAILURE) ;
}
loop = 1 ;
if ( setsockopt(socket_des,SOL_SOCKET,SO_REUSEADDR,&loop,sizeof(loop))<0)
{
printf("setsockopt:SO_REUSEADDR\n") ;
exit(EXIT_FAILURE) ;
}
if ( bind(socket_des,(struct sockaddr*)&sin,sizeof(sin)) < 0 )
{
printf("bind error\n") ;
exit(EXIT_FAILURE) ;
}
loop = 1 ;
if ( setsockopt(socket_des,IPPROTO_IP,IP_MULTICAST_LOOP,&loop,sizeof(loop))<0)
{
printf("setsockopt:IP_MULTICAST_LOOP\n") ;
exit(EXIT_FAILURE) ;
}
command.imr_multiaddr.s_addr = inet_addr(multicase) ;
command.imr_interface.s_addr = inet_addr(localip) ;
if ( command.imr_multiaddr.s_addr == -1 )
{
printf("%s not a legal multicast address\n",multicase) ;
exit(EXIT_FAILURE) ;
}
if ( setsockopt(socket_des,IPPROTO_IP,IP_ADD_MEMBERSHIP,(char*)&command,sizeof(command)) < 0 )
{
printf("setsocketopt:IP_ADD_MEMBERSHIP\n") ;
exit(EXIT_FAILURE) ;
}
while(iter++ < 10)
{
sin_len = sizeof(sin) ;
if ( recvfrom(socket_des,message,256,0,(struct sockaddr*)&sin,&sin_len) == -1 )
{
printf("recv error\n") ;
exit(EXIT_FAILURE) ;
}
printf("Response #%-2d from server:%s\n",iter,message) ;
sleep(2) ;
}
if ( setsockopt(socket_des,IPPROTO_IP,IP_DROP_MEMBERSHIP,&command,sizeof(command)) < 0 )
{
printf("setsockopt:IP_DROP_MEMBERSHIP\n") ;
exit(EXIT_FAILURE) ;
}
close(socket_des) ;
exit(EXIT_SUCCESS) ;
}
