#include <windows.h>
#include <winsock.h>
#include <stdio.h>

#define LOCAL_SERVER_PORT 6000
#define MAX_MSG 100

int message_length = 0;



void msg_err_exit(char *msg)
{
    fprintf(stderr, msg);
    system("PAUSE");
    exit(EXIT_FAILURE);
}

int main(int argc, char *argv[]) {
  
  int sd, sd2, rc, n, cliLen;
  struct sockaddr_in cliAddr, remoteServAddr, servAddr;
  char msg[MAX_MSG], value, broadcast_ip[32];

  WSADATA wsaData;
        
  WSAStartup(MAKEWORD(2,1),&wsaData);
  LPHOSTENT lpHostEntry;
  
//obtendo o endereço de broadcast da rede
printf("IP de broadcast da rede: ");
    scanf("%s", broadcast_ip);
    fflush(stdin);
  
/* criando socket de recepção - server */
  sd=socket(AF_INET, SOCK_DGRAM, 0);
  if(sd<0) {
    printf("valor de sd: %d",sd);
    printf("%s: cannot open socket \n",argv[0]);
    exit(1);
  }

  /* bind local server port */
  servAddr.sin_family = AF_INET;
  servAddr.sin_addr.s_addr = htonl(INADDR_ANY);
  servAddr.sin_port = htons(LOCAL_SERVER_PORT);
  rc = bind (sd, (struct sockaddr *) &servAddr,sizeof(servAddr));
  if(rc<0) {
    printf("%s: cannot bind port number %d \n", 
	   argv[0], LOCAL_SERVER_PORT);
    exit(1);
  }

  printf("%s: waiting for data on port UDP %u\n", 
	   argv[0],LOCAL_SERVER_PORT);

  /* server infinite loop */
  while(1) {
    
    /* init buffer */
    memset(msg,0x0,MAX_MSG);


    /* receive message */
    cliLen = sizeof(cliAddr);
    n = recvfrom(sd, msg, MAX_MSG, 0, 
		 (struct sockaddr *) &cliAddr, &cliLen);

    if(n<0) {
      printf("%s: cannot receive data \n",argv[0]);
      continue;
    }
      
    /* print received message */
    printf("%s: from %s:UDP%u : %s \n", 
	   argv[0],inet_ntoa(cliAddr.sin_addr),
	   ntohs(cliAddr.sin_port),msg);
	   
	   
//############################################################################	   
//                                                                                  
//  criando socket para reenvio dos dados aos clientes                                                                                                                                                               
//
//############################################################################     
       message_length = strlen(msg);
       sd2 = socket(AF_INET,SOCK_DGRAM,0);
         if(sd2<0) {
    
                   msg_err_exit("não é possivel abrir socket");
                   }
                   else
                   {
                       puts("socket aberto");
                       }
                       //criando o socket de retorno para o cliente (socket cliente)
                     /* bind any port */
                       memset(&remoteServAddr, 0, sizeof(remoteServAddr));
                       value = '1';
                       if(setsockopt(sd2,SOL_SOCKET,SO_BROADCAST,&value,sizeof(value)) ==-1)
                       {
                         msg_err_exit("opcao broadcast falhou");
                         }

                       lpHostEntry = gethostbyname(broadcast_ip);
                       remoteServAddr.sin_family = AF_INET;
                         remoteServAddr.sin_addr.s_addr = htonl(INADDR_ANY);
                           remoteServAddr.sin_port = htons(5000);
  
                          remoteServAddr.sin_addr = *((LPIN_ADDR)*lpHostEntry->h_addr_list);
                          message_length = strlen(msg);
                        
                        
    rc = sendto(sd, msg, message_length, 0, 
		(LPSOCKADDR) &remoteServAddr, 
		sizeof(struct sockaddr));
    if(rc<0) {
      puts("data not send!");
      WSACleanup();
      closesocket(sd);
      msg_err_exit("socket() failed\n");
    }
       
       
	  if(rc<0) {
      puts("data not send!");
      WSACleanup();
      closesocket(sd2);
      msg_err_exit("socket() failed\n");
      }
      closesocket(sd2);
 
//########################################################################
  }/* end of server infinite loop */
 closesocket(sd);
 WSACleanup();

return 0;

}