/* broadcastGet.c - demo for getting a broadcast message */   /* Copyright 1984-1997 Wind River Systems, Inc. */  /* modification history -------------------- 01d,15Sep97,mm   cast arg 2 of bind 01c,15Sep97,mm   defined function broadcastGet 01b,15Sep97,mm   changed "if.h" to "net/if.h", added stdio.h, unistd.h,                   and sockLib.h 01a,08Feb94,ms   cleaned and modified for VxDemo. */  #include "vxWorks.h" #include "types.h" #include "string.h" #include "socket.h" #include "sockLib.h" #include "stdio.h" #include "in.h" #include "net/if.h" #include "ioctl.h" #include "unistd.h"  #define BUFSIZ (sizeof (struct ifreq) * 4)/*size of buffer for SIOCFGIFCONFIG*/  /*****************************************************************************  * broadcastGet - Get the broadcast message   *  * DESCRIPTION  *  *     Demo for getting the broadcast message. Also demonstrates the usage  *     of SIOCGIFCONF ioctl option. This SIOCGIFCONF ioctl option is not needed  *     for broadcasting.    *  * RETURNS: OK or ERROR  *  * EXAMPLE:  *  *     Run broadcastGet task on one VxWorks system as follows  *     before starting the broadcastSend task from another VxWorks system  *     in the same physical network. The other half of the demonstration  *     is in broadcastSend.c.  *  *     -> sp (broadcastGet,  7001)   *  *     where 7001 (port number should be greater than 5000 for user-developed)  *     is an example port number used in this demonstration to receive the  *     broadcast message.  *      *  */  STATUS broadcastGet(int port);  STATUS broadcastGet      (     int port                                          /* port number */           )     {     int sockFd;                   /* socket fd */                        struct sockaddr_in sockAddr;  /* socket address to recv from */      char  buf[BUFSIZ];           /* buffer space to hold SIOCGIFCONFIG option*/     char message[50];             /* buffer for broadcast message */     int   recvNum;                /* number of bytes received */      struct ifconf ifc;                struct ifreq  *ifr;      /* open UDP socket */     sockFd = socket (AF_INET, SOCK_DGRAM, 0);     if (sockFd == ERROR)    	{  	perror ("socket not opened \n"); 	return (ERROR); 	}      /* Demonstrates the usage of SIOCGIFCONF ioctl option.       * This SIOCGIFCONF ioctl option is not really needed for broadcasting.        *      * Following code segment demonstrates the use of SIOCGIFCONF ioctl option.      * Here SIOCGIFCONF option is used to obtain the name of the network      * interface. This code segment is not required for receiving broadcasting       * message.      */      ifc.ifc_len = sizeof (buf);      ifc.ifc_buf = buf;     if (ioctl (sockFd, SIOCGIFCONF, (char *)&ifc) == ERROR)  	{ 	perror ("broadcast: ioctl (get interface configuration)");      	return (ERROR);         }      ifr = ifc.ifc_req;     /* Print the name of the underlying network interface using SIOCGIFCONF      * ioctl option.      */     printf ("SIOCGIFCONF: This socket uses the network interface %s\n\n",               ifr->ifr_name);                /* Zero out and  fill in sockaddr_in structure to receive from*/     bzero ((char *) &sockAddr, sizeof (struct sockaddr_in));     sockAddr.sin_family = AF_INET;     sockAddr.sin_port = htons (port);     sockAddr.sin_addr.s_addr = INADDR_ANY;       /* bind to the socket */      if (bind (sockFd, (struct sockaddr *)& sockAddr, sizeof (sockAddr)) == ERROR) 	{ 	perror ("bind failed"); 	return (ERROR); 	}      FOREVER         /* receive the broadcast message */         if ((recvNum = recv (sockFd, message, sizeof (message), 0)) == ERROR)             {             perror("recv broadcast failed ");             break; 	    }         else             printf ("received %d bytes of broadcast message:  %s\n", recvNum, message);     close (sockFd);     }