/*
*******************************************************************************
** FILE: UDP_socket_client.C -- example program demonstrating usage of
**       network programming library using UNIX-like connectionless UDP sockets.
**
** PRODUCT: TCPware for VMS
**
** VERSION: V5.6
**
** Copyright (c) 2001, 2002 by
** Process Software LLC
** Framingham, Massachusetts
**
** Copyright (c) 1997-1999 by
** Process Software Corporation
** Framingham, Massachusetts
**
** This software is furnished under a  license  for  use  on  a
** single  computer  system  and  may  be  copied only with the
** inclusion of the above copyright notice.  This  software, or
** any  other  copies thereof, may not be provided or otherwise
** made available to any other person except for  use  on  such
** system  and to one who agrees to these license terms.  Title
** to and ownership of the software shall at all  times  remain
** in Process Software LLC's name.
**
** The information  in  this  document  is  subject  to  change
** without  notice  and should not be construed as a commitment
** by  Process Software LLC.   Process Software LLC assumes  no
** responsibility for any errors that may appear in this document.
**
**
** ABSTRACT:
**
** UDP_socket_server.c and UDP_socket_client.c are a pair of example programs
** illustrating the use of datagrams via UNIX-like connectionless UDP sockets.
**
**
**
** CLIENT SEQUENCE OF OPERATIONS:
**    1. Create a socket:            socket()
**    2. Exchange data:              recvfrom(), sendto()
**    3. Close the socket:           close() 
**
**
** BUILDING EXECUTABLES:
**
** 1. on VAX : 
**	with VAXC:
**	       $ CC UDP_SOCKET_CLIENT.C
**             $ LINK UDP_SOCKET_CLIENT, TCPWARE:UCX$IPC/LIB, -
**				SYS$INPUT/OPTIONS
**                              SYS$SHARE:VAXCRTL/SHARE
**
** Instead of UCX's BG devices, TCpware's socket library can be used.
** ("/DEFINE=TCPWARE" allows close() to be redefined to a socket function.) :
**
**	       $ CC UDP_SOCKET_CLIENT.C /DEFINE=TCPWARE
**             $ LINK UDP_SOCKET_CLIENT, SYS$INPUT/OPTIONS
**                              SYS$SHARE:TCPWARE_SOCKLIB_SHR/SHARE
**                              SYS$SHARE:VAXCRTL/SHARE
**	with DECC:
**	       $ CC/DECC/PREFIX_LIBRARY_ENTRIES=ALL UDP_SOCKET_CLIENT.C
**	       $ LINK UDDRIVER_CLIENT
**
** 2. on ALPHA: $ CC/DECC/PREFIX_LIBRARY_ENTRIES=ALL UDP_SOCKET_CLIENT.C
**              $ LINK UDP_SOCKET_CLIENT
**
*******************************************************************************
** REQUEST: If you have comments, please send them to "support@process.com"
*******************************************************************************
*/


#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <types.h>
#include <unixio.h>
#include <socket.h>
#include <netdb.h>
#include <in.h>


#define SERVER_PORT 65000  /* if getservbyname fails, use this port number */
#define SERVICE  "test_discard"
#define PROTO    "udp"


#ifdef VAXC

#ifdef TCPWARE
#   define close	socket_close
#endif /* TCPWARE */

/* function prototypes */
int socket_close( int s);
#endif /* VAXC */


main()
{
    int			  client_socket;
    int			  addrlen;
    int	                  status;		/* For return status */
    int	                  continue_IO;		/* boolean continue flag */
    int                   got_host;
    char                  server_name[200];
    int                   buflen;
    char                  buffer[1024];
    struct servent        *servent_P;
    struct hostent        *hostent_P;
    struct sockaddr_in    server_adr;



    /* 
    ** Get server port number for named service.
    ** If unknown ( == 0 or = -1), use default define.
    */
    memset( &server_adr, 0, sizeof( server_adr) );
    if ( (int)(servent_P = getservbyname( SERVICE, PROTO)) > 0)
	server_adr.sin_port = servent_P->s_port;
    else
	server_adr.sin_port = htons(SERVER_PORT);

    printf("Will receive on server port #: %d\n\n", ntohs(server_adr.sin_port));


    /* Query user for server name and get corresponding internet address. */
    for (got_host = FALSE; got_host == FALSE; )
    {
	printf("Enter name of remote host: ");
	gets( server_name);
	if ((hostent_P = gethostbyname(server_name)) == NULL)
	{
	    printf("Error, gethostbyname failed\n");
	}
	else
	{
	    got_host = TRUE;

	    server_adr.sin_family = hostent_P->h_addrtype;
	    server_adr.sin_addr = *( (struct in_addr *)(hostent_P->h_addr) );
	}
    }


    /* Create socket */
    if ( ( client_socket = socket( AF_INET, SOCK_DGRAM, 0) ) < 0)
    {
	perror( "client_socket");
	exit(1);
    }


    /*
    ** Keep getting input string & send to the server, till "CLOSE" is input.
    */
    printf("\n\nKeep getting keyboard input & sending to the server,\n till ^Z (client exit) or 'CLOSE' (server exit) is input.\n\n");
    for (continue_IO = TRUE; continue_IO; )
    {
	/*
	** Prepare message to send:
	**	Setup message (Replace with your application function.)
	*/
	printf("\nInput string to send. <CR> sends default: \n");
	if ( gets( buffer) == NULL)
	    break;

	buflen = strlen(buffer);

	/* if no input, setup default message */
	if ( 0 == buflen)
	{
	    strcpy( buffer, "User Datagram Protocol is described in RFC 768");
	    buflen = strlen(buffer);
	}

	/* 
	** Send the message 
	*/
        addrlen = sizeof( server_adr);
	status = sendto( client_socket, buffer, buflen, 0,
			(struct sockaddr *)&server_adr, addrlen);
	if ( status < 0 )
	{
	    perror("Error sending message.");
	    break;
	}


	if ( 0 == strcmp( buffer, "CLOSE") || 0 == strcmp( buffer, "close") )
	    continue_IO = FALSE;
    }

    /* Close the socket */
    close( client_socket);
}