/*
*******************************************************************************
** FILE: UDP_socket_server.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.
**
**
**
** SERVER SEQUENCE OF OPERATIONS:
**    1. Create a socket:            socket()
**    2. Bind the socket to address  bind()	
**    3. Exchange data:              recvfrom(), sendto()
**    4. Close the socket:           close() 
**
**
** BUILDING EXECUTABLES:
**
** 1. on VAX : 
**	with VAXC:
**	       $ CC UDP_SOCKET_SERVER.C
**             $ LINK UDP_SOCKET_SERVER, 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_SERVER.C /DEFINE=TCPWARE
**             $ LINK UDP_SOCKET_SERVER, SYS$INPUT/OPTIONS
**                              SYS$SHARE:TCPWARE_SOCKLIB_SHR/SHARE
**                              SYS$SHARE:VAXCRTL/SHARE
**	with DECC:
**	       $ CC/DECC/PREFIX_LIBRARY_ENTRIES=ALL UDP_SOCKET_SERVER.C
**	       $ LINK UDDRIVER_SERVER
**
** 2. on ALPHA: $ CC/DECC/PREFIX_LIBRARY_ENTRIES=ALL UDP_SOCKET_SERVER.C
**              $ LINK UDP_SOCKET_SERVER
**
*******************************************************************************
** 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>
#include <inet.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	                status;			/* For return status */
    int	                continue_IO;		/* boolean continue status */
    int			listen_socket;
    int                 addrlen;
    char                server_name[200];
    char                buffer[1024];
    struct hostent      *hostent_P;	/* internet host address structure */
    struct servent      *servent_P;	/* service port structure */
    struct sockaddr_in  server_adr;	/* server socket address structure */
    struct sockaddr_in  client_adr;	/* client socket address structure */



    /*
    ** Setup server family and internet address.
    ** INADDR_ANY specifies accepting connects to any local IP address
    ** for this node.
    */
    memset( &server_adr, 0, sizeof( server_adr) );
    server_adr.sin_family = AF_INET;
    server_adr.sin_addr.s_addr = INADDR_ANY;


    /* 
    ** 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));


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


    /* Bind listening socket to server address */
    addrlen = sizeof( server_adr);
    if ( bind( listen_socket, (struct sockaddr *)&server_adr, addrlen) < 0)
    {
	perror( "bind");
	exit(1);
    } 


    /*
    ** Keep receiving messages, till "CLOSE" is input.
    */
    for (continue_IO = TRUE; continue_IO; )
    {
	status = recvfrom( listen_socket, buffer, sizeof(buffer), 0,
		    (struct sockaddr *)&client_adr, &addrlen);
	if ( status < 0)
	{
	    perror( "Error reading message.");
	    continue;
	} 


	/*
	** Use remote IP address to query DNS for host name.
	** If unknown, just show remote IP address.
	*/
	hostent_P = gethostbyaddr( (char *) &client_adr.sin_addr,4, AF_INET);
	if (hostent_P)
	    printf("\nClient data received from %s = %s\n",
		inet_ntoa( client_adr.sin_addr), hostent_P->h_name);
	else
	    printf("\nClient data received from [%s]\n",
		inet_ntoa( client_adr.sin_addr) );


	buffer[ status] = '\0';		    /* terminate received string */
	printf("Received: %s\n", buffer);   /* display the message received */


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


    /* 
    ** Close the listening socket.
    */
    status = close( listen_socket);
}