#pragma	module	tcpip$udp6_server_sock			\
		"V5.4-00"

/*
 * © Copyright 1976, 2003 Hewlett-Packard Development Company, L.P.
 *
 * Confidential computer software.  Valid license  from  HP  and/or its
 * subsidiaries required for possession, use, or copying.
 *
 * Consistent with FAR 12.211 and 12.212, Commercial Computer Software,
 * Computer Software Documentation,  and  Technical Data for Commercial
 * Items  are  licensed to the U.S. Government under vendor's  standard
 * commercial license.
 *
 * Neither HP nor any of its subsidiaries shall be liable for technical
 * or editorial errors or omissions contained herein.   The information
 * in  this document is provided  "as is"  without warranty of any kind
 * and is subject  to  change  without  notice.   The warranties for HP
 * products are set forth in the express  limited  warranty  statements
 * accompanying such products.   Nothing herein should be construed  as
 * constituting an additional warranty.
 *
 * ++
 * FACILITY:
 *
 *    EXAMPLES
 *      
 * ABSTRACT:
 *
 *    This is an example of a UDP/IP IPv4/IPv6 server using 4.x 
 *    BSD  socket  Application Programming Interface  (API)  to
 *    handle network I/O operations.
 *
 *    Refer to 'Build, Configuration, and Run Instructions' for
 *    details on how to build, configure, and run this program.
 *
 * ENVIRONMENT:
 *
 *    OpenVMS Alpha/VAX V7.2-2
 *    TCP/IP Services V5.4 or higher
 *
 * AUTHOR:
 *
 *    TCPIP Development Group,  CREATION DATE: 10-Jan-2003
 *
 * --
 */

	/* Build, Configuration, and Run Instructions */

/*
 * BUILD INSTRUCTIONS:
 *
 *    To build this example program use commands of the form,
 *
 *    using the "C" compiler:
 *
 *      $ cc/define=(_SOCKADDR_LEN)/include=TCPIP$EXAMPLES: -
 *        TCPIP$UDP6_SERVER_SOCK.C
 *      $ link TCPIP$UDP6_SERVER_SOCK, TCPIP$LIBRARY:TCPIP$LIB/library
 *
 *
 * CONFIGURATION INSTRUCTIONS:
 *
 *    No special configuration required.
 *
 *    
 * RUN INSTRUCTIONS:
 *
 *    To run this example program:
 *
 *    1) Start this server program server as shown below:
 *
 *	 $ run tcpip$udp6_server_sock
 *	 Waiting for a client datagram on port: m
 *
 *    2) After the server program blocks, start the client program,
 *       entering the server host as shown below:
 *
 *	 $ run tcpip$udp6_client_sock
 *	 Enter remote host:
 *
 *       Note: You can specify a server host using any
 *             of the following:
 *
 *             o An IPv4 address in dotted-decimal notation
 *               (e.g. 16.20.10.56)
 *
 *             o An IPv6 address in hexadecimal
 *               (e.g. 1070:0:0:0:0:800:200C:417B)
 *
 *             o An IPv4-mapped IPv6 address in hexadecimal
 *               (e.g. ::ffff:16.20.10.56)
 *
 *             o A host domain name
 *               (e.g. serverhost.hp.com)
 *
 *    3) The server program then displays client address information
 *	 and client data as show below:
 *
 *	 Received a datagram from host: x (a), port: n
 *	 Data received: Hello, world!
 *
 *    You can enter "ctrl/z" at any user prompt to terminate program
 *    execution.
 *
 */


/*
 * INCLUDE FILES:
 */

#include <in.h>			    /* define internet related constants,   */
				    /* functions, and structures	    */
#include <inet.h>		    /* define network address info	    */

#include <netdb.h>		    /* define network database library info */

#include <socket.h>		    /* define BSD 4.x socket api	    */
#include <stdio.h>		    /* define standard i/o functions	    */
#include <stdlib.h>		    /* define standard library functions    */
#include <string.h>		    /* define string handling functions	    */

#include <unixio.h>		    /* define unix i/o			    */


/*
 * NAMED CONSTANTS:
 */

#define	SERV_PORTNUM	12345		/* server port number		    */


/*
 * FORWARD REFERENCES:
 */

int  main( void );			/* server main			    */

	/* Server Main */

/*
 * FUNCTIONAL DESCRIPTION:
 *
 *    This is the server's main-line code. It handles all the tasks of the
 *    server including: socket creation, binding a socket to the  server's
 *    internet address and port, and reading client data.
 *
 *    This example program implements a typical UDP IPv4 server using  the
 *    BSD socket API to handle network i/o operations as shown below:
 *
 *	1) To create a socket:
 *
 *	   socket()
 *
 *	2) To set REUSEADDR socket option:
 *
 *	   setsockopt()
 *
 *	3) To bind internet address and port number to a socket:
 *
 *	   bind()
 *
 *	4) To transfer data:
 *
 *	   recvfrom()
 *
 *	5) To close a socket:
 *
 *	   close()
 *
 *    This function is invoked by the DCL "RUN" command (see below);  the
 *    function's  completion  status is interpreted by DCL and if needed,
 *    an error message is displayed.
 *
 * SYNOPSIS:
 *
 *    int main( void )
 *
 * FORMAL PARAMETERS:
 *
 *    ** None **
 *
 * IMPLICIT INPUTS:
 *
 *    ** None **
 *
 * IMPLICIT OUTPUTS:
 *
 *    ** None **
 *
 * FUNCTION VALUE:
 *
 *    completion status
 *
 * SIDE EFFECTS:
 *
 *    ** None **
 *
 */ 

int
main( void )
{
    char buf[512];			/* server data buffer		    */

    int	optval = 1;			/* SO_REUSEADDR'S option value (on) */

    int sockfd;				/* socket descriptor		    */
    int gni_error;			/* return status for getnameinfo()  */

    unsigned int client_addrlen;	/* returned length of client socket */
					/* address structure		    */
    struct sockaddr_in6 client_addr;    /* client socket address structure  */
    struct sockaddr_in6 serv_addr;      /* server socket address structure  */

    char node[NI_MAXHOST];              /* buffer to receive node name      */
    char port[NI_MAXHOST];              /* buffer to receive port number    */
    char addrbuf[INET6_ADDRSTRLEN];     /* buffer to receive host's address */

    /*
     * init client's socket address structure
     */

    memset( &client_addr, 0, sizeof(client_addr) );

    /*
     * init server's socket address structure
     */

    memset( &serv_addr, 0, sizeof(serv_addr) );
    serv_addr.sin6_family      = AF_INET6;
    serv_addr.sin6_port        = htons( SERV_PORTNUM );
    serv_addr.sin6_addr        = in6addr_any;

    /*
     * create a udp socket
     */

    if ( (sockfd = socket(AF_INET6, SOCK_DGRAM, 0)) < 0 )
	{
	perror( "Failed to create socket" );
	exit( EXIT_FAILURE );
	}

    /*
     * bind server's internet address and port number to socket
     */

    if ( setsockopt(sockfd,
		    SOL_SOCKET, SO_REUSEADDR, &optval, sizeof(optval)) < 0 )
	{
	perror( "Failed to set socket option" );
	exit( EXIT_FAILURE );
	}

    if ( bind(sockfd,
	      (struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0 )
	{
	perror( "Failed to bind socket" );
	exit( EXIT_FAILURE );
	}

    /*
     * read datagram from client
     */

    printf( "Waiting for a client datagram on port: %d\n",
	    ntohs(serv_addr.sin6_port)
	  );

    client_addrlen = sizeof(client_addr);

    if ( recvfrom(sockfd, buf, sizeof(buf), 0,
		  (struct sockaddr *) &client_addr, &client_addrlen) < 0 )
	{
	perror( "Failed to read datagram from client" );
	exit( EXIT_FAILURE );
	}

    gni_error = getnameinfo( (struct sockaddr *)&client_addr, client_addrlen,
                             node, sizeof(node), NULL, 0, NI_NAMEREQD 
			   );
    if ( gni_error )
        {
        printf( "Failed to translate client address: %s\n", 
		gai_strerror(gni_error) 
	      );
        exit( EXIT_FAILURE );
        }

    gni_error = getnameinfo( (struct sockaddr *)&client_addr, client_addrlen,
                             addrbuf, sizeof(addrbuf), port, sizeof(port),
                             NI_NUMERICHOST | NI_NUMERICSERV
			   );
    if ( gni_error )
        {
        printf( "Failed to translate client address and/or port: %s\n", 
		gai_strerror(gni_error) 
	      );
        exit( EXIT_FAILURE );
        }

    printf( "Received a datagram from host: %s (%s), port: %s\n",
	    node, addrbuf, port
	  );
    printf( "Data received: %s\n", buf );  /* output client's data buffer  */

    /*
     * close udp socket
     */

    if ( close(sockfd) < 0 )
	{
	perror( "Failed to close socket" );
	exit( EXIT_FAILURE );
	}

    exit( EXIT_SUCCESS );
}