#pragma	module	tcpip$udp6_client_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 client 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_CLIENT_SOCK.C
 *      $ link TCPIP$UDP6_CLIENT_SOCK, TCPIP$LIBRARY:TCPIP$LIB/library
 *
 *
 * CONFIGURATION INSTRUCTIONS:
 *
 *    No special configuration required.
 *
 *    
 * RUN INSTRUCTIONS:
 *
 *    To run this example program:
 *
 *    1) Start the client's server program as shown below:
 *
 *	 $ run tcpip$udp6_server_sock
 *	 Waiting for a client datagram on port: m
 *
 *    2) After the server program blocks, start this 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 client program then displays server address information
 *	 and server data as show below:
 *
 *	 Sent a datagram to host: x, port: n
 *	 Data sent: 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	BUFSZ		1024		/* user input buffer size	    */
#define	SERV_PORTNUM	"12345"		/* server port number string	    */


/*
 * FORWARD REFERENCES:
 */

int  main( void );			/* client main			    */
void get_serv_addr( struct addrinfo *hints, struct addrinfo **res );
					/* get server host address	    */

	/* Client Main */

/*
 * FUNCTIONAL DESCRIPTION:
 *
 *    This is the client's main-line code. It handles all the tasks of the
 *    client including: socket creation, writing server data, and deleting
 *    the socket.
 *
 *    This example program implements a typical UDP IPv4/IPv6 client using  
 *    the BSD socket API to handle network i/o operations as shown below:
 *
 *	1) To create a socket:
 *
 *	   socket()
 *
 *	2) To transfer data:
 *
 *	   sendto()
 *
 *	3) 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 )
{
    int sockfd;				/* udp socket descriptor	    */

    char buf[] = "Hello, world!";	/* client data buffer		    */

    struct addrinfo hints;              /* input values to direct operation */
    struct addrinfo *res;               /* linked list of addrinfo structs  */

    /*
     * init server's addrinfo structure
     */

    memset( &hints, 0, sizeof(hints) );
    hints.ai_family = AF_INET6;
    hints.ai_flags = AI_ADDRCONFIG | AI_V4MAPPED | AI_CANONNAME;
    hints.ai_protocol = IPPROTO_TCP;
    hints.ai_socktype = SOCK_STREAM;

    get_serv_addr( &hints, &res );

    /*
     * create udp socket
     */

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

    /*
     * write datagram to server
     */

    if ( sendto(sockfd, buf, sizeof(buf), 0, 
		res->ai_addr, res->ai_addrlen) < 0 )
	{
	perror( "Failed to write datagram to server" );
	exit( EXIT_FAILURE );
	}

    printf( "Sent a datagram to host: %s, port: %d\n",
	    res->ai_canonname, 
	    htons(((struct sockaddr_in6 *)res->ai_addr)->sin6_port)
	  );
    printf( "Data sent: %s\n", buf );	    /* output data buffer	    */

    /*
     * close udp socket
     */

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

    exit( EXIT_SUCCESS );
}

	/* Get Server Host Address */

/*
 * FUNCTIONAL DESCRIPTION:
 *
 *    This function gets the server host's name or address from  the  user 
 *    and then stores it in the addrinfo structure.
 *
 *    Enter "ctrl/z" to terminate program execution.
 *
 * SYNOPSIS:
 *
 *    void get_serv_addr( struct addrinfo *hints, struct addrinfo **res )
 *
 * FORMAL PARAMETERS:
 *
 *    hints  -  pointer to structure containing input values that  may
 *		direct the  operation  by  providing  options  and  by
 *		limiting the returned information to a specific socket
 *              type, address family and/or protocol
 *
 *    res    -  upon successful return of getaddrinfo,  the pointer to
 *		a location for the linked list of addrinfo structures
 *
 * IMPLICIT INPUTS:
 *
 *    ** None **
 *
 * IMPLICIT OUTPUTS:
 *
 *    ** None **
 *
 * FUNCTION VALUE:
 *
 *    ** None **
 *
 * SIDE EFFECTS:
 *
 *    Program execution is terminated if unable to read user's input.
 *
 */ 

void
get_serv_addr( struct addrinfo *hints, struct addrinfo **res )
{
    int gai_error;                      /* return value of getaddrinfo()  */
    char buf[BUFSZ];                    /* input data buffer              */
    const char *port = SERV_PORTNUM;    /* server port number             */

    while ( TRUE )
        {
        printf( "Enter remote host: " );

        if ( fgets(buf, sizeof(buf), stdin) == NULL )
            {
            printf( "Failed to read User input\n" );
            exit( EXIT_FAILURE );
            }

        buf[strlen(buf)-1] = 0;

        gai_error = getaddrinfo( buf, port, hints, res );
        if ( gai_error )
            printf( "Failed to resolve name or address: %s\n",
		    gai_strerror(gai_error)
		  );
        else
            break;
        }
}