`connect_to_server()`

This offers a basic, no-frills function that creates a TCP connection.

Example A-7 connect_to_server()

/*
 * Function: connect_to_server
 *
 * Purpose: Opens a TCP connection to the name host and port.
 *
 * Arguments:
 *
 *      host            (r) the target host name
 *      port            (r) the target port, in host byte order
 *
 * Returns: the established socket file desciptor, or -1 on failure
 *
 * Effects:
 *
 * The host name is resolved with gethostbyname(), and the socket is
 * opened and connected.  If an error occurs, an error message is
 * displayed and -1 is returned.
 */
int connect_to_server(host, port)
     char *host;
     u_short port;
{
     struct sockaddr_in saddr;
     struct hostent *hp;
     int s;
    
     if ((hp = gethostbyname(host)) == NULL) {
          fprintf(stderr, "Unknown host: %s\n", host);
          return -1;
     }

     saddr.sin_family = hp->h_addrtype;
     memcpy((char *)&saddr.sin_addr, hp->h_addr, sizeof(saddr.sin_addr));
     saddr.sin_port = htons(port);

     if ((s = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
          perror("creating socket");
          return -1;
     }
     if (connect(s, (struct sockaddr *)&saddr, sizeof(saddr)) < 0) {
          perror("connecting to server");
          (void) close(s);
          return -1;
     }

     return s;
}

Server-Side Application

This is the application that receives messages from the client function described earlier.

Program Headers

These are the declarations for the server program, plus a function that explains the syntax if an incorrect command line is given. Here the security mechanism is set to be the GSS-API-provided default.

Example A-8 Program Headers

/*
 * Copyright 1994 by OpenVision Technologies, Inc.
 *
 * Permission to use, copy, modify, distribute, and sell this software
 * and its documentation for any purpose is hereby granted without fee,
 * provided that the above copyright notice appears in all copies and
 * that both that copyright notice and this permission notice appear in
 * supporting documentation, and that the name of OpenVision not be used
 * in advertising or publicity pertaining to distribution of the software
 * without specific, written prior permission. OpenVision makes no
 * representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied warranty.
 *
 * OPENVISION DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
 * EVENT SHALL OPENVISION BE LIABLE FOR ANY SPECIAL, INDIRECT OR
 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
 * USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
 * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 * PERFORMANCE OF THIS SOFTWARE.
 */

#if !defined(lint) && !defined(__CODECENTER__)
static char *rcsid = "$Header: /afs/athena.mit.edu/astaff/project/krbdev/.cvsroot
/src/appl/gss-sample/gss-server.c,v 1.17 1996/10/22 00:07:59 tytso Exp $";
#endif

#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <netinet/in.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <stdlib.h>
#include <ctype.h>

#include <gssapi/gssapi.h>
#include <gssapi/gssapi_ext.h>
#include "gss-misc.h"

#ifdef USE_STRING_H
#include <string.h>
#else
#include <strings.h>
#endif

/* global mechanism oid used in acquire cred and display status */
gss_OID g_mechOid = GSS_C_NULL_OID;

void usage()
{
     fprintf(stderr, "Usage: gss-server [-port port] [-verbose]\n");
     fprintf(stderr, "       [-inetd] [-logfile file]");
     fprintf(stderr, " [-mech mechoid] [service_name]\n");
     exit(1);
}

FILE *log;

int verbose = 0;


A. Sample C-Based GSS-API Programs Client-Side Application `client_establish_context()`