generate_seq_number.c revision 178825 
1/*
2 * Copyright (c) 1997 - 2001 Kungliga Tekniska H�gskolan
3 * (Royal Institute of Technology, Stockholm, Sweden).
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 *
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 *
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * 3. Neither the name of the Institute nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#include <krb5_locl.h>
35
36RCSID("$Id: generate_seq_number.c 17442 2006-05-05 09:31:15Z lha $");
37
38krb5_error_code KRB5_LIB_FUNCTION
39krb5_generate_seq_number(krb5_context context,
40			 const krb5_keyblock *key,
41			 uint32_t *seqno)
42{
43    krb5_error_code ret;
44    krb5_keyblock *subkey;
45    uint32_t q;
46    u_char *p;
47    int i;
48
49    ret = krb5_generate_subkey (context, key, &subkey);
50    if (ret)
51	return ret;
52
53    q = 0;
54    for (p = (u_char *)subkey->keyvalue.data, i = 0;
55	 i < subkey->keyvalue.length;
56	 ++i, ++p)
57	q = (q << 8) | *p;
58    q &= 0xffffffff;
59    *seqno = q;
60    krb5_free_keyblock (context, subkey);
61    return 0;
62}
63