1/*
2 * key.c
3 *
4 * key usage limits enforcement
5 *
6 * David A. Mcgrew
7 * Cisco Systems, Inc.
8 */
9/*
10 *
11 * Copyright (c) 2001-2006 Cisco Systems, Inc.
12 * All rights reserved.
13 *
14 * Redistribution and use in source and binary forms, with or without
15 * modification, are permitted provided that the following conditions
16 * are met:
17 *
18 *   Redistributions of source code must retain the above copyright
19 *   notice, this list of conditions and the following disclaimer.
20 *
21 *   Redistributions in binary form must reproduce the above
22 *   copyright notice, this list of conditions and the following
23 *   disclaimer in the documentation and/or other materials provided
24 *   with the distribution.
25 *
26 *   Neither the name of the Cisco Systems, Inc. nor the names of its
27 *   contributors may be used to endorse or promote products derived
28 *   from this software without specific prior written permission.
29 *
30 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
31 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
32 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
33 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
34 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
35 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
36 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
37 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
38 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
39 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
40 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
41 * OF THE POSSIBILITY OF SUCH DAMAGE.
42 *
43 */
44
45#include "key.h"
46
47#define soft_limit 0x10000
48
49err_status_t
50key_limit_set(key_limit_t key, const xtd_seq_num_t s) {
51#ifdef NO_64BIT_MATH
52  if (high32(s) == 0 && low32(s) < soft_limit)
53    return err_status_bad_param;
54#else
55  if (s < soft_limit)
56    return err_status_bad_param;
57#endif
58  key->num_left = s;
59  key->state = key_state_normal;
60  return err_status_ok;
61}
62
63err_status_t
64key_limit_clone(key_limit_t original, key_limit_t *new_key) {
65  if (original == NULL)
66    return err_status_bad_param;
67  *new_key = original;
68  return err_status_ok;
69}
70
71err_status_t
72key_limit_check(const key_limit_t key) {
73  if (key->state == key_state_expired)
74    return err_status_key_expired;
75  return err_status_ok;
76}
77
78key_event_t
79key_limit_update(key_limit_t key) {
80#ifdef NO_64BIT_MATH
81  if (low32(key->num_left) == 0)
82  {
83	  // carry
84	  key->num_left = make64(high32(key->num_left)-1,low32(key->num_left) - 1);
85  }
86  else
87  {
88	  // no carry
89	  key->num_left = make64(high32(key->num_left),low32(key->num_left) - 1);
90  }
91  if (high32(key->num_left) != 0 || low32(key->num_left) >= soft_limit) {
92    return key_event_normal;   /* we're above the soft limit */
93  }
94#else
95  key->num_left--;
96  if (key->num_left >= soft_limit) {
97    return key_event_normal;   /* we're above the soft limit */
98  }
99#endif
100  if (key->state == key_state_normal) {
101    /* we just passed the soft limit, so change the state */
102    key->state = key_state_past_soft_limit;
103  }
104#ifdef NO_64BIT_MATH
105  if (low32(key->num_left) == 0 && high32(key->num_left == 0))
106#else
107  if (key->num_left < 1)
108#endif
109  { /* we just hit the hard limit */
110    key->state = key_state_expired;
111    return key_event_hard_limit;
112  }
113   return key_event_soft_limit;
114}
115
116