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
49 err_status_t
key_limit_set(key_limit_t key,const xtd_seq_num_t s)50 key_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
63 err_status_t
key_limit_clone(key_limit_t original,key_limit_t * new_key)64 key_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
71 err_status_t
key_limit_check(const key_limit_t key)72 key_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
78 key_event_t
key_limit_update(key_limit_t key)79 key_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