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/*
* key.c
*
* key usage limits enforcement
*
* David A. Mcgrew
* Cisco Systems, Inc.
*/
/*
*
* Copyright (c) 2001-2017 Cisco Systems, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution.
*
* Neither the name of the Cisco Systems, Inc. nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include "key.h"
#define soft_limit 0x10000
srtp_err_status_t srtp_key_limit_set(srtp_key_limit_t key,
const srtp_xtd_seq_num_t s)
{
#ifdef NO_64BIT_MATH
if (high32(s) == 0 && low32(s) < soft_limit) {
return srtp_err_status_bad_param;
}
#else
if (s < soft_limit) {
return srtp_err_status_bad_param;
}
#endif
key->num_left = s;
key->state = srtp_key_state_normal;
return srtp_err_status_ok;
}
srtp_err_status_t srtp_key_limit_clone(srtp_key_limit_t original,
srtp_key_limit_t *new_key)
{
if (original == NULL) {
return srtp_err_status_bad_param;
}
*new_key = original;
return srtp_err_status_ok;
}
srtp_key_event_t srtp_key_limit_update(srtp_key_limit_t key)
{
#ifdef NO_64BIT_MATH
if (low32(key->num_left) == 0) {
// carry
key->num_left =
make64(high32(key->num_left) - 1, low32(key->num_left) - 1);
} else {
// no carry
key->num_left = make64(high32(key->num_left), low32(key->num_left) - 1);
}
if (high32(key->num_left) != 0 || low32(key->num_left) >= soft_limit) {
return srtp_key_event_normal; /* we're above the soft limit */
}
#else
key->num_left--;
if (key->num_left >= soft_limit) {
return srtp_key_event_normal; /* we're above the soft limit */
}
#endif
if (key->state == srtp_key_state_normal) {
/* we just passed the soft limit, so change the state */
key->state = srtp_key_state_past_soft_limit;
}
#ifdef NO_64BIT_MATH
if (low32(key->num_left) == 0 && high32(key->num_left == 0))
#else
if (key->num_left < 1)
#endif
{ /* we just hit the hard limit */
key->state = srtp_key_state_expired;
return srtp_key_event_hard_limit;
}
return srtp_key_event_soft_limit;
}
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