| /* |
| * key.c |
| * |
| * key usage limits enforcement |
| * |
| * David A. Mcgrew |
| * Cisco Systems, Inc. |
| */ |
| /* |
| * |
| * Copyright (c) 2001-2006 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_err_status_t srtp_key_limit_check (const srtp_key_limit_t key) |
| { |
| if (key->state == srtp_key_state_expired) { |
| return srtp_err_status_key_expired; |
| } |
| 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; |
| } |
| |