michael@0: /*
michael@0:  * key.c
michael@0:  *
michael@0:  * key usage limits enforcement
michael@0:  * 
michael@0:  * David A. Mcgrew
michael@0:  * Cisco Systems, Inc.
michael@0:  */
michael@0: /*
michael@0:  *	
michael@0:  * Copyright (c) 2001-2006 Cisco Systems, Inc.
michael@0:  * All rights reserved.
michael@0:  * 
michael@0:  * Redistribution and use in source and binary forms, with or without
michael@0:  * modification, are permitted provided that the following conditions
michael@0:  * are met:
michael@0:  * 
michael@0:  *   Redistributions of source code must retain the above copyright
michael@0:  *   notice, this list of conditions and the following disclaimer.
michael@0:  * 
michael@0:  *   Redistributions in binary form must reproduce the above
michael@0:  *   copyright notice, this list of conditions and the following
michael@0:  *   disclaimer in the documentation and/or other materials provided
michael@0:  *   with the distribution.
michael@0:  * 
michael@0:  *   Neither the name of the Cisco Systems, Inc. nor the names of its
michael@0:  *   contributors may be used to endorse or promote products derived
michael@0:  *   from this software without specific prior written permission.
michael@0:  * 
michael@0:  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
michael@0:  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
michael@0:  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
michael@0:  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
michael@0:  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
michael@0:  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
michael@0:  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
michael@0:  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
michael@0:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
michael@0:  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
michael@0:  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
michael@0:  * OF THE POSSIBILITY OF SUCH DAMAGE.
michael@0:  *
michael@0:  */
michael@0: 
michael@0: #include "key.h"
michael@0: 
michael@0: #define soft_limit 0x10000
michael@0: 
michael@0: err_status_t
michael@0: key_limit_set(key_limit_t key, const xtd_seq_num_t s) {
michael@0: #ifdef NO_64BIT_MATH
michael@0:   if (high32(s) == 0 && low32(s) < soft_limit)
michael@0:     return err_status_bad_param;
michael@0: #else
michael@0:   if (s < soft_limit)
michael@0:     return err_status_bad_param;
michael@0: #endif
michael@0:   key->num_left = s;
michael@0:   key->state = key_state_normal;
michael@0:   return err_status_ok;
michael@0: }
michael@0: 
michael@0: err_status_t
michael@0: key_limit_clone(key_limit_t original, key_limit_t *new_key) {
michael@0:   if (original == NULL)
michael@0:     return err_status_bad_param;
michael@0:   *new_key = original;
michael@0:   return err_status_ok;
michael@0: }
michael@0: 
michael@0: err_status_t
michael@0: key_limit_check(const key_limit_t key) {
michael@0:   if (key->state == key_state_expired)
michael@0:     return err_status_key_expired;
michael@0:   return err_status_ok;
michael@0: }
michael@0: 
michael@0: key_event_t
michael@0: key_limit_update(key_limit_t key) {
michael@0: #ifdef NO_64BIT_MATH
michael@0:   if (low32(key->num_left) == 0)
michael@0:   {
michael@0: 	  // carry
michael@0: 	  key->num_left = make64(high32(key->num_left)-1,low32(key->num_left) - 1);
michael@0:   }
michael@0:   else
michael@0:   {
michael@0: 	  // no carry
michael@0: 	  key->num_left = make64(high32(key->num_left),low32(key->num_left) - 1);
michael@0:   }
michael@0:   if (high32(key->num_left) != 0 || low32(key->num_left) >= soft_limit) {
michael@0:     return key_event_normal;   /* we're above the soft limit */
michael@0:   }
michael@0: #else
michael@0:   key->num_left--;
michael@0:   if (key->num_left >= soft_limit) {
michael@0:     return key_event_normal;   /* we're above the soft limit */
michael@0:   }
michael@0: #endif
michael@0:   if (key->state == key_state_normal) {
michael@0:     /* we just passed the soft limit, so change the state */
michael@0:     key->state = key_state_past_soft_limit;
michael@0:   }
michael@0: #ifdef NO_64BIT_MATH
michael@0:   if (low32(key->num_left) == 0 && high32(key->num_left == 0))
michael@0: #else
michael@0:   if (key->num_left < 1)
michael@0: #endif
michael@0:   { /* we just hit the hard limit */
michael@0:     key->state = key_state_expired;
michael@0:     return key_event_hard_limit;
michael@0:   }
michael@0:    return key_event_soft_limit;
michael@0: }
michael@0: