keysize_descriptor.c

   1 /* keysize_descriptor.c */
   2 /*
   3     This file is part of the AVR-Crypto-Lib.
   4     Copyright (C) 2009  Daniel Otte (daniel.otte@rub.de)
   5
   6     This program is free software: you can redistribute it and/or modify
   7     it under the terms of the GNU General Public License as published by
   8     the Free Software Foundation, either version 3 of the License, or
   9     (at your option) any later version.
  10
  11     This program is distributed in the hope that it will be useful,
  12     but WITHOUT ANY WARRANTY; without even the implied warranty of
  13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14     GNU General Public License for more details.
  15
  16     You should have received a copy of the GNU General Public License
  17     along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18 */
  19 /**
  20  * \file    keysize_descriptor.c
  21  * \author  Daniel Otte
  22  * \email   daniel.otte@rub.de
  23  * \date    2009-01-07
  24  * \license GPLv3 or later
  25  */
  26
  27 #include <stdint.h>
  28 #include <stdlib.h>
  29 #include <avr/pgmspace.h>
  30 #include "keysize_descriptor.h"
  31
  32 uint8_t is_valid_keysize_P(PGM_VOID_P ks_desc, uint16_t keysize){
  33         uint8_t type;
  34         type = pgm_read_byte(ks_desc++);
  35         if(type==KS_TYPE_TERMINATOR)
  36                 return 0;
  37         if(type==KS_TYPE_LIST){
  38                 uint8_t items;
  39                 uint16_t item;
  40                 items = pgm_read_byte(ks_desc++);
  41                 while(items--){
  42                         item = pgm_read_word(ks_desc);
  43                         ks_desc = (uint8_t*)ks_desc + 2;
  44                         if(item==keysize)
  45                                 return 1;
  46                 }
  47                 ks_desc = (uint8_t*)ks_desc - 2;
  48         }
  49         if(type==KS_TYPE_RANGE){
  50                 uint16_t max, min;
  51                 min = pgm_read_word(ks_desc);
  52                 ks_desc = (uint8_t*)ks_desc + 2;
  53                 max = pgm_read_word(ks_desc);
  54                 if(min<=keysize && keysize<=max)
  55                         return 1;
  56         }
  57         if(type==KS_TYPE_ARG_RANGE){
  58                 uint16_t max, min, dist, offset;
  59                 min = pgm_read_word(ks_desc);
  60                 ks_desc = (uint8_t*)ks_desc + 2;
  61                 max = pgm_read_word(ks_desc);
  62                 ks_desc = (uint8_t*)ks_desc + 2;
  63                 dist = pgm_read_word(ks_desc);
  64                 ks_desc = (uint8_t*)ks_desc + 2;
  65                 offset = pgm_read_word(ks_desc);
  66                 if(min<=keysize && keysize<=max && (keysize%dist==offset))
  67                         return 1;
  68         }
  69         if(type>KS_TYPE_ARG_RANGE){
  70                 /* bad error, you may insert a big warning message here */
  71                 return 0;
  72         }
  73         return is_valid_keysize_P((uint8_t*)ks_desc+1, keysize); /* search the next record */
  74 }
  75
  76 uint16_t get_keysize(PGM_VOID_P ks_desc){
  77         uint8_t type;
  78         uint16_t keysize;
  79         type = pgm_read_byte(ks_desc);
  80         if(type==KS_TYPE_LIST){
  81                 ks_desc = (uint8_t*)ks_desc + 1;
  82         }
  83         ks_desc = (uint8_t*)ks_desc + 1;
  84         keysize = pgm_read_word(ks_desc);
  85         return keysize;
  86 }
  87
  88 uint16_t get_keysizes(PGM_VOID_P ks_desc, uint16_t** list){
  89         uint8_t type;
  90         uint16_t items;
  91         uint8_t i;
  92         type = pgm_read_byte(ks_desc);
  93         ks_desc = (uint8_t*)ks_desc + 1;
  94         if(type==KS_TYPE_LIST){
  95                 items = pgm_read_byte(ks_desc);
  96                 ks_desc = (uint8_t*)ks_desc + 1;
  97                 if(!*list){
  98                         *list = malloc(items*2);
  99                         if(!*list){
 100                                 return 0;
 101                         }
 102                 }
 103                 for(i=0; i<items; ++i){
 104                         ((uint16_t*)(*list))[i] = pgm_read_word(ks_desc);
 105                         ks_desc = (uint8_t*)ks_desc + 2;
 106                 }
 107                 return items;
 108         }
 109         if(type==KS_TYPE_ARG_RANGE){
 110                 uint16_t min, max, distance, offset;
 111                 min = pgm_read_word(ks_desc);
 112                 ks_desc = (uint8_t*)ks_desc + 2;
 113                 max = pgm_read_word(ks_desc);
 114                 ks_desc = (uint8_t*)ks_desc + 2;
 115                 distance = pgm_read_word(ks_desc);
 116                 ks_desc = (uint8_t*)ks_desc + 2;
 117                 offset = pgm_read_word(ks_desc);
 118                 ks_desc = (uint8_t*)ks_desc + 2;
 119                 items = (max-min)/distance+1;
 120                 if(min%distance!=offset){
 121                         --items;
 122                         min += (distance-(min%distance-offset))%distance;
 123                 }
 124                 if(!*list){
 125                         *list = malloc(items*2);
 126                         if(!*list){
 127                                 return 0;
 128                         }
 129                 }
 130                 i=0;
 131                 while(min<=max){
 132                         ((uint16_t*)*list)[i++] = min;
 133                         min += distance;
 134                 }
 135                 return i;
 136         }
 137         if(type==KS_TYPE_RANGE){
 138                 uint16_t min, max, distance=8, offset=0;
 139                 min = pgm_read_word(ks_desc);
 140                 ks_desc = (uint8_t*)ks_desc + 2;
 141                 max = pgm_read_word(ks_desc);
 142                 items = (max-min)/distance+1;
 143                 if(min%distance!=offset){
 144                         --items;
 145                         min += (distance-(min%distance-offset))%distance;
 146                 }
 147                 if(!*list){
 148                         *list = malloc(items*2);
 149                         if(!*list){
 150                                 return 0;
 151                         }
 152                 }
 153                 i=0;
 154                 while(min<=max){
 155                         ((uint16_t*)*list)[i++] = min;
 156                         min += distance;
 157                 }
 158                 return i;
 159         }
 160         return 0;
 161 }