keysize_descriptor.c

   1 /* keysize_descriptor.c */
   2 /*
   3     This file is part of the AVR-Crypto-Lib.
   4     Copyright (C) 2006-2015 Daniel Otte (bg@nerilex.org)
   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   bg@nerilex.org
  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         }
  38         if (type == KS_TYPE_LIST) {
  39                 uint8_t items;
  40                 uint16_t item;
  41                 items = pgm_read_byte(ks_desc++);
  42                 while (items--) {
  43                         item = pgm_read_word(ks_desc);
  44                         ks_desc = (uint8_t*)ks_desc + 2;
  45                         if (item == keysize) {
  46                                 return 1;
  47                         }
  48                 }
  49                 ks_desc = (uint8_t*)ks_desc - 2;
  50         }
  51         if (type == KS_TYPE_RANGE) {
  52                 uint16_t max, min;
  53                 min = pgm_read_word(ks_desc);
  54                 ks_desc = (uint8_t*)ks_desc + 2;
  55                 max = pgm_read_word(ks_desc);
  56                 if (min <= keysize && keysize <= max) {
  57                         return 1;
  58                 }
  59         }
  60         if (type == KS_TYPE_ARG_RANGE) {
  61                 uint16_t max, min, dist, offset;
  62                 min = pgm_read_word(ks_desc);
  63                 ks_desc = (uint8_t*)ks_desc + 2;
  64                 max = pgm_read_word(ks_desc);
  65                 ks_desc = (uint8_t*)ks_desc + 2;
  66                 dist = pgm_read_word(ks_desc);
  67                 ks_desc = (uint8_t*)ks_desc + 2;
  68                 offset = pgm_read_word(ks_desc);
  69                 if (min <= keysize && keysize <= max && (keysize % dist == offset)) {
  70                         return 1;
  71                 }
  72         }
  73         if (type > KS_TYPE_ARG_RANGE) {
  74                 /* bad error, you may insert a big warning message here */
  75                 return 0;
  76         }
  77         return is_valid_keysize_P((uint8_t*)ks_desc + 1, keysize); /* search the next record */
  78 }
  79
  80 uint16_t get_keysize(PGM_VOID_P ks_desc){
  81         uint8_t type;
  82         uint16_t keysize;
  83         type = pgm_read_byte(ks_desc);
  84         if(type==KS_TYPE_LIST){
  85                 ks_desc = (uint8_t*)ks_desc + 1;
  86         }
  87         ks_desc = (uint8_t*)ks_desc + 1;
  88         keysize = pgm_read_word(ks_desc);
  89         return keysize;
  90 }
  91
  92 uint16_t get_keysizes(PGM_VOID_P ks_desc, uint16_t** list){
  93         uint8_t type;
  94         uint16_t items;
  95         uint8_t i;
  96         type = pgm_read_byte(ks_desc);
  97         ks_desc = (uint8_t*)ks_desc + 1;
  98         if(type==KS_TYPE_LIST){
  99                 items = pgm_read_byte(ks_desc);
 100                 ks_desc = (uint8_t*)ks_desc + 1;
 101                 if(!*list){
 102                         *list = malloc(items*2);
 103                         if(!*list){
 104                                 return 0;
 105                         }
 106                 }
 107                 for(i=0; i<items; ++i){
 108                         ((uint16_t*)(*list))[i] = pgm_read_word(ks_desc);
 109                         ks_desc = (uint8_t*)ks_desc + 2;
 110                 }
 111                 return items;
 112         }
 113         if(type==KS_TYPE_ARG_RANGE){
 114                 uint16_t min, max, distance, offset;
 115                 min = pgm_read_word(ks_desc);
 116                 ks_desc = (uint8_t*)ks_desc + 2;
 117                 max = pgm_read_word(ks_desc);
 118                 ks_desc = (uint8_t*)ks_desc + 2;
 119                 distance = pgm_read_word(ks_desc);
 120                 ks_desc = (uint8_t*)ks_desc + 2;
 121                 offset = pgm_read_word(ks_desc);
 122                 ks_desc = (uint8_t*)ks_desc + 2;
 123                 items = (max-min)/distance+1;
 124                 if(min%distance!=offset){
 125                         --items;
 126                         min += (distance-(min%distance-offset))%distance;
 127                 }
 128                 if(!*list){
 129                         *list = malloc(items*2);
 130                         if(!*list){
 131                                 return 0;
 132                         }
 133                 }
 134                 i=0;
 135                 while(min<=max){
 136                         ((uint16_t*)*list)[i++] = min;
 137                         min += distance;
 138                 }
 139                 return i;
 140         }
 141         if(type==KS_TYPE_RANGE){
 142                 uint16_t min, max, distance=8, offset=0;
 143                 min = pgm_read_word(ks_desc);
 144                 ks_desc = (uint8_t*)ks_desc + 2;
 145                 max = pgm_read_word(ks_desc);
 146                 items = (max-min)/distance+1;
 147                 if(min%distance!=offset){
 148                         --items;
 149                         min += (distance-(min%distance-offset))%distance;
 150                 }
 151                 if(!*list){
 152                         *list = malloc(items*2);
 153                         if(!*list){
 154                                 return 0;
 155                         }
 156                 }
 157                 i=0;
 158                 while(min<=max){
 159                         ((uint16_t*)*list)[i++] = min;
 160                         min += distance;
 161                 }
 162                 return i;
 163         }
 164         return 0;
 165 }