proxmark3/common/crc.c
iceman1001 c04ac4f9ac ADD: 'hf felica reader' - added pm3 as FeliCa reader
ADD:  raw commands -  added the basis for sending RAW commands to FeliCa.
CHG: CRC16 rework,  uses table based implementation.  This will change more functions as I go on.
2018-01-29 13:42:02 +01:00

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3.9 KiB
C

//-----------------------------------------------------------------------------
// This code is licensed to you under the terms of the GNU GPL, version 2 or,
// at your option, any later version. See the LICENSE.txt file for the text of
// the license.
//-----------------------------------------------------------------------------
// Generic CRC calculation code.
//-----------------------------------------------------------------------------
// the Check value below in the comments is CRC of the string '123456789'
//
#include "crc.h"
void crc_init_ref(crc_t *crc, int order, uint32_t polynom, uint32_t initial_value, uint32_t final_xor, bool refin, bool refout) {
crc_init(crc, order, polynom, initial_value, final_xor);
crc->refin = refin;
crc->refout = refout;
crc_clear(crc);
}
void crc_init(crc_t *crc, int order, uint32_t polynom, uint32_t initial_value, uint32_t final_xor) {
crc->order = order;
crc->topbit = BITMASK( order-1 );
crc->polynom = polynom;
crc->initial_value = initial_value;
crc->final_xor = final_xor;
crc->mask = (1L<<order)-1;
crc->refin = false;
crc->refout = false;
crc_clear(crc);
}
void crc_clear(crc_t *crc) {
crc->state = crc->initial_value & crc->mask;
if (crc->refin)
crc->state = reflect(crc->state, crc->order);
}
void crc_update2(crc_t *crc, uint32_t data, int data_width){
if (crc->refin)
data = reflect(data, data_width);
// Bring the next byte into the remainder.
crc->state ^= data << (crc->order - data_width);
for( uint8_t bit = data_width; bit > 0; --bit) {
if (crc->state & crc->topbit)
crc->state = (crc->state << 1) ^ crc->polynom;
else
crc->state = (crc->state << 1);
}
}
void crc_update(crc_t *crc, uint32_t data, int data_width)
{
if (crc->refin)
data = reflect(data, data_width);
int i;
for(i=0; i<data_width; i++) {
int oldstate = crc->state;
crc->state = crc->state >> 1;
if( (oldstate^data) & 1 ) {
crc->state ^= crc->polynom;
}
data >>= 1;
}
}
uint32_t crc_finish(crc_t *crc) {
uint32_t val = crc->state;
if (crc->refout)
val = reflect(val, crc->order);
return ( val ^ crc->final_xor ) & crc->mask;
}
/*
static void print_crc(crc_t *crc) {
printf(" Order %d\n Poly %x\n Init %x\n Final %x\n Mask %x\n topbit %x\n RefIn %s\n RefOut %s\n State %x\n",
crc->order,
crc->polynom,
crc->initial_value,
crc->final_xor,
crc->mask,
crc->topbit,
(crc->refin) ? "TRUE":"FALSE",
(crc->refout) ? "TRUE":"FALSE",
crc->state
);
}
*/
// width=8 poly=0x31 init=0x00 refin=true refout=true xorout=0x00 check=0xA1 name="CRC-8/MAXIM"
uint32_t CRC8Maxim(uint8_t *buff, size_t size) {
crc_t crc;
crc_init_ref(&crc, 8, 0x31, 0, 0, true, true);
for ( int i=0; i < size; ++i)
crc_update2(&crc, buff[i], 8);
return crc_finish(&crc);
}
// width=8 poly=0x1d, reversed poly=0x?? init=0xe3 refin=true refout=true xorout=0x0000 check=0xC6 name="CRC-8/MAD"
// the CRC needs to be reversed before returned.
uint32_t CRC8Mad(uint8_t *buff, size_t size) {
crc_t crc;
crc_init_ref(&crc, 8, 0x1d, 0xe3, 0, true, true);
for ( int i = 0; i < size; ++i)
crc_update2(&crc, buff[i], 8);
return reflect8(crc_finish(&crc));
}
// width=4 poly=0xC, reversed poly=0x7 init=0x5 refin=true refout=true xorout=0x0000 check= name="CRC-4/LEGIC"
uint32_t CRC4Legic(uint8_t *cmd, size_t size) {
crc_t crc;
crc_init_ref(&crc, 4, 0x19 >> 1, 0x5, 0, true, true);
crc_update2(&crc, 1, 1); /* CMD_READ */
crc_update2(&crc, cmd[0], 8);
crc_update2(&crc, cmd[1], 8);
return reflect(crc_finish(&crc), 4);
}
// width=8 poly=0x63, reversed poly=0x8D init=0x55 refin=true refout=true xorout=0x0000 check=0xC6 name="CRC-8/LEGIC"
// the CRC needs to be reversed before returned.
uint32_t CRC8Legic(uint8_t *buff, size_t size) {
crc_t crc;
crc_init_ref(&crc, 8, 0x63, 0x55, 0, true, true);
for ( int i = 0; i < size; ++i)
crc_update2(&crc, buff[i], 8);
return reflect8(crc_finish(&crc));
}