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Moved iclass crc to be based on a lookup table

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This commit is contained in:
Martin Holst Swende 2015-01-04 22:10:25 +01:00
parent 337818f7ab
commit 39d3ce5dd6
2 changed files with 18 additions and 10 deletions
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24
armsrc/iclass.c
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@ -1595,6 +1595,15 @@ void ReaderIClass(uint8_t arg0) {
void ReaderIClass_Replay(uint8_t arg0, uint8_t *MAC) {
uint8_t card_data[24]={0};
uint16_t block_crc_LUT[255] = {0};
{//Generate a lookup table for block crc
for(int block = 0; block < 255; block++){
char bl = block;
block_crc_LUT[block] = iclass_crc16(&bl ,1);
}
}
//Dbprintf("Lookup table: %02x %02x %02x" ,block_crc_LUT[0],block_crc_LUT[1],block_crc_LUT[2]);
uint8_t check[] = { 0x05, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
uint8_t read[] = { 0x0c, 0x00, 0x00, 0x00 };
@ -1618,12 +1627,13 @@ void ReaderIClass_Replay(uint8_t arg0, uint8_t *MAC) {
while(!BUTTON_PRESS()) {
WDT_HIT();
if(traceLen > TRACE_SIZE) {
DbpString("Trace full");
break;
}
uint8_t read_status = handshakeIclassTag(card_data);
if(read_status < 2) continue;
@ -1636,16 +1646,15 @@ void ReaderIClass_Replay(uint8_t arg0, uint8_t *MAC) {
continue;
}
//first get configuration block
//first get configuration block (block 1)
crc = block_crc_LUT[1];
read[1]=1;
uint8_t *blockno=&read[1];
crc = iclass_crc16((char *)blockno,1);
read[2] = crc >> 8;
read[3] = crc & 0xff;
if(sendCmdGetResponseWithRetries(read, sizeof(read),resp, 10, 10))
{
Dbprintf("Dump config block failed");
Dbprintf("Dump config (block 1) failed");
continue;
}
@ -1660,10 +1669,10 @@ void ReaderIClass_Replay(uint8_t arg0, uint8_t *MAC) {
WDT_HIT();
//then loop around remaining blocks
for(char block=0; block < cardsize; block++){
for(int block=0; block < cardsize; block++){
read[1]= block;
crc = iclass_crc16(&block ,1);
crc = block_crc_LUT[block];
read[2] = crc >> 8;
read[3] = crc & 0xff;
@ -1681,7 +1690,6 @@ void ReaderIClass_Replay(uint8_t arg0, uint8_t *MAC) {
}
//If we got here, let's break
break;
WDT_HIT();
}
LED_A_OFF();
}

4
common/iso15693tools.c
View file

@ -66,11 +66,11 @@ char* Iso15693sprintUID(char *target,uint8_t *uid) {
return target;
}
unsigned short iclass_crc16(char *data_p, unsigned short length)
uint16_t iclass_crc16(char *data_p, unsigned short length)
{
unsigned char i;
unsigned int data;
unsigned int crc = 0xffff;
uint16_t crc = 0xffff;
if (length == 0)
return (~crc);