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refactor gProxII demod... add 0 spacer to ...

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... parity functions (remove, add)
make MAX_GRAPH_TRACE_LEN match with client side
This commit is contained in:
marshmellow42 2016-02-29 17:05:02 -05:00
commit 88e85bde41
3 changed files with 46 additions and 47 deletions
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67
client/cmddata.c
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@ -592,7 +592,7 @@ int Cmdaskbiphdemod(const char *Cmd)
int CmdG_Prox_II_Demod(const char *Cmd)
{
if (!ASKbiphaseDemod(Cmd, FALSE)){
if (g_debugMode) PrintAndLog("ASKbiphaseDemod failed 1st try");
if (g_debugMode) PrintAndLog("Error gProxII: ASKbiphaseDemod failed 1st try");
return 0;
}
size_t size = DemodBufferLen;
@ -602,46 +602,32 @@ int CmdG_Prox_II_Demod(const char *Cmd)
if (g_debugMode) PrintAndLog("Error gProxII_Demod");
return 0;
}
//got a good demod
uint32_t ByteStream[65] = {0x00};
//got a good demod of 96 bits
uint32_t ByteStream[8] = {0x00};
uint8_t xorKey=0;
uint8_t keyCnt=0;
uint8_t bitCnt=0;
uint8_t ByteCnt=0;
size_t startIdx = ans + 6; //start after preamble
for (size_t idx = 0; idx<size-6; idx++){
if ((idx+1) % 5 == 0){
//spacer bit - should be 0
if (DemodBuffer[startIdx+idx] != 0) {
if (g_debugMode) PrintAndLog("Error spacer not 0: %u, pos: %u", (unsigned int)DemodBuffer[startIdx+idx],(unsigned int)(startIdx+idx));
return 0;
}
continue;
}
if (keyCnt<8){ //lsb first
xorKey = xorKey | (DemodBuffer[startIdx+idx]<<keyCnt);
keyCnt++;
if (keyCnt==8 && g_debugMode) PrintAndLog("xorKey Found: %02x", (unsigned int)xorKey);
continue;
}
//lsb first
ByteStream[ByteCnt] = ByteStream[ByteCnt] | (DemodBuffer[startIdx+idx]<<bitCnt);
bitCnt++;
if (bitCnt % 8 == 0){
if (g_debugMode) PrintAndLog("byte %u: %02x", (unsigned int)ByteCnt, ByteStream[ByteCnt]);
bitCnt=0;
ByteCnt++;
}
size_t startIdx = ans + 6; //start after 6 bit preamble
uint8_t bits_no_spacer[90];
//so as to not mess with raw DemodBuffer copy to a new sample array
memcpy(bits_no_spacer, DemodBuffer + startIdx, 90);
// remove the 18 (90/5=18) parity bits (down to 72 bits (96-6-18=72))
size_t bitLen = removeParity(bits_no_spacer, 0, 5, 3, 90); //source, startloc, paritylen, ptype, length_to_run
if (bitLen != 72) {
if (g_debugMode) PrintAndLog("Error gProxII: spacer removal did not produce 72 bits: %u, start: %u", bitLen, startIdx);
return 0;
}
for (uint8_t i = 0; i < ByteCnt; i++){
ByteStream[i] ^= xorKey; //xor
if (g_debugMode) PrintAndLog("byte %u after xor: %02x", (unsigned int)i, ByteStream[i]);
// get key and then get all 8 bytes of payload decoded
xorKey = (uint8_t)bytebits_to_byteLSBF(bits_no_spacer, 8);
for (size_t idx = 0; idx < 8; idx++) {
ByteStream[idx] = ((uint8_t)bytebits_to_byteLSBF(bits_no_spacer+8 + (idx*8),8)) ^ xorKey;
if (g_debugMode) PrintAndLog("byte %u after xor: %02x", (unsigned int)idx, ByteStream[idx]);
}
//now ByteStream contains 64 bytes of decrypted raw tag data
//now ByteStream contains 8 Bytes (64 bits) of decrypted raw tag data
//
uint8_t fmtLen = ByteStream[0]>>2;
uint32_t FC = 0;
uint32_t Card = 0;
//get raw 96 bits to print
uint32_t raw1 = bytebits_to_byte(DemodBuffer+ans,32);
uint32_t raw2 = bytebits_to_byte(DemodBuffer+ans+32, 32);
uint32_t raw3 = bytebits_to_byte(DemodBuffer+ans+64, 32);
@ -649,13 +635,22 @@ int CmdG_Prox_II_Demod(const char *Cmd)
if (fmtLen==36){
FC = ((ByteStream[3] & 0x7F)<<7) | (ByteStream[4]>>1);
Card = ((ByteStream[4]&1)<<19) | (ByteStream[5]<<11) | (ByteStream[6]<<3) | (ByteStream[7]>>5);
PrintAndLog("G-Prox-II Found: FmtLen %d, FC %d, Card %d", fmtLen, FC, Card);
PrintAndLog("G-Prox-II Found: FmtLen %d, FC %u, Card %u", (int)fmtLen, FC, Card);
} else if(fmtLen==26){
FC = ((ByteStream[3] & 0x7F)<<1) | (ByteStream[4]>>7);
Card = ((ByteStream[4]&0x7F)<<9) | (ByteStream[5]<<1) | (ByteStream[6]>>7);
PrintAndLog("G-Prox-II Found: FmtLen %d, FC %d, Card %d",(unsigned int)fmtLen,FC,Card);
PrintAndLog("G-Prox-II Found: FmtLen %d, FC %u, Card %u", (int)fmtLen, FC, Card);
} else {
PrintAndLog("Unknown G-Prox-II Fmt Found: FmtLen %d",(int)fmtLen);
PrintAndLog("Decoded Raw: %02x%02x%02x%02x%02x%02x%02x%02x",
ByteStream[0],
ByteStream[1],
ByteStream[2],
ByteStream[3],
ByteStream[4],
ByteStream[5],
ByteStream[6],
ByteStream[7]);
}
PrintAndLog("Raw: %08x%08x%08x", raw1,raw2,raw3);
setDemodBuf(DemodBuffer+ans, 96, 0);