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

[proxmark3-svn] / client / cmddata.c

diff --git a/client/cmddata.c b/client/cmddata.c
index f2d4d8834a271e4f3b71fdf2fbb8e79e06f6cec3..2a2a0dc1c78a6c4b6a1e5432a2916d0e40390356 100644 (file)
--- a/client/cmddata.c
+++ b/client/cmddata.c
@@ -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);