X-Git-Url: http://cvs.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/0cbe0cb8d6ab56fae79fd757b42b0667d37f48c8..9015ae0f5dec6a7922ff6ce30eb62ad7a0e6cf5b:/common/lfdemod.c

diff --git a/common/lfdemod.c b/common/lfdemod.c
index 8b31f1a4..d9a87583 100644
--- a/common/lfdemod.c
+++ b/common/lfdemod.c
@@ -81,10 +81,9 @@ size_t removeParity(uint8_t *BitStream, size_t startIdx, uint8_t pLen, uint8_t p
 		j--; // overwrite parity with next data
 		// if parity fails then return 0
 		switch (pType) {
-			case 3: if (BitStream[j]==1) return 0; break; //should be 0 spacer bit
-			case 2: if (BitStream[j]==0) return 0; break; //should be 1 spacer bit
-			default: //test parity
-				if (parityTest(parityWd, pLen, pType) == 0) return 0; break;
+			case 3:  if (BitStream[j]==1) { return 0; } break; //should be 0 spacer bit
+			case 2:  if (BitStream[j]==0) { return 0; } break; //should be 1 spacer bit
+			default: if (parityTest(parityWd, pLen, pType) == 0) { return 0; } break; //test parity
 		}
 		bitCnt+=(pLen-1);
 		parityWd = 0;
@@ -148,8 +147,11 @@ uint32_t bytebits_to_byteLSBF(uint8_t *src, size_t numbits)
 //search for given preamble in given BitStream and return success=1 or fail=0 and startIndex and length
 uint8_t preambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx)
 {
-	uint8_t foundCnt=0;
-	for (int idx=0; idx < *size - pLen; idx++){
+	// Sanity check.  If preamble length is bigger than bitstream length.
+	if ( *size <= pLen ) return 0;
+	
+	uint8_t foundCnt = 0;
+	for (int idx = 0; idx < *size - pLen; idx++){
 		if (memcmp(BitStream+idx, preamble, pLen) == 0){
 			//first index found
 			foundCnt++;
@@ -582,7 +584,7 @@ int HIDdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32
 {
 	if (justNoise(dest, *size)) return -1;
 
-	size_t numStart=0, size2=*size, startIdx=0; 
+	size_t numStart=0, size2 = *size, startIdx=0; 
 	// FSK demodulator
 	*size = fskdemod(dest, size2,50,1,10,8); //fsk2a
 	if (*size < 96*2) return -2;
@@ -614,7 +616,7 @@ int ParadoxdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, ui
 {
 	if (justNoise(dest, *size)) return -1;
 	
-	size_t numStart=0, size2=*size, startIdx=0;
+	size_t numStart=0, size2 = *size, startIdx=0;
 	// FSK demodulator
 	*size = fskdemod(dest, size2,50,1,10,8); //fsk2a
 	if (*size < 96) return -2;
@@ -723,6 +725,39 @@ int FDXBdemodBI(uint8_t *dest, size_t *size)
 	return (int)startIdx;
 }
 
+// ASK/Diphase fc/64 (inverted Biphase)
+// Note: this i s not a demod, this is only a detection
+// the parameter *dest needs to be demoded before call
+int JablotronDemod(uint8_t *dest, size_t *size){
+	//make sure buffer has enough data
+	if (*size < 64) return -1;
+
+	size_t startIdx = 0;
+	// 0xFFFF preamble, 64bits
+	uint8_t preamble[] = {
+		        1,1,1,1,
+	            1,1,1,1,
+				1,1,1,1,
+				1,1,1,1,
+				0
+		};
+
+	uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
+	if (errChk == 0) return -4; //preamble not found
+	if (*size != 64) return -3;
+	
+	uint8_t checkchksum = 0;
+	for (int i=16; i < 56; i += 8) {
+		checkchksum += bytebits_to_byte(dest+startIdx+i,8);
+	}
+	checkchksum ^= 0x3A;
+
+	uint8_t crc = bytebits_to_byte(dest+startIdx+56, 8);
+	
+	if ( checkchksum != crc ) return -5;	
+	return (int)startIdx;
+}
+
 // by marshmellow
 // FSK Demod then try to locate an AWID ID
 int AWIDdemodFSK(uint8_t *dest, size_t *size)