X-Git-Url: http://cvs.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/c783fd1bb83f9f655893b1f349bbdf26ede00a6f..34ff898553f3392c66c50d1a524070882d237fb5:/common/lfdemod.c diff --git a/common/lfdemod.c b/common/lfdemod.c index 8324c440..406b0445 100644 --- a/common/lfdemod.c +++ b/common/lfdemod.c @@ -62,7 +62,7 @@ uint8_t parityTest(uint32_t bits, uint8_t bitLen, uint8_t pType) for (uint8_t i = 0; i < bitLen; i++){ ans ^= ((bits >> i) & 1); } - //PrintAndLog("DEBUG: ans: %d, ptype: %d",ans,pType); + if (g_debugMode) prnt("DEBUG: ans: %d, ptype: %d, bits: %08X",ans,pType,bits); return (ans == pType); } @@ -73,11 +73,13 @@ size_t removeParity(uint8_t *BitStream, size_t startIdx, uint8_t pLen, uint8_t p { uint32_t parityWd = 0; size_t j = 0, bitCnt = 0; - for (int word = 0; word < (bLen); word+=pLen){ - for (int bit=0; bit < pLen; bit++){ + for (int word = 0; word < (bLen); word+=pLen) { + for (int bit=0; bit < pLen; bit++) { parityWd = (parityWd << 1) | BitStream[startIdx+word+bit]; BitStream[j++] = (BitStream[startIdx+word+bit]); } + if (word+pLen >= bLen) break; + j--; // overwrite parity with next data // if parity fails then return 0 switch (pType) { @@ -148,6 +150,9 @@ 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) { + // 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){ @@ -165,6 +170,49 @@ uint8_t preambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_ return 0; } +// search for given preamble in given BitStream and return success=1 or fail=0 and startIndex (where it was found) +// does not look for a repeating preamble +// em4x05/4x69 only sends preamble once, so look for it once in the first pLen bits +// leave it generic so it could be reused later... +bool onePreambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t size, size_t *startIdx) { + // Sanity check. If preamble length is bigger than bitstream length. + if ( size <= pLen ) return false; + for (size_t idx = 0; idx < size - pLen; idx++) { + if (memcmp(BitStream+idx, preamble, pLen) == 0) { + if (g_debugMode) prnt("DEBUG: preamble found at %u", idx); + *startIdx = idx; + return true; + } + } + return false; +} + +// find start of modulating data (for fsk and psk) in case of beginning noise or slow chip startup. +size_t findModStart(uint8_t dest[], size_t size, uint8_t threshold_value, uint8_t expWaveSize) { + size_t i = 0; + size_t waveSizeCnt = 0; + uint8_t thresholdCnt = 0; + bool isAboveThreshold = dest[i++] >= threshold_value; + for (; i < size-20; i++ ) { + if(dest[i] < threshold_value && isAboveThreshold) { + thresholdCnt++; + if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break; + isAboveThreshold = false; + waveSizeCnt = 0; + } else if (dest[i] >= threshold_value && !isAboveThreshold) { + thresholdCnt++; + if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break; + isAboveThreshold = true; + waveSizeCnt = 0; + } else { + waveSizeCnt++; + } + if (thresholdCnt > 10) break; + } + if (g_debugMode == 2) prnt("DEBUG: threshold Count reached at %u, count: %u",i, thresholdCnt); + return i; +} + //by marshmellow //takes 1s and 0s and searches for EM410x format - output EM ID uint8_t Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_t *hi, uint64_t *lo) @@ -474,7 +522,6 @@ size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow { size_t last_transition = 0; size_t idx = 1; - //uint32_t maxVal=0; if (fchigh==0) fchigh=10; if (fclow==0) fclow=8; //set the threshold close to 0 (graph) or 128 std to avoid static @@ -482,19 +529,22 @@ size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow size_t preLastSample = 0; size_t LastSample = 0; size_t currSample = 0; - // sync to first lo-hi transition, and threshold + if ( size < 1024 ) return 0; // not enough samples + + //find start of modulating data in trace + idx = findModStart(dest, size, threshold_value, fchigh); // Need to threshold first sample - // skip 160 samples to allow antenna/samples to settle - if(dest[160] < threshold_value) dest[0] = 0; + if(dest[idx] < threshold_value) dest[0] = 0; else dest[0] = 1; - + idx++; + size_t numBits = 0; // count cycles between consecutive lo-hi transitions, there should be either 8 (fc/8) // or 10 (fc/10) cycles but in practice due to noise etc we may end up with anywhere // between 7 to 11 cycles so fuzz it by treat anything <9 as 8 and anything else as 10 // (could also be fc/5 && fc/7 for fsk1 = 4-9) - for(idx = 161; idx < size-20; idx++) { + for(; idx < size-20; idx++) { // threshold current value if (dest[idx] < threshold_value) dest[idx] = 0; @@ -509,13 +559,14 @@ size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow //do nothing with extra garbage } else if (currSample < (fchigh-1)) { //6-8 = 8 sample waves (or 3-6 = 5) //correct previous 9 wave surrounded by 8 waves (or 6 surrounded by 5) - if (LastSample > (fchigh-2) && (preLastSample < (fchigh-1) || preLastSample == 0 )){ + if (LastSample > (fchigh-2) && (preLastSample < (fchigh-1))){ dest[numBits-1]=1; } dest[numBits++]=1; - } else if (currSample > (fchigh) && !numBits) { //12 + and first bit = unusable garbage - //do nothing with beginning garbage + } else if (currSample > (fchigh+1) && numBits < 3) { //12 + and first two bit = unusable garbage + //do nothing with beginning garbage and reset.. should be rare.. + numBits = 0; } else if (currSample == (fclow+1) && LastSample == (fclow-1)) { // had a 7 then a 9 should be two 8's (or 4 then a 6 should be two 5's) dest[numBits++]=1; } else { //9+ = 10 sample waves (or 6+ = 7) @@ -1372,10 +1423,10 @@ uint16_t countFC(uint8_t *BitStream, size_t size, uint8_t fskAdj) uint8_t fcLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}; uint16_t fcCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}; uint8_t fcLensFnd = 0; - uint8_t lastFCcnt=0; + uint8_t lastFCcnt = 0; uint8_t fcCounter = 0; size_t i; - if (size == 0) return 0; + if (size < 180) return 0; // prime i to first up transition for (i = 160; i < size-20; i++) @@ -1462,27 +1513,37 @@ int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert) size_t numBits=0; uint8_t curPhase = *invert; - size_t i, waveStart=1, waveEnd=0, firstFullWave=0, lastClkBit=0; - uint8_t fc=0, fullWaveLen=0, tol=1; - uint16_t errCnt=0, waveLenCnt=0; - fc = countFC(dest, *size, 0); + size_t i=0, waveStart=1, waveEnd=0, firstFullWave=0, lastClkBit=0; + uint16_t fc=0, fullWaveLen=0, tol=1; + uint16_t errCnt=0, waveLenCnt=0, errCnt2=0; + fc = countFC(dest, *size, 1); + uint8_t fc2 = fc >> 8; + if (fc2 == 10) return -1; //fsk found - quit + fc = fc & 0xFF; if (fc!=2 && fc!=4 && fc!=8) return -1; //PrintAndLog("DEBUG: FC: %d",fc); *clock = DetectPSKClock(dest, *size, *clock); if (*clock == 0) return -1; - int avgWaveVal=0, lastAvgWaveVal=0; + + //find start of modulating data in trace + uint8_t threshold_value = 123; //-5 + i = findModStart(dest, *size, threshold_value, fc); + //find first phase shift - for (i=0; i= dest[i+2]){ waveEnd = i+1; - //PrintAndLog("DEBUG: waveEnd: %d",waveEnd); + if (g_debugMode == 2) prnt("DEBUG PSK: waveEnd: %u, waveStart: %u",waveEnd, waveStart); waveLenCnt = waveEnd-waveStart; - if (waveLenCnt > fc && waveStart > fc && !(waveLenCnt > fc+2)){ //not first peak and is a large wave but not out of whack + if (waveLenCnt > fc && waveStart > fc && !(waveLenCnt > fc+3)){ //not first peak and is a large wave but not out of whack lastAvgWaveVal = avgWaveVal/(waveLenCnt); firstFullWave = waveStart; fullWaveLen=waveLenCnt; - //if average wave value is > graph 0 then it is an up wave or a 1 - if (lastAvgWaveVal > 123) curPhase ^= 1; //fudge graph 0 a little 123 vs 128 + //if average wave value is > graph 0 then it is an up wave or a 1 (could cause inverting) + if (lastAvgWaveVal > threshold_value) curPhase ^= 1; break; } waveStart = i+1; @@ -1503,7 +1564,7 @@ int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert) //set start of wave as clock align lastClkBit = firstFullWave; if (g_debugMode==2) prnt("DEBUG PSK: firstFullWave: %u, waveLen: %u",firstFullWave,fullWaveLen); - if (g_debugMode==2) prnt("DEBUG: clk: %d, lastClkBit: %u, fc: %u", *clock, lastClkBit,(unsigned int) fc); + if (g_debugMode==2) prnt("DEBUG PSK: clk: %d, lastClkBit: %u, fc: %u", *clock, lastClkBit,(unsigned int) fc); waveStart = 0; dest[numBits++] = curPhase; //set first read bit for (i = firstFullWave + fullWaveLen - 1; i < *size-3; i++){ @@ -1534,6 +1595,9 @@ int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert) } else if (i+1 > lastClkBit + *clock + tol + fc){ lastClkBit += *clock; //no phase shift but clock bit dest[numBits++] = curPhase; + } else if (waveLenCnt < fc - 1) { //wave is smaller than field clock (shouldn't happen often) + errCnt2++; + if(errCnt2 > 101) return errCnt2; } avgWaveVal = 0; waveStart = i+1;