X-Git-Url: https://git.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/34ff898553f3392c66c50d1a524070882d237fb5..571324a5c4b3edf7460633ca66ca5081aa4fdc6b:/common/lfdemod.c?ds=sidebyside diff --git a/common/lfdemod.c b/common/lfdemod.c index 406b0445..3f597a1f 100644 --- a/common/lfdemod.c +++ b/common/lfdemod.c @@ -78,7 +78,7 @@ size_t removeParity(uint8_t *BitStream, size_t startIdx, uint8_t pLen, uint8_t p parityWd = (parityWd << 1) | BitStream[startIdx+word+bit]; BitStream[j++] = (BitStream[startIdx+word+bit]); } - if (word+pLen >= bLen) break; + if (word+pLen > bLen) break; j--; // overwrite parity with next data // if parity fails then return 0 @@ -150,40 +150,30 @@ 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) { + return (preambleSearchEx(BitStream, preamble, pLen, size, startIdx, false)) ? 1 : 0; +} + +// search for given preamble in given BitStream and return success=1 or fail=0 and startIndex (where it was found) and length if not fineone +// fineone does not look for a repeating preamble for em4x05/4x69 sends preamble once, so look for it once in the first pLen bits +bool preambleSearchEx(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx, bool findone) { // Sanity check. If preamble length is bigger than bitstream length. - if ( *size <= pLen ) return 0; + if ( *size <= pLen ) return false; - uint8_t foundCnt=0; - for (int idx=0; idx < *size - pLen; idx++){ - if (memcmp(BitStream+idx, preamble, pLen) == 0){ + uint8_t foundCnt = 0; + for (size_t idx = 0; idx < *size - pLen; idx++) { + if (memcmp(BitStream+idx, preamble, pLen) == 0) { //first index found foundCnt++; - if (foundCnt == 1){ + if (foundCnt == 1) { + if (g_debugMode) prnt("DEBUG: preamble found at %u", idx); *startIdx = idx; - } - if (foundCnt == 2){ + if (findone) return true; + } else if (foundCnt == 2) { *size = idx - *startIdx; - return 1; + return true; } } } - 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; } @@ -217,39 +207,32 @@ size_t findModStart(uint8_t dest[], size_t size, uint8_t threshold_value, uint8_ //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) { - //no arguments needed - built this way in case we want this to be a direct call from "data " cmds in the future - // otherwise could be a void with no arguments - //set defaults - uint32_t i = 0; + //sanity checks + if (*size < 64) return 0; if (BitStream[1]>1) return 0; //allow only 1s and 0s // 111111111 bit pattern represent start of frame // include 0 in front to help get start pos uint8_t preamble[] = {0,1,1,1,1,1,1,1,1,1}; - uint32_t idx = 0; - uint32_t parityBits = 0; uint8_t errChk = 0; - uint8_t FmtLen = 10; + uint8_t FmtLen = 10; // sets of 4 bits = end data *startIdx = 0; errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, startIdx); - if (errChk == 0 || *size < 64) return 0; - if (*size > 64) FmtLen = 22; - *startIdx += 1; //get rid of 0 from preamble - idx = *startIdx + 9; - for (i=0; i> 63); - *lo = (*lo << 1) | (BitStream[(i*5)+ii+idx]); - } + if ( errChk == 0 || (*size != 64 && *size != 128) ) return 0; + if (*size == 128) FmtLen = 22; // 22 sets of 4 bits + + //skip last 4bit parity row for simplicity + *size = removeParity(BitStream, *startIdx + sizeof(preamble), 5, 0, FmtLen * 5); + if (*size == 40) { // std em410x format + *hi = 0; + *lo = ((uint64_t)(bytebits_to_byte(BitStream, 8)) << 32) | (bytebits_to_byte(BitStream + 8, 32)); + } else if (*size == 88) { // long em format + *hi = (bytebits_to_byte(BitStream, 24)); + *lo = ((uint64_t)(bytebits_to_byte(BitStream + 24, 32)) << 32) | (bytebits_to_byte(BitStream + 24 + 32, 32)); + } else { + return 0; } - if (errChk != 0) return 1; - //skip last 5 bit parity test for simplicity. - // *size = 64 | 128; - return 0; + return 1; } //by marshmellow @@ -305,6 +288,7 @@ int cleanAskRawDemod(uint8_t *BinStream, size_t *size, int clk, int invert, int } //by marshmellow +//amplify based on ask edge detection void askAmp(uint8_t *BitStream, size_t size) { uint8_t Last = 128; @@ -1343,7 +1327,10 @@ uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fc continue; // else new peak // if we got less than the small fc + tolerance then set it to the small fc - if (fcCounter < fcLow+fcTol) + // if it is inbetween set it to the last counter + if (fcCounter < fcHigh && fcCounter > fcLow) + fcCounter = lastFCcnt; + else if (fcCounter < fcLow+fcTol) fcCounter = fcLow; else //set it to the large fc fcCounter = fcHigh; @@ -1409,7 +1396,7 @@ uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fc } } - if (ii<0) return 0; // oops we went too far + if (ii<2) return 0; // oops we went too far return clk[ii]; } @@ -1609,9 +1596,14 @@ int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert) return errCnt; } +bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) { + size_t ststart = 0, stend = 0; + return DetectST_ext(buffer, size, foundclock, &ststart, &stend); +} + //by marshmellow //attempt to identify a Sequence Terminator in ASK modulated raw wave -bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) { +bool DetectST_ext(uint8_t buffer[], size_t *size, int *foundclock, size_t *ststart, size_t *stend) { size_t bufsize = *size; //need to loop through all samples and identify our clock, look for the ST pattern uint8_t fndClk[] = {8,16,32,40,50,64,128}; @@ -1764,7 +1756,7 @@ bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) { size_t newloc = 0; i=0; if (g_debugMode==2) prnt("DEBUG STT: Starting STT trim - start: %d, datalen: %d ",dataloc, datalen); - + bool firstrun = true; // warning - overwriting buffer given with raw wave data with ST removed... while ( dataloc < bufsize-(clk/2) ) { //compensate for long high at end of ST not being high due to signal loss... (and we cut out the start of wave high part) @@ -1772,6 +1764,15 @@ bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) { for(i=0; i < clk/2-tol; ++i) { buffer[dataloc+i] = high+5; } + } //test for single sample outlier (high between two lows) in the case of very strong waves + if (buffer[dataloc] >= high && buffer[dataloc+2] <= low) { + buffer[dataloc] = buffer[dataloc+2]; + buffer[dataloc+1] = buffer[dataloc+2]; + } + if (firstrun) { + *stend = dataloc; + *ststart = dataloc-(clk*4); + firstrun=false; } for (i=0; i