X-Git-Url: http://git.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/7666f4608e8ade0ada08777d1cc33469c5d9471d..2d99d9912c430b09c8178c9154a44a99e7ee6561:/client/cmdlfem4x.c

diff --git a/client/cmdlfem4x.c b/client/cmdlfem4x.c
index aa568e9e..2d1600f6 100644
--- a/client/cmdlfem4x.c
+++ b/client/cmdlfem4x.c
@@ -512,6 +512,153 @@ int usage_lf_em_read(void) {
 	PrintAndLog("      lf em readword 1 11223344");
 	return 0;
 }
+
+//search for given preamble in given BitStream and return success=1 or fail=0 and startIndex
+uint8_t EMpreambleSearch(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;
+	// em only sends preamble once, so look for it once in the first x bits
+	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 (g_debugMode) PrintAndLog("DEBUG: preamble found at %u", idx);
+				*startIdx = idx;
+				return 1;
+			}
+		}
+	}
+	return 0;
+}
+
+// FSK, PSK, ASK/MANCHESTER, ASK/BIPHASE, ASK/DIPHASE 
+// should cover 90% of known used configs
+// the rest will need to be manually demoded for now...
+int demodEM4x05resp(uint8_t bitsNeeded) {
+	int ans = 0;
+	bool demodFound = false;
+	DemodBufferLen = 0x00;
+	// skip first two 0 bits as they might have been missed in the demod 
+	uint8_t preamble[6] = {0,0,1,0,1,0};
+	size_t startIdx = 0; 
+
+	// test for FSK wave (easiest to 99% ID)
+	if (GetFskClock("", FALSE, FALSE)) {
+		//valid fsk clocks found
+		ans = FSKrawDemod("0 0", false);
+		if (!ans) {
+			if (g_debugMode) PrintAndLog("DEBUG: Error - EM4305: FSK Demod failed");
+		} else {
+			// set size to 10 to only test first 4 positions for the preamble
+			size_t size = (10 > DemodBufferLen) ? DemodBufferLen : 10;
+			startIdx = 0; 
+
+			if (g_debugMode) PrintAndLog("ANS: %d | %u | %u", ans, startIdx, size);
+
+			uint8_t errChk = EMpreambleSearch(DemodBuffer, preamble, sizeof(preamble), size, &startIdx);
+			if ( errChk == 0) {
+				if (g_debugMode) PrintAndLog("DEBUG: Error - EM4305 preamble not found :: %d", startIdx);
+			} else {
+				//can't test size because the preamble doesn't repeat :(
+				//meaning chances of false positives are high.
+				demodFound = true;
+			}
+		}
+	}
+	// PSK clocks should be easy to detect ( but difficult to demod a non-repeating pattern... )
+	if (!demodFound) {
+		ans = GetPskClock("", FALSE, FALSE);
+		if (ans>0) {
+			PrintAndLog("PSK response possibly found, run `data rawd p1` to attempt to demod");
+		}
+	}
+
+	// more common than biphase
+	if (!demodFound) {
+		DemodBufferLen = 0x00;
+		bool stcheck = false;
+		// try manchester - NOTE: ST only applies to T55x7 tags.
+		ans = ASKDemod_ext("0,0,1", false, false, 1, &stcheck);
+		if (!ans) {
+			if (g_debugMode) PrintAndLog("DEBUG: Error - EM4305: ASK/Manchester Demod failed");
+		} else {
+			// set size to 10 to only test first 4 positions for the preamble
+			size_t size = (10 > DemodBufferLen) ? DemodBufferLen : 10;
+			startIdx = 0; 
+
+			if (g_debugMode) PrintAndLog("ANS: %d | %u | %u", ans, startIdx, size);
+
+			uint8_t errChk = EMpreambleSearch(DemodBuffer, preamble, sizeof(preamble), size, &startIdx);
+			if ( errChk == 0) {
+				if (g_debugMode) PrintAndLog("DEBUG: Error - EM4305 preamble not found :: %d", startIdx);
+			} else {
+				//can't test size because the preamble doesn't repeat :(
+				//meaning chances of false positives are high.
+				demodFound = true;
+			}
+		}
+	}
+
+	if (!demodFound) {
+		DemodBufferLen = 0x00;
+		//try biphase
+		ans = ASKbiphaseDemod("0 0 1", FALSE);
+		if (!ans) { 
+			if (g_debugMode) PrintAndLog("DEBUG: Error - EM4305: ASK/biphase Demod failed");
+		} else {
+			// set size to 10 to only test first 4 positions for the preamble
+			size_t size = (10 > DemodBufferLen) ? DemodBufferLen : 10;
+			startIdx = 0; 
+
+			if (g_debugMode) PrintAndLog("ANS: %d | %u | %u", ans, startIdx, size);
+
+			uint8_t errChk = EMpreambleSearch(DemodBuffer, preamble, sizeof(preamble), size, &startIdx);
+			if ( errChk == 0) {
+				if (g_debugMode) PrintAndLog("DEBUG: Error - EM4305 preamble not found :: %d", startIdx);
+			} else {
+				//can't test size because the preamble doesn't repeat :(
+				//meaning chances of false positives are high.
+				demodFound = true;
+			}
+		}
+	}
+
+	if (!demodFound) {
+		DemodBufferLen = 0x00;
+		//try diphase (differential biphase or inverted)
+		ans = ASKbiphaseDemod("0 1 1", FALSE);
+		if (!ans) { 
+			if (g_debugMode) PrintAndLog("DEBUG: Error - EM4305: ASK/biphase Demod failed");
+		} else {
+			// set size to 10 to only test first 4 positions for the preamble
+			size_t size = (10 > DemodBufferLen) ? DemodBufferLen : 10;
+			startIdx = 0; 
+
+			if (g_debugMode) PrintAndLog("ANS: %d | %u | %u", ans, startIdx, size);
+
+			uint8_t errChk = EMpreambleSearch(DemodBuffer, preamble, sizeof(preamble), size, &startIdx);
+			if ( errChk == 0) {
+				if (g_debugMode) PrintAndLog("DEBUG: Error - EM4305 preamble not found :: %d", startIdx);
+			} else {
+				//can't test size because the preamble doesn't repeat :(
+				//meaning chances of false positives are high.
+				demodFound = true;
+			}
+		}
+	}
+
+	if (demodFound && bitsNeeded < DemodBufferLen) {
+		if (bitsNeeded > 0) {
+			setDemodBuf(DemodBuffer + startIdx + sizeof(preamble), bitsNeeded, 0);
+			CmdPrintDemodBuff("x");			
+		}
+		return 1;
+	}
+	return -1;
+}
+
 int CmdReadWord(const char *Cmd) {
 	int addr, pwd;
 	bool usePwd = false;
@@ -540,16 +687,23 @@ int CmdReadWord(const char *Cmd) {
 		PrintAndLog("Command timed out");
 		return -1;
 	}
-	
-	uint8_t got[6000]; // 8 bit preamble + 32 bit word response (max clock (128) * 40bits = 5120 samples)
+
+	uint8_t got[6000];
 	GetFromBigBuf(got, sizeof(got), 0);
-	if ( !WaitForResponseTimeout(CMD_ACK, NULL, 8000) ) {
+	if ( !WaitForResponseTimeout(CMD_ACK, NULL, 2500) ) {
 		PrintAndLog("command execution time out");
-		return 0;
+		return -1;
 	}
 	setGraphBuf(got, sizeof(got));
-	//todo: demodulate read data 
-	return 1;
+	int testLen = (GraphTraceLen < 1000) ? GraphTraceLen : 1000;
+	if (graphJustNoise(GraphBuffer, testLen)) {
+		PrintAndLog("no tag not found");
+		return -1;
+	}
+
+	//attempt demod:
+	//need 32 bits from a read word
+	return demodEM4x05resp(44);
 }
 
 int usage_lf_em_write(void) {
@@ -566,6 +720,7 @@ int usage_lf_em_write(void) {
 	PrintAndLog("      lf em writeword 1 deadc0de 11223344");
 	return 0;
 }
+
 int CmdWriteWord(const char *Cmd) {
 	uint8_t ctmp = param_getchar(Cmd, 0);
 	if ( strlen(Cmd) == 0 || ctmp == 'H' || ctmp == 'h' ) return usage_lf_em_write();
@@ -611,7 +766,14 @@ int CmdWriteWord(const char *Cmd) {
 	}
 	setGraphBuf(got, sizeof(got));
 	//todo: check response for 00001010 then write data for write confirmation!
-	return 0;
+	
+	//attempt demod:
+	//need 0 bits demoded (after preamble) to verify write cmd
+	int result = demodEM4x05resp(0);
+	if (result == 1) {
+		PrintAndLog("Write Verified");
+	}
+	return result;
 }
 
 /*