CHG: @marshmellow42 's em4x50 changes

[proxmark3-svn] / client / cmdlfem4x.c

diff --git a/client/cmdlfem4x.c b/client/cmdlfem4x.c
index 2cc034300c020c8bbdc81ecf39acf767550e2f43..839ad57c94001938ddc0ab5c7d252e215f48475b 100644 (file)
--- a/client/cmdlfem4x.c
+++ b/client/cmdlfem4x.c
@@ -533,6 +533,9 @@ uint8_t EMpreambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, siz
        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;
@@ -546,7 +549,6 @@ int demodEM4x05resp(uint8_t bitsNeeded) {
                ans = FSKrawDemod("0 0", false);
                if (!ans) {
                        if (g_debugMode) PrintAndLog("DEBUG: Error - EM4305: FSK Demod failed");
-                       //return -1;
                } else {
                        // set size to 10 to only test first 4 positions for the preamble
                        size_t size = (10 > DemodBufferLen) ? DemodBufferLen : 10;
@@ -557,7 +559,6 @@ int demodEM4x05resp(uint8_t bitsNeeded) {
                        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);
-                               //return -1;
                        } else {
                                //can't test size because the preamble doesn't repeat :(
                                //meaning chances of false positives are high.
@@ -565,11 +566,38 @@ int demodEM4x05resp(uint8_t bitsNeeded) {
                        }
                }
        }
-
+       // 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;
+               // try manchester - NOTE: ST only applies to T55x7 tags.
+               ans = ASKDemod_ext("0,0,1", false, false, 1, false);
+               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;
+                       size_t 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;
@@ -599,11 +627,10 @@ int demodEM4x05resp(uint8_t bitsNeeded) {
 
        if (!demodFound) {
                DemodBufferLen = 0x00;
-               // try manchester - NOTE: ST only applies to T55x7 tags.
-               ans = ASKDemod_ext("0,0,1", false, false, 1, false);
+               //try diphase (differential biphase or inverted)
+               ans = ASKbiphaseDemod("0 1 1", FALSE);
                if (!ans) {
-                       if (g_debugMode) PrintAndLog("DEBUG: Error - EM4305: ASK/Manchester Demod failed");
-                       //return -1;
+                       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;
@@ -614,7 +641,6 @@ int demodEM4x05resp(uint8_t bitsNeeded) {
                        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);
-                               //return -1;
                        } else {
                                //can't test size because the preamble doesn't repeat :(
                                //meaning chances of false positives are high.
@@ -624,8 +650,10 @@ int demodEM4x05resp(uint8_t bitsNeeded) {
        }
 
        if (demodFound && bitsNeeded < DemodBufferLen) {
+               if (bitsNeeded > 0) {
                setDemodBuf(DemodBuffer + ans + sizeof(preamble), bitsNeeded, 0);
                CmdPrintDemodBuff("x");
+               }
                return 1;
        }
        return -1;
@@ -673,10 +701,9 @@ int CmdReadWord(const char *Cmd) {
                return -1;
        }
 
-       //need 32 bits for read word
-       demodEM4x05resp(32);
-       
-       return 1;
+       //attempt demod:
+       //need 32 bits from a read word
+       return demodEM4x05resp(32);
 }
 
 int usage_lf_em_write(void) {
@@ -739,26 +766,15 @@ int CmdWriteWord(const char *Cmd) {
        }
        setGraphBuf(got, sizeof(got));
        
-       int ans = 0;
-       //bool ST = true;
-       DemodBufferLen = 0x00;  
-
-       //ans = ASKDemod_ext("0 0 1", FALSE, FALSE, 1, &ST);
-       ans = ASKbiphaseDemod("0 0 1", FALSE);
-       if (!ans) { 
-               if (g_debugMode) PrintAndLog("DEBUG: Error - EM4305: ASK/Manchester Demod failed");
-               return -3;
-       }
+       //todo: check response for 00001010 then write data for write confirmation!
        
-       //todo: check response for 00001010 then write data for write confirmation!     
-       size_t startIdx = 0, size = DemodBufferLen; 
-
-       uint8_t preamble[8] = {0,0,0,0,1,0,1,0};                
-       if (!preambleSearch(DemodBuffer, preamble, sizeof(preamble), &size, &startIdx)){
-               if (g_debugMode) PrintAndLog("DEBUG: Error - EM4305 preamble not found :: %d", startIdx);
-               return -4;
+       //attempt demod:
+       //need 0 bits demoded (after preamble) to verify write cmd
+       int result = demodEM4x05resp(0);
+       if (result == 1) {
+               PrintAndLog("Write Verified");
        }
-       PrintAndLog("Write OK");
+       return result;
        return 0;
 }