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;
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) {
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();
}
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;
}
/*
projects / proxmark3-svn / blobdiff