Fix 15 snoop (#752)

* fixing hf 15: implement hf 15 snoop
* rename hf 15 record to hf 15 snoop
* speedup sampling / decoding:
*   new FPGA mode FPGA_HF_READER_RX_XCORR_AMPLITUDE implements amplitude(ci, cq) on FPGA
*   inlining the decoders in iso15693.c
*   inlining memcpy/memset in LogTrace()
*   giving up the moving correlator for SOF in Handle15693SamplesFromTag
* decode more of EOF in Handle15693SamplesFromTag()
* some refactoring

CHANGELOG.md

@@ -13,6 +13,7 @@ This project uses the changelog in accordance with [keepchangelog](http://keepac
 ### Fixed
 - AC-Mode decoding for HitagS
 - Wrong UID at HitagS simulation
+- 'hf 15 sim' now works as expected (piwi)
 
 ### Added
 - Support Standard Communication Mode in HITAG S
@@ -24,6 +25,7 @@ This project uses the changelog in accordance with [keepchangelog](http://keepac
 - Added `hf fido` `assert` and `make` commands from fido2 protocol (authenticatorMakeCredential and authenticatorGetAssertion) (Merlok)
 - Added `lf paradox clone` to clone a Paradox card
 - Added `emv` commmands working for both contactless and smart cards (Merlok)
+- Added 'hf 15 snoop' (piwi)
 
 
 ## [v3.1.0][2018-10-10]

armsrc/BigBuf.c

@@ -36,8 +36,8 @@ static uint16_t BigBuf_hi = BIGBUF_SIZE;
 static uint8_t *emulator_memory = NULL;
 
 // trace related variables
-static uint16_t traceLen = 0;
+static uint32_t traceLen = 0;
-int tracing = 1; //Last global one.. todo static?
+static bool tracing = true;
 
 // get the address of BigBuf
 uint8_t *BigBuf_get_addr(void)
@@ -66,7 +66,7 @@ void BigBuf_Clear(void)
 // clear ALL of BigBuf
 void BigBuf_Clear_ext(bool verbose)
 {
-	memset(BigBuf,0,BIGBUF_SIZE);
+	memset(BigBuf, 0, BIGBUF_SIZE);
 	if (verbose) 
 		Dbprintf("Buffer cleared (%i bytes)",BIGBUF_SIZE);
 }
@@ -76,7 +76,7 @@ void BigBuf_Clear_EM(void){
 
 void BigBuf_Clear_keep_EM(void)
 {
-	memset(BigBuf,0,BigBuf_hi);
+	memset(BigBuf, 0, BigBuf_hi);
 }
 
 // allocate a chunk of memory from BigBuf. We allocate high memory first. The unallocated memory
@@ -162,8 +162,8 @@ bool RAMFUNC LogTrace(const uint8_t *btBytes, uint16_t iLen, uint32_t timestamp_
 
 	uint8_t *trace = BigBuf_get_addr();
 
-	uint16_t num_paritybytes = (iLen-1)/8 + 1;	// number of valid paritybytes in *parity
+	uint32_t num_paritybytes = (iLen-1)/8 + 1;	// number of valid paritybytes in *parity
-	uint16_t duration = timestamp_end - timestamp_start;
+	uint32_t duration = timestamp_end - timestamp_start;
 
 	// Return when trace is full
 	uint16_t max_traceLen = BigBuf_max_traceLen();
@@ -200,19 +200,23 @@ bool RAMFUNC LogTrace(const uint8_t *btBytes, uint16_t iLen, uint32_t timestamp_
 
 	// data bytes
 	if (btBytes != NULL && iLen != 0) {
-		memcpy(trace + traceLen, btBytes, iLen);
+		for (int i = 0; i < iLen; i++) {
+			trace[traceLen++] = *btBytes++;
+		}
 	}
-	traceLen += iLen;
 
 	// parity bytes
 	if (num_paritybytes != 0) {
 		if (parity != NULL) {
-			memcpy(trace + traceLen, parity, num_paritybytes);
+			for (int i = 0; i < num_paritybytes; i++) {
+				trace[traceLen++] = *parity++;
+			}
 		} else {
-			memset(trace + traceLen, 0x00, num_paritybytes);
+			for (int i = 0; i < num_paritybytes; i++) {
+				trace[traceLen++] = 0x00;
+			}
 		}
 	}
-	traceLen += num_paritybytes;
 
 	return true;
 }
@@ -259,8 +263,9 @@ int LogTraceHitag(const uint8_t * btBytes, int iBits, int iSamples, uint32_t dwP
 	trace[traceLen++] = ((dwParity >> 24) & 0xff);
 	trace[traceLen++] = iBits;
 
-	memcpy(trace + traceLen, btBytes, iLen);
+	for (int i = 0; i < iLen; i++) {
-	traceLen += iLen;
+		trace[traceLen++] = *btBytes++;
+	}
 
 	return true;
 }

armsrc/appmain.c

@@ -24,6 +24,7 @@
 #include "legicrfsim.h"
 #include "hitag2.h"
 #include "hitagS.h"
+#include "iso15693.h"
 #include "lfsampling.h"
 #include "BigBuf.h"
 #include "mifareutil.h"
@@ -1115,8 +1116,9 @@ void UsbPacketReceived(uint8_t *packet, int len)
 		case CMD_ACQUIRE_RAW_ADC_SAMPLES_ISO_15693:
 			AcquireRawAdcSamplesIso15693();
 			break;
-		case CMD_RECORD_RAW_ADC_SAMPLES_ISO_15693:
+			
-			RecordRawAdcSamplesIso15693();
+		case CMD_SNOOP_ISO_15693:
+			SnoopIso15693();
 			break;
 			
 		case CMD_ISO_15693_COMMAND:

armsrc/apps.h

@@ -25,7 +25,6 @@
 
 extern const uint8_t OddByteParity[256];
 extern int rsamples;   // = 0;
-extern int tracing;    // = TRUE;
 extern uint8_t trigger;
 
 // This may be used (sparingly) to declare a function to be copied to
@@ -101,7 +100,6 @@ void RAMFUNC SnoopIso14443b(void);
 void SendRawCommand14443B(uint32_t, uint32_t, uint8_t, uint8_t[]);
 
 // Also used in iclass.c
-bool RAMFUNC LogTrace(const uint8_t *btBytes, uint16_t len, uint32_t timestamp_start, uint32_t timestamp_end, uint8_t *parity, bool readerToTag);
 void GetParity(const uint8_t *pbtCmd, uint16_t len, uint8_t *parity);
 
 void RAMFUNC SniffMifare(uint8_t param);
@@ -150,15 +148,6 @@ void 	OnSuccess();
 void 	OnError(uint8_t reason);
 
 
-/// iso15693.h
-void RecordRawAdcSamplesIso15693(void);
-void AcquireRawAdcSamplesIso15693(void);
-void ReaderIso15693(uint32_t parameter);	// Simulate an ISO15693 reader - greg
-void SimTagIso15693(uint32_t parameter, uint8_t *uid);	// simulate an ISO15693 tag - greg
-void BruteforceIso15693Afi(uint32_t speed); // find an AFI of a tag - atrox
-void DirectTag15693Command(uint32_t datalen,uint32_t speed, uint32_t recv, uint8_t data[]); // send arbitrary commands from CLI - atrox 
-void SetDebugIso15693(uint32_t flag);
-
 /// iclass.h
 void RAMFUNC SnoopIClass(void);
 void SimulateIClass(uint32_t arg0, uint32_t arg1, uint32_t arg2, uint8_t *datain);

armsrc/fpgaloader.h

@@ -61,6 +61,7 @@ void SetAdcMuxFor(uint32_t whichGpio);
 #define FPGA_HF_READER_RX_XCORR_848_KHZ             (1<<0)
 #define FPGA_HF_READER_RX_XCORR_SNOOP               (1<<1)
 #define FPGA_HF_READER_RX_XCORR_QUARTER_FREQ        (1<<2)
+#define FPGA_HF_READER_RX_XCORR_AMPLITUDE           (1<<3)
 // Options for the HF simulated tag, how to modulate
 #define FPGA_HF_SIMULATOR_NO_MODULATION             (0<<0)
 #define FPGA_HF_SIMULATOR_MODULATE_BPSK             (1<<0)

armsrc/iclass.c

@@ -751,12 +751,9 @@ void RAMFUNC SnoopIClass(void)
 
 			//if(!LogTrace(Uart.output,Uart.byteCnt, rsamples, Uart.parityBits,true)) break;
 			//if(!LogTrace(NULL, 0, Uart.endTime*16 - DELAY_READER_AIR2ARM_AS_SNIFFER, 0, true)) break;
-			if(tracing)	{
 			uint8_t parity[MAX_PARITY_SIZE];
 			GetParity(Uart.output, Uart.byteCnt, parity);
 			LogTrace(Uart.output,Uart.byteCnt, time_start, time_stop, parity, true);
-			}
-
 
 			/* And ready to receive another command. */
 		    Uart.state = STATE_UNSYNCD;
@@ -779,11 +776,9 @@ void RAMFUNC SnoopIClass(void)
 			rsamples = samples - Demod.samples;
 		    LED_B_ON();
 
-			if(tracing)	{
 			uint8_t parity[MAX_PARITY_SIZE];
 			GetParity(Demod.output, Demod.len, parity);
 			LogTrace(Demod.output, Demod.len, time_start, time_stop, parity, false);
-			}
 
 		    // And ready to receive another response.
 		    memset(&Demod, 0, sizeof(Demod));
@@ -1322,7 +1317,6 @@ int doIClassSimulation( int simulationMode, uint8_t *reader_mac_buf)
 			t2r_time = GetCountSspClk();
 		}
 
-		if (tracing) {
 		uint8_t parity[MAX_PARITY_SIZE];
 		GetParity(receivedCmd, len, parity);
 		LogTrace(receivedCmd,len, (r2t_time-time_0)<< 4, (r2t_time-time_0) << 4, parity, true);
@@ -1331,12 +1325,10 @@ int doIClassSimulation( int simulationMode, uint8_t *reader_mac_buf)
 			GetParity(trace_data, trace_data_size, parity);
 			LogTrace(trace_data, trace_data_size, (t2r_time-time_0) << 4, (t2r_time-time_0) << 4, parity, false);
 		}
-			if(!tracing) {
+		if(!get_tracing()) {
 			DbpString("Trace full");
 			//break;
 		}
-
-		}
 	}
 
 	//Dbprintf("%x", cmdsRecvd);
@@ -1509,11 +1501,9 @@ void ReaderTransmitIClass(uint8_t* frame, int len)
 		LED_A_ON();
 
 	// Store reader command in buffer
-	if (tracing) {
 	uint8_t par[MAX_PARITY_SIZE];
 	GetParity(frame, len, par);
 	LogTrace(frame, len, rsamples, rsamples, par, true);
-	}
 }
 
 //-----------------------------------------------------------------------------
@@ -1569,11 +1559,9 @@ int ReaderReceiveIClass(uint8_t* receivedAnswer)
   int samples = 0;
   if (!GetIClassAnswer(receivedAnswer,160,&samples,0)) return false;
   rsamples += samples;
-  if (tracing) {
   uint8_t parity[MAX_PARITY_SIZE];
   GetParity(receivedAnswer, Demod.len, parity);
   LogTrace(receivedAnswer,Demod.len,rsamples,rsamples,parity,false);
-  }
   if(samples == 0) return false;
   return Demod.len;
 }
@@ -1715,7 +1703,7 @@ void ReaderIClass(uint8_t arg0) {
 		// if only looking for one card try 2 times if we missed it the first time
 		if (try_once && tryCnt > 2) break; 
 		tryCnt++;
-		if(!tracing) {
+		if(!get_tracing()) {
 			DbpString("Trace full");
 			break;
 		}
@@ -1828,7 +1816,7 @@ void ReaderIClass_Replay(uint8_t arg0, uint8_t *MAC) {
 	
 		WDT_HIT();
 
-		if(!tracing) {
+		if(!get_tracing()) {
 			DbpString("Trace full");
 			break;
 		}

armsrc/iso14443a.c

@@ -1220,7 +1220,7 @@ void SimulateIso14443aTag(int tagType, int uid_1st, int uid_2nd, byte_t* data)
 			EmSendPrecompiledCmd(p_response);
 		}
 		
-		if (!tracing) {
+		if (!get_tracing()) {
 			Dbprintf("Trace Full. Simulation stopped.");
 			break;
 		}
@@ -1619,9 +1619,7 @@ void ReaderTransmitBitsPar(uint8_t* frame, uint16_t bits, uint8_t *par, uint32_t
 		LED_A_ON();
   
 	// Log reader command in trace buffer
-	if (tracing) {
 	LogTrace(frame, nbytes(bits), LastTimeProxToAirStart*16 + DELAY_ARM2AIR_AS_READER, (LastTimeProxToAirStart + LastProxToAirDuration)*16 + DELAY_ARM2AIR_AS_READER, par, true);
-	}
 }
 
 
@@ -1652,9 +1650,7 @@ void ReaderTransmit(uint8_t* frame, uint16_t len, uint32_t *timing)
 static int ReaderReceiveOffset(uint8_t* receivedAnswer, uint16_t offset, uint8_t *parity)
 {
 	if (!GetIso14443aAnswerFromTag(receivedAnswer, parity, offset)) return false;
-	if (tracing) {
 	LogTrace(receivedAnswer, Demod.len, Demod.startTime*16 - DELAY_AIR2ARM_AS_READER, Demod.endTime*16 - DELAY_AIR2ARM_AS_READER, parity, false);
-	}
 	return Demod.len;
 }
 
@@ -1662,9 +1658,7 @@ static int ReaderReceiveOffset(uint8_t* receivedAnswer, uint16_t offset, uint8_t
 int ReaderReceive(uint8_t *receivedAnswer, uint8_t *parity)
 {
 	if (!GetIso14443aAnswerFromTag(receivedAnswer, parity, 0)) return false;
-	if (tracing) {
 	LogTrace(receivedAnswer, Demod.len, Demod.startTime*16 - DELAY_AIR2ARM_AS_READER, Demod.endTime*16 - DELAY_AIR2ARM_AS_READER, parity, false);
-	}
 	return Demod.len;
 }
 

armsrc/iso14443b.c

@@ -386,10 +386,7 @@ void SimulateIso14443bTag(void)
 			break;
 		}
 
-		if (tracing) {
+		LogTrace(receivedCmd, len, 0, 0, NULL, true);
-			uint8_t parity[MAX_PARITY_SIZE];
-			LogTrace(receivedCmd, len, 0, 0, parity, true);
-		}
 
 		// Good, look at the command now.
 		if ( (len == sizeof(cmd1) && memcmp(receivedCmd, cmd1, len) == 0)
@@ -463,10 +460,7 @@ void SimulateIso14443bTag(void)
 		}
 
 		// trace the response:
-		if (tracing) {
+		LogTrace(resp, respLen, 0, 0, NULL, false);
-			uint8_t parity[MAX_PARITY_SIZE];
-			LogTrace(resp, respLen, 0, 0, parity, false);
-		}
 
 	}
 }
@@ -763,9 +757,8 @@ static void GetSamplesFor14443bDemod(int n, bool quiet)
 
 	if (!quiet) Dbprintf("max behindby = %d, samples = %d, gotFrame = %d, Demod.len = %d, Demod.sumI = %d, Demod.sumQ = %d", maxBehindBy, samples, gotFrame, Demod.len, Demod.sumI, Demod.sumQ);
 	//Tracing
-	if (tracing && Demod.len > 0) {
+	if (Demod.len > 0) {
-		uint8_t parity[MAX_PARITY_SIZE];
+		LogTrace(Demod.output, Demod.len, 0, 0, NULL, false);
-		LogTrace(Demod.output, Demod.len, 0, 0, parity, false);
 	}
 }
 
@@ -858,10 +851,7 @@ static void CodeAndTransmit14443bAsReader(const uint8_t *cmd, int len)
 {
 	CodeIso14443bAsReader(cmd, len);
 	TransmitFor14443b();
-	if (tracing) {
+	LogTrace(cmd,len, 0, 0, NULL, true);
-		uint8_t parity[MAX_PARITY_SIZE];
-		LogTrace(cmd,len, 0, 0, parity, true);
-	}
 }
 
 /* Sends an APDU to the tag
@@ -1153,7 +1143,6 @@ void RAMFUNC SnoopIso14443b(void)
 	upTo = dmaBuf;
 	lastRxCounter = ISO14443B_DMA_BUFFER_SIZE;
 	FpgaSetupSscDma((uint8_t*) dmaBuf, ISO14443B_DMA_BUFFER_SIZE);
-	uint8_t parity[MAX_PARITY_SIZE];
 
 	bool TagIsActive = false;
 	bool ReaderIsActive = false;
@@ -1198,9 +1187,7 @@ void RAMFUNC SnoopIso14443b(void)
 		if (!TagIsActive) {							// no need to try decoding reader data if the tag is sending
 			if(Handle14443bUartBit(ci & 0x01)) {
 				triggered = true;
-				if(tracing) {
+				LogTrace(Uart.output, Uart.byteCnt, samples, samples, NULL, true);
-					LogTrace(Uart.output, Uart.byteCnt, samples, samples, parity, true);
-				}
 				/* And ready to receive another command. */
 				UartReset();
 				/* And also reset the demod code, which might have been */
@@ -1209,9 +1196,7 @@ void RAMFUNC SnoopIso14443b(void)
 			}
 			if(Handle14443bUartBit(cq & 0x01)) {
 				triggered = true;
-				if(tracing) {
+				LogTrace(Uart.output, Uart.byteCnt, samples, samples, NULL, true);
-					LogTrace(Uart.output, Uart.byteCnt, samples, samples, parity, true);
-				}
 				/* And ready to receive another command. */
 				UartReset();
 				/* And also reset the demod code, which might have been */
@@ -1223,13 +1208,8 @@ void RAMFUNC SnoopIso14443b(void)
 
 		if(!ReaderIsActive && triggered) {						// no need to try decoding tag data if the reader is sending or not yet triggered
 			if(Handle14443bSamplesDemod(ci/2, cq/2)) {
-
 				//Use samples as a time measurement
-				if(tracing)
+				LogTrace(Demod.output, Demod.len, samples, samples, NULL, false);
-				{
-					uint8_t parity[MAX_PARITY_SIZE];
-					LogTrace(Demod.output, Demod.len, samples, samples, parity, false);
-				}
 				// And ready to receive another response.
 				DemodReset();
 			}

armsrc/iso15693.h

@@ -0,0 +1,24 @@
+//-----------------------------------------------------------------------------
+// Piwi - October 2018
+//
+// This code is licensed to you under the terms of the GNU GPL, version 2 or,
+// at your option, any later version. See the LICENSE.txt file for the text of
+// the license.
+//-----------------------------------------------------------------------------
+// Routines to support ISO 15693.
+//-----------------------------------------------------------------------------
+
+#ifndef __ISO15693_H
+#define __ISO15693_H
+
+#include <stdint.h>
+
+void SnoopIso15693(void);
+void AcquireRawAdcSamplesIso15693(void);
+void ReaderIso15693(uint32_t parameter);
+void SimTagIso15693(uint32_t parameter, uint8_t *uid);
+void BruteforceIso15693Afi(uint32_t speed);
+void DirectTag15693Command(uint32_t datalen,uint32_t speed, uint32_t recv, uint8_t data[]); 
+void SetDebugIso15693(uint32_t flag);
+
+#endif

client/cmdhf.c

@@ -264,7 +264,7 @@ uint16_t printTraceLine(uint16_t tracepos, uint16_t traceLen, uint8_t *trace, ui
 
 		uint8_t parityBits = parityBytes[j>>3];
 		if (protocol != ISO_14443B && (isResponse || protocol == ISO_14443A) && (oddparity8(frame[j]) != ((parityBits >> (7-(j&0x0007))) & 0x01))) {
-			snprintf(line[j/16]+(( j % 16) * 4),110, "%02x! ", frame[j]);
+			snprintf(line[j/16]+(( j % 16) * 4), 110, " %02x!", frame[j]);
 		} else {
 			snprintf(line[j/16]+(( j % 16) * 4), 110, " %02x ", frame[j]);
 		}
@@ -281,14 +281,11 @@ uint16_t printTraceLine(uint16_t tracepos, uint16_t traceLen, uint8_t *trace, ui
 		}
 	}
 
-	if(data_len == 0)
+	if (data_len == 0) {
-	{
+		sprintf(line[0]," <empty trace - possible error>");
-		if(data_len == 0){
-			sprintf(line[0],"<empty trace - possible error>");
 	}
-	}
-	//--- Draw the CRC column
 
+	//--- Draw the CRC column
 	char *crc = (crcStatus == 0 ? "!crc" : (crcStatus == 1 ? " ok " : "    "));
 
 	EndOfTransmissionTimestamp = timestamp + duration;

client/cmdhf15.c

@@ -38,15 +38,54 @@
 #include "protocols.h"
 #include "cmdmain.h"
 
-#define FrameSOF              Iso15693FrameSOF
-#define Logic0						Iso15693Logic0
-#define Logic1						Iso15693Logic1
-#define FrameEOF					Iso15693FrameEOF
-
 #define Crc(data,datalen)     Iso15693Crc(data,datalen)
 #define AddCrc(data,datalen)  Iso15693AddCrc(data,datalen)
 #define sprintUID(target,uid)	Iso15693sprintUID(target,uid)
 
+// SOF defined as
+// 1) Unmodulated time of 56.64us
+// 2) 24 pulses of 423.75khz
+// 3) logic '1' (unmodulated for 18.88us followed by 8 pulses of 423.75khz)
+
+static const int Iso15693FrameSOF[] = {
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	 1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
+	 1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
+	-1, -1, -1, -1,
+	-1, -1, -1, -1,
+	 1,  1,  1,  1,
+	 1,  1,  1,  1
+};
+static const int Iso15693Logic0[] = {
+	 1,  1,  1,  1,
+	 1,  1,  1,  1,
+	-1, -1, -1, -1,
+	-1, -1, -1, -1
+};
+static const int Iso15693Logic1[] = {
+	-1, -1, -1, -1,
+	-1, -1, -1, -1,
+	 1,  1,  1,  1,
+	 1,  1,  1,  1
+};
+
+// EOF defined as
+// 1) logic '0' (8 pulses of 423.75khz followed by unmodulated for 18.88us)
+// 2) 24 pulses of 423.75khz
+// 3) Unmodulated time of 56.64us
+
+static const int Iso15693FrameEOF[] = {
+	 1,  1,  1,  1,
+	 1,  1,  1,  1,
+	-1, -1, -1, -1,
+	-1, -1, -1, -1,
+	 1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
+	 1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+	-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1
+};
+
 // structure and database for uid -> tagtype lookups 
 typedef struct { 
 	uint64_t uid;
@@ -293,8 +332,8 @@ int CmdHF15Demod(const char *Cmd)
 	// First, correlate for SOF
 	for (i = 0; i < 200; i++) {
 		int corr = 0;
-		for (j = 0; j < arraylen(FrameSOF); j += skip) {
+		for (j = 0; j < arraylen(Iso15693FrameSOF); j += skip) {
-			corr += FrameSOF[j] * GraphBuffer[i + (j / skip)];
+			corr += Iso15693FrameSOF[j] * GraphBuffer[i + (j / skip)];
 		}
 		if (corr > max) {
 			max = corr;
@@ -302,28 +341,28 @@ int CmdHF15Demod(const char *Cmd)
 		}
 	}
 	PrintAndLog("SOF at %d, correlation %d", maxPos,
-		max / (arraylen(FrameSOF) / skip));
+		max / (arraylen(Iso15693FrameSOF) / skip));
 	
-	i = maxPos + arraylen(FrameSOF) / skip;
+	i = maxPos + arraylen(Iso15693FrameSOF) / skip;
 	int k = 0;
 	uint8_t outBuf[20];
 	memset(outBuf, 0, sizeof(outBuf));
 	uint8_t mask = 0x01;
 	for (;;) {
 			int corr0 = 0, corr00 = 0, corr01 = 0, corr1 = 0, corrEOF = 0;
-			for(j = 0; j < arraylen(Logic0); j += skip) {
+			for(j = 0; j < arraylen(Iso15693Logic0); j += skip) {
-				corr0 += Logic0[j]*GraphBuffer[i+(j/skip)];
+				corr0 += Iso15693Logic0[j]*GraphBuffer[i+(j/skip)];
 			}
 			corr01 = corr00 = corr0;
-			for(j = 0; j < arraylen(Logic0); j += skip) {
+			for(j = 0; j < arraylen(Iso15693Logic0); j += skip) {
-				corr00 += Logic0[j]*GraphBuffer[i+arraylen(Logic0)/skip+(j/skip)];
+				corr00 += Iso15693Logic0[j]*GraphBuffer[i+arraylen(Iso15693Logic0)/skip+(j/skip)];
-				corr01 += Logic1[j]*GraphBuffer[i+arraylen(Logic0)/skip+(j/skip)];
+				corr01 += Iso15693Logic1[j]*GraphBuffer[i+arraylen(Iso15693Logic0)/skip+(j/skip)];
 			}
-			for(j = 0; j < arraylen(Logic1); j += skip) {
+			for(j = 0; j < arraylen(Iso15693Logic1); j += skip) {
-				corr1 += Logic1[j]*GraphBuffer[i+(j/skip)];
+				corr1 += Iso15693Logic1[j]*GraphBuffer[i+(j/skip)];
 			}
-			for(j = 0; j < arraylen(FrameEOF); j += skip) {
+			for(j = 0; j < arraylen(Iso15693FrameEOF); j += skip) {
-				corrEOF += FrameEOF[j]*GraphBuffer[i+(j/skip)];
+				corrEOF += Iso15693FrameEOF[j]*GraphBuffer[i+(j/skip)];
 			}
 			// Even things out by the length of the target waveform.
 			corr00 *= 2;
@@ -335,17 +374,17 @@ int CmdHF15Demod(const char *Cmd)
 				PrintAndLog("EOF at %d", i);
 				break;
 		} else if (corr1 > corr0) {
-			i += arraylen(Logic1) / skip;
+			i += arraylen(Iso15693Logic1) / skip;
 			outBuf[k] |= mask;
 		} else {
-			i += arraylen(Logic0) / skip;
+			i += arraylen(Iso15693Logic0) / skip;
 		}
 		mask <<= 1;
 		if (mask == 0) {
 			k++;
 			mask = 0x01;
 		}
-		if ((i + (int)arraylen(FrameEOF)) >= GraphTraceLen) {
+		if ((i + (int)arraylen(Iso15693FrameEOF)) >= GraphTraceLen) {
 			PrintAndLog("ran off end!");
 			break;
 		}
@@ -374,10 +413,9 @@ int CmdHF15Read(const char *Cmd)
 }
 
 // Record Activity without enabling carrier
-// TODO: currently it DOES enable the carrier
+int CmdHF15Snoop(const char *Cmd)
-int CmdHF15Record(const char *Cmd)
 {
-	UsbCommand c = {CMD_RECORD_RAW_ADC_SAMPLES_ISO_15693};
+	UsbCommand c = {CMD_SNOOP_ISO_15693};
 	SendCommand(&c);
 	return 0;
 }
@@ -514,7 +552,7 @@ static command_t CommandTable15[] =
 	{"help",    CmdHF15Help,    1, "This help"},
 	{"demod",   CmdHF15Demod,   1, "Demodulate ISO15693 from tag"},
 	{"read",    CmdHF15Read,    0, "Read HF tag (ISO 15693)"},
-	{"record",  CmdHF15Record,  0, "Record Samples (ISO 15693)"}, // atrox
+	{"snoop",   CmdHF15Snoop,   0, "Eavesdrop ISO 15693 communications"},
 	{"reader",  CmdHF15Reader,  0, "Act like an ISO15693 reader"},
 	{"sim",     CmdHF15Sim,     0, "Fake an ISO15693 tag"},
 	{"cmd",     CmdHF15Cmd,     0, "Send direct commands to ISO15693 tag"},

common/iso15693tools.h

@@ -14,57 +14,4 @@ int Iso15693AddCrc(uint8_t *req, int n);
 char* Iso15693sprintUID(char *target,uint8_t *uid);
 unsigned short iclass_crc16(char *data_p, unsigned short length);
 
-//-----------------------------------------------------------------------------
-// Map a sequence of octets (~layer 2 command) into the set of bits to feed
-// to the FPGA, to transmit that command to the tag.
-// Mode: highspeed && one subcarrier (ASK)
-//-----------------------------------------------------------------------------
-
-	// The sampling rate is 106.353 ksps/s, for T = 18.8 us
-
-	// SOF defined as
-	// 1) Unmodulated time of 56.64us
-	// 2) 24 pulses of 423.75khz
-	// 3) logic '1' (unmodulated for 18.88us followed by 8 pulses of 423.75khz)
-
-	static const int Iso15693FrameSOF[] = {
-		-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-		-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-		 1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
-		 1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
-		-1, -1, -1, -1,
-		-1, -1, -1, -1,
-		 1,  1,  1,  1,
-		 1,  1,  1,  1
-	};
-	static const int Iso15693Logic0[] = {
-		 1,  1,  1,  1,
-		 1,  1,  1,  1,
-		-1, -1, -1, -1,
-		-1, -1, -1, -1
-	};
-	static const int Iso15693Logic1[] = {
-		-1, -1, -1, -1,
-		-1, -1, -1, -1,
-		 1,  1,  1,  1,
-		 1,  1,  1,  1
-	};
-
-	// EOF defined as
-	// 1) logic '0' (8 pulses of 423.75khz followed by unmodulated for 18.88us)
-	// 2) 24 pulses of 423.75khz
-	// 3) Unmodulated time of 56.64us
-
-	static const int Iso15693FrameEOF[] = {
-		 1,  1,  1,  1,
-		 1,  1,  1,  1,
-		-1, -1, -1, -1,
-		-1, -1, -1, -1,
-		 1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
-		 1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
-		-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-		-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1
-	};
-
-
 #endif

fpga/fpga_hf.v

@@ -75,6 +75,8 @@ wire hi_read_rx_xcorr_848 = conf_word[0];
 wire hi_read_rx_xcorr_snoop = conf_word[1];
 // divide subcarrier frequency by 4
 wire hi_read_rx_xcorr_quarter = conf_word[2];
+// send amplitude only instead of ci/cq pair
+wire hi_read_rx_xcorr_amplitude = conf_word[3];
 
 // For the high-frequency simulated tag: what kind of modulation to use.
 wire [2:0] hi_simulate_mod_type = conf_word[2:0];
@@ -102,7 +104,7 @@ hi_read_rx_xcorr hrxc(
 	hrxc_ssp_frame, hrxc_ssp_din, ssp_dout, hrxc_ssp_clk,
 	cross_hi, cross_lo,
 	hrxc_dbg,
-	hi_read_rx_xcorr_848, hi_read_rx_xcorr_snoop, hi_read_rx_xcorr_quarter
+	hi_read_rx_xcorr_848, hi_read_rx_xcorr_snoop, hi_read_rx_xcorr_quarter, hi_read_rx_xcorr_amplitude
 );
 
 hi_simulate hs(

fpga/hi_read_rx_xcorr.v

@@ -10,7 +10,7 @@ module hi_read_rx_xcorr(
     ssp_frame, ssp_din, ssp_dout, ssp_clk,
     cross_hi, cross_lo,
     dbg,
-    xcorr_is_848, snoop, xcorr_quarter_freq
+    xcorr_is_848, snoop, xcorr_quarter_freq, hi_read_rx_xcorr_amplitude
 );
     input pck0, ck_1356meg, ck_1356megb;
     output pwr_lo, pwr_hi, pwr_oe1, pwr_oe2, pwr_oe3, pwr_oe4;
@@ -20,7 +20,7 @@ module hi_read_rx_xcorr(
     output ssp_frame, ssp_din, ssp_clk;
     input cross_hi, cross_lo;
     output dbg;
-    input xcorr_is_848, snoop, xcorr_quarter_freq;
+    input xcorr_is_848, snoop, xcorr_quarter_freq, hi_read_rx_xcorr_amplitude;
 
 // Carrier is steady on through this, unless we're snooping.
 assign pwr_hi = ck_1356megb & (~snoop);
@@ -83,11 +83,46 @@ reg signed [13:0] corr_q_accum;
 // we will report maximum 8 significant bits
 reg signed [7:0] corr_i_out;
 reg signed [7:0] corr_q_out;
+
 // clock and frame signal for communication to ARM
 reg ssp_clk;
 reg ssp_frame;
 
 
+
+// the amplitude of the subcarrier is sqrt(ci^2 + cq^2).
+// approximate by amplitude = max(|ci|,|cq|) + 1/2*min(|ci|,|cq|)
+reg [13:0] corr_amplitude, abs_ci, abs_cq, max_ci_cq, min_ci_cq;
+
+
+always @(corr_i_accum or corr_q_accum)
+begin
+	if (corr_i_accum[13] == 1'b0)
+		abs_ci <= corr_i_accum;
+	else
+		abs_ci <= -corr_i_accum;
+	
+	if (corr_q_accum[13] == 1'b0)
+		abs_cq <= corr_q_accum;
+	else
+		abs_cq <= -corr_q_accum;
+	
+	if (abs_ci > abs_cq)
+	begin
+		max_ci_cq <= abs_ci;
+		min_ci_cq <= abs_cq;
+	end
+	else
+	begin
+		max_ci_cq <= abs_cq;
+		min_ci_cq <= abs_ci;
+	end
+
+	corr_amplitude <= max_ci_cq + min_ci_cq/2;
+
+end
+
+
 // The subcarrier reference signals
 reg subcarrier_I;
 reg subcarrier_Q;
@@ -111,17 +146,26 @@ begin
 		end
 end
 
+
 // ADC data appears on the rising edge, so sample it on the falling edge
 always @(negedge adc_clk)
 begin
     // These are the correlators: we correlate against in-phase and quadrature
-    // versions of our reference signal, and keep the (signed) result to
+    // versions of our reference signal, and keep the (signed) results or the
-    // send out later over the SSP.
+    // resulting amplitude to send out later over the SSP.
     if(corr_i_cnt == 6'd0)
     begin
         if(snoop)
         begin
-			// Send 7 most significant bits of tag signal (signed), plus 1 bit reader signal
+			if (hi_read_rx_xcorr_amplitude)
+			begin
+				// send amplitude plus 2 bits reader signal
+				corr_i_out <= corr_amplitude[13:6];
+				corr_q_out <= {corr_amplitude[5:0], after_hysteresis_prev_prev, after_hysteresis_prev};
+			end	
+			else
+			begin
+				// Send 7 most significant bits of in phase tag signal (signed), plus 1 bit reader signal
 				if (corr_i_accum[13:11] == 3'b000 || corr_i_accum[13:11] == 3'b111) 
 					corr_i_out <= {corr_i_accum[11:5], after_hysteresis_prev_prev};
 				else // truncate to maximum value
@@ -129,6 +173,7 @@ begin
 						corr_i_out <= {7'b0111111, after_hysteresis_prev_prev};
 					else
 						corr_i_out <= {7'b1000000, after_hysteresis_prev_prev};
+				// Send 7 most significant bits of quadrature phase tag signal (signed), plus 1 bit reader signal
 				if (corr_q_accum[13:11] == 3'b000 || corr_q_accum[13:11] == 3'b111) 
 					corr_q_out <= {corr_q_accum[11:5], after_hysteresis_prev};
 				else // truncate to maximum value
@@ -136,11 +181,19 @@ begin
 						corr_q_out <= {7'b0111111, after_hysteresis_prev};
 					else
 						corr_q_out <= {7'b1000000, after_hysteresis_prev};
-			after_hysteresis_prev_prev <= after_hysteresis;
+			end
         end
         else
         begin
-            // Send 8 bits of tag signal
+			if (hi_read_rx_xcorr_amplitude)
+			begin
+				// send amplitude
+				corr_i_out <= {2'b00, corr_amplitude[13:8]};
+				corr_q_out <= corr_amplitude[7:0];
+			end	
+			else
+			begin
+				// Send 8 bits of in phase tag signal
 				if (corr_i_accum[13:11] == 3'b000 || corr_i_accum[13:11] == 3'b111) 
 					corr_i_out <= corr_i_accum[11:4];
 				else // truncate to maximum value
@@ -148,6 +201,7 @@ begin
 						corr_i_out <= 8'b01111111;
 					else
 						corr_i_out <= 8'b10000000;
+				// Send 8 bits of quadrature phase tag signal
 				if (corr_q_accum[13:11] == 3'b000 || corr_q_accum[13:11] == 3'b111) 
 					corr_q_out <= corr_q_accum[11:4];
 				else // truncate to maximum value
@@ -156,6 +210,10 @@ begin
 					else
 						corr_q_out <= 8'b10000000;
 			end
+        end
+
+		// for each Q/I pair report two reader signal samples when sniffing. Store the 1st.
+		after_hysteresis_prev_prev <= after_hysteresis;
 		// Initialize next correlation. 
 		// Both I and Q reference signals are high when corr_i_nct == 0. Therefore need to accumulate.
         corr_i_accum <= $signed({1'b0,adc_d});
@@ -172,16 +230,16 @@ begin
             corr_q_accum <= corr_q_accum + $signed({1'b0,adc_d});
         else
             corr_q_accum <= corr_q_accum - $signed({1'b0,adc_d});
-
     end
 
-	// for each Q/I pair report two reader signal samples when sniffing
+	// for each Q/I pair report two reader signal samples when sniffing. Store the 2nd.
     if(corr_i_cnt == 6'd32)
         after_hysteresis_prev <= after_hysteresis;
 
     // Then the result from last time is serialized and send out to the ARM.
     // We get one report each cycle, and each report is 16 bits, so the
     // ssp_clk should be the adc_clk divided by 64/16 = 4. 
+	// ssp_clk frequency = 13,56MHz / 4 = 3.39MHz
 
     if(corr_i_cnt[1:0] == 2'b10)
         ssp_clk <= 1'b0;

include/usb_cmd.h

@@ -125,7 +125,7 @@ typedef struct{
 #define CMD_ISO_14443B_COMMAND                                            0x0305
 #define CMD_READER_ISO_15693                                              0x0310
 #define CMD_SIMTAG_ISO_15693                                              0x0311
-#define CMD_RECORD_RAW_ADC_SAMPLES_ISO_15693                              0x0312
+#define CMD_SNOOP_ISO_15693                                               0x0312
 #define CMD_ISO_15693_COMMAND                                             0x0313
 #define CMD_ISO_15693_COMMAND_DONE                                        0x0314
 #define CMD_ISO_15693_FIND_AFI                                            0x0315