ADD 'lf nexawatch' by marshmellow42

ADD 'lf securakey'  by marshmellow42
ADD 'lf pac'  by marshmellow42
chg: parity.h got some love from pm3 master.

client/cmdlfnexwatch.c

@@ -0,0 +1,100 @@
+//-----------------------------------------------------------------------------
+//
+// 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.
+//-----------------------------------------------------------------------------
+// Low frequency Honeywell NexWatch tag commands
+// PSK1 RF/16, RF/2, 128 bits long (known)
+//-----------------------------------------------------------------------------
+#include <stdio.h>
+#include <string.h>
+#include <inttypes.h>
+#include <stdbool.h>
+#include "cmdlfnexwatch.h"
+#include "proxmark3.h"
+#include "ui.h"
+#include "util.h"
+#include "graph.h"
+#include "cmdparser.h"
+#include "cmddata.h"
+#include "cmdlf.h"
+#include "lfdemod.h"
+
+static int CmdHelp(const char *Cmd);
+
+int CmdPSKNexWatch(const char *Cmd)
+{
+	if (!PSKDemod("", false)) return 0;
+
+	uint8_t preamble[28] = {0,0,0,0,0,1,0,1,0,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
+	size_t startIdx = 0, size = DemodBufferLen;
+
+	// sanity check. 
+	if ( size < sizeof(preamble) + 100) return 0;
+
+	bool invert = false;
+	if (!preambleSearch(DemodBuffer, preamble, sizeof(preamble), &size, &startIdx)){
+		// if didn't find preamble try again inverting
+		if (!PSKDemod("1", false)) return 0;
+		
+		size = DemodBufferLen;
+		if (!preambleSearch(DemodBuffer, preamble, sizeof(preamble), &size, &startIdx)) return 0;
+		invert = true;
+	}
+	if (size != 128) return 0;
+	setDemodBuf(DemodBuffer, size, startIdx+4);
+	//setClockGrid(g_DemodClock, g_DemodStartIdx + ((startIdx+4)*g_DemodClock));
+	startIdx = 8+32; // 8 = preamble, 32 = reserved bits (always 0)
+	//get ID
+	uint32_t ID = 0;
+	for (uint8_t wordIdx=0; wordIdx<4; wordIdx++){
+		for (uint8_t idx=0; idx<8; idx++){
+			ID = (ID << 1) | DemodBuffer[startIdx+wordIdx+(idx*4)];
+		}	
+	}
+	//parity check (TBD)
+
+	//checksum check (TBD)
+
+	//output
+	PrintAndLog("NexWatch ID: %d", ID);
+	if (invert){
+		PrintAndLog("Had to Invert - probably NexKey");
+		for (uint8_t idx=0; idx<size; idx++)
+			DemodBuffer[idx] ^= 1;
+	} 
+
+	CmdPrintDemodBuff("x");
+	return 1;
+}
+
+//by marshmellow
+//see ASKDemod for what args are accepted
+int CmdNexWatchRead(const char *Cmd) {
+	// read lf silently
+	//lf_read(true, 10000);
+	
+	CmdLFRead("s");
+	getSamples("10000",TRUE);
+	
+	// demod and output viking ID	
+	return CmdPSKNexWatch(Cmd);
+}
+
+static command_t CommandTable[] = {
+	{"help",  CmdHelp,          1, "This help"},
+	{"demod", CmdPSKNexWatch,   1, "Demodulate a NexWatch tag (nexkey, quadrakey) from the GraphBuffer"},
+	{"read",  CmdNexWatchRead,  0, "Attempt to Read and Extract tag data from the antenna"},
+	{NULL, NULL, 0, NULL}
+};
+
+int CmdLFNexWatch(const char *Cmd) {
+	CmdsParse(CommandTable, Cmd);
+	return 0;
+}
+
+int CmdHelp(const char *Cmd) {
+	CmdsHelp(CommandTable);
+	return 0;
+}