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[proxmark3-svn] / client / cmdlfpac.c

//-----------------------------------------------------------------------------
//
// 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 Stanley/PAC tag commands
// NRZ, RF/32, 128 bits long (unknown cs)
//-----------------------------------------------------------------------------
#include "cmdlfpac.h"
#include <string.h>
#include <inttypes.h>
#include "proxmark3.h"
#include "ui.h"
#include "util.h"
#include "graph.h"
#include "cmdparser.h"
#include "cmddata.h"
#include "cmdmain.h"
#include "cmdlf.h"
#include "lfdemod.h"    // preamble test

static int CmdHelp(const char *Cmd);

// by marshmellow
// find PAC preamble in already demoded data
int PacFind(uint8_t *dest, size_t *size) {
        if (*size < 128) return -1; //make sure buffer has data
        size_t startIdx = 0;
        uint8_t preamble[] = {1,1,1,1,1,1,1,1,0,0,1,0,0,0,0,0,0,1,0};
        if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
                return -2; //preamble not found
        if (*size != 128) return -3; //wrong demoded size
        //return start position
        return (int)startIdx;
}

//see NRZDemod for what args are accepted
int CmdPacDemod(const char *Cmd) {

        //NRZ
        if (!NRZrawDemod(Cmd, false)) {
                if (g_debugMode) PrintAndLog("DEBUG: Error - PAC: NRZ Demod failed");
                return 0;
        }
        size_t size = DemodBufferLen;
        int ans = PacFind(DemodBuffer, &size);
        if (ans < 0) {
                if (g_debugMode) {
                        if (ans == -1)
                                PrintAndLog("DEBUG: Error - PAC: too few bits found");
                        else if (ans == -2)
                                PrintAndLog("DEBUG: Error - PAC: preamble not found");
                        else if (ans == -3)
                                PrintAndLog("DEBUG: Error - PAC: Size not correct: %d", size);
                        else
                                PrintAndLog("DEBUG: Error - PAC: ans: %d", ans);
                }
                return 0;
        }
        setDemodBuf(DemodBuffer, 128, ans);
        setClockGrid(g_DemodClock, g_DemodStartIdx + (ans*g_DemodClock));

        //got a good demod
        uint32_t raw1 = bytebits_to_byte(DemodBuffer   , 32);
        uint32_t raw2 = bytebits_to_byte(DemodBuffer+32, 32);
        uint32_t raw3 = bytebits_to_byte(DemodBuffer+64, 32);
        uint32_t raw4 = bytebits_to_byte(DemodBuffer+96, 32);

        // preamble     then appears to have marker bits of "10"                                                                                                                                       CS?    
        // 11111111001000000 10 01001100 10 00001101 10 00001101 10 00001101 10 00001101 10 00001101 10 00001101 10 00001101 10 00001101 10 10001100 10 100000001
        // unknown checksum 9 bits at the end
        
        PrintAndLog("PAC/Stanley Tag Found -- Raw: %08X%08X%08X%08X", raw1 ,raw2, raw3, raw4);
        PrintAndLog("\nHow the Raw ID is translated by the reader is unknown");
        return 1;
}

int CmdPacRead(const char *Cmd) {
        lf_read(true, 4096*2 + 20);
        return CmdPacDemod(Cmd);
}

static command_t CommandTable[] = {
        {"help",  CmdHelp,    1, "This help"},
        {"demod", CmdPacDemod,1, "Attempt to read and extract tag data from the GraphBuffer"},
        {"read",  CmdPacRead, 0, "Attempt to read and extract tag data from the antenna"},
        {NULL, NULL, 0, NULL}
};

int CmdLFPac(const char *Cmd) {
        clearCommandBuffer();
        CmdsParse(CommandTable, Cmd);
        return 0;
}

int CmdHelp(const char *Cmd) {
        CmdsHelp(CommandTable);
        return 0;
}