[proxmark3-svn] / client / cmdlfnexwatch.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 Honeywell NexWatch tag commands
// PSK1 RF/16, RF/2, 128 bits long (known)
//-----------------------------------------------------------------------------

#include "cmdlfnexwatch.h"

#include <stdio.h>
#include <string.h>
#include <inttypes.h>
#include <stdbool.h>
#include "comms.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; 
        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);
        // 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;
}