hardnested: reduce disk space for tables (by > 700MBytes) and other minor changes

[proxmark3-svn] / client / cmdlfgproxii.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 G Prox II tag commands
// Biphase, rf/ , 96 bits  (unknown key calc + some bits)
//-----------------------------------------------------------------------------
#include <stdio.h>
#include <string.h>
#include <inttypes.h>
#include "cmdlfgproxii.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"
static int CmdHelp(const char *Cmd);

//by marshmellow
//attempts to demodulate and identify a G_Prox_II verex/chubb card
//WARNING: if it fails during some points it will destroy the DemodBuffer data
// but will leave the GraphBuffer intact.
//if successful it will push askraw data back to demod buffer ready for emulation
int CmdG_Prox_II_Demod(const char *Cmd)
{
        if (!ASKbiphaseDemod(Cmd, false)){
                if (g_debugMode) PrintAndLog("Error gProxII: ASKbiphaseDemod failed 1st try");
                return 0;
        }
        size_t size = DemodBufferLen;
        //call lfdemod.c demod for gProxII
        int ans = gProxII_Demod(DemodBuffer, &size);
        if (ans < 0){
                if (g_debugMode) PrintAndLog("Error gProxII_Demod");
                return 0;
        }
        //got a good demod of 96 bits
        uint8_t ByteStream[8] = {0x00};
        uint8_t xorKey=0;
        size_t startIdx = ans + 6; //start after 6 bit preamble

        uint8_t bits_no_spacer[90];
        //so as to not mess with raw DemodBuffer copy to a new sample array
        memcpy(bits_no_spacer, DemodBuffer + startIdx, 90);
        // remove the 18 (90/5=18) parity bits (down to 72 bits (96-6-18=72))
        size_t bitLen = removeParity(bits_no_spacer, 0, 5, 3, 90); //source, startloc, paritylen, ptype, length_to_run
        if (bitLen != 72) {
                if (g_debugMode) PrintAndLog("Error gProxII: spacer removal did not produce 72 bits: %u, start: %u", bitLen, startIdx);
                return 0;
        }
        // get key and then get all 8 bytes of payload decoded
        xorKey = (uint8_t)bytebits_to_byteLSBF(bits_no_spacer, 8);
        for (size_t idx = 0; idx < 8; idx++) {
                ByteStream[idx] = ((uint8_t)bytebits_to_byteLSBF(bits_no_spacer+8 + (idx*8),8)) ^ xorKey;
                if (g_debugMode) PrintAndLog("byte %u after xor: %02x", (unsigned int)idx, ByteStream[idx]);
        }
        //now ByteStream contains 8 Bytes (64 bits) of decrypted raw tag data
        // 
        uint8_t fmtLen = ByteStream[0]>>2;
        uint32_t FC = 0;
        uint32_t Card = 0;
        //get raw 96 bits to print
        uint32_t raw1 = bytebits_to_byte(DemodBuffer+ans,32);
        uint32_t raw2 = bytebits_to_byte(DemodBuffer+ans+32, 32);
        uint32_t raw3 = bytebits_to_byte(DemodBuffer+ans+64, 32);

        if (fmtLen==36){
                FC = ((ByteStream[3] & 0x7F)<<7) | (ByteStream[4]>>1);
                Card = ((ByteStream[4]&1)<<19) | (ByteStream[5]<<11) | (ByteStream[6]<<3) | (ByteStream[7]>>5);
                PrintAndLog("G-Prox-II Found: FmtLen %d, FC %u, Card %u", (int)fmtLen, FC, Card);
        } else if(fmtLen==26){
                FC = ((ByteStream[3] & 0x7F)<<1) | (ByteStream[4]>>7);
                Card = ((ByteStream[4]&0x7F)<<9) | (ByteStream[5]<<1) | (ByteStream[6]>>7);
                PrintAndLog("G-Prox-II Found: FmtLen %d, FC %u, Card %u", (int)fmtLen, FC, Card);
        } else {
                PrintAndLog("Unknown G-Prox-II Fmt Found: FmtLen %d",(int)fmtLen);
                PrintAndLog("Decoded Raw: %s", sprint_hex(ByteStream, 8)); 
        }
        PrintAndLog("Raw: %08x%08x%08x", raw1,raw2,raw3);
        setDemodBuf(DemodBuffer, 96, ans);
        setClockGrid(g_DemodClock, g_DemodStartIdx + (ans*g_DemodClock));

        return 1;
}
//by marshmellow
//see ASKDemod for what args are accepted
int CmdG_Prox_II_Read(const char *Cmd) {
        // read lf silently
        lf_read(true, 10000);
        // demod and output viking ID   
        return CmdG_Prox_II_Demod(Cmd);
}

static command_t CommandTable[] = {
        {"help",  CmdHelp,            1, "This help"},
        {"demod", CmdG_Prox_II_Demod, 1, "Demodulate a G Prox II tag from the GraphBuffer"},
        {"read",  CmdG_Prox_II_Read,  0, "Attempt to read and Extract tag data from the antenna"},
        {NULL, NULL, 0, NULL}
};

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

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