cvs.zerfleddert.de Git - proxmark3-svn/blob - client/cmdlfti.c

   1 //-----------------------------------------------------------------------------
   2 // Copyright (C) 2010 iZsh <izsh at fail0verflow.com>
   3 //
   4 // This code is licensed to you under the terms of the GNU GPL, version 2 or,
   5 // at your option, any later version. See the LICENSE.txt file for the text of
   6 // the license.
   7 //-----------------------------------------------------------------------------
   8 // Low frequency TI commands
   9 //-----------------------------------------------------------------------------
  10
  11 #include <stdio.h>
  12 #include <stdlib.h>
  13 #include "crc16.h"
  14 #include "proxmark3.h"
  15 #include "data.h"
  16 #include "ui.h"
  17 #include "graph.h"
  18 #include "cmdparser.h"
  19 #include "cmdlfti.h"
  20 #include "cmdmain.h"
  21
  22 static int CmdHelp(const char *Cmd);
  23
  24 int CmdTIDemod(const char *Cmd)
  25 {
  26   /* MATLAB as follows:
  27     f_s = 2000000;  % sampling frequency
  28     f_l = 123200;   % low FSK tone
  29     f_h = 134200;   % high FSK tone
  30
  31     T_l = 119e-6;   % low bit duration
  32     T_h = 130e-6;   % high bit duration
  33
  34     l = 2*pi*ones(1, floor(f_s*T_l))*(f_l/f_s);
  35     h = 2*pi*ones(1, floor(f_s*T_h))*(f_h/f_s);
  36
  37     l = sign(sin(cumsum(l)));
  38     h = sign(sin(cumsum(h)));
  39   */
  40
  41   // 2M*16/134.2k = 238
  42   static const int LowTone[] = {
  43     1, 1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
  44     1, 1, 1, 1, 1, 1, 1, 1,    -1, -1, -1, -1, -1, -1, -1, -1,
  45     1, 1, 1, 1, 1, 1, 1, 1,    -1, -1, -1, -1, -1, -1, -1, -1,
  46     1, 1, 1, 1, 1, 1, 1, 1,    -1, -1, -1, -1, -1, -1, -1, -1,
  47     1, 1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
  48     1, 1, 1, 1, 1, 1, 1, 1,    -1, -1, -1, -1, -1, -1, -1, -1,
  49     1, 1, 1, 1, 1, 1, 1, 1,    -1, -1, -1, -1, -1, -1, -1, -1,
  50     1, 1, 1, 1, 1, 1, 1, 1,    -1, -1, -1, -1, -1, -1, -1, -1,
  51     1, 1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
  52     1, 1, 1, 1, 1, 1, 1, 1,    -1, -1, -1, -1, -1, -1, -1, -1,
  53     1, 1, 1, 1, 1, 1, 1, 1,    -1, -1, -1, -1, -1, -1, -1, -1,
  54     1, 1, 1, 1, 1, 1, 1, 1,    -1, -1, -1, -1, -1, -1, -1, -1,
  55     1, 1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
  56     1, 1, 1, 1, 1, 1, 1, 1,    -1, -1, -1, -1, -1, -1, -1, -1,
  57     1, 1, 1, 1, 1, 1, 1, 1,    -1, -1
  58   };
  59   // 2M*16/123.2k = 260
  60   static const int HighTone[] = {
  61     1, 1, 1, 1, 1, 1, 1, 1,   -1, -1, -1, -1, -1, -1, -1,
  62     1, 1, 1, 1, 1, 1, 1, 1,   -1, -1, -1, -1, -1, -1, -1,
  63     1, 1, 1, 1, 1, 1, 1,      -1, -1, -1, -1, -1, -1, -1, -1,
  64     1, 1, 1, 1, 1, 1, 1,      -1, -1, -1, -1, -1, -1, -1, -1,
  65     1, 1, 1, 1, 1, 1, 1,      -1, -1, -1, -1, -1, -1, -1, -1,
  66     1, 1, 1, 1, 1, 1, 1,      -1, -1, -1, -1, -1, -1, -1,
  67     1, 1, 1, 1, 1, 1, 1, 1,   -1, -1, -1, -1, -1, -1, -1,
  68     1, 1, 1, 1, 1, 1, 1, 1,   -1, -1, -1, -1, -1, -1, -1,
  69     1, 1, 1, 1, 1, 1, 1,      -1, -1, -1, -1, -1, -1, -1, -1,
  70     1, 1, 1, 1, 1, 1, 1,      -1, -1, -1, -1, -1, -1, -1, -1,
  71     1, 1, 1, 1, 1, 1, 1,      -1, -1, -1, -1, -1, -1, -1,
  72     1, 1, 1, 1, 1, 1, 1, 1,   -1, -1, -1, -1, -1, -1, -1,
  73     1, 1, 1, 1, 1, 1, 1, 1,   -1, -1, -1, -1, -1, -1, -1,
  74     1, 1, 1, 1, 1, 1, 1, 1,   -1, -1, -1, -1, -1, -1, -1,
  75     1, 1, 1, 1, 1, 1, 1,      -1, -1, -1, -1, -1, -1, -1, -1,
  76     1, 1, 1, 1, 1, 1, 1,      -1, -1, -1, -1, -1, -1, -1, -1,
  77     1, 1, 1, 1, 1, 1, 1,      -1, -1, -1, -1, -1, -1, -1,
  78     1, 1, 1, 1, 1, 1, 1, 1
  79   };
  80         int lowLen = sizeof(LowTone)/sizeof(int);
  81         int highLen = sizeof(HighTone)/sizeof(int);
  82         int convLen = (highLen>lowLen)?highLen:lowLen;
  83         uint16_t crc;
  84         int i, j, TagType;
  85         int lowSum = 0, highSum = 0;;
  86         int lowTot = 0, highTot = 0;
  87
  88         for (i = 0; i < GraphTraceLen - convLen; i++) {
  89                 lowSum = 0;
  90                 highSum = 0;;
  91
  92                 for (j = 0; j < lowLen; j++) {
  93                         lowSum += LowTone[j]*GraphBuffer[i+j];
  94                 }
  95                 for (j = 0; j < highLen; j++) {
  96                         highSum += HighTone[j]*GraphBuffer[i+j];
  97                 }
  98                 lowSum = abs((100*lowSum) / lowLen);
  99                 highSum = abs((100*highSum) / highLen);
 100                 lowSum = (lowSum<0)?-lowSum:lowSum;
 101                 highSum = (highSum<0)?-highSum:highSum;
 102
 103                 GraphBuffer[i] = (highSum << 16) | lowSum;
 104         }
 105
 106         for (i = 0; i < GraphTraceLen - convLen - 16; i++) {
 107                 lowTot = 0;
 108                 highTot = 0;
 109                 // 16 and 15 are f_s divided by f_l and f_h, rounded
 110                 for (j = 0; j < 16; j++) {
 111                         lowTot += (GraphBuffer[i+j] & 0xffff);
 112                 }
 113                 for (j = 0; j < 15; j++) {
 114                         highTot += (GraphBuffer[i+j] >> 16);
 115                 }
 116                 GraphBuffer[i] = lowTot - highTot;
 117         }
 118
 119         GraphTraceLen -= (convLen + 16);
 120
 121         RepaintGraphWindow();
 122
 123         // TI tag data format is 16 prebits, 8 start bits, 64 data bits,
 124         // 16 crc CCITT bits, 8 stop bits, 15 end bits
 125
 126         // the 16 prebits are always low
 127         // the 8 start and stop bits of a tag must match
 128         // the start/stop prebits of a ro tag are 01111110
 129         // the start/stop prebits of a rw tag are 11111110
 130         // the 15 end bits of a ro tag are all low
 131         // the 15 end bits of a rw tag match bits 15-1 of the data bits
 132
 133         // Okay, so now we have unsliced soft decisions;
 134         // find bit-sync, and then get some bits.
 135         // look for 17 low bits followed by 6 highs (common pattern for ro and rw tags)
 136         int max = 0, maxPos = 0;
 137         for (i = 0; i < 6000; i++) {
 138                 int j;
 139                 int dec = 0;
 140                 // searching 17 consecutive lows
 141                 for (j = 0; j < 17*lowLen; j++) {
 142                         dec -= GraphBuffer[i+j];
 143                 }
 144                 // searching 7 consecutive highs
 145                 for (; j < 17*lowLen + 6*highLen; j++) {
 146                         dec += GraphBuffer[i+j];
 147                 }
 148                 if (dec > max) {
 149                         max = dec;
 150                         maxPos = i;
 151                 }
 152         }
 153
 154         // place a marker in the buffer to visually aid location
 155         // of the start of sync
 156         GraphBuffer[maxPos] = 800;
 157         GraphBuffer[maxPos+1] = -800;
 158
 159         // advance pointer to start of actual data stream (after 16 pre and 8 start bits)
 160         maxPos += 17*lowLen;
 161         maxPos += 6*highLen;
 162
 163         // place a marker in the buffer to visually aid location
 164         // of the end of sync
 165         GraphBuffer[maxPos] = 800;
 166         GraphBuffer[maxPos+1] = -800;
 167
 168         PrintAndLog("actual data bits start at sample %d", maxPos);
 169
 170         PrintAndLog("length %d/%d", highLen, lowLen);
 171
 172         uint8_t bits[1+64+16+8+16];
 173         bits[sizeof(bits)-1] = '\0';
 174
 175         uint32_t shift3 = 0x7e000000, shift2 = 0, shift1 = 0, shift0 = 0;
 176
 177         for (i = 0; i < ARRAYLEN(bits)-1; i++) {
 178                 int high = 0;
 179                 int low = 0;
 180                 int j;
 181                 for (j = 0; j < lowLen; j++) {
 182                         low -= GraphBuffer[maxPos+j];
 183                 }
 184                 for (j = 0; j < highLen; j++) {
 185                         high += GraphBuffer[maxPos+j];
 186                 }
 187
 188                 if (high > low) {
 189                         bits[i] = '1';
 190                         maxPos += highLen;
 191                         // bitstream arrives lsb first so shift right
 192                         shift3 |= (1<<31);
 193                 } else {
 194                         bits[i] = '.';
 195                         maxPos += lowLen;
 196                 }
 197
 198                 // 128 bit right shift register
 199                 shift0 = (shift0>>1) | (shift1 << 31);
 200                 shift1 = (shift1>>1) | (shift2 << 31);
 201                 shift2 = (shift2>>1) | (shift3 << 31);
 202                 shift3 >>= 1;
 203
 204                 // place a marker in the buffer between bits to visually aid location
 205                 GraphBuffer[maxPos] = 800;
 206                 GraphBuffer[maxPos+1] = -800;
 207         }
 208         PrintAndLog("Info: raw tag bits = %s", bits);
 209
 210         TagType = (shift3>>8)&0xff;
 211         if ( TagType != ((shift0>>16)&0xff) ) {
 212                 PrintAndLog("Error: start and stop bits do not match!");
 213                 return 0;
 214         }
 215         else if (TagType == 0x7e) {
 216                 PrintAndLog("Info: Readonly TI tag detected.");
 217                 return 0;
 218         }
 219         else if (TagType == 0xfe) {
 220                 PrintAndLog("Info: Rewriteable TI tag detected.");
 221
 222                 // put 64 bit data into shift1 and shift0
 223                 shift0 = (shift0>>24) | (shift1 << 8);
 224                 shift1 = (shift1>>24) | (shift2 << 8);
 225
 226                 // align 16 bit crc into lower half of shift2
 227                 shift2 = ((shift2>>24) | (shift3 << 8)) & 0x0ffff;
 228
 229                 // align 16 bit "end bits" or "ident" into lower half of shift3
 230                 shift3 >>= 16;
 231
 232                 // only 15 bits compare, last bit of ident is not valid
 233                 if ( (shift3^shift0)&0x7fff ) {
 234                   PrintAndLog("Error: Ident mismatch!");
 235                 }
 236                 // WARNING the order of the bytes in which we calc crc below needs checking
 237                 // i'm 99% sure the crc algorithm is correct, but it may need to eat the
 238                 // bytes in reverse or something
 239                 // calculate CRC
 240                 crc=0;
 241                 crc = update_crc16(crc, (shift0)&0xff);
 242                 crc = update_crc16(crc, (shift0>>8)&0xff);
 243                 crc = update_crc16(crc, (shift0>>16)&0xff);
 244                 crc = update_crc16(crc, (shift0>>24)&0xff);
 245                 crc = update_crc16(crc, (shift1)&0xff);
 246                 crc = update_crc16(crc, (shift1>>8)&0xff);
 247                 crc = update_crc16(crc, (shift1>>16)&0xff);
 248                 crc = update_crc16(crc, (shift1>>24)&0xff);
 249
 250                 //crc =  crc16_ccitt(message, sizeof(message);
 251
 252                 char *crcStr = (crc == (shift2&0xffff) ) ? "Passed" : "Failed";
 253
 254                 PrintAndLog("Tag data = %08X%08X  [Crc %04X %s]", shift1, shift0, crc, crcStr );
 255
 256                 if (crc != (shift2&0xffff))
 257                         PrintAndLog("Error: CRC mismatch, calculated %04X, got ^04X", crc, shift2&0xffff);
 258
 259         }
 260         else {
 261                 PrintAndLog("Unknown tag type.");
 262         }
 263         return 0;
 264 }
 265
 266 // read a TI tag and return its ID
 267 int CmdTIRead(const char *Cmd)
 268 {
 269         UsbCommand c = {CMD_READ_TI_TYPE};
 270         clearCommandBuffer();
 271         SendCommand(&c);
 272         return 0;
 273 }
 274
 275 // write new data to a r/w TI tag
 276 int CmdTIWrite(const char *Cmd)
 277 {
 278         int res = 0;
 279         UsbCommand c = {CMD_WRITE_TI_TYPE};
 280         res = sscanf(Cmd, "%012"llx" %012"llx" %012"llx"", &c.arg[0], &c.arg[1], &c.arg[2]);
 281
 282         if (res == 2) c.arg[2]=0;
 283         if (res < 2) {
 284                 PrintAndLog("Please specify the data as two hex strings, optionally the CRC as a third");
 285                 return 1;
 286         }
 287         clearCommandBuffer();
 288         SendCommand(&c);
 289         return 0;
 290 }
 291
 292 static command_t CommandTable[] = {
 293   {"help",      CmdHelp,        1, "This help"},
 294   {"demod",     CmdTIDemod,     1, "Demodulate raw bits for TI-type LF tag"},
 295   {"read",      CmdTIRead,      0, "Read and decode a TI 134 kHz tag"},
 296   {"write",     CmdTIWrite,     0, "Write new data to a r/w TI 134 kHz tag"},
 297   {NULL, NULL, 0, NULL}
 298 };
 299
 300 int CmdLFTI(const char *Cmd){
 301         clearCommandBuffer();
 302         CmdsParse(CommandTable, Cmd);
 303         return 0;
 304 }
 305
 306 int CmdHelp(const char *Cmd){
 307         CmdsHelp(CommandTable);
 308         return 0;
 309 }