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

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