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proxmark3/client/cmdlfti.c

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//-----------------------------------------------------------------------------
// Copyright (C) 2010 iZsh <izsh at fail0verflow.com>
//
// 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 TI commands
//-----------------------------------------------------------------------------
#include <stdio.h>
#include <stdlib.h>
#include "crc16.h"
#include "proxmark3.h"
#include "data.h"
#include "ui.h"
#include "graph.h"
#include "cmdparser.h"
#include "cmdlfti.h"
static int CmdHelp(const char *Cmd);
int CmdTIDemod(const char *Cmd)
{
/* MATLAB as follows:
f_s = 2000000; % sampling frequency
f_l = 123200; % low FSK tone
f_h = 134200; % high FSK tone
T_l = 119e-6; % low bit duration
T_h = 130e-6; % high bit duration
l = 2*pi*ones(1, floor(f_s*T_l))*(f_l/f_s);
h = 2*pi*ones(1, floor(f_s*T_h))*(f_h/f_s);
l = sign(sin(cumsum(l)));
h = sign(sin(cumsum(h)));
*/
// 2M*16/134.2k = 238
static const int LowTone[] = {
1, 1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
1, 1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
1, 1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
1, 1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
1, 1, 1, 1, 1, 1, 1, 1, -1, -1
};
// 2M*16/123.2k = 260
static const int HighTone[] = {
1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1,
1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1,
1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1,
1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1,
1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1,
1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1,
1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1,
1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1,
1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1,
1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1,
1, 1, 1, 1, 1, 1, 1, 1
};
int lowLen = sizeof(LowTone)/sizeof(int);
int highLen = sizeof(HighTone)/sizeof(int);
int convLen = (highLen>lowLen)?highLen:lowLen;
uint16_t crc;
int i, j, TagType;
int lowSum = 0, highSum = 0;;
int lowTot = 0, highTot = 0;
for (i = 0; i < GraphTraceLen - convLen; i++) {
lowSum = 0;
highSum = 0;;
for (j = 0; j < lowLen; j++) {
lowSum += LowTone[j]*GraphBuffer[i+j];
}
for (j = 0; j < highLen; j++) {
highSum += HighTone[j]*GraphBuffer[i+j];
}
lowSum = abs((100*lowSum) / lowLen);
highSum = abs((100*highSum) / highLen);
lowSum = (lowSum<0)?-lowSum:lowSum;
highSum = (highSum<0)?-highSum:highSum;
GraphBuffer[i] = (highSum << 16) | lowSum;
}
for (i = 0; i < GraphTraceLen - convLen - 16; i++) {
lowTot = 0;
highTot = 0;
// 16 and 15 are f_s divided by f_l and f_h, rounded
for (j = 0; j < 16; j++) {
lowTot += (GraphBuffer[i+j] & 0xffff);
}
for (j = 0; j < 15; j++) {
highTot += (GraphBuffer[i+j] >> 16);
}
GraphBuffer[i] = lowTot - highTot;
}
GraphTraceLen -= (convLen + 16);
RepaintGraphWindow();
// TI tag data format is 16 prebits, 8 start bits, 64 data bits,
// 16 crc CCITT bits, 8 stop bits, 15 end bits
// the 16 prebits are always low
// the 8 start and stop bits of a tag must match
// the start/stop prebits of a ro tag are 01111110
// the start/stop prebits of a rw tag are 11111110
// the 15 end bits of a ro tag are all low
// the 15 end bits of a rw tag match bits 15-1 of the data bits
// Okay, so now we have unsliced soft decisions;
// find bit-sync, and then get some bits.
// look for 17 low bits followed by 6 highs (common pattern for ro and rw tags)
int max = 0, maxPos = 0;
for (i = 0; i < 6000; i++) {
int j;
int dec = 0;
// searching 17 consecutive lows
for (j = 0; j < 17*lowLen; j++) {
dec -= GraphBuffer[i+j];
}
// searching 7 consecutive highs
for (; j < 17*lowLen + 6*highLen; j++) {
dec += GraphBuffer[i+j];
}
if (dec > max) {
max = dec;
maxPos = i;
}
}
// place a marker in the buffer to visually aid location
// of the start of sync
GraphBuffer[maxPos] = 800;
GraphBuffer[maxPos+1] = -800;
// advance pointer to start of actual data stream (after 16 pre and 8 start bits)
maxPos += 17*lowLen;
maxPos += 6*highLen;
// place a marker in the buffer to visually aid location
// of the end of sync
GraphBuffer[maxPos] = 800;
GraphBuffer[maxPos+1] = -800;
PrintAndLog("actual data bits start at sample %d", maxPos);
PrintAndLog("length %d/%d", highLen, lowLen);
uint8_t bits[1+64+16+8+16];
bits[sizeof(bits)-1] = '\0';
uint32_t shift3 = 0x7e000000, shift2 = 0, shift1 = 0, shift0 = 0;
for (i = 0; i < arraylen(bits)-1; i++) {
int high = 0;
int low = 0;
int j;
for (j = 0; j < lowLen; j++) {
low -= GraphBuffer[maxPos+j];
}
for (j = 0; j < highLen; j++) {
high += GraphBuffer[maxPos+j];
}
if (high > low) {
bits[i] = '1';
maxPos += highLen;
// bitstream arrives lsb first so shift right
shift3 |= (1<<31);
} else {
bits[i] = '.';
maxPos += lowLen;
}
// 128 bit right shift register
shift0 = (shift0>>1) | (shift1 << 31);
shift1 = (shift1>>1) | (shift2 << 31);
shift2 = (shift2>>1) | (shift3 << 31);
shift3 >>= 1;
// place a marker in the buffer between bits to visually aid location
GraphBuffer[maxPos] = 800;
GraphBuffer[maxPos+1] = -800;
}
PrintAndLog("Info: raw tag bits = %s", bits);
TagType = (shift3>>8)&0xff;
if ( TagType != ((shift0>>16)&0xff) ) {
PrintAndLog("Error: start and stop bits do not match!");
return 0;
}
else if (TagType == 0x7e) {
PrintAndLog("Info: Readonly TI tag detected.");
return 0;
}
else if (TagType == 0xfe) {
PrintAndLog("Info: Rewriteable TI tag detected.");
// put 64 bit data into shift1 and shift0
shift0 = (shift0>>24) | (shift1 << 8);
shift1 = (shift1>>24) | (shift2 << 8);
// align 16 bit crc into lower half of shift2
shift2 = ((shift2>>24) | (shift3 << 8)) & 0x0ffff;
// align 16 bit "end bits" or "ident" into lower half of shift3
shift3 >>= 16;
// only 15 bits compare, last bit of ident is not valid
if ( (shift3^shift0)&0x7fff ) {
PrintAndLog("Error: Ident mismatch!");
}
// WARNING the order of the bytes in which we calc crc below needs checking
// i'm 99% sure the crc algorithm is correct, but it may need to eat the
// bytes in reverse or something
// calculate CRC
crc=0;
crc = update_crc16(crc, (shift0)&0xff);
crc = update_crc16(crc, (shift0>>8)&0xff);
crc = update_crc16(crc, (shift0>>16)&0xff);
crc = update_crc16(crc, (shift0>>24)&0xff);
crc = update_crc16(crc, (shift1)&0xff);
crc = update_crc16(crc, (shift1>>8)&0xff);
crc = update_crc16(crc, (shift1>>16)&0xff);
crc = update_crc16(crc, (shift1>>24)&0xff);
PrintAndLog("Info: Tag data = %08X%08X", shift1, shift0);
if (crc != (shift2&0xffff)) {
PrintAndLog("Error: CRC mismatch, calculated %04X, got ^04X", crc, shift2&0xffff);
} else {
PrintAndLog("Info: CRC %04X is good", crc);
}
}
else {
PrintAndLog("Unknown tag type.");
return 0;
}
return 0;
}
// read a TI tag and return its ID
int CmdTIRead(const char *Cmd)
{
UsbCommand c = {CMD_READ_TI_TYPE};
SendCommand(&c);
return 0;
}
// write new data to a r/w TI tag
int CmdTIWrite(const char *Cmd)
{
UsbCommand c = {CMD_WRITE_TI_TYPE};
int res = 0;
res = sscanf(Cmd, "%012"llx" %012"llx" %012"llx"", &c.arg[0], &c.arg[1], &c.arg[2]);
if (res == 2) c.arg[2]=0;
if (res < 2)
PrintAndLog("Please specify the data as two hex strings, optionally the CRC as a third");
else
SendCommand(&c);
return 0;
}
static command_t CommandTable[] =
{
{"help", CmdHelp, 1, "This help"},
{"demod", CmdTIDemod, 1, "Demodulate raw bits for TI-type LF tag"},
{"read", CmdTIRead, 0, "Read and decode a TI 134 kHz tag"},
{"write", CmdTIWrite, 0, "Write new data to a r/w TI 134 kHz tag"},
{NULL, NULL, 0, NULL}
};
int CmdLFTI(const char *Cmd)
{
CmdsParse(CommandTable, Cmd);
return 0;
}
int CmdHelp(const char *Cmd)
{
CmdsHelp(CommandTable);
return 0;
}
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