extracted download and signature verification functionality to a function in tools...

[proxmark3-svn] / client / cmdlf.c

//-----------------------------------------------------------------------------
// 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 commands
//-----------------------------------------------------------------------------

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include "proxusb.h"
#include "data.h"
#include "graph.h"
#include "ui.h"
#include "cmdparser.h"
#include "cmdmain.h"
#include "cmddata.h"
#include "cmdlf.h"
#include "cmdlfhid.h"
#include "cmdlfti.h"
#include "cmdlfem4x.h"

static int CmdHelp(const char *Cmd);

/* send a command before reading */
int CmdLFCommandRead(const char *Cmd)
{
  static char dummy[3];

  dummy[0]= ' ';

  UsbCommand c = {CMD_MOD_THEN_ACQUIRE_RAW_ADC_SAMPLES_125K};
  sscanf(Cmd, "%i %i %i %s %s", &c.arg[0], &c.arg[1], &c.arg[2], (char *) &c.d.asBytes,(char *) &dummy+1);
  // in case they specified 'h'
  strcpy((char *)&c.d.asBytes + strlen((char *)c.d.asBytes), dummy);
  SendCommand(&c);
  return 0;
}

int CmdFlexdemod(const char *Cmd)
{
  int i;
  for (i = 0; i < GraphTraceLen; ++i) {
    if (GraphBuffer[i] < 0) {
      GraphBuffer[i] = -1;
    } else {
      GraphBuffer[i] = 1;
    }
  }

#define LONG_WAIT 100
  int start;
  for (start = 0; start < GraphTraceLen - LONG_WAIT; start++) {
    int first = GraphBuffer[start];
    for (i = start; i < start + LONG_WAIT; i++) {
      if (GraphBuffer[i] != first) {
        break;
      }
    }
    if (i == (start + LONG_WAIT)) {
      break;
    }
  }
  if (start == GraphTraceLen - LONG_WAIT) {
    PrintAndLog("nothing to wait for");
    return 0;
  }

  GraphBuffer[start] = 2;
  GraphBuffer[start+1] = -2;

  uint8_t bits[64];

  int bit;
  i = start;
  for (bit = 0; bit < 64; bit++) {
    int j;
    int sum = 0;
    for (j = 0; j < 16; j++) {
      sum += GraphBuffer[i++];
    }
    if (sum > 0) {
      bits[bit] = 1;
    } else {
      bits[bit] = 0;
    }
    PrintAndLog("bit %d sum %d", bit, sum);
  }

  for (bit = 0; bit < 64; bit++) {
    int j;
    int sum = 0;
    for (j = 0; j < 16; j++) {
      sum += GraphBuffer[i++];
    }
    if (sum > 0 && bits[bit] != 1) {
      PrintAndLog("oops1 at %d", bit);
    }
    if (sum < 0 && bits[bit] != 0) {
      PrintAndLog("oops2 at %d", bit);
    }
  }

  GraphTraceLen = 32*64;
  i = 0;
  int phase = 0;
  for (bit = 0; bit < 64; bit++) {
    if (bits[bit] == 0) {
      phase = 0;
    } else {
      phase = 1;
    }
    int j;
    for (j = 0; j < 32; j++) {
      GraphBuffer[i++] = phase;
      phase = !phase;
    }
  }

  RepaintGraphWindow();
  return 0;
}

int CmdIndalaDemod(const char *Cmd)
{
  // Usage: recover 64bit UID by default, specify "224" as arg to recover a 224bit UID

  int state = -1;
  int count = 0;
  int i, j;
  // worst case with GraphTraceLen=64000 is < 4096
  // under normal conditions it's < 2048
  uint8_t rawbits[4096];
  int rawbit = 0;
  int worst = 0, worstPos = 0;
  PrintAndLog("Expecting a bit less than %d raw bits", GraphTraceLen / 32);
  for (i = 0; i < GraphTraceLen-1; i += 2) {
    count += 1;
    if ((GraphBuffer[i] > GraphBuffer[i + 1]) && (state != 1)) {
      if (state == 0) {
        for (j = 0; j <  count - 8; j += 16) {
          rawbits[rawbit++] = 0;
        }
        if ((abs(count - j)) > worst) {
          worst = abs(count - j);
          worstPos = i;
        }
      }
      state = 1;
      count = 0;
    } else if ((GraphBuffer[i] < GraphBuffer[i + 1]) && (state != 0)) {
      if (state == 1) {
        for (j = 0; j <  count - 8; j += 16) {
          rawbits[rawbit++] = 1;
        }
        if ((abs(count - j)) > worst) {
          worst = abs(count - j);
          worstPos = i;
        }
      }
      state = 0;
      count = 0;
    }
  }
  PrintAndLog("Recovered %d raw bits", rawbit);
  PrintAndLog("worst metric (0=best..7=worst): %d at pos %d", worst, worstPos);

  // Finding the start of a UID
  int uidlen, long_wait;
  if (strcmp(Cmd, "224") == 0) {
    uidlen = 224;
    long_wait = 30;
  } else {
    uidlen = 64;
    long_wait = 29;
  }
  int start;
  int first = 0;
  for (start = 0; start <= rawbit - uidlen; start++) {
    first = rawbits[start];
    for (i = start; i < start + long_wait; i++) {
      if (rawbits[i] != first) {
        break;
      }
    }
    if (i == (start + long_wait)) {
      break;
    }
  }
  if (start == rawbit - uidlen + 1) {
    PrintAndLog("nothing to wait for");
    return 0;
  }

  // Inverting signal if needed
  if (first == 1) {
    for (i = start; i < rawbit; i++) {
      rawbits[i] = !rawbits[i];
    }
  }

  // Dumping UID
  uint8_t bits[224];
  char showbits[225];
  showbits[uidlen]='\0';
  int bit;
  i = start;
  int times = 0;
  if (uidlen > rawbit) {
    PrintAndLog("Warning: not enough raw bits to get a full UID");
    for (bit = 0; bit < rawbit; bit++) {
      bits[bit] = rawbits[i++];
      // As we cannot know the parity, let's use "." and "/"
      showbits[bit] = '.' + bits[bit];
    }
    showbits[bit+1]='\0';
    PrintAndLog("Partial UID=%s", showbits);
    return 0;
  } else {
    for (bit = 0; bit < uidlen; bit++) {
      bits[bit] = rawbits[i++];
      showbits[bit] = '0' + bits[bit];
    }
    times = 1;
  }
  PrintAndLog("UID=%s", showbits);

  // Checking UID against next occurences
  for (; i + uidlen <= rawbit;) {
    int failed = 0;
    for (bit = 0; bit < uidlen; bit++) {
      if (bits[bit] != rawbits[i++]) {
        failed = 1;
        break;
      }
    }
    if (failed == 1) {
      break;
    }
    times += 1;
  }
  PrintAndLog("Occurences: %d (expected %d)", times, (rawbit - start) / uidlen);

  // Remodulating for tag cloning
  GraphTraceLen = 32*uidlen;
  i = 0;
  int phase = 0;
  for (bit = 0; bit < uidlen; bit++) {
    if (bits[bit] == 0) {
      phase = 0;
    } else {
      phase = 1;
    }
    int j;
    for (j = 0; j < 32; j++) {
      GraphBuffer[i++] = phase;
      phase = !phase;
    }
  }

  RepaintGraphWindow();
  return 0;
}

int CmdLFRead(const char *Cmd)
{
  UsbCommand c = {CMD_ACQUIRE_RAW_ADC_SAMPLES_125K};
  // 'h' means higher-low-frequency, 134 kHz
  if(*Cmd == 'h') {
    c.arg[0] = 1;
  } else if (*Cmd == '\0') {
    c.arg[0] = 0;
  } else {
    PrintAndLog("use 'read' or 'read h'");
    return 0;
  }
  SendCommand(&c);
  WaitForResponse(CMD_ACK);
  return 0;
}

static void ChkBitstream(const char *str)
{
  int i;

  /* convert to bitstream if necessary */
  for (i = 0; i < (int)(GraphTraceLen / 2); i++)
  {
    if (GraphBuffer[i] > 1 || GraphBuffer[i] < 0)
    {
      CmdBitstream(str);
      break;
    }
  }
}

int CmdLFSim(const char *Cmd)
{
  int i;
  static int gap;

  sscanf(Cmd, "%i", &gap);

  /* convert to bitstream if necessary */
  ChkBitstream(Cmd);

  PrintAndLog("Sending data, please wait...");
  for (i = 0; i < GraphTraceLen; i += 48) {
    UsbCommand c={CMD_DOWNLOADED_SIM_SAMPLES_125K, {i, 0, 0}};
    int j;
    for (j = 0; j < 48; j++) {
      c.d.asBytes[j] = GraphBuffer[i+j];
    }
    SendCommand(&c);
    WaitForResponse(CMD_ACK);
  }

  PrintAndLog("Starting simulator...");
  UsbCommand c = {CMD_SIMULATE_TAG_125K, {GraphTraceLen, gap, 0}};
  SendCommand(&c);
  return 0;
}

int CmdLFSimBidir(const char *Cmd)
{
  /* Set ADC to twice the carrier for a slight supersampling */
  UsbCommand c = {CMD_LF_SIMULATE_BIDIR, {47, 384, 0}};
  SendCommand(&c);
  return 0;
}

/* simulate an LF Manchester encoded tag with specified bitstream, clock rate and inter-id gap */
int CmdLFSimManchester(const char *Cmd)
{
  static int clock, gap;
  static char data[1024], gapstring[8];

  /* get settings/bits */
  sscanf(Cmd, "%i %s %i", &clock, &data[0], &gap);

  /* clear our graph */
  ClearGraph(0);

  /* fill it with our bitstream */
  for (int i = 0; i < strlen(data) ; ++i)
    AppendGraph(0, clock, data[i]- '0');

  /* modulate */
  CmdManchesterMod("");

  /* show what we've done */
  RepaintGraphWindow();

  /* simulate */
  sprintf(&gapstring[0], "%i", gap);
  CmdLFSim(gapstring);
  return 0;
}

int CmdVchDemod(const char *Cmd)
{
  // Is this the entire sync pattern, or does this also include some
  // data bits that happen to be the same everywhere? That would be
  // lovely to know.
  static const int SyncPattern[] = {
    1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
    1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
    1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
    1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
    1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
    1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
  };

  // So first, we correlate for the sync pattern, and mark that.
  int bestCorrel = 0, bestPos = 0;
  int i;
  // It does us no good to find the sync pattern, with fewer than
  // 2048 samples after it...
  for (i = 0; i < (GraphTraceLen-2048); i++) {
    int sum = 0;
    int j;
    for (j = 0; j < arraylen(SyncPattern); j++) {
      sum += GraphBuffer[i+j]*SyncPattern[j];
    }
    if (sum > bestCorrel) {
      bestCorrel = sum;
      bestPos = i;
    }
  }
  PrintAndLog("best sync at %d [metric %d]", bestPos, bestCorrel);

  char bits[257];
  bits[256] = '\0';

  int worst = INT_MAX;
  int worstPos = 0;

  for (i = 0; i < 2048; i += 8) {
    int sum = 0;
    int j;
    for (j = 0; j < 8; j++) {
      sum += GraphBuffer[bestPos+i+j];
    }
    if (sum < 0) {
      bits[i/8] = '.';
    } else {
      bits[i/8] = '1';
    }
    if(abs(sum) < worst) {
      worst = abs(sum);
      worstPos = i;
    }
  }
  PrintAndLog("bits:");
  PrintAndLog("%s", bits);
  PrintAndLog("worst metric: %d at pos %d", worst, worstPos);

  if (strcmp(Cmd, "clone")==0) {
    GraphTraceLen = 0;
    char *s;
    for(s = bits; *s; s++) {
      int j;
      for(j = 0; j < 16; j++) {
        GraphBuffer[GraphTraceLen++] = (*s == '1') ? 1 : 0;
      }
    }
    RepaintGraphWindow();
  }
  return 0;
}

static command_t CommandTable[] = 
{
  {"help",        CmdHelp,            1, "This help"},
  {"cmdread",     CmdLFCommandRead,   0, "<off period> <'0' period> <'1' period> <command> ['h'] -- Modulate LF reader field to send command before read (all periods in microseconds) (option 'h' for 134)"},
  {"em4x",        CmdLFEM4X,          1, "{ EM4X RFIDs... }"},
  {"flexdemod",   CmdFlexdemod,       1, "Demodulate samples for FlexPass"},
  {"hid",         CmdLFHID,           1, "{ HID RFIDs... }"},
  {"indalademod", CmdIndalaDemod,     1, "['224'] -- Demodulate samples for Indala 64 bit UID (option '224' for 224 bit)"},
  {"read",        CmdLFRead,          0, "['h'] -- Read 125/134 kHz LF ID-only tag (option 'h' for 134)"},
  {"sim",         CmdLFSim,           0, "[GAP] -- Simulate LF tag from buffer with optional GAP (in microseconds)"},
  {"simbidir",    CmdLFSimBidir,      0, "Simulate LF tag (with bidirectional data transmission between reader and tag)"},
  {"simman",      CmdLFSimManchester, 0, "<Clock> <Bitstream> [GAP] Simulate arbitrary Manchester LF tag"},
  {"ti",          CmdLFTI,            1, "{ TI RFIDs... }"},
  {"vchdemod",    CmdVchDemod,        1, "['clone'] -- Demodulate samples for VeriChip"},
  {NULL, NULL, 0, NULL}
};

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

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