//-----------------------------------------------------------------------------
// 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;
}