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proxmark3/armsrc/iclass.c
dekoninggans@gmail.com cee5a30d53 Added iClass eavesdrop support for Proxmark3
2011-05-18 12:33:32 +00:00

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//-----------------------------------------------------------------------------
// Gerhard de Koning Gans - May 2008
// Hagen Fritsch - June 2010
// Gerhard de Koning Gans - May 2011
//
// 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.
//-----------------------------------------------------------------------------
// Routines to support iClass.
//-----------------------------------------------------------------------------
// Based on ISO14443a implementation. Still in experimental phase.
// Contribution made during a security research at Radboud University Nijmegen
//
// Please feel free to contribute and extend iClass support!!
//-----------------------------------------------------------------------------
//
// TODO:
// =====
// - iClass emulation
// - reader emulation
//
// FIX:
// ====
// We still have sometimes a demodulation error when snooping iClass communication.
// The resulting trace of a read-block-03 command may look something like this:
//
// + 22279: : 0c 03 e8 01
//
// ...with an incorrect answer...
//
// + 85: 0: TAG ff! ff! ff! ff! ff! ff! ff! ff! bb 33 bb 00 01! 0e! 04! bb !crc
//
// We still left the error signalling bytes in the traces like 0xbb
//
// A correct trace should look like this:
//
// + 21112: : 0c 03 e8 01
// + 85: 0: TAG ff ff ff ff ff ff ff ff ea f5
//
//-----------------------------------------------------------------------------
#include "proxmark3.h"
#include "apps.h"
#include "util.h"
#include "string.h"
#include "iclass.h"
static uint8_t *trace = (uint8_t *) BigBuf;
static int traceLen = 0;
static int rsamples = 0;
// CARD TO READER
// Sequence D: 11110000 modulation with subcarrier during first half
// Sequence E: 00001111 modulation with subcarrier during second half
// Sequence F: 00000000 no modulation with subcarrier
// READER TO CARD
// Sequence X: 00001100 drop after half a period
// Sequence Y: 00000000 no drop
// Sequence Z: 11000000 drop at start
#define SEC_D 0xf0
#define SEC_E 0x0f
#define SEC_F 0x00
#define SEC_X 0x0c
#define SEC_Y 0x00
#define SEC_Z 0xc0
static const uint8_t OddByteParity[256] = {
1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1
};
//static const uint8_t MajorityNibble[16] = { 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 1, 1, 1, 1, 1 };
//static const uint8_t MajorityNibble[16] = { 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 };
// BIG CHANGE - UNDERSTAND THIS BEFORE WE COMMIT
#define RECV_CMD_OFFSET 3032
#define RECV_RES_OFFSET 3096
#define DMA_BUFFER_OFFSET 3160
#define DMA_BUFFER_SIZE 4096
#define TRACE_LENGTH 3000
//-----------------------------------------------------------------------------
// The software UART that receives commands from the reader, and its state
// variables.
//-----------------------------------------------------------------------------
static struct {
enum {
STATE_UNSYNCD,
STATE_START_OF_COMMUNICATION,
STATE_RECEIVING
} state;
uint16_t shiftReg;
int bitCnt;
int byteCnt;
int byteCntMax;
int posCnt;
int nOutOfCnt;
int OutOfCnt;
int syncBit;
int parityBits;
int samples;
int highCnt;
int swapper;
int counter;
int bitBuffer;
int dropPosition;
uint8_t *output;
} Uart;
static RAMFUNC int MillerDecoding(int bit)
{
int error = 0;
int bitright;
if(!Uart.bitBuffer) {
Uart.bitBuffer = bit ^ 0xFF0;
return FALSE;
}
else {
Uart.bitBuffer <<= 4;
Uart.bitBuffer ^= bit;
}
/*if(Uart.swapper) {
Uart.output[Uart.byteCnt] = Uart.bitBuffer & 0xFF;
Uart.byteCnt++;
Uart.swapper = 0;
if(Uart.byteCnt > 15) { return TRUE; }
}
else {
Uart.swapper = 1;
}*/
if(Uart.state != STATE_UNSYNCD) {
Uart.posCnt++;
if((Uart.bitBuffer & Uart.syncBit) ^ Uart.syncBit) {
bit = 0x00;
}
else {
bit = 0x01;
}
if(((Uart.bitBuffer << 1) & Uart.syncBit) ^ Uart.syncBit) {
bitright = 0x00;
}
else {
bitright = 0x01;
}
if(bit != bitright) { bit = bitright; }
// So, now we only have to deal with *bit*, lets see...
if(Uart.posCnt == 1) {
// measurement first half bitperiod
if(!bit) {
// Drop in first half means that we are either seeing
// an SOF or an EOF.
if(Uart.nOutOfCnt == 1) {
// End of Communication
Uart.state = STATE_UNSYNCD;
Uart.highCnt = 0;
if(Uart.byteCnt == 0) {
// Its not straightforward to show single EOFs
// So just leave it and do not return TRUE
Uart.output[Uart.byteCnt] = 0xf0;
Uart.byteCnt++;
// Calculate the parity bit for the client...
Uart.parityBits = 1;
}
else {
return TRUE;
}
}
else if(Uart.state != STATE_START_OF_COMMUNICATION) {
// When not part of SOF or EOF, it is an error
Uart.state = STATE_UNSYNCD;
Uart.highCnt = 0;
error = 4;
}
}
}
else {
// measurement second half bitperiod
// Count the bitslot we are in... (ISO 15693)
Uart.nOutOfCnt++;
if(!bit) {
if(Uart.dropPosition) {
if(Uart.state == STATE_START_OF_COMMUNICATION) {
error = 1;
}
else {
error = 7;
}
// It is an error if we already have seen a drop in current frame
Uart.state = STATE_UNSYNCD;
Uart.highCnt = 0;
}
else {
Uart.dropPosition = Uart.nOutOfCnt;
}
}
Uart.posCnt = 0;
if(Uart.nOutOfCnt == Uart.OutOfCnt && Uart.OutOfCnt == 4) {
Uart.nOutOfCnt = 0;
if(Uart.state == STATE_START_OF_COMMUNICATION) {
if(Uart.dropPosition == 4) {
Uart.state = STATE_RECEIVING;
Uart.OutOfCnt = 256;
}
else if(Uart.dropPosition == 3) {
Uart.state = STATE_RECEIVING;
Uart.OutOfCnt = 4;
//Uart.output[Uart.byteCnt] = 0xdd;
//Uart.byteCnt++;
}
else {
Uart.state = STATE_UNSYNCD;
Uart.highCnt = 0;
}
Uart.dropPosition = 0;
}
else {
// RECEIVING DATA
// 1 out of 4
if(!Uart.dropPosition) {
Uart.state = STATE_UNSYNCD;
Uart.highCnt = 0;
error = 9;
}
else {
Uart.shiftReg >>= 2;
// Swap bit order
Uart.dropPosition--;
//if(Uart.dropPosition == 1) { Uart.dropPosition = 2; }
//else if(Uart.dropPosition == 2) { Uart.dropPosition = 1; }
Uart.shiftReg ^= ((Uart.dropPosition & 0x03) << 6);
Uart.bitCnt += 2;
Uart.dropPosition = 0;
if(Uart.bitCnt == 8) {
Uart.output[Uart.byteCnt] = (Uart.shiftReg & 0xff);
Uart.byteCnt++;
// Calculate the parity bit for the client...
Uart.parityBits <<= 1;
Uart.parityBits ^= OddByteParity[(Uart.shiftReg & 0xff)];
Uart.bitCnt = 0;
Uart.shiftReg = 0;
}
}
}
}
else if(Uart.nOutOfCnt == Uart.OutOfCnt) {
// RECEIVING DATA
// 1 out of 256
if(!Uart.dropPosition) {
Uart.state = STATE_UNSYNCD;
Uart.highCnt = 0;
error = 3;
}
else {
Uart.dropPosition--;
Uart.output[Uart.byteCnt] = (Uart.dropPosition & 0xff);
Uart.byteCnt++;
// Calculate the parity bit for the client...
Uart.parityBits <<= 1;
Uart.parityBits ^= OddByteParity[(Uart.dropPosition & 0xff)];
Uart.bitCnt = 0;
Uart.shiftReg = 0;
Uart.nOutOfCnt = 0;
Uart.dropPosition = 0;
}
}
/*if(error) {
Uart.output[Uart.byteCnt] = 0xAA;
Uart.byteCnt++;
Uart.output[Uart.byteCnt] = error & 0xFF;
Uart.byteCnt++;
Uart.output[Uart.byteCnt] = 0xAA;
Uart.byteCnt++;
Uart.output[Uart.byteCnt] = (Uart.bitBuffer >> 8) & 0xFF;
Uart.byteCnt++;
Uart.output[Uart.byteCnt] = Uart.bitBuffer & 0xFF;
Uart.byteCnt++;
Uart.output[Uart.byteCnt] = (Uart.syncBit >> 3) & 0xFF;
Uart.byteCnt++;
Uart.output[Uart.byteCnt] = 0xAA;
Uart.byteCnt++;
return TRUE;
}*/
}
}
else {
bit = Uart.bitBuffer & 0xf0;
bit >>= 4;
bit ^= 0x0F; // drops become 1s ;-)
if(bit) {
// should have been high or at least (4 * 128) / fc
// according to ISO this should be at least (9 * 128 + 20) / fc
if(Uart.highCnt == 8) {
// we went low, so this could be start of communication
// it turns out to be safer to choose a less significant
// syncbit... so we check whether the neighbour also represents the drop
Uart.posCnt = 1; // apparently we are busy with our first half bit period
Uart.syncBit = bit & 8;
Uart.samples = 3;
if(!Uart.syncBit) { Uart.syncBit = bit & 4; Uart.samples = 2; }
else if(bit & 4) { Uart.syncBit = bit & 4; Uart.samples = 2; bit <<= 2; }
if(!Uart.syncBit) { Uart.syncBit = bit & 2; Uart.samples = 1; }
else if(bit & 2) { Uart.syncBit = bit & 2; Uart.samples = 1; bit <<= 1; }
if(!Uart.syncBit) { Uart.syncBit = bit & 1; Uart.samples = 0;
if(Uart.syncBit && (Uart.bitBuffer & 8)) {
Uart.syncBit = 8;
// the first half bit period is expected in next sample
Uart.posCnt = 0;
Uart.samples = 3;
}
}
else if(bit & 1) { Uart.syncBit = bit & 1; Uart.samples = 0; }
Uart.syncBit <<= 4;
Uart.state = STATE_START_OF_COMMUNICATION;
Uart.bitCnt = 0;
Uart.byteCnt = 0;
Uart.parityBits = 0;
Uart.nOutOfCnt = 0;
Uart.OutOfCnt = 4; // Start at 1/4, could switch to 1/256
Uart.dropPosition = 0;
Uart.shiftReg = 0;
error = 0;
}
else {
Uart.highCnt = 0;
}
}
else {
if(Uart.highCnt < 8) {
Uart.highCnt++;
}
}
}
return FALSE;
}
//=============================================================================
// ISO 14443 Type A - Manchester
//=============================================================================
static struct {
enum {
DEMOD_UNSYNCD,
DEMOD_START_OF_COMMUNICATION,
DEMOD_START_OF_COMMUNICATION2,
DEMOD_START_OF_COMMUNICATION3,
DEMOD_SOF_COMPLETE,
DEMOD_MANCHESTER_D,
DEMOD_MANCHESTER_E,
DEMOD_END_OF_COMMUNICATION,
DEMOD_END_OF_COMMUNICATION2,
DEMOD_MANCHESTER_F,
DEMOD_ERROR_WAIT
} state;
int bitCount;
int posCount;
int syncBit;
int parityBits;
uint16_t shiftReg;
int buffer;
int buffer2;
int buffer3;
int buff;
int samples;
int len;
enum {
SUB_NONE,
SUB_FIRST_HALF,
SUB_SECOND_HALF,
SUB_BOTH
} sub;
uint8_t *output;
} Demod;
static RAMFUNC int ManchesterDecoding(int v)
{
int bit;
int modulation;
int error = 0;
bit = Demod.buffer;
Demod.buffer = Demod.buffer2;
Demod.buffer2 = Demod.buffer3;
Demod.buffer3 = v;
if(Demod.buff < 3) {
Demod.buff++;
return FALSE;
}
if(Demod.state==DEMOD_UNSYNCD) {
Demod.output[Demod.len] = 0xfa;
Demod.syncBit = 0;
//Demod.samples = 0;
Demod.posCount = 1; // This is the first half bit period, so after syncing handle the second part
/* if(bit & 0x08) { Demod.syncBit = 0x08; }
if(!Demod.syncBit) {
if(bit & 0x04) { Demod.syncBit = 0x04; }
}
else if(bit & 0x04) { Demod.syncBit = 0x04; bit <<= 4; }
if(!Demod.syncBit) {
if(bit & 0x02) { Demod.syncBit = 0x02; }
}
else if(bit & 0x02) { Demod.syncBit = 0x02; bit <<= 4; }
if(!Demod.syncBit) {
if(bit & 0x01) { Demod.syncBit = 0x01; }
if(Demod.syncBit && (Demod.buffer & 0x08)) {
Demod.syncBit = 0x08;
// The first half bitperiod is expected in next sample
Demod.posCount = 0;
Demod.output[Demod.len] = 0xfb;
}
}
else if(bit & 0x01) { Demod.syncBit = 0x01; }
*/
if(bit & 0x08) {
Demod.syncBit = 0x08;
}
if(bit & 0x04) {
if(Demod.syncBit) {
bit <<= 4;
}
Demod.syncBit = 0x04;
}
if(bit & 0x02) {
if(Demod.syncBit) {
bit <<= 2;
}
Demod.syncBit = 0x02;
}
if(bit & 0x01 && Demod.syncBit) {
Demod.syncBit = 0x01;
}
if(Demod.syncBit) {
Demod.len = 0;
Demod.state = DEMOD_START_OF_COMMUNICATION;
Demod.sub = SUB_FIRST_HALF;
Demod.bitCount = 0;
Demod.shiftReg = 0;
Demod.parityBits = 0;
Demod.samples = 0;
if(Demod.posCount) {
//if(trigger) LED_A_OFF(); // Not useful in this case...
switch(Demod.syncBit) {
case 0x08: Demod.samples = 3; break;
case 0x04: Demod.samples = 2; break;
case 0x02: Demod.samples = 1; break;
case 0x01: Demod.samples = 0; break;
}
// SOF must be long burst... otherwise stay unsynced!!!
if(!(Demod.buffer & Demod.syncBit) || !(Demod.buffer2 & Demod.syncBit)) {
Demod.state = DEMOD_UNSYNCD;
}
}
else {
// SOF must be long burst... otherwise stay unsynced!!!
if(!(Demod.buffer2 & Demod.syncBit) || !(Demod.buffer3 & Demod.syncBit)) {
Demod.state = DEMOD_UNSYNCD;
error = 0x88;
}
}
error = 0;
}
}
else {
modulation = bit & Demod.syncBit;
modulation |= ((bit << 1) ^ ((Demod.buffer & 0x08) >> 3)) & Demod.syncBit;
//modulation = ((bit << 1) ^ ((Demod.buffer & 0x08) >> 3)) & Demod.syncBit;
Demod.samples += 4;
if(Demod.posCount==0) {
Demod.posCount = 1;
if(modulation) {
Demod.sub = SUB_FIRST_HALF;
}
else {
Demod.sub = SUB_NONE;
}
}
else {
Demod.posCount = 0;
/*(modulation && (Demod.sub == SUB_FIRST_HALF)) {
if(Demod.state!=DEMOD_ERROR_WAIT) {
Demod.state = DEMOD_ERROR_WAIT;
Demod.output[Demod.len] = 0xaa;
error = 0x01;
}
}*/
//else if(modulation) {
if(modulation) {
if(Demod.sub == SUB_FIRST_HALF) {
Demod.sub = SUB_BOTH;
}
else {
Demod.sub = SUB_SECOND_HALF;
}
}
else if(Demod.sub == SUB_NONE) {
if(Demod.state == DEMOD_SOF_COMPLETE) {
Demod.output[Demod.len] = 0x0f;
Demod.len++;
Demod.parityBits <<= 1;
Demod.parityBits ^= OddByteParity[0x0f];
Demod.state = DEMOD_UNSYNCD;
// error = 0x0f;
return TRUE;
}
else {
Demod.state = DEMOD_ERROR_WAIT;
error = 0x33;
}
/*if(Demod.state!=DEMOD_ERROR_WAIT) {
Demod.state = DEMOD_ERROR_WAIT;
Demod.output[Demod.len] = 0xaa;
error = 0x01;
}*/
}
switch(Demod.state) {
case DEMOD_START_OF_COMMUNICATION:
if(Demod.sub == SUB_BOTH) {
//Demod.state = DEMOD_MANCHESTER_D;
Demod.state = DEMOD_START_OF_COMMUNICATION2;
Demod.posCount = 1;
Demod.sub = SUB_NONE;
}
else {
Demod.output[Demod.len] = 0xab;
Demod.state = DEMOD_ERROR_WAIT;
error = 0xd2;
}
break;
case DEMOD_START_OF_COMMUNICATION2:
if(Demod.sub == SUB_SECOND_HALF) {
Demod.state = DEMOD_START_OF_COMMUNICATION3;
}
else {
Demod.output[Demod.len] = 0xab;
Demod.state = DEMOD_ERROR_WAIT;
error = 0xd3;
}
break;
case DEMOD_START_OF_COMMUNICATION3:
if(Demod.sub == SUB_SECOND_HALF) {
// Demod.state = DEMOD_MANCHESTER_D;
Demod.state = DEMOD_SOF_COMPLETE;
//Demod.output[Demod.len] = Demod.syncBit & 0xFF;
//Demod.len++;
}
else {
Demod.output[Demod.len] = 0xab;
Demod.state = DEMOD_ERROR_WAIT;
error = 0xd4;
}
break;
case DEMOD_SOF_COMPLETE:
case DEMOD_MANCHESTER_D:
case DEMOD_MANCHESTER_E:
// OPPOSITE FROM ISO14443 - 11110000 = 0 (1 in 14443)
// 00001111 = 1 (0 in 14443)
if(Demod.sub == SUB_SECOND_HALF) { // SUB_FIRST_HALF
Demod.bitCount++;
Demod.shiftReg = (Demod.shiftReg >> 1) ^ 0x100;
Demod.state = DEMOD_MANCHESTER_D;
}
else if(Demod.sub == SUB_FIRST_HALF) { // SUB_SECOND_HALF
Demod.bitCount++;
Demod.shiftReg >>= 1;
Demod.state = DEMOD_MANCHESTER_E;
}
else if(Demod.sub == SUB_BOTH) {
Demod.state = DEMOD_MANCHESTER_F;
}
else {
Demod.state = DEMOD_ERROR_WAIT;
error = 0x55;
}
break;
case DEMOD_MANCHESTER_F:
// Tag response does not need to be a complete byte!
if(Demod.len > 0 || Demod.bitCount > 0) {
if(Demod.bitCount > 1) { // was > 0, do not interpret last closing bit, is part of EOF
Demod.shiftReg >>= (9 - Demod.bitCount);
Demod.output[Demod.len] = Demod.shiftReg & 0xff;
Demod.len++;
// No parity bit, so just shift a 0
Demod.parityBits <<= 1;
}
Demod.state = DEMOD_UNSYNCD;
return TRUE;
}
else {
Demod.output[Demod.len] = 0xad;
Demod.state = DEMOD_ERROR_WAIT;
error = 0x03;
}
break;
case DEMOD_ERROR_WAIT:
Demod.state = DEMOD_UNSYNCD;
break;
default:
Demod.output[Demod.len] = 0xdd;
Demod.state = DEMOD_UNSYNCD;
break;
}
/*if(Demod.bitCount>=9) {
Demod.output[Demod.len] = Demod.shiftReg & 0xff;
Demod.len++;
Demod.parityBits <<= 1;
Demod.parityBits ^= ((Demod.shiftReg >> 8) & 0x01);
Demod.bitCount = 0;
Demod.shiftReg = 0;
}*/
if(Demod.bitCount>=8) {
Demod.shiftReg >>= 1;
Demod.output[Demod.len] = (Demod.shiftReg & 0xff);
Demod.len++;
// FOR ISO15639 PARITY NOT SEND OTA, JUST CALCULATE IT FOR THE CLIENT
Demod.parityBits <<= 1;
Demod.parityBits ^= OddByteParity[(Demod.shiftReg & 0xff)];
Demod.bitCount = 0;
Demod.shiftReg = 0;
}
if(error) {
Demod.output[Demod.len] = 0xBB;
Demod.len++;
Demod.output[Demod.len] = error & 0xFF;
Demod.len++;
Demod.output[Demod.len] = 0xBB;
Demod.len++;
Demod.output[Demod.len] = bit & 0xFF;
Demod.len++;
Demod.output[Demod.len] = Demod.buffer & 0xFF;
Demod.len++;
// Look harder ;-)
Demod.output[Demod.len] = Demod.buffer2 & 0xFF;
Demod.len++;
Demod.output[Demod.len] = Demod.syncBit & 0xFF;
Demod.len++;
Demod.output[Demod.len] = 0xBB;
Demod.len++;
return TRUE;
}
}
} // end (state != UNSYNCED)
return FALSE;
}
//=============================================================================
// Finally, a `sniffer' for ISO 14443 Type A
// Both sides of communication!
//=============================================================================
//-----------------------------------------------------------------------------
// Record the sequence of commands sent by the reader to the tag, with
// triggering so that we start recording at the point that the tag is moved
// near the reader.
//-----------------------------------------------------------------------------
void RAMFUNC SnoopIClass(void)
{
// #define RECV_CMD_OFFSET 2032 // original (working as of 21/2/09) values
// #define RECV_RES_OFFSET 2096 // original (working as of 21/2/09) values
// #define DMA_BUFFER_OFFSET 2160 // original (working as of 21/2/09) values
// #define DMA_BUFFER_SIZE 4096 // original (working as of 21/2/09) values
// #define TRACE_LENGTH 2000 // original (working as of 21/2/09) values
// We won't start recording the frames that we acquire until we trigger;
// a good trigger condition to get started is probably when we see a
// response from the tag.
int triggered = FALSE; // FALSE to wait first for card
// The command (reader -> tag) that we're receiving.
// The length of a received command will in most cases be no more than 18 bytes.
// So 32 should be enough!
uint8_t *receivedCmd = (((uint8_t *)BigBuf) + RECV_CMD_OFFSET);
// The response (tag -> reader) that we're receiving.
uint8_t *receivedResponse = (((uint8_t *)BigBuf) + RECV_RES_OFFSET);
// As we receive stuff, we copy it from receivedCmd or receivedResponse
// into trace, along with its length and other annotations.
//uint8_t *trace = (uint8_t *)BigBuf;
traceLen = 0; // uncommented to fix ISSUE 15 - gerhard - jan2011
// The DMA buffer, used to stream samples from the FPGA
int8_t *dmaBuf = ((int8_t *)BigBuf) + DMA_BUFFER_OFFSET;
int lastRxCounter;
int8_t *upTo;
int smpl;
int maxBehindBy = 0;
// Count of samples received so far, so that we can include timing
// information in the trace buffer.
int samples = 0;
rsamples = 0;
memset(trace, 0x44, RECV_CMD_OFFSET);
// Set up the demodulator for tag -> reader responses.
Demod.output = receivedResponse;
Demod.len = 0;
Demod.state = DEMOD_UNSYNCD;
// Setup for the DMA.
FpgaSetupSsc();
upTo = dmaBuf;
lastRxCounter = DMA_BUFFER_SIZE;
FpgaSetupSscDma((uint8_t *)dmaBuf, DMA_BUFFER_SIZE);
// And the reader -> tag commands
memset(&Uart, 0, sizeof(Uart));
Uart.output = receivedCmd;
Uart.byteCntMax = 32; // was 100 (greg)////////////////////////////////////////////////////////////////////////
Uart.state = STATE_UNSYNCD;
// And put the FPGA in the appropriate mode
// Signal field is off with the appropriate LED
LED_D_OFF();
FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_SNIFFER);
SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
int div = 0;
//int div2 = 0;
int decbyte = 0;
int decbyter = 0;
// And now we loop, receiving samples.
for(;;) {
LED_A_ON();
WDT_HIT();
int behindBy = (lastRxCounter - AT91C_BASE_PDC_SSC->PDC_RCR) &
(DMA_BUFFER_SIZE-1);
if(behindBy > maxBehindBy) {
maxBehindBy = behindBy;
if(behindBy > 400) {
Dbprintf("blew circular buffer! behindBy=0x%x", behindBy);
goto done;
}
}
if(behindBy < 1) continue;
LED_A_OFF();
smpl = upTo[0];
upTo++;
lastRxCounter -= 1;
if(upTo - dmaBuf > DMA_BUFFER_SIZE) {
upTo -= DMA_BUFFER_SIZE;
lastRxCounter += DMA_BUFFER_SIZE;
AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) upTo;
AT91C_BASE_PDC_SSC->PDC_RNCR = DMA_BUFFER_SIZE;
}
//samples += 4;
samples += 1;
//div2++;
//if(div2 > 3) {
//div2 = 0;
//decbyte ^= ((smpl & 0x01) << (3 - div));
//decbyte ^= (((smpl & 0x01) | ((smpl & 0x02) >> 1)) << (3 - div)); // better already...
//decbyte ^= (((smpl & 0x01) | ((smpl & 0x02) >> 1) | ((smpl & 0x04) >> 2)) << (3 - div)); // even better...
if(smpl & 0xF) {
decbyte ^= (1 << (3 - div));
}
//decbyte ^= (MajorityNibble[(smpl & 0x0F)] << (3 - div));
// FOR READER SIDE COMMUMICATION...
//decbyte ^= ((smpl & 0x10) << (3 - div));
decbyter <<= 2;
decbyter ^= (smpl & 0x30);
div++;
if((div + 1) % 2 == 0) {
smpl = decbyter;
if(MillerDecoding((smpl & 0xF0) >> 4)) {
rsamples = samples - Uart.samples;
LED_C_ON();
//if(triggered) {
trace[traceLen++] = ((rsamples >> 0) & 0xff);
trace[traceLen++] = ((rsamples >> 8) & 0xff);
trace[traceLen++] = ((rsamples >> 16) & 0xff);
trace[traceLen++] = ((rsamples >> 24) & 0xff);
trace[traceLen++] = ((Uart.parityBits >> 0) & 0xff);
trace[traceLen++] = ((Uart.parityBits >> 8) & 0xff);
trace[traceLen++] = ((Uart.parityBits >> 16) & 0xff);
trace[traceLen++] = ((Uart.parityBits >> 24) & 0xff);
trace[traceLen++] = Uart.byteCnt;
memcpy(trace+traceLen, receivedCmd, Uart.byteCnt);
traceLen += Uart.byteCnt;
if(traceLen > TRACE_LENGTH) break;
//}
/* And ready to receive another command. */
Uart.state = STATE_UNSYNCD;
/* And also reset the demod code, which might have been */
/* false-triggered by the commands from the reader. */
Demod.state = DEMOD_UNSYNCD;
LED_B_OFF();
Uart.byteCnt = 0;
}
decbyter = 0;
}
if(div > 3) {
smpl = decbyte;
if(ManchesterDecoding(smpl & 0x0F)) {
rsamples = samples - Demod.samples;
LED_B_ON();
// timestamp, as a count of samples
trace[traceLen++] = ((rsamples >> 0) & 0xff);
trace[traceLen++] = ((rsamples >> 8) & 0xff);
trace[traceLen++] = ((rsamples >> 16) & 0xff);
trace[traceLen++] = 0x80 | ((rsamples >> 24) & 0xff);
trace[traceLen++] = ((Demod.parityBits >> 0) & 0xff);
trace[traceLen++] = ((Demod.parityBits >> 8) & 0xff);
trace[traceLen++] = ((Demod.parityBits >> 16) & 0xff);
trace[traceLen++] = ((Demod.parityBits >> 24) & 0xff);
// length
trace[traceLen++] = Demod.len;
memcpy(trace+traceLen, receivedResponse, Demod.len);
traceLen += Demod.len;
if(traceLen > TRACE_LENGTH) break;
triggered = TRUE;
// And ready to receive another response.
memset(&Demod, 0, sizeof(Demod));
Demod.output = receivedResponse;
Demod.state = DEMOD_UNSYNCD;
LED_C_OFF();
}
div = 0;
decbyte = 0x00;
}
//}
if(BUTTON_PRESS()) {
DbpString("cancelled_a");
goto done;
}
}
DbpString("COMMAND FINISHED");
Dbprintf("%x %x %x", maxBehindBy, Uart.state, Uart.byteCnt);
Dbprintf("%x %x %x", Uart.byteCntMax, traceLen, (int)Uart.output[0]);
done:
AT91C_BASE_PDC_SSC->PDC_PTCR = AT91C_PDC_RXTDIS;
Dbprintf("%x %x %x", maxBehindBy, Uart.state, Uart.byteCnt);
Dbprintf("%x %x %x", Uart.byteCntMax, traceLen, (int)Uart.output[0]);
LED_A_OFF();
LED_B_OFF();
LED_C_OFF();
LED_D_OFF();
}
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