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proxmark3/armsrc/iso14443b.c

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//-----------------------------------------------------------------------------
// Jonathan Westhues, split Nov 2006
//
// 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 ISO 14443B. This includes both the reader software and
// the `fake tag' modes.
//-----------------------------------------------------------------------------
#include "iso14443b.h"
#define RECEIVE_SAMPLES_TIMEOUT 50000
#define ISO14443B_DMA_BUFFER_SIZE 256
// Guard Time (per 14443-2)
#define TR0 0
// Synchronization time (per 14443-2)
#define TR1 0
// Frame Delay Time PICC to PCD (per 14443-3 Amendment 1)
#define TR2 0
// 4sample
//#define SEND4STUFFBIT(x) ToSendStuffBit(x);ToSendStuffBit(x);ToSendStuffBit(x);ToSendStuffBit(x);
#define SEND4STUFFBIT(x) ToSendStuffBit(x);
static void switch_off(void);
// the block number for the ISO14443-4 PCB (used with APDUs)
static uint8_t pcb_blocknum = 0;
static uint32_t iso14b_timeout = RECEIVE_SAMPLES_TIMEOUT;
// param timeout is in ftw_
void iso14b_set_timeout(uint32_t timeout) {
// 9.4395us = 1etu.
// clock is about 1.5 us
iso14b_timeout = timeout;
if(MF_DBGLEVEL >= 2) Dbprintf("ISO14443B Timeout set to %ld fwt", iso14b_timeout);
}
static void switch_off(void){
if (MF_DBGLEVEL > 3) Dbprintf("switch_off");
FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
SpinDelay(100);
FpgaDisableSscDma();
set_tracing(FALSE);
LEDsoff();
}
//=============================================================================
// An ISO 14443 Type B tag. We listen for commands from the reader, using
// a UART kind of thing that's implemented in software. When we get a
// frame (i.e., a group of bytes between SOF and EOF), we check the CRC.
// If it's good, then we can do something appropriate with it, and send
// a response.
//=============================================================================
//-----------------------------------------------------------------------------
// The software UART that receives commands from the reader, and its state variables.
//-----------------------------------------------------------------------------
static struct {
enum {
STATE_UNSYNCD,
STATE_GOT_FALLING_EDGE_OF_SOF,
STATE_AWAITING_START_BIT,
STATE_RECEIVING_DATA
} state;
uint16_t shiftReg;
int bitCnt;
int byteCnt;
int byteCntMax;
int posCnt;
uint8_t *output;
} Uart;
static void UartReset() {
Uart.state = STATE_UNSYNCD;
Uart.shiftReg = 0;
Uart.bitCnt = 0;
Uart.byteCnt = 0;
Uart.byteCntMax = MAX_FRAME_SIZE;
Uart.posCnt = 0;
}
static void UartInit(uint8_t *data) {
Uart.output = data;
UartReset();
// memset(Uart.output, 0x00, MAX_FRAME_SIZE);
}
//-----------------------------------------------------------------------------
// The software Demod that receives commands from the tag, and its state variables.
//-----------------------------------------------------------------------------
static struct {
enum {
DEMOD_UNSYNCD,
DEMOD_PHASE_REF_TRAINING,
DEMOD_AWAITING_FALLING_EDGE_OF_SOF,
DEMOD_GOT_FALLING_EDGE_OF_SOF,
DEMOD_AWAITING_START_BIT,
DEMOD_RECEIVING_DATA
} state;
uint16_t bitCount;
int posCount;
int thisBit;
/* this had been used to add RSSI (Received Signal Strength Indication) to traces. Currently not implemented.
int metric;
int metricN;
*/
uint16_t shiftReg;
uint8_t *output;
uint16_t len;
int sumI;
int sumQ;
uint32_t startTime, endTime;
} Demod;
// Clear out the state of the "UART" that receives from the tag.
static void DemodReset() {
Demod.state = DEMOD_UNSYNCD;
Demod.bitCount = 0;
Demod.posCount = 0;
Demod.thisBit = 0;
Demod.shiftReg = 0;
Demod.len = 0;
Demod.sumI = 0;
Demod.sumQ = 0;
Demod.startTime = 0;
Demod.endTime = 0;
}
static void DemodInit(uint8_t *data) {
Demod.output = data;
DemodReset();
// memset(Demod.output, 0x00, MAX_FRAME_SIZE);
}
void AppendCrc14443b(uint8_t* data, int len) {
ComputeCrc14443(CRC_14443_B, data, len, data+len, data+len+1);
}
//-----------------------------------------------------------------------------
// Code up a string of octets at layer 2 (including CRC, we don't generate
// that here) so that they can be transmitted to the reader. Doesn't transmit
// them yet, just leaves them ready to send in ToSend[].
//-----------------------------------------------------------------------------
static void CodeIso14443bAsTag(const uint8_t *cmd, int len) {
/* ISO 14443 B
*
* Reader to card | ASK - Amplitude Shift Keying Modulation (PCD to PICC for Type B) (NRZ-L encodig)
* Card to reader | BPSK - Binary Phase Shift Keying Modulation, (PICC to PCD for Type B)
*
* fc - carrier frequency 13.56mHz
* TR0 - Guard Time per 14443-2
* TR1 - Synchronization Time per 14443-2
* TR2 - PICC to PCD Frame Delay Time (per 14443-3 Amendment 1)
*
* Elementary Time Unit (ETU) is
* - 128 Carrier Cycles (9.4395 µS) = 8 Subcarrier Units
* - 1 ETU = 1 bit
* - 10 ETU = 1 startbit, 8 databits, 1 stopbit (10bits length)
* - startbit is a 0
* - stopbit is a 1
*
* Start of frame (SOF) is
* - [10-11] ETU of ZEROS, unmodulated time
* - [2-3] ETU of ONES,
*
* End of frame (EOF) is
* - [10-11] ETU of ZEROS, unmodulated time
*
* -TO VERIFY THIS BELOW-
* The mode FPGA_MAJOR_MODE_HF_SIMULATOR | FPGA_HF_SIMULATOR_MODULATE_BPSK which we use to simulate tag
* works like this:
* - A 1-bit input to the FPGA becomes 8 pulses at 847.5kHz (9.44µS)
* - A 0-bit input to the FPGA becomes an unmodulated time of 9.44µS
*
*
*
* Card sends data ub 847.e kHz subcarrier
* 848k = 9.44µS = 128 fc
* 424k = 18.88µS = 256 fc
* 212k = 37.76µS = 512 fc
* 106k = 75.52µS = 1024 fc
*
* Reader data transmission:
* - no modulation ONES
* - SOF
* - Command, data and CRC_B
* - EOF
* - no modulation ONES
*
* Card data transmission
* - TR1
* - SOF
* - data (each bytes is: 1startbit,8bits, 1stopbit)
* - CRC_B
* - EOF
*
* FPGA implementation :
* At this point only Type A is implemented. This means that we are using a
* bit rate of 106 kbit/s, or fc/128. Oversample by 4, which ought to make
* things practical for the ARM (fc/32, 423.8 kbits/s, ~50 kbytes/s)
*
*/
// ToSendStuffBit, 40 calls
// 1 ETU = 1startbit, 1stopbit, 8databits == 10bits.
// 1 ETU = 10 * 4 == 40 stuffbits ( ETU_TAG_BIT )
int i,j;
uint8_t b;
ToSendReset();
// Transmit a burst of ones, as the initial thing that lets the
// reader get phase sync.
// This loop is TR1, per specification
// TR1 minimum must be > 80/fs
// TR1 maximum 200/fs
// 80/fs < TR1 < 200/fs
// 10 ETU < TR1 < 24 ETU
// Send SOF.
// 10-11 ETU * 4times samples ZEROS
for(i = 0; i < 10; i++) { SEND4STUFFBIT(0); }
// 2-3 ETU * 4times samples ONES
for(i = 0; i < 3; i++) { SEND4STUFFBIT(1); }
// data
for(i = 0; i < len; ++i) {
// Start bit
SEND4STUFFBIT(0);
// Data bits
b = cmd[i];
for(j = 0; j < 8; ++j) {
if(b & 1) {
SEND4STUFFBIT(1);
} else {
SEND4STUFFBIT(0);
}
b >>= 1;
}
// Stop bit
SEND4STUFFBIT(1);
// Extra Guard bit
// For PICC it ranges 0-18us (1etu = 9us)
SEND4STUFFBIT(1);
}
// Send EOF.
// 10-11 ETU * 4 sample rate = ZEROS
for(i = 0; i < 10; i++) { SEND4STUFFBIT(0); }
// why this?
for(i = 0; i < 40; i++) { SEND4STUFFBIT(1); }
// Convert from last byte pos to length
++ToSendMax;
}
/* Receive & handle a bit coming from the reader.
*
* This function is called 4 times per bit (every 2 subcarrier cycles).
* Subcarrier frequency fs is 848kHz, 1/fs = 1,18us, i.e. function is called every 2,36us
*
* LED handling:
* LED A -> ON once we have received the SOF and are expecting the rest.
* LED A -> OFF once we have received EOF or are in error state or unsynced
*
* Returns: true if we received a EOF
* false if we are still waiting for some more
*/
static RAMFUNC int Handle14443bReaderUartBit(uint8_t bit) {
switch(Uart.state) {
case STATE_UNSYNCD:
if(!bit) {
// we went low, so this could be the beginning of an SOF
Uart.state = STATE_GOT_FALLING_EDGE_OF_SOF;
Uart.posCnt = 0;
Uart.bitCnt = 0;
}
break;
case STATE_GOT_FALLING_EDGE_OF_SOF:
Uart.posCnt++;
if(Uart.posCnt == 2) { // sample every 4 1/fs in the middle of a bit
if(bit) {
if(Uart.bitCnt > 9) {
// we've seen enough consecutive
// zeros that it's a valid SOF
Uart.posCnt = 0;
Uart.byteCnt = 0;
Uart.state = STATE_AWAITING_START_BIT;
LED_A_ON(); // Indicate we got a valid SOF
} else {
// didn't stay down long enough
// before going high, error
Uart.state = STATE_UNSYNCD;
}
} else {
// do nothing, keep waiting
}
Uart.bitCnt++;
}
if(Uart.posCnt >= 4) Uart.posCnt = 0;
if(Uart.bitCnt > 12) {
// Give up if we see too many zeros without
// a one, too.
LED_A_OFF();
Uart.state = STATE_UNSYNCD;
}
break;
case STATE_AWAITING_START_BIT:
Uart.posCnt++;
if(bit) {
if(Uart.posCnt > 50/2) { // max 57us between characters = 49 1/fs, max 3 etus after low phase of SOF = 24 1/fs
// stayed high for too long between
// characters, error
Uart.state = STATE_UNSYNCD;
}
} else {
// falling edge, this starts the data byte
Uart.posCnt = 0;
Uart.bitCnt = 0;
Uart.shiftReg = 0;
Uart.state = STATE_RECEIVING_DATA;
}
break;
case STATE_RECEIVING_DATA:
Uart.posCnt++;
if(Uart.posCnt == 2) {
// time to sample a bit
Uart.shiftReg >>= 1;
if(bit) {
Uart.shiftReg |= 0x200;
}
Uart.bitCnt++;
}
if(Uart.posCnt >= 4) {
Uart.posCnt = 0;
}
if(Uart.bitCnt == 10) {
if((Uart.shiftReg & 0x200) && !(Uart.shiftReg & 0x001))
{
// this is a data byte, with correct
// start and stop bits
Uart.output[Uart.byteCnt] = (Uart.shiftReg >> 1) & 0xff;
Uart.byteCnt++;
if(Uart.byteCnt >= Uart.byteCntMax) {
// Buffer overflowed, give up
LED_A_OFF();
Uart.state = STATE_UNSYNCD;
} else {
// so get the next byte now
Uart.posCnt = 0;
Uart.state = STATE_AWAITING_START_BIT;
}
} else if (Uart.shiftReg == 0x000) {
// this is an EOF byte
LED_A_OFF(); // Finished receiving
Uart.state = STATE_UNSYNCD;
if (Uart.byteCnt != 0) {
return TRUE;
}
} else {
// this is an error
LED_A_OFF();
Uart.state = STATE_UNSYNCD;
}
}
break;
default:
LED_A_OFF();
Uart.state = STATE_UNSYNCD;
break;
}
return FALSE;
}
//-----------------------------------------------------------------------------
// Receive a command (from the reader to us, where we are the simulated tag),
// and store it in the given buffer, up to the given maximum length. Keeps
// spinning, waiting for a well-framed command, until either we get one
// (returns TRUE) or someone presses the pushbutton on the board (FALSE).
//
// Assume that we're called with the SSC (to the FPGA) and ADC path set
// correctly.
//-----------------------------------------------------------------------------
static int GetIso14443bCommandFromReader(uint8_t *received, uint16_t *len) {
// Set FPGA mode to "simulated ISO 14443B tag", no modulation (listen
// only, since we are receiving, not transmitting).
// Signal field is off with the appropriate LED
LED_D_OFF();
FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_SIMULATOR | FPGA_HF_SIMULATOR_NO_MODULATION);
StartCountSspClk();
volatile uint8_t b;
// clear receiving shift register and holding register
// What does this loop do? Is it TR1?
for(uint8_t c = 0; c < 10;) {
if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
AT91C_BASE_SSC->SSC_THR = 0xFF;
++c;
}
}
// Now run a `software UART' on the stream of incoming samples.
UartInit(received);
b = 0;
uint8_t mask;
while( !BUTTON_PRESS() ) {
WDT_HIT();
if ( AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY ) {
b = (uint8_t) AT91C_BASE_SSC->SSC_RHR;
for ( mask = 0x80; mask != 0; mask >>= 1) {
if ( Handle14443bReaderUartBit(b & mask)) {
*len = Uart.byteCnt;
return TRUE;
}
}
}
}
return FALSE;
}
void ClearFpgaShiftingRegisters(void){
volatile uint8_t b;
// clear receiving shift register and holding register
while(!(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY));
b = AT91C_BASE_SSC->SSC_RHR; (void) b;
while(!(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY));
b = AT91C_BASE_SSC->SSC_RHR; (void) b;
// wait for the FPGA to signal fdt_indicator == 1 (the FPGA is ready to queue new data in its delay line)
for (uint8_t j = 0; j < 5; j++) { // allow timeout - better late than never
while(!(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY));
if (AT91C_BASE_SSC->SSC_RHR) break;
}
// Clear TXRDY:
AT91C_BASE_SSC->SSC_THR = 0xFF;
}
void WaitForFpgaDelayQueueIsEmpty( uint16_t delay ){
// Ensure that the FPGA Delay Queue is empty before we switch to TAGSIM_LISTEN again:
uint8_t fpga_queued_bits = delay >> 3; // twich /8 ?? >>3,
for (uint8_t i = 0; i <= fpga_queued_bits/8 + 1; ) {
if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
AT91C_BASE_SSC->SSC_THR = 0xFF;
i++;
}
}
}
static void TransmitFor14443b_AsTag( uint8_t *response, uint16_t len) {
// Signal field is off with the appropriate LED
LED_D_OFF();
uint16_t fpgasendQueueDelay = 0;
// Modulate BPSK
FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_SIMULATOR | FPGA_HF_SIMULATOR_MODULATE_BPSK);
ClearFpgaShiftingRegisters();
FpgaSetupSsc();
// Transmit the response.
for(uint16_t i = 0; i < len;) {
if(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXRDY) {
AT91C_BASE_SSC->SSC_THR = response[++i];
fpgasendQueueDelay = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
}
}
WaitForFpgaDelayQueueIsEmpty(fpgasendQueueDelay);
}
//-----------------------------------------------------------------------------
// Main loop of simulated tag: receive commands from reader, decide what
// response to send, and send it.
//-----------------------------------------------------------------------------
void SimulateIso14443bTag(uint32_t pupi) {
///////////// setup device.
FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
// allocate command receive buffer
BigBuf_free();
BigBuf_Clear_ext(false);
clear_trace(); //sim
set_tracing(TRUE);
// connect Demodulated Signal to ADC:
SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
// Set up the synchronous serial port
FpgaSetupSsc();
/////////////
uint16_t len, cmdsReceived = 0;
int cardSTATE = SIM_NOFIELD;
int vHf = 0; // in mV
// uint32_t time_0 = 0;
// uint32_t t2r_time = 0;
// uint32_t r2t_time = 0;
uint8_t *receivedCmd = BigBuf_malloc(MAX_FRAME_SIZE);
// the only commands we understand is WUPB, AFI=0, Select All, N=1:
// static const uint8_t cmdWUPB[] = { ISO14443B_REQB, 0x00, 0x08, 0x39, 0x73 }; // WUPB
// ... and REQB, AFI=0, Normal Request, N=1:
// static const uint8_t cmdREQB[] = { ISO14443B_REQB, 0x00, 0x00, 0x71, 0xFF }; // REQB
// ... and ATTRIB
// static const uint8_t cmdATTRIB[] = { ISO14443B_ATTRIB, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff}; // ATTRIB
// ... if not PUPI/UID is supplied we always respond with ATQB, PUPI = 820de174, Application Data = 0x20381922,
// supports only 106kBit/s in both directions, max frame size = 32Bytes,
// supports ISO14443-4, FWI=8 (77ms), NAD supported, CID not supported:
uint8_t respATQB[] = { 0x50, 0x82, 0x0d, 0xe1, 0x74, 0x20, 0x38, 0x19,
0x22, 0x00, 0x21, 0x85, 0x5e, 0xd7 };
// response to HLTB and ATTRIB
static const uint8_t respOK[] = {0x00, 0x78, 0xF0};
// ...PUPI/UID supplied from user. Adjust ATQB response accordingly
if ( pupi > 0 ) {
num_to_bytes(pupi, 4, respATQB+1);
ComputeCrc14443(CRC_14443_B, respATQB, 12, respATQB+13, respATQB+14);
}
// prepare "ATQB" tag answer (encoded):
CodeIso14443bAsTag(respATQB, sizeof(respATQB));
uint8_t *encodedATQB = BigBuf_malloc(ToSendMax);
uint16_t encodedATQBLen = ToSendMax;
memcpy(encodedATQB, ToSend, ToSendMax);
// prepare "OK" tag answer (encoded):
CodeIso14443bAsTag(respOK, sizeof(respOK));
uint8_t *encodedOK = BigBuf_malloc(ToSendMax);
uint16_t encodedOKLen = ToSendMax;
memcpy(encodedOK, ToSend, ToSendMax);
// Simulation loop
while (!BUTTON_PRESS() && !usb_poll_validate_length()) {
WDT_HIT();
// find reader field
if (cardSTATE == SIM_NOFIELD) {
vHf = (MAX_ADC_HF_VOLTAGE * AvgAdc(ADC_CHAN_HF)) >> 10;
if ( vHf > MF_MINFIELDV ) {
cardSTATE = SIM_IDLE;
LED_A_ON();
}
}
if (cardSTATE == SIM_NOFIELD) continue;
// Get reader command
if (!GetIso14443bCommandFromReader(receivedCmd, &len)) {
Dbprintf("button pressed, received %d commands", cmdsReceived);
break;
}
// ISO14443-B protocol states:
// REQ or WUP request in ANY state
// WUP in HALTED state
if (len == 5 ) {
if ( (receivedCmd[0] == ISO14443B_REQB && (receivedCmd[2] & 0x8)== 0x8 && cardSTATE == SIM_HALTED) ||
receivedCmd[0] == ISO14443B_REQB ){
LogTrace(receivedCmd, len, 0, 0, NULL, TRUE);
cardSTATE = SIM_SELECTING;
}
}
/*
* How should this flow go?
* REQB or WUPB
* send response ( waiting for Attrib)
* ATTRIB
* send response ( waiting for commands 7816)
* HALT
send halt response ( waiting for wupb )
*/
switch(cardSTATE){
case SIM_NOFIELD:
case SIM_HALTED:
case SIM_IDLE:{
LogTrace(receivedCmd, len, 0, 0, NULL, TRUE);
break;
}
case SIM_SELECTING: {
TransmitFor14443b_AsTag( encodedATQB, encodedATQBLen );
LogTrace(respATQB, sizeof(respATQB), 0, 0, NULL, FALSE);
cardSTATE = SIM_WORK;
break;
}
case SIM_HALTING: {
TransmitFor14443b_AsTag( encodedOK, encodedOKLen );
LogTrace(respOK, sizeof(respOK), 0, 0, NULL, FALSE);
cardSTATE = SIM_HALTED;
break;
}
case SIM_ACKNOWLEDGE:{
TransmitFor14443b_AsTag( encodedOK, encodedOKLen );
LogTrace(respOK, sizeof(respOK), 0, 0, NULL, FALSE);
cardSTATE = SIM_IDLE;
break;
}
case SIM_WORK:{
if ( len == 7 && receivedCmd[0] == ISO14443B_HALT ) {
cardSTATE = SIM_HALTED;
} else if ( len == 11 && receivedCmd[0] == ISO14443B_ATTRIB ) {
cardSTATE = SIM_ACKNOWLEDGE;
} else {
// Todo:
// - SLOT MARKER
// - ISO7816
// - emulate with a memory dump
Dbprintf("new cmd from reader: len=%d, cmdsRecvd=%d", len, cmdsReceived);
// CRC Check
uint8_t b1, b2;
if (len >= 3){ // if crc exists
ComputeCrc14443(CRC_14443_B, receivedCmd, len-2, &b1, &b2);
if(b1 != receivedCmd[len-2] || b2 != receivedCmd[len-1])
DbpString("+++CRC fail");
else
DbpString("CRC passes");
}
cardSTATE = SIM_IDLE;
}
break;
}
default: break;
}
++cmdsReceived;
if(cmdsReceived > 1000) {
DbpString("14B Simulate, 1000 commands later...");
break;
}
}
if (MF_DBGLEVEL >= 1) Dbprintf("Emulator stopped. Tracing: %d trace length: %d ", tracing, BigBuf_get_traceLen());
switch_off(); //simulate
}
//=============================================================================
// An ISO 14443 Type B reader. We take layer two commands, code them
// appropriately, and then send them to the tag. We then listen for the
// tag's response, which we leave in the buffer to be demodulated on the
// PC side.
//=============================================================================
/*
* Handles reception of a bit from the tag
*
* This function is called 2 times per bit (every 4 subcarrier cycles).
* Subcarrier frequency fs is 848kHz, 1/fs = 1,18us, i.e. function is called every 4,72us
*
* LED handling:
* LED C -> ON once we have received the SOF and are expecting the rest.
* LED C -> OFF once we have received EOF or are unsynced
*
* Returns: true if we received a EOF
* false if we are still waiting for some more
*
*/
#ifndef SUBCARRIER_DETECT_THRESHOLD
# define SUBCARRIER_DETECT_THRESHOLD 8
#endif
static RAMFUNC int Handle14443bTagSamplesDemod(int ci, int cq) {
int v=0;// , myI, myQ = 0;
// The soft decision on the bit uses an estimate of just the
// quadrant of the reference angle, not the exact angle.
#define MAKE_SOFT_DECISION() { \
if(Demod.sumI > 0) { \
v = ci; \
} else { \
v = -ci; \
} \
if(Demod.sumQ > 0) { \
v += cq; \
} else { \
v -= cq; \
} \
}
// Subcarrier amplitude v = sqrt(ci^2 + cq^2), approximated here by abs(ci) + abs(cq)
// Subcarrier amplitude v = sqrt(ci^2 + cq^2), approximated here by max(abs(ci),abs(cq)) + 1/2*min(abs(ci),abs(cq)))
#define CHECK_FOR_SUBCARRIER() { \
if(ci < 0) { \
if(cq < 0) { /* ci < 0, cq < 0 */ \
if (cq < ci) { \
v = -cq - (ci >> 1); \
} else { \
v = -ci - (cq >> 1); \
} \
} else { /* ci < 0, cq >= 0 */ \
if (cq < -ci) { \
v = -ci + (cq >> 1); \
} else { \
v = cq - (ci >> 1); \
} \
} \
} else { \
if(cq < 0) { /* ci >= 0, cq < 0 */ \
if (-cq < ci) { \
v = ci - (cq >> 1); \
} else { \
v = -cq + (ci >> 1); \
} \
} else { /* ci >= 0, cq >= 0 */ \
if (cq < ci) { \
v = ci + (cq >> 1); \
} else { \
v = cq + (ci >> 1); \
} \
} \
} \
}
//note: couldn't we just use MAX(ABS(ci),ABS(cq)) + (MIN(ABS(ci),ABS(cq))/2) from common.h - marshmellow
#define CHECK_FOR_SUBCARRIER_un() { \
myI = ABS(ci); \
myQ = ABS(cq); \
v = MAX(myI,myQ) + (MIN(myI,myQ) >> 1); \
}
switch(Demod.state) {
case DEMOD_UNSYNCD:
CHECK_FOR_SUBCARRIER();
// subcarrier detected
if(v > SUBCARRIER_DETECT_THRESHOLD) {
Demod.state = DEMOD_PHASE_REF_TRAINING;
Demod.sumI = ci;
Demod.sumQ = cq;
Demod.posCount = 1;
}
break;
case DEMOD_PHASE_REF_TRAINING:
if(Demod.posCount < 8) {
CHECK_FOR_SUBCARRIER();
if (v > SUBCARRIER_DETECT_THRESHOLD) {
// set the reference phase (will code a logic '1') by averaging over 32 1/fs.
// note: synchronization time > 80 1/fs
Demod.sumI += ci;
Demod.sumQ += cq;
++Demod.posCount;
} else {
// subcarrier lost
Demod.state = DEMOD_UNSYNCD;
}
} else {
Demod.state = DEMOD_AWAITING_FALLING_EDGE_OF_SOF;
}
break;
case DEMOD_AWAITING_FALLING_EDGE_OF_SOF:
MAKE_SOFT_DECISION();
if(v < 0) { // logic '0' detected
Demod.state = DEMOD_GOT_FALLING_EDGE_OF_SOF;
Demod.posCount = 0; // start of SOF sequence
} else {
// maximum length of TR1 = 200 1/fs
if(Demod.posCount > 25*2) Demod.state = DEMOD_UNSYNCD;
}
++Demod.posCount;
break;
case DEMOD_GOT_FALLING_EDGE_OF_SOF:
++Demod.posCount;
MAKE_SOFT_DECISION();
if(v > 0) {
// low phase of SOF too short (< 9 etu). Note: spec is >= 10, but FPGA tends to "smear" edges
if(Demod.posCount < 9*2) {
Demod.state = DEMOD_UNSYNCD;
} else {
LED_C_ON(); // Got SOF
Demod.startTime = GetCountSspClk();
Demod.state = DEMOD_AWAITING_START_BIT;
Demod.posCount = 0;
Demod.len = 0;
}
} else {
// low phase of SOF too long (> 12 etu)
if (Demod.posCount > 12*2) {
Demod.state = DEMOD_UNSYNCD;
LED_C_OFF();
}
}
break;
case DEMOD_AWAITING_START_BIT:
++Demod.posCount;
MAKE_SOFT_DECISION();
if (v > 0) {
if(Demod.posCount > 3*2) { // max 19us between characters = 16 1/fs, max 3 etu after low phase of SOF = 24 1/fs
Demod.state = DEMOD_UNSYNCD;
LED_C_OFF();
}
} else { // start bit detected
Demod.bitCount = 0;
Demod.posCount = 1; // this was the first half
Demod.thisBit = v;
Demod.shiftReg = 0;
Demod.state = DEMOD_RECEIVING_DATA;
}
break;
case DEMOD_RECEIVING_DATA:
MAKE_SOFT_DECISION();
if (Demod.posCount == 0) {
// first half of bit
Demod.thisBit = v;
Demod.posCount = 1;
} else {
// second half of bit
Demod.thisBit += v;
Demod.shiftReg >>= 1;
// logic '1'
if(Demod.thisBit > 0) Demod.shiftReg |= 0x200;
++Demod.bitCount;
if(Demod.bitCount == 10) {
uint16_t s = Demod.shiftReg;
// stop bit == '1', start bit == '0'
if((s & 0x200) && !(s & 0x001)) {
uint8_t b = (s >> 1);
Demod.output[Demod.len] = b;
++Demod.len;
Demod.state = DEMOD_AWAITING_START_BIT;
} else {
Demod.state = DEMOD_UNSYNCD;
Demod.endTime = GetCountSspClk();
LED_C_OFF();
// This is EOF (start, stop and all data bits == '0'
if(s == 0) return TRUE;
}
}
Demod.posCount = 0;
}
break;
default:
Demod.state = DEMOD_UNSYNCD;
LED_C_OFF();
break;
}
return FALSE;
}
/*
* Demodulate the samples we received from the tag, also log to tracebuffer
* quiet: set to 'TRUE' to disable debug output
*/
static void GetTagSamplesFor14443bDemod() {
bool gotFrame = FALSE;
int lastRxCounter = ISO14443B_DMA_BUFFER_SIZE;
int max = 0, ci = 0, cq = 0, samples = 0;
uint32_t time_0 = 0, time_stop = 0;
BigBuf_free();
// Set up the demodulator for tag -> reader responses.
DemodInit(BigBuf_malloc(MAX_FRAME_SIZE));
// The DMA buffer, used to stream samples from the FPGA
int8_t *dmaBuf = (int8_t*) BigBuf_malloc(ISO14443B_DMA_BUFFER_SIZE);
int8_t *upTo = dmaBuf;
// Setup and start DMA.
if ( !FpgaSetupSscDma((uint8_t*) dmaBuf, ISO14443B_DMA_BUFFER_SIZE) ){
if (MF_DBGLEVEL > 1) Dbprintf("FpgaSetupSscDma failed. Exiting");
return;
}
time_0 = GetCountSspClk();
// And put the FPGA in the appropriate mode
FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ);
while( !BUTTON_PRESS() ) {
WDT_HIT();
int behindBy = lastRxCounter - AT91C_BASE_PDC_SSC->PDC_RCR;
if(behindBy > max) max = behindBy;
// rx counter - dma counter? (how much?) & (mod) dma buff / 2. (since 2bytes at the time is read)
while(((lastRxCounter - AT91C_BASE_PDC_SSC->PDC_RCR) & (ISO14443B_DMA_BUFFER_SIZE-1)) > 2) {
ci = upTo[0];
cq = upTo[1];
upTo += 2;
samples += 2;
// restart DMA buffer to receive again.
if(upTo >= dmaBuf + ISO14443B_DMA_BUFFER_SIZE) {
upTo = dmaBuf;
AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) upTo;
AT91C_BASE_PDC_SSC->PDC_RNCR = ISO14443B_DMA_BUFFER_SIZE;
}
lastRxCounter -= 2;
if(lastRxCounter <= 0)
lastRxCounter += ISO14443B_DMA_BUFFER_SIZE;
// is this | 0x01 the error? & 0xfe in https://github.com/Proxmark/proxmark3/issues/103
//gotFrame = Handle14443bTagSamplesDemod(ci & 0xfe, cq & 0xfe);
gotFrame = Handle14443bTagSamplesDemod(ci, cq);
if ( gotFrame ) break;
LED_A_INV();
}
time_stop = GetCountSspClk() - time_0;
if(time_stop > iso14b_timeout || gotFrame) break;
}
FpgaDisableSscDma();
if (MF_DBGLEVEL >= 3) {
Dbprintf("max behindby = %d, samples = %d, gotFrame = %s, Demod.state = %d, Demod.len = %u",
max,
samples,
(gotFrame) ? "true" : "false",
Demod.state,
Demod.len
);
}
if ( Demod.len > 0 )
LogTrace(Demod.output, Demod.len, Demod.startTime, Demod.endTime, NULL, FALSE);
}
//-----------------------------------------------------------------------------
// Transmit the command (to the tag) that was placed in ToSend[].
//-----------------------------------------------------------------------------
static void TransmitFor14443b_AsReader(void) {
FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_TX | FPGA_HF_READER_TX_SHALLOW_MOD);
SpinDelay(20);
int c;
// we could been in following mode:
// FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ
// if its second call or more
// What does this loop do? Is it TR1?
for(c = 0; c < 10;) {
if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
AT91C_BASE_SSC->SSC_THR = 0xFF;
++c;
}
}
// Send frame loop
for(c = 0; c < ToSendMax;) {
if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
AT91C_BASE_SSC->SSC_THR = ToSend[c];
++c;
}
}
WDT_HIT();
}
//-----------------------------------------------------------------------------
// Code a layer 2 command (string of octets, including CRC) into ToSend[],
// so that it is ready to transmit to the tag using TransmitFor14443b().
//-----------------------------------------------------------------------------
static void CodeIso14443bAsReader(const uint8_t *cmd, int len)
{
/*
* Reader data transmission:
* - no modulation ONES
* - SOF
* - Command, data and CRC_B
* - EOF
* - no modulation ONES
*
* 1 ETU == 1 BIT!
* TR0 - 8 ETUS minimum.
*/
int i;
uint8_t b;
ToSendReset();
// Send SOF
// 10-11 ETUs of ZERO
for(i = 0; i < 10; ++i) ToSendStuffBit(0);
// 2-3 ETUs of ONE
ToSendStuffBit(1);
ToSendStuffBit(1);
ToSendStuffBit(1);
// Sending cmd, LSB
// from here we add BITS
for(i = 0; i < len; ++i) {
// Start bit
ToSendStuffBit(0);
// Data bits
b = cmd[i];
if ( b & 1 ) ToSendStuffBit(1); else ToSendStuffBit(0);
if ( (b>>1) & 1) ToSendStuffBit(1); else ToSendStuffBit(0);
if ( (b>>2) & 1) ToSendStuffBit(1); else ToSendStuffBit(0);
if ( (b>>3) & 1) ToSendStuffBit(1); else ToSendStuffBit(0);
if ( (b>>4) & 1) ToSendStuffBit(1); else ToSendStuffBit(0);
if ( (b>>5) & 1) ToSendStuffBit(1); else ToSendStuffBit(0);
if ( (b>>6) & 1) ToSendStuffBit(1); else ToSendStuffBit(0);
if ( (b>>7) & 1) ToSendStuffBit(1); else ToSendStuffBit(0);
// Stop bit
ToSendStuffBit(1);
// EGT extra guard time
// For PCD it ranges 0-57us (1etu = 9us)
ToSendStuffBit(1);
ToSendStuffBit(1);
ToSendStuffBit(1);
}
// Send EOF
// 10-11 ETUs of ZERO
for(i = 0; i < 10; ++i) ToSendStuffBit(0);
// Transition time. TR0 - guard time
// 8ETUS minum?
// Per specification, Subcarrier must be stopped no later than 2 ETUs after EOF.
for(i = 0; i < 40 ; ++i) ToSendStuffBit(1);
// TR1 - Synchronization time
// Convert from last character reference to length
++ToSendMax;
}
/**
Convenience function to encode, transmit and trace iso 14443b comms
**/
static void CodeAndTransmit14443bAsReader(const uint8_t *cmd, int len) {
CodeIso14443bAsReader(cmd, len);
uint32_t time_start = GetCountSspClk();
TransmitFor14443b_AsReader();
if(trigger) LED_A_ON();
LogTrace(cmd, len, time_start, GetCountSspClk()-time_start, NULL, TRUE);
}
/* Sends an APDU to the tag
* TODO: check CRC and preamble
*/
uint8_t iso14443b_apdu(uint8_t const *message, size_t message_length, uint8_t *response)
{
uint8_t crc[2] = {0x00, 0x00};
uint8_t message_frame[message_length + 4];
// PCB
message_frame[0] = 0x0A | pcb_blocknum;
pcb_blocknum ^= 1;
// CID
message_frame[1] = 0;
// INF
memcpy(message_frame + 2, message, message_length);
// EDC (CRC)
ComputeCrc14443(CRC_14443_B, message_frame, message_length + 2, &message_frame[message_length + 2], &message_frame[message_length + 3]);
// send
CodeAndTransmit14443bAsReader(message_frame, message_length + 4); //no
// get response
GetTagSamplesFor14443bDemod(); //no
if(Demod.len < 3)
return 0;
// VALIDATE CRC
ComputeCrc14443(CRC_14443_B, Demod.output, Demod.len-2, &crc[0], &crc[1]);
if ( crc[0] != Demod.output[Demod.len-2] || crc[1] != Demod.output[Demod.len-1] )
return 0;
// copy response contents
if(response != NULL)
memcpy(response, Demod.output, Demod.len);
return Demod.len;
}
/**
* SRx Initialise.
*/
uint8_t iso14443b_select_srx_card(iso14b_card_select_t *card )
{
// INITIATE command: wake up the tag using the INITIATE
static const uint8_t init_srx[] = { ISO14443B_INITIATE, 0x00, 0x97, 0x5b };
// SELECT command (with space for CRC)
uint8_t select_srx[] = { ISO14443B_SELECT, 0x00, 0x00, 0x00};
// temp to calc crc.
uint8_t crc[2] = {0x00, 0x00};
CodeAndTransmit14443bAsReader(init_srx, sizeof(init_srx));
GetTagSamplesFor14443bDemod(); //no
if (Demod.len == 0) return 2;
// Randomly generated Chip ID
if (card) card->chipid = Demod.output[0];
select_srx[1] = Demod.output[0];
ComputeCrc14443(CRC_14443_B, select_srx, 2, &select_srx[2], &select_srx[3]);
CodeAndTransmit14443bAsReader(select_srx, sizeof(select_srx));
GetTagSamplesFor14443bDemod(); //no
if (Demod.len != 3) return 2;
// Check the CRC of the answer:
ComputeCrc14443(CRC_14443_B, Demod.output, Demod.len-2 , &crc[0], &crc[1]);
if(crc[0] != Demod.output[1] || crc[1] != Demod.output[2]) return 3;
// Check response from the tag: should be the same UID as the command we just sent:
if (select_srx[1] != Demod.output[0]) return 1;
// First get the tag's UID:
select_srx[0] = ISO14443B_GET_UID;
ComputeCrc14443(CRC_14443_B, select_srx, 1 , &select_srx[1], &select_srx[2]);
CodeAndTransmit14443bAsReader(select_srx, 3); // Only first three bytes for this one
GetTagSamplesFor14443bDemod(); //no
if (Demod.len != 10) return 2;
// The check the CRC of the answer
ComputeCrc14443(CRC_14443_B, Demod.output, Demod.len-2, &crc[0], &crc[1]);
if(crc[0] != Demod.output[8] || crc[1] != Demod.output[9]) return 3;
if (card) {
card->uidlen = 8;
memcpy(card->uid, Demod.output, 8);
}
return 0;
}
/* Perform the ISO 14443 B Card Selection procedure
* Currently does NOT do any collision handling.
* It expects 0-1 cards in the device's range.
* TODO: Support multiple cards (perform anticollision)
* TODO: Verify CRC checksums
*/
uint8_t iso14443b_select_card(iso14b_card_select_t *card )
{
// WUPB command (including CRC)
// Note: WUPB wakes up all tags, REQB doesn't wake up tags in HALT state
static const uint8_t wupb[] = { ISO14443B_REQB, 0x00, 0x08, 0x39, 0x73 };
// ATTRIB command (with space for CRC)
uint8_t attrib[] = { ISO14443B_ATTRIB, 0x00, 0x00, 0x00, 0x00, 0x00, 0x08, 0x00, 0x00, 0x00, 0x00};
// temp to calc crc.
uint8_t crc[2] = {0x00, 0x00};
// first, wake up the tag
CodeAndTransmit14443bAsReader(wupb, sizeof(wupb));
GetTagSamplesFor14443bDemod(); //select_card
// ATQB too short?
if (Demod.len < 14) return 2;
// VALIDATE CRC
ComputeCrc14443(CRC_14443_B, Demod.output, Demod.len-2, &crc[0], &crc[1]);
if ( crc[0] != Demod.output[12] || crc[1] != Demod.output[13] )
return 3;
if (card) {
card->uidlen = 4;
memcpy(card->uid, Demod.output+1, 4);
memcpy(card->atqb, Demod.output+5, 7);
}
// copy the PUPI to ATTRIB ( PUPI == UID )
memcpy(attrib + 1, Demod.output + 1, 4);
// copy the protocol info from ATQB (Protocol Info -> Protocol_Type) into ATTRIB (Param 3)
attrib[7] = Demod.output[10] & 0x0F;
ComputeCrc14443(CRC_14443_B, attrib, 9, attrib + 9, attrib + 10);
CodeAndTransmit14443bAsReader(attrib, sizeof(attrib));
GetTagSamplesFor14443bDemod();//select_card
// Answer to ATTRIB too short?
if(Demod.len < 3) return 2;
// VALIDATE CRC
ComputeCrc14443(CRC_14443_B, Demod.output, Demod.len-2, &crc[0], &crc[1]);
if ( crc[0] != Demod.output[1] || crc[1] != Demod.output[2] )
return 3;
// CID
if (card) card->cid = Demod.output[0];
uint8_t fwt = card->atqb[6]>>4;
if ( fwt < 16 ){
uint32_t fwt_time = (302 << fwt);
iso14b_set_timeout( fwt_time);
}
// reset PCB block number
pcb_blocknum = 0;
return 0;
}
// Set up ISO 14443 Type B communication (similar to iso14443a_setup)
// field is setup for "Sending as Reader"
void iso14443b_setup() {
if (MF_DBGLEVEL > 3) Dbprintf("iso1443b_setup Enter");
LEDsoff();
FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
//BigBuf_free();
//BigBuf_Clear_ext(false);
// Initialize Demod and Uart structs
DemodInit(BigBuf_malloc(MAX_FRAME_SIZE));
UartInit(BigBuf_malloc(MAX_FRAME_SIZE));
// connect Demodulated Signal to ADC:
SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
// Set up the synchronous serial port
FpgaSetupSsc();
// Signal field is on with the appropriate LED
FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_TX | FPGA_HF_READER_TX_SHALLOW_MOD);
SpinDelay(100);
// Start the timer
StartCountSspClk();
LED_D_ON();
if (MF_DBGLEVEL > 3) Dbprintf("iso1443b_setup Exit");
}
//-----------------------------------------------------------------------------
// Read a SRI512 ISO 14443B tag.
//
// SRI512 tags are just simple memory tags, here we're looking at making a dump
// of the contents of the memory. No anticollision algorithm is done, we assume
// we have a single tag in the field.
//
// I tried to be systematic and check every answer of the tag, every CRC, etc...
//-----------------------------------------------------------------------------
void ReadSTMemoryIso14443b(uint8_t numofblocks)
{
FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
// Make sure that we start from off, since the tags are stateful;
// confusing things will happen if we don't reset them between reads.
switch_off(); // before ReadStMemory
set_tracing(TRUE);
uint8_t i = 0x00;
SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
FpgaSetupSsc();
// Now give it time to spin up.
// Signal field is on with the appropriate LED
LED_D_ON();
FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ);
SpinDelay(20);
// First command: wake up the tag using the INITIATE command
uint8_t cmd1[] = {ISO14443B_INITIATE, 0x00, 0x97, 0x5b};
CodeAndTransmit14443bAsReader(cmd1, sizeof(cmd1)); //no
GetTagSamplesFor14443bDemod(); // no
if (Demod.len == 0) {
DbpString("No response from tag");
set_tracing(FALSE);
return;
} else {
Dbprintf("Randomly generated Chip ID (+ 2 byte CRC): %02x %02x %02x",
Demod.output[0], Demod.output[1], Demod.output[2]);
}
// There is a response, SELECT the uid
DbpString("Now SELECT tag:");
cmd1[0] = ISO14443B_SELECT; // 0x0E is SELECT
cmd1[1] = Demod.output[0];
ComputeCrc14443(CRC_14443_B, cmd1, 2, &cmd1[2], &cmd1[3]);
CodeAndTransmit14443bAsReader(cmd1, sizeof(cmd1)); //no
GetTagSamplesFor14443bDemod(); //no
if (Demod.len != 3) {
Dbprintf("Expected 3 bytes from tag, got %d", Demod.len);
set_tracing(FALSE);
return;
}
// Check the CRC of the answer:
ComputeCrc14443(CRC_14443_B, Demod.output, 1 , &cmd1[2], &cmd1[3]);
if(cmd1[2] != Demod.output[1] || cmd1[3] != Demod.output[2]) {
DbpString("CRC Error reading select response.");
set_tracing(FALSE);
return;
}
// Check response from the tag: should be the same UID as the command we just sent:
if (cmd1[1] != Demod.output[0]) {
Dbprintf("Bad response to SELECT from Tag, aborting: %02x %02x", cmd1[1], Demod.output[0]);
set_tracing(FALSE);
return;
}
// Tag is now selected,
// First get the tag's UID:
cmd1[0] = ISO14443B_GET_UID;
ComputeCrc14443(CRC_14443_B, cmd1, 1 , &cmd1[1], &cmd1[2]);
CodeAndTransmit14443bAsReader(cmd1, 3); // no -- Only first three bytes for this one
GetTagSamplesFor14443bDemod(); //no
if (Demod.len != 10) {
Dbprintf("Expected 10 bytes from tag, got %d", Demod.len);
set_tracing(FALSE);
return;
}
// The check the CRC of the answer (use cmd1 as temporary variable):
ComputeCrc14443(CRC_14443_B, Demod.output, 8, &cmd1[2], &cmd1[3]);
if(cmd1[2] != Demod.output[8] || cmd1[3] != Demod.output[9]) {
Dbprintf("CRC Error reading block! Expected: %04x got: %04x",
(cmd1[2]<<8)+cmd1[3], (Demod.output[8]<<8)+Demod.output[9]);
// Do not return;, let's go on... (we should retry, maybe ?)
}
Dbprintf("Tag UID (64 bits): %08x %08x",
(Demod.output[7]<<24) + (Demod.output[6]<<16) + (Demod.output[5]<<8) + Demod.output[4],
(Demod.output[3]<<24) + (Demod.output[2]<<16) + (Demod.output[1]<<8) + Demod.output[0]);
// Now loop to read all 16 blocks, address from 0 to last block
Dbprintf("Tag memory dump, block 0 to %d", numofblocks);
cmd1[0] = 0x08;
i = 0x00;
++numofblocks;
for (;;) {
if (i == numofblocks) {
DbpString("System area block (0xff):");
i = 0xff;
}
cmd1[1] = i;
ComputeCrc14443(CRC_14443_B, cmd1, 2, &cmd1[2], &cmd1[3]);
CodeAndTransmit14443bAsReader(cmd1, sizeof(cmd1)); //no
GetTagSamplesFor14443bDemod(); //no
if (Demod.len != 6) { // Check if we got an answer from the tag
DbpString("Expected 6 bytes from tag, got less...");
return;
}
// The check the CRC of the answer (use cmd1 as temporary variable):
ComputeCrc14443(CRC_14443_B, Demod.output, 4, &cmd1[2], &cmd1[3]);
if(cmd1[2] != Demod.output[4] || cmd1[3] != Demod.output[5]) {
Dbprintf("CRC Error reading block! Expected: %04x got: %04x",
(cmd1[2]<<8)+cmd1[3], (Demod.output[4]<<8)+Demod.output[5]);
// Do not return;, let's go on... (we should retry, maybe ?)
}
// Now print out the memory location:
Dbprintf("Address=%02x, Contents=%08x, CRC=%04x", i,
(Demod.output[3]<<24) + (Demod.output[2]<<16) + (Demod.output[1]<<8) + Demod.output[0],
(Demod.output[4]<<8)+Demod.output[5]);
if (i == 0xff) break;
++i;
}
set_tracing(FALSE);
}
static void iso1444b_setup_snoop(void){
if (MF_DBGLEVEL > 3) Dbprintf("iso1443b_setup_snoop Enter");
LEDsoff();
FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
BigBuf_free();
BigBuf_Clear_ext(false);
clear_trace();//setup snoop
set_tracing(TRUE);
// Initialize Demod and Uart structs
DemodInit(BigBuf_malloc(MAX_FRAME_SIZE));
UartInit(BigBuf_malloc(MAX_FRAME_SIZE));
if (MF_DBGLEVEL > 1) {
// Print debug information about the buffer sizes
Dbprintf("Snooping buffers initialized:");
Dbprintf(" Trace: %i bytes", BigBuf_max_traceLen());
Dbprintf(" Reader -> tag: %i bytes", MAX_FRAME_SIZE);
Dbprintf(" tag -> Reader: %i bytes", MAX_FRAME_SIZE);
Dbprintf(" DMA: %i bytes", ISO14443B_DMA_BUFFER_SIZE);
}
// connect Demodulated Signal to ADC:
SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
// Setup for the DMA.
FpgaSetupSsc();
// Set FPGA in the appropriate mode
FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ | FPGA_HF_READER_RX_XCORR_SNOOP);
SpinDelay(20);
// Start the SSP timer
StartCountSspClk();
if (MF_DBGLEVEL > 3) Dbprintf("iso1443b_setup_snoop Exit");
}
//=============================================================================
// Finally, the `sniffer' combines elements from both the reader and
// simulated tag, to show both sides of the conversation.
//=============================================================================
//-----------------------------------------------------------------------------
// 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.
//-----------------------------------------------------------------------------
/*
* Memory usage for this function, (within BigBuf)
* Last Received command (reader->tag) - MAX_FRAME_SIZE
* Last Received command (tag->reader) - MAX_FRAME_SIZE
* DMA Buffer - ISO14443B_DMA_BUFFER_SIZE
* Demodulated samples received - all the rest
*/
void RAMFUNC SnoopIso14443b(void) {
uint32_t time_0 = 0, time_start = 0, time_stop = 0;
// 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 = TRUE; // TODO: set and evaluate trigger condition
int ci, cq;
int maxBehindBy = 0;
//int behindBy = 0;
int lastRxCounter = ISO14443B_DMA_BUFFER_SIZE;
bool TagIsActive = FALSE;
bool ReaderIsActive = FALSE;
iso1444b_setup_snoop();
// The DMA buffer, used to stream samples from the FPGA
int8_t *dmaBuf = (int8_t*) BigBuf_malloc(ISO14443B_DMA_BUFFER_SIZE);
int8_t *upTo = dmaBuf;
// Setup and start DMA.
if ( !FpgaSetupSscDma((uint8_t*) dmaBuf, ISO14443B_DMA_BUFFER_SIZE) ){
if (MF_DBGLEVEL > 1) Dbprintf("FpgaSetupSscDma failed. Exiting");
BigBuf_free();
return;
}
time_0 = GetCountSspClk();
// And now we loop, receiving samples.
for(;;) {
WDT_HIT();
int behindBy = (lastRxCounter - AT91C_BASE_PDC_SSC->PDC_RCR) & (ISO14443B_DMA_BUFFER_SIZE-1);
if ( behindBy > maxBehindBy )
maxBehindBy = behindBy;
if ( behindBy < 2 ) continue;
ci = upTo[0];
cq = upTo[1];
upTo += 2;
lastRxCounter -= 2;
if (upTo >= dmaBuf + ISO14443B_DMA_BUFFER_SIZE) {
upTo = dmaBuf;
lastRxCounter += ISO14443B_DMA_BUFFER_SIZE;
AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) dmaBuf;
AT91C_BASE_PDC_SSC->PDC_RNCR = ISO14443B_DMA_BUFFER_SIZE;
WDT_HIT();
// TODO: understand whether we can increase/decrease as we want or not?
if ( behindBy > ( 9 * ISO14443B_DMA_BUFFER_SIZE/10) ) {
Dbprintf("blew circular buffer! behindBy=%d", behindBy);
break;
}
if(!tracing) {
DbpString("Trace full");
break;
}
if(BUTTON_PRESS()) {
DbpString("cancelled");
break;
}
}
if (!TagIsActive) {
LED_A_ON();
// no need to try decoding reader data if the tag is sending
if (Handle14443bReaderUartBit(ci & 0x01)) {
time_stop = (GetCountSspClk()-time_0);
if (triggered)
LogTrace(Uart.output, Uart.byteCnt, time_start, time_stop, NULL, TRUE);
/* And ready to receive another command. */
UartReset();
/* And also reset the demod code, which might have been */
/* false-triggered by the commands from the reader. */
DemodReset();
} else {
time_start = (GetCountSspClk()-time_0);
}
if (Handle14443bReaderUartBit(cq & 0x01)) {
time_stop = (GetCountSspClk()-time_0);
if (triggered)
LogTrace(Uart.output, Uart.byteCnt, time_start, time_stop, NULL, TRUE);
/* And ready to receive another command. */
UartReset();
/* And also reset the demod code, which might have been */
/* false-triggered by the commands from the reader. */
DemodReset();
} else {
time_start = (GetCountSspClk()-time_0);
}
ReaderIsActive = (Uart.state > STATE_GOT_FALLING_EDGE_OF_SOF);
LED_A_OFF();
}
if(!ReaderIsActive) {
// no need to try decoding tag data if the reader is sending - and we cannot afford the time
// is this | 0x01 the error? & 0xfe in https://github.com/Proxmark/proxmark3/issues/103
if(Handle14443bTagSamplesDemod(ci & 0xFE, cq & 0xFE)) {
time_stop = (GetCountSspClk()-time_0);
LogTrace(Demod.output, Demod.len, time_start, time_stop, NULL, FALSE);
triggered = TRUE;
// And ready to receive another response.
DemodReset();
} else {
time_start = (GetCountSspClk()-time_0);
}
TagIsActive = (Demod.state > DEMOD_GOT_FALLING_EDGE_OF_SOF);
}
}
switch_off(); // Snoop
DbpString("Snoop statistics:");
Dbprintf(" Max behind by: %i", maxBehindBy);
Dbprintf(" Uart State: %x ByteCount: %i ByteCountMax: %i", Uart.state, Uart.byteCnt, Uart.byteCntMax);
Dbprintf(" Trace length: %i", BigBuf_get_traceLen());
// free mem refs.
if ( dmaBuf ) dmaBuf = NULL;
if ( upTo ) upTo = NULL;
// Uart.byteCntMax should be set with ATQB value..
}
void iso14b_set_trigger(bool enable) {
trigger = enable;
}
/*
* Send raw command to tag ISO14443B
* @Input
* param flags enum ISO14B_COMMAND. (mifare.h)
* len len of buffer data
* data buffer with bytes to send
*
* @Output
* none
*
*/
void SendRawCommand14443B_Ex(UsbCommand *c)
{
iso14b_command_t param = c->arg[0];
size_t len = c->arg[1] & 0xffff;
uint8_t *cmd = c->d.asBytes;
uint8_t status = 0;
uint32_t sendlen = sizeof(iso14b_card_select_t);
uint8_t buf[USB_CMD_DATA_SIZE] = {0x00};
if (MF_DBGLEVEL > 3) Dbprintf("14b raw: param, %04x", param );
// turn on trigger (LED_A)
if ((param & ISO14B_REQUEST_TRIGGER) == ISO14B_REQUEST_TRIGGER)
iso14b_set_trigger(TRUE);
if ((param & ISO14B_CONNECT) == ISO14B_CONNECT) {
// Make sure that we start from off, since the tags are stateful;
// confusing things will happen if we don't reset them between reads.
//switch_off(); // before connect in raw
iso14443b_setup();
}
set_tracing(TRUE);
if ((param & ISO14B_SELECT_STD) == ISO14B_SELECT_STD) {
iso14b_card_select_t *card = (iso14b_card_select_t*)buf;
status = iso14443b_select_card(card);
cmd_send(CMD_ACK, status, sendlen, 0, buf, sendlen);
// 0: OK 2: attrib fail, 3:crc fail,
if ( status > 0 ) return;
}
if ((param & ISO14B_SELECT_SR) == ISO14B_SELECT_SR) {
iso14b_card_select_t *card = (iso14b_card_select_t*)buf;
status = iso14443b_select_srx_card(card);
cmd_send(CMD_ACK, status, sendlen, 0, buf, sendlen);
// 0: OK 2: attrib fail, 3:crc fail,
if ( status > 0 ) return;
}
if ((param & ISO14B_APDU) == ISO14B_APDU) {
status = iso14443b_apdu(cmd, len, buf);
cmd_send(CMD_ACK, status, status, 0, buf, status);
}
if ((param & ISO14B_RAW) == ISO14B_RAW) {
if((param & ISO14B_APPEND_CRC) == ISO14B_APPEND_CRC) {
AppendCrc14443b(cmd, len);
len += 2;
}
CodeAndTransmit14443bAsReader(cmd, len); // raw
GetTagSamplesFor14443bDemod(); // raw
sendlen = MIN(Demod.len, USB_CMD_DATA_SIZE);
status = (Demod.len > 0) ? 0 : 1;
cmd_send(CMD_ACK, status, sendlen, 0, Demod.output, sendlen);
}
// turn off trigger (LED_A)
if ((param & ISO14B_REQUEST_TRIGGER) == ISO14B_REQUEST_TRIGGER)
iso14b_set_trigger(FALSE);
// turn off antenna et al
// we don't send a HALT command.
if ((param & ISO14B_DISCONNECT) == ISO14B_DISCONNECT) {
if (MF_DBGLEVEL > 3) Dbprintf("disconnect");
switch_off(); // disconnect raw
} else {
//FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_TX | FPGA_HF_READER_TX_SHALLOW_MOD);
}
}
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