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proxmark3/armsrc/iso14443.c
roel@libnfc.org 81cd0474cb fixed a lot of simulation issues
2012-06-29 10:24:05 +00:00

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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 14443. This includes both the reader software and
// the `fake tag' modes. At the moment only the Type B modulation is
// supported.
//-----------------------------------------------------------------------------
#include "proxmark3.h"
#include "apps.h"
#include "util.h"
#include "string.h"
#include "iso14443crc.h"
//static void GetSamplesFor14443(int weTx, int n);
#define DEMOD_TRACE_SIZE 4096
#define READER_TAG_BUFFER_SIZE 2048
#define TAG_READER_BUFFER_SIZE 2048
#define DEMOD_DMA_BUFFER_SIZE 1024
//=============================================================================
// 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.
//=============================================================================
//-----------------------------------------------------------------------------
// 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)
{
int i;
ToSendReset();
// Transmit a burst of ones, as the initial thing that lets the
// reader get phase sync. This (TR1) must be > 80/fs, per spec,
// but tag that I've tried (a Paypass) exceeds that by a fair bit,
// so I will too.
for(i = 0; i < 20; i++) {
ToSendStuffBit(1);
ToSendStuffBit(1);
ToSendStuffBit(1);
ToSendStuffBit(1);
}
// Send SOF.
for(i = 0; i < 10; i++) {
ToSendStuffBit(0);
ToSendStuffBit(0);
ToSendStuffBit(0);
ToSendStuffBit(0);
}
for(i = 0; i < 2; i++) {
ToSendStuffBit(1);
ToSendStuffBit(1);
ToSendStuffBit(1);
ToSendStuffBit(1);
}
for(i = 0; i < len; i++) {
int j;
uint8_t b = cmd[i];
// Start bit
ToSendStuffBit(0);
ToSendStuffBit(0);
ToSendStuffBit(0);
ToSendStuffBit(0);
// Data bits
for(j = 0; j < 8; j++) {
if(b & 1) {
ToSendStuffBit(1);
ToSendStuffBit(1);
ToSendStuffBit(1);
ToSendStuffBit(1);
} else {
ToSendStuffBit(0);
ToSendStuffBit(0);
ToSendStuffBit(0);
ToSendStuffBit(0);
}
b >>= 1;
}
// Stop bit
ToSendStuffBit(1);
ToSendStuffBit(1);
ToSendStuffBit(1);
ToSendStuffBit(1);
}
// Send SOF.
for(i = 0; i < 10; i++) {
ToSendStuffBit(0);
ToSendStuffBit(0);
ToSendStuffBit(0);
ToSendStuffBit(0);
}
for(i = 0; i < 10; i++) {
ToSendStuffBit(1);
ToSendStuffBit(1);
ToSendStuffBit(1);
ToSendStuffBit(1);
}
// Convert from last byte pos to length
ToSendMax++;
// Add a few more for slop
ToSendMax += 2;
}
//-----------------------------------------------------------------------------
// 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_ERROR_WAIT
} state;
uint16_t shiftReg;
int bitCnt;
int byteCnt;
int byteCntMax;
int posCnt;
uint8_t *output;
} Uart;
/* Receive & handle a bit coming from the reader.
*
* 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 int Handle14443UartBit(int bit)
{
switch(Uart.state) {
case STATE_UNSYNCD:
LED_A_OFF();
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) {
if(bit) {
if(Uart.bitCnt >= 10) {
// 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_ERROR_WAIT;
}
} else {
// do nothing, keep waiting
}
Uart.bitCnt++;
}
if(Uart.posCnt >= 4) Uart.posCnt = 0;
if(Uart.bitCnt > 14) {
// Give up if we see too many zeros without
// a one, too.
Uart.state = STATE_ERROR_WAIT;
}
break;
case STATE_AWAITING_START_BIT:
Uart.posCnt++;
if(bit) {
if(Uart.posCnt > 25) {
// stayed high for too long between
// characters, error
Uart.state = STATE_ERROR_WAIT;
}
} else {
// falling edge, this starts the data byte
Uart.posCnt = 0;
Uart.bitCnt = 0;
Uart.shiftReg = 0;
Uart.state = STATE_RECEIVING_DATA;
LED_A_ON(); // Indicate we're receiving
}
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
Uart.posCnt = 0;
Uart.state = STATE_ERROR_WAIT;
} 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
return TRUE;
} else {
// this is an error
Uart.posCnt = 0;
Uart.state = STATE_ERROR_WAIT;
}
}
break;
case STATE_ERROR_WAIT:
// We're all screwed up, so wait a little while
// for whatever went wrong to finish, and then
// start over.
Uart.posCnt++;
if(Uart.posCnt > 10) {
Uart.state = STATE_UNSYNCD;
}
break;
default:
Uart.state = STATE_UNSYNCD;
break;
}
if (Uart.state == STATE_ERROR_WAIT) LED_A_OFF(); // Error
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 GetIso14443CommandFromReader(uint8_t *received, int *len, int maxLen)
{
uint8_t mask;
int i, bit;
// Set FPGA mode to "simulated ISO 14443 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);
// Now run a `software UART' on the stream of incoming samples.
Uart.output = received;
Uart.byteCntMax = maxLen;
Uart.state = STATE_UNSYNCD;
for(;;) {
WDT_HIT();
if(BUTTON_PRESS()) return FALSE;
if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
AT91C_BASE_SSC->SSC_THR = 0x00;
}
if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
uint8_t b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
mask = 0x80;
for(i = 0; i < 8; i++, mask >>= 1) {
bit = (b & mask);
if(Handle14443UartBit(bit)) {
*len = Uart.byteCnt;
return TRUE;
}
}
}
}
}
//-----------------------------------------------------------------------------
// Main loop of simulated tag: receive commands from reader, decide what
// response to send, and send it.
//-----------------------------------------------------------------------------
void SimulateIso14443Tag(void)
{
static const uint8_t cmd1[] = { 0x05, 0x00, 0x08, 0x39, 0x73 };
static const uint8_t response1[] = {
0x50, 0x82, 0x0d, 0xe1, 0x74, 0x20, 0x38, 0x19, 0x22,
0x00, 0x21, 0x85, 0x5e, 0xd7
};
uint8_t *resp;
int respLen;
uint8_t *resp1 = (((uint8_t *)BigBuf) + 800);
int resp1Len;
uint8_t *receivedCmd = (uint8_t *)BigBuf;
int len;
int i;
int cmdsRecvd = 0;
memset(receivedCmd, 0x44, 400);
CodeIso14443bAsTag(response1, sizeof(response1));
memcpy(resp1, ToSend, ToSendMax); resp1Len = ToSendMax;
// We need to listen to the high-frequency, peak-detected path.
SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
FpgaSetupSsc();
cmdsRecvd = 0;
for(;;) {
uint8_t b1, b2;
if(!GetIso14443CommandFromReader(receivedCmd, &len, 100)) {
Dbprintf("button pressed, received %d commands", cmdsRecvd);
break;
}
// Good, look at the command now.
if(len == sizeof(cmd1) && memcmp(receivedCmd, cmd1, len)==0) {
resp = resp1; respLen = resp1Len;
} else {
Dbprintf("new cmd from reader: len=%d, cmdsRecvd=%d", len, cmdsRecvd);
// And print whether the CRC fails, just for good measure
ComputeCrc14443(CRC_14443_B, receivedCmd, len-2, &b1, &b2);
if(b1 != receivedCmd[len-2] || b2 != receivedCmd[len-1]) {
// Not so good, try again.
DbpString("+++CRC fail");
} else {
DbpString("CRC passes");
}
break;
}
memset(receivedCmd, 0x44, 32);
cmdsRecvd++;
if(cmdsRecvd > 0x30) {
DbpString("many commands later...");
break;
}
if(respLen <= 0) continue;
// Modulate BPSK
// Signal field is off with the appropriate LED
LED_D_OFF();
FpgaWriteConfWord(
FPGA_MAJOR_MODE_HF_SIMULATOR | FPGA_HF_SIMULATOR_MODULATE_BPSK);
AT91C_BASE_SSC->SSC_THR = 0xff;
FpgaSetupSsc();
// Transmit the response.
i = 0;
for(;;) {
if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
uint8_t b = resp[i];
AT91C_BASE_SSC->SSC_THR = b;
i++;
if(i > respLen) {
break;
}
}
if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
volatile uint8_t b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
(void)b;
}
}
}
}
//=============================================================================
// 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.
//=============================================================================
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,
DEMOD_ERROR_WAIT
} state;
int bitCount;
int posCount;
int thisBit;
int metric;
int metricN;
uint16_t shiftReg;
uint8_t *output;
int len;
int sumI;
int sumQ;
} Demod;
/*
* Handles reception of a bit from the tag
*
* 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
*
*/
static RAMFUNC int Handle14443SamplesDemod(int ci, int cq)
{
int v;
// 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; \
} \
}
switch(Demod.state) {
case DEMOD_UNSYNCD:
v = ci;
if(v < 0) v = -v;
if(cq > 0) {
v += cq;
} else {
v -= cq;
}
if(v > 40) {
Demod.posCount = 0;
Demod.state = DEMOD_PHASE_REF_TRAINING;
Demod.sumI = 0;
Demod.sumQ = 0;
}
break;
case DEMOD_PHASE_REF_TRAINING:
if(Demod.posCount < 8) {
Demod.sumI += ci;
Demod.sumQ += cq;
} else if(Demod.posCount > 100) {
// error, waited too long
Demod.state = DEMOD_UNSYNCD;
} else {
MAKE_SOFT_DECISION();
if(v < 0) {
Demod.state = DEMOD_AWAITING_FALLING_EDGE_OF_SOF;
Demod.posCount = 0;
}
}
Demod.posCount++;
break;
case DEMOD_AWAITING_FALLING_EDGE_OF_SOF:
MAKE_SOFT_DECISION();
if(v < 0) {
Demod.state = DEMOD_GOT_FALLING_EDGE_OF_SOF;
Demod.posCount = 0;
} else {
if(Demod.posCount > 100) {
Demod.state = DEMOD_UNSYNCD;
}
}
Demod.posCount++;
break;
case DEMOD_GOT_FALLING_EDGE_OF_SOF:
MAKE_SOFT_DECISION();
if(v > 0) {
if(Demod.posCount < 12) {
Demod.state = DEMOD_UNSYNCD;
} else {
LED_C_ON(); // Got SOF
Demod.state = DEMOD_AWAITING_START_BIT;
Demod.posCount = 0;
Demod.len = 0;
Demod.metricN = 0;
Demod.metric = 0;
}
} else {
if(Demod.posCount > 100) {
Demod.state = DEMOD_UNSYNCD;
}
}
Demod.posCount++;
break;
case DEMOD_AWAITING_START_BIT:
MAKE_SOFT_DECISION();
if(v > 0) {
if(Demod.posCount > 10) {
Demod.state = DEMOD_UNSYNCD;
}
} else {
Demod.bitCount = 0;
Demod.posCount = 1;
Demod.thisBit = v;
Demod.shiftReg = 0;
Demod.state = DEMOD_RECEIVING_DATA;
}
break;
case DEMOD_RECEIVING_DATA:
MAKE_SOFT_DECISION();
if(Demod.posCount == 0) {
Demod.thisBit = v;
Demod.posCount = 1;
} else {
Demod.thisBit += v;
if(Demod.thisBit > 0) {
Demod.metric += Demod.thisBit;
} else {
Demod.metric -= Demod.thisBit;
}
(Demod.metricN)++;
Demod.shiftReg >>= 1;
if(Demod.thisBit > 0) {
Demod.shiftReg |= 0x200;
}
Demod.bitCount++;
if(Demod.bitCount == 10) {
uint16_t s = Demod.shiftReg;
if((s & 0x200) && !(s & 0x001)) {
uint8_t b = (s >> 1);
Demod.output[Demod.len] = b;
Demod.len++;
Demod.state = DEMOD_AWAITING_START_BIT;
} else if(s == 0x000) {
// This is EOF
LED_C_OFF();
return TRUE;
Demod.state = DEMOD_UNSYNCD;
} else {
Demod.state = DEMOD_UNSYNCD;
}
}
Demod.posCount = 0;
}
break;
default:
Demod.state = DEMOD_UNSYNCD;
break;
}
if (Demod.state == DEMOD_UNSYNCD) LED_C_OFF(); // Not synchronized...
return FALSE;
}
/*
* Demodulate the samples we received from the tag
* weTx: set to 'TRUE' if we behave like a reader
* set to 'FALSE' if we behave like a snooper
* quiet: set to 'TRUE' to disable debug output
*/
static void GetSamplesFor14443Demod(int weTx, int n, int quiet)
{
int max = 0;
int gotFrame = FALSE;
//# define DMA_BUFFER_SIZE 8
int8_t *dmaBuf;
int lastRxCounter;
int8_t *upTo;
int ci, cq;
int samples = 0;
// Clear out the state of the "UART" that receives from the tag.
memset(BigBuf, 0x44, 400);
Demod.output = (uint8_t *)BigBuf;
Demod.len = 0;
Demod.state = DEMOD_UNSYNCD;
// And the UART that receives from the reader
Uart.output = (((uint8_t *)BigBuf) + 1024);
Uart.byteCntMax = 100;
Uart.state = STATE_UNSYNCD;
// Setup for the DMA.
dmaBuf = (int8_t *)(BigBuf + 32);
upTo = dmaBuf;
lastRxCounter = DEMOD_DMA_BUFFER_SIZE;
FpgaSetupSscDma((uint8_t *)dmaBuf, DEMOD_DMA_BUFFER_SIZE);
// Signal field is ON with the appropriate LED:
if (weTx) LED_D_ON(); else LED_D_OFF();
// And put the FPGA in the appropriate mode
FpgaWriteConfWord(
FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ |
(weTx ? 0 : FPGA_HF_READER_RX_XCORR_SNOOP));
for(;;) {
int behindBy = lastRxCounter - AT91C_BASE_PDC_SSC->PDC_RCR;
if(behindBy > max) max = behindBy;
while(((lastRxCounter-AT91C_BASE_PDC_SSC->PDC_RCR) & (DEMOD_DMA_BUFFER_SIZE-1))
> 2)
{
ci = upTo[0];
cq = upTo[1];
upTo += 2;
if(upTo - dmaBuf > DEMOD_DMA_BUFFER_SIZE) {
upTo -= DEMOD_DMA_BUFFER_SIZE;
AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) upTo;
AT91C_BASE_PDC_SSC->PDC_RNCR = DEMOD_DMA_BUFFER_SIZE;
}
lastRxCounter -= 2;
if(lastRxCounter <= 0) {
lastRxCounter += DEMOD_DMA_BUFFER_SIZE;
}
samples += 2;
Handle14443UartBit(1);
Handle14443UartBit(1);
if(Handle14443SamplesDemod(ci, cq)) {
gotFrame = 1;
}
}
if(samples > 2000) {
break;
}
}
AT91C_BASE_PDC_SSC->PDC_PTCR = AT91C_PDC_RXTDIS;
if (!quiet) Dbprintf("%x %x %x", max, gotFrame, Demod.len);
}
//-----------------------------------------------------------------------------
// Read the tag's response. We just receive a stream of slightly-processed
// samples from the FPGA, which we will later do some signal processing on,
// to get the bits.
//-----------------------------------------------------------------------------
/*static void GetSamplesFor14443(int weTx, int n)
{
uint8_t *dest = (uint8_t *)BigBuf;
int c;
FpgaWriteConfWord(
FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ |
(weTx ? 0 : FPGA_HF_READER_RX_XCORR_SNOOP));
c = 0;
for(;;) {
if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
AT91C_BASE_SSC->SSC_THR = 0x43;
}
if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
int8_t b;
b = (int8_t)AT91C_BASE_SSC->SSC_RHR;
dest[c++] = (uint8_t)b;
if(c >= n) {
break;
}
}
}
}*/
//-----------------------------------------------------------------------------
// Transmit the command (to the tag) that was placed in ToSend[].
//-----------------------------------------------------------------------------
static void TransmitFor14443(void)
{
int c;
FpgaSetupSsc();
while(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
AT91C_BASE_SSC->SSC_THR = 0xff;
}
// Signal field is ON with the appropriate Red LED
LED_D_ON();
// Signal we are transmitting with the Green LED
LED_B_ON();
FpgaWriteConfWord(
FPGA_MAJOR_MODE_HF_READER_TX | FPGA_HF_READER_TX_SHALLOW_MOD);
for(c = 0; c < 10;) {
if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
AT91C_BASE_SSC->SSC_THR = 0xff;
c++;
}
if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
volatile uint32_t r = AT91C_BASE_SSC->SSC_RHR;
(void)r;
}
WDT_HIT();
}
c = 0;
for(;;) {
if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
AT91C_BASE_SSC->SSC_THR = ToSend[c];
c++;
if(c >= ToSendMax) {
break;
}
}
if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
volatile uint32_t r = AT91C_BASE_SSC->SSC_RHR;
(void)r;
}
WDT_HIT();
}
LED_B_OFF(); // Finished sending
}
//-----------------------------------------------------------------------------
// Code a layer 2 command (string of octets, including CRC) into ToSend[],
// so that it is ready to transmit to the tag using TransmitFor14443().
//-----------------------------------------------------------------------------
void CodeIso14443bAsReader(const uint8_t *cmd, int len)
{
int i, j;
uint8_t b;
ToSendReset();
// Establish initial reference level
for(i = 0; i < 40; i++) {
ToSendStuffBit(1);
}
// Send SOF
for(i = 0; i < 10; i++) {
ToSendStuffBit(0);
}
for(i = 0; i < len; i++) {
// Stop bits/EGT
ToSendStuffBit(1);
ToSendStuffBit(1);
// Start bit
ToSendStuffBit(0);
// Data bits
b = cmd[i];
for(j = 0; j < 8; j++) {
if(b & 1) {
ToSendStuffBit(1);
} else {
ToSendStuffBit(0);
}
b >>= 1;
}
}
// Send EOF
ToSendStuffBit(1);
for(i = 0; i < 10; i++) {
ToSendStuffBit(0);
}
for(i = 0; i < 8; i++) {
ToSendStuffBit(1);
}
// And then a little more, to make sure that the last character makes
// it out before we switch to rx mode.
for(i = 0; i < 24; i++) {
ToSendStuffBit(1);
}
// Convert from last character reference to length
ToSendMax++;
}
//-----------------------------------------------------------------------------
// Read an ISO 14443 tag. We send it some set of commands, and record the
// responses.
// The command name is misleading, it actually decodes the reponse in HEX
// into the output buffer (read the result using hexsamples, not hisamples)
//-----------------------------------------------------------------------------
void AcquireRawAdcSamplesIso14443(uint32_t parameter)
{
uint8_t cmd1[] = { 0x05, 0x00, 0x08, 0x39, 0x73 };
// Make sure that we start from off, since the tags are stateful;
// confusing things will happen if we don't reset them between reads.
FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
LED_D_OFF();
SpinDelay(200);
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(200);
CodeIso14443bAsReader(cmd1, sizeof(cmd1));
TransmitFor14443();
// LED_A_ON();
GetSamplesFor14443Demod(TRUE, 2000, FALSE);
// LED_A_OFF();
}
//-----------------------------------------------------------------------------
// Read a SRI512 ISO 14443 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 ReadSRI512Iso14443(uint32_t parameter)
{
ReadSTMemoryIso14443(parameter,0x0F);
}
void ReadSRIX4KIso14443(uint32_t parameter)
{
ReadSTMemoryIso14443(parameter,0x7F);
}
void ReadSTMemoryIso14443(uint32_t parameter,uint32_t dwLast)
{
uint8_t i = 0x00;
// Make sure that we start from off, since the tags are stateful;
// confusing things will happen if we don't reset them between reads.
LED_D_OFF();
FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
SpinDelay(200);
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(200);
// First command: wake up the tag using the INITIATE command
uint8_t cmd1[] = { 0x06, 0x00, 0x97, 0x5b};
CodeIso14443bAsReader(cmd1, sizeof(cmd1));
TransmitFor14443();
// LED_A_ON();
GetSamplesFor14443Demod(TRUE, 2000,TRUE);
// LED_A_OFF();
if (Demod.len == 0) {
DbpString("No response from tag");
return;
} else {
Dbprintf("Randomly generated UID from tag (+ 2 byte CRC): %x %x %x",
Demod.output[0], Demod.output[1],Demod.output[2]);
}
// There is a response, SELECT the uid
DbpString("Now SELECT tag:");
cmd1[0] = 0x0E; // 0x0E is SELECT
cmd1[1] = Demod.output[0];
ComputeCrc14443(CRC_14443_B, cmd1, 2, &cmd1[2], &cmd1[3]);
CodeIso14443bAsReader(cmd1, sizeof(cmd1));
TransmitFor14443();
// LED_A_ON();
GetSamplesFor14443Demod(TRUE, 2000,TRUE);
// LED_A_OFF();
if (Demod.len != 3) {
Dbprintf("Expected 3 bytes from tag, got %d", Demod.len);
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.");
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: %x %x", cmd1[1], Demod.output[0]);
return;
}
// Tag is now selected,
// First get the tag's UID:
cmd1[0] = 0x0B;
ComputeCrc14443(CRC_14443_B, cmd1, 1 , &cmd1[1], &cmd1[2]);
CodeIso14443bAsReader(cmd1, 3); // Only first three bytes for this one
TransmitFor14443();
// LED_A_ON();
GetSamplesFor14443Demod(TRUE, 2000,TRUE);
// LED_A_OFF();
if (Demod.len != 10) {
Dbprintf("Expected 10 bytes from tag, got %d", Demod.len);
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! - Below: expected, got %x %x",
(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 15
DbpString("Tag memory dump, block 0 to 15");
cmd1[0] = 0x08;
i = 0x00;
dwLast++;
for (;;) {
if (i == dwLast) {
DbpString("System area block (0xff):");
i = 0xff;
}
cmd1[1] = i;
ComputeCrc14443(CRC_14443_B, cmd1, 2, &cmd1[2], &cmd1[3]);
CodeIso14443bAsReader(cmd1, sizeof(cmd1));
TransmitFor14443();
// LED_A_ON();
GetSamplesFor14443Demod(TRUE, 2000,TRUE);
// LED_A_OFF();
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! - Below: expected, got %x %x",
(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=%x, Contents=%x, CRC=%x", 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++;
}
}
//=============================================================================
// 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)
* 0-4095 : Demodulated samples receive (4096 bytes) - DEMOD_TRACE_SIZE
* 4096-6143 : Last Received command, 2048 bytes (reader->tag) - READER_TAG_BUFFER_SIZE
* 6144-8191 : Last Received command, 2048 bytes(tag->reader) - TAG_READER_BUFFER_SIZE
* 8192-9215 : DMA Buffer, 1024 bytes (samples) - DEMOD_DMA_BUFFER_SIZE
*/
void RAMFUNC SnoopIso14443(void)
{
// 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;
// The command (reader -> tag) that we're working on receiving.
uint8_t *receivedCmd = (uint8_t *)(BigBuf) + DEMOD_TRACE_SIZE;
// The response (tag -> reader) that we're working on receiving.
uint8_t *receivedResponse = (uint8_t *)(BigBuf) + DEMOD_TRACE_SIZE + READER_TAG_BUFFER_SIZE;
// 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;
int traceLen = 0;
// The DMA buffer, used to stream samples from the FPGA.
int8_t *dmaBuf = (int8_t *)(BigBuf) + DEMOD_TRACE_SIZE + READER_TAG_BUFFER_SIZE + TAG_READER_BUFFER_SIZE;
int lastRxCounter;
int8_t *upTo;
int ci, cq;
int maxBehindBy = 0;
// Count of samples received so far, so that we can include timing
// information in the trace buffer.
int samples = 0;
// Initialize the trace buffer
memset(trace, 0x44, DEMOD_TRACE_SIZE);
// Set up the demodulator for tag -> reader responses.
Demod.output = receivedResponse;
Demod.len = 0;
Demod.state = DEMOD_UNSYNCD;
// And the reader -> tag commands
memset(&Uart, 0, sizeof(Uart));
Uart.output = receivedCmd;
Uart.byteCntMax = 100;
Uart.state = STATE_UNSYNCD;
// Print some debug information about the buffer sizes
Dbprintf("Snooping buffers initialized:");
Dbprintf(" Trace: %i bytes", DEMOD_TRACE_SIZE);
Dbprintf(" Reader -> tag: %i bytes", READER_TAG_BUFFER_SIZE);
Dbprintf(" tag -> Reader: %i bytes", TAG_READER_BUFFER_SIZE);
Dbprintf(" DMA: %i bytes", DEMOD_DMA_BUFFER_SIZE);
// And put the FPGA in the appropriate mode
// Signal field is off with the appropriate LED
LED_D_OFF();
FpgaWriteConfWord(
FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ |
FPGA_HF_READER_RX_XCORR_SNOOP);
SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
// Setup for the DMA.
FpgaSetupSsc();
upTo = dmaBuf;
lastRxCounter = DEMOD_DMA_BUFFER_SIZE;
FpgaSetupSscDma((uint8_t *)dmaBuf, DEMOD_DMA_BUFFER_SIZE);
LED_A_ON();
// And now we loop, receiving samples.
for(;;) {
int behindBy = (lastRxCounter - AT91C_BASE_PDC_SSC->PDC_RCR) &
(DEMOD_DMA_BUFFER_SIZE-1);
if(behindBy > maxBehindBy) {
maxBehindBy = behindBy;
if(behindBy > (DEMOD_DMA_BUFFER_SIZE-2)) { // TODO: understand whether we can increase/decrease as we want or not?
Dbprintf("blew circular buffer! behindBy=0x%x", behindBy);
goto done;
}
}
if(behindBy < 2) continue;
ci = upTo[0];
cq = upTo[1];
upTo += 2;
lastRxCounter -= 2;
if(upTo - dmaBuf > DEMOD_DMA_BUFFER_SIZE) {
upTo -= DEMOD_DMA_BUFFER_SIZE;
lastRxCounter += DEMOD_DMA_BUFFER_SIZE;
AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) upTo;
AT91C_BASE_PDC_SSC->PDC_RNCR = DEMOD_DMA_BUFFER_SIZE;
}
samples += 2;
#define HANDLE_BIT_IF_BODY \
if(triggered) { \
trace[traceLen++] = ((samples >> 0) & 0xff); \
trace[traceLen++] = ((samples >> 8) & 0xff); \
trace[traceLen++] = ((samples >> 16) & 0xff); \
trace[traceLen++] = ((samples >> 24) & 0xff); \
trace[traceLen++] = 0; \
trace[traceLen++] = 0; \
trace[traceLen++] = 0; \
trace[traceLen++] = 0; \
trace[traceLen++] = Uart.byteCnt; \
memcpy(trace+traceLen, receivedCmd, Uart.byteCnt); \
traceLen += Uart.byteCnt; \
if(traceLen > 1000) break; \
} \
/* And ready to receive another command. */ \
memset(&Uart, 0, sizeof(Uart)); \
Uart.output = receivedCmd; \
Uart.byteCntMax = 100; \
Uart.state = STATE_UNSYNCD; \
/* And also reset the demod code, which might have been */ \
/* false-triggered by the commands from the reader. */ \
memset(&Demod, 0, sizeof(Demod)); \
Demod.output = receivedResponse; \
Demod.state = DEMOD_UNSYNCD; \
if(Handle14443UartBit(ci & 1)) {
HANDLE_BIT_IF_BODY
}
if(Handle14443UartBit(cq & 1)) {
HANDLE_BIT_IF_BODY
}
if(Handle14443SamplesDemod(ci, cq)) {
// timestamp, as a count of samples
trace[traceLen++] = ((samples >> 0) & 0xff);
trace[traceLen++] = ((samples >> 8) & 0xff);
trace[traceLen++] = ((samples >> 16) & 0xff);
trace[traceLen++] = 0x80 | ((samples >> 24) & 0xff);
// correlation metric (~signal strength estimate)
if(Demod.metricN != 0) {
Demod.metric /= Demod.metricN;
}
trace[traceLen++] = ((Demod.metric >> 0) & 0xff);
trace[traceLen++] = ((Demod.metric >> 8) & 0xff);
trace[traceLen++] = ((Demod.metric >> 16) & 0xff);
trace[traceLen++] = ((Demod.metric >> 24) & 0xff);
// length
trace[traceLen++] = Demod.len;
memcpy(trace+traceLen, receivedResponse, Demod.len);
traceLen += Demod.len;
if(traceLen > DEMOD_TRACE_SIZE) {
DbpString("Reached trace limit");
goto done;
}
triggered = TRUE;
LED_A_OFF();
LED_B_ON();
// And ready to receive another response.
memset(&Demod, 0, sizeof(Demod));
Demod.output = receivedResponse;
Demod.state = DEMOD_UNSYNCD;
}
WDT_HIT();
if(BUTTON_PRESS()) {
DbpString("cancelled");
goto done;
}
}
done:
LED_A_OFF();
LED_B_OFF();
LED_C_OFF();
AT91C_BASE_PDC_SSC->PDC_PTCR = AT91C_PDC_RXTDIS;
DbpString("Snoop statistics:");
Dbprintf(" Max behind by: %i", maxBehindBy);
Dbprintf(" Uart State: %x", Uart.state);
Dbprintf(" Uart ByteCnt: %i", Uart.byteCnt);
Dbprintf(" Uart ByteCntMax: %i", Uart.byteCntMax);
Dbprintf(" Trace length: %i", traceLen);
}
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