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[proxmark3-svn] / armsrc / iso14443b.c
1 //-----------------------------------------------------------------------------
2 // Jonathan Westhues, split Nov 2006
3 //
4 // This code is licensed to you under the terms of the GNU GPL, version 2 or,
5 // at your option, any later version. See the LICENSE.txt file for the text of
6 // the license.
7 //-----------------------------------------------------------------------------
8 // Routines to support ISO 14443B. This includes both the reader software and
9 // the `fake tag' modes.
10 //-----------------------------------------------------------------------------
11 #include "iso14443b.h"
12
13 #define RECEIVE_SAMPLES_TIMEOUT 50000
14 #define ISO14443B_DMA_BUFFER_SIZE 256
15
16 // Guard Time (per 14443-2)
17 #define TR0 0
18 // Synchronization time (per 14443-2)
19 #define TR1 0
20 // Frame Delay Time PICC to PCD (per 14443-3 Amendment 1)
21 #define TR2 0
22 static void switch_off(void);
23
24 // the block number for the ISO14443-4 PCB (used with APDUs)
25 static uint8_t pcb_blocknum = 0;
26
27 static uint32_t iso14b_timeout = RECEIVE_SAMPLES_TIMEOUT;
28 // param timeout is in ftw_
29 void iso14b_set_timeout(uint32_t timeout) {
30 // 9.4395us = 1etu.
31 // clock is about 1.5 us
32 iso14b_timeout = timeout;
33 if(MF_DBGLEVEL >= 2) Dbprintf("ISO14443B Timeout set to %ld fwt", iso14b_timeout);
34 }
35
36 static void switch_off(void){
37 if (MF_DBGLEVEL > 3) Dbprintf("switch_off");
38 FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
39 SpinDelay(100);
40 FpgaDisableSscDma();
41 set_tracing(FALSE);
42 LEDsoff();
43 }
44
45 //=============================================================================
46 // An ISO 14443 Type B tag. We listen for commands from the reader, using
47 // a UART kind of thing that's implemented in software. When we get a
48 // frame (i.e., a group of bytes between SOF and EOF), we check the CRC.
49 // If it's good, then we can do something appropriate with it, and send
50 // a response.
51 //=============================================================================
52
53
54 //-----------------------------------------------------------------------------
55 // The software UART that receives commands from the reader, and its state variables.
56 //-----------------------------------------------------------------------------
57 static struct {
58 enum {
59 STATE_UNSYNCD,
60 STATE_GOT_FALLING_EDGE_OF_SOF,
61 STATE_AWAITING_START_BIT,
62 STATE_RECEIVING_DATA
63 } state;
64 uint16_t shiftReg;
65 int bitCnt;
66 int byteCnt;
67 int byteCntMax;
68 int posCnt;
69 uint8_t *output;
70 } Uart;
71
72 static void UartReset() {
73 Uart.state = STATE_UNSYNCD;
74 Uart.shiftReg = 0;
75 Uart.bitCnt = 0;
76 Uart.byteCnt = 0;
77 Uart.byteCntMax = MAX_FRAME_SIZE;
78 Uart.posCnt = 0;
79 }
80
81 static void UartInit(uint8_t *data) {
82 Uart.output = data;
83 UartReset();
84 // memset(Uart.output, 0x00, MAX_FRAME_SIZE);
85 }
86
87 //-----------------------------------------------------------------------------
88 // The software Demod that receives commands from the tag, and its state variables.
89 //-----------------------------------------------------------------------------
90 static struct {
91 enum {
92 DEMOD_UNSYNCD,
93 DEMOD_PHASE_REF_TRAINING,
94 DEMOD_AWAITING_FALLING_EDGE_OF_SOF,
95 DEMOD_GOT_FALLING_EDGE_OF_SOF,
96 DEMOD_AWAITING_START_BIT,
97 DEMOD_RECEIVING_DATA
98 } state;
99 uint16_t bitCount;
100 int posCount;
101 int thisBit;
102 /* this had been used to add RSSI (Received Signal Strength Indication) to traces. Currently not implemented.
103 int metric;
104 int metricN;
105 */
106 uint16_t shiftReg;
107 uint8_t *output;
108 uint16_t len;
109 int sumI;
110 int sumQ;
111 uint32_t startTime, endTime;
112 } Demod;
113
114 // Clear out the state of the "UART" that receives from the tag.
115 static void DemodReset() {
116 Demod.state = DEMOD_UNSYNCD;
117 Demod.bitCount = 0;
118 Demod.posCount = 0;
119 Demod.thisBit = 0;
120 Demod.shiftReg = 0;
121 Demod.len = 0;
122 Demod.sumI = 0;
123 Demod.sumQ = 0;
124 Demod.startTime = 0;
125 Demod.endTime = 0;
126 }
127
128 static void DemodInit(uint8_t *data) {
129 Demod.output = data;
130 DemodReset();
131 // memset(Demod.output, 0x00, MAX_FRAME_SIZE);
132 }
133
134 void AppendCrc14443b(uint8_t* data, int len) {
135 ComputeCrc14443(CRC_14443_B, data, len, data+len, data+len+1);
136 }
137
138 //-----------------------------------------------------------------------------
139 // Code up a string of octets at layer 2 (including CRC, we don't generate
140 // that here) so that they can be transmitted to the reader. Doesn't transmit
141 // them yet, just leaves them ready to send in ToSend[].
142 //-----------------------------------------------------------------------------
143 static void CodeIso14443bAsTag(const uint8_t *cmd, int len) {
144 /* ISO 14443 B
145 *
146 * Reader to card | ASK - Amplitude Shift Keying Modulation (PCD to PICC for Type B) (NRZ-L encodig)
147 * Card to reader | BPSK - Binary Phase Shift Keying Modulation, (PICC to PCD for Type B)
148 *
149 * fc - carrier frequency 13.56mHz
150 * TR0 - Guard Time per 14443-2
151 * TR1 - Synchronization Time per 14443-2
152 * TR2 - PICC to PCD Frame Delay Time (per 14443-3 Amendment 1)
153 *
154 * Elementary Time Unit (ETU) is
155 * - 128 Carrier Cycles (9.4395 µS) = 8 Subcarrier Units
156 * - 1 ETU = 1 bit
157 * - 10 ETU = 1 startbit, 8 databits, 1 stopbit (10bits length)
158 * - startbit is a 0
159 * - stopbit is a 1
160 *
161 * Start of frame (SOF) is
162 * - [10-11] ETU of ZEROS, unmodulated time
163 * - [2-3] ETU of ONES,
164 *
165 * End of frame (EOF) is
166 * - [10-11] ETU of ZEROS, unmodulated time
167 *
168 * -TO VERIFY THIS BELOW-
169 * The mode FPGA_MAJOR_MODE_HF_SIMULATOR | FPGA_HF_SIMULATOR_MODULATE_BPSK which we use to simulate tag
170 * works like this:
171 * - A 1-bit input to the FPGA becomes 8 pulses at 847.5kHz (9.44µS)
172 * - A 0-bit input to the FPGA becomes an unmodulated time of 9.44µS
173 *
174 *
175 *
176 * Card sends data ub 847.e kHz subcarrier
177 * 848k = 9.44µS = 128 fc
178 * 424k = 18.88µS = 256 fc
179 * 212k = 37.76µS = 512 fc
180 * 106k = 75.52µS = 1024 fc
181 *
182 * Reader data transmission:
183 * - no modulation ONES
184 * - SOF
185 * - Command, data and CRC_B
186 * - EOF
187 * - no modulation ONES
188 *
189 * Card data transmission
190 * - TR1
191 * - SOF
192 * - data (each bytes is: 1startbit,8bits, 1stopbit)
193 * - CRC_B
194 * - EOF
195 *
196 * FPGA implementation :
197 * At this point only Type A is implemented. This means that we are using a
198 * bit rate of 106 kbit/s, or fc/128. Oversample by 4, which ought to make
199 * things practical for the ARM (fc/32, 423.8 kbits/s, ~50 kbytes/s)
200 *
201 */
202
203 // ToSendStuffBit, 40 calls
204 // 1 ETU = 1startbit, 1stopbit, 8databits == 10bits.
205 // 1 ETU = 10 * 4 == 40 stuffbits ( ETU_TAG_BIT )
206 int i,j;
207 uint8_t b;
208
209 ToSendReset();
210
211 // Transmit a burst of ones, as the initial thing that lets the
212 // reader get phase sync.
213 // This loop is TR1, per specification
214 // TR1 minimum must be > 80/fs
215 // TR1 maximum 200/fs
216 // 80/fs < TR1 < 200/fs
217 // 10 ETU < TR1 < 24 ETU
218
219 // Send SOF.
220 // 10-11 ETU * 4times samples ZEROS
221 for(i = 0; i < 10; i++) {
222 ToSendStuffBit(0);
223 ToSendStuffBit(0);
224 ToSendStuffBit(0);
225 ToSendStuffBit(0);
226 }
227
228 // 2-3 ETU * 4times samples ONES
229 for(i = 0; i < 3; i++) {
230 ToSendStuffBit(1);
231 ToSendStuffBit(1);
232 ToSendStuffBit(1);
233 ToSendStuffBit(1);
234 }
235
236 // data
237 for(i = 0; i < len; ++i) {
238
239 // Start bit
240 ToSendStuffBit(0);
241 ToSendStuffBit(0);
242 ToSendStuffBit(0);
243 ToSendStuffBit(0);
244
245 // Data bits
246 b = cmd[i];
247 for(j = 0; j < 8; ++j) {
248 if(b & 1) {
249 ToSendStuffBit(1);
250 ToSendStuffBit(1);
251 ToSendStuffBit(1);
252 ToSendStuffBit(1);
253 } else {
254 ToSendStuffBit(0);
255 ToSendStuffBit(0);
256 ToSendStuffBit(0);
257 ToSendStuffBit(0);
258 }
259 b >>= 1;
260 }
261
262 // Stop bit
263 ToSendStuffBit(1);
264 ToSendStuffBit(1);
265 ToSendStuffBit(1);
266 ToSendStuffBit(1);
267
268 // Extra Guard bit
269 // For PICC it ranges 0-18us (1etu = 9us)
270 ToSendStuffBit(1);
271 ToSendStuffBit(1);
272 ToSendStuffBit(1);
273 ToSendStuffBit(1);
274 }
275
276 // Send EOF.
277 // 10-11 ETU * 4 sample rate = ZEROS
278 for(i = 0; i < 10; i++) {
279 ToSendStuffBit(0);
280 ToSendStuffBit(0);
281 ToSendStuffBit(0);
282 ToSendStuffBit(0);
283 }
284
285 // why this?
286 for(i = 0; i < 40; i++) {
287 ToSendStuffBit(1);
288 ToSendStuffBit(1);
289 ToSendStuffBit(1);
290 ToSendStuffBit(1);
291 }
292
293 // Convert from last byte pos to length
294 ++ToSendMax;
295 }
296
297
298 /* Receive & handle a bit coming from the reader.
299 *
300 * This function is called 4 times per bit (every 2 subcarrier cycles).
301 * Subcarrier frequency fs is 848kHz, 1/fs = 1,18us, i.e. function is called every 2,36us
302 *
303 * LED handling:
304 * LED A -> ON once we have received the SOF and are expecting the rest.
305 * LED A -> OFF once we have received EOF or are in error state or unsynced
306 *
307 * Returns: true if we received a EOF
308 * false if we are still waiting for some more
309 */
310 static RAMFUNC int Handle14443bReaderUartBit(uint8_t bit) {
311 switch(Uart.state) {
312 case STATE_UNSYNCD:
313 if(!bit) {
314 // we went low, so this could be the beginning of an SOF
315 Uart.state = STATE_GOT_FALLING_EDGE_OF_SOF;
316 Uart.posCnt = 0;
317 Uart.bitCnt = 0;
318 }
319 break;
320
321 case STATE_GOT_FALLING_EDGE_OF_SOF:
322 Uart.posCnt++;
323 if(Uart.posCnt == 2) { // sample every 4 1/fs in the middle of a bit
324 if(bit) {
325 if(Uart.bitCnt > 9) {
326 // we've seen enough consecutive
327 // zeros that it's a valid SOF
328 Uart.posCnt = 0;
329 Uart.byteCnt = 0;
330 Uart.state = STATE_AWAITING_START_BIT;
331 LED_A_ON(); // Indicate we got a valid SOF
332 } else {
333 // didn't stay down long enough
334 // before going high, error
335 Uart.state = STATE_UNSYNCD;
336 }
337 } else {
338 // do nothing, keep waiting
339 }
340 Uart.bitCnt++;
341 }
342 if(Uart.posCnt >= 4) Uart.posCnt = 0;
343 if(Uart.bitCnt > 12) {
344 // Give up if we see too many zeros without
345 // a one, too.
346 LED_A_OFF();
347 Uart.state = STATE_UNSYNCD;
348 }
349 break;
350
351 case STATE_AWAITING_START_BIT:
352 Uart.posCnt++;
353 if(bit) {
354 if(Uart.posCnt > 50/2) { // max 57us between characters = 49 1/fs, max 3 etus after low phase of SOF = 24 1/fs
355 // stayed high for too long between
356 // characters, error
357 Uart.state = STATE_UNSYNCD;
358 }
359 } else {
360 // falling edge, this starts the data byte
361 Uart.posCnt = 0;
362 Uart.bitCnt = 0;
363 Uart.shiftReg = 0;
364 Uart.state = STATE_RECEIVING_DATA;
365 }
366 break;
367
368 case STATE_RECEIVING_DATA:
369 Uart.posCnt++;
370 if(Uart.posCnt == 2) {
371 // time to sample a bit
372 Uart.shiftReg >>= 1;
373 if(bit) {
374 Uart.shiftReg |= 0x200;
375 }
376 Uart.bitCnt++;
377 }
378 if(Uart.posCnt >= 4) {
379 Uart.posCnt = 0;
380 }
381 if(Uart.bitCnt == 10) {
382 if((Uart.shiftReg & 0x200) && !(Uart.shiftReg & 0x001))
383 {
384 // this is a data byte, with correct
385 // start and stop bits
386 Uart.output[Uart.byteCnt] = (Uart.shiftReg >> 1) & 0xff;
387 Uart.byteCnt++;
388
389 if(Uart.byteCnt >= Uart.byteCntMax) {
390 // Buffer overflowed, give up
391 LED_A_OFF();
392 Uart.state = STATE_UNSYNCD;
393 } else {
394 // so get the next byte now
395 Uart.posCnt = 0;
396 Uart.state = STATE_AWAITING_START_BIT;
397 }
398 } else if (Uart.shiftReg == 0x000) {
399 // this is an EOF byte
400 LED_A_OFF(); // Finished receiving
401 Uart.state = STATE_UNSYNCD;
402 if (Uart.byteCnt != 0) {
403 return TRUE;
404 }
405 } else {
406 // this is an error
407 LED_A_OFF();
408 Uart.state = STATE_UNSYNCD;
409 }
410 }
411 break;
412
413 default:
414 LED_A_OFF();
415 Uart.state = STATE_UNSYNCD;
416 break;
417 }
418
419 return FALSE;
420 }
421
422 //-----------------------------------------------------------------------------
423 // Receive a command (from the reader to us, where we are the simulated tag),
424 // and store it in the given buffer, up to the given maximum length. Keeps
425 // spinning, waiting for a well-framed command, until either we get one
426 // (returns TRUE) or someone presses the pushbutton on the board (FALSE).
427 //
428 // Assume that we're called with the SSC (to the FPGA) and ADC path set
429 // correctly.
430 //-----------------------------------------------------------------------------
431 static int GetIso14443bCommandFromReader(uint8_t *received, uint16_t *len) {
432 // Set FPGA mode to "simulated ISO 14443B tag", no modulation (listen
433 // only, since we are receiving, not transmitting).
434 // Signal field is off with the appropriate LED
435 LED_D_OFF();
436 FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_SIMULATOR | FPGA_HF_SIMULATOR_NO_MODULATION);
437
438 StartCountSspClk();
439
440 // Now run a `software UART' on the stream of incoming samples.
441 UartInit(received);
442
443 uint8_t mask, b = 0;
444 while( !BUTTON_PRESS() ) {
445 WDT_HIT();
446
447 if ( AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY ) {
448 b = (uint8_t) AT91C_BASE_SSC->SSC_RHR;
449 for ( mask = 0x80; mask != 0; mask >>= 1) {
450 if ( Handle14443bReaderUartBit(b & mask)) {
451 *len = Uart.byteCnt;
452 return TRUE;
453 }
454 }
455 }
456 }
457 return FALSE;
458 }
459
460
461 static void TransmitFor14443b_AsTag( uint8_t *response, uint16_t len) {
462
463 // Signal field is off with the appropriate LED
464 LED_D_OFF();
465
466 // Modulate BPSK
467 FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_SIMULATOR | FPGA_HF_SIMULATOR_MODULATE_BPSK);
468
469 // 8 ETU / 8bits. 8/4= 2 etus.
470 AT91C_BASE_SSC->SSC_THR = 0XFF;
471
472 FpgaSetupSsc();
473
474 // Transmit the response.
475 for(uint16_t i = 0; i < len;) {
476 if(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXRDY) {
477 AT91C_BASE_SSC->SSC_THR = response[i];
478 ++i;
479 }
480 }
481 }
482 //-----------------------------------------------------------------------------
483 // Main loop of simulated tag: receive commands from reader, decide what
484 // response to send, and send it.
485 //-----------------------------------------------------------------------------
486 void SimulateIso14443bTag(uint32_t pupi) {
487 // the only commands we understand is WUPB, AFI=0, Select All, N=1:
488 static const uint8_t cmd1[] = { ISO14443B_REQB, 0x00, 0x08, 0x39, 0x73 }; // WUPB
489 // ... and REQB, AFI=0, Normal Request, N=1:
490 static const uint8_t cmd2[] = { ISO14443B_REQB, 0x00, 0x00, 0x71, 0xFF }; // REQB
491 // ... and ATTRIB
492 static const uint8_t cmd4[] = { ISO14443B_ATTRIB, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff}; // ATTRIB
493
494 // ... if not PUPI/UID is supplied we always respond with ATQB, PUPI = 820de174, Application Data = 0x20381922,
495 // supports only 106kBit/s in both directions, max frame size = 32Bytes,
496 // supports ISO14443-4, FWI=8 (77ms), NAD supported, CID not supported:
497 uint8_t response1[] = {
498 0x50, 0x82, 0x0d, 0xe1, 0x74, 0x20, 0x38, 0x19, 0x22,
499 0x00, 0x21, 0x85, 0x5e, 0xd7
500 };
501 // response to HLTB and ATTRIB
502 static const uint8_t response2[] = {0x00, 0x78, 0xF0};
503
504 // PUPI/UID supplied
505 if ( pupi > 0 ) {
506 uint8_t len = sizeof(response1);
507 num_to_bytes(pupi, 4, response1+1);
508 ComputeCrc14443(CRC_14443_B, response1, len-2, response1+len-2, response1+len-1);
509 //print it..
510 }
511
512 uint16_t len, cmdsRecvd = 0;
513 uint8_t *receivedCmd = BigBuf_malloc(MAX_FRAME_SIZE);
514
515 uint8_t *resp1Code;
516 uint8_t *resp2Code;
517 uint16_t resp1CodeLen, resp2CodeLen;
518
519 // uint32_t time_0 = 0;
520 // uint32_t t2r_time = 0;
521 // uint32_t r2t_time = 0;
522
523 int cardSTATE = MFEMUL_NOFIELD;
524 int vHf = 0; // in mV
525
526 FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
527
528 // allocate command receive buffer
529 BigBuf_free();
530 BigBuf_Clear_ext(false);
531 clear_trace(); //sim
532 set_tracing(TRUE);
533
534 // connect Demodulated Signal to ADC:
535 SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
536
537 // Set up the synchronous serial port
538 FpgaSetupSsc();
539
540 // prepare the (only one) tag answer:
541 CodeIso14443bAsTag(response1, sizeof(response1));
542 resp1Code = BigBuf_malloc(ToSendMax);
543 resp1CodeLen = ToSendMax;
544 memcpy(resp1Code, ToSend, ToSendMax);
545
546
547 // prepare the (other) tag answer:
548 CodeIso14443bAsTag(response2, sizeof(response2));
549 resp2Code = BigBuf_malloc(ToSendMax);
550 resp2CodeLen = ToSendMax;
551 memcpy(resp2Code, ToSend, ToSendMax);
552
553
554 while (!BUTTON_PRESS() && !usb_poll_validate_length()) {
555 WDT_HIT();
556
557 // find reader field
558 if (cardSTATE == MFEMUL_NOFIELD) {
559 vHf = (MAX_ADC_HF_VOLTAGE * AvgAdc(ADC_CHAN_HF)) >> 10;
560 if ( vHf > MF_MINFIELDV )
561 cardSTATE = MFEMUL_IDLE;
562 }
563 if (cardSTATE == MFEMUL_NOFIELD) continue;
564
565
566 if (!GetIso14443bCommandFromReader(receivedCmd, &len)) {
567 Dbprintf("button pressed, received %d commands", cmdsRecvd);
568 break;
569 }
570
571 // REQ or WUP request in ANY state and WUP in HALTED state
572 if (len == 5 && (
573 (receivedCmd[0] == ISO14443B_REQB && cardSTATE != MFEMUL_HALTED) ||
574 receivedCmd[0] == ISO14443A_CMD_WUPA
575 )
576 ) {
577 TransmitFor14443b_AsTag( resp1Code, resp1CodeLen );
578 LogTrace(response1, sizeof(response1), 0, 0, NULL, FALSE);
579 cardSTATE = MFEMUL_SELECT1;
580 continue;
581 }
582
583 if ( (len == 5 && memcmp(receivedCmd, cmd1, len) == 0) ||
584 (len == 5 && memcmp(receivedCmd, cmd2, len) == 0) ) {
585 //WUPB && REQB
586 cardSTATE = MFEMUL_SELECT1;
587 } else if ( len == 7 && receivedCmd[0] == ISO14443B_HALT ) {
588 cardSTATE = MFEMUL_HALTED;
589 } else if ( len == sizeof(cmd4) && receivedCmd[0] == ISO14443B_ATTRIB ) {
590 cardSTATE = MFEMUL_SELECT2;
591 } else {
592 // SLOT MARKER command?!?
593 // ISO7816?!?
594 Dbprintf("new cmd from reader: len=%d, cmdsRecvd=%d", len, cmdsRecvd);
595
596 // CRC Check
597 uint8_t b1, b2;
598 if (len >= 3){ // if crc exists
599 ComputeCrc14443(CRC_14443_B, receivedCmd, len-2, &b1, &b2);
600 if(b1 != receivedCmd[len-2] || b2 != receivedCmd[len-1])
601 DbpString("+++CRC fail");
602 else
603 DbpString("CRC passes");
604 }
605 cardSTATE = MFEMUL_IDLE;
606 }
607
608 switch(cardSTATE){
609 case MFEMUL_NOFIELD:
610 case MFEMUL_HALTED:
611 case MFEMUL_IDLE:{
612 LogTrace(receivedCmd, len, 0, 0, NULL, TRUE);
613 break;
614 }
615 case MFEMUL_SELECT1:
616 TransmitFor14443b_AsTag( resp1Code, resp1CodeLen );
617 LogTrace(response1, sizeof(response1), 0, 0, NULL, FALSE);
618 cardSTATE = MFEMUL_WORK;
619 break;
620 case MFEMUL_SELECT2:
621 TransmitFor14443b_AsTag( resp2Code, resp2CodeLen );
622 LogTrace(response2, sizeof(response2), 0, 0, NULL, FALSE);
623 cardSTATE = MFEMUL_HALTED;
624 break;
625 case MFEMUL_WORK:
626 break;
627 }
628
629 ++cmdsRecvd;
630 if(cmdsRecvd > 1000) {
631 DbpString("14B Simulate, 1000 commands later...");
632 break;
633 }
634 }
635 if (MF_DBGLEVEL >= 1) Dbprintf("Emulator stopped. Tracing: %d trace length: %d ", tracing, BigBuf_get_traceLen());
636
637 switch_off(); //simulate
638 }
639
640 //=============================================================================
641 // An ISO 14443 Type B reader. We take layer two commands, code them
642 // appropriately, and then send them to the tag. We then listen for the
643 // tag's response, which we leave in the buffer to be demodulated on the
644 // PC side.
645 //=============================================================================
646
647 /*
648 * Handles reception of a bit from the tag
649 *
650 * This function is called 2 times per bit (every 4 subcarrier cycles).
651 * Subcarrier frequency fs is 848kHz, 1/fs = 1,18us, i.e. function is called every 4,72us
652 *
653 * LED handling:
654 * LED C -> ON once we have received the SOF and are expecting the rest.
655 * LED C -> OFF once we have received EOF or are unsynced
656 *
657 * Returns: true if we received a EOF
658 * false if we are still waiting for some more
659 *
660 */
661 #ifndef SUBCARRIER_DETECT_THRESHOLD
662 # define SUBCARRIER_DETECT_THRESHOLD 8
663 #endif
664
665 static RAMFUNC int Handle14443bTagSamplesDemod(int ci, int cq) {
666 int v=0;// , myI, myQ = 0;
667 // The soft decision on the bit uses an estimate of just the
668 // quadrant of the reference angle, not the exact angle.
669 #define MAKE_SOFT_DECISION() { \
670 if(Demod.sumI > 0) { \
671 v = ci; \
672 } else { \
673 v = -ci; \
674 } \
675 if(Demod.sumQ > 0) { \
676 v += cq; \
677 } else { \
678 v -= cq; \
679 } \
680 }
681
682 // Subcarrier amplitude v = sqrt(ci^2 + cq^2), approximated here by abs(ci) + abs(cq)
683 // Subcarrier amplitude v = sqrt(ci^2 + cq^2), approximated here by max(abs(ci),abs(cq)) + 1/2*min(abs(ci),abs(cq)))
684 #define CHECK_FOR_SUBCARRIER() { \
685 if(ci < 0) { \
686 if(cq < 0) { /* ci < 0, cq < 0 */ \
687 if (cq < ci) { \
688 v = -cq - (ci >> 1); \
689 } else { \
690 v = -ci - (cq >> 1); \
691 } \
692 } else { /* ci < 0, cq >= 0 */ \
693 if (cq < -ci) { \
694 v = -ci + (cq >> 1); \
695 } else { \
696 v = cq - (ci >> 1); \
697 } \
698 } \
699 } else { \
700 if(cq < 0) { /* ci >= 0, cq < 0 */ \
701 if (-cq < ci) { \
702 v = ci - (cq >> 1); \
703 } else { \
704 v = -cq + (ci >> 1); \
705 } \
706 } else { /* ci >= 0, cq >= 0 */ \
707 if (cq < ci) { \
708 v = ci + (cq >> 1); \
709 } else { \
710 v = cq + (ci >> 1); \
711 } \
712 } \
713 } \
714 }
715
716 //note: couldn't we just use MAX(ABS(ci),ABS(cq)) + (MIN(ABS(ci),ABS(cq))/2) from common.h - marshmellow
717 #define CHECK_FOR_SUBCARRIER_un() { \
718 myI = ABS(ci); \
719 myQ = ABS(cq); \
720 v = MAX(myI,myQ) + (MIN(myI,myQ) >> 1); \
721 }
722
723 switch(Demod.state) {
724 case DEMOD_UNSYNCD:
725
726 CHECK_FOR_SUBCARRIER();
727
728 // subcarrier detected
729 if(v > SUBCARRIER_DETECT_THRESHOLD) {
730 Demod.state = DEMOD_PHASE_REF_TRAINING;
731 Demod.sumI = ci;
732 Demod.sumQ = cq;
733 Demod.posCount = 1;
734 }
735 break;
736
737 case DEMOD_PHASE_REF_TRAINING:
738 if(Demod.posCount < 8) {
739
740 CHECK_FOR_SUBCARRIER();
741
742 if (v > SUBCARRIER_DETECT_THRESHOLD) {
743 // set the reference phase (will code a logic '1') by averaging over 32 1/fs.
744 // note: synchronization time > 80 1/fs
745 Demod.sumI += ci;
746 Demod.sumQ += cq;
747 ++Demod.posCount;
748 } else {
749 // subcarrier lost
750 Demod.state = DEMOD_UNSYNCD;
751 }
752 } else {
753 Demod.state = DEMOD_AWAITING_FALLING_EDGE_OF_SOF;
754 }
755 break;
756
757 case DEMOD_AWAITING_FALLING_EDGE_OF_SOF:
758
759 MAKE_SOFT_DECISION();
760
761 if(v < 0) { // logic '0' detected
762 Demod.state = DEMOD_GOT_FALLING_EDGE_OF_SOF;
763 Demod.posCount = 0; // start of SOF sequence
764 } else {
765 // maximum length of TR1 = 200 1/fs
766 if(Demod.posCount > 25*2) Demod.state = DEMOD_UNSYNCD;
767 }
768 ++Demod.posCount;
769 break;
770
771 case DEMOD_GOT_FALLING_EDGE_OF_SOF:
772 ++Demod.posCount;
773
774 MAKE_SOFT_DECISION();
775
776 if(v > 0) {
777 // low phase of SOF too short (< 9 etu). Note: spec is >= 10, but FPGA tends to "smear" edges
778 if(Demod.posCount < 9*2) {
779 Demod.state = DEMOD_UNSYNCD;
780 } else {
781 LED_C_ON(); // Got SOF
782 Demod.startTime = GetCountSspClk();
783 Demod.state = DEMOD_AWAITING_START_BIT;
784 Demod.posCount = 0;
785 Demod.len = 0;
786 }
787 } else {
788 // low phase of SOF too long (> 12 etu)
789 if (Demod.posCount > 12*2) {
790 Demod.state = DEMOD_UNSYNCD;
791 LED_C_OFF();
792 }
793 }
794 break;
795
796 case DEMOD_AWAITING_START_BIT:
797 ++Demod.posCount;
798
799 MAKE_SOFT_DECISION();
800
801 if (v > 0) {
802 if(Demod.posCount > 3*2) { // max 19us between characters = 16 1/fs, max 3 etu after low phase of SOF = 24 1/fs
803 Demod.state = DEMOD_UNSYNCD;
804 LED_C_OFF();
805 }
806 } else { // start bit detected
807 Demod.bitCount = 0;
808 Demod.posCount = 1; // this was the first half
809 Demod.thisBit = v;
810 Demod.shiftReg = 0;
811 Demod.state = DEMOD_RECEIVING_DATA;
812 }
813 break;
814
815 case DEMOD_RECEIVING_DATA:
816
817 MAKE_SOFT_DECISION();
818
819 if (Demod.posCount == 0) {
820 // first half of bit
821 Demod.thisBit = v;
822 Demod.posCount = 1;
823 } else {
824 // second half of bit
825 Demod.thisBit += v;
826 Demod.shiftReg >>= 1;
827
828 // logic '1'
829 if(Demod.thisBit > 0) Demod.shiftReg |= 0x200;
830
831 ++Demod.bitCount;
832
833 if(Demod.bitCount == 10) {
834
835 uint16_t s = Demod.shiftReg;
836
837 // stop bit == '1', start bit == '0'
838 if((s & 0x200) && !(s & 0x001)) {
839 uint8_t b = (s >> 1);
840 Demod.output[Demod.len] = b;
841 ++Demod.len;
842 Demod.state = DEMOD_AWAITING_START_BIT;
843 } else {
844 Demod.state = DEMOD_UNSYNCD;
845 Demod.endTime = GetCountSspClk();
846 LED_C_OFF();
847
848 // This is EOF (start, stop and all data bits == '0'
849 if(s == 0) return TRUE;
850 }
851 }
852 Demod.posCount = 0;
853 }
854 break;
855
856 default:
857 Demod.state = DEMOD_UNSYNCD;
858 LED_C_OFF();
859 break;
860 }
861 return FALSE;
862 }
863
864
865 /*
866 * Demodulate the samples we received from the tag, also log to tracebuffer
867 * quiet: set to 'TRUE' to disable debug output
868 */
869 static void GetTagSamplesFor14443bDemod() {
870 bool gotFrame = FALSE;
871 int lastRxCounter = ISO14443B_DMA_BUFFER_SIZE;
872 int max = 0, ci = 0, cq = 0, samples = 0;
873 uint32_t time_0 = 0, time_stop = 0;
874
875 BigBuf_free();
876
877 // Set up the demodulator for tag -> reader responses.
878 DemodInit(BigBuf_malloc(MAX_FRAME_SIZE));
879
880 // The DMA buffer, used to stream samples from the FPGA
881 int8_t *dmaBuf = (int8_t*) BigBuf_malloc(ISO14443B_DMA_BUFFER_SIZE);
882 int8_t *upTo = dmaBuf;
883
884 // Setup and start DMA.
885 if ( !FpgaSetupSscDma((uint8_t*) dmaBuf, ISO14443B_DMA_BUFFER_SIZE) ){
886 if (MF_DBGLEVEL > 1) Dbprintf("FpgaSetupSscDma failed. Exiting");
887 return;
888 }
889
890 time_0 = GetCountSspClk();
891
892 // And put the FPGA in the appropriate mode
893 FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ);
894
895 while( !BUTTON_PRESS() ) {
896 WDT_HIT();
897
898 int behindBy = lastRxCounter - AT91C_BASE_PDC_SSC->PDC_RCR;
899 if(behindBy > max) max = behindBy;
900
901 // rx counter - dma counter? (how much?) & (mod) dma buff / 2. (since 2bytes at the time is read)
902 while(((lastRxCounter - AT91C_BASE_PDC_SSC->PDC_RCR) & (ISO14443B_DMA_BUFFER_SIZE-1)) > 2) {
903
904 ci = upTo[0];
905 cq = upTo[1];
906 upTo += 2;
907 samples += 2;
908
909 // restart DMA buffer to receive again.
910 if(upTo >= dmaBuf + ISO14443B_DMA_BUFFER_SIZE) {
911 upTo = dmaBuf;
912 AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) upTo;
913 AT91C_BASE_PDC_SSC->PDC_RNCR = ISO14443B_DMA_BUFFER_SIZE;
914 }
915
916 lastRxCounter -= 2;
917 if(lastRxCounter <= 0)
918 lastRxCounter += ISO14443B_DMA_BUFFER_SIZE;
919
920 // is this | 0x01 the error? & 0xfe in https://github.com/Proxmark/proxmark3/issues/103
921 //gotFrame = Handle14443bTagSamplesDemod(ci & 0xfe, cq & 0xfe);
922 gotFrame = Handle14443bTagSamplesDemod(ci, cq);
923 if ( gotFrame ) break;
924 LED_A_INV();
925 }
926
927 time_stop = GetCountSspClk() - time_0;
928
929 if(time_stop > iso14b_timeout || gotFrame) break;
930 }
931
932 FpgaDisableSscDma();
933
934 if (MF_DBGLEVEL >= 3) {
935 Dbprintf("max behindby = %d, samples = %d, gotFrame = %s, Demod.state = %d, Demod.len = %u",
936 max,
937 samples,
938 (gotFrame) ? "true" : "false",
939 Demod.state,
940 Demod.len
941 );
942 }
943 if ( Demod.len > 0 )
944 LogTrace(Demod.output, Demod.len, Demod.startTime, Demod.endTime, NULL, FALSE);
945 }
946
947
948 //-----------------------------------------------------------------------------
949 // Transmit the command (to the tag) that was placed in ToSend[].
950 //-----------------------------------------------------------------------------
951 static void TransmitFor14443b_AsReader(void) {
952
953 FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_TX | FPGA_HF_READER_TX_SHALLOW_MOD);
954 SpinDelay(20);
955
956 int c;
957 // we could been in following mode:
958 // FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ
959 // if its second call or more
960
961 // What does this loop do? Is it TR1?
962 for(c = 0; c < 10;) {
963 if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
964 AT91C_BASE_SSC->SSC_THR = 0xFF;
965 ++c;
966 }
967 }
968
969 // Send frame loop
970 for(c = 0; c < ToSendMax;) {
971 if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
972 AT91C_BASE_SSC->SSC_THR = ToSend[c];
973 ++c;
974 }
975 }
976 WDT_HIT();
977 }
978
979 //-----------------------------------------------------------------------------
980 // Code a layer 2 command (string of octets, including CRC) into ToSend[],
981 // so that it is ready to transmit to the tag using TransmitFor14443b().
982 //-----------------------------------------------------------------------------
983 static void CodeIso14443bAsReader(const uint8_t *cmd, int len)
984 {
985 /*
986 * Reader data transmission:
987 * - no modulation ONES
988 * - SOF
989 * - Command, data and CRC_B
990 * - EOF
991 * - no modulation ONES
992 *
993 * 1 ETU == 1 BIT!
994 * TR0 - 8 ETUS minimum.
995 */
996 int i;
997 uint8_t b;
998
999 ToSendReset();
1000
1001 // Send SOF
1002 // 10-11 ETUs of ZERO
1003 for(i = 0; i < 10; ++i) ToSendStuffBit(0);
1004
1005 // 2-3 ETUs of ONE
1006 ToSendStuffBit(1);
1007 ToSendStuffBit(1);
1008 ToSendStuffBit(1);
1009
1010 // Sending cmd, LSB
1011 // from here we add BITS
1012 for(i = 0; i < len; ++i) {
1013 // Start bit
1014 ToSendStuffBit(0);
1015 // Data bits
1016 b = cmd[i];
1017 if ( b & 1 ) ToSendStuffBit(1); else ToSendStuffBit(0);
1018 if ( (b>>1) & 1) ToSendStuffBit(1); else ToSendStuffBit(0);
1019 if ( (b>>2) & 1) ToSendStuffBit(1); else ToSendStuffBit(0);
1020 if ( (b>>3) & 1) ToSendStuffBit(1); else ToSendStuffBit(0);
1021 if ( (b>>4) & 1) ToSendStuffBit(1); else ToSendStuffBit(0);
1022 if ( (b>>5) & 1) ToSendStuffBit(1); else ToSendStuffBit(0);
1023 if ( (b>>6) & 1) ToSendStuffBit(1); else ToSendStuffBit(0);
1024 if ( (b>>7) & 1) ToSendStuffBit(1); else ToSendStuffBit(0);
1025 // Stop bit
1026 ToSendStuffBit(1);
1027 // EGT extra guard time
1028 // For PCD it ranges 0-57us (1etu = 9us)
1029 ToSendStuffBit(1);
1030 ToSendStuffBit(1);
1031 ToSendStuffBit(1);
1032 }
1033
1034 // Send EOF
1035 // 10-11 ETUs of ZERO
1036 for(i = 0; i < 10; ++i) ToSendStuffBit(0);
1037
1038 // Transition time. TR0 - guard time
1039 // 8ETUS minum?
1040 // Per specification, Subcarrier must be stopped no later than 2 ETUs after EOF.
1041 for(i = 0; i < 40 ; ++i) ToSendStuffBit(1);
1042
1043 // TR1 - Synchronization time
1044 // Convert from last character reference to length
1045 ++ToSendMax;
1046 }
1047
1048
1049 /**
1050 Convenience function to encode, transmit and trace iso 14443b comms
1051 **/
1052 static void CodeAndTransmit14443bAsReader(const uint8_t *cmd, int len) {
1053
1054 CodeIso14443bAsReader(cmd, len);
1055
1056 uint32_t time_start = GetCountSspClk();
1057
1058 TransmitFor14443b_AsReader();
1059
1060 if(trigger) LED_A_ON();
1061
1062 LogTrace(cmd, len, time_start, GetCountSspClk()-time_start, NULL, TRUE);
1063 }
1064
1065 /* Sends an APDU to the tag
1066 * TODO: check CRC and preamble
1067 */
1068 uint8_t iso14443b_apdu(uint8_t const *message, size_t message_length, uint8_t *response)
1069 {
1070 uint8_t crc[2] = {0x00, 0x00};
1071 uint8_t message_frame[message_length + 4];
1072 // PCB
1073 message_frame[0] = 0x0A | pcb_blocknum;
1074 pcb_blocknum ^= 1;
1075 // CID
1076 message_frame[1] = 0;
1077 // INF
1078 memcpy(message_frame + 2, message, message_length);
1079 // EDC (CRC)
1080 ComputeCrc14443(CRC_14443_B, message_frame, message_length + 2, &message_frame[message_length + 2], &message_frame[message_length + 3]);
1081 // send
1082 CodeAndTransmit14443bAsReader(message_frame, message_length + 4); //no
1083 // get response
1084 GetTagSamplesFor14443bDemod(); //no
1085 if(Demod.len < 3)
1086 return 0;
1087
1088 // VALIDATE CRC
1089 ComputeCrc14443(CRC_14443_B, Demod.output, Demod.len-2, &crc[0], &crc[1]);
1090 if ( crc[0] != Demod.output[Demod.len-2] || crc[1] != Demod.output[Demod.len-1] )
1091 return 0;
1092
1093 // copy response contents
1094 if(response != NULL)
1095 memcpy(response, Demod.output, Demod.len);
1096
1097 return Demod.len;
1098 }
1099
1100 /**
1101 * SRx Initialise.
1102 */
1103 uint8_t iso14443b_select_srx_card(iso14b_card_select_t *card )
1104 {
1105 // INITIATE command: wake up the tag using the INITIATE
1106 static const uint8_t init_srx[] = { ISO14443B_INITIATE, 0x00, 0x97, 0x5b };
1107 // SELECT command (with space for CRC)
1108 uint8_t select_srx[] = { ISO14443B_SELECT, 0x00, 0x00, 0x00};
1109 // temp to calc crc.
1110 uint8_t crc[2] = {0x00, 0x00};
1111
1112 CodeAndTransmit14443bAsReader(init_srx, sizeof(init_srx));
1113 GetTagSamplesFor14443bDemod(); //no
1114
1115 if (Demod.len == 0) return 2;
1116
1117 // Randomly generated Chip ID
1118 if (card) card->chipid = Demod.output[0];
1119
1120 select_srx[1] = Demod.output[0];
1121
1122 ComputeCrc14443(CRC_14443_B, select_srx, 2, &select_srx[2], &select_srx[3]);
1123 CodeAndTransmit14443bAsReader(select_srx, sizeof(select_srx));
1124 GetTagSamplesFor14443bDemod(); //no
1125
1126 if (Demod.len != 3) return 2;
1127
1128 // Check the CRC of the answer:
1129 ComputeCrc14443(CRC_14443_B, Demod.output, Demod.len-2 , &crc[0], &crc[1]);
1130 if(crc[0] != Demod.output[1] || crc[1] != Demod.output[2]) return 3;
1131
1132 // Check response from the tag: should be the same UID as the command we just sent:
1133 if (select_srx[1] != Demod.output[0]) return 1;
1134
1135 // First get the tag's UID:
1136 select_srx[0] = ISO14443B_GET_UID;
1137
1138 ComputeCrc14443(CRC_14443_B, select_srx, 1 , &select_srx[1], &select_srx[2]);
1139 CodeAndTransmit14443bAsReader(select_srx, 3); // Only first three bytes for this one
1140 GetTagSamplesFor14443bDemod(); //no
1141
1142 if (Demod.len != 10) return 2;
1143
1144 // The check the CRC of the answer
1145 ComputeCrc14443(CRC_14443_B, Demod.output, Demod.len-2, &crc[0], &crc[1]);
1146 if(crc[0] != Demod.output[8] || crc[1] != Demod.output[9]) return 3;
1147
1148 if (card) {
1149 card->uidlen = 8;
1150 memcpy(card->uid, Demod.output, 8);
1151 }
1152
1153 return 0;
1154 }
1155 /* Perform the ISO 14443 B Card Selection procedure
1156 * Currently does NOT do any collision handling.
1157 * It expects 0-1 cards in the device's range.
1158 * TODO: Support multiple cards (perform anticollision)
1159 * TODO: Verify CRC checksums
1160 */
1161 uint8_t iso14443b_select_card(iso14b_card_select_t *card )
1162 {
1163 // WUPB command (including CRC)
1164 // Note: WUPB wakes up all tags, REQB doesn't wake up tags in HALT state
1165 static const uint8_t wupb[] = { ISO14443B_REQB, 0x00, 0x08, 0x39, 0x73 };
1166 // ATTRIB command (with space for CRC)
1167 uint8_t attrib[] = { ISO14443B_ATTRIB, 0x00, 0x00, 0x00, 0x00, 0x00, 0x08, 0x00, 0x00, 0x00, 0x00};
1168
1169 // temp to calc crc.
1170 uint8_t crc[2] = {0x00, 0x00};
1171
1172 // first, wake up the tag
1173 CodeAndTransmit14443bAsReader(wupb, sizeof(wupb));
1174 GetTagSamplesFor14443bDemod(); //select_card
1175
1176 // ATQB too short?
1177 if (Demod.len < 14) return 2;
1178
1179 // VALIDATE CRC
1180 ComputeCrc14443(CRC_14443_B, Demod.output, Demod.len-2, &crc[0], &crc[1]);
1181 if ( crc[0] != Demod.output[12] || crc[1] != Demod.output[13] )
1182 return 3;
1183
1184 if (card) {
1185 card->uidlen = 4;
1186 memcpy(card->uid, Demod.output+1, 4);
1187 memcpy(card->atqb, Demod.output+5, 7);
1188 }
1189
1190 // copy the PUPI to ATTRIB ( PUPI == UID )
1191 memcpy(attrib + 1, Demod.output + 1, 4);
1192
1193 // copy the protocol info from ATQB (Protocol Info -> Protocol_Type) into ATTRIB (Param 3)
1194 attrib[7] = Demod.output[10] & 0x0F;
1195 ComputeCrc14443(CRC_14443_B, attrib, 9, attrib + 9, attrib + 10);
1196
1197 CodeAndTransmit14443bAsReader(attrib, sizeof(attrib));
1198 GetTagSamplesFor14443bDemod();//select_card
1199
1200 // Answer to ATTRIB too short?
1201 if(Demod.len < 3) return 2;
1202
1203 // VALIDATE CRC
1204 ComputeCrc14443(CRC_14443_B, Demod.output, Demod.len-2, &crc[0], &crc[1]);
1205 if ( crc[0] != Demod.output[1] || crc[1] != Demod.output[2] )
1206 return 3;
1207
1208 // CID
1209 if (card) card->cid = Demod.output[0];
1210
1211 uint8_t fwt = card->atqb[6]>>4;
1212 if ( fwt < 16 ){
1213 uint32_t fwt_time = (302 << fwt);
1214 iso14b_set_timeout( fwt_time);
1215 }
1216 // reset PCB block number
1217 pcb_blocknum = 0;
1218 return 0;
1219 }
1220
1221 // Set up ISO 14443 Type B communication (similar to iso14443a_setup)
1222 // field is setup for "Sending as Reader"
1223 void iso14443b_setup() {
1224 if (MF_DBGLEVEL > 3) Dbprintf("iso1443b_setup Enter");
1225 LEDsoff();
1226 FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
1227 //BigBuf_free();
1228 //BigBuf_Clear_ext(false);
1229
1230 // Initialize Demod and Uart structs
1231 DemodInit(BigBuf_malloc(MAX_FRAME_SIZE));
1232 UartInit(BigBuf_malloc(MAX_FRAME_SIZE));
1233
1234 // connect Demodulated Signal to ADC:
1235 SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
1236
1237 // Set up the synchronous serial port
1238 FpgaSetupSsc();
1239
1240 // Signal field is on with the appropriate LED
1241 FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_TX | FPGA_HF_READER_TX_SHALLOW_MOD);
1242 SpinDelay(100);
1243
1244 // Start the timer
1245 StartCountSspClk();
1246
1247 LED_D_ON();
1248 if (MF_DBGLEVEL > 3) Dbprintf("iso1443b_setup Exit");
1249 }
1250
1251 //-----------------------------------------------------------------------------
1252 // Read a SRI512 ISO 14443B tag.
1253 //
1254 // SRI512 tags are just simple memory tags, here we're looking at making a dump
1255 // of the contents of the memory. No anticollision algorithm is done, we assume
1256 // we have a single tag in the field.
1257 //
1258 // I tried to be systematic and check every answer of the tag, every CRC, etc...
1259 //-----------------------------------------------------------------------------
1260 void ReadSTMemoryIso14443b(uint8_t numofblocks)
1261 {
1262 FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
1263
1264 // Make sure that we start from off, since the tags are stateful;
1265 // confusing things will happen if we don't reset them between reads.
1266 switch_off(); // before ReadStMemory
1267
1268 set_tracing(TRUE);
1269
1270 uint8_t i = 0x00;
1271
1272 SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
1273 FpgaSetupSsc();
1274
1275 // Now give it time to spin up.
1276 // Signal field is on with the appropriate LED
1277 LED_D_ON();
1278 FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ);
1279 SpinDelay(20);
1280
1281 // First command: wake up the tag using the INITIATE command
1282 uint8_t cmd1[] = {ISO14443B_INITIATE, 0x00, 0x97, 0x5b};
1283 CodeAndTransmit14443bAsReader(cmd1, sizeof(cmd1)); //no
1284 GetTagSamplesFor14443bDemod(); // no
1285
1286 if (Demod.len == 0) {
1287 DbpString("No response from tag");
1288 set_tracing(FALSE);
1289 return;
1290 } else {
1291 Dbprintf("Randomly generated Chip ID (+ 2 byte CRC): %02x %02x %02x",
1292 Demod.output[0], Demod.output[1], Demod.output[2]);
1293 }
1294
1295 // There is a response, SELECT the uid
1296 DbpString("Now SELECT tag:");
1297 cmd1[0] = ISO14443B_SELECT; // 0x0E is SELECT
1298 cmd1[1] = Demod.output[0];
1299 ComputeCrc14443(CRC_14443_B, cmd1, 2, &cmd1[2], &cmd1[3]);
1300 CodeAndTransmit14443bAsReader(cmd1, sizeof(cmd1)); //no
1301 GetTagSamplesFor14443bDemod(); //no
1302 if (Demod.len != 3) {
1303 Dbprintf("Expected 3 bytes from tag, got %d", Demod.len);
1304 set_tracing(FALSE);
1305 return;
1306 }
1307 // Check the CRC of the answer:
1308 ComputeCrc14443(CRC_14443_B, Demod.output, 1 , &cmd1[2], &cmd1[3]);
1309 if(cmd1[2] != Demod.output[1] || cmd1[3] != Demod.output[2]) {
1310 DbpString("CRC Error reading select response.");
1311 set_tracing(FALSE);
1312 return;
1313 }
1314 // Check response from the tag: should be the same UID as the command we just sent:
1315 if (cmd1[1] != Demod.output[0]) {
1316 Dbprintf("Bad response to SELECT from Tag, aborting: %02x %02x", cmd1[1], Demod.output[0]);
1317 set_tracing(FALSE);
1318 return;
1319 }
1320
1321 // Tag is now selected,
1322 // First get the tag's UID:
1323 cmd1[0] = ISO14443B_GET_UID;
1324 ComputeCrc14443(CRC_14443_B, cmd1, 1 , &cmd1[1], &cmd1[2]);
1325 CodeAndTransmit14443bAsReader(cmd1, 3); // no -- Only first three bytes for this one
1326 GetTagSamplesFor14443bDemod(); //no
1327 if (Demod.len != 10) {
1328 Dbprintf("Expected 10 bytes from tag, got %d", Demod.len);
1329 set_tracing(FALSE);
1330 return;
1331 }
1332 // The check the CRC of the answer (use cmd1 as temporary variable):
1333 ComputeCrc14443(CRC_14443_B, Demod.output, 8, &cmd1[2], &cmd1[3]);
1334 if(cmd1[2] != Demod.output[8] || cmd1[3] != Demod.output[9]) {
1335 Dbprintf("CRC Error reading block! Expected: %04x got: %04x",
1336 (cmd1[2]<<8)+cmd1[3], (Demod.output[8]<<8)+Demod.output[9]);
1337 // Do not return;, let's go on... (we should retry, maybe ?)
1338 }
1339 Dbprintf("Tag UID (64 bits): %08x %08x",
1340 (Demod.output[7]<<24) + (Demod.output[6]<<16) + (Demod.output[5]<<8) + Demod.output[4],
1341 (Demod.output[3]<<24) + (Demod.output[2]<<16) + (Demod.output[1]<<8) + Demod.output[0]);
1342
1343 // Now loop to read all 16 blocks, address from 0 to last block
1344 Dbprintf("Tag memory dump, block 0 to %d", numofblocks);
1345 cmd1[0] = 0x08;
1346 i = 0x00;
1347 ++numofblocks;
1348
1349 for (;;) {
1350 if (i == numofblocks) {
1351 DbpString("System area block (0xff):");
1352 i = 0xff;
1353 }
1354 cmd1[1] = i;
1355 ComputeCrc14443(CRC_14443_B, cmd1, 2, &cmd1[2], &cmd1[3]);
1356 CodeAndTransmit14443bAsReader(cmd1, sizeof(cmd1)); //no
1357 GetTagSamplesFor14443bDemod(); //no
1358
1359 if (Demod.len != 6) { // Check if we got an answer from the tag
1360 DbpString("Expected 6 bytes from tag, got less...");
1361 return;
1362 }
1363 // The check the CRC of the answer (use cmd1 as temporary variable):
1364 ComputeCrc14443(CRC_14443_B, Demod.output, 4, &cmd1[2], &cmd1[3]);
1365 if(cmd1[2] != Demod.output[4] || cmd1[3] != Demod.output[5]) {
1366 Dbprintf("CRC Error reading block! Expected: %04x got: %04x",
1367 (cmd1[2]<<8)+cmd1[3], (Demod.output[4]<<8)+Demod.output[5]);
1368 // Do not return;, let's go on... (we should retry, maybe ?)
1369 }
1370 // Now print out the memory location:
1371 Dbprintf("Address=%02x, Contents=%08x, CRC=%04x", i,
1372 (Demod.output[3]<<24) + (Demod.output[2]<<16) + (Demod.output[1]<<8) + Demod.output[0],
1373 (Demod.output[4]<<8)+Demod.output[5]);
1374
1375 if (i == 0xff) break;
1376 ++i;
1377 }
1378
1379 set_tracing(FALSE);
1380 }
1381
1382
1383 static void iso1444b_setup_snoop(void){
1384 if (MF_DBGLEVEL > 3) Dbprintf("iso1443b_setup_snoop Enter");
1385 LEDsoff();
1386 FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
1387 BigBuf_free();
1388 BigBuf_Clear_ext(false);
1389 clear_trace();//setup snoop
1390 set_tracing(TRUE);
1391
1392 // Initialize Demod and Uart structs
1393 DemodInit(BigBuf_malloc(MAX_FRAME_SIZE));
1394 UartInit(BigBuf_malloc(MAX_FRAME_SIZE));
1395
1396 if (MF_DBGLEVEL > 1) {
1397 // Print debug information about the buffer sizes
1398 Dbprintf("Snooping buffers initialized:");
1399 Dbprintf(" Trace: %i bytes", BigBuf_max_traceLen());
1400 Dbprintf(" Reader -> tag: %i bytes", MAX_FRAME_SIZE);
1401 Dbprintf(" tag -> Reader: %i bytes", MAX_FRAME_SIZE);
1402 Dbprintf(" DMA: %i bytes", ISO14443B_DMA_BUFFER_SIZE);
1403 }
1404
1405 // connect Demodulated Signal to ADC:
1406 SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
1407
1408 // Setup for the DMA.
1409 FpgaSetupSsc();
1410
1411 // Set FPGA in the appropriate mode
1412 FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ | FPGA_HF_READER_RX_XCORR_SNOOP);
1413 SpinDelay(20);
1414
1415 // Start the SSP timer
1416 StartCountSspClk();
1417 if (MF_DBGLEVEL > 3) Dbprintf("iso1443b_setup_snoop Exit");
1418 }
1419
1420 //=============================================================================
1421 // Finally, the `sniffer' combines elements from both the reader and
1422 // simulated tag, to show both sides of the conversation.
1423 //=============================================================================
1424
1425 //-----------------------------------------------------------------------------
1426 // Record the sequence of commands sent by the reader to the tag, with
1427 // triggering so that we start recording at the point that the tag is moved
1428 // near the reader.
1429 //-----------------------------------------------------------------------------
1430 /*
1431 * Memory usage for this function, (within BigBuf)
1432 * Last Received command (reader->tag) - MAX_FRAME_SIZE
1433 * Last Received command (tag->reader) - MAX_FRAME_SIZE
1434 * DMA Buffer - ISO14443B_DMA_BUFFER_SIZE
1435 * Demodulated samples received - all the rest
1436 */
1437 void RAMFUNC SnoopIso14443b(void) {
1438
1439 uint32_t time_0 = 0, time_start = 0, time_stop = 0;
1440
1441 // We won't start recording the frames that we acquire until we trigger;
1442 // a good trigger condition to get started is probably when we see a
1443 // response from the tag.
1444 int triggered = TRUE; // TODO: set and evaluate trigger condition
1445 int ci, cq;
1446 int maxBehindBy = 0;
1447 //int behindBy = 0;
1448 int lastRxCounter = ISO14443B_DMA_BUFFER_SIZE;
1449
1450 bool TagIsActive = FALSE;
1451 bool ReaderIsActive = FALSE;
1452
1453 iso1444b_setup_snoop();
1454
1455 // The DMA buffer, used to stream samples from the FPGA
1456 int8_t *dmaBuf = (int8_t*) BigBuf_malloc(ISO14443B_DMA_BUFFER_SIZE);
1457 int8_t *upTo = dmaBuf;
1458
1459 // Setup and start DMA.
1460 if ( !FpgaSetupSscDma((uint8_t*) dmaBuf, ISO14443B_DMA_BUFFER_SIZE) ){
1461 if (MF_DBGLEVEL > 1) Dbprintf("FpgaSetupSscDma failed. Exiting");
1462 BigBuf_free();
1463 return;
1464 }
1465
1466 time_0 = GetCountSspClk();
1467
1468 // And now we loop, receiving samples.
1469 for(;;) {
1470
1471 WDT_HIT();
1472
1473 int behindBy = (lastRxCounter - AT91C_BASE_PDC_SSC->PDC_RCR) & (ISO14443B_DMA_BUFFER_SIZE-1);
1474
1475 if ( behindBy > maxBehindBy )
1476 maxBehindBy = behindBy;
1477
1478 if ( behindBy < 2 ) continue;
1479
1480 ci = upTo[0];
1481 cq = upTo[1];
1482 upTo += 2;
1483
1484 lastRxCounter -= 2;
1485
1486 if (upTo >= dmaBuf + ISO14443B_DMA_BUFFER_SIZE) {
1487 upTo = dmaBuf;
1488 lastRxCounter += ISO14443B_DMA_BUFFER_SIZE;
1489 AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) dmaBuf;
1490 AT91C_BASE_PDC_SSC->PDC_RNCR = ISO14443B_DMA_BUFFER_SIZE;
1491 WDT_HIT();
1492
1493 // TODO: understand whether we can increase/decrease as we want or not?
1494 if ( behindBy > ( 9 * ISO14443B_DMA_BUFFER_SIZE/10) ) {
1495 Dbprintf("blew circular buffer! behindBy=%d", behindBy);
1496 break;
1497 }
1498
1499 if(!tracing) {
1500 DbpString("Trace full");
1501 break;
1502 }
1503
1504 if(BUTTON_PRESS()) {
1505 DbpString("cancelled");
1506 break;
1507 }
1508 }
1509
1510 if (!TagIsActive) {
1511
1512 LED_A_ON();
1513
1514 // no need to try decoding reader data if the tag is sending
1515 if (Handle14443bReaderUartBit(ci & 0x01)) {
1516
1517 time_stop = (GetCountSspClk()-time_0);
1518
1519 if (triggered)
1520 LogTrace(Uart.output, Uart.byteCnt, time_start, time_stop, NULL, TRUE);
1521
1522 /* And ready to receive another command. */
1523 UartReset();
1524 /* And also reset the demod code, which might have been */
1525 /* false-triggered by the commands from the reader. */
1526 DemodReset();
1527 } else {
1528 time_start = (GetCountSspClk()-time_0);
1529 }
1530
1531 if (Handle14443bReaderUartBit(cq & 0x01)) {
1532
1533 time_stop = (GetCountSspClk()-time_0);
1534
1535 if (triggered)
1536 LogTrace(Uart.output, Uart.byteCnt, time_start, time_stop, NULL, TRUE);
1537
1538 /* And ready to receive another command. */
1539 UartReset();
1540 /* And also reset the demod code, which might have been */
1541 /* false-triggered by the commands from the reader. */
1542 DemodReset();
1543 } else {
1544 time_start = (GetCountSspClk()-time_0);
1545 }
1546 ReaderIsActive = (Uart.state > STATE_GOT_FALLING_EDGE_OF_SOF);
1547 LED_A_OFF();
1548 }
1549
1550 if(!ReaderIsActive) {
1551 // no need to try decoding tag data if the reader is sending - and we cannot afford the time
1552 // is this | 0x01 the error? & 0xfe in https://github.com/Proxmark/proxmark3/issues/103
1553 if(Handle14443bTagSamplesDemod(ci & 0xFE, cq & 0xFE)) {
1554
1555 time_stop = (GetCountSspClk()-time_0);
1556
1557 LogTrace(Demod.output, Demod.len, time_start, time_stop, NULL, FALSE);
1558
1559 triggered = TRUE;
1560
1561 // And ready to receive another response.
1562 DemodReset();
1563 } else {
1564 time_start = (GetCountSspClk()-time_0);
1565 }
1566 TagIsActive = (Demod.state > DEMOD_GOT_FALLING_EDGE_OF_SOF);
1567 }
1568 }
1569
1570 switch_off(); // Snoop
1571
1572 DbpString("Snoop statistics:");
1573 Dbprintf(" Max behind by: %i", maxBehindBy);
1574 Dbprintf(" Uart State: %x ByteCount: %i ByteCountMax: %i", Uart.state, Uart.byteCnt, Uart.byteCntMax);
1575 Dbprintf(" Trace length: %i", BigBuf_get_traceLen());
1576
1577 // free mem refs.
1578 if ( dmaBuf ) dmaBuf = NULL;
1579 if ( upTo ) upTo = NULL;
1580 // Uart.byteCntMax should be set with ATQB value..
1581 }
1582
1583 void iso14b_set_trigger(bool enable) {
1584 trigger = enable;
1585 }
1586
1587 /*
1588 * Send raw command to tag ISO14443B
1589 * @Input
1590 * param flags enum ISO14B_COMMAND. (mifare.h)
1591 * len len of buffer data
1592 * data buffer with bytes to send
1593 *
1594 * @Output
1595 * none
1596 *
1597 */
1598 void SendRawCommand14443B_Ex(UsbCommand *c)
1599 {
1600 iso14b_command_t param = c->arg[0];
1601 size_t len = c->arg[1] & 0xffff;
1602 uint8_t *cmd = c->d.asBytes;
1603 uint8_t status = 0;
1604 uint32_t sendlen = sizeof(iso14b_card_select_t);
1605 uint8_t buf[USB_CMD_DATA_SIZE] = {0x00};
1606
1607 if (MF_DBGLEVEL > 3) Dbprintf("14b raw: param, %04x", param );
1608
1609 // turn on trigger (LED_A)
1610 if ((param & ISO14B_REQUEST_TRIGGER) == ISO14B_REQUEST_TRIGGER)
1611 iso14b_set_trigger(TRUE);
1612
1613 if ((param & ISO14B_CONNECT) == ISO14B_CONNECT) {
1614 // Make sure that we start from off, since the tags are stateful;
1615 // confusing things will happen if we don't reset them between reads.
1616 //switch_off(); // before connect in raw
1617 iso14443b_setup();
1618 }
1619
1620 set_tracing(TRUE);
1621
1622 if ((param & ISO14B_SELECT_STD) == ISO14B_SELECT_STD) {
1623 iso14b_card_select_t *card = (iso14b_card_select_t*)buf;
1624 status = iso14443b_select_card(card);
1625 cmd_send(CMD_ACK, status, sendlen, 0, buf, sendlen);
1626 // 0: OK 2: attrib fail, 3:crc fail,
1627 if ( status > 0 ) return;
1628 }
1629
1630 if ((param & ISO14B_SELECT_SR) == ISO14B_SELECT_SR) {
1631 iso14b_card_select_t *card = (iso14b_card_select_t*)buf;
1632 status = iso14443b_select_srx_card(card);
1633 cmd_send(CMD_ACK, status, sendlen, 0, buf, sendlen);
1634 // 0: OK 2: attrib fail, 3:crc fail,
1635 if ( status > 0 ) return;
1636 }
1637
1638 if ((param & ISO14B_APDU) == ISO14B_APDU) {
1639 status = iso14443b_apdu(cmd, len, buf);
1640 cmd_send(CMD_ACK, status, status, 0, buf, status);
1641 }
1642
1643 if ((param & ISO14B_RAW) == ISO14B_RAW) {
1644 if((param & ISO14B_APPEND_CRC) == ISO14B_APPEND_CRC) {
1645 AppendCrc14443b(cmd, len);
1646 len += 2;
1647 }
1648
1649 CodeAndTransmit14443bAsReader(cmd, len); // raw
1650 GetTagSamplesFor14443bDemod(); // raw
1651
1652 sendlen = MIN(Demod.len, USB_CMD_DATA_SIZE);
1653 status = (Demod.len > 0) ? 0 : 1;
1654 cmd_send(CMD_ACK, status, sendlen, 0, Demod.output, sendlen);
1655 }
1656
1657 // turn off trigger (LED_A)
1658 if ((param & ISO14B_REQUEST_TRIGGER) == ISO14B_REQUEST_TRIGGER)
1659 iso14b_set_trigger(FALSE);
1660
1661 // turn off antenna et al
1662 // we don't send a HALT command.
1663 if ((param & ISO14B_DISCONNECT) == ISO14B_DISCONNECT) {
1664 if (MF_DBGLEVEL > 3) Dbprintf("disconnect");
1665 switch_off(); // disconnect raw
1666 } else {
1667 //FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_TX | FPGA_HF_READER_TX_SHALLOW_MOD);
1668 }
1669
1670 }
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