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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 14443. This includes both the reader software and
9 // the `fake tag' modes. At the moment only the Type B modulation is
10 // supported.
11 //-----------------------------------------------------------------------------
12
13 #include "proxmark3.h"
14 #include "apps.h"
15 #include "util.h"
16 #include "string.h"
17
18 #include "iso14443crc.h"
19
20 //static void GetSamplesFor14443(int weTx, int n);
21
22 #define DEMOD_TRACE_SIZE 4096
23 #define READER_TAG_BUFFER_SIZE 2048
24 #define TAG_READER_BUFFER_SIZE 2048
25 #define DEMOD_DMA_BUFFER_SIZE 1024
26
27 //=============================================================================
28 // An ISO 14443 Type B tag. We listen for commands from the reader, using
29 // a UART kind of thing that's implemented in software. When we get a
30 // frame (i.e., a group of bytes between SOF and EOF), we check the CRC.
31 // If it's good, then we can do something appropriate with it, and send
32 // a response.
33 //=============================================================================
34
35 //-----------------------------------------------------------------------------
36 // Code up a string of octets at layer 2 (including CRC, we don't generate
37 // that here) so that they can be transmitted to the reader. Doesn't transmit
38 // them yet, just leaves them ready to send in ToSend[].
39 //-----------------------------------------------------------------------------
40 static void CodeIso14443bAsTag(const uint8_t *cmd, int len)
41 {
42 int i;
43
44 ToSendReset();
45
46 // Transmit a burst of ones, as the initial thing that lets the
47 // reader get phase sync. This (TR1) must be > 80/fs, per spec,
48 // but tag that I've tried (a Paypass) exceeds that by a fair bit,
49 // so I will too.
50 for(i = 0; i < 20; i++) {
51 ToSendStuffBit(1);
52 ToSendStuffBit(1);
53 ToSendStuffBit(1);
54 ToSendStuffBit(1);
55 }
56
57 // Send SOF.
58 for(i = 0; i < 10; i++) {
59 ToSendStuffBit(0);
60 ToSendStuffBit(0);
61 ToSendStuffBit(0);
62 ToSendStuffBit(0);
63 }
64 for(i = 0; i < 2; i++) {
65 ToSendStuffBit(1);
66 ToSendStuffBit(1);
67 ToSendStuffBit(1);
68 ToSendStuffBit(1);
69 }
70
71 for(i = 0; i < len; i++) {
72 int j;
73 uint8_t b = cmd[i];
74
75 // Start bit
76 ToSendStuffBit(0);
77 ToSendStuffBit(0);
78 ToSendStuffBit(0);
79 ToSendStuffBit(0);
80
81 // Data bits
82 for(j = 0; j < 8; j++) {
83 if(b & 1) {
84 ToSendStuffBit(1);
85 ToSendStuffBit(1);
86 ToSendStuffBit(1);
87 ToSendStuffBit(1);
88 } else {
89 ToSendStuffBit(0);
90 ToSendStuffBit(0);
91 ToSendStuffBit(0);
92 ToSendStuffBit(0);
93 }
94 b >>= 1;
95 }
96
97 // Stop bit
98 ToSendStuffBit(1);
99 ToSendStuffBit(1);
100 ToSendStuffBit(1);
101 ToSendStuffBit(1);
102 }
103
104 // Send SOF.
105 for(i = 0; i < 10; i++) {
106 ToSendStuffBit(0);
107 ToSendStuffBit(0);
108 ToSendStuffBit(0);
109 ToSendStuffBit(0);
110 }
111 for(i = 0; i < 10; i++) {
112 ToSendStuffBit(1);
113 ToSendStuffBit(1);
114 ToSendStuffBit(1);
115 ToSendStuffBit(1);
116 }
117
118 // Convert from last byte pos to length
119 ToSendMax++;
120
121 // Add a few more for slop
122 ToSendMax += 2;
123 }
124
125 //-----------------------------------------------------------------------------
126 // The software UART that receives commands from the reader, and its state
127 // variables.
128 //-----------------------------------------------------------------------------
129 static struct {
130 enum {
131 STATE_UNSYNCD,
132 STATE_GOT_FALLING_EDGE_OF_SOF,
133 STATE_AWAITING_START_BIT,
134 STATE_RECEIVING_DATA,
135 STATE_ERROR_WAIT
136 } state;
137 uint16_t shiftReg;
138 int bitCnt;
139 int byteCnt;
140 int byteCntMax;
141 int posCnt;
142 uint8_t *output;
143 } Uart;
144
145 /* Receive & handle a bit coming from the reader.
146 *
147 * LED handling:
148 * LED A -> ON once we have received the SOF and are expecting the rest.
149 * LED A -> OFF once we have received EOF or are in error state or unsynced
150 *
151 * Returns: true if we received a EOF
152 * false if we are still waiting for some more
153 */
154 static int Handle14443UartBit(int bit)
155 {
156 switch(Uart.state) {
157 case STATE_UNSYNCD:
158 LED_A_OFF();
159 if(!bit) {
160 // we went low, so this could be the beginning
161 // of an SOF
162 Uart.state = STATE_GOT_FALLING_EDGE_OF_SOF;
163 Uart.posCnt = 0;
164 Uart.bitCnt = 0;
165 }
166 break;
167
168 case STATE_GOT_FALLING_EDGE_OF_SOF:
169 Uart.posCnt++;
170 if(Uart.posCnt == 2) {
171 if(bit) {
172 if(Uart.bitCnt >= 10) {
173 // we've seen enough consecutive
174 // zeros that it's a valid SOF
175 Uart.posCnt = 0;
176 Uart.byteCnt = 0;
177 Uart.state = STATE_AWAITING_START_BIT;
178 LED_A_ON(); // Indicate we got a valid SOF
179 } else {
180 // didn't stay down long enough
181 // before going high, error
182 Uart.state = STATE_ERROR_WAIT;
183 }
184 } else {
185 // do nothing, keep waiting
186 }
187 Uart.bitCnt++;
188 }
189 if(Uart.posCnt >= 4) Uart.posCnt = 0;
190 if(Uart.bitCnt > 14) {
191 // Give up if we see too many zeros without
192 // a one, too.
193 Uart.state = STATE_ERROR_WAIT;
194 }
195 break;
196
197 case STATE_AWAITING_START_BIT:
198 Uart.posCnt++;
199 if(bit) {
200 if(Uart.posCnt > 25) {
201 // stayed high for too long between
202 // characters, error
203 Uart.state = STATE_ERROR_WAIT;
204 }
205 } else {
206 // falling edge, this starts the data byte
207 Uart.posCnt = 0;
208 Uart.bitCnt = 0;
209 Uart.shiftReg = 0;
210 Uart.state = STATE_RECEIVING_DATA;
211 LED_A_ON(); // Indicate we're receiving
212 }
213 break;
214
215 case STATE_RECEIVING_DATA:
216 Uart.posCnt++;
217 if(Uart.posCnt == 2) {
218 // time to sample a bit
219 Uart.shiftReg >>= 1;
220 if(bit) {
221 Uart.shiftReg |= 0x200;
222 }
223 Uart.bitCnt++;
224 }
225 if(Uart.posCnt >= 4) {
226 Uart.posCnt = 0;
227 }
228 if(Uart.bitCnt == 10) {
229 if((Uart.shiftReg & 0x200) && !(Uart.shiftReg & 0x001))
230 {
231 // this is a data byte, with correct
232 // start and stop bits
233 Uart.output[Uart.byteCnt] = (Uart.shiftReg >> 1) & 0xff;
234 Uart.byteCnt++;
235
236 if(Uart.byteCnt >= Uart.byteCntMax) {
237 // Buffer overflowed, give up
238 Uart.posCnt = 0;
239 Uart.state = STATE_ERROR_WAIT;
240 } else {
241 // so get the next byte now
242 Uart.posCnt = 0;
243 Uart.state = STATE_AWAITING_START_BIT;
244 }
245 } else if(Uart.shiftReg == 0x000) {
246 // this is an EOF byte
247 LED_A_OFF(); // Finished receiving
248 return TRUE;
249 } else {
250 // this is an error
251 Uart.posCnt = 0;
252 Uart.state = STATE_ERROR_WAIT;
253 }
254 }
255 break;
256
257 case STATE_ERROR_WAIT:
258 // We're all screwed up, so wait a little while
259 // for whatever went wrong to finish, and then
260 // start over.
261 Uart.posCnt++;
262 if(Uart.posCnt > 10) {
263 Uart.state = STATE_UNSYNCD;
264 }
265 break;
266
267 default:
268 Uart.state = STATE_UNSYNCD;
269 break;
270 }
271
272 // This row make the error blew circular buffer in hf 14b snoop
273 //if (Uart.state == STATE_ERROR_WAIT) LED_A_OFF(); // Error
274
275 return FALSE;
276 }
277
278 //-----------------------------------------------------------------------------
279 // Receive a command (from the reader to us, where we are the simulated tag),
280 // and store it in the given buffer, up to the given maximum length. Keeps
281 // spinning, waiting for a well-framed command, until either we get one
282 // (returns TRUE) or someone presses the pushbutton on the board (FALSE).
283 //
284 // Assume that we're called with the SSC (to the FPGA) and ADC path set
285 // correctly.
286 //-----------------------------------------------------------------------------
287 static int GetIso14443CommandFromReader(uint8_t *received, int *len, int maxLen)
288 {
289 uint8_t mask;
290 int i, bit;
291
292 // Set FPGA mode to "simulated ISO 14443 tag", no modulation (listen
293 // only, since we are receiving, not transmitting).
294 // Signal field is off with the appropriate LED
295 LED_D_OFF();
296 FpgaWriteConfWord(
297 FPGA_MAJOR_MODE_HF_SIMULATOR | FPGA_HF_SIMULATOR_NO_MODULATION);
298
299
300 // Now run a `software UART' on the stream of incoming samples.
301 Uart.output = received;
302 Uart.byteCntMax = maxLen;
303 Uart.state = STATE_UNSYNCD;
304
305 for(;;) {
306 WDT_HIT();
307
308 if(BUTTON_PRESS()) return FALSE;
309
310 if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
311 AT91C_BASE_SSC->SSC_THR = 0x00;
312 }
313 if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
314 uint8_t b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
315
316 mask = 0x80;
317 for(i = 0; i < 8; i++, mask >>= 1) {
318 bit = (b & mask);
319 if(Handle14443UartBit(bit)) {
320 *len = Uart.byteCnt;
321 return TRUE;
322 }
323 }
324 }
325 }
326 }
327
328 //-----------------------------------------------------------------------------
329 // Main loop of simulated tag: receive commands from reader, decide what
330 // response to send, and send it.
331 //-----------------------------------------------------------------------------
332 void SimulateIso14443Tag(void)
333 {
334 static const uint8_t cmd1[] = { 0x05, 0x00, 0x08, 0x39, 0x73 };
335 static const uint8_t response1[] = {
336 0x50, 0x82, 0x0d, 0xe1, 0x74, 0x20, 0x38, 0x19, 0x22,
337 0x00, 0x21, 0x85, 0x5e, 0xd7
338 };
339
340 uint8_t *resp;
341 int respLen;
342
343 uint8_t *resp1 = (((uint8_t *)BigBuf) + 800);
344 int resp1Len;
345
346 uint8_t *receivedCmd = (uint8_t *)BigBuf;
347 int len;
348
349 int i;
350
351 int cmdsRecvd = 0;
352
353 memset(receivedCmd, 0x44, 400);
354
355 CodeIso14443bAsTag(response1, sizeof(response1));
356 memcpy(resp1, ToSend, ToSendMax); resp1Len = ToSendMax;
357
358 // We need to listen to the high-frequency, peak-detected path.
359 SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
360 FpgaSetupSsc();
361
362 cmdsRecvd = 0;
363
364 for(;;) {
365 uint8_t b1, b2;
366
367 if(!GetIso14443CommandFromReader(receivedCmd, &len, 100)) {
368 Dbprintf("button pressed, received %d commands", cmdsRecvd);
369 break;
370 }
371
372 // Good, look at the command now.
373
374 if(len == sizeof(cmd1) && memcmp(receivedCmd, cmd1, len)==0) {
375 resp = resp1; respLen = resp1Len;
376 } else {
377 Dbprintf("new cmd from reader: len=%d, cmdsRecvd=%d", len, cmdsRecvd);
378 // And print whether the CRC fails, just for good measure
379 ComputeCrc14443(CRC_14443_B, receivedCmd, len-2, &b1, &b2);
380 if(b1 != receivedCmd[len-2] || b2 != receivedCmd[len-1]) {
381 // Not so good, try again.
382 DbpString("+++CRC fail");
383 } else {
384 DbpString("CRC passes");
385 }
386 break;
387 }
388
389 memset(receivedCmd, 0x44, 32);
390
391 cmdsRecvd++;
392
393 if(cmdsRecvd > 0x30) {
394 DbpString("many commands later...");
395 break;
396 }
397
398 if(respLen <= 0) continue;
399
400 // Modulate BPSK
401 // Signal field is off with the appropriate LED
402 LED_D_OFF();
403 FpgaWriteConfWord(
404 FPGA_MAJOR_MODE_HF_SIMULATOR | FPGA_HF_SIMULATOR_MODULATE_BPSK);
405 AT91C_BASE_SSC->SSC_THR = 0xff;
406 FpgaSetupSsc();
407
408 // Transmit the response.
409 i = 0;
410 for(;;) {
411 if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
412 uint8_t b = resp[i];
413
414 AT91C_BASE_SSC->SSC_THR = b;
415
416 i++;
417 if(i > respLen) {
418 break;
419 }
420 }
421 if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
422 volatile uint8_t b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
423 (void)b;
424 }
425 }
426 }
427 }
428
429 //=============================================================================
430 // An ISO 14443 Type B reader. We take layer two commands, code them
431 // appropriately, and then send them to the tag. We then listen for the
432 // tag's response, which we leave in the buffer to be demodulated on the
433 // PC side.
434 //=============================================================================
435
436 static struct {
437 enum {
438 DEMOD_UNSYNCD,
439 DEMOD_PHASE_REF_TRAINING,
440 DEMOD_AWAITING_FALLING_EDGE_OF_SOF,
441 DEMOD_GOT_FALLING_EDGE_OF_SOF,
442 DEMOD_AWAITING_START_BIT,
443 DEMOD_RECEIVING_DATA,
444 DEMOD_ERROR_WAIT
445 } state;
446 int bitCount;
447 int posCount;
448 int thisBit;
449 int metric;
450 int metricN;
451 uint16_t shiftReg;
452 uint8_t *output;
453 int len;
454 int sumI;
455 int sumQ;
456 } Demod;
457
458 /*
459 * Handles reception of a bit from the tag
460 *
461 * LED handling:
462 * LED C -> ON once we have received the SOF and are expecting the rest.
463 * LED C -> OFF once we have received EOF or are unsynced
464 *
465 * Returns: true if we received a EOF
466 * false if we are still waiting for some more
467 *
468 */
469 static RAMFUNC int Handle14443SamplesDemod(int ci, int cq)
470 {
471 int v;
472
473 // The soft decision on the bit uses an estimate of just the
474 // quadrant of the reference angle, not the exact angle.
475 #define MAKE_SOFT_DECISION() { \
476 if(Demod.sumI > 0) { \
477 v = ci; \
478 } else { \
479 v = -ci; \
480 } \
481 if(Demod.sumQ > 0) { \
482 v += cq; \
483 } else { \
484 v -= cq; \
485 } \
486 }
487
488 switch(Demod.state) {
489 case DEMOD_UNSYNCD:
490 v = ci;
491 if(v < 0) v = -v;
492 if(cq > 0) {
493 v += cq;
494 } else {
495 v -= cq;
496 }
497 if(v > 40) {
498 Demod.posCount = 0;
499 Demod.state = DEMOD_PHASE_REF_TRAINING;
500 Demod.sumI = 0;
501 Demod.sumQ = 0;
502 }
503 break;
504
505 case DEMOD_PHASE_REF_TRAINING:
506 if(Demod.posCount < 8) {
507 Demod.sumI += ci;
508 Demod.sumQ += cq;
509 } else if(Demod.posCount > 100) {
510 // error, waited too long
511 Demod.state = DEMOD_UNSYNCD;
512 } else {
513 MAKE_SOFT_DECISION();
514 if(v < 0) {
515 Demod.state = DEMOD_AWAITING_FALLING_EDGE_OF_SOF;
516 Demod.posCount = 0;
517 }
518 }
519 Demod.posCount++;
520 break;
521
522 case DEMOD_AWAITING_FALLING_EDGE_OF_SOF:
523 MAKE_SOFT_DECISION();
524 if(v < 0) {
525 Demod.state = DEMOD_GOT_FALLING_EDGE_OF_SOF;
526 Demod.posCount = 0;
527 } else {
528 if(Demod.posCount > 100) {
529 Demod.state = DEMOD_UNSYNCD;
530 }
531 }
532 Demod.posCount++;
533 break;
534
535 case DEMOD_GOT_FALLING_EDGE_OF_SOF:
536 MAKE_SOFT_DECISION();
537 if(v > 0) {
538 if(Demod.posCount < 12) {
539 Demod.state = DEMOD_UNSYNCD;
540 } else {
541 LED_C_ON(); // Got SOF
542 Demod.state = DEMOD_AWAITING_START_BIT;
543 Demod.posCount = 0;
544 Demod.len = 0;
545 Demod.metricN = 0;
546 Demod.metric = 0;
547 }
548 } else {
549 if(Demod.posCount > 100) {
550 Demod.state = DEMOD_UNSYNCD;
551 }
552 }
553 Demod.posCount++;
554 break;
555
556 case DEMOD_AWAITING_START_BIT:
557 MAKE_SOFT_DECISION();
558 if(v > 0) {
559 if(Demod.posCount > 10) {
560 Demod.state = DEMOD_UNSYNCD;
561 }
562 } else {
563 Demod.bitCount = 0;
564 Demod.posCount = 1;
565 Demod.thisBit = v;
566 Demod.shiftReg = 0;
567 Demod.state = DEMOD_RECEIVING_DATA;
568 }
569 break;
570
571 case DEMOD_RECEIVING_DATA:
572 MAKE_SOFT_DECISION();
573 if(Demod.posCount == 0) {
574 Demod.thisBit = v;
575 Demod.posCount = 1;
576 } else {
577 Demod.thisBit += v;
578
579 if(Demod.thisBit > 0) {
580 Demod.metric += Demod.thisBit;
581 } else {
582 Demod.metric -= Demod.thisBit;
583 }
584 (Demod.metricN)++;
585
586 Demod.shiftReg >>= 1;
587 if(Demod.thisBit > 0) {
588 Demod.shiftReg |= 0x200;
589 }
590
591 Demod.bitCount++;
592 if(Demod.bitCount == 10) {
593 uint16_t s = Demod.shiftReg;
594 if((s & 0x200) && !(s & 0x001)) {
595 uint8_t b = (s >> 1);
596 Demod.output[Demod.len] = b;
597 Demod.len++;
598 Demod.state = DEMOD_AWAITING_START_BIT;
599 } else if(s == 0x000) {
600 // This is EOF
601 LED_C_OFF();
602 Demod.state = DEMOD_UNSYNCD;
603 return TRUE;
604 } else {
605 Demod.state = DEMOD_UNSYNCD;
606 }
607 }
608 Demod.posCount = 0;
609 }
610 break;
611
612 default:
613 Demod.state = DEMOD_UNSYNCD;
614 break;
615 }
616
617 if (Demod.state == DEMOD_UNSYNCD) LED_C_OFF(); // Not synchronized...
618 return FALSE;
619 }
620
621 /*
622 * Demodulate the samples we received from the tag
623 * weTx: set to 'TRUE' if we behave like a reader
624 * set to 'FALSE' if we behave like a snooper
625 * quiet: set to 'TRUE' to disable debug output
626 */
627 static void GetSamplesFor14443Demod(int weTx, int n, int quiet)
628 {
629 int max = 0;
630 int gotFrame = FALSE;
631
632 //# define DMA_BUFFER_SIZE 8
633 int8_t *dmaBuf;
634
635 int lastRxCounter;
636 int8_t *upTo;
637
638 int ci, cq;
639
640 int samples = 0;
641
642 // Clear out the state of the "UART" that receives from the tag.
643 memset(BigBuf, 0x00, 400);
644 Demod.output = (uint8_t *)BigBuf;
645 Demod.len = 0;
646 Demod.state = DEMOD_UNSYNCD;
647
648 // And the UART that receives from the reader
649 Uart.output = (((uint8_t *)BigBuf) + 1024);
650 Uart.byteCntMax = 100;
651 Uart.state = STATE_UNSYNCD;
652
653 // Setup for the DMA.
654 dmaBuf = (int8_t *)(BigBuf + 32);
655 upTo = dmaBuf;
656 lastRxCounter = DEMOD_DMA_BUFFER_SIZE;
657 FpgaSetupSscDma((uint8_t *)dmaBuf, DEMOD_DMA_BUFFER_SIZE);
658
659 // Signal field is ON with the appropriate LED:
660 if (weTx) LED_D_ON(); else LED_D_OFF();
661 // And put the FPGA in the appropriate mode
662 FpgaWriteConfWord(
663 FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ |
664 (weTx ? 0 : FPGA_HF_READER_RX_XCORR_SNOOP));
665
666 for(;;) {
667 int behindBy = lastRxCounter - AT91C_BASE_PDC_SSC->PDC_RCR;
668 if(behindBy > max) max = behindBy;
669
670 while(((lastRxCounter-AT91C_BASE_PDC_SSC->PDC_RCR) & (DEMOD_DMA_BUFFER_SIZE-1))
671 > 2)
672 {
673 ci = upTo[0];
674 cq = upTo[1];
675 upTo += 2;
676 if(upTo - dmaBuf > DEMOD_DMA_BUFFER_SIZE) {
677 upTo -= DEMOD_DMA_BUFFER_SIZE;
678 AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) upTo;
679 AT91C_BASE_PDC_SSC->PDC_RNCR = DEMOD_DMA_BUFFER_SIZE;
680 }
681 lastRxCounter -= 2;
682 if(lastRxCounter <= 0) {
683 lastRxCounter += DEMOD_DMA_BUFFER_SIZE;
684 }
685
686 samples += 2;
687
688 Handle14443UartBit(1);
689 Handle14443UartBit(1);
690
691 if(Handle14443SamplesDemod(ci, cq)) {
692 gotFrame = 1;
693 }
694 }
695
696 if(samples > 2000) {
697 break;
698 }
699 }
700 AT91C_BASE_PDC_SSC->PDC_PTCR = AT91C_PDC_RXTDIS;
701 if (!quiet) Dbprintf("%x %x %x", max, gotFrame, Demod.len);
702 }
703
704 //-----------------------------------------------------------------------------
705 // Read the tag's response. We just receive a stream of slightly-processed
706 // samples from the FPGA, which we will later do some signal processing on,
707 // to get the bits.
708 //-----------------------------------------------------------------------------
709 /*static void GetSamplesFor14443(int weTx, int n)
710 {
711 uint8_t *dest = (uint8_t *)BigBuf;
712 int c;
713
714 FpgaWriteConfWord(
715 FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ |
716 (weTx ? 0 : FPGA_HF_READER_RX_XCORR_SNOOP));
717
718 c = 0;
719 for(;;) {
720 if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
721 AT91C_BASE_SSC->SSC_THR = 0x43;
722 }
723 if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
724 int8_t b;
725 b = (int8_t)AT91C_BASE_SSC->SSC_RHR;
726
727 dest[c++] = (uint8_t)b;
728
729 if(c >= n) {
730 break;
731 }
732 }
733 }
734 }*/
735
736 //-----------------------------------------------------------------------------
737 // Transmit the command (to the tag) that was placed in ToSend[].
738 //-----------------------------------------------------------------------------
739 static void TransmitFor14443(void)
740 {
741 int c;
742
743 FpgaSetupSsc();
744
745 while(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
746 AT91C_BASE_SSC->SSC_THR = 0xff;
747 }
748
749 // Signal field is ON with the appropriate Red LED
750 LED_D_ON();
751 // Signal we are transmitting with the Green LED
752 LED_B_ON();
753 FpgaWriteConfWord(
754 FPGA_MAJOR_MODE_HF_READER_TX | FPGA_HF_READER_TX_SHALLOW_MOD);
755
756 for(c = 0; c < 10;) {
757 if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
758 AT91C_BASE_SSC->SSC_THR = 0xff;
759 c++;
760 }
761 if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
762 volatile uint32_t r = AT91C_BASE_SSC->SSC_RHR;
763 (void)r;
764 }
765 WDT_HIT();
766 }
767
768 c = 0;
769 for(;;) {
770 if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
771 AT91C_BASE_SSC->SSC_THR = ToSend[c];
772 c++;
773 if(c >= ToSendMax) {
774 break;
775 }
776 }
777 if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
778 volatile uint32_t r = AT91C_BASE_SSC->SSC_RHR;
779 (void)r;
780 }
781 WDT_HIT();
782 }
783 LED_B_OFF(); // Finished sending
784 }
785
786 //-----------------------------------------------------------------------------
787 // Code a layer 2 command (string of octets, including CRC) into ToSend[],
788 // so that it is ready to transmit to the tag using TransmitFor14443().
789 //-----------------------------------------------------------------------------
790 static void CodeIso14443bAsReader(const uint8_t *cmd, int len)
791 {
792 int i, j;
793 uint8_t b;
794
795 ToSendReset();
796
797 // Establish initial reference level
798 for(i = 0; i < 40; i++) {
799 ToSendStuffBit(1);
800 }
801 // Send SOF
802 for(i = 0; i < 10; i++) {
803 ToSendStuffBit(0);
804 }
805
806 for(i = 0; i < len; i++) {
807 // Stop bits/EGT
808 ToSendStuffBit(1);
809 ToSendStuffBit(1);
810 // Start bit
811 ToSendStuffBit(0);
812 // Data bits
813 b = cmd[i];
814 for(j = 0; j < 8; j++) {
815 if(b & 1) {
816 ToSendStuffBit(1);
817 } else {
818 ToSendStuffBit(0);
819 }
820 b >>= 1;
821 }
822 }
823 // Send EOF
824 ToSendStuffBit(1);
825 for(i = 0; i < 10; i++) {
826 ToSendStuffBit(0);
827 }
828 for(i = 0; i < 8; i++) {
829 ToSendStuffBit(1);
830 }
831
832 // And then a little more, to make sure that the last character makes
833 // it out before we switch to rx mode.
834 for(i = 0; i < 24; i++) {
835 ToSendStuffBit(1);
836 }
837
838 // Convert from last character reference to length
839 ToSendMax++;
840 }
841
842 //-----------------------------------------------------------------------------
843 // Read an ISO 14443 tag. We send it some set of commands, and record the
844 // responses.
845 // The command name is misleading, it actually decodes the reponse in HEX
846 // into the output buffer (read the result using hexsamples, not hisamples)
847 //
848 // obsolete function only for test
849 //-----------------------------------------------------------------------------
850 void AcquireRawAdcSamplesIso14443(uint32_t parameter)
851 {
852 uint8_t cmd1[] = { 0x05, 0x00, 0x08, 0x39, 0x73 };
853
854 SendRawCommand14443B(sizeof(cmd1),1,1,cmd1);
855 }
856
857 //-----------------------------------------------------------------------------
858 // Read a SRI512 ISO 14443 tag.
859 //
860 // SRI512 tags are just simple memory tags, here we're looking at making a dump
861 // of the contents of the memory. No anticollision algorithm is done, we assume
862 // we have a single tag in the field.
863 //
864 // I tried to be systematic and check every answer of the tag, every CRC, etc...
865 //-----------------------------------------------------------------------------
866 void ReadSTMemoryIso14443(uint32_t dwLast)
867 {
868 uint8_t i = 0x00;
869
870 // Make sure that we start from off, since the tags are stateful;
871 // confusing things will happen if we don't reset them between reads.
872 LED_D_OFF();
873 FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
874 SpinDelay(200);
875
876 SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
877 FpgaSetupSsc();
878
879 // Now give it time to spin up.
880 // Signal field is on with the appropriate LED
881 LED_D_ON();
882 FpgaWriteConfWord(
883 FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ);
884 SpinDelay(200);
885
886 // First command: wake up the tag using the INITIATE command
887 uint8_t cmd1[] = { 0x06, 0x00, 0x97, 0x5b};
888 CodeIso14443bAsReader(cmd1, sizeof(cmd1));
889 TransmitFor14443();
890 // LED_A_ON();
891 GetSamplesFor14443Demod(TRUE, 2000,TRUE);
892 // LED_A_OFF();
893
894 if (Demod.len == 0) {
895 DbpString("No response from tag");
896 return;
897 } else {
898 Dbprintf("Randomly generated UID from tag (+ 2 byte CRC): %x %x %x",
899 Demod.output[0], Demod.output[1],Demod.output[2]);
900 }
901 // There is a response, SELECT the uid
902 DbpString("Now SELECT tag:");
903 cmd1[0] = 0x0E; // 0x0E is SELECT
904 cmd1[1] = Demod.output[0];
905 ComputeCrc14443(CRC_14443_B, cmd1, 2, &cmd1[2], &cmd1[3]);
906 CodeIso14443bAsReader(cmd1, sizeof(cmd1));
907 TransmitFor14443();
908 // LED_A_ON();
909 GetSamplesFor14443Demod(TRUE, 2000,TRUE);
910 // LED_A_OFF();
911 if (Demod.len != 3) {
912 Dbprintf("Expected 3 bytes from tag, got %d", Demod.len);
913 return;
914 }
915 // Check the CRC of the answer:
916 ComputeCrc14443(CRC_14443_B, Demod.output, 1 , &cmd1[2], &cmd1[3]);
917 if(cmd1[2] != Demod.output[1] || cmd1[3] != Demod.output[2]) {
918 DbpString("CRC Error reading select response.");
919 return;
920 }
921 // Check response from the tag: should be the same UID as the command we just sent:
922 if (cmd1[1] != Demod.output[0]) {
923 Dbprintf("Bad response to SELECT from Tag, aborting: %x %x", cmd1[1], Demod.output[0]);
924 return;
925 }
926 // Tag is now selected,
927 // First get the tag's UID:
928 cmd1[0] = 0x0B;
929 ComputeCrc14443(CRC_14443_B, cmd1, 1 , &cmd1[1], &cmd1[2]);
930 CodeIso14443bAsReader(cmd1, 3); // Only first three bytes for this one
931 TransmitFor14443();
932 // LED_A_ON();
933 GetSamplesFor14443Demod(TRUE, 2000,TRUE);
934 // LED_A_OFF();
935 if (Demod.len != 10) {
936 Dbprintf("Expected 10 bytes from tag, got %d", Demod.len);
937 return;
938 }
939 // The check the CRC of the answer (use cmd1 as temporary variable):
940 ComputeCrc14443(CRC_14443_B, Demod.output, 8, &cmd1[2], &cmd1[3]);
941 if(cmd1[2] != Demod.output[8] || cmd1[3] != Demod.output[9]) {
942 Dbprintf("CRC Error reading block! - Below: expected, got %x %x",
943 (cmd1[2]<<8)+cmd1[3], (Demod.output[8]<<8)+Demod.output[9]);
944 // Do not return;, let's go on... (we should retry, maybe ?)
945 }
946 Dbprintf("Tag UID (64 bits): %08x %08x",
947 (Demod.output[7]<<24) + (Demod.output[6]<<16) + (Demod.output[5]<<8) + Demod.output[4],
948 (Demod.output[3]<<24) + (Demod.output[2]<<16) + (Demod.output[1]<<8) + Demod.output[0]);
949
950 // Now loop to read all 16 blocks, address from 0 to last block
951 Dbprintf("Tag memory dump, block 0 to %d",dwLast);
952 cmd1[0] = 0x08;
953 i = 0x00;
954 dwLast++;
955 for (;;) {
956 if (i == dwLast) {
957 DbpString("System area block (0xff):");
958 i = 0xff;
959 }
960 cmd1[1] = i;
961 ComputeCrc14443(CRC_14443_B, cmd1, 2, &cmd1[2], &cmd1[3]);
962 CodeIso14443bAsReader(cmd1, sizeof(cmd1));
963 TransmitFor14443();
964 // LED_A_ON();
965 GetSamplesFor14443Demod(TRUE, 2000,TRUE);
966 // LED_A_OFF();
967 if (Demod.len != 6) { // Check if we got an answer from the tag
968 DbpString("Expected 6 bytes from tag, got less...");
969 return;
970 }
971 // The check the CRC of the answer (use cmd1 as temporary variable):
972 ComputeCrc14443(CRC_14443_B, Demod.output, 4, &cmd1[2], &cmd1[3]);
973 if(cmd1[2] != Demod.output[4] || cmd1[3] != Demod.output[5]) {
974 Dbprintf("CRC Error reading block! - Below: expected, got %x %x",
975 (cmd1[2]<<8)+cmd1[3], (Demod.output[4]<<8)+Demod.output[5]);
976 // Do not return;, let's go on... (we should retry, maybe ?)
977 }
978 // Now print out the memory location:
979 Dbprintf("Address=%x, Contents=%x, CRC=%x", i,
980 (Demod.output[3]<<24) + (Demod.output[2]<<16) + (Demod.output[1]<<8) + Demod.output[0],
981 (Demod.output[4]<<8)+Demod.output[5]);
982 if (i == 0xff) {
983 break;
984 }
985 i++;
986 }
987 }
988
989
990 //=============================================================================
991 // Finally, the `sniffer' combines elements from both the reader and
992 // simulated tag, to show both sides of the conversation.
993 //=============================================================================
994
995 //-----------------------------------------------------------------------------
996 // Record the sequence of commands sent by the reader to the tag, with
997 // triggering so that we start recording at the point that the tag is moved
998 // near the reader.
999 //-----------------------------------------------------------------------------
1000 /*
1001 * Memory usage for this function, (within BigBuf)
1002 * 0-4095 : Demodulated samples receive (4096 bytes) - DEMOD_TRACE_SIZE
1003 * 4096-6143 : Last Received command, 2048 bytes (reader->tag) - READER_TAG_BUFFER_SIZE
1004 * 6144-8191 : Last Received command, 2048 bytes(tag->reader) - TAG_READER_BUFFER_SIZE
1005 * 8192-9215 : DMA Buffer, 1024 bytes (samples) - DEMOD_DMA_BUFFER_SIZE
1006 */
1007 void RAMFUNC SnoopIso14443(void)
1008 {
1009 // We won't start recording the frames that we acquire until we trigger;
1010 // a good trigger condition to get started is probably when we see a
1011 // response from the tag.
1012 int triggered = TRUE;
1013
1014 // The command (reader -> tag) that we're working on receiving.
1015 uint8_t *receivedCmd = (uint8_t *)(BigBuf) + DEMOD_TRACE_SIZE;
1016 // The response (tag -> reader) that we're working on receiving.
1017 uint8_t *receivedResponse = (uint8_t *)(BigBuf) + DEMOD_TRACE_SIZE + READER_TAG_BUFFER_SIZE;
1018
1019 // As we receive stuff, we copy it from receivedCmd or receivedResponse
1020 // into trace, along with its length and other annotations.
1021 uint8_t *trace = (uint8_t *)BigBuf;
1022 int traceLen = 0;
1023
1024 // The DMA buffer, used to stream samples from the FPGA.
1025 int8_t *dmaBuf = (int8_t *)(BigBuf) + DEMOD_TRACE_SIZE + READER_TAG_BUFFER_SIZE + TAG_READER_BUFFER_SIZE;
1026 int lastRxCounter;
1027 int8_t *upTo;
1028 int ci, cq;
1029 int maxBehindBy = 0;
1030
1031 // Count of samples received so far, so that we can include timing
1032 // information in the trace buffer.
1033 int samples = 0;
1034
1035 // Initialize the trace buffer
1036 memset(trace, 0x44, DEMOD_TRACE_SIZE);
1037
1038 // Set up the demodulator for tag -> reader responses.
1039 Demod.output = receivedResponse;
1040 Demod.len = 0;
1041 Demod.state = DEMOD_UNSYNCD;
1042
1043 // And the reader -> tag commands
1044 memset(&Uart, 0, sizeof(Uart));
1045 Uart.output = receivedCmd;
1046 Uart.byteCntMax = 100;
1047 Uart.state = STATE_UNSYNCD;
1048
1049 // Print some debug information about the buffer sizes
1050 Dbprintf("Snooping buffers initialized:");
1051 Dbprintf(" Trace: %i bytes", DEMOD_TRACE_SIZE);
1052 Dbprintf(" Reader -> tag: %i bytes", READER_TAG_BUFFER_SIZE);
1053 Dbprintf(" tag -> Reader: %i bytes", TAG_READER_BUFFER_SIZE);
1054 Dbprintf(" DMA: %i bytes", DEMOD_DMA_BUFFER_SIZE);
1055
1056 // And put the FPGA in the appropriate mode
1057 // Signal field is off with the appropriate LED
1058 LED_D_OFF();
1059 FpgaWriteConfWord(
1060 FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ |
1061 FPGA_HF_READER_RX_XCORR_SNOOP);
1062 SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
1063
1064 // Setup for the DMA.
1065 FpgaSetupSsc();
1066 upTo = dmaBuf;
1067 lastRxCounter = DEMOD_DMA_BUFFER_SIZE;
1068 FpgaSetupSscDma((uint8_t *)dmaBuf, DEMOD_DMA_BUFFER_SIZE);
1069
1070 LED_A_ON();
1071
1072 // And now we loop, receiving samples.
1073 for(;;) {
1074 int behindBy = (lastRxCounter - AT91C_BASE_PDC_SSC->PDC_RCR) &
1075 (DEMOD_DMA_BUFFER_SIZE-1);
1076 if(behindBy > maxBehindBy) {
1077 maxBehindBy = behindBy;
1078 if(behindBy > (DEMOD_DMA_BUFFER_SIZE-2)) { // TODO: understand whether we can increase/decrease as we want or not?
1079 Dbprintf("blew circular buffer! behindBy=0x%x", behindBy);
1080 goto done;
1081 }
1082 }
1083 if(behindBy < 2) continue;
1084
1085 ci = upTo[0];
1086 cq = upTo[1];
1087 upTo += 2;
1088 lastRxCounter -= 2;
1089 if(upTo - dmaBuf > DEMOD_DMA_BUFFER_SIZE) {
1090 upTo -= DEMOD_DMA_BUFFER_SIZE;
1091 lastRxCounter += DEMOD_DMA_BUFFER_SIZE;
1092 AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) upTo;
1093 AT91C_BASE_PDC_SSC->PDC_RNCR = DEMOD_DMA_BUFFER_SIZE;
1094 }
1095
1096 samples += 2;
1097
1098 #define HANDLE_BIT_IF_BODY \
1099 if(triggered) { \
1100 trace[traceLen++] = ((samples >> 0) & 0xff); \
1101 trace[traceLen++] = ((samples >> 8) & 0xff); \
1102 trace[traceLen++] = ((samples >> 16) & 0xff); \
1103 trace[traceLen++] = ((samples >> 24) & 0xff); \
1104 trace[traceLen++] = 0; \
1105 trace[traceLen++] = 0; \
1106 trace[traceLen++] = 0; \
1107 trace[traceLen++] = 0; \
1108 trace[traceLen++] = Uart.byteCnt; \
1109 memcpy(trace+traceLen, receivedCmd, Uart.byteCnt); \
1110 traceLen += Uart.byteCnt; \
1111 if(traceLen > 1000) break; \
1112 } \
1113 /* And ready to receive another command. */ \
1114 memset(&Uart, 0, sizeof(Uart)); \
1115 Uart.output = receivedCmd; \
1116 Uart.byteCntMax = 100; \
1117 Uart.state = STATE_UNSYNCD; \
1118 /* And also reset the demod code, which might have been */ \
1119 /* false-triggered by the commands from the reader. */ \
1120 memset(&Demod, 0, sizeof(Demod)); \
1121 Demod.output = receivedResponse; \
1122 Demod.state = DEMOD_UNSYNCD; \
1123
1124 if(Handle14443UartBit(ci & 1)) {
1125 HANDLE_BIT_IF_BODY
1126 }
1127 if(Handle14443UartBit(cq & 1)) {
1128 HANDLE_BIT_IF_BODY
1129 }
1130
1131 if(Handle14443SamplesDemod(ci, cq)) {
1132 // timestamp, as a count of samples
1133 trace[traceLen++] = ((samples >> 0) & 0xff);
1134 trace[traceLen++] = ((samples >> 8) & 0xff);
1135 trace[traceLen++] = ((samples >> 16) & 0xff);
1136 trace[traceLen++] = 0x80 | ((samples >> 24) & 0xff);
1137 // correlation metric (~signal strength estimate)
1138 if(Demod.metricN != 0) {
1139 Demod.metric /= Demod.metricN;
1140 }
1141 trace[traceLen++] = ((Demod.metric >> 0) & 0xff);
1142 trace[traceLen++] = ((Demod.metric >> 8) & 0xff);
1143 trace[traceLen++] = ((Demod.metric >> 16) & 0xff);
1144 trace[traceLen++] = ((Demod.metric >> 24) & 0xff);
1145 // length
1146 trace[traceLen++] = Demod.len;
1147 memcpy(trace+traceLen, receivedResponse, Demod.len);
1148 traceLen += Demod.len;
1149 if(traceLen > DEMOD_TRACE_SIZE) {
1150 DbpString("Reached trace limit");
1151 goto done;
1152 }
1153
1154 triggered = TRUE;
1155 LED_A_OFF();
1156 LED_B_ON();
1157
1158 // And ready to receive another response.
1159 memset(&Demod, 0, sizeof(Demod));
1160 Demod.output = receivedResponse;
1161 Demod.state = DEMOD_UNSYNCD;
1162 }
1163 WDT_HIT();
1164
1165 if(BUTTON_PRESS()) {
1166 DbpString("cancelled");
1167 goto done;
1168 }
1169 }
1170
1171 done:
1172 LED_A_OFF();
1173 LED_B_OFF();
1174 LED_C_OFF();
1175 AT91C_BASE_PDC_SSC->PDC_PTCR = AT91C_PDC_RXTDIS;
1176 DbpString("Snoop statistics:");
1177 Dbprintf(" Max behind by: %i", maxBehindBy);
1178 Dbprintf(" Uart State: %x", Uart.state);
1179 Dbprintf(" Uart ByteCnt: %i", Uart.byteCnt);
1180 Dbprintf(" Uart ByteCntMax: %i", Uart.byteCntMax);
1181 Dbprintf(" Trace length: %i", traceLen);
1182 }
1183
1184 /*
1185 * Send raw command to tag ISO14443B
1186 * @Input
1187 * datalen len of buffer data
1188 * recv bool when true wait for data from tag and send to client
1189 * powerfield bool leave the field on when true
1190 * data buffer with byte to send
1191 *
1192 * @Output
1193 * none
1194 *
1195 */
1196
1197 void SendRawCommand14443B(uint32_t datalen, uint32_t recv,uint8_t powerfield, uint8_t data[])
1198 {
1199 if(!powerfield)
1200 {
1201 // Make sure that we start from off, since the tags are stateful;
1202 // confusing things will happen if we don't reset them between reads.
1203 FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
1204 LED_D_OFF();
1205 SpinDelay(200);
1206 }
1207
1208 if(!GETBIT(GPIO_LED_D))
1209 {
1210 SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
1211 FpgaSetupSsc();
1212
1213 // Now give it time to spin up.
1214 // Signal field is on with the appropriate LED
1215 LED_D_ON();
1216 FpgaWriteConfWord(
1217 FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ);
1218 SpinDelay(200);
1219 }
1220
1221 CodeIso14443bAsReader(data, datalen);
1222 TransmitFor14443();
1223 if(recv)
1224 {
1225 uint16_t iLen = MIN(Demod.len,USB_CMD_DATA_SIZE);
1226 GetSamplesFor14443Demod(TRUE, 2000, TRUE);
1227 cmd_send(CMD_ACK,iLen,0,0,Demod.output,iLen);
1228 }
1229 if(!powerfield)
1230 {
1231 FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
1232 LED_D_OFF();
1233 }
1234 }
1235
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