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1 //-----------------------------------------------------------------------------
2 // This code is licensed to you under the terms of the GNU GPL, version 2 or,
3 // at your option, any later version. See the LICENSE.txt file for the text of
4 // the license.
5 //-----------------------------------------------------------------------------
6 // Hitag2 emulation (preliminary test version)
7 //
8 // (c) 2009 Henryk Plötz <henryk@ploetzli.ch>
9 //-----------------------------------------------------------------------------
10 // Hitag2 complete rewrite of the code
11 // - Fixed modulation/encoding issues
12 // - Rewrote code for transponder emulation
13 // - Added snooping of transponder communication
14 // - Added reader functionality
15 //
16 // (c) 2012 Roel Verdult
17 //-----------------------------------------------------------------------------
18
19 #include "proxmark3.h"
20 #include "apps.h"
21 #include "util.h"
22 #include "hitag2.h"
23 #include "string.h"
24
25 static bool bQuiet;
26
27 bool bCrypto;
28 bool bAuthenticating;
29 bool bPwd;
30 bool bSuccessful;
31
32 struct hitag2_tag {
33 uint32_t uid;
34 enum {
35 TAG_STATE_RESET = 0x01, // Just powered up, awaiting GetSnr
36 TAG_STATE_ACTIVATING = 0x02 , // In activation phase (password mode), sent UID, awaiting reader password
37 TAG_STATE_ACTIVATED = 0x03, // Activation complete, awaiting read/write commands
38 TAG_STATE_WRITING = 0x04, // In write command, awaiting sector contents to be written
39 } state;
40 unsigned int active_sector;
41 byte_t crypto_active;
42 uint64_t cs;
43 byte_t sectors[12][4];
44 };
45
46 static struct hitag2_tag tag = {
47 .state = TAG_STATE_RESET,
48 .sectors = { // Password mode: | Crypto mode:
49 [0] = { 0x02, 0x4e, 0x02, 0x20}, // UID | UID
50 [1] = { 0x4d, 0x49, 0x4b, 0x52}, // Password RWD | 32 bit LSB key
51 [2] = { 0x20, 0xf0, 0x4f, 0x4e}, // Reserved | 16 bit MSB key, 16 bit reserved
52 [3] = { 0x0e, 0xaa, 0x48, 0x54}, // Configuration, password TAG | Configuration, password TAG
53 [4] = { 0x46, 0x5f, 0x4f, 0x4b}, // Data: F_OK
54 [5] = { 0x55, 0x55, 0x55, 0x55}, // Data: UUUU
55 [6] = { 0xaa, 0xaa, 0xaa, 0xaa}, // Data: ....
56 [7] = { 0x55, 0x55, 0x55, 0x55}, // Data: UUUU
57 [8] = { 0x00, 0x00, 0x00, 0x00}, // RSK Low
58 [9] = { 0x00, 0x00, 0x00, 0x00}, // RSK High
59 [10] = { 0x00, 0x00, 0x00, 0x00}, // RCF
60 [11] = { 0x00, 0x00, 0x00, 0x00}, // SYNC
61 },
62 };
63
64 //#define TRACE_LENGTH 3000
65 //uint8_t *trace = (uint8_t *) BigBuf;
66 //int traceLen = 0;
67 //int rsamples = 0;
68
69 #define AUTH_TABLE_OFFSET FREE_BUFFER_OFFSET
70 #define AUTH_TABLE_LENGTH FREE_BUFFER_SIZE
71 byte_t* auth_table = (byte_t *)BigBuf+AUTH_TABLE_OFFSET;
72 size_t auth_table_pos = 0;
73 size_t auth_table_len = AUTH_TABLE_LENGTH;
74
75 byte_t password[4];
76 byte_t NrAr[8];
77 byte_t key[8];
78 uint64_t cipher_state;
79
80 /* Following is a modified version of cryptolib.com/ciphers/hitag2/ */
81 // Software optimized 48-bit Philips/NXP Mifare Hitag2 PCF7936/46/47/52 stream cipher algorithm by I.C. Wiener 2006-2007.
82 // For educational purposes only.
83 // No warranties or guarantees of any kind.
84 // This code is released into the public domain by its author.
85
86 // Basic macros:
87
88 #define u8 uint8_t
89 #define u32 uint32_t
90 #define u64 uint64_t
91 #define rev8(x) ((((x)>>7)&1)+((((x)>>6)&1)<<1)+((((x)>>5)&1)<<2)+((((x)>>4)&1)<<3)+((((x)>>3)&1)<<4)+((((x)>>2)&1)<<5)+((((x)>>1)&1)<<6)+(((x)&1)<<7))
92 #define rev16(x) (rev8 (x)+(rev8 (x>> 8)<< 8))
93 #define rev32(x) (rev16(x)+(rev16(x>>16)<<16))
94 #define rev64(x) (rev32(x)+(rev32(x>>32)<<32))
95 #define bit(x,n) (((x)>>(n))&1)
96 #define bit32(x,n) ((((x)[(n)>>5])>>((n)))&1)
97 #define inv32(x,i,n) ((x)[(i)>>5]^=((u32)(n))<<((i)&31))
98 #define rotl64(x, n) ((((u64)(x))<<((n)&63))+(((u64)(x))>>((0-(n))&63)))
99
100 // Single bit Hitag2 functions:
101
102 #define i4(x,a,b,c,d) ((u32)((((x)>>(a))&1)+(((x)>>(b))&1)*2+(((x)>>(c))&1)*4+(((x)>>(d))&1)*8))
103
104 static const u32 ht2_f4a = 0x2C79; // 0010 1100 0111 1001
105 static const u32 ht2_f4b = 0x6671; // 0110 0110 0111 0001
106 static const u32 ht2_f5c = 0x7907287B; // 0111 1001 0000 0111 0010 1000 0111 1011
107
108 static u32 _f20 (const u64 x)
109 {
110 u32 i5;
111
112 i5 = ((ht2_f4a >> i4 (x, 1, 2, 4, 5)) & 1)* 1
113 + ((ht2_f4b >> i4 (x, 7,11,13,14)) & 1)* 2
114 + ((ht2_f4b >> i4 (x,16,20,22,25)) & 1)* 4
115 + ((ht2_f4b >> i4 (x,27,28,30,32)) & 1)* 8
116 + ((ht2_f4a >> i4 (x,33,42,43,45)) & 1)*16;
117
118 return (ht2_f5c >> i5) & 1;
119 }
120
121 static u64 _hitag2_init (const u64 key, const u32 serial, const u32 IV)
122 {
123 u32 i;
124 u64 x = ((key & 0xFFFF) << 32) + serial;
125
126 for (i = 0; i < 32; i++)
127 {
128 x >>= 1;
129 x += (u64) (_f20 (x) ^ (((IV >> i) ^ (key >> (i+16))) & 1)) << 47;
130 }
131 return x;
132 }
133
134 static u64 _hitag2_round (u64 *state)
135 {
136 u64 x = *state;
137
138 x = (x >> 1) +
139 ((((x >> 0) ^ (x >> 2) ^ (x >> 3) ^ (x >> 6)
140 ^ (x >> 7) ^ (x >> 8) ^ (x >> 16) ^ (x >> 22)
141 ^ (x >> 23) ^ (x >> 26) ^ (x >> 30) ^ (x >> 41)
142 ^ (x >> 42) ^ (x >> 43) ^ (x >> 46) ^ (x >> 47)) & 1) << 47);
143
144 *state = x;
145 return _f20 (x);
146 }
147
148 static u32 _hitag2_byte (u64 * x)
149 {
150 u32 i, c;
151
152 for (i = 0, c = 0; i < 8; i++) c += (u32) _hitag2_round (x) << (i^7);
153 return c;
154 }
155
156 size_t nbytes(size_t nbits) {
157 return (nbits/8)+((nbits%8)>0);
158 }
159
160 int hitag2_reset(void)
161 {
162 tag.state = TAG_STATE_RESET;
163 tag.crypto_active = 0;
164 return 0;
165 }
166
167 int hitag2_init(void)
168 {
169 // memcpy(&tag, &resetdata, sizeof(tag));
170 hitag2_reset();
171 return 0;
172 }
173
174 static void hitag2_cipher_reset(struct hitag2_tag *tag, const byte_t *iv)
175 {
176 uint64_t key = ((uint64_t)tag->sectors[2][2]) |
177 ((uint64_t)tag->sectors[2][3] << 8) |
178 ((uint64_t)tag->sectors[1][0] << 16) |
179 ((uint64_t)tag->sectors[1][1] << 24) |
180 ((uint64_t)tag->sectors[1][2] << 32) |
181 ((uint64_t)tag->sectors[1][3] << 40);
182 uint32_t uid = ((uint32_t)tag->sectors[0][0]) |
183 ((uint32_t)tag->sectors[0][1] << 8) |
184 ((uint32_t)tag->sectors[0][2] << 16) |
185 ((uint32_t)tag->sectors[0][3] << 24);
186 uint32_t iv_ = (((uint32_t)(iv[0]))) |
187 (((uint32_t)(iv[1])) << 8) |
188 (((uint32_t)(iv[2])) << 16) |
189 (((uint32_t)(iv[3])) << 24);
190 tag->cs = _hitag2_init(rev64(key), rev32(uid), rev32(iv_));
191 }
192
193 static int hitag2_cipher_authenticate(uint64_t* cs, const byte_t *authenticator_is)
194 {
195 byte_t authenticator_should[4];
196 authenticator_should[0] = ~_hitag2_byte(cs);
197 authenticator_should[1] = ~_hitag2_byte(cs);
198 authenticator_should[2] = ~_hitag2_byte(cs);
199 authenticator_should[3] = ~_hitag2_byte(cs);
200 return (memcmp(authenticator_should, authenticator_is, 4) == 0);
201 }
202
203 static int hitag2_cipher_transcrypt(uint64_t* cs, byte_t *data, unsigned int bytes, unsigned int bits)
204 {
205 int i;
206 for(i=0; i<bytes; i++) data[i] ^= _hitag2_byte(cs);
207 for(i=0; i<bits; i++) data[bytes] ^= _hitag2_round(cs) << (7-i);
208 return 0;
209 }
210
211 // Sam7s has several timers, we will use the source TIMER_CLOCK1 (aka AT91C_TC_CLKS_TIMER_DIV1_CLOCK)
212 // TIMER_CLOCK1 = MCK/2, MCK is running at 48 MHz, Timer is running at 48/2 = 24 MHz
213 // Hitag units (T0) have duration of 8 microseconds (us), which is 1/125000 per second (carrier)
214 // T0 = TIMER_CLOCK1 / 125000 = 192
215 #define T0 192
216
217 #define SHORT_COIL() LOW(GPIO_SSC_DOUT)
218 #define OPEN_COIL() HIGH(GPIO_SSC_DOUT)
219
220 #define HITAG_FRAME_LEN 20
221 #define HITAG_T_STOP 36 /* T_EOF should be > 36 */
222 #define HITAG_T_LOW 8 /* T_LOW should be 4..10 */
223 #define HITAG_T_0_MIN 15 /* T[0] should be 18..22 */
224 #define HITAG_T_1_MIN 25 /* T[1] should be 26..30 */
225 //#define HITAG_T_EOF 40 /* T_EOF should be > 36 */
226 #define HITAG_T_EOF 80 /* T_EOF should be > 36 */
227 #define HITAG_T_WAIT_1 200 /* T_wresp should be 199..206 */
228 #define HITAG_T_WAIT_2 90 /* T_wresp should be 199..206 */
229 #define HITAG_T_WAIT_MAX 300 /* bit more than HITAG_T_WAIT_1 + HITAG_T_WAIT_2 */
230
231 #define HITAG_T_TAG_ONE_HALF_PERIOD 10
232 #define HITAG_T_TAG_TWO_HALF_PERIOD 25
233 #define HITAG_T_TAG_THREE_HALF_PERIOD 41
234 #define HITAG_T_TAG_FOUR_HALF_PERIOD 57
235
236 #define HITAG_T_TAG_HALF_PERIOD 16
237 #define HITAG_T_TAG_FULL_PERIOD 32
238
239 #define HITAG_T_TAG_CAPTURE_ONE_HALF 13
240 #define HITAG_T_TAG_CAPTURE_TWO_HALF 25
241 #define HITAG_T_TAG_CAPTURE_THREE_HALF 41
242 #define HITAG_T_TAG_CAPTURE_FOUR_HALF 57
243
244
245 static void hitag_send_bit(int bit) {
246 LED_A_ON();
247 // Reset clock for the next bit
248 AT91C_BASE_TC0->TC_CCR = AT91C_TC_SWTRG;
249
250 // Fixed modulation, earlier proxmark version used inverted signal
251 if(bit == 0) {
252 // Manchester: Unloaded, then loaded |__--|
253 LOW(GPIO_SSC_DOUT);
254 while(AT91C_BASE_TC0->TC_CV < T0*HITAG_T_TAG_HALF_PERIOD);
255 HIGH(GPIO_SSC_DOUT);
256 while(AT91C_BASE_TC0->TC_CV < T0*HITAG_T_TAG_FULL_PERIOD);
257 } else {
258 // Manchester: Loaded, then unloaded |--__|
259 HIGH(GPIO_SSC_DOUT);
260 while(AT91C_BASE_TC0->TC_CV < T0*HITAG_T_TAG_HALF_PERIOD);
261 LOW(GPIO_SSC_DOUT);
262 while(AT91C_BASE_TC0->TC_CV < T0*HITAG_T_TAG_FULL_PERIOD);
263 }
264 LED_A_OFF();
265 }
266
267 static void hitag_send_frame(const byte_t* frame, size_t frame_len)
268 {
269 // Send start of frame
270 for(size_t i=0; i<5; i++) {
271 hitag_send_bit(1);
272 }
273
274 // Send the content of the frame
275 for(size_t i=0; i<frame_len; i++) {
276 hitag_send_bit((frame[i/8] >> (7-(i%8)))&1);
277 }
278
279 // Drop the modulation
280 LOW(GPIO_SSC_DOUT);
281 }
282
283 void hitag2_handle_reader_command(byte_t* rx, const size_t rxlen, byte_t* tx, size_t* txlen)
284 {
285 byte_t rx_air[HITAG_FRAME_LEN];
286
287 // Copy the (original) received frame how it is send over the air
288 memcpy(rx_air,rx,nbytes(rxlen));
289
290 if(tag.crypto_active) {
291 hitag2_cipher_transcrypt(&(tag.cs),rx,rxlen/8,rxlen%8);
292 }
293
294 // Reset the transmission frame length
295 *txlen = 0;
296
297 // Try to find out which command was send by selecting on length (in bits)
298 switch (rxlen) {
299 // Received 11000 from the reader, request for UID, send UID
300 case 05: {
301 // Always send over the air in the clear plaintext mode
302 if(rx_air[0] != 0xC0) {
303 // Unknown frame ?
304 return;
305 }
306 *txlen = 32;
307 memcpy(tx,tag.sectors[0],4);
308 tag.crypto_active = 0;
309 }
310 break;
311
312 // Read/Write command: ..xx x..y yy with yyy == ~xxx, xxx is sector number
313 case 10: {
314 unsigned int sector = (~( ((rx[0]<<2)&0x04) | ((rx[1]>>6)&0x03) ) & 0x07);
315 // Verify complement of sector index
316 if(sector != ((rx[0]>>3)&0x07)) {
317 //DbpString("Transmission error (read/write)");
318 return;
319 }
320
321 switch (rx[0] & 0xC6) {
322 // Read command: 11xx x00y
323 case 0xC0:
324 memcpy(tx,tag.sectors[sector],4);
325 *txlen = 32;
326 break;
327
328 // Inverted Read command: 01xx x10y
329 case 0x44:
330 for (size_t i=0; i<4; i++) {
331 tx[i] = tag.sectors[sector][i] ^ 0xff;
332 }
333 *txlen = 32;
334 break;
335
336 // Write command: 10xx x01y
337 case 0x82:
338 // Prepare write, acknowledge by repeating command
339 memcpy(tx,rx,nbytes(rxlen));
340 *txlen = rxlen;
341 tag.active_sector = sector;
342 tag.state=TAG_STATE_WRITING;
343 break;
344
345 // Unknown command
346 default:
347 Dbprintf("Uknown command: %02x %02x",rx[0],rx[1]);
348 return;
349 break;
350 }
351 }
352 break;
353
354 // Writing data or Reader password
355 case 32: {
356 if(tag.state == TAG_STATE_WRITING) {
357 // These are the sector contents to be written. We don't have to do anything else.
358 memcpy(tag.sectors[tag.active_sector],rx,nbytes(rxlen));
359 tag.state=TAG_STATE_RESET;
360 return;
361 } else {
362 // Received RWD password, respond with configuration and our password
363 if(memcmp(rx,tag.sectors[1],4) != 0) {
364 DbpString("Reader password is wrong");
365 return;
366 }
367 *txlen = 32;
368 memcpy(tx,tag.sectors[3],4);
369 }
370 }
371 break;
372
373 // Received RWD authentication challenge and respnse
374 case 64: {
375 // Store the authentication attempt
376 if (auth_table_len < (AUTH_TABLE_LENGTH-8)) {
377 memcpy(auth_table+auth_table_len,rx,8);
378 auth_table_len += 8;
379 }
380
381 // Reset the cipher state
382 hitag2_cipher_reset(&tag,rx);
383 // Check if the authentication was correct
384 if(!hitag2_cipher_authenticate(&(tag.cs),rx+4)) {
385 // The reader failed to authenticate, do nothing
386 Dbprintf("auth: %02x%02x%02x%02x%02x%02x%02x%02x Failed!",rx[0],rx[1],rx[2],rx[3],rx[4],rx[5],rx[6],rx[7]);
387 return;
388 }
389 // Succesful, but commented out reporting back to the Host, this may delay to much.
390 // Dbprintf("auth: %02x%02x%02x%02x%02x%02x%02x%02x OK!",rx[0],rx[1],rx[2],rx[3],rx[4],rx[5],rx[6],rx[7]);
391
392 // Activate encryption algorithm for all further communication
393 tag.crypto_active = 1;
394
395 // Use the tag password as response
396 memcpy(tx,tag.sectors[3],4);
397 *txlen = 32;
398 }
399 break;
400 }
401
402 // LogTrace(rx,nbytes(rxlen),0,0,false);
403 // LogTrace(tx,nbytes(*txlen),0,0,true);
404
405 if(tag.crypto_active) {
406 hitag2_cipher_transcrypt(&(tag.cs), tx, *txlen/8, *txlen%8);
407 }
408 }
409
410 static void hitag_reader_send_bit(int bit) {
411 LED_A_ON();
412 // Reset clock for the next bit
413 AT91C_BASE_TC0->TC_CCR = AT91C_TC_SWTRG;
414
415 // Binary puls length modulation (BPLM) is used to encode the data stream
416 // This means that a transmission of a one takes longer than that of a zero
417
418 // Enable modulation, which means, drop the the field
419 HIGH(GPIO_SSC_DOUT);
420
421 // Wait for 4-10 times the carrier period
422 while(AT91C_BASE_TC0->TC_CV < T0*6);
423 // SpinDelayUs(8*8);
424
425 // Disable modulation, just activates the field again
426 LOW(GPIO_SSC_DOUT);
427
428 if(bit == 0) {
429 // Zero bit: |_-|
430 while(AT91C_BASE_TC0->TC_CV < T0*22);
431 // SpinDelayUs(16*8);
432 } else {
433 // One bit: |_--|
434 while(AT91C_BASE_TC0->TC_CV < T0*28);
435 // SpinDelayUs(22*8);
436 }
437 LED_A_OFF();
438 }
439
440 static void hitag_reader_send_frame(const byte_t* frame, size_t frame_len)
441 {
442 // Send the content of the frame
443 for(size_t i=0; i<frame_len; i++) {
444 hitag_reader_send_bit((frame[i/8] >> (7-(i%8)))&1);
445 }
446 // Send EOF
447 AT91C_BASE_TC0->TC_CCR = AT91C_TC_SWTRG;
448 // Enable modulation, which means, drop the the field
449 HIGH(GPIO_SSC_DOUT);
450 // Wait for 4-10 times the carrier period
451 while(AT91C_BASE_TC0->TC_CV < T0*6);
452 // Disable modulation, just activates the field again
453 LOW(GPIO_SSC_DOUT);
454 }
455
456 size_t blocknr;
457
458 bool hitag2_password(byte_t* rx, const size_t rxlen, byte_t* tx, size_t* txlen) {
459 // Reset the transmission frame length
460 *txlen = 0;
461
462 // Try to find out which command was send by selecting on length (in bits)
463 switch (rxlen) {
464 // No answer, try to resurrect
465 case 0: {
466 // Stop if there is no answer (after sending password)
467 if (bPwd) {
468 DbpString("Password failed!");
469 return false;
470 }
471 *txlen = 5;
472 memcpy(tx,"\xc0",nbytes(*txlen));
473 } break;
474
475 // Received UID, tag password
476 case 32: {
477 if (!bPwd) {
478 *txlen = 32;
479 memcpy(tx,password,4);
480 bPwd = true;
481 memcpy(tag.sectors[blocknr],rx,4);
482 blocknr++;
483 } else {
484
485 if(blocknr == 1){
486 //store password in block1, the TAG answers with Block3, but we need the password in memory
487 memcpy(tag.sectors[blocknr],tx,4);
488 }else{
489 memcpy(tag.sectors[blocknr],rx,4);
490 }
491
492 blocknr++;
493 if (blocknr > 7) {
494 DbpString("Read succesful!");
495 bSuccessful = true;
496 return false;
497 }
498 *txlen = 10;
499 tx[0] = 0xc0 | (blocknr << 3) | ((blocknr^7) >> 2);
500 tx[1] = ((blocknr^7) << 6);
501 }
502 } break;
503
504 // Unexpected response
505 default: {
506 Dbprintf("Uknown frame length: %d",rxlen);
507 return false;
508 } break;
509 }
510 return true;
511 }
512
513 bool hitag2_crypto(byte_t* rx, const size_t rxlen, byte_t* tx, size_t* txlen) {
514 // Reset the transmission frame length
515 *txlen = 0;
516
517 if(bCrypto) {
518 hitag2_cipher_transcrypt(&cipher_state,rx,rxlen/8,rxlen%8);
519 }
520
521 // Try to find out which command was send by selecting on length (in bits)
522 switch (rxlen) {
523 // No answer, try to resurrect
524 case 0: {
525 // Stop if there is no answer while we are in crypto mode (after sending NrAr)
526 if (bCrypto) {
527 // Failed during authentication
528 if (bAuthenticating) {
529 DbpString("Authentication failed!");
530 return false;
531 } else {
532 // Failed reading a block, could be (read/write) locked, skip block and re-authenticate
533 if (blocknr == 1) {
534 // Write the low part of the key in memory
535 memcpy(tag.sectors[1],key+2,4);
536 } else if (blocknr == 2) {
537 // Write the high part of the key in memory
538 tag.sectors[2][0] = 0x00;
539 tag.sectors[2][1] = 0x00;
540 tag.sectors[2][2] = key[0];
541 tag.sectors[2][3] = key[1];
542 } else {
543 // Just put zero's in the memory (of the unreadable block)
544 memset(tag.sectors[blocknr],0x00,4);
545 }
546 blocknr++;
547 bCrypto = false;
548 }
549 } else {
550 *txlen = 5;
551 memcpy(tx,"\xc0",nbytes(*txlen));
552 }
553 } break;
554
555 // Received UID, crypto tag answer
556 case 32: {
557 if (!bCrypto) {
558 uint64_t ui64key = key[0] | ((uint64_t)key[1]) << 8 | ((uint64_t)key[2]) << 16 | ((uint64_t)key[3]) << 24 | ((uint64_t)key[4]) << 32 | ((uint64_t)key[5]) << 40;
559 uint32_t ui32uid = rx[0] | ((uint32_t)rx[1]) << 8 | ((uint32_t)rx[2]) << 16 | ((uint32_t)rx[3]) << 24;
560 cipher_state = _hitag2_init(rev64(ui64key), rev32(ui32uid), 0);
561 memset(tx,0x00,4);
562 memset(tx+4,0xff,4);
563 hitag2_cipher_transcrypt(&cipher_state,tx+4,4,0);
564 *txlen = 64;
565 bCrypto = true;
566 bAuthenticating = true;
567 } else {
568 // Check if we received answer tag (at)
569 if (bAuthenticating) {
570 bAuthenticating = false;
571 } else {
572 // Store the received block
573 memcpy(tag.sectors[blocknr],rx,4);
574 blocknr++;
575 }
576 if (blocknr > 7) {
577 DbpString("Read succesful!");
578 bSuccessful = true;
579 return false;
580 }
581 *txlen = 10;
582 tx[0] = 0xc0 | (blocknr << 3) | ((blocknr^7) >> 2);
583 tx[1] = ((blocknr^7) << 6);
584 }
585 } break;
586
587 // Unexpected response
588 default: {
589 Dbprintf("Uknown frame length: %d",rxlen);
590 return false;
591 } break;
592 }
593
594
595 if(bCrypto) {
596 // We have to return now to avoid double encryption
597 if (!bAuthenticating) {
598 hitag2_cipher_transcrypt(&cipher_state,tx,*txlen/8,*txlen%8);
599 }
600 }
601
602 return true;
603 }
604
605
606 bool hitag2_authenticate(byte_t* rx, const size_t rxlen, byte_t* tx, size_t* txlen) {
607 // Reset the transmission frame length
608 *txlen = 0;
609
610 // Try to find out which command was send by selecting on length (in bits)
611 switch (rxlen) {
612 // No answer, try to resurrect
613 case 0: {
614 // Stop if there is no answer while we are in crypto mode (after sending NrAr)
615 if (bCrypto) {
616 DbpString("Authentication failed!");
617 return false;
618 }
619 *txlen = 5;
620 memcpy(tx,"\xc0",nbytes(*txlen));
621 } break;
622
623 // Received UID, crypto tag answer
624 case 32: {
625 if (!bCrypto) {
626 *txlen = 64;
627 memcpy(tx,NrAr,8);
628 bCrypto = true;
629 } else {
630 DbpString("Authentication succesful!");
631 // We are done... for now
632 return false;
633 }
634 } break;
635
636 // Unexpected response
637 default: {
638 Dbprintf("Uknown frame length: %d",rxlen);
639 return false;
640 } break;
641 }
642
643 return true;
644 }
645
646 bool hitag2_test_auth_attempts(byte_t* rx, const size_t rxlen, byte_t* tx, size_t* txlen) {
647 // Reset the transmission frame length
648 *txlen = 0;
649
650 // Try to find out which command was send by selecting on length (in bits)
651 switch (rxlen) {
652 // No answer, try to resurrect
653 case 0: {
654 // Stop if there is no answer while we are in crypto mode (after sending NrAr)
655 if (bCrypto) {
656 Dbprintf("auth: %02x%02x%02x%02x%02x%02x%02x%02x Failed!",NrAr[0],NrAr[1],NrAr[2],NrAr[3],NrAr[4],NrAr[5],NrAr[6],NrAr[7]);
657 bCrypto = false;
658 if ((auth_table_pos+8) == auth_table_len) {
659 return false;
660 }
661 auth_table_pos += 8;
662 memcpy(NrAr,auth_table+auth_table_pos,8);
663 }
664 *txlen = 5;
665 memcpy(tx,"\xc0",nbytes(*txlen));
666 } break;
667
668 // Received UID, crypto tag answer, or read block response
669 case 32: {
670 if (!bCrypto) {
671 *txlen = 64;
672 memcpy(tx,NrAr,8);
673 bCrypto = true;
674 } else {
675 Dbprintf("auth: %02x%02x%02x%02x%02x%02x%02x%02x OK",NrAr[0],NrAr[1],NrAr[2],NrAr[3],NrAr[4],NrAr[5],NrAr[6],NrAr[7]);
676 bCrypto = false;
677 if ((auth_table_pos+8) == auth_table_len) {
678 return false;
679 }
680 auth_table_pos += 8;
681 memcpy(NrAr,auth_table+auth_table_pos,8);
682 }
683 } break;
684
685 default: {
686 Dbprintf("Uknown frame length: %d",rxlen);
687 return false;
688 } break;
689 }
690
691 return true;
692 }
693
694 void SnoopHitag(uint32_t type) {
695 int frame_count;
696 int response;
697 int overflow;
698 bool rising_edge;
699 bool reader_frame;
700 int lastbit;
701 bool bSkip;
702 int tag_sof;
703 byte_t rx[HITAG_FRAME_LEN];
704 size_t rxlen=0;
705
706 // Clean up trace and prepare it for storing frames
707 iso14a_set_tracing(TRUE);
708 iso14a_clear_trace();
709
710 auth_table_len = 0;
711 auth_table_pos = 0;
712 memset(auth_table, 0x00, AUTH_TABLE_LENGTH);
713
714 DbpString("Starting Hitag2 snoop");
715 LED_D_ON();
716
717 // Set up eavesdropping mode, frequency divisor which will drive the FPGA
718 // and analog mux selection.
719 FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_EDGE_DETECT);
720 FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
721 SetAdcMuxFor(GPIO_MUXSEL_LOPKD);
722 RELAY_OFF();
723
724 // Configure output pin that is connected to the FPGA (for modulating)
725 AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
726 AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT;
727
728 // Disable modulation, we are going to eavesdrop, not modulate ;)
729 LOW(GPIO_SSC_DOUT);
730
731 // Enable Peripheral Clock for TIMER_CLOCK1, used to capture edges of the reader frames
732 AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC1);
733 AT91C_BASE_PIOA->PIO_BSR = GPIO_SSC_FRAME;
734
735 // Disable timer during configuration
736 AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
737
738 // Capture mode, defaul timer source = MCK/2 (TIMER_CLOCK1), TIOA is external trigger,
739 // external trigger rising edge, load RA on rising edge of TIOA.
740 uint32_t t1_channel_mode = AT91C_TC_CLKS_TIMER_DIV1_CLOCK | AT91C_TC_ETRGEDG_BOTH | AT91C_TC_ABETRG | AT91C_TC_LDRA_BOTH;
741 AT91C_BASE_TC1->TC_CMR = t1_channel_mode;
742
743 // Enable and reset counter
744 AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
745
746 // Reset the received frame, frame count and timing info
747 memset(rx,0x00,sizeof(rx));
748 frame_count = 0;
749 response = 0;
750 overflow = 0;
751 reader_frame = false;
752 lastbit = 1;
753 bSkip = true;
754 tag_sof = 4;
755
756 while(!BUTTON_PRESS()) {
757 // Watchdog hit
758 WDT_HIT();
759
760 // Receive frame, watch for at most T0*EOF periods
761 while (AT91C_BASE_TC1->TC_CV < T0*HITAG_T_EOF) {
762 // Check if rising edge in modulation is detected
763 if(AT91C_BASE_TC1->TC_SR & AT91C_TC_LDRAS) {
764 // Retrieve the new timing values
765 int ra = (AT91C_BASE_TC1->TC_RA/T0);
766
767 // Find out if we are dealing with a rising or falling edge
768 rising_edge = (AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_FRAME) > 0;
769
770 // Shorter periods will only happen with reader frames
771 if (!reader_frame && rising_edge && ra < HITAG_T_TAG_CAPTURE_ONE_HALF) {
772 // Switch from tag to reader capture
773 LED_C_OFF();
774 reader_frame = true;
775 memset(rx,0x00,sizeof(rx));
776 rxlen = 0;
777 }
778
779 // Only handle if reader frame and rising edge, or tag frame and falling edge
780 if (reader_frame != rising_edge) {
781 overflow += ra;
782 continue;
783 }
784
785 // Add the buffered timing values of earlier captured edges which were skipped
786 ra += overflow;
787 overflow = 0;
788
789 if (reader_frame) {
790 LED_B_ON();
791 // Capture reader frame
792 if(ra >= HITAG_T_STOP) {
793 if (rxlen != 0) {
794 //DbpString("wierd0?");
795 }
796 // Capture the T0 periods that have passed since last communication or field drop (reset)
797 response = (ra - HITAG_T_LOW);
798 } else if(ra >= HITAG_T_1_MIN ) {
799 // '1' bit
800 rx[rxlen / 8] |= 1 << (7-(rxlen%8));
801 rxlen++;
802 } else if(ra >= HITAG_T_0_MIN) {
803 // '0' bit
804 rx[rxlen / 8] |= 0 << (7-(rxlen%8));
805 rxlen++;
806 } else {
807 // Ignore wierd value, is to small to mean anything
808 }
809 } else {
810 LED_C_ON();
811 // Capture tag frame (manchester decoding using only falling edges)
812 if(ra >= HITAG_T_EOF) {
813 if (rxlen != 0) {
814 //DbpString("wierd1?");
815 }
816 // Capture the T0 periods that have passed since last communication or field drop (reset)
817 // We always recieve a 'one' first, which has the falling edge after a half period |-_|
818 response = ra-HITAG_T_TAG_HALF_PERIOD;
819 } else if(ra >= HITAG_T_TAG_CAPTURE_FOUR_HALF) {
820 // Manchester coding example |-_|_-|-_| (101)
821 rx[rxlen / 8] |= 0 << (7-(rxlen%8));
822 rxlen++;
823 rx[rxlen / 8] |= 1 << (7-(rxlen%8));
824 rxlen++;
825 } else if(ra >= HITAG_T_TAG_CAPTURE_THREE_HALF) {
826 // Manchester coding example |_-|...|_-|-_| (0...01)
827 rx[rxlen / 8] |= 0 << (7-(rxlen%8));
828 rxlen++;
829 // We have to skip this half period at start and add the 'one' the second time
830 if (!bSkip) {
831 rx[rxlen / 8] |= 1 << (7-(rxlen%8));
832 rxlen++;
833 }
834 lastbit = !lastbit;
835 bSkip = !bSkip;
836 } else if(ra >= HITAG_T_TAG_CAPTURE_TWO_HALF) {
837 // Manchester coding example |_-|_-| (00) or |-_|-_| (11)
838 if (tag_sof) {
839 // Ignore bits that are transmitted during SOF
840 tag_sof--;
841 } else {
842 // bit is same as last bit
843 rx[rxlen / 8] |= lastbit << (7-(rxlen%8));
844 rxlen++;
845 }
846 } else {
847 // Ignore wierd value, is to small to mean anything
848 }
849 }
850 }
851 }
852
853 // Check if frame was captured
854 if(rxlen > 0) {
855 frame_count++;
856 if (!LogTrace(rx,nbytes(rxlen),response,0,reader_frame)) {
857 DbpString("Trace full");
858 break;
859 }
860
861 // Check if we recognize a valid authentication attempt
862 if (nbytes(rxlen) == 8) {
863 // Store the authentication attempt
864 if (auth_table_len < (AUTH_TABLE_LENGTH-8)) {
865 memcpy(auth_table+auth_table_len,rx,8);
866 auth_table_len += 8;
867 }
868 }
869
870 // Reset the received frame and response timing info
871 memset(rx,0x00,sizeof(rx));
872 response = 0;
873 reader_frame = false;
874 lastbit = 1;
875 bSkip = true;
876 tag_sof = 4;
877 overflow = 0;
878
879 LED_B_OFF();
880 LED_C_OFF();
881 } else {
882 // Save the timer overflow, will be 0 when frame was received
883 overflow += (AT91C_BASE_TC1->TC_CV/T0);
884 }
885 // Reset the frame length
886 rxlen = 0;
887 // Reset the timer to restart while-loop that receives frames
888 AT91C_BASE_TC1->TC_CCR = AT91C_TC_SWTRG;
889 }
890 LED_A_ON();
891 LED_B_OFF();
892 LED_C_OFF();
893 LED_D_OFF();
894 AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
895 AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS;
896 FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
897 LED_A_OFF();
898
899 // Dbprintf("frame received: %d",frame_count);
900 // Dbprintf("Authentication Attempts: %d",(auth_table_len/8));
901 // DbpString("All done");
902 }
903
904 void SimulateHitagTag(bool tag_mem_supplied, byte_t* data) {
905 int frame_count;
906 int response;
907 int overflow;
908 byte_t rx[HITAG_FRAME_LEN];
909 size_t rxlen=0;
910 byte_t tx[HITAG_FRAME_LEN];
911 size_t txlen=0;
912 bool bQuitTraceFull = false;
913 bQuiet = false;
914
915 // Clean up trace and prepare it for storing frames
916 iso14a_set_tracing(TRUE);
917 iso14a_clear_trace();
918 auth_table_len = 0;
919 auth_table_pos = 0;
920 memset(auth_table, 0x00, AUTH_TABLE_LENGTH);
921
922 DbpString("Starting Hitag2 simulation");
923 LED_D_ON();
924 hitag2_init();
925
926 if (tag_mem_supplied) {
927 DbpString("Loading hitag2 memory...");
928 memcpy((byte_t*)tag.sectors,data,48);
929 }
930
931 uint32_t block = 0;
932 for (size_t i=0; i<12; i++) {
933 for (size_t j=0; j<4; j++) {
934 block <<= 8;
935 block |= tag.sectors[i][j];
936 }
937 Dbprintf("| %d | %08x |",i,block);
938 }
939
940 // Set up simulator mode, frequency divisor which will drive the FPGA
941 // and analog mux selection.
942 FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_EDGE_DETECT);
943 FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
944 SetAdcMuxFor(GPIO_MUXSEL_LOPKD);
945 RELAY_OFF();
946
947 // Configure output pin that is connected to the FPGA (for modulating)
948 AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
949 AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT;
950
951 // Disable modulation at default, which means release resistance
952 LOW(GPIO_SSC_DOUT);
953
954 // Enable Peripheral Clock for TIMER_CLOCK0, used to measure exact timing before answering
955 AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC0);
956
957 // Enable Peripheral Clock for TIMER_CLOCK1, used to capture edges of the reader frames
958 AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC1);
959 AT91C_BASE_PIOA->PIO_BSR = GPIO_SSC_FRAME;
960
961 // Disable timer during configuration
962 AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
963
964 // Capture mode, defaul timer source = MCK/2 (TIMER_CLOCK1), TIOA is external trigger,
965 // external trigger rising edge, load RA on rising edge of TIOA.
966 AT91C_BASE_TC1->TC_CMR = AT91C_TC_CLKS_TIMER_DIV1_CLOCK | AT91C_TC_ETRGEDG_RISING | AT91C_TC_ABETRG | AT91C_TC_LDRA_RISING;
967
968 // Enable and reset counter
969 AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
970
971 // Reset the received frame, frame count and timing info
972 memset(rx,0x00,sizeof(rx));
973 frame_count = 0;
974 response = 0;
975 overflow = 0;
976
977 while(!BUTTON_PRESS()) {
978 // Watchdog hit
979 WDT_HIT();
980
981 // Receive frame, watch for at most T0*EOF periods
982 while (AT91C_BASE_TC1->TC_CV < T0*HITAG_T_EOF) {
983 // Check if rising edge in modulation is detected
984 if(AT91C_BASE_TC1->TC_SR & AT91C_TC_LDRAS) {
985 // Retrieve the new timing values
986 int ra = (AT91C_BASE_TC1->TC_RA/T0) + overflow;
987 overflow = 0;
988
989 // Reset timer every frame, we have to capture the last edge for timing
990 AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
991
992 LED_B_ON();
993
994 // Capture reader frame
995 if(ra >= HITAG_T_STOP) {
996 if (rxlen != 0) {
997 //DbpString("wierd0?");
998 }
999 // Capture the T0 periods that have passed since last communication or field drop (reset)
1000 response = (ra - HITAG_T_LOW);
1001 } else if(ra >= HITAG_T_1_MIN ) {
1002 // '1' bit
1003 rx[rxlen / 8] |= 1 << (7-(rxlen%8));
1004 rxlen++;
1005 } else if(ra >= HITAG_T_0_MIN) {
1006 // '0' bit
1007 rx[rxlen / 8] |= 0 << (7-(rxlen%8));
1008 rxlen++;
1009 } else {
1010 // Ignore wierd value, is to small to mean anything
1011 }
1012 }
1013 }
1014
1015 // Check if frame was captured
1016 if(rxlen > 4) {
1017 frame_count++;
1018 if (!bQuiet) {
1019 if (!LogTrace(rx,nbytes(rxlen),response,0,true)) {
1020 DbpString("Trace full");
1021 if (bQuitTraceFull) {
1022 break;
1023 } else {
1024 bQuiet = true;
1025 }
1026 }
1027 }
1028
1029 // Disable timer 1 with external trigger to avoid triggers during our own modulation
1030 AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
1031
1032 // Process the incoming frame (rx) and prepare the outgoing frame (tx)
1033 hitag2_handle_reader_command(rx,rxlen,tx,&txlen);
1034
1035 // Wait for HITAG_T_WAIT_1 carrier periods after the last reader bit,
1036 // not that since the clock counts since the rising edge, but T_Wait1 is
1037 // with respect to the falling edge, we need to wait actually (T_Wait1 - T_Low)
1038 // periods. The gap time T_Low varies (4..10). All timer values are in
1039 // terms of T0 units
1040 while(AT91C_BASE_TC0->TC_CV < T0*(HITAG_T_WAIT_1-HITAG_T_LOW));
1041
1042 // Send and store the tag answer (if there is any)
1043 if (txlen) {
1044 // Transmit the tag frame
1045 hitag_send_frame(tx,txlen);
1046 // Store the frame in the trace
1047 if (!bQuiet) {
1048 if (!LogTrace(tx,nbytes(txlen),0,0,false)) {
1049 DbpString("Trace full");
1050 if (bQuitTraceFull) {
1051 break;
1052 } else {
1053 bQuiet = true;
1054 }
1055 }
1056 }
1057 }
1058
1059 // Reset the received frame and response timing info
1060 memset(rx,0x00,sizeof(rx));
1061 response = 0;
1062
1063 // Enable and reset external trigger in timer for capturing future frames
1064 AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
1065 LED_B_OFF();
1066 }
1067 // Reset the frame length
1068 rxlen = 0;
1069 // Save the timer overflow, will be 0 when frame was received
1070 overflow += (AT91C_BASE_TC1->TC_CV/T0);
1071 // Reset the timer to restart while-loop that receives frames
1072 AT91C_BASE_TC1->TC_CCR = AT91C_TC_SWTRG;
1073 }
1074 LED_B_OFF();
1075 LED_D_OFF();
1076 AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
1077 AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS;
1078 FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
1079 // Dbprintf("frame received: %d",frame_count);
1080 // Dbprintf("Authentication Attempts: %d",(auth_table_len/8));
1081 // DbpString("All done");
1082 }
1083
1084 void ReaderHitag(hitag_function htf, hitag_data* htd) {
1085 int frame_count;
1086 int response;
1087 byte_t rx[HITAG_FRAME_LEN];
1088 size_t rxlen=0;
1089 byte_t txbuf[HITAG_FRAME_LEN];
1090 byte_t* tx = txbuf;
1091 size_t txlen=0;
1092 int lastbit;
1093 bool bSkip;
1094 int reset_sof;
1095 int tag_sof;
1096 int t_wait = HITAG_T_WAIT_MAX;
1097 bool bStop;
1098 bool bQuitTraceFull = false;
1099
1100 // Reset the return status
1101 bSuccessful = false;
1102
1103 // Clean up trace and prepare it for storing frames
1104 iso14a_set_tracing(TRUE);
1105 iso14a_clear_trace();
1106 DbpString("Starting Hitag reader family");
1107
1108 // Check configuration
1109 switch(htf) {
1110 case RHT2F_PASSWORD: {
1111 Dbprintf("List identifier in password mode");
1112 memcpy(password,htd->pwd.password,4);
1113 blocknr = 0;
1114 bQuitTraceFull = false;
1115 bQuiet = false;
1116 bPwd = false;
1117 } break;
1118
1119 case RHT2F_AUTHENTICATE: {
1120 DbpString("Authenticating using nr,ar pair:");
1121 memcpy(NrAr,htd->auth.NrAr,8);
1122 Dbhexdump(8,NrAr,false);
1123 bQuiet = false;
1124 bCrypto = false;
1125 bAuthenticating = false;
1126 bQuitTraceFull = true;
1127 } break;
1128
1129 case RHT2F_CRYPTO: {
1130 DbpString("Authenticating using key:");
1131 memcpy(key,htd->crypto.key,6);
1132 Dbhexdump(6,key,false);
1133 blocknr = 0;
1134 bQuiet = false;
1135 bCrypto = false;
1136 bAuthenticating = false;
1137 bQuitTraceFull = true;
1138 } break;
1139
1140 case RHT2F_TEST_AUTH_ATTEMPTS: {
1141 Dbprintf("Testing %d authentication attempts",(auth_table_len/8));
1142 auth_table_pos = 0;
1143 memcpy(NrAr,auth_table,8);
1144 bQuitTraceFull = false;
1145 bQuiet = false;
1146 bCrypto = false;
1147 } break;
1148
1149 default: {
1150 Dbprintf("Error, unknown function: %d",htf);
1151 return;
1152 } break;
1153 }
1154
1155 LED_D_ON();
1156 hitag2_init();
1157
1158 // Configure output and enable pin that is connected to the FPGA (for modulating)
1159 AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
1160 AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT;
1161
1162 // Set fpga in edge detect with reader field, we can modulate as reader now
1163 FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_EDGE_DETECT | FPGA_LF_EDGE_DETECT_READER_FIELD);
1164
1165 // Set Frequency divisor which will drive the FPGA and analog mux selection
1166 FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
1167 SetAdcMuxFor(GPIO_MUXSEL_LOPKD);
1168 RELAY_OFF();
1169
1170 // Disable modulation at default, which means enable the field
1171 LOW(GPIO_SSC_DOUT);
1172
1173 // Give it a bit of time for the resonant antenna to settle.
1174 SpinDelay(30);
1175
1176 // Enable Peripheral Clock for TIMER_CLOCK0, used to measure exact timing before answering
1177 AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC0);
1178
1179 // Enable Peripheral Clock for TIMER_CLOCK1, used to capture edges of the tag frames
1180 AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC1);
1181 AT91C_BASE_PIOA->PIO_BSR = GPIO_SSC_FRAME;
1182
1183 // Disable timer during configuration
1184 AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
1185
1186 // Capture mode, defaul timer source = MCK/2 (TIMER_CLOCK1), TIOA is external trigger,
1187 // external trigger rising edge, load RA on falling edge of TIOA.
1188 AT91C_BASE_TC1->TC_CMR = AT91C_TC_CLKS_TIMER_DIV1_CLOCK | AT91C_TC_ETRGEDG_FALLING | AT91C_TC_ABETRG | AT91C_TC_LDRA_FALLING;
1189
1190 // Enable and reset counters
1191 AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
1192 AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
1193
1194 // Reset the received frame, frame count and timing info
1195 frame_count = 0;
1196 response = 0;
1197 lastbit = 1;
1198 bStop = false;
1199
1200 // Tag specific configuration settings (sof, timings, etc.)
1201 if (htf < 10){
1202 // hitagS settings
1203 reset_sof = 1;
1204 t_wait = 200;
1205 DbpString("Configured for hitagS reader");
1206 } else if (htf < 20) {
1207 // hitag1 settings
1208 reset_sof = 1;
1209 t_wait = 200;
1210 DbpString("Configured for hitag1 reader");
1211 } else if (htf < 30) {
1212 // hitag2 settings
1213 reset_sof = 4;
1214 t_wait = HITAG_T_WAIT_2;
1215 DbpString("Configured for hitag2 reader");
1216 } else {
1217 Dbprintf("Error, unknown hitag reader type: %d",htf);
1218 return;
1219 }
1220
1221 while(!bStop && !BUTTON_PRESS()) {
1222 // Watchdog hit
1223 WDT_HIT();
1224
1225 // Check if frame was captured and store it
1226 if(rxlen > 0) {
1227 frame_count++;
1228 if (!bQuiet) {
1229 if (!LogTrace(rx,nbytes(rxlen),response,0,false)) {
1230 DbpString("Trace full");
1231 if (bQuitTraceFull) {
1232 break;
1233 } else {
1234 bQuiet = true;
1235 }
1236 }
1237 }
1238 }
1239
1240 // By default reset the transmission buffer
1241 tx = txbuf;
1242 switch(htf) {
1243 case RHT2F_PASSWORD: {
1244 bStop = !hitag2_password(rx,rxlen,tx,&txlen);
1245 } break;
1246 case RHT2F_AUTHENTICATE: {
1247 bStop = !hitag2_authenticate(rx,rxlen,tx,&txlen);
1248 } break;
1249 case RHT2F_CRYPTO: {
1250 bStop = !hitag2_crypto(rx,rxlen,tx,&txlen);
1251 } break;
1252 case RHT2F_TEST_AUTH_ATTEMPTS: {
1253 bStop = !hitag2_test_auth_attempts(rx,rxlen,tx,&txlen);
1254 } break;
1255 default: {
1256 Dbprintf("Error, unknown function: %d",htf);
1257 return;
1258 } break;
1259 }
1260
1261 // Send and store the reader command
1262 // Disable timer 1 with external trigger to avoid triggers during our own modulation
1263 AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
1264
1265 // Wait for HITAG_T_WAIT_2 carrier periods after the last tag bit before transmitting,
1266 // Since the clock counts since the last falling edge, a 'one' means that the
1267 // falling edge occured halfway the period. with respect to this falling edge,
1268 // we need to wait (T_Wait2 + half_tag_period) when the last was a 'one'.
1269 // All timer values are in terms of T0 units
1270 while(AT91C_BASE_TC0->TC_CV < T0*(t_wait+(HITAG_T_TAG_HALF_PERIOD*lastbit)));
1271
1272 // Transmit the reader frame
1273 hitag_reader_send_frame(tx,txlen);
1274
1275 // Enable and reset external trigger in timer for capturing future frames
1276 AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
1277
1278 // Add transmitted frame to total count
1279 if(txlen > 0) {
1280 frame_count++;
1281 if (!bQuiet) {
1282 // Store the frame in the trace
1283 if (!LogTrace(tx,nbytes(txlen),HITAG_T_WAIT_2,0,true)) {
1284 if (bQuitTraceFull) {
1285 break;
1286 } else {
1287 bQuiet = true;
1288 }
1289 }
1290 }
1291 }
1292
1293 // Reset values for receiving frames
1294 memset(rx,0x00,sizeof(rx));
1295 rxlen = 0;
1296 lastbit = 1;
1297 bSkip = true;
1298 tag_sof = reset_sof;
1299 response = 0;
1300
1301 // Receive frame, watch for at most T0*EOF periods
1302 while (AT91C_BASE_TC1->TC_CV < T0*HITAG_T_WAIT_MAX) {
1303 // Check if falling edge in tag modulation is detected
1304 if(AT91C_BASE_TC1->TC_SR & AT91C_TC_LDRAS) {
1305 // Retrieve the new timing values
1306 int ra = (AT91C_BASE_TC1->TC_RA/T0);
1307
1308 // Reset timer every frame, we have to capture the last edge for timing
1309 AT91C_BASE_TC0->TC_CCR = AT91C_TC_SWTRG;
1310
1311 LED_B_ON();
1312
1313 // Capture tag frame (manchester decoding using only falling edges)
1314 if(ra >= HITAG_T_EOF) {
1315 if (rxlen != 0) {
1316 //DbpString("wierd1?");
1317 }
1318 // Capture the T0 periods that have passed since last communication or field drop (reset)
1319 // We always recieve a 'one' first, which has the falling edge after a half period |-_|
1320 response = ra-HITAG_T_TAG_HALF_PERIOD;
1321 } else if(ra >= HITAG_T_TAG_CAPTURE_FOUR_HALF) {
1322 // Manchester coding example |-_|_-|-_| (101)
1323 rx[rxlen / 8] |= 0 << (7-(rxlen%8));
1324 rxlen++;
1325 rx[rxlen / 8] |= 1 << (7-(rxlen%8));
1326 rxlen++;
1327 } else if(ra >= HITAG_T_TAG_CAPTURE_THREE_HALF) {
1328 // Manchester coding example |_-|...|_-|-_| (0...01)
1329 rx[rxlen / 8] |= 0 << (7-(rxlen%8));
1330 rxlen++;
1331 // We have to skip this half period at start and add the 'one' the second time
1332 if (!bSkip) {
1333 rx[rxlen / 8] |= 1 << (7-(rxlen%8));
1334 rxlen++;
1335 }
1336 lastbit = !lastbit;
1337 bSkip = !bSkip;
1338 } else if(ra >= HITAG_T_TAG_CAPTURE_TWO_HALF) {
1339 // Manchester coding example |_-|_-| (00) or |-_|-_| (11)
1340 if (tag_sof) {
1341 // Ignore bits that are transmitted during SOF
1342 tag_sof--;
1343 } else {
1344 // bit is same as last bit
1345 rx[rxlen / 8] |= lastbit << (7-(rxlen%8));
1346 rxlen++;
1347 }
1348 } else {
1349 // Ignore wierd value, is to small to mean anything
1350 }
1351 }
1352
1353 // We can break this loop if we received the last bit from a frame
1354 if (AT91C_BASE_TC1->TC_CV > T0*HITAG_T_EOF) {
1355 if (rxlen>0) break;
1356 }
1357 }
1358 }
1359 LED_B_OFF();
1360 LED_D_OFF();
1361 AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
1362 AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS;
1363 FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
1364 Dbprintf("frame received: %d",frame_count);
1365 DbpString("All done");
1366 cmd_send(CMD_ACK,bSuccessful,0,0,(byte_t*)tag.sectors,48);
1367 }
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