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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
33 int LogTraceHitag(const uint8_t * btBytes, int iBits, int iSamples, uint32_t dwParity, int bReader)
34 {
35 static uint16_t traceLen = 0;
36 uint8_t *trace = BigBuf_get_addr();
37
38 // Return when trace is full
39 if (traceLen >= TRACE_SIZE) return FALSE;
40
41 // Trace the random, i'm curious
42 rsamples += iSamples;
43 trace[traceLen++] = ((rsamples >> 0) & 0xff);
44 trace[traceLen++] = ((rsamples >> 8) & 0xff);
45 trace[traceLen++] = ((rsamples >> 16) & 0xff);
46 trace[traceLen++] = ((rsamples >> 24) & 0xff);
47 if (!bReader) {
48 trace[traceLen - 1] |= 0x80;
49 }
50 trace[traceLen++] = ((dwParity >> 0) & 0xff);
51 trace[traceLen++] = ((dwParity >> 8) & 0xff);
52 trace[traceLen++] = ((dwParity >> 16) & 0xff);
53 trace[traceLen++] = ((dwParity >> 24) & 0xff);
54 trace[traceLen++] = iBits;
55 memcpy(trace + traceLen, btBytes, nbytes(iBits));
56 traceLen += nbytes(iBits);
57 return TRUE;
58 }
59
60 struct hitag2_tag {
61 uint32_t uid;
62 enum {
63 TAG_STATE_RESET = 0x01, // Just powered up, awaiting GetSnr
64 TAG_STATE_ACTIVATING = 0x02 , // In activation phase (password mode), sent UID, awaiting reader password
65 TAG_STATE_ACTIVATED = 0x03, // Activation complete, awaiting read/write commands
66 TAG_STATE_WRITING = 0x04, // In write command, awaiting sector contents to be written
67 } state;
68 unsigned int active_sector;
69 byte_t crypto_active;
70 uint64_t cs;
71 byte_t sectors[12][4];
72 };
73
74 static struct hitag2_tag tag = {
75 .state = TAG_STATE_RESET,
76 .sectors = { // Password mode: | Crypto mode:
77 [0] = { 0x02, 0x4e, 0x02, 0x20}, // UID | UID
78 [1] = { 0x4d, 0x49, 0x4b, 0x52}, // Password RWD | 32 bit LSB key
79 [2] = { 0x20, 0xf0, 0x4f, 0x4e}, // Reserved | 16 bit MSB key, 16 bit reserved
80 [3] = { 0x0e, 0xaa, 0x48, 0x54}, // Configuration, password TAG | Configuration, password TAG
81 [4] = { 0x46, 0x5f, 0x4f, 0x4b}, // Data: F_OK
82 [5] = { 0x55, 0x55, 0x55, 0x55}, // Data: UUUU
83 [6] = { 0xaa, 0xaa, 0xaa, 0xaa}, // Data: ....
84 [7] = { 0x55, 0x55, 0x55, 0x55}, // Data: UUUU
85 [8] = { 0x00, 0x00, 0x00, 0x00}, // RSK Low
86 [9] = { 0x00, 0x00, 0x00, 0x00}, // RSK High
87 [10] = { 0x00, 0x00, 0x00, 0x00}, // RCF
88 [11] = { 0x00, 0x00, 0x00, 0x00}, // SYNC
89 },
90 };
91
92 //#define TRACE_LENGTH 3000
93 //uint8_t *trace = (uint8_t *) BigBuf;
94 //int traceLen = 0;
95 //int rsamples = 0;
96
97 #define AUTH_TABLE_OFFSET FREE_BUFFER_OFFSET
98 #define AUTH_TABLE_LENGTH FREE_BUFFER_SIZE
99 size_t auth_table_pos = 0;
100 size_t auth_table_len = AUTH_TABLE_LENGTH;
101
102 byte_t password[4];
103 byte_t NrAr[8];
104 byte_t key[8];
105 uint64_t cipher_state;
106
107 /* Following is a modified version of cryptolib.com/ciphers/hitag2/ */
108 // Software optimized 48-bit Philips/NXP Mifare Hitag2 PCF7936/46/47/52 stream cipher algorithm by I.C. Wiener 2006-2007.
109 // For educational purposes only.
110 // No warranties or guarantees of any kind.
111 // This code is released into the public domain by its author.
112
113 // Basic macros:
114
115 #define u8 uint8_t
116 #define u32 uint32_t
117 #define u64 uint64_t
118 #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))
119 #define rev16(x) (rev8 (x)+(rev8 (x>> 8)<< 8))
120 #define rev32(x) (rev16(x)+(rev16(x>>16)<<16))
121 #define rev64(x) (rev32(x)+(rev32(x>>32)<<32))
122 #define bit(x,n) (((x)>>(n))&1)
123 #define bit32(x,n) ((((x)[(n)>>5])>>((n)))&1)
124 #define inv32(x,i,n) ((x)[(i)>>5]^=((u32)(n))<<((i)&31))
125 #define rotl64(x, n) ((((u64)(x))<<((n)&63))+(((u64)(x))>>((0-(n))&63)))
126
127 // Single bit Hitag2 functions:
128
129 #define i4(x,a,b,c,d) ((u32)((((x)>>(a))&1)+(((x)>>(b))&1)*2+(((x)>>(c))&1)*4+(((x)>>(d))&1)*8))
130
131 static const u32 ht2_f4a = 0x2C79; // 0010 1100 0111 1001
132 static const u32 ht2_f4b = 0x6671; // 0110 0110 0111 0001
133 static const u32 ht2_f5c = 0x7907287B; // 0111 1001 0000 0111 0010 1000 0111 1011
134
135 static u32 _f20 (const u64 x)
136 {
137 u32 i5;
138
139 i5 = ((ht2_f4a >> i4 (x, 1, 2, 4, 5)) & 1)* 1
140 + ((ht2_f4b >> i4 (x, 7,11,13,14)) & 1)* 2
141 + ((ht2_f4b >> i4 (x,16,20,22,25)) & 1)* 4
142 + ((ht2_f4b >> i4 (x,27,28,30,32)) & 1)* 8
143 + ((ht2_f4a >> i4 (x,33,42,43,45)) & 1)*16;
144
145 return (ht2_f5c >> i5) & 1;
146 }
147
148 static u64 _hitag2_init (const u64 key, const u32 serial, const u32 IV)
149 {
150 u32 i;
151 u64 x = ((key & 0xFFFF) << 32) + serial;
152
153 for (i = 0; i < 32; i++)
154 {
155 x >>= 1;
156 x += (u64) (_f20 (x) ^ (((IV >> i) ^ (key >> (i+16))) & 1)) << 47;
157 }
158 return x;
159 }
160
161 static u64 _hitag2_round (u64 *state)
162 {
163 u64 x = *state;
164
165 x = (x >> 1) +
166 ((((x >> 0) ^ (x >> 2) ^ (x >> 3) ^ (x >> 6)
167 ^ (x >> 7) ^ (x >> 8) ^ (x >> 16) ^ (x >> 22)
168 ^ (x >> 23) ^ (x >> 26) ^ (x >> 30) ^ (x >> 41)
169 ^ (x >> 42) ^ (x >> 43) ^ (x >> 46) ^ (x >> 47)) & 1) << 47);
170
171 *state = x;
172 return _f20 (x);
173 }
174
175 static u32 _hitag2_byte (u64 * x)
176 {
177 u32 i, c;
178
179 for (i = 0, c = 0; i < 8; i++) c += (u32) _hitag2_round (x) << (i^7);
180 return c;
181 }
182
183 int hitag2_reset(void)
184 {
185 tag.state = TAG_STATE_RESET;
186 tag.crypto_active = 0;
187 return 0;
188 }
189
190 int hitag2_init(void)
191 {
192 // memcpy(&tag, &resetdata, sizeof(tag));
193 hitag2_reset();
194 return 0;
195 }
196
197 static void hitag2_cipher_reset(struct hitag2_tag *tag, const byte_t *iv)
198 {
199 uint64_t key = ((uint64_t)tag->sectors[2][2]) |
200 ((uint64_t)tag->sectors[2][3] << 8) |
201 ((uint64_t)tag->sectors[1][0] << 16) |
202 ((uint64_t)tag->sectors[1][1] << 24) |
203 ((uint64_t)tag->sectors[1][2] << 32) |
204 ((uint64_t)tag->sectors[1][3] << 40);
205 uint32_t uid = ((uint32_t)tag->sectors[0][0]) |
206 ((uint32_t)tag->sectors[0][1] << 8) |
207 ((uint32_t)tag->sectors[0][2] << 16) |
208 ((uint32_t)tag->sectors[0][3] << 24);
209 uint32_t iv_ = (((uint32_t)(iv[0]))) |
210 (((uint32_t)(iv[1])) << 8) |
211 (((uint32_t)(iv[2])) << 16) |
212 (((uint32_t)(iv[3])) << 24);
213 tag->cs = _hitag2_init(rev64(key), rev32(uid), rev32(iv_));
214 }
215
216 static int hitag2_cipher_authenticate(uint64_t* cs, const byte_t *authenticator_is)
217 {
218 byte_t authenticator_should[4];
219 authenticator_should[0] = ~_hitag2_byte(cs);
220 authenticator_should[1] = ~_hitag2_byte(cs);
221 authenticator_should[2] = ~_hitag2_byte(cs);
222 authenticator_should[3] = ~_hitag2_byte(cs);
223 return (memcmp(authenticator_should, authenticator_is, 4) == 0);
224 }
225
226 static int hitag2_cipher_transcrypt(uint64_t* cs, byte_t *data, unsigned int bytes, unsigned int bits)
227 {
228 int i;
229 for(i=0; i<bytes; i++) data[i] ^= _hitag2_byte(cs);
230 for(i=0; i<bits; i++) data[bytes] ^= _hitag2_round(cs) << (7-i);
231 return 0;
232 }
233
234 // Sam7s has several timers, we will use the source TIMER_CLOCK1 (aka AT91C_TC_CLKS_TIMER_DIV1_CLOCK)
235 // TIMER_CLOCK1 = MCK/2, MCK is running at 48 MHz, Timer is running at 48/2 = 24 MHz
236 // Hitag units (T0) have duration of 8 microseconds (us), which is 1/125000 per second (carrier)
237 // T0 = TIMER_CLOCK1 / 125000 = 192
238 #define T0 192
239
240 #define SHORT_COIL() LOW(GPIO_SSC_DOUT)
241 #define OPEN_COIL() HIGH(GPIO_SSC_DOUT)
242
243 #define HITAG_FRAME_LEN 20
244 #define HITAG_T_STOP 36 /* T_EOF should be > 36 */
245 #define HITAG_T_LOW 8 /* T_LOW should be 4..10 */
246 #define HITAG_T_0_MIN 15 /* T[0] should be 18..22 */
247 #define HITAG_T_1_MIN 25 /* T[1] should be 26..30 */
248 //#define HITAG_T_EOF 40 /* T_EOF should be > 36 */
249 #define HITAG_T_EOF 80 /* T_EOF should be > 36 */
250 #define HITAG_T_WAIT_1 200 /* T_wresp should be 199..206 */
251 #define HITAG_T_WAIT_2 90 /* T_wresp should be 199..206 */
252 #define HITAG_T_WAIT_MAX 300 /* bit more than HITAG_T_WAIT_1 + HITAG_T_WAIT_2 */
253
254 #define HITAG_T_TAG_ONE_HALF_PERIOD 10
255 #define HITAG_T_TAG_TWO_HALF_PERIOD 25
256 #define HITAG_T_TAG_THREE_HALF_PERIOD 41
257 #define HITAG_T_TAG_FOUR_HALF_PERIOD 57
258
259 #define HITAG_T_TAG_HALF_PERIOD 16
260 #define HITAG_T_TAG_FULL_PERIOD 32
261
262 #define HITAG_T_TAG_CAPTURE_ONE_HALF 13
263 #define HITAG_T_TAG_CAPTURE_TWO_HALF 25
264 #define HITAG_T_TAG_CAPTURE_THREE_HALF 41
265 #define HITAG_T_TAG_CAPTURE_FOUR_HALF 57
266
267
268 static void hitag_send_bit(int bit) {
269 LED_A_ON();
270 // Reset clock for the next bit
271 AT91C_BASE_TC0->TC_CCR = AT91C_TC_SWTRG;
272
273 // Fixed modulation, earlier proxmark version used inverted signal
274 if(bit == 0) {
275 // Manchester: Unloaded, then loaded |__--|
276 LOW(GPIO_SSC_DOUT);
277 while(AT91C_BASE_TC0->TC_CV < T0*HITAG_T_TAG_HALF_PERIOD);
278 HIGH(GPIO_SSC_DOUT);
279 while(AT91C_BASE_TC0->TC_CV < T0*HITAG_T_TAG_FULL_PERIOD);
280 } else {
281 // Manchester: Loaded, then unloaded |--__|
282 HIGH(GPIO_SSC_DOUT);
283 while(AT91C_BASE_TC0->TC_CV < T0*HITAG_T_TAG_HALF_PERIOD);
284 LOW(GPIO_SSC_DOUT);
285 while(AT91C_BASE_TC0->TC_CV < T0*HITAG_T_TAG_FULL_PERIOD);
286 }
287 LED_A_OFF();
288 }
289
290 static void hitag_send_frame(const byte_t* frame, size_t frame_len)
291 {
292 // Send start of frame
293 for(size_t i=0; i<5; i++) {
294 hitag_send_bit(1);
295 }
296
297 // Send the content of the frame
298 for(size_t i=0; i<frame_len; i++) {
299 hitag_send_bit((frame[i/8] >> (7-(i%8)))&1);
300 }
301
302 // Drop the modulation
303 LOW(GPIO_SSC_DOUT);
304 }
305
306 void hitag2_handle_reader_command(byte_t* rx, const size_t rxlen, byte_t* tx, size_t* txlen)
307 {
308 byte_t* auth_table;
309 auth_table = (byte_t *)BigBuf_get_addr() + AUTH_TABLE_OFFSET;
310 byte_t rx_air[HITAG_FRAME_LEN];
311
312 // Copy the (original) received frame how it is send over the air
313 memcpy(rx_air,rx,nbytes(rxlen));
314
315 if(tag.crypto_active) {
316 hitag2_cipher_transcrypt(&(tag.cs),rx,rxlen/8,rxlen%8);
317 }
318
319 // Reset the transmission frame length
320 *txlen = 0;
321
322 // Try to find out which command was send by selecting on length (in bits)
323 switch (rxlen) {
324 // Received 11000 from the reader, request for UID, send UID
325 case 05: {
326 // Always send over the air in the clear plaintext mode
327 if(rx_air[0] != 0xC0) {
328 // Unknown frame ?
329 return;
330 }
331 *txlen = 32;
332 memcpy(tx,tag.sectors[0],4);
333 tag.crypto_active = 0;
334 }
335 break;
336
337 // Read/Write command: ..xx x..y yy with yyy == ~xxx, xxx is sector number
338 case 10: {
339 unsigned int sector = (~( ((rx[0]<<2)&0x04) | ((rx[1]>>6)&0x03) ) & 0x07);
340 // Verify complement of sector index
341 if(sector != ((rx[0]>>3)&0x07)) {
342 //DbpString("Transmission error (read/write)");
343 return;
344 }
345
346 switch (rx[0] & 0xC6) {
347 // Read command: 11xx x00y
348 case 0xC0:
349 memcpy(tx,tag.sectors[sector],4);
350 *txlen = 32;
351 break;
352
353 // Inverted Read command: 01xx x10y
354 case 0x44:
355 for (size_t i=0; i<4; i++) {
356 tx[i] = tag.sectors[sector][i] ^ 0xff;
357 }
358 *txlen = 32;
359 break;
360
361 // Write command: 10xx x01y
362 case 0x82:
363 // Prepare write, acknowledge by repeating command
364 memcpy(tx,rx,nbytes(rxlen));
365 *txlen = rxlen;
366 tag.active_sector = sector;
367 tag.state=TAG_STATE_WRITING;
368 break;
369
370 // Unknown command
371 default:
372 Dbprintf("Uknown command: %02x %02x",rx[0],rx[1]);
373 return;
374 break;
375 }
376 }
377 break;
378
379 // Writing data or Reader password
380 case 32: {
381 if(tag.state == TAG_STATE_WRITING) {
382 // These are the sector contents to be written. We don't have to do anything else.
383 memcpy(tag.sectors[tag.active_sector],rx,nbytes(rxlen));
384 tag.state=TAG_STATE_RESET;
385 return;
386 } else {
387 // Received RWD password, respond with configuration and our password
388 if(memcmp(rx,tag.sectors[1],4) != 0) {
389 DbpString("Reader password is wrong");
390 return;
391 }
392 *txlen = 32;
393 memcpy(tx,tag.sectors[3],4);
394 }
395 }
396 break;
397
398 // Received RWD authentication challenge and respnse
399 case 64: {
400 // Store the authentication attempt
401 if (auth_table_len < (AUTH_TABLE_LENGTH-8)) {
402 memcpy(auth_table+auth_table_len,rx,8);
403 auth_table_len += 8;
404 }
405
406 // Reset the cipher state
407 hitag2_cipher_reset(&tag,rx);
408 // Check if the authentication was correct
409 if(!hitag2_cipher_authenticate(&(tag.cs),rx+4)) {
410 // The reader failed to authenticate, do nothing
411 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]);
412 return;
413 }
414 // Succesful, but commented out reporting back to the Host, this may delay to much.
415 // 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]);
416
417 // Activate encryption algorithm for all further communication
418 tag.crypto_active = 1;
419
420 // Use the tag password as response
421 memcpy(tx,tag.sectors[3],4);
422 *txlen = 32;
423 }
424 break;
425 }
426
427 // LogTraceHitag(rx,rxlen,0,0,false);
428 // LogTraceHitag(tx,*txlen,0,0,true);
429
430 if(tag.crypto_active) {
431 hitag2_cipher_transcrypt(&(tag.cs), tx, *txlen/8, *txlen%8);
432 }
433 }
434
435 static void hitag_reader_send_bit(int bit) {
436 LED_A_ON();
437 // Reset clock for the next bit
438 AT91C_BASE_TC0->TC_CCR = AT91C_TC_SWTRG;
439
440 // Binary puls length modulation (BPLM) is used to encode the data stream
441 // This means that a transmission of a one takes longer than that of a zero
442
443 // Enable modulation, which means, drop the the field
444 HIGH(GPIO_SSC_DOUT);
445
446 // Wait for 4-10 times the carrier period
447 while(AT91C_BASE_TC0->TC_CV < T0*6);
448 // SpinDelayUs(8*8);
449
450 // Disable modulation, just activates the field again
451 LOW(GPIO_SSC_DOUT);
452
453 if(bit == 0) {
454 // Zero bit: |_-|
455 while(AT91C_BASE_TC0->TC_CV < T0*22);
456 // SpinDelayUs(16*8);
457 } else {
458 // One bit: |_--|
459 while(AT91C_BASE_TC0->TC_CV < T0*28);
460 // SpinDelayUs(22*8);
461 }
462 LED_A_OFF();
463 }
464
465 static void hitag_reader_send_frame(const byte_t* frame, size_t frame_len)
466 {
467 // Send the content of the frame
468 for(size_t i=0; i<frame_len; i++) {
469 hitag_reader_send_bit((frame[i/8] >> (7-(i%8)))&1);
470 }
471 // Send EOF
472 AT91C_BASE_TC0->TC_CCR = AT91C_TC_SWTRG;
473 // Enable modulation, which means, drop the the field
474 HIGH(GPIO_SSC_DOUT);
475 // Wait for 4-10 times the carrier period
476 while(AT91C_BASE_TC0->TC_CV < T0*6);
477 // Disable modulation, just activates the field again
478 LOW(GPIO_SSC_DOUT);
479 }
480
481 size_t blocknr;
482
483 bool hitag2_password(byte_t* rx, const size_t rxlen, byte_t* tx, size_t* txlen) {
484 // Reset the transmission frame length
485 *txlen = 0;
486
487 // Try to find out which command was send by selecting on length (in bits)
488 switch (rxlen) {
489 // No answer, try to resurrect
490 case 0: {
491 // Stop if there is no answer (after sending password)
492 if (bPwd) {
493 DbpString("Password failed!");
494 return false;
495 }
496 *txlen = 5;
497 memcpy(tx,"\xc0",nbytes(*txlen));
498 } break;
499
500 // Received UID, tag password
501 case 32: {
502 if (!bPwd) {
503 *txlen = 32;
504 memcpy(tx,password,4);
505 bPwd = true;
506 memcpy(tag.sectors[blocknr],rx,4);
507 blocknr++;
508 } else {
509
510 if(blocknr == 1){
511 //store password in block1, the TAG answers with Block3, but we need the password in memory
512 memcpy(tag.sectors[blocknr],tx,4);
513 }else{
514 memcpy(tag.sectors[blocknr],rx,4);
515 }
516
517 blocknr++;
518 if (blocknr > 7) {
519 DbpString("Read succesful!");
520 bSuccessful = true;
521 return false;
522 }
523 *txlen = 10;
524 tx[0] = 0xc0 | (blocknr << 3) | ((blocknr^7) >> 2);
525 tx[1] = ((blocknr^7) << 6);
526 }
527 } break;
528
529 // Unexpected response
530 default: {
531 Dbprintf("Uknown frame length: %d",rxlen);
532 return false;
533 } break;
534 }
535 return true;
536 }
537
538 bool hitag2_crypto(byte_t* rx, const size_t rxlen, byte_t* tx, size_t* txlen) {
539 // Reset the transmission frame length
540 *txlen = 0;
541
542 if(bCrypto) {
543 hitag2_cipher_transcrypt(&cipher_state,rx,rxlen/8,rxlen%8);
544 }
545
546 // Try to find out which command was send by selecting on length (in bits)
547 switch (rxlen) {
548 // No answer, try to resurrect
549 case 0: {
550 // Stop if there is no answer while we are in crypto mode (after sending NrAr)
551 if (bCrypto) {
552 // Failed during authentication
553 if (bAuthenticating) {
554 DbpString("Authentication failed!");
555 return false;
556 } else {
557 // Failed reading a block, could be (read/write) locked, skip block and re-authenticate
558 if (blocknr == 1) {
559 // Write the low part of the key in memory
560 memcpy(tag.sectors[1],key+2,4);
561 } else if (blocknr == 2) {
562 // Write the high part of the key in memory
563 tag.sectors[2][0] = 0x00;
564 tag.sectors[2][1] = 0x00;
565 tag.sectors[2][2] = key[0];
566 tag.sectors[2][3] = key[1];
567 } else {
568 // Just put zero's in the memory (of the unreadable block)
569 memset(tag.sectors[blocknr],0x00,4);
570 }
571 blocknr++;
572 bCrypto = false;
573 }
574 } else {
575 *txlen = 5;
576 memcpy(tx,"\xc0",nbytes(*txlen));
577 }
578 } break;
579
580 // Received UID, crypto tag answer
581 case 32: {
582 if (!bCrypto) {
583 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;
584 uint32_t ui32uid = rx[0] | ((uint32_t)rx[1]) << 8 | ((uint32_t)rx[2]) << 16 | ((uint32_t)rx[3]) << 24;
585 cipher_state = _hitag2_init(rev64(ui64key), rev32(ui32uid), 0);
586 memset(tx,0x00,4);
587 memset(tx+4,0xff,4);
588 hitag2_cipher_transcrypt(&cipher_state,tx+4,4,0);
589 *txlen = 64;
590 bCrypto = true;
591 bAuthenticating = true;
592 } else {
593 // Check if we received answer tag (at)
594 if (bAuthenticating) {
595 bAuthenticating = false;
596 } else {
597 // Store the received block
598 memcpy(tag.sectors[blocknr],rx,4);
599 blocknr++;
600 }
601 if (blocknr > 7) {
602 DbpString("Read succesful!");
603 bSuccessful = true;
604 return false;
605 }
606 *txlen = 10;
607 tx[0] = 0xc0 | (blocknr << 3) | ((blocknr^7) >> 2);
608 tx[1] = ((blocknr^7) << 6);
609 }
610 } break;
611
612 // Unexpected response
613 default: {
614 Dbprintf("Uknown frame length: %d",rxlen);
615 return false;
616 } break;
617 }
618
619
620 if(bCrypto) {
621 // We have to return now to avoid double encryption
622 if (!bAuthenticating) {
623 hitag2_cipher_transcrypt(&cipher_state,tx,*txlen/8,*txlen%8);
624 }
625 }
626
627 return true;
628 }
629
630
631 bool hitag2_authenticate(byte_t* rx, const size_t rxlen, byte_t* tx, size_t* txlen) {
632 // Reset the transmission frame length
633 *txlen = 0;
634
635 // Try to find out which command was send by selecting on length (in bits)
636 switch (rxlen) {
637 // No answer, try to resurrect
638 case 0: {
639 // Stop if there is no answer while we are in crypto mode (after sending NrAr)
640 if (bCrypto) {
641 DbpString("Authentication failed!");
642 return false;
643 }
644 *txlen = 5;
645 memcpy(tx,"\xc0",nbytes(*txlen));
646 } break;
647
648 // Received UID, crypto tag answer
649 case 32: {
650 if (!bCrypto) {
651 *txlen = 64;
652 memcpy(tx,NrAr,8);
653 bCrypto = true;
654 } else {
655 DbpString("Authentication succesful!");
656 // We are done... for now
657 return false;
658 }
659 } break;
660
661 // Unexpected response
662 default: {
663 Dbprintf("Uknown frame length: %d",rxlen);
664 return false;
665 } break;
666 }
667
668 return true;
669 }
670
671 bool hitag2_test_auth_attempts(byte_t* rx, const size_t rxlen, byte_t* tx, size_t* txlen) {
672
673 byte_t* auth_table;
674 auth_table = (byte_t *)BigBuf_get_addr() + AUTH_TABLE_OFFSET;
675
676 // Reset the transmission frame length
677 *txlen = 0;
678
679 // Try to find out which command was send by selecting on length (in bits)
680 switch (rxlen) {
681 // No answer, try to resurrect
682 case 0: {
683 // Stop if there is no answer while we are in crypto mode (after sending NrAr)
684 if (bCrypto) {
685 Dbprintf("auth: %02x%02x%02x%02x%02x%02x%02x%02x Failed, removed entry!",NrAr[0],NrAr[1],NrAr[2],NrAr[3],NrAr[4],NrAr[5],NrAr[6],NrAr[7]);
686
687 // Removing failed entry from authentiations table
688 memcpy(auth_table+auth_table_pos,auth_table+auth_table_pos+8,8);
689 auth_table_len -= 8;
690
691 // Return if we reached the end of the authentiactions table
692 bCrypto = false;
693 if (auth_table_pos == auth_table_len) {
694 return false;
695 }
696
697 // Copy the next authentication attempt in row (at the same position, b/c we removed last failed entry)
698 memcpy(NrAr,auth_table+auth_table_pos,8);
699 }
700 *txlen = 5;
701 memcpy(tx,"\xc0",nbytes(*txlen));
702 } break;
703
704 // Received UID, crypto tag answer, or read block response
705 case 32: {
706 if (!bCrypto) {
707 *txlen = 64;
708 memcpy(tx,NrAr,8);
709 bCrypto = true;
710 } else {
711 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]);
712 bCrypto = false;
713 if ((auth_table_pos+8) == auth_table_len) {
714 return false;
715 }
716 auth_table_pos += 8;
717 memcpy(NrAr,auth_table+auth_table_pos,8);
718 }
719 } break;
720
721 default: {
722 Dbprintf("Uknown frame length: %d",rxlen);
723 return false;
724 } break;
725 }
726
727 return true;
728 }
729
730 void SnoopHitag(uint32_t type) {
731 int frame_count;
732 int response;
733 int overflow;
734 bool rising_edge;
735 bool reader_frame;
736 int lastbit;
737 bool bSkip;
738 int tag_sof;
739 byte_t rx[HITAG_FRAME_LEN];
740 size_t rxlen=0;
741
742 // Clean up trace and prepare it for storing frames
743 iso14a_set_tracing(TRUE);
744 iso14a_clear_trace();
745
746 auth_table_len = 0;
747 auth_table_pos = 0;
748 byte_t* auth_table;
749 auth_table = (byte_t *)BigBuf_get_addr() + AUTH_TABLE_OFFSET;
750 memset(auth_table, 0x00, AUTH_TABLE_LENGTH);
751
752 DbpString("Starting Hitag2 snoop");
753 LED_D_ON();
754
755 // Set up eavesdropping mode, frequency divisor which will drive the FPGA
756 // and analog mux selection.
757 FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
758 FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_EDGE_DETECT | FPGA_LF_EDGE_DETECT_TOGGLE_MODE);
759 FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
760 SetAdcMuxFor(GPIO_MUXSEL_LOPKD);
761 RELAY_OFF();
762
763 // Configure output pin that is connected to the FPGA (for modulating)
764 AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
765 AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT;
766
767 // Disable modulation, we are going to eavesdrop, not modulate ;)
768 LOW(GPIO_SSC_DOUT);
769
770 // Enable Peripheral Clock for TIMER_CLOCK1, used to capture edges of the reader frames
771 AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC1);
772 AT91C_BASE_PIOA->PIO_BSR = GPIO_SSC_FRAME;
773
774 // Disable timer during configuration
775 AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
776
777 // Capture mode, defaul timer source = MCK/2 (TIMER_CLOCK1), TIOA is external trigger,
778 // external trigger rising edge, load RA on rising edge of TIOA.
779 uint32_t t1_channel_mode = AT91C_TC_CLKS_TIMER_DIV1_CLOCK | AT91C_TC_ETRGEDG_BOTH | AT91C_TC_ABETRG | AT91C_TC_LDRA_BOTH;
780 AT91C_BASE_TC1->TC_CMR = t1_channel_mode;
781
782 // Enable and reset counter
783 AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
784
785 // Reset the received frame, frame count and timing info
786 memset(rx,0x00,sizeof(rx));
787 frame_count = 0;
788 response = 0;
789 overflow = 0;
790 reader_frame = false;
791 lastbit = 1;
792 bSkip = true;
793 tag_sof = 4;
794
795 while(!BUTTON_PRESS()) {
796 // Watchdog hit
797 WDT_HIT();
798
799 // Receive frame, watch for at most T0*EOF periods
800 while (AT91C_BASE_TC1->TC_CV < T0*HITAG_T_EOF) {
801 // Check if rising edge in modulation is detected
802 if(AT91C_BASE_TC1->TC_SR & AT91C_TC_LDRAS) {
803 // Retrieve the new timing values
804 int ra = (AT91C_BASE_TC1->TC_RA/T0);
805
806 // Find out if we are dealing with a rising or falling edge
807 rising_edge = (AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_FRAME) > 0;
808
809 // Shorter periods will only happen with reader frames
810 if (!reader_frame && rising_edge && ra < HITAG_T_TAG_CAPTURE_ONE_HALF) {
811 // Switch from tag to reader capture
812 LED_C_OFF();
813 reader_frame = true;
814 memset(rx,0x00,sizeof(rx));
815 rxlen = 0;
816 }
817
818 // Only handle if reader frame and rising edge, or tag frame and falling edge
819 if (reader_frame != rising_edge) {
820 overflow += ra;
821 continue;
822 }
823
824 // Add the buffered timing values of earlier captured edges which were skipped
825 ra += overflow;
826 overflow = 0;
827
828 if (reader_frame) {
829 LED_B_ON();
830 // Capture reader frame
831 if(ra >= HITAG_T_STOP) {
832 if (rxlen != 0) {
833 //DbpString("wierd0?");
834 }
835 // Capture the T0 periods that have passed since last communication or field drop (reset)
836 response = (ra - HITAG_T_LOW);
837 } else if(ra >= HITAG_T_1_MIN ) {
838 // '1' bit
839 rx[rxlen / 8] |= 1 << (7-(rxlen%8));
840 rxlen++;
841 } else if(ra >= HITAG_T_0_MIN) {
842 // '0' bit
843 rx[rxlen / 8] |= 0 << (7-(rxlen%8));
844 rxlen++;
845 } else {
846 // Ignore wierd value, is to small to mean anything
847 }
848 } else {
849 LED_C_ON();
850 // Capture tag frame (manchester decoding using only falling edges)
851 if(ra >= HITAG_T_EOF) {
852 if (rxlen != 0) {
853 //DbpString("wierd1?");
854 }
855 // Capture the T0 periods that have passed since last communication or field drop (reset)
856 // We always recieve a 'one' first, which has the falling edge after a half period |-_|
857 response = ra-HITAG_T_TAG_HALF_PERIOD;
858 } else if(ra >= HITAG_T_TAG_CAPTURE_FOUR_HALF) {
859 // Manchester coding example |-_|_-|-_| (101)
860 rx[rxlen / 8] |= 0 << (7-(rxlen%8));
861 rxlen++;
862 rx[rxlen / 8] |= 1 << (7-(rxlen%8));
863 rxlen++;
864 } else if(ra >= HITAG_T_TAG_CAPTURE_THREE_HALF) {
865 // Manchester coding example |_-|...|_-|-_| (0...01)
866 rx[rxlen / 8] |= 0 << (7-(rxlen%8));
867 rxlen++;
868 // We have to skip this half period at start and add the 'one' the second time
869 if (!bSkip) {
870 rx[rxlen / 8] |= 1 << (7-(rxlen%8));
871 rxlen++;
872 }
873 lastbit = !lastbit;
874 bSkip = !bSkip;
875 } else if(ra >= HITAG_T_TAG_CAPTURE_TWO_HALF) {
876 // Manchester coding example |_-|_-| (00) or |-_|-_| (11)
877 if (tag_sof) {
878 // Ignore bits that are transmitted during SOF
879 tag_sof--;
880 } else {
881 // bit is same as last bit
882 rx[rxlen / 8] |= lastbit << (7-(rxlen%8));
883 rxlen++;
884 }
885 } else {
886 // Ignore wierd value, is to small to mean anything
887 }
888 }
889 }
890 }
891
892 // Check if frame was captured
893 if(rxlen > 0) {
894 frame_count++;
895 if (!LogTraceHitag(rx,rxlen,response,0,reader_frame)) {
896 DbpString("Trace full");
897 break;
898 }
899
900 // Check if we recognize a valid authentication attempt
901 if (nbytes(rxlen) == 8) {
902 // Store the authentication attempt
903 if (auth_table_len < (AUTH_TABLE_LENGTH-8)) {
904 memcpy(auth_table+auth_table_len,rx,8);
905 auth_table_len += 8;
906 }
907 }
908
909 // Reset the received frame and response timing info
910 memset(rx,0x00,sizeof(rx));
911 response = 0;
912 reader_frame = false;
913 lastbit = 1;
914 bSkip = true;
915 tag_sof = 4;
916 overflow = 0;
917
918 LED_B_OFF();
919 LED_C_OFF();
920 } else {
921 // Save the timer overflow, will be 0 when frame was received
922 overflow += (AT91C_BASE_TC1->TC_CV/T0);
923 }
924 // Reset the frame length
925 rxlen = 0;
926 // Reset the timer to restart while-loop that receives frames
927 AT91C_BASE_TC1->TC_CCR = AT91C_TC_SWTRG;
928 }
929 LED_A_ON();
930 LED_B_OFF();
931 LED_C_OFF();
932 LED_D_OFF();
933 AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
934 AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS;
935 FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
936 LED_A_OFF();
937
938 // Dbprintf("frame received: %d",frame_count);
939 // Dbprintf("Authentication Attempts: %d",(auth_table_len/8));
940 // DbpString("All done");
941 }
942
943 void SimulateHitagTag(bool tag_mem_supplied, byte_t* data) {
944 int frame_count;
945 int response;
946 int overflow;
947 byte_t rx[HITAG_FRAME_LEN];
948 size_t rxlen=0;
949 byte_t tx[HITAG_FRAME_LEN];
950 size_t txlen=0;
951 bool bQuitTraceFull = false;
952 bQuiet = false;
953
954 // Clean up trace and prepare it for storing frames
955 iso14a_set_tracing(TRUE);
956 iso14a_clear_trace();
957 auth_table_len = 0;
958 auth_table_pos = 0;
959 byte_t* auth_table;
960 auth_table = (byte_t *)BigBuf_get_addr() + AUTH_TABLE_OFFSET;
961 memset(auth_table, 0x00, AUTH_TABLE_LENGTH);
962
963 DbpString("Starting Hitag2 simulation");
964 LED_D_ON();
965 hitag2_init();
966
967 if (tag_mem_supplied) {
968 DbpString("Loading hitag2 memory...");
969 memcpy((byte_t*)tag.sectors,data,48);
970 }
971
972 uint32_t block = 0;
973 for (size_t i=0; i<12; i++) {
974 for (size_t j=0; j<4; j++) {
975 block <<= 8;
976 block |= tag.sectors[i][j];
977 }
978 Dbprintf("| %d | %08x |",i,block);
979 }
980
981 // Set up simulator mode, frequency divisor which will drive the FPGA
982 // and analog mux selection.
983 FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
984 FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_EDGE_DETECT | FPGA_LF_EDGE_DETECT_READER_FIELD);
985 FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
986 SetAdcMuxFor(GPIO_MUXSEL_LOPKD);
987 RELAY_OFF();
988
989 // Configure output pin that is connected to the FPGA (for modulating)
990 AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
991 AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT;
992
993 // Disable modulation at default, which means release resistance
994 LOW(GPIO_SSC_DOUT);
995
996 // Enable Peripheral Clock for TIMER_CLOCK0, used to measure exact timing before answering
997 AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC0);
998
999 // Enable Peripheral Clock for TIMER_CLOCK1, used to capture edges of the reader frames
1000 AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC1);
1001 AT91C_BASE_PIOA->PIO_BSR = GPIO_SSC_FRAME;
1002
1003 // Disable timer during configuration
1004 AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
1005
1006 // Capture mode, default timer source = MCK/2 (TIMER_CLOCK1), TIOA is external trigger,
1007 // external trigger rising edge, load RA on rising edge of TIOA.
1008 AT91C_BASE_TC1->TC_CMR = AT91C_TC_CLKS_TIMER_DIV1_CLOCK | AT91C_TC_ETRGEDG_RISING | AT91C_TC_ABETRG | AT91C_TC_LDRA_RISING;
1009
1010 // Reset the received frame, frame count and timing info
1011 memset(rx,0x00,sizeof(rx));
1012 frame_count = 0;
1013 response = 0;
1014 overflow = 0;
1015
1016 // Enable and reset counter
1017 AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
1018
1019 while(!BUTTON_PRESS()) {
1020 // Watchdog hit
1021 WDT_HIT();
1022
1023 // Receive frame, watch for at most T0*EOF periods
1024 while (AT91C_BASE_TC1->TC_CV < T0*HITAG_T_EOF) {
1025 // Check if rising edge in modulation is detected
1026 if(AT91C_BASE_TC1->TC_SR & AT91C_TC_LDRAS) {
1027 // Retrieve the new timing values
1028 int ra = (AT91C_BASE_TC1->TC_RA/T0) + overflow;
1029 overflow = 0;
1030
1031 // Reset timer every frame, we have to capture the last edge for timing
1032 AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
1033
1034 LED_B_ON();
1035
1036 // Capture reader frame
1037 if(ra >= HITAG_T_STOP) {
1038 if (rxlen != 0) {
1039 //DbpString("wierd0?");
1040 }
1041 // Capture the T0 periods that have passed since last communication or field drop (reset)
1042 response = (ra - HITAG_T_LOW);
1043 } else if(ra >= HITAG_T_1_MIN ) {
1044 // '1' bit
1045 rx[rxlen / 8] |= 1 << (7-(rxlen%8));
1046 rxlen++;
1047 } else if(ra >= HITAG_T_0_MIN) {
1048 // '0' bit
1049 rx[rxlen / 8] |= 0 << (7-(rxlen%8));
1050 rxlen++;
1051 } else {
1052 // Ignore wierd value, is to small to mean anything
1053 }
1054 }
1055 }
1056
1057 // Check if frame was captured
1058 if(rxlen > 4) {
1059 frame_count++;
1060 if (!bQuiet) {
1061 if (!LogTraceHitag(rx,rxlen,response,0,true)) {
1062 DbpString("Trace full");
1063 if (bQuitTraceFull) {
1064 break;
1065 } else {
1066 bQuiet = true;
1067 }
1068 }
1069 }
1070
1071 // Disable timer 1 with external trigger to avoid triggers during our own modulation
1072 AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
1073
1074 // Process the incoming frame (rx) and prepare the outgoing frame (tx)
1075 hitag2_handle_reader_command(rx,rxlen,tx,&txlen);
1076
1077 // Wait for HITAG_T_WAIT_1 carrier periods after the last reader bit,
1078 // not that since the clock counts since the rising edge, but T_Wait1 is
1079 // with respect to the falling edge, we need to wait actually (T_Wait1 - T_Low)
1080 // periods. The gap time T_Low varies (4..10). All timer values are in
1081 // terms of T0 units
1082 while(AT91C_BASE_TC0->TC_CV < T0*(HITAG_T_WAIT_1-HITAG_T_LOW));
1083
1084 // Send and store the tag answer (if there is any)
1085 if (txlen) {
1086 // Transmit the tag frame
1087 hitag_send_frame(tx,txlen);
1088 // Store the frame in the trace
1089 if (!bQuiet) {
1090 if (!LogTraceHitag(tx,txlen,0,0,false)) {
1091 DbpString("Trace full");
1092 if (bQuitTraceFull) {
1093 break;
1094 } else {
1095 bQuiet = true;
1096 }
1097 }
1098 }
1099 }
1100
1101 // Reset the received frame and response timing info
1102 memset(rx,0x00,sizeof(rx));
1103 response = 0;
1104
1105 // Enable and reset external trigger in timer for capturing future frames
1106 AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
1107 LED_B_OFF();
1108 }
1109 // Reset the frame length
1110 rxlen = 0;
1111 // Save the timer overflow, will be 0 when frame was received
1112 overflow += (AT91C_BASE_TC1->TC_CV/T0);
1113 // Reset the timer to restart while-loop that receives frames
1114 AT91C_BASE_TC1->TC_CCR = AT91C_TC_SWTRG;
1115 }
1116 LED_B_OFF();
1117 LED_D_OFF();
1118 AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
1119 AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS;
1120 FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
1121
1122 DbpString("Sim Stopped");
1123
1124 }
1125
1126 void ReaderHitag(hitag_function htf, hitag_data* htd) {
1127 int frame_count;
1128 int response;
1129 byte_t rx[HITAG_FRAME_LEN];
1130 size_t rxlen=0;
1131 byte_t txbuf[HITAG_FRAME_LEN];
1132 byte_t* tx = txbuf;
1133 size_t txlen=0;
1134 int lastbit;
1135 bool bSkip;
1136 int reset_sof;
1137 int tag_sof;
1138 int t_wait = HITAG_T_WAIT_MAX;
1139 bool bStop;
1140 bool bQuitTraceFull = false;
1141
1142 FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
1143 // Reset the return status
1144 bSuccessful = false;
1145
1146 // Clean up trace and prepare it for storing frames
1147 iso14a_set_tracing(TRUE);
1148 iso14a_clear_trace();
1149 byte_t* auth_table;
1150 auth_table = (byte_t *)BigBuf_get_addr() + AUTH_TABLE_OFFSET;
1151
1152 DbpString("Starting Hitag reader family");
1153
1154 // Check configuration
1155 switch(htf) {
1156 case RHT2F_PASSWORD: {
1157 Dbprintf("List identifier in password mode");
1158 memcpy(password,htd->pwd.password,4);
1159 blocknr = 0;
1160 bQuitTraceFull = false;
1161 bQuiet = false;
1162 bPwd = false;
1163 } break;
1164
1165 case RHT2F_AUTHENTICATE: {
1166 DbpString("Authenticating using nr,ar pair:");
1167 memcpy(NrAr,htd->auth.NrAr,8);
1168 Dbhexdump(8,NrAr,false);
1169 bQuiet = false;
1170 bCrypto = false;
1171 bAuthenticating = false;
1172 bQuitTraceFull = true;
1173 } break;
1174
1175 case RHT2F_CRYPTO: {
1176 DbpString("Authenticating using key:");
1177 memcpy(key,htd->crypto.key,4); //HACK; 4 or 6?? I read both in the code.
1178 Dbhexdump(6,key,false);
1179 blocknr = 0;
1180 bQuiet = false;
1181 bCrypto = false;
1182 bAuthenticating = false;
1183 bQuitTraceFull = true;
1184 } break;
1185
1186 case RHT2F_TEST_AUTH_ATTEMPTS: {
1187 Dbprintf("Testing %d authentication attempts",(auth_table_len/8));
1188 auth_table_pos = 0;
1189 memcpy(NrAr,auth_table,8);
1190 bQuitTraceFull = false;
1191 bQuiet = false;
1192 bCrypto = false;
1193 } break;
1194
1195 default: {
1196 Dbprintf("Error, unknown function: %d",htf);
1197 return;
1198 } break;
1199 }
1200
1201 LED_D_ON();
1202 hitag2_init();
1203
1204 // Configure output and enable pin that is connected to the FPGA (for modulating)
1205 AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
1206 AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT;
1207
1208 // Set fpga in edge detect with reader field, we can modulate as reader now
1209 FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_EDGE_DETECT | FPGA_LF_EDGE_DETECT_READER_FIELD);
1210
1211 // Set Frequency divisor which will drive the FPGA and analog mux selection
1212 FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
1213 SetAdcMuxFor(GPIO_MUXSEL_LOPKD);
1214 RELAY_OFF();
1215
1216 // Disable modulation at default, which means enable the field
1217 LOW(GPIO_SSC_DOUT);
1218
1219 // Give it a bit of time for the resonant antenna to settle.
1220 SpinDelay(30);
1221
1222 // Enable Peripheral Clock for TIMER_CLOCK0, used to measure exact timing before answering
1223 AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC0);
1224
1225 // Enable Peripheral Clock for TIMER_CLOCK1, used to capture edges of the tag frames
1226 AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC1);
1227 AT91C_BASE_PIOA->PIO_BSR = GPIO_SSC_FRAME;
1228
1229 // Disable timer during configuration
1230 AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
1231
1232 // Capture mode, defaul timer source = MCK/2 (TIMER_CLOCK1), TIOA is external trigger,
1233 // external trigger rising edge, load RA on falling edge of TIOA.
1234 AT91C_BASE_TC1->TC_CMR = AT91C_TC_CLKS_TIMER_DIV1_CLOCK | AT91C_TC_ETRGEDG_FALLING | AT91C_TC_ABETRG | AT91C_TC_LDRA_FALLING;
1235
1236 // Enable and reset counters
1237 AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
1238 AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
1239
1240 // Reset the received frame, frame count and timing info
1241 frame_count = 0;
1242 response = 0;
1243 lastbit = 1;
1244 bStop = false;
1245
1246 // Tag specific configuration settings (sof, timings, etc.)
1247 if (htf < 10){
1248 // hitagS settings
1249 reset_sof = 1;
1250 t_wait = 200;
1251 DbpString("Configured for hitagS reader");
1252 } else if (htf < 20) {
1253 // hitag1 settings
1254 reset_sof = 1;
1255 t_wait = 200;
1256 DbpString("Configured for hitag1 reader");
1257 } else if (htf < 30) {
1258 // hitag2 settings
1259 reset_sof = 4;
1260 t_wait = HITAG_T_WAIT_2;
1261 DbpString("Configured for hitag2 reader");
1262 } else {
1263 Dbprintf("Error, unknown hitag reader type: %d",htf);
1264 return;
1265 }
1266
1267 while(!bStop && !BUTTON_PRESS()) {
1268 // Watchdog hit
1269 WDT_HIT();
1270
1271 // Check if frame was captured and store it
1272 if(rxlen > 0) {
1273 frame_count++;
1274 if (!bQuiet) {
1275 if (!LogTraceHitag(rx,rxlen,response,0,false)) {
1276 DbpString("Trace full");
1277 if (bQuitTraceFull) {
1278 break;
1279 } else {
1280 bQuiet = true;
1281 }
1282 }
1283 }
1284 }
1285
1286 // By default reset the transmission buffer
1287 tx = txbuf;
1288 switch(htf) {
1289 case RHT2F_PASSWORD: {
1290 bStop = !hitag2_password(rx,rxlen,tx,&txlen);
1291 } break;
1292 case RHT2F_AUTHENTICATE: {
1293 bStop = !hitag2_authenticate(rx,rxlen,tx,&txlen);
1294 } break;
1295 case RHT2F_CRYPTO: {
1296 bStop = !hitag2_crypto(rx,rxlen,tx,&txlen);
1297 } break;
1298 case RHT2F_TEST_AUTH_ATTEMPTS: {
1299 bStop = !hitag2_test_auth_attempts(rx,rxlen,tx,&txlen);
1300 } break;
1301 default: {
1302 Dbprintf("Error, unknown function: %d",htf);
1303 return;
1304 } break;
1305 }
1306
1307 // Send and store the reader command
1308 // Disable timer 1 with external trigger to avoid triggers during our own modulation
1309 AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
1310
1311 // Wait for HITAG_T_WAIT_2 carrier periods after the last tag bit before transmitting,
1312 // Since the clock counts since the last falling edge, a 'one' means that the
1313 // falling edge occured halfway the period. with respect to this falling edge,
1314 // we need to wait (T_Wait2 + half_tag_period) when the last was a 'one'.
1315 // All timer values are in terms of T0 units
1316 while(AT91C_BASE_TC0->TC_CV < T0*(t_wait+(HITAG_T_TAG_HALF_PERIOD*lastbit)));
1317
1318 // Transmit the reader frame
1319 hitag_reader_send_frame(tx,txlen);
1320
1321 // Enable and reset external trigger in timer for capturing future frames
1322 AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
1323
1324 // Add transmitted frame to total count
1325 if(txlen > 0) {
1326 frame_count++;
1327 if (!bQuiet) {
1328 // Store the frame in the trace
1329 if (!LogTraceHitag(tx,txlen,HITAG_T_WAIT_2,0,true)) {
1330 if (bQuitTraceFull) {
1331 break;
1332 } else {
1333 bQuiet = true;
1334 }
1335 }
1336 }
1337 }
1338
1339 // Reset values for receiving frames
1340 memset(rx,0x00,sizeof(rx));
1341 rxlen = 0;
1342 lastbit = 1;
1343 bSkip = true;
1344 tag_sof = reset_sof;
1345 response = 0;
1346
1347 // Receive frame, watch for at most T0*EOF periods
1348 while (AT91C_BASE_TC1->TC_CV < T0*HITAG_T_WAIT_MAX) {
1349 // Check if falling edge in tag modulation is detected
1350 if(AT91C_BASE_TC1->TC_SR & AT91C_TC_LDRAS) {
1351 // Retrieve the new timing values
1352 int ra = (AT91C_BASE_TC1->TC_RA/T0);
1353
1354 // Reset timer every frame, we have to capture the last edge for timing
1355 AT91C_BASE_TC0->TC_CCR = AT91C_TC_SWTRG;
1356
1357 LED_B_ON();
1358
1359 // Capture tag frame (manchester decoding using only falling edges)
1360 if(ra >= HITAG_T_EOF) {
1361 if (rxlen != 0) {
1362 //DbpString("wierd1?");
1363 }
1364 // Capture the T0 periods that have passed since last communication or field drop (reset)
1365 // We always recieve a 'one' first, which has the falling edge after a half period |-_|
1366 response = ra-HITAG_T_TAG_HALF_PERIOD;
1367 } else if(ra >= HITAG_T_TAG_CAPTURE_FOUR_HALF) {
1368 // Manchester coding example |-_|_-|-_| (101)
1369 rx[rxlen / 8] |= 0 << (7-(rxlen%8));
1370 rxlen++;
1371 rx[rxlen / 8] |= 1 << (7-(rxlen%8));
1372 rxlen++;
1373 } else if(ra >= HITAG_T_TAG_CAPTURE_THREE_HALF) {
1374 // Manchester coding example |_-|...|_-|-_| (0...01)
1375 rx[rxlen / 8] |= 0 << (7-(rxlen%8));
1376 rxlen++;
1377 // We have to skip this half period at start and add the 'one' the second time
1378 if (!bSkip) {
1379 rx[rxlen / 8] |= 1 << (7-(rxlen%8));
1380 rxlen++;
1381 }
1382 lastbit = !lastbit;
1383 bSkip = !bSkip;
1384 } else if(ra >= HITAG_T_TAG_CAPTURE_TWO_HALF) {
1385 // Manchester coding example |_-|_-| (00) or |-_|-_| (11)
1386 if (tag_sof) {
1387 // Ignore bits that are transmitted during SOF
1388 tag_sof--;
1389 } else {
1390 // bit is same as last bit
1391 rx[rxlen / 8] |= lastbit << (7-(rxlen%8));
1392 rxlen++;
1393 }
1394 } else {
1395 // Ignore wierd value, is to small to mean anything
1396 }
1397 }
1398
1399 // We can break this loop if we received the last bit from a frame
1400 if (AT91C_BASE_TC1->TC_CV > T0*HITAG_T_EOF) {
1401 if (rxlen>0) break;
1402 }
1403 }
1404 }
1405 LED_B_OFF();
1406 LED_D_OFF();
1407 AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
1408 AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS;
1409 FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
1410 Dbprintf("frame received: %d",frame_count);
1411 DbpString("All done");
1412 cmd_send(CMD_ACK,bSuccessful,0,0,(byte_t*)tag.sectors,48);
1413 }
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