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1 //-----------------------------------------------------------------------------
2 // Merlok - June 2011, 2012
3 // Gerhard de Koning Gans - May 2008
4 // Hagen Fritsch - June 2010
5 //
6 // This code is licensed to you under the terms of the GNU GPL, version 2 or,
7 // at your option, any later version. See the LICENSE.txt file for the text of
8 // the license.
9 //-----------------------------------------------------------------------------
10 // Routines to support ISO 14443 type A.
11 //-----------------------------------------------------------------------------
12
13 #include "proxmark3.h"
14 #include "apps.h"
15 #include "util.h"
16 #include "string.h"
17 #include "cmd.h"
18 #include "iso14443crc.h"
19 #include "iso14443a.h"
20 #include "crapto1/crapto1.h"
21 #include "mifareutil.h"
22 #include "BigBuf.h"
23 #include "protocols.h"
24 #include "parity.h"
25
26
27 static uint32_t iso14a_timeout;
28 int rsamples = 0;
29 uint8_t trigger = 0;
30 // the block number for the ISO14443-4 PCB
31 static uint8_t iso14_pcb_blocknum = 0;
32
33 //
34 // ISO14443 timing:
35 //
36 // minimum time between the start bits of consecutive transfers from reader to tag: 7000 carrier (13.56Mhz) cycles
37 #define REQUEST_GUARD_TIME (7000/16 + 1)
38 // minimum time between last modulation of tag and next start bit from reader to tag: 1172 carrier cycles
39 #define FRAME_DELAY_TIME_PICC_TO_PCD (1172/16 + 1)
40 // bool LastCommandWasRequest = FALSE;
41
42 //
43 // Total delays including SSC-Transfers between ARM and FPGA. These are in carrier clock cycles (1/13,56MHz)
44 //
45 // When the PM acts as reader and is receiving tag data, it takes
46 // 3 ticks delay in the AD converter
47 // 16 ticks until the modulation detector completes and sets curbit
48 // 8 ticks until bit_to_arm is assigned from curbit
49 // 8*16 ticks for the transfer from FPGA to ARM
50 // 4*16 ticks until we measure the time
51 // - 8*16 ticks because we measure the time of the previous transfer
52 #define DELAY_AIR2ARM_AS_READER (3 + 16 + 8 + 8*16 + 4*16 - 8*16)
53
54 // When the PM acts as a reader and is sending, it takes
55 // 4*16 ticks until we can write data to the sending hold register
56 // 8*16 ticks until the SHR is transferred to the Sending Shift Register
57 // 8 ticks until the first transfer starts
58 // 8 ticks later the FPGA samples the data
59 // 1 tick to assign mod_sig_coil
60 #define DELAY_ARM2AIR_AS_READER (4*16 + 8*16 + 8 + 8 + 1)
61
62 // When the PM acts as tag and is receiving it takes
63 // 2 ticks delay in the RF part (for the first falling edge),
64 // 3 ticks for the A/D conversion,
65 // 8 ticks on average until the start of the SSC transfer,
66 // 8 ticks until the SSC samples the first data
67 // 7*16 ticks to complete the transfer from FPGA to ARM
68 // 8 ticks until the next ssp_clk rising edge
69 // 4*16 ticks until we measure the time
70 // - 8*16 ticks because we measure the time of the previous transfer
71 #define DELAY_AIR2ARM_AS_TAG (2 + 3 + 8 + 8 + 7*16 + 8 + 4*16 - 8*16)
72
73 // The FPGA will report its internal sending delay in
74 uint16_t FpgaSendQueueDelay;
75 // the 5 first bits are the number of bits buffered in mod_sig_buf
76 // the last three bits are the remaining ticks/2 after the mod_sig_buf shift
77 #define DELAY_FPGA_QUEUE (FpgaSendQueueDelay<<1)
78
79 // When the PM acts as tag and is sending, it takes
80 // 4*16 ticks until we can write data to the sending hold register
81 // 8*16 ticks until the SHR is transferred to the Sending Shift Register
82 // 8 ticks until the first transfer starts
83 // 8 ticks later the FPGA samples the data
84 // + a varying number of ticks in the FPGA Delay Queue (mod_sig_buf)
85 // + 1 tick to assign mod_sig_coil
86 #define DELAY_ARM2AIR_AS_TAG (4*16 + 8*16 + 8 + 8 + DELAY_FPGA_QUEUE + 1)
87
88 // When the PM acts as sniffer and is receiving tag data, it takes
89 // 3 ticks A/D conversion
90 // 14 ticks to complete the modulation detection
91 // 8 ticks (on average) until the result is stored in to_arm
92 // + the delays in transferring data - which is the same for
93 // sniffing reader and tag data and therefore not relevant
94 #define DELAY_TAG_AIR2ARM_AS_SNIFFER (3 + 14 + 8)
95
96 // When the PM acts as sniffer and is receiving reader data, it takes
97 // 2 ticks delay in analogue RF receiver (for the falling edge of the
98 // start bit, which marks the start of the communication)
99 // 3 ticks A/D conversion
100 // 8 ticks on average until the data is stored in to_arm.
101 // + the delays in transferring data - which is the same for
102 // sniffing reader and tag data and therefore not relevant
103 #define DELAY_READER_AIR2ARM_AS_SNIFFER (2 + 3 + 8)
104
105 //variables used for timing purposes:
106 //these are in ssp_clk cycles:
107 static uint32_t NextTransferTime;
108 static uint32_t LastTimeProxToAirStart;
109 static uint32_t LastProxToAirDuration;
110
111
112
113 // CARD TO READER - manchester
114 // Sequence D: 11110000 modulation with subcarrier during first half
115 // Sequence E: 00001111 modulation with subcarrier during second half
116 // Sequence F: 00000000 no modulation with subcarrier
117 // READER TO CARD - miller
118 // Sequence X: 00001100 drop after half a period
119 // Sequence Y: 00000000 no drop
120 // Sequence Z: 11000000 drop at start
121 #define SEC_D 0xf0
122 #define SEC_E 0x0f
123 #define SEC_F 0x00
124 #define SEC_X 0x0c
125 #define SEC_Y 0x00
126 #define SEC_Z 0xc0
127
128
129 void iso14a_set_trigger(bool enable) {
130 trigger = enable;
131 }
132
133
134 void iso14a_set_timeout(uint32_t timeout) {
135 iso14a_timeout = timeout;
136 if(MF_DBGLEVEL >= 3) Dbprintf("ISO14443A Timeout set to %ld (%dms)", iso14a_timeout, iso14a_timeout / 106);
137 }
138
139
140 void iso14a_set_ATS_timeout(uint8_t *ats) {
141
142 uint8_t tb1;
143 uint8_t fwi;
144 uint32_t fwt;
145
146 if (ats[0] > 1) { // there is a format byte T0
147 if ((ats[1] & 0x20) == 0x20) { // there is an interface byte TB(1)
148 if ((ats[1] & 0x10) == 0x10) { // there is an interface byte TA(1) preceding TB(1)
149 tb1 = ats[3];
150 } else {
151 tb1 = ats[2];
152 }
153 fwi = (tb1 & 0xf0) >> 4; // frame waiting indicator (FWI)
154 fwt = 256 * 16 * (1 << fwi); // frame waiting time (FWT) in 1/fc
155
156 iso14a_set_timeout(fwt/(8*16));
157 }
158 }
159 }
160
161
162 //-----------------------------------------------------------------------------
163 // Generate the parity value for a byte sequence
164 //
165 //-----------------------------------------------------------------------------
166 void GetParity(const uint8_t *pbtCmd, uint16_t iLen, uint8_t *par)
167 {
168 uint16_t paritybit_cnt = 0;
169 uint16_t paritybyte_cnt = 0;
170 uint8_t parityBits = 0;
171
172 for (uint16_t i = 0; i < iLen; i++) {
173 // Generate the parity bits
174 parityBits |= ((oddparity8(pbtCmd[i])) << (7-paritybit_cnt));
175 if (paritybit_cnt == 7) {
176 par[paritybyte_cnt] = parityBits; // save 8 Bits parity
177 parityBits = 0; // and advance to next Parity Byte
178 paritybyte_cnt++;
179 paritybit_cnt = 0;
180 } else {
181 paritybit_cnt++;
182 }
183 }
184
185 // save remaining parity bits
186 par[paritybyte_cnt] = parityBits;
187
188 }
189
190 void AppendCrc14443a(uint8_t* data, int len)
191 {
192 ComputeCrc14443(CRC_14443_A,data,len,data+len,data+len+1);
193 }
194
195 void AppendCrc14443b(uint8_t* data, int len)
196 {
197 ComputeCrc14443(CRC_14443_B,data,len,data+len,data+len+1);
198 }
199
200
201 //=============================================================================
202 // ISO 14443 Type A - Miller decoder
203 //=============================================================================
204 // Basics:
205 // This decoder is used when the PM3 acts as a tag.
206 // The reader will generate "pauses" by temporarily switching of the field.
207 // At the PM3 antenna we will therefore measure a modulated antenna voltage.
208 // The FPGA does a comparison with a threshold and would deliver e.g.:
209 // ........ 1 1 1 1 1 1 0 0 1 1 1 1 1 1 1 1 1 1 0 0 1 1 1 1 1 1 1 1 1 1 .......
210 // The Miller decoder needs to identify the following sequences:
211 // 2 (or 3) ticks pause followed by 6 (or 5) ticks unmodulated: pause at beginning - Sequence Z ("start of communication" or a "0")
212 // 8 ticks without a modulation: no pause - Sequence Y (a "0" or "end of communication" or "no information")
213 // 4 ticks unmodulated followed by 2 (or 3) ticks pause: pause in second half - Sequence X (a "1")
214 // Note 1: the bitstream may start at any time. We therefore need to sync.
215 // Note 2: the interpretation of Sequence Y and Z depends on the preceding sequence.
216 //-----------------------------------------------------------------------------
217 static tUart Uart;
218
219 // Lookup-Table to decide if 4 raw bits are a modulation.
220 // We accept the following:
221 // 0001 - a 3 tick wide pause
222 // 0011 - a 2 tick wide pause, or a three tick wide pause shifted left
223 // 0111 - a 2 tick wide pause shifted left
224 // 1001 - a 2 tick wide pause shifted right
225 const bool Mod_Miller_LUT[] = {
226 FALSE, TRUE, FALSE, TRUE, FALSE, FALSE, FALSE, TRUE,
227 FALSE, TRUE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE
228 };
229 #define IsMillerModulationNibble1(b) (Mod_Miller_LUT[(b & 0x000000F0) >> 4])
230 #define IsMillerModulationNibble2(b) (Mod_Miller_LUT[(b & 0x0000000F)])
231
232 void UartReset()
233 {
234 Uart.state = STATE_UNSYNCD;
235 Uart.bitCount = 0;
236 Uart.len = 0; // number of decoded data bytes
237 Uart.parityLen = 0; // number of decoded parity bytes
238 Uart.shiftReg = 0; // shiftreg to hold decoded data bits
239 Uart.parityBits = 0; // holds 8 parity bits
240 Uart.startTime = 0;
241 Uart.endTime = 0;
242 }
243
244 void UartInit(uint8_t *data, uint8_t *parity)
245 {
246 Uart.output = data;
247 Uart.parity = parity;
248 Uart.fourBits = 0x00000000; // clear the buffer for 4 Bits
249 UartReset();
250 }
251
252 // use parameter non_real_time to provide a timestamp. Set to 0 if the decoder should measure real time
253 static RAMFUNC bool MillerDecoding(uint8_t bit, uint32_t non_real_time)
254 {
255
256 Uart.fourBits = (Uart.fourBits << 8) | bit;
257
258 if (Uart.state == STATE_UNSYNCD) { // not yet synced
259
260 Uart.syncBit = 9999; // not set
261 // The start bit is one ore more Sequence Y followed by a Sequence Z (... 11111111 00x11111). We need to distinguish from
262 // Sequence X followed by Sequence Y followed by Sequence Z (111100x1 11111111 00x11111)
263 // we therefore look for a ...xx11111111111100x11111xxxxxx... pattern
264 // (12 '1's followed by 2 '0's, eventually followed by another '0', followed by 5 '1's)
265 #define ISO14443A_STARTBIT_MASK 0x07FFEF80 // mask is 00000111 11111111 11101111 10000000
266 #define ISO14443A_STARTBIT_PATTERN 0x07FF8F80 // pattern is 00000111 11111111 10001111 10000000
267 if ((Uart.fourBits & (ISO14443A_STARTBIT_MASK >> 0)) == ISO14443A_STARTBIT_PATTERN >> 0) Uart.syncBit = 7;
268 else if ((Uart.fourBits & (ISO14443A_STARTBIT_MASK >> 1)) == ISO14443A_STARTBIT_PATTERN >> 1) Uart.syncBit = 6;
269 else if ((Uart.fourBits & (ISO14443A_STARTBIT_MASK >> 2)) == ISO14443A_STARTBIT_PATTERN >> 2) Uart.syncBit = 5;
270 else if ((Uart.fourBits & (ISO14443A_STARTBIT_MASK >> 3)) == ISO14443A_STARTBIT_PATTERN >> 3) Uart.syncBit = 4;
271 else if ((Uart.fourBits & (ISO14443A_STARTBIT_MASK >> 4)) == ISO14443A_STARTBIT_PATTERN >> 4) Uart.syncBit = 3;
272 else if ((Uart.fourBits & (ISO14443A_STARTBIT_MASK >> 5)) == ISO14443A_STARTBIT_PATTERN >> 5) Uart.syncBit = 2;
273 else if ((Uart.fourBits & (ISO14443A_STARTBIT_MASK >> 6)) == ISO14443A_STARTBIT_PATTERN >> 6) Uart.syncBit = 1;
274 else if ((Uart.fourBits & (ISO14443A_STARTBIT_MASK >> 7)) == ISO14443A_STARTBIT_PATTERN >> 7) Uart.syncBit = 0;
275
276 if (Uart.syncBit != 9999) { // found a sync bit
277 Uart.startTime = non_real_time?non_real_time:(GetCountSspClk() & 0xfffffff8);
278 Uart.startTime -= Uart.syncBit;
279 Uart.endTime = Uart.startTime;
280 Uart.state = STATE_START_OF_COMMUNICATION;
281 }
282
283 } else {
284
285 if (IsMillerModulationNibble1(Uart.fourBits >> Uart.syncBit)) {
286 if (IsMillerModulationNibble2(Uart.fourBits >> Uart.syncBit)) { // Modulation in both halves - error
287 UartReset();
288 } else { // Modulation in first half = Sequence Z = logic "0"
289 if (Uart.state == STATE_MILLER_X) { // error - must not follow after X
290 UartReset();
291 } else {
292 Uart.bitCount++;
293 Uart.shiftReg = (Uart.shiftReg >> 1); // add a 0 to the shiftreg
294 Uart.state = STATE_MILLER_Z;
295 Uart.endTime = Uart.startTime + 8*(9*Uart.len + Uart.bitCount + 1) - 6;
296 if(Uart.bitCount >= 9) { // if we decoded a full byte (including parity)
297 Uart.output[Uart.len++] = (Uart.shiftReg & 0xff);
298 Uart.parityBits <<= 1; // make room for the parity bit
299 Uart.parityBits |= ((Uart.shiftReg >> 8) & 0x01); // store parity bit
300 Uart.bitCount = 0;
301 Uart.shiftReg = 0;
302 if((Uart.len&0x0007) == 0) { // every 8 data bytes
303 Uart.parity[Uart.parityLen++] = Uart.parityBits; // store 8 parity bits
304 Uart.parityBits = 0;
305 }
306 }
307 }
308 }
309 } else {
310 if (IsMillerModulationNibble2(Uart.fourBits >> Uart.syncBit)) { // Modulation second half = Sequence X = logic "1"
311 Uart.bitCount++;
312 Uart.shiftReg = (Uart.shiftReg >> 1) | 0x100; // add a 1 to the shiftreg
313 Uart.state = STATE_MILLER_X;
314 Uart.endTime = Uart.startTime + 8*(9*Uart.len + Uart.bitCount + 1) - 2;
315 if(Uart.bitCount >= 9) { // if we decoded a full byte (including parity)
316 Uart.output[Uart.len++] = (Uart.shiftReg & 0xff);
317 Uart.parityBits <<= 1; // make room for the new parity bit
318 Uart.parityBits |= ((Uart.shiftReg >> 8) & 0x01); // store parity bit
319 Uart.bitCount = 0;
320 Uart.shiftReg = 0;
321 if ((Uart.len&0x0007) == 0) { // every 8 data bytes
322 Uart.parity[Uart.parityLen++] = Uart.parityBits; // store 8 parity bits
323 Uart.parityBits = 0;
324 }
325 }
326 } else { // no modulation in both halves - Sequence Y
327 if (Uart.state == STATE_MILLER_Z || Uart.state == STATE_MILLER_Y) { // Y after logic "0" - End of Communication
328 Uart.state = STATE_UNSYNCD;
329 Uart.bitCount--; // last "0" was part of EOC sequence
330 Uart.shiftReg <<= 1; // drop it
331 if(Uart.bitCount > 0) { // if we decoded some bits
332 Uart.shiftReg >>= (9 - Uart.bitCount); // right align them
333 Uart.output[Uart.len++] = (Uart.shiftReg & 0xff); // add last byte to the output
334 Uart.parityBits <<= 1; // add a (void) parity bit
335 Uart.parityBits <<= (8 - (Uart.len&0x0007)); // left align parity bits
336 Uart.parity[Uart.parityLen++] = Uart.parityBits; // and store it
337 return TRUE;
338 } else if (Uart.len & 0x0007) { // there are some parity bits to store
339 Uart.parityBits <<= (8 - (Uart.len&0x0007)); // left align remaining parity bits
340 Uart.parity[Uart.parityLen++] = Uart.parityBits; // and store them
341 }
342 if (Uart.len) {
343 return TRUE; // we are finished with decoding the raw data sequence
344 } else {
345 UartReset(); // Nothing received - start over
346 }
347 }
348 if (Uart.state == STATE_START_OF_COMMUNICATION) { // error - must not follow directly after SOC
349 UartReset();
350 } else { // a logic "0"
351 Uart.bitCount++;
352 Uart.shiftReg = (Uart.shiftReg >> 1); // add a 0 to the shiftreg
353 Uart.state = STATE_MILLER_Y;
354 if(Uart.bitCount >= 9) { // if we decoded a full byte (including parity)
355 Uart.output[Uart.len++] = (Uart.shiftReg & 0xff);
356 Uart.parityBits <<= 1; // make room for the parity bit
357 Uart.parityBits |= ((Uart.shiftReg >> 8) & 0x01); // store parity bit
358 Uart.bitCount = 0;
359 Uart.shiftReg = 0;
360 if ((Uart.len&0x0007) == 0) { // every 8 data bytes
361 Uart.parity[Uart.parityLen++] = Uart.parityBits; // store 8 parity bits
362 Uart.parityBits = 0;
363 }
364 }
365 }
366 }
367 }
368
369 }
370
371 return FALSE; // not finished yet, need more data
372 }
373
374
375
376 //=============================================================================
377 // ISO 14443 Type A - Manchester decoder
378 //=============================================================================
379 // Basics:
380 // This decoder is used when the PM3 acts as a reader.
381 // The tag will modulate the reader field by asserting different loads to it. As a consequence, the voltage
382 // at the reader antenna will be modulated as well. The FPGA detects the modulation for us and would deliver e.g. the following:
383 // ........ 0 0 1 1 1 1 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 .......
384 // The Manchester decoder needs to identify the following sequences:
385 // 4 ticks modulated followed by 4 ticks unmodulated: Sequence D = 1 (also used as "start of communication")
386 // 4 ticks unmodulated followed by 4 ticks modulated: Sequence E = 0
387 // 8 ticks unmodulated: Sequence F = end of communication
388 // 8 ticks modulated: A collision. Save the collision position and treat as Sequence D
389 // Note 1: the bitstream may start at any time. We therefore need to sync.
390 // Note 2: parameter offset is used to determine the position of the parity bits (required for the anticollision command only)
391 static tDemod Demod;
392
393 // Lookup-Table to decide if 4 raw bits are a modulation.
394 // We accept three or four "1" in any position
395 const bool Mod_Manchester_LUT[] = {
396 FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, TRUE,
397 FALSE, FALSE, FALSE, TRUE, FALSE, TRUE, TRUE, TRUE
398 };
399
400 #define IsManchesterModulationNibble1(b) (Mod_Manchester_LUT[(b & 0x00F0) >> 4])
401 #define IsManchesterModulationNibble2(b) (Mod_Manchester_LUT[(b & 0x000F)])
402
403
404 void DemodReset()
405 {
406 Demod.state = DEMOD_UNSYNCD;
407 Demod.len = 0; // number of decoded data bytes
408 Demod.parityLen = 0;
409 Demod.shiftReg = 0; // shiftreg to hold decoded data bits
410 Demod.parityBits = 0; //
411 Demod.collisionPos = 0; // Position of collision bit
412 Demod.twoBits = 0xffff; // buffer for 2 Bits
413 Demod.highCnt = 0;
414 Demod.startTime = 0;
415 Demod.endTime = 0;
416 }
417
418 void DemodInit(uint8_t *data, uint8_t *parity)
419 {
420 Demod.output = data;
421 Demod.parity = parity;
422 DemodReset();
423 }
424
425 // use parameter non_real_time to provide a timestamp. Set to 0 if the decoder should measure real time
426 static RAMFUNC int ManchesterDecoding(uint8_t bit, uint16_t offset, uint32_t non_real_time)
427 {
428
429 Demod.twoBits = (Demod.twoBits << 8) | bit;
430
431 if (Demod.state == DEMOD_UNSYNCD) {
432
433 if (Demod.highCnt < 2) { // wait for a stable unmodulated signal
434 if (Demod.twoBits == 0x0000) {
435 Demod.highCnt++;
436 } else {
437 Demod.highCnt = 0;
438 }
439 } else {
440 Demod.syncBit = 0xFFFF; // not set
441 if ((Demod.twoBits & 0x7700) == 0x7000) Demod.syncBit = 7;
442 else if ((Demod.twoBits & 0x3B80) == 0x3800) Demod.syncBit = 6;
443 else if ((Demod.twoBits & 0x1DC0) == 0x1C00) Demod.syncBit = 5;
444 else if ((Demod.twoBits & 0x0EE0) == 0x0E00) Demod.syncBit = 4;
445 else if ((Demod.twoBits & 0x0770) == 0x0700) Demod.syncBit = 3;
446 else if ((Demod.twoBits & 0x03B8) == 0x0380) Demod.syncBit = 2;
447 else if ((Demod.twoBits & 0x01DC) == 0x01C0) Demod.syncBit = 1;
448 else if ((Demod.twoBits & 0x00EE) == 0x00E0) Demod.syncBit = 0;
449 if (Demod.syncBit != 0xFFFF) {
450 Demod.startTime = non_real_time?non_real_time:(GetCountSspClk() & 0xfffffff8);
451 Demod.startTime -= Demod.syncBit;
452 Demod.bitCount = offset; // number of decoded data bits
453 Demod.state = DEMOD_MANCHESTER_DATA;
454 }
455 }
456
457 } else {
458
459 if (IsManchesterModulationNibble1(Demod.twoBits >> Demod.syncBit)) { // modulation in first half
460 if (IsManchesterModulationNibble2(Demod.twoBits >> Demod.syncBit)) { // ... and in second half = collision
461 if (!Demod.collisionPos) {
462 Demod.collisionPos = (Demod.len << 3) + Demod.bitCount;
463 }
464 } // modulation in first half only - Sequence D = 1
465 Demod.bitCount++;
466 Demod.shiftReg = (Demod.shiftReg >> 1) | 0x100; // in both cases, add a 1 to the shiftreg
467 if(Demod.bitCount == 9) { // if we decoded a full byte (including parity)
468 Demod.output[Demod.len++] = (Demod.shiftReg & 0xff);
469 Demod.parityBits <<= 1; // make room for the parity bit
470 Demod.parityBits |= ((Demod.shiftReg >> 8) & 0x01); // store parity bit
471 Demod.bitCount = 0;
472 Demod.shiftReg = 0;
473 if((Demod.len&0x0007) == 0) { // every 8 data bytes
474 Demod.parity[Demod.parityLen++] = Demod.parityBits; // store 8 parity bits
475 Demod.parityBits = 0;
476 }
477 }
478 Demod.endTime = Demod.startTime + 8*(9*Demod.len + Demod.bitCount + 1) - 4;
479 } else { // no modulation in first half
480 if (IsManchesterModulationNibble2(Demod.twoBits >> Demod.syncBit)) { // and modulation in second half = Sequence E = 0
481 Demod.bitCount++;
482 Demod.shiftReg = (Demod.shiftReg >> 1); // add a 0 to the shiftreg
483 if(Demod.bitCount >= 9) { // if we decoded a full byte (including parity)
484 Demod.output[Demod.len++] = (Demod.shiftReg & 0xff);
485 Demod.parityBits <<= 1; // make room for the new parity bit
486 Demod.parityBits |= ((Demod.shiftReg >> 8) & 0x01); // store parity bit
487 Demod.bitCount = 0;
488 Demod.shiftReg = 0;
489 if ((Demod.len&0x0007) == 0) { // every 8 data bytes
490 Demod.parity[Demod.parityLen++] = Demod.parityBits; // store 8 parity bits1
491 Demod.parityBits = 0;
492 }
493 }
494 Demod.endTime = Demod.startTime + 8*(9*Demod.len + Demod.bitCount + 1);
495 } else { // no modulation in both halves - End of communication
496 if(Demod.bitCount > 0) { // there are some remaining data bits
497 Demod.shiftReg >>= (9 - Demod.bitCount); // right align the decoded bits
498 Demod.output[Demod.len++] = Demod.shiftReg & 0xff; // and add them to the output
499 Demod.parityBits <<= 1; // add a (void) parity bit
500 Demod.parityBits <<= (8 - (Demod.len&0x0007)); // left align remaining parity bits
501 Demod.parity[Demod.parityLen++] = Demod.parityBits; // and store them
502 return TRUE;
503 } else if (Demod.len & 0x0007) { // there are some parity bits to store
504 Demod.parityBits <<= (8 - (Demod.len&0x0007)); // left align remaining parity bits
505 Demod.parity[Demod.parityLen++] = Demod.parityBits; // and store them
506 }
507 if (Demod.len) {
508 return TRUE; // we are finished with decoding the raw data sequence
509 } else { // nothing received. Start over
510 DemodReset();
511 }
512 }
513 }
514
515 }
516
517 return FALSE; // not finished yet, need more data
518 }
519
520 //=============================================================================
521 // Finally, a `sniffer' for ISO 14443 Type A
522 // Both sides of communication!
523 //=============================================================================
524
525 //-----------------------------------------------------------------------------
526 // Record the sequence of commands sent by the reader to the tag, with
527 // triggering so that we start recording at the point that the tag is moved
528 // near the reader.
529 //-----------------------------------------------------------------------------
530 void RAMFUNC SnoopIso14443a(uint8_t param) {
531 // param:
532 // bit 0 - trigger from first card answer
533 // bit 1 - trigger from first reader 7-bit request
534
535 LEDsoff();
536
537 iso14443a_setup(FPGA_HF_ISO14443A_SNIFFER);
538
539 // Allocate memory from BigBuf for some buffers
540 // free all previous allocations first
541 BigBuf_free();
542
543 // The command (reader -> tag) that we're receiving.
544 uint8_t *receivedCmd = BigBuf_malloc(MAX_FRAME_SIZE);
545 uint8_t *receivedCmdPar = BigBuf_malloc(MAX_PARITY_SIZE);
546
547 // The response (tag -> reader) that we're receiving.
548 uint8_t *receivedResponse = BigBuf_malloc(MAX_FRAME_SIZE);
549 uint8_t *receivedResponsePar = BigBuf_malloc(MAX_PARITY_SIZE);
550
551 // The DMA buffer, used to stream samples from the FPGA
552 uint8_t *dmaBuf = BigBuf_malloc(DMA_BUFFER_SIZE);
553
554 // init trace buffer
555 clear_trace();
556 set_tracing(TRUE);
557
558 uint8_t *data = dmaBuf;
559 uint8_t previous_data = 0;
560 int maxDataLen = 0;
561 int dataLen = 0;
562 bool TagIsActive = FALSE;
563 bool ReaderIsActive = FALSE;
564
565 // Set up the demodulator for tag -> reader responses.
566 DemodInit(receivedResponse, receivedResponsePar);
567
568 // Set up the demodulator for the reader -> tag commands
569 UartInit(receivedCmd, receivedCmdPar);
570
571 // Setup and start DMA.
572 FpgaSetupSscDma((uint8_t *)dmaBuf, DMA_BUFFER_SIZE);
573
574 // We won't start recording the frames that we acquire until we trigger;
575 // a good trigger condition to get started is probably when we see a
576 // response from the tag.
577 // triggered == FALSE -- to wait first for card
578 bool triggered = !(param & 0x03);
579
580 // And now we loop, receiving samples.
581 for(uint32_t rsamples = 0; TRUE; ) {
582
583 if(BUTTON_PRESS()) {
584 DbpString("cancelled by button");
585 break;
586 }
587
588 LED_A_ON();
589 WDT_HIT();
590
591 int register readBufDataP = data - dmaBuf;
592 int register dmaBufDataP = DMA_BUFFER_SIZE - AT91C_BASE_PDC_SSC->PDC_RCR;
593 if (readBufDataP <= dmaBufDataP){
594 dataLen = dmaBufDataP - readBufDataP;
595 } else {
596 dataLen = DMA_BUFFER_SIZE - readBufDataP + dmaBufDataP;
597 }
598 // test for length of buffer
599 if(dataLen > maxDataLen) {
600 maxDataLen = dataLen;
601 if(dataLen > (9 * DMA_BUFFER_SIZE / 10)) {
602 Dbprintf("blew circular buffer! dataLen=%d", dataLen);
603 break;
604 }
605 }
606 if(dataLen < 1) continue;
607
608 // primary buffer was stopped( <-- we lost data!
609 if (!AT91C_BASE_PDC_SSC->PDC_RCR) {
610 AT91C_BASE_PDC_SSC->PDC_RPR = (uint32_t) dmaBuf;
611 AT91C_BASE_PDC_SSC->PDC_RCR = DMA_BUFFER_SIZE;
612 Dbprintf("RxEmpty ERROR!!! data length:%d", dataLen); // temporary
613 }
614 // secondary buffer sets as primary, secondary buffer was stopped
615 if (!AT91C_BASE_PDC_SSC->PDC_RNCR) {
616 AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) dmaBuf;
617 AT91C_BASE_PDC_SSC->PDC_RNCR = DMA_BUFFER_SIZE;
618 }
619
620 LED_A_OFF();
621
622 if (rsamples & 0x01) { // Need two samples to feed Miller and Manchester-Decoder
623
624 if(!TagIsActive) { // no need to try decoding reader data if the tag is sending
625 uint8_t readerdata = (previous_data & 0xF0) | (*data >> 4);
626 if (MillerDecoding(readerdata, (rsamples-1)*4)) {
627 LED_C_ON();
628
629 // check - if there is a short 7bit request from reader
630 if ((!triggered) && (param & 0x02) && (Uart.len == 1) && (Uart.bitCount == 7)) triggered = TRUE;
631
632 if(triggered) {
633 if (!LogTrace(receivedCmd,
634 Uart.len,
635 Uart.startTime*16 - DELAY_READER_AIR2ARM_AS_SNIFFER,
636 Uart.endTime*16 - DELAY_READER_AIR2ARM_AS_SNIFFER,
637 Uart.parity,
638 TRUE)) break;
639 }
640 /* And ready to receive another command. */
641 UartReset();
642 /* And also reset the demod code, which might have been */
643 /* false-triggered by the commands from the reader. */
644 DemodReset();
645 LED_B_OFF();
646 }
647 ReaderIsActive = (Uart.state != STATE_UNSYNCD);
648 }
649
650 if(!ReaderIsActive) { // no need to try decoding tag data if the reader is sending - and we cannot afford the time
651 uint8_t tagdata = (previous_data << 4) | (*data & 0x0F);
652 if(ManchesterDecoding(tagdata, 0, (rsamples-1)*4)) {
653 LED_B_ON();
654
655 if (!LogTrace(receivedResponse,
656 Demod.len,
657 Demod.startTime*16 - DELAY_TAG_AIR2ARM_AS_SNIFFER,
658 Demod.endTime*16 - DELAY_TAG_AIR2ARM_AS_SNIFFER,
659 Demod.parity,
660 FALSE)) break;
661
662 if ((!triggered) && (param & 0x01)) triggered = TRUE;
663
664 // And ready to receive another response.
665 DemodReset();
666 // And reset the Miller decoder including itS (now outdated) input buffer
667 UartInit(receivedCmd, receivedCmdPar);
668
669 LED_C_OFF();
670 }
671 TagIsActive = (Demod.state != DEMOD_UNSYNCD);
672 }
673 }
674
675 previous_data = *data;
676 rsamples++;
677 data++;
678 if(data == dmaBuf + DMA_BUFFER_SIZE) {
679 data = dmaBuf;
680 }
681 } // main cycle
682
683 DbpString("COMMAND FINISHED");
684
685 FpgaDisableSscDma();
686 Dbprintf("maxDataLen=%d, Uart.state=%x, Uart.len=%d", maxDataLen, Uart.state, Uart.len);
687 Dbprintf("traceLen=%d, Uart.output[0]=%08x", BigBuf_get_traceLen(), (uint32_t)Uart.output[0]);
688 LEDsoff();
689 }
690
691 //-----------------------------------------------------------------------------
692 // Prepare tag messages
693 //-----------------------------------------------------------------------------
694 static void CodeIso14443aAsTagPar(const uint8_t *cmd, uint16_t len, uint8_t *parity)
695 {
696 ToSendReset();
697
698 // Correction bit, might be removed when not needed
699 ToSendStuffBit(0);
700 ToSendStuffBit(0);
701 ToSendStuffBit(0);
702 ToSendStuffBit(0);
703 ToSendStuffBit(1); // 1
704 ToSendStuffBit(0);
705 ToSendStuffBit(0);
706 ToSendStuffBit(0);
707
708 // Send startbit
709 ToSend[++ToSendMax] = SEC_D;
710 LastProxToAirDuration = 8 * ToSendMax - 4;
711
712 for(uint16_t i = 0; i < len; i++) {
713 uint8_t b = cmd[i];
714
715 // Data bits
716 for(uint16_t j = 0; j < 8; j++) {
717 if(b & 1) {
718 ToSend[++ToSendMax] = SEC_D;
719 } else {
720 ToSend[++ToSendMax] = SEC_E;
721 }
722 b >>= 1;
723 }
724
725 // Get the parity bit
726 if (parity[i>>3] & (0x80>>(i&0x0007))) {
727 ToSend[++ToSendMax] = SEC_D;
728 LastProxToAirDuration = 8 * ToSendMax - 4;
729 } else {
730 ToSend[++ToSendMax] = SEC_E;
731 LastProxToAirDuration = 8 * ToSendMax;
732 }
733 }
734
735 // Send stopbit
736 ToSend[++ToSendMax] = SEC_F;
737
738 // Convert from last byte pos to length
739 ToSendMax++;
740 }
741
742 static void CodeIso14443aAsTag(const uint8_t *cmd, uint16_t len)
743 {
744 uint8_t par[MAX_PARITY_SIZE];
745
746 GetParity(cmd, len, par);
747 CodeIso14443aAsTagPar(cmd, len, par);
748 }
749
750
751 static void Code4bitAnswerAsTag(uint8_t cmd)
752 {
753 int i;
754
755 ToSendReset();
756
757 // Correction bit, might be removed when not needed
758 ToSendStuffBit(0);
759 ToSendStuffBit(0);
760 ToSendStuffBit(0);
761 ToSendStuffBit(0);
762 ToSendStuffBit(1); // 1
763 ToSendStuffBit(0);
764 ToSendStuffBit(0);
765 ToSendStuffBit(0);
766
767 // Send startbit
768 ToSend[++ToSendMax] = SEC_D;
769
770 uint8_t b = cmd;
771 for(i = 0; i < 4; i++) {
772 if(b & 1) {
773 ToSend[++ToSendMax] = SEC_D;
774 LastProxToAirDuration = 8 * ToSendMax - 4;
775 } else {
776 ToSend[++ToSendMax] = SEC_E;
777 LastProxToAirDuration = 8 * ToSendMax;
778 }
779 b >>= 1;
780 }
781
782 // Send stopbit
783 ToSend[++ToSendMax] = SEC_F;
784
785 // Convert from last byte pos to length
786 ToSendMax++;
787 }
788
789 //-----------------------------------------------------------------------------
790 // Wait for commands from reader
791 // Stop when button is pressed
792 // Or return TRUE when command is captured
793 //-----------------------------------------------------------------------------
794 static int GetIso14443aCommandFromReader(uint8_t *received, uint8_t *parity, int *len)
795 {
796 // Set FPGA mode to "simulated ISO 14443 tag", no modulation (listen
797 // only, since we are receiving, not transmitting).
798 // Signal field is off with the appropriate LED
799 LED_D_OFF();
800 FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_TAGSIM_LISTEN);
801
802 // Now run a `software UART' on the stream of incoming samples.
803 UartInit(received, parity);
804
805 // clear RXRDY:
806 uint8_t b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
807
808 for(;;) {
809 WDT_HIT();
810
811 if(BUTTON_PRESS()) return FALSE;
812
813 if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
814 b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
815 if(MillerDecoding(b, 0)) {
816 *len = Uart.len;
817 return TRUE;
818 }
819 }
820 }
821 }
822
823 static int EmSendCmd14443aRaw(uint8_t *resp, uint16_t respLen, bool correctionNeeded);
824 int EmSend4bitEx(uint8_t resp, bool correctionNeeded);
825 int EmSend4bit(uint8_t resp);
826 int EmSendCmdExPar(uint8_t *resp, uint16_t respLen, bool correctionNeeded, uint8_t *par);
827 int EmSendCmdEx(uint8_t *resp, uint16_t respLen, bool correctionNeeded);
828 int EmSendCmd(uint8_t *resp, uint16_t respLen);
829 int EmSendCmdPar(uint8_t *resp, uint16_t respLen, uint8_t *par);
830 bool EmLogTrace(uint8_t *reader_data, uint16_t reader_len, uint32_t reader_StartTime, uint32_t reader_EndTime, uint8_t *reader_Parity,
831 uint8_t *tag_data, uint16_t tag_len, uint32_t tag_StartTime, uint32_t tag_EndTime, uint8_t *tag_Parity);
832
833 static uint8_t* free_buffer_pointer;
834
835 typedef struct {
836 uint8_t* response;
837 size_t response_n;
838 uint8_t* modulation;
839 size_t modulation_n;
840 uint32_t ProxToAirDuration;
841 } tag_response_info_t;
842
843 bool prepare_tag_modulation(tag_response_info_t* response_info, size_t max_buffer_size) {
844 // Example response, answer to MIFARE Classic read block will be 16 bytes + 2 CRC = 18 bytes
845 // This will need the following byte array for a modulation sequence
846 // 144 data bits (18 * 8)
847 // 18 parity bits
848 // 2 Start and stop
849 // 1 Correction bit (Answer in 1172 or 1236 periods, see FPGA)
850 // 1 just for the case
851 // ----------- +
852 // 166 bytes, since every bit that needs to be send costs us a byte
853 //
854
855
856 // Prepare the tag modulation bits from the message
857 CodeIso14443aAsTag(response_info->response,response_info->response_n);
858
859 // Make sure we do not exceed the free buffer space
860 if (ToSendMax > max_buffer_size) {
861 Dbprintf("Out of memory, when modulating bits for tag answer:");
862 Dbhexdump(response_info->response_n,response_info->response,false);
863 return false;
864 }
865
866 // Copy the byte array, used for this modulation to the buffer position
867 memcpy(response_info->modulation,ToSend,ToSendMax);
868
869 // Store the number of bytes that were used for encoding/modulation and the time needed to transfer them
870 response_info->modulation_n = ToSendMax;
871 response_info->ProxToAirDuration = LastProxToAirDuration;
872
873 return true;
874 }
875
876
877 // "precompile" responses. There are 7 predefined responses with a total of 28 bytes data to transmit.
878 // Coded responses need one byte per bit to transfer (data, parity, start, stop, correction)
879 // 28 * 8 data bits, 28 * 1 parity bits, 7 start bits, 7 stop bits, 7 correction bits
880 // -> need 273 bytes buffer
881 #define ALLOCATED_TAG_MODULATION_BUFFER_SIZE 273
882
883 bool prepare_allocated_tag_modulation(tag_response_info_t* response_info) {
884 // Retrieve and store the current buffer index
885 response_info->modulation = free_buffer_pointer;
886
887 // Determine the maximum size we can use from our buffer
888 size_t max_buffer_size = ALLOCATED_TAG_MODULATION_BUFFER_SIZE;
889
890 // Forward the prepare tag modulation function to the inner function
891 if (prepare_tag_modulation(response_info, max_buffer_size)) {
892 // Update the free buffer offset
893 free_buffer_pointer += ToSendMax;
894 return true;
895 } else {
896 return false;
897 }
898 }
899
900 //-----------------------------------------------------------------------------
901 // Main loop of simulated tag: receive commands from reader, decide what
902 // response to send, and send it.
903 //-----------------------------------------------------------------------------
904 void SimulateIso14443aTag(int tagType, int uid_1st, int uid_2nd, byte_t* data)
905 {
906 uint8_t sak;
907
908 // The first response contains the ATQA (note: bytes are transmitted in reverse order).
909 uint8_t response1[2];
910
911 switch (tagType) {
912 case 1: { // MIFARE Classic
913 // Says: I am Mifare 1k - original line
914 response1[0] = 0x04;
915 response1[1] = 0x00;
916 sak = 0x08;
917 } break;
918 case 2: { // MIFARE Ultralight
919 // Says: I am a stupid memory tag, no crypto
920 response1[0] = 0x04;
921 response1[1] = 0x00;
922 sak = 0x00;
923 } break;
924 case 3: { // MIFARE DESFire
925 // Says: I am a DESFire tag, ph33r me
926 response1[0] = 0x04;
927 response1[1] = 0x03;
928 sak = 0x20;
929 } break;
930 case 4: { // ISO/IEC 14443-4
931 // Says: I am a javacard (JCOP)
932 response1[0] = 0x04;
933 response1[1] = 0x00;
934 sak = 0x28;
935 } break;
936 case 5: { // MIFARE TNP3XXX
937 // Says: I am a toy
938 response1[0] = 0x01;
939 response1[1] = 0x0f;
940 sak = 0x01;
941 } break;
942 default: {
943 Dbprintf("Error: unkown tagtype (%d)",tagType);
944 return;
945 } break;
946 }
947
948 // The second response contains the (mandatory) first 24 bits of the UID
949 uint8_t response2[5] = {0x00};
950
951 // Check if the uid uses the (optional) part
952 uint8_t response2a[5] = {0x00};
953
954 if (uid_2nd) {
955 response2[0] = 0x88;
956 num_to_bytes(uid_1st,3,response2+1);
957 num_to_bytes(uid_2nd,4,response2a);
958 response2a[4] = response2a[0] ^ response2a[1] ^ response2a[2] ^ response2a[3];
959
960 // Configure the ATQA and SAK accordingly
961 response1[0] |= 0x40;
962 sak |= 0x04;
963 } else {
964 num_to_bytes(uid_1st,4,response2);
965 // Configure the ATQA and SAK accordingly
966 response1[0] &= 0xBF;
967 sak &= 0xFB;
968 }
969
970 // Calculate the BitCountCheck (BCC) for the first 4 bytes of the UID.
971 response2[4] = response2[0] ^ response2[1] ^ response2[2] ^ response2[3];
972
973 // Prepare the mandatory SAK (for 4 and 7 byte UID)
974 uint8_t response3[3] = {0x00};
975 response3[0] = sak;
976 ComputeCrc14443(CRC_14443_A, response3, 1, &response3[1], &response3[2]);
977
978 // Prepare the optional second SAK (for 7 byte UID), drop the cascade bit
979 uint8_t response3a[3] = {0x00};
980 response3a[0] = sak & 0xFB;
981 ComputeCrc14443(CRC_14443_A, response3a, 1, &response3a[1], &response3a[2]);
982
983 uint8_t response5[] = { 0x00, 0x00, 0x00, 0x00 }; // Very random tag nonce
984 uint8_t response6[] = { 0x04, 0x58, 0x80, 0x02, 0x00, 0x00 }; // dummy ATS (pseudo-ATR), answer to RATS:
985 // Format byte = 0x58: FSCI=0x08 (FSC=256), TA(1) and TC(1) present,
986 // TA(1) = 0x80: different divisors not supported, DR = 1, DS = 1
987 // TB(1) = not present. Defaults: FWI = 4 (FWT = 256 * 16 * 2^4 * 1/fc = 4833us), SFGI = 0 (SFG = 256 * 16 * 2^0 * 1/fc = 302us)
988 // TC(1) = 0x02: CID supported, NAD not supported
989 ComputeCrc14443(CRC_14443_A, response6, 4, &response6[4], &response6[5]);
990
991 #define TAG_RESPONSE_COUNT 7
992 tag_response_info_t responses[TAG_RESPONSE_COUNT] = {
993 { .response = response1, .response_n = sizeof(response1) }, // Answer to request - respond with card type
994 { .response = response2, .response_n = sizeof(response2) }, // Anticollision cascade1 - respond with uid
995 { .response = response2a, .response_n = sizeof(response2a) }, // Anticollision cascade2 - respond with 2nd half of uid if asked
996 { .response = response3, .response_n = sizeof(response3) }, // Acknowledge select - cascade 1
997 { .response = response3a, .response_n = sizeof(response3a) }, // Acknowledge select - cascade 2
998 { .response = response5, .response_n = sizeof(response5) }, // Authentication answer (random nonce)
999 { .response = response6, .response_n = sizeof(response6) }, // dummy ATS (pseudo-ATR), answer to RATS
1000 };
1001
1002 // Allocate 512 bytes for the dynamic modulation, created when the reader queries for it
1003 // Such a response is less time critical, so we can prepare them on the fly
1004 #define DYNAMIC_RESPONSE_BUFFER_SIZE 64
1005 #define DYNAMIC_MODULATION_BUFFER_SIZE 512
1006 uint8_t dynamic_response_buffer[DYNAMIC_RESPONSE_BUFFER_SIZE];
1007 uint8_t dynamic_modulation_buffer[DYNAMIC_MODULATION_BUFFER_SIZE];
1008 tag_response_info_t dynamic_response_info = {
1009 .response = dynamic_response_buffer,
1010 .response_n = 0,
1011 .modulation = dynamic_modulation_buffer,
1012 .modulation_n = 0
1013 };
1014
1015 // We need to listen to the high-frequency, peak-detected path.
1016 iso14443a_setup(FPGA_HF_ISO14443A_TAGSIM_LISTEN);
1017
1018 BigBuf_free_keep_EM();
1019
1020 // allocate buffers:
1021 uint8_t *receivedCmd = BigBuf_malloc(MAX_FRAME_SIZE);
1022 uint8_t *receivedCmdPar = BigBuf_malloc(MAX_PARITY_SIZE);
1023 free_buffer_pointer = BigBuf_malloc(ALLOCATED_TAG_MODULATION_BUFFER_SIZE);
1024
1025 // clear trace
1026 clear_trace();
1027 set_tracing(TRUE);
1028
1029 // Prepare the responses of the anticollision phase
1030 // there will be not enough time to do this at the moment the reader sends it REQA
1031 for (size_t i=0; i<TAG_RESPONSE_COUNT; i++) {
1032 prepare_allocated_tag_modulation(&responses[i]);
1033 }
1034
1035 int len = 0;
1036
1037 // To control where we are in the protocol
1038 int order = 0;
1039 int lastorder;
1040
1041 // Just to allow some checks
1042 int happened = 0;
1043 int happened2 = 0;
1044 int cmdsRecvd = 0;
1045
1046 cmdsRecvd = 0;
1047 tag_response_info_t* p_response;
1048
1049 LED_A_ON();
1050 for(;;) {
1051 // Clean receive command buffer
1052 if(!GetIso14443aCommandFromReader(receivedCmd, receivedCmdPar, &len)) {
1053 DbpString("Button press");
1054 break;
1055 }
1056
1057 p_response = NULL;
1058
1059 // Okay, look at the command now.
1060 lastorder = order;
1061 if(receivedCmd[0] == 0x26) { // Received a REQUEST
1062 p_response = &responses[0]; order = 1;
1063 } else if(receivedCmd[0] == 0x52) { // Received a WAKEUP
1064 p_response = &responses[0]; order = 6;
1065 } else if(receivedCmd[1] == 0x20 && receivedCmd[0] == 0x93) { // Received request for UID (cascade 1)
1066 p_response = &responses[1]; order = 2;
1067 } else if(receivedCmd[1] == 0x20 && receivedCmd[0] == 0x95) { // Received request for UID (cascade 2)
1068 p_response = &responses[2]; order = 20;
1069 } else if(receivedCmd[1] == 0x70 && receivedCmd[0] == 0x93) { // Received a SELECT (cascade 1)
1070 p_response = &responses[3]; order = 3;
1071 } else if(receivedCmd[1] == 0x70 && receivedCmd[0] == 0x95) { // Received a SELECT (cascade 2)
1072 p_response = &responses[4]; order = 30;
1073 } else if(receivedCmd[0] == 0x30) { // Received a (plain) READ
1074 EmSendCmdEx(data+(4*receivedCmd[1]),16,false);
1075 // Dbprintf("Read request from reader: %x %x",receivedCmd[0],receivedCmd[1]);
1076 // We already responded, do not send anything with the EmSendCmd14443aRaw() that is called below
1077 p_response = NULL;
1078 } else if(receivedCmd[0] == 0x50) { // Received a HALT
1079
1080 if (tracing) {
1081 LogTrace(receivedCmd, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parity, TRUE);
1082 }
1083 p_response = NULL;
1084 } else if(receivedCmd[0] == 0x60 || receivedCmd[0] == 0x61) { // Received an authentication request
1085 p_response = &responses[5]; order = 7;
1086 } else if(receivedCmd[0] == 0xE0) { // Received a RATS request
1087 if (tagType == 1 || tagType == 2) { // RATS not supported
1088 EmSend4bit(CARD_NACK_NA);
1089 p_response = NULL;
1090 } else {
1091 p_response = &responses[6]; order = 70;
1092 }
1093 } else if (order == 7 && len == 8) { // Received {nr] and {ar} (part of authentication)
1094 if (tracing) {
1095 LogTrace(receivedCmd, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parity, TRUE);
1096 }
1097 uint32_t nr = bytes_to_num(receivedCmd,4);
1098 uint32_t ar = bytes_to_num(receivedCmd+4,4);
1099 Dbprintf("Auth attempt {nr}{ar}: %08x %08x",nr,ar);
1100 } else {
1101 // Check for ISO 14443A-4 compliant commands, look at left nibble
1102 switch (receivedCmd[0]) {
1103
1104 case 0x0B:
1105 case 0x0A: { // IBlock (command)
1106 dynamic_response_info.response[0] = receivedCmd[0];
1107 dynamic_response_info.response[1] = 0x00;
1108 dynamic_response_info.response[2] = 0x90;
1109 dynamic_response_info.response[3] = 0x00;
1110 dynamic_response_info.response_n = 4;
1111 } break;
1112
1113 case 0x1A:
1114 case 0x1B: { // Chaining command
1115 dynamic_response_info.response[0] = 0xaa | ((receivedCmd[0]) & 1);
1116 dynamic_response_info.response_n = 2;
1117 } break;
1118
1119 case 0xaa:
1120 case 0xbb: {
1121 dynamic_response_info.response[0] = receivedCmd[0] ^ 0x11;
1122 dynamic_response_info.response_n = 2;
1123 } break;
1124
1125 case 0xBA: { //
1126 memcpy(dynamic_response_info.response,"\xAB\x00",2);
1127 dynamic_response_info.response_n = 2;
1128 } break;
1129
1130 case 0xCA:
1131 case 0xC2: { // Readers sends deselect command
1132 memcpy(dynamic_response_info.response,"\xCA\x00",2);
1133 dynamic_response_info.response_n = 2;
1134 } break;
1135
1136 default: {
1137 // Never seen this command before
1138 if (tracing) {
1139 LogTrace(receivedCmd, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parity, TRUE);
1140 }
1141 Dbprintf("Received unknown command (len=%d):",len);
1142 Dbhexdump(len,receivedCmd,false);
1143 // Do not respond
1144 dynamic_response_info.response_n = 0;
1145 } break;
1146 }
1147
1148 if (dynamic_response_info.response_n > 0) {
1149 // Copy the CID from the reader query
1150 dynamic_response_info.response[1] = receivedCmd[1];
1151
1152 // Add CRC bytes, always used in ISO 14443A-4 compliant cards
1153 AppendCrc14443a(dynamic_response_info.response,dynamic_response_info.response_n);
1154 dynamic_response_info.response_n += 2;
1155
1156 if (prepare_tag_modulation(&dynamic_response_info,DYNAMIC_MODULATION_BUFFER_SIZE) == false) {
1157 Dbprintf("Error preparing tag response");
1158 if (tracing) {
1159 LogTrace(receivedCmd, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parity, TRUE);
1160 }
1161 break;
1162 }
1163 p_response = &dynamic_response_info;
1164 }
1165 }
1166
1167 // Count number of wakeups received after a halt
1168 if(order == 6 && lastorder == 5) { happened++; }
1169
1170 // Count number of other messages after a halt
1171 if(order != 6 && lastorder == 5) { happened2++; }
1172
1173 if(cmdsRecvd > 999) {
1174 DbpString("1000 commands later...");
1175 break;
1176 }
1177 cmdsRecvd++;
1178
1179 if (p_response != NULL) {
1180 EmSendCmd14443aRaw(p_response->modulation, p_response->modulation_n, receivedCmd[0] == 0x52);
1181 // do the tracing for the previous reader request and this tag answer:
1182 uint8_t par[MAX_PARITY_SIZE];
1183 GetParity(p_response->response, p_response->response_n, par);
1184
1185 EmLogTrace(Uart.output,
1186 Uart.len,
1187 Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG,
1188 Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG,
1189 Uart.parity,
1190 p_response->response,
1191 p_response->response_n,
1192 LastTimeProxToAirStart*16 + DELAY_ARM2AIR_AS_TAG,
1193 (LastTimeProxToAirStart + p_response->ProxToAirDuration)*16 + DELAY_ARM2AIR_AS_TAG,
1194 par);
1195 }
1196
1197 if (!tracing) {
1198 Dbprintf("Trace Full. Simulation stopped.");
1199 break;
1200 }
1201 }
1202
1203 Dbprintf("%x %x %x", happened, happened2, cmdsRecvd);
1204 LED_A_OFF();
1205 BigBuf_free_keep_EM();
1206 }
1207
1208
1209 // prepare a delayed transfer. This simply shifts ToSend[] by a number
1210 // of bits specified in the delay parameter.
1211 void PrepareDelayedTransfer(uint16_t delay)
1212 {
1213 uint8_t bitmask = 0;
1214 uint8_t bits_to_shift = 0;
1215 uint8_t bits_shifted = 0;
1216
1217 delay &= 0x07;
1218 if (delay) {
1219 for (uint16_t i = 0; i < delay; i++) {
1220 bitmask |= (0x01 << i);
1221 }
1222 ToSend[ToSendMax++] = 0x00;
1223 for (uint16_t i = 0; i < ToSendMax; i++) {
1224 bits_to_shift = ToSend[i] & bitmask;
1225 ToSend[i] = ToSend[i] >> delay;
1226 ToSend[i] = ToSend[i] | (bits_shifted << (8 - delay));
1227 bits_shifted = bits_to_shift;
1228 }
1229 }
1230 }
1231
1232
1233 //-------------------------------------------------------------------------------------
1234 // Transmit the command (to the tag) that was placed in ToSend[].
1235 // Parameter timing:
1236 // if NULL: transfer at next possible time, taking into account
1237 // request guard time and frame delay time
1238 // if == 0: transfer immediately and return time of transfer
1239 // if != 0: delay transfer until time specified
1240 //-------------------------------------------------------------------------------------
1241 static void TransmitFor14443a(const uint8_t *cmd, uint16_t len, uint32_t *timing)
1242 {
1243
1244 FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_READER_MOD);
1245
1246 uint32_t ThisTransferTime = 0;
1247
1248 if (timing) {
1249 if(*timing == 0) { // Measure time
1250 *timing = (GetCountSspClk() + 8) & 0xfffffff8;
1251 } else {
1252 PrepareDelayedTransfer(*timing & 0x00000007); // Delay transfer (fine tuning - up to 7 MF clock ticks)
1253 }
1254 if(MF_DBGLEVEL >= 4 && GetCountSspClk() >= (*timing & 0xfffffff8)) Dbprintf("TransmitFor14443a: Missed timing");
1255 while(GetCountSspClk() < (*timing & 0xfffffff8)); // Delay transfer (multiple of 8 MF clock ticks)
1256 LastTimeProxToAirStart = *timing;
1257 } else {
1258 ThisTransferTime = ((MAX(NextTransferTime, GetCountSspClk()) & 0xfffffff8) + 8);
1259 while(GetCountSspClk() < ThisTransferTime);
1260 LastTimeProxToAirStart = ThisTransferTime;
1261 }
1262
1263 // clear TXRDY
1264 AT91C_BASE_SSC->SSC_THR = SEC_Y;
1265
1266 uint16_t c = 0;
1267 for(;;) {
1268 if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
1269 AT91C_BASE_SSC->SSC_THR = cmd[c];
1270 c++;
1271 if(c >= len) {
1272 break;
1273 }
1274 }
1275 }
1276
1277 NextTransferTime = MAX(NextTransferTime, LastTimeProxToAirStart + REQUEST_GUARD_TIME);
1278 }
1279
1280
1281 //-----------------------------------------------------------------------------
1282 // Prepare reader command (in bits, support short frames) to send to FPGA
1283 //-----------------------------------------------------------------------------
1284 void CodeIso14443aBitsAsReaderPar(const uint8_t *cmd, uint16_t bits, const uint8_t *parity)
1285 {
1286 int i, j;
1287 int last;
1288 uint8_t b;
1289
1290 ToSendReset();
1291
1292 // Start of Communication (Seq. Z)
1293 ToSend[++ToSendMax] = SEC_Z;
1294 LastProxToAirDuration = 8 * (ToSendMax+1) - 6;
1295 last = 0;
1296
1297 size_t bytecount = nbytes(bits);
1298 // Generate send structure for the data bits
1299 for (i = 0; i < bytecount; i++) {
1300 // Get the current byte to send
1301 b = cmd[i];
1302 size_t bitsleft = MIN((bits-(i*8)),8);
1303
1304 for (j = 0; j < bitsleft; j++) {
1305 if (b & 1) {
1306 // Sequence X
1307 ToSend[++ToSendMax] = SEC_X;
1308 LastProxToAirDuration = 8 * (ToSendMax+1) - 2;
1309 last = 1;
1310 } else {
1311 if (last == 0) {
1312 // Sequence Z
1313 ToSend[++ToSendMax] = SEC_Z;
1314 LastProxToAirDuration = 8 * (ToSendMax+1) - 6;
1315 } else {
1316 // Sequence Y
1317 ToSend[++ToSendMax] = SEC_Y;
1318 last = 0;
1319 }
1320 }
1321 b >>= 1;
1322 }
1323
1324 // Only transmit parity bit if we transmitted a complete byte
1325 if (j == 8 && parity != NULL) {
1326 // Get the parity bit
1327 if (parity[i>>3] & (0x80 >> (i&0x0007))) {
1328 // Sequence X
1329 ToSend[++ToSendMax] = SEC_X;
1330 LastProxToAirDuration = 8 * (ToSendMax+1) - 2;
1331 last = 1;
1332 } else {
1333 if (last == 0) {
1334 // Sequence Z
1335 ToSend[++ToSendMax] = SEC_Z;
1336 LastProxToAirDuration = 8 * (ToSendMax+1) - 6;
1337 } else {
1338 // Sequence Y
1339 ToSend[++ToSendMax] = SEC_Y;
1340 last = 0;
1341 }
1342 }
1343 }
1344 }
1345
1346 // End of Communication: Logic 0 followed by Sequence Y
1347 if (last == 0) {
1348 // Sequence Z
1349 ToSend[++ToSendMax] = SEC_Z;
1350 LastProxToAirDuration = 8 * (ToSendMax+1) - 6;
1351 } else {
1352 // Sequence Y
1353 ToSend[++ToSendMax] = SEC_Y;
1354 last = 0;
1355 }
1356 ToSend[++ToSendMax] = SEC_Y;
1357
1358 // Convert to length of command:
1359 ToSendMax++;
1360 }
1361
1362 //-----------------------------------------------------------------------------
1363 // Prepare reader command to send to FPGA
1364 //-----------------------------------------------------------------------------
1365 void CodeIso14443aAsReaderPar(const uint8_t *cmd, uint16_t len, const uint8_t *parity)
1366 {
1367 CodeIso14443aBitsAsReaderPar(cmd, len*8, parity);
1368 }
1369
1370
1371 //-----------------------------------------------------------------------------
1372 // Wait for commands from reader
1373 // Stop when button is pressed (return 1) or field was gone (return 2)
1374 // Or return 0 when command is captured
1375 //-----------------------------------------------------------------------------
1376 static int EmGetCmd(uint8_t *received, uint16_t *len, uint8_t *parity)
1377 {
1378 *len = 0;
1379
1380 uint32_t timer = 0, vtime = 0;
1381 int analogCnt = 0;
1382 int analogAVG = 0;
1383
1384 // Set FPGA mode to "simulated ISO 14443 tag", no modulation (listen
1385 // only, since we are receiving, not transmitting).
1386 // Signal field is off with the appropriate LED
1387 LED_D_OFF();
1388 FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_TAGSIM_LISTEN);
1389
1390 // Set ADC to read field strength
1391 AT91C_BASE_ADC->ADC_CR = AT91C_ADC_SWRST;
1392 AT91C_BASE_ADC->ADC_MR =
1393 ADC_MODE_PRESCALE(63) |
1394 ADC_MODE_STARTUP_TIME(1) |
1395 ADC_MODE_SAMPLE_HOLD_TIME(15);
1396 AT91C_BASE_ADC->ADC_CHER = ADC_CHANNEL(ADC_CHAN_HF);
1397 // start ADC
1398 AT91C_BASE_ADC->ADC_CR = AT91C_ADC_START;
1399
1400 // Now run a 'software UART' on the stream of incoming samples.
1401 UartInit(received, parity);
1402
1403 // Clear RXRDY:
1404 uint8_t b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
1405
1406 for(;;) {
1407 WDT_HIT();
1408
1409 if (BUTTON_PRESS()) return 1;
1410
1411 // test if the field exists
1412 if (AT91C_BASE_ADC->ADC_SR & ADC_END_OF_CONVERSION(ADC_CHAN_HF)) {
1413 analogCnt++;
1414 analogAVG += AT91C_BASE_ADC->ADC_CDR[ADC_CHAN_HF];
1415 AT91C_BASE_ADC->ADC_CR = AT91C_ADC_START;
1416 if (analogCnt >= 32) {
1417 if ((MAX_ADC_HF_VOLTAGE * (analogAVG / analogCnt) >> 10) < MF_MINFIELDV) {
1418 vtime = GetTickCount();
1419 if (!timer) timer = vtime;
1420 // 50ms no field --> card to idle state
1421 if (vtime - timer > 50) return 2;
1422 } else
1423 if (timer) timer = 0;
1424 analogCnt = 0;
1425 analogAVG = 0;
1426 }
1427 }
1428
1429 // receive and test the miller decoding
1430 if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
1431 b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
1432 if(MillerDecoding(b, 0)) {
1433 *len = Uart.len;
1434 return 0;
1435 }
1436 }
1437
1438 }
1439 }
1440
1441
1442 static int EmSendCmd14443aRaw(uint8_t *resp, uint16_t respLen, bool correctionNeeded)
1443 {
1444 uint8_t b;
1445 uint16_t i = 0;
1446 uint32_t ThisTransferTime;
1447
1448 // Modulate Manchester
1449 FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_TAGSIM_MOD);
1450
1451 // include correction bit if necessary
1452 if (Uart.parityBits & 0x01) {
1453 correctionNeeded = TRUE;
1454 }
1455 if(correctionNeeded) {
1456 // 1236, so correction bit needed
1457 i = 0;
1458 } else {
1459 i = 1;
1460 }
1461
1462 // clear receiving shift register and holding register
1463 while(!(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY));
1464 b = AT91C_BASE_SSC->SSC_RHR; (void) b;
1465 while(!(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY));
1466 b = AT91C_BASE_SSC->SSC_RHR; (void) b;
1467
1468 // wait for the FPGA to signal fdt_indicator == 1 (the FPGA is ready to queue new data in its delay line)
1469 for (uint16_t j = 0; j < 5; j++) { // allow timeout - better late than never
1470 while(!(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY));
1471 if (AT91C_BASE_SSC->SSC_RHR) break;
1472 }
1473
1474 while ((ThisTransferTime = GetCountSspClk()) & 0x00000007);
1475
1476 // Clear TXRDY:
1477 AT91C_BASE_SSC->SSC_THR = SEC_F;
1478
1479 // send cycle
1480 for(; i < respLen; ) {
1481 if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
1482 AT91C_BASE_SSC->SSC_THR = resp[i++];
1483 FpgaSendQueueDelay = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
1484 }
1485
1486 if(BUTTON_PRESS()) {
1487 break;
1488 }
1489 }
1490
1491 // Ensure that the FPGA Delay Queue is empty before we switch to TAGSIM_LISTEN again:
1492 uint8_t fpga_queued_bits = FpgaSendQueueDelay >> 3;
1493 for (i = 0; i <= fpga_queued_bits/8 + 1; ) {
1494 if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
1495 AT91C_BASE_SSC->SSC_THR = SEC_F;
1496 FpgaSendQueueDelay = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
1497 i++;
1498 }
1499 }
1500
1501 LastTimeProxToAirStart = ThisTransferTime + (correctionNeeded?8:0);
1502
1503 return 0;
1504 }
1505
1506 int EmSend4bitEx(uint8_t resp, bool correctionNeeded){
1507 Code4bitAnswerAsTag(resp);
1508 int res = EmSendCmd14443aRaw(ToSend, ToSendMax, correctionNeeded);
1509 // do the tracing for the previous reader request and this tag answer:
1510 uint8_t par[1];
1511 GetParity(&resp, 1, par);
1512 EmLogTrace(Uart.output,
1513 Uart.len,
1514 Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG,
1515 Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG,
1516 Uart.parity,
1517 &resp,
1518 1,
1519 LastTimeProxToAirStart*16 + DELAY_ARM2AIR_AS_TAG,
1520 (LastTimeProxToAirStart + LastProxToAirDuration)*16 + DELAY_ARM2AIR_AS_TAG,
1521 par);
1522 return res;
1523 }
1524
1525 int EmSend4bit(uint8_t resp){
1526 return EmSend4bitEx(resp, false);
1527 }
1528
1529 int EmSendCmdExPar(uint8_t *resp, uint16_t respLen, bool correctionNeeded, uint8_t *par){
1530 CodeIso14443aAsTagPar(resp, respLen, par);
1531 int res = EmSendCmd14443aRaw(ToSend, ToSendMax, correctionNeeded);
1532 // do the tracing for the previous reader request and this tag answer:
1533 EmLogTrace(Uart.output,
1534 Uart.len,
1535 Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG,
1536 Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG,
1537 Uart.parity,
1538 resp,
1539 respLen,
1540 LastTimeProxToAirStart*16 + DELAY_ARM2AIR_AS_TAG,
1541 (LastTimeProxToAirStart + LastProxToAirDuration)*16 + DELAY_ARM2AIR_AS_TAG,
1542 par);
1543 return res;
1544 }
1545
1546 int EmSendCmdEx(uint8_t *resp, uint16_t respLen, bool correctionNeeded){
1547 uint8_t par[MAX_PARITY_SIZE];
1548 GetParity(resp, respLen, par);
1549 return EmSendCmdExPar(resp, respLen, correctionNeeded, par);
1550 }
1551
1552 int EmSendCmd(uint8_t *resp, uint16_t respLen){
1553 uint8_t par[MAX_PARITY_SIZE];
1554 GetParity(resp, respLen, par);
1555 return EmSendCmdExPar(resp, respLen, false, par);
1556 }
1557
1558 int EmSendCmdPar(uint8_t *resp, uint16_t respLen, uint8_t *par){
1559 return EmSendCmdExPar(resp, respLen, false, par);
1560 }
1561
1562 bool EmLogTrace(uint8_t *reader_data, uint16_t reader_len, uint32_t reader_StartTime, uint32_t reader_EndTime, uint8_t *reader_Parity,
1563 uint8_t *tag_data, uint16_t tag_len, uint32_t tag_StartTime, uint32_t tag_EndTime, uint8_t *tag_Parity)
1564 {
1565 if (tracing) {
1566 // we cannot exactly measure the end and start of a received command from reader. However we know that the delay from
1567 // end of the received command to start of the tag's (simulated by us) answer is n*128+20 or n*128+84 resp.
1568 // with n >= 9. The start of the tags answer can be measured and therefore the end of the received command be calculated:
1569 uint16_t reader_modlen = reader_EndTime - reader_StartTime;
1570 uint16_t approx_fdt = tag_StartTime - reader_EndTime;
1571 uint16_t exact_fdt = (approx_fdt - 20 + 32)/64 * 64 + 20;
1572 reader_EndTime = tag_StartTime - exact_fdt;
1573 reader_StartTime = reader_EndTime - reader_modlen;
1574 if (!LogTrace(reader_data, reader_len, reader_StartTime, reader_EndTime, reader_Parity, TRUE)) {
1575 return FALSE;
1576 } else return(!LogTrace(tag_data, tag_len, tag_StartTime, tag_EndTime, tag_Parity, FALSE));
1577 } else {
1578 return TRUE;
1579 }
1580 }
1581
1582 //-----------------------------------------------------------------------------
1583 // Wait a certain time for tag response
1584 // If a response is captured return TRUE
1585 // If it takes too long return FALSE
1586 //-----------------------------------------------------------------------------
1587 static int GetIso14443aAnswerFromTag(uint8_t *receivedResponse, uint8_t *receivedResponsePar, uint16_t offset)
1588 {
1589 uint32_t c;
1590
1591 // Set FPGA mode to "reader listen mode", no modulation (listen
1592 // only, since we are receiving, not transmitting).
1593 // Signal field is on with the appropriate LED
1594 LED_D_ON();
1595 FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_READER_LISTEN);
1596
1597 // Now get the answer from the card
1598 DemodInit(receivedResponse, receivedResponsePar);
1599
1600 // clear RXRDY:
1601 uint8_t b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
1602
1603 c = 0;
1604 for(;;) {
1605 WDT_HIT();
1606
1607 if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
1608 b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
1609 if(ManchesterDecoding(b, offset, 0)) {
1610 NextTransferTime = MAX(NextTransferTime, Demod.endTime - (DELAY_AIR2ARM_AS_READER + DELAY_ARM2AIR_AS_READER)/16 + FRAME_DELAY_TIME_PICC_TO_PCD);
1611 return TRUE;
1612 } else if (c++ > iso14a_timeout && Demod.state == DEMOD_UNSYNCD) {
1613 return FALSE;
1614 }
1615 }
1616 }
1617 }
1618
1619
1620 void ReaderTransmitBitsPar(uint8_t* frame, uint16_t bits, uint8_t *par, uint32_t *timing)
1621 {
1622 CodeIso14443aBitsAsReaderPar(frame, bits, par);
1623
1624 // Send command to tag
1625 TransmitFor14443a(ToSend, ToSendMax, timing);
1626 if(trigger)
1627 LED_A_ON();
1628
1629 // Log reader command in trace buffer
1630 if (tracing) {
1631 LogTrace(frame, nbytes(bits), LastTimeProxToAirStart*16 + DELAY_ARM2AIR_AS_READER, (LastTimeProxToAirStart + LastProxToAirDuration)*16 + DELAY_ARM2AIR_AS_READER, par, TRUE);
1632 }
1633 }
1634
1635
1636 void ReaderTransmitPar(uint8_t* frame, uint16_t len, uint8_t *par, uint32_t *timing)
1637 {
1638 ReaderTransmitBitsPar(frame, len*8, par, timing);
1639 }
1640
1641
1642 void ReaderTransmitBits(uint8_t* frame, uint16_t len, uint32_t *timing)
1643 {
1644 // Generate parity and redirect
1645 uint8_t par[MAX_PARITY_SIZE];
1646 GetParity(frame, len/8, par);
1647 ReaderTransmitBitsPar(frame, len, par, timing);
1648 }
1649
1650
1651 void ReaderTransmit(uint8_t* frame, uint16_t len, uint32_t *timing)
1652 {
1653 // Generate parity and redirect
1654 uint8_t par[MAX_PARITY_SIZE];
1655 GetParity(frame, len, par);
1656 ReaderTransmitBitsPar(frame, len*8, par, timing);
1657 }
1658
1659 int ReaderReceiveOffset(uint8_t* receivedAnswer, uint16_t offset, uint8_t *parity)
1660 {
1661 if (!GetIso14443aAnswerFromTag(receivedAnswer, parity, offset)) return FALSE;
1662 if (tracing) {
1663 LogTrace(receivedAnswer, Demod.len, Demod.startTime*16 - DELAY_AIR2ARM_AS_READER, Demod.endTime*16 - DELAY_AIR2ARM_AS_READER, parity, FALSE);
1664 }
1665 return Demod.len;
1666 }
1667
1668 int ReaderReceive(uint8_t *receivedAnswer, uint8_t *parity)
1669 {
1670 if (!GetIso14443aAnswerFromTag(receivedAnswer, parity, 0)) return FALSE;
1671 if (tracing) {
1672 LogTrace(receivedAnswer, Demod.len, Demod.startTime*16 - DELAY_AIR2ARM_AS_READER, Demod.endTime*16 - DELAY_AIR2ARM_AS_READER, parity, FALSE);
1673 }
1674 return Demod.len;
1675 }
1676
1677 /* performs iso14443a anticollision procedure
1678 * fills the uid pointer unless NULL
1679 * fills resp_data unless NULL */
1680 int iso14443a_select_card(byte_t *uid_ptr, iso14a_card_select_t *p_hi14a_card, uint32_t *cuid_ptr) {
1681 uint8_t wupa[] = { 0x52 }; // 0x26 - REQA 0x52 - WAKE-UP
1682 uint8_t sel_all[] = { 0x93,0x20 };
1683 uint8_t sel_uid[] = { 0x93,0x70,0x00,0x00,0x00,0x00,0x00,0x00,0x00};
1684 uint8_t rats[] = { 0xE0,0x80,0x00,0x00 }; // FSD=256, FSDI=8, CID=0
1685 uint8_t resp[MAX_FRAME_SIZE]; // theoretically. A usual RATS will be much smaller
1686 uint8_t resp_par[MAX_PARITY_SIZE];
1687 byte_t uid_resp[4];
1688 size_t uid_resp_len;
1689
1690 uint8_t sak = 0x04; // cascade uid
1691 int cascade_level = 0;
1692 int len;
1693
1694 // Broadcast for a card, WUPA (0x52) will force response from all cards in the field
1695 ReaderTransmitBitsPar(wupa,7,0, NULL);
1696
1697 // Receive the ATQA
1698 if(!ReaderReceive(resp, resp_par)) return 0;
1699
1700 if(p_hi14a_card) {
1701 memcpy(p_hi14a_card->atqa, resp, 2);
1702 p_hi14a_card->uidlen = 0;
1703 memset(p_hi14a_card->uid,0,10);
1704 }
1705
1706 // clear uid
1707 if (uid_ptr) {
1708 memset(uid_ptr,0,10);
1709 }
1710
1711 // check for proprietary anticollision:
1712 if ((resp[0] & 0x1F) == 0) {
1713 return 3;
1714 }
1715
1716 // OK we will select at least at cascade 1, lets see if first byte of UID was 0x88 in
1717 // which case we need to make a cascade 2 request and select - this is a long UID
1718 // While the UID is not complete, the 3nd bit (from the right) is set in the SAK.
1719 for(; sak & 0x04; cascade_level++) {
1720 // SELECT_* (L1: 0x93, L2: 0x95, L3: 0x97)
1721 sel_uid[0] = sel_all[0] = 0x93 + cascade_level * 2;
1722
1723 // SELECT_ALL
1724 ReaderTransmit(sel_all, sizeof(sel_all), NULL);
1725 if (!ReaderReceive(resp, resp_par)) return 0;
1726
1727 if (Demod.collisionPos) { // we had a collision and need to construct the UID bit by bit
1728 memset(uid_resp, 0, 4);
1729 uint16_t uid_resp_bits = 0;
1730 uint16_t collision_answer_offset = 0;
1731 // anti-collision-loop:
1732 while (Demod.collisionPos) {
1733 Dbprintf("Multiple tags detected. Collision after Bit %d", Demod.collisionPos);
1734 for (uint16_t i = collision_answer_offset; i < Demod.collisionPos; i++, uid_resp_bits++) { // add valid UID bits before collision point
1735 uint16_t UIDbit = (resp[i/8] >> (i % 8)) & 0x01;
1736 uid_resp[uid_resp_bits / 8] |= UIDbit << (uid_resp_bits % 8);
1737 }
1738 uid_resp[uid_resp_bits/8] |= 1 << (uid_resp_bits % 8); // next time select the card(s) with a 1 in the collision position
1739 uid_resp_bits++;
1740 // construct anticollosion command:
1741 sel_uid[1] = ((2 + uid_resp_bits/8) << 4) | (uid_resp_bits & 0x07); // length of data in bytes and bits
1742 for (uint16_t i = 0; i <= uid_resp_bits/8; i++) {
1743 sel_uid[2+i] = uid_resp[i];
1744 }
1745 collision_answer_offset = uid_resp_bits%8;
1746 ReaderTransmitBits(sel_uid, 16 + uid_resp_bits, NULL);
1747 if (!ReaderReceiveOffset(resp, collision_answer_offset, resp_par)) return 0;
1748 }
1749 // finally, add the last bits and BCC of the UID
1750 for (uint16_t i = collision_answer_offset; i < (Demod.len-1)*8; i++, uid_resp_bits++) {
1751 uint16_t UIDbit = (resp[i/8] >> (i%8)) & 0x01;
1752 uid_resp[uid_resp_bits/8] |= UIDbit << (uid_resp_bits % 8);
1753 }
1754
1755 } else { // no collision, use the response to SELECT_ALL as current uid
1756 memcpy(uid_resp, resp, 4);
1757 }
1758 uid_resp_len = 4;
1759
1760 // calculate crypto UID. Always use last 4 Bytes.
1761 if(cuid_ptr) {
1762 *cuid_ptr = bytes_to_num(uid_resp, 4);
1763 }
1764
1765 // Construct SELECT UID command
1766 sel_uid[1] = 0x70; // transmitting a full UID (1 Byte cmd, 1 Byte NVB, 4 Byte UID, 1 Byte BCC, 2 Bytes CRC)
1767 memcpy(sel_uid+2, uid_resp, 4); // the UID
1768 sel_uid[6] = sel_uid[2] ^ sel_uid[3] ^ sel_uid[4] ^ sel_uid[5]; // calculate and add BCC
1769 AppendCrc14443a(sel_uid, 7); // calculate and add CRC
1770 ReaderTransmit(sel_uid, sizeof(sel_uid), NULL);
1771
1772 // Receive the SAK
1773 if (!ReaderReceive(resp, resp_par)) return 0;
1774 sak = resp[0];
1775
1776 // Test if more parts of the uid are coming
1777 if ((sak & 0x04) /* && uid_resp[0] == 0x88 */) {
1778 // Remove first byte, 0x88 is not an UID byte, it CT, see page 3 of:
1779 // http://www.nxp.com/documents/application_note/AN10927.pdf
1780 uid_resp[0] = uid_resp[1];
1781 uid_resp[1] = uid_resp[2];
1782 uid_resp[2] = uid_resp[3];
1783
1784 uid_resp_len = 3;
1785 }
1786
1787 if(uid_ptr) {
1788 memcpy(uid_ptr + (cascade_level*3), uid_resp, uid_resp_len);
1789 }
1790
1791 if(p_hi14a_card) {
1792 memcpy(p_hi14a_card->uid + (cascade_level*3), uid_resp, uid_resp_len);
1793 p_hi14a_card->uidlen += uid_resp_len;
1794 }
1795 }
1796
1797 if(p_hi14a_card) {
1798 p_hi14a_card->sak = sak;
1799 p_hi14a_card->ats_len = 0;
1800 }
1801
1802 // non iso14443a compliant tag
1803 if( (sak & 0x20) == 0) return 2;
1804
1805 // Request for answer to select
1806 AppendCrc14443a(rats, 2);
1807 ReaderTransmit(rats, sizeof(rats), NULL);
1808
1809 if (!(len = ReaderReceive(resp, resp_par))) return 0;
1810
1811
1812 if(p_hi14a_card) {
1813 memcpy(p_hi14a_card->ats, resp, sizeof(p_hi14a_card->ats));
1814 p_hi14a_card->ats_len = len;
1815 }
1816
1817 // reset the PCB block number
1818 iso14_pcb_blocknum = 0;
1819
1820 // set default timeout based on ATS
1821 iso14a_set_ATS_timeout(resp);
1822
1823 return 1;
1824 }
1825
1826 void iso14443a_setup(uint8_t fpga_minor_mode) {
1827 FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
1828 // Set up the synchronous serial port
1829 FpgaSetupSsc();
1830 // connect Demodulated Signal to ADC:
1831 SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
1832
1833 // Signal field is on with the appropriate LED
1834 if (fpga_minor_mode == FPGA_HF_ISO14443A_READER_MOD
1835 || fpga_minor_mode == FPGA_HF_ISO14443A_READER_LISTEN) {
1836 LED_D_ON();
1837 } else {
1838 LED_D_OFF();
1839 }
1840 FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | fpga_minor_mode);
1841
1842 // Start the timer
1843 StartCountSspClk();
1844
1845 DemodReset();
1846 UartReset();
1847 NextTransferTime = 2*DELAY_ARM2AIR_AS_READER;
1848 iso14a_set_timeout(1050); // 10ms default
1849 }
1850
1851 int iso14_apdu(uint8_t *cmd, uint16_t cmd_len, void *data) {
1852 uint8_t parity[MAX_PARITY_SIZE];
1853 uint8_t real_cmd[cmd_len+4];
1854 real_cmd[0] = 0x0a; //I-Block
1855 // put block number into the PCB
1856 real_cmd[0] |= iso14_pcb_blocknum;
1857 real_cmd[1] = 0x00; //CID: 0 //FIXME: allow multiple selected cards
1858 memcpy(real_cmd+2, cmd, cmd_len);
1859 AppendCrc14443a(real_cmd,cmd_len+2);
1860
1861 ReaderTransmit(real_cmd, cmd_len+4, NULL);
1862 size_t len = ReaderReceive(data, parity);
1863 uint8_t *data_bytes = (uint8_t *) data;
1864 if (!len)
1865 return 0; //DATA LINK ERROR
1866 // if we received an I- or R(ACK)-Block with a block number equal to the
1867 // current block number, toggle the current block number
1868 else if (len >= 4 // PCB+CID+CRC = 4 bytes
1869 && ((data_bytes[0] & 0xC0) == 0 // I-Block
1870 || (data_bytes[0] & 0xD0) == 0x80) // R-Block with ACK bit set to 0
1871 && (data_bytes[0] & 0x01) == iso14_pcb_blocknum) // equal block numbers
1872 {
1873 iso14_pcb_blocknum ^= 1;
1874 }
1875
1876 return len;
1877 }
1878
1879 //-----------------------------------------------------------------------------
1880 // Read an ISO 14443a tag. Send out commands and store answers.
1881 //
1882 //-----------------------------------------------------------------------------
1883 void ReaderIso14443a(UsbCommand *c)
1884 {
1885 iso14a_command_t param = c->arg[0];
1886 uint8_t *cmd = c->d.asBytes;
1887 size_t len = c->arg[1] & 0xffff;
1888 size_t lenbits = c->arg[1] >> 16;
1889 uint32_t timeout = c->arg[2];
1890 uint32_t arg0 = 0;
1891 byte_t buf[USB_CMD_DATA_SIZE];
1892 uint8_t par[MAX_PARITY_SIZE];
1893
1894 if(param & ISO14A_CONNECT) {
1895 clear_trace();
1896 }
1897
1898 set_tracing(TRUE);
1899
1900 if(param & ISO14A_REQUEST_TRIGGER) {
1901 iso14a_set_trigger(TRUE);
1902 }
1903
1904 if(param & ISO14A_CONNECT) {
1905 iso14443a_setup(FPGA_HF_ISO14443A_READER_LISTEN);
1906 if(!(param & ISO14A_NO_SELECT)) {
1907 iso14a_card_select_t *card = (iso14a_card_select_t*)buf;
1908 arg0 = iso14443a_select_card(NULL,card,NULL);
1909 cmd_send(CMD_ACK,arg0,card->uidlen,0,buf,sizeof(iso14a_card_select_t));
1910 }
1911 }
1912
1913 if(param & ISO14A_SET_TIMEOUT) {
1914 iso14a_set_timeout(timeout);
1915 }
1916
1917 if(param & ISO14A_APDU) {
1918 arg0 = iso14_apdu(cmd, len, buf);
1919 cmd_send(CMD_ACK,arg0,0,0,buf,sizeof(buf));
1920 }
1921
1922 if(param & ISO14A_RAW) {
1923 if(param & ISO14A_APPEND_CRC) {
1924 if(param & ISO14A_TOPAZMODE) {
1925 AppendCrc14443b(cmd,len);
1926 } else {
1927 AppendCrc14443a(cmd,len);
1928 }
1929 len += 2;
1930 if (lenbits) lenbits += 16;
1931 }
1932 if(lenbits>0) { // want to send a specific number of bits (e.g. short commands)
1933 if(param & ISO14A_TOPAZMODE) {
1934 int bits_to_send = lenbits;
1935 uint16_t i = 0;
1936 ReaderTransmitBitsPar(&cmd[i++], MIN(bits_to_send, 7), NULL, NULL); // first byte is always short (7bits) and no parity
1937 bits_to_send -= 7;
1938 while (bits_to_send > 0) {
1939 ReaderTransmitBitsPar(&cmd[i++], MIN(bits_to_send, 8), NULL, NULL); // following bytes are 8 bit and no parity
1940 bits_to_send -= 8;
1941 }
1942 } else {
1943 GetParity(cmd, lenbits/8, par);
1944 ReaderTransmitBitsPar(cmd, lenbits, par, NULL); // bytes are 8 bit with odd parity
1945 }
1946 } else { // want to send complete bytes only
1947 if(param & ISO14A_TOPAZMODE) {
1948 uint16_t i = 0;
1949 ReaderTransmitBitsPar(&cmd[i++], 7, NULL, NULL); // first byte: 7 bits, no paritiy
1950 while (i < len) {
1951 ReaderTransmitBitsPar(&cmd[i++], 8, NULL, NULL); // following bytes: 8 bits, no paritiy
1952 }
1953 } else {
1954 ReaderTransmit(cmd,len, NULL); // 8 bits, odd parity
1955 }
1956 }
1957 arg0 = ReaderReceive(buf, par);
1958 cmd_send(CMD_ACK,arg0,0,0,buf,sizeof(buf));
1959 }
1960
1961 if(param & ISO14A_REQUEST_TRIGGER) {
1962 iso14a_set_trigger(FALSE);
1963 }
1964
1965 if(param & ISO14A_NO_DISCONNECT) {
1966 return;
1967 }
1968
1969 FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
1970 LEDsoff();
1971 }
1972
1973
1974 // Determine the distance between two nonces.
1975 // Assume that the difference is small, but we don't know which is first.
1976 // Therefore try in alternating directions.
1977 int32_t dist_nt(uint32_t nt1, uint32_t nt2) {
1978
1979 uint16_t i;
1980 uint32_t nttmp1, nttmp2;
1981
1982 if (nt1 == nt2) return 0;
1983
1984 nttmp1 = nt1;
1985 nttmp2 = nt2;
1986
1987 for (i = 1; i < 32768; i++) {
1988 nttmp1 = prng_successor(nttmp1, 1);
1989 if (nttmp1 == nt2) return i;
1990 nttmp2 = prng_successor(nttmp2, 1);
1991 if (nttmp2 == nt1) return -i;
1992 }
1993
1994 return(-99999); // either nt1 or nt2 are invalid nonces
1995 }
1996
1997
1998 //-----------------------------------------------------------------------------
1999 // Recover several bits of the cypher stream. This implements (first stages of)
2000 // the algorithm described in "The Dark Side of Security by Obscurity and
2001 // Cloning MiFare Classic Rail and Building Passes, Anywhere, Anytime"
2002 // (article by Nicolas T. Courtois, 2009)
2003 //-----------------------------------------------------------------------------
2004 void ReaderMifare(bool first_try)
2005 {
2006 // Mifare AUTH
2007 uint8_t mf_auth[] = { 0x60,0x00,0xf5,0x7b };
2008 uint8_t mf_nr_ar[] = { 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00 };
2009 static uint8_t mf_nr_ar3;
2010
2011 uint8_t receivedAnswer[MAX_MIFARE_FRAME_SIZE];
2012 uint8_t receivedAnswerPar[MAX_MIFARE_PARITY_SIZE];
2013
2014 if (first_try) {
2015 iso14443a_setup(FPGA_HF_ISO14443A_READER_MOD);
2016 }
2017
2018 // free eventually allocated BigBuf memory. We want all for tracing.
2019 BigBuf_free();
2020
2021 clear_trace();
2022 set_tracing(TRUE);
2023
2024 byte_t nt_diff = 0;
2025 uint8_t par[1] = {0}; // maximum 8 Bytes to be sent here, 1 byte parity is therefore enough
2026 static byte_t par_low = 0;
2027 bool led_on = TRUE;
2028 uint8_t uid[10] ={0};
2029 uint32_t cuid;
2030
2031 uint32_t nt = 0;
2032 uint32_t previous_nt = 0;
2033 static uint32_t nt_attacked = 0;
2034 byte_t par_list[8] = {0x00};
2035 byte_t ks_list[8] = {0x00};
2036
2037 #define PRNG_SEQUENCE_LENGTH (1 << 16);
2038 static uint32_t sync_time;
2039 static int32_t sync_cycles;
2040 int catch_up_cycles = 0;
2041 int last_catch_up = 0;
2042 uint16_t elapsed_prng_sequences;
2043 uint16_t consecutive_resyncs = 0;
2044 int isOK = 0;
2045
2046 if (first_try) {
2047 mf_nr_ar3 = 0;
2048 sync_time = GetCountSspClk() & 0xfffffff8;
2049 sync_cycles = PRNG_SEQUENCE_LENGTH; // theory: Mifare Classic's random generator repeats every 2^16 cycles (and so do the tag nonces).
2050 nt_attacked = 0;
2051 par[0] = 0;
2052 }
2053 else {
2054 // we were unsuccessful on a previous call. Try another READER nonce (first 3 parity bits remain the same)
2055 mf_nr_ar3++;
2056 mf_nr_ar[3] = mf_nr_ar3;
2057 par[0] = par_low;
2058 }
2059
2060 LED_A_ON();
2061 LED_B_OFF();
2062 LED_C_OFF();
2063
2064
2065 #define MAX_UNEXPECTED_RANDOM 4 // maximum number of unexpected (i.e. real) random numbers when trying to sync. Then give up.
2066 #define MAX_SYNC_TRIES 32
2067 #define NUM_DEBUG_INFOS 8 // per strategy
2068 #define MAX_STRATEGY 3
2069 uint16_t unexpected_random = 0;
2070 uint16_t sync_tries = 0;
2071 int16_t debug_info_nr = -1;
2072 uint16_t strategy = 0;
2073 int32_t debug_info[MAX_STRATEGY][NUM_DEBUG_INFOS];
2074 uint32_t select_time;
2075 uint32_t halt_time;
2076
2077 for(uint16_t i = 0; TRUE; i++) {
2078
2079 LED_C_ON();
2080 WDT_HIT();
2081
2082 // Test if the action was cancelled
2083 if(BUTTON_PRESS()) {
2084 isOK = -1;
2085 break;
2086 }
2087
2088 if (strategy == 2) {
2089 // test with additional hlt command
2090 halt_time = 0;
2091 int len = mifare_sendcmd_short(NULL, false, 0x50, 0x00, receivedAnswer, receivedAnswerPar, &halt_time);
2092 if (len && MF_DBGLEVEL >= 3) {
2093 Dbprintf("Unexpected response of %d bytes to hlt command (additional debugging).", len);
2094 }
2095 }
2096
2097 if (strategy == 3) {
2098 // test with FPGA power off/on
2099 FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
2100 SpinDelay(200);
2101 iso14443a_setup(FPGA_HF_ISO14443A_READER_MOD);
2102 SpinDelay(100);
2103 }
2104
2105 if(!iso14443a_select_card(uid, NULL, &cuid)) {
2106 if (MF_DBGLEVEL >= 1) Dbprintf("Mifare: Can't select card");
2107 continue;
2108 }
2109 select_time = GetCountSspClk();
2110
2111 elapsed_prng_sequences = 1;
2112 if (debug_info_nr == -1) {
2113 sync_time = (sync_time & 0xfffffff8) + sync_cycles + catch_up_cycles;
2114 catch_up_cycles = 0;
2115
2116 // if we missed the sync time already, advance to the next nonce repeat
2117 while(GetCountSspClk() > sync_time) {
2118 elapsed_prng_sequences++;
2119 sync_time = (sync_time & 0xfffffff8) + sync_cycles;
2120 }
2121
2122 // Transmit MIFARE_CLASSIC_AUTH at synctime. Should result in returning the same tag nonce (== nt_attacked)
2123 ReaderTransmit(mf_auth, sizeof(mf_auth), &sync_time);
2124 } else {
2125 // collect some information on tag nonces for debugging:
2126 #define DEBUG_FIXED_SYNC_CYCLES PRNG_SEQUENCE_LENGTH
2127 if (strategy == 0) {
2128 // nonce distances at fixed time after card select:
2129 sync_time = select_time + DEBUG_FIXED_SYNC_CYCLES;
2130 } else if (strategy == 1) {
2131 // nonce distances at fixed time between authentications:
2132 sync_time = sync_time + DEBUG_FIXED_SYNC_CYCLES;
2133 } else if (strategy == 2) {
2134 // nonce distances at fixed time after halt:
2135 sync_time = halt_time + DEBUG_FIXED_SYNC_CYCLES;
2136 } else {
2137 // nonce_distances at fixed time after power on
2138 sync_time = DEBUG_FIXED_SYNC_CYCLES;
2139 }
2140 ReaderTransmit(mf_auth, sizeof(mf_auth), &sync_time);
2141 }
2142
2143 // Receive the (4 Byte) "random" nonce
2144 if (!ReaderReceive(receivedAnswer, receivedAnswerPar)) {
2145 if (MF_DBGLEVEL >= 1) Dbprintf("Mifare: Couldn't receive tag nonce");
2146 continue;
2147 }
2148
2149 previous_nt = nt;
2150 nt = bytes_to_num(receivedAnswer, 4);
2151
2152 // Transmit reader nonce with fake par
2153 ReaderTransmitPar(mf_nr_ar, sizeof(mf_nr_ar), par, NULL);
2154
2155 if (first_try && previous_nt && !nt_attacked) { // we didn't calibrate our clock yet
2156 int nt_distance = dist_nt(previous_nt, nt);
2157 if (nt_distance == 0) {
2158 nt_attacked = nt;
2159 } else {
2160 if (nt_distance == -99999) { // invalid nonce received
2161 unexpected_random++;
2162 if (unexpected_random > MAX_UNEXPECTED_RANDOM) {
2163 isOK = -3; // Card has an unpredictable PRNG. Give up
2164 break;
2165 } else {
2166 continue; // continue trying...
2167 }
2168 }
2169 if (++sync_tries > MAX_SYNC_TRIES) {
2170 if (strategy > MAX_STRATEGY || MF_DBGLEVEL < 3) {
2171 isOK = -4; // Card's PRNG runs at an unexpected frequency or resets unexpectedly
2172 break;
2173 } else { // continue for a while, just to collect some debug info
2174 debug_info[strategy][debug_info_nr] = nt_distance;
2175 debug_info_nr++;
2176 if (debug_info_nr == NUM_DEBUG_INFOS) {
2177 strategy++;
2178 debug_info_nr = 0;
2179 }
2180 continue;
2181 }
2182 }
2183 sync_cycles = (sync_cycles - nt_distance/elapsed_prng_sequences);
2184 if (sync_cycles <= 0) {
2185 sync_cycles += PRNG_SEQUENCE_LENGTH;
2186 }
2187 if (MF_DBGLEVEL >= 3) {
2188 Dbprintf("calibrating in cycle %d. nt_distance=%d, elapsed_prng_sequences=%d, new sync_cycles: %d\n", i, nt_distance, elapsed_prng_sequences, sync_cycles);
2189 }
2190 continue;
2191 }
2192 }
2193
2194 if ((nt != nt_attacked) && nt_attacked) { // we somehow lost sync. Try to catch up again...
2195 catch_up_cycles = -dist_nt(nt_attacked, nt);
2196 if (catch_up_cycles == 99999) { // invalid nonce received. Don't resync on that one.
2197 catch_up_cycles = 0;
2198 continue;
2199 }
2200 catch_up_cycles /= elapsed_prng_sequences;
2201 if (catch_up_cycles == last_catch_up) {
2202 consecutive_resyncs++;
2203 }
2204 else {
2205 last_catch_up = catch_up_cycles;
2206 consecutive_resyncs = 0;
2207 }
2208 if (consecutive_resyncs < 3) {
2209 if (MF_DBGLEVEL >= 3) Dbprintf("Lost sync in cycle %d. nt_distance=%d. Consecutive Resyncs = %d. Trying one time catch up...\n", i, -catch_up_cycles, consecutive_resyncs);
2210 }
2211 else {
2212 sync_cycles = sync_cycles + catch_up_cycles;
2213 if (MF_DBGLEVEL >= 3) Dbprintf("Lost sync in cycle %d for the fourth time consecutively (nt_distance = %d). Adjusting sync_cycles to %d.\n", i, -catch_up_cycles, sync_cycles);
2214 last_catch_up = 0;
2215 catch_up_cycles = 0;
2216 consecutive_resyncs = 0;
2217 }
2218 continue;
2219 }
2220
2221 consecutive_resyncs = 0;
2222
2223 // Receive answer. This will be a 4 Bit NACK when the 8 parity bits are OK after decoding
2224 if (ReaderReceive(receivedAnswer, receivedAnswerPar)) {
2225 catch_up_cycles = 8; // the PRNG is delayed by 8 cycles due to the NAC (4Bits = 0x05 encrypted) transfer
2226
2227 if (nt_diff == 0) {
2228 par_low = par[0] & 0xE0; // there is no need to check all parities for other nt_diff. Parity Bits for mf_nr_ar[0..2] won't change
2229 }
2230
2231 led_on = !led_on;
2232 if(led_on) LED_B_ON(); else LED_B_OFF();
2233
2234 par_list[nt_diff] = SwapBits(par[0], 8);
2235 ks_list[nt_diff] = receivedAnswer[0] ^ 0x05;
2236
2237 // Test if the information is complete
2238 if (nt_diff == 0x07) {
2239 isOK = 1;
2240 break;
2241 }
2242
2243 nt_diff = (nt_diff + 1) & 0x07;
2244 mf_nr_ar[3] = (mf_nr_ar[3] & 0x1F) | (nt_diff << 5);
2245 par[0] = par_low;
2246 } else {
2247 if (nt_diff == 0 && first_try)
2248 {
2249 par[0]++;
2250 if (par[0] == 0x00) { // tried all 256 possible parities without success. Card doesn't send NACK.
2251 isOK = -2;
2252 break;
2253 }
2254 } else {
2255 par[0] = ((par[0] & 0x1F) + 1) | par_low;
2256 }
2257 }
2258 }
2259
2260
2261 mf_nr_ar[3] &= 0x1F;
2262
2263 if (isOK == -4) {
2264 if (MF_DBGLEVEL >= 3) {
2265 for (uint16_t i = 0; i <= MAX_STRATEGY; i++) {
2266 for(uint16_t j = 0; j < NUM_DEBUG_INFOS; j++) {
2267 Dbprintf("collected debug info[%d][%d] = %d", i, j, debug_info[i][j]);
2268 }
2269 }
2270 }
2271 }
2272
2273 byte_t buf[28];
2274 memcpy(buf + 0, uid, 4);
2275 num_to_bytes(nt, 4, buf + 4);
2276 memcpy(buf + 8, par_list, 8);
2277 memcpy(buf + 16, ks_list, 8);
2278 memcpy(buf + 24, mf_nr_ar, 4);
2279
2280 cmd_send(CMD_ACK, isOK, 0, 0, buf, 28);
2281
2282 // Thats it...
2283 FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
2284 LEDsoff();
2285
2286 set_tracing(FALSE);
2287 }
2288
2289 typedef struct {
2290 uint32_t cuid;
2291 uint8_t sector;
2292 uint8_t keytype;
2293 uint32_t nonce;
2294 uint32_t ar;
2295 uint32_t nr;
2296 uint32_t nonce2;
2297 uint32_t ar2;
2298 uint32_t nr2;
2299 } nonces_t;
2300
2301 /**
2302 *MIFARE 1K simulate.
2303 *
2304 *@param flags :
2305 * FLAG_INTERACTIVE - In interactive mode, we are expected to finish the operation with an ACK
2306 * FLAG_4B_UID_IN_DATA - means that there is a 4-byte UID in the data-section, we're expected to use that
2307 * FLAG_7B_UID_IN_DATA - means that there is a 7-byte UID in the data-section, we're expected to use that
2308 * FLAG_10B_UID_IN_DATA - use 10-byte UID in the data-section not finished
2309 * FLAG_NR_AR_ATTACK - means we should collect NR_AR responses for bruteforcing later
2310 * FLAG_RANDOM_NONCE - means we should generate some pseudo-random nonce data (only allows moebius attack)
2311 *@param exitAfterNReads, exit simulation after n blocks have been read, 0 is infinite ...
2312 * (unless reader attack mode enabled then it runs util it gets enough nonces to recover all keys attmpted)
2313 */
2314 void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *datain)
2315 {
2316 int cardSTATE = MFEMUL_NOFIELD;
2317 int _UID_LEN = 0; // 4, 7, 10
2318 int vHf = 0; // in mV
2319 int res;
2320 uint32_t selTimer = 0;
2321 uint32_t authTimer = 0;
2322 uint16_t len = 0;
2323 uint8_t cardWRBL = 0;
2324 uint8_t cardAUTHSC = 0;
2325 uint8_t cardAUTHKEY = 0xff; // no authentication
2326 uint32_t cardRr = 0;
2327 uint32_t cuid = 0;
2328 //uint32_t rn_enc = 0;
2329 uint32_t ans = 0;
2330 uint32_t cardINTREG = 0;
2331 uint8_t cardINTBLOCK = 0;
2332 struct Crypto1State mpcs = {0, 0};
2333 struct Crypto1State *pcs;
2334 pcs = &mpcs;
2335 uint32_t numReads = 0;//Counts numer of times reader read a block
2336 uint8_t receivedCmd[MAX_MIFARE_FRAME_SIZE];
2337 uint8_t receivedCmd_par[MAX_MIFARE_PARITY_SIZE];
2338 uint8_t response[MAX_MIFARE_FRAME_SIZE];
2339 uint8_t response_par[MAX_MIFARE_PARITY_SIZE];
2340
2341 uint8_t rATQA[] = {0x04, 0x00}; // Mifare classic 1k 4BUID
2342 uint8_t rUIDBCC1[] = {0xde, 0xad, 0xbe, 0xaf, 0x62};
2343 uint8_t rUIDBCC2[] = {0xde, 0xad, 0xbe, 0xaf, 0x62}; // !!!
2344 uint8_t rUIDBCC3[] = {0xde, 0xad, 0xbe, 0xaf, 0x62};
2345
2346 uint8_t rSAKfinal[]= {0x08, 0xb6, 0xdd}; // mifare 1k indicated
2347 uint8_t rSAK1[] = {0x04, 0xda, 0x17}; // indicate UID not finished
2348
2349 uint8_t rAUTH_NT[] = {0x01, 0x02, 0x03, 0x04};
2350 uint8_t rAUTH_AT[] = {0x00, 0x00, 0x00, 0x00};
2351
2352 //Here, we collect UID,sector,keytype,NT,AR,NR,NT2,AR2,NR2
2353 // This will be used in the reader-only attack.
2354
2355 //allow collecting up to 8 sets of nonces to allow recovery of up to 8 keys
2356 #define ATTACK_KEY_COUNT 8 // keep same as define in cmdhfmf.c -> readerAttack()
2357 nonces_t ar_nr_resp[ATTACK_KEY_COUNT*2]; //*2 for 2 separate attack types (nml, moebius)
2358 memset(ar_nr_resp, 0x00, sizeof(ar_nr_resp));
2359
2360 uint8_t ar_nr_collected[ATTACK_KEY_COUNT*2]; //*2 for 2nd attack type (moebius)
2361 memset(ar_nr_collected, 0x00, sizeof(ar_nr_collected));
2362 uint8_t nonce1_count = 0;
2363 uint8_t nonce2_count = 0;
2364 uint8_t moebius_n_count = 0;
2365 bool gettingMoebius = false;
2366 uint8_t mM = 0; //moebius_modifier for collection storage
2367
2368 // Authenticate response - nonce
2369 uint32_t nonce;
2370 if (flags & FLAG_RANDOM_NONCE) {
2371 nonce = prand();
2372 } else {
2373 nonce = bytes_to_num(rAUTH_NT, 4);
2374 }
2375
2376 //-- Determine the UID
2377 // Can be set from emulator memory, incoming data
2378 // and can be 7 or 4 bytes long
2379 if (flags & FLAG_4B_UID_IN_DATA)
2380 {
2381 // 4B uid comes from data-portion of packet
2382 memcpy(rUIDBCC1,datain,4);
2383 rUIDBCC1[4] = rUIDBCC1[0] ^ rUIDBCC1[1] ^ rUIDBCC1[2] ^ rUIDBCC1[3];
2384 _UID_LEN = 4;
2385 } else if (flags & FLAG_7B_UID_IN_DATA) {
2386 // 7B uid comes from data-portion of packet
2387 memcpy(&rUIDBCC1[1],datain,3);
2388 memcpy(rUIDBCC2, datain+3, 4);
2389 _UID_LEN = 7;
2390 } else if (flags & FLAG_10B_UID_IN_DATA) {
2391 memcpy(&rUIDBCC1[1], datain, 3);
2392 memcpy(&rUIDBCC2[1], datain+3, 3);
2393 memcpy( rUIDBCC3, datain+6, 4);
2394 _UID_LEN = 10;
2395 } else {
2396 // get UID from emul memory - guess at length
2397 emlGetMemBt(receivedCmd, 7, 1);
2398 if (receivedCmd[0] == 0x00) { // ---------- 4BUID
2399 emlGetMemBt(rUIDBCC1, 0, 4);
2400 _UID_LEN = 4;
2401 } else { // ---------- 7BUID
2402 emlGetMemBt(&rUIDBCC1[1], 0, 3);
2403 emlGetMemBt(rUIDBCC2, 3, 4);
2404 _UID_LEN = 7;
2405 }
2406 }
2407
2408 switch (_UID_LEN) {
2409 case 4:
2410 // save CUID
2411 cuid = bytes_to_num(rUIDBCC1, 4);
2412 // BCC
2413 rUIDBCC1[4] = rUIDBCC1[0] ^ rUIDBCC1[1] ^ rUIDBCC1[2] ^ rUIDBCC1[3];
2414 if (MF_DBGLEVEL >= 2) {
2415 Dbprintf("4B UID: %02x%02x%02x%02x",
2416 rUIDBCC1[0],
2417 rUIDBCC1[1],
2418 rUIDBCC1[2],
2419 rUIDBCC1[3]
2420 );
2421 }
2422 break;
2423 case 7:
2424 rATQA[0] |= 0x40;
2425 // save CUID
2426 cuid = bytes_to_num(rUIDBCC2, 4);
2427 // CascadeTag, CT
2428 rUIDBCC1[0] = 0x88;
2429 // BCC
2430 rUIDBCC1[4] = rUIDBCC1[0] ^ rUIDBCC1[1] ^ rUIDBCC1[2] ^ rUIDBCC1[3];
2431 rUIDBCC2[4] = rUIDBCC2[0] ^ rUIDBCC2[1] ^ rUIDBCC2[2] ^ rUIDBCC2[3];
2432 if (MF_DBGLEVEL >= 2) {
2433 Dbprintf("7B UID: %02x %02x %02x %02x %02x %02x %02x",
2434 rUIDBCC1[1],
2435 rUIDBCC1[2],
2436 rUIDBCC1[3],
2437 rUIDBCC2[0],
2438 rUIDBCC2[1],
2439 rUIDBCC2[2],
2440 rUIDBCC2[3]
2441 );
2442 }
2443 break;
2444 case 10:
2445 rATQA[0] |= 0x80;
2446 //sak_10[0] &= 0xFB;
2447 // save CUID
2448 cuid = bytes_to_num(rUIDBCC3, 4);
2449 // CascadeTag, CT
2450 rUIDBCC1[0] = 0x88;
2451 rUIDBCC2[0] = 0x88;
2452 // BCC
2453 rUIDBCC1[4] = rUIDBCC1[0] ^ rUIDBCC1[1] ^ rUIDBCC1[2] ^ rUIDBCC1[3];
2454 rUIDBCC2[4] = rUIDBCC2[0] ^ rUIDBCC2[1] ^ rUIDBCC2[2] ^ rUIDBCC2[3];
2455 rUIDBCC3[4] = rUIDBCC3[0] ^ rUIDBCC3[1] ^ rUIDBCC3[2] ^ rUIDBCC3[3];
2456
2457 if (MF_DBGLEVEL >= 2) {
2458 Dbprintf("10B UID: %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x",
2459 rUIDBCC1[1],
2460 rUIDBCC1[2],
2461 rUIDBCC1[3],
2462 rUIDBCC2[1],
2463 rUIDBCC2[2],
2464 rUIDBCC2[3],
2465 rUIDBCC3[0],
2466 rUIDBCC3[1],
2467 rUIDBCC3[2],
2468 rUIDBCC3[3]
2469 );
2470 }
2471 break;
2472 default:
2473 break;
2474 }
2475
2476 // We need to listen to the high-frequency, peak-detected path.
2477 iso14443a_setup(FPGA_HF_ISO14443A_TAGSIM_LISTEN);
2478
2479 // free eventually allocated BigBuf memory but keep Emulator Memory
2480 BigBuf_free_keep_EM();
2481
2482 // clear trace
2483 clear_trace();
2484 set_tracing(TRUE);
2485
2486 bool finished = FALSE;
2487 bool button_pushed = BUTTON_PRESS();
2488 while (!button_pushed && !finished && !usb_poll_validate_length()) {
2489 WDT_HIT();
2490
2491 // find reader field
2492 if (cardSTATE == MFEMUL_NOFIELD) {
2493 vHf = (MAX_ADC_HF_VOLTAGE * AvgAdc(ADC_CHAN_HF)) >> 10;
2494 if (vHf > MF_MINFIELDV) {
2495 cardSTATE_TO_IDLE();
2496 LED_A_ON();
2497 }
2498 }
2499 if (cardSTATE == MFEMUL_NOFIELD) continue;
2500
2501 //Now, get data
2502 res = EmGetCmd(receivedCmd, &len, receivedCmd_par);
2503 if (res == 2) { //Field is off!
2504 cardSTATE = MFEMUL_NOFIELD;
2505 LEDsoff();
2506 continue;
2507 } else if (res == 1) {
2508 break; //return value 1 means button press
2509 }
2510
2511 // REQ or WUP request in ANY state and WUP in HALTED state
2512 if (len == 1 && ((receivedCmd[0] == ISO14443A_CMD_REQA && cardSTATE != MFEMUL_HALTED) || receivedCmd[0] == ISO14443A_CMD_WUPA)) {
2513 selTimer = GetTickCount();
2514 EmSendCmdEx(rATQA, sizeof(rATQA), (receivedCmd[0] == ISO14443A_CMD_WUPA));
2515 cardSTATE = MFEMUL_SELECT1;
2516
2517 // init crypto block
2518 LED_B_OFF();
2519 LED_C_OFF();
2520 crypto1_destroy(pcs);
2521 cardAUTHKEY = 0xff;
2522 if (flags & FLAG_RANDOM_NONCE) {
2523 nonce = prand();
2524 }
2525 continue;
2526 }
2527
2528 switch (cardSTATE) {
2529 case MFEMUL_NOFIELD:
2530 case MFEMUL_HALTED:
2531 case MFEMUL_IDLE:{
2532 LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parity, TRUE);
2533 break;
2534 }
2535 case MFEMUL_SELECT1:{
2536 // select all - 0x93 0x20
2537 if (len == 2 && (receivedCmd[0] == ISO14443A_CMD_ANTICOLL_OR_SELECT && receivedCmd[1] == 0x20)) {
2538 if (MF_DBGLEVEL >= 4) Dbprintf("SELECT ALL received");
2539 EmSendCmd(rUIDBCC1, sizeof(rUIDBCC1));
2540 break;
2541 }
2542
2543 // select card - 0x93 0x70 ...
2544 if (len == 9 &&
2545 (receivedCmd[0] == ISO14443A_CMD_ANTICOLL_OR_SELECT && receivedCmd[1] == 0x70 && memcmp(&receivedCmd[2], rUIDBCC1, 4) == 0)) {
2546 if (MF_DBGLEVEL >= 4)
2547 Dbprintf("SELECT %02x%02x%02x%02x received",receivedCmd[2],receivedCmd[3],receivedCmd[4],receivedCmd[5]);
2548
2549 switch(_UID_LEN) {
2550 case 4:
2551 cardSTATE = MFEMUL_WORK;
2552 LED_B_ON();
2553 if (MF_DBGLEVEL >= 4) Dbprintf("--> WORK. anticol1 time: %d", GetTickCount() - selTimer);
2554 EmSendCmd(rSAKfinal, sizeof(rSAKfinal));
2555 break;
2556 case 7:
2557 cardSTATE = MFEMUL_SELECT2;
2558 EmSendCmd(rSAK1, sizeof(rSAK1));
2559 break;
2560 case 10:
2561 cardSTATE = MFEMUL_SELECT2;
2562 EmSendCmd(rSAK1, sizeof(rSAK1));
2563 break;
2564 default:break;
2565 }
2566 } else {
2567 cardSTATE_TO_IDLE();
2568 }
2569 break;
2570 }
2571 case MFEMUL_SELECT3:{
2572 if (!len) {
2573 LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parity, TRUE);
2574 break;
2575 }
2576 // select all cl3 - 0x97 0x20
2577 if (len == 2 && (receivedCmd[0] == ISO14443A_CMD_ANTICOLL_OR_SELECT_3 && receivedCmd[1] == 0x20)) {
2578 EmSendCmd(rUIDBCC3, sizeof(rUIDBCC3));
2579 break;
2580 }
2581 // select card cl3 - 0x97 0x70
2582 if (len == 9 &&
2583 (receivedCmd[0] == ISO14443A_CMD_ANTICOLL_OR_SELECT_3 &&
2584 receivedCmd[1] == 0x70 &&
2585 memcmp(&receivedCmd[2], rUIDBCC3, 4) == 0) ) {
2586
2587 EmSendCmd(rSAKfinal, sizeof(rSAKfinal));
2588 cardSTATE = MFEMUL_WORK;
2589 LED_B_ON();
2590 if (MF_DBGLEVEL >= 4) Dbprintf("--> WORK. anticol3 time: %d", GetTickCount() - selTimer);
2591 break;
2592 }
2593 cardSTATE_TO_IDLE();
2594 break;
2595 }
2596 case MFEMUL_AUTH1:{
2597 if( len != 8) {
2598 cardSTATE_TO_IDLE();
2599 LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parity, TRUE);
2600 break;
2601 }
2602
2603 uint32_t nr = bytes_to_num(receivedCmd, 4);
2604 uint32_t ar = bytes_to_num(&receivedCmd[4], 4);
2605
2606 // Collect AR/NR per keytype & sector
2607 if(flags & FLAG_NR_AR_ATTACK) {
2608 for (uint8_t i = 0; i < ATTACK_KEY_COUNT; i++) {
2609 if ( ar_nr_collected[i+mM]==0 || ((cardAUTHSC == ar_nr_resp[i+mM].sector) && (cardAUTHKEY == ar_nr_resp[i+mM].keytype) && (ar_nr_collected[i+mM] > 0)) ) {
2610 // if first auth for sector, or matches sector and keytype of previous auth
2611 if (ar_nr_collected[i+mM] < 2) {
2612 // if we haven't already collected 2 nonces for this sector
2613 if (ar_nr_resp[ar_nr_collected[i+mM]].ar != ar) {
2614 // Avoid duplicates... probably not necessary, ar should vary.
2615 if (ar_nr_collected[i+mM]==0) {
2616 // first nonce collect
2617 ar_nr_resp[i+mM].cuid = cuid;
2618 ar_nr_resp[i+mM].sector = cardAUTHSC;
2619 ar_nr_resp[i+mM].keytype = cardAUTHKEY;
2620 ar_nr_resp[i+mM].nonce = nonce;
2621 ar_nr_resp[i+mM].nr = nr;
2622 ar_nr_resp[i+mM].ar = ar;
2623 nonce1_count++;
2624 // add this nonce to first moebius nonce
2625 ar_nr_resp[i+ATTACK_KEY_COUNT].cuid = cuid;
2626 ar_nr_resp[i+ATTACK_KEY_COUNT].sector = cardAUTHSC;
2627 ar_nr_resp[i+ATTACK_KEY_COUNT].keytype = cardAUTHKEY;
2628 ar_nr_resp[i+ATTACK_KEY_COUNT].nonce = nonce;
2629 ar_nr_resp[i+ATTACK_KEY_COUNT].nr = nr;
2630 ar_nr_resp[i+ATTACK_KEY_COUNT].ar = ar;
2631 ar_nr_collected[i+ATTACK_KEY_COUNT]++;
2632 } else { // second nonce collect (std and moebius)
2633 ar_nr_resp[i+mM].nonce2 = nonce;
2634 ar_nr_resp[i+mM].nr2 = nr;
2635 ar_nr_resp[i+mM].ar2 = ar;
2636 if (!gettingMoebius) {
2637 nonce2_count++;
2638 // check if this was the last second nonce we need for std attack
2639 if ( nonce2_count == nonce1_count ) {
2640 // done collecting std test switch to moebius
2641 // first finish incrementing last sample
2642 ar_nr_collected[i+mM]++;
2643 // switch to moebius collection
2644 gettingMoebius = true;
2645 mM = ATTACK_KEY_COUNT;
2646 if (flags & FLAG_RANDOM_NONCE) {
2647 nonce = prand();
2648 } else {
2649 nonce = nonce*7;
2650 }
2651 break;
2652 }
2653 } else {
2654 moebius_n_count++;
2655 // if we've collected all the nonces we need - finish.
2656 if (nonce1_count == moebius_n_count) finished = true;
2657 }
2658 }
2659 ar_nr_collected[i+mM]++;
2660 }
2661 }
2662 // we found right spot for this nonce stop looking
2663 break;
2664 }
2665 }
2666 }
2667
2668 // --- crypto
2669 crypto1_word(pcs, nr , 1);
2670 cardRr = ar ^ crypto1_word(pcs, 0, 0);
2671
2672 // test if auth OK
2673 if (cardRr != prng_successor(nonce, 64)){
2674 if (MF_DBGLEVEL >= 2) Dbprintf("AUTH FAILED for sector %d with key %c. cardRr=%08x, succ=%08x",
2675 cardAUTHSC, cardAUTHKEY == 0 ? 'A' : 'B',
2676 cardRr, prng_successor(nonce, 64));
2677 // Shouldn't we respond anything here?
2678 // Right now, we don't nack or anything, which causes the
2679 // reader to do a WUPA after a while. /Martin
2680 // -- which is the correct response. /piwi
2681 cardSTATE_TO_IDLE();
2682 LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parity, TRUE);
2683 break;
2684 }
2685
2686 //auth successful
2687 ans = prng_successor(nonce, 96) ^ crypto1_word(pcs, 0, 0);
2688
2689 num_to_bytes(ans, 4, rAUTH_AT);
2690 // --- crypto
2691 EmSendCmd(rAUTH_AT, sizeof(rAUTH_AT));
2692 LED_C_ON();
2693 cardSTATE = MFEMUL_WORK;
2694 if (MF_DBGLEVEL >= 4) Dbprintf("AUTH COMPLETED for sector %d with key %c. time=%d",
2695 cardAUTHSC, cardAUTHKEY == 0 ? 'A' : 'B',
2696 GetTickCount() - authTimer);
2697 break;
2698 }
2699 case MFEMUL_SELECT2:{
2700 if (!len) {
2701 LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parity, TRUE);
2702 break;
2703 }
2704 // select all cl2 - 0x95 0x20
2705 if (len == 2 && (receivedCmd[0] == ISO14443A_CMD_ANTICOLL_OR_SELECT_2 && receivedCmd[1] == 0x20)) {
2706 EmSendCmd(rUIDBCC2, sizeof(rUIDBCC2));
2707 break;
2708 }
2709
2710 // select cl2 card - 0x95 0x70 xxxxxxxxxxxx
2711 if (len == 9 &&
2712 (receivedCmd[0] == ISO14443A_CMD_ANTICOLL_OR_SELECT_2 && receivedCmd[1] == 0x70 && memcmp(&receivedCmd[2], rUIDBCC2, 4) == 0)) {
2713 switch(_UID_LEN) {
2714 case 7:
2715 EmSendCmd(rSAKfinal, sizeof(rSAKfinal));
2716 cardSTATE = MFEMUL_WORK;
2717 LED_B_ON();
2718 if (MF_DBGLEVEL >= 4) Dbprintf("--> WORK. anticol2 time: %d", GetTickCount() - selTimer);
2719 break;
2720 case 10:
2721 EmSendCmd(rSAK1, sizeof(rSAK1));
2722 cardSTATE = MFEMUL_SELECT3;
2723 break;
2724 default:break;
2725 }
2726 break;
2727 }
2728
2729 // i guess there is a command). go into the work state.
2730 if (len != 4) {
2731 LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parity, TRUE);
2732 break;
2733 }
2734 cardSTATE = MFEMUL_WORK;
2735 //goto lbWORK;
2736 //intentional fall-through to the next case-stmt
2737 }
2738
2739 case MFEMUL_WORK:{
2740 if (len == 0) {
2741 LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parity, TRUE);
2742 break;
2743 }
2744
2745 bool encrypted_data = (cardAUTHKEY != 0xFF) ;
2746
2747 if(encrypted_data) {
2748 // decrypt seqence
2749 mf_crypto1_decrypt(pcs, receivedCmd, len);
2750 }
2751
2752 if (len == 4 && (receivedCmd[0] == 0x60 || receivedCmd[0] == 0x61)) {
2753
2754 // if authenticating to a block that shouldn't exist - as long as we are not doing the reader attack
2755 if (receivedCmd[1] >= 16 * 4 && !(flags & FLAG_NR_AR_ATTACK)) {
2756 //is this the correct response to an auth on a out of range block? marshmellow
2757 EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_NACK_NA));
2758 if (MF_DBGLEVEL >= 2) Dbprintf("Reader tried to operate (0x%02x) on out of range block: %d (0x%02x), nacking",receivedCmd[0],receivedCmd[1],receivedCmd[1]);
2759 break;
2760 }
2761
2762 authTimer = GetTickCount();
2763 cardAUTHSC = receivedCmd[1] / 4; // received block num
2764 cardAUTHKEY = receivedCmd[0] - 0x60;
2765 crypto1_destroy(pcs);//Added by martin
2766 crypto1_create(pcs, emlGetKey(cardAUTHSC, cardAUTHKEY));
2767 //uint64_t key=emlGetKey(cardAUTHSC, cardAUTHKEY);
2768 //Dbprintf("key: %04x%08x",(uint32_t)(key>>32)&0xFFFF,(uint32_t)(key&0xFFFFFFFF));
2769
2770 if (!encrypted_data) { // first authentication
2771 if (MF_DBGLEVEL >= 4) Dbprintf("Reader authenticating for block %d (0x%02x) with key %d",receivedCmd[1] ,receivedCmd[1],cardAUTHKEY );
2772
2773 crypto1_word(pcs, cuid ^ nonce, 0);//Update crypto state
2774 num_to_bytes(nonce, 4, rAUTH_AT); // Send nonce
2775 } else { // nested authentication
2776 if (MF_DBGLEVEL >= 4) Dbprintf("Reader doing nested authentication for block %d (0x%02x) with key %d",receivedCmd[1] ,receivedCmd[1],cardAUTHKEY );
2777 ans = nonce ^ crypto1_word(pcs, cuid ^ nonce, 0);
2778 num_to_bytes(ans, 4, rAUTH_AT);
2779 }
2780
2781 EmSendCmd(rAUTH_AT, sizeof(rAUTH_AT));
2782 //Dbprintf("Sending rAUTH %02x%02x%02x%02x", rAUTH_AT[0],rAUTH_AT[1],rAUTH_AT[2],rAUTH_AT[3]);
2783 cardSTATE = MFEMUL_AUTH1;
2784 break;
2785 }
2786
2787 // rule 13 of 7.5.3. in ISO 14443-4. chaining shall be continued
2788 // BUT... ACK --> NACK
2789 if (len == 1 && receivedCmd[0] == CARD_ACK) {
2790 EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_NACK_NA));
2791 break;
2792 }
2793
2794 // rule 12 of 7.5.3. in ISO 14443-4. R(NAK) --> R(ACK)
2795 if (len == 1 && receivedCmd[0] == CARD_NACK_NA) {
2796 EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_ACK));
2797 break;
2798 }
2799
2800 if(len != 4) {
2801 LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parity, TRUE);
2802 break;
2803 }
2804
2805 if(receivedCmd[0] == 0x30 // read block
2806 || receivedCmd[0] == 0xA0 // write block
2807 || receivedCmd[0] == 0xC0 // inc
2808 || receivedCmd[0] == 0xC1 // dec
2809 || receivedCmd[0] == 0xC2 // restore
2810 || receivedCmd[0] == 0xB0) { // transfer
2811 if (receivedCmd[1] >= 16 * 4) {
2812 EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_NACK_NA));
2813 if (MF_DBGLEVEL >= 2) Dbprintf("Reader tried to operate (0x%02x) on out of range block: %d (0x%02x), nacking",receivedCmd[0],receivedCmd[1],receivedCmd[1]);
2814 break;
2815 }
2816
2817 if (receivedCmd[1] / 4 != cardAUTHSC) {
2818 EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_NACK_NA));
2819 if (MF_DBGLEVEL >= 2) Dbprintf("Reader tried to operate (0x%02x) on block (0x%02x) not authenticated for (0x%02x), nacking",receivedCmd[0],receivedCmd[1],cardAUTHSC);
2820 break;
2821 }
2822 }
2823 // read block
2824 if (receivedCmd[0] == 0x30) {
2825 if (MF_DBGLEVEL >= 4) {
2826 Dbprintf("Reader reading block %d (0x%02x)",receivedCmd[1],receivedCmd[1]);
2827 }
2828 emlGetMem(response, receivedCmd[1], 1);
2829 AppendCrc14443a(response, 16);
2830 mf_crypto1_encrypt(pcs, response, 18, response_par);
2831 EmSendCmdPar(response, 18, response_par);
2832 numReads++;
2833 if(exitAfterNReads > 0 && numReads == exitAfterNReads) {
2834 Dbprintf("%d reads done, exiting", numReads);
2835 finished = true;
2836 }
2837 break;
2838 }
2839 // write block
2840 if (receivedCmd[0] == 0xA0) {
2841 if (MF_DBGLEVEL >= 4) Dbprintf("RECV 0xA0 write block %d (%02x)",receivedCmd[1],receivedCmd[1]);
2842 EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_ACK));
2843 cardSTATE = MFEMUL_WRITEBL2;
2844 cardWRBL = receivedCmd[1];
2845 break;
2846 }
2847 // increment, decrement, restore
2848 if (receivedCmd[0] == 0xC0 || receivedCmd[0] == 0xC1 || receivedCmd[0] == 0xC2) {
2849 if (MF_DBGLEVEL >= 4) Dbprintf("RECV 0x%02x inc(0xC1)/dec(0xC0)/restore(0xC2) block %d (%02x)",receivedCmd[0],receivedCmd[1],receivedCmd[1]);
2850 if (emlCheckValBl(receivedCmd[1])) {
2851 if (MF_DBGLEVEL >= 2) Dbprintf("Reader tried to operate on block, but emlCheckValBl failed, nacking");
2852 EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_NACK_NA));
2853 break;
2854 }
2855 EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_ACK));
2856 if (receivedCmd[0] == 0xC1)
2857 cardSTATE = MFEMUL_INTREG_INC;
2858 if (receivedCmd[0] == 0xC0)
2859 cardSTATE = MFEMUL_INTREG_DEC;
2860 if (receivedCmd[0] == 0xC2)
2861 cardSTATE = MFEMUL_INTREG_REST;
2862 cardWRBL = receivedCmd[1];
2863 break;
2864 }
2865 // transfer
2866 if (receivedCmd[0] == 0xB0) {
2867 if (MF_DBGLEVEL >= 4) Dbprintf("RECV 0x%02x transfer block %d (%02x)",receivedCmd[0],receivedCmd[1],receivedCmd[1]);
2868 if (emlSetValBl(cardINTREG, cardINTBLOCK, receivedCmd[1]))
2869 EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_NACK_NA));
2870 else
2871 EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_ACK));
2872 break;
2873 }
2874 // halt
2875 if (receivedCmd[0] == 0x50 && receivedCmd[1] == 0x00) {
2876 LED_B_OFF();
2877 LED_C_OFF();
2878 cardSTATE = MFEMUL_HALTED;
2879 if (MF_DBGLEVEL >= 4) Dbprintf("--> HALTED. Selected time: %d ms", GetTickCount() - selTimer);
2880 LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parity, TRUE);
2881 break;
2882 }
2883 // RATS
2884 if (receivedCmd[0] == 0xe0) {//RATS
2885 EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_NACK_NA));
2886 break;
2887 }
2888 // command not allowed
2889 if (MF_DBGLEVEL >= 4) Dbprintf("Received command not allowed, nacking");
2890 EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_NACK_NA));
2891 break;
2892 }
2893 case MFEMUL_WRITEBL2:{
2894 if (len == 18){
2895 mf_crypto1_decrypt(pcs, receivedCmd, len);
2896 emlSetMem(receivedCmd, cardWRBL, 1);
2897 EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_ACK));
2898 cardSTATE = MFEMUL_WORK;
2899 } else {
2900 cardSTATE_TO_IDLE();
2901 LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parity, TRUE);
2902 }
2903 break;
2904 }
2905
2906 case MFEMUL_INTREG_INC:{
2907 mf_crypto1_decrypt(pcs, receivedCmd, len);
2908 memcpy(&ans, receivedCmd, 4);
2909 if (emlGetValBl(&cardINTREG, &cardINTBLOCK, cardWRBL)) {
2910 EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_NACK_NA));
2911 cardSTATE_TO_IDLE();
2912 break;
2913 }
2914 LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parity, TRUE);
2915 cardINTREG = cardINTREG + ans;
2916 cardSTATE = MFEMUL_WORK;
2917 break;
2918 }
2919 case MFEMUL_INTREG_DEC:{
2920 mf_crypto1_decrypt(pcs, receivedCmd, len);
2921 memcpy(&ans, receivedCmd, 4);
2922 if (emlGetValBl(&cardINTREG, &cardINTBLOCK, cardWRBL)) {
2923 EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_NACK_NA));
2924 cardSTATE_TO_IDLE();
2925 break;
2926 }
2927 LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parity, TRUE);
2928 cardINTREG = cardINTREG - ans;
2929 cardSTATE = MFEMUL_WORK;
2930 break;
2931 }
2932 case MFEMUL_INTREG_REST:{
2933 mf_crypto1_decrypt(pcs, receivedCmd, len);
2934 memcpy(&ans, receivedCmd, 4);
2935 if (emlGetValBl(&cardINTREG, &cardINTBLOCK, cardWRBL)) {
2936 EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_NACK_NA));
2937 cardSTATE_TO_IDLE();
2938 break;
2939 }
2940 LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parity, TRUE);
2941 cardSTATE = MFEMUL_WORK;
2942 break;
2943 }
2944 }
2945 button_pushed = BUTTON_PRESS();
2946 }
2947
2948 FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
2949 LEDsoff();
2950
2951 if(flags & FLAG_NR_AR_ATTACK && MF_DBGLEVEL >= 1) {
2952 for ( uint8_t i = 0; i < ATTACK_KEY_COUNT; i++) {
2953 if (ar_nr_collected[i] == 2) {
2954 Dbprintf("Collected two pairs of AR/NR which can be used to extract %s from reader for sector %d:", (i<ATTACK_KEY_COUNT/2) ? "keyA" : "keyB", ar_nr_resp[i].sector);
2955 Dbprintf("../tools/mfkey/mfkey32 %08x %08x %08x %08x %08x %08x",
2956 ar_nr_resp[i].cuid, //UID
2957 ar_nr_resp[i].nonce, //NT
2958 ar_nr_resp[i].nr, //NR1
2959 ar_nr_resp[i].ar, //AR1
2960 ar_nr_resp[i].nr2, //NR2
2961 ar_nr_resp[i].ar2 //AR2
2962 );
2963 }
2964 }
2965 for ( uint8_t i = ATTACK_KEY_COUNT; i < ATTACK_KEY_COUNT*2; i++) {
2966 if (ar_nr_collected[i] == 2) {
2967 Dbprintf("Collected two pairs of AR/NR which can be used to extract %s from reader for sector %d:", (i<ATTACK_KEY_COUNT/2) ? "keyA" : "keyB", ar_nr_resp[i].sector);
2968 Dbprintf("../tools/mfkey/mfkey32v2 %08x %08x %08x %08x %08x %08x %08x",
2969 ar_nr_resp[i].cuid, //UID
2970 ar_nr_resp[i].nonce, //NT
2971 ar_nr_resp[i].nr, //NR1
2972 ar_nr_resp[i].ar, //AR1
2973 ar_nr_resp[i].nonce2,//NT2
2974 ar_nr_resp[i].nr2, //NR2
2975 ar_nr_resp[i].ar2 //AR2
2976 );
2977 }
2978 }
2979 }
2980 if (MF_DBGLEVEL >= 1) Dbprintf("Emulator stopped. Tracing: %d trace length: %d ", tracing, BigBuf_get_traceLen());
2981
2982 if(flags & FLAG_INTERACTIVE) { // Interactive mode flag, means we need to send ACK
2983 //Send the collected ar_nr in the response
2984 cmd_send(CMD_ACK,CMD_SIMULATE_MIFARE_CARD,button_pushed,0,&ar_nr_resp,sizeof(ar_nr_resp));
2985 }
2986 }
2987
2988
2989 //-----------------------------------------------------------------------------
2990 // MIFARE sniffer.
2991 //
2992 //-----------------------------------------------------------------------------
2993 void RAMFUNC SniffMifare(uint8_t param) {
2994 // param:
2995 // bit 0 - trigger from first card answer
2996 // bit 1 - trigger from first reader 7-bit request
2997
2998 // C(red) A(yellow) B(green)
2999 LEDsoff();
3000 // init trace buffer
3001 clear_trace();
3002 set_tracing(TRUE);
3003
3004 // The command (reader -> tag) that we're receiving.
3005 // The length of a received command will in most cases be no more than 18 bytes.
3006 // So 32 should be enough!
3007 uint8_t receivedCmd[MAX_MIFARE_FRAME_SIZE];
3008 uint8_t receivedCmdPar[MAX_MIFARE_PARITY_SIZE];
3009 // The response (tag -> reader) that we're receiving.
3010 uint8_t receivedResponse[MAX_MIFARE_FRAME_SIZE];
3011 uint8_t receivedResponsePar[MAX_MIFARE_PARITY_SIZE];
3012
3013 iso14443a_setup(FPGA_HF_ISO14443A_SNIFFER);
3014
3015 // free eventually allocated BigBuf memory
3016 BigBuf_free();
3017 // allocate the DMA buffer, used to stream samples from the FPGA
3018 uint8_t *dmaBuf = BigBuf_malloc(DMA_BUFFER_SIZE);
3019 uint8_t *data = dmaBuf;
3020 uint8_t previous_data = 0;
3021 int maxDataLen = 0;
3022 int dataLen = 0;
3023 bool ReaderIsActive = FALSE;
3024 bool TagIsActive = FALSE;
3025
3026 // Set up the demodulator for tag -> reader responses.
3027 DemodInit(receivedResponse, receivedResponsePar);
3028
3029 // Set up the demodulator for the reader -> tag commands
3030 UartInit(receivedCmd, receivedCmdPar);
3031
3032 // Setup for the DMA.
3033 FpgaSetupSscDma((uint8_t *)dmaBuf, DMA_BUFFER_SIZE); // set transfer address and number of bytes. Start transfer.
3034
3035 LED_D_OFF();
3036
3037 // init sniffer
3038 MfSniffInit();
3039
3040 // And now we loop, receiving samples.
3041 for(uint32_t sniffCounter = 0; TRUE; ) {
3042
3043 if(BUTTON_PRESS()) {
3044 DbpString("cancelled by button");
3045 break;
3046 }
3047
3048 LED_A_ON();
3049 WDT_HIT();
3050
3051 if ((sniffCounter & 0x0000FFFF) == 0) { // from time to time
3052 // check if a transaction is completed (timeout after 2000ms).
3053 // if yes, stop the DMA transfer and send what we have so far to the client
3054 if (MfSniffSend(2000)) {
3055 // Reset everything - we missed some sniffed data anyway while the DMA was stopped
3056 sniffCounter = 0;
3057 data = dmaBuf;
3058 maxDataLen = 0;
3059 ReaderIsActive = FALSE;
3060 TagIsActive = FALSE;
3061 FpgaSetupSscDma((uint8_t *)dmaBuf, DMA_BUFFER_SIZE); // set transfer address and number of bytes. Start transfer.
3062 }
3063 }
3064
3065 int register readBufDataP = data - dmaBuf; // number of bytes we have processed so far
3066 int register dmaBufDataP = DMA_BUFFER_SIZE - AT91C_BASE_PDC_SSC->PDC_RCR; // number of bytes already transferred
3067 if (readBufDataP <= dmaBufDataP){ // we are processing the same block of data which is currently being transferred
3068 dataLen = dmaBufDataP - readBufDataP; // number of bytes still to be processed
3069 } else {
3070 dataLen = DMA_BUFFER_SIZE - readBufDataP + dmaBufDataP; // number of bytes still to be processed
3071 }
3072 // test for length of buffer
3073 if(dataLen > maxDataLen) { // we are more behind than ever...
3074 maxDataLen = dataLen;
3075 if(dataLen > (9 * DMA_BUFFER_SIZE / 10)) {
3076 Dbprintf("blew circular buffer! dataLen=0x%x", dataLen);
3077 break;
3078 }
3079 }
3080 if(dataLen < 1) continue;
3081
3082 // primary buffer was stopped ( <-- we lost data!
3083 if (!AT91C_BASE_PDC_SSC->PDC_RCR) {
3084 AT91C_BASE_PDC_SSC->PDC_RPR = (uint32_t) dmaBuf;
3085 AT91C_BASE_PDC_SSC->PDC_RCR = DMA_BUFFER_SIZE;
3086 Dbprintf("RxEmpty ERROR!!! data length:%d", dataLen); // temporary
3087 }
3088 // secondary buffer sets as primary, secondary buffer was stopped
3089 if (!AT91C_BASE_PDC_SSC->PDC_RNCR) {
3090 AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) dmaBuf;
3091 AT91C_BASE_PDC_SSC->PDC_RNCR = DMA_BUFFER_SIZE;
3092 }
3093
3094 LED_A_OFF();
3095
3096 if (sniffCounter & 0x01) {
3097
3098 if(!TagIsActive) { // no need to try decoding tag data if the reader is sending
3099 uint8_t readerdata = (previous_data & 0xF0) | (*data >> 4);
3100 if(MillerDecoding(readerdata, (sniffCounter-1)*4)) {
3101 LED_C_INV();
3102 if (MfSniffLogic(receivedCmd, Uart.len, Uart.parity, Uart.bitCount, TRUE)) break;
3103
3104 /* And ready to receive another command. */
3105 UartInit(receivedCmd, receivedCmdPar);
3106
3107 /* And also reset the demod code */
3108 DemodReset();
3109 }
3110 ReaderIsActive = (Uart.state != STATE_UNSYNCD);
3111 }
3112
3113 if(!ReaderIsActive) { // no need to try decoding tag data if the reader is sending
3114 uint8_t tagdata = (previous_data << 4) | (*data & 0x0F);
3115 if(ManchesterDecoding(tagdata, 0, (sniffCounter-1)*4)) {
3116 LED_C_INV();
3117
3118 if (MfSniffLogic(receivedResponse, Demod.len, Demod.parity, Demod.bitCount, FALSE)) break;
3119
3120 // And ready to receive another response.
3121 DemodReset();
3122 // And reset the Miller decoder including its (now outdated) input buffer
3123 UartInit(receivedCmd, receivedCmdPar);
3124 }
3125 TagIsActive = (Demod.state != DEMOD_UNSYNCD);
3126 }
3127 }
3128
3129 previous_data = *data;
3130 sniffCounter++;
3131 data++;
3132 if(data == dmaBuf + DMA_BUFFER_SIZE) {
3133 data = dmaBuf;
3134 }
3135
3136 } // main cycle
3137
3138 DbpString("COMMAND FINISHED");
3139
3140 FpgaDisableSscDma();
3141 MfSniffEnd();
3142
3143 Dbprintf("maxDataLen=%x, Uart.state=%x, Uart.len=%x", maxDataLen, Uart.state, Uart.len);
3144 LEDsoff();
3145 }
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