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[proxmark3-svn] / armsrc / pcf7931.c
1 #include "proxmark3.h"
2 #include "apps.h"
3 #include "lfsampling.h"
4 #include "pcf7931.h"
5 #include "string.h"
6
7 #define T0_PCF 8 //period for the pcf7931 in us
8 #define ALLOC 16
9
10 int DemodPCF7931(uint8_t **outBlocks) {
11
12 uint8_t bits[256] = {0x00};
13 uint8_t blocks[8][16];
14 uint8_t *dest = BigBuf_get_addr();
15
16 int GraphTraceLen = BigBuf_max_traceLen();
17 if ( GraphTraceLen > 18000 )
18 GraphTraceLen = 18000;
19
20 int i, j, lastval, bitidx, half_switch;
21 int clock = 64;
22 int tolerance = clock / 8;
23 int pmc, block_done;
24 int lc, warnings = 0;
25 int num_blocks = 0;
26 int lmin=128, lmax=128;
27 uint8_t dir;
28 //clear read buffer
29 BigBuf_Clear_keep_EM();
30
31 LFSetupFPGAForADC(95, true);
32 DoAcquisition_default(0, true);
33
34 lmin = 64;
35 lmax = 192;
36
37 i = 2;
38
39 /* Find first local max/min */
40 if(dest[1] > dest[0]) {
41 while(i < GraphTraceLen) {
42 if( !(dest[i] > dest[i-1]) && dest[i] > lmax)
43 break;
44 i++;
45 }
46 dir = 0;
47 }
48 else {
49 while(i < GraphTraceLen) {
50 if( !(dest[i] < dest[i-1]) && dest[i] < lmin)
51 break;
52 i++;
53 }
54 dir = 1;
55 }
56
57 lastval = i++;
58 half_switch = 0;
59 pmc = 0;
60 block_done = 0;
61
62 for (bitidx = 0; i < GraphTraceLen; i++)
63 {
64 if ( (dest[i-1] > dest[i] && dir == 1 && dest[i] > lmax) || (dest[i-1] < dest[i] && dir == 0 && dest[i] < lmin))
65 {
66 lc = i - lastval;
67 lastval = i;
68
69 // Switch depending on lc length:
70 // Tolerance is 1/8 of clock rate (arbitrary)
71 if (ABS(lc-clock/4) < tolerance) {
72 // 16T0
73 if((i - pmc) == lc) { /* 16T0 was previous one */
74 /* It's a PMC ! */
75 i += (128+127+16+32+33+16)-1;
76 lastval = i;
77 pmc = 0;
78 block_done = 1;
79 }
80 else {
81 pmc = i;
82 }
83 } else if (ABS(lc-clock/2) < tolerance) {
84 // 32TO
85 if((i - pmc) == lc) { /* 16T0 was previous one */
86 /* It's a PMC ! */
87 i += (128+127+16+32+33)-1;
88 lastval = i;
89 pmc = 0;
90 block_done = 1;
91 }
92 else if(half_switch == 1) {
93 bits[bitidx++] = 0;
94 half_switch = 0;
95 }
96 else
97 half_switch++;
98 } else if (ABS(lc-clock) < tolerance) {
99 // 64TO
100 bits[bitidx++] = 1;
101 } else {
102 // Error
103 warnings++;
104 if (warnings > 10)
105 {
106 Dbprintf("Error: too many detection errors, aborting.");
107 return 0;
108 }
109 }
110
111 if(block_done == 1) {
112 if(bitidx == 128) {
113 for(j=0; j<16; j++) {
114 blocks[num_blocks][j] = 128*bits[j*8+7]+
115 64*bits[j*8+6]+
116 32*bits[j*8+5]+
117 16*bits[j*8+4]+
118 8*bits[j*8+3]+
119 4*bits[j*8+2]+
120 2*bits[j*8+1]+
121 bits[j*8];
122
123 }
124 num_blocks++;
125 }
126 bitidx = 0;
127 block_done = 0;
128 half_switch = 0;
129 }
130 if(i < GraphTraceLen)
131 dir =(dest[i-1] > dest[i]) ? 0 : 1;
132 }
133 if(bitidx==255)
134 bitidx=0;
135 warnings = 0;
136 if(num_blocks == 4) break;
137 }
138 memcpy(outBlocks, blocks, 16*num_blocks);
139 return num_blocks;
140 }
141
142 int IsBlock0PCF7931(uint8_t *Block) {
143 // Assume RFU means 0 :)
144 if((memcmp(Block, "\x00\x00\x00\x00\x00\x00\x00\x01", 8) == 0) && memcmp(Block+9, "\x00\x00\x00\x00\x00\x00\x00", 7) == 0) // PAC enabled
145 return 1;
146 if((memcmp(Block+9, "\x00\x00\x00\x00\x00\x00\x00", 7) == 0) && Block[7] == 0) // PAC disabled, can it *really* happen ?
147 return 1;
148 return 0;
149 }
150
151 int IsBlock1PCF7931(uint8_t *Block) {
152 // Assume RFU means 0 :)
153 if( Block[10] == 0 &&
154 Block[11] == 0 &&
155 Block[12] == 0 &&
156 Block[13] == 0)
157 if ( (Block[14] & 0x7f) <= 9 && Block[15] <= 9)
158 return 1;
159 return 0;
160 }
161
162 void ReadPCF7931() {
163 uint8_t Blocks[8][17];
164 uint8_t tmpBlocks[4][16];
165 int i, j, ind, ind2, n;
166 int num_blocks = 0;
167 int max_blocks = 8;
168 int ident = 0;
169 int error = 0;
170 int tries = 0;
171
172 memset(Blocks, 0, 8*17*sizeof(uint8_t));
173
174 do {
175 memset(tmpBlocks, 0, 4*16*sizeof(uint8_t));
176 n = DemodPCF7931((uint8_t**)tmpBlocks);
177 if(!n)
178 error++;
179 if(error==10 && num_blocks == 0) {
180 Dbprintf("Error, no tag or bad tag");
181 return;
182 }
183 else if (tries==20 || error==10) {
184 Dbprintf("Error reading the tag");
185 Dbprintf("Here is the partial content");
186 goto end;
187 }
188
189 for(i=0; i<n; i++)
190 Dbprintf("(dbg) %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x",
191 tmpBlocks[i][0], tmpBlocks[i][1], tmpBlocks[i][2], tmpBlocks[i][3], tmpBlocks[i][4], tmpBlocks[i][5], tmpBlocks[i][6], tmpBlocks[i][7],
192 tmpBlocks[i][8], tmpBlocks[i][9], tmpBlocks[i][10], tmpBlocks[i][11], tmpBlocks[i][12], tmpBlocks[i][13], tmpBlocks[i][14], tmpBlocks[i][15]);
193 if(!ident) {
194 for(i=0; i<n; i++) {
195 if(IsBlock0PCF7931(tmpBlocks[i])) {
196 // Found block 0 ?
197 if(i < n-1 && IsBlock1PCF7931(tmpBlocks[i+1])) {
198 // Found block 1!
199 // \o/
200 ident = 1;
201 memcpy(Blocks[0], tmpBlocks[i], 16);
202 Blocks[0][ALLOC] = 1;
203 memcpy(Blocks[1], tmpBlocks[i+1], 16);
204 Blocks[1][ALLOC] = 1;
205 max_blocks = MAX((Blocks[1][14] & 0x7f), Blocks[1][15]) + 1;
206 // Debug print
207 Dbprintf("(dbg) Max blocks: %d", max_blocks);
208 num_blocks = 2;
209 // Handle following blocks
210 for(j=i+2, ind2=2; j!=i; j++, ind2++, num_blocks++) {
211 if(j==n) j=0;
212 if(j==i) break;
213 memcpy(Blocks[ind2], tmpBlocks[j], 16);
214 Blocks[ind2][ALLOC] = 1;
215 }
216 break;
217 }
218 }
219 }
220 }
221 else {
222 for(i=0; i<n; i++) { // Look for identical block in known blocks
223 if(memcmp(tmpBlocks[i], "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", 16)) { // Block is not full of 00
224 for(j=0; j<max_blocks; j++) {
225 if(Blocks[j][ALLOC] == 1 && !memcmp(tmpBlocks[i], Blocks[j], 16)) {
226 // Found an identical block
227 for(ind=i-1,ind2=j-1; ind >= 0; ind--,ind2--) {
228 if(ind2 < 0)
229 ind2 = max_blocks;
230 if(!Blocks[ind2][ALLOC]) { // Block ind2 not already found
231 // Dbprintf("Tmp %d -> Block %d", ind, ind2);
232 memcpy(Blocks[ind2], tmpBlocks[ind], 16);
233 Blocks[ind2][ALLOC] = 1;
234 num_blocks++;
235 if(num_blocks == max_blocks) goto end;
236 }
237 }
238 for(ind=i+1,ind2=j+1; ind < n; ind++,ind2++) {
239 if(ind2 > max_blocks)
240 ind2 = 0;
241 if(!Blocks[ind2][ALLOC]) { // Block ind2 not already found
242 // Dbprintf("Tmp %d -> Block %d", ind, ind2);
243 memcpy(Blocks[ind2], tmpBlocks[ind], 16);
244 Blocks[ind2][ALLOC] = 1;
245 num_blocks++;
246 if(num_blocks == max_blocks) goto end;
247 }
248 }
249 }
250 }
251 }
252 }
253 }
254 tries++;
255 if (BUTTON_PRESS()) return;
256 } while (num_blocks != max_blocks);
257 end:
258 Dbprintf("-----------------------------------------");
259 Dbprintf("Memory content:");
260 Dbprintf("-----------------------------------------");
261 for(i=0; i<max_blocks; i++) {
262 if(Blocks[i][ALLOC]==1)
263 Dbprintf("%02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x",
264 Blocks[i][0], Blocks[i][1], Blocks[i][2], Blocks[i][3], Blocks[i][4], Blocks[i][5], Blocks[i][6], Blocks[i][7],
265 Blocks[i][8], Blocks[i][9], Blocks[i][10], Blocks[i][11], Blocks[i][12], Blocks[i][13], Blocks[i][14], Blocks[i][15]);
266 else
267 Dbprintf("<missing block %d>", i);
268 }
269 Dbprintf("-----------------------------------------");
270
271 cmd_send(CMD_ACK,0,0,0,0,0);
272 }
273
274
275 /* Write on a byte of a PCF7931 tag
276 * @param address : address of the block to write
277 @param byte : address of the byte to write
278 @param data : data to write
279 */
280 void WritePCF7931(uint8_t pass1, uint8_t pass2, uint8_t pass3, uint8_t pass4, uint8_t pass5, uint8_t pass6, uint8_t pass7, uint16_t init_delay, int32_t l, int32_t p, uint8_t address, uint8_t byte, uint8_t data)
281 {
282 uint32_t tab[1024] = {0}; // data times frame
283 uint32_t u = 0;
284 uint8_t parity = 0;
285 bool comp = 0;
286
287 //BUILD OF THE DATA FRAME
288
289 //alimentation of the tag (time for initializing)
290 AddPatternPCF7931(init_delay, 0, 8192/2*T0_PCF, tab);
291
292 //PMC
293 Dbprintf("Initialization delay : %d us", init_delay);
294 AddPatternPCF7931(8192/2*T0_PCF + 319*T0_PCF+70, 3*T0_PCF, 29*T0_PCF, tab);
295
296 Dbprintf("Offsets : %d us on the low pulses width, %d us on the low pulses positions", l, p);
297
298 //password indication bit
299 AddBitPCF7931(1, tab, l, p);
300
301 //password (on 56 bits)
302 Dbprintf("Password (LSB first on each byte) : %02x %02x %02x %02x %02x %02x %02x", pass1,pass2,pass3,pass4,pass5,pass6,pass7);
303 AddBytePCF7931(pass1, tab, l, p);
304 AddBytePCF7931(pass2, tab, l, p);
305 AddBytePCF7931(pass3, tab, l, p);
306 AddBytePCF7931(pass4, tab, l, p);
307 AddBytePCF7931(pass5, tab, l, p);
308 AddBytePCF7931(pass6, tab, l, p);
309 AddBytePCF7931(pass7, tab, l, p);
310
311
312 //programming mode (0 or 1)
313 AddBitPCF7931(0, tab, l, p);
314
315 //block adress on 6 bits
316 Dbprintf("Block address : %02x", address);
317 for (u=0; u<6; u++)
318 {
319 if (address&(1<<u)) { // bit 1
320 parity++;
321 AddBitPCF7931(1, tab, l, p);
322 } else{ // bit 0
323 AddBitPCF7931(0, tab, l, p);
324 }
325 }
326
327 //byte address on 4 bits
328 Dbprintf("Byte address : %02x", byte);
329 for (u=0; u<4; u++)
330 {
331 if (byte&(1<<u)) { // bit 1
332 parity++;
333 AddBitPCF7931(1, tab, l, p);
334 } else{ // bit 0
335 AddBitPCF7931(0, tab, l, p);
336 }
337 }
338
339 //data on 8 bits
340 Dbprintf("Data : %02x", data);
341 for (u=0; u<8; u++)
342 {
343 if (data&(1<<u)) { // bit 1
344 parity++;
345 AddBitPCF7931(1, tab, l, p);
346 } else{ //bit 0
347 AddBitPCF7931(0, tab, l, p);
348 }
349 }
350
351
352 //parity bit
353 if((parity%2)==0){
354 AddBitPCF7931(0, tab, l, p); //even parity
355 }else{
356 AddBitPCF7931(1, tab, l, p);//odd parity
357 }
358
359 //time access memory
360 AddPatternPCF7931(5120+2680, 0, 0, tab);
361
362 //conversion of the scale time
363 for(u=0;u<500;u++){
364 tab[u]=(tab[u] * 3)/2;
365 }
366
367 //compensation of the counter reload
368 while (!comp){
369 comp = 1;
370 for(u=0;tab[u]!=0;u++){
371 if(tab[u] > 0xFFFF){
372 tab[u] -= 0xFFFF;
373 comp = 0;
374 }
375 }
376 }
377
378 SendCmdPCF7931(tab);
379 }
380
381
382
383 /* Send a trame to a PCF7931 tags
384 * @param tab : array of the data frame
385 */
386
387 void SendCmdPCF7931(uint32_t * tab){
388 uint16_t u=0, tempo=0;
389
390 Dbprintf("Sending data frame...");
391
392 FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
393
394 FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
395
396 FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_PASSTHRU );
397
398 LED_A_ON();
399
400 // steal this pin from the SSP and use it to control the modulation
401 AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT;
402 AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
403
404 //initialization of the timer
405 AT91C_BASE_PMC->PMC_PCER |= (0x1 << AT91C_ID_TC0);
406 AT91C_BASE_TCB->TCB_BMR = AT91C_TCB_TC0XC0S_NONE | AT91C_TCB_TC1XC1S_TIOA0 | AT91C_TCB_TC2XC2S_NONE;
407 AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS; // timer disable
408 AT91C_BASE_TC0->TC_CMR = AT91C_TC_CLKS_TIMER_DIV3_CLOCK; //clock at 48/32 MHz
409 AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKEN;
410 AT91C_BASE_TCB->TCB_BCR = 1;
411
412
413 tempo = AT91C_BASE_TC0->TC_CV;
414 for( u = 0; tab[u] != 0; u += 3){
415
416 // modulate antenna
417 HIGH(GPIO_SSC_DOUT);
418 while(tempo != tab[u]) tempo = AT91C_BASE_TC0->TC_CV;
419
420 // stop modulating antenna
421 LOW(GPIO_SSC_DOUT);
422 while(tempo != tab[u+1]) tempo = AT91C_BASE_TC0->TC_CV;
423
424 // modulate antenna
425 HIGH(GPIO_SSC_DOUT);
426 while(tempo != tab[u+2]) tempo = AT91C_BASE_TC0->TC_CV;
427 }
428
429 LED_A_OFF();
430 FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
431 SpinDelay(200);
432
433 AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS; // timer disable
434 LED(0xFFFF, 1000);
435 }
436
437
438 /* Add a byte for building the data frame of PCF7931 tags
439 * @param b : byte to add
440 * @param tab : array of the data frame
441 * @param l : offset on low pulse width
442 * @param p : offset on low pulse positioning
443 */
444
445 bool AddBytePCF7931(uint8_t byte, uint32_t * tab, int32_t l, int32_t p){
446
447 uint32_t u;
448 for ( u=0; u<8; u++)
449 {
450 if (byte&(1<<u)) { //bit à 1
451 if( AddBitPCF7931(1, tab, l, p)==1) return 1;
452 } else { //bit à 0
453 if (AddBitPCF7931(0, tab, l, p)==1) return 1;
454 }
455 }
456 return 0;
457 }
458
459 /* Add a bits for building the data frame of PCF7931 tags
460 * @param b : bit to add
461 * @param tab : array of the data frame
462 * @param l : offset on low pulse width
463 * @param p : offset on low pulse positioning
464 */
465 bool AddBitPCF7931(bool b, uint32_t * tab, int32_t l, int32_t p){
466 uint8_t u = 0;
467
468 //we put the cursor at the last value of the array
469 for ( u = 0; tab[u] != 0; u += 3 ) { }
470
471 if ( b == 1 ) { //add a bit 1
472 if ( u == 0 )
473 tab[u] = 34 * T0_PCF + p;
474 else
475 tab[u] = 34 * T0_PCF + tab[u-1] + p;
476
477 tab[u+1] = 6 * T0_PCF + tab[u] + l;
478 tab[u+2] = 88 * T0_PCF + tab[u+1] - l - p;
479 return 0;
480 } else { //add a bit 0
481
482 if ( u == 0 )
483 tab[u] = 98 * T0_PCF + p;
484 else
485 tab[u] = 98 * T0_PCF + tab[u-1] + p;
486
487 tab[u+1] = 6 * T0_PCF + tab[u] + l;
488 tab[u+2] = 24 * T0_PCF + tab[u+1] - l - p;
489 return 0;
490 }
491 return 1;
492 }
493
494 /* Add a custom pattern in the data frame
495 * @param a : delay of the first high pulse
496 * @param b : delay of the low pulse
497 * @param c : delay of the last high pulse
498 * @param tab : array of the data frame
499 */
500 bool AddPatternPCF7931(uint32_t a, uint32_t b, uint32_t c, uint32_t * tab){
501 uint32_t u = 0;
502 for(u = 0; tab[u] != 0; u += 3){} //we put the cursor at the last value of the array
503
504 tab[u] = (u == 0) ? a : a + tab[u-1];
505 tab[u+1] = b + tab[u];
506 tab[u+2] = c + tab[u+1];
507
508 return 0;
509 }
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