[proxmark3-svn] / armsrc / pcf7931.c

#include "proxmark3.h"
#include "apps.h"
#include "lfsampling.h"
#include "pcf7931.h"
#include "util.h"
#include "string.h"
#include "fpgaloader.h"

#define T0_PCF 8 //period for the pcf7931 in us
#define ALLOC 16

size_t DemodPCF7931(uint8_t **outBlocks) {
	uint8_t bits[256] = {0x00};
	uint8_t blocks[8][16];
	uint8_t *dest = BigBuf_get_addr();
    
	int GraphTraceLen = BigBuf_max_traceLen();
	if (GraphTraceLen > 18000)
		GraphTraceLen = 18000;
	
	int i, j, lastval, bitidx, half_switch;
	int clock = 64;
	int tolerance = clock / 8;
	int pmc, block_done;
	int lc, warnings = 0;
	size_t num_blocks = 0;
	int lmin=128, lmax=128;
	uint8_t dir;
	//clear read buffer
	BigBuf_Clear_keep_EM();

	LFSetupFPGAForADC(95, true);
	DoAcquisition_default(0, true);

	lmin = 64;
	lmax = 192;

	i = 2;

	/* Find first local max/min */
	if(dest[1] > dest[0]) {
		while(i < GraphTraceLen) {
			if( !(dest[i] > dest[i-1]) && dest[i] > lmax)
				break;
			i++;
		}
		dir = 0;
	} else {
		while(i < GraphTraceLen) {
			if( !(dest[i] < dest[i-1]) && dest[i] < lmin)
				break;
			i++;
		}
		dir = 1;
	}

	lastval = i++;
	half_switch = 0;
	pmc = 0;
	block_done = 0;

	for (bitidx = 0; i < GraphTraceLen; i++) {
		if ((dest[i-1] > dest[i] && dir == 1 && dest[i] > lmax) || (dest[i-1] < dest[i] && dir == 0 && dest[i] < lmin)) {
			lc = i - lastval;
			lastval = i;

			// Switch depending on lc length:
			// Tolerance is 1/8 of clock rate (arbitrary)
			if (ABS(lc-clock/4) < tolerance) {
				// 16T0
				if((i - pmc) == lc) { /* 16T0 was previous one */
					/* It's a PMC ! */
					i += (128+127+16+32+33+16)-1;
					lastval = i;
					pmc = 0;
					block_done = 1;
				} else {
					pmc = i;
				}
			} else if (ABS(lc-clock/2) < tolerance) {
				// 32TO
				if((i - pmc) == lc) { /* 16T0 was previous one */
					/* It's a PMC ! */
					i += (128+127+16+32+33)-1;
					lastval = i;
					pmc = 0;
					block_done = 1;
				} else if(half_switch == 1) {
					bits[bitidx++] = 0;
					half_switch = 0;
				}
				else
					half_switch++;
			} else if (ABS(lc-clock) < tolerance) {
				// 64TO
				bits[bitidx++] = 1;
			} else {
				// Error
				if (++warnings > 10) {
					Dbprintf("Error: too many detection errors, aborting.");
					return 0;
				}
			}

			if(block_done == 1) {
				if(bitidx == 128) {
					for(j = 0; j < 16; ++j) {
						blocks[num_blocks][j] =
							128 * bits[j*8 + 7]+
	                                		64 * bits[j*8 + 6] +
							32 * bits[j*8 + 5] +
							16 * bits[j*8 + 4] +
							8 * bits[j*8 + 3] +
							4 * bits[j*8 + 2] +
							2 * bits[j*8 + 1] +
							bits[j*8]
						;
					}
					num_blocks++;
				}
				bitidx = 0;
				block_done = 0;
				half_switch = 0;
			}
			if(i < GraphTraceLen)
				dir = (dest[i-1] > dest[i]) ? 0 : 1;
		}
		if(bitidx==255)
			bitidx=0;
		warnings = 0;
		if(num_blocks == 4) break;
	}
	memcpy(outBlocks, blocks, 16 * num_blocks);
	return num_blocks;
}

bool IsBlock0PCF7931(uint8_t *block) {
	// assuming all RFU bits are set to 0
	// if PAC is enabled password is set to 0
	if (block[7] == 0x01)
	{
		if (!memcmp(block, "\x00\x00\x00\x00\x00\x00\x00", 7) && !memcmp(block+9, "\x00\x00\x00\x00\x00\x00\x00", 7))
			return true;
	}
	else if (block[7] == 0x00)
	{
		if (!memcmp(block+9, "\x00\x00\x00\x00\x00\x00\x00", 7))
			return true;
	}
	return false;
}

bool IsBlock1PCF7931(uint8_t *block) {
	// assuming all RFU bits are set to 0
	if (block[10] == 0 && block[11] == 0 && block[12] == 0 && block[13] == 0)
		if((block[14] & 0x7f) <= 9 && block[15] <= 9)
			return true;

	return false;
}

void ReadPCF7931() {
	int found_blocks = 0; // successfully read blocks
	int max_blocks = 8;	// readable blocks	
	uint8_t memory_blocks[8][17]; // PCF content
	
	uint8_t single_blocks[8][17]; // PFC blocks with unknown position
	int single_blocks_cnt = 0;

	size_t n = 0; // transmitted blocks	
	uint8_t tmp_blocks[4][16]; // temporary read buffer
	
	uint8_t found_0_1 = 0; // flag: blocks 0 and 1 were found
	int errors = 0; // error counter
	int tries = 0; // tries counter
	
	memset(memory_blocks, 0, 8*17*sizeof(uint8_t));
	memset(single_blocks, 0, 8*17*sizeof(uint8_t));
	
	int i = 0, j = 0;

	do {
		i = 0;
		
		memset(tmp_blocks, 0, 4*16*sizeof(uint8_t));
		n = DemodPCF7931((uint8_t**)tmp_blocks);
		if(!n)
			++errors;
		
		// exit if no block is received 
		if (errors >= 10 && found_blocks == 0 && single_blocks_cnt == 0) {
			Dbprintf("Error, no tag or bad tag");
			return;
		}
		// exit if too many errors during reading 
		if (tries > 50 && (2*errors > tries)) {
			Dbprintf("Error reading the tag");
			Dbprintf("Here is the partial content");
			goto end;
		}
		
		// our logic breaks if we don't get at least two blocks
		if (n < 2) {
			if (n == 0 || !memcmp(tmp_blocks[0], "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", 16))
				continue;

			if (single_blocks_cnt < max_blocks) {
				for (i = 0; i < single_blocks_cnt; ++i) {
					if (!memcmp(single_blocks[i], tmp_blocks[0], 16)) {
						j = 1;
						break;
					}
				}
				if (j != 1) {
					memcpy(single_blocks[single_blocks_cnt], tmp_blocks[0], 16);
					single_blocks_cnt++;
				}
				j = 0;
			}
			++tries;
			continue;
	 	}
	 	
	 	Dbprintf("(dbg) got %d blocks (%d/%d found) (%d tries, %d errors)", n, found_blocks, (max_blocks == 0 ? found_blocks : max_blocks), tries, errors);

		i = 0;
		if(!found_0_1) {			
			while (i < n - 1) {
				if (IsBlock0PCF7931(tmp_blocks[i]) && IsBlock1PCF7931(tmp_blocks[i+1])) {
					found_0_1 = 1;
					memcpy(memory_blocks[0], tmp_blocks[i], 16);
					memcpy(memory_blocks[1], tmp_blocks[i+1], 16);
					memory_blocks[0][ALLOC] = memory_blocks[1][ALLOC] = 1;
					// block 1 tells how many blocks are going to be sent
					max_blocks = MAX((memory_blocks[1][14] & 0x7f), memory_blocks[1][15]) + 1;
					found_blocks = 2;
					
					Dbprintf("Found blocks 0 and 1. PCF is transmitting %d blocks.", max_blocks);
					
					// handle the following blocks
					for (j = i + 2; j < n; ++j) {
						memcpy(memory_blocks[found_blocks], tmp_blocks[j], 16);
						memory_blocks[found_blocks][ALLOC] = 1;
						++found_blocks;
					}
					break;
				}
				++i;
			}
		} else {
			// Trying to re-order blocks
			// Look for identical block in memory blocks
			while (i < n-1) {
				// skip all zeroes blocks
				if (memcmp(tmp_blocks[i], "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", 16)) {
					for (j = 1; j < max_blocks - 1; ++j) {
						if (!memcmp(tmp_blocks[i], memory_blocks[j], 16) && !memory_blocks[j+1][ALLOC]) {
							memcpy(memory_blocks[j+1], tmp_blocks[i+1], 16);
							memory_blocks[j+1][ALLOC] = 1;
							if (++found_blocks >= max_blocks) goto end;
						}
					}
				}
				if (memcmp(tmp_blocks[i+1], "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", 16)) {
					for (j = 0; j < max_blocks; ++j) {
						if (!memcmp(tmp_blocks[i+1], memory_blocks[j], 16) && !memory_blocks[(j == 0 ? max_blocks : j) -1][ALLOC]) {
							if (j == 0) {
								memcpy(memory_blocks[max_blocks - 1], tmp_blocks[i], 16);
								memory_blocks[max_blocks - 1][ALLOC] = 1;
							} else {
								memcpy(memory_blocks[j-1], tmp_blocks[i], 16);
								memory_blocks[j-1][ALLOC] = 1;
							}
							if (++found_blocks >= max_blocks) goto end;
						}
					}
				}
				++i;
			}
		}
		++tries;
		if (BUTTON_PRESS()) {
			Dbprintf("Button pressed, stopping.");
			goto end;
		}
	}
	while (found_blocks != max_blocks);

 end:
	Dbprintf("-----------------------------------------");
	Dbprintf("Memory content:");
	Dbprintf("-----------------------------------------");
	for (i = 0; i < max_blocks; ++i) {
		if (memory_blocks[i][ALLOC])
			print_result("Block", memory_blocks[i], 16);
		else
			Dbprintf("<missing block %d>", i);
	}
	Dbprintf("-----------------------------------------");
	
	if (found_blocks < max_blocks) {
		Dbprintf("-----------------------------------------");
		Dbprintf("Blocks with unknown position:");
		Dbprintf("-----------------------------------------");
		for (i = 0; i < single_blocks_cnt; ++i)
			print_result("Block", single_blocks[i], 16);
		
		Dbprintf("-----------------------------------------");
	}
	cmd_send(CMD_ACK,0,0,0,0,0);
}

static void RealWritePCF7931(uint8_t *pass, uint16_t init_delay, int32_t l, int32_t p, uint8_t address, uint8_t byte, uint8_t data) {
	uint32_t tab[1024]={0}; // data times frame
	uint32_t u = 0;
	uint8_t parity = 0;
	bool comp = 0;

	//BUILD OF THE DATA FRAME
	//alimentation of the tag (time for initializing)
	AddPatternPCF7931(init_delay, 0, 8192/2*T0_PCF, tab);
	AddPatternPCF7931(8192/2*T0_PCF + 319*T0_PCF+70, 3*T0_PCF, 29*T0_PCF, tab);
	//password indication bit
	AddBitPCF7931(1, tab, l, p);
	// password (on 56 bits)
	AddBytePCF7931(pass[0], tab, l, p);
	AddBytePCF7931(pass[1], tab, l, p);
	AddBytePCF7931(pass[2], tab, l, p);
	AddBytePCF7931(pass[3], tab, l, p);
	AddBytePCF7931(pass[4], tab, l, p);
	AddBytePCF7931(pass[5], tab, l, p);
	AddBytePCF7931(pass[6], tab, l, p);
	//programming mode (0 or 1)
	AddBitPCF7931(0, tab, l, p);
	
	//block adress on 6 bits
	for (u = 0; u < 6; ++u) {
		if (address & (1 << u)) {	// bit 1
			 ++parity;
			 AddBitPCF7931(1, tab, l, p);
		} else {					// bit 0
			 AddBitPCF7931(0, tab, l, p);
		}
	}
	
	//byte address on 4 bits
	for (u = 0; u < 4; ++u)
	{
		if (byte & (1 << u)) { 	// bit 1
			 parity++;
			 AddBitPCF7931(1, tab, l, p);
		}
		else				// bit 0
			 AddBitPCF7931(0, tab, l, p);
	}
	
	//data on 8 bits
	for (u=0; u<8; u++)
	{
		if (data&(1<<u)) {	// bit 1
			 parity++;
			 AddBitPCF7931(1, tab, l, p);
		} 
		else				//bit 0
			 AddBitPCF7931(0, tab, l, p);
	}

	//parity bit
	if ((parity % 2) == 0)
	 	AddBitPCF7931(0, tab, l, p); //even parity
	else
		AddBitPCF7931(1, tab, l, p);//odd parity

	//time access memory
	AddPatternPCF7931(5120+2680, 0, 0, tab);

	//conversion of the scale time
	for (u = 0; u < 500; ++u)
		tab[u] = (tab[u] * 3) / 2;

	//compennsation of the counter reload
	while (!comp) {
		comp = 1;
		for (u = 0; tab[u] != 0; ++u)
			if(tab[u] > 0xFFFF) {
			  tab[u] -= 0xFFFF;
			  comp = 0;
			}
	}

	SendCmdPCF7931(tab);
}

void BruteForcePCF7931(uint64_t password, uint8_t tries, uint16_t init_delay, int32_t l, int32_t p) {
	uint8_t i = 0;
	uint8_t pass_array[7];
	
	while (password < 0x00FFFFFFFFFFFFFF) {
		if (BUTTON_PRESS()) {
			Dbprintf("Button pressed, stopping bruteforce ...");
			return;
		}
		
		pass_array[0] = password & 0xFF;
		pass_array[1] = (password >> 8) & 0xFF;
		pass_array[2] = (password >> 16) & 0xFF;
		pass_array[3] = (password >> 24) & 0xFF;
		pass_array[4] = (password >> 32) & 0xFF;
		pass_array[5] = (password >> 40) & 0xFF;
		pass_array[6] = (password >> 48) & 0xFF;

		Dbprintf("Trying: %02x %02x %02x %02x %02x %02x %02x ...",
			pass_array[0],
			pass_array[1],
			pass_array[2],
			pass_array[3],
			pass_array[4],
			pass_array[5],
			pass_array[6]);
		
		for (i = 0; i < tries; ++i)
			RealWritePCF7931
			(
				pass_array,
				init_delay,
				l,
				p,
				0,
				7,
				0x01
			);
	
		++password;	
	}
}

/* Write on a byte of a PCF7931 tag
 * @param address : address of the block to write
   @param byte : address of the byte to write
    @param data : data to write
 */
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) {
	Dbprintf("Initialization delay : %d us", init_delay);
	Dbprintf("Offsets : %d us on the low pulses width, %d us on the low pulses positions", l, p);
	Dbprintf("Password (LSB first on each byte): %02x %02x %02x %02x %02x %02x %02x", pass1, pass2, pass3, pass4, pass5, pass6, pass7);
	Dbprintf("Block address : %02x", address);
	Dbprintf("Byte address : %02x", byte);
	Dbprintf("Data : %02x", data);
	
	uint8_t password[7] = {pass1, pass2, pass3, pass4, pass5, pass6, pass7};
	
	RealWritePCF7931 (password, init_delay, l, p, address, byte, data);
}


/* Send a trame to a PCF7931 tags
 * @param tab : array of the data frame
 */

void SendCmdPCF7931(uint32_t * tab) {
	uint16_t u=0;
	uint16_t tempo=0;

	Dbprintf("Sending data frame ...");

	FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
	FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
	FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_PASSTHRU );

	LED_A_ON();

	// steal this pin from the SSP and use it to control the modulation
	AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT;
	AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;

	//initialization of the timer
	AT91C_BASE_PMC->PMC_PCER |= (0x1 << 12) | (0x1 << 13) | (0x1 << 14);
	AT91C_BASE_TCB->TCB_BMR = AT91C_TCB_TC0XC0S_NONE | AT91C_TCB_TC1XC1S_TIOA0 | AT91C_TCB_TC2XC2S_NONE;
	AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS; // timer disable
	AT91C_BASE_TC0->TC_CMR = AT91C_TC_CLKS_TIMER_DIV3_CLOCK;  //clock at 48/32 MHz
	AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKEN;
	AT91C_BASE_TCB->TCB_BCR = 1;

	tempo = AT91C_BASE_TC0->TC_CV;
	for (u = 0; tab[u] !=  0; u += 3) {
		// modulate antenna
		HIGH(GPIO_SSC_DOUT);
		while(tempo !=  tab[u])
			tempo = AT91C_BASE_TC0->TC_CV;
			
		// stop modulating antenna
		LOW(GPIO_SSC_DOUT);
		while(tempo !=  tab[u+1])
			tempo = AT91C_BASE_TC0->TC_CV;

		// modulate antenna
		HIGH(GPIO_SSC_DOUT);
		while(tempo !=  tab[u+2])
			tempo = AT91C_BASE_TC0->TC_CV;
	}

	LED_A_OFF();
	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
	SpinDelay(200);

	AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS; // timer disable
	DbpString("Data frame sent (multiple sends may be needed)");
	LED(0xFFFF, 1000);
}


/* Add a byte for building the data frame of PCF7931 tags 
 * @param b : byte to add
 * @param tab : array of the data frame
 * @param l : offset on low pulse width
 * @param p : offset on low pulse positioning
 */
bool AddBytePCF7931(uint8_t byte, uint32_t * tab, int32_t l, int32_t p) {
	uint32_t u;
	for (u = 0; u < 8; ++u) {
		if (byte & (1 << u)) {	//bit is 1
			if(AddBitPCF7931(1, tab, l, p)==1)return 1;
		} else { //bit is 0
			if(AddBitPCF7931(0, tab, l, p)==1)return 1;
		}
	}

	return 0;
}

/* Add a bits for building the data frame of PCF7931 tags 
 * @param b : bit to add
 * @param tab : array of the data frame
 * @param l : offset on low pulse width
 * @param p : offset on low pulse positioning
 */
bool AddBitPCF7931(bool b, uint32_t * tab, int32_t l, int32_t p) {
	uint8_t u = 0;

	for (u = 0; tab[u] != 0; u += 3){} //we put the cursor at the last value of the array

	if (b == 1) {	//add a bit 1
		if (u == 0)	tab[u] = 34 * T0_PCF + p;
		else		tab[u] = 34 * T0_PCF + tab[u-1] + p;

		tab[u+1] = 6 * T0_PCF+tab[u] + l;
		tab[u+2] = 88 * T0_PCF+tab[u + 1] - l - p;
		return 0;
	} else { 		//add a bit 0

		if (u == 0)	tab[u] = 98 * T0_PCF + p;
		else		tab[u] = 98 * T0_PCF + tab[u-1] + p;

		tab[u + 1] = 6 * T0_PCF + tab[u] + l;
		tab[u + 2] = 24 * T0_PCF + tab[u + 1] - l - p;
		return 0;
	}
	
	return 1;
}

/* Add a custom pattern in the data frame
 * @param a : delay of the first high pulse
 * @param b : delay of the low pulse
 * @param c : delay of the last high pulse
 * @param tab : array of the data frame
 */
bool AddPatternPCF7931(uint32_t a, uint32_t b, uint32_t c, uint32_t * tab) {
	uint32_t u = 0;
	for(u = 0; tab[u] != 0; u += 3){} //we put the cursor at the last value of the array

	if (u == 0)	tab[u] = a;
	else		tab[u] = a + tab[u - 1];

	tab[u + 1] = b + tab[u];
	tab[u + 2] = c + tab[u + 1];

	return 0;
}
Commit	Line	Data
d10e08ae	1	#include "proxmark3.h"
	2	#include "apps.h"
	3	#include "lfsampling.h"
	4	#include "pcf7931.h"
b8e461ff	5	#include "util.h"
d10e08ae	6	#include "string.h"
fc52fbd4	7	#include "fpgaloader.h"
d10e08ae	8
	9	#define T0_PCF 8 //period for the pcf7931 in us
	10	#define ALLOC 16
	11
818e15b0 S	12	size_t DemodPCF7931(uint8_t **outBlocks) {
818e15b0 S	13	uint8_t bits[256] = {0x00};
d10e08ae	14	uint8_t blocks[8][16];
818e15b0	15	uint8_t *dest = BigBuf_get_addr();
d10e08ae	16
d10e08ae	17	int GraphTraceLen = BigBuf_max_traceLen();
818e15b0	18	if (GraphTraceLen > 18000)
d10e08ae	19	GraphTraceLen = 18000;
d10e08ae	20
d10e08ae	21	int i, j, lastval, bitidx, half_switch;
	22	int clock = 64;
	23	int tolerance = clock / 8;
	24	int pmc, block_done;
	25	int lc, warnings = 0;
818e15b0	26	size_t num_blocks = 0;
d10e08ae	27	int lmin=128, lmax=128;
d10e08ae	28	uint8_t dir;
3cec7061	29	//clear read buffer
29b75739	30	BigBuf_Clear_keep_EM();
d10e08ae	31
	32	LFSetupFPGAForADC(95, true);
	33	DoAcquisition_default(0, true);
	34
	35	lmin = 64;
	36	lmax = 192;
	37
	38	i = 2;
	39
	40	/* Find first local max/min */
818e15b0	41	if(dest[1] > dest[0]) {
d10e08ae	42	while(i < GraphTraceLen) {
818e15b0	43	if( !(dest[i] > dest[i-1]) && dest[i] > lmax)
d10e08ae	44	break;
	45	i++;
	46	}
	47	dir = 0;
818e15b0	48	} else {
d10e08ae	49	while(i < GraphTraceLen) {
818e15b0	50	if( !(dest[i] < dest[i-1]) && dest[i] < lmin)
d10e08ae	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
818e15b0 S	62	for (bitidx = 0; i < GraphTraceLen; i++) {
818e15b0 S	63	if ((dest[i-1] > dest[i] && dir == 1 && dest[i] > lmax) \|\| (dest[i-1] < dest[i] && dir == 0 && dest[i] < lmin)) {
d10e08ae	64	lc = i - lastval;
	65	lastval = i;
	66
	67	// Switch depending on lc length:
	68	// Tolerance is 1/8 of clock rate (arbitrary)
cf194819	69	if (ABS(lc-clock/4) < tolerance) {
d10e08ae	70	// 16T0
	71	if((i - pmc) == lc) { /* 16T0 was previous one */
	72	/* It's a PMC ! */
	73	i += (128+127+16+32+33+16)-1;
	74	lastval = i;
	75	pmc = 0;
	76	block_done = 1;
818e15b0	77	} else {
d10e08ae	78	pmc = i;
d10e08ae	79	}
cf194819	80	} else if (ABS(lc-clock/2) < tolerance) {
d10e08ae	81	// 32TO
	82	if((i - pmc) == lc) { /* 16T0 was previous one */
	83	/* It's a PMC ! */
	84	i += (128+127+16+32+33)-1;
	85	lastval = i;
	86	pmc = 0;
	87	block_done = 1;
818e15b0 S	88	} else if(half_switch == 1) {
818e15b0 S	89	bits[bitidx++] = 0;
d10e08ae	90	half_switch = 0;
	91	}
	92	else
	93	half_switch++;
cf194819	94	} else if (ABS(lc-clock) < tolerance) {
d10e08ae	95	// 64TO
818e15b0	96	bits[bitidx++] = 1;
d10e08ae	97	} else {
d10e08ae	98	// Error
818e15b0	99	if (++warnings > 10) {
d10e08ae	100	Dbprintf("Error: too many detection errors, aborting.");
	101	return 0;
	102	}
	103	}
	104
	105	if(block_done == 1) {
	106	if(bitidx == 128) {
818e15b0 S	107	for(j = 0; j < 16; ++j) {
	108	blocks[num_blocks][j] =
	109	128 * bits[j*8 + 7]+
	110	64 * bits[j*8 + 6] +
	111	32 * bits[j*8 + 5] +
	112	16 * bits[j*8 + 4] +
	113	8 * bits[j*8 + 3] +
	114	4 * bits[j*8 + 2] +
	115	2 * bits[j*8 + 1] +
	116	bits[j*8]
	117	;
d10e08ae	118	}
	119	num_blocks++;
	120	}
	121	bitidx = 0;
	122	block_done = 0;
	123	half_switch = 0;
	124	}
	125	if(i < GraphTraceLen)
818e15b0	126	dir = (dest[i-1] > dest[i]) ? 0 : 1;
d10e08ae	127	}
	128	if(bitidx==255)
	129	bitidx=0;
	130	warnings = 0;
	131	if(num_blocks == 4) break;
	132	}
818e15b0	133	memcpy(outBlocks, blocks, 16 * num_blocks);
d10e08ae	134	return num_blocks;
	135	}
	136
818e15b0 S	137	bool IsBlock0PCF7931(uint8_t *block) {
	138	// assuming all RFU bits are set to 0
	139	// if PAC is enabled password is set to 0
	140	if (block[7] == 0x01)
	141	{
	142	if (!memcmp(block, "\x00\x00\x00\x00\x00\x00\x00", 7) && !memcmp(block+9, "\x00\x00\x00\x00\x00\x00\x00", 7))
	143	return true;
	144	}
	145	else if (block[7] == 0x00)
	146	{
	147	if (!memcmp(block+9, "\x00\x00\x00\x00\x00\x00\x00", 7))
	148	return true;
	149	}
	150	return false;
d10e08ae	151	}
d10e08ae	152
818e15b0 S	153	bool IsBlock1PCF7931(uint8_t *block) {
	154	// assuming all RFU bits are set to 0
	155	if (block[10] == 0 && block[11] == 0 && block[12] == 0 && block[13] == 0)
	156	if((block[14] & 0x7f) <= 9 && block[15] <= 9)
	157	return true;
d10e08ae	158
818e15b0	159	return false;
d10e08ae	160	}
	161
	162	void ReadPCF7931() {
818e15b0 S	163	int found_blocks = 0; // successfully read blocks
	164	int max_blocks = 8; // readable blocks
	165	uint8_t memory_blocks[8][17]; // PCF content
	166
	167	uint8_t single_blocks[8][17]; // PFC blocks with unknown position
	168	int single_blocks_cnt = 0;
d10e08ae	169
818e15b0 S	170	size_t n = 0; // transmitted blocks
	171	uint8_t tmp_blocks[4][16]; // temporary read buffer
	172
	173	uint8_t found_0_1 = 0; // flag: blocks 0 and 1 were found
	174	int errors = 0; // error counter
	175	int tries = 0; // tries counter
	176
	177	memset(memory_blocks, 0, 817sizeof(uint8_t));
	178	memset(single_blocks, 0, 817sizeof(uint8_t));
	179
	180	int i = 0, j = 0;
d10e08ae	181
d10e08ae	182	do {
818e15b0 S	183	i = 0;
	184
	185	memset(tmp_blocks, 0, 416sizeof(uint8_t));
	186	n = DemodPCF7931((uint8_t**)tmp_blocks);
d10e08ae	187	if(!n)
818e15b0 S	188	++errors;
	189
	190	// exit if no block is received
	191	if (errors >= 10 && found_blocks == 0 && single_blocks_cnt == 0) {
d10e08ae	192	Dbprintf("Error, no tag or bad tag");
	193	return;
	194	}
818e15b0 S	195	// exit if too many errors during reading
818e15b0 S	196	if (tries > 50 && (2*errors > tries)) {
d10e08ae	197	Dbprintf("Error reading the tag");
	198	Dbprintf("Here is the partial content");
	199	goto end;
	200	}
818e15b0 S	201
	202	// our logic breaks if we don't get at least two blocks
	203	if (n < 2) {
	204	if (n == 0 \|\| !memcmp(tmp_blocks[0], "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", 16))
	205	continue;
	206
	207	if (single_blocks_cnt < max_blocks) {
	208	for (i = 0; i < single_blocks_cnt; ++i) {
	209	if (!memcmp(single_blocks[i], tmp_blocks[0], 16)) {
	210	j = 1;
d10e08ae	211	break;
	212	}
	213	}
818e15b0 S	214	if (j != 1) {
	215	memcpy(single_blocks[single_blocks_cnt], tmp_blocks[0], 16);
	216	single_blocks_cnt++;
	217	}
	218	j = 0;
d10e08ae	219	}
818e15b0 S	220	++tries;
	221	continue;
	222	}
	223
	224	Dbprintf("(dbg) got %d blocks (%d/%d found) (%d tries, %d errors)", n, found_blocks, (max_blocks == 0 ? found_blocks : max_blocks), tries, errors);
	225
	226	i = 0;
	227	if(!found_0_1) {
	228	while (i < n - 1) {
	229	if (IsBlock0PCF7931(tmp_blocks[i]) && IsBlock1PCF7931(tmp_blocks[i+1])) {
	230	found_0_1 = 1;
	231	memcpy(memory_blocks[0], tmp_blocks[i], 16);
	232	memcpy(memory_blocks[1], tmp_blocks[i+1], 16);
	233	memory_blocks[0][ALLOC] = memory_blocks[1][ALLOC] = 1;
	234	// block 1 tells how many blocks are going to be sent
	235	max_blocks = MAX((memory_blocks[1][14] & 0x7f), memory_blocks[1][15]) + 1;
	236	found_blocks = 2;
	237
	238	Dbprintf("Found blocks 0 and 1. PCF is transmitting %d blocks.", max_blocks);
	239
	240	// handle the following blocks
	241	for (j = i + 2; j < n; ++j) {
	242	memcpy(memory_blocks[found_blocks], tmp_blocks[j], 16);
	243	memory_blocks[found_blocks][ALLOC] = 1;
	244	++found_blocks;
	245	}
	246	break;
	247	}
	248	++i;
	249	}
	250	} else {
	251	// Trying to re-order blocks
	252	// Look for identical block in memory blocks
	253	while (i < n-1) {
	254	// skip all zeroes blocks
	255	if (memcmp(tmp_blocks[i], "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", 16)) {
	256	for (j = 1; j < max_blocks - 1; ++j) {
	257	if (!memcmp(tmp_blocks[i], memory_blocks[j], 16) && !memory_blocks[j+1][ALLOC]) {
	258	memcpy(memory_blocks[j+1], tmp_blocks[i+1], 16);
	259	memory_blocks[j+1][ALLOC] = 1;
	260	if (++found_blocks >= max_blocks) goto end;
	261	}
	262	}
	263	}
	264	if (memcmp(tmp_blocks[i+1], "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", 16)) {
	265	for (j = 0; j < max_blocks; ++j) {
	266	if (!memcmp(tmp_blocks[i+1], memory_blocks[j], 16) && !memory_blocks[(j == 0 ? max_blocks : j) -1][ALLOC]) {
	267	if (j == 0) {
	268	memcpy(memory_blocks[max_blocks - 1], tmp_blocks[i], 16);
	269	memory_blocks[max_blocks - 1][ALLOC] = 1;
	270	} else {
	271	memcpy(memory_blocks[j-1], tmp_blocks[i], 16);
	272	memory_blocks[j-1][ALLOC] = 1;
d10e08ae	273	}
818e15b0	274	if (++found_blocks >= max_blocks) goto end;
d10e08ae	275	}
	276	}
	277	}
818e15b0	278	++i;
d10e08ae	279	}
d10e08ae	280	}
818e15b0 S	281	++tries;
	282	if (BUTTON_PRESS()) {
	283	Dbprintf("Button pressed, stopping.");
	284	goto end;
	285	}
	286	}
	287	while (found_blocks != max_blocks);
	288
d10e08ae	289	end:
	290	Dbprintf("-----------------------------------------");
	291	Dbprintf("Memory content:");
	292	Dbprintf("-----------------------------------------");
818e15b0 S	293	for (i = 0; i < max_blocks; ++i) {
	294	if (memory_blocks[i][ALLOC])
	295	print_result("Block", memory_blocks[i], 16);
d10e08ae	296	else
	297	Dbprintf("<missing block %d>", i);
	298	}
	299	Dbprintf("-----------------------------------------");
818e15b0 S	300
	301	if (found_blocks < max_blocks) {
	302	Dbprintf("-----------------------------------------");
	303	Dbprintf("Blocks with unknown position:");
	304	Dbprintf("-----------------------------------------");
	305	for (i = 0; i < single_blocks_cnt; ++i)
	306	print_result("Block", single_blocks[i], 16);
	307
	308	Dbprintf("-----------------------------------------");
	309	}
7cfc777b	310	cmd_send(CMD_ACK,0,0,0,0,0);
d10e08ae	311	}
d10e08ae	312
818e15b0	313	static void RealWritePCF7931(uint8_t *pass, uint16_t init_delay, int32_t l, int32_t p, uint8_t address, uint8_t byte, uint8_t data) {
d10e08ae	314	uint32_t tab[1024]={0}; // data times frame
	315	uint32_t u = 0;
	316	uint8_t parity = 0;
	317	bool comp = 0;
	318
	319	//BUILD OF THE DATA FRAME
d10e08ae	320	//alimentation of the tag (time for initializing)
d10e08ae	321	AddPatternPCF7931(init_delay, 0, 8192/2*T0_PCF, tab);
d10e08ae	322	AddPatternPCF7931(8192/2T0_PCF + 319T0_PCF+70, 3T0_PCF, 29T0_PCF, tab);
d10e08ae	323	//password indication bit
d10e08ae	324	AddBitPCF7931(1, tab, l, p);
818e15b0 S	325	// password (on 56 bits)
	326	AddBytePCF7931(pass[0], tab, l, p);
	327	AddBytePCF7931(pass[1], tab, l, p);
	328	AddBytePCF7931(pass[2], tab, l, p);
	329	AddBytePCF7931(pass[3], tab, l, p);
	330	AddBytePCF7931(pass[4], tab, l, p);
	331	AddBytePCF7931(pass[5], tab, l, p);
	332	AddBytePCF7931(pass[6], tab, l, p);
d10e08ae	333	//programming mode (0 or 1)
d10e08ae	334	AddBitPCF7931(0, tab, l, p);
818e15b0	335
d10e08ae	336	//block adress on 6 bits
818e15b0 S	337	for (u = 0; u < 6; ++u) {
	338	if (address & (1 << u)) { // bit 1
	339	++parity;
d10e08ae	340	AddBitPCF7931(1, tab, l, p);
818e15b0	341	} else { // bit 0
d10e08ae	342	AddBitPCF7931(0, tab, l, p);
	343	}
	344	}
818e15b0	345
d10e08ae	346	//byte address on 4 bits
818e15b0	347	for (u = 0; u < 4; ++u)
d10e08ae	348	{
818e15b0	349	if (byte & (1 << u)) { // bit 1
d10e08ae	350	parity++;
d10e08ae	351	AddBitPCF7931(1, tab, l, p);
d10e08ae	352	}
818e15b0 S	353	else // bit 0
818e15b0 S	354	AddBitPCF7931(0, tab, l, p);
d10e08ae	355	}
818e15b0	356
d10e08ae	357	//data on 8 bits
d10e08ae	358	for (u=0; u<8; u++)
	359	{
	360	if (data&(1<<u)) { // bit 1
	361	parity++;
	362	AddBitPCF7931(1, tab, l, p);
818e15b0 S	363	}
818e15b0 S	364	else //bit 0
d10e08ae	365	AddBitPCF7931(0, tab, l, p);
d10e08ae	366	}
d10e08ae	367
d10e08ae	368	//parity bit
818e15b0	369	if ((parity % 2) == 0)
d10e08ae	370	AddBitPCF7931(0, tab, l, p); //even parity
818e15b0	371	else
d10e08ae	372	AddBitPCF7931(1, tab, l, p);//odd parity
d10e08ae	373
	374	//time access memory
	375	AddPatternPCF7931(5120+2680, 0, 0, tab);
	376
	377	//conversion of the scale time
818e15b0 S	378	for (u = 0; u < 500; ++u)
818e15b0 S	379	tab[u] = (tab[u] * 3) / 2;
d10e08ae	380
d10e08ae	381	//compennsation of the counter reload
818e15b0	382	while (!comp) {
d10e08ae	383	comp = 1;
818e15b0 S	384	for (u = 0; tab[u] != 0; ++u)
818e15b0 S	385	if(tab[u] > 0xFFFF) {
d10e08ae	386	tab[u] -= 0xFFFF;
	387	comp = 0;
	388	}
d10e08ae	389	}
	390
	391	SendCmdPCF7931(tab);
	392	}
	393
818e15b0 S	394	void BruteForcePCF7931(uint64_t password, uint8_t tries, uint16_t init_delay, int32_t l, int32_t p) {
	395	uint8_t i = 0;
	396	uint8_t pass_array[7];
	397
	398	while (password < 0x00FFFFFFFFFFFFFF) {
	399	if (BUTTON_PRESS()) {
	400	Dbprintf("Button pressed, stopping bruteforce ...");
	401	return;
	402	}
	403
	404	pass_array[0] = password & 0xFF;
	405	pass_array[1] = (password >> 8) & 0xFF;
	406	pass_array[2] = (password >> 16) & 0xFF;
	407	pass_array[3] = (password >> 24) & 0xFF;
	408	pass_array[4] = (password >> 32) & 0xFF;
	409	pass_array[5] = (password >> 40) & 0xFF;
	410	pass_array[6] = (password >> 48) & 0xFF;
	411
	412	Dbprintf("Trying: %02x %02x %02x %02x %02x %02x %02x ...",
	413	pass_array[0],
	414	pass_array[1],
	415	pass_array[2],
	416	pass_array[3],
	417	pass_array[4],
	418	pass_array[5],
	419	pass_array[6]);
	420
	421	for (i = 0; i < tries; ++i)
	422	RealWritePCF7931
	423	(
	424	pass_array,
	425	init_delay,
	426	l,
	427	p,
	428	0,
	429	7,
	430	0x01
	431	);
	432
	433	++password;
	434	}
	435	}
	436
	437	/* Write on a byte of a PCF7931 tag
	438	* @param address : address of the block to write
	439	@param byte : address of the byte to write
	440	@param data : data to write
	441	*/
	442	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) {
	443	Dbprintf("Initialization delay : %d us", init_delay);
	444	Dbprintf("Offsets : %d us on the low pulses width, %d us on the low pulses positions", l, p);
	445	Dbprintf("Password (LSB first on each byte): %02x %02x %02x %02x %02x %02x %02x", pass1, pass2, pass3, pass4, pass5, pass6, pass7);
	446	Dbprintf("Block address : %02x", address);
	447	Dbprintf("Byte address : %02x", byte);
	448	Dbprintf("Data : %02x", data);
	449
	450	uint8_t password[7] = {pass1, pass2, pass3, pass4, pass5, pass6, pass7};
	451
	452	RealWritePCF7931 (password, init_delay, l, p, address, byte, data);
	453	}
	454
d10e08ae	455
	456
	457	/* Send a trame to a PCF7931 tags
	458	* @param tab : array of the data frame
	459	*/
	460
818e15b0	461	void SendCmdPCF7931(uint32_t * tab) {
d10e08ae	462	uint16_t u=0;
	463	uint16_t tempo=0;
	464
818e15b0	465	Dbprintf("Sending data frame ...");
d10e08ae	466
d10e08ae	467	FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
d10e08ae	468	FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
d10e08ae	469	FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_PASSTHRU );
	470
	471	LED_A_ON();
	472
	473	// steal this pin from the SSP and use it to control the modulation
	474	AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT;
	475	AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
	476
	477	//initialization of the timer
	478	AT91C_BASE_PMC->PMC_PCER \|= (0x1 << 12) \| (0x1 << 13) \| (0x1 << 14);
	479	AT91C_BASE_TCB->TCB_BMR = AT91C_TCB_TC0XC0S_NONE \| AT91C_TCB_TC1XC1S_TIOA0 \| AT91C_TCB_TC2XC2S_NONE;
	480	AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS; // timer disable
	481	AT91C_BASE_TC0->TC_CMR = AT91C_TC_CLKS_TIMER_DIV3_CLOCK; //clock at 48/32 MHz
	482	AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKEN;
	483	AT91C_BASE_TCB->TCB_BCR = 1;
	484
d10e08ae	485	tempo = AT91C_BASE_TC0->TC_CV;
818e15b0	486	for (u = 0; tab[u] != 0; u += 3) {
d10e08ae	487	// modulate antenna
d10e08ae	488	HIGH(GPIO_SSC_DOUT);
818e15b0	489	while(tempo != tab[u])
d10e08ae	490	tempo = AT91C_BASE_TC0->TC_CV;
818e15b0	491
d10e08ae	492	// stop modulating antenna
d10e08ae	493	LOW(GPIO_SSC_DOUT);
818e15b0	494	while(tempo != tab[u+1])
d10e08ae	495	tempo = AT91C_BASE_TC0->TC_CV;
d10e08ae	496
	497	// modulate antenna
	498	HIGH(GPIO_SSC_DOUT);
818e15b0	499	while(tempo != tab[u+2])
d10e08ae	500	tempo = AT91C_BASE_TC0->TC_CV;
d10e08ae	501	}
	502
	503	LED_A_OFF();
	504	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
	505	SpinDelay(200);
	506
d10e08ae	507	AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS; // timer disable
818e15b0	508	DbpString("Data frame sent (multiple sends may be needed)");
d10e08ae	509	LED(0xFFFF, 1000);
	510	}
	511
	512
	513	/* Add a byte for building the data frame of PCF7931 tags
	514	* @param b : byte to add
	515	* @param tab : array of the data frame
	516	* @param l : offset on low pulse width
	517	* @param p : offset on low pulse positioning
	518	*/
818e15b0	519	bool AddBytePCF7931(uint8_t byte, uint32_t * tab, int32_t l, int32_t p) {
d10e08ae	520	uint32_t u;
818e15b0 S	521	for (u = 0; u < 8; ++u) {
818e15b0 S	522	if (byte & (1 << u)) { //bit is 1
d10e08ae	523	if(AddBitPCF7931(1, tab, l, p)==1)return 1;
818e15b0	524	} else { //bit is 0
d10e08ae	525	if(AddBitPCF7931(0, tab, l, p)==1)return 1;
	526	}
	527	}
	528
	529	return 0;
	530	}
	531
	532	/* Add a bits for building the data frame of PCF7931 tags
	533	* @param b : bit to add
	534	* @param tab : array of the data frame
	535	* @param l : offset on low pulse width
	536	* @param p : offset on low pulse positioning
	537	*/
818e15b0	538	bool AddBitPCF7931(bool b, uint32_t * tab, int32_t l, int32_t p) {
d10e08ae	539	uint8_t u = 0;
d10e08ae	540
818e15b0	541	for (u = 0; tab[u] != 0; u += 3){} //we put the cursor at the last value of the array
d10e08ae	542
818e15b0 S	543	if (b == 1) { //add a bit 1
	544	if (u == 0) tab[u] = 34 * T0_PCF + p;
	545	else tab[u] = 34 * T0_PCF + tab[u-1] + p;
d10e08ae	546
818e15b0 S	547	tab[u+1] = 6 * T0_PCF+tab[u] + l;
818e15b0 S	548	tab[u+2] = 88 * T0_PCF+tab[u + 1] - l - p;
d10e08ae	549	return 0;
818e15b0	550	} else { //add a bit 0
d10e08ae	551
818e15b0 S	552	if (u == 0) tab[u] = 98 * T0_PCF + p;
818e15b0 S	553	else tab[u] = 98 * T0_PCF + tab[u-1] + p;
d10e08ae	554
818e15b0 S	555	tab[u + 1] = 6 * T0_PCF + tab[u] + l;
818e15b0 S	556	tab[u + 2] = 24 * T0_PCF + tab[u + 1] - l - p;
d10e08ae	557	return 0;
d10e08ae	558	}
d10e08ae	559
	560	return 1;
	561	}
	562
	563	/* Add a custom pattern in the data frame
	564	* @param a : delay of the first high pulse
	565	* @param b : delay of the low pulse
	566	* @param c : delay of the last high pulse
	567	* @param tab : array of the data frame
	568	*/
818e15b0	569	bool AddPatternPCF7931(uint32_t a, uint32_t b, uint32_t c, uint32_t * tab) {
d10e08ae	570	uint32_t u = 0;
818e15b0	571	for(u = 0; tab[u] != 0; u += 3){} //we put the cursor at the last value of the array
d10e08ae	572
818e15b0 S	573	if (u == 0) tab[u] = a;
818e15b0 S	574	else tab[u] = a + tab[u - 1];
d10e08ae	575
818e15b0 S	576	tab[u + 1] = b + tab[u];
818e15b0 S	577	tab[u + 2] = c + tab[u + 1];
d10e08ae	578
	579	return 0;
	580	}