[proxmark3-svn] / armsrc / pcf7931.c

#include "proxmark3.h"
#include "apps.h"
#include "usb_cdc.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

	uint8_t rb1 = block[14] & 0x80;
	uint8_t rfb = block[14] & 0x7f;
	uint8_t rlb = block[15];

	if (block[10] == 0 && block[11] == 0 && block[12] == 0 && block[13] == 0)
		// block 1 is sent only if (RLB >= 1 && RFB <= 1) or RB1 enabled
		if(rfb <= rlb && rfb <= 9 && rlb <= 9 && ((rfb <= 1 && rlb >= 1) || rb1))
			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) {
			// skip if all 0s block or no blocks
			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;

			// add block to single blocks list
			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);
					print_result("got single block", single_blocks[single_blocks_cnt], 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);
		for (i = 0; i < n; ++i)
		{
			print_result("got consecutive blocks", tmp_blocks[i], 16);
		}

		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;
		}

		num_to_bytes(password, 7, pass_array);

		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"
d10e08ae	2	#include "apps.h"
867e10a5	3	#include "usb_cdc.h"
d10e08ae	4	#include "lfsampling.h"
d10e08ae	5	#include "pcf7931.h"
b8e461ff	6	#include "util.h"
d10e08ae	7	#include "string.h"
fc52fbd4	8	#include "fpgaloader.h"
d10e08ae	9
	10	#define T0_PCF 8 //period for the pcf7931 in us
	11	#define ALLOC 16
	12
818e15b0 S	13	size_t DemodPCF7931(uint8_t **outBlocks) {
818e15b0 S	14	uint8_t bits[256] = {0x00};
d10e08ae	15	uint8_t blocks[8][16];
818e15b0	16	uint8_t *dest = BigBuf_get_addr();
caaa4293	17
d10e08ae	18	int GraphTraceLen = BigBuf_max_traceLen();
818e15b0	19	if (GraphTraceLen > 18000)
d10e08ae	20	GraphTraceLen = 18000;
caaa4293	21
d10e08ae	22	int i, j, lastval, bitidx, half_switch;
	23	int clock = 64;
	24	int tolerance = clock / 8;
	25	int pmc, block_done;
	26	int lc, warnings = 0;
818e15b0	27	size_t num_blocks = 0;
d10e08ae	28	int lmin=128, lmax=128;
d10e08ae	29	uint8_t dir;
3cec7061	30	//clear read buffer
29b75739	31	BigBuf_Clear_keep_EM();
d10e08ae	32
	33	LFSetupFPGAForADC(95, true);
	34	DoAcquisition_default(0, true);
	35
	36	lmin = 64;
	37	lmax = 192;
	38
	39	i = 2;
	40
	41	/* Find first local max/min */
818e15b0	42	if(dest[1] > dest[0]) {
d10e08ae	43	while(i < GraphTraceLen) {
818e15b0	44	if( !(dest[i] > dest[i-1]) && dest[i] > lmax)
d10e08ae	45	break;
	46	i++;
	47	}
	48	dir = 0;
818e15b0	49	} else {
d10e08ae	50	while(i < GraphTraceLen) {
818e15b0	51	if( !(dest[i] < dest[i-1]) && dest[i] < lmin)
d10e08ae	52	break;
	53	i++;
	54	}
	55	dir = 1;
	56	}
	57
	58	lastval = i++;
	59	half_switch = 0;
	60	pmc = 0;
	61	block_done = 0;
	62
818e15b0 S	63	for (bitidx = 0; i < GraphTraceLen; i++) {
818e15b0 S	64	if ((dest[i-1] > dest[i] && dir == 1 && dest[i] > lmax) \|\| (dest[i-1] < dest[i] && dir == 0 && dest[i] < lmin)) {
d10e08ae	65	lc = i - lastval;
	66	lastval = i;
	67
	68	// Switch depending on lc length:
	69	// Tolerance is 1/8 of clock rate (arbitrary)
cf194819	70	if (ABS(lc-clock/4) < tolerance) {
d10e08ae	71	// 16T0
	72	if((i - pmc) == lc) { /* 16T0 was previous one */
	73	/* It's a PMC ! */
	74	i += (128+127+16+32+33+16)-1;
	75	lastval = i;
	76	pmc = 0;
	77	block_done = 1;
818e15b0	78	} else {
d10e08ae	79	pmc = i;
d10e08ae	80	}
cf194819	81	} else if (ABS(lc-clock/2) < tolerance) {
d10e08ae	82	// 32TO
	83	if((i - pmc) == lc) { /* 16T0 was previous one */
	84	/* It's a PMC ! */
	85	i += (128+127+16+32+33)-1;
	86	lastval = i;
	87	pmc = 0;
	88	block_done = 1;
818e15b0 S	89	} else if(half_switch == 1) {
818e15b0 S	90	bits[bitidx++] = 0;
d10e08ae	91	half_switch = 0;
	92	}
	93	else
	94	half_switch++;
cf194819	95	} else if (ABS(lc-clock) < tolerance) {
d10e08ae	96	// 64TO
818e15b0	97	bits[bitidx++] = 1;
d10e08ae	98	} else {
d10e08ae	99	// Error
818e15b0	100	if (++warnings > 10) {
d10e08ae	101	Dbprintf("Error: too many detection errors, aborting.");
	102	return 0;
	103	}
	104	}
	105
	106	if(block_done == 1) {
	107	if(bitidx == 128) {
818e15b0 S	108	for(j = 0; j < 16; ++j) {
	109	blocks[num_blocks][j] =
	110	128 * bits[j*8 + 7]+
caaa4293	111	64 * bits[j*8 + 6] +
818e15b0 S	112	32 * bits[j*8 + 5] +
	113	16 * bits[j*8 + 4] +
	114	8 * bits[j*8 + 3] +
	115	4 * bits[j*8 + 2] +
	116	2 * bits[j*8 + 1] +
	117	bits[j*8]
	118	;
d10e08ae	119	}
	120	num_blocks++;
	121	}
	122	bitidx = 0;
	123	block_done = 0;
	124	half_switch = 0;
	125	}
	126	if(i < GraphTraceLen)
818e15b0	127	dir = (dest[i-1] > dest[i]) ? 0 : 1;
d10e08ae	128	}
	129	if(bitidx==255)
	130	bitidx=0;
	131	warnings = 0;
	132	if(num_blocks == 4) break;
	133	}
818e15b0	134	memcpy(outBlocks, blocks, 16 * num_blocks);
d10e08ae	135	return num_blocks;
	136	}
	137
818e15b0 S	138	bool IsBlock0PCF7931(uint8_t *block) {
	139	// assuming all RFU bits are set to 0
	140	// if PAC is enabled password is set to 0
	141	if (block[7] == 0x01)
	142	{
	143	if (!memcmp(block, "\x00\x00\x00\x00\x00\x00\x00", 7) && !memcmp(block+9, "\x00\x00\x00\x00\x00\x00\x00", 7))
	144	return true;
	145	}
	146	else if (block[7] == 0x00)
	147	{
	148	if (!memcmp(block+9, "\x00\x00\x00\x00\x00\x00\x00", 7))
	149	return true;
	150	}
	151	return false;
d10e08ae	152	}
d10e08ae	153
818e15b0 S	154	bool IsBlock1PCF7931(uint8_t *block) {
818e15b0 S	155	// assuming all RFU bits are set to 0
cfa9c98d S	156
	157	uint8_t rb1 = block[14] & 0x80;
	158	uint8_t rfb = block[14] & 0x7f;
	159	uint8_t rlb = block[15];
	160
818e15b0	161	if (block[10] == 0 && block[11] == 0 && block[12] == 0 && block[13] == 0)
cfa9c98d S	162	// block 1 is sent only if (RLB >= 1 && RFB <= 1) or RB1 enabled
cfa9c98d S	163	if(rfb <= rlb && rfb <= 9 && rlb <= 9 && ((rfb <= 1 && rlb >= 1) \|\| rb1))
818e15b0	164	return true;
d10e08ae	165
818e15b0	166	return false;
d10e08ae	167	}
	168
	169	void ReadPCF7931() {
818e15b0	170	int found_blocks = 0; // successfully read blocks
caaa4293	171	int max_blocks = 8; // readable blocks
818e15b0	172	uint8_t memory_blocks[8][17]; // PCF content
caaa4293	173
818e15b0 S	174	uint8_t single_blocks[8][17]; // PFC blocks with unknown position
818e15b0 S	175	int single_blocks_cnt = 0;
d10e08ae	176
caaa4293	177	size_t n = 0; // transmitted blocks
818e15b0	178	uint8_t tmp_blocks[4][16]; // temporary read buffer
caaa4293	179
818e15b0 S	180	uint8_t found_0_1 = 0; // flag: blocks 0 and 1 were found
	181	int errors = 0; // error counter
	182	int tries = 0; // tries counter
caaa4293	183
818e15b0 S	184	memset(memory_blocks, 0, 817sizeof(uint8_t));
818e15b0 S	185	memset(single_blocks, 0, 817sizeof(uint8_t));
caaa4293	186
818e15b0	187	int i = 0, j = 0;
d10e08ae	188
d10e08ae	189	do {
818e15b0	190	i = 0;
caaa4293	191
818e15b0 S	192	memset(tmp_blocks, 0, 416sizeof(uint8_t));
818e15b0 S	193	n = DemodPCF7931((uint8_t**)tmp_blocks);
d10e08ae	194	if(!n)
818e15b0	195	++errors;
caaa4293	196
caaa4293	197	// exit if no block is received
818e15b0	198	if (errors >= 10 && found_blocks == 0 && single_blocks_cnt == 0) {
d10e08ae	199	Dbprintf("Error, no tag or bad tag");
	200	return;
	201	}
cfa9c98d	202
caaa4293	203	// exit if too many errors during reading
818e15b0	204	if (tries > 50 && (2*errors > tries)) {
d10e08ae	205	Dbprintf("Error reading the tag");
	206	Dbprintf("Here is the partial content");
	207	goto end;
	208	}
caaa4293	209
818e15b0 S	210	// our logic breaks if we don't get at least two blocks
818e15b0 S	211	if (n < 2) {
cfa9c98d	212	// skip if all 0s block or no blocks
818e15b0 S	213	if (n == 0 \|\| !memcmp(tmp_blocks[0], "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", 16))
	214	continue;
	215
cfa9c98d	216	// add block to single blocks list
818e15b0 S	217	if (single_blocks_cnt < max_blocks) {
	218	for (i = 0; i < single_blocks_cnt; ++i) {
	219	if (!memcmp(single_blocks[i], tmp_blocks[0], 16)) {
	220	j = 1;
d10e08ae	221	break;
	222	}
	223	}
818e15b0 S	224	if (j != 1) {
818e15b0 S	225	memcpy(single_blocks[single_blocks_cnt], tmp_blocks[0], 16);
cfa9c98d	226	print_result("got single block", single_blocks[single_blocks_cnt], 16);
818e15b0 S	227	single_blocks_cnt++;
	228	}
	229	j = 0;
d10e08ae	230	}
818e15b0 S	231	++tries;
818e15b0 S	232	continue;
caaa4293	233	}
	234
	235	Dbprintf("(dbg) got %d blocks (%d/%d found) (%d tries, %d errors)", n, found_blocks, (max_blocks == 0 ? found_blocks : max_blocks), tries, errors);
cfa9c98d S	236	for (i = 0; i < n; ++i)
	237	{
	238	print_result("got consecutive blocks", tmp_blocks[i], 16);
	239	}
818e15b0 S	240
818e15b0 S	241	i = 0;
caaa4293	242	if(!found_0_1) {
818e15b0 S	243	while (i < n - 1) {
	244	if (IsBlock0PCF7931(tmp_blocks[i]) && IsBlock1PCF7931(tmp_blocks[i+1])) {
	245	found_0_1 = 1;
	246	memcpy(memory_blocks[0], tmp_blocks[i], 16);
	247	memcpy(memory_blocks[1], tmp_blocks[i+1], 16);
	248	memory_blocks[0][ALLOC] = memory_blocks[1][ALLOC] = 1;
	249	// block 1 tells how many blocks are going to be sent
	250	max_blocks = MAX((memory_blocks[1][14] & 0x7f), memory_blocks[1][15]) + 1;
	251	found_blocks = 2;
caaa4293	252
818e15b0	253	Dbprintf("Found blocks 0 and 1. PCF is transmitting %d blocks.", max_blocks);
caaa4293	254
818e15b0 S	255	// handle the following blocks
	256	for (j = i + 2; j < n; ++j) {
	257	memcpy(memory_blocks[found_blocks], tmp_blocks[j], 16);
	258	memory_blocks[found_blocks][ALLOC] = 1;
	259	++found_blocks;
	260	}
	261	break;
	262	}
	263	++i;
	264	}
	265	} else {
	266	// Trying to re-order blocks
	267	// Look for identical block in memory blocks
	268	while (i < n-1) {
	269	// skip all zeroes blocks
	270	if (memcmp(tmp_blocks[i], "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", 16)) {
	271	for (j = 1; j < max_blocks - 1; ++j) {
	272	if (!memcmp(tmp_blocks[i], memory_blocks[j], 16) && !memory_blocks[j+1][ALLOC]) {
	273	memcpy(memory_blocks[j+1], tmp_blocks[i+1], 16);
	274	memory_blocks[j+1][ALLOC] = 1;
	275	if (++found_blocks >= max_blocks) goto end;
	276	}
	277	}
	278	}
	279	if (memcmp(tmp_blocks[i+1], "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", 16)) {
	280	for (j = 0; j < max_blocks; ++j) {
	281	if (!memcmp(tmp_blocks[i+1], memory_blocks[j], 16) && !memory_blocks[(j == 0 ? max_blocks : j) -1][ALLOC]) {
	282	if (j == 0) {
	283	memcpy(memory_blocks[max_blocks - 1], tmp_blocks[i], 16);
	284	memory_blocks[max_blocks - 1][ALLOC] = 1;
	285	} else {
	286	memcpy(memory_blocks[j-1], tmp_blocks[i], 16);
	287	memory_blocks[j-1][ALLOC] = 1;
d10e08ae	288	}
818e15b0	289	if (++found_blocks >= max_blocks) goto end;
d10e08ae	290	}
	291	}
	292	}
818e15b0	293	++i;
d10e08ae	294	}
d10e08ae	295	}
818e15b0 S	296	++tries;
	297	if (BUTTON_PRESS()) {
	298	Dbprintf("Button pressed, stopping.");
	299	goto end;
	300	}
	301	}
cfa9c98d	302	while (found_blocks < max_blocks);
818e15b0	303
d10e08ae	304	end:
	305	Dbprintf("-----------------------------------------");
	306	Dbprintf("Memory content:");
	307	Dbprintf("-----------------------------------------");
818e15b0 S	308	for (i = 0; i < max_blocks; ++i) {
	309	if (memory_blocks[i][ALLOC])
	310	print_result("Block", memory_blocks[i], 16);
d10e08ae	311	else
	312	Dbprintf("<missing block %d>", i);
	313	}
	314	Dbprintf("-----------------------------------------");
caaa4293	315
818e15b0 S	316	if (found_blocks < max_blocks) {
	317	Dbprintf("-----------------------------------------");
	318	Dbprintf("Blocks with unknown position:");
	319	Dbprintf("-----------------------------------------");
	320	for (i = 0; i < single_blocks_cnt; ++i)
	321	print_result("Block", single_blocks[i], 16);
caaa4293	322
818e15b0 S	323	Dbprintf("-----------------------------------------");
818e15b0 S	324	}
7cfc777b	325	cmd_send(CMD_ACK,0,0,0,0,0);
d10e08ae	326	}
d10e08ae	327
818e15b0	328	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	329	uint32_t tab[1024]={0}; // data times frame
	330	uint32_t u = 0;
	331	uint8_t parity = 0;
	332	bool comp = 0;
	333
	334	//BUILD OF THE DATA FRAME
d10e08ae	335	//alimentation of the tag (time for initializing)
d10e08ae	336	AddPatternPCF7931(init_delay, 0, 8192/2*T0_PCF, tab);
d10e08ae	337	AddPatternPCF7931(8192/2T0_PCF + 319T0_PCF+70, 3T0_PCF, 29T0_PCF, tab);
d10e08ae	338	//password indication bit
d10e08ae	339	AddBitPCF7931(1, tab, l, p);
818e15b0 S	340	// password (on 56 bits)
	341	AddBytePCF7931(pass[0], tab, l, p);
	342	AddBytePCF7931(pass[1], tab, l, p);
	343	AddBytePCF7931(pass[2], tab, l, p);
	344	AddBytePCF7931(pass[3], tab, l, p);
	345	AddBytePCF7931(pass[4], tab, l, p);
	346	AddBytePCF7931(pass[5], tab, l, p);
	347	AddBytePCF7931(pass[6], tab, l, p);
d10e08ae	348	//programming mode (0 or 1)
d10e08ae	349	AddBitPCF7931(0, tab, l, p);
caaa4293	350
d10e08ae	351	//block adress on 6 bits
818e15b0	352	for (u = 0; u < 6; ++u) {
caaa4293	353	if (address & (1 << u)) { // bit 1
818e15b0	354	++parity;
d10e08ae	355	AddBitPCF7931(1, tab, l, p);
caaa4293	356	} else { // bit 0
d10e08ae	357	AddBitPCF7931(0, tab, l, p);
	358	}
	359	}
caaa4293	360
d10e08ae	361	//byte address on 4 bits
818e15b0	362	for (u = 0; u < 4; ++u)
d10e08ae	363	{
caaa4293	364	if (byte & (1 << u)) { // bit 1
d10e08ae	365	parity++;
d10e08ae	366	AddBitPCF7931(1, tab, l, p);
d10e08ae	367	}
caaa4293	368	else // bit 0
818e15b0	369	AddBitPCF7931(0, tab, l, p);
d10e08ae	370	}
caaa4293	371
d10e08ae	372	//data on 8 bits
d10e08ae	373	for (u=0; u<8; u++)
d10e08ae	374	{
caaa4293	375	if (data&(1<<u)) { // bit 1
d10e08ae	376	parity++;
d10e08ae	377	AddBitPCF7931(1, tab, l, p);
caaa4293	378	}
caaa4293	379	else //bit 0
d10e08ae	380	AddBitPCF7931(0, tab, l, p);
d10e08ae	381	}
d10e08ae	382
d10e08ae	383	//parity bit
818e15b0	384	if ((parity % 2) == 0)
caaa4293	385	AddBitPCF7931(0, tab, l, p); //even parity
818e15b0	386	else
d10e08ae	387	AddBitPCF7931(1, tab, l, p);//odd parity
d10e08ae	388
	389	//time access memory
	390	AddPatternPCF7931(5120+2680, 0, 0, tab);
	391
	392	//conversion of the scale time
818e15b0 S	393	for (u = 0; u < 500; ++u)
818e15b0 S	394	tab[u] = (tab[u] * 3) / 2;
d10e08ae	395
d10e08ae	396	//compennsation of the counter reload
818e15b0	397	while (!comp) {
d10e08ae	398	comp = 1;
818e15b0 S	399	for (u = 0; tab[u] != 0; ++u)
818e15b0 S	400	if(tab[u] > 0xFFFF) {
d10e08ae	401	tab[u] -= 0xFFFF;
	402	comp = 0;
	403	}
d10e08ae	404	}
	405
	406	SendCmdPCF7931(tab);
	407	}
	408
818e15b0 S	409	void BruteForcePCF7931(uint64_t password, uint8_t tries, uint16_t init_delay, int32_t l, int32_t p) {
	410	uint8_t i = 0;
	411	uint8_t pass_array[7];
caaa4293	412
818e15b0 S	413	while (password < 0x00FFFFFFFFFFFFFF) {
	414	if (BUTTON_PRESS()) {
	415	Dbprintf("Button pressed, stopping bruteforce ...");
	416	return;
	417	}
caaa4293	418
caaa4293	419	num_to_bytes(password, 7, pass_array);
818e15b0 S	420
	421	Dbprintf("Trying: %02x %02x %02x %02x %02x %02x %02x ...",
	422	pass_array[0],
	423	pass_array[1],
	424	pass_array[2],
	425	pass_array[3],
	426	pass_array[4],
	427	pass_array[5],
	428	pass_array[6]);
caaa4293	429
818e15b0 S	430	for (i = 0; i < tries; ++i)
	431	RealWritePCF7931
	432	(
	433	pass_array,
	434	init_delay,
	435	l,
	436	p,
	437	0,
	438	7,
	439	0x01
	440	);
caaa4293	441
caaa4293	442	++password;
818e15b0 S	443	}
	444	}
	445
	446	/* Write on a byte of a PCF7931 tag
	447	* @param address : address of the block to write
	448	@param byte : address of the byte to write
caaa4293	449	@param data : data to write
818e15b0 S	450	*/
	451	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) {
	452	Dbprintf("Initialization delay : %d us", init_delay);
	453	Dbprintf("Offsets : %d us on the low pulses width, %d us on the low pulses positions", l, p);
	454	Dbprintf("Password (LSB first on each byte): %02x %02x %02x %02x %02x %02x %02x", pass1, pass2, pass3, pass4, pass5, pass6, pass7);
	455	Dbprintf("Block address : %02x", address);
	456	Dbprintf("Byte address : %02x", byte);
	457	Dbprintf("Data : %02x", data);
caaa4293	458
818e15b0	459	uint8_t password[7] = {pass1, pass2, pass3, pass4, pass5, pass6, pass7};
caaa4293	460
818e15b0 S	461	RealWritePCF7931 (password, init_delay, l, p, address, byte, data);
	462	}
	463
d10e08ae	464
	465
	466	/* Send a trame to a PCF7931 tags
	467	* @param tab : array of the data frame
	468	*/
	469
818e15b0	470	void SendCmdPCF7931(uint32_t * tab) {
d10e08ae	471	uint16_t u=0;
	472	uint16_t tempo=0;
	473
818e15b0	474	Dbprintf("Sending data frame ...");
d10e08ae	475
d10e08ae	476	FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
d10e08ae	477	FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
d10e08ae	478	FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_PASSTHRU );
	479
	480	LED_A_ON();
	481
	482	// steal this pin from the SSP and use it to control the modulation
	483	AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT;
	484	AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
	485
	486	//initialization of the timer
	487	AT91C_BASE_PMC->PMC_PCER \|= (0x1 << 12) \| (0x1 << 13) \| (0x1 << 14);
	488	AT91C_BASE_TCB->TCB_BMR = AT91C_TCB_TC0XC0S_NONE \| AT91C_TCB_TC1XC1S_TIOA0 \| AT91C_TCB_TC2XC2S_NONE;
	489	AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS; // timer disable
	490	AT91C_BASE_TC0->TC_CMR = AT91C_TC_CLKS_TIMER_DIV3_CLOCK; //clock at 48/32 MHz
	491	AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKEN;
	492	AT91C_BASE_TCB->TCB_BCR = 1;
	493
d10e08ae	494	tempo = AT91C_BASE_TC0->TC_CV;
818e15b0	495	for (u = 0; tab[u] != 0; u += 3) {
d10e08ae	496	// modulate antenna
d10e08ae	497	HIGH(GPIO_SSC_DOUT);
818e15b0	498	while(tempo != tab[u])
d10e08ae	499	tempo = AT91C_BASE_TC0->TC_CV;
caaa4293	500
d10e08ae	501	// stop modulating antenna
d10e08ae	502	LOW(GPIO_SSC_DOUT);
818e15b0	503	while(tempo != tab[u+1])
d10e08ae	504	tempo = AT91C_BASE_TC0->TC_CV;
d10e08ae	505
	506	// modulate antenna
	507	HIGH(GPIO_SSC_DOUT);
818e15b0	508	while(tempo != tab[u+2])
d10e08ae	509	tempo = AT91C_BASE_TC0->TC_CV;
d10e08ae	510	}
	511
	512	LED_A_OFF();
	513	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
	514	SpinDelay(200);
	515
d10e08ae	516	AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS; // timer disable
818e15b0	517	DbpString("Data frame sent (multiple sends may be needed)");
d10e08ae	518	LED(0xFFFF, 1000);
	519	}
	520
	521
caaa4293	522	/* Add a byte for building the data frame of PCF7931 tags
d10e08ae	523	* @param b : byte to add
	524	* @param tab : array of the data frame
	525	* @param l : offset on low pulse width
	526	* @param p : offset on low pulse positioning
	527	*/
818e15b0	528	bool AddBytePCF7931(uint8_t byte, uint32_t * tab, int32_t l, int32_t p) {
d10e08ae	529	uint32_t u;
818e15b0	530	for (u = 0; u < 8; ++u) {
caaa4293	531	if (byte & (1 << u)) { //bit is 1
d10e08ae	532	if(AddBitPCF7931(1, tab, l, p)==1)return 1;
818e15b0	533	} else { //bit is 0
d10e08ae	534	if(AddBitPCF7931(0, tab, l, p)==1)return 1;
	535	}
	536	}
	537
	538	return 0;
	539	}
	540
caaa4293	541	/* Add a bits for building the data frame of PCF7931 tags
d10e08ae	542	* @param b : bit to add
	543	* @param tab : array of the data frame
	544	* @param l : offset on low pulse width
	545	* @param p : offset on low pulse positioning
	546	*/
818e15b0	547	bool AddBitPCF7931(bool b, uint32_t * tab, int32_t l, int32_t p) {
d10e08ae	548	uint8_t u = 0;
d10e08ae	549
818e15b0	550	for (u = 0; tab[u] != 0; u += 3){} //we put the cursor at the last value of the array
d10e08ae	551
caaa4293	552	if (b == 1) { //add a bit 1
	553	if (u == 0) tab[u] = 34 * T0_PCF + p;
	554	else tab[u] = 34 * T0_PCF + tab[u-1] + p;
d10e08ae	555
818e15b0 S	556	tab[u+1] = 6 * T0_PCF+tab[u] + l;
818e15b0 S	557	tab[u+2] = 88 * T0_PCF+tab[u + 1] - l - p;
d10e08ae	558	return 0;
caaa4293	559	} else { //add a bit 0
d10e08ae	560
caaa4293	561	if (u == 0) tab[u] = 98 * T0_PCF + p;
caaa4293	562	else tab[u] = 98 * T0_PCF + tab[u-1] + p;
d10e08ae	563
818e15b0 S	564	tab[u + 1] = 6 * T0_PCF + tab[u] + l;
818e15b0 S	565	tab[u + 2] = 24 * T0_PCF + tab[u + 1] - l - p;
d10e08ae	566	return 0;
d10e08ae	567	}
caaa4293	568
d10e08ae	569	return 1;
	570	}
	571
	572	/* Add a custom pattern in the data frame
	573	* @param a : delay of the first high pulse
	574	* @param b : delay of the low pulse
	575	* @param c : delay of the last high pulse
	576	* @param tab : array of the data frame
	577	*/
818e15b0	578	bool AddPatternPCF7931(uint32_t a, uint32_t b, uint32_t c, uint32_t * tab) {
d10e08ae	579	uint32_t u = 0;
818e15b0	580	for(u = 0; tab[u] != 0; u += 3){} //we put the cursor at the last value of the array
d10e08ae	581
caaa4293	582	if (u == 0) tab[u] = a;
caaa4293	583	else tab[u] = a + tab[u - 1];
d10e08ae	584
818e15b0 S	585	tab[u + 1] = b + tab[u];
818e15b0 S	586	tab[u + 2] = c + tab[u + 1];
d10e08ae	587
	588	return 0;
	589	}