proxmark3/armsrc/Standalone/lf_em4100emul.c
2021-01-28 11:49:25 +01:00

107 lines
2.9 KiB
C

//-----------------------------------------------------------------------------
// Artyom Gnatyuk, 2020
//
// This code is licensed to you under the terms of the GNU GPL, version 2 or,
// at your option, any later version. See the LICENSE.txt file for the text of
// the license.
//-----------------------------------------------------------------------------
// LF emul - Very simple mode. Simulate only predefined in low[] IDs
// Short click - select next slot and start simulation
//-----------------------------------------------------------------------------
#include "standalone.h"
#include "proxmark3_arm.h"
#include "appmain.h"
#include "fpgaloader.h"
#include "lfops.h"
#include "util.h"
#include "dbprint.h"
#include "ticks.h"
#include "string.h"
#include "BigBuf.h"
#include "commonutil.h"
#define MAX_IND 16 // 4 LEDs - 2^4 combinations
#define LF_CLOCK 64 // for 125kHz
// low & high - array for storage IDs. Its length must be equal.
// Predefined IDs must be stored in low[].
static uint64_t low[] = {0x565A1140BE, 0x365A398149, 0x5555555555, 0xFFFFFFFFFF};
static uint8_t slots_count;
static int buflen;
void ModInfo(void) {
DbpString(" LF EM4100 simulator standalone mode");
}
static uint64_t rev_quads(uint64_t bits) {
uint64_t result = 0;
for (int i = 0; i < 16; i++) {
result += ((bits >> (60 - 4 * i)) & 0xf) << (4 * i);
}
return result >> 24;
}
static void fill_buff(uint8_t bit) {
uint8_t *bba = BigBuf_get_addr();
memset(bba + buflen, bit, LF_CLOCK / 2);
buflen += (LF_CLOCK / 2);
memset(bba + buflen, bit ^ 1, LF_CLOCK / 2);
buflen += (LF_CLOCK / 2);
}
static void construct_EM410x_emul(uint64_t id) {
int i, j;
int binary[4] = {0,0,0,0};
int parity[4] = {0,0,0,0};
buflen = 0;
for (i = 0; i < 9; i++)
fill_buff(1);
for (i = 0; i < 10; i++) {
for (j = 3; j >= 0; j--, id /= 2)
binary[j] = id % 2;
for (j = 0; j < 4; j++)
fill_buff(binary[j]);
fill_buff(binary[0] ^ binary[1] ^ binary[2] ^ binary[3]);
for (j = 0; j < 4; j++)
parity[j] ^= binary[j];
}
for (j = 0; j < 4; j++)
fill_buff(parity[j]);
fill_buff(0);
}
static void LED_Slot(int i) {
LEDsoff();
if (slots_count > 4) {
LED(i % MAX_IND, 0); //binary indication for slots_count > 4
} else {
LED(1 << i, 0); //simple indication for slots_count <=4
}
}
void RunMod(void) {
StandAloneMode();
FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
Dbprintf("[=] >> LF EM4100 simulator started <<");
int selected = 0; //selected slot after start
slots_count = ARRAYLEN(low);
for (;;) {
WDT_HIT();
if (data_available()) break;
SpinDelay(100);
SpinUp(100);
LED_Slot(selected);
construct_EM410x_emul(rev_quads(low[selected]));
SimulateTagLowFrequency(buflen, 0, true);
selected = (selected + 1) % slots_count;
}
}