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c186d2b0cc
unleashed-firmware/lib/nfc/protocols/nfcv.c
g3gg0.de c186d2b0cc
added ISO15693 (NfcV) reading, saving, emulating and revealing from privacy mode (unlock) (#2316) 
* added support for ISO15693 (NfcV) emulation, added support for reading SLIX tags
* SLIX: fixed crash situation when an invalid password was requested
* ISO15693: show emulate menu when opening file
* rename NfcV emulate scene to match other NfcV names
* optimize allocation size for signals
* ISO15693: further optimizations of allocation and free code
* ISO15693: reduce latency on state machine reset
* respond with block security status when option flag is set
* increased maximum memory size to match standard
  added security status handling/load/save
  added SELECT/QUIET handling
  more fine grained allocation routines and checks
  fix memset sizes
* added "Listen NfcV Reader" to sniff traffic from reader to card
* added correct description to delete menu
* also added DSFID/AFI handling and locking
* increase sniff log size
* scale NfcV frequency a bit, add echo mode, fix signal level at the end
* use symbolic modulated/unmodulated GPIO levels
* honor AFI field, decrease verbosity and removed debug code
* refactor defines for less namespace pollution by using NFCV_ prefixes
* correct an oversight that original cards return an generic error when addressing outside block range
* use inverse modulation, increasing readable range significantly
* rework and better document nfc chip initialization
* nfcv code review fixes
* Disable accidentally left on signal debug gpio output
* Improve NFCV Read/Info GUIs. Authored by @xMasterX, committed by @nvx
* Fix crash that occurs when you exit from NFCV emulation and start it again. Authored by @xMasterX, committed by @nvx
* Remove delay from emulation loop. This improves compatibility when the reader is Android.
* Lib: digital signal debug output pin info

Co-authored-by: Tiernan Messmer <tiernan.messmer@gmail.com>
Co-authored-by: MX <10697207+xMasterX@users.noreply.github.com>
Co-authored-by: gornekich <n.gorbadey@gmail.com>
Co-authored-by: あく <alleteam@gmail.com>
2023-06-08 14:30:53 +09:00

1399 lines
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#include <limits.h>
#include <furi.h>
#include <furi_hal.h>
#include <furi_hal_nfc.h>
#include <furi_hal_spi.h>
#include <furi_hal_gpio.h>
#include <furi_hal_cortex.h>
#include <furi_hal_resources.h>
#include <st25r3916.h>
#include <st25r3916_irq.h>
#include "nfcv.h"
#include "nfc_util.h"
#include "slix.h"
#define TAG "NfcV"
/* macros to map "modulate field" flag to GPIO level */
#define GPIO_LEVEL_MODULATED NFCV_LOAD_MODULATION_POLARITY
#define GPIO_LEVEL_UNMODULATED (!GPIO_LEVEL_MODULATED)
/* timing macros */
#define DIGITAL_SIGNAL_UNIT_S (100000000000.0f)
#define DIGITAL_SIGNAL_UNIT_US (100000.0f)
ReturnCode nfcv_inventory(uint8_t* uid) {
uint16_t received = 0;
rfalNfcvInventoryRes res;
ReturnCode ret = ERR_NONE;
for(int tries = 0; tries < NFCV_COMMAND_RETRIES; tries++) {
/* TODO: needs proper abstraction via fury_hal(_ll)_* */
ret = rfalNfcvPollerInventory(RFAL_NFCV_NUM_SLOTS_1, 0, NULL, &res, &received);
if(ret == ERR_NONE) {
break;
}
}
if(ret == ERR_NONE) {
if(uid != NULL) {
memcpy(uid, res.UID, NFCV_UID_LENGTH);
}
}
return ret;
}
ReturnCode nfcv_read_blocks(NfcVReader* reader, NfcVData* nfcv_data) {
UNUSED(reader);
uint16_t received = 0;
for(size_t block = 0; block < nfcv_data->block_num; block++) {
uint8_t rxBuf[32];
FURI_LOG_D(TAG, "Reading block %d/%d", block, (nfcv_data->block_num - 1));
ReturnCode ret = ERR_NONE;
for(int tries = 0; tries < NFCV_COMMAND_RETRIES; tries++) {
ret = rfalNfcvPollerReadSingleBlock(
RFAL_NFCV_REQ_FLAG_DEFAULT, NULL, block, rxBuf, sizeof(rxBuf), &received);
if(ret == ERR_NONE) {
break;
}
}
if(ret != ERR_NONE) {
FURI_LOG_D(TAG, "failed to read: %d", ret);
return ret;
}
memcpy(
&(nfcv_data->data[block * nfcv_data->block_size]), &rxBuf[1], nfcv_data->block_size);
FURI_LOG_D(
TAG,
" %02X %02X %02X %02X",
nfcv_data->data[block * nfcv_data->block_size + 0],
nfcv_data->data[block * nfcv_data->block_size + 1],
nfcv_data->data[block * nfcv_data->block_size + 2],
nfcv_data->data[block * nfcv_data->block_size + 3]);
}
return ERR_NONE;
}
ReturnCode nfcv_read_sysinfo(FuriHalNfcDevData* nfc_data, NfcVData* nfcv_data) {
uint8_t rxBuf[32];
uint16_t received = 0;
ReturnCode ret = ERR_NONE;
FURI_LOG_D(TAG, "Read SYSTEM INFORMATION...");
for(int tries = 0; tries < NFCV_COMMAND_RETRIES; tries++) {
/* TODO: needs proper abstraction via fury_hal(_ll)_* */
ret = rfalNfcvPollerGetSystemInformation(
RFAL_NFCV_REQ_FLAG_DEFAULT, NULL, rxBuf, sizeof(rxBuf), &received);
if(ret == ERR_NONE) {
break;
}
}
if(ret == ERR_NONE) {
nfc_data->type = FuriHalNfcTypeV;
nfc_data->uid_len = NFCV_UID_LENGTH;
/* UID is stored reversed in this response */
for(int pos = 0; pos < nfc_data->uid_len; pos++) {
nfc_data->uid[pos] = rxBuf[2 + (NFCV_UID_LENGTH - 1 - pos)];
}
nfcv_data->dsfid = rxBuf[NFCV_UID_LENGTH + 2];
nfcv_data->afi = rxBuf[NFCV_UID_LENGTH + 3];
nfcv_data->block_num = rxBuf[NFCV_UID_LENGTH + 4] + 1;
nfcv_data->block_size = rxBuf[NFCV_UID_LENGTH + 5] + 1;
nfcv_data->ic_ref = rxBuf[NFCV_UID_LENGTH + 6];
FURI_LOG_D(
TAG,
" UID: %02X %02X %02X %02X %02X %02X %02X %02X",
nfc_data->uid[0],
nfc_data->uid[1],
nfc_data->uid[2],
nfc_data->uid[3],
nfc_data->uid[4],
nfc_data->uid[5],
nfc_data->uid[6],
nfc_data->uid[7]);
FURI_LOG_D(
TAG,
" DSFID %d, AFI %d, Blocks %d, Size %d, IC Ref %d",
nfcv_data->dsfid,
nfcv_data->afi,
nfcv_data->block_num,
nfcv_data->block_size,
nfcv_data->ic_ref);
return ret;
}
FURI_LOG_D(TAG, "Failed: %d", ret);
return ret;
}
bool nfcv_read_card(NfcVReader* reader, FuriHalNfcDevData* nfc_data, NfcVData* nfcv_data) {
furi_assert(reader);
furi_assert(nfc_data);
furi_assert(nfcv_data);
if(nfcv_read_sysinfo(nfc_data, nfcv_data) != ERR_NONE) {
return false;
}
if(nfcv_read_blocks(reader, nfcv_data) != ERR_NONE) {
return false;
}
if(slix_check_card_type(nfc_data)) {
FURI_LOG_I(TAG, "NXP SLIX detected");
nfcv_data->sub_type = NfcVTypeSlix;
} else if(slix2_check_card_type(nfc_data)) {
FURI_LOG_I(TAG, "NXP SLIX2 detected");
nfcv_data->sub_type = NfcVTypeSlix2;
} else if(slix_s_check_card_type(nfc_data)) {
FURI_LOG_I(TAG, "NXP SLIX-S detected");
nfcv_data->sub_type = NfcVTypeSlixS;
} else if(slix_l_check_card_type(nfc_data)) {
FURI_LOG_I(TAG, "NXP SLIX-L detected");
nfcv_data->sub_type = NfcVTypeSlixL;
} else {
nfcv_data->sub_type = NfcVTypePlain;
}
return true;
}
void nfcv_crc(uint8_t* data, uint32_t length) {
uint32_t reg = 0xFFFF;
for(size_t i = 0; i < length; i++) {
reg = reg ^ ((uint32_t)data[i]);
for(size_t j = 0; j < 8; j++) {
if(reg & 0x0001) {
reg = (reg >> 1) ^ 0x8408;
} else {
reg = (reg >> 1);
}
}
}
uint16_t crc = ~(uint16_t)(reg & 0xffff);
data[length + 0] = crc & 0xFF;
data[length + 1] = crc >> 8;
}
void nfcv_emu_free_signals(NfcVEmuAirSignals* signals) {
furi_assert(signals);
if(signals->nfcv_resp_one) {
digital_signal_free(signals->nfcv_resp_one);
}
if(signals->nfcv_resp_zero) {
digital_signal_free(signals->nfcv_resp_zero);
}
if(signals->nfcv_resp_sof) {
digital_signal_free(signals->nfcv_resp_sof);
}
if(signals->nfcv_resp_eof) {
digital_signal_free(signals->nfcv_resp_eof);
}
signals->nfcv_resp_one = NULL;
signals->nfcv_resp_zero = NULL;
signals->nfcv_resp_sof = NULL;
signals->nfcv_resp_eof = NULL;
}
bool nfcv_emu_alloc_signals(NfcVEmuAir* air, NfcVEmuAirSignals* signals, uint32_t slowdown) {
furi_assert(air);
furi_assert(signals);
bool success = true;
if(!signals->nfcv_resp_one) {
/* logical one: unmodulated then 8 pulses */
signals->nfcv_resp_one = digital_signal_alloc(
slowdown * (air->nfcv_resp_unmod->edge_cnt + 8 * air->nfcv_resp_pulse->edge_cnt));
if(!signals->nfcv_resp_one) {
return false;
}
for(size_t i = 0; i < slowdown; i++) {
success &= digital_signal_append(signals->nfcv_resp_one, air->nfcv_resp_unmod);
}
for(size_t i = 0; i < slowdown * 8; i++) {
success &= digital_signal_append(signals->nfcv_resp_one, air->nfcv_resp_pulse);
}
if(!success) {
return false;
}
}
if(!signals->nfcv_resp_zero) {
/* logical zero: 8 pulses then unmodulated */
signals->nfcv_resp_zero = digital_signal_alloc(
slowdown * (8 * air->nfcv_resp_pulse->edge_cnt + air->nfcv_resp_unmod->edge_cnt));
if(!signals->nfcv_resp_zero) {
return false;
}
for(size_t i = 0; i < slowdown * 8; i++) {
success &= digital_signal_append(signals->nfcv_resp_zero, air->nfcv_resp_pulse);
}
for(size_t i = 0; i < slowdown; i++) {
success &= digital_signal_append(signals->nfcv_resp_zero, air->nfcv_resp_unmod);
}
if(!success) {
return false;
}
}
if(!signals->nfcv_resp_sof) {
/* SOF: unmodulated, 24 pulses, logic 1 */
signals->nfcv_resp_sof = digital_signal_alloc(
slowdown * (3 * air->nfcv_resp_unmod->edge_cnt + 24 * air->nfcv_resp_pulse->edge_cnt) +
signals->nfcv_resp_one->edge_cnt);
if(!signals->nfcv_resp_sof) {
return false;
}
for(size_t i = 0; i < slowdown * 3; i++) {
success &= digital_signal_append(signals->nfcv_resp_sof, air->nfcv_resp_unmod);
}
for(size_t i = 0; i < slowdown * 24; i++) {
success &= digital_signal_append(signals->nfcv_resp_sof, air->nfcv_resp_pulse);
}
success &= digital_signal_append(signals->nfcv_resp_sof, signals->nfcv_resp_one);
if(!success) {
return false;
}
}
if(!signals->nfcv_resp_eof) {
/* EOF: logic 0, 24 pulses, unmodulated */
signals->nfcv_resp_eof = digital_signal_alloc(
signals->nfcv_resp_zero->edge_cnt +
slowdown * (24 * air->nfcv_resp_pulse->edge_cnt + 3 * air->nfcv_resp_unmod->edge_cnt) +
air->nfcv_resp_unmod->edge_cnt);
if(!signals->nfcv_resp_eof) {
return false;
}
success &= digital_signal_append(signals->nfcv_resp_eof, signals->nfcv_resp_zero);
for(size_t i = 0; i < slowdown * 23; i++) {
success &= digital_signal_append(signals->nfcv_resp_eof, air->nfcv_resp_pulse);
}
/* we don't want to add the last level as we just want a transition to "unmodulated" again */
for(size_t i = 0; i < slowdown; i++) {
success &= digital_signal_append(signals->nfcv_resp_eof, air->nfcv_resp_half_pulse);
}
}
return success;
}
bool nfcv_emu_alloc(NfcVData* nfcv_data) {
furi_assert(nfcv_data);
if(!nfcv_data->frame) {
nfcv_data->frame = malloc(NFCV_FRAMESIZE_MAX);
if(!nfcv_data->frame) {
return false;
}
}
if(!nfcv_data->emu_air.nfcv_signal) {
/* assuming max frame length is 255 bytes */
nfcv_data->emu_air.nfcv_signal = digital_sequence_alloc(8 * 255 + 2, &gpio_spi_r_mosi);
if(!nfcv_data->emu_air.nfcv_signal) {
return false;
}
}
if(!nfcv_data->emu_air.nfcv_resp_unmod) {
/* unmodulated 256/fc or 1024/fc signal as building block */
nfcv_data->emu_air.nfcv_resp_unmod = digital_signal_alloc(4);
if(!nfcv_data->emu_air.nfcv_resp_unmod) {
return false;
}
nfcv_data->emu_air.nfcv_resp_unmod->start_level = GPIO_LEVEL_UNMODULATED;
nfcv_data->emu_air.nfcv_resp_unmod->edge_timings[0] =
(uint32_t)(NFCV_RESP_SUBC1_UNMOD_256 * DIGITAL_SIGNAL_UNIT_S);
nfcv_data->emu_air.nfcv_resp_unmod->edge_cnt = 1;
}
if(!nfcv_data->emu_air.nfcv_resp_pulse) {
/* modulated fc/32 or fc/8 pulse as building block */
nfcv_data->emu_air.nfcv_resp_pulse = digital_signal_alloc(4);
if(!nfcv_data->emu_air.nfcv_resp_pulse) {
return false;
}
nfcv_data->emu_air.nfcv_resp_pulse->start_level = GPIO_LEVEL_MODULATED;
nfcv_data->emu_air.nfcv_resp_pulse->edge_timings[0] =
(uint32_t)(NFCV_RESP_SUBC1_PULSE_32 * DIGITAL_SIGNAL_UNIT_S);
nfcv_data->emu_air.nfcv_resp_pulse->edge_timings[1] =
(uint32_t)(NFCV_RESP_SUBC1_PULSE_32 * DIGITAL_SIGNAL_UNIT_S);
nfcv_data->emu_air.nfcv_resp_pulse->edge_cnt = 2;
}
if(!nfcv_data->emu_air.nfcv_resp_half_pulse) {
/* modulated fc/32 or fc/8 pulse as building block */
nfcv_data->emu_air.nfcv_resp_half_pulse = digital_signal_alloc(4);
if(!nfcv_data->emu_air.nfcv_resp_half_pulse) {
return false;
}
nfcv_data->emu_air.nfcv_resp_half_pulse->start_level = GPIO_LEVEL_MODULATED;
nfcv_data->emu_air.nfcv_resp_half_pulse->edge_timings[0] =
(uint32_t)(NFCV_RESP_SUBC1_PULSE_32 * DIGITAL_SIGNAL_UNIT_S);
nfcv_data->emu_air.nfcv_resp_half_pulse->edge_cnt = 1;
}
bool success = true;
success &= nfcv_emu_alloc_signals(&nfcv_data->emu_air, &nfcv_data->emu_air.signals_high, 1);
success &= nfcv_emu_alloc_signals(&nfcv_data->emu_air, &nfcv_data->emu_air.signals_low, 4);
if(!success) {
FURI_LOG_E(TAG, "Failed to allocate signals");
return false;
}
digital_sequence_set_signal(
nfcv_data->emu_air.nfcv_signal,
NFCV_SIG_SOF,
nfcv_data->emu_air.signals_high.nfcv_resp_sof);
digital_sequence_set_signal(
nfcv_data->emu_air.nfcv_signal,
NFCV_SIG_BIT0,
nfcv_data->emu_air.signals_high.nfcv_resp_zero);
digital_sequence_set_signal(
nfcv_data->emu_air.nfcv_signal,
NFCV_SIG_BIT1,
nfcv_data->emu_air.signals_high.nfcv_resp_one);
digital_sequence_set_signal(
nfcv_data->emu_air.nfcv_signal,
NFCV_SIG_EOF,
nfcv_data->emu_air.signals_high.nfcv_resp_eof);
digital_sequence_set_signal(
nfcv_data->emu_air.nfcv_signal,
NFCV_SIG_LOW_SOF,
nfcv_data->emu_air.signals_low.nfcv_resp_sof);
digital_sequence_set_signal(
nfcv_data->emu_air.nfcv_signal,
NFCV_SIG_LOW_BIT0,
nfcv_data->emu_air.signals_low.nfcv_resp_zero);
digital_sequence_set_signal(
nfcv_data->emu_air.nfcv_signal,
NFCV_SIG_LOW_BIT1,
nfcv_data->emu_air.signals_low.nfcv_resp_one);
digital_sequence_set_signal(
nfcv_data->emu_air.nfcv_signal,
NFCV_SIG_LOW_EOF,
nfcv_data->emu_air.signals_low.nfcv_resp_eof);
return true;
}
void nfcv_emu_free(NfcVData* nfcv_data) {
furi_assert(nfcv_data);
if(nfcv_data->frame) {
free(nfcv_data->frame);
}
if(nfcv_data->emu_protocol_ctx) {
free(nfcv_data->emu_protocol_ctx);
}
if(nfcv_data->emu_air.nfcv_resp_unmod) {
digital_signal_free(nfcv_data->emu_air.nfcv_resp_unmod);
}
if(nfcv_data->emu_air.nfcv_resp_pulse) {
digital_signal_free(nfcv_data->emu_air.nfcv_resp_pulse);
}
if(nfcv_data->emu_air.nfcv_resp_half_pulse) {
digital_signal_free(nfcv_data->emu_air.nfcv_resp_half_pulse);
}
if(nfcv_data->emu_air.nfcv_signal) {
digital_sequence_free(nfcv_data->emu_air.nfcv_signal);
}
if(nfcv_data->emu_air.reader_signal) {
// Stop pulse reader and disable bus before free
pulse_reader_stop(nfcv_data->emu_air.reader_signal);
// Free pulse reader
pulse_reader_free(nfcv_data->emu_air.reader_signal);
}
nfcv_data->frame = NULL;
nfcv_data->emu_air.nfcv_resp_unmod = NULL;
nfcv_data->emu_air.nfcv_resp_pulse = NULL;
nfcv_data->emu_air.nfcv_resp_half_pulse = NULL;
nfcv_data->emu_air.nfcv_signal = NULL;
nfcv_data->emu_air.reader_signal = NULL;
nfcv_emu_free_signals(&nfcv_data->emu_air.signals_high);
nfcv_emu_free_signals(&nfcv_data->emu_air.signals_low);
}
void nfcv_emu_send(
FuriHalNfcTxRxContext* tx_rx,
NfcVData* nfcv,
uint8_t* data,
uint8_t length,
NfcVSendFlags flags,
uint32_t send_time) {
furi_assert(tx_rx);
furi_assert(nfcv);
/* picked default value (0) to match the most common format */
if(!flags) {
flags = NfcVSendFlagsSof | NfcVSendFlagsCrc | NfcVSendFlagsEof |
NfcVSendFlagsOneSubcarrier | NfcVSendFlagsHighRate;
}
if(flags & NfcVSendFlagsCrc) {
nfcv_crc(data, length);
length += 2;
}
/* depending on the request flags, send with high or low rate */
uint32_t bit0 = (flags & NfcVSendFlagsHighRate) ? NFCV_SIG_BIT0 : NFCV_SIG_LOW_BIT0;
uint32_t bit1 = (flags & NfcVSendFlagsHighRate) ? NFCV_SIG_BIT1 : NFCV_SIG_LOW_BIT1;
uint32_t sof = (flags & NfcVSendFlagsHighRate) ? NFCV_SIG_SOF : NFCV_SIG_LOW_SOF;
uint32_t eof = (flags & NfcVSendFlagsHighRate) ? NFCV_SIG_EOF : NFCV_SIG_LOW_EOF;
digital_sequence_clear(nfcv->emu_air.nfcv_signal);
if(flags & NfcVSendFlagsSof) {
digital_sequence_add(nfcv->emu_air.nfcv_signal, sof);
}
for(int bit_total = 0; bit_total < length * 8; bit_total++) {
uint32_t byte_pos = bit_total / 8;
uint32_t bit_pos = bit_total % 8;
uint8_t bit_val = 0x01 << bit_pos;
digital_sequence_add(nfcv->emu_air.nfcv_signal, (data[byte_pos] & bit_val) ? bit1 : bit0);
}
if(flags & NfcVSendFlagsEof) {
digital_sequence_add(nfcv->emu_air.nfcv_signal, eof);
}
furi_hal_gpio_write(&gpio_spi_r_mosi, GPIO_LEVEL_UNMODULATED);
digital_sequence_set_sendtime(nfcv->emu_air.nfcv_signal, send_time);
digital_sequence_send(nfcv->emu_air.nfcv_signal);
furi_hal_gpio_write(&gpio_spi_r_mosi, GPIO_LEVEL_UNMODULATED);
if(tx_rx->sniff_tx) {
tx_rx->sniff_tx(data, length * 8, false, tx_rx->sniff_context);
}
}
static void nfcv_revuidcpy(uint8_t* dst, uint8_t* src) {
for(int pos = 0; pos < NFCV_UID_LENGTH; pos++) {
dst[pos] = src[NFCV_UID_LENGTH - 1 - pos];
}
}
static int nfcv_revuidcmp(uint8_t* dst, uint8_t* src) {
for(int pos = 0; pos < NFCV_UID_LENGTH; pos++) {
if(dst[pos] != src[NFCV_UID_LENGTH - 1 - pos]) {
return 1;
}
}
return 0;
}
void nfcv_emu_handle_packet(
FuriHalNfcTxRxContext* tx_rx,
FuriHalNfcDevData* nfc_data,
void* nfcv_data_in) {
furi_assert(tx_rx);
furi_assert(nfc_data);
furi_assert(nfcv_data_in);
NfcVData* nfcv_data = (NfcVData*)nfcv_data_in;
NfcVEmuProtocolCtx* ctx = nfcv_data->emu_protocol_ctx;
if(nfcv_data->frame_length < 2) {
return;
}
if(nfcv_data->echo_mode) {
nfcv_emu_send(
tx_rx,
nfcv_data,
nfcv_data->frame,
nfcv_data->frame_length,
NfcVSendFlagsSof | NfcVSendFlagsHighRate | NfcVSendFlagsEof,
ctx->send_time);
snprintf(nfcv_data->last_command, sizeof(nfcv_data->last_command), "ECHO data");
return;
}
/* parse the frame data for the upcoming part 3 handling */
ctx->flags = nfcv_data->frame[0];
ctx->command = nfcv_data->frame[1];
ctx->selected = !(ctx->flags & NFCV_REQ_FLAG_INVENTORY) && (ctx->flags & NFCV_REQ_FLAG_SELECT);
ctx->addressed = !(ctx->flags & NFCV_REQ_FLAG_INVENTORY) &&
(ctx->flags & NFCV_REQ_FLAG_ADDRESS);
ctx->advanced = (ctx->command >= NFCV_CMD_ADVANCED);
ctx->address_offset = 2 + (ctx->advanced ? 1 : 0);
ctx->payload_offset = ctx->address_offset + (ctx->addressed ? NFCV_UID_LENGTH : 0);
ctx->response_flags = NfcVSendFlagsSof | NfcVSendFlagsCrc | NfcVSendFlagsEof;
ctx->send_time = nfcv_data->eof_timestamp + NFCV_FDT_FC(4380);
if(ctx->flags & NFCV_REQ_FLAG_DATA_RATE) {
ctx->response_flags |= NfcVSendFlagsHighRate;
}
if(ctx->flags & NFCV_REQ_FLAG_SUB_CARRIER) {
ctx->response_flags |= NfcVSendFlagsTwoSubcarrier;
}
if(ctx->payload_offset + 2 > nfcv_data->frame_length) {
#ifdef NFCV_VERBOSE
FURI_LOG_D(TAG, "command 0x%02X, but packet is too short", ctx->command);
#endif
return;
}
/* standard behavior is implemented */
if(ctx->addressed) {
uint8_t* address = &nfcv_data->frame[ctx->address_offset];
if(nfcv_revuidcmp(address, nfc_data->uid)) {
#ifdef NFCV_VERBOSE
FURI_LOG_D(TAG, "addressed command 0x%02X, but not for us:", ctx->command);
FURI_LOG_D(
TAG,
" dest: %02X%02X%02X%02X%02X%02X%02X%02X",
address[7],
address[6],
address[5],
address[4],
address[3],
address[2],
address[1],
address[0]);
FURI_LOG_D(
TAG,
" our UID: %02X%02X%02X%02X%02X%02X%02X%02X",
nfc_data->uid[0],
nfc_data->uid[1],
nfc_data->uid[2],
nfc_data->uid[3],
nfc_data->uid[4],
nfc_data->uid[5],
nfc_data->uid[6],
nfc_data->uid[7]);
#endif
return;
}
}
if(ctx->selected && !nfcv_data->selected) {
#ifdef NFCV_VERBOSE
FURI_LOG_D(
TAG,
"selected card shall execute command 0x%02X, but we were not selected",
ctx->command);
#endif
return;
}
/* then give control to the card subtype specific protocol filter */
if(ctx->emu_protocol_filter != NULL) {
if(ctx->emu_protocol_filter(tx_rx, nfc_data, nfcv_data)) {
if(strlen(nfcv_data->last_command) > 0) {
#ifdef NFCV_VERBOSE
FURI_LOG_D(
TAG, "Received command %s (handled by filter)", nfcv_data->last_command);
#endif
}
return;
}
}
switch(ctx->command) {
case NFCV_CMD_INVENTORY: {
bool respond = false;
if(ctx->flags & NFCV_REQ_FLAG_AFI) {
uint8_t afi = nfcv_data->frame[ctx->payload_offset];
if(afi == nfcv_data->afi) {
respond = true;
}
} else {
respond = true;
}
if(!nfcv_data->quiet && respond) {
int buffer_pos = 0;
ctx->response_buffer[buffer_pos++] = NFCV_NOERROR;
ctx->response_buffer[buffer_pos++] = nfcv_data->dsfid;
nfcv_revuidcpy(&ctx->response_buffer[buffer_pos], nfc_data->uid);
buffer_pos += NFCV_UID_LENGTH;
nfcv_emu_send(
tx_rx,
nfcv_data,
ctx->response_buffer,
buffer_pos,
ctx->response_flags,
ctx->send_time);
snprintf(nfcv_data->last_command, sizeof(nfcv_data->last_command), "INVENTORY");
} else {
snprintf(
nfcv_data->last_command, sizeof(nfcv_data->last_command), "INVENTORY (quiet)");
}
break;
}
case NFCV_CMD_STAY_QUIET: {
snprintf(nfcv_data->last_command, sizeof(nfcv_data->last_command), "STAYQUIET");
nfcv_data->quiet = true;
break;
}
case NFCV_CMD_LOCK_BLOCK: {
uint8_t block = nfcv_data->frame[ctx->payload_offset];
nfcv_data->security_status[block] |= 0x01;
nfcv_data->modified = true;
ctx->response_buffer[0] = NFCV_NOERROR;
nfcv_emu_send(
tx_rx, nfcv_data, ctx->response_buffer, 1, ctx->response_flags, ctx->send_time);
snprintf(nfcv_data->last_command, sizeof(nfcv_data->last_command), "LOCK BLOCK %d", block);
break;
}
case NFCV_CMD_WRITE_DSFID: {
uint8_t id = nfcv_data->frame[ctx->payload_offset];
if(!(nfcv_data->security_status[0] & NfcVLockBitDsfid)) {
nfcv_data->dsfid = id;
nfcv_data->modified = true;
ctx->response_buffer[0] = NFCV_NOERROR;
nfcv_emu_send(
tx_rx, nfcv_data, ctx->response_buffer, 1, ctx->response_flags, ctx->send_time);
}
snprintf(nfcv_data->last_command, sizeof(nfcv_data->last_command), "WRITE DSFID %02X", id);
break;
}
case NFCV_CMD_WRITE_AFI: {
uint8_t id = nfcv_data->frame[ctx->payload_offset];
if(!(nfcv_data->security_status[0] & NfcVLockBitAfi)) {
nfcv_data->afi = id;
nfcv_data->modified = true;
ctx->response_buffer[0] = NFCV_NOERROR;
nfcv_emu_send(
tx_rx, nfcv_data, ctx->response_buffer, 1, ctx->response_flags, ctx->send_time);
}
snprintf(nfcv_data->last_command, sizeof(nfcv_data->last_command), "WRITE AFI %02X", id);
break;
}
case NFCV_CMD_LOCK_DSFID: {
if(!(nfcv_data->security_status[0] & NfcVLockBitDsfid)) {
nfcv_data->security_status[0] |= NfcVLockBitDsfid;
nfcv_data->modified = true;
ctx->response_buffer[0] = NFCV_NOERROR;
nfcv_emu_send(
tx_rx, nfcv_data, ctx->response_buffer, 1, ctx->response_flags, ctx->send_time);
}
snprintf(nfcv_data->last_command, sizeof(nfcv_data->last_command), "LOCK DSFID");
break;
}
case NFCV_CMD_LOCK_AFI: {
if(!(nfcv_data->security_status[0] & NfcVLockBitAfi)) {
nfcv_data->security_status[0] |= NfcVLockBitAfi;
nfcv_data->modified = true;
ctx->response_buffer[0] = NFCV_NOERROR;
nfcv_emu_send(
tx_rx, nfcv_data, ctx->response_buffer, 1, ctx->response_flags, ctx->send_time);
}
snprintf(nfcv_data->last_command, sizeof(nfcv_data->last_command), "LOCK AFI");
break;
}
case NFCV_CMD_SELECT: {
ctx->response_buffer[0] = NFCV_NOERROR;
nfcv_data->selected = true;
nfcv_data->quiet = false;
nfcv_emu_send(
tx_rx, nfcv_data, ctx->response_buffer, 1, ctx->response_flags, ctx->send_time);
snprintf(nfcv_data->last_command, sizeof(nfcv_data->last_command), "SELECT");
break;
}
case NFCV_CMD_RESET_TO_READY: {
ctx->response_buffer[0] = NFCV_NOERROR;
nfcv_data->quiet = false;
nfcv_emu_send(
tx_rx, nfcv_data, ctx->response_buffer, 1, ctx->response_flags, ctx->send_time);
snprintf(nfcv_data->last_command, sizeof(nfcv_data->last_command), "RESET_TO_READY");
break;
}
case NFCV_CMD_READ_MULTI_BLOCK:
case NFCV_CMD_READ_BLOCK: {
uint8_t block = nfcv_data->frame[ctx->payload_offset];
uint8_t blocks = 1;
if(ctx->command == NFCV_CMD_READ_MULTI_BLOCK) {
blocks = nfcv_data->frame[ctx->payload_offset + 1] + 1;
}
if(block + blocks <= nfcv_data->block_num) {
uint8_t buffer_pos = 0;
ctx->response_buffer[buffer_pos++] = NFCV_NOERROR;
for(int block_index = 0; block_index < blocks; block_index++) {
int block_current = block + block_index;
/* prepend security status */
if(ctx->flags & NFCV_REQ_FLAG_OPTION) {
ctx->response_buffer[buffer_pos++] =
nfcv_data->security_status[1 + block_current];
}
/* then the data block */
memcpy(
&ctx->response_buffer[buffer_pos],
&nfcv_data->data[nfcv_data->block_size * block_current],
nfcv_data->block_size);
buffer_pos += nfcv_data->block_size;
}
nfcv_emu_send(
tx_rx,
nfcv_data,
ctx->response_buffer,
buffer_pos,
ctx->response_flags,
ctx->send_time);
} else {
ctx->response_buffer[0] = NFCV_RES_FLAG_ERROR;
ctx->response_buffer[1] = NFCV_ERROR_GENERIC;
nfcv_emu_send(
tx_rx, nfcv_data, ctx->response_buffer, 2, ctx->response_flags, ctx->send_time);
}
snprintf(nfcv_data->last_command, sizeof(nfcv_data->last_command), "READ BLOCK %d", block);
break;
}
case NFCV_CMD_WRITE_MULTI_BLOCK:
case NFCV_CMD_WRITE_BLOCK: {
uint8_t blocks = 1;
uint8_t block = nfcv_data->frame[ctx->payload_offset];
uint8_t data_pos = ctx->payload_offset + 1;
if(ctx->command == NFCV_CMD_WRITE_MULTI_BLOCK) {
blocks = nfcv_data->frame[data_pos] + 1;
data_pos++;
}
uint8_t* data = &nfcv_data->frame[data_pos];
uint32_t data_len = nfcv_data->block_size * blocks;
if((block + blocks) <= nfcv_data->block_num &&
(data_pos + data_len + 2) == nfcv_data->frame_length) {
ctx->response_buffer[0] = NFCV_NOERROR;
memcpy(
&nfcv_data->data[nfcv_data->block_size * block],
&nfcv_data->frame[data_pos],
data_len);
nfcv_data->modified = true;
nfcv_emu_send(
tx_rx, nfcv_data, ctx->response_buffer, 1, ctx->response_flags, ctx->send_time);
} else {
ctx->response_buffer[0] = NFCV_RES_FLAG_ERROR;
ctx->response_buffer[1] = NFCV_ERROR_GENERIC;
nfcv_emu_send(
tx_rx, nfcv_data, ctx->response_buffer, 2, ctx->response_flags, ctx->send_time);
}
if(ctx->command == NFCV_CMD_WRITE_MULTI_BLOCK) {
snprintf(
nfcv_data->last_command,
sizeof(nfcv_data->last_command),
"WRITE MULTI BLOCK %d, %d blocks",
block,
blocks);
} else {
snprintf(
nfcv_data->last_command,
sizeof(nfcv_data->last_command),
"WRITE BLOCK %d <- %02X %02X %02X %02X",
block,
data[0],
data[1],
data[2],
data[3]);
}
break;
}
case NFCV_CMD_GET_SYSTEM_INFO: {
int buffer_pos = 0;
ctx->response_buffer[buffer_pos++] = NFCV_NOERROR;
ctx->response_buffer[buffer_pos++] = NFCV_SYSINFO_FLAG_DSFID | NFCV_SYSINFO_FLAG_AFI |
NFCV_SYSINFO_FLAG_MEMSIZE | NFCV_SYSINFO_FLAG_ICREF;
nfcv_revuidcpy(&ctx->response_buffer[buffer_pos], nfc_data->uid);
buffer_pos += NFCV_UID_LENGTH;
ctx->response_buffer[buffer_pos++] = nfcv_data->dsfid; /* DSFID */
ctx->response_buffer[buffer_pos++] = nfcv_data->afi; /* AFI */
ctx->response_buffer[buffer_pos++] = nfcv_data->block_num - 1; /* number of blocks */
ctx->response_buffer[buffer_pos++] = nfcv_data->block_size - 1; /* block size */
ctx->response_buffer[buffer_pos++] = nfcv_data->ic_ref; /* IC reference */
nfcv_emu_send(
tx_rx,
nfcv_data,
ctx->response_buffer,
buffer_pos,
ctx->response_flags,
ctx->send_time);
snprintf(nfcv_data->last_command, sizeof(nfcv_data->last_command), "SYSTEMINFO");
break;
}
case NFCV_CMD_CUST_ECHO_MODE: {
ctx->response_buffer[0] = NFCV_NOERROR;
nfcv_data->echo_mode = true;
nfcv_emu_send(
tx_rx, nfcv_data, ctx->response_buffer, 1, ctx->response_flags, ctx->send_time);
snprintf(nfcv_data->last_command, sizeof(nfcv_data->last_command), "ECHO mode");
break;
}
case NFCV_CMD_CUST_ECHO_DATA: {
nfcv_emu_send(
tx_rx,
nfcv_data,
&nfcv_data->frame[ctx->payload_offset],
nfcv_data->frame_length - ctx->payload_offset - 2,
NfcVSendFlagsSof | NfcVSendFlagsHighRate | NfcVSendFlagsEof,
ctx->send_time);
snprintf(nfcv_data->last_command, sizeof(nfcv_data->last_command), "ECHO data");
break;
}
default:
snprintf(
nfcv_data->last_command,
sizeof(nfcv_data->last_command),
"unsupported: %02X",
ctx->command);
break;
}
if(strlen(nfcv_data->last_command) > 0) {
#ifdef NFCV_VERBOSE
FURI_LOG_D(TAG, "Received command %s", nfcv_data->last_command);
#endif
}
}
void nfcv_emu_sniff_packet(
FuriHalNfcTxRxContext* tx_rx,
FuriHalNfcDevData* nfc_data,
void* nfcv_data_in) {
furi_assert(tx_rx);
furi_assert(nfc_data);
furi_assert(nfcv_data_in);
NfcVData* nfcv_data = (NfcVData*)nfcv_data_in;
NfcVEmuProtocolCtx* ctx = nfcv_data->emu_protocol_ctx;
if(nfcv_data->frame_length < 2) {
return;
}
/* parse the frame data for the upcoming part 3 handling */
ctx->flags = nfcv_data->frame[0];
ctx->command = nfcv_data->frame[1];
ctx->selected = (ctx->flags & NFCV_REQ_FLAG_SELECT);
ctx->addressed = !(ctx->flags & NFCV_REQ_FLAG_INVENTORY) &&
(ctx->flags & NFCV_REQ_FLAG_ADDRESS);
ctx->advanced = (ctx->command >= NFCV_CMD_ADVANCED);
ctx->address_offset = 2 + (ctx->advanced ? 1 : 0);
ctx->payload_offset = ctx->address_offset + (ctx->addressed ? NFCV_UID_LENGTH : 0);
char flags_string[5];
snprintf(
flags_string,
5,
"%c%c%c%d",
(ctx->flags & NFCV_REQ_FLAG_INVENTORY) ?
'I' :
(ctx->addressed ? 'A' : (ctx->selected ? 'S' : '*')),
ctx->advanced ? 'X' : ' ',
(ctx->flags & NFCV_REQ_FLAG_DATA_RATE) ? 'h' : 'l',
(ctx->flags & NFCV_REQ_FLAG_SUB_CARRIER) ? 2 : 1);
switch(ctx->command) {
case NFCV_CMD_INVENTORY: {
snprintf(
nfcv_data->last_command, sizeof(nfcv_data->last_command), "%s INVENTORY", flags_string);
break;
}
case NFCV_CMD_STAY_QUIET: {
snprintf(
nfcv_data->last_command, sizeof(nfcv_data->last_command), "%s STAYQUIET", flags_string);
nfcv_data->quiet = true;
break;
}
case NFCV_CMD_LOCK_BLOCK: {
uint8_t block = nfcv_data->frame[ctx->payload_offset];
snprintf(
nfcv_data->last_command,
sizeof(nfcv_data->last_command),
"%s LOCK %d",
flags_string,
block);
break;
}
case NFCV_CMD_WRITE_DSFID: {
uint8_t id = nfcv_data->frame[ctx->payload_offset];
snprintf(
nfcv_data->last_command,
sizeof(nfcv_data->last_command),
"%s WR DSFID %d",
flags_string,
id);
break;
}
case NFCV_CMD_WRITE_AFI: {
uint8_t id = nfcv_data->frame[ctx->payload_offset];
snprintf(
nfcv_data->last_command,
sizeof(nfcv_data->last_command),
"%s WR AFI %d",
flags_string,
id);
break;
}
case NFCV_CMD_LOCK_DSFID: {
snprintf(
nfcv_data->last_command,
sizeof(nfcv_data->last_command),
"%s LOCK DSFID",
flags_string);
break;
}
case NFCV_CMD_LOCK_AFI: {
snprintf(
nfcv_data->last_command, sizeof(nfcv_data->last_command), "%s LOCK AFI", flags_string);
break;
}
case NFCV_CMD_SELECT: {
snprintf(
nfcv_data->last_command, sizeof(nfcv_data->last_command), "%s SELECT", flags_string);
break;
}
case NFCV_CMD_RESET_TO_READY: {
snprintf(
nfcv_data->last_command, sizeof(nfcv_data->last_command), "%s RESET", flags_string);
break;
}
case NFCV_CMD_READ_MULTI_BLOCK:
case NFCV_CMD_READ_BLOCK: {
uint8_t block = nfcv_data->frame[ctx->payload_offset];
uint8_t blocks = 1;
if(ctx->command == NFCV_CMD_READ_MULTI_BLOCK) {
blocks = nfcv_data->frame[ctx->payload_offset + 1] + 1;
}
snprintf(
nfcv_data->last_command,
sizeof(nfcv_data->last_command),
"%s READ %d cnt: %d",
flags_string,
block,
blocks);
break;
}
case NFCV_CMD_WRITE_MULTI_BLOCK:
case NFCV_CMD_WRITE_BLOCK: {
uint8_t block = nfcv_data->frame[ctx->payload_offset];
uint8_t blocks = 1;
uint8_t data_pos = 1;
if(ctx->command == NFCV_CMD_WRITE_MULTI_BLOCK) {
blocks = nfcv_data->frame[ctx->payload_offset + 1] + 1;
data_pos++;
}
uint8_t* data = &nfcv_data->frame[ctx->payload_offset + data_pos];
if(ctx->command == NFCV_CMD_WRITE_MULTI_BLOCK) {
snprintf(
nfcv_data->last_command,
sizeof(nfcv_data->last_command),
"%s WRITE %d, cnd %d",
flags_string,
block,
blocks);
} else {
snprintf(
nfcv_data->last_command,
sizeof(nfcv_data->last_command),
"%s WRITE %d %02X %02X %02X %02X",
flags_string,
block,
data[0],
data[1],
data[2],
data[3]);
}
break;
}
case NFCV_CMD_GET_SYSTEM_INFO: {
snprintf(
nfcv_data->last_command,
sizeof(nfcv_data->last_command),
"%s SYSTEMINFO",
flags_string);
break;
}
default:
snprintf(
nfcv_data->last_command,
sizeof(nfcv_data->last_command),
"%s unsupported: %02X",
flags_string,
ctx->command);
break;
}
if(strlen(nfcv_data->last_command) > 0) {
FURI_LOG_D(TAG, "Received command %s", nfcv_data->last_command);
}
}
void nfcv_emu_init(FuriHalNfcDevData* nfc_data, NfcVData* nfcv_data) {
furi_assert(nfc_data);
furi_assert(nfcv_data);
if(!nfcv_emu_alloc(nfcv_data)) {
FURI_LOG_E(TAG, "Failed to allocate structures");
nfcv_data->ready = false;
return;
}
strcpy(nfcv_data->last_command, "");
nfcv_data->quiet = false;
nfcv_data->selected = false;
nfcv_data->modified = false;
/* everything is initialized */
nfcv_data->ready = true;
/* ensure the GPIO is already in unmodulated state */
furi_hal_gpio_init(&gpio_spi_r_mosi, GpioModeOutputPushPull, GpioPullNo, GpioSpeedVeryHigh);
furi_hal_gpio_write(&gpio_spi_r_mosi, GPIO_LEVEL_UNMODULATED);
rfal_platform_spi_acquire();
/* stop operation to configure for transparent and passive mode */
st25r3916ExecuteCommand(ST25R3916_CMD_STOP);
/* set enable, rx_enable and field detector enable */
st25r3916WriteRegister(
ST25R3916_REG_OP_CONTROL,
ST25R3916_REG_OP_CONTROL_en | ST25R3916_REG_OP_CONTROL_rx_en |
ST25R3916_REG_OP_CONTROL_en_fd_auto_efd);
/* explicitely set the modulation resistor in case system config changes for some reason */
st25r3916WriteRegister(
ST25R3916_REG_PT_MOD,
(0 << ST25R3916_REG_PT_MOD_ptm_res_shift) | (15 << ST25R3916_REG_PT_MOD_pt_res_shift));
/* target mode: target, other fields do not have any effect as we use transparent mode */
st25r3916WriteRegister(ST25R3916_REG_MODE, ST25R3916_REG_MODE_targ);
/* let us modulate the field using MOSI, read ASK modulation using IRQ */
st25r3916ExecuteCommand(ST25R3916_CMD_TRANSPARENT_MODE);
furi_hal_spi_bus_handle_deinit(&furi_hal_spi_bus_handle_nfc);
/* if not set already, initialize the default protocol handler */
if(!nfcv_data->emu_protocol_ctx) {
nfcv_data->emu_protocol_ctx = malloc(sizeof(NfcVEmuProtocolCtx));
if(nfcv_data->sub_type == NfcVTypeSniff) {
nfcv_data->emu_protocol_handler = &nfcv_emu_sniff_packet;
} else {
nfcv_data->emu_protocol_handler = &nfcv_emu_handle_packet;
}
}
FURI_LOG_D(TAG, "Starting NfcV emulation");
FURI_LOG_D(
TAG,
" UID: %02X %02X %02X %02X %02X %02X %02X %02X",
nfc_data->uid[0],
nfc_data->uid[1],
nfc_data->uid[2],
nfc_data->uid[3],
nfc_data->uid[4],
nfc_data->uid[5],
nfc_data->uid[6],
nfc_data->uid[7]);
switch(nfcv_data->sub_type) {
case NfcVTypeSlixL:
FURI_LOG_D(TAG, " Card type: SLIX-L");
slix_l_prepare(nfcv_data);
break;
case NfcVTypeSlixS:
FURI_LOG_D(TAG, " Card type: SLIX-S");
slix_s_prepare(nfcv_data);
break;
case NfcVTypeSlix2:
FURI_LOG_D(TAG, " Card type: SLIX2");
slix2_prepare(nfcv_data);
break;
case NfcVTypeSlix:
FURI_LOG_D(TAG, " Card type: SLIX");
slix_prepare(nfcv_data);
break;
case NfcVTypePlain:
FURI_LOG_D(TAG, " Card type: Plain");
break;
case NfcVTypeSniff:
FURI_LOG_D(TAG, " Card type: Sniffing");
break;
}
/* allocate a 512 edge buffer, more than enough */
nfcv_data->emu_air.reader_signal =
pulse_reader_alloc(&gpio_nfc_irq_rfid_pull, NFCV_PULSE_BUFFER);
/* timebase shall be 1 ns */
pulse_reader_set_timebase(nfcv_data->emu_air.reader_signal, PulseReaderUnitNanosecond);
/* and configure to already calculate the number of bits */
pulse_reader_set_bittime(nfcv_data->emu_air.reader_signal, NFCV_PULSE_DURATION_NS);
/* this IO is fed into the µC via a diode, so we need a pulldown */
pulse_reader_set_pull(nfcv_data->emu_air.reader_signal, GpioPullDown);
/* start sampling */
pulse_reader_start(nfcv_data->emu_air.reader_signal);
}
void nfcv_emu_deinit(NfcVData* nfcv_data) {
furi_assert(nfcv_data);
furi_hal_spi_bus_handle_init(&furi_hal_spi_bus_handle_nfc);
nfcv_emu_free(nfcv_data);
if(nfcv_data->emu_protocol_ctx) {
free(nfcv_data->emu_protocol_ctx);
nfcv_data->emu_protocol_ctx = NULL;
}
/* set registers back to how we found them */
st25r3916WriteRegister(ST25R3916_REG_OP_CONTROL, 0x00);
st25r3916WriteRegister(ST25R3916_REG_MODE, 0x08);
rfal_platform_spi_release();
}
bool nfcv_emu_loop(
FuriHalNfcTxRxContext* tx_rx,
FuriHalNfcDevData* nfc_data,
NfcVData* nfcv_data,
uint32_t timeout_ms) {
furi_assert(tx_rx);
furi_assert(nfc_data);
furi_assert(nfcv_data);
bool ret = false;
uint32_t frame_state = NFCV_FRAME_STATE_SOF1;
uint32_t periods_previous = 0;
uint32_t frame_pos = 0;
uint32_t byte_value = 0;
uint32_t bits_received = 0;
uint32_t timeout = timeout_ms * 1000;
bool wait_for_pulse = false;
if(!nfcv_data->ready) {
return false;
}
#ifdef NFCV_DIAGNOSTIC_DUMPS
uint8_t period_buffer[NFCV_DIAGNOSTIC_DUMP_SIZE];
uint32_t period_buffer_pos = 0;
#endif
while(true) {
uint32_t periods = pulse_reader_receive(nfcv_data->emu_air.reader_signal, timeout);
uint32_t timestamp = DWT->CYCCNT;
/* when timed out, reset to SOF state */
if(periods == PULSE_READER_NO_EDGE || periods == PULSE_READER_LOST_EDGE) {
break;
}
#ifdef NFCV_DIAGNOSTIC_DUMPS
if(period_buffer_pos < sizeof(period_buffer)) {
period_buffer[period_buffer_pos++] = periods;
}
#endif
/* short helper for detecting a pulse position */
if(wait_for_pulse) {
wait_for_pulse = false;
if(periods != 1) {
frame_state = NFCV_FRAME_STATE_RESET;
}
continue;
}
switch(frame_state) {
case NFCV_FRAME_STATE_SOF1:
if(periods == 1) {
frame_state = NFCV_FRAME_STATE_SOF2;
} else {
frame_state = NFCV_FRAME_STATE_SOF1;
break;
}
break;
case NFCV_FRAME_STATE_SOF2:
/* waiting for the second low period, telling us about coding */
if(periods == 6) {
frame_state = NFCV_FRAME_STATE_CODING_256;
periods_previous = 0;
wait_for_pulse = true;
} else if(periods == 4) {
frame_state = NFCV_FRAME_STATE_CODING_4;
periods_previous = 2;
wait_for_pulse = true;
} else {
frame_state = NFCV_FRAME_STATE_RESET;
}
break;
case NFCV_FRAME_STATE_CODING_256:
if(periods_previous > periods) {
frame_state = NFCV_FRAME_STATE_RESET;
break;
}
/* previous symbol left us with some pulse periods */
periods -= periods_previous;
if(periods > 512) {
frame_state = NFCV_FRAME_STATE_RESET;
break;
} else if(periods == 2) {
frame_state = NFCV_FRAME_STATE_EOF;
break;
}
periods_previous = 512 - (periods + 1);
byte_value = (periods - 1) / 2;
if(frame_pos < NFCV_FRAMESIZE_MAX) {
nfcv_data->frame[frame_pos++] = (uint8_t)byte_value;
}
wait_for_pulse = true;
break;
case NFCV_FRAME_STATE_CODING_4:
if(periods_previous > periods) {
frame_state = NFCV_FRAME_STATE_RESET;
break;
}
/* previous symbol left us with some pulse periods */
periods -= periods_previous;
periods_previous = 0;
byte_value >>= 2;
bits_received += 2;
if(periods == 1) {
byte_value |= 0x00 << 6;
periods_previous = 6;
} else if(periods == 3) {
byte_value |= 0x01 << 6;
periods_previous = 4;
} else if(periods == 5) {
byte_value |= 0x02 << 6;
periods_previous = 2;
} else if(periods == 7) {
byte_value |= 0x03 << 6;
periods_previous = 0;
} else if(periods == 2) {
frame_state = NFCV_FRAME_STATE_EOF;
break;
} else {
frame_state = NFCV_FRAME_STATE_RESET;
break;
}
if(bits_received >= 8) {
if(frame_pos < NFCV_FRAMESIZE_MAX) {
nfcv_data->frame[frame_pos++] = (uint8_t)byte_value;
}
bits_received = 0;
}
wait_for_pulse = true;
break;
}
/* post-state-machine cleanup and reset */
if(frame_state == NFCV_FRAME_STATE_RESET) {
frame_state = NFCV_FRAME_STATE_SOF1;
} else if(frame_state == NFCV_FRAME_STATE_EOF) {
nfcv_data->frame_length = frame_pos;
nfcv_data->eof_timestamp = timestamp;
break;
}
}
if(frame_state == NFCV_FRAME_STATE_EOF) {
/* we know that this code uses TIM2, so stop pulse reader */
pulse_reader_stop(nfcv_data->emu_air.reader_signal);
if(tx_rx->sniff_rx) {
tx_rx->sniff_rx(nfcv_data->frame, frame_pos * 8, false, tx_rx->sniff_context);
}
nfcv_data->emu_protocol_handler(tx_rx, nfc_data, nfcv_data);
pulse_reader_start(nfcv_data->emu_air.reader_signal);
ret = true;
}
#ifdef NFCV_VERBOSE
else {
if(frame_state != NFCV_FRAME_STATE_SOF1) {
FURI_LOG_T(TAG, "leaving while in state: %lu", frame_state);
}
}
#endif
#ifdef NFCV_DIAGNOSTIC_DUMPS
if(period_buffer_pos) {
FURI_LOG_T(TAG, "pulses:");
for(uint32_t pos = 0; pos < period_buffer_pos; pos++) {
FURI_LOG_T(TAG, " #%lu: %u", pos, period_buffer[pos]);
}
}
#endif
return ret;
}
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