unleashed-firmware/applications/main/nfc/plugins/supported_cards/myki.c
2024-02-14 18:34:26 +03:00

117 lines
3.8 KiB
C

/* myki.c - Parser for myki cards (Melbourne, Australia).
*
* Based on the code by Emily Trau (https://github.com/emilytrau)
* Original pull request URL: https://github.com/flipperdevices/flipperzero-firmware/pull/2326
* Reference: https://github.com/metrodroid/metrodroid/wiki/Myki
*/
#include "nfc_supported_card_plugin.h"
#include <flipper_application.h>
#include <lib/nfc/protocols/mf_desfire/mf_desfire.h>
static const MfDesfireApplicationId myki_app_id = {.data = {0x00, 0x11, 0xf2}};
static const MfDesfireFileId myki_file_id = 0x0f;
static uint8_t myki_calculate_luhn(uint64_t number) {
// https://en.wikipedia.org/wiki/Luhn_algorithm
// Drop existing check digit to form payload
uint64_t payload = number / 10;
int sum = 0;
int position = 0;
while(payload > 0) {
int digit = payload % 10;
if(position % 2 == 0) {
digit *= 2;
}
if(digit > 9) {
digit = (digit / 10) + (digit % 10);
}
sum += digit;
payload /= 10;
position++;
}
return (10 - (sum % 10)) % 10;
}
static bool myki_parse(const NfcDevice* device, FuriString* parsed_data) {
furi_assert(device);
furi_assert(parsed_data);
bool parsed = false;
do {
const MfDesfireData* data = nfc_device_get_data(device, NfcProtocolMfDesfire);
const MfDesfireApplication* app = mf_desfire_get_application(data, &myki_app_id);
if(app == NULL) break;
typedef struct {
uint32_t top;
uint32_t bottom;
} MykiFile;
const MfDesfireFileSettings* file_settings =
mf_desfire_get_file_settings(app, &myki_file_id);
if(file_settings == NULL || file_settings->type != MfDesfireFileTypeStandard ||
file_settings->data.size < sizeof(MykiFile))
break;
const MfDesfireFileData* file_data = mf_desfire_get_file_data(app, &myki_file_id);
if(file_data == NULL) break;
const MykiFile* myki_file = simple_array_cget_data(file_data->data);
// All myki card numbers are prefixed with "308425"
if(myki_file->top != 308425UL) break;
// Card numbers are always 15 digits in length
if(myki_file->bottom < 10000000UL || myki_file->bottom >= 100000000UL) break;
uint64_t card_number = myki_file->top * 1000000000ULL + myki_file->bottom * 10UL;
// Stored card number doesn't include check digit
card_number += myki_calculate_luhn(card_number);
furi_string_set(parsed_data, "\e#myki\n");
// Stylise card number according to the physical card
char card_string[20];
snprintf(card_string, sizeof(card_string), "%llu", card_number);
// Digit count in each space-separated group
static const uint8_t digit_count[] = {1, 5, 4, 4, 1};
for(uint32_t i = 0, k = 0; i < COUNT_OF(digit_count); k += digit_count[i++]) {
for(uint32_t j = 0; j < digit_count[i]; ++j) {
furi_string_push_back(parsed_data, card_string[j + k]);
}
furi_string_push_back(parsed_data, ' ');
}
parsed = true;
} while(false);
return parsed;
}
/* Actual implementation of app<>plugin interface */
static const NfcSupportedCardsPlugin myki_plugin = {
.protocol = NfcProtocolMfDesfire,
.verify = NULL,
.read = NULL,
.parse = myki_parse,
};
/* Plugin descriptor to comply with basic plugin specification */
static const FlipperAppPluginDescriptor myki_plugin_descriptor = {
.appid = NFC_SUPPORTED_CARD_PLUGIN_APP_ID,
.ep_api_version = NFC_SUPPORTED_CARD_PLUGIN_API_VERSION,
.entry_point = &myki_plugin,
};
/* Plugin entry point - must return a pointer to const descriptor */
const FlipperAppPluginDescriptor* myki_plugin_ep() {
return &myki_plugin_descriptor;
}