/*
* opal.c - Parser for Opal card (Sydney, Australia).
*
* Copyright 2023 Michael Farrell <micolous+git@gmail.com>
*
* This will only read "standard" MIFARE DESFire-based Opal cards. Free travel
* cards (including School Opal cards, veteran, vision-impaired persons and
* TfNSW employees' cards) and single-trip tickets are MIFARE Ultralight C
* cards and not supported.
*
* Reference: https://github.com/metrodroid/metrodroid/wiki/Opal
*
* Note: The card values are all little-endian (like Flipper), but the above
* reference was originally written based on Java APIs, which are big-endian.
* This implementation presumes a little-endian system.
*
* This program is free software: you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "nfc_supported_card.h"
#include "opal.h"
#include <applications/services/locale/locale.h>
#include <gui/modules/widget.h>
#include <nfc_worker_i.h>
#include <furi_hal.h>
static const uint8_t opal_aid[3] = {0x31, 0x45, 0x53};
static const char* opal_modes[5] =
{"Rail / Metro", "Ferry / Light Rail", "Bus", "Unknown mode", "Manly Ferry"};
static const char* opal_usages[14] = {
"New / Unused",
"Tap on: new journey",
"Tap on: transfer from same mode",
"Tap on: transfer from other mode",
"", // Manly Ferry: new journey
"", // Manly Ferry: transfer from ferry
"", // Manly Ferry: transfer from other
"Tap off: distance fare",
"Tap off: flat fare",
"Automated tap off: failed to tap off",
"Tap off: end of trip without start",
"Tap off: reversal",
"Tap on: rejected",
"Unknown usage",
};
// Opal file 0x7 structure. Assumes a little-endian CPU.
typedef struct __attribute__((__packed__)) {
uint32_t serial : 32;
uint8_t check_digit : 4;
bool blocked : 1;
uint16_t txn_number : 16;
int32_t balance : 21;
uint16_t days : 15;
uint16_t minutes : 11;
uint8_t mode : 3;
uint16_t usage : 4;
bool auto_topup : 1;
uint8_t weekly_journeys : 4;
uint16_t checksum : 16;
} OpalFile;
static_assert(sizeof(OpalFile) == 16);
// Converts an Opal timestamp to FuriHalRtcDateTime.
//
// Opal measures days since 1980-01-01 and minutes since midnight, and presumes
// all days are 1440 minutes.
void opal_date_time_to_furi(uint16_t days, uint16_t minutes, FuriHalRtcDateTime* out) {
if(!out) return;
uint16_t diy;
out->year = 1980;
out->month = 1;
// 1980-01-01 is a Tuesday
out->weekday = ((days + 1) % 7) + 1;
out->hour = minutes / 60;
out->minute = minutes % 60;
out->second = 0;
// What year is it?
for(;;) {
diy = furi_hal_rtc_get_days_per_year(out->year);
if(days < diy) break;
days -= diy;
out->year++;
}
// 1-index the day of the year
days++;
// What month is it?
bool is_leap = furi_hal_rtc_is_leap_year(out->year);
for(;;) {
uint8_t dim = furi_hal_rtc_get_days_per_month(is_leap, out->month);
if(days <= dim) break;
days -= dim;
out->month++;
}
out->day = days;
}
bool opal_parser_parse(NfcDeviceData* dev_data) {
if(dev_data->protocol != NfcDeviceProtocolMifareDesfire) {
return false;
}
MifareDesfireApplication* app = mf_df_get_application(&dev_data->mf_df_data, &opal_aid);
if(app == NULL) {
return false;
}
MifareDesfireFile* f = mf_df_get_file(app, 0x07);
if(f == NULL || f->type != MifareDesfireFileTypeStandard || f->settings.data.size != 16 ||
!f->contents) {
return false;
}
OpalFile* o = (OpalFile*)f->contents;
uint8_t serial2 = o->serial / 10000000;
uint16_t serial3 = (o->serial / 1000) % 10000;
uint16_t serial4 = (o->serial % 1000);
if(o->check_digit > 9) {
return false;
}
char* sign = "";
if(o->balance < 0) {
// Negative balance. Make this a positive value again and record the
// sign separately, because then we can handle balances of -99..-1
// cents, as the "dollars" division below would result in a positive
// zero value.
o->balance = abs(o->balance);
sign = "-";
}
uint8_t cents = o->balance % 100;
int32_t dollars = o->balance / 100;
FuriHalRtcDateTime timestamp;
opal_date_time_to_furi(o->days, o->minutes, ×tamp);
if(o->mode >= 3) {
// 3..7 are "reserved", but we use 4 to indicate the Manly Ferry.
o->mode = 3;
}
if(o->usage >= 4 && o->usage <= 6) {
// Usages 4..6 associated with the Manly Ferry, which correspond to
// usages 1..3 for other modes.
o->usage -= 3;
o->mode = 4;
}
const char* mode_str = (o->mode <= 4 ? opal_modes[o->mode] : opal_modes[3]);
const char* usage_str = (o->usage <= 12 ? opal_usages[o->usage] : opal_usages[13]);
furi_string_printf(
dev_data->parsed_data,
"\e#Opal: $%s%ld.%02hu\n3085 22%02hhu %04hu %03hu%01hhu\n%s, %s\n",
sign,
dollars,
cents,
serial2,
serial3,
serial4,
o->check_digit,
mode_str,
usage_str);
FuriString* timestamp_str = furi_string_alloc();
locale_format_date(timestamp_str, ×tamp, locale_get_date_format(), "-");
furi_string_cat(dev_data->parsed_data, timestamp_str);
furi_string_cat_str(dev_data->parsed_data, " at ");
locale_format_time(timestamp_str, ×tamp, locale_get_time_format(), false);
furi_string_cat(dev_data->parsed_data, timestamp_str);
furi_string_free(timestamp_str);
furi_string_cat_printf(
dev_data->parsed_data,
"\nWeekly journeys: %hhu, Txn #%hu\n",
o->weekly_journeys,
o->txn_number);
if(o->auto_topup) {
furi_string_cat_str(dev_data->parsed_data, "Auto-topup enabled\n");
}
if(o->blocked) {
furi_string_cat_str(dev_data->parsed_data, "Card blocked\n");
}
return true;
}
↑ V1081 Argument of abs() function may reach minimal negative value. Such absolute value can't be represented in two's complement. This may result in undefined behavior.
↑ V547 Expression 'o->mode <= 4' is always true.