mirror of
https://github.com/Next-Flip/Momentum-Firmware.git
synced 2026-05-10 05:59:08 -07:00
Parsing function readability refactor
This commit is contained in:
Zachary Weiss
@@ -23,8 +23,6 @@
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* — Reverse engineer passes (sectors 4 & 5?), impl.
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* — Infer transaction flag meanings
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* — Infer remaining unknown bytes in the balance sectors (2 & 3)
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* – ASCII art &/or unified read function for the balance sectors,
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* to improve readability / interpretability by others?
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* — Improve string output formatting, esp. of transaction log
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* — Mapping of buses to garages, and subsequently, route subsets via
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* http://roster.transithistory.org/ data
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@@ -99,11 +97,6 @@
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#define CHARLIE_N_TRIP_HISTORY 10
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#define CHARLIE_N_PASSES 4
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enum CharlieActiveSector {
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CHARLIE_ACTIVE_SECTOR_2,
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CHARLIE_ACTIVE_SECTOR_3,
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};
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typedef struct {
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uint64_t a;
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uint64_t b;
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@@ -163,6 +156,18 @@ typedef struct {
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DateTime end;
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} Pass;
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typedef struct {
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uint16_t n_uses;
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uint8_t active_balance_sector;
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} CounterSector;
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typedef struct {
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Money balance;
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uint16_t type;
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DateTime issued;
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DateTime end_validity;
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} BalanceSector;
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// IdMapping approach borrowed from Jeremy Cooper's 'clipper.c'
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typedef struct {
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uint16_t id;
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@@ -656,7 +661,7 @@ static bool is_debug() {
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}
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// **********************************************************
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// ********************* DATA PARSING ***********************
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// ******************** FIELD PARSING ***********************
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// **********************************************************
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static Money money_parse(
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@@ -677,46 +682,6 @@ static DateTime
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return dt_delta(CHARLIE_EPOCH, ts_charlie * CHARLIE_TIME_DELTA_SECS);
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}
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static uint16_t n_uses(const MfClassicData* data, const enum CharlieActiveSector active_sector) {
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/* First two bytes of applicable block (sector 1, block 1 or 2 depending on active_sector)
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The *lower* of the two values *minus one* is the true use count,
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per DEFCON31 researcher's findings
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*/
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return pos_to_num(data, 1, 1 + active_sector, 0, 2) - 1;
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}
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static enum CharlieActiveSector get_active_sector(const MfClassicData* data) {
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/* Card has two transaction sectors (2 & 3) containing balance data, with two
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corresponding trip counters in 0x50:0x51 & 0x60:0x61 (sector 1, byte 0:1 of blocks 1 & 2).
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The *lower* count variable corresponds to the active sector
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(0x5_ lower -> 2 active, 0x6_ lower -> 3 active)
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Sectors 2 & 3 are (largely) identical, save for trip data.
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Card seems to alternate between the two, with active sector storing
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the current balance & recent trip/transaction, & the inactive sector storing
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the N-1 trip/transaction version of the same data.
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Here I check both the trip count and the stored transaction date,
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for my own sanity, to confirm the active sector.
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*/
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// active sector based on trip counters
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const bool active_trip = n_uses(data, CHARLIE_ACTIVE_SECTOR_2) <=
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n_uses(data, CHARLIE_ACTIVE_SECTOR_3);
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// active sector based on transaction date
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DateTime ds2 = date_parse(data, 2, 0, 1);
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DateTime ds3 = date_parse(data, 3, 0, 1);
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const bool active_date = datetime_datetime_to_timestamp(&ds2) >=
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datetime_datetime_to_timestamp(&ds3);
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// with all tested cards so far, this has been true
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furi_assert(active_trip == active_date);
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return active_trip ? CHARLIE_ACTIVE_SECTOR_2 : CHARLIE_ACTIVE_SECTOR_3;
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}
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static uint16_t type_parse(const MfClassicData* data) {
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/* Card type data stored in the first 10bits of block 1 of sectors 2 & 3 (Block 9 & Block 13, from card start)
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To my knowledge, card type should never change, so we can check either
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@@ -745,12 +710,6 @@ static DateTime end_validity_parse(
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return dt_delta(CHARLIE_EPOCH, ts_charlie_ev * CHARLIE_END_VALID_DELTA_SECS);
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}
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static DateTime
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main_end_validity_parse(const MfClassicData* data, enum CharlieActiveSector active_sec) {
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// primary card type end validity; checked in active sector (probably the same across both 2 & 3)
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return end_validity_parse(data, (active_sec == CHARLIE_ACTIVE_SECTOR_2) ? 2 : 3, 1, 1);
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}
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static Pass
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pass_parse(const MfClassicData* data, uint8_t sector_num, uint8_t block_num, uint8_t byte_num) {
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// WIP; testing only. Speculating it may be structured as follows
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@@ -814,53 +773,100 @@ static Trip
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return (Trip){date, gate, g_flag, fare, f_flag};
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}
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// Manufacturer data (Sector 0)
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//
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// 0 1 2 3 4 5 6 7 8 9 A B C D E F
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// +----.----.----.----+----+----.----.----.----+----+----.----.----.----.----+----+
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// 0x000 | UID |LRC | 88 04 00 C8 |unkn| 00 20 00 00 00 |unkn|
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// +----.----.----.----+----+----.----.----.----+----+----.----.----.----.----+----+
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// 0x010 | 4E 0F 04 10 04 10 04 10 04 10 04 10 04 10 04 10 |
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// +----.----.----.----.----.----.----.----.----.----.----.----.----.----.----.----+
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// 0x020 | ... 00 00 ... |
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// +----.----.----.----.----.----.----.----.----.----.----.----.----.----.----.----+
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// **********************************************************
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// ******************* SECTOR PARSING ***********************
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// **********************************************************
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// Trip/transaction counters (Sector 1)
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//
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// 0 1 2 3 4 5 6 7 8 9 A B C D E F
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// +----.----.----.----.----.----.----.----.----.----.----.----.----.----.----+----+
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// 0x040 | 04 10 23 45 66 77 ... 00 00 ... |
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// +----.----+----+----.----.----.----.----.----.----.----.----.----.----.----+----+
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// 0x050 | uses1 |unkn| ... 00 00 ... |
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// +----.----+----+----.----.----.----.----.----.----.----.----.----.----.----.----+
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// 0x060 | uses2 |unkn| ... 00 00 ... |
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// +----.----+----+----.----.----.----.----.----.----.----.----.----.----.----.----+
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static uint32_t mfg_sector_parse(const MfClassicData* data) {
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// Manufacturer data (Sector 0)
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//
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// 0 1 2 3 4 5 6 7 8 9 A B C D E F
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// +----.----.----.----+----+----.----.----.----+----+----.----.----.----.----+----+
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// 0x000 | UID |LRC | 88 04 00 C8 |unkn| 00 20 00 00 00 |unkn|
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// +----.----.----.----+----+----.----.----.----+----+----.----.----.----.----+----+
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// 0x010 | 4E 0F 04 10 04 10 04 10 04 10 04 10 04 10 04 10 |
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// +----.----.----.----.----.----.----.----.----.----.----.----.----.----.----.----+
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// 0x020 | ... 00 00 ... |
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// +----.----.----.----.----.----.----.----.----.----.----.----.----.----.----.----+
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// Balance / type / last transaction (Sector 2 & 3)
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//
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// 0 1 2 3 4 5 6 7 8 9 A B C D E F
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// +----+----.----.----+----.----+----.----.----+----.----+----.----+----+----.----+
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// 0x080 | 11 | date last | loc last| date issued | 65 00 | unknown | 00 | crc |
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// +----+----.----.----+----+----+----+----+----+----.----+----.----+----+----.----+
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// 0x090 | type |end validity|unkn| balance | 00 | unknown | crc |
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// +----.----.----.----+----+----.----+----+----.----.----.----.----.----+----.----+
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// 0x0A0 | 20 ... 00 00 ... 04 | crc |
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// +----.----.----.----.----.----.----.----.----.----.----.----.----.----+----.----+
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size_t uid_len = 0;
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const uint8_t* uid = mf_classic_get_uid(data, &uid_len);
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const uint32_t card_number = bit_lib_bytes_to_num_be(uid, 4);
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return card_number;
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}
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static CounterSector counter_sector_parse(const MfClassicData* data) {
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// Trip/transaction counters (Sector 1)
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//
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// 0 1 2 3 4 5 6 7 8 9 A B C D E F
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// +----.----.----.----.----.----.----.----.----.----.----.----.----.----.----+----+
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// 0x040 | 04 10 23 45 66 77 ... 00 00 ... |
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// +----.----+----+----.----.----.----.----.----.----.----.----.----.----.----+----+
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// 0x050 | uses1 |unkn| ... 00 00 ... |
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// +----.----+----+----.----.----.----.----.----.----.----.----.----.----.----.----+
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// 0x060 | uses2 |unkn| ... 00 00 ... |
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// +----.----+----+----.----.----.----.----.----.----.----.----.----.----.----.----+
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// Card has two transaction sectors (2 & 3) containing balance data, with two
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// corresponding trip counters in 0x50:0x51 & 0x60:0x61 (sector 1, byte 0:1 of blocks 1 & 2).
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// The *lower* of the two values *minus one* is the true use count,
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// and corresponds to the active balance sector,
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// (0x50 counter lower -> sector 2 active, 0x60 counter lower -> 3 active)
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// per DEFCON31 researcher's findings
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const uint16_t n_uses1 = pos_to_num(data, 1, 1, 0, 2);
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const uint16_t n_uses2 = pos_to_num(data, 1, 2, 0, 2);
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const bool is_sec2_active = n_uses1 <= n_uses2;
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const uint8_t active_sector = is_sec2_active ? 2 : 3;
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const uint16_t n_uses = (is_sec2_active ? n_uses1 : n_uses2) - 1;
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return (CounterSector){n_uses, active_sector};
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}
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static BalanceSector balance_sector_parse(const MfClassicData* data, uint8_t active_sector) {
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// Balance / type / last transaction (Sector 2 or 3)
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//
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// 0 1 2 3 4 5 6 7 8 9 A B C D E F
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// +----+----.----.----+----.----+----.----.----+----.----+----.----+----+----.----+
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// 0x080 | 11 | date last | loc last| date issued | 65 00 | unknown | 00 | crc | 0x0C0
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// +----+----.----.----+----+----+----+----+----+----.----+----.----+----+----.----+
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// 0x090 | type |end validity|unkn| balance | 00 | unknown | crc | 0x0D0
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// +----.----.----.----+----+----.----+----+----.----.----.----.----.----+----.----+
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// 0x0A0 | 20 ... 00 00 ... 04 | crc | 0x0E0
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// +----.----.----.----.----.----.----.----.----.----.----.----.----.----+----.----+
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//
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// "Active" balance sector alternates between 2 and 3
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// Last trip/transaction info in balance sector (date last & loc last)
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// also included in transaction log, hence don't bother to read here
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//
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// Inactive balance sector represent the transaction N-1 balance data
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// (where active sector represents data from transaction N).
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const DateTime issued = date_parse(data, active_sector, 0, 6);
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const DateTime end_validity = end_validity_parse(data, active_sector, 1, 1);
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const uint16_t type = type_parse(data);
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const Money bal = money_parse(data, active_sector, 1, 5);
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return (BalanceSector){bal, type, issued, end_validity};
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}
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static Pass* passes_parse(const MfClassicData* data) {
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// WIP. Read in all speculative passes into array
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// Sectors 4 & 5 speculated to contain pass data,
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// 4 separate fields? active vs inactive sector for 2 passes?
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// Sector 4 visualized below; sector 5 layout the same.
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// Passes, speculative (Sectors 4 &/or 5)
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//
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// 0 1 2 3 4 5 6 7 8 9 A B C D E F
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// +----.----.----.----.----.-+--.----+----.----.----.----.----.-+--.----+----.----+
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// 0x100 | pass0? |0 00 | pass1? |0 00 | crc |
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// 0x100 | pass0? |0 00 | pass1? |0 00 | crc | 0x140
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// +----.----.----.----.----.-+--.----+----.----.----.----.----.-+--.----+----.----+
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// 0x110 | ... 00 00 ... | crc |
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// 0x110 | ... 00 00 ... | crc | 0x150
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// +----.----.----.----.----.----.----.----.----.----.----.----.----.----+----.----+
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// 0x120 | ... 00 ... 05 | crc |
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// 0x120 | ... 00 ... 05 | crc | 0x160
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// +----.----.----.----.----.----.----.----.----.----.----.----.----.----+----.----+
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//
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// WIP. Read in all speculative passes into array
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// 4 separate fields? active vs inactive sector for 2 passes?
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Pass* passes = malloc(sizeof(Pass) * CHARLIE_N_PASSES);
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@@ -872,7 +878,7 @@ static Pass* passes_parse(const MfClassicData* data) {
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}
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static Trip* trips_parse(const MfClassicData* data) {
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// Sectors 6 & 7 store the last 10 trips. Overall layout as follows:
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// Transaction history (Sectors 6–7)
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//
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// 0 1 2 3 4 5 6 7 8 9 A B C D E F
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// +----.----.----.----.----.----.----+----.----.----.----.----.----.----+----.----+
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@@ -885,7 +891,8 @@ static Trip* trips_parse(const MfClassicData* data) {
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// 0x1E0 | ... 00 00 ... | crc |
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// +----.----.----.----.----.----.----.----.----.----.----.----.----.----+----.----+
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//
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//Trips are not sorted, rather, appear to get overwritten sequentially. (eg, sorted modulo array rotation)
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// Transactions are not sorted, rather, appear to get overwritten
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// sequentially. (eg, sorted modulo array rotation)
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Trip* trips = malloc(sizeof(Trip) * CHARLIE_N_TRIP_HISTORY);
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@@ -958,7 +965,7 @@ static DateTime expiry(DateTime iss) {
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}
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return exp;
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}*/
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}
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static bool expired(DateTime expiry, DateTime last_trip) {
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// if a card has sat unused for >2 years, expired (verify this claim?)
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@@ -970,6 +977,7 @@ static bool expired(DateTime expiry, DateTime last_trip) {
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return (ts_exp <= ts_now) | ((ts_now - ts_last) >= (2 * 365 * 24 * 60 * 60));
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}
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*/
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// **********************************************************
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// ****************** STRING FORMATTING *********************
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@@ -1011,7 +1019,7 @@ void pass_format_cat(FuriString* out, Pass pass) {
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void passes_format_cat(FuriString* out, Pass* passes) {
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if(is_debug()) {
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furi_string_cat_printf(out, "\nPasses (DEBUG & WIP):");
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furi_string_cat_printf(out, "\nPasses (DEBUG / WIP):");
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for(size_t i = 0; i < CHARLIE_N_PASSES; i++) {
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if(passes[i].valid) {
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furi_string_cat_printf(out, "\nPass %u", i + 1);
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@@ -1091,43 +1099,38 @@ static bool charliecard_parse(const NfcDevice* device, FuriString* parsed_data)
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// TODO: Verify add'l?
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const enum CharlieActiveSector active_sec_enum = get_active_sector(data);
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const uint8_t active_sector = (active_sec_enum == CHARLIE_ACTIVE_SECTOR_2) ? 2 : 3;
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// parse card data
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const uint32_t card_number = mfg_sector_parse(data);
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const CounterSector counter_sector = counter_sector_parse(data);
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const BalanceSector balance_sector =
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balance_sector_parse(data, counter_sector.active_balance_sector);
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Pass* passes = passes_parse(data);
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Trip* trips = trips_parse(data);
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// print/append card data
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furi_string_cat_printf(parsed_data, "\e#CharlieCard");
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size_t uid_len = 0;
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const uint8_t* uid = mf_classic_get_uid(data, &uid_len);
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uint32_t card_number = bit_lib_bytes_to_num_be(uid, 4);
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furi_string_cat_printf(parsed_data, "\nSerial: 5-%lu", card_number);
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Money bal = money_parse(data, active_sector, 1, 5);
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furi_string_cat_printf(parsed_data, "\nBal: ");
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money_format_cat(parsed_data, bal);
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money_format_cat(parsed_data, balance_sector.balance);
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const uint16_t type = type_parse(data);
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furi_string_cat_printf(parsed_data, "\nType: ");
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type_format_cat(parsed_data, type);
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type_format_cat(parsed_data, balance_sector.type);
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Pass* passes = passes_parse(data);
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passes_format_cat(parsed_data, passes);
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free(passes);
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const uint16_t n_trips = n_uses(data, active_sec_enum);
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furi_string_cat_printf(parsed_data, "\nTrip Count: %u", n_trips);
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furi_string_cat_printf(parsed_data, "\nTrip Count: %u", counter_sector.n_uses);
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const DateTime iss = date_parse(data, active_sector, 0, 6);
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furi_string_cat_printf(parsed_data, "\nIssued: ");
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locale_format_dt_cat(parsed_data, &iss);
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locale_format_dt_cat(parsed_data, &balance_sector.issued);
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const DateTime e_v = main_end_validity_parse(data, active_sec_enum);
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furi_string_cat_printf(parsed_data, "\nExpiry: ");
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locale_format_dt_cat(parsed_data, &e_v);
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locale_format_dt_cat(parsed_data, &balance_sector.end_validity);
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DateTime last = date_parse(data, active_sector, 0, 1);
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furi_string_cat_printf(parsed_data, "\nExpired: %s", expired(e_v, last) ? "Yes" : "No");
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// const DateTime last = date_parse(data, active_sector, 0, 1);
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// furi_string_cat_printf(parsed_data, "\nExpired: %s", expired(e_v, last) ? "Yes" : "No");
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Trip* trips = trips_parse(data);
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trips_format_cat(parsed_data, trips);
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free(trips);
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