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More cleanup, pass testing
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@zacharyweiss
zacharyweiss committed Apr 9, 2024
1 parent 3ea6d46 commit 33cfd63
Showing 1 changed file with 100 additions and 79 deletions.
179 changes: 100 additions & 79 deletions applications/main/nfc/plugins/supported_cards/charliecard.c
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Original file line number Diff line number Diff line change
Expand Up @@ -146,14 +146,14 @@ typedef struct {
uint16_t gate;
uint8_t g_flag;
Money fare;
uint8_t f_flag;
uint16_t f_flag;
} Trip;

typedef struct {
bool valid;
uint16_t type;
DateTime start;
DateTime end;
uint16_t pre;
uint16_t post;
DateTime date;
} Pass;

typedef struct {
Expand Down Expand Up @@ -682,20 +682,6 @@ static DateTime
return dt_delta(CHARLIE_EPOCH, ts_charlie * CHARLIE_TIME_DELTA_SECS);
}

static uint16_t type_parse(const MfClassicData* data) {
/* Card type data stored in the first 10bits of block 1 of sectors 2 & 3 (Block 9 & Block 13, from card start)
To my knowledge, card type should never change, so we can check either
without caring which is active. For my sanity, I check both, and assert equal.
*/

// bitshift (2bytes = 16 bits) by 6bits for just first 10bits
const uint16_t type1 = pos_to_num(data, 2, 1, 0, 2) >> 6;
const uint16_t type2 = pos_to_num(data, 3, 1, 0, 2) >> 6;
furi_assert(type1 == type2);

return type1;
}

static DateTime end_validity_parse(
const MfClassicData* data,
uint8_t sector_num,
Expand All @@ -716,36 +702,45 @@ static Pass
// Sub-byte field divisions not drawn to scale, see code for exact bit offsets
//
// 0 1 2 3 4 5
// +----.----.----+----.----.----+
// | type | end | start |
// +----.----.----+----.----.----+
// +----.----.----.----+----.----+
// | uk1 | date | uk2 |
// +----.----.----.----+----.----+
//
// "Blank" entries are as follows:
// 0 1 2 3 4 5
// +----.----.----.----.----.--+-.
// | 00 20 00 00 00 0|
// +----.----.----.----.----.--+-.

// +----.----.----.----.----.----+
// | 00 20 00 00 00 00 |
// +----.----.----.----.----.----+
//
// if not blank, uk1 MSB seems to always be set to 1...
// the sole bit set to 1 on the blank entry seems to divide
// the uk1 and date fields, and is always set to 1 regardless
// same is true of type & end-validity split found in balance sector
//
//
// check for empty, if so, return struct filled w/ 0s
// (incl "valid" field: hence, "valid" is false-y)
if(pos_to_num(data, sector_num, block_num, byte_num, 6) == 0x002000000000) {
return (Pass){0};
}

DateTime start = date_parse(data, sector_num, block_num, byte_num + 1);
uint16_t type = pos_to_num(data, sector_num, block_num, byte_num, 2) >> 6;
// const DateTime start = date_parse(data, sector_num, block_num, byte_num + 1);

const uint16_t pre = pos_to_num(data, sector_num, block_num, byte_num, 2) >> 6;
const uint16_t post = pos_to_num(data, sector_num, block_num, byte_num + 4, 2);

// these values make sense for end
DateTime end = end_validity_parse(data, sector_num, block_num, byte_num + 1);
// these values make sense for a date, but implied position of type
// before end validity, as seen in balance sector, doesn't seem
// to produce sensible values
const DateTime date = end_validity_parse(data, sector_num, block_num, byte_num + 1);

// DateTime start = date_parse(data, sector_num, block_num, byte_num);
// uint16_t type = 0; // pos_to_num(data, sector_num, block_num, byte_num + 3, 2) >> 6;

return (Pass){true, type, start, end};
return (Pass){true, pre, post, date};
}

static Trip
trip_parse(const MfClassicData* data, uint8_t sector_num, uint8_t block_num, uint8_t byte_num) {
static Trip trip_parse(const MfClassicData* data, uint8_t sector, uint8_t block, uint8_t byte) {
/* This function parses individual trips. Each trip packs 7 bytes, stored as follows:
0 1 2 3 4 5 6
Expand All @@ -757,19 +752,23 @@ static Trip
Amount appears to contain some flag bits, however, it is unclear what precisely their function is.
Gate ID ("loc") is only the first 13 bits of 0x3:0x5, the final three bits appear to be flags ("f").
Least significant flag bit (ie "loc & 0x1") seems to indicate:
— When 0, fare (the amount by which balance is decremented)
— When 1, refill (the amount by which balance is incremented)
On monthly pass cards, MSB of amt will be set: 0x8000 (negative zero)
Seemingly randomly (irrespective of card type, last trip, etc) 0x0001 will be set on amt in addition to
whatever the regular fare is (a half cent more). I am uncertain what this flag indicates.
Least significant flag bit seems to indicate:
— When f & 1 == 0, fare (the amount by which balance is decremented)
— When f & 1 == 1, refill (the amount by which balance is incremented)
MSB (sign bit) of amt seems to serve the same role, just inverted, ie
— When amt & 0x8000 == 0x8000, fare
— When amt & 0x8000 == 0, refill
Remaining unknown bits:
— f & 0b100
— f & 0b010
— amt & 1; does not seem to correspond with card type, last trip, first trip, refill v. fare, etc
*/
const DateTime date = date_parse(data, sector_num, block_num, byte_num);
const uint16_t gate = pos_to_num(data, sector_num, block_num, byte_num + 3, 2) >> 3;
const uint8_t g_flag = pos_to_num(data, sector_num, block_num, byte_num + 3, 2) & 0b111;
const Money fare = money_parse(data, sector_num, block_num, byte_num + 5);
const uint8_t f_flag = pos_to_num(data, sector_num, block_num, byte_num + 5, 2) & 0x8001;
const DateTime date = date_parse(data, sector, block, byte);
const uint16_t gate = pos_to_num(data, sector, block, byte + 3, 2) >> 3;
const uint8_t g_flag = pos_to_num(data, sector, block, byte + 3, 2) & 0b111;
const Money fare = money_parse(data, sector, block, byte + 5);
const uint16_t f_flag = pos_to_num(data, sector, block, byte + 5, 2) & 0x8001;
return (Trip){date, gate, g_flag, fare, f_flag};
}

Expand All @@ -782,12 +781,15 @@ static uint32_t mfg_sector_parse(const MfClassicData* data) {
//
// 0 1 2 3 4 5 6 7 8 9 A B C D E F
// +----.----.----.----+----+----.----.----.----+----+----.----.----.----.----+----+
// 0x000 | UID |LRC | 88 04 00 C8 |unkn| 00 20 00 00 00 |unkn|
// 0x000 | UID | rc | 88 04 00 C8 | uk | 00 20 00 00 00 | uk |
// +----.----.----.----+----+----.----.----.----+----+----.----.----.----.----+----+
// 0x010 | 4E 0F 04 10 04 10 04 10 04 10 04 10 04 10 04 10 |
// +----.----.----.----.----.----.----.----.----.----.----.----.----.----.----.----+
// 0x020 | ... 00 00 ... |
// +----.----.----.----.----.----.----.----.----.----.----.----.----.----.----.----+
//
// rc := "redundancy check" (lrc / bcc)
// uk := "unknown"

size_t uid_len = 0;
const uint8_t* uid = mf_classic_get_uid(data, &uid_len);
Expand All @@ -800,13 +802,16 @@ static CounterSector counter_sector_parse(const MfClassicData* data) {
// Trip/transaction counters (Sector 1)
//
// 0 1 2 3 4 5 6 7 8 9 A B C D E F
// +----.----.----.----.----.----.----.----.----.----.----.----.----.----.----+----+
// +----.----.----.----.----.----.----.----.----.----.----.----.----.----.----.----+
// 0x040 | 04 10 23 45 66 77 ... 00 00 ... |
// +----.----+----+----.----.----.----.----.----.----.----.----.----.----.----+----+
// 0x050 | uses1 |unkn| ... 00 00 ... |
// +----.----+----+----.----.----.----.----.----.----.----.----.----.----.----.----+
// 0x060 | uses2 |unkn| ... 00 00 ... |
// 0x050 | uses1 | uk | ... 00 00 ... |
// +----.----+----+----.----.----.----.----.----.----.----.----.----.----.----.----+
// 0x060 | uses2 | uk | ... 00 00 ... |
// +----.----+----+----.----.----.----.----.----.----.----.----.----.----.----.----+
//
// uk := "unknown"; if nonzero, seems to only occupy the first 4 bits (ie, mask w/ 0xF0),
// with the remaining 4 zero

// Card has two transaction sectors (2 & 3) containing balance data, with two
// corresponding trip counters in 0x50:0x51 & 0x60:0x61 (sector 1, byte 0:1 of blocks 1 & 2).
Expand All @@ -827,27 +832,30 @@ static CounterSector counter_sector_parse(const MfClassicData* data) {
}

static BalanceSector balance_sector_parse(const MfClassicData* data, uint8_t active_sector) {
// Balance / type / last transaction (Sector 2 or 3)
// Balance & misc card info (Sector 2 or 3)
//
// 0 1 2 3 4 5 6 7 8 9 A B C D E F
// +----+----.----.----+----.----+----.----.----+----.----+----.----+----+----.----+
// 0x080 | 11 | date last | loc last| date issued | 65 00 | unknown | 00 | crc | 0x0C0
// +----+----.----.----+----+----+----+----+----+----.----+----.----+----+----.----+
// 0x090 | type |end validity|unkn| balance | 00 | unknown | crc | 0x0D0
// 0x090 | type |end validity| uk | balance | 00 | unknown | crc | 0x0D0
// +----.----.----.----+----+----.----+----+----.----.----.----.----.----+----.----+
// 0x0A0 | 20 ... 00 00 ... 04 | crc | 0x0E0
// +----.----.----.----.----.----.----.----.----.----.----.----.----.----+----.----+
//
// "Active" balance sector alternates between 2 and 3
// Last trip/transaction info in balance sector (date last & loc last)
// also included in transaction log, hence don't bother to read here
// Last trip/transaction info in balance sector ("date last" & "loc last")
// is also included in transaction log, hence don't bother to read here
//
// Inactive balance sector represent the transaction N-1 balance data
// Inactive balance sector represent the transaction N-1 version
// (where active sector represents data from transaction N).

const DateTime issued = date_parse(data, active_sector, 0, 6);
const DateTime end_validity = end_validity_parse(data, active_sector, 1, 1);
const uint16_t type = type_parse(data);
// Card type data stored in the first 10bits of block 1
// (0x90 or 0xD0 depending on active sector)
// bitshift (2bytes = 16 bits) by 6bits for just first 10bits
const uint16_t type = pos_to_num(data, active_sector, 1, 0, 2) >> 6;
const Money bal = money_parse(data, active_sector, 1, 5);

return (BalanceSector){bal, type, issued, end_validity};
Expand All @@ -857,16 +865,17 @@ static Pass* passes_parse(const MfClassicData* data) {
// Passes, speculative (Sectors 4 &/or 5)
//
// 0 1 2 3 4 5 6 7 8 9 A B C D E F
// +----.----.----.----.----.-+--.----+----.----.----.----.----.-+--.----+----.----+
// 0x100 | pass0? |0 00 | pass1? |0 00 | crc | 0x140
// +----.----.----.----.----.-+--.----+----.----.----.----.----.-+--.----+----.----+
// +----.----.----.----.----.----+----+----.----.----.----.----.----+----+----.----+
// 0x100 | pass0? | 00 | pass1? | 00 | crc | 0x140
// +----.----.----.----.----.----+----+----.----.----.----.----.----+----+----.----+
// 0x110 | ... 00 00 ... | crc | 0x150
// +----.----.----.----.----.----.----.----.----.----.----.----.----.----+----.----+
// 0x120 | ... 00 ... 05 | crc | 0x160
// +----.----.----.----.----.----.----.----.----.----.----.----.----.----+----.----+
//
// WIP. Read in all speculative passes into array
// 4 separate fields? active vs inactive sector for 2 passes?
// something else entirely?

Pass* passes = malloc(sizeof(Pass) * CHARLIE_N_PASSES);

Expand Down Expand Up @@ -1009,23 +1018,35 @@ void type_format_cat(FuriString* out, uint16_t type) {
}

void pass_format_cat(FuriString* out, Pass pass) {
furi_string_cat_printf(out, "\n-Type: ");
type_format_cat(out, pass.type);
furi_string_cat_printf(out, "\n-Start: ");
locale_format_dt_cat(out, &pass.start);
furi_string_cat_printf(out, "\n-End: ");
locale_format_dt_cat(out, &pass.end);
furi_string_cat_printf(out, "\n-Pre: %b", pass.pre);
// type_format_cat(out, pass.type);
furi_string_cat_printf(out, "\n-Post: %b", pass.post);
// locale_format_dt_cat(out, &pass.start);
furi_string_cat_printf(out, "\n-Date: ");
locale_format_dt_cat(out, &pass.date);
}

void passes_format_cat(FuriString* out, Pass* passes) {
if(is_debug()) {
furi_string_cat_printf(out, "\nPasses (DEBUG / WIP):");
for(size_t i = 0; i < CHARLIE_N_PASSES; i++) {
if(passes[i].valid) {
furi_string_cat_printf(out, "\nPass %u", i + 1);
pass_format_cat(out, passes[i]);
furi_string_cat_printf(out, "\n");
}
// only print passes if DEBUG on
if(!is_debug()) {
return;
}

// only print if there is at least 1 valid pass to print
bool any_valid = false;
for(size_t i = 0; i < CHARLIE_N_PASSES; i++) {
any_valid |= passes[i].valid;
}
if(!any_valid) {
return;
}

furi_string_cat_printf(out, "\nPasses (DEBUG / WIP):");
for(size_t i = 0; i < CHARLIE_N_PASSES; i++) {
if(passes[i].valid) {
furi_string_cat_printf(out, "\nPass %u", i + 1);
pass_format_cat(out, passes[i]);
furi_string_cat_printf(out, "\n");
}
}
}
Expand All @@ -1044,19 +1065,19 @@ void trip_format_cat(FuriString* out, Trip trip) {
if(!!(trip.g_flag & 0x1) && (trip.fare.dollars == FARE_BUS.dollars) &&
(trip.fare.cents == FARE_BUS.cents)) {
// if not a refill, and the fare amount is equal to bus fare (any better approach? flag bits for modality?)
// format for bus (gate ID on busses = posted bus #)
furi_string_cat_printf(out, "%sBus#%u", sep, trip.gate);
// format for bus — supposedly some correlation between gate ID & bus #, haven't investigated
furi_string_cat_printf(out, "%s#%u", sep, trip.gate);
} else if(get_map_item(trip.gate, charliecard_fare_gate_ids, kNumFareGateIds, &sta)) {
// station found in fare gate ID map, append station name
furi_string_cat_str(out, sep);
furi_string_cat_str(out, sta);
} else {
// no found station in fare gate ID map & not a bus, just print ID w/o add'l info
furi_string_cat_printf(out, "%s%u", sep, trip.gate);
furi_string_cat_printf(out, "%s#%u", sep, trip.gate);
}
// print flags for debugging purposes
if(is_debug()) {
furi_string_cat_printf(out, "%s%u%s%u", sep, trip.g_flag, sep, trip.f_flag);
furi_string_cat_printf(out, "%s%x%s%x", sep, trip.g_flag, sep, trip.f_flag);
}
}

Expand Down Expand Up @@ -1117,9 +1138,6 @@ static bool charliecard_parse(const NfcDevice* device, FuriString* parsed_data)
furi_string_cat_printf(parsed_data, "\nType: ");
type_format_cat(parsed_data, balance_sector.type);

passes_format_cat(parsed_data, passes);
free(passes);

furi_string_cat_printf(parsed_data, "\nTrip Count: %u", counter_sector.n_uses);

furi_string_cat_printf(parsed_data, "\nIssued: ");
Expand All @@ -1131,6 +1149,9 @@ static bool charliecard_parse(const NfcDevice* device, FuriString* parsed_data)
// const DateTime last = date_parse(data, active_sector, 0, 1);
// furi_string_cat_printf(parsed_data, "\nExpired: %s", expired(e_v, last) ? "Yes" : "No");

passes_format_cat(parsed_data, passes);
free(passes);

trips_format_cat(parsed_data, trips);
free(trips);

Expand Down

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