unleashed-firmware/applications/external/protoview/protocols/keeloq.c
2023-03-15 01:25:18 +03:00

121 lines
4.7 KiB
C

/* Copyright (C) 2022-2023 Salvatore Sanfilippo -- All Rights Reserved
* See the LICENSE file for information about the license.
*
* Microchip HCS200/HCS300/HSC301 KeeLoq, rolling code remotes.
*
* Usually 443.92 Mhz OOK, ~200us or ~400us pulse len, depending
* on the configuration.
*
* Preamble: 12 pairs of alternating pulse/gap.
* Sync: long gap of around 10 times the duration of the short-pulse.
* Data: pulse width encoded data. Each bit takes three cycles:
*
* 0 = 110
* 1 = 100
*
* There are a total of 66 bits transmitted.
* 0..31: 32 bits of encrypted rolling code.
* 32..59: Remote ID, 28 bits
* 60..63: Buttons pressed
* 64..64: Low battery if set
* 65..65: Always set to 1
*
* Bits in bytes are inverted: least significant bit is first.
* For some reason there is no checksum whatsoever, so we only decode
* if we find everything well formed.
*/
#include "../app.h"
static bool decode(uint8_t* bits, uint32_t numbytes, uint32_t numbits, ProtoViewMsgInfo* info) {
/* In the sync pattern, we require the 12 high/low pulses and at least
* half the gap we expect (5 pulses times, one is the final zero in the
* 24 symbols high/low sequence, then other 4). */
const char* sync_pattern = "101010101010101010101010"
"0000";
uint8_t sync_len = 24 + 4;
if(numbits - sync_len + sync_len < 3 * 66) return false;
uint32_t off = bitmap_seek_bits(bits, numbytes, 0, numbits, sync_pattern);
if(off == BITMAP_SEEK_NOT_FOUND) return false;
info->start_off = off;
off += sync_len; // Seek start of message.
/* Now there is half the gap left, but we allow from 3 to 7, instead of 5
* symbols of gap, to avoid missing the signal for a matter of wrong
* timing. */
uint8_t gap_len = 0;
while(gap_len <= 7 && bitmap_get(bits, numbytes, off + gap_len) == 0) gap_len++;
if(gap_len < 3 || gap_len > 7) return false;
off += gap_len;
FURI_LOG_E(TAG, "Keeloq preamble+sync found");
uint8_t raw[9] = {0};
uint32_t decoded = convert_from_line_code(
raw, sizeof(raw), bits, numbytes, off, "110", "100"); /* Pulse width modulation. */
FURI_LOG_E(TAG, "Keeloq decoded bits: %lu", decoded);
if(decoded < 66) return false; /* Require the full 66 bits. */
info->pulses_count = (off + 66 * 3) - info->start_off;
bitmap_reverse_bytes_bits(raw, sizeof(raw)); /* Keeloq is LSB first. */
int buttons = raw[7] >> 4;
int lowbat = (raw[8] & 0x1) == 0; // Actual bit meaning: good battery level
int alwaysone = (raw[8] & 0x2) != 0;
fieldset_add_bytes(info->fieldset, "encr", raw, 8);
raw[7] = raw[7] << 4; // Make ID bits contiguous
fieldset_add_bytes(info->fieldset, "id", raw + 4, 7); // 28 bits, 7 nibbles
fieldset_add_bin(info->fieldset, "s[2,1,0,3]", buttons, 4);
fieldset_add_bin(info->fieldset, "low battery", lowbat, 1);
fieldset_add_bin(info->fieldset, "always one", alwaysone, 1);
return true;
}
static void get_fields(ProtoViewFieldSet* fieldset) {
uint8_t remote_id[4] = {0xab, 0xcd, 0xef, 0xa0};
uint8_t encr[4] = {0xab, 0xab, 0xab, 0xab};
fieldset_add_bytes(fieldset, "encr", encr, 8);
fieldset_add_bytes(fieldset, "id", remote_id, 7);
fieldset_add_bin(fieldset, "s[2,1,0,3]", 2, 4);
fieldset_add_bin(fieldset, "low battery", 0, 1);
fieldset_add_bin(fieldset, "always one", 1, 1);
}
static void build_message(RawSamplesBuffer* samples, ProtoViewFieldSet* fieldset) {
uint32_t te = 380; // Short pulse duration in microseconds.
// Sync: 12 pairs of pulse/gap + 9 times gap
for(int j = 0; j < 12; j++) {
raw_samples_add(samples, true, te);
raw_samples_add(samples, false, te);
}
raw_samples_add(samples, false, te * 9);
// Data, 66 bits.
uint8_t data[9] = {0};
memcpy(data, fieldset->fields[0]->bytes, 4); // Encrypted part.
memcpy(data + 4, fieldset->fields[1]->bytes, 4); // ID.
data[7] = data[7] >> 4 | fieldset->fields[2]->uvalue << 4; // s[2,1,0,3]
int low_battery = fieldset->fields[3] != 0;
int always_one = fieldset->fields[4] != 0;
low_battery = !low_battery; // Bit real meaning is good battery level.
data[8] |= low_battery;
data[8] |= (always_one << 1);
bitmap_reverse_bytes_bits(data, sizeof(data)); /* Keeloq is LSB first. */
for(int j = 0; j < 66; j++) {
if(bitmap_get(data, 9, j)) {
raw_samples_add(samples, true, te);
raw_samples_add(samples, false, te * 2);
} else {
raw_samples_add(samples, true, te * 2);
raw_samples_add(samples, false, te);
}
}
}
ProtoViewDecoder KeeloqDecoder =
{.name = "Keeloq", .decode = decode, .get_fields = get_fields, .build_message = build_message};