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-rw-r--r--elksmart-comm.c695
1 files changed, 695 insertions, 0 deletions
diff --git a/elksmart-comm.c b/elksmart-comm.c
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--- /dev/null
+++ b/elksmart-comm.c
@@ -0,0 +1,695 @@
+/*
+ * elksmart-comm.c: ELK Smart infrared dongle tool (for the 4th generation)
+ *
+ * Copyright (c) 2024, Přemysl Eric Janouch <p@janouch.name>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+ * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#include "config.h"
+#undef PROGRAM_NAME
+#define PROGRAM_NAME "elksmart-comm"
+#include "liberty/liberty.c"
+
+#include <libusb.h>
+
+// --- Utilities ---------------------------------------------------------------
+
+/// Search for a device with given vendor and product ID.
+/// This is quite similar to libusb_open_device_with_vid_pid().
+static libusb_device_handle *
+find_device (int vendor, int product, int *error)
+{
+ libusb_device **list = NULL;
+ libusb_device_handle *handle = NULL;
+ int result = 0;
+
+ ssize_t len = libusb_get_device_list (NULL, &list);
+ if (len < 0)
+ {
+ result = len;
+ goto out;
+ }
+
+ for (ssize_t i = 0; i < len; i++)
+ {
+ libusb_device *device = list[i];
+ struct libusb_device_descriptor desc = {};
+ if ((result = libusb_get_device_descriptor (device, &desc)))
+ print_debug ("%s", libusb_strerror (result));
+ else if (desc.idVendor != vendor || desc.idProduct != product)
+ continue;
+ else if (!(result = libusb_open (device, &handle)))
+ break;
+ }
+
+ libusb_free_device_list (list, true);
+out:
+ if (error != NULL && result != 0)
+ *error = result;
+ return handle;
+}
+
+static void
+wait_ms (long ms)
+{
+ struct timespec ts = { ms / 1000, (ms % 1000) * 1000 * 1000 };
+ nanosleep (&ts, NULL);
+}
+
+static void
+dump_hex (const unsigned char *buf, size_t len)
+{
+ for (size_t i = 0; i < len; i++)
+ printf ("%02x", buf[i]);
+ printf ("\n");
+}
+
+static bool
+read_hex (const char *string, struct str *out)
+{
+ static const char *alphabet = "0123456789abcdef";
+ str_reset (out);
+ while (true)
+ {
+ while (*string && strchr (" \t\n\r\v\f", *string))
+ string++;
+ if (!*string)
+ return true;
+
+ const char *hi, *lo;
+ if (!(hi = strchr (alphabet, tolower_ascii (*string++))) || !*string
+ || !(lo = strchr (alphabet, tolower_ascii (*string++))))
+ return false;
+
+ str_pack_u8 (out, (hi - alphabet) << 4 | (lo - alphabet));
+ }
+}
+
+// --- Coding ------------------------------------------------------------------
+
+// Values are in microseconds.
+struct pulse { unsigned on, off; };
+
+static bool
+pulse_equal (struct pulse a, struct pulse b)
+{
+ return a.on == b.on && a.off == b.off;
+}
+
+static size_t
+decode_learned_direct (const uint8_t *b, size_t b_len, struct pulse *pulses)
+{
+ size_t pulses_len = 0;
+ for (size_t i = 0; i < b_len; )
+ {
+ struct pulse *pulse = &pulses[pulses_len++];
+ while (b[i] == 0xff)
+ {
+ pulse->on += 4080;
+ if (++i == b_len)
+ return 0;
+ }
+ pulse->on += b[i++] * 16;
+
+ // Who cares, presumably it stays off.
+ if (i == b_len)
+ break;
+
+ while (b[i] == 0xff)
+ {
+ pulse->off += 4080;
+ if (++i == b_len)
+ return 0;
+ }
+ pulse->off += b[i++] * 16;
+ }
+ return pulses_len;
+}
+
+static struct pulse *
+decode_learned (const struct str *code, size_t *len, struct error **e)
+{
+ // This conveniently has an upper bound.
+ struct pulse *pulses = xcalloc (code->len, sizeof *pulses);
+ if (!(*len = decode_learned_direct
+ ((const uint8_t *) code->str, code->len, pulses)))
+ {
+ error_set (e, "code ends unexpectedly");
+ free (pulses);
+ return NULL;
+ }
+ return pulses;
+}
+
+static struct pulse *
+encode_nec_byte (struct pulse *p, uint8_t byte)
+{
+ for (int i = 7; i >= 0; i--)
+ *p++ = (struct pulse)
+ { .on = 550, .off = ((byte >> i) & 1) ? 1650 : 550 };
+ return p;
+}
+
+static struct pulse *
+encode_nec (const struct str *code, size_t *len, struct error **e)
+{
+ if (code->len % 2)
+ {
+ error_set (e, "NEC transmission format requires pairs");
+ return NULL;
+ }
+
+ // The timings seem to be rather tolerant.
+ *len = code->len / 2 * (1 /* leader */ + 32 + 1 /* stop */);
+ struct pulse *pulses = xcalloc (*len, sizeof *pulses), *p = pulses;
+ for (size_t i = 0; i < code->len; i += 2)
+ {
+ *p++ = (struct pulse) { .on = 8500, .off = 4250 };
+ p = encode_nec_byte (p, code->str[i + 0]);
+ p = encode_nec_byte (p, ~code->str[i + 0]);
+ p = encode_nec_byte (p, code->str[i + 1]);
+ p = encode_nec_byte (p, ~code->str[i + 1]);
+ *p++ = (struct pulse) { .on = 550, .off = 25000 };
+ }
+ return pulses;
+}
+
+static void
+compress_value (unsigned value, struct str *encoded)
+{
+ if (value <= 2032)
+ {
+ // We fix a minor problem in the original Ocrustar algorithm.
+ uint8_t v = value / 16. + .5;
+ str_pack_u8 (encoded, MAX (2, v));
+ }
+ else
+ do
+ {
+ uint8_t v = value & 0x7f;
+ if ((value >>= 7))
+ v |= 0x80;
+ str_pack_u8 (encoded, v);
+ } while (value);
+}
+
+static void
+compress_pulses (const struct pulse *pulses, size_t len, struct str *encoded)
+{
+ unsigned counts[len] = {};
+ for (size_t i = 0; i < len; i++)
+ for (size_t k = 0; k < len; k++)
+ if (pulse_equal (pulses[i], pulses[k]))
+ counts[i]++;
+
+ struct pulse p1 = {}, p2 = {};
+ size_t top1 = 0, top2 = 0;
+ for (size_t i = 0; i < len; i++)
+ if (counts[i] > counts[top1])
+ p1 = pulses[top1 = i];
+ for (size_t i = 0; i < len; i++)
+ if (counts[i] < counts[top1]
+ && counts[i] > counts[top2])
+ p2 = pulses[top2 = i];
+ else if (counts[top2] == counts[top1])
+ p2 = pulses[top2 = i];
+
+ // Although I haven't really tried it, something tells me that
+ // this will work even in the degenerated case of len <= 2.
+ // XXX: The receiver might not like multibyte values here,
+ // Ocrustar also oddly replaces 0xff with 0xfe for these fields.
+ compress_value (p2.on, encoded);
+ compress_value (p2.off, encoded);
+ compress_value (p1.on, encoded);
+ compress_value (p1.off, encoded);
+ str_pack_u8 (encoded, -1);
+ str_pack_u8 (encoded, -1);
+ str_pack_u8 (encoded, -1);
+
+ for (size_t i = 0; i < len; i++)
+ {
+ if (pulse_equal (pulses[i], p1))
+ str_pack_u8 (encoded, 0);
+ else if (pulse_equal (pulses[i], p2))
+ str_pack_u8 (encoded, 1);
+ else
+ {
+ compress_value (pulses[i].on, encoded);
+ compress_value (pulses[i].off, encoded);
+ }
+ }
+}
+
+// --- Device interaction ------------------------------------------------------
+
+enum
+{
+ USB_VENDOR_SMTCTL = 0x045c,
+
+ // 0x134 (EKX5S ~ 5s, 5th generation remote)
+ // 0x195 (EKX4S ~ 4s, 4th generation remote)
+ // 0x184 (international edition)
+ USB_PRODUCT_SMTCTL_SMART = 0x0195,
+
+ // There should only ever be one interface.
+ USB_INTERFACE = 0,
+};
+
+static uint8_t
+ c_transmit[] = { -1, -1, -1, -1 },
+ c_learn[] = { -2, -2, -2, -2 },
+ c_stop[] = { -3, -3, -3, -3 },
+ c_identify[] = { -4, -4, -4, -4 };
+
+static struct
+{
+ unsigned char endpoint_out; ///< Outgoing endpoint
+ unsigned char endpoint_in; ///< Incoming endpoint
+}
+g;
+
+static bool
+init_device_from_desc (struct libusb_config_descriptor *desc, struct error **e)
+{
+ // We're not being particuarly strict in here.
+ if (desc->bNumInterfaces != 1)
+ return error_set (e, "unexpected USB interface count");
+ if (desc->interface->num_altsetting != 1)
+ return error_set (e, "unexpected alternate setting count");
+
+ const struct libusb_interface_descriptor *asd = desc->interface->altsetting;
+ if (asd->bInterfaceClass != LIBUSB_CLASS_COMM)
+ return error_set (e, "unexpected USB interface class");
+ if (asd->bNumEndpoints != 2)
+ return error_set (e, "unexpected endpoint count");
+
+ bool have_out = false, have_in = false;
+ for (uint8_t i = 0; i < asd->bNumEndpoints; i++)
+ {
+ const struct libusb_endpoint_descriptor *epd = asd->endpoint + i;
+ if ((epd->bmAttributes & LIBUSB_TRANSFER_TYPE_MASK)
+ != LIBUSB_ENDPOINT_TRANSFER_TYPE_BULK)
+ return error_set (e, "unexpected endpoint transfer type");
+
+ switch ((epd->bEndpointAddress & LIBUSB_ENDPOINT_DIR_MASK))
+ {
+ break; case LIBUSB_ENDPOINT_OUT:
+ have_out = true;
+ g.endpoint_out = epd->bEndpointAddress;
+ break; case LIBUSB_ENDPOINT_IN:
+ have_in = true;
+ g.endpoint_in = epd->bEndpointAddress;
+ }
+ }
+ if (!have_out || !have_in)
+ return error_set (e, "USB interface is not bidirectional");
+ return true;
+}
+
+static bool
+init_device (libusb_device_handle *device, struct error **e)
+{
+ struct libusb_config_descriptor *desc = NULL;
+ int result =
+ libusb_get_active_config_descriptor (libusb_get_device (device), &desc);
+ if (result)
+ return error_set (e, "%s", libusb_strerror (result));
+
+ bool ok = true;
+ if ((result = libusb_kernel_driver_active (device, USB_INTERFACE)) == 1)
+ ok = error_set (e, "device is claimed by a kernel driver");
+ else if (result)
+ ok = error_set (e, "%s", libusb_strerror (result));
+ else
+ ok = init_device_from_desc (desc, e);
+
+ libusb_free_config_descriptor (desc);
+ return ok;
+}
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+
+static uint8_t
+mangle (uint8_t value)
+{
+ uint8_t reversed = 0;
+ for (int i = 0; i < 8; i++)
+ {
+ reversed = (reversed << 1) | (value & 1);
+ value >>= 1;
+ }
+ return ~reversed;
+}
+
+static uint8_t
+checksum (const uint8_t *b, size_t len)
+{
+ uint32_t sum = 0;
+ for (size_t i = 0; i < len; i++)
+ sum += b[i];
+ return mangle ((sum & 0xF0) | ((sum >> 8) & 0x0F));
+}
+
+static bool
+send_transmit (libusb_device_handle *device, unsigned long frequency,
+ const struct pulse *pulses, size_t pulses_len, struct error **e)
+{
+ if (g_debug_mode)
+ for (size_t i = 0; i < pulses_len; )
+ {
+ printf ("%u,%u", pulses[i].on, pulses[i].off);
+ putchar (++i == pulses_len ? '\n' : ',');
+ }
+
+ struct str compressed = str_make ();
+ compress_pulses (pulses, pulses_len, &compressed);
+
+ struct str message = str_make ();
+ str_append_data (&message, c_transmit, sizeof c_transmit);
+ frequency += 0x7ffff;
+ str_pack_u8 (&message, mangle (frequency >> 8));
+ str_pack_u8 (&message, mangle (frequency >> 16));
+ str_pack_u8 (&message, mangle (frequency));
+ str_pack_u8 (&message, mangle (compressed.len >> 8));
+ str_pack_u8 (&message, mangle (compressed.len));
+ str_append_str (&message, &compressed);
+ str_free (&compressed);
+
+ size_t i = 0;
+ uint8_t buffer[64];
+ bool ok = true;
+ while (i != message.len)
+ {
+ size_t chunk = MIN (62, message.len - i);
+ memcpy (buffer, message.str + i, chunk);
+ i += chunk;
+ if (chunk == 62)
+ {
+ buffer[chunk] = checksum (buffer, chunk);
+ chunk++;
+ }
+
+ int result = 0, len = 0;
+ if ((result = libusb_bulk_transfer (device, g.endpoint_out,
+ buffer, chunk, &len, 100)))
+ {
+ ok = error_set (e, "send: %s", libusb_strerror (result));
+ break;
+ }
+ wait_ms (2);
+ }
+ str_free (&message);
+ return ok;
+}
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+
+static bool
+pulse_is_likely_leader (const struct pulse *p)
+{
+ return p->on >= 2048 && p->off >= 2048;
+}
+
+static void
+try_to_depulse (const struct str *code)
+{
+ size_t len = 0;
+ struct pulse *pulses = decode_learned (code, &len, NULL);
+ if (!pulses)
+ return;
+
+ struct pulse *p = pulses, *end = p + len;
+ while (p != end && pulse_is_likely_leader (p))
+ {
+ p++;
+ printf ("Attempted pulse decode:\n");
+
+ uint8_t bits = 0, nibble = 0;
+ for (; p != end && !pulse_is_likely_leader (p); p++)
+ {
+ nibble = nibble << 1 | (p->off > 2 * p->on);
+ if (++bits == 4)
+ {
+ putchar ("0123456789abcdef"[nibble]);
+ bits = nibble = 0;
+ }
+ }
+ putchar ('\n');
+ }
+ free (pulses);
+}
+
+static bool
+recv_learn (libusb_device_handle *device, struct str *data, struct error **e)
+{
+ uint8_t buffer[64] = {};
+ int result = 0, len = 0;
+ while ((result = libusb_bulk_transfer (device, g.endpoint_in,
+ buffer, sizeof buffer, &len, 100)))
+ {
+ if (result != LIBUSB_ERROR_TIMEOUT)
+ return error_set (e, "learn/recv: %s", libusb_strerror (result));
+ print_debug ("learn/recv: %s", libusb_strerror (result));
+ }
+ if (len < 6 || memcmp (buffer, c_learn, sizeof c_learn))
+ return error_set (e, "learn/recv: %s", "unexpected response");
+
+ // This field might only make sense for a later device,
+ // because it doesn't always correspond with how much data we receive.
+ // Nonetheless, it does match exactly often enough.
+ size_t size = buffer[4] << 8 | buffer[5];
+ print_debug ("learn: code size: %zu", size);
+
+ str_append_data (data, buffer + 6, len - 6);
+ dump_hex ((const unsigned char *) data->str, data->len);
+ while (data->len < size)
+ {
+ if (!(result = libusb_bulk_transfer (device, g.endpoint_in,
+ buffer, sizeof buffer, &len, 100)))
+ {
+ dump_hex (buffer, len);
+
+ str_append_data (data, buffer, len);
+ print_debug ("learn: received %d (have %zu of %zu)",
+ len, data->len, size);
+ continue;
+ }
+ if (result != LIBUSB_ERROR_TIMEOUT)
+ return error_set (e, "learn/recv: %s", libusb_strerror (result));
+
+ // The device seems to queue up its output with pauses.
+ print_debug ("learn/recv: %s", libusb_strerror (result));
+ }
+
+ // As far as I know, this doesn't do anything,
+ // and the device doesn't accept it while scanning infrared codes either.
+ if ((result = libusb_bulk_transfer (device, g.endpoint_out,
+ c_stop, sizeof c_stop, &len, 100)))
+ return error_set (e, "learn/send: %s", libusb_strerror (result));
+ return true;
+}
+
+static bool
+send_learn (libusb_device_handle *device, struct error **e)
+{
+ int result = 0, len = 0;
+ if ((result = libusb_bulk_transfer (device, g.endpoint_out,
+ c_learn, sizeof c_learn, &len, 100)))
+ return error_set (e, "learn/send: %s", libusb_strerror (result));
+
+ printf ("Reading remote control codes.\n");
+ printf ("Press a remote control button from less than a centimeter.\n");
+ printf ("The dongle may be unusable until it returns some data.\n");
+ // ... Resetting the device using libusb_reset_device() doesn't help then.
+ printf ("If the code fails to replay, retry the capture.\n");
+
+ struct str data = str_make ();
+ bool ok = recv_learn (device, &data, e);
+ if (ok)
+ {
+ printf ("Full command:\n");
+ dump_hex ((const unsigned char *) data.str, data.len);
+ try_to_depulse (&data);
+ }
+
+ str_free (&data);
+ return ok;
+}
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+
+static bool
+send_identify (libusb_device_handle *device, struct error **e)
+{
+ uint8_t buffer[64] = {};
+ int result = 0, len = 0;
+ while (!(result = libusb_bulk_transfer (device, g.endpoint_in,
+ buffer, sizeof buffer, &len, 10)))
+ /* Flush buffers. */;
+
+ if ((result = libusb_bulk_transfer (device, g.endpoint_out,
+ c_identify, sizeof c_identify, &len, 100)))
+ return error_set (e, "identify/send: %s", libusb_strerror (result));
+ if ((result = libusb_bulk_transfer (device, g.endpoint_in,
+ buffer, sizeof buffer, &len, 100)))
+ return error_set (e, "identify/recv: %s", libusb_strerror (result));
+
+ // XXX: Sometimes, the device doesn't send any identification values.
+ if (len != 6 || memcmp (buffer, c_identify, sizeof c_identify)
+ || buffer[4] != 0x70 || buffer[5] != 0x01)
+ return error_set (e, "device busy or not supported");
+
+#if 0
+ // My device does not respond to this request.
+ static uint8_t c_serial[] = { -5, -5, -5, -5 };
+ if ((result = libusb_bulk_transfer (device, g.endpoint_out,
+ c_serial, sizeof c_serial, &len, 100)))
+ return error_set (e, "serial/send: %s", libusb_strerror (result));
+ if ((result = libusb_bulk_transfer (device, g.endpoint_in,
+ buffer, sizeof buffer, &len, 100)))
+ return error_set (e, "serial/recv: %s", libusb_strerror (result));
+ if (len < (int) sizeof c_serial
+ || memcmp (buffer, c_serial, sizeof c_serial))
+ return error_set (e, "serial retrieval failed");
+#endif
+ return true;
+}
+
+static bool
+run (libusb_device_handle *device, unsigned long frequency, bool nec,
+ char **codes, size_t codes_len, struct error **e)
+{
+ if (!send_identify (device, e))
+ return false;
+ if (!codes_len)
+ return send_learn (device, e);
+
+ struct str code = str_make ();
+ bool ok = true;
+ for (size_t i = 0; i < codes_len; i++)
+ {
+ if (!read_hex (codes[i], &code))
+ {
+ ok = error_set (e, "invalid hex string");
+ break;
+ }
+
+ size_t pulses_len = 0;
+ struct pulse *pulses = nec
+ ? encode_nec (&code, &pulses_len, e)
+ : decode_learned (&code, &pulses_len, e);
+
+ ok = pulses && send_transmit (device, frequency, pulses, pulses_len, e);
+ free (pulses);
+ if (!ok)
+ break;
+
+ wait_ms (100);
+ }
+ str_free (&code);
+ return ok;
+}
+
+// --- Main --------------------------------------------------------------------
+
+int
+main (int argc, char *argv[])
+{
+ unsigned long frequency = 38000;
+ bool nec = false;
+ static const struct opt opts[] =
+ {
+ { 'd', "debug", NULL, 0, "run in debug mode" },
+ { 'f', "frequency", "HZ", 0, "frequency (38000 Hz by default)" },
+ { 'n', "nec", NULL, 0, "use the NEC transmission format" },
+ { 'h', "help", NULL, 0, "display this help and exit" },
+ { 'V', "version", NULL, 0, "output version information and exit" },
+ { 0, NULL, NULL, 0, NULL }
+ };
+
+ struct opt_handler oh = opt_handler_make (argc, argv, opts, "[COMMAND...]",
+ "Transmit or receive infrared commands.");
+
+ int c;
+ while ((c = opt_handler_get (&oh)) != -1)
+ switch (c)
+ {
+ case 'd':
+ g_debug_mode = true;
+ break;
+ case 'f':
+ if (!xstrtoul (&frequency, optarg, 10) || !frequency)
+ exit_fatal ("invalid frequency");
+ break;
+ case 'n':
+ nec = true;
+ break;
+ case 'h':
+ opt_handler_usage (&oh, stdout);
+ exit (EXIT_SUCCESS);
+ case 'V':
+ printf (PROGRAM_NAME " " PROGRAM_VERSION "\n");
+ exit (EXIT_SUCCESS);
+ default:
+ print_error ("wrong options");
+ opt_handler_usage (&oh, stderr);
+ exit (EXIT_FAILURE);
+ }
+
+ argc -= optind;
+ argv += optind;
+
+ opt_handler_free (&oh);
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+
+#if LIBUSB_API_VERSION >= 0x0100010A
+ const struct libusb_init_option option =
+ {
+ .option = LIBUSB_OPTION_LOG_LEVEL,
+ .value.ival = LIBUSB_LOG_LEVEL_DEBUG,
+ };
+ int result = libusb_init_context (NULL, &option, g_debug_mode);
+#else
+ int result = libusb_init (NULL);
+#endif
+ if (result)
+ exit_fatal ("libusb: %s", libusb_strerror (result));
+
+ libusb_device_handle *device =
+ find_device (USB_VENDOR_SMTCTL, USB_PRODUCT_SMTCTL_SMART, &result);
+ if (result)
+ exit_fatal ("couldn't open device: %s", libusb_strerror (result));
+ else if (!device)
+ exit_fatal ("no suitable device found");
+
+ struct error *e = NULL;
+ if (!init_device (device, &e))
+ exit_fatal ("%s", e->message);
+ if ((result = libusb_claim_interface (device, USB_INTERFACE)) == 1)
+ exit_fatal ("couldn't claim interface: %s", libusb_strerror (result));
+
+ if (!run (device, frequency, nec, argv, argc, &e))
+ {
+ print_error ("%s", e->message);
+ error_free (e);
+ }
+
+ if ((result = libusb_release_interface (device, USB_INTERFACE)) == 1)
+ exit_fatal ("couldn't release interface: %s", libusb_strerror (result));
+
+ libusb_close (device);
+ libusb_exit (NULL);
+ return 0;
+}
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-09-21 07:28:59 +0000