testo: More robust probing and packet checking.
The CRC in every packet is now also checked. Thanks to Aurelien Jacobs for the CRC function.
This commit is contained in:
Bert Vermeulen
parent
6dcb97230e
commit
8789564070
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@ -320,6 +320,7 @@ static void receive_data(struct sr_dev_inst *sdi, unsigned char *data, int len)
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{
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struct dev_context *devc;
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int packet_size;
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uint16_t crc;
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devc = sdi->priv;
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@ -333,18 +334,30 @@ static void receive_data(struct sr_dev_inst *sdi, unsigned char *data, int len)
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memcpy(devc->reply + devc->reply_size, data, len);
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devc->reply_size += len;
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/* Sixth byte contains the length of the packet. */
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if (devc->reply_size >= 7) {
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if (devc->reply_size < 7)
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return;
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packet_size = 7 + devc->reply[6] * 7 + 2;
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if (devc->reply_size >= packet_size) {
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if (devc->reply_size < packet_size)
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return;
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if (!testo_check_packet_prefix(devc->reply, devc->reply_size))
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return;
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crc = crc16_mcrf4xx(0xffff, devc->reply, devc->reply_size - 2);
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if ((crc & 0xff) == devc->reply[devc->reply_size - 2]
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&& (crc >> 8) == devc->reply[devc->reply_size - 1]) {
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testo_receive_packet(sdi);
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devc->num_samples++;
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} else {
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sr_dbg("Packet has invalid CRC.");
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}
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devc->reply_size = 0;
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if (devc->limit_samples && devc->num_samples >= devc->limit_samples)
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dev_acquisition_stop(sdi, devc->cb_data);
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else
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testo_request_packet(sdi);
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}
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}
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}
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@ -51,6 +51,7 @@ SR_PRIV int testo_set_serial_params(struct sr_usb_dev_inst *usb)
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return SR_OK;
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}
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/* Due to the modular nature of the Testo hardware, you can't assume
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* which measurements the device will supply. Fetch a single result
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* set synchronously to see which measurements it has. */
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@ -66,13 +67,21 @@ SR_PRIV int testo_probe_channels(struct sr_dev_inst *sdi)
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devc = sdi->priv;
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usb = sdi->conn;
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sr_dbg("Probing for channels.");
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if (sdi->driver->dev_open(sdi) != SR_OK)
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return SR_ERR;
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if (testo_set_serial_params(usb) != SR_OK)
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return SR_ERR;
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/* Flush anything buffered from a previous run. */
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do {
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libusb_bulk_transfer(usb->devhdl, EP_IN, buf, MAX_REPLY_SIZE, &len, 10);
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} while (len > 2);
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if (libusb_bulk_transfer(usb->devhdl, EP_OUT, devc->model->request,
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devc->model->request_size, &devc->reply_size, 10) < 0)
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return SR_ERR;
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packet_len = 0;
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while(TRUE) {
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if (libusb_bulk_transfer(usb->devhdl, EP_IN, buf, MAX_REPLY_SIZE,
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@ -81,20 +90,26 @@ SR_PRIV int testo_probe_channels(struct sr_dev_inst *sdi)
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if (len == 2)
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/* FTDI cruft */
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continue;
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sr_dbg("got %d", len);
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if (packet_len + len - 2 > MAX_REPLY_SIZE)
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return SR_ERR;
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memcpy(packet + packet_len, buf + 2, len - 2);
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packet_len += len - 2;
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if (packet_len < 5)
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/* Not even enough to check prefix yet. */
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continue;
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if (!testo_check_packet_prefix(packet, packet_len)) {
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/* Tail end of some previous data, drop it. */
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packet_len = 0;
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continue;
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}
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if (packet_len >= 7) {
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if (!testo_check_packet(packet, packet_len))
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return SR_ERR;
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if (packet_len >= 7 + packet[6] * 7 + 2)
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/* Got a complete packet. */
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break;
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}
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}
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sdi->driver->dev_close(sdi);
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if (packet[6] > MAX_CHANNELS) {
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sr_err("Device says it has %d channels!", packet[6]);
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@ -125,8 +140,8 @@ SR_PRIV int testo_probe_channels(struct sr_dev_inst *sdi)
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sdi->channels = g_slist_append(sdi->channels, ch);
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}
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devc->num_channels = packet[6];
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sdi->driver->dev_close(sdi);
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sr_dbg("Found %d channel%s.", devc->num_channels,
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devc->num_channels > 1 ? "s" : "");
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return SR_OK;
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}
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@ -156,7 +171,7 @@ SR_PRIV int testo_request_packet(const struct sr_dev_inst *sdi)
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/* Check if the packet is well-formed. This matches packets for the
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* Testo 175/177/400/650/950/435/635/735/445/645/945/946/545. */
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SR_PRIV gboolean testo_check_packet(unsigned char *buf, int len)
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SR_PRIV gboolean testo_check_packet_prefix(unsigned char *buf, int len)
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{
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int i;
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unsigned char check[] = { 0x21, 0, 0, 0, 1 };
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@ -171,11 +186,29 @@ SR_PRIV gboolean testo_check_packet(unsigned char *buf, int len)
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}
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}
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/* TODO: check FCS, algorithm corresponds to python crcmod crc-16-mcrf4xx */
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return TRUE;
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}
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SR_PRIV uint16_t crc16_mcrf4xx(uint16_t crc, uint8_t *data, size_t len)
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{
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int i;
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if (!data || !len)
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return crc;
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while (len--) {
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crc ^= *data++;
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for (i = 0; i < 8; i++) {
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if (crc & 1)
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crc = (crc >> 1) ^ 0x8408;
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else
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crc = (crc >> 1);
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}
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}
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return crc;
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}
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static float binary32_le_to_float(unsigned char *buf)
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{
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GFloatIEEE754 f;
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@ -211,9 +244,6 @@ SR_PRIV void testo_receive_packet(const struct sr_dev_inst *sdi)
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g_string_free(dbg, TRUE);
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}
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if (!testo_check_packet(devc->reply, devc->reply_size))
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return;
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packet.type = SR_DF_ANALOG;
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packet.payload = &analog;
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analog.num_samples = 1;
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@ -223,7 +253,6 @@ SR_PRIV void testo_receive_packet(const struct sr_dev_inst *sdi)
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for (i = 0; i < devc->reply[6]; i++) {
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buf = devc->reply + 7 + i * 7;
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value = binary32_le_to_float(buf);
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sr_dbg("value: %f unit %d exp %d", value, buf[4], buf[6]);
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switch (buf[4]) {
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case 1:
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analog.mq = SR_MQ_TEMPERATURE;
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@ -242,7 +271,7 @@ SR_PRIV void testo_receive_packet(const struct sr_dev_inst *sdi)
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analog.unit = SR_UNIT_HECTOPASCAL;
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break;
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default:
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sr_dbg("Unsupported measurement unit %d", buf[4]);
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sr_dbg("Unsupported measurement unit %d.", buf[4]);
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return;
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}
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@ -257,7 +286,6 @@ SR_PRIV void testo_receive_packet(const struct sr_dev_inst *sdi)
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return;
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}
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ch = g_slist_nth_data(sdi->channels, i);
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sr_dbg("channel %d name %s unit %d", i, ch->name, analog.unit);
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analog.channels = g_slist_append(NULL, ch);
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sr_session_send(sdi, &packet);
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g_slist_free(analog.channels);
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@ -77,6 +77,7 @@ SR_PRIV int testo_set_serial_params(struct sr_usb_dev_inst *usb);
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SR_PRIV int testo_probe_channels(struct sr_dev_inst *sdi);
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SR_PRIV void receive_transfer(struct libusb_transfer *transfer);
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SR_PRIV int testo_request_packet(const struct sr_dev_inst *sdi);
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SR_PRIV gboolean testo_check_packet(unsigned char *buf, int len);
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SR_PRIV gboolean testo_check_packet_prefix(unsigned char *buf, int len);
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SR_PRIV uint16_t crc16_mcrf4xx(uint16_t crc, uint8_t *data, size_t len);
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SR_PRIV void testo_receive_packet(const struct sr_dev_inst *sdi);
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#endif
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