Re: [PATCH v5 BlueZ 4/4] Bluetooth: Handle Slave Connection Interval Range AD
From: Vinicius Costa Gomes
Date: Thu Apr 13 2017 - 14:24:51 EST
Hi Felipe,
"Felipe F. Tonello" <eu@xxxxxxxxxxxxxxxxx> writes:
> The Slave Connection Interval Range data type contains the Peripheral's
> preferred connection interval range, for all logical connections.
>
> It is useful to parse it in the Kernel so there is no multiple calls to
> MGMT interface to update the device connection parameters and subsequent
> connection command call to this device will use proper connection
> parameters. This saves context-switches and eliminates user-space to
> update the connection parameters each time a device is found or
> bluetoothd is restarted and so on. Also, there is no need for the
> user-space to know care about it because if the slave device wishes to
> persist with these parameters, it should use the L2CAP connection
> parameters upade request upon a completed connection.
nitpick: upade -> update
>
> Signed-off-by: Felipe F. Tonello <eu@xxxxxxxxxxxxxxxxx>
> ---
> net/bluetooth/mgmt.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 53 insertions(+)
>
> diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
> index 1fba2a03f8ae..ea5d6c85f173 100644
> --- a/net/bluetooth/mgmt.c
> +++ b/net/bluetooth/mgmt.c
> @@ -7442,6 +7442,46 @@ static bool is_filter_match(struct hci_dev *hdev, s8 rssi, u8 *eir,
> return true;
> }
>
> +static bool has_eir_slave_conn_int(const u8 *eir_data, u8 eir_len,
> + u16 *min_conn, u16 *max_conn)
> +{
> + u16 len = 0;
> + const u8 EIR_SLAVE_CONN_INT = 0x12; /* Slave Connection Interval Range */
> +
> + while (len < eir_len - 1) {
> + u8 field_len = eir_data[0];
> + const u8 *data;
> + u8 data_len;
> +
> + /* Check for the end of EIR */
> + if (field_len == 0)
> + break;
> +
> + len += field_len + 1;
> +
> + /* Do not continue EIR Data parsing if got
> + * incorrect length
> + */
> + if (len > eir_len)
> + break;
> +
> + data = &eir_data[2];
> + data_len = field_len - 1;
> +
> + if (eir_data[1] == EIR_SLAVE_CONN_INT) {
> + if (data_len < 4)
> + break;
> + *min_conn = le16_to_cpu(&data[0]);
> + *max_conn = le16_to_cpu(&data[2]);
> + return true;
> + }
> +
> + eir_data += field_len + 1;
> + }
> +
> + return false;
> +}
> +
> void mgmt_device_found(struct hci_dev *hdev, bdaddr_t *bdaddr, u8 link_type,
> u8 addr_type, u8 *dev_class, s8 rssi, u32 flags,
> u8 *eir, u16 eir_len, u8 *scan_rsp, u8 scan_rsp_len)
> @@ -7449,6 +7489,7 @@ void mgmt_device_found(struct hci_dev *hdev, bdaddr_t *bdaddr, u8 link_type,
> char buf[512];
> struct mgmt_ev_device_found *ev = (void *)buf;
> size_t ev_size;
> + struct hci_conn *hcon;
>
> /* Don't send events for a non-kernel initiated discovery. With
> * LE one exception is if we have pend_le_reports > 0 in which
> @@ -7521,6 +7562,18 @@ void mgmt_device_found(struct hci_dev *hdev, bdaddr_t *bdaddr, u8 link_type,
> ev->eir_len = cpu_to_le16(eir_len + scan_rsp_len);
> ev_size = sizeof(*ev) + eir_len + scan_rsp_len;
>
> + /* Search for Slave Connection Interval AD */
> + hcon = hci_conn_hash_lookup_le(hdev, bdaddr, addr_type);
> + if (hcon) {
> + u16 min_conn_int, max_conn_int;
> +
> + if (has_eir_slave_conn_int(ev->eir, ev->eir_len,
> + &min_conn_int, &max_conn_int)) {
> + hcon->le_conn_min_interval = min_conn_int;
> + hcon->le_conn_max_interval = max_conn_int;
> + }
> + }
> +
It's been some time that I looked at this code, so I could be missing
something, but I got the feeling that this part would make more sense if
it was at process_adv_report(), there's even the check for a pending
connection, so no need to redo that here.
Apart from this, the series looks good.
> mgmt_event(MGMT_EV_DEVICE_FOUND, hdev, ev, ev_size, NULL);
> }
>
> --
> 2.12.2
>
> --
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Cheers,
--
Vinicius