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References: <20210219174946.599144-1-curtis@maves.io>
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From:   Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Date:   Fri, 19 Feb 2021 16:55:06 -0800
Message-ID: <CABBYNZKakfpzTOdZaoa0tZ5Umqu9MKMmkMfNN51XY5owC_KWwQ@mail.gmail.com>
Subject: Re: [PATCH BlueZ] gatt-database: Fix notifying on indicatable attr
To:     Curtis <curtis@maves.io>
Cc:     "linux-bluetooth@vger.kernel.org" <linux-bluetooth@vger.kernel.org>
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Precedence: bulk

Hi Curtis,

On Fri, Feb 19, 2021 at 10:11 AM Curtis <curtis@maves.io> wrote:
>
> When a local GATT characteristic has both the indicate and notify
> properties, notifications will not be send to clients requesting them.
> This change fixes this, allowing for notifications to be sent.
>
> Also simplifies logic about when notifications/indications should
> be sent.
> ---
>  src/gatt-database.c | 15 ++++++---------
>  1 file changed, 6 insertions(+), 9 deletions(-)
>
> diff --git a/src/gatt-database.c b/src/gatt-database.c
> index d635c3214..bd5864bcd 100644
> --- a/src/gatt-database.c
> +++ b/src/gatt-database.c
> @@ -1344,10 +1344,7 @@ static void send_notification_to_device(void *data, void *user_data)
>         }
>
>         ccc = find_ccc_state(device_state, notify->ccc_handle);
> -       if (!ccc)
> -               return;
> -
> -       if (!ccc->value || (notify->conf && !(ccc->value & 0x0002)))
> +       if (!ccc || !(ccc->value & 0x0003))
>                 return;
>
>         device = btd_adapter_find_device(notify->database->adapter,
> @@ -1374,7 +1371,7 @@ static void send_notification_to_device(void *data, void *user_data)
>          * TODO: If the device is not connected but bonded, send the
>          * notification/indication when it becomes connected.
>          */
> -       if (!notify->conf) {
> +       if (!(ccc->value & 0x0002)) {
>                 DBG("GATT server sending notification");
>                 bt_gatt_server_send_notification(server,
>                                         notify->handle, notify->value,
> @@ -2415,8 +2412,8 @@ static bool sock_io_read(struct io *io, void *user_data)
>                                 gatt_db_attribute_get_handle(chrc->attrib),
>                                 buf, bytes_read,
>                                 gatt_db_attribute_get_handle(chrc->ccc),
> -                               chrc->props & BT_GATT_CHRC_PROP_INDICATE ?
> -                               conf_cb : NULL, chrc->proxy);
> +                               conf_cb,
> +                               chrc->proxy);

Not why are you changing this code to always set the conf_cb? This
would then always send indication rather then notifications:

https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/src/gatt-database.c#n1387

We might need to check what value it stored in the ccc state if both
indication and notification is supported.

>
>         return true;
>  }
> @@ -2725,8 +2722,8 @@ static void property_changed_cb(GDBusProxy *proxy, const char *name,
>                                 gatt_db_attribute_get_handle(chrc->attrib),
>                                 value, len,
>                                 gatt_db_attribute_get_handle(chrc->ccc),
> -                               chrc->props & BT_GATT_CHRC_PROP_INDICATE ?
> -                               conf_cb : NULL, proxy);
> +                               conf_cb,
> +                               proxy);
>  }
>
>  static bool database_add_ccc(struct external_service *service,
> --
> 2.30.1
>
>


-- 
Luiz Augusto von Dentz