Re: [PATCH BlueZ] gatt-database: Fix notifying on indicatable attr

[Curtis Maves <curtis@maves.io>]

Hi Luiz,
---- On Fri, 19 Feb 2021 19:55:06 -0500 Luiz Augusto von Dentz <luiz.dentz@gmail.com> wrote ----

 > 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 
 > 

This patch changes the if-statement around sending notifications to check that the
ccc->value is not indicating rather than checking if conf_cb (notify->conf) is null. 
This change makes unnecessary to conditionally pass the conf_cb. It's now simpler to always pass it.
--
Curtis Maves