bluez/TODO

Background
==========

- Priority scale: High, Medium and Low

- Complexity scale: C1, C2, C4 and C8.  The complexity scale is exponential,
  with complexity 1 being the lowest complexity.  Complexity is a function
  of both task 'complexity' and task 'scope'.

  The general rule of thumb is that a complexity 1 task should take 1-2 weeks
  for a person very familiar with BlueZ codebase.  Higher complexity tasks
  require more time and have higher uncertainty.

  Higher complexity tasks should be refined into several lower complexity tasks
  once the task is better understood.

General
==========

- UUID handling: Use the new functions created for UUID handling in all parts
  of BlueZ code.  Currently, the new bt_uuid_* functions are being used by
  GATT-related code only.

  Priority: high
  Complexity: C4

- Rename glib-helper file to a more convenient name. The idea is try to keep
  only sdp helpers functions. bt_* prefix shall be also changed.

  Priority: Low
  Complexity: C1

- Function in src/adapter.c to convert old storage files to new ini-file format
  should be removed 6-8 months after first BlueZ 5 release.

  Priority: Low
  Complexity: C1

- Remove usage of symlinks for drivers, such as profiles/input/suspend.c and
  profiles/sap/sap.c. Instead, select drivers at runtime by using config
  options or probing for running D-Bus services (using e.g.
  g_dbus_add_service_watch()). Idea first mentioned on
  http://thread.gmane.org/gmane.linux.bluez.kernel/30175/focus=30190.

- Reuse connection handling code of src/profile.c also for built-in profiles
  so plugins would only need to register their btd_profile and the core takes
  care of the rest including listen to the right channel and manages the sdp
  record. Once btd_profile manages the connection it can also notify about
  their state, this probably remove the need of having callbacks to
  .connect/.disconnect since their state can be tracked, it also enables any
  plugin to track any profile state change which can be useful for e.g.
  a connection policy plugin in case one is needed.

  Priority: Low
  Complexity: C2

BlueZ 5
=======

Priority/Complexity omitted as all items are required before 5.0 is
released.

- Fix all btd_profile instances to only have one UUID in remote_uuids,
  then convert remote_uuids to a single remote_uuid.

- Once the above item is done switch ConnectProfile to match remote_uuid
  instead of local_uuid (as that's more intuitive).

- Convert obexd & obex-client to ObjectManager/Properties

- Don't install libbluetooth by default (put it behind a configure switch)

- [pending] Switch plugins to standard D-Bus properties interface

- [pending] Add connect/disconnect callbacks to all btd_profile
  instances that need them and add auto_connect = true to the ones that
  make sense.

- [pending] Convert storage to user per-remote device directories and
  ini-file format

Completed items:

- Remove powered state storing and rely on external entity to do the
  power on/off.

- Remove Adapter.Request/ReleaseSession and Agent.ConfirmModeChange.
  Remove usage from obex-client.

- Remove Device.DiscoverServices & Device.CancelDiscovery

- Convert obexd to use org.bluez.Profile

- Remove org.bluez.Service interface (it has become unnecessary thanks
  to org.bluez.Profile). obexd needs to be converted to use the new
  interface first.

- Auto-connect newly registered profiles if we're in a connected state
  created by Device.Connect. This will fix e.g. oFono crashing and
  restarting.

- Update Device.Connect to connect any "auto_connect" profiles that are
  not currently connected instead of returning "already connected".

- Update the btd_profile connection state tracking so that device.c also
  knows about remotely initiated connections.

- Remove deprecated D-Bus signals, methods and properties
  (ensuring new ones are in place to replace what's removed).

- Merge obexd.git into bluez.git

- Add Agent callback for incoming just-works (RequestAuthorization)

- Switch to standard object manager interface

- Switch core to standard D-Bus properties interface

- Remove telephony driver framework

- Move base path to /org/bluez

- Remove GStreamer and libsbc code

- Reorganize source tree according to RFC sent to linux-bluetooth
  (Subject: [RFC] Reorganizing the BlueZ source tree)

- Make mgmtops part of Bluetooth core. mgmt will be the only way to
  communicate with the kernel in BlueZ so a plugin is not needed
  anymore. Probably plugins/mgmtops.c -> src/mgmt.c

- Remove UNIX socket based audio interface (along with ALSA plugin)

- Remove unmaintained plugins like pnat and maemo6

- Remove CreateDevice/CreatePairedDevice and use D-Bus objects for
  discovered devices. This fixes the issue of not exposing the address
  type in DeviceFound and the Create* method calls

Low Energy
==========

- Advertising management. Adapter interface needs to be changed to manage
  connection modes, adapter type and advertising policy. See Volume 3,
  Part C, section 9.3. If Attribute Server is enabled the LE capable
  adapter shall to start advertising. Further investigation is necessary
  to define which connectable mode needs to be supported: Non-connectable,
  directed connectable and undirected connectable. Basically, two connectable
  scenarios shall be addressed:
  1. GATT client is disconnected, but intends to become a Peripheral to
     receive indications/notifications.
  2. GATT server intends to accept connections.

  Priority: Medium
  Complexity: C2

- Define Auto Connection Establishment Procedure. Some profiles such as
  Proximity requires an active link to identify path lost situation. It is
  necessary to define how to manage connections, it seems that White List
  is appropriated to address auto connections, however is not clear if the
  this procedure shall be a profile specific detail or if the remote device
  object can expose a property "WhiteList", maybe "Trusted" property can be
  also used for this purpose. Another alternative is to define a method to
  allow application to request/register the wanted scanning/connection
  parameters. Before start this task, a RFC/PATCH shall be sent to the ML.
  See Volume 3, Part C, section 9.3.5 for more information.

  Priority: Medium
  Complexity: C2

- Implement a tool(or extend hciconfig) to setup the advertising parameters
  and data. Extend hciconfig passing extra arguments when enabling the
  advertises is not the right approach, it will be almost impossible to
  address all arguments needed in an acceptable way. For testing, we need
  a tool to change easily the AD Flags, the UUIDs and other data that can be
  exported through the advertising data field. Suggestions: 1) extend hciconfig
  passing a config file when enabling advertises; 2) write a ncurses based tool

  Priority: Medium
  Complexity: C2

- Add new property in the DeviceFound signal to report the device type:
  BR/EDR, single mode or dual-mode.

  Priority: Medium
  Complexity: C1

- Privacy: When privacy is enabled in the adapter, LE scanning/connection
  should use a private address. StartDiscovery method shall be changed and
  new adapter property shall be added.

  Priority: Medium
  Complexity: C1

- Static random address setup and storage. Once this address is written
  in a given remote, the address can not be changed anymore.

  Priority: Low
  Complexity: C1

- Reconnection address: Reconnection address is a non resolvable private
  address that the central writes in the peripheral. BlueZ will support
  multiple profiles, it is not clear how it needs to be implemented.
  Further discussion is necessary.

  Priority: Low
  Complexity: C2

- Device Name Characteristic is a GAP characteristic for Low Energy. This
  characteristic shall be integrated/used in the discovery procedure. The
  idea is to report the value of this characteristic using DeviceFound signals.
  Discussion with the community is needed before to start this task. Other GAP
  characteristics for LE needs to follow a similar approach. It is not clear
  if all GAP characteristics can be exposed using properties instead of a primary
  service characteristics.
  See Volume 3, Part C, section 12.1 for more information.

  Priority: Low
  Complexity: C2

ATT/GATT
========

- At the moment authentication and authorization is not supported at the
  same time, read/write requirements in the attribute server needs to
  be extended. According to Bluetooth Specification a server shall check
  authentication and authorization requirements before any other check is
  performed.

  Priority: Medium
  Complexity: C1

- ATT/GATT parsing to hcidump. Partially implemented, missing to fix
  multiple advertises in the same event and RSSI.

  Priority: Medium
  Complexity: C2

- Implement ATT PDU validation. Malformed PDUs can cause division by zero
  when decoding PDUs. A proper error PDU should be returned for this case.
  See decoding function in att.c file.

  Priority: Medium
  Complexity: C1

- Fix hard-coded PSM for GATT services over basic rate.

  Priority: Low
  Complexity: C1

- Refactor read_by_group() and read_by_type() in src/attrib-server.c
  (they've grown simply too big). First step could be to move out the
  long for-loops to new functions called e.g. get_groups() and get_types().

  Priority: Low
  Complexity: C1

- Agent for characteristics: Agent interface should be extended to support
  authorization per characteristic if the remote is not in the trusted list.

  Priority: Low
  Complexity: C1

- gatttool should have the ability to wait for req responses before
  quitting (some servers require a small sleep even with cmd's). Maybe a
  --delay-exit or --timeout command line switch.

  Priority: Low
  Complexity: C1

- Refactoring of gatt.c functions. Currently, the callbacks of the services
  and characteristics discovery functions return the ATT PDU and the caller
  needs to call again the same function to fetch the remaining data when
  necessary. Investigate if all results can be returned in the callback
  result to avoid repeated code. Before change the code, please analyze
  if this change will not break the GATT/ATT qualification tests. Maybe
  an interactive fetch/query is necessary to pass the tests.

  Priority: Low
  Complexity: C1

- Client needs to export a property in the Device Characteristic hierarchy
  to manage characteristic value changes reports in the remote device.
  Currently, Client Characteristic Configuration attribute is not exposed
  as an object. The user needs to use gatttool to change the value of the
  this attribute to receive notification/indications. Export this attribute
  as a property is a proposal that needs further discussion.

  Priority: Low
  Complexity: C1

- Attribute server should process queued GATT/ATT commands if the
  client disconnects. The client can simply send a command and quit,
  without wait for a response(ex: Write Command). For this scenario
  that the client disconnects the link quickly the queued received
  command is ignored.

  Priority: Low
  Complecity: C1

- Add sdp discovery support to gatttool with BR (--sdp, default is 0x1f)

  Priority: Low
  Complexity: C1

- Implement Server characteristic Configuration support in the attribute
  server to manage characteristic value broadcasting. There is a single
  instance of the Server Characteristic Configuration for all clients.
  See Volume 3, Part G, section 3.3.3.4 for more information.

  Priority: Low
  Complexity: C1

- Long write is not implemented. Attribute server, client and command line
  tool shall be changed to support this feature.

  Priority: Low
  Complexity: C2

- Define attribute server API. External applications needs to register,
  change attributes and to be notified about changes. Example: Proximity,
  Time and Alert Profiles. "Local Service hierarchy" in the attribute-api
  needs to be proposed and a RFC shall be sent to the ML.

  Priority: Low
  Complexity: C2
  Owner: Anderson Lizardo <anderson.lizardo@openbossa.org>

Management Interface
====================

- Whitelist support (initially only for LE)

  Priority: Medium
  Complexity: C2
  Owner: Andre Guedes <andre.guedes@openbossa.org>