Bluetooth: Coordinated Set Identification Profile

This document describes how to run the coordinated set identification functionality, both as a client and as a server. Note that in the examples below, some lines of debug have been removed to make this shorter and provide a better overview.

Set Coordinator (Client)

The client will typically be a resource-rich device, such as a smartphone or a laptop. The client is able to lock and release members of a coordinated set. While the coordinated set is locked, no other clients may lock the set.

To lock a set, the client must connect to each of the set members it wants to lock. This implementation will always try to to connect to all the members of the set, and at the same time. Thus if the set size is 3, then BT_MAX_CONN shall be at least 3.

If the locks on set members shall persists through disconnects, it is necessary to bond with the set members. If you need to bond with multiple set members, make sure that BT_MAX_PAIRED is correctly configured.

Using the Set Coordinator

When the Bluetooth stack has been initialized (bt init), and a set member device has been connected, the call control client can be initialized by calling csis_client init, which will start a discovery for the TBS uuids and store the handles, and optionally subscribe to all notifications (default is to subscribe to all).

Once the client has connected and discovered the handles, then it can read the set information, which is needed to identify other set members. The client can then scan for and connect to the remaining set members, and once all the members has been connected to, it can lock and release the set.

It is necessary to enable BT_DEBUG_CSIS_CLIENT to properly use the set coordinator.

csis_client --help
csis_client - Bluetooth CSIS_CLIENT shell commands
Subcommands:
   init              :Initialize CSIS_CLIENT
   discover          :Run discover for CSIS on peer device [member_index]
   discover_members  :Scan for set members <set_pointer>
   lock_set          :Lock set
   release_set       :Release set
   lock              :Lock specific member [member_index]
   release           :Release specific member [member_index]
   lock_get          :Get the lock value of the specific member and instance
                     [member_index [inst_idx]]

Example usage

Setup

uart:~$ init
uart:~$ bt connect xx:xx:xx:xx:xx:xx public

When connected

Discovering sets on a device:

uart:~$ csis_client init
<dbg> bt_csis_client.primary_discover_func: [ATTRIBUTE] handle 0x0048
<dbg> bt_csis_client.primary_discover_func: Discover complete, found 1 instances
<dbg> bt_csis_client.discover_func: Setup complete for 1 / 1
Found 1 sets on device
uart:~$ csis_client discover_sets
<dbg> bt_csis_client.Set SIRK
36 04 9a dc 66 3a a1 a1 |6...f:..
1d 9a 2f 41 01 73 3e 01 |../A.s>.
<dbg> bt_csis_client.csis_client_discover_sets_read_set_size_cb: 2
<dbg> bt_csis_client.csis_client_discover_sets_read_set_lock_cb: 1
<dbg> bt_csis_client.csis_client_discover_sets_read_rank_cb: 1
Set size 2 (pointer: 0x566fdfe8)

Discover set members, based on the set pointer above:

uart:~$ csis_client discover_members 0x566fdfe8
<dbg> bt_csis_client.csis_found: Found CSIS advertiser with address 34:02:86:03:86:c0 (public)
<dbg> bt_csis_client.is_set_member: hash: 0x33ccb1, prand 0x5bfe6a
<dbg> bt_csis_client.is_discovered: 34:02:86:03:86:c0 (public)
<dbg> bt_csis_client.is_discovered: 34:13:e8:b3:7f:9e (public)
<dbg> bt_csis_client.csis_found: Found member (2 / 2)
Discovered 2/2 set members

Lock set members:

uart:~$ csis_client lock_set
<dbg> bt_csis_client.bt_csis_client_lock_set: Connecting to 34:02:86:03:86:c0 (public)
<dbg> bt_csis_client.csis_client_connected: Connected to 34:02:86:03:86:c0 (public)
<dbg> bt_csis_client.discover_func: Setup complete for 1 / 1
<dbg> bt_csis_client.csis_client_lock_set_init_cb:
<dbg> bt_csis_client.Set SIRK
36 04 9a dc 66 3a a1 a1 |6...f:..
1d 9a 2f 41 01 73 3e 01 |../A.s>.
<dbg> bt_csis_client.csis_client_discover_sets_read_set_size_cb: 2
<dbg> bt_csis_client.csis_client_discover_sets_read_set_lock_cb: 1
<dbg> bt_csis_client.csis_client_discover_sets_read_rank_cb: 2
<dbg> bt_csis_client.csis_client_write_lowest_rank: Locking member with rank 1
<dbg> bt_csis_client.notify_func: Instance 0 lock was locked
<dbg> bt_csis_client.csis_client_write_lowest_rank: Locking member with rank 2
<dbg> bt_csis_client.notify_func: Instance 0 lock was locked
Set locked

Release set members:

uart:~$ csis_client release_set
<dbg> bt_csis_client.csis_client_release_highest_rank: Releasing member with rank 2
<dbg> bt_csis_client.notify_func: Instance 0 lock was released
<dbg> bt_csis_client.csis_client_release_highest_rank: Releasing member with rank 1
<dbg> bt_csis_client.notify_func: Instance 0 lock was released
Set released

Coordinated Set Member (Server)

The server on devices that are part of a set, consisting of at least two devices, e.g. a pair of earbuds.

Using the Set Member

csis --help
csis - Bluetooth CSIS shell commands
Subcommands:
   register      :Initialize the service and register callbacks [size <int>]
                  [rank <int>] [not-lockable] [sirk <data>]
   advertise     :Start/stop advertising CSIS PSRIs <on/off>
   update_psri   :Update the advertised PSRI
   lock          :Lock the set
   release       :Release the set [force]
   print_sirk    :Print the currently used SIRK
   set_sirk_rsp  :Set the response used in SIRK requests <accept, accept_enc,
                  reject, oob>

Example Usage

Setup

uart:~$ bt init
uart:~$ csis register
uart:~$ csis advertise on