Bluetooth: Classic: L2CAP Shell

This document describes how to run the Bluetooth Classic L2CAP functionality. The br l2cap command exposes the Bluetooth Classic L2CAP Shell commands.

Commands

The br l2cap commands:

uart:~$ br l2cap
l2cap - [none]
Subcommands:
  register    : <psm> <mode: none, ret, fc, eret, stream> [hold_credit]
                [mode_optional] [extended_control]
  connect     : <psm> <mode: none, ret, fc, eret, stream> [hold_credit]
                [mode_optional] [extended_control]
  disconnect  : [none]
  send        : [number of packets] [length of packet(s)]
  credits     : [none]
  echo        : L2CAP BR ECHO commands
  connless    : L2CAP connectionless commands

The br l2cap echo commands:

uart:~$ br l2cap echo
echo - L2CAP BR ECHO commands
Subcommands:
  register    : [none]
  unregister  : [none]
  req         : <length of data>
  rsp         : <identifier> <length of data>

The br l2cap connless commands:

uart:~$ br l2cap connless
connless - L2CAP connectionless commands
Subcommands:
  register    : <psm> [sec level]
  unregister  : [none]
  send        : <psm> <length of data>

Connection-oriented L2CAP

1. [Server] Register L2CAP Server:

When the Bluetooth stack has been initialized (bt init), the L2CAP server can be registered by calling br l2cap register.

uart:~$ br l2cap register 1001 none
L2CAP psm 4097 registered

2. [Client] Create L2CAP connection:

The command can only be used after the ACL connection has been established.

uart:~$ br l2cap connect 1001 none
L2CAP connection pending

3. L2CAP connection is established:

uart:~$
Security changed: XX:XX:XX:XX:XX:XX level 2
Incoming BR/EDR conn 0x20004848
Channel 0x20000b18 connected
It is basic mode

3. Send L2CAP data to remote:

uart:~$ br l2cap send
Rem 0

4. L2CAP data is received:

uart:~$
Incoming data channel 0x20000b18 len 200
00000000: 00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00 |........ ........|
00000010: 00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00 |........ ........|
00000020: 00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00 |........ ........|
00000030: 00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00 |........ ........|
00000040: 00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00 |........ ........|
00000050: 00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00 |........ ........|
00000060: 00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00 |........ ........|
00000070: 00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00 |........ ........|
00000080: 00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00 |........ ........|
00000090: 00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00 |........ ........|
000000A0: 00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00 |........ ........|
000000B0: 00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00 |........ ........|
000000C0: 00 00 00 00 00 00 00 00                          |........         |

5. Disconnect L2CAP connection:

uart:~$ br l2cap disconnect

6. L2CAP connection is broken:

Channel 0x20000b18 disconnected

L2CAP echo

The echo subcommand provides functionality for L2CAP echo requests and responses in Bluetooth Classic.

The subcommand is controlled by CONFIG_BT_TESTING.

The commands can only be used after the ACL connection has been established.

1. Listen for L2CAP echo request an L2CAP echo response:

uart:~$ br l2cap echo register

2. Stop listening for L2CAP echo request an L2CAP echo response:

uart:~$ br l2cap echo unregister

3. Send L2CAP echo request:

uart:~$ br l2cap echo req 1

4. Echo request is received:

Incoming ECHO REQ data identifier 4 len 1
00000000: 00                                               |.                |

5. Send L2CAP echo response:

uart:~$ br l2cap echo rsp 4 1

6. Echo response is received:

uart:~$
Incoming ECHO RSP data len 1
00000000: 00                                               |.                |

Connectionless L2CAP

The connless subcommand provides functionality for connectionless L2CAP communication in Bluetooth Classic, allowing packet transmission without establishing a L2CAP connection.

The subcommand is controlled by CONFIG_BT_L2CAP_CONNLESS.

The commands can only be used after the ACL connection has been established.

1. Listen for connectionless L2CAP packets:

uart:~$ br l2cap connless register 1001
Register connectionless callbacks with PSM 0x1001

2. Send data

uart:~$ br l2cap connless send 1001 1
Sending connectionless data with PSM 0x1001

3. Connectionless data is received:

Incoming connectionless data psm 0x1001 len 1
00000000: 00                                               |.                |