L2CAP Events

L2CAP events and data packets are delivered to the packet handler specified by l2cap_register_service resp. l2cap_create_channel. Data packets have the L2CAP_DATA_PACKET packet type. L2CAP provides the following events:

  • L2CAP_EVENT_CHANNEL_OPENED - sent if channel establishment is done. Status not equal zero indicates an error. Possible errors: out of memory; connection terminated by local host, when the connection to remote device fails.

  • L2CAP_EVENT_CHANNEL_CLOSED - emitted when channel is closed. No status information is provided.

  • L2CAP_EVENT_INCOMING_CONNECTION - received when the connection is requested by remote. Connection accept and decline are performed with l2cap_accept_connection and l2cap_decline_connecti-on respectively.

  • L2CAP_EVENT_CAN_SEND_NOW - Indicates that an L2CAP data packet could be sent on the reported l2cap_cid. It is emitted after a call to l2cap_request_can_send_now. See Sending L2CAP Data Please note that the guarantee that a packet can be sent is only valid when the event is received. After returning from the packet handler, BTstack might need to send itself.

Event Event Code
L2CAP_EVENT_CHANNEL_OPENED 0x70
L2CAP_EVENT_CHANNEL_CLOSED 0x71
L2CAP_EVENT_INCOMING_CONNECTION 0x72
L2CAP_EVENT_CAN_SEND_NOW 0x78

Table: L2CAP Events.

L2CAP event paramaters, with size in bits:

  • L2CAP_EVENT_CHANNEL_OPENED:
    • event(8), len(8), status(8), address(48), handle(16), psm(16), local_cid(16), remote_cid(16), local_mtu(16), remote_mtu(16)
  • L2CAP_EVENT_CHANNEL_CLOSED:
    • event (8), len(8), channel(16)
  • L2CAP_EVENT_INCOMING_CONNECTION:
    • event(8), len(8), address(48), handle(16), psm (16), local_cid(16), remote_cid (16)
  • L2CAP_EVENT_CAN_SEND_NOW:
    • *event(8), len(8), local_cid(16)

RFCOMM Events

All RFCOMM events and data packets are currently delivered to the packet handler specified by rfcomm_register_packet_handler. Data packets have the _DATA_PACKET packet type. Here is the list of events provided by RFCOMM:

  • RFCOMM_EVENT_INCOMING_CONNECTION - received when the connection is requested by remote. Connection accept and decline are performed with rfcomm_accept_connection and rfcomm_decline_connection respectively.

  • RFCOMM_EVENT_CHANNEL_CLOSED - emitted when channel is closed. No status information is provided.

  • RFCOMM_EVENT_CHANNEL_OPENED - sent if channel establishment is done. Status not equal zero indicates an error. Possible errors: an L2CAP error, out of memory.

  • RFCOMM_EVENT_CAN_SEND_NOW - Indicates that an RFCOMM data packet could be sent on the reported rfcomm_cid. It is emitted after a call to rfcomm_request_can_send_now. See Sending RFCOMM Data Please note that the guarantee that a packet can be sent is only valid when the event is received. After returning from the packet handler, BTstack might need to send itself.

Event Event Code
RFCOMM_EVENT_CHANNEL_OPENED 0x80
RFCOMM_EVENT_CHANNEL_CLOSED 0x81
RFCOMM_EVENT_INCOMING_CONNECTION 0x82
RFCOMM_EVENT_CAN_SEND_NOW 0x89

Table: RFCOMM Events.

RFCOMM event paramaters, with size in bits:

  • RFCOMM_EVENT_CHANNEL_OPENED:
    • event(8), len(8), status(8), address(48), handle(16), server_channel(8), rfcomm_cid(16), max_frame_size(16)
  • RFCOMM_EVENT_CHANNEL_CLOSED:
    • event(8), len(8), rfcomm_cid(16)
  • RFCOMM_EVENT_INCOMING_CONNECTION:
    • event(8), len(8), address(48), channel (8), rfcomm_cid(16)
  • RFCOMM_EVENT_CAN_SEND_NOW:
    • *event(8), len(8), rfcomm_cid(16)

Errors

Error Error Code
BTSTACK_MEMORY_ALLOC_FAILED 0x56
BTSTACK_ACL_BUFFERS_FULL 0x57
L2CAP_COMMAND_REJECT_REASON_COMMAND_NOT_UNDERSTOOD 0x60
L2CAP_COMMAND_REJECT_REASON_SIGNALING_MTU_EXCEEDED 0x61
L2CAP_COMMAND_REJECT_REASON_INVALID_CID_IN_REQUEST 0x62
L2CAP_CONNECTION_RESPONSE_RESULT_SUCCESSFUL 0x63
L2CAP_CONNECTION_RESPONSE_RESULT_PENDING 0x64
L2CAP_CONNECTION_RESPONSE_RESULT_REFUSED_PSM 0x65
L2CAP_CONNECTION_RESPONSE_RESULT_REFUSED_SECURITY 0x66
L2CAP_CONNECTION_RESPONSE_RESULT_REFUSED_RESOURCES 0x65
L2CAP_CONFIG_RESPONSE_RESULT_SUCCESSFUL 0x66
L2CAP_CONFIG_RESPONSE_RESULT_UNACCEPTABLE_PARAMS 0x67
L2CAP_CONFIG_RESPONSE_RESULT_REJECTED 0x68
L2CAP_CONFIG_RESPONSE_RESULT_UNKNOWN_OPTIONS 0x69
L2CAP_SERVICE_ALREADY_REGISTERED 0x6a
RFCOMM_MULTIPLEXER_STOPPED 0x70
RFCOMM_NO_OUTGOING_CREDITS 0x72
SDP_HANDLE_ALREADY_REGISTERED 0x80

Table: Errors.