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bumble_fork/bumble/l2cap.py
Josh Wu 6091e6365d Remove depreacated L2CAP APIs
2025-08-27 14:15:08 +08:00

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# Copyright 2021-2022 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# -----------------------------------------------------------------------------
# Imports
# -----------------------------------------------------------------------------
from __future__ import annotations
import asyncio
import dataclasses
import enum
import logging
import struct
from collections import deque
from collections.abc import Sequence
from typing import (
TYPE_CHECKING,
Any,
Callable,
ClassVar,
Iterable,
Optional,
SupportsBytes,
TypeVar,
Union,
)
from bumble import hci, utils
from bumble.colors import color
from bumble.core import (
InvalidArgumentError,
InvalidPacketError,
InvalidStateError,
OutOfResourcesError,
ProtocolError,
)
if TYPE_CHECKING:
from bumble.device import Connection
from bumble.host import Host
# -----------------------------------------------------------------------------
# Logging
# -----------------------------------------------------------------------------
logger = logging.getLogger(__name__)
# -----------------------------------------------------------------------------
# Constants
# -----------------------------------------------------------------------------
# fmt: off
# pylint: disable=line-too-long
L2CAP_SIGNALING_CID = 0x01
L2CAP_LE_SIGNALING_CID = 0x05
L2CAP_MIN_LE_MTU = 23
L2CAP_MIN_BR_EDR_MTU = 48
L2CAP_MAX_BR_EDR_MTU = 65535
L2CAP_DEFAULT_MTU = 2048 # Default value for the MTU we are willing to accept
L2CAP_DEFAULT_CONNECTIONLESS_MTU = 1024
# See Bluetooth spec @ Vol 3, Part A - Table 2.1: CID name space on ACL-U, ASB-U, and AMP-U logical links
L2CAP_ACL_U_DYNAMIC_CID_RANGE_START = 0x0040
L2CAP_ACL_U_DYNAMIC_CID_RANGE_END = 0xFFFF
# See Bluetooth spec @ Vol 3, Part A - Table 2.2: CID name space on LE-U logical link
L2CAP_LE_U_DYNAMIC_CID_RANGE_START = 0x0040
L2CAP_LE_U_DYNAMIC_CID_RANGE_END = 0x007F
# PSM Range - See Bluetooth spec @ Vol 3, Part A / Table 4.5: PSM ranges and usage
L2CAP_PSM_DYNAMIC_RANGE_START = 0x1001
L2CAP_PSM_DYNAMIC_RANGE_END = 0xFFFF
# LE PSM Ranges - See Bluetooth spec @ Vol 3, Part A / Table 4.19: LE Credit Based Connection Request LE_PSM ranges
L2CAP_LE_PSM_DYNAMIC_RANGE_START = 0x0080
L2CAP_LE_PSM_DYNAMIC_RANGE_END = 0x00FF
class CommandCode(hci.SpecableEnum):
L2CAP_COMMAND_REJECT = 0x01
L2CAP_CONNECTION_REQUEST = 0x02
L2CAP_CONNECTION_RESPONSE = 0x03
L2CAP_CONFIGURE_REQUEST = 0x04
L2CAP_CONFIGURE_RESPONSE = 0x05
L2CAP_DISCONNECTION_REQUEST = 0x06
L2CAP_DISCONNECTION_RESPONSE = 0x07
L2CAP_ECHO_REQUEST = 0x08
L2CAP_ECHO_RESPONSE = 0x09
L2CAP_INFORMATION_REQUEST = 0x0A
L2CAP_INFORMATION_RESPONSE = 0x0B
L2CAP_CREATE_CHANNEL_REQUEST = 0x0C
L2CAP_CREATE_CHANNEL_RESPONSE = 0x0D
L2CAP_MOVE_CHANNEL_REQUEST = 0x0E
L2CAP_MOVE_CHANNEL_RESPONSE = 0x0F
L2CAP_MOVE_CHANNEL_CONFIRMATION = 0x10
L2CAP_MOVE_CHANNEL_CONFIRMATION_RESPONSE = 0x11
L2CAP_CONNECTION_PARAMETER_UPDATE_REQUEST = 0x12
L2CAP_CONNECTION_PARAMETER_UPDATE_RESPONSE = 0x13
L2CAP_LE_CREDIT_BASED_CONNECTION_REQUEST = 0x14
L2CAP_LE_CREDIT_BASED_CONNECTION_RESPONSE = 0x15
L2CAP_LE_FLOW_CONTROL_CREDIT = 0x16
L2CAP_CREDIT_BASED_CONNECTION_REQUEST = 0x17
L2CAP_CREDIT_BASED_CONNECTION_RESPONSE = 0x18
L2CAP_CREDIT_BASED_RECONFIGURE_REQUEST = 0x19
L2CAP_CREDIT_BASED_RECONFIGURE_RESPONSE = 0x1A
L2CAP_CONNECTION_PARAMETERS_ACCEPTED_RESULT = 0x0000
L2CAP_CONNECTION_PARAMETERS_REJECTED_RESULT = 0x0001
L2CAP_COMMAND_NOT_UNDERSTOOD_REASON = 0x0000
L2CAP_SIGNALING_MTU_EXCEEDED_REASON = 0x0001
L2CAP_INVALID_CID_IN_REQUEST_REASON = 0x0002
L2CAP_LE_CREDIT_BASED_CONNECTION_MAX_CREDITS = 65535
L2CAP_LE_CREDIT_BASED_CONNECTION_MIN_MTU = 23
L2CAP_LE_CREDIT_BASED_CONNECTION_MAX_MTU = 65535
L2CAP_LE_CREDIT_BASED_CONNECTION_MIN_MPS = 23
L2CAP_LE_CREDIT_BASED_CONNECTION_MAX_MPS = 65533
L2CAP_LE_CREDIT_BASED_CONNECTION_DEFAULT_MTU = 2048
L2CAP_LE_CREDIT_BASED_CONNECTION_DEFAULT_MPS = 2048
L2CAP_LE_CREDIT_BASED_CONNECTION_DEFAULT_INITIAL_CREDITS = 256
L2CAP_MAXIMUM_TRANSMISSION_UNIT_CONFIGURATION_OPTION_TYPE = 0x01
L2CAP_MTU_CONFIGURATION_PARAMETER_TYPE = 0x01
# fmt: on
# pylint: enable=line-too-long
# -----------------------------------------------------------------------------
# Classes
# -----------------------------------------------------------------------------
# pylint: disable=invalid-name
@dataclasses.dataclass
class ClassicChannelSpec:
psm: Optional[int] = None
mtu: int = L2CAP_DEFAULT_MTU
@dataclasses.dataclass
class LeCreditBasedChannelSpec:
psm: Optional[int] = None
mtu: int = L2CAP_LE_CREDIT_BASED_CONNECTION_DEFAULT_MTU
mps: int = L2CAP_LE_CREDIT_BASED_CONNECTION_DEFAULT_MPS
max_credits: int = L2CAP_LE_CREDIT_BASED_CONNECTION_DEFAULT_INITIAL_CREDITS
def __post_init__(self):
if (
self.max_credits < 1
or self.max_credits > L2CAP_LE_CREDIT_BASED_CONNECTION_MAX_CREDITS
):
raise InvalidArgumentError('max credits out of range')
if (
self.mtu < L2CAP_LE_CREDIT_BASED_CONNECTION_MIN_MTU
or self.mtu > L2CAP_LE_CREDIT_BASED_CONNECTION_MAX_MTU
):
raise InvalidArgumentError('MTU out of range')
if (
self.mps < L2CAP_LE_CREDIT_BASED_CONNECTION_MIN_MPS
or self.mps > L2CAP_LE_CREDIT_BASED_CONNECTION_MAX_MPS
):
raise InvalidArgumentError('MPS out of range')
class L2CAP_PDU:
'''
See Bluetooth spec @ Vol 3, Part A - 3 DATA PACKET FORMAT
'''
@staticmethod
def from_bytes(data: bytes) -> L2CAP_PDU:
# Check parameters
if len(data) < 4:
raise InvalidPacketError('not enough data for L2CAP header')
_, l2cap_pdu_cid = struct.unpack_from('<HH', data, 0)
l2cap_pdu_payload = data[4:]
return L2CAP_PDU(l2cap_pdu_cid, l2cap_pdu_payload)
def __bytes__(self) -> bytes:
header = struct.pack('<HH', len(self.payload), self.cid)
return header + self.payload
def __init__(self, cid: int, payload: bytes) -> None:
self.cid = cid
self.payload = payload
def __str__(self) -> str:
return f'{color("L2CAP", "green")} [CID={self.cid}]: {self.payload.hex()}'
# -----------------------------------------------------------------------------
@dataclasses.dataclass
class L2CAP_Control_Frame:
'''
See Bluetooth spec @ Vol 3, Part A - 4 SIGNALING PACKET FORMATS
'''
classes: ClassVar[dict[int, type[L2CAP_Control_Frame]]] = {}
fields: ClassVar[hci.Fields] = ()
code: int = dataclasses.field(default=0, init=False)
name: str = dataclasses.field(default='', init=False)
_payload: Optional[bytes] = dataclasses.field(default=None, init=False)
identifier: int
@classmethod
def from_bytes(cls, pdu: bytes) -> L2CAP_Control_Frame:
code, identifier, length = struct.unpack_from("<BBH", pdu)
subclass = L2CAP_Control_Frame.classes.get(code)
if subclass is None:
instance = L2CAP_Control_Frame(identifier=identifier)
instance.payload = pdu[4:]
instance.code = CommandCode(code)
instance.name = instance.code.name
return instance
frame = subclass(
**hci.HCI_Object.dict_from_bytes(pdu, 4, subclass.fields),
identifier=identifier,
)
frame.identifier = identifier
frame.payload = pdu[4:]
if length != len(frame.payload):
logger.warning(
color(
f'!!! length mismatch: expected {length} but got {len(frame.payload)}',
'red',
)
)
return frame
@staticmethod
def decode_configuration_options(data: bytes) -> list[tuple[int, bytes]]:
options = []
while len(data) >= 2:
value_type = data[0]
length = data[1]
value = data[2 : 2 + length]
data = data[2 + length :]
options.append((value_type, value))
return options
@staticmethod
def encode_configuration_options(options: list[tuple[int, bytes]]) -> bytes:
return b''.join(
[bytes([option[0], len(option[1])]) + option[1] for option in options]
)
_ControlFrame = TypeVar('_ControlFrame', bound='L2CAP_Control_Frame')
@classmethod
def subclass(cls, subclass: type[_ControlFrame]) -> type[_ControlFrame]:
subclass.name = subclass.__name__.upper()
subclass.code = CommandCode[subclass.name]
subclass.fields = hci.HCI_Object.fields_from_dataclass(subclass)
# Register a factory for this class
L2CAP_Control_Frame.classes[subclass.code] = subclass
return subclass
@property
def payload(self) -> bytes:
if self._payload is None:
self._payload = hci.HCI_Object.dict_to_bytes(self.__dict__, self.fields)
return self._payload
@payload.setter
def payload(self, payload: bytes) -> None:
self._payload = payload
def __bytes__(self) -> bytes:
return (
struct.pack('<BBH', self.code, self.identifier, len(self.payload))
+ self.payload
)
def __str__(self) -> str:
result = f'{color(self.name, "yellow")} [ID={self.identifier}]'
if fields := getattr(self, 'fields', None):
result += ':\n' + hci.HCI_Object.format_fields(self.__dict__, fields, ' ')
else:
if len(self.payload) > 1:
result += f': {self.payload.hex()}'
return result
# -----------------------------------------------------------------------------
@L2CAP_Control_Frame.subclass
@dataclasses.dataclass
class L2CAP_Command_Reject(L2CAP_Control_Frame):
'''
See Bluetooth spec @ Vol 3, Part A - 4.1 COMMAND REJECT
'''
class Reason(hci.SpecableEnum):
COMMAND_NOT_UNDERSTOOD = 0x0000
SIGNALING_MTU_EXCEEDED = 0x0001
INVALID_CID_IN_REQUEST = 0x0002
reason: int = dataclasses.field(metadata=Reason.type_metadata(2))
data: bytes = dataclasses.field(metadata=hci.metadata('*'))
# -----------------------------------------------------------------------------
@L2CAP_Control_Frame.subclass
@dataclasses.dataclass
class L2CAP_Connection_Request(L2CAP_Control_Frame):
'''
See Bluetooth spec @ Vol 3, Part A - 4.2 CONNECTION REQUEST
'''
@staticmethod
def parse_psm(data: bytes, offset: int = 0) -> tuple[int, int]:
psm_length = 2
psm = data[offset] | data[offset + 1] << 8
# The PSM field extends until the first even octet (inclusive)
while data[offset + psm_length - 1] % 2 == 1:
psm |= data[offset + psm_length] << (8 * psm_length)
psm_length += 1
return offset + psm_length, psm
@staticmethod
def serialize_psm(psm: int) -> bytes:
serialized = struct.pack('<H', psm & 0xFFFF)
psm >>= 16
while psm:
serialized += bytes([psm & 0xFF])
psm >>= 8
return serialized
psm: int = dataclasses.field(
metadata=hci.metadata(
{
'parser': lambda data, offset: L2CAP_Connection_Request.parse_psm(
data, offset
),
'serializer': lambda value: L2CAP_Connection_Request.serialize_psm(
value
),
}
)
)
source_cid: int = dataclasses.field(metadata=hci.metadata(2))
# -----------------------------------------------------------------------------
@L2CAP_Control_Frame.subclass
@dataclasses.dataclass
class L2CAP_Connection_Response(L2CAP_Control_Frame):
'''
See Bluetooth spec @ Vol 3, Part A - 4.3 CONNECTION RESPONSE
'''
class Result(hci.SpecableEnum):
CONNECTION_SUCCESSFUL = 0x0000
CONNECTION_PENDING = 0x0001
CONNECTION_REFUSED_PSM_NOT_SUPPORTED = 0x0002
CONNECTION_REFUSED_SECURITY_BLOCK = 0x0003
CONNECTION_REFUSED_NO_RESOURCES_AVAILABLE = 0x0004
CONNECTION_REFUSED_INVALID_SOURCE_CID = 0x0006
CONNECTION_REFUSED_SOURCE_CID_ALREADY_ALLOCATED = 0x0007
CONNECTION_REFUSED_UNACCEPTABLE_PARAMETERS = 0x000B
destination_cid: int = dataclasses.field(metadata=hci.metadata(2))
source_cid: int = dataclasses.field(metadata=hci.metadata(2))
result: int = dataclasses.field(metadata=Result.type_metadata(2))
status: int = dataclasses.field(metadata=hci.metadata(2))
# -----------------------------------------------------------------------------
@L2CAP_Control_Frame.subclass
@dataclasses.dataclass
class L2CAP_Configure_Request(L2CAP_Control_Frame):
'''
See Bluetooth spec @ Vol 3, Part A - 4.4 CONFIGURATION REQUEST
'''
destination_cid: int = dataclasses.field(metadata=hci.metadata(2))
flags: int = dataclasses.field(metadata=hci.metadata(2))
options: bytes = dataclasses.field(metadata=hci.metadata('*'))
# -----------------------------------------------------------------------------
@L2CAP_Control_Frame.subclass
@dataclasses.dataclass
class L2CAP_Configure_Response(L2CAP_Control_Frame):
'''
See Bluetooth spec @ Vol 3, Part A - 4.5 CONFIGURATION RESPONSE
'''
class Result(hci.SpecableEnum):
SUCCESS = 0x0000
FAILURE_UNACCEPTABLE_PARAMETERS = 0x0001
FAILURE_REJECTED = 0x0002
FAILURE_UNKNOWN_OPTIONS = 0x0003
PENDING = 0x0004
FAILURE_FLOW_SPEC_REJECTED = 0x0005
source_cid: int = dataclasses.field(metadata=hci.metadata(2))
flags: int = dataclasses.field(metadata=hci.metadata(2))
result: int = dataclasses.field(metadata=Result.type_metadata(2))
options: bytes = dataclasses.field(metadata=hci.metadata('*'))
# -----------------------------------------------------------------------------
@L2CAP_Control_Frame.subclass
@dataclasses.dataclass
class L2CAP_Disconnection_Request(L2CAP_Control_Frame):
'''
See Bluetooth spec @ Vol 3, Part A - 4.6 DISCONNECTION REQUEST
'''
destination_cid: int = dataclasses.field(metadata=hci.metadata(2))
source_cid: int = dataclasses.field(metadata=hci.metadata(2))
# -----------------------------------------------------------------------------
@L2CAP_Control_Frame.subclass
@dataclasses.dataclass
class L2CAP_Disconnection_Response(L2CAP_Control_Frame):
'''
See Bluetooth spec @ Vol 3, Part A - 4.7 DISCONNECTION RESPONSE
'''
destination_cid: int = dataclasses.field(metadata=hci.metadata(2))
source_cid: int = dataclasses.field(metadata=hci.metadata(2))
# -----------------------------------------------------------------------------
@L2CAP_Control_Frame.subclass
@dataclasses.dataclass
class L2CAP_Echo_Request(L2CAP_Control_Frame):
'''
See Bluetooth spec @ Vol 3, Part A - 4.8 ECHO REQUEST
'''
data: bytes = dataclasses.field(metadata=hci.metadata('*'))
# -----------------------------------------------------------------------------
@L2CAP_Control_Frame.subclass
@dataclasses.dataclass
class L2CAP_Echo_Response(L2CAP_Control_Frame):
'''
See Bluetooth spec @ Vol 3, Part A - 4.9 ECHO RESPONSE
'''
data: bytes = dataclasses.field(metadata=hci.metadata('*'))
# -----------------------------------------------------------------------------
@L2CAP_Control_Frame.subclass
@dataclasses.dataclass
class L2CAP_Information_Request(L2CAP_Control_Frame):
'''
See Bluetooth spec @ Vol 3, Part A - 4.10 INFORMATION REQUEST
'''
class InfoType(hci.SpecableEnum):
CONNECTIONLESS_MTU = 0x0001
EXTENDED_FEATURES_SUPPORTED = 0x0002
FIXED_CHANNELS_SUPPORTED = 0x0003
EXTENDED_FEATURE_FLOW_MODE_CONTROL = 0x0001
EXTENDED_FEATURE_RETRANSMISSION_MODE = 0x0002
EXTENDED_FEATURE_BIDIRECTIONAL_QOS = 0x0004
EXTENDED_FEATURE_ENHANCED_RETRANSMISSION_MODE = 0x0008
EXTENDED_FEATURE_STREAMING_MODE = 0x0010
EXTENDED_FEATURE_FCS_OPTION = 0x0020
EXTENDED_FEATURE_EXTENDED_FLOW_SPEC = 0x0040
EXTENDED_FEATURE_FIXED_CHANNELS = 0x0080
EXTENDED_FEATURE_EXTENDED_WINDOW_SIZE = 0x0100
EXTENDED_FEATURE_UNICAST_CONNECTIONLESS_DATA = 0x0200
EXTENDED_FEATURE_ENHANCED_CREDIT_BASE_FLOW_CONTROL = 0x0400
info_type: int = dataclasses.field(metadata=InfoType.type_metadata(2))
# -----------------------------------------------------------------------------
@L2CAP_Control_Frame.subclass
@dataclasses.dataclass
class L2CAP_Information_Response(L2CAP_Control_Frame):
'''
See Bluetooth spec @ Vol 3, Part A - 4.11 INFORMATION RESPONSE
'''
class Result(hci.SpecableEnum):
SUCCESS = 0x00
NOT_SUPPORTED = 0x01
info_type: int = dataclasses.field(
metadata=L2CAP_Information_Request.InfoType.type_metadata(2)
)
result: int = dataclasses.field(metadata=Result.type_metadata(2))
data: bytes = dataclasses.field(metadata=hci.metadata('*'))
# -----------------------------------------------------------------------------
@L2CAP_Control_Frame.subclass
@dataclasses.dataclass
class L2CAP_Connection_Parameter_Update_Request(L2CAP_Control_Frame):
'''
See Bluetooth spec @ Vol 3, Part A - 4.20 CONNECTION PARAMETER UPDATE REQUEST
'''
interval_min: int = dataclasses.field(metadata=hci.metadata(2))
interval_max: int = dataclasses.field(metadata=hci.metadata(2))
latency: int = dataclasses.field(metadata=hci.metadata(2))
timeout: int = dataclasses.field(metadata=hci.metadata(2))
# -----------------------------------------------------------------------------
@L2CAP_Control_Frame.subclass
@dataclasses.dataclass
class L2CAP_Connection_Parameter_Update_Response(L2CAP_Control_Frame):
'''
See Bluetooth spec @ Vol 3, Part A - 4.21 CONNECTION PARAMETER UPDATE RESPONSE
'''
result: int = dataclasses.field(metadata=hci.metadata(2))
# -----------------------------------------------------------------------------
@L2CAP_Control_Frame.subclass
@dataclasses.dataclass
class L2CAP_LE_Credit_Based_Connection_Request(L2CAP_Control_Frame):
'''
See Bluetooth spec @ Vol 3, Part A - 4.22 LE CREDIT BASED CONNECTION REQUEST
(CODE 0x14)
'''
le_psm: int = dataclasses.field(metadata=hci.metadata(2))
source_cid: int = dataclasses.field(metadata=hci.metadata(2))
mtu: int = dataclasses.field(metadata=hci.metadata(2))
mps: int = dataclasses.field(metadata=hci.metadata(2))
initial_credits: int = dataclasses.field(metadata=hci.metadata(2))
# -----------------------------------------------------------------------------
@L2CAP_Control_Frame.subclass
@dataclasses.dataclass
class L2CAP_LE_Credit_Based_Connection_Response(L2CAP_Control_Frame):
'''
See Bluetooth spec @ Vol 3, Part A - 4.23 LE CREDIT BASED CONNECTION RESPONSE
(CODE 0x15)
'''
class Result(hci.SpecableEnum):
CONNECTION_SUCCESSFUL = 0x0000
CONNECTION_REFUSED_LE_PSM_NOT_SUPPORTED = 0x0002
CONNECTION_REFUSED_NO_RESOURCES_AVAILABLE = 0x0004
CONNECTION_REFUSED_INSUFFICIENT_AUTHENTICATION = 0x0005
CONNECTION_REFUSED_INSUFFICIENT_AUTHORIZATION = 0x0006
CONNECTION_REFUSED_INSUFFICIENT_ENCRYPTION_KEY_SIZE = 0x0007
CONNECTION_REFUSED_INSUFFICIENT_ENCRYPTION = 0x0008
CONNECTION_REFUSED_INVALID_SOURCE_CID = 0x0009
CONNECTION_REFUSED_SOURCE_CID_ALREADY_ALLOCATED = 0x000A
CONNECTION_REFUSED_UNACCEPTABLE_PARAMETERS = 0x000B
destination_cid: int = dataclasses.field(metadata=hci.metadata(2))
mtu: int = dataclasses.field(metadata=hci.metadata(2))
mps: int = dataclasses.field(metadata=hci.metadata(2))
initial_credits: int = dataclasses.field(metadata=hci.metadata(2))
result: int = dataclasses.field(metadata=Result.type_metadata(2))
# -----------------------------------------------------------------------------
@L2CAP_Control_Frame.subclass
@dataclasses.dataclass
class L2CAP_LE_Flow_Control_Credit(L2CAP_Control_Frame):
'''
See Bluetooth spec @ Vol 3, Part A - 4.24 LE FLOW CONTROL CREDIT (CODE 0x16)
'''
cid: int = dataclasses.field(metadata=hci.metadata(2))
credits: int = dataclasses.field(metadata=hci.metadata(2))
# -----------------------------------------------------------------------------
@L2CAP_Control_Frame.subclass
@dataclasses.dataclass
class L2CAP_Credit_Based_Connection_Request(L2CAP_Control_Frame):
'''
See Bluetooth spec @ Vol 3, Part A - 4.25 L2CAP_CREDIT_BASED_CONNECTION_REQ (0x17).
'''
@classmethod
def parse_cid_list(cls, data: bytes, offset: int) -> tuple[int, list[int]]:
count = (len(data) - offset) // 2
return len(data), list(struct.unpack_from("<" + ("H" * count), data, offset))
@classmethod
def serialize_cid_list(cls, cids: Sequence[int]) -> bytes:
return b"".join([struct.pack("<H", cid) for cid in cids])
CID_METADATA: ClassVar[dict[str, Any]] = hci.metadata(
{
'parser': lambda data, offset: L2CAP_Credit_Based_Connection_Request.parse_cid_list(
data, offset
),
'serializer': lambda value: L2CAP_Credit_Based_Connection_Request.serialize_cid_list(
value
),
}
)
spsm: int = dataclasses.field(metadata=hci.metadata(2))
mtu: int = dataclasses.field(metadata=hci.metadata(2))
mps: int = dataclasses.field(metadata=hci.metadata(2))
initial_credits: int = dataclasses.field(metadata=hci.metadata(2))
source_cid: Sequence[int] = dataclasses.field(metadata=CID_METADATA)
# -----------------------------------------------------------------------------
@L2CAP_Control_Frame.subclass
@dataclasses.dataclass
class L2CAP_Credit_Based_Connection_Response(L2CAP_Control_Frame):
'''
See Bluetooth spec @ Vol 3, Part A - 4.26 L2CAP_CREDIT_BASED_CONNECTION_RSP (0x18).
'''
class Result(hci.SpecableEnum):
ALL_CONNECTIONS_SUCCESSFUL = 0x0000
ALL_CONNECTIONS_REFUSED_SPSM_NOT_SUPPORTED = 0x0002
SOME_CONNECTIONS_REFUSED_INSUFFICIENT_RESOURCES_AVAILABLE = 0x0004
ALL_CONNECTIONS_REFUSED_INSUFFICIENT_AUTHENTICATION = 0x0005
ALL_CONNECTIONS_REFUSED_INSUFFICIENT_AUTHORIZATION = 0x0006
ALL_CONNECTIONS_REFUSED_ENCRYPTION_KEY_SIZE_TOO_SHORT = 0x0007
ALL_CONNECTIONS_REFUSED_INSUFFICIENT_ENCRYPTION = 0x0008
SOME_CONNECTIONS_REFUSED_INVALID_SOURCE_CID = 0x0009
SOME_CONNECTIONS_REFUSED_SOURCE_CID_ALREADY_ALLOCATED = 0x000A
ALL_CONNECTIONS_REFUSED_UNACCEPTABLE_PARAMETERS = 0x000B
ALL_CONNECTIONS_REFUSED_INVALID_PARAMETERS = 0x000C
ALL_CONNECTIONS_PENDING_NO_FURTHER_INFORMATION_AVAILABLE = 0x000D
ALL_CONNECTIONS_PENDING_AUTHENTICATION_PENDING = 0x000E
ALL_CONNECTIONS_PENDING_AUTHORIZATION_PENDING = 0x000F
mtu: int = dataclasses.field(metadata=hci.metadata(2))
mps: int = dataclasses.field(metadata=hci.metadata(2))
initial_credits: int = dataclasses.field(metadata=hci.metadata(2))
result: int = dataclasses.field(metadata=Result.type_metadata(2))
destination_cid: Sequence[int] = dataclasses.field(
metadata=L2CAP_Credit_Based_Connection_Request.CID_METADATA
)
# -----------------------------------------------------------------------------
@L2CAP_Control_Frame.subclass
@dataclasses.dataclass
class L2CAP_Credit_Based_Reconfigure_Request(L2CAP_Control_Frame):
'''
See Bluetooth spec @ Vol 3, Part A - 4.27 L2CAP_CREDIT_BASED_RECONFIGURE_REQ (0x19).
'''
mtu: int = dataclasses.field(metadata=hci.metadata(2))
mps: int = dataclasses.field(metadata=hci.metadata(2))
destination_cid: Sequence[int] = dataclasses.field(
metadata=L2CAP_Credit_Based_Connection_Request.CID_METADATA
)
# -----------------------------------------------------------------------------
@L2CAP_Control_Frame.subclass
@dataclasses.dataclass
class L2CAP_Credit_Based_Reconfigure_Response(L2CAP_Control_Frame):
'''
See Bluetooth spec @ Vol 3, Part A - 4.28 L2CAP_CREDIT_BASED_RECONFIGURE_RSP (0x1A).
'''
class Result(hci.SpecableEnum):
RECONFIGURATION_SUCCESSFUL = 0x0000
RECONFIGURATION_FAILED_REDUCTION_IN_SIZE_OF_MTU_NOT_ALLOWED = 0x0001
RECONFIGURATION_FAILED_REDUCTION_IN_SIZE_OF_MPS_NOT_ALLOWED_FOR_MORE_THAN_ONE_CHANNEL_AT_A_TIME = (
0x0002
)
RECONFIGURATION_FAILED_ONE_OR_MORE_DESTINATION_CIDS_INVALID = 0x0003
RECONFIGURATION_FAILED_OTHER_UNACCEPTABLE_PARAMETERS = 0x0004
result: int = dataclasses.field(metadata=Result.type_metadata(2))
# -----------------------------------------------------------------------------
class ClassicChannel(utils.EventEmitter):
class State(enum.IntEnum):
# States
CLOSED = 0x00
WAIT_CONNECT = 0x01
WAIT_CONNECT_RSP = 0x02
OPEN = 0x03
WAIT_DISCONNECT = 0x04
WAIT_CREATE = 0x05
WAIT_CREATE_RSP = 0x06
WAIT_MOVE = 0x07
WAIT_MOVE_RSP = 0x08
WAIT_MOVE_CONFIRM = 0x09
WAIT_CONFIRM_RSP = 0x0A
# CONFIG substates
WAIT_CONFIG = 0x10
WAIT_SEND_CONFIG = 0x11
WAIT_CONFIG_REQ_RSP = 0x12
WAIT_CONFIG_RSP = 0x13
WAIT_CONFIG_REQ = 0x14
WAIT_IND_FINAL_RSP = 0x15
WAIT_FINAL_RSP = 0x16
WAIT_CONTROL_IND = 0x17
EVENT_OPEN = "open"
EVENT_CLOSE = "close"
connection_result: Optional[asyncio.Future[None]]
disconnection_result: Optional[asyncio.Future[None]]
response: Optional[asyncio.Future[bytes]]
sink: Optional[Callable[[bytes], Any]]
state: State
connection: Connection
mtu: int
peer_mtu: int
def __init__(
self,
manager: ChannelManager,
connection: Connection,
signaling_cid: int,
psm: int,
source_cid: int,
mtu: int,
) -> None:
super().__init__()
self.manager = manager
self.connection = connection
self.signaling_cid = signaling_cid
self.state = self.State.CLOSED
self.mtu = mtu
self.peer_mtu = L2CAP_MIN_BR_EDR_MTU
self.psm = psm
self.source_cid = source_cid
self.destination_cid = 0
self.connection_result = None
self.disconnection_result = None
self.sink = None
def _change_state(self, new_state: State) -> None:
logger.debug(f'{self} state change -> {color(new_state.name, "cyan")}')
self.state = new_state
def send_pdu(self, pdu: Union[SupportsBytes, bytes]) -> None:
if self.state != self.State.OPEN:
raise InvalidStateError('channel not open')
self.manager.send_pdu(self.connection, self.destination_cid, pdu)
def send_control_frame(self, frame: L2CAP_Control_Frame) -> None:
self.manager.send_control_frame(self.connection, self.signaling_cid, frame)
def on_pdu(self, pdu: bytes) -> None:
if self.sink:
# pylint: disable=not-callable
self.sink(pdu)
else:
logger.warning(
color('received pdu without a pending request or sink', 'red')
)
async def connect(self) -> None:
if self.state != self.State.CLOSED:
raise InvalidStateError('invalid state')
# Check that we can start a new connection
if self.connection_result:
raise InvalidStateError('connection already pending')
self._change_state(self.State.WAIT_CONNECT_RSP)
self.send_control_frame(
L2CAP_Connection_Request(
identifier=self.manager.next_identifier(self.connection),
psm=self.psm,
source_cid=self.source_cid,
)
)
# Create a future to wait for the state machine to get to a success or error
# state
self.connection_result = asyncio.get_running_loop().create_future()
# Wait for the connection to succeed or fail
try:
return await self.connection.cancel_on_disconnection(self.connection_result)
finally:
self.connection_result = None
async def disconnect(self) -> None:
if self.state != self.State.OPEN:
raise InvalidStateError('invalid state')
self._change_state(self.State.WAIT_DISCONNECT)
self.send_control_frame(
L2CAP_Disconnection_Request(
identifier=self.manager.next_identifier(self.connection),
destination_cid=self.destination_cid,
source_cid=self.source_cid,
)
)
# Create a future to wait for the state machine to get to a success or error
# state
self.disconnection_result = asyncio.get_running_loop().create_future()
return await self.disconnection_result
def abort(self) -> None:
if self.state == self.State.OPEN:
self._change_state(self.State.CLOSED)
self.emit(self.EVENT_CLOSE)
def send_configure_request(self) -> None:
options = L2CAP_Control_Frame.encode_configuration_options(
[
(
L2CAP_MAXIMUM_TRANSMISSION_UNIT_CONFIGURATION_OPTION_TYPE,
struct.pack('<H', self.mtu),
)
]
)
self.send_control_frame(
L2CAP_Configure_Request(
identifier=self.manager.next_identifier(self.connection),
destination_cid=self.destination_cid,
flags=0x0000,
options=options,
)
)
def on_connection_request(self, request: L2CAP_Connection_Request) -> None:
self.destination_cid = request.source_cid
self._change_state(self.State.WAIT_CONNECT)
self.send_control_frame(
L2CAP_Connection_Response(
identifier=request.identifier,
destination_cid=self.source_cid,
source_cid=self.destination_cid,
result=L2CAP_Connection_Response.Result.CONNECTION_SUCCESSFUL,
status=0x0000,
)
)
self._change_state(self.State.WAIT_CONFIG)
self.send_configure_request()
self._change_state(self.State.WAIT_CONFIG_REQ_RSP)
def on_connection_response(self, response: L2CAP_Connection_Response):
if self.state != self.State.WAIT_CONNECT_RSP:
logger.warning(color('invalid state', 'red'))
return
if response.result == L2CAP_Connection_Response.Result.CONNECTION_SUCCESSFUL:
self.destination_cid = response.destination_cid
self._change_state(self.State.WAIT_CONFIG)
self.send_configure_request()
self._change_state(self.State.WAIT_CONFIG_REQ_RSP)
elif response.result == L2CAP_Connection_Response.Result.CONNECTION_PENDING:
pass
else:
self._change_state(self.State.CLOSED)
if self.connection_result:
self.connection_result.set_exception(
ProtocolError(
response.result,
'l2cap',
L2CAP_Connection_Response.Result(response.result).name,
)
)
self.connection_result = None
def on_configure_request(self, request: L2CAP_Configure_Request) -> None:
if self.state not in (
self.State.WAIT_CONFIG,
self.State.WAIT_CONFIG_REQ,
self.State.WAIT_CONFIG_REQ_RSP,
):
logger.warning(color('invalid state', 'red'))
return
# Decode the options
options = L2CAP_Control_Frame.decode_configuration_options(request.options)
for option in options:
if option[0] == L2CAP_MTU_CONFIGURATION_PARAMETER_TYPE:
self.peer_mtu = struct.unpack('<H', option[1])[0]
logger.debug(f'peer MTU = {self.peer_mtu}')
self.send_control_frame(
L2CAP_Configure_Response(
identifier=request.identifier,
source_cid=self.destination_cid,
flags=0x0000,
result=L2CAP_Configure_Response.Result.SUCCESS,
options=request.options, # TODO: don't accept everything blindly
)
)
if self.state == self.State.WAIT_CONFIG:
self._change_state(self.State.WAIT_SEND_CONFIG)
self.send_configure_request()
self._change_state(self.State.WAIT_CONFIG_RSP)
elif self.state == self.State.WAIT_CONFIG_REQ:
self._change_state(self.State.OPEN)
if self.connection_result:
self.connection_result.set_result(None)
self.connection_result = None
self.emit(self.EVENT_OPEN)
elif self.state == self.State.WAIT_CONFIG_REQ_RSP:
self._change_state(self.State.WAIT_CONFIG_RSP)
def on_configure_response(self, response: L2CAP_Configure_Response) -> None:
if response.result == L2CAP_Configure_Response.Result.SUCCESS:
if self.state == self.State.WAIT_CONFIG_REQ_RSP:
self._change_state(self.State.WAIT_CONFIG_REQ)
elif self.state in (
self.State.WAIT_CONFIG_RSP,
self.State.WAIT_CONTROL_IND,
):
self._change_state(self.State.OPEN)
if self.connection_result:
self.connection_result.set_result(None)
self.connection_result = None
self.emit(self.EVENT_OPEN)
else:
logger.warning(color('invalid state', 'red'))
elif (
response.result
== L2CAP_Configure_Response.Result.FAILURE_UNACCEPTABLE_PARAMETERS
):
# Re-configure with what's suggested in the response
self.send_control_frame(
L2CAP_Configure_Request(
identifier=self.manager.next_identifier(self.connection),
destination_cid=self.destination_cid,
flags=0x0000,
options=response.options,
)
)
else:
logger.warning(
color(
'!!! configuration rejected: '
f'{L2CAP_Configure_Response.Result(response.result).name}',
'red',
)
)
# TODO: decide how to fail gracefully
def on_disconnection_request(self, request: L2CAP_Disconnection_Request) -> None:
if self.state in (self.State.OPEN, self.State.WAIT_DISCONNECT):
self.send_control_frame(
L2CAP_Disconnection_Response(
identifier=request.identifier,
destination_cid=request.destination_cid,
source_cid=request.source_cid,
)
)
self._change_state(self.State.CLOSED)
self.emit(self.EVENT_CLOSE)
self.manager.on_channel_closed(self)
else:
logger.warning(color('invalid state', 'red'))
def on_disconnection_response(self, response: L2CAP_Disconnection_Response) -> None:
if self.state != self.State.WAIT_DISCONNECT:
logger.warning(color('invalid state', 'red'))
return
if (
response.destination_cid != self.destination_cid
or response.source_cid != self.source_cid
):
logger.warning('unexpected source or destination CID')
return
self._change_state(self.State.CLOSED)
if self.disconnection_result:
self.disconnection_result.set_result(None)
self.disconnection_result = None
self.emit(self.EVENT_CLOSE)
self.manager.on_channel_closed(self)
def __str__(self) -> str:
return (
f'Channel({self.source_cid}->{self.destination_cid}, '
f'PSM={self.psm}, '
f'MTU={self.mtu}/{self.peer_mtu}, '
f'state={self.state.name})'
)
# -----------------------------------------------------------------------------
class LeCreditBasedChannel(utils.EventEmitter):
"""
LE Credit-based Connection Oriented Channel
"""
class State(enum.IntEnum):
INIT = 0
CONNECTED = 1
CONNECTING = 2
DISCONNECTING = 3
DISCONNECTED = 4
CONNECTION_ERROR = 5
out_queue: deque[bytes]
connection_result: Optional[asyncio.Future[LeCreditBasedChannel]]
disconnection_result: Optional[asyncio.Future[None]]
in_sdu: Optional[bytes]
out_sdu: Optional[bytes]
state: State
connection: Connection
sink: Optional[Callable[[bytes], Any]]
EVENT_OPEN = "open"
EVENT_CLOSE = "close"
def __init__(
self,
manager: ChannelManager,
connection: Connection,
le_psm: int,
source_cid: int,
destination_cid: int,
mtu: int,
mps: int,
credits: int, # pylint: disable=redefined-builtin
peer_mtu: int,
peer_mps: int,
peer_credits: int,
connected: bool,
) -> None:
super().__init__()
self.manager = manager
self.connection = connection
self.le_psm = le_psm
self.source_cid = source_cid
self.destination_cid = destination_cid
self.mtu = mtu
self.mps = mps
self.credits = credits
self.peer_mtu = peer_mtu
self.peer_mps = peer_mps
self.peer_credits = peer_credits
self.peer_max_credits = self.peer_credits
self.peer_credits_threshold = self.peer_max_credits // 2
self.in_sdu = None
self.in_sdu_length = 0
self.out_queue = deque()
self.out_sdu = None
self.sink = None
self.connected = False
self.connection_result = None
self.disconnection_result = None
self.drained = asyncio.Event()
self.drained.set()
if connected:
self.state = self.State.CONNECTED
else:
self.state = self.State.INIT
def _change_state(self, new_state: State) -> None:
logger.debug(f'{self} state change -> {color(new_state.name, "cyan")}')
self.state = new_state
if new_state == self.State.CONNECTED:
self.emit(self.EVENT_OPEN)
elif new_state == self.State.DISCONNECTED:
self.emit(self.EVENT_CLOSE)
def send_pdu(self, pdu: Union[SupportsBytes, bytes]) -> None:
self.manager.send_pdu(self.connection, self.destination_cid, pdu)
def send_control_frame(self, frame: L2CAP_Control_Frame) -> None:
self.manager.send_control_frame(self.connection, L2CAP_LE_SIGNALING_CID, frame)
async def connect(self) -> LeCreditBasedChannel:
# Check that we're in the right state
if self.state != self.State.INIT:
raise InvalidStateError('not in a connectable state')
# Check that we can start a new connection
identifier = self.manager.next_identifier(self.connection)
if identifier in self.manager.le_coc_requests:
raise InvalidStateError('too many concurrent connection requests')
self._change_state(self.State.CONNECTING)
request = L2CAP_LE_Credit_Based_Connection_Request(
identifier=identifier,
le_psm=self.le_psm,
source_cid=self.source_cid,
mtu=self.mtu,
mps=self.mps,
initial_credits=self.peer_credits,
)
self.manager.le_coc_requests[identifier] = request
self.send_control_frame(request)
# Create a future to wait for the response
self.connection_result = asyncio.get_running_loop().create_future()
# Wait for the connection to succeed or fail
return await self.connection_result
async def disconnect(self) -> None:
# Check that we're connected
if self.state != self.State.CONNECTED:
raise InvalidStateError('not connected')
self._change_state(self.State.DISCONNECTING)
self.flush_output()
self.send_control_frame(
L2CAP_Disconnection_Request(
identifier=self.manager.next_identifier(self.connection),
destination_cid=self.destination_cid,
source_cid=self.source_cid,
)
)
# Create a future to wait for the state machine to get to a success or error
# state
self.disconnection_result = asyncio.get_running_loop().create_future()
return await self.disconnection_result
def abort(self) -> None:
if self.state == self.State.CONNECTED:
self._change_state(self.State.DISCONNECTED)
def on_pdu(self, pdu: bytes) -> None:
if self.sink is None:
logger.warning('received pdu without a sink')
return
if self.state != self.State.CONNECTED:
logger.warning('received PDU while not connected, dropping')
# Manage the peer credits
if self.peer_credits == 0:
logger.warning('received LE frame when peer out of credits')
else:
self.peer_credits -= 1
if self.peer_credits <= self.peer_credits_threshold:
# The credits fell below the threshold, replenish them to the max
self.send_control_frame(
L2CAP_LE_Flow_Control_Credit(
identifier=self.manager.next_identifier(self.connection),
cid=self.source_cid,
credits=self.peer_max_credits - self.peer_credits,
)
)
self.peer_credits = self.peer_max_credits
# Check if this starts a new SDU
if self.in_sdu is None:
# Start a new SDU
self.in_sdu = pdu
else:
# Continue an SDU
self.in_sdu += pdu
# Check if the SDU is complete
if self.in_sdu_length == 0:
# We don't know the size yet, check if we have received the header to
# compute it
if len(self.in_sdu) >= 2:
self.in_sdu_length = struct.unpack_from('<H', self.in_sdu, 0)[0]
if self.in_sdu_length == 0:
# We'll compute it later
return
if len(self.in_sdu) < 2 + self.in_sdu_length:
# Not complete yet
logger.debug(
f'SDU: {len(self.in_sdu) - 2} of {self.in_sdu_length} bytes received'
)
return
if len(self.in_sdu) != 2 + self.in_sdu_length:
# Overflow
logger.warning(
f'SDU overflow: sdu_length={self.in_sdu_length}, '
f'received {len(self.in_sdu) - 2}'
)
# TODO: we should disconnect
self.in_sdu = None
self.in_sdu_length = 0
return
# Send the SDU to the sink
logger.debug(f'SDU complete: 2+{len(self.in_sdu) - 2} bytes')
self.sink(self.in_sdu[2:]) # pylint: disable=not-callable
# Prepare for a new SDU
self.in_sdu = None
self.in_sdu_length = 0
def on_connection_response(
self, response: L2CAP_LE_Credit_Based_Connection_Response
) -> None:
# Look for a matching pending response result
if self.connection_result is None:
logger.warning(
f'received unexpected connection response (id={response.identifier})'
)
return
if (
response.result
== L2CAP_LE_Credit_Based_Connection_Response.Result.CONNECTION_SUCCESSFUL
):
self.destination_cid = response.destination_cid
self.peer_mtu = response.mtu
self.peer_mps = response.mps
self.credits = response.initial_credits
self.connected = True
self.connection_result.set_result(self)
self._change_state(self.State.CONNECTED)
else:
self.connection_result.set_exception(
ProtocolError(
response.result,
'l2cap',
L2CAP_LE_Credit_Based_Connection_Response.Result(
response.result
).name,
)
)
self._change_state(self.State.CONNECTION_ERROR)
# Cleanup
self.connection_result = None
def on_credits(self, credits: int) -> None: # pylint: disable=redefined-builtin
self.credits += credits
logger.debug(f'received {credits} credits, total = {self.credits}')
# Try to send more data if we have any queued up
self.process_output()
def on_disconnection_request(self, request: L2CAP_Disconnection_Request) -> None:
self.send_control_frame(
L2CAP_Disconnection_Response(
identifier=request.identifier,
destination_cid=request.destination_cid,
source_cid=request.source_cid,
)
)
self._change_state(self.State.DISCONNECTED)
self.flush_output()
def on_disconnection_response(self, response: L2CAP_Disconnection_Response) -> None:
if self.state != self.State.DISCONNECTING:
logger.warning(color('invalid state', 'red'))
return
if (
response.destination_cid != self.destination_cid
or response.source_cid != self.source_cid
):
logger.warning('unexpected source or destination CID')
return
self._change_state(self.State.DISCONNECTED)
if self.disconnection_result:
self.disconnection_result.set_result(None)
self.disconnection_result = None
def flush_output(self) -> None:
self.out_queue.clear()
self.out_sdu = None
def process_output(self) -> None:
while self.credits > 0:
if self.out_sdu is not None:
# Finish the current SDU
packet = self.out_sdu[: self.peer_mps]
self.send_pdu(packet)
self.credits -= 1
logger.debug(f'sent {len(packet)} bytes, {self.credits} credits left')
if len(packet) == len(self.out_sdu):
# We sent everything
self.out_sdu = None
else:
# Keep what's still left to send
self.out_sdu = self.out_sdu[len(packet) :]
continue
if self.out_queue:
# Create the next SDU (2 bytes header plus up to MTU bytes payload)
logger.debug(
f'assembling SDU from {len(self.out_queue)} packets in output queue'
)
payload = b''
while self.out_queue and len(payload) < self.peer_mtu:
# We can add more data to the payload
chunk = self.out_queue[0][: self.peer_mtu - len(payload)]
payload += chunk
self.out_queue[0] = self.out_queue[0][len(chunk) :]
if len(self.out_queue[0]) == 0:
# We consumed the entire buffer, remove it
self.out_queue.popleft()
logger.debug(
f'packet completed, {len(self.out_queue)} left in queue'
)
# Construct the SDU with its header
assert len(payload) != 0
logger.debug(f'SDU complete: {len(payload)} payload bytes')
self.out_sdu = struct.pack('<H', len(payload)) + payload
else:
# Nothing left to send for now
self.drained.set()
return
def write(self, data: bytes) -> None:
if self.state != self.State.CONNECTED:
logger.warning('not connected, dropping data')
return
# Queue the data
self.out_queue.append(data)
self.drained.clear()
logger.debug(
f'{len(data)} bytes packet queued, {len(self.out_queue)} packets in queue'
)
# Send what we can
self.process_output()
async def drain(self) -> None:
await self.drained.wait()
def pause_reading(self) -> None:
# TODO: not implemented yet
pass
def resume_reading(self) -> None:
# TODO: not implemented yet
pass
def __str__(self) -> str:
return (
f'CoC({self.source_cid}->{self.destination_cid}, '
f'State={self.state.name}, '
f'PSM={self.le_psm}, '
f'MTU={self.mtu}/{self.peer_mtu}, '
f'MPS={self.mps}/{self.peer_mps}, '
f'credits={self.credits}/{self.peer_credits})'
)
# -----------------------------------------------------------------------------
class ClassicChannelServer(utils.EventEmitter):
EVENT_CONNECTION = "connection"
def __init__(
self,
manager: ChannelManager,
psm: int,
handler: Optional[Callable[[ClassicChannel], Any]],
mtu: int,
) -> None:
super().__init__()
self.manager = manager
self.handler = handler
self.psm = psm
self.mtu = mtu
def on_connection(self, channel: ClassicChannel) -> None:
self.emit(self.EVENT_CONNECTION, channel)
if self.handler:
self.handler(channel)
def close(self) -> None:
if self.psm in self.manager.servers:
del self.manager.servers[self.psm]
# -----------------------------------------------------------------------------
class LeCreditBasedChannelServer(utils.EventEmitter):
EVENT_CONNECTION = "connection"
def __init__(
self,
manager: ChannelManager,
psm: int,
handler: Optional[Callable[[LeCreditBasedChannel], Any]],
max_credits: int,
mtu: int,
mps: int,
) -> None:
super().__init__()
self.manager = manager
self.handler = handler
self.psm = psm
self.max_credits = max_credits
self.mtu = mtu
self.mps = mps
def on_connection(self, channel: LeCreditBasedChannel) -> None:
self.emit(self.EVENT_CONNECTION, channel)
if self.handler:
self.handler(channel)
def close(self) -> None:
if self.psm in self.manager.le_coc_servers:
del self.manager.le_coc_servers[self.psm]
# -----------------------------------------------------------------------------
class ChannelManager:
identifiers: dict[int, int]
channels: dict[int, dict[int, Union[ClassicChannel, LeCreditBasedChannel]]]
servers: dict[int, ClassicChannelServer]
le_coc_channels: dict[int, dict[int, LeCreditBasedChannel]]
le_coc_servers: dict[int, LeCreditBasedChannelServer]
le_coc_requests: dict[int, L2CAP_LE_Credit_Based_Connection_Request]
fixed_channels: dict[int, Optional[Callable[[int, bytes], Any]]]
_host: Optional[Host]
connection_parameters_update_response: Optional[asyncio.Future[int]]
def __init__(
self,
extended_features: Iterable[int] = (),
connectionless_mtu: int = L2CAP_DEFAULT_CONNECTIONLESS_MTU,
) -> None:
self._host = None
self.identifiers = {} # Incrementing identifier values by connection
self.channels = {} # All channels, mapped by connection and source cid
self.fixed_channels = { # Fixed channel handlers, mapped by cid
L2CAP_SIGNALING_CID: None,
L2CAP_LE_SIGNALING_CID: None,
}
self.servers = {} # Servers accepting connections, by PSM
self.le_coc_channels = (
{}
) # LE CoC channels, mapped by connection and destination cid
self.le_coc_servers = {} # LE CoC - Servers accepting connections, by PSM
self.le_coc_requests = {} # LE CoC connection requests, by identifier
self.extended_features = extended_features
self.connectionless_mtu = connectionless_mtu
self.connection_parameters_update_response = None
@property
def host(self) -> Host:
assert self._host
return self._host
@host.setter
def host(self, host: Host) -> None:
if self._host is not None:
self._host.remove_listener('disconnection', self.on_disconnection)
self._host = host
if host is not None:
host.on('disconnection', self.on_disconnection)
def find_channel(self, connection_handle: int, cid: int):
if connection_channels := self.channels.get(connection_handle):
return connection_channels.get(cid)
return None
def find_le_coc_channel(self, connection_handle: int, cid: int):
if connection_channels := self.le_coc_channels.get(connection_handle):
return connection_channels.get(cid)
return None
@staticmethod
def find_free_br_edr_cid(channels: Iterable[int]) -> int:
# Pick the smallest valid CID that's not already in the list
# (not necessarily the most efficient algorithm, but the list of CID is
# very small in practice)
for cid in range(
L2CAP_ACL_U_DYNAMIC_CID_RANGE_START, L2CAP_ACL_U_DYNAMIC_CID_RANGE_END + 1
):
if cid not in channels:
return cid
raise OutOfResourcesError('no free CID available')
@staticmethod
def find_free_le_cid(channels: Iterable[int]) -> int:
# Pick the smallest valid CID that's not already in the list
# (not necessarily the most efficient algorithm, but the list of CID is
# very small in practice)
for cid in range(
L2CAP_LE_U_DYNAMIC_CID_RANGE_START, L2CAP_LE_U_DYNAMIC_CID_RANGE_END + 1
):
if cid not in channels:
return cid
raise OutOfResourcesError('no free CID')
def next_identifier(self, connection: Connection) -> int:
identifier = (self.identifiers.setdefault(connection.handle, 0) + 1) % 256
# 0x00 is an invalid ID (BT Core Spec, Vol 3, Part A, Sect 4
if identifier == 0:
identifier = 1
self.identifiers[connection.handle] = identifier
return identifier
def register_fixed_channel(
self, cid: int, handler: Callable[[int, bytes], Any]
) -> None:
self.fixed_channels[cid] = handler
def deregister_fixed_channel(self, cid: int) -> None:
if cid in self.fixed_channels:
del self.fixed_channels[cid]
def create_classic_server(
self,
spec: ClassicChannelSpec,
handler: Optional[Callable[[ClassicChannel], Any]] = None,
) -> ClassicChannelServer:
if not spec.psm:
# Find a free PSM
for candidate in range(
L2CAP_PSM_DYNAMIC_RANGE_START, L2CAP_PSM_DYNAMIC_RANGE_END + 1, 2
):
if (candidate >> 8) % 2 == 1:
continue
if candidate in self.servers:
continue
spec.psm = candidate
break
else:
raise InvalidStateError('no free PSM')
else:
# Check that the PSM isn't already in use
if spec.psm in self.servers:
raise InvalidArgumentError('PSM already in use')
# Check that the PSM is valid
if spec.psm % 2 == 0:
raise InvalidArgumentError('invalid PSM (not odd)')
check = spec.psm >> 8
while check:
if check % 2 != 0:
raise InvalidArgumentError('invalid PSM')
check >>= 8
self.servers[spec.psm] = ClassicChannelServer(self, spec.psm, handler, spec.mtu)
return self.servers[spec.psm]
def create_le_credit_based_server(
self,
spec: LeCreditBasedChannelSpec,
handler: Optional[Callable[[LeCreditBasedChannel], Any]] = None,
) -> LeCreditBasedChannelServer:
if not spec.psm:
# Find a free PSM
for candidate in range(
L2CAP_LE_PSM_DYNAMIC_RANGE_START, L2CAP_LE_PSM_DYNAMIC_RANGE_END + 1
):
if candidate in self.le_coc_servers:
continue
spec.psm = candidate
break
else:
raise InvalidStateError('no free PSM')
else:
# Check that the PSM isn't already in use
if spec.psm in self.le_coc_servers:
raise InvalidArgumentError('PSM already in use')
self.le_coc_servers[spec.psm] = LeCreditBasedChannelServer(
self,
spec.psm,
handler,
max_credits=spec.max_credits,
mtu=spec.mtu,
mps=spec.mps,
)
return self.le_coc_servers[spec.psm]
def on_disconnection(self, connection_handle: int, _reason: int) -> None:
logger.debug(f'disconnection from {connection_handle}, cleaning up channels')
if connection_handle in self.channels:
for _, channel in self.channels[connection_handle].items():
channel.abort()
del self.channels[connection_handle]
if connection_handle in self.le_coc_channels:
for _, channel in self.le_coc_channels[connection_handle].items():
channel.abort()
del self.le_coc_channels[connection_handle]
if connection_handle in self.identifiers:
del self.identifiers[connection_handle]
def send_pdu(self, connection, cid: int, pdu: Union[SupportsBytes, bytes]) -> None:
pdu_str = pdu.hex() if isinstance(pdu, bytes) else str(pdu)
pdu_bytes = bytes(pdu)
logger.debug(
f'{color(">>> Sending L2CAP PDU", "blue")} '
f'on connection [0x{connection.handle:04X}] (CID={cid}) '
f'{connection.peer_address}: {len(pdu_bytes)} bytes, {pdu_str}'
)
self.host.send_l2cap_pdu(connection.handle, cid, pdu_bytes)
def on_pdu(self, connection: Connection, cid: int, pdu: bytes) -> None:
if cid in (L2CAP_SIGNALING_CID, L2CAP_LE_SIGNALING_CID):
# Parse the L2CAP payload into a Control Frame object
control_frame = L2CAP_Control_Frame.from_bytes(pdu)
self.on_control_frame(connection, cid, control_frame)
elif cid in self.fixed_channels:
handler = self.fixed_channels[cid]
assert handler is not None
handler(connection.handle, pdu)
else:
if (channel := self.find_channel(connection.handle, cid)) is None:
logger.warning(
color(
f'channel not found for 0x{connection.handle:04X}:{cid}', 'red'
)
)
return
channel.on_pdu(pdu)
def send_control_frame(
self, connection: Connection, cid: int, control_frame: L2CAP_Control_Frame
) -> None:
logger.debug(
f'{color(">>> Sending L2CAP Signaling Control Frame", "blue")} '
f'on connection [0x{connection.handle:04X}] (CID={cid}) '
f'{connection.peer_address}:\n{control_frame}'
)
self.host.send_l2cap_pdu(connection.handle, cid, bytes(control_frame))
def on_control_frame(
self, connection: Connection, cid: int, control_frame: L2CAP_Control_Frame
) -> None:
logger.debug(
f'{color("<<< Received L2CAP Signaling Control Frame", "green")} '
f'on connection [0x{connection.handle:04X}] (CID={cid}) '
f'{connection.peer_address}:\n{control_frame}'
)
# Find the handler method
handler_name = f'on_{control_frame.name.lower()}'
handler = getattr(self, handler_name, None)
if handler:
try:
handler(connection, cid, control_frame)
except Exception:
logger.exception(color("!!! Exception in handler:", "red"))
self.send_control_frame(
connection,
cid,
L2CAP_Command_Reject(
identifier=control_frame.identifier,
reason=L2CAP_COMMAND_NOT_UNDERSTOOD_REASON,
data=b'',
),
)
raise
else:
logger.error(color('Channel Manager command not handled???', 'red'))
self.send_control_frame(
connection,
cid,
L2CAP_Command_Reject(
identifier=control_frame.identifier,
reason=L2CAP_COMMAND_NOT_UNDERSTOOD_REASON,
data=b'',
),
)
def on_l2cap_command_reject(
self, _connection: Connection, _cid: int, packet: L2CAP_Command_Reject
) -> None:
logger.warning(f'{color("!!! Command rejected:", "red")} {packet.reason}')
def on_l2cap_connection_request(
self, connection: Connection, cid: int, request: L2CAP_Connection_Request
) -> None:
# Check if there's a server for this PSM
server = self.servers.get(request.psm)
if server:
# Find a free CID for this new channel
connection_channels = self.channels.setdefault(connection.handle, {})
source_cid = self.find_free_br_edr_cid(connection_channels)
if source_cid is None: # Should never happen!
self.send_control_frame(
connection,
cid,
L2CAP_Connection_Response(
identifier=request.identifier,
destination_cid=request.source_cid,
source_cid=0,
# pylint: disable=line-too-long
result=L2CAP_Connection_Response.Result.CONNECTION_REFUSED_NO_RESOURCES_AVAILABLE,
status=0x0000,
),
)
return
# Create a new channel
logger.debug(
f'creating server channel with cid={source_cid} for psm {request.psm}'
)
channel = ClassicChannel(
self, connection, cid, request.psm, source_cid, server.mtu
)
connection_channels[source_cid] = channel
# Notify
server.on_connection(channel)
channel.on_connection_request(request)
else:
logger.warning(
f'No server for connection 0x{connection.handle:04X} '
f'on PSM {request.psm}'
)
self.send_control_frame(
connection,
cid,
L2CAP_Connection_Response(
identifier=request.identifier,
destination_cid=request.source_cid,
source_cid=0,
# pylint: disable=line-too-long
result=L2CAP_Connection_Response.Result.CONNECTION_REFUSED_PSM_NOT_SUPPORTED,
status=0x0000,
),
)
def on_l2cap_connection_response(
self,
connection: Connection,
cid: int,
response: L2CAP_Connection_Response,
) -> None:
if (
channel := self.find_channel(connection.handle, response.source_cid)
) is None:
logger.warning(
color(
f'channel {response.source_cid} not found for '
f'0x{connection.handle:04X}:{cid}',
'red',
)
)
return
channel.on_connection_response(response)
def on_l2cap_configure_request(
self, connection: Connection, cid: int, request: L2CAP_Configure_Request
) -> None:
if (
channel := self.find_channel(connection.handle, request.destination_cid)
) is None:
logger.warning(
color(
f'channel {request.destination_cid} not found for '
f'0x{connection.handle:04X}:{cid}',
'red',
)
)
return
channel.on_configure_request(request)
def on_l2cap_configure_response(
self, connection: Connection, cid: int, response: L2CAP_Configure_Response
) -> None:
if (
channel := self.find_channel(connection.handle, response.source_cid)
) is None:
logger.warning(
color(
f'channel {response.source_cid} not found for '
f'0x{connection.handle:04X}:{cid}',
'red',
)
)
return
channel.on_configure_response(response)
def on_l2cap_disconnection_request(
self, connection: Connection, cid: int, request: L2CAP_Disconnection_Request
) -> None:
if (
channel := self.find_channel(connection.handle, request.destination_cid)
) is None:
logger.warning(
color(
f'channel {request.destination_cid} not found for '
f'0x{connection.handle:04X}:{cid}',
'red',
)
)
return
channel.on_disconnection_request(request)
def on_l2cap_disconnection_response(
self, connection: Connection, cid: int, response: L2CAP_Disconnection_Response
) -> None:
if (
channel := self.find_channel(connection.handle, response.source_cid)
) is None:
logger.warning(
color(
f'channel {response.source_cid} not found for '
f'0x{connection.handle:04X}:{cid}',
'red',
)
)
return
channel.on_disconnection_response(response)
def on_l2cap_echo_request(
self, connection: Connection, cid: int, request: L2CAP_Echo_Request
) -> None:
logger.debug(f'<<< Echo request: data={request.data.hex()}')
self.send_control_frame(
connection,
cid,
L2CAP_Echo_Response(identifier=request.identifier, data=request.data),
)
def on_l2cap_echo_response(
self, _connection: Connection, _cid: int, response: L2CAP_Echo_Response
) -> None:
logger.debug(f'<<< Echo response: data={response.data.hex()}')
# TODO notify listeners
def on_l2cap_information_request(
self, connection: Connection, cid: int, request: L2CAP_Information_Request
) -> None:
if request.info_type == L2CAP_Information_Request.InfoType.CONNECTIONLESS_MTU:
result = L2CAP_Information_Response.Result.SUCCESS
data = self.connectionless_mtu.to_bytes(2, 'little')
elif (
request.info_type
== L2CAP_Information_Request.InfoType.EXTENDED_FEATURES_SUPPORTED
):
result = L2CAP_Information_Response.Result.SUCCESS
data = sum(self.extended_features).to_bytes(4, 'little')
elif (
request.info_type
== L2CAP_Information_Request.InfoType.FIXED_CHANNELS_SUPPORTED
):
result = L2CAP_Information_Response.Result.SUCCESS
data = sum(1 << cid for cid in self.fixed_channels).to_bytes(8, 'little')
else:
result = L2CAP_Information_Response.Result.NOT_SUPPORTED
data = b''
self.send_control_frame(
connection,
cid,
L2CAP_Information_Response(
identifier=request.identifier,
info_type=request.info_type,
result=result,
data=data,
),
)
def on_l2cap_connection_parameter_update_request(
self,
connection: Connection,
cid: int,
request: L2CAP_Connection_Parameter_Update_Request,
):
if connection.role == hci.Role.CENTRAL:
self.send_control_frame(
connection,
cid,
L2CAP_Connection_Parameter_Update_Response(
identifier=request.identifier,
result=L2CAP_CONNECTION_PARAMETERS_ACCEPTED_RESULT,
),
)
self.host.send_command_sync(
hci.HCI_LE_Connection_Update_Command(
connection_handle=connection.handle,
connection_interval_min=request.interval_min,
connection_interval_max=request.interval_max,
max_latency=request.latency,
supervision_timeout=request.timeout,
min_ce_length=0,
max_ce_length=0,
)
)
else:
self.send_control_frame(
connection,
cid,
L2CAP_Connection_Parameter_Update_Response(
identifier=request.identifier,
result=L2CAP_CONNECTION_PARAMETERS_REJECTED_RESULT,
),
)
async def update_connection_parameters(
self,
connection: Connection,
interval_min: int,
interval_max: int,
latency: int,
timeout: int,
) -> int:
# Check that there isn't already a request pending
if self.connection_parameters_update_response:
raise InvalidStateError('request already pending')
self.connection_parameters_update_response = (
asyncio.get_running_loop().create_future()
)
self.send_control_frame(
connection,
L2CAP_LE_SIGNALING_CID,
L2CAP_Connection_Parameter_Update_Request(
identifier=self.next_identifier(connection),
interval_min=interval_min,
interval_max=interval_max,
latency=latency,
timeout=timeout,
),
)
return await self.connection_parameters_update_response
def on_l2cap_connection_parameter_update_response(
self,
connection: Connection,
cid: int,
response: L2CAP_Connection_Parameter_Update_Response,
) -> None:
if self.connection_parameters_update_response:
self.connection_parameters_update_response.set_result(response.result)
self.connection_parameters_update_response = None
else:
logger.warning(
color(
'received l2cap_connection_parameter_update_response without a pending request',
'red',
)
)
def on_l2cap_le_credit_based_connection_request(
self,
connection: Connection,
cid: int,
request: L2CAP_LE_Credit_Based_Connection_Request,
) -> None:
if request.le_psm in self.le_coc_servers:
server = self.le_coc_servers[request.le_psm]
# Check that the CID isn't already used
le_connection_channels = self.le_coc_channels.setdefault(
connection.handle, {}
)
if request.source_cid in le_connection_channels:
logger.warning(f'source CID {request.source_cid} already in use')
self.send_control_frame(
connection,
cid,
L2CAP_LE_Credit_Based_Connection_Response(
identifier=request.identifier,
destination_cid=0,
mtu=server.mtu,
mps=server.mps,
initial_credits=0,
# pylint: disable=line-too-long
result=L2CAP_LE_Credit_Based_Connection_Response.Result.CONNECTION_REFUSED_SOURCE_CID_ALREADY_ALLOCATED,
),
)
return
# Find a free CID for this new channel
connection_channels = self.channels.setdefault(connection.handle, {})
source_cid = self.find_free_le_cid(connection_channels)
if source_cid is None: # Should never happen!
self.send_control_frame(
connection,
cid,
L2CAP_LE_Credit_Based_Connection_Response(
identifier=request.identifier,
destination_cid=0,
mtu=server.mtu,
mps=server.mps,
initial_credits=0,
# pylint: disable=line-too-long
result=L2CAP_LE_Credit_Based_Connection_Response.Result.CONNECTION_REFUSED_NO_RESOURCES_AVAILABLE,
),
)
return
# Create a new channel
logger.debug(
f'creating LE CoC server channel with cid={source_cid} for psm '
f'{request.le_psm}'
)
channel = LeCreditBasedChannel(
self,
connection,
request.le_psm,
source_cid,
request.source_cid,
server.mtu,
server.mps,
request.initial_credits,
request.mtu,
request.mps,
server.max_credits,
True,
)
connection_channels[source_cid] = channel
le_connection_channels[request.source_cid] = channel
# Respond
self.send_control_frame(
connection,
cid,
L2CAP_LE_Credit_Based_Connection_Response(
identifier=request.identifier,
destination_cid=source_cid,
mtu=server.mtu,
mps=server.mps,
initial_credits=server.max_credits,
# pylint: disable=line-too-long
result=L2CAP_LE_Credit_Based_Connection_Response.Result.CONNECTION_SUCCESSFUL,
),
)
# Notify
server.on_connection(channel)
else:
logger.info(
f'No LE server for connection 0x{connection.handle:04X} '
f'on PSM {request.le_psm}'
)
self.send_control_frame(
connection,
cid,
L2CAP_LE_Credit_Based_Connection_Response(
identifier=request.identifier,
destination_cid=0,
mtu=L2CAP_LE_CREDIT_BASED_CONNECTION_DEFAULT_MTU,
mps=L2CAP_LE_CREDIT_BASED_CONNECTION_DEFAULT_MPS,
initial_credits=0,
# pylint: disable=line-too-long
result=L2CAP_LE_Credit_Based_Connection_Response.Result.CONNECTION_REFUSED_LE_PSM_NOT_SUPPORTED,
),
)
def on_l2cap_le_credit_based_connection_response(
self,
connection: Connection,
_cid: int,
response: L2CAP_LE_Credit_Based_Connection_Response,
) -> None:
# Find the pending request by identifier
request = self.le_coc_requests.get(response.identifier)
if request is None:
logger.warning(color('!!! received response for unknown request', 'red'))
return
del self.le_coc_requests[response.identifier]
# Find the channel for this request
channel = self.find_channel(connection.handle, request.source_cid)
if channel is None:
logger.warning(
color(
'received connection response for an unknown channel '
f'(cid={request.source_cid})',
'red',
)
)
return
# Process the response
channel.on_connection_response(response)
def on_l2cap_le_flow_control_credit(
self, connection: Connection, _cid: int, credit: L2CAP_LE_Flow_Control_Credit
) -> None:
channel = self.find_le_coc_channel(connection.handle, credit.cid)
if channel is None:
logger.warning(f'received credits for an unknown channel (cid={credit.cid}')
return
channel.on_credits(credit.credits)
def on_channel_closed(self, channel: ClassicChannel) -> None:
connection_channels = self.channels.get(channel.connection.handle)
if connection_channels:
if channel.source_cid in connection_channels:
del connection_channels[channel.source_cid]
async def create_le_credit_based_channel(
self,
connection: Connection,
spec: LeCreditBasedChannelSpec,
) -> LeCreditBasedChannel:
# Find a free CID for the new channel
connection_channels = self.channels.setdefault(connection.handle, {})
source_cid = self.find_free_le_cid(connection_channels)
if source_cid is None: # Should never happen!
raise OutOfResourcesError('all CIDs already in use')
if spec.psm is None:
raise InvalidArgumentError('PSM cannot be None')
# Create the channel
logger.debug(f'creating coc channel with cid={source_cid} for psm {spec.psm}')
channel = LeCreditBasedChannel(
manager=self,
connection=connection,
le_psm=spec.psm,
source_cid=source_cid,
destination_cid=0,
mtu=spec.mtu,
mps=spec.mps,
credits=0,
peer_mtu=0,
peer_mps=0,
peer_credits=spec.max_credits,
connected=False,
)
connection_channels[source_cid] = channel
# Connect
try:
await channel.connect()
except Exception:
logger.exception('connection failed')
del connection_channels[source_cid]
raise
# Remember the channel by source CID and destination CID
le_connection_channels = self.le_coc_channels.setdefault(connection.handle, {})
le_connection_channels[channel.destination_cid] = channel
return channel
async def create_classic_channel(
self, connection: Connection, spec: ClassicChannelSpec
) -> ClassicChannel:
# NOTE: this implementation hard-codes BR/EDR
# Find a free CID for a new channel
connection_channels = self.channels.setdefault(connection.handle, {})
source_cid = self.find_free_br_edr_cid(connection_channels)
if source_cid is None: # Should never happen!
raise OutOfResourcesError('all CIDs already in use')
if spec.psm is None:
raise InvalidArgumentError('PSM cannot be None')
# Create the channel
logger.debug(
f'creating client channel with cid={source_cid} for psm {spec.psm}'
)
channel = ClassicChannel(
self,
connection,
L2CAP_SIGNALING_CID,
spec.psm,
source_cid,
spec.mtu,
)
connection_channels[source_cid] = channel
# Connect
try:
await channel.connect()
except BaseException as e:
del connection_channels[source_cid]
raise e
return channel
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