# 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 # ----------------------------------------------------------------------------- import logging import struct from colors import color import colors from . import core from .core import InvalidStateError from .hci import HCI_Object, name_or_number, key_with_value # ----------------------------------------------------------------------------- # Logging # ----------------------------------------------------------------------------- logger = logging.getLogger(__name__) # ----------------------------------------------------------------------------- # Constants # ----------------------------------------------------------------------------- SDP_CONTINUATION_WATCHDOG = 64 # Maximum number of continuations we're willing to do SDP_PSM = 0x0001 SDP_ERROR_RESPONSE = 0x01 SDP_SERVICE_SEARCH_REQUEST = 0x02 SDP_SERVICE_SEARCH_RESPONSE = 0x03 SDP_SERVICE_ATTRIBUTE_REQUEST = 0x04 SDP_SERVICE_ATTRIBUTE_RESPONSE = 0x05 SDP_SERVICE_SEARCH_ATTRIBUTE_REQUEST = 0x06 SDP_SERVICE_SEARCH_ATTRIBUTE_RESPONSE = 0x07 SDP_PDU_NAMES = { SDP_ERROR_RESPONSE: 'SDP_ERROR_RESPONSE', SDP_SERVICE_SEARCH_REQUEST: 'SDP_SERVICE_SEARCH_REQUEST', SDP_SERVICE_SEARCH_RESPONSE: 'SDP_SERVICE_SEARCH_RESPONSE', SDP_SERVICE_ATTRIBUTE_REQUEST: 'SDP_SERVICE_ATTRIBUTE_REQUEST', SDP_SERVICE_ATTRIBUTE_RESPONSE: 'SDP_SERVICE_ATTRIBUTE_RESPONSE', SDP_SERVICE_SEARCH_ATTRIBUTE_REQUEST: 'SDP_SERVICE_SEARCH_ATTRIBUTE_REQUEST', SDP_SERVICE_SEARCH_ATTRIBUTE_RESPONSE: 'SDP_SERVICE_SEARCH_ATTRIBUTE_RESPONSE' } SDP_INVALID_SDP_VERSION_ERROR = 0x0001 SDP_INVALID_SERVICE_RECORD_HANDLE_ERROR = 0x0002 SDP_INVALID_REQUEST_SYNTAX_ERROR = 0x0003 SDP_INVALID_PDU_SIZE_ERROR = 0x0004 SDP_INVALID_CONTINUATION_STATE_ERROR = 0x0005 SDP_INSUFFICIENT_RESOURCES_TO_SATISFY_REQUEST_ERROR = 0x0006 SDP_ERROR_NAMES = { SDP_INVALID_SDP_VERSION_ERROR: 'SDP_INVALID_SDP_VERSION_ERROR', SDP_INVALID_SERVICE_RECORD_HANDLE_ERROR: 'SDP_INVALID_SERVICE_RECORD_HANDLE_ERROR', SDP_INVALID_REQUEST_SYNTAX_ERROR: 'SDP_INVALID_REQUEST_SYNTAX_ERROR', SDP_INVALID_PDU_SIZE_ERROR: 'SDP_INVALID_PDU_SIZE_ERROR', SDP_INVALID_CONTINUATION_STATE_ERROR: 'SDP_INVALID_CONTINUATION_STATE_ERROR', SDP_INSUFFICIENT_RESOURCES_TO_SATISFY_REQUEST_ERROR: 'SDP_INSUFFICIENT_RESOURCES_TO_SATISFY_REQUEST_ERROR' } SDP_SERVICE_NAME_ATTRIBUTE_ID_OFFSET = 0x0000 SDP_SERVICE_DESCRIPTION_ATTRIBUTE_ID_OFFSET = 0x0001 SDP_PROVIDER_NAME_ATTRIBUTE_ID_OFFSET = 0x0002 SDP_SERVICE_RECORD_HANDLE_ATTRIBUTE_ID = 0X0000 SDP_SERVICE_CLASS_ID_LIST_ATTRIBUTE_ID = 0X0001 SDP_SERVICE_RECORD_STATE_ATTRIBUTE_ID = 0X0002 SDP_SERVICE_ID_ATTRIBUTE_ID = 0X0003 SDP_PROTOCOL_DESCRIPTOR_LIST_ATTRIBUTE_ID = 0X0004 SDP_BROWSE_GROUP_LIST_ATTRIBUTE_ID = 0X0005 SDP_LANGUAGE_BASE_ATTRIBUTE_ID_LIST_ATTRIBUTE_ID = 0X0006 SDP_SERVICE_INFO_TIME_TO_LIVE_ATTRIBUTE_ID = 0X0007 SDP_SERVICE_AVAILABILITY_ATTRIBUTE_ID = 0X0008 SDP_BLUETOOTH_PROFILE_DESCRIPTOR_LIST_ATTRIBUTE_ID = 0X0009 SDP_DOCUMENTATION_URL_ATTRIBUTE_ID = 0X000A SDP_CLIENT_EXECUTABLE_URL_ATTRIBUTE_ID = 0X000B SDP_ICON_URL_ATTRIBUTE_ID = 0X000C SDP_ADDITIONAL_PROTOCOL_DESCRIPTOR_LIST_ATTRIBUTE_ID = 0X000D SDP_ATTRIBUTE_ID_NAMES = { SDP_SERVICE_RECORD_HANDLE_ATTRIBUTE_ID: 'SDP_SERVICE_RECORD_HANDLE_ATTRIBUTE_ID', SDP_SERVICE_CLASS_ID_LIST_ATTRIBUTE_ID: 'SDP_SERVICE_CLASS_ID_LIST_ATTRIBUTE_ID', SDP_SERVICE_RECORD_STATE_ATTRIBUTE_ID: 'SDP_SERVICE_RECORD_STATE_ATTRIBUTE_ID', SDP_SERVICE_ID_ATTRIBUTE_ID: 'SDP_SERVICE_ID_ATTRIBUTE_ID', SDP_PROTOCOL_DESCRIPTOR_LIST_ATTRIBUTE_ID: 'SDP_PROTOCOL_DESCRIPTOR_LIST_ATTRIBUTE_ID', SDP_BROWSE_GROUP_LIST_ATTRIBUTE_ID: 'SDP_BROWSE_GROUP_LIST_ATTRIBUTE_ID', SDP_LANGUAGE_BASE_ATTRIBUTE_ID_LIST_ATTRIBUTE_ID: 'SDP_LANGUAGE_BASE_ATTRIBUTE_ID_LIST_ATTRIBUTE_ID', SDP_SERVICE_INFO_TIME_TO_LIVE_ATTRIBUTE_ID: 'SDP_SERVICE_INFO_TIME_TO_LIVE_ATTRIBUTE_ID', SDP_SERVICE_AVAILABILITY_ATTRIBUTE_ID: 'SDP_SERVICE_AVAILABILITY_ATTRIBUTE_ID', SDP_BLUETOOTH_PROFILE_DESCRIPTOR_LIST_ATTRIBUTE_ID: 'SDP_BLUETOOTH_PROFILE_DESCRIPTOR_LIST_ATTRIBUTE_ID', SDP_DOCUMENTATION_URL_ATTRIBUTE_ID: 'SDP_DOCUMENTATION_URL_ATTRIBUTE_ID', SDP_CLIENT_EXECUTABLE_URL_ATTRIBUTE_ID: 'SDP_CLIENT_EXECUTABLE_URL_ATTRIBUTE_ID', SDP_ICON_URL_ATTRIBUTE_ID: 'SDP_ICON_URL_ATTRIBUTE_ID', SDP_ADDITIONAL_PROTOCOL_DESCRIPTOR_LIST_ATTRIBUTE_ID: 'SDP_ADDITIONAL_PROTOCOL_DESCRIPTOR_LIST_ATTRIBUTE_ID' } SDP_PUBLIC_BROWSE_ROOT = core.UUID.from_16_bits(0x1002, 'PublicBrowseRoot') # To be used in searches where an attribute ID list allows a range to be specified SDP_ALL_ATTRIBUTES_RANGE = (0x0000FFFF, 4) # Express this as tuple so we can convey the desired encoding size # ----------------------------------------------------------------------------- class DataElement: NIL = 0 UNSIGNED_INTEGER = 1 SIGNED_INTEGER = 2 UUID = 3 TEXT_STRING = 4 BOOLEAN = 5 SEQUENCE = 6 ALTERNATIVE = 7 URL = 8 TYPE_NAMES = { NIL: 'NIL', UNSIGNED_INTEGER: 'UNSIGNED_INTEGER', SIGNED_INTEGER: 'SIGNED_INTEGER', UUID: 'UUID', TEXT_STRING: 'TEXT_STRING', BOOLEAN: 'BOOLEAN', SEQUENCE: 'SEQUENCE', ALTERNATIVE: 'ALTERNATIVE', URL: 'URL' } type_constructors = { NIL: lambda x: DataElement(DataElement.NIL, None), UNSIGNED_INTEGER: lambda x, y: DataElement(DataElement.UNSIGNED_INTEGER, DataElement.unsigned_integer_from_bytes(x), value_size=y), SIGNED_INTEGER: lambda x, y: DataElement(DataElement.SIGNED_INTEGER, DataElement.signed_integer_from_bytes(x), value_size=y), UUID: lambda x: DataElement(DataElement.UUID, core.UUID.from_bytes(bytes(reversed(x)))), TEXT_STRING: lambda x: DataElement(DataElement.TEXT_STRING, x.decode('utf8')), BOOLEAN: lambda x: DataElement(DataElement.BOOLEAN, x[0] == 1), SEQUENCE: lambda x: DataElement(DataElement.SEQUENCE, DataElement.list_from_bytes(x)), ALTERNATIVE: lambda x: DataElement(DataElement.ALTERNATIVE, DataElement.list_from_bytes(x)), URL: lambda x: DataElement(DataElement.URL, x.decode('utf8')) } def __init__(self, type, value, value_size=None): self.type = type self.value = value self.value_size = value_size self.bytes = None # Used a cache when parsing from bytes so we can emit a byte-for-byte replica if type == DataElement.UNSIGNED_INTEGER or type == DataElement.SIGNED_INTEGER: if value_size is None: raise ValueError('integer types must have a value size specified') @staticmethod def nil(): return DataElement(DataElement.NIL, None) @staticmethod def unsigned_integer(value, value_size): return DataElement(DataElement.UNSIGNED_INTEGER, value, value_size) @staticmethod def unsigned_integer_8(value): return DataElement(DataElement.UNSIGNED_INTEGER, value, value_size=1) @staticmethod def unsigned_integer_16(value): return DataElement(DataElement.UNSIGNED_INTEGER, value, value_size=2) @staticmethod def unsigned_integer_32(value): return DataElement(DataElement.UNSIGNED_INTEGER, value, value_size=4) @staticmethod def signed_integer(value, value_size): return DataElement(DataElement.SIGNED_INTEGER, value, value_size) @staticmethod def signed_integer_8(value): return DataElement(DataElement.SIGNED_INTEGER, value, value_size=1) @staticmethod def signed_integer_16(value): return DataElement(DataElement.SIGNED_INTEGER, value, value_size=2) @staticmethod def signed_integer_32(value): return DataElement(DataElement.SIGNED_INTEGER, value, value_size=4) @staticmethod def uuid(value): return DataElement(DataElement.UUID, value) @staticmethod def text_string(value): return DataElement(DataElement.TEXT_STRING, value) @staticmethod def boolean(value): return DataElement(DataElement.BOOLEAN, value) @staticmethod def sequence(value): return DataElement(DataElement.SEQUENCE, value) @staticmethod def alternative(value): return DataElement(DataElement.ALTERNATIVE, value) @staticmethod def url(value): return DataElement(DataElement.URL, value) @staticmethod def unsigned_integer_from_bytes(data): if len(data) == 1: return data[0] elif len(data) == 2: return struct.unpack('>H', data)[0] elif len(data) == 4: return struct.unpack('>I', data)[0] elif len(data) == 8: return struct.unpack('>Q', data)[0] else: raise ValueError(f'invalid integer length {len(data)}') @staticmethod def signed_integer_from_bytes(data): if len(data) == 1: return struct.unpack('b', data)[0] elif len(data) == 2: return struct.unpack('>h', data)[0] elif len(data) == 4: return struct.unpack('>i', data)[0] elif len(data) == 8: return struct.unpack('>q', data)[0] else: raise ValueError(f'invalid integer length {len(data)}') @staticmethod def list_from_bytes(data): elements = [] while data: element = DataElement.from_bytes(data) elements.append(element) data = data[len(bytes(element)):] return elements @staticmethod def parse_from_bytes(data, offset): element = DataElement.from_bytes(data[offset:]) return offset + len(bytes(element)), element @staticmethod def from_bytes(data): type = data[0] >> 3 size_index = data[0] & 7 value_offset = 0 if size_index == 0: if type == DataElement.NIL: value_size = 0 else: value_size = 1 elif size_index == 1: value_size = 2 elif size_index == 2: value_size = 4 elif size_index == 3: value_size = 8 elif size_index == 4: value_size = 16 elif size_index == 5: value_size = data[1] value_offset = 1 elif size_index == 6: value_size = struct.unpack('>H', data[1:3])[0] value_offset = 2 else: # size_index == 7 value_size = struct.unpack('>I', data[1:5])[0] value_offset = 4 value_data = data[1 + value_offset:1 + value_offset + value_size] constructor = DataElement.type_constructors.get(type) if constructor: if type == DataElement.UNSIGNED_INTEGER or type == DataElement.SIGNED_INTEGER: result = constructor(value_data, value_size) else: result = constructor(value_data) else: result = DataElement(type, value_data) result.bytes = data[:1 + value_offset + value_size] # Keep a copy so we can re-serialize to an exact replica return result def to_bytes(self): return bytes(self) def __bytes__(self): # Return early if we have a cache if self.bytes: return self.bytes if self.type == DataElement.NIL: data = b'' elif self.type == DataElement.UNSIGNED_INTEGER: if self.value < 0: raise ValueError('UNSIGNED_INTEGER cannot be negative') elif self.value_size == 1: data = struct.pack('B', self.value) elif self.value_size == 2: data = struct.pack('>H', self.value) elif self.value_size == 4: data = struct.pack('>I', self.value) elif self.value_size == 8: data = struct.pack('>Q', self.value) else: raise ValueError('invalid value_size') elif self.type == DataElement.SIGNED_INTEGER: if self.value_size == 1: data = struct.pack('b', self.value) elif self.value_size == 2: data = struct.pack('>h', self.value) elif self.value_size == 4: data = struct.pack('>i', self.value) elif self.value_size == 8: data = struct.pack('>q', self.value) else: raise ValueError('invalid value_size') elif self.type == DataElement.UUID: data = bytes(reversed(bytes(self.value))) elif self.type == DataElement.TEXT_STRING or self.type == DataElement.URL: data = self.value.encode('utf8') elif self.type == DataElement.BOOLEAN: data = bytes([1 if self.value else 0]) elif self.type == DataElement.SEQUENCE or self.type == DataElement.ALTERNATIVE: data = b''.join([bytes(element) for element in self.value]) else: data = self.value size = len(data) size_bytes = b'' if self.type == DataElement.NIL: if size != 0: raise ValueError('NIL must be empty') size_index = 0 elif (self.type == DataElement.UNSIGNED_INTEGER or self.type == DataElement.SIGNED_INTEGER or self.type == DataElement.UUID): if size <= 1: size_index = 0 elif size == 2: size_index = 1 elif size == 4: size_index = 2 elif size == 8: size_index = 3 elif size == 16: size_index = 4 else: raise ValueError('invalid data size') elif (self.type == DataElement.TEXT_STRING or self.type == DataElement.SEQUENCE or self.type == DataElement.ALTERNATIVE or self.type == DataElement.URL): if size <= 0xFF: size_index = 5 size_bytes = bytes([size]) elif size <= 0xFFFF: size_index = 6 size_bytes = struct.pack('>H', size) elif size <= 0xFFFFFFFF: size_index = 7 size_bytes = struct.pack('>I', size) else: raise ValueError('invalid data size') elif self.type == DataElement.BOOLEAN: if size != 1: raise ValueError('boolean must be 1 byte') size_index = 0 self.bytes = bytes([self.type << 3 | size_index]) + size_bytes + data return self.bytes def to_string(self, pretty=False, indentation=0): prefix = ' ' * indentation type_name = name_or_number(self.TYPE_NAMES, self.type) if self.type == DataElement.NIL: value_string = '' elif self.type == DataElement.SEQUENCE or self.type == DataElement.ALTERNATIVE: container_separator = '\n' if pretty else '' element_separator = '\n' if pretty else ',' value_string = f'[{container_separator}{element_separator.join([element.to_string(pretty, indentation + 1 if pretty else 0) for element in self.value])}{container_separator}{prefix}]' elif self.type == DataElement.UNSIGNED_INTEGER or self.type == DataElement.SIGNED_INTEGER: value_string = f'{self.value}#{self.value_size}' elif isinstance(self.value, DataElement): value_string = self.value.to_string(pretty, indentation) else: value_string = str(self.value) return f'{prefix}{type_name}({value_string})' def __str__(self): return self.to_string() # ----------------------------------------------------------------------------- class ServiceAttribute: def __init__(self, id, value): self.id = id self.value = value @staticmethod def list_from_data_elements(elements): attribute_list = [] for i in range(0, len(elements) // 2): attribute_id, attribute_value = elements[2 * i:2 * (i + 1)] if attribute_id.type != DataElement.UNSIGNED_INTEGER: logger.warn('attribute ID element is not an integer') continue attribute_list.append(ServiceAttribute(attribute_id.value, attribute_value)) return attribute_list @staticmethod def find_attribute_in_list(attribute_list, attribute_id): return next((attribute.value for attribute in attribute_list if attribute.id == attribute_id), None) @staticmethod def id_name(id): return name_or_number(SDP_ATTRIBUTE_ID_NAMES, id) @staticmethod def is_uuid_in_value(uuid, value): # Find if a uuid matches a value, either directly or recursing into sequences if value.type == DataElement.UUID: return value.value == uuid elif value.type == DataElement.SEQUENCE: for element in value.value: if ServiceAttribute.is_uuid_in_value(uuid, element): return True return False else: return False def to_string(self, color=False): if color: return f'Attribute(id={colors.color(self.id_name(self.id),"magenta")},value={self.value})' else: return f'Attribute(id={self.id_name(self.id)},value={self.value})' def __str__(self): return self.to_string() # ----------------------------------------------------------------------------- class SDP_PDU: ''' See Bluetooth spec @ Vol 3, Part B - 4.2 PROTOCOL DATA UNIT FORMAT ''' sdp_pdu_classes = {} @staticmethod def from_bytes(pdu): pdu_id, transaction_id, parameters_length = struct.unpack_from('>BHH', pdu, 0) cls = SDP_PDU.sdp_pdu_classes.get(pdu_id) if cls is None: instance = SDP_PDU(pdu) instance.name = SDP_PDU.pdu_name(pdu_id) instance.pdu_id = pdu_id instance.transaction_id = transaction_id return instance self = cls.__new__(cls) SDP_PDU.__init__(self, pdu, transaction_id) if hasattr(self, 'fields'): self.init_from_bytes(pdu, 5) return self @staticmethod def parse_service_record_handle_list_preceded_by_count(data, offset): count = struct.unpack_from('>H', data, offset - 2)[0] handle_list = [struct.unpack_from('>I', data, offset + x * 4)[0] for x in range(count)] return offset + count * 4, handle_list @staticmethod def parse_bytes_preceded_by_length(data, offset): length = struct.unpack_from('>H', data, offset - 2)[0] return offset + length, data[offset:offset + length] @staticmethod def error_name(error_code): return name_or_number(SDP_ERROR_NAMES, error_code) @staticmethod def pdu_name(code): return name_or_number(SDP_PDU_NAMES, code) @staticmethod def subclass(fields): def inner(cls): name = cls.__name__ # add a _ character before every uppercase letter, except the SDP_ prefix location = len(name) - 1 while location > 4: if not name[location].isupper(): location -= 1 continue name = name[:location] + '_' + name[location:] location -= 1 cls.name = name.upper() cls.pdu_id = key_with_value(SDP_PDU_NAMES, cls.name) if cls.pdu_id is None: raise KeyError(f'PDU name {cls.name} not found in SDP_PDU_NAMES') cls.fields = fields # Register a factory for this class SDP_PDU.sdp_pdu_classes[cls.pdu_id] = cls return cls return inner def __init__(self, pdu=None, transaction_id=0, **kwargs): if hasattr(self, 'fields') and kwargs: HCI_Object.init_from_fields(self, self.fields, kwargs) if pdu is None: parameters = HCI_Object.dict_to_bytes(kwargs, self.fields) pdu = struct.pack('>BHH', self.pdu_id, transaction_id, len(parameters)) + parameters self.pdu = pdu self.transaction_id = transaction_id def init_from_bytes(self, pdu, offset): return HCI_Object.init_from_bytes(self, pdu, offset, self.fields) def to_bytes(self): return self.pdu def __bytes__(self): return self.to_bytes() def __str__(self): result = f'{color(self.name, "blue")} [TID={self.transaction_id}]' if fields := getattr(self, 'fields', None): result += ':\n' + HCI_Object.format_fields(self.__dict__, fields, ' ') elif len(self.pdu) > 1: result += f': {self.pdu.hex()}' return result # ----------------------------------------------------------------------------- @SDP_PDU.subclass([ ('error_code', {'size': 2, 'mapper': SDP_PDU.error_name}) ]) class SDP_ErrorResponse(SDP_PDU): ''' See Bluetooth spec @ Vol 3, Part B - 4.4.1 SDP_ErrorResponse PDU ''' # ----------------------------------------------------------------------------- @SDP_PDU.subclass([ ('service_search_pattern', DataElement.parse_from_bytes), ('maximum_service_record_count', '>2'), ('continuation_state', '*') ]) class SDP_ServiceSearchRequest(SDP_PDU): ''' See Bluetooth spec @ Vol 3, Part B - 4.5.1 SDP_ServiceSearchRequest PDU ''' # ----------------------------------------------------------------------------- @SDP_PDU.subclass([ ('total_service_record_count', '>2'), ('current_service_record_count', '>2'), ('service_record_handle_list', SDP_PDU.parse_service_record_handle_list_preceded_by_count), ('continuation_state', '*') ]) class SDP_ServiceSearchResponse(SDP_PDU): ''' See Bluetooth spec @ Vol 3, Part B - 4.5.2 SDP_ServiceSearchResponse PDU ''' # ----------------------------------------------------------------------------- @SDP_PDU.subclass([ ('service_record_handle', '>4'), ('maximum_attribute_byte_count', '>2'), ('attribute_id_list', DataElement.parse_from_bytes), ('continuation_state', '*') ]) class SDP_ServiceAttributeRequest(SDP_PDU): ''' See Bluetooth spec @ Vol 3, Part B - 4.6.1 SDP_ServiceAttributeRequest PDU ''' # ----------------------------------------------------------------------------- @SDP_PDU.subclass([ ('attribute_list_byte_count', '>2'), ('attribute_list', SDP_PDU.parse_bytes_preceded_by_length), ('continuation_state', '*') ]) class SDP_ServiceAttributeResponse(SDP_PDU): ''' See Bluetooth spec @ Vol 3, Part B - 4.6.2 SDP_ServiceAttributeResponse PDU ''' # ----------------------------------------------------------------------------- @SDP_PDU.subclass([ ('service_search_pattern', DataElement.parse_from_bytes), ('maximum_attribute_byte_count', '>2'), ('attribute_id_list', DataElement.parse_from_bytes), ('continuation_state', '*') ]) class SDP_ServiceSearchAttributeRequest(SDP_PDU): ''' See Bluetooth spec @ Vol 3, Part B - 4.7.1 SDP_ServiceSearchAttributeRequest PDU ''' # ----------------------------------------------------------------------------- @SDP_PDU.subclass([ ('attribute_lists_byte_count', '>2'), ('attribute_lists', SDP_PDU.parse_bytes_preceded_by_length), ('continuation_state', '*') ]) class SDP_ServiceSearchAttributeResponse(SDP_PDU): ''' See Bluetooth spec @ Vol 3, Part B - 4.7.2 SDP_ServiceSearchAttributeResponse PDU ''' # ----------------------------------------------------------------------------- class Client: def __init__(self, device): self.device = device self.pending_request = None self.channel = None async def connect(self, connection): result = await self.device.l2cap_channel_manager.connect(connection, SDP_PSM) self.channel = result async def disconnect(self): if self.channel: await self.channel.disconnect() self.channel = None async def search_services(self, uuids): if self.pending_request is not None: raise InvalidStateError('request already pending') service_search_pattern = DataElement.sequence([DataElement.uuid(uuid) for uuid in uuids]) # Request and accumulate until there's no more continuation service_record_handle_list = [] continuation_state = bytes([0]) watchdog = SDP_CONTINUATION_WATCHDOG while watchdog > 0: response_pdu = await self.channel.send_request( SDP_ServiceSearchRequest( transaction_id = 0, # Transaction ID TODO: pick a real value service_search_pattern = service_search_pattern, maximum_service_record_count = 0xFFFF, continuation_state = continuation_state ) ) response = SDP_PDU.from_bytes(response_pdu) logger.debug(f'<<< Response: {response}') service_record_handle_list += response.service_record_handle_list continuation_state = response.continuation_state if len(continuation_state) == 1 and continuation_state[0] == 0: break logger.debug(f'continuation: {continuation_state.hex()}') watchdog -= 1 return service_record_handle_list async def search_attributes(self, uuids, attribute_ids): if self.pending_request is not None: raise InvalidStateError('request already pending') service_search_pattern = DataElement.sequence([DataElement.uuid(uuid) for uuid in uuids]) attribute_id_list = DataElement.sequence( [ DataElement.unsigned_integer(attribute_id[0], value_size=attribute_id[1]) if type(attribute_id) is tuple else DataElement.unsigned_integer_16(attribute_id) for attribute_id in attribute_ids ] ) # Request and accumulate until there's no more continuation accumulator = b'' continuation_state = bytes([0]) watchdog = SDP_CONTINUATION_WATCHDOG while watchdog > 0: response_pdu = await self.channel.send_request( SDP_ServiceSearchAttributeRequest( transaction_id = 0, # Transaction ID TODO: pick a real value service_search_pattern = service_search_pattern, maximum_attribute_byte_count = 0xFFFF, attribute_id_list = attribute_id_list, continuation_state = continuation_state ) ) response = SDP_PDU.from_bytes(response_pdu) logger.debug(f'<<< Response: {response}') accumulator += response.attribute_lists continuation_state = response.continuation_state if len(continuation_state) == 1 and continuation_state[0] == 0: break logger.debug(f'continuation: {continuation_state.hex()}') watchdog -= 1 # Parse the result into attribute lists attribute_lists_sequences = DataElement.from_bytes(accumulator) if attribute_lists_sequences.type != DataElement.SEQUENCE: logger.warn('unexpected data type') return [] return [ ServiceAttribute.list_from_data_elements(sequence.value) for sequence in attribute_lists_sequences.value if sequence.type == DataElement.SEQUENCE ] async def get_attributes(self, service_record_handle, attribute_ids): if self.pending_request is not None: raise InvalidStateError('request already pending') attribute_id_list = DataElement.sequence( [ DataElement.unsigned_integer(attribute_id[0], value_size=attribute_id[1]) if type(attribute_id) is tuple else DataElement.unsigned_integer_16(attribute_id) for attribute_id in attribute_ids ] ) # Request and accumulate until there's no more continuation accumulator = b'' continuation_state = bytes([0]) watchdog = SDP_CONTINUATION_WATCHDOG while watchdog > 0: response_pdu = await self.channel.send_request( SDP_ServiceAttributeRequest( transaction_id = 0, # Transaction ID TODO: pick a real value service_record_handle = service_record_handle, maximum_attribute_byte_count = 0xFFFF, attribute_id_list = attribute_id_list, continuation_state = continuation_state ) ) response = SDP_PDU.from_bytes(response_pdu) logger.debug(f'<<< Response: {response}') accumulator += response.attribute_list continuation_state = response.continuation_state if len(continuation_state) == 1 and continuation_state[0] == 0: break logger.debug(f'continuation: {continuation_state.hex()}') watchdog -= 1 # Parse the result into a list of attributes attribute_list_sequence = DataElement.from_bytes(accumulator) if attribute_list_sequence.type != DataElement.SEQUENCE: logger.warn('unexpected data type') return [] return ServiceAttribute.list_from_data_elements(attribute_list_sequence.value) # ----------------------------------------------------------------------------- class Server: CONTINUATION_STATE = bytes([0x01, 0x43]) def __init__(self, device): self.device = device self.service_records = {} # Service records maps, by record handle self.current_response = None def register(self, l2cap_channel_manager): l2cap_channel_manager.register_server(SDP_PSM, self.on_connection) def send_response(self, response): logger.debug(f'{color(">>> Sending SDP Response", "blue")}: {response}') self.channel.send_pdu(response) def match_services(self, search_pattern): # Find the services for which the attributes in the pattern is a subset of the # service's attribute values (NOTE: the value search recurses into sequences) matching_services = {} for handle, service in self.service_records.items(): for uuid in search_pattern.value: found = False for attribute in service: if ServiceAttribute.is_uuid_in_value(uuid.value, attribute.value): found = True break if found: matching_services[handle] = service break return matching_services def on_connection(self, channel): self.channel = channel self.channel.sink = self.on_pdu def on_pdu(self, pdu): try: sdp_pdu = SDP_PDU.from_bytes(pdu) except Exception as error: logger.warn(color(f'failed to parse SDP Request PDU: {error}', 'red')) self.send_response( SDP_ErrorResponse( transaction_id = 0, error_code = SDP_INVALID_REQUEST_SYNTAX_ERROR ) ) logger.debug(f'{color("<<< Received SDP Request", "green")}: {sdp_pdu}') # Find the handler method handler_name = f'on_{sdp_pdu.name.lower()}' handler = getattr(self, handler_name, None) if handler: try: handler(sdp_pdu) except Exception as error: logger.warning(f'{color("!!! Exception in handler:", "red")} {error}') self.send_response( SDP_ErrorResponse( transaction_id = sdp_pdu.transaction_id, error_code = SDP_INSUFFICIENT_RESOURCES_TO_SATISFY_REQUEST_ERROR ) ) else: logger.error(color('SDP Request not handled???', 'red')) self.send_response( SDP_ErrorResponse( transaction_id = sdp_pdu.transaction_id, error_code = SDP_INVALID_REQUEST_SYNTAX_ERROR ) ) def get_next_response_payload(self, maximum_size): if len(self.current_response) > maximum_size: payload = self.current_response[:maximum_size] continuation_state = Server.CONTINUATION_STATE self.current_response = self.current_response[maximum_size:] else: payload = self.current_response continuation_state = bytes([0]) self.current_response = None return (payload, continuation_state) @staticmethod def get_service_attributes(service, attribute_ids): attributes = [] for attribute_id in attribute_ids: if attribute_id.value_size == 4: # Attribute ID range id_range_start = attribute_id.value >> 16 id_range_end = attribute_id.value & 0xFFFF else: id_range_start = attribute_id.value id_range_end = attribute_id.value attributes += [ attribute for attribute in service if attribute.id >= id_range_start and attribute.id <= id_range_end ] # Return the maching attributes, sorted by attribute id attributes.sort(key = lambda x: x.id) attribute_list = DataElement.sequence([]) for attribute in attributes: attribute_list.value.append(DataElement.unsigned_integer_16(attribute.id)) attribute_list.value.append(attribute.value) return attribute_list def on_sdp_service_search_request(self, request): # Check if this is a continuation if len(request.continuation_state) > 1: if not self.current_response: self.send_response( SDP_ErrorResponse( transaction_id = request.transaction_id, error_code = SDP_INVALID_CONTINUATION_STATE_ERROR ) ) return else: # Cleanup any partial response leftover self.current_response = None # Find the matching services matching_services = self.match_services(request.service_search_pattern) service_record_handles = list(matching_services.keys()) # Only return up to the maximum requested service_record_handles_subset = service_record_handles[:request.maximum_service_record_count] # Serialize to a byte array, and remember the total count logger.debug(f'Service Record Handles: {service_record_handles}') self.current_response = ( len(service_record_handles), service_record_handles_subset ) # Respond, keeping any unsent handles for later service_record_handles = self.current_response[1][:request.maximum_service_record_count] self.current_response = ( self.current_response[0], self.current_response[1][request.maximum_service_record_count:] ) continuation_state = Server.CONTINUATION_STATE if self.current_response[1] else bytes([0]) service_record_handle_list = b''.join([struct.pack('>I', handle) for handle in service_record_handles]) self.send_response( SDP_ServiceSearchResponse( transaction_id = request.transaction_id, total_service_record_count = self.current_response[0], current_service_record_count = len(service_record_handles), service_record_handle_list = service_record_handle_list, continuation_state = continuation_state ) ) def on_sdp_service_attribute_request(self, request): # Check if this is a continuation if len(request.continuation_state) > 1: if not self.current_response: self.send_response( SDP_ErrorResponse( transaction_id = request.transaction_id, error_code = SDP_INVALID_CONTINUATION_STATE_ERROR ) ) return else: # Cleanup any partial response leftover self.current_response = None # Check that the service exists service = self.service_records.get(request.service_record_handle) if service is None: self.send_response( SDP_ErrorResponse( transaction_id = request.transaction_id, error_code = SDP_INVALID_SERVICE_RECORD_HANDLE_ERROR ) ) return # Get the attributes for the service attribute_list = Server.get_service_attributes(service, request.attribute_id_list.value) # Serialize to a byte array logger.debug(f'Attributes: {attribute_list}') self.current_response = bytes(attribute_list) # Respond, keeping any pending chunks for later attribute_list, continuation_state = self.get_next_response_payload(request.maximum_attribute_byte_count) self.send_response( SDP_ServiceAttributeResponse( transaction_id = request.transaction_id, attribute_list_byte_count = len(attribute_list), attribute_list = attribute_list, continuation_state = continuation_state ) ) def on_sdp_service_search_attribute_request(self, request): # Check if this is a continuation if len(request.continuation_state) > 1: if not self.current_response: self.send_response( SDP_ErrorResponse( transaction_id = request.transaction_id, error_code = SDP_INVALID_CONTINUATION_STATE_ERROR ) ) else: # Cleanup any partial response leftover self.current_response = None # Find the matching services matching_services = self.match_services(request.service_search_pattern).values() # Filter the required attributes attribute_lists = DataElement.sequence([]) for service in matching_services: attribute_list = Server.get_service_attributes(service, request.attribute_id_list.value) if attribute_list.value: attribute_lists.value.append(attribute_list) # Serialize to a byte array logger.debug(f'Search response: {attribute_lists}') self.current_response = bytes(attribute_lists) # Respond, keeping any pending chunks for later attribute_lists, continuation_state = self.get_next_response_payload(request.maximum_attribute_byte_count) self.send_response( SDP_ServiceSearchAttributeResponse( transaction_id = request.transaction_id, attribute_lists_byte_count = len(attribute_lists), attribute_lists = attribute_lists, continuation_state = continuation_state ) )