# 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 asyncio import logging from pyee import EventEmitter from colors import color from .hci import * from .l2cap import * from .att import * from .gatt import * from .smp import * from .core import ConnectionParameters # ----------------------------------------------------------------------------- # Logging # ----------------------------------------------------------------------------- logger = logging.getLogger(__name__) # ----------------------------------------------------------------------------- # Constants # ----------------------------------------------------------------------------- HOST_DEFAULT_HC_LE_ACL_DATA_PACKET_LENGTH = 27 HOST_HC_TOTAL_NUM_LE_ACL_DATA_PACKETS = 1 HOST_DEFAULT_HC_ACL_DATA_PACKET_LENGTH = 27 HOST_HC_TOTAL_NUM_ACL_DATA_PACKETS = 1 # ----------------------------------------------------------------------------- class Connection: def __init__(self, host, handle, role, peer_address): self.host = host self.handle = handle self.role = role self.peer_address = peer_address self.assembler = HCI_AclDataPacketAssembler(self.on_acl_pdu) def on_hci_acl_data_packet(self, packet): self.assembler.feed_packet(packet) def on_acl_pdu(self, pdu): l2cap_pdu = L2CAP_PDU.from_bytes(pdu) if l2cap_pdu.cid == ATT_CID: self.host.on_gatt_pdu(self, l2cap_pdu.payload) elif l2cap_pdu.cid == SMP_CID: self.host.on_smp_pdu(self, l2cap_pdu.payload) else: self.host.on_l2cap_pdu(self, l2cap_pdu.cid, l2cap_pdu.payload) # ----------------------------------------------------------------------------- class Host(EventEmitter): def __init__(self, controller_source = None, controller_sink = None): super().__init__() self.hci_sink = None self.ready = False # True when we can accept incoming packets self.connections = {} # Connections, by connection handle self.pending_command = None self.pending_response = None self.hc_le_acl_data_packet_length = HOST_DEFAULT_HC_LE_ACL_DATA_PACKET_LENGTH self.hc_total_num_le_acl_data_packets = HOST_HC_TOTAL_NUM_LE_ACL_DATA_PACKETS self.hc_acl_data_packet_length = HOST_DEFAULT_HC_ACL_DATA_PACKET_LENGTH self.hc_total_num_acl_data_packets = HOST_HC_TOTAL_NUM_ACL_DATA_PACKETS self.acl_packet_queue = collections.deque() self.acl_packets_in_flight = 0 self.local_supported_commands = bytes(64) self.command_semaphore = asyncio.Semaphore(1) self.long_term_key_provider = None self.link_key_provider = None # Connect to the source and sink if specified if controller_source: controller_source.set_packet_sink(self) if controller_sink: self.set_packet_sink(controller_sink) async def reset(self): await self.send_command(HCI_Reset_Command()) self.ready = True response = await self.send_command(HCI_Read_Local_Supported_Commands_Command()) if response.return_parameters.status != HCI_SUCCESS: raise ProtocolError(response.return_parameters.status, 'hci') self.local_supported_commands = response.return_parameters.supported_commands await self.send_command(HCI_Set_Event_Mask_Command(event_mask = bytes.fromhex('FFFFFFFFFFFFFFFF'))) await self.send_command(HCI_LE_Set_Event_Mask_Command(le_event_mask = bytes.fromhex('FFFFF00000000000'))) await self.send_command(HCI_Read_Local_Version_Information_Command()) await self.send_command(HCI_Write_LE_Host_Support_Command(le_supported_host = 1, simultaneous_le_host = 0)) response = await self.send_command(HCI_LE_Read_Buffer_Size_Command()) if response.return_parameters.status == HCI_SUCCESS: self.hc_le_acl_data_packet_length = response.return_parameters.hc_le_acl_data_packet_length self.hc_total_num_le_acl_data_packets = response.return_parameters.hc_total_num_le_acl_data_packets logger.debug(f'HCI LE ACL flow control: hc_le_acl_data_packet_length={response.return_parameters.hc_le_acl_data_packet_length}, hc_total_num_le_acl_data_packets={response.return_parameters.hc_total_num_le_acl_data_packets}') else: logger.warn(f'HCI_LE_Read_Buffer_Size_Command failed: {response.return_parameters.status}') if response.return_parameters.hc_le_acl_data_packet_length == 0 or response.return_parameters.hc_total_num_le_acl_data_packets == 0: # Read the non-LE-specific values response = await self.send_command(HCI_Read_Buffer_Size_Command()) if response.return_parameters.status == HCI_SUCCESS: self.hc_acl_data_packet_length = response.return_parameters.hc_le_acl_data_packet_length self.hc_le_acl_data_packet_length = self.hc_le_acl_data_packet_length or self.hc_acl_data_packet_length self.hc_total_num_acl_data_packets = response.return_parameters.hc_total_num_le_acl_data_packets self.hc_total_num_le_acl_data_packets = self.hc_total_num_le_acl_data_packets or self.hc_total_num_acl_data_packets logger.debug(f'HCI LE ACL flow control: hc_le_acl_data_packet_length={self.hc_le_acl_data_packet_length}, hc_total_num_le_acl_data_packets={self.hc_total_num_le_acl_data_packets}') else: logger.warn(f'HCI_Read_Buffer_Size_Command failed: {response.return_parameters.status}') self.reset_done = True @property def controller(self): return self.hci_sink @controller.setter def controller(self, controller): self.set_packet_sink(controller) if controller: controller.set_packet_sink(self) def set_packet_sink(self, sink): self.hci_sink = sink def send_hci_packet(self, packet): self.hci_sink.on_packet(packet.to_bytes()) async def send_command(self, command): logger.debug(f'{color("### HOST -> CONTROLLER", "blue")}: {command}') # Wait until we can send (only one pending command at a time) async with self.command_semaphore: assert(self.pending_command is None) assert(self.pending_response is None) # Create a future value to hold the eventual response self.pending_response = asyncio.get_running_loop().create_future() self.pending_command = command try: self.send_hci_packet(command) response = await self.pending_response # TODO: check error values return response except Exception as error: logger.warning(f'{color("!!! Exception while sending HCI packet:", "red")} {error}') # raise error finally: self.pending_command = None self.pending_response = None # Use this method to send a command from a task def send_command_sync(self, command): async def send_command(command): await self.send_command(command) asyncio.create_task(send_command(command)) def send_l2cap_pdu(self, connection_handle, cid, pdu): l2cap_pdu = L2CAP_PDU(cid, pdu).to_bytes() # Send the data to the controller via ACL packets bytes_remaining = len(l2cap_pdu) offset = 0 pb_flag = 0 while bytes_remaining: data_total_length = min(bytes_remaining, self.hc_le_acl_data_packet_length) acl_packet = HCI_AclDataPacket( connection_handle = connection_handle, pb_flag = pb_flag, bc_flag = 0, data_total_length = data_total_length, data = l2cap_pdu[offset:offset + data_total_length] ) logger.debug(f'{color("### HOST -> CONTROLLER", "blue")}: (CID={cid}) {acl_packet}') self.queue_acl_packet(acl_packet) pb_flag = 1 offset += data_total_length bytes_remaining -= data_total_length def queue_acl_packet(self, acl_packet): self.acl_packet_queue.appendleft(acl_packet) self.check_acl_packet_queue() if len(self.acl_packet_queue): logger.debug(f'{self.acl_packets_in_flight} ACL packets in flight, {len(self.acl_packet_queue)} in queue') def check_acl_packet_queue(self): # Send all we can while len(self.acl_packet_queue) > 0 and self.acl_packets_in_flight < self.hc_total_num_le_acl_data_packets: packet = self.acl_packet_queue.pop() self.send_hci_packet(packet) self.acl_packets_in_flight += 1 # Packet Sink protocol (packets coming from the controller via HCI) def on_packet(self, packet): hci_packet = HCI_Packet.from_bytes(packet) if self.ready or ( hci_packet.hci_packet_type == HCI_EVENT_PACKET and hci_packet.event_code == HCI_COMMAND_COMPLETE_EVENT and hci_packet.command_opcode == HCI_RESET_COMMAND ): self.on_hci_packet(hci_packet) else: logger.debug('reset not done, ignoring packet from controller') def on_hci_packet(self, packet): logger.debug(f'{color("### CONTROLLER -> HOST", "green")}: {packet}') # If the packet is a command, invoke the handler for this packet if packet.hci_packet_type == HCI_COMMAND_PACKET: self.on_hci_command_packet(packet) elif packet.hci_packet_type == HCI_EVENT_PACKET: self.on_hci_event_packet(packet) elif packet.hci_packet_type == HCI_ACL_DATA_PACKET: self.on_hci_acl_data_packet(packet) else: logger.warning(f'!!! unknown packet type {packet.hci_packet_type}') def on_hci_command_packet(self, command): logger.warning(f'!!! unexpected command packet: {command}') def on_hci_event_packet(self, event): handler_name = f'on_{event.name.lower()}' handler = getattr(self, handler_name, self.on_hci_event) handler(event) def on_hci_acl_data_packet(self, packet): # Look for the connection to which this data belongs if connection := self.connections.get(packet.connection_handle): connection.on_hci_acl_data_packet(packet) def on_gatt_pdu(self, connection, pdu): self.emit('gatt_pdu', connection.handle, pdu) def on_smp_pdu(self, connection, pdu): self.emit('smp_pdu', connection.handle, pdu) def on_l2cap_pdu(self, connection, cid, pdu): self.emit('l2cap_pdu', connection.handle, cid, pdu) def on_command_processed(self, event): if self.pending_response: # Check that it is what we were expecting if self.pending_command.op_code != event.command_opcode: logger.warning(f'!!! command result mismatch, expected 0x{self.pending_command.op_code:X} but got 0x{event.command_opcode:X}') self.pending_response.set_result(event) else: logger.warning('!!! no pending response future to set') ############################################################ # HCI handlers ############################################################ def on_hci_event(self, event): logger.warning(f'{color(f"--- Ignoring event {event}", "red")}') def on_hci_command_complete_event(self, event): if event.command_opcode == 0: # This is used just for the Num_HCI_Command_Packets field, not related to an actual command logger.debug('no-command event') else: return self.on_command_processed(event) def on_hci_command_status_event(self, event): return self.on_command_processed(event) def on_hci_number_of_completed_packets_event(self, event): total_packets = sum(event.num_completed_packets) if total_packets <= self.acl_packets_in_flight: self.acl_packets_in_flight -= total_packets self.check_acl_packet_queue() else: logger.warning(color(f'!!! {total_packets} completed but only {self.acl_packets_in_flight} in flight')) self.acl_packets_in_flight = 0 # Classic only def on_hci_connection_request_event(self, event): # For now, just accept everything # TODO: delegate the decision self.send_command_sync( HCI_Accept_Connection_Request_Command( bd_addr = event.bd_addr, role = 0x01 # Remain the peripheral ) ) def on_hci_le_connection_complete_event(self, event): # Check if this is a cancellation if event.status == HCI_SUCCESS: # Create/update the connection logger.debug(f'### CONNECTION: [0x{event.connection_handle:04X}] {event.peer_address} as {HCI_Constant.role_name(event.role)}') connection = self.connections.get(event.connection_handle) if connection is None: connection = Connection(self, event.connection_handle, event.role, event.peer_address) self.connections[event.connection_handle] = connection # Notify the client connection_parameters = ConnectionParameters( event.conn_interval, event.conn_latency, event.supervision_timeout ) self.emit( 'connection', event.connection_handle, BT_LE_TRANSPORT, event.peer_address, None, event.role, connection_parameters ) else: logger.debug(f'### CONNECTION FAILED: {event.status}') # Notify the listeners self.emit('connection_failure', event.status) def on_hci_le_enhanced_connection_complete_event(self, event): # Just use the same implementation as for the non-enhanced event for now self.on_hci_le_connection_complete_event(event) def on_hci_connection_complete_event(self, event): if event.status == HCI_SUCCESS: # Create/update the connection logger.debug(f'### BR/EDR CONNECTION: [0x{event.connection_handle:04X}] {event.bd_addr}') connection = self.connections.get(event.connection_handle) if connection is None: connection = Connection(self, event.connection_handle, BT_CENTRAL_ROLE, event.bd_addr) self.connections[event.connection_handle] = connection # Notify the client self.emit( 'connection', event.connection_handle, BT_BR_EDR_TRANSPORT, event.bd_addr, None, BT_CENTRAL_ROLE, None ) else: logger.debug(f'### BR/EDR CONNECTION FAILED: {event.status}') # Notify the client self.emit('connection_failure', event.status) def on_hci_disconnection_complete_event(self, event): # Find the connection if (connection := self.connections.get(event.connection_handle)) is None: logger.warning('!!! DISCONNECTION COMPLETE: unknown handle') return if event.status == HCI_SUCCESS: logger.debug(f'### DISCONNECTION: [0x{event.connection_handle:04X}] {connection.peer_address} as {HCI_Constant.role_name(connection.role)}, reason={event.reason}') del self.connections[event.connection_handle] # Notify the listeners self.emit('disconnection', event.connection_handle, event.reason) else: logger.debug(f'### DISCONNECTION FAILED: {event.status}') # Notify the listeners self.emit('disconnection_failure', event.status) def on_hci_le_connection_update_complete_event(self, event): if (connection := self.connections.get(event.connection_handle)) is None: logger.warning('!!! CONNECTION PARAMETERS UPDATE COMPLETE: unknown handle') return # Notify the client if event.status == HCI_SUCCESS: connection_parameters = ConnectionParameters( event.conn_interval, event.conn_latency, event.supervision_timeout ) self.emit('connection_parameters_update', connection.handle, connection_parameters) else: self.emit('connection_parameters_update_failure', connection.handle, event.status) def on_hci_le_phy_update_complete_event(self, event): if (connection := self.connections.get(event.connection_handle)) is None: logger.warning('!!! CONNECTION PHY UPDATE COMPLETE: unknown handle') return # Notify the client if event.status == HCI_SUCCESS: connection_phy = ConnectionPHY(event.tx_phy, event.rx_phy) self.emit('connection_phy_update', connection.handle, connection_phy) else: self.emit('connection_phy_update_failure', connection.handle, event.status) def on_hci_le_advertising_report_event(self, event): for report in event.reports: self.emit( 'advertising_report', report.address, report.data, report.rssi, report.event_type ) def on_hci_le_remote_connection_parameter_request_event(self, event): if event.connection_handle not in self.connections: logger.warning('!!! REMOTE CONNECTION PARAMETER REQUEST: unknown handle') return # For now, just accept everything # TODO: delegate the decision self.send_command_sync( HCI_LE_Remote_Connection_Parameter_Request_Reply_Command( connection_handle = event.connection_handle, interval_min = event.interval_min, interval_max = event.interval_max, latency = event.latency, timeout = event.timeout, minimum_ce_length = 0, maximum_ce_length = 0 ) ) def on_hci_le_long_term_key_request_event(self, event): if (connection := self.connections.get(event.connection_handle)) is None: logger.warning('!!! LE LONG TERM KEY REQUEST: unknown handle') return async def send_long_term_key(): if self.long_term_key_provider is None: logger.debug('no long term key provider') long_term_key = None else: long_term_key = await self.long_term_key_provider( connection.handle, event.random_number, event.encryption_diversifier ) if long_term_key: response = HCI_LE_Long_Term_Key_Request_Reply_Command( connection_handle = event.connection_handle, long_term_key = long_term_key ) else: response = HCI_LE_Long_Term_Key_Request_Negative_Reply_Command( connection_handle = event.connection_handle ) await self.send_command(response) asyncio.create_task(send_long_term_key()) def on_hci_synchronous_connection_complete_event(self, event): pass def on_hci_synchronous_connection_changed_event(self, event): pass def on_hci_role_change_event(self, event): if event.status == HCI_SUCCESS: logger.debug(f'role change for {event.bd_addr}: {HCI_Constant.role_name(event.new_role)}') # TODO: lookup the connection and update the role else: logger.debug(f'role change for {event.bd_addr} failed: {HCI_Constant.error_name(event.status)}') def on_hci_le_data_length_change_event(self, event): self.emit( 'connection_data_length_change', event.connection_handle, event.max_tx_octets, event.max_tx_time, event.max_rx_octets, event.max_rx_time ) def on_hci_authentication_complete_event(self, event): # Notify the client if event.status == HCI_SUCCESS: self.emit('connection_authentication_complete', event.connection_handle) else: self.emit('connection_authentication_failure', event.connection_handle, event.status) def on_hci_encryption_change_event(self, event): # Notify the client if event.status == HCI_SUCCESS: self.emit('connection_encryption_change', event.connection_handle, event.encryption_enabled) else: self.emit('connection_encryption_failure', event.connection_handle, event.status) def on_hci_encryption_key_refresh_complete_event(self, event): # Notify the client if event.status == HCI_SUCCESS: self.emit('connection_encryption_key_refresh', event.connection_handle) else: self.emit('connection_encryption_key_refresh_failure', event.connection_handle, event.status) def on_hci_link_supervision_timeout_changed_event(self, event): pass def on_hci_max_slots_change_event(self, event): pass def on_hci_page_scan_repetition_mode_change_event(self, event): pass def on_hci_link_key_notification_event(self, event): logger.debug(f'link key for {event.bd_addr}: {event.link_key.hex()}, type={HCI_Constant.link_key_type_name(event.key_type)}') self.emit('link_key', event.bd_addr, event.link_key, event.key_type) def on_hci_simple_pairing_complete_event(self, event): logger.debug(f'simple pairing complete for {event.bd_addr}: status={HCI_Constant.status_name(event.status)}') def on_hci_pin_code_request_event(self, event): # For now, just refuse all requests # TODO: delegate the decision self.send_command_sync( HCI_PIN_Code_Request_Negative_Reply_Command( bd_addr = event.bd_addr ) ) def on_hci_link_key_request_event(self, event): async def send_link_key(): if self.link_key_provider is None: logger.debug('no link key provider') link_key = None else: link_key = await self.link_key_provider(event.bd_addr) if link_key: response = HCI_Link_Key_Request_Reply_Command( bd_addr = event.bd_addr, link_key = link_key ) else: response = HCI_Link_Key_Request_Negative_Reply_Command( bd_addr = event.bd_addr ) await self.send_command(response) asyncio.create_task(send_link_key()) def on_hci_io_capability_request_event(self, event): # For now, just return NoInputNoOutput and no MITM # TODO: delegate the decision self.send_command_sync( HCI_IO_Capability_Request_Reply_Command( bd_addr = event.bd_addr, io_capability = HCI_NO_INPUT_NO_OUTPUT_IO_CAPABILITY, oob_data_present = 0x00, authentication_requirements = 0x00 # 0x02 # FIXME: testing only ) ) def on_hci_io_capability_response_event(self, event): pass def on_hci_user_confirmation_request_event(self, event): # For now, just confirm everything # TODO: delegate the decision self.send_command_sync( HCI_User_Confirmation_Request_Reply_Command(bd_addr = event.bd_addr) ) def on_hci_inquiry_complete_event(self, event): self.emit('inquiry_complete') def on_hci_inquiry_result_with_rssi_event(self, event): for response in event.responses: self.emit( 'inquiry_result', response.bd_addr, response.class_of_device, b'', response.rssi ) def on_hci_extended_inquiry_result_event(self, event): self.emit( 'inquiry_result', event.bd_addr, event.class_of_device, event.extended_inquiry_response, event.rssi )