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298 lines
12 KiB
Python
298 lines
12 KiB
Python
# Copyright 2021-2022 Google LLC
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# https://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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# -----------------------------------------------------------------------------
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# Imports
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# -----------------------------------------------------------------------------
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from __future__ import annotations
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import datetime
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import logging
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from collections.abc import Callable, MutableMapping
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from typing import Any, cast
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from bumble import avc, avctp, avdtp, avrcp, crypto, rfcomm, sdp
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from bumble.att import ATT_CID, ATT_PDU
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from bumble.colors import color
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from bumble.core import name_or_number
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from bumble.hci import (
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HCI_ACL_DATA_PACKET,
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HCI_DISCONNECTION_COMPLETE_EVENT,
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HCI_EVENT_PACKET,
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Address,
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HCI_AclDataPacket,
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HCI_AclDataPacketAssembler,
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HCI_Disconnection_Complete_Event,
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HCI_Event,
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HCI_Packet,
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)
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from bumble.l2cap import (
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L2CAP_LE_SIGNALING_CID,
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L2CAP_PDU,
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L2CAP_SIGNALING_CID,
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CommandCode,
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L2CAP_Connection_Request,
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L2CAP_Connection_Response,
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L2CAP_Control_Frame,
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)
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from bumble.smp import SMP_CID, SMP_Command
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# -----------------------------------------------------------------------------
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# Logging
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# -----------------------------------------------------------------------------
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logger = logging.getLogger(__name__)
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# -----------------------------------------------------------------------------
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PSM_NAMES = {
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rfcomm.RFCOMM_PSM: 'RFCOMM',
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sdp.SDP_PSM: 'SDP',
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avdtp.AVDTP_PSM: 'AVDTP',
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avctp.AVCTP_PSM: 'AVCTP',
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# TODO: add more PSM values
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}
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AVCTP_PID_NAMES = {avrcp.AVRCP_PID: 'AVRCP'}
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# -----------------------------------------------------------------------------
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class PacketTracer:
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class AclStream:
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psms: MutableMapping[int, int]
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peer: PacketTracer.AclStream | None
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avdtp_assemblers: MutableMapping[int, avdtp.MessageAssembler]
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avctp_assemblers: MutableMapping[int, avctp.MessageAssembler]
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def __init__(self, analyzer: PacketTracer.Analyzer) -> None:
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self.analyzer = analyzer
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self.packet_assembler = HCI_AclDataPacketAssembler(self.on_acl_pdu)
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self.avdtp_assemblers = {} # AVDTP assemblers, by source_cid
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self.avctp_assemblers = {} # AVCTP assemblers, by source_cid
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self.psms = {} # PSM, by source_cid
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self.peer = None
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# pylint: disable=too-many-nested-blocks
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def on_acl_pdu(self, pdu: bytes) -> None:
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l2cap_pdu = L2CAP_PDU.from_bytes(pdu)
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self.analyzer.emit(l2cap_pdu)
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if l2cap_pdu.cid == ATT_CID:
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att_pdu = ATT_PDU.from_bytes(l2cap_pdu.payload)
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self.analyzer.emit(att_pdu)
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elif l2cap_pdu.cid == SMP_CID:
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smp_command = SMP_Command.from_bytes(l2cap_pdu.payload)
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self.analyzer.emit(smp_command)
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elif l2cap_pdu.cid in (L2CAP_SIGNALING_CID, L2CAP_LE_SIGNALING_CID):
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control_frame = L2CAP_Control_Frame.from_bytes(l2cap_pdu.payload)
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self.analyzer.emit(control_frame)
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# Check if this signals a new channel
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if control_frame.code == CommandCode.L2CAP_CONNECTION_REQUEST:
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connection_request = cast(L2CAP_Connection_Request, control_frame)
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self.psms[connection_request.source_cid] = connection_request.psm
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elif control_frame.code == CommandCode.L2CAP_CONNECTION_RESPONSE:
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connection_response = cast(L2CAP_Connection_Response, control_frame)
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if (
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connection_response.result
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== L2CAP_Connection_Response.Result.CONNECTION_SUCCESSFUL
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):
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if self.peer and (
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psm := self.peer.psms.get(connection_response.source_cid)
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):
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# Found a pending connection
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self.psms[connection_response.destination_cid] = psm
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# For AVDTP connections, create a packet assembler for
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# each direction
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if psm == avdtp.AVDTP_PSM:
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self.avdtp_assemblers[
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connection_response.source_cid
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] = avdtp.MessageAssembler(self.on_avdtp_message)
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self.peer.avdtp_assemblers[
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connection_response.destination_cid
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] = avdtp.MessageAssembler(self.peer.on_avdtp_message)
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elif psm == avctp.AVCTP_PSM:
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self.avctp_assemblers[
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connection_response.source_cid
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] = avctp.MessageAssembler(self.on_avctp_message)
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self.peer.avctp_assemblers[
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connection_response.destination_cid
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] = avctp.MessageAssembler(self.peer.on_avctp_message)
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else:
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# Try to find the PSM associated with this PDU
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if self.peer and (psm := self.peer.psms.get(l2cap_pdu.cid)):
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if psm == sdp.SDP_PSM:
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sdp_pdu = sdp.SDP_PDU.from_bytes(l2cap_pdu.payload)
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self.analyzer.emit(sdp_pdu)
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elif psm == rfcomm.RFCOMM_PSM:
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rfcomm_frame = rfcomm.RFCOMM_Frame.from_bytes(l2cap_pdu.payload)
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self.analyzer.emit(rfcomm_frame)
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elif psm == avdtp.AVDTP_PSM:
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self.analyzer.emit(
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f'{color("L2CAP", "green")} [CID={l2cap_pdu.cid}, '
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f'PSM=AVDTP]: {l2cap_pdu.payload.hex()}'
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)
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if avdtp_assembler := self.avdtp_assemblers.get(l2cap_pdu.cid):
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avdtp_assembler.on_pdu(l2cap_pdu.payload)
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elif psm == avctp.AVCTP_PSM:
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self.analyzer.emit(
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f'{color("L2CAP", "green")} [CID={l2cap_pdu.cid}, '
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f'PSM=AVCTP]: {l2cap_pdu.payload.hex()}'
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)
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if avctp_assembler := self.avctp_assemblers.get(l2cap_pdu.cid):
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avctp_assembler.on_pdu(l2cap_pdu.payload)
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else:
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psm_string = name_or_number(PSM_NAMES, psm)
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self.analyzer.emit(
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f'{color("L2CAP", "green")} [CID={l2cap_pdu.cid}, '
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f'PSM={psm_string}]: {l2cap_pdu.payload.hex()}'
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)
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else:
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self.analyzer.emit(l2cap_pdu)
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def on_avdtp_message(
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self, transaction_label: int, message: avdtp.Message
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) -> None:
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self.analyzer.emit(
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f'{color("AVDTP", "green")} [{transaction_label}] {message}'
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)
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def on_avctp_message(
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self,
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transaction_label: int,
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is_command: bool,
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ipid: bool,
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pid: int,
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payload: bytes,
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):
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if pid == avrcp.AVRCP_PID:
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avc_frame = avc.Frame.from_bytes(payload)
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details = str(avc_frame)
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else:
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details = payload.hex()
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c_r = 'Command' if is_command else 'Response'
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self.analyzer.emit(
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f'{color("AVCTP", "green")} '
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f'{c_r}[{transaction_label}][{name_or_number(AVCTP_PID_NAMES, pid)}] '
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f'{"#" if ipid else ""}'
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f'{details}'
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)
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def feed_packet(self, packet: HCI_AclDataPacket) -> None:
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self.packet_assembler.feed_packet(packet)
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class Analyzer:
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acl_streams: MutableMapping[int, PacketTracer.AclStream]
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peer: PacketTracer.Analyzer
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def __init__(self, label: str, emit_message: Callable[..., None]) -> None:
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self.label = label
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self.emit_message = emit_message
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self.acl_streams = {} # ACL streams, by connection handle
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self.packet_timestamp: datetime.datetime | None = None
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def start_acl_stream(self, connection_handle: int) -> PacketTracer.AclStream:
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logger.info(
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f'[{self.label}] +++ Creating ACL stream for connection '
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f'0x{connection_handle:04X}'
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)
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stream = PacketTracer.AclStream(self)
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self.acl_streams[connection_handle] = stream
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# Associate with a peer stream if we can
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if peer_stream := self.peer.acl_streams.get(connection_handle):
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stream.peer = peer_stream
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peer_stream.peer = stream
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return stream
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def end_acl_stream(self, connection_handle: int) -> None:
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if connection_handle in self.acl_streams:
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logger.info(
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f'[{self.label}] --- Removing ACL stream for connection '
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f'0x{connection_handle:04X}'
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)
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del self.acl_streams[connection_handle]
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# Let the other forwarder know so it can cleanup its stream as well
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self.peer.end_acl_stream(connection_handle)
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def on_packet(
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self, timestamp: datetime.datetime | None, packet: HCI_Packet
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) -> None:
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self.packet_timestamp = timestamp
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self.emit(packet)
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if packet.hci_packet_type == HCI_ACL_DATA_PACKET:
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acl_packet = cast(HCI_AclDataPacket, packet)
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# Look for an existing stream for this handle, create one if it is the
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# first ACL packet for that connection handle
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if (
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stream := self.acl_streams.get(acl_packet.connection_handle)
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) is None:
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stream = self.start_acl_stream(acl_packet.connection_handle)
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stream.feed_packet(acl_packet)
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elif packet.hci_packet_type == HCI_EVENT_PACKET:
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event_packet = cast(HCI_Event, packet)
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if event_packet.event_code == HCI_DISCONNECTION_COMPLETE_EVENT:
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self.end_acl_stream(
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cast(HCI_Disconnection_Complete_Event, packet).connection_handle
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)
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def emit(self, message: Any) -> None:
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if self.packet_timestamp:
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prefix = f"[{self.packet_timestamp.strftime('%Y-%m-%d %H:%M:%S.%f')}]"
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else:
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prefix = ""
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self.emit_message(f'{prefix}[{self.label}] {message}')
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def trace(
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self,
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packet: HCI_Packet,
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direction: int = 0,
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timestamp: datetime.datetime | None = None,
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) -> None:
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if direction == 0:
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self.host_to_controller_analyzer.on_packet(timestamp, packet)
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else:
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self.controller_to_host_analyzer.on_packet(timestamp, packet)
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def __init__(
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self,
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host_to_controller_label: str = color('HOST->CONTROLLER', 'blue'),
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controller_to_host_label: str = color('CONTROLLER->HOST', 'cyan'),
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emit_message: Callable[..., None] = logger.info,
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) -> None:
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self.host_to_controller_analyzer = PacketTracer.Analyzer(
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host_to_controller_label, emit_message
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)
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self.controller_to_host_analyzer = PacketTracer.Analyzer(
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controller_to_host_label, emit_message
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)
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self.host_to_controller_analyzer.peer = self.controller_to_host_analyzer
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self.controller_to_host_analyzer.peer = self.host_to_controller_analyzer
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def generate_irk() -> bytes:
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return crypto.r()
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def verify_rpa_with_irk(rpa: Address, irk: bytes) -> bool:
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rpa_bytes = bytes(rpa)
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prand_given = rpa_bytes[3:]
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hash_given = rpa_bytes[:3]
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hash_local = crypto.ah(irk, prand_given)
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return hash_local[:3] == hash_given
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