1# Copyright 2021-2022 Google LLC
2#
3# Licensed under the Apache License, Version 2.0 (the "License");
4# you may not use this file except in compliance with the License.
5# You may obtain a copy of the License at
6#
7#      https://www.apache.org/licenses/LICENSE-2.0
8#
9# Unless required by applicable law or agreed to in writing, software
10# distributed under the License is distributed on an "AS IS" BASIS,
11# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12# See the License for the specific language governing permissions and
13# limitations under the License.
14
15# -----------------------------------------------------------------------------
16# Imports
17# -----------------------------------------------------------------------------
18import logging
19
20from .hci import HCI_Packet
21from .helpers import PacketTracer
22
23# -----------------------------------------------------------------------------
24# Logging
25# -----------------------------------------------------------------------------
26logger = logging.getLogger(__name__)
27
28
29# -----------------------------------------------------------------------------
30class HCI_Bridge:
31    class Forwarder:
32        def __init__(self, hci_sink, sender_hci_sink, packet_filter, trace):
33            self.hci_sink = hci_sink
34            self.sender_hci_sink = sender_hci_sink
35            self.packet_filter = packet_filter
36            self.trace = trace
37
38        def on_packet(self, packet):
39            # Convert the packet bytes to an object
40            hci_packet = HCI_Packet.from_bytes(packet)
41
42            # Filter the packet
43            if self.packet_filter is not None:
44                filtered = self.packet_filter(hci_packet)
45                if filtered is not None:
46                    packet, respond_to_sender = filtered
47                    hci_packet = HCI_Packet.from_bytes(packet)
48                    if respond_to_sender:
49                        self.sender_hci_sink.on_packet(packet)
50                        return
51
52            # Analyze the packet
53            self.trace(hci_packet)
54
55            # Bridge the packet
56            self.hci_sink.on_packet(packet)
57
58    def __init__(
59        self,
60        hci_host_source,
61        hci_host_sink,
62        hci_controller_source,
63        hci_controller_sink,
64        host_to_controller_filter=None,
65        controller_to_host_filter=None,
66    ):
67        tracer = PacketTracer(emit_message=logger.info)
68        host_to_controller_forwarder = HCI_Bridge.Forwarder(
69            hci_controller_sink,
70            hci_host_sink,
71            host_to_controller_filter,
72            lambda packet: tracer.trace(packet, 0),
73        )
74        hci_host_source.set_packet_sink(host_to_controller_forwarder)
75
76        controller_to_host_forwarder = HCI_Bridge.Forwarder(
77            hci_host_sink,
78            hci_controller_sink,
79            controller_to_host_filter,
80            lambda packet: tracer.trace(packet, 1),
81        )
82        hci_controller_source.set_packet_sink(controller_to_host_forwarder)
83