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 asyncio
19import sys
20import os
21import logging
22
23from bumble.core import UUID
24from bumble.device import Device
25from bumble.transport import open_transport_or_link
26from bumble.rfcomm import Server
27from bumble.utils import AsyncRunner
28from bumble.rfcomm import make_service_sdp_records
29
30
31# -----------------------------------------------------------------------------
32def sdp_records(channel, uuid):
33    service_record_handle = 0x00010001
34    return {
35        service_record_handle: make_service_sdp_records(
36            service_record_handle, channel, UUID(uuid)
37        )
38    }
39
40
41# -----------------------------------------------------------------------------
42def on_rfcomm_session(rfcomm_session, tcp_server):
43    print('*** RFComm session connected', rfcomm_session)
44    tcp_server.attach_session(rfcomm_session)
45
46
47# -----------------------------------------------------------------------------
48class TcpServerProtocol(asyncio.Protocol):
49    def __init__(self, server):
50        self.server = server
51
52    def connection_made(self, transport):
53        peer_name = transport.get_extra_info('peer_name')
54        print(f'<<< TCP Server: connection from {peer_name}')
55        if self.server:
56            self.server.tcp_transport = transport
57        else:
58            transport.close()
59
60    def connection_lost(self, exc):
61        print('<<< TCP Server: connection lost')
62        if self.server:
63            self.server.tcp_transport = None
64
65    def data_received(self, data):
66        print(f'<<< TCP Server: data received: {len(data)} bytes - {data.hex()}')
67        if self.server:
68            self.server.tcp_data_received(data)
69
70
71# -----------------------------------------------------------------------------
72class TcpServer:
73    def __init__(self, port):
74        self.rfcomm_session = None
75        self.tcp_transport = None
76        AsyncRunner.spawn(self.run(port))
77
78    def attach_session(self, rfcomm_session):
79        if self.rfcomm_session:
80            self.rfcomm_session.sink = None
81
82        self.rfcomm_session = rfcomm_session
83        rfcomm_session.sink = self.rfcomm_data_received
84
85    def rfcomm_data_received(self, data):
86        print(f'<<< RFCOMM Data: {data.hex()}')
87        if self.tcp_transport:
88            self.tcp_transport.write(data)
89        else:
90            print('!!! no TCP connection, dropping data')
91
92    def tcp_data_received(self, data):
93        if self.rfcomm_session:
94            self.rfcomm_session.write(data)
95        else:
96            print('!!! no RFComm session, dropping data')
97
98    async def run(self, port):
99        print(f'$$$ Starting TCP server on port {port}')
100
101        server = await asyncio.get_running_loop().create_server(
102            lambda: TcpServerProtocol(self), '127.0.0.1', port
103        )
104
105        async with server:
106            await server.serve_forever()
107
108
109# -----------------------------------------------------------------------------
110async def main() -> None:
111    if len(sys.argv) < 4:
112        print(
113            'Usage: run_rfcomm_server.py <device-config> <transport-spec> '
114            '<tcp-port> [<uuid>]'
115        )
116        print('example: run_rfcomm_server.py classic2.json usb:0 8888')
117        return
118
119    tcp_port = int(sys.argv[3])
120
121    if len(sys.argv) >= 5:
122        uuid = sys.argv[4]
123    else:
124        uuid = 'E6D55659-C8B4-4B85-96BB-B1143AF6D3AE'
125
126    print('<<< connecting to HCI...')
127    async with await open_transport_or_link(sys.argv[2]) as hci_transport:
128        print('<<< connected')
129
130        # Create a device
131        device = Device.from_config_file_with_hci(
132            sys.argv[1], hci_transport.source, hci_transport.sink
133        )
134        device.classic_enabled = True
135
136        # Create a TCP server
137        tcp_server = TcpServer(tcp_port)
138
139        # Create and register an RFComm server
140        rfcomm_server = Server(device)
141
142        # Listen for incoming DLC connections
143        channel_number = rfcomm_server.listen(
144            lambda session: on_rfcomm_session(session, tcp_server)
145        )
146        print(f'### Listening for RFComm connections on channel {channel_number}')
147
148        # Setup the SDP to advertise this channel
149        device.sdp_service_records = sdp_records(channel_number, uuid)
150
151        # Start the controller
152        await device.power_on()
153
154        # Start being discoverable and connectable
155        await device.set_discoverable(True)
156        await device.set_connectable(True)
157
158        await hci_transport.source.wait_for_termination()
159
160
161# -----------------------------------------------------------------------------
162logging.basicConfig(level=os.environ.get('BUMBLE_LOGLEVEL', 'DEBUG').upper())
163asyncio.run(main())
164